WorldWideScience

Sample records for indirect bio leaching

  1. Copper recovery from slag by indirect bio leaching

    International Nuclear Information System (INIS)

    Mazuelos, A.; Iglesias, N.; Romero, R.; Forcat, O.; Carranza, F.

    2009-01-01

    The main source of copper loss from a smelter is copper in discard slag. Slag can contain Cu in concentrations very much higher than those of many ores. Cu is present in slag entrained in very small drops of matte, white metal and blister copper occluded in fayalitic phase. In this work, the technical viability of the BRISA process, that is based on the indirect bio leaching, for this residue has been proved. A sample of slag, containing 2 % of copper, has been chemical, granulometric and metallographic characterized and it has been leached with ferric sulphate solutions in agitated reactors. The influence of several variables have been investigated. Once the best operating conditions had been selecting and an economic estimation had been done (with very really attractive results), the leaching stage has been designed for a plant of 30 tonnes per hour capacity. Cu extractions higher than 70% can be achieved with a residence time of only five hours. Despite of Cu(II) concentration in fed is as high as 30 g/l, bio oxidation stage can supply Fe(III) demanded by ferric leaching stage. (Author) 17 refs

  2. Experimental study on bio-leaching of high sulphuric acid consumption uranium ore by adding sulphide

    International Nuclear Information System (INIS)

    Meng Yunsheng; Zheng Ying; Liu Hui; Cheng Hao; Zhou Lei; Liu Chao; Fan Baotuan; Li Jianhua

    2012-01-01

    In order to decrease acid consumption and increase leaching rate, an experiment on bio-leach-ing of low grade uranium ore by adding sulphide was done. Compared with conventional leaching method, the leaching rate of uranium is improved by 3% and the leaching period was reduced to 60 days from 90 days by bio-leaching method of adding sulphide. In order to decrease acid consumption with bio-leaching by adding sulphide obviously, robust bacteria to sulphide should be chosen. (authors)

  3. Experiment on bio-leaching of associated molybdenum and uranium ore

    International Nuclear Information System (INIS)

    Zheng Ying; Fan Baotuan; Liu Jian; Meng Yunsheng; Liu Chao

    2007-01-01

    Column leaching experiment results on associated molybdenum uranium ore by bacteria (T. f) are introduced. The ore are leached for 210 days using bacteria domesticated to tolerate molybdenum, the leaching of uranium is of 98% and leaching of molybdenum is of 41%. Sulphuric acid produced by bio-oxidation of sulfides in ore can meet the demand of ore leaching. (authors)

  4. New technology of bio-heap leaching uranium ore and its industrial application in Ganzhou uranium mine

    International Nuclear Information System (INIS)

    Fan Baotuan; Meng Yunsheng; Liu Jian; Meng Jin; Li Weicai; Xiao Jinfeng; Chen Sencai; Du Yuhai; Huang Bin

    2006-10-01

    Bioleaching mechanism of uranium ore is discussed. Incubation and selection of new strain, biomembrane oxidizing tank--a kind of new equipment for bacteria culture and oxidation regeneration of leaching agent are also introduced. The results of industrial experiment and industrial production are summarized. Compared with conventional heap leaching, bioleaching period and acid amount are reduced, oxidant and leaching agent are saved, and uranium concentration in leaching solution is increased. It is the first time to realize industrial production by bio-heap leaching in Chinese uranium mine. New equipment-biomembrane oxidizing tank give the basis of bio-heap leaching industrial application. Bio-heap leaching process is an effective technique to reform technique of uranium mine and extract massive low-content uranium ore in China. (authors)

  5. Characterisation of Oyster Shell for Neutralisation of Bio- Leached ...

    African Journals Online (AJOL)

    Michael

    2016-12-02

    Dec 2, 2016 ... (Goodall et al., 2005; O'Connor and Dunne, 1994;. Kydros et al. ... while the gold is concentrated in the iron oxide (hemaetite) residue ..... leaching in the characterisation of complex gold ores” ... Australia, 413 pp. O'Connor ...

  6. Recovery of Metals and Stabilization of Arsenic from (Bio-)Leaching Operations by Engineered Biological Processes

    NARCIS (Netherlands)

    Gonzalez Contreras, P.A.; weghuis, M.O.; Weijma, J.; Buisman, C.J.N.

    2013-01-01

    This paper focuses on the application of biotechnological stabilization of arsenic from (bio-) leaching operations. One of the latest applications of the Thioteq technology is arsenic immobilization. The Thioteq-scorodite biorecovery reactor is an aerobic system to immobilise arsenic in

  7. The performance with data processing of chemical treatment with leaching and bio-leaching

    OpenAIRE

    Agron, Alili; Krstev, Boris; Krstev, Aleksandar; Stamenov, Goran

    2015-01-01

    The refractory or low grade lead/zinc domestic ores in Republic of Macedonia are investigated by conventional separation technology or flotation separation. In the meantime, investigations are directed to the new possibilities of leaching by microorganisms – bioleaching. The paper is result of these technologies and investigations carried out for recovery of in the mentioned ores. Using Simplex EVOP and computer program Multisimplex performances are appropriate and most acceptable and excel...

  8. The performance of leaching and bio-leaching from sulphide ores usiing SEVOP

    OpenAIRE

    Krstev, Boris; Krstev, Aleksandar; Golomeov, Blagoj; Golomeova, Mirjana; Sala, Ferat; Gocev, Zivko; Zivanovic, Jordan; Krstev, Dejan

    2013-01-01

    The refractory or low grade copper chalcopyrite ores or galena/sphalerite domestic ores in Republic of Macedonia are investigated by conventional copper flotation and selective flotation for galena/sphalerite. In the meantime, investigations are directed to the new possibilities of leaching by microorganisms – bioleaching. The paper is result of these technologies and investigations carried out for recovery of in the mentioned ores. Using Simplex EVOP and computer programme. Multisimple...

  9. The principles and examples of leaching and bio-leaching using SImplex EVOP

    OpenAIRE

    Krstev, Aleksandar; Krstev, Boris

    2014-01-01

    The refractory or low grade lead/zinc domestic ores in Republic of Macedonia are investigated by conventional separation technology or flotation separation. In the meantime, investigations are directed to the new possibilities of leaching by microorganisms - bioleaching. The paper is result of these technologies and investigations earned out for recovery of in the mentioned ores. Using Simples EVOP and computer program Multisimplex performances are appropriate and most acceptable and excellen...

  10. Using applicative software and software tools for the performance of leaching and bio-leaching

    OpenAIRE

    Krstev, Boris; Krstev, Aleksandar; Gocev, Zivko; Zdravev, Zoran; Krstev, Dejan; Zivanovic, Jordan

    2013-01-01

    The refractory or low grade lead/zinc domestic ores in Republic of Macedonia are investigated by conventional separation technology or flotation separation. In the mean time, investigations are directed to the new possibilities of leaching by microorganisms – bioleaching. The paper is result of these technologies and investigations carried out for recovery of in the mentioned ores. Using Simplex EVOP and computer program Multisimplex performances are appropriate and most acceptable and exce...

  11. The presentation of leaching and bio-leaching from different ores using SIMPLEX EVOP

    OpenAIRE

    Krstev, Boris; Krstev, Aleksandar; Golomeova, Mirjana; Gocev, Zivko

    2013-01-01

    The refractory or low grade lead/zinc domestic ores in Republic of Macedonia are investigated by conventional separation technology or flotation separation. In the mean time, investigations are directed to the new possibilities of leaching by microorganisms – bioleaching. The paper is result of these technologies and investigations carried out for recovery of in the mentioned ores. Using Simplex EVOP and computer program Multisimplex performances are appropriate and most acceptable and exce...

  12. The enhancing of Au-Ag-Te content in tellurium-bearing ore mineral by bio-oxidation-leaching

    Science.gov (United States)

    Kim, PyeongMan; Kim, HyunSoo; Myung, EunJi; Kim, YoonJung; Lee, YongBum; Park*, CheonYoung

    2015-04-01

    The purpose of this study is to enhance the content of valuable metals such as Au-Ag-Te in tellurium-bearing minerals by bio-oxidation-leaching. It was confirmed that pyrite, chalcopyrite, sphalerite and galena were produced together with tellurium-bearing minerals including hessite, sylvanite and tellurobismuthite from ore minerals and concentrates through microscopic observation and SEM/EDS analysis. In a bio-oxidation-leaching experiment, with regard to Au, Ag, Te, Cu and Fe, the changes in the amount of leaching and the content of leaching residues were compared and analyzed with each other depending on the adaptation of an indigenous microbe identified as Acidithiobacillus ferrooxidans. As a result of the experiment, the Au-Ag-Te content in tellurium-bearing ore mineral was enhanced in the order of physical oxidation leaching, physical/non-adaptive bio-oxidation-leaching and physical/adaptive biological leaching. It suggests that the bio-oxidation-leaching using microbes adapted in tellurium-bearing ore mineral can be used as a pre-treatment and a main process in a recovery process of valuable metals. "This research was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education(NRF-2013R1A1A2004898)"

  13. Nitrate leaching, direct and indirect nitrous oxide fluxes from sloping cropland in the purple soil area, southwestern China

    International Nuclear Information System (INIS)

    Zhou Minghua; Zhu Bo; Butterbach-Bahl, Klaus; Wang Tao; Bergmann, Jessica; Brüggemann, Nicolas; Wang Zhenhua; Li Taikui; Kuang Fuhong

    2012-01-01

    This study provides a combined dataset on N loss pathways and fluxes from sloping cropland in the purple soil area, southwestern China. A lysimeter experiment was conducted to quantify nitrate leaching (May 2004–May 2010) and N 2 O emission (May 2009–May 2010) losses. Nitrate leaching was the dominant N loss pathway and annual leaching fluxes ranged from 19.2 to 53.4 kg N ha −1 , with significant differences between individual observation years (P 2 O emissions due to N fertilizer use were 1.72 ± 0.34 kg N ha −1 yr −1 , which corresponds to an emission factor of 0.58 ± 0.12%. However, indirect N 2 O emissions caused by nitrate leaching and surface runoff N losses, may contribute another 0.15–0.42 kg N ha −1 yr −1 . Our study shows that nitrate leaching lowered direct N 2 O emissions, highlighting the importance for a better understanding of the tradeoff between direct and indirect N 2 O emissions for the development of meaningful N 2 O emission strategies. - Highlights: ► High NO 3 − leaching losses lowered direct N 2 O emissions. ► Hydrological N losses induced un-neglected indirect N 2 O emissions. ► Considering both direct and indirect N 2 O emission is needed for reduction strategies. - High nitrate leaching losses from sloping croplands of purple soil are accompanied with reductions in direct N 2 O emissions and stimulations of indirect N 2 O emissions.

  14. Metallurgical behavior of fine fractions of copper sulfide minerals in a combined process of modified flotation and agitated bio leaching

    International Nuclear Information System (INIS)

    Ibanez, J. P.; Ipinza, J.; Collao, N.; Ahlborn, G.

    2007-01-01

    The metallurgical behaviour of fine fraction of copper sulfide minerals of Compania Minera Quebrada Blanca S. A. was studied by concentration through flotation in aqueous media modified by alcohol followed by bio leaching of the concentrates. By using a 1% v/v of methanol, the metallurgical recovery of copper reaches 88%, while the iron recovery was 43%, the weight recovery was 18%, which indicates a high selectivity. these concentrates were then bio leached with and without nutrient medium, reaching 80% of copper recovery after 10 and 17 days, respectively. then, it is possible to conclude that this concentration-bio leaching metallurgical process is a promising route for copper recovery from the fine fraction of sulfide minerals. (Author) 24 refs

  15. Mechanical damage of a cement-based matrix subjected to a bio leaching test

    International Nuclear Information System (INIS)

    Lajili, H.; Grambin-Lapeyre, C.; Lajili, H.; Devillers, Ph.; Lajili, H.; Degorce-Dumas, J.R.; Roussy, J.; Bournazel, J.P.

    2007-01-01

    Waste packages are often embedded in concrete containers and placed in storage sites. Cement-based materials due to their favourable physical properties, are commonly used for the solidification and stabilisation of these wastes. Waste repositories can be situated in geological formations where microorganisms capable of degrading cement matrices are present. In such situations, the stability of concrete used in underground repositories for immobilization of nuclear waste may be impaired by Inter alia filamentous fungi. Fungal growth on cement matrices leads to physicochemical and mechanical degradations which considerably affects their durability, thus bio-leaching scenario must be seriously considered. This paper outlines the detrimental impact of Aspergillus niger fungus on the integrity of cement paste and describes the associated mechanisms of biodegradation. (authors)

  16. Bio-chemical remediation of under-ground water contaminated by uranium in-situ leaching

    International Nuclear Information System (INIS)

    Wang Qingliang; Li Qian; Zhang Hongcan; Hu Eming; Chen Yongbo

    2014-01-01

    In the process of uranium in-situ leaching, it was serious that strong acid, uranium and heavy metals, and SO_4"2"-, NO_3"- could contaminate underground water. To remedy these pollutants, conventional methods are high-cost and low-efficient, so a bio-chemical remediation method was proposed to cope with the under-ground water pollution in this study. The results showed, in the chemical treatment with Ca(OH)_2 neutralization, pH went up from 2.0 to 7.0, the removal rates of U, Mn"2"+, Zn"2"+, Pb"2"+, SO_4"2"-, NO_3"- were 91.5%, 78.3%, 85.1%, 100%, 71.4% and 2.6% respectively, SO_4"2"- and NO_3"- need to be treated again by bio-method. In the biological process, the Hydraulic Retention Time (HRT) of bioreactor was controlled at 42 h, and 100% NO_3"- and 70% SO_4"2"- in the contaminated water were removed; Acidithiobacillus ferrooxidans (A. f) liquid to H_2S showed better absorption effect, can fully meet the process requirements of H_2S removal. (authors)

  17. Investigation of aeration rate on Uranium bio leaching in internal airlift bioreactor

    International Nuclear Information System (INIS)

    Zolala, M. R.; Safdari, S. J.; Haghighi Asl, A.; Rashidi, A.

    2012-01-01

    Uranium is leached from the uranium ore of the second anomaly of Saghand by the Acidithiobacillus ferroxidans bacteria in an internal airlift bio-reactor. This study has been made to find the effect of aeration rate as well as its optimal value. The experiments have been carried out at 4 aeration rates to find the best recovery results in the least possible time duration. The results showed that the most percentage of the uranium recovery is in the superficial gas velocity of 0.010 m/s. The recovery at this aeration rate has an efficiency of more than 95 p ercent i n 11 days. Also, the best range for aeration study in the airlift bio-reactor is calculated with a minimum value of 0.0065 m/s which is the critical value of the uranium particle suspension as well as the maximum value of 0.015 m/s. The stress on the bacteria increases the recovery time process in velocities of more than 0.015 m/s.

  18. Bio leaching of Uranium - bearing material from Abu Thor area, West Central Sinai, Egypt for recovering uranium

    International Nuclear Information System (INIS)

    Abd El Wahab, G.M.; Amin, M.M.; Aita, S.K.

    2012-01-01

    A uranium-bearing material was recorded within the Intra-Carboniferous Paleokarst Profile of Um-Bogma Formation at Abu Thor area, West Central Sinai, Egypt. The present paper is concerned with the bio leaching of U and Cu using Aspergillus Niger (A. Niger) followed their proper recovery. The working Abu Thor representative sample assays 0.22% U as the element of interest as well as up to 25% CuO beside the other rock constituents SiO 2 (33%), Al 2 O 3 (10.4%) and CaO(8.5%). The effective bio leaching of U and Cu from Abu Thor ore sample using A.Niger was performed at the following optimum conditions: an incubation time of 6 days, sample/ liquid (S/L) ratio of 1/10, ph value of 1 and a temperature of 60 degree C. The prepared bio leach liquor assays 0.19 g/l of U and 15.8 g/l of Cu with leaching efficiencies of 97% and 79%, respectively. Uranium was recovered using 25% TBP in kerosene at O/A ratio of 1/1 and contact time of 5 min with achieved extraction efficiency of 96%. However the stripping of U was conducted by using 8% Na 2 CO 3 at A/O ratio of 1/1 and contact time of 5 min with stripping efficiency reached 99%. On the other hand, Cu was directly precipitated as CuS using the freshly released H 2 S gas with the addition of solid Na 2 S. The optimum precipitation conditions were S/L ratio of 1/100, ph 1.5 and room temperature where the precipitation efficiency of Cu achieved 99%

  19. Data-Foraging-Oriented Reconnaissance Based on Bio-Inspired Indirect Communication for Aerial Vehicles

    Directory of Open Access Journals (Sweden)

    Josué Castañeda Cisneros

    2017-07-01

    Full Text Available In recent years, aerial vehicles have allowed exploring scenarios with harsh conditions. These can conduct reconnaissance tasks in areas that change periodically and have a high spatial and temporal resolution. The objective of a reconnaissance task is to survey an area and retrieve strategic information. The aerial vehicles, however, have inherent constraints in terms of energy and transmission range due to their mobility. Despite these constraints, the Data Foraging problem requires the aerial vehicles to exchange information about profitable data sources. In Data Foraging, establishing a single path is not viable because of dynamic conditions of the environment. Thus, reconnaissance must be focused on periodically searching profitable environmental data sources, as some animals perform foraging. In this work, a data-foraging-oriented reconnaissance algorithm based on bio-inspired indirect communication for aerial vehicles is presented. The approach establishes several paths that overlap to identify valuable data sources. Inspired by the stigmergy principle, the aerial vehicles indirectly communicate through artificial pheromones. The aerial vehicles traverse the environment using a heuristic algorithm that uses the artificial pheromones as feedback. The solution is formally defined and mathematically evaluated. In addition, we show the viability of the algorithm by simulations which have been tested through various statistical hypothesis.

  20. Comparison of the extraction efficiencies of different leaching agents for reliable assessment of bio-accessible trace metal fractions in airborne particulate matter

    Directory of Open Access Journals (Sweden)

    Mukhtar A.

    2013-04-01

    Full Text Available In present study, an in-vitro physiologically based extraction test has been applied for extraction of bio-accessible trace metal fractions in airborne particulate matter (APM samples collected from different urban sites in Austria and Pakistan using the leaching agents H2O, sodium chloride, ammonium acetate, ammonium citrate, synthetic gastric juice and artificial lung fluids. Obtained extracts were then measured using an ETV-ICP-OES procedure which allowed highly sensitive measurement of dissolved analytes even in the presence of leaching agents. Derived results indicated that the investigated leaching agents extract different amounts of trace metals. In general, leaching agents with organic nature yielded comparatively greater extractable and thus bio-accessible trace metal fractions to that of simple solvents like H2O or aqueous NaCl solution. With water, only 26.3±4.0% of Cd was found to be bio-accessible whereas 88.4±24.8 of Cd was obtained as bio-accessible fraction with the use of synthetic gastric juice. The concentrations of bio-accessible metal fractions varied from 0.4 ng m−3 (Cd to 714 ng m−3 (Zn and 0.3 ng m−3 (Cd to 190 ng m−3 (Zn for PM10 samples collected from Karachi (Pakistan and Graz (Austria respectively.

  1. Fabrication of channeled scaffolds with ordered array of micro-pores through microsphere leaching and indirect Rapid Prototyping technique.

    Science.gov (United States)

    Tan, J Y; Chua, C K; Leong, K F

    2013-02-01

    Advanced scaffold fabrication techniques such as Rapid Prototyping (RP) are generally recognized to be advantageous over conventional fabrication methods in terms architectural control and reproducibility. Yet, most RP techniques tend to suffer from resolution limitations which result in scaffolds with uncontrollable, random-size pores and low porosity, albeit having interconnected channels which is characteristically present in most RP scaffolds. With the increasing number of studies demonstrating the profound influences of scaffold pore architecture on cell behavior and overall tissue growth, a scaffold fabrication method with sufficient architectural control becomes imperative. The present study demonstrates the use of RP fabrication techniques to create scaffolds having interconnected channels as well as controllable micro-size pores. Adopted from the concepts of porogen leaching and indirect RP techniques, the proposed fabrication method uses monodisperse microspheres to create an ordered, hexagonal closed packed (HCP) array of micro-pores that surrounds the existing channels of the RP scaffold. The pore structure of the scaffold is shaped using a single sacrificial construct which comprises the microspheres and a dissolvable RP mold that were sintered together. As such, the size of pores as well as the channel configuration of the scaffold can be tailored based on the design of the RP mold and the size of microspheres used. The fabrication method developed in this work can be a promising alternative way of preparing scaffolds with customized pore structures that may be required for specific studies concerning cell-scaffold interactions.

  2. Bio- and mineral acid leaching of rare earth elements from synthetic phosphogypsum

    Science.gov (United States)

    Hu, Z.; Antonick, P.; Fujita, Y.; Reed, D. W.; Riman, R.; Eslamimanesh, A.; Das, G.; Anderko, A.; Wu, L.; Shivaramaiah, R.; Navrotsky, A.

    2017-12-01

    Rare earth elements (REE) are critical to many clean energy technologies. However, the lack of U.S. domestic production and the reliance on imported REE put U.S. energy security at risk. Consequently development of new sources is of strategic interest. Global phosphate deposits contain 27 million tons of REE and 38% of these REE end up in phosphogypsum (PG) waste during phosphate fertilizer production. Recovering REE from PG is a first step toward a trash-to-treasure transformation. We studied the leaching of REE from synthetic PG samples containing Y, Nd, or Eu using a suite of lixiviants including spent medium from the growth of the bacterium Gluconobacter oxydans ("biolixiviant"), gluconic acid, common mineral acids (phosphoric and sulfuric), and water. Synthetic PG was used to facilitate the comparison of the different lixiviants; real PG waste is extremely heterogeneous. Gluconic acid was the predominant identified organic acid in the biolixiviant. The leaching efficiency of the acidic lixiviants at the same pH (2.1) or molar concentration as gluconic acid in the biolixiviant (220 mM) were compared and rationalized by thermodynamic simulation using the mixed-solvent electrolyte model. Initial results indicate that the biolixiviant was more effective at leaching the REE than the mineral acids at pH 2.1. At 220 mM acid concentrations, sulfuric acid was the most effective, followed by the biolixiviant. Interestingly, for a given lixiviant, the leaching behavior of the REE differed. This study provides insight into the definition of an efficient lixiviant for leaching REE from phosphate fertilizer production waste.

  3. Particle Size Effects in Bio leaching of Uranium From Saghand Ore by Acidithiobacillus Ferroxidans (A.f.)

    International Nuclear Information System (INIS)

    Rashidi, A.; Roosta Azad, R.; Safdari, S. J.

    2012-01-01

    The effect of mineral particle size on the bio leaching of uranium from Saghand mine (anomaly 1 and 2) by acidophilic mesophile Acidithiobacillus ferroxidans was investigated in a shake flask. The findings are indicating that this strain is suitable for the uranium recovery from the mentioned ore. In the range of our studies the uranium recovery is faster in the case of d 80 =108 micron from anomaly 1, while, a comminution level of d 80 =160 micron was obtained as an appropriate size for the anomaly 2. The results showed that the particle size distribution of the mineral in this range did not considerably influence the microbial activity. Also, based on the results of bacterial oxidation, the negative effects and toxicity due to the presence of solid and solute components do not put a limit on the microbial activity, and at the tested parameters range, the grown microbial population is performing the desired process excellently.

  4. Fabrication and evaluation of porous Ti–HA bio-nanomaterial by leaching process

    Directory of Open Access Journals (Sweden)

    A.M. Omran

    2015-05-01

    Full Text Available A porous surface of Ti–HA composite was successfully fabricated by pulsed current activated sintering (PCAS, followed by leaching using diluted H3PO4. The Ti and HA powders were mixed at different contents of the HA, Ti-5, 10, 30 and 40 wt% HA powders. The mixed powders were pressed in a coated graphite die using pulsed current activated sintering (PCAS under pressure of 60 MPa at temperature of 1000 °C for 5 min. The sintered Ti–HA specimens were immersed in the eight kinds of leaching solutions at room temperature for 24 h. The leached specimen’s surfaces were characterized using XRD, SEM, EDX and Rockwell hardness. The XRD patterns after sintering show that many phases were detected at the sintered specimen surfaces such as; Ti2O, CaO, CaTiO3, TixPy in addition to the remaining Ti and HA. Furthermore, the high concentration H3PO4 leaching solution is more efficient than the low concentration. Also the produced porous surfaces of Ti–HA materials containing more than 30% HA have a low relative density and hardness than the commercial Ti–6Al–4V ELI alloy. In a word, the presence of porous surface coated by HA will promote the nucleation of the biological apatite created with the human tissue and increase the bonding between them. So, the produced porous materials are considered so easy for the muscle cells to permeate after transplanted with high coherence.

  5. Comparison of the extraction efficiencies of different leaching agents for reliable assessment of bio-accessible trace metal fractions in airborne particulate matter

    OpenAIRE

    Mukhtar A.; Limbeck A.

    2013-01-01

    In present study, an in-vitro physiologically based extraction test has been applied for extraction of bio-accessible trace metal fractions in airborne particulate matter (APM) samples collected from different urban sites in Austria and Pakistan using the leaching agents H2O, sodium chloride, ammonium acetate, ammonium citrate, synthetic gastric juice and artificial lung fluids. Obtained extracts were then measured using an ETV-ICP-OES procedure which allowed highly sensitive measurement of d...

  6. Optimization of Different Physical Parameters For Bio leaching of Uranium and Rare Earth Elements From Nubia Sandstones, Wadi Natash, Eastern Desert, Egypt

    International Nuclear Information System (INIS)

    Ibrahim, H.E.; Mira, H.I.; Amin, M.M.; MORSY, W.M.; Abdel Aziz, Z.K.

    2013-01-01

    Five fungal species were isolated from two Nubia sandstone samples at Wadi Natash, Eastern Desert, These species were then tested for their ability in bio leaching of uranium and rare earth elements he two ore samples (G1 and G2) whose assay of U attains 65 and 150 ppm respectively while their assay Es attains 1590 and 1152 ppm respectively. Among the isolated fungi both Aspergillus niger and Aspergillus flavus have been the only species that give the highest leaching efficiencies .Thus in case of G2 sample the leaching of U has reached up to 90% of uranium by using A. niger while that of REEs has attained 84% by A flavus under the studied optimum conditions .The latter involved shaking at 100 rpm for 7 days incubation time, 2% pulp density,> 0.2 mm grain size and 35°C incubation temperature. Production of organic acids (oxalic and, citric acids) by two fungal species in their culture filtrate represents the key realized bio leaching processes

  7. The effect of cooking and washing rice on the bio-accessibility of As, Cu, Fe, V and Zn using an on-line continuous leaching method.

    Science.gov (United States)

    Horner, Nolan S; Beauchemin, Diane

    2013-01-03

    A previously developed method based on continuous on-line leaching with artificial gastro-intestinal fluids was used to determine the bio-accessible fraction of As, Cu, Fe, V and Zn in brown and white rice from California by inductively coupled mass spectrometry (ICP-MS). Saliva generally accounted for the largest percentage of total element leached in comparison to gastric and intestinal juices. Arsenic speciation analysis was performed on the saliva and gastric juice leachates using ion exchange chromatography coupled to ICP-MS. The four most toxic species of As (As(III), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA) and As(V)), as well as Cl(-) in the gastric juice leachate, were successfully separated within 5.5min using a simple nitric acid gradient. While cooking rice had relatively little effect on total bio-accessibility, a change in species from As(V) and DMA to As(III) was observed for both types of rice. On the other hand, washing the rice with doubly deionized water prior to cooking removed a large percentage of the total bio-accessible fraction of As, Cu, Fe, V and Zn. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Standardization of a sulfur quantitative analysis method by X ray fluorescence in a leaching solution for bio-available sulfates in soil

    International Nuclear Information System (INIS)

    Morales S, E.; Aguilar S, E.

    1989-11-01

    A method for bio-available sulfate analysis in soils is described. A Ca(H2PO4) leaching solution was used for soil samples treatment. A standard NaSO4 solution was used for preparing a calibration curve and also the fundamental parameters method approach was employed. An Am-241 (100 mCi) source and a Si-Li detector were employed. Analysis could be done in 5 minutes; good reproducibility, 5 and accuracy, 5 were obtained. The method is very competitive with conventional nephelometry where good and reproducible suspensions are difficult to obtain. (author)

  9. Metallurgical behavior of fine fractions of copper sulfide minerals in a combined process of modified flotation and agitated bio leaching; Respuesta metalurgica de fracciones finas de minerales sulfurados de cobre en un proceso combinado de flotacion modificada y biolixiviacion agitada

    Energy Technology Data Exchange (ETDEWEB)

    Ibanez, J. P.; Ipinza, J.; Collao, N.; Ahlborn, G.

    2007-07-01

    The metallurgical behaviour of fine fraction of copper sulfide minerals of Compania Minera Quebrada Blanca S. A. was studied by concentration through flotation in aqueous media modified by alcohol followed by bio leaching of the concentrates. By using a 1% v/v of methanol, the metallurgical recovery of copper reaches 88%, while the iron recovery was 43%, the weight recovery was 18%, which indicates a high selectivity. these concentrates were then bio leached with and without nutrient medium, reaching 80% of copper recovery after 10 and 17 days, respectively. then, it is possible to conclude that this concentration-bio leaching metallurgical process is a promising route for copper recovery from the fine fraction of sulfide minerals. (Author) 24 refs.

  10. Performance analysis of a bio-gasification based combined cycle power plant employing indirectly heated humid air turbine

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, S., E-mail: sankha.deepp@gmail.com; Mondal, P., E-mail: mondal.pradip87@gmail.com; Ghosh, S., E-mail: sudipghosh.becollege@gmail.com [Department of Mechanical Engineering, Indian Institute of Engineering Science and Technology, Shibpur, Howrah – 711103, West Bengal (India)

    2016-07-12

    Rapid depletion of fossil fuel has forced mankind to look into alternative fuel resources. In this context, biomass based power generation employing gas turbine appears to be a popular choice. Bio-gasification based combined cycle provides a feasible solution as far as grid-independent power generation is concerned for rural electrification projects. Indirectly heated gas turbine cycles are promising alternatives as they avoid downstream gas cleaning systems. Advanced thermodynamic cycles have become an interesting area of study to improve plant efficiency. Water injected system is one of the most attractive options in this field of applications. This paper presents a theoretical model of a biomass gasification based combined cycle that employs an indirectly heated humid air turbine (HAT) in the topping cycle. Maximum overall electrical efficiency is found to be around 41%. Gas turbine specific air consumption by mass is minimum when pressure ratio is 6. The study reveals that, incorporation of the humidification process helps to improve the overall performance of the plant.

  11. A simple method using on-line continuous leaching and ion exchange chromatography coupled to inductively coupled plasma mass spectrometry for the speciation analysis of bio-accessible arsenic in rice.

    Science.gov (United States)

    Horner, Nolan S; Beauchemin, Diane

    2012-03-02

    A simple method for the speciation analysis of bio-accessible arsenic (As) in rice was developed using a continuous on-line leaching method to release the bio-accessible fraction. The continuous on-line leaching method has several advantages over commonly used batch methods including quicker and easier sample preparation, reduced risk of contamination and access to real time leaching data. The bio-accessibility of As in the samples was monitored using inductively coupled plasma mass spectrometry (ICP-MS). Results from a certified reference material as well as cooked and uncooked white rice showed that the majority of As was leached by saliva. Results obtained using the continuous on-line leaching method were comparable to those obtained using a batch method. Speciation analysis of the saliva leachate was performed using ion exchange chromatography coupled to ICP-MS. The four most toxic forms of As (As(III), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA) and As(V)) were clearly separated within 5 min in a single chromatographic run. Over 92% of bio-accessible As in the certified reference material and uncooked white rice sample was in the form of DMA and As(V), whereas it was present as DMA and As(III) in the cooked white rice. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Mechanical damage of a cement-based matrix subjected to a bio leaching test; Endommagement d'une matrice cimentaire soumise a un essai couple de biolixiviation

    Energy Technology Data Exchange (ETDEWEB)

    Lajili, H.; Grambin-Lapeyre, C. [Centre de Geosciences, Ecole des Mines de Paris, 77 - Marne la Vallee (France); Lajili, H.; Devillers, Ph. [Centre des Materiaux de Grande Diffusion, Ecole des Mines d' Ales, 30 - Ales (France); Lajili, H.; Degorce-Dumas, J.R.; Roussy, J. [Laboratoire Genie de l' Environnement Industriel, Ecole des Mines d' Ales, 30 - Ales (France); Bournazel, J.P. [14 rue Rene Cassin, 13 - Arles (France)

    2007-07-01

    Waste packages are often embedded in concrete containers and placed in storage sites. Cement-based materials due to their favourable physical properties, are commonly used for the solidification and stabilisation of these wastes. Waste repositories can be situated in geological formations where microorganisms capable of degrading cement matrices are present. In such situations, the stability of concrete used in underground repositories for immobilization of nuclear waste may be impaired by Inter alia filamentous fungi. Fungal growth on cement matrices leads to physicochemical and mechanical degradations which considerably affects their durability, thus bio-leaching scenario must be seriously considered. This paper outlines the detrimental impact of Aspergillus niger fungus on the integrity of cement paste and describes the associated mechanisms of biodegradation. (authors)

  13. Preparation of porous bio-char and activated carbon from rice husk by leaching ash and chemical activation.

    Science.gov (United States)

    Ahiduzzaman, Md; Sadrul Islam, A K M

    2016-01-01

    Preparation porous bio-char and activated carbon from rice husk char study has been conducted in this study. Rice husk char contains high amount silica that retards the porousness of bio-char. Porousness of rice husk char could be enhanced by removing the silica from char and applying heat at high temperature. Furthermore, the char is activated by using chemical activation under high temperature. In this study no inert media is used. The study is conducted at low oxygen environment by applying biomass for consuming oxygen inside reactor and double crucible method (one crucible inside another) is applied to prevent intrusion of oxygen into the char. The study results shows that porous carbon is prepared successfully without using any inert media. The adsorption capacity of material increased due to removal of silica and due to the activation with zinc chloride compared to using raw rice husk char. The surface area of porous carbon and activated carbon are found to be 28, 331 and 645 m(2) g(-1) for raw rice husk char, silica removed rice husk char and zinc chloride activated rice husk char, respectively. It is concluded from this study that porous bio-char and activated carbon could be prepared in normal environmental conditions instead of inert media. This study shows a method and possibility of activated carbon from agro-waste, and it could be scaled up for commercial production.

  14. Biosynthesis of nano cupric oxide on cotton using Seidlitzia rosmarinus ashes utilizing bio, photo, acid sensing and leaching properties.

    Science.gov (United States)

    Bashiri Rezaie, Ali; Montazer, Majid; Rad, Mahnaz Mahmoudi

    2017-12-01

    In this research, a facile, rapid and eco-friendly method is introduced for synthesis and loading of cupric oxide on cellulosic chains of cotton fabric with functional properties. Seidlitzia rosmarinus ashes and copper acetate were employed as a natural source of alkaline and metal salt without further chemical materials. The treated samples indicated very good antibacterial activities toward both pathogen Staphylococcus aureus as Gram-positive and Escherichia coli as Gram-negative bacteria. Significant self-cleaning properties against degradation of methylene blue stain under UV irradiation were found. The sensing properties of high concentrated inorganic and organic acids such as sulfuric and formic acids based on colorimetric alterations of the treated fabrics were also confirmed showing acid leaching effects of the treated fabrics. Further, the treated samples showed coloring effects with an enhancement on the physio-mechanical properties including tensile strength, crease recovery angle and hydrophobocity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Estimation of the bio-accessible fraction of Cr, As, Cd and Pb in locally available bread using on-line continuous leaching method coupled to inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Lamsal, Ram P; Beauchemin, Diane

    2015-03-31

    A previously developed, efficient and simple on-line leaching method was used to assess the maximum bio-accessible fraction (assuming no synergistic effect from other food and beverage) of potentially toxic elements (Cr, As, Cd and Pb) in whole wheat brown and white bread samples. Artificial saliva, gastric juice and intestinal juice were successively pumped into a mini-column, packed with bread (maintained at 37 °C) connected on-line to the nebulizer of an inductively coupled plasma mass spectrometry (ICP-MS) instrument equipped with a collision-reaction interface (CRI) using hydrogen as reaction gas to minimize carbon- and chlorine-based polyatomic interferences. In contrast to the conventional batch method to which it was compared, this approach provides real-time monitoring of potentially toxic elements that are continuously released during leaching. Mass balance for both methods was verified at the 95% confidence level. Results obtained from the whole wheat brown and white bread showed that the majority of Cr, Cd and Pb was leached by gastric juice but, in contrast, the majority of As was leached by saliva. While there was higher total content for elements in whole wheat bread than in white bread, a higher percentage of elements were bio-accessible in white bread than in whole wheat bread. Both the on-line and batch methods indicate that 40-98% of toxic elements in bread samples are bio-accessible. While comparison of total analyte concentrations with provisional tolerable daily intake values may indicate some serious health concern for children, when accounting for the bio-accessibility of these elements, bread consumption is found to be safe for all ages. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Application of microorganism to in-situ leaching mining

    International Nuclear Information System (INIS)

    Yu, Runlan; Sato, Kazuhiko; Nagara, Shuichi; Yamana, Satoshi

    1998-01-01

    In-situ leaching (ISL) technique has come into the spotlight recently because of its low production costs and low environmental impact. In China, development and application of economical ISL techniques are also being studied. To design a pilot scale ISL 'bioreactor' in China, applicability of microorganisms to ISL mining was evaluated at Ningyo Toge Works as a part of Scientist Exchange Program of the Science and Technology Agency. An overview of the indirect bio-ISL method with iron oxidizing bacteria, Thiobacillus ferroxidans (TF), and results from experiment to determine factors for the ISL 'bioreactor' are discussed. (author)

  17. Bacterial Leaching

    Indian Academy of Sciences (India)

    and studies microbial biotechnology and ... foundation for subsequent research into the role of microorgan- ... are more readily accesible, for example those in solution, rather .... Vat leaching as currently applied to oxide ores involves the.

  18. Leaching mechanisms

    International Nuclear Information System (INIS)

    Dougherty, D.R.; Colombo, P.

    1984-01-01

    Sufficient data are lacking to provide a basis for adequately assessing the long term leaching behavior of solidified low level radioactive waste forms in their disposal environment. Although the release of radioactivity from a waste form to an aqueous environment is recognized to be due to one or more mechanisms such as diffusion, dissolution, corrosion or ion exchange, the leaching mechanisms and the factors which control the leaching behavior of waste forms are not fully understood. This study will determine the prevailing mechanisms for a variety of selected LLW solidification agents which are being considered for use by defense and commercial generators and which will cover the broadest possible number of mechanisms. The investigation will proceed by the postulation of mathematical models representative of the prevailing mechanism(s) and the use of statistically designed experiments to test the actual leaching behavior of laborattory samples against the postulated representations. Maximum use of existing leach data in the literature will be made by incorporating literature results into a computerized data base along with the experimental results generated in this task

  19. Leaching process

    International Nuclear Information System (INIS)

    Heinen, H.J.; McClelland, G.E.; Lindstrom, R.E.

    1982-01-01

    A gold and uranium ore is heap leached in accordance with the process comprising initial agglomeration of fines in the feed by means of a binding agent and cyanide solution. The lixiviant comprises a compatible mixture of sodium cyanide and sodium bicarbonate

  20. Leaching process

    Energy Technology Data Exchange (ETDEWEB)

    Heinen, H J; McClelland, G E; Lindstrom, R E

    1982-10-18

    A gold and uranium ore is heap leached in accordance with the process comprising initial agglomeration of fines in the feed by means of a binding agent and cyanide solution. The lixiviant comprises a compatible mixture of sodium cyanide and sodium bicarbonate.

  1. Gas anti-solvent precipitation assisted salt leaching for generation of micro- and nano-porous wall in bio-polymeric 3D scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Flaibani, Marina; Elvassore, Nicola, E-mail: nicola.elvassore@unipd.it

    2012-08-01

    The mass transport through biocompatible and biodegradable polymeric 3D porous scaffolds may be depleted by non-porous impermeable internal walls. As consequence the concentration of metabolites and growth factors within the scaffold may be heterogeneous leading to different cell fate depending on spatial cell location, and in some cases it may compromise cell survival. In this work, we fabricated polymeric scaffolds with micro- and nano-scale porosity by developing a new technique that couples two conventional scaffold production methods: solvent casting-salt leaching and gas antisolvent precipitation. 10-15 w/w solutions of a hyaluronic benzyl esters (HYAFF11) and poly-(lactic acid) (PLA) were used to fill packed beds of 0.177-0.425 mm NaCl crystals. The polymer precipitation in micro and nano-porous structures between the salt crystals was induced by high-pressure gas, then its flushing extracted the residual solvent. The salt was removed by water-wash. Morphological analysis by scanning electron microscopy showed a uniform porosity ({approx} 70%) and a high interconnectivity between porous. The polymeric walls were porous themselves counting for 30% of the total porosity. This wall porosity did not lead to a remarkable change in compressive modulus, deformation, and rupture pressure. Scaffold biocompatibility was tested with murine muscle cell line C2C12 for 4 and 7 days. Viability analysis and histology showed that micro- and nano-porous scaffolds are biocompatible and suitable for 3D cell culture promoting cell adhesion on the polymeric wall and allowing their proliferation in layers. Micro- and nano-scale porosities enhance cell migration and growth in the inner part of the scaffold. - Highlights: Black-Right-Pointing-Pointer Gas anti-solvent precipitation and salt leaching for scaffold fabrication. Black-Right-Pointing-Pointer Hyaluronic benzyl esters (HYAFF11) and poly-(lactic acid) (PLA) sponges. Black-Right-Pointing-Pointer Gas anti-solvent precipitation

  2. Gas anti-solvent precipitation assisted salt leaching for generation of micro- and nano-porous wall in bio-polymeric 3D scaffolds

    International Nuclear Information System (INIS)

    Flaibani, Marina; Elvassore, Nicola

    2012-01-01

    The mass transport through biocompatible and biodegradable polymeric 3D porous scaffolds may be depleted by non-porous impermeable internal walls. As consequence the concentration of metabolites and growth factors within the scaffold may be heterogeneous leading to different cell fate depending on spatial cell location, and in some cases it may compromise cell survival. In this work, we fabricated polymeric scaffolds with micro- and nano-scale porosity by developing a new technique that couples two conventional scaffold production methods: solvent casting-salt leaching and gas antisolvent precipitation. 10–15 w/w solutions of a hyaluronic benzyl esters (HYAFF11) and poly-(lactic acid) (PLA) were used to fill packed beds of 0.177–0.425 mm NaCl crystals. The polymer precipitation in micro and nano-porous structures between the salt crystals was induced by high-pressure gas, then its flushing extracted the residual solvent. The salt was removed by water-wash. Morphological analysis by scanning electron microscopy showed a uniform porosity (∼ 70%) and a high interconnectivity between porous. The polymeric walls were porous themselves counting for 30% of the total porosity. This wall porosity did not lead to a remarkable change in compressive modulus, deformation, and rupture pressure. Scaffold biocompatibility was tested with murine muscle cell line C2C12 for 4 and 7 days. Viability analysis and histology showed that micro- and nano-porous scaffolds are biocompatible and suitable for 3D cell culture promoting cell adhesion on the polymeric wall and allowing their proliferation in layers. Micro- and nano-scale porosities enhance cell migration and growth in the inner part of the scaffold. - Highlights: ► Gas anti-solvent precipitation and salt leaching for scaffold fabrication. ► Hyaluronic benzyl esters (HYAFF11) and poly-(lactic acid) (PLA) sponges. ► Gas anti-solvent precipitation induces nano-porous structures. ► Scaffolds are biocompatible and

  3. Gas anti-solvent precipitation assisted salt leaching for generation of micro- and nano-porous wall in bio-polymeric 3D scaffolds.

    Science.gov (United States)

    Flaibani, Marina; Elvassore, Nicola

    2012-08-01

    The mass transport through biocompatible and biodegradable polymeric 3D porous scaffolds may be depleted by non-porous impermeable internal walls. As consequence the concentration of metabolites and growth factors within the scaffold may be heterogeneous leading to different cell fate depending on spatial cell location, and in some cases it may compromise cell survival. In this work, we fabricated polymeric scaffolds with micro- and nano-scale porosity by developing a new technique that couples two conventional scaffold production methods: solvent casting-salt leaching and gas antisolvent precipitation. 10-15 w/w solutions of a hyaluronic benzyl esters (HYAFF11) and poly-(lactic acid) (PLA) were used to fill packed beds of 0.177-0.425 mm NaCl crystals. The polymer precipitation in micro and nano-porous structures between the salt crystals was induced by high-pressure gas, then its flushing extracted the residual solvent. The salt was removed by water-wash. Morphological analysis by scanning electron microscopy showed a uniform porosity (~70%) and a high interconnectivity between porous. The polymeric walls were porous themselves counting for 30% of the total porosity. This wall porosity did not lead to a remarkable change in compressive modulus, deformation, and rupture pressure. Scaffold biocompatibility was tested with murine muscle cell line C2C12 for 4 and 7 days. Viability analysis and histology showed that micro- and nano-porous scaffolds are biocompatible and suitable for 3D cell culture promoting cell adhesion on the polymeric wall and allowing their proliferation in layers. Micro- and nano-scale porosities enhance cell migration and growth in the inner part of the scaffold. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Heap leaching for uranium

    International Nuclear Information System (INIS)

    1988-01-01

    Denison Mines Ltd. is using two bacterial leaching processes to combat the high cost of extracting uranium from low grade ore in thin reefs. Both processes use thiobacillus ferro-oxidans, a bacterium that employs the oxidation of ferrous iron and sulphur as its source of energy for growth. The first method is flood leaching, in which ore is subjected to successive flood, drain and rest cycles. The second, trickle leaching, uses sprinklers to douse the broken muck continuously with leaching solution. In areas where grades are too low to justify the expense of hauling the ore to the surface, the company is using this biological process underground to recover uranium. In 1987 Denison recovered 840 000 lb of uranium through bacterial heap leaching. It plans to have biological in-place leaching contribute 25% of the total uranium production by 1990. (fig.)

  5. Nitrate Leaching Management

    Science.gov (United States)

    Nitrate (NO3) leaching is a significant nitrogen (N) loss process for agriculture that must be managed to minimize NO3 enrichment of groundwater and surface waters. Managing NO3 leaching should involve the application of basic principles of understanding the site’s hydrologic cycle, avoiding excess ...

  6. Nitrate leaching index

    Science.gov (United States)

    The Nitrate Leaching Index is a rapid assessment tool that evaluates nitrate (NO3) leaching potential based on basic soil and climate information. It is the basis for many nutrient management planning efforts, but it has considerable limitations because of : 1) an oversimplification of the processes...

  7. Immobilized waste leaching

    International Nuclear Information System (INIS)

    Suarez, A.A.

    1989-01-01

    The main mechanism by which the immobilized radioactive materials can return to biosphere is the leaching due to the intrusion of water into the repositories. Some mathematical models and experiments utilized to evaluate the leaching rates in different immobilization matrices are described. (author) [pt

  8. In situ leaching of uranium

    International Nuclear Information System (INIS)

    Martin, B.

    1980-01-01

    A process is described for the in-situ leaching of uranium-containing ores employing an acidic leach liquor containing peroxymonosulphuric acid. Preferably, additionally, sulphuric acid is present in the leach liquor. (author)

  9. Chlorination leaching of cadmium

    International Nuclear Information System (INIS)

    Lach, E.; Pajak, I.; Bojanowska, A.

    1978-01-01

    The results of the investigations on chlorination leaching of cadmium from dust coming from dry dust collector of sinter belt, that is leaching with water saturated with gaseous chlorine and leaching with solutions of ammonium chloride and sodium chloride were given. The optimum conditions for these processes were established. It was found, that the method of leaching in the presence of gaseous chlorine is more effective, as it allows to report into the solution over 90% cadmium contained in dust. Owing to technical difficulties, environmental protection and safety conditions more advantageous seems to be the use as leaching agent of the ammonium chloride solutions. When applying 20% NH 4 Cl and temperature of 60 0 C, the time of 2 hours and the ratio of solid to liquid of 1:5, 70% cadmium contained in the dust can be reported into the solution. (auth.)

  10. Detoxification of mercury pollutant leached from spent fluorescent lamps using bacterial strains.

    Science.gov (United States)

    Al-Ghouti, Mohammad A; Abuqaoud, Reem H; Abu-Dieyeh, Mohammed H

    2016-03-01

    The spent fluorescent lamps (SFLs) are being classified as a hazardous waste due to having mercury as one of its main components. Mercury is considered the second most toxic heavy metal (arsenic is the first) with harmful effects on animal nervous system as it causes different neurological disorders. In this research, the mercury from phosphor powder was leached, then bioremediated using bacterial strains isolated from Qatari environment. Leaching of mercury was carried out with nitric and hydrochloric acid solutions using two approaches: leaching at ambient conditions and microwave-assisted leaching. The results obtained from this research showed that microwave-assisted leaching method was significantly better in leaching mercury than the acid leaching where the mercury leaching efficiency reached 76.4%. For mercury bio-uptake, twenty bacterial strains (previously isolated and purified from petroleum oil contaminated soils) were sub-cultured on Luria Bertani (LB) plates with mercury chloride to check the bacterial tolerance to mercury. Seven of these twenty strains showed a degree of tolerance to mercury. The bio-uptake capacities of the promising strains were investigated using the mercury leached from the fluorescent lamps. Three of the strains (Enterobacter helveticus, Citrobacter amalonaticus, and Cronobacter muytjensii) showed bio-uptake efficiency ranged from 28.8% to 63.6%. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Bicarbonate leaching of uranium

    International Nuclear Information System (INIS)

    Mason, C.

    1998-01-01

    The alkaline leach process for extracting uranium from uranium ores is reviewed. This process is dependent on the chemistry of uranium and so is independent on the type of mining system (conventional, heap or in-situ) used. Particular reference is made to the geochemical conditions at Crownpoint. Some supporting data from studies using alkaline leach for remediation of uranium-contaminated sites is presented

  12. Bicarbonate leaching of uranium

    Energy Technology Data Exchange (ETDEWEB)

    Mason, C.

    1998-12-31

    The alkaline leach process for extracting uranium from uranium ores is reviewed. This process is dependent on the chemistry of uranium and so is independent on the type of mining system (conventional, heap or in-situ) used. Particular reference is made to the geochemical conditions at Crownpoint. Some supporting data from studies using alkaline leach for remediation of uranium-contaminated sites is presented.

  13. Glass leaching performance

    International Nuclear Information System (INIS)

    Chick, L.A.; Turcotte, R.P.

    1983-05-01

    Current understanding of the leaching performance of high-level nuclear waste (HLW) glass is summarized. The empirical model of waste glass leaching behavior developed shows that at high water flow rates the glass leach rate is kinetically limited to a maximum value. At intermediate water flow rates, leaching is limited by the solution concentration of silica and decreases with decreasing water flow rates. Release of soluble elements is controlled by silica dissolution because silica forms the binding network of the glass. At low water flow rates, mass loss rates reach values controlled by formation rates of alteration minerals, or by diffusion of dissolution products through essentially stagnant water. The parameters reviewed with respect to their quantifiable influence on leaching behavior include temperature, pH, leachant composition, glass composition, thermal history, and radiation. Of these, temperature is most important since the rate of mass loss approximately doubles with each 10 0 C increase in dilute solutions. The pH has small effects within the 4 to 10 range. The chemical composition of the leachant is most important with regard to its influence on alteration product formation. Glass composition exhibits the largest effects at high flow rates where improved glasses leach from ten to thirty times slower than glass 76 to 68. The effects of the thermal history (devitrification) of the glass are not likely to be significant. Radiation effects are important primarily in that radiolysis can potentially drive pH values to less than 4. Radiation damage to the glass causes insignificant changes in leaching performance

  14. Comparison of leaching characteristics of heavy metals from bottom and fly ashes in Korea and Japan.

    Science.gov (United States)

    Shim, Young-Sook; Rhee, Seung-Whee; Lee, Woo-Keun

    2005-01-01

    The objective of this research was to compare the leaching characteristics of heavy metals such as cadmium, chromium, copper, nickel, lead, etc., in Korean and Japanese municipal solid waste incineration (MSWI) ash. The rate of leaching of heavy metal was measured by KSLT and JTL-13, and the amount of heavy metals leached was compared with the metal content in each waste component. Finally, bio-availability testing was performed to assess the risks associated with heavy metals leached from bottom ash and fly ash. From the results, the value of neutralization ability in Japanese fly ash was four times higher than that in Korean fly ash. The reason was the difference in the content of Ca(OH)(2) in fly ash. The amount of lead leached exceeded the regulatory level in both Japanese and Korean fly ash. The rate of leaching was relatively low in ash with a pH in the range of 6-10. The bio-availability test in fly ash demonstrated that the amount of heavy metals leached was Pb>Cd>Cr, but the order was changed to Pb>Cr>Cd in the bottom ash. The leaching concentration of lead exceeded the Japanese risk level in all fly ashes from the two countries, but the leaching concentration of cadmium exceeded the regulatory level in Korean fly ash only.

  15. Comparison of leaching characteristics of heavy metals from bottom and fly ashes in Korea and Japan

    International Nuclear Information System (INIS)

    Shim, Young-Sook; Rhee, Seung-Whee; Lee, Woo-Keun

    2005-01-01

    The objective of this research was to compare the leaching characteristics of heavy metals such as cadmium, chromium, copper, nickel, lead, etc., in Korean and Japanese municipal solid waste incineration (MSWI) ash. The rate of leaching of heavy metal was measured by KSLT and JTL-13, and the amount of heavy metals leached was compared with the metal content in each waste component. Finally, bio-availability testing was performed to assess the risks associated with heavy metals leached from bottom ash and fly ash. From the results, the value of neutralization ability in Japanese fly ash was four times higher than that in Korean fly ash. The reason was the difference in the content of Ca(OH) 2 in fly ash. The amount of lead leached exceeded the regulatory level in both Japanese and Korean fly ash. The rate of leaching was relatively low in ash with a pH in the range of 6-10. The bio-availability test in fly ash demonstrated that the amount of heavy metals leached was Pb > Cd > Cr, but the order was changed to Pb > Cr > Cd in the bottom ash. The leaching concentration of lead exceeded the Japanese risk level in all fly ashes from the two countries, but the leaching concentration of cadmium exceeded the regulatory level in Korean fly ash only

  16. Measurement of leached hulls

    International Nuclear Information System (INIS)

    Reilly, T.D.

    1979-07-01

    Leached hulls are the short lengths of fuel rod cladding and fuel element hardware which constitute a major waste product of a reprocessing plant employing a chop-and-leach head-end process. The small, undissolved fuel residue (0.1 to 1.0% of original fuel content) which is discarded with this waste must be measured for safeguards, material accountability, and process control reasons. This report gives a critical analysis of hull measurement techniques involving the analysis of fission product gamma rays, spontaneous fission neutrons from curium, and delayed neutron activation. Major emphasis is given to the measurement of 2186-keV gamma rays from 144 Ce-- 144 Pr. A detailed description of typical leached hull characteristics is presented at the beginning of the report. An extensive review of experience gained from existing hull measurement systems in the United Kingdom, France, Japan, Germany, Italy, and the United States is presented

  17. Using microbiological leaching method to remove heavy metals from sludge

    Directory of Open Access Journals (Sweden)

    Zhuyu Gu

    2017-01-01

    Full Text Available Microbial leaching is one of the most effective methods to remove heavy metals from sludge. In the conducted researches, the sludge samples were processed with Thiobacillus ferrooxidans and Thiobacillus thiooxidans obtained via cultivation, extraction and purification processes. Heavy metals such as Pb, Cd, Cu and Ni were leached from sludge by Thiobacillus ferrooxidans and Thiobacillus thiooxidans within different substrate concentration and pH value conditions. It is defined that from the point of view of economy and efficiency the optimal concentration of FeSO4.7H2O and sulfur for bio-leaching process was 0.2 g. The leaching rates of heavy metals such as Pb, Cd, Cu and Ni of the same concentration were 74.72%, 81.54%, 70.46% and 77.35% respectively. However, no significant differences depending on the pH value among the leaching rates were defined, even for the pH value of 1.5. Along with the removal of heavy metals from sludge, the organic matter, N, P, K were also leached to some extent. The losing rate of phosphorus was the highest and reached 38.44%. However, the content of organic matter, N, P, K in the processed sludge were higher in comparison with level I of the National Soil Quality Standards of China. Ecological risk of heavy metals in sludge before and after leaching was assessed by Index of Geo-accumulation (Igeo and comprehensive potential risk (RI. The results of research defined that the content of heavy metals in sludge meets the level of low ecological risk after leaching and their contents is lower in comparison with the National Agricultural Sludge Standard of China. Sludge leached by biological methods is possible to use for treatment for increasing soil fertility.

  18. Accelerated leach test development program

    International Nuclear Information System (INIS)

    Fuhrmann, M.; Pietrzak, R.F.; Heiser, J.; Franz, E.M.; Colombo, P.

    1990-11-01

    In FY 1989, a draft accelerated leach test for solidified waste was written. Combined test conditions that accelerate leaching were validated through experimental and modeling efforts. A computer program was developed that calculates test results and models leaching mechanisms. This program allows the user to determine if diffusion controls leaching and, if this is the case, to make projections of releases. Leaching mechanisms other than diffusion (diffusion plus source term partitioning and solubility limited leaching) are included in the program is indicators of other processes that may control leaching. Leach test data are presented and modeling results are discussed for laboratory scale waste forms composed of portland cement containing sodium sulfate salt, portland cement containing incinerator ash, and vinyl ester-styrene containing sodium sulfate. 16 refs., 38 figs., 5 tabs

  19. Urananite leaching: literature survey

    Energy Technology Data Exchange (ETDEWEB)

    Grisham, G.F.; Bryant, E.A.; Williams, K.E.

    1979-04-01

    A literature survey was undertaken to provide background materials for a series of experiments involving the interaction of spent uranium dioxide fuel with various environments. Notes and references pertaining to the basic properties of UO/sub 2/ as produced and after reactor exposure are presented. The use of computerized literature searches is illustrated with specific topics related to leaching experiments. 57 references.

  20. Urananite leaching: literature survey

    International Nuclear Information System (INIS)

    Grisham, G.F.; Bryant, E.A.; Williams, K.E.

    1979-04-01

    A literature survey was undertaken to provide background materials for a series of experiments involving the interaction of spent uranium dioxide fuel with various environments. Notes and references pertaining to the basic properties of UO 2 as produced and after reactor exposure are presented. The use of computerized literature searches is illustrated with specific topics related to leaching experiments. 57 references

  1. In-situ uranium leaching

    International Nuclear Information System (INIS)

    Dotson, B.J.

    1986-01-01

    This invention provides a method for improving the recovery of mineral values from ore bodies subjected to in-situ leaching by controlling the flow behaviour of the leaching solution. In particular, the invention relates to an in-situ leaching operation employing a foam for mobility control of the leaching solution. A foam bank is either introduced into the ore bed or developed in-situ in the ore bed. The foam then becomes a diverting agent forcing the leaching fluid through the previously non-contacted regions of the deposit

  2. Leaching Mechanisms Program. Annual report

    International Nuclear Information System (INIS)

    Dougherty, D.; Colombo, P.; Doty, R.; Fuhrmann, M.

    1984-09-01

    The primary goal of this work is to determine the leaching mechanisms of a variety of matrix materials either in use or being considered for the solidification of low-level radioactive wastes by defense and commercial waste generators. Since this program is new and did not formally begin until May of FY 84, the results reported here are few and preliminary. Efforts were concentrated in the following activities: (1) The literature search for leaching data and proposed leaching models and mechanisms for low-level waste. (2) Data base development for leaching data being compiled from the literature and from the leaching experiments in this program. (3) The selection of solidification agents for the experimental part of the program. (4) Fabrication of leach samples and initiation of leach testing. 28 references, 9 figures, 4 tables

  3. Commercial experimental on bacteria heap leaching of uranium ore from Caotaobei mining area in Ganzhou uranium mine

    International Nuclear Information System (INIS)

    Fan Baotuan; Meng Yunsheng; Liu Jian; Xiao Jinfeng; Chen Sencai; Cao Jianbo; Wu Yichang; Liu Chengwu

    2002-01-01

    The author presents the result of commercial experiment on bacteria heap leaching of uranium ore from Caotaobei mining area in Ganzhou Uranium Mine and summarizes the heap situation, installation of spraying and sprinkling devices, and operation management of continuous oxidizing tank of bio-membrane. The leaching rate is 92.95% and 91.88% respectively by liquid and residue measurement during 85 d bacterial leaching experiment. The acid consumption is 2.1% and the total liquid-solid ratio is 2.9 m 3 /t. Compared with conventional heap leaching, the time of bacteria heap leaching shorted about 75 d, the acid consumption reduced by 0.35% and the leaching rate improved by 2%. It is an optimize plan to reform the heap leaching technology for Caotaobei ore

  4. Leaching materials from cavities

    International Nuclear Information System (INIS)

    Hodgson, T.D.; Jordan, T.W.J.

    1980-01-01

    A material is leached from a cavity by contacting the material with a liquid and subjecting the liquid to a number of pressure cycles, each pressure cycle involving a decrease in pressure to cause boiling of the liquid, followed by a rise in pressure to inhibit the boiling. The method may include the step of heating the liquid to a temperature near to its boiling point. The material may be nuclear fuel pellets or calcium carbonate pellets. (author)

  5. Organic compounds leached from fast pyrolysis mallee leaf and bark biochars.

    Science.gov (United States)

    Lievens, Caroline; Mourant, Daniel; Gunawan, Richard; Hu, Xun; Wang, Yi

    2015-11-01

    Characterization of organic compounds leached from biochars is essential in assessing the possible toxicity of the biochar to the soils' biota. In this study the nature of the leached organic compounds from Mallee biochars, produced from pyrolysis of Mallee leaf and bark in a fluidised-bed pyrolyser at 400 and 580°C was investigated. Light bio-oil compounds and aromatic organic compounds were investigated. The 'bio-oil like' light compounds from leaf and bark biochars 'surfaces were obtained after leaching the chars with a solvent, suitable to dissolve the respective bio-oils. GC/MS was implemented to investigate the leachates. Phenolics, which are potentially harmful toxins, were detected and their concentration shown to be dependent on the char's origin and the char production temperature. Further, to simulate biochars amendment to soils, the chars were leached with water. The water-leached aromatic compounds from leaf and bark biochars were characterized using UV-fluorescence spectroscopy. Those results suggested that biochars contain leachable compounds of which the nature and amount is dependent on the biomass feedstock, pyrolysis temperature and leaching time. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Leaching From Biomass Gasification Residues

    DEFF Research Database (Denmark)

    Allegrini, Elisa; Boldrin, Alessio; Polletini, A.

    2011-01-01

    The aim of the present work is to attain an overall characterization of solid residues from biomass gasification. Besides the determination of chemical and physical properties, the work was focused on the study of leaching behaviour. Compliance and pH-dependence leaching tests coupled with geoche......The aim of the present work is to attain an overall characterization of solid residues from biomass gasification. Besides the determination of chemical and physical properties, the work was focused on the study of leaching behaviour. Compliance and pH-dependence leaching tests coupled...

  7. Microbiological Leaching; an Environmentally Friendly and Cost Effective Method for Extraction of Metals

    Directory of Open Access Journals (Sweden)

    Ghobeiti-Hasab Mehdi

    2018-02-01

    Full Text Available Finding a cleaner, environmentally friendly and cost-effective way of metal and mineral extraction has a great importance in today’s world. Using microorganisms in bio-leaching and bio-oxidation process is of great value. From Archaea to bacteria and fungi, microorganisms can play an important role in extraction of metals from mine drainage and un-accessible sources, both in aquatic and terrestrial environments. Optimization of environmental factors such as the temperature, pH and substrate concentration is crucially important to access the optimum extraction of selected metals from an ore or mine drainage. The present paper will review the bio-leaching and bio-oxidation process of minerals with emphasis on the most well-known species of bacterial communities of such ability, through the literature.

  8. Leaching Test Relationships, Laboratory-to-Field Comparisons and Recommendations for Leaching Evaluation using the Leaching Environmental Assessment Framework (LEAF)

    Science.gov (United States)

    This report presents examples of the relationships between the results of laboratory leaching tests, as defined by the Leaching Environmental Assessment Framework (LEAF) or analogous international test methods, and leaching of constituents from a broad range of materials under di...

  9. Defining Effective Salt Leaching Regions Between Drains

    OpenAIRE

    ANAPALI, Ömer; ŞAHİN, Üstün; ÖZTAŞ, Taşkın; HANAY, Abdurrahman

    2014-01-01

    The application of sufficient amounts of leaching water by means of an effective method is very important in the management and reclamation of saline and sodic soils. Reclamation cannot be achieved with insufficient leaching water application, while excess water application may cause severe problems in soil. Knowledge of the leaching regions and intensities may help to control the amounts of leaching water through effective leaching methods in areas of limited leaching. This study was und...

  10. Bio energy: Bio fuel - Properties and Production

    International Nuclear Information System (INIS)

    Wilhelmsen, Gunnar; Martinsen, Arnold Kyrre; Sandberg, Eiliv; Fladset, Per Olav; Kjerschow, Einar; Teslo, Einar

    2001-01-01

    This is Chapter 3 of the book ''Bio energy - Environment, technique and market''. Its main sections are: (1) Definitions and properties, (2) Bio fuel from the forest, (3) Processed bio fuel - briquettes, pellets and powder, (4) Bio fuel from agriculture, (5) Bio fuel from agro industry, (6) Bio fuel from lakes and sea, (7) Bio fuel from aquaculture, (8) Bio fuel from wastes and (9) Hydrogen as a fuel. The exposition largely describes the conditions in Norway. The chapter on energy from the forest includes products from the timber and sawmill industry, the pulp and paper industry, furniture factories etc. Among agricultural sources are straw, energy forests, vegetable oil, bio ethanol, manure

  11. To accelerate technology of in situ leaching and heap leaching for mining mineral resources of China

    International Nuclear Information System (INIS)

    Luo Mei

    1999-01-01

    Recently, in situ leaching and heap leaching are the most advanced technology for mining low-grade mineral resources in the world. The author briefly expounds the basic concept and advantages of in situ leaching and heap leaching and deals with the main research content of the hydrometallurgical technology of in situ leaching and heap leaching, its development and present application at home and abroad. Having expounded the gap existing between China's technology of in situ leaching and heap leaching and the foreign technology, the author forecasts the prospects of accelerating the mining of China's mineral resources by using the technology of in situ leaching and heap leaching

  12. Disposal of leached residual in heap leaching by neutralization

    International Nuclear Information System (INIS)

    Wang Jingmin

    1993-01-01

    The disposal results of leached residual with lime are described. Using the ratio of residual to lime being 100 : 1 the ideal disposal results were obtained with the effluent of the neutralized residual close to neutral

  13. Metal removal from Municipal Solid Waste Incineration fly ash: A comparison between chemical leaching and bioleaching.

    Science.gov (United States)

    Funari, V; Mäkinen, J; Salminen, J; Braga, R; Dinelli, E; Revitzer, H

    2017-02-01

    Bio- and hydrometallurgical experimental setups at 2-l reactor scale for the processing of fly ash from municipal waste incinerators were explored. We aimed to compare chemical H 2 SO 4 leaching and bioleaching; the latter involved the use of H 2 SO 4 and a mixed culture of acidophilic bacteria. The leaching yields of several elements, including some of those considered as critical (Mg, Co, Ce, Cr, Ga, Nb, Nd, Sb and Sm), are provided. At the end of the experiments, both leaching methods resulted in comparable yields for Mg and Zn (>90%), Al and Mn (>85%), Cr (∼65%), Ga (∼60%), and Ce (∼50%). Chemical leaching showed the best yields for Cu (95%), Fe (91%), and Ni (93%), whereas bioleaching was effective for Nd (76%), Pb (59%), and Co (55%). The two leaching methods generated solids of different quality with respect to the original material as we removed and significantly reduced the metals amounts, and enriched solutions where metals can be recovered for example as mixed salts for further treatment. Compared to chemical leaching the bioleaching halved the use of H 2 SO 4 , i.e., a part of agent costs, as a likely consequence of bio-produced acid and improved metal solubility. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Mechanism for elevated temperature leaching

    International Nuclear Information System (INIS)

    Kenna, B.T.; Murphy, K.D.

    1979-01-01

    Long-term, elevated temperature leaching and subsequent electron microprobe analysis of simulated waste glass and ceramic materials have been completed. A cyclic leaching pattern was found in all systems over a 20-month period. It appears that the leaching of mobile ions by simple diffusional processes is modified by more complex chemical interactions. The release of immobile ions is primarily a function of their chemical interactions in the matrix which suggests that these ions may be complex species when released into solution. A mechanism is proposed which incorporates these ideas and the cyclic phenomenon observed

  15. Leaching of concrete : the leaching process : extrapolation of deterioration : effect on the structural stability

    OpenAIRE

    Fagerlund, Göran

    2000-01-01

    The leaching process when water attacks concrete, and the effect of leaching on the strength and durability of a concrete structure, is analysed theoretically. Technique for prediction of the future leaching and structural stability is outlined. The analysis is to a certain extent supported by data from literature. The leaching process is divided in five different types: 1: Pure surface leaching 2: Surface leaching involving erosion 3: Homogeneous leaching over the entire structure 4...

  16. Comparison of leaching tests and study of leaching mechanisms

    International Nuclear Information System (INIS)

    Amarantos, S.G.; Papadokostaki, K.G.; Petropoulos, J.H.

    1985-10-01

    The present work is concerned first with the study of certain aspects of the leaching kinetics of Cs + and Sr ++ embedded in cement, as Cs 2 SO 4 and SrSO 4 , and in particular: (a) the comparative evaluation of leaching in (i) stagnant, (ii) stirred and (iii) continuously flowing (modified Soxhlet) water, (b) the effect of atmospheric CO 2 on elution, (c) the effect of temperature changes during leaching. Secondly, model kinetic studies were carried out using cellulose acetate incorporating SrSO 4 , CaSO 4 or NaCl. The main results obtained were: (1) Cs leaching rates were not significantly affected by the leaching method or by the presence of atmospheric CO 2 . The embedded Cs exists in relatively easily leachable and less rapidly leachable (most probably located within the gel regions) forms. (2) Elution of Sr is retarded by stagnant and infrequently renewed leachant (method (i)) and by the presence of atmospheric CO 2 ; leaching method (iii), which tends to minimize both of these effects, gave the highest elution rates. (3) The observed elution kinetics in the case of cellulose acetate-CaSO 4 or SrSO 4 conform to the Higuchi model, but a more elaborate theory is needed for the cellulose acetate-NaCl system. (author)

  17. LEACH-A: An Adaptive Method for Improving LEACH Protocol

    Directory of Open Access Journals (Sweden)

    Jianli ZHAO

    2014-01-01

    Full Text Available Energy has become one of the most important constraints on wireless sensor networks. Hence, many researchers in this field focus on how to design a routing protocol to prolong the lifetime of the network. The classical hierarchical protocols such as LEACH and LEACH-C have better performance in saving the energy consumption. However, the choosing strategy only based on the largest residue energy or shortest distance will still consume more energy. In this paper an adaptive routing protocol named “LEACH-A” which has an energy threshold E0 is proposed. If there are cluster nodes whose residual energy are greater than E0, the node of largest residual energy is selected to communicated with the base station; When all the cluster nodes energy are less than E0, the node nearest to the base station is select to communication with the base station. Simulations show that our improved protocol LEACH-A performs better than the LEACH and the LEACH-C.

  18. Mutualism between autotrophic and heterophic bacteria in leaching of low grade ores

    International Nuclear Information System (INIS)

    Khalid, Z.M.; Naeveke, R.

    1991-01-01

    During solubilization processes of low grade sulphidic ores, the auto trophic bacteria oxidize reduced sulphur compounds and ferrous iron to sulphates and ferric iron respectively. The ore leaching bio topes are not only colonized by auto trophic bacteria (Thiobacillus spp., Leptospirillum ferro oxidans and sulfolobus sp.) but the heterotrophic microorganisms, including bacteria and fungi of various species are also found in these habitats. The autotrophs, in addition to energy metabolism, also produce organic compounds which in excess amount inhibit their growth. Through the utilization of such compounds and also through the production of carbon dioxide and ammonia, these heterotorphs can help bio leaching processes. Effect of one of the heterotrophs; methylobacterium sp., a nitrogen scavenger, found in as association with the thio bacilli in one of the leaching bio tope in Germany was studied in leaching of a carbonate bearing complex (containing copper, iron, zinc and lead) sulphidic ore, in shake flask studies. T. ferro oxidans (Strain F-40) reported to be non nitrogen fixer and strain F-41, a nitrogen fixing thiobacillus were studied for leachability behaviour alone and in combination with T. thio oxidans (lacking nitrogen fixing ability) using media with and without added ammonium nitrogen. In addition the effect of methylobacterium sp. (alt-25) was also tested with the afore mentioned combinations. Nitrogen fixation by T. ferro oxidans did not suffice the nitrogen requirement and the leaching system in laboratory needed addition of nitrogen. The heterotrophic nitrogen scavenger also did not have a positive influence in nitrogen limited system. In case where ammonium nitrogen was also provided in the media, this heterotroph had a negative in own growth and leaving lesser amount available for thio bacilli. This high amount of acid is a limiting factor in bio leaching of high carbonate uranium ores. Uranium ore ecosystems have also been found to contain

  19. Reduction of inorganics from macroalgae Laminaria digitata and spent mushroom compost (SMC) by acid leaching and selective hydrothermal liquefaction

    DEFF Research Database (Denmark)

    Toor, Saqib Sohail; Jasiunas, Lukas; Xu, Chunbao (Charles)

    2018-01-01

    Hydrothermal liquefaction (HTL) is a promising route for producing bio-crude from various biomass feedstocks. However, high content of inorganic constituents in biomass like macroalgae Laminaria digitata and spent mushroom compost (SMC) affect the conversion process and the resulting fuel products....... This research studied the effects of different acid leaching treatments on such feedstocks, subsequent HTL, and bio-crude properties. Leaching treatments were performed using five different agents: deionized water, acetic acid, citric acid, sulfuric acid, and hydrochloric acid. Performance of leaching...... was evaluated by analyzing both leached biomass and HTL products by elemental analysis, ash content, inductively coupled plasma (ICP) analysis, and X-ray diffraction (XRD) analysis. Catalytic and non-catalytic HTL of both feedstocks before and after treatment were performed in a 10-mL microreactor at 400 °C...

  20. Next Generation of Leaching Tests

    Science.gov (United States)

    A corresponding abstract has been cleared for this presentation. The four methods comprising the Leaching Environmental Assessment Framework are described along with the tools to support implementation of the more rigorous and accurate source terms that are developed using LEAF ...

  1. Pressure leaching of chalcopyrite concentrate

    Science.gov (United States)

    Aleksei, Kritskii; Kirill, Karimov; Stanislav, Naboichenko

    2018-05-01

    The results of chalcopyrite concentrate processing using low-temperature and high-temperature sulfuric acid pressure leaching are presented. A material of the following composition was used, 21.5 Cu, 0.1 Zn, 0.05 Pb, 0.04 Ni, 26.59 S, 24.52 Fe, 16.28 SiO2 (in wt.%). The influence of technological parameters on the degree of copper and iron extraction into the leach solution was studied in the wide range of values. The following conditions were suggested as the optimal for the high-temperature pressure leaching: t = 190 °C, PO2 = 0.5 MPa, CH2SO4 = 15 g/L, L:S = 6:1. At the mentioned parameters, it is possible to extract at least 98% Cu from concentrate into the leaching solution during 100 minutes. The following conditions were suggested as optimal for the low-temperature pressure leaching: t = 105 °C, PO2 = 1.3-1.5 MPa, CH2SO4 = 90 g/L, L:S = 10:1. At the mentioned parameters, it is possible to extract up to 83% Cu from the concentrate into the leach solution during 300-360 minutes.

  2. Indirection and computer security.

    Energy Technology Data Exchange (ETDEWEB)

    Berg, Michael J.

    2011-09-01

    The discipline of computer science is built on indirection. David Wheeler famously said, 'All problems in computer science can be solved by another layer of indirection. But that usually will create another problem'. We propose that every computer security vulnerability is yet another problem created by the indirections in system designs and that focusing on the indirections involved is a better way to design, evaluate, and compare security solutions. We are not proposing that indirection be avoided when solving problems, but that understanding the relationships between indirections and vulnerabilities is key to securing computer systems. Using this perspective, we analyze common vulnerabilities that plague our computer systems, consider the effectiveness of currently available security solutions, and propose several new security solutions.

  3. Cadmium telluride leaching behavior: Discussion of Zeng et al. (2015).

    Science.gov (United States)

    Sinha, Parikhit

    2015-11-01

    Zeng et al. (2015) evaluate the leaching behavior and surface chemistry of II-VI semiconductor materials, CdTe and CdSe, in response to pH and O2. Under agitation in acidic and aerobic conditions, the authors found approximately 3.6%-6.4% (w/w) solubility of Cd content in CdTe in the Toxicity Characteristic Leaching Procedure (TCLP), Waste Extraction Test (WET), and dissolution test, with lower solubility (0.56-0.58%) under agitation in acidic and anoxic conditions. This range is comparable with prior long-term transformation and dissolution testing and bio-elution testing of CdTe (2.3%-4.1% w/w solubility of Cd content in CdTe). The implications for potential leaching behavior of CdTe-containing devices require further data. Since CdTe PV modules contain approximately 0.05% Cd content by mass, the starting Cd content in the evaluation of CdTe-containing devices would be lower by three orders of magnitude than the starting Cd content in the authors' study, and leaching potential would be further limited by the monolithic glass-adhesive laminate-glass structure of the device that encapsulates the semiconductor material. Experimental evaluation of leaching potential of CdTe PV modules crushed by landfill compactor has been conducted, with results of TCLP and WET tests on the crushed material below regulatory limits for Cd. CdTe PV recycling technology has been in commercial operation since 2005 with high yields for semiconductor (95%) and glass (90%) recovery. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. NEXT GENERATION LEACHING TESTS FOR EVALUATING LEACHING OF INORGANIC CONSTITUENTS

    Science.gov (United States)

    In the U.S. as in other countries, there is increased interest in using industrial by-products as alternative or secondary materials, helping to conserve virgin or raw materials. The LEAF and associated test methods are being used to develop the source term for leaching or any i...

  5. Bio-functionalization of conductive textile materials with redox enzymes

    Science.gov (United States)

    Kahoush, M.; Behary, N.; Cayla, A.; Nierstrasz, V.

    2017-10-01

    In recent years, immobilization of oxidoreductase enzymes on electrically conductive materials has played an important role in the development of sustainable bio-technologies. Immobilization process allows the re-use of these bio-catalysts in their final applications. In this study, different methods of immobilizing redox enzymes on conductive textile materials were used to produce bio-functionalized electrodes. These electrodes can be used for bio-processes and bio-sensing in eco-designed applications in domains such as medicine and pollution control. However, the main challenge facing the stability and durability of these electrodes is the maintenance of the enzymatic activity after the immobilization. Hence, preventing the enzyme’s denaturation and leaching is a critical factor for the success of the immobilization processes.

  6. Nano-bio-sensing

    CERN Document Server

    Carrara, Sandro

    2011-01-01

    This book examines state-of-the-art applications of nano-bio-sensing. It brings together researchers from nano-electronics and bio-technology, providing multidisciplinary content from nano-structures fabrication to bio-sensing applications.

  7. Implementation of the Leaching Environmental Assessment Framework

    Science.gov (United States)

    New leaching tests are available in the U.S. for developing more accurate source terms for use in fate and transport models. For beneficial use or disposal, the use of the leaching environmental assessment framework (LEAF) will provide leaching results that reflect field condit...

  8. Standard leach tests for nuclear waste materials

    International Nuclear Information System (INIS)

    Strachan, D.M.; Barnes, B.O.; Turcotte, R.P.

    1980-01-01

    Five leach tests were conducted to study time-dependent leaching of waste forms (glass). The first four tests include temperature as a variable and the use of three standard leachants. Three of the tests are static and two are dynamic (flow). This paper discusses the waste-form leach tests and presents some representative data. 4 figures

  9. Copper leaching of MSWI bottom ash co-disposed with refuse: effect of short-term accelerated weathering.

    Science.gov (United States)

    Su, Lianghu; Guo, Guangzhai; Shi, Xinlong; Zuo, Minyu; Niu, Dongjie; Zhao, Aihua; Zhao, Youcai

    2013-06-01

    Co-disposal of refuse with municipal solid waste incinerator (MSWI) bottom ash (IBA) either multi-layered as landfill cover or mixed with refuse could pose additional risk to the environment because of enhanced leaching of heavy metals, especially Cu. This study applied short-term accelerated weathering to IBA, and monitored the mineralogical and chemical properties of IBA during the weathering process. Cu extractability of the weathered IBA was then evaluated using standard leaching protocols (i.e. SPLP and TCLP) and co-disposal leaching procedure. The results showed that weathering had little or no beneficial effect on Cu leaching in SPLP and TCLP, which can be explained by the adsorption and complexation of Cu with DOM. However, the Cu leaching of weathered IBA was reduced significantly when situated in fresh simulated landfill leachate. This was attributed to weakening Cu complexation with fulvic acid or hydrophilic fractions and/or intensifying Cu absorption to neoformed hydr(oxide) minerals in weathered IBA. The amount of total leaching Cu and Cu in free or labile complex fraction (the fraction with the highest mobility and bio-toxicity) of the 408-h weathered IBA were remarkably decreased by 86.3% and 97.6% in the 15-day co-disposal leaching test. Accelerated weathering of IBA may be an effective pretreatment method to decrease Cu leaching prior to its co-disposal with refuse. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Measurement of leach rates: a review

    International Nuclear Information System (INIS)

    Mendel, J.E.

    1982-01-01

    A historical perspective of the techniques that can be used to measure the leach rate of radioactive waste forms is presented. The achievement of leach rates that are as low as possible has been an important goal ever since the development of solidification processes for liquid radioactive wastes began in the 1950's. Leach tests can be divided into two major categories, dynamic and static, based on whether or not the leachant in contact with the test specimen is changed during the course of the test. Both types of tests have been used extensively. The results of leach tests can be used to compare waste forms, and that has been a major purpose of leach data heretofore; increasingly, however, the data now are needed for predicting long-term leaching behavior during geologic disposal. This requirement is introducing new complexities into leach testing methodology. 3 figures, 2 tables

  11. [Soil Phosphorus Forms and Leaching Risk in a Typically Agricultural Catchment of Hefei Suburban].

    Science.gov (United States)

    Fan, Hui-hui; Li, Ru-zhong; Pei, Ting-ting; Zhang, Rui-gang

    2016-01-15

    To investigate the soil phosphorus forms and leaching risk in a typically agricultural catchment of Ershibu River in Hefei Suburban, Chaohu Lake basin, 132 surface soil samples were collected from the catchment area. The spatial distribution of total phosphorus (TP) and bio-available phosphorus (Bio-P), and the spatial variability of soil available phosphorus (Olsen-P) and easy desorption phosphorus (CaCl2-P) were analyzed using the Kriging technology of AreGIS after speciation analysis of soil phosphorus. Moreover, the enrichment level of soil phosphorus was studied, and the phosphorus leaching risk was evaluated through determining the leaching threshold value of soil phosphorus. The results showed that the samples with high contents of TP and Bio-P mainly located in the upstream of the left tributary and on the right side of local area where two tributaries converged. The enrichment rates of soil phosphorus forms were arranged as follows: Ca-P (15.01) > OP (4.16) > TP (3. 42) > IP (2.94) > Ex-P (2.76) > Fe/Al-P (2.43) > Olsen-P (2.34). The critical value of Olsen-P leaching was 18.388 mg x kg(-1), and the leaching samples with values higher than the threshold value accounted for 16.6% of total samples. Generally, the high-risk areas mainly occurred in the upstream of the left tributary, the middle of the right tributary and the local area of the downstream of the area where two tributaries converged.

  12. Trend towards reverse leach process

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    The South African gold mining industry is making notable strides in improving recovery methods for both gold and uranium with significant additions to profits because of higher efficiencies and reductions in costs in the recovery processes. The most notable step on the gold side recently is the adoption of the reverse leach process at Buffelsfontein and Western Deep Levels. This process was pioneered at Hartebeesfontein as far back as 1975 and when introduced there resulted in a two and a half per cent improvement in recovery efficiencies. The essence of reverse leaching under which the uranium is recovered before the gold is the fact that the gold partly coated with iron oxide or locked in uranite, is exposed to be recovered later by cyanidation

  13. A study on the selection of indigenous leaching-bacteria for effective bioleaching

    Science.gov (United States)

    Oh, S. J.; Cho, K. H.; Kim, B. J.; Choi, N. C.; Park, C. Y.

    2012-04-01

    Bioleaching technology, which is based on the ability of microorganisms to transform solid compounds into soluble and extractable valuable elements that can be recovered, has been rapidly developed in recent decades for its advantages, which include mild reaction condition, low energy consumption, simple process, low environmental impact and being suitable for low grade mine tailings and residues. The bacteria activities (survival, adaptation of toxically environments etc.) in the bioleaching technology play a key role in the solubilization of metals. The purpose of this study was to selection of optimal leaching-bacteria through changed pH and redox potential on bio-oxidation in batch experiments for successful bioleaching technology. Twenty three indigenous bacteria used throughout this study, leaching-bacteria were obtained from various geochemical conditions; bacteria inhabitation type (acid mine drainage, mine wastes leachate and sulfur hot springs) and base-metal type (sulfur, sulfide, iron and coal). Bio-oxidation experiment result was showed that 9 cycles (1 cycle - 28days) after the leaching-bacteria were inoculated to a leaching medium, pH was observed decreasing and redox potential increased. In the bacteria inhabitation type, bio-oxidation of sulfur hot springs bacteria was greater than other types (acid mine drainage and mine wastes leachate). In addition, bio-oxidation on base-metal type was appeared sulfur was greater than other types (sulfide, iron and coal). This study informs basic knowledge when bacteria apply to eco-/economic resources utilization studies including the biomining and the recycling of mine waste system.

  14. Uranium leaching by fungal metabolite

    International Nuclear Information System (INIS)

    Wang Yongdong; Li Guangyue; Ding Dexin; Hu Nan

    2012-01-01

    To explore new means of bioleaching, one strain of high-yielding fungi-Aspergillus niger which could produce organic acids was separated and purified from soil samples of uranium mine. The influence of cultural temperature, initial pH value, inoculum sizes on its growth characteristics were carried out. And the tests of uranium leaching of metabolin of Aspergillus niger were operated. On these tests, the effects of metabolin of Aspergillus niger with different pH value produced in the diverse culture temperature on uranium leaching were investigated. The results show that this strain of Aspergillus niger can grow best under the following conditions: the temperature is 37℃, the initial pH value is 7.0, the inoculum sizes is 2% (the OD value of the spores solution is 0.06). The uranium extraction effects relative to the final pH value of the cultures. and the maximum leaching rates is 83.05% when the pH value is 2.3. (authors)

  15. Bio energocentrum

    OpenAIRE

    Vitoulová, Alena

    2013-01-01

    Bakalářská práce byla zpracována jako projekt pro provedení stavby na základě ateliérové práce z 2. semestru. Areál Bio energocentrum, Modřice u Brna je komplexem čtyř vzájemně propojených budov dělených podle jejich funkcí – Budova pro veřejnost, produkční skleník, objekt pro zaměstnance, zařízení pro výrobu bioplynu. Konstrukční systém objektu je materiálově ze železobetonu, oceli a dřeva. Ideou urbanistického a architektonického řešení je jednoduchost tvarů, funkčnost a výstižnost záměru. ...

  16. Bacterial leaching of waste uranium materials.

    Science.gov (United States)

    Barbic, F F; Bracilović, D M; Krajincanić, B V; Lucić, J L

    1976-01-01

    The effect of ferrobacteria and thiobacteria on the leaching of waste uranium materials from which 70-80% of uranium was previously leached by classical chemical hydrometallurgical procedure has been investigated. The bacteria used are found in the ore and the mine water of Zletovska River locality, Yugoslavia. Parameters of biological leaching were examined in the laboratory. Leaching conditions were changed with the aim of increasing the amount of uranium leached. The effect of pyrite added to the waste materials before the beginning of leaching has also been examined. Uranium leaching is directly proportional to the composition and number of ferrobacteria and thiobacteria, and increased by almost twice the value obtained from the same starting materials without using bacteria. Increased sulphuric acid concentrations stimulate considerably the rate of leaching. Uranium leaching is increased up to 20% while sulphuric acid consumption is simultaneously decreased by the addition of pyrite. Uranium concentrations in starting waste materials used for leaching were extremely low (0.0278 and 0.372% U) but about 60% recovery of uranium was obtained, with relatively low consumption of sulphuric acid.

  17. Bacterial leaching of waste uranium materials

    International Nuclear Information System (INIS)

    Barbic, F.F.; Bracilovic, D.M.; Krajincanic, B.V.; Lucic, J.L.

    1976-01-01

    The effect of ferrobacteria and thiobacteria on the leaching of waste uranium materials from which 70-80% of uranium was previously leached by classical chemical hydrometallurgical procedure has been investigated. The bacteria used are found in the ore and the mine water of Zletovska River locality, Yugoslavia. Parameters of biological leaching were examined in the laboratory. Leaching conditions were changed with the aim of increasing the amount of uranium leached. The effect of pyrite added to the waste materials before the beginning of leaching has also been examined. Uranium leaching is directly proportional to the composition and number of ferrobacteria and thiobacteria, and increased by almost twice the value obtained from the same starting materials without using bacteria. Increased sulphuric acid concentrations stimulate considerably the rate of leaching. Uranium leaching is increased up to 20% while sulphuric acid consumption is simultaneously decreased by the addition of pyrite. Uranium concentrations in starting waste materials used for leaching were extremely low (0.0278 and 0.0372% U) but about 60% recovery of uranium was obtained, with relatively low consumption of sulphuric acid. (author)

  18. Application of percolation leaching in Fuzhou uranium mine

    International Nuclear Information System (INIS)

    Jiang Lang; Wang Haita; He Jiangming

    2006-01-01

    In order to solve these problems such as high cost by conventional agitation leaching, low permeability and low leaching rate by heap leach, a percolation leaching method was developed. Two-year's production results show that leaching rate of uranium is up to 90% by this method. Compared with conventional agitation leaching, the power, sulfuric acid and lime consumption by the percolation leaching decreased by 60%, 27% and 77% respectively. (authors)

  19. The structure of leached sodium borosilicate glass

    International Nuclear Information System (INIS)

    Bunker, B.C.; Tallant, D.R.; Headley, T.J.; Turner, G.L.; Kirkpatrick, R.J.

    1988-01-01

    Raman spectroscopy, solid state 29 Si, 11 B, 17 O, and 23 Na nuclear magnetic resonance spectroscopy, and transmission electron microscopy have been used to investigate how the structures of sodium borosilicate glasses change during leaching in water at pH 1, 9, and 12. Results show that the random network structure present prior to leaching is transformed into a network of small condensed ring structures and/or colloidal silica particles. The restructuring of leached glass can be rationalised on the basis of simple hydrolysis (depolymerisation) and condensation (repolymerisation) reactions involving Si-O-Si and Si-O-B bonds. The structural changes that occur during leaching influence the properties of the leached layer, including leaching kinetics, crazing and spalling, and slow crack growth. (author)

  20. The Danish Pesticide Leaching Assessment Programme

    DEFF Research Database (Denmark)

    Rosenbom, Annette Elisabeth; Brüsch, Walter Michael; Juhler, Rene K.

    In 1998, the Danish Parliament initiated the Pesticide Leaching Assessment Programme (PLAP), an intensive monitoring programme aimed at evaluating the leaching risk of pesticides under field conditions. The objective of the PLAP is to improve the scientific foundation for decision......-making in the Danish regulation of pesticides. The specific aim is to analyse whether pesticides applied in accordance with current regulations leach to groundwater in unacceptable concentrations. The programme currently evaluates the leaching risk of 41 pesticides and 40 degradation products at five agricultural......, thiamethoxam, tribenuronmethyl, and triasulfuron) did not leach during the 1999-2009 monitoring period. 13 of the applied pesticides exhibited pronounced leaching of the pesticide and/or their degradation product(-s) 1 m b.g.s. in yearly average concentrations exceeding 0.1 μg/l (maximum allowable...

  1. Biocatalytic and chemical leaching of a low-grade nickel laterite ore

    Science.gov (United States)

    Ciftci, Hasan; Atik, Suleyman; Gurbuz, Fatma

    2018-04-01

    Nickel and cobalt recovery from a low-grade nickel laterite ore, supplied from Çaldağ deposit (Manisa, Turkey) were investigated by bio and chemical leaching processes. The fungus, Aspergillus niger was used for biocatalytic leaching experiments. The effects of parameters (solid ratio and sucrose concentration) on the biocatalytic leaching of the ore were initially tested in flasks to obtain the optimum conditions for the A. niger. Then chemical leaching was applied as a comparison to bioleaching, using organic acids (citric, oxalic, acetic and gluconic acids) as well as a mixture of acids. According the results, the maximum dissolution yield of nickel, cobalt and iron were detected respectively as 95.3%, 74.3% and 50.0% by biocatalytic processes which containing 25% (w/v) sucrose and 1% (w/v) solids. The increase in the solid ratio adversely influenced the biocatalytic activity of A. niger. Finally, further tests in reactors (v = 1 and 10 L) were performed using the optimum conditions from the flask tests. The difference in metals recovery between biocatalytic and chemical leaching was significantly important. Bioleaching produced higher Ni and Co extractions (34.3-75.6%) than chemical process.

  2. The leaching characteristics of vitrified slag

    International Nuclear Information System (INIS)

    Zhang, Jinlong; Li, Yaojian; Tian, Junguo; Sheng, Hongzhi; Xu, Yongxiang

    2010-01-01

    Full Text: Plasma-arc technology was developed to fix the heavy metal of flying ash by the Institute of Mechanics, Chinese Academy of Sciences (CAS-IMECH). A direct current (DC) experimental facility of 30 kW with plasma-arc technology was setup to form vitrified slag. The additives (CaO, SiO 2 ) were added into the reactor to form vitrified slag and fix the heavy metal (Cr, Pb), under dissimilar condition (long and short heating-up time, natural and water cooling). Vitrified slag was broken into different particle size, from 0.1 mm to 1 cm. The particles with different specific surface area were used to study the leaching of heavy metals in vitrified slag rate of speed. The pH value of leaching solution are from 2 to 12, the experiment was kept at different external temperature, from 4 degree Celsius to 70 degree celsius, for 1 week to 1 month. Heavy metal leaching concentration was used to measure the chemical stability of vitrified slag. The results show that the higher specific surface area, the higher heavy metal leaching concentration, but when the specific surface area reaches a certain value, little change in leaching concentration. The impact of temperature on leaching concentration was not significant, from 4 degree Celsius to 70 degree Celsius. The leaching concentration increases with decreasing of the pH value of leaching solution when the pH value of leaching solution less than 7, and little change in concentration increases with pH value when the pH value of leaching solution more than 7. Compared with the leaching concentration after 1 month, the leaching concentration after 1 week has not changed significantly. (Author)

  3. A New Generation of Leaching Tests – The Leaching Environmental Assessment Framework

    Science.gov (United States)

    Provides an overview of newly released leaching tests that provide a more accurate source term when estimating environmental release of metals and other constituents of potential concern (COPCs). The Leaching Environmental Assessment Framework (LEAF) methods have been (1) develo...

  4. URANIUM LEACHING AND RECOVERY PROCESS

    Science.gov (United States)

    McClaine, L.A.

    1959-08-18

    A process is described for recovering uranium from carbonate leach solutions by precipitating uranium as a mixed oxidation state compound. Uranium is recovered by adding a quadrivalent uranium carbon;te solution to the carbonate solution, adjusting the pH to 13 or greater, and precipitating the uranium as a filterable mixed oxidation state compound. In the event vanadium occurs with the uranium, the vanadium is unaffected by the uranium precipitation step and remains in the carbonate solution. The uranium-free solution is electrolyzed in the cathode compartment of a mercury cathode diaphragm cell to reduce and precipitate the vanadium.

  5. Uranium extraction history using pressure leaching

    International Nuclear Information System (INIS)

    Fraser, K.S.; Thomas, K.G.

    2010-01-01

    Over the past 60 years of uranium process development only a few commercial uranium plants have adopted a pressure leaching process in their flowsheet. The selection of acid versus alkaline pressure leaching is related to the uranium and gangue mineralogy. Tetravalent (U"+"4) uranium has to be oxidized to hexavalent (U"+"6) uranium to be soluble. Refractory tetravalent uranium requires higher temperature and pressure, as practised in pressure leaching, for conversation to soluble hexavalent uranium. This paper chronicles the history of these uranium pressure leaching facilities over the past 60 years, with specific details of each design and operation. (author)

  6. A new Leaching System, Sheta Extractor

    International Nuclear Information System (INIS)

    Sheta, M.E.

    2008-01-01

    Moving of crushed solid ores against leaching solution in a continuous countercurrent arises a true technical problem. This invented system introduces a practical solution for such problem. Inside the system, the crushed ore is driving against gravity, whereas the leaching solution moves in the opposite direction. Contact between the two phases occurs with gentle stirring. After contact, discharging of the processed phases takes place automatically out the system. The system was investigated for uranium leaching from a coarse grained fraction (+2 --- -- -30 mm) of uranium mineralized granite sample. Uranium leaching percent reached to nearly 50% using sulfuric acid

  7. Heap leaching procedure for the Uranium extraction

    International Nuclear Information System (INIS)

    Shishahbore, M. R.

    2002-01-01

    Heap leaching of Uranium ores is currently in use in several countries. Before taking any decision for construction of heap in industrial scale, it is necessary to obtain the main factors that influence the heap leaching process, such as acid construction, acid solution flowrate, temperature of reaction, or size, ration of liquid to solid, permeability and suitable oxidant. To achieve the above parameters, small scale column leaching is usually recommended. In this project column leaching were carried out in 6 plexiglass column with 43.5 cm an height and 7.4 cm inner diameter. In each column closely 2.00 kg Uranium ore were leached by sulfuric acid. Leaching operation on Iranian ores from two different anomalies from the same area were investigated. In this project, six column were leached at different flowrate of eluent and effect of oxidant were investigated. Acid consumption were in the range of 60 - 144 kg per ton ore and recovery between 73.07% - 99.97%. Finally according to the results obtained, investigated that over are suitable to heap leaching technique. Al tough, to enforce of heap leaching project need to more experiments

  8. Method of continuous pressure leaching of ores

    International Nuclear Information System (INIS)

    Fiala, P.; Baloun, S.; Polansky, M.

    1987-01-01

    Ore leaching, especially suspensions of ground ore or fine ore fractions from physical treatment was divided into two operations. The former, i.e., ore mixing with technical grade concentrated sulfuric acid proceeded in a separate mixer. The mixture was then transported into an autoclave where the actual leaching proceeded for 2 to 4 hours. The extracted mixture was discharged through the autoclave bottom. The leaching autoclave used can be without any inner structures. The separation of mixing from the actual leaching allows processing ores with high levels of clay components, increasing operating reliability of the facility, reducing consumption of special structural materials and energy, and increasing process efficiency. (E.S.)

  9. Pedal indirect lymphangiography

    International Nuclear Information System (INIS)

    Lee, Kil Woo; Hong, Myung Sun; Kim, In Jae

    1994-01-01

    Recently, indirect lymphangiography has been developed as a relatively good and noninvasive imaging modality of the lymphatic system at extremities. But the disadvantage of the indirect lymphangiography is a low contrast ratio between the surrounding tissues and the contrast media in lymphatic vessels, because dimeric nonionic contrast media is water soluble and diluted in the proximal leg lymphatic vessels. We could have relatively better image than previously published images for the leg lymphatic system, when we injected contrast media with adequate high pressure in intradermal space of the interdigital areas at the foot dorsum. So, we would like to report the results. We could study all 9 lymphedemas(primary: 6, secondary: 3) from April 1990 to May 1993 on outpatient base. They were diagnosed as lymphedema clinically and radiologically. Ten ml of dimeric nonionic aget, iotrolan(Isovist 300) was injected into intradermal space with five 30-gauge needles. The injection speed was more than 0.2 ml/min. We have done one side pedal lymphangiogram in 30 minutes. The evaluation of the anterior superficial lymphatics was according to the criteria of the Weissleder. The results were as follows: 1. All lymphatic vessels from foot to inguinal area could be visualized. 2. Two or three inferior inguinal lymph nodes could be visualized about 42%. 3. The most common abnormal finding of the lymphedma was the neovascularization of the lymphatics on indirect pedal lymphangiogram. If we use adequate technique relatively high pressure injection, correct intradermal needle insertion, adequate soft tissue exposure technique indirect lymphangiography is considered to be a safe and noninvasive imaging modality for the evaluation of the lymphedema of lower extremity lymphatics including inferior inguinal lymph nodes

  10. Prediction of climate impacts on pesticide leaching to the aquatic environments

    Energy Technology Data Exchange (ETDEWEB)

    Henriksen, Hans Joergen; Rosenbom, A.; van der Keur, P.; Kjaer, J.; Sonnenborg, T. [GEUS Danmark, Copenhagen (Denmark); Olesen, J.E. [Aarhus Univ., Tjele (Denmark); Nistrup Joergensen, L. [Aarhus Unv., Slagelse (Denmark); Boessing Christensen, O. [Danmarks Meteorologiske Institut (DMI), Copenhagen (Denmark)

    2013-10-01

    The report evaluates direct (precipitation, actual evapotranspiration and temperature) and indirect (crop rotations, crop management, and pesticide use) climatic change effects on pesticide-leaching to groundwater and the aquatic environment by use of MACRO and MIKE SHE model. The analysis is based on five model pesticides: low-dose herbicides, ordinary herbicides, strongly sorbing herbicides, fungicides and insecticides, and selected farm types (arable and dairy) for the variable saturated sandy soil (Jyndevad) and loamy soil (Faardrup). The evaluation has the aim at describing the implications of future climatic factors on pesticide leaching to groundwater as realistic as possible, based on realistic doses and parameters from MACRO setups from the Danish Pesticide Leaching Assessment Programme. (Author)

  11. CONTRIBUTION OF INDIRECT TAXES

    Directory of Open Access Journals (Sweden)

    CHIRCULESCU MARIA FELICIA

    2015-08-01

    Full Text Available The work is based on the fact that at any time and in any society, taxation is regarded as undesirable for all taxpayers. The existence and it's manifestation is justified, because the operation of any company involves costs that must be covered by sufficient resources. Since ancient times, each state has adopted its own tax system, more or less perfected, as the state has experienced a greater or lesser economic and military power At the base of this work stays the fact that tax systems are a key factor influencing the overall efficiency of the economy. They determine the size tendency to save, invest and work, influencing the increase in production and employment, which is essential sights integral economic strategy, making tax reform an important component of economic reform. This paper aims to analyze the indirect taxes and their contribution to the public revenues in Romania, the purpose paper contains an analysis based on statistical series as indirect taxation is where tax harmonization was possible. Through analyzes, the paper aims to provide answers to the problem of the contradiction between the growing need for budgetary revenues, which entails a continuous amplification and diversification of taxation, on the one hand, and the need to stimulate economic development, on the other hand. The harmonization of indirect taxation had been achieved since this touches the free movement of goods and the freedom to supply services, not being able to say the same thing about direct taxation, which is why the European Community Treaty does not specify expressly the alignment of direct taxation, considering that direct taxation is a matter of Internal Policies that, for a country free option.

  12. Study on Leaching of Hexavalent Chromium from Hardened Concretes Using Tank Leaching Test

    OpenAIRE

    Takahashi, Shigeru; Sakai, Etsuo; Sugiyama, Takafumi

    2007-01-01

    Tank leaching tests were carried out to investigate the behavior of leaching trace elements from monolith samples. This study consists of two series, and the trace element used was hexavalent chromium. In Series I, the influence of the leachant/surface area of the specimen (L/S ratio) on the leaching amount was investigated. The leaching amount was found to increase with the amount of worked water. This shows that any L/S ratio can be selected in the tank leaching test. In Series II, th...

  13. Successful trials on pressure leaching of uranium

    International Nuclear Information System (INIS)

    Pendreigh, R.

    1978-01-01

    High pressure leaching can increase uranium extraction from some low grade ores by ten per cent, and Anglo American Corporation's eighteen months of pilot plant tests point the way to commercial application. Interest in pressure leaching of uranium has been renewed with the recent increase in uranium and gold prices and costs of reagents

  14. Optimizing conditions for an accelerated leach test

    International Nuclear Information System (INIS)

    Pietrzak, R.F.; Fuhrmann, M.; Heiser, J.; Franz, E.M.; Colombo, P.

    1988-01-01

    An accelerated leach test for low-level radioactive waste forms is being developed to provide, in a short time, data that can be extrapolated to long time periods. The approach is to provide experimental conditions that will accelerate leaching without changing the dominant release mechanism. Experimental efforts have focused on combining individual factors that have been observed to accelerate leaching. These include elevated temperature, increased leachant volume, and reduced specimen size. The response of diffusion coefficients to various acceleration factors have been evaluated and provide information on experimental parameters that need to be optimized to increase leach rates. Preliminary modeling using a diffusion mechanism (allowing for depletion) of a finite cylinder geometry indicates that during early portions of experiments (daily sampling intervals), leaching is diffusion controlled and more rapid than later in the same experiments (weekly or greater sampling intervals). For cement waste forms, this reduction in rate may be partially controlled by changes in physical structure and chemistry (sometimes related to environmental influences such as CO 2 ), but it is more likely associated with the duration of the sampling interval. By using a combination of mathematical modeling and by experimentally investigating various leach rate controlling factors, a more complete understanding of leaching processes is being developed. This, in turn, is leading to optimized accelerating conditions for a leach test

  15. Optimizing conditions for an accelerated leach test

    International Nuclear Information System (INIS)

    Pietrzak, R.F.; Fuhrmann, M.; Heiser, J.; Franz, E.M.; Colombo, P.

    1988-01-01

    An accelerated leach test for low-level radioactive waste forms is being developed to provide, in a short time, data that can be extrapolated to long time periods. The approach is to provide experimental conditions that will accelerate leaching without changing the dominant release mechanism. Experimental efforts have focused on combining individual factors that have been observed to accelerate leaching. These include elevated temperature, increased leachant volume, and reduced specimen size. The response of diffusion coefficients to various acceleration factors have been evaluated and provide information on experimental parameters that need to be optimized to increase leach rates. For example, these data show that large volumes of leachant are required when leaching portland cement waste forms at elevated temperatures because of high concentrations of dissolved species. Sr-85 leaching is particularly susceptible to suppression due to concentration effects while Cs-137 leaching is less so. Preliminary modeling using a diffusion mechanism (allowing for depletion) of a finite cylinder geometry indicates that during early portions of experiments (daily sampling intervals), leaching is diffusion controlled and more rapid than later in the same experiments (weekly or greater sampling intervals). For cement waste forms, this reduction in rate may be partially controlled by changes in physical structure and chemistry (sometimes related to environmental influences such as CO 2 ), but it is more likely associated with the duration of the sampling interval. 9 refs., 6 figs

  16. PRESERVATIVE LEACHING FROM WEATHERED CCA-TREATED WOOD

    Science.gov (United States)

    Disposal of discarded CCA-treated wood in landfills raises concerns with respect to leaching of preservative compounds. When unweathered CCA-treated wood is leached using the toxicity characteristic leaching procedure (TCLP), arsenic concentrations exceed the toxicity characteris...

  17. Leaching of heavy metals from steelmaking slags

    International Nuclear Information System (INIS)

    Gomez, J. F. P.; Pino, C. G.

    2006-01-01

    Leaching tests with EAF and Ladle slags were performed, using a flow through tests and the standard batch test DIN 38414-S4. The previous method was used to simulate the leaching behaviour of steel slags under landfill. the chemical analysis of the leachates during this period shows, in general, for both types of slag, and increase of heavy metal releases with ageing. Standard test method DIN 38414-S4 was used to evaluate leachability of heavy metals by water in unprocessed slags. After more than one year of trials, slang samples submitted to these trials presented very low total leaching levels. The most extracted elements are calcium and magnesium. Nevertheless, in flow-though test, calcium and magnesium leached from solid slags are below 0.5% and all other metals below 0.1%. Leachates obtained with DIN 38414-S4 present, as expected, higher leaching values; however, these are inferior to 5% (Ca) and 1% (other elements). (Author) 12 refs

  18. Leaching behavior of solidified plastics radioactive wastes

    International Nuclear Information System (INIS)

    Yook, Chong Chul; Lee, Byung Hun; Jae, Won Mok; Kim, Kyung Eung

    1986-01-01

    It is highly needed to develope the solidification process to dispose safely the radioactive wastes increasing with the growth of the nuclear industry. The leaching mechanisms of the solidified plastic wastes were investigated and the leaching rates of the plastic wastes were also measured among the many solidification processes. In addition, the transport equation based on the diffusion or the diffusion-dissolution was compared with the empirical equation derived from the experimental data by graphical method. Consequently, leaching process of the solidified plastic wastes is quite well agreed with the mass transport theory, but it may be difficult to simulate leaching process by diffusion dissolution mechanism. But the theoretical equation could be applicable to the cumulative amount of radionuclides leached form the plastic wastes disposed into the environment. (Author)

  19. Leaching of tritium from a cement composite

    International Nuclear Information System (INIS)

    Matsuzuru, Hideo; Ito, Akihiko

    1978-10-01

    Leaching of tritium from cement composites into an aqueous phase has been studied to evaluate the safety of incorporation of the tritiated liquid waste into cement. Leaching tests were performed by the method recommended by the International Atomic Energy Agency. The Leaching fraction was measured as functions of waste-cement ratio (Wa/C), temperature of leachant and curing time. The tritium leachability of cement in the long term test follows the order: alumina cement portland cement slag cement. The fraction of tritium leached increases with increasing Wa/C and temperature and decreasing curing period. A deionized water as a leachant gives a slightly higher leachability than synthetic sea water. The amount leached of tritium from a 200 l drum size specimen was estimated on the basis of the above results. (author)

  20. Bacteria heap leaching test of a uranium ore

    International Nuclear Information System (INIS)

    Liu Hui; Liu Jinhui; Wu Weirong; Han Wei

    2008-01-01

    Column bioleaching test of a uranium ore was carried out. The optimum acidity, spraying intensity, spray-pause time ratio were determined. The potential, Fe and U concentrations in the leaching process were investigated. The effect of bacteria column leaching was compared with that of acid column leaching. The results show that bacteria column leaching can shorten leaching cycle, and the leaching rate of uranium increases by 9.7%. (authors)

  1. Long-term leach rates of glasses containing actual waste

    International Nuclear Information System (INIS)

    Wiley, J.R.; LeRoy, J.H.

    1979-01-01

    Leach rates of borosilicate glasses that contained actual Savannah River Plant waste were measured. Leaching was done by water and by buffer solutions of pH 4, 7, and 9. Leach rates were then determined from the amount of 137 Cs, 90 Sr, and Pu released into the leach solutions. The cumulative fractions leached were fit to a mathematical model that included leaching by diffusion and glass dissolution

  2. Long-term leach rates of glasses containing actual waste

    International Nuclear Information System (INIS)

    Wiley, J.R.; LeRoy, J.H.

    1979-01-01

    Leach rates of borosilicate glasses that contained actual Savannah River Plant waste were measured. Leaching was done by water and by buffer solutions of pH 4, 7, and 9. Leach rates were then determined from the amount of 137 Cs, 90 Sr, and plutonium released into the leach solutions. The cumulative fractions leached were fit to a mathematical model that included leaching by diffusion and glass dissolution. 5 figures, 3 tables

  3. Dynamic leaching test of personal computer components.

    Science.gov (United States)

    Li, Yadong; Richardson, Jay B; Niu, Xiaojun; Jackson, Ollie J; Laster, Jeremy D; Walker, Aaron K

    2009-11-15

    A dynamic leaching test (DLT) was developed and used to evaluate the leaching of toxic substances for electronic waste in the environment. The major components in personal computers (PCs) including motherboards, hard disc drives, floppy disc drives, and compact disc drives were tested. The tests lasted for 2 years for motherboards and 1.5 year for the disc drives. The extraction fluids for the standard toxicity characteristic leaching procedure (TCLP) and synthetic precipitation leaching procedure (SPLP) were used as the DLT leaching solutions. A total of 18 elements including Ag, Al, As, Au, Ba, Be, Cd, Cr, Cu, Fe, Ga, Ni, Pd, Pb, Sb, Se, Sn, and Zn were analyzed in the DLT leachates. Only Al, Cu, Fe, Ni, Pb, and Zn were commonly found in the DLT leachates of the PC components. Their leaching levels were much higher in TCLP extraction fluid than in SPLP extraction fluid. The toxic heavy metal Pb was found to continuously leach out of the components over the entire test periods. The cumulative amounts of Pb leached out of the motherboards in TCLP extraction fluid reached 2.0 g per motherboard over the 2-year test period, and that in SPLP extraction fluid were 75-90% less. The leaching rates or levels of Pb were largely affected by the content of galvanized steel in the PC components. The higher was the steel content, the lower the Pb leaching rate would be. The findings suggest that the obsolete PCs disposed of in landfills or discarded in the environment continuously release Pb for years when subjected to landfill leachate or rains.

  4. Cultural and wild plant species as bio indicators and phyto-remedies of PHC contaminated soils in Russia

    International Nuclear Information System (INIS)

    Breus, I.; Larionova, N.; Semenova, E.; Breus, V.

    2005-01-01

    experiments: plant seed germination degree and energy, root and seedling length and biomass. Leached chernozem was contaminated by kerosene (KS) and 1-methyl-naphthalene (1-MeN). In experiments with 1-MeN the effect of aged contamination was also studied. Then experiments in vegetation vessels upon contamination of leached chernozem by kerosene and by mixture of 1-methyl-naphthalene and tri-decane were carried out. In the vegetation experiments with kerosene the phyto-remediation effect was also studied. At the first stage plant seed germination degree and germination energy in laboratory experiments on PHC-contaminated soil were determined. Upon soil contamination with 1% of kerosene the germination of majority of plants did not decrease significantly (it was 70-100%) with the exception of amaranth (60%). Upon 5% of kerosene 19 sensitive species could be used for bio-indication (germination less than 70%), including amaranth, fescue, timothy, sedge, oats, rastoropsha, kostrez, pease, mustard, colza e.a. Upon 10 and 15% of kerosene 15 species (with germination less than 70%) were bio-indicative. On the other hand some species as flax, sunflower and certain leguminosae had germination of 70% and more even upon 10 and 15% of soil contamination by kerosene. So, for the majority of the studied plants the germination parameters can be used for bio-indication only at the high levels of soil contamination by kerosene (more than 5%). For the majority of investigated plants the decrease of seed germination energy in experiments was observed. In experiments with 1-methyl-naphthalene 9 cultural species were investigated. In comparison to kerosene 1-methyl-naphthalene was much more toxic for all plant seeds at all studied contaminant levels. The ageing of contamination significantly lowered the phyto-toxicity (in relation to plant seed germination) of leached chernozem contaminated with 1-methyl-naphthalene. In special vegetative experiments we have proved not only the indirect influence

  5. Cultural and wild plant species as bio indicators and phyto-remedies of PHC contaminated soils in Russia

    Energy Technology Data Exchange (ETDEWEB)

    Breus, I.; Larionova, N.; Semenova, E.; Breus, V. [Kazan State Univ., Dept. of Geography and Geoecology (Russian Federation)

    2005-07-01

    experiments: plant seed germination degree and energy, root and seedling length and biomass. Leached chernozem was contaminated by kerosene (KS) and 1-methyl-naphthalene (1-MeN). In experiments with 1-MeN the effect of aged contamination was also studied. Then experiments in vegetation vessels upon contamination of leached chernozem by kerosene and by mixture of 1-methyl-naphthalene and tri-decane were carried out. In the vegetation experiments with kerosene the phyto-remediation effect was also studied. At the first stage plant seed germination degree and germination energy in laboratory experiments on PHC-contaminated soil were determined. Upon soil contamination with 1% of kerosene the germination of majority of plants did not decrease significantly (it was 70-100%) with the exception of amaranth (60%). Upon 5% of kerosene 19 sensitive species could be used for bio-indication (germination less than 70%), including amaranth, fescue, timothy, sedge, oats, rastoropsha, kostrez, pease, mustard, colza e.a. Upon 10 and 15% of kerosene 15 species (with germination less than 70%) were bio-indicative. On the other hand some species as flax, sunflower and certain leguminosae had germination of 70% and more even upon 10 and 15% of soil contamination by kerosene. So, for the majority of the studied plants the germination parameters can be used for bio-indication only at the high levels of soil contamination by kerosene (more than 5%). For the majority of investigated plants the decrease of seed germination energy in experiments was observed. In experiments with 1-methyl-naphthalene 9 cultural species were investigated. In comparison to kerosene 1-methyl-naphthalene was much more toxic for all plant seeds at all studied contaminant levels. The ageing of contamination significantly lowered the phyto-toxicity (in relation to plant seed germination) of leached chernozem contaminated with 1-methyl-naphthalene. In special vegetative experiments we have proved not only the indirect influence

  6. Characterizing the Leaching Behavior of Coal Combustion Residues using the Leaching Environmental Assessment Framework (LEAF) to Inform Future Management Decisions

    Science.gov (United States)

    Abstract for presentation on Characterizing the Leaching Behavior of Coal Combustion Residues using the Leaching Environmental Assessment Framework (LEAF) to Inform Future Management Decisions. The abstract is attached.

  7. Some factors affecting agitation leach test during in-situ leaching of uranium

    International Nuclear Information System (INIS)

    Liao Wensheng; Jiang Yan; Wang Limin; Shi Zhenfeng; Zhao Qiaofu; MARMAR

    2014-01-01

    The agitation leaching test is one of the most fundamental research works in in-situ leaching of uranium. Some factors affecting the test results were analyzed including stirring, leaching time, oxidizer used in alkaline leach, washing solution, the amount and size of ore samples. The results indicate that stirring can enhance diffusion velocity. The leach time l or 2 days is suitable for the samples containing accessible uranium and low acid consumption minerals; whereas 3 or 4 days for those containing refractory ore to leach and slowly acid consuming minerals. For the oxidizer used in alkaline leach, potassium permanganate is better than hydrogen peroxide. Recovery calculated by the leach solution can be directly obtained by its uranium level and the original volume of lixiviant without analyzing and calculating the washing solution. The appropriate amount and size of ore samples for the agitation leaching test are 60 g and <1 mm. By controlling the above factors, the agitation leach test can improve the applicability of the different ore samples and give the more reliable data. (authors)

  8. Bio-fuel barometer

    International Nuclear Information System (INIS)

    2015-01-01

    After a year of doubt and decline the consumption of bio-fuel resumed a growth in 2014 in Europe: +6.1% compared to 2013, to reach 14 millions tep (Mtep) that is just below the 2012 peak. This increase was mainly due to bio-diesel. By taking into account the energy content and not the volume, the consumption of bio-diesel represented 79.7% of bio-fuel consumption in 2014, that of bio-ethanol only 19.1% and that of biogas 1%. The incorporating rate of bio-fuels in fuels used for transport were 4.6% in 2013 and 4.9% in 2014. The trend is good and the future of bio-fuel seems clearer as the European Union has set a not-so-bad limit of 7% for first generation bio-fuels in order to take into account the CASI effect. The CASI effect shows that an increase of the consumption of first generation bio-fuels (it means bio-fuels produced from food crops like rape, soy, cereals, sugar beet,...) implies in fact a global increase in greenhouse gas release that is due to a compensation phenomenon. More uncultivated lands (like forests, grasslands, bogs are turned into cultivated lands in order to compensate lands used for bio-fuel production. In most European countries the consumption of bio-diesel increased in 2014 while it was a bad year for the European industry of ethanol because ethanol prices dropped by 16 %. Oil companies are now among the most important producers of bio-diesel in Europe.

  9. Fungicidal values of bio-oils and their lignin-rich fractions obtained from wood/bark fast pyrolysis.

    Science.gov (United States)

    Mohan, Dinesh; Shi, Jenny; Nicholas, Darrel D; Pittman, Charles U; Steele, Philip H; Cooper, Jerome E

    2008-03-01

    Pine wood, pine bark, oak wood and oak bark were pyrolyzed in an auger reactor. A total of 16 bio-oils or pyrolytic oils were generated at different temperatures and residence times. Two additional pine bio-oils were produced at the National Renewable Energy Laboratory in a fluidized-bed reactor at different temperatures. All these bio-oils were fractionated to obtain lignin-rich fractions which consist mainly of phenols and neutrals. The pyrolytic lignin-rich fractions were obtained by liquid-liquid extraction. Whole bio-oils and their lignin-rich fractions were studied as potential environmentally benign wood preservatives to replace metal-based CCA and copper systems that have raised environmental concerns. Each bio-oil and several lignin-rich fractions were tested for antifungal properties. Soil block tests were conducted using one brown-rot fungus (Gloeophyllum trabeum) and one white-rot fungus (Trametes versicolor). The lignin-rich fractions showed greater fungal inhibition than whole bio-oils for a impregnation solution 10% concentration level. Water repellence tests were also performed to study wood wafer swelling behavior before and after bio-oil and lignin-rich fraction treatments. In this case, bio-oil fractions did not exhibit higher water repellency than whole bio-oils. Comparison of raw bio-oils in soil block tests, with unleached wafers, at 10% and 25% bio-oil impregnation solution concentration levels showed excellent wood preservation properties at the 25% level. The good performance of raw bio-oils at higher loading levels suggests that fractionation to generate lignin-rich fractions is unnecessary. At this more effective 25% loading level in general, the raw bio-oils performed similarly. Prevention of leaching is critically important for both raw bio-oils and their fractions to provide decay resistance. Initial tests of a polymerization chemical to prevent leaching showed some success.

  10. ESCA studies on leached glass forms

    International Nuclear Information System (INIS)

    Dawkins, B.G.

    1979-01-01

    Electron Spectroscopy for Chemical Analysis (ESCA) results for frit, obsidian, NBS standard, and Savannah River Laboratory (SRL) glass forms that have been subjected to cumulative water leachings of 36 hours show that [Na] exhibits the largest and fastest change of all the elements observed. Leaching of surface Na occurred within minutes. Surface Na depletion increased with leach time. Continuous x-ray irradiation and argon ion milling induced Na mobility, precluding semiquantitative ESCA analysis at normal operating temperatures. However, the sample stage has been equipped with a liquid nitrogen supply and alkali mobility should be eliminated in future work

  11. ALKALINE CARBONATE LEACHING PROCESS FOR URANIUM EXTRACTION

    Science.gov (United States)

    Thunaes, A.; Brown, E.A.; Rabbitts, A.T.

    1957-11-12

    A process for the leaching of uranium from high carbonate ores is presented. According to the process, the ore is leached at a temperature of about 200 deg C and a pressure of about 200 p.s.i.g. with a solution containing alkali carbonate, alkali permanganate, and bicarbonate ion, the bicarbonate ion functionlng to prevent premature formation of alkali hydroxide and consequent precipitation of a diuranate. After the leaching is complete, the uranium present is recovered by precipitation with NaOH.

  12. Column leaching from biomass combustion ashes

    DEFF Research Database (Denmark)

    Maresca, Alberto; Astrup, Thomas Fruergaard

    2015-01-01

    The utilization of biomass combustion ashes for forest soil liming and fertilizing has been addressed in literature. Though, a deep understanding of the ash chemical composition and leaching behavior is necessary to predict potential benefits and environmental risks related to this practice....... In this study, a fly ash sample from an operating Danish power plant based on wood biomass was collected, chemically characterized and investigated for its leaching release of nutrients and heavy metals. A column leaching test was employed. The strongly alkaline pH of all the collected eluates suggested...

  13. Leaching from municipal solid waste incineration residues

    Energy Technology Data Exchange (ETDEWEB)

    Hyks, J.

    2008-02-15

    Leaching of pollutants from Municipal Solid Waste Incineration (MSWI) residues has been investigated combining a range of laboratory leaching experiments with geochemical modeling. Special attention was paid to assessing the applicability of laboratory data for subsequent modeling with respect to presumed full-scale conditions; both sample pretreatment and actual influence of leaching conditions on the results of laboratory experiments were considered. It was shown that sample pretreatment may have large impact on leaching test data. In particular, a significant fraction of Pb was shown mobile during the washing of residues with water. In addition, drying of residues (i.e. slow oxidation) prior to leaching experiments increased the leaching of Cr significantly. Significant differences regarding the leaching behavior of individual elements with respect to (non)equilibrium conditions in column percolation experiments were observed in the study. As a result, three groups of elements were identified based on the predominant leaching control and the influence of (non)equilibrium on the results of the laboratory column experiments: I. Predominantly availability-controlled elements (e.g. Na, K, Cl) II. Solubility-controlled elements (e.g. Ca, S, Si, Al, Ba, and Zn) III. Complexation-controlled elements (e.g. Cu and Ni) With respect to the above groups it was suggested that results of laboratory column experiments can, with consideration, be used to estimate full-scale leaching of elements from Group I and II. However, in order to avoid large underestimations in the assessment of leaching from Group III, it is imperative to describe the time-dependent transport of dissolved organic carbon (DOC) in the tested system or to minimize the physical non-equilibrium during laboratory experiments (e.g. bigger column, slower flow velocity). Forward geochemical modeling was applied to simulate long-term release of elements from a MSWI air-pollution-control residue. Leaching of a

  14. Bacterial leaching of uranium ores - a review

    International Nuclear Information System (INIS)

    Lowson, R.T.

    1975-11-01

    The bacterial leaching of uranium ores involves the bacterially catalysed oxidation of associated pyrite to sulphuric acid and Fe 3+ by autotrophic bacteria and the leaching of the uranium by the resulting acidic, oxidising solution. Industrial application has been limited to Thiobacillus thiooxidans and Thiobacillus ferrooxidans at pH 2 to 3, and examples of these are described. The bacterial catalysis can be improved with nutrients or prevented with poisons. The kinetics of leaching are controlled by the bed depth, particle size, percolation rate, mineralogy and temperature. Current work is aimed at quantitatively defining the parameters controlling the kinetics and extending the method to alkaline conditions with other autotrophic bacteria. (author)

  15. Leaching properties of solidified TRU waste forms

    International Nuclear Information System (INIS)

    Colombo, P.; Neilson, R.M. Jr.

    1979-01-01

    Safety analysis of waste forms requires an estimate of the ability of these forms to retain activity in the disposal environment. This program of leaching tests will determine the leaching properties of TRU contaminated incinerator ash waste forms using hydraulic cement, urea--formaldehyde, bitumen, and vinyl ester--styrene as solidification agents. Three types of leaching tests will be conducted, including both static and flow rate. Five generic groundwaters will be used. Equipment and procedures are described. Experiments have been conducted to determine plate out of 239 Pu, counter efficiency, and stability of counting samples

  16. Role of Some Isolated Fungi in The Biological Leaching of Uranium From Low Grade Cretaceous Sandstone

    International Nuclear Information System (INIS)

    Ibrahim, H.A.; Morsy, A.; El-Sheikh, E.M.

    2012-01-01

    Microbiological leaching has been used as an alternative approach to conventional hydrometallurgical methods of uranium extraction. In this investigation, the biological leaching of uranium by isolated fungi from low grade sandstone was studied. Five isolates of fungi were obtained from sandstone sample. Cladosporium oxysporum and Penicilluim stoloniferum exhibited high potential in generating a variety of organic acids effective for uranium extraction. The percentages of organic acid produced by fungi were determined. By-product such as molasses was tested. The maximum dissolution of uranium was achieved at the following conditions; incubation period 6 days, pulp density 1:3 g/L, ph 3.5 and at 30 degree C. Maximum solubilization of uranium with values of 54% and 67% were achieved by Cladosporium oxysporum and Penicilluim stoloniferum, respectively. From properly prepared pregnant bio-leach liquor, the leached uranium was recovered in the form of marketable products (3UO 3 NH 3 .5H 2 O) using classical chemical technique and the product was confirmed using XRD techniques

  17. The contribution of leaching to the rapid release of nutrients and carbon in the early decay of wetland vegetation

    Science.gov (United States)

    Davis, S. E.; Childers, D.L.; Noe, G.B.

    2006-01-01

    Our goal was to quantify the coupled process of litter turnover and leaching as a source of nutrients and fixed carbon in oligotrophic, nutrient-limited wetlands. We conducted poisoned and non-poisoned incubations of leaf material from four different perennial wetland plants (Eleocharis spp., Cladium jamaicense, Rhizophora mangle and Spartina alterniflora) collected from different oligotrophic freshwater and estuarine wetland settings. Total phosphorus (TP) release from the P-limited Everglades plant species (Eleocharis spp., C. jamaicense and R. mangle) was much lower than TP release by the salt marsh plant S. alterniflora from N-limited North Inlet (SC). For most species and sampling times, total organic carbon (TOC) and TP leaching losses were much greater in poisoned than non-poisoned treatments, likely as a result of epiphytic microbial activity. Therefore, a substantial portion of the C and P leached from these wetland plant species was bio-available to microbial communities. Even the microbes associated with S. alterniflora from N-limited North Inlet showed indications of P-limitation early in the leaching process, as P was removed from the water column. Leaves of R. mangle released much more TOC per gram of litter than the other species, likely contributing to the greater waterborne [DOC] observed by others in the mangrove ecotone of Everglades National Park. Between the two freshwater Everglades plants, C. jamaicense leached nearly twice as much P than Eleocharis spp. In scaling this to the landscape level, our observed leaching losses combined with higher litter production of C. jamaicense compared to Eleocharis spp. resulted in a substantially greater P leaching from plant litter to the water column and epiphytic microbes. In conclusion, leaching of fresh plant litter can be an important autochthonous source of nutrients in freshwater and estuarine wetland ecosystems. ?? Springer 2006.

  18. Bio Engineering Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — Description/History: Chemistry and biology laboratoriesThe Bio Engineering Laboratory (BeL) is theonly full spectrum biotechnology capability within the Department...

  19. Alternative leaching processes for uranium ores

    International Nuclear Information System (INIS)

    Ring, R.J.

    1979-01-01

    Laboratory studies have been carried out to compare the extraction of uranium from Australian ores by conventional leaching in sulphuric acid with that obtained using hydrochloric acid and acidified ferric sulphate solutions. Leaching with hydrochloric acid achieved higher extractions of radium-226 but the extraction of uranium was reduced considerably. The use of acidified ferric sulphate solution reduced acid consumption by 20-40% without any detrimental effect on uranium extraction. The ferric ion, which is reduced during leaching, can be reoxidized and recycled after the addition of acid makeup. Hydrogen peroxide was found to be an effective oxidant in conventional sulphuric acid leaching. It is more expensive than alternative oxidants, but it is non-polluting, lesser quantities are required and acid consumption is reduced

  20. Leaching of potassium in a lysimeter experiment

    International Nuclear Information System (INIS)

    Gerzabek, M.H.

    1996-11-01

    Leaching of potassium was studied in the lysimeter plant in Seibersdorf/Austria (Pannonian climate). Averaged over three years, gravitational water amounted to 15.7% of the sum of precipitation (mean 485 mm) and irrigation (mean 138 mm). Differences between the four soils with respect to drainage were explained by the specific percentage of the soil skeleton. The average yearly potassium leaching ranged from 3.64 kg K/ha·yr (Dystric-Cambisol) to 22.7 kg K/ha·yr (drained Gleysol). Correlation between gravitational water volume and potassium leaching were only significant for one out of four soil types. No correlation was observed between extractable potassium in the soil profiles and potassium leaching. (author)

  1. Leaching methods for conditioned radioactive waste

    International Nuclear Information System (INIS)

    Carpentiero, R.; Bienvenu, P.; Huebra, A. G. de la; Dale, C.; Grec, D.; Gallego, C.; Rodriguez, M.; Vanderlinden, F.; Voors, P. I.; Welbergen, J.; May, R.; Fays, J.

    2005-01-01

    The physico-chemical characterization of solidified, real or simulated, radioactive waste is essential in determining their long-term stability in conditions close to that which could be encountered during disposal. The evaluation or prediction of the performance of conditioned waste passes through many suitable studies and experiments, according to a documented qualification programme. In this respect the leaching test is among the first important techniques to evaluate the feasibility of a waste form and for comparing and selecting the best waste form. So the leaching behaviour of an immobilized radioactive waste is a relevant property to be studied. The objective of the present report is to collect and describe the most representative leaching methods used in international laboratories, mainly at European level, whether standard or standard-derived. In this instance the work is a summary of the Network knowledge and applications on leaching processes in order to exchange information and scientific and technical experiences in this respect. The focus is to express all the relevant parameters of the test and its field of application. all this background is the needed starting point to clarify the similarities and shortcomings of the methods used in the EN-TRAP laboratories and, subsequently, the possible equalities or differences which can be attributed to the characteristic parameters of the different type of wastes treated. In order to comprise the significance and the effects of the parameters involved in leaching phenomena, an initial discussion on leaching mechanisms and on achievable results is made in this document. The international standardised methods are summarised as being the origin for all the network leaching procedures. This work in a preliminary way represents a comparative review ordered to introduce an unique leaching procedure to be tested in an interlaboratory comparative exercise. Further the unique method would be a quick internal reference

  2. Leaching of irradiated CANDU UO2 fuel

    International Nuclear Information System (INIS)

    Vandergraaf, T.T.; Johnson, L.H.; Lau, D.W.P.

    1980-01-01

    Irradiated fuel, leached at room temperature with distilled water and with slightly chlorinated river water, releases approx. 4% of its cesium inventory over a comparatively sort period of a few days but releases its actinides and rare earths more slowly. The matrix itself dissolves at a rate conservatively calculated to be less than approx. 2 x 10 -6 g UO 2 /cm 2 day and, with time, the leach rates of the various nuclides approach this value

  3. Leaching of nuclear power reactor wastes forms

    International Nuclear Information System (INIS)

    Endo, L.S.; Villalobos, J.P.; Miyamoto, H.

    1986-01-01

    The leaching tests for power reactor wastes carried out at IPEN/CNEN-SP are described. These waste forms consist mainly of spent resins and boric acid concentrates solidified in ordinary Portland cement. All tests were conducted according to the ISO and IAEA recommendations. 3 years leaching results are reported, determining cesium and strontium diffusivity coefficients for boric acid waste form and ion-exchange resins. (Author) [pt

  4. Method for accelerated leaching of solidified waste

    International Nuclear Information System (INIS)

    Fuhrmann, M.; Heiser, J.H.; Pietrzak, R.F.; Franz, E.M.; Colombo, P.

    1990-11-01

    An accelerated leach test method has been developed to determine the maximum leachability of solidified waste. The approach we have taken is to use a semi-dynamic leach test; that is, the leachant is sampled and replaced periodically. Parameters such as temperature, leachant volume, and specimen size are used to obtain releases that are accelerated relative to other standard leach tests and to the leaching of full-scale waste forms. The data obtained with this test can be used to model releases from waste forms, or to extrapolate from laboratory-scale to full-scale waste forms if diffusion is the dominant leaching mechanism. Diffusion can be confirmed as the leaching mechanism by using a computerized mathematical model for diffusion from a finite cylinder. We have written a computer program containing several models including diffusion to accompany this test. The program and a Users' Guide that gives screen-by-screen instructions on the use of the program are available from the authors. 14 refs., 4 figs., 1 tab

  5. Optimization of the factors that accelerate leaching

    International Nuclear Information System (INIS)

    Fuhrmann, M.; Pietrzak, R.F.; Franz, E.M.; Heiser, J.H. III; Colombo, P.

    1989-03-01

    The prediction of long-term leachability of low-level radioactive waste forms is an essential element of disposal-site performance assessment. This report describes experiments and modeling techniques used to develop an accelerated leach test that meets this need. The acceleration in leaching rates caused by the combinations of two or more factors were experimentally determined. These factors were identified earlier as being able to individually accelerate leaching. They are: elevated temperature, the size of the waste form, the ratio of the volume of leachant to the surface area of the waste form, and the frequency of replacement of the leachant. The solidification agents employed were ones that are currently used to treat low-level radioactive wastes, namely portland type I cement, bitumen, and vinyl ester-styrene. The simulated wastes, sodium sulfate, sodium tetraborate, and incinerator ash, are simplified representatives of typical low-level waste streams. Experiments determined the leaching behavior of the radionuclides of cesium (Cs-137), strontium (Sr-85), and cobalt (Co-60 or Co-57) from several different formulations of solidification agents and waste types. Leaching results were based upon radiochemical and elemental analyses of aliquots of the leachate, and on its total alkalinity and pH at various times during the experiment (up to 120 days). Solid phase analyses were carried out by Scanning/Electron Microscopy and Energy Dispersive Spectroscopy on the waste forms before and after some leaching experiments. 43 refs., 96 figs., 16 tabs

  6. Zinc Leaching from Tire Crumb Rubber

    Science.gov (United States)

    Rhodes, E. P.; Ren, J.; Mays, D. C.

    2010-12-01

    Recent estimates indicate that more than 2 billion scrap tires are currently stockpiled in the United States and approximately 280 million more tires are added annually. Various engineering applications utilize recycled tires in the form of shredded tire crumb rubber. However, the use of tire crumb rubber may have negative environmental impacts, especially when the rubber comes into contact with water. A review of the literature indicates that leaching of zinc from tire crumb rubber is the most significant water quality concern associated with using this material. Zinc is generally used in tire manufacturing, representing approximately 1.3% of the final product by mass. This study will report results from the U.S. Environmental Protection Agency’s (EPA’s) Synthetic Precipitation Leaching Procedure, batch leaching tests, and column leaching tests performed to quantify the process by which zinc leaches from tire crumb rubber into water. Results are interpreted with a first-order kinetic attachment/detachment model, implemented with the U.S. Agricultural Research Service software HYDRUS-1D, in order to determine the circumstances when zinc leaching from tire crumb rubber would be expected to comply with the applicable discharge limits. One potential application for recycled tires is replacing sand with tire crumb rubber in granular media filters used for stormwater pollution control. For this to be a viable application, the total zinc in the stormwater discharge must be below the EPA’s benchmark value of 0.117 mg/L.

  7. Leaching behavior of simulated high-level waste glass

    International Nuclear Information System (INIS)

    Kamizono, Hiroshi

    1987-03-01

    The author's work in the study on the leaching behavior of simulated high-level waste (HLW) glass were summarized. The subjects described are (1) leach rates at high temperatures, (2) effects of cracks on leach rates, (3) effects of flow rate on leach rates, and (4) an in-situ burial test in natural groundwater. In the following section, the leach rates obtained by various experiments were summarized and discussed. (author)

  8. Numerical simulation of vertical infiltration for leaching fluid in situ

    International Nuclear Information System (INIS)

    Li Jinxuan; Shi Weijun; Zhang Weimin

    1998-01-01

    Based on the analysis of movement law of leaching fluid in breaking and leaching experiment in situ, the movement of leaching fluid can be divided into two main stages in the leaching process in situ: Vertical Infiltration in unsaturation zone and horizontal runoff in saturation zone. The corresponding mathematics models are sep up, and the process of vertical infiltration of leaching fluid is numerically simulated

  9. Long-term elevated temperature leaching of solid waste forms

    International Nuclear Information System (INIS)

    Kenna, B.T.; Murphy, K.D.; Levine, H.S.

    1978-01-01

    Long-term soxhlet leaching of simulated waste glass and ceramic materials was initiated to elucidate leaching behavior of complex wasteforms. A cyclic leaching pattern was found in all systems over a 20 month period. Maxima and minima were observed in the leaching rates of all components studied with the minima coinciding. The data suggested several mechanistic features which are described, but they did not conform with reported simple leaching mechanisms

  10. Environmentally safe system for treatment of bio corrosion of ETICS

    Directory of Open Access Journals (Sweden)

    Minarovičová Katarína

    2018-01-01

    Full Text Available Effects of microorganisms on building facades are responsible for aesthetic, bio-geophysical and biogeochemical deterioration. The process of cleaning of contaminated facades involves the removal and eradication of micro flora on the surface of insulation using chemical products, killing cells and eliminating all living mass, including organic ingredients. The removal of bio corrosion coating from ETICS structure by means of chemical and preservative substances (biocides is currently the only effective and most used technology. Uncontrolled leaching of the used biocides is unacceptable. Meantime, new technology for environmentally safe maintenance of ETICS is needed. Scientists have been working on replacement the biocides currently used in facades treatment with eco-friendly biocides that have no negative effects on the environment or human beings. While the eco- treatment will be available, safe dewatering of chemicals being leached from the surface of the facade could be provided by e.g. special drain systems adjusted to the building type, use and age. The paper gives an overview of the problem in context of Slovakia and examples of leaching systems designed for new and renovated buildings.

  11. Bio digester : anaerobic methanogenesis

    NARCIS (Netherlands)

    Bullema, Marten; Hulzen, Hans; Keizer, Melvin; Pruisscher, Gerlof; Smint, Martin; Vincent, Helene

    2014-01-01

    As part of the theme 13 and 14, our group have to realize a project in the field of the renewable energy. This project consist of the design of a bio-digester for the canteen of Zernikeplein. Gert Hofstede is our client. To produce energy, a bio-digester uses the anaerobic digestion, which is made

  12. Understanding bio-economics

    NARCIS (Netherlands)

    Patel, M.K.|info:eu-repo/dai/nl/18988097X

    2008-01-01

    New plants for production of bio-based fuels, chemicals or plastics are being set up at an accelerating pace. However, this transition towards bio-based fuels, feedstocks and chemicals has not come without consequences. Increased demand has pushed up prices of key agricultural products such as maize

  13. Leaching of FGD Byproducts Using a CSTX

    Energy Technology Data Exchange (ETDEWEB)

    Kairies, C.L.; Schroeder, K.T.; Cardone, C.R.

    2005-09-01

    Leaching studies of coal utilization byproducts (CUB) are often performed to determine the compatibility of the material in a particular end-use or disposal environment. Typically, these studies are conducted using either a batch or a fixed-bed column technique. Fixed-bed columns offer the advantage of a continuous flow of effluent that provides elution profiles with changing elution volume and pH. Unfortunately, clogs can form in fixed-bed leaching columns, either because of cementitious properties of the material itself, such as is seen for fluidized bed combustion (FBC) fly ash, or because of precipitate formation, such as can occur when a high-calcium ash is subjected to sulfate-containing leachates. Also, very fine-grained materials, such as gypsum, do not provide sufficient permeability for study in a fixed-bed column. A continuous, stirred-tank extractor (CSTX) is being used as an alternative technique that can provide the elution profile of column leaching but without the low permeability problems. The CSTX has been successfully employed in the leaching of flue gas desulfurization products that would not be sufficiently permeable under traditional column leaching conditions. The results indicate that the leaching behavior depends on a number of factors, including (but not limited to) solubility and neutralization capacity of the mineral phases present, sorption properties of these phases, behavior of the solubilized material in the tank, and the type of species in solution. In addition, leaching to near-exhaustion of a wallboard produced from FGD gypsum has allowed the isolation of a highly adsorptive phase. This phase appears to be present in at least some FGD gypsums and accounts for the immobilization of trace metals such as arsenic, cobalt, lead, and mercury.

  14. Mapping ground water vulnerability to pesticide leaching with a process-based metamodel of EuroPEARL.

    Science.gov (United States)

    Tiktak, A; Boesten, J J T I; van der Linden, A M A; Vanclooster, M

    2006-01-01

    To support EU policy, indicators of pesticide leaching at the European level are required. For this reason, a metamodel of the spatially distributed European pesticide leaching model EuroPEARL was developed. EuroPEARL considers transient flow and solute transport and assumes Freundlich adsorption, first-order degradation and passive plant uptake of pesticides. Physical parameters are depth dependent while (bio)-chemical parameters are depth, temperature, and moisture dependent. The metamodel is based on an analytical expression that describes the mass fraction of pesticide leached. The metamodel ignores vertical parameter variations and assumes steady flow. The calibration dataset was generated with EuroPEARL and consisted of approximately 60,000 simulations done for 56 pesticides with different half-lives and partitioning coefficients. The target variable was the 80th percentile of the annual average leaching concentration at 1-m depth from a time series of 20 yr. The metamodel explains over 90% of the variation of the original model with only four independent spatial attributes. These parameters are available in European soil and climate databases, so that the calibrated metamodel could be applied to generate maps of the predicted leaching concentration in the European Union. Maps generated with the metamodel showed a good similarity with the maps obtained with EuroPEARL, which was confirmed by means of quantitative performance indicators.

  15. Analysis of factors affecting the effect of stope leaching

    International Nuclear Information System (INIS)

    Xie Wangnan; Dong Chunming

    2014-01-01

    The industrial test and industrial trial production of stope leaching were carried out at Taoshan orefield of Dabu deposit. The results of test and trial production showed obvious differences in leaching rate and leaching time. Compared with industrial trial production of stope leaching, the leaching rate of industrial test was higher, and leaching time was shorter. It was considered that the blasting method and liquid arrangement were the main factors affecting the leaching rate and leaching time according to analysis. So we put forward the following suggestions: the technique of deep hole slicing tight-face blasting was used to reduce the yield of lump ores, the effective liquid arrangement methods were adopted to make the lixiviant infiltrating throughout whole ore heap, and bacterial leaching was introduced. (authors)

  16. Bio-fuels

    International Nuclear Information System (INIS)

    2008-01-01

    This report presents an overview of the technologies which are currently used or presently developed for the production of bio-fuels in Europe and more particularly in France. After a brief history of this production since the beginning of the 20. century, the authors describe the support to agriculture and the influence of the Common Agricultural Policy, outline the influence of the present context of struggle against the greenhouse effect, and present the European legislative context. Data on the bio-fuels consumption in the European Union in 2006 are discussed. An overview of the evolution of the activity related to bio-fuels in France, indicating the locations of ethanol and bio-diesel production facilities, and the evolution of bio-fuel consumption, is given. The German situation is briefly presented. Production of ethanol by fermentation, the manufacturing of ETBE, the bio-diesel production from vegetable oils are discussed. Second generation bio-fuels are then presented (cellulose enzymatic processing), together with studies on thermochemical processes and available biomass resources

  17. Leaching studies on SYNROC at 950C and 2000C

    International Nuclear Information System (INIS)

    Oversby, V.M.; Ringwood, A.E.

    1982-01-01

    Crushed samples of SYNROC containing 9%, 16% and 20% of simulated high-level nuclear waste were tested for leaching behavior in distilled water at 95 0 C and 200 0 . Leach solutions were analyzed for Cs, Ca, Ba, Sr, Ti, Zr, Nd and U. Results showed that leach rates based on these elements did not change significantly as the waste loading was increased from 9 to 20%. At both temperatures, leach rates showed a decrease as leaching progressed until a plateau level was reached. Plateau leach rates, which were between 10 and 100 times lower than initial leach rates, reflect the expected long term leaching behaviour of the samples. Plateau values of leach rates for SYNROC depend on the element being leached. Highest values are found for Cs and Ba (1 to 2 x 10 -7 g/cm 2 d at 95 0 C) and lowest values for U (5 x 10 -10 g/cm 2 d at 95 0 C). Increasing leaching temperature to 200 0 C produces higher leach rates for all elements except Nd. Comparison of SYNROC leach rate data with that for PNL 76-68 glass shows that at 200 0 C the leach rate for U from SYNROC is 3000 times less than that from glass. (Auth.)

  18. Supersymmetric dark matter: Indirect detection

    International Nuclear Information System (INIS)

    Bergstroem, L.

    2000-01-01

    Dark matter detection experiments are improving to the point where they can detect or restrict the primary particle physics candidates for non baryonic dark matter. The methods for detection are usually categorized as direct, i.e., searching for signals caused by passage of dark matter particles in terrestrial detectors, or indirect. Indirect detection methods include searching for antimatter and gamma rays, in particular gamma ray lines, in cosmic rays and high-energy neutrinos from the centre of the Earth or Sun caused by accretion and annihilation of dark matter particles. A review is given of recent progress in indirect detection, both on the theoretical and experimental side

  19. The Complexity of Indirect Translation

    DEFF Research Database (Denmark)

    Wenjie, L. I.

    2017-01-01

    its complex nature, and thus determined that many facets of ITr remain to be studied. The present article will try to encompass the complexity of ITr by looking into the reasons for translating indirectly, the challenge of finding out mediating texts (MTs), indirectness in both translation...... of which have been translated and interpreted indirectly through major languages like English, will be employed as examples. Hopefully, this study will offer more insights into the nature of translation as a social activity and raise further interests in studying translation as a complex phenomenon....

  20. A simplified indirect bonding technique

    Directory of Open Access Journals (Sweden)

    Radha Katiyar

    2014-01-01

    Full Text Available With the advent of lingual orthodontics, indirect bonding technique has become an integral part of practice. It involves placement of brackets initially on the models and then their transfer to teeth with the help of transfer trays. Problems encountered with current indirect bonding techniques used are (1 the possibility of adhesive flash remaining around the base of the brackets which requires removal (2 longer time required for the adhesive to gain enough bond strength for secure tray removal. The new simplified indirect bonding technique presented here overcomes both these problems.

  1. Sulphate analysis in uranium leach iron(III) chloride solutions by inductively coupled argon plasma spectrometry

    International Nuclear Information System (INIS)

    Nirdosh, I.; Lakhani, S.; Yunus, M.Z.M.

    1993-01-01

    Inductively coupled Argon Plasma Spectrometry is used for the indirect determination of sulphate in iron(III) chloride leach solution of Elliot Lake uranium ores via addition of a known amount of barium ions and analyzing for excess of barium. The ore contains ∼ 7 wt% pyrite, FeS 2 , as the major mineral which oxidizes to generate sulphate during leaching with Fe(III). The effects of pH, the concentrations of Fe(III) and chloride ions and for presence of ethanol in the test samples on the accuracy of analysis are studied. It is found that unlike the Rhodizonate method, removal of iron(III) from or addition of ethanol to the test sample prior to analysis are not required. Linear calibration curves are obtained. (author)

  2. Leaching of gallium from gaiter granite, eastern desert, Egypt

    International Nuclear Information System (INIS)

    Zahran, M.A.; Mahmoud, KH.F.; Mahdy, M.A.; Abd El-Hamid, A.M.

    2006-01-01

    Preliminary leaching tests of gallium from some Egyptian granite rocks such as those of Gabal Gattar area was investigated by using 8 M HCl acid and sodium perchlorate as oxidant. To achieve the optimum leaching conditions, the factors affecting the leaching efficiency as the acid type and concentration, oxidant type and amount, leaching temperature, agitation time, solid / liquid ratio and the effect of grain size were studied. The complete chemical analysis of the collected samples was firstly carried out to determine the chemical features of the Gattarian granite. More than 97% of gallium content was leached when applying these optimum leaching conditions

  3. Leaching Behavior of Heavy Metals from Cement Pastes Using a Modified Toxicity Characteristic Leaching Procedure (TCLP).

    Science.gov (United States)

    Huang, Minrui; Feng, Huajun; Shen, Dongsheng; Li, Na; Chen, Yingqiang; Shentu, Jiali

    2016-03-01

    As the standard toxicity characteristic leaching procedure (TCLP) can not exhaust the acid neutralizing capacity of the cement rotary kiln co-processing solid wastes products which is particularly important for the assessment of the leaching concentrations of heavy metals. A modified TCLP was proposed. The extent of leaching of heavy metals is low using the TCLP and the leaching performance of the different metals can not be differentiated. Using the modified TCLP, however, Zn leaching was negligible during the first 180 h and then sharply increased (2.86 ± 0.18 to 3.54 ± 0.26 mg/L) as the acidity increased (pH leaching is enhanced using the modified TCLP. While Pb leached readily during the first 126 h and then leachate concentrations decreased to below the analytical detection limit. To conclude, this modified TCLP is a more suitable method for these cement rotary kiln co-processing products.

  4. Leaching of artificial radionuclide out of minerals

    International Nuclear Information System (INIS)

    Bogdanov, R.V.; Osipova, I.V.; Sergeev, A.S.

    1992-01-01

    Leaching of radionuclides induced by neutron bombardment in natural silicates and silicophosphate of rare earth elements and calcium, is studied using gamma-spectrometry. It is shown that solution of minerals under the effect of artificial subsoil water at 75 deg C is incongruent character: difference in leaching of cobalt and actinides reaches value equal to two magnitudes. Behaviour of lanthanides as analogs of transplutonium elements is of special interest. Essential role of specimen microphase composition is pointed out. The suggested methodological approach is efficient at selection of matricies for fixaton of radioactive wastes

  5. Refractory concentrate gold leaching: Cyanide vs. bromine

    Science.gov (United States)

    Dadgar, Ahmad

    1989-12-01

    Gold extraction, recovery and economics for two refractory concentrates were investigated using cyanide and bromine reagents. Gold extractions for cyanide leaching (24-48 hours) and bromine leaching (six hours) were the same and ranged from 94 to 96%. Gold recoveries from bromine pregnant solutions using carbon adsorption, ion exchange, solvent extraction, and zinc and aluminum precipitation methods were better than 99.9%. A preliminary economic analysis indicates that chemical costs for cyanidation and bromine process are 11.70 and 11.60 respectively, per tonne of calcine processed.

  6. Leaching of nuclear power reactor waste forms

    International Nuclear Information System (INIS)

    Endo, L.S.; Villalobos, J.P.; Miyamoto, H.

    1987-01-01

    The leaching tests for immobilized power reactor wastes carried out at IPEN are described. These wastes forms consist mainly of spent resins and boric acid concentrates solidified in ordinary Portland cement. All tests were conducted according to the ISO and IAEA recommendations. Three years leaching results are reported. The cesium diffuvity coefficients determined out of these results are about 1 x 10 -8 cm 2 /s for boric acid waste form and 9 x 10 -9 cm 2 /s for ion-exchange resin waste. Strontium diffusivity coefficients found are about 3 x 10 -11 cm 2 /s and 9 x 10 -11 cm 2 /s respectively. (Author) [pt

  7. Urban trees reduce nutrient leaching to groundwater.

    Science.gov (United States)

    Nidzgorski, Daniel A; Hobbie, Sarah E

    2016-07-01

    Many urban waterways suffer from excess nitrogen (N) and phosphorus (P), feeding algal blooms, which cause lower water clarity and oxygen levels, bad odor and taste, and the loss of desirable species. Nutrient movement from land to water is likely to be influenced by urban vegetation, but there are few empirical studies addressing this. In this study, we examined whether or not urban trees can reduce nutrient leaching to groundwater, an important nutrient export pathway that has received less attention than stormwater. We characterized leaching beneath 33 trees of 14 species, and seven open turfgrass areas, across three city parks in Saint Paul, Minnesota, USA. We installed lysimeters at 60 cm depth to collect soil water approximately biweekly from July 2011 through October 2013, except during winter and drought periods, measured dissolved organic carbon (C), N, and P in soil water, and modeled water fluxes using the BROOK90 hydrologic model. We also measured soil nutrient pools (bulk C and N, KCl-extractable inorganic N, Brays-P), tree tissue nutrient concentrations (C, N, and P of green leaves, leaf litter, and roots), and canopy size parameters (leaf biomass, leaf area index) to explore correlations with nutrient leaching. Trees had similar or lower N leaching than turfgrass in 2012 but higher N leaching in 2013; trees reduced P leaching compared with turfgrass in both 2012 and 2013, with lower leaching under deciduous than evergreen trees. Scaling up our measurements to an urban subwatershed of the Mississippi River (~17 400 ha, containing ~1.5 million trees), we estimated that trees reduced P leaching to groundwater by 533 kg in 2012 (0.031 kg/ha or 3.1 kg/km 2 ) and 1201 kg in 2013 (0.069 kg/ha or 6.9 kg/km 2 ). Removing these same amounts of P using stormwater infrastructure would cost $2.2 million and $5.0 million per year (2012 and 2013 removal amounts, respectively). © 2016 by the Ecological Society of America.

  8. BioProject

    Data.gov (United States)

    U.S. Department of Health & Human Services — The BioProject database provides an organizational framework to access information about research projects with links to data that have been or will be deposited...

  9. BioSentinel

    Data.gov (United States)

    National Aeronautics and Space Administration — The Advanced Exploration Systems' (AES) BioSentinel project will develop, prototype, integrate, test, and prepare for the first spaceflight mission of a broadly...

  10. BioSystems

    Data.gov (United States)

    U.S. Department of Health & Human Services — The NCBI BioSystems Database provides integrated access to biological systems and their component genes, proteins, and small molecules, as well as literature...

  11. BioHack*Kolding

    DEFF Research Database (Denmark)

    Wilde, Danielle

    Short Abstract BioHack*Kolding explores the potential of do-it-together biology to support community building in a town that lacks strong science representation, assisting participants to reflect on the bio-potential of their personal, social and political ecologies and to translate their ideas...... into action. Long Abstract Organisations that support lay people to practice bioscience alongside experts are proliferating. They enable interested people to join the global discussion on Bio Engineering by supporting them to gain the necessary knowledge and skills to do it themselves. Such organisations play...... an important role in facilitating informed debate around the biological sciences. Yet they cannot reach everyone. BioHack*Kolding asks how community-focused biology initiatives can reach people in smaller towns that lack science representation, so that they too can join the debate and ensure that its...

  12. Bio-inspired networking

    CERN Document Server

    Câmara, Daniel

    2015-01-01

    Bio-inspired techniques are based on principles, or models, of biological systems. In general, natural systems present remarkable capabilities of resilience and adaptability. In this book, we explore how bio-inspired methods can solve different problems linked to computer networks. Future networks are expected to be autonomous, scalable and adaptive. During millions of years of evolution, nature has developed a number of different systems that present these and other characteristics required for the next generation networks. Indeed, a series of bio-inspired methods have been successfully used to solve the most diverse problems linked to computer networks. This book presents some of these techniques from a theoretical and practical point of view. Discusses the key concepts of bio-inspired networking to aid you in finding efficient networking solutions Delivers examples of techniques both in theoretical concepts and practical applications Helps you apply nature's dynamic resource and task management to your co...

  13. A study of the bio-accessibility of welding fumes.

    Science.gov (United States)

    Berlinger, Balázs; Ellingsen, Dag G; Náray, Miklós; Záray, Gyula; Thomassen, Yngvar

    2008-12-01

    The respiratory bio-accessibility of a substance is the fraction that is soluble in the respiratory environment and is available for absorption. In the case of respiratory exposure the amount of absorbed substance plays a main role in the biological effects. Extensive bio-accessibility studies have always been an essential requirement for a better understanding of the biological effects of different workplace aerosols, such as welding fumes. Fumes generated using three different welding techniques, manual metal arc (MMA) welding, metal inert gas (MIG) welding, and tungsten inert gas (TIG) welding were investigated in the present study. Each technique was used for stainless steel welding. Welding fumes were collected on PVC membrane filters in batches of 114 using a multiport air sampler. Three different fluids were applied for the solubility study: deionised water and two kinds of lung fluid simulants: lung epithelial lining fluid simulant (Gamble's solution) and artificial lung lining fluid simulant (Hatch's solution). In order to obtain sufficient data to study the tendencies in solubility change with time, seven different leaching periods were used (0.5, 1, 2, 4, 8, 16, 24 h), each of them with three replicates. The effect of dissolution temperature was also studied. The total amounts of selected metals in the three different welding fumes were determined after microwave-assisted digestion with the mixture of aqua regia and hydrofluoric acid. The most obvious observation yielded by the results is that the solubility of individual metals varies greatly depending on the welding technique, the composition of the leaching fluid and leaching time. This study shows that the most reasonable choice as a media for the bio-assessment of solubility might be Hatch's solution by a dissolution time of 24 h.

  14. Life cycle assessment and residue leaching: The importance of parameter, scenario and leaching data selection

    Energy Technology Data Exchange (ETDEWEB)

    Allegrini, E., E-mail: elia@env.dtu.dk [Technical University of Denmark, Department of Environmental Engineering, Building 115, 2800 Lyngby (Denmark); Butera, S. [Technical University of Denmark, Department of Environmental Engineering, Building 115, 2800 Lyngby (Denmark); Kosson, D.S. [Vanderbilt University, Department of Civil and Environmental Engineering, Box 1831 Station B, Nashville, TN 37235 (United States); Van Zomeren, A. [Energy Research Centre of the Netherlands (ECN), Department of Environmental Risk Assessment, P.O. Box 1, 1755 ZG Petten (Netherlands); Van der Sloot, H.A. [Hans van der Sloot Consultancy, Dorpsstraat 216, 1721 BV Langedijk (Netherlands); Astrup, T.F. [Technical University of Denmark, Department of Environmental Engineering, Building 115, 2800 Lyngby (Denmark)

    2015-04-15

    Highlights: • Relevance of metal leaching in waste management system LCAs was assessed. • Toxic impacts from leaching could not be disregarded. • Uncertainty of toxicity, due to background activities, determines LCA outcomes. • Parameters such as pH and L/S affect LCA results. • Data modelling consistency and coverage within an LCA are crucial. - Abstract: Residues from industrial processes and waste management systems (WMSs) have been increasingly reutilised, leading to landfilling rate reductions and the optimisation of mineral resource utilisation in society. Life cycle assessment (LCA) is a holistic methodology allowing for the analysis of systems and products and can be applied to waste management systems to identify environmental benefits and critical aspects thereof. From an LCA perspective, residue utilisation provides benefits such as avoiding the production and depletion of primary materials, but it can lead to environmental burdens, due to the potential leaching of toxic substances. In waste LCA studies where residue utilisation is included, leaching has generally been neglected. In this study, municipal solid waste incineration bottom ash (MSWI BA) was used as a case study into three LCA scenarios having different system boundaries. The importance of data quality and parameter selection in the overall LCA results was evaluated, and an innovative method to assess metal transport into the environment was applied, in order to determine emissions to the soil and water compartments for use in an LCA. It was found that toxic impacts as a result of leaching were dominant in systems including only MSWI BA utilisation, while leaching appeared negligible in larger scenarios including the entire waste system. However, leaching could not be disregarded a priori, due to large uncertainties characterising other activities in the scenario (e.g. electricity production). Based on the analysis of relevant parameters relative to leaching, and on general results

  15. Understanding bio-economics

    OpenAIRE

    Patel, M.K.

    2008-01-01

    New plants for production of bio-based fuels, chemicals or plastics are being set up at an accelerating pace. However, this transition towards bio-based fuels, feedstocks and chemicals has not come without consequences. Increased demand has pushed up prices of key agricultural products such as maize and corn with the result that consumers - especially those in low income areas - have reacted with concern and protest. At the same time, environmental research institutes and lobby groups - and n...

  16. Engineering BioBrick vectors from BioBrick parts

    Directory of Open Access Journals (Sweden)

    Knight Thomas F

    2008-04-01

    Full Text Available Abstract Background The underlying goal of synthetic biology is to make the process of engineering biological systems easier. Recent work has focused on defining and developing standard biological parts. The technical standard that has gained the most traction in the synthetic biology community is the BioBrick standard for physical composition of genetic parts. Parts that conform to the BioBrick assembly standard are BioBrick standard biological parts. To date, over 2,000 BioBrick parts have been contributed to, and are available from, the Registry of Standard Biological Parts. Results Here we extended the same advantages of BioBrick standard biological parts to the plasmid-based vectors that are used to provide and propagate BioBrick parts. We developed a process for engineering BioBrick vectors from BioBrick parts. We designed a new set of BioBrick parts that encode many useful vector functions. We combined the new parts to make a BioBrick base vector that facilitates BioBrick vector construction. We demonstrated the utility of the process by constructing seven new BioBrick vectors. We also successfully used the resulting vectors to assemble and propagate other BioBrick standard biological parts. Conclusion We extended the principles of part reuse and standardization to BioBrick vectors. As a result, myriad new BioBrick vectors can be readily produced from all existing and newly designed BioBrick parts. We invite the synthetic biology community to (1 use the process to make and share new BioBrick vectors; (2 expand the current collection of BioBrick vector parts; and (3 characterize and improve the available collection of BioBrick vector parts.

  17. The logic of indirect speech

    Science.gov (United States)

    Pinker, Steven; Nowak, Martin A.; Lee, James J.

    2008-01-01

    When people speak, they often insinuate their intent indirectly rather than stating it as a bald proposition. Examples include sexual come-ons, veiled threats, polite requests, and concealed bribes. We propose a three-part theory of indirect speech, based on the idea that human communication involves a mixture of cooperation and conflict. First, indirect requests allow for plausible deniability, in which a cooperative listener can accept the request, but an uncooperative one cannot react adversarially to it. This intuition is supported by a game-theoretic model that predicts the costs and benefits to a speaker of direct and indirect requests. Second, language has two functions: to convey information and to negotiate the type of relationship holding between speaker and hearer (in particular, dominance, communality, or reciprocity). The emotional costs of a mismatch in the assumed relationship type can create a need for plausible deniability and, thereby, select for indirectness even when there are no tangible costs. Third, people perceive language as a digital medium, which allows a sentence to generate common knowledge, to propagate a message with high fidelity, and to serve as a reference point in coordination games. This feature makes an indirect request qualitatively different from a direct one even when the speaker and listener can infer each other's intentions with high confidence. PMID:18199841

  18. Bio-fuels barometer

    International Nuclear Information System (INIS)

    Anon.

    2010-01-01

    European Union bio-fuel use for transport reached 12 million tonnes of oil equivalent (mtoe) threshold during 2009. The slowdown in the growth of European consumption deepened again. Bio-fuel used in transport only grew by 18.7% between 2008 and 2009, as against 30.3% between 2007 and 2008 and 41.8% between 2006 and 2007. The bio-fuel incorporation rate in all fuels used by transport in the E.U. is unlikely to pass 4% in 2009. We can note that: -) the proportion of bio-fuel in the German fuels market has plummeted since 2007: from 7.3% in 2007 to 5.5% in 2009; -) France stays on course with an incorporation rate of 6.25% in 2009; -) In Spain the incorporation rate reached 3.4% in 2009 while it was 1.9% in 2008. The European bio-diesel industry has had another tough year. European production only rose by 16.6% in 2009 or by about 9 million tonnes which is well below the previous year-on-year growth rate recorded (35.7%). France is leading the production of bio-ethanol fuels in Europe with an output of 1250 million liters in 2009 while the total European production reached 3700 million litters and the world production 74000 million liters. (A.C.)

  19. ALUMINUM AND CHROMIUM LEACHING WORKSHOP WHITEPAPER

    International Nuclear Information System (INIS)

    McCabe, D; Jeff Pike, J; Bill Wilmarth, B

    2007-01-01

    A workshop was held on January 23-24, 2007 to discuss the status of processes to leach constituents from High Level Waste (HLW) sludges at the Hanford and Savannah River Sites. The objective of the workshop was to examine the needs and requirements for the HLW flowsheet for each site, discuss the status of knowledge of the leaching processes, communicate the research plans, and identify opportunities for synergy to address knowledge gaps. The purpose of leaching of non-radioactive constituents from the sludge waste is to reduce the burden of material that must be vitrified in the HLW melter systems, resulting in reduced HLW glass waste volume, reduced disposal costs, shorter process schedules, and higher facility throughput rates. The leaching process is estimated to reduce the operating life cycle of SRS by seven years and decrease the number of HLW canisters to be disposed in the Repository by 1000 [Gillam et al., 2006]. Comparably at Hanford, the aluminum and chromium leaching processes are estimated to reduce the operating life cycle of the Waste Treatment Plant by 20 years and decrease the number of canisters to the Repository by 15,000-30,000 [Gilbert, 2007]. These leaching processes will save the Department of Energy (DOE) billions of dollars in clean up and disposal costs. The primary constituents targeted for removal by leaching are aluminum and chromium. It is desirable to have some aluminum in glass to improve its durability; however, too much aluminum can increase the sludge viscosity, glass viscosity, and reduce overall process throughput. Chromium leaching is necessary to prevent formation of crystalline compounds in the glass, but is only needed at Hanford because of differences in the sludge waste chemistry at the two sites. Improving glass formulations to increase tolerance of aluminum and chromium is another approach to decrease HLW glass volume. It is likely that an optimum condition can be found by both performing leaching and improving

  20. Spent LWR fuel leach tests: Waste Isolation Safety Assessment program

    International Nuclear Information System (INIS)

    Katayama, Y.B.

    1979-04-01

    Spent light-water-reactor (LWR) fuels with burnups of 54.5, 28 and 9 MWd/kgU were leach-tested in deionized water at 25 0 C. Fuel burnup has no apparent effect on the calculated leach rates based upon the behavior of 137 Cs and 239+240 Pu. A leach test of 54.5 MWd/kgU spent fuel in synthetic sea brine showed that the cesium-based leach rate is lower in sea brine than in deionized water. A rise in the leach rate was observed after approximately 600 d of cumulative leaching. During the rise, the leach rate for all the measured radionuclides become nearly equal. Evidence suggests that exposure of new surfaces to the leachant may cause the increase. As a result, experimental work to study leaching mechanisms of spent fuel has been initiated. 22 figures

  1. Process for the leaching of AP from propellant

    Science.gov (United States)

    Shaw, G. C.; Mcintosh, M. J. (Inventor)

    1980-01-01

    A method for the recovery of ammonium perchlorate from waste solid rocket propellant is described wherein shredded particles of the propellant are leached with an aqueous leach solution containing a low concentration of surface active agent while stirring the suspension.

  2. Heap leaching of clay ish uranium ores

    International Nuclear Information System (INIS)

    Gonzalez, E.; Sedano, A.

    1973-01-01

    This paper describes an experimental facility, built near El Lobo mine. In it we study the beneficiation of low-grade uranium ore. The mineral has a great amount of clay and fines. The flow-sheet used has four steps: head leaching, ph-ajustement, ion-exchange and participation. We show, also, the most interesting results. (Author)

  3. Implementation of the Leaching Environmental Assessment ...

    Science.gov (United States)

    LEAF provides a uniform and integrated approach for evaluating leaching from solid materials (e.g., waste, treated wastes such as by solidification/stabilization, secondary materials such as blast furnace slags, energy residuals such as coal fly ash, soil, sediments, mining and mineral processing wastes). Assessment using LEAF applies a stepwise approach that considers the leaching behavior of COPCs in response to chemical and physical factors that control and material properties across a range of plausible field conditions (US EPA, 2010). The framework provides the flexibility to tailor testing to site conditions and select the extent of testing based on assessment objectives and the level of detailed information needed to support decision-making. The main focus will be to discuss the implementation of LEAF in the US and the How to Guide that has recently been completed. To present the How To Guide for the implementation of the leaching environmental assessment framework to an international audience already familiar with comparable leaching tests in use in Europe. Will be meeting with European colleagues on their interest in expanding methods to include organics.

  4. Metal leaching from refinery waste hydroprocessing catalyst.

    Science.gov (United States)

    Marafi, Meena; Rana, Mohan S

    2018-05-18

    The present study aims to develop an eco-friendly methodology for the recovery of nickel (Ni), molybdenum (Mo), and vanadium (V) from the refinery waste spent hydroprocessing catalyst. The proposed process has two stages: the first stage is to separate alumina, while the second stage involves the separation of metal compounds. The effectiveness of leaching agents, such as NH 4 OH, (NH 4 ) 2 CO 3 , and (NH 4 ) 2 S 2 O 8 , for the extraction of Mo, V, Ni, and Al from the refinery spent catalyst has been reported as a function of reagent concentration (0.5 to 2.0 molar), leaching time (1 to 6 h), and temperature (35 to 60°C). The optimal leaching conditions were achieved to obtain the maximum recovery of Mo, Ni, and V metals. The effect of the mixture of multi-ammonium salts on the metal extraction was also studied, which showed an adverse effect for Ni and V, while marginal improvement was observed for Mo leaching. The ammonium salts can form soluble metal complexes, in which stability or solubility depends on the nature of ammonium salt and the reaction conditions. The extracted metals and support can be reused to synthesize a fresh hydroprocessing catalyst. The process will reduce the refinery waste and recover the expensive metals. Therefore, the process is not only important from an environmental point of view but also vital from an economic perspective.

  5. Leaching of Plastic Additives to Marine Organisms

    NARCIS (Netherlands)

    Koelmans, A.A.; Besseling, E.; Foekema, E.M.

    2014-01-01

    It is often assumed that ingestion of microplastics by aquatic species leads to increased exposure to plastic additives. However, experimental data or model based evidence is lacking. Here we assess the potential of leaching of nonylphenol (NP) and bisphenol A (BPA) in the intestinal tracts of

  6. Gold and Silver Extraction from Leach Solutions

    OpenAIRE

    Bagdaulet K. Kenzhaliyev; Renata R. Iskhakova; Zamzagul D. Dosymbaeva; Esen N. Sulejmenov

    2014-01-01

    There has been carried out an investigation on the extraction of gold and silver from thiosulfate solutions: standard test and technological solutions of chemical and electrochemical leaching. The influence of related metals on the process of extracting gold from solution was studied. There has been conducted a comparative study of the IR spectra of solutions after the sorption of gold, silver and related metals.

  7. Leaching of transuranics observed in lysimeter experiments

    International Nuclear Information System (INIS)

    Erikson, A.; Fredriksson, L.

    1994-01-01

    A lysimeter installation, primarily designed for studies on plant uptake of transuranics from a number of Swedish soils, has been used also for studies on leaching of nuclides with drainage water from contaminated top soil layers in lysimeter vessels through 65 cm subsoil layers. Interception by ion exchanging resins simulated the nuclide transfer to a field drainage system. The study dealt with the contamination of agricultural land. The results obtained in the experiments have to be interpreted cautiously with regard to their bearing on field conditions. Also, the experimental period has been short when compared with the expected ecological half time of transuranic elements in the environment. However, the results indicate that over a first decade the leaching to drainage systems of transuranics in equilibrium with soil environments is of the same order as that of the crop uptake. The ranges assessed for leaching with an excess precipitation of 200 mm from a deposit in the plough layer to the drainage system during a decade are: for plutonium - 0.003-0.8%, for americium - 0.004-0.006% and for neptunium - 0.03-0.06%. The values for plutonium and americium are very similar except for the organic soil used which held the former nuclide very loosely bound. The leaching of neptunium seems to be ten times that for the other nuclides. It is higher on sandy soils than on organic and clay soils. (author)

  8. Duality properties of Gorringe Leach equations

    Science.gov (United States)

    Grandati, Yves; Bérard, Alain; Mohrbach, Hervé

    2009-02-01

    In the category of motions preserving the angular momentum direction, Gorringe and Leach exhibited two classes of differential equations having elliptical orbits. After enlarging slightly these classes, we show that they are related by a duality correspondence of the Arnold Vassiliev type. The specific associated conserved quantities (Laplace Runge Lenz vector and Fradkin Jauch Hill tensor) are then dual reflections of each other.

  9. COPPER LEACHING FROM WASTE ELECTRIC CABLES BY BIOHYDROMETALLURGY

    OpenAIRE

    Lambert, Fanny; Bastin, David; Gaydardzhiev, Stoyan; Léonard, Grégoire

    2015-01-01

    This study examines the leaching of copper from waste electric cables by chemical leaching and leaching catalysed by Acidithiobacillus ferrooxidans in terms of leaching kinetics and reagents consumption. Operational parameters such as the nature of the oxidant (Fe3+, O2), the initial ferric iron concentration (0-10 g/L) and the temperature (21-50°C) were identified to have an important influence on the degree of copper solubilisation. At optimal process conditions, copper extraction above 90%...

  10. Enhancements of LEACH Algorithm for Wireless Networks: A Review

    Directory of Open Access Journals (Sweden)

    M. Madheswaran

    2013-12-01

    Full Text Available Low Energy Adaptive Clustering Hierarchy (LEACH protocol is the first hierarchical cluster based routing protocol successfully used in the Wireless Sensor Networks (WSN. In this paper, various enhancements used in the original LEACH protocol are examined. The basic operations, advantages and limitations of the modified LEACH algorithms are compared to identify the research issues to be solved and to give the suggestions for the future proposed routing algorithms of wireless networks based on LEACH routing algorithm.

  11. Acid agglomeration heap leaching: present status, principle and applications

    International Nuclear Information System (INIS)

    Zeng Yijun

    2004-01-01

    For extracting valuable metal from clay-bearing acidic ores of poor permeability, agglomerated acid heap leaching appears to be the most effective method, whereas conventional leaching and general heap leaching bring about unsatisfactory recovery and poor economic returns. The present state of research work on acid agglomeration worldwide and its basic principle are discussed. The first commercial application employing acid agglomeration-heap leaching in China is also introduced

  12. Long-term lessons on pesticide leaching obtained via the Danish Pesticide Leaching Assessment Programme

    DEFF Research Database (Denmark)

    Rosenbom, Anette E.; Olsen, Preben; Plauborg, Finn

    To avoid any unacceptable influence on the environment posed by pesticides and their degradation products, all pesticides used in the European Union needs authorization. The authorization procedure includes assessing the leaching risk of both pesticides and their degradation products...

  13. Indirect Reciprocity; A Field Experiment.

    Science.gov (United States)

    van Apeldoorn, Jacobien; Schram, Arthur

    2016-01-01

    Indirect reciprocity involves cooperative acts towards strangers, either in response to their kindness to third parties (downstream) or after receiving kindness from others oneself (upstream). It is considered to be important for the evolution of cooperative behavior amongst humans. Though it has been widely studied theoretically, the empirical evidence of indirect reciprocity has thus far been limited and based solely on behavior in laboratory experiments. We provide evidence from an online environment where members can repeatedly ask and offer services to each other, free of charge. For the purpose of this study we created several new member profiles, which differ only in terms of their serving history. We then sent out a large number of service requests to different members from all over the world. We observe that a service request is more likely to be rewarded for those with a profile history of offering the service (to third parties) in the past. This provides clear evidence of (downstream) indirect reciprocity. We find no support for upstream indirect reciprocity (in this case, rewarding the service request after having previously received the service from third parties), however. Our evidence of downstream indirect reciprocity cannot be attributed to reputational effects concerning one's trustworthiness as a service user.

  14. Indirect Reciprocity under Incomplete Observation

    Science.gov (United States)

    Nakamura, Mitsuhiro; Masuda, Naoki

    2011-01-01

    Indirect reciprocity, in which individuals help others with a good reputation but not those with a bad reputation, is a mechanism for cooperation in social dilemma situations when individuals do not repeatedly interact with the same partners. In a relatively large society where indirect reciprocity is relevant, individuals may not know each other's reputation even indirectly. Previous studies investigated the situations where individuals playing the game have to determine the action possibly without knowing others' reputations. Nevertheless, the possibility that observers of the game, who generate the reputation of the interacting players, assign reputations without complete information about them has been neglected. Because an individual acts as an interacting player and as an observer on different occasions if indirect reciprocity is endogenously sustained in a society, the incompleteness of information may affect either role. We examine the game of indirect reciprocity when the reputations of players are not necessarily known to observers and to interacting players. We find that the trustful discriminator, which cooperates with good and unknown players and defects against bad players, realizes cooperative societies under seven social norms. Among the seven social norms, three of the four suspicious norms under which cooperation (defection) to unknown players leads to a good (bad) reputation enable cooperation down to a relatively small observation probability. In contrast, the three trustful norms under which both cooperation and defection to unknown players lead to a good reputation are relatively efficient. PMID:21829335

  15. Pesticide leaching through sandy and loamy fields - long-term lessons learnt from the Danish Pesticide Leaching Assessment Programme.

    Science.gov (United States)

    Rosenbom, Annette E; Olsen, Preben; Plauborg, Finn; Grant, Ruth; Juhler, René K; Brüsch, Walter; Kjær, Jeanne

    2015-06-01

    The European Union authorization procedure for pesticides includes an assessment of the leaching risk posed by pesticides and their degradation products (DP) with the aim of avoiding any unacceptable influence on groundwater. Twelve-year's results of the Danish Pesticide Leaching Assessment Programme reveal shortcomings to the procedure by having assessed leaching into groundwater of 43 pesticides applied in accordance with current regulations on agricultural fields, and 47 of their DP. Three types of leaching scenario were not fully captured by the procedure: long-term leaching of DP of pesticides applied on potato crops cultivated in sand, leaching of strongly sorbing pesticides after autumn application on loam, and leaching of various pesticides and their DP following early summer application on loam. Rapid preferential transport that bypasses the retardation of the plow layer primarily in autumn, but also during early summer, seems to dominate leaching in a number of those scenarios. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Laboratory study on leaching of a sandstone-type uranium deposit for acid in-situ leaching

    International Nuclear Information System (INIS)

    Wen Zhenqian; Yao Yixuan; Zheng Jianping; Jiang Yan; Cui Xin; Xing Yongguo; Hao Jinting; Tang Huazhang

    2013-01-01

    Ore samples were took from in-situ leaching experiment boreholes in a sandstone-type uranium deposit. Technological mineralogy study, agitating leaching and column leaching experiments were carried. The results show that the content of minerals consuming acid and deoxidized minerals is low. When sulfuric acid concentration was 1O g/L, initial uranium content was 0.0224%, and liquid-to-solid ratio was l.91, leaching rate of column leaching experiments is 89.19%, acid consumption is 8.2 kg/t ore, acid consumption is 41.88 t/tU. Acid leaching, technology is recommend for field in-situ leaching experiment, sulfuric acid concentration in confecting solution is 10 g/L, and oxidizing agent is needless during leaching process. (authors)

  17. Leaching of Titanium and Silicon from Low-Grade Titanium Slag Using Hydrochloric Acid Leaching

    Science.gov (United States)

    Zhao, Longsheng; Wang, Lina; Qi, Tao; Chen, Desheng; Zhao, Hongxin; Liu, Yahui; Wang, Weijing

    2018-05-01

    Acid-leaching behaviors of the titanium slag obtained by selective reduction of vanadium-bearing titanomagnetite concentrates were investigated. It was found that the optimal leaching of titanium and silicon were 0.7% and 1.5%, respectively. The titanium and silicon in the titanium slag were firstly dissolved in the acidic solution to form TiO2+ and silica sol, and then rapidly reprecipitated, forming hydrochloric acid (HCl) leach residue. Most of the silicon presented in the HCl leach residue as floccules-like silica gel, while most of the titanium was distributed in the nano-sized rod-like clusters with crystallite refinement and intracrystalline defects, and, as such, 94.3% of the silicon was leached from the HCl leach residue by alkaline desilication, and 96.5% of the titanium in the titanium-rich material with some rutile structure was then digested by the concentrated sulfuric acid. This provides an alternative route for the comprehensive utilization of titanium and silicon in titanium slag.

  18. Bio-processing of solid wastes and secondary resources for metal extraction – A review

    International Nuclear Information System (INIS)

    Lee, Jae-chun; Pandey, Banshi Dhar

    2012-01-01

    Highlights: ► Review focuses on bio-extraction of metals from solid wastes of industries and consumer goods. ► Bio-processing of certain effluents/wastewaters with metals is also included in brief. ► Quantity/composition of wastes are assessed, and microbes used and leaching conditions included. ► Bio-recovery using bacteria, fungi and archaea is highlighted for resource recycling. ► Process methodology/mechanism, R and D direction and scope of large scale use are briefly included. - Abstract: Metal containing wastes/byproducts of various industries, used consumer goods, and municipal waste are potential pollutants, if not treated properly. They may also be important secondary resources if processed in eco-friendly manner for secured supply of contained metals/materials. Bio-extraction of metals from such resources with microbes such as bacteria, fungi and archaea is being increasingly explored to meet the twin objectives of resource recycling and pollution mitigation. This review focuses on the bio-processing of solid wastes/byproducts of metallurgical and manufacturing industries, chemical/petrochemical plants, electroplating and tanning units, besides sewage sludge and fly ash of municipal incinerators, electronic wastes (e-wastes/PCBs), used batteries, etc. An assessment has been made to quantify the wastes generated and its compositions, microbes used, metal leaching efficiency etc. Processing of certain effluents and wastewaters comprising of metals is also included in brief. Future directions of research are highlighted.

  19. Indirect techniques in nuclear astrophysics

    International Nuclear Information System (INIS)

    Mukhamedzhanov, A.M.; Tribble, R.E.; Blokhintsev, L.D.; Cherubini, S.; Spitaleri, C.; Kroha, V.; Nunes, F.M.

    2005-01-01

    It is very difficult or often impossible to measure in the lab conditions nuclear cross sections at astrophysically relevant energies. That is why different indirect techniques are used to extract astrophysical information. In this talk different experimental possibilities to get astrophysical information using radioactive and stable beams will be addressed. 1. The asymptotic normalization coefficient (ANC) method. 2. Radiative neutron captures are determined by the spectroscopic factors (SP). A new experimental technique to determine the neutron SPs will be addressed. 3. 'Trojan Horse' is another unique indirect method, which allows one to extract the astrophysical factors for direct and resonant nuclear reactions at astrophysically relevant energies. (author)

  20. Leaching characteristics of poultry litter in first phase of multistage anaerobic digestion

    Directory of Open Access Journals (Sweden)

    Surya P Sunkavalli

    2014-05-01

    Full Text Available Poultry litter is highly biodegradable in nature. Therefore, it could be subjected to biomethanation to produce valuable biogas and bio-manure as byproducts. Some studies have been conducted along these lines in India by utilizing the poultry litter as a substrate in batch type dung digesters of KVIC and DENABANDHU models. However, these reactors have the drawbacks of high residence time (30 – 35 days, scum formation problems etc. Moreover, these batch type plants are not suitable for the treatment of large quantities of solid waste. Multistage anaerobic digestion has the potential to overcome some of the aforesaid issues. Anaerobic leaching experiments were conducted at different total solids concentration and pH using poultry litter in order to evaluate the leachate quality for a period of 7 days. The increase in Total solids (TS % from 15 to 20% show inverse effect on VFA and Alkalinity. The change in pH from 8.5 to 5.5 didn’t show much impact on VFA but there is a small impact on alkalinity. It was also observed that the leaching of the organic matter in the solid to the liquid phase is very fast and it is taking place approximately in three to four days and subsequently leachate getting saturated. Therefore, reactor set up was made in the last phase to regularly remove the water from the reactor so that higher driving force is available for leaching. The study resulted in leaching of maximum organic content in the solid to liquid within three days. DOI: http://dx.doi.org/10.3126/ije.v3i2.10516 International Journal of the Environment Vol.3(2 2014: 76-82

  1. Leaching of indaziflam applied at two rates under different rainfall situations in Florida Candler soil.

    Science.gov (United States)

    Jhala, Amit J; Ramirez, Analiza H M; Singh, Megh

    2012-03-01

    Indaziflam {N-[(1R, 2S)-2,3-dihydro-2,6-dimethyl-1H-inden-1-yl]-6-[(1RS)-1fluoroethyl]-1,3,5-triazine-2,4-diamine} is a new pre-emergence herbicide recently registered for a broad spectrum weed control in Florida citrus. Experiments were conducted to evaluate leaching of indaziflam applied at 73 and 145 g ai ha(-1) in Florida Candler soil under simulated rainfall of 5, 10, and 15 cm ha(-1). Indaziflam leached the least (12.6 ± 0.6 cm) when applied at 73 g ai ha(-1) under 5 cm ha(-1) rainfall. Indaziflam leached furthest (30.2 ± 0.9 cm) when applied at 145 g ai ha(-1) under 15 cm ha(-1) rainfall. The visual control ratings of a bio-indicator species ryegrass (Lolium multiflorum L.) was 97% at 15 cm ha(-1) rainfall when indaziflam applied at 145 g ai ha(-1) in the 26 to 30 cm horizon indicating the maximum movement and activity of indaziflam. A dose response experiment was conducted to determine the sensitivity of ryegrass to various doses of indaziflam that confirmed that application of indaziflam at 29.20 g ai ha(-1) was sufficient to prevent germination of ryegrass. There was no mortality of ryegrass plants beyond the 30 cm and the biomass of ryegrass was comparable with untreated control indicating that indaziflam did not leach beyond this distance even under 15 cm ha(-1) rainfall.

  2. BioFET-SIM

    DEFF Research Database (Denmark)

    Hediger, M. R.; Martinez, K. L.; Nygård, J.

    2013-01-01

    Biosensors based on nanowire field effect transistor (FET) have received much attention in recent years as a way to achieve ultra-sensitive and label-free sensing of molecules of biological interest. The BioFET-SIM computer model permits the analysis and interpretation of experimental sensor...... signals through its web-based interface www.biofetsim.org. The model also allows for predictions of the effects of changes in the experimental setup on the sensor signal. After an introduction to nanowire-based FET biosensors, this chapter reviews the theoretical basis of BioFET-SIM models describing both...... single and multiple charges on the analyte. Afterwards the usage of the interface and its relative command line version is briefly shown. Finally, possible applications of the BioFET-SIM model are presented. Among the possible uses of the interface, the effects on the predicted signal of pH, buffer ionic...

  3. Life cycle assessment and residue leaching: the importance of parameter, scenario and leaching data selection.

    Science.gov (United States)

    Allegrini, E; Butera, S; Kosson, D S; Van Zomeren, A; Van der Sloot, H A; Astrup, T F

    2015-04-01

    Residues from industrial processes and waste management systems (WMSs) have been increasingly reutilised, leading to landfilling rate reductions and the optimisation of mineral resource utilisation in society. Life cycle assessment (LCA) is a holistic methodology allowing for the analysis of systems and products and can be applied to waste management systems to identify environmental benefits and critical aspects thereof. From an LCA perspective, residue utilisation provides benefits such as avoiding the production and depletion of primary materials, but it can lead to environmental burdens, due to the potential leaching of toxic substances. In waste LCA studies where residue utilisation is included, leaching has generally been neglected. In this study, municipal solid waste incineration bottom ash (MSWI BA) was used as a case study into three LCA scenarios having different system boundaries. The importance of data quality and parameter selection in the overall LCA results was evaluated, and an innovative method to assess metal transport into the environment was applied, in order to determine emissions to the soil and water compartments for use in an LCA. It was found that toxic impacts as a result of leaching were dominant in systems including only MSWI BA utilisation, while leaching appeared negligible in larger scenarios including the entire waste system. However, leaching could not be disregarded a priori, due to large uncertainties characterising other activities in the scenario (e.g. electricity production). Based on the analysis of relevant parameters relative to leaching, and on general results of the study, recommendations are provided regarding the use of leaching data in LCA studies. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Leaching behaviour of strontium-90 in cement composites

    International Nuclear Information System (INIS)

    Matsuzuru, H.; Ito, A.

    1977-01-01

    The leaching of 90 Sr from a cement composite into an aqueous phase has been studied by the method recommended by IAEA. The amount leached was measured as functions of waste to cement ratio (Wa/C), salt content of waste, temperature of leachant and curing time of specimens. The leach coefficient of 90 Sr varies from ca. 6 x 10 -8 to 4 x 10 -7 cm 2 /day depending on the composition of specimen and the leaching conditions. The leachability depends on such factors as Wa/C, temperature of leachant and curing time. The Portland cement composite gives a higher leaching fraction than the slag cement one. Additives used have no significant effect on the leachability. The amount leached in deionized water as a leachant is higher than in synthetic sea water. On the basis of the results obtained, the amount of 90 Sr leached from a composite of 200 1 drum size for an extended period was estimated. (author)

  5. Pilot test of bacterial percolation leaching at Fuzhou uranium mine

    International Nuclear Information System (INIS)

    Fan Baotuan; Liu Jian; Jiang Yngqiong; Cai Chunhui; Jiang Lang; Zhou Renhua; Tong Changning; Zhang Hongli

    2006-01-01

    Total 18 t uranium ores of Fuzhou Uranium Mine packed in three or four columns in series were leached by bacterial percolation. The results show that without adding any other chemical oxidant such as sodium chlorate, the leaching rate measured by residue is 91.45%-94.48%, leaching time is 50-60 d, acid consumption is 6.17%-7.75%, and residue grade is 0.0149%-0.0208%. Compared with conventional percolation leaching process, the leaching rate is improved by 3%, leaching time is shorted by 26%, and acid consumption is saved by 34%. Accumulation pattern of ΣFe and F - in the process of leaching is discussed. Influence of F - on bacterial growth, regeneration of barren solution as well as correlative techniques are reviewed. (authors)

  6. Environmental effects of indirect subsidies

    International Nuclear Information System (INIS)

    Van Beers, C.P.; De Moor, A.P.G.; Van den Bergh, J.C.J.M.; Oosterhuis, F.H.

    2003-01-01

    The aim of the study on the title subject is to develop a transparent integrated method to determine and analyze the environmental impacts of indirect subsidies, applied in the sectors agriculture, energy, mobility, and tourism. From the results it appears that the hazardous effects of subsidies are big. Examples are milk, the regulating energy levy, and kerosene [nl

  7. Indirect searches for dark matter

    Indian Academy of Sciences (India)

    The current status of indirect searches for dark matter has been reviewed in a schematic way here. The main relevant experimental results of the recent years have been listed and the excitements and disappointments that their phenomenological interpretations in terms of almost-standard annihilating dark matter have ...

  8. Indirect methods in nuclear astrophysics

    International Nuclear Information System (INIS)

    Bertulani, C.A.; Shubhchintak; Mukhamedzhanov, A.; Kadyrov, A. S.; Kruppa, A.; Pang, D. Y.

    2016-01-01

    We discuss recent developments in indirect methods used in nuclear astrophysics to determine the capture cross sections and subsequent rates of various stellar burning processes, when it is difficult to perform the corresponding direct measurements. We discuss in brief, the basic concepts of Asymptotic Normalization Coefficients, the Trojan Horse Method, the Coulomb Dissociation Method, (d,p), and charge-exchange reactions. (paper)

  9. Indirect Reciprocity : A Field Experiment

    NARCIS (Netherlands)

    van Apeldoorn, J.; Schram, A.

    2016-01-01

    Indirect reciprocity involves cooperative acts towards strangers, either in response to their kindness to third parties (downstream) or after receiving kindness from others oneself (upstream). It is considered to be important for the evolution of cooperative behavior amongst humans. Though it has

  10. Indirect reciprocity with optional interactions.

    Science.gov (United States)

    Ghang, Whan; Nowak, Martin A

    2015-01-21

    Indirect reciprocity is a mechanism for the evolution of cooperation that is relevant for prosocial behavior among humans. Indirect reciprocity means that my behavior towards you also depends on what you have done to others. Indirect reciprocity is associated with the evolution of social intelligence and human language. Most approaches to indirect reciprocity assume obligatory interactions, but here we explore optional interactions. In any one round a game between two players is offered. A cooperator accepts a game unless the reputation of the other player indicates a defector. For a game to take place, both players must accept. In a game between a cooperator and a defector, the reputation of the defector is revealed to all players with probability Q. After a sufficiently large number of rounds the identity of all defectors is known and cooperators are no longer exploited. The crucial condition for evolution of cooperation can be written as hQB>1, where h is the average number of rounds per person and B=(b/c)-1 specifies the benefit-to-cost ratio. We analyze both stochastic and deterministic evolutionary game dynamics. We study two extensions that deal with uncertainty: hesitation and malicious gossip. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Pain and stress assessment after retinopathy of prematurity screening examination: Indirect ophthalmoscopy versus digital retinal imaging

    Directory of Open Access Journals (Sweden)

    Moral-Pumarega M

    2012-08-01

    Full Text Available Abstract Background Increasingly, neonatal clinics seek to minimize painful experiences and stress for premature infants. Fundoscopy performed with a binocular indirect ophthalmoscope is the reference examination technique for screening of retinopathy of prematurity (ROP, and it is associated with pain and stress. Wide-field digital retinal imaging is a recent technique that should be evaluated for minimizing infant pain and stress. Methods The purpose of the study was to assess and compare the impact of using a binocular indirect ophthalmoscope (BIO, or wide-field digital retinal imaging (WFDRI on pain and stress in infants undergoing ROP screening examination. This was a comparative evaluation study of two screening procedures. Ophthalmologic examinations (N = 70 were performed on 24 infants with both BIO and WFDRI. Pain assessments were performed with two specific neonatal scales (Crying, requires oxygen, increased vital signs, expression and sleeplessness, CRIES and, Premature infant pain profile, PIPP just prior to the examination, and 30 seconds, 1 hour, and 24 hours later after ending the examination. Results Changes over time were significantly different between BIO and WFDRI with both scales (PIPP score, p = .007, and CRIES score, p = .001. Median PIPP score (interquartile interval at baseline was 4 (3–5. At 30 seconds the score was 8 (6–9 for BIO and 6 (5–7 for WFDRI, respectively. The increase in PIPP score between baseline and 30 seconds was significantly lower with WFDRI (p = .006. The median increase in CRIES score from baseline to 30 seconds was 1 point lower for WFDRI than for BIO (p  Conclusions A transient short-term pain and stress response occurs with both BIO and WFDRI. Infants examined for screening of ROP with digital retinal imaging present less pain and stress at 30 seconds following completion of the exam when compared with binocular indirect ophthalmoscopy.

  12. Microbial leaching of low grade copper ores

    International Nuclear Information System (INIS)

    Rauf, A.; Ashfaq, M.

    1991-01-01

    Biotechnology is regarded as one of the most promising and revolutionary solution to various problems which are generally faced in the extraction of metals from their ores such as high energy, capital costs and environmental pollution. The paper deals with the study of low grade copper ores for their beneficiation and extraction of copper. The ores used were chalcopyrite and oxidized copper ores. Microorganisms play a vital role in the solubilization of valuable contents from ores such as copper and other metals. Studies have been conducted on the indigenous copper ores by using thiobacillus ferro oxidans and thiobacillus thio oxidans. For comparison purpose some experiments have also been conducted by chemical leaching. The results of bacterial leaching are encouraging. (author)

  13. Leaching of Electronic Waste Using Biometabolised Acids

    Institute of Scientific and Technical Information of China (English)

    M. Saidan; B. Brown; M. Valix

    2012-01-01

    The revolution in information and communication technology has brought huge technical benefits and wealth, but has created a major global problem: the generation of vast amounts of electronic waste, or e-waste through product obsolesce. The challenge in managing e-waste will be in developing sustainable recycling tech- nologies that are able to address the volume and complexity of this waste using cost effective and ecologically sen-sitive methods. In this study, the capability or microorganism metabolic acids in dissolving the metallic tractions from waste printed circuit boards was examined. Several factors were considered in the examination of the activityof the acids-including secondary reactions, solution pH, temperature and the nature of ligands in solutions (or bioacid constituents). The leaching tests were cgnducted ex-situ, using synthetic organic acids. Leaching was performed for periods of up to 6 hat 70-90 ℃ and 1000 r-min-1.

  14. Determining leach rates of monolithic waste forms

    International Nuclear Information System (INIS)

    Gilliam, T.M.; Dole, L.R.

    1986-01-01

    The ANS 16.1 Leach Procedure provides a conservative means of predicting long-term release from monolithic waste forms, offering a simple and relatively quick means of determining effective solid diffusion coefficients. As presented here, these coefficients can be used in a simple model to predict maximum release rates or be used in more complex site-specific models to predict actual site performance. For waste forms that pass the structural integrity test, this model also allows the prediction of EP-Tox leachate concentrations from these coefficients. Thus, the results of the ANS 16.1 Leach Procedure provide a powerful tool that can be used to predict the waste concentration limits in order to comply with the EP-Toxicity criteria for characteristically nonhazardous waste. 12 refs., 3 figs

  15. Leaching from denture base materials in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Lygre, H.; Solheim, E.; Gjerdet, N.R. [School of Medicine, Univ. of Bergen (Norway)

    1995-04-01

    Specimens made from denture base materials were leached in Ringer Solution and in ethanol. The specimens comprised a heat-cured product processed in two different ways and two cold-cured materials. The organic compounds leaching from the specimens to the solutions were separated, identified, and quantified by a combined gas-chromatography and gas-chromatography/mass-spectrometry technique. Additives and degradation products, possibly made by free radical reactions, were released from the denture base materials. In Ringer solution only phthalates could be quantified. In ethanol solvent, biphenyl, dibutyl phthalate, dicyclohexyl phthalate, phenyl benzoate, and phenyl salicylate were quantified. In addition, copper was found in the ethanol solvent from one of the denture base materials. The amount of leachable organic compounds varies among different materials. Processing temperature influences the initial amount of leachable compounds. 36 refs., 7 figs., 1 tab.

  16. Leaching of saltstones containing fly ash

    International Nuclear Information System (INIS)

    Barnes, M.W.; Roy, D.M.; Langton, C.A.

    1985-01-01

    Two types of fly ash were incorporated in saltstones designed for potential encapsulation of Savannah River Plant low level defense waste. These fly ashes have some cementitious properties while at the same time their presence in substitution for cement slows early hydration. Class C fly ash has a high calcium content and is considered cementitious; Class F fly ash has a low calcium content and is not classified as cementitious. Leach tests were performed and physical properties were measured for saltstones containing each class, to see the differences in the effect of the fly ashes. The four waste ions nitrate, nitrite, sodium and sulfate were shown to leach by diffusion. Effective diffusivities were determined for these ions. Data for nitrate, the most important species from the environmental point of view, are shown in Table A. Saltstones made with Class C fly ash have substantially lower leach rates than those made with Class F fly ash. The leach rates, and therefore the square roots of the effective diffusivities, have been found to be proportional to the pore surface area per unit volume (or the ratio of pore volume to pore radius), to the fraction of waste containing solution, and to the inverse of the fraction of calcium in the saltstone. Rates and diffusivities are not proportional to the water to cement ratio, because this number depends on whether the fly ash is counted as cementitious, as in Class C cement, or not cementitious, as in Class F cement. In fact the relatively small amount of calcium in Class F cement contributes to the cementitious properties overall, though not so much as Class C cement. 4 refs., 2 figs., 6 tabs

  17. Gold and Silver Extraction from Leach Solutions

    Directory of Open Access Journals (Sweden)

    Bagdaulet K. Kenzhaliyev

    2014-03-01

    Full Text Available There has been carried out an investigation on the extraction of gold and silver from thiosulfate solutions: standard test and technological solutions of chemical and electrochemical leaching. The influence of related metals on the process of extracting gold from solution was studied. There has been conducted a comparative study of the IR spectra of solutions after the sorption of gold, silver and related metals.

  18. Residues leaching from 'Factory of barren ores'

    International Nuclear Information System (INIS)

    Rakhmatov, N.; Khakimov, N.; Nazarov, Kh.M.; Barotov, A.M.

    2012-01-01

    The objective of the present work is safe management of residues from Factory of Barren Ores, their reprocessing, expenditures reduction for remediation of Istiklol city former uranium tailings. For this purpose, some experiences were adopted - Factory of Barren Ores tailing use for filling up the open pit where water with uranium content 3-5 mg/l is located. Factory of Barren Ores waste are passed through heap leaching and have some amount of uranium salts dissolved in water. Thus, we propose to dissolve uranium from Factory of Barren Ores wastes with uranium bearing water flowing out from gallery and filling up the open-pit by radioactive wastes. In so doing, uranium content flowing out from gallery will increase twice, and further, passing them through apricot's shell, as a sorbent, we will clean the water against radionuclides. Residue samples with uranium content 0,015% from Factory of Barren Ores and uranium bearing waters from gallery 1 with uranium content 0,0025 g/l were used for laboratory tests. After which, a slurry was prepared by means of residue mixing with water in ratio of solid and liquid phases (S:L) - 1:2 and 9,7 ml of sulfuric acid (Ρ=1,82) was added which corresponds consumption by H 2 SO 4 176,54 kg/t. For the first test, leaching was carried out during 4 hours at ph=1,6 at room temperature. For the second test, leaching was carried out at 60 d eg C a nd ph=1,6 during 4 hours. Slurry heating and mixing was carried out by means of magnetic mixer. The basic residue leaching indicators are provided in this article.

  19. Policy Incentives for Reducing Nitrate Leaching in Agricultural Lands: A Case Study of Irrigation and Drainage Dorudzan

    International Nuclear Information System (INIS)

    Sheikhzeinoddin, A.; Esmaeili, A.; Zibaei, M.

    2016-01-01

    Agricultural activities increasingly use water, fertilizers and pesticides, which may generate negative impacts on environment. Nowadays, nitrogen leaching from agricultural lands is a widespread global problem. Therefore, alternative land management practices such as nutrient management (rate, method and time of application), tillage operations (conservation and no-tillage), and irrigation management are routinely used to reduce non-point source pollution and improve water quality. In fact, a number of studies have illustrated the positive effects of best management practices on water and nutrient losses. The objective of this paper is to develop a bio-economic model and introducing the policy instrument for reducing nitrate from irrigation and drainage Dorudzan. We aim to identify ‘‘win–win’’ opportunities for improving farm profitability and reducing nitrate leaching.

  20. Thiosulfate leaching of gold from sulfide wastes

    Energy Technology Data Exchange (ETDEWEB)

    Block-Bolten, A.; Torma, A.E.

    1986-07-01

    The kinetics of gold extraction from lead-zinc sulfide flotation tailings by thiosulfate leachants has been investigated. The order of reaction as well as the overall reaction rate constant were, with respect to thiosulfate concentration, calculated to be n=0.75 and k=1.05 x 10/sup -6/ mol/sup 1/4/ dm/sup 5/4/ min/sup -1/. The apparent activation energy was found to be ..delta..E/sub a/=48.53 kJ and the frequency factor A=7.5 x 10/sup 2/ mol dm/sup -3/ min/sup -1/. This activation energy value suggests chemical control of the reaction mechanism. Optimum leach temperature of 50/sup 0/C was established. Gold extractions as high as 99% have been realized in two step countercurrent leachings. Change in pH throughout the leaching process was found to be an excellent indicator for the progress of the extraction. A preliminary economic evaluation of the process is given.

  1. Economic leaching at Roessing Uranium Limited

    International Nuclear Information System (INIS)

    Johnson, C.C.

    1990-01-01

    In the fourteen years that Roessing Uranium Limited has been in production, the metallurgical operations and controls on the leaching plant have envolved through four basic stages. Initially, the emphasis was placed on the achievement of consistent plant operation by overcoming severe start-up difficulties. The second stage involved the attainment of the design operating targets and also the commissioning of the ferric-leaching reactors in order to achieve a ferric ion concentration of more than 3.0 g/l. Improvements in control then became the priority, with the emphasis on consistently achieving the target concentrations of ferric ions, total iron, and terminal acidity. The latest phase has concentrated on the optimization of costs by means of adjustments to the historically established operating parameters in order to achieve large savings on consumables while maintaining the leaching efficiencies. Apart from the obvious incentive of reducing costs in an inflationary economy and a depressed uranium market, impetus for this work was given by a change in the type of ore from the open pit, which has the effect of reducing the extraction efficiency while increasing the consumption of consumable materials. These problems and their solutions are discussed in detail, and the importance to cost-effective optimization of an accurate up-to-date cost-reporting structure is stressed. 9 figs., 2 tabs

  2. Modeling of facade leaching in urban catchments

    Science.gov (United States)

    Coutu, S.; Del Giudice, D.; Rossi, L.; Barry, D. A.

    2012-12-01

    Building facades are protected from microbial attack by incorporation of biocides within them. Flow over facades leaches these biocides and transports them to the urban environment. A parsimonious water quantity/quality model applicable for engineered urban watersheds was developed to compute biocide release from facades and their transport at the urban basin scale. The model couples two lumped submodels applicable at the basin scale, and a local model of biocide leaching at the facade scale. For the facade leaching, an existing model applicable at the individual wall scale was utilized. The two lumped models describe urban hydrodynamics and leachate transport. The integrated model allows prediction of biocide concentrations in urban rivers. It was applied to a 15 km2urban hydrosystem in western Switzerland, the Vuachère river basin, to study three facade biocides (terbutryn, carbendazim, diuron). The water quality simulated by the model matched well most of the pollutographs at the outlet of the Vuachère watershed. The model was then used to estimate possible ecotoxicological impacts of facade leachates. To this end, exceedance probabilities and cumulative pollutant loads from the catchment were estimated. Results showed that the considered biocides rarely exceeded the relevant predicted no-effect concentrations for the riverine system. Despite the heterogeneities and complexity of (engineered) urban catchments, the model application demonstrated that a computationally "light" model can be employed to simulate the hydrograph and pollutograph response within them. It thus allows catchment-scale assessment of the potential ecotoxicological impact of biocides on receiving waters.

  3. Study of the sulfuric acid leaching and bacterial leaching of low grade uranium ore by orbital shaker experiment

    International Nuclear Information System (INIS)

    Li Guangyue; Liu Yulong; Wang Yongdong; Ding Dexin

    2009-01-01

    The sulphuric acid leaching and bacteria leaching by orbital shaker experiments were conducted for the low grade uranium ore from a uranium mine in Guangdong Province. The results show that, when the concentration of sulphuric acid and that of slurry were 30 g/L and 25%, respectively, the conditions were most favourable for sulphuric acid leaching and the rate of leaching reached 92.92%, that, when pH value was 1.5, inoculation amount, 10%, concentration of slurry, 10%, the conditions were most favourable for bacteria leaching and the rate of leaching reached 95.93%, that, compared with sulphuric acid leaching, bacteria leaching decreased sulphuric acid consumption by 17.2% and increased the rate of leaching by 3%, and that, under the most favourable conditions for suphuric acid leaching, if 1% natrium chlorate was added, the rate of leaching increased to 96.46%, but 10 kg of natrium chlorate was consumed for 1 ton of uranium ore. (authors)

  4. Pesticide leaching through sandy and loamy fields – Long-term lessons learnt from the Danish Pesticide Leaching Assessment Programme

    International Nuclear Information System (INIS)

    Rosenbom, Annette E.; Olsen, Preben; Plauborg, Finn; Grant, Ruth; Juhler, René K.; Brüsch, Walter; Kjær, Jeanne

    2015-01-01

    The European Union authorization procedure for pesticides includes an assessment of the leaching risk posed by pesticides and their degradation products (DP) with the aim of avoiding any unacceptable influence on groundwater. Twelve-year's results of the Danish Pesticide Leaching Assessment Programme reveal shortcomings to the procedure by having assessed leaching into groundwater of 43 pesticides applied in accordance with current regulations on agricultural fields, and 47 of their DP. Three types of leaching scenario were not fully captured by the procedure: long-term leaching of DP of pesticides applied on potato crops cultivated in sand, leaching of strongly sorbing pesticides after autumn application on loam, and leaching of various pesticides and their DP following early summer application on loam. Rapid preferential transport that bypasses the retardation of the plow layer primarily in autumn, but also during early summer, seems to dominate leaching in a number of those scenarios. - Highlights: • Field-results reveal shortcomings in the EU authorization procedure for pesticides. • The plough layer can be bypassed via preferential transport in e.g. wormholes. • Pesticides properties are decisive for leaching pattern on the sandy fields. • The hydrogeological settings control the leaching patterns on the loamy fields. • Pesticide detection frequency seems to be independent of the month of the year. - Long-term lessons learnt from the Danish Pesticide Leaching Assessment Programme reveals shortcomings in the European Union authorization procedure for pesticides

  5. BioMEMS

    CERN Document Server

    Urban, Gerald A

    2007-01-01

    Explosive growth in the field of Microsystem Technology has introduced a variety of promising products in major disciplines from microelectronics to life sciences. 'Biomes' is a discipline which focuses on microsystems for living systems. This work presents the exciting field of bio-microsystems.

  6. Bio-technologies; Biotechnologies

    Energy Technology Data Exchange (ETDEWEB)

    Grawitz, X. [Systems Bio Industries, 92 - Boulogne Billancourt (France)

    1997-12-31

    This paper is a series of transparencies which describes the measures taken by Systems Bio-Industries company to adapt its central heating plants, turbines, engines and dryers to the new French 2910 by-law about thermal efficiency and environmental impact of heating plants. The project of development of a cogeneration system in the Angouleme site is briefly described. (J.S.)

  7. Bio-Culturalism

    DEFF Research Database (Denmark)

    Grodal, Torben Kragh

    2007-01-01

    The article argues on the basis of analyses of successful films for children that not only cultural determinants but also innate determinats are important, and that film studies should combine cultural studies with cognitive theory, evolutionary theory and neuroscience, an approach that is called...... Bio-culturalism....

  8. Long-term leaching from MSWI air-pollution-control residues: Leaching characterization and modeling

    DEFF Research Database (Denmark)

    Hyks, Jiri; Astrup, Thomas; Christensen, Thomas Højlund

    2009-01-01

    Long-term leaching of Ca, Fe, Mg, K, Na, S, Al, As, Ba, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Zn, Mo, Sb, Si, Sri, Sr, Ti, V, P, Cl, and dissolved organic carbon from two different municipal solid waste incineration (MSWI) air-pollution-control residues was monitored during 24 months of column percolat......Long-term leaching of Ca, Fe, Mg, K, Na, S, Al, As, Ba, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Zn, Mo, Sb, Si, Sri, Sr, Ti, V, P, Cl, and dissolved organic carbon from two different municipal solid waste incineration (MSWI) air-pollution-control residues was monitored during 24 months of column...... percolation experiments; liquid-to-solid (L/S) ratios of 200-250 L/kg corresponding to more than 10,000 years in a conventional landfill were reached. Less than 2% of the initially present As, Cu, Pb, Zn, Cr, and Sb had leached during the Course of the experiments. Concentrations of Cd, Fe, Mg, Hg, Mn, Ni, Co......, Sn, Ti, and P were generally bellow 1 mu g/L; overall less than 1% of their mass leached. Column leaching data were further used in a two-step geochemical modeling in PHREEQC in order to (i) identify solubility controlling minerals and (ii) evaluate their interactions in a water-percolated column...

  9. Leaching of uranium and thorium from monazite: III. Leaching of radiogenic daughters

    International Nuclear Information System (INIS)

    Olander, D.; Eyal, Y.

    1990-01-01

    The solid-state diffusion model of actinide leaching developed in Part II of this series is applied to leaching of radiogenic daughters of the actinide decay chains. For an untreated natural monazite, the direct leaching component of 228 Th release is larger than that for 232 Th because of enhanced solid-state mobility for 228 Th provided by 228 Ra-recoil tracks. A significant portion of the 228 Th which appears in the leachate, however, is attributed to decay of insoluble 228 Ra which is continually released from the mineral by matrix dissolution and recoil ejection. For a monazite sample that was annealed at 800 degree C prior to leaching, the bulk of the 228 Th in solution was supplied by decay of 228 Ra rejected from the mineral matrix during annealing. The radiogenic 234 U daughter of the 238 U decay chain did not exhibit similarly enhanced leaching because the long half-life of 234 U permitted local radiation damage to be annealed out at ambient temperature prior to 234 U decay

  10. Indirect taxation in the European Union

    OpenAIRE

    Ene, Sebastian; Micuda, Dan

    2007-01-01

    Indirect taxes are levied on the production and consumption of goods and services. They influence the retail price, and hence affect patterns of trade and consumption. Indirect taxes are ultimately paid by the final consumer. Sales and turnover taxes, excise duties and tariffs are the basic indirect taxes. In contrast with direct taxes, indirect taxes are seldom progressive. The principles for the levying of these taxes will be considered before the analysis of indirect taxes.

  11. Diamond bio electronics.

    Science.gov (United States)

    Linares, Robert; Doering, Patrick; Linares, Bryant

    2009-01-01

    The use of diamond for advanced applications has been the dream of mankind for centuries. Until recently this dream has been realized only in the use of diamond for gemstones and abrasive applications where tons of diamonds are used on an annual basis. Diamond is the material system of choice for many applications, but its use has historically been limited due to the small size, high cost, and inconsistent (and typically poor) quality of available diamond materials until recently. The recent development of high quality, single crystal diamond crystal growth via the Chemical Vapor Deposition (CVD) process has allowed physcists and increasingly scientists in the life science area to think beyond these limitations and envision how diamond may be used in advanced applications ranging from quantum computing, to power generation and molecular imaging, and eventually even diamond nano-bots. Because of diamond's unique properties as a bio-compatible material, better understanding of diamond's quantum effects and a convergence of mass production, semiconductor-like fabrication process, diamond now promises a unique and powerful key to the realization of the bio-electronic devices being envisioned for the new era of medical science. The combination of robust in-the-body diamond based sensors, coupled with smart bio-functionalized diamond devices may lead to diamond being the platform of choice for bio-electronics. This generation of diamond based bio-electronic devices would contribute substantially to ushering in a paradigm shift for medical science, leading to vastly improved patient diagnosis, decrease of drug development costs and risks, and improved effectiveness of drug delivery and gene therapy programs through better timed and more customized solutions.

  12. Leaching of heavy metals from steelmaking slags

    Directory of Open Access Journals (Sweden)

    Gomes, J. F. P

    2006-12-01

    Full Text Available Leaching tests with EAF and Ladle slags were performed, using a flow through test and the standard batch test DIN 38414-S4. The previous method was used to simulate the leaching behaviour of steel slags under landfill. The chemical analysis of the leachates during this period shows, in general, for both types of slag, an increase of heavy metal releases with ageing. Standard test method DIN 38414-S4 was used to evaluate leachability of heavy metals by water in unprocessed slags. After more than one year of trials, slag samples submitted to these trials presented very low total leaching levels. The most extracted elements are calcium and magnesium. Nevertheless, in flow-through test, calcium and magnesium leached from solid slags are below 0.5% and all other metals below 0.1%. Leachates obtained with DIN 38414-S4 present, as expected, higher leaching values; however, these are inferior to 5 % (Ca and 1% (other elements.

    Este articulo contiene los resultados obtenidos en ensayos de lixiviación de escorias de acero (horno electrico y cuchara ejecutados siguiendo la metodologia de flujo dinámico así como el ensayo normalizado DIN 38414-S4. El primer ensayo intenta simular el comportamiento de lixiviación de las escorias en vertedero. Para las escorias ensayadas se han complementado los ensayos con el análisis químico de los lixiviados y se ha verificado un aumento de la liberación de metales pesados. El ensayo DIN 38414-S4 se ha utilizado para evaluar la lixiviación por agua de metales pesados, en muestras de escorias originales. Despues de un año de ensayos, se han observado niveles muy bajos de lixiviación. Los elementos mas lixiviados han sido calcio y magnesio. No obstante, en los ensayos de flujo dinámico, el calcio y el magnesio lixiviados de las escorias sólidas era menor de 0,5% y el resto de los otros metales era inferior a 0,1%. Los lixiviados obtenidos con el ensayo DIN 38414-S4 presentan, como era de esperar, valores

  13. Process for controlling calcium in a leach operation

    International Nuclear Information System (INIS)

    Habib, E.J.

    1982-01-01

    A method for controlling calcium, e.g. calcite, build-up in the leach solution of a uranium and/or related values recovery operation wherein the leach solution is flowed through a value bearing ore to dissolve the desired values. A soluble fluoride, e.g. sodium fluoride, is added to the leach solution after it has passed through the ore to thereby precipitate calcium fluoride from the leach solution and lower the calcium content of the leach solution. The soluble fluoride may be added to the leach solution before the leach solution passes through the process equipment which is used to remove the values from the leach solution or the soluble fluoride may be added after the leach solution passes through the process equipment. If added before, it is preferable to also add a carbonate/bicarbonate solution along with the soluble fluoride to prevent coprecipitation of uranyl/desired value fluoride or to redissolve coprecipitated fluoride back into the leach solution

  14. Continuous-flow leaching studies of crushed and cored SYNROC

    International Nuclear Information System (INIS)

    Coles, D.G.; Bazan, F.

    1982-01-01

    Both crushed (150- to 300- μm) and cored (1,8- mm-diam) samples of SYNROC have been leached with single-pass continuous-flow leaching equipment. Crushed samples of cesium-hollandite were also leached in a similar experiment. Temperatures used were 25 0 and 75 0 C and leachates were 0.03 N NaHCO 3 and distilled water. Leaching rates from SYNROC-C were ranked cesium > strontium greater than or equal to calcium > barium > zirconium. A comparison of leaching rates is made between crushed SYNROC, cored SYNROC, and Pacific Northwest Laboratory 76-68 glass beads. This comparison depends on how the surface areas are determined for each sample. Based on geometric surface areas for SYNROC cores and glass beads, cesium leach rates from SYNROC compare well with both sodium and neptunium leached from the glass. The other elements leached from SYNROC are lower than sodium and neptunium leached from glass. They also vary for each element, while glass shows nearly the same leach rate for both sodium and neptunium

  15. Continuous-flow leaching studies of crushed and cored SYNROC

    International Nuclear Information System (INIS)

    Coles, D.G.; Bazan, F.

    1981-01-01

    Both crushed (150 to 300 μm) and cored (1.8 mm diameter) samples of SYNROC have been leached with the single-pass continuous-flow leaching equipment. Crushed samples of Cs-hollandite were also leached in a similar experiment. Temperatures used were 25 and 75 0 C and leachates were 0.03 N NaHCO 3 and distilled water. Leaching rates from SYNROC C were ranked Cs > Sr greater than or equal to Ca > Ba > Zr. A comparison of leaching rates is made between crushed SYNROC, cored SYNROC, and PNL 76-68 glass beads. This comparison depends on how the surface areas are determined for each sample. Based on geometric surface areas for SYNROC cores and glass beads Cs leach rates from SYNROC compare well with both Na and Np leached from the glass. The other elements leached from SYNROC are lower than Na and Np leached from glass. They also vary for each element while glass shows nearly the same leach rate for both Na and Np

  16. Groundwater leaching of neutralized and untreated acid-leached uranium-mill tailings

    International Nuclear Information System (INIS)

    Gee, G.W.; Begej, C.W.; Campbell, A.C.; Sauter, N.N.; Opitz, B.E.; Sherwood, D.R.

    1981-01-01

    Tailings neutralization was examined to determine the effect of neutralization on contaminant release. Column leaching of acid extracted uranium mill tailings from Exxon Highland Mill, Wyoming, Pathfinder Gas Hills Mill, Wyoming, and the Dawn Midnite Mill, Washington, resulted in the flushing of high concentrations of salts in the first four pore volumes of leachate, followed by a steady decrease to the original groundwater salt concentrations. Neutralization decreased the concentration of salts and radionuclides leaching from the tailings and decreased the volume of solution required to return the solution to the groundwater pH and EC. Radium-226 and uranium-238 leached quickly from the tailings in the initial pore volumes of both neutralized and unneutralized tailings, and then decreased significantly. 6 figures, 5 tables

  17. Impacts of management and climate change on nitrate leaching in a forested karst area.

    Science.gov (United States)

    Dirnböck, Thomas; Kobler, Johannes; Kraus, David; Grote, Rüdiger; Kiese, Ralf

    2016-01-01

    Forest management and climate change, directly or indirectly, affect drinking water resources, both in terms of quality and quantity. In this study in the Northern Limestone Alps in Austria we have chosen model calculations (LandscapeDNDC) in order to resolve the complex long-term interactions of management and climate change and their effect on nitrogen dynamics, and the consequences for nitrate leaching from forest soils into the karst groundwater. Our study highlights the dominant role of forest management in controlling nitrate leaching. Both clear-cut and shelterwood-cut disrupt the nitrogen cycle to an extent that causes peak concentrations and high fluxes into the seepage water. While this effect is well known, our modelling approach has revealed additional positive as well as negative impacts of the expected climatic changes on nitrate leaching. First, we show that peak nitrate concentrations during post-cutting periods were elevated under all climate scenarios. The maximal effects of climatic changes on nitrate concentration peaks were 20-24 mg L(-1) in 2090 with shelterwood or clear-cut management. Second, climate change significantly decreased the cumulative nitrate losses over full forest rotation periods (by 10-20%). The stronger the expected temperature increase and precipitation decrease (in summer), the lesser were the observed nitrate losses. However, mean annual seepage water nitrate concentrations and cumulative nitrate leaching were higher under continuous forest cover management than with shelterwood-cut and clear-cut systems. Watershed management can thus be adapted to climate change by either reducing peak concentrations or long-term loads of nitrate in the karst groundwater. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Electronic Commerce and Indirect Taxation

    OpenAIRE

    Watanabe, Satoshi

    2001-01-01

    This paper considers the reason why indirect tax issues arise in the context of electronic commerce and discusses relevant issues. To do so, the paper presents a simple framework to understand and examine these issues in the international context. It also identifies common and different issues of the VAT system and the RST system. It demonstrates that an emerging solution proposed in the context of the VAT system can be affected with difficult problems that were regarded to be problems of the...

  19. Development of an accelerated leaching method for incineration bottom ash correlated to toxicity characteristic leaching protocol.

    Science.gov (United States)

    Lin, Shengxuan; Zhou, Xuedong; Ge, Liya; Ng, Sum Huan; Zhou, Xiaodong; Chang, Victor Wei-Chung

    2016-10-01

    Heavy metals and some metalloids are the most significant inorganic contaminants specified in toxicity characteristic leaching procedure (TCLP) in determining the safety of landfills or further utilization. As a consequence, a great deal of efforts had been made on the development of miniaturized analytical devices, such as Microchip Electrophoresis (ME) and μTAS for on-site testing of heavy metals and metalloids to prevent spreading of those pollutants or decrease the reutilization period of waste materials such as incineration bottom ash. However, the bottleneck lied in the long and tedious conventional TCLP that requires 18 h of leaching. Without accelerating the TCLP process, the on-site testing of the waste material leachates was impossible. In this study, therefore, a new accelerated leaching method (ALM) combining ultrasonic assisted leaching with tumbling was developed to reduce the total leaching time from 18 h to 30 min. After leaching, the concentrations of heavy metals and metalloids were determined with ICP-MS or ICP-optical emission spectroscopy. No statistical significance between ALM and TCLP was observed for most heavy metals (i.e., cobalt, manganese, mercury, molybdenum, nickel, silver, strontium, and tin) and metalloids (i.e., arsenic and selenium). For the heavy metals with statistical significance, correlation factors derived between ALM and TCLP were 0.56, 0.20, 0.037, and 0.019 for barium, cadmium, chromium, and lead, respectively. Combined with appropriate analytical techniques (e.g., ME), the ALM can be applied to rapidly prepare the incineration bottom ash samples as well as other environmental samples for on-site determination of heavy metals and metalloids. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Characterization of un-hydrated and hydrated BioAggregate™ and MTA Angelus™.

    Science.gov (United States)

    Camilleri, J; Sorrentino, F; Damidot, D

    2015-04-01

    BioAggregate™ is a novel material introduced for use as a root-end filling material. It is tricalcium silicate-based, free of aluminium and uses tantalum oxide as radiopacifier. BioAggregate contains additives to enhance the material performance. The purpose of this research was to characterize the un-hydrated and hydrated forms of BioAggregate using a combination of techniques, verify whether the additives if present affect the properties of the set material and compare these properties to those of MTA Angelus™. Un-hydrated and hydrated BioAggregate and MTA Angelus were assessed. Un-hydrated cement was tested for chemical composition, specific surface area, mineralogy and kinetics of hydration. The set material was investigated for mineralogy, microstructure and bioactivity. Scanning electron microscopy, X-ray energy dispersive spectroscopic analysis, X-ray fluorescence spectroscopy, X-ray diffraction and isothermal calorimetry were employed. The specific surface area was investigated using a gas adsorption method with nitrogen as the probe. BioAggregate was composed of tricalcium silicate, tantalum oxide, calcium phosphate and silicon dioxide and was free of aluminium. On hydration, the tricalcium silicate produced calcium silicate hydrate and calcium hydroxide. The former was deposited around the cement grains, while the latter reacted with the silicon dioxide to form additional calcium silicate hydrate. This resulted in reduction of calcium hydroxide in the aged cement. MTA Angelus reacted in a similar fashion; however, since it contained no additives, the calcium hydroxide was still present in the aged cement. Bioactivity was demonstrated by deposition of hydroxyapatite. BioAggregate exhibited a high specific surface area. Nevertheless, the reactivity determined by isothermal calorimetry appeared to be slow compared to MTA Angelus. The tantalum oxide as opposed to bismuth oxide was inert, and tantalum was not leached in solution. BioAggregate exhibited

  1. [Application of immunologic methods to the analysis of bio-leaching bacteria].

    Science.gov (United States)

    Coto, O; Fernández, A I; León, T; Rodríguez, D

    1994-09-01

    Pure cultures of Thiobacillus ferrooxidans and mixed cultures of Thiobacillus ferrooxidans and Leptospirillum ferrooxidans isolated from the Matahambre mine (Cuba) were used to fit immunodiffusion and immunoelectron microscopy to the study of iron oxidizing bacteria. The possibilities, advantages and limits of those techniques have been studied from both the identification and the serological characterization points of view. Finally, the efficiency of these methods was tested by applying them to the identification of microorganisms from acidic waters from the mine.

  2. Leaching of 210Po in human saliva from smokeless tobacco

    International Nuclear Information System (INIS)

    Syed, U.F.; Bari, A.; Husain, L.; Husain, L.

    2009-01-01

    Use of smokeless tobacco (SLT) is associated with cancer of the oral cavity. 210 Po, a known carcinogen present in SLT may leach into the saliva when the snuff is held in the mouth. Alpha emission from leached 210 Po can cause oral tissue damage, especially in the presence of non healing ulcers seen frequently in snuff users' mouth. Leaching of 210 Po from SLT in human saliva was determined for six popular US snuff brands. 210 Po was leached into human saliva for 30 min, separated radiochemically and its activity was determined by α-counting. Approximately 2-10% of 210 Po present in SLT was observed to leach. Annual exposure from leached 210 Po, based on average daily consumption of 15 g of SLT, was calculated to range from 1.1 to 3.8 Bq year -1 . (author)

  3. Continuous-flow leaching studies of crushed and cored SYNROC

    International Nuclear Information System (INIS)

    Coles, D.G.; Bazan, F.

    1980-01-01

    Both crushed (150 to 300 μm) and cored 1.8 mm diameter) samples of SYNROC have been leached with the single-pass continuous-flow leaching equipment. Crushed samples of Cs-hollandite were also leached in a similar experiment. Temperatures used were 25 0 C and 75 0 C and leachates were 0.03 N NaHCO 3 and distilled water. Leaching rates from SYNROC C were ranked Cs > Sr greater than or equal to Ca > Ba > Zr. A comparison of leaching rates is made between crushed SYNROC, cored SYNROC, and PNL 76-68 glass beads. Problems encountered when comparing the leaching rates of different waste forms are discussed

  4. Comparison of oxidants in alkaline leaching of uranium ore

    International Nuclear Information System (INIS)

    Sreenivas, T.; Rajan, K.C.; Srinivas, K.; Anand Rao, K.; Manmadha Rao, M.; Venkatakrishnan, R.R.; Padmanabhan, N.P.H.

    2007-01-01

    The uranium minerals occurring in various ore deposits consists of predominantly uranous ion (U +4 ), necessitating use of an oxidant and other lixiviants for efficient dissolution during leaching. Unlike acid leaching route, where uranium minerals dissolution could be achieved efficiently with cheaper lixiviants, processing of ores by alkaline leaching route involve expensive lixiviants and drastic leaching conditions. Alkaline leaching of uranium ores becomes economical only upon using cheaper and efficient oxidants and conservation of other reagents by their recycle. The present paper gives efficacy of various oxidants - KMnO 4 , NaOCl, Cu - NH 3 , air and oxygen, in the leaching of uranium from a low-grade dolostone hosted uranium ore of India. A comparison based on technical merits and cost of the oxidant chemicals is discussed. (author)

  5. Chlorine-assisted leaching of Key Lake uranium ore

    International Nuclear Information System (INIS)

    Haque, K.E.

    1981-04-01

    Bench-scale chlorine-assisted leach tests were conducted on the Key Lake uranium ore. Leach tests conducted at 80 0 C on a slurry containing 50% solids during 10 hours of agitation gave the maximum extraction of uranium - 96% and radium-226 - 91%. Chlorine was added at 23.0 Kg Cl 2 /tonne of ore to maintain the leach slurry pH in the range of 1.5-1.0. To obtain residue almost free of radionuclides, hydrochloric acid leaches were conducted on the first stage leach residues. The second stage leach residue still was found to contain uranium - 0.0076% and radium-226 - 200 pCi/g of solids

  6. Bio energy in Norway

    International Nuclear Information System (INIS)

    Hamnaberg, Haavard; Sidelnikova, Maria

    2011-01-01

    The main conclusion in this report is that it is possible to make available about 14 TWh bio energy in Norway than what is used today to a charge that is located less than ca. 30 oere / kWh. Almost all this potential come from the forest and requires an increase in output up to the net sustained yield. Further 5 TWh may be available in the form of biogas at a cost that is both higher and have greater uncertainty than the fixed bio energy. It is set up a cost curve based on this work, which is quoted here. This reflects only the technical costs, and does not regard wages, commissions, taxes or fees. The value of alternative uses of biomass are not considered. The cost curve must therefore not be mixed with a supply curve. (eb)

  7. Bio-fuels - biohazard

    International Nuclear Information System (INIS)

    Slovak, K.

    2008-01-01

    Politicians have a clear explanation for growing commodity prices. It is all the fault of speculators. It is easy to point the finger at an imaginary enemy. It is more difficult and from the point of view of a political career suicidal to admit one's mistakes. And there are reasons for remorse. According to studies prepared by the OECD and the World Bank bio-fuels are to be blame for high food prices. The bio-fuel boom that increases the demand for agro-commodities has been created by politicians offering generous subsidies. And so farming products do not end up on the table, but in the fuel tanks of cars in the form of additives. And their only efficiency is that they make food more expensive. The first relevant indication that environmentalist tendencies in global politics have resulted in shortages and food price increases can be found in a confidential report prepared by the World Bank. Parts of the report were leaked to the media last month. According to this information growing bio-fuel production has resulted in a food price increase by 75%. The theory that this development was caused by speculators and Chinese and Indian demand received a serious blow. And the OECD report definitely contradicted the excuse used by the politicians. According to the report one of the main reasons for growing food prices are generously subsidized bio-fuels. Their share of the increase of demand for agro-commodities in 2005 -2007 was 60% according to the study. (author)

  8. Thiosulphate leaching of gold-, silver-, copper flotation concentrates

    International Nuclear Information System (INIS)

    Samikhov, Sh.R.; Zinchenko, Z.A.

    2015-01-01

    Present article is devoted to thiosulphate leaching of gold-, silver-, copper flotation concentrates. For the purpose to improve the process of thiosulphate leaching the ore samples were calcined at temperature 600 ℃ during two hours. During the calcination process of gold-sulphide ores and concentrates the minerals pyrite and arsenopyrite oxidize which lead to opening of gold contains in them. It was defined that thiosulphate leaching can be recommended as an alternative to cyanic process.

  9. Preparation and leaching of radioactive INEL waste forms

    International Nuclear Information System (INIS)

    Schuman, R.P.; Welch, J.M.; Staples, B.A.

    1982-01-01

    The purpose of this study is to prepare and leach test ceramic and glass waste form specimens produced from actual transuranic waste sludges and high-level waste calcines, respectively. Description of wastes, specimen fabrication, leaching procedure, analysis of leachates and results are discussed. The conclusion is that radioactive waste stored at INEL can be readily incorporated in fused ceramic and glass forms. Initial leach testing results indicate that these forms show great promise for safe long-term containment of radioactive wastes

  10. Leaching of DOC, DN, and inorganic constituents from scrap tires.

    Science.gov (United States)

    Selbes, Meric; Yilmaz, Ozge; Khan, Abdul A; Karanfil, Tanju

    2015-11-01

    One concern for recycle and reuse of scrap tires is the leaching of tire constituents (organic and inorganic) with time, and their subsequent potential harmful impacts in environment. The main objective of this study was to examine the leaching of dissolved organic carbon (DOC), dissolved nitrogen (DN), and selected inorganic constituents from scrap tires. Different sizes of tire chips and crumb rubber were exposed to leaching solutions with pH's ranging from 3.0 to 10.0 for 28days. The leaching of DOC and DN were found to be higher for smaller size tire chips; however, the leaching of inorganic constituents was independent of the size. In general, basic pH conditions increased the leaching of DOC and DN, whereas acidic pH conditions led to elevated concentrations of metals. Leaching was minimal around the neutral pH values for all the monitored parameters. Analysis of the leaching rates showed that components associated with the rubbery portion of the tires (DOC, DN, zinc, calcium, magnesium, etc.) exhibited an initial rapid followed by a slow release. On the other hand, a constant rate of leaching was observed for iron and manganese, which are attributed to the metal wires present inside the tires. Although the total amounts that leached varied, the observed leaching rates were similar for all tire chip sizes and leaching solutions. Operation under neutral pH conditions, use of larger size tire chips, prewashing of tires, and removal of metal wires prior to application will reduce the impact of tire recycle and reuse. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Commercial application of bacterial heap leaching in Ganzhou uranium mine

    International Nuclear Information System (INIS)

    Liu Jian; Fan Baotuan; Meng Yunsheng; Xiao Jinfeng; Chen Sencai; Wu Jinjing; Liu Chengwu; Wu Yichang; Zeng Ruilong

    2003-01-01

    In this paper the situation of commercial application on bacterial heap leaching in Ganzhou Uranium Mine is introduced, and the construction of biomembrane oxidizing tank, regeneration and recycled utilization of barren solution are summarized. Total five heaps, 18436 t, uranium ore are leached by bacteria during the half of a year. The result is consistent with that of commercial experiment. The technology of bacterial heap leaching is more perfected

  12. Aquifer restoration techniques for in-situ leach uranium mines

    International Nuclear Information System (INIS)

    Deutsch, W.J.; Bell, N.E.; Mercer, B.W.; Serne, R.J.; Shade, J.W.; Tweeton, D.R.

    1984-02-01

    In-situ leach uranium mines and pilot-scale test facilities are currently operating in the states of Wyoming, Texas, New Mexico and Colorado. This report summarizes the technical considerations involved in restoring a leached ore zone and its aquifer to the required level. Background information is provided on the geology and geochemistry of mineralized roll-front deposits and on the leaching techniques used to extract the uranium. 13 references, 13 figures, 4 tables

  13. Extended Leach Testing of Simulated LAW Cast Stone Monoliths

    Energy Technology Data Exchange (ETDEWEB)

    Serne, R. Jeffrey [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lanigan, David C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Westsik, Joseph H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Williams, Benjamin D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jung, H. B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wang, Guohui [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-08-12

    This revision to the original report adds two longer term leach sets of data to the report and provides more discussion and graphics on how to interpret the results from long-term laboratory leach tests. The leach tests were performed at Pacific Northwest National Laboratory (PNNL) for Washington River Protection Solutions (WRPS) to evaluate the release of key constituents from monoliths of Cast Stone prepared with four simulated low-activity waste (LAW) liquid waste streams.

  14. Radiotracer investigation in gold leaching tanks

    Energy Technology Data Exchange (ETDEWEB)

    Dagadu, C.P.K., E-mail: dagadukofi@yahoo.co.uk [Ghana Atomic Energy Commission, P.O. Box LG 80, Legon, Accra (Ghana); Akaho, E.H.K.; Danso, K.A. [Ghana Atomic Energy Commission, P.O. Box LG 80, Legon, Accra (Ghana); Stegowski, Z.; Furman, L. [Faculty of Physics and Applied Computer Science, AGH-UST, 30-059 Krakow (Poland)

    2012-01-15

    Measurement and analysis of residence time distribution (RTD) is a classical method to investigate performance of chemical reactors. In the present investigation, the radioactive tracer technique was used to measure the RTD of aqueous phase in a series of gold leaching tanks at the Damang gold processing plant in Ghana. The objective of the investigation was to measure the effective volume of each tank and validate the design data after recent process intensification or revamping of the plant. I-131 was used as a radioactive tracer and was instantaneously injected into the feed stream of the first tank and monitored at the outlet of different tanks. Both sampling and online measurement methods were used to monitor the tracer concentration. The results of measurements indicated that both the methods provided identical RTD curves. The mean residence time (MRT) and effective volume of each tank was estimated. The tanks-in-series model with exchange between active and stagnant volume was used and found suitable to describe the flow structure of aqueous phase in the tanks. The estimated effective volume of the tanks and high degree of mixing in tanks could validate the design data and confirmed the expectation of the plant engineer after intensification of the process. - Highlights: Black-Right-Pointing-Pointer I-131 radioactive tracer is suitable for tracing the aqueous phase in gold ore slurry. Black-Right-Pointing-Pointer Online data collection is more convenient method for tracer monitoring in industrial process systems. Black-Right-Pointing-Pointer The tanks-in-series model with exchange between active and stagnant zones is suitable to describe the flow behavior of leaching tanks. Black-Right-Pointing-Pointer The radiotracer RTD technique could be used to validate design data after process intensification in gold leaching tanks.

  15. Probable leaching mechanisms for spent fuel

    International Nuclear Information System (INIS)

    Wang, R.; Katayama, Y.B.

    1981-01-01

    At the Pacific Northwest Laboratory, researchers in the Waste/Rock Interaction Technology Program are studying spent fuel as a possible waste form for the Office of Nuclear Waste Isolation. This paper presents probable leaching mechanisms for spent fuel and discusses current progress in identifying and understanding the leaching process. During the past year, experiments were begun to study the complex leaching mechanism of spent fuel. The initial work in this investigation was done with UO 2 , which provided the most information possible on the behavior of the spent-fuel matrix without encountering the very high radiation levels associated with spent fuel. Both single-crystal and polycrystalline UO 2 samples were used for this study, and techniques applicable to remote experimentation in a hot cell are being developed. The effects of radiation are being studied in terms of radiolysis of water and surface activation of the UO 2 . Dissolution behavior and kinetics of UO 2 were also investigated by electrochemical measurement techniques. These data will be correlated with those acquired when spent fuel is tested in a hot cell. Oxidation effects represent a major area of concern in evaluating the stability of spent fuel. Dissolution of UO 2 is greatly increased in an oxidizing solution because the dissolution is then controlled by the formation of hexavalent uranium. In solutions containing very low oxygen levels (i.e., reducing solutions), oxidation-induced dissolution may be possible via a previously oxidized surface, through exposure to air during storage, or by local oxidants such as O 2 and H 2 O 2 produced from radiolysis of water and radiation-activated UO 2 surfaces. The effects of oxidation not only increase the dissolution rate, but could lead to the disintegration of spent fuel into fine fragments

  16. Impact of weather variability on nitrate leaching

    Science.gov (United States)

    Richards, Karl; Premrov, Alina; Hackett, Richard; Coxon, Catherine

    2016-04-01

    The loss of nitrate (NO3 - N) to water via leaching and overland flow contributes to eutrophication of freshwaters, transitional and near coastal waters with agriculture contributing significantly to nitrogen (N) loading to these water. Environmental regulations, such as the Nitrates and Water Framework Directives, have increased constraints on farmers to improve N management in regions at risk of NO3--N loss to water. In addition, farmers also have to manage their systems within a changing climate as the imapcts of climate change begin to impact resulting in more frequent extreme events such as floods and droughts. The objective of this study was to investigate the link between weather volatility and the concentration of leached NO3--N spring barley. Leaching was quantified under spring barley grown on a well-drained, gravelly sandy soil using ceramic cup samplers over 6 drainage years under the same farming practices and treatments. Soil solution NO3--N concentrations under spring barley grown by conventional inversion ploughing and reduced tillage were compared to weather parameters over the period. Weather was recorded at a national Met Eireann weather station on site. Soil solution NO3--N varied significantly between years. Within individual years NO3--N concentrations varied over the drainage season, with peak concentrations generally observed in the autumn time, decreasing thereafter. Under both treatments there was a three-fold difference in mean annual soil solution NO3--N concentration over the 6 years with no change in the agronomic practices (crop type, tillage type and fertiliser input). Soil solution nitrate concentrations were significantly influenced by weather parameters such as rainfall, effective drainage and soil moisture deficit. The impact of climate change in Ireland could lead to increased NO3--N loss to water further exacerbating eutrophication of sensitive estuaries. The increased impact on eutrophication of waters, related to climatic

  17. Radiotracer investigation in gold leaching tanks

    International Nuclear Information System (INIS)

    Dagadu, C.P.K.; Akaho, E.H.K.; Danso, K.A.; Stegowski, Z.; Furman, L.

    2012-01-01

    Measurement and analysis of residence time distribution (RTD) is a classical method to investigate performance of chemical reactors. In the present investigation, the radioactive tracer technique was used to measure the RTD of aqueous phase in a series of gold leaching tanks at the Damang gold processing plant in Ghana. The objective of the investigation was to measure the effective volume of each tank and validate the design data after recent process intensification or revamping of the plant. I-131 was used as a radioactive tracer and was instantaneously injected into the feed stream of the first tank and monitored at the outlet of different tanks. Both sampling and online measurement methods were used to monitor the tracer concentration. The results of measurements indicated that both the methods provided identical RTD curves. The mean residence time (MRT) and effective volume of each tank was estimated. The tanks-in-series model with exchange between active and stagnant volume was used and found suitable to describe the flow structure of aqueous phase in the tanks. The estimated effective volume of the tanks and high degree of mixing in tanks could validate the design data and confirmed the expectation of the plant engineer after intensification of the process. - Highlights: ► I-131 radioactive tracer is suitable for tracing the aqueous phase in gold ore slurry. ► Online data collection is more convenient method for tracer monitoring in industrial process systems. ► The tanks-in-series model with exchange between active and stagnant zones is suitable to describe the flow behavior of leaching tanks. ► The radiotracer RTD technique could be used to validate design data after process intensification in gold leaching tanks.

  18. RMDF leach-field decontamination. Final report

    International Nuclear Information System (INIS)

    Carroll, J.W.; Marzec, J.M.; Stelle, A.M.

    1982-01-01

    The objective of the decontamination effort was to place the Radioactive Materials Disposal Facility (RMDF) leach field in a condition suitable for release for unrestricted use. Radioactively contaminated soil was excavated from the leach field to produce a condition of contamination as low as reasonably achievable (ALARA). The contaminated soil was boxed and shipped to an NRC-licensed burial site at Beatty, Nevada, and to the DOE burial site at Hanford, Washington. The soil excavation project successfully reduced the contamination level in the leach field to background levels, except for less than 0.6 mCi of Sr-90 and trace amounts of Cs-137 that are isolated in cracks in the bedrock. The cracks are greater than 10 ft below the surface and have been sealed with a bituminous asphalt mastic. A pathways analysis for radiation exposure to humans from the remaining radionuclides was performed, assuming intensive home gardening, and the results show that the total first year whole body dose equivalent would be about 0.1 mrem/year. This dose equivalent is a projection for the hypothetical ingestion of vegetables grown on the site. Assuming that an average adult consumes 64 kg of green leafy vegetables per year and that the entire yearly supply could be grown on the site, the amount of ingested Sr-90 and Cs-137 is calculated to be 1100 pCi/year and 200 pCi/year. This ingested quantity would produce a total first year whole body dose equivalent of 0.10 mrem, using the accepted soil-to-plant transfer factors of 0.0172 and 0.010 for Sr-90 and Cs-137, respectively. The whole body dose equivalent exposure value of 0.1 mrem/year is far below the tentative limit established by NRC of 5 mrem/year for areas released for unrestricted use

  19. Bio-ethanol

    DEFF Research Database (Denmark)

    Wenzel, Henrik

    2007-01-01

    , there is not enough biomass for 'everyone', not physically and not in terms of money to promote its use. This leads to the conclusion that any use of biomass for energy purposes will have to compare to the lost opportunity of using it for something else. In this perspective, the choice to use biomass for bio......-ethanol production will not lead to reduction but to increase in CO2 emission and fossil fuel dependency. Both first and second generation bio-ethanol suffer from a biomass-to-ethanol energy conversion efficiency as low as 30-40 %, and moreover external fossil fuels are used to run the conversion. There is only......, but they do not improve the energy balance enough for bio-ethanol to compete with alternative uses of the biomass. When using biomass to substitute fossil fuels in heat & power production, a close to 100% substitution efficiency is achieved. The best alternative for CO2 reduction and oil saving is, therefore...

  20. Solubility limits of importance to leaching

    International Nuclear Information System (INIS)

    Ogard, A.; Bentley, G.; Bryant, E.; Duffy, C.; Grisham, J.; Norris, E.; Orth, C.; Thomas, K.

    1981-01-01

    The solubilities of some radionuclides, especially rare earths and actinides, may be an important and controlling factor in leaching of waste forms. These solubilities should be measured accurately as a function of pH and not as a part of a multicomponent system. Individual solubilities should be measured as a function of temperature to determine if a kinetic effect is being observed in the data. A negative temperature coefficient of solubility for actinides and rare earths in water would have important consequences for nuclear reactor safety and for the management of nuclear wastes

  1. Leaching of TCIPP from furniture foam is rapid and substantial.

    Science.gov (United States)

    Stubbings, William A; Harrad, Stuart

    2018-02-01

    A series of laboratory experiments were conducted, in which waste furniture polyurethane foam samples containing tris (1-chloro-2-propyl) phosphate (TCIPP) were contacted with a range of leaching fluids, formulated to simulate the composition of landfill leachate. Leaching was examined under a number of different scenarios, such as: dissolved humic matter concentration, pH, and temperature, as well as the effect of agitation, and waste:leaching fluid contact duration. In addition to single batch (no replenishment of leaching fluid), serial batch (draining of leachate and replenishment with fresh leaching fluid at various time intervals) experiments were conducted. Leaching of TCIPP from PUF appears to be a first order process. Concentrations of TCIPP in leachate generated by the experiments in this study ranged from 13 mg L -1 to 130 mg L -1 . In serial batch leaching experiments, >95% of TCIPP was depleted from PUF after 168 h total contact with leaching fluid. Our experiments indicate leaching is potentially a very significant pathway of TCIPP emissions to the environment. Copyright © 2017. Published by Elsevier Ltd.

  2. Development of improved leaching techniques for vitrified radioactive waste products

    International Nuclear Information System (INIS)

    Vaswani, G.A.; Yeotikar, R.G.; Rastogi, R.C.; Sunder Rajan, N.S.

    1979-01-01

    A critical review of the current techniques for evaluating the leach resistance of vitrified radioactive wastes has been made. Inadequacy of the available leaching techniques, with respect to their adoption as standard technique on an international scale, has been brought out for the three broad catagories of aqueous attack viz., (i) simple contact with leachant at a particular temperature, (ii) once-through or recirculatory flow of leachant at variable temperatures and flow rates, and (iii) contact with freshly distilled hot water in soxhelet type of extractor. In an effort to evolve a standard leaching technique in the latter two categories of aqueous attack, development of two leaching units viz., 'Dynamic Leaching Unit' and 'Modified Soxhlet Unit' is described. Both these units offer good control and wide flexibility on the important parameters affecting leaching such as leachant temperature, flow rate of residence time of leachant and ratio of leachant volume to sample surface area. The dynamic leaching units also offers a good control and flexibility on the two additional parameters viz., the composition and pH of the leachant. In the modified soxhlet unit the composition and pH of the leachant remains near to that of distilled water. The leach rate results have been found to be reproducible. A need for framing the set of standard conditions for adoption of these units in evolution of standard leaching techniques has been indicated. (auth.)

  3. Accelerated Leach Test(s) Program. Annual report

    International Nuclear Information System (INIS)

    Dougherty, D.R.; Fuhrmann, M.; Colombo, P.

    1985-09-01

    This report summarizes the work performed for the Accelerated Leach Test(s) Program at Brookhaven National Laboratory in Fiscal Year 1985 under the sponsorship of the US Department of Energy's Low-Level Waste Management Program (LLWMP). Programmatic activities were concentrated in three areas, as listed and described in the following paragraphs. (1) A literature survey of reported leaching mechanisms, available mathematical models and factors that affect leaching of LLW forms has been compiled. Mechanisms which have been identified include diffusion, dissolution, ion exchange, corrosion and surface effects. Available mathematical models are based on diffusion as the predominant mechanism. Although numerous factors that affect leaching have been identified, they have been conveniently categorized as factors related to the entire leaching system, to the leachant or to the waste form. A report has been published on the results of this literature survey. (2) A computerized data base of LLW leaching data and mathematical models is being developed. The data are being used for model evaluation by curve fitting and statistical analysis according to standard procedures of statistical quality control. (3) Long-term tests on portland cement, bitumen and vinyl ester-styrene (VES) polymer waste forms are underway which are designed to identify and evaluate factors that accelerate leaching without changing the mechanisms. Results on the effect of temperature on leachability indicate that the leach rates of cement and VES waste forms increase with increasing temperature, whereas, the leach rate of bitumen is little affected

  4. Leach testing of Idaho Chemical Processing Plant final waste forms

    International Nuclear Information System (INIS)

    Schuman, R.P.

    1980-01-01

    A number of pellets and highly durable glasses prepared from nonradioactive-simulated high-level wasste calcines have been leach tested. The leach tests are patterned on the IAEA standard test and the proposed Materials Characterization Center tests. Most tests are made with static distilled water at 25, 70, 95, 250, and 350 0 C and in refluxing distilled water, Soxhlet, at 95 0 C. Leach rates are determined by analyzing the leachate by instrumental activation analysis or spectrochemical analysis and from weight loss. Leaches are run on glass using cast and core drilled cylinders, broken pieces and coarse ground material. Sample form has a considerable effect on leach rates; solid pieces gave higher leach rates than ground glass when expressed in g/cm 2 /day. Cesium, molybdenum and weight loss leach rates of cast glass cylinders in distilled water varied from -7 g/cm 7 /day at 25 0 C to approx. 10 -3 g/cm 2 /day at 250 0 C. The leach rates in static distilled water at 95 0 C were considerably lower than those in refluxing distilled water, Soxhlet, at the same temperature. Even at 25 0 C, sodium, cesium, and molybdenum readily leached from the porous pellets, but the pellets showed no visible attack, even at 250 0 C

  5. Microbial leaching of low grade sandstone uranium ores: column leaching studies

    International Nuclear Information System (INIS)

    Bhatti, T.M.; Malik, K.A.; Khalid, A.M.

    1991-01-01

    Microbial leaching studies on a low-grade sandstone uranium ore from Baghalchur Ore Deposits, D. G. Khan, Pakistan, containing 0.027 % U/sub 3/O/sub 8/ for extraction of uranium, were conducted in columns. Baghalchur sandstone uranium ore which is alkaline in nature, contained 5.0% calcite [CaCo/sub 3/], 2-3 % Fe/sub 2/O/sub 3/ and pyrite [FeS/sub 2/] less than 0.1 %. The ore amended with sulfur and/or sulfur slag as external energy source was found to leach with indigenous microflora mostly belonging to the genus Thiobacillus which are present in the uranium mine water. Column leaching studies revealed that when the ore was amended with elemental sulfur and irrigated with mine water (pH 3.5) 53 % U/sub 3/O/sub 8/ could be solubilized from it. However, when the natural mine water was used as such (pH 7.4) the solubilization of uranium was decreased to 41 % U/sub 3/O/sub 8/ in 90 days under similar conditions of percolation rate and temperature. The addition of (NH/sub 4/)/sub 2/SO/sub 4/ (3.0 g/L) in mine water was found to enhance the uranium leaching to 70 % U/sub 3/O/sub 8/ from the columns containing ore amended with sulfur slag. (author)

  6. Uranium leaching from phosphatic sandstone and shale of Qatrani using citrate as a new leaching reagent

    International Nuclear Information System (INIS)

    Hussein, E.M.

    1997-01-01

    Uranium is found in Qatrani area (Southwest of Cairo and North of lake Qarun) in various forms in sedimentary rocks. Two important ore materials have been chosen for studying the recovery of their uranium contents namely; the phosphatic sandstone and the carbonaceous shale. The main emphasis in this thesis is the choice of an acid that would selectively leach uranium from thesis ores while leaving calcium phosphate and carbonate minerals minerals almost completely intact. Citric acid was indeed found advantageous due primarily to its strong ability to form stable complexes with uranium over a wide range of PH values beside the possibility of controlling thr solubility of calcium-bearing compounds by adding calcium citrate. The latter is actually characterized by its ability to exist in an unionized or associated from in citric acid solutions. From the general leaching characteristics of both uranium and P 2 O 5 from Qatrani phosphatic sandstone by citric acid, it was found that uranium could be completely leached beside the possibility of realizing a differential leaching percent values vs P 2 O 5 which is generally of limited solubility. Such a low solubility of P 2 O 5 has even been completely inhibited by providing calcium citrate to the citric acid solutions in amounts sufficient to exist in an optimum ionized non-associated state. Such a provision would render the solution unable to carry any further calcium ions thus the breakdown of the phosphate mineral was hindered while uranium has completely been selectively

  7. Taoshan uranium ore fields in situ blasting heap leaching rate influence factors to investigate

    International Nuclear Information System (INIS)

    Xie Wangnan; Dong Chunming

    2014-01-01

    Taoshan ore field ore in situ blasting heap leaching out build industrial test and production process, stope leaching rate and leaching cycle is large than that, after analysis, blasting method and cloth liquid way is to affect leaching rate and leaching cycle of the main factors. This paper holds that as far as possible using stratified deep hole blasting of squeezing up ways to reduce the building pile of in-situ leaching ore block rate; Adopting effective cloth tube way, increase the leaching agent and ore contact comprehensive; Introduction of bacterial leaching, and other means to improve leaching rate, shorten production cycle, etc to solve it. (authors)

  8. Indirect detection of dark matter

    International Nuclear Information System (INIS)

    Pieri, L.

    2008-01-01

    In the Cold Dark Matter scenario, the Dark Matter particle candidate may be a Weakly Interacting Massive Particle (Wimp). Annihilation of two Wimps in local or cosmological structures would result in the production of a number of standard model particles such as photons, leptons and baryons which could be observed with the presently available or future experiments such as the Pamela or Glast satellites or the Cherenkov Telescopes. In this work we review the status-of-the-art of the theoretical and phenomenological studies about the possibility of indirect detection of signals coming from Wimp annihilation.

  9. Indirect detection of dark matter

    International Nuclear Information System (INIS)

    Carr, J; Lamanna, G; Lavalle, J

    2006-01-01

    This article is an experimental review of the status and prospects of indirect searches for dark matter. Experiments observe secondary particles such as positrons, antiprotons, antideuterons, gamma-rays and neutrinos which could originate from annihilations of dark matter particles in various locations in the galaxy. Data exist from some experiments which have been interpreted as hints of evidence for dark matter. These data and their interpretations are reviewed together with the new experiments which are planned to resolve the puzzles and make new measurements which could give unambiguous results

  10. Photo- and bio-reactivity patterns of dissolved organic matter from biomass and soil leachates and surface waters in a subtropical wetland.

    Science.gov (United States)

    Chen, Meilian; Jaffé, Rudolf

    2014-09-15

    Dissolved organic carbon (DOC) measurements and optical properties were applied to assess the photo- and bio-reactivity of dissolved organic matter (DOM) from different sources, including biomass leaching, soil leaching and surface waters in a subtropical wetland ecosystem. Samples were exposed to light and/or dark incubated through controlled laboratory experiments. Changes in DOC, ultraviolet (UV-Vis) visible absorbance, and excitation-emission matrix (EEM) fluorescence combined with parallel factor analysis (PARAFAC) were performed to assess sample degradation. Degradation experiments showed that while significant amounts of DOC were consumed during bio-incubation for biomass leachates, a higher degree of bio-recalcitrance for soil leachate and particularly surface waters was displayed. Photo- and bio-humification transformations were suggested for sawgrass, mangrove, and seagrass leachates, as compared to substantial photo-degradation and very little to almost no change after bio-incubation for the other samples. During photo-degradation in most cases the EEM-PARAFAC components displayed photo-decay as compared to a few cases which featured photo-production. In contrast during bio-incubation most EEM-PARAFAC components proved to be mostly bio-refractory although some increases and decreases in abundance were also observed. Furthermore, the sequential photo- followed by bio-degradation showed, with some exceptions, a "priming effect" of light exposure on the bio-degradation of DOM, and the combination of these two processes resulted in a DOM composition more similar to that of the natural surface water for the different sub-environments. In addition, for leachate samples there was a general enrichment of one of the EEM-PARAFAC humic-like component (Ex/Em: bio-degradation process. This study exemplifies the effectiveness of optical property and EEM-PARAFAC in the assessment of DOM reactivity and highlights the importance of the coupling of photo- and bio

  11. Combining Bio-inspired Sensing with Bio-inspired Locomotion

    DEFF Research Database (Denmark)

    Shaikh, Danish; Hallam, John; Christensen-Dalsgaard, Jakob

    In this paper we present a preliminary Braitenberg vehicle–like approach to combine bio-inspired audition with bio-inspired quadruped locomotion in simulation. Locomotion gaits of the salamander–like robot Salamandra robotica are modified by a lizard’s peripheral auditory system model that modula......In this paper we present a preliminary Braitenberg vehicle–like approach to combine bio-inspired audition with bio-inspired quadruped locomotion in simulation. Locomotion gaits of the salamander–like robot Salamandra robotica are modified by a lizard’s peripheral auditory system model...

  12. BIOS Security Analysis and a Kind of Trusted BIOS

    Science.gov (United States)

    Zhou, Zhenliu; Xu, Rongsheng

    The BIOS's security threats to computer system are analyzed and security requirements for firmware BIOS are summarized in this paper. Through discussion about TCG's trust transitivity, a new approach about CRTM implementation based on BIOS is developed. In this paper, we also put forward a new trusted BIOS architecture-UTBIOS which is built on Intel Framework for EFI/UEFI. The trustworthiness of UTBIOS is based on trusted hardware TPM. In UTBIOS, trust encapsulation and trust measurement are used to construct pre-OS trust chain. Performance of trust measurement is also analyzed in the end.

  13. Indirect Medical Education and Disproportionate Share Adj...

    Data.gov (United States)

    U.S. Department of Health & Human Services — Indirect Medical Education and Disproportionate Share Adjustments to Medicare Inpatient Payment Rates The indirect medical education (IME) and disproportionate share...

  14. Evaluation of the Compressive Strength of Cement-Spent Resins Matrix Mixed with Bio char

    International Nuclear Information System (INIS)

    Zalina Laili; Muhamad Samudi Yasir; Zalina Laili; Mohd Abdul Wahab; Nur Azna Mahmud; Nurfazlina Zainal Abidin

    2015-01-01

    The evaluation of compressive strength of cement-spent resins matrix mixed with bio char was investigated. In this study, bio char with different percentage (5 %, 8 %, 11 % 14 % and 18 %) was used as alternative admixture material for cement solidification of spent resins. Some properties of the physical and chemical of spent resins and bio char were also investigated. The performance of cemented spent resins with the addition of bio char was evaluated based on their compressive strength and the water resistance test. The compressive strength was evaluated at three different curing periods of 7, 14 and 28 days, while 4 weeks of immersion in distilled water was chosen for water resistance test. The result indicated that the compressive strength at 7, 14 and 28 days of curing periods were above the minimum criterion for example > 3.45 MPa of acceptable level for cemented waste form. Statistical analysis showed that there was no significant relationship between the compressive strength of the specimen and the percentage of bio char content. Result from the water resistance test showed that only one specimen that contained of 5 % of bio char failed the water resistance test due to the high of spent resins/ bio char ratio. The compressive strength of cement solidified spent resins was found increased after the water resistance test indicating further hydration occurred after immersed in water. The results of this study also suggest that the specimen with 8 %, 11 %, 14 % and 18 % of bio char content were resistance in water and suitable for the leaching study of radionuclides from cement-bio char-spent resins matrix. (author)

  15. Bacterial leaching as a pretreatment of refractory gold ores in sulphide matrix; La biolixiviacion como pretratamiento de menas auriferas refractarias en matriz de sulfuros

    Energy Technology Data Exchange (ETDEWEB)

    Iglesias, N.; Carranza, F.; Plaencia, I. [Universidad de Sevilla (Spain)

    1998-06-01

    In this paper the effectiveness of bacterial leaching as a pretreatment of gold ores bearing sulphide minerals is analysed. Three kinds of matrices are studied: pyrite, arsenopyrite and copper sulphides. It is concluded that bacterial leaching is an effective pretreatment for these refractory gold-bearing ores. In the case of a pyrite matrix a direct contact between the mineral and the microorganisms is necessary. In the case of copper or/and arsenic sulphide matrix, bacterial leaching may be carried out by indirect contact mechanism with effects separation, thus allowing faster kinetics than conventional bioleaching processes. This kinetics improvement reduces operation times and so the capital and operating costs. In a future, this fact may result in the enlargement of the profitable gold ore reserves, incorporating minerals that, at present, are not considered gold ores since there is not a technology, feasible from an economic point of view, for their treatment. (Author)

  16. In Situ Generated Colloid Transport of Cu and Zn in Reclaimed Mine Soil Profiles Associated with Bio solids Application

    International Nuclear Information System (INIS)

    Miller, J.O.; Karathanasis, A.D.; Matocha, C.J.

    2011-01-01

    Areas reclaimed for agricultural uses following coal mining often receive bio solids applications to increase organic matter and fertility. Transport of heavy metals within these soils may be enhanced by the additional presence of bio solids colloids. Intact monoliths from reclaimed and undisturbed soils in Virginia and Kentucky were leached to observe Cu and Zn mobility with and without bio solids application. Transport of Cu and Zn was observed in both solution and colloid associated phases in reclaimed and undisturbed forest soils, where the presence of unweathered spoil material and bio solids amendments contributed to higher metal release in solution fractions. Up to 81% of mobile Cu was associated with the colloid fraction, particularly when gabbiest was present, while only up to 18% of mobile Zn was associated with the colloid fraction. The colloid bound Cu was exchangeable by ammonium acetate, suggesting that it will release into groundwater resources.

  17. In Situ Generated Colloid Transport of Cu and Zn in Reclaimed Mine Soil Profiles Associated with Bio solids Application

    International Nuclear Information System (INIS)

    Miller, J.O.; Karathanasis, A.D.; Matocha, C.J.

    2011-01-01

    Areas reclaimed for agricultural uses following coal mining often receive bio solids applications to increase organic matter and fertility. Transport of heavy metals within these soils may be enhanced by the additional presence of bio solids colloids. Intact monoliths from reclaimed and undisturbed soils in Virginia and Kentucky were leached to observe Cu and Zn mobility with and without bio solids application. Transport of Cu and Zn was observed in both solution and colloid associated phases in reclaimed and undisturbed forest soils, where the presence of unweathered spoil material and bio solids amendments contributed to higher metal release in solution fractions. Up to 81% of mobile Cu was associated with the colloid fraction, particularly when gibbsite was present, while only up to 18% of mobile Zn was associated with the colloid fraction. The colloid bound Cu was exchangeable by ammonium acetate, suggesting that it will release into groundwater resources.

  18. Catalytic applications of bio-inspired nanomaterials

    Science.gov (United States)

    Pacardo, Dennis Kien Balaong

    The biomimetic synthesis of Pd nanoparticles was presented using the Pd4 peptide, TSNAVHPTLRHL, isolated from combinatorial phage display library. Using this approach, nearly monodisperse and spherical Pd nanoparticles were generated with an average diameter of 1.9 +/- 0.4 nm. The peptide-based nanocatalyst were employed in the Stille coupling reaction under energy-efficient and environmentally friendly reaction conditions of aqueous solvent, room temperature and very low catalyst loading. To this end, the Pd nanocatalyst generated high turnover frequency (TOF) value and quantitative yields using ≥ 0.005 mol% Pd as well as catalytic activities with different aryl halides containing electron-withdrawing and electron-donating groups. The Pd4-capped Pd nanoparticles followed the atom-leaching mechanism and were found to be selective with respect to substrate identity. On the other hand, the naturally-occurring R5 peptide (SSKKSGSYSGSKGSKRRIL) was employed in the synthesis of biotemplated Pd nanomaterials which showed morphological changes as a function of Pd:peptide ratio. TOF analysis for hydrogenation of olefinic alcohols showed similar catalytic activity regardless of nanomorphology. Determination of catalytic properties of these bio-inspired nanomaterials are important as they serve as model system for alternative green catalyst with applications in industrially important transformations.

  19. Leaching of plastic additives to marine organisms

    International Nuclear Information System (INIS)

    Koelmans, Albert A.; Besseling, Ellen; Foekema, Edwin M.

    2014-01-01

    It is often assumed that ingestion of microplastics by aquatic species leads to increased exposure to plastic additives. However, experimental data or model based evidence is lacking. Here we assess the potential of leaching of nonylphenol (NP) and bisphenol A (BPA) in the intestinal tracts of Arenicola marina (lugworm) and Gadus morhua (North Sea cod). We use a biodynamic model that allows calculations of the relative contribution of plastic ingestion to total exposure of aquatic species to chemicals residing in the ingested plastic. Uncertainty in the most crucial parameters is accounted for by probabilistic modeling. Our conservative analysis shows that plastic ingestion by the lugworm yields NP and BPA concentrations that stay below the lower ends of global NP and BPA concentration ranges, and therefore are not likely to constitute a relevant exposure pathway. For cod, plastic ingestion appears to be a negligible pathway for exposure to NP and BPA. - Highlights: • Uptake of plastic additives after plastic ingestion was modeled for worms and fish. • This was done for bisphenol A and nonylphenol. • Uncertainty was accounted for by Monte Carlo simulations. • It appeared that exposure by plastic ingestion was negligible for fish. • Plastic ingestion may occasionally be relevant for marine worms. - Leaching of nonylphenol and bisphenol A from ingested microplastic may be relevant for the lugworm, but is irrelevant for fish like cod

  20. YACON INULIN LEACHING DURING HOT WATER BLANCHING

    Directory of Open Access Journals (Sweden)

    Caroline Fenner Scher

    2015-10-01

    Full Text Available ABSTRACTYacon roots contain inulin, which has prebiotic properties and it may be used as sucrose or fat substitutes. However, inulin is very soluble in water. The loss of this important nutrient during blanching is caused mainly by diffusion or leaching, which might be diminished if blanching temperature - time conditions are correctly employed. The aim of this study was to determine the leaching of the sugars inulin, glucose and fructose, present in yacon roots, during hot water blanching under different time/temperature conditions. The samples were cleaned and peeled and cut into geometric forms of 1.75 ± 0.35 mm thick disks. A complete factorial experimental design was used, and the treatments of the samples were compared using the Tukey test. The results indicated that the time and temperature were significant in the dissolution of the sugars. The lowest inulin losses occurred at temperatures and times lower than 60 ºC and 3 minutes. For all temperatures, the lowest glucose and fructose losses were obtained at time lower than 3 and 5 minutes, respectively.

  1. Combinatorial Nano-Bio Interfaces.

    Science.gov (United States)

    Cai, Pingqiang; Zhang, Xiaoqian; Wang, Ming; Wu, Yun-Long; Chen, Xiaodong

    2018-06-08

    Nano-bio interfaces are emerging from the convergence of engineered nanomaterials and biological entities. Despite rapid growth, clinical translation of biomedical nanomaterials is heavily compromised by the lack of comprehensive understanding of biophysicochemical interactions at nano-bio interfaces. In the past decade, a few investigations have adopted a combinatorial approach toward decoding nano-bio interfaces. Combinatorial nano-bio interfaces comprise the design of nanocombinatorial libraries and high-throughput bioevaluation. In this Perspective, we address challenges in combinatorial nano-bio interfaces and call for multiparametric nanocombinatorics (composition, morphology, mechanics, surface chemistry), multiscale bioevaluation (biomolecules, organelles, cells, tissues/organs), and the recruitment of computational modeling and artificial intelligence. Leveraging combinatorial nano-bio interfaces will shed light on precision nanomedicine and its potential applications.

  2. Indirect costs of rheumatoid arthritis

    Directory of Open Access Journals (Sweden)

    Filip Raciborski

    2015-12-01

    Full Text Available It is estimated that in Poland about 400,000 persons in general suffer from inflammatory joint diseases, including rheumatoid arthritis (RA. Epidemiological surveys documenting the frequency and disturbance of musculoskeletal disorders in the Polish population are few in number. Most of the estimations are based on epidemiological data from other countries (prevalence of 0.5–1%. According to the data of the National Health Fund in Poland 135,000–157,000 persons in total are treated because of rheumatoid arthritis per year [ICD10 (International Statistical Classification of Diseases and Related Health Problems: M05, M06]. In the case of this group of diseases indirect costs significantly outweigh the direct costs. Indirect costs increase together with activity level of the disease. The cost analysis of productivity loss of RA patients indicates that sickness absenteeism and informal care are the most burdensome. At the national level it amounts in total from 1.2 billion to 2.8 billion PLN per year, depending on the method of analysis. These costs could be significantly reduced through early diagnosis and introduction of effective treatment.

  3. Do infants detect indirect reciprocity?

    Science.gov (United States)

    Meristo, Marek; Surian, Luca

    2013-10-01

    In social interactions involving indirect reciprocity, agent A acts prosocially towards B and this prompts C to act prosocially towards A. This happens because A's actions enhanced its reputation in the eyes of third parties. Indirect reciprocity may have been of central importance in the evolution of morality as one of the major mechanisms leading to the selection of helping and fair attitudes. Here we show that 10-month-old infants expect third parties to act positively towards fair donors who have distributed attractive resources equally between two recipients, rather than toward unfair donors who made unequal distributions. Infants' responses were dependent on the reciprocator's perceptual exposure to previous relevant events: they expected the reciprocator to reward the fair donor only when it had seen the distributive actions performed by the donors. We propose that infants were able to generate evaluations of agents that were based on the fairness of their distributive actions and to generate expectations about the social preferences of informed third parties. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Indirect reciprocity with trinary reputations.

    Science.gov (United States)

    Tanabe, Shoma; Suzuki, Hideyuki; Masuda, Naoki

    2013-01-21

    Indirect reciprocity is a reputation-based mechanism for cooperation in social dilemma situations when individuals do not repeatedly meet. The conditions under which cooperation based on indirect reciprocity occurs have been examined in great details. Most previous theoretical analysis assumed for mathematical tractability that an individual possesses a binary reputation value, i.e., good or bad, which depends on their past actions and other factors. However, in real situations, reputations of individuals may be multiple valued. Another puzzling discrepancy between the theory and experiments is the status of the so-called image scoring, in which cooperation and defection are judged to be good and bad, respectively, independent of other factors. Such an assessment rule is found in behavioral experiments, whereas it is known to be unstable in theory. In the present study, we fill both gaps by analyzing a trinary reputation model. By an exhaustive search, we identify all the cooperative and stable equilibria composed of a homogeneous population or a heterogeneous population containing two types of players. Some results derived for the trinary reputation model are direct extensions of those for the binary model. However, we find that the trinary model allows cooperation under image scoring under some mild conditions. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. Indirect Cost Reimbursement: An Industrial View.

    Science.gov (United States)

    Bolton, Robert

    1987-01-01

    The meaning of indirect costs in an industrial environment is discussed. Other factors considered are corporate policies; nature of work being supported; the uniqueness of the work; who is doing the negotiating for industry; and indirect rates. Suggestions are offered for approaches to indirect cost reimbursement. (Author/MLW)

  6. Language shifts in free indirect discourse

    NARCIS (Netherlands)

    Maier, Emar

    Free indirect discourse is a way of reporting what a protagonist thinks or says that is distinct from both direct and indirect discourse. In particular, while pronouns and tenses are presented from the narrator's perspective, as in indirect discourse, other indexical and expressive elements reflect

  7. Directe en indirecte werknemersparticipatie in Europa

    NARCIS (Netherlands)

    van Houten, Gijs; Akkerman, Agnes; Sluiter, Roderick; Jansen, Giedo; Vermeylen, Greet

    2016-01-01

    This study looks at different forms of direct and indirect employee participation in the EU. The research questions are: (1) which forms of direct and indirect employee participation can we distinguish?; (2) to what extent do forms of direct and indirect employee participation coincide within

  8. Comparison of leach results from field and laboratory prepared samples

    International Nuclear Information System (INIS)

    Oblath, S.B.; Langton, C.A.

    1985-01-01

    The leach behavior of saltstone prepared in the laboratory agrees well with that from samples mixed in the field using the Littleford mixer. Leach rates of nitrates and cesium from the current reference formulation saltstone were compared. The laboratory samples were prepared using simulated salt solution; those in the field used Tank 50 decontaminated supernate. For both nitrate and cesium, the field and laboratory samples showed nearly identical leach rates for the first 30 to 50 days. For the remaining period of the test, the field samples showed higher leach rates with the maximum difference being less than a factor of three. Ruthenium and antimony were present in the Tank 50 supernate in known amounts. Antimony-125 was observed in the leachate and a fractional leach rate was calculated to be at least a factor of ten less than that of 137 Cs. No 106 Ru was observed in the leachate, and the release rate was not calculated. However, based on the detection limits for the analysis, the ruthenium leach rate must also be at least a factor of ten less than cesium. These data are the first measurements of the leach rates of Ru and Sb from saltstone. The nitrate leach rates for these samples were 5 x 10 -5 grams of nitrate per square cm per day after 100 days for the laboratory samples and after 200 days for the field samples. These values are consistent with the previously measured leach rates for reference formulation saltstone. The relative standard deviation in the leach rate is about 15% for the field samples, which all were produced from one batch of saltstone, and about 35% for the laboratory samples, which came from different batches. These are the first recorded estimates of the error in leach rates for saltstone

  9. Clinical application of bio ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Anu, Sharma, E-mail: issaranu@gmail.com; Gayatri, Sharma, E-mail: sharmagayatri@gmail.com [Department of Chemistry, Govt. College of Engineering & Technology, Bikaner, Rajasthan (India)

    2016-05-06

    Ceramics are the inorganic crystalline material. These are used in various field such as biomedical, electrical, electronics, aerospace, automotive and optical etc. Bio ceramics are the one of the most active areas of research. Bio ceramics are the ceramics which are biocompatible. The unique properties of bio ceramics make them an attractive option for medical applications and offer some potential advantages over other materials. During the past three decades, a number of major advances have been made in the field of bio ceramics. This review focuses on the use of these materials in variety of clinical scenarios.

  10. Clinical application of bio ceramics

    International Nuclear Information System (INIS)

    Anu, Sharma; Gayatri, Sharma

    2016-01-01

    Ceramics are the inorganic crystalline material. These are used in various field such as biomedical, electrical, electronics, aerospace, automotive and optical etc. Bio ceramics are the one of the most active areas of research. Bio ceramics are the ceramics which are biocompatible. The unique properties of bio ceramics make them an attractive option for medical applications and offer some potential advantages over other materials. During the past three decades, a number of major advances have been made in the field of bio ceramics. This review focuses on the use of these materials in variety of clinical scenarios.

  11. Accelerated Leach Test(s) Program: Annual report

    International Nuclear Information System (INIS)

    Dougherty, D.R.; Pietrzak, R.F.; Fuhrmann, M.; Colombo, P.

    1986-09-01

    A computerized data base of LLW leaching data has been developed. Long-term tests on portland cement, bitumen and vinyl ester-styrene (VES) polymer waste forms containing simulated wastes are underway which are designed to identify and evaluate factors that accelerate leaching without changing the mechanisms

  12. Nitrate leaching and pesticide use in energy crops

    DEFF Research Database (Denmark)

    Jørgensen, Uffe

    2006-01-01

    Nitrate leaching measured below willow and miscanthus is very low from the established crops. Pesticide use in energy crops is low as well.......Nitrate leaching measured below willow and miscanthus is very low from the established crops. Pesticide use in energy crops is low as well....

  13. LEACHING BOUNDARY IN CEMENT-BASED WASTE FORMS

    Science.gov (United States)

    Cement-based fixation systems are among the most commonly employed stabilization/solidification techniques. These cement haste mixtures, however, are vulnerable to ardic leaching solutions. Leaching of cement-based waste forms in acetic acid solutions with different acidic streng...

  14. Package characterization by laboratory leaching and diffusion experiments using radionuclides

    International Nuclear Information System (INIS)

    Das, H.A.

    1989-01-01

    The leaching of solid inorganic waste from loaded concrete or cement by incoming water can be described in terms of a steady-state outward diffusion of the saturated solution, formed inside the pores. In this paper, the derived equations permit the prediction of long-term leaching behavior. Radiotracer experiments enable the determination of the parameters involved

  15. Developments of uranium and gold ores heap leaching technologies

    International Nuclear Information System (INIS)

    Tian Yuan; Guan Zibin; Gao Renxi

    1998-01-01

    The author reviews developments in heap leaching of uranium and gold ores at home and abroad, summarises condition of application. The author also presents problems having to be studied and settled urgently in heap leaching of uranium and gold ores in China

  16. Leaching of RA-226 contaminated gravel using different aqueous treatments

    Energy Technology Data Exchange (ETDEWEB)

    Mamoon, A; Abulfaraj, W H; Sohsah, M A [King Abdulaziz University, Jeddah, Saudi Arbabia (Saudi Arabia)

    1997-12-31

    Investigation of the efficiencies of different aqueous leaching treatments was carried out on gravel artificially contaminated with Ra-226. The extent of leaching efficiency was determined in terms of Ra-226 and its daughter Rn-222. Liquid scintillation counting using high efficiency mineral oil based liquid scintillator was the technique adopted for measuring Ra-226 and Rn-222 leached off the contaminated gravel. Water, dilute solutions of barium chloride and HCl were used as leachants. Different masses of gravel were leached with 200 mL of leachant for various contact time periods. The leached Rn-222 activity measured was plotted vs the decay factor e; from which Rn-222 and Ra-226 originally present in the sample were determined. Several leaching parameters were tested; namely type of leachant, leachant volume/gravel mass ratio, leachant contact time, effect of varying Ba Cl{sub 2} concentration, and successive leaching. Optimization of the leaching parameters for desorption of Ra-226 off the contaminated gravel under laboratory conditions may help determine the ideal conditions for remediating soil contaminated with radium or chemically similar radionuclides. 7 figs.

  17. An experimental study on gold precipitation from leach solutions of ...

    African Journals Online (AJOL)

    This paper presents the results of the study dedicated to the determination of the optimum parameters for the electrolytic gold precipitation from thiourea leach solutions. The leaching was carried out using technogenic gold-bearing raw materials (gold-bearing sands) of the Far East of the Russian Federation. The study ...

  18. Static leaching of uraniferous shales on open areas

    International Nuclear Information System (INIS)

    Hernandez Nieto, J.; Cordero, G.; Villarrubia, M.

    1973-01-01

    This report describes the tests on acid heap leaching with conventional (1.400 ppm U 3 O 8 ) crushed uranium ores. We use open circuits with low internal recycled. Using starving acidity in the leaching solutions we obtain a smooth solubilization of uranium and, at the same time, the pregnant liquors are good for the solvent extraction recovery. (Author)

  19. Aqueous-chlorine leaching of typical Canadian uranium ores

    International Nuclear Information System (INIS)

    Haque, K.E.

    1982-01-01

    Laboratory-scale aqueous-chlorine leaches were conducted on quartz-pebble conglomerates, pegmatite and vein-type ores. Optimum leach temperatures, pulp density and retention times were determined. Uranium extraction of 98 per cent was obtained from the Elliot Lake, Madawaska Mines of Bancroft and Rabbit Lake ores, 96 per cent from the Key Lake ore and 86 per cent from the Agnew Lake ore. However, tailings containing 15-20 pCi g -1 of radium-226 were obtained only from the Elliot Lake and Agnew lake quartz-pebble conglomerates and Bancroft pegmatite-type ores by second-stage leaches with HCl. The second-stage leach results indicate that multistage (3 or 4) acid-chloride or salt-chloride leaches might be effective to obtain tailings containing 15-20 pCi 226 Ra g -1 from the high-grade vein-type ores. Comparative reagent-cost estimates show that the sulphuric-acid leach process is far less expensive than aqueous chlorine leaching. Nevertheless, only the aqueous chlorine and acid-chloride leaches in stages are effective in producing tailings containing 15-20 pCi 226 Ra g -1 from the typical Canadian uranium ores. (Auth.)

  20. Manual of acid in situ leach uranium mining technology

    International Nuclear Information System (INIS)

    2001-08-01

    In situ leaching (ISL) technology recovers uranium using two alternative chemical leaching systems - acid and alkaline. This report brings together information from several technical disciplines that are an essential part of ISL technology. They include uranium geology, geohydrology, chemistry as well as reservoir engineering and process engineering. This report provides an extensive description of acid ISL uranium mining technology

  1. Manual of acid in situ leach uranium mining technology

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-08-01

    In situ leaching (ISL) technology recovers uranium using two alternative chemical leaching systems - acid and alkaline. This report brings together information from several technical disciplines that are an essential part of ISL technology. They include uranium geology, geohydrology, chemistry as well as reservoir engineering and process engineering. This report provides an extensive description of acid ISL uranium mining technology.

  2. Scheduling of Irrigation and Leaching Requirements

    Directory of Open Access Journals (Sweden)

    Amer Hassan Al-haddad

    2015-03-01

    Full Text Available Iraq depends mainly on Tigris and Euphrates Rivers to provide high percentage of agricultural water use for thousands years. At last years, Iraq is suffering from shortage in water resources due to global climate changes and unfair water politics of the neighboring countries, which affected the future of agriculture plans for irrigation, added to that the lack of developed systems of water management in the irrigation projects and improper allocation of irrigation water, which reduces water use efficiency and lead to losing irrigation water and decreasing in agricultural yield. This study aims at studying the usability of irrigation and leaching scheduling within the irrigating projects and putting a complete annual or seasonal irrigation program as a solution for the scarcity of irrigation water, the increase of irrigation efficiency, lessening the salinity in the projects and preparing an integral irrigation calendar through field measurements of soil physical properties and chemical for project selected and compared to the results of the irrigation scheduling and leaching with what is proposed by the designers. The process is accomplished by using a computer program which was designed by Water Resources Department at the University of Baghdad, with some modification to generalize it and made it applicable to various climatic zone and different soil types. Study area represented by large project located at the Tigris River, and this project was (Al-Amara irrigation project. Sufficient samples of project's soil were collected so as to identify soil physical and chemical properties and the salinity of soil and water as well as identifying the agrarian cycles virtually applied to this project. Finally, a comparison was conducted between the calculated water quantities and the suggested ones by the designers. The research results showed that using this kind of scheduling (previously prepared irrigation and leaching scheduling with its properties

  3. A probabilistic assessment of climate change impacts on yield and nitrogen leaching from winter wheat in Denmark

    Directory of Open Access Journals (Sweden)

    C. D. Børgesen

    2011-09-01

    Full Text Available Climate change will impact agricultural production both directly and indirectly, but uncertainties related to likely impacts constrain current political decision making on adaptation. This analysis focuses on a methodology for applying probabilistic climate change projections to assess modelled wheat yields and nitrate leaching from arable land in Denmark. The probabilistic projections describe a range of possible changes in temperature and precipitation. Two methodologies to apply climate projections in impact models were tested. Method A was a straightforward correction of temperature and precipitation, where the same correction was applied to the baseline weather data for all days in the year, and method B used seasonal changes in precipitation and temperature to correct the baseline weather data. Based on climate change projections for the time span 2000 to 2100 and two soil types, the mean impact and the uncertainty of the climate change projections were analysed. Combining probability density functions of climate change projections with crop model simulations, the uncertainty and trends in nitrogen (N leaching and grain yields with climate change were quantified. The uncertainty of climate change projections was the dominating source of uncertainty in the projections of yield and N leaching, whereas the methodology to seasonally apply climate change projections had a minor effect. For most conditions, the probability of large yield reductions and large N leaching losses tracked trends in mean yields and mean N leaching. The impacts of the uncertainty in climate change were higher for loamy sandy soil than for sandy soils due to generally higher yield levels for loamy sandy soils. There were large differences between soil types in response to climate change, illustrating the importance of including soil information for regional studies of climate change impacts on cropping systems.

  4. Hydrochloric acid leach of Agnew Lake uranium concentrate

    International Nuclear Information System (INIS)

    Haque, K.E.; Ipekoglue, B.

    1981-10-01

    Hydrochloric acid leaching was conducted on the radioactive mineral concentrate separated from the Agenw Lake uranium ore. Leach tests conducted at the optimum conditions (75 0 C; 36 hours; 66.0 Kg HCl/tonne; solid:liquid -1:1) resulted in the extraction of 87% uranium and 84% radium. The radionuclide level of the residue was U-0.016%, Th-0.24% and Ra-65 pCi/g solids. However to obtain a residue almost free of radium (i.e., Ra level at the detection limit: 4-6 pCi/g solids), the first stage leach residue was further treated with hydrochloric acid. The radium level in the best second stage leach residue was also above the target level. Therefore, multistage (3 or 4) hydrochloric acid and/or neutral chloride leaching is recommended to obtain tailings almost free of radionuclide

  5. COMPILATION OF LABORATORY SCALE ALUMINUM WASH AND LEACH REPORT RESULTS

    International Nuclear Information System (INIS)

    Harrington, S.J.

    2011-01-01

    This report compiles and analyzes all known wash and caustic leach laboratory studies. As further data is produced, this report will be updated. Included are aluminum mineralogical analysis results as well as a summation of the wash and leach procedures and results. Of the 177 underground storage tanks at Hanford, information was only available for five individual double-shell tanks, forty-one individual single-shell tanks (e.g. thirty-nine 100 series and two 200 series tanks), and twelve grouped tank wastes. Seven of the individual single-shell tank studies provided data for the percent of aluminum removal as a function of time for various caustic concentrations and leaching temperatures. It was determined that in most cases increased leaching temperature, caustic concentration, and leaching time leads to increased dissolution of leachable aluminum solids.

  6. Remediation of hazardous waste sites by heap leaching

    International Nuclear Information System (INIS)

    Samani, Z.; Hanson, A.; Dwyer, B.

    1994-01-01

    Efforts are being made to devise technologies and treatment systems to remediate contaminated soil-on site without generating significant wastes for off-site disposal. Heap leaching, a technique used extensively in the mining industry, has been investigated as a method for remediation of hazardous chemical contamination of the vadose zone. In the mining industry, metal-bearing ore is excavated and mounded on a pad. The metals are removed by passing a special leaching solution through the ore. In this study, the removal of chromium(VI) from the New Mexico soils (sand, sandy loam, and clay) using heap leaching was evaluated at a column scale. The heap leaching study demonstrated greater than 99% removal of Cr(VI) from all three soils using tap water as the leaching agent. (author) 13 figs., 5 tabs., 21 refs

  7. COMPILATION OF LABORATORY SCALE ALUMINUM WASH AND LEACH REPORT RESULTS

    Energy Technology Data Exchange (ETDEWEB)

    HARRINGTON SJ

    2011-01-06

    This report compiles and analyzes all known wash and caustic leach laboratory studies. As further data is produced, this report will be updated. Included are aluminum mineralogical analysis results as well as a summation of the wash and leach procedures and results. Of the 177 underground storage tanks at Hanford, information was only available for five individual double-shell tanks, forty-one individual single-shell tanks (e.g. thirty-nine 100 series and two 200 series tanks), and twelve grouped tank wastes. Seven of the individual single-shell tank studies provided data for the percent of aluminum removal as a function of time for various caustic concentrations and leaching temperatures. It was determined that in most cases increased leaching temperature, caustic concentration, and leaching time leads to increased dissolution of leachable aluminum solids.

  8. A novel bioreactor system for simultaneous mutli-metal leaching from industrial pyrite ash: Effect of agitation and sulphur dosage.

    Science.gov (United States)

    Panda, Sandeep; Akcil, Ata; Mishra, Srabani; Erust, Ceren

    2018-01-15

    Simultaneous multi-metal leaching from industrial pyrite ash is reported for the first time using a novel bioreactor system that allows natural diffusion of atmospheric O 2 and CO 2 along with the required temperature maintenance. The waste containing economically important metals (Cu, Co, Zn & As) was leached using an adapted consortium of meso-acidophilic Fe 2+ and S oxidising bacteria. The unique property of the sample supported adequate growth and activity of the acidophiles, thereby, driving the (bio) chemical reactions. Oxido-reductive potentials were seen to improve with time and the system's pH lowered as a result of active S oxidation. Increase in sulphur dosage (>1g/L) and agitation speed (>150rpm) did not bear any significant effect on metal dissolution. The consortium was able to leach 94.01% Cu (11.75% dissolution/d), 98.54% Co (12.3% dissolution/d), 75.95% Zn (9.49% dissolution/d) and 60.80% As (7.6% dissolution/d) at 150rpm, 1g/L sulphur, 30°C in 8days. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Bio-tribology.

    Science.gov (United States)

    Dowson, Duncan

    2012-01-01

    It is now forty six years since the separate topics of friction, lubrication, wear and bearing design were integrated under the title 'Tribology' [Department of Education and Science, Lubrication (Tribology) Education and Research. A Report on the Present Position and Industry's Needs, HMSO, London, 1966]. Significant developments have been reported in many established and new aspects of tribology during this period. The subject has contributed to improved performance of much familiar equipment, such as reciprocating engines, where there have been vast improvements in engine reliability and efficiency. Nano-tribology has been central to remarkable advances in information processing and digital equipment. Shortly after widespread introduction of the term tribology, integration with biology and medicine prompted rapid and extensive interest in the fascinating sub-field now known as Bio-tribology [D. Dowson and V. Wright, Bio-tribology, in The Rheology of Lubricants, ed. T. C. Davenport, Applied Science Publishers, Barking, 1973, pp. 81-88]. An outline will be given of some of the developments in the latter field.

  10. Radiocesium leaching from contaminated litter in forest streams

    International Nuclear Information System (INIS)

    Sakai, Masaru; Gomi, Takashi; Naito, Risa S.; Negishi, Junjiro N.; Sasaki, Michiko; Toda, Hiroto; Nunokawa, Masanori; Murase, Kaori

    2015-01-01

    In Japanese forests suffering from the Fukushima Daiichi Nuclear Power Plant accident, litter fall provides a large amount of radiocesium from forests to streams. Submerged litter is processed to become a vital food resource for various stream organisms through initial leaching and subsequent decomposition. Although leaching from litter can detach radiocesium similarly to potassium, radiocesium leaching and its migration are poorly understood. We examined both radiocesium and potassium leaching to the water column and radiocesium allocation to minerals (glass beads, silica sand, and vermiculite) in the laboratory using soaked litter with and without minerals on a water column. The mineral types did not affect radiocesium leaching from litter, but soaking in water for 1, 7, and 30 days decreased the radiocesium concentration in litter by ×0.71, ×0.66, and ×0.56, respectively. Meanwhile, the 1-, 7-, and 30-day experiments decreased potassium concentration in litter by ×0.17, ×0.11, and ×0.09, respectively. Leached radiocesium remained in a dissolved form when there was no mineral phases present in the water, whereas there was sorption onto the minerals when they were present. In particular, vermiculite adsorbed radiocesium by two to three orders of magnitude more effectively than the other minerals. Because radiocesium forms (such as that dissolved or adsorbed to organic matter or minerals) can further mobilize to ecosystems, our findings will increase our understanding regarding the dynamics of radiocesium in stream ecosystems. - Highlights: • Radiocesium in contaminated litter was leached when soaked in water. • Radiocesium in litter leached slowly compared to potassium. • Minerals adsorbed dissolved radiocesium that was leached from litter. • Vermiculite effectively adsorbed radiocesium leached from litter

  11. SULPHUR DIOXIDE LEACHING OF URANIUM CONTAINING MATERIAL

    Science.gov (United States)

    Thunaes, A.; Rabbits, F.T.; Hester, K.D.; Smith, H.W.

    1958-12-01

    A process is described for extracting uranlum from uranium containing material, such as a low grade pitchblende ore, or mill taillngs, where at least part of the uraniunn is in the +4 oxidation state. After comminuting and magnetically removing any entrained lron particles the general material is made up as an aqueous slurry containing added ferric and manganese salts and treated with sulfur dioxide and aeration to an extent sufficient to form a proportion of oxysulfur acids to give a pH of about 1 to 2 but insufficient to cause excessive removal of the sulfur dioxide gas. After separating from the solids, the leach solution is adjusted to a pH of about 1.25, then treated with metallic iron in the presence of a precipitant such as a soluble phosphate, arsonate, or fluoride.

  12. Leach characterization of cement encapsulated wastes

    International Nuclear Information System (INIS)

    Roy, D.M.; Scheetz, B.E.; Wakeley, L.D.; Barnes, M.W.

    1982-01-01

    Matrix encapsulation of defense nuclear waste as well as intermediate-level commercial wastes within a low-temperature cementitious composite were investigated. The cements for this study included both as-received and modified calcium silicate and calcium aluminate cements. Specimens were prepared following conventional formulation techniques designed to produce dense monoliths, followed by curing at 60 0 C. An alternative preparation procedure is contrasted in which the specimens were ''warm'' pressed in a uniaxial press at 150 0 C at 50,000 psi for 0.5 h. Specimens of the waste/cement composites were leached in deionized water following three different procedures which span a wide range of temperatures and solution saturation conditions. Aluminate and compositionally adjusted silicate cements exhibited a better retentivity for Cs and Sr than did the as-received silicate cement. 15 refs

  13. Building a Uranium Heap Leach Project

    International Nuclear Information System (INIS)

    Schnell, Henry

    2014-01-01

    Despite all these we have seen many HL successes and many interesting projects coming down the pipe. • Previous experience in Uranium with previous ROM projects in France (Bessines, Langone), Niger (Somair), Canada (Agnew Lake) and other locations had provided some basic background. • Heap leach based on copper experience with crushed ore has operated for many years in Brazil (Caetite). • Many gold operations for many decades in all climates and continents. • Copper at +20% of production, many in Chile, but also now in many other countries. • Uranium with agglomerated crushed ores is now becoming more prominent – Somair, Imouraren, Trekkopje. • Work also ongoing for Ranger, Rossing, and in consideration for other projects. • Other notable work in Nickel, and multi-metal such as Talvivaara

  14. Groundwater remediation in the Straz leaching operation

    International Nuclear Information System (INIS)

    Novak, J.

    2001-01-01

    The locality affected by consequences of the chemical mining of the uranium during underground leaching 'in situ' is found in the area of the Czech Republic in the northeastern part of the Ceska Lipa district. In the contribution the complex groundwater remediation project is discussed. First, the risks of the current state are expressed. Then the alternatives of remediation of the both Cenomanian and Turonian aquifers are presented. Evaluation of the remediation alternatives with the view to the time-consumption, economy, ecology and the elimination of unacceptable risks for the population and environment is done. Finally, the present progress of remediation and the conception of remediation of chemical mining on deposit of Straz pod Ralskem are presented. (orig.)

  15. Pesticide leaching in a changing climate

    DEFF Research Database (Denmark)

    Rasmussen, Signe Bonde

    There is a widespread consensus among scientists that the climate will change in the future, and that this change has already begun. These climatic changes will undoubtedly challenge the use of pesticides, which has been proposed to increase in the future. Accordingly, the primary aim of this Ph......D-project was to contribute to the knowledge of how climate change will effect pesticide leaching in the future, which was done by use of mathematical modelling. The agro-ecological model Daisy, was used in all simulations, as well as the 2 model soils: a coarse sand and a subsurface drained sandy loam containing......, resulting in 3000-year long weather series of statistically stationary climate. Effects of pesticide properties (sorption and degradation), pesticide application dates, and soil properties were included. The synthetic weather series produced in relation to objective (II) were used to simulate future changes...

  16. Life cycle assessment and residue leaching: The importance of parameter, scenario and leaching data selection

    DEFF Research Database (Denmark)

    Allegrini, Elisa; Butera, Stefania; Kosson, D.S.

    2015-01-01

    of systems and products and can be applied to waste management systems to identify environmental benefits and critical aspects thereof. From an LCA perspective, residue utilisation provides benefits such as avoiding the production and depletion of primary materials, but it can lead to environmental burdens......Residues from industrial processes and waste management systems (WMSs) have been increasingly reutilised, leading to landfilling rate reductions and the optimisation of mineral resource utilisation in society. Life cycle assessment (LCA) is a holistic methodology allowing for the analysis......, due to the potential leaching of toxic substances. In waste LCA studies where residue utilisation is included, leaching has generally been neglected. In this study, municipal solid waste incineration bottom ash (MSWI BA) was used as a case study into three LCA scenarios having different system...

  17. Experimental leaching of uranium from tuffaceous rocks

    International Nuclear Information System (INIS)

    Goodell, P.C.; Trentham, R.C.

    1980-07-01

    The premise to be tested in this work is that felsic volcanic rocks particularly ash-flow tuffs, can serve as source rocks for certain uranium deposits. The applicability of this idea to several geologic environments is investigated. A genetic model is developed dealing with the behavior of uranium during and subsequent to ash-flow tuff deposition. It is based upon previously described investigations, geologic logic, data presented here, and speculation. Ash-flow tuff sequences described in the literature show significant alkali element variation, particularly in thick tuff units. Some variation is attributed to initial magma variations, whereas additional change may be produced during cooling and degassing of the tuff. Uranium variations have been documented in tuff sequences which are assumed to represent magmatic compositions. Uranium may be released during the initial degassing, during hydrothermal alteration, and/or during later diagenesis. Experimental studies have been designed and carried out to simulate natural leaching conditions such as might occur during diagenesis. Synthetic ground waters have been pumped through pulverized uraniferous vitrophyres. Major and minor element contents have been determined. The most significant chemical changes take place quickly, within a matter of days. Several starting and product leachant solutions were analyzed fluorimetrically for uranium. They show significant increases in uranium contents, from less than 1 ppB at the start to greater than 10 ppB maximu. Such leachant solutions might be significant transport agents of uranium given geologic time. Leaching at low temperatures appears to involve a thin surface reaction and diffusion layer. Both dissolution and ion exchange influence the leachant composition. It is also concluded that glassy ash-flow tuffs may serve as uranium source rocks during low temperature diagenetic changes

  18. Bio-threat microparticle simulants

    Science.gov (United States)

    Farquar, George Roy; Leif, Roald N

    2012-10-23

    A bio-threat simulant that includes a carrier and DNA encapsulated in the carrier. Also a method of making a simulant including the steps of providing a carrier and encapsulating DNA in the carrier to produce the bio-threat simulant.

  19. Bio-threat microparticle simulants

    Energy Technology Data Exchange (ETDEWEB)

    Farquar, George Roy; Leif, Roald

    2014-09-16

    A bio-threat simulant that includes a carrier and DNA encapsulated in the carrier. Also a method of making a simulant including the steps of providing a carrier and encapsulating DNA in the carrier to produce the bio-threat simulant.

  20. Laboratory studies on leaching of low grade uranium ores and treatment of low level liquid waste generated by leaching experiments

    International Nuclear Information System (INIS)

    Palabrica, O.T.; Antonino, E.J.; Caluag, L.A.; Villamater, D.

    1980-07-01

    Acid leaching experiments of preconcentrated uranium ore were carried out at a pulp density of 50% solids, using sulfuric acid with sodium chlorate as oxidant. The different leaching parameters considered in this work were temperature, oxidant level and leaching time. In the experimental procedure, the concentration of oxidant and the temperature were varied to determine how they affect the leaching process. Experimental results are illustrated in tabulated form for better interpretation. Uranium analyses were done by fluorimetric and delayed-neutron activation analysis. An anion exchange method using Dowex 1 x 8, 200-400 mesh (Cl - ) was used in treating the low-level liquid waste generated by leaching experiments. The purpose of this treatment was to minimize radioactive contamination in the waste materials and also to recover some of the uranium left in the liquid waste. (author)

  1. Speciation and environmental risk assessment of heavy metal in bio-oil from liquefaction/pyrolysis of sewage sludge.

    Science.gov (United States)

    Yuan, Xingzhong; Leng, Lijian; Huang, Huajun; Chen, Xiaohong; Wang, Hou; Xiao, Zhihua; Zhai, Yunbo; Chen, Hongmei; Zeng, Guangming

    2015-02-01

    Liquefaction bio-oil (LBO) produced with ethanol (or acetone) as the solvent and pyrolysis bio-oil (PBO) produced at 550°C (or 850°C) from sewage sludge (SS) were produced, and were characterized and evaluated in terms of their heavy metal (HM) composition. The total concentration, speciation and leaching characteristic of HMs (Cu, Cr, Pb, Zn, Cd, and Ni) in both LBO and PBO were investigated. The total concentration and exchangeable fraction of Zn and Ni in bio-oils were at surprisingly high levels. Quantitative risk assessment of HM in bio-oils was performed by the method of risk assessment code (RAC), potential ecological risk index (PERI) and geo-accumulation index (GAI). Ni in bio-oil produced by pyrolysis at 850°C (PBO850) and Zn in bio-oil by liquefaction at 360°C with ethanol as solvent (LBO-360E) were evaluated to possess very high risk to the environment according to RAC. Additionally, Cd in PBO850 and LBO-360E were evaluated by PERI to have very high risk and high risk, respectively, while Cd in all bio-oils was assessed moderately contaminated according to GAI. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Leach testing of waste glasses under near-saturation conditions

    International Nuclear Information System (INIS)

    Strachan, D.M.; Grambow, B.

    1983-11-01

    Two waste glasses, MCC 76 to 68 and C31 to 3, were leached in deionized water and 0.001 M MgCl 2 for periods up to 158 days. At 57 days the gel layer was removed from some of the specimens and leaching continued for up to 100 days. Results from leaching in deionized water showed that the gel layer was not protective. Results from leaching in 0.001 M MgCl 2 are in good agreement with the predicted results obtained from the use of the PHREEQE geochemical code and with sepiolite [Mg 2 Si 3 O 6 (OH) 4 ] as the Mg-bearing precipitate. Both B and Si were predicted and observed to increase with increasing glass dissolution while maintaining sepiolite solubility. Both MCC 76 to 68 and C31 to 3 glasses showed increased leaching in 0.001 M MgCl 2 upon removal of the layer. This suggests a leaching mechanism whereby leaching is driven by the formation of an alteration product

  3. Defense High-Level Waste Leaching Mechanisms Program. Final report

    International Nuclear Information System (INIS)

    Mendel, J.E.

    1984-08-01

    The Defense High-Level Waste Leaching Mechanisms Program brought six major US laboratories together for three years of cooperative research. The participants reached a consensus that solubility of the leached glass species, particularly solubility in the altered surface layer, is the dominant factor controlling the leaching behavior of defense waste glass in a system in which the flow of leachant is constrained, as it will be in a deep geologic repository. Also, once the surface of waste glass is contacted by ground water, the kinetics of establishing solubility control are relatively rapid. The concentrations of leached species reach saturation, or steady-state concentrations, within a few months to a year at 70 to 90 0 C. Thus, reaction kinetics, which were the main subject of earlier leaching mechanisms studies, are now shown to assume much less importance. The dominance of solubility means that the leach rate is, in fact, directly proportional to ground water flow rate. Doubling the flow rate doubles the effective leach rate. This relationship is expected to obtain in most, if not all, repository situations

  4. Technique for in situ leach simulation of uranium ores

    International Nuclear Information System (INIS)

    Grant, D.C.; Seidel, D.C.; Nichols, I.L.

    1985-01-01

    In situ uranium mining offers the advantages of minimal environmental disturbance, low capital and operating costs, and reduced mining development time. It is becoming an increasingly attractive mining method for the recovery of uranium from secondary ore deposits. In order to better understand the process, a laboratory technique was developed and used to study and simulate both the chemical and physical phenomena occurring in ore bodies during in situ leaching. The laboratory simulation technique has been used to determine effects of leaching variables on permeability, uranium recovery, and post-leach aquifer restoration. This report describes the simulation system and testing procedure in sufficient detail to allow the construction of the system, and to perform the desired leaching tests. With construction of such a system, in situ leaching of a given ore using various leach conditions can be evaluated relatively rapidly in the laboratory. Not only could optimum leach conditions be selected for existing ore bodies, but also exploitation of new ore bodies could be accelerated. 8 references, 8 figures, 2 tables

  5. Leach rate studies on glass containing actual radioactive waste

    International Nuclear Information System (INIS)

    Walker, D.D.; Wiley, J.R.; Dukes, M.D.; LeRoy, J.H.

    1980-01-01

    Borosilicate glass containing radioactive wastes from the Savannah River Plant have been leached for 900 days. The International Standards Organization's (ISO) static leach test procedure was used on glass buttons in various leachants. Leach rates based on 90 Sr and 137 Cs analyses were similar: 2 x 10 -8 to 3 x 10 -8 g/(cm 2 )(d) in distilled water, 1 x 10 -8 to 3 x 10 -7 g/(cm 2 )(d) in pH 7 buffer, 3 x 10 -7 to 7 x 10 -7 g/(cm 2 )(d) in pH 9 buffer, and 7 x 10 -6 to 8 x 10 -5 g/(cm 2 )(d) in pH 4 buffer. Rates based on Pu analyses were the same as above in distilled water and pH 9 buffer, but were lower by an order of magnitude in pH 4 and pH 7 buffers. Almost all leach rates remained constant between 200 and 900 days of leaching. Increasing the concentration of the buffering agents had no effect on the leach rates at pH 7 (phosphate) and pH 9 (carbonate), but dramatically increased the rates at pH 4 (acetate). Leach rates did not differ significantly between high aluminum and high iron waste glasses

  6. Thiosulfate leaching of gold from waste mobile phones.

    Science.gov (United States)

    Ha, Vinh Hung; Lee, Jae-chun; Jeong, Jinki; Hai, Huynh Trung; Jha, Manis K

    2010-06-15

    The present communication deals with the leaching of gold from the printed circuit boards (PCBs) of waste mobile phones using an effective and less hazardous system, i.e., a copper-ammonia-thiosulfate solution, as an alternative to the conventional and toxic cyanide leaching of gold. The influence of thiosulfate, ammonia and copper sulfate concentrations on the leaching of gold from PCBs of waste mobile phones was investigated. Gold extraction was found to be enhanced with solutions containing 15-20 mM cupric, 0.1-0.14 M thiosulfate, and 0.2-0.3 M ammonia. Similar trends were obtained for the leaching of gold from two different types of scraps and PCBs of waste mobile phones. From the scrap samples, 98% of the gold was leached out using a solution containing 20 mM copper, 0.12 M thiosulfate and 0.2 M ammonia. Similarly, the leaching of gold from the PCBs samples was also found to be good, but it was lower than that of scrap samples in similar experimental conditions. In this case, only 90% of the gold was leached, even with a contact time of 10h. The obtained data will be useful for the development of processes for the recycling of gold from waste mobile phones. Copyright 2010 Elsevier B.V. All rights reserved.

  7. Leaching experiment of cement solidified waste form under unsaturated condition

    International Nuclear Information System (INIS)

    Wang Zhiming; Yao Laigen; Li Shushen; Zhao Yingjie; Cai Yun; Li Dan; Han Xinsheng; An Yongfeng

    2003-01-01

    A device for unsaturated leaching experiments was designed and built up. 8 different sizes, ranging from 40.2 cm 3 to 16945.5 cm 3 , of solidified waste form were tested in the experiment. 5 different water contents, from 0.15 to 0.40, were used for the experiment. The results show that the cumulative leaching fraction increases with water content when the sizes of the forms are equal to and less than 4586.7 cm 3 , for example, the ratios of the cumulative leaching fractions are between 1.24-1.41 under water content of 0.35 and 0.15 on 360 day of Teaching. It can also be seen that the cumulative leaching fraction under higher water content is close to that under saturated condition. The cumulative leaching fraction decreases with size of the form. Maximum leached depth of the solidified waste forms is about 2.25 cm after one year Teaching. Moreover, it has no clear effect on cumulative leaching fraction that sampling or non-sampling during the experiment

  8. Defense High-Level Waste Leaching Mechanisms Program. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Mendel, J.E. (compiler)

    1984-08-01

    The Defense High-Level Waste Leaching Mechanisms Program brought six major US laboratories together for three years of cooperative research. The participants reached a consensus that solubility of the leached glass species, particularly solubility in the altered surface layer, is the dominant factor controlling the leaching behavior of defense waste glass in a system in which the flow of leachant is constrained, as it will be in a deep geologic repository. Also, once the surface of waste glass is contacted by ground water, the kinetics of establishing solubility control are relatively rapid. The concentrations of leached species reach saturation, or steady-state concentrations, within a few months to a year at 70 to 90/sup 0/C. Thus, reaction kinetics, which were the main subject of earlier leaching mechanisms studies, are now shown to assume much less importance. The dominance of solubility means that the leach rate is, in fact, directly proportional to ground water flow rate. Doubling the flow rate doubles the effective leach rate. This relationship is expected to obtain in most, if not all, repository situations.

  9. Analysis of SPR salt cavern remedial leach program 2013.

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Paula D.; Gutierrez, Karen A.; Lord, David L.; Rudeen, David Keith

    2013-09-01

    The storage caverns of the US Strategic Petroleum Reserve (SPR) exhibit creep behavior resulting in reduction of storage capacity over time. Maintenance of oil storage capacity requires periodic controlled leaching named remedial leach. The 30 MMB sale in summer 2011 provided space available to facilitate leaching operations. The objective of this report is to present the results and analyses of remedial leach activity at the SPR following the 2011 sale until mid-January 2013. This report focuses on caverns BH101, BH104, WH105 and WH106. Three of the four hanging strings were damaged resulting in deviations from normal leach patterns; however, the deviations did not affect the immediate geomechanical stability of the caverns. Significant leaching occurred in the toes of the caverns likely decreasing the number of available drawdowns until P/D ratio criteria are met. SANSMIC shows good agreement with sonar data and reasonably predicted the location and size of the enhanced leaching region resulting from string breakage.

  10. HSP as bio dosemeters

    International Nuclear Information System (INIS)

    Manzanares A, E.; Vega C, H.R.

    2005-01-01

    A review of the more important passages for the field of the radiological protection, from the discovery, beginnings of the utilization of the radiations emitting, passing to the legislation proposals and the transformations that had been suffer to establish the international standards of radiological protection. The paradigms on the effects and chronologically the emanated discoveries of the cellular research and the measurement of cellular products in the species and the diverse alive beings making emphasis in evaluating the expression of the heat-shock proteins caused by low doses of gamma radiation, these are used as radiation bio monitors and of other agents that cause cellular stress and lastly a prospective of the future of the radiobiology. (Author)

  11. Bio-prospecting of distillery yeasts as bio-control and bio-remediation agents.

    Science.gov (United States)

    Ubeda, Juan F; Maldonado, María; Briones, Ana I; Francisco, J Fernández; González, Francisco J

    2014-05-01

    This work constitutes a preliminary study in which the capacity of non-Saccharomyces yeasts isolated from ancient distilleries as bio-control agents against moulds and in the treatment of waste waters contaminated by heavy metals-i.e. bio-remediation-is shown. In the first control assays, antagonist effect between non-Saccharomyces yeasts, their extracts and supernatants against some moulds, analysing the plausible (not exhaustive) involved factors were qualitatively verified. In addition, two enzymatic degrading properties of cell wall plant polymers, quitinolitic and pectinolitic, were screened. Finally, their use as agents of bio-remediation of three heavy metals (cadmium, chromium and lead) was analysed semi-quantitatively. The results showed that all isolates belonging to Pichia species effectively inhibited all moulds assayed. Moreover, P. kudriavzevii is a good candidate for both bio-control and bio-remediation because it inhibited moulds and accumulated the major proportion of the three tested metals.

  12. Leaching of CCA-treated wood: implications for waste disposal

    International Nuclear Information System (INIS)

    Townsend, Timothy; Tolaymat, Thabet; Solo-Gabriele, Helena; Dubey, Brajesh; Stook, Kristin; Wadanambi, Lakmini

    2004-01-01

    Leaching of arsenic, chromium, and copper from chromated copper arsenate (CCA)-treated wood poses possible environmental risk when disposed. Samples of un-weathered CCA-treated wood were tested using a variety of the US regulatory leaching procedures, including the toxicity characteristic leaching procedure (TCLP), synthetic precipitation leaching procedure (SPLP), extraction procedure toxicity method (EPTOX), waste extraction test (WET), multiple extraction procedure (MEP), and modifications of these procedures which utilized actual MSW landfill leachates, a construction and demolition (C and D) debris leachate, and a concrete enhanced leachate. Additional experiments were conducted to assess factors affecting leaching, such as particle size, pH, and leaching contact time. Results from the regulatory leaching tests provided similar results with the exception of the WET, which extracted greater quantities of metals. Experiments conducted using actual MSW leachate, C and D debris leachate, and concrete enhanced leachate provided results that were within the same order of magnitude as results obtained from TCLP, SPLP, and EPTOX. Eleven of 13 samples of CCA-treated dimensional lumber exceeded the US EPA's toxicity characteristic (TC) threshold for arsenic (5 mg/L). If un-weathered arsenic-treated wood were not otherwise excluded from the definition of hazardous waste, it frequently would require management as such. When extracted with simulated rainwater (SPLP), 9 of the 13 samples leached arsenic at concentrations above 5 mg/L. Metal leachability tended to increase with decreasing particle size and at pH extremes. All three metals leached above the drinking water standards thus possibly posing a potential risk to groundwater. Arsenic is a major concern from a disposal point of view with respect to ground water quality

  13. Leach behavior of hydrofracture grout incorporating radioactive wastes

    International Nuclear Information System (INIS)

    Moore, J.G.; Godbee, H.W.; Kibbey, A.H.

    1976-01-01

    Rates at which Sr, Cs, Pu, and Cm are leached from hydrofracture grout were measured. The fraction of an isotope leached varied with the square root of time if the leachant was replaced more frequently than once per day, but was inhibited or depressed if replacement was made less often. The amount of Sr or Cs leached from the grout varied directly with the degree of drying during curing and inversely with the time of curing. Of the clay additives studied for enhancing cesium retention, Grundite, while satisfactory, was the least effective. In general, the isotope leach rate followed the order: Cs greater than Sr greater than Cm greater than Pu. The amount leached as a function of the leachant varied in the order: distilled water greater than tap water greater than grout water. Concentrating the waste by a factor of up to 4 before grouting had little effect on the leach rate. Comparison with results for other products indicates that the grout can provide leach rates comparable to those for wastes incorporated into borosilicate glass. Theoretical relationships that consider diffusion and instantaneous reaction (an equilibrium or time-dependent relationship between mobile and immobile forms of a species) were in good agreement with the data for the 28-day-cured grout when the leachant was initially replaced twice per day. The credibility of laboratory results with simulated waste was substantiated by a short-term continuous leach test made on a fragment of a core sample of actual hydrofracture grout. The modified effective diffusivities (10 -11 to 10 -10 cm 2 /s, equivalent to a leach rate of the order of 10 -7 g cm -2 day -1 ) for Sr and Cs calculated from these data are comparable to laboratory values. 17 figures, 5 tables

  14. Extended Leach Testing of Simulated LAW Cast Stone Monoliths

    Energy Technology Data Exchange (ETDEWEB)

    Serne, R. Jeffrey [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Westsik, Joseph H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Williams, Benjamin D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jung, H. B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wang, Guohui [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-07-09

    This report describes the results from long-term laboratory leach tests performed at Pacific Northwest National Laboratory (PNNL) for Washington River Protection Solutions (WRPS) to evaluate the release of key constituents from monoliths of Cast Stone prepared with four simulated low-activity waste (LAW) liquid waste streams. Specific objectives of the Cast Stone long-term leach tests described in this report focused on four activities: 1. Extending the leaching times for selected ongoing EPA-1315 tests on monoliths made with LAW simulants beyond the conventional 63-day time period up to 609 days reported herein (with some tests continuing that will be documented later) in an effort to evaluate long-term leaching properties of Cast Stone to support future performance assessment activities. 2. Starting new EPA-1315 leach tests on archived Cast Stone monoliths made with four LAW simulants using two leachants (deionized water [DIW] and simulated Hanford Integrated Disposal Facility (IDF) Site vadose zone pore water [VZP]). 3. Evaluating the impacts of varying the iodide loading (starting iodide concentrations) in one LAW simulant (7.8 M Na Hanford Tank Waste Operations Simulator (HTWOS) Average) by manufacturing new Cast Stone monoliths and repeating the EPA-1315 leach tests using DIW and the VZP leachants. 4. Evaluating the impacts of using a non-pertechnetate form of Tc that is present in some Hanford tanks. In this activity one LAW simulant (7.8 M Na HTWOS Average) was spiked with a Tc(I)-tricarbonyl gluconate species and then solidified into Cast Stone monoliths. Cured monoliths were leached using the EPA-1315 leach protocol with DIW and VZP. The leach results for the Tc-Gluconate Cast Stone monoliths were compared to Cast Stone monoliths pertechnetate.

  15. Indirect Self-Destructiveness and Emotional Intelligence.

    Science.gov (United States)

    Tsirigotis, Konstantinos

    2016-06-01

    While emotional intelligence may have a favourable influence on the life and psychological and social functioning of the individual, indirect self-destructiveness exerts a rather negative influence. The aim of this study has been to explore possible relations between indirect self-destructiveness and emotional intelligence. A population of 260 individuals (130 females and 130 males) aged 20-30 (mean age of 24.5) was studied by using the Polish version of the chronic self-destructiveness scale and INTE, i.e., the Polish version of the assessing emotions scale. Indirect self-destructiveness has significant correlations with all variables of INTE (overall score, factor I, factor II), and these correlations are negative. The intensity of indirect self-destructiveness differentiates significantly the height of the emotional intelligence and vice versa: the height of the emotional intelligence differentiates significantly the intensity of indirect self-destructiveness. Indirect self-destructiveness has negative correlations with emotional intelligence as well as its components: the ability to recognize emotions and the ability to utilize emotions. The height of emotional intelligence differentiates the intensity of indirect self-destructiveness, and vice versa: the intensity of indirect self-destructiveness differentiates the height of emotional intelligence. It seems advisable to use emotional intelligence in the prophylactic and therapeutic work with persons with various types of disorders, especially with the syndrome of indirect self-destructiveness.

  16. Novel precipitation technique for uranium recovery from carbonate leach solutions

    International Nuclear Information System (INIS)

    Sujoy Biswas; Rupawate, V.H.; Hareendran, K.N.; Roy, S.B.; Chakravartty, J.K.

    2015-01-01

    The recovery of uranium from carbonate ore leach solution was studied using novel precipitation method. The uranium from leach liquor was recovered as magnesium diuranate with NaOH in presence of trace amount of Mg 2+ . Effects of various parameters such as addition of H 2 SO 4 , MgO, MgSO 4 as well as NaOH were investigated for maximum uranium recovery. Overall uranium recovery of the process was 97 % with improved particle size (∼57 µm). Based on the experimental findings, a process flow-sheet was developed for uranium recovery from carbonate ore leach solution with a uranium concentration of <1 g/L. (author)

  17. The Iron Removal in Marmatite Concentrate Pressure Leaching Process

    Science.gov (United States)

    Wen-bo, LUO; Ji-kun, WANG; Yin, GAN

    2018-01-01

    To modify the pressure leaching technology of horizontal autoclave using marmatite concentrate, an appropriate increase in the pulp’s residence time in the horizontal autoclave is required. This increase will provide sufficient time for leaching to be completed in the first three chambers of the horizontal autoclave. Adding zinc oxide ore and potassium sulfate in the fourth chamber of the horizontal autoclave is needed to complete preliminary neutralization and iron precipitation in the horizontal autoclave. The pilot plant experimental results of the proposed technology are satisfactory, further shortening the process of pressure leaching and improving its economic efficiency.

  18. Present and future: heap leaching of uranium ore in China

    International Nuclear Information System (INIS)

    Li Jianhua

    2010-01-01

    Based on small and disperse uranium deposits, and low grade ores, heap leaching has been developed as the dominating technique in the uranium production of China. It is indicated that heap leaching technique has such advantages as less capital, low cost, low power consumption and water consumption. At the meanwhile, heap leaching technique presents shortcomings of poor adaptability and low recovery rate. In order to meet the oncoming enormous demand of nuclear power, great effort shall be put on research of new technology, new equipment, new material. (authors)

  19. Hydrodynamics and mass transfer in trickle leaching process

    International Nuclear Information System (INIS)

    Jin Suoqing; Xiang Qinfang; Guo Jianzheng

    1995-01-01

    The initial research results of the hydrodynamic behavior and mass transfer of the trickle leaching process are summarized. It was shown that the dropping mode, the height of uranium ore heap and the flow rate of the dropping fluid affect the mass transfer of the trickle leaching process. Based on the concept of the keeping form of liquid in ore particle bed and the diffusion in porous medium, a mass transfer pattern, i.e. 'double-membrane transfer process' controlled by porous diffusion, was presented and proved for trickle leaching process

  20. Leaching of heavy metals from timah langat amang

    International Nuclear Information System (INIS)

    Shukri bin Othman

    1990-01-01

    Accelerated leaching studies of amang from Timah Langat for heavy metals showed that the material was rather stable. From almost 24 types of heavy metals contained in the material, the metal that leached out most was Al, followed by Pb, U, Cu, Mn, Fe, Mg, Y and La but at smaller quantities. The studies also showed that amang was very porous. The high seepage rate resulted in the solubilities of the metals not reaching equilibrium. In that situation, the leaching of heavy metals from amang was dependent on the seepage rate of water, the height of the material, the volume of water that seeped through and the solubility of the metals

  1. Production of bio-energies

    International Nuclear Information System (INIS)

    Gurtler, J.L.; Femenias, A.; Blondy, J.

    2009-01-01

    After having indicated the various possible origins of biomass, this paper considers the issue of bio-energies, i.e., energies produced with biomass related to forest or agriculture production. Some indicators are defined (share of renewable energies, share of biomass in the energy production and consumption, number of production units). Stake holders are identified. Then, major and emerging trends are identified and discussed. The major trends are: development and diversification of renewable energies, development of bio-fuels with the support of incentive policies, prevalence of the wood-energy sector on the whole renewable energies, increase of surfaces dedicated to bio-fuels since the end of the 1990's, a French biogas sector which is late with respect to other countries. The emerging trends are: the important role of oil price in the development of bio-fuels, a necessary public support for the development of biogas, mobilization of research and development of competitiveness poles for bio-industries. Some prospective issues are also discussed in terms of uncertainties (soil availabilities, environmental performance of bio-fuels, available biomass resource, need of a technological advance, and evolution of energy needs on a medium term, tax and public policy). Three hypotheses of bio-energy evolutions are discussed

  2. Bio diesel production from algae

    International Nuclear Information System (INIS)

    Khola, G.; Ghazala, B.

    2011-01-01

    Algae appear to be an emerging source of biomass for bio diesel that has the potential to completely displace fossil fuel. Two thirds of earth's surface is covered with water, thus alga e would truly be renewable option of great potential for global energy needs. This study discusses specific and comparative bio diesel quantitative potential of Cladophora sp., also highlighting its biomass (after oil extraction), pH and sediments (glycerine, water and pigments) quantitative properties. Comparison of Cladophora sp., with Oedogonium sp., and Spirogyra sp., (Hossain et al., 2008) shows that Cladophora sp., produce higher quantity of bio diesel than Spirogyra sp., whereas biomass and sediments were higher than the both algal specimens in comparison to the results obtained by earlier workers. No prominent difference in pH of bio diesel was found. In Pakistan this is a first step towards bio diesel production from algae. Results indicate that Cladophora sp., provide a reasonable quantity of bio diesel, its greater biomass after oil extraction and sediments make it a better option for bio diesel production than the comparing species. (author)

  3. Uranium nanoparticle synthesis from leaching solution

    International Nuclear Information System (INIS)

    Sadowski, Z.; Sklodowska, A.

    2014-01-01

    The removal of uranium from leaching and bioleaching solutions is of great significance for an environment protection. In comparison with conventional separation techniques, synthesis of uranium nanoparticles has a number of benefits. It has been demonstrated that the uranium nanoparticles show high catalytic activity. In the present studies a variety of synthesis systems have been used for reduction of uranium from bioleaching solution. Among various catalytical templates the hematite Fe_2O_3 nanoparticles are most interest It was presented the report on development of synthesis method to produce nano structured Fe_2O_3 particles. The efficiency of hematite nanoparticles for adsorption of uranium ions from bioleaching solutions was investigated. Bacterial leaching is alternate technique used to extract uranium from mining wastes. The bioleaching process is environment friendly and gives the extraction yield of over 90%. The bioleaching solutions were obtained from bioleaching experiments using waste materials from different places at Lower Silesia (Kowary, Grzmiaca, Kopaniec, Radoniow). Chemoautotrophic bacteria were used for bioleaching tests. The significant adsorption capacity of U(VI) onto iron oxide and hydroxides (goethite, hematite, and magnetite) was observed. The sorption of U(VI) onto the hematite surface was connected with the chemical reduction of U(VI) to U(IV) by Fe"2"+ ions. The initial reaction system contained excess of Fe"2"+ ions which were used to reduce of U(VI). The reduction of U(VI) occurred at pH at the vicinity of pH=2.4. The colloid particles of hematite with UO_2 nanoparticles were obtained. The results of zeta potential measurements of hematite nanoparticles showed that at the ionic strength equals 10"-"3M NaCl, the average zeta potential was +32.4±3.5 mV at pH = 2.6. The interaction of hematite nanoparticles with the bioleaching solutions led to decrease of positive zeta potential to the value of 6.4± 2.7 mV. (author)

  4. Leaching of transuranics observed in lysimeter experiments

    International Nuclear Information System (INIS)

    Eriksson, A.; Fredriksson, L.

    1994-01-01

    Transuranic elements in fallout are generally bound in oxide particles, size from submicron to several microns. During the fallout they can be intercepted on plant covers or reach the soil surface. The particles can be re-suspended to the air and reach other residence sites, be linked into the food chain or be redistributed in other ways (Cf Essington et al. 1976) before eventually being incorporated into the soil. The fate of such particles in the soil depends on the size and on the nature of the particulate matter and on environmental factors, the climate and the properties of the soil. In a dry climate the particles tend to be kept intact long time, (Schulz et al. 1976) and they are more easily redistributed than in a humid climate with plant covered moist and living soils. In the former the particles move more easily in the soil profile than in the latter, the particle matter is very slowly dissolved and the average availability of the deposited nuclides for plant uptake can be assumed to be comparatively low. The downward movements of the particles or nuclide compounds bound to small soil particles are enhanced by the swelling and shrinking of soil caused by absorption and depletion of water during the season. Cracks and fissures are created and closed several times a year in soils rich in colloidal material. Sandy soils with coarse material have less cracks, but in dry conditions the empty pore space may allow transport of fine particles. The coarser material also has less specific area and sorption capacity. The nuclide compounds leached with the drainage water in coarse soils should be less retarded than in clays (Cf. Rai and Serne, 1977; Nishita and Haug, 1979 and Rai et al., 1980). The lysimeter installation used for the study reported below was primarily designed to study the plant uptake of transuranics from a number of Swedish soils. However, as such an installation in many ways well simulate field conditions and at the same time is a closed system

  5. Evaluation of the leaching behavior of incineration bottom ash using seawater: A comparison with standard leaching tests.

    Science.gov (United States)

    Lin, Wenlin Yvonne; Heng, Kim Soon; Nguyen, Minh Quan; Ho, Jin Rui Ivan; Mohamed Noh, Omar Ahmad Bin; Zhou, Xue Dong; Liu, Alec; Ren, Fei; Wang, Jing-Yuan

    2017-04-01

    Batch and column tests were conducted on untreated incineration bottom ash (IBA) samples from two incineration plants in Singapore, using seawater as the leachant. The main objective of this study was to investigate the change in the leaching behavior of certain elements (i.e. As, Cd, Cr, Cu, Ni, Pb, Sb, Se and Zn) when IBA comes into contact with seawater. Such an investigation using seawater as leachant was not commonly carried out when investigating leaching behavior in IBA. The leaching tests were then carried out on the same IBA samples using DI water, as a comparison. Lower level of leaching was observed for Pb and Zn when seawater was used as the leachant. Cr and Sb showed significant cumulative release at Liquid-to-Solids (L/S) ratio 5 in the seawater column leaching. The influence of Dissolved Organic Carbon (DOC) on Cu leaching seems to decrease after L/S 2 when using seawater in the column test. Although the leaching behavior of IBA was affected when seawater was used, for the column test, there was no significant difference during the initial release when compared to DI water. The initial L/S fractions collected were important as the low L/S ratios represent the pore water concentration and the maximum output in an actual application. The results from this study would be useful for the future study on using IBA in marine applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Effects of Pregnant Leach Solution Temperature on the Permeability of Gravelly Drainage Layer of Heap Leaching Structures

    Directory of Open Access Journals (Sweden)

    mehdi amini

    2013-12-01

    Full Text Available In copper heap leaching structures, the ore is leached by an acidic solution. After dissolving the ore mineral, the heap is drained off in the acidic solution using a drainage system (consisting of a network of perforated polyethylene pipes and gravelly drainage layers and is, then, transferred to the leaching plant for copper extraction where the copper is extracted and the remaining solution is dripped over the ore heap for re-leaching. In this process, the reaction between the acidic solution and copper oxide ore is exothermal and the pregnant leach solution (PLS, which is drained off the leaching heap, has a higher temperature than the dripped acidic solution. The PLS temperature variations cause some changes in the viscosity and density which affect the gravelly drainage layer's permeability. In this research, a special permeability measuring system was devised for determining the effects of the PLS temperature variations on the permeability coefficient of the gravelly drainage layer of heap leaching structures. The system, consisting of a thermal acid resistant element and a thermocouple, controls the PLS temperature, which helps measure the permeability coefficient of the gravelly drainage layer. The PLS and gravelly drainage layer of Sarcheshmeh copper mine heap leaching structure No. 1 were used in this study. The permeability coefficient of the gravelly soil was measured against the PLS and pure water at temperatures varying between 3°C to 60°C. Also, the viscosity and density of the PLS and pure water were measured at these temperatures and, using existing theoretical relations, the permeability coefficient of the gravel was computed. A comparison between the experimental and theoretical results revealed a good conformity between the two sets of results. Finally, a case (Taft heap leaching structure, Yazd, Iran was studied and its gravelly drainage layer was designed based on the results of the present research.

  7. Kinetics of acid leaching of ilmenite decomposed by KOH part 1: decomposition by KOH and leaching by HCl

    International Nuclear Information System (INIS)

    Nayl, A.A; Aly, H.F.

    2010-01-01

    Decomposition of ilmenite by KOH solutions, to convert titanium to potassium titanate, was first studied . This was followed by leaching titanium from the ilmenite paste using HCl solutions in the temperature range 50-150 degree C for different periods up to 3 hr. The significant factors affecting the leaching process were studied. The experimental data of the decomposition rate of ilmenite by KOH and of the formed KOH paste by HCl under the relevant operating variables were interpreted with the shrinking core model under chemically controlled process. The apparent activation energy for leaching of titanium in both cases bas been evaluated and discussed.

  8. Navigating the Bio-Politics of Childhood

    Science.gov (United States)

    Lee, Nick; Motzkau, Johanna

    2011-01-01

    Childhood research has long shared a bio-political terrain with state agencies in which children figure primarily as "human futures". In the 20th century bio-social dualism helped to make that terrain navigable by researchers, but, as life processes increasingly become key sites of bio-political action, bio-social dualism is becoming…

  9. Bacterial leaching of pyritic gold ores

    International Nuclear Information System (INIS)

    Gagliardi, F.M.; Cashion, J.D.; Brown, J.; Jay, W.H.

    1998-01-01

    Full text: Pyritic ores (pyrite and arsenopyrite) containing gold concentrations in excess of 50g Au/t can be processed to recover the gold by the removal of the sulphur from the ore. This may be achieved by roasting (producing sulphur dioxide emissions), pressure oxidation (expensive and suitable for large high grade deposits), pressure leaching (still currently being developed) or bacterial oxidation. The bacterial oxidation process is a well known process in nature but has only recently come under investigation as a economically viable and relatively clean method of gold recovery from deep low grade sulphidic ores. Samples were obtained from the Wiluna Gold Mine in Western Australia consisting of the original ore, six successive bacterial reactors and the final products. Moessbauer experiments have been performed at room temperature, liquid nitrogen and liquid helium temperatures, and in applied magnetic fields. The main components of the iron phases which were present during the bacterial treatment were pyrite and arsenopyrite which were readily oxidised by the bacteria. Ferric sulfates and ferric arsenates were identified as by-products of the process with a small amount of the oxyhydroxide goethite. These results are in contrast to the similar study of the Fairview Mine in South Africa where principally Fe(II) species were observed

  10. Bacterial leaching of pyritic gold ores

    Energy Technology Data Exchange (ETDEWEB)

    Gagliardi, F.M.; Cashion, J.D.; Brown, L.J. [Monash Univ., Clayton, VIC (Australia). Dept. of Physics; Jay, W.H. [Monash Univ., Clayton, VIC (Australia). Chemical Engineering Department

    1996-12-31

    The bacterial oxidation process is well known in nature but has only recently come under investigation as a viable and relatively clean method of gold recovery from ores. However there is currently little information about the process at an atomic scale. It is known that the bacterial attack progresses preferentially along grain boundaries which is precisely where the gold has been deposited from aqueous infiltration. Samples have been obtained from the Wiluna mine in Western Australia consisting of the original ore, 2 pre-treatments, and from six successive bacterial reactors. {sup 57}Fe Moessbauer spectra taken at room temperature show only two quadrupole split doublets which can be ascribed to pyrite, FeS{sub 2}, and arsenopyrite, FeAsS. However, the presence of any superparamagnetic oxide or oxyhydroxide species would be expected to give a spectrum very similar to that of pyrite and would be undetectable in small quantities. At a temperature of 5K, a broad magnetically split sextet is observable with a mean hyperfine field of approximately 50T. This field is characteristic of magnetically ordered ferric iron surrounded by an octahedron of oxygens. The intensity and characteristics of this subspectrum alters through the series and interpretations will be given on the oxidation products of the bacterial leaching

  11. Bacterial leaching of pyritic gold ores

    International Nuclear Information System (INIS)

    Gagliardi, F.M.; Cashion, J.D.; Brown, L.J.; Jay, W.H.

    1996-01-01

    The bacterial oxidation process is well known in nature but has only recently come under investigation as a viable and relatively clean method of gold recovery from ores. However there is currently little information about the process at an atomic scale. It is known that the bacterial attack progresses preferentially along grain boundaries which is precisely where the gold has been deposited from aqueous infiltration. Samples have been obtained from the Wiluna mine in Western Australia consisting of the original ore, 2 pre-treatments, and from six successive bacterial reactors. 57 Fe Moessbauer spectra taken at room temperature show only two quadrupole split doublets which can be ascribed to pyrite, FeS 2 , and arsenopyrite, FeAsS. However, the presence of any superparamagnetic oxide or oxyhydroxide species would be expected to give a spectrum very similar to that of pyrite and would be undetectable in small quantities. At a temperature of 5K, a broad magnetically split sextet is observable with a mean hyperfine field of approximately 50T. This field is characteristic of magnetically ordered ferric iron surrounded by an octahedron of oxygens. The intensity and characteristics of this subspectrum alters through the series and interpretations will be given on the oxidation products of the bacterial leaching

  12. Mesophilic leaching of copper sulphide sludge

    Directory of Open Access Journals (Sweden)

    VLADIMIR B. CVETKOVSKI

    2009-02-01

    Full Text Available Copper was precipitated using a sodium sulphide solution as the precipitation agent from an acid solution containing 17 g/l copper and 350 g/l sulphuric acid. The particle size of nearly 1 µm in the sulphide sludge sample was detected by optical microscopy. Based on chemical and X-ray diffraction analyses, covellite was detected as the major sulphide mineral. The batch bioleach amenability test was performed at 32 °C on the Tk31 mine mesophilic mixed culture using a residence time of 28 days. The dissolution of copper sulphide by direct catalytic leaching of the sulphides with bacteria attached to the particles was found to be worthy, although a small quantity of ferrous ions had to be added to raise the activity of the bacteria and the redox potential of the culture medium. Throughout the 22-day period of the bioleach test, copper recovery based on residue analysis indicated a copper extraction of 95 %, with copper concentration in the bioleach solution of 15 g/l. The slope of the straight line tangential to the exponential part of the extraction curve gave a copper solubilisation rate of 1.1 g/l per day. This suggests that a copper extraction of 95 % for the period of bioleach test of 13.6 days may be attained in a three-stage bioreactor system.

  13. Radionuclide Leaching from Organic Ion Exchange Resin

    International Nuclear Information System (INIS)

    Delegard, C.H.; Rinehart, D.E.

    1998-01-01

    Laboratory tests were performed to examine the efficacy of leach treatments for decontaminating organic ion exchange resins (OIER), which have been found in a number of samples retrieved from K East Basin sludge. Based on process records, the OIER found in the K Basins is a mixed-bet strong acid/strong base material marketed as Purolitetrademark NRW-037. Radionuclides sorbed or associated with the OIER can restrict its disposal to the Environmental Restoration Disposal Facility (ERDF). The need for testing to support development of a treatment process for K Basin sludge has been described in Section 4.2 of ''Testing Strategy to Support the Development of K Basins Sludge Treatment Process'' (Flament 1998). To help understand the effects of anticipated OIER elutriation and washing, tests were performed with well-rinsed OIER material from K East Basin floor sludge (sample H-08 BEAD G) and with well-rinsed OIER having approximately 5% added K East canister composite sludge (sample KECOMP). The rinsed resin-bearing material also contained the inorganic ion exchanger Zeolon-900trademark, a zeolite primarily composed of the mineral mordenite. The zeolite was estimated to comprise 27 weight percent of the dry H-08 BEAD G material

  14. Radiotracer investigation in gold leaching tanks.

    Science.gov (United States)

    Dagadu, C P K; Akaho, E H K; Danso, K A; Stegowski, Z; Furman, L

    2012-01-01

    Measurement and analysis of residence time distribution (RTD) is a classical method to investigate performance of chemical reactors. In the present investigation, the radioactive tracer technique was used to measure the RTD of aqueous phase in a series of gold leaching tanks at the Damang gold processing plant in Ghana. The objective of the investigation was to measure the effective volume of each tank and validate the design data after recent process intensification or revamping of the plant. I-131 was used as a radioactive tracer and was instantaneously injected into the feed stream of the first tank and monitored at the outlet of different tanks. Both sampling and online measurement methods were used to monitor the tracer concentration. The results of measurements indicated that both the methods provided identical RTD curves. The mean residence time (MRT) and effective volume of each tank was estimated. The tanks-in-series model with exchange between active and stagnant volume was used and found suitable to describe the flow structure of aqueous phase in the tanks. The estimated effective volume of the tanks and high degree of mixing in tanks could validate the design data and confirmed the expectation of the plant engineer after intensification of the process. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. Leaching tests of cemented organic radioactive waste

    International Nuclear Information System (INIS)

    Calabria, Jaqueline A. Almeida; Haucz, Maria Judite A.; Tello, Cledola Cassia O.

    2011-01-01

    The use of radioisotopes in research, medical and industrial activities generates organic liquid radioactive wastes. At Centro de Desenvolvimento da Tecnologia Nuclear (CDTN) are produced organic liquid wastes from different sources, one of these are the solvent extraction activities, whose the waste volume is the largest one. Therefore a research was carried out to treat them. Several techniques to treat organic liquid radioactive wastes have been evaluated, among them incineration, oxidation processes, alkaline hydrolysis, distillation, absorption and cementation. Laboratory experiments were accomplished to establish the most adequate process in order to obtain qualified products for storage and disposal. Absorption followed by cementation was the procedure used in this study, i.e. absorbent substances were added to the organic liquid wastes before mixing with the cement. Initially were defined the absorbers, and evaluated the formulation in relation to the compressive strength of its products. Bentonite from different suppliers (B and G) and vermiculite in two granulometries (M - medium and F - small) were tested. In order to assess the product quality the specimens were submitted to the leaching test according the Standard ISO 6961 and its results were evaluated. Then they were compared with the values established by Standard CNEN NN 6.09 A cceptance criteria for waste products to be disposed , to verify if they meet the requirements for safely storage and disposal. Through this study the best formulations to treat the organic wastes were established. (author)

  16. Stability of iron in clays under different leaching conditions

    Czech Academy of Sciences Publication Activity Database

    Doušová, B.; Fuitová, L.; Koloušek, D.; Lhotka, M.; Matys Grygar, Tomáš; Spurná, P.

    2014-01-01

    Roč. 62, 1-2 (2014), s. 145-152 ISSN 0009-8604 Institutional support: RVO:61388980 Keywords : Clays * Iron * Leaching Stability * Structure * Surface Properties Subject RIV: DD - Geochemistry Impact factor: 1.228, year: 2014

  17. Leaching of Nutrient Salts from Fly Ash from Biomass Combustion

    DEFF Research Database (Denmark)

    Thomsen, Kaj; Vu, Duc Thuong; Stenby, Mette

    2005-01-01

    Methods to selectively leach nutrient salts from fly ash, while leaving cadmium un-dissolved were studied. Temperature, pH, water to fly ash ratio are all expected to influence the kinetics and the equilibrium boundaries for this process. Three different leaching methods were investigated....... The first method was a counter current moving bed process in four stages. The ash was kept in filter bags and leached with water that was introduced into the bags at 40-50°C. In the second method, fly ash and water was brought into contact in a partially fluidized bed. The third method was a counter current...... moving bed process with agitation/centrifugation. It was found that a satisfactory leaching of the nutrient salts could be achieved with the third method using only two or three stages, depending on the water to fly ash ratio. It is an advantage to perform the process at temperatures above 50°C...

  18. Implementation Guidance for the Next Generation Leaching Tests

    Science.gov (United States)

    Poster provides an overview of the purpose and utility of this research, highlights of the research to support the Leaching Environmental Assessment Framework (LEAF), application and translation (including data management and analysis software), intended end users, and lessons le...

  19. Leaching behaviour of tritium from a hardened cement paste

    International Nuclear Information System (INIS)

    Matsuzuru, H.; Moriyama, N.; Ito, A.

    1979-01-01

    Leaching of tritium from a hardened cement paste into an aqueous phase has been studied to assess the safety of solidification of the tritiated liquid waste with cement. Leaching tests were carried out in accordance with the method recommended by the International Atomic Energy Agency. The leaching fraction was measured as functions of the waste-cement wt ratio (Wa/C), temperature of leachant and curing time. the tritium leachability of cements follows the order: alumina cement > Portland cement > slag cement. The fraction of tritium leached increases with increasing Wa/C and temperature and decreasing curing period. A deionized water as a leachant gives a slightly higher leachability than the synthetic sea water. The coating of the specimen surface with bitumen reduces the leachability to about 5% of its value for the specimen without coating. (author)

  20. Microwave Pretreatment for Thiourea Leaching for Gold Concentrate

    Directory of Open Access Journals (Sweden)

    Nag-Choul Choi

    2017-10-01

    Full Text Available In this research, we studied the use of microwave pretreatment to enhance the efficiency of Au leaching from gold concentrate. The gold concentrate was pretreated using microwaves with different irradiation time. The sample temperature was increased up to 950 °C by the microwave irradiation. A scanning electron microscope-energy dispersive spectrometer showed the evolution of microcracks and the reduction of sulfur on the mineral surface. X-ray diffraction data also showed the mineral phase shift from pyrite to hematite or pyrrhotite. A leaching test was conducted for the microwave-treated and untreated gold concentrates using thiourea. Although the thiourea leaching recovered 80% of Au from the untreated concentrate, from the treated concentration, the Au could be recovered completely. Au leaching efficiency increased as the microwave irradiation time increased, as well as with a higher composition of thiourea.

  1. Complex sulphide-barite ore leaching in ferric chloride solution

    Directory of Open Access Journals (Sweden)

    Miroslav Sokić

    2016-06-01

    Full Text Available The results of research on the leaching process of complex sulphide-barite ore were presented in this paper. The leaching process was carried out in a laboratory autoclave by ferric chloride solution. Considering that those minerals are represented in complex structural-textural relationships, it is not possible to extract lead, zinc and copper minerals from ore by flotation methods. The obtained results confirmed possibility of the ore processing directly, by chemical methods. The effect of temperature, time and oxygen partial pressure on the lead, zinc and copper dissolution was studied. The maximal leaching degree was achieved at 100 °C and amount of 91.5 % for Pb, 96.1 % for Zn and 60.7 % for Cu. Leaching at temperatures above 100 °C is impractical.

  2. Kinetics of molybdenite oxidizing leaching in alkali medium by ozone

    International Nuclear Information System (INIS)

    Medvedev, A.S.; Sokratova, N.B.; Litman, I.V.; Zelikman, A.N.

    1985-01-01

    On the basis of investigation of the process kinetics proposed is a model of oxidizing leaching of molybdenite in alkali medium while ozonization of the solution by ozoneair mixture. A kinetic equation is derived, that describes experimental data satisfactorily

  3. Mass Loss and Nutrient Release through Leaching in Tectona ...

    African Journals Online (AJOL)

    User

    West African Journal of Applied Ecology, vol. 24(1), 2016: 43–58. ... utilization of organic compounds in litter, and also leaching .... Department of Physics and Engineering. Physics ... The analysis was done following the method described by ...

  4. Aluminum chloride restoration of in situ leached uranium ores

    International Nuclear Information System (INIS)

    Grant, D.C.; Burgman, M.A.

    1982-01-01

    During in situ uranium mining using ammonium bicarbonate lixiviant, the ammonium exchanges with cations on the ore's clay. After mining is complete, the ammonium may desorb into post-leach ground water. For the particular ore studied, other chemicals (i.e., uranium and selenium) which are mobilized during the leach process, have also been found in the post-leach ground water. Laboratory column tests, used to simulate the leaching process, have shown that aluminum chloride can rapidly remove ammonium from the ore and thus greatly reduce the subsequent ammonium leakage level into ground water. The aluminum chloride has also been found to reduce the leakage levels of uranium and selenium. In addition, the aluminum chloride treatment produces a rapid improvement in permeability

  5. 2010 World bio-energy conference

    International Nuclear Information System (INIS)

    2010-01-01

    After having evoked the bio-energy price awarded to a Brazilian for his works on the use of eucalyptus as energy source, this report proposes a synthesis of the highlights of the conference: discussions about sustainability, bio-energies as an opportunity for developing countries, the success of bio-energies in Sweden, and more particularly some technological advances in the field of biofuels: a bio-LPG by Biofuel-solution AB, catalysis, bio-diesel from different products in a Swedish farm, a second generation ethanol by the Danish company Inbicon, a large scale methanization in Goteborg, a bio-refinery concept in Sweden, bio-gases

  6. Synchronization of indirectly coupled Lorenz oscillators

    Indian Academy of Sciences (India)

    Synchronization of indirectly coupled Lorenz oscillators: An experimental study. Amit Sharma Manish Dev Shrimali. Synchronization, Coupled Systems and Networks Volume 77 Issue 5 November 2011 pp 881-889 ... The in-phase and anti-phase synchronization of indirectly coupled chaotic oscillators reported in Phys. Rev ...

  7. Indirect search for dark matter with AMS

    International Nuclear Information System (INIS)

    Goy, Corinne

    2006-01-01

    This document summarises the potential of AMS in the indirect search for Dark Matter. Observations and cosmology indicate that the Universe may include a large amount of Dark Matter of unknown nature. A good candidate is the Ligthest Supersymmetric Particle in R-Parity conserving models. AMS offers a unique opportunity to study Dark Matter indirect signature in three spectra: gamma, antiprotons and positrons

  8. Indirectness in Discourse: Ethnicity as Conversational Style.

    Science.gov (United States)

    Tannen, Deborah

    1981-01-01

    Examines social differences in expectations of indirectness in conversations between married couples, both Greek and Greek-American. Concludes that Greeks are more likely to expect indirectness in the context presented and that Greek-Americans have retained the Greek communicative patterns. (FL)

  9. JUSTIFICATION FOR INDIRECT DISCRIMINATION IN EU

    Directory of Open Access Journals (Sweden)

    Cătălina-Adriana Ivănuş

    2014-11-01

    Full Text Available The right to non-discrimination is very important for a civilized society. EU legislation establishes direct and indirect discrimination, harassment, sexual harassment, instruction to discriminate and any less favourable treatment of a woman related to pregnancy or maternity leave as forms of discrimination. The law and the Court of Justice permit the justification of indirect discrimination.

  10. 77 FR 41899 - Indirect Food Additives: Polymers

    Science.gov (United States)

    2012-07-17

    ... DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration 21 CFR Part 177 [Docket No. FDA-2012-F-0031] Indirect Food Additives: Polymers AGENCY: Food and Drug Administration, HHS. ACTION... CFR part 177 is amended as follows: PART 177--INDIRECT FOOD ADDITIVES: POLYMERS 0 1. The authority...

  11. JUSTIFICATION FOR INDIRECT DISCRIMINATION IN EU

    OpenAIRE

    Cătălina-Adriana Ivănuş

    2014-01-01

    The right to non-discrimination is very important for a civilized society. EU legislation establishes direct and indirect discrimination, harassment, sexual harassment, instruction to discriminate and any less favourable treatment of a woman related to pregnancy or maternity leave as forms of discrimination. The law and the Court of Justice permit the justification of indirect discrimination.

  12. Indirect techniques in nuclear astrophysics: a review.

    Science.gov (United States)

    Tribble, R E; Bertulani, C A; Cognata, M La; Mukhamedzhanov, A M; Spitaleri, C

    2014-10-01

    In this review, we discuss the present status of three indirect techniques that are used to determine reaction rates for stellar burning processes, asymptotic normalization coefficients, the Trojan Horse method and Coulomb dissociation. A comprehensive review of the theory behind each of these techniques is presented. This is followed by an overview of the experiments that have been carried out using these indirect approaches.

  13. Chemical leaching of rapidly solidified Al-Si binary alloys

    International Nuclear Information System (INIS)

    Yamauchi, I.; Takahara, K.; Tanaka, T.; Matsubara, K.

    2005-01-01

    Various particulate precursors of Al 100-x Si x (x = 5-12) alloys were prepared by a rapid solidification process. The rapidly solidified structures of the precursors were examined by XRD, DSC and SEM. Most of Si atoms were dissolved into the α-Al(fcc) phase by rapid solidification though the solubility of Si in the α-Al phase is negligibly small in conventional solidification. In the case of 5 at.% Si alloy, a single α-Al phase was only formed. The amount of the primary Si phase increased with increase of Si content for the alloys beyond 8 at.% Si. Rapid solidification was effective to form super-saturated α-Al precursors. These precursors were chemically leached by using a basic solution (NaOH) or a hydrochloric acid (HCl) solution. All Al atoms were removed by a HCl solution as well as a NaOH solution. Granules of the Si phase were newly formed during leaching. The specific surface area was about 50-70 m 2 /g independent of Si content. The leaching behavior in both solutions was slightly different. In the case of a NaOH solution, the shape of the precursor often degenerated after leaching. On the other hand, it was retained after leaching by a HCl solution. Fine Si particles precipitated in the α-Al phase by annealing of as-rapidly solidified precursors at 773 K for 7.2 x 10 3 s. In this case, it was difficult to obtain any products by NaOH leaching, but a few of Si particles were obtained by HCl leaching. Precipitated Si particles were dissolved by the NaOH solution. The X-ray diffraction patterns of leached specimens showed broad lines of the Si phase and its lattice constant was slightly larger than that of the pure Si phase. The microstructures of the leached specimens were examined by transmission electron microscopy. It showed that the leached specimens had a skeletal structure composed of slightly elongated particles of the Si phase and quite fine pores. The particle size was about 30-50 nm. It was of comparable order with that evaluated by Scherer

  14. NIH NeuroBioBank

    Data.gov (United States)

    Federal Laboratory Consortium — The NIH NeuroBioBank (NBB), supported by the National Institute of Mental Health, the National Institute of Neurological Disorders and Stroke, and the Eunice Kennedy...

  15. Leaching studies of low-level radioactive waste forms

    International Nuclear Information System (INIS)

    Dayal, R.; Arora, H.; Milian, L.; Clinton, J.

    1985-01-01

    A research program has been underway at the Brookhaven National Laboratory to investigate the release of radionuclides from low-level waste forms under laboratory conditions. This paper describes the leaching behavior of Cs-137 from two major low-level waste streams, that is, ion exchange bead resin and boric acid concentrate, solidified in Portland cement. The resultant leach data are employed to evaluate and predict the release behavior of Cs-137 from low-level waste forms under field burial conditions

  16. Process for the in-situ leaching of uranium

    International Nuclear Information System (INIS)

    Habib, E.T.; Vogt, T.C.

    1982-01-01

    Process for the in-situ leaching of uranium employing an alkaline lixiviant and an alkali metal or alkaline earth metal hypochlorite as an oxidizing agent. The use of the hypochlorite oxidant results in significantly higher uranium recoveries and leaching rates than those attained by the use of conventional oxidants. The invention is particularly suitable for use in subterranean deposits in which the uranium mineral is associated with carbonaceous material which retards access to the uranium by the lixiviant

  17. Improving hydrolysis of food waste in a leach bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Browne, James D.; Allen, Eoin; Murphy, Jerry D., E-mail: jerry.murphy@ucc.ie

    2013-11-15

    Highlights: • This paper assesses leaching of food waste in a two phase digestion system. • Leaching is assessed with and without an upflow anaerobic sludge blanket (UASB). • Without the UASB, low pH reduces hydrolysis, while increased flows increase leaching. • Inclusion of the UASB increases pH to optimal levels and greatly improves leaching. • The optimal conditions are suggested as low flow with connection to the UASB. - Abstract: This paper examines the rate of degradation of food waste in a leach bed reactor (LBR) under four different operating conditions. The effects of leachate recirculation at a low and high flow rate are examined with and without connection to an upflow anaerobic sludge blanket (UASB). Two dilution rates of the effective volume of the leach bed reactors were investigated: 1 and 6 dilutions per LBR per day. The increase in dilution rate from 1 to 6 improved the destruction of volatile solids without connection to the UASB. However connection to the UASB greatly improved the destruction of volatile solids (by almost 60%) at the low recirculation rate of 1 dilution per day. The increase in volatile solids destruction with connection to the UASB was attributed to an increase in leachate pH and buffering capacity provided by recirculated effluent from the UASB to the leach beds. The destruction of volatile solids for both the low and high dilution rates was similar with connection to the UASB, giving 82% and 88% volatile solids destruction respectively. This suggests that the most efficient leaching condition is 1 dilution per day with connection to the UASB.

  18. Full-scale leaching study of commercial reactor waste forms

    International Nuclear Information System (INIS)

    Kalb, P.D.; Colombo, P.

    1984-01-01

    This paper describes a full-scale leaching experiment which has been conducted at Brookhaven National Laboratory (BNL) to study the release of radionuclides from actual commercial reactor waste forms. While many studies characterizing the leaching behavior of simulated laboratory-scale waste forms have been performed, this program represents one of the first attempts in the United States to quantify activity releases for real, full-scale waste forms. 5 references, 5 figures, 1 table

  19. Alkaline leaching of coal by the mechanochemical treatment

    Directory of Open Access Journals (Sweden)

    Turèániová ¼udmila

    1998-09-01

    Full Text Available The possibility of application of a new process GACL (Grinding and Aqueous Caustic Leaching for the reduction of mineral components in the brown coal Nováky was tested. The simultaneous grinding and chemical leaching enable us to extract 41 % total sulphur, 95 % arsenic and to reduce the ash content to 43 %. The process proceeds at the atmospheric pressure, temperature 90oC and in diluted NaOH solutions (5 %.

  20. Heavy metal leaching from mine tailings as affected by plants

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, D.; Schwab, A.P.; Banks, M.K.

    1999-12-01

    A column experiment was conducted to determine the impact of soil cover and plants on heavy metal leaching from mine tailings and heavy metal contaminated soil. Columns made of PVC were constructed with 30 cm subsoil covered by 30 cm of mine tailings followed by 0, 30, or 60 cm subsoil covered by 30 cm of mine tailings followed by 0, 30, or 60 cm of clean topsoil. Two grasses, tall fescue (Festuca arundinacea Schreb.) and big bluestem (Andropogon gerardii), were grown in the columns. The columns were leached at a slow rate for 1 yr with a 0.001 M CaCl{sub 2} solution under unsaturated conditions. The presence of both tall fescue and big bluestem increased Zn and Cd concentrations in the leachate. Lead concentrations in leachates were not affected by the presence of plants. Although plants generally reduced the total amount of water leached, total mass of Zn and Cd leached generally was not impacted by plants. Total mass of Pb leached was positively correlated with total leachate collected from each column. Covering the mine tailings with 60 cm of topsoil increased the mass of Zn and Cd leached relative to no topsoil. When the subsoil was absent, Zn and Cd leaching increased by as much as 20-fold, verifying the ability of soil to act as a sink for metals. Mine tailing remediation by establishing vegetation can reduce Pb movement but may enhance short-term Cd and Zn leaching. However, the changes were relatively small and do not outweigh the benefits of using vegetation in mine tailings reclamation.

  1. Leaching Properties of Naturally Occurring Heavy Metals from Soils

    Science.gov (United States)

    Zhang, M.; Hoshino, M.; Yoshikawa, M.; Hara, J.; Sugita, H.

    2014-12-01

    The major threats to human health from heavy metals are associated with exposure to arsenic, lead, cadmium, chromium, mercury, as well as some other elements. The effects of such heavy metals on human health have been extensively studied and reviewed by international organizations such as WHO. Due to their toxicity, heavy metal contaminations have been regulated by national environmental standards in many countries, and/or laws such as the Soil Contamination Countermeasures Act in Japan. Leaching of naturally occurring heavy metals from the soils, especially those around abandoned metal mines into surrounding water systems, either groundwater or surface water systems, is one of the major pathways of exposure. Therefore, understanding the leaching properties of toxic heavy metals from naturally polluted soils is of fundamentally importance for effectively managing abandoned metal mines, excavated rocks discharged from infrastructure constructions such as tunneling, and/or selecting a pertinent countermeasure against pollution when it is necessary. In this study, soil samples taken from the surroundings of abandoned metal mines in different regions in Japan were collected and analyzed. The samples contained multiple heavy metals such as lead, arsenic and chromium. Standard leaching test and sequential leaching test considering different forms of contaminants, such as trivalent and pentavalent arsenics, and trivalent and hexavalent chromiums, together with standard test for evaluating total concentration, X-ray Fluorescence Analysis (XRF), X-ray diffraction analysis (XRD) and Cation Exchange Capacity (CEC) tests were performed. In addition, sequential leaching tests were performed to evaluate long-term leaching properties of lead from representative samples. This presentation introduces the details of the above experimental study, discusses the relationships among leaching properties and chemical and mineral compositions, indicates the difficulties associated with

  2. Stainless Steel Leaches Nickel and Chromium into Foods During Cooking

    OpenAIRE

    Kamerud, Kristin L.; Hobbie, Kevin A.; Anderson, Kim A.

    2013-01-01

    Toxicological studies show that oral doses of nickel and chromium can cause cutaneous adverse reactions such as dermatitis. Additional dietary sources, such as leaching from stainless steel cookware during food preparation, are not well characterized. This study examined stainless steel grades, cooking time, repetitive cooking cycles, and multiple types of tomato sauces for their effects on nickel and chromium leaching. Trials included three types of stainless steels and a stainless steel sau...

  3. Improving hydrolysis of food waste in a leach bed reactor

    International Nuclear Information System (INIS)

    Browne, James D.; Allen, Eoin; Murphy, Jerry D.

    2013-01-01

    Highlights: • This paper assesses leaching of food waste in a two phase digestion system. • Leaching is assessed with and without an upflow anaerobic sludge blanket (UASB). • Without the UASB, low pH reduces hydrolysis, while increased flows increase leaching. • Inclusion of the UASB increases pH to optimal levels and greatly improves leaching. • The optimal conditions are suggested as low flow with connection to the UASB. - Abstract: This paper examines the rate of degradation of food waste in a leach bed reactor (LBR) under four different operating conditions. The effects of leachate recirculation at a low and high flow rate are examined with and without connection to an upflow anaerobic sludge blanket (UASB). Two dilution rates of the effective volume of the leach bed reactors were investigated: 1 and 6 dilutions per LBR per day. The increase in dilution rate from 1 to 6 improved the destruction of volatile solids without connection to the UASB. However connection to the UASB greatly improved the destruction of volatile solids (by almost 60%) at the low recirculation rate of 1 dilution per day. The increase in volatile solids destruction with connection to the UASB was attributed to an increase in leachate pH and buffering capacity provided by recirculated effluent from the UASB to the leach beds. The destruction of volatile solids for both the low and high dilution rates was similar with connection to the UASB, giving 82% and 88% volatile solids destruction respectively. This suggests that the most efficient leaching condition is 1 dilution per day with connection to the UASB

  4. Cement based grouts - longevity laboratory studies: leaching behaviour

    International Nuclear Information System (INIS)

    Onofrei, M.; Gray, M.; Roe, L.

    1991-12-01

    This report describes a series of laboratory tests carried out to determine the possible leaching behaviour of cement-based grouts in repository environments. A reference high-performance cement-based grout, comprised of Canadian Type 50 (U.S. Type V) Sulphate Resisting Portland Cement, silica fume, potable water and superplasticizer, and a commercially available cement grout were subjected to leaching in distilled water and three simulated groundwaters of different ionic strength. Hardened, monolithic specimens of the grout were leached in static, pulsed-flow and continuous flow conditions at temperatures from 10 degrees C to 150 degrees C for periods of up to 56 days. The changes in concentration of ions in the leachants with time were determined and the changes in the morphology of the surfaces of the grout specimens were examined using electron microscopy. After a review of possible mechanisms of degradation of cement-based materials, the data from these experiments are presented. The data show that the grouts will leach when in contact with water through dissolution of more soluble phases. Comparison of the leaching performance of the two grouts indicates that, while there are some minor differences, they behaved quite similarly. The rate of the leaching processes were found to tend to decrease with time and to be accompanied by precipitation and/or growth of an assemblage of secondary alteration phases (i.e., CaCO 3 , Mg(OH) 2 ). The mechanisms of leaching depended on the environmental conditions of temperature, groundwater composition and water flow rate. Matrix dissolution occurred. However, in many of the tests leaching was shown to be limited by the precipitated/reaction layers which acted as protective surface coatings. (37 refs.) (au)

  5. Steady-state leaching of tritiated water from silica gel

    DEFF Research Database (Denmark)

    Das, H.A.; Hou, Xiaolin

    2009-01-01

    Aqueous leaching of tritium from silica gel, loaded by absorption of water vapor, makes part of reactor de-commissioning. It is found to follow the formulation of steady-state diffusion.......Aqueous leaching of tritium from silica gel, loaded by absorption of water vapor, makes part of reactor de-commissioning. It is found to follow the formulation of steady-state diffusion....

  6. Leach rate characterization of solid radioactive waste forms

    International Nuclear Information System (INIS)

    Flynn, K.F.; Barletta, R.E.; Jardine, L.J.; Steindler, M.J.

    1978-01-01

    Leach rates were measured using distilled water on four types of waste forms: spray calcined waste mixed with silica and borosilicate glass and sintered, the same pulverized, the same in a lead matrix, and waste glass containing U. Twenty isotopes ranging from 22 Na to 239 Np were measured using activation analysis. Leach rates were also measured for a variety of matrix materials (Zircaloy, Al, Pb, glass, Pb 3 RE 6 (SiO 4 ) 6 ), using one isotope each. 2 tables

  7. Mathematical modelling in leaching studies of radioactive waste

    International Nuclear Information System (INIS)

    Plecas, I.; Pavlovic, R.; Pavlovic, S.

    2001-01-01

    Transport phenomena involved in the leaching of a radioactive material from a composite matrix into surrounding water are investigated using three methods based on theoretical equations. These arc: diffusion equation derived for a plane source model, rate equation for diffusion coupled with a first-order reaction and an empirical method employing a polynomial equation. The obtained results are compared with respect to their applicability to the 60 Co and 137 Cs leaching data. (author)

  8. Carbonate heap leach of uranium-contaminated soils

    International Nuclear Information System (INIS)

    Turney, W.R.; Mason, C.F.V.; Longmire, P.

    1994-01-01

    A new approach to removal of uranium from soils based on existing heap leach mining technologies proved highly effective for remediation of soils from the Fernald Environmental Management Project (FEMP) near Cincinnati, Ohio. In laboratory tests, remediation of uranium-contaminated soils by heap leaching with carbonate salt solutions was demonstrated in column experiments. An understanding of the chemical processes that occur during carbonate leach of uranium from soils may lead to enhancement of uranium removal. Carbonate leaching requires the use of an integrated and closed circuit process, wherein the leach solutions are recycled and the reagents are reused, resulting in a minimum secondary waste stream. Carbonate salt leach solution has two important roles. Primarily, the formation of highly soluble anionic carbonate uranyl species, including uranyl dicarbonate (UO 2 CO 32 = ) and uranyl tricarbonate (UO 2 CO 33 4- ), allows for high concentration of uranium in a leachate solution. Secondly, carbonate salts are nearly selective for dissolution of uranium from uranium contaminated soils. Other advantages of the carbonate leaching process include (1) the high solubility, (2) the selectivity, (3) the purity of the solution produced, (4) the relative ease with which a uranium product can be precipitated directly from the leachate solution, and (5) the relatively non-corrosive and safe handling characteristics of carbonate solutions. Experiments conducted in the laboratory have demonstrated the effectiveness of carbonate leach. Efficiencies of uranium removal from the soils have been as high as 92 percent. Higher molar strength carbonate solutions (∼0.5M) proved more effective than lower molar strength solutions (∼ 0.1M). Uranium removal is also a function of lixiviant loading rate. Furthermore, agglomeration of the soils with cement resulted in less effective uranium removal

  9. Nutrient leaching under zero tension in a subtropical clonal eucalypt ...

    African Journals Online (AJOL)

    Little is known about the effects of residue burning or retention on nutrient leaching during the inter-rotation of clonal Eucalyptus grown on the sandy soils of subtropical Zululand, South Africa. A study compared zero-tension nutrient leaching through the top metre of soil at depths of 0.15, 0.5 and 1.0 m in an undisturbed crop ...

  10. Method for evaluating leaching from LSA-III material

    International Nuclear Information System (INIS)

    Abe, H.; Satoh, K.; Ozaki, S.; Watabe, N.; Iida, T.; Akamatsu, H.

    1989-01-01

    The IAEA transport regulations are scheduled to be introduced in Japan. New regulations are supposed to be set forth for low specific activity (LSA) material and industrial packaging (IP) as solidified concentrated waste water should correspond to the LSA material. Solidified concentrated waste water should be transported in accordance with the new transport regulations which reflect the IAEA transport regulations. As one of the regulations for LSA material, the leaching test for LSA-III materials states that the radioactive loss due to leaching without the packaging should not exceed 0.1 A 2 when left in the water for 7 days. This test method is called Transport regulations hereafter. Since the test had not been conducted in Japan before now, there was no available data. Consequently, it is necessary to make an assessment on whether the current solidified concentrated waste water can satisfy the leaching amount of radioactive nuclide specified in the IAEA transport regulations. If the test is performed in accordance with the IAEA transport regulations, however, it is necessary to measure the amount of radioactive nuclide actually leached from the solidified concentrated waste water. Since the solidified concentrated waste water is put in a drum cam, it is necessary to prepare large-scale hot test equipment. In this study, therefore, the leaching test was conducted on the solidified concentrated waste water to propose the means of a leaching assessment which can be conducted with ordinary equipment to evaluate the leaching for assessment of the adaptability to IAEA transport regulations. In addition, the leaching test was performed in accordance with the IAEA method to examine the co-relation between the transport regulations and the IAEA method. Many test results have been reported for the IAEA method in Japan, which will be detailed later on

  11. Indirect Calorimetry in Mechanically Ventilated Patients

    DEFF Research Database (Denmark)

    Allingstrup, Matilde Jo; Kondrup, Jens; Perner, Anders

    2017-01-01

    Background and Aims: The 2 currently available indirect calorimeters, CCM Express Indirect Calorimeter (MedGraphics, St Paul, MN) and Quark RMR ICU Indirect Calorimeter (COSMED, Rome, Italy), have not been validated against a gold standard in mechanically ventilated patients. Our aim was to do so...... using a gold-standard, modified Tissot bell-spirometer method in mechanically ventilated patients who were hemodynamically, respiratory, and metabolically stable. Methods: We studied 30 patients undergoing general anesthesia and major gynecological surgery. We measured oxygen consumption ((Formula...... of 77 (167) with limits of agreement −249 to 404 kcal/d. Conclusions: The QUARK RMR ICU Indirect Calorimeter compared better with the gold standard for values of (Formula presented.) O2 and REE than did the CCM Express Indirect Calorimeter in mechanically ventilated patients who were circulatory...

  12. HEPA filter leaching concept validation trials at the Idaho Chemical Processing Plant

    International Nuclear Information System (INIS)

    Chakravartty, A.C.

    1995-04-01

    The enclosed report documents six New Waste Calcining Facility (NWCF) HEPA filter leaching trials conducted at the Idaho Chemical Processing Plant using a filter leaching system to validate the filter leaching treatment concept. The test results show that a modified filter leaching system will be able to successfully remove both hazardous and radiological constituents to RCRA disposal levels. Based on the success of the filter leach trials, the existing leaching system will be modified to provide a safe, simple, effective, and operationally flexible filter leaching system

  13. Stability and leaching of cobalt smelter fly ash

    DEFF Research Database (Denmark)

    Vítková, Martina; Hyks, Jiri; Ettler, Vojtěch

    2013-01-01

    The leaching behaviour of fly ash from a Co smelter situated in the Zambian Copperbelt was studied as a function of pH (5–12) using the pH-static leaching test (CEN/TS 14997). Various experimental time intervals (48h and 168h) were evaluated. The leaching results were combined with the ORCHESTRA...... modelling framework and a detailed mineralogical investigation was performed on the original FA and leached solid residues. The largest amounts of Co, Cu, Pb and Zn were leached at pH 5, generally with the lowest concentrations between pH 9 and 11 and slightly increased concentrations at pH 12. For most...... detected using SEM/EDS and/or TEM/EDS. The leaching of metals was mainly attributed to the dissolution of metallic particles. Partial dissolution of silicate and glass fractions was assumed to significantly influence the release of Ca, Mg, Fe, K, Al and Si as well as Cu, Co and Zn. The formation of illite...

  14. Leaching of Conductive Species: Implications to Measurements of Electrical Resistivity.

    Science.gov (United States)

    Spragg, R; Jones, S; Bu, Y; Lu, Y; Bentz, D; Snyder, K; Weiss, J

    2017-05-01

    Electrical tests have been used to characterize the microstructure of porous materials, the measured electrical response being determined by the contribution of the microstructure (porosity and tortuosity) and the electrical properties of the solution (conductivity of the pore solution) inside the pores of the material. This study has shown how differences in concentration between the pore solution (i.e., the solution in the pores) and the storage solution surrounding the test specimen leads to significant transport (leaching) of the conductive ionic species between the pore solution and the storage solution. Leaching influences the resistivity of the pore solution, thereby influencing electrical measurements on the bulk material from either a surface or uniaxial bulk resistance test. This paper has three main conclusions: 1.) Leaching of conductive species does occur with concentration gradients and that a diffusion based approach can be used to estimate the time scale associated with this change. 2.) Leaching of ions in the pore solution can influence resistivity measurements, and the ratio of surface to uniaxial resistivity can be used as a method to assess the presence of leaching and 3.) An estimation of the magnitude of leaching for standardized tests of cementitious materials.

  15. Leaching of Added Selenium in Soils Low in Native Selenium

    DEFF Research Database (Denmark)

    Nielsen, Gunnar Gissel; Hamdy, A. A.

    1977-01-01

    A soil column experiment was performed to evaluate the influence of organic matter and lime on the leaching and distribution of added selenite. 75Se-labeled Na2SeO3 was added to water-saturated soil columns with a diameter of 4.25 cm and a length of 16-20 cm. Leaching started immediately, one l...... water being added per column during the course of 1 wk. Most of the selenite did not move through the soil, and only a few per cent were found in the leaching water. Leaching was greatest in sandy soil. It was increased by the addition of lime, but decreased by addition of organic matter. Most...... of the leaching took place within the 1st few days. In other experiments, selenite fixation in soils took several days to reach equilibrium. Leaching of the selenite added to mineral soils under Danish field conditions was insignificant in the short time-cycle of Se in the environment....

  16. Presence and leaching of bisphenol a (BPA) from dental materials

    Science.gov (United States)

    Becher, Rune; Wellendorf, Hanne; Sakhi, Amrit Kaur; Samuelsen, Jan Tore; Thomsen, Cathrine; Bølling, Anette Kocbach; Kopperud, Hilde Molvig

    2018-01-01

    Abstract BPA has been reported to leach from some resin based dental restorative materials and materials used for orthodontic treatment. To confirm and update previous findings, especially in light of the new temporary lower threshold value for tolerable daily BPA intake, we have investigated the leaching of BPA from 4 composite filling materials, 3 sealants and 2 orthodontic bonding materials. The materials were either uncured and dissolved in methanol or cured. The cured materials were kept in deionized water for 24 hours or 2 weeks. Samples were subsequently analyzed by ultra-performance liquid chromatography coupled to mass spectrometry (UPLC-MS-MS). The composite filling material Tetric EvoFlow® and the fissure sealant DELTON® showed significantly higher levels of BPA leaching compared to control samples for all test conditions (uncured, 24 h leaching and 2 weeks leaching). There were no significant differences in amount of leached BPA for any of the tested materials after 24 hours compared to 2 weeks. These results show that BPA is still released from some dental materials despite the general concern about potential adverse effects of BPA. However, the amounts of BPA were relatively low and most likely represent a very small contribution to the total BPA exposure. PMID:29868625

  17. Estimating Leaching Requirements for Barley Growth under Saline Irrigation

    Directory of Open Access Journals (Sweden)

    Ahmed Al-Busaidi

    2012-01-01

    Full Text Available The utilization of marginal water resources for agriculture is receiving considerable attention. The lands irrigated with saline water are required to reduce salt accumulations through leaching and/or drainage practices. A field experiment was carried out to investigate the effect of saline irrigation and leaching fraction on barley (Hordeum vulgare L. growth. For this purpose highly saline water was diluted to the salinity levels of 3, 6 and 9 dS m-1 and applied by drip irrigation at 0.0, 0.15, 0.20 and 0.25 leaching fractions (LF. The results of the experiment showed that both quantity and quality of water regulated salts distribution within the soil in the following manner: a the salts were found higher near or immediate below the soil surface; b an enhanced LF carried more salts down the soil horizon but there was no significant difference in plant yield between different treatments of leaching fractions. Salinity of water significantly impaired barley growth. The good drainage of sandy soil enhanced the leaching process and minimized the differences between leaching fractions. The increment in saline treatments (3, 6 and 9 dS m-1 added more salts and stressed plant growth. However, the conjunctive use of marginal water at proportional LF could be effective in enhancing the yield potential of crops in water-scarce areas.

  18. Renewal of corrosion progress after long-term leaching

    International Nuclear Information System (INIS)

    Muller, I.

    1997-01-01

    Over the past 18 years a large inventory of glasses which have undergone leach testing has been built up at the Vitreous State Laboratory of The Catholic University of America. These glasses include a very wide range of compositions, most from actual mixed wastes and many natural analogs. A variety in the test protocol have been used, including PCT, ANSI, TCLP, IAEA, Flow, Soxhlet, MCC1, MCC3, and DIN. Many of these tests have been conducted for over a decade and are still ongoing. The progress of the tests is monitored by periodic sampling with fluid replacement. Twenty different leachants (including groundwaters, humic acid and pH buffers) have been employed. Occasionally, some of the glass is removed from the leaching vessels to observe the altered layers forming on the glass and to identify reaction products. Slight variations in the composition of the glass, subjected to PCT leaching, exhibit widely differing leaching behaviors. The evolution of leachate composition over time often shows a basically stable leach rate followed by a dramatic increase, with times of onset varying considerably, primarily as a function of glass composition. The same rapid rise in leachate has also been observe for a given glass composition studied at different S/V ratio. The study of such non-linearity in glass leaching is the subject of this review. (author)

  19. Biocide leaching during field experiments on treated articles.

    Science.gov (United States)

    Schoknecht, Ute; Mathies, Helena; Wegner, Robby

    2016-01-01

    Biocidal products can be sources of active substances in surface waters caused by weathering of treated articles. Marketing and use of biocidal products can be limited according to the European Biocidal Products Regulation if unacceptable risks to the environment are expected. Leaching of active substances from treated articles was observed in field experiments to obtain information on leaching processes and investigate the suitability of a proposed test method. Leaching under weathering conditions proceeds discontinuously and tends to decrease with duration of exposure. It does not only mainly depend on the availability of water but is also controlled by transport processes within the materials and stability of the observed substances. Runoff amount proved to be a suitable basis to compare results from different experiments. Concentrations of substances are higher in runoff collected from vertical surfaces compared to horizontal ones, whereas the leached amounts per surface area are higher from horizontal surfaces. Gaps in mass balances indicate that additional processes such as degradation and evaporation may be relevant to the fate of active substances in treated articles. Leached amounts of substances were considerably higher when the materials were exposed to intermittent water contact under laboratory conditions as compared to weathering of vertically exposed surfaces. Experiences from the field experiments were used to define parameters of a procedure that is now provided to fulfil the requirements of the Biocidal Products Regulation. The experiments confirmed that the amount of water which is in contact with exposed surfaces is the crucial parameter determining leaching of substances.

  20. Pesticide leaching through sandy and loamy fields e Long-term lessons learnt from the Danish Pesticide Leaching Assessment Programme

    DEFF Research Database (Denmark)

    Rosenbom, Annette Elisabeth; Olsen, Preben; Plauborg, Finn

    2015-01-01

    The European Union authorization procedure for pesticides includes assessment of the leaching risk posed by pesticides and their degradation products aimed at avoiding any unacceptable influence on the environment, in particular contamination of water, including drinking water and groundwater...

  1. Leaching behavior of microtektite glass compositions in sea water and the effect of precipitation on glass leaching

    International Nuclear Information System (INIS)

    1991-01-01

    In the present study it was attempted to account for the slow corrosion rates of microtektite glass in nature by comparing the leach rates of synthetic microtektite glass samples in deionized water and in sea-water, respectively. In order to obtain systematic data about leachant composition effects, leach tests were also carried out with synthetic leachant compositions enriched with respect to silica or depleted with respect to certain major components of sea-water (Mg, Ca). 47 refs., 1 fig., 5 tabs

  2. Column leaching experiments of a uranium ore by atomizing irrigation technique

    International Nuclear Information System (INIS)

    Zeng Yingying; Lei Zeyong; Chen Haihui

    2007-01-01

    Column leaching experiments ora uranium ore were made by atomizing irrigation technique. The leaching results are compared with the results obtained by spray irrigation and drip irrigation techniques respectively under the same conditions of column leaching experiments. The results show that the atomizing irrigation technique has more uniform solution distribution, higher leaching rate, shorter leaching period, and less ratio of liquid to solid. Consequently, the atomizing irrigation technique is suitable to the ore. (authors)

  3. Ball Milling Treatment of Black Dross for Selective Dissolution of Alumina in Sodium Hydroxide Leaching

    OpenAIRE

    Thi Thuy Nhi Nguyen; Man Seung Lee; Thi Hong Nguyen

    2018-01-01

    A process consisting of ball milling followed by NaOH leaching was developed to selectively dissolve alumina from black dross. From the ball milling treatment, it was found that milling speed greatly affected the leaching behavior of silica and the oxides of Ca, Fe, Mg, and Ti present in dross. The leaching behavior of the mechanically activated dross was investigated by varying NaOH concentration, leaching temperature and time, and pulp density. In most of the leaching conditions, only alumi...

  4. Leaching from waste incineration bottom ashes treated in a rotary kiln

    DEFF Research Database (Denmark)

    Hyks, Jiri; Nesterov, Igor; Mogensen, Erhardt

    2011-01-01

    Leaching from municipal solid waste incineration bottom ash treated in a rotary kiln was quantified using a combination of lab-scale leaching experiments and geochemical modelling. Thermal treatment in the rotary kiln had no significant effect on the leaching of Al, Ba, Ca, Mg, Si, Sr, Zn, sulfate...... the thermal treatment. Overall, rotary kiln thermal treatment of bottom ashes can be recommended to reduce the leaching of Cu, Pb, Cl and DOC; however, increased leaching of Cr and Mo should be expected....

  5. Single-pass continuous-flow leach test of PNL 76-68 glass: some selected Bead Leach I results

    International Nuclear Information System (INIS)

    Coles, D.G.

    1981-01-01

    A single-pass continuous-flow leach test of PNL 76-68 glass beads (7 mm dia) was concluded after 420 days of uninterrupted operation. Variables included in the experimental matrix were flow-rate, leachant composition, and temperature. Analysis was conducted on all leachate samples for 237 Np and 239 Pu as well as a number of nonradioactive elements. Results indicated that flow-rate and leachant systematically affected the leach rate, but only slightly. Temperature effects were significant. Plutonium leach rate was lower at higher temperature suggesting that Pu sorption onto the beads was enhanced at the higher temperature. The range of leach rates for all analyzed elements (except Pu), at both temperature, at all three flow rates, and with all three leachant compositions varied only three orders of magnitude. The range of variables used in this experiment covered those expected in many proposed repository environments. The preliminary interpretation of the results also indicated that matrix dissolution may be the dominant leaching mechanism, at least for Np in bicarbonate leachant. Regardless of the leaching mechanism the importance of this study is that it bounds the effects of repository environments when the ground water is oxidizing and when it doesn't reach the waste form until the waste has cooled to ambient rock temperature

  6. Expression of future prospective in indirect speech

    Directory of Open Access Journals (Sweden)

    Bodnaruk Elena Vladimirovna

    2015-03-01

    Full Text Available The article analyzes the characteristics and use of grammatical semantics and lexical and grammatical means used to create future prospects in double indirect discourse. The material for the study were epic works by contemporary German writers. In the analysis of the empirical material it has been pointed out that indirect discourse has preterial basis and is the kind of most frequent inner speech of characters. The most widely used form with future semantics in preterial indirect speech is conditional I, formally having a conjunctive basis, but is mostly used with the indicative semantics. Competitive to conditional I in indirect speech is preterial indicative. A characteristic feature of the indirect speech is the use of modal verbs, which, thanks to its semantics is usually referred as an action at a later term, creating the prospect of future statements. The most frequent were modal verbs wollen and sollen in the form of the preterite, more rare verbs were m ssen and k nnen. German indirect speech distinguishes the ability to use forms on the basis of conjunctive: preterite and plusquamperfect of conjunctive. Both forms express values similar to those of the indicative. However, conjunctive forms the basis of the data shown in a slightly more pronounced seme of uncertainty that accompanies future uses of these forms in indirect speech. In addition, plusquamperfect conjunctive differs from others by the presence of the seme of completeness.

  7. Direct separation of uranium and thorium from Qatrani phosphatic raw ore by consecutive percolation leaching

    Energy Technology Data Exchange (ETDEWEB)

    Hussein El-Sayed, M

    1984-07-01

    Phosphatic sandstone of Qatrani area contains high concentrations of uranium and thorium (1450 and 870 ppm respectively). These elements were directly separated from a representative sample of the ore by percolation leaching. Separation made was carried out by using two different leaching reagents, citric and nitric acids for obtaining two separate concentrates of U and Th consecutively from the sample. Uranium was leached first by using citric acid where other rock ingredients were left intact. The effects of: (a) increasing acid input amounts and (b) increasing leaching solution volumes (dilution) on U leaching efficiency were studied. The results revealed that citric acid reaction upon phosphate is limited in spite of higher residual acidity reported in the leach liquors. Regarding uranium, its leaching efficiency increased by increasing acid amounts and/or leaching solution volumes while fixing the acid input amounts. The efficiency of U leaching is more pronounced in the second case than in the first. Increasing U leaching while phosphate dissolution is limited could be interpreted as that the relative complexing affinity of citrate anion for hexavalent uranium is by far much greater than with phosphate. Thorium was thereafter leached by using dilute solutions of nitric acid to avoid dissolution of nitric acid to avoid dissolution of impurities. Percolation leaching experiments were thus performed on the uranium-free samples in the columns used previously in uranium leaching. The effects of increasing acid amounts and increasing leach liquor recycles on Th (and P/sub 2/O/sub 5/) leaching efficiency were studied.

  8. Optimization of aspergillus niger nutritional conditions using statistical experimental methods for bio-recovery of manganese from pyrolusite

    International Nuclear Information System (INIS)

    Mujeeb-ur-Rahman; Yasinzai, M.M.; Tareen, R.B.; Iqbal, A.; Gul, S.; Odhano, E.A.

    2011-01-01

    Optimization of aspergillus niger nutritional conditions using statistical experimental methods for bio-recovery of manganese from pyrolusite Mujeeb-ur-rahman, Mohammed Masoom Yasinzai, Rasool Bakhsh Tareen, Asim Iqbal, Ejaz Ali Odhano, Shereen Gul. The nutritional requirements for Aspergillus niger PCSIR-06 for bio-recovery of manganese from pyrolusite ore were optimized. Box-Bhenken design and response surface methodology were used for designing of experiment and statistical analysis of the results. This procedure limited the number of actual experiments to 54 for studying the possible interaction between six nutrients. The optimum concentration of the nutrients were Sucrose 148.5 g/L, KH/sub 2/PO/sub 4/ 0.50 g/L, NH/sub 4/NO/sub 3/ 0.33 g/L, MgSO/sub 4/ 0.41 g/L, Zn 23.76 mg/L, Fe 0.18 mg/L for Aspergillus niger to achieve maximum bio-recovery of manganese (82.47 +- 5.67%). The verification run confirmed the predicted optimized concentration of all the six ingredients for maximum bio leaching of manganese and successfully confirmed the use of Box-Bhenken experimental design for maximum bio-recovery. Results also revealed that small and less time consuming experimental designs could be efficient for optimization of bio-recovery processes. (author)

  9. Evaluation of the antifungal effects of bio-oil prepared with lignocellulosic biomass using fast pyrolysis technology.

    Science.gov (United States)

    Kim, Kwang Ho; Jeong, Han Seob; Kim, Jae-Young; Han, Gyu Seong; Choi, In-Gyu; Choi, Joon Weon

    2012-10-01

    This study was performed to investigate the utility of bio-oil, produced via a fast pyrolysis process, as an antifungal agent against wood-rot fungi. Bio-oil solutions (25-100 wt.%) were prepared by diluting the bio-oil with EtOH. Wood block samples (yellow poplar and pitch pine) were treated with diluted bio-oil solutions and then subjected to a leaching process under hot water (70°C) for 72 h. After the wood block samples were thoroughly dried, they were subjected to a soil block test using Tyromyces palustris and Trametes versicolor. The antifungal effect of the 75% and 100% bio-oil solutions was the highest for both wood blocks. Scanning electron microscopy analysis indicated that some chemical components in the bio-oil solution could agglomerate together to form clusters in the inner part of the wood during the drying process, which could act as a wood preservative against fungal growth. According to GC/MS analysis, the components of the agglomerate were mainly phenolic compounds derived from lignin polymers. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Bio-inspired vision

    International Nuclear Information System (INIS)

    Posch, C

    2012-01-01

    Nature still outperforms the most powerful computers in routine functions involving perception, sensing and actuation like vision, audition, and motion control, and is, most strikingly, orders of magnitude more energy-efficient than its artificial competitors. The reasons for the superior performance of biological systems are subject to diverse investigations, but it is clear that the form of hardware and the style of computation in nervous systems are fundamentally different from what is used in artificial synchronous information processing systems. Very generally speaking, biological neural systems rely on a large number of relatively simple, slow and unreliable processing elements and obtain performance and robustness from a massively parallel principle of operation and a high level of redundancy where the failure of single elements usually does not induce any observable system performance degradation. In the late 1980's, Carver Mead demonstrated that silicon VLSI technology can be employed in implementing ''neuromorphic'' circuits that mimic neural functions and fabricating building blocks that work like their biological role models. Neuromorphic systems, as the biological systems they model, are adaptive, fault-tolerant and scalable, and process information using energy-efficient, asynchronous, event-driven methods. In this paper, some basics of neuromorphic electronic engineering and its impact on recent developments in optical sensing and artificial vision are presented. It is demonstrated that bio-inspired vision systems have the potential to outperform conventional, frame-based vision acquisition and processing systems in many application fields and to establish new benchmarks in terms of redundancy suppression/data compression, dynamic range, temporal resolution and power efficiency to realize advanced functionality like 3D vision, object tracking, motor control, visual feedback loops, etc. in real-time. It is argued that future artificial vision systems

  11. Indirect estimators in US federal programs

    CERN Document Server

    1996-01-01

    In 1991, a subcommittee of the Federal Committee on Statistical Methodology met to document the use of indirect estimators - that is, estimators which use data drawn from a domain or time different from the domain or time for which an estimate is required. This volume comprises the eight reports which describe the use of indirect estimators and they are based on case studies from a variety of federal programs. As a result, many researchers will find this book provides a valuable survey of how indirect estimators are used in practice and which addresses some of the pitfalls of these methods.

  12. Bio-oil fractionation and condensation

    Science.gov (United States)

    Brown, Robert C; Jones, Samuel T; Pollard, Anthony

    2013-07-02

    A method of fractionating bio-oil vapors which involves providing bio-oil vapors comprising bio-oil constituents is described. The bio-oil vapors are cooled in a first stage which comprises a condenser having passages for the bio-oil separated by a heat conducting wall from passages for a coolant. The coolant in the condenser of the first stage is maintained at a substantially constant temperature, set at a temperature in the range of 75 to 100.degree. C., to condense a first liquid fraction of liquefied bio-oil constituents in the condenser of the first stage. The first liquid fraction of liquified bio-oil constituents from the condenser in the first stage is collected. Also described are steps for subsequently recovering further liquid fractions of liquefied bio-oil constituents. Particular compositions of bio-oil condensation products are also described.

  13. Statistical comparison of leaching behavior of incineration bottom ash using seawater and deionized water: Significant findings based on several leaching methods.

    Science.gov (United States)

    Yin, Ke; Dou, Xiaomin; Ren, Fei; Chan, Wei-Ping; Chang, Victor Wei-Chung

    2018-02-15

    Bottom ashes generated from municipal solid waste incineration have gained increasing popularity as alternative construction materials, however, they contains elevated heavy metals posing a challenge for its free usage. Different leaching methods are developed to quantify leaching potential of incineration bottom ashes meanwhile guide its environmentally friendly application. Yet, there are diverse IBA applications while the in situ environment is always complicated, challenging its legislation. In this study, leaching tests were conveyed using batch and column leaching methods with seawater as opposed to deionized water, to unveil the metal leaching potential of IBA subjected to salty environment, which is commonly encountered when using IBA in land reclamation yet not well understood. Statistical analysis for different leaching methods suggested disparate performance between seawater and deionized water primarily ascribed to ionic strength. Impacts of leachant are metal-specific dependent on leaching methods and have a function of intrinsic characteristics of incineration bottom ashes. Leaching performances were further compared on additional perspectives, e.g. leaching approach and liquid to solid ratio, indicating sophisticated leaching potentials dominated by combined geochemistry. It is necessary to develop application-oriented leaching methods with corresponding leaching criteria to preclude discriminations between different applications, e.g., terrestrial applications vs. land reclamation. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. A two-step leaching method designed based on chemical fraction distribution of the heavy metals for selective leaching of Cd, Zn, Cu, and Pb from metallurgical sludge.

    Science.gov (United States)

    Wang, Fen; Yu, Junxia; Xiong, Wanli; Xu, Yuanlai; Chi, Ru-An

    2018-01-01

    For selective leaching and highly effective recovery of heavy metals from a metallurgical sludge, a two-step leaching method was designed based on the distribution analysis of the chemical fractions of the loaded heavy metal. Hydrochloric acid (HCl) was used as a leaching agent in the first step to leach the relatively labile heavy metals and then ethylenediamine tetraacetic acid (EDTA) was applied to leach the residual metals according to their different fractional distribution. Using the two-step leaching method, 82.89% of Cd, 55.73% of Zn, 10.85% of Cu, and 0.25% of Pb were leached in the first step by 0.7 M HCl at a contact time of 240 min, and the leaching efficiencies for Cd, Zn, Cu, and Pb were elevated up to 99.76, 91.41, 71.85, and 94.06%, by subsequent treatment with 0.2 M EDTA at 480 min, respectively. Furthermore, HCl leaching induced fractional redistribution, which might increase the mobility of the remaining metals and then facilitate the following metal removal by EDTA. The facilitation was further confirmed by the comparison to the one-step leaching method with single HCl or single EDTA, respectively. These results suggested that the designed two-step leaching method by HCl and EDTA could be used for selective leaching and effective recovery of heavy metals from the metallurgical sludge or heavy metal-contaminated solid media.

  15. Impact of aging on leaching characteristics of recycled concrete aggregate.

    Science.gov (United States)

    Abbaspour, Aiyoub; Tanyu, Burak F; Cetin, Bora

    2016-10-01

    The focus of this study was to evaluate the effects of stockpiling (aging) on leaching of elements in recycled concrete aggregate (RCA) that may contribute to tufaceous constituent formation. Speciation and leaching controlling mechanisms of these elements were identified via geochemical modeling. The effects of stockpiling were simulated by comparing freshly produced RCA with RCA aged as part of this study for 1 year both in the laboratory and in the field. Leachate samples were generated following batch water leach test (WLT) and US Geological Survey leach test (USGSLT) methods. USGSLTs were conducted both on the laboratory and field samples while WLT was only conducted on laboratory samples. During the laboratory aging, it is observed that the carbonate content of RCA, measured as calcite equivalent, increased 20 % (i.e., from ∼100 to 120 mg/g) within a year time frame. The leachate extracted from RCA showed minor changes in pH and more significant decreases in electrical conductivity (i.e., ∼300 to 100 μS/cm). A comparison between laboratory and field samples revealed that the RCA aged much slower in the field than in the laboratory within a year. Comparisons between two leach extraction methods on the laboratory conditions showed that the total leached concentrations (TLCs) of most of the constituents from USGSLT were appreciably lower than the ones measured via WLT method. The results of geochemical modeling analyses showed that Al, Si, Fe, Ca, Mg, and Cu exist in their oxidized forms as Al 3+ , Fe 3+ , Si 4+ , Ca 2+ , Mg 2+ , and Cu 2+ and results revealed that these elements are primarily controlled by the solubility of gibbsite, hematite, silica gel, calcite, magnesite, and tenorite solid phases, respectively. One of the significant findings of the study was to identify the changes in leaching behavior of Ca, Si, Mg, Al, Fe, and Cu due to carbonation.

  16. Acid leaching of mixed spent Li-ion batteries

    Directory of Open Access Journals (Sweden)

    A.A. Nayl

    2017-05-01

    Full Text Available Acid leaching for different types of mixed spent Li-ion mobile batteries is carried out after alkali decomposition using NH4OH followed by H2SO4 + H2O2 leaching. In the alkali decomposition step, the effects of reaction time, NH4OH concentration, liquid/solid mass ratio and reaction temperature on the decomposition process are investigated to remove Al, Cu, Mn, Ni, Co, and Li. After alkaline treatment, the alkali paste is treated to leach the remaining metals using H2SO4 + H2O2. The significant effects of reaction time, acid concentration, H2O2 concentration, liquid/solid mass ratios and reaction temperature on the leaching rate are studied. More than 97% of Al, Mn, Ni, Co, and Li and about 65% Cu are leached in two stages. Kinetic analysis shows that, the data fit with chemical reaction control mechanism and the activation energies for the investigated metals using the Arrhenius equation ranged from 30.1 to 41.4 kJ/mol. Recovered metals are precipitated from the leaching liquor at varying pH values using NaOH solution and Na2CO3. Firstly, Mn is precipitated as MnCO3 at pH = 7.5. Secondly, at pH = 9.0, nickel is precipitated as NiCO3. Thirdly, as the pH of the leaching liquor reaches 11–12, Co(OH2 is precipitated and the remaining Li is readily precipitated as Li2CO3 using a saturated Na2CO3 solution. Based on the experimental data, a flow sheet is developed and tested for the recovery process.

  17. Kinetics of the Carbonate Leaching for Calcium Metavanadate

    Directory of Open Access Journals (Sweden)

    Peiyang Shi

    2016-10-01

    Full Text Available The sodium salt roasting process was widely used for extracting vanadium due to its high yield rate of vanadium. However, the serious pollution was a problem. The calcium roasting process was environmentally friendly, but the yield rate of vanadium was relatively lower. Focusing on the calcium metavanadate produced in the calcium roasting process of vanadium minerals, the mechanism of the carbonate leaching for calcium metavanadate and its leaching kinetics of calcium metavanadate were studied. With the increase of the leaching agent content, the decrease of the particle size, the increase of the temperature and the increase of the reaction time, the leaching rate of vanadium increased, and the constant of reaction rate increased. In the carbonate leaching process, the calcium carbonate was globular and attached to the surface of calcium metavanadate. In the solution containing bicarbonate radical, lots of cracks formed in the dissolution process. However, the cracks were relatively fewer in the solution containing carbonate. In the present study, the carbonate leaching for calcium metavanadate was controlled by diffusion, the activation energy reached maximum and minimum in the sodium bicarbonate and the sodium carbonate solution, respectively. The activation energy value in the ammonium bicarbonate solution was between those two solutions. The kinetic equations of the carbonate leaching for calcium metavanadate were as follows: 1 − 2/3η − (1 − η2/3 = 4.39[Na2CO3]0.75/r0 × exp(−2527.06/Tt; 1 − 2/3η − (1 − η2/3 = 7.89[NaHCO3]0.53/r0 × exp(−2530.67/Tt; 1 − 2/3η − (1 − η2/3 = 6.78[NH4HCO3]0.69/r0 × exp(−2459.71/Tt.

  18. Recycling of spent lithium-ion battery cathode materials by ammoniacal leaching

    International Nuclear Information System (INIS)

    Ku, Heesuk; Jung, Yeojin; Jo, Minsang; Park, Sanghyuk; Kim, Sookyung; Yang, Donghyo; Rhee, Kangin; An, Eung-Mo; Sohn, Jeongsoo; Kwon, Kyungjung

    2016-01-01

    Highlights: • Ammoniacal leaching is used to recover spent Li-ion battery cathode materials. • Leaching agents consist of ammonia, ammonium sulfite and ammonium carbonate. • Ammonium sulfite is a reductant and ammonium carbonate acts as pH buffer. • Co and Cu can be fully leached while Mn and Al are not leached. • Co recovery via ammoniacal leaching is economical compared to acid leaching. - Abstract: As the production and consumption of lithium ion batteries (LIBs) increase, the recycling of spent LIBs appears inevitable from an environmental, economic and health viewpoint. The leaching behavior of Ni, Mn, Co, Al and Cu from treated cathode active materials, which are separated from a commercial LIB pack in hybrid electric vehicles, is investigated with ammoniacal leaching agents based on ammonia, ammonium carbonate and ammonium sulfite. Ammonium sulfite as a reductant is necessary to enhance leaching kinetics particularly in the ammoniacal leaching of Ni and Co. Ammonium carbonate can act as a pH buffer so that the pH of leaching solution changes little during leaching. Co and Cu can be fully leached out whereas Mn and Al are hardly leached and Ni shows a moderate leaching efficiency. It is confirmed that the cathode active materials are a composite of LiMn_2O_4, LiCo_xMn_yNi_zO_2_, Al_2O_3 and C while the leach residue is composed of LiNi_xMn_yCo_zO_2, LiMn_2O_4, Al_2O_3, MnCO_3 and Mn oxides. Co recovery via the ammoniacal leaching is believed to gain a competitive edge on convenitonal acid leaching both by reducing the sodium hydroxide expense for increasing the pH of leaching solution and by removing the separation steps of Mn and Al.

  19. Research on the effect of alkali roasting of copper dross on leaching rate of indium

    Science.gov (United States)

    Dafang, Liu; Fan, Xingxiang; Shi, Yifeng; Yang, Kunbin

    2017-11-01

    The byproduct copper dross produced during refining crude lead was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and fluorescence spectrometer (XRF), which showed that copper dross mainly contained lead, copper, zinc, arsenic, antimony, bismuth, sulfur and a small amount of indium and silver etc. The mineralogical phase change of oxidation roasting of copper dross by adding sodium hydroxide was analyzed with the help of XRD and SEM. The effects of water leaching, ratio of sodium hydroxide, roasting time, and roasting temperature on leaching rate of indium were investigated mainly. The experimental results showed that phase of lead metal and sulfides of lead, copper and zinc disappeared after oxidation roasting of copper dross by adding sodium hydroxide, new phase of oxides of lead, copper, zinc and sodium salt of arsenic and antimony appeared. Water leaching could remove arsenic, and acid leaching residue obtained was then leached with acid. The leaching rate of indium was higher 6.98% compared with alkali roasting of copper dross-acid leaching. It showed that removing arsenic by water leaching and acid leaching could increase the leaching rate of indium and be beneficial to reducing subsequent acid consumption of extracting indium by acid leaching. The roasting temperature had a significant effect on the leaching rate of indium, and leaching rate of indium increased with the rise of roasting temperature. When roasting temperature ranged from 450°C to 600°C, leaching rate of indium increased significantly with the rise of roasting temperature. When roasting temperature rose from 450°C to 600°C, leaching rate of indium increased by 60.29%. The amount of sodium hydroxide had an significant effect on the leaching rate of indium, and the leaching of indium increased with the increase of the amount of sodium hydroxide, and the leaching rate of indium was obviously higher than that of copper dross blank roasting and acid leaching.

  20. Bioelectrochemical Systems for Indirect Biohydrogen Production

    KAUST Repository

    Regan, John M.; Yan, Hengjing

    2014-01-01

    by exoelectrogens at the anode. As an indirect approach to biohydrogen production, these systems are not subject to the hydrogen yield constraints of fermentative processes and have been proven to work with virtually any biodegradable organic substrate

  1. BioAir: Bio-Inspired Airborne Infrastructure Reconfiguration

    Science.gov (United States)

    2016-01-01

    must also minimize resource usage due to limitations on the amount of processing , memory and power onboard a node. BioAIR assumes the availability of...subsequent maintenance of tentacles, each node will take one of the following roles: “ orphan ”, “free”, “tip”, “backbone” or “extra”. The BioAIR...algorithm dictates that when a node is disconnected from the tentacle or origin it is an orphan , and as such it will change its target to the nearest

  2. Indirect techniques in nuclear astrophysics: a review

    International Nuclear Information System (INIS)

    Tribble, R E; Mukhamedzhanov, A M; Bertulani, C A; Cognata, M La; Spitaleri, C

    2014-01-01

    In this review, we discuss the present status of three indirect techniques that are used to determine reaction rates for stellar burning processes, asymptotic normalization coefficients, the Trojan Horse method and Coulomb dissociation. A comprehensive review of the theory behind each of these techniques is presented. This is followed by an overview of the experiments that have been carried out using these indirect approaches. (review article)

  3. Bottle roll leach test for Temrezli uranium ore

    International Nuclear Information System (INIS)

    Çetin, K.; Bayrak, M.; Turan, A. İsbir; Üçgül, E.

    2014-01-01

    The bottle roll leach test is one of the dynamic leaching procedure which can meet in-situ mining needs for determining suitable working conditions and helps to simulate one of the important parameter; injection well design. In this test, the most important parameters are pulp density, acidic or basic concentration of leach solution, time and temperature. In recent years, bottle roll test is used not only for uranium but also gold, silver, copper and nickel metals where in situ leach (ISL) mining is going to be applied. For this purpose for gold and silver metal cyanide bottle roll tests and for uranium metal; acidic and basic bottle roll tests could be applied. The new leach test procedure which is held in General Directorate of Mineral Research and Exploration (MTA) of Turkey is mostly suitable for determining metal extraction conditions and recovery values in uranium containing ore bodies. The tests were conducted with samples taken from Temrezli Uranium Ore located in approximately 200 km east of Turkey’s capital, Ankara. Mining rights of Temrezli Ore is controlled 100% by Anatolia Energy Ltd. The resource estimate includes an indicated mineral resource of 10.827 Mlbs U_3O_8 [~4160 t U] at an average grade of 1426 ppm [~1210 ppm U] and an additional inferred resource of 6.587 Mlbs of U_3O_8 [~2530 t U] at an average grade of 904 ppm [~767 ppm U]. In accordance with the demand from Anatolia Energy bottle roll leach tests have been initiated in MTA laboratories to investigate the recovery values of low-grade uranium ore under in-situ leach conditions. Bottle roll leaching tests are performed on pulverized samples with representative lixiviant solution at ambient pressure and provide an initial evaluation of ore leachability with a rough estimate of recovery value. At the end of the tests by using 2 g/L NaHCO_3 and 0.2 g/L H_2O_2 more than 90% of uranium can pass into leach solution in 12 days. (author)

  4. Resistance evaluation expanded perlite the leaching acid: variation of parameters concentration, time and leaching agent

    International Nuclear Information System (INIS)

    Almeida, J.M.F. de; Damasceno Junior, E.; Oliveira, E.S.; Fernandes, N.S.

    2016-01-01

    The expanded perlite is an amorphous aluminosilicate which presents in its composition about 75.0% silicon oxide (SiO2), also having other species in the composition as oxides of some metals. Silicas and silicates have been used in the environmental field, in relevant anti-corrosive activity. In this context, materials that exposes too many highly acidic media, require preservation against this type of wear, as this type of damage causes a great financial loss, thereby requiring low-cost, abundant materials, non-toxic and easy to purchase as some silica coating. The study evaluated the perlite expanded resistance against an acid leaching process. With undeniability the use of strong acids and different working conditions were not able to remove the oxides present on the expanded perlite sample, thus demonstrating the high strength of the expanded perlite against acid attacks. (author)

  5. An Indirect Route for Ethanol Production

    Energy Technology Data Exchange (ETDEWEB)

    Eggeman, T.; Verser, D.; Weber, E.

    2005-04-29

    The ZeaChem indirect method is a radically new approach to producing fuel ethanol from renewable resources. Sugar and syngas processing platforms are combined in a novel way that allows all fractions of biomass feedstocks (e.g. carbohydrates, lignins, etc.) to contribute their energy directly into the ethanol product via fermentation and hydrogen based chemical process technologies. The goals of this project were: (1) Collect engineering data necessary for scale-up of the indirect route for ethanol production, and (2) Produce process and economic models to guide the development effort. Both goals were successfully accomplished. The projected economics of the Base Case developed in this work are comparable to today's corn based ethanol technology. Sensitivity analysis shows that significant improvements in economics for the indirect route would result if a biomass feedstock rather that starch hydrolyzate were used as the carbohydrate source. The energy ratio, defined as the ratio of green energy produced divided by the amount of fossil energy consumed, is projected to be 3.11 to 12.32 for the indirect route depending upon the details of implementation. Conventional technology has an energy ratio of 1.34, thus the indirect route will have a significant environmental advantage over today's technology. Energy savings of 7.48 trillion Btu/yr will result when 100 MMgal/yr (neat) of ethanol capacity via the indirect route is placed on-line by the year 2010.

  6. Pollution potential leaching index as a tool to assess water leaching risk of arsenic in excavated urban soils.

    Science.gov (United States)

    Li, Jining; Kosugi, Tomoya; Riya, Shohei; Hashimoto, Yohey; Hou, Hong; Terada, Akihiko; Hosomi, Masaaki

    2018-01-01

    Leaching of hazardous trace elements from excavated urban soils during construction of cities has received considerable attention in recent years in Japan. A new concept, the pollution potential leaching index (PPLI), was applied to assess the risk of arsenic (As) leaching from excavated soils. Sequential leaching tests (SLT) with two liquid-to-solid (L/S) ratios (10 and 20Lkg -1 ) were conducted to determine the PPLI values, which represent the critical cumulative L/S ratios at which the average As concentrations in the cumulative leachates are reduced to critical values (10 or 5µgL -1 ). Two models (a logarithmic function model and an empirical two-site first-order leaching model) were compared to estimate the PPLI values. The fractionations of As before and after SLT were extracted according to a five-step sequential extraction procedure. Ten alkaline excavated soils were obtained from different construction projects in Japan. Although their total As contents were low (from 6.75 to 79.4mgkg -1 ), the As leaching was not negligible. Different L/S ratios at each step of the SLT had little influence on the cumulative As release or PPLI values. Experimentally determined PPLI values were in agreement with those from model estimations. A five-step SLT with an L/S of 10Lkg -1 at each step, combined with a logarithmic function fitting was suggested for the easy estimation of PPLI. Results of the sequential extraction procedure showed that large portions of more labile As fractions (non-specifically and specifically sorbed fractions) were removed during long-term leaching and so were small, but non-negligible, portions of strongly bound As fractions. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Roasting and leaching behaviors of vanadium and chromium in calcification roasting-acid leaching of high-chromium vanadium slag

    Science.gov (United States)

    Wen, Jing; Jiang, Tao; Zhou, Mi; Gao, Hui-yang; Liu, Jia-yi; Xue, Xiang-xin

    2018-05-01

    Calcification roasting-acid leaching of high-chromium vanadium slag (HCVS) was conducted to elucidate the roasting and leaching behaviors of vanadium and chromium. The effects of the purity of CaO, molar ratio between CaO and V2O5 ( n(CaO)/ n(V2O5)), roasting temperature, holding time, and the heating rate used in the oxidation-calcification processes were investigated. The roasting process and mechanism were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetry-differential scanning calorimetry (TG-DSC). The results show that most of vanadium reacted with CaO to generate calcium vanadates and transferred into the leaching liquid, whereas almost all of the chromium remained in the leaching residue in the form of (Fe0.6Cr0.4)2O3. Variation trends of the vanadium and chromium leaching ratios were always opposite because of the competitive reactions of oxidation and calcification between vanadium and chromium with CaO. Moreover, CaO was more likely to combine with vanadium, as further confirmed by thermodynamic analysis. When the HCVS with CaO added in an n(CaO)/ n(V2O5) ratio of 0.5 was roasted in an air atmosphere at a heating rate of 10°C/min from room temperature to 950°C and maintained at this temperature for 60 min, the leaching ratios of vanadium and chromium reached 91.14% and 0.49%, respectively; thus, efficient extraction of vanadium from HCVS was achieved and the leaching residue could be used as a new raw material for the extraction of chromium. Furthermore, the oxidation and calcification reactions of the spinel phases occurred at 592 and 630°C for n(CaO)/ n(V2O5) ratios of 0.5 and 5, respectively.

  8. Leaching behavior of various low-level waste solids

    International Nuclear Information System (INIS)

    Ito, Akihiko; Ouchi, Yasuyoshi; Matsuzuru, Hideo; Wadachi, Yoshiki

    1985-01-01

    This report deals with the leaching of radioactive nuclides from low-level wastes solidified with cement, bitumen or plastics. Considerations are made on the effects of type of solidification matrix and waste; type, amount and exchange frequency of leachate; type and conditions of embedding soil; temperature and pressure; and secular deterioration. It is assumed that a waste composite is entirely immersed in leachate and that the amount of the leachate is large compared to the surface area of the waste. Cement solid is characterized by its high alkalinity and porosity while plastic and bitumen solids are dense and neutral. The content of waste in a composite is low for cement and high for plastics. It is generally high in bitumen solid though it should be reduced if the solid is likely to bulge. The leaching of 137 Cs from cement solid is slightly dependent on the waste-cement ratio while it increases with increasing waste content in the case of plastic or bitumen solid. For 60 Co, the leaching from cement solid depends on the alkalinity of the cement material used though it is not affected by the waste-cement ratio. In the case of plastics and bitumen, on the other hand, the pH value of the waste have some effects on the leaching of 60 Co; the leaching decreases with increasing pH. (Nogami, K.)

  9. Leaching and geochemical behavior of fired bricks containing coal wastes.

    Science.gov (United States)

    Taha, Yassine; Benzaazoua, Mostafa; Edahbi, Mohamed; Mansori, Mohammed; Hakkou, Rachid

    2018-03-01

    High amounts of mine wastes are continuously produced by the mining industry all over the world. Recycling possibility of some wastes in fired brick making has been investigated and showed promising results. However, little attention is given to the leaching behavior of mine wastes based fired bricks. The objective of this paper is to evaluate the geochemical behavior of fired bricks containing different types of coal wastes. The leachates were analyzed for their concentration of As, Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, Zn and sulfates using different leaching tests; namely Tank Leaching tests (NEN 7375), Toxicity Characteristic Leaching Procedure (TCLP) and pH dependence test (EPA, 1313). The results showed that the release of constituents of potential interest was highly reduced after thermal treatment and were immobilized within the glassy matrix of the fired bricks. Moreover, it was also highlighted that the final pH of all fired samples changed and stabilized around 8-8.5 when the initial pH of leaching solution was in the range 2.5-11.5. The release of heavy metals and metalloids (As) tended to decrease with the increase of pH from acidic to alkaline solutions while Mo displayed a different trend. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Stainless steel leaches nickel and chromium into foods during cooking.

    Science.gov (United States)

    Kamerud, Kristin L; Hobbie, Kevin A; Anderson, Kim A

    2013-10-02

    Toxicological studies show that oral doses of nickel and chromium can cause cutaneous adverse reactions such as dermatitis. Additional dietary sources, such as leaching from stainless steel cookware during food preparation, are not well characterized. This study examined stainless steel grades, cooking time, repetitive cooking cycles, and multiple types of tomato sauces for their effects on nickel and chromium leaching. Trials included three types of stainless steels and a stainless steel saucepan, cooking times of 2-20 h, 10 consecutive cooking cycles, and four commercial tomato sauces. After a simulated cooking process, samples were analyzed by ICP-MS for Ni and Cr. After 6 h of cooking, Ni and Cr concentrations in tomato sauce increased up to 26- and 7-fold, respectively, depending on the grade of stainless steel. Longer cooking durations resulted in additional increases in metal leaching, where Ni concentrations increased 34-fold and Cr increased approximately 35-fold from sauces cooked without stainless steel. Cooking with new stainless steel resulted in the largest increases. Metal leaching decreases with sequential cooking cycles and stabilized after the sixth cooking cycle, although significant metal contributions to foods were still observed. The tenth cooking cycle resulted in an average of 88 μg of Ni and 86 μg of Cr leached per 126 g serving of tomato sauce. Stainless steel cookware can be an overlooked source of nickel and chromium, where the contribution is dependent on stainless steel grade, cooking time, and cookware usage.

  11. Leaching of dissolved phosphorus from tile-drained agricultural areas.

    Science.gov (United States)

    Andersen, H E; Windolf, J; Kronvang, B

    2016-01-01

    We investigated leaching of dissolved phosphorus (P) from 45 tile-drains representing animal husbandry farms in all regions of Denmark. Leaching of P via tile-drains exhibits a high degree of spatial heterogeneity with a low concentration in the majority of tile-drains and few tile-drains (15% in our investigation) having high to very high concentration of dissolved P. The share of dissolved organic P (DOP) was high (up to 96%). Leaching of DOP has hitherto been a somewhat overlooked P loss pathway in Danish soils and the mechanisms of mobilization and transport of DOP needs more investigation. We found a high correlation between Olsen-P and water extractable P. Water extractable P is regarded as an indicator of risk of loss of dissolved P. Our findings indicate that Olsen-P, which is measured routinely in Danish agricultural soils, may be a useful proxy for the P leaching potential of soils. However, we found no straight-forward correlation between leaching potential of the top soil layer (expressed as either degree of P saturation, Olsen-P or water extractable P) and the measured concentration of dissolved P in the tile-drain. This underlines that not only the source of P but also the P loss pathway must be taken into account when evaluating the risk of P loss.

  12. Leaching studies of low-level radioactive waste forms

    International Nuclear Information System (INIS)

    Dayal, R.; Arora, H.; Clinton, J.C.; Milian, L.

    1985-01-01

    A research program has been under way at the Brookhaven National Laboratory to investigate the radionuclide release behavior of ion exchange bead resin waste solidified in Portland cement. An important aspect of this program is to develop and evaluate testing procedures and methodologies which enable the long-term performance evaluation of waste forms under simulated field conditions. Cesium and strontium release behavior using a range of testing procedures, including intermittent leachant flow conditions, has been investigated. For cyclic wet/dry leaching tests, extended dry periods tend to enhance the release of Cs and suppress the release of Sr. Under extended wet period leaching conditions, however, both Cs and Sr exhibit suppressed releases. In contrast, radionuclide releases observed under continuously saturated leaching conditions, as represented by conventional leaching tests, are significantly different. The relevance and aplicability of these laboratory data obtained under a wide range of leaching conditions to the performance evaluation of waste forms under anticipated field conditions is discussed. 12 refs., 9 figs., 3 tabs

  13. Stainless Steel Leaches Nickel and Chromium into Foods During Cooking

    Science.gov (United States)

    Kamerud, Kristin L.; Hobbie, Kevin A.; Anderson, Kim A.

    2014-01-01

    Toxicological studies show that oral doses of nickel and chromium can cause cutaneous adverse reactions such as dermatitis. Additional dietary sources, such as leaching from stainless steel cookware during food preparation, are not well characterized. This study examined stainless steel grades, cooking time, repetitive cooking cycles, and multiple types of tomato sauces for their effects on nickel and chromium leaching. Trials included three types of stainless steels and a stainless steel saucepan; cooking times of 2 to 20 hours, ten consecutive cooking cycles, and four commercial tomato sauces. After a simulated cooking process, samples were analyzed by ICP-MS for Ni and Cr. After six hours of cooking, Ni and Cr concentrations in tomato sauce increased up to 26- and 7-fold respectively, depending on the grade of stainless steel. Longer cooking durations resulted in additional increases in metal leaching, where Ni concentrations increased 34 fold and Cr increased approximately 35 fold from sauces cooked without stainless steel. Cooking with new stainless steel resulted in the largest increases. Metal leaching decreases with sequential cooking cycles and stabilized after the sixth cooking cycle, though significant metal contributions to foods were still observed. The tenth cooking cycle, resulted in an average of 88 μg of Ni and 86 μg of Cr leached per 126 g serving of tomato sauce. Stainless steel cookware can be an overlooked source of nickel and chromium, where the contribution is dependent on stainless steel grade, cooking time, and cookware usage. PMID:23984718

  14. Alkaline autoclave leaching of refractory uranium-thorium minerals

    International Nuclear Information System (INIS)

    Milani, S. A.; Sam, S.

    2011-01-01

    This paper deals with the study of an innovative method for processing the Oman placer ores by alkaline leaching in ball mill autoclaves, where grinding and leaching of the refractory minerals take place simultaneously. This was followed by the selective separation of thorium and uranium from lanthanides by autoclave leaching of the hydroxide cake with ammonium carbonate-bicarbonate solutions. The introduced method is based on the fact that thorium and uranium form soluble carbonate complexes with ammonium carbonate, while lanthanides form sparingly soluble double carbonates. It was found that a complete alkaline leaching of Oman placer ores (98.0 P ercent ) was attained at 150 and 175 d egree C within 2.5 and 2h, respectively. Oman placer ores leaching was intensified and accelerated in a ball mill autoclaves as a result of the grinding action of steel balls, removal of the hydroxide layer covering ores grains and the continuous contact of fresh ore grains with alkaline solution. The study of selective carbonate processing of hydroxide cake with ammonium carbonate-bicarbonate solutions on autoclave under pressure revealed that the complete thorium recovery (97.5 P ercent ) with uranium recovery (90.8 P ercent ) and their separation from the lanthanides were attained at 70-80 d egree C during l-2h. The extraction of lanthanides in carbonate solution was low and did not exceed 4.6 P ercent .

  15. Intensification Behavior of Mercury Ions on Gold Cyanide Leaching

    Directory of Open Access Journals (Sweden)

    Qiang Zhong

    2018-01-01

    Full Text Available Cyanidation is the main method used to extract gold from gold raw materials; however, a serious problem with this method is the low leaching rate. In order to improve gold leaching, the intensification behavior of mercury ions on gold cyanide leaching, for two types of materials, sulphide gold concentrate and oxide gold ore, was investigated. The results showed that mercury ions, with only a 10−5 M dosage, could significantly intensify leaching and gold recovery. The dissolution behavior of gold plate was also intensified by 10−5 M mercury ions. Microstructure analysis showed that mercury ions intensified the cyanidation corrosion of the gold surface, resulting in a loose structure, where a large number of deep ravines and raised particles were evident across the whole gold surface. The loose structure added contact surface between the gold and cyanide, and accelerated gold dissolution. Moreover, mercury ions obstructed the formation of insoluble products, such as AuCN, Au(OHCN, and Au(OHx, that lead to a passivation membrane on the gold surface, reducing contact between the gold and cyanide. These effects, brought about by mercury ions, change the structure and product of the gold surface during gold cyanidation and promote gold leaching.

  16. In situ leaching of uranium: Technical, environmental and economic aspects

    International Nuclear Information System (INIS)

    1989-01-01

    Within the framework of its activities in nuclear raw materials the International Atomic Energy Agency has convened a series of meetings to discuss various aspects of uranium ore processing technology, recovery of uranium from non-conventional resources and development of projects for the production of uranium concentrates including economic aspects. As part of this continuing effort to discuss and document important aspects of uranium production the IAEA convened a Technical Committee Meeting on Technical, Economic and Environmental Aspects of In-Situ Leaching. Although the use of this technique is limited by geological and economic constraints, it has a significant potential to produce uranium at competitive prices. This is especially important in the current uranium market which is mainly characterised by large inventories, excess production capability and low prices. This situation is not expected to last indefinitely but it is unlikely to change drastically in the next ten years or so. This Technical Committee Meeting was held in Vienna from 3 to 6 November 1987 with the attendance of 24 participants from 12 countries. Eight papers were presented. Technical sessions covered in-situ mining research, environmental and licensing aspects and restoration of leached orebodies; the technological status of in-situ leaching, the current status and future prospects of in-situ leaching of uranium in Member States, general aspects of planning and implementation of in-situ projects and the economics of in-situ leaching. Refs, figs and tabs

  17. Alkaline Leaching of Low Zinc Content Iron-Bearing Sludges

    Directory of Open Access Journals (Sweden)

    Gargul K.

    2016-03-01

    Full Text Available Various types of waste materials containing zinc (e.g. dusts and sludges from gas dedusting process are obtained in steel industry. The contents of Zn in these materials may vary considerably. Even a low concentration of zinc in recirculated products precludes their recycling in ferrous metallurgy aggregates. Long storage of this type of material can lead to contamination of soil and water by zinc compounds which can be leached out by acid rain, for example. This paper focuses on research involving alkaline leaching tests of low zinc content iron-bearing materials. These tests were preceded by the analysis of the elemental, phase and grain size composition, and analysis of the thermodynamic conditions of the leaching process. The main aim of research was to decrease the content of the zinc in the sludge to the level where it is suitable as an iron-bearing material for iron production (~1% Zn. Leaching at elevated temperatures (368 K, 60 min has led to a decrease in the zinc content in the sludge of about 66%. The research revealed that long hour leaching (298 K, 100 hours carried out at ambient temperatures caused a reduction in zinc content by 60% to the value of 1.15-1.2% Zn.

  18. Sulfur dioxide leaching of spent zinc-carbon-battery scrap

    Energy Technology Data Exchange (ETDEWEB)

    Avraamides, J.; Senanayake, G.; Clegg, R. [A.J. Parker Cooperative Research Centre for Hydrometallurgy, Murdoch University, Perth, WA 6150 (Australia)

    2006-09-22

    Zinc-carbon batteries, which contain around 20% zinc, 35% manganese oxides and 10% steel, are currently disposed after use as land fill or reprocessed to recover metals or oxides. Crushed material is subjected to magnetic separation followed by hydrometallurgical treatment of the non-magnetic material to recover zinc metal and manganese oxides. The leaching with 2M sulfuric acid in the presence of hydrogen peroxide recovers 93% Zn and 82% Mn at 25{sup o}C. Alkaline leaching with 6M NaOH recovers 80% zinc. The present study shows that over 90% zinc and manganese can be leached in 20-30min at 30{sup o}C using 0.1-1.0M sulfuric acid in the presence of sulfur dioxide. The iron extraction is sensitive to both acid concentration and sulfur dioxide flow rate. The effect of reagent concentration and particle size on the extraction of zinc, manganese and iron are reported. It is shown that the iron and manganese leaching follow a shrinking core kinetic model due to the formation of insoluble metal salts/oxides on the solid surface. This is supported by (i) the decrease in iron and manganese extraction from synthetic Fe(III)-Mn(IV)-Zn(II) oxide mixtures with increase in acid concentration from 1M to 2M, and (ii) the low iron dissolution and re-precipitation of dissolved manganese and zinc during prolonged leaching of battery scrap with low sulfur dioxide. (author)

  19. Leaching of saltstone: Laboratory and field testing and mathematical modeling

    International Nuclear Information System (INIS)

    Grant, M.W.; Langton, C.A.; Oblath, S.B.; Pepper, D.W.; Wallace, R.M.; Wilhite, E.L.; Yau, W.W.F.

    1987-01-01

    A low-level alkaline salt solution will be a byproduct in the processing of high-level waste at the Savannah River Plant (SRP). This solution will be incorporated into a wasteform, saltstone, and disposed of in surface vaults. Laboratory and field leach testing and mathematical modeling have demonstrated the predictability of contaminant release from cement wasteforms. Saltstone disposal in surface vaults will meet the design objective, which is to meet drinking water standards in shallow groundwater at the disposal area boundary. Diffusion is the predominant mechanism for release of contaminants to the environment. Leach testing in unsaturated soil, at soil moisture levels above 1 wt %, has shown no difference in leach rate compared to leaching in distilled water. Field leach testing of three thirty-ton blocks of saltstone in lysimeters has been underway since January 1984. Mathematical models were applied to assess design features for saltstone disposal. One dimensional infinite-composite and semi-infinite analytical models were developed for assessing diffusion of nitrate from saltstone through a cement barrier. Numerical models, both finite element and finite difference, were validated by comparison of model predictions with the saltstone lysimeter results. Validated models were used to assess the long-term performance of the saltstone stored in surface vaults. The maximum concentrations of all contaminants released from saltstone to shallow groundwater are predicted to be below drinking water standards at the disposal area boundary. 5 refs., 11 figs., 5 tabs

  20. The current status of glass leaching studies in France

    International Nuclear Information System (INIS)

    Laude, F.

    1983-11-01

    Glass has been selected in France as the material used to confine the activity of fission product solutions, and a continuous vitrification process has been developed at the Marcoule Vitrification Facility (AVM), the first industrial plant. Borosilicate glass was chosen in various compositions for its properties: it is a homogeneous, non-porous material that incorporates appreciable quantities of most of the fission product oxides, and is only alterable at the surface interface layer. Glass thus constitutes the primary radioactivity containment barrier, and it is essential to determine its long-term behavior. Water constitutes the principal hazard during temporary or definitive storage of the glass blocks. Two types of inherent material properties are studied from the standpoint of glass stability under leaching conditions: - chemical durability; - radioactive containability with regard to the various radionuclides, fission products and especially the actinides. Durability tests are carried out in SOXHLET devices and the alteration rates are measured by the weight loss. The containability is measured by the leach rate, i.e. by the rate of activity loss into the water. Leaching tests are conducted for several major objectives: - selection of glass compositions (leach rates); - leaching mechanism studies (hydrolyzed layer characteristics, effects of temperature, pressure, pH, etc.); - long-term behavior studies (glass specimens doped with alpha-emitters); - simulation of geological repository environments [fr

  1. Galvanic enhancement for high pressure leaching of chalcopyrite

    Directory of Open Access Journals (Sweden)

    Kim D.H.

    2016-01-01

    Full Text Available This study was conducted to evaluate the galvanic enhancement of the pressure oxidation (POX leaching of a chalcopyrite/chalcocite concentrate, which is believed to take place via a redox reaction. Cu recoveries of >90% could be achieved during POX leaching of this chalcopyrite/chalcocite concentrate at 200°C and 0.7 MPa initial oxygen pressure within 2h in a pressure reactor lined with titanium, which were 18-28% higher than for the same leaching using the teflon liner. A slow heating time seems to produce more sulphur coating, reducing the leaching performance, yielding much lower Cu recovery when the teflon lining was used, although this does not greatly affect the other case when the reactor was lined with titanium. The introduction of an electronic conductor, in this case the titanium surface, is believed to enhance this redox process, in which the oxidation of copper minerals and sulphur to sulphate at the anodic sites (mineral surface encountered during POX leaching takes place simultaneously with the reversible oxidation/reduction of the Fe2+/Fe3+couple and oxygen reduction on titanium.

  2. A case study of shrinkage-in place leaching of low grade uranium ore deposit

    International Nuclear Information System (INIS)

    Ding Dexin; Zhou Guohe

    1998-09-01

    A case study of shrinkage-in place leaching of low grade uranium ore deposit is dealt with. A test block was selected, and the shrinkage mining method was employed to construct the in place heap for leaching. Blast parameters and operations were carefully tried in order to make sure that the fragment size composition was adequate for leaching. A leaching system was planned and the corresponding leaching parameters were tried, too. The results show that the shrinkage method and the parameters for blasting and leaching are all adequate for the in-situ leaching of the blasted ore. This shrinkage-in place leaching system combines the mining and metallurgy processes into one and produces a lot of profits and could be applicable to many low grade uranium ore deposits which are so hard and compact that they have to be fragmented before being leached

  3. Study of radionuclide leaching from the residues of K Basin sludge dissolution

    International Nuclear Information System (INIS)

    Bechtold, D.B.

    1998-01-01

    The sludges remaining in the K Basins after removal of the spent N Reactor nuclear fuel will be conditioned for disposal. After conditioning, an acid-insoluble residue will remain that may require further leaching to properly condition it for disposal. This document presents a literature study to identify and recommend one or more chemical leaching treatments for laboratory testing, based on the likely compositions of the residues. The processes identified are a nitric acid cerate leach, a silver-catalyzed persulfate leach, a nitric hydrofluoric acid leach, an oxalic citric acid reactor decontamination leach, a nitric hydrochloric acid leach, a ammonium fluoride nitrate leach, and a HEOPA formate dehydesulfoxylate leach. All processes except the last two are recommended for testing in that order

  4. Ultrasound augmented leaching of nickel sulfate in sulfuric acid and hydrogen peroxide media.

    Science.gov (United States)

    Li, Haoyu; Li, Shiwei; Peng, Jinhui; Srinivasakannan, Chandrasekar; Zhang, Libo; Yin, Shaohua

    2018-01-01

    A new method of preparation high purity nickel sulfate assisted by ultrasonic was studied. The process mechanism was analyzed by Inductively Coupled Plasma (ICP), X-ray diffraction (XRD), Scanning electron microscopy (SEM), and Energy dispersive X-ray spectrometry (EDS).The reaction mechanisms of oxidizing leaching and ultrasonic leaching were explored, respectively. Results showed that ultrasonic treatment peel off the oxide film on the surface of nickel. The leachate under strongly agitated, the yield rate of nickel sulfate was accelerate. And the reaction area was increased by the cavitation effect, the liquid-solid reaction was promoted, and the activation energy was reduced. The leaching rate of nickel reached 46.29% by conventional leaching, which takes about 5h. Under the same conditions, the ultrasonic leaching rate reached 40%, only half of the conventional leaching time. Concentration of leaching agent, reaction temperature, ultrasonic power, leaching time had significant effect on the enhancement of the leaching reaction with ultrasonic radiation. The leaching rate of 60.41% under the optimum experiment conditions as follows: sulfuric acid concentration 30%, hydrogen peroxide 10%, leaching temperature 333K, ultrasonic power 200W and leaching time 4h. The kinetic study of the system was investigated, and the reaction rates of conventional leaching and ultrasonic leaching were controlled by diffusion, and the apparent activation energies were 16.2kJ/mol and 11.83kJ/mol. Copyright © 2017. Published by Elsevier B.V.

  5. From marine bio-corrosion to new bio-processes

    International Nuclear Information System (INIS)

    Bergel, A.; Dasilva, S.; Basseguy, R.; Feron, D.; Mollica, A.

    2004-01-01

    Full text of publication follows: From the middle of the last century it has been observed that the development of marine bio-films on the surface of stainless steels and different metallic materials induces the ennoblement of their free corrosion potential. A main step in deciphering the mechanisms of aerobic marine bio-corrosion has been achieved around 1976 with the demonstration that the potential ennoblement was due to the modification of the cathodic process. Since this date, the catalysis of oxygen reduction by marine bio-films has been the topic of numerous controversies, but it is now commonly agreed as a basic phenomena in aerobic corrosion. Several hypotheses have been proposed to explain the fine mechanisms of the bio-film-catalysed reduction of oxygen: intermediate formation of hydrogen peroxide, modification of the oxide layer on the stainless steel surface, involvement of manganese species and manganese oxidising bacteria, catalysis by proteins produced by the micro-organisms... Recent results may confirm the possible involvement of hemic enzymes or proteins. Whatever the mechanisms, very promising results have been obtained with the possible application of bio-film-catalysed oxygen reduction to conceive innovative biofuel cells with stainless steel electrodes. Actually, the catalysis of oxygen reduction is a key step that still drastically hinders the development of economically efficient hydrogen/oxygen fuel cells. The current technology requires high amounts of platinum or platinum-based materials to catalyze oxygen reduction on the cathode of these cells. The prohibitive cost of platinum is a main obstacle to the commercialization of low-cost fuel cells. Unpublished results recently showed that adapting the enzyme-catalysed reaction that was assumed for bio-corrosion on the cathode of hydrogen/oxygen fuel cells may lead to a significant decrease in the charge of platinum. Moreover, it was demonstrated on a laboratory-scale fuel cell pilot that

  6. Ferulaldehyde and lupeol as direct and indirect antimicrobial compounds from Cordia gilletii (Boraginaceae) root barks.

    Science.gov (United States)

    Okusa, Philippe N; Stévigny, Caroline; Névraumont, Marie; Gelbcke, Michel; Van Antwerpen, Pierre; Braekman, Jean Claude; Duez, Pierre

    2014-05-01

    Cordia gilletii De Wild (Boraginaceae), a medicinal plant used against infectious diseases in the Democratic Republic of Congo, was investigated for direct and indirect antimicrobial properties. On one hand, the methanol extract is active against many pathogenic bacteria, including resistant strains. Its bio-guided fractionation led to the isolation of ferulaldehyde; this compound showed antimicrobial and antioxidant properties that may support the activity we observed for the methanol extract and some of the traditional uses of C. gilletii. On the other hand, the n-hexane extract of root barks possesses indirect antimicrobial properties, enhancing the activity of antibiotics against methicillin-resistant Staphylococcus aureus (MRSA). The fractionation of this extract led to the isolation of lupeol, which decreases the minimum inhibitory concentration of several antibiotics (4 to 8 fold) against MRSA and contributes to the effects observed for the raw n-hexane extract.

  7. Evaluation of Emissions Bio diesel

    International Nuclear Information System (INIS)

    Rodriguez Maroto, J. J.; Dorronsoro Arenal, J. L.; Rojas Garcia, E.; Perez Pastor, R.; Garcia Alonso, S.

    2007-01-01

    The generation of energy from vegetal products is one of the possibilities to our reach in order to reduce the atmospheric pollution. Particularly, the use of bio diesel in internal combustion engines can be one of the best options. The finest particles emitted by the combustion engines are easily breathable and on them different substances can be absorbed presumably toxic, between which it is possible to emphasize the polycyclic aromatic hydrocarbons (PAHs), by its demonstrated carcinogen character. In this work, it is studied on the one hand, the characteristics that can present the aerosol of emission in a diesel engine with a maximum power of 97 kW, working without load to 600 rpm, using as combustible mixtures of bio diesel and diesel in different proportions. On the other hand, the evolution that takes place in the concentration of PAHs in emission particles, according to the percentage of bio diesel used in the combustible mixture. (Author) 9 refs

  8. Evaluation of Emissions Bio diesel

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Maroto, J J; Dorronsoro Arenal, J L; Rojas Garcia, E; Perez Pastor, R; Garcia Alonso, S

    2007-09-27

    The generation of energy from vegetal products is one of the possibilities to our reach in order to reduce the atmospheric pollution. Particularly, the use of bio diesel in internal combustion engines can be one of the best options. The finest particles emitted by the combustion engines are easily breathable and on them different substances can be absorbed presumably toxic, between which it is possible to emphasize the polycyclic aromatic hydrocarbons (PAHs), by its demonstrated carcinogen character. In this work, it is studied on the one hand, the characteristics that can present the aerosol of emission in a diesel engine with a maximum power of 97 kW, working without load to 600 rpm, using as combustible mixtures of bio diesel and diesel in different proportions. On the other hand, the evolution that takes place in the concentration of PAHs in emission particles, according to the percentage of bio diesel used in the combustible mixture. (Author) 9 refs.

  9. Bio-nanopatterning of Surfaces

    Directory of Open Access Journals (Sweden)

    Yeung Chun

    2007-01-01

    Full Text Available AbstractBio-nanopatterning of surfaces is a very active interdisciplinary field of research at the interface between biotechnology and nanotechnology. Precise patterning of biomolecules on surfaces with nanometre resolution has great potential in many medical and biological applications ranging from molecular diagnostics to advanced platforms for fundamental studies of molecular and cell biology. Bio-nanopatterning technology has advanced at a rapid pace in the last few years with a variety of patterning methodologies being developed for immobilising biomolecules such as DNA, peptides, proteins and viruses at the nanoscale on a broad range of substrates. In this review, the status of research and development are described, with particular focus on the recent advances on the use of nanolithographic techniques as tools for biomolecule immobilisation at the nanoscale. Present strengths and weaknesses, as well future challenges on the different nanolithographic bio-nanopatterning approaches are discussed.

  10. Influence of temperature on the fixation and penetration of silver during the chalcopyrite leaching using moderate thermophilic microorganisms

    International Nuclear Information System (INIS)

    Cancho, L.; Blazquez, M. L.; Munoz, J. A.; Gonzalez, F.; Ballester, A.

    2004-01-01

    Bio leaching of chalcopyrite using mesophilic microorganisms considerable improves in the presence of silver. However, the studies carried out with moderate thermophilic microorganisms do not show a significant improvement with regard to the use of mesophilic bacteria. The main objective of the present work has been to study the silver fixation on chalcopyrite ar 35 and 45 degree centigree and its influence on the microbiological attack. Different observations using SEM, EDS microanalysis and concentration profiles using electron microprobe have been carried out. The study of the different samples showed that silver fixation was more favourable at 35 degree centigree than at 45 degree centigree. In addition, bacterial action improved silver penetration through attack cracks. (Author)

  11. Contribution on the study of microbial effects on the leaching of radionuclides embedded in nuclear waste engineered barriers

    International Nuclear Information System (INIS)

    Spor, H.

    1994-05-01

    The aim of this work is to study the different interactions mechanisms between microorganisms and radioelements in conditions similar to those of a radioactive waste disposal site and to determine all the mechanisms due to microbial effects on the leaching of radionuclides embedded in nuclear waste engineered barriers. In this work are presented the different following points: - a bibliographic study on the microorganisms-radioelements interactions; - the conditions of metabolites production during the microbial growth (influence of the nature of the carbonated source, pH effects, aerobiosis conditions...); the mechanisms of a direct effect for determining the importance of the bio-sorption mechanism by microorganisms; the fact that the microbial biomass can strongly interact with actinides, heavy metals and radioelements; the effects of microorganisms on storage materials (cement and clay) containing radioelements (uranium, cesium); the complexation capacities of the organic and mineral acids produced during the microbial growth. (O.M.)

  12. Bio politics - The bio-environment - bio-culture of the Danube

    International Nuclear Information System (INIS)

    Vlavianos-Arvanitis, A.

    1997-01-01

    The bio-environment has been the single most important correlation in human history and can successfully promote international co-operational co-operation and understanding. With the construction of a network for collaboration, the 'Danube Countries' can come together in celebration of their culture and heritage. As the Danube flows from the Black Forest to the Black Sea, it carries messages of peace, hope and co-operation. Applying these messages to every endeavour can improve our quality of life and lead to a brighter future. Since its inception in 1985, the Bio politics International Organization (B.I.O.) has been labouring to raise awareness of the urgent need to instate a new system of norms and principles, compatible with sound environmental management and with the most important task of ensuring global literacy on environmental issues. Along with critically re-assessing the concept of profit, the goal is to adopt a system of bio centric values, where respect for the bio-environment will govern our every action and thought

  13. Assessment of weathering and leaching rates of Thule hot particles

    Energy Technology Data Exchange (ETDEWEB)

    Roos, P. (Technical Univ. of Denmark, Risoe National Laboratory for Sustainable Energy, Roskilde (Denmark)); Outola, I. (STUK-Radiation and Nuclear Safety Authority (Finland)); Nygren, U.; Ramebaeck, H. (FOI CBRN Defence and Security (Sweden)); Sidhu, R. (Institute of Energy Technology, Environmental Monitoring Section, Health and Safety Dept. (Norway))

    2010-03-15

    Within the current project a methodology for separating actinide particles originating from the Thule 1968 accident has been developed. Particles were completely isolated in water using visual and radiometric methods. The particles were attached electrostatic to a plastic support and could easily be moved to any container for leaching studies or other type of studies. Leaching and dissolution studies performed within the project indicate that some particles are relatively easily destroyed or leached while others are more refractory. The results shows that even though the oxide particles are hard to completely dissolve they release material even when exposed to weak solvents like water and salt solutions. Exposures to lung simulant fluids show relatively slow dissolution rates comparable to what is found using only water. Sequential extraction of particles shows that variation between particles is very large; some dissolve easily while some does not. Of radiological importance is the disruption of particles when exposed to dissolution. (author)

  14. Acid leaching of natural chrysotile asbestos to mesoporous silica fibers

    Science.gov (United States)

    Maletaškić, Jelena; Stanković, Nadežda; Daneu, Nina; Babić, Biljana; Stoiljković, Milovan; Yoshida, Katsumi; Matović, Branko

    2018-04-01

    Nanofibrous silica with a high surface area was produced from chrysotile by the acid-leaching method. Natural mineral chrysotile asbestos from Stragari, Korlace in Serbia was used as the starting material. The fibers were modified by chemical treatment with 1 M HCl and the mineral dissolution was monitored by transmission electron microscopy, X-ray powder diffraction, inductively coupled plasma spectrometry and low-temperature nitrogen adsorption techniques to highlight the effects of the leaching process. The results showed that the applied concentration of acid solution and processing time of 4 h were sufficient to effectively remove the magnesium hydroxide layer and transform the crystal structure of the hazardous starting chrysotile to porous SiO2 nanofibers. With prolonged acid leaching, the specific surface area, S BET, calculated by BET equation, was increased from 147 up to 435 m2 g- 1, with micropores representing a significant part of the specific surface.

  15. Water driven leaching of biocides from paints and renders

    DEFF Research Database (Denmark)

    Bester, Kai; Vollertsen, Jes; Bollmann, Ulla E

    ) were so high, that rather professional urban gardening (flower and greenhouses) than handling of biocides from construction materials seem to be able to explain the findings. While the use in agriculture is restricted, the use in greenhouses is currently considered legal in Denmark. Leaching....../partitioning: Considering material properties, it was found out that, for all of the compounds the sorption (and leaching) is highly pH-dependent. It must be take into account that the pH in the porewater of the tested render materials is between 9 and 10 while the rainwater is around 5, thus making prediction difficult...... at this stage. For some of the compounds the sorption is dependent on the amount of polymer in the render, while it is only rarely of importance which polymer is used. Considering the interaction of weather with the leaching of biocides from real walls it turned out that a lot of parameters such as irradiation...

  16. Characterization of dross and its recovery by sulphuric acid leaching

    Science.gov (United States)

    Rahmani, S. A.; Meidianto, A.; Amal, M. I.; Wismogroho, A. S.; Widayatno, W. B.

    2018-03-01

    This paper reports the characterization of dross from galvanizing process and its recovery using acidic leaching method. The diffraction profile of dross showed identical peaks with that of ZnO. The X-ray Fluorescence (XRF) analysis identified the content of following metals: Zn, Fe, Mn, Ga, Co, and W. The thermal behaviour examination revealed the existence of some volatiles within the initial sample. The acidic leaching at various concentrations of sulphuric acid was conducted to determine the optimum concentration for zinc recovery and the highest yield of zinc sulphate. It is concluded that the optimum concentration of H2SO4 for this kind of dross is 4 M with 71.9% yield of ZnSO4. The result of leaching process was confirmed by infrared spectrum, where various absorptions corresponding to SO4 2- and Zn-O bands were observed.

  17. Acid pre-treatment method for in situ ore leaching

    International Nuclear Information System (INIS)

    Mallon, R.G.; Braun, R.L.

    1975-01-01

    An acid leaching method is described for the recovery of a desired element from a subterranean rubblized body of primary ore containing the element and also having associated therewith a carbonate mineral wherein the rubblized ore body is flooded with an aqueous acidic solution in order to release carbon dioxide from the associated carbonate mineral. After a substantial portion of the available carbon dioxide is released and removed from the ore body, as by venting to the atmosphere, an oxidizing gas is introduced into the flooded, rubblized ore to oxidize the ore and form an acid leach solution effective in the presence of the dissolved oxidizing gas to dissolve the ore and cause the desired element to go into solution. The leach solution is then circulated to the surface where the metal values are recovered therefrom

  18. In situ leaching of uranium in South Australia

    International Nuclear Information System (INIS)

    Matthews, D.

    1998-01-01

    The proposed two new uranium mines at Beverley and Honeymoon, South Australia plan to use the cheap but potentially polluting process of in situ leaching (ISL) and permission has already been given for experimental underground leaching at Beverley. The mining industry describes ISL as environmentally benign because, instead of excavating, a corrosive liquid such as sulphuric acid is used. The liquid, sometimes 10000 times more acid than the aquifer water, is pumped into the ground in order to leach out the uranium and the resulting solution is then pumped to the surface where the uranium is extracted. Because the groundwater is salty and radioactive, the mining companies regard it as useless, so its contamination by ISL is considered of no concern. Salty radioactive water can be purified or desalinated and such processes are commonly used by mining companies such as Western Mining Corporation at Roxby Downs. (author)

  19. Leaching of radioactive nuclides from cement grouts. Part II

    International Nuclear Information System (INIS)

    Stanley, W.T.; Avgerinos, G.F.; Gonzalez, B.; Hemley, P.J.

    1974-01-01

    The determination of the leaching rate of radioactive 137 Cs from a cement grout should the grout be contacted by water is necessary for environmental protection. The effect of the leachant turnover rate on 137 Cs leaching rates was evaluated with batch and continuous (modified Soxhlet extractor) modes of experimentation. Three additives (Grundite, potter's clay, and Conasauga shale) were compared in terms of capability of radioactive isotope retention, while two leachants (tap and distilled water) were investigated. The Soxhlet extractor experiment resulted in the highest rate of leaching, and Conasauga shale was found the best additive for 137 Cs immobilization. Tap water used as leachant was more effective than distilled water. Data were analyzed using models involving isotopic diffusion in the grout and involving diffusion plus a time dependent boundary condition at the interface of grout specimen and leachant

  20. Study on gold concentrate leaching by iodine-iodide

    Science.gov (United States)

    Wang, Hai-xia; Sun, Chun-bao; Li, Shao-ying; Fu, Ping-feng; Song, Yu-guo; Li, Liang; Xie, Wen-qing

    2013-04-01

    Gold extraction by iodine-iodide solution is an effective and environment-friendly method. In this study, the method using iodine-iodide for gold leaching is proved feasible through thermodynamic calculation. At the same time, experiments on flotation gold concentrates were carried out and encouraging results were obtained. Through optimizing the technological conditions, the attained high gold leaching rate is more than 85%. The optimum process conditions at 25°C are shown as follows: the initial iodine concentration is 1.0%, the iodine-to-iodide mole ratio is 1:8, the solution pH value is 7, the liquid-to-solid mass ratio is 4:1, the leaching time is 4 h, the stirring intensity is 200 r/mim, and the hydrogen peroxide consumption is 1%.

  1. Leaching of assimilable silicon species from fly ash

    International Nuclear Information System (INIS)

    Piekos, R.; Paslawska, S.

    1998-01-01

    The objective of this study was to investigate the leaching of assimilable silicon species from coal fly ash with distilled water, sea waterand synthetic sea water at various fly ash/water ratios, pHs and temperatures. At the 1 g/100 ml fly ash/water ratio, less than 1 mg Si was found in 11 of aqueous slurries over the pH range 4-8 after 2 h at ambient temperature. The leaching was most effective at pH 10.5. At the fly ash/waterratio indicated, the pH of the suspensions decreased from 10.4 to 8.4 after 5days. The pH of fly ash slurries in sea water varied only slightly over time as compared with that in distilled water. Generally, the leaching of assimilable silicon species with distilled water was more intense than that with the sea water. 27 refs., 6 figs., 3 tabs

  2. BACTERIAL LEACHING OF ELECTRONIC SCRAP: INFLUENCE OF PROCESS PARAMETERS

    Directory of Open Access Journals (Sweden)

    Luciana Harue Yamane

    2013-03-01

    Full Text Available The application of bacterial leaching in the ore treatment is already known and also can be applied such as treatment of electronic waste to copper recovery. This paper investigates the influence of process parameters (pulp density, inoculums volume, rotation speed and initial concentration of ferrous iron on bacterial leaching of copper from printed circuit board of computers using the bacterium Acidithiobacillus ferrooxidans–LR. Printed circuit boards from computers were comminuted using a hammer mill. The powder obtained was magnetically separated and the non-magnetic material used in this study. A shake flask study was carried out on the non-magnetic material using a shaker. The results show that Acidithiobacillus ferrooxidans–LR can leach 99% of copper from printed circuit boards (non–magnetic material under the determined conditions through of the studies.

  3. Leaching studies on ion exchange resins immobilized in bitumen matrix

    International Nuclear Information System (INIS)

    Grosche Filho, C.E.; Chandra, U.; Villalobos, J.P.

    1986-01-01

    Many samples of bitumen mixed with ion exchange resin labelled with 134 Cs were prepared to study radionuclide leaching from bitumen waste forms. The resins used in tests were nuclear grade mixed cationic/aniocic bead resins. Different bitumen types were assayed: two distilled and two oxidized bitumens. Leached fractions were collected accordingly to the recommendation of ISO method, with complete exchange of leachant after each sampling. The volume collected for analysis was one liter. Marinelli beckers were used to improve counting efficiency in a Ge(Li) detector. The diffusion coefficients for samples prepared with distilled and oxidized bitumens were obtained. Mathematical models of transport phenomena applied to cylindrical geometry was employed to fit experimental data aiming to explain leaching mechanism and predict the long time behavior of immobilized radionuclides. (M.C.K.) [pt

  4. Assessment of weathering and leaching rates of Thule hot particles

    International Nuclear Information System (INIS)

    Roos, P.; Outola, I.; Nygren, U.; Ramebaeck, H.; Sidhu, R.

    2010-03-01

    Within the current project a methodology for separating actinide particles originating from the Thule 1968 accident has been developed. Particles were completely isolated in water using visual and radiometric methods. The particles were attached electrostatic to a plastic support and could easily be moved to any container for leaching studies or other type of studies. Leaching and dissolution studies performed within the project indicate that some particles are relatively easily destroyed or leached while others are more refractory. The results shows that even though the oxide particles are hard to completely dissolve they release material even when exposed to weak solvents like water and salt solutions. Exposures to lung simulant fluids show relatively slow dissolution rates comparable to what is found using only water. Sequential extraction of particles shows that variation between particles is very large; some dissolve easily while some does not. Of radiological importance is the disruption of particles when exposed to dissolution. (author)

  5. Evaluation of glass leaching as nutrient source for microalgae growth

    International Nuclear Information System (INIS)

    Grabska, N.; Tamayo, A.; Mazo, M. A.; Pascual, L.; Rubio, J.

    2015-01-01

    Three glasses with an elemental composition similar to the nutrient ratio required for Spirulina platensis growth and with different SiO 2 content have been prepared. The glasses were crushed and sieved into 2 different fractions and the effect of the particle size has been studied in terms of the leaching kinetics of each element. The chemical analysis of the leaching water was used for obtaining the dissolution rate curves for each element taking part of the glass composition. From the calculation of the leaching rate constant and the exponential constant of the lixiviation reaction, it has been evaluated the Spirulina platensis growth in ambient normal conditions of light, temperature and pH of the growing media. It has been concluded that, either from the modification of the chemical composition of the glass or its particle size, it is possible to tune the delivery of the nutrients to match the growth rate of Spirulina platensis. (Author)

  6. Investigations into Recycling Zinc from Used Metal Oxide Varistors via pH Selective Leaching: Characterization, Leaching, and Residue Analysis

    Science.gov (United States)

    Gutknecht, Toni; Gustafsson, Anna; Forsgren, Christer; Steenari, Britt-Marie

    2015-01-01

    Metal oxide varistors (MOVs) are a type of resistor with significantly nonlinear current-voltage characteristics commonly used in power lines to protect against overvoltages. If a proper recycling plan is developed MOVs can be an excellent source of secondary zinc because they contain over 90 weight percent zinc oxide. The oxides of antimony, bismuth, and to a lesser degree cobalt, manganese, and nickel are also present in varistors. Characterization of the MOV showed that cobalt, nickel, and manganese were not present in the varistor material at concentrations greater than one weight percent. This investigation determined whether a pH selective dissolution (leaching) process can be utilized as a starting point for hydrometallurgical recycling of the zinc in MOVs. This investigation showed it was possible to selectively leach zinc from the MOV without coleaching of bismuth and antimony by selecting a suitable pH, mainly higher than 3 for acids investigated. It was not possible to leach zinc without coleaching of manganese, cobalt, and nickel. It can be concluded from results obtained with the acids used, acetic, hydrochloric, nitric, and sulfuric, that sulfate leaching produced the most desirable results with respect to zinc leaching and it is also used extensively in industrial zinc production. PMID:26421313

  7. Investigations into Recycling Zinc from Used Metal Oxide Varistors via pH Selective Leaching: Characterization, Leaching, and Residue Analysis

    Directory of Open Access Journals (Sweden)

    Toni Gutknecht

    2015-01-01

    Full Text Available Metal oxide varistors (MOVs are a type of resistor with significantly nonlinear current-voltage characteristics commonly used in power lines to protect against overvoltages. If a proper recycling plan is developed MOVs can be an excellent source of secondary zinc because they contain over 90 weight percent zinc oxide. The oxides of antimony, bismuth, and to a lesser degree cobalt, manganese, and nickel are also present in varistors. Characterization of the MOV showed that cobalt, nickel, and manganese were not present in the varistor material at concentrations greater than one weight percent. This investigation determined whether a pH selective dissolution (leaching process can be utilized as a starting point for hydrometallurgical recycling of the zinc in MOVs. This investigation showed it was possible to selectively leach zinc from the MOV without coleaching of bismuth and antimony by selecting a suitable pH, mainly higher than 3 for acids investigated. It was not possible to leach zinc without coleaching of manganese, cobalt, and nickel. It can be concluded from results obtained with the acids used, acetic, hydrochloric, nitric, and sulfuric, that sulfate leaching produced the most desirable results with respect to zinc leaching and it is also used extensively in industrial zinc production.

  8. Method of gradual acid leaching of uranium ores of silicate and aluminosilicate nature

    International Nuclear Information System (INIS)

    Bosina, B.; Krepelka, J.; Urban, P.; Kropacek, J.; Stransky, J.

    1987-01-01

    Leaching uranium ore pulp is divided into two stages. The first stage takes place without any addition of a leaching agent at elevated pressure and temperature. In the second stage, sulfuric acid is added to the pulp (50 to 1000 kg per tonne of ore) or an oxidation agent. Leaching then proceeds according to routine procedures. The procedure is used to advantage for silicate or aluminosilicate ores which contain uranium minerals which are difficult to leach, pyrite and reducing substances. The two stage leaching allows to use the technology of pressure leaching, reduces consumption of sulfuric acid and oxidation agents and still achieves the required reduction oxidation potential. (E.S.)

  9. Leaching of arsenic, copper and chromium from thermally treated soil.

    Science.gov (United States)

    Kumpiene, Jurate; Nordmark, Désirée; Hamberg, Roger; Carabante, Ivan; Simanavičienė, Rūta; Aksamitauskas, Vladislovas Česlovas

    2016-12-01

    Thermal treatment, if properly performed, is an effective way of destroying organic compounds in contaminated soil, while impact on co-present inorganic contaminants varies depending on the element. Leaching of trace elements in thermally treated soil can be altered by co-combusting different types of materials. This study aimed at assessing changes in mobility of As, Cr and Cu in thermally treated soil as affected by addition of industrial by-products prior to soil combustion. Contaminated soil was mixed with either waste of gypsum boards, a steel processing residue (Fe 3 O 4 ), fly ash from wood and coal combustion or a steel abrasive (96.5% Fe 0 ). The mixes and unamended soil were thermally treated at 800 °C and divided into a fine fraction 0.125 mm to simulate particle separation occurring in thermal treatment plants. The impact of the treatment on element behaviour was assessed by a batch leaching test, X-ray absorption spectroscopy and dispersive X-ray spectrometry. The results suggest that thermal treatment is highly unfavourable for As contaminated soils as it increased both the As leaching in the fine particle size fraction and the mass of the fines (up to 92%). Soil amendment with Fe-containing compounds prior to the thermal treatment reduced As leaching to the levels acceptable for hazardous waste landfills, but only in the coarse fraction, which does not justify the usefulness of such treatment. Among the amendments used, gypsum most effectively reduced leaching of Cr and Cu in thermally treated soil and could be recommended for soils that do not contain As. Fly ash was the least effective amendment as it increased leaching of both Cr and As in majority of samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. [Mixture Leaching Remediation Technology of Arsenic Contaminated Soil].

    Science.gov (United States)

    Chen, Xun-feng; Li, Xiao-ming; Chen, Can; Yang, Qi; Deng, Lin-jing; Xie, Wei-qiang; Zhong, Yui; Huang, Bin; Yang, Wei-qiang; Zhang, Zhi-bei

    2016-03-15

    Soil contamination of arsenic pollution has become a severely environmental issue, while soil leaching is an efficient method for remediation of arsenic-contaminated soil. In this study, batch tests were primarily conducted to select optimal mixture leaching combination. Firstly, five conventional reagents were selected and combined with each other. Secondly, the fractions were analyzed before and after the tests. Finally, to explore the feasibility of mixed leaching, three soils with different arsenic pollution levels were used to compare the leaching effect. Comparing with one-step washing, the two-step sequential washing with different reagents increased the arsenic removal efficiency. These results showed that the mixture of 4 h 0.5 mol · L⁻¹ NaOH + 4 h 0.1 mol · L⁻¹ EDTA was found to be practicable, which could enhance the removal rate of arsenic from 66.67% to 91.83%, and the concentration of arsenic in soil was decreased from 186 mg · kg⁻¹ to 15.2 mg · kg⁻¹. Furthermore, the results indicated that the distribution of fractions of arsenic in soil changed apparently after mixture leaching. Leaching process could significantly reduce the available contents of arsenic in soil. Moreover, the mixture of 0.5 mol · L⁻¹ NaOH + 0.1 mol L⁻¹ EDTA could well decrease the arsenic concentration in aluminum-type soils, while the mixture of 0.5 mol · L⁻¹ OX + 0.5 mol · L⁻¹ NaOH could well decrease the arsenic concentration in iron-type soils.

  11. Selective Leaching of Gray Cast Iron: Electrochemical Aspects

    International Nuclear Information System (INIS)

    Na, Kyung Hwan; Yun, Eun Sub; Park, Young Sheop

    2010-01-01

    Currently, to keep step with increases in energy consumption, much attention has been paid to the construction of new nuclear power plants (NPPs) and to the continued operation of NPPs. For continued operation, the selective leaching of materials should be evaluated by visual inspections and hardness measurements as a part of One-Time Inspection Program according to the requirements of the guidelines for continued operation of pressured water reactors (PWRs) in Korea and license renewals in the United States, entitled the 'Generic Aging Lessons Learned (GALL) report.' However, the acceptance criteria for hardness have yet to be provided. Recently, USNRC released a new draft of the GALL report for comment and plans to publish its formal version by the end of 2010. In the new draft, the quantitative acceptance criteria for hardness are given at last: no more than a 20 percent decrease in hardness for gray cast iron and brass containing more than 15 percent zinc. Selective leaching is the preferential removal of one of the alloying elements from a solid alloy by corrosion processes, leaving behind a weakened spongy or porous residual structure. The materials susceptible to selective leaching include gray cast iron and brass, which are mainly used as pump casings and valve bodies in the fire protection systems of NPPs. Since selective leaching proceeds slowly during a long period of time and causes a decrease in strength without changing the overall dimensions of original material, it is difficult to identify. In the present work, the selective leaching of gray cast iron is investigated in terms of its electrochemical aspects as part of an ongoing research project to study the changes in metal properties by selective leaching

  12. Partitioning of elements during coal combustion and leaching experiments

    Energy Technology Data Exchange (ETDEWEB)

    Wang Wen-feng; Qin Yong; Song Dang-yu; Wang Jun-yi [China University of Mining & Technology, Xuzhou (China). School of Resources and Earth Science

    2009-04-15

    The mineral component and content of sulfur and 42 major and trace elements of the feed coal, fly and bottom ashes collected from Shizuishan coal-fired power plant, Ningxia, China were analyzed using AFS, INAA, ICP-MS, ICP-AES, XRD. Based on the coal combustion and leaching experiments, the partitioning of these elements during coal combustion and the leaching behavior of the 11 potentially hazardous elements, including As, Cd, Co, Cr, Hg, Mo, Ni, Pb, Se, Th and U were investigated. The results show that the distribution of elements in the fly and bottom ashes is controlled by their volatilities and modes of occurrence in the coal. The degree of volatilization of elements may be mainly associated with boiling/melting points of these elements and their compounds. The elements easily volatilized, organically bound or associated with sub-micrometer and nano minerals (e.g. Al and Na) tend to be enriched in the fine fractions of fly ash, and most elements do not vaporize which are approximately equally partitioned in the fly and bottom ashes. The emission rates of As, Cr, K, Mg, Mn, Mo, Pb, Sb, and Zn are notably influenced by the temperature ranging from 877 to 1300{sup o}C. The leaching behavior of elements depend significantly on their geochemical properties and modes of occurrence. The elements with a low degree of volatilization are not easily leached, while volatile elements easily leached under the acid conditions. Arsenic, B Br, Cd, Cu, Hg, Pb, S, Sb and Se show a higher emission rate during coal combustion, and the leached concentrations of Cd, Co, Mo, Ni and U in the acid media exceed their limited concentrations recommended in relevant environment quality standards for water, which will harm the environment. 32 refs., 4 figs., 4 tabs.

  13. Definition of a concrete bio-decontamination process in nuclear substructures

    International Nuclear Information System (INIS)

    Jestin, A.

    2005-05-01

    The decontamination of sub-structural materials represents a stake of high-importance because of the high volume generated. It is agreed then to propose efficient and effective processes. The process of bio-decontamination of the hydraulic binders leans on the mechanisms of biodegradation of concretes, phenomenon characterized in the 40's by an indirect attack of the material by acids stem from the microbial metabolism: sulphuric acid (produced by Thiobacillus), nitric acid (produced by Nitrosomonas and Nitrobacter) and organic acids (produced by fungi). The principle of the bio-decontamination process is to apply those micro-organisms on the surface of the contaminated material, in order to damage its surface and to retrieve the radionuclides. One of the multiple approaches of the process is the use of a bio-gel that makes possible the micro-organisms application. (author)

  14. Quantitative Estimates of Bio-Remodeling on Coastal Rock Surfaces

    Directory of Open Access Journals (Sweden)

    Marta Pappalardo

    2016-05-01

    Full Text Available Remodeling of rocky coasts and erosion rates have been widely studied in past years, but not all the involved processes acting over rocks surface have been quantitatively evaluated yet. The first goal of this paper is to revise the different methodologies employed in the quantification of the effect of biotic agents on rocks exposed to coastal morphologic agents, comparing their efficiency. Secondly, we focus on geological methods to assess and quantify bio-remodeling, presenting some case studies in an area of the Mediterranean Sea in which different geological methods, inspired from the revised literature, have been tested in order to provide a quantitative assessment of the effects some biological covers exert over rocky platforms in tidal and supra-tidal environments. In particular, different experimental designs based on Schmidt hammer test results have been applied in order to estimate rock hardness related to different orders of littoral platforms and the bio-erosive/bio-protective role of Chthamalus ssp. and Verrucariaadriatica. All data collected have been analyzed using statistical tests to evaluate the significance of the measures and methodologies. The effectiveness of this approach is analyzed, and its limits are highlighted. In order to overcome the latter, a strategy combining geological and experimental–computational approaches is proposed, potentially capable of revealing novel clues on bio-erosion dynamics. An experimental-computational proposal, to assess the indirect effects of the biofilm coverage of rocky shores, is presented in this paper, focusing on the shear forces exerted during hydration-dehydration cycles. The results of computational modeling can be compared to experimental evidence, from nanoscopic to macroscopic scales.

  15. Improvement on LEACH Agreement of Mine Wireless Sensor Network

    Directory of Open Access Journals (Sweden)

    Yun-xiang Liu

    2017-05-01

    Full Text Available Based on the characteristics of wireless sensor network communication in mine, LEACH protocol clustering is optimized, and the factors of energy and distance are considered fully. The selection of cluster head nodes is optimized, and a routing algorithm based on K-means ++ clustering is proposed. The problem of uneven distribution of cluster head nodes, uneven energy consumption and network stability in LEACH algorithm is improved effectively. Simulation results show that the proposed algorithm can improve the energy consumption of the whole network and improve the energy utilization rate, extending the network life cycle effectively.

  16. Leaching of sodium carbonate cakes by nitric acid

    International Nuclear Information System (INIS)

    Troyanker, L.S.; Nikonov, V.N.

    1977-01-01

    The interaction has been studied of soda cakes of fluorite-rare-earth concentrate with nitric acid. The effect of a number of factors on extraction of REE into a nitric solution has been considered: the final acidity of the pulp, the duration of leaching, and the ratio between solid and liquid phases. The effect of adding aluminium nitrate into the pulp has also been studied. It has been shown that three-stage counterflow leaching of soda cakes with nitric acid increases REE extraction approximately by 10%

  17. Selection of lixiviants for in situ uranium leaching. Information circular

    International Nuclear Information System (INIS)

    Tweeton, D.R.; Peterson, K.A.

    1981-10-01

    This Bureau of Mines publication provides information to assist in selecting a lixiviant (leach solution) for in situ uranium leaching. The cost, advantages, and disadvantages of lixiviants currently used and proposed are presented. Laboratory and field tests are described, and applications of geochemical models are discussed. Environmental, economic, and technical factors should all be considered. Satisfying environmental regulations on restoring groundwater quality is becoming an overriding factor, favoring sodium bicarbonate or dissolved carbon dioxide over ammonium carbonate. The cheapest lixiviant is dissolved carbon dioxide, but it is not effective in all deposits. Technical factors include clay swelling by sodium, acid consumption by calcite, and the low solubility of oxygen in shallow deposits

  18. Influence of soil structure on contaminant leaching from injected slurry.

    Science.gov (United States)

    Amin, M G Mostofa; Pedersen, Christina Østerballe; Forslund, Anita; Veith, Tamie L; Laegdsmand, Mette

    2016-12-15

    Animal manure application to agricultural land provides beneficial organic matter and nutrients but can spread harmful contaminants to the environment. Contamination of fresh produce, surface water and shallow groundwater with the manure-borne pollutants can be a critical concern. Leaching and persistence of nitrogen, microorganisms (bacteriophage, E. coli, and Enterococcus) and a group of steroid hormone (estrogens) were investigated after injection of swine slurry into either intact (structured) or disturbed (homogeneous repacked) soil. The slurry was injected into hexaplicate soil columns at a rate of 50 t ha -1 and followed with four irrigation events: 3.5-h period at 10 mm h -1 after 1, 2, 3, and 4 weeks. The disturbed columns delayed the leaching of a conservative tracer and microorganisms in the first irrigation event compared to the intact columns due to the effect of disturbed macropore flow paths. The slurry constituents that ended up in or near the macropore flow paths of the intact soil were presumably washed out relatively quickly in the first event. For the last three events the intact soil leached fewer microorganisms than the disturbed soil due to the bypassing effect of water through the macropore flow path in the intact soil. Estrogen leached from the intact soil in the first event only, but for the disturbed soil it was detected in the leachates of last two events also. Leaching from the later events was attributed to higher colloid transport from the disturbed soils. In contrast, NO 3 -N leaching from the intact soil was higher for all events except the first event, probably due to a lower nitrification rate in the disturbed soil. A week after the last irrigation event, the redistribution of all slurry constituents except NO 3 -N in most of the sections of the soil column was higher for the disturbed soil. Total recovery of E. coli was significantly higher from the disturbed soil and total leaching of mineral nitrogen was significantly

  19. Leaching of Al2O3 in simulated repository conditions

    International Nuclear Information System (INIS)

    Svensson, B.-M.; Dahl, L.

    1978-06-01

    Al 2 O 3 material has been leached at 90 deg C in: simulated ground water at pH 8.5, embedded in bentonite + silica sand saturated with the same water, and in simulated ground water at pH 6 and pH 10. Leaching periods varied from 30 days to 300 days. We observed slight weight increments in all cases from deposits on samples from the environment. These mask weight losses from Al 2 O 3 that may have occurred. (author)

  20. Solvent extraction of uranium from high acid leach solution

    International Nuclear Information System (INIS)

    Ramadevi, G.; Sreenivas, T.; Navale, A.S.; Padmanabhan, N.P.H.

    2010-01-01

    A significant part of the total uranium reserves all over the world is contributed by refractory uranium minerals. The refractory oxides are highly stable and inert to attack by most of the commonly used acids under normal conditions of acid strength, pressure and temperature. Quantitative dissolution of uranium from such ores containing refractory uranium minerals requires drastic operating conditions during chemical leaching like high acid strength, elevated pressures and temperatures. The leach liquors produced under these conditions normally have high free acidity, which affects the downstream operations like ion exchange and solvent extraction

  1. Leaching and solvent extraction at Mary Kathleen Uranium Ltd

    International Nuclear Information System (INIS)

    Richmond, G.D.

    1978-01-01

    Mary Kathleen Uranium Ltd. recommenced operations in early 1976 following a twelve year period of care and maintenance. Several sections of the plant were modified or completely changed for the second operation. The most important change was the replacement of ion exchange with solvent extraction as the means of purifying and upgrading uranium rich solutions. Most of the problems experienced in the solvent extraction system originate from the leach liquor which has a strong tendency to form stable emulsions. This has been countered by some careful control of leaching conditions and by closer observation of operations in the solvent extraction area. Most problems have now been resolved and plant recoveries are quite satisfactory

  2. Quality prediction of a leached produced in a sanitary landfills

    International Nuclear Information System (INIS)

    Agudelo Garcia, Ruben Alberto; Garcia R, Francisco Fernando; Rivera Mesa, Carolina

    2002-01-01

    This paper presents a mathematical model developed with the purpose of predicting the concentration of pollutants in the leached produced by the biological degradation of the solid wastes disposed in sanitary landfills. The model consists in a kinetic equation of first level, able to describe the degradation of the organic matter being the solid residuals. This model was calibrated using the results obtained from six laboratory scale lysimeters operated under different conditions. The model predicted the concentration of the pollutants in the leached with an accuracy of 94%

  3. Imouraren - uranium leaching tests and specificities with analcites

    International Nuclear Information System (INIS)

    Wattinne-Morice, A.; Belieres, M.

    2010-01-01

    Imouraren is a sedimentary uranium deposit (total > 150 000 tU, average U ~ 0.08 %), located in Niger (~ 100 km from Agadez). Uranium mineralization is trapped in sandstones and is widely oxidized (uranotyle, metatuyamunite), but a part remains reduced (pitchblende, uraninite). The sandstones have a peculiar mineralogical assemblage (analcite partly chloritized) which can affect uranium recovery. Several acid heap leaching tests have been completed to determine the most suitable process parameters. Microscopic studies and XRD analysis performed on fresh ore and on leached residue highlight the complex behavior of uranium and the associated mineralogical families during the tests. (author)

  4. Low leach rate glasses for immobilization of nuclear wastes

    International Nuclear Information System (INIS)

    Chick, L.A.; Buckwalter, C.Q.

    1980-10-01

    Improved defense and commercial waste glass have about one order of magnitude lower leach rates at 90 0 C in static deionized water than reference glasses. This durability difference diminishes as the leaching temperature is raised, but at repository temperature less than 150 0 C, the improved compositions would have considerable advantages over reference glases. At the melting temperatures necessary for most of the high-durability glasses, volatility was found to be higher than that experienced in processing current reference glases. Higher volatilities might be compensated for by specific design of the off-gas system for improved off-gas treatment and volatile materials recovery. 6 figures, 2 tables

  5. Evaluation of long term leaching of borosilicate glasses

    International Nuclear Information System (INIS)

    Lanza, F.; Parnisari, E.

    1978-01-01

    For the evaluation of long term hazard of glass, data on long term glass leaching are needed. Moreover for long term leaching a model of homogeneous dissolution seems reasonable and ask for confirmation. Tests were performed at 30 0 , 80 0 , 100 0 , using an apparatus of the Soxhlet type, to 3.600 hours. Results were obtained as a weight loss and analysed following a relation with time composed by a parabolic and a linear part. Analysis of the surface layer using energy dispersion X ray spectrometry were performed. A critical analysis of the results and of the apparatus is presented

  6. Non-destructive assay of leached hulls in a nuclear fuel reprocessing plant

    International Nuclear Information System (INIS)

    Hofstetter, K.J.; Henderson, B.C.; Gray, J.H.; Huff, G.A.

    1978-01-01

    The hull monitor at the Barnwell Nuclear Fuels Plant (BNFP) will be a remotely controlled, fully automated system designed to quantitatively assay leached hulls for undissolved U and Pu. The hull monitor will assay the hulls from one metric ton of fuel per dissolver basket with the design goal of detecting 0.1% undissolved fuel and yet remain within the framework of the BNFP materials flow of five hull baskets per day. The non-destructive assay will be accomplished using a computer-based gamma-ray pulse height analysis system employing a 5 x 5 inch NaI(Tl) scintillation detector. The intense radiations from the fission product isotopes and the activation product isotopes produced in the reactor prevent direct assay of the undissolved fuel left in the hulls. The measurement will be made indirectly by demonstrating a correlation between the amount of 144 Ce undissolved and the remaining U. The isotope 144 Ce is a direct fission product with high cumulative yield. The daughter isotope 144 Pr has a gamma ray at 2.18 MeV well above other predominant radiations in the spectrum from the major interferences 60 Co, 58 Co, 95 Zr( 95 Nb), 137 Cs and 106 Ru( 106 Rh). Segmented scanning operation of the hull monitor is accomplished by rotation and vertical transversal of the hulls container past the detector station. Proper collimation and absorbers are required to maximize the 144 Ce( 144 Pr) to background ratio. A basket indexer is provided which monitors the scanning rate and ensures repositioning. The leached hull monitor system will be interfaced to a computer-based multichannel analyzer for ease of operation and data handling. A calibration basket has been fabricated to accomodate radioactive sources and inactive Zircaloy hulls

  7. Bio-mineralization and potential biogeochemical processes in bauxite deposits: genetic and ore quality significance

    Science.gov (United States)

    Laskou, Magdalini; Economou-Eliopoulos, Maria

    2013-08-01

    The Parnassos-Ghiona bauxite deposit in Greece of karst type is the 11th largest bauxite producer in the world. The mineralogical, major and trace-element contents and δ18O, δ12C, δ34S isotopic compositions of bauxite ores from this deposit and associated limestone provide valuable evidence for their origin and biogeochemical processes resulting in the beneficiation of low grade bauxite ores. The organic matter as thin coal layers, overlying the bauxite deposits, within limestone itself (negative δ12C isotopic values) and the negative δ34S values in sulfides within bauxite ores point to the existence of the appropriate circumstances for Fe bio-leaching and bio-mineralization. Furthermore, a consortium of microorganisms of varying morphological forms (filament-like and spherical to lenticular at an average size of 2 μm), either as fossils or presently living and producing enzymes, is a powerful factor to catalyze the redox reactions, expedite the rates of metal extraction and provide alternative pathways for metal leaching processes resulting in the beneficiation of bauxite ore.

  8. Cover crops effect on farm benefits and nitrate leaching: linking economic and environmental analysis

    Science.gov (United States)

    Gabriel, José Luis; Vanclooster, Marnik; Garrido, Alberto; Quemada, Miguel

    2013-04-01

    Introducing cover crops interspersed with intensively fertilized crops in rotation has the potential to reduce nitrate leaching. However, despite the evident environmental services provided and the range of agronomic benefits documented in the literature, farmers' adoption of the technique is still limited because growing CC could lead to extra costs for the farm in three different forms: direct, indirect, and opportunity costs. Environmental studies are complex, and evaluating the indicators that are representative of the environmental impact of an agricultural system is a complicated task that is conducted by specialized groups and methodologies. Multidisciplinary studies may help to develop reliable approaches that would contribute to choosing the best agricultural strategies based on linking economic and environmental benefits. This study evaluates barley (Hordeum vulgare L., cv. Vanessa), vetch (Vicia villosa L., cv. Vereda) and rapeseed (Brassica napus L., cv. Licapo) as cover crops between maize, leaving the residue in the ground or selling it for animal feeding, and compares the economic and environmental results with respect to a typical maize-fallow rotation. Nitrate leaching for different weather conditions was calculated using the mechanistic-deterministic WAVE model, using the Richards equation parameterised with a conceptual model for the soil hydraulic properties for describing the water flow in the vadose zone, combined with field observed data. The economic impact was evaluated through stochastic (Monte-Carlo) simulation models of farms' profits using probability distribution functions of maize yield and cover crop biomass developed fitted with data collected from various field trials (during more than 5 years) and probability distribution functions of maize and different cover crop forage prices fitted from statistical sources. Stochastic dominance relationships are obtained to rank the most profitable strategies from a farm financial perspective

  9. Analysis of indirect taxation in Ukraine

    Directory of Open Access Journals (Sweden)

    Khodyakova Olga V.

    2014-01-01

    Full Text Available The goal of the article is analysis of the structure and dynamics of indirect taxes for the previous five years and also the influence of indirect taxation upon formation of income of the State Budget of Ukraine. The article analyses the modern state of indirect taxation in Ukraine. Specific weight of the value added tax, excise tax and customs duty are considered in the structure of tax receipts of the consolidated budget of Ukraine as indirect taxes. The article shows that receipts of the State Budget of Ukraine are mostly provided by indirect taxes. The Ukrainian taxation system is mostly a factor of reduction of the level of economic growth and investment activity in the country and the existing system of administering is not completely capable of excluding the possibility of tax evasion. The prospect of further studies in this direction is improvement of organisation of tax control in Ukraine and differentiation of the value added tax rates depending on the level of consumption of goods and level of income of consumers.

  10. Leaching behavior of heavy metals from municipal solid wastes incineration (MSWI) fly ash used in concrete

    International Nuclear Information System (INIS)

    Shi Huisheng; Kan Lili

    2009-01-01

    The characteristics of municipal solid waste incineration (MSWI) fly ash, surface leaching toxicity and successive leaching concentration of heavy metals from MSWI fly ash-cement hardened pastes were studied. And, the relationships between leaching concentrations of heavy metals and leaching time were also discussed. Experimental results showed that immobilization effect of cement on MSWI fly ash is good. Even if MSWI fly ash-cement hardened pastes were damaged, the leaching toxicity is still in a safety range. In early leaching stage, the surface leaching rate is relatively a little high, up to 10 -5 -10 -4 cm d -1 order of magnitude, in the later time of leaching, its rate rapidly declined, down to 10 -7 . Most of leached heavy metals are produced at early ages. The leaching concentration of heavy metals and leaching time has strong positive relationships. In factual utilizing circumstances, heavy metals' leaching from MSWI fly ash-cement hardened pastes is a very slow and gradually diluting process. The leaching toxicity of heavy metals is far lower than that of the National Standard of China, and minimum harmful matters can be contained and released in the environment. Reusing of MSWI fly ash as partial replacement for cement in concrete mixes is potentially feasible.

  11. Long-term leaching behavior of vitrified high-level wastes

    International Nuclear Information System (INIS)

    Ishiguro, Katsuhiko; Sonobe, Hitoshi; Sasaki, Noriaki; Kashihara, Hidechiyo

    1985-01-01

    A long-term Soxhlet leaching test, long-term static leaching test, solubility evaluation test and actual-scale glass solid leaching test were carried out for simulated vitrified wastes. Under high flow-rate leachate conditions, the leaching of high-solubility substances such as B and Na increases almost linearly with time while that of Fe, Ni and rare earth metals strongly depends on their solubility. The overall leaching rate changes (tends to decrease) with time under static conditions. The elution or diffusion is the rate determining step in the earlier region of the leaching process while the solubilities of major components have greater effects in the latter region. The change of the dominant leaching mechanism is delayed more largely as the surface-area to leachate-volume (SA/V) ratio decreases. Actual-scale glass specimens showed almost the same leaching behaviors as small-scale ones. If cracks exist in glass solid, the leaching in them is slow causing little effects on the overall leaching rate. This may be due to the fact that solubility-dependent leaching is occuring in the cracks. The long-term static leaching observations were not satisfactorily explained by the MCC-3 type solubility test results. It is important to clarify the solubility-dependent leaching behaviors at large SA/V ratios. (Nogami, K.)

  12. Leach testing of SYNROC and glass samples at 85 and 200/degree/C

    International Nuclear Information System (INIS)

    Oversby, V.M.; Ringwood, A.E.

    1981-01-01

    Leach tests were conducted on 0.5 g disc samples of SYNROC and two glass types using distilled water at 85 and 200/degree/C. No leaching was detected for SYNROC at either temperature. Thus, the upper limit on leach rate for SYNROC is <0.005 g/m/sup 2/d. Waste glass PNL 76-68 had leach rates of 1.4 g/m/sup 2/ d at 85/degree/C and 8.9 g/m/sup 2/ d at 200/degree/C, while 73-1 glass frit had a leach rate of 41 g/m/sup 2/ d at 200/degree/C. The leach tests were repeated in the presence of rock powders. Again, no leaching was measurable for SYNROC. PNL 76-68 glass had leach rates between 4 and 23 g/m/sup 2/ d at 200/degree/C and 73-1 frit leached at rates between 29 and 176 g/m/sup 2/ d at 200/degree/C. Tests were also conducted on crushed glass samples (PNL 76-68, 100-200 /mu/m size fraction). Bulk leach rates were calculated based on measurement of Ca, Cs, and U in the leach solutions. The results of the leach tests show that SYNROC is several orders of magnitude more resistant to leaching than glass

  13. Recycling of spent lithium-ion battery cathode materials by ammoniacal leaching.

    Science.gov (United States)

    Ku, Heesuk; Jung, Yeojin; Jo, Minsang; Park, Sanghyuk; Kim, Sookyung; Yang, Donghyo; Rhee, Kangin; An, Eung-Mo; Sohn, Jeongsoo; Kwon, Kyungjung

    2016-08-05

    As the production and consumption of lithium ion batteries (LIBs) increase, the recycling of spent LIBs appears inevitable from an environmental, economic and health viewpoint. The leaching behavior of Ni, Mn, Co, Al and Cu from treated cathode active materials, which are separated from a commercial LIB pack in hybrid electric vehicles, is investigated with ammoniacal leaching agents based on ammonia, ammonium carbonate and ammonium sulfite. Ammonium sulfite as a reductant is necessary to enhance leaching kinetics particularly in the ammoniacal leaching of Ni and Co. Ammonium carbonate can act as a pH buffer so that the pH of leaching solution changes little during leaching. Co and Cu can be fully leached out whereas Mn and Al are hardly leached and Ni shows a moderate leaching efficiency. It is confirmed that the cathode active materials are a composite of LiMn2O4, LiCoxMnyNizO2, Al2O3 and C while the leach residue is composed of LiNixMnyCozO2, LiMn2O4, Al2O3, MnCO3 and Mn oxides. Co recovery via the ammoniacal leaching is believed to gain a competitive edge on convenitonal acid leaching both by reducing the sodium hydroxide expense for increasing the pH of leaching solution and by removing the separation steps of Mn and Al. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Development of a computerized data base for low-level radioactive waste leaching data: Topical report

    International Nuclear Information System (INIS)

    Dougherty, D.R.; Colombo, P.

    1986-09-01

    This report documents the development of a computerized data base (db) of leaching data for solidified low-level radioactive waste (LLW) forms. Brookhaven National Lab performed this work under contract with the US Department of Energy's Low-Level Waste Management Program as part of an effort to develop an accelerated leach test(s) that can be used to predict leachabilities of LLW forms over long time periods, i.e., hundreds of years. The accelerated leach test(s) is (are) to be developed based on knowledge of leaching mechanisms and factors that affect leaching. Although developed specifically for the Accelerated Leach Test(s) Program, this db may be useful to others concerned with the management of low-level waste. The db is being developed to provide efficient data compilation and analysis capabilities. The data compiled in the db, which include data from the Accelerated Leach Test(s) Program and selected data from the literature, have been selected to elucidate leaching mechanisms and factors that affect leaching and are not meant to be a comprehensive compilation of leaching data. This report presents the data compilation aspect of the db. It does not present the programmatic results obtained from analysis of the data regarding leaching mechanisms and factors that affect leaching, which will be presented in reports from the Accelerated Leach Test(s) Program. 6 refs

  15. Rejuvenation of residual oil hydrotreating catalysts by leaching of foulant metals. Modelling of the metal leaching process

    Energy Technology Data Exchange (ETDEWEB)

    Marafi, M.; Kam, E.K.T.; Stanislaus, A.; Absi-Halabi, M. [Petroleum Technology Department, Petroleum, Petrochemicals and Materials Division, Kuwait Institute for Scientific Research, Safat (Kuwait)

    1996-11-19

    Increasing emphasis has been paid in recent years on the development of processes for the rejuvenation of spent residual oil hydroprocessing catalysts, which are deactivated by deposition of metals (e.g. vanadium) and coke. As part of a research program on this subject, we have investigated selective removal of the major metal foulant from the spent catalyst by chemical leaching. In the present paper, we report the development of a model for foulant metals leaching from the spent catalyst. The leaching process is considered to involve two consecutive operations: (1) removal of metal foulants along the main mass transfer channels connected to the narrow pores until the pore structure begins to develop and (2) removal of metal foulants from the pore structure. Both kinetic and mass transfer aspects were considered in the model development, and a good agreement was noticed between experimental and simulated results

  16. BioMagResBank.

    NARCIS (Netherlands)

    Ulrich, E.L.; Akutsu, H.; Doreleijers, J.; Harano, Y.; Ioannidis, Y.E.; Lin, J.; Livny, M.; Mading, S.; Maziuk, D.; Miller, Z.; Nakatani, E.; Schulte, C.F.; Tolmie, D.E.; Wenger, R.K.; Yao, H.; Markley, J.L.

    2008-01-01

    The BioMagResBank (BMRB: www.bmrb.wisc.edu) is a repository for experimental and derived data gathered from nuclear magnetic resonance (NMR) spectroscopic studies of biological molecules. BMRB is a partner in the Worldwide Protein Data Bank (wwPDB). The BMRB archive consists of four main data

  17. (Bio)electrochemical ammonia recovery

    NARCIS (Netherlands)

    Kuntke, P.; Sleutels, T.H.J.A.; Rodríguez Arredondo, M.; Georg, S.; Barbosa, S.G.; Heijne, Ter A.; Hamelers, Hubertus V.M.; Buisman, C.J.N.

    2018-01-01

    In recent years, (bio)electrochemical systems (B)ES have emerged as an energy efficient alternative for the recovery of TAN (total ammonia nitrogen, including ammonia and ammonium) from wastewater. In these systems, TAN is removed or concentrated from the wastewater under the influence of an

  18. Bio-actives and Drug

    Indian Academy of Sciences (India)

    Bio-actives. have an effect on or elicit a response from living tissue. Refer to a substance that can be acted upon by a living organism or by an extract from a living organism. are constituents in foods or dietary supplements, other than those needed to meet basic nutritional needs, that are responsible for changes in health ...

  19. A review of Indirect Matrix Converter Topologies

    Directory of Open Access Journals (Sweden)

    Salem Rahmani

    2015-08-01

    Full Text Available Abstract—Matrix Converter (MC is a modern direct AC/AC electrical power converter without dc-link capacitor. MC is operated in four quadrant, assuring a control of the output voltage, amplitude and frequency. The matrix converter has recently attracted significant attention among researchers and it has become increasing attractive for applications of wind energy conversion, military power supplies, induction motor drives, etc. Recently, different MC topologies have been proposed and developed which have their own advantages and disadvantages. Matrix converter can be classified as direct and indirect structures. The direct one has been elaborated in previous work. In this paper the indirect MCs are reviewed. Different characteristics of the indirect MC topologies are mentioned to show the strengths and weaknesses of such converter topologies.

  20. Indirect taxes on food in Southern Brazil

    Directory of Open Access Journals (Sweden)

    Denize Mirian da Silva

    2013-12-01

    Full Text Available The objective of this paper is to estimate the indirect tax burden on food for ten income classes, based on income and household total expenditure in southern Brazil. Thus it can be seen as indirect taxes on foods affect the monetary income and consumption pattern of households. To reach the objectives proposed, will be used the Pintos-Payeras (2008 model. The database iscomposed by microdata from the Household Budgeting Survey (POF 2008-2009 and the tax regulations of the country and the southern states of Brazil. The results show that indirect taxes on food in Southern Brazil is regressive when based on income and expenditure of household , ie , the poorest people pay proportionately more taxes and have their consumption pattern highest taxed ICMS (Brazilian value added tax is the tax that contributes most to the regressivity.