WorldWideScience

Sample records for calcination

  1. Injector for calciner

    Energy Technology Data Exchange (ETDEWEB)

    Davis, R.L.; Edwards, D.L.; Graf, H.G.; Macbeth, W.B. Jr.

    1983-10-04

    Combustion gas such as air, oxygen-enriched air or oxygen is introduced to a calcining zone at an intermediate level in a vertical shaft kiln for the calcining of petroleum coke utilizing a plurality of radially disposed combustion gas injectors and at least one vertically disposed injector located within the shaft kiln and extending into the calcining zone. The injector includes means for circulating coolant around the periphery of the injector so that common metals may be used in the high temperature (above 2000/sup 0/ F.) environment of the shaft kiln. The vertical combustion gas injector may extend from the top of the calcining chamber to the calcining zone or from the bottom of the calcining chamber to the calcining zone. When the vertical combustion gas injector extends vertically upwardly from the bottom of the calcining chamber, means for introducing recycle gas to the calcining chamber may be incorporated into the vertical combustion gas injector.

  2. Calcine production and management

    International Nuclear Information System (INIS)

    The process technology related to calcination of power reactor wastes is summarized. The primary calcination processes developed are spray calcination, fluidized-bed calcination, and rotary kiln calcination. Calcines from the spray calciner and rotary kiln are fed directly to a glassification process. The fluidized-bed product can either be fed to a waste form conversion process or stored. The major process steps for calcinations are feed preparation, calcination and product handling, and off-gas cleanup. Feed systems for the three processes are basically similar. Gravity flow and pump pressurized systems have been used successfully. The major problems are fatigue failure of feed valve bellows, plugging by undissolved solids, and calibration of flowmeters. Process heat input is by electrical resistance heating for the spray and rotary kiln calciners and in-bed combustion or in-bed heat exchange for the fluidized-bed system. Low-melting solids which can cause scaling or solids agglomeration in any of the processes is a major calcination problem; however, feed blending, process operating conditions, and equipment design have successfully controlled solids agglomeration. Primary off-gas cleanup devices for particulates are cyclones, sintered metal filters, venturi scrubbers, and HEPA filters. Scrubbers, condensers, and solid adsorbents are used successfully for volatile ruthenium removal. The years of pilot-plant and plant-scale calcination testing and operation of the three systems have shown that reactor wastes can be calcined safely and practically. 11 figures, 2 tables

  3. Fluidized bed calciner apparatus

    Science.gov (United States)

    Owen, Thomas J.; Klem, Jr., Michael J.; Cash, Robert J.

    1988-01-01

    An apparatus for remotely calcining a slurry or solution feed stream of toxic or hazardous material, such as ammonium diurante slurry or uranyl nitrate solution, is disclosed. The calcining apparatus includes a vertical substantially cylindrical inner shell disposed in a vertical substantially cylindrical outer shell, in which inner shell is disposed a fluidized bed comprising the feed stream material to be calcined and spherical beads to aid in heat transfer. Extending through the outer and inner shells is a feed nozzle for delivering feed material or a cleaning chemical to the beads. Disposed in and extending across the lower portion of the inner shell and upstream of the fluidized bed is a support member for supporting the fluidized bed, the support member having uniform slots for directing uniform gas flow to the fluidized bed from a fluidizing gas orifice disposed upstream of the support member. Disposed in the lower portion of the inner shell are a plurality of internal electric resistance heaters for heating the fluidized bed. Disposed circumferentially about the outside length of the inner shell are a plurality of external heaters for heating the inner shell thereby heating the fluidized bed. Further, connected to the internal and external heaters is a means for maintaining the fluidized bed temperature to within plus or minus approximately 25.degree. C. of a predetermined bed temperature. Disposed about the external heaters is the outer shell for providing radiative heat reflection back to the inner shell.

  4. Calcination/dissolution residue treatment

    International Nuclear Information System (INIS)

    Currently, high-level wastes are stored underground in steel-lined tanks at the Hanford site. Current plans call for the chemical pretreatment of these wastes before their immobilization in stable glass waste forms. One candidate pretreatment approach, calcination/dissolution, performs an alkaline fusion of the waste and creates a high-level/low-level partition based on the aqueous solubilities of the components of the product calcine. Literature and laboratory studies were conducted with the goal of finding a residue treatment technology that would decrease the quantity of high-level waste glass required following calcination/dissolution waste processing. Four elements, Fe, Ni, Bi, and U, postulated to be present in the high-level residue fraction were identified as being key to the quantity of high-level glass formed. Laboratory tests of the candidate technologies with simulant high-level residues showed reductive roasting followed by carbonyl volatilization to be successful in removing Fe, Ni, and Bi. Subsequent bench-scale tests on residues from calcination/dissolution processing of genuine Hanford Site tank waste showed Fe was separated with radioelement decontamination factors of 70 to 1,000 times with respect to total alpha activity. Thermodynamic analyses of the calcination of five typical Hanford Site tank waste compositions also were performed. The analyses showed sodium hydroxide to be the sole molten component in the waste calcine and emphasized the requirement for waste blending if fluid calcines are to be achieved. Other calcine phases identified in the thermodynamic analysis indicate the significant thermal reconstitution accomplished in calcination

  5. Alternative calcination development status report

    International Nuclear Information System (INIS)

    The Programmatic Spent Nuclear Fuel and (INEEL) Environmental Restoration and Waste Management Programs Environmental Impact Statement Record of Decision, dated June 1, 1995, specifies that high-level waste stored in the underground tanks at the ICPP continue to be calcined while other options to treat the waste are studied. Therefore, the High-Level Waste Program has funded a program to develop new flowsheets to increase the liquid waste processing rate. Simultaneously, a radionuclide separation process, as well as other options, are also being developed, which will be compared to the calcination treatment option. Two alternatives emerged as viable candidates; (1) elevated temperature calcination (also referred to as high temperature calcination), and (2) sugar-additive calcination. Both alternatives were determined to be viable through testing performed in a lab-scale calcination mockup. Subsequently, 10-cm Calciner Pilot Plant scoping tests were successfully completed for both flowsheets. The results were compared to the standard 500 C, high-ANN flow sheet (baseline flowsheet). The product and effluent streams were characterized to help elucidate the process chemistry and to investigate potential environmental permitting issues. Several supplementary tests were conducted to gain a better understanding of fine-particles generation, calcine hydration, scrub foaming, feed makeup procedures, sugar/organic elimination, and safety-related issues. Many of the experiments are only considered to be scoping tests, and follow-up experiments will be required to establish a more definitive understanding of the flowsheets. However, the combined results support the general conclusion that flowsheet improvements for the NWCF are technically viable

  6. Dissolution properties of calcined gangue

    Institute of Scientific and Technical Information of China (English)

    Huajian Li; Henghu Sun; Xuchu Tie; Xuejun Xiao

    2006-01-01

    To study the dissolution mechanism of gangue, dissolution characteristics of the gangue samples calcined at different temperatures in alkaline solutions and alkali metal silicate solutions with respect to Si and A1 ions were analyzed by identical coupled plasma optical emission spectroscopy (ICP). The results show that the extent of dissolution of A1 and Si varies with calcination temperature. It shows that the samples have a higher degree of dissolution in NaOH than in KOH medium. Si and A1 appear to have synchro-dissolution behavior in alkaline solution, which means that Si and A1 could dissolve from the mineral surface in certain linked forms. The result that a higher degree of dissolution exists in sodium silicate solution and a lower degree of dissolution exists in sodium-potassium silicate solution of A1 is proved by the 29Si NMR spectra and the mean connectivity degree of these alkali metal silicate solutions.

  7. Summary of Waste Calcination at INTEC

    Energy Technology Data Exchange (ETDEWEB)

    O' Brien, Barry Henry; Newby, Bill Joe

    2000-10-01

    Fluidized-bed calcination at the Idaho Nuclear Technologies and Engineering Center (INTEC, formally called the Idaho Chemical Processing Plant) has been used to solidify acidic metal nitrate fuel reprocessing and incidental wastes wastes since 1961. A summary of waste calcination in full-scale and pilot plant calciners has been compiled for future reference. It contains feed compositions and operating conditions for all the processing campaigns for the original Waste Calcining Facility (WCF), the New Waste Calcining Facility (NWCF) started up in 1982, and numerous small scale pilot plant tests for various feed types. This summary provides a historical record of calcination at INTEC, and will be useful for evaluating calcinability of future wastes.

  8. Radiant-Heat Spray Calcination Studies

    International Nuclear Information System (INIS)

    The radiant-heat spray calcination process for conversion of liquid wastes to solids is described and the design of a one-gallon-per-hour spray calcination unit coupled with a small melt pot, capable of being run separately as a pot calciner, is discussed. The units were designed to test the feasibility of the calcination process with actual Purex plant waste in terms of the process as a unit operation, off-gas treatment, fission-product behaviour, condensate and calcined waste characteristics. The entire system was made to fit into an available 7-1/2 ft x 15 ft x 15 ft tall, manipulator-equipped, shielded cell which is also described. Included in the design discussion are: the resistance heating of the spray calciner column, thermal insulation of the column, spray nozzle, method of nozzle replacement, induction heating of the melt pot, radioactivity scanner for the pot, off-gas processing system including condenser, scrubber and filters, off-gas sampling device, liquid sampling device, wash-down system, feed system, instrumentation and control methods. The experience gained in operating the calciners and associated equipment is discussed. Experimental results presented show the effectiveness of off-gas decontamination and behaviour of gross chemical constituents and some specific fission products. (author)

  9. Calcined solids storage facility closure study

    International Nuclear Information System (INIS)

    The disposal of radioactive wastes now stored at the Idaho National Engineering and Environmental Laboratory is currently mandated under a open-quotes Settlement Agreementclose quotes (or open-quotes Batt Agreementclose quotes) between the Department of Energy and the State of Idaho. Under this agreement, all high-level waste must be treated as necessary to meet the disposal criteria and disposed of or made road ready to ship from the INEEL by 2035. In order to comply with this agreement, all calcined waste produced in the New Waste Calcining Facility and stored in the Calcined Solids Facility must be treated and disposed of by 2035. Several treatment options for the calcined waste have been studied in support of the High-Level Waste Environmental Impact Statement. Two treatment methods studied, referred to as the TRU Waste Separations Options, involve the separation of the high-level waste (calcine) into TRU waste and low-level waste (Class A or Class C). Following treatment, the TRU waste would be sent to the Waste Isolation Pilot Plant (WIPP) for final storage. It has been proposed that the low-level waste be disposed of in the Tank Farm Facility and/or the Calcined Solids Storage Facility following Resource Conservation and Recovery Act closure. In order to use the seven Bin Sets making up the Calcined Solids Storage Facility as a low-level waste landfill, the facility must first be closed to Resource Conservation and Recovery Act (RCRA) standards. This study identifies and discusses two basic methods available to close the Calcined Solids Storage Facility under the RCRA - Risk-Based Clean Closure and Closure to Landfill Standards. In addition to the closure methods, the regulatory requirements and issues associated with turning the Calcined Solids Storage Facility into an NRC low-level waste landfill or filling the bin voids with clean grout are discussed

  10. Activity and Structure of Calcined Coal Gangue

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Coal gangue was activated by means of calcination in seven temperature ranges. Systematic research was made about activation mechanism and structural evolution. Glycerin-ethanol method, SEM, MIP and XRD were used to determine the variation of structure and activation of coal gangue during the calcination.The experimental results show that because of heat treatment in the range of calcination temperature, mineral composition and microstructure of coal gangue are changed. In addition, its activity is improved evidently. The amount of lime absorbed by the sample calcined at 700 C is 2-4 times that by uncalcined coal gangue in the course of hydration. When NaOH is added to coal gangue-lime system, hydration reaction of the system is sped up and the microstructure of hydrating samples of coal gangue is improved.

  11. Bin Set 1 Calcine Retrieval Feasibility Study

    International Nuclear Information System (INIS)

    At the Department of Energy's Idaho Nuclear Technology and Engineering Center, as an interim waste management measure, both mixed high-level liquid waste and sodium bearing waste have been solidified by a calculation process and are stored in the Calcine Solids Storage Facilities. This calcined product will eventually be treated to allow final disposal in a national geologic repository. The Calcine Solids Storage Facilities comprise seven ''bit sets.'' Bin Set 1, the first to be constructed, was completed in 1959, and has been in service since 1963. It is the only bin set that does not meet current safe-shutdown earthquake seismic criteria. In addition, it is the only bin set that lacks built-in features to aid in calcine retrieval. One option to alleviate the seismic compliance issue is to transport the calcine from Bin Set 1 to another bin set which has the required capacity and which is seismically qualified. This report studies the feasibility of retrieving the calcine from Bi n Set 1 and transporting it into Bin Set 6 which is located approximately 650 feet away. Because Bin Set 1 was not designed for calcine retrieval, and because of the high radiation levels and potential contamination spread from the calcined material, this is a challenging engineering task. This report presents preconceptual design studies for remotely-operated, low-density, pneumatic vacuum retrieval and transport systems and equipment that are based on past work performed by the Raytheon Engineers and Constructors architectural engineering firm. The designs presented are considered feasible; however, future development work will be needed in several areas during the subsequent conceptual design phase

  12. Bin Set 1 Calcine Retrieval Feasibility Study

    Energy Technology Data Exchange (ETDEWEB)

    R. D. Adams; S. M. Berry; K. J. Galloway; T. A. Langenwalter; D. A. Lopez; C. M. Noakes; H. K. Peterson; M. I. Pope; R. J. Turk

    1999-10-01

    At the Department of Energy's Idaho Nuclear Technology and Engineering Center, as an interim waste management measure, both mixed high-level liquid waste and sodium bearing waste have been solidified by a calculation process and are stored in the Calcine Solids Storage Facilities. This calcined product will eventually be treated to allow final disposal in a national geologic repository. The Calcine Solids Storage Facilities comprise seven ''bit sets.'' Bin Set 1, the first to be constructed, was completed in 1959, and has been in service since 1963. It is the only bin set that does not meet current safe-shutdown earthquake seismic criteria. In addition, it is the only bin set that lacks built-in features to aid in calcine retrieval. One option to alleviate the seismic compliance issue is to transport the calcine from Bin Set 1 to another bin set which has the required capacity and which is seismically qualified. This report studies the feasibility of retrieving the calcine from Bi n Set 1 and transporting it into Bin Set 6 which is located approximately 650 feet away. Because Bin Set 1 was not designed for calcine retrieval, and because of the high radiation levels and potential contamination spread from the calcined material, this is a challenging engineering task. This report presents preconceptual design studies for remotely-operated, low-density, pneumatic vacuum retrieval and transport systems and equipment that are based on past work performed by the Raytheon Engineers and Constructors architectural engineering firm. The designs presented are considered feasible; however, future development work will be needed in several areas during the subsequent conceptual design phase.

  13. Experimental and modeling study of flash calcination of kaolinite rich clay particles in a gas suspension calciner

    DEFF Research Database (Denmark)

    Gebremariam, Abraham Teklay; Yin, Chungen; Rosendahl, Lasse;

    2015-01-01

    Calcination of kaolinite particles under appropriate conditions to produce materials that can replace part of the CO2 intensive clinker is gaining an increasing interest in cement industry worldwide. This paper presents a study of flash calcination of kaolinite rich clay particles in a pilot scale...... gas suspension calciner, with the aim to derive useful guidelines on smart calcination for obtaining products of the best pozzolanic properties. Calcination tests are performed in the calciner under six different operation conditions. The raw feed and the calcined clay samples are all characterized...

  14. 1st International Conference on Calcined Clays for Sustainable Concrete

    CERN Document Server

    Favier, Aurélie

    2015-01-01

    This volume focuses on research and practical issues linked to Calcined Clays for Sustainable Concrete. The main subjects are geology of clays, hydration and performance of blended systems with calcined clays, alkali activated binders, economic and environmental impacts of the use of calcined clays in cement based materials. Topics addressed in this book include the influence of processing on reactivity of calcined clays, influence of clay mineralogy on reactivity, geology of clay deposits, Portland-calcined clay systems, hydration, durability, performance, Portland-calcined clay-limestone systems, hydration, durability, performance, calcined clay-alkali systems, life cycle analysis, economics and environmental impact of use of calcined clays in cement and concrete, and field applications. This book compiles the different contributions of the 1st International Conference on Calcined Clays for Sustainable Concrete, which took place in Lausanne, Switzerland, June, 23-25, 2015.The papers present the latest  res...

  15. Modeling and Simulation of Petroleum Coke Calcination in Pot Calciner Using Two-Fluid Model

    Science.gov (United States)

    Xiao, Jin; Huang, Jindi; Zhong, Qifan; Zhang, Hongliang; Li, Jie

    2016-02-01

    The aim of this work was to establish a mathematical model for the analysis of calcining process of petroleum coke in a 24-pot calciner via computational fluid dynamics (CFD) numerical simulation method. The model can be divided into two main parts (1) heterogeneous reacting flow of petroleum coke calcination in the pot was simulated using a two-fluid model approach where the gas and solid phase are treated as a continuous phases; and (2) the standard turbulence equations combined with the finite rate/eddy-dissipation combustion model and discrete ordinates model were solved for the turbulent gas reacting flow in the flue. The model of the calcining process was implemented in ANSYS Fluent 15.0 (commercial CFD software) and validated by industrial production data. After the validation research, the model has been applied to inspect the distribution features of the temperature field in the furnace, the concentration field of residual moisture and volatiles in the petroleum coke, and the vector velocity field of gas and solid phases. This research can provide a theoretical basis for optimizing the structure and improving the automatic control level of a pot calciner.

  16. Experimental Test Plan for Grouting H-3 Calcine

    Energy Technology Data Exchange (ETDEWEB)

    Alan K. Herbst

    2006-01-01

    Approximately 4400 cubic meters of solid high-level waste called calcine are stored at the Idaho Nuclear Technology and Engineering Center. Under the Idaho Cleanup Project, dual disposal paths are being investigated. The first path includes calcine retrieval, package "as-is", and ship to the Monitored Geological Repository (MGR). The second path involves treatment of the calcine with such methods as vitrification or grouting. This test plan outlines the hot bench scale tests to grout actual calcine and verify that the waste form properties meet the waste acceptance criteria. This is a necessary sequential step in the process of qualifying a new waste form for repository acceptance. The archive H-3 calcine samples at the Contaminated Equipment Maintenance Building attached to New Waste Calcining Facility will be used in these tests at the Remote Analytical Laboratory. The tests are scheduled for the second quarter of fiscal year 2007.

  17. Calcination-Digestion-Desliming of Phosphorus Ore Bearing Rare Earth

    Institute of Scientific and Technical Information of China (English)

    Zhang Qin; Zhang Jie; Wang Jing; Qiu Yue qin

    2004-01-01

    The recoveries of phosphorus and RE of ore from Zhijin in Guizhou were studied.The influences of the calcination temperature, resident time, the digested time and water volume of the calcinating on concentrate yield by desliming were also investigated by orthogonal design.Appropriate calcination temperature is initial condition that makes carbonate mineral decomposition.The recovery of phosphorus is 83.02% and rare earth is 90.56% in phosphorus concentrate when calcined temperature is 900 ℃, other conditions include: calcined time is 30 min, digestion water volume is 300 ml, digestion time is 20 min.The results show that the pre-treatment of the ore is favorable for the separation and enrichment of rare earth from phosphorus ore, and a process of calcination-digestion-desliming was promised.

  18. Leaching characteristics of Idaho Chemical Processing Plant calcines

    International Nuclear Information System (INIS)

    This report documents leaching studies conducted on two non-radioactive, pilot-plant calcines produced at the Idaho Chemical Processing Plant. The two pilot-plant calcines simulate radioactive calcine which may be produced in the New Waste Calcining Facility by blending high-level liquid waste and sodium-bearing liquid waste. The calcines were subjected to the Environmental Protection Agency's Extraction Procedure Toxicity Test and to a test based on the Materials Characterization Center's MCC-1 Static Leach Test. Following the protocol of these tests, leachates were obtained and analyzed for chemical composition to develop information about component mass loss and total mass loss. Surface analysis techniques were employed in an attempt to identify species that were leached from the calcines, but later precipitated during the MCC-1 tests. This report also documents leaching studies conducted on a radioactive fluorinel-sodium blend calcine produced in the New Waste Calcining Facility. This calcine was also subjected to a static leach test based on the MCC-1 test. The leachate was analyzed to develop information about total mass loss and leaching characteristics of radioactive species. 12 refs., 9 figs., 9 tabs

  19. Recent advances in spray calcination of nuclear wastes

    International Nuclear Information System (INIS)

    Developments over the last two decades have led to the recent successful demonstration of large-scale spray calcination equipment. The calcination process is ready for full-scale radioactive plant application. The spray calciner is a relatively simple machine. Its components are few and uncomplicated; thus maintenance is minimal, and the equipment lends itself well to remote use. Perhaps the most attractive feature of the spray calciner is its ability to accept an extremely wide range of liquid waste feed compositions. A flow control valve has previously been used to regulate the feed rate to the calciner. Recent tests demonstrate that this item may be eliminated from the feed line, thereby simplifying the overall process flowsheet. Regulation of the atomizing gas-to-liquid feed line pressures can accurately control the liquid flow rate to the calciner. Various types of spray nozzles further allow flexibility in system design. An internal mix nozzle allows the system to operate using a pressurized feed system. Nozzle abrasion has been essentially eliminated by ceramic nozzle inserts. Designs of nonpressurized feed systems have been demonstrated. To insure negligible calcine holdup on the spray chamber wall, pneumatic vibrators have been successfully used for several years without problems. Studies have now been completed based upon vibrator tests to ascertain the long-term effect of vibrator operation on the calcination system. Results indicate that the spray calciner design would not be adversely affected by vibrator operation over a typical 20-year plant life cycle

  20. Leaching characteristics of Idaho Chemical Processing Plant calcines

    Energy Technology Data Exchange (ETDEWEB)

    Chipman, N A

    1990-02-01

    This report documents leaching studies conducted on two non-radioactive, pilot-plant calcines produced at the Idaho Chemical Processing Plant. The two pilot-plant calcines simulate radioactive calcine which may be produced in the New Waste Calcining Facility by blending high-level liquid waste and sodium-bearing liquid waste. The calcines were subjected to the Environmental Protection Agency's Extraction Procedure Toxicity Test and to a test based on the Materials Characterization Center's MCC-1 Static Leach Test. Following the protocol of these tests, leachates were obtained and analyzed for chemical composition to develop information about component mass loss and total mass loss. Surface analysis techniques were employed in an attempt to identify species that were leached from the calcines, but later precipitated during the MCC-1 tests. This report also documents leaching studies conducted on a radioactive fluorinel-sodium blend calcine produced in the New Waste Calcining Facility. This calcine was also subjected to a static leach test based on the MCC-1 test. The leachate was analyzed to develop information about total mass loss and leaching characteristics of radioactive species. 12 refs., 9 figs., 9 tabs.

  1. Mission Need Statement: Calcine Disposition Project Major Systems Acquisition Project

    International Nuclear Information System (INIS)

    This document identifies the need to establish the Calcine Disposition Project to determine and implement the final disposition of calcine including characterization, retrieval, treatment (if necessary), packaging, loading, onsite interim storage pending shipment to a repository or interim storage facility, and disposition of related facilities

  2. Modeling of calcination of single kaolinitic clay particle

    DEFF Research Database (Denmark)

    Gebremariam, Abraham Teklay; Yin, Chungen; Rosendahl, Lasse

    The present work aims at modeling of the calcination (dehydroxylation) process of clay particles, specifically kaolinite, and its thermal transformation. For such purpose, 1D single particle calcination model was developed based on the concept of shrinking core model to assess the dehydroxylation...

  3. Properties of Formula 127 glass prepared with radioactive zirconia calcine

    International Nuclear Information System (INIS)

    Formula 127 glass has been developed to immobilize ICPP zirconia calcine. This glass has been prepared remotely on a laboratory scale basis with actual radioactive zirconia calcine retrieved after ten years of storage from Bin Set 2. The aqueous leachability of the glass produced was investigated and compared through application of the MCC-1, MCC-2 and Soxhlet leach tests with that of Formula 127 glass prepared with simulated calcine. The solid state properties of the glasses prepared with actual and simulated calcines were also measured by electron spectroscopy for chemical analysis (ESCA) and scanning electron microscopy energy dispersive x-ray (SEM-EDX). Based on the application of these leaching tests and analysis techniques the properties measured in this study are similar for 127 glass prepared with either simulated or radioactive calcine. 13 figures, 16 tables

  4. Calcination/dissolution testing for Hanford Site tank wastes

    Energy Technology Data Exchange (ETDEWEB)

    Colby, S.A.; Delegard, C.H. [Westinghouse Hanford Co., Richland, WA (United States); McLaughlin, D.F. [Westinghouse Science and Technology Center, Pittsburgh, PA (United States); Danielson, M.J. [Pacific Northwest Lab., Richland, WA (United States)

    1994-07-01

    Thermal treatment by calcination offers several benefits for the treatment of Hanford Site tank wastes, including the destruction of organics and ferrocyanides and an hydroxide fusion that permits the bulk of the mostly soluble nonradioactive constituents to be easily separated from the insoluble transuranic residue. Critical design parameters were tested, including: (1) calciner equipment design, (2) hydroxide fusion chemistry, and (3) equipment corrosion. A 2 gal/minute pilot plant processed a simulated Tank 101-SY waste and produced a free flowing 700 C molten calcine with an average calciner retention time of 20 minutes and >95% organic, nitrate, and nitrite destruction. Laboratory experiments using actual radioactive tank waste and the simulated waste pilot experiments indicate that 98 wt% of the calcine produced is soluble in water, leaving an insoluble transuranic fraction. All of the Hanford Site tank wastes can benefit from calcination/dissolution processing, contingent upon blending various tank waste types to ensure a target of 70 wt% sodium hydroxide/nitrate/nitrite fluxing agent. Finally, corrosion testing indicates that a jacketed nickel liner cooled to below 400 C would corrode <2 mil/year (0.05 mm/year) from molten calcine attack.

  5. Enhanced Photocatalytic Activity of Powders (P25 via Calcination Treatment

    Directory of Open Access Journals (Sweden)

    Guohong Wang

    2012-01-01

    Full Text Available P25 TiO2 powders were calcined at different temperatures in a muffle furnace in air. The P25 powders before and after calcination treatment were characterized with XRD FTIR, UV-visible diffuse reflectance spectra, SEM, TEM, HRTEM, and N2 adsorption-desorption measurements. The photocatalytic activity was evaluated by the photocatalytic oxidation of methyl orange aqueous solution under UV light irradiation in air. The results showed that calcination treatment obviously influenced the microstructures and photocatalytic activity of the P25 TiO2 powders. The synergistic effect of the phase structure, BET surface area, and crystallinity on the photocatalytic of TiO2 powders (P25 after calcination was investigated. An optimal calcination temperature ( was determined. The photocatalytic activity of TiO2 powders calcined at was nearly 2 times higher than that of the uncalcined P25 TiO2. The highest photocatalytic activities of the calcined samples at for 4 h might be ascribed to the enhancement of anatase crystallization and the optimal mass ratio (ca. 1 : 2 of rutile to anatase.

  6. Summary of Calcine Disposal Development Using Hot Isostatic Pressing

    Energy Technology Data Exchange (ETDEWEB)

    Bateman, Ken [Idaho National Lab. (INL), Idaho Falls, ID (United States); Wahlquist, Dennis [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hart, Edward [Idaho National Lab. (INL), Idaho Falls, ID (United States); McCartin, William [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-03-01

    Battelle Energy Alliance, LLC, has demonstrated the effectiveness of the hot isostatic press (HIP) process for treatment of hazardous high-level waste known as calcine that is stored at the Idaho Nuclear Technology and Engineering Center (INTEC) at Idaho National Laboratory. HIP trials performed with simulated calcines at Idaho National Laboratory’s Materials and Fuels Complex and an Australian Nuclear Science and Technology Organization facility from 2007 to 2010 produced a dense, monolithic waste form with increased chemical durability and effective (storage) volume reductions of ~10 to ~70% compared to granular calcine forms. In December 2009, the U.S. Department of Energy signed an amended Record of Decision selecting HIP technology as the treatment method for the 4,400 m3 of granular zirconia and alumina calcine stored at INTEC. Testing showed that HIP treatment reduces the risks associated with radioactive and hazardous constituent release, post-production handling, and long-term (repository) storage of calcines and would result in estimated storage cost savings in the billions of dollars. Battelle Energy Alliance has the ability to complete pilot-scale HIP processing of INTEC calcine, which is the next necessary step in implementing HIP processing as a calcine treatment method.

  7. Structural Integrity Program for INTEC Calcined Solids Storage Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Jeffrey Bryant

    2008-08-30

    This report documents the activities of the structural integrity program at the Idaho Nuclear Technology and Engineering Center relevant to the high-level waste Calcined Solids Storage Facilities and associated equipment, as required by DOE M 435.1-1, 'Radioactive Waste Management Manual'. Based on the evaluation documented in this report, the Calcined Solids Storage Facilities are not leaking and are structurally sound for continued service. Recommendations are provided for continued monitoring of the Calcined Solids Storage Facilities.

  8. Calcine Waste Storage at the Idaho Nuclear Technology and Engineering Center

    Energy Technology Data Exchange (ETDEWEB)

    Staiger, Merle Daniel; M. C. Swenson

    2005-01-01

    This report documents an inventory of calcined waste produced at the Idaho Nuclear Technology and Engineering Center during the period from December 1963 to May 2000. The report was prepared based on calciner runs, operation of the calcined solids storage facilities, and miscellaneous operational information that establishes the range of chemical compositions of calcined waste stored at Idaho Nuclear Technology and Engineering Center. The report will be used to support obtaining permits for the calcined solids storage facilities, possible treatment of the calcined waste at the Idaho National Engineering and Environmental Laboratory, and to ship the waste to an off-site facility including a geologic repository. The information in this report was compiled from calciner operating data, waste solution analyses and volumes calcined, calciner operating schedules, calcine temperature monitoring records, and facility design of the calcined solids storage facilities. A compact disk copy of this report is provided to facilitate future data manipulations and analysis.

  9. CSER 97-004: PFP production denitration calciner system

    International Nuclear Information System (INIS)

    The plutonium stabilization program at the Plutonium Finishing Plant (PFP) includes conversion of acidic plutonium nitrate solution into plutonium oxide. Conversion is facilitated through use of a vertical calciner installed in Glovebox HC-23OC-2, which is located in RM 230C of this facility. This evaluation supports the Criticality Prevention Specification for the calcining process inside this glovebox. As the product of the calciner is a high density plutonium oxide, a number of limits are required to insure criticality safety. The containers allowed are product receiver vessels and 0.5 C slip lid cans and polyjars. The limits allow for two ''unit masses'' of 2 V total volume each, separated by a distance of at least 25.4 cm (10 in.). This evaluation allows for operation of the calciner for product densities not in excess of 5.5 g Pu/cm3

  10. CSER 97-004: PFP production denitration calciner system

    Energy Technology Data Exchange (ETDEWEB)

    Hillesland, K.E.

    1997-09-11

    The plutonium stabilization program at the Plutonium Finishing Plant (PFP) includes conversion of acidic plutonium nitrate solution into plutonium oxide. Conversion is facilitated through use of a vertical calciner installed in Glovebox HC-23OC-2, which is located in RM 230C of this facility. This evaluation supports the Criticality Prevention Specification for the calcining process inside this glovebox. As the product of the calciner is a high density plutonium oxide, a number of limits are required to insure criticality safety. The containers allowed are product receiver vessels and 0.5 C slip lid cans and polyjars. The limits allow for two ``unit masses`` of 2 V total volume each, separated by a distance of at least 25.4 cm (10 in.). This evaluation allows for operation of the calciner for product densities not in excess of 5.5 g Pu/cm{sup 3}.

  11. Microstructural changes in porous hematite nanoparticles upon calcination

    DEFF Research Database (Denmark)

    Johnsen, Rune; Knudsen, Kenneth D.; Molenbroek, Alfons M.

    2011-01-01

    This combined study using small-angle neutron scattering (SANS), X-ray powder diffraction (XRPD), transmission electron microscopy (TEM) and adsorption isotherm techniques demonstrates radical changes in the microstructure of porous hematite (-Fe2O3) nanoparticles upon calcination in air. TEM...... from the particle size and the other from the pore/void structure. Furthermore, the TEM images show that the particle sizes are nearly unaffected by calcination at 623 K, whereas their pore/void structure changes radically to an apparently pitted or spongy microstructure with cavities or/and voids....... The change in microstructure also causes a reduction in the surface area as calculated by gaseous adsorption. The XRPD and SANS data show that the crystallite and SANS particle sizes are virtually unchanged by calcination at 623 K. Calcination at 973 K induces a significant alteration of the sample. The XRPD...

  12. Crystallographic transformation of limestone during calcination under CO2.

    Science.gov (United States)

    Valverde, Jose Manuel; Medina, Santiago

    2015-09-14

    The calcination reaction of limestone (CaCO3) to yield lime (CaO) is at the heart of many industrial applications as well as natural processes. In the recently emerged calcium-looping technology, CO2 capture is accomplished by the carbonation of CaO in a gas-solid reactor (carbonator). CaO is derived by the calcination of limestone in a calciner reactor under necessarily high CO2 partial pressure and high temperature. In situ X-ray diffraction (XRD) has been employed in this work to gain further insight into the crystallographic transformation that takes place during the calcination of limestone under CO2, at partial pressures (P) close to the equilibrium pressure (Peq) and at high temperature. Calcination under these conditions becomes extremely slow. The in situ XRD analysis presented here suggests the presence of an intermediate metastable CaO* phase stemming from the parent CaCO3 structure. According to the reaction mechanism proposed elsewhere, the exothermicity of the CaO* → CaO transformation and high values of P/Peq inhibit the nucleation of CaO at high temperatures. The wt% of CaO* remains at a relatively high level during slow calcination. Two diverse stages have been identified in the evolution of CaO crystallite size, L. Initially, L increases with CaCO3 conversion, following a logarithmic law. Slow calcination allows the crystallite size to grow up from a few nanometers at nucleation up to around 100 nm near the end of conversion. Otherwise, quick calcination at relatively lower CO2 concentrations limits CaO crystallite growth. Once calcination reaches an advanced state, the presence of CaO* drops to zero and the rate of increase of the CaO crystallite size is significantly hindered. Arguably, the first stage in CaO crystallite growth is driven by aggregation of the metastable CaO* nanocrystals, due to surface attractive forces, whereas the second one is consistent with sintering of the aggregated CaO crystals, and persists with time after full

  13. CSER 99-001: PFP LAB Dentirating calciner

    International Nuclear Information System (INIS)

    A criticality safety evaluation report was prepared for the Plutonium Finishing Plant (PFP) laboratory denigrating calciner, located in Glovebox 188-1, that converts Pu(NO3)4 solutions to the high fired stable oxide PuO2. Fissile mass limits and volume limits are set for the glovebox for testing operations and training operators using only nitric acid feed to a plutonium oxide bed in the calciner

  14. CSER 99-001: PFP LAB Dentirating calciner

    Energy Technology Data Exchange (ETDEWEB)

    MILLER, E.M.; DOBBIN, K.D.

    1999-02-22

    A criticality safety evaluation report was prepared for the Plutonium Finishing Plant (PFP) laboratory denigrating calciner, located in Glovebox 188-1, that converts Pu(NO{sub 3}){sub 4} solutions to the high fired stable oxide PuO{sub 2}. Fissile mass limits and volume limits are set for the glovebox for testing operations and training operators using only nitric acid feed to a plutonium oxide bed in the calciner.

  15. The Kinetics of Calcination of High Calcium Limestone

    Directory of Open Access Journals (Sweden)

    P. C. Okonkwo

    2012-02-01

    Full Text Available The kinetics of calcination of a high calcium type of limestone was studied. Ukpilla limestone found in the central region of Nigeria was studied. The limestone composition shows that the limestone has 51.29% calcium oxide and 41.53% loss on ignition and magnesium oxide content of 2.23%. The following parameters were determined; diffusion coefficient of lime layer, and mass transfer coefficient, conductivity of lime layer and beat transfer coefficient, convective parameter and diffusive parameter for temperatures 9000C, 10000C, 10600C and 10800C. The reaction was found to be limited by mass and heat transfers across the tune layer of the calcining article, theoptimal temperature of calcination was found to be 10600C. Diffusivity and mass transfer coefficient decreases with increase in calcination temperature. The thermal conductivity increases with increase in temperature. The diffusive and convective parameter decreases with increase in temperature. The reactivity of lime calcined at different temperatures were determined. The reactivity of the lime increases with decrease in calcination temperature.

  16. Adsorption removal of thiocyanate from aqueous solution by calcined hydrotalcite

    Institute of Scientific and Technical Information of China (English)

    LI Yu-jiang; YANG Min; ZHANG Xiao-jin; WU Tao; CAO Nan; WEI Na; BI Yan-jun; WANG Jing

    2006-01-01

    A hydrotalcite with Mg/Al molar ratio 2 was prepared by co-precipitation method and was characterized by XRD,TG/DTA, Zeta potential and BET surface area. The hydrotalcite was calcined at 500℃, with the dehydration from interlayer, the dehydroxilation from the brucite-like layer and the decomposition of carbonate successively, transformed into the mixed oxide type.The removal of thiocyanate from aqueous solution by using the original hydrotalcite and calcined hydrotalcite (HTC-500) was investigated. The results showed that the thiocyanate adsorption capacity of calcined hydrotalcite was much higher than that of the original form. Calcined hydrotalcite was particularly effective at removing thiocyanate, and that the effective range of pH for the thiocyanate removal are between 5.5-10.0. The experimental data of thiocyanate removal fit nicely with Langmuir isotherm, and the saturated adsorption uptake was 96.2 mg SCN-/g HTC-500. The adsorption ofthiocyanate by calcined hydrotalcite follows first-order kinetics. And the intercalation to the structure recovery for calcined hydrotalcite. But the presence of additional anions could affect the adsorption behavior of thiocyanate.

  17. Structure transition of nano-titania during calcination

    Institute of Scientific and Technical Information of China (English)

    李国华; 王大伟; 徐铸德; 陈卫祥

    2003-01-01

    In order to study the structure transition during calcination, nano-titania powders prepared by hydrolyzing precipitation approach and calcined at 300, 400, 500, 600 and 700 ℃ were characterized by XRD, TEM and electron diffraction(ED), respectively. The results show that titania powders calcined below 500 ℃ are almost composed of anatase, rutile appears below 500 ℃ and its ratio increases gradually with increase of calcin temperature;nano-titania particles are smaller than 40 nm mostly and the dispersion is related to calcining temperature; the interplanar distances of nano-anatase single crystalline change gradually when calcing temperature increases to 500 ℃; so do that of nano-rutile single crystalline when calcining temperature charges from 600 to 700 ℃. The conclusions can be drawn that the temperature of transformation from anatase to rutile is below 500 ℃ and the process carries on gradually. Both inter-planar distances and the structure of nano-titania transform gradually with increasing calcing temperature.

  18. High Temperature Calcination - MACT Upgrade Equipment Pilot Plant Test

    Energy Technology Data Exchange (ETDEWEB)

    Richard D. Boardman; B. H. O& #39; Brien; N. R. Soelberg; S. O. Bates; R. A. Wood; C. St. Michel

    2004-02-01

    About one million gallons of acidic, hazardous, and radioactive sodium-bearing waste are stored in stainless steel tanks at the Idaho Nuclear Technology and Engineering Center (INTEC), which is a major operating facility of the Idaho National Engineering and Environmental Laboratory. Calcination at high-temperature conditions (600 C, with alumina nitrate and calcium nitrate chemical addition to the feed) is one of four options currently being considered by the Department of Energy for treatment of the remaining tank wastes. If calcination is selected for future processing of the sodium-bearing waste, it will be necessary to install new off-gas control equipment in the New Waste Calcining Facility (NWCF) to comply with the Maximum Achievable Control Technology (MACT) standards for hazardous waste combustors and incinerators. This will require, as a minimum, installing a carbon bed to reduce mercury emissions from their current level of up to 7,500 to <45 {micro}g/dscm, and a staged combustor to reduce unburned kerosene fuel in the off-gas discharge to <100 ppm CO and <10 ppm hydrocarbons. The staged combustor will also reduce NOx concentrations of about 35,000 ppm by 90-95%. A pilot-plant calcination test was completed in a newly constructed 15-cm diameter calciner vessel. The pilot-plant facility was equipped with a prototype MACT off-gas control system, including a highly efficient cyclone separator and off-gas quench/venturi scrubber for particulate removal, a staged combustor for unburned hydrocarbon and NOx destruction, and a packed activated carbon bed for mercury removal and residual chloride capture. Pilot-plant testing was performed during a 50-hour system operability test January 14-16, followed by a 100-hour high-temperature calcination pilot-plant calcination run January 19-23. Two flowsheet blends were tested: a 50-hour test with an aluminum-to-alkali metal molar ratio (AAR) of 2.25, and a 50-hour test with an AAR of 1.75. Results of the testing

  19. Calcined Waste Storage at the Idaho Nuclear Technology and Engineering Center

    Energy Technology Data Exchange (ETDEWEB)

    Staiger, M. Daniel, Swenson, Michael C.

    2011-09-01

    This comprehensive report provides definitive volume, mass, and composition (chemical and radioactivity) of calcined waste stored at the Idaho Nuclear Technology and Engineering Center. Calcine composition data are required for regulatory compliance (such as permitting and waste disposal), future treatment of the caline, and shipping the calcine to an off-Site-facility (such as a geologic repository). This report also contains a description of the calcine storage bins. The Calcined Solids Storage Facilities (CSSFs) were designed by different architectural engineering firms and built at different times. Each CSSF has a unique design, reflecting varying design criteria and lessons learned from historical CSSF operation. The varying CSSF design will affect future calcine retrieval processes and equipment. Revision 4 of this report presents refinements and enhancements of calculations concerning the composition, volume, mass, chemical content, and radioactivity of calcined waste produced and stored within the CSSFs. The historical calcine samples are insufficient in number and scope of analysis to fully characterize the entire inventory of calcine in the CSSFs. Sample data exist for all the liquid wastes that were calcined. This report provides calcine composition data based on liquid waste sample analyses, volume of liquid waste calcined, calciner operating data, and CSSF operating data using several large Microsoft Excel (Microsoft 2003) databases and spreadsheets that are collectively called the Historical Processing Model. The calcine composition determined by this method compares favorably with historical calcine sample data.

  20. Human health risk characterization of petroleum coke calcining facility emissions.

    Science.gov (United States)

    Singh, Davinderjit; Johnson, Giffe T; Harbison, Raymond D

    2015-12-01

    Calcining processes including handling and storage of raw petroleum coke may result in Particulate Matter (PM) and gaseous emissions. Concerns have been raised over the potential association between particulate and aerosol pollution and adverse respiratory health effects including decrements in lung function. This risk characterization evaluated the exposure concentrations of ambient air pollutants including PM10 and gaseous pollutants from a petroleum coke calciner facility. The ambient air pollutant levels were collected through monitors installed at multiple locations in the vicinity of the facility. The measured and modeled particulate levels in ambient air from the calciner facility were compared to standards protective of public health. The results indicated that exposure levels were, on occasions at sites farther from the facility, higher than the public health limit of 150 μg/m(3) 24-h average for PM10. However, the carbon fraction demonstrated that the contribution from the calciner facility was de minimis. Exposure levels of the modeled SO2, CO, NOx and PM10 concentrations were also below public health air quality standards. These results demonstrate that emissions from calcining processes involving petroleum coke, at facilities that are well controlled, are below regulatory standards and are not expected to produce a public health risk. PMID:26520182

  1. Human health risk characterization of petroleum coke calcining facility emissions.

    Science.gov (United States)

    Singh, Davinderjit; Johnson, Giffe T; Harbison, Raymond D

    2015-12-01

    Calcining processes including handling and storage of raw petroleum coke may result in Particulate Matter (PM) and gaseous emissions. Concerns have been raised over the potential association between particulate and aerosol pollution and adverse respiratory health effects including decrements in lung function. This risk characterization evaluated the exposure concentrations of ambient air pollutants including PM10 and gaseous pollutants from a petroleum coke calciner facility. The ambient air pollutant levels were collected through monitors installed at multiple locations in the vicinity of the facility. The measured and modeled particulate levels in ambient air from the calciner facility were compared to standards protective of public health. The results indicated that exposure levels were, on occasions at sites farther from the facility, higher than the public health limit of 150 μg/m(3) 24-h average for PM10. However, the carbon fraction demonstrated that the contribution from the calciner facility was de minimis. Exposure levels of the modeled SO2, CO, NOx and PM10 concentrations were also below public health air quality standards. These results demonstrate that emissions from calcining processes involving petroleum coke, at facilities that are well controlled, are below regulatory standards and are not expected to produce a public health risk.

  2. Apatite formation on calcined kaolin-white Portland cement geopolymer.

    Science.gov (United States)

    Pangdaeng, S; Sata, V; Aguiar, J B; Pacheco-Torgal, F; Chindaprasirt, P

    2015-06-01

    In this study, calcined kaolin-white Portland cement geopolymer was investigated for use as biomaterial. Sodium hydroxide and sodium silicate were used as activators. In vitro test was performed with simulated body fluid (SBF) for bioactivity characterization. The formation of hydroxyapatite bio-layer on the 28-day soaked samples surface was tested using SEM, EDS and XRD analyses. The results showed that the morphology of hydroxyapatite was affected by the source material composition, alkali concentration and curing temperature. The calcined kaolin-white Portland cement geopolymer with relatively high compressive strength could be fabricated for use as biomaterial. The mix with 50% white Portland cement and 50% calcined kaolin had 28-day compressive strength of 59.0MPa and the hydroxyapatite bio-layer on the 28-day soaked sample surface was clearly evident.

  3. Total oxidation of toluene over calcined trimetallic hydrotalcites type catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Palacio, Luz A. [Instituto Superior Tecnico, IBB - Centro de Engenharia Biologica e Quimica, Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Grupo Catalizadores y Adsorbentes, Universidad de Antioquia 1-317, A.A. 1226 Medellin (Colombia); Velasquez, Juliana; Echavarria, Adriana [Grupo Catalizadores y Adsorbentes, Universidad de Antioquia 1-317, A.A. 1226 Medellin (Colombia); Faro, Arnaldo [Departamento de Fisicoquimica, Instituto de Quimica, Universidade Federal do Rio de Janeiro, Ilha do Fundao, CT bloco A, Rio de Janeiro (Brazil); Ramoa Ribeiro, F. [Instituto Superior Tecnico, IBB - Centro de Engenharia Biologica e Quimica, Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Ribeiro, M. Filipa, E-mail: filipa.ribeiro@ist.utl.pt [Instituto Superior Tecnico, IBB - Centro de Engenharia Biologica e Quimica, Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal)

    2010-05-15

    Two trimetallic ZnCuAl and MnCuAl hydrotalcites have been successfully synthesized by a co-precipitation method. The manganese based material was identified as a new hydrotalcite phase. Both lamellar precursors were calcined at 450 and 600 deg. C and the resulting catalysts were tested on reaction of total oxidation of toluene. The solids were characterized by X-ray diffraction, thermal analysis, atomic absorption spectroscopy, Fourier transformed infrared spectroscopy, N{sub 2} adsorption and H{sub 2} temperature-programmed reduction. It was found that ZnCuAl materials are composed of copper and zinc oxides supported on alumina; while MnCuAl ones comprise basically spinel phases, which were not completely identified. The catalytic behavior of the calcined samples showed that Mn hydrotalcite calcined at 450 deg. C exhibited the best catalytic performance that corresponds to 100% toluene conversion into CO{sub 2} at about 300 deg. C.

  4. Apatite formation on calcined kaolin-white Portland cement geopolymer.

    Science.gov (United States)

    Pangdaeng, S; Sata, V; Aguiar, J B; Pacheco-Torgal, F; Chindaprasirt, P

    2015-06-01

    In this study, calcined kaolin-white Portland cement geopolymer was investigated for use as biomaterial. Sodium hydroxide and sodium silicate were used as activators. In vitro test was performed with simulated body fluid (SBF) for bioactivity characterization. The formation of hydroxyapatite bio-layer on the 28-day soaked samples surface was tested using SEM, EDS and XRD analyses. The results showed that the morphology of hydroxyapatite was affected by the source material composition, alkali concentration and curing temperature. The calcined kaolin-white Portland cement geopolymer with relatively high compressive strength could be fabricated for use as biomaterial. The mix with 50% white Portland cement and 50% calcined kaolin had 28-day compressive strength of 59.0MPa and the hydroxyapatite bio-layer on the 28-day soaked sample surface was clearly evident. PMID:25842101

  5. Talc-based cementitious products: Effect of talc calcination

    Directory of Open Access Journals (Sweden)

    C.J. Ngally Sabouang

    2015-09-01

    Full Text Available This study reports the use of calcined talc for cementitious products making. The calcination is used to enhance the availability of magnesium from talc to react with phosphate for cement phase formation. It is shown that previous calcination of talc leads to products having enhanced mechanical performance due to the formation of more cement phase than in products based on raw talc. Talc fired at 900 °C was found to be the one in which magnesium release was maximal. Firing at temperature higher than 900 °C leads to the stabilization of enstatite, which decreased the magnesium availability. The cement phase is struvite, which was better detected on the X-ray patterns of the products involving fired talc. All the products have very rapid setting time and low shrinkage.

  6. Dissolution kinetics of ulexite prepared under different calcination temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Demirkiran, N.; Kuenkuel, A. [Inonu University, Malatya (Turkey). Faculty of Engineering. Dept. of Chemical Engineering]. E-mail: ndemirkiran@inonu.edu.tr

    2008-10-15

    Ulexite is one of the boron minerals used as a raw material in the production of boron compounds. It contains a substantial amount of hydration water. Using calcination methods, the B{sub 2}O{sub 3} grade of ulexite can be increased. In this study, the effect of calcination temperature on dissolution kinetics of ulexite in ammonium chloride solutions was investigated in a batch reactor employing the parameters of concentration, solid-to-liquid ratio and reaction temperature. It was found that the dissolution rate increased with increasing concentration and reaction temperature and with decreasing solid-to-liquid ratio. The highest dissolution rate was obtained with the sample calcined at 413 K. It was determined that the dissolution rate fit to the second order pseudo-homogeneous model. The activation energy of this dissolution process was found to be 64.3 kJ/mo L. (author)

  7. Spray calcination/in-can melting: effluent characterization and treatment

    International Nuclear Information System (INIS)

    According to data obtained during calcination of nonradioactive, simulated waste, ruthenium and cesium losses from the spray calciner are small, on the order of 3.5 x 10-2% and 3.4 x 10-2%, respectively. Calciner-melter and filter decontamination factors for ruthenium and cesium averaged 3.6 x 104 and 3.9 x 104, respectively. Particulate decontamination factors of 103 to 104 have been obtained using sintered stainless steel filters. A significant portion of the ruthenium and cesium lost to the process off-gas system was due to particle penetration of the filters. The particles penetrating the filters have a mass distribution centering about a size large enough to control with available technology. Processing wastes containing fluoride will probably volatilize a portion of the fluoride to the off-gas system, thus increasing the probability of corrosion problems. 34 figures, 30 tables

  8. CSER 95-005: PFP vertical denitration calciner

    International Nuclear Information System (INIS)

    The Vertical Denitrating Calciner system will stabilize certain unique solutions containing fissile salts by removing the water and nitrate ion to produce a more easily stored powder. This end is achieved by high-firing the solution in the calciner. The resultant calcine is distinguished by particles which are larger and denser than those produced by the more conventional oxalate precipitation process. This criticality safety evaluation report examines criticality safety for the denitration system, installed in glovebox 188-1 at PFP. The examination shows that, due to the incorporation of standard criticality safety design techniques, the glovebox can be maintained subcritical with minimal reliance on administrative controls. The examination also shows that, ignoring the necessary administrative controls can make a criticality possible in glovebox 188-1. Section 3.0 of this report lists the necessary administrative controls

  9. Morphology, crystal structure and hydration of calcined and modified anhydrite

    Institute of Scientific and Technical Information of China (English)

    Xiao-qing Niu; Ji-chun Chen

    2014-01-01

    The effects of calcination and modification on the morphology (shapes and textures) and crystal structure of anhydrite powders were studied. The results show that, calcination at 100°C causes anhydrite to disintegrate into smaller crystals, accompanied by a slight in-crease in d-spacing. Without calcination and modification, the solidification time and curing time of anhydrite are 15 and 77 h, respectively. After the treatment, however, the solidification time and curing time are shortened significantly to 9.5 and 14 min, respectively. The com-pressive and flexural strengths of hydration products made from the treated anhydrite reach 10.2 and 2.0 MPa, respectively. The much shorter solidification and curing time make it possible to use anhydrite as a building and construction material.

  10. Calcine Waste Storage at the Idaho Nuclear Technology and Engineering Center

    Energy Technology Data Exchange (ETDEWEB)

    M. D. Staiger

    1999-06-01

    A potential option in the program for long-term management of high-level wastes at the Idaho Nuclear Technology and Engineering Center (INTEC), at the Idaho National Engineering and Environmental Laboratory, calls for retrieving calcine waste and converting it to a more stable and less dispersible form. An inventory of calcine produced during the period December 1963 to May 1999 has been prepared based on calciner run, solids storage facilities operating, and miscellaneous operational information, which gives the range of chemical compositions of calcine waste stored at INTEC. Information researched includes calciner startup data, waste solution analyses and volumes calcined, calciner operating schedules, solids storage bin capacities, calcine storage bin distributor systems, and solids storage bin design and temperature monitoring records. Unique information on calcine solids storage facilities design of potential interest to remote retrieval operators is given.

  11. Photocatalyst Nanofibers Obtained by Calcination of Organic-Inorganic Hybrids

    OpenAIRE

    Nakane, Koji; OGATA, Nobuo

    2010-01-01

    Titanium oxide (TiO2) nanofibers were formed by calcination of poly(vinyl alcohol) (PVA)Ti lactate hybrid precursor nanofibers in air. The fiber diameters of the PVA-Ti lactate hybrid nanofibers were 200-350 nm, and the fiber diameters of the TiO2 nanofibers were 7080% of those of the PVA-Ti lactate hybrid nanofibers. The specific surface area and average pore diameter of the TiO2 nanofibers calcined at 500°C for 5 hours were 21.0 m2/g and 7.4 nm, respectively. TiO2 hollow-nanofibers (nanotub...

  12. Corrosion experience in calcination of liquid nuclear waste

    Energy Technology Data Exchange (ETDEWEB)

    Zimmerman, C A

    1980-01-01

    The Waste Calcining Facility (WCF) at the Idaho National Engineering Laboratory became operational in 1963. Since that time, approximately 13,337,137 litres (3,523,375 gallons) of liquid nuclear wastes, generated during the reprocessing of spent nuclear fuel materials, have been reduced to dry granular solids. The volume reduction is about seven or eight gallons of liquid waste to one gallon of dry granular solids. This paper covers some of the corrosion experiences encountered in over fifteen years of operating that calcination facility. 7 figures, 7 tables.

  13. Process Design Concepts for Stabilization of High Level Waste Calcine

    Energy Technology Data Exchange (ETDEWEB)

    T. R. Thomas; A. K. Herbst

    2005-06-01

    The current baseline assumption is that packaging ¡§as is¡¨ and direct disposal of high level waste (HLW) calcine in a Monitored Geologic Repository will be allowed. The fall back position is to develop a stabilized waste form for the HLW calcine, that will meet repository waste acceptance criteria currently in place, in case regulatory initiatives are unsuccessful. A decision between direct disposal or a stabilization alternative is anticipated by June 2006. The purposes of this Engineering Design File (EDF) are to provide a pre-conceptual design on three low temperature processes under development for stabilization of high level waste calcine (i.e., the grout, hydroceramic grout, and iron phosphate ceramic processes) and to support a down selection among the three candidates. The key assumptions for the pre-conceptual design assessment are that a) a waste treatment plant would operate over eight years for 200 days a year, b) a design processing rate of 3.67 m3/day or 4670 kg/day of HLW calcine would be needed, and c) the performance of waste form would remove the HLW calcine from the hazardous waste category, and d) the waste form loadings would range from about 21-25 wt% calcine. The conclusions of this EDF study are that: (a) To date, the grout formulation appears to be the best candidate stabilizer among the three being tested for HLW calcine and appears to be the easiest to mix, pour, and cure. (b) Only minor differences would exist between the process steps of the grout and hydroceramic grout stabilization processes. If temperature control of the mixer at about 80„aC is required, it would add a major level of complexity to the iron phosphate stabilization process. (c) It is too early in the development program to determine which stabilizer will produce the minimum amount of stabilized waste form for the entire HLW inventory, but the volume is assumed to be within the range of 12,250 to 14,470 m3. (d) The stacked vessel height of the hot process vessels

  14. Screening Level Risk Assessment for the New Waste Calcining Facility

    Energy Technology Data Exchange (ETDEWEB)

    M. L. Abbott; K. N. Keck; R. E. Schindler; R. L. VanHorn; N. L. Hampton; M. B. Heiser

    1999-05-01

    This screening level risk assessment evaluates potential adverse human health and ecological impacts resulting from continued operations of the calciner at the New Waste Calcining Facility (NWCF) at the Idaho Nuclear Technology and Engineering Center (INTEC), Idaho National Engineering and Environmental Laboratory (INEEL). The assessment was conducted in accordance with the Environmental Protection Agency (EPA) report, Guidance for Performing Screening Level Risk Analyses at Combustion Facilities Burning Hazardous Waste. This screening guidance is intended to give a conservative estimate of the potential risks to determine whether a more refined assessment is warranted. The NWCF uses a fluidized-bed combustor to solidify (calcine) liquid radioactive mixed waste from the INTEC Tank Farm facility. Calciner off volatilized metal species, trace organic compounds, and low-levels of radionuclides. Conservative stack emission rates were calculated based on maximum waste solution feed samples, conservative assumptions for off gas partitioning of metals and organics, stack gas sampling for mercury, and conservative measurements of contaminant removal (decontamination factors) in the off gas treatment system. Stack emissions were modeled using the ISC3 air dispersion model to predict maximum particulate and vapor air concentrations and ground deposition rates. Results demonstrate that NWCF emissions calculated from best-available process knowledge would result in maximum onsite and offsite health and ecological impacts that are less then EPA-established criteria for operation of a combustion facility.

  15. Method for calcining nuclear waste solutions containing zirconium and halides

    Science.gov (United States)

    Newby, Billie J.

    1979-01-01

    A reduction in the quantity of gelatinous solids which are formed in aqueous zirconium-fluoride nuclear reprocessing waste solutions by calcium nitrate added to suppress halide volatility during calcination of the solution while further suppressing chloride volatility is achieved by increasing the aluminum to fluoride mole ratio in the waste solution prior to adding the calcium nitrate.

  16. Effect of fly ash calcination in geopolymer synthesis

    Science.gov (United States)

    Samadhi, Tjokorde Walmiki; Jatiningrum, Mirna; Arisiani, Gresia

    2015-12-01

    Geopolymer, a largely amorphous class of inorganic polymer consisting of aluminosilicate repeat units, is an environmentally attractive engineering material due to its ability to consume aluminosilicate waste as raw materials. This work studies the effect of the calcination temperature of a coal fly ash generated by a low-efficiency boiler on the mechanical strength of geopolymer mortar synthesized using a mixture of the fly ash, potassium hydroxide as the alkali activator, and locally available sand as the filler aggregate. The calcination temperature is varied between 500-700 °C, with a calcination period of 2 hours in an electric furnace. Two sand samples with different particle size distributions are used. The key response variable is the compressive strength at room temperature, measured after curing at 80 °C for 7 and 14 days. Uncalcined ash, with a carbon content of approximately 31.0%, is not amenable for geopolymer synthesis. Analysis of experimental data using the ANOVA method for general factorial design identifies significant main effects for all three experimental variables. Two-way interactions are significant, except that between sand type and curing period. Higher calcination temperature significantly improves the strength of the mortar. However, the strength of the obtained geopolymer mortars are still significantly lower than that of ordinary Portland cement mortar.

  17. Ninth Processing Campaign in the Waste Calcining Facility

    International Nuclear Information System (INIS)

    This report discusses the Ninth (and final) Processing Campaign at the Waste Calcining Facility. Several processing interruptions were experienced during this campaign and the emphasis of this report is on process and equipment performance with operating problems and corrective actions discussed in detail

  18. KINETICS OF SORPTION OF FLUORIDE ON CALCINED MAGNESITE IN BATCH

    DEFF Research Database (Denmark)

    Singano, J. J.; Mashauri, D. A.; Mtalo, F. W.;

    1997-01-01

    A series of sorption of fluoride on calcined magnesite are obtained from thermostatic pH-chemostat and jar test experiments. The fluoride removal is observed not to start instantly, as normal, but after a lag time of up to ½ an hour of contact time. A model for sorption kinetics is developed, bas...

  19. Inductive classification of operating data from a fluidized bed calciner

    International Nuclear Information System (INIS)

    A process flowsheet expert system for a fluidized bed calciner which solidifies high-level radioactive liquid waste was developed from pilot-plant data using a commercial, inductive classification program. After initial classification of the data, the resulting rules were inspected and adjusted to match existing knowledge of process chemistry. The final expert system predicts performance of process flowsheets based upon the chemical composition of the calciner feed and has been successfully used to identify potential operational problems prior to calciner pilot-plant testing of new flowsheets and to provide starting parameters for pilot-plant tests. By using inductive classification techniques to develop the initial rules from the calciner pilot-plant data and using existing process knowledge to verify the accuracy of these rules, an effective expert system was developed with a minimum amount of effort. This method may be applied for developing expert systems for other processes where numerous operating data are available and only general process chemistry effects are known

  20. Restart plan for the prototype vertical denitration calciner

    Energy Technology Data Exchange (ETDEWEB)

    SUTTER, C.S.

    1999-09-01

    Testing activities on the Prototype Vertical Denitration Calciner at PFP were suspended in January 1997 due to the hold on fissile material handling in the facility. The Restart Plan will govern the transition of the test program from the completion of the activity based startup review; through equipment checkout and surrogate material runs; to resumption of the testing program and transition to unrestricted testing.

  1. Analytical comparison between unprepared and calcined magnetitum(Cishi)

    Institute of Scientific and Technical Information of China (English)

    LI Gang; JIN Tongshun; YOU Juan; WANG Lu; WU Qinan

    2007-01-01

    The phases, chemical composition, surface appearance,crystal size,specific surface and thermal behavior of the unprepared and calcined forms of the mineral Magnetitum(Cishi),used as Chinese traditional medicine,were characterized by using X-ray powder diffraction,scan electron microscopy,inductively coupled plasma-atomic emission spectometry(ICP)and thermogravimetrie(TG).The results indicated that after calcination the main phase Fe304 of the calcined Magnetitum(Duan Cishi)remained,while the Fe203 phase disappeared.The contents of the harmful chemical elements Cd and Pb were obviously reduced,while the crystal size increased from 24.5 to 35.7 nm and surface loosened.There were different TG curves for unprepared and calcined Magnetitum(Cishi)samples on heating.The former showed two weight-losing steps(at 367.9-422.1℃ and 568.8-594.1℃),and the latter only one.These results might serve as a base for quality evaluation of Magnetitum (Cishi).

  2. Method of processing liquid radioactive wastes by calcination and vitrification

    International Nuclear Information System (INIS)

    The original liquid radioactive waste is added to the radioactive waste calcinate and glass-forming additions. The said components are converted into a paste form which is proportioned in the melting furnace. Moisturising the mixture with liquid radioactive waste eliminates dust, avoids radionuclide volatility and has an additional advantage that more radioactive waste can be processed. (E.S.)

  3. Calcined Waste Storage at the Idaho Nuclear Technology and Engineering Center

    Energy Technology Data Exchange (ETDEWEB)

    M. D. Staiger

    2007-06-01

    This report provides a quantitative inventory and composition (chemical and radioactivity) of calcined waste stored at the Idaho Nuclear Technology and Engineering Center. From December 1963 through May 2000, liquid radioactive wastes generated by spent nuclear fuel reprocessing were converted into a solid, granular form called calcine. This report also contains a description of the calcine storage bins.

  4. Flash calcination of kaolinite rich clay and impact of process conditions on the quality of the calcines: A way to reduce CO2 footprint from cement industry

    DEFF Research Database (Denmark)

    Gebremariam, Abraham Teklay; Yin, Chungen; Rosendahl, Lasse

    2016-01-01

    Use of properly calcined kaolinite rich clay (i.e., metakaolin) to offset part of CO2-intensive clinkers not only reduces CO2 footprint from cement industry but also improves the performance of concrete. However, calcination under inappropriately high temperatures or long retention times may...... deplete metakaolin into unwanted products (e.g., mullite), which limits the use of the calcines as a supplementary cementitious material. With this regard, a dynamic model of flash calcination of kaolinite rich clay particles is developed using gPROMS (general PROcess Modeling System) to predict...... the impacts of calcination temperature and residence time on the transformation of the clay particles and to derive a favorable production path that is able to achieve optimum amount of the desired product. Flash calcination tests of the kaolinite rich clay particles are also performed in a pilot-scale gas...

  5. Isotopic Variability of Mercury in Ore, Mine-Waste Calcine, and Leachates of Mine-Waste Calcine from Areas Mined for Mercury

    OpenAIRE

    Stetson, Sarah J.; Gray, John E.; Wanty, Richard B.; Macalady, Donald L.

    2009-01-01

    The isotopic composition of mercury (Hg) was determined in cinnabar ore, mine-waste calcine (retorted ore), and leachates obtained from water leaching experiments of calcine from two large Hg mining districts in the U.S. This study is the first to report significant mass-dependent Hg isotopic fractionation between cinnabar ore and resultant calcine. Data indicate that δ202Hg values relative to NIST 3133 of calcine (up to 1.52‰) in the Terlingua district, Texas, are as much as 3.24‰ heavier th...

  6. Pollution and Prevention of Pb during Cement Calcination

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Emission pollution and prevention measures of Pb during cement calcination were discussed. The content of Pb and the variation of composition were explored by means of atomic absorption spectroscopy (AAS) and X-ray diffraction. The results show that a number of Pb emits during cement calcination, F and C1 promote the emission of Pb, and Pb is enriched in kiln dust. The smaller the particle of kiln dust, the higher the content of Pb. When utilizing the raw materials with a high content of Pb, a more efficient dust collector should be used and the kiln dust should be used as the addition of cement. Pb in clinker is enriched in the intermediate phase. The reduction of silica modulus is useful to increase the solidification content of Pb in clinker. The solidification content of Pb in calcium sulphoaluminate mineral is higher than that in calcium aluminate mineral.

  7. Calcined sodium silicate as solid base catalyst for biodiesel production

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Feng; Peng, Zhen-Gang; Dai, Jian-Ying; Xiu, Zhi-Long [Department of Bioscience and Biotechnology, School of Environmental and Biological Science and Technology, Dalian University of Technology, Dalian 116024 (China)

    2010-03-15

    This paper examined the use of calcined sodium silicate as a novel solid base catalyst in the transesterification of soybean oil with methanol. The calcined sodium silicate was characterized by DTA-TG, Hammett indicator method, XRD, SEM, BET, IR and FT-IR. It catalyzed the transesterification of soybean oil to biodiesel with a yield of almost 100% under the following conditions: sodium silicate of 3.0 wt.%, a molar ratio of methanol/oil of 7.5:1, reaction time of 60 min, reaction temperature of 60 C, and stirring rate of 250 rpm. The oil containing 4.0 wt.% water or 2.5 wt.% FFA could also be transesterified by using this catalyst. The catalyst can be reused for at least 5 cycles without loss of activity. (author)

  8. Calcining process emission screening test for polychlorinated dibenzodioxins

    International Nuclear Information System (INIS)

    Since 1963, the Idaho Chemical Processing Plant (ICPP) at the Idaho National Engineering Laboratory has been using fluidized-bed technology to convert high-level radioactive liquid waste into a granular solid for interim storage before eventual long-term storage. The calcining process uses kerosene, oxygen, air and a cooling jacket to maintain the temperature of the fluidized bed at approximately 400 C. The solids are moved to storage bins and the combustion gases and fine particles are swept from the bed to an atmospheric protection system. This atmospheric protection system includes a cyclone to collect larger particles; a nitric acid scrubber to cool gases and collect small particles; a condenser to reduce water content; silica gel beds to adsorb volatile ruthenium, water, and hydrocarbons; and a series of high efficiency particulate air (HEPA) filters to collect minute particles. The calcination process solidifies waste solutions containing molar levels of acid, nitrate, fluoride, zirconium, aluminum, iron, boron, and cadmium; minor levels (<0.1%) of various fission products and organics; and trace levels (<50 ppm) of chloride and sulfate. Because the process burns kerosene in the presence of other organics and chloride salts; the calciner was considered a potential production source of polychlorinated dibenzo-p-dioxins (PCDD). Therefore, it was necessary to determine if PCDD were being released from the calcination process. Because a gas chromatograph mass spectrometer (GC-MS) and PCDD standards were not available, a screening procedure using two gas chromatographs with electron capture detectors and no PCDD calibration standards was developed

  9. Calcining process emission screening test for polychlorinated dibenzodioxins

    Energy Technology Data Exchange (ETDEWEB)

    Hartenstein, S.D.

    1993-08-01

    Since 1963, the Idaho Chemical Processing Plant (ICPP) at the Idaho National Engineering Laboratory has been using fluidized-bed technology to convert high-level radioactive liquid waste into a granular solid for interim storage before eventual long-term storage. The calcining process uses kerosene, oxygen, air and a cooling jacket to maintain the temperature of the fluidized bed at approximately 400 C. The solids are moved to storage bins and the combustion gases and fine particles are swept from the bed to an atmospheric protection system. This atmospheric protection system includes a cyclone to collect larger particles; a nitric acid scrubber to cool gases and collect small particles; a condenser to reduce water content; silica gel beds to adsorb volatile ruthenium, water, and hydrocarbons; and a series of high efficiency particulate air (HEPA) filters to collect minute particles. The calcination process solidifies waste solutions containing molar levels of acid, nitrate, fluoride, zirconium, aluminum, iron, boron, and cadmium; minor levels (<0.1%) of various fission products and organics; and trace levels (<50 ppm) of chloride and sulfate. Because the process burns kerosene in the presence of other organics and chloride salts; the calciner was considered a potential production source of polychlorinated dibenzo-p-dioxins (PCDD). Therefore, it was necessary to determine if PCDD were being released from the calcination process. Because a gas chromatograph mass spectrometer (GC-MS) and PCDD standards were not available, a screening procedure using two gas chromatographs with electron capture detectors and no PCDD calibration standards was developed.

  10. Mathematical modeling of a rotary hearth coke calciner

    OpenAIRE

    Hilde C. Meisingset; Jens G. Balchen

    1995-01-01

    A mathematical model of a rotary hearth coke calciner is developed. The model is based on first principles including the most important dynamic phenomena. The model is a thermodynamic model involving heat and mass transfer and chemical reactions. Fundamental mass and energy balance equations for the coke phase, the gas phase and the lining are formulated. For the gas phase, a stationary model is used. The equations are solved numerically, and simulated temperature profiles are shown in this p...

  11. Apatite formation on calcined kaolin-white Portland cement geopolymer

    OpenAIRE

    Pangdaeng, S.; Sata, V.; Aguiar, J. L. Barroso de; Torgal, Fernando Pacheco; Chindaprasirt, P.

    2015-01-01

    In this study, calcined kaolin–white Portland cement geopolymerwas investigated for use as biomaterial. Sodiumhydroxide and sodium silicate were used as activators. In vitro test was performed with simulated body fluid (SBF) for bioactivity characterization. The formation of hydroxyapatite bio-layer on the 28-day soaked samples surface was tested using SEM, EDS and XRD analyses. The results showed that the morphology of hydroxyapatite was affected by the source material composition, alkali co...

  12. Mathematical modeling of a rotary hearth coke calciner

    Directory of Open Access Journals (Sweden)

    Hilde C. Meisingset

    1995-10-01

    Full Text Available A mathematical model of a rotary hearth coke calciner is developed. The model is based on first principles including the most important dynamic phenomena. The model is a thermodynamic model involving heat and mass transfer and chemical reactions. Fundamental mass and energy balance equations for the coke phase, the gas phase and the lining are formulated. For the gas phase, a stationary model is used. The equations are solved numerically, and simulated temperature profiles are shown in this paper.

  13. Atmospheric pressure plasma assisted calcination of composite submicron fibers

    Science.gov (United States)

    Medvecká, Veronika; Kováčik, Dušan; Tučeková, Zlata; Zahoranová, Anna; Černák, Mirko

    2016-08-01

    The plasma assisted calcination of composite organic/inorganic submicron fibers for the preparation of inorganic fibers in submicron scale was studied. Aluminium butoxide/polyvinylpyrrolidone fibers prepared by electrospinning were treated using low-temperature plasma generated by special type of dielectric barrier discharge, so called diffuse coplanar surface barrier discharge (DCSBD) at atmospheric pressure in ambient air, synthetic air, oxygen and nitrogen. Effect of plasma treatment on base polymer removal was investigated by using Attenuated total reflectance - Fourier transform infrared (ATR-FTIR) spectroscopy. Influence of working gas on the base polymer reduction was studied by energy-dispersive X-ray spectroscopy (EDX) and CHNS elemental analysis. Changes in fibers morphology were observed by scanning electron microscopy (SEM). High efficiency of organic template removal without any degradation of fibers was observed after plasma treatment in ambient air. Due to the low-temperature approach and short exposure time, the plasma assisted calcination is a promising alternative to the conventional thermal calcination. Contribution to the topical issue "6th Central European Symposium on Plasma Chemistry (CESPC-6)", edited by Nicolas Gherardi, Ester Marotta and Cristina Paradisi

  14. Addendum to the Calcined Waste Storage at the Idaho Nuclear Technology Center

    Energy Technology Data Exchange (ETDEWEB)

    M. D. Staiger; Michael Swenson; T. R. Thomas

    2004-05-01

    This report is an addendum to the report Calcined Waste Storage at the Idaho Nuclear Technology and Engineering Center, INEEL/EXT-98-00455 Rev. 1, June 2003. The original report provided a summary description of the Calcined Solids Storage Facilities (CSSFs). It also contained dozens of pages of detailed data tables documenting the volume and composition (chemical content and radionuclide activity) of the calcine stored in the CSSFs and the liquid waste from which the calcine was derived. This addendum report compiles the calcine composition data from the original report. It presents the compiled data in a graphical format with units (weight percent, curies per cubic meter, and nanocuries per gram) that are commonly used in regulatory and waste acceptance criteria documents. The compiled data are easier to use and understand when comparing the composition of the calcine with potential regulatory or waste acceptance criteria. This addendum report also provides detailed explanations for the large variability in the calcine composition among the CSSFs. The calcine composition varies as a result of reprocessing different types of fuel that had different cladding materials. Different chemicals were used to dissolve the various types of fuel, extract the uranium, and calcine the resulting waste. This resulted in calcine with variable compositions. This addendum report also identifies a few trace chemicals and radionuclides for which the accuracy of the amounts estimated to be in the calcine could be improved by making adjustments to the assumptions and methods used in making the estimates.

  15. Literature Review of Puo2 Calcination Time and Temperature Data for Specific Surface Area

    International Nuclear Information System (INIS)

    The literature has been reviewed in December 2011 for calcination data of plutonium oxide (PuO2) from plutonium oxalate Pu(C2O4)2 precipitation with respect to the PuO2 specific surface area (SSA). A summary of the literature is presented for what are believed to be the dominant factors influencing SSA, the calcination temperature and time. The PuO2 from Pu(C2O4)2 calcination data from this review has been regressed to better understand the influence of calcination temperature and time on SSA. Based on this literature review data set, calcination temperature has a bigger impact on SSA versus time. However, there is still some variance in this data set that may be reflecting differences in the plutonium oxalate preparation or different calcination techniques. It is evident from this review that additional calcination temperature and time data for PuO2 from Pu(C2O4)2 needs to be collected and evaluated to better define the relationship. The existing data set has a lot of calcination times that are about 2 hours and therefore may be underestimating the impact of heating time on SSA. SRNL recommends that more calcination temperature and time data for PuO2 from Pu(C2O4)2 be collected and this literature review data set be augmented to better refine the relationship between PuO2 SSA and its calcination parameters.

  16. ICPP radioactive liquid and calcine waste technologies evaluation. Interim report

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, J.A.; Pincock, L.F.; Christiansen, I.N.

    1994-06-01

    The Department of Energy (DOE) has received spent nuclear fuel (SNF) at the Idaho Chemical Processing Plant (ICPP) for interim storage since 1951 and reprocessing since 1953. Until recently, the major activity of the ICPP has been the reprocessing of SNF to recover fissile uranium; however, changing world events have raised questions concerning the need to recover and recycle this material. In April 1992, DOE chose to discontinue reprocessing SNF for uranium recovery and shifted its focus toward the management and disposition of radioactive wastes accumulated through reprocessing activities. Currently, 1.8 million gallons of radioactive liquid wastes (1.5 million gallons of radioactive sodium-bearing liquid wastes and 0.3 million gallons of high-level liquid waste) and 3,800 cubic meters (m{sup 3}) of calcine waste are in inventory at the ICPP. Legal drivers and agreements exist obligating the INEL to develop, demonstrate, and implement technologies for safe and environmentally sound treatment and interim storage of radioactive liquid and calcine waste. Candidate treatment processes and waste forms are being evaluated using the Technology Evaluation and Analysis Methodology (TEAM) Model. This process allows decision makers to (1) identify optimum radioactive waste treatment and disposal form alternatives; (2) assess tradeoffs between various optimization criteria; (3) identify uncertainties in performance parameters; and (4) focus development efforts on options that best satisfy stakeholder concerns. The Systems Analysis technology evaluation presented in this document supports the DOE in selecting the most effective radioactive liquid and calcine waste management plan to implement in compliance with established regulations, court orders, and agreements.

  17. Retrieval System for Calcined Waste for the Idaho Cleanup Project - 12104

    International Nuclear Information System (INIS)

    This paper describes the conceptual approach to retrieve radioactive calcine waste, hereafter called calcine, from stainless steel storage bins contained within concrete vaults. The retrieval system will allow evacuation of the granular solids (calcine) from the storage bins through the use of stationary vacuum nozzles. The nozzles will use air jets for calcine fluidization and will be able to rotate and direct the fluidization or displacement of the calcine within the bin. Each bin will have a single retrieval system installed prior to operation to prevent worker exposure to the high radiation fields. The addition of an articulated camera arm will allow for operations monitoring and will be equipped with contingency tools to aid in calcine removal. Possible challenges (calcine bridging and rat-holing) associated with calcine retrieval and transport, including potential solutions for bin pressurization, calcine fluidization and waste confinement, are also addressed. The Calcine Disposition Project has the responsibility to retrieve, treat, and package HLW calcine. The calcine retrieval system has been designed to incorporate the functions and technical characteristics as established by the retrieval system functional analysis. By adequately implementing the highest ranking technical characteristics into the design of the retrieval system, the system will be able to satisfy the functional requirements. The retrieval system conceptual design provides the means for removing bulk calcine from the bins of the CSSF vaults. Top-down vacuum retrieval coupled with an articulating camera arm will allow for a robust, contained process capable of evacuating bulk calcine from bins and transporting it to the processing facility. The system is designed to fluidize, vacuum, transport and direct the calcine from its current location to the CSSF roof-top transport lines. An articulating camera arm, deployed through an adjacent access riser, will work in conjunction with the

  18. 46 CFR 148.04-17 - Petroleum coke, calcined, at 130 °F or above.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Petroleum coke, calcined, at 130 °F or above. 148.04-17...-17 Petroleum coke, calcined, at 130 °F or above. (a) The requirements of this part do not apply to bulk shipments of petroleum coke, calcined, on any vessel when the material is less than 130 °F....

  19. Fluidized-bed calcination of simulated commercial high-level radioactive wastes

    International Nuclear Information System (INIS)

    Work is in progress at the Idaho Chemical Processing Plant to verify process flowsheets for converting simulated commercial high-level liquid wastes to granular solids using the fluidized-bed calcination process. Primary emphasis in the series of runs reported was to define flowsheets for calcining simulated Allied-General Nuclear Services (AGNS) waste and to evaluate product properties significant to calcination, solids storage, or post treatment. Pilot-plant studies using simulated high-level acid wastes representative of those to be produced by Nuclear Fuel Services, Inc. (NFS) are also included. Combined AGNS high-level and intermediate-level waste (0.26 M Na in blend) was successfully calcined when powdered iron was added (to result in a Na/Fe mole ratio of 1.0) to the feed to prevent particle agglomeration due to sodium nitrate. Long-term runs (approximately 100 hours) showed that calcination of the combined waste is practical. Concentrated AGNS waste containing sodium at concentrations less than 0.2 M were calcined successfully; concentrated waste containing 1.13 M Na calcined successfully when powdered iron was added to the feed to suppress sodium nitrate formation. Calcination of dilute AGNS waste by conventional fluid-bed techniques was unsuccessful due to the inability to control bed particle size--both particle size and bed level decreased. Fluid-bed solidification of AGNS dilute waste at conditions in which most of the calcined solids left the calciner vessel with the off-gas was successful. In such a concept, the steady-state composition of the bed material would be approximately 22 wt percent calcined solids deposited on inert particles. Calcination of simulated NFS acid waste indicated that solidification by the fluid-bed process is feasible

  20. Feasibility of Carbonaceous Nanomaterial-Assisted Photocatalysts Calcined at Different Temperatures for Indoor Air Applications

    Directory of Open Access Journals (Sweden)

    Wan-Kuen Jo

    2012-01-01

    Full Text Available This study examined the characteristics and photocatalytic activity of multiwall carbon nanotube-assisted TiO2 (MWNT-TiO2 nanocomposites calcined at different temperatures to assess their potential indoor air applications. It was confirmed that the composites calcined at low temperatures (300 and 400°C contained TiO2 nanoparticles bound intimately to the MWNT networks. Meanwhile, almost no MWNTs were observed when the calcination temperature was increased to 500 and 600°C. The MWNT-TiO2 composites calcined at low temperatures showed higher photocatalytic decomposition efficiencies for aromatic hydrocarbons at indoor concentrations than those calcined at high temperatures. The mean efficiencies for benzene, toluene, ethyl benzene, and o-xylene (BTEX by the composite calcined at 300°C were 32, 70, 79, and 79%, respectively, whereas they were 33, 71, 78, and 78% for the composite calcined at 400°C, respectively. In contrast, the efficiencies decreased to close to zero when the calcination temperature was increased to 600°C. Moreover, the MWNT-TiO2 exhibited superior photocatalytic performance for the decomposition efficiencies compared to TiO2 under conventional UV-lamp irradiations. Consequently, these carbonaceous nanomaterial-assisted photocatalysts can be applied effectively to indoor air applications depending upon the calcination temperature.

  1. STUDY ON HIGH ACID LEACHING REACTIVE CALCINED KAOLIN

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Leaching experiments on metakaolin show that the final Al extraction ratio reached in a batch reaction is strikingly influenced by the inferior pore structure geometry of the metakaolin pellets. By calcining kaolin particles adhered in low humidity state,a variety of metakaolin pellet,inside which a large openings structure developed,has been prepared. The structure remarkably benefits leachant ion transference,so,the variety has high acid leaching reactivity,even coarse as the pellets are,its aluminum extracted ratio still has a linear relationship with leaching time,and the leaching kinetics is maintained zero order up to a significant conversion degree. A revised Pellet-Particle Model has been developed to interpret the structure influence on Al extraction ratio.

  2. Ignition Dynamic Parameters for Coke in Cement Calciners

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The mathematical ignition model was established and researches of ignition dynamic parameters for coke in some typical coal samples from cement plants was carried out according to circumstances of coal combusted in cement plants.In order to get the ignitioin temperature Tpi of carbon particles more accurately,the temperature rising experimental method was used and the actual heating circumstances for pulverized coal in calciners(in cement plants)were also considered.With this method,the accurate determination of the ignition temperature of coke in coal was achieved,so as to get some ignition dynamic parameters.These research results provide a theoretical basis for investigating coal ignition characteristics more scientifically and more accurately.

  3. Model of fragmentation of limestone particles during thermal shock and calcination in fluidised beds

    Energy Technology Data Exchange (ETDEWEB)

    Saastamoinen, J.; Pikkarainen, T.; Tourunen, A.; Rasanen, M.; Jantti, T. [VTT Technical Research Center, Jyvaskyla (Finland)

    2008-11-15

    Fragmentation of limestone due to thermal shock and calcination in a fluidised bed was studied through experiments and modelling. The time for heating was estimated by model calculations and the time for calcination by measurements. Fragmentation due to thermal shock was carried out by experiments in a CO{sub 2} atmosphere in order to prevent the effect of calcination. It was found to be much less than fragmentation due to calcination. Average particle sizes before and after fragmentation are presented for several types of limestone. The effects of particle size and gas composition on the primary fragmentation were studied through experiments. Increasing the fluidisation velocity increased the tendency to fragment. The evolution of the particle size distribution (PSD) of limestone particles due to thermal shock and during calcination (or simultaneous calcination and sulphation) were calculated using a population balance model. Fragmentation due to thermal shock is treated as an instantaneous process. The fragmentation frequency during calcination is presented as exponentially decaying over time. In addition to the final PSD, this model also predicts the PSD during the calcination process. The fragmentation was practically found to end after 10 min. Furthermore. a population balance method to calculate the particle size distribution and amount of limestone in fluidised beds in dynamic and steady state, when feeding history is known, is presented.

  4. Effect of calcination temperature on the photocatalytic reduction and oxidation processes of hydrothermally synthesized titania nanotubes.

    Energy Technology Data Exchange (ETDEWEB)

    Viayan, B.; Dimitrijevic, N. M.; Rajh, T.; Gray, K.; Northwestern Univ.

    2010-08-05

    Titania nanotubes having diameters 8 to 12 nm and lengths of 50-300 nm were prepared using a hydrothermal method. Further, the titania nanotubes were calcined over the temperature range 200-800 C in order to enhance their photocatalytic properties by altering their morphology. The calcined titania nanotubes were characterized by using X-ray diffraction and surface area analysis and their morphological features were studied by scanning and transmission electron microscopy. Nanotubes calcined at 400 C showed the maximum extent of photocatalyitc reduction of carbon dioxide to methane, whereas samples calcined at 600 C produced maximum photocatalytic oxidation of acetaldehyde. Electron paramagnetic resonance (EPR) spectroscopy was used to interrogate the effects of nanotube structure on the charge separation and trapping as a function of calcination temperature. EPR results indicated that undercoordinated titania sites are associated with maximum CO{sub 2} reduction occurring in nanotubes calcined at 400 C. Despite the collapse of the nantube structure to form nanorods and the concomitant loss of surface area, the enhanced charge separation associated with increased crystallinity promoted high rates of oxidation of acetaldehyde in titania materials calcined at 600 C. These results illustrate that calcination temperature allows us to tune the morphological and surface features of the titania nanostructures for particular photocatalytic reactions.

  5. Calcination effects on CeZrOx geometry and styrene production from ethylbenzene

    NARCIS (Netherlands)

    Kovacevic, M.; Brunet Espinosa, R.; Lefferts, L.; Mojet, B.L.

    2014-01-01

    A series of CeZrOx catalysts was prepared by calcination of hydrothermally obtained metal oxide precipitate at increasing temperatures. The samples were characterized by HRSEM, XRD and Raman spectroscopy, showing a change in morphology and particle size as a function of calcination temperature. Cata

  6. Processing of Spent Ion Exchange Resins in a Rotary Calciner - 12212

    Energy Technology Data Exchange (ETDEWEB)

    Kascheev, Vladimir; Musatov, Nikolay [Joint Stock Company ' A.A. Bochvar High-Technology Scientific Research Institute of Inorganic Materials' (VNIINM), Rogova st., 5A (Russian Federation)

    2012-07-01

    Processing Russian nuclear ion exchange resin KU-2 using a 'Rotary' calciner was conducted. The resulting product is a dry free flowing powder (moisture content 3 wt.%, Angle of repose of ≅ 20 deg.). Compared with the original exchange resin the volume of the final product is about 3 times less.. Rotary calciner product can be stored in metal drums or in special reinforced concrete cubicles. After thermal treatment in a rotary calciner, the spent resin product can be solidified in cement yielding the following attributes: - The cemented waste is only a 35% increase over the volume of powder product; - The volume of cement calciner product is almost 9 times less (8.7) than the volume of cement solidified resin; - The mechanical strength of cemented calciner product meets the radioactive waste regulations in Russia. (authors)

  7. Modeling of in-line low-NOx calciners - a parametric study

    DEFF Research Database (Denmark)

    Iliuta, Ion; Dam-Johansen, Kim; Jensen, Anker;

    2002-01-01

    Simulations with a heterogeneous model of an in-line low-NOx calciner, based on non-isothermal diffusion-reaction models for char combustion and limestone calcination combined with a kinetic model for NO formation and reduction, are reported. The analysis shows that the most important hydrodynamic...... parameter is the mixing rate of preheated combustion air into the sub-stoichiometric suspension leaving the reducing zone and the most important combustion parameter is the char reactivity. Also, the calcination rate modifies very much the temperature in the calciner, char and limestone conversion...... and NO emission. Carbon monoxide is a key component for the reduction of NO and reliable data for the kinetics of NO reduction by CO over CaO are very important for the prediction of the NO emission. The internal surface area of char and limestone particles influences the combustion and calcination rates...

  8. LITERATURE REVIEW OF PUO2 CALCINATION TIME AND TEMPERATURE DATA FOR SPECIFIC SURFACE AREA

    Energy Technology Data Exchange (ETDEWEB)

    Daniel, G.

    2012-03-06

    The literature has been reviewed in December 2011 for calcination data of plutonium oxide (PuO{sub 2}) from plutonium oxalate Pu(C{sub 2}O{sub 4}){sub 2} precipitation with respect to the PuO{sub 2} specific surface area (SSA). A summary of the literature is presented for what are believed to be the dominant factors influencing SSA, the calcination temperature and time. The PuO{sub 2} from Pu(C{sub 2}O{sub 4}){sub 2} calcination data from this review has been regressed to better understand the influence of calcination temperature and time on SSA. Based on this literature review data set, calcination temperature has a bigger impact on SSA versus time. However, there is still some variance in this data set that may be reflecting differences in the plutonium oxalate preparation or different calcination techniques. It is evident from this review that additional calcination temperature and time data for PuO{sub 2} from Pu(C{sub 2}O{sub 4}){sub 2} needs to be collected and evaluated to better define the relationship. The existing data set has a lot of calcination times that are about 2 hours and therefore may be underestimating the impact of heating time on SSA. SRNL recommends that more calcination temperature and time data for PuO{sub 2} from Pu(C{sub 2}O{sub 4}){sub 2} be collected and this literature review data set be augmented to better refine the relationship between PuO{sub 2} SSA and its calcination parameters.

  9. CFD Modelling and Experimental Testing of Thermal Calcination of Kaolinite Rich Clay Particles - An Effort towards Green Concrete

    DEFF Research Database (Denmark)

    Gebremariam, Abraham Teklay

    calciner (GSC), and to characterize the calcines obtained under different calcination conditions, which are either provided to the numerical model as inputs or as database for model validation. The model is able to reliably predict the temperature and residence time at which a given clay material attains...

  10. Synthesis of porous superparamagnetic iron oxides from colloidal nanoparticles: Effect of calcination temperature and atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Wei; Xu, Jing; Ding, Wei; Wang, Yajie; Zheng, Wenping; Wu, Feng; Li, Jinjun, E-mail: ljjcbacademy@163.com

    2015-03-01

    Nanostructured iron oxides with superparamagnetism were synthesized from colloidal particles of hydrous iron oxide. The synthesis procedure involved preparation of acetone-nanoparticle composite and calcination of the composite in air or nitrogen. The effects of calcination temperature and atmosphere on the properties of the products were investigated. Powder X-ray diffraction, {sup 57}Fe Mössbauer spectra, transmission electron microscopy, nitrogen sorption, thermal analysis and vibrating-sample magnetometry were applied to characterize the materials. The products calcined in flowing air are composed of nanoparticles, while those calcined in flowing nitrogen contain nanosheets. The former has larger specific surface areas, whereas the latter has stronger saturation magnetization in external magnetic field. Increasing calcination temperature reduced the specific surface area of the product, whereas enhanced its saturation magnetization. Furthermore, the iron oxides with superparamagnetism showed good affinity to arsenite, and therefore they could be potential adsorbents for arsenic remediation in water. - Highlights: • Nanostructured superparamagnetic iron oxides were synthesized from colloidal nanoparticles. • Calcination in air led to formation of nanoparticles. • Calcination in nitrogen led to formation of nanosheets. • The superparamagnetic materials had high adsorption capabilities for arsenite.

  11. Pyrochemical separation of radioactive components from inert materials in ICPP high-level calcined waste

    Energy Technology Data Exchange (ETDEWEB)

    Del Debbio, J.A.; Nelson, L.O.; Todd, T.A.

    1995-05-01

    Since 1963, calcination of aqueous wastes from reprocessing of DOE-owned spent nuclear fuels has resulted in the accumulation of approximately 3800 m{sup 3} of high-level waste (HLW) at the Idaho Chemical Processing Plant (ICPP). The waste is in the form of a granular solid called calcine and is stored on site in stainless steel bins which are encased in concrete. Due to the leachability of {sup 137}Cs and {sup 90}Sr and possibly other radioactive components, the calcine is not suitable for final disposal. Hence, a process to immobilize calcine in glass is being developed. Since radioactive components represent less than 1 wt % of the calcine, separation of actinides and fission products from inert components is being considered to reduce the volume of HLW requiring final disposal. Current estimates indicate that compared to direct vitrification, a volume reduction factor of 10 could result in significant cost savings. Aqueous processes, which involve calcine dissolution in nitric acid followed by separation of actinide and fission products by solvent extraction and ion exchange methods, are being developed. Pyrochemical separation methods, which generate small volumes of aqueous wastes and do not require calcine dissolution, have been evaluated as alternatives to aqueous processes. This report describes three proposed pyrochemical flowsheets and presents the results of experimental studies conducted to evaluate their feasibility. The information presented is a consolidation of three reports, which should be consulted for experimental details.

  12. A Real-Time Mathematical Model for the Two-Dimensional Temperature Field of Petroleum Coke Calcination in Vertical Shaft Calciner

    Science.gov (United States)

    Xiao, Jin; Huang, Jindi; Zhong, Qifan; Li, Fachuang; Zhang, Hongliang; Li, Jie

    2016-08-01

    A real-time mathematical model for the two-dimensional temperature field of petroleum coke calcination in vertical shaft calciner was developed based on computational fluid dynamics. In the modeling process, the petroleum coke discharging process was described by the solid viscous flow, the dynamic heat flux boundary condition was adopted to specify the heat transfer between the flue wall and the gas in the flue, and the Arrhenius equation was used to characterize the pyrolysis process of petroleum coke. The model was validated with both measurement data and data from the literature. The effects of discharge rate per pot, volatile content of green coke, and excess air coefficient on the temperature field of the vertical shaft calciner were investigated with the use of the developed model. The following reasonable operating conditions were obtained: the discharge rate per pot should be less than 90 kg/h, the volatile content of green coke should be in the range of 9-11%, and the excess air coefficient should be in the range of 1.10-1.20. In this work, the governing equations were discretized by using the finite volume method, and the discrete linear equations were solved by using sparse matrix package UMFPACK. The model calculating process takes about less than 15 s. Therefore, the model is beneficial in realizing real-time online temperature detection of petroleum coke calcination in a vertical shaft calciner.

  13. A Real-Time Mathematical Model for the Two-Dimensional Temperature Field of Petroleum Coke Calcination in Vertical Shaft Calciner

    Science.gov (United States)

    Xiao, Jin; Huang, Jindi; Zhong, Qifan; Li, Fachuang; Zhang, Hongliang; Li, Jie

    2016-02-01

    A real-time mathematical model for the two-dimensional temperature field of petroleum coke calcination in vertical shaft calciner was developed based on computational fluid dynamics. In the modeling process, the petroleum coke discharging process was described by the solid viscous flow, the dynamic heat flux boundary condition was adopted to specify the heat transfer between the flue wall and the gas in the flue, and the Arrhenius equation was used to characterize the pyrolysis process of petroleum coke. The model was validated with both measurement data and data from the literature. The effects of discharge rate per pot, volatile content of green coke, and excess air coefficient on the temperature field of the vertical shaft calciner were investigated with the use of the developed model. The following reasonable operating conditions were obtained: the discharge rate per pot should be less than 90 kg/h, the volatile content of green coke should be in the range of 9-11%, and the excess air coefficient should be in the range of 1.10-1.20. In this work, the governing equations were discretized by using the finite volume method, and the discrete linear equations were solved by using sparse matrix package UMFPACK. The model calculating process takes about less than 15 s. Therefore, the model is beneficial in realizing real-time online temperature detection of petroleum coke calcination in a vertical shaft calciner.

  14. Calcination/dissolution chemistry development Fiscal year 1995

    Energy Technology Data Exchange (ETDEWEB)

    Delegard, C.H.

    1995-09-01

    The task {open_quotes}IPC Liaison and Chemistry of Thermal Reconstitution{close_quotes} is a $300,000 program that was conducted in Fiscal Year (FY) 1995 with U.S. Department of Energy (DOE) Office of Research and Development (EM-53) Efficient Separations and Processing Crosscutting Program supported under technical task plan (TTP) RL4-3-20-04. The principal investigator was Cal Delegard of the Westinghouse Hanford Company (WHC). The task encompassed the following two subtasks related to the chemistry of alkaline Hanford Site tank waste: (1) Technical Liaison with the Institute of Physical Chemistry of the Russian Academy of Science (IPC/RAS) and its research into the chemistry of transuranic elements (TRU) and technetium (Tc) in alkaline media. (2) Laboratory investigation of the chemistry of calcination/dissolution (C/D) (or thermal reconstitution) as an alternative to the present reference Hanford Site tank waste pretreatment flowsheet, Enhanced Sludge Washing (ESW). This report fulfills the milestone for the C/D subtask to {open_quotes}Provide End-of-Year Report on C/D Laboratory Test Results{close_quotes} due 30 September 1995. A companion report, fulfilling the milestone to provide an end-of-year report on the IPC/RAS liaison, also has been prepared.

  15. Immobilization of Penicillin G Acylase on Calcined Layered Double Hydroxides

    Institute of Scientific and Technical Information of China (English)

    REN Ling-ling; HE Jing; Evans D. G.; DUAN Xue

    2003-01-01

    A hydrotalcite-like Mg2+/Al3+ layered double hydroxide(LDH) material was prepared by means of a modified coprecipitation method involving a rapid mixing step followed by a separate aging process. LDH calcined at 500 ℃, denoted as CLDH, was characterized by XRD, IR and BET surface area measurements. CLDH has a poor crystalline MgO-like structure with a high surface area and porosity. CLDH was used as a support for the immobilization of penicillin G acylase(PGA). The effect of varying the immobilization conditions, such as pH, contact time and the ratio of enzyme to support, on the activity of the immobilized enzyme in the hydrolysis of penicillin G has been studied. It was found that the activity of the immobilized enzyme decreased slightly with decreasing pH and reached a maximum after a contact time of 24 h. The activity of the immobilized enzyme increased with increasing the ratio of enzyme to support. It was found that the adsorption of PGA inhibited the expected reaction of CLDH with an aqueous medium to regenerate a LDH phase. Its original activity(36%) after 15 cycles of reuse of the immobilized enzyme was retained, but no further loss in the activity was observed.

  16. Effect of calcination temperature on structural and magnetic properties of nanocrystalline magnesium ferrite powders

    Science.gov (United States)

    Sumangala, T. P.; Mahender, C.; Venkataramani, N.; Prasad, S.

    2013-02-01

    MgFe2O4 powders with nanosize (30 - 100 nm) were synthesized by the solgel auto combustion method. These powders were calcined at various temperatures (300°C, 400°C, 500°C, 600°C, 700°C, 800°C). An increase in particle size was observed as a function of calcination temperature. The appearance of α-Fe2O3 in samples calcined at intermediate temperatures was studied by XRD, Raman spectra and was confirmed using magnetization data.

  17. Mathematical modeling of an in-line low-NOx calciner

    DEFF Research Database (Denmark)

    Iliuta, Ion; Dam-Johansen, Kim; Jensen, Lars Skaarup

    2002-01-01

    The reduction of the NOx content in in-line-calciner-type kiln systems can be made by optimization of the primary filing in the rotary kiln and of the secondary firing in the calciner. Because the optimization of calciner offers greater opportunities the mathematical modeling of this reactor...... and the temperature profile. The mixing rate has some influence on the CO concentration profile and an important influence on the overall degree of fuel-N to NO conversion. (C) 2002 Elsevier Science Ltd. All rights reserved....

  18. Mechanism of Calcined Phosphogypsum for the Volume Change of Blended Cement

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The paper describes an investigation into the volume change of cement mortar specimen at the three kinds of different curing schedules including 20℃ and 5% Na2SO4 solution curing, tap water standard curing, 50% RH curing for 90 days. The testing results of hydration heat, chemical shrinking and XRD prove that calcined phosphogypsum has evident excitation effect on the activity of high calcium ash and steel slag. Simultaneously, calcined phosphogypsum has the function of decreasing volume shrinkage to blended cement possessing steel slag and high calcium ash. In sulfate curing, calcined phosphogypsum can avoid the phenomenon of protrude apex of the blended cement.

  19. Effect of Heat Treatment Temperature on Properties of Chinese Calcined Flint Clay Based Plastic Refractories

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wei; DAI Wenyong; YU Xinfeng; LI Liang

    2009-01-01

    Effects of different heat treatment temperatures on properties of Chinese calcined flint clay based plastic refractories were investigated using Chinese calcined flint clay as starting material,aluminum sulfate and fireclay as binding system.The results showed that with temperature rising,Chinese calcined flint clay based plastic refractories shrinked firstly and then expanded.The modulus of rupture (MOR) and the cold crushing strength (CCS) increased firstly and then decreased from 110 ℃ to 600 ℃,then increased obviously.Thermal expansion coefficient increased from 110 ℃ to 760 ℃,decreased from 760 ℃ to 1 300 ℃,and increased from 1 300 ℃ to 1 500 ℃.

  20. 煤矸石煅烧实验研究%Coal Gangue Calcined Experimental Study

    Institute of Scientific and Technical Information of China (English)

    李宏星

    2014-01-01

    This paper discusses the three major factors affecting coal gangue calcined whitening and structure changes before and after calcination,points out that the calcination process selection is the ket section,but the factors is associated,mutual penetration,should not be ignored.%论述了影响煤矸石煅烧增白的三大因素及煅烧前后的结构变化,指出煅烧工艺选择是关键,但各因素又是相关连、互相渗透的,都不应忽视。

  1. SYNTHESIS OF SnO2 NANOCRYSTALS BY SOLID STATE REACTION FOLLOWED BY CALCINATION

    Institute of Scientific and Technical Information of China (English)

    Shanmin Gao; Li Pang; Hongwei Che; Xiaoping Zhou

    2004-01-01

    Nanocrystalline SnO2 was synthesized by direct mixing and grinding of SnCl4·5H2O and NaOH at roomtemperature, followed by calcination at different temperatures for different times in air. Product samples were characterized by X-ray diffraction and transmission electron microscope, revealing that the amorphous precursor SnO2 was transformed to crystals at 200 ℃ for 3 h, and that the average particle size increased upon raising the calcining temperature or prolonging the calcining time. The mechanism of the phase transformation of the products is discussed.

  2. Test Plan for Radioactive Testing of a Vertical Direct Denitration Calciner

    International Nuclear Information System (INIS)

    Stored solutions containing plutonium and nitric acid and possibly uranium thorium and minor amounts of other substances will be used for development and demonstration of a vertical calciner direct denitration process for conversion of those to stable storable PuO2 rich solids. Some of those solutions are quite dilute and very impure these require either pretreatment to make them suitable for calciner feed or an alternate stabilization method. Untreated scrap solutions containing some amounts of sulfate phosphate sodium and/or potassium may also be tested for suitability of direct denitration for conversion directly to PuO2-rich solids. A vertical calciner will be used to demonstrate the direct denitration process for converting plutonium-bearing liquors to stable plutonium rich solids. The calciner and some of its associated equipment were previously tested with non-radioactive chemicals to demonstrate operability

  3. Design criteria for the new waste calcining facility at the Idaho Chemical Processing Plant

    International Nuclear Information System (INIS)

    The New Waste Calcining Facility (NWCF) at the Idaho Chemical Processing Plant (ICPP) is being built to replace the existing fluidized-bed, high-level waste calcining facility (WCF). Performance of the WCF is reviewed, equipment failures in WCF operation are examined, and pilot-plant studies on calciner improvements are given in relation to NWCF design. Design features of the NWCF are given with emphasis on process and equipment improvements. A major feature of the NWCF is the use of remote maintenance facilities for equipment with high maintenance requirements, thereby reducing personnel exposures during maintenance and reducing downtime resulting from plant decontamination. The NWCF will have a design net processing rate of 11.36 m3 of high-level waste per day, and will incorporate in-bed combustion of kerosene for heating the fluidized bed calciner. The off-gas cleaning system will be similar to that for the WCF

  4. Heat Transfer Characteristics of Calcined Petroleum Coke in Waste Heat Recovery Process

    Directory of Open Access Journals (Sweden)

    Bin Zheng

    2016-01-01

    Full Text Available This paper reports the results of heat transfer characteristics of calcined petroleum coke in waste heat recovery process. The model of heat exchanger was set up. The model has been used to investigate the effects of porosity (0.58 to 0.79, equivalent heat conductivity coefficient (0.9 to 1.1, and equivalent specific heat (0.9 to 1.1. The calculated values of calcined petroleum coke temperature showed good agreement with the corresponding available experimental data. The temperature distribution of calcined petroleum coke, the calcined petroleum coke temperature at heat exchanger outlet, the average heat transfer coefficient, and the heat recovery efficiency were studied. It can also be used in deriving much needed data for heat exchanger designs when employed in industry.

  5. The effect of calcination temperature on the crystallinity of TiO 2 nanopowders

    Science.gov (United States)

    Chen, Yung-Fang; Lee, Chi-Young; Yeng, Ming-Yu; Chiu, Hsin-Tien

    2003-01-01

    TiO 2 nanopowders have been prepared using 0.1 M titanium tetraisopropoxide (TTIP) in varied pH aqueous solution containing TMC and NP-204 surfactants. Only the powder acquired from a solution of pH=2 has a regular particle size distribution. Anatase phase powders are obtained by calcination in nitrogen in the 250-500°C temperature range. When calcined at 400°C, the diameter of the nanoparticles is approximately 10 nm with a specific surface area of 106.9 m 2/g. As the calcination temperature is increased, the particle size increases. Rutile phase powders are formed at calcination temperatures above 600°C.

  6. Interlock recovery during the drying, calcination and vitrification phase of Am/Cm processing

    International Nuclear Information System (INIS)

    This document summarizes the results of five CIM5 [5-inch Cylindrical Induction Melter] runs designed to demonstrate power interlock recovery methods during the drying, calcination and vitrification phases of the Am/Cm melter cycle

  7. Decomposition of bastnasite and monazite mixed rare earth minerals calcined byalkali liquid

    Institute of Scientific and Technical Information of China (English)

    XU Yanhui; LIU Haijiao; MENG Zhijun; CUI Jianguo; ZHAO Wenyi; LI Liangcai

    2012-01-01

    The process of decomposion of the bastnasite and monazite rare earth concentrates by alkali solutions was investigated.The mixed slurries of the rare earth concentrates and the alkali solutions were calcined at different temperatures in a rotary tubular electric furnace.The effects of calcination temperature on the decomposing ratio of rare earth,the oxidation ratio of cerium,the stripping of fluorine and phosphorous after calcinations,and the adaptability of the process to the mixed rare earth concentrates of different grade were studied.The results showed that the decomposition ratio of rare earth and the oxidation ratio of cerium could reach 95.8% and 93.7%,respectively,while the calcinating temperature was above 300 ℃.

  8. Synthesis of Dy2O3 nanoparticles via hydroxide precipitation:effect of calcination temperature

    Institute of Scientific and Technical Information of China (English)

    Bahaa M. Abu-Zied; Abdullah M. Asiri

    2014-01-01

    This work described the preparation of dysprosium oxide, Dy2O3, nanoparticles using the homogeneous precipitation method. Dy3+ions were precipitated using NaOH solution. The obtained product was filtered, dried, and then calcined for 1 h at the temperature range of 300-700 °C in static air. The calcination temperature of the Dy-precursor was chosen based on its decomposi-tion as indicated by the TGA analysis. The crystalline structure and surface morphology of the calcined solids were studied by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and X-ray pho-toelectron spectroscopy (XPS). The obtained results revealed that Dy2O3 with crystallites size of 11-21 nm was formed at 500 °C. Such value increased to 25-37 nm for the sample calcined at 700 °C.

  9. Kinetics Analysis on Mixing Calcination Process of Fly Ash and Ammonium Sulfate

    Institute of Scientific and Technical Information of China (English)

    Peng Wang; Laishi Li; Dezhou Wei

    2014-01-01

    abstract The further development of the extraction of alumina that is produced in the calcination process of ammonium sulfate mixed with fly ash was limited because of the lack of systematic theoretical study. In order to aggrandize the research of the calcination process, the kinetics and reaction mechanism of the calcinations were studied. The result suggests that there are two stages in the calcination process, and the alumina extraction rate increases swiftly in the initial stage, but slows down increasing in the later stage. The apparent activation energy of the initial and later stages equals to 13.31 and 35.65 kJ·mol-1, respectively. In the initial stage, ammonium sulfate reacts directly with mullite in the fly ash to form ammonium aluminum sulfate, while in the later stage, alumi-num sulfate is formed by the reaction between ammonium aluminum sulfate and ammonium sulfate.

  10. Bovine Calcined Bone for the Repair of Radial Defect in a Rabbit Model

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In order to investigate the bovine calcined bone's ability of repairing segmental bone defect and seek a new artificial bone substitute material, the bovine calcined bone (450℃,32 h) was implanted into the 10-mm middle radial defect of rabbits with tricalcium phosphate ceramics as the control. By using the methods of histology, radiology and biomechanics their osteogenic ability were measured. It was found that the bovine calcined bone's ability of repairing bone defect was better than that of tricalcium phosphate ceramics. The histological Nilsson′s scores at 3rd, 5th, 9th week after operation were significantly increased (P<0.01). At 12th week after operation the bending strength of radius in experimental group was much higher than that of control group and turned normal. It was suggested that bovine calcined bone is an ideal artificial bone substitute material with good ability of repairing segmental bone defect and some degree of mechanical strength.

  11. Effect of calcination on Co-impregnated active carbon

    Energy Technology Data Exchange (ETDEWEB)

    Bekyarova, E.; Mehandjiev, D. (Bulgarian Academy of Sciences, Sofia (Bulgaria). Inst. of General and Inorganic Chemistry)

    1993-11-01

    Active carbon (AC) from apricot shells with known characteristics has been impregnated with a 9.88% Co(NO[sub 3])[sub 2] [center dot] 6H[sub 2]O solution. The samples are destroyed in air at 200, 300, 400, and 550 C. The processes accompanying the thermal treatment are studied by DTA. Two processes are established during calcination of Co-impregnated active carbon: (i) destruction of the support as a result of oxidation catalyzed by the impregnated cobalt and (ii) interaction of the active phase (Co[sub 3]O[sub 4]) with the support (AC), during which Co[sub 3]O[sub 4] is reduced to CoO and Co. The presence of Co[sub 3]O[sub 4], and CoO phases is proved by X-ray measurements, while that of metal Co is established by magnetic measurements. The porous structure changes are investigated by adsorption studies. The characterization of the samples is performed by physical adsorption of N[sub 2] (77.4 K) and CO[sub 2] (273 K). The poresize distribution curves are plotted over the range 0.4--10 nm by the methods of Pierce (for the mesopores) and Medek (for the micropores). The micropore volume is determined by two independent methods: t/F method and D-R plot. The results from adsorption studies indicate a decrease of S[sub BET], V[sub mi], and, especially, the supermicropores of the samples.

  12. Preparation of U3O8 by calcination from ammonium uranyl carbonate in microwave fields: Process optimization

    International Nuclear Information System (INIS)

    Highlights: • The U3O8 was prepared first from ammonium uranyl carbonate using microwave. • A quadratic model was developed to optimize the process conditions. - Abstract: The effects of process conditions on preparation of U3O8 by calcination from ammonium uranyl carbonate in microwave fields were assessed and optimized for maximizing the total uranium as well as calcination temperature, adopting as Central Composite Design (CCD) methodology. The process variables assessed were calcination temperature, calcination duration and mass of sample. A quadratic model relating the process variables and the total amount of uranium and U3O8 was proposed eliminating the insignificant parameters. The optimal calcination conditions were estimated to be a calcination temperature of 942.75 K, calcination duration of 8.78 min, with the corresponding total uranium and U3O8 to be 82.07% and 31.33%, respectively

  13. Pot-Calcination Process for Converting Highly Radioactive Wastes to Solids

    International Nuclear Information System (INIS)

    The pot-calcination process has successfully converted synthetic non-radioactive Purex, TBP-25 (aluminium, HNO3) and Darex (stainless steel, HNO3) wastes to solids in both bench-scale(24 x 4 in diam.) and engineering-scale (82 X 8 in diam.) pots. The process includes feed evaporation, calcination to 900°C in the pot and recycle of the calciner vapour to the evaporator in a closed loop. Vapour from the evaporator is fractionated to produce water for disposal and nitric acid for re-use. The stainless-steel pot would be sealed after being filled and would serve as both the shipping and ultimate containment vessel. The nitrate content of the calcined solids varied between 60 and 500 ppm. Sulphate volatility during calcination of Purex waste was reduced to less than 0.8% by conversion to thermally stable sodium, magnesium, or calcium salts. Ruthenium volatility from the pot was reduced to less than 20% of the feed by the addition of phosphite or nitric oxide gas to the calciner. Steam stripping to avoid excessive acid build-up in the evaporator limited the volatility of ruthenium from the evaporator to approximately 2% of the feed. Addition of up to 1 ml/1 each of monobutyl and dibutyl phosphate to the feed to simulate solvent degradation products reduced the ruthenium volatility to < 1%. The mercury in TBP wastes was completely volatilized during calcination. Control of a 25-1 hold-up continuous evaporator close-coupled to the. engineering-scale pot calciner was demonstrated and a batch evaporation system was developed during 25 experimental tests. Average feed rates for both systems varied between 8 and 30 1/hr. Small-scale equipment (24 x 4 in diam. pots) for studying fission-product volatilities from actual wastes is installed in a hot cell at Oak Ridge National Laboratory. A 20-1/hr pilot plant for calcination of radioactive Purex, Darex, and TBP-25 wastes in 82 x 6-12-in-diam. pots is being designed for installation at the Idaho Chemical Processing Plant

  14. ICPP calcined solids storage facility closure study. Volume III: Engineering design files

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-02-01

    The following information was calculated to support cost estimates and radiation exposure calculations for closure activities at the Calcined Solids Storage Facility (CSSF). Within the estimate, volumes were calculated to determine the required amount of grout to be used during closure activities. The remaining calcine on the bin walls, supports, piping, and floor was also calculated to approximate the remaining residual calcine volumes at different stages of the removal process. The estimates for remaining calcine and vault void volume are higher than what would actually be experienced in the field, but are necessary for bounding purposes. The residual calcine in the bins may be higher than was is experienced in the field as it was assumed that the entire bin volume is full of calcine before removal activities commence. The vault void volumes are higher as the vault roof beam volumes were neglected. The estimations that follow should be considered rough order of magnitude, due to the time constraints as dictated by the project`s scope of work. Should more accurate numbers be required, a new analysis would be necessary.

  15. The leaching of base minerals from the calcines produced by the roasting of pyrite concentrates

    International Nuclear Information System (INIS)

    A number of gold and uranium plants in South Africa concentrate the pyrite in the ore residue by flotation and roast the concentrate for the production of sulphuric acid. The calcine produced, which is predominantly hematite, is generally subjected to cyanidation for the recovery of gold and silver. The calcines often contain economically significant quantities of copper, nickel , cobalt and uranium. Prior treatment of the calcine for the recovery of these metals would be desirable in terms of the value of the products. Several processes for the leaching of the base metals from plant calcines have been investigated, and an important general conclusion is that an adequate recovery of the base metals requires that a large proportion of the iron should also be extracted. This observation led to a more extensive investigation of the kinetics of leaching of various iron oxides. The application of electrochemical theory and techniques resulted in a fuller understanding of the various factors that govern the rate of leaching of iron oxides. As a result of this fundamental work, alternative treatment schemes that should yield more efficient extraction from calcines were suggested. Several of these possibilities were investigated, and the most promising were found to require reducing conditions during the leach, or prior partial reduction of the calcine to magnetite or wustite

  16. Sorption characteristics of fluoride on to magnesium oxide-rich phases calcined at different temperatures.

    Science.gov (United States)

    Sasaki, Keiko; Fukumoto, Naoyuki; Moriyama, Sayo; Hirajima, Tsuyoshi

    2011-07-15

    The effect of calcination temperature during production of magnesium oxide-rich phases from MgCO(3) on the sorption of F(-) ions in the aqueous phase has been investigated. Magnesium oxide-rich phases were formed by calcination at over 873 K for 1h. Higher calcination temperatures produced more crystalline MgO with smaller specific surface area and provided larger values of the total basicity per unit surface area. The higher calcination temperatures lead to slower F(-) removal rate, and lower equilibrium F(-) concentrations, when the equilibrium F(-) concentrations are less than 1 mmol dm(-3). Larger total basicity per unit surface area made the reactivity with F(-) ions in aqueous phase more feasible, resulting in a greater degree of F(-) sorption. For equilibrium F(-) concentrations more than 1 mmol dm(-3), lower calcination temperatures favored the co-precipitation of F(-) with Mg(OH)(2), probably leading to the formation of Mg(OH)(2-x)F(x), and the achievement of larger sorption density. This is the first paper which describes the relationship between the solid base characteristics obtained by CO(2)-TPD for MgO with different calcination temperatures as a function of the reactivity of F(-) sorption in the aqueous phase. PMID:21571430

  17. ICPP calcined solids storage facility closure study. Volume III: Engineering design files

    International Nuclear Information System (INIS)

    The following information was calculated to support cost estimates and radiation exposure calculations for closure activities at the Calcined Solids Storage Facility (CSSF). Within the estimate, volumes were calculated to determine the required amount of grout to be used during closure activities. The remaining calcine on the bin walls, supports, piping, and floor was also calculated to approximate the remaining residual calcine volumes at different stages of the removal process. The estimates for remaining calcine and vault void volume are higher than what would actually be experienced in the field, but are necessary for bounding purposes. The residual calcine in the bins may be higher than was is experienced in the field as it was assumed that the entire bin volume is full of calcine before removal activities commence. The vault void volumes are higher as the vault roof beam volumes were neglected. The estimations that follow should be considered rough order of magnitude, due to the time constraints as dictated by the project's scope of work. Should more accurate numbers be required, a new analysis would be necessary

  18. HWMA closure plan for the Waste Calcining Facility at the Idaho National Engineering Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-05-01

    The Waste Calcining Facility (WCF) calcined and evaporated aqueous wastes generated from the reprocessing of spent nuclear fuel. The calciner operated from 1963 to 1981, primarily processing high level waste from the first cycle of spent fuel extraction. Following the calciner shutdown the evaporator system concentrated high activity aqueous waste from 1983 until 1987. In 1988, US Department of Energy Idaho Operations Office (DOE-ID) requested interim status for the evaporator system, in anticipation of future use of the evaporator system. The evaporator system has not been operated since it received interim status. At the present time, DOE-ID is completing construction on a new evaporator at the New Waste Calcining Facility (NWCF) and the evaporator at the WCF is not needed. The decision to not use the WCF evaporator requires Lockheed Idaho Technologies Company (LITCO) and DOE-ID to close these units. After a detailed evaluation of closure options, LITCO and DOE-ID have determined the safest option is to fill the voids (grout the vessels, cells and waste pile) and close the WCF to meet the requirements applicable to landfills. The WCF will be covered with a concrete cap that will meet the closure standards. In addition, it was decided to apply these closure standards to the calcining system since it is contained within the WCF building. The paper describes the site, waste inventory, closure activities, and post-closure care plans.

  19. Influence of Light Calcining Hydration of Magnesite on MgO Sintering

    Institute of Scientific and Technical Information of China (English)

    LI Huan; YU Jingkun; KUANG Shibo

    2009-01-01

    Sintered magnesia clinker (also called sintered MgO ) was prepared with Mg(OH)2 (prepared by light calcining hydration of magnesite) and magnesite as starting materials, respectively, by the technical process : light calcining (850 ℃ 1 h )→grinding → molding →firing ( 1 600 ℃ 3 h ). The morphology and struc-ture of light calcined MgO powders prepared with mag-nesite or Mg(OH)2 were analyzed by XRD, SEM and FT-IR. The sinterability and microstructure of sintered magnesia prepared with magnesite or Mg(OH)2 were re-searched. The results showed that: (1) light calcined MgO powders prepared with magnesite or Mg (OH)2 were both face-centered cubic structure. The light cal-cined MgO prepared with magnesitehad the residual of functional group CO32- , and that prepared with Mg (OH)2 didn't have CO32-, and was easy to break, which reduced the grinding time. (2) Because of the high activity of the light calcined MgO prepared with Mg(OH)2 and the catalysis of the water residual in the decomposing process of Mg(OH)2, the apparent porosity of sintered magnesia decreased to 0.6% from 2.0% of before hydration, closed porosity decreased to 2.8% from 6.1%, and bulk density increased to 3.46 g·cm-3 from 3.29 g·cm-3

  20. Calcination, Reduction and Sintering of ADU Spheres for HTGR Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Kyung Chai; Eom, Sung Ho; Kim, Yeon Ku; Kim, Woong Ki; Kim, Young Min; Lee, Young Woo; Kim, Ju Hee; Cho, Hyo Jin; Cho, Moon Seoung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2011-05-15

    precipitation. The formation of spheres is then formed by the dispersed in air and ammonia gases atmosphere. The gelation of polymer was induced at the surface of the droplets in this step. The surfaces of these liquid droplets are slightly solidified by reaction of ammonia gas and uranyl ion into the droplets. Spherical droplets are converted to aged-ADU gels in NH{sub 4}OH solution. Then, many steps, such as the ageing and drying of ADU gel, the calcining to UO{sub 3}, the sintering to UO{sub 2}, were progressed continuously

  1. Design and performance of a full-scale spray calciner for nonradioactive high-level-waste-vitrification studies

    International Nuclear Information System (INIS)

    In the spray calcination process, liquid waste is spray-dried in a heated-wall spray dryer (termed a spray calciner), and then it may be combined in solid form with a glass-forming frit. This mixture is then melted in a continuous ceramic melter or in an in-can melter. Several sizes of spray calciners have been tested at PNL- laboratory scale, pilot scale and full scale. Summarized here is the experience gained during the operation of PNL's full-scale spray calciner, which has solidified approx. 38,000 L of simulated acid wastes and approx. 352,000 L of simulated neutralized wastes in 1830 h of processing time. Operating principles, operating experience, design aspects, and system descriptions of a full-scale spray calciner are discussed. Individual test run summaries are given in Appendix A. Appendices B and C are studies made by Bechtel Inc., under contract by PNL. These studies concern, respectively, feed systems for the spray calciner process and a spray calciner vibration analysis. Appendix D is a detailed structural analysis made at PNL of the spray calciner. These appendices are included in the report to provide a complete description of the spray calciner and to include all major studies made concerning PNL's full-scale spray calciner

  2. Design and performance of a full-scale spray calciner for nonradioactive high-level-waste-vitrification studies

    Energy Technology Data Exchange (ETDEWEB)

    Miller, F.A.

    1981-06-01

    In the spray calcination process, liquid waste is spray-dried in a heated-wall spray dryer (termed a spray calciner), and then it may be combined in solid form with a glass-forming frit. This mixture is then melted in a continuous ceramic melter or in an in-can melter. Several sizes of spray calciners have been tested at PNL- laboratory scale, pilot scale and full scale. Summarized here is the experience gained during the operation of PNL's full-scale spray calciner, which has solidified approx. 38,000 L of simulated acid wastes and approx. 352,000 L of simulated neutralized wastes in 1830 h of processing time. Operating principles, operating experience, design aspects, and system descriptions of a full-scale spray calciner are discussed. Individual test run summaries are given in Appendix A. Appendices B and C are studies made by Bechtel Inc., under contract by PNL. These studies concern, respectively, feed systems for the spray calciner process and a spray calciner vibration analysis. Appendix D is a detailed structural analysis made at PNL of the spray calciner. These appendices are included in the report to provide a complete description of the spray calciner and to include all major studies made concerning PNL's full-scale spray calciner.

  3. Effects of Coke Calcination Level on Pore Structure in Carbon Anodes

    Science.gov (United States)

    Fang, Ning; Xue, Jilai; Lang, Guanghui; Bao, Chongai; Gao, Shoulei

    2016-02-01

    Effects of coke calcination levels on pore structure of carbon anodes have been investigated. Bench anodes were prepared by 3 types of cokes with 4 calcination temperatures (800°C, 900°C, 1000°C and 1100°C). The cokes and anodes were characterized using hydrostatic method, air permeability determination, mercury porosimetry, image analysis and confocal microscopy (CSLM). The cokes with different calcination levels are almost the same in LC values (19-20 Å) and real density (1.967-1.985 g/cm3), while the anode containing coke calcined at 900°C has the lowest open porosity and air permeability. Pore size distribution (represented by Anode H sample) can be roughly divided into two ranges: small and medium pores in diameter of 10-400 μm and large pores of 400-580 μm. For the anode containing coke calcined at 800°C, a number of long, narrow pores in the pore size range of 400-580 μm are presented among cokes particles. Formation of these elongated pores may be attributed to coke shrinkages during the anode baking process, which may develop cracking in the anode under cell operations. More small or medium rounded pores with pore size range of 10-400 μm emerge in the anodes with coke calcination temperatures of 900°C, 1000°C and 1100°C, which may be generated due to release of volatiles from the carbon anode during baking. For the anode containing coke calcined at 1100°C, it is found that many rounded pores often closely surround large coke particles, which have potential to form elongated, narrow pores.

  4. Determination of the Rate of Formation of Hydroceramic Waste Forms made with INEEL Calcined Wastes

    Energy Technology Data Exchange (ETDEWEB)

    Barry Scheetz; Johnson Olanrewaju

    2001-10-15

    The formulation, synthesis, characterization and hydration kinetics of hydroceramic waste forms designed as potential hosts for existing INEEL calcine high-level wastes have been established as functions of temperature and processing time. Initial experimentations were conducted with several aluminosilicate pozzolanic materials, ranging from fly ash obtained from various power generating coal and other combustion industries to reactive alumina, natural clays and ground bottled glass powders. The final selection criteria were based on the ease of processing, excellent physical properties and chemical durability (low-leaching) determined from the PCT test produced in hydroceramic. The formulation contains vermiculite, Sr(NO32), CsC1, NaOH, thermally altered (calcined natural clay) and INEEL simulated calcine high-level nuclear wastes and 30 weight percent of fluorinel blend calcine and zirconia calcine. Syntheses were carried out at 75-200 degree C at autogeneous water pressure (100% relative humidity) at various time intervals. The resulting monolithic compact products were hard and resisted breaking when dropped from a 5 ft height. Hydroceramic host mixed with fluorinel blend calcine and processed at 75 degree C crumbled into rice hull-side grains or developed scaly flakes. However, the samples equally possessed the same chemical durability as their unbroken counterparts. Phase identification by XRD revealed that hydroceramic host crystallized type zeolite at 75-150 degree C and NaP1 at 175-200 degree C in addition to the presence of quartz phase originating from the clay reactant. Hydroceramic host mixed with either fluorinel blend calcine or zirconia calcine crystallized type A zeolite at 75-95 degree C, formed a mixture of type A zeolite and hydroxysodalite at 125-150 degree C and hydroxysodalite at 175-200 degree C. Quartz, calcium fluoride and zirconia phases from the clay reactant and the two calcine wastes were also detected. The PCT test solution

  5. Preparation of plutonium waste forms with ICPP calcined high-level waste

    International Nuclear Information System (INIS)

    Glass and glass-ceramic forms developed for the immobilization of calcined high-level wastes generated by Idaho Chemical Processing Plant (ICPP) fuel reprocessing activities have been investigated for ability to immobilize plutonium and to simultaneously incorporate calcined waste as an anti-proliferation barrier. Within the forms investigated, crystallization of host phases result in an increased loading of plutonium as well as its incorporation into potentially more durable phases than the glass. The host phases were initially formed and characterized with cerium (Ce+4) as a surrogate for plutonium (Pu+4) and samarium as a neutron absorber for criticality control. Verification of the surrogate testing results were then performed replacing cerium with plutonium. All testing was performed with surrogate calcined high-level waste. The results of these tests indicated that a potentially useful host phase, based on zirconia, can be formed either by devitrification or solid state reaction in the glass studied. This phase incorporates plutonium as well as samarium and the calcined waste becomes part of the matrix. Its ease of formation makes it potentially useful in excess plutonium dispositioning. Other durable host phases for plutonium and samarium, including zirconolite and zircon have been formed from zirconia or alumina calcine through cold press-sintering techniques and hot isostatic pressing. Host phase formation experiments conducted through vitrification or by cold press-sintering techniques are described and the results discussed. Recommendations are given for future work that extends the results of this study

  6. Spray Calciner/In-Can Melter high-level waste solidification technical manual

    International Nuclear Information System (INIS)

    This technical manual summarizes process and equipment technology developed at Pacific Northwest Laboratory over the last 20 years for vitrification of high-level liquid waste by the Spray Calciner/In-Can Melter process. Pacific Northwest Laboratory experience includes process development and demonstration in laboratory-, pilot-, and full-scale equipment using nonradioactive synthetic wastes. Also, laboratory- and pilot-scale process demonstrations have been conducted using actual high-level radioactive wastes. In the course of process development, more than 26 tonnes of borosilicate glass have been produced in 75 canisters. Four of these canisters contained radioactive waste glass. The associated process and glass chemistry is discussed. Technology areas described include calciner feed treatment and techniques, calcination, vitrification, off-gas treatment, glass containment (the canister), and waste glass chemistry. Areas of optimization and site-specific development that would be needed to adapt this base technology for specific plant application are indicated. A conceptual Spray Calciner/In-Can Melter system design and analyses are provided in the manual to assist prospective users in evaluating the process for plant application, to provide equipment design information, and to supply information for safety analyses and environmental reports. The base (generic) technology for the Spray Calciner/In-Can Melter process has been developed to a point at which it is ready for plant application

  7. Spray Calciner/In-Can Melter high-level waste solidification technical manual

    Energy Technology Data Exchange (ETDEWEB)

    Larson, D.E. (ed.)

    1980-09-01

    This technical manual summarizes process and equipment technology developed at Pacific Northwest Laboratory over the last 20 years for vitrification of high-level liquid waste by the Spray Calciner/In-Can Melter process. Pacific Northwest Laboratory experience includes process development and demonstration in laboratory-, pilot-, and full-scale equipment using nonradioactive synthetic wastes. Also, laboratory- and pilot-scale process demonstrations have been conducted using actual high-level radioactive wastes. In the course of process development, more than 26 tonnes of borosilicate glass have been produced in 75 canisters. Four of these canisters contained radioactive waste glass. The associated process and glass chemistry is discussed. Technology areas described include calciner feed treatment and techniques, calcination, vitrification, off-gas treatment, glass containment (the canister), and waste glass chemistry. Areas of optimization and site-specific development that would be needed to adapt this base technology for specific plant application are indicated. A conceptual Spray Calciner/In-Can Melter system design and analyses are provided in the manual to assist prospective users in evaluating the process for plant application, to provide equipment design information, and to supply information for safety analyses and environmental reports. The base (generic) technology for the Spray Calciner/In-Can Melter process has been developed to a point at which it is ready for plant application.

  8. Influence of acid leaching and calcination on iron removal of coal kaolin

    Science.gov (United States)

    Zhu, Pei-wang; Zeng, Wei-qiang; Xu, Xiu-lin; Cheng, Le-ming; Jiang, Xiao; Shi, Zheng-lun

    2014-04-01

    Calcination and acid leaching of coal kaolin were studied to determine an effective and economical preparation method of calcined kaolin. Thermogravimetric-differential thermal analysis (TG-DTA) and X-ray diffraction (XRD) demonstrated that 900°C was the suitable temperature for the calcination. Leaching tests showed that hydrochloric acid was more effective for iron dissolution from raw coal kaolin (RCK), whereas oxalic acid was more effective on iron dissolution from calcined coal kaolin (CCK). The iron dissolution from CCK was 28.78wt%, which is far less effective than the 54.86wt% of RCK under their respective optimal conditions. Through analysis by using Mössbauer spectroscopy, it is detected that nearly all of the structural ferrous ions in RCK were removed by hydrochloric acid. However, iron sites in CCK changed slightly by oxalic acid leaching because nearly all ferrous ions were transformed into ferric species after firing at 900°C. It can be concluded that it is difficult to remove the structural ferric ions and ferric oxides evolved from the structural ferrous ions. Thus, iron removal by acids should be conducted prior to calcination.

  9. Influence of acid leaching and calcination on iron removal of coal kaolin

    Institute of Scientific and Technical Information of China (English)

    Pei-wang Zhu; Wei-qiang Zeng; Xiu-lin Xu; Le-ming Cheng; Xiao Jiang; Zheng-lun Shi

    2014-01-01

    Calcination and acid leaching of coal kaolin were studied to determine an effective and economical preparation method of calcined kaolin. Thermogravimetric-differential thermal analysis (TG-DTA) and X-ray diffraction (XRD) demonstrated that 900°C was the suitable temperature for the calcination. Leaching tests showed that hydrochloric acid was more effective for iron dissolution from raw coal kaolin (RCK), whereas oxalic acid was more effective on iron dissolution from calcined coal kaolin (CCK). The iron dissolution from CCK was 28.78wt%, which is far less effective than the 54.86wt% of RCK under their respective optimal conditions. Through analysis by using Mössbauer spectroscopy, it is detected that nearly all of the structural ferrous ions in RCK were removed by hydrochloric acid. However, iron sites in CCK changed slightly by oxalic acid leaching because nearly all ferrous ions were transformed into ferric species after firing at 900°C. It can be concluded that it is difficult to remove the structural ferric ions and ferric oxides evolved from the structural ferrous ions. Thus, iron removal by acids should be conducted prior to calcination.

  10. Effect of Calcined Temperature on the Solubility of Trace Elements from Manifanshi

    Institute of Scientific and Technical Information of China (English)

    HONG Hanlie; TIE Liyun; BIAN Qiujuan; ZHOU Yong

    2006-01-01

    A medical stone manifanshi were researched by using polarized light microscopy, X-ray diffraction (XRD), and inductively coupled plasma atomic emission spectrometry (ICP-AES) methods. The XRD pattern of the raw Manifanshi indicates that it is dominantly composed of plagioclase, orthoclase, quartz, and that of the calcined Manifanshi at 1000 ℃ shows that the distortion of crystal structure in both plagioclase and orthoclase takes place at the calcined temperature. The polarized light microscopy observation suggests that the Manifanshi is naturally weathered monzo-granite porphyry. Chemical analyses reveal that the Manifanshi contains a number of healthful trace elements and rare toxic trace elements, therefore, it is a high quality Manifanshi. The solubility of trace elements was determined by measuring the concentration of trace elements from Manifanshi calcined under varying temperature conditions by ICP method, the results suggest that the calcined product at 1000 ℃ shows the ideal result in ionic concentrations and dissolution rate of trace elements in water, which is contributed to the distortion of the crystal structure of feldspar at the calcined temperature.

  11. Effect of fly ash preliminary calcination on the properties of geopolymer.

    Science.gov (United States)

    Temuujin, J; van Riessen, A

    2009-05-30

    The influence of preliminary calcination of fly ashes on the geopolymerisation process has been studied. Preliminary calcination at 500 and 800 degrees C causes decarbonation of the fly ash while it also leads to a decrease of the amorphous content of the fly ashes from 60 to 57%. Geopolymer prepared using raw fly ash exhibited a compressive strength 55.7(9.2)MPa, while for 500 and 800 degrees C calcined samples it reduced to 54(5.8) and 44.4(5.4)MPa, respectively. The decrease in compressive strength of the geopolymers is discussed in terms of partial surface crystallisation of the fly ash particles. Reactivity of the fly ash also has been correlated with the shrinkage rate and presence of efflorescence on the surface of geopolymers.

  12. Effect of Different Calcination Duration on Physicochemical Properties of Vanadium Phosphate Catalysts

    Directory of Open Access Journals (Sweden)

    Yun Hin Taufiq-Yap

    2012-01-01

    Full Text Available Vanadium phosphate catalysts have been prepared by calcining VOHPO44·0.5H2O which were prepared via two methods i.e. organic (VPO method and dihydrate (VPD method routes for different duration under anaerobic atmosphere. Increasing the calcinations duration led to a decrease in total surface area. It is also promote the formation of V5+ phase in the catalysts. Scanning electron microscopy clearly revealed that the morphologies of all catalysts composed of plate-like crystallites that were arranged into the characteristic of rosette cluster. However, by increasing the pretreatment duration in an inert environment, the rosette-shape of the clusters which normally obtained in reaction condition was collapsed. Prolong the duration of N2 calcination also resulted in an increment in the amount of oxygen desorbed (from O2-TPD and removed (obtained from H2-TPR.

  13. Characterisation of sugar cane straw waste as pozzolanic material for construction: Calcining temperature and kinetic parameters

    International Nuclear Information System (INIS)

    This paper reports on the influence of calcining temperature (800 and 1000 deg. C) on the pozzolanic activation of sugar cane straw (SCS). The reaction kinetics of SCS ash-lime mixtures were inferred from physicochemical characteristics (X-ray diffraction patterns and thermogravimetry analysis. The fitting of a kinetic-diffusive model to the experimental data (fixed lime versus time) allowed the computing of the kinetic parameters (reaction rate constant) of the pozzolanic reaction. Results obtained confirm that the sugar cane straw ash (SCSA) calcined at 800 and 1000 deg. C have properties indicative of very high pozzolanic activity. No influence of calcining temperature on the pozzolanic activity was observed. Also, no crystalline compounds during the pozzolanic reaction were identified up to 90 days of reaction. Environmental durability and strength of the consequential mortars remain to be assessed

  14. Effect of calcination temperature on the photocatalytic properties of electrospun TiO2 nanofibers.

    Science.gov (United States)

    Lee, Young-In; Lee, Jong-Sik; Park, Eun-Sil; Jang, Dae-Hwan; Lee, Jae-Eun; Kim, Kahee; Myung, Nosang V; Choa, Yong-Ho

    2014-10-01

    In this study, TiO2 nanofibers with a high aspect ratio and a large specific surface area were synthesized using the electrospinning technique, and the effect of calcination temperature on their crystal structure, diameter, specific surface area and photocatalytic activity was systematically investigated. The electrospun, as-prepared PVP/TTIP nanofibers were several tens of micrometers in length with a diameter of 74 nm. TiO2 nanofibers with an average diameter of 50 nm were prepared after calcination at various temperatures. The calcination temperature significantly influenced the photocatalytic and material properties of TiO2 including grain size and specific surface area. When compared to other nanostructured TiO2 materials, such as commercial TiO2 nanoparticles (P25, Degussa), the TiO2 nanofibers exhibited greater photocatalytic activity for the degradation of acetaldehyde and ammonia. PMID:25942911

  15. Heavy metal removal from acid mine drainage by calcined eggshell and microalgae hybrid system.

    Science.gov (United States)

    Choi, Hee-Jeong; Lee, Seung-Mok

    2015-09-01

    This study investigates the use of calcined eggshells and microalgae for the removal of heavy metals from acid mine drainage (AMD) and the simultaneous enhancement of biomass productivity. The experiment was conducted over a period of 6 days in a hybrid system containing calcined eggshells and the microalgae Chlorella vulgaris. The results show that the biomass productivity increased to ~8.04 times its initial concentration of 0.367 g/L as measured by an optical panel photobioreactor (OPPBR) and had a light transmittance of 95 % at a depth of 305 mm. On the other hand, the simultaneous percent removal of Fe, Cu, Zn, Mn, As, and Cd from the AMD effluent was found to be 99.47 to 100 %. These results indicate that the hybrid system with calcined eggshells and microalgae was highly effective for heavy metal removal in the AMD.

  16. An Assessment of Using Vibrational Compaction of Calcined HLW and LLW in DWPF Canisters

    International Nuclear Information System (INIS)

    Since 1963, the INEL has calcined almost 8 million gallons of liquid mixed waste and liquid high-level waste, converting it to some 1.1 million gallons of dry calcine (about 4275.0 m3), which consists of alumina-and zirconia-based calcine and zirconia-sodium blend calcine. In addition, if all existing and projected future liquid wastes are solidified, approximately 2,000 m3 of additional calcine will be produced primarily from sodium-bearing waste. Calcine is a more desirable material to store than liquid radioactive waste because it reduces volume, is much less corrosive, less chemically reactive, less mobile under most conditions, easier to monitor and more protective of human health and the environment. This paper describes the technical issue involved in the development of a feasible solution for further volume reduction of calcined nuclear waste for transportation and long term storage, using a standard DWPF canister. This will be accomplished by developing a process wherein the canisters are transported into a vibrational machine, for further volume reduction by about 35%. The random compaction experiments show that this volume reduction is achievable. The main goal of this paper is to demonstrate through computer modeling that it is feasible to use volume reduction vibrational machine without developing stress/strain forces that will weaken the canister integrity. Specifically, the paper presents preliminary results of the stress/strain analysis of the DWPF canister as a function of granular calcined height during the compaction and verifying that the integrity of the canister is not compromised. This preliminary study will lead to the development of better technology for safe compactions of nuclear waste that will have significant economical impact on nuclear waste storage and treatment. The preliminary results will guide us to find better solutions to the following questions: 1) What are the optimum locations and directions (vertical versus horizontal or

  17. Removal of hexavalent chromium from aqueous solution by calcined Zn/Al-LDHs.

    Science.gov (United States)

    Yang, Hui-Duo; Zhao, Yun-Peng; Li, Shi-Feng; Fan, Xing; Wei, Xian-Yong; Zong, Zhi-Min

    2016-01-01

    In this study, Zn/Al-layered double hydroxides (Zn/Al-LDHs) were synthesized by a co-precipitation method and characterized with X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. Then the hexavalent chromium Cr(VI) adsorption experiments on calcined Zn/Al-LDHs were carried out to analyze the effects of pH, temperature, adsorption time, initial Cr(VI) concentration and adsorbent dosage on the removal of Cr(VI) from aqueous solutions. The maximum adsorption capacity for Cr(VI) on calcined Zn/Al-LDHs under optimal conditions was found to be over 120 mg/g. The kinetic and isotherm of Cr(VI) adsorption on calcined Zn/Al-LDHs can be described with the pseudo-second-order kinetic model and Langmuir isotherm, respectively. PMID:27387001

  18. Calcination of Fluorinel-sodium waste blends using sugar as a feed additive (formerly WINCO-11879)

    International Nuclear Information System (INIS)

    Methods were studied for using sugar as a feed additive for converting the sodium-bearing wastes stored at the Idaho Chemical Processing Plant into granular, free flowing solids by fluidized-bed calcination at 500 degrees C. All methods studied blended sodium-bearing wastes with Fluorinel wastes but differed in the types of sugar (sucrose or dextrose) that were added to the blend. The most promising sugar additive was determined to be sucrose, since it is converted more completely to inorganic carbon than is dextrose. The effect of the feed aluminum-to-alkali metal mole ratio on calcination of these blends with sugar was also investigated. Increasing the aluminum-to-alkali metal ratio from 0.6 to 1.0 decreased the calcine product-to-fines ratio from 3.0 to 1.0 and the attrition index from 80 to 15%. Further increasing the ratio to 1.25 had no effect

  19. Mensuration of microstructure multi-fractal spectra of calcined limestone particle surfaces

    Institute of Scientific and Technical Information of China (English)

    Jianyu Shang; Songling Wang; Chunbo Wang; Chunchang Song

    2010-01-01

    The microstructure of the surface of a calcined limestone particle is multi-fractal.We develop an analytic method that surveys the boundary curve multi-fractal dimensions with SEM,gets a three-dimensional surface structure α-f(α)curve via zero-sets,and finally calculates the multi-fractal spectrum values of the particle surface's microstructural topography.After analyzing two spectra from limestone particles calcined at 850 ℃ and 900 ℃,it was shown that the microstructural topographies of the surfaces of calcined limestone multi-particle system have some degree of self-similarity.This mensuration method is proposed to describe the multi-fractal characteristics of a micro-scale particle's surface topography.

  20. Effects of nanosized metallic palladium loading and calcination on characteristics of composite silica

    Institute of Scientific and Technical Information of China (English)

    吴玉程; 吴侠; 李广海; 张立德

    2003-01-01

    In order to investigate the effects of nanosized metallic palladium loading and calcination on the characteristics of composite silica,the silica was prepared by sol-gel technique,leading to an amorphous solid with mesoporosity,and the pore size distribution is narrow,centered at 3-5 nm.The composite silica was formed by impregnating palladium precursor into the porous network with sequel calcination in hydrogen.The results show that the nanosized palladium as guest phase in the composite silica is subjected to the mesoporous structure and calcination,resulting in the changes of optical adsorption that red-shifted to higher wavelength with the palladium loading and the heating temperature.The tailoring of the optical properties can be ascribed to the effect of the nanosized metal particles and interactions occurred between palladium and silica.

  1. Numerical study of co-firing pulverized coal and biomass inside a cement calciner.

    Science.gov (United States)

    Mikulčić, Hrvoje; von Berg, Eberhard; Vujanović, Milan; Duić, Neven

    2014-07-01

    The use of waste wood biomass as fuel is increasingly gaining significance in the cement industry. The combustion of biomass and particularly co-firing of biomass and coal in existing pulverized-fuel burners still faces significant challenges. One possibility for the ex ante control and investigation of the co-firing process are computational fluid dynamics (CFD) simulations. The purpose of this paper is to present a numerical analysis of co-firing pulverized coal and biomass in a cement calciner. Numerical models of pulverized coal and biomass combustion were developed and implemented into a commercial CFD code FIRE, which was then used for the analysis. Three-dimensional geometry of a real industrial cement calciner was used for the analysis. Three different co-firing cases were analysed. The results obtained from this study can be used for assessing different co-firing cases, and for improving the understanding of the co-firing process inside the calculated calciner.

  2. Biodiesel production from waste cooking oil using calcined scallop shell as catalyst

    International Nuclear Information System (INIS)

    Highlights: • Calcined scallop shell was used as low-cost and effective catalyst for biodiesel production. • BDF yield from waste cooking oil reached 86% at 65 °C with a catalyst loading amount of 5 wt%. • Calcined scallop shell showed good reusability. • Calcium glyceroxide played an important role on the reusability of calcined scallop shell. • Water in the waste cooking oil had negative effect on the catalytic activity of calcined scallop shell. - Abstract: Transesterification of waste cooking oil (WCO) and methanol by using calcined scallop shell (CSS) as catalyst was carried out in a closed system for biodiesel fuel (BDF) production. It is found that the optimum calcination temperature for the preparation of CSS was 1000 °C. The effects of transesterification temperature, reaction time, methanol/oil molar ratio and catalyst loading amount on the BDF yield were investigated. Compared with the commercial CaO, CSS showed higher catalytic activity and the BDF yield reached 86% at 65 °C with a catalyst loading amount of 5 wt% (WCO basis) and a reaction time of 2 h. The catalyst was reused for 5 cycles whilst the BDF yield decreased 23%. It is found that CaO in CSS was transferred to calcium glyceroxide after the transesterification reaction, and calcium glyceroxide also showed good catalytic activity and reusability. Furthermore, Water content in WCO had negative effect on BDF yield. It is found that BDF yield reduced 15% due to the occurring of saponification when the water content was increased from 0.64% to 2.48%. It is expected that CCS can be used as an alternative and cheap catalyst for the biodiesel production

  3. Incineration of contaminated organic solvents in a fluidized-bed calciner

    International Nuclear Information System (INIS)

    The reprocessing of expended reactor fuels at the Idaho Chemical Processing Plant (ICPP) generates contaminated organic solvents. An evaluation of potential management alternatives shows that several are suitable for management of contaminated solvents containing tri-butyl phosphate (TBP): the solvent could be burned in a commercially-available burner which absorbs the phosphorus on a fluidized-bed of limestone leaving a solid product for burial; the solvent could be burned in a small fluidized-bed calciner which solidifies non-radioactive feed by in-bed combustion of the contaminated solvent. The fluidized-bed absorbs the phosphate forming a solid product for burial; the solvents could be solidified with a gel or sorbant for burial if the reprocessing system were modified to reduce the solvent volume; and the contaminated solvent could be burned in an existing fluidized-bed calciner designed for solidifying high-level aqueous wastes. Burning the solvent in the existing calciner was selected for process verification because it provides an existing burner, off-gas system, and solids transfer and storage system. No additional wastes are generated. A set of four pilot-plant tests verified the absence of adverse effects from the phosphorus in the fuel when calcining simulated ICPP aqueous wastes. Essentially all of the phosphorus remained in the calcined solids with only a neglegible quantity remaining in the scrubbed off-gas. Combustion efficiency was high (93 to 96%). There were no observable adverse effects on solids in the scrubbing system, corrosion rates, or solids flowability (for retrieval). Conclusions of general applicability are: alternative technologies are available for disposal of contaminated solvents, and the use of an existing fuel-using facility, e.g., calciner or incinerator - designed for contaminated wastes will usually be cost effective

  4. ICPP radioactive liquid and calcine waste technologies evaluation final report and recommendation

    International Nuclear Information System (INIS)

    Using a formalized Systems Engineering approach, the Latched Idaho Technologies Company developed and evaluated numerous alternatives for treating, immobilizing, and disposing of radioactive liquid and calcine wastes at the Idaho Chemical Processing Plant. Based on technical analysis data as of March, 1995, it is recommended that the Department of Energy consider a phased processing approach -- utilizing Radionuclide Partitioning for radioactive liquid and calcine waste treatment, FUETAP Grout for low-activity waste immobilization, and Glass (Vitrification) for high-activity waste immobilization -- as the preferred treatment and immobilization alternative

  5. ICPP radioactive liquid and calcine waste technologies evaluation final report and recommendation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-04-01

    Using a formalized Systems Engineering approach, the Latched Idaho Technologies Company developed and evaluated numerous alternatives for treating, immobilizing, and disposing of radioactive liquid and calcine wastes at the Idaho Chemical Processing Plant. Based on technical analysis data as of March, 1995, it is recommended that the Department of Energy consider a phased processing approach -- utilizing Radionuclide Partitioning for radioactive liquid and calcine waste treatment, FUETAP Grout for low-activity waste immobilization, and Glass (Vitrification) for high-activity waste immobilization -- as the preferred treatment and immobilization alternative.

  6. Study of structural transformations and phases formation upon calcination of Zn–Ni–Al hydrotalcite nanosheets

    Indian Academy of Sciences (India)

    Zhanshuang Li; Yanchao Song; Jun Wang; Qi Liu; Piaoping Yang; Milin Zhang

    2011-04-01

    In this paper, we describe a general process for the synthesis of highly crystalline Zn–Ni–Al hydrotalcitelike materials. The structure and thermal decomposition of the prepared samples are studied by XRD, FT–IR, TG–DSC, SEM, TEM and N2 adsorption/desorption. The morphology of large-sized, porous and hexagonal platelike Zn–Ni–Al hydrotalcite is affected by calcination temperature. BET specific surface area and pore volume are observed to increase with increase of the calcination temperature up to 700°C followed by a further decrease with increasing temperature.

  7. Study of as-synthesized and calcined hydrocalumites as possible antacid agents

    Indian Academy of Sciences (India)

    Carlos F Linares; Freddy Ocanto; Pablo Bretto; Maricela Monsalve

    2014-06-01

    A hydrocalumite-type solid was synthesized by the homogeneous co-precipitation method by using Ca and Al nitrate solutions in a basic medium (NaOH). This solid was calcined at 700 and 900 °C, respectively. Then, solids were characterized by X-ray diffraction, FT–IR spectroscopy and BET surface area measurements. Finally, these solids were tested as antacids by using a synthetic gastric juice. Results showed that calcined samples were able to neutralize the synthetic gastric juice in more extension as an as-synthesized hydrocalumite; however, the last solid showed better conditions as a potential antacid.

  8. Heat Transfer Characteristics of Calcined Petroleum Coke in Waste Heat Recovery Process

    OpenAIRE

    Bin Zheng; Yongqi Liu; Lichen Zou; Ruiyang Li

    2016-01-01

    This paper reports the results of heat transfer characteristics of calcined petroleum coke in waste heat recovery process. The model of heat exchanger was set up. The model has been used to investigate the effects of porosity (0.58 to 0.79), equivalent heat conductivity coefficient (0.9 to 1.1), and equivalent specific heat (0.9 to 1.1). The calculated values of calcined petroleum coke temperature showed good agreement with the corresponding available experimental data. The temperature distri...

  9. Ethanol Total Oxidation Over Calcined Layered Double Hydroxides Modified with Organic Components

    OpenAIRE

    Kovanda, F.; Zapivovarski Votipka, Z.; Raabová, H.; Jirátová, K. (Květa); Klempa, J. (Jan); Ludvíková, J. (Jana)

    2013-01-01

    Coprecipitation of Co, Mn, and Al nitrates by a solution of Na2CO3 and NaOH in the presence of Pluronic ® P123 has led to layered double hydroxide (LDH) precursors with hydrotalcite-like structure. Their calcination gave spinel-type mixed oxides; the presence of organic template increased both BET and mesopore surface areas of the calcined products. TPR profiles of the samples modified with Pluronic ® P123 exhibited a shift of reduction maxima to lower temperatures, similarly as increasing so...

  10. Remote design criteria and philosophy of the New Waste Calcining Facility

    International Nuclear Information System (INIS)

    A New Waste Calcining Facility is being built at the Idaho Chemical Processing Plant to replace the existing Waste Calcining Facility which was built to demonstrate fluidized-bed solidification of highly radioactive liquid wastes. The new facility will include significant remote features and provisions for effecting major reductions in the annual personnel radiation exposures being experienced at the Idaho Chemical Processing Plant. Past Chemical Processing Plant equipment failure histories and personnel radiation exposure histories are described along with corrective actions being taken in the new facility to reduce exposures and the anticipated results of those actions

  11. Effect of calcination conditions on microstructures and Jc of YBCO films fabricated by TFA-MOD method

    International Nuclear Information System (INIS)

    YBCO films were grown on LaAlO3 substrates by a metal organic deposition using trifluoroacetates (TFA-MOD). In the TFA-MOD method, a starting solution is coated on a substrate firstly, and then the coated film is calcined to form precursor and finally the precursor film is crystallized to form superconducting YBCO film. In this study, the effects of calcination conditions such as temperature on the microstructures and Jc properties of the YBCO films were studied. In the calcination step, spin coating and calcination were repeated three times for obtaining thick film under the maximum temperatures of 400-500 deg. C. The prepared precursor films were crystallized at a constant condition. The Jc values of the films calcined at 500 deg. C after at 400 deg. C x 2 times, 400 deg. C x 3 times and 500 deg. C x 3 times were about 1.49 MA/cm2, 2.52 MA/cm2 and 1.47 MA/cm2, respectively. Jc depended strongly on the calcination temperature. The cross-sectional TEM images showed that the YBCO film calcined at 400 deg. C x 3 times had less pores than the others. Optimization of the calcination temperature was important to suppress the formation of large precipitates in precursor film, resulting in the suppression of the large pores in the YBCO film

  12. 石油焦煅烧技术方案比较%Comparison of calcination technical schemes of petroleum coke

    Institute of Scientific and Technical Information of China (English)

    穆二军; 刘慧

    2013-01-01

    This paper presents comparisons of different calcination technologies,such as the vertical shaft calciner, rotary kiln,rotary hearth furnace and electrically calcined furnace. The comparisons from process performance perspective, thermodynamic principle, calcination technology, calcination product quality, environment of engineering construction and the main technical and economic indexes etc., are made. The characteristics of different calcination technologies in the production of anode used in aluminum industry are discussed, the advantages and disadvantages of different calcination technology are analyzed, and further optimizing for the design and operation of the main calcination technology is pointed out.%对罐式炉、回转窑、回转床、电煅炉等炭素煅烧处理方式从工艺流程、热工原理、煅烧工艺技术、煅烧质量、工程建设环境及主要技术经济指标等方面进行综合比较;基于目前生石油焦质量与供应等情况,讨论了石油焦煅烧技术对生产铝用阳极焦的适应性;分析了不同煅烧方式的优缺点,提出了对主要煅烧技术需进一步优化设计与工艺操作的建议.

  13. 46 CFR 148.04-15 - Petroleum coke, uncalcined; petroleum coke, uncalcined and calcined (mixture).

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Petroleum coke, uncalcined; petroleum coke, uncalcined and calcined (mixture). 148.04-15 Section 148.04-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND... Requirements for Certain Material § 148.04-15 Petroleum coke, uncalcined; petroleum coke, uncalcined...

  14. Oxidative dehydrogenation of ethylbenzene to styrene over alumina : effect of calcination

    NARCIS (Netherlands)

    Nederlof, Christian; Zarubina, Valeriya; Melian-Cabrera, Ignacio; Heeres, Hero Jan (Eric); Kapteijn, Freek; Makkee, Michiel

    2013-01-01

    Commercially available gamma-Al2O3 was calcined at temperatures between 500 and 1200 degrees C and tested for its performance in the oxidative ethylbenzene dehydrogenation (ODH) over a wide range of industrially-relevant conditions. The original gamma-Al2O3, as well as Z- and alpha-Al2O3, were teste

  15. Calcined eggshell (CES): An efficient natural catalyst for Knoevenagel condensation under aqueous condition

    Indian Academy of Sciences (India)

    Suresh Patil; Swati D Jadhav; M B Deshmukh

    2013-07-01

    A convenient, eco-friendly and economic method for Knoevenagel condensation of aromatic aldehydes with active methylene compounds using calcined eggshell (CES) as an efficient natural catalyst in aqueous medium has been reported. CES is a new, ecologically safe and inexpensive green catalyst obtained from renewable resources.

  16. Synthesis of alumina powder with seeds by Pechini Method using O2 as calcination atmosphere

    International Nuclear Information System (INIS)

    Alumina is a very investigated material due to its excellent refractory characteristics and mechanical properties. Its alpha phase, the most stable one, has a formation temperature of about 1200 ° C. Due to its high temperature of formation, many researches have been trying to reduce it through addition of seeds of alpha phase in chemical processes of synthesis. This work aims to synthesize ultrafine powders of alpha-alumina by the Pechini method with seeding, and using an O2 atmosphere in the pre-calcination (500 ° C) and calcination (1000 ° C and 1100° C) steps. The resulting powders were characterized through X-ray diffractometry, infrared spectroscopy and scanning electron microscopy. The results were compared with samples calcined on ai. It was verified that the presence of oxygen in the calcination atmosphere favored the elimination of residual carbon from the precursor powders, forthcoming from the great amount of organic material used on the synthesis, modifying its morphology and favoring reduction of particle size. (author)

  17. Effect of the rate of calcination of kaolin on the properties of metakaolin-based geopolymers

    Directory of Open Access Journals (Sweden)

    B.B. Kenne Diffo

    2015-03-01

    Full Text Available Kaolin samples of the same mass were treated at 700 °C for the same duration of 30 min by varying the rate of calcination (1, 2.5, 5, 10, 15 and 20 °C/min in order to obtain metakaolins which were used to produce geopolymers. Depending on the nature of each type of material, kaolin, metakaolins and geopolymers were characterized using thermal analysis, chemical analysis, XRD, FTIR, particle size distribution, specific surface area, bulk density, setting time and compressive strength. FTIR and XRD analyses showed that metakaolins except at 1 °C/min contained residual kaolinite whose quantity increased with the rate of calcination of kaolin and which influenced the characteristics of geopolymers. Thus as the rate of calcination of kaolin increased, the setting time increased (226 min (rate of 1 °C/min–773 min (rate of 20 °C/min while the compressive strength reduced (49.4 MPa (rate of 1 °C/min–20.8 MPa (rate of 20 °C/min. From the obtained results the production of geopolymers having high compressive strength along with low setting time requires that the calcination of kaolin be carried out at a low rate.

  18. Restart Plan for the Prototype Vertical Denitration Calciner [SD Coversheet has Incorrect Document Number

    Energy Technology Data Exchange (ETDEWEB)

    SUTTER, C.S.

    1999-07-26

    Testing activities on the Prototype Vertical Denitration Calciner at PFP were suspended in January 1997 due to the hold on fissile material handling in the facility. The Restart Plan will govern the transition of the test program from the completion of the activity based startup review; through equipment checkout and surrogate material runs; to resumption of the testing program and transition to unrestricted testing.

  19. Calcination/acid-activation treatment of an anodic oxidation TiO2/Ti film catalyst

    Institute of Scientific and Technical Information of China (English)

    YAO Zhongping; JIANG Yanli; JIANG Zhaohua; ZHU Hongkui; BAI Xuefeng

    2009-01-01

    The aim of this work was to investigate the effects of calcination/acid-activation on the composition, structure, and photocatalytic (PC) re-duction property of an anodic oxidation TiO2/Ti film catalyst. The surface morphology and phase composition were examined by scanning electron microscopy and X-ray diffraction. The catalytic property of the film catalysts was evaluated through the removal rate of potassium chromate during the PC reduction process. The results showed that the film catalysts were composed of anatase and mtile TiO2 with a mi-cro-porous surface structure. The calcination treatment increased the content of TiO2 in the film, changed the relative ratio of anatase and rutile TiO2, and decreased the size of the micro pores of the film cat.a/ysts. The removal rate of potassium chromate was related to the tech-nique parameters of calcination/acid-activation treatment. When the anodic oxidation TiO2Ti film catalyst was calcined at 873 K for 30 min and then acid-activated in the concentrated H2SO4 for 60 min, it presented the highest catalytic property, with the removal rate of potassium chromate of 96.3% during the PC reduction process under the experimental conditions.

  20. Effect of Boric Acid on Properties of Calcined Flint Clay-Bauxite Castables

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wei; DAI Wenyong

    2010-01-01

    In order to prolong the working time of calcined flint clay-bauxite castables during construction at high temperature,boric acid was added into the castables.The effect of boric acid on working time and curing cold crushing strength of the castables at 25 ℃ and 35 ℃were investigated.After 24 h curing in mould and another 24 h curing at 110 ℃ after demoulding,the specimens were heat treated at 1 000 ℃,1 300 ℃,and1 500 ℃ for 3 h,respectively.The permanent linear change,bulk density,modulus of rupture,and cold crushing strength were determined.The result shows that there is no need to add boric acid when calcined flint clay-bauxite ca.stables works at 25 ℃ ; when calcined flint clay-bauxite castables works at 35 ℃,boric acid can increase the working time of the castables,but decrease the curing cold crushing strength a little.Adding boric acid into calcined flint clay-bauxite castables doesn' t worsen performance of the castablcs.

  1. Method and apparatus for evaporating radioactive liquid and calcinating the residue

    International Nuclear Information System (INIS)

    This invention provides an apparatus and a process for evaporating liquid wastes and calcining the residue. The liquid is sprayed against a hollow, rotating heated cylinder within a casing. The dried residue is scraped from the rotating cylinder and released through a valve at the bottom of the casing, while the effluent gas is filtered

  2. Chemical and mineralogical modifications of simplified radioactive waste calcine during heat treatment

    Science.gov (United States)

    Monteiro, A.; Schuller, S.; Toplis, M. J.; Podor, R.; Ravaux, J.; Clavier, N.; Brau, H. P.; Charpentier, T.; Angeli, F.; Leterrier, N.

    2014-05-01

    The microstructural and mineralogical changes associated with heating calcined mixtures of Al(NO3)3ṡ9H2O-NaNO3 have been studied. This system is a simplified analogue of high-level radioactive waste calcine, one of the raw materials used in the vitrification process employed for waste management. The decomposition (dehydration and denitration) and formation of secondary crystalline phases have been studied by differential thermal and gravimetric analysis (DTA & TGA), and heat-treated products characterized by X-ray diffraction, Raman spectroscopy, Nuclear Magnetic Resonance (NMR) and Transmission Electron Microscopy (TEM). It is found that pure Al(NO3)3ṡ9H2O transforms to amorphous Al2O3 at a temperature of ∼180 °C, well below that of the calcination process (500 °C). This amorphous Al2O3 is highly porous with a high specific surface area, but may in turn convert to denser γ-Al2O3 and α-Al2O3 with increasing temperature. On the other hand, pure NaNO3 remains stable up to ∼880 °C, despite a solid-liquid transition at ∼320 °C. For Al(NO3)3ṡ9H2O-NaNO3 mixtures, the products of calcination at 500 °C are found to consist of very fine porous material containing Na, Al and O, in addition to a variable proportion of well-defined crystals consisting of Na, and O. Heating these mixtures to temperatures of up to 1000 °C shows that for the case 80% Al(NO3)3ṡ9H2O -20% NaNO3 (weight%) a variety of crystalline sodium aluminates is formed (NaAlO2, NaAl11O17, NaAl6O9.5), while for the 50-50 mixture, only NaAlO2 is found. In large amounts, addition of alumina thus leads to the formation of crystalline phases rich in Al2O3 that are responsible for hardening the calcine as the temperature rises. The kinetics of nitrogen loss from NaNO3 are also found to be influenced by the relative proportion of Al(NO3)3ṡ9H2O in the calcine, larger amounts of Al leading to denitration at lower temperature. These results constitute the necessary background for understanding

  3. Effect of calcination methods on electrochemical performance of NiO used as electrode materials for supercapacitor

    Indian Academy of Sciences (India)

    L Wang; X Y Qin

    2014-05-01

    Ni(OH)2 precursors were prepared via the precipitation transformation method, which was originated from Na2C2O4, NiSO4.6H2O and urea. NiO samples were successfully obtained by calcining Ni(OH)2 precursor with different calcination methods. Some were calcination in a tube furnace under the nitrogen flow and others were calcination in a muffle furnace. The products were well-characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The influence of calcination methods on electrochemical performance of NiO samples were investigated. Moreover, the possible reason was proposed. The charge storage mechanism of NiO positive electrode in aqueous electrolyte was discussed. The electrochemical test showed that the as-prepared NiO prepared in a tube furnace can exhibit a good pseudocapacitance behaviour due to the higher utilization of active material.

  4. Effect of calcination time on NiAl-Al2O3 using gel combustion synthesis method

    Science.gov (United States)

    Afandi, N. F.; Manap, A.; Yusof, S. N. A.; Salim, M. A.; Azim, M. Al.; Othman, S. Z.; Pauzi, N. I. M.; Omar, Nooririnah; Misran, H.

    2015-07-01

    This study was conducted in order to investigate the effect of calcination time on phase and microstructural characteristics of intermetallic matric composite (IMC), NiAl-Al2O3 powder. This powder was synthesized using gel combustion method with octyl alcohol as fuel. Upon completion of the combustion process, the loose powder was calcined at 1050°C for 1, 2 and 4 hours and characterized using XRD, FESEM and TEM. The crystallite size was calculated to be in the range of 29-30 nm. It was found that NiAl-Al2O3 exhibits high crystalline structure after calcination for 4 hours. Furthermore, longer calcination time also cause growth of the particle size. Findings indicate that high crystalline nanostructured NiAl-Al2O3 powder consisting of submicron particles can be successfully produced using gel combustion synthesis with longer calcination time.

  5. Extraction of potassium from K-feldspar via the CaCl2 calcination route☆

    Institute of Scientific and Technical Information of China (English)

    Bo Yuan; Chun Li; Bin Liang; Li Lü; Hairong Yue; Haoyi Sheng; Longpo Ye; Heping Xie

    2015-01-01

    The extraction of potassium from K-feldspar via a calcium chloride calcination route was studied with a focus on the effects of the calcination atmosphere, calcination temperature and time, mass ratio of CaCl2 to K-feldspar ore and particle size of the K-feldspar ore. The results demonstrated that a competing high-temperature hydrolysis reaction of calcium chloride with moisture in a damp atmosphere occurred concurrently with the conversion reaction of K-feldspar with CaCl2, thus reducing the amount of potassium extracted. The conversion reaction started at approximately 600 °C and accelerated with increasing temperature. When the temperature rose above 900 °C, the extraction of potassium gradually decreased due to the volatilization of the product, KCl. As much as approximately 41%of the potassium was volatilized in 40 min at 1100 °C. The mass ratio of CaCl2/K-feldspar ore significantly affected the extraction. At a mass ratio of 1.15 and 900 °C, the potassium extraction reached 91%in 40 min, while the extraction was reduced to only 22%at the theoretical mass ratio of 0.2. Optimal process conditions are as follows:ore particle size of 50–75μm, tablet forming pressure of 3 MPa, dry nitrogen atmosphere, mass ratio of CaCl2/ore 1.15:1, calcination temperature of 900 °C, and calcination time of 40 min. The XRD analysis revealed that a complex phase transition of the product SiO2 was also accompanied by the con-version reaction of K-feldspar/CaCl2. The SiO2 product formed at the initial stage was in the quartz phase at 900 °C and was gradually transformed into cristobalite after 30 min.

  6. Design and performance of atomizing nozzles for spray calcination of high-level wastes

    International Nuclear Information System (INIS)

    A key aspect of high-level liquid-waste spray calcination is waste-feed atomization by using air atomizing nozzles. Atomization substantially increases the heat transfer area of the waste solution, which enhances rapid drying. Experience from the spray-calciner operations has demonstrated that nozzle flow conditions that produce 70-μ median-volume-diameter or smaller spray droplets are required for small-scale spray calciners (drying capacity less than 80 L/h). For large-scale calciners (drying capacity greater than 300 L/h), nozzle flow conditions that produce 100-μ median-volume-diameter or smaller spray droplets are required. Mass flow ratios of 0.2 to 0.4, depending on nozzle size, are required for proper operation of internal-mix atomizing nozzles. Both internal-mix and external-mix nozzles have been tested at PNL. Due to the lower airflow requirements and fewer large droplets produced, the internal-mix nozzle has been chosen for primary development in the spray calciner program at PNL. Several nozzle air-cap materials for internal-mix nozzles have been tested for wear resistance. Results show that nozzle air caps of stainless steel and Cer-vit (a machineable glass ceramic) are suceptible to rapid wear by abrasive slurries, whereas air caps of alumina and reaction-bonded silicon nitride show only slow wear. Longer-term testing is necessary to determine more accurately the actual frequency of nozzle replacement. Atomizing nozzle air caps of alumina are subject to fracture from thermal shock, whereas air caps of silicon nitride and Cer-vit are not. Fractured nozzles are held in place by the air-cap retaining ring and continue to atomize satisfactorily. Therefore, fractures caused by thermal shocking do not necessarily result in nozzle failure

  7. Design and performance of atomizing nozzles for spray calcination of high-level wastes

    Energy Technology Data Exchange (ETDEWEB)

    Miller, F.A.; Stout, L.A.

    1981-05-01

    A key aspect of high-level liquid-waste spray calcination is waste-feed atomization by using air atomizing nozzles. Atomization substantially increases the heat transfer area of the waste solution, which enhances rapid drying. Experience from the spray-calciner operations has demonstrated that nozzle flow conditions that produce 70-..mu.. median-volume-diameter or smaller spray droplets are required for small-scale spray calciners (drying capacity less than 80 L/h). For large-scale calciners (drying capacity greater than 300 L/h), nozzle flow conditions that produce 100-..mu.. median-volume-diameter or smaller spray droplets are required. Mass flow ratios of 0.2 to 0.4, depending on nozzle size, are required for proper operation of internal-mix atomizing nozzles. Both internal-mix and external-mix nozzles have been tested at PNL. Due to the lower airflow requirements and fewer large droplets produced, the internal-mix nozzle has been chosen for primary development in the spray calciner program at PNL. Several nozzle air-cap materials for internal-mix nozzles have been tested for wear resistance. Results show that nozzle air caps of stainless steel and Cer-vit (a machineable glass ceramic) are suceptible to rapid wear by abrasive slurries, whereas air caps of alumina and reaction-bonded silicon nitride show only slow wear. Longer-term testing is necessary to determine more accurately the actual frequency of nozzle replacement. Atomizing nozzle air caps of alumina are subject to fracture from thermal shock, whereas air caps of silicon nitride and Cer-vit are not. Fractured nozzles are held in place by the air-cap retaining ring and continue to atomize satisfactorily. Therefore, fractures caused by thermal shocking do not necessarily result in nozzle failure.

  8. Alliance between chemical industry Astral Calcining, India, and energy company E.On Benelux; Verbond chemie en energie [tussen Astral Calcining, India en E.On Benelux

    Energy Technology Data Exchange (ETDEWEB)

    Roggen, M. (ed.)

    2003-03-01

    The Indian chemical concern Astral Calcining (produces carbon for the aluminium industry) will supply high-pressure steam to the energy company E.ON Benelux, to be used by Lyondell Bayer (producer of propylene oxide). In exchange, Astral will receive electricity from E.On Benelux. This is a unique co-operation between companies with different production processes and cultures. [Dutch] Het Indiase chemieconcern Astral gaat aan E.ON Benelux hogedruk stoom leveren die bestemd is voor Lyondell Bayer. In ruil daarvoor ontvangt Astral elektriciteit. Een unieke samenwerking tussen concerns met totaal andere productieprocessen en uiteenlopende culturen.

  9. Influence of the Calcination Temperature on the Combustion Synthesized Perovskite LaMnO3 Compound

    Directory of Open Access Journals (Sweden)

    A.R. Shelke

    2015-10-01

    Full Text Available A simple combustion method based on principles of propellent chemistry in which Polyvinyl alcohol (PVA as fuel and nitrates as oxidizer were used for synthesizing the perovskite like LaMnO3 powders. The oxidizer to fuel ratio was maintained at 5 : 1. The darkish black powder obtained was calcined at 800 °C and 1000 °C for 5 hour. The combustion and thermal decomposition of the precursor were investigated using the TG-DTA and Fourier Transform Infra-Red (FT-IR techniques. The X-ray diffraction (XRD pattern of all three samples i.e., un-heated LaMnO3 powder (LMO-UH, calcined at 800 °C (LMO-800 and at 1000 °C (LMO-1000 were carried out. The single phase orthorhombic crystal structure was revealed to crystallize at LMO-800 and LMO-1000 with elevation in the crystalline size. A small impurity peak at 28.7° was seen of Mn3O4 for LMO-UH, which vanished after calcining it. The strong absorption in FT-IR spectra found at around 615 cm – 1 was due to the formation of metal-oxygen (M-O bond. Moreover a small shift in this M-O bond with increase in calcination temperature suggested the strained LaMnO3 compound. Elemental analysis using the energy dispersive X-ray fluorescence spectrometer (EDXRF indicated the presence of La and Mn with increase in the Mn contents after calcinations. The oxygen, nitrogen and hydrogen content in the sample were determined from the ONH analysis indicating a decrease in the oxygen content for LMO-800. Well defined porous-foam like morphology of the sample was achieved from scanning electron microscopic (SEM study, which become compact with calcination process. Magnetic properties were found to transform from the ferromagnetic-to-paramagnetic phase for LMO-UH sample, while reduction in magnetization values and coercivity at low temperatures was obtained for LMO-800 and LMO-1000 samples.

  10. Influence of calcination on the adsorptive removal of phosphate by Zn-Al layered double hydroxides from excess sludge liquor

    International Nuclear Information System (INIS)

    The influence of calcination of Zn-Al layered double hydroxides (LDHs) on their phosphate adsorption capacity was studied in order to improve phosphorus removal from an excess sludge liquor. Powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), thermogravimetry-differential scanning calorimetry (TG-DSC) and nitrogen adsorption-desorption were employed to characterize the raw Zn-Al and the calcined products. The results reveal that the Zn-Al LDHs evolved to a phase of mixed metal oxides with the calcination temperature increasing to 300 deg. C and finally to spinel ZnAl2O4 at 600 deg. C. When the Zn-Al was calcined at 300 deg. C, the interlayer carbonate ions were removed and the greatest BET surface area of 81.20 m2/g was achieved. The tested phosphate adsorption capacities of the raw and calcined Zn-Al were closely related to the evolution of physicochemical properties of the LDHs during the calcination. The Zn-Al-300 (Zn-Al LDHs calcined at 300 deg. C) exhibited the highest P uptake of 41.26 mg P/g in 24 h. The phosphate adsorption by the raw Zn-Al and the Zn-Al-300 both follows a pseudo-second-order kinetic model; the adsorption isotherms show a good fit with a Langmuir-type equation.

  11. Influence of calcination on the adsorptive removal of phosphate by Zn-Al layered double hydroxides from excess sludge liquor

    Energy Technology Data Exchange (ETDEWEB)

    Cheng Xiang, E-mail: sean.d.cheng@gmail.com [School of Municipal and Environmental Engineering, Harbin Institute of Technology, 202 Haihe Road, 150090 Harbin (China); Huang Xinrui [School of Municipal and Environmental Engineering, Harbin Institute of Technology, 202 Haihe Road, 150090 Harbin (China); Wang Xingzu; Sun Dezhi [College of Environmental Science and Engineering, Beijing Forestry University, 35 Tsinghua East Road, 100083 Beijing (China)

    2010-05-15

    The influence of calcination of Zn-Al layered double hydroxides (LDHs) on their phosphate adsorption capacity was studied in order to improve phosphorus removal from an excess sludge liquor. Powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), thermogravimetry-differential scanning calorimetry (TG-DSC) and nitrogen adsorption-desorption were employed to characterize the raw Zn-Al and the calcined products. The results reveal that the Zn-Al LDHs evolved to a phase of mixed metal oxides with the calcination temperature increasing to 300 deg. C and finally to spinel ZnAl{sub 2}O{sub 4} at 600 deg. C. When the Zn-Al was calcined at 300 deg. C, the interlayer carbonate ions were removed and the greatest BET surface area of 81.20 m{sup 2}/g was achieved. The tested phosphate adsorption capacities of the raw and calcined Zn-Al were closely related to the evolution of physicochemical properties of the LDHs during the calcination. The Zn-Al-300 (Zn-Al LDHs calcined at 300 deg. C) exhibited the highest P uptake of 41.26 mg P/g in 24 h. The phosphate adsorption by the raw Zn-Al and the Zn-Al-300 both follows a pseudo-second-order kinetic model; the adsorption isotherms show a good fit with a Langmuir-type equation.

  12. JC properties and microstructures of YBCO films fabricated by low temperature calcination in TFA-MOD method

    International Nuclear Information System (INIS)

    YBa2Cu3O7-δ (YBCO) films were grown on LaAlO3 substrates by a metal organic deposition using trifluoroacetates (TFA-MOD). In this study, effects of calcination condition such as temperature on microstructures and Jc properties for the YBCO films were studied. The TFA starting solution was coated on a substrate by a spin-coating method. Then, a two-step heat treatment was applied to the coated films. In the calcination step, the coated film was calcined to form a homogeneous amorphous precursor by increasing the temperature which was varied from 300 deg. C to 500 deg. C at a constant heating rate of 2 deg. C/min. The prepared precursor films were crystallized at a constant condition. As a result, Jc value depended on the calcination temperature, YBCO film calcined at 400 deg. C showed the highest Jc of 2.5 MA/cm2. Jc's for the YBCO films calcined at 300 deg. C and 350 deg. C were 1.9 MA/cm2 and 2.0 MA/cm2, respectively. On the other hand, YBCO film calcined at 500 deg. C showed the lowest Jc of 1.4 MA/cm2. Cross-sectional TEM images showed that the YBCO film calcined at 400 deg. C had less pores and small size of pores in the crystallized film randomly throughout the film. Large pores were observed in the YBCO film calcined at 500 deg. C. Also, these large pores were existed near substrate in the YBCO film. It is considered that the differences of these pore formation mechanisms are the main cause of the difference of Jc characteristic.

  13. EFFECT OF CALCINATION TEMPERATURE OF TUNISIAN CLAYS ON THE PROPERTIES OF GEOPOLYMERS

    Directory of Open Access Journals (Sweden)

    Essaidi N.

    2013-09-01

    Full Text Available Geopolymers are amorphous three dimensional aluminosilicate materials that may be synthesized at room or slightly higher temperature by alkaline activation of aluminosilicates obtained from industrial wastes, calcined clays and natural minerals. Among the different family of geopolymers, two Tunisian clays (a kaolinite clay from Tabarka and illito/kaolinitic clay from Medenine are tested for their feasibility of geopolymers at low temperature. The unfired and calcined clays were dissolved in strongly alkaline solution in order to produce consolidated materials whose pastes were characterized by their compressive strength. Hardened geopolymer samples were also submitted to X-Ray diffraction, FTIR spectroscopy and scanning electron microscopy analyses. The geopolymer strength is related to the structure and reactivity of the clay generated by thermal treatment and to the role of associated minerals in clays. The amorphous character of obtained geopolymers and the displacement of the IR wavenumber are signature of geopolymerisation reaction.

  14. Influence of Calcination on the Physical Characteristics and Nitrogen Removal Performance of Clinoptilolites

    Institute of Scientific and Technical Information of China (English)

    LIN Hai; JIN Xin; DONG Yingbo; HUO Hanxin; LIU Quanli

    2014-01-01

    The influences of roasting activation on the particle morphology, microscopic structure, and adsorption properties of natural clinoptilolites were investigated. The experimental results show that the optimal modified conditions include a calcination temperature at 400℃, a roasting time of 0.5 h, and furnace cooling. The ammonia nitrogen removal rate from analog renewable water of the modified clinoptilolites reached 72%in the optimized conditions, which is 12%higher than that of natural ones. Scanning electron microscopy analysis showed that the surface morphology changed, the micro-hole size increased, and the surface became smoother and more uniform after calcination. The single-point total adsorption average pore width increased from 7.74 nm to 10.64 nm.

  15. Effect of Reaction Rate and Calcination Time on CaNb2O6 Nanoparticles

    Directory of Open Access Journals (Sweden)

    C. M. Dudhe

    2014-01-01

    Full Text Available The properties of CaNb2O6 nanoparticles synthesized by coprecipitation method under controlled reaction rate and extended calcination time were studied. Analysis of the X-ray diffraction pattern shows single orthorhombic phase of the material with lattice parameters: a=15.0147 Å, b=5.74148 Å, and c=5.30296 Å. The morphology and size of particles was found to be improved due to the controlled reaction rate and extended calcination time. The average sizes of the particles were estimated as 40 nm and 90 nm for sintering temperatures 650°C and 800°C, respectively. The material was found to possess dielectric constant which is inversely proportional to the frequency. Surprisingly, the material shows ferroelectric behavior, the possible origin of which is discussed here.

  16. Separation of Zinc from High Iron-Bearing Zinc Calcines by Reductive Roasting and Leaching

    Science.gov (United States)

    Peng, Bing; Peng, Ning; Min, Xiao-Bo; Liu, Hui; Li, Yanchun; Chen, Dong; Xue, Ke

    2015-09-01

    This paper focuses on the selective leaching of zinc from high iron-bearing zinc calcines. The FactSage 6.2 program was used for the thermodynamic analysis of the selective reduction and leaching, and the samples reduced by carbon and carbon monoxide were subjected to acid leaching for the separation of zinc from iron. It is shown that the generation of ferrous oxide should be avoided by modifying V CO ( P CO/( P CO + )) in the roasting process prior to the selective leaching of zinc. Gaseous roasting-leaching has a higher efficiency in the separation of zinc from iron than carbothermic reduction-leaching. The conversion of the zinc ferrite in high iron-bearing zinc calcines to zinc oxide and magnetite has been demonstrated by x-ray diffraction (XRD) and magnetic hysteresis loop characterization. This gaseous roast-leach process is technically feasible to separate zinc from iron without an iron precipitation process.

  17. Evaluation and selection of aqueous-based technology for partitioning radionuclides from ICPP calcine

    International Nuclear Information System (INIS)

    Early in 1993 Westinghouse Idaho Nuclear Company (WINCO) chartered a Panel of Nuclear Separations Experts. The purpose of this Panel was to assist WINCO scientists and engineers in selecting, evaluating, and ranking candidate aqueous-based processes and technologies for potential use in partitioning selected radionuclides from nitric acid solutions of retrieved Idaho Chemical Processing Plant (ICPP) calcine. Radionuclides of interest are all transuranium elements, 90Sr, 99Tc, 129I, and 137Cs. The six man Panel met for 4 days (February 16--19, 1993) on the campus of the Idaho State University in Pocatello, Idaho. Principal topics addressed included: Available radionuclide removal technology; applicability of separations technology and processes to ICPP calcine; and potential integrated radionuclide partitioning schemes. This report, prepared from contributions from all Panel members, presents a comprehensive account of the proceedings and significant findings of the February, 1993 meeting in Pocatello

  18. Ethanol Total Oxidation Over Calcined Layered Double Hydroxides Modified with Organic Components

    Directory of Open Access Journals (Sweden)

    Kovanda, F.

    2013-05-01

    Full Text Available Coprecipitation of Co, Mn, and Al nitrates by a solution of Na2CO3 and NaOH in the presence of Pluronic ® P123 has led to layered double hydroxide (LDH precursors with hydrotalcite-like structure. Their calcination gave spinel-type mixed oxides; the presence of organic template increased both BET and mesopore surface areas of the calcined products. TPR profiles of the samples modified with Pluronic ® P123 exhibited a shift of reduction maxima to lower temperatures, similarly as increasing sodium content in the catalysts. However, though the physical-chemical properties of Co-Mn-Al mixed oxides and their catalytic activity in ethanol oxidation were slightly improved, the changes evolved by the presence of Pluronic ® P123 during precipitation of LDH precursors were rather small.

  19. Conceptual design for remote handling methods using the HIP process in the Calcine Immobilization Program

    International Nuclear Information System (INIS)

    This report recommends the remote conceptual design philosophy for calcine immobilization using the hot isostatic press (HIP) process. Areas of remote handling operations discussed in this report include: (1) introducing the process can into the front end of the HIP process, (2) filling and compacting the calcine/frit mixture into the process can, (3) evacuating and sealing the process can, (4) non-destructive testing of the seal on the process can, (5) decontamination of the process can, (6) HIP furnace loading and unloading the process can for the HIPing operation, (7) loading an overpack canister with processed HIP cans, (8) sealing the canister, with associated non-destructive examination (NDE) and decontamination, and (9) handling canisters for interim storage at the Idaho Chemical Processing Plant (ICPP) located on the Idaho National Engineering Laboratory (INEL) site

  20. Preparation of ITO nano-powders by hydrothermal-calcining process

    Institute of Scientific and Technical Information of China (English)

    GU Ying-ying; QIN Li-ping; LIU Xue-ying

    2006-01-01

    Sn-doped In2O3 (ITO) nano-powders were prepared by hydrothermal-calcining process. Using SnCl4·5H2O and In as starting materials, the crystallites were characterized by XRD, TEM and BET. The effects of the conditions on the product were investigated. The results show that the phase of hydrothermal precursor obtained by hydrothermal process is related to the temperature of hydrothermal reaction, I. E. , the phases are amorphous In(OH)3 in 160 - 180℃; In(OH)3 crystal in 200℃ and (In1-xSnx)OOH crystal in 200 - 300℃. ITO nano-powders with hexagonal structure and average size of 65 nm are obtained by calcining the precursor derived from the hydrothermal process at 350 - 650℃. The BET of ITO crystal can reach 84. 023 4 m2·g-1.

  1. Various durability aspects of calcined Kaolin-blended Portland cement pastes and concretes

    OpenAIRE

    SAILLIO, Mickael; BAROGHEL BOUNY, Véronique; PRADELLE, Sylvain

    2015-01-01

    The use of calcined clay, in the form of metakaolin (MK), as a pozzolanic constituent for concrete has received considerable attention in recent years, due to the lower CO2 emission of this supplementary cementitious material compared to the production of a classic portland cement. Furthermore, concretes incorporating MK show some improve durability properties. In this paper, the durability of concretes and cement pastes with MK as partial replacement of cement (10 and 25%) has been investiga...

  2. Early and Late Strength Characterization of Portland Cement Containing Calcined Low-Grade Kaolin Clay

    OpenAIRE

    Mark Bediako; Gawu, S. K. Y.; A. A. Adjaottor; John Solomon Ankrah

    2016-01-01

    Heat treated low-grade kaolin clays are now considered as a suitable pozzolanic material to metakaolins. However their suitability as a good pozzolanic material depends on the geochemistry and structure of the clay which is usually influenced by the geographical environment. This study investigated a low-grade kaolin clay from Nyamebekyere in the Ashanti Region of Ghana. The influence of the calcined material on the early and late strength development of Portland cement was analyzed. The earl...

  3. In-situ investigation of the calcination process of mixed oxide xerogels with Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Panitz, J.C. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    The controlled calcination of materials derived by sol-gel reactions is important for the evolution of the final structure. Raman spectroscopy is an ideal tool for the identification of surface species under in-situ conditions, as demonstrated in the following for the example of a molybdenum oxide-silica xerogel. Raman spectra of this particular sample were recorded at temperatures as high as 1173 K, and compared with those of a reference material.(author) 3 figs., 4 refs.

  4. Rotary Calciner - Metallic Melter and Slurry - Fed Ceramic Melter for Treatment of High Level Liquid Waste

    International Nuclear Information System (INIS)

    Rotary calciner-metallic melter and slurry-fed ceramic melter are used for treatment of high level liquid waste in the industrial scale. Rotary calciner-metallic melter is operated by induction heating and slurry-fed ceramic melter by Joule heating. Both of melter are compared it’s characteristics of waste-glass composition for process and melter operation, melter materials, life time of melter, treatment of off gas, and power consumption. For melter with Joule heating, electric resistance of waste-glass is 4.8 ohm.cm at temperature 1150 °C. The metal of platinum group is not soluble in the molten waste-glass, so that influence the electric current pass by the molten waste-glass. For melter with induction heating there is not influence of platinum metal group. For melter with Joule heating, the material which contact with waste-glass is monofrax K-3. The outer materials layer i.e MRT-70K, LN-135, AZ-GS, fiber board, and stainless steel 304. The material of melter with induction heating is Inconel-690. The life time of melter with Joule heating is longer than melter with induction heating. From the safety aspect, operation of the both of melter have already successful. Operation cost of slurry-fed ceramic melter is cheaper, but construction and decommissioning cost more expensive than rotary calciner-metallic melter. Based on Indonesia condition, the slurry-fed ceramic melter is more reasonable to be utilized. (author)

  5. Removal of nickel on Bofe bentonite calcined clay in porous bed

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, M.G.A.; Neto, A.F. Almeida [UNICAMP/FEQ/DTF, Campinas, SP (Brazil); Gimenes, M.L. [UEM/CTC/DEQ, Campinas, SP (Brazil); Silva, M.G.C. da, E-mail: meuris@feq.unicamp.br [UNICAMP/FEQ/DTF, Campinas, SP (Brazil)

    2010-04-15

    Bentonite clays have been showing good adsorbing characteristics and are used as an alternative material in the removal of heavy metals. The purpose of this study is to evaluate the removal of nickel on Bofe bentonite calcined clay in porous bed. Firstly, a study was conducted to define the operation outflow, based on the minimum mass transfer zone (MTZ) obtained, useful (q{sub U}) and total adsorbed (q{sub T}) removal amounts and total nickel removal percentage (Rem (%)). Assays of nickel adsorption on clay were conducted according to a 2{sup 2} factorial design with three central points to evaluate the effect of the particle diameter and initial adsorbate concentration on variables q{sub U}, q{sub T} and Rem (%). Tests to obtain the adsorbent physical and chemical characteristics were performed on samples of Bofe clay in natura, calcined, and calcined submitted to nickel adsorption. This clay was characterized according to the following techniques: Energy Dispersive Spectroscopy (EDS), Thermogravimetry (TG), Differential Scanning Calorimetry (DSC), X-ray Diffraction (XRD), Fourier Transformed Infrared Spectroscopy (FTIR), Physisorption of N{sub 2} (BET), Helium Picnometry and Scanning Electron Microscope (SEM) with metal mapping.

  6. Oxyfuel carbonation/calcination cycle for low cost CO2 capture in existing power plants

    International Nuclear Information System (INIS)

    Postcombustion CO2 capture is the best suitable capture technology for existing coal power plants. This paper focuses on an emerging technology that involves the separation of CO2 using the reversible carbonation reaction of CaO to capture CO2 from the flue gas, and the calcination of CaCO3 to regenerate the sorbent and produce concentrated CO2 for storage. We describe the application to this concept to an existing (with today's technology) power plant. The added capture system incorporates a new supercritical steam cycle to take advantage of the large amount of heat coming out from the high temperature capture process (oxyfired combustion of coal is needed in the CaCO3 calciner). In these conditions, the capture system is able to generate additional power (26.7% efficiency respect to LHV coal input to the calciner after accounting for all the penalties in the overall system), without disturbing the steam cycle of the reference plant (that retains its 44.9 efficiency). A preliminary cost study of the overall system, using well established analogues in the open literature for the main components, yields capture cost around 16 Euro /ton CO2 avoided and incremental cost of electricity of just over 1 Euro /MW h e

  7. Effect of calcination temperature on the synthesis of potassium titanate with platy morphology

    International Nuclear Information System (INIS)

    The dramatic increases in the number of pneumoconiosis cases have stimulated the search of new materials for replacement of asbestos fibers. Titanate plates with formula AyTi2-xMxO4, where A = K, Rb, Cs and M = Li, Mg, Co, Ni, Cu, Zn, Mn (III), Fe (III) have been studied as an alternative for the use of fibers. The effect of the variation of calcination temperature on the reaction of K2CO3-TiO2-Mg(OH)2 system was studied with the aim of understanding the relationship of this parameter with the morphology and symmetry of the obtained plates. For this study the samples were calcined for 5 hours at temperatures of 950°C, 1000°C, 1050°C and 1100°C. The powders were analyzed by X-ray diffraction and scanning electron microscopy. It was concluded that 1000°C is the better calcination temperature for obtaining more symmetric plates with smaller particle size dispersion. (author)

  8. High-level waste vitrification by spray calcination/in-can melting

    Energy Technology Data Exchange (ETDEWEB)

    Larson, D.E.; Bonner, W.F. (comp.)

    1976-11-01

    Federal regulations require that high-level liquid waste (HLLW) be converted to a solid for custody in a Federal repository. The Spray Solidification/In-Can Melting process has been developed and is being demonstrated for commercial application. The bases used are similar to those of the NFS plant and to anticipated regulations for waste canister receipt at a Federal repository. The reference NFS flowsheet combines plant HA Column Wastes, Low-Level Wastes, and various HLLW process recycle streams to produce a borosilicate glass. After the canister is filled and sealed, the lid weld will be inspected and decontaminated. Equipment and instrumentation for feed supply to the calciner, calcination, melting, welding, weld inspection, canister decontamination, and in-cell canister storage are being designed and demonstrated. Preliminary facility layouts, equipment design data, and instrumentation needs are provided for major process equipment systems. Additional demonstration work is being performed to verify and complete the plant scale equipment design, including full-scale nonradioactive equipment testing, nonradioactive facility mockup for equipment remote operation and maintenance demonstration, and pilot plant production of waste glass from commercial fuel HLLW. The technology for spray calcination and in-can melting is ready for commercial application. Required additional work is described. A preliminary evaluation is made of materials that may be released from the process from normal and abnormal operations in the facility. 34 figures, 20 tables. (DLC)

  9. Synthesis and luminescence of Eu3+ doped hydroxyapatite nanocrystallines: Effects of calcinations and Eu3+ content

    International Nuclear Information System (INIS)

    Eu3+ doped hydroxyapatite (Eu-HAP) luminescent nanocrystallines were prepared by ultrasound assisted precipitation method. Aiming to seek a compromise proposal for achieving high luminescence and nanocrystallines, the effects of calcinations temperature and Eu3+ doping content on luminescence property as well as phase composition, crystal size and crystallinity of Eu-HAP crystals were investigated. The results showed that the luminescence of Eu-HAP was enhanced by the thermal treatment and the increasing Eu doping content. However, the higher temperature and the excess Eu resulted in the size increase and phase composition change of HAP respectively. The 2% Eu doping content and calcinations temperature of 600 °C were preferred for preparing Eu-HAP nanocrystallines with strong luminescence. The Eu-HAP nanocrystallines were about 20–40 nm in diameter (TEM) and could be well dispersed in water to form aqueous suspension of about 140 nm (DLS intensity-averaged diameter). Eu-HAP nanocrystalline could be used as a fluorescent probe for cell labeling. - Highlights: ► 20–40 nm Eu-HAP luminescent nanocrystallines were prepared by the precipitation method. ► 2% Eu doping content and calcinations at 600 °C were preferred to prepare Eu-HAP. ► Eu-HAP nanocrystallines could be well dispersed to form aqueous suspension. ► Eu-HAP nanocrystallines could be used as cell labels.

  10. Mobile calcination and cementation unit for solidification of concentrated radioactive wastes

    International Nuclear Information System (INIS)

    Mobile experimental unit MESA-1 was developed and manufactured for processing radioactive concentrates by direct cementation. The unit is mainly designed for processing low-level liquid wastes from nuclear power plants and other nuclear installations, in which the level of radioactivity does not exceed 1010 Bq/m3, the salt content of liquid solutions does not exceed 500 kg/m3 and the maximum amount of boric acid is 130 kg/m3. The equipment is built into three modules which may be assembled and dismantled in a short time and transported separately. The unit without the calciner module was tested in non-radioactive mode and in operation with actual radioactive wastes from the V-1 nuclear power plant. The course and results of the tests are described in detail. All project design values were achieved, a total of 18 dm3 model solutions were processed and 1 m3 of actual wastes with a salt content of 450 kg/m3. The test showed that with regard to the radiation level reached it will be necessary in the process of calcination to increase the shielding of certain exposed points. The calciner module is being assembled for completion. (Z.M.)

  11. Processing of concentrated radioactive wastes into cement and bitumens following calcination

    International Nuclear Information System (INIS)

    A brief characteristic is presented of the most frequently used processes of solidification of liquid radioactive wastes, viz., bituminization, cementation and their combination with calcination. The effect of individual parameters is assessed on the choice of the type of solidification process as is their importance in the actual process, in temporary storage, during transportation and under conditions of long-term storage. It has been found that a combination of the procedures could lead to a modular system of methods and equipment. This would allow to approach optimal solidification of wastes in the present period and to establish a research reserve for the development of more modern, economically advantageous and safer procedures. A rough estimate is made of the costs of the solidification of 1 m3 of radioactive concentrate from the V-1 power plant at a production of 380 m3/year, this for the cementation-calcination and bituminization-calcination procedures. The said rough economic analysis only serves to identify the major operating components which have the greatest effect on the economic evaluation of the solidification procedures. (Z.M.)

  12. Test plan for radioactive testing of a vertical direct denitration calciner

    International Nuclear Information System (INIS)

    The prototype Vertical Denitration Calciner (VDC) is installed in glovebox 188 in the Plutonium Process Support Laboratory (PPSL). Safety analysis contained in WHC-SD-CP-SAR-021 (FSAR) Rev. 0-L and Addendum to WHC-SD-CP-SAR-021, ''Laboratory Prototype Calciner'' establishes the prototype VDC needs to be shut down if a seismic event of greater than 0.07 g occurs. Shut down is to be automatic upon detection of the seismic event. This requires tie-in of various valves and power for the prototype VDC into the existing Seismic Shutdown System for the Ventilation Supply Fans described in FSAR 5.4.1.2.4. The proposed changes covered by this USQ evaluation include: (1) the physical tie-in modifications, including drawings and Engineering Change Notice (ECN), (2) the work package for accomplishing the modifications, (3) the changes to the System Description Documents, (4) the changes to the Safety Equipment List necessitated by the modifications, and (5) the changes to the failure modes and effects analysis. WHC-SDCP-OSR-010, Plutonium Finishing Plant Operational Safety Requirements Limiting Condition for Operation (LCO) 3.2.3 has been revised to include the requirement for the existing seismic shutdown system to also shut down the laboratory calciner in the event of detection of a greater than 0.07 g seismic event

  13. Test Plan for Radioactive Testing of a Vertical Direct Denitration Calciner

    International Nuclear Information System (INIS)

    The prototype Vertical Denitration Calciner (VDC) is installed in glovebox 188 in the Plutonium Process Support Laboratory (PPSL). Safety analysis contained in WHC-SD-CP-SAR-021 (FSAR) Rev. 0-L and Addendum to WHC-SD-CP-SAR-021, ''Laboratory Prototype Calciner'' establishes the prototype VDC needs to be shut down if a seismic event of greater than 0.07 g occurs. Shut down is to be automatic upon detection of the seismic event. This requires tie-in of various valves and power for the prototype VDC into the existing Seismic Shutdown System for the Ventilation Supply Fans described in FSAR 5.4.1.2.4. The proposed changes covered by this USQ evaluation include: (1) the physical tie-in modifications, including drawings and Engineering Change Notice (ECN), (2) the work package for accomplishing the modifications, (3) the changes to the System Description Documents, (4) the changes to the Safety Equipment List necessitated by the modifications, and (5) the changes to the failure modes and effects analysis. WHC-SDCP-OSR-010, Plutonium Finishing Plant Operational Safety Requirements Limiting Condition for Operation (LCO) 3.2.3 has been revised to include the requirement for the existing seismic shutdown system to also shut down the laboratory calciner in the event of detection of a greater than 0.07 g seismic event

  14. DECONTAMINATION OF PLUTONIUM FOR FLUORIDE AND CHLORIDE DURING OXALATE PRECIPITATION, FILTRATION AND CALCINATION PROCESSES

    Energy Technology Data Exchange (ETDEWEB)

    Kyser, E.

    2012-07-25

    Due to analytical limitations for the determination of fluoride (F) and chloride (Cl) in a previous anion exchange study, an additional study of the decontamination of Pu from F and Cl by oxalate precipitation, filtration and calcination was performed. Anion product solution from the previous impurity study was precipitated as an oxalate, filtered, and calcined to produce an oxide for analysis by pyrohydrolysis for total Cl and F. Analysis of samples from this experiment achieved the purity specification for Cl and F for the proposed AFS-2 process. Decontamination factors (DF's) for the overall process (including anion exchange) achieved a DF of {approx}5000 for F and a DF of {approx}100 for Cl. Similar experiments where both HF and HCl were spiked into the anion product solution to a {approx}5000 {micro}g /g Pu concentration showed a DF of 5 for F and a DF of 35 for Cl across the combined precipitation-filtration-calcination process steps.

  15. Improvement of the crystallinity and photocatalytic property of zinc oxide as calcination product of Zn-Al layered double hydroxide

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Abdullah Ahmed Ali [Department of Physics, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Talib, Zainal Abidin, E-mail: zainalat@science.upm.edu.my [Department of Physics, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Hussein, Mohd Zobir bin [Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Advanced Materials and Nanotechnology Laboratory, Institute of Advanced Technology (ITMA), Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Zakaria, Azmi [Department of Physics, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Advanced Materials and Nanotechnology Laboratory, Institute of Advanced Technology (ITMA), Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia)

    2012-10-25

    Highlights: Black-Right-Pointing-Pointer ZnO phase and ZnAl{sub 2}O{sub 4} spinel can be formed as Zn-Al-NO{sub 3}-LDH calcination products. Black-Right-Pointing-Pointer The crystallinity of ZnO phase increased with an increase of calcination temperature. Black-Right-Pointing-Pointer The optical band gaps of ZnO were improved with an increase in temperature. Black-Right-Pointing-Pointer The oxygen vacancies in ZnO and ZnAl{sub 2}O{sub 4} generated the ESR signals. - Abstract: Zinc oxide with different degrees of crystallinity can be formed as Zn-Al-layered double hydroxide (Zn-Al-NO{sub 3}-LDH) calcination products. ZnAl{sub 2}O{sub 4} spinel is also formed in a range of calcination temperatures from 600 to 1000 Degree-Sign C from the LDH. X-ray diffraction patterns showed that the crystallinity of the ZnO phase increased as calcination temperatures increased. The LDH structure was fully collapsed at and above 400 Degree-Sign C. The photocatalytic activity was determined by UV-VIS-NIR diffuse reflectance spectroscopy. The band gap of the calcined samples increased as the calcination temperature increased. Electron spin resonance (ESR) spectra of the fresh and calcined LDH at room temperature demonstrated that oxygen vacancies in the ZnO and ZnAl{sub 2}O{sub 4} were responsible for the generation of ESR signals. One BET specific surface area increased from 1 m{sup 2}/g for the LDH to a maximum at 400 Degree-Sign C (43 m{sup 2}/g) and decreased thereafter down to 6 m{sup 2}/g at 1000 Degree-Sign C.

  16. Analysis of the reusability of the energy of the exhaust gas from the calciner for the production of carbon

    International Nuclear Information System (INIS)

    A calciner is used to produce carbon from anthracite coal. In its working process, a significant amount of energy is lost through its exhaust gas. How much energy can be recovered from the exhaust gas becomes important. To answer this question a method to determine the mass flow rate and the composition of the exhaust gas from a calciner is developed, and a combustion model based on well-stirred reactor is used to obtain the suitable combustor parameters and the amount of the chemical energy which can be released in combustion. As an example to verify the method and the model, the energy utilization ratio of a calciner with power of 1250 kW is investigated. The results show that the method can determine the mass flow rate and the composition of the exhaust gas, and the combustion model is suitable for obtaining reasonable results in determining the volume and the heat duty of the combustor, the air–fuel ratio, and the amount of the chemical energy released. For a calciner with power of 1250 kW, when the temperature of the tail gas after combustion reaches to 135 °C, the energy utilization ratio of the calciner is calculated to be around 77%. - Highlights: • A method obtaining the mass balance of exhaust gas from calciner is reported. • A combustion model obtaining combustion behavior of the exhaust gas is reported. • Determining the energy utilization ratio of a typical calciner is demonstrated. • The energy utilization ratio of a typical calciner is about 77%

  17. The Effect of Calcination Temperature on Structure and Photocatalytic Properties of WO3/TiO2 Nanocomposites

    Directory of Open Access Journals (Sweden)

    Joanna Mioduska

    2016-01-01

    Full Text Available Series of WO3/TiO2 nanocomposites were obtained by hydrothermal method followed by calcination in the temperature range from 400°C to 900°C. The characteristics of photocatalysts by X-ray diffractometry (XRD, scanning electron microscope (SEM, and diffuse reflectance spectroscopy (DRS showed that increasing the calcination temperature from 400 to 900°C resulted in change of photocatalytic activity under UV-Vis light. Moreover, the amount of WO3 crystalline phase and amorphous phase in WO3/TiO2 aggregates, as revealed by XRD analysis, was dependent on the calcination temperature. The WO3/TiO2 samples with 8 mol% load of WO3 in respect to TiO2 calcinated at 500 and 800°C possess the highest photocatalytic activity in reaction of phenol degradation, which is about 1.2 and 1.5 times that with calcination at 400°C. The increase in calcination temperature above 400°C resulted in increase of WO3 crystallinity and reduction of the amount of amorphous phase in the nanocomposite structure. Moreover, the annealing of nanocomposites above 700°C decreases the value of optical band gap energies of obtained WO3/TiO2 nanomaterials.

  18. Effect of calcination temperature on structural properties and photocatalytic activity of Mn-C-codoped TiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Jianbo; Xin, Wei; Liu, Guanglong; Lin, Die; Zhu, Duanwei, E-mail: liugl@mail.hzau.edu.cn [Laboratory of Eco-Environmental Engineering Research, College of Resources and Environment, Huazhong Agricultural University (HZAU), Wuhan (China)

    2016-03-15

    Mn-C-codoped TiO{sub 2} catalysts were synthesized by modified sol-gel method based on the self-assembly technique using polyoxyethylene sorbitan monooleate (Tween 80) as template and carbon precursor and the effect of calcination temperature on their structural properties and photocatalytic activity were investigated. The XRD results showed undoped and Mn-C-codoped TiO{sub 2} calcined at 400 deg C only include anatase phase and the rutile phase appears when the calcination temperature reached to 600 deg C. UV-vis absorption spectroscopy demonstrates that the absorption spectra are strongly modified by the calcination temperature. Moreover, the Mn-C-TiO{sub 2} calcined at 400 deg C showed the lowest PL intensity due to a decrease in the recombination rate of photogenerated electrons and holes under light irradiation. The photocatalytic activity of Mn-C-codoped TiO{sub 2} were evaluated by the degradation of methyl orange (MO) under the simulate daylight irradiation and all the prepared Mn-C-codoped TiO{sub 2} samples exhibited high photocatalytic activities for photocatalytic decolorisation of methyl orange aqueous solution. At 400 deg C, the Mn-C-codoped TiO{sub 2} samples showed the highest photocatalytic activity due to synergetic effects of good crystallize ation, appropriate phase composition and slower recombination rate of photogenerated charge carriers, which further confirms the calcination temperature could affect the properties of Mn-C-codoped TiO2 significantly. (author)

  19. The variation of cationic microstructure in Mn-doped spinel ferrite during calcination and its effect on formaldehyde catalytic oxidation.

    Science.gov (United States)

    Liang, Xiaoliang; Liu, Peng; He, Hongping; Wei, Gaoling; Chen, Tianhu; Tan, Wei; Tan, Fuding; Zhu, Jianxi; Zhu, Runliang

    2016-04-01

    In this study, a series of Mn substituted spinel ferrites calcinated at different temperatures were used as catalysts for the oxidation of formaldehyde (HCHO). X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and H2 temperature-programmed reduction were conducted to characterize the structure and physico-chemical properties of catalysts, which were affected by calcination in the range of 200-600°C. Results show that all the ferrites were with spinel structure, and those calcinated in the range of 300-600°C were in the phase of maghemite. The calcination changed the valence and distribution of Mn and Fe on the ferrite surface, and accordingly the reducibility of ferrites. The HCHO catalytic oxidation test showed that with the increase of calcination temperature, the activity was initially improved until 400°C, but then decreased. The variation of HCHO conversion performance was well positively correlated to the variation of reduction temperature of surface Mn(4+) species. The remarkable effect of calcination on the catalytic activity of Mn-doped spinel ferrites for HCHO oxidation was discussed in view of reaction mechanism and variations in cationic microstructure of Mn-doped ferrites. PMID:26774985

  20. Physical, Chemical and Structural Evolution of Zeolite - Containing Waste Forms Produced from Metakaolinite and Calcined HLW

    Energy Technology Data Exchange (ETDEWEB)

    Grutzeck, Michael

    2005-06-01

    During the seventh year of the current grant (DE-FG02-05ER63966) we completed an exhaustive study of cold calcination and began work on the development of tank fill materials to fill empty tanks and control residuals. Cold calcination of low and high NOx low activity waste (LAW) SRS Tank 44 and Hanford AN-107 simulants, respectively with metallic Al + Si powders was evaluated. It was found that a combination of Al and Si powders could be used as reducing agents to reduce the nitrate and nitrite content of both low and high NOx LAW to low enough levels to allow the LAW to be solidified directly by mixing it with metakaolin and allowing it to cure at 90 C. During room temperature reactions, NOx was reduced and nitrogen was emitted as N2 or NH3. This was an important finding because now one can pretreat LAW at ambient temperatures which provides a low-temperature alternative to thermal calcination. The significant advantage of using Al and Si metals for denitration/denitrition of the LAW is the fact that the supernate could potentially be treated in situ in the waste tanks themselves. Tank fill materials based upon a hydroceramic binder have been formulated from mixtures of metakaolinite, Class F fly ash and Class C flue gas desulphurization (FGD) ash mixed with various concentrations of NaOH solution. These harden over a period of hours or days depending on composition. A systematic study of properties of the tank fill materials (leachability) and ability to adsorb and hold residuals is under way.

  1. Physical, Chemical and Structural Evolution of Zeolite - Containing Waste Forms Produced from Metakaolinite and Calcined HLW

    International Nuclear Information System (INIS)

    During the seventh year of the current grant (DE-FG02-05ER63966) we completed an exhaustive study of cold calcination and began work on the development of tank fill materials to fill empty tanks and control residuals. Cold calcination of low and high NOx low activity waste (LAW) SRS Tank 44 and Hanford AN-107 simulants, respectively with metallic Al + Si powders was evaluated. It was found that a combination of Al and Si powders could be used as reducing agents to reduce the nitrate and nitrite content of both low and high NOx LAW to low enough levels to allow the LAW to be solidified directly by mixing it with metakaolin and allowing it to cure at 90 C. During room temperature reactions, NOx was reduced and nitrogen was emitted as N2 or NH3. This was an important finding because now one can pretreat LAW at ambient temperatures which provides a low-temperature alternative to thermal calcination. The significant advantage of using Al and Si metals for denitration/denitrition of the LAW is the fact that the supernate could potentially be treated in situ in the waste tanks themselves. Tank fill materials based upon a hydroceramic binder have been formulated from mixtures of metakaolinite, Class F fly ash and Class C flue gas desulphurization (FGD) ash mixed with various concentrations of NaOH solution. These harden over a period of hours or days depending on composition. A systematic study of properties of the tank fill materials (leachability) and ability to adsorb and hold residuals is under way

  2. PREPARATION AND PROPERTIES OF Co-Fe MIXED OXIDES OBTAINED BY CALCINATION OF LAYERED DOUBLE HYDROXIDES

    Directory of Open Access Journals (Sweden)

    M. E. Pérez Bernal

    2004-12-01

    Full Text Available Solids containing Co(II and Fe(III with molar ratios of 2/1, 3/2, 1/1, 2/3 and 1/2 have been synthetised by coprecipitation at constant pH. All they displayed a hydrotalcite-like structure with interlayer carbonate, which crystallinity decreases as the iron content was increased. No other crystalline phase was identified, even in the Fe-rich samples. They have been characterised by powder X-ray diffraction, FT-IR spectroscopy, thermal analysis (differential thermal analysis, thermogravimetric analysis and temperature-programmed reduction, in addition to specific surface area assessment by nitrogen adsorption at -196°C. A minor oxidation of Co(II to Co(III is observed in the Co-rich samples, although it reverses again to Co(II upon calcination in oxygen at ca. 850°C. Thermal decomposition takes place in a single step up to ca. 350°C, and the specific surface area increases with the iron content, probably because of the presence of hydrated amorphous iron oxides. The solids calcined at 1200°C in air contain crystalline CoO, Co3O4 and CoFe2O4 (spinel, this one being the dominant phase, and only phase detected for large Fe contents. Metallic species are more easily reduced in the original solids than in the calcined ones, and in all cases iron seems to be reduced at a higher temperature than cobalt.

  3. Investigation of corrosion experienced in a spray calciner/ceramic melter vitrification system

    International Nuclear Information System (INIS)

    After periodic testing of a large-scale spray calciner/ceramic melter vitrification system over a 2-yr period, sufficient corrosion was noted on various parts of the vitrification system to warrant its disassembly and inspection. A majority of the 316 SS sintered metal filters on the spray calciner were damaged by chemical corrosion and/or high temperature oxidation. Inconel-601 portions of the melter lid were attacked by chlorides and sulfates which volatilized from the molten glass. The refractory blocks, making up the walls of the melter, were attacked by the waste glass. This attack was occurring when operating temperatures were >12000C. The melter floor was protected by a sludge layer and showed no corrosion. Corrosion to the Inconel-690 electrodes was minimal, and no corrosion was noted in the offgas treatment system downstream of the sintered metal filters. It is believed that most of the melter corrosion occurred during one specific operating period when the melter was operated at high temperatures in an attempt to overcome glass foaming behavior. These high temperatures resulted in a significant release of volatile elements from the molten glass, and also created a situation where the glass was very fluid and convective, which increased the corrosion rate of the refractories. Specific corrosion to the calciner components cannot be proven to have occurred during a specific time period, but the mechanisms of attack were all accelerated under the high-temperature conditions that were experienced with the melter. A review of the materials of construction has been made, and it is concluded that with controlled operating conditions and better protection of some materials of construction corrosion of these systems will not cause problems. Other melter systems operating under similar strenuous conditions have shown a service life of 3 yr

  4. Structure and Pozzolanic Activity of Calcined Coal Gangue during the Process of Mechanical Activation

    Institute of Scientific and Technical Information of China (English)

    GUO Wei; LI Dongxu; CHEN Jianhua; YANG Nanru

    2009-01-01

    On the basis of analyzing coal gangue's chemical and mineral compositions, the structure change of coal gangue during the mechanical activation was investigated by XRD, FTIR,NMR, and the mechanical strength of the cement doped coal gangue with various specific surface area was tested. The experimental results indicate that, the lattice structure of metakaolin in coal gangue samples calcined at 700 ℃ disorganizes gradually and becomes disordered, and the lattice structure of α-quartz is distorted slightly. The pozzolanic activity of the coal gangue increases obviously with its structural disorganization.

  5. Vitrification of radioactive high-level waste by spray calcination and in-can melting

    International Nuclear Information System (INIS)

    After several nonradioactive test runs, radioactive waste from the processing of 1.5 t of spent, light-water-reactor fuel was successfully concentrated, dried and converted to a vitreous product. A total of 97 L of waste glass (in two stainless steel canisters) was produced. The spray calcination process coupled to the in-can melting process, as developed at Pacific Northwest Laboratory, was used to vitrify the waste. An effluent system consisting of a variety of condensation of scrubbing steps more than adequately decontaminated the process off gas before it was released to the atmosphere

  6. Effect of the rate of calcination of kaolin on the properties of metakaolin-based geopolymers

    OpenAIRE

    B.B. Kenne Diffo; A. Elimbi; Cyr, M; J. Dika Manga; H. Tchakoute Kouamo

    2015-01-01

    Kaolin samples of the same mass were treated at 700 °C for the same duration of 30 min by varying the rate of calcination (1, 2.5, 5, 10, 15 and 20 °C/min) in order to obtain metakaolins which were used to produce geopolymers. Depending on the nature of each type of material, kaolin, metakaolins and geopolymers were characterized using thermal analysis, chemical analysis, XRD, FTIR, particle size distribution, specific surface area, bulk density, setting time and compressive strength. FTIR an...

  7. Idaho National Engineering and Environmental Laboratory, Old Waste Calcining Facility, Scoville vicinity, Butte County, Idaho -- Photographs, written historical and descriptive data. Historical American engineering record

    International Nuclear Information System (INIS)

    This report describes the history of the Old Waste Calcining Facility. It begins with introductory material on the Idaho National Engineering and Environmental Laboratory, the Materials Testing Reactor fuel cycle, and the Idaho Chemical Processing Plant. The report then describes management of the wastes from the processing plant in the following chapters: Converting liquid to solid wastes; Fluidized bed waste calcining process and the Waste Calcining Facility; Waste calcining campaigns; WCF gets a new source of heat; New Waste Calcining Facility; Last campaign; Deactivation and the RCRA cap; Significance/context of the old WCF. Appendices contain a photo key map for HAER photos, a vicinity map and neighborhood of the WCF, detailed description of the calcining process, and chronology of WCF campaigns

  8. Optimization of hydrogen dynamic heat treatment and re-calcination for preparation of strontium hexaferrite nanocrystalline powder

    International Nuclear Information System (INIS)

    Strontium hexaferrite is a hard magnetic material which under hydrogen treatment and re-calcination, its phase composition and also particles size and morphology change completely. Strontium hexaferrite was prepared by conventional route with calcination of strontium carbonate and hematite at 1100 deg. C for 1 h. Then strontium hexaferrite was heat treated in hydrogen dynamic atmosphere at various temperatures and gas flows for different times. Optimum conditions of hydrogen treatment were obtained at 850 deg. C with 60 cm3/min flow for 1 h. Subsequent re-calcination was carried out at various temperatures for the optimum hydrogen treated powder and its optimum conditions were obtained at 1000 deg. C for 1 h. The effect of dynamic hydrogen treatment and re-calcination on the phase composition and particles size and morphology characterized by X-ray diffraction (XRD) and scanning and transmission electron microscopes (SEM and TEM). The results showed decomposition of strontium hexaferrite and reduction of the resultant hematite mainly to iron during hydrogen treatment. Nanocrystalline powder of strontium hexaferrite was also reformed after the re-calcination. The magnetic properties of the initial and final strontium hexaferrite powder were measured by a vibration sample magnetometer (VSM). The results showed about 30% increase in the coercivity by application of this process on the strontium hexaferrite powder.

  9. Relevant influence of limestone crystallinity on CO₂ capture in the Ca-looping technology at realistic calcination conditions.

    Science.gov (United States)

    Valverde, J M; Sanchez-Jimenez, P E; Perez-Maqueda, L A

    2014-08-19

    We analyze the role of limestone crystallinity on its CO2 capture performance when subjected to carbonation/calcination cycles at conditions mimicking the Ca-looping (CaL) technology for postcombustion CO2 capture. The behavior of raw and pretreated limestones (milled and thermally annealed) is investigated by means of thermogravimetric analysis (TGA) tests under realistic sorbent regeneration conditions, which necessarily involve high CO2 partial pressure in the calciner and quick heating rates. The pretreatments applied lead to contrasting effects on the solid crystal structure and, therefore, on its resistance to solid-state diffusion. Our results show that decarbonation at high CO2 partial pressure is notably promoted by decreasing solid crystallinity. CaO regeneration is fully achieved under high CO2 partial pressure at 900 °C in short residence times for the milled limestone whereas complete regeneration for raw limestone requires a minimum calcination temperature of about 950 °C. Such a reduction of the calcination temperature and the consequent mitigation of multicyclic capture capacity decay would serve to enhance the efficiency of the CaL technology. On the other hand, the results of our study suggest that the use of highly crystalline limestones would be detrimental since excessively high calcination temperatures should be required to attain full decarbonation at realistic conditions.

  10. The effects of calcination temperature on the electrochemical performance of LiMnPO4 prepared by ultrasonic spray pyrolysis

    International Nuclear Information System (INIS)

    Research highlights: → Carbon-coated LiMnPO4 cathode materials were prepared by ultrasonic spray pyrolysis. → The effects of calcinations temperature on the microstructure and electrochemical performance of C-LiMnPO4 were investigated. → X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations revealed that the calcination temperature had a strong influence on the morphology and crystallite size of the prepared final powder, and therefore the subsequent electrochemical performance of the material. → The C-LiMnPO4 powders prepared at 650 oC exhibited excellent electrochemical performance with a discharge capacity of 118 mAh g-1. - Abstract: Carbon-coated LiMnPO4 powders were prepared by ultrasonic spray pyrolysis. The effects of calcination temperature on the microstructure and electrochemical performance of C-LiMnPO4 were investigated. X-ray diffraction (XRD) studies showed that the crystallite size varied with calcination temperature. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations revealed that the calcination temperature had a strong influence on the morphology of the prepared final powder, and therefore the subsequent electrochemical performance of the material. The C-LiMnPO4 powders prepared at 650 oC exhibited excellent electrochemical performance with a discharge capacity of 118 mAh g-1.

  11. Preparation of Nanosized LaCoO3 through Calcination of a Hydrothermally Synthesized Precursor

    Directory of Open Access Journals (Sweden)

    L. Tepech-Carrillo

    2016-01-01

    Full Text Available A method for obtaining nanosized LaCoO3 crystals from calcination of a precursor powder synthesized by a hydrothermal route is reported. Details concerning the evolution of the microstructure and formation mechanism of the perovskite phase were studied by powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, Raman spectroscopy, and thermal analysis. It was found that the morphology of the sample progressively turns from a mix of fibers and rods to interconnected nanocrystals. It is determined that LaCoO3 phase is produced by a reaction of cobalt and lanthanum oxides, the latter produced by a two-step dehydration process of La(OH3. Finally, it was found that nearly stoichiometric LaCoO3 nanocrystals can be obtained at temperatures as low as 850°C. Nevertheless, whether higher calcination temperatures are used, appropriate reaction times and a controlled atmosphere are required in order to avoid formation of lanthanum carbonates and high density of lattice defects.

  12. Effects of Composition and Calcination Temperature on Photocatalytic Evolution over from Glycerol and Water Mixture

    Directory of Open Access Journals (Sweden)

    Cancan Fan

    2012-01-01

    Full Text Available A series of sulfide coupled semiconductors supported on SiO2, (, was prepared by incipient wet impregnation method. The photocatalysts were characterized by XRD, XPS, TPR, and UV/Vis DRS. Characterization results show that the chemical actions between ZnS and CdS resulted in the formation of solid solutions on the surface of the support and the formation of them is affected by the molar ratio of ZnS/CdS and calcination temperature. Performance of photocatalysts was tested in the home made reactor under both UV light and solar-simulated light irradiation by detecting the rate of the photocatalytic H2 evolution from glycerol solution. The hydrogen production rates are related to the catalyst composition, surface structure, photoabsorption property, as well as the amount of solid solution. The maximum rate of hydrogen production, 550 μmol·h−1 under UV light irradiation and 210 μmol·h−1 under solar-simulated light irradiation, was obtained over Cd0.8Zn0.2S/SiO2 solid solution calcined at 723 K.

  13. Removal of acid blue 062 on aqueous solution using calcinated colemanite ore waste

    International Nuclear Information System (INIS)

    Colemanite ore waste (CW) has been employed as adsorbent for the removal of acid blue 062 anionic dye (AB 062) from aqueous solution. The adsorption of AB 062 onto CW was examined with respect to contact time, calcination temperature, particle size, pH, adsorbent dosage and temperature. The physical and chemical properties of the CW, such as particle sizes and calcinations temperature, play important roles in dye adsorption. The dye adsorption largely depends on the initial pH of the solution with maximum uptake occurring at pH 1.Three simplified kinetics models, namely, pseudo-first order, pseudo-second order, and intraparticle diffusion models were tested to investigate the adsorption mechanisms. The kinetic adsorption of AB 062 on CW follows a pseudo-second order equation. The adsorption data have been analyzed using Langmuir and Freundlich isotherms. The results indicate that the Langmuir model provides the best correlation of the experimental data. Isotherms have also been used to obtain the thermodynamic parameters such as free energy, enthalpy and entropy of the adsorption of dye onto CW

  14. Mercury removal at Idaho National Engineering and Environmental Laboratory's New Waste Calciner Facility

    International Nuclear Information System (INIS)

    Technologies were investigated to determine viable processes for removing mercury from the calciner (NWCF) offgas system at the Idaho National Engineering and Environmental Laboratory. Technologies for gas phase and aqueous phase treatment were evaluated. The technologies determined are intended to meet EPA Maximum Achievable Control Technology (MACT) requirements under the Clean Air Act and Resource Conservation and Recovery Act (RCRA). Currently, mercury accumulation in the calciner off-gas scrubbing system is transferred to the tank farm. These transfers lead to accumulation in the liquid heels of the tanks. The principal objective for aqueous phase mercury removal is heel mercury reduction. The system presents a challenge to traditional methods because of the presence of nitrogen oxides in the gas phase and high nitric acid in the aqueous scrubbing solution. Many old and new technologies were evaluated including sorbents and absorption in the gas phase and ion exchange, membranes/sorption, galvanic methods, and UV reduction in the aqueous phase. Process modifications and feed pre-treatment were also evaluated. Various properties of mercury and its compounds were summarized and speciation was predicted based on thermodynamics. Three systems (process modification, NOxidizer combustor, and electrochemical aqueous phase treatment) and additional technology testing were recommended

  15. Pecularities of carrying out radioactive wastes vitrification process without preliminary calcination of wastes

    International Nuclear Information System (INIS)

    Vitrification technology is considered for liquid radioactive wastes by means of electric furnace where heating of glass-paste is done by electric current passing through the melt. Continious process of gehydration, calcination and vitrification is going on in one apparatus. Testing if the method has been performed by use of a model solution, containing sodium and aluminium nitrates. To obtain phosphoric acid has been added into the solution. Lay-out of the device and its description as well as technical parameters of the electric furnace are given. The results are stated for determination of the optimum operation conditions for the device. To reduce entrainment of solid components, molasses has been added in the solution. Parameters are given for the process of the solution containing 80 g/l molasses processing. It has been shown that edding molasses to the solution permitted to reduse power consumption of the process due to the heat generation during oxidation-reduction reaction on the melt surface. The results are given for investigations of the nitrogen oxides catching in scrubbers. These results have shown that introduction of molasses reduces nitrigen oxides concentration. The results of the experimental works have shown the possibility of the continious process of dehydration, calcination and vitrification in single device with application of remote control and monitoring by means of automatics. (I.T.)

  16. Implementation of industrial waste ferrochrome slag in conventional and low cement castables: Effect of calcined alumina

    Directory of Open Access Journals (Sweden)

    Pattem Hemanth Kumar

    2014-12-01

    Full Text Available A new class of conventional and low-cement ferrochrome slag-based castables were prepared from 40 wt.% ferrochrome slag and 45 wt.% calcined bauxite. Rest fraction varied between high alumina cement (HAC acting as hydraulic binder and calcined alumina as pore filling additive. Standard ASTM size briquettes were prepared for crushing and bending strengths evaluation, and the samples were then subjected to firing at 800, 1100 and 1300 °C for a soaking period of 3 h. The microstructure and refractory properties of the prepared castables have been investigated using X-ray diffraction (XRD, scanning electron microscopy (SEM, cold crushing strength, modulus of rupture and permanent linear changes (PLCs test. Castables show good volume stability (linear change <0.7% at 1300 °C. The outcomes of these investigations were efficacious and in accordance with previously reported data of similar compositions. High thermo-mechanical and physico-chemical properties were attained pointing out an outstanding potential to increase the refractory lining working life of non-recovery coke oven and reheating furnaces.

  17. Calcination temperature influenced multiferroic properties of Ca-doped BiFeO3 nanoparticles

    Science.gov (United States)

    Dhir, Gitanjali; Uniyal, Poonam; Verma, N. K.

    2015-06-01

    The influence of Ca-doping and particle size on structural, morphological and magnetic properties of BiFeO3 nanoparticles has been studied. A sol-gel method was employed for the synthesis of nanoparticles and their particle size was tailored by varying the calcination temperature. Structural analysis revealed a rhombohedral distortion induced by Ca-substitution. The broadening of diffraction peaks with decreasing calcination temperature was indicative of reduction in crystallite size. The morphological analysis revealed the formation of agglomerated nanoparticles having average particle size ranging from 10-15 and 50-55 nm for C4 and C6, respectively. The agglomeration is attributed to high surface energy of nanoparticles. Ferromagnetism has been displayed by all the synthesized nanoparticles. Enhancement of saturation magnetization with Ca-substitution is attributed to suppression of spin cycloid structure by the reduction in size, lattice distortion and creation of oxygen vacancies by the substitution of divalent ion at trivalent site. Further, this value increases as a function of decreasing particle size. Strong particle size effects on magnetic properties of the synthesized nanoparticles are owed to increasing surface to volume ratio. All these observations are indicative of strong dependence of multiferroism on particle size.

  18. Calcination temperature influenced multiferroic properties of Ca-doped BiFeO{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Dhir, Gitanjali, E-mail: gitanjali.thaprian@gmail.com; Uniyal, Poonam; Verma, N. K. [Nano Research Lab, School of Physics and Materials Science, Thapar University, Patiala-147004 (India)

    2015-06-24

    The influence of Ca-doping and particle size on structural, morphological and magnetic properties of BiFeO{sub 3} nanoparticles has been studied. A sol-gel method was employed for the synthesis of nanoparticles and their particle size was tailored by varying the calcination temperature. Structural analysis revealed a rhombohedral distortion induced by Ca-substitution. The broadening of diffraction peaks with decreasing calcination temperature was indicative of reduction in crystallite size. The morphological analysis revealed the formation of agglomerated nanoparticles having average particle size ranging from 10-15 and 50-55 nm for C4 and C6, respectively. The agglomeration is attributed to high surface energy of nanoparticles. Ferromagnetism has been displayed by all the synthesized nanoparticles. Enhancement of saturation magnetization with Ca-substitution is attributed to suppression of spin cycloid structure by the reduction in size, lattice distortion and creation of oxygen vacancies by the substitution of divalent ion at trivalent site. Further, this value increases as a function of decreasing particle size. Strong particle size effects on magnetic properties of the synthesized nanoparticles are owed to increasing surface to volume ratio. All these observations are indicative of strong dependence of multiferroism on particle size.

  19. Grain Growth Kinetics of BaTiO3 Nanocrystals During Calcining Process

    Science.gov (United States)

    Song, Xiao-lan; He, Xi; Yang, Hai-ping; Qu, Yi-xin; Qiu, Guan-zhou

    2008-06-01

    BaTiO3 nanocrystals were synthesized by sol-gel method using barium acetate (Ba(CH3COO)2) and tetra-butyl titanate (Ti(OC4H9)4) as raw materials. Xerogel precursors and products were characterized by means of thermogravimetric/differential scanning calorimetry (TG/DSC), X-ray diffraction (XRD) and transmission electron microscope (TEM). The influence of the calcination temperature and duration on the lattice constant, the lattice distortion, and the grain size of BaTiO3 nanocrystals was discussed based on the XRD results. The grain growth kinetics of BaTiO3 nanocrystals during the calcination process were simulated with a conventional grain growth model which only takes into account diffusion, and an isothermal model proposed by Qu and Song, which takes into account both diffusion and surface reactions. Using these models, the pre-exponential factor and the activation energy of the rate constant were estimated. The simulation results indicate that the isothermal model is superior to the conventional one in describing the grain growth process, implying that both diffusion and surface reactions play important roles in the grain growth process.

  20. Calcined Mg-Fe layered double hydroxide as an absorber for the removal of methyl orange

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Chao [School of Civil Engineering and Mechanics, Central South University of Forestry and Technology, Changsha 410004, Hunan (China); State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070 (China); Dai, Jing [Key Laboratory of Advanced Technology for Special Functional Materials of Ministry of Education, Wuhan 430070 (China); Yu, Jianying, E-mail: Yujianyingwhut@163.com [State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070 (China); Yin, Jian [School of Civil Engineering and Mechanics, Central South University of Forestry and Technology, Changsha 410004, Hunan (China)

    2015-05-15

    In this work, methyl orange (MO) was effectively removed from aqueous solution with the calcined product of hydrothermal synthesized Mg/Fe layered double hydroxide (Mg/Fe-LDH). The structure, composition, morphology and textural properties of the Mg/Fe-LDH before and after adsorption were characterized by X-ray diffraction, Fourier transformation infrared spectroscopy, transmission electron microscopy, nitrogen adsorption apparatus and X-ray photoelectron spectroscopy. It was confirmed that MO had been absorbed by calcined Mg/Fe-LDH which had strong interactions with MO. The adsorption of MO onto the Mg/Fe-LDH was systematically investigated by batch tests. The adsorption capacity of the Mg/Fe-LDH toward MO was found to be 194.9 mg • g{sup −1}. Adsorption kinetics and isotherm studies revealed that the adsorption of MO onto Mg/Fe-LDH was a spontaneous and endothermic process. These results indicate that Mg/Fe-LDH is a promising material for the removal of MO.

  1. Manganese oxide phases and morphologies: A study on calcination temperature and atmospheric dependence

    Directory of Open Access Journals (Sweden)

    Matthias Augustin

    2015-01-01

    Full Text Available Manganese oxides are one of the most important groups of materials in energy storage science. In order to fully leverage their application potential, precise control of their properties such as particle size, surface area and Mnx+ oxidation state is required. Here, Mn3O4 and Mn5O8 nanoparticles as well as mesoporous α-Mn2O3 particles were synthesized by calcination of Mn(II glycolate nanoparticles obtained through an economical route based on a polyol synthesis. The preparation of the different manganese oxides via one route facilitates assigning actual structure–property relationships. The oxidation process related to the different MnOx species was observed by in situ X-ray diffraction (XRD measurements showing time- and temperature-dependent phase transformations occurring during oxidation of the Mn(II glycolate precursor to α-Mn2O3 via Mn3O4 and Mn5O8 in O2 atmosphere. Detailed structural and morphological investigations using transmission electron microscopy (TEM and powder XRD revealed the dependence of the lattice constants and particle sizes of the MnOx species on the calcination temperature and the presence of an oxidizing or neutral atmosphere. Furthermore, to demonstrate the application potential of the synthesized MnOx species, we studied their catalytic activity for the oxygen reduction reaction in aprotic media. Linear sweep voltammetry revealed the best performance for the mesoporous α-Mn2O3 species.

  2. Study on Effects of Calcine Conditions on Physic-chemical Character of Calcined Kaolinite%煅烧条件对煤系煅烧高岭土物化性能影响的研究

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The effects of material fines,calcinating temperature,raising temperature's velocity,addition agent as well as hydrogenant condition on physic-chemical character of calcined kaolinite are investigated.%研究了煤系高岭土在煅烧过程中原料细度、煅烧温度、恒温时间、升温速度、添加剂及还原气氛对产品物化性能的影响。

  3. Effects of precoating and calcination on microstructure of 3D silica fiber reinforced silicon nitride based composites

    Institute of Scientific and Technical Information of China (English)

    QI Gong-jin; ZHANG Chang-rui; HU Hai-feng

    2006-01-01

    Three-dimensional silica fiber reinforced silicon nitride based composites were fabricated by preceramic polymer infiltration and pyrolysis method using perhydropolysilazane as a precursor. The effects of precoating and high temperature calcination on the microstructures of the composites were investigated by scanning electron microscopy. For the composite without a precoating, the fracture surface is plain, and the fiber/matrix interfaces become very unclear after calcination at 1 600 ℃ due to intense interfacial reactions. The composite with a precoating shows tough fracture surface with distinct fiber pull-outs, and the fiber/matrix interfaces are still clear after calcination at 1 600 ℃. It is the appropriate precoating process that contributes to the good interfacial microstructures for the composite.

  4. High-Temperature Release of SO2 from Calcined Cement Raw Materials

    DEFF Research Database (Denmark)

    Nielsen, Anders Rooma; Larsen, Morten B.; Glarborg, Peter;

    2011-01-01

    and experiments in a tube furnace reactor in the temperature interval of 900–1100 °C. The investigated conditions resemble actual conditions in the material inlet end of cement rotary kilns. It was found that the sulfates CaSO4, K2SO4, and Na2SO4 were all stable under oxidizing conditions but began to decompose...... concentration, which may cause deposit formation in the kiln system. In this study, the release of sulfur from calcined cement raw materials under both oxidizing and reducing conditions is investigated. The investigations include thermodynamic equilibrium calculations in the temperature interval of 800–1500 °C...... under reducing conditions. Particularly, CaSO4 was sensitive to reducing conditions. The sulfur release was most significant if the gas atmosphere frequently shifted between oxidizing and reducing conditions. An increasing temperature from 900 to 1100 °C under alternating oxidizing and reducing...

  5. Enhancement of biohydrogen production from brewers' spent grain by calcined-red mud pretreatment.

    Science.gov (United States)

    Zhang, Jishi; Zang, Lihua

    2016-06-01

    This paper investigated the utilization of calcined-red mud (CRM) pretreatment to enhance fermentative hydrogen yields from brewers' spent grain (BSG). The BSG samples were treated with different concentrations (0.0-20g/L) of CRM at 55°C for 48h, before the biohydrogen process with heat-treated anaerobic sludge inoculum. The highest specific hydrogen production of 198.62ml/g-VS was obtained from the BSG treated with 10g/L CRM, with the corresponding lag time of 10.60h. Hydrogen yield increments increased by 67.74%, compared to the control tests without CRM. The results demonstrated that the CRM could hydrolyze more cellulose and further provided adequate broth and suitable pH value for efficient fermentative hydrogen. The model-based analysis showed that the modified Gompertz model presented a better fit for the experimental data than the first-order model. PMID:26950758

  6. Effect of calcination temperature on phase transformation of HfO2 nanoparticles

    International Nuclear Information System (INIS)

    Oxides nanomaterials exhibit unique physical, chemical and structural properties and motivated a big research that focus in the integration of these materials for various optoelectronic device applications. In present work, hafnium oxide (HfO2) nanoparticles (NPs) have been synthesized using precipitation method. Hafnium tetrachloride and sodium hydroxide has been used as starting precursors. Prepared oxide material has been characterized by X-Ray Diffraction (XRD), Fourier Transform Infra-Red (FTIR) and UV-Vis spectroscopy. The phase transformation from amorphous to monoclinic is observed with the increase in calcination temperature from 500 °C and 800 °C. In FTIR spectra, the characteristic bands at ν ∼ 758.53 and 509.57 cm−1 reveals the monoclinic phase of prepared HfO2 NPs. UV-Vis spectroscopy shows an absorption peak at 204 nm and the bandgap calculated is 6.07 eV

  7. Application of coal-water slurry on the rotary calcining kiln of pedgion magnesium reduction process

    Institute of Scientific and Technical Information of China (English)

    LI Hua-qing; XIE Shui-sheng; LIU Jin-ping; WU Peng-yue; HUANG Guo-jie

    2006-01-01

    Energy saving has been an important concept in modern industry especially to the countries and regions with energy shortage such as China and Japan. Utilization of Coal-Water Slurry (CWS) can improve the burning efficiency of coal and reduce the pollutions of soot, sulfide and the nitride by burning lump coal directly. The CWS is a promising energy saving technique and the effectual substitute of oil. The study on the preparation and application of the CWS has made progresses in many aspects. The present paper studied the basal problems for applying the CWS on the rotary kilns during the calcining-dolomite process in the magnesium factory, summarized the key points for the application process of the CWS and gave the corresponding solutions.

  8. Effect of calcination temperature on phase transformation of HfO{sub 2} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Tripathi, S. K., E-mail: surya@pu.ac.in [Department of Physics, Center of Advanced Study in Physics, Panjab University, Chandigarh-160 014 (India); Center of Nanoscience and Nanotechnology, Panjab University, Chandigarh-160 014 (India); Kaur, Charanpreet [Center of Nanoscience and Nanotechnology, Panjab University, Chandigarh-160 014 (India); Kaur, Ramneek; Kaur, Jagdish [Department of Physics, Center of Advanced Study in Physics, Panjab University, Chandigarh-160 014 (India)

    2015-08-28

    Oxides nanomaterials exhibit unique physical, chemical and structural properties and motivated a big research that focus in the integration of these materials for various optoelectronic device applications. In present work, hafnium oxide (HfO{sub 2}) nanoparticles (NPs) have been synthesized using precipitation method. Hafnium tetrachloride and sodium hydroxide has been used as starting precursors. Prepared oxide material has been characterized by X-Ray Diffraction (XRD), Fourier Transform Infra-Red (FTIR) and UV-Vis spectroscopy. The phase transformation from amorphous to monoclinic is observed with the increase in calcination temperature from 500 °C and 800 °C. In FTIR spectra, the characteristic bands at ν ∼ 758.53 and 509.57 cm{sup −1} reveals the monoclinic phase of prepared HfO{sub 2} NPs. UV-Vis spectroscopy shows an absorption peak at 204 nm and the bandgap calculated is 6.07 eV.

  9. Twofold role of calcined hydrotalcites in the degradation of methyl parathion pesticide

    Directory of Open Access Journals (Sweden)

    Alvaro Sampieri

    2011-02-01

    Full Text Available Methyl parathion (MP is a very toxic organophosphate pesticide used as a non-systematic insecticide and acaricide on many corps. As MP and its by-products are highly toxic, they have to be retained to avoid pollution of rivers and lakes. Highly efficient sorbents are hydrotalcites (HTs (or anionic clays. We have correlated the degradation of an aqueous solution of MP at room temperature, with the basicity of the adsorbing materials. It was found that the metal composition of hydrotalcites determines both the surface electronic properties (basic or acidic and the sorption capacity. Depending on the basic strength, some calcined hydrotalcites can catalyze the transformation of MP to p-nitrophenol (p-NP and retain its by-products. Such a process has the advantage of being able to be carried out at room temperature and at the pH of the pesticide solution.

  10. Twofold role of calcined hydrotalcites in the degradation of methyl parathion pesticide.

    Science.gov (United States)

    Sampieri, Alvaro; Fetter, Geolar; Villafuerte-Castrejon, María Elena; Tejeda-Cruz, Adriana; Bosch, Pedro

    2011-01-01

    Methyl parathion (MP) is a very toxic organophosphate pesticide used as a non-systematic insecticide and acaricide on many corps. As MP and its by-products are highly toxic, they have to be retained to avoid pollution of rivers and lakes. Highly efficient sorbents are hydrotalcites (HTs) (or anionic clays). We have correlated the degradation of an aqueous solution of MP at room temperature, with the basicity of the adsorbing materials. It was found that the metal composition of hydrotalcites determines both the surface electronic properties (basic or acidic) and the sorption capacity. Depending on the basic strength, some calcined hydrotalcites can catalyze the transformation of MP to p-nitrophenol (p-NP) and retain its by-products. Such a process has the advantage of being able to be carried out at room temperature and at the pH of the pesticide solution.

  11. Study of Surface Modification Mechanism of Calcined Kaolin by MAS NMR

    Institute of Scientific and Technical Information of China (English)

    杨晓杰; 邓飞皇; 张蓓

    2002-01-01

    The 29Si and 27Al in modified and unmodified calcined kaolin were res earched and compared by using MAS NMR. The result shows that the chemical shift of -106×10-6 of 29Si almost keeps unchanged after being modifie d, but 27Al cha nges obviously. The chemical shift of 5.44×10-6 and 65.69×10-6 of 27Al are sep arately shifted to 3.8×10-6-4.4×10-6 and 54.6×10-6-59.9×1 0-6 after being mod ified. And the chemical modification of kaolin is completed by linking with Al o n the surface of it.

  12. Physical Properties of Calcined Kaolin (Kibi,Ghana) Aggregate Refractory Bodies

    Institute of Scientific and Technical Information of China (English)

    K.Amoako-Appiagyei

    1998-01-01

    Properties of refractories affect their perfor-mance and deformation behaviour as well as their ultimate failure mode,Therefore in ordr to assess the capabilities of materials,used for refractory lin-ings,in service their properties must be evaluated.In this work the evaluation of some physical properties of calcined kaloin(Kibi,Ghana)aggregate re-fractory bodies showed an average porosity and spe-cific gravity of 24% and 2.78 respectively,An av-erage cold crushing strength of 19.6 MPa was also obtained .Thermal expansion and behaviour under a constant hot load of 196 kPa also showed good resis-tance to high temperature deformation.

  13. Enhancement of biohydrogen production from brewers' spent grain by calcined-red mud pretreatment.

    Science.gov (United States)

    Zhang, Jishi; Zang, Lihua

    2016-06-01

    This paper investigated the utilization of calcined-red mud (CRM) pretreatment to enhance fermentative hydrogen yields from brewers' spent grain (BSG). The BSG samples were treated with different concentrations (0.0-20g/L) of CRM at 55°C for 48h, before the biohydrogen process with heat-treated anaerobic sludge inoculum. The highest specific hydrogen production of 198.62ml/g-VS was obtained from the BSG treated with 10g/L CRM, with the corresponding lag time of 10.60h. Hydrogen yield increments increased by 67.74%, compared to the control tests without CRM. The results demonstrated that the CRM could hydrolyze more cellulose and further provided adequate broth and suitable pH value for efficient fermentative hydrogen. The model-based analysis showed that the modified Gompertz model presented a better fit for the experimental data than the first-order model.

  14. Mechanisms and kinetics of high-temperature cadmium sorption by packed bed of calcined kaolin.

    Science.gov (United States)

    Yang, H C; Yun, J S; Kang, M J; Kang, Y; Kim, J H

    2001-01-01

    Sorption experiments by passing CdCl2-carrying flue gas through the packed bed of calcined macro-porous kaolin particles were performed over a temperature range of 973-1173K and a CdCl2 partial pressure range of 8-16.1 Pa. The observed structural change of the sorbent mineral at the stage of sorption and the results of desorption tests revealed the characteristics of an irreversible chemical reaction as a major cadmium capturing mechanism. In the fully saturated kaolin sorbent, CdO x Al2O x 2SiO2 is present as a sorption reaction product together with a smaller amount of 2CdO x Al2O x 2SiO2. The increase in sorbent bed temperature resulted in an increase in the rate of sorption, but it had no effect on maximum cadmium uptake. The gas-phase CdCl2 diffusion into the macro pores of calcined kaolin had a negligible effect on the overall sorption rate. The reaction between gaseous CdCl2 and solid Al2O3 x 2SiO2 is very sensitive to the concentration of CdCl2 but relatively insensitive to the temperature of the sorbent bed. The order of reaction with respect to the CdCl2 vapor concentration was determined to be 3.26. The activation energy, Ea, was estimated as 5.56 kcal/mol according to the Arrhenius relationship. PMID:11688684

  15. Proposed Atomic Energy of Canada Ltd. 99Mo waste calcination process

    International Nuclear Information System (INIS)

    Atomic Energy of Canada Limited (AECL), at its Chalk River Laboratory, generates from 3000 to 5000 L/year of high-level fissile waste solution from the production of 99Mo. In this Mo process, highly enriched uranium (93 wt % 235U, total uranium basis) contained in uranium-aluminum alloy target rods is irradiated to produce the 99Mo product. The targets are removed from the reactor and dissolved in a mercury nitrate-catalyzed reaction with nitric acid. The 99Mo product is then recovered by passing the solution through an alumina (Al2O3) column. During discussions with personnel from the Oak Ridge National Laboratory (ORNL) on September 10, 1992, the ORNL-developed technology formerly applied to the solidification of aqueous uranium waste (Consolidated Edison Uranium Solidification Program or CEUSP) was judged potentially applicable to the AECL 99Mo waste. Under a Work-for-Others contract (no. ERD-92-1132), which began May 24, 1993, ORNL was tasked to determine the feasibility of applying the CEUSP (or a similar) calcination process to solidify AECL's 99Mo waste for > 30 years of safe dry storage. This study was to provide sufficient detailed information on the applicability of a CEUSP-type waste solidification process to allow AECL to select the process which best suited its needs. As with the CEUSP process, evaporation of the waste and a simultaneously partial destruction of acid by reaction with formaldehyde followed by in situ waste can thermal denitration waste was chosen as the best means of solidification. Unlike the CEUSP material, the 99Mo waste has a considerable number of problem volatile and semivolatile constituents which must be recovered in the off-gas treatment system. Mercury removal before calcination was seen as the best option

  16. Chemistry of application of calcination/dissolution to the Hanford tank waste inventory

    International Nuclear Information System (INIS)

    Approximately 330,000 metric tons of sodium-rich radioactive waste originating from separation of plutonium from irradiated uranium fuel are stored in underground tanks at the Hanford Site in Washington State. Fractionation of the waste into low-level waste (LLW) and high-level waste (HLW) streams is envisioned via partial water dissolution and limited radionuclide extraction operations. Under optimum conditions, LLW would contain most of the chemical bulk while HLW would contain virtually all of the transuranic and fission product activity. Calcination at around 850 C, followed by water dissolution, has been proposed as an alternative initial treatment of Hanford Site waste to improve waste dissolution and the envisioned LLW/HLW split. Results of literature and laboratory studies are reported on the application of calcination/dissolution (C/D) to the fractionation of the Hanford Site tank waste inventory. Both simulated and genuine Hanford Site waste materials were used in the lab tests. To evaluation confirmed that C/D processing reduced the amount of several components from the waste. The C/D dissolutions of aluminum and chromium allow redistribution of these waste components from the HLW to the LLW fraction. Comparisons of simple water-washing with C/D processing of genuine Hanford Site waste are also reported based on material (radionuclide and chemical) distributions to solution and solid residue phases. The lab results show that C/D processing yielded superior dissolution of aluminum and chromium sludges compared to simple water dissolution. 57 refs., 26 figs., 18 tabs

  17. Surface complexation modeling calculation of Pb(II) adsorption onto the calcined diatomite

    Science.gov (United States)

    Ma, Shu-Cui; Zhang, Ji-Lin; Sun, De-Hui; Liu, Gui-Xia

    2015-12-01

    Removal of noxious heavy metal ions (e.g. Pb(II)) by surface adsorption of minerals (e.g. diatomite) is an important means in the environmental aqueous pollution control. Thus, it is very essential to understand the surface adsorptive behavior and mechanism. In this work, the Pb(II) apparent surface complexation reaction equilibrium constants on the calcined diatomite and distributions of Pb(II) surface species were investigated through modeling calculations of Pb(II) based on diffuse double layer model (DLM) with three amphoteric sites. Batch experiments were used to study the adsorption of Pb(II) onto the calcined diatomite as a function of pH (3.0-7.0) and different ionic strengths (0.05 and 0.1 mol L-1 NaCl) under ambient atmosphere. Adsorption of Pb(II) can be well described by Freundlich isotherm models. The apparent surface complexation equilibrium constants (log K) were obtained by fitting the batch experimental data using the PEST 13.0 together with PHREEQC 3.1.2 codes and there is good agreement between measured and predicted data. Distribution of Pb(II) surface species on the diatomite calculated by PHREEQC 3.1.2 program indicates that the impurity cations (e.g. Al3+, Fe3+, etc.) in the diatomite play a leading role in the Pb(II) adsorption and dominant formation of complexes and additional electrostatic interaction are the main adsorption mechanism of Pb(II) on the diatomite under weak acidic conditions.

  18. Genesis of Cr(VI) in Sri Lankan soils and its adsorptive removal by calcined gibbsite

    Science.gov (United States)

    Rajapaksha, A. U.; Wijesundara, D. M.; Vithanage, M. S.; Ok, Y. S.

    2012-12-01

    Hexavalent chromium is highly toxic to biota and considered as a priority pollutant. Industrial sources of Cr(VI) include leather tanning, plating, electroplating, anodizing baths, rinse waters, etc. In addition, weathering of ultramafic rocks rich in chromium, such as serpentine, is known to Cr(VI) sources into natural water. The Cr(III) is the most stable in the environment, however, conversion of Cr(III) into Cr(VI) occurs in soil due to presence of naturally occurring minerals such as manganese dioxides. We investigated the amount of Cr(VI) recorded from the soils from anthropogenically and naturally contaminated soils (serpentine soils) in Sri Lanka and the removal efficacy of Cr(VI) by calcined gibbsite (Al oxides). The effect of pH on Cr(VI) adsorption was determined by adjusting the pH in the range of 4-10. In the experiments, the adsorbent concentration was kept at 1 g/l of solution containing 10 mg/l Cr(VI) at 25 0C. Total chromium recorded were around 11,000 mg kg-1 and 6,000 mg kg-1 for serpentine soil and tannery waste-contaminated soil, respectively. Although total Cr was high in the contaminated soils, Cr(VI) concentration was only about 28 mg kg-1 and 210 mg kg-1 in the serpentine and tannery soils, respectively. The calcined gibbsite has maximum adsorption of 85 % around pH 4 and adsorption generally decreased with increase of pH.

  19. Stabilized γ-BIMNVOX solid electrolyte: Ethylene glycol–citrate sol–gel synthesis, microwave-assisted calcination, and structural and electrical characterization

    Energy Technology Data Exchange (ETDEWEB)

    Al-Areqi, Niyazi A.S., E-mail: niyazi.alareqi@gmail.com [Department of Chemistry, Faculty of Applied Science, Taiz University, Taiz, Republic of Yemen (Yemen); Beg, Saba [Department of Chemistry, Aligarh Muslim University, Aligarh 202002 (India); Al-Alas, Ahlam [Department of Chemistry, Faculty of Applied Science, Taiz University, Taiz, Republic of Yemen (Yemen); Hafeez, Shehla [Department of Chemistry, Aligarh Muslim University, Aligarh 202002 (India)

    2013-12-25

    Highlights: •γ-BIMNVOX was synthesized by ethylene glycol–citrate sol–gel route. •γ-BIMNVOX crystallizes by 25-min microwave-assisted calcination. •Smaller particle sizes for microwave calcined BIMNVOX samples. •Best oxide-ion performance for microwave calcined BIMNVOX samples. -- Abstract: Samples of γ-BIMNVOX (Bi{sub 2}V{sub 1−x}Mn{sub x}O{sub 5.5−x/2}; 0.13 ⩽ x ⩽ 0.20) system were synthesized by an ethylene glycol–citrate sol–gel route. The resulting xerogels were then calcined by the microwave heating using a modified domestic microwave oven operated at 2.45 GHz. Microwave-assisted calcination samples in comparison with other conventionally calcined samples were characterized in terms of phase crystallization, stabilization and particle size using simultaneous thermogravimetric–differential thermal analysis (TG–DTA), X-ray powder diffraction (XRPD) and scanning electron microscopy (SEM). The AC impedance spectroscopy was employed for electrical characterization. It was found that the microwave-assisted calcination route successfully produces better crystalline stabilized γ-BIMNVOX samples with appreciably small average particle sizes after only 25 min of microwave heating. The electrical properties of microwave calcined γ-BIMNVOX system make it an advanced low-temperature solid electrolyte suitable for use in oxide-ion based electrochemical applications.

  20. Description of a pilot plant to produce a pelleted form from simulated ICPP high-level calcined wastes

    International Nuclear Information System (INIS)

    The pilot plant uses techniques learned in the laboratory to combine calcine with solid and liquid binders to form hard, leach-resistant pellets. The pilot plant is designed to process up to 25 kg/h of calcine and will provide information necessary to verify the operational feasibility of pelletizing calcined waste. Also, information for the design of a possible full-scale pelletizing plant will be obtained. All components of the pelletizing operations are described. The solids feed system consists of two loss-in-weight feeders: one for calcine and one for solid binders. Intimate mixing of the solids is accomplished in a screw mixer-feeder. A metering pump is used to pump liquid binders to the pelletizer through a spray nozzle. A 12.7 mm mesh, vibro screen separator removes oversize pellets, leaving the pelletizer. A 0-6 kW microwave-heated dryer operating at 150 to 2000C removes moisture from the pellets in about 15 minutes. To impart leach resistance, the pellets are heat treated at 800 to 9000C for 1 to 2 hrs in a kiln. Pellets move down through a set of 6 to 8 stacked, rotating trays inside the kiln. Pellets are collected from the heat treater and tested for strength and leach resistance. An off-gas system cools and removes dust present in the off-gas from the pilot plant. 20 figures

  1. Influence of calcination temperature on sol-gel synthesized single-phase bismuth titanate for high dielectric capacitor applications

    Energy Technology Data Exchange (ETDEWEB)

    Thiruramanathan, Pandirengan; Marikani, Arumugam [Mepco Schlenk Engineering College, Tamil Nadu (India). Dept. of Physics; Madhavan, Durairaj [Mepco Schlenk Engineering College, Tamil Nadu (India). Dept. of Chemistry; Bharadwaj, Suresh; Awasthi, Anand Mohan [UGC-DAE Consortium for Scientific Research, Indore (India). Thermodynamics Lab.

    2016-05-15

    An inexpensive sol-gel combustion method using citric acid as fuel has been used to synthesize bismuth titanate, Bi{sub 4}Ti{sub 3}O{sub 12} nanopowders. Thermogravimetric analysis proved that a calcination temperature of 900 C is sufficient for the preparation of single-phase bismuth titanate. X-ray diffraction and Fourier transform infrared spectroscopy are used to examine the influence of calcination temperature on the structural growth of the Bi{sub 4}Ti{sub 3}O{sub 12} nanopowder. The average crystallite size estimated by using the Scherrer method and the Williamson-Hall method was found to increase with calcination temperature. Photoluminescence behavior as a function of calcination temperature was observed at two different excitation wavelengths of 300 nm and 420 nm. The morphology of the particles analyzed using images obtained from field emission scanning electron microscopy displayed irregular, random sized, and spherical-shaped structures. The stoichiometry and purity of the nanopowder are confirmed by energy-dispersive spectroscopy. The broadband dielectric results established the highest dielectric constant (ε{sub r} = 450) for a frequency of 100 Hz achieved with a potential capacitance of 138 pF m{sup -2}. This establishes Bi{sub 4}Ti{sub 3}O{sub 12} as a promising dielectric material for achieving high energy density capacitors for the next-generation passive devices.

  2. Effect of Calcination Temperature on Catalytic Activity and Textual Property of Cu/HMOR Catalysts in Dimethyl Ether Carbonylation Reaction

    Institute of Scientific and Technical Information of China (English)

    Xue Zhang; Yu-ping Li; Song-bai Qiu; Tie-jun Wang; Long-long Ma; Qi Zhang; Ming-yue Ding

    2013-01-01

    The effect of calcination temperature on the catalytic activity for the dimethyl ether (DME) carbonylation into methyl acetate (MA) was investigated over mordenite supported copper (Cu/HMOR) prepared by ion-exchange process.The results showed that the catalytic activity was obviously affected by the calcination temperature.The maximal DME conversion of 97.2% and the MA selectivity of 97.9% were obtained over the Cu/HMOR calcined at 430 ℃ under conditions of 210 ℃,1.5 MPa,and GSHV of 4883 h-1.The obtained Cu/HMOR catalysts were characterized by powder X-ray diffraction,N2 absorption,NH3 temperature program desorption,CO temperature program desorption,and Raman techniques.Proper calcination temperature was effective to promote copper ions migration and diffusion,and led the support HMOR to possess more acid activity sites,which exhibited the complete decomposing of copper nitrate,large surface area and optimum micropore structure,more amount of CO adsorption site and proper amount of weak acid centers.

  3. Hydrothermal synthesis of boehmites with various particle sizes and transition to α-Al2O3 powders by calcination

    Institute of Scientific and Technical Information of China (English)

    LI; Shao-hua; YUAN; Fang-li; HU; Peng; KE; Jia-jun

    2005-01-01

    Boehmite powders with various particle sizes have been prepared by hydrothermal method and the α-Al2 O3 powders yielded after subsequent calcination have been studied. Dispersive crystalline boehmite powders of 30-100 nm, 0.4-0. 6μm and 1μm in size were obtained respectively by changing the hydrothermal precursors and the pH value of hydrothermal slurry. Calcination of boehmite powders of 30-100 nm at 1250℃ for 1h resulted in the formation of single-phase α-Al2O3,and the products consisted of vermicular particles. The boehmite powders of 0.4-0.6μm were also fully converted to α-Al2O3 at 1250℃, and the products consisted of plate-like particles with the same size of 0. 4-0. 6μm. The boehmite powders of 1μm calcined at 1350℃ for 2h were still composed of a little proportions of transition aluminas besides α-Al2 O3, and the particles sintered severely. The reaction processes for the formation of crystalline boehmites under hydrothermal conditions and α-Al2O3 powders during calcination have been discussed.

  4. Effect of calcination temperature and reaction conditions on methane partial oxidation using lanthanum-based perovskite as oxygen donor

    Institute of Scientific and Technical Information of China (English)

    DAI Xiaoping; YU Changchun; LI Ranjia; WU Qiong; SHI Kaijiao; HAO Zhengping

    2008-01-01

    We investigated the effect of calcination temperature, reaction temperature, and different amounts of replenished lattice oxygen on the partial oxidation of methane (POM) to synthesis gas using perovskite-type LaFeO3 oxide as oxygen donor instead of gaseous oxygen, which was prepared by the sol-gel method, and the oxides were characterized by XRD, TG/DTA, and BET. The results indicated that the particle size increased with the calcination temperature increasing, while BET and CH4 conversion declined with the calcination temperature increasing using LaFeO3 oxide as oxygen donor in the absence of gaseous oxygen. CO selectivity remained at a high level such as above 92%, and increased slightly as the calcination temperature increased. Exposure of LaFeO3 oxides to methane atmosphere enhanced the oxygen migration of in the bulk with time online owing to the loss of lattice oxygen and reduction of the oxidative stated Fe ion simultaneously. The high reaction temperature was favorable to the migration of oxygen species from the bulk toward the surface for the synthesis gas production with high CO selectivity. The product distribution and evolution for POM by sequential redox reaction was determined by amounts of replenished lattice oxygen with gaseous oxygen. The optimal process should decline the total oxidation of methane, and increase the selectivity of partial oxidation of methane.

  5. Influence of calcinations temperature on physical properties of the nanocomposites containing spinel and CuO phases

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Manish [Department of Physics, Motilal Nehru National Institute of Technology, Allahabad, Allahabad 211004 (India); Ojha, Animesh K., E-mail: animesh_r1776@rediffmail.co [Department of Physics, Motilal Nehru National Institute of Technology, Allahabad, Allahabad 211004 (India); Chaubey, S. [Department of Physics, Motilal Nehru National Institute of Technology, Allahabad, Allahabad 211004 (India); Sharma, Prashant K.; Pandey, Avinash C. [Nanophosphor Application Centre, University of Allahabad, Allahabad 211002 (India)

    2010-04-02

    Nanocomposites containing spinel and CuO phases have been synthesized by sol-gel method using Cu(II), Ni(II) and Fe(III) in a basic medium. The effect of calcinations temperature on the physical properties of the nanocomposites has been investigated by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), micro-Raman spectroscopy (RS), differential scanning calorimetery (DSC)/thermogravemetric analysis (TGA), diffuse reflectance spectroscopy (DRS), scanning electron microscope (SEM), high resolution transmission electron microscope (HR-TEM) and vibrating sample magnetometer (VSM). The XRD pattern of nanocomposites synthesized at different calcinations temperature reveals spinel and CuO phases. The particle size of the nanocomposites is increasing with increasing the calcinations temperature. The band gap of synthesized nanocomposites has been calculated using DRS method. The prepared nanocomposites exhibit semiconducting nature with band gap values, 1.9-2.24 eV. The magnetic properties of nanocomposites are also measured at room temperature and the values of saturation magnetization (Ms), remanent magnetization (Mr) and coercivity are found enhanced with the calcinations temperature.

  6. Development and Testing of the Advanced CHP System Utilizing the Off-Gas from the Innovative Green Coke Calcining Process in Fluidized Bed

    Energy Technology Data Exchange (ETDEWEB)

    Chudnovsky, Yaroslav; Kozlov, Aleksandr

    2013-08-15

    Green petroleum coke (GPC) is an oil refining byproduct that can be used directly as a solid fuel or as a feedstock for the production of calcined petroleum coke. GPC contains a high amount of volatiles and sulfur. During the calcination process, the GPC is heated to remove the volatiles and sulfur to produce purified calcined coke, which is used in the production of graphite, electrodes, metal carburizers, and other carbon products. Currently, more than 80% of calcined coke is produced in rotary kilns or rotary hearth furnaces. These technologies provide partial heat utilization of the calcined coke to increase efficiency of the calcination process, but they also share some operating disadvantages. However, coke calcination in an electrothermal fluidized bed (EFB) opens up a number of potential benefits for the production enhancement, while reducing the capital and operating costs. The increased usage of heavy crude oil in recent years has resulted in higher sulfur content in green coke produced by oil refinery process, which requires a significant increase in the calcinations temperature and in residence time. The calorific value of the process off-gas is quite substantial and can be effectively utilized as an “opportunity fuel” for combined heat and power (CHP) production to complement the energy demand. Heat recovered from the product cooling can also contribute to the overall economics of the calcination process. Preliminary estimates indicated the decrease in energy consumption by 35-50% as well as a proportional decrease in greenhouse gas emissions. As such, the efficiency improvement of the coke calcinations systems is attracting close attention of the researchers and engineers throughout the world. The developed technology is intended to accomplish the following objectives: - Reduce the energy and carbon intensity of the calcined coke production process. - Increase utilization of opportunity fuels such as industrial waste off-gas from the novel

  7. Phase and morphology evolution of (Na1-xKxNbO3 powders related to calcinations and K2CO3 content

    Directory of Open Access Journals (Sweden)

    Steven J. Milne

    2007-03-01

    Full Text Available Sodium-potassium niobate ((Na1-xKxNbO3 powders with x = 0.2, 0.4, 0.6 and 0.8 were prepared following the conventional mixed oxide method and characterized by TG-DTA, XRD and SEM techniques.The effects of calcination temperature, dwell time and K2CO3 content on phase formation behavior and morphology of the powders were investigated. The calcination temperature and dwell time were found tohave a pronounced effect on the phase formation of the calcined sodium-potassium niobate powders. It was found that the crystallized phase depended on calcination conditions. The high calcination temperature andlong dwell time clearly favored particle growth and the formation of large and hard agglomerates. All the (Na1-xKxNbO3 powders showed a similar orthorhombic phase structure. The K2CO3 content significantlyaffected the calcination temperature and particle size and shape. Large particle size, cubic shape and a lower calcined condition were observed in (Na1-xKxNbO3 powder with low K2CO3 content (x = 0.2.

  8. Effect of calcining temperature and time on the characteristics of Sb-doped SnO2 nanoparticles synthesized by the sol-gel method

    Institute of Scientific and Technical Information of China (English)

    Xiaohua Zhong; Baoping Yang; Xiaoliang Zhang; Junhong Jia; Gewen Yi

    2012-01-01

    Spherical Sb-doped SnO2 (ATO) nanoparticles were synthesized by the sol-gel route,employing SnCl4·5H2O and SbCl3 as precursors in an ethanol solution.The influences of the calcining temperature and calcining time on the crystallite size,crystallinity,lattice parameters,lattice distortion ratio and the resistivity of the ATO nanoparticles were synthetically investigated.The results suggested that the ATO nanoparticles were crystallized in a tetragonal cassiterite structure of SnO2 with a highly (110)-plane-preferred orientation.The calcining temperature had a dominating effect on the crystallite size,crystallinity,lattice distortion ratios and resistivity of the ATO.As the calcining temperature increased,the average crystallite size increased,the crystallinity was promoted accompanied by a decrease in the lattice distortion ratio and a corresponding decrease in the resistivity of the ATO.X-ray diffraction (XRD) and Fourier transform infrared spectrophotometer (FTIR) analysis revealed that Sb ions could not entirely supplant the Sn ions in the SnO2 lattice for a calcining time of less than 0.5 h,even at a calcining temperature of 1000℃.The ATO nanoparticles calcined at 1000℃ for 3.0h possessed the lowest resistivity of 10.18Ωcm.

  9. [Based on Curing Age of Calcined Coal Gangue Fine Aggregate Mortar of X-Ray Diffraction and Scanning Electron Microscopy Analysis].

    Science.gov (United States)

    Dong, Zuo-chao; Xia, Jun-wu; Duan, Xiao-mu; Cao, Ji-chang

    2016-03-01

    By using X-ray diffraction (XRD) and environmental scanning electron microscope (SEM) analysis method, we stud- ied the activity of coal gangue fine aggregate under different calcination temperature. In view of the activity of the highest-700 degrees C high temperature calcined coal gangue fine aggregate mortar of hydration products, microstructure and strength were discussed in this paper, and the change laws of mortar strength with curing age (3, 7, 14, 28, 60 and 90 d) growth were analyzed. Test results showed that coal gangue fine aggregate with the increase of calcination temperature, the active gradually increases. When the calcination temperature reaches 700 degrees C, the activity of coal gangue fine aggregate is the highest. When calcining temperature continues to rise, activity falls. After 700 degrees C high temperature calcined coal gangue fine aggregate has obvious ash activity, the active components of SiO2 and Al2 O3 can be with cement hydration products in a certain degree of secondary hydration reaction. Through on the top of the activity of different curing age 700 degrees C high temperature calcined coal gangue fine aggregate mortar, XRD and SEM analysis showed that with the increase of curing age, secondary hydration reaction will be more fully, and the amount of hydration products also gradually increases. Compared with the early ages of the cement mortar, the products are more stable hydration products filling in mortar microscopic pore, which can further improve the microstructure of mortar, strengthen the interface performance of the mortar. The mortar internal structure is more uniform, calcined coal gangue fine aggregate and cement mortar are more of a strong continuous whole, which increase the later strength of hardened cement mortar, 700 degrees C high temperature calcined coal gangue fine aggregate pozzolanic effect is obvious.

  10. Effects of Calcination Temperature on the Acidity and Catalytic Performances of HZSM-5 Zeolite Catalysts for the Catalytic Cracking of n-Butane

    Institute of Scientific and Technical Information of China (English)

    Jiangyin Lu; Zhen Zhao; Chunming Xu; Aijun Duan; Pu Zhang

    2005-01-01

    The acidic modulations of a series of HZSM-5 catalysts were successfully made by calcination at different treatment temperatures, i.e. 500, 600, 650, 700 and 800 ℃, respectively. The results indicated that the total acid amounts, their density and the amount of B-type acid of HZSM-5 catalysts rapidly decreased, while the amounts of L-type acid had almost no change and thus the ratio of L/B was obviously enhanced with the increase of calcination temperature (excluding 800 ℃). The catalytic performances of modified HZSM-5 catalysts for the cracking of n-butane were also investigated. The main properties of these catalysts were characterized by means of XRD, N2 adsorption at low temperature, NH3-TPD, FTIR of pyridine adsorption and BET surface area measurements. The results showed that HZSM-5 zeolite pretreated at 800 ℃ had very low catalytic activity for n-butane cracking. In the calcination temperature range of 500-700 ℃, the total selectivity to olefins, propylene and butene were increased with the increase of calcination temperature, while, the selectivity for arene decreased with the calcination temperature.The HZSM-5 zeolite calcined at 700 ℃ produced light olefins with high yield, at the reaction temperature of 650 ℃ the yields of total olefins and ethylene were 52.8% and 29.4%, respectively. Besides, the more important role is that high calcination temperature treatment improved the duration stability of HZSM-5zeolites. The effect of calcination temperature on the physico-chemical properties and catalytic performance of HZSM-5 for cracking of n-butane was explored. It was found that the calcination temperature had large effects on the surface area, crystallinity and acid properties of HZSM-5 catalyst, which further affected the catalytic performance for n-butane cracking.

  11. Chloride adsorption by calcined layered double hydroxides in hardened Portland cement paste

    KAUST Repository

    Yoon, Seyoon

    2014-06-01

    This study investigated the feasibility of using calcined layered double hydroxides (CLDHs) to prevent chloride-induced deterioration in reinforced concrete. CLDHs not only adsorbed chloride ions in aqueous solution with a memory effect but also had a much higher binding capacity than the original layered double hydroxides (LDHs) in the cement matrix. We investigated this adsorption in hardened cement paste in batch cultures to determine adsorption isotherms. The measured and theoretical binding capacities (153 mg g -1 and 257 mg g-1, respectively) of the CLDHs were comparable to the theoretical capacity of Friedel\\'s salt (2 mol mol-1 or 121 mg g-1), which belongs to the LDH family among cementitious phases. We simulated chloride adsorption by CLDHs through the cement matrix using the Fickian model and compared the simulation result to the X-ray fluorescence (XRF) chlorine map. Based on our results, it is proposed that the adsorption process is governed by the chloride transport through the cement matrix; this process differs from that in an aqueous solution. X-ray diffraction (XRD) analysis showed that the CLDH rebuilds the layered structure in a cementitious environment, thereby demonstrating the feasibility of applying CLDHs to the cement and concrete industries. © 2014 Published by Elsevier B.V. All rights reserved.

  12. Draft environmental assessment -- Closure of the Waste Calcining Facility (CPP-633), Idaho National Engineering Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Braun, J.B.; Irving, J.S.; Staley, C.S.; Stanley, N.

    1996-04-01

    The DOE-Idaho Operations Office has prepared an environmental assessment (EA) to analyze the environmental impacts of closing the Waste Calcining Facility (WCF) at the Idaho National Engineering Laboratory (INEL). The purpose of the action is to reduce the risk of radioactive exposure and release of radioactive and hazardous constituents and eliminate the need for extensive long-term surveillance and maintenance. DOE has determined that the closure is needed to reduce these risks to human health and the environment and to comply with Resource Conservation and Recovery Act requirements. The WCF closure project is described in the DOE Programmatic Spent Nuclear Fuel Management and Idaho National Engineering Laboratory Environmental Restoration and Waste Management Programs Final Environmental Impact Statement (Programmatic EIS). DOE determined in the Programmatic EIS Record of Decision (ROD) that certain actions would be implemented and other actions deferred. The EA examined the potential environmental impacts of the proposed action and evaluated reasonable alternatives, including the no action alternative in accordance with the Council on Environmental Quality Regulations. Based on the analysis in the EA, the action will not have a significant effect on the human environment.

  13. Stabilization of lead and copper contaminated firing range soil using calcined oyster shells and fly ash.

    Science.gov (United States)

    Moon, Deok Hyun; Park, Jae-Woo; Cheong, Kyung Hoon; Hyun, Seunghun; Koutsospyros, Agamemnon; Park, Jeong-Hun; Ok, Yong Sik

    2013-12-01

    A stabilization/solidification treatment scheme was devised to stabilize Pb and Cu contaminated soil from a firing range using renewable waste resources as additives, namely waste oyster shells (WOS) and fly ash (FA). The WOS, serving as the primary stabilizing agent, was pre-treated at a high temperature to activate quicklime from calcite. Class C FA was used as a secondary additive along with the calcined oyster shells (COS). The effectiveness of the treatment was evaluated by means of the toxicity characteristic leaching procedure (TCLP) and the 0.1 M HCl extraction tests following a curing period of 28 days. The combined treatment with 10 wt% COS and 5 wt% FA cause a significant reduction in Pb (>98 %) and Cu (>96 %) leachability which was indicated by the results from both extraction tests (TCLP and 0.1 M HCl). Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX) analyses are used to investigate the mechanism responsible for Pb and Cu stabilization. SEM-EDX results indicate that effective Pb and Cu immobilization using the combined COS-FA treatment is most probably associated with ettringite and pozzolanic reaction products. The treatment results suggest that the combined COS-FA treatment is a cost effective method for the stabilization of firing range soil.

  14. Sorption of H₃BO₃/B(OH)₄⁻ on calcined LDHs including different divalent metals.

    Science.gov (United States)

    Qiu, Xinhong; Sasaki, Keiko; Osseo-Asare, Kwadwo; Hirajima, Tsuyoshi; Ideta, Keiko; Miyawaki, Jin

    2015-05-01

    LDHs with different divalent metals (Zn-LDH, Mg-LDH and Ca-LDH) have been synthesized and produced calcined LDHs (Zn-CLDH, Mg-CLDH and Ca-CLDH) for borate removal. Based on XRD, SEM, BET, (27)Al NMR, CO2-TPD, and (11)B NMR, detailed characterization of different CLDHs before and after reaction with the boron species was systematically performed. The surface area, basicity and the particle charge of the different CLDHs, which are related to the hydration and regeneration, were markably influenced by the nature of the divalent metals. Transformation of crystal phases and the types of boron species adsorbed by the different CLDHs varied as time changed. The regeneration of Ca-CLDH required the shortest time. However, Ca-LDH decomposed to release Ca(2+) ions, forming ettringite with borate. Zn-CLDH also rapidly transformed into Zn-LDH. During this reconstruction, B(OH)4(-) was intercalated into the interlayer of Zn-LDHs, which is the predominant mechanism of borate removal by Zn-CLDH. Increase in the initial pH caused a competition between borate and OH(-) so that the removal efficiency of borate by Zn-CLDH decreased. For Mg-CLDH, surface complexation and electrostatic attraction were included in the first stage, immobilizing boric acid into Mg(OH)2 and attracting borate as interlayer anionic species into the new forming Mg-LDHs in the second stage. PMID:25618238

  15. Development of a high energy efficient pressure calciner. Final report, June 1, 1994--July 31, 1997

    Energy Technology Data Exchange (ETDEWEB)

    Bush, J.F.

    1997-12-18

    During the life of this contract, the design, procurement, and construction of a pilot, self-fluidizing, pressure calciner for the production of smelting grade alumina was completed. Initial operating characteristics were determined, and the first half of the first DOX was completed. A design capacity of at least 100 kg/hr of product had been chosen to insure a 100:1 maximum scale-up ratio for the semi-commercial unit. Detailed numerical analysis was made for the heat exchanger design to set the active tube length at 8.5 m (28 ft). The instrumentation and data logging system was designed to obtain the detailed engineering parameters for design of the semi-commercial unit. The pressure feed, discharge, and burner systems were chosen from existing commercial designs to reduce the development work required. Auxiliary equipment, steam condenser, cooling tower, and product cooler, were chosen to simplify operation during the experimental program. Self-fluidizing capabilities were determined to exist both from temperature profiles and heat transfer coefficient calculations.

  16. Mineral Phase and Physical Properties of Red Mud Calcined at Different Temperatures

    Directory of Open Access Journals (Sweden)

    Chuan-sheng Wu

    2012-01-01

    Full Text Available Different characterizations were carried out on red mud uncalcined and samples calcined in the range of 100°C–1400°C. In the present paper, the phase composition and structural transition of red mud heated from room temperature are indicated by XRD, TG-DTA, and SEM techniques. The mean particle diameter, density, and bond strength of these samples also have been investigated. The results indicate the decomposition of gibbsite into Al2O3 and H2O between 300°C and 550°C and calcite into CaO and CO2 in the interval of 600–800°C. Tricalcium aluminate and gehlenite are formed in the range of 800–900°C. Combined with the SEM images, the results of physical property testing show that the particle size and the strength each has a continuous rise during the heat treatment from 150°C to 1350°C. But the value of density will undergo a little drop before 450°C and then increases to a higher value at the temperature of 1200°C. These obtained results provide an important base for the further studies of comprehensive utilization of red mud.

  17. Optimization Study on the Leaching of High Iron-Bearing Zinc Calcine After Reduction Roasting

    Science.gov (United States)

    Han, Junwei; Liu, Wei; Qin, Wenqing; Zheng, Yongxing; Luo, Honglin

    2016-02-01

    The selective leaching of zinc from high iron-bearing zinc calcine after reduction roasting was optimized by Taguchi experimental design method. The experimental parameters and their ranges were 303 to 343 K (30 to 70 °C) for leaching temperature ( T), 7 to 15 mL/g for liquid/solid ratio ( L/ S), 70 to 150 g/L for H2SO4 concentration ( C), 5 to 25 minutes for time ( t), and 100 to 500 rpm for stirring speed ( R). The results show that the optimum conditions were 303 K (30 °C), 9 mL/g, 110 g/L, 20 minutes, and 400 rpm, respectively. Under these conditions, about 92.81 pct Zn was extracted and more than 86 pct Fe was reported into the leach residue. L/ S and C had significant effects on the extractions of zinc and iron, while t and R had no significant effects, and T had significant effect on iron extraction but negligible effect on zinc extraction. This indicates that diffusion was not a major control step of the leaching process, and the dissolution of iron was controlled by chemical reaction. The interactive effects of parameters were negligible. The leach residue was mainly composed of Fe3O4 and ZnS, and its particle size was very fine.

  18. Environmental assessment: Closure of the Waste Calcining Facility (CPP-633), Idaho National Engineering Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-07-01

    The U.S. Department of Energy (DOE) proposes to close the Waste Calcining Facility (WCF). The WCF is a surplus DOE facility located at the Idaho Chemical Processing Plant (ICPP) on the Idaho National Engineering Laboratory (INEL). Six facility components in the WCF have been identified as Resource Conservation and Recovery Ace (RCRA)-units in the INEL RCRA Part A application. The WCF is an interim status facility. Consequently, the proposed WCF closure must comply with Idaho Rules and Standards for Hazardous Waste contained in the Idaho Administrative Procedures Act (IDAPA) Section 16.01.05. These state regulations, in addition to prescribing other requirements, incorporate by reference the federal regulations, found at 40 CFR Part 265, that prescribe the requirements for facilities granted interim status pursuant to the RCRA. The purpose of the proposed action is to reduce the risk of radioactive exposure and release of hazardous constituents and eliminate the need for extensive long-term surveillance and maintenance. DOE has determined that the closure is needed to reduce potential risks to human health and the environment, and to comply with the Idaho Hazardous Waste Management Act (HWMA) requirements.

  19. [XPS study on the influence of calcination conditions to cerium ion valence].

    Science.gov (United States)

    Mei, Yan; Yan, Jian-ping; Nie, Zuo-ren

    2010-01-01

    For the system of Ce(NO3)2.6H2O and urea solution during homogeneous precipitation method, X-ray diffraction (XRD), infrared spectrum (IR) and especially X-ray photoelectron spectroscopy (XPS) were used to study and characterize the product structure, variety of cerium ion valence, compound surface character and kernel electronic configurations. The results of XRD and IR showed that calcination temperature had a great effect on the cerium ion valence. The products are orthorhombic Ce2 O(CO3)2.H2O with valence III by using homogeneous precipitation method directly. When heated from the temperature 200 degrees C to 250 degrees C, the product of CeO(CO3)2.H2O with valence VI was finally changed into stable CeO2 with valence IV. XPS was used to study the surface character and kernel electronic configurations of the three different compounds through fine scanning of O(1s), Ce(3d) and Ce(4d) apices, and the results approved that the compounds with different valences are caused by the different valence electronic configurations of the products.

  20. Research about the pozzolanic activity of waste materials from calcined clay

    Directory of Open Access Journals (Sweden)

    Sánchez de Rojas, M. I.

    2001-03-01

    Full Text Available To recycle and reutilise waste materials and find definite applications for their use, it is necessary to have a deep knowledge of them. The aim of this study is to study the possibility of using waste materials from calcined clay, actually ceramic tile, once crushed and grounded, as pozzolanic material. For this purpose, different tests are carried out in order to establish the pozzolanic activity of this material. At the same time, these results are compared to those of other industrial by-products, fly ash and silica fume, which are pozzolanic materials usually employed to elaborate mortars and concretes.

    Para llevar a cabo labores encaminadas al reciclado y revalorización de residuos es necesario un conocimiento profundo de los mismos, de forma que se busquen aplicaciones concretas de uso. El objetivo de este estudio es investigar la posibilidad de utilizar materiales de desecho procedentes de arcilla cocida, concretamente teja cerámica, una vez triturada y molida, como puzolana. Para ello, se efectúan diferentes ensayos dirigidos a establecer la actividad puzolanica del material. A su vez, estos resultados son comparados con otros residuos industriales, ceniza volante y humo de sílice, habituales en la elaboración de morteros y hormigones.

  1. Strength of Limestone-based Non-calcined Cement and its Properties

    Institute of Scientific and Technical Information of China (English)

    LIN Zongshou; ZHAO Qian

    2009-01-01

    A new type of cement was prepared with ground limestone powder,blastfurnace slag,steel slag and gypsum without calcination.The fraction of ground limestone powder in the cement was as high as 40 wt%-60 wt%without Portland clinker.All of its physical properties can meet the requirements of masonry cement standards.The impact of limestone content on physical properties of the cement and determined its impact on law was investigated.The steel slag can excit the aquation activity of this cement effectively,and the influence of its quantity on the strength of the materials was studied,which shows that the optimum quantity of mixing is 10%.By way of changing the different content of the lime stone by quartzy sample,the law of the compression strength and the PH value was determined,confirming that the lime stone can promote the early aquation of the slag and improve the early strength.The main hydration product of this cement is calcium aluminate hydrate, ettringite and calcium silicate hydrate,as indicated by XRD and SEM analysis.

  2. A laboratory scale study on arsenic(V) removal from aqueous medium using calcined bauxite ore

    Institute of Scientific and Technical Information of China (English)

    Debasish Mohapatra; Debaraj Mishra; Kyung Ho Park

    2008-01-01

    The present work deals with the As(V) removal from an aqueous medium by calcined refractory grade bauxite (CRB) as a function of solution pH,time,As(V) concentration and temperature.The residual As(V) was lowered from 2 mg/L to below 0.01 mg/L in the optimum pH range 4.0-7.0 using a 5 g/L CRB within 3 h contact time.The adsorption data fits well with Langmuir isotherm and yielded Langmuir monolayer capacity of 1.78 mg As(V)/g of CRB at pH 7.0.Presence of anions such as silicate and phosphate decreased As(V) adsorption efficiency.An increase temperature resulted a decrease in the amount of As(V) adsorbed by 6%.The continuous fixed bed column study showed that at the adsorbent bed depth of 30 cm and residence time of 168 min.the CRB was capable of treating 340 bed volumes of As(V) spiked water (Co=2 mg/L)before breakthrough (Ge=0.01 mg/L).This solid adsorbent,although not reusable,call be considered for design of adsorption columns as an efficiency arsenic adsorption media.

  3. Surface modification of calcined kaolin with toluene diisocyanate based on high energy ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Yongbing; Chen, Hongling, E-mail: hlchen@njut.edu.cn; Lin, Jinbin; Ji, Yan

    2013-11-01

    The surface of calcined kaolin particle was modified with toluene diisocyanate (TDI) by using high energy ball milling. The prepared hybrids were characterized by FT-IR, MAS NMR, thermal analysis (TGA-DSC), static water contact angle (CA), apparent viscosity and transmission electron microscopy (TEM). FT-IR and MAS NMR spectra demonstrated that TDI molecules were chemically anchored to kaolin surface after modification. The results of thermal analysis showed that the maximum grafting ratio reached up to 446.61% when the mass ratio of TDI/kaolin was 0.5:1.0, and CA measurements revealed that the resultant hybrids exhibited strong hydrophobicity (148.82°). Apparent viscosity and TEM were employed to examine the dispersion properties of blank and modified kaolin particles in poly (dimenthylsiloxane) matrix. The results illustrated that the dispersion stability depended strongly on the grafting ratio of TDI, neither too low nor too high achieved uniform and stable dispersion, and the favorable grafting ratio was obtained when the mass ratio of TDI/kaolin was 0.2:1.0. Further modification of TDI/kaolin (mass ration of TDI/kaolin, 1.0:1.0) particles with bis(aminopropyl)-terminated-poly(dimethylsiloxane) (APS) was also investigated. TEM evidenced that the dispersion properties of the obtained TDI/APS/kaolin particles were remarkably improved in octamethyl cyclotetrasiloxane compared with the original TDI/kaolin particles.

  4. Advanced mineral calciner for regeneration of lime. Final report, March 1995--May 1997

    Energy Technology Data Exchange (ETDEWEB)

    Namazian, M.; Nickeson, R.; Lovas, B.; Miller, G.; Kelly, J.

    1997-12-31

    There are approximately 800 pulp, paper and paperboard mills in the United States. Pulp and paper is the ninth largest industry in US, uses 2.8 quads of energy per year and ranks third among all domestic US industries in the cost of energy consumed. A significant fraction of the energy consumed in pulp and paper plants is needed to recover chemicals that are used in breaking down the wood chips into pulp. In particular, 0.1 quads of energy per year are used to regenerate lime. Furthermore, pulp and paper plant operations generate 9,870 tons of NOx per year. Additionally over two million tons of spent lime are sent to landfills each year. In addition, growth in paper demand and changes in plant processes (e.g., bleaching), as a result of environmental pressures, will continue to drive the need for more lime regeneration capacity. Unless the increased capacity can be delivered productively and inexpensively, the growth in pulp and paper may occur in overseas markets. Furthermore, if new environmental constraints cannot be met at low cost, existing US pulp and paper production capacity may also move off-shore. The advanced mineral calciner (AMC) technology was developed to address this lime regeneration need. Prior to describing the technology, and the program of work that was used to test the concept, conventional lime regeneration systems and their limitations are described.

  5. Effect of the calcining temperature on the porosity of the titanium dioxide powders obtained by Polymeric Precursor Method

    International Nuclear Information System (INIS)

    Ceramics materials obtained by Polymeric Precursor Method exhibit mechanisms of the pore formation and elimination dependents on the decomposition kinetics of the residual organic matter of the polyester. The mechanism of pore elimination seems to occur by disrupting of the wall among the pores because it leads to the consequent pore coalescence and increasing in pore volume, which posses higher pore diameters. In this case, it was observed that the porosity decreasing occurs by pore wall moving after that the residual organic matter is eliminated from the pore inside. The pore diameter associated to the highest volume desorption occurred for the material obtained after calcining at 450°C is approximately 1,7 nm, what seems to be related to the amorphous carbon accumulated inside the pores, once that the pore volume decreases more effectively for the material obtained by calcining at 550°C, making the maximum volume situates at 2,0 nm. (author)

  6. Characterization and use of in natura and calcined rice husks for biosorption of heavy metals ions from aqueous effluents

    Directory of Open Access Journals (Sweden)

    M. G. A. Vieira

    2012-09-01

    Full Text Available Heavy metal removal by adsorption using rice husks as a bioadsorbent was evaluated as an alternative for wastewater treatment. Batch equilibrium experiments and kinetic sorption studies were performed using monocomponent solutions of Ni(II, Cd(II, Zn(II, Pb(II and Cu(II in surface samples of in natura(RH and calcined rice husks (RHA. RHA showed higher potential for removing lead and copper. Experimental data for adsorption isotherms of lead and copper were adjusted by Langmuir, Freundlich and Dubinin-Radushkevick (D-R models, being better represented by the Langmuir model. The calcination of RH increased its surface area, improving its adsorption properties. From a morphological analysis obtained by SEM and diffraction patterns (XRD, a longitudinal fibrous and amorphous structure was observed for RH. TGA resultsindicated a total mass loss of around 60% for RH and 24.5% for RHA.

  7. Studies of the Catalytic Activity and Deactivation of Calcined Layered Double Hydroxides in the Reaction of Ethanol with Propylene Oxide

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The reaction of ethanol with propylene oxide over calcined layered double hydroxides(CLDH) was investigated. The results show that CLDH has a good activity and a good selectivity, but the activity and the selectivity of CLDH decrease when CLDH reforms LDH- the so called "memory effect". The influence of the "memory effect" on the CLDH returning to LDH was studied by the hydration reaction. It is shown that the "memory effect" is not complete, and the decreases of the Mg/Al molar ratio of LDH and the crystallite size due to the increase of the hydration reaction time result in the drop of the activity and the selectivity.Keyworcds Ethanol, Propylene oxide, Calcined layered double hydroxide, "Memory effect", Hydration

  8. Influence of calcination atmosphere on photocatalytic reactivity of K2La2Ti3O10 for water splitting

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The layered perovskite type oxide K2La2Ti3O10 powders were prepared under air, Ar and H2 calcination atmospheres by sol-gel method and characterized by X-ray diffractometry, UV-Vis diffuse reflectance and X-ray photoelectron spectroscopy. The influence of the calcination atmosphere on the photocatalytic reactivity of K2La2Ti3O10 for hydrogen production was investigated.The photocatalytic reactivity of K2La2Ti3O10 prepared under air, Ar and H2 atmospheres was compared with that prepared under ultraviolet and visible light radiation using I- as electronic donor. The results show that K2La2Ti3O10 prepared under Ar and H2atmospheres has higher photocatalytic activity for hydrogen production than that prepared under air atmosphere. The hydrogen

  9. Tailoring the Microstructure of a Solid Oxide Fuel Cell Anode Support by Calcination and Milling of YSZ.

    Science.gov (United States)

    Hanifi, Amir Reza; Laguna-Bercero, Miguel A; Sandhu, Navjot Kaur; Etsell, Thomas H; Sarkar, Partha

    2016-01-01

    In this study, the effects of calcination and milling of 8YSZ (8 mol% yttria stabilized zirconia) used in the nickel-YSZ anode on the performance of anode supported tubular fuel cells were investigated. For this purpose, two different types of cells were prepared based on a Ni-YSZ/YSZ/Nd2NiO4+δ-YSZ configuration. For the anode preparation, a suspension was prepared by mixing NiO and YSZ in a ratio of 65:35 wt% (Ni:YSZ 50:50 vol.%) with 30 vol.% graphite as the pore former. As received Tosoh YSZ or its calcined form (heated at 1500 °C for 3 hours) was used in the anode support as the YSZ source. Electrochemical results showed that optimization of the fuel electrode microstructure is essential for the optimal distribution of gas within the support of the cell, especially under electrolysis operation where the performance for an optimized cell (calcined YSZ) was enhanced by a factor of two. In comparison with a standard cell (containing as received YSZ), at 1.5 V and 800 °C the measured current density was -1380 mA cm(-2) and -690 mA cm(-2) for the cells containing calcined and as received YSZ, respectively. The present study suggests that the anode porosity for improved cell performance under SOEC is more critical than SOFC mode due to more complex gas diffusion under electrolysis mode where large amount of steam needs to be transfered into the cell. PMID:27270152

  10. Structure and luminescence behaviour of as-synthesized, calcined, and restored MgAlEu-LDH with high crystallinity.

    Science.gov (United States)

    Zhao, Yushuang; Li, Ji-Guang; Fang, Fang; Chu, Nankai; Ma, Hui; Yang, Xiaojing

    2012-10-21

    Highly crystalline Eu(3+)-incorporated MgAl layered double hydroxides (LDHs) were synthesized by the homogeneous precipitation method. For the crystals as-prepared, after their calcination from 200-1000 °C, and, further, after restoration in a Na(2)CO(3) solution, the structural and luminescent changes were investigated for the first time. Eu(3+) ions with a coordination number of, probably, 8, were incorporated into the hydrotalcite layer, which led to a basal spacing (d(basal)) increase, microstrain formation, and crystalline morphology imperfections, while retaining the original lattice symmetry, R3[combining macron]m. In the deconstruction process due to calcination, the Eu(3+) ions restrained the formation of the spinel phase from the layered double oxide (LDO), but did not significantly change the memory effect, by which LDOs can convert to LDHs during the hydration process. For the reversible phase transformation between LDH and LDO, the morphology observation revealed that, in addition to the formation of pores on the surface, nano-slabs were formed, especially for the restored crystals. A layered phase with a d(basal) of 5.8 Å, due to bridging bidentate carbonates with the hydrotalcite layer, was formed in the calcination process at low temperature (300 °C) before the formation of LDO, but could not be restored to a large spacing. Typical (5)D(0) → (7)F(J) (J = 0-4) transitions of Eu(3+) at 579, 593, 615, 653, and 698 nm were observed in the photoluminescence spectra and the intensity of the dominating 615 nm band decreased with the LDH deconstruction and the formation of free water, and then increased with the formation of LDOs in the calcination process, and vice versa in the reconstruction process. The Eu(3+) ions had a probable 9- or 10-coordination mode in addition to the probable 8-coordination mode as the spinel phase appeared. PMID:22930336

  11. Tailoring the Microstructure of a Solid Oxide Fuel Cell Anode Support by Calcination and Milling of YSZ

    Science.gov (United States)

    Hanifi, Amir Reza; Laguna-Bercero, Miguel A.; Sandhu, Navjot Kaur; Etsell, Thomas H.; Sarkar, Partha

    2016-06-01

    In this study, the effects of calcination and milling of 8YSZ (8 mol% yttria stabilized zirconia) used in the nickel-YSZ anode on the performance of anode supported tubular fuel cells were investigated. For this purpose, two different types of cells were prepared based on a Ni-YSZ/YSZ/Nd2NiO4+δ-YSZ configuration. For the anode preparation, a suspension was prepared by mixing NiO and YSZ in a ratio of 65:35 wt% (Ni:YSZ 50:50 vol.%) with 30 vol.% graphite as the pore former. As received Tosoh YSZ or its calcined form (heated at 1500 °C for 3 hours) was used in the anode support as the YSZ source. Electrochemical results showed that optimization of the fuel electrode microstructure is essential for the optimal distribution of gas within the support of the cell, especially under electrolysis operation where the performance for an optimized cell (calcined YSZ) was enhanced by a factor of two. In comparison with a standard cell (containing as received YSZ), at 1.5 V and 800 °C the measured current density was ‑1380 mA cm‑2 and ‑690 mA cm‑2 for the cells containing calcined and as received YSZ, respectively. The present study suggests that the anode porosity for improved cell performance under SOEC is more critical than SOFC mode due to more complex gas diffusion under electrolysis mode where large amount of steam needs to be transfered into the cell.

  12. Calcined Eggshell Waste for Mitigating Soil Antibiotic-Resistant Bacteria/Antibiotic Resistance Gene Dissemination and Accumulation in Bell Pepper.

    Science.gov (United States)

    Ye, Mao; Sun, Mingming; Feng, Yanfang; Li, Xu; Schwab, Arthur P; Wan, Jinzhong; Liu, Manqiang; Tian, Da; Liu, Kuan; Wu, Jun; Jiang, Xin

    2016-07-13

    The combined accumulation of antibiotics, heavy metals, antibiotic-resistant bacteria (ARB)/antibiotic resistance genes (ARGs) in vegetables has become a new threat to human health. This is the first study to investigate the feasibility of calcined eggshells modified by aluminum sulfate as novel agricultural wastes to impede mixed contaminants from transferring to bell pepper (Capsicum annuum L.). In this work, calcined eggshell amendment mitigated mixed pollutant accumulation in bell pepper significantly, enhanced the dissipation of soil tetracycline, sulfadiazine, roxithromycin, and chloramphenicol, decreased the water-soluble fractions of antibiotics, and declined the diversity of ARB/ARGs inside the vegetable. Moreover, quantitative polymerase chain reaction analysis detected that ARG levels in the bell pepper fruits significantly decreased to 10(-10) copies/16S copies, indicating limited risk of ARGs transferring along the food chain. Furthermore, the restoration of soil microbial biological function suggests that calcined eggshell is an environmentally friendly amendment to control the dissemination of soil ARB/ARGs in the soil-vegetable system. PMID:27333280

  13. SMALL-SCALE TESTING OF PLUTONIUM (IV) OXALATE PRECIPITATION AND CALCINATION TO PLUTONIUM OXIDE TO SUPPORT THE MOX FEED MISSION

    Energy Technology Data Exchange (ETDEWEB)

    Crowder, M.; Pierce, R.; Scogin, J.; Daniel, G.; King, W.

    2012-06-25

    The H-Canyon facility will be used to dissolve Pu metal for subsequent purification and conversion to plutonium dioxide (PuO{sub 2}) using Phase II of HB-Line. To support the new mission, SRNL conducted a series of experiments to produce calcined plutonium (Pu) oxide and measure the physical properties and water adsorption of that material. This data will help define the process operating conditions and material handling steps for HB-Line. An anion exchange column experiment produced 1.4 L of a purified 52.6 g/L Pu solution. Over the next nine weeks, seven Pu(IV) oxalate precipitations were performed using the same stock Pu solution, with precipitator feed acidities ranging from 0.77 M to 3.0 M nitric acid and digestion times ranging from 5 to 30 minutes. Analysis of precipitator filtrate solutions showed Pu losses below 1% for all precipitations. The four larger precipitation batches matched the target oxalic acid addition time of 44 minutes within 4 minutes. The three smaller precipitation batches focused on evaluation of digestion time and the oxalic acid addition step ranged from 25-34 minutes because of pump limitations in the low flow range. Following the precipitations, 22 calcinations were performed in the range of 610-690 C, with the largest number of samples calcined at either 650 or 635 C. Characterization of the resulting PuO{sub 2} batches showed specific surface areas in the range of 5-14 m{sup 2}/g, with 16 of the 22 samples in the range of 5-10 m2/g. For samples analyzed with typical handling (exposed to ambient air for 15-45 minutes with relative humidities of 20-55%), the moisture content as measured by Mass Spectrometry ranged from 0.15 to 0.45 wt % and the total mass loss at 1000 C, as measured by TGA, ranged from 0.21 to 0.58 wt %. For the samples calcined between 635 and 650 C, the moisture content without extended exposure ranged from 0.20 to 0.38 wt %, and the TGA mass loss ranged from 0.26 to 0.46 wt %. Of these latter samples, the samples

  14. Synthesis of type A zeolite from calcinated kaolin; Sintese de zeolita tipo A a partir de caulim calcinado

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, E.C.; Neves, R.F.; Souza, J.A.S. [Universidade Federal do Para (PPEQ/UFPA), Abaetetuba, PA (Brazil). Instituto de Engenharia Quimica. Programa de Pos-Graduacao; Moraes, C.G.; Macedo, E.N., E-mail: mersone7@yahoo.com.br [Universidade Federal do Para (PRODERNA/UFPA), Abaetetuba, PA (Brazil). Programa de Pos-Graduacao em Engenharia de Recursos Naturais da Amazonia

    2011-07-01

    The mineral production has caused great concern in environmental and industrial scenario due to the effects caused to the environment. The industries of processing kaolin for paper are important economically for the state of Para, but produce huge quantities of tailings, which depend on large areas to be stocked. This material is rich in silico-aluminates can be recycled and used as raw material for other industries. The objective is to synthesize zeolite A at different temperatures of calcination and synthesis. The starting materials and synthesis of zeolite A have been identified and characterized through analysis of X-ray diffraction (DRX) and scanning electron microscopy (MEV). The synthesis process of zeolite A, using as source of silica and the aluminum metakaolin, which was calcined at temperatures of 700 ° C and 800 ° C for 2 hours of landing in a burning furnace type muffle. Observed in relation to the calcination of kaolin as the main phase, the metakaolin. This is just a removal of water from its structure, so we opted for the lower temperature, less energy consumption. The synthesis process of zeolite A, produced good results for the formation of zeolites type A, which were characterized with high purities. (author)

  15. 均质铝矾土煅烧技术的研究%Study on calcining technology for homogeneous bauxite

    Institute of Scientific and Technical Information of China (English)

    谭莹

    2011-01-01

    A simulation experiment study is carried out for homogenous bauxite in tunnel kiln. The ex- periment result shows that the optimal calcining schedule for homogenous bauxite is 1 550℃, 5h. Here the bulk density reaches 3.45g.cm^-3 and the internal microstructure of the bauxite reaches optimal state. Meanwhile the quality index of the specimen is better than that of calcined bauxite QA1-88 obviously. Key words: Homogeneous bauxite ; Calcining temperature ; Holding time ; Quality index%在隧道窑中对均质铝矾土进行了模拟实验研究,结果表明:均质铝矾土的最佳煅烧制度为1550℃、5h,体积密度可达到3.45g·cm^-3,且铝矾土内部微观结构达到最佳状态。同时样品的质量指标明显优于优质铝矾土熟料QA1—88指标。

  16. Mesoporous Titania Powders: The Role of Precursors, Ligand Addition and Calcination Rate on Their Morphology, Crystalline Structure and Photocatalytic Activity

    Directory of Open Access Journals (Sweden)

    Elisabetta Masolo

    2014-07-01

    Full Text Available We evaluate the influence of the use of different titania precursors, calcination rate, and ligand addition on the morphology, texture and phase content of synthesized mesoporous titania samples, parameters which, in turn, can play a key role in titania photocatalytic performances. The powders, obtained through the evaporation-induced self-assembly method, are characterized by means of ex situ X-Ray Powder Diffraction (XRPD measurements, N2 physisorption isotherms and transmission electron microscopy. The precursors are selected basing on two different approaches: the acid-base pair, using TiCl4 and Ti(OBu4, and a more classic route with Ti(OiPr4 and HCl. For both precursors, different specimens were prepared by resorting to different calcination rates and with and without the addition of acetylacetone, that creates coordinated species with lower hydrolysis rates, and with different calcination rates. Each sample was employed as photoanode and tested in the water splitting reaction by recording I-V curves and comparing the results with commercial P25 powders. The complex data framework suggests that a narrow pore size distribution, due to the use of acetylacetone, plays a major role in the photoactivity, leading to a current density value higher than that of P25.

  17. Process for capturing CO2 arising from the calcination of the CaCO3 used in cement manufacture.

    Science.gov (United States)

    Rodríguez, N; Alonso, M; Grasa, G; Abanades, J Carlos

    2008-09-15

    This paper outlines a new CaCO3 calcination method for producing a stream of CO2 (suitable for permanent geological storage after purification and compression). The process is based on the use of very hot CaO particles (T >1000 degrees C) to transfer heat from a circulating fluidized bed combustor (CFBC) to a calciner (fluidized with CO2 and/or steam). Since the fluidized bed combustor and calciner have separate atmospheres, the CO2 resulting from the decomposition of CaCO3 can be captured, while the CO2 generated in the combustion of the fuel in air is emitted to the atmosphere. We demonstrate that with this system it is possible to reduce the CO2 emissions of a cement plant by around 60%. Furthermore, since the key pieces of equipment are similar to the commercial CFBCs used in power generation plants, it is possible to establish the additional investment required for the system and to estimate the cost per ton of CO2 avoided for this process to be about 19 $/tCO2 avoided. PMID:18853819

  18. An interdisciplinary physical-chemical approach for characterization of arsenic in a calciner residue dump in Cornwall (UK)

    Energy Technology Data Exchange (ETDEWEB)

    Teun van Elteren, Johannes [National Institute of Chemistry (Kiribati), Hajdrihova 19, SI-1001, Ljubljana (Slovenia)]. E-mail: elteren@ki.si; Slejkovec, Zdenka [Jozef Stefan Institute, Jamova 39 (IJS), SI-1000 Ljubljana (Slovenia); Arcon, Iztok [Jozef Stefan Institute, Jamova 39 (IJS), SI-1000 Ljubljana (Slovenia); Nova Gorica Polytechnic (PNG), Vipavska 13, SI-5000 Nova Gorica (Slovenia); Glass, Hylke-Jan [University of Exeter in Cornwall (UEC), Tremough Campus, TR10 9EZ Penryn, Cornwall (United Kingdom)

    2006-02-15

    During the later stages of hard-rock mining in Cornwall, UK, widespread processing and refining of arsenic in purpose-built calciners resulted in severe, localized contamination of soils with arsenic. Several physical-chemical techniques were applied to characterize arsenic in a calciner residue dump: X-ray powder diffraction (XRD), sequential extraction combined with hyphenated speciation methods, and X-ray absorption spectroscopic (XAS) methods such as XANES (X-ray absorption near-edge structure) and EXAFS (extended X-ray absorption fine structure). Arsenic was predominantly present in pentavalent form, bound to amorphous or poorly-crystalline hydrous oxides of Fe (probably {alpha}-hematite). A small amount of a non-classified crystalline iron arsenate phase was found, viz. Fe{sub 2}(As(AsO{sub 4}){sub 3}). There was also evidence for the presence of some arsenate bound to quartz ({alpha}-SiO{sub 2}). The overall results make us believe that the normally assumed relative safety, from a mobility point of view, is questionable since only a small fraction of arsenic is found in a crystalline iron arsenate form. - Arsenic in calciner residue dumps is present as arsenate in crystalline (Fe{sub 2}(As(AsO{sub 4}){sub 3})) and amorphous or poorly-crystalline (bound to hematite and quartz) structures.

  19. Process for capturing CO2 arising from the calcination of the CaCO3 used in cement manufacture.

    Science.gov (United States)

    Rodríguez, N; Alonso, M; Grasa, G; Abanades, J Carlos

    2008-09-15

    This paper outlines a new CaCO3 calcination method for producing a stream of CO2 (suitable for permanent geological storage after purification and compression). The process is based on the use of very hot CaO particles (T >1000 degrees C) to transfer heat from a circulating fluidized bed combustor (CFBC) to a calciner (fluidized with CO2 and/or steam). Since the fluidized bed combustor and calciner have separate atmospheres, the CO2 resulting from the decomposition of CaCO3 can be captured, while the CO2 generated in the combustion of the fuel in air is emitted to the atmosphere. We demonstrate that with this system it is possible to reduce the CO2 emissions of a cement plant by around 60%. Furthermore, since the key pieces of equipment are similar to the commercial CFBCs used in power generation plants, it is possible to establish the additional investment required for the system and to estimate the cost per ton of CO2 avoided for this process to be about 19 $/tCO2 avoided.

  20. Performance of Cobalt-Based Fischer-Tropsch Synthesis Catalysts Using Dielectric-Barrier Discharge Plasma as an Alternative to Thermal Calcination

    Science.gov (United States)

    Bai, Suli; Huang, Chengdu; Lv, Jing; Li, Zhenhua

    2012-01-01

    Co-based catalysts were prepared by using dielectric-barrier discharge (DBD) plasma as an alternative method to conventional thermal calcination. The characterization results of N2-physisorption, temperature programmed reduction (TPR), transmission electron microscope (TEM), and X-ray diffraction (XRD) indicated that the catalysts prepared by DBD plasma had a higher specific surface area, lower reduction temperature, smaller particle size and higher cobalt dispersion as compared to calcined catalysts. The DBD plasma method can prevent the sintering and aggregation of active particles on the support due to the decreased treatment time (0.5 h) at lower temperature compared to the longer thermal calcination at higher temperature (at 500° C for 5 h). As a result, the catalytic performance of the Fischer-Tropsch synthesis on DBD plasma treated Co/SiO2 catalyst showed an enhanced activity, C5+ selectivity and catalytic stability as compared to the conventional thermal calcined Co/SiO2 catalyst.

  1. Chloride adsorption by calcined layered double hydroxides in hardened Portland cement paste

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Seyoon [School of Engineering, Kings College, University of Aberdeen, Aberdeen AB24 3UE (United Kingdom); Moon, Juhyuk, E-mail: juhyuk.moon@stonybrook.edu [Civil Engineering Program, Department of Mechanical Engineering, State University of New York at Stony Brook, New York 11794 (United States); Bae, Sungchul [Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720 (United States); Duan, Xiaonan [Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14853 (United States); Giannelis, Emmanuel P. [Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14853 (United States); Center for Refining and Petrochemicals, The Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Monteiro, Paulo M. [Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720 (United States)

    2014-06-01

    This study investigated the feasibility of using calcined layered double hydroxides (CLDHs) to prevent chloride-induced deterioration in reinforced concrete. CLDHs not only adsorbed chloride ions in aqueous solution with a memory effect but also had a much higher binding capacity than the original layered double hydroxides (LDHs) in the cement matrix. We investigated this adsorption in hardened cement paste in batch cultures to determine adsorption isotherms. The measured and theoretical binding capacities (153 mg g{sup −1} and 257 mg g{sup −1}, respectively) of the CLDHs were comparable to the theoretical capacity of Friedel's salt (2 mol mol{sup −1} or 121 mg g{sup −1}), which belongs to the LDH family among cementitious phases. We simulated chloride adsorption by CLDHs through the cement matrix using the Fickian model and compared the simulation result to the X-ray fluorescence (XRF) chlorine map. Based on our results, it is proposed that the adsorption process is governed by the chloride transport through the cement matrix; this process differs from that in an aqueous solution. X-ray diffraction (XRD) analysis showed that the CLDH rebuilds the layered structure in a cementitious environment, thereby demonstrating the feasibility of applying CLDHs to the cement and concrete industries. - Highlights: • We examine the adsorption equilibrium and kinetics of CLDH in the hydrated cement. • CLDH capacity to bind chloride ions in the hydrated cement paste is determined. • We model chloride adsorption by CLDH through the cement matrix. • CLDH reforms the layered structure with ion adsorption in the cement matrix.

  2. Behavior of radioactive iodine and technetium in the spray calcination of high-level waste

    International Nuclear Information System (INIS)

    The Remote Laboratory-Scale Waste Treatment Facility (RLSWTF) was designed and built as a part of the High-Level Waste Immobilization Program (now the High-Level Waste Process Development Program) at the Pacific Northwest Laboratory. In this facility, which is installed in a radiochemical cell, small volumes of radioactive liquid wastes can be solidified, the process off gas can be analyzed, and the methods for decontaminating this off gas can be tested. Initial operations were completed with nonradioactive, simulated waste solutions (Knox, Siemens and Berger 1981). The first radioactive operations in this facility were performed with a simulated, commercial waste composition containing tracer levels of 99Tc and 131I. This report describes the facility and test operations and presents the results of the behavior of 131I and 99Tc during solidification of radioactive liquid wastes. During the spray calcination of commercial high-level liquid waste spiked with 99Tc and 131I, there was a 0.3 wt% loss of particulates, a 0.15 wt% loss of 99Tc and a 31 wt% loss of 131I past the sintered-metal filters. These filters and a venturi scrubber were very efficient in removing particulates and 99Tc from the off-gas stream. Liquid scrubbers were not efficient in removing 131I, as 25% of the total lost went to the building off-gas system. Therefore, solid adsorbents will be needed to remove iodine. For all future RLSWTF operations where iodine is present, a silver zeolite adsorber will be used

  3. Chloride adsorption by calcined layered double hydroxides in hardened Portland cement paste

    International Nuclear Information System (INIS)

    This study investigated the feasibility of using calcined layered double hydroxides (CLDHs) to prevent chloride-induced deterioration in reinforced concrete. CLDHs not only adsorbed chloride ions in aqueous solution with a memory effect but also had a much higher binding capacity than the original layered double hydroxides (LDHs) in the cement matrix. We investigated this adsorption in hardened cement paste in batch cultures to determine adsorption isotherms. The measured and theoretical binding capacities (153 mg g−1 and 257 mg g−1, respectively) of the CLDHs were comparable to the theoretical capacity of Friedel's salt (2 mol mol−1 or 121 mg g−1), which belongs to the LDH family among cementitious phases. We simulated chloride adsorption by CLDHs through the cement matrix using the Fickian model and compared the simulation result to the X-ray fluorescence (XRF) chlorine map. Based on our results, it is proposed that the adsorption process is governed by the chloride transport through the cement matrix; this process differs from that in an aqueous solution. X-ray diffraction (XRD) analysis showed that the CLDH rebuilds the layered structure in a cementitious environment, thereby demonstrating the feasibility of applying CLDHs to the cement and concrete industries. - Highlights: • We examine the adsorption equilibrium and kinetics of CLDH in the hydrated cement. • CLDH capacity to bind chloride ions in the hydrated cement paste is determined. • We model chloride adsorption by CLDH through the cement matrix. • CLDH reforms the layered structure with ion adsorption in the cement matrix

  4. Extended Development Work to Validate a HLW Calcine Waste Form via INL's Cold Crucible Induction Melter

    Energy Technology Data Exchange (ETDEWEB)

    James A. King; Vince Maio

    2011-09-01

    To accomplish calcine treatment objectives, the Idaho Clean-up Project contractor, CWI, has chosen to immobilize the calcine in a glass-ceramic via the use of a Hot-Isostatic-Press (HIP); a treatment selection formally documented in a 2010 Record of Decision (ROD). Even though the HIP process may prove suitable for the calcine as specified in the ROD and validated in a number of past value engineering sessions, DOE is evaluating back-up treatment methods for the calcine as a result of the technical, schedule, and cost risk associated with the HIPing process. Consequently DOE HQ has requested DOE ID to make INL's bench-scale cold-crucible induction melter (CCIM) available for investigating its viability as a process alternate to calcine treatment. The waste form is the key component of immobilization of radioactive waste. Providing a solid, stable, and durable material that can be easily be stored is the rationale for immobilization of radioactive waste material in glass, ceramic, or glass-ceramics. Ceramic waste forms offer an alternative to traditional borosilicate glass waste forms. Ceramics can usually accommodate higher waste loadings than borosilicate glass, leading to smaller intermediate and long-term storage facilities. Many ceramic phases are known to possess superior chemical durability as compared to borosilicate glass. However, ceramics are generally multiphase systems containing many minor phase that make characterization and prediction of performance within a repository challenging. Additionally, the technologies employed in ceramic manufacture are typically more complex and expensive. Thus, many have proposed using glass-ceramics as compromise between in the more inexpensive, easier to characterize glass waste forms and the more durable ceramic waste forms. Glass-ceramics have several advantages over traditional borosilicate glasses as a waste form. Borosilicate glasses can inadvertently devitrify, leading to a less durable product that could

  5. The Influence of Calcined Clay Pozzolan, Low-Cao Steel Slag and Granite Dust On the Alkali-Silica Reaction in Concrete

    Directory of Open Access Journals (Sweden)

    James Sarfo-Ansah

    2015-08-01

    Full Text Available The influence of low CaO steel slag, calcined clay and granite dust on the alkali-silica reaction was investigated over a period of 35 days under accelerated curing conditions. The mineral admixtures were used to replace varying portions of high alkali Portland limestone cement up to an admixture content of 25% in order to study their effect on the alkali-silica reaction (ASR. Portland limestone cement used for the study had a total Na2Oeq of 4.32. XRD analysis of hydrated mortar bar samples confirmed the formation of an expansive sodium silica gel in the reference Portland cement mortar bar as the agent responsible for ASR. Stable calcium silicates were formed in the mortar bars containing calcined clay in increasing quantities whilst the presence of the sodium silicate gel decreased.The occurrence of these stable silicates in hydrated samples containing steel slag and granite dust was however minimal, compared to calcined clay cement mortars. The highest expansion was recorded for granite dust mortar bars, reaching a maximum of 25.98% at 35 days. Mortar-bar expansion decreased as calcined clay content in the cement increased;mortar bars with 25% calcined clay were the least expansive recording expansion less than 0.1% at all test ages. Whilst the expansion was reduced by between 42.5% and 107.8% at 14 days with increasing calcined clay content, expansion rather increased between 36.8% and 169.5% at 14 days with increasing granite dust content.Steel slag mortar bars experienced reduction in 14 days expansion between 14.3% - 46.2%.The study confirms that steel slag and calcined clay pozzolan have greater influence on ASR in mortar bars than granite dust and shows that calcined clay and low CaO steel slag could be considered as remedial admixtures for ASR at replacement levels of 25% and 15% respectively.

  6. Catalyst used in 1,2-epoxyalkane preparation is obtained by heating tetraalkyl ammonium salts, tetraalkyl siloxanes and amines, calcining and treating with a tetraalkoxy compound

    DEFF Research Database (Denmark)

    2001-01-01

    NOVELTY - The catalyst, used in 1,2-epoxyalkane preparation, is obtained by heat treating an aqueous composition comprising tetraalkyl ammonium salts, tetraalkyl siloxanes and amines, removing the template by calcining and treating with a tetraalkoxy compound......NOVELTY - The catalyst, used in 1,2-epoxyalkane preparation, is obtained by heat treating an aqueous composition comprising tetraalkyl ammonium salts, tetraalkyl siloxanes and amines, removing the template by calcining and treating with a tetraalkoxy compound...

  7. Preparation and Characterization of Au/Pd Modified-TiO2 Photocatalysts for Phenol and Toluene Degradation under Visible Light—The Effect of Calcination Temperature

    Directory of Open Access Journals (Sweden)

    Anna Cybula

    2014-01-01

    Full Text Available Rutile loaded with Au/Pd nanoparticles was prepared using a water-in-oil microemulsion system of water/AOT/cyclohexane followed by calcination. The effect of calcination temperature (from 350 to 700°C on the structure of Au/Pd nanoparticles deposited at rutile matrix and the photocatalytic properties of Au/Pd-TiO2 was investigated in two model reactions (toluene degradation in gas phase and phenol degradation in aqueous phase. Toluene was irradiated over Au/Pd-TiO2 using light emitting diodes (LEDs, λmax⁡ = 415 nm. The sample 0.5 mol% Pd/TiO2 exhibited the highest activity under visible light irradiation in gas and aqueous phase reaction among all photocatalysts calcined at 350°C, while the sample modified only with gold nanoparticles showed the lowest activity. The Au/Pd-TiO2 sample calcinated at 350°C possesses the highest photocatalytic activity when degrading phenol under visible light, which is 14 times higher than that of the one calcinated at 450°C. It was observed that increasing temperature from 350 to 700°C during calcination step caused segregation of metals and finally resulted in photoactivity drop.

  8. SMALL-SCALE TESTING OF PLUTONIUM (IV) OXALATE PRECIPITATION AND CALCINATION TO PLUTONIUM OXIDE TO SUPPORT THE MOX FEED MISSION

    Energy Technology Data Exchange (ETDEWEB)

    Crowder, M.; Pierce, R.; Scogin, J.; Daniel, G.; King, W.

    2012-06-25

    The H-Canyon facility will be used to dissolve Pu metal for subsequent purification and conversion to plutonium dioxide (PuO{sub 2}) using Phase II of HB-Line. To support the new mission, SRNL conducted a series of experiments to produce calcined plutonium (Pu) oxide and measure the physical properties and water adsorption of that material. This data will help define the process operating conditions and material handling steps for HB-Line. An anion exchange column experiment produced 1.4 L of a purified 52.6 g/L Pu solution. Over the next nine weeks, seven Pu(IV) oxalate precipitations were performed using the same stock Pu solution, with precipitator feed acidities ranging from 0.77 M to 3.0 M nitric acid and digestion times ranging from 5 to 30 minutes. Analysis of precipitator filtrate solutions showed Pu losses below 1% for all precipitations. The four larger precipitation batches matched the target oxalic acid addition time of 44 minutes within 4 minutes. The three smaller precipitation batches focused on evaluation of digestion time and the oxalic acid addition step ranged from 25-34 minutes because of pump limitations in the low flow range. Following the precipitations, 22 calcinations were performed in the range of 610-690 C, with the largest number of samples calcined at either 650 or 635 C. Characterization of the resulting PuO{sub 2} batches showed specific surface areas in the range of 5-14 m{sup 2}/g, with 16 of the 22 samples in the range of 5-10 m2/g. For samples analyzed with typical handling (exposed to ambient air for 15-45 minutes with relative humidities of 20-55%), the moisture content as measured by Mass Spectrometry ranged from 0.15 to 0.45 wt % and the total mass loss at 1000 C, as measured by TGA, ranged from 0.21 to 0.58 wt %. For the samples calcined between 635 and 650 C, the moisture content without extended exposure ranged from 0.20 to 0.38 wt %, and the TGA mass loss ranged from 0.26 to 0.46 wt %. Of these latter samples, the samples

  9. Performance assessment of CO2 capture with calcination carbonation reaction process driven by coal and concentrated solar power

    International Nuclear Information System (INIS)

    Calcination carbonation reaction (CCR) process is regarded as a promising option for pulverized coal power plant to mitigate CO2 emission. In this paper, concentrated solar power (CSP) substitutes for coal to supply part of the calcination energy in order to reduce the fossil fuel consumption associated with the calciner. A CCR process driven by coal and CSP is examined from the perspective of energy efficiency. This paper focuses on the parameters of heat recovery efficiency, CSP capacity, compression energy, air separation energy and recycled energy to determine the contribution of each to the overall energy penalty. In addition, the effects of heat recovery efficiency, CSP capacity, purge percentage and CO2 capture efficiency on the co-driven case are analyzed through a sensitivity analysis. The results indicate that the thermal efficiency of integrating CCR co-driven process into an ultra-supercritical 1019 MW power plant is 35.37%, which means that the overall efficiency penalty is 9.63 percentage points. Moreover, the co-driven case reduces the fossil fuel consumption and the mass flow rate of fresh sorbent and circulation solids compared with coal-driven case. Increasing heat recovery efficiency and CSP efficiency can improve the co-driven case performance. - Highlights: • We examine a CCR process driven by coal and concentrated solar power simultaneously. • The contributors to the overall energy penalty are quantitatively identified. • Obvious coal-saving effect has been found in the co-driven system. • A sensitivity analysis is conducted to find the impact of key parameters

  10. Rheology and zeta potential of cement pastes containing calcined silt and ground granulated blast-furnace slag

    OpenAIRE

    B. Safi; A. Benmounah; Saidi, M.

    2011-01-01

    This study aimed to analyse the re-use of dam silt as a supplementary binder for self-compacting concrete (SCC). When burnt, silt becomes more reactive because the kaolin it contains is converted into metakaolin. Portland cement, calcined or burnt silt and ground granulated blast furnace slag were used in this research. Cement pastes were prepared with blends containing two or three of these materials. The replacement ratio for burnt silt in both cases was 10 % and 20 % by cement weight and t...

  11. Precipitation and calcination synthesis methods forming nano-sized platinum catalytic particles for methanol and hydrogen oxidation

    Science.gov (United States)

    Naidoo, S.; Naidoo, Q.; Musil, E.; Linkov, V.; Vaivars, G.

    2013-03-01

    Under varying experimental conditions of calcination and precipitation reactions, different particle sizes and levels of platinum on carbon supported (Pt/C) catalysts were obtained. Rapid precipitation following a chemical reaction ensured formation of nano-sized catalytic particles using super-saturated concentrations under controlled conditions was a significant contribution in understanding the synthesis process and how it relates to an increased number of catalytic reaction sites ultimately providing superior electrochemical (EC) activity. These conditions influenced nucleation and growth rates of the catalytic particles. The super-saturation concentrations of the reactants in the reaction vessel played a direct role in producing the desired morphology of the crystallites.

  12. Arsenic removal from aqueous solutions using Fe3O4-HBC composite: effect of calcination on adsorbents performance.

    Directory of Open Access Journals (Sweden)

    Shams Ali Baig

    Full Text Available The presence of elevated concentration of arsenic in water sources is considered to be health hazard globally. Calcination process is known to change the surface efficacy of the adsorbent. In current study, five adsorbent composites: uncalcined and calcined Fe3O4-HBC prepared at different temperatures (400°C and 1000°C and environment (air and nitrogen were investigated for the adsorptive removal of As(V and As(III from aqueous solutions determining the influence of solution's pH, contact time, temperature, arsenic concentration and phosphate anions. Characterizations from FTIR, XRD, HT-XRD, BET and SEM analyses revealed that the Fe3O4-HBC composite at higher calcination temperature under nitrogen formed a new product (fayalite, Fe2SiO4 via phase transformation. In aqueous medium, ligand exchange between arsenic and the effective sorbent site ( = FeOOH was established from the release of hydroxyl group. Langmuir model suggested data of the five adsorbent composites follow the order: Fe3O4-HBC-1000°C(N2>Fe3O4-HBC (uncalcined>Fe3O4-HBC-400°C(N2>Fe3O4-HBC-400°C(air>Fe3O4-HBC-1000°C(air and the maximum As(V and As(III adsorption capacities were found to be about 3.35 mg g(-1 and 3.07 mg g(-1, respectively. The adsorption of As(V and As(III remained stable in a wider pH range (4-10 using Fe3O4-HBC-1000°C(N2. Additionally, adsorption data fitted well in pseudo-second-order (R2>0.99 rather than pseudo-first-order kinetics model. The adsorption of As(V and As(III onto adsorbent composites increase with increase in temperatures indicating that it is an endothermic process. Phosphate concentration (0.0l mM or higher strongly inhibited As(V and As(III removal through the mechanism of competitive adsorption. This study suggests that the selective calcination process could be useful to improve the adsorbent efficiency for enhanced arsenic removal from contaminated water.

  13. Electrochemical characterization for lithium vanadium phosphate with different calcination temperatures prepared by the sol–gel method

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yongchao [Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074 (China); Wang, Shengping, E-mail: spwang@cug.edu.cn [Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074 (China); Tao, Du; Dai, Yu [Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074 (China); Yu, Jingxian [ARC Centre of Excellence for Nanoscale BioPhotonics (CNBP), School of Chemistry and Physics, The University of Adelaide, Adelaide, SA 5005 (Australia)

    2015-09-15

    Li{sub 3}V{sub 2}(PO{sub 4}){sub 3}/C (LVP/C) composite materials were synthesized via a sol–gel method with oxalic acid as the chelating agent and polyethylene glycol (PEG) as the supplementary carbon source. The oxalic acid and PEG serve as double carbon sources. This study focused on the effect of different calcination temperatures on the electrochemical properties of Li{sub 3}V{sub 2}(PO{sub 4}){sub 3}. The diffraction peaks for all of the samples are well indexed to monoclinic Li{sub 3}V{sub 2}(PO{sub 4}){sub 3} with a P2{sub 1}/n space group. The TGA data indicate that the residual carbon content of LVP/C-700 is the highest (i.e., 2.31 wt.%), and as the calcination temperature increased, the residual carbon content of the material gradually decreased. SEM and TEM analyses indicated that the LVP particles that were calcined at 700 °C exhibit a uniform particle size distribution and the carbon coating exhibited a complete and orderly moderate thickness. The LVP/C-700 material exhibits the best electrochemical performance in the voltage range of 3.0 to 4.3 V and 0.1 C where the initial discharge capacity can reach 128.98 mAh g{sup −} {sup 1}. Even after 200 cycles, the discharge capacity was 119.31 mAh g{sup −} {sup 1}, and the capacity retention rate was 92.49%. - Highlights: • Li{sub 3}V{sub 2}(PO{sub 4}){sub 3}/C composite materials have been synthesized via a sol–gel method with double carbon sources. • The different calcination temperatures affect the grain growth and crystallinity of the Li{sub 3}V{sub 2}(PO{sub 4}){sub 3}/C materials. • The LVP/C-700 material exhibites the largest lithium ion diffusivity and electronic conductivity.

  14. Microwave Sintering of W-15Cu Ultrafine Composite Powder Prepared by Spray Drying & Calcining-continuous Reduction Technology

    Institute of Scientific and Technical Information of China (English)

    SHU Jingping; SHI Xiaoliang; WANG Shuwei; YANG Xingyong; ZHANG Qiaoxin; WANG Yufu

    2011-01-01

    The effects of microwave sintering and conventional H2 sintering on the microstructure and properties of W-l5Cu alloy using ultrafine W-15Cu composite powder fabricated by spray drying & calcining-continuous reduction technology were investigated. In comparison to the conventional H2 sintering processing, microwave sintefing to W-15Cu can be achieved at lower sintefing temperature and shorter sintering time. Furthermore, higher performances in microwave sintered compacts were obtained, but high microwave sintering temperature or long microwave sintering time could result in coarser microstructures.

  15. Effect of calcination temperature on physical parameters and photocatalytic activity of mesoporous titania spheres using chitosan/poly(vinyl alcohol) hydrogel beads as a template

    International Nuclear Information System (INIS)

    Highlights: • Mesoporous titania spheres were prepared using CS/PVA hydrogel beads as a template. • The titania spheres prepared was mesoporous structure. • The photocatalytic activity of the mesoporous titania spheres calcined at 500 °C was highest. - Abstract: Mesoporous titania spheres were prepared by modified sol–gel method using chitosan/poly(vinyl alcohol) hydrogel beads as a template. Effects of calcination temperature on physical parameters were investigated by X-ray diffraction (XRD), N2 adsorption–desorption, Fourier transform infrared (FT-IR) spectra, thermogravimetry and differential thermal analyses (TG-DTA), high-resolution transmission electron microscope (HRTEM) and scanning electron microscopy (SEM). The photocatalytic activity of mesoporous titania spheres prepared was also evaluated by photocatalytic degradation of phenol as a model molecule under UV irradiation. With increasing calcination temperature, average crystallite size and pore size increased. In contrast, Brunauer–Emmett–Teller (BET) specific surface areas, porosity and pore volumes steadily decreased. Results of characterization proved that prepared titania spheres with highly organized pores were mesoporous structure. The photocatalytic activity of mesoporous titania spheres calcined at 500 °C was more effective than those calcined at other temperatures, which were attributed to the porous structure, large BET surface area, crystalline, and smaller crystallite size. This work may provide new insights into the preparation of novel mesoporous titania spheres and further practical applications in the treatment of wastewater

  16. Technology Optimization Research of Calcining Asbestos Tailings with Ammonium Sulfate%石棉尾矿硫酸铵焙烧工艺优化研究

    Institute of Scientific and Technical Information of China (English)

    刘姝抒; 宋贝; 胡志波; 牛保军; 郑水林

    2015-01-01

    Asbestos tailings were preprocessed by ball-milling and calcining. This paper studied the influence of calcination temperature, calcination time and milling time on the roasting effect of asbestos tailings and ammonium sulfate. The result showed that the optimum conditions were that calcination temperature was 500℃, calcination time was 1 h, milling time was 18 min. Through being preprocessed, the leaching ratio of MgO was up from 70.03%to 95.29%.%对石棉尾矿进行预先煅烧和研磨处理,研究了煅烧温度、煅烧时间和研磨时间对石棉尾矿硫酸铵焙烧效果的影响,得到最佳的预处理条件:煅烧温度为500℃,煅烧时间为1 h,研磨时间为18 min。经过预处理后,石棉尾矿硫酸铵焙烧氧化镁溶出率从70.03%提高到95.29%。

  17. Influence of calcination temperature on the structure and morphology of HAp bioceramics; Influencia da temperatura de calcinacao na estrutura e morfologia de bioceramica de HAp

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, C.M.L.; Santos, P.T.A.; Rodrigues, P.A.; Costa, A.C.F.M. [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Unidade Academica de Engenharia de Materiais

    2012-07-01

    This study aimed to evaluate the influence of calcination temperature on the structure and morphology of samples of hydroxyapatite (HAp) synthesized by the wet method. For hydroxyapatite was used as precursor solutions of calcium hydroxide and phosphoric acid 1M solution of calcium hydroxide was stirred and heated to 80 ° C and then dropwise with a solution of phosphoric acid. After the liquid was evaporated without an oven at 110 ° C and sieved. The sample of PA as synthesized was submitted to calcination at 900 °C and 1100 °C / 2 hours. The samples as synthesized and after calcination were characterized by XRD, XRF, FTIR, SEM. The XRD showed the presence of phase hydroxyapatite for samples without calcining and both calcination temperatures studied. FTIR spectra showed bands group and PO{sub 4}{sup 3-}, CO{sub 3}{sup 2-}. Through the SEM micrograph, there is the formation of agglomerates in the form of porous flakes approximately spherical shape. (author)

  18. Effect of calcination temperatures on the electrochemical performances of nickel oxide/reduction graphene oxide (NiO/RGO) composites synthesized by hydrothermal method

    Science.gov (United States)

    Chen, Gang; Guan, Hongtao; Dong, Chengjun; Xiao, Xuechun; Wang, Yude

    2016-11-01

    A series of NiO/RGO composites based on NiO nanoparticles anchored on layered RGO surfaces were proposed by the same hydrothermal method combined with different calcination temperatures (250, 300, 400 and 500 °C). The effects of calcination temperatures on the capacitive behaviors have been discussed by investigating the components, morphologies, surface conditions of the NiO/RGO composites. The specific capacitance values of NiO/RGO composites calcined at 250, 300, 400 and 500 °C are 950, 553, 375 and 205 F/g at the current density of 1 A/g and the corresponding capacitance retention are 91.3%, 83.9%, 71.9% and 67.3% after 1000 cycles at the current density of 10 A/g. The results suggest the calcination temperature plays an important role in the electrochemical performances of NiO/RGO composites and the electrochemical performances were deteriorated with the increasing calcination temperatures.

  19. Influence of calcination temperature on selective catalytic reduction of NOx with NH3 over CeO2-ZrO2-WO3 catalyst

    Institute of Scientific and Technical Information of China (English)

    李军燕; 宋忠贤; 宁平; 张秋林; 刘昕; 李昊; 黄真真

    2015-01-01

    A series of CeO2-ZrO2-WO3 catalysts for the selective catalytic reduction (SCR) of NO with NH3 were prepared by hydro-thermal method. The influence of calcination temperature on the catalytic activity, microstructure, surface acidity and redox behavior of CeO2-ZrO2-WO3 catalyst was investigated using various characterization methods. It was found that the CeO2-ZrO2-WO3 catalyst calcined at 600 ºC showed the best catalytic performance and excellent N2 selectivity, and yielded more than 90% NO conversion in a wide temperature range of 250–500 ºC with a space velocity (GHSV) of 60000 h–1. As the calcination temperature was increased from 400 to 600 ºC, the NO conversion obviously increased, but decreased at higher calcination temperature. The results implied that the higher surface area, the strongest synergistic interaction, the superior redox property and the highly dispersed or amorphous WO3 species contributed to the excellent SCR activity of the CeO2-ZrO2-WO3 catalyst calcined at 600 ºC.

  20. Effect of calcination temperature on structure and performance of Ni/TiO2-SiO2 catalyst for CO2 reforming of methane

    Institute of Scientific and Technical Information of China (English)

    Sanbing Zhang; Jiankang Wang; Xiaolai Wang

    2008-01-01

    The influence of calcination temperature on the structure and catalytic behavior of Ni/TiO2-SiO2 catalyst, for CO2 reforming of methane to synthesis gas under atmospheric pressure, was investigated. The results showed that the Ni/TiO2-SiO2 catalyst calcined at 700 ℃ had high and stable activity while the catalysts calcined at 550 and 850 ℃ had low and un-stable activity. Depending on the calcination temperature, one, two, or three of the following Ni-contalning species, NiO,Ni2.44Ti0.72Si0.07O4, and NiTiO3 were identified by combining the temperature programmed reduction (TPR) and X-ray diffraction (XRD) results. Their reducibility decreased in the sequence: NiO>Ni2.44Ti0.72Si0.07O4>NiTiO3. It suggests that high and stable activities observed over the Ni/TiO2-SiO2 catalyst calcined at 700 ℃ were induced by the formation of Ni2.44Ti0.72Si0.07O4 and smaller NiO species crystallite size.

  1. Effect of calcination temperature on physical parameters and photocatalytic activity of mesoporous titania spheres using chitosan/poly(vinyl alcohol) hydrogel beads as a template

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, R. [Department of Environmental Engineering, Taizhou University, Taizhou 318000 (China); Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation, College of Life Science, Taizhou University, Taizhou 318000 (China); State Laboratory of Silica Materials and Department of Chemistry, Zhejiang University, Hangzhou 310027 (China); Zhu, H.-Y., E-mail: zhuhuayue@126.com [Department of Environmental Engineering, Taizhou University, Taizhou 318000 (China); Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation, College of Life Science, Taizhou University, Taizhou 318000 (China); Chen, H.-H. [State Laboratory of Silica Materials and Department of Chemistry, Zhejiang University, Hangzhou 310027 (China); Yao, J. [Department of Environmental Engineering, Taizhou University, Taizhou 318000 (China); Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation, College of Life Science, Taizhou University, Taizhou 318000 (China); Fu, Y.-Q. [Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation, College of Life Science, Taizhou University, Taizhou 318000 (China); Zhang, Z.-Y. [Department of Environmental Engineering, Taizhou University, Taizhou 318000 (China); Xu, Y.-M., E-mail: xuym@css.zju.edu.cn [State Laboratory of Silica Materials and Department of Chemistry, Zhejiang University, Hangzhou 310027 (China)

    2014-11-15

    Highlights: • Mesoporous titania spheres were prepared using CS/PVA hydrogel beads as a template. • The titania spheres prepared was mesoporous structure. • The photocatalytic activity of the mesoporous titania spheres calcined at 500 °C was highest. - Abstract: Mesoporous titania spheres were prepared by modified sol–gel method using chitosan/poly(vinyl alcohol) hydrogel beads as a template. Effects of calcination temperature on physical parameters were investigated by X-ray diffraction (XRD), N{sub 2} adsorption–desorption, Fourier transform infrared (FT-IR) spectra, thermogravimetry and differential thermal analyses (TG-DTA), high-resolution transmission electron microscope (HRTEM) and scanning electron microscopy (SEM). The photocatalytic activity of mesoporous titania spheres prepared was also evaluated by photocatalytic degradation of phenol as a model molecule under UV irradiation. With increasing calcination temperature, average crystallite size and pore size increased. In contrast, Brunauer–Emmett–Teller (BET) specific surface areas, porosity and pore volumes steadily decreased. Results of characterization proved that prepared titania spheres with highly organized pores were mesoporous structure. The photocatalytic activity of mesoporous titania spheres calcined at 500 °C was more effective than those calcined at other temperatures, which were attributed to the porous structure, large BET surface area, crystalline, and smaller crystallite size. This work may provide new insights into the preparation of novel mesoporous titania spheres and further practical applications in the treatment of wastewater.

  2. Oxidative desulfurization of benzothiophene and thiophene with WOx/ZrO2 catalysts: effect of calcination temperature of catalysts.

    Science.gov (United States)

    Hasan, Zubair; Jeon, Jaewoo; Jhung, Sung Hwa

    2012-02-29

    Oxidative desulfurization (ODS) of model fuel containing benzothiophene (BT) or thiophene (Th) has been carried out with WO(x)/ZrO2 catalyst, which was calcined at various temperatures. Based on the conversion of BT in the model fuel, it can be shown that the optimum calcination temperature of WOx/ZrO2 catalyst is around 700 °C. The most active catalyst is composed of tetragonal zirconia (ZrO2) with well dispersed polyoxotungstate species and it is necessary to minimize the contents of the crystalline WO3 and monoclinic ZrO2 for a high BT conversion. The oxidation rate was interpreted with the first-order kinetics, and it demonstrated the importance of electron density since the kinetic constant for BT was higher than that for Th even though the BT is larger than Th in size. A WOx/ZrO2 catalyst, treated suitably, can be used as a reusable active catalyst in the ODS. PMID:22245512

  3. Effects of Calcination Temperature and Acid-Base Properties on Mixed Potential Ammonia Sensors Modified by Metal Oxides

    Directory of Open Access Journals (Sweden)

    Kenichi Shimizu

    2011-02-01

    Full Text Available Mixed potential sensors were fabriated using yttria-stabilized zirconia (YSZ as a solid electrolyte and a mixture of Au and various metal oxides as a sensing electrode. The effects of calcination temperature ranging from 600 to 1,000 °C and acid-base properties of the metal oxides on the sensing properties were examined. The selective sensing of ammonia was achieved by modification of the sensing electrode using MoO3, Bi2O3 and V2O5, while the use of WO3, Nb2O5 and MgO was not effective. The melting points of the former group were below 820 °C, while those of the latter group were higher than 1,000 °C. Among the former group, the selective sensing of ammonia was strongly dependent on the calcination temperature, which was optimum around melting point of the corresponding metal oxides. The good spreading of the metal oxides on the electrode is suggested to be one of the important factors. In the former group, the relative response of ammonia to propene was in the order of MoO3 > Bi2O3 > V2O5, which agreed well with the acidity of the metal oxides. The importance of the acidic properties of metal oxides for ammonia sensing was clarified.

  4. Synthesis of anatase nanopowders by sol-gel method and influence of temperatures of calcination to their photocatalitic properties

    Directory of Open Access Journals (Sweden)

    Golubović A.

    2015-01-01

    Full Text Available The titanium dioxide (TiO2 nanopowders were produced by sol-gel technique from tetrabutyl titanate as a precursor, varying the temperature оf calcination (from 500 to 550°C with the step of 10 °C. XRPD results have shown that all synthesized nanopowders are dominantly in anatase phase. The analysis of the shift and linewidth of the most intensive anatase Eg Raman mode confirmed the XRPD results and added the presence of small amount of highly disordered brookite phase in all samples. The analysis of pore structure from nitrogen sorption experimental data described all samples as mesoporous, with mean pore diameters in the range of 1.5 and 4.5 nm. Nanopowder properties have been related to the photocatalytic activity, tested in degradation of the textile dye (C.I. Reactive Orange 16. The sample calcined at temperature of 510°C showed the best photocatalytic performance. [Projekat Ministarstva nauke Republike Srbije, br. III45018 i br. OI171032

  5. Effect of Calcinated Oyster Shell Powder on Growth, Yield, Spawn Run, and Primordial Formation of King Oyster Mushroom (Pleurotus Eryngii

    Directory of Open Access Journals (Sweden)

    Young-Chan Kim

    2011-03-01

    Full Text Available This study was conducted to evaluate the calcium (Ca absorption efficacy of king oyster mushroom (Pleurotus eryngii grown on sawdust medium supplemented with Ca-sources, including oyster shell powder, and to determine the efficacy of oyster shell powder as a calcium supplement on growth, yield, spawn run and primordial formation of P. eryngii. Optimum calcination of oyster shell powder was achieved at the temperature of 620.56 °C. A 1% supplementation of oyster shell powder in sawdust medium did not suppress the mycelial growth of P. eryngii. Also the supplementation of 2% calcinated oyster shell powder to sawdust medium potentially increased the calcium content up to a level of 315.7 ± 15.7 mg/100 g in the fruiting body of P. eryngii, without extension of duration of spawn run and the retardation of the days to primordial formation. These results suggest that the shellfish by-products, including oyster shell powder, can be utilized to develop calcium enriched king oyster mushrooms.

  6. Effect of Grain and Calcinations Kaolin Additives on Some Mechanical and Physical properties on Low DensityPolyethylene Composites

    Directory of Open Access Journals (Sweden)

    Zanaib Y. Shnean

    2008-01-01

    Full Text Available In this work, a composite material was prepared from Low-density polyethylene (LDPE with different weight percent of grain and calcinations kaolin at temperature of (850oC using single screw extruder and a mixing machine operated at a temperature between (190-200oC. Some of mechanical and physical properties such as tensile strength, tensile strength at break, Young modulus, and elongation at break, shore hardness and water absorption were determined at different weight fraction of filler (0, 2, 7, 10 and 15%. It was found that the addition of filler increases the modulus of elasticity, elongation at break, shore hardness and impact strength; on other hand, it decreases the tensile strength and tensile strength at a break. Absorption test was carried out in water at different immersion times and different composite .The results of absorption show that it obeys Fick’s law and after the addition of kaolin the amount of absorption decrease. Calcinations kaolin filler produces better mechanical properties , than grain kaolin fillers.

  7. Removal of indigo carmine dye from water to Mg-Al-CO3-calcined layered double hydroxides

    International Nuclear Information System (INIS)

    Layered double hydroxides (LDHs) calcined, denoted as CLDHs, have been shown to recover their original layered structure in the presence of appropriate anions. In the light of this so-called 'memory effect', the removal of indigo carmine (IC), an anionic dye, from aqueous solution by calcined Mg-Al-CO3 LDHs was investigated in batch mode. We looked at the influence of pH values, dye-adsorbent contact time, initial dye concentration and various temperatures of heating of LDHs on the decolorization rate of IC. The adsorption isotherms, described by Freundlich model are L-type. The characterization of the solids CLDHs, both fresh and after removal of IC, by X-ray diffraction and infrared spectroscopy shows that the IC adsorption on CLDHs is enhanced by reconstruction of a matrix hydrotalcite intercaled by the dye, and the intercalation of the organic ion was clearly evidenced by the net increase in the basal spacing from 0.76 nm for [Mg-Al-CO3] to 2.13 nm for the organic derivative

  8. Heavy metal removal and speciation transformation through the calcination treatment of phosphorus-enriched sewage sludge ash.

    Science.gov (United States)

    Li, Rundong; Zhao, Weiwei; Li, Yanlong; Wang, Weiyun; Zhu, Xuan

    2015-01-01

    On the basis of the heavy metal (Cd, As, Pb, Zn, Cu, Cr, and Ni) control problem during the thermochemical recovery of phosphorus (P) from sewage sludge (SS), P-enriched sewage sludge ash (PSSA) was calcined at 1100°C. The effect of organic chlorinating agent (PVC) and inorganic chlorinating agent (MgCl2) on the fixed rate of P removal and the speciation transformation of heavy metal was studied. The removal of heavy metals Cd, Pb, As, Zn, and Cr exhibited an increasing tendency with the addition of chlorinating agent (PVC). However, an obvious peak under 100gCl/kg of PSSA appeared for Cu, owing to the presence of carbon and hydrogen in PVC. MgCl2 was found to be more effective than PVC in the removal of most heavy metals, such that up to 98.9% of Cu and 97.3% of Zn was effectively removed. Analyses of heavy metal forms showed that Pb and Zn occurred in the residue fraction after calcination. Meanwhile, the residue fraction of Cr, Ni, Cd, and Cu exhibited a decreasing tendency with the increase in the added chlorinating agent (MgCl2). Losses of P from PSSA were around 16.6% without the addition of chlorinating agent, which were greatly reduced to around 7.7% (PVC) and to only 1.7% (MgCl2).

  9. Photocatalytic Activity and Photocurrent Properties of TiO2 Nanotube Arrays Influenced by Calcination Temperature and Tube Length

    Science.gov (United States)

    Hou, Jian; Zhang, Min; Yan, Guotian; Yang, Jianjun

    2012-06-01

    In this article, titanium oxide nanotube arrays (TiO2-NTAs) were fabricated by anodic oxidation in an ethylene glycol (EG) electrolyte solution containing 0.25 wt.% NH4F. By varying anodized time and annealed temperature, the obtained nanotube arrays behaved different photocatalytic (PC) activities and photocurrent properties. These samples were characterized by scanning electronic microscope (SEM), X-ray powder diffraction (XRD). It was indicated in SEM images that TiO2 nanotube manifests highly ordered structure which, however, has been completely destroyed when the temperature comes to 800°C. XRD manifested that TiO2 nanotubes with various kinds of length all possessed anatase crystallite when annealed at 500°C; meanwhile, with certain length, TiO2-NTAs annealed at series calcination temperature range of 300-600°C also presented anatase crystallite, which is gradually enhanced with the increment of temperature. At 700°C, mixed structure was observed which was made up of proportions of overwhelming anatase and toothful rutile. Methyl blue (MB) degradation and photocurrent measurement testified that TiO2-NTAs under 4 h oxidation and 3 h of 600°C calcination manifested the highest activity and photocurrent density.

  10. Reaction process of monazite and bastnaesite mixed rare earth minerals calcined by CaO-NaCl-CaCl2

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The decomposition reactions of monazite and bastnaesite mixed rare earth minerals calcined by CaO-NaCl-CaCl2 were studied by means of TG-DTA and XRD. The results show that the process of the minerals decomposed by CaO involves two steps.The first step occurs in the temperature range of 425-540 ℃, and the main reactions are bastnaesite decomposition, i.e. REOF reacts with CaO to produce RE2O3 and CaF2, and Ce2O3 is oxidized to CeO2. During this step, CaCO3 is formed at about 500 ℃. The second step takes place in the temperature range of 610-700 ℃, and the reactions are monazite decomposition into RE2O3,Ca5F(PO4)3 and Ca3(PO4)2 by CaO and CaF2. In this process, the decomposition ability is improved because CaO from CaCO3decomposing has high chemical activity. In calcining process, the new formed Ca5F(PO4)3 restrains fluorine that can escape in form of gaseous compound. The decomposition ratio of the mixed rare earth minerals reaches 90.8% at 700 ℃.

  11. Sorption Removal of Pb(Ⅱ) from Solution by Uncalcined and Calcined MgAl-Layered Double Hydroxides

    Institute of Scientific and Technical Information of China (English)

    ZHANG, Shu-Qin; HOU, Wan-Guo

    2007-01-01

    Layered double hydroxide (LDH) with a Mg/Al molar ratio of 1∶1 was synthesized by using a co-precipitation method and its calcined product (CLDH) was obtained by calcination of the MgAl-LDH at 500 ℃. The sorption removal of Pb2+ from solution was investigated, finding that both LDH and CLDH show good sorption ability and they could be used as a new type of environmental sorbent for the removal of Pb2+ from water. The sorption kinetics and the sorption isotherms of Pb2+ on both LDH and CLDH can be described by the pseudo-second order kinetics and Freundlich isotherm, respectively, under the studied conditions. The sorption amounts of Pb2+ on LDH and CLDH are independent of pH in a pH range of about 3-10. The presence of NaNO3 may inhibit the sorption of Pb2+ on LDH while hardly affect that on CLDH. The sorption mechanism of Pb2+ on LDH and CLDH may be attributed to the surface precipitation and the surface complex adsorption. The surface complex adsorption may be further distinguished to the chemical binding adsorption forming the inner-sphere surface complexes and the electrostatic binding adsorption forming the outer-sphere surface complexes. The sorption mechanism of Pb2+ on LDH may be attributed to the surface precipitation and the electrostatic binding adsorption, while that on CLDH may be attributed to the surface precipitation and the chemical binding adsorption.

  12. Electro-oxidation nitrite based on copper calcined layered double hydroxide and gold nanoparticles modified glassy carbon electrode

    Energy Technology Data Exchange (ETDEWEB)

    Cui Lin; Meng Xiaomeng; Xu Minrong; Shang Kun [College of Chemistry and Material Science, Shandong Agricultural University, Taian 271018, Shandong (China); Ai Shiyun, E-mail: ashy@sdau.edu.cn [College of Chemistry and Material Science, Shandong Agricultural University, Taian 271018, Shandong (China); Liu Yinping [College of Chemistry and Material Science, Shandong Agricultural University, Taian 271018, Shandong (China)

    2011-11-30

    Highlights: > A nitrite sensor fabricated based on copper calcined layered double hydroxides and gold nanoparticles modified electrode. > This sensor exhibited excellent electrocatalytic oxidation to nitrite. > This nitrite sensor exhibited very good analytical performance with low cost, convenient preparation and rapid detection. - Abstract: In this paper, a novel nitrite sensor was constructed based on electrodeposition of gold nanoparticles (AuNPs) on a copper calcined layered double hydroxide (Cu-CLDH) modified glassy carbon electrode. Electrochemical experiments showed that AuNPs/CLDH composite film exhibited excellent electrocatalytic oxidation activity with nitrite due to the synergistic effect of the Cu-CLDH with AuNPs. The fabricated sensor exhibited excellent performance for nitrite detection within a wide concentration interval of 1-191 {mu}M and with a detection limit of 0.5 {mu}M. The superior electrocatalytic response to nitrite was mainly attributed to the large surface area, minimized diffusion resistance, and enhanced electron transfer of the Cu-CLDH and AuNPs composition film. This platform offers a novel route for nitrite sensing with wide analytical applications and will supply the practical applications for a variety of simple, robust, and easy-to-manufacture analytical approaches in the future.

  13. Carbothermic reduction of electric arc furnace dust and calcination of waelz oxide by semi-pilot scale rotary furnace

    Directory of Open Access Journals (Sweden)

    Morcali M.H.

    2012-01-01

    Full Text Available The paper gives a common outline about the known recycling techniques from electric arc furnace dusts and describes an investigation of a pyrometallurgical process for the recovery of zinc and iron from electric arc furnace dusts (EAFD. In the waelz process, the reduction of zinc and iron from the waste oxides using solid carbon (lignite coal was studied. In the reduction experiments; temperature, time and charge type (powder and pellet were investigated in detail. It was demonstrated that zinc and iron recovery (% increases with increasing temperature as well as time. Pelletizing was found to be a better method than using the powder as received for the zinc recovery and iron conversion (. In the calcination (roasting process, crude zinc oxide, which evaporated from non-ferric metals were collected as condensed product (crude waelz oxide, was heated in air atmosphere. Lead, cadmium as well as chlorine and other impurities were successfully removed from crude waelz oxide by this method. In the calcination experiments; temperature and time are investigated in detail. It was demonstrated that zinc purification (% increases with increasing temperature. The highest zinc refining (% was obtained at 1200°C for 120 minutes. A kinetic study was also undertaken to determine the activation energy of the process. Activation energies were 242.77 kJ/mol for the zinc recovery with powder forms, 261.99 kJ/mol for the zinc recovery with pellet forms respectively. It was found that, initially, the reaction was chemically controlled.

  14. An interdisciplinary physical-chemical approach for characterization of arsenic in a calciner residue dump in Cornwall (UK).

    Science.gov (United States)

    van Elteren, Johannes Teun; Slejkovec, Zdenka; Arcon, Iztok; Glass, Hylke-Jan

    2006-02-01

    During the later stages of hard-rock mining in Cornwall, UK, widespread processing and refining of arsenic in purpose-built calciners resulted in severe, localized contamination of soils with arsenic. Several physical-chemical techniques were applied to characterize arsenic in a calciner residue dump: X-ray powder diffraction (XRD), sequential extraction combined with hyphenated speciation methods, and X-ray absorption spectroscopic (XAS) methods such as XANES (X-ray absorption near-edge structure) and EXAFS (extended X-ray absorption fine structure). Arsenic was predominantly present in pentavalent form, bound to amorphous or poorly-crystalline hydrous oxides of Fe (probably alpha-hematite). A small amount of a non-classified crystalline iron arsenate phase was found, viz. Fe2(As(AsO4)3). There was also evidence for the presence of some arsenate bound to quartz (alpha-SiO2). The overall results make us believe that the normally assumed relative safety, from a mobility point of view, is questionable since only a small fraction of arsenic is found in a crystalline iron arsenate form.

  15. Continuous production of biodiesel from cottonseed oil and methanol using a column reactor packed with calcined sodium silicate base catalyst☆

    Institute of Scientific and Technical Information of China (English)

    Xia Gui; Sichen Chen; Zhi Yun

    2016-01-01

    Sodium silicate and that calcined at 400 °C for 2 h were used to catalyze the transesterification of cottonseed oil with methanol. Calcined sodium silicate (CSS) catalyst exhibited much higher catalytic activity and stability. A maximum biodiesel yield of 98.9%was achieved at methanol/oil mole ratio of 12:1, reaction temperature 65 °C, reaction time 3.0 h, and CSS/oil mass ratio of 2 wt%. After 7 consecutive reactions without any treatment, biodiesel yield reduced to 82.5%. Considering technological and economic feasibility, CSS base catalyst supported onθrings was prepared for continuous transesterification. The maximum yield was 99.1%under optimum conditions (reaction temperature 55 °C, methanol velocity 1 ml·min−1, oil velocity 3 ml·min−1, and 5 tower sec-tions). These results indicate that this new continuous biodiesel production process and apparatus present a great potential for industrial application in biodiesel.

  16. Effect of Different Calcination Temperatures on the Structural and Photocatalytic Performance of Bi-TiO2/SBA-15

    Directory of Open Access Journals (Sweden)

    Jing Ma

    2013-01-01

    Full Text Available The new novel material Bi-TiO2/SBA-15 was synthesized by an easy wet impregnation method. A combination of XRD, XPS, Raman, N2 adsorption-desorption isotherm measurement, TEM, and solid state UV-Vis spectroscopy has been used to characterize the Bi-TiO2/SBA-15 material. It was found that SBA-15 retained the ordered hexagonal mesostructure after incorporation of TiO2 and Bi. The photodecomposition of rhodamine B (RhB in aqueous medium was selected to evaluate the photocatalytic performance of Bi-TiO2/SBA-15 under visible light irradiation (λ≥420 nm. The experiment results indicated that Bi-TiO2/SBA-15 exhibited higher photocatalytic activities than pure TiO2 and Bi2O3. The influences of calcination temperature were studied. It strongly influenced the activity of the samples. The sample calcined at 550°C shows the highest photocatalytic activity in the decomposition of RhB under visible light. The catalyst preserved almost its initial photocatalytic activity after six reuses.

  17. Spring 2009 Semiannual (III.H. and I.U.) Report for the HWMA/RCRA Post-Closure Permit for the INTEC Waste Calcining Facility at the INL Site

    Energy Technology Data Exchange (ETDEWEB)

    Boehmer, Ann M.

    2009-05-31

    The Waste Calcining Facility is located at the Idaho Nuclear Technology and Engineering Center. In 1999, the Waste Calcining Facility was closed under and approved Hazardous Waste Management Act/Resource Conservation and Recovery Act Closure plan. Vessels and spaces were grouted and then covered with a concrete cap. This permit sets forth procedural requirements for groundwater characterization and monitoring, maintenance, and inspections of the Waste Calcining Facility to ensure continued protection of human health and the environment.

  18. Preferential oxidation of CO in excess H2 over CeO2/CuO catalyst: Effect of calcination temperature

    Institute of Scientific and Technical Information of China (English)

    Zhiming Gao; Ming Zhou; Hao Deng; Yong Yue

    2012-01-01

    Different from the classical configuration CuO/CeO2 catalyst,the inverse configuration CeO2/CuO catalyst (atomic ratio of Ce/Cu=10/100)was prepared by impregnation method.Five calcination temperatures were selected to investigate the interaction between CeO2 and CuO support.It is found that as calcination temperature increased from 500 to 900 ℃,sintering of CeO2 particles on the support occurred together with the diffusion of a portion of Ce4+ ions into CuO crystals,forming solid solution.Formation of interface complex Ce-O-Cu was suggested by TPR measurements.The catalyst calcined at 700℃ gives the highest activity for preferential oxidation of CO in excess H2 stream.

  19. Study on Improving Whiteness of Tripoli by Calcination%粉石英煅烧增白工艺技术研究

    Institute of Scientific and Technical Information of China (English)

    葛鹤松; 李舟; 李浩; 蔡有兴

    2011-01-01

    Taking tripoli from Liuyang in Hu(n)an province as a sample, the experiments of calcination were carried out. The factors which affected the whiteness of tripoli were studied, such as the amount of brightening agent, calcining heat, calcining time, the particle size of raw tripoli and so on. The whiteness of tripoli product was more than 90% in the pilot test.%采用我国浏阳粉石英矿为原料,通过煅烧试验,考察了增白剂用量、煅烧温度、煅烧时间、原矿粒度等因素对粉石英白度的影响,放大试验获得粉石英产品的白度均大于90%.

  20. Effect of support calcination temperature on the Ru-Ce-B/ZrO_2 catalysts for benzene selective hydrogenation to cyclohexene

    Institute of Scientific and Technical Information of China (English)

    HAN Jianhua; LI Lichao

    2011-01-01

    The effect of support calcination temperature on the benzene selective hydrogenation performance of the Ru-Ce-B/ZrO2 catalysts was investigated.It was found that with increasing calcination temperature,the surface area decreased,on the contrary,the pore size and the amount of monoclinic phase increased.With increasing support calcination temperature,the activity of the catalyst roughly decreased and cyclohexene selectivity increased.The activity decreased due to the decrease of the surface areas.The increase of the cyclohexene selectivity was correlated not only with the decrease of the surface areas but also with the increase of monoclinic phases,rich in surface hydroxyl,and the enlarged pore size of zirconia.This suggests the monoclinic zirconia with a medium surface area,rather than a big one,and a mesoporous structure,even including some macropores,is an ideal support of the catalyst for benzene selective hydrogenation.

  1. HYDROESTERIFICATION OF ACETYLENE WITH METHYL FORMATE TO METHYL ACRYLATE OVER A NiO/Al203 CATALYST: EFFECTS OF NiO LOADING AND CALCINATION TEMPERATURE

    Institute of Scientific and Technical Information of China (English)

    Huang Xinhan; Yang Xiangui; Zhang Jiaqi; Liu Zhaotie

    2001-01-01

    Hydroesterification of acetylene with methyl formate (MF) was studied over a series of nickel-supported catalysts with NiO loading varing from 0.8 wt% to 18.7 wt% and calcination temperature ranging from 623 K to 873 K. The catalyst was studied by TPR, XPS, XRD and BET. The interactions between impregnated Ni2+ and alumina during catalyst preparation produced different kinds of nickel species such as NiO crystallites and NiAl2O4-like species, and their distributions varied with NiO loading and calcination temperature, which leads to different activities of catalyst in hydroesterification of acetylene with methyl formate. Experimental results indicated that 10wt% NiO/Al2O3 calcined at 773 K is suitable for the hydroesterification of acetylene with methyl formate.

  2. Influence of calcination temperature on the performance of Pd-Mn/SiO2-Al2O3 catalysts for ozone decomposition

    International Nuclear Information System (INIS)

    The catalytic decomposition of ozone was investigated over Pd-Mn/SiO2-Al2O3 catalysts in the ground air. The catalysts were prepared by incipient wetness impregnation method and characterized by powder X-ray diffraction (XRD), thermo gravimetric (TG) analysis, and N2 adsorption/desorption measurements (Brunauer-Emmet-Teller method). The influence of calcination temperature on the catalytic activities, and the lifetime test of the catalyst pretreated at 350 deg. C had been studied. XRD and TG results show that when calcined in the temperature range of 300-450 deg. C, manganese carbonate (MnCO3) is partly decomposed to MnOx (x = 1.6-2.0) species in the catalysts. However, when calcined at 500 deg. C, MnOx partly turns into Mn2O3 in the catalyst. The catalytic activity test indicates that the catalysts calcined at 300-400 deg. C exhibit the best performance for O3 decomposition, and the completely conversion temperature of ozone (T100) is in the region of 30-35 deg. C, which is lower than surface temperature of water tanks of running automobile. Under gas hour space velocity (GHSV) of 635,000 h-1 and reaction temperature of 40 deg. C, after lifetime test for 80 h, the catalyst calcined at 350 deg. C keeps 90% conversion, which indicates that they have excellent ability to resist deactivation. The catalysts calcined at 300-400 deg. C show great potential to be applied at lower temperature, especially in winter and at the stage of automobile engine cold start.

  3. Thermal and catalytic cracking of ethylene in presence of CaO, MgO, zeolite and calcined dolomite

    Energy Technology Data Exchange (ETDEWEB)

    Taralas, G.; Sjoestroem, K.; Jaeraas, S.; Bjoernbom, E. [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Chemical Technology

    1993-12-31

    The subject of the present work is to study the effect of catalysts such as calcined dolomite (CaO.MgO), CaO (quicklime), MgO and Zeolite (EKZ-4) on the cracking of ethylene in the presence and absence of steam. N-heptane, toluene, naphthalene, thiophene have been some suitable model compounds for studies of the thermal and catalytic decomposition of tar. Previous results showed that the reaction scheme of the thermal decomposition of n-heptane was consistent with the high yield of ethylene observed in thermal decomposition of n-heptane. The effect of the reactor wall and the ferric impurities in the dolomite are also subjects of the research in this study. The results may also throw some additional light on the nature of the gas-phase thermal and catalytic reactions occurring in the use of dolomite as tar cracking catalysts. 28 refs

  4. Effectiveness factors for a commercial steam reforming (Ni) catalyst and for a calcined dolomite used downstream biomass gasifiers

    Energy Technology Data Exchange (ETDEWEB)

    Corella, J.; Narvaez, I.; Orio, A. [Madrid Univ. (Spain). Dept. of Chem. Eng.

    1996-12-31

    A commercial steam reforming catalyst from BASF, the G1-25 S one, and a calcined dolomite, Norte-1, from Cantabria-Spain, have been used, once crushed and sieved to different particle fractions between 1.0 and 4.0 mm. The materials have been tested downstream small pilot biomass gasifiers, bubbling fluidized bed type, gasifying with air and with steam. The Thiele modulus and the effectiveness factor have been calculated at temperatures of 750-850 deg C. It is experimentally shown that diffusion control plays an important part when particle size is larger than ca. 0.5 mm. This has to be taken into account when comparing the quality of the solids for tar elimination. (author) (5 refs.)

  5. Effects of surface features on sulfur dioxide adsorption on calcined NiAl hydrotalcite-like compounds.

    Science.gov (United States)

    Zhao, Ling; Li, Xinyong; Quan, Xie; Chen, Guohua

    2011-06-15

    The hydrotalcite-based NiAl mixed oxides were synthesized by coprecipitation and urea hydrolysis approaches and employed for SO₂ removal. The samples were well characterized by inductively coupled plasma (ICP) elemental analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and N₂ adsorption/desorption isotherm analyses. The acid-base properties were characterized by pyridine chemisorption and CO₂ temperature-programmed desorption (TPD). The calcined NiAlO from the urea method showed excellent SO₂ adsorption and its adsorption equilibrium showed a type I isotherm, which significantly improved the adsorption performance for low-concentration SO₂. Both the physical structure and the acidic-basic sites were found to play important roles in the SO₂ adsorption process. In situ Fourier transform infrared spectroscopy (FTIR) investigation revealed that adsorbed SO₂ molecules formed surface bisulfite, sulfite, and bidentate binuclear sulfate. The mechanisms for SO₂ adsorption and transformation are discussed in detail. PMID:21609013

  6. Synthesis of nano-hollow-shaped rare earth oxides by glycothermal treatment of rare earth acetates and subsequent calcination

    International Nuclear Information System (INIS)

    The reaction of yttrium acetate hydrate in 1,2-propanediol (1,2-PG) at 300 deg. C yielded the products containing the acetate groups and the glycol moieties. The products decomposed into Y2O3 below 400 deg. C, and the thus-obtained Y2O3 samples had quite large surface areas (>200 m2/g) and were comprised of crystalline nano-hollow spheres with the outer diameter of 7-18 nm and the inner diameter of 2-8 nm. Dy2O3, Er2O3 and Yb2O3 composed of nano-hollow spheres were also obtained by the glycothermal treatment and subsequent calcination

  7. Sorption kinetics and equilibrium for the removal of nickel ions from aqueous phase on calcined Bofe bentonite clay

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, M.G.A.; Neto, A.F. Almeida [UNICAMP/FEQ/DTF, Campinas/SP (Brazil); Gimenes, M.L. [UEM/CTC/DEQ, Maringa/PR (Brazil); Silva, M.G.C. da, E-mail: meuris@feq.unicamp.br [UNICAMP/FEQ/DTF, Campinas/SP (Brazil)

    2010-05-15

    In this paper the kinetics and dynamics of nickel adsorption on calcined Bofe bentonite clay were studied. The clay was characterized through EDX, surface area (BET) and XRD analysis. The influence of parameters (pH, amount of adsorbent, adsorbate concentration and temperature) was investigated. Kinetic models were evaluated in order to identify potential adsorption process mechanisms. The Langmuir and Freundlich models were utilized for the analysis of adsorption equilibrium. Thermodynamic parameters were assessed as a function of the process temperature. The kinetics data were better represented by the second-order model. The process was found to be strongly influenced by the factors studied. The Bofe clay removed nickel with maximum adsorption capacity of 1.91 mg metal/g of clay (20 deg. C; pH 5.3) and that the thermodynamic data indicated that the adsorption reaction is spontaneous and of an exothermal nature. The Langmuir model provided the best fit for sorption isotherms.

  8. Preparation of strontium hexaferrite nano-crystalline powder by carbon monoxide heat treatment and re-calcination from conventionally synthesized powder

    International Nuclear Information System (INIS)

    In this work strontium hexaferrite nano-crystalline powders were prepared by carbon monoxide heat treatment and re-calcination from conventionally synthesized powder. First strontium hexaferrite was obtained by the conventional route with calcination of strontium carbonate and hematite at 1100 deg. C for 1 h. Then strontium hexaferrite was isothermally subjected to carbon monoxide dynamic atmosphere at various temperatures and flows for different times. Optimum carbon monoxide heat treatment was achieved at 850 deg. C with 20 cm3/min flow for 0.5 h. The resultant powder was then calcined at 900 and 1000 deg. C for 1 h. The single-phase strontium hexaferrite nano-crystalline powder was finally obtained after calcination at 1000 deg. C. The phase identification of the powders was recorded by an X-ray diffractometer (XRD) with Cu Kα radiation. Morphology and size of the particles were studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. The magnetic properties were also measured by a vibration sample magnetometer (VSM). The results show a good enhancement in the coercivity by applying this method on the hexaferrite powder

  9. Influence of lithium precursors and calcination atmospheres on graphene sheets-modified nano-Li4Ti5O12 anode material

    Science.gov (United States)

    Li, Wen-Ting; Yuan, Tao; Zhang, Weimin; Ma, Jingjing; Zhang, Chunming; He, Yu-Shi; Liao, Xiao-Zhen; Ma, Zi-Feng

    2015-07-01

    The influence of Li precursors and calcination atmospheres on the reaction mechanisms, physical properties and electrochemical performance of graphene sheets (GS)-modified nano-Li4Ti5O12 (LTO/GS) has been systematically investigated. Field emission scanning electron microscopy (FE-SEM) and mass spectrometry (MS) results demonstrate the lithium precursor containing carboxyl anion such as lithium acetate (LiAc) and Li2CO3 interact with oxygen groups of graphene oxide (GO) by strong hydrogen bonds to restrict the morphology and the phase formation of products. We also notice from the thermogravimetry (TG) and MS results that the consumption of GS is proportional to oxygen content of lithium precursor. Cyclic voltammetry (CV) and X-ray photoelectric spectroscopy (XPS) results indicate that the product calcined in reducing atmosphere possess smaller electrochemical polarization due to more reduced Ti3+ on the surface of the product. The LTO/GS sample with LiOH as Li precursor calcined in diluted hydrogen atmosphere show the best electrochemical performance with a capacity of 134.4 mAh g-1 at 10C discharge rate and very stable cycling life with a 98.6% capacity retention after 800 cycles at 40C rate. This study not only provides an optimization of Li precursor and calcination condition for LTO/GS anode material, but also guides any future one-step syntheses of lithium composite materials with GO participation.

  10. CO and C3H8 total oxidation over Pd/La-Al2O3 catalysts:Effect of calcination temperature and hydrothermal treatment

    Institute of Scientific and Technical Information of China (English)

    周仁美; 邢丰; 王树元; 鲁继青; 金凌云; 罗孟飞

    2014-01-01

    A series of Pd/La-Al2O3 (PLA) catalysts with La-Al2O3 (LA) support calcined at different temperatures (500, 700, 900 and 1050 ºC) were prepared using an incipient wetness impregnation method. The activity of the fresh and hydrothermally aged PLA catalysts were tested for total oxidation of CO and C3H8. The activity of the fresh PLA catalysts for CO and C3H8 oxidation increased with increasing calcination temperature of the support, while the activities of the aged catalysts declined and became essentially the same. CO chemisorption results revealed that the suppressed activities of the aged catalysts were mainly due to the decline of palla-dium dispersion. The turnover frequency (TOF) of CO oxidation increased with increasing reduction ability of the catalysts, with a fresh catalyst calcined at 1050 ºC having the highest value (0.048 s-1). However, the TOF of C3H8 total oxidation was affected by not only the redox properties of catalysts but also the size of Pd particle, and large Pd particles possessed higher TOF value of C3H8 oxi-dation, with the highest value (0.125 s-1) being obtained on an aged catalyst calcined at 500 ºC.

  11. Influence of calcination temperature on the morphology and energy storage properties of cobalt oxide nanostructures directly grown over carbon cloth substrates

    KAUST Repository

    Rakhi, R. B.

    2013-09-23

    Nanostructured and mesoporous cobalt oxide (Co3O4) nanowire in flower-like arrangements have been directly grown over flexible carbon cloth collectors using solvothermal synthesis for supercapacitor applications. Changes in the morphology and porosity of the nanowire assemblies have been induced by manipulating the calcination temperature (200–300 °C) of the one-dimensional (1-D) structures, resulting in significant impact on their surface area and pseudocapacitive properties. As the calcination temperature increases from 200 to 250 °C, the flower morphology gradually modifies to the point where the electrolyte could access almost all the nanowires over the entire sample volume, resulting in an increase in specific capacitance from 334 to 605 Fg−1, depending on the nanowire electrode morphology. The 300 °C calcination results in the breakdown of the mesoporous morphology and decreases the efficiency of electrolyte diffusion, resulting in a drop in pseudocapacitance after 300 °C. A peak energy density of 44 Wh kg−1 has been obtained at a power density of 20 kW kg−1 for the 250 °C calcined sample.

  12. Effect of calcination temperature on physical parameters and photocatalytic activity of mesoporous titania spheres using chitosan/poly(vinyl alcohol) hydrogel beads as a template

    Science.gov (United States)

    Jiang, R.; Zhu, H.-Y.; Chen, H.-H.; Yao, J.; Fu, Y.-Q.; Zhang, Z.-Y.; Xu, Y.-M.

    2014-11-01

    Mesoporous titania spheres were prepared by modified sol-gel method using chitosan/poly(vinyl alcohol) hydrogel beads as a template. Effects of calcination temperature on physical parameters were investigated by X-ray diffraction (XRD), N2 adsorption-desorption, Fourier transform infrared (FT-IR) spectra, thermogravimetry and differential thermal analyses (TG-DTA), high-resolution transmission electron microscope (HRTEM) and scanning electron microscopy (SEM). The photocatalytic activity of mesoporous titania spheres prepared was also evaluated by photocatalytic degradation of phenol as a model molecule under UV irradiation. With increasing calcination temperature, average crystallite size and pore size increased. In contrast, Brunauer-Emmett-Teller (BET) specific surface areas, porosity and pore volumes steadily decreased. Results of characterization proved that prepared titania spheres with highly organized pores were mesoporous structure. The photocatalytic activity of mesoporous titania spheres calcined at 500 °C was more effective than those calcined at other temperatures, which were attributed to the porous structure, large BET surface area, crystalline, and smaller crystallite size. This work may provide new insights into the preparation of novel mesoporous titania spheres and further practical applications in the treatment of wastewater.

  13. Photoluminescence and abnormal reduction of Eu{sup 3+} ions in CaAl{sub 2}O{sub 4}:EU nanophosphors calcined in air atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yin; Chen, Jie [College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Xu, Chuanyan [Suzhou Biomaterials and Advanced Manufacture Engineering Technology Research Center, Suzhou Dingan Technology Co. Ltd, Suzhou 215200 (China); Li, Yadong, E-mail: liyadong@suda.edu.cn [College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Jin Seo, Hyo [Department of Physics and Interdisciplinary Program of Biomedical Engineering, Pukyong National University, Busan 608737 (Korea, Republic of)

    2015-09-01

    Precursor of Europium doped calcium aluminate (CaAl{sub 2}O{sub 4}: Eu) was prepared by the Pechini technique. The synthesized samples were calcined at 900–1500 °C for 2 h in air atmosphere. The crystal structures of calcined samples at low and high temperatures were found to be the metastable hexagonal and stable monoclinic systems by X-ray powder diffraction (XRD) analysis, respectively. The effects of Eu content and valence state on the luminescence characteristics of CaAl{sub 2}O{sub 4}: Eu were studied by luminescence spectrometer (LS). With the increase in calcination temperature, the phosphors exhibited color change from bright red to violet upon excitation by UV-light and an abnormal reduction of Eu{sup 3+}→Eu{sup 2+} was observed in monoclinic phase of CaAl{sub 2}O{sub 4}: Eu that calcined in air atmosphere at high temperature. The reduction mechanism was explained reasonably by a rigid three-dimensional framework structure of the stable monoclinic phase of CaAl{sub 2}O{sub 4}: Eu and a charge compensation model.

  14. Effects of Different Salts on Salt-Assisted Ultrasonic Spray Pyrolysis (SA-USP) Calcination for the Synthesis of Strontium Ferrite.

    Science.gov (United States)

    Hwang, Tea-Yeon; An, Guk-Hwan; Cho, Jeong-Ho; Kim, Jongryoul; Choa, Yong-Ho

    2015-10-01

    Strontium ferrite (hexaferrite), SrFe12O19, was successfully fabricated in sizes ranging from hundreds of nanometers to several micrometers by salt-assisted ultrasonic spray pyrolysis-calcination using different salt media. All samples were single phases of SrFe12O19 without the intermediate phase, α-Fe2O3, and their morphology was hexagonal. As calcination temperature increased, the size of as-calcined samples and saturation magnetization, Ms, increased while coercivity decreased. The particle size of the obtained nanoparticles varied depending on the salt media and calcination temperatures. The best magnetic properties obtained in this experiment were a coercivity of 6973 Oe with a saturation magnetization of 68.3 emu/g. To the best of our knowledge, these coercivity values are the highest ever obtained. We propose a detailed mechanism explaining the growth of these particles and conclude that the resulting single-domain particle size is about 70 nm, taking into account of factors affecting coercivity in ferrite nano- to micro-sized particles. PMID:26726463

  15. Preparation of Calcined Zirconia-Carbon Composite from Metal Organic Frameworks and Its Application to Adsorption of Crystal Violet and Salicylic Acid

    Directory of Open Access Journals (Sweden)

    Zubair Hasan

    2016-03-01

    Full Text Available Zirconia-carbon (ZC composites were prepared via calcination of Zr-based metal organic frameworks, UiO-66 and amino-functionalized UiO-66, under N2 atmosphere. The prepared composites were characterized using a series of instrumental analyses. The surface area of the ZC composites increased with the increase of calcination temperature, with the formation of a graphite oxide phase observed at 900 °C. The composites were used for adsorptive removal of a dye (crystal violet, CV and a pharmaceutical and personal care product (salicylic acid, SA. The increase of the calcination temperature resulted in enhanced adsorption capability of the composites toward CV. The composite calcined at 900 °C exhibited a maximum uptake of 243 mg·g−1, which was much greater than that by a commercial activated carbon. The composite was also effective in SA adsorption (102 mg·g−1, and N-functionalization of the composite further enhanced its adsorption capability (109 mg·g−1. CV adsorption was weakly influenced by solution pH, but was more dependent on the surface area and pore volume of the ZC composite. Meanwhile, SA adsorption showed strong pH dependence, which implies an active role of electrostatic interactions in the adsorption process. Base-base repulsion and hydrogen bonding are also suggested to influence the adsorption of CV and SA, especially for the N-functionalized composite.

  16. Study on process parameters for activating fly ash with alkali by calcination%加碱煅烧活化粉煤灰工艺参数研究

    Institute of Scientific and Technical Information of China (English)

    吴勇勇; 周勇敏; 张苏伊

    2012-01-01

    The calcination process for activating fly ash with Na2CO3 as accessory ingredient was investigated.The concenta-tions of Si and A1 in the fly ash activated under different calcination conditions (calcination temperature and calcination time), that dissolved in the sodium hydroxide solution were measured by titering process.The phase composition of fly ash obtained under different calcination conditions (mass ratio of fly ash and sodium carbonate ) was characterized by XRD.The best process parameters were obtained as follows: calcination temperature was 875 X. .holding time was 1.5 h,and mass ratio of fly ash and sodium carbonate was 1:0.87.The products after calcination were mainly made up of soluble NaAlSiO4 and Na2SiO3,and the quartz and mullitein in the raw fly ash both almost disappeared.Therefore, the fly ash was activated adequately.%研究了以碳酸钠为助剂活化粉煤灰的煅烧工艺.采用滴定法测定不同煅烧条件(煅烧温度和煅烧时间)所得活化粉煤灰溶解在氢氧化钠溶液中的硅、铝浓度,并采用X射线衍射(XRD)表征不同煅烧条件(灰碱质量比)所得活化粉煤灰的物相组成,得出粉煤灰较佳煅烧工艺参数:煅烧温度为875℃,保温时间为1.5 h,粉煤灰与碳酸钠的质量比为1∶0.87.煅烧后的产物主要以可溶性的硅铝酸钠(NaAlSiO4)和硅酸钠(Na2SiO3)为主,原粉煤灰中的石英、莫来石基本消失,粉煤灰得到充分活化.

  17. Facile synthesis of both needle-like and spherical hydroxyapatite nanoparticles: Effect of synthetic temperature and calcination on morphology, crystallite size and crystallinity

    International Nuclear Information System (INIS)

    Synthetic hydroxyapatite (HA) nanoparticles, that mimic natural HA, are widely used as biocompatible coatings on prostheses to repair and substitute human bones. In this study, HA nanoparticles are prepared by precipitating them from a precursor solution containing calcium sucrate and ammonium dihydrogen orthophosphate, at a Ca/P mole ratio of 1.67:1, at temperatures, ranging from 10 °C to 95 °C. A set of products, prepared at different temperatures, is analyzed for their crystallinity, crystallite size, morphology, thermal stability and composition, by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and Fourier transform infrared (FT-IR) spectroscopic techniques, while the other set is analyzed after calcining the respective products, soon after their synthesis, for 3 h, at 700 °C. The as-prepared products, after 2 h of drying, without any calcination, are not crystalline, but they grow very slowly into needle-like morphologies, as they are ripened with time. The percentage crystallinity of the final products increases from 15% to 52%, with increasing the preparative temperature. The calcined samples always produce spherical nanoparticles of essentially the same diameter, between 90 nm and 100 nm, which does not change due to aging and preparative temperatures. Therefore, the same method can be utilized to synthesize both spherical and needle-like nanoparticles of hydroxyapatite, with well-defined sizes and shapes. The ability to use readily available cheap raw materials, for the synthesis of such well-defined crystallites of hydroxyapatite, is an added advantage of this method, which may be explored further for the scaling up of the procedures to suit to industrial scale synthesis of such hydroxyapatite nanoparticles. - Highlights: • Hydroxyapatite nanoparticles are synthesized using a simple precipitation method. • Both needle-like and spherical hydroxyapatite nanoparticles are synthesized. • The prepared

  18. Facile synthesis of both needle-like and spherical hydroxyapatite nanoparticles: Effect of synthetic temperature and calcination on morphology, crystallite size and crystallinity

    Energy Technology Data Exchange (ETDEWEB)

    Wijesinghe, W.P.S.L.; Mantilaka, M.M.M.G.P.G. [Department of Chemistry, Faculty of Science, University of Peradeniya, Peradeniya 20400 (Sri Lanka); Post-graduate Institute of Science, P.O. Box: 25, University of Peradeniya, Peradeniya 20400 (Sri Lanka); Premalal, E.V.A. [Department of Materials Science, Shizuoka University, Johoku, Naka-ku Hamamatsu, 432-8011 (Japan); Herath, H.M.T.U. [Department of Medical Laboratory Science, Faculty of Allied Health Sciences, University of Peradeniya, Peradeniya 20400 (Sri Lanka); Mahalingam, S.; Edirisinghe, M. [Department of Mechanical Engineering, University College London, London WC1E 7JE (United Kingdom); Rajapakse, R.P.V.J. [Department of Veterinary Pathobiology, Faculty of Veterinary, University of Peradeniya, Peradeniya 20400 (Sri Lanka); Rajapakse, R.M.G., E-mail: rmgr@pdn.ac.lk [Department of Chemistry, Faculty of Science, University of Peradeniya, Peradeniya 20400 (Sri Lanka); Post-graduate Institute of Science, P.O. Box: 25, University of Peradeniya, Peradeniya 20400 (Sri Lanka)

    2014-09-01

    Synthetic hydroxyapatite (HA) nanoparticles, that mimic natural HA, are widely used as biocompatible coatings on prostheses to repair and substitute human bones. In this study, HA nanoparticles are prepared by precipitating them from a precursor solution containing calcium sucrate and ammonium dihydrogen orthophosphate, at a Ca/P mole ratio of 1.67:1, at temperatures, ranging from 10 °C to 95 °C. A set of products, prepared at different temperatures, is analyzed for their crystallinity, crystallite size, morphology, thermal stability and composition, by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and Fourier transform infrared (FT-IR) spectroscopic techniques, while the other set is analyzed after calcining the respective products, soon after their synthesis, for 3 h, at 700 °C. The as-prepared products, after 2 h of drying, without any calcination, are not crystalline, but they grow very slowly into needle-like morphologies, as they are ripened with time. The percentage crystallinity of the final products increases from 15% to 52%, with increasing the preparative temperature. The calcined samples always produce spherical nanoparticles of essentially the same diameter, between 90 nm and 100 nm, which does not change due to aging and preparative temperatures. Therefore, the same method can be utilized to synthesize both spherical and needle-like nanoparticles of hydroxyapatite, with well-defined sizes and shapes. The ability to use readily available cheap raw materials, for the synthesis of such well-defined crystallites of hydroxyapatite, is an added advantage of this method, which may be explored further for the scaling up of the procedures to suit to industrial scale synthesis of such hydroxyapatite nanoparticles. - Highlights: • Hydroxyapatite nanoparticles are synthesized using a simple precipitation method. • Both needle-like and spherical hydroxyapatite nanoparticles are synthesized. • The prepared

  19. Ni/Al2O3 catalysts for CO methanation: Effect of Al2O3 supports calcined at different temperatures

    Institute of Scientific and Technical Information of China (English)

    Jiajian; Gao; Chunmiao; Jia; Jing; Li; Meiju; Zhang; Fangna; Gu; Guangwen; Xu; Ziyi; Zhong; Fabing; Su

    2013-01-01

    The correlation between phase structures and surface acidity of Al2O3 supports calcined at different temperatures and the catalytic performance of Ni/Al2O3 catalysts in the production of synthetic natural gas(SNG) via CO methanation was systematically investigated. A series of 10 wt% NiO/Al2O3 catalysts were prepared by the conventional impregnation method, and the phase structures and surface acidity of Al2O3 supports were adjusted by calcining the commercial γ-Al2O3 at different temperatures(600–1200 C). CO methanation reaction was carried out in the temperature range of 300–600 C at different weight hourly space velocities(WHSV = 30000 and 120000 mL·g-1h-1) and pressures(0.1 and 3.0 MPa). It was found that high calcination temperature not only led to the growth in Ni particle size, but also weakened the interaction between Ni nanoparticles and Al2O3 supports due to the rapid decrease of the specific surface area and acidity of Al2O3 supports. Interestingly, Ni catalysts supported on Al2O3 calcined at 1200 C(Ni/Al2O3-1200) exhibited the best catalytic activity for CO methanation under different reaction conditions. Lifetime reaction tests also indicated that Ni/Al2O3-1200 was the most active and stable catalyst compared with the other three catalysts, whose supports were calcined at lower temperatures(600, 800 and 1000 C). These findings would therefore be helpful to develop Ni/Al2O3 methanation catalyst for SNG production.

  20. Balanced TH1 and TH2 immunopotentiating effects of silicates partly containing nanoparticles present in calcined serpentine.

    Science.gov (United States)

    Elahi, Asif; Sharma, Yadhu; Bashir, Samina; Khan, Farah

    2016-05-01

    Calcined Serpentine (CS) is used in various formulations of alternative systems of medicine as a tonic to vital organs and as an anti-inflammatory agent. The process of calcination or incineration is believed to render non-toxic, gently absorbable, adaptable and digestible properties to the mineral compounds. The present study characterized CS and also evaluated its immunostimulatory potential. CS was characterized by using transmission electron microscopy (TEM), X-ray powder diffraction, atomic absorption spectroscopy and CHNS analysis. The characterized CS was further evaluated for its immunomodulatory potential in Swiss mice. X-Ray diffraction analysis revealed that the CS contained silicates of magnesium, calcium and iron as major minerals. Elemental composition and heavy metal analyses showed a presence of various inorganic elements/heavy metals, albeit at levels well below daily permissive intake values. TEM analysis of the test CS revealed a presence of nano particles with an average size of 10-20 nm (≈ 26% of total material). Oral administration of CS to mice at 50, 75, 100 or 200 μg/kg body weight for 10 days led to enhanced levels of total IgG, IgG1, IgG2a and IgG2b in ovalbumin-immunized mice as well as ex vivo lymphocyte proliferation and levels of TH1 (IL-2, IFNγ) and TH2 (IL-4, IL-10) cytokines produced by their cultured splenocytes. Similarly, CS treatment resulted in enhanced delayed-type hypersensitivity responses in GRBC-primed hosts. CS also activated host peritoneal macrophages, as indicated by increases in phagocytic activity and in TLR-2, CD80 and CD86 expression. The CS did not affect liver, kidney and spleen histology. Taken together, the results indicated that absorbed CS was stimulatory of host cell-mediated immune responses. It is hypothesized for now that the immunomodulatory effect of CS may have been due, in part, to a presence of nanoparticles on the CS; further study is required to validate this viewpoint. PMID:26484633

  1. LAB-SCALE DEMONSTRATION OF PLUTONIUM PURIFICATION BY ANION EXCHANGE, PLUTONIUM (IV) OXALATE PRECIPITATION, AND CALCINATION TO PLUTONIUM OXIDE TO SUPPORT THE MOX FEED MISSION

    Energy Technology Data Exchange (ETDEWEB)

    Crowder, M.; Pierce, R.

    2012-08-22

    H-Canyon and HB-Line are tasked with the production of PuO{sub 2} from a feed of plutonium metal. The PuO{sub 2} will provide feed material for the MOX Fuel Fabrication Facility. After dissolution of the Pu metal in H-Canyon, the solution will be transferred to HB-Line for purification by anion exchange. Subsequent unit operations include Pu(IV) oxalate precipitation, filtration and calcination to form PuO{sub 2}. This report details the results from SRNL anion exchange, precipitation, filtration, calcination, and characterization tests, as requested by HB-Line1 and described in the task plan. This study involved an 80-g batch of Pu and employed test conditions prototypical of HB-Line conditions, wherever feasible. In addition, this study integrated lessons learned from earlier anion exchange and precipitation and calcination studies. H-Area Engineering selected direct strike Pu(IV) oxalate precipitation to produce a more dense PuO{sub 2} product than expected from Pu(III) oxalate precipitation. One benefit of the Pu(IV) approach is that it eliminates the need for reduction by ascorbic acid. The proposed HB-Line precipitation process involves a digestion time of 5 minutes after the time (44 min) required for oxalic acid addition. These were the conditions during HB-line production of neptunium oxide (NpO{sub 2}). In addition, a series of small Pu(IV) oxalate precipitation tests with different digestion times were conducted to better understand the effect of digestion time on particle size, filtration efficiency and other factors. To test the recommended process conditions, researchers performed two nearly-identical larger-scale precipitation and calcination tests. The calcined batches of PuO{sub 2} were characterized for density, specific surface area (SSA), particle size, moisture content, and impurities. Because the 3013 Standard requires that the calcination (or stabilization) process eliminate organics, characterization of PuO{sub 2} batches monitored the

  2. Morphology and structure features of ZnAl2O4 spinel nanoparticles prepared by matrix-isolation-assisted calcination

    International Nuclear Information System (INIS)

    Graphical abstract: The substrate ZnO as the isolation medium is effective in preventing the sintering and agglomeration of ZnAl2O4 nanoparticles, and it also prevents their contamination. High purity, well-dispersed, and single-crystal ZnAl2O4 nanoparticles with 3.72 eV band gap were obtained. - Abstract: Well-dispersed ZnAl2O4 spinel nanoparticles with an average crystalline size of 25.7 nm were synthesized successfully and easily by polymer-network and matrix-isolation-assisted calcination. The product microstructure and features were investigated by X-ray diffractometry, thermogravimetric and differential thermal analysis, Fourier transform-infrared spectroscopy, N2 adsorption–desorption isotherms, and energy dispersive X-ray spectra. The morphology and optical performance of the as-prepared ZnAl2O4 nanoparticles were characterized by scanning electron microscope, transmission electron microscopy, and photoluminescence spectrometer. Experimental results indicate that excess ZnO acted as the isolation medium is effective in preventing the sintering and agglomeration of ZnAl2O4 nanoparticles, and it also prevents their contamination. Then, high purity and well-dispersed ZnAl2O4 nanoparticles with single-crystal structure were obtained

  3. Hydration mechanism and leaching behavior of bauxite-calcination-method red mud-coal gangue based cementitious materials.

    Science.gov (United States)

    Zhang, Na; Li, Hongxu; Liu, Xiaoming

    2016-08-15

    A deep investigation on the hydration mechanism of bauxite-calcination-method red mud-coal gangue based cementitious materials was conducted from viewpoints of hydration products and hydration heat analysis. As a main hydration product, the microstructure of C-A-S-H gel was observed using high resolution transmission electron microscopy. It was found that the C-A-S-H gel is composed of amorphous regions and nanocrystalline regions. Most of regions in the C-A-S-H gel are amorphous with continuous distribution, and the nanocrystalline regions on scale of ∼5nm are dispersed irregularly within the amorphous regions. The hydration heat of red mud-coal gangue based cementitious materials is much lower than that of the ordinary Portland cement. A hydration model was proposed for this kind of cementitious materials, and the hydration process mainly consists of four stages which are dissolution of materials, formation of C-A-S-H gels and ettringite, cementation of hydration products, and polycondensation of C-A-S-H gels. There are no strict boundaries among these four basic stages, and they proceed crossing each other. Moreover, the leaching toxicity tests were also performed to prove that the developed red mud-coal gangue based cementitious materials are environmentally acceptable. PMID:27131457

  4. In Situ IR Characterization of CO Interacting with Rh Nanoparticles Obtained by Calcination and Reduction of Hydrotalcite-Type Precursors

    Directory of Open Access Journals (Sweden)

    F. Basile

    2011-01-01

    Full Text Available Supported Rh nanoparticles obtained by reduction in hydrogen of severely calcined Rh/Mg/Al hydrotalcite-type (HT phases have been characterized by FT-IR spectroscopy of adsorbed CO [both at room temperature (r.t. and nominal liquid nitrogen temperature] and Transmission Electron Microscopy (TEM. The effect of reducing temperature has been investigated, showing that Rh crystal size increases from 1.4 nm to 1.8 nm when the reduction temperature increases from 750°C to 950°C. The crystal growth favours the formation of bridged CO species and linear monocarbonyl species with respect to gem-dicarbonyl species; when CO adsorbs at r.t., CO disproportionation occurs on Rh and it accompanies the formation of RhI(CO2. The role of interlayer anions in the HT precursors to affect the properties of the final materials has been also investigated considering samples prepared from silicate-instead of carbonate-containing precursors. In this case, formation of RhI(CO2 and CO disproportionation do not occur, and this evidence is discussed in terms of support effect.

  5. Simultaneous Adsorption of Chromium (VI) and Phosphate by Calcined Mg-Al-CO{sub 3} Layered Double Hydroxides

    Energy Technology Data Exchange (ETDEWEB)

    Song, Xiulan; Wu, Yuhong [Taiyuan Univ. of Technology, Shanxi (China)

    2014-06-15

    The adsorption characteristics of chromium (VI) and phosphate on calcined Mg-Al-CO{sub 3} layered double hydroxides (CLDH) were investigated in single and binary systems. A series of batch experiments were performed to study the influence of various experimental parameters. In this study, CLDH exhibited a high adsorption capacity for Cr (VI) and P in a single system. The experimental data were close to the theoretical adsorption capacity given by the Langmuir isotherm, the calculating adsorption capacities of Cr (VI) and P were up to 70.42 mg/g and 97.09 mg/g, respectively. It was found that the initial pH was approximately 6 and it took 24 h to reach equilibrium when P and Cr (VI) were added simultaneously. The experimental data were best fitted by a pseudo-second-order kinetics model. Competitive adsorption between Cr (VI) and P existed in the binary system. The presence of Cr (VI) had no significant influence on P adsorption. However, the suppression of Cr (VI) adsorption was obvious when the initial concentration of P was up to 10 mg/L with a concentration of 0.5 g/L of CLDH.

  6. 全氟物改性煅白的防吸湿机理%Anti-moisture mechanism of calcined dolomite modified by perfluoroalkylethyl acrylate

    Institute of Scientific and Technical Information of China (English)

    梁晓波; 李明照; 王国卫; 梁一然; 张耀斌; 毛嘉; 任川兮

    2015-01-01

    对煅白表面锚固偶氮二氰基戊酸引发全氟烷基乙基丙烯酸酯(FM)聚合而制备的防吸湿煅白进行研究,利用 XPS、IR、DSC、TG、SEM 物理吸收和接触角测量等方法对改性前后煅白的结构、比表面积、形貌和疏水接触角等进行表征,并分析改性后煅白吸湿性降低的原因和机理。结果表明:煅白表面发生了偶联、锚固及聚合反应。锚固引发剂的煅白引发FM原位分散聚合而制得防吸湿煅白,其吸湿率随FM质量分数的增加而降低,当FM质量分数达到7%时,吸湿率不再下降,改性后煅白1 h的吸湿率由1.39%下降到0.017%;聚全氟烷基乙基丙烯酸酯(PFM)的接枝率为0.5%、接枝效率为26.6%,煅白表面出现一层连续而完整的全氟聚合物膜,其厚度约为8 nm。%4,4'-Azobis(4-cyanovaleric acid) (ACPA) was anchored onto the surface of calcined dolomite and radical graft polymerization of perfluoroalkylethyl acrylate (FM) from the modified calcined dolomite through dispersion polymerization were investigated. The structure, specific surface area, morphology and hydrophobic contact angle of calcined dolomite surface were characterised by XPS, IR, DSC, TG, SEM, physical absorption and contact angle measurement, and the reason and mechanism on the decreasing the moisture absorption rate of calcined dolomite after the modification were studied. The results show that the coupling, anchoring and polymerization reactions happen on the surface of calcined dolomite. Poly (Perfluoroalkylethyl acrylate) (PFM) is effectively grafted onto calcined dolomite through the initiation of anchored ACPA during in-situ dispersion polymerization. It shows that the moisture absorption rate of calcined dolomite decreases with increasing of the mass fraction of FM. When the mass fraction of FM is 7%, The moisture absorption rate decreases from 1.39% to 0.017% after modification for 1 h. The grafting rate and efficiency of PFA are 0.5% and

  7. An Overview of Project Planning for Hot-Isostatic Pressure Treatment of High-Level Waste Calcine for the Idaho Cleanup Project - 12289

    International Nuclear Information System (INIS)

    The Calcine Disposition Project is responsible for retrieval, treatment by hot-isostatic pressure, packaging, and disposal of highly radioactive calcine stored at the Idaho Nuclear Technology and Engineering Center at the Idaho National Laboratory Site in southeast Idaho. In the 2009 Amended Record of Decision: Idaho High-Level Waste and Facilities Disposition Final Environmental Impact Statement the Department of Energy documented the selection of hot-isostatic pressure as the technology to treat the calcine. The Record of Decision specifies that the treatment results in a volume-reduced, monolithic waste form suitable for transport outside of Idaho by a target date of December 31, 2035. That target date is specified in the 1995 Idaho Settlement Agreement to treat and prepare the calcine for transport out of Idaho in exchange for allowing storage of Navy spent nuclear fuel at the INL Site. The project is completing the design of the calcine-treatment process and facility to comply with Record of Decision, Settlement Agreement, Idaho Department of Environmental Quality, and Department of Energy requirements. A systems engineering approach is being used to define the project mission and requirements, manage risks, and establish the safety basis for decision making in compliance with DOE O 413.3B, 'Program and Project Management for the Acquisition of Capital Assets'. The approach draws heavily on 'design-for-quality' tools to systematically add quality, predict design reliability, and manage variation in the earliest possible stages of design when it is most efficient. Use of these tools provides a standardized basis for interfacing systems to interact across system boundaries and promotes system integration on a facility-wide basis. A mass and energy model was developed to assist in the design of process equipment, determine material-flow parameters, and estimate process emissions. Data generated from failure modes and effects analysis and reliability, availability

  8. 阴极炭块用电煅煤标准解析%Analysis for standard of electrically calcined anthracite for cathode blocks

    Institute of Scientific and Technical Information of China (English)

    曹培峰; 经云

    2014-01-01

    介绍了阴极炭块用电煅煤行业标准的起草过程,对标准中灰分、电阻率、真密度等指标进行了解释,对未列入标准的电煅煤固定碳含量、硫含量,电煅煤的强度等指标做了说明。%The drafting process of standard for the electrically calcined anthracite for cathode blocks was introduced. The explaina-tion for the indexes in the standard, such as the ash content, specific resistance, true density was made, and the indexes not unlisted in the standard, including the fixed carbon content, sulfur content and the intensity of the electrically calcined anthracite were also illustrated.

  9. Characterization of the Calcination Products of the Precipitates Obtained from the Bio-Oxidation with Thiobacillus Ferrooxidans of Sulphuric Water Pickling Liquors

    Science.gov (United States)

    Marco, J. F.; Gancedo, J. R.; López, F. A.

    1998-12-01

    The characterization of the calcination products of the precipitates obtained from the bio-oxidation with Thiobacillus ferrooxidans of sulphuric water pickling liquors has been carried out by means of Mössbauer spectroscopy, x-ray powder diffraction, infrared spectroscopy and transmission electron microscopy. The results show that a full transformation of the precipitates into α-Fe2O3 is achieved at temperatures higher than 850°C. Calcination at 700°C during two hours results in the formation of α-Fe2O3, ζ-Fe2O3 and Fe12O3(SO4)15. The Mössbauer parameters of ζ-Fe2O3 and Fe12O3(SO4)15 at 298 and 17K are reported.

  10. Effect of temperature and residence time of calcination phosphate on the chemical reactivity: Application to the case of Bouchane phosphate (Morocco

    Directory of Open Access Journals (Sweden)

    El Mokhtar El Ouardi

    2013-10-01

    Full Text Available The calcination of phosphate consumes the fossil energy and generates greenhouse gas emissions. This later owed not only on the consumption of these energies, but also in the decomposition of carbonates and in the combustion of the organic matter. The energy consumption and the emission of gases require an optimization of the calcination depending on the residence time and temperature of calcination. These walking parameters influence the chemical reactivity and the solubility of finished product. To assist in that, we have studied the evolution of the main components of the control in the calcination (Corg, CO2, P2O5, CaO, the specific surface area and density of the ore according to the time and temperature. This treatment was performed in the laboratory in a fixed bed. The different analytical techniques that were applied are: sieve analysis, quantitative study by ICP, the mineralogical characterization by X-ray and differential thermal analysis coupled with thermogravimetric analysis. The obtained results show that mechanisms relative to the heat treatment of the phosphate are multiple and are strongly influenced by the nature of the matrix and the parameters of the treatment. The obtained product answers well the trade profiles and the requirements for use under the conditions of a temperature approximately of 800°C and a period of 30 minutes. In these conditions, we note a decrease of 89.29% organic carbon and carbon dioxide of 72.72% with the increase in weight of Bone Phosphate Lime to 12.63%. However, the chemical reactivity and the solubility are affected.

  11. Comparative study of phase transition and textural changes upon calcination of two commercial titania samples: A pure anatase and a mixed anatase-rutile

    Science.gov (United States)

    Kordouli, Eleana; Dracopoulos, Vassileios; Vaimakis, Tiverios; Bourikas, Kyriakos; Lycourghiotis, Alexis; Kordulis, Christos

    2015-12-01

    The effect of calcination temperature and time on structural and textural changes of two commercial TiO2 samples (pure anatase and a mixture of anatase and rutile) has been investigated using N2 physisorption, ex-situ and in-situ X-ray powder diffraction, differential scanning calorimetry and UV-vis diffuse reflectance spectroscopy. The increase of the calcination temperature (up to 700 °C) and time (up to 8 h) causes only textural changes in the pure anatase, whereas a transformation of the anatase to rutile takes place, in addition, in the mixed titania (containing anatase and rutile). The textural changes observed in pure anatase sample were attributed to solid state diffusion leading to an increase in the size of anatase nanocrystals, through sintering. Thus, the mean pore diameter shifts to higher values and the pore volume and specific surface area decrease. The successful application of the Johnson-Mehl-Avrami-Kolmogorov model in the kinetic data concerning the pure anatase indicates a mass transfer control of sintering process. Similar textural changes were also observed upon calcination of the sample containing anatase and rutile. In this case not only sintering but the anatase to rutile transformation contributes also to the textural changes. Kinetic analysis showed that the rutile nanocrystals in the mixed titania served as seed for by-passing the high energy barrier nucleation step allowing/facilitating thus the anatase to rutile transformation. A fine control of the anatase to rutile ratio and thus of energy-gap and the population of hetero-junctions may be obtained by adjusting the calcination temperature and time.

  12. ICPP calcined solids storage facility closure study. Volume II: Cost estimates, planning schedules, yearly cost flowcharts, and life-cycle cost estimates

    International Nuclear Information System (INIS)

    This document contains Volume II of the Closure Study for the Idaho Chemical Processing Plant Calcined Solids Storage Facility. This volume contains draft information on cost estimates, planning schedules, yearly cost flowcharts, and life-cycle costs for the four options described in Volume I: (1) Risk-Based Clean Closure; NRC Class C fill, (2) Risk-Based Clean Closure; Clean fill, (3) Closure to landfill Standards; NRC Class C fill, and (4) Closure to Landfill Standards; Clean fill

  13. Studies on characterization, microstructures and magnetic properties of nano-size barium hexa-ferrite prepared through a hydrothermal precipitation-calcination route

    International Nuclear Information System (INIS)

    An attempt was made to prepare nano-size barium hexa-ferrite particles following a hydrothermal precipitation-calcination route using barium and iron nitrate solutions. During hydrothermal treatment at 180 deg. C (2 h precipitation time) barium carbonate and hematite phases were formed. This precursor was calcined at 800, 1000 and 1200 deg. C to determine the conditions for obtaining barium hexa-ferrite. The characterization studies on calcined products revealed that up to 800 deg. C, the major crystalline phases (barium carbonate and hematite) of the precursor were retained. At 1000 deg. C, formation of barium hexa-ferrite started and at 1200 deg. C, though most of the major peaks of X-ray diffractogram corresponded to barium hexa-ferrite, a number of peaks corresponding to hematite were also present. Some low intensity peaks for barium carbonate were observed. The average particle size was 40 nm. Saturation magnetization, remanence magnetization and coercivity were found to be 40.0, 21.6 emu g-1 and 2.87 kOe, respectively. The values obtained both for coercivity and magnetization for the present sample were lower than the reported bulk values which could be due to the fact that the sample prepared through the present technique was not mono-phasic

  14. Effect of calcination temperature and pretreatment with reaction gas on properties of Co/γ-Al2O3 catalysts for partial oxidation of methane.

    Science.gov (United States)

    Zhang, Nuo-Wei; Huang, Chuan-Jing; Zhu, Xiao-Quan; Xu, Jing-Dong; Weng, Wei-Zheng; Wan, Hui-Lin

    2012-08-01

    The effects of calcination temperature and feedstock pretreatment on the catalytic performance of Co/γ-Al(2)O(3) catalysts were studied for partial oxidation of methane (POM) to synthesis gas, with emphasis on the role of feedstock pretreatment. The physicochemical properties of the catalysts were characterized by N(2) adsorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), H(2) temperature-programmed reduction (H(2) -TPR), and Raman spectroscopy. The results showed that the pretreatment of the catalyst by reaction gas significantly improved the catalytic activity and stability for the POM reaction. On the other hand, the effect of calcination temperature was less significant. Although the initial activity was increased by an increased calcination temperature, the catalyst without the feedstock pretreatment suffered a rapid deactivation. The reaction-atmosphere pretreatment was revealed as a process that mainly modified the surface structure of the catalyst. In that process, the formation of a CoAl(2)O(4) -like compound led to high Co metal dispersion after reduction, and the transformation of the carrier into α-Al(2)O(3) occurred over the catalyst surface. Both the high dispersion of cobalt and the presence of α-Al(2)O(3) surface phase were assumed as the important factors resulting in an excellent catalytic performance in terms of high activity and high stability. PMID:22588989

  15. Effect of calcination temperature on the synthesis of potassium titanate with platy morphology; Efeito da temperatura de calcinacao na sintese de titanato de potassio com morfologia de placas

    Energy Technology Data Exchange (ETDEWEB)

    Farina, R., E-mail: ricardofarina@gmail.com [Universidade Federal de Sao Paulo (UNIFESP), Diadema, SP (Brazil); Fredericci, C. [Instituto de Pesquisas Tecnologicas (IPT), SP (Brazil); Yoshimura, H.N. [Universidade Federal do ABC (CECS/UFABC), SP (Brazil). Centro de Engenharia, Modelagem e Ciencias Sociais Aplicadas

    2011-07-01

    The dramatic increases in the number of pneumoconiosis cases have stimulated the search of new materials for replacement of asbestos fibers. Titanate plates with formula A{sub y}Ti{sub 2-x}M{sub x}O{sub 4}, where A = K, Rb, Cs and M = Li, Mg, Co, Ni, Cu, Zn, Mn (III), Fe (III) have been studied as an alternative for the use of fibers. The effect of the variation of calcination temperature on the reaction of K{sub 2}CO{sub 3}-TiO{sub 2}-Mg(OH){sub 2} system was studied with the aim of understanding the relationship of this parameter with the morphology and symmetry of the obtained plates. For this study the samples were calcined for 5 hours at temperatures of 950°C, 1000°C, 1050°C and 1100°C. The powders were analyzed by X-ray diffraction and scanning electron microscopy. It was concluded that 1000°C is the better calcination temperature for obtaining more symmetric plates with smaller particle size dispersion. (author)

  16. Effect of calcination temperature on the crystallite growth of cerium oxide nano-powders prepared by the co-precipitation process

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jian-Chih [Department of Orthopaedics, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan (China); Chen, Wen-Cheng [School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China); Tien, Yin-Chun [Department of Orthopaedics, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan (China); Shih, Chi-Jen, E-mail: cjshih@kmu.edu.t [Department of Fragrance and Cosmetics Science, Kaohsiung Medical University, 100 Shi-Chuan1st Road, Kaohsiung 80708, Taiwan (China)

    2010-04-30

    Cerium oxide nanocrystallites were synthesized by a co-precipitation process at a relatively low temperature, using cerium (III) nitrate as the starting material in a water solution with pH in the range of 8-9. The effect of calcination temperature on the crystallite growth of cerium oxide nano-powders was investigated by X-ray diffraction, transmission electron microscopy and electron diffraction. The crystallization temperature of the cerium oxide powders was estimated to be about 273 K, by XRD analysis. When calcined at temperatures from 473 to 1273 K, face-centered cubic phase crystallization was observed by XRD. The crystallite size of the cerium oxide increased from 12.0 to 48 nm as the calcining temperature increased from 473 to 1273 K, in the pH range 8-9. The activation energy for the growth of cerium oxide nanoparticles was found to have very low values of 17.5 kJ/mol for pH = 8 and 16.0 kJ/mol for pH = 9.

  17. Effect of calcination temperature on the crystallite growth of cerium oxide nano-powders prepared by the co-precipitation process

    International Nuclear Information System (INIS)

    Cerium oxide nanocrystallites were synthesized by a co-precipitation process at a relatively low temperature, using cerium (III) nitrate as the starting material in a water solution with pH in the range of 8-9. The effect of calcination temperature on the crystallite growth of cerium oxide nano-powders was investigated by X-ray diffraction, transmission electron microscopy and electron diffraction. The crystallization temperature of the cerium oxide powders was estimated to be about 273 K, by XRD analysis. When calcined at temperatures from 473 to 1273 K, face-centered cubic phase crystallization was observed by XRD. The crystallite size of the cerium oxide increased from 12.0 to 48 nm as the calcining temperature increased from 473 to 1273 K, in the pH range 8-9. The activation energy for the growth of cerium oxide nanoparticles was found to have very low values of 17.5 kJ/mol for pH = 8 and 16.0 kJ/mol for pH = 9.

  18. Effect of calcination temperature on structural properties and catalytic activity in oxidation reactions of LaNiO3 perovskite prepared by Pechini method

    Institute of Scientific and Technical Information of China (English)

    K.Rida; M.A.Pe(n)a; E.Sastre; A.Martínez-Arias

    2012-01-01

    The study presented the preparation of the perovskite oxide LaNiO3 by the complex citrate method,paying particular attention to evolution of its formation from the amorphous precursor with varied calcination temperatures.The products obtained after heat treatment under air between 200 and 800 ℃ were characterized by X-ray diffraction (XRD),thermogravimetric and differential thermal analysis (TG-DTA),Fourier transform infrared spectroscopy (FTIR),SBET measurements and X-ray photoelectron spectroscopy (XPS).The results showed the formation of a single phase with perovskite structure from ca.550 ℃.Tests on the two catalytic oxidation reactions of C3H6 and CO over the system calcined between mentioned temperatures were examined on the basis of characterization results and showed that optimum catalytic properties for such reactions were achieved for the perovskite calcined at 600 ℃.In turn,correlations between redox and catalytic properties were established on the basis of thermogravimetric temperature programmed reduction (TPR) analysis.

  19. Performance of Cobalt-Based Fischer-Tropsch Synthesis Catalysts Using Dielectric-Barrier Discharge Plasma as an Alternative to Thermal Calcination%Performance of Cobalt-Based Fischer-Tropsch Synthesis Catalysts Using Dielectric-Barrier Discharge Plasma as an Alternative to Thermal Calcination

    Institute of Scientific and Technical Information of China (English)

    白素丽; 黄承都; 吕静; 李振花

    2012-01-01

    Co-based catalysts were prepared by using dielectric-barrier discharge (DBD) plasma as an alternative method to conventional thermal calcination. The characterization results of N2-physisorption, temperature programmed reduction (TPR), transmission electron microscope (TEM), and X-ray diffraction (XRD) indicated that the catalysts prepared by DBD plasma had a higher specific surface area, lower reduction temperature, smaller particle size and higher cobalt dispersion as compared to calcined catalysts. The DBD plasma method can prevent the sintering and aggregation of active particles on the support due to the decreased treatment time (0.5 h) at lower temperature compared to the longer thermal calcination at higher temperature (at 500~C for 5 h). As a result, the catalytic performance of the Fischer-Tropsch synthesis on DBD plasma treated Co/Si02 catalyst showed an enhanced activity, C5+ selectivity and catalytic stability as compared to the conventional thermal calcined Co/SiO2 catalyst.

  20. Effect of calcination temperature on electrocatalytic activities of Ti/IrO2 electrodes in methanol aqueous solutions

    International Nuclear Information System (INIS)

    The electrochemical activity of thermo-decomposed Ti/IrO2 electrodes in aqueous solution containing methanol compound has been studied, emphasizing on the influence of calcination temperature. Scanning electron microscopy (SEM) images showed that the typical cracked morphology of oxide coatings disappears gradually as the preparation temperature increases, leading to the decrease in the amount of electrochemically active sites as measured by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in organics-free aqueous solution. With the exception of samples prepared at high temperatures (e.g. 600 deg. C), same change tendency of electro-activity with temperature was also found in methanol aqueous solutions, in which activity was observed to decrease as compared with that in blank solution. Three possible explanations for this phenomenon (i.e. active dissolution of oxide coatings, organics adsorption and dimerization/polymerization on electrode surface, respectively) were discussed, where the former two were believed to be more reasonable considering the CH3OH small molecular chosen in this system. However, none of these three mechanisms could explain the abnormal activation behavior observed at electrodes prepared at 600 deg. C in CH3OH solution. XRD pattern showed the fact that when sintering temperature went up to 600 deg. C IrO2 would decompose into metallic iridium component. The existence of metallic iridium might facilitate the organics oxidation as stated in previous literatures, which leads to the exceptional activation of oxide surface by methanol component. A simple reaction mechanism for electrodes in methanol aqueous solutions was proposed and used to interpret the negative shift in startness potential of the oxygen evolution reaction (OER). Organics oxidation seems to facilitate the OER and vice versa. The latter statement has been reported by other workers

  1. Competitive adsorption characteristics of fluoride and phosphate on calcined Mg-Al-CO{sub 3} layered double hydroxides

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Peng [School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Zheng, Hong, E-mail: zhengh@cugb.edu.cn [School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Wang, Chong; Ma, Hongwen; Hu, Jianchao; Pu, Yubing; Liang, Peng [School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China)

    2012-04-30

    Highlights: Black-Right-Pointing-Pointer The influences of pH, contact time and order of addition of the anions were obtained. Black-Right-Pointing-Pointer The kinetic data were found to fit very well the pseudo second-order kinetic model. Black-Right-Pointing-Pointer Data of equilibrium experiments were fitted well to Langmuir isotherm. Black-Right-Pointing-Pointer The competitive monolayer adsorption capacities obviously decreased. Black-Right-Pointing-Pointer ATR-FTIR proofs of competitive adsorption were obtained. - Abstract: With synthetic wastewater, competitive adsorption characteristics of fluoride and phosphate on calcined Mg-Al-CO{sub 3} layered double hydroxides (CLDH) were investigated. A series of batch experiments were performed to study the influence of various experimental parameters, such as pH, contact time, and order of addition of the anions on the competitive adsorption of fluoride and phosphate on CLDH. It was found that the optimal pH is around 6 and it took 24 h to attain equilibrium when fluoride and phosphate were simultaneous added. The order of addition of anions influenced the adsorption of fluoride and phosphate on CLDH. The kinetic data were analyzed using the pseudo first-order and pseudo second-order models and they were found to fit very well the pseudo second-order kinetic model. Data of equilibrium experiments were fitted well to Langmuir isotherm and the competitive monolayer adsorption capacities of fluoride and phosphate were found to be obviously lower than those of single anion at 25 Degree-Sign C. The results of X-ray diffraction, Scanning Electron Microscopy with energy-dispersive X-ray analyses, and ATR-FTIR demonstrate that the adsorption mechanism involves the rehydration of mixed metal oxides and concomitant intercalation of fluoride and phosphate ions into the interlayer to reconstruct the initial LDHs structure.

  2. Role of Mg{sub x}Ca{sub 1−x}CO{sub 3} on the physical–chemical properties and cyclic CO{sub 2} capture performance of dolomite by two-step calcination

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ke; Han, Dongtai, E-mail: handongtai@cumt.edu.cn; Zhao, Pengfei, E-mail: zhaopfcumt@163.com; Hu, Xiumeng; Yin, Zeguang; Wu, Di

    2015-08-20

    Highlights: • Two-step calcination treated dolomite sorbent was prepared and characterized. • An intermediate phase (Mg{sub x}Ca{sub 1−x}CO{sub 3}) was observed by TG and XRD results. • Mg-calcite hindered the de-mixing of Ca and Mg. • Smaller grains, larger specific surface area and pore volume were obtained. • This favorable structure resulted in a high and stable CO{sub 2} capture performance. - Abstract: Two-step calcination (CO{sub 2} and N{sub 2} atmospheres) was used to modify the microstructure of natural dolomite for high-temperature CO{sub 2} capture. Two other one-step calcinations (CO{sub 2} or N{sub 2} atmosphere) were provided for comparison. Different morphological characterizations (thermal decomposition, phase composition, morphology, and nitrogen adsorption) were performed, followed by an analysis of 30 carbonation/calcination cycles in a fixed bed reactor. During primary calcination in a CO{sub 2} atmosphere, an intermediate phase (Mg{sub x}Ca{sub 1−x}CO{sub 3}) was observed by TG and XRD results, which hindered the de-mixing of CaO and MgO in the secondary calcination in a N{sub 2} atmosphere. Therefore, two-step calcination produced smaller grains (CaO: 45.2 nm; MgO: 32.6 nm), larger specific surface area (21.08 m{sup 2}/g) and pore volume (0.082 cm{sup 3}/g) and uniform distribution of CaO and MgO, which resulted in a higher and more stable uptake of CO{sub 2} compared to the results from one-step calcinations.

  3. Influence of calcination temperature on Cd{sub 0.3}Co{sub 0.7}Fe{sub 2}O{sub 4} nanoparticles: Structural, thermal and magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, Ch.Venkata, E-mail: cvrphy@gmail.com [School of Mechanical Engineering, Yeungnam University, 214-1, Dae-dong, Gyeongsan-si, Gyeongsangbuk-do 712-749 (Korea, Republic of); PrabhakarVattikuti, S.V. [School of Mechanical Engineering, Yeungnam University, 214-1, Dae-dong, Gyeongsan-si, Gyeongsangbuk-do 712-749 (Korea, Republic of); Ravikumar, R.V.S.S.N. [Department of Physics, Acharya Nagarjuna University, AP 522510 (India); Moon, Sang Jun, E-mail: nanobiomems@dgist.ac.kr [Cybernetics Laboratory, Daegu Gyeongbuk Institute of Science and Technology (DGIST) (Korea, Republic of); Shim, Jaesool, E-mail: jshim@ynu.ac.kr [School of Mechanical Engineering, Yeungnam University, 214-1, Dae-dong, Gyeongsan-si, Gyeongsangbuk-do 712-749 (Korea, Republic of)

    2015-11-15

    Cadmium substituted cobalt ferrite nanoparticles are synthesis using the chemical method. The as-prepared ferrite nanoparticles are calcinated at 300 °C and 600 °C respectively. The samples are studied using; Powder XRD, SEM with EDX, TEM, FT-IR, TG-DTA and vibrating sample magnetometer (VSM) in order to study the calcination temperature effect on structural, morphological and magnetic properties. The magnetic properties, like saturation magnetization and coercivity increases with increasing the calcination temperature. This enhancement is attributed to the transition from amulti-domain to a single-domain nature. The absorption bands observed at 588 cm{sup −1} (ν{sub 1}) and 440 cm{sup −1} (ν{sub 2}) are attributed to the vibrations of tetrahedral and octahedral complexes. The TG-DTA curves reveal the thermal stability of the prepared ferrite nanoparticles. The calcination temperature influences the magnetic properties, surface morphology and crystalline size. - Highlights: • Cd{sub 0.3}Co{sub 0.7}Fe{sub 2}O{sub 4} nanoparticles synthesized using the chemical co-precipitation. • The magnetization, coercivity values increases with increasing the calcination temperature. • The calcination temperature influences the magnetic properties and crystallite size. • The FTIR spectra results confirmed the vibrations of tetrahedral and octahedral complexes.

  4. 固定床煅烧炉中载铯亚铁氰化钛钾的热分解研究%Thermal Decomposition of Potassium Titanium Hexacyanoferrate (Ⅱ) Loaded with Cesium in a Fixed Bed Calciner

    Institute of Scientific and Technical Information of China (English)

    冯孝贵; 景山; 吴秋林; 陈靖; 宋崇立

    2007-01-01

    The thermal decomposition of potassium titanium hexacyanoferrate(Ⅱ) (KTiFC) loaded with cesium (referred to as Used Exchanget,or UE) was studied at different flow rate of air in a fixed bed calciner.The calcination process consisted of four stages:ambient temperature-180℃ (stage Ⅰ),180-250℃ (stage Ⅱ),250-400℃ (stage Ⅲ),and constant 400℃ (stage Ⅳ).The most intense reaction occurred in stage Ⅱ.The rate of thermal decomposition was controlled,depending on the O2 flux,by O2 or CN concentration in different stages.Results from differential thermal analysis (DTA) showed that the calcination reaction of the anhydrous UE was exotlaemic, with an approximate heat output of 4.6kJ·g-1,which was so large to cause the possible agglomeration of calcined residues.The agglomeration could be avoided by enhancing heat transfer and controlling the O2 flux.It was found that there was no cyanides in the calcined residues and no CN-bearing gases such as HCN and (CN)2 in the off-gas.It seemed that the catalytic oxidation furnace behind the fixed bed calciner could be cancelled.

  5. Rheology and zeta potential of cement pastes containing calcined silt and ground granulated blast-furnace slag

    Directory of Open Access Journals (Sweden)

    Safi, B.

    2011-09-01

    Full Text Available This study aimed to analyse the re-use of dam silt as a supplementary binder for self-compacting concrete (SCC. When burnt, silt becomes more reactive because the kaolin it contains is converted into metakaolin. Portland cement, calcined or burnt silt and ground granulated blast furnace slag were used in this research. Cement pastes were prepared with blends containing two or three of these materials. The replacement ratio for burnt silt in both cases was 10 % and 20 % by cement weight and the ratio for the slag was a constant 30 % by weight of the blend. Rheological and zeta potential tests were conducted to evaluate paste electrokinetics and rheological behaviour. The findings showed that burnt silt is apt for use as an addition to cement for SCC manufacture.

    En el presente trabajo se ha analizado la posibilidad de utilizar los lodos procedentes de embalses como adición en la fabricación del hormigón autocompactante (HAC. Con la calcinación, estos materiales se vuelven más reactivos debido a la transformación en metacaolín, del caolín que forma parte de su composición. Las materias primas empleadas en esta investigación son: cemento Pórtland, lodos de embalse calcinados y escorias granuladas de horno alto. Se prepararon pastas de cemento con mezclas que contenían dos o tres de estos materiales. El porcentaje de reemplazo de los lodos calcinados osciló entre el 10 y el 20 % en peso del cemento, mientras que el de la escoria fue del 30 % en peso de la mezcla. Se llevaron a cabo ensayos reológicos y de potencial zeta para evaluar el comportamiento electrocinético y reológico de las distintas pastas. De acuerdo con los resultados obtenidos, una vez calcinados, los lodos de embalse son aprovechables como adición al cemento con destino a la preparación de HAC.

  6. EFFECT OF DRYING AND CALCINATION TEMPERATURE ON HYDROCRACKING CATALYST%干燥及焙烧温度对加氢裂化催化剂的影响

    Institute of Scientific and Technical Information of China (English)

    樊宏飞; 孙晓艳; 崔国旗; 蔡天锡

    2012-01-01

    采用浸渍法在不同干燥和焙烧温度下制备一系列WNi型加氢裂化催化剂,采用N2-物理吸附、NH3-TPD、XRD、TPR等手段对催化剂进行表征,并用十二烷为模型化合物考察催化剂的加氢裂化性能.结果表明:随着焙烧温度的升高,催化剂的比表面积略有降低,孔径变大,孔体积变化不大;随着焙烧温度的升高,催化剂的酸量呈先增加后降低的变化趋势,在400℃时达到最大值,当焙烧温度提高到600℃时,金属组分在载体表面发生聚集;加氢裂化催化剂的活性随着焙烧温度的升高呈先增加后降低的变化趋势,峰值出现在焙烧温度为500℃处.说明适宜的焙烧温度有利于提高催化剂的催化性能,当催化剂经过高温焙烧时,会对其活性产生抑制作用.干燥温度由200℃降到120℃时,催化剂的孔体积和孔径提高,比表面积略有降低,酸量基本不变,催化活性提高.%A series of W/Ni-based hydrocracking catalysts dried and calcined under various temperatures was prepared by impregnation method. The prepared catalysts were characterized by means of N2-adsorption,NH3-TPD,XRD and TPR technique; the hydrocracking performance of these catalysts was investigated using dodecane as model compound. The results showed that with the increase of calcination temperature,the specific surface area of the catalyst decreased slightly,pore size increased and pore volume was basically unchanged. The acid amount and hydrocracking activity of the catalyst both showed a tendency to ascend firstly,followed to descend with the increase of calcination temperature,and the peak value for the former and the latter was at 400 ℃ and 500 ℃ respectively. When the calcination temperature reached 600 ℃ ,aggregation of the metal components happened on the surface of the carrier. On the whole,catalyst calcined under suitable temperature could improve its performance,yet high temperature calcination might suppress the activity of

  7. 煅烧高岭土的比表面积与吸油性能%Specific Surface Area and Oil Adsorption of Calcinated Kaolin Clay

    Institute of Scientific and Technical Information of China (English)

    孙涛; 陈洁渝; 周春宇; 雷新荣

    2013-01-01

    A washed kaolin clay was calcinated in the temperature range from 600 ℃ to 1 000 ℃. The microscopic morphology, the phase, the specific surface area and pore size distribution of the products were characterized by field emission scanning electron microscopy, X-ray diffraction and BET nitrogen adsorption measurement, respectively. The relationship between oil absorption and specific surface area was analyzed. The results show that the oil adsorption of calcinated kaolin clay with the smallest average pore size at 750 ℃ is the greatest (i.e., 80.272 g/100 g). The oil adsorption of calcinated kaolin clay became greater due to the larger specific surface area and the presence of the more concentrated micropore and mesopore in the pore distribution at the calcining temperature of < 800 ℃. The microporous occlusion of the kaolin clay occurred when calcinated at 800 ℃, causing the more concentrated mesopore and macropore in the pore distribution. As a result, the oil absorption reduced. The oil absorption of the calcinated kaolin clay was closely related to the specific surface area and the more concentrated micropore in the pore distribution.%以水洗高岭土为原料,在600~1 000℃,以50℃为间隔取点煅烧.通过场发射扫描电镜观察产品的微观形貌、X射线衍射仪分析产品的物相,并用BET物理吸附仪表征产品的比表面积和孔径分布,根据煅烧高岭土的微观形貌、物相组成、吸脱附等温线等,分析其比表面积与吸油性能的关系.结果表明:750℃的煅烧高岭土吸油值最高,为80.272 g/100g,此时煅烧高岭土的比表面积最大,孔径分布集中于微孔和中孔,平均孔径最小.煅烧温度低于800℃时,煅烧高岭土的孔径分布较集中于微孔和中孔,比表面积较大,吸油值较高;煅烧温度升高至800℃以后,高岭土发生烧结导致微孔闭塞,孔径分布向中孔和大孔集中,比表面积减小,吸油值较低.因而煅烧高岭土的吸油性

  8. Oxidative desulfurization of benzothiophene and thiophene with WO{sub x}/ZrO{sub 2} catalysts: Effect of calcination temperature of catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Hasan, Zubair; Jeon, Jaewoo [Department of Chemistry and Green-Nano Materials Research Center, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Jhung, Sung Hwa, E-mail: sung@knu.ac.kr [Department of Chemistry and Green-Nano Materials Research Center, Kyungpook National University, Daegu 702-701 (Korea, Republic of)

    2012-02-29

    Highlights: Black-Right-Pointing-Pointer Oxidative desulfurization was studied with WO{sub x}/ZrO{sub 2} calcined at different temp. Black-Right-Pointing-Pointer The importance of the phases of zirconia and tungsten oxide was suggested. Black-Right-Pointing-Pointer The catalyst was analyzed thoroughly with Raman and XRD techniques. Black-Right-Pointing-Pointer The importance of electron density on S was confirmed with the kinetics of oxidation. - Abstract: Oxidative desulfurization (ODS) of model fuel containing benzothiophene (BT) or thiophene (Th) has been carried out with WO{sub x}/ZrO{sub 2} catalyst, which was calcined at various temperatures. Based on the conversion of BT in the model fuel, it can be shown that the optimum calcination temperature of WO{sub x}/ZrO{sub 2} catalyst is around 700 Degree-Sign C. The most active catalyst is composed of tetragonal zirconia (ZrO{sub 2}) with well dispersed polyoxotungstate species and it is necessary to minimize the contents of the crystalline WO{sub 3} and monoclinic ZrO{sub 2} for a high BT conversion. The oxidation rate was interpreted with the first-order kinetics, and it demonstrated the importance of electron density since the kinetic constant for BT was higher than that for Th even though the BT is larger than Th in size. A WO{sub x}/ZrO{sub 2} catalyst, treated suitably, can be used as a reusable active catalyst in the ODS.

  9. Effect of Calcination Temperature on Structure and O2 Desorption Properties of CexPr1-xO2-δ Mixed Oxides

    Institute of Scientific and Technical Information of China (English)

    Yan Zonglan; Shi Jun; Bu Yafan; Zhao Pengying; Wang Zhan

    2007-01-01

    A series of CexPr1-xO2-δ (x=0,0.5,0.9,1.0) mixed oxide calcined at different temperatures were synthesized by sol-gel method and characterized by Raman, XRD and O2-TPD techniques. When x=0.9, only a cubic phase CeO2 is observed. When x=0.5, the compound was combined by Pr6O11 and CeO2 mixed oxides. For CexPr1-xO2-δ (x=0.5,0.9) samples 465cm-1 Raman peak is attributed to the Raman active F2g mode of Ceo2. The broad peak at about 570cm-1 can be linked to lattice defects resulting in oxygen vacancies. The crystallite size of the samples increased as increasing the calcined temperature. But the increased value of Ce0.9Pr0.1O2-δ and Ce0.5Pr0.5O2-δ is smaller than single CeO2 and Pr6O11 obviously. It reveals that the insertion of Pr atom into the ceria lattice could enhance the sintering resistance and thermal stability of the mixed oxides. Calcination temperatures had great effect on the peak intensity for CeO2 but less effect on Ce0.8Pr0.2O2-δ in Raman spectra, and it may be caused by the colors transformation of the mixed oxidfs. The result of O2-TPD experiment indicates that the formation of solid solution has elevation the stabilization and thermal stability of the mixed oxides.

  10. Hydrogen-Rich Gas Production by Sorption Enhanced Steam Reforming of Woodgas Containing TAR over a Commercial Ni Catalyst and Calcined Dolomite as CO2 Sorbent

    OpenAIRE

    Vincenzo Naso; Andrea Micangeli; Mario Sisinni; Enrico Bocci; Andrea Di Carlo

    2013-01-01

    The aim of this work was the evaluation of the catalytic steam reforming of a gaseous fuel obtained by steam biomass gasification to convert topping atmosphere residue (TAR) and CH4 and to produce pure H2 by means of a CO2 sorbent. This experimental work deals with the demonstration of the practical feasibility of such concepts, using a real woodgas obtained from fluidized bed steam gasification of hazelnut shells. This study evaluates the use of a commercial Ni catalyst and calcined dolomite...

  11. Hydrogen-Rich Gas Production by Sorption Enhanced Steam Reforming of Woodgas Containing TAR over a Commercial Ni Catalyst and Calcined Dolomite as CO 2 Sorbent

    OpenAIRE

    Mario Sisinni; Andrea Di Carlo; Enrico Bocci; Andrea Micangeli; Vincenzo Naso

    2013-01-01

    The aim of this work was the evaluation of the catalytic steam reforming of a gaseous fuel obtained by steam biomass gasification to convert topping atmosphere residue (TAR) and CH 4 and to produce pure H 2 by means of a CO 2 sorbent. This experimental work deals with the demonstration of the practical feasibility of such concepts, using a real woodgas obtained from fluidized bed steam gasification of hazelnut shells. This study evaluates the use of a commercial Ni catalyst and calcined dolom...

  12. The Influence of Calcined Clay Pozzolan, Low-Cao Steel Slag and Granite Dust On the Alkali-Silica Reaction in Concrete

    OpenAIRE

    James Sarfo-Ansah; Eugene Atiemo

    2015-01-01

    The influence of low CaO steel slag, calcined clay and granite dust on the alkali-silica reaction was investigated over a period of 35 days under accelerated curing conditions. The mineral admixtures were used to replace varying portions of high alkali Portland limestone cement up to an admixture content of 25% in order to study their effect on the alkali-silica reaction (ASR). Portland limestone cement used for the study had a total Na2Oeq of 4.32. XRD analysis of hydrated mortar...

  13. 煅烧工艺制度对轻烧白云石活性度的影响%Effect of calcining process and system on reactivity of soft-burnt dolomite

    Institute of Scientific and Technical Information of China (English)

    高华

    2012-01-01

    The effect of calcining processes on the reactivity three kinds of soft-burnt dolomites is studied through calcining test and observation of microstructure. It is concluded as follows : ( 1 ) soaking time is 90 minutes,, there is a trend in which the reactivity of soft-burnt dolomite is increased first with the calcining temperature uprising and then decreased. At 1 050℃ the reactivity of soft-burnt dolomite reaches the highest value; (2) for some calcining temperature, there is a period of calcining time to make soft-burnt lime have a highest reactivity value ; (3) the grain size of the dolomite tobe calcined has influence on the reactivity of the calcined product; (4) the microstructure of the raw dolomite has great influence on the reactivity of the calcined product, generally the raw dolomite with coarse and big crystals is easy to obtain the calcined product with higher reactivity.%通过煅烧实验和显微结构观察,研究了煅烧工艺对三种自云石轻烧后活性度的影响,得出如下结论:(1)保温时间为90min,随煅烧温度提高轻烧白云石的活性呈现先升高、后降低的趋势,在1050℃活性度达到最高点。(2)对应某煅烧温度存在一个煅烧时间使轻烧白云石活性最高。(3)白云石的煅烧颗粒尺寸影响煅烧产物活性度。(4)白云石原矿的显微结构对煅烧产物活性度有很大影响,一般晶粒粗大的原矿易得到活性较高的煅烧产物。

  14. Study on preparation of food grade sodium trimetaphosophate by multi-step calcination%分段煅烧法制备食品级三偏磷酸钠试验研究

    Institute of Scientific and Technical Information of China (English)

    李国生; 郭玲

    2016-01-01

    High purty food grade sodium trimetaphosophate was prepared by multi-step calcination from anhy-drous sodium dihydrogen phosphate. The optimal calcination method was determined by multi-step calcination ex-periment in different conditions,and the reaction mechanism of calcination was analyzed.It was found that high pur-ty food grade products can be prepared from sodium dihydrogen phosphate by the optimal calcination method, the content of sodium trimetaphosphate in products can reach more than 99.5%.%以无水NaH2PO4为原料,通过分段煅烧制备出了高纯度食品级Na3(PO3)3。通过设计在不同条件下的分段煅烧试验,确定了较优煅烧方法,并对其反应机理进行了分析。试验表明,以无水NaH2PO4为原料,采用较优煅烧方法可以制得高纯度食品级产品,产品中三偏磷酸钠的含量可达99.5%以上。

  15. Influence of Zn/Fe Molar Ratio on Optical and Magnetic Properties of ZnO and ZnFe2O4 Nanocrystal as Calcined Products of Layered Double Hydroxides

    Directory of Open Access Journals (Sweden)

    Abdullah Ahmed Ali Ahmed

    2014-01-01

    Full Text Available The coprecipitation method has been used to synthesize layered double hydroxide (Zn-Fe-LDH nanostructure at different Zn2+/Fe3+ molar ratios. The structural properties of samples were studied using powder X-ray diffraction (PXRD. LDH samples were calcined at 600°C to produce mixed oxides (ZnO and ZnFe2O4. The crystallite size of mixed oxide was found in the nanometer scale (18.1 nm for ZnFe2O4 and 43.3 nm for ZnO. The photocatalytic activity of the calcination products was investigated using ultraviolet-visible-near infrared (UV-VIS-NIR diffuse reflectance spectroscopy. The magnetic properties of calcined LDHs were investigated using a vibrating sample magnetometer (VSM. The calcined samples showed a paramagnetic behavior for all Zn2+/Fe3+ molar ratios. The effect of molar ratio on magnetic susceptibility of the calcined samples was also studied.

  16. Spectroscopic properties of MgAl2-xO4:xCr3+ nanoparticles prepared by a high-temperature calcination method

    Science.gov (United States)

    Du, Xinhua; Tian, Hai; Yao, Shiyue; Long, Yumei; Liang, Bo; Li, Weifeng

    2015-12-01

    In this study, Cr3+-doped MgAl2O4 nanophosphors have been prepared via a facile high-temperature calcination route. The structure and morphology of the products were characterized by x-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM) techniques, which confirmed the typical spinel MgAl2O4 phase and sphere-like shape with particle size distribution of 50-80 nm. It was found that the Cr3+-doped MgAl2O4 can be efficiently excited by visible light and exhibits intense red emission peaking at 695 nm, corresponding to the 2Eg→4A2g transition of Cr3+ ions. The evolution of the luminescent properties on the Cr-doping concentration (0, 0.5, 1, 2, 3, 4 and 6 mol%) was then investigated and the optimal concentration was 3.0 mol%. It is believed that active intermediates and gases created in the calcining process play important roles not only on the formation of the monodispersed nanoparticles, but also on the homogeneous doping of Cr3+ at high concentration.

  17. Morphological Changes of Limestone Sorbent Particles during Carbonation/Calcination Looping Cycles in a Thermogravimetric Analyzer (TGA) and Reactivation with Steam

    KAUST Repository

    Wu, Y.

    2010-04-15

    Carbonation and calcination looping cycles were carried out on four limestones in a thermogravimetric analyzer (TGA). The CO2 carrying capacity of a limestone particle decays very quickly in the first 10 cycles, reducing to about 20% of its original uptake capacity after 10 cycles for the four limestones studied in this work, and it decreases further to 6-12% after 50 cycles. A new steam reactivation method was applied on the spent sorbent to recover the loss of reactivity. The steam reactivation of multi-cycled samples was conducted at atmospheric pressure. Steam reactivation for 5 min at 130 °C of particles that had undergone 10 cycles resulted in an immediate increase (by 45-60% points) in carrying capacity. The morphological changes of limestone particles during the cycling and steam reactivation were studied using both an optical microscope and scanning electron microscopy (SEM). The diameters of limestone particles shrank by about 2-7% after 10 carbonation/calcination cycles, and the particle diameters swelled significantly (12-22% increase) after steam reactivation. These size changes are important for studies of attrition and mathematical modeling of carbonation. © 2010 American Chemical Society.

  18. Synthesis of single- and double-walled carbon nanotubes using the calcined MgO supported commercial metal oxide as catalysts

    International Nuclear Information System (INIS)

    Simple, low-cost and environment-friendly catalysts for synthesizing carbon nanotubes were prepared by simply calcining the mixture of commercial transition metal oxide powders and porous or crystalline MgO at 950 °C. The commercial metal oxide powders, including Fe2O3, Co2O3, Ni2O3, Fe3O4 and Co3O4, were directly used without any pretreatment. Calcination of the MgO supported Fe2O3 catalysts results in the formation of MgFe2O4/MgO solid solution or the dissolution of metal into MgO lattices. High quality single- and double-walled carbon nanotubes were synthesized by thermal decomposition of methane, and were characterized by field emission scanning electron microscopy, high-resolution transmission electron microscopy, and Raman spectroscopy. The results bring forward an effective way to prepare the catalyst for synthesizing single- and double-walled carbon nanotubes. - Highlights: ► MgO supported catalysts for synthesizing carbon nanotubes were prepared. ► Commercial metal oxides were chosen as catalyst precursors. ► Single- and double-walled carbon nanotubes were synthesized.

  19. Synthesis of single- and double-walled carbon nanotubes using the calcined MgO supported commercial metal oxide as catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Mao-Lin; Jia, Yong, E-mail: yjiaahedu@163.com; Fang, Fang; Zhou, Shuang-Sheng; Wu, Pei-Yun; Peng, Dai-Yin

    2012-12-15

    Simple, low-cost and environment-friendly catalysts for synthesizing carbon nanotubes were prepared by simply calcining the mixture of commercial transition metal oxide powders and porous or crystalline MgO at 950 Degree-Sign C. The commercial metal oxide powders, including Fe{sub 2}O{sub 3}, Co{sub 2}O{sub 3}, Ni{sub 2}O{sub 3}, Fe{sub 3}O{sub 4} and Co{sub 3}O{sub 4,} were directly used without any pretreatment. Calcination of the MgO supported Fe{sub 2}O{sub 3} catalysts results in the formation of MgFe{sub 2}O{sub 4}/MgO solid solution or the dissolution of metal into MgO lattices. High quality single- and double-walled carbon nanotubes were synthesized by thermal decomposition of methane, and were characterized by field emission scanning electron microscopy, high-resolution transmission electron microscopy, and Raman spectroscopy. The results bring forward an effective way to prepare the catalyst for synthesizing single- and double-walled carbon nanotubes. - Highlights: Black-Right-Pointing-Pointer MgO supported catalysts for synthesizing carbon nanotubes were prepared. Black-Right-Pointing-Pointer Commercial metal oxides were chosen as catalyst precursors. Black-Right-Pointing-Pointer Single- and double-walled carbon nanotubes were synthesized.

  20. Study the effect of calcination temperature on physical and magnetic properties of bare Cobalt nanoparticles and that coated with silica shell

    International Nuclear Information System (INIS)

    In this paper, in order to investigate the effect of calcination temperature on the structural and magnetic properties of cobalt nanoparticles, samples have been prepared by Co-precipitation method at different calcination temperature. Cobalt nanoparticles have been prepared by Co-precipitation method at room temperature using hydrazine as reducing in ethanol hydrazine alkaline environment. This agent reduces cobalt salts to Cobalt nanoparticles in FCC and HCP phases. Phase analysis and investigation of Structural properties of the samples using X-ray diffraction patterns (XRD) confirm the formation of hexagonal phases of Co nanoparticles. Transmission electron microscopy was used for determining the size and shape morphology of nanoparticles. Magnetic properties of these nanoparticles have been investigated using a Vibrating sample magnetometer. The results indicate that these nanoparticles are ferromagnetic at room temperature. In addition, in this paper Co nanoparticles coated with silica shell have been prepared by the wet chemical method. Transmission electron microscopy images showed the cobalt core with average diameter of 17-20 nm coated by a silica shell with thickness of 5-7 nm. Hysteresis Loop of these Co nanoparticles coated by silica shell illustrates 16.9 emu/gr for saturation magnetization at 10000 (Oe), which is much less than that of Cobalt nanoparticles

  1. Investigation of the possibility of copper removal from industrial leachate by raw and calcined phosphogypsum: D-optimal and Taguchi designs

    Energy Technology Data Exchange (ETDEWEB)

    Mesci, Basak [Engineering Faculty, Department of Material Science and Engineering, Ondokuz Mayis University, Kurupelit, Samsun (Turkey); Turan, Nurdan Gamze [Engineering Faculty, Department of Environmental Engineering, Ondokuz Mayis University, Kurupelit, Samsun (Turkey); Ozgonenel, Okan [Engineering Faculty, Department of Electric and Electronic Engineering, Ondokuz Mayis University, Kurupelit, Samsun (Turkey)

    2012-08-15

    In the present study, the removal of Cu(II) was evaluated by raw and calcined phosphogypsum (PG) as an industrial product. The role of experimental factors on the removal of Cu(II) was examined by using D-optimal and Taguchi designs. The experimental factors and their related levels were selected as initial pH of 3-6-8, adsorbent content of 5, 10, and 25 g L{sup -1}, contact time of 5, 10, and 20 min, and temperature of 20, 40, and 60 C. The results are evaluated by ANOVA test to extract important experimental factors and their levels. The performances of the suggested factorial designs were then compared and regression models that took into account the significant main and interaction effects were suggested. Taguchi design was found as a reliable solution with less number of experiments for adsorption studies with the optimized values. The resultant removal efficiency is calculated as 78.34%. The results revealed that calcined PG is an appropriate adsorbent for Cu(II) removal from leachate of industrial waste. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. The Synergistic Effect of Nitrogen Dopant and Calcination Temperature on the Visible-Light-Induced Photoactivity of N-Doped TiO2

    Directory of Open Access Journals (Sweden)

    Yao-Tung Lin

    2013-01-01

    Full Text Available The synergistic effect of nitrogen content and calcinations temperature on the N-doped TiO2 catalysts prepared by sol-gel method was investigated. The phase and structure, chemical state, optical properties, and surface area/pore distribution of N-doped TiO2 were characterized using X-ray diffraction spectrometer, high-resolution transmission electron microscope, X-ray photoelectron spectroscopy, UV-vis diffusion reflectance spectroscopy, and Brunauer-Emmett-Teller specific surface area. Finding showed that the photocatalytic activity of N-doped TiO2 was greatly enhanced compared to pure TiO2 under visible irradiation. N dopants could retard the transformation from anatase to rutile phase. Namely, N-doping effect is attributed to the anatase phase stabilization. The results showed nitrogen atoms were incorporated into the interstitial positions of the TiO2 lattice. Ethylene was used to evaluate the photocatalytic activity of samples under visible-light illumination. The results suggested good anatase crystallization, smaller particle size, and larger surface are beneficial for photocatalytic activity of N-doped TiO2. The N-doped TiO2 catalyst prepared with ammonia to titanium isopropoxide molar ratio of 2.0 and calcinated at 400°C showed the best photocatalytic ability.

  3. Influence of Zn/Fe Molar Ratio on Optical and Magnetic Properties of ZnO and ZnFe2O4 Nanocrystal as Calcined Products of Layered Double Hydroxides

    OpenAIRE

    Abdullah Ahmed Ali Ahmed; Zainal Abidin Talib; Mohd Zobir Hussein; Moayad Husein Flaifel; Naif Mohammed Al-Hada

    2014-01-01

    The coprecipitation method has been used to synthesize layered double hydroxide (Zn-Fe-LDH) nanostructure at different Zn2+/Fe3+ molar ratios. The structural properties of samples were studied using powder X-ray diffraction (PXRD). LDH samples were calcined at 600°C to produce mixed oxides (ZnO and ZnFe2O4). The crystallite size of mixed oxide was found in the nanometer scale (18.1 nm for ZnFe2O4 and 43.3 nm for ZnO). The photocatalytic activity of the calcination products was investigated us...

  4. Volatility of ruthenium-106, technetium-99, and iodine-129, and the evolution of nitrogen oxide compounds during the calcination of high-level, radioactive nitric acid waste

    International Nuclear Information System (INIS)

    The nitrate anion is the predominant constituent in all high-level nuclear wastes. Formic acid reacts with the nitrate anion to yield noncondensable, inert gases (N2 or N2O), which can be scrubbed free of 106Ru, 129I, and 99Tc radioactivities prior to elimination from the plant by passing through HEPA filters. Treatment of a high-level authentic radioactive waste with two moles of formic acid per mole of nitrate anion leads to a low RuO4 volatility of about 0.1%, which can be reduced to an even lower level of 0.007% on adding a 15% excess of formic acid. Without pretreatment of the nitrate waste with formic acid, a high RuO4 volatility of approx. 35% is observed on calcining a 4.0 N HNO3 solution in quartz equipment at 3500C. The RuO4 volatility falls to approx. 1.0% on decreasing the initial HNO3 concentration to 1.0 N or lower. It is postulated that thermal denitration of a highly nitrated ruthenium complex leads to the formation of volatile RuO4, while decarboxylation of a ruthenium-formate complex leads to the formation of nonvolatile RuO2. Wet scrubbing with water is used to remove RuO4 from the off-gas stream. In all glass equipment, small amounts of particulate RuO2 are formed in the gas phase by decomposition of RuO4. The 99Tc volatility was found to vary from 0.2 to 1.4% on calcining HNO3 and HCOOH (formic acid) solutions over the temperature range of 250 to 6000C. These unexpectedly low volatilities of 99Tc are correlated to the high thermal stability limits of various metal pertechnetates and technetates. Iodine volatilities were high, varying from a low of 30% at 3500C to a high of 97% at 6500C. It is concluded that with a proper selection of pretreatment and operating conditions the 106Ru and 99Tc activities can be retained in the calcined solid with recycle of the wet scrubbing solution

  5. Effect of calcination temperature on the structure and visible-light photocatalytic activities of (N, S and C) co-doped TiO2 nano-materials

    International Nuclear Information System (INIS)

    Graphical abstract: (N, S and C) co-doped TiO2 samples show good photocatalytic activity for Cr(VI) reduction under visible light irradiation. - Highlights: • (N, S and C) co-doping in TiO2 can preserve the anatase form to higher temperature. • (N, S and C) co-doped TiO2 samples can absorb both UV and visible light. • The band gap energy of the sample significantly reduced after (N, S and C) co-doping. • (N, S and C) co-doped TiO2 samples effective for visible light induced reduction of Cr(VI). - Abstract: The (N, S and C) co-doped TiO2 samples (NSC-TiO2) were synthesized by the sol–gel method combining with the high energy ball milling method calcined at the different temperature (400–700 °C), employing butyl titanate as the titanium source and thiourea as the doping agent. The structures of NSC-TiO2 samples were characterized by X-ray diffraction (XRD), UV–vis diffuse reflectance spectra (DRS), X-ray photoluminescence (PL) spectroscopy, X-ray photoelectron spectroscopy (XPS), thermogravimetry and differential thermal analysis (TG–DTA), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscope (TEM), scanning electron microscopy (SEM) and nitrogen adsorption–desorption isotherms. The photocatalytic activities were checked through the photocatalytic reduction of Cr(VI) as a model compound under visible light irradiation. The results showed that the (N, S and C) co-doping and the calcination temperature played important role on the microstructure and photocatalytic activity of the samples. According to XPS spectra, sulfur was mainly attributed to the Ti−O−S bond; nitrogen was ascribed to the Ti−O−N and Ti−N bonds; carbon was assigned to the Ti−O−C bond in the NSC-TiO2 samples. (N, S and C) co-doped TiO2 samples calcinated at 500 °C exhibits higher photocatalytic activity than that of the other samples under visible light irradiation, which can be attributed to the synergic effect of its enhancing

  6. Role of crystal structure on CO2 capture by limestone derived CaO subjected to carbonation/recarbonation/calcination cycles at Ca-looping conditions

    International Nuclear Information System (INIS)

    Highlights: • CO2 capture of limestone subjected to carbonation/recarbonation/calcination cycles is affected by diffusion. • A reduction of crystallinity by ball milling favors diffusion and promotes recarbonation. • Thermal annealing enhances crystallinity and hinders recarbonation. • Milling promotes friability whereas annealing enhances the resistance of particles to fragmentation. • The solid crystal structure determines the efficiency of the novel Ca-looping concept. - Abstract: Large scale pilot plants are currently demonstrating the feasibility of the Calcium-looping (CaL) technology built on the multicyclic calcination/carbonation of natural limestone for post-combustion and pre-combustion CO2 capture. Yet, limestone derived CaO exhibits a drop of conversion when subjected to multiple carbonation/calcination cycles, which lessens the efficiency of the technology. In this paper we analyze a novel CaL concept recently proposed to mitigate this drawback based on the introduction of an intermediate stage wherein carbonation is intensified at high temperature and high CO2 partial pressure. It is shown that carbonation in this stage is mainly driven by solid-state diffusion, which is determined by the solid’s crystal structure. Accordingly, a reduction of crystallinity by ball milling, which favors diffusion, serves to promote recarbonation. Conversely, thermal annealing, which enhances crystallinity, hinders recarbonation. An initial fast phase has been identified in the recarbonation stage along which the rate of carbonation is also a function of the crystal structure indicating a relevant role of surface diffusion. This is consistent with a recently proposed mechanism for nucleation of CaCO3 on the CaO surface in islands with a critical size determined by surface diffusion. A further issue analyzed has been the effects of pretreatment and cycling on the mechanical strength of the material, whose fragility hampers the CaL process efficiency

  7. Phase evolution of vanadium oxides obtained through temperature programmed calcinations of ammonium vanadate in hydrogen atmosphere and their humidity sensing properties

    Energy Technology Data Exchange (ETDEWEB)

    Akande, A.A. [DST/CSIR National Centre for Nano-Structured Materials, P O Box 395, Pretoria, 0001 (South Africa); University of Limpopo, Department of Physics, P/Bag X1106, Sovenga, 0727 (South Africa); Linganiso, E.C.; Dhonge, B.P. [DST/CSIR National Centre for Nano-Structured Materials, P O Box 395, Pretoria, 0001 (South Africa); Rammutla, K.E. [University of Limpopo, Department of Physics, P/Bag X1106, Sovenga, 0727 (South Africa); Machatine, A.; Prinsloo, L.; Kunert, H. [School of Physics, University of Pretoria, Pretoria, 0002 (South Africa); Mwakikunga, B.W., E-mail: bmwakikunga@csir.co.za [DST/CSIR National Centre for Nano-Structured Materials, P O Box 395, Pretoria, 0001 (South Africa)

    2015-02-01

    The possibility of obtaining vanadium dioxide (VO{sub 2}) [wherein the vanadium ionic state is 4{sup +}] from a precursor of ammonium metavanadate (NH{sub 4}VO{sub 3}) bearing the ion V{sup 5+} is investigated. The reduction is carried out by calcining the NH{sub 4}VO{sub 3} powders in similar concentrations of H{sub 2} flow at varying temperatures. The resulting powders have been studied by several techniques including XRD, Raman spectroscopy, FTIR, TEM, BET and DSC. It is found that remnants of bright yellow V{sup 5+} still exist up to calcination temperatures of 100 °C after which the sky-blue VO{sub 2} dominates at calcination temperatures of 150 °C–250 °C. There is a population surge of metastable dark-blue V{sub 6}O{sub 13} (where V is in between V{sup 4+} and V{sup 5+} ionic states) between 250 °C and 300 °C. However above 350 °C the material reverts to the stable V{sup 5+} in the yellow–orange V{sub 2}O{sub 5}. XPS/EDS and VSM confirm the order of appearance to be VO{sub 2}(150 °C) → V{sub 6}O{sub 13}(200 °C) → V{sub 2}O{sub 5} (350 °C). - Highlights: • Validated the theoretical mass losses at each temperature of NH{sub 4}VO{sub 3} with TGA. • Confirmed mechanisms of formation of various stoichiometries of VO{sub x} from NH{sub 4}VO{sub 3}. • Determined the evolution of VO{sub 2}, V{sub 6}O{sub 13} and V{sub 2}O{sub 5} with temperature. • Phase diagram of VO{sub 2}, V{sub 6}O{sub 13} and V{sub 2}O{sub 5} by VSM, XPS/EDS, XRD and Raman spectra. • Comparative response of VO{sub 2}, V{sub 6}O{sub 13} and V{sub 2}O{sub 5} to humidity.

  8. Enhanced Removal of Arsenic and Antimony in the Mining Site by Calcined γ-Fe2O3/Layered Double Hydroxide Nanocomposite

    Science.gov (United States)

    Lee, Sang-Ho; Choi, Heechul; Kim, Kyoung-Woong

    2016-04-01

    Arsenic (As) and Antimony (Sb) have been recognized as harmful contaminants in aquatic environment due to its high toxicity and carcinogenicity. Especially, the contamination of arsenic in the mining areas is considered as a serious emerging environmental issue in Korea. Due to the hazardous effect of arsenic, the United States Environmental Protection Agency (US EPA) regulated maximum contamination level of arsenic to 10 μg/L in drinking water. The harmful effect on human health by excessive intake of antimony was also reported by previous studies, and severe contamination level (100 - 7,000 μg/L) of antimony reported in surface and groundwater of abandoned mining area in China and Slovakia. Therefore, US EPA regulated maximum contaminants level of antimony in drinking water to 6 μg/L. In order to remove anionic contaminants in drinking water, various type of nanomaterials have been developed. Layered double hydroxide (LDH) is the artificial anionic clay that is based on the layered structure of positively charged brucite-like layers with interlayers of anions. The LDH is one of the promising nanomaterials for the removal of anionic contaminants because it has high selectivity for arsenic, phosphate, chromium and antimony. However, the biggest problem of LDH for wastewater treatment is that the particles cannot be easily separated after the removal of contaminants. In this study, magnetic nanoparticles (γ-Fe2O3) supported LDH nanocomposite (γ-Fe2O3/LDH) was investigated to enhance magnetic particle recovery and removal efficiency for arsenic and antimony. The calcined γ-Fe2O3/LDH nanocomposites synthesized by co-precipitation method, and the crystallographic properties of maghemite (γ-Fe2O3) and layered structure of LDH were confirmed by X-ray diffraction. The nano-sized γ-Fe2O3 (30 to 50 nm) was stably attached on the surface of LDH (100 to 150 nm) and O1s spectrum by X-ray photoelectron spectroscopy (XPS) explained that there are both physical and

  9. 氯化钠增白煅烧高岭土的反应热力学%Thermodynamics of Reaction of Whitening Calcined Kaolin by Sodium Chloride

    Institute of Scientific and Technical Information of China (English)

    张锦化; 吴红丹; 雷新荣; 于吉顺; 裴大婷; 李启超

    2011-01-01

    采用氯化钠作为氯化剂氯化增白煅烧高岭土,并对相关反应进行化学热力学计算.结果表明,当氯化钠的添加量为6%,煅烧温度为900℃,煅烧时间为2h时,产品白度提高到92.3%,Fe2O3的去除率达到16.9%.其反应机理:在Al2O3参与的情况下,Fe2O3被氯化生成气态的FeCl3,900℃时,该反应的吉布斯自由能△rGθm约为-350 kJ/mol,且随着反应温度的提高,△rGθm减小,有利于反应的进行.%The calcined kaolin was whitened with sodium chloride as chloridizing agent, and thermodynamics calculations of the relative reactions were performed for the Gibbs free energy. The results showed that the whiteness of the calcined kaolin was increased to 92. 3% and the leaching rate of Fe2O3 reached 16. 9% at 900 'C for 2 h with sodium chloride added at 6 %. The reaction mechanism was that Fe2 O3 was chlorinated and formed gaseous FeCl3 with the participation of alumina. The Gibbs free energy of the reaction was about -350 kJ/mol. With increase in reaction temperature, the Gibbs free energy decreased, which was suitable to the synthesis reaction.

  10. MoO3/SiO2-ZrO2 Catalyst: Eeffect of Calcination Temperature on Physico-chemical Properties and Activities in Nitration of Toluene

    Directory of Open Access Journals (Sweden)

    Sunil Madhavrao Kemdeo

    2012-12-01

    Full Text Available 12 wt % molybdena was deposited over 1:1 silica zirconia mixed oxide support and the resultant catalyst was calcined between the 500 to 700 oC range of temperature. The samples were characterized by XRD, FT-IR, BET, SEM, NH3-TPD and pyridine adsorbed FT-IR techniques.  Nitration of toluene was studied as a model reaction over the prepared catalysts and parameters like effect of reaction temperature, effect of various solvents, catalyst reusability are studied. It was found that conversion of toluene varies with the presence of Brönsted acid sites over the catalyst surface and para-nitrotoulene selectivity is associated with pore size of the catalyst. Over the same catalysts, nitration was extended for some other aromatics. Avoid of sulfuric acid in the present process is an interesting concern in view of green chemistry. Copyright © 2012 by BCREC UNDIP. All rights reservedKeywords: MoO3/SiO2-ZrO2; SO2-ZrO2; NH3-TPD; Nitration; ortho-nitro tolueneReceived: 19th May 2012, Revised: 24th May 2012, Accepted: 26th May 2012[How to Cite: S.M. Kemdeo. (2012. MoO3/SiO2-ZrO2 Catalyst: Effect of Calcination Temperature on Physico-chemical Properties and Activities in Nitration of Toluene. Bulletin of Chemical Reaction Engineering & Catalysis, 7 (2: 92-104. doi:10.9767/bcrec.7.2.3521.92-104] [How to Link / DOI: http://dx.doi.org/10.9767/bcrec.7.2.3521.92-104 || or local: http://ejournal.undip.ac.id/index.php/bcrec/article/view/3521] | View in 

  11. 煅烧硅藻土消光助剂制备与应用研究%Synthesis and Application Research on Extinction Effect of Calcined Diatomite

    Institute of Scientific and Technical Information of China (English)

    杜玉成; 史树丽; 郭振广; 刘勇; 唐桂艳

    2009-01-01

    Calcined diatomite matting agent was firstly prepared. This matting agent applies in styrene-acrylic emulsion and acrylic emulsion. The whiteness and crystal structure are influenced by calcined temperature and additive. And the granule appearance and granularity distribution can work on extinction capability and extinction effect of high angle, respectively. Crystal product with the whiteness of 90% was synthesized by adding 4wt% NaCl and 7.5wt% amylum. The reaction temperature is 900℃ and the reaction time is 2h. When the granularity distribution mainly focuses on 8μm~25μm, theglossiness of the coating is adjacent with the angles of incidence are 60° and 85°. And the extinction efficiency can reach 51% and 65%, respectively. is%首次采用煅烧硅藻土制备出用于苯丙乳液、纯丙乳液涂料的消光助剂.煅烧温度与煅烧助剂影响产物白度和晶体结构,颗粒形貌影响产品消光性能.粒度级配影响涂层高入射角区域的消光效果.当添加4wt%NaCl、7.5wt%淀粉,900℃煅烧2h时,可获时白度为90%、晶态产物;物料粒度主要为8μm~25μm时.60°、85°的光泽度接近,消光率分别可迭51%、65%.

  12. Effect of Different Calcination Temperatures and Post Annealing on the Properties of Acetic Acid Based Sol-Gel (Na0.5K0.5)NbO3 (NKN) Thin Films

    Institute of Scientific and Technical Information of China (English)

    Sebastian Wiegand; Stefan Flege; Olaf Baake; Wolfgang Ensinger

    2013-01-01

    (Na0.5K0.5)NbO3 (NKN) lead free thin films were synthesized by means of an acetic acid based sol-gel process on Pt/Ti/SiO2/Si substrates.Na-acetate,K-acetate and Nb-pentaethoxide were used as metal precursors and acetic acid as the solvent.The effect of different calcination temperatures on the properties of the NKN films was investigated by X-ray diffraction,scanning electron microscopy,leakage current and hysteresis measurements.Low calcination temperatures led to low currents at high electric fields whereas high calcination temperatures led to low currents at low electric fields.Based on these findings calcination at low temperature was combined with a post annealing treatment.Low leakage currents of 4 × 10-4 A/cm2 at 150 kV/cm and 2Pr and 2Ec values of 28 μC/cm2 and 150 kV/cm,respectively,could be obtained.All films were single phase NKN with random crystal orientations and no crack or pore formation was visible on the surface.

  13. Influence of calcination parameters on the synthesis of N-doped TiO{sub 2} by the polymeric precursors method

    Energy Technology Data Exchange (ETDEWEB)

    Dawson, Margaret, E-mail: missmargaretdawson@gmail.com [Department of Materials Engineering, Universidade Federal de São Carlos, Rodovia Washington Luis KM 235 SP-310, São Carlos CEP 13565-905, São Paulo (Brazil); Soares, Gabriela Byzynski, E-mail: gabi.byzynski@gmail.com [Department of Chemistry, Universidade Federal de São Carlos, Rodovia Washington Luis KM 235 SP-310, São Carlos CEP 13565-905, São Paulo (Brazil); Embrapa Instrumentação, Rua XV de Novembro 1452, São Carlos CEP 13560-970, São Paulo (Brazil); Ribeiro, Caue, E-mail: caue.ribeiro@embrapa.br [Embrapa Instrumentação, Rua XV de Novembro 1452, São Carlos CEP 13560-970, São Paulo (Brazil)

    2014-07-01

    In this paper, the influence of calcination parameters on the synthesis of N:TiO{sub 2} catalysts obtained through the polymeric precursors method was evaluated. The powders were prepared by annealing Ti{sup 4+} precursor resins at different temperature-time conditions in air, resulting in powders with different degrees of crystallinity for N doping, which was done by adding urea to the as-prepared powders and calcining in N{sub 2} atmosphere. The N doping process resulted in band gap narrowing of TiO{sub 2} and, varying annealing temperature and time, can be an alternative method for preferential formation of substitutional N or interstitial N. It was found that the percentage of interstitial N increased with an increase in annealing temperature, resulting in the complete absence of substitutional N at 400 °C. The photocatalytic performance of the powders was evaluated using Rhodamine-B and Atrazine solutions under ultraviolet and visible irradiations. The coefficients revealed that interstitial N had a positive correlation to both ultraviolet and visible photoactivity. In contrast, substitutional N showed a negative correlation. Further, the ratio of substitutional N to interstitial N indicated a strong negative correlation to ultraviolet light photoactivity and no correlation to visible light photoactivity. However, substitutional N should be controlled for better photocatalytic properties. - Graphical abstract: The temperature influences to promote higher quantities of Interstitial N doped TiO{sub 2} than Substitutional and due to difference between energies levels for substitutional N doped TiO{sub 2} and Interstitial N doped TiO{sub 2}, it is presented difference on photocatalytic activity. - Highlights: • Temperature and time of synthesis of N doping TiO{sub 2} could affect the type of N (interstitial and substitutional N). • The percentage of interstitial N increased with an increase in annealing temperature. • Interstitial N improves ultraviolet and

  14. On Sulfuric Acid Leaching in Magnetized Reduction of Zinc from Calcines%磁化还原焙砂硫酸浸出探索

    Institute of Scientific and Technical Information of China (English)

    曹子宇; 陈永明

    2015-01-01

    In order to address the problem of iron flowing into solution in profusion in the process of zinc reduction which causes environmental pollution,this paper conducts a systematic research into the process of sulfuric acid leaching in reducing zinc from calcines. By adopting single-factor conditional testing,this paper thoroughly investigates various factors that affect the sulfuric acid leaching including the initial acidity,liquid-solid ratio,temperature and duration. The optimized testing shows that under the optimized condition with the initial acidity of 120 g/L,at liquid-solid ratio of 7∶1,at a temperature of 60℃and in 2 hours the zinc leaching rate reaches 88.5%,the iron leaching rate 10.6% and the leached iron is almost totally ferrous iron. The result explains one step up to zinc calcine magnetized reduction of a reduction.%针对锌浸出过程中铁大量进入溶液,由此带来的环境污染问题,本研究对锌还原焙砂的硫酸浸出过程进行系统研究.采用单因素条件试验法,详细考察硫酸初始酸度、液固比、温度和时间对还原焙砂浸出过程的影响,并在最佳工艺条件下进行综合扩大试验.结果表明,在硫酸初始酸度120 g/L、液固比7∶1、温度60℃、时间2 h的优化条件下,锌的浸出率达到了88.5%,铁的浸出率为10.6%.浸出液中铁几乎全部为二价铁离子,表明对锌焙砂的磁化还原过还原了.

  15. Calcinated gold nanoparticle arrays for on-chip, multiplexed and matrix-free mass spectrometric analysis of peptides and small molecules

    Science.gov (United States)

    Hinman, Samuel S.; Chen, Chih-Yuan; Duan, Jicheng; Cheng, Quan

    2016-01-01

    A patterned gold nanoparticle microarray, functionalized with a nanoscale silicate coating, has been developed for on-chip, high-throughput mass spectrometric analyses of biomolecules with minimal sample preparation and reagent costs. Fabrication was realized by the combination of layer-by-layer functionalization of the nanoparticles with suitable polyelectrolytes, followed by fluidic patterning of the glass microarray support and calcination for permanent fixation of the nano-coating. Performance of the microarray was evaluated for surface-assisted laser-desorption/ionization mass spectrometry (SALDI-MS), where the nano-silicate coating was found to enhance SALDI efficiency, resulting in comparable performance to some common organic matrices for small and medium sized molecules. Performance contributing factors of this material have been discussed; heat confinement and interband transition/plasmonic resonance may play important roles. Taking the accessibility of fabrication, performance, and reusability of this substrate together, the material developed here provides a new tool for multiplexed and chip-based mass spectrometric analysis.A patterned gold nanoparticle microarray, functionalized with a nanoscale silicate coating, has been developed for on-chip, high-throughput mass spectrometric analyses of biomolecules with minimal sample preparation and reagent costs. Fabrication was realized by the combination of layer-by-layer functionalization of the nanoparticles with suitable polyelectrolytes, followed by fluidic patterning of the glass microarray support and calcination for permanent fixation of the nano-coating. Performance of the microarray was evaluated for surface-assisted laser-desorption/ionization mass spectrometry (SALDI-MS), where the nano-silicate coating was found to enhance SALDI efficiency, resulting in comparable performance to some common organic matrices for small and medium sized molecules. Performance contributing factors of this material

  16. 强化悬浮式RSP型分解炉石油焦燃烧特性实验及数值模拟研究%Experimental and numerical research on petroleum coke combustion characteristics in reinforced suspension calciner

    Institute of Scientific and Technical Information of China (English)

    毛娅; 陈作炳; 陈定方; 卢海波

    2008-01-01

    The main physico-chemical processes taking place in the calciner are coal combustion. Petroleum coke,as an economical alternative fuel for the pulverized coal,is widely used in the calciner. The present article is devoted to introduce the research works on make use of petroleum coke as a substitutional fuel of calciner,which consists of two major parts. In the first part,the basic properties of the petrolenm coke and its characteristics of grindability,devolatilization,ignition and combustion were investigated by serials of experiment. And in the second part,a numerical model was also presented to simulate the combustion processes taking place in an industrial reinforced suspension calciner. The numerical model was based on two-phase theory and fast reaction PDF model. The results of study show that petroleum coke is a suitable fuel for RSP calciner and the conclusions to be drawn will help in the optimization of a given calciner.%水泥生产中分解炉内主要化学物理过程是煤粉的燃烧.与煤粉相比,石油焦是一种经济的替代燃料.本文首先通过实验测试出石油焦燃烧的物理化学特性,根据这些特性建立了石油焦在强化悬浮式RSP型分解炉中燃烧的数值模拟模型.该模型结合气固二相流理论,采用快速反应的PDF模型,对分解炉内石油焦的燃烧过程进行了数值模拟,揭示了分解炉内石油焦的燃烧机理.研究结果表明RSP型分解炉的炉型适宜于石油焦的燃烧,并且数值模拟的结果能为石油焦在分解炉内优化燃烧提供了理论依据和有利的信息.

  17. Effects of Zr/Ti molar ratio in SO42-/ZrO2-TiO2 calcined at different temperatures on its surface properties and glucose reactivity in near-critical methanol

    Institute of Scientific and Technical Information of China (English)

    Lincai Peng; Junping Zhuang; Lu Lin

    2012-01-01

    Effects of Zr/Ti molar ratio in SO42-/ZrO2-TiO2 solid acid catalyst calcined at different temperatures on its surface properties and catalytic activity were thoroughly investigated in this paper.The physicochemical characteristics of prepared samples were determined by N2 adsorptiondesorption,XRD,NH3-TPD and XPS techniques,respectively.It was found that the crystallization temperature of the samples increased after the combination of ZrO2 and TiO2; and phase transformations from the anatase to the rutile of TiO2 species and the tetragonal to the monoclinic of ZrO2 species were effectively suppressed at higher temperature.The sample with a Zr/Ti molar ratio of 3/1 calcined at 450 ℃ showed the highest surface area and the most acid sites among all the tested samples.The acid site densities of samples were relatively closed to each other if they were calcined at the same temperature,however,decreased with the calcination temperature.The result indicates that the sulfur content in samples is a crucial factor to control the acid site density.Calcining the sample at 650 ℃ and higher temperatures resulted in a significant desorption of sulfate ion on the samples.The synthesized samples were evaluated as a potential catalyst for glucose conversion under the nearcritical methanol conditions (200 ℃/4 MPa).The results suggested that the relatively weaker acid sites of the catalyst were more favorable for the accumulation of methyl glucosides,while the moderate acid sites were responsible for the formation of methyl levulinate.The catalytic activity for methyl levulinate production almost increases linearly with the catalyst acid site density.The catalyst deactivation is due to the loss of sulfate ion and the two catalysts with Zr/Ti molar ratios of 3/1 and 1/3 could effectively alleviate the deactivation caused by sulfate solution in the reaction medium and can be reused after calcination with the reuse rate of over 90% in terms of the methyl levulinate selectivity.

  18. Influence of calcinable cylinders cast in cobalt-chromium alloy on the passivity of implant-supported frameworks = Influência de cilindros calcináveis fundidos em cobalto-cromo na passividade de próteses implanto-suportadas

    Directory of Open Access Journals (Sweden)

    Triches, Diego Fernandes

    2009-01-01

    Full Text Available Objetivo: Este trabalho avaliou a influência da utilização de cilindros calcináveis no grau de passividade de infra-estruturas que simulam uma prótese parcial fixa de três elementos sobre dois implantes. Metodologia: Foram utilizados dois implantes de hexágono externo de 3,75 mm×10 mm, com seus respectivos pilares intermediários, fixados numa base de aço, formando o modelomestre. A partir disto, foram fabricadas dez infra-estruturas em liga de cobalto-cromo através da técnica de fundição por indução. Foram criados dois grupos: Grupo 1 utilizando cilindros pré-usinados para a fabricação de cinco infra-estruturas; Grupo 2 cinco infra-estruturas fundidas com cilindros de plástico calcináveis. Para avaliação da passividade foram utilizados extensômetros colados na região oclusal e cervical do pôntico das infra-estruturas. A medição foi realizada no momento do aperto do segundo parafuso protético com torque de 10Ncm. Os dados foram analisados pelo teste t de Student (α=0,05. Resultados: As médias (desvio-padrão dos grupos foram de 39,16 (24,74 mV/V no Grupo 1 e 43,76 (21,13 mV/V no Grupo 2. Não houve diferença estatisticamente significante entre os grupos (P=0,815. Conclusão: Considerando-se as limitações deste trabalho, sugere-se que o uso de cilindros calcináveis obtém o mesmo grau de passividade que o uso de cilindros pré-usinados

  19. Hydrogen-Rich Gas Production by Sorption Enhanced Steam Reforming of Woodgas Containing TAR over a Commercial Ni Catalyst and Calcined Dolomite as CO2 Sorbent

    Directory of Open Access Journals (Sweden)

    Vincenzo Naso

    2013-07-01

    Full Text Available The aim of this work was the evaluation of the catalytic steam reforming of a gaseous fuel obtained by steam biomass gasification to convert topping atmosphere residue (TAR and CH4 and to produce pure H2 by means of a CO2 sorbent. This experimental work deals with the demonstration of the practical feasibility of such concepts, using a real woodgas obtained from fluidized bed steam gasification of hazelnut shells. This study evaluates the use of a commercial Ni catalyst and calcined dolomite (CaO/MgO. The bed material simultaneously acts as reforming catalyst and CO2 sorbent. The experimental investigations have been carried out in a fixed bed micro-reactor rig using a slipstream from the gasifier to evaluate gas cleaning and upgrading options. The reforming/sorption tests were carried out at 650 °C while regeneration of the sorbent was carried out at 850 °C in a nitrogen environment. Both combinations of catalyst and sorbent are very effective in TAR and CH4 removal, with conversions near 100%, while the simultaneous CO2 sorption effectively enhances the water gas shift reaction producing a gas with a hydrogen volume fraction of over 90%. Multicycle tests of reforming/CO2 capture and regeneration were performed to verify the stability of the catalysts and sorbents to remove TAR and capture CO2 during the duty cycle.

  20. Ethyl thiosemicarbazide intercalated organophilic calcined hydrotalcite as a potential sorbent for the removal of uranium(Ⅵ)and thorium(Ⅳ) ions from aqueous solutions

    Institute of Scientific and Technical Information of China (English)

    T.S.Anirudhan; S.Jalajamony

    2013-01-01

    This work was conducted to determine the practicability of using a new adsorbent 4-ethyl thiosemicarbazide intercalated,organophilic calcined hydrotalcite (ETSC-OHTC) for the removal of uranium (U(Ⅵ)),and thorium (Th(Ⅳ)) from water and wastewater.The FTIR analysis helped in realizing the involvement of nitrogen and sulphur atoms of ETSC in binding the metal ions through complex formation.Parameters like adsorbent dosage,solution pH,initial metal ions concentration,contact time and ionic strength,that influence adsorption phenomenon,were studied.The optimum pH for maximum adsorption of U(Ⅳ) and Th(Ⅳ) was found to be in the range 4.0-6.0.The contact time required for reaching equilibrium was 4 hr.The pseudo second-order kinetic model was the best fit to represent the kinetic data.Analysis of the equilibrium adsorption data using Langmuir,Freundlich and Sips models showed that the Freundlich model was well suited to describe the metal ions adsorption.The KF values were 25.43 and 29.11 mg/g for U(Ⅵ) and Th(Ⅳ),respectively,at 30℃.The adsorbent can be regenerated effectively from U(Ⅵ) and Th(Ⅳ) loaded ones using 0.01 mol/L HCl.The new adsorbent was quite stable for many cycles,without much reduction in its adsorption capacity towards the metals.

  1. Processing and properties of superconducting La[sub 1. 85]Sr[sub 0. 15]CuO[sub 4] powder by double-step calcining

    Energy Technology Data Exchange (ETDEWEB)

    Alconchel, Silvia A. (Instituto de Investigaciones en Catalisis y Petroquimica, INCAPE (FIQ,UNL-CONICET), Santiago del Estero 2829, 3000 Santa Fe (Argentina)); Ulla, Maria A. (Instituto de Investigaciones en Catalisis y Petroquimica, INCAPE (FIQ,UNL-CONICET), Santiago del Estero 2829, 3000 Santa Fe (Argentina)); Lombardo, Eduardo A. (Instituto de Investigaciones en Catalisis y Petroquimica, INCAPE (FIQ,UNL-CONICET), Santiago del Estero 2829, 3000 Santa Fe (Argentina))

    1994-11-01

    The preparation of single-phase tetragonal La[sub 1.85]Sr[sub 0.15]CuO[sub 4] powder using two consecutive thermal cycles is described. Freeze-dried or evaporated lanthanum, strontium and copper acetates were used as precursor materials. The effect of the reaction temperature (in the second cycle) on the characteristics of high-T[sub c] superconductor was studied by X-ray diffraction, idometric titration, temperature-programmed reduction, scanning electron microscopy and electrical resistivity measurements.Monophasic powder was obtained by reacting freeze-dried precursors at a final temperature of 1253 K for 8 h. The reduction of La[sub 1.85]Sr[sub 0.15]CuO[sub 4] occurred in one step at 744 K. Thermal treatments in either N[sub 2] or O[sub 2] strongly affect the hydrogen consumption profile.Monophasic sintered pellets were obtained from freeze-dried precursors calcined at final temperatures between 973 and 1253 K. The microstructure of sintered bodies was characterized by equiaxed grains of about 0.5 [mu]m. Evaporated precursors did not yield powder or single phase sintered material, and gave a grain size of about 1 [mu]m. The critical temperature ranged between 36.7 and 37.3 K and [Delta]T[sub c] between 2.8 and 4.8 K. ((orig.))

  2. Fibrous TiO2 prepared by chemical vapor deposition using activated carbon fibers as template via adsorption, hydrolysis and calcinations

    Institute of Scientific and Technical Information of China (English)

    Hui-na YANG; Li-fen LIU; Feng-lin YANG; Jimmy C. YU

    2008-01-01

    TiO2 fibers were prepared via alternatively introducing water vapor and Ti precursor carried by Ne to an APCVD (chemical vapor deposition under atmospheric pressure) reactor at <200 ℃. Activated carbon fibers (ACFs) were used as templates for deposition and later removed by calcinations. The obtained catalysts were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brtmauer, Emmett and Teller (BET) and X-ray diffraction (XRD) analysisThe pores within TiO2 fibers included micro-range and meso-range, e.g., 7 nm, and the specific surface areas for TiO2 fibers were 141 m2/g and 148 m2/g for samples deposited at 100 ℃ and 200 ℃ (using ACF1700 as template), respectively. The deposition temperature significantly influenced TiO2 morphology. The special advantages of this technique for preparing porous nano-material include no consumption of organic solvent in the process and easy control of deposition conditions and speeds.

  3. Ethyl thiosemicarbazide intercalated organophilic calcined hydrotalcite as a potential sorbent for the removal of uranium(VI) and thorium(IV) ions from aqueous solutions.

    Science.gov (United States)

    Anirudhan, T S; Jalajamony, S

    2013-04-01

    This work was conducted to determine the practicability of using a new adsorbent 4-ethyl thiosemicarbazide intercalated, organophilic calcined hydrotalcite (ETSC-OHTC) for the removal of uranium (U(VI)), and thorium (Th(IV)) from water and wastewater. The FTIR analysis helped in realizing the involvement of nitrogen and sulphur atoms of ETSC in binding the metal ions through complex formation. Parameters like adsorbent dosage, solution pH, initial metal ions concentration, contact time and ionic strength, that influence adsorption phenomenon, were studied. The optimum pH for maximum adsorption of U(VI) and Th(IV) was found to be in the range 4.0-6.0. The contact time required for reaching equilibrium was 4 hr. The pseudo second-order kinetic model was the best fit to represent the kinetic data. Analysis of the equilibrium adsorption data using Langmuir, Freundlich and Sips models showed that the Freundlich model was well suited to describe the metal ions adsorption. The K(F) values were 25.43 and 29.11 mg/g for U(VI) and Th(IV), respectively, at 30 degrees C. The adsorbent can be regenerated effectively from U(VI) and Th(IV) loaded ones using 0.01 mol/L HCl. The new adsorbent was quite stable for many cycles, without much reduction in its adsorption capacity towards the metals.

  4. Self-reactivated mesostructured Ca-Al-O composite for enhanced high-temperature CO2 capture and carbonation/calcination cycles performance.

    Science.gov (United States)

    Chang, Po-Hsueh; Huang, Wei-Chen; Lee, Tai-Jung; Chang, Yen-Po; Chen, San-Yuan

    2015-03-25

    In this study, highly efficient high-temperature CO2 sorbents of calcium aluminate (Ca-Al-O) mesostructured composite were synthesized using presynthesized mesoporous alumina (MA) as a porous matrix to react with calcium nitrate through a microwave-assisted process. Upon annealing at 600 °C, a highly stable mesoporous structure composed of poorly crystalline Ca12Al14O33 phase and the CaO matrix was obtained. The Ca-Al-O mesostructured sorbents with a Ca(2+)/Al(3+) ratio of 5:1 exhibit an enhanced increasing CO2 absorption kinetics in the CO2 capture capacity from 37.2 wt % to 48.3 wt % without apparent degradation with increasing carbonation/calcination cycling up to 50 at 700 °C due to the strong self-reactivation effect of the mesoporous Ca-Al-O microstructure. Remarkable improvements in the CaO-CaCO3 conversion attained from the mesostructured Ca-Al-O composite can be explained using the concept combined with available mesoporous structure and Ca12Al14O33 phase content. However, a high Ca(2+)/Al(3+) =8:1 Ca-Al-O composite causes degradation because the pores become blocked and partial sintering induces CaO agglomeration. PMID:25730384

  5. Synthesis and characterization of ZSM-5 and calcined kaolin evaluation using the content of structure-directing; Sintese e caracterizacao da zeolita ZSM-5 utilizando caulim calcinado e avaliacao do teor de direcionador de estrutura

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, J.J.; Silva, V.J. da; Rodrigues, M.G.F., E-mail: jocielys@yahoo.com.br [Universidade Federal de Campina Grande (LABNOV/UAEQ/UFCG), PB (Brazil). Unidade Academica de Engenharia Quimica. Lab. de Desenvolvimento de Novos Materiais

    2012-07-01

    This study aims to evaluate the effect of the structure-directing content, tetrapropylammonium bromide, on the structural and morphological characteristics of ZSM-5 zeolite obtained using calcined kaolin as silicon and aluminum. The samples were characterized by XRD, EDX, SEM and Physics Adsorption N{sub 2}. Trough X ray diffraction patterns was possible to observed the formation of the structure of ZSM-5 with intense peaks and well-defined characteristic of crystalline. The micrographs showed that the samples consist of agglomerates and/or aggregates of particles characteristic of the MFI structure typical of ZSM-5 zeolite. And through the adsorption-desorption isotherms physical N2 was possible to observe that the samples show hysteresis type I typical of microporous materials with specific surface areas of 218 and 222 m{sup 2}/g. Therefore, the use of calcined kaolin to obtain ZSM-5 zeolite was effective. (author)

  6. Application of the Rietveld method in powders of strontium-doped lanthanum manganite calcined in different temperatures; Aplicacao do metodo de Rietveld em pos de manganito de lantanio dopado com estroncio calcinados em diferentes temperaturas

    Energy Technology Data Exchange (ETDEWEB)

    Chiba, R.; Vargas, R.A.; Martinez, L.G.; Andreoli, M.; Seo, E.S.M. [Instituto de Pesquisas Energeticas e Nucleares (CCTM/IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Ciencia e Tecnologia de Materiais. Lab. de SOFC: Insumos e Componentes

    2010-07-01

    The strontium-doped lanthanum manganite (LSM) is a ceramic material used as cathode in device called High Temperature Solid Oxide Fuel Cell. In this work, the LSM was synthesized by the citrate technique with the objective to get powders without the formation of secondary phases, such as lanthanum oxide and the lanthanum hydroxide, harmful for the functional performance of the device. The definitive calcination temperatures had been 700, 900 and 1100 deg C, due the decomposition of the polymeric precursors to present stabilization from 480 deg C. The analysis by X-ray diffraction of the calcined powders in different temperatures shows the formation only of phase LSM of hexagonal crystalline structure, type pseudo-perovskite. Using the refinement of Rietveld was determined the parameters and volumes of unity cells, atomic positions and occupations. These results confirm that the chemical compositions obtained are similar to the nominal. (author)

  7. Effects of calcination treatment on the morphology, crystallinity, and photoelectric properties of all-solid-state dye-sensitized solar cells assembled by TiO2 nanorod arrays.

    Science.gov (United States)

    Sun, Xianmiao; Sun, Qiong; Li, Yang; Sui, Lina; Dong, Lifeng

    2013-11-14

    TiO2 has been extensively investigated due to its unique photoelectric properties. In this study, oriented single-crystal rutile TiO2 nanorod arrays were synthesized and then calcined at different temperatures in the atmosphere. The morphology and crystalline characterization indicated that the length of TiO2 nanorods increased rapidly and the nanorods became aggregated and fragile after calcination, yet the sintering treatment seemed to have almost no effect on the crystallinity. To obtain the all-solid-state, dye-sensitized solar cells (DSSCs), a newly reported solid inorganic semiconductor, CsSnI2.95F0.05, was employed as the electrolyte, and the Pt deposited on the conductive side of the fluorine-doped tin oxide (FTO) glass substrate was used as the counter-electrode. The effects of the calcination treatment on the photoelectric properties of the solar cells, including external quantum efficiency (EQE), open circuit voltage (V(OC)), short-circuit current (J(SC)), and photoelectric conversion efficiency (η), were investigated under the illumination of a solar simulator. As a result, all of the EQE, V(OC), J(SC), and η values of the cells first increased and then declined with the increase of calcination temperatures, and the highest η of 2.81% was obtained by the cell assembled with its TiO2 electrode sintered at 450 °C for 3 h, a value almost 2.5 times that of the non-sintered sample (1.1%).

  8. Effect of calcination temperature on the H{sub 2}O{sub 2} decomposition activity of nano-crystalline Co{sub 3}O{sub 4} prepared by combustion method

    Energy Technology Data Exchange (ETDEWEB)

    Makhlouf, M.Th. [Chemistry Department, Faculty of Science, Assiut University, 71516 Assiut (Egypt); Abu-Zied, B.M., E-mail: babuzied@aun.edu.eg [Chemistry Department, Faculty of Science, Assiut University, 71516 Assiut (Egypt); Mansoure, T.H. [Chemistry Department, Faculty of Science, Assiut University, 71516 Assiut (Egypt)

    2013-06-01

    Cobalt oxide nano-particles were prepared by combustion method using urea as a combustion fuel. The effects of calcination temperature, 350–1000 °C, on the physicochemical, surface and catalytic properties of the prepared Co{sub 3}O{sub 4} nano-particles were studied. The products were characterized by thermal analyses (TGA and DTA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques. Textural features of the obtained catalysts were investigated using nitrogen adsorption at −196 °C. X-ray diffraction confirmed that the resulting oxide was pure single-crystalline Co{sub 3}O{sub 4} nano-particles. Transmission electron microscopy indicating that, the crystallite size of Co{sub 3}O{sub 4} nano-crystals was in the range of 8–34 nm. The catalytic activities of prepared nano-crystalline Co{sub 3}O{sub 4} catalysts were tested for H{sub 2}O{sub 2} decomposition at 35–50 °C temperature range. Experimental results revealed that, the catalytic decomposition of H{sub 2}O{sub 2} decreases with increasing the calcination temperature. This was correlated with the observed particle size increase accompanying the calcination temperature rise.

  9. Preparation and properties of Li{sub 1.3}Al{sub 0.3}Ti{sub 1.7}(PO{sub 4}){sub 3} by spray-drying and post-calcining method

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Bo; Li, Xinhai, E-mail: yangbo@csu.edu.cn; Guo, Huajun; Wang, Zhixing; Xiao, Wei

    2015-09-15

    Highlights: • The spray-drying method is a simple and energy-saving method to prepare LATP. • The compounds with single phase structure of LATP were synthesized at 700–900 °C. • The ionic conductivity of the prepared LATP was maximized at 0.622 mS cm{sup −1} at 800 °C. - Abstract: Solid state electrolyte Li{sub 1.3}Al{sub 0.3}Ti{sub 1.7}(PO{sub 4}){sub 3} is synthesized by spray-drying and post-calcining method. X-ray diffraction is employed to characterize the powders calcined in the range of 700–900 °C for 2 h, which indicates powders are well crystallized. FTIR shows trivalent cation Al{sup 3+} is substituted by Ti{sup 4+}. The composite material appears as 2–5 μm spherical particle. TG–DTA results confirm that the thermal decomposition of precursors obtained by spray-drying method occurred at lower temperature compares with solid phase synthesis method and sol–gel method. The ionic conductivity of the pellets reaches a maximum of 0.622 mS cm{sup −1} at calcining temperature of 800 °C.

  10. Effects of calcination temperature and solution pH value on the structural and magnetic properties of Ba2Co2Fe12O22 ferrite via EDTA-complexing process

    International Nuclear Information System (INIS)

    Y-type hexagonal Ba2Co2Fe12O22 was prepared via a simple EDTA-complexing process using corresponding metal nitrates as raw materials and ethylene diamine tetraacetic acid (EDTA) as complexing agent. The decomposition process of the precursor, formation process of Ba2Co2Fe12O22, structure, morphology and magnetic properties of the particles were investigated by thermogravimetric analysis and differential thermal analysis (TGA-DTA), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). The effects of calcination temperature and solution pH value on the structure and magnetic properties of the particles were studied. The results showed that the formation of single phase Ba2Co2Fe12O22 was achieved by controlling the calcination temperature ≥1000 deg. C. Meanwhile, the pH value ≥8 of initial solution was necessary to form stable metal-EDTA complexes and to produce high quality Ba2Co2Fe12O22. The magnetic properties showed dependence on the preparation conditions and microstructures. Saturation magnetization (Ms) and coercivity (Hc) were obtained in the range of 30.2-44.8 emu g-1 and 91.7-1953.7 Oe for samples calcined from 700 to 1200 deg. C, and 28.8-33.4 emu g-1 and 190.1-84.0 Oe for samples from initial solution of pH 3.8-10.1.

  11. 焙烧硼钠钙石在高固液化比氯化铵溶液中的熔解动力学%Dissolution Kinetics of Calcined Ulexite in Ammonium Chloride Solutions at High Solid-to-Liquid Ratios

    Institute of Scientific and Technical Information of China (English)

    G(U)R; Aycan

    2006-01-01

    The dissolution kinetics of calcined ulexite in ammonium chloride solutions at high solid-to-liquid ratios were investigated. In the experiments, calcination temperature, solution concentration, reaction temperature, and prehydration were chosen as parameters. It was observed that the dissolution rate increased with increasing calcination temperature, solution concentration, and reaction temperature, whereas it was not affected by pre-hydration. Employing graphical and statistic methods, the dissolution rate, based on homogeneous reaction model,can be given as: (1-X(B2O3))-1-1=k(c(NH4Cl))1.982t. The activation energy for the dissolution of the ulexite sample calcined at 160 ℃ was found to be

  12. Micro-structural characterization of the hydration products of bauxite-calcination-method red mud-coal gangue based cementitious materials

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiaoming [State Key Laboratory of Advanced Metallurgy, School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Zhang, Na [Green Construction Materials and Circulation Economy Center, Architectural Design and Research Institute of Tsinghua University Co., Ltd., Beijing 100084 (China); Yao, Yuan, E-mail: yuanyaocas@163.com [School of Engineering and Computer Science, University of the Pacific, Stockton, CA 95211 (United States); Sun, Henghu; Feng, Huan [School of Engineering and Computer Science, University of the Pacific, Stockton, CA 95211 (United States)

    2013-11-15

    Highlights: • Al{sup IV} and Al{sup VI} both exist in the hydration products. • Increase of Ca/Si ratio promotes the conversion from [AlO{sub 4}] to [AlO{sub 6}]. • Polymerization degree of [SiO{sub 4}] in the hydration products declines. -- Abstract: In this research, the micro-structural characterization of the hydration products of red mud-coal gangue based cementitious materials has been investigated through SEM-EDS, {sup 27}Al MAS NMR and {sup 29}Si MAS NMR techniques, in which the used red mud was derived from the bauxite calcination method. The results show that the red mud-coal gangue based cementitious materials mainly form fibrous C-A-S-H gel, needle-shaped/rod-like AFt in the early hydration period. With increasing of the hydration period, densification of the pastes were promoted resulting in the development of strength. EDS analysis shows that with the Ca/Si of red mud-coal gangue based cementitious materials increases, the average Ca/Si and Ca/(Si + Al) atomic ratio of C-A-S-H gel increases, while the average Al/Si atomic ratio of C-A-S-H gel decreases. MAS NMR analysis reveals that Al in the hydration products of red mud-coal gangue based cementitious materials exists in the forms of Al{sup IV} and Al{sup VI}, but mainly in the form of Al{sup VI}. Increasing the Ca/Si ratio of raw material promotes the conversion of [AlO{sub 4}] to [AlO{sub 6}] and inhibits the combination between [AlO{sub 4}] and [SiO{sub 4}] to form C-A-S-H gel. Meanwhile, the polymerization degree of [SiO{sub 4}] in the hydration products declines.

  13. 锌焙砂一段酸性浸出试验研究%Study on Single -stage Acid Leaching of Zinc Calcine

    Institute of Scientific and Technical Information of China (English)

    阙绍娟; 陈燕清; 马少健; 何春林

    2011-01-01

    The test on single - stage acid leaching of zinc calcine had been proceed. The effects of stirring speed, particle size, leaching temperature, initial acidity of sulfuric acid and ratio of liquid to solid were studied on the leaching rates of zinc and iron. The results showed that initial acidity of sulfuric acid and liquid -solid ratio were the most important factors on leaching. Under the condition of leaching temperature 55℃, initial acidity of sulfuric acid 120 g/L, leaching time 0.5 h,liquid- solid ratio 6: 1 and stirring rate 500 r/min, the leaching rate of zinc and iron was 81.33% and 3.45% respectively, which basically achieved selective leaching of zinc and iron.%对锌焙砂进行了一段酸性浸出试验研究,考察了搅拌速度、矿样粒度、浸出温度、初始酸度、液固比等因素对Zn和Fe浸出率的影响规律.试验结果表明:初始酸度和液固比是影响浸出的最重要因素,锌焙砂在55℃、初始酸度120 g/L、液同比6:1和搅拌速度为500 r/min的条件下浸出0.5 h,Zn的浸出率为81.33%、Fe的浸出率为3.45%,基本能够实现Zn、Fe的选择性浸出.

  14. Study on the influence of CaO on NH{sub 3}+NO+O{sub 2} reaction system in pre-calciner

    Energy Technology Data Exchange (ETDEWEB)

    Tang, J.S.; Song, Q.; Fu, S.L.; Wu, X.Y.; Yao, Q. [Tsinghua Univ., Beijing (China). Inst. of Thermal Engineering

    2013-07-01

    This paper studied the influence of CaO on NH{sub 3}+NO+O{sub 2} reaction system in pre-calciner. Experiments were carried out in a fixed bed reactor. Influence of CaO on NH{sub 3}+NO+O{sub 2} reaction, NH{sub 3} oxidation, NH{sub 3} decomposition and NO reduction by NH{sub 3} at O{sub 2} free condition were studied. NH{sub 3} conversion rates and product selectivities were obtained for each reaction condition. It was proved that the influence of CaO on SNCR performance changed with temperature. CaO promoted SNCR performance at 650 C and changed to inhibit SNCR performance when temperature increased above 700 C. CaO influenced the reaction of NH{sub 3}+NO+O{sub 2} mainly by catalyzing NH{sub 3} oxidation. NH{sub 3} conversion rate and NO selectivity decreased when NH{sub 3} concentration increased. Addition of NO into NH{sub 3} heterogeneous oxidation had little effect on NH{sub 3} conversion rate but decreased NO selectivity. A reaction mechanism for NH{sub 3}NO+O{sub 2} reaction on CaO surface was proposed. Heterogeneous reaction model of NH{sub 3}+NO+O{sub 2} on CaO surface was established based on the proposed reaction mechanism. Numerical results showed that the reaction model in this paper could predict NH3 oxidation and NH{sub 3}+NO+O{sub 2} reaction on CaO surface very well.

  15. Integration of a calcined bovine bone and BMSC-sheet 3D scaffold and the promotion of bone regeneration in large defects.

    Science.gov (United States)

    Liu, Yihan; Ming, Leiguo; Luo, Hailang; Liu, Wenjia; Zhang, Yongjie; Liu, Hongchen; Jin, Yan

    2013-12-01

    Reconstruction of large area bone defect with mechanical integrity to the skeleton is important for patient's rehabilitation. However with the limitation of scaffold material and suitable seed cell sources, the best treating strategy remains to be identified though various tissue engineering methods were reported. In this study, we investigated the feasibility of applying calcined bovine bone (CBB) which was coated by allograft bone marrow mesenchymal stem cells (BMSC)-sheet as a 3D scaffold material in bone repairing tissue engineering. The new scaffold material was implanted into osteoporosis rat cranial bone defects and repairing critical size bone defects (8 mm diameter). Data showed that CBB-BMSC-sheet combination had a stronger potential in osteogenic differentiation and mineralized formation both in vitro and in vivo than CBB-BMSC combination. In in vitro study BMSC-sheet had a more feasible characteristic upon bone repairing including richer ECM, larger mineralized area and stronger ALP activity in addition with a significant higher mRNA expression of osteogenic maker such as BMP-2, b-FGF, Col 1a1, OSX and Runx-2 than the control group. In in vivo study 3D reconstruction of micro CT, HE staining and bone strength results showed that newly formed bone in CBB-BMSC-sheet group was significant higher than that in CBB-BMSC group at 4, 8 and 12 weeks after transplantation in the aspect of area and volume. What was more, results indicated that allograft BMSC-sheet had survivaled in the scaffold material and participated in the newly formed bone which had the same thickness with surrounding autologous bone tissues after transplantation. Results of our study demonstrated that CBB-BMSC-sheet combination was a promising strategy in healing of large area bone defect in osteoporosis.

  16. Reduction of Acute Inflammatory Effects of Fumed Silica Nanoparticles in the Lung by Adjusting Silanol Display through Calcination and Metal Doping.

    Science.gov (United States)

    Sun, Bingbing; Pokhrel, Suman; Dunphy, Darren R; Zhang, Haiyuan; Ji, Zhaoxia; Wang, Xiang; Wang, Meiying; Liao, Yu-Pei; Chang, Chong Hyun; Dong, Juyao; Li, Ruibin; Mädler, Lutz; Brinker, C Jeffrey; Nel, André E; Xia, Tian

    2015-09-22

    The production of pyrogenic (fumed) silica is increasing worldwide at a 7% annual growth rate, including expanded use in food, pharmaceuticals, and other industrial products. Synthetic amorphous silica, including fumed silica, has been generally recognized as safe for use in food products by the Food and Drug Administration. However, emerging evidence from experimental studies now suggests that fumed silica could be hazardous due to its siloxane ring structure, high silanol density, and "string-of-pearl-like" aggregate structure, which could combine to cause membrane disruption, generation of reactive oxygen species, pro-inflammatory effects, and liver fibrosis. Based on this structure-activity analysis (SAA), we investigated whether calcination and rehydration of fumed silica changes its hazard potential in the lung due to an effect on silanol density display. This analysis demonstrated that the accompanying change in surface reactivity could indeed impact cytokine production in macrophages and acute inflammation in the lung, in a manner that is dependent on siloxane ring reconstruction. Confirmation of this SAA in vivo, prompted us to consider safer design of fumed silica properties by titanium and aluminum doping (0-7%), using flame spray pyrolysis. Detailed characterization revealed that increased Ti and Al doping could reduce surface silanol density and expression of three-membered siloxane rings, leading to dose-dependent reduction in hydroxyl radical generation, membrane perturbation, potassium efflux, NLRP3 inflammasome activation, and cytotoxicity in THP-1 cells. The reduction of NLRP3 inflammasome activation was also confirmed in bone-marrow-derived macrophages. Ti doping, and to a lesser extent Al doping, also ameliorated acute pulmonary inflammation, demonstrating the possibility of a safer design approach for fumed silica, should that be required for specific use circumstances. PMID:26200133

  17. Microstructure and application study of secondary calcined lime as consolidant for cultural relics%“二次生石灰”的微结构及作为文物加固剂的应用研究

    Institute of Scientific and Technical Information of China (English)

    魏国锋; 张秉坚; 方世强; 姚政权

    2011-01-01

    在研究二次生石灰微结构的基础上,探讨了以二次生石灰为基础胶结材料用于古代建筑和土遗址加固保护的可行性.二次生石灰的SEM观察结果表明:氢氧化钙经高温(650℃)锻烧以后,脱水成为一种直径为50 nm、长度为200 nm左右的针状纳米氧化钙f将这种纳米氧化钙消化后,会成为一种粒径在200~300nm左右、大小十分均匀的扁平椭圆状纳米氢氧化钙颗粒.同时,研究表明,二次生石灰的纳米级粒径和高反应活性,可以提高二次生石灰糯米灰浆的机械性能,并使二次生石灰-乙醇分散液具有良好的渗透性,较好地解决了传统石灰水加固剂溶解度较小和渗透性较差的问题,从而为士石砖等不可移动文物的基于传统石灰的加固技术提供了新的途径.%On the basis of study on microstructure of secondary calcined lime, this paper probes into applications of secondary calcined lime in conservation of cultural relics. SEM observations show that Ca(OH)2 is transformed into a kind of ac-icular CaO with diameter 50 nm and length 200 nm after being calcined, and this nanosized secondary CaO is transformed into an oval platelike Ca(OH)2 with size 200-300 nm after slaked. Meanwhile, research results indicate that nanosized particles and high reactivity of secondary calcined lime are responsible for superior properties of sticky rice-lime mortar and high permeability of Ca(OH)2-alcohol dispersions, and it is feasible that secondary calcined lime is used for consolidation of soil, stone and brick-based cultural heritage.

  18. Fall 2010 Semiannual (III.H. and I.U.) Report for the HWMA/RCRA Post Closure Permit for the INTEC Waste Calcining Facility and the CPP 601/627/640 Facility at the INL Site

    Energy Technology Data Exchange (ETDEWEB)

    Boehmer, Ann

    2010-11-01

    The Waste Calcining Facility is located at the Idaho Nuclear Technology and Engineering Center. In 1999, the Waste Calcining Facility was closed under an approved Hazardous Waste Management Act/Resource Conservation and Recovery Act (HWMA/RCRA) Closure Plan. Vessels and spaces were grouted and then covered with a concrete cap. The Idaho Department of Environmental Quality issued a final HWMA/RCRA post-closure permit on September 15, 2003, with an effective date of October 16, 2003. This permit sets forth procedural requirements for groundwater characterization and monitoring, maintenance, and inspections of the Waste Calcining Facility to ensure continued protection of human health and the environment. The post closure permit also includes semiannual reporting requirements under Permit Conditions III.H. and I.U. These reporting requirements have been combined into this single semiannual report, as agreed between the Idaho Cleanup Project and Idaho Department of Environmental Quality. The Permit Condition III.H. portion of this report includes a description and the results of field methods associated with groundwater monitoring of the Waste Calcining Facility. Analytical results from groundwater sampling, results of inspections and maintenance of monitoring wells in the Waste Calcining Facility groundwater monitoring network, and results of inspections of the concrete cap are summarized. The Permit Condition I.U. portion of this report includes noncompliances not otherwise required to be reported under Permit Condition I.R. (advance notice of planned changes to facility activity which may result in a noncompliance) or Permit Condition I.T. (reporting of noncompliances which may endanger human health or the environment). This report also provides groundwater sampling results for wells that were installed and monitored as part of the Phase 1 post-closure period of the landfill closure components in accordance with HWMA/RCRA Landfill Closure Plan for the CPP-601 Deep

  19. 煅烧磷石膏对蒸压硅酸盐制品水化过程的影响%Effect of calcined phosphogypsum on hydration process of autoclaved silicate products

    Institute of Scientific and Technical Information of China (English)

    陆金驰; 李东南; 陈凯; 黄金林

    2012-01-01

    磷石膏经高温煅烧改性后与粉煤灰、砂粉、石灰及水泥熟料等制备蒸压硅酸盐制品,研究了不同温度煅烧的磷石膏对蒸压硅酸盐制品水化过程的影响,用蒸压制品中未反应的Ca(OH)2量及结合水量分析它们的反应速率,用XRD测定蒸压硅酸盐制品的水化产物,并结合SEM分析,结果表明,经煅烧的磷石膏对蒸压硅酸盐制品的水化有明显的促进作用,托勃莫来石与C-S-H (1)等水化产物的迅速生长而形成密实的水化产物结构是其增强蒸压硅酸盐制品的根本原因.%The effects of calcined phosphogypsum on the hydration process of the autoclaved silicate products were investigated in this paper. The influence of adding phosphogypsum calcined at different temperatures on the hydration rate of autoclaved silicate products was analyzed for un-reacted Ca(OH)2 content and combined water. The hydrates were determined with XRD and SEM. It was found that the hydration of autoclaved silicate products with added phosphogypsum calcined over 500℃ was greatly improved. The hydrates of the autoclaved silicate products with added phosphogypsum calcined over 500℃ had more un-reacted Ca(OH)2 content and combined water in the same curing time, and the research indicated that adding phosphogypsum calcined over 500℃ could also reinforce the compressive strength of autoclaved silicate products. It was pointed out that the aluminate phase present in the raw materials cannot hydrate to form more ettringite during autoclaved curing, and rapid formation of such hydrates as calcium silicate hydrate (1) and tobermorite with a more compact structure is the main reason for strengthening autoclaved silicate products.

  20. Research of Magnesium Extracted from Asbestos Tailings by Ammonium Sulfate Calcination Method%硫酸铵焙烧活化石棉尾矿提取镁实验研究

    Institute of Scientific and Technical Information of China (English)

    曾丽; 孙红娟; 彭同江

    2012-01-01

    本实验采用硫酸铵与石棉尾矿用高温炉焙烧的方法提取镁.首先利用差热-热重法分析石棉尾矿与硫酸铵混合物的热分解和化学反应的热效应,得出石棉尾矿与硫酸铵混合物在240~ 500℃下产生分解、失重.将石棉尾矿与硫酸铵混合均匀后在320℃、400℃和460℃下焙烧1h,用XRD分析焙烧产物,得出在320℃时石棉尾矿和硫酸铵反应主要生成(NH4)2Mg(SO4)2和(NH4)2Mg2(SO4)3;在400℃时主要生成(NH4)2Mg2(SO4)3;在460℃时主要生成MgSO4,由于吸水变为MgSO4·6H2O.研究了硫酸铵与石棉尾矿不同物质的量的配比、焙烧温度和焙烧时间对镁浸取率的影响,得出当硫酸铵与石棉尾矿物质的量之比为2∶1、焙烧温度为460℃、焙烧时间为60 min时,镁的浸取率为83.1%.%In this paper, magnesium was extracted from asbestos tailings by ammonium sulfate calcination method. First the thermal behavior and the chemical calorific effect of the blend of asbestos tailings and ammonium sulfate were characterized by TG-DTA, it showed that asbestos tailings and ammonium sulfate were decompounded at 240~500 ℃. Then the asbestos tailings were uniform mixed with ammonium sulfate and calcined at 320 ℃, 400 ℃, and 460 ℃ for 1 h respectively and the calcinated products were studied by XRD. The results indicated that asbestos tailings and ammonium sulfate react each other to generate (NH4)2Mg(SO4)2 and (NH4)2Mg2(SO4)3 at 320 °C; the main product was (NH4)2Mg2(SO4)3 at 400 ℃ and MgSO4 at 460℃ respectively. Then the influence of the molar ratio of ammonium sulfate and asbestos tailings, the calcination temperature, the calcination time were studied. The results indicated that when the molar ratio of ammonium sulfate and asbestos tailings is 2 : 1, the calcination temperature is 460 ℃, the calcination time is 60 min, the leaching rate of Mg is 83.1%.

  1. Conditioning of HLW-calcines

    International Nuclear Information System (INIS)

    Our program on waste conditioning alternatives includes the study of coatings of simulated highly radioactive waste granules with nickel. From pyrolytical decomposed nickeltetracarbonyl nickel was deposited by chemical vapor deposition in a fluidized bed. Advantages of this method are the low coating temperatures (at about 470 K), at which suitable coatings could obtained by a special adaption of the performance. Pure nickel layers were deposited, of which the tightness, thickness, mechanical stability, crystallite size and its characterization in optical and microoptical examinations were tested. The results of the quality control showed a remarkable increase in mechanical stability, leach resistance and thermal conductivity of the coated waste granules. Therefore the obtained ductile and well adherent nickel-coatings are preferably applicable as one of protective shells in a multibarrier waste concept. (author)

  2. Preparation of superfine and sheet magnesium hydroxide from calcined magnesite%轻烧镁粉制备超细片状氢氧化镁

    Institute of Scientific and Technical Information of China (English)

    汪艳; 王伟; 张俊; 胡珊

    2013-01-01

    The superfine and sheet magnesium hydroxide was preparaed by direct precipitation method, using the calcined magnesite as magnesium source and ammonia as agent precipitation. The influence of magnesium hydroxide' s average particle size with the relationship of different reaction conditions by particle size tester was studied. And then the best process conditions of the synthesis of magnesium hydroxide was got. The product was verified for magnesium hydroxide by X-ray diffraction, scanning electron microscope,thermo-gravimetric analysis and infrared spectromete. At last, the best synthesis condition was got. The influence of surfactant to magnesium hydroxide was researched. The results show that the experiment product is superfine and sheet magnesium hydroxide; the best synthetic process conditions are of 40 ℃ reaction temperature, reaction time of h 1. 5, ammonia water dosage of 170 mL and adding speed of 12 mL/min; the anionic surfactant-SDBS can effectively improve the dispersion and morphology of magnesium hydroxide.%以轻烧镁粉为镁源,氨水为沉淀剂,采用直接沉淀法制备超细片状氢氧化镁.通过粒度测试仪研究了不同反应条件对氢氧化镁平均粒径的影响,最终得到合成氢氧化镁的最佳工艺条件.利用X射线衍射、热失重分析、扫描电子显微镜和红外光谱仪对产物氢氧化镁进行了表征.分析了表面活性剂对制备氢氧化镁的影响.结果表明:实验所得产物为超细氢氧化镁,且晶体比较完善,形貌为六方片状.最佳合成工艺条件为反应温度40℃、反应时间1.5h、氨水的用量和滴加速度分别为170 mL和12 mL/min;添加阴离子表面活性剂十二烷基苯磺酸钠能有效改善氢氧化镁的分散性和形貌.

  3. Mixed Silica Titania Materials Prepared from a Single-Source Sol-Gel Precursor: A Time-Resolved SAXS Study of the Gelation, Aging, Supercritical Drying, and Calcination Processes

    OpenAIRE

    Torma, V.; Peterlik, N. A.; Bauer, U; Rupp, W.; Hüsing, N; Bernstorff, S.; Steinhart, M.; Goerigk, G.; Schubert, U

    2005-01-01

    The morphology of gels prepared from a silica/titania single-source precursor (1), obtained by reaction of 3-oxoethyl-6-trimethoxysilyl-hexan-2-one with Ti((OPr)-Pr-i)(4), was investigated by small-angle X-ray scattering (SAXS) through all stages of the preparation process, that is, gelation, aging, drying, and calcination. The same investigations were performed for mixtures of 1 and Si(OEt)(4). Immediately after the start of the reaction small primary particles are formed, the size of which ...

  4. 钙基吸收剂循环煅烧/碳酸化反应特性%Characteristics of Cyclic Calcination/Carbonation Reaction of Ca-based Absorbent

    Institute of Scientific and Technical Information of China (English)

    赵士林; 刘浩; 夏雯; 吴昊; 杨宏旻

    2013-01-01

    Aiming at the effects of cycle number,absorbent particle size,CO2 concentration in calcinations,carbonation atmosphere and water vapour concentration on characteristics of cyclic calcination/carbonation reaction of Ca-based absorbent,they are investigated experimentally on a lab-scale setup. The results show that the carbonation conversion of Ca-based absorbent decreases from 72% to 30% after 10 cycles in the calcination/carbonation reaction. The small particle size can improve the carbonation conversion of absorbent. The increase of CO2 concentration in carbonation atmosphere can restrain the decrease of conversion rate in carbonation process. The increase of CO2 concentration in calcination atmosphere can accelerate the decrease of the conversion rate in carbonation conversion process,which results in the decrease of cycle performance for CO2 capture. Water vapour reduces the energy barrier of the diffusion across the solid production,which prolongs carbonation reaction time and increases conversion rate.%针对循环次数、吸收剂粒径的大小、碳酸化气氛中CO2的浓度、煅烧气氛中CO2的浓度和水蒸气的浓度对于钙基吸收剂循环煅烧/碳酸化反应特性的影响,在钙基吸收剂循环煅烧/碳酸化反应实验装置上进行实验研究。结果表明:钙基吸收剂碳酸化阶段的转化率在循环煅烧/碳酸化反应中存在衰减现象,10次循环反应之后,转化率会从72%降至30%以下;吸收剂碳酸化阶段的转化率随其粒径的增大而减小;碳酸化气氛中CO2浓度的提高,会抑制钙基吸收剂碳酸化阶段转化率的衰减;煅烧气氛中CO2浓度的增加会加速钙基吸收剂碳酸化阶段转化率的衰减,导致循环捕集CO2性能锐减;水蒸气能降低固体产物扩散的能量壁垒,延长碳酸化反应时间,提高转化率。

  5. Scientific Opinion on the safety assessment of the active substances iron powder, activated carbon, calcined kaolin, sodium chloride, polyacrylic acid, sodium salt, crosslinked and calcium chloride, for use as active system in food contact materials

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF

    2014-05-01

    Full Text Available This scientific opinion of the EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids deals with the safety assessment of the active substances iron powder, activated carbon, calcined kaolin, sodium chloride, polyacrylic acid, sodium salt, crosslinked and calcium chloride, used in mixture which is packed into labels, for absorbing oxygen from the headspace surrounding packed food. All substances of this formulation have been evaluated and approved for use as additives in plastic food contact materials or as food supplements. Migration of substances from the labels and formation and release of volatile constituents are not expected under the intended conditions of use. The CEF Panel concluded that the use of substances iron powder, activated carbon, calcined kaolin, sodium chloride, polyacrylic acid, sodium salt, crosslinked and calcium chloride does not raise a safety concern when used in oxygen absorbers in labels, which prevent the physical release of their content into the food. When placed in the headspace of the packaging or when used in direct contact with foods, the labels should not intentionally or unintentionally come into direct contact with liquid foods or foods that have an external aqueous phase on the surface such as sliced fruits.

  6. Effect and mechanism of calcination temperature on reduction swelling rate of low silica magnesium pellets%焙烧温度对低硅含镁球团矿还原膨胀率的影响及机理

    Institute of Scientific and Technical Information of China (English)

    青格勒; 吴铿; 刘洪松; 员晓; 田筠清

    2015-01-01

    研究焙烧温度对MgO含量分别为1.5%和3.0%(质量分数)的低硅含镁球团的抗压强度、矿相和还原膨胀率的影响,并基于 Arrhenius 方程和还原度测定计算低硅含镁球团还原反应的表观活化能,分析还原反应的速率限制性环节。结果表明:当焙烧温度较低时,低硅含镁球团内形成的铁酸镁数量较少,存在未反应的MgO颗粒,其还原过程主要受气体扩散和界面化学反应混合控制,还原膨胀率高,还原后强度低。1280℃高温下,焙烧的低硅含镁球团形成的铁酸镁数量多、强度高,还原过程后期主要受固相扩散即铁离子扩散控制,尤其是低硅高镁球团受固相扩散控制更明显,还原过程中未出现针状铁晶粒,还原膨胀率低。%The compressive strength, microstructure and reduction swelling rate of low silica magnesium pellets with 1.5%MgO and 3.0%MgO (mass fraction) calcinated at different temperatures were studied. Apparent activation energy of low silica magnesium pellets calcinated at different temperatures was also obtained by Arrhenius formula and reduction test. The rate controlling mechanism of reduction reaction was determined from apparent activation energy together. The results show that, when the calcination temperature is low, few magnesium ferrites form in low silica magnesium pellets and unreacted MgO exists, and the reduction process is controlled mainly by gas diffusion and interfacial chemical reaction, which results in high reduction swelling rate and deteriorates the strength. While calcination temperature increases to 1280℃, there forms large amount of magnesium ferrites in pellets and the compressive strength of pellets increase significantly. Later stage of reduction reaction of low silica magnesium pellets (specially the pellets with 3.0%MgO) calcinated at high temperature is mainly controlled by solid diffusion, that is ferric ion solid diffusion, so almost no iron whiskers

  7. Resource Recovery of Magnesium Saponification Wastewater of Leaching Solution of Sulfuric Acid Calcining RE Concentrate%浓硫酸高温焙烧稀土精矿水浸液镁皂化废水的资源化

    Institute of Scientific and Technical Information of China (English)

    刘磊; 谢军; 李赫; 柳凌云; 侯少春; 萨如拉; 姚龙君

    2015-01-01

    研究了包头稀土精矿浓硫酸高温焙砂水浸液经过镁皂化萃取转型产生的镁皂废水的资源化全循环工艺,针对镁皂废水的净化除杂、晶体制备、晶体煅烧等进行了可行性研究。结果表明:控制草酸用量为理论量的2倍,镁皂废水的氧化钙质量浓度<0.2g/L ;净化后的镁皂废水经陶瓷膜过滤、纳滤膜浓缩得到的透析水可回用于水浸,浓水进入蒸发系统回收硫酸镁和冷凝水;冷凝水回用于水浸,硫酸镁晶体与碳粉在850℃下煅烧8 h可制备氧化镁;所得氧化镁的 CAA 活性值为109 s ,MgO 质量分数为96.84%,CaO 质量分数为0.52%,可用于生产稀土;硫酸镁煅烧产生的二氧化硫在钒触媒催化作用下可转化成70%的硫酸,回用于焙烧。该工艺可实现镁皂废水资源化全循环利用。%The resource recovery of magnesium saponification wastewater of leaching solution of sulfuric acid calcining rare earth concentrate was studied mainly involving the progresses of purification ,crystallization ,calcination and so on .T he experiment results show w hen the actual amount of oxalic acid is twice the theoretical amount ,the content of CaO in the magnesium saponification wastewater can be reduced to less than 2% .Then the dialysis water by ceramic membrane and nanofiltration membrane can be used in the process of RE leaching ,and the concentrate water can be used to recover magnesium sulfate and condensate water in evaporation system .The condensate water can used in the process of RE leaching .The magnesium sulfate crystal with carbon powder is calcinated for 8 h at 850 ℃ ,the magnesium oxide can be obtained .The analysis results show that in the magnesium oxide ,the content of MgO and CaO is 96 .84% and 0 .52% ,respectively .The value of CAA for the magnesium oxide is 109 s .Sulfur dioxide produced in the process of calcination can be conversed into 70% sulfuric acid used in the process

  8. Tailored temperature window of CuO{sub x}/WO{sub x}–ZrO{sub 2} for NO{sub x} reduction via adjusting the calcination temperature of WO{sub x}–ZrO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Si, Zhichun, E-mail: si.zhichun@sz.tsinghua.edu.cn [Advanced Materials Institute, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Wu, Xiaodong [State Key Laboratory of New Ceramics and Fine Process, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Yangtze Delta Region Institute of Tsinghua University, Zhejiang 314000 (China); Weng, Duan, E-mail: duanweng@tsinghua.edu.cn [State Key Laboratory of New Ceramics and Fine Process, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Ma, Ziran; Ma, Jing [State Key Laboratory of New Ceramics and Fine Process, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2013-02-15

    WO{sub x}–ZrO{sub 2} support was calcined at various temperatures for obtaining controllable activity of copper catalysts for NO{sub x} reduction by ammonia. The temperature window of copper catalyst for over 80% NO{sub x} conversion shifts from 180–300 to 230–350 °C by elevating the calcination temperature of WO{sub x}–ZrO{sub 2} support from 500 to 600 °C, due to the increased Brønsted acidity and reduced structure and electronic interactions between copper oxides and tungsten oxides arising from the polymerization of WO{sub x} clusters on surface of support. Calcining WO{sub x}–ZrO{sub 2} support at 700 °C leads to the reduced redox property of copper oxides on the Cu–O–W interface and the formation of bulk-like CuO, results in a low activity of catalyst. - Graphical abstract: The temperature window of catalyst for over 80% NO{sub x} conversion shifts from 180-300 °C to 230–350 °C by elevating the calcination temperature of WO{sub x}–ZrO{sub 2} support from 500 °C to 600 °C. Highlights: ► The temperature window of catalyst is tailored by calcining the support. ► The mechanisms of tailoring the temperature window of catalyst are discussed. ► The polymerization of WO{sub x} leads to the increased Brønsted acidity of catalysts. ► The CuO{sub x}/WO{sub x} interactions are reduced by elevating calcination temperature of support.

  9. Effect of calcination temperature on the structure and visible-light photocatalytic activities of (N, S and C) co-doped TiO{sub 2} nano-materials

    Energy Technology Data Exchange (ETDEWEB)

    Lei, X.F., E-mail: leixuefei69@163.com [School of Resources and Materials, Northeastern University at Qinhuangdao, Qinhuangdao 066004 (China); Institute of Metallurgical Resource and Environmental Engineering, Northeastern University, Shenyang 110819 (China); Liaoning Key Laboratory of Metallurgical Resource Recycling Science, Shenyang 110819 (China); Liaoning Engineering and Technology Research Center of Boron Resource, Comprehensive Utilization, Shenyang 110819 (China); Liaoning Provincial Universities Key Laboratory of Boron Resource Ecological, Utilization Technology and Boron Materials, Shenyang 110819 (China); Xue, X.X.; Yang, H. [Institute of Metallurgical Resource and Environmental Engineering, Northeastern University, Shenyang 110819 (China); Liaoning Key Laboratory of Metallurgical Resource Recycling Science, Shenyang 110819 (China); Liaoning Engineering and Technology Research Center of Boron Resource, Comprehensive Utilization, Shenyang 110819 (China); Liaoning Provincial Universities Key Laboratory of Boron Resource Ecological, Utilization Technology and Boron Materials, Shenyang 110819 (China); Chen, C.; Li, X.; Niu, M.C.; Gao, X.Y.; Yang, Y.T. [School of Resources and Materials, Northeastern University at Qinhuangdao, Qinhuangdao 066004 (China)

    2015-03-30

    Graphical abstract: (N, S and C) co-doped TiO{sub 2} samples show good photocatalytic activity for Cr(VI) reduction under visible light irradiation. - Highlights: • (N, S and C) co-doping in TiO{sub 2} can preserve the anatase form to higher temperature. • (N, S and C) co-doped TiO{sub 2} samples can absorb both UV and visible light. • The band gap energy of the sample significantly reduced after (N, S and C) co-doping. • (N, S and C) co-doped TiO{sub 2} samples effective for visible light induced reduction of Cr(VI). - Abstract: The (N, S and C) co-doped TiO{sub 2} samples (NSC-TiO{sub 2}) were synthesized by the sol–gel method combining with the high energy ball milling method calcined at the different temperature (400–700 °C), employing butyl titanate as the titanium source and thiourea as the doping agent. The structures of NSC-TiO{sub 2} samples were characterized by X-ray diffraction (XRD), UV–vis diffuse reflectance spectra (DRS), X-ray photoluminescence (PL) spectroscopy, X-ray photoelectron spectroscopy (XPS), thermogravimetry and differential thermal analysis (TG–DTA), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscope (TEM), scanning electron microscopy (SEM) and nitrogen adsorption–desorption isotherms. The photocatalytic activities were checked through the photocatalytic reduction of Cr(VI) as a model compound under visible light irradiation. The results showed that the (N, S and C) co-doping and the calcination temperature played important role on the microstructure and photocatalytic activity of the samples. According to XPS spectra, sulfur was mainly attributed to the Ti−O−S bond; nitrogen was ascribed to the Ti−O−N and Ti−N bonds; carbon was assigned to the Ti−O−C bond in the NSC-TiO{sub 2} samples. (N, S and C) co-doped TiO{sub 2} samples calcinated at 500 °C exhibits higher photocatalytic activity than that of the other samples under visible light irradiation, which can be

  10. Enhanced photocatalytic activity for the degradation of rhodamine B by TiO{sub 2} modified with Gd{sub 2}O{sub 3} calcined at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jing, E-mail: jingzhang_dicp@live.cn [College of Chemistry, Chemical Engineering and Environmental Engineering, Liaoning Shihua University, Liaoning 113001 (China); Wu, Weicheng; Yan, Song; Chu, Gang; Zhao, Shanlin [College of Chemistry, Chemical Engineering and Environmental Engineering, Liaoning Shihua University, Liaoning 113001 (China); Wang, Xiang; Li, Can [State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning (China)

    2015-07-30

    Graphical abstract: Surface modification with Gd{sub 2}O{sub 3} can control the surface crystalline phase, crystallinity, and crystal size (surface area) of TiO{sub 2} calcined at high temperatures. The results from photocatalytic degradation of rhodamine B show that upon calcination at high temperature the Gd/TiO{sub 2} exhibits higher photocatalytic activity than TiO{sub 2}. The higher photocatalytic activity of Gd/TiO{sub 2} is mainly attributed to an increase in photoinduced charge separation due to the formation of phase junction between anatase and rutile stabilized by surface Gd{sub 2}O{sub 3}. - Highlights: • The crystalline phase in the surface region of TiO Gd. • The surface-phase junctions formed between anatase and rutile, together with the high crystallinity of TiO. - Abstract: TiO{sub 2} modified with Gd{sub 2}O{sub 3} (Gd/TiO{sub 2}) nanoparticles were prepared by an impregnation method using TiO{sub 2}-500 °C support (anantase phase) or TiO{sub 2}-650 °C support (mixed phases of anatase and rutile), respectively. The surface and bulk crystalline phases of Gd/TiO{sub 2} have been characterized by UV Raman spectroscopy and XRD. Besides, the morphology, particle size, and the optical properties of Gd/TiO{sub 2} have been studied by TEM, BET, and UV–visible diffuse reflectance spectra. It is interesting to note that the surface crystalline phase (surface anatase phase or surface mixed phases) of TiO{sub 2} which has been impregnated with Gd{sub 2}O{sub 3} can be stabilized after calcination at 800 °C. This work provides a promising method for controlling the surface phase, crystallinity, and particle size of TiO{sub 2} at high temperatures. Moreover, photocatalytic activity of Gd/TiO{sub 2} has been evaluated by degradation of rhodamine B and 4-chlorophenol in aqueous solution under UV irradiation. It is found that Gd/TiO{sub 2} exhibits good photocatalytic activity compared to pure TiO{sub 2}. The higher photocatalytic activity of Gd/TiO{sub 2

  11. 从闪速还原锌焙砂中选择性浸出锌、铁试验研究%Selective Acid Leaching of Zinc and Iron From Flash Reduction Zinc Calcine

    Institute of Scientific and Technical Information of China (English)

    戴曦; 陈田庄; 吴永谦; 周康洁; 李良斌

    2013-01-01

    Selective acid leaching of zinc and iron from flash reduction roasting product was studied .The influence of initial sulfuric acid concentration ,leaching temperature ,leaching time ,the ratio between liquid volume and solid mass ,stirring rate on leaching of zinc and iron were studied .The results show that the leaching rate of zinc increases more than 10% after zinc calcine being reduction roasted ,iron content in the leaching residue increases more than 7% .The leaching as well as filtering performance are improved due to the porous structure of reduction zinc calcine .The formation of the desired magnetic compound Fe3 O4 by efficient decomposition of ZnFe2 O4 in zinc calcine is effective to separate zinc and iron .%研究了从锌焙砂闪速还原焙烧产物中选择性酸浸锌,考察了初始硫酸质量浓度、浸出温度、浸出时间、液固体积质量比、搅拌速度对锌、铁浸出率的影响。试验结果表明:还原锌焙砂的锌浸出率较锌焙砂的锌浸出率提高10%以上,其浸出渣中含铁质量分数提高7%以上;还原锌焙砂结构疏松多孔,使其及浸出渣的过滤性能得以改善。高效分解锌焙砂中ZnFe2 O4并形成理想形态的磁性化合物Fe3 O4,是提高还原锌焙砂锌浸出率并抑制铁浸出从而实现锌、铁有效分离的关键。

  12. 焙烧大理石粉处理工业含磷废水的试验研究%Study on Removing Phosphorus from Phosphorus-Containing Industrial Wastewater Using Calcined Marble Powder

    Institute of Scientific and Technical Information of China (English)

    陈璧瑕; 漆辉; 孟晓霞; 伍钧; 唐骁

    2011-01-01

    本文研究了焙烧大理石粉处理工业含磷废水的除磷效果。探讨了不同焙烧大理石粉投加量、反应时间、反应温度以及振荡速率对除磷效果的影响。结果表明:焙烧大理石粉的投加量和反应时间是影响除磷效果的主要因素。当焙烧大理石粉投加量为11g/L,反应时间为10min左右,温度为室温,振荡速率保持在100~150r/min时,废水中磷的去除率达到最高,约为99.91%,余磷浓度为0.16~0.24mg/L,小于《污水综合排放标准》(GB8978-1996)的一级标准。%This paper studied the dephosphorization performance of the phosphorus wastewater treatment using calcined marble powders.The effects of different factors such as calcined marble powder dosages,reaction time elapsed,reaction temperatures and oscillation rates were studied.The results showed that the dosage of calcined marble powder was the most significant factor affecting the phosphorus removals.The optimum conditions were dosage of 11 g/L,reaction time of about 11 minutes,room temperature and oscillation rate of 100~150 r/min,when the removal rate of phosphorus reached the maximum,99.91%,and the residual concentration of phosphorus was 0.16~0.24 mg/L,all lower that the Grade I standard of Integrated Wastewater Discharge Standard(GB8978-1996).

  13. Avaliação de erosão a quente de concretos refratários para calcinadores de leito fluidizado Hot erosion evaluation of fluid flash calciner refractory castables

    Directory of Open Access Journals (Sweden)

    L. R. G. Gonçalves

    2011-06-01

    Full Text Available Revestimentos refratários são severamente solicitados pela erosão causada por partículas que se movem pneumaticamente através de vasos e dutos em calcinadores de leito fluidizado. Esse tipo de desgaste constitui um fator chave para a degradação do revestimento desse equipamento. Consequentemente, o desempenho desses refratários tem um efeito imediato no lucro da empresa, uma vez que paradas para reparos tem um impacto direto no cronograma operacional e nos custos de manutenção da unidade produtiva. Apesar da temperatura de operação dos calcinadores variar entre 200 e 1250 ºC, a resistência a erosão, que é uma das principais propriedades selecionadas para avaliar materiais usados nessa aplicação, geralmente é medida somente à temperatura ambiente. Porém, esse tipo de avaliação não representa fielmente as condições de operação. Portanto, é necessário um estudo mais realista na tentativa de encontrar alguma relação entre a severidade de erosão e a temperatura. Visando alcançar esse objetivo, o presente trabalho apresenta o desenvolvimento e aplicação de um equipamento de erosão à quente para avaliação de concretos refratários para calcinadores de leito fluidizado.Refractory linings are heavily damaged by the erosion caused by particles moving pneumatically through vessels and pipes in fluid flash calciners. This sort of wearing constitutes one of the key factors for equipment lining degradation. Consequently, the performance of materials has an immediate effect on a company's profit, as each maintenance call has a direct impact on the operational schedule and costs. Although the operation temperature of the calciners ranges from 200 up to 1250 ºC, the erosion resistance, which is one of the main properties selected to evaluate the materials used in this application, is mostly measured only at room temperature. Nevertheless, this sort of evaluation does not represent the actual working environment. Therefore

  14. Caracterização de concretos refratários projetáveis para o revestimento de calcinadores de alumina Characterization of alumina fluid-flash calciner refractory castable lining

    Directory of Open Access Journals (Sweden)

    F. A. O. Valenzuela

    2008-03-01

    Full Text Available Diversos fatores interferem no desempenho e na vida-útil do revestimento refratário em unidades de calcinação de alumina. O desconhecimento das melhores práticas de seleção e qualificação dos materiais para esta aplicação foi a força motriz para este trabalho. Foram caracterizados dois materiais comerciais aplicados por projeção (um via wet-shotcrete e outro por dry-gunning, indicados para o revestimento refratário dos vasos e dutos de calcinadores de alumina. Tais técnicas são importantes, uma vez que reduzem o tempo de aplicação e o lucro cessante da unidade. Os materiais em análise foram submetidos a baterias de testes laboratoriais, os quais seguem normas técnicas internacionais. Os ensaios foram divididos segundo a representatividade das solicitações que ocorrem no revestimento em operação, e os resultados obtidos foram usados para avaliar o seu potencial desempenho. O embasamento técnico e científico utilizado neste trabalho pôde orientar o desenvolvimento, a seleção e a aplicação de novas cerâmicas refratárias para o revestimento interno de calcinadores, com o objetivo de elevar a vida-útil, a disponibilidade e a confiabilidade das unidades, possibilitando diminuir o custo com manutenções.Several aspects are important to define the working life of refractory lining for alumina calcinations units. The lack of knowledge of the best selection practices and qualification of the materials for this application have been the driving force of this work. Two commercial materials applied by projection (wet-shotcrete and dry-gunning were characterized. Both are usual standards of refractories for lining vessels and pipes of alumina fluid-flash calciners. All the materials analyzed were submitted to laboratorial tests, which follow international technical standards. The tests were divided in indispensable, necessary and occasional, according to the importance of the solicitations of the refractory lining under

  15. Influence of cobalt nitrate concentration in the calcination temperature and time for synthesis of La0,60Sr0,40Co0,20Fe0,80O3

    International Nuclear Information System (INIS)

    The La(1-x)SrxCo(1-y)FeyO3 (LSCF) has been highlighted as a excellent cathode for Intermediate Temperature Solid Oxide Fuel Cells, due to the high catalytic activity and good ionic and electronic conductivity. This work presents some characteristics of LSCF particle with regard of nitrate excess cobalt influence in the synthesis which different temperatures (700, 800, 900 and 1000 deg C) and times (2, 3 and 4h) calcination. The material was synthesized by citrate technique and analysis for XRF to confirmed the formation of nominal composition (x=0,40 and y=0,80). The micrographs showed the grain sized distribution disclosed particle accumulations, with 0,50 mum inferior average sizes. It was verified for TGA that the LSCF is synthesized above at 700 deg C and for XRD the studied formation of the main phase pseudo-orthorhombic structure in temperatures and times studied.(author)

  16. EFFECT OF CALCINATION TEMPERATURE ON NIMOS HYDROCRACKING CATALYST CONTAINING SULFUR PRECURSORS%焙烧温度对含硫前体NiMOS加氢裂化催化剂反应性能的影响

    Institute of Scientific and Technical Information of China (English)

    姜艳; 王继锋; 孙晓艳; 王少军

    2011-01-01

    NiMoS hydrocracking catalysts containing sulfur precursors calcined under various temperatures were prepared by kneading method,using ammonium tetrathiomolybdate and nickel nitrate as active components, and composite support composed of γ-Al2O3 and modified zeolite Y.The properties of catalysts were investigated by FT-IR, XRD and TEM.Test results indicated that with the increase of calcination temperature,the total acidity of the catalysts with sulfur precursors increased firstly and then decreased; more medium strong acid amount and higher B/L value were observed for these catalysts as compared with the oxidation state catalyst.The interactions between metal component and support in the catalysts containing ammonium tetrathiomolybdate as sulfur precursor were weakened, thus suitable crystal sizes and stacking numbers of active metal components could be obtained and the catalytic performances of the catalysts were improved.However, exceeded high calcination temperature was not in favor of forming suitable average crystal size and stacking number of MoS2 active phase.Catalyst with sulfur precursors calcined at 500 ℃ exhibited good hydrocracking performance: high conversion and liquid yield,as well as high selectivity and outstanding isomerization performance.%采用四硫代钼酸铵、硝酸镍为活性组分,从γ-Al2O3和改性Y分子筛的混合物为载体,通过混捏法制备不同焙烧温度的含硫前体NiMoS加氢裂化催化剂.对催化剂进行IR,TEM,XRD表征.结果表明:随焙烧温度的升高,含硫前体催化剂表面总酸量先增加后减小;含硫前体催化剂的中强酸酸量较大,且B酸量与L酸量之比也较大;由于以四硫代钼酸铵为前体的催化剂减少了金属与载体间的相互作用,有利于得到较佳的活性组分晶体尺寸和层数,从而提高了催化剂的性能;过高的焙烧温度不利于含硫前体催化剂活性相MoS2片晶形成合适的平均长度和平均层数;采用500℃焙烧的含

  17. Zinc recovery from zinc calcine by selective reduction roasting and acid leaching%锌焙砂的选择性还原焙烧硫酸浸出工艺研究

    Institute of Scientific and Technical Information of China (English)

    侯栋科; 彭兵; 柴立元; 彭宁; 闫缓; 胡明

    2014-01-01

    Zinc recovery from zinc calcine containing high content of iron by selective reduction roasting and acid leaching was investigated. Zinc ferrite in zinc calcine was selectively transformed to zinc oxide and magnetite under CO and CO2 atmosphere. The reduced zinc calcine was then leached with sulfuric acid for dissolving the soluble zinc in the leaching solution and leaving the iron in the residue as magnetite. The effects of reaction parameters of reduction roasting and sulfuric acid leaching on the recovery of zinc were studied and the reduced sample was analyzed by chemical analysis, XRD and SEM-EDS. Using the content of soluble zinc and ferrous iron as the evaluation index of the reduction roasting, the optimum conditions were obtained as follows: roasting temperature (750 ℃), roasting time (60 min), CO concentration (8 %) and CO/(CO+CO2) ratio (20 %). Under the optimum conditions, the content of soluble zinc in zinc calcine increased from 79.64 % to 91.75 %. With the leaching efficiency of zinc and iron as the evaluation index of the acid leaching, the best leaching conditions were obtained as follows:leaching temperature (normal temperature), leaching time (30 min), sulfuric acid concentration (90 g/L) and liquid to solid ratio (10∶1). The leaching efficiency of zinc and iron under this condition is 91.8%and 7.17%, respectively.%研究了选择性还原焙烧-硫酸浸出两段工艺处理高铁锌焙砂的方法.首先在CO还原气氛下将锌焙砂中的铁酸锌选择性转化为氧化锌和磁铁矿,然后采用硫酸浸出使可溶锌溶出而铁存留于渣中,实现铁锌有效分离.主要考察了还原焙烧以及硫酸浸出的工艺条件对铁锌分离效果的影响,并采用化学分析法及XRD、SEM-EDS的检测手段对焙烧样品进行分析.以可溶性锌和亚铁的含量作为焙烧评价指标,得出最佳焙烧条件为:焙烧温度750℃,焙烧时间60 min,CO浓度8%,CO/(CO+CO2)气氛比例20%,此条件下

  18. Improvement of existing solidification procedures for radioactive wastes from nuclear power plants. Trial operation of the MESA-3 line calciner at the Dukovany nuclear power plant on an active scale

    International Nuclear Information System (INIS)

    Experience gained at the Dukovany nuclear power plant since 1986 during the experimental operation of the prototype calciner of the MESA-3 line is summarized. Particular attention is paid to the period from the early 1988, when the so-called D-1 (real) concentrate from the OTW B 05 tank of this power plant was processed on this line. Adaptations of the line were currently made to eliminate shortcomings observed during the operation, and proposals for additional changes were accepted. This experience from the virtually uninterrupted operation and from experiments performed during shutdowns help to prepare and test a reliable version of the equipment, designed for use at other Czechoslovak nuclear power plants, at Temelin in particular. (author). 6 tabs., 20 refs

  19. 菲律宾褐铁矿型红土镍矿还原焙砂氨浸试验研究%Ammonia Leaching of Reduction Calcine of Philippines Limonitic Laterite Ore

    Institute of Scientific and Technical Information of China (English)

    李小波; 轩辂; 杨琦

    2014-01-01

    研究了用还原焙烧-氨浸工艺(RRA L )从菲律宾某褐铁矿型红土镍矿中提取镍、钴和铁,确定了最佳工艺条件。结果表明:在焙砂细度为-74μm占96.34%、N H3和CO2质量浓度比为90 g/L∶60 g/L、矿浆质量浓度为100 g/L、浸出时间为150 min、充气量为1.2~1.5 mL/(min · g焙砂)条件下,镍、钴浸出率分别为88.02%和50.16%,浸出渣中全铁质量分数为59.75%。%The reduction roasting-ammonia leaching (RRAL ) process is used to extract nickel and cobalt ,and recover Fe from Philippines limonitic laterite ore .The optimum conditions are confirmed . T he results show that under the conditions of calcine fineness of -74 μm acountiong for 96 .34% , N H3 and CO2 mass concentration ratio of 90 g/L∶60 g/L ,slurry concentration of 100 g/L ,ammonia leaching time of 150 minutes ,aeration volume between 1 .2 -1 .5 mL/(min · g calcine) ,the leaching rate of nickel and cobalt reach 88 .02% and 50 .16% ,respectively ,and Fe mass fraction in leaching residue is 59 .75% .

  20. Research on Treatment of Ammonia in Wastewater With Calcined-aluminum Pillared Bentonite%煅烧铝柱撑膨润土处理氨氮废水的试验研究

    Institute of Scientific and Technical Information of China (English)

    孙玉焕; 赵娇娇; 马翔

    2013-01-01

    With the hydrolysis and polymerization nature of aluminum ion, aluminum pillared bentonite which n(OH-) : n(A13+) =2.0 was prepared by hydro-thermal ino-exchage methods with Sodium bentonite as raw material and was calcined at 500℃ for 2h. The effects of calcined aluminum pillared bentonite dosage, waste water pH, reaction time, temperature and the original ammonia concentration on the ammonia were studied. The results showed that the ammonia removal efficiency reached the maximum under following conditions: the ammonia initial concentration wasl00mg/L, the dosage quatity was 3.0g/25mL, pH value was 9, the temperature was 25℃, the adsoprtion time was 60min, and the removal ratio reached 86.9%.%利用铝离子水解聚合的性质,以钠基膨润土为原料,采用水热法制备了n(OH-)∶n(Al3+)=2.0羟基铝柱撑膨润土,将其在500℃下煅烧2h.研究了经煅烧后柱撑膨润土投加量、溶液pH值、时间、温度、初始氨氮浓度对氨氮吸附性能的影响.结果表明:当氨氮初始浓度为100mg/L,投加量为3.0g/25mL、pH值为9、温度为25℃、时间为60min时,氨氮的去除率达到最大,可达到86.9%以上.

  1. Study on the Process of the Preparation of Activated MgO by Calcining Magnesite%菱镁矿煅烧制备高活性MgO工艺

    Institute of Scientific and Technical Information of China (English)

    徐鹏; 朱静; 高小明; 康征; 杨家宽

    2013-01-01

    主要对高活性MgO及镁基水泥的制备工艺进行研究.利用小库容回转炉煅烧菱镁矿制备轻烧MgO,通过柠檬酸显色法和修正水化法测定菱镁矿在不同条件下煅烧产物的活性,分析煅烧过程中煅烧温度、保温时间、升温速率等因素对煅烧产物活性的影响.再以煅烧产物轻烧MgO作为基本原料之一配制镁基水泥并制备水泥试块,探究镁基水泥的强度特性以及不同养护方式对其产生的影响.结果表明镁基水泥在标准养护条件下强度较低,但碳化养护可以很大程度提高镁基水泥的强度,达到普通硅酸盐水泥的强度水平.同时根据水泥试块在碳化养护过程中的增重情况,分析使用含高活性MgO的镁基水泥作为CO2捕集与封存材料的可行性.%The research on the preparation of activated MgO and Mg-based cement was carried on in this paper. The magnesite of the little storage capacity rotary furnace was adopted to prepare light-burnt MgO. The activation of calcinate under different condition was determined by the citric acid coloration method and the correction hydration method and the influence of calcination temperature, holding time and heating rate on the activation of calcinate was analyzed. Then the light-burnt MgO was used as one of the basic raw materials to prepare Mg-based cement and cement block. Meanwhile,the influence of strength properties of Mg-based cement and different curing methods were studied. The results showed that the strength of the Mg-based cement was relatively low in the standard curing condition, but the carbonated curing can greatly improve the level of Mg-based cement strength, reaching the level of the ordinary portland cement. At the same time, according the weight gain of the cement block during the course of carbonated curing,the feasibility of using high activity of MgO as CO2 capture and sealing materials was analyzed.

  2. XRD analysis of the composition of impurities in the magnesia produced by calcining magnesite%XRD分析菱镁石矿煅烧制备的镁砂中杂质组成

    Institute of Scientific and Technical Information of China (English)

    蒋晓光; 林忠; 李卫刚; 潘德喜; 储刚

    2011-01-01

    Using the X-ray diffraction(XRD)technology,analysed the compositiog of the magnetite ore and the magnesite clinker. The result showed that the mass fraction of original MgCO3 in the magnetite ore has reached 96%(wt) and the impurities are mainly CaCO3 and Si()2. MgCO3 in light-burned magnesia has been largely decomposed to MgO with 32%(wt)of MgCO3 left to form new trace phase of CaMg(CO3)2 and Mg(()H)2 in the low-temperature calcination. MgCO3 in dead-burned magnesia has been completely decomposed into MgO coupling with the release of carbonyl which may exist in light-burned magnesia and the impurities are mainly Mg2Si04 and CaOCabout 7%(wt)of the total). The result will be the reference for reforming purification process to improve the quality of magnesia by calcining magnesite.%采用X射线衍射技术(XRD)对菱镁原矿和镁砂产品进行了物相组成分析,菱镁石原矿粉中主相ω( MgCO3)达到96%,杂质主要是CaCO3和SiO2;轻烧镁砂中的MgCO3大部分已经分解为MgO,但还有质量分数32%的MgCO3未分解,并在低温煅烧的情况下生成了微量的新相CaMg(CO3)2和Mg(OH)2;重烧镁砂中的MgCO已经完全分解为MgO,而且轻烧产物中存在的羰基相的羰基也已经完全脱出,杂质主要存在形式是Mg2SiO4和CaO,约占总质量的7%.其结果将成为提高菱镁矿煅烧生产的镁砂品质而改进提纯工艺的参考依据.

  3. Preparation and Application of the Sol-Gel Combustion Synthesis-Made CaO/CaZrO3 Sorbent for Cyclic CO2 Capture Through the Severe Calcination Condition

    Institute of Scientific and Technical Information of China (English)

    Baowen Wang; Xiaoyong Song; Zonghua Wang; Chuguang Zheng

    2014-01-01

    abstract Calcium looping method has been considered as one of the efficient options to capture CO2 in the combustion flue gas. CaO-based sorbent is the basis for application of calcium looping and should be subjected to the severe calcination condition so as to obtain the concentrated CO2 stream. In this research, CaO/CaZrO3 sorbents were synthesized using the sol-gel combustion synthesis (SGCS) method with urea as fuel. The cyclic reaction performance of the synthesized sorbents was evaluated on a lab-scaled reactor system through calcination at 950 °C in a pure CO2 atmosphere and carbonation at 650 °C in the 15%(by volume) CO2. The mass ratio of CaO to CaZrO3 as 8:2 (designated as Ca8Zr2) was screened as the best option among al the synthesized CaO sorbents for its high CO2 capture capacity and carbonation conversion at the initial cycle. And then a gradual decay in the CO2 capture capacity was observed at the following 10 successive cycles, but hereafter stabilized throughout the later cycles. Furthermore, structural evolution of the carbonated Ca8Zr2 over the looping cycles was investigated. With increasing looping cycles, the pore peak and mean grain size of the carbonated Ca8Zr2 sorbent shifted to the bigger direction but both the surface area (SA) ratioΦand surface fractal dimension Ds decreased. Finally, morphological transformation of the carbonated Ca8Zr2 was observed. Agglomeration and edge rounding of the newly formed CaCO3 grains were found as aggravated at the cyclic carbonation stage. As a result, carbonation of Ca8Zr2 with CO2 was observed only confined to the external active CaO by the fast formation of the CaCO3 shell outside, which occluded the further carbonation of the unreacted CaO inside. Therefore, enough attention should be paid to the carbonation stage and more effective activation measures should be explored to ensure the unreacted active CaO fully carbonated over the extended looping cycles.

  4. Adsorption of glutamic acid from aqueous solution with calcined layered double Mg-Fe-CO3 hydroxide%Mg-Fe-CLDH对模拟谷氨酸废水的吸附分离

    Institute of Scientific and Technical Information of China (English)

    焦飞鹏; 帅丽; 于金刚; 蒋新宇; 陈晓青; 杜邵龙

    2014-01-01

    Layered double Mg−Fe−CO3 hydroxide (Mg−Fe−LDH) with a mole ratio of Mg to Fe of 3 was synthesized by coprecipitation method and calcined product Mg−Fe−CLDH was obtained by heating Mg−Fe−LDH at 500 °C for 6 h. The as prepared Mg−Fe−LDH and calcined Mg−Fe−CLDH were used for removal of glutamic acid (Glu) from aqueous solution, respectively. Batch studies were carried out to address various experimental parameters such as contact time, pH, initial glutamic acid (Glu) concentration, co-existing anions and temperature. Glu was removed effectively (99.9%) under the optimized experimental conditions with Mg−Fe−CLDH. The adsorption kinetics follows the Ho’s pseudo second-order model. Isotherms for adsorption with Mg−Fe−CLDH at different solution temperatures were well described using the Langmuir model with a good correlation coefficient. The intraparticle diffusion model fitted the data well, which suggests that the intraparticle diffusion is not only the rate-limiting step.%采用共沉淀法合成Mg与Fe摩尔比为3:1的层状双金属氢氧化物(Mg−Fe−LDH),然后在500°C下煅烧6 h得到煅烧双金属氢氧化物(Mg−Fe−CLDH)。分析Mg−Fe−CLDH与Mg−Fe−LDH对谷氨酸的吸附性能,研究溶液 pH、谷氨酸初始浓度、共存阴离子及温度等因素对吸附效果的影响,并对其吸附过程的动力学和热力学过程进行研究。结果表明:Mg−Fe−CLDH对谷氨酸的吸附效果很好,吸附率在优化条件下达到99.9%;吸附动力学符合准一级动力学方程,平衡吸附等温线很好地符合 Langmuir 方程。颗粒内扩散模型能很好地描述吸附动力学过程。颗粒内扩散模型拟合结果显示,颗粒内扩散不是唯一的反应速率控制步骤。

  5. 煅烧硅藻土对再生混凝土抗压强度影响研究%Experimental study on the influence of calcined diatomite on compressive strength of recycled concrete

    Institute of Scientific and Technical Information of China (English)

    岳志鑫; 李佰寿

    2015-01-01

    对三组不同掺量的煅烧硅藻土再生细石混凝土与普通细石混凝土做了对比试验,指出三组再生混凝土7d强度随着硅藻土掺量的增加而降低;28 d强度均低于普通混凝土;硅藻土掺量3%的混凝土强度略高,建议煅烧硅藻土掺量控制在3%以内。%Three groups of recycled fine aggregate concrete and normal fine concrete were done contrast test. Recycled concrete 7 d strength grad-ually reduce with the increase of diatomite proportion,research shows that:the three groups of recycled concrete 28 d strength were lower than that of normal concrete,higher for the concrete with 3% proportion. Suggest calcined diatomite proportion control within 3%.

  6. 焙烧条件对Fe - Mo/ZSM-5催化剂上NO选择性催化还原性能的影响%Effects of calcination conditions on catalytic performance of Fe-Mo/ZSM-5 catalyst for SCR reaction of NO

    Institute of Scientific and Technical Information of China (English)

    王晓丽; 娄晓荣; 黄伟; 李哲

    2011-01-01

    Fe-Mo/ZSM-5 catalyst with to ( Fe): m ( Mo) =1 was prepared by co-impregnation method under different calcination conditions. Their catalytic performance for selective catalytic reduction (SCR) for nitrogen oxides was investigated. The results showed that the calcination conditions had evident influence on the performance of Fe-Mo/ZSM-5 catalyst. The catalyst calcinated at 600 ℃ for 6 h exhibited better performance for SCR of nitrogen oxides;the curve of Nox conversion was shifted to higher temperature with the increase of calcination time and calcination temperature. The catalytic activity of the catalyst calcined at 800 ℃ was dropped obviously. The bulk phase and surface properties of Fe-Mo/ZSM-5 catalyst were also characterized by XRD and BET techniques. The results indicated that the lattice constants and the surface area of Fe-Mo/ZSM-5 catalysts were changed under different calcination conditions. When cal-canation temperature was 800 ℃, the surface area was reduced obviously, which could be the main cause of activity reduction of the catalyst. The residual nitrous species on the catalyst surface after calcination had important influence on the activity of Fe-Mo/ZSM-5 catalyst for the selective catalytic reduction of nitrogen oxides.%采用共浸渍法制备了m(Fe):m(Mo)=1的Fe - Mo/ZSM -5催化剂,并对其在不同焙烧条件所得样品上NO选择性催化还原反应活性进行了测试.结果表明,焙烧条件对Fe - Mo/ZSM -5催化性能影响明显,600℃焙烧6h的样品在低温范围具有较好的催化性能,随着焙烧时间或焙烧温度的增加,其NOx转化率依次向高温方向移动,在800℃焙烧后的样品催化活性明显下降.采用XRD和BET对Fe - Mo/ZSM -5样品的体相结构和表面性能进行了研究.结果表明,不同焙烧条件下Fe - Mo/ZSM -5催化剂的晶胞参数和比表面积产生了差别,特别是焙烧温度达到800℃时,其比表面积显著减小,这可能是导致Fe - Mo/ZSM -5催化性能突

  7. Effect of calcination temperature on microstructure and magnetic properties of Ni{sub 0.5}Zn{sub 0.25}Cu{sub 0.25} Fe{sub 2}O{sub 4} nanoparticles synthesized by sol-gel method

    Energy Technology Data Exchange (ETDEWEB)

    Pransisco, Prengki, E-mail: prengkipransisco@gmail.com, E-mail: afza@petronas.com.my; Shafie, Afza, E-mail: prengkipransisco@gmail.com, E-mail: afza@petronas.com.my [Department of Fundamental and Applied Sciences, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia); Guan, Beh Hoe, E-mail: beh.hoeguan@petronas.com.my

    2014-10-24

    This paper examines the effect of calcination process on the structural and magnetic properties material nanostructure composite of Ni{sub 0Ð}œ‡{sub 5}Zn{sub 0Ð}œ‡{sub 25}Cu{sub 0.25} Fe{sub 2}O{sub 4} ferrites. The samples were successfully prepared by sol-gel method at different calcination temperature, which are 600°C, 700°C, 800°C and 900°C. Morphological investigation, average crystallite size and microstructure of the material were examined by using X-ray diffraction (XRD) and confirmed by high resolution transmission electron microscope (HRTEM) and field emission scanning electron microscope (FESEM). The effects of calcination temperature on the magnetic properties were calculated by using vibrating sample magnetometer (VSM). The XRD result shows single-phase cubic spinel structure with interval average size 5.9-38 nm, and grain size microstructure of the material was increasing with temperature increases. The highest magnetization saturation was reached at a temperature 800°C with value 53.89 emu/g, and the value coercive force (Hc) was inversely with the grain size.

  8. Effect of calcination temperature on structure and methanation performance of supported Mo catalyst%焙烧温度对负载型 Mo 基催化剂结构与甲烷化性能的影响

    Institute of Scientific and Technical Information of China (English)

    秦绍东; 龙俊英; 田大勇; 汪国高; 孙守理; 孙琦

    2014-01-01

    CeO2-Al2O3 supports prepared by impregnation were calcinated at 500℃ or 700℃, then loaded with Co and Mo by impregnation, and the obtained Co-Mo/(CeO2-Al2O3) catalyst precursors were subjected to a second heat treatment at 500℃ or 700℃. The catalysts were characterized by N2 adsorption, H2-TPR, XRD and SEM, and their methanation performances were tested at 550℃, 3MPa, 5000h-1, and n (H2)/n (CO)=1.0 in the syngas containing H2S. The results indicated that the surface area of the catalyst was mainly affected by the calcination temperature of CeO2-Al2O3 support. While the dispersion of Co and Mo species were largely determined by the heat treatment temperature of catalyst precursor. The catalyst with the CeO2-Al2O3 support caicinated at 500℃ and the catalyst precursor treated at 700℃ showed the highest Co and Mo dispersion and the highest activity in methanation reaction.%以浸渍法制备得到的 CeO2-Al2O3复合氧化物载体于500℃或700℃焙烧处理,浸渍 Co 和 Mo 物种后得到 Co-Mo/(CeO2-Al2O3)催化剂前驱体,再于500℃或700℃进行焙烧处理得到催化剂。采用 N2物理吸附、H2程序升温还原、X 射线衍射及扫描电子显微镜对催化剂进行了表征,在固定床上于550℃,3MPa,5000h-1,n(H2)/n(CO )为1.0且含有 H2S 的合成气中对催化剂的甲烷化性能进行了测试。结果表明 CeO2-Al2O3载体的焙烧温度对催化剂比表面积有较大影响,而催化剂表面 Co 与 Mo 物种的分散度主要受催化剂前驱体焙烧温度的影响。当 CeO2-Al2O3载体于500℃焙烧催化剂前驱体于700℃焙烧后,Co 与 Mo 物种的分散度最好,催化剂甲烷化活性最高。

  9. 流态化下电石渣循环煅烧/碳酸化捕集CO2特性%CO2 Capture Characteristics of Carbide Slag in Cyclic Calcination/Carbonation Under Fluidization State

    Institute of Scientific and Technical Information of China (English)

    李英杰; 谢辛; 孙荣岳; 时雷

    2014-01-01

    在鼓泡流化床上研究电石渣在循环煅烧/碳酸化反应中的 CO2捕集特性,考察循环次数、反应温度、流化数和颗粒粒径对流态化下电石渣循环碳酸化转化率和速率的影响。结果表明:循环次数增加使电石渣碳酸化转化率衰减,经过50次循环其转化率可达0.2,高于石灰石。反应初期,电石渣碳酸化速率低于石灰石,但经过一段时间后高于石灰石。碳酸化温度为700℃,煅烧温度为850~900℃时可使电石渣保持较高循环捕集 CO2性能。增加流化数提高了电石渣化学反应控制阶段的碳酸化速率,对产物层扩散阶段速率影响较小。颗粒粒径增大对化学反应控制阶段速率影响不大,但降低了产物层扩散阶段速率。%The CO2 capture behavior of carbide slag in cyclic calcination/carbonation reactions was investigated in a bubbling fluidized bed reactor. The effects of cycle number, reaction temperature, fluidization number and particle size on cyclic carbonation conversions and rates of carbide slag were examined. The results show that the carbonation conversion of carbide slag decreases with the number of cycles and achieves about 0.2 after 50 cycles, which is higher than that of limestone. In the initial reaction stage, the carbonation rate of carbide slag is lower than that of limestone, but after a time the former is higher than the latter. Carbide slag maintains higher CO2 capture capacity for carbonation at 700℃ and for calcination at 850~900℃. The carbonation rate of carbide slag in the chemical reaction-controlled stage increases with increasing fluidization number, while that in the product layer diffusion-controlled stage does not change apparently. The increase of particle size does not affect the carbonation rate of carbide slag in the chemical reaction-controlled stage, but it decreases the carbonation rate in the product layer diffusion- controlled stage.

  10. Effects of La3+–Nd3+ ions and pre-calcination on the growth of hexaferrite nanoparticles prepared by gel to crystallization technique: Non-isothermal crystallization kinetics analysis

    International Nuclear Information System (INIS)

    This is the first report ever on La3+–Nd3+ doped M-type hexaferrite nanoparticles: SrNdxLayFe12−x−yO19 (0 ≤ x ≤ 1) prepared by citrate precursor using the sol–gel technique followed by gel to crystallization. The substitution effects of ions and molar ratio of Fe3+/Sr2+ on the formation of ferrite phase were examined using powder differential thermal analysis (DTA) technique, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (Mid-IR) and vibrating sample magnetometer (VSM). The present work aim to study the crystallization of binary La3+- Nd3+ doped hexaferrite nanoparticles. DTA technique was employed to investigate the formation of nanocrystalline SrNd0.4La0.4Fe11.2O19 and revealed that the formation of ferrite phase was occurred in steps and crystallization take place by the means of endothermic reactions. The value of activation energy and crystallization temperature has been obtained from DTA data using different non-isothermal methods. XRD and Mid-IR studies have confirmed the formation of ferrite phase. Through this work an optimum calcination condition was established for the synthesis of single phase hexaferrite nanoparticles even after the substitution of binary rare earth elements. Magnetic properties were determined by using a vibrating sample magnetometer. The magnetic results revealed that the synthesized nanoparticles are suitable for perpendicular recording media due to their high coercivity value. - Highlights: • First report of studies on Nd3+–La3+ doped M-type strontium hexaferrite nanoparticles. • Studied the crystallization of binary (Nd3+–La3+) doped hexaferrite nanoparticles. • Studied the effects of La3+–Nd3+ & molar ratio of Fe3+/Sr2+ on the formation of ferrite phase. • Established an optimum condition to obtain single phase hexaferrite nanoparticles. • Magnetic measurements show a significant improvement in coercivity value

  11. 酸浸和焙烧对硅藻土吸附甲醛性能的影响研究%The Influence of Acid-treating and Calcination on Adsorption Properties to Formaldehyde of Diatomite

    Institute of Scientific and Technical Information of China (English)

    王佼; 郑水林

    2011-01-01

    采用酸浸和焙烧法对硅藻土进行了提纯处理,通过SEM和XPS及比表面积测定仪等测试手段对提纯前后的硅藻土进行了表征;并研究了硅藻土对甲醛的吸附性能.结果表明,提纯后的硅藻土SiO2含量显著提高,Fe2O3含量显著下降,比表面积显著增大,对甲醛的吸附性能明显提高.在常温下,影响其吸附的两个因素(甲醛初始量及环境湿度)的最佳范围分别为:甲醛最佳初始浓度为5 μL/m3;最佳环境舱湿度范围为30%RH至40%RH;硅藻土的最佳吸附效率为37.92%.%After diatomite was calcined and treated with sulfuric acid to remove impurity, the purified diatomite was compared with the crude diatomite by SEM, XPS and BET and the adsorption properties to formaldehyde of diatomite. The results showed that the amount of SiO2 increased sharply; meanwhile, the amount of Fe2O3 dropped notably and the specific surface area was enlarged. Therefore, the adsorption capacity was improved. At room temperature, two critical factors, the initial amount of formaldehyde and ambient humidity, have their optimum range. The former should be 5 mL/m3 and the latter should range from 30 % RH to 40 % RH. Then the best adsorption value of diatomite is 37.92 %.

  12. The Effect of Calcination on the Properties of Nano-TiO2/Silica Residue of Demagging Asbestos Tailings Composite%煅烧对纳米TiO2/石棉尾矿脱镁硅渣复合材料性能的影响

    Institute of Scientific and Technical Information of China (English)

    孙青; 郑黎明; 郑水林; 李慧; 戴瑞

    2014-01-01

    以石棉尾矿脱镁硅渣为载体,采用TiCl4水解法制备了纳米TiO2/石棉尾矿脱镁硅渣复合粉体,通过煅烧使载体表面负载的纳米TiO2晶态化;研究了煅烧温度、煅烧时间对复合材料光催化性能的影响,并用XRD分析技术对复合材料进行了表征。结果表明,复合材料光催化活性最优的煅烧温度、煅烧时间分别为800℃、2 h,此条件下复合材料对罗丹明B光催化降解率为90.5%;纳米TiO2以锐钛矿晶型负载于石棉尾矿脱镁硅渣上,平均晶粒尺寸为20.9 nm。%Using the silica residue of demagging asbestos tailings as the carrier, the nano-TiO2/silica residue of demagging asbestos tailings composite power was prepared by the hydrolysis of TiCl4. Then the nano-TiO2 loaded on the surface of carrier was crystallized through calcination. The effects of calcination temperature, calcination time on the photocatalytic activity of the composite were investigated. And the structure of the composite was characterized by XRD. The results indicate that the calcination temperature and calcination time for a optimal photocatalytic activity of the composite is 800℃ and 2h, respectively. Under this condition, the degradation rate of Rhodamine B is 90.5% on the composite. The nano-TiO2 is immobilized on the silica residue of demagging asbestos tailings in the crystal of anatase. And the average grain size of nano-TiO2 is 20.9nm.

  13. Treatment of Trace Perchlorate from Water by Calcined MgAl-CO_3 Layered Double Hydroxides%焙烧态MgAl-CO_3双羟基层状金属化合物去除水中痕量高氯酸盐

    Institute of Scientific and Technical Information of China (English)

    杨一琼; 高乃云; 郭洪光; 马艳

    2012-01-01

    MgAl-CO3 hydrotalcites with different Mg/Al mole ratios were prepared by co-precipitation method,and calcined to get the calcined samples.The adsorption capacity of trace perchlorate ion from water on calcined samples was measured,the influence of initial perchlorate concentration,varying pH of solution,temperature,particle size,and co-existed anions concentration on the adsorption capacity of calcined samples were studied,kinetic parameters were obtained.Results showed that the best synthesis conditions to maximize the perchlorate adsorption capacity of the calcined MgAl-CO3 layered double hydroxides are the calcination temperature of 550 ℃ and n(Mg2+)/n(Al3+),which fit well with second-order kinetic equation and Freundlich isotherm model.It could be used as a buffer.in a wide range of pH But in strong acid conditions,the calcined hydrotalcite may be dissolved,while in strong alkali condition,the perchlorate removal was lower as a consequence of the competition between OH-and ClO4-.%用共沉淀法制备了不同配比的MgAl-CO3双羟基层状金属化合物,焙烧后制得焙烧态水滑石。考察了MgAl-CO3双羟基层状金属化合物及其焙烧产物对水中痕量高氯酸根离子的吸附性能,研究了初始浓度、pH值、温度、粒径、共存阴离子等对去除效能的影响,计算得到了有关动力学参数。结果表明:550℃焙烧态水滑石(n(Mg2+)/n(Al3+)=3)对ClO4-的吸附效果最好,且符合准二级反应动力学方程和Freundlich等温吸附模型。焙烧态水滑石对溶液的pH值具有一定的缓冲作用,在较宽的pH范围均可广泛应用。但是在强酸条件下水滑石会发生溶解;强碱条件下OH-会与ClO4-形成吸附竞争。

  14. Effects of calcination temperature on the structure and electrical property of Ca1-xPrxMnO3 powders%煅烧温度对Ca1-xPrxMnO3粉体结构与导电性能的影响

    Institute of Scientific and Technical Information of China (English)

    付秋月; 郝素娥; 孟宪伟; 李佳龙; 李云娇

    2012-01-01

    To improve the electrical properties of CaMnO3 powders,the modified Ca1-xPrxMnO3(0≤x≤0.3) powders were prepared by the sol-gel auto-combustion route at different calcination temperatures and the effects of calcination temperature on the structure and electrical conductivity of the powders were characterized.It was indicated that the resistivity of modified powders represented the typical V type variation of firstly decreased and then increased with the increasing of calcination temperatures,and the resistivity was the lowest when the calcination temperature was at 1 000 ℃.The XRD analysis illustrated that with the increasing of calcination temperatures,the diffraction peaks of Ca1-xPrxMnO3 powders were moved to the small angles with the strengthening in intensity.The crystallography data calculated from XRD illustrated that the cell parameters which related to the resistivity of Ca1-xPrxMnO3 powders were affected by the calcination temperatures.When the calcination temperature was at 1 000 ℃,the crystal distortion was most distinct.The SEM analysis illustrated that the higher calcination temperature led to the larger size of grains,and the suitable grain size was good at decreasing the resistivity of Ca1-xPrxMnO3 powders.Moreover,the quantivalency of Mn was the lowest when the Ca1-xPrxMnO3 powders were calcined at 1 000 ℃.The grain boundary,grain size and the quantivalency of Mn together lead to the decreasing then increasing type variation of the resistivity of Ca1-xPrxMnO3 powders calcined at different temperatures.%为改善CaMnO3粉体的导电性能,采用溶胶-凝胶自蔓延法在不同温度下合成Ca1-xPrxMnO3(0≤x≤0.3)粉体,并研究煅烧温度对Ca1-xPrxMnO3粉体结构及导电性能的影响.结果表明,随着煅烧温度的升高,电阻率呈现先降低后升高的变化趋势,且在1 000℃时电阻率最低.XRD分析结果表明,Ca1-xPrxMnO3粉体的特征衍射峰均向小角度方向偏移,且强度随着煅烧温度的升

  15. Calcining Serpentine with Ammonium Sulfate for Preparation of Ultrafine Magnesium Hydroxide%用蛇纹石硫酸铵焙烧法制备超细氢氧化镁的研究

    Institute of Scientific and Technical Information of China (English)

    宋贝; 刘超; 郑水林; 戴瑞; 侯会丽

    2013-01-01

    Calcining serpentine with ammonium sulfate to extract magnesium for preparaion of ultrafine magnesium hydroxide. This paper studies the effect of temperature on the performance of the preparation of ultrafine magnesium hydroxide, which come to the conclusion the appropriate reaction temperature is 40℃. The results show that superfine magnesium hydroxide particles occur agglomeration and have large specific surface area. In order to overcome the agglomeration of the magnesium hydroxide and decrease the surface area, the magnesium hydroxide hydrothermal reaction is carried on and the appropriate condition of hydrothermal time is 3 h. Through analysis of their chemical composition, particle size distribution, surface area and SEM, it shows that after the hydrothermal reaction magnesium hydroxide specific surface area is 13.79 m2/g, the content of MgO is 68.23%, and has good crystalline form.%  以蛇纹石为原料,通过硫酸铵焙烧法提取蛇纹石中的镁,并制备超细氢氧化镁。研究了温度对制备超细氢氧化镁性能的影响,得出适宜反应温度为40℃,SEM测试结果表明,制备的超细氢氧化镁颗粒间发生了较多团聚,比表面积较大。为克服氢氧化镁的团聚现象,降低比表面积,将氢氧化镁在反应釜中进行水热反应,得出适宜水热时间为3 h。化学分析以及粒度、比表面积、SEM测试结果表明,水热反应后氢氧化镁比表面积为13.79 m2/g,MgO含量为68.23%,晶型较好。

  16. Modelación del proceso de calcinación flash durante la activación de arcillas // Modeling of the flash calcination process during clay activation

    Directory of Open Access Journals (Sweden)

    Rubén Borrajo‐Pérez

    2012-01-01

    temperatureof particles are obtained as a function of the gas parameters. The calculation includes the heat losses andthe model predicts the residence time of a particle in an activation unit.Key words: puzzolan, flash, calcinations, modeling.

  17. 水蒸气对煅烧石灰石碳酸化反应影响的实验与模型分析%Experimental and model study of carbonation of calcined limestone in presence of steam

    Institute of Scientific and Technical Information of China (English)

    刘洋; 杨勇平

    2015-01-01

    Steam is present in combustion flue gas, oxy-fuel combustor/calciner and fuel gas. Some previous works in this field have examined the reactivity of calcium oxide in the presence of steam. There is general agreement that the presence of steam increases the rate of carbonation even at low concentrations. However, there is no description about the effect of steam on the carbonation reaction of calcined limestone. The effects of temperature, concentration of steam on carbonation were investigated in a thermogravimetric analyzer. The understanding of the mechanisms participating in the carbonation reaction could be arrived at through the use of model interpretations of the rate controlling process. The experimental data were analyzed by means of the random pore model. During carbonation reaction, a very initial rapid reaction was followed by the second stage of the reaction occurring in the next slower regime. The experiment results showed that the effect of steam on carbonation could be neglected during the first stage of reaction. However, the conversion of carbonation in the presence of 1.5%(vol), 10%(vol) and 20%(vol) steam were 19.8%, 27.2%and 30.5%higher than the conversion without steam after 10 min during the second stage of reaction at 500℃. Steam was beneficial to enhancing the conversion of carbonation, but the extent of increase became not significant with increasing concentration of steam. The linearity of the second stage reaction data strongly suggested that this stage was controlled by a diffusion process occurring in a layer of calcium carbonate surrounding the calcium oxide in the pores of the solid. The parameters related to effective product layer diffusivities were plotted in Arrhenius form and the changes in activation energy at various steam concentrations were also shown. Comparison with the experimental effective diffusivities calculated for the carbonation reaction showed that the activation energies in the lower temperature range were in

  18. Desempenho mecânico de misturas asfálticas confeccionadas com agregados sintéticos de argila calcinada Mechanical performance of asphalt mixtures composed of synthetic calcinated clay aggregates

    Directory of Open Access Journals (Sweden)

    C. A. Frota

    2007-09-01

    .A substantial number of municipal districts in the State of Amazonas are located in areas which are poor in stony materials. And this has led pavement builders into adopting alternatives which have historically produced pavements with low mechanical strength. Whist more effective and appropriate from a technical standpoint, the asphalt concrete has been usually left aside due to the referred lack of stony materials. Because of the specific situation in the State of Amazonas the adoption of synthetic calcinated clay aggregates (SCCA, with an abundant raw material (clay in the State of Amazonas is recommended in lieu of the traditional practice. Previous works carried out by the Federal University of Amazonas Geotechny Group have demonstrated that the clay soil commonly used in the production of ceramic materials can yield synthetic aggregates with adequate mechanical properties. In this research work, samples featuring similar characteristics as those of the soils in question have been found along the BR-319 highway connecting the Manaus (AM city to Porto Velho (RO city. The transportation structure in general is in deplorable conditions. Justifiably so, the recovery of this highway has been earmarked as one of the targets for the Ministry of Transportation. In this study, asphalt mixtures were blended with synthetic aggregates and pebbles taken from the river bed in order to compare the mechanical performance of such mixtures by means of the determination of the resilient modulus (RM. The results, as a rule, have shown that the asphalt mixtures comprising synthetic calcinated clay aggregates when compared with those comprising the naturally-found material (river bed pebbles have shown: (a greater tensile and resilient modulus strengths; (b low deformation tendency, as well as a considerable elastic recovery and (c less susceptibility to permanent deformation.

  19. Microstructure and magnetic properties of M-type Sr{sub 0.61−x}La{sub 0.39}Ca{sub x}Fe{sub 11.7}Co{sub 0.3}O{sub 19} hexaferrite prepared by microwave calcination

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Zhongyan, E-mail: chenzhongyan88@163.com; Wang, Fan; Yan, Shuoqing; Feng, Zekun

    2014-03-15

    Highlights: • We successfully prepared M-type Sr{sub 0.61−z}La{sub 0.39}Ca{sub z}Fe{sub 11.7}Co{sub 0.3}O{sub 19} ferrites samples using microwave calcining technique, which is an effective method for preparing the hexaferrites and controling the grain size. • The magnetic properties of the samples with the composition of Sr{sub 0.61−z}La{sub 0.39}Ca{sub z}Fe{sub 11.7}Co{sub 0.3}O{sub 19} were markedly improved when x ≤ 0.2. With the composition of Sr0.41La0.39Ca0.2Fe11.7Co0.3O19 calcined at 1140 °C for 30 min using microwave calcining, the largest saturation magnetization of 68.3 emu/g and coercivity of 5320 Oe were observed for the sample. -- Abstract: M-type Sr{sub 0.61−x}La{sub 0.39}Ca{sub x}Fe{sub 11.7}Co{sub 0.3}O{sub 19} ferrites with various calcium concentrations (x = 0, 0.1, 0.2, 0.3) were prepared through microwave calcining. The microstructure, morphology and magnetic properties of the samples were evaluated by X-ray diffraction, scanning electron microstructure and vibrating sample magnetometry, respectively. Results showed that more Fe{sup 3+} ions were substituted by Co{sup 2+} with the increase of calcium substitution, which suppressed the formation of the impurity phases to improve the magnetic properties. The coercivity and saturation magnetization of the samples with the composition of Sr{sub 0.61−x}La{sub 0.39}Ca{sub x}Fe{sub 11.7}Co{sub 0.3}O{sub 19} can be remarkably improved when x = 0.2.

  20. 焙烧温度对甲硫醇催化剂K2WO4/Al2O3结构和性能的影响%Effect of Calcination Temperature on the Structure and Catalytic Performance of K2WO4/Al2O3 Catalysts for Methanethiol Synthesis

    Institute of Scientific and Technical Information of China (English)

    张元华; 陈世萍; 袁成龙; 方维平; 杨意泉

    2012-01-01

    研究了焙烧温度对溶胶-凝胶法制备的甲硫醇催化剂K2WO4/Al2O3的表面结构和催化性能的影响.表征结果显示,K2WO4在Al2O3上分散得较好,在450和550℃焙烧的催化剂颗粒大小均匀,无明显团聚现象.随着焙烧温度的升高,催化剂的比表面积减小,表面钨物种与Al2O3的相互作用减弱,与碱物种的相互作用增强,酸碱强度降低.K2WO4/Al2O3表面不含质子酸.催化剂活性与其比表面积及表面的共轭酸碱对密切相关.评价结果表明,在550℃焙烧而制得的催化剂活性最高.%The effect of calcination temperature on the surface morphology and catalytic performance of the K2WO4/Al2O3 catalyst prepared by the sol-gel method for the synthesis of methanethiol from methanol and hydrogen sulfide was investigated. Physicochemical characterization results of the catalyst showed that the K2WO4 is well dispersed on Al2O3, and the catalyst possesses uniform particle size after calcination at 450 or 550 °C. With increasing the calcination temperature, the specific surface area decreases, the interaction of W species with Al2O3 was weakened, but strengthened with basic species, leading to the decrease of surface acidity and basicity. No Br(o)nsted acid was found on the catalyst surface. The catalytic activity of the catalyst is closely related with the specific surface area and the presence of conjugate acid-base pairs on the surface. Activity assay results show that the catalyst calcined at 550 °C exhibits the highest activity for the reaction.

  1. Potencialidades de um caulim calcinado como material de substituição parcial do cimento portland em argamassas Potentialities of a calcined kaolin as material of partial replacement of portland cement in mortars

    Directory of Open Access Journals (Sweden)

    Marilia P. de Oliveira

    2006-06-01

    Full Text Available A utilização de argilas calcinadas na forma de metacaulinita, como material pozolânico para argamassas e concretos, tem recebido atenção considerável nos últimos anos. Este trabalho objetivou avaliar o desempenho mecânico de argamassas, nas quais foi utilizado um caulim calcinado proveniente do Estado da Paraíba, como material de substituição parcial do cimento Portland. Utilizaram-se duas finuras do caulim: passando nas peneiras ABNT 200 (0,074 mm e 325 (0,044 mm e calcinados nas temperaturas de 700, 800 e 900 ºC pelo tempo de 2 h. As amostras foram caracterizadas através de análise química, análise térmica diferencial, difração de raios-X e área específica. Obteve-se o índice de atividade pozolânica com a cal e o cimento Portland. O percentual de substituição adotado foi de 0, 10, 20, 30 e 40%. A relação aglomerante: areia foi de 1:1,5 e a relação água/aglomerante fixada igual 0,4. O efeito da substituição parcial do cimento na argamassa foi avaliado através da resistência à compressão simples, nas idades de 7, 28 e 90 dias. As argamassas estudadas apresentaram resistência superior em relação à da referência, até o nível de 30% de substituição.The use of burnt clays, in the metakaolin form, as pozzolanic material for mortars and concretes has received a remarkable attention in the last years. This paper aimed to evaluate the mechanical property of mortars, in which a calcined kaolin originating from the State of Paraiba, was used as partial cement replacement material. Two finess of the kaolin were used: ABNT 200 (0.074 mm and 325 (0.044 mm and burnt at temperatures of 700, 800 and 900 ºC for a period of 2 h. Both materials were characterized by chemical analysis, differential thermal analysis, X-ray diffraction, specific area tests. The pozolanic activity index was obtanied using lime and cement Portland. The amounts of replacement were 10, 20, 30 and 40%, besides the reference mortar. The binder

  2. Leaching zinc from high iron­bearing zinc calcine after selective reduction roasting%高铁锌焙砂选择性还原焙烧-两段浸出锌

    Institute of Scientific and Technical Information of China (English)

    韩俊伟; 刘维; 覃文庆; 柴立元; 郑永兴; 杨康

    2014-01-01

    Based on the decomposition of zinc ferrite to ZnO and Fe3O4 by reduction roasting, the recovery of zinc from the roasted zinc calcine was studied by two­stage leaching for zinc­iron separation and the leaching residue containing Fe3O4 was obtained. The effects of reduction roasting and conditions of neutral leaching and acid leaching on leaching rates of zinc and iron were investigated, respectively. The results show that the reduction roasting has a significant effect on recovery of zinc, and the leaching rates of Zn and Fe are about 90% and 5%, respectively. Under the following optimum conditions, which are leaching temperature of 60 ℃, liquid/solid ratio of 10:1, acid concentration of 45 g/L and leaching time of 2 h for neutral leaching, and leaching temperature of 70 ℃, liquid/solid ratio of 10:1, acid concentration of 60 g/L, stirring speed of 300 r/min and leaching time of 2 h for acid leaching. Besides, the main compositions of the residue are Fe3O4, ZnS and ZnFe2O4 according to the XRD and SEM/EDS analysis. The main reason of zinc ferrite left is attributed to the enclosure by other minerals.%采用还原焙烧将高铁锌焙砂中的铁酸锌选择性地分解为氧化锌和磁铁矿,再通过两段浸出工艺回收锌,以实现锌铁分离和获得以磁铁矿为主的浸出渣。主要考察了还原焙烧、中性浸出及低酸浸出条件对锌焙砂中锌、铁浸出率的影响。结果表明:通过还原焙烧可以显著地提高锌焙砂的锌浸出率;中性浸出的最佳条件为浸出温度60℃、液固比10:1、初始酸度45 g/L和浸出时间2 h;低酸浸出的最佳条件为浸出温度70℃、液固比10:1、初始酸度60 g/L、搅拌速度300 r/min和浸出时间2 h。在最佳条件下,两段浸出的总锌浸出率约为90%,总铁浸出率约为5%。经XRD和SEM/EDS分析,浸出渣以磁铁矿为主,其次是闪锌矿和铁酸锌;铁酸锌存在的主要原因是在还原焙

  3. STUDY OF THERMAL-DECOMPOSITION KINETICS OF Mg-Fe AND Mg-Al HYDROTALCITE WITH THE METHOD OF TEMPERATURE PROGRAMMED CALCINATION%程序升温焙烧技术研究水滑石热分解动力学

    Institute of Scientific and Technical Information of China (English)

    张维光; 葛欣; 沈俭一

    1999-01-01

    Mg-Fe and Mg-Al Hydrotalcite were prepared by the conprecipitation method. A new technique of temperature programmed calcination (TPC) is designed to investigate the thermal decomposition of the hydrotalcites. The kinetic equation of thermal decomposition ln(h/S)=lnA-Ea/RT is derived from TPC graph, and then the thermal decomposition kinetics parameters of Mg-Fe and Mg-Al hydrotalcite can be obtained. Experimental results show that this method is more definite, convenient and sensitive for characterizing the thermal decomposition process of Mg-Fe and Mg-Al Hydrotalcite. The active energy Ea of decomposition of Mg-Fe and Mg-Al hydrotalcite is about 83~48 kJ·mol-1.

  4. 焙烧程序对一步合成Cu-SSZ-13催化剂NH3-SCR性能的影响%Influence of calcination procedure on the one-pot synthesized Cu-SSZ-13 catalysts and their performance in NH3-SCR

    Institute of Scientific and Technical Information of China (English)

    谢利娟; 刘福东; 石晓燕; 贺泓

    2016-01-01

    焙烧程序影响一步合成法制备Cu-SSZ-13催化剂中Cu物种的种类及分布,是影响催化剂在NH3选择性催化还原(NH3-SCR)氮氧化物反应中催化性能的重要因素。为研究焙烧程序对该方法制备 Cu-SSZ-13催化剂性能的影响,采用不同的焙烧温度及升温速率制备 Cu-SSZ-13催化剂,并考察各催化剂的催化活性、水热稳定性及活性物种形态。结果表明焙烧温度不改变催化剂的晶型结构,但影响催化剂的活性物种形态及稳定性。当焙烧温度为600℃时,催化剂中Cu物种全部为孤立的Cu2+,并具有极高的稳定性,催化剂具有最佳的活性及水热稳定性。固定焙烧温度为600℃,随升温速率的提高,催化剂活性及水热稳定性表现出下降趋势,考虑经济成本,最佳的升温速率应为1℃/min。因此,以1℃/min的升温速率升至600℃焙烧6h是一步合成法制备Cu-SSZ-13催化剂的最佳焙烧程序,所得催化剂具备优异的NH3-SCR活性和水热稳定性。%The calcination procedures affected the state and the distribution of Cu species in the one-pot synthesized Cu-SSZ-13,which then influenced their catalytic performance greatly. In order to investigate the effect of calcination procedure on the Cu-SSZ-13 in the selective catalytic reduction of NOx by ammonia (NH3-SCR),we prepared the catalysts with different temperatures and ramp rates. The catalytic activity and hydrothermal stability and state of active species of the catalysts were tested. The calcination temperature did not change the structure of the catalyst,but affected the state and the stability of the active species. When the temperature was set at 600℃,all Cu species in the catalyst were isolated Cu2+ with excellent stability,and the catalyst showed the best catalytic performance and hydrothermal stability. When the temperature was fixed at 600℃,the activity and hydrothermal stability of the catalysts decreased with the

  5. Influence of calcination temperature on the performance of Ni/La(III) catalyst in the hydrogenolysis of sorbitol to low-carbon glycols%焙烧温度对Ni/La(Ⅲ)催化剂氢解山梨醇制备低碳二元醇性能的影响

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    Nanorod-shaped La( OH) 3 support was prepared by hydrothermal method, over which the supported Ni/La( III) catalysts were obtained through wet impregnation method; the influence of calcination temperature on the performance of Ni/La ( III ) catalyst in the hydrogenolysis of sorbitol to low-carbon glycols was then investigated by means of XRD, SEM/EDS, BET, H2-TPR-MS, CO/CO2-TPD-MS, ICP-AES and TG. The results revealed that the Ni/La ( III ) catalysts are highly active for sorbitol hydrogenolysis; the yield of low-carbon glycols reaches 53% after reaction at 220 ℃ and 4 MPa H2 for 1. 5 h. The catalyst calcined at low temperature (500℃) is mainly in the form of NiO/La2 O2 CO3 , which may transform into La2 NiO4-La2 O3 with the increase of calcination temperature. The basicity is a crucial factor for the hydrogenolysis activity; high calcionation temperature may enhance the basicity of the catalysts and then improve their hydrogenolysis activity, whereas the calcination temperature has little effect on the products selectivity. However, NiO/La2 O2 CO3 exhibits better hydrothermal stability than La2 NiO4-La2 O3 for sorbitol hydrogenolysis. The deactivation of catalysts can be attributed to the separation of active Ni particles from the support and the agglomeration of the active species, which may reduce the amount of the active metal sites and destroy the catalyst structure.%采用水热法合成了纳米棒状La(OH)3载体,通过湿式浸渍方法制备了10%Ni/La(Ⅲ)负载型催化剂,考察了500~800℃不同焙烧温度对于催化剂氢解山梨醇制备低碳二元醇的影响,结合XRD、SEM/EDS、BET、H2-TPR-MS、CO/CO2-TPD-MS、TG和ICP-AES等表征手段对Ni/La(Ⅲ)催化剂的构效关系进行了分析。结果表明,Ni/La(Ⅲ)催化剂表现出高的氢解反应活性,在较低的焙烧温度下(500℃)催化剂主要以NiO/La2 O2 CO3结构形式存在。随着焙烧温度的升高,NiO/La2 O2 CO3逐渐向La2 NiO4-La2 O3进行转变。碱性是影

  6. Depolarization temperature and piezoelectric properties of Na1/2Bi1/2TiO3–Na1/2Bi1/2(Zn1/3Nb2/3)O3 ceramics by two-stage calcination method

    Indian Academy of Sciences (India)

    Xin-Yu Liu; Chang-Rong Zhou; Zhao-Hui Shan

    2007-12-01

    A new group of NBT-based lead-free piezoelectric ceramics, Na1/2Bi1/2TiO3–Na1/2Bi1/2(Zn1/3Nb2/3)O3, was synthesized using the two-stage calcination method and depolarization temperatures and piezoelectric properties were also investigated. The XRD analysis showed that the ceramics system had a morphotropic phase boundary (MPB) between the rhombohedral and the tetragonal structure. The highest piezoelectric properties of 33 = 97 pC/N and = 0.46 were obtained near MPB compositions. Furthermore, the depolarization temperatures near MPB compositions were slightly decreased and the lowest d was maintained at 210°C.

  7. Utilização de massas cerâmicas na produção de agregado sintético de argila calcinada para uso em concreto Use of ceramic bodies in the production of synthetic aggregate calcined clay for use in concrete

    Directory of Open Access Journals (Sweden)

    E. M. Cabral

    2008-12-01

    manufacturing synthetic aggregate of calcined clay for use in concrete. The ceramic pastes were analyzed by X-ray diffraction, evaluation of chemical composition, particle size distribution and plasticity. The samples were prepared by uniaxial pressing at 20 MPa and calcined at 850, 950, 1050 and 1150 ºC. The technological properties evaluated were: linear shrinkage, water absorption, apparent specific mass and vitrification temperature. The ceramic paste that presented the smallest apparent specific mass and smallest percentile of molding humidity was chosen for synthetic aggregate. The results obtained for the concrete produced with the synthetic aggregate of calcined clay show its potential as a substitute of the natural aggregate of the Amazonic region, the natural gravel.

  8. Influence of SO2 on the cyclic calcination and carbonation of calcium-based sorbent for CO2 capture%SO2对钙基CO2吸收剂循环煅烧/碳酸化反应的影响

    Institute of Scientific and Technical Information of China (English)

    吴昊; 王萌; 刘浩; 杨宏旻

    2013-01-01

    The effects of SO2 on the cyclic calcination and carbonation characteristics and the cycling stability of calcium-based CaCO3 sorbent for CO2 capture were investigated in a cycling calcination/carbonation system. The results indicated that the capacity of CaCO3 sorbent for CO2 capture decreases with the increase of the number of calcination/carbonation cycling and the addition of SO2 will further reduce the capacity for CO2 capture; moreover, the decrease of the capacity for CO2 capture may be aggravated at higher SO2 concentration. After 10th cycling, the carbonation conversions of the sorbent under SO2 concentration of 0, 0. 1% and 0. 2% are 25.5% , 16.9% and 5.2%, respectively. SEM characterization results revealed that sulfate products are formed on the surface of CaCO3 particles in the presence of SO2; the sulfate products block the sorbent holes and then reduce the diffusion rate of CO2 into the sorbent, which may then reduce the capacity of the calcium-based sorbent for CO2 capture.%在循环煅烧/碳酸化反应系统中,研究了SO2对钙基吸收剂CaCO3捕集CO2的影响,获得了SO2对钙基吸收剂碳酸化特性、煅烧特性以及循环稳定性的影响规律,并结合SEM分析结果,从循环煅烧/碳酸化反应角度,分析了可能存在的原因.结果表明,钙基吸收剂吸收CO2的能力随着循环反应次数的增加逐渐发生衰减,在SO2影响下,这种衰减会进一步加剧,且衰减程度随着SO2浓度的增加而增大,经过十次循环后,碳酸化转化率分别为25.5% (0% SO2)、16.9% (0.1%SO2)和5.2%(0.2% SO2).造成这种衰减加剧的主要原因是反应产生较厚的硫酸化产物层,硫酸化产物层使颗粒表面孔隙发生堵塞,阻碍了CO2在吸收剂内部的扩散,降低了碳酸化转化率.

  9. 供能方式对钙基吸收剂循环煅烧/碳酸化法捕集CO2热力性能的影响%Influence of Energy Supply Mode on Thermodynamic Performance of CO2 Capture Systems With Ca-based Sorbent Cyclic Calcination/Carbonation Reaction

    Institute of Scientific and Technical Information of China (English)

    张学镭; 陈海平

    2013-01-01

    Capturing CO2 from fossil fuel combustion is of importance in the CO2-constrained world for mitigation of climate warming. Take an ultra-supercritical 1000MW power plant as an example, the flow sheet of CO2 capture system with Ca-based sorbent cyclic calcination/carbonation reaction was built, and the thermodynamic performance of CO2 capture system was obtained by the help of Aspen Plus software. The influence of CaCO3 calcination reaction heat supplied by concentrated solar power or coal oxy-fired on thermodynamic performance was also analyzed. The results show that compared with coal oxy-fired scheme, concentrated solar power scheme increases the output power, decreases standard coal consumption rate by 1/3, but thermal efficiency of power generation is decreased by 3.8 percentage points. The equivalent solar thermal power efficiency of concentrated solar power scheme is 28.36%, which is higher than peak efficiency of solar tower power plant. The key factor to increase thermodynamic performance of concentrated solar power scheme is energy utilization efficiency (ηsol-avi) of the solar collector field. Asηsol-avi>75%, power generation efficiency of concentrated solar power scheme is higher than that of coal oxy-fired scheme. The conclusions supply new schemes for low energy consume of CO2 capture and high efficiency utilization of solar power.%控制和减缓化石能源燃烧所排放的 CO2对于缓解全球气候变暖具有重要意义。以某超超临界1000 MW火力发电机组为例,建立了钙基吸收剂循环煅烧/碳酸化法捕集CO2的系统流程,基于Aspen Plus软件得到了系统的热力性能,分析了太阳能集热和煤富氧燃烧驱动 CaCO3煅烧反应对系统热力性能的影响。结果表明,与煤富氧燃烧方案相比,太阳能集热方案增加了发电功率,发电标准煤耗率降低1/3,但其发电热效率降低3.8个百分点;太阳能集热方案的等效太阳能热发电效率为28.36%,高于塔

  10. Study on the Photocatalytic Activities of n-p Type CeO2/BiOBr Composite Prepared at Different Calcination Temperatures%不同煅烧温度制备的n-p型CeO2/BiOBr光催化性能研究

    Institute of Scientific and Technical Information of China (English)

    曹亚亚; 黄少斌; 尹佳芝

    2016-01-01

    采用微乳法制备了n-p型CeO2/BiOBr 异质结,其中十六烷基三甲基溴化铵(CTAB)既作为Br源,又作为“桥”使CTA+修饰在CeO2表面形成了稳定的油包水微乳体系.利用XRD、SEM、HRTEM、UV-Vis DRS、BET、XPS等对样品进行结构、形貌和光学性质进行表征,并对复合光催化剂进行了可见光下降解甲基橙(MO)的光催化活性研究.考察了不同煅烧温度对合成CeO2/BiOBr的影响.结果表明:CeO2/BiOBr异质结相比于单体CeO2和BiO-Br来说,它的光响应范围大大增加,在可见光下降解MO具有更高的光催化活性.450℃下煅烧可使MO达到最佳的降解率,而高温则会使催化剂发生烧结.机理研究表明,在CeO2与BiOBr复合体中,使有机物矿化的主要为CeO2价带上的光生空穴.CeO2/BiOBr催化活性增强主要是由于在CeO2与BiOBr之间形成了n-p型的异质结.%N-p type CeO2/BiOBr heterojunction was prepared using microemulsion method,in which cetyltrimethyl ammonium bromide (CTAB)acted not only as the Br source,but was able to link the cetyltrimethyl ammonium cation with CeO2 to form a water-in-oil microemulsion-like system.Several characterization tools including XRD, SEM,HRTEM,UV-Vis DRS,BET and XPS were employed to study the phase structures,morphologies and opti-cal properties of the samples.Methyl orange (MO)solutions were used to degrade by the prepared composite pho-tocatalysts and evaluate the photocatalytic activities under visible light irradiation. The results show that in compared to pure CeO2 and BiOBr,the heterojunction exhibits enhanced absorption response in visible light range and higher photocatalytic performance for the degradation of MO.The CeO2/BiOBr compsite calcinated at 450 ℃exhibits the optical degradation rate of MO under visible light irradiation,while high temperature calcination can lead to sinter of photocatalyst.The study on mechanism shows that the CeO2/Bi

  11. 焙烧处理下二氧化钛/钛酸盐纳米材料晶型和形貌的变化规律研究%Research on the Phase Transition and Morphological Evolution Behaviors of Titania/Titanate Nanomaterials by Calcination Treatment

    Institute of Scientific and Technical Information of China (English)

    赵斌; 林琳; 陈超; 柴瑜超; 何丹农

    2013-01-01

    通过调控酸碱浓度,在水热条件下得到了金红石、锐钛矿、板钛矿、钛酸钠等一系列TiO2/钛酸盐产物.对上述TiO2、酸洗处理后的钛酸盐等一系列不同晶型、不同形貌的样品进行焙烧处理,系统性地研究焙烧温度的逐渐升高对产物晶型转变和形貌演化的规律性影响.给出了水热酸碱浓度以及焙烧温度两个因素与TiO2/钛酸盐纳米材料晶型和形貌变化行为关系的二维示意图.依据奥斯特瓦尔德阶梯规则、经典热力学理论以及定向附着生长机理,对TiO2/钛酸产物的晶型晶体生长、晶型转变和形貌演化机理进行了探讨.%Titania/titanate nanomaterials including rutile, anatase, brookite TiO2 and sodium dititanate and trititanate were obtained by regulating the acid/alkali concentration under hydrothermal treatment. A systematical investigation was established to uncover the phase transition and morphological evolution behaviors of TiO2/titanate nanomaterials by calcining the samples including rutile TiO2 nanorods, anatase TiO2 nanocrystallines, brookite TiO2 nanoflowers, acid washed dititanate H2Ti2O5 nanosheets and trititanate H2Ti3O7 nanowires at 400, 600, 800 or 1000 ℃ for 4 h in air with the heating rate of 2 ℃/min. After heat-treatment, the products were taken out from the oven and cooled down to the room temperature. Rietveld refinements of the powder X-ray diffraction (XRD) pattern were used to generally assess the phase composition of the different samples and their crystallite sizes, and to further investigate the phase transition behavior in company with the synthetic parameters. FESEM, TEM, and HRTEM were used to characterize the morphology evolution and to further elucidate the morphological evolution of the resulting products. The crystalline phase distributed diagram of TiO2/titanate nanostruc-tures dominated by the two experimental parameters indcluding acid/alkali concentration and calcination temperature was

  12. Calcination of kaolinite clay particles for cement production

    DEFF Research Database (Denmark)

    Gebremariam, Abraham Teklay; Yin, Chungen; Rosendahl, Lasse;

    2014-01-01

    considered in the model include dehydration, dehydroxylation and various phase transformations. Thermogravimetric analysis is used to determine reaction kinetic data required as inputs in the model and to validate the model. Finally, model-based sensitivity analysis is performed, from which quantitative...

  13. Fluidized-bed calciner with combustion nozzle and shroud

    Science.gov (United States)

    Wielang, Joseph A.; Palmer, William B.; Kerr, William B.

    1977-01-01

    A nozzle employed as a burner within a fluidized bed is coaxially enclosed within a tubular shroud that extends beyond the nozzle length into the fluidized bed. The open-ended shroud portion beyond the nozzle end provides an antechamber for mixture and combustion of atomized fuel with an oxygen-containing gas. The arrangement provides improved combustion efficiency and excludes bed particles from the high-velocity, high-temperature portions of the flame to reduce particle attrition.

  14. Toxicity study of Lauha Bhasma (calcined iron in albino rats

    Directory of Open Access Journals (Sweden)

    Namrata Joshi

    2016-01-01

    Conclusion: Lauha Bhasma was found to be safe at the therapeutic dose and also at five times the therapeutic dose levels. However, alteration in some of the biochemical and haematological parameters along with histopathological findings were evident at the highest dose level.

  15. Influence of Calcination Temperature on Performances of Co-N/C Electrocatalysts for Li/O2 Cells%热处理温度对锂氧气电池用Co-N/C催化剂催化性能的影响

    Institute of Scientific and Technical Information of China (English)

    阳炳检; 王红; 李磊; 黄博文; 廖小珍; 何雨石; 马紫峰

    2014-01-01

    The development of low-cost and effective electrocatalysts for air electrodes is critical for practical applications of lithium/oxygen batteries. In the present work, phenanthroline (phen) was used as a ligand to prepare a Co(phen)2 complex. The Co(phen)2 complex was coated on BP2000 and then heat treated at 600, 700, 800, and 900 °C, to obtain carbon-supported Co-N (Co-N/C) catalysts. The catalytic activities in oxygen reduction reaction/oxygen evolution reaction (ORR/OER) of the prepared catalysts were measured and compared with those of a typical carbon-supported cobalt tetramethoxyphenylporphyrin (CoTMPP/C) catalyst. The influence of the calcination temperature on the composition and structure of the Co-N/C catalysts was investigated. Electrochemical tests showed that the Co-N/C catalysts prepared at 700 and 800 °C gave better performances, comparable to that of the CoTMPP/C catalyst. The superior electrochemical performance of the prepared Co-N/C catalysts and the low cost of the phenanthroline chelating agent make Co-N/C a promising cheap catalyst for lithium/oxygen batteries.%开发低成本、高效的空气电极催化剂是发展锂空气电池的关键课题之一。采用邻菲咯啉(phen)为配体制备Co(phen)2配合物,负载于BP2000碳载体上,并分别在600、700、800和900°C的温度下进行热处理,制备得到碳支撑的Co-N催化剂(Co-N/C)。对催化剂的氧还原反应/析氧反应(ORR/OER)活性进行了表征,并且与典型的CoTMPP/C催化剂进行了比较。同时研究了煅烧温度对Co-N/C催化剂的组成和结构的影响。电化学测试结果表明,热处理温度为700-800°C时催化剂具有较好的电化学性能。 Co-N/C催化剂具有电化学性能优良与低成本的特点,是一种良好的锂氧气电池催化剂。

  16. 水蒸气改善钙基CO2吸收剂循环活性的研究%Study on the improvement of the carbonation characteristics of Ca-based CO2 absorbent by steam repetitive calcination-carbonation

    Institute of Scientific and Technical Information of China (English)

    乔春珍; 陈伟娇

    2012-01-01

    Repetitive calcination-carbonation of Ca-based CO2 absorbent with adding steam was performed experimentally to investigate the effect of steam on the cyclic characteristics of Ca-based CO2 absorbent. The maximum conversion rate, pore radius and specific surface area microstructure of hydrated Ca-based CO2 absorbent was analyzed. Results showed that the cyclic characteristics of the hydrated Ca-based CO2 absorbent was improved, the maximum conversion of Ca-based CO; absorbent was increased by 50 % than dry ones. The reason was that the steam treatment could greatly increase the specific surface area of the absorbent and improve the distributions of pore radius. From the experiment we can conclude that direct hydrogen production by carbon energy could be realized without any additives or auxiliary conditions, which would meatain the cyclic activity of Ca-based CO2 absorbent.%对钙基CO2吸收剂的循环活性改善进行了研究,分析了水蒸气处理对吸收剂的最大转化率、比表面积及孔分布等微观结构变化的影响.结果表明,经水蒸气处理后,钙基CO2吸收剂的循环活性得到了改善,最大转化率比未经水蒸气处理可提高约50百分点;水蒸气处理可大大提高钙基CO2吸收剂的比表面积,并有效改善其孔径分布状态,可使其稳定保持较高的转化率;含碳能源直接制氢过程可在不需要任何添加剂或辅助手段的条件下,有效保持钙基CO2吸收剂的循环活性.

  17. Effect of calcination temperature on K modified Ag-Fe/ZnO-ZrO2 catalyst structure and its performance for higher alcohols and DME synthesis fro m CO hydrogenation%焙烧温度对K改性Ag-Fe/ZnO-ZrO2催化剂结构和CO加氢合成低碳混合醇醚性能的影响

    Institute of Scientific and Technical Information of China (English)

    冉磊; 华金铭; 魏可镁

    2015-01-01

    采用并流共沉淀法在不同焙烧温度下制备 K 改性 Ag-Fe/ZnO-ZrO2催化剂,考察不同焙烧温度对催化剂 CO 加氢合成低碳混合醇醚反应性能的影响。通过 N2物理吸附(N2-adsorption)、X 射线衍射(XRD)、氢气程序升温还原(H2-TPR)、一氧化碳程序升温脱附(CO-TPD)等手段对催化剂进行表征。结果表明,250℃焙烧的催化剂,由于焙烧温度较低,表面尚未形成足够多的活性位,未能达到最佳的催化性能;300℃焙烧的催化剂,其 CO 转化率最高、醇醚选择性较高,醇醚时空产率达到最大值。随着焙烧温度进一步升高,CO 转化率逐渐降低,醇选择性先降低后增大,二甲醚(DME)选择性逐渐增大,醇醚时空产率逐渐降低。催化剂性能主要与其比表面积、还原性能、所含银铁复合物分散度及 CO 吸脱附性能有关,即比表面积较大、易于被还原、银铁复合物分散度较高以及较多的 CO 吸脱附活性位,有利于催化剂 CO 加氢转化。催化剂表面活性位对 CO 的非解离吸附强度降低,有利于醇醚产物的生成;而对 CO 的解离吸附强度增强,则不利于烃类产物的生成。%A series of K modif ed Ag-Fe/ZnO-ZrO2 catalysts were prepared by co-precipitation method under different calcination temperatures.The ef fect ofc alcination temperature on the catalytic performance for higher alcohols and dimethyl ether ( DME) synthesis from CO hydrogenation was investigated.The catalysts were characterized by nitrogen adsorption, XRD, H2-TPR and CO-TPD.The results s howed that the catalyst calcined at 250 ℃ coul d not rea ch the optimal performance due to insufficient active site s formed at the lower calcination temperature.The catalyst calcined at 300 ℃ exhibited highest CO conversion and higher selectivity of higher alcohols and DME and highest space time yield of higher alcohols and DME reached.As the

  18. Effects of calcining process and CeO2 on properties of (1-x)LaAlO3-xCaTiO3 microwave dielectric ceramics%预烧工艺和CeO2添加剂对(1-x)LaAlO3-xCaTiO3微波介质陶瓷性能的影响

    Institute of Scientific and Technical Information of China (English)

    薛田良; 付云侠; 夏俊芳

    2012-01-01

    利用常规固相法制备了[(1-x)LaAlO3-xCaTiO3]+yCeO2陶瓷(y为CeO2的质量分数),研究了预烧工艺和CeO2添加剂对所制陶瓷微波介电性能的影响.结果表明,LaAlO3与CaTiO3一次预烧能获得较好的微波介电性能,CeO2添加剂能有效提高材料的烧结性能和微波介电性能.(0.4LaAlO3-0.6CaTiO3)+0.2%CeO2陶瓷经1 450℃烧结5h后能获得最佳微波介电性能:εr=43.1、Q·f=29 700 GHz、τf=-2.4×10-6/℃.%[(l-x)LaA1O3-xCaTi03]+yCe02 ceramics(y was mass fraction of CeO2) were prepared by the solid-state reaction. The effects of calcining process and CeO2 addition on microwave dielectric properties of the [(l-x)LaA103-xCaTi03]+yCe02 ceramics were investigated. It shows that more excellent microwave dielectric properties are obtained when LaAlO3 and CaTiO3 are calcined together, and CeO2 addition can improve effectively the sinterablity and microwave dielectric properties of [(l-x)LaA103-xCaTi03]+yCe02 ceramics. (0.4LaAlO3-0.6CaTiO3)+0.2%CeO2 ceramics sintered at 1 450 ℃ for 5 h has best microwave dielectric properties with er of 43.1, Q ·f o f29 700 GHz and tfof-2.4× 10-6/ ℃.

  19. Efecto de la concentración de SO2 en las reacciones de calcinación y sulfatación de calcáreos en reactores de lecho fluidizado. // Effect of the SO2 concentration in the calcinations and sulfatation reactions in a fluidized bed reactor.

    Directory of Open Access Journals (Sweden)

    J. E. Lindo Samaniego

    2008-01-01

    Full Text Available Fue realizado un estudio sobre el efecto de las concentraciones de SO2 en la absorción por calcáreo en hornos de LechoFluidizado. Para observar la influencia del SO2 en los parámetros de diferentes procesos físicos y químicos fueron creadosambientes para cuatro concentraciones diferentes de SO2 : 500, 1000, 2000 y 4000 ppm. Se utilizaron dos tipos decalcáreos: Dolimitico-DP y el Calcítico-CI. El Lecho Fluidizado Burbujeante utilizado tiene 160 mm de diámetro interno yfue fluidizado con aire a la temperatura de 850 °C, con una concentración de SO2 deseada. Como material del lecho fueutilizada la arena de cuarzo (99,9% con diámetro de 385 μm y de masa aproximadamente 3,0 kg. El calcáreo fueadicionado en dosificación de 50 g con el reactor ya pre-calentado. Las variaciones de las concentraciones de SO2, CO2,CO, O2 y las descargas, fueron monitoreadas continuamente a la salida del ciclón que fue utilizado para la retención de lapartícula fina. Para esos dados se desarrolló un programa en LabView. El modelo matemático escogido posibilitó ladeterminación de la conversión.Palabras claves: Lecho fluidizado, dióxido de azufre, absorción de azufre, calcáreo , reactor de lechofluidizado.___________________________________________________________________________Abstract.A Study of the effect of the concentrations of SO2 in its absorption by limestones in fluidized bed furnaces wasconducted. For the determination of the SO2 influence on the different physical and chemical parameters of process,such as calcinations and sulfatation four different atmospheres were used in the reator with concentrations of SO2 of500, 1000, 2000 and 4000 ppm. Two types of limestones were used: Dolomite-DP and Calcitic-CI. The bench scalebubbling fluidized bed reactor had a 160 mm internal diameter and was fluidized with air at 850 °C containing therequired concentration of SO2. Bed material was quartz sand (99,9% , with 385 μm diameter and approximately

  20. Influence of cobalt nitrate concentration in the calcination temperature and time for synthesis of La{sub 0,60S}r{sub 0,40C}o{sub 0,20F}e{sub 0,80O3}; Influencia da concentracao de nitrato de cobalto na temperatura e tempo de calcinacao para a sintese do La{sub 0,60S}r{sub 0,40C}o{sub 0,20F}e{sub 0,80O3}

    Energy Technology Data Exchange (ETDEWEB)

    Vargas, R.A.; Bonturim, E.; Andreoli, M.; Chiba, R.; Seo, E.S.M., E-mail: ravargas@usp.b [Instituto de Pesquisas Energeticas e Nucleares (CCTM/IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Ciencia e Tecnologia de Materiais. Lab. de SOFC: Insumos e Componentes

    2010-07-01

    The La({sub 1-x})Sr{sub x}Co({sub 1-y})Fe{sub y}O{sub 3} (LSCF) has been highlighted as a excellent cathode for Intermediate Temperature Solid Oxide Fuel Cells, due to the high catalytic activity and good ionic and electronic conductivity. This work presents some characteristics of LSCF particle with regard of nitrate excess cobalt influence in the synthesis which different temperatures (700, 800, 900 and 1000 deg C) and times (2, 3 and 4h) calcination. The material was synthesized by citrate technique and analysis for XRF to confirmed the formation of nominal composition (x=0,40 and y=0,80). The micrographs showed the grain sized distribution disclosed particle accumulations, with 0,50 mum inferior average sizes. It was verified for TGA that the LSCF is synthesized above at 700 deg C and for XRD the studied formation of the main phase pseudo-orthorhombic structure in temperatures and times studied.(author)

  1. Effect of Calcining Temperature on the Structure of Li_4Ti_5O_(12)

    Institute of Scientific and Technical Information of China (English)

    G.J.Wang; N.H.Zhao; L.J.Fu; B.Wang; Y.P.Wu

    2007-01-01

    1 Introduction Recently there had considerable interest in Li4Ti5O12 as a potential anode for use in Li-ion batteries. Usually, it was used as an anode combined with a high voltage cathode[1-5]. It has many advantages compared to the currently used graphite. For example, it presents virtually unlimited cycle life due to zero strain or volume change when lithium intercalates into and de-intercalates from[6]. Generally, Li4Ti5O12 was prepared by a solid-state reaction from stoichiometric amounts of Li2CO3...

  2. Effect of Calcination on the Sintering of Gel-Derived, Zirconia-Toughened Alumina

    NARCIS (Netherlands)

    Exter, den Peter; Winnubst, Louis; Leuwerink, Theo H.P.; Burggraaf, Anthonie J.

    1994-01-01

    The densification behavior of ZrO2 (+ 3 mol% Y2O3)/85 wt% Al2O3 powder compacts, prepared by the hydrolysis of metal chlorides, can be characterized by a transition- and an α-alumina densification stage. The sintering behavior is strongly determined by the densification of the transition alumina agg

  3. Ultrasound with low intensity assisted the synthesis of nanocrystalline TiO2 without calcination.

    Science.gov (United States)

    Ghows, Narjes; Entezari, Mohamad H

    2010-06-01

    A novel method has been developed for the preparation of nano-sized TiO(2) with anatase phase. Nanoparticles with diameter about 6 nm were prepared at a relatively low temperature (75 degrees C) and short time. The synthesis was carried out by the hydrolysis of titanium tetra-isopropoxide (TTIP) in the presence of water, ethanol, and dispersant under ultrasonic irradiation (500 kHz) at low intensity. The results show that variables such as water/ethanol ratio, irradiation time, and temperature have a great influence on the particle size and crystalline phases of TiO(2) nanoparticles. Characterization of the product was carried out by different techniques such as powder X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and UV-vis spectroscopy. PMID:20382553

  4. Conception of a synthesis pozzolan from sediment dams calcined (Case: Gargar dams

    Directory of Open Access Journals (Sweden)

    Ouhba K.

    2014-04-01

    The analysis by the diffraction of x-rays (X-ray and the differential thermal analysis (DTA show that the chemical reactions between principal minerals of the vase used and cement give the formation of new products such as the freezing of HSC and the tobermorite.

  5. CALCinATION OF EQUILIBRIUM FOR DIMETHYL ETHER SYNTHESIS FROM BIOMASS-SYNGAS%生物质气一步法合成二甲醚化学平衡分析

    Institute of Scientific and Technical Information of China (English)

    许庆利; 蓝平; 隋淼; 颜涌捷

    2011-01-01

    Thermodynamic calculation was carried out for the compound reaction system of dimethyl ether (DME) from biomass-syngas. Methanol synthesis from CO, CO2, and dehydration of metlanol to DME were selected as the independent reactions, CO, CO2 and DME were chosen as the key components. At the same time, the calculated model about DME synthesis was put forward. The article discussed the effect of temperature and pressure on the chemical balance of biomass synthesis of DME. The results showed that the equilibrium conversion of CO and the equilibrium yield of DME decrease with the increase of temper, and increase with the increase of pressure.%对生物质基合成气合成二甲醚反应体系进行热力学参数计算.选取CO、CO2加氢合成甲醇及甲醇脱水生成二甲醚为独立反应,CO、CO2、二甲醚为关键组分,提出了合成气合成二甲醚的计算模型.讨论了温度、压力对生物质气合成二甲醚化学平衡的影响.结果表明:CO平衡转化率、DME平衡收率随温度的升高而下降;随压力升高,CO平衡转化率、DME平衡收率增加.

  6. Microscopic evolution of dielectric nanoparticles at different calcination temperatures synthesized via sol-gel auto-combustion

    International Nuclear Information System (INIS)

    Dielectric nano powder synthesis is carried by a simple and fast sol-gel auto-combustion method. The transformation of crystalline phases of as-synthesized nano powders is investigated through the detailed transmission electron microscopy (TEM), revealed the crystallographic alterations and morphological information even at lattice scale. From specific area electron diffraction (SAED) pattern, has specified the d-spacing and corresponding planes supported by the observed lattice fringes. The morphological characterization of nanoparticles is performed through field-emission scanning electron microscopy (FESEM), exhibiting the increment in particle size due to agglomeration with the increase in annealing temperature. Furthermore, EDX pattern has been used to verify the formation of nanoparticles by revealing the presence of required elements

  7. Beneficiation of Low-Grade Phosphate Deposits by a Combination of Calcination and Shaking Tables: Southwest Iran

    OpenAIRE

    Shahram Shariati; Aisan Ramadi; Armin Salsani

    2015-01-01

    Three quarters of the world’s phosphate deposits are of sedimentary origin and 75%–80% of those include carbonate gangue. In this study, carbonate sedimentary phosphate deposits of the Lar Mountains of southwest Iran are studied. These deposits consist mainly of calcite, fluorapatite, quartz, kaolinite and illite, with an average P2O5 grade of 9%–10% (low-grade). Various pre-processing and processing methods have been developed for concentrating low-grade phosphate up to marketable grade and ...

  8. Mass Transfer and Reaction Kinetics in the Carbonization of Magnesium Oxide from Light Calcined Magnesia with Mechanical Force Enhancement

    Institute of Scientific and Technical Information of China (English)

    张焕军; 朱国才

    2004-01-01

    The carbonization of magnesium oxide particles by CO2 was investigated using a stirring mill reactor.The effects of the system temperature, stirring rotation speed, influx rate of CO2 and initial diameter of the magnesium oxide particles on the carbonization process were determined. The results show that the system temperature and the stirring rotation speed are the most significant influencing factors on the carbonization rate. The determination of critical decomposition temperature (CDT) gives the maximum carbonization rate with other conditions fixed. A theoretical model involving mass transfer and reaction kinetics was presented for the carbonization process.The apparent activation energy was calculated to be 32.8kJ·mo1-1. The carbonization process is co-controlled by diffusive mass transfer and chemical reaction. The model fits well with the experimental results.

  9. Microscopic evolution of dielectric nanoparticles at different calcination temperatures synthesized via sol-gel auto-combustion

    Energy Technology Data Exchange (ETDEWEB)

    Adil, Muhammad, E-mail: muhammadadil86@hotmail.com; Zaid, Hasnah Mohd, E-mail: hasnamz@petronas.com.my; Chuan, Lee Kean, E-mail: lee.kc@petronas.com.my; Latiff, Noor Rasyada Ahmad, E-mail: syasya.latiff@gmail.com [Fundamental and Applied Sciences Department, Universiti Teknologi PETRONAS Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia); Alta’ee, Ali F., E-mail: ali-mangi@petronas.com.my [Geoscience and Petroleum Engineering Department, Universiti Teknologi PETRONAS Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia)

    2015-07-22

    Dielectric nano powder synthesis is carried by a simple and fast sol-gel auto-combustion method. The transformation of crystalline phases of as-synthesized nano powders is investigated through the detailed transmission electron microscopy (TEM), revealed the crystallographic alterations and morphological information even at lattice scale. From specific area electron diffraction (SAED) pattern, has specified the d-spacing and corresponding planes supported by the observed lattice fringes. The morphological characterization of nanoparticles is performed through field-emission scanning electron microscopy (FESEM), exhibiting the increment in particle size due to agglomeration with the increase in annealing temperature. Furthermore, EDX pattern has been used to verify the formation of nanoparticles by revealing the presence of required elements.

  10. Development of preheater and calciner (Part Ⅲ)%预热器和分解炉的发展(三)

    Institute of Scientific and Technical Information of China (English)

    熊会思

    2003-01-01

    @@ 2.2.2 日本川崎重工KSV炉系列 KSV是Kawasaki Spouted Bed and Vortex Chamber的缩写,意即川崎喷腾层涡流炉.川崎重工是日本重要水泥装备供应商之一、自行开发了KSV分解炉系列. 2.2.2 .1 川崎重工KSV分解炉 日本川崎重工业公司1973年在日本德山曹达公司建造了第一台3 200 t/d的KSV窑(图18),以后发展成N-KSV窑,我国建材科学研究院与本溪水泥厂合作,开发BX型分解炉与KSV类似,后来我国朝阳重型机器厂购买了N-KSV制造专利.

  11. THIRD ANNUAL REPORT. PHYSICAL, CHEMICAL AND STRUCTURAL EVOLUTION OF ZEOLITE-CONTAINING WASTE FORMS PRODUCED FROM METAKAOLINITE AND CALCINED HLW

    Science.gov (United States)

    Natural and synthetic zeolites are extremely versatile materials. They can adsorb a variety of liquids and gasses, and take part in cation exchange reactions. Zeolites are relatively easy to synthesize from a wide range of natural and man-made materials. One such combination is a...

  12. PHYSICAL, CHEMICAL AND STRUCTURAL EVOLUTION OF ZEOLITE-CONTAINING WASTE FORMS PRODUCED FROM METAKAOLINITE AND CALCINED HLW

    Science.gov (United States)

    Natural and synthetic zeolites are extreme versatile materials. They can adsorb a variety of liquids and gases, and also take part in cation exchange reactions. Zeolites are easy to make, they can be synthesized from a wide variety of natural and man made materials. One such c...

  13. High calcination of ferroelectric BaTiO3 doped Fe nanoceramics prepared by a solid-state sintering method

    Science.gov (United States)

    Samuvel, K.; Ramachandran, K.

    2015-07-01

    This study examined the effects of the combination of starting materials on the properties of solid-state reacted BaTiO3 using two different types of BaCO3 and TiO2. In addition, the effect of mechanochemical activation by high energy milling and the Ba/Ti molar ratio on the reaction temperature, particle size and tetragonality were investigated. The TiO2 phase and size plays a major role in increasing the reaction temperature and particle size. With the optimum selection of starting materials and processing conditions, BaTiO3 with a particle size Cole-Cole plots in complex impedance and modulus formalism. Modulus formalism has identified the effects of both grain and grain boundary microstructure on the dielectric properties, particularly in solid state routed samples.

  14. High calcination of ferroelectric BaTiO₃ doped Fe nanoceramics prepared by a solid-state sintering method.

    Science.gov (United States)

    Samuvel, K; Ramachandran, K

    2015-07-01

    This study examined the effects of the combination of starting materials on the properties of solid-state reacted BaTiO3 using two different types of BaCO3 and TiO2. In addition, the effect of mechanochemical activation by high energy milling and the Ba/Ti molar ratio on the reaction temperature, particle size and tetragonality were investigated. The TiO2 phase and size plays a major role in increasing the reaction temperature and particle size. With the optimum selection of starting materials and processing conditions, BaTiO3 with a particle size Cole-Cole plots in complex impedance and modulus formalism. Modulus formalism has identified the effects of both grain and grain boundary microstructure on the dielectric properties, particularly in solid state routed samples.

  15. Effects of various calcined ash and sludge waste loadings on the durability of a soda-lime-silica glass

    International Nuclear Information System (INIS)

    A commercially available joule-heated glass furnace system is currently being evaluated at Mound as a means of reducing the volume of low-level radioactive waste similar to that found in light water reactor facilities. The furnace utilizes molten soda-lime-silica to initiate and support combustion of the waste feed and to serve as an immobilization matrix. First, corrosion studies were performed to determine the result that various waste loadings of glass would have on the refractory lining the furnace. Second, the chemical durability of soda-lime-silica under various waste loadings was assessed to determine its resistance to leaching under conditions similar to those encountered at waste disposal sites. Results proved that, although corrosion was quite significant for pure soda-lime-silica and a 10% waste loading, by the time a waste loading of 40% was achieved, the effects of corrosion were virtually nil. The temperature dependence of the corrosion caused by a 0% waste loading of soda-lime-silica on the refractory was also investigated. With an increase in temperature to 26500F, corrosion more than tripled. As a result, incineration and idle temperature is being maintained at, or below, 24000F. In conclusion, from the fact that the higher waste loading of soda-lime glass produced both increased chemical durability and increased refractory life, waste loadings in excess of 40%, and as high as 80%, may be achieved without adverse effect to the glass furnace system or its effectiveness for immobilizing radioactive waste

  16. 预分解窑试烧危险废弃物%Study of precalener kiln calcinated danger wastes

    Institute of Scientific and Technical Information of China (English)

    沈鑫根; 肖镇; 杨盛林

    2002-01-01

      北京水泥厂是我国自行开发设计的一条2000t/d新型干法预分解窑生产线,熟料烧成系统为双系列五级旋风预热器,D-D型分解炉,φ4m×60m回转窑、篦式冷却机,窑尾设有喷雾降温的废气冷却塔和大型袋式收尘器.……

  17. Physical, Chemical and Structural Evolution of Zeolite-Containing Waste Forms Produced from Metakaolinite and Calcined Sodium Bearing Waste (HLW and/or LLW)

    Energy Technology Data Exchange (ETDEWEB)

    Grutzeck, Michael W.

    2005-06-27

    Zeolites are extremely versatile. They can adsorb liquids and gases and serve as cation exchange media. They occur in nature as well cemented deposits. The ancient Romans used blocks of zeolitized tuff as a building material. Using zeolites for the management of radioactive waste is not a new idea, but a process by which the zeolites can be made to act as a cementing agent is. Zeolitic materials are relatively easy to synthesize from a wide range of both natural and man-made substances. The process under study is derived from a well known method in which metakaolin (an impure thermally dehydroxylated kaolinite heated to {approx}700 C containing traces of quartz and mica) is mixed with sodium hydroxide (NaOH) and reacted in slurry form (for a day or two) at mildly elevated temperatures. The zeolites form as finely divided powders containing micrometer ({micro}m) sized crystals. However, if the process is changed slightly and only just enough concentrated sodium hydroxide solution is added to the metakaolinite to make a thick crumbly paste and then the paste is compacted and cured under mild hydrothermal conditions (60-200 C), the mixture will form a hard ceramic-like material containing distinct crystalline tectosilicate minerals (zeolites and feldspathoids) imbedded in an X-ray amorphous hydrated sodium aluminosilicate matrix. Due to its lack of porosity and vitreous appearance we have chosen to call this composite a ''hydroceramic''.

  18. The Effect of Calcination Temperature on Synthesis of B4C-Nano Tib2 Composite by Co-Precipitation Method

    Directory of Open Access Journals (Sweden)

    Saeid Abedini Khorrami

    2016-08-01

    Full Text Available Titanium diboride is one of the candidate materials for high temperature applications and also for control rod elements in high temperature reactors. This paper presents the experimental data on the composites of B4C-nano TiB2 that were synthesized successfully by co-precipitation method at temperatures between 973 and 1523K. Titanium tetraisopropoxide, boron carbide and isopropanol were used as the precursor materials. The phase constitution and microstructure of B4C-nano TiB2 during synthesis were investigated. X-ray diffraction (XRD and scanning electron microscopy (SEM were used to determine phase and microstructure of TiB2-B4C composites. The DTA/DDTA and TG/DTG results improve that the first exothermic reaction is TiO2 phase and second exothermic reaction takes place at 1523K which is TiB2 phase

  19. Use of calcined layered double hydroxides for the removal of color and organic matter from textile effluents: kinetic, equilibrium and recycling studies

    Directory of Open Access Journals (Sweden)

    T. P. F. Teixeira

    2014-03-01

    Full Text Available This paper presents data for the synthesis and characterization of layer double hydroxides (LDH and their use for color and chemical oxygen demand (COD removal from effluents generated by a textile industry. Adsorption studies with raw and biologically treated (activated sludge textile effluent showed that the pseudo-second order model best fitted the experimental data, leading to adsorption coefficients of 39.1 and 102.9 mgCOD/gLDH for raw and treated effluents, respectively. The best conditions for color and COD removal were obtained at lower values of temperature and pH (25 °C and pH 7 and, in these conditions, an LDH dose of 10 g/L resulted in color removal efficiencies of 56% for samples of raw and 66% for samples of treated effluent. Recycling studies indicated that the reuse of thermally treated LDH led to a progressive loss in the removal efficiencies of COD and color. The reduction was more pronounced with samples of the raw textile effluent. LDH characterization performed before and after each adsorption and regeneration experiment showed that there was no intercalation of dye molecules in the interlayer region of the LDH, indicating that COD and color removal might be due to the adsorption of organic molecules onto the LDH surface.

  20. Effect Study of Sodium Citrate on Flue Gas Desulfurization Calcined Gypsum%柠檬酸钠对脱硫建筑石膏的影响研究

    Institute of Scientific and Technical Information of China (English)

    钟雯; 赵云龙; 刘鹏强; 张清; 米宏成

    2015-01-01

    研究了不同柠檬酸钠掺量对脱硫建筑石膏的力学性能及缓凝效果的影响.试验结果表明:随着柠檬酸钠掺量不断增大,缓凝时间越长,强度损失越大,且强度损失和缓凝效果几乎成正比.