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Sample records for alkaline coal ash

  1. Toxicity mitigation and solidification of municipal solid waste incinerator fly ash using alkaline activated coal ash.

    Science.gov (United States)

    Diaz-Loya, E Ivan; Allouche, Erez N; Eklund, Sven; Joshi, Anupam R; Kupwade-Patil, Kunal

    2012-08-01

    Municipal solid waste (MSW) incineration is a common and effective practice to reduce the volume of solid waste in urban areas. However, the byproduct of this process is a fly ash (IFA), which contains large quantities of toxic contaminants. The purpose of this research study was to analyze the chemical, physical and mechanical behaviors resulting from the gradual introduction of IFA to an alkaline activated coal fly ash (CFA) matrix, as a mean of stabilizing the incinerator ash for use in industrial construction applications, where human exposure potential is limited. IFA and CFA were analyzed via X-ray fluorescence (XRF), X-ray diffraction (XRD) and Inductive coupled plasma (ICP) to obtain a full chemical analysis of the samples, its crystallographic characteristics and a detailed count of the eight heavy metals contemplated in US Title 40 of the Code of Federal Regulations (40 CFR). The particle size distribution of IFA and CFA was also recorded. EPA's Toxicity Characteristic Leaching Procedure (TCLP) was followed to monitor the leachability of the contaminants before and after the activation. Also images obtained via Scanning Electron Microscopy (SEM), before and after the activation, are presented. Concrete made from IFA, CFA and IFA-CFA mixes was subjected to a full mechanical characterization; tests include compressive strength, flexural strength, elastic modulus, Poisson's ratio and setting time. The leachable heavy metal contents (except for Se) were below the maximum allowable limits and in many cases even below the reporting limit. The leachable Chromium was reduced from 0.153 down to 0.0045 mg/L, Arsenic from 0.256 down to 0.132 mg/L, Selenium from 1.05 down to 0.29 mg/L, Silver from 0.011 down to .001 mg/L, Barium from 2.06 down to 0.314 mg/L and Mercury from 0.007 down to 0.001 mg/L. Although the leachable Cd exhibited an increase from 0.49 up to 0.805 mg/L and Pd from 0.002 up to 0.029 mg/L, these were well below the maximum limits of 1.00 and 5

  2. Arsenic concentration in porewater of an alkaline coal ash disposal site: Roles of siderite precipitation/dissolution and soil cover

    Energy Technology Data Exchange (ETDEWEB)

    Kim, K.; Park, S.M.; Kim, J.; Kim, S.H.; Kim, Y.; Moon, J.T.; Hwang, G.S.; Cha, W.S. [Kunsan National University, Jeonbuk (Republic of Korea). Dept. of Environmental Engineering

    2009-09-15

    The geochemical behavior of As in porewaters of an alkaline coal ash disposal site was investigated using multilevel samplers. The disposal site was in operation from 1983 until 1994 and was covered with 0.3-0.5 m thick soils in 2001 when this study was initiated. Sequential extraction analyses and batch leaching experiments were also performed using the coal ash samples collected from the disposal site. The results suggest the important roles of siderite (FeCO{sub 3}) precipitation/dissolution and soil cover, which have been ignored previously. Arsenic levels in the porewater were very low (average of 10 {mu} g L{sup -1}) when the site was covered with soil due to coprecipitation with siderite. The soil cover enabled the creation of anoxic conditions, which raised the Fe concentration by the reductive dissolution of Fe-(hydr)oxides. Because of the high alkalinity generated from the alkaline coal ash, even a small increase in the Fe concentration (0.66 mg L{sup -1} on average) could cause siderite precipitation. When the soil cover was removed. however, an oxidizing condition was created and triggered the precipitation of dissolved Fe as (hydr)oxides. As a result, the dissolution of previously precipitated As-rich siderite caused higher As concentration in the porewater (average of 345 {mu} g L{sup -1}).

  3. Immobilization of B, F, Cr, and As in alkaline coal fly ash through an aging process with water.

    Science.gov (United States)

    Ogawa, Yasumasa; Sakakibara, Kento; Wang, Li; Suto, Koichi; Inoue, Chihiro

    2014-10-01

    Fourteen different alkaline coal fly ashes (CFAs) were used for the experiment, in which each sample was mixed with water to be 28.6% of water content (wt/wt) and aged for 1-4 weeks at 10-30 °C. This simple treatment is advantageous for decreases in water-soluble B, F, Cr, and As. Compared to non-aged CFAs, their water-soluble fractions remained 0.56-88%, 21-85%, 0.37-93% and 2.6-88%, respectively, after aging for a week at 20 °C, although the amounts of Cr and As released from some CFA samples increased. Considering the significant decrease in elution of sulfate, Ca and Al after aging, the immobilization, namely prevention of toxic element elution, could be related to formation of secondary minerals such as portlandite, gypsum and ettringite. Immobilization of B and Cr tends to proceed preferentially under colder conditions. Aging at higher temperatures enhances the leachability of Cr in some CFA samples. Contrary to the behavior of B and Cr, water-soluble F effectively decreases under warmer conditions.

  4. Environmental risks of farmed and barren alkaline coal ash landfills in Tuzla, Bosnia and Herzegovina

    Energy Technology Data Exchange (ETDEWEB)

    Dellantonio, A.; Fitz, W.J.; Custovic, H.; Repmann, F.; Schneider, B.U.; Grunewald, H.; Gruber, V.; Zgorelec, Z.; Zerem, N.; Carter, C.; Markovic, M.; Puschenreiter, M.; Wenzel, W.W. [University for Natural Resources & Applied Life Science, Vienna (Austria)

    2008-06-15

    The disposal of coal combustion residues (CCR) has led to a significant consumption of land in the West Balkan region. In Tuzla (Bosnia and Herzegovina) we studied previously soil-covered (farmed) and barren CCR landfills including management practises, field ageing of CCR and the transfer of trace elements into crops, wild plants and wastewaters. Soil tillage resulted in mixing of cover soil with CCR. Medicago sativa showed very low Cu:Mo ratios (1.25) which may cause hypocuprosis in ruminants. Total loads of inorganic pollutants in the CCR transport water, but not pH (similar to 12), were below regulatory limits of most EU countries. Arsenic concentrations in CCR transport water were < 2 {mu} g l{sup -1} whereas reductive conditions in an abandoned landfill significantly enhanced concentrations in leachates (44 {mu} g l{sup -1}). The opposite pattern was found for Cr likely due to large initial leaching of CrVI. Public use of landfills, including farming, should be based on a prior risk assessment due to the heterogeneity of CCR.

  5. Adsorption of Crystal Violet Dye from Aqueous Solution onto Zeolites from Coal Fly and Bottom Ashes

    OpenAIRE

    Tharcila Colachite Rodrigues Bertolini; Juliana C. Izidoro; Carina P. Magdalena; Denise A. Fungaro

    2013-01-01

    The adsorption of the cationic dye Crystal Violet (CV) over zeolites from coal fly ash (ZFA) and bottom ash (ZBA) was evaluated. The coal fly ash (CFA) and the coal bottom ash (CBA) used in the synthesis of the zeolites by alkaline hydrothermal treatment were collected in Jorge Lacerda coal-fired power plant located at Capivari de Baixo County, in Santa Catarina State, Brazil. The zeolitic materials were characterized predominantly as hydroxy-sodalite and X. The dye adsorption equilibrium was...

  6. Sorption of aqueous phosphorus onto bituminous and lignitous coal ashes

    Energy Technology Data Exchange (ETDEWEB)

    Yan Jinying; Kirk, Donald W. [Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5 (Canada); Jia, Charles Q. [Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, M5S 3E5 (Canada)], E-mail: cqjia@chem-eng.toronto.edu; Liu Xinan [College of Chemical Engineering, Chongqing University, Chongqing (China)

    2007-09-05

    Aiming at the development of a phosphorus removal technology for waste water, phosphate (PO{sub 4}{sup 3-}) retention behavior of bituminous and lignitous coal ashes was investigated using a batch reactor. Ash samples, including fresh and weathered fly and bottom ashes, were studied for their sorption isotherms and reversibility. Fly ashes had a much higher phosphate retention capacity (4000-30,000 mg P/kg) than bottom ashes (15-600 mg P/kg). Lignitous coal ashes were more capable of retaining phosphate than bituminous coal ashes. The retention process was largely irreversible, and the irreversibility increased with the increase in the retention capacity. Weathering enlarged the retention capacity of the bituminous bottom ash, but substantially lowered that of the fly ash, likely due to the difference in the weather-induced changes between the fly and bottom ashes. Sorption isotherms of fly ashes were found to be adequately represented by the Langmuir model while those of bottom ashes fitted better to the Freundlich model. Concentrations of Ca{sup 2+} and PO{sub 4}{sup 3-} in the aqueous phase were measured at the end of sorption and desorption experiments, and were compared with solubilities of three calcium phosphate minerals. The aqueous solutions were saturated or super-saturated with respect to tricalcium phosphate (Ca{sub 3}(PO{sub 4}){sub 2}) and hydroxyapatite (Ca{sub 5}(PO{sub 4}){sub 3}OH), and slightly under-saturated with respect to amorphous calcium phosphate. It is concluded that precipitation of calcium phosphate is the predominant mechanism for phosphate retention by coal ash under the conditions studied. There is a strong and positive correlation between alkalinity and phosphate sorption capacity. Consequently, acid neutralization capacity (ANC) can be used as an indicator of phosphate sorption capacity of coal ashes.

  7. COAL ASH RESOURCES RESEARCH CONSORTIUM

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-12-01

    The Coal Ash Resources Research Consortium (CARRC, pronounced �cars�) is the core coal combustion by-product (CCB) research group at the Energy & Environmental Research Center (EERC). CARRC focuses on performing fundamental and applied scientific and engineering research emphasizing the environmentally safe, economical use of CCBs. CARRC member organizations, which include utilities and marketers, are key to developing industry-driven research in the area of CCB utilization and ensuring its successful application. CARRC continued the partnership of industry partners, university researchers, and the U.S. Department of Energy (DOE) addressing needs in the CCB industry through technical research and development projects. Technology transfer also continued through distribution and presentation of the results of research activities to appropriate audiences, with emphasis on reaching government agency representatives and end users of CCBs. CARRC partners have evolved technically and have jointly developed an understanding of the layers of social, regulatory, legal, and competition issues that impact the success of CCB utilization as applies to the CCB industry in general and to individual companies. Many CARRC tasks are designed to provide information on CCB performance including environmental performance, engineering performance, favorable economics, and improved life cycle of products and projects. CARRC activities from 1993�1998 included a variety of research tasks, with primary work performed in laboratory tasks developed to answer specific questions or evaluate important fundamental properties of CCBs. The tasks summarized in this report are 1) The Demonstration of CCB Use in Small Construction Projects, 2) Application of CCSEM (computer-controlled scanning electron microscopy) for Coal Combustion By-Product Characterization, 3) Development of a Procedure to Determine Heat of Hydration for Coal Combustion By-Products, 4) Investigation of the Behavior of High

  8. Additives for granulating and removing ash from finely dispersed coal

    Energy Technology Data Exchange (ETDEWEB)

    Ivabutin, K.; Fukuda, T.; Goto, M.; Miva, K.; Murata, T.; Taguti, D.

    1982-07-31

    One to thirty percent of a 0.01 to 10 percent solution of synthetic polymers (SPL) of ethylene and vinylacetate or methacrylate, polybutadiene rubbers, resins based on vinylchloride, low molecular PA and so on in an organic solvent mixed with high boiling point bottoms of coal distillation or that of crude oil and or an inorganic electrolyte (a sulfate or phosphate of an alkaline metal) is added to an aqueous suspension of coal powder in order to utilize the dust particles of the coal and to make low ash granules from them.

  9. Optimizing and Characterizing Geopolymers from Ternary Blend of Philippine Coal Fly Ash, Coal Bottom Ash and Rice Hull Ash

    Directory of Open Access Journals (Sweden)

    Martin Ernesto Kalaw

    2016-07-01

    Full Text Available Geopolymers are inorganic polymers formed from the alkaline activation of amorphous alumino-silicate materials resulting in a three-dimensional polymeric network. As a class of materials, it is seen to have the potential of replacing ordinary Portland cement (OPC, which for more than a hundred years has been the binder of choice for structural and building applications. Geopolymers have emerged as a sustainable option vis-à-vis OPC for three reasons: (1 their technical properties are comparable if not better; (2 they can be produced from industrial wastes; and (3 within reasonable constraints, their production requires less energy and emits significantly less CO2. In the Philippines, the use of coal ash, as the alumina- and silica- rich geopolymer precursor, is being considered as one of the options for sustainable management of coal ash generation from coal-fired power plants. However, most geopolymer mixes (and the prevalent blended OPC use only coal fly ash. The coal bottom ash, having very few applications, remains relegated to dumpsites. Rice hull ash, from biomass-fired plants, is another silica-rich geopolymer precursor material from another significantly produced waste in the country with only minimal utilization. In this study, geopolymer samples were formed from the mixture of coal ash, using both coal fly ash (CFA and coal bottom ash (CBA, and rice hull ash (RHA. The raw materials used for the geopolymerization process were characterized using X-ray fluorescence spectroscopy (XRF for elemental and X-ray diffraction (XRD for mineralogical composition. The raw materials’ thermal stability and loss on ignition (LOI were determined using thermogravimetric analysis (TGA and reactivity via dissolution tests and inductively-coupled plasma mass spectrometry (ICP analysis. The mechanical, thermal and microstructural properties of the geopolymers formed were analyzed using compression tests, Fourier transform infra-red spectroscopy (FTIR

  10. Promoting effect of various biomass ashes on the steam gasification of low-rank coal

    International Nuclear Information System (INIS)

    Highlights: • Biomass ash was utilized to promote gasification of low rank coal. • Promoting effect of biomass ash highly depended on AAEM content in the ash. • Stability of the ash could be improved by maintaining AAEM amount in the ash. • Different biomass ash could have completely different catalytic activity. - Abstract: Application of biomass ash as a catalyst to improve gasification rate is a promising way for the effective utilization of waste ash as well as for the reduction of cost. Investigation on the catalytic activity of biomass ash to the gasification of low rank coal was performed in details in the present study. Ashes from 3 kinds of biomass, i.e. brown seaweed/BS, eel grass/EG, and rice straw/RS, were separately mixed with coal sample and gasified in a fixed bed downdraft reactor using steam as the gasifying agent. BS and EG ashes enhanced the gas production rate greater than RS ash. Higher catalytic activity of BS or EG ash was mainly attributed to the higher content of alkali and alkaline earth metal (AAEM) and lower content of silica in it. Higher content of silica in the RS ash was identified to have inhibiting effect for the steam gasification of coal. Stable catalytic activity was remained when the amount of AAEM in the regenerated ash was maintained as that of the original one

  11. Evaluation of heavy metal leaching from coal ash-versus conventional concrete monoliths and debris.

    Science.gov (United States)

    Gwenzi, Willis; Mupatsi, Nyarai M

    2016-03-01

    Application of coal ash in construction materials is constrained by the potential risk of heavy metal leaching. Limited information is available on the comparative heavy metal leaching from coal ash-versus conventional concrete. The current study compared total and leached heavy metal concentrations in unbound coal ash, cement and sand; and investigated the effect of initial leachant pH on heavy metal leaching from coal-ash versus conventional concrete monoliths and their debris. Total Pb, Mn and Zn in coal ash were lower than or similar to that of other materials, while Cu and Fe showed the opposite trend. Leached concentrations of Zn, Pb, Mn, Cu and Fe in unbound coal ash, its concrete and debris were comparable and in some cases even lower than that for conventional concrete. In all cases, leached concentrations accounted for just concrete was minimal and comparable to that of conventional concrete, a finding in contrast to widely held public perceptions and earlier results reported in other regions such as India. In the current study the coal ash, and its concrete and debris had highly alkaline pH indicative of high acid neutralizing and pH buffering capacity, which account for the stabilization of Zn, Pb, Mn, Cu and Fe. Based on the low risk of Zn, Pb, Mn, Cu and Fe leaching from the coal ash imply that such coal ash can be incorporated in construction materials such as concrete without adverse impacts on public and environmental health from these constituents.

  12. Chemical composition of coal and coke ash

    Energy Technology Data Exchange (ETDEWEB)

    Pluzhnikov, A.I.; Tsymbal, G.L.

    1983-05-01

    Karaganda Metals uses low sulphur coal from Karaganda and Kuzbass coalfields and is seeking ways of improving coke in terms of ash and its effect on blast furnace operations, chiefly coke rate reduction. Ash in coke has a critical effect on iron quality, slag composition and desulphurisation. The index used to demonstrate the change in coke consistency during incineration in the blast furnace is that of pyrolytic change: this closely reflects changes in coal charge composition. Control of coke ash content by suitably selecting the charge can be used to influence slag basicity and iron quality.

  13. Mutagenicity and genotoxicity of coal fly ash water leachate

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, R.; Mukherjee, A. [University of Calcutta, Calcutta (India). Dept. of Botany

    2009-03-15

    Fly ash is a by-product of coal-fired electricity generation plants. The prevalent practice of disposal is as slurry of ash and water to storage or ash ponds located near power stations. This has lain to waste thousands of hectares of land all over the world. Since leaching is often the cause of off-site contamination and pathway of introduction into the human environment, a study on the genotoxic effects of fly ash leachate is essential. Leachate prepared from the fly ash sample was analyzed for metal content, and tested for mutagenicity and genotoxicity. Analyses of metals show predominance of the metals - sodium, silicon, potassium, calcium, magnesium, iron, manganese, zinc, and sulphate. The Ames Salmonella mutagenicity assay, a short-term bacterial reverse mutation assay, was conducted on two-tester strains of Salmonella typhimurium strains TA97a and TA102. For genotoxicity, the alkaline version of comet assay on fly ash leachate was carried in vitro on human blood cells and in vivo on Nicotiana plants. The leachate was directly mutagenic and induced significantconcentration-dependent increases in DNA damage in whole blood cells, lymphocytes, and in Nicotiana plants. The comet parameters show increases in tail DNA percentage (%), tail length (mu m), and olive tail moment (arbitrary units). Our results indicate that leachate from fly ash dumpsites has the genotoxic potential and may lead to adverse effects on vegetation and on the health of exposed human populations.

  14. Gasification of high ash, high ash fusion temperature bituminous coals

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Guohai; Vimalchand, Pannalal; Peng, WanWang

    2015-11-13

    This invention relates to gasification of high ash bituminous coals that have high ash fusion temperatures. The ash content can be in 15 to 45 weight percent range and ash fusion temperatures can be in 1150.degree. C. to 1500.degree. C. range as well as in excess of 1500.degree. C. In a preferred embodiment, such coals are dealt with a two stage gasification process--a relatively low temperature primary gasification step in a circulating fluidized bed transport gasifier followed by a high temperature partial oxidation step of residual char carbon and small quantities of tar. The system to process such coals further includes an internally circulating fluidized bed to effectively cool the high temperature syngas with the aid of an inert media and without the syngas contacting the heat transfer surfaces. A cyclone downstream of the syngas cooler, operating at relatively low temperatures, effectively reduces loading to a dust filtration unit. Nearly dust- and tar-free syngas for chemicals production or power generation and with over 90%, and preferably over about 98%, overall carbon conversion can be achieved with the preferred process, apparatus and methods outlined in this invention.

  15. Ash transformation during co-firing coal and straw

    DEFF Research Database (Denmark)

    Zheng, Yuanjing; Jensen, Peter Arendt; Jensen, Anker Degn;

    2007-01-01

    Co-firing straw with coal in pulverized fuel boilers can cause problems related to fly ash utilization, deposit formation, corrosion and SCR catalyst deactivation due to the high contents of Cl and K in the ash. To investigate the interaction between coal and straw ash and the effect of coal qual...

  16. Rising from the ashes: Coal ash in recycling and construction

    Energy Technology Data Exchange (ETDEWEB)

    Naquin, D.

    1998-02-01

    Beneficial Ash Management (BAM, Clearfield, Pa.) has won an environmental award for its use of ash and other waste to fight acid mine drainage. The company`s workers take various waste materials, mainly fly ash from coal-burning plants, to make a cement-like material or grouting, says Ernest Roselli, BAM president. The grouting covers the soil, which helps prevent water from contacting materials. This, in turn, helps control chemical reactions, reducing or eliminating formation of acid mine drainage. The company is restoring the 1,400-acre Bark Camp coal mine site near Penfield in Clearfield County, Pa. Under a no-cost contract with the state of Pennsylvania, BAM is using boiler slag, causticizing byproducts (lime) and nonreclaimable clarifier sludge from International Paper Co. (Erie, Pa.). The mine reclamation techniques developed and monitored at the site include using man-made wetlands to treat acid mine drainage and testing anhydrous ammonia as a similar treatment agent. BAM researches and tests fly ash mixed with lime-based activators as fill material for land reclamation, and develops and uses artificial soil material from paper mill and tannery biosolids.

  17. The Effects of High Alkaline Fly Ash on Strength Behaviour of a Cohesive Soil

    Directory of Open Access Journals (Sweden)

    A. Binal

    2016-01-01

    Full Text Available Contemporarily, there are 16 coal-burning thermal power plants currently operating in Turkey. This number is expected to rise to 46 in the future. Annually, about 15 million tons of fly ash are removed from the existing thermal power plants in Turkey, but a small proportion of it, 2%, is recyclable. Turkey’s plants are fired by lignite, producing Class C fly ash containing a high percentage of lime. Sulfate and alkali levels are also higher in Class C fly ashes. Therefore, fly ash is, commonly, unsuitable as an additive in cement or concrete in Turkey. In this study, highly alkaline fly ash obtained from the Yeniköy thermal power plants is combined with soil samples in different proportions (5%, 10%, 15%, 20%, and 25% and changes in the geomechanical properties of Ankara clay were investigated. The effect of curing time on the physicomechanical properties of the fly ash mixed soil samples was also analyzed. The soil classification of Ankara clay changed from CH to MH due to fly ash additives. Free swelling index values showed a decrease of 92.6%. Direct shear tests on the cohesion value of Ankara clay have shown increases by multiples of 15.85 and 3.01 in internal friction angle values. The California bearing ratio has seen a more drastic increase in value (68.7 times for 25% fly ash mix.

  18. Illinois basin coal fly ashes. 2. Equilibria relationships and qualitative modeling of ash-water reactions

    Science.gov (United States)

    Roy, W.R.; Griffin, R.A.

    1984-01-01

    Alkaline and acidic Illinois Basin coal fly ash samples were each mixed with deionized water and equilibrated for about 140 days to simulate ash ponding environments. Common to both equilibrated solutions, anhydrite solubility dominated Ca2+ activities, and Al3+ activities were in equilibrium with both matrix mullite and insoluble aluminum hydroxide phases. Aqueous silica activities were controlled by both mullite and matrix silicates. The pH of the extract of the acidic fly ash was 4.1 after 24 h but increased to a pH value of 6.4 as the H2SO4, assumed to be adsorbed to the particle surfaces, was exhausted by the dissolution of matrix iron oxides and aluminosilicates. The activities of aqueous Al3+ and iron, initially at high levels during the early stages of equilibration, decreased to below analytical detection limits as the result of the formation of insoluble Fe and Al hydroxide phases. The pH of the extract of the alkaline fly ash remained above a pH value of 10 during the entire equilibration interval as a result of the hydrolysis of matrix oxides. As with the acidic system, Al3+ activities were controlled by amorphous aluminum hydroxide phases that began to form after about 7 days of equilibration. The proposed mechanisms and their interrelations are discussed in addition to the solubility diagrams used to deduce these relationships. ?? 1984 American Chemical Society.

  19. Pozzolanic Reaction Kinetics of Coal Ashes

    Institute of Scientific and Technical Information of China (English)

    ZHENG Hongwei; WANG Zhijuan; QIAN Jueshi; SONG Yuanming; WANG Zhi

    2009-01-01

    The pozzolanic reactivity was determined by the hydration kinetics of pozzolanic reaction based on the fact that the hydration products of active SiO_2 and Al_2O_3 with lime were soluble in dilute hydrochloric acid.The results show that the pozzolanic reaction of active SiO_2 and Al2O3 of coal ashes follows apparent first-order kinetics.The reaction rate constant of FBC ashes is greater than that of PC ashes,while the activation energy of the former is lower than that of the latter.It is confirmed that the pozzolanic activity of fluidized bed combustion(FBC)ashes is significantly higher than that of PC ashes,and the reaction barrier of the former is lower than that of the latter,because the microstructures of FBC ashes,such as mineralogical composition,morphology and polymerization degree of [SiO_4]and[AlO_6]are more favorable to the pozzolanic activity development than those of PC ashes.

  20. Physical, chemical and mineralogical characterisation of hydraulically disposed fine coal ash from SASOL Synfuels

    Energy Technology Data Exchange (ETDEWEB)

    Jabulani S. Mahlaba; Elsabe P. Kearsley; Richard A. Kruger [University of Pretoria, Pretoria (South Africa). Civil Engineering

    2011-07-15

    Coal serves as the primary energy source in most parts of the world. It is a fact that coal combustion yields enormous quantities of fly ash some of which are either hydraulically placed or dry dumped. The current study attempts to provide a comprehensive characterisation of a disused alkaline fine coal ash dam (FCAD) towards assessing environmental impact, rehabilitation and utilisation potential. Fine coal ash refers to a combination of approximately 83% power station fly ash and 17% gasification and bottom ash fines (particles {lt}250 {mu}m) at SASOL Synfuels. The hydration products found in Weathered Fine Coal Ash (WFCA) using X-ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC) are analcime, calcite, C-S-H gel, ettringite, hydrated gehlenite (Strtlingite), magnetite, periclase, pyrrhotite and sillimanite. High resolution Scanning Electron Microscope (SEM) results provide additional proof that hydration products are present in WFCA. No indication of appreciable leaching was given by X-ray Fluorescence (XRF) results except calcium and silicon. Thus evidence exists that pollutants from saline brines are immobilised in WFCA and an insight of reaction kinetics was obtained. High content of amorphous phase and lack of alteration in some geotechnical properties suggest that WFCA can be reutilised with lime addition to increase alkalinity and activate pozzolanic reactions. 48 refs., 18 figs., 4 tabs.

  1. Norm in coal, fly ash and cement

    International Nuclear Information System (INIS)

    Coal is technologically important materials being used for power generation and its cinder (fly ash) is used in manufacturing of bricks, sheets, cement, land filling etc. 222Rn (radon) and its daughters are the most important radioactive and potentially hazardous elements, which are released in the environment from the naturally occurring radioactive material (NORM) present in coal, fly ash and cement. Thus it is very important to carry out radioactivity measurements in coal, fly ash and cement from the health and hygiene point of view. Samples of coal and fly ash from different thermal power stations in northern India and various fly ash using establishments and commercially available cement samples (O.P.C. and P.P.C.) were collected and analyzed for radon concentration and exhalation rates. For the measurements, alpha sensitive LR-115 type II plastic track detectors were used. The radon concentration varied from 147 Bq/m3 to 443 Bq/m3, the radium concentration varied from 1.5 to 4.5 Bq/kg and radon exhalation rate varied from 11.8 mBq.kg-1.h-1 to 35.7 mBq.kg-1.h-1 for mass exhalation rate and from 104.5 mBq.m-2.h-1 to 314.8 mBq.m-2.h-1 for surface exhalation rate in coal samples. The radon concentration varied from 214 Bq/m3 to 590 Bq/m3, the radium concentration varied from 1.0 to 2.7 Bq/kg and radon exhalation rate varied from 7.8 mBq.kg-1.h-1 to 21.6 mBq.kg-1.h-1 for mass exhalation rate and from 138 mBq m-2h-1 to 380.6 mBq.m-2.h-1 for surface exhalation rate in fly ash samples. The radon concentration varied from 157.62 Bq/m3 to 1810.48 Bq/m3, the radium concentration varied from 0.76 Bq/kg to 8.73 Bq/kg and radon exhalation rate varied from 6.07 mBq.kg-1.hr-1 to 69.81 mBq.kg-1.hr-1 for mass exhalation rate and from 107.10 mBq.m-2.hr-1 to 1230.21 mBq.m-2.hr-1 for surface exhalation rate in different cement samples. The values were found higher in P.P.C. samples than in O.P.C. samples. (authors)

  2. pH-dependent leaching of dump coal ash - retrospective environmental analysis

    Energy Technology Data Exchange (ETDEWEB)

    Popovic, A.; Djordjevic, D. [University of Belgrade, Belgrade (Serbia). Dept. of Chemistry

    2009-07-01

    Trace and major elements in coal ash particles from dump of 'Nikola Tesla A' power plant in Obrenovac near Belgrade (Serbia) can cause pollution, due to leaching by atmospheric and surface waters. In order to assess this leaching potential, dump ash samples were subjected to extraction with solutions of decreasing pH values (8.50, 7.00, 5.50, and 4.00), imitating the reactions of the alkaline ash particles with the possible alkaline, neutral, and acidic (e.g., acid rain) waters. The most recently deposited ash represents the greatest environmental threat, while 'aged' ash, because of permanent leaching on the dump, was shown to have already lost this pollution potential. On the basis of the determined leachability, it was possible to perform an estimation of the acidity of the regional rainfalls in the last decades.

  3. Synthesis of Zeolites by Alkaline Activation of Fly Ash

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In terms of mineral transformation, and chemical composition of acid-soluble component as a function of reaction time, the effect of alkaline solution on zeolite-like fly ash was studied by employing fly ash and NaOH solution as starting materials. When fly ash and 1€? 0mol/L NaOH solution were processed at 100℃ for 24h with 1:10 W/S rat io in a relatively closed system, powder XRD patterns of resulting pro ducts indicated the formation of various zeolites. Zeolite P crystalli zed early at low alkaline concentration, which was replaced then by ze olites X and A. At high concentration, hydroxy sodalite was the only n ew phase. Quartz, in fly ash and NaOH solution system, gradually disso lved, and mullite, however, remained stable. It was concluded that, wi th Al/Si and Na/Si finally reaching equilibrium in molar ratio, compos ition of starting mixtures affects the crystallization of zeolite from fly ash.

  4. Evaluation of Pollutant Leaching Potential of Coal Ashes for Recycling

    Science.gov (United States)

    Park, D.; Woo, N. C.; Kim, H.; Yoon, H.; Chung, D.

    2011-12-01

    By 2009, coal ashes produced from coal-based power plants in Korea have been reused as cement supplement materials; however, the rest is mostly disposed in landfills inside the plant properties. Continuous production of coal ashes and limited landfill sites require more recycles of coal ashes as base materials, specifically in constructions of roads and of huge industrial complex. Previous researches showed that coal ashes could contain various metals such as arsenic(As), chromium(Cr), lead(Pb), nickel(Ni), selenium(Se), etc. In this study, we collected four types of bottom ashes and two of fly ashes from four coal-based power plants. These ash samples were tested with distilled water through the column leaching process in oxidized conditions. The column test results were compared with those of total digestion, sequential extraction processes and TCLP. Concentrations of metals in outflows from columns are generally greater in fly ashes than in bottom ashes, specifically for As, Se, B, Sr and SO4. Only one fly ash (J2-F) shows high concentrations of arsenic and selenium in leachate. Sequential extraction results indicate that these metals are in readily soluble forms, such as adsorbed, carbonated, and reducible forms. Results of TCLP analysis indicate no potential contaminants leached from the ashes. In conclusion, recycling of coal combustion ashes could be encouraged with proper tests such as sequential and leaching experiments.

  5. Coal Ash Corrosion Resistant Materials Testing

    Energy Technology Data Exchange (ETDEWEB)

    D. K. McDonald; P. L. Daniel; D. J. DeVault

    2003-08-31

    In April 1999, three identical superheater test sections were installed into the Niles Unit No.1 for the purpose of testing and ranking the coal ash corrosion resistance of candidate superheater alloys. The Niles boiler burns high sulfur coal (3% to 3.5%) that has a reasonably high alkali content, thus the constituents necessary for coal ash corrosion are present in the ash. The test sections were controlled to operate with an average surface metal temperature from approximately 1060 F to 1210 F which was well within the temperature range over which coal ash corrosion occurs. Thus, this combination of aggressive environment and high temperature was appropriate for testing the performance of candidate corrosion-resistant tube materials. Analyses of the deposit and scale confirmed that the aggressive alkali-iron-trisulfate constituent was present at the metal surface and active in tube metal wastage. The test sections were constructed so that the response of twelve different candidate tube and/or coating materials could be studied. The plan was to remove and evaluate one of the three test sections at time intervals of 1 year, 3 years, and 5 years. This would permit an assessment of performance of the candidate materials as a function of time. This report provides the results of the evaluation of Test Section C, including the samples that remained in the Test Section for the full exposure period as well as those that were removed early. The analysis of Test Section C followed much the same protocol that was employed in the assessment of Test Section A. Again, the focus was on determining and documenting the relative corrosion rates of the candidate materials. The detailed results of the investigation are included in this report as a series of twelve appendices. Each appendix is devoted to the performance of one of the candidate alloys. The table below summarizes metal loss rate for the worst case sample of each of the candidate materials for both Test Sections A and C

  6. Recovering germanium from coal ash by chlorination with ammonium chloride

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A new process of enriching germanium from coal ash was developed. The process involves in mixing the coal ash and ammonium chloride and then roasting the mixture to produce germanium chloride that is then absorbed by dilute hydrochloric acid and hydrolyzed to germanium oxide. The germanium recovery reached to 80.2% at the optimum condition: mass ratio of NH4Cl/coal ash is 0.15, roasting temperature 400℃ and roasting time 90 min.

  7. Chemical composition of ash in coal and coke

    Energy Technology Data Exchange (ETDEWEB)

    Pluzhnikov, A.I.; Tsymbal, G.L.

    1983-05-01

    Ash content in coke influences coke consumption rate by blast furnaces. In the Karaganda steelworks a 1% ash content decrease in coke reduces coke consumption by a blast furnace by 1 to 1.6%. Ash content in coke depends on ash content in a coal mixture and ash content in a coal mixture depends on ash content and washability of coal components. Not all ash components are of identical importance for blast furnace coke production. Investigations show that silica and aluminium oxides are only slightly influenced by thermal degradation and reduction reactions which take place during coking. Coal pyrolysis decisively influences content of sodium oxides, potassium oxides or iron oxides. Sodium and potassium carbonates are also unstable and undergo degradation. Taking into consideration that silica and aluminium oxides are not influenced by thermal degradation during coking an increase in the two oxides in a coal mixture used for coking causes an ash content increase in coke. Examples of coal from the Kuzbass and the Vorkuta mines are given. Replacing 5% of the KZh and K coal from Karaganda with G6 coal from the Kuzbass characterized by the identical ash content but by higher content of silica and aluminium oxides causes an increase in ash content in coke ranging from 1.6 to 1.8%. (8 refs.)

  8. Multinuclear NMR approach to coal fly ash characterization

    Energy Technology Data Exchange (ETDEWEB)

    Netzel, D.A.

    1991-09-01

    This report describes the application of various nuclear magnetic resonance (NMR) techniques to study the hydration kinetics and mechanisms, the structural properties, and the adsorption characteristics of coal fly ash. Coal fly ash samples were obtained from the Dave Johnston and Laramie River electric power generating plants in Wyoming. Hydrogen NMR relaxation times were measured as a function of time to observe the kinetics of hydration for the two coal fly ashes at different temperatures and water-to-cement ration. The kinetic data for the hydrated coal fly ashes were compared to the hydration of portland cement. The mechanism used to describe the kinetic data for the hydration of portland cement was applied, with reservation, to describe the hydration of the coal fly ashes. The results showed that the coal fly ashes differ kinetically from that of portland cement and from each other. Consequently, both coal fly ashes were judged to be poorer cementitious materials than portland cement. Carbon-13 NMR CP/MAS spectra were obtained for the anhydrous coal fly ashes in an effort to determine the type of organic species that may be present, either adsorbed on the surface or entrained.

  9. Geoenvironmental aspects of coal refuse-fly ash blends

    OpenAIRE

    Albuquerque, Allwyn J.

    1994-01-01

    The separate land disposal of coal refuse and fly ash presents difficulties throughout the Appalachian region, both in terms of disposal costs per acre and in terms of its potential environmental impacts on soil, ground water, revegetation, and slope stability. The purpose of this study was to determine how fly ash addition to coal refuse would impact on certain geotechnical properties of the refuse disposal piles, and whether the refuse-fly ash blends would be suitable as co-d...

  10. Correlation between the critical viscosity and ash fusion temperatures of coal gasifier ashes

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Peter Y. [National Energy Technology Lab. (NETL), Albany, OR (United States); Kwong, Kyei-Sing [National Energy Technology Lab. (NETL), Albany, OR (United States); Bennett, James [National Energy Technology Lab. (NETL), Albany, OR (United States)

    2015-09-27

    Coal gasification yields synthesis gas, an important intermediate in chemical manufacturing. It is also vital to the production of liquid fuels through the Fischer-Tropsch process and electricity in Integrated Gasification Combined Cycle power generation. Minerals naturally present in coal become molten in entrained-flow slagging gasifiers. Molten coal ash slag penetrates and dissolves refractory bricks, leading to costly plant shutdowns. The extent of coal ash slag penetration and refractory brick dissolution depends on the slag viscosity, the gasification temperature, and the composition of slag and bricks. Here, we measured the viscosity of several synthetic coal ash slags with a high-temperature rotary viscometer and their ash fusion temperatures through optical image analysis. We made all measurements in a carbon monoxide-carbon dioxide reducing atmosphere that approximates coal gasification conditions. Empirical correlation models based on ash fusion temperatures were used to calculate critical viscosity temperatures based on the coal ash compositions. These values were then compared with those obtained from thermodynamic phase-transition models. Finally, an understanding of slag viscosity as a function of ash composition is important to reducing refractory wear in slagging coal gasifiers, which would help to reduce the cost and environmental impact of coal for chemical and electricity production.

  11. Correlation between the critical viscosity and ash fusion temperatures of coal gasifier ashes*

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Peter

    2015-07-02

    Coal gasification yields synthesis gas, an important intermediate in chemical manufacturing. It is also vital to the production of liquid fuels through the Fischer-Tropsch process and electricity in Integrated Gasification Combined Cycle power generation. Minerals naturally present in coal become molten in entrained-flow slagging gasifiers. Molten coal ash slag penetrates and dissolves refractory bricks, leading to costly plant shutdowns. The extent of coal ash slag penetration and refractory brick dissolution depends on the slag viscosity, the gasification temperature, and the composition of slag and bricks. We measured the viscosity of several synthetic coal ash slags with a high-temperature rotary viscometer and their ash fusion temperatures through optical image analysis. All measurements were made in a carbon monoxide-carbon dioxide reducing atmosphere that approximates coal gasification conditions. Empirical correlation models based on ash fusion temperatures were used to calculate critical viscosity temperatures based on the coal ash compositions. These values were then compared with those obtained from thermodynamic phase-transition models. An understanding of slag viscosity as a function of ash composition is important to reducing refractory wear in slagging coal gasifiers, which would help to reduce the cost and environmental impact of coal for chemical and electricity production.

  12. Mössbauer characterization of feed coal, ash and fly ash from a thermal power plant

    International Nuclear Information System (INIS)

    The aim of this work was apply 57Fe Transmission Mössbauer Spectroscopy at room temperature in order to study the occurrence of iron-containing mineral phases in: 1) feed coal; 2) coal ash, obtained in different stages of the ASTM D3174 standard method; and 3) fly ash, produced when coal is burned in the TERMOPAIPA IV thermal power plant localized in Boyacá, Colombia. According to obtained results, we can conclude the occurrence of pyrite and jarosite in the feed coal; Fe2+ and Fe3+ crystalline paramagnetic phases, superparamagnetic hematite and hematite in coal ash; Fe2+ and Fe3+ noncrystalline and crystalline phases, magnetite and hematite in fly ash. Precisely, for a basic understanding, this work discusses some the possible transformations that take place during coal combustion

  13. Supplying Fe from molten coal ash to revive kelp community

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, K.; Yamamoto, M.; Sadakata, M. [University of Tokyo, Tokyo (Japan)

    2006-02-15

    The phenomenon of a kelp-dominated community changing to a crust-dominated community, which is called 'barren-ground', is progressing in the world, and causing serious social problems in coastal areas. Among several suggested causes of 'barren-ground', we focused on the lack of Fe in seawater. Kelp needs more than 200 nM of Fe to keep its community. However there are the areas where the concentration of Fe is less than 1 nM, and the lack of Fe leads to the 'barren-ground.' Coal ash is one of the appropriate materials to compensate the lack of Fe for the kelp growth, because the coal ash is a waste from the coal combustion process and contains more than 5 wt% of Fe. The rate of Fe elution from coal fly ash to water can be increased by 20 times after melting in Ar atmosphere, because 39 wt% of the Fe(III) of coal fly ash was reduced to Fe(II). Additionally molten ash from the IGCC (integrated coal gasification combined cycle) furnace in a reducing atmosphere and one from a melting furnace pilot plant in an oxidizing atmosphere were examined. Each molten ash was classified into two groups; cooled rapidly with water and cooled slowly without water. The flux of Fe elution from rapidly cooled IGCC molten ash was the highest; 9.4 x 10{sup -6} g m{sup -2} d{sup -1}. It was noted that the coal ash melted in a reducing atmosphere could elute Fe effectively, and the dissolution of the molten ash itself controlled the rate of Fe elution in the case of rapidly cooled molten ash.

  14. Multitechnique multielemental analysis of coal and fly ash

    International Nuclear Information System (INIS)

    The coal sample is first ashed with high temperature ashing or with RF plasma low temperature ashing. The coal ash or fly ash can be analyzed for major ash elements by fusing with lithium tetraborate in an automatic fusion device, the Claisse Fluxer. The ash samples are also dissolved in a Parr bomb in a mixture of aqua regia and HF. Subsequently, the solutions are analyzed for eight major (Al, Ca, Fe, K, Mg, Na, Si, and Ti) and 20 trace elements (As, B, Ba, Be, Cd, Co, Cr, Cu, Li, Mn, Mo, Ni, P, Pb, Sb, Se, Sr, U, V, and Zn) by inductively coupled plasma emission spectroscopy. Mercury in coal and fly ash is determined on a separate aliquot by the cold vapor atomic absorption technique. Fluorine and chlorine in the samples are determined by fusing with Na2CO3 and Eschka mixture, respectively, and then measuring the two ions in solution with specific ion electrodes. Oxygen in the samples can be determined rapidly and nondestructively by 14-MeV neutron activation analysis. These methods have been tested by analyzing several NBS coal and fly ash standards with good accuracy and reproducibility. 10 tables

  15. Application of zeolitised coal fly ashes to the depuration of liquid wastes

    Energy Technology Data Exchange (ETDEWEB)

    Emilia Otal; Luis F. Vilches; Natalia Moreno; Xavier Querol; Jose Valea; Constantino Fernandez-Pereira [Universidad de Sevilla, Seville (Spain). Dpto. Ingenieria Quimica y Ambiental, E.S. Ingenieros Industriales

    2005-08-01

    In this study, the application of some zeolitised fly ashes and synthetic zeolites to the decontamination of the leachate produced in a municipal solid waste (MSW) treatment plant and to the liquid waste from a pig farm was analyzed. Thus, the reduction of organic matter (BOD and COD), ammonium and total nitrogen, phosphorus and metals contents after a zeolite treatment was evaluated. Several synthetic zeolites were tested: some commercial zeolites and other synthetic zeolites and zeolitised ashes obtained after a coal fly ash alkaline hydrothermal process. Two forms of contact between the zeolitic material and the liquid waste were tested: in a stirred tank and in a column. In addition, other variables determined were the amount of zeolite and the residence time. The results showed that zeolites, especially zeolitised fly ash, clearly produced a strong reduction in the leachate nitrogen and phosphorus content. 14 refs., 1 fig., 9 tabs.

  16. Coal Ash Corrosion Resistant Materials Testing

    Energy Technology Data Exchange (ETDEWEB)

    D. K. McDonald; P. L. Daniel; D. J. DeVault

    2007-12-31

    In April 1999, three identical superheater test sections were installed into the Niles Unit No.1 for the purpose of testing and ranking the coal ash corrosion resistance of candidate superheater alloys. The Niles boiler burns high sulfur coal (3% to 3.5%) that has a moderate alkali content (0.2% sodium equivalents), thus the constituents necessary for coal ash corrosion are present in the ash. The test sections were controlled to operate with an average surface metal temperature from approximately 1060 F to 1210 F which was within the temperature range over which coal ash corrosion occurs. Thus, this combination of aggressive environment and high temperature was appropriate for testing the performance of candidate corrosion-resistant tube materials. Analyses of the deposit and scale confirmed that aggressive alkali sulfate constituents were present at the metal surface and active in tube metal wastage. The test sections were constructed so that the response of twelve different candidate tube and/or coating materials could be studied. The plan was to remove and evaluate one of the three test sections at time intervals of 1 year, 3 years, and 5 years. This would permit an assessment of performance of the candidate materials as a function of time. Test Section A was removed in November 2001 after about 24 months of service at the desired steam temperature set point, with about 15.5 months of exposure at full temperature. A progress report, issued in October 2002, was written to document the performance of the candidate alloys in that test section. The evaluation described the condition of each tube sample after exposure. It involved a determination of the rate of wall thickness loss for these samples. In cases where there was more than one sample of a candidate material in the test section, an assessment was made of the performance of the alloy as a function of temperature. Test Sections B and C were examined during the November 2001 outage, and it was decided that

  17. Gamma isotopic analysis of the coals and ashes from coal fired power plants of Turkey

    International Nuclear Information System (INIS)

    Gamma-isotopic analysis of the ashes produced by the combustion of lignite in power stations of Turkey together with the parent coal samples was performed with the aim to estimate its potential adverse impacts on human health. Gamma-isotopic analysis indicated that all samples contained 226Ra (coal samples: 89-148 Bq kg-1; ash samples: 15-26 Bq kg-1), 238U (coal samples: 2-4 μg g-1; ash samples: 9-33 μg g-1), 232Th (coal samples: 1-9 μg g-1; ash samples: 8-12μg g-1), and 40K (coal samples: 26-67 Bq kg-1; ash samples: not detected). 134Cs and 137Cs have not been found in the samples. (author)

  18. Ash formation under pressurized pulverized coal combustion conditions

    Science.gov (United States)

    Davila Latorre, Aura Cecilia

    Coal combustion is a source of inorganic particulate matter (ash), which can deposit in boilers and also be emitted into the atmosphere becoming part of ambient fine particulate matter (PM 2.5). In order to decrease coal combustion emissions per unit of power produced, higher efficiency systems have been proposed, including systems operating at elevated pressures. These new operating conditions will affect pollutant formation mechanisms, particularly those associated with the conversion of mineral matter to ash. Ash particle formation mechanisms are particularly sensitive to changes in pressure as they are related to the structure of coal char particles at early stages of combustion. To assess the importance of pressure on ash particle formation, pyrolyzed chars and ash particles from pressurized pulverized combustion of two bituminous and one subbituminous U.S. coals at operating pressures up to 30 atm were studied. Pressure changes the distribution of char particle types, changing the spatial distribution of the minerals during the combustion process and therefore affecting particle formation mechanisms. Chars were examined by Scanning Electron Microscopy (SEM) and classified into two different types (cenospheric and solid) depending on porosity and wall thickness. A correlation for estimating the amount of these cenospheric char particles was then proposed for bituminous coals based on the operating conditions and coal maceral analysis. The ash particle size distribution of the coals combusted at different operating pressures was measured using Computer Controlled Scanning Electron Microscopy (CCSEM). The results of the char characterization and ash particle size distribution measurements were then incorporated into an ash particle formation algorithm that was proposed and implemented. The model predicts ash particle size and composition distributions at elevated pressures under conditions of complete char burnout. Ash predictions were calculated by first

  19. Effect of ash components on the ignition and burnout of high ash coals

    Energy Technology Data Exchange (ETDEWEB)

    Feng, B.; Yan, R.; Zheng, C.G. [Huazhong University of Science and Technology, Wuhan (China). National Laboratory of Coal Combustion

    1998-11-01

    The effect of the ash components on the ignition and burnout of four Chinese high ash coals were studied by thermogravimetric analysis. To investigate the influence of the ash components, comparative experiments were carried out with original, deashed and impregnated coals. Eleven types of ash components, such as SiO{sub 2}, CaCO{sub 3}, MgO, Na{sub 2}CO{sub 3}, K{sub 2}CO{sub 3}, Al{sub 2}O{sub 3}, TiO{sub 2}, Fe{sub 2}O{sub 3}, FeS{sub 2}, NH{sub 4}Fe(SO{sub 4}){sub 2}{center_dot}12H{sub 2}O and FeSO{sub 4},(NH{sub 4}){center_dot}6H{sub 2}O were used in the present study. It was found that most of the ash components have negative effects. The strong influence of some ash components suggests that the combustion characteristics of high ash coal may be determined by the ash composition. 5 refs., 2 figs., 2 tabs.

  20. Mechanism of bioleaching of coal fly ash by Thiobacillus thiooxidans

    Energy Technology Data Exchange (ETDEWEB)

    Seidel, A.; Zimmels, Y.; Armon, R. [Technion Israel Institute of Technology, Haifa (Israel). Faculty of Civil Engineering

    2001-06-15

    Bioleaching of aluminum and iron from coal fly ash (CFA) by Thiobacillus thiooxidans (T thiooxidans) bacteria is considered. The interactions between bacteria, metabolic products, CFA particles, and leaching products were studied. It is demonstrated that bacterial growth and the amount of metals leached from the CFA are coupled through biological and chemical interactions, which involve the various components in this system. Bioleaching experiments were performed batch wise by suspending up to 10% (w/v) CFA in T thiooxidans growth medium containing cell inoculum for a typical 3 week period of time. The results show that under the same conditions, similar leaching levels are obtained by sulfuric acid and bioleaching of CFA, and the contribution of other metabolites is insignificant. CFA inhibits the growth rate through two major effects. The first is due to the alkaline components released by the CFA that cause a rise in the pH, and a corresponding delay in growth. The second is attributed to the random attachment of the bacteria to both the sulfur particles (the energy source) and the barren CFA particles, resulting in a so-called 'dilution effect' of the sulfur particles, and an inhibition of the initial growth rate. However, after an adaptation period of the bacteria the subsequent growth rate, the maximal cell concentration and minimal pH were similar to those obtained in the control experiment, irrespective of CFA content.

  1. Coal fly ash: a retrospective and future look

    Energy Technology Data Exchange (ETDEWEB)

    Manz, O.E. [University of North Dakota, Grand Forks, ND (United States). Civil Engineering Dept.

    1998-07-01

    In 1996, approximately 7.28 million metric tons (8.02 million short tons) of coal fly ash was used in the United States in cement and concrete products. The amount of fly ash in typical structural concrete applications ranges from 15 to 35% by weight, with amounts up to 70% for mass concrete in dams, walls, and girders and for roller-compacted concrete pavements and parking areas. Various concrete mixtures are produced with coal fly ash, including regular weight and lightweight concretes, high-strength concrete, low-slump paving concrete, and architectural concrete. With the principal exception of high-strength concrete, these mixtures are routinely air-entrained for added workability and for resistance to freezing and thawing. A state-of-the-art report on the use of coal fly ash in concrete has been prepared by the American Concrete Institute (ACI): Use of Fly Ash in Concrete, ACI 232.2R-96. Fly ash for use as a mineral admixture in concrete is covered in a specification published by the American Society for Testing and Materials (ASTM): Mineral Admixture in Portland Cement Concrete, ASTM C618. Revisions to the Canadian Standard CSA A 23.5 are also discussed, together with barriers to the use of fly ash. 2 photos.

  2. COAL-FIRED UTILITY BOILERS: SOLVING ASH DEPOSITION PROBLEMS; TOPICAL

    International Nuclear Information System (INIS)

    The accumulation of slagging and fouling ash deposits in utility boilers has been a source of aggravation for coal-fired boiler operators for over a century. Many new developments in analytical, modeling, and combustion testing methods in the past 20 years have made it possible to identify root causes of ash deposition. A concise and comprehensive guidelines document has been assembled for solving ash deposition as related to coal-fired utility boilers. While this report accurately captures the current state of knowledge in ash deposition, note that substantial research and development is under way to more completely understand and mitigate slagging and fouling. Thus, while comprehensive, this document carries the title ''interim,'' with the idea that future work will provide additional insight. Primary target audiences include utility operators and engineers who face plant inefficiencies and significant operational and maintenance costs that are associated with ash deposition problems. Pulverized and cyclone-fired coal boilers are addressed specifically, although many of the diagnostics and solutions apply to other boiler types. Logic diagrams, ash deposit types, and boiler symptoms of ash deposition are used to aid the user in identifying an ash deposition problem, diagnosing and verifying root causes, determining remedial measures to alleviate or eliminate the problem, and then monitoring the situation to verify that the problem has been solved. In addition to a step-by-step method for identifying and remediating ash deposition problems, this guideline document (Appendix A) provides descriptions of analytical techniques for diagnostic testing and gives extensive fundamental and practical literature references and addresses of organizations that can provide help in alleviating ash deposition problems

  3. Characteristic of elements in coal bottom ash and fly ash by instrumental neutron activation analysis (INAA)

    International Nuclear Information System (INIS)

    Coal-fired power plant and industrial stacks that using coal produce solid waste such as bottom ash and fly ash. Determination of elements in these wastes qualitatively and quantitatively is usually the first step taken for subsequent evaluation of the associated environmental and biological risks. In this study, the determination of trace elements in bottom ash and fly ash by instrumental neutron activation analysis was carried out. The samples were irradiated at rabbit facility in G.A. Siwabessy reactor with neutron flux ~ 1013 n.cm-2.s-1, and then counted by HPGe spectrometer gamma detector. The validation of method was performed by characterization of standard reference material (SRM) 1633b coal fly ash from National Institute of Standards and Technology (NIST). Some elements such as Al, As, Ce, Co, Cr, Cs, Fe, K, La, Mn, Na, Sc, Sm, Ti and V were detected in both samples. The concentration of environmentally toxic elements, As and Cr in bottom ash were 6.24 and 137.4 mg/kg, whereas in fly ash were 6.37 and 39.0 mg/kg respectively. Arsenic concentrations had been over the standard value based on PP no.85/1999. (author)

  4. Bactericidal and virucidal mechanisms in the alkaline disinfection of compost using calcium lime and ash.

    Science.gov (United States)

    Hijikata, Nowaki; Tezuka, Rui; Kazama, Shinobu; Otaki, Masahiro; Ushijima, Ken; Ito, Ryusei; Okabe, Satoshi; Sano, Daisuke; Funamizu, Naoyuki

    2016-10-01

    In the present study, the bactericidal and virucidal mechanisms in the alkaline disinfection of compost with calcium lime and ash were investigated. Two indicator microorganisms, Escherichia coli and MS2 coliphage, were used as surrogates for enteric pathogens. The alkaline-treated compost with calcium oxide (CaO) or ash resulted primarily in damage to the outer membrane and enzyme activities of E. coli. The alkaline treatment of compost also led to the infectivity loss of the coliphage because of the partial capsid damage and RNA exteriorization due to a raised pH, which is proportional to the amount of alkaline agents added. These results indicate that the alkaline treatment of compost using calcium oxide and ash is effective and can contribute to the safe usage of compost from a mixing type dry toilet. PMID:27562698

  5. Activation of fly ashes by the high temperature and high alkalinity in ASR tests

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    High temperature and high alkalinity are typical testing conditions to accelerate the appraisal process of the suppressing effect of fly ashes on alkali silica reaction(ASR),but the reaction mechanism of fly ashes would be quite different under such conditions compared to the normal condition of temperature and alkalinity.To make a reasonable analysis of the suppressing effect of fly ashes,13 types of fly ashes were tested in this paper by both the accelerated mortar bar test method and the 60°C accelerated concrete prism test method.The results showed that the effect of fly ashes would be magnified under the condition of high temperature and high alkalinity.The XRD analysis showed that all the phases of fly ash could react with the hot alkaline solution except for mullite and a small amount of quartz.Fly ash could be significantly activated by the 80°C 1 mol/L NaOH solution,and form mainly C-S-H phase and P type zeolite,but its effect on inhibiting ASR was exaggerated then.According to the mortar strength test and the ASR suppressing test results,C-S-H phase contributed to mortar strength,but its amount did not decide the ASR suppressing effect of fly ash.

  6. Is coal ash and slag any useful or unloaded wastes?

    International Nuclear Information System (INIS)

    It is well known that all types of coal, like most materials found in nature, contain trace quantities of the naturally occurring primordial radionuclides (uranium and thorium families and potassium-40). Therefore, the combustion of coal results in partitioning of radionuclides included in the non-combustible mineral matter, between the bottom ash and fly ash, and in the release into the environment of large amounts of coal ash. Emissions from thermal power stations in gaseous and particulate form contain radioisotopes arising from the uranium and thorium series as well as from 40K. They are discharged into the environment causing changes in the natural radiation background and radiation exposures to the population. The continued releases of these materials to environment may result in a buildup in the air, water and soil of the radionuclides, particularly radium-226. There will be an increase of the basic radiation rate in the neighborhood area of these plants and consequently relatively higher exposure of the local population to radiation. Coal burning is, therefore, one of the sources of technologically enhanced exposure to humans from natural radionuclides (1,2,3,4,5,6). Coal based thermal power plants constitute about 35% of quantum of energy supply in Romania. In view of the importance of coal for energy supply in Romania, we were interested in knowing possible uses of the resulting wastes and minimize the following harmful consequences of coal burning

  7. The Mineral Transformation of Huainan Coal Ashes in Reducing Atmospheres

    Institute of Scientific and Technical Information of China (English)

    LI Han-xu; Yoshihiko Ninomiya; DONG Zhong-bing; ZHANG Ming-xu

    2006-01-01

    By using the advanced instrumentation of a Computer Controlled Scanning Electron Microscope (CCSEM),X-ray diffraction (XRD) and X-ray fluorescence (XRF), the ash composition and the mineral components of six typical Huainan coals of different origins were studied. The transformation of mineral matter at high temperatures was tracked by XRD in reducing conditions. The quartz phase decreased sharply and the anorthite content tended to increase at first and then decreased with increasing temperatures. The formed mullite phase reached a maximum at 1250 ℃ but showed a tendency of slow decline when the temperature was over 1250 ℃. The mullite formed in the heating process was the main reason of the high ash melting temperature of Huainan coals. Differences in peak intensity of mullite and anorthite reflected differences in phase concentration of the quenched slag fractions, which contributed to the differences in ash melting temperatures. The differences in the location of an amorphous hump maximum indicated differences of glass types which may affect ash melting temperatures. For Huainan coal samples with relatively high ash melting temperatures, the intensity of the diffraction lines for mullite under reducing condition is high while for the samples with relatively low ash melting temperature the intensity for anorthite is high.

  8. Chemical changes in different types of coal ash during prolonged, large scale, contact with seawater

    Energy Technology Data Exchange (ETDEWEB)

    Shoham-Frider, E.; Shelef, G.; Kress, N. [Nationall Institute of Oceanography, Haifa (Israel)

    2003-07-01

    The chemical changes occurring in coal ash exposed to prolonged (300 days), large scale, contact with running seawater were followed. Four major components (Al, Ca, Mg, Fe) and seven minor and trace elements (Cd, Cr, Cu, Mn, Zn, Pb, Hg) were measured in four coal ash types: fly and bottom ash freshly obtained from coal-fired power plant, and old ash (crushed and blocks) recovered from the sea after 3-5 years contact with seawater. Changes occurred in the chemical composition of the coal ash along the experiment: Fe increased in fresh ash, Al increased in old ash and Ca increased in all ash types except old ash blocks. Cu and Hg decreased in fresh fly ash while Cr increased, Cd decreased in all ash types except bottom ash, and Mn decreased in bottom ash. Most of the changes occurred in the fresh fly ash, and not in the old ash, indicating equilibrium after prior exposure to seawater. In addition, more changes occurred in fresh fly ash than in bottom ash, emphasizing the differences between the two ash types. While the changes in the concentrations of the major elements may be an indication of the integrity of the ash matrix, the only elements of environmental significance released to the environment were Hg and Cd. However, calculated seawater concentrations were much lower than seawater quality criteria and therefore the coal ash was considered suitable for marine applications concerning seawater quality.

  9. Ash transformation in suspension fired boilers co-firing coal and straw

    DEFF Research Database (Denmark)

    Zheng, Yuanjing; Jensen, Peter Arendt; Jensen, Anker Degn

    In this literature report is provided a status for the present knowledge level on ash properties when co-firing coal and biomass. The fly ash formed in boilers using co-firing of coal and straw do have a large influence on ash deposit formation, boiler corrosion, fly ash utilization and operation...

  10. Synthesis of high ion exchange zeolites from coal fly ash

    OpenAIRE

    Ayora, Carlos; Querol, Xavier; Moreno, N.; Alastuey, Andrés; Juan Mainar, Roberto; Andrés Gimeno, José Manuel; López Soler, Ángel; Medinaceli, Alejandro; Valero, Antonio

    2007-01-01

    This study focuses on the synthesis at a pilot plant scale of zeolitic material obtained from the coal fly ashes of the Teruel and Narcea power plants in Spain. After the optimisation of the synthesis parameters at laboratory scale, the Teruel and Narcea fly ashes were selected as low and high glass fly ashes. The pilot plant scale experiments were carried out in a 10 m3 reactor of Clariant SA (Barcelona, Spain). The results allowed obtaining 1.1 and 2.2 tonnes of zeolitic material with 40 an...

  11. Usage of fly ash as a coal desulphurization reagent

    Energy Technology Data Exchange (ETDEWEB)

    Yaman, S.; Kuecuekbayrak, S. [Istanbul Technical Univ. (Turkey). Chemical and Metallurgical Engineering Faculty

    1996-12-31

    This paper covers the direct usage of fly ash to remove sulphur from coal. Experiments were carried out on a high sulphur Turkish lignite. 5 g of fly ash was extracted in 200 ml of water under pressure and the dilute solution containing water extractable parts of fly ash was used as desulphurization reagent. Oxygen pressure was created over desulphurization medium during the extraction period by which dissolved oxygen was concentrated in the solution. Effects of temperature, partial pressure of oxygen, and time were investigated in the ranges of 403--498 K, 0.0--1.5 MPa and 15--90 min, respectively.

  12. Hydration of Hybrid Alkaline Cement Containing a Very Large Proportion of Fly Ash: A Descriptive Model

    Directory of Open Access Journals (Sweden)

    Inés Garcia-Lodeiro

    2016-07-01

    Full Text Available In hybrid alkaline fly ash cements, a new generation of binders, hydration, is characterized by features found in both ordinary portland cement (OPC hydration and the alkali activation of fly ash (AAFA. Hybrid alkaline fly ash cements typically have a high fly ash (70 wt % to 80 wt % and low clinker (20 wt % to 30 wt % content. The clinker component favors curing at ambient temperature. A hydration mechanism is proposed based on the authors’ research on these hybrid binders over the last five years. The mechanisms for OPC hydration and FA alkaline activation are summarized by way of reference. In hybrid systems, fly ash activity is visible at very early ages, when two types of gel are formed: C–S–H from the OPC and N–A–S–H from the fly ash. In their mutual presence, these gels tend to evolve, respectively, into C–A–S–H and (N,C–A–S–H. The use of activators with different degrees of alkalinity has a direct impact on reaction kinetics but does not modify the main final products, a mixture of C–A–S–H and (N,C–A–S–H gels. The proportion of each gel in the mix does, however, depend on the alkalinity generated in the medium.

  13. Cleaner phosphogypsum, coal combustion ashes and waste incineration ashes for application in building materials: A review

    Energy Technology Data Exchange (ETDEWEB)

    L. Reijnders [University of Amsterdam, Amsterdam (Netherlands)

    2007-02-15

    Application of phosphogypsum, coal combustion ashes and waste incineration ashes in building materials has been limited by the presence of minor components that are hazardous, such as radioactive substances, chlorinated dioxins and heavy metals, or have a negative impact on product quality or production economics, such as phosphate, fluoride, carbon and chloride. Source reduction, destruction of persistent organics and separation techniques may reduce the concentrations of such components. With a few exceptions, separation techniques currently lead to significantly higher (private) costs. Higher waste disposal costs, tighter regulations and higher prices for competing virgin minerals could make the use of the purified phosphogypsum and ashes in building materials more attractive.

  14. Release of mercury vapor from coal combustion ash.

    Science.gov (United States)

    Heebink, Loreal V; Hassett, David J

    2002-08-01

    The long-term stability of Hg in coal combustion by-products (CCBs) was evaluated at ambient and near-ambient temperatures. Six CCB samples with atypically high levels of total Hg were selected for study assuming a greater potential for release of measurable amounts of Hg vapor. The samples selected included two fly ash samples from U.S. eastern bituminous coal, two fly ash samples from South African low-rank coal, one fly ash from Powder River Basin (PRB) subbituminous coal blended with petroleum coke, and one PRB subbituminous coal fly ash incorporated with flue gas desulfurization material. Air scrubbed of Hg was passed through compacted 100-g aliquots of each sample at 1 mL/min and vented to a gold-coated quartz trap to collect released Hg vapor. The samples were maintained at ambient and near-ambient (37 degrees C) temperatures. All samples released low-picogram levels of Hg after 90 days. No pattern was evident to link the total Hg content to the rate of release of Hg vapor. An average of 0.030 pg Hg/g CCB/day was released from the samples, which equates to 2.2 x 10(-8) lb Hg/ton CCB/year. If this were applied to a coal-fired power plant production of 200,000 tons of fly ash per year, there would be a maximum potential release of 0.0044 lb, or 2.00 g, of Hg per year. Experiments are continuing to determine long-term vapor release of Hg from CCBs. All samples have been set up in duplicate at ambient temperature with an improved apparatus to reevaluate results reported in this article. PMID:12184691

  15. Study of the correlation between the coal calorific value and coal ash content using X-ray fluorescence analysis

    International Nuclear Information System (INIS)

    In this paper we have studied the possibility of determining the chemical elements in coal samples using X-ray fluorescence analysis and have found a relationship between the coal calorific value and its ash content with the coal moisture accounting. The amount of coal ash can be determined by the content of the basic chemical elements, such as Si, Sr, Fe, and Ca. It was concluded that the calorific value of coal can be estimated from the ash content in coal without the calorimetric measurements. These correlation coefficients were calculated for several coal mines in Mongolia. The results are in good agreement with the results of chemical analysis

  16. Agricultural uses of alkaline fluidized bed combustion ash: case studies

    Energy Technology Data Exchange (ETDEWEB)

    Stout, W.L.; Daily, M.R.; Nickeson, T.L.; Svendson, R.L.; Thompson, G.P. [USDA-ARS, University Park, PA (United States)

    1997-06-01

    Successful programmes were developed by Ahlstrom Development Ash Corporation and Air Products and Chemical for using fluidized bed combustion ash as a substitute for agricultural lime on dairy farms in northern New York state and on fruit and nut crops in the San Joaquin Valley of California. The companies developed these programmes by utilizing the methodology developed through USDA-ARS research and working closely with agricultural consultants and regulatory agencies to ensure that the ash applications were both agronomically and environmentally sound. 1 ref.

  17. Production of ceramics from coal fly ash

    Directory of Open Access Journals (Sweden)

    Angjusheva Biljana

    2012-01-01

    Full Text Available Dense ceramics are produced from fly ash from REK Bitola, Republic of Macedonia. Four types of fly ash from electro filters and one from the collected zone with particles < 0.063 mm were the subject of this research. Consolidation was achieved by pressing (P= 133 MPa and sintering (950, 1000, 1050 and 11000C and heating rates of 3 and 100/min. Densification was realized by liquid phase sintering and solid state reaction where diopside [Ca(Mg,Al(Si,Al2O6] was formed. Ceramics with optimal properties (porosity 2.96±0.5%, bending strength - 47.01±2 MPa, compressive strength - 170 ±5 MPa was produced at 1100ºC using the heating rate of 10ºC/min.

  18. Hierarchical zeolites from class F coal fly ash

    Science.gov (United States)

    Chitta, Pallavi

    Fly ash, a coal combustion byproduct is classified as types class C and class F. Class C fly ash is traditionally recycled for concrete applications and Class F fly ash often disposed in landfills. Class F poses an environmental hazard due to disposal and leaching of heavy metals into ground water and is important to be recycled in order to mitigate the environmental challenges. A major recycling option is to reuse the fly ash as a low-cost raw material for the production of crystalline zeolites, which serve as catalysts, detergents and adsorbents in the chemical industry. Most of the prior literature of fly ash conversion to zeolites does not focus on creating high zeolite surface area zeolites specifically with hierarchical pore structure, which are very important properties in developing a heterogeneous catalyst for catalysis applications. This research work aids in the development of an economical process for the synthesis of high surface area hierarchical zeolites from class F coal fly ash. In this work, synthesis of zeolites from fly ash using classic hydrothermal treatment approach and fusion pretreatment approach were examined. The fusion pretreatment method led to higher extent of dissolution of silica from quartz and mullite phases, which in turn led to higher surface area and pore size of the zeolite. A qualitative kinetic model developed here attributes the difference in silica content to Si/Al ratio of the beginning fraction of fly ash. At near ambient crystallization temperatures and longer crystallization times, the zeolite formed is a hierarchical faujasite with high surface area of at least 360 m2/g. This work enables the large scale recycling of class F coal fly ash to produce zeolites and mitigate environmental concerns. Design of experiments was used to predict surface area and pore sizes of zeolites - thus obviating the need for intense experimentation. The hierarchical zeolite catalyst supports tested for CO2 conversion, yielded hydrocarbons

  19. Composition, diagenetic transformation and alkalinity potential of oil shale ash sediments

    International Nuclear Information System (INIS)

    Oil shale is a primary fuel in the Estonian energy sector. After combustion 45-48% of the oil shale is left over as ash, producing about 5-7 Mt of ash, which is deposited on ash plateaus annually almost without any reuse. This study focuses on oil shale ash plateau sediment mineralogy, its hydration and diagenetic transformations, a study that has not been addressed. Oil shale ash wastes are considered as the biggest pollution sources in Estonia and thus determining the composition and properties of oil shale ash sediment are important to assess its environmental implications and also its possible reusability. A study of fresh ash and drillcore samples from ash plateau sediment was conducted by X-ray diffractometry and scanning electron microscopy. The oil shale is highly calcareous, and the ash that remains after combustion is derived from the decomposition of carbonate minerals. It is rich in lime and anhydrite that are unstable phases under hydrous conditions. These processes and the diagenetic alteration of other phases determine the composition of the plateau sediment. Dominant phases in the ash are hydration and associated transformation products: calcite, ettringite, portlandite and hydrocalumite. The prevailing mineral phases (portlandite, ettringite) cause highly alkaline leachates, pH 12-13. Neutralization of these leachates under natural conditions, by rainwater leaching/neutralization and slow transformation (e.g. carbonation) of the aforementioned unstable phases into more stable forms, takes, at best, hundreds or even hundreds of thousands of years.

  20. JV Task 6 - Coal Ash Resources Research Consortium Research

    Energy Technology Data Exchange (ETDEWEB)

    Debra Pflughoeft-Hassett; Tera Buckley; Bruce Dockter; Kurt Eylands; David Hassett; Loreal Heebink; Erick Zacher

    2008-04-01

    The Coal Ash Resources Research Consortium{reg_sign} (CARRC{reg_sign}, pronounced 'cars') focuses on performing fundamental and applied scientific and engineering research emphasizing the environmentally safe, economical use of coal combustion by-products (CCBs). CARRC member organizations, which include utilities and marketers, are key to developing industry-driven research in the area of CCB utilization and ensuring its successful application. The U.S. Department of Energy is a partner in CARRC through the EERC Jointly Sponsored Research Program (JSRP), which provides matching funds for industrial member contributions and facilitates an increased level of effort in CARRC. CARRC tasks were designed to provide information on CCB performance, including environmental performance, engineering performance, favorable economics, and improved life cycle of products and projects. CARRC technical research tasks are developed based on member input and prioritization. CARRC special projects are developed with members and nonmembers to provide similar information and to support activities, including the assembly and interpretation of data, support for standards development and technology transfer, and facilitating product development and testing. CARRC activities from 1998 to 2007 included a range of research tasks, with primary work performed in laboratory tasks developed to answer specific questions or evaluate important fundamental properties of CCBs. CARRC topical reports were prepared on several completed tasks. Specific CARRC 1998B2007 accomplishments included: (1) Development of several ASTM International Standard Guides for CCB utilization applications. (2) Organization and presentation of training courses for CCB professionals and teachers. (3) Development of online resources including the Coal Ash Resource Center, Ash from Biomass in Coal (ABC) of cocombustion ash characteristics, and the Buyer's Guide to Coal-Ash Containing Products. In addition

  1. Elemental characterization of coal, fly ash, and bottom ash using an energy dispersive X-ray fluorescence technique

    International Nuclear Information System (INIS)

    A total of 18 elements viz. Si, Al, Fe, Ca, Mg, K, Na, Sr, V, Zn, Mn, Cr, Cu, Pb, Ni, Co, As and Cd were analyzed in coal, fly ash and bottom ash samples collected across India using an EDXRF technique. Various indices such as element enrichment ratio, enrichment factor (with respect to crustal average) and mineral composition were calculated. Around 95% of mass was reconstructed using the concentration of elements in this study for fly and bottom ash. - Highlights: • Concentrations of 18 elements were determined in coal and ash samples using EDXRF. • Mineral quantification up to 95% was carried out for fly and bottom ash samples. • Enrichment ratios of elements were calculated in combustion residue with respect to coal. • Enrichment factor with respect to crustal average was estimated for ash samples

  2. From in-situ coal to fly ash: A study of coal mines and power plants from Indiana

    Science.gov (United States)

    Mastalerz, Maria; Hower, J.C.; Drobniak, A.; Mardon, S.M.; Lis, G.

    2004-01-01

    This paper presents data on the properties of coal and fly ash from two coal mines and two power plants that burn single-source coal from two mines in Indiana. One mine is in the low-sulfur (5%) Springfield Coal Member of the Petersburg Formation (Pennsylvanian). Both seams have comparable ash contents (???11%). Coals sampled at the mines (both raw and washed fractions) were analyzed for proximate/ultimate/sulfur forms/heating value, major oxides, trace elements and petrographic composition. The properties of fly ash from these coals reflect the properties of the feed coal, as well as local combustion and post-combustion conditions. Sulfur and spinel content, and As, Pb and Zn concentrations of the fly ash are the parameters that most closely reflect the properties of the source coal. ?? 2004 Elsevier B.V. All rights reserved.

  3. Mobility and speciation of arsenic in the coal fly ashes collected from the Savannah River Site (SRS).

    Science.gov (United States)

    Liu, Guangliang; Cai, Yong; Hernandez, Damaris; Schrlau, Jill; Allen, Marshall

    2016-05-01

    Arsenic (As) leaching from coal fly ash stockpiled at waste disposal sites is a source of environmental concern. An array of techniques including batch extraction and column leaching tests, in combination with speciation analysis of chemically specific As species, was employed to evaluate the mobility of As in fly ashes collected from the U.S. DOE Savannah River Site. The results obtained using the U.S. EPA Toxicity Characteristic Leaching Procedure (TCLP), a two-step sequential extraction technique, and continuous column leaching experiments suggest that only a small portion of total As in the fly ashes was mobile, but mobilizable As could be a considerable fraction (3.1-43%), varying inversely with alkalinity of fly ash. Speciation analysis by using phosphate extraction suggests that arsenate (As(V)) was the major extractable species in the fly ash samples. During the column leaching experiment, however, it was observed that arsenite (As(III)) was an important species leached out of the fly ashes, indicating species conversion during the leaching process. The matrix-bound As(V) within the fly ash, once being released from the solid matrix, could be converted to As(III) during its transport inside the column. The pHs of leachates and fly ashes (both acidic in column leaching experiments here) could be related to the dominance of As(III) in the effluents. PMID:26933905

  4. On stream ash analysis of coal based on its natural gamma-ray activity

    International Nuclear Information System (INIS)

    A novel method based on the natural gamma-ray activity of coal has been developed for the on-stream determination of ash. The accuracy of the method has been verified by measuring the natural gamma-ray activity and ash content of coal samples from a number of locations in New Zealand and Australia. The rms differences between % ash by ignition and % ash by the gamma-ray method ranged from 0.65% ash for coal samples from a Queensland mine to 1.6% ash for samples from a southern New South Wales mine. The rms errors include those to geovariance, and due to sampling and sample analysis by conventional means. The error in ash measurement by the gamma-ray method can therefore be reduced by substantially eliminating these errors. A prototype ash analyser was also developed and field-tested at the Huntly East mine. In a four-week test, the prototype gauge was used to determine the ash content of run-of-mine (rom) coal below 20% ash to within +- 1.7% ash. Laboratory studies of coal samples collected during the field test of the prototype gave an error of 0.8% ash for coal samples below 20% ash content. A higher error was observed in the field test compared with laboratory data, and the difference is attributed to errors in sampling from the conveyor belt

  5. Characteristics of Coal Ashes in Yanzhou Mining District and Distribution of Trace Elements in Them

    Institute of Scientific and Technical Information of China (English)

    刘桂建; 彭子成; 杨萍玥; 桂和荣; 王桂梁

    2001-01-01

    In the process of combustion of coal organic and inorganic materials in it will undergo a complex variation. Part of them will become volatiles and, together with coal smoke, enter into atmosphere, some will remain in micro-particulates such as ash and dust and find their way into atmosphere in the form of solid particles, and the rest will be retained in ash and slag. Coal ashes are the residues of organic and inorganic substances in coal left after coal combustion and the composition of coal ashes is dependent on that of minerals and organic matter in coal This paper deals with the chemical composition of coal ashes, the distribution of trace elements in them and their petrological characteristics, and also studies the relationship between the yield of coal ashes and the distribution of trace elements. In addition, a preliminary study is also under taken on the factors that affect the chemical composition of coal ashes. As viewed from the analyses of coal ash samples collected from the Yanzhou mining district, it can be seen clearly that coal ashes from the region studied are composed chiefly of crystalline materials, glassy ma terials and uncombusted organic matter and the major chemical compositions are SiO2, A12O3,Fe2O3, and CaO, as well as minor amounts of SO3, P2O5, Na2O, K2O and TiO2. During the combustion of coal, its trace elements will be redistributed and most of them are enriched in coal ashes. At the same time, the concentrations of the trace elements in flying ash are much higher than those of bottom ash, i.e. , with decreasing particle-size of coal ashes their concen trations will become higher and higher. So the contents of trace elements are negatively propor tional to the particle-size of coal ashes. There has been found a positive correlation between the trace elements Th, V, Zn, Cu and Pb and the yield of coal ashes while a negative correlation between C1 and the yield of coal ashes.

  6. Evaluation and Treatment of Coal Fly Ash for Adsorption Application

    Directory of Open Access Journals (Sweden)

    Samson Oluwaseyi BADA

    Full Text Available Many researchers had investigated fly ash as an adsorbent for the uptake of organic compounds from petrochemical waste effluents. The availability, inexpensive and its adsorption characteristic had made it an alternative media for the removal of organic compounds from aqueous solution. The physical property of South African Coal Fly Ash (SACFA was investigated to determine its adsorption capability and how it can be improved. Chemical treatment using 1M HCl solution in the ratio of (1 g fly ash to (2 ml of acid was used and compared with untreated heat-treated samples. The chemically treated fly ash has a higher specific surface area of 5.4116 m2/g than the heat-treated fly ash with 2.9969 m2/g. More attention had to be given to the utilization of SACFA for the treatment of wastewaters containing organic compounds through the application of Liquid phase adsorption process that was considered as an inexpensive and environmentally friendly technology.

  7. Properties of Concrete using Tanjung Bin Power Plant Coal Bottom Ash and Fly Ash

    Directory of Open Access Journals (Sweden)

    Abdulhameed Umar Abubakar

    2012-12-01

    Full Text Available Coal combustion by-products (CCPs have been around since man understood that burning coal generates electricity, and its utilization in concrete production for nearly a century. The concept of sustainable development only reawaken our consciousness to the huge amount of CCPs around us and the need for proper reutilization than the current method of disposal which has  severe consequences both to man and the environment. This paper presents the result of utilization of waste from thermal power plants to improve some engineering properties of concrete. Coal bottom ash (CBA and fly ash were utilized in partial replacement for fine aggregates and cement respectively. The results of compressive strength at 7, 28, 56 & 90 days curing are presented because of the pozzolanic reaction. Other properties investigated include physical properties, fresh concrete properties and density. The results showed that for a grade 35 concrete with a combination of CBA and fly ash can produce 28 day strength above 30 MPa.

  8. Alkaline bioleaching of municipal solid waste incineration fly ash by autochthonous extremophiles.

    Science.gov (United States)

    Ramanathan, Thulasya; Ting, Yen-Peng

    2016-10-01

    The increasing demand for energy and the generation of solid waste have caused an alarming rise in fly ash production globally. Since heavy metals continue to be in demand for the production of materials, resource recovery from the recycling of these wastes has the potential to delay the depletion of natural ores. The use of microorganisms for the leaching of metals, in a process called bioleaching, is an eco-friendly and economical way to treat the metal-laden wastes. Bioleaching of fly ash is challenging due largely to the alkaline nature and toxic levels of heavy metals which are detrimental to microbial growth and bioleaching activity. The present work reports the isolation of indigenous bacteria from a local fly ash landfill site and their bioleaching performance. 38 autochthonous strains of bacteria were isolated from eight samples collected and plated on five different media. 18 of the isolates showed bioleaching potential, with significant alkaline pH or fly ash tolerance. Genetic characterization of the strains revealed a dominance of Firmicutes, with Alkalibacterium sp. TRTYP6 showing highest fly ash tolerance of up to 20% w/v fly ash, and growth over a pH range 8-12.5. The organism selectively recovered about 52% Cu from the waste. To the best of our knowledge, this is the first time a study on bioleaching with extreme alkaliphiles is reported. PMID:27362528

  9. Potential application of coal-fuel oil ash for the manufacture of building materials.

    Science.gov (United States)

    Cioffi, R; Marroccoli, M; Sansone, L; Santoro, L

    2005-09-30

    In this paper coal-fuel oil ash has been characterized in terms of leaching behaviour and reactivity against lime and gypsum in hydratory systems for the manufacture of building materials. Its behaviour was also compared to that of coal ash. Metal release was measured in a dynamic leaching test with duration up to 16 days. The results have shown that coal-fuel oil ash behaves very similarly to coal ash. The reactivity of coal-fuel oil ash against lime and gypsum was measured in mixtures containing only lime and in mixtures containing both lime and gypsum. These systems were hydrated at 25 and 40 degrees C under 100% R.H. The results have shown that the main hydration products are the same as those that are usually formed in similar coal ash-based systems. That is, calcium silicate hydrate in coal-fuel oil ash/lime systems and calcium silicate hydrate plus calcium trisulphoaluminate hydrate in coal-fuel oil ash/lime/gypsum systems. From the quantitative point of view, hydration runs showed that the amounts of both chemically combined water and reacted lime measured in the case under investigation are very similar to those found in similar coal ash-based systems. Finally, the measurement of unconfined compressive strength proved that the systems have potentiality for the manufacture of pre-formed building blocks. PMID:15985327

  10. Stimulation of Mercury Methylation by Coal Ash in Anaerobic Sediment Microcosms

    Science.gov (United States)

    Schwartz, G.; Hsu-Kim, H.; Redfern, L.; Gunsch, C.; Vengosh, A.

    2015-12-01

    Coal combustion products (coal ash) represent one of the largest industrial waste streams in the United States. Coal ash contains elevated levels of toxic, bioaccumulative elements such as mercury (Hg), yet the majority of coal ash waste is stored in unlined impoundments and landfills. These impoundments have a long history of environmental degradation, including: groundwater contamination, surface water contamination through impoundment effluent discharge, and impoundment failures resulting in catastrophic ash release events. The fate of toxic elements associated with coal ash is greatly influenced by environmental parameters, such as redox potential and microbial activity, which induce transformations and leaching of contaminants. Here we used anaerobic sediment-ash microcosms to determine how coal ash impacts methyl mercury (MeHg) production in a simulated benthic aquatic environment. We used two coal ash types in the microcosms: a weathered ash with low sulfate/Hg content and a fresh fly ash that was relatively enriched in sulfate/Hg compared to the weathered ash. Two different sediments were used in the microcosms: one was a pristine sediment (containing 0.03 mg/kg Hg) and the other was a relatively Hg-contaminated sediment (containing 0.29 mg/kg Hg). Results showed that microcosms amended with the low sulfate/low Hg ash had no net MeHg production. In contrast, microcosms amended with high sulfate/high Hg ash showed increases in MeHg concentrations that were 2 to 3 times greater than control microcosms without ash, indicating that coal ash can stimulate MeHg production by providing spikes of Hg and labile sulfate to the aquatic system. MeHg production in ash-amended microcosms containing contaminated sediment was no greater than in the ash-amended pristine sediment microcosms. This may indicate that Hg associated with coal ash is more bioavailable than the Hg present in historically contaminated sediments. Illumina sequencing is underway to investigate the

  11. Direct Quantitative Analysis of Arsenic in Coal Fly Ash

    Directory of Open Access Journals (Sweden)

    Sri Hartuti

    2012-01-01

    Full Text Available A rapid, simple method based on graphite furnace atomic absorption spectrometry is described for the direct determination of arsenic in coal fly ash. Solid samples were directly introduced into the atomizer without preliminary treatment. The direct analysis method was not always free of spectral matrix interference, but the stabilization of arsenic by adding palladium nitrate (chemical modifier and the optimization of the parameters in the furnace program (temperature, rate of temperature increase, hold time, and argon gas flow gave good results for the total arsenic determination. The optimal furnace program was determined by analyzing different concentrations of a reference material (NIST1633b, which showed the best linearity for calibration. The optimized parameters for the furnace programs for the ashing and atomization steps were as follows: temperatures of 500–1200 and 2150°C, heating rates of 100 and 500°C s−1, hold times of 90 and 7 s, and medium then maximum and medium argon gas flows, respectively. The calibration plots were linear with a correlation coefficient of 0.9699. This method was validated using arsenic-containing raw coal samples in accordance with the requirements of the mass balance calculation; the distribution rate of As in the fly ashes ranged from 101 to 119%.

  12. Prevention of trace and major element leaching from coal combustion products by hydrothermally-treated coal ash

    Energy Technology Data Exchange (ETDEWEB)

    Adnadjevic, B.; Popovic, A.; Mikasinovic, B. [University of Belgrade, Belgrade (Serbia). Dept. of Chemistry

    2009-07-01

    The most important structural components of coal ash obtained by coal combustion in 'Nikola Tesla A' power plant located near Belgrade (Serbia) are amorphous alumosilicate, alpha-quartz, and mullite. The phase composition of coal ash can be altered to obtain zeolite type NaA that crystallizes in a narrow crystallization field (SiO{sub 2}/Al{sub 2}O{sub 3}; Na{sub 2}O/SiO{sub 2}; H{sub 2}O/Na{sub 2}O ratios). Basic properties (crystallization degree, chemical composition, the energy of activation) of obtained zeolites were established. Coal ash extracts treated with obtained ion-exchange material showed that zeolites obtained from coal ash were able to reduce the amounts of iron, chromium, nickel, zinc, copper, lead, and manganese in ash extracts, thus proving its potential in preventing pollution from dump effluent waters.

  13. Status of coal ash corrosion resistant materials test program

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, D.K.; Meisenhelter, D.K.; Sikka, V.K.

    1999-07-01

    In November of 1998, Babcock and Wilcox (B and W) began development of a system to permit testing of several advanced tube materials at metal temperatures typical of advanced supercritical steam conditions of 1100 F and higher in a boiler exhibiting coal ash corrosive conditions. The U.S. Department of Energy (DOE), the Ohio Coal Development Office (OCDO), B and W, and First Energy's Ohio Edison jointly fund the project. CONSOL Energy Company is also participating as an advisor. Several materials producers including Oak Ridge National Laboratory (ORNL) contributed advanced materials to the project. The coal-ash corrosion resistant materials test program will provide full scale, in-situ testing of recently developed boiler superheater and reheater tube materials. These newer materials may be capable of operating at higher steam temperatures while resisting external/fire-side corrosion. For high sulfur coal applications, this is a key issue for advanced cycle pulverized coal-fired plants. Fireside corrosion is also a critical issue for many existing plants. Previous testing of high temperature materials in the United States has been based primarily on using laboratory test coupons. The test coupons did not operate at conditions representative of a high sulfur coal-fired boiler. Testing outside of the United States has been with low sulfur coal or natural gas firing and has not addressed corrosion issues. This test program takes place in an actual operating boiler and is expected to confirm the performance of these materials with high sulfur coal. The system consists of three identical sections, each containing multiple pieces of twelve different materials. They are cooled by reheater steam, and are located just above the furnace exit in Ohio Edison's Niles Unit No.1, a 110 MWe unit firing high sulfur Ohio coal. After one year of operation, the first section will be removed for thorough metallurgical evaluation. The second and third sections will operate for

  14. Self-cementing Mechanism of CFBC Coal Ashes at Early Ages

    Institute of Scientific and Technical Information of China (English)

    SONG Yuanming; QIAN Jueshi; WANG Zhi; WANG Zhijuan

    2008-01-01

    The self-cementing mechanism at early ages of circulating fluidized bed combustion (CFBC) coal ashes was studied by X-ray diffraction (XRD), infrared (IR) spectroscopy and chemical method. The results indicate that the amorphous phase is predominant in CFBC coal ashes. The polymerization degree of [SiO4] and [AlO6] of CFBC desulphurization coal ashes is lower than that of those without desulphurization. The contents of the components with fast hydration rate of CFBC desulphurization coal ashes are significantly greater than those of the ashes without desulphurization. This work confirms that the amorphous minerals with high chemical activity are the main causes of the self-cementing property of CFBC desulphurization coal ashes at early ages.

  15. Application of coal ash to environmental improvement Transformation into zeolite, potassium fertilizer, and FGD absorbent

    OpenAIRE

    Kikuchi, R.

    1999-01-01

    http://www.elsevier.com/locate/issn/09213449 The rapid increase in population and economic growth have led to an increase in energy demand. Coal reserves are distributed worldwide, and coal is now known to be the most stable and available energy source. However, utilization of coal as an energy source involves the generation of a great amount of coal ash, and the recycling rate of the ash is rather low. Coal ash is mainly used in civil construction materials, and there is a lim...

  16. Environmental impact of manganese due to its leaching from coal fly ash.

    Science.gov (United States)

    Prasad, Bably; Mondal, Kajal K R

    2009-01-01

    In India, so far not much efforts have been made to use coal ash as backfill material in underground/ open cast mines and to predict its subsequent effect on ground water quality. One of the main problems in disposing of big quantities of coal ash is the possible leaching of different pollutants, including manganese. A thorough investigation regarding leaching of manganese from different fly ashes is required to know the impact of manganese due to its leaching from fly ash to ground water as well as surface water. In the present study, short term and long term leaching studies have been carried out on fly ash, bottom ash, pond ash and weathered ash of Chandrapura thermal power plant, Bokaro, Jharkhand and Ramagundam thermal power plant, Ramagundam, Andhra Pradesh. The amount of manganese released in different experiments has been evaluated. The leachate of Chandrapura fly ash has more manganese concentration (0.2001 mg/L) than the leachate of bottom ash, pond ash and weathered ash. A field investigation at Damoda abandoned open cast mine, filled with pond ash of Chandrapura thermal power plant revealed that concentration of manganese in ground water beneath the ash filled mine has been found very high (maximum up to 6.0 mg/L). But its migration to a long distance has not been seen. Remedial measures for coal ash disposal have also been formulated.

  17. The Use of Coal Bottom Ash In Hot Mix Asphalt

    Directory of Open Access Journals (Sweden)

    Charles Begyina Kodjo Nketsiah

    2015-05-01

    Full Text Available Bottom ash is a waste material from coal burnt to generate electric power. It is incombustible and non-biodegradable; hence, the best way to dispose it is by recycling rather than incineration and land filling. Past research on bottom ash in road building have focused mainly on embankment filling, sub-base and base courses; except boiler slag which has received much attention in Hot Mix Asphalt (HMA. Bottom ash from Tanjung Bin Power Station was thus investigated through laboratory testing to justify its use in HMA construction in Malaysia. This Paper analysed the data with regards to performance in HMA. In the Marshall Mix design, the material largely satisfied the Stability, Flow and Stiffness requirements which were comparable to that of conventional aggregates, although void contents were a bit higher. When blended with granite, all the parameters were met. Contrary to past suggestions that bottom ash in HMA consumes more bitumen, the 6.4% (51.20g Optimum Bitumen Content (OBC achieved in this study does not necessarily translate into high consumption, compared to OBC of 5.3% (59.63g in the case of granite. The HMA also proved to be highly resistant to moisture-induced damage and satisfied the minimum JKR specification for Static Uniaxial Load Strain.

  18. Sintered coal ash/flux materials for building materials

    Energy Technology Data Exchange (ETDEWEB)

    Dry, C.; Meier, J.; Bukowski, J. [University of Illinois, Urbana, IL (United States). School of Architecture

    2004-03-01

    An Illinois coal ash, which has metals and a large amount of iron, is considered to be an especially difficult waste for disposal. In the process described in this paper, the high iron and metal content is used to create a building material with special properties. The metals are sequestered. The metals allow a process that creates value-added products, building materials. The products are inexpensively prepared colored, strong, lightweight insulative structural panels. By either sintering in an oven at 725{sup o}C or by adding a flux and sintering at 525{sup o}C, panels are produced which will not leach metals from the ash. The use of an acid with the fly ash as a flux was investigated in comparison with fly ash control samples. The effects of sintering samples at different temperatures and with or without vacuum were also observed. Properties of the samples, including values for strength, water absorption, insulation, and color, are presented from this study.

  19. Investigation of the potential of coal combustion fly ash for mineral sequestration of CO2 by accelerated carbonation

    International Nuclear Information System (INIS)

    Mineral carbonation of alkaline waste materials is being studied extensively for its potential as a way of reducing the increased level of CO2 in the atmosphere. Carbonation converts CO2 into minerals which are stable over geological time scales. This process occurs naturally but slowly, and needs to be accelerated to offset the present rate of emissions from power plants and other emission sources. The present study attempts to identify the potential of coal fly ash as a source for carbon storage (sequestration) through ex-situ accelerated mineral carbonation. In the study, two operational parameters that could affect the reaction process were tested to investigate their effect on mineralization. Coal fly ash was mixed with water to different water-to-solid ratios and samples were carbonated in a pressure vessel at different initial CO2 pressures. Temperature was kept constant at 40 °C. According to the results, one ton of Hazelwood fly ash could sequester 7.66 kg of CO2. The pressure of CO2 inside the vessel has an effect on the rate of CO2 uptake and the water-to-solid ratio affects the weight gain after the carbonation of fly ash. The results confirm the possibility of the manipulation of process parameters in enhancing the carbonation reaction. - Highlights: ► Mineral sequestration CO2 by of coal fly ash is a slow process under ambient conditions. ► It can be accelerated by manipulating the process parameters inside a reactor. ► Initial CO2 pressure and water to solid mixing ratio inside the reactor are two of those operational parameters. ► According to the test results higher CO2 initial pressure gives higher on rates of CO2 sequestration. ► Water to fly ash mixing ratio effect on amount of CO2 sequestered into fly ash

  20. Effects of the addition of oil shale ash and coal ash on physic-chemical properties of CPJ45 cement

    Directory of Open Access Journals (Sweden)

    Nabih K.

    2014-04-01

    Full Text Available We focused our research on recycling industrial wastes, fly ash (F.A, bottom ash (B.A and oil shale ash (S.A in cement production. The study concerns physico-chemical characterization of these products and the influence of their addition on the mechanical proprieties of the CPJ45 cement. XRF allowed us to rank the three additives used according to their contents on major oxides. Coal ashes belong to the class F, and thus possess poozzolanic properties and oil shale ash belongs to the class C and possesses hydraulic and poozolanic properties. The crystalline phases constituting each ash were analysed by XRD. We observe in bottom ash the presence of quartz and mullite. The same crystals are found in fly ash with hematite and magnetite. Oil shale ash is composed of quartz, anhydrite, gehlenite, wollastonite and periclase. The microstructures of fly ash and bottom ash were studied using SEM. The bottom ash was composed respectively of fine particles that are generally irregularly shaped, their dimensions are between 5 and 28μm and of big particles(300 μm. The EDX analysis coupled with an electronic microscope provided some information about the major elements that constitute our samples. The dehydrations of anhydrous and three days hydrated cement were examined by DSC. For hydrated cements we noticed endothermic peaks related to the dehydration of CSH, CH and decomposition of carbonates. The study of the mechanical properties of CPJ45 cement by adding different proportions of fly ash, bottom ash and oil shale ash helped clarifying the percentage of ash that leaded to improve the 28 days mechanical strength. The results show that the cements studied have their maximum mechanical resistance with the addition at 7% of fly ash or 10% of oil shale ash.

  1. Material and structural characterization of alkali activated low-calcium brown coal fly ash.

    Science.gov (United States)

    Skvára, Frantisek; Kopecký, Lubomír; Smilauer, Vít; Bittnar, Zdenek

    2009-09-15

    The waste low-calcium Czech brown coal fly ash represents a considerable environmental burden due to the quantities produced and the potentially high content of leachable heavy metals. The heterogeneous microstucture of the geopolymer M(n) [-(Si-O)(z)-Al-O](n).wH(2)O, that forms during the alkaline activation, was examined by means of microcalorimetry, XRD, TGA, DSC, MIP, FTIR, NMR MAS ((29)Si, (27)Al, (23)Na), ESEM, EDS, and EBSD. The leaching of heavy metals and the evolution of compressive strength were also monitored. The analysis of raw fly ash identified a number of different morphologies, unequal distribution of elements, Fe-rich rim, high internal porosity, and minor crystalline phases of mullite and quartz. Microcalorimetry revealed exothermic reactions with dependence on the activator alkalinity. The activation energy of the geopolymerization process was determined as 86.2kJ/mol. The X-ray diffraction analysis revealed no additional crystalline phases associated with geopolymer formation. Over several weeks, the (29)Si NMR spectrum testified a high degree of polymerization and Al penetration into the SiO(4) tetrahedra. The (23)Na NMR MAS spectrum hypothesized that sodium is bound in the form of Na(H(2)O)(n) rather than Na(+), thus causing efflorescence in a moisture-gradient environment. As and Cr(6+) are weakly bonded in the geopolymer matrix, while excellent immobilization of Zn(2+), Cu(2+), Cd(2+), and Cr(3+) are reported.

  2. Utilization of blended fluidized bed combustion (FBC) ash and pulverized coal combustion (PCC) fly ash in geopolymer.

    Science.gov (United States)

    Chindaprasirt, Prinya; Rattanasak, Ubolluk

    2010-04-01

    In this paper, synthesis of geopolymer from fluidized bed combustion (FBC) ash and pulverized coal combustion (PCC) fly ash was studied in order to effectively utilize both ashes. FBC-fly ash and bottom ash were inter-ground to three different finenesses. The ashes were mixed with as-received PCC-fly ash in various proportions and used as source material for synthesis of geopolymer. Sodium silicate (Na(2)SiO(3)) and 10M sodium hydroxide (NaOH) solutions at mass ratio of Na(2)SiO(3)/NaOH of 1.5 and curing temperature of 65 degrees C for 48h were used for making geopolymer. X-ray diffraction (XRD), scanning electron microscopy (SEM), degree of reaction, and thermal gravimetric analysis (TGA) were performed on the geopolymer pastes. Compressive strength was also tested on geopolymer mortars. The results show that high strength geopolymer mortars of 35.0-44.0MPa can be produced using mixture of ground FBC ash and as-received PCC-fly ash. Fine FBC ash is more reactive and results in higher degree of reaction and higher strength geopolymer as compared to the use of coarser FBC ash. Grinding increases reactivity of ash by means of increasing surface area and the amount of reactive phase of the ash. In addition, the packing effect due to fine particles also contributed to increase in strength of geopolymers.

  3. Mosses accumulate heavy metals from the substrata of coal ash

    Directory of Open Access Journals (Sweden)

    Vukojević Vanja

    2005-01-01

    Full Text Available Plants that are able to accumulate and tolerate extraordinarily high concentrations of heavy metals (hyperaccumulators can be used for phytoremediation (removal of contaminants from soils or phytomining (growing a crop of plants to harvest the metals. Two moss species, Bryum capillare Hedw. and Ceratodon purpureus Hedw., were tested as potential phytoremedies under in vivo conditions on a coal ash disposal site in the surroundings of Obrenovac (NW Serbia. The content of various heavy metals (iron, manganese zinc, lead, nickel, cadmium, and copper in the mosses and substrata were investigated over a period of three years. Iron and zinc were found to have the highest concentration in the mosses.

  4. Ash transformation in suspension fired boilers co-firing coal and straw

    DEFF Research Database (Denmark)

    Zheng, Yuanjing; Jensen, Peter Arendt; Jensen, Anker Degn;

    The properties of the ash from co-firing of coal and straw have a large influence on boiler operation, flue gas cleaning equipment and appropriate utilization of the fly ash. A study on the fuel composition and local conditions influence on fly ash properties has been done by making entrained flo...

  5. Self inhibition of aluminium leaching from coal fly ash by sulfuric acid

    Energy Technology Data Exchange (ETDEWEB)

    Seidel, A.; Sluszny, A.; Shelef, G.; Zimmels, Y. [Technion-Israel Institute of Technology, Haifa (Israel). Dept. of Civil Engineering

    1999-11-01

    Coal fly ash (CFA) produced by power plants in Israel is alkaline and contains aluminium that can be leached by different acids. The mechanism of aluminium leaching from CFA by sulfuric acid was investigated. It was found that higher CFA content, which indicates higher solid to liquid ratio in the leaching suspension, decreases the fraction of aluminium leached by sulfuric acid. This behavior constitutes a new unexplained phenomenon, which could not be explained by analysis of the mass action law of the dissolution reactions, but rather by mass transfer considerations. The leaching process involves a self-inhibition mechanism due to the precipitation of calcium sulfate on the surface and within the CFA particles. The effects of CFA content, acid concentration, temperature, and pre-leaching conditioning, upon leaching rates and yields, were tested.

  6. Self inhibition of aluminium leaching from coal fly ash by sulfuric acid

    Energy Technology Data Exchange (ETDEWEB)

    Seidel, A.; Sluszny, A.; Shelef, G.; Zimmels, Y. (Technion-Israel Institute of Technology, Haifa (Israel). Dept. of Civil Engineering)

    1999-01-01

    Coal fly ash (CFA) produced by power plants in Israel is alkaline and contains aluminium that can be leached by different acids. The mechanism of aluminium leaching from CFA by sulfuric acid was investigated. It was found that higher CFA content, which indicates higher solid to liquid ratio in the leaching suspension, decreases the fraction of aluminium leached by sulfuric acid. This behavior constitutes a new unexplained phenomenon, which could not be explained by analysis of the mass action law of the dissolution reactions, but rather by mass transfer considerations. The leaching process involves a self-inhibition mechanism due to the precipitation of calcium sulfate on the surface and within the CFA particles. The effects of CFA content, acid concentration, temperature, and pre-leaching conditioning, upon leaching rates and yields, were tested.

  7. Relation between silico-aluminous fly ash and its coal of origin

    Institute of Scientific and Technical Information of China (English)

    Jean-Charles Benezet; Pierre Adamiec; Ali Benhassaine

    2008-01-01

    Fly ashes are typical complex solids which incorporate at the same time intrinsic properties derived from the layers (various mineralogical and dimensional spectra) and major transformations generated during prior processing. To use fly ashes in various applications, it is necessary to characterise them completely. The first research to date carried out on silico-aluminous fly ashes in order to characterise them physically,morphologically, chemically and mineralogically, resulted in the recognition that they are relatively simple materials. In the present study, a silico-aluminous fly ash coming from the power station of Albi (France) was selected. Heat treatment at 450 and 1200 ~C together with coal simulated the treatment undergone by coal in the power station in order to mimic real coal residue. In conclusion, the diversity of the particles contained in fly ash could only be explained by the relation existing between the fly ash and its coal of origin.

  8. Trends in the Rare Earth Element Content of U.S.-Based Coal Combustion Fly Ashes.

    Science.gov (United States)

    Taggart, Ross K; Hower, James C; Dwyer, Gary S; Hsu-Kim, Heileen

    2016-06-01

    Rare earth elements (REEs) are critical and strategic materials in the defense, energy, electronics, and automotive industries. The reclamation of REEs from coal combustion fly ash has been proposed as a way to supplement REE mining. However, the typical REE contents in coal fly ash, particularly in the United States, have not been comprehensively documented or compared among the major types of coal feedstocks that determine fly ash composition. The objective of this study was to characterize a broad selection of U.S. fly ashes of varied geological origin in order to rank their potential for REE recovery. The total and nitric acid-extractable REE content for more than 100 ash samples were correlated with characteristics such as the major element content and coal basin to elucidate trends in REE enrichment. Average total REE content (defined as the sum of the lanthanides, yttrium, and scandium) for ashes derived from Appalachian sources was 591 mg kg(-1) and significantly greater than in ashes from Illinois and Powder River basin coals (403 and 337 mg kg(-1), respectively). The fraction of critical REEs (Nd, Eu, Tb, Dy, Y, and Er) in the fly ashes was 34-38% of the total and considerably higher than in conventional ores (typically less than 15%). Powder River Basin ashes had the highest extractable REE content, with 70% of the total REE recovered by heated nitric acid digestion. This is likely due to the higher calcium content of Powder River Basin ashes, which enhances their solubility in nitric acid. Sc, Nd, and Dy were the major contributors to the total REE value in fly ash, based on their contents and recent market prices. Overall, this study shows that coal fly ash production could provide a substantial domestic supply of REEs, but the feasibility of recovery depends on the development of extraction technologies that could be tailored to the major mineral content and origins of the feed coal for the ash. PMID:27228215

  9. Morphological and Strength Properties of Tanjung Bin Coal Ash Mixtures for applied in Geotechnical Engineering Work

    Directory of Open Access Journals (Sweden)

    Abd. Rahim Awang

    2012-01-01

    Full Text Available In Malaysia, coal has been used as a raw material to generate electricity since 1988. In the past, most of the wastage of coal burning especially the bottom ash was not managed properly as it was dumped in the waste pond and accumulated drastically.This paper focuses on some properties of coal ash mixtures (fly  ash and bottom ash mixtures from Tanjung Bin power plant. The characteristics studied were morphological properties, compaction behaviour and strength properties. Strength properties of coal ash mixtures are carried out by conducting direct shear test and unconfined compression test. Besides, morphology and mineralogy of coal ash mixtures are studied using scanning electron microscope (SEM and x-ray diffraction (XRD. The coal ash mixtures were compacted at 95% of maximum dry density, sealed and cured for 0, 14, and 28 days before they were analysed for shear strength, morphological and mineralogical analyses. The shear strength of coal ash mixtures varied depending on the fly ash compositions. The maximum shear strength was obtained at mixture with 50%FA: 50%BA and the value increased with curing periods. The friction angle obtained ranged from 27° to 37°. Morphological analysis showed that the number of irregular shaped particles increased confirming change in material type with curing period. From mineralogical analysis, the crystalline compounds present in Tanjung Bin coal ash were Mullite, Quartz, Calcium Phosphide, Calcite, Cristobalite and Hematite. It can be concluded that the coal ash mixtures can advantageously be applied in the construction of embankments, roads, reclamation and fill behind retaining structures.

  10. Mineralogy and microstructure of sintered lignite coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Marina Ilic; Christopher Cheeseman; Christopher Sollars; Jonathan Knight [Faculty of Technology and Metallurgy, Belgrade (Yugoslavia)

    2003-02-01

    Lignite coal fly ash from the 'Nikola Tesla' power plant in Yugoslavia has been characterised, milled, compacted and sintered to form monolithic ceramic materials. The effect of firing at temperatures between 1130 and 1190{sup o}C on the density, water accessible porosity, mineralogy and microstructure of sintered samples is reported. This class C fly ash has an initial average particle size of 82 {mu}m and contains siliceous glass together with the crystalline phases quartz, anorthite, gehlenite, hematite and mullite. Milling the ash to an average particle size of 5.6 m, compacting and firing at 1170{sup o}C for 1 h produces materials with densities similar to clay-based ceramics that exhibit low water absorption. Sintering reduces the amount of glass, quartz, gehlenite and anhydrite, but increases formation of anorthite, mullite, hematite and cristobalite. SEM confirms the formation of a dense ceramic at 1170{sup o}C and indicates that pyroplastic effects cause pore formation and bloating at 1190{sup o}C. 23 refs., 6 figs., 2 tabs.

  11. JV Task 120 - Coal Ash Resources Research Consortium Research

    Energy Technology Data Exchange (ETDEWEB)

    Debra Pflughoeft-Hassett; Loreal Heebink; David Hassett; Bruce Dockter; Kurt Eylands; Tera Buckley; Erick Zacher

    2009-03-28

    The Coal Ash Resources Research Consortium{reg_sign} (CARRC{reg_sign}, pronounced 'cars') is the core coal combustion product (CCP) research group at the Energy & Environmental Research Center (EERC). CARRC focuses on performing fundamental and applied scientific and engineering research emphasizing the environmentally safe, economical use of CCPs. CARRC member organizations, which include utilities and marketers, are key to developing industry-driven research in the area of CCP utilization and ensuring its successful application. The U.S. Department of Energy is a partner in CARRC through the EERC Jointly Sponsored Research Program, which provides matching funds for industrial member contributions and facilitates an increased level of effort in CARRC. CARRC tasks were designed to provide information on CCP performance, including environmental performance, engineering performance, favorable economics, and improved life cycle of products and projects. CARRC technical research tasks are developed based on member input and prioritization. CARRC special projects are developed with members and nonmembers to provide similar information and to support activities, including the assembly and interpretation of data, support for standards development and technology transfer, and facilitating product development and testing. CARRC activities from 2007 to 2009 included a range of research tasks, with primary work performed in laboratory tasks developed to answer specific questions or evaluate important fundamental properties of CCPs. The tasks were included in four categories: (1) Environmental Evaluations of CCPs; (2) Evaluation of Impacts on CCPs from Emission Controls; (3) Construction and Product-Related Activities; and (4) Technology Transfer and Maintenance Tasks. All tasks are designed to work toward achieving the CARRC overall goal and supporting objectives. The various tasks are coordinated in order to provide broad and useful technical data for CARRC members

  12. Stabilisation of acid generating waste rock with fly ash : immobilization of arsenic under alkaline conditions

    Energy Technology Data Exchange (ETDEWEB)

    Backstrom, M. [Orebro Univ. (Sweden). Man-Technology Environment Research Centre; Sartz, L. [Bergslagen, Kopparberg (Sweden)

    2010-07-01

    This study evaluated the potential for using fly ash as an alkaline material for increasing the pH and decreasing arsenic leaching from highly acidic mine waste. A wood ash sample known to contain high concentrations of both calcium and barium was tested with highly acidic mine waste samples that leached approximately 200 mg/L of arsenic at a liquid/solid ratio of 2. Samples were mixed with the fly ash. Control samples consisted of only mine waste, while the amended samples contained 10 g of mine waste and 10 g of wood ash. Ultra pure water was used as a leachant for both systems until the liquid-solid ratio that corresponded to 900 years of drainage for a waste pile that was 3 m high with an annual run-off of 300 mm. Results of the experimental study showed that the pH in the control increased from 1.7 to 2.7, while the pH in the amended system decreased from 12.6 to 11.5. Initial concentrations of arsenic decreased by almost 3 orders of magnitude in the amended systems. Co-precipitation with the iron, and the calcium arsenate precipitation process were identified as the principal arsenic immobilization mechanisms. The study demonstrated that under the right chemical conditions, alkaline amendments can be used to reduce arsenic leaching from mine wastes. 5 refs., 2 tabs., 1 fig.

  13. Leaching of elements from coal fly ash: Assessment of its potential for use in filling abandoned coal mines

    Energy Technology Data Exchange (ETDEWEB)

    Binay K. Dutta; Swapan Khanra; Durjoy Mallick [Petroleum Institute, Abu Dhabi (UAE)

    2009-07-15

    Leaching of ten elements - namely, Fe, Mn, Ca, Na, K, Cu, Cr, Zn, As and Pb - from four fly ash samples collected from four different coal-fired thermal power plants in West Bengal, India, has been reported. The leaching conditions were selected to broadly simulate that of surface coal mines in order to estimate the usefulness of the materials for back-filling of abandoned mines and to assess the possibility of contamination of the sites by release of heavy metal ions. Sequential batch leaching consisted of four cycles each of seven days duration; the long-term leaching continued over a period of 180 days. The starting pH of the leaching solutions ranged from strongly acidic to strongly basic. The leaching pattern and its dependence on the pH as well as the solid-liquid ratio have been critically analyzed. A much higher mobility of the elements have been expectedly observed at a low pH. Less leaching is found at a high pH except for arsenic. The mobilization pattern is strongly governed by the well-known phenomenon of dissolution and re-precipitation of iron with co-precipitation of a series of elements depending upon the pH of the medium. Extraction equilibrium was reached for Ca, Fe, Na and Zn at certain pH values. A monotonic trend of release for the elements Mn, K, Cu, Pb, Cr and As persisted over the long-term leaching period of 180 days. The alkalinity or the calcium content of an ash sample greatly determines the leaching pattern if the solution pH is neutral or mildly acidic. It appears that the risk pollution of ground water as well as of surface water may not be avoidable if fly ash alone is used for mine back-filling in an environment where acid mine drainage is prominent. Nevertheless blending with lime to enhance the alkalinity appears to offer a practical solution to the problem. 45 refs., 10 figs., 3 tabs.

  14. Radioactivity in coal, ashes and selected wastewaters from Canadian coal-fired steam electric generating stations

    International Nuclear Information System (INIS)

    Coal is known to contain naturally occurring radioactive elements and there has been speculation that as a results, coal-fuelled power generation stations may be significant emitters of these substances. In this report, the subject of radioactivity is introduced. The kinds of radioactive substances which occur naturally in coal formations, the nature of their emissions and the existing information on their behaviour and their effects on environmental organisms are also reviewed. The results of an examination of levels of alpha, beta and gamma radiaton levels, and the substances which produce them in coals, fly ashes, bottom ashes and related wastewaters at six Canadian coal-fuelled power stations are presented. Difficulties in studies of this nature and the potential effects of these releases on organisms in the adjacent aquatic environment are discussed. Existing and potential technologies for the removal of these substances from wastewaters are examined. In general the releases in wastewaters from the six stations were found to be lower than those known to cause short-term or acute biological effects. The potential for long-term effects from such low-level releases could not be accurately assessed because of the paucity of information. A number of recommendations for: improvements in further studies of this nature; the further examination of the fate of naturally occurring radionuclides in the environment; and the determination of the long-term effects of low levels of naturally occurring radioactive substances on aquatic organisms, are made

  15. Preparation, morphology, and thermomechanical properties of coal ash/polyethylene oxide composites

    OpenAIRE

    Saeed, Khalid; Ishaq, Muhammad; Ilyas, Muhammad

    2011-01-01

    Coal ash/polyethylene oxide (ash/PEO) composite films were prepared by the solution casting technique. Scanning electron microscopy (SEM) micrographs indicated that the ash particles were dispersed and embedded well within the polymer matrix. The size of the ash particles in the PEO matrix was less than 3 m m. The polarized optical microscopic (POM) analyses revealed that the pure PEO, upon crystallization, showed distinct crystalline spherulites of a considerable size. The size of...

  16. Natural radioactivity of coal and fly ash at the Nikola Tesla B TPP

    Directory of Open Access Journals (Sweden)

    Kisić Dragica M.

    2013-01-01

    Full Text Available Serbian thermal power plants (TPPs produce siliceous fly ash from lignite in the quantity of approximately 6 million tons per year. The potential market for the use of fly ash is operational, but for the time being, only used by cement producers. Fly ash radioactivity could be one of the major points of concern when larger use of fly ash is planned, particularly in the Serbian construction industry. Radioactivity measurements have been conducted regularly for decades. This paper presents the results of a ten-year fly ash radioactivity measurements at the Nikola Tesla B TPP located in Obrenovac. In addition, the paper compares the natural radionuclides coal content data combusted by the Nikola Tesla B TPP boilers coming from the Kolubara Basin and ash created during coal combustion. Fly ash created in the Nikola Tesla TPPs boilers is characterised by the increased concentration of the natural radionuclides content compared to coal. This is the so-called technologically enhanced natural radioactivity (Technologically Enhanced Occurring Radioactive Material - TENORM of industrial waste, whereas the average specific activities: 232Th in coal amount to 25.2 Bq/kg, and in fly ash and coal 84.2 Bq/kg and 238U 38.3 Bq/kg, respectively. Following the obtained natural radionuclides content results it may be concluded that the Nikola Tesla B TPP ash may be disposed into the environment. Ash may be used also in the construction industry (civil engineering. In building construction applications, ash share as the additive to other building materials depends from its physical and chemical characteristics, as well as from the radionuclides activity: 266Ra, 232Th and 40K. Unlike the thermal power plants regularly (once a year testing the specific natural radionuclides activity in the combusted coal and boiler fly ash, Electric Power Industry of Serbia has not performed large-scale investigations of the natural radionuclides content in coal within the Kolubara

  17. Enrichment and particle size dependence of polonium and other naturally occurring radionuclides in coal ash

    International Nuclear Information System (INIS)

    Coal fired thermal power contributes 70% of power in India. Coal fired power generation results in huge amounts of fly ash and bottom ash of varying properties. Coal, which contains the naturally occurring radionuclides, on burning results in enrichment of these radionuclides in the ashes. In the present study, coal, bottom ash and fly ash samples collected from six coal-fired power plants in India were measured for 210Po using alpha spectrometry and for natural U, 226Ra, 232Th and 40K by an HPGe γ-ray spectrometer. 210Po in fly ash ranged from 25.7 to 70 Bq/kg with a mean value of 40.5 Bq/kg. The range and mean activities of 238U, 226Ra, 232Th, 40K in fly ash were 38.5–101 (78.1), 60–105.7 (79), 20–125 (61.7) and 43.6–200 (100) Bq/kg respectively. Fly ash and bottom ash contains two to five times more natural radionuclides than feed coal. The results were compared with the available data from earlier studies in other countries. The effect of particle size on enrichment factor of the nuclides in fly ash was studied. 210Po showed the largest size dependence with its concentration favoring the smaller particle size while 232Th showed least size dependence. 238U and 226Ra showed behavior intermediate to that of 210Po and 232Th. Also the correlation between sulfur content of the feed coal and activity of 210Po was investigated. Increased sulfur content in feed coal enhanced enrichment of 210Po in ash

  18. Unburned Carbon Loss in Fly Ash of CFB Boilers Burning Hard Coal

    Institute of Scientific and Technical Information of China (English)

    L(U) Junfu(吕俊复); WANG Qimin(王启民); LI Yong(黎永); YUE Guangxi(岳光溪); Yam Y.Lee; Baldur Eliasson; SHEN Jiezhong(沈解忠); YU Long(于龙)

    2003-01-01

    The unburned carbon loss in fly ash of circulating fluidized bed (CFB) boilers, most of which are burning active fuels such as lignite or peat, is normally very low. However, most CFB boilers in China usually burn hard coals such as anthracite and bituminous coal and coal wastes, so the carbon content in the fly ash from these boilers is higher than expected. This paper investigates the source of unburned carbon in the fly ash of CFB boilers burning hard coal through a series of field tests and laboratory investigations. The char behavior during combustion, including fragmentation and deactivation, which is related to the parent coal, has an important impact on the carbon burnout in CFB boilers. The research shows that char deactivation occurs during char burnout in fluidized bed combustion, especially for large particles of low rank coal. The uneven mixing of solids and air in the core region of the furnace also causes poor burnout of carbon in CFB fly ash. An index describing the volatile content (as dry ash free basis) over the heating value is proposed to present the coal rank. The coal combustion efficiency is shown to be strongly connected with this coal index. Several changes in the CFB boiler design are suggested to reduce the unburned carbon loss in the fly ash.

  19. Trace and major element pollution originating from coal ash suspension and transport processes.

    Science.gov (United States)

    Popovic, A; Djordjevic, D; Polic, P

    2001-04-01

    Coal ash obtained by coal combustion in the "Nikola Tesla A" power plant in Obrenovac, near Belgrade, Yugoslavia, is mixed with water of the Sava river and transported to the dump. In order to assess pollution caused by leaching of some minor and major elements during ash transport through the pipeline, two sets of samples (six samples each) were subjected to a modified sequential extraction. The first set consisted of coal ash samples taken immediately after combustion, while the second set was obtained by extraction with river water, imitating the processes that occur in the pipeline. Samples were extracted consecutively with distilled water and a 1 M solution of KCl, pH 7, and the differences in extractability were compared in order to predict potential pollution. Considering concentrations of seven trace elements as well as five major elements in extracts from a total of 12 samples, it can be concluded that lead and cadmium do not present an environmental threat during and immediately after ash transport to the dump. Portions of zinc, nickel and chromium are released during the ash transport, and arsenic and manganese are released continuously. Copper and iron do not present an environmental threat due to element leaching during and immediately after the coal ash suspension and transport. On the contrary, these elements, as well as chromium, become concentrated during coal ash transport. Adsorbed portions of calcium, magnesium and potassium are also leached during coal ash transport. PMID:11341293

  20. Trace and major element pollution originating from coal ash suspension and transport processes.

    Science.gov (United States)

    Popovic, A; Djordjevic, D; Polic, P

    2001-04-01

    Coal ash obtained by coal combustion in the "Nikola Tesla A" power plant in Obrenovac, near Belgrade, Yugoslavia, is mixed with water of the Sava river and transported to the dump. In order to assess pollution caused by leaching of some minor and major elements during ash transport through the pipeline, two sets of samples (six samples each) were subjected to a modified sequential extraction. The first set consisted of coal ash samples taken immediately after combustion, while the second set was obtained by extraction with river water, imitating the processes that occur in the pipeline. Samples were extracted consecutively with distilled water and a 1 M solution of KCl, pH 7, and the differences in extractability were compared in order to predict potential pollution. Considering concentrations of seven trace elements as well as five major elements in extracts from a total of 12 samples, it can be concluded that lead and cadmium do not present an environmental threat during and immediately after ash transport to the dump. Portions of zinc, nickel and chromium are released during the ash transport, and arsenic and manganese are released continuously. Copper and iron do not present an environmental threat due to element leaching during and immediately after the coal ash suspension and transport. On the contrary, these elements, as well as chromium, become concentrated during coal ash transport. Adsorbed portions of calcium, magnesium and potassium are also leached during coal ash transport.

  1. Amenability to dry processing of high ash thermal coal using a pneumatic table

    Institute of Scientific and Technical Information of China (English)

    Dey Shobhana; Gangadhar B.; Gopalkrishna S.J.

    2015-01-01

    High ash thermal coal from India was used to conduct the dry processing of fine coal using a pneumatic table to evolve a techno-economically novel technique. The fine as-received sample having 55.2%ash was subjected to washability studies at variant densities from 1.4 to 2.2 to assess the amenability to separa-tion. The experiments were conducted using a central composite design for assessing the interactive effects of the variable parameters of a pneumatic table on the product yield and ash content. The perfor-mance of the pneumatic table was analyzed in terms of clean coal yield, recovery of combustibles, separation efficiency (Esp) and useful heat value of clean coal. The combustibles of clean coal obtained through a single stage operation at 35% and 38.7% ash were 40% and 63% respectively. However, the two stage processing was more effective in reducing the ash content in the clean coal. The rougher con-centrate generated at higher ash level was subsequently processed in different conditions at 35% ash level, and 58%combustibles could be recovered. Hence, two stage processing increases the combustibles by 18 units and the useful heat value of clean coal increases from 1190 kcal/kg to 3750 kcal/kg.

  2. Measuring reactive pools of Cd, Pb and Zn in coal fly ash from the UK using isotopic dilution assays

    International Nuclear Information System (INIS)

    Highlights: ► Isotope dilution is a useful method to resolve the reactivity of Cd and Pb in ash. ► Only 0.3–3% of the total Pb and Zn and 4–13% of the total Cd in coal ash are labile. ► Fly ash weathering exerts little impact on the lability of Cd, Pb and Zn. ► A 0.05 M EDTA extraction can be used as a simple proxy for isotope dilution assays. - Abstract: Large volumes of coal fly ash are continually being produced and stockpiled around the world and can be a source of environmentally sensitive trace elements. Whilst leaching tests are used for regulatory purposes, these provide little information about the true geochemical behaviour and ‘reactivity’ of trace elements in coal ash because they are poorly selective. Isotope dilution (ID) assays are frequently used in soil geochemistry as a means of measuring the reactive pools of trace metals that are in equilibrium with soil pore waters. This paper examines the applicability of multi-element ID assays in measuring the labile or reactive pool of Cd, Pb and Zn in a range of fresh and weathered fly ash, where pH is generally much more alkaline than in soils. The method generally worked well using 0.0005 M EDTA as a background electrolyte as it provided robust analytical ICP-MS measurements as well as fulfilling the important principle of ID that non-labile metal should not be solubilised. Reactive pools were equivalent to 0.5–3% of the total Pb pool and 4–13% of the total Cd pool. For Zn, where samples had pH < 11.5, the reactive Zn pool varied between 0.3% and 2%; when fresh ash samples with pH > 11.5 were tested, the method failed as the spiked isotope appeared to be sorbed or precipitated. Ash weathering was found to exert little impact on the lability of Cd, Pb and Zn. Isotope dilution results were compared with 0.43 M HNO3 and 0.05 M EDTA extractions, these commonly being used as analogues of the ID assay, and concluded that these can be used as fast, cost-effective and simple proxies for the

  3. Manufacturing of ashless coal by using solvent de-ashing technology

    Energy Technology Data Exchange (ETDEWEB)

    Sang-Do Kim; Kwang-Jae Woo; Soon-Kwan Jeong; Young-Jun Rhim; Si-Huyn Lee [Korea Institute of Energy Research, Daejeon (Republic of Korea). Clean Energy Research Center

    2007-07-01

    Maintenance of a high oil value has an influence to energy crisis and national security in South Korea which does not have energy resources. The coals which have characterized by the abundant reserves and the inexpensive price can be said to be the alternative energy source. Hyper-coal process, which has been developed in Japan since 1999, is a new effective process to produce a clean coal by using the solvent de-ashing technology. When coal is extracted with organic solvent, only the organic portion of coal is dissolved in the solvents. That is possible to apply the low rank coal. This study was performed to produce ashless coal by using the solvent de-ashing technology. The experiment was conducted in the batch(or semi-batch) type reactor with two solvents such as NMP(N-methyl-2-pyrrolidinone) and 1-MN(1-methylnaphthalene) and various coals such as Kideko coal, Roto South coal and Sunhwa coal at 200-400{sup o}C. As a result of the test, extraction yield of coals was more than 60% on daf. Ash concentration which contains the extracted coal was 0.11-1.0wt%. The heat value was increased from 5,400 kcal/kg to 7,920 kcal/kg in the Roto South coal. 10 refs., 4 figs., 2 tabs.

  4. The Future Resources for Eco-building Materials: II.Fly Ash and Coal Waste

    Institute of Scientific and Technical Information of China (English)

    LI Hui; XU Delong

    2009-01-01

    To use fly ash and coal waste effectively,the current technologies for reprocessing and recycling these wastes into eco-building materials were reviewed,such as utilizing fly ash as the component of fly ash cement and low heat cement after the processes of separation,removal of carbon remains and fine comminution,calcining coal waste into kaolin and meta-kaolin with suspension technology,and preparing clinkerless alkali-activated geopolymer materials with fly ash and meta-kaolin.

  5. Assessing the potential of coal ash and bagasse ash as inorganic amendments during composting of municipal solid wastes.

    Science.gov (United States)

    Mohee, Romeela; Boojhawon, Anuksha; Sewhoo, Babita; Rungasamy, Selven; Somaroo, Geeta D; Mudhoo, Ackmez

    2015-08-15

    This study investigates the potential of incorporating inorganic amendments such as coal and bagasse ashes in different composting mixes. 10 different composting mixes were assessed as follows: A-20% bagasse ash (BA) with unsorted municipal solid wastes (UMSW); B-40% BA with UMSW; C-UMSW; D-20% BA with sorted municipal solid wastes (SMSW); E-40% BA with SMSW; F-SMSW; G-20% coal ash (CA) with UMSW; H-40% CA with UMSW; I-20% CA with SMSW and J-40% CA with SMSW. The composting processes were carried out in rotary drum composters. Composting mixes D, F, G and I achieved a temperature above 55 °C for at least 3 days, with the following peak temperatures: D-62 °C, F-57 °C, G-62 °C and I-58 °C. D resulted in the highest average net Volatile solids (VS) degradation of 68.6% and yielded the highest average volume reduction of 66.0%. The final compost from D, G, I, C and F were within range for electrical conductivities (EC) (794-1770 μS/cm) and pH (6.69-7.12). The ashes also helped in maintaining high average water holding capacities within the range of 183-217%. The C/N ratio of sorted wastes was improved by the addition of 20% coal ash and bagasse ash. Higher germination indices, above 0.8 were obtained for the ash-amended compost (D, G, I), indicating the feasibility and enhancement of using bagasse and coal ash as inorganic amendment in the composting process. Regarding heavy metals content, the chromium concentration for the composting mix G was found to be the highest whereas mixes D and I showed compliance with the MS (Mauritian Standards) 164 standards.

  6. Trace and major element pollution originating from coal ash suspension and transport processes

    Energy Technology Data Exchange (ETDEWEB)

    Popovic, A.; Djordjevic, D.; Polic, P. [University of Belgrade, Belgrade (Yugoslavia). Faculty of Science, Dept. of Chemistry

    2001-07-01

    Coal ash obtained from Nikola Tesla A power plant in Obrenovac, near Belgrade, Yugoslavia, is mixed with water of the Sava river and transported to the dump. In order to assess pollution caused by leaching of some minor and major elements during ash transport through the pipeline, two sets of samples (six samples each) were subjected to a modified sequential extraction. The first set consisted of coal ash samples taken immediately after combustion, while the second set was obtained by extraction with river water, imitating the processes that occur in the pipeline. Samples were extracted consecutively with distilled water and a 1 M solution of KCl, pH 7, and the differences in extractability were compared in order to predict potential pollution. It is concluded that lead and cadmium do not present an environmental threat during and immediately after ash transport to the dump. Portions of zinc, nickel and chromium are released during the ash transport, and arsenic and manganese are released continuously. Copper and iron do not present an environmental threat due to element leaching during and immediately after the coal ash suspension and transport. On the contrary, these elements, as well as chromium, become concentrated during coal ash transport. Adsorbed portions of calcium, magnesium and potassium are also leached during coal ash transport.

  7. Polonium and other naturally occurring radionuclides in fly ash from coal fired thermal power plants

    International Nuclear Information System (INIS)

    Coal fired thermal power is the largest contributing power sector in India (about 70%) along with 25 hydel power generation, 3% nuclear power generation and about 1% wind power generation Power on demand by 2012. The role of GIS, GPS and remote sensing in power sector. Published by, CSDMS, IT for geography. The increasing demand of power in a developing country like India has resulted in rapid increase in thermal generation capacity. The coal fired power generation results in huge amounts of fly ash and bottom ash of varying properties. Coal which contains the naturally occurring radionuclides, on burning results in enrichment of these radionuclides in the ashes. In the present study, coal, bottom ash and fly ash samples collected from six coal-fire power plants in India were measured for 210Po using alpha spectrometry and natural U, 226Ra, 232Th and 40K by an HPGeã-ray spectrometer. The results show that fly ash or bottom ash contains two to five times more natural radionuclides than feed coal. The results were compared with the available data from earlier studies in other countries. (author)

  8. Preparation and characterization of carbon-enriched coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Rubio, B.; Izquierdo, M.T.; Mayoral, M.C.; Bona, M.T.; Martinez-Tarazona, R.M. [CSIC, Zaragoza (Spain)

    2008-09-15

    Carbon-enriched fractions have been obtained from two coal fly ash (FA) samples. The FA came from two pulverized-coal fired power stations (Lada and Escucha, Spain) and were collected from baghouse filters. Sieving was used to obtain carbon-enriched fractions, which were further subjected to two beneficiation processes: acid demineralization using HCl and HF, and oil agglomeration using soya oil-water. Yield in weight after sieving, unburned carbon content, and several physicochemical characteristics, of the obtained fractions were used to compare the performance of the beneficiation methods. Low carbon concentration was obtained by sieving. particularly in the case of Escucha FA. However, after acid demineralization or oil agglomeration, fractions containing unburned carbon in a range of 63% to 68% were obtained. These fractions showed differences in mineral phase composition and distribution depending on the FA and oil the beneficiation method used. The textural properties of the obtained fractions varied as a function of their carbon content and the beneficiation method used. However, no significant differences in morphology of the carbonaceous particles were found

  9. Fabrication of Test Tubes for Coal Ash Corrosion Testing

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, R.; Judkins, R.R.; Sikka, V.K.; Swindeman, R.W.; Wright, I.G.

    1999-05-11

    This paper deals with the fabrication of tube sections of four alloys for incorporating into test sections to be assembled by Babcock & Wilcox (B&W) for installation at Ohio Edison Power, Niles Plant. The primary purpose of the installation was to determine the corrosion behavior of ten different alloys for flue gas corrosion. Ohio Edison Power, Niles Plant is burning an Ohio coal containing approximately 3.4% S (dry basis) and approximately 0.4% alkali which causes chronic coal ash corrosion of the unit�s superheater tubing. The 2.5-in.-OD x 0.4in.-wall x 6-in-long sections of four alloys {type 304H coated with Fe3Al alloy FAS [developed at the Oak Ridge National Laboratory (ORNL)], 310 + Ta, modified 800H, and Thermie alloy} were fabricated at ORNL. Each alloy tubing was characterized in terms of chemical analysis and microstructure. The machined tubes of each of the alloys were inspected and shipped on time for incorporation into the test loop fabricated at B&W. Among the alloys fabricated, Thermie was the hardest to extrude and machine.

  10. Elemental characterization of coal ash and its leachates using sequential extraction techniques

    International Nuclear Information System (INIS)

    Over 50 million tons of coal ash are produced annually in North America. Technological improvements in air pollution control have decreased stack emissions but have also increased contaminant concentrations in the ash of coal-fired boiler applications. The leaching of heavy metals and other elements during regulatory tests may cause coal ash to be classified as hazardous waste, complicating land disposal. The hazardous nature of coal ash remains unclear because current toxicity tests fail to effectively characterize the elemental distribution and chemical solubility of trace metals in the landfill environment. Leaching characteristics of ash samples can be investigated with various laboratory extraction procedures in association with multi-elemental analytical techniques (e.g., neutron activation analysis and inductively coupled plasma - atomic emission spectroscopy). Such methods provide more thorough analyses of coal ash leaching dynamics than the regulatory assessments can demonstrate. Regulatory elements including Ag, As, Ba, Cd, Cr, Hg, Pb, and Se were shown to remain in largely insoluble forms while elements such as B and S leached at higher levels. Experimental results may assist operators of coal-fired boiler industries in selecting coal types and disposal options to curtail the leaching of potentially toxic inorganic contaminants. (author) 12 refs.; 4 figs.; 3 tabs

  11. Adsorption of anionic dyes from aqueous solutions onto coal fly ash and zeolite synthesized from coal fly ash

    International Nuclear Information System (INIS)

    Coal fly ash, a waste generated in coal-fired electric power plant, was used to synthesize zeolite by hydrothermal treatment with NaOH solution. The fly ash (CL-2) and this synthesized zeolite (ZM-2) that was characterized as hydroxy-sodalite were used as adsorbents for anionic dyes indigo carmine (IC), and reactive orange 16 (RO16) from aqueous solutions. Effects of contact time, initial dye concentration, pH, adsorbent mass, and temperature were evaluated in the adsorption processes. The kinetics studies indicated that the adsorption followed the pseudo-second order kinetics and that surface adsorption and intraparticle diffusion were involved in the adsorption mechanism. The thermodynamics parameters demonstrated that the adsorption was spontaneous for all adsorption processes. The enthalpy data confirmed the endothermic nature for all adsorption processes except for IC/ZM-2 system which was exothermic. The entropy data showed an increased disorder at the solid/solution interface during the adsorption for all systems except for IC/ZM-2 whose negative entropy value indicated a decreased disorder at the interface. The adsorption isotherms were closely fitted to the Langmuir linear equation. The maximum adsorption capacities were 1.48 mg/g for the IC/CL-2 system; 1.13 mg/g for IC/ZM-2; 0.96 mg/g for RO16/CL-2, and 1.14 mg/g for RO16/ZM-2 at room temperature. The desorption study carried out with water, with acid aqueous solutions, and with an alkali aqueous solution showed to be inefficient both for recovering the dyes and regenerating the adsorbents. (author)

  12. Mercury capture by selected Bulgarian fly ashes: Influence of coal rank and fly ash carbon pore structure on capture efficiency

    Science.gov (United States)

    Kostova, I.J.; Hower, J.C.; Mastalerz, Maria; Vassilev, S.V.

    2011-01-01

    Mercury capture by fly ash C was investigated at five lignite- and subbituminous-coal-burning Bulgarian power plants (Republika, Bobov Dol, Maritza East 2, Maritza East 3, and Sliven). Although the C content of the ashes is low, never exceeding 1.6%, the Hg capture on a unit C basis demonstrates that the low-rank-coal-derived fly ash carbons are more efficient in capturing Hg than fly ash carbons from bituminous-fired power plants. While some low-C and low-Hg fly ashes do not reveal any trends of Hg versus C, the 2nd and, in particular, the 3rd electrostatic precipitator (ESP) rows at the Republika power plant do have sufficient fly ash C range and experience flue gas sufficiently cool to capture measurable amounts of Hg. The Republika 3rd ESP row exhibits an increase in Hg with increasing C, as observed in other power plants, for example, in Kentucky power plants burning Appalachian-sourced bituminous coals. Mercury/C decreases with an increase in fly ash C, suggesting that some of the C is isolated from the flue gas stream and does not contribute to Hg capture. Mercury capture increases with an increase in Brunauer-Emmett-Teller (BET) surface area and micropore surface area. The differences in Hg capture between the Bulgarian plants burning low-rank coal and high volatile bituminous-fed Kentucky power plants suggests that the variations in C forms resulting from the combustion of the different ranks also influence the efficiency of Hg capture. ?? 2010 Elsevier Ltd.

  13. Character of the Si and Al Phases in Coal Gangue and Its Ash

    Institute of Scientific and Technical Information of China (English)

    WANG Lihua; ZHAO Pengda; LI Geng

    2009-01-01

    Analysis of the Si and Al phases in coal gangue fuel and its ash is important for use of coal gangue ashes. A comprehensive study by theoretical and experimental analyses with differential thermal analysis, X-ray diffraction and Infrared Spectroscopy has been made in the present article to explore the diagram of the Si and Al phases in coal gangue fuel and its ashes. It is found that kaolinite and quartz are the main phases in coal gangue fuel. The ratio of moles Al_2O_3 to SiO_2 (i.e., Al_2O_(3(mole))/ SiO_(2(mole)) is usually no more than 0.5 in most coal gangue fuel and its ashes. The kaolinit at about 984°C releases a large quantity of SiO_2, which makes calcine coal gangue more active than coal gangue itself. The relationship between the ratio Al_2O_(3(mole))/SiO_(2(mole))and the components of coal gangue ash is analyzed, resulting in a formula to calculate the quantity of each phase. Applying the formula to the testing samples from an electric plant in north China supports the above conclusions.

  14. Analysis of natural radionuclides in coal, slag and ash in coal-fired power plants in Serbia

    OpenAIRE

    Janković M.M.; Todorović D.J.; Nikolić J.D.

    2011-01-01

    The radioactivity monitoring in the “Nikola Tesla”, “Kolubara”, “Morava” and “Kostolac” coal-fired power plants was performed by the Radiation and Environmental Protection Laboratory, Vinča Institute of nuclear sciences in the period 2003-2010. Monitoring included the analysis of soil, water, flying ash, slag, coal and plants. This paper presents the results of the radioactivity analysis of coal, ash and slag samples. Naturally occurring radionuclides 226Ra, 232Th, 40K, 235U, 238U, and ...

  15. Radium concentration measurements in coal fly ash and cement samples using LR-115 plastic track detectors

    International Nuclear Information System (INIS)

    The increase interest in measuring radium (226Ra) concentration in coal, fly ash and cement is due to its health hazards and environmental pollution. Samples of coal and fly ash from different thermal power stations in northern India were collected and analysed for radium concentration. Cement samples were collected from National Council for Cement and Building Materials (NCB), Ballabgarh (Haryana). The radium concentration is estimated through track etch technique using LR-115 CN detectors. (author)

  16. Pathological and immunological effects of respirable coal fly ash in male Wistar rats

    NARCIS (Netherlands)

    Dormans, J.A.M.A.; Steerenberg, P.A.; Arts, J.H.E.; Bree, L. van; Klerk, A. de; Verlaan, A.P.J.; Bruijntjes, J.P.; Beekhof, P.; Soolingen, D. van; Loveren, H. van

    1999-01-01

    In this study the effects of inhalatory exposure to coal fly ash on lung pathology and the immune system in rats were examined. Rats were exposed to 0, 10, 30, or 100 mg/m3 coal fly ash (6 h/day, 5 days/wk) for 4 wk, or to 0 and 100 mg/m3 for 1 wk, and for 1 wk followed by a recovery in clean air of

  17. Use of Coal Bottom Ash as Mechanical Stabiliser in Subgrade Soil

    OpenAIRE

    Abdus Salaam Cadersa; Akshay Kumar Seeborun; Andre Chan Chim Yuk

    2014-01-01

    This paper presents the laboratory investigation work which forms part of a full scale research road project in Mauritius where coal bottom ash is used as mechanical stabiliser in a saprolitic subgrade soil. Three mixtures of subgrade soil and CBA were investigated in the laboratory, each containing varying percentages of coal bottom ash by weight (15%, 30%, and 40%, resp.). The laboratory research indicated that the mechanical properties of the subgrade soil are improved with the addition of...

  18. Secondary Industrial Minerals from Coal Fly Ash and Aluminium Anodising Waste Solutions

    OpenAIRE

    Nugteren, H.W.

    2010-01-01

    Minerals that are extracted from the earth’s crust to be directly used for their properties are called industrial minerals. This research shows that such minerals can also be produced from industrial residues, hence the name secondary industrial minerals. In this thesis coal fly ash is chosen as one of the industrial residues to work with. Since reuse of coal fly ash is restricted by its technical and environmental quality, the first approach was to improve its quality and thereby extend its ...

  19. Utilization of zeolites synthesized from coal ash for methylene blue removal from water

    OpenAIRE

    Denise Alves Fungaro; Mariza Bruno

    2008-01-01

    The adsorption of methylene blue from aqueous solution was carried out using zeolites synthesized from coal ash as low-cost adsorbents. The coal ash sample was converted to zeolites by hydrothermal treatment using different synthesis parameters. The materials were characterized by physical-chemical analysis, XRD and SEM studies. The adsorption isotherms can be fitted by Freundlich model. The values of the adsorption capacity of adsorbents were similar for adsorbents. Kinetic studies indicate ...

  20. Physicochemical properties and heavy metals leachability of fly ash from coal-fired power plant

    Institute of Scientific and Technical Information of China (English)

    Xiang Wei; Han Baoping; Zhou Dong; Nzihou Ange

    2012-01-01

    The physicochemical properties of fly ash from two kinds of coal-fired power plants were studied.Three aspects were examined:the micro-morphology,the mineral composition and the content of heavy met als.The results show that the fly ash from plants using a circulating fluidized bed are more irregular particles,while the particles from the plants using a pulverized coal-fired boiler are mainly spherical in shape.Quartz and mullite are the main crystalline phases in the ash.Clearly,both the technology and the coal used by a power plant can influence the mineral composition of the ash.The mineral composition of fly ash from a circulating fluidized bed is more complex than that from a pulverized coal-fired boiler.The quantity of elements found in the fly ash is greater than that found in the bottom ash for the same plant.Heavy metals are likely to be enriched in the fly ash.Heavy metal leachability was studied using two leaching methods.The results indicate that most of the heavy metals that leached during either batch leaching or column leaching experiments did not exceed the related maximum concentration standards.But Ni concentrations in the leachates from both batch and column tests exceed the standard.The highest excess rates in both tests were 572% and 497%,which levels might threaten the environment.

  1. Rheology of fly ashes from coal and biomass co-combustion

    DEFF Research Database (Denmark)

    Arvelakis, Stelios; Frandsen, Flemming

    2010-01-01

    The presence of large amounts of alkali metals, chlorine and sulphur in most biomass fuels - compared to coal - can create serious ash-related problems such as deposition, agglomeration and/or corrosion. This paper discusses the viscosity characteristics of fly ash from the co-combustion of vario...... viscosity leading to higher stickiness of the ash particles. Wood co-firing has only minor effects, due to the composition of wood ash and the low percentage of wood in the coal/biomass blend.......The presence of large amounts of alkali metals, chlorine and sulphur in most biomass fuels - compared to coal - can create serious ash-related problems such as deposition, agglomeration and/or corrosion. This paper discusses the viscosity characteristics of fly ash from the co-combustion of various...... coal/biomass blends in a pilot scale pf-boiler. The produced data provide information on the melting of the ash and its flow characteristics, as a function of temperature, which may be used to modify the temperature profile of the boiler in order to avoid slagging. Straw co-firing lowers the ash...

  2. Predicting coal ash fusion temperature based on its chemical composition using ACO-BP neural network

    International Nuclear Information System (INIS)

    Coal ash fusion temperature is important to boiler designers and operators of power plants. Fusion temperature is determined by the chemical composition of coal ash, however, their relationships are not precisely known. A novel neural network, ACO-BP neural network, is used to model coal ash fusion temperature based on its chemical composition. Ant colony optimization (ACO) is an ecological system algorithm, which draws its inspiration from the foraging behavior of real ants. A three-layer network is designed with 10 hidden nodes. The oxide contents consist of the inputs of the network and the fusion temperature is the output. Data on 80 typical Chinese coal ash samples were used for training and testing. Results show that ACO-BP neural network can obtain better performance compared with empirical formulas and BP neural network. The well-trained neural network can be used as a useful tool to predict coal ash fusion temperature according to the oxide contents of the coal ash

  3. Development of bricks with incorporation of coal ash and sludge from water treatment plant

    International Nuclear Information System (INIS)

    Sludge from treatment water Brazilian plant station are, frequently, disposed and launched directly in the water bodies, causing a negative impact in the environment. Also, coal ashes is produced by burning of coal in coal-fired power stations and is the industrial solid waste most generated in southern Brazil: approximately 4 million tons/y. The efficient disposal of coal ashes is an issue due to its massive volume and harmful risks to the environment. The aim of this work was study the feasibility of incorporating these two industrial wastes in a mass used in the manufacture of ecological bricks. Samples of fly ashes from a cyclone filter from a coal-fired power plant located at Figueira County in Parana State, Brazil and waterworks sludge of Terra Preta County in Sao Paulo State, Brazil, were used in the study. Fly ash-sludge and fly ash-sludge-soil-cement bricks were molded and tested, according to the Brazilians Standards. The materials were characterized by physical-chemical analysis, X-ray diffraction, thermal analysis, morphological analysis, Fourier transform infrared spectroscopy and granulometric analysis. The results indicate that the waterworks sludge and coal ashes have potential to be used on manufacturing soil-cement pressed bricks according to the of Brazilians Standards NBR 10836/94. (author)

  4. Study of Enhanced Fine Coal De-sulphurization and De-ashing by Ultrasonic Flotation

    Institute of Scientific and Technical Information of China (English)

    KANG Wen-ze; XUN Hai-xin; CHEN Jun-tao

    2007-01-01

    The feasibility of using ultrasound to enhance the performance of de-sulphurization and de-ashing during slime flotation was investigated. The Setaram C80 calorimeter, the contact angle gauge DCAT21 and an electrophoresis apparatus were used to study the surface nature of coal, pyrite and refuse before and after ultrasonic conditioning. The yield, ash and sulfur contents of equally sized coal slimes were also measured before and after ultrasonic conditioning. The results show that ultrasonic conditioning can drive the separation of pyrite and refuse from coal. After ultrasonic conditioning the hydrophobicity of coal and hydrophilicity of pyrite and refuse increase. The perfect index of flotation, the perfect index of de-sulphurization and the percentage of de-sulphurization increase by 22.51%, 25.36% and 2.49%, respectively. This study shows that ultrasonic conditioning can enhance the performance of de-sulphurization and de-ashing of coal flotation methods.

  5. Research into the automation of the proximate analysis of coal (II): the establishment of a method for the rapid determination of ash in coal, and combustion residues in coal ash

    Energy Technology Data Exchange (ETDEWEB)

    Hase, Y.

    1986-01-01

    The JIS method for coal ash analysis requires 2.5-3 hours for ashing and a total of 3-3.5 hours for the complete determination. The author reports a new method in which ashing time is reduced to about 3 minutes and overall analysis time to approximately 30 minutes. The former is achieved by employing oxygen and using a new type of ashing vessel, while the latter time reduction is due to the introduction of cooling. Measurement precision with the new method is adequate for all practical purposes, apart from in the case of Miike coal, which has a particularly high sulfur content. 2 references, 4 figures, 17 tables.

  6. Triboelectrostatic Separation-an Efficient Method of Producing Low Ash Clean Coal

    Institute of Scientific and Technical Information of China (English)

    章新喜; 边炳鑫; 段超红; 熊建军

    2002-01-01

    At present, coal is mainly consumed as fuel. In fact, coal is also a kind of precious raw material in chemical industry on the premise that some harmful minerals should be removed from coal. The paper presents the results of the research on producing low ash (<2%) coal with triboelectrostatic separator used for producing high-grade active carbon. The test is conducted in bench-scale system, whose capacity is 30~100 kg/h. The results indicate that: 1) the ash content of clean coal increases with the increase of solid content of feedstock, on the contrary, the yield of clean coal is declining; 2) a high velocity may result in a good separation efficiency; 3) for the same solid content, the reunion caused by intermolecular force makes the separation efficiency drop down when the ultra-fine coal is separated; 4) the separation efficiency is improved with the increase of electric field intensity, but there is a good optimized match between the electric field intensity and yield of clean coal; 5) a low rank coal is easy-to-wash in triboelectrostatic separation process; 6) the yield of clean coal can be enhanced and the ash decreased through adapting optimized conditions according to various coals.

  7. Effects of Sediment Containing Coal Ash from the Kingston Ash Release on Embryo-Larval Development in the Fathead Minnow, Pimephales promelas (Rafinesque, 1820)

    Energy Technology Data Exchange (ETDEWEB)

    Greeley Jr, Mark Stephen [ORNL; Elmore, Logan R [ORNL; McCracken, Kitty [ORNL; Sherrard, Rick [Tennessee Valley Authority (TVA)

    2014-01-01

    The largest environmental release of coal ash in U.S. history occurred in December 2008 with the failure of a retention structure at the Tennessee Valley Authority (TVA) Kingston Fossil Plant in East Tennessee. A byproduct of coal-burning power plants, coal ash is enriched in metals and metalloids such as selenium and arsenic with known toxicity to fish including embryonic and larval stages. The effects of contact exposure to sediments containing up to 78 % coal ash from the Kingston spill on the early development of fish embryos and larvae were examined in 7-day laboratory tests with the fathead minnow (Pimephales promelas). No significant effects were observed on hatching success, incidences of gross developmental abnormalities, or embryo-larval survival. Results suggest that direct exposures to sediment containing residual coal ash from the Kingston ash release may not present significant risks to fish eggs and larvae in waterways affected by the spill.

  8. Agglomeration behaviour of high ash Indian coals in fluidized bed gasification pilot plant

    International Nuclear Information System (INIS)

    Although gasification of high ash Indian coals is gaining importance, the resultant uncertainties associated with agglomerate formation are still unresolved. To address this, a suitable pilot scale Fluidized Bed Gasifier was utilized in this study. Stabilized operating conditions in terms of coal feed rate, air feed rate, bed temperature, etc., already identified for maximum possible carbon conversion, were maintained in all experiments and the steam flow rate was only varied. Though the ash fusion temperature of the coals were above 1200 °C, agglomerate was formed during gasification at 950 °C with ‘steam to coal ratio’ less than 0.15 (kg/kg). On increasing this ratio above 0.2 local heat-concentration and agglomeration could be avoided with certainty. Chemical composition alone was not sufficient to explain the relative strength of ash-agglomerates. Compositional variation and state of iron within the matrix were assessed through SEM-EDX and electron paramagnetic resonance (EPR) study, respectively. The probing also required the ash-loading and iron-loading factors to be freshly defined in the context of gasification. Localized heat, large compositional variation, presence of iron in Fe2+ state, ash-loading/iron-loading factors influenced intensity of agglomerate formation. Finally, low temperature agglomerate formation was explained by SiO2–Al2O3–FeO phase diagram. - Highlights: • Pilot plant studies on agglomerate formation during high ash coal gasification. • AFT, chemical analysis of coal ash could not give proper indication. • Ash-/iron-loading factors, compositional variation, Fe2+ leads to agglomeration. • Steam to coal ratio was controlled judiciously to avoid agglomeration. • Cause for agglomeration investigated in depth and remedial adjustment was focused

  9. Radiological significance of coal, slag and fly ash samples from the Eastern Black Sea region

    International Nuclear Information System (INIS)

    This work presents a study of natural radioactivity levels in coal and its combustion residues (fly ash and slag) used in the houses in Black Sea Region, Turkey. Coal, fly ash and slag samples were provided from different locations of the region and analyzed by gamma spectroscopy using a high-purity germanium detector (HPGe). Also, chemical analyses of these samples were carried out using energy dispersive X-ray fluorescence spectrometer. The mean 226Ra activity concentrations in coal, slag and fly ash were measured as 83, 99 and 38 Bq kg-1, respectively. The mean 232Th activity concentrations in coal, slag and fly ash were measured as 108, 113 and 50 Bq kg-1, respectively. The mean 40K activity concentrations in coal, slag and fly ash were found to be 366, 381 and 204 Bq kg-1, respectively. The potential radiological hazards associated to these materials were evaluated by calculating the radium equivalent activity (Raeq), the air absorbed gamma dose rate (D), the annual effective dose rate (AED), the external hazard index (Hex) and internal hazard index (Hin) and compared with the internationally accepted or reference values. The mean Raeq values of the coal, fly ash and slag samples were lower than the recommended maximum values 370 Bq kg-1 by the Organization for Economic Cooperation and Development (OECD). The overall mean outdoor terrestrial gamma air absorbed dose rate in coal, fly ash and slag samples are 119, 129 and 62 nGy h-1 and the corresponding outdoor annual effective doses are 0.60, 0.32 and 0.64 mSv y-1, which is higher than the worldwide average (0.07 mSv y-1), respectively. Moreover, the enrichment factors relative to the input coal are calculated for the radionuclide contents observed. Calculated enrichment factor values for 226Ra and 232Th were found 1.14 and 1.01, respectively. (orig.)

  10. Genesis of some tertiary Indian coals from the chemical composition of ash - a statistical approach: Part 1

    Science.gov (United States)

    Sharma, Arpita; Saikia, Ananya; Khare, Puja; Baruah, B. P.

    2014-10-01

    In the present investigation, 37 numbers of high sulphur tertiary coal samples from Meghalaya, India have been studied on the basis of proximate and ash analysis. Various statistical tools like Bivariant Analysis, Principal Component Analysis (PCA) and Hierarchical Clustering Analysis (HCA), and also the geochemical indicators were applied to determine the dominant detrital or authigenic affinity of the ash forming elements in these coals. The genetic interpretation of coal as well as the coal ash has been carried out based on chemical compositions of high temperature ash (HTA) by using Detrital/Authigenic Index. X-Ray Diffraction (XRD) analysis was also carried out to study the mineralogy of the studied coal ashes. Both statistical tools and geochemical indicators have confirmed the detrital nature of these coals as well as the ash forming elements.

  11. Genesis of some tertiary Indian coals from the chemical composition of ash – a statistical approach: Part 1

    Indian Academy of Sciences (India)

    Arpita Sharma; Ananya Saikia; Puja Khare; B P Baruah

    2014-10-01

    In the present investigation, 37 numbers of high sulphur tertiary coal samples from Meghalaya, India have been studied on the basis of proximate and ash analysis. Various statistical tools like Bivariant Analysis, Principal Component Analysis (PCA) and Hierarchical Clustering Analysis (HCA), and also the geochemical indicators were applied to determine the dominant detrital or authigenic affinity of the ash forming elements in these coals. The genetic interpretation of coal as well as the coal ash has been carried out based on chemical compositions of high temperature ash (HTA) by using Detrital/Authigenic Index. X-Ray Diffraction (XRD) analysis was also carried out to study the mineralogy of the studied coal ashes. Both statistical tools and geochemical indicators have confirmed the detrital nature of these coals as well as the ash forming elements.

  12. Production of low ash coal by thermal extraction with N-methyl-2-pyrrolidinone

    Energy Technology Data Exchange (ETDEWEB)

    Do Kim, S.; Woo, K.J.; Jeong, S.K.; Rhim, Y.J.; Lee, S.H. [Korean Institute for Energy Research, Taejon (Republic of Korea). Clean Coal Technological Research Center

    2008-07-15

    Present study was conducted for the purpose of producing low ash coal from LRC (low rank coals) such as lignite and sub-bituminous coal through thermal extraction using polar solvent. Extraction from bituminous coal was also investigated for comparison. NMP as a polar solvent was used. The ratio of coal to solvent was adjusted as 1:10. Experimental conditions were established which include the extraction temperature of 200-430{sup o}C, initial applied pressure of 1-20 bar and extraction time of 0.5-2 hr were used. Extraction yield and ash content of extracted and residual coal were measured. The extraction yield increased with the increase of extraction temperature, and the ash content of extracted coal decreased below 0.4% at 400{sup o}C from the raw coal samples that have the ash contents of 4-6%. According to the analysis of experiments results, fixed carbon and calorific value increased, and H/C and O/C decreased.

  13. Study on Thermal Insulation Zeolite by Coal Fly Ash

    Directory of Open Access Journals (Sweden)

    Huiping Song

    2014-01-01

    Full Text Available This paper takes the coal fly ash as the material and makes zeolite with low thermal conductivity under a two-step synthesis for the purpose of thermal insulation. It studies main factors affecting zeolite such as the different concentration of NaOH, the solid-liquid ratio, the silica-alumina ratio, and the crystallization temperature. The optimal conditions were obtained that the NaOH concentration was 3 mol/L, the solid-liquid ratio was 10 : 1, the silica-alumina ratio was 2, and the crystallization temperature was 12°C. Zeolites have multiple pores and skeletal structures under SEM observation. The mean particle size was 2.78 um of concentrated distribution. The pore volume was 0.148 m3/g measured by BET analysis, the specific surface was 118.6 m2/g, and the thermal conductivity was 0.153 W/(m·K. Zeolite was proved to be a qualified insulation material which can be used in thermal insulation coating as a new material of energy conservation.

  14. Synthesis of merlinoite from Chinese coal fly ashes and its potential utilization as slow release K-fertilizer

    OpenAIRE

    Li, Jing; Zhuang, Xinguo; Font, Oriol; Moreno, Natalia; Vallejo, V. Ramón; Querol, Xavier; Tobias, Aurelio

    2014-01-01

    This study focuses on the synthesis of merlinoite from Chinese coal fly ashes by KOH direct conversion method, with special emphasis on the application of synthetic merlinoite as fertilizer. These fly ashes were collected from two pulverized-coal combustion (PCC) power plants in Xinjiang, Northwest China. The synthesis results are influenced by fly ash characteristics and different synthesis conditions (KOH solution concentrations, activation temperature, time, and KOH/fly ash ratios). A high...

  15. Utilization of fly ash from coal-fired power plants in China

    Institute of Scientific and Technical Information of China (English)

    Da-zuo CAO; Eva SELIC; Jan-Dirk HERBELL

    2008-01-01

    The rapidly increasing demand for energy in China leads to the construction of new power plants all over the country. Coal, as the main fuel resource of those power plants, results in increasing problems with the disposal of solid residues from combustion and off gas cleaning. This investigation describes chances for the utilization of fly ash from coal-fired power plants in China. After briefly comparing the situation in China and Germany, the status of aluminum recycling from fly ash and the advantages for using fly ash in concrete products are introduced. Chemical and physical analyses of Chinese fly ash samples, e.g., X-ray diffraction (XRD), ICP (Inductive Coupled Plasma) and particle size analysis, water requirement, etc. are presented. Reasonable amounts of aluminum were detected in the samples under investigation, but for recovery only sophisticated procedures are available up to now. Therefore, simpler techniques are suggested for the first steps in the utilization of Chinese fly ash.

  16. On Mattering: A Coal Ash Flood and the Limits of Environmental Knowledge

    Directory of Open Access Journals (Sweden)

    Hatmaker, Susie

    2014-05-01

    Full Text Available This paper investigates the largest flood of coal ash in United States history as an event at once monumental and insignificant. It traces affective forces generative of both the ash, and its invisibility. In the moment of rupture, the ash flowed out of a large holding pond in a spill of layered sediments – each layer of particulate a temporary resting place for a forceful trajectory of matter spurned into motion elsewhere in space and time. This paper takes up the atemporal matter of this coal ash flood to ask: out of what movements and connections was the ash formed? How did this particular landscape change to accommodate its accumulation? What trajectories flowed into the pond, and what hidden memories sat buried in its mass? Drawing on ethnographic and archival research, this paper weaves together juxtaposed scenes that form (some of the backstory of this event, and invites a reconsideration of the practices of knowledge that helped condition it.

  17. Radiochemical tecniques applied to laboratory studies of water leaching of heavy metals from coal fly ash

    International Nuclear Information System (INIS)

    Assessment of the potential environmental impact of heavy metals (HM) mobilized by coal-fired plants showed that water leaching of HM from pulverized fuel ash may for certain HM constitute an important pathway to the aquatic environment. This process was therefore investigated in more detail by laboratory experiments. Batch experiments were performed in order to simulate ash pond conditions, whereas column experiments were carried out to represent water leaching from fly ash deposits. Using highly sensitive radiochemical techniques such as radioactive tracers and neutron activation of fly ash the fate of a single HM could be easily followed even in very low concentration experiments. Employing radioisotopic tracers the distribution coefficients of simple ionic forms of As, Sb, Bi, Se, Te, Cr, Mo, W, Ni, Cd in a coal fly ash/water system could be determined as a function of pH. Results obtained on the absorption and desorption behaviour of HM on coal fly ash can be explained in part on the basis of the surface predominance and the aqueous chemistry of single ionic, mainly anionic, forms of the relative elements. But ion exchange and coprecipitation phenomena also seem to be important processes. The nature and concentration of ions contained originally in the water used (distilled water, fly ash leachate and seawater) were found to have a strong influence on the sorptive behaviour of HM on coal ashes. The high degree of applicability of radiochemical and nuclear techniques to coal ash water leaching problems has been demonstrated and further points for subsequent research in this field possibly using nuclear techniques are indicated. (author)

  18. Natural radioactive level in coal and ash and building material products from coal-fired power plants in Beijing

    International Nuclear Information System (INIS)

    The authors report the methods and results of survey on content of 226Ra, 232Th and 40K in samples of coal, ash from 5 coal-fired power plants in Beijing and ash bricks, air-added concrete from Beijing air-added concrete plant from February to December, 1993. 55 coal Samples, 26 ash Samples, 8 ash brick samples and 8 air-added concrete samples were collected. These samples were analysed by type FH-1936 low background γ-spectrometer. The average value of 226Ra, 232Th and 40K of coal is 28.9, 35.9 and 80.4 Bq/kg, respectively; 101, 110 and 347 Bq/kg, for ash; 47.6, 72.9 and 288 Bq/kg, for ash brick and 47.8, 70.1 and 216 Bq/kg for air-added concrete, respectively. In addition, γ radiation dose rate inside buildings of workers, dwelling houses of the Beijing air-added concrete plant made of ash building materials were investigated and analysed. The range and the average value of 8 measurement values is (67.4-84.7) nGy/h and 78.2 nGy/h, respectively. It approaches to the average value inside bungalow of bricks and a building of two or more storeys made of bricks and concrete in Beijing and within normal range. The results show that it might not cause obviously increase of γ radiation dose rate inside building when the ash were rationally used as the raw materials of building

  19. Characterization of bottom ashes from coal pulverized power plants to determine their potential use feasibility

    Energy Technology Data Exchange (ETDEWEB)

    Menendez, E.; Alvaro, A. M.; Argiz, C.; Parra, J. L.; Moragues, A.

    2013-07-01

    The disposal of coal by products represents environmental and economical problems around the world. Therefore, the reuse and valorisation of this waste has become an important issue in the last decades. While high-value construction products containing fly ash were developed and its use is actually totally accepted as an addition to cement, the use of the bottom ash as supplementary cementitious material has not been allow. This paper examines the chemical and physical properties of fly ashes and bottom ashes from two different coal power plants in order to compare them and analyse the potential feasibility of bottom ash as cement replacement. The mechanical properties of cement mortars made with different percentages of both ashes were also study. The results obtained showed similar chemical composition of both kinds of ashes. The compressive strength values of mortars with 10 % and 25 % of cement replacement (at 28 days) were above the limits established in European standards and there were not significant differences between fly ash and bottom ash from both origins. (Author)

  20. Nano-mineralogical investigation of coal and fly ashes from coal-based captive power plant (India): an introduction of occupational health hazards

    OpenAIRE

    Oliveira, Marcos L.S.; Waanders, Frans B.; Marostega, Fabiane; Taffarel, Silvio R.; Saikia, Binoy K.

    2014-01-01

    Coal derived nano-particles has been received much concern recently around the world for their adverse effects on human health and the environment during their utilization. In this investigation the mineral matter present in some industrially important Indian coals and their ash samples are addressed. Coal and fly ash samples from the coal-based captive power plant in Meghalaya (India) were collected for different characterization and nano-mineralogy studies. An integrated application of adva...

  1. Full-scale ash deposition measurements at Avedøre Power Plant unit 2 during suspension-firing of wood with and without coal ash addition

    DEFF Research Database (Denmark)

    Wu, Hao; Shafique Bashir, Muhammad; Jensen, Peter Arendt

    along with the fly ash and bottom ash from the plant were characterized extensively by SEM-EDS, ICP-OES/IC and XRD. Based on the results from the present work, the deposit formation and shedding mechanisms under different operational conditions were proposed and discussed. The influence of coal ash......The formation of deposits during suspension-firing of wood at Avedøre Power Plant unit 2 (AVV2) was studied by using an advanced deposit probe system. The tests were conducted both with and without coal ash addition, and at two different locations with flue gas temperatures of 1250-1300 oC and 750...... addition on deposit formation during wood suspension-firing at AVV2 was evaluated. It was revealed that the addition of coal fly ash could significantly influence the ash deposition/shedding behaviors and the deposit properties. The effect was evident at both measurement locations. At the location...

  2. Suspension-firing of wood with coal ash addition: Probe measurements of ash deposit build-up at Avedøre Power Plant (AVV2)

    DEFF Research Database (Denmark)

    Shafique Bashir, Muhammad; Jensen, Peter Arendt; Jappe Frandsen, Flemming;

    This report is about full-scale probe measurements of deposit build-up and removal conducted at the Avedøreværket Unit 2, a 800 MWth suspension boiler, firing wood and natural gas with the addition of coal ash. Coal ash was used as an additive to capture potassium (K) from wood-firing. Investigat......This report is about full-scale probe measurements of deposit build-up and removal conducted at the Avedøreværket Unit 2, a 800 MWth suspension boiler, firing wood and natural gas with the addition of coal ash. Coal ash was used as an additive to capture potassium (K) from wood......-firing. Investigations of deposit formation rate were made by use of an advanced online ash deposition/shedding probe. Quantification of ash deposition and shedding was made via deposit mass uptake signals obtained from the deposit probe. The influence of coal ash, flue gas temperature, probe surface temperature...... oC), deposit removal through surface melting was not identified. SEM-EDS analysis of the deposits showed significant presence of Ca, Al and Si, indicating that a significant amount of K has been captured by coal ash to form deposits rich in calcium-aluminum-silicates, and possible release of Cl...

  3. Use of Coal Bottom Ash as Mechanical Stabiliser in Subgrade Soil

    Directory of Open Access Journals (Sweden)

    Abdus Salaam Cadersa

    2014-01-01

    Full Text Available This paper presents the laboratory investigation work which forms part of a full scale research road project in Mauritius where coal bottom ash is used as mechanical stabiliser in a saprolitic subgrade soil. Three mixtures of subgrade soil and CBA were investigated in the laboratory, each containing varying percentages of coal bottom ash by weight (15%, 30%, and 40%, resp.. The laboratory research indicated that the mechanical properties of the subgrade soil are improved with the addition of bottom ash. Highest values for soaked and unsoaked CBR values were obtained for the mixture containing 30% by weight of bottom ash, which were 145% and 95%, respectively, as compared to 40% and 55% for the subgrade soil alone. Upon addition of coal bottom ash, a considerable decrease in swelling potential during soaking was observed for the mixture containing 40% by weight of CBA. The swell decreased from 0.17% for the subgrade soil alone to 0.04% for the mixture containing 40% by weight of CBA. Moreover, a CBA content of 30% resulted in a mix of intermediate plasticity as compared to the subgrade soil which is highly plastic. It is concluded that coal bottom ash can be used successfully as a mechanical stabilizer in the experimental subgrade soil by addition of 30 to 40% of CBA.

  4. Mercury in coals and fly ashes from Republika and Bobov dol thermoelectric power plants

    Science.gov (United States)

    Kostova, I.; Vassileva, C.; Hower, J.; Mastalerz, Maria; Vassilev, S.; Nikolova, N.

    2011-01-01

    Feed coal and y ash samples were collected at Republika and Bobov Dol thermoelectric power plants (TPPs). The y ashes (FAs) were collected fromthree rows of the hot-side electrostatic precipitators (ESPs) array. Each sam- ple was wet-screened at 100, 200, 325 and 500 mesh. The coals and y ashes were characterized with regard to their petrological and chemical composition (including mercury content) and to their surface area properties. The calculated enrichment factor (EF) shows that the Hg concentrations in the bulk coal samples from Republika and Bobov Dol TPPs are 2.19 and 1.41, respectively. In some coal size fractions the EF can be up to 4 times higher than the Clarke value. The calculated EF for fly ashes shows that the Hg concentrations in the bulk samples studied are lower (between 0.03 and 0.32) than the Clarke value. The most enriched in Hg are the fly ashes from the 3rd ESP row of Republika TPP. The Hg distribution in bulk FAs taken from dierent rows of the electrostatic precipitators of both TPPs studied shows well established tendency of gradual increase in the Hg content from the 1st to the 2nd and 3rd ESP rows. The correlation between Hg content and surface area, mesopore and micropore volume of y ashes was also done in the present investigation.

  5. Remediação de drenagem ácida de mina usando zeólitas sintetizadas a partir de cinzas leves de carvão Remediation of acid mine drainage using zeolites synthesized from coal fly ash

    Directory of Open Access Journals (Sweden)

    Denise Alves Fungaro

    2006-07-01

    Full Text Available Zeolitic material was synthesized from coal fly ashes (baghouse filter fly ash and cyclone filter fly ash by hydrothermal alkaline activation. The potential application of the zeolitic product for decontamination of waters from acid mine drainage was evaluated. The results showed that a dose of 30 g L-1 of zeolitic material allowed the water to reach acceptable quality levels after treatment. Both precipitation and cation-exchange processes accounted for the reduction in the pollutant concentration in the treated waters.

  6. Geochemistry of ultra-fine and nano-compounds in coal gasification ashes: A synoptic view

    Energy Technology Data Exchange (ETDEWEB)

    Kronbauer, Marcio A. [Centro Universitário La Salle, Mestrado em Avaliação de Impactos Ambientais em Mineração, Victor Barreto, 2288 Centro, 92010-000 Canoas, RS (Brazil); Universidade Federal do Rio Grande do Sul, Escola de Engenharia, Departamento de Metalurgia, Centro de Tecnologia, Av. Bento Gonçalves, 9500, Bairro Agronomia, CEP: 91501-970, Porto Alegre, RS (Brazil); Izquierdo, Maria [School of Applied Sciences, Cranfield University, Bedfordshire MK43 0AL (United Kingdom); Dai, Shifeng [State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Beijing 100083 (China); Waanders, Frans B. [School of Chemical and Minerals Engineering, North West University (Potchefstroom campus), Potchefstroom 2531 (South Africa); Wagner, Nicola J. [School of Chemical and Metallurgical Engineering, University of the Witwatersrand, Johannesburg (South Africa); Mastalerz, Maria [Indiana Geological Survey, Indiana University, Bloomington, IN 47405-2208 (United States); Hower, James C. [University of Kentucky Center for Applied Energy Research, 2540 Research Park Drive, Lexington, KY 40511 (United States); Oliveira, Marcos L.S. [Environmental Science and Nanotechnology Department, Catarinense Institute of Environmental Research and Human Development, IPADHC, Capivari de Baixo, Santa Catarina (Brazil); Taffarel, Silvio R.; Bizani, Delmar [Centro Universitário La Salle, Mestrado em Avaliação de Impactos Ambientais em Mineração, Victor Barreto, 2288 Centro, 92010-000 Canoas, RS (Brazil); and others

    2013-07-01

    The nano-mineralogy, petrology, and chemistry of coal gasification products have not been studied as extensively as the products of the more widely used pulverized-coal combustion. The solid residues from the gasification of a low- to medium-sulfur, inertinite-rich, volatile A bituminous coal, and a high sulfur, vitrinite-rich, volatile C bituminous coal were investigated. Multifaceted chemical characterization by XRD, Raman spectroscopy, petrology, FE-SEM/EDS, and HR-TEM/SEAD/FFT/EDS provided an in-depth understanding of coal gasification ash-forming processes. The petrology of the residues generally reflected the rank and maceral composition of the feed coals, with the higher rank, high-inertinite coal having anisotropic carbons and inertinite in the residue, and the lower rank coal-derived residue containing isotropic carbons. The feed coal chemistry determines the mineralogy of the non-glass, non-carbon portions of the residues, with the proportions of CaCO{sub 3} versus Al{sub 2}O{sub 3} determining the tendency towards the neoformation of anorthite versus mullite, respectively. Electron beam studies showed the presence of a number of potentially hazardous elements in nanoparticles. Some of the neoformed ultra-fine/nano-minerals found in the coal ashes are the same as those commonly associated with oxidation/transformation of sulfides and sulfates. - Highlights: • Coal waste geochemisty can provide increased environmental information in coal-mining areas. • Oxidation is the major process for mineral transformation in coal ashes. • The electron bean methodology has been applied to investigate neoformed minerals.

  7. DEVELOPMENT OF X-RAY FLUORESCENCE TECHNIQUE FOR THE URANIUM DETERMINATION IN MONGOLIAN COAL, COAL ASH, AND PHOSPHATE ORE

    OpenAIRE

    Cherkashina, Tat`iana Yur`evna; Bolortuya, Damdinsuren; Revenko, Anatolii Grigor`evich; Zuzaan, Purev

    2014-01-01

    The results of the determination of uranium in Mongolian brown coal, coal ash, phosphate rock, and technological samples by X-ray fluorescence (XRF) spectrometry are presented. Technological samples were produced from phosphates by chemical treatment. Powder geological samples and Certified Reference Materials (CRMs) were pressed as tablets. For chosen conditions of the sample preparation procedure analytical figures of merit were carefully studied, as exemplified by the rock and uranium ore ...

  8. Preliminary report on coal pile, coal pile runoff basins, and ash basins at the Savannah River Site: effects on groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, E. [Westinghouse Savannah River Company, AIKEN, SC (United States)

    1997-04-28

    Coal storage piles, their associated coal pile runoff basins and ash basins could potentially have adverse environmental impacts, especially on groundwater. This report presents and summarizes SRS groundwater and soil data that have been compiled. Also, a result of research conducted on the subject topics, discussions from noted experts in the field are cited. Recommendations are made for additional monitor wells to be installed and site assessments to be conducted.

  9. Evidence for Coal Ash Ponds Leaking in the Southeastern United States.

    Science.gov (United States)

    Harkness, Jennifer S; Sulkin, Barry; Vengosh, Avner

    2016-06-21

    Coal combustion residuals (CCRs), the largest industrial waste in the United States, are mainly stored in surface impoundments and landfills. Here, we examine the geochemistry of seeps and surface water from seven sites and shallow groundwater from 15 sites in five states (Tennessee, Kentucky, Georgia, Virginia, and North Carolina) to evaluate possible leaking from coal ash ponds. The assessment for groundwater impacts at the 14 sites in North Carolina was based on state-archived monitoring well data. Boron and strontium exceeded background values of 100 and 150 μg/L, respectively, at all sites, and the high concentrations were associated with low δ(11)B (-9‰ to +8‰) and radiogenic (87)Sr/(86)Sr (0.7070 to 0.7120) isotopic fingerprints that are characteristic of coal ash at all but one site. Concentrations of CCR contaminants, including SO4, Ca, Mn, Fe, Se, As, Mo, and V above background levels, were also identified at all sites, but contamination levels above drinking water and ecological standards were observed in 10 out of 24 samples of impacted surface water. Out of 165 monitoring wells, 65 were impacted with high B levels and 49 had high CCR-contaminant levels. Distinct isotope fingerprints, combined with elevated levels of CCR tracers, provide strong evidence for the leaking of coal ash ponds to adjacent surface water and shallow groundwater. Given the large number of coal ash impoundments throughout the United States, the systematic evidence for leaking of coal ash ponds shown in this study highlights potential environmental risks from unlined coal ash ponds. PMID:27286270

  10. The desulfurization behavior of mineral matter in ash during coal combustion at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Tian-hua; Li, Run-dong; Li, Yan-ji; Zhou, Jun-huz; Cen, Ke-fa [Shenyang Institute of Aeronautical Engineering, Shenyang (China)

    2007-02-15

    In allusion to the desulfurization characteristic of coal ash, the desulfurization of the ash and CaO, Al{sub 2}O{sub 3} added to Changguang coal with different proportions at high temperature was studied. Sulphoaluminate as the main desulfurization product was analyzed by X-ray diffraction and SEM visualization. Experimental results indicate that higher proportion of ash added can improve the desulfurization efficiency. The sulphoaluminate content in residue increases with increasing the addition of ash. The desulfurization efficiency of the additive CaO and Al{sub 2}O{sub 3} is up to 24% at 1300{sup o}C, at the same time the sulphoaluminate is detected in the residue. 6 refs., 10 figs., 2 tabs.

  11. Trophic structure and metal bioaccumulation differences in multiple fish species exposed to coal ash-associated metals

    Energy Technology Data Exchange (ETDEWEB)

    Otter, Ryan [Middle Tennessee State University; Bailey, Frank [Middle Tennessee State University; Fortner, Allison M [ORNL; Adams, Marshall [ORNL

    2012-01-01

    On December 22, 2008 a dike containing coal fly ash from the Tennessee Valley Authority Kingston Fossil Plant near Kingston Tennessee USA failed and resulted in the largest coal ash spill in U.S. history. Coal ash, the by-product of coal combustion, is known to contain multiple contaminants of concern, including arsenic and selenium. The purpose of this study was to investigate the bioaccumulation of arsenic and selenium and to identify possible differences in trophic dynamics in feral fish at various sites in the vicinity of the Kingston coal ash spill. Elevated levels of arsenic and selenium were observed in various tissues of largemouth bass, white crappie, bluegill and redear sunfish from sites associated with the Kingston coal ash spill. Highest concentrations of selenium were found in redear sunfish with liver concentrations as high as 24.83 mg/kg dry weight and ovary concentrations up to 10.40 mg/kg dry weight at coal ash-associated sites. To help explain the elevated selenium levels observed in redear sunfish, investigations into the gut pH and trophic dynamics of redear sunfish and bluegill were conducted which demonstrated a large difference in the gut physiology between these two species. Redear sunfish stomach and intestinal pH was found to be 1.1 and 0.16 pH units higher than in bluegill, respectively. In addition, fish from coal ash-associated sites showed enrichment of 15N & 13C compared to no ash sites, indicating differences in food web dynamics between sites. These results imply the incorporation of coal ash-associated compounds into local food webs and/or a shift in diet at ash sites compared to the no ash reference sites. Based on these results, further investigation into a broader food web at ash-associated sites is warranted.

  12. Sorption and chemical transformation of PAHs on coal fly ash. Technical progress report No. 1, [October--December 1991

    Energy Technology Data Exchange (ETDEWEB)

    Mamantov, G.; Wehry, E.L.

    1991-12-31

    The objective of this research is to characterize the interactions of coal fly ash with polycyclic aromatic hydrocarbons (PAHs) and their derivatives, and to understand the influence of the surface properties of coal ash (and other atmospheric particles) on the chemical transformations of polycyclic aromatic compounds. Studies to be carried out in this project include: (1) Fractionation of heterogeneous coal fly ash samples into different particle types varying in size and chemical composition (carbonaceous, mineral-magnetic, and mineral nonmagnetic); (2) Measurement of the rates of chemical transformation of PAHs and PAH derivatives (especially nitro-PAHs) and the manner in which the rates of such processes are influenced by the chemical and physical properties of coal fly ash particles; (3) Chromatographic and spectroscopic studies of the nature of the interactions of coal fly ash particles with PAHs and PAH derivatives; (4) Characterization of the fractal nature of fly ash particles (via surface area measurements) and the relationships of ``surface roughness`` of fly ash particles to the chemical behavior of PAHs sorbed on coal ash particles; (5) Identification of the major products of chemical transformation of PAHs on coal ash particles, and examination of any effects that may exist of the nature of the coal ash surface on the identities of PAH transformation products; and (6) Studies of the influence of other sorbed species on the chemical behavior of PAHs and PAH derivatives on fly ash surfaces. PAHs are deposited, under controlled laboratory conditions, onto coal ash surfaces from the vapor phase, in order to mimic the processes by which PAHs are deposited onto particulate matter in the atmosphere.

  13. Screening coal combustion fly ashes for application in geopolymers

    NARCIS (Netherlands)

    Valcke, S.L.A.; Pipilikaki, P.; Sarabér, A.J.; Fischer, H.R.; Nugteren, H.W.

    2013-01-01

    Driven by cost and sustainability, secondary resource materials such as fly ash, blast furnace slag, and bottom ash are increasingly used for alternative types of concrete binders, such as geopolymers. Because secondary resources may be highly variable from the perspective of geopolymers, it is ofte

  14. The U.S. power industry's activities to expand coal ash utilization in face of lower ash quality

    Energy Technology Data Exchange (ETDEWEB)

    Golden, D.M. [Electric Power Research Inst., Palo Alto, CA (United States)

    2001-07-01

    The use of coal by electric power utilities results in more than 105 million tons of by products each year in the United States. More restrictive air quality emission limits have resulted in cleaner air, but this means the fly ash is more contaminated and cannot be used in its largest market, the concrete industry. For this reason, the Electric Power Research Institute (EPRI) conducted a 5 year program at increasing ash utilization in the cement and concrete market in the United States. This initiative was in response to recent concerns regarding the impacts on ash quality due to more aggressive nitrogen oxide (NOx) controls. The EPRI program provides the technical basis for protecting the bulk sale of coal ash in high-volume applications in cement and concrete and other high volume civil engineering applications. Fly ash derived from NOx control systems has higher carbon levels and ammonia levels. Problems with ammoniated ash are a major concern for coal-fired power plants. It was shown that there are four ways to minimize the impact of NOx controls that reduce ash quality directly affecting ash utilization. These are: (1) prevention of carbon accumulation in fly ash for use in sensitive markets, (2) carbon removal, (3) concentration of reactive ash fractions by removal of coarse fractions, and (4) ammonia removal. It was concluded that more studies are needed to examine long-term durability and other properties before any of these options can be exploited on an industrial scale. 21 refs., 1 tab.

  15. Thermal properties of insulating material prepared from coal fly ash and asphalt

    International Nuclear Information System (INIS)

    Coal power plants are producing ash in enormous quantity as fly ash and bottom ash, whenever coal is combusted. Lakhra Coal Power Plant produces waste of solid fossil fuel and lime stone. Due to the silica, alumina and iron oxide it is good to be used in cement preparation and land filling. In this study a new application is identified, which is more useful and beneficial. This paper presents the results carried out investigating the insulating material prepared from the coal fly ash and asphalt by using the simple unit operations of sizing the materials. At melting temperature of the asphalt sieved fly ash is mixed with it to produce complex heavy sludge. Two samples of different ratios from the rapidly solidifying insulating material were prepared in the molding press at 200 psi pressure. Arm-field heat conduction apparatus HT-l was applied to test its thermal properties. Thermal properties of the material were observed to be heat resistant with mean thermal conductivity at 10 watt 0.8949 w/m-K for Sample No.1 and 0.91886 w/m-K for Sample No.2; whereas the mean thermal resistances calculated were 30.4 I 65m/sup 2/-K/w and 29.6234m/sup 2/-K/w, respectively. The results obtained during this study are satisfactory and we hope that the insulation material prepared would be used in Pakistan in building constructions for heat resistance and insulation purposes. (author)

  16. Contribution of Ash Content Related to Methane Adsorption Behaviors of Bituminous Coals

    Directory of Open Access Journals (Sweden)

    Yanyan Feng

    2014-01-01

    Full Text Available Methane adsorption isotherms on coals with varying ash contents were investigated. The textural properties were characterized by N2 adsorption/desorption isotherm at 77 K, and methane adsorption characteristics were measured at pressures up to 4.0 MPa at 298 K, 313 K, and 328 K, respectively. The Dubinin-Astakhov model and the Polanyi potential theory were employed to fit the experimental data. As a result, ash content correlated strongly to methane adsorption capacity. Over the ash range studied, 9.35% to 21.24%, the average increase in methane adsorption capacity was 0.021 mmol/g for each 1.0% rise in ash content. With the increasing ash content range of 21.24%~43.47%, a reduction in the maximum adsorption capacities of coals was observed. In addition, there was a positive correlation between the saturated adsorption capacity and the specific surface area and micropore volume of samples. Further, this study presented the heat of adsorption, the isosteric heat of adsorption, and the adsorbed phase specific heat capacity for methane adsorption on various coals. Employing the proposed thermodynamic approaches, the thermodynamic maps of the adsorption processes of coalbed methane were conducive to the understanding of the coal and gas simultaneous extraction.

  17. Opportunities and challenges in the use of coal fly ash for soil improvements--a review.

    Science.gov (United States)

    Shaheen, Sabry M; Hooda, Peter S; Tsadilas, Christos D

    2014-12-01

    Coal fly ash (CFA), a by-product of coal combustion has been regarded as a problematic solid waste, mainly due to its potentially toxic trace elements, PTEs (e.g. Cd, Cr, Ni, Pb) and organic compounds (e.g. PCBs, PAHs) content. However, CFA is a useful source of essential plant nutrients (e.g. Ca, Mg, K, P, S, B, Fe, Cu and Zn). Uncontrolled land disposal of CFA is likely to cause undesirable changes in soil conditions, including contamination with PTEs, PAHs and PCBs. Prudent CFA land application offers considerable opportunities, particularly for nutrient supplementation, pH correction and ameliorating soil physical conditions (soil compaction, water retention and drainage). Since CFA contains little or no N and organic carbon, and CFA-borne P is not readily plant available, a mixture of CFA and manure or sewage sludge (SS) is better suited than CFA alone. Additionally, land application of such a mixture can mitigate the mobility of SS-borne PTEs, which is known to increase following cessation of SS application. Research analysis further shows that application of alkaline CFA with or without other amendments can help remediate at least marginally metal contaminated soils by immobilisation of mobile metal forms. CFA land application with SS or other source of organic carbon, N and P can help effectively reclaim/restore mining-affected lands. Given the variability in the nature and composition of CFA (pH, macro- and micro-nutrients) and that of soil (pH, texture and fertility), the choice of CFA (acidic or alkaline and its application rate) needs to consider the properties and problems of the soil. CFA can also be used as a low cost sorbent for the removal of organic and inorganic contaminants from wastewater streams; the disposal of spent CFA however can pose further challenges. Problems in CFA use as a soil amendment occur when it results in undesirable change in soil pH, imbalance in nutrient supply, boron toxicity in plants, excess supply of sulphate and PTEs

  18. Nuclear techniques for analysis of coal for calorific value, ash and moisture

    International Nuclear Information System (INIS)

    This bibliography includes references on nuclear techniques for analysis of coal for calorific value, ash and moisture content. As the search was directed particularly towards measurement of the ash content of coal using x- and gamma-ray methods, references covering only β-ray techniques have been placed in a separate section. References from Chemical Abstracts prior vol.62 (1965) do not cite the language of the original article. The language of the original has been given for all other articles not in English. (author)

  19. Conceptual flow sheets development for coal conversion plant coal handling-preparation and ash/slag removal operations

    Energy Technology Data Exchange (ETDEWEB)

    1979-07-01

    This report presents 14 conceptual flow sheets and major equipment lists for coal handling and preparation operations that could be required for future, commercial coal conversion plants. These flow sheets are based on converting 50,000 tons per day of clean coal representative of the Pittsburgh and Kentucky No. 9 coal seams. Flow sheets were used by Union Carbide Corporation, Oak Ridge National Laboratory, in a survey of coal handling/preparation equipment requirements for future coal conversion plants. Operations covered in this report include run-of-mine coal breaking, coarse coal cleaning, fine coal cleaning, live storage and blending, fine crushing (crushing to top sizes ranging from 1/4-inch to 20 mesh), drying, and grinding (70 percent minus 200 mesh). Two conceptual flow sheets and major equipment lists are also presented for handling ash or granulated slag and other solid wastes produced by nine leading coal conversion processes. These flow sheets provide for solid wastes transport to an environmentally acceptable disposal site as either dry solids or as a water slurry.

  20. In situ measurements of the spectral emittance of coal ash deposits

    International Nuclear Information System (INIS)

    The spectral emittance of deposits left by bituminous and sub-bituminous coals under oxidizing conditions have been measured in situ. Pulverized coal is injected into a down-fired entrained-flow reactor. Ash accumulates on a probe in the reactor effluent and radiation emitted by the ash layer is recorded using a Fourier transform infrared (FTIR) spectrometer. Values for the spectral emissive power emitted by the ash and the surface temperature of the ash are extracted from these data. These results are then used to calculate the spectral emittance of the deposit. The spectral emittances of ash deposits formed by burning Illinois no. 6 (bituminous) coal and Powder River Basin (sub-bituminous) coal were measured between 3000 and 500 wavenumbers. The spectral emittance of the deposit left by the bituminous coal has a constant value of approximately 0.46 between 3000 and 2400 wavenumbers. Between 2200 and 1200 wavenumbers, the spectral emittance of the deposit increases from approximately 0.47 to approximately 0.61. Between 1200 and 500 wavenumbers, the spectral emittance is relatively constant at 0.61. The spectral emittance of the deposit left by the sub-bituminous coal is also relatively constant between 3000 and 2400 wavenumbers at a value of 0.29. Between 2200 and 500 wavenumbers, the spectral emittance of deposits from the sub-bituminous coal increases from approximately 0.29 to 0.55. Differences between these spectral emittance measurements and those measured ex situ illustrate the importance of making in situ measurements. Band emittances were calculated using the measured spectral emittances, and band emittances of the deposits are reported as functions of temperature.

  1. Contribution of Ash Content Related to Methane Adsorption Behaviors of Bituminous Coals

    OpenAIRE

    Yanyan Feng; Wen Yang; Wei Chu

    2014-01-01

    Methane adsorption isotherms on coals with varying ash contents were investigated. The textural properties were characterized by N2 adsorption/desorption isotherm at 77 K, and methane adsorption characteristics were measured at pressures up to 4.0 MPa at 298 K, 313 K, and 328 K, respectively. The Dubinin-Astakhov model and the Polanyi potential theory were employed to fit the experimental data. As a result, ash content correlated strongly to methane adsorption capacity. Over the ash range stu...

  2. Coal Fly Ash Ceramics: Preparation, Characterization, and Use in the Hydrolysis of Sucrose

    Directory of Open Access Journals (Sweden)

    Ricardo Pires dos Santos

    2014-01-01

    Full Text Available Coal ash is a byproduct of mineral coal combustion in thermal power plants. This residue is responsible for many environmental problems because it pollutes soil, water, and air. Thus, it is important to find ways to reuse it. In this study, coal fly ash, obtained from the Presidente Médici Thermal Power Plant, was utilized in the preparation of ceramic supports for the immobilization of the enzyme invertase and subsequent hydrolysis of sucrose. Coal fly ash supports were prepared at several compaction pressures (63.66–318.30 MPa and sintered at 1200°C for 4 h. Mineralogical composition (by X-ray diffraction and surface area were studied. The ceramic prepared with 318.30 MPa presented the highest surface area (35 m2/g and amount of immobilized enzyme per g of support (76.6 mg/g. In assays involving sucrose inversion, it showed a high degree of hydrolysis (around 81% even after nine reuses and 30 days’ storage. Therefore, coal fly ash ceramics were demonstrated to be a promising biotechnological alternative as an immobilization support for the hydrolysis of sucrose.

  3. Nano-mineralogical investigation of coal and fly ashes from coal-based captive power plant (India): An introduction of occupational health hazards

    International Nuclear Information System (INIS)

    Coal derived nano-particles has been received much concern recently around the world for their adverse effects on human health and the environment during their utilization. In this investigation the mineral matter present in some industrially important Indian coals and their ash samples are addressed. Coal and fly ash samples from the coal-based captive power plant in Meghalaya (India) were collected for different characterization and nano-mineralogy studies. An integrated application of advanced characterization techniques such as X-ray diffraction (XRD), High Resolution-Transmission Electron microscopy (HR-TEM)/(Energy Dispersive Spectroscopy) EDS/(selected-area diffraction pattern) SAED, Field Emission-Scanning Electron Microscopy (FE-SEM)/EDS analysis, and Mössbauer spectroscopy were used to know their extent of risks to the human health when present in coal and fly ash. The study has revealed that the coals contain mainly clay minerals, whilst glass fragments, spinel, quartz, and other minerals in lesser quantities were found to be present in the coal fly ash. Fly ash carbons were present as chars. Indian coal fly ash also found to contain nanominerals and ultrafine particles. The coal-fired power plants are observed to be the largest anthropogenic source of Hg emitted to the atmosphere and expected to increase its production in near future years. The Multi Walled Carbon Nano-Tubes (MWCNTs) are detected in our fly ashes, which contains residual carbonaceous matter responsible for the Hg capture/encapsulation. This detailed investigation on the inter-relationship between the minerals present in the samples and their ash components will also be useful for fulfilling the clean coal technology principles. - Highlights: • We research changes in the level of ultrafine and nanoparticles about coal–ash quality. • Increasing dates will increase human health quality in this Indian coal area. • Welfare effects depend on ex-ante or ex-post assumptions about

  4. Analysis of natural radionuclides in coal, slag and ash in coal-fired power plants in Serbia

    Directory of Open Access Journals (Sweden)

    Janković M.M.

    2011-01-01

    Full Text Available The radioactivity monitoring in the “Nikola Tesla”, “Kolubara”, “Morava” and “Kostolac” coal-fired power plants was performed by the Radiation and Environmental Protection Laboratory, Vinča Institute of nuclear sciences in the period 2003-2010. Monitoring included the analysis of soil, water, flying ash, slag, coal and plants. This paper presents the results of the radioactivity analysis of coal, ash and slag samples. Naturally occurring radionuclides 226Ra, 232Th, 40K, 235U, 238U, and 210Pb as well as the man-made radionuclide 137Cs were determined by gamma spectrometry using HPGe detector. The concentrations of pairs of radionuclides were statistically tested to determine the correlation between them. Based on the obtained results, health effect due to the activity of these radionuclides was estimated via radium equivalent (Raeq, external hazard index (Hex, external gamma absorbed dose rate ( and annual effective dose.

  5. Characteristics variation of coal combustion residues in an Indian ash pond.

    Science.gov (United States)

    Asokan, Pappu; Saxena, Mohini; Aparna, Asokan; Asolekar, Shyam R; Asoletar, Shyam R

    2004-08-01

    Coal-fired power plants all over the world are cited as one of the major sources that generate huge quantities of coal combustion residues (CCRs) as solid wastes. Most frequently CCRs are collected through electrostatic precipitators, mixed with bottom ash by hydraulic systems and deposited in ash ponds. The quality of the CCRs at different locations in one of the ash ponds in Central India was evaluated to understand the variation in characteristics with a view to effective utilization. Results revealed that the presence of fine particles (distance from the ash slurry inlet zone in the ash pond. Wide variations in the bulk density (800-980 kg m(-3)), porosity (45-57%) and water-holding capacity (57.5-75.7%) of CCRs were recorded. With increasing distance the pH of the CCRs decreased (from 9.0 to 8.2) and electrical conductivity increased (from 0.25 to 0.65 dS m(-3)). The presence of almost all the heavy metals in CCRs exhibited an increase with distance from the ash slurry discharge zone due to the increase in surface area (from 0.1038 to 2.3076 m2 g(-1)) of CCRs particles. The present paper describes the variation of characteristics of CCRs deposited in the ash pond and their potential applications.

  6. THE STUDY OF THE BASIC THEORY AND THE APPLICATION OF REMOVAL PYRITE AND ASH FROM FINE COAL WITH ELECTROSTATIC SEPARATOR

    Institute of Scientific and Technical Information of China (English)

    章新喜; 陈清加

    1996-01-01

    The effect of removing pyrite and ash from fine coal with electrostatic separator is determined by the electric property of coal, the distribution of corona ion and electrostatic field, and the disperse and even feed. The dielectric constant of coal and mineral matter is studied in this paper and the amendment has been made to survey theory. The oscillogram is adopted to study the distribution of corona ion and electrostatic field. The paper details the study of remoing pyrite and ash from fine coal, and the test results demonstrate the high efficiency of removing pyrite and ash with electrostatic separator.

  7. Magnetic susceptibility measurements to detect coal fly ash from the Kingston Tennessee spill in Watts Bar Reservoir

    International Nuclear Information System (INIS)

    An estimated 229 000 m3 of coal fly ash remains in the river system after dredging to clean-up the 2008 Tennessee Valley Authority (TVA) spill in Kingston, Tennessee. The ash is heterogeneous with clear, orange and black spheres and non-spherical amorphous particles. Combustion produces iron oxides that allow low field magnetic susceptibility (χLF) and percent frequency dependent susceptibility (χFD%) to be used to discriminate between coal fly ash and sediments native to the watershed. Riverbed samples with χLF greater than 3.0 × 10−6 m3/kg, have greater than 15% ash measured by optical point counting. χLF is positively correlated with total ash, allowing ash detection in riverbed sediments and at depth in cores. The ratio of ash sphere composition is altered by river transport introducing variability in χLF. Measurement of χLF is inexpensive, non-destructive, and a reliable analytical tool for monitoring the fate of coal ash in this fluvial environment. -- Highlights: ► Coal fly ash is composed of spheres (clear, orange, black) and amorphous particles. ► Black spheres dominate the magnetic susceptibility signal (χLF). ► The river sorts ash but maintains a ratio of clear: orange: black ash. ► χLF measurements can predict % ash spheres from simple linear regression. ► χLF can be used to track coal ash in the riverbed and in sediment cores. -- An application of magnetic susceptibility for tracking the distribution of coal fly ash within a river system after the 2008 TVA spill at Kingston, Tennessee

  8. The secondary release of mercury in coal fly ash-based flue-gas mercury removal technology.

    Science.gov (United States)

    He, Jingfeng; Duan, Chenlong; Lei, Mingzhe; Zhu, Xuemei

    2016-01-01

    The secondary release of mercury from coal fly ash is a negative by-product from coal-fired power plants, and requires effective control to reduce environmental pollution. Analysing particle size distribution and composition of the coal fly ash produced by different mercury removing technologies indicates that the particles are generally less than 0.5 mm in size and are composed mainly of SiO2, Al2O3, and Fe2O3. The relationships between mercury concentration in the coal fly ash, its particle size, and loss of ignition were studied using different mercury removing approaches. The research indicates that the coal fly ash's mercury levels are significantly higher after injecting activated carbon or brominating activated carbon when compared to regular cooperating-pollution control technology. This is particularly true for particle size ranges of >0.125, 0.075-0.125, and 0.05-0.075 mm. Leaching experiments revealed the secondary release of mercury in discarded coal fly ash. The concentration of mercury in the coal fly ash increases as the quantity of injecting activated carbon or brominating activated carbon increases. The leached concentrations of mercury increase as the particle size of the coal fly ash increases. Therefore, the secondary release of mercury can be controlled by adding suitable activated carbon or brominating activated carbon when disposing of coal fly ash. Adding CaBr2 before coal combustion in the boiler also helps control the secondary release of mercury, by increasing the Hg(2+) concentration in the leachate. This work provides a theoretical foundation for controlling and removing mercury in coal fly ash disposal.

  9. The secondary release of mercury in coal fly ash-based flue-gas mercury removal technology.

    Science.gov (United States)

    He, Jingfeng; Duan, Chenlong; Lei, Mingzhe; Zhu, Xuemei

    2016-01-01

    The secondary release of mercury from coal fly ash is a negative by-product from coal-fired power plants, and requires effective control to reduce environmental pollution. Analysing particle size distribution and composition of the coal fly ash produced by different mercury removing technologies indicates that the particles are generally less than 0.5 mm in size and are composed mainly of SiO2, Al2O3, and Fe2O3. The relationships between mercury concentration in the coal fly ash, its particle size, and loss of ignition were studied using different mercury removing approaches. The research indicates that the coal fly ash's mercury levels are significantly higher after injecting activated carbon or brominating activated carbon when compared to regular cooperating-pollution control technology. This is particularly true for particle size ranges of >0.125, 0.075-0.125, and 0.05-0.075 mm. Leaching experiments revealed the secondary release of mercury in discarded coal fly ash. The concentration of mercury in the coal fly ash increases as the quantity of injecting activated carbon or brominating activated carbon increases. The leached concentrations of mercury increase as the particle size of the coal fly ash increases. Therefore, the secondary release of mercury can be controlled by adding suitable activated carbon or brominating activated carbon when disposing of coal fly ash. Adding CaBr2 before coal combustion in the boiler also helps control the secondary release of mercury, by increasing the Hg(2+) concentration in the leachate. This work provides a theoretical foundation for controlling and removing mercury in coal fly ash disposal. PMID:26121324

  10. Upgrading of coal ashes and desulphurisation residues to provide high value products

    Energy Technology Data Exchange (ETDEWEB)

    Fitzgerald, F.D. [Mitsui Babcock Energy Limited, Renfrew (United Kingdom)

    1998-11-01

    The work reported formed part of a collaborative European Coal and Steel Community (ECSC)-supported project, co-ordinated by Mitsui Babcock Energy limited (MBEL), aimed at investigating the possibility of preparing ettringite (a calcium sulpho-aluminate hydrate, 3CaO.Al{sub 2}O{sub 3}.3CaSO{sub 4}.32H{sub 2}O)-based products and calcium sulpho-aluminated (CSA) cements from coal ashes and desulphurisation residues. A total of twenty five sets of samples of coal ash and desulphurisation residues have been collected from twenty two coal-fired power stations and industrial boiler plants (twenty sites) in seven European countries. All the samples were analysed and their suitability as feedstocks for ettringite synthesis and calcium sulphoaluminated cement production has been assessed. The following conclusions have been drawn: 1. Any Al{sub 2}O{sub 3}-bearing fly ash or mixed fly ash/desulphurisation residue is potentially suitable for use as a feedstock in ettringite synthesis or calcium sulphoaluminated cement production. Ashes with high Al{sub 2}O{sub 3} in glass contents are preferred. 2. Any gypsum is suitable for use as a feedstock in ettringite synthesis. 3. Any gypsum or calcium sulphite-bearing desulphurisation residue or mixed fly ash/desulphurisation residue is suitable for use as a feedstock in calcium sulphoaluminated cement production. 4. Feed material mixture composition requires to be optimised for any particular set of residues that are used as feedstocks. 5. Leaching tests on finished ettringite and calcium sulphoaluminated cement products would identify any problems resulting from the heavy metal contents of the ashes and desulphurisation residues. 24 refs., 4 tabs., 2 apps.

  11. Progression in sulfur isotopic compositions from coal to fly ash: Examples from single-source combustion in Indiana

    Science.gov (United States)

    Yaofa, Jiang; Elswick, E.R.; Mastalerz, Maria

    2008-01-01

    Sulfur occurs in multiple mineral forms in coals, and its fate in coal combustion is still not well understood. The sulfur isotopic composition of coal from two coal mines in Indiana and fly ash from two power plants that use these coals were studied using geological and geochemical methods. The two coal beds are Middle Pennsylvanian in age; one seam is the low-sulfur ( 5%) Springfield Coal Member of the Petersburg Formation. Both seams have ash contents of approximately 11%. Fly-ash samples were collected at various points in the ash-collection system in the two plants. The results show notable difference in ??34S for sulfur species within and between the low-sulfur and high-sulfur coal. The ??34S values for all sulfur species are exclusively positive in the low-sulfur Danville coal, whereas the ??34S values for sulfate, pyritic, and organic sulfur are both positive and negative in the high-sulfur Springfield coal. Each coal exhibits a distinct pattern of stratigraphic variation in sulfur isotopic composition. Overall, the ??34S for sulfur species values increase up the section in the low-sulfur Danville coal, whereas they show a decrease up the vertical section in the high-sulfur Springfield coal. Based on the evolution of ??34S for sulfur species, it is suggested that there was influence of seawater on peat swamp, with two marine incursions occurring during peat accumulation of the high-sulfur Springfield coal. Therefore, bacterial sulfate reduction played a key role in converting sulfate into hydrogen sulfide, sulfide minerals, and elemental sulfur. The differences in ??34S between sulfate sulfur and pyritic sulfur is very small between individual benches of both coals, implying that some oxidation occurred during deposition or postdeposition. The ??34S values for fly ash from the high-sulfur Springfield coal (averaging 9.7???) are greatly enriched in 34S relative to those in the parent coal (averaging 2.2???). This indicates a fractionation of sulfur isotopes

  12. Characterization of Fly Ash from Coal-Fired Power Plant and Their Properties of Mercury Retention

    Science.gov (United States)

    He, Ping; Jiang, Xiumin; Wu, Jiang; Pan, Weiguo; Ren, Jianxing

    2015-12-01

    Recent research has shown that fly ash may catalyze the oxidation of elemental mercury and facilitate its removal. However, the nature of mercury-fly ash interaction is still unknown, and the mechanism of mercury retention in fly ash needs to be investigated more thoroughly. In this work, a fly ash from a coal-fired power plant is used to characterize the inorganic and organic constituents and then evaluate its mercury retention capacities. The as-received fly ash sample is mechanically sieved to obtain five size fractions. Their characteristics are examined by loss on ignition (LOI), scanning electron microscope (SEM), energy dispersive X-ray detector (EDX), X-ray diffraction (XRD), and Raman spectra. The results show that the unburned carbon (UBC) content and UBC structural ordering decrease with a decreasing particle size for the five ashes. The morphologies of different size fractions of as-received fly ash change from the glass microspheres to irregular shapes as the particle size increases, but there is no correlation between particle size and mineralogical compositions in each size fraction. The adsorption experimental studies show that the mercury-retention capacity of fly ash depends on the particle size, UBC, and the type of inorganic constituents. Mercury retention of the types of sp2 carbon is similar to that of sp3 carbon.

  13. Sulfur-bearing coatings on fly ash from a coal-fired power plant: Composition, origin, and influence on ash alteration

    Science.gov (United States)

    Fishman, N.S.; Rice, C.A.; Breit, G.N.; Johnson, R.D.

    1999-01-01

    Fly ash samples collected from two locations in the exhaust stream of a coal-fired power plant differ markedly with respect to the abundance of thin (???0.1 ??m) sulfur-rich surface coatings that are observable by scanning electron microscopy. The coatings, tentatively identified as an aluminum-potassium-sulfate phase, probably form upon reaction between condensed sulfuric acid aerosols and glass surfaces, and are preferentially concentrated on ash exposed to exhaust stream gases for longer. The coatings are highly soluble and if sufficiently abundant, can impart an acidic pH to solutions initially in contact with ash. These observations suggest that proposals for ash use and predictions of ash behavior during disposal should consider the transient, acid-generating potential of some ash fractions and the possible effects on initial ash leachability and alteration. ?? 1998 Elsevier Science Ltd.

  14. Radon induced radiological impact of coal, fly ash and cement samples

    International Nuclear Information System (INIS)

    Coal and its by-product fly ash are technologically important materials being used for power generation and in the manufacture of bricks, sheets, cement, land-filling, etc., respectively. Increased interest in measuring radon concentration in coal, fly ash and cement is due to its health hazards and environmental pollution. As the presence of radon in the environment (indoor and outdoor), soil, ground water, oil and gas deposits contributes the largest fraction of the natural radiation dose to populations, tracking its concentration is thus of paramount importance for radiological protection. Samples of coal and fly ash were collected from different thermal power stations in northern India and cement samples from National Council for Cement and Building Materials, Ballabgarh (Haryana), India and were analysed for radon concentration. For the measurement, alpha sensitive LR-115 type II plastic track detectors were used. Based upon the available data, the annual effective dose and the lifetime fatality risk factors have been calculated. The radon concentration from coal samples varied from 433 ± 28 Bqm-3 to 2086 ± 28 Bqm-3. The radon concentration from fly ash samples varied from 748 ± 28 Bqm-3 to 1417 ± 111 Bqm-3 and from 158 Bqm-3 to 1810 Bqm-3 in cement samples, with an average of 624 ± 169 Bqm-3. (author)

  15. Evidence of Coal-Fly-Ash Toxic Chemical Geoengineering in the Troposphere: Consequences for Public Health

    Directory of Open Access Journals (Sweden)

    J. Marvin Herndon

    2015-08-01

    Full Text Available The widespread, intentional and increasingly frequent chemical emplacement in the troposphere has gone unidentified and unremarked in the scientific literature for years. The author presents evidence that toxic coal combustion fly ash is the most likely aerosolized particulate sprayed by tanker-jets for geoengineering, weather-modification and climate-modification purposes and describes some of the multifold consequences on public health. Two methods are employed: (1 Comparison of 8 elements analyzed in rainwater, leached from aerosolized particulates, with corresponding elements leached into water from coal fly ash in published laboratory experiments, and (2 Comparison of 14 elements analyzed in dust collected outdoors on a high-efficiency particulate air (HEPA filter with corresponding elements analyzed in un-leached coal fly ash material. The results show: (1 the assemblage of elements in rainwater and in the corresponding experimental leachate are essentially identical. At a 99% confidence interval, they have identical means (T-test and identical variances (F-test; and (2 the assemblage of elements in the HEPA dust and in the corresponding average un-leached coal fly ash are likewise essentially identical. The consequences on public health are profound, including exposure to a variety of toxic heavy metals, radioactive elements, and neurologically-implicated chemically mobile aluminum released by body moisture in situ after inhalation or through transdermal induction.

  16. Evidence of Coal-Fly-Ash Toxic Chemical Geoengineering in the Troposphere: Consequences for Public Health.

    Science.gov (United States)

    Herndon, J Marvin

    2015-08-11

    The widespread, intentional and increasingly frequent chemical emplacement in the troposphere has gone unidentified and unremarked in the scientific literature for years. The author presents evidence that toxic coal combustion fly ash is the most likely aerosolized particulate sprayed by tanker-jets for geoengineering, weather-modification and climate-modification purposes and describes some of the multifold consequences on public health. Two methods are employed: (1) Comparison of 8 elements analyzed in rainwater, leached from aerosolized particulates, with corresponding elements leached into water from coal fly ash in published laboratory experiments, and (2) Comparison of 14 elements analyzed in dust collected outdoors on a high-efficiency particulate air (HEPA) filter with corresponding elements analyzed in un-leached coal fly ash material. The results show: (1) the assemblage of elements in rainwater and in the corresponding experimental leachate are essentially identical. At a 99% confidence interval, they have identical means (T-test) and identical variances (F-test); and (2) the assemblage of elements in the HEPA dust and in the corresponding average un-leached coal fly ash are likewise essentially identical. The consequences on public health are profound, including exposure to a variety of toxic heavy metals, radioactive elements, and neurologically-implicated chemically mobile aluminum released by body moisture in situ after inhalation or through transdermal induction.

  17. Elemental content of aquatic organisms inhabiting a pond contaminated with coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Furr, A.K.

    1979-01-01

    Using neutron activation and other methods, 39 elements were determined in algae, aquatic weeds, dragon fly nymphs, newts, fish and muskrats from a pond contaminated by coal fly ash. The organisms contained several elements, including selenium, at concentrations markedly higher than those in controls.

  18. Secondary Industrial Minerals from Coal Fly Ash and Aluminium Anodising Waste Solutions

    NARCIS (Netherlands)

    Nugteren, H.W.

    2010-01-01

    Minerals that are extracted from the earth’s crust to be directly used for their properties are called industrial minerals. This research shows that such minerals can also be produced from industrial residues, hence the name secondary industrial minerals. In this thesis coal fly ash is chosen as on

  19. Ash transformation in suspension fired boilers co-firing coal and straw

    DEFF Research Database (Denmark)

    Zheng, Yuanjing; Jensen, Peter Arendt; Jensen, Anker Degn

    To study the influence of local conditions on the reaction between gaseous KCl and kaolin or coal fly ash experiments were done on CHECs electrically heated entrained flow reactor, which can simulate the local conditions in suspension fired boilers. The experimental results were compared with model...

  20. Waste Water Treatment-Bed of Coal Fly Ash for Dyes and Pigments Industry

    International Nuclear Information System (INIS)

    The highly porous power plant waste ashes have been utilized to treat toxic effluent of a dyes manufacturing plant. An attempt has been made for the first time in Pakistan, to generate an effective and economically sound treatment facility for the toxic effluent of a dyes manufacturing plant. This is an indigenous bed which could replace expensive treatment facilities, such as reverse osmosis (RO), granulated activated carbon (GAC) bed, etc. The treatment efficiency was improved by coupling coagulants with fly ash adsorbent bed. The ash was collected from coal fired boilers of power plant at Lakhra Power Generation Company, Jamshoro, Pakistan. The use of this ash resolved the disposal and environmental issues by treating wastewater of chemical, dyes and pigment industry. The treatment bed comprised of briquettes of coal fly ash coupled with commercial coagulant ferrous sulfate-lime reduced COD, color, turbidity and TSS of effluent remarkably. An adsorption capacity and chemical behavior of fly ash bed was also studied. In coagulation treatment, coagulant FeSO/sun 4/-lime influenced reduction of COD, color, turbidity and TSS by 32 percentage, 48 percentage, 50 percentage and 51 percentage, respectively. The CFAB coupled with coagulant, resulted an excessive removal of color, TSS, COD, and turbidity by 88 percentage, 92 percentage, 67 percentage and 89 percentage, respectively. (author)

  1. Waste Water Treatment-Bed of Coal Fly Ash for Dyes and Pigments Industry

    Directory of Open Access Journals (Sweden)

    Syed Farman Ali Shah

    2015-12-01

    Full Text Available The highly porous power plant waste ashes have been utilized to treat toxic effluent of a dyes manufacturing plant. An attempt has been made for the first time in Pakistan, to generate an effective and economically sound treatment facility for the toxic effluent of a dyes manufacturing plant. This is an indigenous bed which could replace expensive treatment facilities, such as reverse osmosis (RO, granulated activated carbon (GAC bed, etc. The treatment efficiency was improved by coupling coagulants with fly ash adsorbent bed. The ash was collected from coal fired boilers of power plant at Lakhra Power Generation Company, Jamshoro, Pakistan. The use of this ash resolved the disposal and environmental issues by treating wastewater of chemical, dyes and pigment industry. The treatment bed comprised of briquettes of coal fly ash coupled with commercial coagulant ferrous sulfate-lime reduced COD, color, turbidity and TSS of effluent remarkably. An adsorption capacity and chemical behavior of fly ash bed was also studied. In coagulation treatment, coagulant FeSO4-lime influenced reduction of COD, color, turbidity and TSS by 32%, 48%, 50% and 51%, respectively. The CFAB coupled with coagulant, resulted an excessive removal of color, TSS, COD, and turbidity by 88%, 92%, 67% and89%, respectively.

  2. Potential of Hazardous Waste Encapsulation in Concrete Compound Combination with Coal Ash and Quarry Fine Additives.

    Science.gov (United States)

    Lieberman, Roy Nir; Anker, Yaakov; Font, Oriol; Querol, Xavier; Mastai, Yitzhak; Knop, Yaniv; Cohen, Haim

    2015-12-15

    Coal power plants are producing huge amounts of coal ash that may be applied to a variety of secondary uses. Class F fly ash may act as an excellent scrubber and fixation reagent for highly acidic wastes, which might also contain several toxic trace elements. This paper evaluates the potential of using Class F fly ashes (<20% CaO), in combination with excessive fines from the limestone quarry industry as a fixation reagent. The analysis included leaching experiments (EN12457-2) and several analytical techniques (ICP, SEM, XRD, etc.), which were used in order to investigate the fixation procedure. The fine sludge is used as a partial substitute in concrete that can be used in civil engineering projects, as it an environmentally safe product. PMID:26510011

  3. Sulfur retention by ash during coal combustion. Part I. A model of char particle combustion

    Directory of Open Access Journals (Sweden)

    BORISLAV GRUBOR

    2003-02-01

    Full Text Available A model for the combustion of porous char particles as a basis for modeling the process of sulfur retention by ash during coal combustion is developed in this paper. The model belongs to the microscopic intrinsic models and describes the dynamic behavior of a porous char particle during comustion, taking into account temporal and spatial changes of all important physical properties of the char particle and various combustion parameters. The parametric analysis of the enhanced model shows that the model represents a good basis for the development of a model for the process of sulfur retention by ash during coal combustion. The model enables the prediction of the values of all parameters necessary for the introduction of reactions between sulfur compounds and mineral components in ash, primarily calcium oxide.

  4. Potential of Hazardous Waste Encapsulation in Concrete Compound Combination with Coal Ash and Quarry Fine Additives.

    Science.gov (United States)

    Lieberman, Roy Nir; Anker, Yaakov; Font, Oriol; Querol, Xavier; Mastai, Yitzhak; Knop, Yaniv; Cohen, Haim

    2015-12-15

    Coal power plants are producing huge amounts of coal ash that may be applied to a variety of secondary uses. Class F fly ash may act as an excellent scrubber and fixation reagent for highly acidic wastes, which might also contain several toxic trace elements. This paper evaluates the potential of using Class F fly ashes (quarry industry as a fixation reagent. The analysis included leaching experiments (EN12457-2) and several analytical techniques (ICP, SEM, XRD, etc.), which were used in order to investigate the fixation procedure. The fine sludge is used as a partial substitute in concrete that can be used in civil engineering projects, as it an environmentally safe product.

  5. Influence of several experimental parameters on As and Se leaching from coal fly ash samples

    Energy Technology Data Exchange (ETDEWEB)

    Otero-Rey, Jose R. [Department of Analytical Chemistry, Faculty of Sciences, University of A Coruna, Campus da Zapateira s/n, E-15071 A Coruna (Spain); Mato-Fernandez, Maria J. [Department of Analytical Chemistry, Faculty of Sciences, University of A Coruna, Campus da Zapateira s/n, E-15071 A Coruna (Spain); Moreda-Pineiro, Jorge [Department of Analytical Chemistry, Faculty of Sciences, University of A Coruna, Campus da Zapateira s/n, E-15071 A Coruna (Spain); Alonso-Rodriguez, Elia [Department of Analytical Chemistry, Faculty of Sciences, University of A Coruna, Campus da Zapateira s/n, E-15071 A Coruna (Spain)]. E-mail: elia@udc.es; Muniategui-Lorenzo, Soledad [Department of Analytical Chemistry, Faculty of Sciences, University of A Coruna, Campus da Zapateira s/n, E-15071 A Coruna (Spain); Lopez-Mahia, Purificacion [Department of Analytical Chemistry, Faculty of Sciences, University of A Coruna, Campus da Zapateira s/n, E-15071 A Coruna (Spain); Prada-Rodriguez, Dario [Department of Analytical Chemistry, Faculty of Sciences, University of A Coruna, Campus da Zapateira s/n, E-15071 A Coruna (Spain)

    2005-02-28

    Coal fly ash leaching process for As and Se is studied. Environmental parameters such as pH, temperature, solid-liquid ratio, particle size and leaching time are taken into account in order to simulate As and Se leaching process for disposal coal fly ash. Analysis of reference materials was carried out by using of hydride generation coupled to atomic fluorescence spectrometry. Plackett-Burman experimental design is used to know the significative parameters, and Box-Behnken experimental design is used to refine the results obtained for these significative parameters. pH and temperature shown a hardly influence in leaching process. Furthermore, leaching time was also significative. According our results, it may be assumed that percentage of As and Se leaching in experimental conditions tested is relatively low for acidic fly ashes.

  6. Aluminum recovery from coal fly ash by high temperature chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Wijatno, H.

    1977-10-01

    A study of aluminum recovery from power plant fly ash by high temperature chlorination was undertaken to demonstrate that fly ash could be a potential source of aluminum, iron and possibly silicon. Magnetic separation of the iron oxide served as a first step to alleviate the iron contamination problem. However, the agglomeration of some iron oxide with alumina and silica made it difficult to completely separate the iron from the fly ash. Further iron separation was achieved by chlorinating the nonmagnetic ash fraction at 550/sup 0/C for 30 minutes. This reduced the iron oxide content to less than 4 percent by weight. Chlorine flow rates affected the reaction rate much more drastically than temperatures. This suggested that diffusion was the major rate-controlling step. Besides Fe/sub 2/O/sub 3/, Al/sub 2/O/sub 3/ and SiO/sub 2/, other oxides such as CaO, K/sub 2/O, Na/sub 2/O and MgO might have complicated the alumina recovery by forming individual chlorides or complexes. Investigating methods for separating more Fe/sub 2/O/sub 3/, and possibly CaO, K/sub 2/O, Na/sub 2/O and MgO from the nonmagnetic ash fraction before chlorinating it is highly recommended.

  7. Assessment of ecotoxicological risks of element leaching from pulvarized coal ashes.

    OpenAIRE

    Jenner, H.A.

    1995-01-01

    This thesis describes the consequences of the disposal of the combustion residues of coal, especially the uptake of elements from such residues and their effects on various organisms. The effects on benthic organisms in fresh and in seawater are considered in the first two parts. The third part looks at the uptake of elements from coal residues and their effect on the growth of plants and worms.The central theme is the combustion residue known as pulverized fuel ash (PFA), or 'flyash'. Coal i...

  8. Ash removal plants in large power stations designed for higher ash contents in brown coal and the utilization of waste products

    Energy Technology Data Exchange (ETDEWEB)

    Neumann, G.; Nicko, K.H.; Weidlich, H.G.

    1984-12-01

    More than 80% of the electric power generated in the GDR is produced on the basis of raw brown coal. Mean ash concentrations of 18 to 20% in raw brown coal and calorific values of 7000 kJ/kg are quite common. This means a higher amount of combustion residues, e.g. slag, fly ash and fly dust. In consequence, ash removal technologies for coal-fired power plants are getting increasingly important. Most of the present systems are combinations of suction and pressure-pneumatic systems. The most widely used system consists of a conveying trough, a pressure vessel conveyor, and a dry ash bunker. This combination is economically efficient, easy to operate, and requires little maintenance.

  9. Solubility of ion and trace metals from stabilized sewage sludge by fly ash and alkaline mine tailing

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hongling; SUN Lina; SUN Tieheng

    2008-01-01

    Stabilized sewage sludge (SS) by fly ash (FA) and alkaline mine tailing as artificial soil,to be applied on the ecological rehabilitation at mining junkyards,offers a potentially viable utilization of the industrial by-product,as well as solves the shortage of soil resource in the mine area.An incubation experiment with different ratios of SS and FA was conducted to evaluate the solubility of ions and trace elements from stabilized sewage sludge.Results showed that fly ash offset a decrease in pH value of sewage sludge.The pH of (C) treatment (FA:SS=1:1) was stable and tended to neutrality.The SO42- and Cl- concentrations of the solution in the mixture were significantly decreased in the stabilized sewage sludge by alkaline fly ash and mine tailing,compared to the single SS treatment.Stabilized sewage sludge by FA weakened the nitrification of total nitrogen from SS when the proportion of FA in the mixture was more than 50%.The Cr,Ni,and Cu concentrations in the solution were gradually decreased and achieved a stable level after 22 days,for all treatments over the duration of the incubation.Moreover stabilized sewage sludge by fly ash and/or mine tailing notably decreased the trace metal solubility.The final Cr,Cu,and Ni concentrations in the solution for all mixtures of treatments were lower than 2.5,15,and 50 μg/L,respectively.

  10. Effects of coal fly ash-amended composts on the yield and elemental uptake by plants

    International Nuclear Information System (INIS)

    The objective of this study was to determine the feasibility of coal fly ash-amended composts for use as an alternate manure for agricultural crops. Home-made organic composts was mixed in various proportions with fine fly ash collected from Savannah River Site, and allowed to decompose for two weeks while the mixture was kept wet. Water extracts from the amended composts were analyzed for selected major and trace elements. These amended composts were mixed with sifted sandy loam soil in a predetermined optimum ratio of 1:3 and used to grow corn and sorghum plants. It was shown that fly ash additions to home-made compost facilitated efficient plant utilization of nutrients when 20-40% fly ash in compost was applied to the soil. The maximum dry shoot yields correlated with the higher concentrations of K, Ca and N and lower concentrations of B in the amended compost treatment

  11. Studying the melting behavior of coal, biomass, and coal/biomass ash using viscosity and heated stage XRD data

    DEFF Research Database (Denmark)

    Arvelakis, Stelios; Folkedahl, B.; Dam-Johansen, Kim;

    2006-01-01

    high-temperature rotational viscometer and a hot stage XRD. The produced data were used to calculate the operating temperature of a pilot-scale entrained flow reactor during the cocombustion of biomass/ coal samples in order to ensure the slag flow and to avoid corrosion of the walls due to liquid slag......The use of biomass for power generation can result in significant economical and environmental benefits. The greenhouse emissions can be reduced as well as the cost of the produced electricity. However, ash-related problems, including slagging, agglomeration, and corrosion, can cause frequent...... unscheduled shutdowns, decreasing the availability and increasing the cost of the produced power. In addition, the fouling of the heat exchange surfaces reduces the system efficiency. In this work the melting and rheological properties of various biomass and biomass/ coal ash samples were studied by using a...

  12. Phosphorus Treated Coal Combustion Products (CCP-bottom ash) as an Agricultural Source of Phosphorus

    Science.gov (United States)

    Junfeng, Shen; Powell, M. A.; Hayden, D. B.

    Coal combustion products (CCP or "ash") have been seen to be beneficial for improving soil quality and increasing vegetative yields. Owing to their structure with more holes, they are also potential carriers of plant nutrients. The bottom ash from the Lambton Generating Station, Sarnia, Ontario, Canada was treated for 66 hours in 0.10 mol/L P solutions prepared from NaH 2PO 4, which resulted in the ash adsorbing 784 µg/g of phosphorus. The ash was mixed with quartz sand and/or non P-loaded ash from the same source to provide a set of growth media that contained 10%, 25%, 50%, 75%, and 100% of the recommended dose of P (50 µg/g) for maize. Biomass yields at 26, 34, and 46 days after planting were compared with control (non-doped ash) and fertilized with 0-20-0 fertilizer. In general, growth media containing between 25% and 100% of the recommended P dose performed as well or better than the fertilized trials. 46 days after planting, the shoot fresh weight for the 50%, 75%, and 100% doped media were 39.46%, 42.73%, and 46.13%, respectively, greater compared to fertilized trials. The shoot dry weight increased by 29.71%, 13.39%, and 28.87%, respectively. Also, root fresh and dry weight increased averagely by 16.62% and 14.03%. These results implied that coal ashes are a better carrier for P uptaking, and P-loaded ash can be a good additive for sand soil improvement.

  13. INVESTIGATION OF FLY ASH AND ACTIVATED CARBON OBTAINED FROM PULVERIZED COAL BOILERS

    Energy Technology Data Exchange (ETDEWEB)

    Edward K. Levy; Christopher Kiely

    2005-11-01

    One of the techniques for Hg capture in coal-fired boilers involves injection of activated carbon (AC) into the boiler downstream of the air preheater. Hg is adsorbed onto the AC particles and fly ash, which are then both removed in an electrostatic precipitator or baghouse. This project addresses the issues of Hg on activated carbon and on fly ash from a materials re-use point of view. It also addresses the possible connection between SCR reactors, fly ash properties and Hg capture. The project is determining the feasibility of separating AC from fly ash in a fluidized bed and of regenerating the separated AC by heating the AC to elevated temperatures in a fluidized bed. The temperatures needed to drive off the Hg from the ash in a fluidized bed are also being determined. Finally, samples of fly ash from power plants with SCR reactors for NO{sub x} control, are being analyzed to determine the effect of SCR on the ash.

  14. Investigation of Fly Ash and Activated Carbon Obtained from Pulverized Coal Boilers

    Energy Technology Data Exchange (ETDEWEB)

    Edward K. Levy; Christopher Kiely; Zheng Yao

    2006-08-31

    One of the techniques for Hg capture in coal-fired boilers involves injection of activated carbon (AC) into the boiler downstream of the air preheater. Hg is adsorbed onto the AC particles and fly ash, which are then both removed in an electrostatic precipitator or baghouse. This project addressed the issues of Hg on activated carbon and on fly ash from a materials re-use point of view. It also addressed the possible connection between SCR reactors, fly ash properties and Hg capture. The project has determined the feasibility of separating AC from fly ash in a fluidized bed and of regenerating the separated AC by heating the AC to elevated temperatures in a fluidized bed. The temperatures needed to drive off the Hg from the ash in a fluidized bed have also been determined. Finally, samples of fly ash from power plants with SCR reactors for NO{sub x} control have been analyzed in an effort to determine the effects of SCR on the ash.

  15. Effect of mixes made of coal bottom ash and fly ash on the mechanical strength and porosity of Portland cement

    Directory of Open Access Journals (Sweden)

    Argiz, C.

    2013-03-01

    Full Text Available New additions to the cement are needed to achieve a more sustainable and durable construction material. Within this context, bottom ashes can be used as a main constituent of Portland cements when it is mixed in an optimized proportion with fly ashes. The mechanical characteristics of standarized mortars made of mixes of pulverized coal combustion bottom and fly ashes are studied. The mortars were made of ordinary Portland cement (CEM I 42.5 N and mixes of bottom ashes with fly ashes in similar proportions to those of CEM II/A-V, CEM II/B-V and CEM IV/A (V. Summing up, it can be said that the utilization of bottom ashes mixed with fly ashes in replacement levels from 0% to 100% do not affect significantively on the mechanical caracteristics of the mortars considered in the present study which had an addition maximum content of 35%.

    La utilización de nuevas adiciones en el cemento es necesaria con el fin de obtener un material más sostenible y durable. En este sentido, las cenizas de fondo o cenicero de las centrales termoeléctricas de carbón se podrían reciclar siendo empleadas como un componente principal de los cementos Portland. Se han estudiado las propiedades mecánicas de unos morteros normalizados elaborados con mezclas de cenizas volantes con cenizas de fondo fabricados con unos porcentajes similares a los correspondientes de los CEM II/A-V, CEM II/B-V y CEM IV/A (V. En conclusión, la utilización de mezclas de cenizas de fondo o cenicero con cenizas volantes sustituyendo a éstas últimas entre el 0% y el 100%, no influye significativamente en el comportamiento mecánico de los morteros estudiados en los que el contenido máximo de adición ha sido del 35%, si bien afecta a determinados aspectos microestructurales, como la cantidad y distribución de poros capilares.

  16. Leaching characteristics of toxic constituents from coal fly ash mixed soils under the influence of pH

    Energy Technology Data Exchange (ETDEWEB)

    Komonweeraket, Kanokwan [Department of Civil and Environmental Engineering, University of Wisconsin, Madison, WI 53706 (United States); Cetin, Bora, E-mail: bora.cetin@sdsmt.edu [College of Engineering, University of Georgia, Athens, GA 30602 (United States); Benson, Craig H., E-mail: chbenson@wisc.edu [Department of Civil and Environmental Engineering, University of Wisconsin, Madison, WI 53706 (United States); Aydilek, Ahmet H., E-mail: aydilek@umd.edu [Department of Civil and Environmental Engineering, University of Maryland, College Park, MD 20742 (United States); Edil, Tuncer B., E-mail: edil@engr.wisc.edu [Department of Civil and Environmental Engineering, University of Wisconsin, Madison, WI 53706 (United States)

    2015-04-15

    Highlights: • The impact of pH on the leaching of elements and metals from fly ash mixed soils. • Generally Ca, Cd, Mg, and Sr follows a cationic leaching pattern. • The leaching of As and Se shows an oxyanionic leaching pattern. • The leaching behavior of elements does not change based on material type. • Different fly ash types show different abilities in immobilizing trace elements. - Abstract: Leaching behaviors of Arsenic (As), Barium (Ba), Calcium (Ca), Cadmium (Cd), Magnesium (Mg), Selenium (Se), and Strontium (Sr) from soil alone, coal fly ash alone, and soil-coal fly ash mixtures, were studied at a pH range of 2–14 via pH-dependent leaching tests. Seven different types of soils and coal fly ashes were tested. Results of this study indicated that Ca, Cd, Mg, and Sr showed cationic leaching pattern while As and Se generally follows an oxyanionic leaching pattern. On the other hand, leaching of Ba presented amphoteric-like leaching pattern but less pH-dependent. In spite of different types and composition of soil and coal fly ash investigated, the study reveals the similarity in leaching behavior as a function of pH for a given element from soil, coal fly ash, and soil-coal fly ash mixtures. The similarity is most likely due to similar controlling mechanisms (e.g., solubility, sorption, and solid-solution formation) and similar controlling factors (e.g., leachate pH and redox conditions). This offers the opportunity to transfer knowledge of coal fly ash that has been extensively characterized and studied to soil stabilized with coal fly ash. It is speculated that unburned carbon in off-specification coal fly ashes may provide sorption sites for Cd resulting in a reduction in concentration of these elements in leachate from soil-coal fly ash mixture. Class C fly ash provides sufficient CaO to initiate the pozzolanic reaction yielding hydrated cement products that oxyanions, including As and Se, can be incorporated into.

  17. Leaching characteristics of toxic constituents from coal fly ash mixed soils under the influence of pH

    International Nuclear Information System (INIS)

    Highlights: • The impact of pH on the leaching of elements and metals from fly ash mixed soils. • Generally Ca, Cd, Mg, and Sr follows a cationic leaching pattern. • The leaching of As and Se shows an oxyanionic leaching pattern. • The leaching behavior of elements does not change based on material type. • Different fly ash types show different abilities in immobilizing trace elements. - Abstract: Leaching behaviors of Arsenic (As), Barium (Ba), Calcium (Ca), Cadmium (Cd), Magnesium (Mg), Selenium (Se), and Strontium (Sr) from soil alone, coal fly ash alone, and soil-coal fly ash mixtures, were studied at a pH range of 2–14 via pH-dependent leaching tests. Seven different types of soils and coal fly ashes were tested. Results of this study indicated that Ca, Cd, Mg, and Sr showed cationic leaching pattern while As and Se generally follows an oxyanionic leaching pattern. On the other hand, leaching of Ba presented amphoteric-like leaching pattern but less pH-dependent. In spite of different types and composition of soil and coal fly ash investigated, the study reveals the similarity in leaching behavior as a function of pH for a given element from soil, coal fly ash, and soil-coal fly ash mixtures. The similarity is most likely due to similar controlling mechanisms (e.g., solubility, sorption, and solid-solution formation) and similar controlling factors (e.g., leachate pH and redox conditions). This offers the opportunity to transfer knowledge of coal fly ash that has been extensively characterized and studied to soil stabilized with coal fly ash. It is speculated that unburned carbon in off-specification coal fly ashes may provide sorption sites for Cd resulting in a reduction in concentration of these elements in leachate from soil-coal fly ash mixture. Class C fly ash provides sufficient CaO to initiate the pozzolanic reaction yielding hydrated cement products that oxyanions, including As and Se, can be incorporated into

  18. Coal and coke - analysis and testing. Determination of trace elements. Coal, coke and fly-ash. Determination of fluorine content. Pyrohydrolysis method

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-06-29

    This Standard sets out a procedure for the pyrohydrolytic separation of fluorine from coal, coke and fly-ash and for determination of fluorine by gravimetric processing and either ion potentiometry or ion chromatography.

  19. Alpha radioactivity study in coal-ash of thermal power plant using solid state nuclear track detector

    International Nuclear Information System (INIS)

    Coal combustion in power plants in India produces large quantities coal related wastes, for example flyash and bottom ash. Coal is known to contain trace quantities of naturally occurring radionuclides including uranium. Thus coal ash is also expected to contain those radionuclides. Flyash has become the subject of worldwide interest because of its diverse uses as in the manufacturing of cement, bricks, blocks, etc. Due to presence of higher concentration of primordial radionuclide content it may cause a potential health risk to people. The power plant- ash, if not properly disposed, will be a serious threat to the ambient environment. So it is essential to investigate the presence of radioactivity in the coal ash samples collected from different thermal power plants. In the present work, an attempt has been made to estimate the alpha activity in the coal ash samples collected from Kolaghat Thermal Power Plant, West Bengal using CR-39 plates - a very useful solid state nuclear track detector (SSNTD). It is one of the largest thermal power generation centres in West Bengal. This thermal power plant uses sub-bituminous coal from the nearby coalfields. The alpha activity of the samples varies from 1052-3571 Bq/kg. The analysis indicates high level of alpha activity in both fly and bottom ash and the level of activity are maximum among all power plant flyash of India reported so far. (author)

  20. Slagging characteristics of molten coal ash on silicon-aluminum combustion liners of boiler

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In order to study the slagging characteristics of boiler combustion liners during pulverized coal stream combustion,the slag samples on the surface of combustion liner were investigated by X-ray diffractometry,scan electron microscopy and energy dispersive X-ray analysis,and the transformation characteristics of the compositions and crystal phases were studied.The results show that the size of slag granules decreases as the slagging temperature increases;the crystallinity of coal ash I reduces to about 48.6% when the temperature is increased up to 1 350 ℃,and that of the coal ash Ⅱ reduces to about 65% when the temperature is increased up to 1 500 ℃;the encroachment of molten coal ash to the combustion liner is strengthened.At the same time,the diffusion and the segregation of the compositions in combustion liners have selectivity,which is in favor of enhancing the content of crystal phases,weakening the conglutination among molten slag compositions and combustion liner,and avoiding yielding big clinkers.But the diffusion of the compositions in combustion liners increases the porosity and decreases the mechanical intensity of combustion liner,and makes the slag encroachment to the liner become more serious.

  1. The occurrence of gold in fly ash derived from high-Ge coal

    Science.gov (United States)

    Seredin, Vladimir V.; Dai, Shifeng

    2014-01-01

    We present the first data on the mode of occurrence of Au in fly ashes from the Wulantuga and Lincang power plants in China, which burn high-Ge coal. Gold occurs as fine-grained drop-like particles with a size of n*0.01-0.2 μm on the surface of the glass globules. These features of the Au particles are proof for Au condensation from the gas phase and deposition on the surface of fly ash in the cooler zone of the electrostatic precipitator and baghouse filter.

  2. Successive development of soil ecosystems at abandoned coal-ash landfills.

    Science.gov (United States)

    Pen-Mouratov, Stanislav; Shukurov, Nosir; Yu, Jun; Rakhmonkulova, Shakhnoza; Kodirov, Obidjon; Barness, Gineta; Kersten, Michael; Steinberger, Yosef

    2014-07-01

    The main goal of the present study was to determine the effect of the native vegetation on the successive development of the soil ecosystem at abandoned coal-ash landfills of the Angren coal-fired power plant in Uzbekistan. Two different landfills (one not in use for 3 years, termed newer, and the other not in use for 10 years, termed older) with different degrees of vegetation cover were chosen to assess the time and vegetation effects on soil biota and habitat development. The soil biotic structure, including soil microorganisms and soil free-living nematode communities, was investigated both at open plots and under different native plants at the coal-ash landfill area. The observed soil microorganisms were found to be the most important component of the observed ecosystems. Total abundance, biomass, species, trophic and sexual diversity of soil free-living nematodes, along with fungi and organic-matter content, were found to be correlated with trace metals. The nematode trophic and species abundance and diversity increased from the newer toward the older coal-ash landfills. The sex ratio of the nematode communities was found to be dependent on the environmental conditions of the study area, with the males being the most sensitive nematode group. All applied ecological indices confirmed that open landfill plots distant from plants are the most unfavorable areas for soil biota. In that respect, the native plants Alhagi maurorum Desv. and Tamarix sp. were found to be important environmental components for the natural remediation of a soil ecosystem in the coal-ash landfill area. PMID:24676936

  3. Coal fly ash-slag-based geopolymers: microstructure and metal leaching.

    Science.gov (United States)

    Izquierdo, Maria; Querol, Xavier; Davidovits, Joseph; Antenucci, Diano; Nugteren, Henk; Fernández-Pereira, Constantino

    2009-07-15

    This study deals with the use of fly ash as a starting material for geopolymeric matrices. The leachable concentrations of geopolymers were compared with those of the starting fly ash to evaluate the retention of potentially harmful elements within the geopolymer matrix. Geopolymer matrices give rise to a leaching scenario characterised by a highly alkaline environment, which inhibits the leaching of heavy metals but may enhance the mobilization of certain oxyanionic species. Thus, fly ash-based geopolymers were found to immobilize a number of trace pollutants such as Be, Bi, Cd, Co, Cr, Cu, Nb, Ni, Pb, Sn, Th, U, Y, Zr and rare earth elements. However, the leachable levels of elements occurring in their oxyanionic form such as As, B, Mo, Se, V and W were increased after geopolymerization. This suggests that an optimal dosage, synthesis and curing conditions are essential in order to obtain a long-term stable final product that ensures an efficient physical encapsulation.

  4. CO2 capture using fly ash from coal fired power plant and applications of CO2-captured fly ash as a mineral admixture for concrete.

    Science.gov (United States)

    Siriruang, Chaichan; Toochinda, Pisanu; Julnipitawong, Parnthep; Tangtermsirikul, Somnuk

    2016-04-01

    The utilization of fly ash as a solid sorbent material for CO2 capture via surface adsorption and carbonation reaction was evaluated as an economically feasible CO2 reduction technique. The results show that fly ash from a coal fired power plant can capture CO2 up to 304.7 μmol/g fly ash, consisting of 2.9 and 301.8 μmol/g fly ash via adsorption and carbonation, respectively. The CO2 adsorption conditions (temperature, pressure, and moisture) can affect CO2 capture performance of fly ash. The carbonation of CO2 with free CaO in fly ashes was evaluated and the results indicated that the reaction consumed most of free CaO in fly ash. The fly ashes after CO2 capture were further used for application as a mineral admixture for concrete. Properties such as water requirement, compressive strength, autoclave expansion, and carbonation depth of mortar and paste specimens using fly ash before and after CO2 capture were tested and compared with material standards. The results show that the expansion of mortar specimens using fly ash after CO2 capture was greatly reduced due to the reduction of free CaO content in the fly ash compared to the expansion of specimens using fresh fly ash. There were no significant differences in the water requirement and compressive strength of specimens using fly ash, before and after CO2 capture process. The results from this study can lead to an alternative CO2 capture technique with doubtless utilization of fly ash after CO2 capture as a mineral admixture for concrete. PMID:26803257

  5. CO2 capture using fly ash from coal fired power plant and applications of CO2-captured fly ash as a mineral admixture for concrete.

    Science.gov (United States)

    Siriruang, Chaichan; Toochinda, Pisanu; Julnipitawong, Parnthep; Tangtermsirikul, Somnuk

    2016-04-01

    The utilization of fly ash as a solid sorbent material for CO2 capture via surface adsorption and carbonation reaction was evaluated as an economically feasible CO2 reduction technique. The results show that fly ash from a coal fired power plant can capture CO2 up to 304.7 μmol/g fly ash, consisting of 2.9 and 301.8 μmol/g fly ash via adsorption and carbonation, respectively. The CO2 adsorption conditions (temperature, pressure, and moisture) can affect CO2 capture performance of fly ash. The carbonation of CO2 with free CaO in fly ashes was evaluated and the results indicated that the reaction consumed most of free CaO in fly ash. The fly ashes after CO2 capture were further used for application as a mineral admixture for concrete. Properties such as water requirement, compressive strength, autoclave expansion, and carbonation depth of mortar and paste specimens using fly ash before and after CO2 capture were tested and compared with material standards. The results show that the expansion of mortar specimens using fly ash after CO2 capture was greatly reduced due to the reduction of free CaO content in the fly ash compared to the expansion of specimens using fresh fly ash. There were no significant differences in the water requirement and compressive strength of specimens using fly ash, before and after CO2 capture process. The results from this study can lead to an alternative CO2 capture technique with doubtless utilization of fly ash after CO2 capture as a mineral admixture for concrete.

  6. Sulfur retention by ash during coal combustion. Part II. A model of the process

    Directory of Open Access Journals (Sweden)

    BRANIMIR JOVANCICEVIC

    2003-03-01

    Full Text Available An overall model for sulfur self-retention in ash during coal particle combustion is developed in this paper. It is assumed that sulfur retention during char combustion occurs due to the reaction between SO2 and CaO in the form of uniformly distributed non-porous grains. Parametric analysis shows that the process of sulfur self-retention is limited by solid difussion through the non-porous product layer formed on the CaO grains and that the most important coal characteristics which influence sulfur self-retention are coal rank, content of sulfur forms, molar Ca/S ratio and particle radius. A comparison with the experimentally obtained values in a FB reactor showed that the model can adequately predict the kinetics of the process, the levels of the obtained values of the SSR efficiencies, as well as the influence of temperature and coal particle size.

  7. Relating fish health and reproductive metrics to contaminant bioaccumulation at the Tennessee Valley Authority Kingston coal ash spill site.

    Science.gov (United States)

    Pracheil, Brenda M; Marshall Adams, S; Bevelhimer, Mark S; Fortner, Allison M; Greeley, Mark S; Murphy, Cheryl A; Mathews, Teresa J; Peterson, Mark J

    2016-08-01

    A 4.1 million m(3) coal ash release into the Emory and Clinch rivers in December 2008 at the Tennessee Valley Authority's Kingston Fossil Plant in east Tennessee, USA, prompted a long-term, large-scale biological monitoring effort to determine if there are chronic effects of this spill on resident biota. Because of the magnitude of the ash spill and the potential for exposure to coal ash-associated contaminants [e.g., selenium (Se), arsenic (As), and mercury (Hg)] which are bioaccumulative and may present human and ecological risks, an integrative, bioindicator approach was used. Three species of fish were monitored-bluegill (Lepomis macrochirus), redear sunfish (L. microlophus), and largemouth bass (Micropterus salmoides)-at ash-affected and reference sites annually for 5 years following the spill. On the same individual fish, contaminant burdens were measured in various tissues, blood chemistry parameters as metrics of fish health, and various condition and reproduction indices. A multivariate statistical approach was then used to evaluate relationships between contaminant bioaccumulation and fish metrics to assess the chronic, sub-lethal effects of exposure to the complex mixture of coal ash-associated contaminants at and around the ash spill site. This study suggests that while fish tissue concentrations of some ash-associated contaminants are elevated at the spill site, there was no consistent evidence of compromised fish health linked with the spill. Further, although relationships between elevated fillet burdens of ash-associated contaminants and some fish metrics were found, these relationships were not indicative of exposure to coal ash or spill sites. The present study adds to the weight of evidence from prior studies suggesting that fish populations have not incurred significant biological effects from spilled ash at this site: findings that are relevant to the current national discussions on the safe disposal of coal ash waste. PMID:27154845

  8. Feasibility studies of low energy #betta#-ray techniques for on-line determination of ash content of coal on conveyors

    International Nuclear Information System (INIS)

    Low energy #betta#-ray transmission measurements on suites of 100 kg samples from each of four different coal areas of Australia gave errors in ash determination of 0.99, 1.20, 1.59 and 2.24 wt% (1σ), respectively, for mean ash contents of 20.0, 27.1, 24.5 and 17.1 wt% ash. Calculations show that the main errors in ash determination are caused by variations of Fe2O3 in the ash, and the wt% ash error is proportional to the ash concentration. An error of about 0.5 wt% is predicted for washery product with ash content of 8 wt%. The most promising applications of low energy #betta#-ray techniques are for direct on-line determination of ash in washed coal, and for raw coal where accuracy required is not high or iron variations in the ash are small. (author)

  9. Effects of coal ash pollution on the genetic diversity of Brachionus calyciflorus based on rDNA ITS sequences

    OpenAIRE

    Xinli Wen; Xianling Xiang; Xin Hu; Yinghao Xue; Yilong Xi; Gen Zhang

    2010-01-01

    In this study, rDNA ITS sequences were analyzed to compare the genetic diversity of Brachionus calyciflorus from the coal ash contaminated (Lake Hui) and two uncontaminated lakes (Lake Tingtang and Lake Fengming). The results showed that two sibling species in Brachionus calyciflorus species complex were defined in both Lake Tingtang and Lake Fengming, but only one sibling species was found in Lake Hui. The coal ash pollution decreased the number of sibling species. Based on the sequences of ...

  10. Hydrothermal Synthesis of Zeolite from Coal Class F Fly Ash. Influence of Temperature

    Directory of Open Access Journals (Sweden)

    Goñi, S.

    2010-06-01

    Full Text Available The influence of temperature of alkaline hydrothermal treatment on the conversion in zeolite of Spanish coal low calcium-fly ash (ASTM class F is presented in this work. Zeolite Na-P1 gismondine type (Na6Al6Si10O32.12H2O was formed at the temperature of 100ºC, which transformed in zeolite; analcime-C type (Na(Si2AlO6H2O and sodalite (1.08 Na2O.Al2O3.1.68SiO2.1.8H2O at 200ºC together with traces of tobermorite-11Å (Ca5(OH2Si6O16.4H2O. At this temperature the 100% of the fly ash reaction was allowed. An equivalent study was carried out in water as reference. The zeolite conversion of the fly ash was characterized by X ray diffraction (XRD, FT infrared (FTIR spectroscopy, surface area (BET-N2 and thermal analyses.

    En este trabajo se presenta el papel que juega la temperatura durante el tratamiento hidrotermal en medio alcalino para convertir una ceniza volante de bajo contenido en cal (clase F, según la norma ASTM en zeolita. Durante este tratamiento a la temperatura de 100ºC se forma Zeolita Na-P1 tipo gismondina (Na6Al6Si10O32.12H2O; al elevar la temperatura a 200ºC, dicha zeolita se transforma en zeolita Analcima C (Na(Si2AlO6H2O y en fase sodalita (1.08 Na2O.Al2O3.1.68SiO2.1.8H2O junto con trazas de tobermorita-11Å (Ca5(OH2Si6O16.4H2O. A esta temperatura y en estas condiciones se ha conseguido un 100% de reacción. Un estudio equivalente se ha llevado a cabo empleando agua como medio de referencia. La conversión de ceniza volante en zeolita se ha caracterizado mediante técnicas, como difracción de Rayos X (DRX, espectroscopia

  11. Distribution of polycyclic aromatic hydrocarbons in fly ash during coal and residual char combustion in a pressurized fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Hongcang Zhou; Baosheng Jin; Rui Xiao; Zhaoping Zhong; Yaji Huang [Nanjing University of Information Science and Technology, Nanjing (China)

    2009-04-15

    To investigate the distribution of polycyclic aromatic hydrocarbons (PAHs) in fly ash, the combustion of coal and residual char was performed in a pressurized spouted fluidized bed. After Soxhlet extraction and Kuderna-Danish (K-D) concentration, the contents of 16 PAHs recommended by the United States Environmental Protection Agency (U.S. EPA) in coal, residual char, and fly ash were analyzed by a high-performance liquid chromatography (HPLC) coupled with fluorescence and diode array detection. The experimental results show that the combustion efficiency is lower and the carbon content in fly ash is higher during coal pressurized combustion, compared to the residual char pressurized combustion at the pressure of 0.3 MPa. Under the same pressure, the PAH amounts in fly ash produced from residual char combustion are lower than that in fly ash produced from coal combustion. The total PAHs in fly ash produced from coal and residual char combustion are dominated by three- and four-ring PAHs. The amounts of PAHs in fly ash produced from residual char combustion increase and then decrease with the increase of pressure in a fluidized bed. 21 refs., 1 fig., 4 tabs.

  12. Deposit formation in a full-scale pulverized wood-fired power plant with and without coal fly ash addition

    OpenAIRE

    Hao WU; Shafique Bashir, Muhammad; Jensen, Peter Arendt; Sander, Bo; Glarborg, Peter

    2013-01-01

    Ash transformation and deposition in a pulverized wood-fired power plant boiler of 800 MWth were studied with and without the addition of coal fly ash. The transient ash deposition behavior was investigated by using an advanced deposit probe system at two different boiler locations with flue gas temperatures of ~1300oC and ~800oC, respectively. It was found that during pulverized wood combustion, the deposit formation at the hightemperature location was characterized by a slow and continuous ...

  13. Synthesis and characterization of zeolite material from coal ashes modified by surfactant

    International Nuclear Information System (INIS)

    Coal ash was used as starting material for zeolite synthesis by means of hydrothermal treatment. The surfactant-modified zeolite (SMZ) was prepared by adsorbing the cationic surfactant hexadecyltrimethylammonium bromide (HDTMA-Br) on the external surface of the zeolite from coal ash. The zeolite structure stability was monitored during the characterization of the materials by FTIR, XDR and SEM. The structural parameters of surfactant-modified zeolite are very close to that of corresponding non-modified zeolite which indicates that the crystalline nature of the zeolite remained intact after required chemical treatment with HDTMA-Br molecules and heating treatment for drying. The most intense peaks in the FTIR spectrum of HDTMA-Br were observed in SMZ spectrum confirming adsorption of surfactant on zeolites. (author)

  14. Lognormal distribution of natural radionuclides in freshwater ecosystems and coal-ash repositories

    International Nuclear Information System (INIS)

    This study summarizes and analyses data for natural radionuclides, 40K, 226 Ra and 'Th, measured by gamma spectrometry in water samples, sediments and coal-ash samples collected from regional freshwater ecosystems and near-by coal-ash repositories during the last decade, 1986-1996, respectively. The frequency plots of natural radionuclide data, for which the hypothesis of the regional scale log normality was accepted, exhibited single population groups with exception of 226Ra and232Th data for waters. Thus the presence of break points in the frequency distribution plots indicated that 226Ra and 232Th data for waters do not come from a single statistical population. Thereafter the hypothesis of log normality was accepted for the separate population groups of 226 Ra and '-32 Th in waters. (authors)

  15. Zinc estimates in ore and slag samples and analysis of ash in coal samples

    International Nuclear Information System (INIS)

    Zinc estimates in ore and slag samples were made using the radioisotope X-ray fluorescence method. A 10 mCi 238Pu was employed as the primary source of radiation and a thin crystal NaI(Ti) spectrometer was used to accomplish the detection of the 8.64 keV Zinc K-characteristic X-ray line. The results are reported. Ash content of coal concerning about 100 samples from Ravindra Khani VI and VII mines in Andhra Pradesh were measured using X-ray backscattering method with compensation for varying concentrations of iron in different coal samples through iron-X-ray fluorescent intensity measurements. The ash percent is found to range from 10 to 40. (author)

  16. An investigation of radon exhalation rate and estimation of radiation doses in coal and fly ash samples.

    Science.gov (United States)

    Mahur, A K; Kumar, Rajesh; Mishra, Meena; Sengupta, D; Prasad, Rajendra

    2008-03-01

    Coal is a technologically important material used for power generation. Its cinder (fly ash) is used in the manufacturing of bricks, sheets, cement, land filling etc. Coal and its by-products often contain significant amounts of radionuclides, including uranium which is the ultimate source of the radioactive gas radon. Burning of coal and the subsequent atmospheric emission cause the redistribution of toxic radioactive trace elements in the environment. In the present study, radon exhalation rates in coal and fly ash samples from the thermal power plants at Kolaghat (W.B.) and Kasimpur (U.P.) have been measured using sealed Can technique having LR-115 type II detectors. The activity concentrations of 238U, 232Th, and 40K in the samples of Kolaghat power station are also measured. It is observed that the radon exhalation rate from fly ash samples from Kolaghat is higher than from coal samples and activity concentration of radionuclides in fly ash is enhanced after the combustion of coal. Fly ash samples from Kasimpur show no appreciable change in radon exhalation. Radiation doses from the fly ash samples have been estimated from radon exhalation rate and radionuclide concentrations.

  17. Alkaline disinfection of urban wastewater and landfill leachate by wood fly ash.

    Science.gov (United States)

    Ivanković, Tomislav; Hrenović, Jasna; Itskos, Grigorios; Koukouzas, Nikolaos; Kovačević, Davor; Milenković, Jelena

    2014-12-01

    Wood fly ash is an industrial by-product of the combustion of different wood materials and is mostly disposed of as waste on landfills. In our preliminary experiments, wood ash exhibited antibacterial activity against urban wastewater bacteria and we focused on wood fly ash as a potential substrate for wastewater disinfection. The addition of ash at a concentration of 10 g L⁻¹ (1%) caused an instant increase of pH in urban wastewater and landfill leachate. High pH (10.1-12.7) inactivated bacterial populations in the wastewater and the removal of faecal coliforms and intestinal enterococci after 6 h of contact was 100% (below the detection limit; ash sample (ash from combustion of beech) both in urban wastewater and landfill leachate. Properly chosen wood fly ash, i.e. one that tends to increase the pH to the greatest extent, proved to be a very effective disinfection substrate. Considering that water treated with wood ash has a high pH and needs to be neutralised before discharge, ash would be suitable for disinfection of leachates when smaller volumes are treated. PMID:25720024

  18. Experimental study on the rheological behaviour of coal ash slurries

    Directory of Open Access Journals (Sweden)

    Assefa K.M.

    2015-12-01

    Full Text Available Extensive experimental investigations were carried out to evaluate the rheological behaviour of fly ash (FA slurry without and with the addition of bottom ash (BA and BA slurry without and with the addition of FA. The FA slurries exhibited Bingham behaviour at solid mass concentrations ranging from 60–65% and mixing proportions from 10– 40%. A substantial reduction in yield stress was observed except for mixing proportion of 40% on which the yield stress and viscosity were increased drastically for all solid concentrations. Hence, it can be concluded that the yield stress and viscosity of FA slurry were very much influenced by adding BA up to the mixing proportion of 30%. The rheological behaviour of BA slurries with and without the addition of FA in proportions of 10–50% was investigated and exhibited Newtonian behaviours for solid mass concentrations ranging from 30–50% without and with the addition of FA. The viscosity increases with increasing the solid concentrations and proportion of FA. Based on these experimental data, a correlation was developed to predict the relative viscosity of BA slurries as a function of solid volume fraction and FA mass proportion of 0–50% and the RMSE and R2 values showed good agreement between the experimental and the predicted data.

  19. Assessment of compost application to coal ash disposal sites to promote the rapid vegetation establishment

    Science.gov (United States)

    Repmann, F.; Slazak, A.; Babic, M.; Schneider, B. U.; Schaaf, W.; Hüttl, R. F.

    2009-04-01

    In the city of Tuzla, located in Bosnia and Herzegovina, a coal fired thermo electric power plant is operated by the company JP ELEKTROPRIVERDA BIH TERMOELEKTRANA "TUZLA". High amounts of ash are produced by the power plant, which are currently disposed into settlement ponds bordered by dams in natural valleys. A total of four ash disposal sites covering an area of approx. 170 ha have been established during the last decades. Due to the fact that residual ash from coal combustion was found to contain a variety of trace elements (Ni, Cr, As, B), it must be assumed that ash disposal of that magnitude constitutes an environmental problem which is investigated within the EU-FP6 / STREP project "Reintegration of Coal Ash Disposal Sites and Mitigation of Pollution in the West Balkan Area" RECOAL. The main hazards relate to soil and groundwater contamination due to leaching toxins, dust dispersion, and toxins entering the food chain as these disposal sites are used for agricultural purposes. In order to rapidly establish a vegetation cover on barren ash dumps that particularly would prevent dust erosion we assessed the applicability of compost, produced from locally available municipal and industrial organic residues as an amendment to ash to improve substrate fertility. The envisaged remediation technology was considered to be a low cost, easy applicable and rapid method capable of substantially enhancing living conditions of residents in the vicinity of the abandoned disposal sites. Various compost application rates were evaluated in the field on experimental site Divkovici I in Tuzla and additionally in the greenhouse environment at Brandenburg Technical University Cottbus. Field and laboratory tests revealed that plant growth and cover rate can substantially be improved by mixing compost into the upper ash layer to a maximum depth of approx. 20 cm. Besides direct growth observations in the field analysis of soil parameters gave evidence that the fertility of ashy

  20. Sequestration of carbon dioxide by indirect mineralization using Victorian brown coal fly ash.

    Science.gov (United States)

    Sun, Yong; Parikh, Vinay; Zhang, Lian

    2012-03-30

    The use of an industry waste, brown coal fly ash collected from the Latrobe Valley, Victoria, Australia, has been tested for the post-combustion CO(2) capture through indirect minersalization in acetic acid leachate. Upon the initial leaching, the majority of calcium and magnesium in fly ash were dissolved into solution, the carbonation potential of which was investigated subsequently through the use of a continuously stirred high-pressure autoclave reactor and the characterization of carbonation precipitates by various facilities. A large CO(2) capture capacity of fly ash under mild conditions has been confirmed. The CO(2) was fixed in both carbonate precipitates and water-soluble bicarbonate, and the conversion between these two species was achievable at approximately 60°C and a CO(2) partial pressure above 3 bar. The kinetic analysis confirmed a fast reaction rate for the carbonation of the brown coal ash-derived leachate at a global activation energy of 12.7 kJ/mol. It is much lower than that for natural minerals and is also very close to the potassium carbonate/piperazine system. The CO(2) capture capacity of this system has also proven to reach maximum 264 kg CO(2)/ton fly ash which is comparable to the natural minerals tested in the literature. As the fly ash is a valueless waste and requires no comminution prior to use, the technology developed here is highly efficient and energy-saving, the resulting carbonate products of which are invaluable for the use as additive to cement and in the paper and pulp industry. PMID:22326240

  1. Heavy metal leaching from coal fly ash amended container substrates during Syngonium production.

    Science.gov (United States)

    Li, Qiansheng; Chen, Jianjun; Li, Yuncong

    2008-02-01

    Coal fly ash has been proposed to be an alternative to lime amendment and a nutrient source of container substrates for ornamental plant production. A great concern over this proposed beneficial use, however, is the potential contamination of surface and ground water by heavy metals. In this study, three fly ashes collected from Florida, Michigan, and North Carolina and a commercial dolomite were amended in a basal substrate. The formulated substrates were used to produce Syngonium podophyllum Schott 'Berry Allusion' in 15-cm diameter containers in a shaded greenhouse. Leachates from the containers were collected during the entire six months of plant production and analyzed for heavy metal concentrations. There were no detectable As, Cr, Hg, Pb, and Se in the leachates; Cd and Mo were only detected in few leachate samples. The metals constantly detected were Cu, Mn, Ni, and Zn. The total amounts of Cu, Mn, Ni, and Zn leached during the six-month production period were 95, 210, 44, and 337 microg per container, indicating that such amounts in leachates may contribute little to contamination of surface and ground water. In addition, plant growth indices and fresh and dry weights of S. podophyllum 'Berry Allusion' produced from fly ash and dolomite-amended substrates were comparable except for the plants produced from the substrate amended with fly ash collected from Michigan which had reduced growth indices and fresh and dry weights. Thus, selected fly ashes can be alternatives to commercial dolomites as amendments to container substrates for ornamental plant production. The use of fly ashes as container substrate amendments should represent a new market for the beneficial use of this coal combustion byproduct.

  2. Heavy metal leaching from coal fly ash amended container substrates during Syngonium production

    Energy Technology Data Exchange (ETDEWEB)

    Li, Q.S.; Chen, J.J.; Li, Y.C. [University of Florida, Apopka, FL (United States)

    2008-02-15

    Coal fly ash has been proposed to be an alternative to lime amendment and a nutrient source of container substrates for ornamental plant production. A great concern over this proposed beneficial use, however, is the potential contamination of surface and ground water by heavy metals. In this study, three fly ashes collected from Florida, Michigan, and North Carolina and a commercial dolomite were amended in a basal substrate. The formulated substrates were used to produce Syngonium podophyllum Schott 'Berry Allusion' in 15-cm diameter containers in a shaded greenhouse. Leachates from the containers were collected during the entire six months of plant production and analyzed for heavy metal concentrations. There were no detectable As, Cr, Hg, Pb, and Se in the leachates; Cd and Mo were only detected in few leachate samples. The metals constantly detected were Cu, Mn, Ni, and Zn. The total amounts of Cu, Mn, Ni, and Zn leached during the six-month production period were 95, 210, 44, and 337 {mu} g per container, indicating that such amounts in leachates may contribute little to contamination of surface and ground water. In addition, plant growth indices and fresh and dry weights of S. podophyllum 'Berry Allusion' produced from fly ash and dolomite-amended substrates were comparable except for the plants produced from the substrate amended with fly ash collected from Michigan which had reduced growth indices and fresh and dry weights. Thus, selected fly ashes can be alternatives to commercial dolomites as amendments to container substrates for ornamental plant production. The use of fly ashes as container substrate amendments should represent a new market for the beneficial use of this coal combustion byproduct.

  3. The Character of Dual Site Adsorbent on Coal Fly Ash Toward Benzene Adsorption

    Directory of Open Access Journals (Sweden)

    Widi Astuti

    2014-10-01

    Full Text Available Large quantities of coal fly ash (CFA are produced during combustion of coal in the production of electricity. Most of this ash has not been widely used. CFA is mainly composed of some oxides including Al2O3 and SiO2 having active site and unburnedcarbon as a mesopore that enables it to act as a dual site adsorbent. To get different characters of dual site, CFA was sieved using 150 mesh size, heated at 400oC and reactedwith sodium hydroxide solution. Furthermore, CFA was used as adsorbent of benzene in aqueous solutions. Equilibrium data were evaluated by single site and dual site isotherm models. It can be concluded that single site model yielded excellent fit with equilibrium data of benzene. The values of maximum concentration of adsorbate in solid surface (Cμm and Langmuir constant (KL are affected by [Si+Al]/C ratio in CFA. The increase of [Si+Al]/C ratio causes a decrease of qm and KL values.Keywords : coal fly ash, adsorption, benzene

  4. Laser Induced Breakdown Spectroscopy machine for online ash analyses in coal

    International Nuclear Information System (INIS)

    Presently, online coal ash content monitoring is performed by PGNAA (Prompt Gamma Neutron Activation Analyses) machines. Laser Detect Systems has developed an online mineral analysis system using Laser Induced Breakdown Spectroscopy (LIBS). The main advantages of the system are that it is without a radioactive source, compact (1.5 m x 0.8 m x 1.3 m), comparatively light (250 kg) and easy to install. The main disadvantage is that a LIBS system analyzes surface chemistry of the mineral exclusively and not the volume. To prove the LIBS machine analytical ability for coal ash content evaluation, a trial was arranged at Optimum Colliery (South Africa). The LIBS machine was installed in line with a PGNAA machine and laboratory data served as a referee in the final assessment for analytical accuracy. The trial was carried out over a four month period. This paper presents the successful trial results achieved for accurate (at least +/- 0.5% mean absolute error) online coal ash content monitoring

  5. New methodology for assessing the environmental burden of cement mortars with partial replacement of coal bottom ash and fly ash.

    Science.gov (United States)

    Menéndez, E; Álvaro, A M; Hernández, M T; Parra, J L

    2014-01-15

    This paper assess the mechanical an environmental behaviour of cement mortars manufactured with addition of fly ash (FA) and bottom ash (BA), as partial cement replacement (10%, 25% and 35%). The environmental behaviour was studied by leaching tests, which were performed under several temperature (23 °C and 60 °C) and pH (5 and 10) conditions, and ages (1, 2, 4 and 7 days). Then, the accumulated amount of the different constituents leached was analysed. In order to obtain an environmental burden (EB) value of each cement mixture, a new methodology was developed. The EB value obtained is related to the amount leached and the hazardous level of each constituent. Finally, the integral study of compressive strength and EB values of cement mixtures allowed their classification. The results showed that mortars manufactured with ordinary Portland cement (OPC) and with coal BA had similar or even better environmental and mechanical behaviour than mortars with FA. Therefore, the partial replacement of cement by BA might be as suitable or even better as the replacement by FA.

  6. Multivariable Regression and Adaptive Neurofuzzy Inference System Predictions of Ash Fusion Temperatures Using Ash Chemical Composition of US Coals

    Directory of Open Access Journals (Sweden)

    Shahab Karimi

    2014-01-01

    Full Text Available In this study, the effects of ratios of dolomite, base/acid, silica, SiO2/Al2O3, and Fe2O3/CaO, base and acid oxides, and 11 oxides (SiO2, Al2O3, CaO, MgO, MnO, Na2O, K2O, Fe2O3, TiO2, P2O5, and SO3 on ash fusion temperatures for 1040 US coal samples from 12 states were evaluated using regression and adaptive neurofuzzy inference system (ANFIS methods. Different combinations of independent variables were examined to predict ash fusion temperatures in the multivariable procedure. The combination of the “11 oxides + (Base/Acid + Silica ratio” was the best predictor. Correlation coefficients (R2 of 0.891, 0.917, and 0.94 were achieved using nonlinear equations for the prediction of initial deformation temperature (IDT, softening temperature (ST, and fluid temperature (FT, respectively. The mentioned “best predictor” was used as input to the ANFIS system as well, and the correlation coefficients (R2 of the prediction were enhanced to 0.97, 0.98, and 0.99 for IDT, ST, and FT, respectively. The prediction precision that was achieved in this work exceeded that reported in previously published works.

  7. Coal blend combustion. Link between unburnt carbon in fly ashes and maceral composition

    Energy Technology Data Exchange (ETDEWEB)

    Helle, Sonia; Alfaro, Guillermo [Instituto de Geologia Economica Aplicada GEA, Universidad de Concepcion, P.O.B. 160-C, Casilla (Chile); Gordon, Alfredo; Garcia, Ximena; Ulloa, Claudia [Departamento de Ingenieria Quimica, Universidad de Concepcion, P.O.B. 160-C, Casilla (Chile)

    2003-03-15

    Coal blends are increasingly utilised at power plants with significant savings and without breaking environment regulations. However, evidence of interaction among the coals requires the study of some parameters that affect combustion efficiency and related opacity of emissions. Actual plant data was available for the combustion of five families of binary blends (single coals and approximately 25%/75%, 50%/50% and 75%/25% blends) with variable contents of ash, volatiles and maceral composition. Size distribution of particles was determined for the coals fed to the plant boilers and the fly ashes, as well as for unburnt carbon in the latter. The almost homogeneously sized feed from different coals generates a size distribution in the fly ash where 250-{mu}m particles vary up to 1.29%, while particles smaller than 38 {mu}m vary between 21.74% and 62.41%. Unburnt carbon increases with size of ash particles from a maximum of 12.2% for fractions smaller than 38 {mu}m up to 73.9% for the fraction bigger than 150 {mu}m. Total content of unburnt carbon in the fly ash from combustion of coal blends show deviations from the expected weighted average of the constituent coals (K, L, T, P, F, S and N). These deviations are related to maceral composition and rank based on reflectance values. The smallest deviation is shown by the blend (T/P) with coals having low values of reflectance and homogeneity of maceral contents. Larger deviations were found for blends K/L, P/F and S/N with higher difference of rank and greater heterogeneity of maceral composition. The K/L, R/N and S/N blends show positive deviations with respect to the expected weighted average, that is, blending was detrimental to the combustion efficiency, while blend P-F showed an enhance of the combustion efficiency as measured by unburnt carbon in the fly ash. A 'reactive maceral index' introduced in this work plays a useful role. If a ratio of reactive maceral index is established for a binary blend as

  8. M(o)ssbauer spectroscopic studies the characterization of three China coal and the corresponding fly-ashes and bottom ashes

    Institute of Scientific and Technical Information of China (English)

    YAO Duo-xi; ZHI Xia-chen

    2006-01-01

    Three fresh China coals (lignitie, bituminite and anthracite) from different geological origin and the corresponding fly and bottom ashes were studied by room temperature(RT) M(o)ssbauer spectroscopy(MS). The iron-bearing minerals were characterized to was found in bituminite and anthracite coal.The M(o)ssbauer spectra of the fly and bottom ashes as a result of pulverised coal combustion(PCC) in Xiaolongtan,Shuicheng and Luohuang Power Plants are comprised of superimposed sextets and doulets of oxides includes maghemite(γ-Fe2O3), magnitite(Fe3O4), haematite(α-Fe2O3), magnesioferite (MgFe2O4), Fe3+/Fe2+-mullite, Fe3+-glass silicate andmetallic iron. The studies also show that iron-bearing minerals in coals are largely dependant on geological regions and coal rank, the composition of the corresponding fly and bottom ashes will not only depend on the type and mineralogy of the feed coal but also on the local nature of combustion.

  9. Ash liberation from included minerals during combustion of pulverized coal: the relationship with char structure and burnout

    Energy Technology Data Exchange (ETDEWEB)

    Wu, H.; Wall, T.; Liu, G.; Bryant, G. [University of Newcastle, Callaghan, NSW (Australia). CRC for Black Coal Utilization and Dept. of Chemical Engineering

    1999-12-01

    In this study, the float fraction ({lt} specific gravity of 2.0) of a size cut (63-90 {mu}m) bituminous coal was combusted in a drop tube furnace (DTF) at a gas temperature of 1300{degree}C under an atmosphere of air, to investigate the ash liberation at five coal burnoff levels (35.5%, 54.3%, 70.1%, 87.1% and 95.6%). The data indicated that char structure determines the ash liberation at different burnoff levels. Fragmentation of porous char was found to be the determinative mechanism for formation of fine ash during the early and middle stages of char combustion, while coalescence of included mineral matter determines the coarse ash formed in the later stages of combustion. The investigation confirmed that the char morphology and structure play a key role in determining char fragmentation, char burnout history, and the ash liberation during combustion. 35 refs., 5 figs., 2 tabs.

  10. Melting Behavior of ashes from the co-combustion of coal and straw

    DEFF Research Database (Denmark)

    Arvelakis, Stelios; Frandsen, Flemming

    2007-01-01

    . The use of straw as a co-firing feedstock in traditional coal-fired plants is associated with operational problems, such as deposition, agglomeration, and/or corrosion, mainly because of the higher amounts of alkali metals and chlorine in straw compared to coal. This may lead to unscheduled shutdowns......Straw may be used today as a substitute fuel to lower the greenhouse gas emissions from traditional coalfired power plants and provide green-based electricity. It may also provide an alternative source of income to the local farmers helping the developed countries to support sustainable development...... and costly repairs, increasing the operational costs and the cost of the produced power. In this paper, the melting characteristics of several ash fractions sampled from different parts of a pilot-scale pulverized fuel (PF) boiler operating with different coal/straw mixtures is determined by measuring...

  11. Production of cements from Illinois coal ash. Technical report, September 1, 1995--November 30, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, J.C. [Institute of Gas Technology, Chicago, IL (United States); Bhatty, J.I.; Mishulovich, A. [Construction Technology Labs., Inc., Washington, DC (United States)

    1995-12-31

    The objective of this program is to convert Illinois coal combustion residues, such as fly ash, bottom ash, and boiler slag, into novel cementitious materials for use in the construction industry. Currently only about 30% of the 5 million tons of these coal combustion residues generated in Illinois each year are utilized, mainly as aggregate. These residues are composed largely Of SiO{sub 2}, Al{sub 2}O{sub 3}, Fe{sub 2}O{sub 3}, MgO, and CaO, which are also the major components of cement. The process being developed in this program will use the residues directly in the manufacture of cement products. Therefore, a much larger amount of residues can be utilized. To achieve the above objective, in the first phase (current year) samples of coal combustion residues will be blended and mixed, as needed, with a lime or cement kiln dust (CKD) to adjust the CaO composition. Six mixtures will be melted in a laboratory-scale furnace at CTL. The resulting products will then be tested for cementitious properties. Two preliminary blends have been tested. One blend used fly ash with limestone, while the other used fly ash with CKD. Each blend was melted and then quenched, and the resulting product samples were ground to a specific surface area similar to portland cement. Cementitious properties of these product samples were evaluated by compression testing of 1-inch cube specimens. The specimens were formed out of cement paste where a certain percentage of the cement paste is displaced by one of the sample products. The specimens were cured for 24 hours at 55{degrees}C and 100% relative humidity. The specimens made with the product samples obtained 84 and 89% of the strength of a pure portland cement control cube. For comparison, similar (pozzolanic) materials in standard concrete practice are required to have a compressive strength of at least 75% of that of the control.

  12. Distributional Fate of Elements during the Synthesis of Zeolites from South African Coal Fly Ash

    Directory of Open Access Journals (Sweden)

    Pieter W. Du Plessis

    2014-04-01

    Full Text Available The synthesis of zeolites from South African coal fly ash has been deemed a viable solution to the growing economical strain caused by the disposal of ash in the country. Two synthesis routes have been studied thus far namely the 2-step method and the fusion assisted process. Fly ash contains several elements originating from coal which is incorporated in the ash during combustion. It is vital to determine the final destination of these elements in order to unveil optimization opportunities for scale-up purposes. The aim of this study was to perform a material balance study on both synthesis routes to determine the distributional fate of these elements during the synthesis of zeolites. Zeolites were first synthesized by means of the two synthesis routes. The composition of all raw materials and products were determined after which an overall and elemental balance were performed. Results indicated that in the 2-step method almost all elements were concentrated in the solid zeolite product while during the fusion assisted route the elements mostly report to the solid waste. Toxic elements such as Pb, Hg, Al, As and Nb were found in both the supernatant waste and washing water resulting from each synthesis route. It has also been seen that large quantities of Si and Al are wasted in the supernatant waste. It is highly recommended that the opportunity to recycle this liquid waste be investigated for scale-up purposes. Results also indicate that efficiency whereby Si and Al are extracted from fused ash is exceptionally poor and should be optimized.

  13. Coal R & D Case study: utilisation of fly ash and desulphurisation residues

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-12-01

    A significant proportion of fly ash from coal-fired plant in Europe is currently used as a constituent of cements and mortars or for the manufacture of concrete and lightweight insulating materials. Similarly, a substantial amount of the gypsum produced from wet limestone and wet lime flue gas desulphurisation (FGD) processes employed in many coal-fired plant is used in the manufacture of cements, wallboards and other construction materials. Despite this, however, considerable quantities of fly ash, particularly that with a high carbon content, and desulphurisation residues, particularly non-gypsum ones, currently have no commercial applications. Disposal of these residues is costly and creates environmental problems. As a result, there is considerable interest in most European countries in developing processes for upgrading these residues into construction materials. Through a collaborative European initiate, a laboratory-scale process was developed to produce calcium sulphoaluminate (CSA) cements using high carbon content fly ash and FGD residues, particularly non-gypsum ones. Samples from a number of European coal-fired power plant were used in the development of this process. The cements produced look attractive for application as replacements for Ordinary Portland Cement (OPC), constituents of blended cement and constituents of ready mixed and pre-cast concretes. Further work is now required to optimise the process to manufacture CSA cements and to demonstrate them at pilot scale prior to commercialisation. Approaches have been made to power plant operators regarding the construction and trial operation of a pilot-scale CSA cement production facility at a European coal-fired power station. 3 figs., 3 tabs.

  14. Applied Technological Direction of Power Plant Ash and Slag Waste Management when Kuznetsk Bituminous Coal is Burned

    Directory of Open Access Journals (Sweden)

    Lihach Snejana A.

    2016-01-01

    Full Text Available Currently a lot of power plants have a problem with storage of coal combustion solid by-products (ash and slag. Holding capacity of existing power plants available ash dumps were enlarged and modernized repeatedly. Many plants have two or even three of them. Today new ash dump construction is economically inconvenient due to need to assign new plots of land and their inconveniently big distance from a plant, which increase ash and slag transportation expenses. The goal of our research work is to find promising directions for ash and slag waste mass utilization based on Kuznetsk bituminous coals experimental data on ultimate composition and properties. The experimental research of ash, slag and their mixture samples from ash dumps brought us to conclusion that the most promising direction for these materials application in large quantities is construction industry including road construction. Be-sides, we lined up some other directions for ash, slag, and ash and slag mixture possible application. These directions might not provide mass utilization but they are promising from a point of view of the researched waste properties.

  15. Ash fouling monitoring and key variables analysis for coal fired power plant boiler

    Directory of Open Access Journals (Sweden)

    Shi Yuanhao

    2015-01-01

    Full Text Available Ash deposition on heat transfer surfaces is still a significant problem in coal-fired power plant utility boilers. The effective ways to deal with this problem are accurate on-line monitoring of ash fouling and soot-blowing. In this paper, an online ash fouling monitoring model based on dynamic mass and energy balance method is developed and key variables analysis technique is introduced to study the internal behavior of soot-blowing system. In this process, artificial neural networks (ANN are used to optimize the boiler soot-blowing model and mean impact values method is utilized to determine a set of key variables. The validity of the models has been illustrated in a real case-study boiler, a 300MW Chinese power station. The results on same real plant data show that both models have good prediction accuracy, while the ANN model II has less input parameters. This work will be the basis of a future development in order to control and optimize the soot-blowing of the coal-fired power plant utility boilers.

  16. Frequency comparative study of coal-fired fly ash acoustic agglomeration

    Institute of Scientific and Technical Information of China (English)

    Jianzhong Liu; Jie Wang; Guangxue Zhang; Junhu Zhou; Kefa Cen

    2011-01-01

    Particulate pollution is main kind of atmospheric pollution.The fine particles are seriously harmful to human health and environment.Acoustic agglomeration is considered as a promising pretreatment technology for fine particle agglomeration.The mechanisms of acoustic agglomeration are very complex and the agglomeration efficiency is affected by many factors.The most important and controversial factor is frequency.Comparative studies between high-frequency and low-frequency sound source to agglomerate coalfired fly ash were carried out to investigate the influence of frequency on agglomeration efficiency.Acoustic agglomeration theoretical analysis,experimental particle size distributions (PSDs) and orthogonal design were examined.The results showed that the 20 kHz high-frequency sound source was not suitable to agglomerate coal-fired fly ash.Only within the size ranging from 0.2 to 0.25 μm the particles agglomerated to adhere together,and the agglomerated particles were smaller than 2.5 μm.The application of low-frequency (1000-1800 Hz) sound source was proved as an advisable pretreatment with the highest agglomeration efficiency of 75.3%,and all the number concentrations within the measuring range decreased.Orthogonal design L16 (4)3 was introduced to determine the optimum frequency and optimize acoustic agglomeration condition.According to the results of orthogonal analysis,frequency was the dominant factor of coal-fired fly ash acoustic agglomeration and the optimum frequency was 1400 Hz.

  17. Improving lithium-ion battery performances by adding fly ash from coal combustion on cathode film

    Energy Technology Data Exchange (ETDEWEB)

    Dyartanti, Endah Retno; Jumari, Arif, E-mail: arifjumari@yahoo.com; Nur, Adrian; Purwanto, Agus [Research Group of Battery & Advanced Material, Department of Chemical Engineering, Sebelas Maret University, Jl. Ir. Sutami 36 A Kentingan, Surakarta Indonesia 57126 (Indonesia)

    2016-02-08

    A lithium battery is composed of anode, cathode and a separator. The performance of lithium battery is also influenced by the conductive material of cathode film. In this research, the use of fly ash from coal combustion as conductive enhancer for increasing the performances of lithium battery was investigated. Lithium iron phosphate (LiFePO{sub 4}) was used as the active material of cathode. The dry fly ash passed through 200 mesh screen, LiFePO{sub 4} and acethylene black (AB), polyvinylidene fluoride (PVDF) as a binder and N-methyl-2-pyrrolidone (NMP) as a solvent were mixed to form slurry. The slurry was then coated, dried and hot pressed to obtain the cathode film. The ratio of fly ash and AB were varied at the values of 1%, 2%, 3%, 4% and 5% while the other components were at constant. The anode film was casted with certain thickness and composition. The performance of battery lithium was examined by Eight Channel Battery Analyzer, the composition of the cathode film was examined by XRD (X-Ray Diffraction), and the structure and morphology of the anode film was analyzed by SEM (Scanning Electron Microscope). The composition, structure and morphology of cathode film was only different when fly ash added was 4% of AB or more. The addition of 2% of AB on cathode film gave the best performance of 81.712 mAh/g on charging and 79.412 mAh/g on discharging.

  18. Improving lithium-ion battery performances by adding fly ash from coal combustion on cathode film

    International Nuclear Information System (INIS)

    A lithium battery is composed of anode, cathode and a separator. The performance of lithium battery is also influenced by the conductive material of cathode film. In this research, the use of fly ash from coal combustion as conductive enhancer for increasing the performances of lithium battery was investigated. Lithium iron phosphate (LiFePO4) was used as the active material of cathode. The dry fly ash passed through 200 mesh screen, LiFePO4 and acethylene black (AB), polyvinylidene fluoride (PVDF) as a binder and N-methyl-2-pyrrolidone (NMP) as a solvent were mixed to form slurry. The slurry was then coated, dried and hot pressed to obtain the cathode film. The ratio of fly ash and AB were varied at the values of 1%, 2%, 3%, 4% and 5% while the other components were at constant. The anode film was casted with certain thickness and composition. The performance of battery lithium was examined by Eight Channel Battery Analyzer, the composition of the cathode film was examined by XRD (X-Ray Diffraction), and the structure and morphology of the anode film was analyzed by SEM (Scanning Electron Microscope). The composition, structure and morphology of cathode film was only different when fly ash added was 4% of AB or more. The addition of 2% of AB on cathode film gave the best performance of 81.712 mAh/g on charging and 79.412 mAh/g on discharging

  19. Improving lithium-ion battery performances by adding fly ash from coal combustion on cathode film

    Science.gov (United States)

    Dyartanti, Endah Retno; Jumari, Arif; Nur, Adrian; Purwanto, Agus

    2016-02-01

    A lithium battery is composed of anode, cathode and a separator. The performance of lithium battery is also influenced by the conductive material of cathode film. In this research, the use of fly ash from coal combustion as conductive enhancer for increasing the performances of lithium battery was investigated. Lithium iron phosphate (LiFePO4) was used as the active material of cathode. The dry fly ash passed through 200 mesh screen, LiFePO4 and acethylene black (AB), polyvinylidene fluoride (PVDF) as a binder and N-methyl-2-pyrrolidone (NMP) as a solvent were mixed to form slurry. The slurry was then coated, dried and hot pressed to obtain the cathode film. The ratio of fly ash and AB were varied at the values of 1%, 2%, 3%, 4% and 5% while the other components were at constant. The anode film was casted with certain thickness and composition. The performance of battery lithium was examined by Eight Channel Battery Analyzer, the composition of the cathode film was examined by XRD (X-Ray Diffraction), and the structure and morphology of the anode film was analyzed by SEM (Scanning Electron Microscope). The composition, structure and morphology of cathode film was only different when fly ash added was 4% of AB or more. The addition of 2% of AB on cathode film gave the best performance of 81.712 mAh/g on charging and 79.412 mAh/g on discharging.

  20. Measurement of uranium and thorium in coal fly ash and bottom ash samples from a thermal power plant by using a high resolution semiconductor detector

    International Nuclear Information System (INIS)

    A low background γ-ray detection system has been constructed for measuring the natural radioactivity in coal samples. It is based on a high-purity Ge detector mounted within a massive lead shield which reduces the normal background level by a factor of about 20. This makes it possible to measure the low intensity γ-rays from the natural radioactivity present in the samples. Using this equipment uranium and thorium concentrations in coal fly ash and bottom ash samples from a coal fired power plant located at Bathinda, India have been measured. The uranium activity found in the samples is within the range of concentrations observed in other countries while the thorium activity is found to be somewhat higher. (Author)

  1. An introductory TEM study of Fe-nanominerals within coal fly ash

    International Nuclear Information System (INIS)

    The investigation presented here was conducted during a wider experiment on the technical feasibility and environmental impacts of tire combustion in a Brazilian coal-fired power station. Nanometric-sized crystalline phases in fly ash were characterised using energy-dispersive X-ray spectrometer (EDS) and high-resolution transmission electron microscopy (HR-TEM) images. The nanoparticles, which register abundance peaks at 10 nm and 100 nm, include iron-rich oxide (e.g. hematite), Fe-sulphate (e.g., yavapaiite: KFe(SO4)2), and Fe-aluminumsilicate glass. Individual metalliferous nanoparticles have a heterogeneous microstructure in which elements such as iron, aluminum and silicon are not uniformly distributed. HR-TEM offers a powerful analytical technique in the study of fly ash nanoparticles, providing a better understanding of the detailed chemistry of this potentially strongly bioreactive component of atmospheric particulate matter.

  2. Growth responses of selected freshwater algae to trace elements and scrubber ash slurry generated by coal-fired power plants

    Energy Technology Data Exchange (ETDEWEB)

    Vocke, R.W.

    1979-01-01

    The development and implementation of standard toxicity tests is a necessity if consistent and reliable data are to be obtained for water quality criteria. The adapted EPA AAPBT is an ideal static algal toxicity test system. The algal test medium has a chemical composition similar to natural unpolluted waters of low ionic strength. It is appropriate to use MATC water quality criteria when assessing the potential impact of pollutants generated by coal-fired power stations because these energy-generated pollutants typically enter aquatic systems in small quantities over long periods. The MATC water quality criteria are estimates of trace element and SASE levels, based on the most sensitive alga investigated, that will not cause significant changes in naturally-functioning algal populations. These levels are 0.016f mg L/sup -1/ As(V), 0.001 mg L/sup -1/ Cd(II), 0.004 mg L/sup -1/ Hg(II), 0.006 mg L/sup -1/ Se(VI), and 0.344% SASE. To provide viable working water quality criteria, an extrapolation from the laboratory to the natural environment must be made. Therefore, those oxidation states of the trace elements were selected which are the dominant states occurring in natural, unpolluted, slightly alkaline freshwaters. It must be pointed out that these MATC values are based on algal responses to single toxicants and no allowance is made for synergistic, additive, or antagonistic relationships which could occur in natural aquatic systems. Additionally, natural chelation may influence toxicity. The highly toxic nature of potential pollutants from coal-fired generating plants emphasizes the need for minimizing stack effluent pollutants and retaining scrubber ash slurry for proper disposal in an effort to maintain trace elements in concentration ranges compatible with naturally-functioning ecosystems.

  3. Ash removal equipment of large power plants designed for increased brown coal ash content and for economic use of waste products

    Energy Technology Data Exchange (ETDEWEB)

    Neumann, G.; Nicko, K.H.; Weidlich, H.G.

    1984-12-01

    The design and performance of the pneumatic deashing system of a brown coal fired steam generator with 660 t/h steam capacity are explained. Experiments were carried out aimed at improving the performance of the pneumatic conveyor with its discontinuously working pressure vessel. A modified technology of operating the pneumatic system quasi-continuously was investigated, with which a 100% higher ash throughput, elimination of pipe clogging and a 40% reduction in air requirement were achieved. Equipment for loading ash from bunkers into closed container cars was further studied. Substantial steel wear was noted at the mixing screw of the ash moistening trough. A new ash moistening and mixing drum (4 m long, 1.8 m diameter, 20 kW drive) has been developed, capable of moistening 600 m/sup 3//h of ash with only 15% of the electrical energy and 30% of the maintenance expenditures of mixing screw equipment. The manufacturer, OBV Budapest, will produce 3 sizes of the new ash mixing drum for reconstruction of ash loading facilities at various power plants. 7 references.

  4. Environmental, physical and structural characterisation of geopolymer matrixes synthesised from coal (co-)combustion fly ashes.

    Science.gov (United States)

    Alvarez-Ayuso, E; Querol, X; Plana, F; Alastuey, A; Moreno, N; Izquierdo, M; Font, O; Moreno, T; Diez, S; Vázquez, E; Barra, M

    2008-06-15

    The synthesis of geopolymer matrixes from coal (co-)combustion fly ashes as the sole source of silica and alumina has been studied in order to assess both their capacity to immobilise the potentially toxic elements contained in these coal (co-)combustion by-products and their suitability to be used as cement replacements. The geopolymerisation process has been performed using (5, 8 and 12 M) NaOH solutions as activation media and different curing time (6-48 h) and temperature (40-80 degrees C) conditions. Synthesised geopolymers have been characterised with regard to their leaching behaviour, following the DIN 38414-S4 [DIN 38414-S4, Determination of leachability by water (S4), group S: sludge and sediments. German standard methods for the examination of water, waste water and sludge. Institut für Normung, Berlin, 1984] and NEN 7375 [NEN 7375, Leaching characteristics of moulded or monolithic building and waste materials. Determination of leaching of inorganic components with the diffusion test. Netherlands Normalisation Institute, Delft, 2004] procedures, and to their structural stability by means of compressive strength measurements. In addition, geopolymer mineralogy, morphology and structure have been studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), respectively. It was found that synthesised geopolymer matrixes were only effective in the chemical immobilisation of a number of elements of environmental concern contained in fly ashes, reducing (especially for Ba), or maintaining their leachable contents after the geopolymerisation process, but not for those elements present as oxyanions. Physical entrapment does not seem either to contribute in an important way, in general, to the immobilisation of oxyanions. The structural stability of synthesised geopolymers was mainly dependent on the glass content of fly ashes, attaining at the optimal activation conditions (12 M NaOH, 48 h, 80

  5. Performance of coal fly-ash based oxygen carrier for the chemical looping combustion of synthesis gas

    International Nuclear Information System (INIS)

    Highlights: • Fly-ash based oxygen carriers were synthesised for chemical looping combustion of synthesis gas. • Using fly-ash as the support of the oxygen carrier enhanced the thermal stability and oxidant transfer for fuel oxidation. • Fly-ash based nickel oxide reformed hydrocarbons into carbon monoxide with the presence of carbon dioxide. - Abstract: The performance of coal fly-ash based oxygen carriers for chemical looping combustion of synthesis gas has been investigated using both a thermogravimetric analyser and a packed bed reactor. Oxygen carriers with 50 wt% active metal compounds, including copper, nickel and iron oxides, supported on coal fly-ash were synthesised using the deposition–precipitation method. Copper oxide and nickel oxide supported on fly-ash showed high oxygen transfer efficiency and oxygen carrying capacity at 800 °C. The fly-ash based nickel oxide was effective in reforming hydrocarbons and for the conversion of carbon dioxide into carbon monoxide; a nickel complex with silicate was identified as a minor phase following the reduction reaction. The fly-ash based iron oxide showed various reduction steps and resulted in an extended reduction time. The carbon emission at the oxidation stage was avoided by reducing the length of the exposure to the reduction gas

  6. Radiological characterization of the coal ash and slag from Kastel Gomilica, Croatia

    Energy Technology Data Exchange (ETDEWEB)

    Lovrencic, I.; Orescanin, V.; Barisic, D.; Mikelic, L.; Rozmaric Macefat, M.; Lulic, St. [Rudjer Boskovic Institute, Zagreb (Croatia); Pavlovic, G. [Zagreb Univ., Faculty of Science, Dept. of Mineralogy and Petrography (Croatia)

    2006-07-01

    objective of this study was radiological characterization of slag and ash produced in a thermo electric unit of the former 'Adriavinil' chemical factory as a by-product of coal combustion and deposited in the Kastel Gomilica region, Croatia. The waste material was deposited in the 'old' regulated and the 'new' unregulated part of the depot. 33 samples were analyzed to obtain a preliminary data on the present state of the new unregulated part of the depot. Activities of the selected radionuclides (40 K, 232 Th, 235 U and 226 Ra) were measured using gamma-spectrometry method. 238 U activity was calculated from the assumed natural 235 U /238 U activity ratio. It is found that there is a dependence of the activities of the selected radionuclides on the activities of the coal used for energy production in the power unit. The content of 232 Th, 226 Ra and 238 U in slag and ash increased several times during the combustion process. Investigated slag and ash showed a significant variability in their activities of selected radionuclides due to a different origin of coal used in the thermoelectric unit of the factory. The waste material was characterized by high activity of naturally occurring 238 U, 235 U and 226 Ra. 226 Ra and 238 U activities were up to 50 times higher than their average activities characteristic for surrounding soils developed on flysch sediments. 40 K and 232 Th showed no elevation compared to soil activities. Mineralogical analysis has been made as well. (authors)

  7. Characteristics of fly ashes from full-scale coal-fired power plants and their relationship to mercury adsorption

    Science.gov (United States)

    Lu, Y.; Rostam-Abadi, M.; Chang, R.; Richardson, C.; Paradis, J.

    2007-01-01

    Nine fly ash samples were collected from the particulate collection devices (baghouse or electrostatic precipitator) of four full-scale pulverized coal (PC) utility boilers burning eastern bituminous coals (EB-PC ashes) and three cyclone utility boilers burning either Powder River Basin (PRB) coals or PRB blends,(PRB-CYC ashes). As-received fly ash samples were mechanically sieved to obtain six size fractions. Unburned carbon (UBC) content, mercury content, and Brunauer-Emmett-Teller (BET)-N2 surface areas of as-received fly ashes and their size fractions were measured. In addition, UBC particles were examined by scanning electron microscopy, high-resolution transmission microscopy, and thermogravimetry to obtain information on their surface morphology, structure, and oxidation reactivity. It was found that the UBC particles contained amorphous carbon, ribbon-shaped graphitic carbon, and highly ordered graphite structures. The mercury contents of the UBCs (Hg/UBC, in ppm) in raw ash samples were comparable to those of the UBC-enriched samples, indicating that mercury was mainly adsorbed on the UBC in fly ash. The UBC content decreased with a decreasing particle size range for all nine ashes. There was no correlation between the mercury and UBC contents of different size fractions of as-received ashes. The mercury content of the UBCs in each size fraction, however, generally increased with a decreasing particle size for the nine ashes. The mercury contents and surface areas of the UBCs in the PRB-CYC ashes were about 8 and 3 times higher than UBCs in the EB-PC ashes, respectively. It appeared that both the particle size and surface area of UBC could contribute to mercury capture. The particle size of the UBC in PRB-CYC ash and thus the external mass transfer was found to be the major factor impacting the mercury adsorption. Both the particle size and surface reactivity of the UBC in EB-PC ash, which generally had a lower carbon oxidation reactivity than the PRB

  8. Development of Natural Alkalinity in Appalachian Deep Coal Mine Discharges, Irwin Syncline, Pennsylvania, USA

    Science.gov (United States)

    Bryant, E. M.; Winters, W. R.; Winters, W. R.; Capo, R. C.

    2001-12-01

    Geochemical processes in flooded underground coal mine complexes are controlled by the relationship between overburden mineralogy and the hydrogeologic system, which is influenced by mining methodology and discharge location. Numerous large flow (over 2,000 L/min), historically acidic, deep mine discharges in Appalachian bituminous coal basins are now net alkaline, with circumneutral pH and high concentrations of dissolved iron (20-80 ppm) and sodium (100-500 ppm) [1]. Understanding natural alkalinity production offers alternative approaches for neutralizing acid mine drainage (AMD) and has implications for predictive models, mining regulations, mine discharge remediation, and resource recovery. To determine the subsurface processes involved in the generation of natural alkalinity, we focused on the Irwin syncline, a 240 sq.-km bituminous coal basin in southwestern Pennsylvania. All major streams that arise within or cross the syncline are affected by polluted mine drainage. The pollution ranges from highly acidic iron- and aluminum-contaminated discharges in the northern portion of the basin to highly alkaline, iron and sulfate-contaminated discharges in the southern portion. Underground mine barrier data were used to divide the basin into six hydraulically related sub-basins; mine waters were collected from nine discharges across the basin [2]. Sub-basin hydrology was integrated with infiltration, discharge, and overburden geochemistry and mineralogy. Modeling of Irwin syncline flows using a solute modeling program (PHREEQC 2.4.2; [3]) indicates that the spatial and temporal change in mine water chemistry involves processes other than simple carbonate dissolution or dilution with uncontaminated water. Results indicate that the acidic discharges in the northeastern end of the basin are the product of surface water modified by pyrite oxidation and dissolution of aluminosilicate minerals. Sodium concentrations in those flows are likely the result of minor halite

  9. Use of coal ash for enhancing biocrust development in stabilizing sand dunes

    Science.gov (United States)

    Zaady, Eli; Katra, Itzhak; Sarig, Shlomo

    2015-04-01

    In dryland environments, biocrusts are considered ecosystem engineers since they play significant roles in ecosystem processes. In the successional pathway of crust communities, the new areas are colonized after disturbance by pioneers such as filamentous cyanobacteria - Microcoleus spp. This stage is followed by colonization of green algae, mosses, and lichens. Aggregation of soil granules is caused by metabolic polysaccharides secreted by cyanobacteria and green algae, gluing the soil particles to form the crust layer. It was suggested that incorporating dust into the biocrusts encourages the growth of cyanobacteria, leading to a strengthening of the biocrusts' cohesion. Moreover, biocrusts cover a larger portion of the surface when the soil contains finer particles, and it was observed that at least 4-5% of clay and silt is required to support a measurable biocrust. While natural and undisturbed sand dunes are generally stabilized by biocrusts in the north-western Negev desert, stabilization of disturbed and movable sand dunes is one of the main problems in this desertified land, as in vast areas in the world. Daily breezes and seasonal wind storms transport sand particles to populated and agricultural areas causing damages to field crops and livelihood. Moving sand dunes consist of relatively coarse grains (250-2000 μm) with a low percent of clay and silt. This phenomenon negatively affects cyanobacterial colonization rate, even in relatively wet desert areas (100-250 mm rainfalls). In order to face the problem it was suggested to enrich the dune surface by using coal fly-ash. The research was conducted in two stages: first, examining the feasibility in Petri-dishes in laboratory conditions and in Experimental Aeolian Greenhouse conditions. The results showed that adding coal fly-ash and biocrust inoculum increased aggregate stability, penetration resistance and shear strength, as opposed to the control-sand plot. Using mobile wind-tunnel simulations, sand

  10. Extraction of Alumina from Coal Fly Ash with Sulfuric Acid Leaching Method

    Institute of Scientific and Technical Information of China (English)

    李来时; 吴玉胜; 刘瑛瑛; 翟玉春

    2011-01-01

    Coarse γ-Al2O3 powder was prepared through acid leaching, solid-liquid separation, crystallizing and aluminum sulfate decomposing processes using coal fly ash and concentrated sulfuric acid as raw materials. The metallurgy level Al2O3 can be obtained by disposing coarse γ-Al2O3 powder with Bayer process. The optimum conditions of acid leaching process were determined by experiments. The extraction rate of Al2O3 can be stabilized at about 87% under these conditions. The thermodynamics and kinetics of sulfuric acid leaching process were studied with irreversible thermodynamics.

  11. Physical Parameters Affecting the Emanation of RADON-222 from Coal Ash.

    Science.gov (United States)

    Barton, Terence Patrick

    The Rn-222 emanation coefficients for coal ash and parameters which affected them were measured. Samples of ash from both stoker fired and pulverized coal fired boilers were obtained. The stoker ash samples were mechanically separated into size fractions. The pulverized samples were too fine for mechanical sizing and were categorized qualitatively according to origin. Bulk density of the stoker fractions was measured and ranged from .488 to .944 g-cm('-3), increasing as a function of decreasing particle size. Bulk density of the pulverized ash ranged from 1.254 to 1.520 g-cm('-3). Specific gravity of the stoker fractions ranged from 2.017 to 2.390 g-cm('-3), also increasing as a function of decreasing particle size. Specific gravity of the pulverized ash ranged from 2.357 to 2.588 g-cm(' -3). Ra-226 content of the samples was determined by gamma spectrometric analysis of the 352-KeV gamma of Pb -214 and the 609-KeV gamma of Bi-214 from sealed samples of ash. Ra-226 concentrations in the stoker fractions ranged from 11.82 to 16.77 dpm-g('-1), increasing as a function of decreasing particle size. Ra-226 concentrations in the pulverized ash ranged from 6.44 to 7.59 dpm-g(' -1). Scintillation cells were constructed out of commonly available materials and a commercial preparation of ZnS(Ag) scintillator. Emanation chambers which allowed for moderately large sample masses were constructed. The procedure used to measure emanation coefficients was shown to be insensitive to ingrowth time at greater than 3 days ingrowth and relatively insensitive to variations in sample porosity. Emanation coefficients of the stoker fractions were measured at moisture contents of 0, 1.0, 10, 20, and 40 percent by weight. Within each size fraction the emanation coefficient increased as a function of moisture content, ranging from 9.58 x 10('-4) to 4.13 x 10('-2) between 0 and 20 percent moisture, respectively. Emanation coefficients also increased as a function of decreasing particle size

  12. Removal of vertigo blue dyes from Batik textile wastewater by adsorption onto activated carbon and coal bottom ash

    Science.gov (United States)

    Kusmiyati, L., Puspita Adi; Deni, V.; Robi Indra, S.; Islamica, Dlia; Fuadi, M.

    2016-04-01

    Removal of vertigo blue dye from batik textile wastewater was studied by adsorptionprocess onto activated carbon (AC) and coal bottom ash (CBA).The influence of experimental conditions (pH solution, dye concentration, and contact time) were studied on the both adsorbents. At equilibrium conditions, the data were fitted to Langmuir and Freundlich adsorption models. The maximum adsorption capacity calculated from the Langmuir model for carbon active was 6.29mg/g at pH that found to be considerably higher than that obtained for coal bottom ash 3.72mg/g pH 9. From Freundlich model, the maximum adsorption capacity is less for coal bottom ash (pH 9) than that for carbon active (pH4).

  13. Utilizing acid mine drainage sludge and coal fly ash for phosphate removal from dairy wastewater.

    Science.gov (United States)

    Wang, Y R; Tsang, Daniel C W; Olds, William E; Weber, Paul A

    2013-01-01

    This study aims to investigate a new and sustainable approach for the reuse of industrial by-products from wastewater treatment. The dairy industry produces huge volumes of wastewater, characterized by high levels of phosphate that can result in eutrophication and degradation of aquatic ecosystems. This study evaluated the application of acid mine drainage (AMD) sludge, coal fly ash, and lignite as low-cost adsorbents for the removal of phosphate from dairy wastewater. Material characterization using X-ray fluorescence, X-ray diffraction, and Brunauer-Emmett-Teller surface area analysis revealed significant amounts of crystalline/amorphous Fe/Al/Si/Ca-based minerals and large surface areas of AMD sludge and fly ash. Batch adsorption isotherms were best described using the Freundlich model. The Freundlich distribution coefficients were 13.7 mg(0.577) L(0.423) g(-1) and 16.9 mg(0.478) L(0.522) g(-1) for AMD sludge and fly ash, respectively, and the nonlinearity constants suggested favourable adsorption for column applications. The breakthrough curves of fixed-bed columns, containing greater than 10 wt% of the waste materials (individual or composite blends) mixed with sand, indicated that phosphate breakthrough did not occur within 100 pore volumes while the cumulative removal was 522 and 490 mg kg(-1) at 10 wt% AMD sludge and 10 wt% fly ash, respectively. By contrast, lignite exhibited negligible phosphate adsorption, possibly due to small amounts of inorganic minerals suitable for phosphate complexation and limited surface area. The results suggest that both AMD sludge and fly ash were potentially effective adsorbents if employed individually at a ratio of 10 wt% or above for column application. PMID:24617077

  14. Impact of coal fly ash addition on ash transformation and deposition in a full-scale wood suspension-firing boiler

    DEFF Research Database (Denmark)

    Wu, Hao; Bashir, Muhammad Shafique; Jensen, Peter Arendt;

    2013-01-01

    at the location with high flue gas temperatures was characterized by a slow and continuous growth of deposits followed by the shedding of a large layer of deposits, while at the location with low flue gas temperature the deposit formation started with a slow build-up and the amount of deposits became almost...... of the deposits. Overall, the results from this work suggest that coal fly ash can be an effective additive to minimize the possible ash deposition and corrosion problems during suspension-firing of wood. © 2013 Elsevier Ltd. All rights reserved....

  15. Synthesis of merlinoite from Chinese coal fly ashes and its potential utilization as slow release K-fertilizer.

    Science.gov (United States)

    Li, Jing; Zhuang, Xinguo; Font, Oriol; Moreno, Natalia; Vallejo, V Ramon; Querol, Xavier; Tobias, Aurelio

    2014-01-30

    This study focuses on the synthesis of merlinoite from Chinese coal fly ashes by KOH direct conversion method, with special emphasis on the application of synthetic merlinoite as fertilizer. These fly ashes were collected from two pulverized-coal combustion (PCC) power plants in Xinjiang, Northwest China. The synthesis results are influenced by fly ash characteristics and different synthesis conditions (KOH solution concentrations, activation temperature, time, and KOH/fly ash ratios). A high quality merlinoite-rich product was synthesized under optimal activation conditions (KOH concentration of 5M, activation temperature of 150°C, activation time of 8h and KOH/fly ash ratio of 2l/kg), with a cation exchange capacity (CEC) of 160cmolkg(-1). The synthetic merlinoite is proved to be an efficient slow release K-fertilizer for plant growth, indicating that it can be widely used for high-nutrient demanding crops growing in nutrient-limited soils and for large-area poor soil amendment in opencast coal mine areas around the power plants that will substantially grow with the increasing coal combustion in Xinjiang in the near future. PMID:24365875

  16. Method for increasing -SiC yield on solid state reaction of coal fly ash and activated carbon powder

    Indian Academy of Sciences (India)

    Sulardjaka; Jamasri; M W Wildan; Kusnanto

    2011-07-01

    A novel process for increasing -SiC yield on solid state reaction of coal fly ash and micro powder activated carbon powder has been proposed. -SiC powder was synthesized at temperature 1300°C for 2 h under vacuum condition with 1 l/min argon flow. Cycling synthesis process has been developed for increasing -SiC yield on solid state reaction of coal fly ash and activated carbon powder. Synthesized products were analyzed by XRD with Cu-K radiation, FTIR spectrometer and SEM fitted with EDAX. The results show that the amount of relative -SiC is increased with the number of cycling synthesis.

  17. pH-dependent leaching of constituents of potential concern from concrete materials containing coal combustion fly ash.

    Science.gov (United States)

    Kosson, David S; Garrabrants, Andrew C; DeLapp, Rossane; van der Sloot, Hans A

    2014-05-01

    Current concerns about the environmental safety of coal combustion fly ash have motivated this evaluation of the impact of fly ash use as a cement replacement in concrete materials on the leaching of constituents of potential concern. The chemical effects of fly ash on leaching were determined through characterization of liquid-solid partitioning using EPA Method 1313 for four fly ash materials as well as concrete and microconcrete materials containing 0% (control materials), 25% and 45% replacement of portland cement with the fly ash source. All source materials, concrete formulations and replacement levels are representative of US concrete industry practices. Eluate concentrations as a function of pH were compared to a broader range of available testing results for international concretes and mortars for which the leaching characteristics of the component fly ashes were unknown. The chemistry of the hydrated cement fraction was found to dominate the liquid-solid partitioning resulting in reduced leaching concentrations of most trace metals compared to concentrations from fly ash materials alone. Compared to controls, eluate concentrations of Sb, As, B, Cr, Mo, Se, Tl and V from concrete products containing fly ash were essentially the same as the eluate concentrations from control materials produced without fly ash replacement indicating little to no significant impact on aqueous partitioning.

  18. Diversity and activity of methanotrophs in alkaline soil from a Chinese coal mine

    Energy Technology Data Exchange (ETDEWEB)

    Han, Bing; Chen, Yin; Abell, Guy; Jiang, Hao; Bodrossy, Levente; Zhao, Jiangang; Murrell, J. Colin; Xing, Xin-Hui [Tsinghua University, Beijing (China). Dept. of Chemical Engineering

    2009-11-15

    Culture-independent molecular biological techniques, including 16S rRNA gene and functional gene clone libraries and microarray analyses using pmoA (encoding a key subunit of particulate methane monooxygenase), were applied to investigate the methanotroph community structure in alkaline soil from a Chinese coal mine. This environment contained a high diversity of methanotrophs, including the type II methanotrophs Methylosinus/Methylocystis, type I methanotrophs related to Methylobacter/Methylosoma and Methylococcus, and a number of as yet uncultivated methanotrophs. In order to identify the metabolically active methane-oxidizing bacteria from this alkaline environment, DNA stable isotope probing (DNA-SIP) experiments using {sup 13}CH{sub 4} were carried out. This showed that both type I and type II methanotrophs were active, together with methanotrophs related to Methylocella, which had previously been found only in acidic environments. Methylotrophs, including Methylopila and Hyphomicrobium, were also detected in soil DNA and after DNA-SIP experiments. DNA sequence information on the most abundant, active methanotrophs in this alkaline soil will facilitate the design of oligonucleotide probes to monitor enrichment cultures when isolating key alkaliphilic methanotrophs from such environments.

  19. The chemical composition of tertiary Indian coal ash and its combustion behaviour - a statistical approach: Part 2

    Science.gov (United States)

    Sharma, Arpita; Saikia, Ananya; Khare, Puja; Dutta, D. K.; Baruah, B. P.

    2014-08-01

    In Part 1 of the present investigation, 37 representative Eocene coal samples of Meghalaya, India were analyzed and their physico-chemical characteristics and the major oxides and minerals present in ash samples were studied for assessing the genesis of these coals. Various statistical tools were also applied to study their genesis. The datasets from Part 1 used in this investigation (Part 2) show the contribution of major oxides towards ash fusion temperatures (AFTs). The regression analysis of high temperature ash (HTA) composition and initial deformation temperature (IDT) show a definite increasing or decreasing trend, which has been used to determine the predictive indices for slagging, fouling, and abrasion propensities during combustion practices. The increase or decrease of IDT is influenced by the increase of Fe2O3, Al2O3, SiO2, and CaO, respectively. Detrital-authigenic index (DAI) calculated from the ash composition and its relation with AFT indicates Sialoferric nature of these coals. The correlation analysis, Principal Component Analysis (PCA), and Hierarchical Cluster Analysis (HCA) were used to study the possible fouling, slagging, and abrasion potentials in boilers during the coal combustion processes. A positive relationship between slagging and heating values of the coal has been found in this study.

  20. Survey of the potential environmental and health impacts in the immediate aftermath of the coal ash spill in Kingston, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    Laura Ruhl; Avner Vengosh; Gary S. Dwyer; Heileen Hsu-Kim; Amrika Deonarine; Mike Bergin; Julia Kravchenko [Duke University, Durham, NC (United States). Division of Earth and Ocean Sciences

    2009-08-15

    An investigation of the potential environmental and health impacts in the immediate aftermath of one of the largest coal ash spills in U.S. history at the Tennessee Valley Authority (TVA) Kingston coal-burning power plant has revealed three major findings. First, the surface release of coal ash with high levels of toxic elements (As = 75 mg/kg; Hg = 150 {mu}g/kg) and radioactivity ({sup 226}Ra + {sup 228}Ra = 8 pCi/g) to the environment has the potential to generate resuspended ambient fine particles (<10 {mu}m) containing these toxics into the atmosphere that may pose a health risk to local communities. Second, leaching of contaminants from the coal ash caused contamination of surface waters in areas of restricted water exchange, but only trace levels were found in the downstream Emory and Clinch Rivers due to river dilution. Third, the accumulation of Hg- and As-rich coal ash in river sediments has the potential to have an impact on the ecological system in the downstream rivers by fish poisoning and methylmercury formation in anaerobic river sediments. 61 refs., 2 figs., 3 tabs.

  1. The chemical composition of tertiary Indian coal ash and its combustion behaviour – a statistical approach: Part 2

    Indian Academy of Sciences (India)

    Arpita Sharma; Ananya Saikia; Puja Khare; D K Dutta; B P Baruah

    2014-08-01

    In Part 1 of the present investigation, 37 representative Eocene coal samples of Meghalaya, India were analyzed and their physico-chemical characteristics and the major oxides and minerals present in ash samples were studied for assessing the genesis of these coals. Various statistical tools were also applied to study their genesis. The datasets from Part 1 used in this investigation (Part 2) show the contribution of major oxides towards ash fusion temperatures (AFTs). The regression analysis of high temperature ash (HTA) composition and initial deformation temperature (IDT) show a definite increasing or decreasing trend, which has been used to determine the predictive indices for slagging, fouling, and abrasion propensities during combustion practices. The increase or decrease of IDT is influenced by the increase of Fe2O3, Al2O3, SiO2, and CaO, respectively. Detrital-authigenic index (DAI) calculated from the ash composition and its relation with AFT indicates Sialoferric nature of these coals. The correlation analysis, Principal Component Analysis (PCA), and Hierarchical Cluster Analysis (HCA) were used to study the possible fouling, slagging, and abrasion potentials in boilers during the coal combustion processes. A positive relationship between slagging and heating values of the coal has been found in this study.

  2. Size distributions of major elements in residual ash particles from coal combustion

    Institute of Scientific and Technical Information of China (English)

    YU DunXi; XU MingHou; YAO Hong; LIU XiaoWei

    2009-01-01

    Combustion experiments for three coals of different ranks were conducted in an electrically-heated drop tube furnace. The size distributions of major elements in the residual ash particles (>0.4μm) such as AI, Si, S, P, Na, Mg, K, Ca and Fe were investigated. The experimental results showed that the concentrations of AI and Si in the residual ash particles decreased with decreasing particle size, while the concentrations of S and P increased with decreasing particle size. No consistent size distributions were obtained for Na, Mg, K, Ca and Fe. The established deposition model accounting for trace element distributions was demonstrated to be applicable to some major elements as well. The modeling results indicated that the size distributions of the refractory elements, AI and Si, were mainly influenced by the deposition of vaporized elements on particle surfaces. A dominant fraction of S and P vaporized during coal combustion. Their size distributions were determined by surface condensation, reaction or adsorption. The partitioning mechanisms of Na, Mg, K, Ca and Fe were more complex.

  3. Effect of ultrasound energy on the zeolitization of chemical extracts from fused coal fly ash.

    Science.gov (United States)

    Bukhari, Syed Salman; Rohani, Sohrab; Kazemian, Hossein

    2016-01-01

    This paper investigates the effects of ultrasound (UTS) energy at different temperatures on the zeolitization of aluminosilicate constituents of coal fly ash. UTS energy irradiated directly into the reaction mixture utilizing a probe immersed into the reaction mixture, unlike previously reported works that have used UTS baths. Controlled synthesis was also conducted at constant stirring and at the same temperatures using conventional heating. The precursor reaction solution was obtained by first fusing the coal fly ash with sodium hydroxide at 550°C followed by dissolution in water and filtration. The synthesized samples were characterized by XRF, XRD, SEM and TGA. The crystallinity of crystals produced with UTS assisted conversion compared to conventional conversion at 85°C was twice as high. UTS energy also reduced the induction time from 60 min to 40 min and from 80 min to 60 min for reaction temperatures of 95°C and 85°C, respectively. Prolonging the UTS irradiation at 95°C resulted in the conversion of zeolite-A crystals to hydroxysodalite, which is a more stable zeolitic phase. It was found that at 85°C coupled with ultrasound energy produced the best crystalline structure with a pure single phase of zeolite-A. It has been shown that crystallization using UTS energy can produce zeolitic crystals at lower temperatures and within 1h, dramatically cutting the synthesis time of zeolite. PMID:26384882

  4. Biosynthesis of titanium dioxide nanoparticles using a probiotic from coal fly ash effluent

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Metal resistant probiotic species was isolated from coal fly ash effluent site. • Uniform sized anatase form of TiO2 nanoparticles were synthesized using Propionibacterium jensenii. • Diffraction patterns confirmed the anatase – TiO2 NPs with average size 2 nanoparticle incorporated wound dressing exhibits better wound healing. - Abstract: The synthesis of titanium dioxide nanoparticle (TiO2 NP) has gained importance in the recent years owing to its wide range of potential biological applications. The present study demonstrates the synthesis of TiO2 NPs by a metal resistant bacterium isolated from the coal fly ash effluent. This bacterial strain was identified on the basis of morphology and 16s rDNA gene sequence [KC545833]. The physico-chemical characterization of the synthesized nanoparticles is completely elucidated by energy dispersive X-ray analysis (EDAX), Fourier transform infrared spectroscopy (FTIR) and transmission and scanning electron microscopy (TEM, SEM). The crystalline nature of the nanoparticles was confirmed by X-RD pattern. Further, cell viability and haemolytic assays confirmed the biocompatible and non toxic nature of the NPs. The TiO2 NPs was found to enhance the collagen stabilization and thereby enabling the preparation of collagen based biological wound dressing. The paper essentially provides scope for an easy bioprocess for the synthesis of TiO2 NPs from the metal oxide enriched effluent sample for future biological applications

  5. Elaboration of new ceramic microfiltration membranes from mineral coal fly ash applied to waste water treatment.

    Science.gov (United States)

    Jedidi, Ilyes; Saïdi, Sami; Khemakhem, Sabeur; Larbot, André; Elloumi-Ammar, Najwa; Fourati, Amine; Charfi, Aboulhassan; Salah, Abdelhamid Ben; Amar, Raja Ben

    2009-12-15

    This work aims to develop a new mineral porous tubular membrane based on mineral coal fly ash. Finely ground mineral coal powder was calcinated at 700 degrees C for about 3 h. The elaboration of the mesoporous layer was performed by the slip-casting method using a suspension made of the mixture of fly-ash powder, water and polyvinyl alcohol (PVA). The obtained membrane was submitted to a thermal treatment which consists in drying at room temperature for 24 h then a sintering at 800 degrees C. SEM photographs indicated that the membrane surface was homogeneous and did not present any macrodefects (cracks, etc...). The average pore diameter of the active layer was 0.25 microm and the thickness was around 20 microm. The membrane permeability was 475 l/h m(2) bar. This membrane was applied to the treatment of the dying effluents generated by the washing baths in the textile industry. The performances in term of permeate flux and efficiency were determined and compared to those obtained using a commercial alumina microfiltration membrane. Almost the same stabilised permeate flux was obtained (about 100 l h(-1)m(-2)). The quality of permeate was almost the same with the two membranes: the COD and color removal was 75% and 90% respectively. PMID:19699033

  6. Biosynthesis of titanium dioxide nanoparticles using a probiotic from coal fly ash effluent

    Energy Technology Data Exchange (ETDEWEB)

    Babitha, S; Korrapati, Purna Sai, E-mail: purnasaik.clri@gmail.com

    2013-11-15

    Graphical abstract: - Highlights: • Metal resistant probiotic species was isolated from coal fly ash effluent site. • Uniform sized anatase form of TiO{sub 2} nanoparticles were synthesized using Propionibacterium jensenii. • Diffraction patterns confirmed the anatase – TiO{sub 2} NPs with average size <80 nm. • TiO{sub 2} nanoparticle incorporated wound dressing exhibits better wound healing. - Abstract: The synthesis of titanium dioxide nanoparticle (TiO{sub 2} NP) has gained importance in the recent years owing to its wide range of potential biological applications. The present study demonstrates the synthesis of TiO{sub 2} NPs by a metal resistant bacterium isolated from the coal fly ash effluent. This bacterial strain was identified on the basis of morphology and 16s rDNA gene sequence [KC545833]. The physico-chemical characterization of the synthesized nanoparticles is completely elucidated by energy dispersive X-ray analysis (EDAX), Fourier transform infrared spectroscopy (FTIR) and transmission and scanning electron microscopy (TEM, SEM). The crystalline nature of the nanoparticles was confirmed by X-RD pattern. Further, cell viability and haemolytic assays confirmed the biocompatible and non toxic nature of the NPs. The TiO{sub 2} NPs was found to enhance the collagen stabilization and thereby enabling the preparation of collagen based biological wound dressing. The paper essentially provides scope for an easy bioprocess for the synthesis of TiO{sub 2} NPs from the metal oxide enriched effluent sample for future biological applications.

  7. An environmentally-friendly vacuum reduction metallurgical process to recover germanium from coal fly ash.

    Science.gov (United States)

    Zhang, Lingen; Xu, Zhenming

    2016-07-15

    The demand for germanium in the field of semiconductor, electronics, and optical devices is growing rapidly; however, the resources of germanium are scarce worldwide. As a secondary material, coal fly ash could be further recycled to retrieve germanium. Up to now, the conventional processes to recover germanium have two problems as follows: on the one hand, it is difficult to be satisfactory for its economic and environmental effect; on the other hand, the recovery ratio of germanium is not all that could be desired. In this paper, an environmentally-friendly vacuum reduction metallurgical process (VRMP) was proposed to recover germanium from coal fly ash. The results of the laboratory scale experiments indicated that the appropriate parameters were 1173K and 10Pa with 10wt% coke addition for 40min, and recovery ratio germanium was 93.96%. On the basis of above condition, the pilot scale experiments were utilized to assess the actual effect of VRMP for recovery of germanium with parameter of 1473K, 1-10Pa and heating time 40min, the recovery ratio of germanium reached 94.64%. This process considerably enhances germanium recovery, meanwhile, eliminates much of the water usage and residue secondary pollution compared with other conventional processes. PMID:27015376

  8. Recycling of Coal Fly Ash for the Fabrication of Porous Mullite/Alumina Composites

    Directory of Open Access Journals (Sweden)

    Kyu H. Kim

    2014-08-01

    Full Text Available Coal fly ash with the addition of Al2O3 was recycled to produce mullite/alumina composites and the camphene-based freeze casting technique was processed to develop a controlled porous structure with improved mechanical strength. Many rod-shaped mullite crystals, formed by the mullitization of coal fly ash in the presence of enough silicate, melt. After sintering at 1300–1500 °C with the initial solid loadings of 30–50 wt.%, interconnected macro-sized pore channels with nearly circular-shaped cross-sections developed along the macroscopic solidification direction of camphene solvent used in freeze casting and a few micron-sized pores formed in the walls of the pore channels. The macro-pore size of the mullite/alumina composites was in the range 20–25 μm, 18–20 μm and 15–17 μm with reverse dependence on the sintering temperature at 30, 40 and 50 wt.% solid loading, respectively. By increasing initial solid loading and the sintering temperature, the sintered porosity was reduced from 79.8% to 31.2%, resulting in an increase in the compressive strength from 8.2 to 80.4 MPa.

  9. Elaboration of new ceramic microfiltration membranes from mineral coal fly ash applied to waste water treatment

    Energy Technology Data Exchange (ETDEWEB)

    Jedidi, I.; Saidi, S.; Khemakhem, S.; Larbot, A.; Elloumi-Ammar, N.; Fourati, A.; Charfi, A.; Salah, A.B.; Amar, R.B. [Science Faculty of Sfax, Sfax (Tunisia)

    2009-12-15

    This work aims to develop a new mineral porous tubular membrane based on mineral coal fly ash. Finely ground mineral coal powder was calcinated at 700{sup o}C for about 3 h. The elaboration of the mesoporous layer was performed by the slip-casting method using a suspension made of the mixture of fly-ash powder, water and polyvinyl alcohol (PVA). The obtained membrane was submitted to a thermal treatment which consists in drying at room temperature for 24h then a sintering at 800{sup o}C. SEM photographs indicated that the membrane surface was homogeneous and did not present any macrodefects (cracks, etc...). The average pore diameter of the active layer was 0.25 {mu} m and the thickness was around 20 {mu} m. The membrane permeability was 475 l/h m{sup 2} bar. This membrane was applied to the treatment of the dying effluents generated by the washing baths in the textile industry. The performances in term of permeate flux and efficiency were determined and compared to those obtained using a commercial alumina microfiltration membrane. Almost the same stabilised permeate flux was obtained (about 1001 h{sup -1} m{sup -2}). The quality of permeate was almost the same with the two membranes: the COD and color removal was 75% and 90% respectively.

  10. Responses of heterotrophic bacterial populations to pH changes in coal ash effluent

    Energy Technology Data Exchange (ETDEWEB)

    Guthrie, R.K. (Univ. of Texas, Houston); Cherry, D.S.; Singleton, F.L.

    1978-08-01

    Total culturable heterotrophic bacteria in a coal ash basin and drainage system were monitored over a period of two years. In the first year heavy (bottom) ash was sluiced to the basin resulting in a pH of 6.5. During the second year fly ash was precipitated and added to the sluice lowering the basin pH to 4.6. Sulfate concentrations during 1975 ranged from 16 to 73 ppM (mean 33) and in 1976 from 44 to 88 ppM (mean 72). Mean annual basin temperatures were 28.8 and 26.0/sup 0/C, respectively. Approximately 1500 m in the receiving swamp below the basin, mean pH and temperature were 6.8 and 22.2/sup 0/C for the first year, and 5.4 and 22.1/sup 0/C for the second. Total culturable bacteria and diversity (colony types) were reduced at all sampling stations by 44 and 30%, respectively, whereas the percentage of the population comprised of chromagenic bacteria increased by 51% at the lower pH. Data indicated the pH had a greater effect than did water temperature when temperature was within the range of 15 to 25/sup 0/C. The predominant genera within the system in the first year were Bacillus, Sarcina, Achromobacter, Flavobacterium, and Pseudomonas. In the second year, at the lower pH, predominant genera were Pseudomonas, Flavobacterium, Chromobacterium, Bacillus, and Brevibacterium.

  11. Mineralogy and heavy metal leachability of magnetic fractions separated from some Chinese coal fly ashes

    International Nuclear Information System (INIS)

    Magnetic fractions (MFs) in fly ashes from eight coal-burning power plants were extracted by magnetic separation procedure. Their mineralogy and potential leachability of heavy metals were analyzed using rock magnetism, X-ray diffraction (XRD), scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (SEM/EDX) and leaching procedures (toxicity characteristics leaching procedure by the United States Environmental Protection Agency, TCLP, and gastric juice simulation test, GJST). Results show that the MFs in the fly ashes range between 2.2 and 16.3 wt%, and are generally composed of magnetite, hematite, quartz and mullite. Thermomagnetic analysis and SEM/EDX indicate that the main magnetic carrier magnetite is substituted with small amounts of impure ions, and its structures are featured by rough, dendritic and granular iron spherules. The MFs are found to be rich in Fe, Mn, Cr, Cu, Cd and Pb. Compared with the non-magnetic fractions (NMFs), the MFs have about 5 times higher iron, and 1.6 times higher Mn, Cr, Cu and Cd concentrations. The TCLP test shows that the TCLP-extractable Cr, Cu, and Pb concentrations in the MFs are higher than those in the NMFs, while the TCLP-extractable Cd concentration in the MFs and NMFs is below the detection limit ( Cr > Pb > Cd. The heavy metals of fly ashes have a great potential to be released into the environment under acid environment.

  12. Fly ashes from coal and petroleum coke combustion: current and innovative potential applications.

    Science.gov (United States)

    González, Aixa; Navia, Rodrigo; Moreno, Natalia

    2009-12-01

    Coal fly ashes (CFA) are generated in large amounts worldwide. Current combustion technologies allow the burning of fuels with high sulfur content such as petroleum coke, generating non-CFA, such as petroleum coke fly ash (PCFA), mainly from fluidized bed combustion processes. The disposal of CFA and PCFA fly ashes can have severe impacts in the environment such as a potential groundwater contamination by the leaching of heavy metals and/or particulate matter emissions; making it necessary to treat or reuse them. At present CFA are utilized in several applications fields such as cement and concrete production, agriculture and soil stabilization. However, their reuse is restricted by the quality parameters of the end-product or requirements defined by the production process. Therefore, secondary material markets can use a limited amount of CFA, which implies the necessity of new markets for the unused CFA. Some potential future utilization options reviewed herein are zeolite synthesis and valuable metals extraction. In comparison to CFA, PCFA are characterized by a high Ca content, suggesting a possible use as neutralizers of acid wastewaters from mining operations, opening a new potential application area for PCFA that could solve contamination problems in emergent and mining countries such as Chile. However, this potential application may be limited by PCFA heavy metals leaching, mainly V and Ni, which are present in PCFA in high concentrations.

  13. Fly ashes from coal and petroleum coke combustion: current and innovative potential applications

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, A.; Navia, R.; Moreno, N. [University La Frontera, Temuco (Chile). Dept. of Chemical Engineering

    2009-12-15

    Coal fly ashes (CFA) are generated in large amounts worldwide. Current combustion technologies allow the burning of fuels with high sulfur content such as petroleum coke, generating non-CFA, such as petroleum coke fly ash (PCFA), mainly from fluidized bed combustion processes. The disposal of CFA and PCFA fly ashes can have severe impacts in the environment such as a potential groundwater contamination by the leaching of heavy metals and/or particulate matter emissions; making it necessary to treat or reuse them. At present CFA are utilized in several applications fields such as cement and concrete production, agriculture and soil stabilization. However, their reuse is restricted by the quality parameters of the end-product or requirements defined by the production process. Therefore, secondary material markets can use a limited amount of CFA, which implies the necessity of new markets for the unused CFA. Some potential future utilization options reviewed herein are zeolite synthesis and valuable metals extraction. In comparison to CFA, PCFA are characterized by a high Ca content, suggesting a possible use as neutralizers of acid wastewaters from mining operations, opening a new potential application area for PCFA that could solve contamination problems in emergent and mining countries such as Chile. However, this potential application may be limited by PCFA heavy metals leaching, mainly V and Ni, which are present in PCFA in high concentrations.

  14. Direct synthesis of carbon nanofibers from South African coal fly ash

    Science.gov (United States)

    Hintsho, Nomso; Shaikjee, Ahmed; Masenda, Hilary; Naidoo, Deena; Billing, Dave; Franklyn, Paul; Durbach, Shane

    2014-08-01

    Carbon nanofibers (CNFs), cylindrical nanostructures containing graphene, were synthesized directly from South African fly ash (a waste product formed during the combustion of coal). The CNFs (as well as other carbonaceous materials like carbon nanotubes (CNTs)) were produced by the catalytic chemical vapour deposition method (CCVD) in the presence of acetylene gas at temperatures ranging from 400°C to 700°C. The fly ash and its carbonaceous products were characterized by transmission electron microscopy (TEM), thermogravimetric analysis (TGA), laser Raman spectroscopy and Brunauer-Emmett-Teller (BET) surface area measurements. It was observed that as-received fly ash was capable of producing CNFs in high yield by CCVD, starting at a relatively low temperature of 400°C. Laser Raman spectra and TGA thermograms showed that the carbonaceous products which formed were mostly disordered. Small bundles of CNTs and CNFs observed by TEM and energy-dispersive spectroscopy (EDS) showed that the catalyst most likely responsible for CNF formation was iron in the form of cementite; X-ray diffraction (XRD) and Mössbauer spectroscopy confirmed these findings.

  15. Magnetic tracing of coal slag and ash in a river basin

    Science.gov (United States)

    Appel, Erwin; Frančišković-Bilinski, Stanislav; Zhang, Qi; Rösler, Wolfgang; Zhang, Qian

    2016-04-01

    Atmospheric distribution of pollutants by magnetic means has been extensively studied, but only little is known about pollution-related magnetic signatures for aquatic transport. The case of a textile factory in Croatia that released heavy-metal polluted and highly magnetic ash and slag material from coal burning into Mrežnica River for 110 years (1884-1994) represents an ideal target for studying principles of magnetic tracing through a river system. Samples from the riverside close to the factory show high concentrations of magnetite (mass-specific susceptibility χ ˜1-4 x10‑5 m3kg‑1) with low frequency dependence (χfd% 100 m from the riverside. The spatial pattern of shallow vertical sections of χ (surface to ˜0.5 m depth) shows different layers of coal burning residues which may even allow discriminating different flooding events (historical flooding). In order to assess the possible influence of fly ash from the factory, we studied vertical soil profiles at locations which cannot be reached by floods. These (red) soils, formed on limestones, are strongly magnetic (χ >10‑6 m3kg‑1). Despite this strong natural magnetic signals, the depth dependence of χfd% and characteristic chemical properties (sulfur content, Ni/Cu ratio) as well as the dependence of the vertical χ distribution with distance to the point source indicate a contribution of fly ash to soil contamination near the factory (within about one kilometer). The presently available results indicate that with a strong magnetic point source as in the case of the studied textile factory, magnetic tracing can contribute important information on the transport and mass balance of sediments in a river basin.

  16. Characterisation and reaction kinetics of high ash chars derived from inertinite-rich coal discards / Rufaro Kaitano

    OpenAIRE

    Kaitano, Rufaro

    2007-01-01

    An investigation was undertaken to determine the gasification and combustion characteristics of chars derived from an inertinite-rich coal discard sample with a high ash content. Fundamental knowledge of the reaction rate kinetics for char conversion at reactions conditions used in fluidised bed gasification and combustion was obtained. For this purpose, characterisation of the parent coal and derived chars, reactivity determinations of the chars and detailed reaction rate mode...

  17. Coal fly ash interaction with environmental fluids: Geochemical and strontium isotope results from combined column and batch leaching experiments

    International Nuclear Information System (INIS)

    Highlights: ► Element release during fly ash extraction experiments controlled by mineralogy. ► Strontium isotopes in fly ash are not homogenized during coal combustion. ► Element correlations with 87Sr/86Sr indicate chemically resistant silicate phase. ► Sr isotopes can uniquely identify fly ash fluids leaking into the environment. - Abstract: The major element and Sr isotope systematics and geochemistry of coal fly ash and its interactions with environmental waters were investigated using laboratory flow-through column leaching experiments (sodium carbonate, acetic acid, nitric acid) and sequential batch leaching experiments (water, acetic acid, hydrochloric acid). Column leaching of Class F fly ash samples shows rapid release of most major elements early in the leaching procedure, suggesting an association of these elements with soluble and surface bound phases. Delayed release of certain elements (e.g., Al, Fe, Si) signals gradual dissolution of more resistant silicate or glass phases as leaching continues. Strontium isotope results from both column and batch leaching experiments show a marked increase in 87Sr/86Sr ratio with continued leaching, yielding a total range of values from 0.7107 to 0.7138. For comparison, the isotopic composition of fluid output from a fly ash impoundment in West Virginia falls in a narrow range around 0.7124. The experimental data suggest the presence of a more resistant, highly radiogenic silicate phase that survives the combustion process and is leached after the more soluble minerals are removed. Strontium isotopic homogenization of minerals in coal does not always occur during the combustion process, despite the high temperatures encountered in the boiler. Early-released Sr tends to be isotopically uniform; thus the Sr isotopic composition of fly ash could be distinguishable from other sources and is a useful tool for quantifying the possible contribution of fly ash leaching to the total dissolved load in natural surface

  18. The Influence Of Calcite On The Ash Flow Temperature For Semi-Anthracite Coal From Donbas District

    Directory of Open Access Journals (Sweden)

    Čarnogurská Mária

    2014-12-01

    Full Text Available This paper presents the results of research focused on the lowering of ash flow temperature at semianthracite coal from Donbas district by means of additive (calcite dosing. Ash fusion temperatures were set for two coal samples (A, B and for five various states (samples of ash without any additives, with 1%, with 3%, with 5% and with 7% of the additive in total. The macroscopicphotographic method was used for identifying all specific temperatures. Obtained outputs prove that A type coal has a lower value of sphere temperature than B type coal in the whole scope of percentage representation of the additive. The flow temperature dropped in total from 1489 °C to 1280 °C, i.e. by 14% during the test of coal of type A with 7% of the additive; while it was near 10% for coal of type B (from 1450 °C to 1308 °C. Numerical simulations of the process showed that it is not effective to add an additive with a grain size lower than 280 μm by means of wastevapour burners.

  19. Determination of benzo[a]pyrene and dibenzopyrenes in a Chinese coal fly ash certified reference material.

    Science.gov (United States)

    Masala, Silvia; Bergvall, Christoffer; Westerholm, Roger

    2012-08-15

    Air pollution from coal combustion is of great concern in China because coal is the country's principal source of energy and it has been estimated that coal combustion is one of the main sources of polycyclic aromatic hydrocarbon (PAH) emissions in the nation. This study reports the concentrations of 15 PAHs including benzo[a]pyrene, dibenzo[a,l]pyrene, dibenzo[a,e]pyrene, dibenzo[a,i]pyrene and dibenzo[a,h]pyrene in a coal fly ash certified reference material (CRM) from China. To the best of our knowledge, dibenzo[a,l]pyrene, dibenzo[a,i]pyrene and dibenzo[a,h]pyrene concentrations in coal fly ash particles have not previously been reported. Benzo[a]pyrene is the only one of the studied hydrocarbons whose concentration in the coal fly ash CRM had previously been certified. The concentration of this species measured in this present work was twice the certified value. This is probably because of the exhaustive accelerated solvent extraction method employed. Consecutive extractions indicated an extraction recovery in excess of 95% for benzo[a]pyrene. For the other determined PAHs, repeat extractions indicated recoveries above 90%. PMID:22728296

  20. Waste Minimization Protocols for the Process of Synthesizing Zeolites from South African Coal Fly Ash

    Directory of Open Access Journals (Sweden)

    Leslie F. Petrik

    2013-04-01

    Full Text Available Production of a high value zeolite from fly ash has been shown to be an avenue for the utilization of South African fly ash which presently constitutes a huge disposal problem. The synthesis of zeolites Na-P1 and analcime on a micro-scale has been successful and preliminary investigation shows that scale-up synthesis is promising. However, the post-synthesis supernatant waste generated contains high levels of NaOH that may constitute a secondary disposal problem. A waste minimization protocol was developed to reduce the volume of waste generated with a view to enhancing the feasibility of the scale synthesis. Series of experiments were conducted in 100 mL jacketed batch reactors. Fly ash was reacted with 5 Mol NaOH on a 1:1 mass basis during the aging step, followed by hydrothermal treatment in which ultrapure water was added to the slurry. This study shows that by re-introducing the supernatant waste into the experiments in such a way that it supplies the required reagent (NaOH for the zeolite synthesis, zeolite Na-P1 and analcime can be synthesized. It also shows that the synthesis process can be altered to allow up to 100% re-use of the supernatant waste to yield high value zeolitic products. This study effectively constructed two protocols for the minimization of waste generated during the synthesis of zeolites from South African coal fly ash. This result could be used to establish a basis for legal and environmental aspects involved in the commission of a full-scale plant synthesizing zeolites NaP1 and analcime.

  1. The bonding of heavy metals on nitric acid-etched coal fly ashes functionalized with 2-mercaptoethanol or thioglycolic acid

    International Nuclear Information System (INIS)

    Coal fly ash is a waste by-product of the coal fire industry, which generates many environmental problems. Alternative uses of this material would provide efficient solutions for this by-product. In this work, nitric acid-etched coal fly ash labelled with 2-mercaptoethanol or thioglycolic acid was assessed for retention of Al(III), As(III), Cu(II), Cd(II), Fe(III), Mn(II), Hg(II), Ni(II), Pb(II) and Zn(II) ions. The bonding characteristics between the organic compounds with the solid support, as well as with the metal ions, were evaluated using various surface analytical techniques. Visualization of the organically-functionalized coal fly ash particle was possible using scanning electron microscopy (SEM), while the elemental composition of the functionalized material, before and after retention of the metal ions, was obtained by energy dispersive (ED)-X ray spectrometry (XRS) and electrothermal atomic absorption spectrometry (ETAAS). Fourier transform infrared (FT-IR) spectrometry and Raman spectrometry were used to obtain information about the functional groups. It was found that some metal(oid) ions (As, Ni, Pb, Zn) were coordinated through the mercaptan group, while other metal(oid)s (Al, Cd, Cu, Fe, Hg, Mn) were apparently bonded to oxygen atoms. A low-cost and effective solid phase retention system for extraction of heavy metals from aqueous solutions was thus developed. - Graphical abstract: Nitric acid-etched coal fly ash labelled with 2-mercaptoethanol or thioglycolic acid was intended for the retention of heavy metals. The bonding characteristics between the organic compounds with the solid support, as well as with the metal ions, were evaluated using surface analytical techniques. - Highlights: • Coal fly ashes were organically-functionalized. • Organically-functionalized coal fly ashes were spectrometrically characterized. • Organically-functionalized coal fly ashes can be used as an effective solid sorbent for metal(oid)s. • This retention

  2. Rare earth elements in fly ashes created during the coal burning process in certain coal-fired power plants operating in Poland - Upper Silesian Industrial Region

    Energy Technology Data Exchange (ETDEWEB)

    Smolka-Danielowska, D. [University of Silesia, Sosnowiec (Poland). Faculty of Earth Science

    2010-11-15

    The subject of the study covered volatile ashes created during hard coal burning process in ash furnaces, in power plants operating in the Upper Silesian Industrial Region, Southern Poland. Coal-fired power plants are furnished with dust extracting devices, electro precipitators, with 99-99.6% combustion gas extracting efficiency. Activity concentrations of Th-232, Ra-226, K-40, Ac-228, U-235 and U-238 were measured with gamma-ray spectrometer. Concentrations of selected rare soil elements (La, Ce, Nd, Sm, Y, Gd, Th, U) were analysed by means of instrumental neutron activation analysis (INAA). Mineral phases of individual ash particles were identified with the use of scanning electron microscope equipped with EDS attachment. Laser granulometric analyses were executed with the use of Analyssette analyser. The activity of the investigated fly-ash samples is several times higher than that of the bituminous coal samples; in the coal, the activities are: {sup 226}Ra - 85.4 Bq kg{sup -1}, {sup 40}K-689 Bq kg{sup -1}, {sup 232}Th - 100.8 Bq kg{sup -1}, {sup 235}U - 13.5 Bq kg{sup -1}, {sup 238}U - 50 Bq kg{sup -1} and {sup 228}Ac - 82.4 Bq kg{sup -1}.

  3. Rare earth elements in fly ashes created during the coal burning process in certain coal-fired power plants operating in Poland - Upper Silesian Industrial Region.

    Science.gov (United States)

    Smolka-Danielowska, Danuta

    2010-11-01

    The subject of the study covered volatile ashes created during hard coal burning process in ash furnaces, in power plants operating in the Upper Silesian Industrial Region, Southern Poland. Coal-fired power plants are furnished with dust extracting devices, electro precipitators, with 99-99.6% combustion gas extracting efficiency. Activity concentrations ofTh-232, Ra-226, K-40, Ac-228, U-235 and U-238 were measured with gamma-ray spectrometer. Concentrations of selected rare soil elements (La, Ce, Nd, Sm, Y, Gd, Th, U) were analysed by means of instrumental neutron activation analysis (INAA). Mineral phases of individual ash particles were identified with the use of scanning electron microscope equipped with EDS attachment. Laser granulometric analyses were executed with the use of Analyssette analyser. The activity of the investigated fly-ash samples is several times higher than that of the bituminous coal samples; in the coal, the activities are: 226Ra - 85.4 Bq kg(-1), 40 K-689 Bq kg(-1), 232Th - 100.8 Bq kg(-1), 235U-13.5 Bq kg(-1), 238U-50 Bq kg(-1) and 228Ac - 82.4 Bq kg(-1).

  4. Beneficiation of pulverized coal combustion fly ash in fluidised bed reactors

    Energy Technology Data Exchange (ETDEWEB)

    Cammarota, A.; Chirone, R.; Solimene, R.; Urciuolo, M. [Istituto di Ricerche sulla Combustione - C.N.R., P.le V. Tecchio 80, 80125 Napoli (Italy)

    2008-07-15

    The paper addresses the thermal treatment of pulverized coal combustion fly ash belonging to the group C of Geldart powder classification in unconventional configurations of fluidised bed reactors. A sound-assisted fluidised bed combustor operated at 850 and 750 C, and a fluidised bed combustor characterized by a conical geometry, operated at 850 C, are the two lab-scale reactors tested. Combustion experiments have been carried out at different air excesses, ranging between 10% and 170%, and in the case of the conical fluidization column with different bed inventory. Both tested configurations have been proved to be efficient to reduce the carbon content initially present in the fly ash of 11%{sub w}, to a very low level, generally smaller than 1%{sub w}. Both the fly ash residence time in the reactor and the air excess strongly influenced the reactor performance. Residence times of 3-4 min and 10-60 min have been estimated for experiments carried out with the sound-assisted fluidised bed combustor and with the conical fluidised bed combustor, respectively. Regarding the possibility of a concurrent reduction of unburned carbon in the ash and of a particle size separation of the beneficiated material, on the basis of the obtained experimental data, the sound-assisted fluidised bed combustor is not able to separate the broad particle size distribution of the fly ash in different outlet solid streams. The use of a conical fluidised bed combustor is promising to realize an efficient separation of the inlet broad particle size distribution of the fly ash fed to the reactor into narrower outlet solid streams extracted from different locations: combustor exit, top and bottom of the bed. In this framework a hydrodynamic characterization of binary mixtures in a conical fluidised bed column carried out at ambient and high temperature (850 C) has demonstrated that the operating conditions of the conical fluidised bed combustor can be chosen on the basis of a compromise

  5. Rapid laser fluorometric method for the determination of uranium in soil, ultrabasic rock, plant ash, coal fly ash and red mud samples

    International Nuclear Information System (INIS)

    A simple and rapid laser fluorometric determination of trace and ultra trace level of uranium in a wide variety of low uranium content materials like soil, basic and ultra basic rocks, plant ash, coal fly ash and red mud samples is described. Interference studies of some common major, minor and trace elements likely to be present in different geological materials on uranium fluorescence are studied using different fluorescence enhancing reagents like sodium pyrophosphate, orthophosphoric acid, penta sodium tri-polyphosphate and sodium hexametaphosphate. The accurate determination of very low uranium content samples which are rich in iron, manganese and calcium, is possible only after the selective separation of uranium. Conditions suitable for the quantitative single step extraction of 25 ng to 20 μg uranium with tri-n-octylphosphine oxide and single step quantitative stripping with dilute neutral sodium pyrophosphate, which also acts as fluorescence enhancing reagent is studied. The aqueous strip is used for the direct laser fluorometric measurement without any further pretreatment. The procedure is applied for the determination of uranium in soil, basalt, plant ash, coal fly ash and red mud samples. The accuracy of the proposed method is checked by analyzing certain standard reference materials as well as synthetic sample with known quantity of uranium. The accuracy and reproducibility of the method are fairly good with RSD ranging from 3 to 5% depend upon the concentration of uranium. (author)

  6. Estabilização de solo contaminado com zinco usando zeólitas sintetizadas a partir de cinzas de carvão Stabilization of zinc-contamined soil using zeolites synthesized from coal ashes

    Directory of Open Access Journals (Sweden)

    Denise Alves Fungaro

    2004-08-01

    Full Text Available The effect of synthetic zeolites on stabilizing Zn-contaminated soil using 0.01 mol L-1 CaCl2 leaching solution in batch experiments was investigated. The zeolites were synthesized from coal ash by hydrothermal treatment with alkaline solution. The additive enhanced the sorption capacity of the soil and reduced leaching. Zinc leaching was reduced by more than 80% using a minimum of 10% additive. The higher cation exchange capacity of the zeolite/soil mixtures and higher pH were responsible for stabilizing Zn in soil. The poly(2-aminobenzenesulfonic acid-coated mercury thin-film electrode was used for the determination of zinc.

  7. Estabilização de solo contaminado com zinco usando zeólitas sintetizadas a partir de cinzas de carvão Stabilization of zinc-contamined soil using zeolites synthesized from coal ashes

    OpenAIRE

    Denise Alves Fungaro; Marlene Sotto-Mayor Flues; Amanda Paccini Celebroni

    2004-01-01

    The effect of synthetic zeolites on stabilizing Zn-contaminated soil using 0.01 mol L-1 CaCl2 leaching solution in batch experiments was investigated. The zeolites were synthesized from coal ash by hydrothermal treatment with alkaline solution. The additive enhanced the sorption capacity of the soil and reduced leaching. Zinc leaching was reduced by more than 80% using a minimum of 10% additive. The higher cation exchange capacity of the zeolite/soil mixtures and higher pH were responsible fo...

  8. Coal-ash as a surfacing material for feedlots to improve energy and nutrient value of manure

    Science.gov (United States)

    Hauling soil/manure out and fill-soil in to maintain adequate feedlot pen surfaces is time consuming and expensive. Pond ash (PA), a by-product from coal-fired electrical generation, has very good support qualities even when wet. Four pens were excavated to a depth of 0.5 m and returned to grade wit...

  9. Study on the structural change and heat transfer characteristics of ash deposit layers in the coal gasifier

    Energy Technology Data Exchange (ETDEWEB)

    Kazuyoshi Ichikawa; Yuso Oki; Jun Inumaru [Central Research Institute of Electric Power Industry (CREIPI) (Japan)

    2005-07-01

    Ash deposition is often observed in the coal gasifier. As it may interfere the operation of gasifier, in case of excessive deposition, a study is needed to evaluate the ash deposition characteristics on the gasifier wall, its ability to grow after deposition, and influence of the formation of deposition layers on the heat transfer capability in advance. CRIEPI has conducted a study of the basic gasification process and operational technology using a 2T/D air-blown pressurized entrained-flow coal gasifier (2 T/D gasifier) since 1983. In a previous work, the authors calculated the ash liquid phase ratio as an index of the ash melting characteristics in correspondence to continuous temperature change, and established the relationship with the ash deposition characteristics. We also proposed as the technique to predict ash deposition characteristics in the gasifier by construction of a model based upon the correlation and introduction into the numerical analysis code. In this report, the relationship between the sintering structure and the heat transfer characteristics of deposition layer is studied. The heat transfer mechanism in the layer was also pursued. 7 refs., 6 figs., 1 tab.

  10. Direct determination of Ge in hot spring waters and coal fly ash samples by hydride generation-ETAAS

    Energy Technology Data Exchange (ETDEWEB)

    Moscoso-Perez, Carmen; Moreda-Pineiro, Jorge; Lopez-Mahia, Purificacion; Muniategui-Lorenzo, Soledad; Fernandez-Fernandez, Esther; Prada-Rodriguez, Dario [Department of Analytical Chemistry, Faculty of Sciences, University of A Coruna, Campus da Zapateira, s/n. E-15071, A Coruna (Spain)

    2004-10-08

    A method for Ge determination in hot spring water and acid extracts from coal fly ash samples involving hydride generation, trapping and atomisation of the hydride generated from Ir-treated graphite tubes (GTs) has been developed. Hydride was generated from hydrochloric acid medium using sodium tetrahydroborate. Several factors affecting the hydride generation, transport, trapping and atomisation efficiency were studied by using a Plackett-Burman design. Results obtained from Plackett-Burman designs suggest that trapping and atomisation temperatures are the significant factors involved on the procedure. The accuracy was studied using NIST-1633a (coal fly ash) reference material. The detection limit of the proposed method was 2.4{mu}gl{sup -1} and the characteristic mass of 233pg was achieved. The Ge concentrations in fly ash and hot spring samples were between 6.25-132{mu}gg{sup -1} and 12.84-36.2{mu}gl{sup -1}.

  11. Research and development of coal ash off-belt bulk analyzer based on PGNAA technique using neutron source

    International Nuclear Information System (INIS)

    IAEA-RCA/RAS on NCS project have been operating from 2001 brought a new conception and approach about application of nuclear and nucleonic techniques in member states. Through 4 cycle of projects (RAS/8/089, RAS/8/094, RAS/8/099 and RAS/8/107), by a step-by-sep technical transfer, higher level on later phase, this technical transfer way has corrected disadvantages and opened new applications, helps the member states from passive receiving to active joining into higher level of technical development for particular application, in each member state. A regional demonstration centre has been set up in Hanoi - Vietnam, to train personnel from around the RCA region in the use of this instrumentation. The centre in Hanoi has been set a coal ash determination instruments using back-scattered gamma and coal ash logging instrument using PGNAA methods. In 2008, through project RAS/8/107, IAEA has aided a neutron generator and Vietnam had a responsibility to develop Ash content Bulk Analysis by PGNAA. Prompt gamma neutron activation analysis technique (PGNAA) is one among advanced techniques over the world. Advantages of this technique are fast analysis, good accuracy, sample process is not required, no influences of measurement environment and analysis of almost elements in the periodic table. Based on this issue, project Research and development of PGNAA coal ash analyser using neutron generator, carried out since 9/2009, finished in 9/2011 have achieved the first achievements in fast coal ash determination. Developed Ash content Bulk Analysis by PGNAA has following technical parameters: result of coal ash determined has absolute error less than 1%; uses Cf-252 neutron source with neutron flux of 0.85 x 106 n/s; uses BGO detector with size of 51 x 51mm, 2000 channels of ADC; analysis time is 600 s; mass of analysed coal sample is 700 kg; PC connected via USB interface on Window XP; neutron dose and gamma dose around the instruments are less than allowed doses in IAEA safety

  12. Recycling of coal fly ash and paper waste to improve low productive red soil in Okinawa, Japan

    Energy Technology Data Exchange (ETDEWEB)

    Jayasinghe, Guttila Yugantha [United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima (Japan); Tokashiki, Yoshihiro; Kinjo, Kazuthoshi [Department of Environmental Sciences, Faculty of Agriculture, University of the Ryukyus, Okinawa (Japan)

    2009-09-15

    Coal fly ash (CFA) and paper waste (PW) related environmental problems and its recycling techniques have been a major challenge to society. Therefore, it is of crucial importance to develop new recycling methods for CFA and PW. This work proposes a potential new way of developing synthetic aggregates (SA) using CFA, PW, starch waste and ammonium sulfate (AS) as a granular nitrogen fertilizer medium, and their utilization as a soil amendment to improve crop production in the low productive acidic red soil of Okinawa, Japan. Three types of SA with three different nitrogen (N) percentages were produced and used to amend acidic red soil in a pot experiment for the cultivation of Komatsuna, which is also called as Japanese mustard spinach (Brassica rapa var. pervidis). SA had a low bulk density (0.58-0.62 g/cm{sup 3}), high water holding capacity (0.60-0.64 kg/kg), high saturated hydraulic conductivity (2.34.10{sup -2} cm/s), high mean weight diameter (MWD) (4.32-4.48 mm), alkaline pH (8.58-8.61), high electrical conductivity (EC) (82.18-84.35 mS/m) and high carbon (C) content (68.71-70.07 g/kg) in comparison with the acidic red soil. The trace element concentrations of the developed SA were below the maximum pollutant concentration of individual metals for land application of sewage sludge given by the US Environmental Protection Agency. Scanning electron microscopic (SEM) studies showed the higher structural surface area of SA, where round shaped CFA particles were embedded into the fibrous PW matrix. Incorporation of SA into the acidic red soil not only enhanced soil fertility but also improved the physical and chemical properties of the soil compared to soil without SA addition. SA addition to the acidic red soil significantly increased the growth and yield parameters of Komatsuna compared to soil without SA addition. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  13. Investigation of the use of fly-ash based autoclaved cellular concrete blocks in coal mines for air duct work. Final report, January 25, 1993--December 31, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Horvath, M.L. [Ohio Edison Co., Akron, OH (United States)

    1995-06-19

    Coal mines are required to provide ventilation to occupied portions of underground mines. Concrete block is used in this process to construct air duct walls. However, normal concrete block is heavy and not easy to work with and eventually fails dramatically after being loaded due to mine ceiling convergence and/or floor heave. Autoclaved cellular concrete block made from (70{plus_minus}%) coal fly ash is lightweight and less rigid when loaded. It is lighter and easier to use than regular concrete block for underground mine applications. It has also been used in surface construction around the world for over 40 years. Ohio Edison along with eight other electric utility companies, the Electric Power Research Institute (EPRI), and North American Cellular Concrete constructed a mobile demonstration plant to produce autoclaved cellular concrete block from utility fly ash. To apply this research in Ohio, Ohio Edison also worked with the Ohio Coal Development Office and CONSOL Inc. to produce autoclaved cellular concrete block not only from coal ash but also from LIMB ash, SNRB ash, and PFBC ash from various clean coal technology projects sponsored by the Ohio Coal Development Office. The purpose of this project was to demonstrate the potential for beneficial use of fly ash and clean coal technology by-products in the production of lightweight block.

  14. Influence of Coal nature and Structure on Ash Size Formation Characteristic and Related pollutant Emissions During CFB Combustion

    Institute of Scientific and Technical Information of China (English)

    MinQIAN; YongjieNA; 等

    2000-01-01

    The size distribution of coal particles in a Circulating Fluidized Bed(CFB) boiler plays a crucial role in the complicated combustion,heat exchange and pollutant emissions in such a plant.Therefore,it is fundamental to study the different factors having influence on the size distribution of coal particles.Above all,the coal itself and in particular,the coal comminution phenomenon is a very influent factor.In the frame of this work,the coal nature (eleentary compostion) and coal internal structure (mineral componeents) are studied in detail.At this intermediary stage,experients on three typical Chinese coals on a 1.5 MWt CFBC pilot plant have been made.Some primary fragmentation test hae also been made in a small lab scale fluidized bed reactor.The resutls from the hot pilot test show i)the variation of coal ash distributions and other CFB performance data due to the cyclone and the coal characteristics and ii) the variation of desulfurization efficiency with limestone.Whereas the bench scale primary fragmentation test,likely linked to the caking propriety of a coal,does not seem to change considerable the char size distribution.

  15. Development and certification of a coal fly ash certified reference material for selected polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Cao, X; Xu, X; Cui, W; Xi, Z

    2001-08-01

    The development and certification of a coal fly ash certified reference material (CRM) for polycyclic aromatic hydrocarbons (PAH) is described; this is the first natural matrix CRM for organic environmental analysis in China. The homogeneity and stability of this material have been tested by HPLC. The concentrations of several PAH were determined by use of two independent, different methods--solvent extraction-HPLC analysis with UV detection coupled with fluorescence detection (FLD) and solvent extraction, isolation with a silica column, and GC analysis with flame ionization detection (FID). Five certified values were determined: phenanthrene 7.1 +/- 2.6 microg g(-1), anthracene 2.0 +/- 0.8 microg g(-1), fluoranthene 7.4 +/- 1.9 microg g(-1), pyrene 7 +/- 2 microg g(-1), and benzo[a]pyrene 1.3 +/- 0.3 microg g(-1). Reference values for several other PAH are also suggested. PMID:11583083

  16. Characterization of coal fly ash nanoparticles and induced oxidative DNA damage in human peripheral blood mononuclear cells

    Energy Technology Data Exchange (ETDEWEB)

    Dwivedi, Sourabh; Saquib, Quaiser; Al-Khedhairy, Abdulaziz A. [Department of Zoology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia); Ali, Al-Yousef Sulaiman [Department of Medical Laboratory Sciences, College of Applied Medical Science, University of Dammam, P.O. Box 1683, Hafr Al Batin-31991 (Saudi Arabia); Musarrat, Javed, E-mail: musarratj1@yahoo.com [Department of Zoology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia); Department of Agricultural Microbiology, Faculty of Agricultural Sciences, AMU, Aligarh202002 (India)

    2012-10-15

    The nano-sized particles present in coal fly ash (CFA) were characterized through the X-ray diffraction (XRD), transmission and scanning electron microscopy (TEM, SEM), atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR) analyses. The XRD data revealed the average crystallite size of the CFA nanoparticles (CFA-NPs) as 14 nm. TEM and SEM imaging demonstrated predominantly spherical and some polymorphic structures in the size range of 11 to 25 nm. The amount of heavy metal associated with CFA particles ({mu}g/g) were determined as Fe (34160.0 {+-} 1.38), Ni (150.8 {+-} 0.78), Cu (99.3 {+-} 0.56) and Cr (64.0 {+-} 0.86). However, the bioavailability of heavy metals in terms of percent release was in the order as Cr > Ni > Cu > Fe in CFA-dimethyl sulfoxide (DMSO) extract. The comet and cytokinesis blocked micronucleus (CBMN) assays revealed substantial genomic DNA damage in peripheral blood mononuclear (PBMN) cells treated with CFA-NPs in Aq and DMSO extracts. About 1.8 and 3.6 strand breaks per unit of DNA were estimated through alkaline unwinding assay at 1:100 DNA nucleotide/CFA ppm ratios with the Aq and DMSO extracts, respectively. The DNA and mitochondrial damage was invariably greater with CFA-DMSO extract vis-a-vis -Aq extract. Generation of superoxide anions (O{sub 2} Bullet {sup -}) and intracellular reactive oxygen species (ROS) through metal redox-cycling, alteration in mitochondrial potential and 8-oxodG production elucidated CFA-NPs induced oxidative stress as a plausible mechanism for CFA-induced genotoxicity. -- Highlights: Black-Right-Pointing-Pointer CFA consists of spherical crystalline nanoparticles in size range of 11-25 nm. Black-Right-Pointing-Pointer Alkaline unwinding assay revealed single-strandedness in CFA treated ctDNA. Black-Right-Pointing-Pointer CFA nanoparticles exhibited the ability to induce ROS and oxidative DNA damage. Black-Right-Pointing-Pointer Comet and CBMN assays revealed DNA and chromosomal

  17. Study of the adsorption of Cd (II from aqueous solution using zeolite-based geopolymer, synthesized from coal fly ash; kinetic, isotherm and thermodynamic studies

    Directory of Open Access Journals (Sweden)

    Hamedreza Javadian

    2015-11-01

    Full Text Available A specific type of zeolite, synthesized from coal fly ash, was used in our batch adsorption experiments in order to adsorb Cd (II ions from aqueous solution. Solid-state conversion of fly ash to an amorphous aluminosilicate adsorbent (geopolymer was investigated under specific conditions. The adsorbent ZFA was characterized using XRD, XRF, FT-IR, FE-SEM, LPS and BET surface area. The optimum conditions of sorption were found to be: a ZFA dose of 0.08 g in 25 mL of Cd (II with contact time of 7 h and pH 5. Four equations, namely Morris–Weber, Lagergren, Pseudo-second order and Elovich have been used in order to determine the kinetics of removal process. The collected kinetic data showed that pseudo-second order equations controlled the adsorption process. According to adsorption isotherm studies, the Langmuir isotherm was proved to be the best fit for our experimental data, in comparison to Freundlich, D–R and Tempkin models. The thermodynamic parameters ΔH, ΔS and ΔG are evaluated. Thermodynamic parameters showed that the adsorption of Cd (II onto ZFA was feasible, spontaneous and endothermic under studied conditions. To conduct desorption experiments, several solvents (including alkaline, bases and water have been employed. 84% of desorption efficiency was achieved using NaOH.

  18. Removal of heavy metals from wastewater using CFB-coal fly ash zeolitic materials

    International Nuclear Information System (INIS)

    Polish bituminous (PB) and South African (SA) coal fly ash (FA) samples, derived from pilot-scale circulated fluidized bed (CFB) combustion facilities, were utilized as raw materials for the synthesis of zeolitic products. The two FAs underwent a hydrothermal activation with 1 M NaOH solution. Two different FA/NaOH solution/ratios (50, 100 g/L) were applied for each sample and several zeolitic materials were formed. The experimental products were characterized by means of X-ray diffraction (XRD) and energy dispersive X-ray coupled-scanning electron microscope (EDX/SEM), while X-ray fluorescence (XRF) was applied for the determination of their chemical composition. The zeolitic products were also evaluated in terms of their cation exchange capacity (CEC), specific surface area (SSA), specific gravity (SG), particle size distribution (PSD), pH and the range of their micro- and macroporosity. Afterwards the hybrid materials were tested for their ability of adsorbing Cr, Pb, Ni, Cu, Cd and Zn from contaminated liquids. Main parameters for the precipitation of the heavy metals, as it was concluded from the experimental results, are the mineralogical composition of the initial fly ashes, as well as the type and the amount of the produced zeolite and specifically the mechanism by which the metals ions are hold on the substrate.

  19. The Swedish Ash Programme 2002-2008. Biomass, wastes, peat - any solid fuel but coal

    Energy Technology Data Exchange (ETDEWEB)

    Bjurstroem, Henrik; Herbert, Roger

    2009-07-15

    In Sweden, producers of combustion residues have since 2002 implemented a collaborative applied RandD programme aimed at the utilisation of combustion residues (ash). The fuels are biomass, wastes, peat - any solid fuel but coal. In this report, the main lines of the programme are described: Covers for landfills and mine tailings; Civil works, e.g. road-buildings, where both geotechnical and environmental questions have been addressed; Cement and concrete applications; Compensating soils for removing biomass and the mineral nutrients in the biomass. The emphasis of the Programme is on environmental questions, even if technical questions have been treated. The time perspective in this context is much longer than the 3-5 years that are usual in an applied RandD programme, i.e. decades after ash has been placed on a site, e.g. in a road, or spread to forest soil. New test fields have been created in the programme and old test fields have been evaluated in order to gather available information

  20. Bioaccumulation of selenium from coal fly ash and associated environmental hazards in a freshwater fish community

    International Nuclear Information System (INIS)

    Bioaccumulation of Se by fish from Pigeon River and Pigeon Lake, Michigan, which receive inputs of Se from a coal fly-ash disposal facility, was studied to assess potential hazards of Se toxicity to fish and wildlife. Se concentrations in fish from sites receiving Se inputs from fly ash disposal ponds were significantly greater than concentrations in fish from upstream sites, which were near normal background concentrations. Se bioaccumulation differed substantially among fish species, especially in the most contaminated site, where whole-body Se concentrations for the five species analyzed ranged from 1.4 to 3.8 microg/g (wet wt.). The top predator in the community, northern pike (Esox lucius), had Se concentrations less than those in likely prey species. Among lower-order consumers, Se concentrations were greater in limnetic species (spottail shiner, Notropis hudsonius, and yellow perch, Perca flavescens), than in benthic species (white sucker, Catostomus commersoni, and rock bass, Ambloplites rupestris). Se concentrations in tissues of fish from the lower Pigeon River and Pigeon Lake approached, but did not exceed lowest observable effect concentrations (LOAECs) for Se in tissues of sensitive fish species. However, Se concentrations in several fish species exceeded LOAECs for dietary Se exposure of sensitive species of birds and mammals, suggesting that consumption of fish in these areas may pose a hazard to piscivorous wildlife

  1. A Comparative study Of Catalityc Activity Of Heterogeneous Base Of Banana Stem Ash And Fly Ash On Production Of Biodiesel Byultrasonic

    Directory of Open Access Journals (Sweden)

    Marlinda

    2015-08-01

    Full Text Available Abstract The use of heterogeneous catalysts in the production of biodiesel provides many advantages due to heterogeneous catalysts can be easily separated from the product so that it can be reused. This research using heterogeneous catalysts derived from natural materials namely banana stem ash and coal fly ash containing alkali and alkaline earth elements. The preparation of catalyst from banana stem ash and coal fly ash used activator KOH 1.9 N and impregnation with KNO3 15 and then heated to a temperature of 550 0C for 3 hours. Results of preparation banana stem ash contains potassium of 36.52 and surface area of 41.901 m2g. This work presents the effect of ultrasonic assisted of waste cooking oil with methanol as solvent using banana stem ash and coal fly ash as catalyst. The diameter of catalyst particles of banana stem ash and coal fly ash varied at 50 100 150 200 and 250 mesh. The transesterification reaction was performed in the presence of ultrasonic operating frequency constant at 40 kHz methanol molar ratio to oil of 9 1 and reaction time of 30 minutes. The methyl ester biodiesel content of product was 93.26 of banana stems ash and 57 of coal fly ash respectively. The physical property was compared with the National Indonesia Standard SNI 2006 with a density viscosity cloud point flash point and cetane number.

  2. Experimental investigation of ash deposits characteristics of co-combustion of coal and rice hull using a digital image technique

    International Nuclear Information System (INIS)

    This paper investigated the ash deposit characteristics during the co-firing Da Tong (DA) coal with different proportions of rice hull (0%, 5%, 10%, and 20%, based on weight) in a pilot-scale furnace. The growth of ash deposit with a four-stage mode was presented. The stable thickness values of DA coal, 5% rice hull, 10% rice hull, and 20% rice hull were 0.5, 1.4, 2.9, 5.7 cm, with stable heat flux values of 230, 200, 175, and 125 kW/m2, respectively. According to the results of scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDX), the amount of Si in the deposits increased with the increasing proportion of rice hull rich in SiO2. The X-ray diffraction (XRD) analysis results indicated that most elements except Si were in the amorphous state because of the formation of eutectics. The stable thicknesses of deposits increased exponentially with the proportion of rice hull. The deposit was loose, easy removable but it reduced the heat transfer significantly. Consequently, sootblowing timely was necessary when co-firing DA coal with rice hull. - Highlights: • Digital image technique was used to monitor deposits growth process. • A type of four stages mode of ash deposit growth was presented. • The heat flux of ash deposits fit a three-stage mode. • The addition of rice hull increased the porosity of deposits

  3. Identification of admixture for pelletization and strength enhancement of sintered coal pond ash aggregate through statistically designed experiments

    International Nuclear Information System (INIS)

    Highlights: • Sintered aggregate using pond ash from lignite and bituminous coal source. • Identification of admixtures and its dosage through design of experiments. • Clay, bentonite and kaolinite as binders enhance the strength of aggregate. • Use of calcium hydroxide with clay binder enhanced pelletization efficiency. • Use of borax with clay binders enhanced the strength of aggregate. - Abstract: Statistically designed experiments using Response Surface Methodology have been undertaken to identify the parameters influencing manufacturing process and properties of aggregate using coal pond ash (generated from bituminous and lignite coal sources). Based on the preliminary studies, Ca(OH)2 and borax have been identified as pelletization and strength enhancing admixture respectively. Pelletization efficiency of bituminous and lignite pond ash increased with an increase in binder and Ca(OH)2 dosage to 20–98% and 50–98% respectively, with proportionate quantity of water. Sintering has been used as a hardening method with temperature range of 900 °C and 1100 °C for a duration range of 45–120 min. Phase composition and sintered microstructure of aggregate has been reported using X-ray diffraction and scanning electron microscopy respectively. The ten percent fines value of aggregate with clay binder was 5.5 tonne as against a value of 4.5 tonne with aggregate with bentonite binder. Among the binders studied, bentonite resulted in high volume utilization of pond ash, i.e. up to 88%

  4. The occurrence of hazardous volatile elements and nanoparticles in Bulgarian coal fly ashes and the effect on human health exposure

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Luis F.O., E-mail: lfsoliveira@univates.br [Centro Universitario Univates, Pro Reitoria de Pesquisa Estensao e Pos Graduacao, Programa de Pos Graduacao Ambiente e Desenvolvimento (Brazil); Environmental Science and Nanotechnology Department, Catarinense Institute of Environmental Research and Human Development - IPADHC, Capivari de Baixo, Santa Catarina (Brazil); DaBoit, Katia [Department of Environmental Medicine, Catarinense Institute of Environmental Research and Human Development - IPADHC, Capivari de Baixo, Santa Catarina (Brazil); Sampaio, Carlos H. [Universidade Federal do Rio Grande do Sul, Escola de Engenharia, Departamento de Metalurgia, Centro de Tecnologia, Av. Bento Goncalves, 9500, Bairro Agronomia, CEP: 91501-970, Porto Alegre - RS (Brazil); Jasper, Andre [Centro Universitario Univates, Pro Reitoria de Pesquisa Estensao e Pos Graduacao, Programa de Pos Graduacao Ambiente e Desenvolvimento (Brazil); Andrade, Maria L. [Department of Plant Biology and Soil Science, University of Vigo, 36310 Vigo (Spain); Kostova, Irena J. [Sofia University ' St. Kliment Ohridski' , Department of Geology, Paleontology and Fossil Fuels, 15, Tzar Osvoboditel Blvd., 1000 Sofia (Bulgaria); and others

    2012-02-01

    Low-rank, high-mineral matter Bulgarian coals were studied using a variety of chemical, optical, and electron beam methods. The larger fly ash carbon phases include charred carbons in contrast to coked carbons present in the fly ashes of bituminous-coal-derived fly ashes. Nanoscale carbons include multi-walled carbon nanotubes (MWCNTs) encapsulating Hg, Se, and As, among other elements. In addition to the glass which dominates the fly ash, relatively coarse 'rock fragments', consisting of an unmelted to partially melted core surrounded by a glassy rim, are present in the fly ash. Nano-scale minerals can contain hazardous elements and, along with metal-bearing multiwalled nanotubes, can be a path for the entry of hazardous particles into the lungs and other organs. Highlights: Black-Right-Pointing-Pointer We model Bulgarian power plants which have regulated minerals nanoparticles can contain hazardous elements. Black-Right-Pointing-Pointer We study changes in the level of information about nanominerals importance and the effect on human health exposure. Black-Right-Pointing-Pointer Increasing information will increase quality if power plants procedures are similar.

  5. Temperature effect on the pressure drop across the cake of coal gasification ash formed on a ceramic filter

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.H.; Liang, Y.; Sakong, K.M.; Choi, J.H.; Bak, Y.C. [Gyeongsang National University, Jinju (Republic of Korea). Dept. of Biology & Chemical Engineering

    2008-01-15

    In order to predict the pressure drop across the cake of coal gasification (CG) ash formed on ceramic filter, an empirical equation was developed taking into account several factors, such as the face velocity, ash load, shape factor and size of particles, and especially the operating temperature. The hot air stream of well classified fine particles of CG ash was simulated as the syngas derived from the coal gasification process. The pressure drop behavior and cleaning efficiency of the filter were carefully investigated within the temperature range from room temperature to 673 K. The pressure drop across the ash cake was dominantly governed by the air viscosity, which increased with temperature. It was well expressed by the previously reported-empirical equation (J.H. Choi, Y.C. Bak, H.J. Jang, J.H. Kim, and J.H. Kim, Korean J. Chern. Eng., 21(3) (2004) 726.) with the modification of the viscosity term in the equation for different temperatures. The residual pressure drop rate across the ash cake also increased while the cleaning efficiency of the ceramic filter decreased as temperature increased.

  6. Extractive de-sulfurization and de-ashing of high sulfur coals by oxidation with ionic liquids

    International Nuclear Information System (INIS)

    Highlights: • Extractive de-sulfurization and de-ashing process for cleaning high sulfur coals. • The process removes inorganic as well as organic sulfur components from high sulfur coals. • The process has less risk to chemists and other surroundings. - Abstract: The environmental consequences of energy production from coals are well known, and are driving the development of desulfurization technologies. In this investigation, ionic liquids were examined for extractive desulfurization and de-ashing in industrially important high sulfur sub-bituminous Indian coals. The ionic liquids, namely, 1-n-butyl-3-methylimidazolium tetrafluoroborate (IL1) and 1-n-butyl 3-methylimidazolium chloride (IL2) were employed for desulfurization of a few Indian coal samples in presence of HCOOH/H2O2 and V2O5. Results show the maximum removal of 50.20% of the total sulfur, 48.00% of the organic sulfur, and 70.37 wt% of the ash in this process. The ionic liquids were recovered and subsequently used for further desulfurization. FT-IR spectra reveal the transformation of organic sulfur functionalities into the sulfoxides (S=O) and sulfones (-SO2) due to the oxidative reactions. The sulfate, pyrite and sulfides (aryls) signals in the near edge X-ray absorption fine structure (NEXAFS) of the oxidized coal samples showed sulfur transformation during the desulfurization process. The study demonstrates the removal of significant amount of inorganic as well as organic sulfur (aryls) components from the original high sulfur coal samples to make them cleaner

  7. Minerals in the Ash and Slag from Oxygen-Enriched Underground Coal Gasification

    Directory of Open Access Journals (Sweden)

    Shuqin Liu

    2016-03-01

    Full Text Available Underground coal gasification (UCG is a promising option for the recovery of low-rank and inaccessible coal resources. Detailed mineralogical information is essential to understand underground reaction conditions far from the surface and optimize the operation parameters during the UCG process. It is also significant in identifying the environmental effects of UCG residue. In this paper, with regard to the underground gasification of lignite, UCG slag was prepared through simulation tests of oxygen-enriched gasification under different atmospheric conditions, and the minerals were identified by X-Ray diffraction (XRD and a scanning electron microscope coupled to an energy-dispersive spectrometer (SEM-EDS. Thermodynamic calculations performed using FactSage 6.4 were used to help to understand the transformation of minerals. The results indicate that an increased oxygen concentration is beneficial to the reformation of mineral crystal after ash fusion and the resulting crystal structures of minerals also tend to be more orderly. The dominant minerals in 60%-O2 and 80%-O2 UCG slag include anorthite, pyroxene, and gehlenite, while amorphous substances almost disappear. In addition, with increasing oxygen content, mullite might react with the calcium oxide existed in the slag to generate anorthite, which could then serve as a calcium source for the formation of gehlenite. In 80%-O2 UCG slag, the iron-bearing mineral is transformed from sekaninaite to pyroxene.

  8. Surface and bulk characterization of an ultrafine South African coal fly ash with reference to polymer applications

    Science.gov (United States)

    van der Merwe, E. M.; Prinsloo, L. C.; Mathebula, C. L.; Swart, H. C.; Coetsee, E.; Doucet, F. J.

    2014-10-01

    South African coal-fired power stations produce about 25 million tons of fly ash per annum, of which only approximately 5% is currently reused. A growing concern about pollution and increasing landfill costs stimulates research into new ways to utilize coal fly ash for economically beneficial applications. Fly ash particles may be used as inorganic filler in polymers, an application which generally requires the modification of their surface properties. In order to design experiments that will result in controlled changes in surface chemistry and morphology, a detailed knowledge of the bulk chemical and mineralogical compositions of untreated fly ash particles, as well as their morphology and surface properties, is needed. In this paper, a combination of complementary bulk and surface techniques was explored to assess the physicochemical properties of a classified, ultrafine coal fly ash sample, and the findings were discussed in the context of polymer application as fillers. The sample was categorized as a Class F fly ash (XRF). Sixty-two percent of the sample was an amorphous glass phase, with mullite and quartz being the main identified crystalline phases (XRD, FTIR). Quantitative carbon and sulfur analysis reported a total bulk carbon and sulfur content of 0.37% and 0.16% respectively. The spatial distribution of the phases was determined by 2D mapping of Raman spectra, while TGA showed a very low weight loss for temperatures ranging between 25 and 1000 °C. Individual fly ash particles were characterized by a monomodal size distribution (PSD) of spherical particles with smooth surfaces (SEM, TEM, AFM), and a mean particle size of 4.6 μm (PSD). The BET active surface area of this sample was 1.52 m2/g and the chemical composition of the fly ash surface (AES, XPS) was significantly different from the bulk composition and varied considerably between spheres. Many properties of the sample (e.g. spherical morphology, small particle size, thermal stability) appeared

  9. The Impact of Coal Combustion Fly Ash Used as a Supplemental Cementitious Material on the Leaching of Constituents from Cements and Concretes

    Science.gov (United States)

    The objective of this report is to compare the leaching of portland cement-based materials that have been prepared with and without coal combustion fly ash to illustrate whether there is evidence that the use of fly ash in cement and concrete products may result in increased leac...

  10. Weathering behaviour of overburden-coal ash blending in relation to overburden management for acid mine drainage prevention in coal surface mine

    International Nuclear Information System (INIS)

    Potentially acid forming (PAF) materials are encapsulated with non-acid forming materials (NAF) in order to prevent acid mine drainage (AMD) in surface coal mines. NAF compaction techniques with fly and bottom ashes from coal-fired power plants are used in mines with limited amounts of NAF materials. This study investigated the weathering behaviour of blended overburden and coal combustion ash in laboratory conditions. Free draining column leach tests were conducted on different blending schemes. The weathering process was simulated by spraying the samples with de-ionized water once per day. The leachates were then analyzed using X-ray diffraction and fluorescence analyses in order to identify the mineral composition of the samples over a 14 week period. Results of the study indicated that the weathering process plays a significant role in controlling infiltration rates, and may increase the capability of capping materials to prevent infiltration into PAF materials. Fly- and bottom-ash additions improved the performance of the encapsulation materials. 3 refs., 4 tabs., 2 figs.

  11. Weathering behaviour of overburden-coal ash blending in relation to overburden management for acid mine drainage prevention in coal surface mine

    Energy Technology Data Exchange (ETDEWEB)

    Gautama, R.S.; Kusuma, G.J.; Lestari, I.; Anggana, R.P. [Bandung Inst. Teknologi (Indonesia). Dept. of Mining Engineering, Faculty of Mining and Petroleum Engineering

    2010-07-01

    Potentially acid forming (PAF) materials are encapsulated with non-acid forming materials (NAF) in order to prevent acid mine drainage (AMD) in surface coal mines. NAF compaction techniques with fly and bottom ashes from coal-fired power plants are used in mines with limited amounts of NAF materials. This study investigated the weathering behaviour of blended overburden and coal combustion ash in laboratory conditions. Free draining column leach tests were conducted on different blending schemes. The weathering process was simulated by spraying the samples with de-ionized water once per day. The leachates were then analyzed using X-ray diffraction and fluorescence analyses in order to identify the mineral composition of the samples over a 14 week period. Results of the study indicated that the weathering process plays a significant role in controlling infiltration rates, and may increase the capability of capping materials to prevent infiltration into PAF materials. Fly- and bottom-ash additions improved the performance of the encapsulation materials. 3 refs., 4 tabs., 2 figs.

  12. Exploring metal detoxification and accumulation potential during vermicomposting of Tea factory coal ash: sequential extraction and fluorescence probe analysis.

    Science.gov (United States)

    Goswami, Linee; Pratihar, Sanjay; Dasgupta, Suman; Bhattacharyya, Pradip; Mudoi, Pronab; Bora, Jayanta; Bhattacharya, Satya Sundar; Kim, Ki Hyun

    2016-01-01

    Metal contamination from coal ashes (CAs) is widely recognized as a significant environmental concern. To learn more about metal detoxification and accumulation potential of earthworm species, metal-rich tea factory coal ashes (TFCA) were fed to Eisenia fetida and Lampito mauritii by employing a fluorescent tag detection method. Fascinatingly, on feeding fluorescence probed Zn and Cd along with cow dung to Eisenia fetida, the detection of the gut-proteins with a molecular mass higher than 100 kDa was a distinct evidence of metal binding. Significant increases were observed in the content of humified organic C [humic acid (HAC) and fulvic acid C (FAC)] and degree of humification during vermicomposting. Concurrently, considerably large amount of toxic metals (Cr, Cd, Pb, and Zn) was transformed from exchangeable to recalcitrant (organic matter and mineral bound) fractions. Moreover, total metal concentrations were reduced with high removal efficiency upon vermicomposting. PMID:27456167

  13. Exploring metal detoxification and accumulation potential during vermicomposting of Tea factory coal ash: sequential extraction and fluorescence probe analysis

    Science.gov (United States)

    Goswami, Linee; Pratihar, Sanjay; Dasgupta, Suman; Bhattacharyya, Pradip; Mudoi, Pronab; Bora, Jayanta; Bhattacharya, Satya Sundar; Kim, Ki Hyun

    2016-07-01

    Metal contamination from coal ashes (CAs) is widely recognized as a significant environmental concern. To learn more about metal detoxification and accumulation potential of earthworm species, metal-rich tea factory coal ashes (TFCA) were fed to Eisenia fetida and Lampito mauritii by employing a fluorescent tag detection method. Fascinatingly, on feeding fluorescence probed Zn and Cd along with cow dung to Eisenia fetida, the detection of the gut-proteins with a molecular mass higher than 100 kDa was a distinct evidence of metal binding. Significant increases were observed in the content of humified organic C [humic acid (HAC) and fulvic acid C (FAC)] and degree of humification during vermicomposting. Concurrently, considerably large amount of toxic metals (Cr, Cd, Pb, and Zn) was transformed from exchangeable to recalcitrant (organic matter and mineral bound) fractions. Moreover, total metal concentrations were reduced with high removal efficiency upon vermicomposting.

  14. Investigation of the chemical composition of ash generated from Kosovo lignite and the possibility for biological land reclamation on ash dumps

    Energy Technology Data Exchange (ETDEWEB)

    Urosevic, D.; Filipovic, R. [Mining Institute Belgrade, Belgrade (Yugoslavia)

    1997-07-01

    This paper presents the results of investigation of the chemical composition and other properties of ash generated in the coal combustion process in the coal-fired power plants Kosovo, in order to determine the possibilities for biological land reclamation on ash dumps and other degraded soil surfaces. It was established that a certain chemical composition of ash has a beneficial effect on biological land reclamation of ash dumps, thus protecting the environment (i.e. the area surrounding the ash dumps), against pollution. It was concluded that, because of the high percentage of calcium and other earth-alkaline and toxic elements, the ash should not be used as substitution for agricultural production. Ash dumps in Kosovo are not so susceptible to erosion since CaO{sub 3} acts as a binding component. 22 refs., 7 tabs.

  15. Reuse of ash coal in the formulation of mortars; Reaproveitamento de cinzas de carvao mineral na formulacao de argamassas

    Energy Technology Data Exchange (ETDEWEB)

    Siqueira, J.S.; Souza, C.A.G.; Souza, J.A.S., E-mail: jacilene_s@yahoo.com.br, E-mail: celioag@ufpa.br, E-mail: jass@ufpa.br [Programa de Pos Graduacao em Engenharia Quimica, Universidade Federal do Para, UFPA/PPEQ, Belem, PA (Brazil)

    2012-04-15

    This paper aims to study the ash incorporation from the combustion of coal in fluidized bed boilers, in production of mortar, replacing part of cement. Specimens were prepared using Portland cement to the specifications CPII-E-32 of normal characteristics and classification of sand below 100 mesh. Blends in the 4:1 ratio, that is, 4 parts of aggregate to 1 part of cement, with insertion of ashes in the proportions 0, 10, 20, 30, 40 and 50%. The mortar was developed in mixing and casting was made in a mold of 5 cm x 10 cm. The behavior of compressive strength was evaluated after 28 days; the strength decreases with increasing percentage of ash. Additional analysis was carried out by X-ray diffraction, and it was found that the substitution of this waste can be successfully used in mortars with blends of up to 30%. (author)

  16. Coal fly ash-containing sprayed mortar for passive fire protection of steel sections

    Directory of Open Access Journals (Sweden)

    Vilches, L. F.

    2005-09-01

    Full Text Available The present article addresses the possible use of coal fly ash as the chief component of sprayed mortars to fireproof steel structures. A pilot wet-mix gunning rig was specifically designed and built to spray different pastes on to sheet steel and sections with different surface/volume ratios. After gunning, the specimens were placed in a furnace and subjected to standard fire resistance testing. Product fire resistance was calculated from the test results. The mortar used in this study, with a high fly ash content, was found to have acceptable mechanical properties as well as afire resistance potential comparable to those of commercial passive fire protection products.

    En este artículo se estudia el posible uso de las cenizas volantes procedentes de la combustión del carbón como constituyente principal de morteros que pueden ser proyectados sobre estructuras metálicas, para protegerlas contra el fuego. Con objeto de estudiar el proceso de proyección, se ha construido una planta piloto de gunitado por vía húmeda. La pasta se ha proyectado sobre placas metálicas y perfiles metálicos con diferentes relaciones superficie/volumen. Tras el gunitado, las probetas proyectadas se colocan en un horno y se someten a un programa de calentamiento según la norma de resistencia al fuego. A partir de los datos obtenidos se ha podido realizar una estimación de la resistencia al fuego del producto. Los resultados muestran que el material proyectado usado en este estudio, que contiene una alta proporción de cenizas volantes, tiene unas propiedades mecánicas aceptables y unas características potenciales de resistencia al fuego comparables a las de otros productos comerciales utilizados en la protección pasiva contra el fuego.

  17. The effects of alkaline dosage and Si/Al ratio on the immobilization of heavy metals in municipal solid waste incineration fly ash-based geopolymer.

    Science.gov (United States)

    Zheng, Lei; Wang, Wei; Shi, Yunchun

    2010-04-01

    The present research explored the application of geopolymerization for the immobilization and solidification of municipal solid waste incineration (MSWI) fly ash. The influence of alkaline activator dosage and Si/Al molar ratio on the compressive strength and microstructure of MSWI fly ash-based geopolymer was investigated. A geopolymer with the highest strength was identified to occur at an intermediate alkaline activator dosage and Si/Al ratio, and the optimal Na/MSWI fly ash and Si/Al molar ratio was close to 2.8 mol kg(-1) and 2.0, respectively. IR spectra showed that higher alkaline activator dosage enhanced the structural disruption of the original aluminosilicate phases and a higher degree of polymerization of the geopolymer networks. At low Si/Al ratio, there was an increasing number of tetrahedral Al incorporating into the silicate backbone. As the Na/MSWI fly ash ratio increased, the microstructure changed from containing large macropores to more mesopores and micropores, indicating that more geopolymers are formed. Furthermore, the pore volume distribution of geopolymers was observed to shift to larger pores as the Si/Al ratio increased, which suggests that the soluble silicon content serves to reduce the amount of geopolymers. Heavy metal leaching was successfully elucidated using the first-order reaction/reaction-diffusion model. Combining the results from the microstructure of samples with the kinetic analysis, the immobilization mechanism of Cr, Cu, and Zn was inferred in this study. The methodologies described could provide a powerful set of tools for the systematic evaluation of element release from geopolymers.

  18. Characterization of fly ash from low-sulfur and high-sulfur coal sources: Partitioning of carbon and trace elements with particle size

    Science.gov (United States)

    Hower, J.C.; Trimble, A.S.; Eble, C.F.; Palmer, C.A.; Kolker, A.

    1999-01-01

    Fly ash samples were collected in November and December of 1994, from generating units at a Kentucky power station using high- and low-sulfur feed coals. The samples are part of a two-year study of the coal and coal combustion byproducts from the power station. The ashes were wet screened at 100, 200, 325, and 500 mesh (150, 75, 42, and 25 ??m, respectively). The size fractions were then dried, weighed, split for petrographic and chemical analysis, and analyzed for ash yield and carbon content. The low-sulfur "heavy side" and "light side" ashes each have a similar size distribution in the November samples. In contrast, the December fly ashes showed the trend observed in later months, the light-side ash being finer (over 20 % more ash in the -500 mesh [-25 ??m] fraction) than the heavy-side ash. Carbon tended to be concentrated in the coarse fractions in the December samples. The dominance of the -325 mesh (-42 ??m) fractions in the overall size analysis implies, though, that carbon in the fine sizes may be an important consideration in the utilization of the fly ash. Element partitioning follows several patterns. Volatile elements, such as Zn and As, are enriched in the finer sizes, particularly in fly ashes collected at cooler, light-side electrostatic precipitator (ESP) temperatures. The latter trend is a function of precipitation at the cooler-ESP temperatures and of increasing concentration with the increased surface area of the finest fraction. Mercury concentrations are higher in high-carbon fly ashes, suggesting Hg adsorption on the fly ash carbon. Ni and Cr are associated, in part, with the spinel minerals in the fly ash. Copyright ?? 1999 Taylor & Francis.

  19. Hard Coal Fly Ash and Silica-Effect of Fine Particulate Matter Deposits on Brassica chinensis

    Directory of Open Access Journals (Sweden)

    Christian Ulrichs

    2009-01-01

    Full Text Available Problem statement: One focus in recent atmospheric pollution research is on fine Particle Matter (PM, especially as result of increasing traffic and anthropogenic activity in urban areas. Here, the impact on animal and human health has been in the center of many studies. Despite the fact that PM depositions can affect plants on the long term, there are only few studies about the impact on plants conducted. Approach: Therefore we studied the impact of PM on plants, using naturally occurring silica dusts (diatomaceous earth and hard Coal Fly Ash (CFA from burning processes. Dusts were applied onto Brassica chinensis L. using a simple duster (covering upper leaf surfaces or electrostatically (covering leaf upper and -underside. Results: Main components of the tested CFA are SO42-, K, Ca and NH4+. The pH value of eluates was found to be around 9.5 in CFA and 5.7 in silica. B. chinensis was insensitive towards the high pH and showed no growth reduction when grown in silica or CFA substrate. PM deposition on leaf surfaces results through shading in a reduced photosynthetic activity. The reduction is relatively higher at higher light intensities. Photosynthesis stays reduced after removal of silica PM from leaf surfaces. We assume that stomata get cloaked by small particles and that silica absorbs lipids from the epicuticle resulting in a general stress reaction. Smaller sized silica particles resulted in a higher reduction of CO2-absorption. Next to particle size is the photosynthesis negatively correlated with exposure time for silica PM. The chlorophyll fluorescence data indicate that dust-covered leaves exhibited significantly lower quantum yield of PS II and a reduced quantum efficiency of PS II and therefore supported the gas exchange data. Conclusion: Reduced photosynthetic performance would be expected to reduce growth and productivity of B. chinensis. In contrast to silica hard coal fly ash

  20. Arsenic remediation of drinking water using iron-oxide coated coal bottom ash

    Energy Technology Data Exchange (ETDEWEB)

    MATHIEU, JOHANNA L.; GADGIL, ASHOK J.; ADDY, SUSAN E.A.; KOWOLIK, KRISTIN

    2010-06-01

    We describe laboratory and field results of a novel arsenic removal adsorbent called 'Arsenic Removal Using Bottom Ash' (ARUBA). ARUBA is prepared by coating particles of coal bottom ash, a waste material from coal fired power plants, with iron (hydr)oxide. The coating process is simple and conducted at room temperature and atmospheric pressure. Material costs for ARUBA are estimated to be low (~;;$0.08 per kg) and arsenic remediation with ARUBA has the potential to be affordable to resource-constrained communities. ARUBA is used for removing arsenic via a dispersal-and-removal process, and we envision that ARUBA would be used in community-scale water treatment centers. We show that ARUBA is able to reduce arsenic concentrations in contaminated Bangladesh groundwater to below the Bangladesh standard of 50 ppb. Using the Langmuir isotherm (R2 = 0.77) ARUBA's adsorption capacity in treating real groundwater is 2.6x10-6 mol/g (0.20 mg/g). Time-to-90percent (defined as the time interval for ARUBA to remove 90percent of the total amount of arsenic that is removed at equilibrium) is less than one hour. Reaction rates (pseudo-second-order kinetic model, R2>_ 0.99) increase from 2.4x105 to 7.2x105 g mol-1 min-1 as the groundwater arsenic concentration decreases from 560 to 170 ppb. We show that ARUBA's arsenic adsorption density (AAD), defined as the milligrams of arsenic removed at equilibrium per gram of ARUBA added, is linearly dependent on the initial arsenic concentration of the groundwater sample, for initial arsenic concentrations of up to 1600 ppb and an ARUBA dose of 4.0 g/L. This makes it easy to determine the amount of ARUBA required to treat a groundwater source when its arsenic concentration is known and less than 1600 ppb. Storing contaminated groundwater for two to three days before treatment is seen to significantly increase ARUBA's AAD. ARUBA can be separated from treated water by coagulation and clarification, which is expected to

  1. Sulfur species leached from pyrite during oxidative desulfurization of coal in alkaline solutions

    Energy Technology Data Exchange (ETDEWEB)

    Stephenson, M.D.; Wheelock, T.D.; Markuszewski, R.

    1983-01-01

    The results indicate that thiosulfate, sulfite, and sulfate are the principal soluble sulfur species produced when coal-derived pyrite leached with a hot alkaline solution containing dissolved oxygen. The distribution of soluble sulfur species in the leachate was found to depend on leaching temperature, oxygen partial pressure, leachant composition, and time of contact. At lower temperatures and oxygen partial pressures and with a short time of contact between the leaching solution and pyrite, the leachate sulfur species were dominated by thiosulfate. However, the leachate also contained significant amounts of sulfite and sulfate. When the temperature, oxygen partial pressure, or time of contact were increased, the proportions of thiosulfate and sulfite decreased and the proportion of sulfate increased. It was observed also that reacted pyrite particles catalyzed the oxidation of thiosulfate to sulfite and sulfate. Consequently when pyrite was oxidized in a stirred reactor for 1 h at elevated temperature and oxygen partial pressure, most of the dissolved sulfur appeared as sulfate and very little as thiosulfate or sulfite. 10 references, 4 figures, 1 table.

  2. Deposit formation in a full-scale pulverized wood-fired power plant with and without coal fly ash addition

    DEFF Research Database (Denmark)

    Wu, Hao; Shafique Bashir, Muhammad; Jensen, Peter Arendt;

    2013-01-01

    temperatures of ~1300oC and ~800oC, respectively. It was found that during pulverized wood combustion, the deposit formation at the hightemperature location was characterized by a slow and continuous growth of deposits followed by the shedding of a large layer of deposits, while the deposit formation......Ash transformation and deposition in a pulverized wood-fired power plant boiler of 800 MWth were studied with and without the addition of coal fly ash. The transient ash deposition behavior was investigated by using an advanced deposit probe system at two different boiler locations with flue gas...... at the low-temperature location showed a slow initial build-up and a stable mass of deposits after approximately 1-5 h. The deposits collected during pulverized wood combustion contained a considerable amount of K2SO4, KCl, and KOH/K2CO3. With the addition of coal fly ash (~4 times of the mass flow of wood...

  3. Removal of sulphates from South African mine water using coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Madzivire, G.; Petrik, L.F. [Western Cape Univ., Bellville (South Africa). Dept. of Chemistry; Gitari, W.M. [Cape Peninsula Univ. of Technology, Cape Town (South Africa). Dept. of Chemistry; Ojumu, T.V. [Cape Peninsula Univ. of Technology, Cape Town (South Africa). Dept. of Chemical Engineering; Misheer, N. [Eskom, Johannesburg (South Africa). Dept. of Research and Innovation

    2010-07-01

    This study investigated the use of alkaline fly ash (FA) produced by South African power stations as a means of neutralizing acid mine drainage South African mines. The mine water has circumneutral pH, low concentrations of iron (Fe) and aluminium (Al), and is rich in calcium (Ca), magnesium (Mg), and sulfate (SO{sub 4}{sup 2-}). The FA was used to remove SO{sub 4}{sup 2-} from the mine water. A geochemical modelling tool was used to investigate the effect of Fe and Al on sulphate removal from NMD when reacted with FA. The study also investigated the mineral phases responsible for the removal of sulphates, Fe, Al and Mn from mine water samples. The samples were analyzed by inductively-coupled plasma-atomic emission mass spectrometry and ion chromatography for cations and anions. Results of the geochemical modelling study showed that the removal of sulphates, Mg, Mn, Al and Fe was significantly influenced by the final pH of the water. When mine water pH was raised to greater than 6, 8, 9, and 11, approximately 100 percent of Al, Fe, Mn and Mg were removed. 7 refs., 6 figs.

  4. OPTIMISATION OF COPPER AND ZINC IONS REMOVAL FROM AQUEOUS SOLUTION BY COAL FLY ASH AS AN ADSORBENT

    Directory of Open Access Journals (Sweden)

    MOYO ,M

    2012-04-01

    Full Text Available Rapid urbanization and industrialization of our world has led to accumulation of enormous number of contaminants in our environment. Heavy metal ions hold a superlative position in that list and are responsible for contaminating soil, air and water in many parts of the world. Adsorption technology is emerging as a sustainable effective solution. The possibility of using Coal fly ash as an alternative adsorbent for divalent metal ions (Zn2+, Cu2+ removal from simulated solutions was studied. The coal fly ash was characterised by Brunauer Emmet Teller (BET, X-ray diffraction (XRD, X-ray Fluorescence Spectroscopy (XRF and Fourier transforminfrared (FT-IR. Optimum adsorption conditions were determined as a function of pH, adsorbent dosage and contact time for Zn2+ and Cu2+ removal. The adsorption of metal ions was found to be pH dependant.Equilibrium data fitted well to the Freundlich model with R2 values as 0.9932, 0.9971 for Cu2+, Zn2+, respectively. The study showed that disposed coal fly ash could be used as an efficient adsorbent material for the removal of metal ions from aqueous solution.

  5. Statistical Analysis of the Tensile Strength of Coal Fly Ash Concrete with Fibers Using Central Composite Design

    Directory of Open Access Journals (Sweden)

    Marinela Barbuta

    2015-01-01

    Full Text Available The influence of coal fly ash and glass fiber waste on the tensile strength of cement concrete was studied using central composite design. Coal fly ash was used to replace 10% of the cement in the concrete mix. Glass fiber was added to improve the tensile properties of the concrete in different dosages and lengths. In total, 14 mixes were investigated, one only with 10% coal fly ash replacement of cement and the other thirteen were determined by the experimental design. Using analysis of variance, the order of importance of the variables was established for each property (flexural strength and split tensile strength. From the nonlinear response surfaces, it was found that higher values of flexural strength were obtained for fibers longer than 12 mm and at a dosage of 1-2%. For split tensile strength, higher values were obtained for fibers with a length of 19–28 mm and at a dosage of 1–1.5%.

  6. Disintegration of excess sludge enhanced by a combined treatment of gamma irradiation and modified coal fly ash

    Science.gov (United States)

    Xiang, Yulin; Wang, Lipeng; Jiao, Yurong

    2016-03-01

    In order to improve the disintegration performance and accelerate the disintegration rate of excess sludge, the individual and combined influences of γ-ray irradiation and modified coal fly ash treatment on the disintegration of excess sludge were investigated based on physicochemical properties of excess sludge. The changes in constituents of excess sludge were examined by means of UV/vis spectra and SEM images. The results showed that the disintegration performance of excess sludge was effectively improved by gamma ray irradiation in the presence of modified coal fly ash. A new band from 250 nm to 290 nm appeared on all irradiated sludge samples. The SEM images illustrated the cells surfaces of the sludge by the combined treatment were disfigured. The SCOD, soluble carbohydrate and protein from sludge supernatant increased obviously with increasing modified CFA dosage from 0 to 0.2 g ml-1 and dose from 0 to 10 kGy. The sludge SRF and filter cake moisture declined significantly, and the filtration speed was faster. In conclusion, γ-ray irradiation-modified coal fly ash pretreatment is an effective method to disintegrate excess sludge.

  7. The Utilization of Bottom Ash Coal for Briquette Products by Adding Teak Leaves Charcoal, Coconut Shell Charcoal, and Rice Husk Charcoal

    Directory of Open Access Journals (Sweden)

    Syafrudin Syafrudin

    2015-01-01

    Full Text Available The limitations of the availability of energy sources especially fuel oil has become a serious threat for the society. The use of coal for energy source as the replacement of fuel oil, in one hand, is very profitable, but on the other hand, will cause problem which is the coal ash residue. This coal ash is a by-product of coal combustion. This coal ash contains bottom ash. Through this observation, the bottom ash can be processed to be charcoal if added by teak leaves, coconut shell, and rice husk. Also, this observation needs to add binder materials for further processing in order to form briquette. It can be used as alternative fuel, the utilization of bottom ash and biomass will give positive impact to the environment. This observation was conducted by using compositions such as bottom ash, teak leaves, coconut shell, and rice husk. The treatment was using comparison 100%:0% ; 80%:20% ; 60%:40% ; 50%:50% ; 40%:60% ; 20%:80% ; 0%:100%. The result that the best briquette was on the composition of 20% bottom ash : 80% coconut shell. The characteristic values from that composition were moisture content of 3.45%, ash content of 17,32%, calorific value of 7.945,72 Cal/gr, compressive strength of 2,18 kg/cm2, level of CO of 105 mg/m3, and heavy metals Cu of 29,83 µg/g and  Zn 32,99 µg/g. The characteristic value from each briquette composition treatment showed that the increasing usage proportion of biomass as added material for briquette was able to increase its moisture content and calorific value. Besides, it is also able to decrease its ash content and compressive strength

  8. Detection of rare earth elements in Powder River Basin sub-bituminous coal ash using laser-induced breakdown spectroscopy (LIBS)

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Phuoc [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United State; Mcintyre, Dustin [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United State

    2015-10-01

    We reported our preliminary results on the use of laser-induced breakdown spectroscopy to analyze the rare earth elements contained in ash samples from Powder River Basin sub-bituminous coal (PRB-coal). We have identified many elements in the lanthanide series (cerium, europium, holmium, lanthanum, lutetium, praseodymium, promethium, samarium, terbium, ytterbium) and some elements in the actinide series (actinium, thorium, uranium, plutonium, berkelium, californium) in the ash samples. In addition, various metals were also seen to present in the ash samples

  9. Synthesis of zeolite A from coal fly ash using ultrasonic treatment--A replacement for fusion step.

    Science.gov (United States)

    Ojumu, Tunde V; Du Plessis, Pieter W; Petrik, Leslie F

    2016-07-01

    The synthesis of zeolites from fly ash has become an increasingly promising remedy to the crisis of coal fly ash production and disposal in South Africa. In recent studies, South African fly ash was proven to be a suitable feedstock for the synthesis of essential industrially used zeolite A. However, the process involves a costly energy intensive step whereby fly ash is fused at high temperatures, which may make the process economically unattractive on a large scale. The aim of this study is to investigate the possibility of replacing high temperature fusion with less energy intensive sonochemical treatment for the synthesis of zeolite A. Sonochemical treatment was first thought possible due to the violent cavitation caused by high intensity sonication. The results of the study showed that fusion can be replaced by 10 min of high intensity sonication. The incorporation of sonication also consequently reduced the crystallization temperature of the process making it possible to synthesize a pure phase zeolite A at lower temperatures and reduced times. This study effectively developed a novel process to replace the energy intensive fusion step with a short, easy and inexpensive treatment. Scale up of this synthesis approach may proffer a promising alternative option to the anticipated energy demand of the synthesis of fly ash-based zeolite with fusion method. PMID:26964958

  10. Synthesis of Zeolite from Coal Fly Ash: Its Application as Water Sorbent

    Directory of Open Access Journals (Sweden)

    Prasert Pavasant

    2010-03-01

    Full Text Available Coal fly ash (CFA was used as raw material for zeolite synthesis by fusion method. In detail, it was mixed with NaOH (with ratio of 2.25 and treated under various temperatures. Synthesized zeolite was characterized using various techniques i.e. X-rayfluorescence (XRF, X-ray diffraction (XRD, and BET surface area analysis. It was found that the surface area of synthesized zeolite were in the range of 49.407-69.136 m2/g depending on the preparing condition, compared to the surface area of CFA about 17.163 m2/g. In addition, according to the XRD result, it was proven that the form of zeolite was Sodium Aluminum Silicate Hydrate (1.08Na2O.Al2O3.1.68SiO2.1.8H2O. The synthesized zeolite was then applied as water sorbent to remove water from ethanol solution (95%. The testing results revealed that the optimal fusion temperature was 450.C, which provided maximum percentage of water removal from ethanol solution (from 95% ethanol to 99.25% ethanol. For comparison, commercial-grade molecular sieve was also tested and was found to increase ethanol concentration from 95% to 99.61%. Hence, it is concluded that our synthesized zeolite provides comparable performance to the commercial-grade molecular sieve.

  11. Glass ceramic foams from coal ash and waste glass: production and characterisation

    Energy Technology Data Exchange (ETDEWEB)

    Wu, J.P.; Boccaccini, A.R.; Lee, P.D.; Kershaw, M.J.; Rawlings, R.D. [University of London at Imperial College of Science Technology & Medicine, London (United Kingdom)

    2006-02-01

    Lightweight glass ceramic foams have been produced from a mixture of silicate wastes, namely 20 wt-% coal pond ash and 80 wt-% bottle glass cullet. A powder sintering route with the incorporation of 2 wt-% SiC as foaming agent was used. The pore morphology achieved under different sintering conditions was investigated in detail using X-ray microtomography. The apparent density of the foams ranged from 0.2 to 0{center_dot}4 g cm{sup -3}, and the porosity ranged from 70 to 90%. Other variables, such as pore wall thickness, pore size and roundness, all behaved consistently with sintering temperature. The optimum sintering temperature was found to be in the range 1000-1050{sup o}C, at which porosity was about 75% and was the most uniform. Foams produced under this condition exhibit satisfactory compressive strength of about 1.5 MPa and show relatively high thermal shock resistance, with compressive strength gradually decreasing as quenching temperature increases.

  12. Coal fly ash as a source of iron in atmospheric dust.

    Science.gov (United States)

    Chen, Haihan; Laskin, Alexander; Baltrusaitis, Jonas; Gorski, Christopher A; Scherer, Michelle M; Grassian, Vicki H

    2012-02-21

    Anthropogenic coal fly ash (FA) aerosol may represent a significant source of bioavailable iron in the open ocean. Few measurements have been made that compare the solubility of atmospheric iron from anthropogenic aerosols and other sources. We report here an investigation of iron dissolution for three FA samples in acidic aqueous solutions and compare the solubilities with that of Arizona test dust (AZTD), a reference material for mineral dust. The effects of pH, simulated cloud processing, and solar radiation on iron solubility have been explored. Similar to previously reported results on mineral dust, iron in aluminosilicate phases provides the predominant component of dissolved iron. Iron solubility of FA is substantially higher than of the crystalline minerals comprising AZTD. Simulated atmospheric processing elevates iron solubility due to significant changes in the morphology of aluminosilicate glass, a dominant material in FA particles. Iron is continuously released into the aqueous solution as FA particles break up into smaller fragments. These results suggest that the assessment of dissolved atmospheric iron deposition fluxes and their effect on the biogeochemistry at the ocean surface should be constrained by the source, environmental pH, iron speciation, and solar radiation.

  13. Purification of oily wastewater in thermal power plant by coal fly ash

    Institute of Scientific and Technical Information of China (English)

    刘仁龙; 陈维; 刘清才

    2009-01-01

    The removal of oil from oily wastewater in thermal power plant by coal fly ash(CFA) was investigated. It contained about 2.5 g/L of mineral oil,which had to be treated efficiently before it was discharged. The experiments were carried out as a function of different initial concentrations of oil,mass dosage,contact time and pH value to obtain the optimum conditions for the removal of oil from oily wastewater. The experimental results show that CFA presents the most suitable conditions for the removal of oil from waste-water at a dosage of CFA 2.5 g/L,15 min of contact time and a pH value of 4.8. The adsorption process is performed with almost 96% of oil removal from wastewater. The kinetic data meet the second-order kinetic model. The Langmuir and Freundlich adsorption models were applied to describing the experimental isotherms and isotherm constants. The equilibrium data fit very well with the Freundlich model.

  14. Layer-by-Layer Assembly and Photocatalytic Activity of Titania Nanosheets on Coal Fly Ash Microspheres

    Directory of Open Access Journals (Sweden)

    Xing Cui

    2014-01-01

    Full Text Available In order to address the problem with titania distribution and recovery, series of Ti0.91O2/CFA photocatalysts (Ti0.91O2/CFA-n, n=2,4,6, and 8 were fabricated by assembling Ti0.91O2 nanosheets on coal fly ash (CFA microspheres via the layer-by-layer assembly (LBLA process and characterized by scanning electron microscopy (SEM, X-ray diffraction analysis (XRD, N2-sorption, and ultraviolet-visible absorption (UV-vis techniques. The SEM images and UV-vis spectra illustrated that Ti0.91O2 nanosheets were immobilized successfully on the CFA by the LBLA approach and changed the characteristics of CFA noticeably. The photocatalytic activity of Ti0.91O2/CFA was evaluated by the photodegradation of methylene blue (MB under UV irradiation. The results demonstrated that Ti0.91O2/CFA-6 showed the best photocatalytic activity among the series of Ti0.91O2/CFA irradiated for 60 min, with a decoloration rate above 43%. After photocatalysis, the Ti0.91O2/CFA could be easily separated and recycled from aqueous solution and Ti0.91O2 nanosheets were still anchored on the CFA.

  15. Improvement of soft ground using solidified coal ash and its effects on the marine environment.

    Science.gov (United States)

    Kimura, M; Nishizawa, T; Kotera, H; Katakura, N

    2000-09-15

    This paper presents some research results pertaining to the application of solidified coal ash (SCA) for improving the stability of soft ground. The results pertain to the physical properties of SCA required for use as an alternative to sand in sand compaction piles (SCPs), and the assessment of possible environmental impacts resulting from construction of SCA piles in marine environments. The results of field tests indicate that the physical properties of SCA (permeability, internal friction angle, and grain-size distribution) are favorable for use in soil improvement applications. Also, the results show that SCA is sufficiently suitable as an alternative to sand in SCPs, although SCA piles cannot be compacted to the same extent as sand piles. Finally, test results showed no adverse environmental impacts on natural benthos resulting from placement of SCA piles in marine environments. Thus, the results of this study confirm that SCA is a viable alternative material to sand in SCPs that are used for ground improvement in marine environments, and that large quantities of SCA may be required for such applications resulting in an alternative use for an otherwise waste material. PMID:10936539

  16. Treatment (recycling) of wastes at Tohoku Electric Power Company. Production of oil from waste plastics by using supercritical water, continuous decomposition of fluorocarbon by hydrothermal reaction, manufacture of coal ash sand and its utilization to asphalt road; Tohoku Denryoku no haikibutsu no shori (recycle). Chorinkaisui ni yoru hai plastic no yuka, suinetsu hanno ni yoru freon renzoku bunkai, sekitanbai suna no seizo to asphalt doro eno riyo

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-10-01

    This paper introduces the captioned subjects regarding research and development of waste recycling systems executed at Tohoku Electric Power Company. With regard to production of oil from waste plastics in supercritical water, fundamental tests have been carried out in laboratory scale, and a continuous oil producing equipment (with a treatment capacity of 500 kg per day) was developed and installed based on the results therefrom. The equipment is under tests and operation now. In the research of fluorocarbon decomposition, a continuous fluorocarbon decomposing equipment was developed. The equipment utilizes hydrolytic capability possessed by high-temperature and high-pressure alkaline water to decompose fluorocarbon only by delivering under pressure a fluid mixture composed of fluorocarbon and aqueous alkaline solution into a heated fine reaction tube. The tests have verified that the decomposition is possible at 99.99% or higher at a reaction temperature of 240 deg C. In the effort of developing an effective coal ash utilization technology, a technology was developed, by which sand particles (coal ash sand) are manufactured by adding cement into coal ash, and granulating the mixture. The result of the research performed by the Tohoku Technology Office of the Ministry of Construction and Taisei Rotec Corp. proved effectiveness of the coal ash sand as a material to prevent rutting on asphalt pavement. 10 figs.

  17. Natural radioactivity of coal and fly ash at the Nikola Tesla B TPP

    OpenAIRE

    Kisić Dragica M.; Miletić Saša R.; Radonjić Vladimir D.; Radanović Sanja B.; Filipovic Jelena Z.; Gržetić Ivan A.

    2013-01-01

    Serbian thermal power plants (TPPs) produce siliceous fly ash from lignite in the quantity of approximately 6 million tons per year. The potential market for the use of fly ash is operational, but for the time being, only used by cement producers. Fly ash radioactivity could be one of the major points of concern when larger use of fly ash is planned, particularly in the Serbian construction industry. Radioactivity measurements have been conducted regularly ...

  18. Strata movement controlling effect of waste and fly ash backfillings in fully mechanized coal mining with backfilling face

    Institute of Scientific and Technical Information of China (English)

    Zhang Jixiong; Zhang Qiang; Huang Yanli; Liu Jinwei; Zhou Nan; Zan Dongfeng

    2011-01-01

    A fully mechanized coal mining with backfilling (FMCMB) provides advantages of safety and efficiency for coal mining under buildings,railways,and water bodies.According to the field geological conditions,we analyzed the controlling effect of strata movement by the waste and fly ash backfilling in FMCMB face.Based on the key strata theory,we established the equivalent mining thickness model,and analyzed the action of the bulk factor of backfilling body to the equivalent mining thickness.In addition,we numerically simulated the controlling function of the strata movement by backfilling bodies with different strength.And the numerical simulation result show that the deformation of stratum and the subsidence of surface can be controlled by FMCMB.The result provides references to the effective execution of fully mechanized coal mining with solid waste backfilling in goal.

  19. Investigations into NOx emissions and burnout for coals with high ash content in a bench scale test facility

    Energy Technology Data Exchange (ETDEWEB)

    Greul, U.; Kluger, F.; Peter, G.; Spliethoff, H.; Hein, K.R.G. [University of Stuttgart, Stuttgart (Germany). Inst. fuer Verfahrenstechnik und Dampfkesselwesen

    2000-07-01

    At the Stuttgart University's Institute of Process Engineering and Power Plant Technology (IVD) investigations of in-furnace DeNOx technologies with regard to their NOx reduction efficiency are carried out using an electrically heated bench-scale test facility to evaluate the effect of different process parameters independently. The DeNOx technologies of air and fuel staging have been demonstrated to be effective control techniques to reduce NOx from stationary sources. For a wide range of brown and hard coals from Europe, South Africa and Australia test runs with air-staged combustion have been carried out. The ash content of the hard coals used was in the range between 8 and 28%. The investigated parameters were temperature (1000-1300{degree}C), stoichiometry (1.25-0.55), and residence time (1-6 s) in the fuel rich primary zone. With increasing temperatures and residence times in fuel-rich conditions in air-staged combustion NOx emissions below 300 mg/m{sup 3} can be achieved even with hard coals. For a few brown coals NOx values lower than 100 mg/m{sup 3} are possible. Dependent on the coal rank individual parameters are more important than others. For low and medium volatile hard coals the increasing of the residence time is more effective than higher temperature or lower air ratios in the primary zone. However, with high volatile hard coal or brown coal as primary fuel the influence of temperature and stoichiometry in the primary zone plays a key role for NOx reduction effectiveness. The burnout led to restrictions in large scale applications for air-staged combustion especially with hard coals as primary fuel. Investigations at different primary air ratios and temperatures show the effect of these parameters on the burnout values along the course of combustion. 7 refs., 14 figs., 2 tabs.

  20. Experiments on effects of coal particle ash content on ash formation during fluidized bed combustion%流化床燃烧中煤含灰量对灰渣形成特性的影响

    Institute of Scientific and Technical Information of China (English)

    王勤辉; 徐志; 刘彦鹏; 骆仲泱; 倪明江

    2012-01-01

    为了研究煤颗粒灰质量分数对煤在流化床燃烧过程中灰渣形成特性的影响,在一台小型流化床反应炉上进行煤的灰质量分数对灰渣形成特性的实验.按煤颗粒的灰质量分数,把义马烟煤分为6个颗粒组,并选用各颗粒组的3个粒径范围的煤颗粒进行燃烧实验,研究煤颗粒的灰质量分数对底渣质量分数、底渣与飞灰中的碳量质量分数和粒径分布的影响.结果表明,随着煤颗粒灰质量分数的增加,燃烧形成的底渣质量分数增加,而煤颗粒的燃尽率和飞灰中的碳质量分数都降低.在粒径和燃烧时间相同的条件下,随着颗粒灰质量分数的增加,底渣中留在本粒径档的颗粒质量分数明显增加,而细颗粒的质量分数明显减少.而颗粒灰质量分数对飞灰的粒径分布没有明显的影响.%To investigate the influences of coal particle ash content on the ash formation behaviors during fluidized bed combustion, experiments were conducted on a bench-scale fluidized bed combustor. Yima bituminous coal samples were divided into 6 ranks with different ash content. For every rank of coal sample, 3 size ranges were used in the experiments. The results show that the mass fraction of the bottom residue increases with the ash content of the coal particles, while the burnout of coal particles and the carbon content of the fly ash decrease with the ash content of coal particles. The mass fraction of the bottom residues which have the same size range as the initial size range of the coal particles increases with the ash content. While the ash content of coal particles has no obvious influence on the size distribution of the fly ash.

  1. Coal fly ash interaction with environmental fluids: Geochemical and strontium isotope results from combined column and batch leaching experiments

    Energy Technology Data Exchange (ETDEWEB)

    Brubaker, Tonya M; Stewart, Brian W; Capo, Rosemary C; Schroeder, Karl T; Chapman, Elizabeth C; Spivak-Birndorf, Lev J; Vesper, Dorothy J; Cardone, Carol R; Rohar, Paul C

    2013-05-01

    The major element and Sr isotope systematics and geochemistry of coal fly ash and its interactions with environmental waters were investigated using laboratory flow-through column leaching experiments (sodium carbonate, acetic acid, nitric acid) and sequential batch leaching experiments (water, acetic acid, hydrochloric acid). Column leaching of Class F fly ash samples shows rapid release of most major elements early in the leaching procedure, suggesting an association of these elements with soluble and surface bound phases. Delayed release of certain elements (e.g., Al, Fe, Si) signals gradual dissolution of more resistant silicate or glass phases as leaching continues. Strontium isotope results from both column and batch leaching experiments show a marked increase in {sup 87}Sr/{sup 86}Sr ratio with continued leaching, yielding a total range of values from 0.7107 to 0.7138. For comparison, the isotopic composition of fluid output from a fly ash impoundment in West Virginia falls in a narrow range around 0.7124. The experimental data suggest the presence of a more resistant, highly radiogenic silicate phase that survives the combustion process and is leached after the more soluble minerals are removed. Strontium isotopic homogenization of minerals in coal does not always occur during the combustion process, despite the high temperatures encountered in the boiler. Early-released Sr tends to be isotopically uniform; thus the Sr isotopic composition of fly ash could be distinguishable from other sources and is a useful tool for quantifying the possible contribution of fly ash leaching to the total dissolved load in natural surface and ground waters.

  2. Preparation of activated carbon with low ash content and high specific surface area from coal in the presence of KOH

    Institute of Scientific and Technical Information of China (English)

    XIE Qiang(解强); CHEN Qing-ru(陈清如); GONG Guo-zhuo(宫国卓); ZHANG Xiang-lan(张香兰); XU De-ping(许德平)

    2003-01-01

    An activated carbon with ash content less than 10% and specific surface area more than 1 600 m2/g was prepared from coal and the effect of K-containing compounds in preparation of coal-based activated carbon was investigated in detail in this paper. KOH was used in co-carbonization with coal, changes in graphitic crystallites in chars derived from carbonization of coal with and without KOH were analyzed by X-ray diffraction (XRD) technique, activation rates of chars with different contents of K-containing compounds were deduced, and resulting activated carbons were characterized by nitrogen adsorption isotherms at 77 K and iodine numbers. The results showed that the addition of KOH to the coal before carbonization can realize the intensive removal of inorganic matters from chars under mild conditions, especially the efficient removal of dispersive quartz, an extremely difficult separated mineral component in other processes else. Apart from this, KOH demonstrates a favorable effect in control over coal carbonization with the goal to form nongraphitizable isotropic carbon precursor, which is a necessary prerequisite for the formation and development of micro pores. However, the K-containing compounds such as K2CO3 and K2O remaining in chars after carbonization catalyze the reaction between carbon and steam in activation, which leads to the formation of macro pores. In the end an innovative method, in which KOH is added to coal before carbonization and K-containing compounds are removed by acid washing after carbonization, was proposed for the synthesis of quality coal-based activated carbon.

  3. Coal fly ash as raw material for the manufacture of geopolymer-based products.

    Science.gov (United States)

    Andini, S; Cioffi, R; Colangelo, F; Grieco, T; Montagnaro, F; Santoro, L

    2008-01-01

    In this work coal fly ash has been employed for the synthesis of geopolymers. Two different systems with silica/alumina ratios stoichiometric for the formation of polysialatesiloxo (PSS, SiO2/Al2O3=4) and polysialatedisiloxo (PSDS, SiO2/Al2O3=6) have been prepared. The alkali metal hydroxide (NaOH or KOH) necessary to start polycondensation has been added in the right amount as concentrated aqueous solution to each of the two systems. The concentration of each alkali metal solution has been adjusted in order to have the right liquid volume to ensure constant workability. The systems have been cured at four different temperatures (25, 40, 60, and 85 degrees C) for several different times depending on the temperature (16-672 h at 25 degrees C; 72-336 h at 40 degrees C; 16-120 h at 60 degrees C and 1-6h at 85 degrees C). The products obtained in the different experimental conditions have been submitted to the quantitative determination of the extent of polycondensation through mass increase and loss on ignition, as well as to qualitative characterization by means of FT-IR spectroscopy. Furthermore, physico-structural and mechanical characterization has been carried out through microscopic observations and the determination of unconfined compressive strength, elasticity modulus, apparent density, porosity and specific surface area. The results have indicated that the systems under investigation are suited for the manufacture of pre-formed building blocks at room temperature.

  4. Potential Use of Malaysian Thermal Power Plants Coal Bottom Ash in Construction

    Directory of Open Access Journals (Sweden)

    Abdulhameed Umar Abubakar

    2012-11-01

    Full Text Available As Malaysia focuses its attention to the call for a “greener” culture, so did the engineers and those in the scientific community especially the construction industry who is a major contributor to the depletion of green house gases. The engineering and construction community has now taken up the challenge for the use of “green and recycled by-products” in construction. One of those by-products is the Coal Bottom Ash (CBA from thermal power plants that faces an increasing production running into hundreds of thousand tonnes in Malaysia alone, and its method of disposal is relegated to landfills alone with no other commercial usage. The construction industry is now forced to rethink on the utilization of the industrial by-products as supplementary materials due to the continuous depletion of natural aggregates in construction. A significant amount of research has been conducted elsewhere on CBA to ascertain its pozzolanic activity, compressive strength in concrete and mortar, durability, water absorption characteristics and density, in order to ensure its usage as a construction material. In this paper, a critical review of the strength characteristics of concrete and mortar as influenced by CBA as partial replacement of fine aggregate is presented based on the available information in the published literatures. Diverse physical and chemical properties of CBA from different power plants in Malaysia are also presented. The influence of different types, amounts and sources of CBA on the strength and bulk density of concrete is discussed. The setting time, workability and consistency as well as the advantages and disadvantages of using CBA in construction materials are also highlighted. An effective utilization of CBA in construction materials will significantly reduce the accumulation of the by-products in landfills and thus reduce environmental pollution.

  5. Preparation of Active Absorbent for Flue Gas Desulfurization From Coal Bottom Ash: Effect of Absorbent Preparation Variables

    Directory of Open Access Journals (Sweden)

    Chang Chin Li, Lee Keat Teong, Subhash Bhatia and Abdul Rahman Mohamed

    2012-08-01

    Full Text Available An active absorbent for flue gas desulfurization was prepared from coal bottom ash, calcium oxide (CaO and calcium sulfate by hydro-thermal process. The absorbent was examined for its micro-structural properties. The experiments conducted were based on Design Of Experiments (DOE according to 23 factorial design. The effect of various absorbent preparation variables such as ratio of CaO to bottom ash (A, hydration temperature (B and hydration period (C towards the BET (Brunauer-Emmett-Teller specific surface area of the absorbent were studied. At a CaO to bottom ash ratio = 2, hydration temperature = 200 ?C and hydration period = 10 hrs, absorbent with a surface area of 90.1 m2/g was obtained. Based on the analysis of the factorial design, it was concluded that factor A and C as well as the interaction of factors ABC and BC are the significant factors that effect the BET surface area of the absorbent. A linear mathematical model that describes the relation between the independent variables and interaction between variables towards the BET specific surface area of the absorbent was also developed. Analysis of variance (ANOVA showed that the model was significant at 1% level.Key Words: Absorbent, Bottom Ash, Design Of Experiments, Desulfurization, Surface Area.

  6. Leaching of Major and Minor Elements during the Transport and Storage of Coal Ash Obtained in Power Plant

    Directory of Open Access Journals (Sweden)

    Rada Krgović

    2014-01-01

    Full Text Available In power plant, coal ash obtained by combustion is mixed with river water and transported to the dump. Sequential extraction was used in order to assess pollution caused by leaching of elements during ash transport through the pipeline and in the storage (cassettes. A total of 80 samples of filter ash as well as the ash from active (currently filled and passive (previously filled cassettes were studied. Samples were extracted with distilled water, ammonium acetate, ammonium oxalate/oxalic acid, acidic solution of hydrogen-peroxide, and a hydrochloric acid. Concentrations of the several elements (Al, As, Cd, Co, Cu, Cr, Fe, Ba, Ca, Mg, Ni, Pb, and Zn in all extracts were determined by inductively coupled plasma atomic emission spectrometry. Pattern recognition method was carried out in order to provide better understanding of the nature of distribution of elements according to their origins. Results indicate possible leaching of As, Ca, Cd, Cu, Zn, and Pb. Among these elements As, Cd, and Pb are toxicologically the most important but they were not present in the first two phases with the exception of As. The leaching could be destructive and cause negative effects on plants, water pollution, and damage to some life forms.

  7. Study on Type C Coal Fly ash as an Additive to Molding Sand for Steel Casting

    Science.gov (United States)

    Palaniappan, Jayanthi

    2016-05-01

    Study of physio-chemical properties studies such as granulometric analysis, moisture, X ray fluorescence etc. were performed with Type C coal—combustion fly ash to investigate their potential as a distinct option for molding sand in foundry, thereby reducing the dependency on latter. Technological properties study such as compressive strength, tensile strength, permeability and compaction of various compositions of fly ash molding sand (10, 20 and 30 % fly ash substitute to chemically bonded sand) were performed and compared with silica molding sand. Steel casting production using this fly ash molding sand was done and the casting surface finish and typical casting parameters were assessed. It was noted that a good quality steel casting could be produced using type C fly ash molding sand, which effectively replaced 20 % of traditional molding sand and binders thereby providing greater financial profits to the foundry and an effective way of fly ash utilization (waste management).

  8. Strontium isotopes as tracers of airborne fly ash from coal-fired power plants

    International Nuclear Information System (INIS)

    The paper presents the results of a controlled greenhouse experiment in which a native desert plant, the brittlebush was grown on admixtures of desert soils and fly ash. The fly ash is strongly enriched in Sr and the brittlebush is a Sr accumulator. The data demonstrate that the brittlebush isotopically equilibrates with desert soils whose fly ash components are as low as 0.25% by weight, the fly ash Sr is apparently more available to the plant than Sr derived from the soils, and the difference between the 87Sr/86Sr ratio of the fly ash (0.70807) and soils (0.71097 to 0.71117) warrants further investigations in the natural environment to determine the practicality of this method as a natural tracer of fly ash in the environment

  9. MCM-41 SYNTHESIZED FROM COAL FLY ASH AS A CATALYST IN THE PRODUCTION OF BIODIESEL USING PALM OIL.

    OpenAIRE

    M. R.; Deshpande; Kalyankar, N. V.; U.D. JOSHI

    2013-01-01

    Coal fly ash was used to synthesize MCM-41 by alkali fusion followed by hydro- thermal treatment and was characterized using various techniques viz. XRD, SEM, FTIR, BET method for surface area measurement etc. The synthesis conditions were optimized to obtain highly crystalline MCM-41 with utmost BETsurface area 1102m2/g with high purity. The crystalline nature of the prepared MCM-41 was found to change with fusion temperature and a maximum value was obtained at 5500 C. The cost of synthesize...

  10. Utilization of the Baker soil test in synthetic soil preparation for reclamation of coal ash disposal sites

    International Nuclear Information System (INIS)

    Application of procedures developed for preparation of synthetic soils for reclamation of two coal ash disposal sites in Pennsylvania is presented. These procedures include determination of water holding properties, lime requirement, and the Baker Soil Test (BST) for chemical element analysis. Results from soil and plant analyses following establishment of vegetation on the sites have shown that the BST predicts plant incorporation of chemical elements from the synthetic soils. The results confirm the utility of the BST in planning and executing successful reclamation on disturbed lands in a manner which protects the soil-plant-animal food chain

  11. JV Task 5 - Evaluation of Residual Oil Fly Ash As A Mercury Sorbent For Coal Combustion Flue Gas

    Energy Technology Data Exchange (ETDEWEB)

    Robert Patton

    2006-12-31

    The mercury adsorption capacity of a residual oil fly ash (ROFA) sample collected form Florida Power and Light Company's Port Everglades Power Plant was evaluated using a bituminous coal combustion flue gas simulator and fixed-bed testing protocol. A size-segregated (>38 {micro}g) fraction of ROFA was ground to a fine powder and brominated to potentially enhance mercury capture. The ROFA and brominated-ROFA were ineffective in capturing or oxidizing the Hg{sup 0} present in a simulated bituminous coal combustion flue gas. In contrast, a commercially available DARCO{reg_sign} FGD initially adsorbed Hg{sup 0} for about an hour and then catalyzed Hg{sup 0} oxidation to produce Hg{sup 2+}. Apparently, the unburned carbon in ROFA needs to be more rigorously activated in order for it to effectively capture and/or oxidize Hg{sup 0}.

  12. Chemical characterization of bottom ashes generated during combustion of a Colombian mineral coal in a thermal power plant

    International Nuclear Information System (INIS)

    Bottom ashes generated during combustion of a mineral coal from Colombia were characterized by X-ray fluorescence spectrometry and X-ray diffraction. The interest in this particular coal is due to the fact that it will be used by a thermal power plant in Ceara, Northeastern Brazil, where it could produce over 900 tons of different residues/combustion products every day. Results from Xray fluorescence allowed identification and quantification of elements present in the sample: silicon (59,17%), aluminum (13,17%), iron (10,74%), potassium (6,11%), titanium (2,91%), calcium (4,97%), sulphur (0,84%) and others (2,09%). The X-ray diffraction revealed patterns from silica, mullite, calcium sulphate and hydrated sodium. Results obtained so far indicate that the material is a potential raw-material for use in the formulation of ceramic components (author)

  13. Natural radioactivity of ground waters and soil in the vicinity of the ash repository of the coal-fired power plant. Nikola Tesla A in Obrenovac, Yugoslavia

    Energy Technology Data Exchange (ETDEWEB)

    Vukovic, Z.; Madic, M.; Vukovic, D. [Institute of Nuclear Sciences Vinca, Belgrade (Yugoslavia)

    1996-11-01

    Radioactivity of U, Th and {sup 40}K has been investigated in the vicinity of the ash repository of coal-fired Nikola Tesla A power plant in Obrenovac (Yugoslavia). Using alpha and gamma spectrometry, luminescence spectrophotometry, it was found that the ash repository is a source of radionuclides of the uranium and thorium series; and these radionuclides were found in the ground water up to a distance of several hundred metres. The influence of the repository on the soil radioactivity was minimal.

  14. Why is Coal Ash of Concern and How to Assess Potential Impacts

    Science.gov (United States)

    EPA's new test methods - the leaching environmental assessment framework (LEAF) are discussed including how they have been used to evaluate fly ash and scrubber residues. Work to evaluate high-volume encapsulated use of fly ash in cementitious material is also described.

  15. Comparison of lime and fly ash as amendments to acidic coal mine refusej growth responses and trace-element uptake of two grasses

    Energy Technology Data Exchange (ETDEWEB)

    Jasrow, J. D.; Zimmerman, C. A.; Dvorak, A. J.; Hinchman, R. R.

    1979-10-01

    Two commonly used revegetation species, Kentucky 31 tall fescue (Festuca arundinacea Schreb.) and Lincoln smooth brome (Bromus inermis Leyss.) were grown for 60 days in pots containing coarse coal mine refuse (referred to as gob, pH = 3.5) that was amended with lime or alkaline fly ash. Both species were also grown in pots containing a silt-loam surface soil as a control. Morphological growth parameters were measured over time; dry weights and shoot:root ratios were determined at harvest. Concentrations of Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, V, and Zn in the plant shoots were determined by atomic absorption spectrophotometry. Plant growth of both species was not as good on either lime- or fly ash-amended gob as it was on surface soil. Although plant height and length of the longest lead were not significantly different (p > 0.10) at the end of the experiment for plants grown on the two amended-gob substrates, parameters giving an indication of plant vigor (i.e., number of leaves and stems, width of the longest lead, and biomass) were significantly greater (p < 0.01) for plants grown on lime-amended gob than for those grown on fly ash-amended gob. Significant (p < 0.05) differences in the tissue concentrations of Cd, Co, Fe, Hg, Mn, Pb, V, and Zn were found among the plants grown on the three substrates. Except for Hg and Pb, these elements were higher in plants grown on at least one of the amended-gob substrates than in plants grown on surface soil. Significant substrate differences were not observed for Al, As, Cr, Cu, Ni, and Se. The tissue concentrations of some elements - notably Al, Cu, Fe, Mn, V, and Zn - were high enough in plants from one or more of the substrates to either approach or exceed concentrations that have been reported to be associated with toxic effects in some plant species.

  16. Comparison of CO2 capture by ex-situ accelerated carbonation and in in-situ naturally weathered coal fly ash.

    Science.gov (United States)

    Muriithi, Grace N; Petrik, Leslie F; Fatoba, Olanrewaju; Gitari, Wilson M; Doucet, Frédéric J; Nel, Jaco; Nyale, Sammy M; Chuks, Paul E

    2013-09-30

    Natural weathering at coal power plants ash dams occurs via processes such as carbonation, dissolution, co-precipitation and fluid transport mechanisms which are responsible for the long-term chemical, physical and geochemical changes in the ash. Very little information is available on the natural carbon capture potential of wet or dry ash dams. This study investigated the extent of carbon capture in a wet-dumped ash dam and the mineralogical changes promoting CO2 capture, comparing this natural phenomenon with accelerated ex-situ mineral carbonation of fresh fly ash (FA). Significant levels of trace elements of Sr, Ba and Zr were present in both fresh and weathered ash. However Nb, Y, Sr, Th and Ba were found to be enriched in weathered ash compared to fresh ash. Mineralogically, fresh ash is made up of quartz, mullite, hematite, magnetite and lime while weathered and carbonated ashes contained additional phases such as calcite and aragonite. Up to 6.5 wt % CO2 was captured by the fresh FA with a 60% conversion of calcium to CaCO3 via accelerated carbonation (carried out at 2 h, 4Mpa, 90 °C, bulk ash and a S/L ratio of 1). On the other hand 6.8 wt % CO2 was found to have been captured by natural carbonation over a period of 20 years of wet disposed ash. Thus natural carbonation in the ash dumps is significant and may be effective in capturing CO2.

  17. Study on the correlation between chemical and mineral composition of coal ashes; Sekitanbaibun no kobutsu soseigakuteki kento kagakubutsu sosei to kobutsugakuteki sosei no sokan

    Energy Technology Data Exchange (ETDEWEB)

    Hirato, M.; Nagashima, S.; Okada, S. [Hachinohe Institute of Technology, Aomori (Japan)

    1996-10-28

    Coal ash is a substance that has been mixed into minerals in the earth`s crust during their coalification process. Estimation was made on what kinds of mineral composition have been mixed into coals. Noted first was the kinds of compounds contained in the ash, wherein the ratios of mass in the compounds and minerals were correlated, and selection was made on minerals which are thought correlated. The selection criterion was based on minerals containing silica, alumina, iron oxide, lime and magnesium as compounds. Then, a phase equilibrium line diagram was used to estimate compositions and melting points of minerals which are thought to have been produced from these compounds. By comparing the estimation with the measured melting points of the ashes, mineral compositions thought reasonable were all selected. Assumption was possible on minerals that are thought to have been transferred into coal ash. Compound indications of ashes from 29 kinds of the world`s typical coals were replaced with the subject minerals and expressed as mineral compositions. As a method of calculation, stoichiometric coefficients for each mineral were determined by taking material balance in atomic/molecular levels in masses of compound aggregates and mineral composition aggregates. 7 tabs.

  18. Method for Determining the Hydration Reaction Kinetics of Coal Ashes%燃煤灰渣水化反应动力学测定方法研究

    Institute of Scientific and Technical Information of China (English)

    徐惠忠; 宋远明; 刘景相; 王波; 王志娟

    2011-01-01

    煤粉炉粉煤灰、沸腾炉渣和循环流化床固硫灰渣是3种具有代表性的燃煤灰渣.采用氢氧化钙变化量和化学结合水量表征方法,对燃煤灰渣的水化反应动力学进行研究.研究发现,由于燃煤灰渣中游离CaO的存在,用Ca(OH)2反应变化量研究其水化反应动力学时存在较大的干扰和误差;而用化学结合水量法则不受燃煤灰渣中游离CaO和SO3含量的影响,且与28 d抗压强度比方法所得结果相一致.结果表明,随着龄期增长,固硫灰渣或沸腾炉渣-水泥胶凝系统中,水化产物生成量明显高于粉煤灰-水泥胶凝系统;燃煤灰渣的火山灰活性与其CaO或SO3含量不存在必然联系.%Ashes from pulverized coal combustion(PCC) boiler, bubbling fluidized bed combustion(BFBC) boiler and circulating fluidized bed combustion(CFBC) boiler, namely, PC ashes, BFBC ashes and CFBC ashes respectively, are representative coal ashes. The hydration reaction kinetics of coal ashes was investigated by the change of Ca(OH)2 and chemically combined water content. It is found that there are some disturbances and errors for the study of the hydration reaction kinetics of coal ashes by means of the change of Ca(OH)2 content, while the method of chemically combined water content is independent of the content of free lime or SO3, in accordance with the results of 28 d compressive strength ratio. The results confirm that the content of the hydration products of BFBC ashes or CFBC ashes-cement pastes is greater than that of PC ashes-cement pastes, and the pozzolanic activity of coal ashes is not closely related to the content of CaO or SO3.

  19. 煤种及灰成分对燃煤固硫效果影响的研究进展%Effect of coal type and ash composition on fixed-sulfur technology of coal combustion

    Institute of Scientific and Technical Information of China (English)

    任艳娇; 杨巧文; 赵璐炜; 杨金华; 陈思; 赵昕伟; 李靖涛

    2014-01-01

    Coal is the main source of energy in China,the fixed-sulfur technology of coal combus-tion is an effective mean of controlling the SO2 emissions. With the production of coal ash increases year by year but the utilization ratio is low.Therefore,the research and utilization of coal ash is imperative. This paper summarized the effects of different coal types and ash composition on fixed-sulfur technology of coal combustion,and pointing out the trend of ash resource utilization.%煤炭是我国的主要能源,燃煤固硫技术是控制SO2排放的有效手段之一。随着燃煤灰渣的产量逐年增加,其利用率却较低,因此,对煤灰的研究利用刻不容缓。本文总结了不同煤种及煤灰成分对燃煤固硫效果的影响,指出灰渣资源化综合利用的发展趋势。

  20. Mineralogical and elemental composition of fly ash from pilot scale fluidised bed combustion of lignite, bituminous coal, wood chips and their blends

    Energy Technology Data Exchange (ETDEWEB)

    Nikolaos Koukouzas; Jouni Hamalainen; Dimitra Papanikolaou; Antti Tourunen; Timo Jantti [Institute for Solid Fuels Technology and Applications, Ptolemais (Greece). Centre for Research and Technology Hellas

    2007-09-15

    The chemical and mineralogical composition of fly ash samples collected from different parts of a laboratory and a pilot scale CFB facility has been investigated. The fabric filter and the second cyclone of the two facilities were chosen as sampling points. The fuels used were Greek lignite (from the Florina basin), Polish coal and wood chips. Characterization of the fly ash samples was conducted by means of X-ray fluorescence (XRF), inductive coupled plasma-optical emission spectrometry (ICP-OES), thermogravimetric analysis (TGA), particle size distribution (PSD) and X-ray diffraction (XRD). According to the chemical analyses the produced fly ashes are rich in CaO. Moreover, SiO{sub 2} is the dominant oxide in fly ash with Al{sub 2}O{sub 3} and Fe{sub 2}O{sub 3} found in considerable quantities. Results obtained by XRD showed that the major mineral phase of fly ash is quartz, while other mineral phases that are occurred are maghemite, hematite, periclase, rutile, gehlenite and anhydrite. The ICP-OES analysis showed rather low levels of trace elements, especially for As and Cr, in many of the ashes included in this study compared to coal ash from fluidised bed combustion in general. 23 refs., 3 figs., 5 tabs.

  1. Removal of sulfuric acid mist from lead-acid battery plants by coal fly ash-based sorbents.

    Science.gov (United States)

    Shu, Yuehong; Wei, Xiangyu; Fang, Yu; Lan, Bingyan; Chen, Hongyu

    2015-04-01

    Sorbents from coal fly ash (CFA) activated by NaOH, CaO and H2O were prepared for H2SO4 mist removal from lead-acid battery plants. The effects of parameters including temperature, time, the ratios of CFA/activator and water/solid during sorbent preparation were investigated. It is found that the synthesized sorbents exhibit much higher removal capacity for H2SO4 mist when compared with that of raw coal fly ash and CaO except for H2O activated sorbent and this sorbent was hence excluded from the study because of its low capacity. The H2SO4 mist removal efficiency increases with the increasing of preparation time length and temperature. In addition, the ratios of CFA/activator and water/solid also impact the removal efficiency, and the optimum preparation conditions are identified as: a water/solid ratio of 10:1 at 120 °C for 10h, a CFA:CaO weight ratio of 10:1, and a NaOH solution concentration of 3 mol/L. The formation of rough surface structure and an increased surface area after NaOH/CaO activation favor the sorption of H2SO4 mist and possible sorption mechanisms might be electrostatic attractions and chemical precipitation between the surface of sorbents and H2SO4 mist.

  2. Analytical model for erosion behaviour of impacted fly-ash particles on coal-fired boiler components

    Indian Academy of Sciences (India)

    S K Das; K M Godiwalla; S P Mehrotra; K K M Sastry; P K Dey

    2006-10-01

    Fly ash particles entrained in the flue gas from boiler furnaces in coal-fired power stations can cause serious erosive wear on steel surfaces along the flow path. Such erosion can significantly reduce the operational life of the boiler components. A mathematical model embodying the mechanisms of erosion on behaviour, has been developed to predict erosion rates of coal-fired boiler components at different temperatures. Various grades of steels used in fabrication of boiler components and published data pertaining to boiler fly ash have been used for the modelling. The model incorporates high temperature tensile properties of the target metal surface at room and elevated temperatures and has been implemented in an user-interactive in-house computer code (EROSIM–1), to predict the erosion rates of various grades of steel. Predictions have been found to be in good agreement with the published data. The model is calibrated with plant and experimental data generated from a high temperature air-jet erosion-testing facility. It is hoped that the calibrated model will be useful for erosion analysis of boiler components.

  3. Analytical model for erosion behaviour of impacted fly-ash particles on coal-fired boiler components

    Energy Technology Data Exchange (ETDEWEB)

    Das, S.K.; Godiwalla, K.M.; Mehrotra, S.P.; Sastry, K.K.M.; Dey, P.K.

    2006-10-15

    Fly ash particles entrained in the flue gas from boiler furnaces in coal-fired power stations can cause serious erosive wear on steel surfaces along the flow path. Such erosion can significantly reduce the operational life of the boiler components. A mathematical model, embodying the mechanisms of erosion on behaviour, has been developed to predict erosion rates of coal-fired boiler components at different temperatures. Various grades of steels used in fabrication of boiler components and published data pertaining to boiler fly ash have been used for the modelling. The model incorporates high temperature tensile properties of the target metal surface at room and elevated temperatures and has been implemented in an user-interactive in-house computer code (EROSIM-1), to predict the erosion rates of various grades of steel. Predictions have been found to be in good agreement with the published data. The model is calibrated with plant and experimental data generated from a high temperature air-jet erosion-testing facility. It is hoped that the calibrated model will be useful for erosion analysis of boiler components.

  4. A scanning electron microscopy study of ash, char, deposits and fuels from straw combustion and co-combustion of coal and straw

    Energy Technology Data Exchange (ETDEWEB)

    Sund Soerensen, H.

    1998-07-01

    The SEM-study of samples from straw combustion and co-combustion of straw and coal have yielded a reference selection of representative images that will be useful for future comparison. The sample material encompassed potential fuels (wheat straw and grain), bottom ash, fly ash and deposits from straw combustion as well as fuels (coal and wheat straw), chars, bottom ash, fly ash and deposits from straw + coal co-combustion. Additionally, a variety of laboratory ashes were studied. SEM and CCSEM analysis of the samples have given a broad view of the inorganic components of straw and of the distribution of elements between individual ash particles and deposits. The CCSEM technique does, however, not detect dispersed inorganic elements in biomass, so to get a more complete visualization of the distribution of inorganic elements additional analyses must be performed, for example progressive leaching. In contrast, the CCSEM technique is efficient in characterizing the distribution of elements in ash particles and between ash fractions and deposits. The data for bottom ashes and fly ashes have indicated that binding of potassium to silicates occurs to a significant extent. The silicates can either be in the form of alumino-silicates or quartz (in co-combustion) or be present as straw-derived amorphous silica (in straw combustion). This process is important for two reasons. One is that potasium lowers the melting point of silica in the fly ash, potentially leading to troublesome deposits by particle impaction and sticking to heat transfer surfaces. The other is that the reaction between potassium and silica in the bottom ash binds part of the potassium meaning that it is not available for reaction with chlorine or sulphur to form KCl or K{sub 2}SO{sub 4}. Both phases are potentially troublesome because they can condense of surfaces to form a sticky layer onto which fly ash particles can adhere and by inducing corrosion beneath the deposit. It appears that in the studied

  5. A critical comparison of spectrophotometric and potentiometric methods for the determination of fluoride and chloride in coal fly ash and clay

    Energy Technology Data Exchange (ETDEWEB)

    Andres-Garcia, E.; Blanco-Gonzales, E.; Diza-Garcia, M.E. [Faculty of Chemistry Avda. Julian Claveria, Oviedo (Spain)

    1995-12-31

    Coal and fly ash are currently monitored to control fluoride (and chloride) ground water and air pollution. In fact, fluorine emissions to the atmosphere provide the greatest potential individual source of environmental contamination by trace elements released from the utilization of coals. Chlorine, on the other hand, can contribute to the formation of a corrosive atmosphere during combustion and to the formation of acid precipitation, being thus an undesirable species in coal. Fly ash is a material which is produced in large quantities as a by-product of coal combustion in power plants (5-10 tons/h). This material can not be dumped without cheking that the ground water will not be polluted. During the last few years a group of laboratories has worked in several intercomparisons in the frame of the BCR-programm to improve their methods for fluorine and chlorine determination, especially for coal analyses. In this comunication we report on our experience in the certification of fluoride and chloride contents in coal, fly-ash and clay.

  6. Geochemical investigations of metals release from submerged coal fly ash using extended elutriate tests.

    Science.gov (United States)

    Bednar, A J; Chappell, M A; Seiter, J M; Stanley, J K; Averett, D E; Jones, W T; Pettway, B A; Kennedy, A J; Hendrix, S H; Steevens, J A

    2010-12-01

    A storage pond dike failure occurred at the Tennessee Valley Authority Kingston Fossil Plant that resulted in the release of over 3.8 million cubic meters (5 million cubic yards) of fly ash. Approximately half of this material deposited in the main channel of the Emory River, 3.5 km upstream of the confluence of the Emory and Clinch Rivers, Tennessee, USA. Remediation efforts to date have focused on targeted removal of material from the channel through hydraulic dredging, as well as mechanical excavation in some areas. The agitation of the submerged fly ash during hydraulic dredging introduces river water into the fly ash material, which could alter the redox state of metals present in the fly ash and thereby change their sorption and mobility properties. A series of extended elutriate tests were used to determine the concentration and speciation of metals released from fly ash. Results indicated that arsenic and selenium species released from the fly ash materials during elutriate preparation were redox stable over the course of 10d, with dissolved arsenic being present as arsenate, and dissolved selenium being present as selenite. Concentrations of certain metals, such as arsenic, selenium, vanadium, and barium, increased in the elutriate waters over the 10d study, whereas manganese concentrations decreased, likely due to oxidation and precipitation reactions. PMID:20943255

  7. Relationship between selenium body burdens and tissue concentrations in fish exposed to coal ash at the Tennessee Valley Authority Kingston spill site

    Energy Technology Data Exchange (ETDEWEB)

    Mathews, Teresa J [ORNL; Fortner, Allison M [ORNL; Jett, Robert T [ORNL; Peterson, Mark J [ORNL; Carriker, Neil [Tennessee Valley Authority (TVA); Morris, Jesse G [ORNL; Gable, Jennifer [Environmental Standards, Inc.

    2014-01-01

    In December 2008, 4.1 million m3 of coal ash were released into the Emory and Clinch Rivers by the Tennessee Valley Authority (TVA) Kingston Fossil Plant. Coal ash contains several contaminants, including the bioaccumulative metalloid selenium (Se). Because Se is predominantly accumulated in aquatic organisms through dietary, rather than aqueous exposure, tissue-based toxicity thresholds for Se are currently being considered. The proposed threshold concentrations range between 4-9 g/g Se (dry wt.) in whole body fish, with a proposed fillet threshold of 11.8 g/g. In the present study we examined the spatial and temporal trends in Se bioaccumulation and examined the relationship between the Se content in fillets and in whole bodies of fish collected around the Kingston spill site to determine whether Se bioaccumulation was a significant concern at the ash spill site. While Se concentrations in fish (whole bodies and fillets) were elevated at sampling locations affected by the Kingston ash spill relative to reference locations, concentrations do not appear to be above risk thresholds and have not been increasing over the five year period since the spill. Our results are not only relevant to guiding the human health and ecological risk assessments at the Kingston ash spill site, but because of current national discussions on appropriate guidelines for Se in fish as well for the disposal of coal combustion wastes, our results are also relevant to the general understanding of Se bioaccumulation in contaminated water bodies.

  8. Impact of Coal Fly Ash Addition on Combustion Aerosols (PM2.5) from Full-Scale Suspension-Firing of Pulverized Wood

    DEFF Research Database (Denmark)

    Damø, Anne Juul; Wu, Hao; Frandsen, Flemming;

    2014-01-01

    The formation of combustion aerosols was studied in an 800 MWth suspension-fired power plant boiler, during combustion of pulverized wood pellets with and without addition of coal fly ash as alkali capture additive. The aerosol particles were sampled and characterized by a low-pressure cascade im...

  9. Ash transformation in suspension fired boilers co-firing coal and straw

    DEFF Research Database (Denmark)

    Zheng, Yuanjing; Jensen, Peter Arendt; Jensen, Anker Degn

    Appendix C: Paper in Fuel 87 (2008) 3304-3312: A kinetic study of gaseous potassium capture by coal minerals in a high temperature fixed-bed reactor......Appendix C: Paper in Fuel 87 (2008) 3304-3312: A kinetic study of gaseous potassium capture by coal minerals in a high temperature fixed-bed reactor...

  10. ANALYSIS OF ASH FUSION IN SHELL PULVERIZED-COAL GASIFICATION PROCESS%Shell粉煤气化工艺煤灰熔融性探析

    Institute of Scientific and Technical Information of China (English)

    李亚东; 王洪进; 王可运

    2011-01-01

    The process of fly ash formation and its features in Shell pulverized-coal gasification are introduced,the ash fusion analyzed and the operation proposal for a stable running of gasifier put forward.The ash fusion is not only related to the ash composition,but also to the interaction among the components in the ash during the combustion process.The temperature of ash fusion is mainly depending on the mineral composition in the coal,the composition and ratio of its oxides and combustion atmosphere.%介绍Shell粉煤气化工艺中飞灰的形成过程及其特性,对煤灰的熔融性进行探析并提出稳定气化炉运行的操作建议。煤灰的熔融特性不仅与灰的成分有关,还与燃烧过程中灰中各成分之间的相互作用有关。灰熔融性温度主要取决于煤中的矿物组成、其氧化物的成分和配比及燃烧气氛等。

  11. Application of paste technology to mitigate the dust emissions from handling of fly and bottom ash at coal fired power plant : CGTEE in Candiota, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Silva Marques, M.E. [Golder Associates Peru, Lima (Peru); Lima, H. [Golder Associates Brazil, Sao Paulo (Brazil); Mandl, B.; Francoeur, R.; Palkovits, F. [Golder Paste Technology Ltd., Mississauga, ON (Canada); Blois, R. [Companhia de Geracao Termica de Energia Electrica, Porto Alegre (Brazil)

    2010-07-01

    This paper discussed a method developed to reduce dust emissions generated in a fly ash handling procedure used at a thermal power plant located in the south of Brazil. The fly ash is collected in dry form at several locations in the plant and pneumatically conveyed to storage silos, where it is moistened with water in a mixer, loaded into dump trucks and deposited in a disposal area near a surface coal mine. The new solution created low density fly ash slurry in localized mixing tanks within the power plant. The low density slurry is pumped to an ash conditioning plant where the slurry is then mixed with the bottom ash, dewatered, and densified. The densified slurry is then pumped to an adjacent coal mine disposal site in order to be used as backfill in mined areas. The proposed method will significantly reduce dust emissions both inside and outside the plant, and will substantially reduce truck traffic at the mine. The method will reduce the environmental impacts associated with fly ash dust emissions in the region. 8 figs.

  12. An investigation of the segretation of the ash content of coal from the first Berezovskiy sector. Issledovaniye segregatsii zol'nosti uglya pervogo Berezovskogo uchastka

    Energy Technology Data Exchange (ETDEWEB)

    Varshavskiy, A.M.

    1985-01-01

    The variability of the ash content in individual volumes of coal sequentially disposed in a formation in different directions of its strike are satisfactorily characterized by the segregation factor. The studies of segregation were performed in a developed mathematical model of a seam using a special program. It is established that segregation of the ash content of a seam is regular: the segregation factor along the thickness is a factor of one to two greater than along the dip and strike of the seam. To stabilize the ash content of coal used at state regional electric power plants (GRES), it is expedient to use extracting averaging excavators, either chain or cutter, in extracting operations in a pit.

  13. Mercury removal from coal combustion flue gas by modified fly ash.

    Science.gov (United States)

    Xu, Wenqing; Wang, Hairui; Zhu, Tingyu; Kuang, Junyan; Jing, Pengfei

    2013-02-01

    Fly ash is a potential alternative to activated carbon for mercury adsorption. The effects of physicochemical properties on the mercury adsorption performance of three fly ash samples were investigated. X-ray fluorescence spectroscopy, X-ray photoelectron spectroscopy, and other methods were used to characterize the samples. Results indicate that mercury adsorption on fly ash is primarily physisorption and chemisorption. High specific surface areas and small pore diameters are beneficial to efficient mercury removal. Incompletely burned carbon is also an important factor for the improvement of mercury removal efficiency, in particular. The C-M bond, which is formed by the reaction of C and Ti, Si and other elements, may improve mercury oxidation. The samples modified with CuBr2, CuCl2 and FeCl3 showed excellent performance for Hg removal, because the chlorine in metal chlorides acts as an oxidant that promotes the conversion of elemental mercury (Hg0) into its oxidized form (Hg2+). Cu2+ and Fe3+ can also promote Hg0 oxidation as catalysts. HCl and O2 promote the adsorption of Hg by modified fly ash, whereas SO2 inhibits the Hg adsorption because of competitive adsorption for active sites. Fly ash samples modified with CuBr2, CuCl2 and FeCl3 are therefore promising materials for controlling mercury emissions. PMID:23596961

  14. Mercury removal from coal combustion flue gas by modified fly ash

    Institute of Scientific and Technical Information of China (English)

    Wenqing Xu; Hairui Wang; Tingyu Zhu; Junyan Kuang; Pengfei Jing

    2013-01-01

    Fly ash is a potential alternative to activated carbon for mercury adsorption.The effects of physicochemical properties on the mercury adsorption performance of three fly ash samples were investigated.X-ray fluorescence spectroscopy,X-ray photoelectron spectroscopy,and other methods were used to characterize the samples.Results indicate that mercury adsorption on fly ash is primarily physisorption and chemisorption.High specific surface areas and small pore diameters are beneficial to efficient mercury removal.Incompletely burned carbon is also an important factor for the improvement of mercury removal efficiency,in particular.The C-M bond,which is formed by the reaction of C and Ti,Si and other elements,may improve mercury oxidation.The samples modified with CuBr2,CuCl2 and FeCl3 showed excellent performance for Hg removal,because the chlorine in metal chlorides acts as an oxidant that promotes the conversion of elemental mercury (Hg0) into its oxidized form (Hg2+).Cu2+ and Fe3+ can also promote Hg0 oxidation as catalysts.HCland O2 promote the adsorption of Hg by modified fly ash,whereas SO2 inhibits the Hg adsorption because of competitive adsorption for active sites.Fly ash samples modified with CuBr2,CuCl2 and FeCl3 are therefore promising materials for controlling mercury emissions.

  15. Solidification Coal Fly Ash on A Textile Factory as Allelochemi to Alternative Portland Cement Wall House Anti-Moss

    Directory of Open Access Journals (Sweden)

    Prabang Setyono

    2012-01-01

    Full Text Available This research for the application of coal waste as fly ash for mixture cement the stonewall anti moss which hypothesis upon which Allelochemi. Using the coal waste  represent one of program of environment conservation which is in the form of 3R ( Reuse, Recycle And Reduce, so this research can be made pilot project in development and substance invention of anti moss and make friends with the environment. The research target is identifying moss type in region Surakarta, knowing mixture concentration having technical eligibility of construction and TCLP test ( Toxicity Characteristic Leachate Procedure and justification of  LC50 and LD50. Research was carried out in laboratory by in phases following: casting of Mixture cement and fly ash: test of mechanic strength, test of resilience to moss growth, test of ability adhesive to wall paint, making solid Matrix. Continued by a test Depress to use the Technotest Modena Italy then Test the assimilated: Chemical Ekstraksi in step by step. Fraction 1 until Faction 5, TCLP (Toxicity Characteristic Leaching Procedure Standard, TCLP ( Toxicity Characteristic Leaching Procedure Progressive and TCLP (Toxycity Characteristic Leaching Procedure Modification. The Allelochemi form be observed by means of  Microscopic observation. The results revealed that moss type found in region of Surakarta:  Dicranella heteromalla, Funaria hygrometrica  ( Hedwig., Rhodobryum giganteum ( Schwaegr. Par., Pogonatum contortum ( Brid.. Mixture prosentase of  fly ash which still fulfill the technical standard of concrete building construction is 20 - 40 %. Value LC 50 to animal test the goldfish 8950 ppm and  the LD 50 value to animal test the mencit 30,35 mg / kg BB so that near no toxic. The resistance process  of  moss growing at coat cement also got concentration 20 - 40 % through allelochemi mechanism. Ever greater of  fly ash prosentase at growth media the moss hence assess the heavy metal accumulation of  Pb, Cr

  16. Adsorption of anionic dyes from aqueous solutions onto coal fly ash and zeolite synthesized from coal fly ash; Adsorcao de corantes anionicos de solucao aquoso em cinza leve de carvao e zeolita de cinza leve de carvao

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Terezinha Elizabeth Mendes de

    2010-07-01

    Coal fly ash, a waste generated in coal-fired electric power plant, was used to synthesize zeolite by hydrothermal treatment with NaOH solution. The fly ash (CL-2) and this synthesized zeolite (ZM-2) that was characterized as hydroxy-sodalite were used as adsorbents for anionic dyes indigo carmine (IC), and reactive orange 16 (RO16) from aqueous solutions. Effects of contact time, initial dye concentration, pH, adsorbent mass, and temperature were evaluated in the adsorption processes. The kinetics studies indicated that the adsorption followed the pseudo-second order kinetics and that surface adsorption and intraparticle diffusion were involved in the adsorption mechanism. The thermodynamics parameters demonstrated that the adsorption was spontaneous for all adsorption processes. The enthalpy data confirmed the endothermic nature for all adsorption processes except for IC/ZM-2 system which was exothermic. The entropy data showed an increased disorder at the solid/solution interface during the adsorption for all systems except for IC/ZM-2 whose negative entropy value indicated a decreased disorder at the interface. The adsorption isotherms were closely fitted to the Langmuir linear equation. The maximum adsorption capacities were 1.48 mg/g for the IC/CL-2 system; 1.13 mg/g for IC/ZM-2; 0.96 mg/g for RO16/CL-2, and 1.14 mg/g for RO16/ZM-2 at room temperature. The desorption study carried out with water, with acid aqueous solutions, and with an alkali aqueous solution showed to be inefficient both for recovering the dyes and regenerating the adsorbents. (author)

  17. Synthesis of monoclinic Celsian from coal fly ash by using a one-step solid-state reaction

    OpenAIRE

    Long Gonzalez, D.; López Cuevas, J.; Gutierrez Chavarria, C.A.; Pena, P.; Baudin, C.; Turrillas Maisterra, Javier Miguel

    2010-01-01

    Monoclinic (Celsian) and hexagonal (Hexacelsian) Ba1−xSrxAl2Si2O8 solid solutions, where x = 0, 0.25, 0.375, 0.5, 0.75 or 1, were synthesized by using Coal Fly Ash (CFA) as main raw material, employing a simple one-step solid-state reaction process involving thermal treatment for 5 h at 850–1300 °C. Fully monoclinic Celsian was obtained at 1200 °C/5 h, for SrO contents of 0.25 ≤ x ≤ 0.75. However, an optimum SrO level of 0.25 ≤ x ≤ 0.375 was recommended for the stabilization of Celsian. These...

  18. Instrumental photon activation analysis of coal fly ashes using the internal standard method coupled with the standard addition method

    International Nuclear Information System (INIS)

    Multielement determinations of coal fly ashes (NIST SRM-1633a and BCR CRM-38) have been carried out by instrumental photon activation analysis using 30 MeV bremsstrahlung and the internal standard method coupled with the standard addition method. In these determinations, some major and minor constituent elements in the samples were properly used as effective internal standards. As a result, it was demonstrated that concentrations of 18 elements were determined accurately and precisely. Furthermore, a similar multielement determination has also been examined using 20 MeV bremsstrahlung. In this case, it was proved that better results can be achieved, because all interfering reactions were eliminated completely. (author) 14 refs.; 5 tabs

  19. Ancillary operations in coal preparation instrumentation on-line low cost sulfur and ash analyzer

    Energy Technology Data Exchange (ETDEWEB)

    Malito, M.L.

    1991-07-01

    The purpose of this document is to define the testing to be performed on field collected coal slurry samples by ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectroscopy). A total of 20 samples (8 from an Upper Freeport coal and 12 from an Oklahoma coal) are to be analyzed in triplicate for the elements S, Si, Al, Fe, Ca, and Mg. For each of the two coal slurry types (Upper Freeport and Oklahoma), a container of slurry labeled calibration'' has been prepared. These calibration slurries may be used to get the system tuned'' (note that the volume of the field collected slurries is relatively small and cannot be used to tune'' the system). The calibration slurries were made from the slurry collected from the drain from the second sampling stage during the field testing.

  20. Synthesis of Zeolites Na-P1 from South African Coal Fly Ash: Effect of Impeller Design and Agitation

    Directory of Open Access Journals (Sweden)

    Leslie Petrik

    2013-05-01

    Full Text Available South African fly ash has been shown to be a useful feedstock for the synthesis of some zeolites. The present study focuses on the effect of impeller design and agitation rates on the synthesis of zeolite Na-P1 which are critical to the commercialization of this product. The effects of three impeller designs (4-flat blade, Anchor and Archimedes screw impellers and three agitation speeds (150, 200 and 300 rpm were investigated using a modified previously reported synthesis conditions; 48 hours of ageing at 47 °C and static hydrothermal treatment at 140 °C for 48 hours. The experimental results demonstrated that the phase purity of zeolite Na-P1 was strongly affected by the agitation rate and the type of impeller used during the ageing step of the synthesis process. Although zeolite Na-P1 was synthesized with a space time yield (STY of 15 ± 0.4 kg d−1m−3and a product yield of 0.98±0.05 g zeolites/g fly ash for each impeller at different agitation speeds, zeolite formation was assessed to be fairly unsuccessful in some cases due the occurrence of undissolved mullite and/or the formation of impurities such as hydroxysodalite with the zeolitic product. This study also showed that a high crystalline zeolite Na-P1 can be synthesized from South African coal fly ash using a 4-flat blade impeller at an agitation rate of 200 rpm during the ageing step at 47 °C for 48 hours followed by static hydrothermal treatment at 140 °C for 48 hours.

  1. 利用电厂粉煤灰制备蒸养标准砖%Preparation of Standard Brick with Coal Ash of Power Plant by Steam Curing Method

    Institute of Scientific and Technical Information of China (English)

    荣令坤; 张金山; 赵俊梅

    2011-01-01

    利用包头地区电厂粉煤灰、少量水泥、河砂,在碱性复合激发剂存在的情况下通过湿热养护工艺制成承重标准砖.试验采用单因索试验设计,得到粉煤灰掺量58.3%的粉煤灰砖,湿热养护28 d抗压强度18.7 MPa,抗折强度3.4 MPa.对影响砖体强度的几个主要因素进行了分析.%The load-bearing standard brick was prepared by coal ash from a power plant of Baotou by wet thermo-curing method under alkaline compound activator, with addition of small quantity of cement and river sand. Through the singlefactor experiments,the bricks with fly ash contents of up to 58.3% were obtained and its compressive strength of the brick reached 18.7 MPa,and bending strength 3.4 MPa at thermo-curing of 28 d. Then,some factors influencing the hardness of the brick were analyzed.

  2. Solidification/stabilization of electric arc furnace dust using coal fly ash. Analysis of the stabilization process.

    Science.gov (United States)

    Pereira, C F; Rodríguez-Piñero, M; Vale, J

    2001-03-30

    In this paper, the stabilization of electric arc furnace (EAF) dust containing hazardous metals such as Pb, Cd, Cr or Zn is described. The treatment involves a waste solidification/stabilization (S/S) process, using coal fly ash as the fundamental raw material and main binder. The article also contains a brief review of the most important recent publications related to the use of fly ash as S/S agents. The efficacy of the process has been evaluated mainly through leaching tests on the solidified products and compliance with some imposed leachate limits. The concentration of metals leaching from the S/S products was strongly leachate pH dependent; thus, the final pH of the leachate is the most important variable in reaching the limits and, therefore, in meeting the stabilization goals. In this study, the dependence relationship between the leachate pH and the concentrations of metals in the leachate are analyzed; in some cases, this allows us to estimate the speciation of contaminants in the S/S solids and to understand the mechanism responsible for reduced leachability of heavy metals from solidified wastes.

  3. Synthesis of zeolite-P from coal fly ash derivative and its utilisation in mine-water remediation

    Directory of Open Access Journals (Sweden)

    Leslie F. Petrik

    2010-05-01

    Full Text Available Solid residues resulting from the active treatment of acid mine drainage with coal fly ash were successfully converted to zeolite-P under mild hydrothermal treatment conditions. Scanning electron microscopy showed that the zeolite-P product was highly crystalline. The product had a high cation exchange capacity (178.7 meq / 100 g and surface area (69.1 m2/g and has potential application in waste-water treatment. A mineralogical analysis of the final product identified zeolite-P, as well as mullite and quartz phases, which indicated incomplete dissolution of the fly ash feedstock during the ageing step. Further optimisation of the synthesis conditions would be required to attain complete utilisation of the feedstock. The zeolite-P was tested for decontamination potential of circumneutral mine water. High removal efficiency was observed in the first treatment, but varied for different contaminants. The synthesised zeolite-P exhibited a high efficiency for the removal of heavy metal cations, such as aluminium, iron, manganese, zinc, copper and nickel, from contaminated mine water, even with repeated use. For potassium, calcium, strontium and barium, the removal was only efficient in the first treatment and decreased rapidly with subsequent treatments, indicating preferential adsorption of the other metals. A continuous release of sodium was observed during decontamination experiments, which decreased with subsequent treatments, confirming that sodium was the main exchangeable charge-balancing cation present in the zeolite-P product.

  4. Characterization of Nanoporous Ceramic Granules Made with Coal Fly Ash and Their Utilization in Phenol Removal from Water

    Directory of Open Access Journals (Sweden)

    Zhaoqian Jing

    2013-01-01

    Full Text Available Coal fly ash has been evaluated as low-cost material for pollutants adsorption. But powdered fly ash is difficult to be separated from the adsorbate and solution after saturation. When it is made into granules, this problem can be solved. Granules with uniform diameter of 6 mm were prepared and used as adsorbents for phenol removal from aqueous solution. The physical and chemical characteristics of the granules were investigated. The data indicated that the granules were abundant with nanosize pores of 9.8 nm on average. The specific surface area and porosity reached 130.5 m2/g and 60.1%, respectively. The main components in the granules were SiO2, Al2O3, MgO, Fe2O3, CaO, K2O, and unburned carbon. The adsorption batch experiments showed that this granular material was an efficient adsorbent for phenol removal. Phenol adsorption on the granules was mainly influenced by dosage and contact time. Increase in the dosage could enhance phenol adsorption effectively. More than 90% phenol could be removed under normal temperature and neutral pH with initial concentration of 100 mg/L, contact time of 90 min, and dosage of 140 g/L. The adsorption of phenol on the granules was spontaneous and complied well with the pseudo-second-order model and Langmuir isotherm model.

  5. Augmenting the Stability of OB Dump by Using Fly Ash: A Geo Technical Approach to Sustainably Manage OB Dump at Jharia Coal Field, India

    Directory of Open Access Journals (Sweden)

    Anup Kumar Gupta*

    2016-04-01

    Full Text Available This paper is mainly focused over the possible utilization of fly ash along with OB dump to enhance the stability of OB dump and thus provide a sustainable approach for better waste management of both these materials simultaneously. Instability of coal mine overburden (OB dumps is an important problem in most of the coal mines like Jharia coalfields in India. This is mainly occurring due to sliding nature of the rock material, lack of vegetation etc. Numbers of Environmental and health issues are associated with these unstable OB dumps. As it may easily flow with running water can contaminate the nearby water resource as well as carbonaceous content of the dump causes air pollution due to simultaneous combustion. On the other hand management of coal ash that is produced from thermal plants is also an important task. Dumping of fly ash in open may cause number of environmental problems. Various geotechnical and physical parameters such as particle size analysis, specific gravity, density, and friction angle/cohesion test have been performed to check the stability of OB dump and to analyze impacts of fly ash utilization to stabilize the OB dump.

  6. Mineralogy and geochemistry of a superhigh-organic-sulfur coal, Yanshan Coalfield, Yunnan, China: Evidence for a volcanic ash component and influence by submarine exhalation

    Science.gov (United States)

    Dai, S.; Ren, D.; Zhou, Y.; Chou, C.-L.; Wang, X.; Zhao, L.; Zhu, Xudong

    2008-01-01

    The mineralogy and geochemistry of a superhigh-organic-sulfur (SHOS) coal of Late Permian age from the Yanshan Coalfield, Yunnan Province, southwestern China, have been studied using optical microscope, low-temperature ashing plus X-ray diffraction analysis, scanning electron microscope equipped with energy-dispersive X-ray spectrometer, a sequential chemical extraction procedure, and inductively coupled plasma mass spectrometry. The M9 Coal from the Yanshan Coalfield is a SHOS coal that has a total sulfur content of 10.12%-11.30% and an organic sulfur content of 8.77%-10.30%. The minerals in the coal consist mainly of high-temperature quartz, sanidine, albite, muscovite, illite, pyrite, and trace amounts of kaolinite, plagioclase, akermanite, rutile, and dawsonite. As compared with ordinary worldwide (bituminous coals and anthracite) and Chinese coals, the M9 Coal is remarkably enriched in B (268????g/g), F (841????g/g), V (567????g/g), Cr (329????g/g), Ni (73.9????g/g), Mo (204????g/g), and U (153????g/g). In addition, elements including Se (25.2????g/g), Zr (262????g/g), Nb (20.1????g/g), Cd (2.07????g/g), and Tl (2.03????g/g) are also enriched in the coal. Occurrence of high-temperature quartz, sanidine, muscovite, and illite in the M9 Coal is evidence that there is a volcanic ash component in the coal that was derived from acid volcanic ashes fallen into the swamp during peat accumulation. Occurrence of albite and dawsonite in the coal and strong enrichment of some elements, including F, S, V, Cr, Ni, Mo and U, are attributed to the influence by submarine exhalation which invaded along with seawater into the anoxic peat swamp. Abundances of lithophile elements, including rare earth elements, Nb, Y, Zr, and TiO2, indicate that the silicate minerals in the coal were derived from the northern Vietnam Upland to the south of the basin. ?? 2008 Elsevier B.V. All rights reserved.

  7. Real-Time Cell-Electronic Sensing of Coal Fly Ash Particulate Matter for Toxicity-Based Air Quality Monitoring.

    Science.gov (United States)

    Moe, Birget; Yuan, Chungang; Li, Jinhua; Du, Haiying; Gabos, Stephan; Le, X Chris; Li, Xing-Fang

    2016-06-20

    The development of a unique bioassay for cytotoxicity analysis of coal fly ash (CFA) particulate matter (PM) and its potential application for air quality monitoring is described. Using human cell lines, A549 and SK-MES-1, as live probes on microelectrode-embedded 96-well sensors, impedance changes over time are measured as cells are treated with varying concentrations (1 μg/mL-20 mg/mL) of CFA samples. A dose-dependent impedance change is determined for each CFA sample, from which an IC50 histogram is obtained. The assay was successfully applied to examine CFA samples collected from three coal-fired power plants (CFPs) in China. The samples were separated into three size fractions: PM2.5 (10 μm). Dynamic cell-response profiles and temporal IC50 histograms of all samples show that CFA cytotoxicity depends on concentration, exposure time (0-60 h), and cell-type (SK-MES-1 > A549). The IC50 values differentiate the cytotoxicity of CFA samples based on size fraction (PM2.5 ≈ PM10-2.5 ≫ PM10) and the sampling location (CFP2 > CFP1 ≈ CFP3). Differential cytotoxicity measurements of particulates in human cell lines using cell-electronic sensing provide a useful tool for toxicity-based air quality monitoring and risk assessment. PMID:27124590

  8. Toxic airborne S, PAH, and trace element legacy of the superhigh-organic-sulphur Raša coal combustion: Cytotoxicity and genotoxicity assessment of soil and ash.

    Science.gov (United States)

    Medunić, Gordana; Ahel, Marijan; Mihalić, Iva Božičević; Srček, Višnja Gaurina; Kopjar, Nevenka; Fiket, Željka; Bituh, Tomislav; Mikac, Iva

    2016-10-01

    This paper presents the levels of sulphur, polycyclic aromatic hydrocarbons (PAHs), and potentially toxic trace elements in soils surrounding the Plomin coal-fired power plant (Croatia). It used domestic superhigh-organic-sulphur Raša coal from 1970 until 2000. Raša coal was characterised by exceptionally high values of S, up to 14%, making the downwind southwest (SW) area surrounding the power plant a significant hotspot. The analytical results show that the SW soil locations are severely polluted with S (up to 4%), and PAHs (up to 13,535ng/g), while moderately with Se (up to 6.8mg/kg), and Cd (up to 4.7mg/kg). The composition and distribution pattern of PAHs in the polluted soils indicate that their main source could be airborne unburnt coal particles. The atmospheric dispersion processes of SO2 and ash particles have influenced the composition and distribution patterns of sulphur and potentially toxic trace elements in studied soils, respectively. A possible adverse impact of analysed soil on the local karstic environment was evaluated by cytotoxic and genotoxic methods. The cytotoxicity effects of soil and ash water extracts on the channel catfish ovary (CCO) cell line were found to be statistically significant in the case of the most polluted soil and ash samples. However, the primary DNA-damaging potential of the most polluted soil samples on the CCO cells was found to be within acceptable boundaries. PMID:27232961

  9. 煤气冷却器积灰原因与解决措施%Causes for Ash Accumulation in Coal Gas Cooler and Measures of Solution

    Institute of Scientific and Technical Information of China (English)

    郭肖选; 张彦民

    2013-01-01

    对Shell粉煤气化装置中煤气冷却器的积灰问题进行了探讨,并介绍了解决积灰问题的措施.通过采用配煤技术、改造煤气冷却器过热段吹灰器、新增l台能力较大的激冷气压缩机等措施后,基本上解决了制约气化装置的积灰问题,实现了高负荷下的长周期运行.%An inquiry is made into the problem of ash accumulation in the coal gas cooler after the Shell pulverized coal gasifier,and measures are described for the solution of the problem of ash accumulation.The problem of ash accumulation that constrains the gasifier is basically solved by the use of coal blending,reform of the soot blower of the superheat section of the coal gas cooler,and new addition of one large capacity quench gas compressor,resulting in long-period operation under high load.

  10. Toxic airborne S, PAH, and trace element legacy of the superhigh-organic-sulphur Raša coal combustion: Cytotoxicity and genotoxicity assessment of soil and ash.

    Science.gov (United States)

    Medunić, Gordana; Ahel, Marijan; Mihalić, Iva Božičević; Srček, Višnja Gaurina; Kopjar, Nevenka; Fiket, Željka; Bituh, Tomislav; Mikac, Iva

    2016-10-01

    This paper presents the levels of sulphur, polycyclic aromatic hydrocarbons (PAHs), and potentially toxic trace elements in soils surrounding the Plomin coal-fired power plant (Croatia). It used domestic superhigh-organic-sulphur Raša coal from 1970 until 2000. Raša coal was characterised by exceptionally high values of S, up to 14%, making the downwind southwest (SW) area surrounding the power plant a significant hotspot. The analytical results show that the SW soil locations are severely polluted with S (up to 4%), and PAHs (up to 13,535ng/g), while moderately with Se (up to 6.8mg/kg), and Cd (up to 4.7mg/kg). The composition and distribution pattern of PAHs in the polluted soils indicate that their main source could be airborne unburnt coal particles. The atmospheric dispersion processes of SO2 and ash particles have influenced the composition and distribution patterns of sulphur and potentially toxic trace elements in studied soils, respectively. A possible adverse impact of analysed soil on the local karstic environment was evaluated by cytotoxic and genotoxic methods. The cytotoxicity effects of soil and ash water extracts on the channel catfish ovary (CCO) cell line were found to be statistically significant in the case of the most polluted soil and ash samples. However, the primary DNA-damaging potential of the most polluted soil samples on the CCO cells was found to be within acceptable boundaries.

  11. Investigations of the surface tension of coal ash slags under gasification conditions; Untersuchungen zur Oberflaechenspannung von Kohleschlacken unter Vergasungsbedingungen

    Energy Technology Data Exchange (ETDEWEB)

    Melchior, Tobias

    2011-10-26

    In the context of CO{sub 2}-emission-induced global warming, greenhouse gases resulting from the production of electricity in coal-fired power plants gain increasing attention. One possible way to reduce such emissions is to gasify coal instead of burning it. The corresponding process is referred to as Integrated Gasification Combined Cycle and allows for the separation of CO{sub 2} before converting a synthesis gas into electrical energy. However, further improvements in efficiency and availability of this plant technology are needed to render the alternative generation of electricity sensible from an economic point of view. One corresponding approach introduces hot gas cleaning facilities to the gasification plant which guarantee a removal of slag particles from the synthesis gas at high temperatures. The development of such filters depends on the availability of data on the material properties of the coal ash slags to be withdrawn. In this respect, the surface tension is a relevant characteristic. Currently, the surface tension of real coal ash slags as well as of synthetic model systems was measured successfully by means of the sessile drop and the maximum bubble pressure method. With regard to the sessile drop technique, those experiments were conducted in a gasification-like atmosphere at temperatures of up to 1500 C. Furthermore, the pressure inside the experimental vessel was raised to 10 bar in order to allow for deriving the influence of this variable on the surface tension. In contrast, maximum bubble pressure trials were realised at atmospheric pressure while the gas atmosphere assured inert conditions. For performing sessile drop measurements, a corresponding apparatus was set up and is described in detail in this thesis. Three computer algorithms were employed to calculate surface tensions out of the photos of sessile drops and their individual performance was evaluated. A very good agreement between two of the codes was found while the third one

  12. Magnetic susceptibility mapping of fly ash in soil samples near a coal-burning power plant in Pointe Coupee Parish, Louisiana.

    Science.gov (United States)

    Elhelou, O.; Richter, C.

    2015-12-01

    Atmospheric deposition of pollutants is a major health and environmental concern. In a 2010 study, the CATF attributed over 13,000 deaths each year to fly ash and other fine particles emitted by U.S. coal-burning power plants. The magnetic properties of fly ash allows for mapping an area suspect of PM pollution faster and more efficiently than by conducting chemical analysis as the former alternative. The objective of this study is to detect the presence of magnetic particles related to the migration of fly ash from a nearby coal power plant over parts of Pointe Coupee Parish, LA. This is based on the idea that the fly ash that is released into the atmosphere during the coal burning process contains heavy metals and magnetic particles in the form of ferrospheres, which can be used to trace back to the source. Maps of the top and sub soil were generated to differentiate the magnetic susceptibility values of the heavy metals potentially attributed to the migration and settling of fly ash onto the surface from any pre-existing or naturally occurring heavy metals in the sub soil. A 60 km2 area in Pointe Coupee Parish was investigated in approximately 0.5 km2 subsets. The area in Pointe Coupee Parish, LA was selected because land use is predominantly rural with the Big Cajun II power plant as the main contributor for air borne contaminants. Samples of fly ash obtained directly from the source below one of the power plant's precipitators were also analyzed to verify the field and laboratory analysis. Contour maps representing the spatial distribution of fly ash over Pointe Coupee, LA, along with histograms of magnetic susceptibility values, and chemical analysis all indicate a correlation between the proximity to the power plant and the predominant wind direction. Acquisition curves of the isothermal remnant magnetization demonstrate the presence of predominantly low coercivity minerals (magnetite) with a small amount of a high-coercivity phase. The microstructure of the

  13. Assessment of ecotoxicological risks of element leaching from pulvarized coal ashes.

    NARCIS (Netherlands)

    Jenner, H.A.

    1995-01-01

    This thesis describes the consequences of the disposal of the combustion residues of coal, especially the uptake of elements from such residues and their effects on various organisms. The effects on benthic organisms in fresh and in seawater are considered in the first two parts. The third part look

  14. Growth and metal uptake of the plant Cyperus esculentus and the worm Eisenia fetida in a worst-case experiment on coal fly-ash and Rhine sediment

    Energy Technology Data Exchange (ETDEWEB)

    Marquenie, J.M.; Crawley, D.K.; De Jong, P.; Jenner, H.A.

    1988-01-01

    The rapidly growing amount of non-reusable fly-ash form coal-fired power stations leads to growing concern about long-term environmental effects. This concern is focused on the total of elevated metal concentrations in fly-ash and not on the bioavailability. Attention is therefore particularly devoted to destruction and measurement techniques. The substrates used are a well known fly-ash, Rhine sediment as a 'contaminated' comparable sediment and a 'clean' sediment from a sand digging pit. The results indicate that the conclusion that fly-ash is a toxic waste product is not correct a priori. Earthworms did not show signs of added toxicity after thirty-two days in 100% fly-ash. The use of total metal concentrations for predicting the environmental hazard of fly-ash is not realistic if one takes into account the concentrations which are available for the biota, even if the results of such biotests that involve plants and/or worms are difficult to compare. 8 tabs., 32 refs.

  15. Growth and metal uptake of the plant Cyperus esculentus and the worm Eisenia fetida in a worst-case experiment on coal fly ash and Rhine sediment

    Energy Technology Data Exchange (ETDEWEB)

    Marquenie, J.M.; Crawley, D.K.; de Jong, P.; Jenner, H.A.

    1988-01-01

    The rapidly growing amount of non-reusable fly ash from coal-fired power stations leads to growing concern about long-term environmental effects. This concern is focused on the total of elevated-metal concentrations in fly ash and not on the bioavailability. Attention is therefore particularly devoted to destruction and measurement techniques. The substrates used are a well-known fly ash, Rhine sediment as a contaminated comparable sediment, and a clean sediment from a sand-digging pit. The results indicate that the conclusion that fly ash is a toxic-waste product is not correct a priori. Earthworms did not show signs of added toxicity after 32 days in 100% fly ash. The use of total-metal concentrations for predicting the environmental hazard of fly ash is not realistic if one takes into account the concentrations which are available for the biota, even if the results of such biotests that involve plants and/or worms are difficult to compare.

  16. The use of neutron activation analysis for the study of environmental risks associated with the fly ash from burning Polish coals

    International Nuclear Information System (INIS)

    The work oriented towards assessment of environmental risk associated with the emission of fly-ash into atmosphere and its storage on solid waste depositories included: 1. Elaboration of the INAA procedure for the determination of 20-24 elements in the fly-ashes. This method was next used for the analysis of fly-ashes from three different Polish power stations working on hard coal. 2. Studies on leaching of trace elements from neutron irradiated fly-ash by water and H2SO4 solution (pH=2.5) simulating acid rain. The results were compared with analogous experiments in which elements leached from non-irradiated fly-ash were determined by AAS and spectrophotometry. 3. Preparation and certification on the basis of an international intercomparison of the new Polish CRM - fine fly-ash (CTA-FFA-1). Although the certification is still not completed it is almost certain that it will be possible to establish ''recommended values'' for at least 34 elements and ''information values'' for another 10 to 16 ones. (author). 11 refs, 5 figs, 4 tabs

  17. Environmental impact of coal ash on tributary streams and nearshore waters of Lake Erie. Quarterly reports, August 31 and November 30, 1975, combined. [Cd, Zn, Cu, Fe, Mn, Cr, Ca, K, Mg, Na, Pb, As, Se

    Energy Technology Data Exchange (ETDEWEB)

    1975-01-01

    The study of coal wastes in Chautauga County, New York was begun on June 1, 1975. The major effort to date has been made on the fly ash dump west of Dunkirk, N.Y. The following topics are covered: description of the site; invertebrate biology; selection of trace elements for study and methods of analysis; water analyses; analyses of invertebrates; literature search; physical chemistry of coal ash and the leaching process; and study of lake sediments.

  18. Fine ash morphology and aerosol formation: A comparison of coal and biomass fuels

    Science.gov (United States)

    Chenevert, Blake Charles

    1998-12-01

    Modeling and experimental methods were used to investigate ash formation mechanisms of four industrially significant high-alkali biomass (sawdust/sanderdust) fuels. Alkali minerals tend to vaporize and recondense to form sub-micron aerosol, which poses health risks and causes special operational problems for industrial combustors. Sawdust/sanderdust was burned in a 15 kW natural gas-fired tunnel furnace. The resulting ash was collected by a water-cooled probe, and size sorted by cascade impaction and Electrical Aerosol Size Analysis. Scanning Electron Microscopy and Energy Dispersive X-Ray Spectroscopy techniques were used to determine morphology and composition by size cut. Three ash modes were present: (1) A residual mode composed primarily of porous calcium structures with a scale length of 8 microns and larger. This mode was likely the result of direct oxide and carbonate formation. (2) A secondary residual mode near 2 microns composed of fluxed and fragmented calcium, but also containing significant amounts of Si, Fe, Mn and Al. This mode appeared to be composed of eutectic melts separated from the parent ash particle. (3) An aerosol mode composed of Na and K with Cl anion, or sulfate anion when Cl was not present. The aerosol mode diameter was found to be a function of initial nucleate number density and coagulation time. Long coagulation time or high initial number density resulted in an aerosol mode diameter near 0.1 micron. Modeling was composed of three elements: (1) Equilibrium modeling---These calculations validated experimental evidence for alkali vaporization and condensation, predicting all alkali to enter the vapor phase as NaCl or KCl when Cl is available, or NaOH and KOH otherwise. (2) Condensation modeling---This model was used to determine the partitioning of alkali metal between homogeneous particulate matter formation (self-nucleation) and deposition on existing residual particles. It was shown that vaporized alkali can be collected on the

  19. Use of zeolitized coal fly ash in the simultaneous removal of ammonium and phosphate from aqueous solution

    Institute of Scientific and Technical Information of China (English)

    WU Deyi; HU Zhanbo; WANG Xinze; HE Shengbing; KONG Hainan

    2007-01-01

    Discharge of wastewater containing nitrogen and phosphate can cause cutrophication.Therefore,the development of an efficient material for the immobilization of the nutrients is important.In this study,a low calcium fly ash and high calcium fly ash were converted into zeolite using the hydrothermal method.The removal of ammonium and phosphate that coexist in aqueous solution by the synthesized zeolites were studied.The results showed that zeolitized fly ash could efficiently eliminate ammonium and phosphate at the same time.Saturation of zeolite with Ca2+ rather than Na+ favored the removal of both ammonium and Phosphate because the cation exchange reaction by the NH4+ resulted in the release of Ca2+ into the solution and precipitation of Ca2+ with POd43- followed.An increase in the temperature elevated the immobilization of phosphate whereas it abated the removal of ammonium.Nearly 60% removal efficiency for ammonium was achieved in the neutral pH range from 5.5 to 10.5.while the increase or decrease in pH out of the neutral range lowered the adsorption.In contrast,the removal of phosphate approached 100% at a pH lower than 5.0 or higher than 9.0,and less phosphate was immobilized at neutral pH.However,there was still a narrow pH range from 9.0 to 10.5 favoring the removal of both ammonium and phosphate.It was concluded that the removal of ammonium was caused by cation exchange;the contribution Of NH3 volatilization to immobilization at alkaline conditions(up to pH level of 11.4)was limited.with respect to phosphate immobilization,the mechanism was mainly the formation of precipitate as Ca3(PO4)2 within the basic pH range or as FePO4 and AlPO4 within acidic pH range.

  20. Synthesis and characterization of zeolite material from coal ashes modified by surfactant; Sintese e caracterizacao de material zeolitico de cinzas de carvao modificado por surfactante

    Energy Technology Data Exchange (ETDEWEB)

    Fungaro, D.A., E-mail: dfungaro@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (CQMA/IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Quimica e Meio Ambiente; Borrely, S.I. [Instituto de Pesquisas Energeticas e Nucleares (CTR/IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Tecnologia das Radiacoes

    2010-07-01

    Coal ash was used as starting material for zeolite synthesis by means of hydrothermal treatment. The surfactant-modified zeolite (SMZ) was prepared by adsorbing the cationic surfactant hexadecyltrimethylammonium bromide (HDTMA-Br) on the external surface of the zeolite from coal ash. The zeolite structure stability was monitored during the characterization of the materials by FTIR, XDR and SEM. The structural parameters of surfactant-modified zeolite are very close to that of corresponding non-modified zeolite which indicates that the crystalline nature of the zeolite remained intact after required chemical treatment with HDTMA-Br molecules and heating treatment for drying. The most intense peaks in the FTIR spectrum of HDTMA-Br were observed in SMZ spectrum confirming adsorption of surfactant on zeolites. (author)

  1. 论路用混凝土掺合料——粉煤灰%Road Mixes the Material with the Concretes Pulverized Coal Ash

    Institute of Scientific and Technical Information of China (English)

    李吉平

    2009-01-01

    This paper introduced the road mixes the material pulverized coal ash with the concretes the characteristic, technical performance, to pulverized coal ash quality requirement, standard, choice, design requirements and isometric substitution law and excess substitution method com-putation principle.%文章介绍了路用混凝土掺合料粉煤灰的特点、技术性能、对粉煤灰的质量要求、标准、选择,以及设计要求和配制混凝土时取代水泥的等量取代法和超量取代法的计算原理.

  2. Development of bricks with incorporation of coal ash and sludge from water treatment plant; Desenvolvimento de tijolos com incorporacao de cinzas de carvao e lodo provenientes de estacao de tratamento de agua

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Mauro Valerio da

    2011-07-01

    Sludge from treatment water Brazilian plant station are, frequently, disposed and launched directly in the water bodies, causing a negative impact in the environment. Also, coal ashes is produced by burning of coal in coal-fired power stations and is the industrial solid waste most generated in southern Brazil: approximately 4 million tons/y. The efficient disposal of coal ashes is an issue due to its massive volume and harmful risks to the environment. The aim of this work was study the feasibility of incorporating these two industrial wastes in a mass used in the manufacture of ecological bricks. Samples of fly ashes from a cyclone filter from a coal-fired power plant located at Figueira County in Parana State, Brazil and waterworks sludge of Terra Preta County in Sao Paulo State, Brazil, were used in the study. Fly ash-sludge and fly ash-sludge-soil-cement bricks were molded and tested, according to the Brazilians Standards. The materials were characterized by physical-chemical analysis, X-ray diffraction, thermal analysis, morphological analysis, Fourier transform infrared spectroscopy and granulometric analysis. The results indicate that the waterworks sludge and coal ashes have potential to be used on manufacturing soil-cement pressed bricks according to the of Brazilians Standards NBR 10836/94. (author)

  3. A new model to estimate CO2 coal gasification kinetics based only on parent coal characterization properties

    International Nuclear Information System (INIS)

    Highlights: • A mathematical model to predict gasification rate and residence time was proposed. • Gasification rate is affected mainly by micropore surface area and alkaline content. • Residence time for coal gasification can be predicted without a kinetic model. • Surface area based on carbon content is an important parameter in kinetic analysis. • The model can predict the kinetic of coal blends in any ash composition range. - Abstract: A new mathematical model is proposed for the estimation of CO2 gasification kinetics of different rank coals and ash contents. There are no previous reports on the determination of the conversion rate or even residence time of CO2 or steam gasification based on coal characterization and for a wide range of ash content. This new approach can be used to infer the residence time and other parameters required for reactor design and operation optimization of newly mined coals or coal mixtures used as feedstock. The coal micropore surface area and the alkaline content determined by the ash composition were proved to be the most significant variables influencing the gasification rate. These variables were correlated to formulate a semi-empirical expression based on the Arrhenius equation. An equation to infer residence time, independent of the kinetic model, is also presented. The new equation is important in understanding the catalytic effect of the alkaline content in the temperature range where the chemical reaction is the controlling step. It can also be used as the corresponding term of the chemical reaction in a gas–solid kinetic model when working at higher temperatures. This new approach is valid, if there is not loss of alkali and alkaline earth metals due to sublimation or melting, which results in a glassy slag structure. The proposed model has direct industrial application in simulation of gasifiers’ performance with the knowledge of only coal characterization properties

  4. Natural rain - induced element leaching from coal ASH; La pluie naturelle - lixiviation d'element de la cendre de charbon

    Energy Technology Data Exchange (ETDEWEB)

    Popovic, A.; Djordjevic, D.; Polic, P. [Belgrade Univ., Dept. of Chemistry, IChTM, Chemistry Center, Belgrade (Yugoslavia)

    2000-07-01

    Six composite samples of coal ash from power plants 'Nikola Tesla' A and B, located in the vicinity of Obrenovac, near Belgrade (Yugoslavia), were subjected to extraction with 1 M acetate solution, pH 5.5, in order to imitate possible leaching of the ash by natural acidic rain. Seven trace and five major elements have been examined, and the obtained amounts were in the range from 0.003 {+-} 0.001 ppm (Cd), to 117 {+-} 27 ppm (Ca), dry ash basis. Though some of the concentrations were higher than allowed by domestic and international regulations it can be concluded that neither of the examined elements represents a serious threat for the environment (at least for the conditions applied in this experiment). Also, both magnesium and iron are carriers of copper, chromium and arsenic, while cadmium is associated with magnesium and manganese. Calcium and manganese are beside magnesium and iron, scavengers of arsenic. (authors)

  5. A comparison between alkaline and decomplexing reagents to extract humic acids from low rank coals

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, D.; Cegarra, J.; Abad, M. [CSIC, Madrid (Spain). Centro de Edafologia y Biologia Aplicada del Segura

    1996-07-01

    Humic acids (HAs) were obtained from two low rank coals (lignite and leonardite) by using either alkali extractants (0.1 M NaOH, 0.1 M KOH or 0.25 M KOH) or solutions containing Na{sub 4}P{sub 2}O{sub 7} (0.1 M Na{sub 4}P{sub 2}O{sub 7} or 0.1 M NaOH/Na{sub 4}P{sub 2}O{sub 7}). In both coals, the greatest yields were obtained with 0.25 M KOH and the lowest with the 0.1 M alkalis, whereas the extractions based on Na{sub 4}P{sub 2}O{sub 7} yielded intermediate values and were more effective on the lignite. Chemical analysis showed that the leonardite HAs consisted of molecules that were less oxidized and had fewer functional groups than the HAs released form the lignite. Moreover, the HAs extracted by reagents containing Na{sub 4}P{sub 2}O{sub 7} exhibited more functional groups than those extracted with alkali, this effect being more apparent in lignite because of its greater cation exchange capacity. Gel permeation chromatography indicated that the leonardite HAs contained a greater proportion of higher molecular size compounds than the lignite HAs, and that both solutions containing Na{sub 4}P{sub 2}O{sub 7} released HAs with a greater proportion of smaller molecular compounds from the lignite than did the alkali extractants. 16 refs., 3 figs., 2 tabs.

  6. Best management practices plan for the Chestnut Ridge-Filled Coal Ash Pond at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-05-01

    The Chestnut Ridge Filled Coal Ash Pond (FCAP) Project has been established to satisfy Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) requirements for the Chestnut Ridge Operable Unit 2. FCAP is on Chestnut Ridge, approximately 0.5 miles south of the Y-12 Plant. A 62-foot high earthen dam across Upper McCoy Branch was constructed in 1955 to create a pond to serve as a settling basin for fly and bottom ashes generated by burning coal at the Y-12 Steam Plant. Ash from the steam was mixed with water to form a slurry and then pumped to the crest of Chestnut Ridge and released through a large pipe to flow across the Sluice Channel area and into the pond. The ash slurry eventually overtopped the dam and flowed along Upper McCoy Branch to Rogers Quarry. The purpose of this document is to provide a site-specific Best Management Practices (BMP) Plan for construction associated with environmental restoration activities at the FCAP Site.

  7. Study on solidification and stabilization technique by steam treatment of the coal ash from fluidized-bed combustion boilers; Ryudoso sekitanbai no joki shori ni yoru koka / anteika gijutsu ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Shibata, Y. [Kawasaki Heavy Industries Ltd., Kobe (Japan)

    1998-08-20

    In fluidized-bed coal combustion boiler supporting one end of boilers for power generation and process heating, coal ash comprised of the products of ash of coal and lime stone used for desulfurizer was used for raw material. The fluidized-bed combustion boiler really working at present is of normal pressure (AFBC) type due to bubbling or cycling system, and pressure type of the bubbling system (PFBC) due to high pressure of about 1.0 MPa is promoted development for a next generation type power generation. Then, by using the coal ash obtained from the AFBC boiler with different kind of coal, volume of boiler, and so on (AFBC ash) and the coal ash obtained from the PFBC boiler under actual proof operation, a study on properties of coal, lime stone and solids after steam treatment of mixture with water (kind/volume, strength and elution of hazard heavy metals of hydrates) were conducted to investigate to use for civil engineering materials such as road materials, filling back materials, and so forth. 16 refs., 13 figs., 2 tabs.

  8. Zeolite A synthesis employing a brazilian coal ash as the silicon and aluminum source and its applications in adsorption and pigment formulation

    Directory of Open Access Journals (Sweden)

    Lindiane Bieseki

    2012-01-01

    Full Text Available Zeolite A was synthesized using the coal ash from Siderópolis/RS - Brazil. The synthesis was based on a standard IZA synthesis using coal ash as the Si and Al source. XRF analysis showed that the coal ash has a Si/Al ratio of 1.52, which is close to the Si/Al ratio required to produce zeolite A (1.0. The synthesized materials were analyzed by XRD, SEM and N2 adsorption. More crystalline materials were obtained during synthesis when an additional treatment was applied at a temperature of 353 K at the dissolution of NaOH step. The product formed after 4 hours was the most crystalline, but even the product formed after 1 hour proved to be better than that formed using the standard 4 hours IZA synthesis. The zeolites synthesized by this method had an adsorption capacity of 120 mg.g-1 for Ca2+, half the capacity of commercial zeolite A (300 mg.g-1. It was not possible to obtain blue or green pigments using the synthesized zeolite A.

  9. Zeolite A synthesis employing a brazilian coal ash as the silicon and aluminum source and its applications in adsorption and pigment formulation

    Directory of Open Access Journals (Sweden)

    Lindiane Bieseki

    2013-02-01

    Full Text Available Zeolite A was synthesized using the coal ash from Siderópolis/RS - Brazil. The synthesis was based on a standard IZA synthesis using coal ash as the Si and Al source. XRF analysis showed that the coal ash has a Si/Al ratio of 1.52, which is close to the Si/Al ratio required to produce zeolite A (1.0. The synthesized materials were analyzed by XRD, SEM and N2 adsorption. More crystalline materials were obtained during synthesis when an additional treatment was applied at a temperature of 353 K at the dissolution of NaOH step. The product formed after 4 hours was the most crystalline, but even the product formed after 1 hour proved to be better than that formed using the standard 4 hours IZA synthesis. The zeolites synthesized by this method had an adsorption capacity of 120 mg.g-1 for Ca2+, half the capacity of commercial zeolite A (300 mg.g-1. It was not possible to obtain blue or green pigments using the synthesized zeolite A.

  10. PURIFICATION AND ENRICHMENT OF BIOGAS IN ASH-WATER MIXTURE

    Directory of Open Access Journals (Sweden)

    Andrzej Brudniak

    2014-10-01

    Full Text Available Biogas, produced in an aerobic digestion process, is a mixture of gases, and that is why its inexpensive and effective valorisation is essential. Research on this process is necessary in order to use biogas as a renewable energy source. The aim of this thesis is to present methods of biogas purification and enrichment in the fly ash - water mixture, that is generated on the base of fly ash produced during burning coal in power industry. Experience presented that the fly ash absorbs CO2 and H2S, even in conventional conditions. The absorption efficiency depends not only on the chemical composition of the ash but also on its physical properties. There was also a strong neutralization of alkaline waste combustion.

  11. Study on using thermo-mechanical analysis to determinate the coal ash fusibility%利用热机械分析仪测定煤灰熔融性的研究

    Institute of Scientific and Technical Information of China (English)

    孔令学; 白进; 李怀柱; 郭振兴; 白宗庆; 李文

    2015-01-01

    Combining with international coal ash fusibility determination method, the fusibility of coal ash was studied using thermo - mechanical analysis ( TMA ). The results showed that: international coal ash fusibility determination method cannot describe the coal ash fusibility under high temperature quantitatively, but TMA can not only obtain the fusibility of coal ash and the dynamic change of coal ash fusibility under high temperature during the whole heating process, but also at the same time, obtain the fusion rate of ash under high temperature, so the fusibility of coal ash could be determined quantitatively using TMA, the design and operation of wet bottom boiler and gasifier could be guided.%结合国标灰熔融性测定方法,利用热机械分析仪(TMA)对煤灰进行灰熔融性的测试研究。研究结果表明:国标灰熔融性测定方法得到的煤灰熔融特征温度无法定量描述煤灰在高温下的熔融行为,而 TMA 不仅能够获得煤灰的熔融性以及煤灰在整个加热过程中的熔融动态变化,同时可获得煤灰在高温下熔融的速率,因而可利用 TMA 定量测定灰熔融性,以指导液态排渣锅炉和气化炉的设计和操作。

  12. Impairment of soil health due to fly ash-fugitive dust deposition from coal-fired thermal power plants.

    Science.gov (United States)

    Raja, R; Nayak, A K; Shukla, A K; Rao, K S; Gautam, Priyanka; Lal, B; Tripathi, R; Shahid, M; Panda, B B; Kumar, A; Bhattacharyya, P; Bardhan, G; Gupta, S; Patra, D K

    2015-11-01

    Thermal power stations apart from being source of energy supply are causing soil pollution leading to its degradation in fertility and contamination. Fine particle and trace element emissions from energy production in coal-fired thermal power plants are associated with significant adverse effects on human, animal, and soil health. Contamination of soil with cadmium, nickel, copper, lead, arsenic, chromium, and zinc can be a primary route of human exposure to these potentially toxic elements. The environmental evaluation of surrounding soil of thermal power plants in Odisha may serve a model study to get the insight into hazards they are causing. The study investigates the impact of fly ash-fugitive dust (FAFD) deposition from coal-fired thermal power plant emissions on soil properties including trace element concentration, pH, and soil enzymatic activities. Higher FAFD deposition was found in the close proximity of power plants, which led to high pH and greater accumulation of heavy metals. Among the three power plants, in the vicinity of NALCO, higher concentrations of soil organic carbon and nitrogen was observed whereas, higher phosphorus content was recorded in the proximity of NTPC. Multivariate statistical analysis of different variables and their association indicated that FAFD deposition and soil properties were influenced by the source of emissions and distance from source of emission. Pollution in soil profiles and high risk areas were detected and visualized using surface maps based on Kriging interpolation. The concentrations of chromium and arsenic were higher in the soil where FAFD deposition was more. Observance of relatively high concentration of heavy metals like cadmium, lead, nickel, and arsenic and a low concentration of enzymatic activity in proximity to the emission source indicated a possible link with anthropogenic emissions. PMID:26450689

  13. Pyrite thermochemistry, ash agglomeration, and char fragmentation during pulverized coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Akan-Etuk, A.; Diaz, R.; Niksa, S.

    1991-10-01

    The objective of the present work is to introduce an experimental program that will eventually lead to time-resolved iron ash composition over the technological operating domain. The preceding literature survey suggests two important stipulations on any such experimental program. The first stipulation is that good control must be established over the operating conditions, to accurately quantify their effects. The other is that data must be obtained rapidly, to thoroughly cover the important operating domain. This work presents a series of studies that has characterized the desulfurization of pyrite during the early stages of combustion. An experimental system was established and used to monitor the effects of oxygen, temperature, and residence time on the evolution of condensed phase products of the combustion of pure pyrite. (VC)

  14. Pyrite thermochemistry, ash agglomeration, and char fragmentation during pulverized coal combustion. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Akan-Etuk, A.; Diaz, R.; Niksa, S.

    1991-10-01

    The objective of the present work is to introduce an experimental program that will eventually lead to time-resolved iron ash composition over the technological operating domain. The preceding literature survey suggests two important stipulations on any such experimental program. The first stipulation is that good control must be established over the operating conditions, to accurately quantify their effects. The other is that data must be obtained rapidly, to thoroughly cover the important operating domain. This work presents a series of studies that has characterized the desulfurization of pyrite during the early stages of combustion. An experimental system was established and used to monitor the effects of oxygen, temperature, and residence time on the evolution of condensed phase products of the combustion of pure pyrite. (VC)

  15. Hydraulic activity of belite cement from class C coal fly ash. Effect of curing and admixtures

    Directory of Open Access Journals (Sweden)

    Guerrero, A.

    2006-09-01

    Full Text Available The effect of curing method and a water-reducing additive on the hydraulic activity of high lime content (ASTM type C fly ash belite cement (FABC-2-W is reported. A class C fly ash was subjected to hydrothermal treatment and subsequent calcination to synthesize FABC. Hydraulic activity was evaluated in the cement paste over 180 days from the physically bound water content as determined by thermogravimetric analysis and the degree of hydration, in turn found with X-ray diffraction (XRD analysis. Mechanical strength, porosity and pore size distribution were also studied in equivalent mortar samples.En este trabajo se discute la influencia del tipo de curado y de un aditivo reductor de la demanda de agua en la actividad hidráulica de un cemento belítico de cenizas volantes de alto contenido en cal denominado (CBCV-2-A. Este cemento ha sido sintetizado por una ruta húmeda hidrotermal con posterior calcinación, empleando ceniza volante de alto contenido en cal (ASTM tipo C como materia prima. La actividad hidráulica se ha estudiado en la pasta de cemento, durante un periodo de 180 días, por medio del contenido de agua combinada, determinada por análisis termogravimétrico, y el grado de hidratación por difracción de rayos X (DRX. La resistencia mecánica y la porosidad total y distribución de tamaño de poro se han estudiado en probetas equivalentes de mortero

  16. Radionuclide Levels in Coal Ash and Cinder from Major Coal Users in Fujian Province%福建省主要燃煤企业煤灰(渣)中的天然放射性核素水平

    Institute of Scientific and Technical Information of China (English)

    温莉琴

    2011-01-01

    采用低本底NaI(Tl)γ谱仪对福建省13家主要燃煤企业共13个粉煤灰样品和10个煤渣样品中天然放射性核素水平进行了调查测量;依据国家标准《建筑材料放射性核素限量》的要求,对其用作建材原料的可行性进行了分析,结果表明,当建材原料100%为粉煤灰或煤渣时,约有31%的样品超过标准限值。%Natural radionuclide concentrations were investigated by using low-background NaI(Tl) gamma spectrometer for 13 pulverized coal ash samples and 10 coal cinder samples from 13 coal users in Fujian Province.Consistent with national standards Limits of Radionulcides in Construction Materials,analysis was made for these samples as construction materials.The results showed that radioactivity contents of 31% samples exceed the limits given if construction raw materials are all comprised of pulverized coal ash and coal cinder.

  17. The use of neutron activation analysis for the study of environmental risks associated with the fly ash from burning Polish coals

    International Nuclear Information System (INIS)

    An INAA procedure for the determination of twelve elements in fly ash and in similar geological materials was developed using mixed elemental standards and iron wire as neutron flux monitors. The reliability of the method was checked using the IAEA's Soil-5 and Lake Sediment SL-1 CRMs. The results obtained for the fly ash from burning Polish hard coal, as well as for two other geological materials, are presented. A new candidate reference material: fine fly ash (CTA-FFA-1) was collected, characterized with respect to its major component contents, homogenized, and distributed into PE containers. In order to certify the material with respect to its trace element contents, an international intercomparison run was organized. Preliminary experiments on leaching of trace elements from neutron-irradiated fly ash were performed. Some distinct differences in the leaching characteristics of individual elements were noted. In future the work will concentrate on extending the multielement capability of the INAA method, as well as on leaching of trace elements by solutions simulating acid rain. The work on certification of the new CRM, fine fly ash, CTA-FFA-1, will be continued. 28 refs, 9 figs, 4 tabs

  18. Leaching Behavior of Selected Trace and Toxic Metals in Coal Fly Ash Samples Collected from Two Thermal Power Plants, India.

    Science.gov (United States)

    Sandeep, P; Sahu, S K; Kothai, P; Pandit, G G

    2016-09-01

    Studies on leaching behavior of metals associated with coal fly ash (FA) are of great concern because of possible contamination of the aquatic environment. In the present study, leaching behavior of metals (As, Se, Cr, Pb, V, Zn, etc.) in two different FA samples (FA1 and FA2) was investigated at various pH (2-12), temperatures of leachate solution and using TCLP. At pH 2, the highest leaching was observed for Fe (21.6 and 32.8 µg/g), whereas at pH 12, Arsenic was found to have the highest leaching (1.5 and 2.4 µg/g) in FA1 and FA2. Leachate solution temperature showed a positive effect on the metal's leachability. In TCLP, most of the metal's leachability was observed to be higher than that of batch leaching tests. The present study suggests that, leaching of As and Se from FA samples can moderately affect ground/surface water quality at the study locations. PMID:27372455

  19. Influence of mechanical activation on the synthesis of Sr-Celsian employing a precursor mixture containing coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Badillo, C. M.; Lopez-Cuevas, J.; Rodriguez-Galicia, J. L.; Gutierrez-Chavarria, C. A.; Pech-Canul, M. I.

    2013-05-01

    Strontium aluminosilicate, SrAl{sub 2}Si{sub 2}O{sub 8} (SAS), was synthesized by a solid state reaction using coal fly ash (CFA) as main raw material. A precursor mixture of SrCO{sub 3}, CFA and Al{sub 2}O{sub 3} was mechanically-activated for times of up to 12 h using an attrition mill, and subsequently sintered at temperatures of 900-1300 degree centigrade. The CFA and the mechanical activation were employed with the aim to promote the transformation from the hexagonal (Sr-Hexacelsian) into the monoclinic (Sr-Celsian) polymorphic form of SAS, since the latter phase is associated with better physical and mechanical properties but the former tends to be the first one to appear. The mean particle size, the crystallite size and the temperature at the end of the curve of weight loss (Tf) decreased, while the specific surface area and the degree of amorphization increased, with increasing milling time. Samples milled for at least 4 h and then sintered at 1100 degree centigrade achieved full transformation into Sr-Celsian. The same result was obtained for sintering temperatures higher than 1100 degree centigrade, independently of milling time. An increment in both the milling time and the sintering temperature allowed us to improve the densification and the mechanical properties of the synthesized materials. (Author) 24 refs.

  20. Influence of mechanical activation on the synthesis of Sr-Celsian employing a precursor mixture containing coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Badillo, C. M.; Lopez-Cuevas, J.; Rodriguez-Galicia, J. L.; Gutierrez-Chavarria, C. A.; Pech-Canul, M. I.

    2013-06-01

    Strontium aluminosilicate, SrAl{sub 2}Si{sub 2}O{sub 8} (SAS), was synthesized by a solid state reaction using coal fly ash (CFA) as main raw material. A precursor mixture of SrCO{sub 3}, CFA and Al{sub 2}O{sub 3} was mechanically-activated for times of up to 12 h using an attrition mill, and subsequently sintered at temperatures of 900-1300 degree centigrade. The CFA and the mechanical activation were employed with the aim to promote the transformation from the hexagonal (Sr-Hexacelsian) into the monoclinic (Sr-Celsian) polymorphic form of SAS, since the latter phase is associated with better physical and mechanical properties but the former tends to be the first one to appear. The mean particle size, the crystallite size and the temperature at the end of the curve of weight loss (Tf) decreased, while the specific surface area and the degree of amorphization increased, with increasing milling time. Samples milled for at least 4 h and then sintered at 1100 degree centigrade achieved full transformation into Sr-Celsian. The same result was obtained for sintering temperatures higher than 1100 degree centigrade, independently of milling time. An increment in both the milling time and the sintering temperature allowed us to improve the densification and the mechanical properties of the synthesized materials. (Author)

  1. Mechanical Properties of High Strength Concrete Containing Coal Bottom Ash and Oil-Palm Boiler Clinker as Fine Aggregates

    Directory of Open Access Journals (Sweden)

    Soofinajafi Mahmood

    2016-01-01

    Full Text Available This research aims to utilize Coal Furnace Bottom ash (CBA and Oil-Palm Boiler Clinker (OPBC as fine aggregate in concrete mix proportions. They are solid wastes from power plant and Oil Palm industry, respectively. Since these by-products do not have any primary use and are pure waste, an opportunity to use them as aggregate in concrete industry not only is economical but also will be an environmental friendly opportunity leading towards a more sustainable production chain. CBA and OPBC sands had similar grading to normal sand but have lower density and higher water absorption. In a high strength concrete, normal sand was replaced up to 25% with either CBA or OPBC. Test results showed that although water absorption of these wastes was more than normal sand but the slump value of concrete containing each of these wastes showed that these concretes had good workability. All mixes containing these wastes had slightly lower compressive strength at early ages and equivalent or higher compressive strength at later ages compared to control mix. The 28-day compressive strength of these concretes was in the range of 69–76 MPa which can be categorized as high strength concrete. In general, the performance of OPBC was better than CBA at 25% replacement level. However, it is recommended that at least 12.5% of total volume of fine aggregate in a high strength concrete is used of CBA or OPBC.

  2. Compression properties of dust cake of fine fly ashes from a fluidized bed coal combustor on a ceramic filter

    Energy Technology Data Exchange (ETDEWEB)

    Choi, J.H.; Ha, S.J.; Jang, H.J. [Gyeongsang National University, Jinju (Republic of Korea). Dept. of Chemical Engineering & ERI

    2004-02-16

    Dust cake compressibility of fine fly ashes (from a coal power plant of fluidized bed combustor) on a ceramic filter was carefully investigated under well-controlled conditions and by measuring the cake thickness under filtration conditions using a laser displacement measuring system. Overall cake porosity and pressure drop of dust cake of three different particles of geometric mean diameters: 1.2, 2.2, and 3.6 {mu}m and the adjusted dynamic shape factors: 1.15, 1.28 and 1.64, respectively, were investigated, at face velocities of 0.02-0.08 m/s. Overall cake porosity was strongly dependent on face velocity and mass load but less dependent on particle sizes. It was understood that dust cake was compressed by reduction of previously formed cake layers with drag forces of lately formed dust layers. The expressions for overall cake porosity and pressure drop across the dust cake, and considering the compression effect, were developed with good agreement with experimental results.

  3. Acute pulmonary and systemic effects of inhaled coal fly ash in rats: Comparison to ambient environmental particles

    Energy Technology Data Exchange (ETDEWEB)

    Smith, K.R.; Veranth, J.M.; Kodavanti, U.P.; Aust, A.E.; Pinkerton, K.E. [University of California-Davis, Davis, CA (United States). Center of Health & Environmental

    2006-10-15

    The effect of coal fly ash (CFA) on pulmonary and systemic inflammation and injury was measured in male Sprague-Dawley rats exposed to filtered air or CFA for 4 h/day for 3 days. The average concentration of CFA particulate matter less than 2.5 {mu}m (PM2.5) was 1400 {mu} g/m{sup 3}, of which 600 {mu} g/m{sup 3} was PM1. Animals were examined 18 and 36 h postexposure. Chemical analysis of CFA detected silicon, calcium, aluminum, and iron as major components. Total number of neutrophils in bronchoalveolar lavage fluid (BALF) following exposure to CFA was significantly increased along with significantly elevated blood neutrophils. Exposure to CFA caused slight increases in macrophage inflammatory protein-2, and marked increases in transferrin in BALF. Interleukin-1 beta and total antioxidant potential in lung tissues were also increased in rats exposed to CFA. Histological examination of lung tissue demonstrated focal alveolar septal thickening and increased cellularity in select alveoli immediately beyond terminal bronchioles. These responses are consistent with the ability of CFA to induce mild neutrophilic inflammation in the lung and blood following short-term exposure at levels that could be occupationally relevant. However, when comparing the effects of CFA with those of concentrated ambient particles, CFA does not appear to have greater potency to cause pulmonary alterations.

  4. Catalytic spectrophotometric determination of trace vanadium in fly ash and coal gangue by Triton X-100 enhancing effect

    Institute of Scientific and Technical Information of China (English)

    XIA Changbin; HUANG Niandong

    2004-01-01

    Trace V(V) catalyzes mightily the decolorization reaction of arsenazo Ⅲ (AsA Ⅲ) by oxidizing with H2O2 in a pH 4.0 HAc-NaAc buffer solution, and the addition of Triton X-100 can further increase the sensitivity of the reaction and its catalytic extent is linear with the content of V(V). A catalytic spectrophotometric procedure for determining trace V(V)was developed. The results show that the maximun absorption of the color solution is at 560 nm and the detection limit of the method for V(V) is 0.014 mg@L-1 Beer's law is obeyed for V(V) in the range of 0.00-0.20 mg.L-1. The recoveries are 99.0%-104.6%, and the relative standard deviations (RSD) are 2.7%-3.7%. Combined with ion-exchange resin, the method has been applied to the determination of trace vanadium in fly ash and coal gangue with satisfactory results.

  5. Coal Ash Behavior in Reducing Environments (CABRE) III Year 6 - Activity 1.10 - Development of a National Center for Hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Stanislowski, Joshua; Azenkeng, Alexander; McCollor, Donald; Galbreath, Kevin; Jensen, Robert; Lahr, Brent

    2012-03-31

    The Energy & Environmental Research Center (EERC) has been conducting research on gasification for six decades. One of the objectives of this gasification research has been to maximize carbon conversion and the water–gas shift process for optimal hydrogen production and syngas quality. This research focus and experience were a perfect fit for the National Center for Hydrogen Technology ® (NCHT®) Program at the EERC for improving all aspects of coal gasification, which ultimately aids in the production and purification of hydrogen. A consortia project was developed under the NCHT Program to develop an improved predictive model for ash formation and deposition under the project entitled “Coal Ash Behavior in Reducing Environments (CABRE) III: Development of the CABRE III Model.” The computer-based program is now applicable to the modeling of coal and ash behavior in both entrained-flow and fluidized-bed gasification systems to aid in overall gasification efficiency. This model represents a significant improvement over the CABRE II model and runs on a Microsoft Windows PC platform. The major achievements of the CABRE III model are partitioning of inorganic transformations between various phases for specific gas cleanup equipment; slag property predictions, including standard temperature–viscosity curves and slag flow and thickness; deposition rates in gasification cleanup equipment; provision for composition analysis for all input and output streams across all process equipment, including major elements and trace elements of interest; composition analysis of deposit streams for various deposit zones, including direct condensation on equipment surfaces (Zone A), homogeneous particulate deposition (Zone B), and entrained fly ash deposition (Zone C); and physical removal of ash in cyclones based on D50 cut points. Another new feature of the CABRE III model is a user-friendly interface and detailed reports that are easily exportable into Word documents, Excel

  6. Effect of oxydesulphurization on the combustion characteristics of coal

    Energy Technology Data Exchange (ETDEWEB)

    Yaman, S.; Kucukbayrak, S. [Technical University of Istanbul, Istanbul (Turkey). Dept. of Chemical Engineering

    1997-06-01

    Desulphurization of a Turkish lignite by oxydesulphurization using dilute alkaline solutions, obtained by the extraction of fly ash with water, was carried out under 0-1.5 MPa partial pressure of oxygen at temperatures between 403 and 498 K for 30-90 min time intervals. The combustion characteristics of original and desulphurized lignite samples are compared using TGA. DTG curves were derived and the effects of desulphurization conditions such as temperature, partial pressure of oxygen and time on coal reactivity were studied. Ignition temperature, maximum combustion rate, combustion period, and the end temperature of combustion were considered. Relations between coal reactivity and removals of sulphur and ash contents were also studied.

  7. Recent history of sediment metal contamination in Lake Macquarie, Australia, and an assessment of ash handling procedure effectiveness in mitigating metal contamination from coal-fired power stations

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Larissa, E-mail: Larissa.Schneider@canberra.edu.au [Institute for Applied Ecology, University of Canberra, Canberra, ACT 2601 (Australia); Maher, William [Institute for Applied Ecology, University of Canberra, Canberra, ACT 2601 (Australia); Potts, Jaimie [New South Wales Office of Environmental and Heritage, Lidcombe, NSW, 2141 Australia (Australia); Gruber, Bernd [Institute for Applied Ecology, University of Canberra, Canberra, ACT 2601 (Australia); Batley, Graeme [CSIRO Land and Water, Lucas Heights, NSW 2234 (Australia); Taylor, Anne [Institute for Applied Ecology, University of Canberra, Canberra, ACT 2601 (Australia); Chariton, Anthony [CSIRO Land and Water, Lucas Heights, NSW 2234 (Australia); Krikowa, Frank [Institute for Applied Ecology, University of Canberra, Canberra, ACT 2601 (Australia); Zawadzki, Atun; Heijnis, Henk [Institute for Environmental Research, Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW 2234 (Australia)

    2014-08-15

    This study assessed historical changes in metal concentrations in sediments of southern Lake Macquarie resulting from the activities of coal-fired power stations, using a multi-proxy approach which combines {sup 210}Pb, {sup 137}Cs and metal concentrations in sediment cores. Metal concentrations in the lake were on average, Zn: 67 mg/kg, Cu: 15 mg/kg, As: 8 mg/kg, Se: 2 mg/kg, Cd: 1.5 mg/kg, Pb: 8 mg/kg with a maximum of Zn: 280 mg/kg, Cu: 80 mg/kg, As: 21 mg/kg, Se: 5 mg/kg, Cd: 4 mg/kg, Pb: 48 mg/kg. The ratios of measured concentrations in sediment cores to their sediment guidelines were Cd 1.8, As 1.0, Cu 0.5, Pb 0.2 and Zn 0.2, with the highest concern being for cadmium. Of special interest was assessment of the effects of changes in ash handling procedures by the Vales Point power station on the metal concentrations in the sediments. Comparing sediment layers before and after ash handling procedures were implemented, zinc concentrations have decreased 10%, arsenic 37%, selenium 20%, cadmium 38% and lead 14%. An analysis of contaminant depth profiles showed that, after implementation of new ash handling procedures in 1995, selenium and cadmium, the main contaminants in Australian black coal had decreased significantly in this estuary. - Highlights: • The main sources of metals to Southern Lake Macquarie are coal-fired power stations. • The metal of highest concern in this estuary is cadmium. • Arsenic was mobile in sediments. • Selenium and cadmium decreased in sediments following new ash handling procedures.

  8. Recent history of sediment metal contamination in Lake Macquarie, Australia, and an assessment of ash handling procedure effectiveness in mitigating metal contamination from coal-fired power stations

    International Nuclear Information System (INIS)

    This study assessed historical changes in metal concentrations in sediments of southern Lake Macquarie resulting from the activities of coal-fired power stations, using a multi-proxy approach which combines 210Pb, 137Cs and metal concentrations in sediment cores. Metal concentrations in the lake were on average, Zn: 67 mg/kg, Cu: 15 mg/kg, As: 8 mg/kg, Se: 2 mg/kg, Cd: 1.5 mg/kg, Pb: 8 mg/kg with a maximum of Zn: 280 mg/kg, Cu: 80 mg/kg, As: 21 mg/kg, Se: 5 mg/kg, Cd: 4 mg/kg, Pb: 48 mg/kg. The ratios of measured concentrations in sediment cores to their sediment guidelines were Cd 1.8, As 1.0, Cu 0.5, Pb 0.2 and Zn 0.2, with the highest concern being for cadmium. Of special interest was assessment of the effects of changes in ash handling procedures by the Vales Point power station on the metal concentrations in the sediments. Comparing sediment layers before and after ash handling procedures were implemented, zinc concentrations have decreased 10%, arsenic 37%, selenium 20%, cadmium 38% and lead 14%. An analysis of contaminant depth profiles showed that, after implementation of new ash handling procedures in 1995, selenium and cadmium, the main contaminants in Australian black coal had decreased significantly in this estuary. - Highlights: • The main sources of metals to Southern Lake Macquarie are coal-fired power stations. • The metal of highest concern in this estuary is cadmium. • Arsenic was mobile in sediments. • Selenium and cadmium decreased in sediments following new ash handling procedures

  9. Jatropha curcas: A potential crop for phytoremediation of coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Jamil, S.; Abhilash, P.C.; Singh, N.; Sharma, P.N. [National Botany Research Institute, Lucknow (India)

    2009-12-15

    A greenhouse pot experiment was conducted to test the heavy metal phytoremediation capacity of Jatropha curcas from fly ash. Both natural accumulation by J. curcas and chemically enhanced phytoextraction was investigated. Plants were grown on FA and FA amended with fertile garden soil, in presence and absence of chemical chelating agent EDTA at 0.1 g kg{sup -1} and 0.3 g kg{sup -1} of soil. EDTA enhanced the uptake of all five elements (Fe, Al, Cr, Cu and Mn) tested. Fe and Mn were retained more in roots while Cu, Al and Cr were translocated more to the shoot. Metal accumulation index indicates that the effect of EDTA at 0.3 g kg{sup -1} was more pronounced than EDTA at 0.1 g kg{sup -1} in terms of metal accumulation. Biomass was enhanced up to 37% when FA was amended with GS. Heavy metal uptake was enhanced by 117% in root, 62% in stem, 86% in leaves when EDTA was applied at 0.3 g kg{sup -1} to FA amended with GS. Study suggest that J. curcas has potential of establishing itself on FA when provided with basic plant nutrients and can also accumulate heavy metals many folds from FA without attenuating plant growth.

  10. PILOT DEMONSTRATION OF TECHNOLOGY FOR THE PRODUCTION OF HIGH VALUE MATERIALS FROM THE ULTRA-FINE (PM 2.5) FRACTION OF COAL COMBUSTION ASH

    Energy Technology Data Exchange (ETDEWEB)

    T.L. Robl; K.R. Henke; J.G. Groppo

    2004-09-01

    Broad range dispersants, including naphthalene sulfonate-formaldehyde condensates (NSF) and polycarboxylate based products, were tested on both wet and dry fly ash samples from the LG&E Energy Corp. plants in the study. Tests included both total adsorption and measurement of sedimentation rate via time density relationships. A wide range of dosages were required, ranging from 0.3 to 10 g/kg. In general the ponded ash required less dispersant. Leaching tests of 5% ash solutions by weight revealed a wide range of soluble salts to be present in the ash, and found a relationship between calcium ion concentration and dispersant dosage requirement. Other parameters measured included SO{sub 4}, Cl, F, NO{sub 3}, PO{sub 4}, Al, Ca, Mg, K, Na and alkalinity. An assessment was made of the available software to digitally model the overall process circuit. No prefabricated digital model was found for hydraulic classification or froth flotation. Work focused on building a model for hydraulic classification in an Excel spread sheet based on Stokes Law. A pilot plant scale hydraulic classifier was fabricated and operated. The performance of the hydraulic classifier was found to be forecastable within reasonable bounds, and work to improve both are ongoing.

  11. Effect of alkalinity on nitrite accumulation in treatment of coal chemical industry wastewater using moving bed biofilm reactor.

    Science.gov (United States)

    Hou, Baolin; Han, Hongjun; Jia, Shengyong; Zhuang, Haifeng; Zhao, Qian; Xu, Peng

    2014-05-01

    Nitrogen removal via nitrite (the nitrite pathway) is more suitable for carbon-limited industrial wastewater. Partial nitrification to nitrite is the primary step to achieve nitrogen removal via nitrite. The effect of alkalinity on nitrite accumulation in a continuous process was investigated by progressively increasing the alkalinity dosage ratio (amount of alkalinity to ammonia ratio, mol/mol). There is a close relationship among alkalinity, pH and the state of matter present in aqueous solution. When alkalinity was insufficient (compared to the theoretical alkalinity amount), ammonia removal efficiency increased first and then decreased at each alkalinity dosage ratio, with an abrupt removal efficiency peak. Generally, ammonia removal efficiency rose with increasing alkalinity dosage ratio. Ammonia removal efficiency reached to 88% from 23% when alkalinity addition was sufficient. Nitrite accumulation could be achieved by inhibiting nitrite oxidizing bacteria (NOB) by free ammonia (FA) in the early period and free nitrous acid in the later period of nitrification when alkalinity was not adequate. Only FA worked to inhibit the activity of NOB when alkalinity addition was sufficient.

  12. Study on Concrete Pavement Materials Using Fluidized Bed Combustion Coal Ashes%燃煤固硫灰渣混凝土路面材料研究

    Institute of Scientific and Technical Information of China (English)

    黄煜镔; 钱觉时; 张建业; 党玉栋

    2011-01-01

    Using local industrial solid waste to reduce the building cost of rural road is very important. With the experimental study on cementitious system mixed with fluidized bed combustion coal ashes, the results show that; fluidized bed combustion coal ashes have a significant pozzolanic activity due to the characteristic of porous surface and low degree of anionic polymerization, and these ashes can be organized a cementitious systems with alkali and sulfate activator,in which the fluidized bed combustion coal ashes could be up to 70%. Mixing cement and increasing the amount of sulfate-activating agent can improve the early performance of the system significantly. Especially,the dosage of sodium sulfate must be more than 1. 5%. The properties of concrete mixed with fluidized bed combustion coal ashes are suitable in terms of strength and brittleness which make it be used in the rural road successfully.%降低农村公路造价具有重要的现实意义,利用地方工业固体废弃物是一种途径.通过对燃煤固硫灰渣胶凝系统的试验研究,结果表明:燃煤固硫灰渣表面疏松和阴离子聚合度低的特征,使其具有显著的火山灰效应,可与碱、硫酸盐激发剂组成胶凝系统,其中固硫灰渣占70%以上;掺加水泥和增大硫酸盐激发剂掺量能显著改善系统早期性能,硫酸盐掺量宜大于1.5%;燃煤固硫灰渣混凝土具有较好的强度性能和材料韧性,在农村公路中应用具有现实可行性.

  13. Effect of unburned carbon content in fly ash on the retention of 12 elements out of coal-combustion flue gas

    Institute of Scientific and Technical Information of China (English)

    Lucie Barto(n)ová; Bohumír (C)ech; Lucie Ruppenthalová; Vendula Majvelderová; Dagmar Juchelková; Zdeněk Klika

    2012-01-01

    The aim of this study was to evaluate whether unburned carbon particles present in fly ash can help in the retention of S,CI,Br,As,Se,Cu,Ni,Zn,Ga,Ge,Rb,and Pb out of flue gas during the coal combustion at fluidised-bed power station where the coal was combusted along with limestone.The competitive influence of 10%-25% CaO in fly ashes on the distribution of studied elements was studied as well to be clear which factor governs behaviour of studied elements.Except of S (with significant association with CaO) and Rb and Pb (with major affinity to Al2O3) the statistically significant and positive correlation coefficients were calculated for the relations between unburned carbon content and Br (0.959),Cl (0.957),Cu (0.916),Se (0.898),Ni (0.866),As (0.861),Zn (0.742),Ge (0.717),and Ga (0.588) content.The results suggest that the unburned carbon is promising material in terms of flue gas cleaning even if contained in highly calcareous fly ashes.

  14. Dose assessment of natural radioactivity in fly ash and environmental materials from Morupule a coal-fired power station in Botswana

    International Nuclear Information System (INIS)

    This study has been undertaken to estimate the occupational and public radiation doses due to natural radioactivity at Morupule, a Coal-Fired Power Station and its environs. The radiation doses were reconstructed to include 60 year period from 1985 to 2045. Direct gamma ray spectroscopy was used to determine the natural radionuclides Th-232, U-238, and K-40 both qualitatively and quantitatively for fly ash, coal, soil and water (from the fly ash ponds) samples. The average activity concentrations for Th-232, U-238, and K-40 in fly ash samples were 64.54 Bq/kg, 49.37 Bq/kg and 40.08 Bq/kg respectively. In the case of coal, the corresponding average activity concentrations for Th-232, U-238, and K-40 were 27.43 Bq/kg, 18.10 Bq/kg and 17.38 Bq/kg respectively. For soil samples, the average activity concentrations for Th-232, U-238, and K-40 were 10.11 Bq/kg, 6.76 Bq/kg and 118.03 Bq/kg respectively. In water samples, the average activity concentrations for Th-232, U-238, and K-40 were 0.79 Bq/l, 0.32 Bq/l and 1.01 Bq/l respectively. These average activity concentrations were generally comparable to the average world activity concentrations in the case of coal samples, but were generally lower than the average world activity concentrations in the case of fly ash, soil and water samples. The average annual effective doses for the study area were estimated as 0.320 mSv, 0.126 mSv, 0.069 mSv and 0.003 mSv for fly ash, coal, soil and water samples respectively. Dose reconstruction modelling estimated the average fly ash annual effective doses for the years 1985, 1995, 2005, 2015, 2025, 2035 and 2045 to be 0.182 mSv, 0.459 mSv, 0.756 mSv, 0.320 mSv, 0.183 mSv, 0.137 mSv and 0.124 mSv respectively. The reconstructed average coal annual effective doses for similar years were 0.070 mSv, 0.182 mSv, 0.303 mSv, 0.126 mSv, 0.070 mSv, 0.060 mSv and 0.046 mSv respectively. The dose reconstruction modelling also estimated the average soil annual effective doses for the same years as

  15. Bare face red-brown bricks manufactured with fly ash from the Narcea (Asturias Coal Power Plan

    Directory of Open Access Journals (Sweden)

    Ayesta, G.

    1999-12-01

    Full Text Available Fly ash, from the Coal Power Plant of Narcea (Asturias, has been used to determine its possible use as a raw material in the bare face red-brown brick manufacture. The correct mould of a ceramic material demands a paste with an adequate plasticity. So, the optimum compositions of humidity, lubricant (talc and binder (white dextrin have been investigated. The samples were made by compressing paste into a mould using varying values of pressure and boiling temperature once the cooling speed had been established. Finally, the cooked pieces were submitted to trials demanded by the Basic Construction Norm, to see if they met the required specifications concerning Water Absorption, Suction, Contraction, Resistance to Freezing, Efflorescence and Compressive Strength.

    Se caracterizan las cenizas volantes de la Central Térmica del Narcea (Asturias para determinar su utilización como materia prima en la obtención de ladrillos cara vista. El moldeo correcto de una pieza cerámica exige trabajar una pasta con una adecuada plasticidad, para ello se investiga cuál ha de ser la composición óptima de la misma, en cuanto a: humedad, cantidad de lubricante (talco y de ligante (dextrina blanca. El conformado de las piezas o ladrillos se realiza por prensado, utilizando distintos valores de presión, así como la temperatura de cocción, una vez establecida la velocidad de enfriamiento. Finalmente, las piezas cocidas se someten a los ensayos exigidos por la Norma Básica de Edificación, para ver si cumplen las especificaciones requeridas en cuanto a: Absorción de agua. Succión, Contracción, Heladicidad, Eflorescencia y Resistencia a la compresión.

  16. Transient receptor potential vanilloid-1 (TRPV1) is a mediator of lung toxicity for coal fly ash particulate material.

    Science.gov (United States)

    Deering-Rice, Cassandra E; Johansen, Mark E; Roberts, Jessica K; Thomas, Karen C; Romero, Erin G; Lee, Jeewoo; Yost, Garold S; Veranth, John M; Reilly, Christopher A

    2012-03-01

    Environmental particulate matter (PM) pollutants adversely affect human health, but the molecular basis is poorly understood. The ion channel transient receptor potential vanilloid-1 (TRPV1) has been implicated as a sensor for environmental PM and a mediator of adverse events in the respiratory tract. The objectives of this study were to determine whether TRPV1 can distinguish chemically and physically unique PM that represents important sources of air pollution; to elucidate the molecular basis of TRPV1 activation by PM; and to ascertain the contributions of TRPV1 to human lung cell and mouse lung tissue responses exposed to an insoluble PM agonist, coal fly ash (CFA1). The major findings of this study are that TRPV1 is activated by some, but not all of the prototype PM materials evaluated, with rank-ordered responses of CFA1 > diesel exhaust PM > crystalline silica; TRP melastatin-8 is also robustly activated by CFA1, whereas other TRP channels expressed by airway sensory neurons and lung epithelial cells that may also be activated by CFA1, including TRPs ankyrin 1 (A1), canonical 4α (C4α), M2, V2, V3, and V4, were either slightly (TRPA1) or not activated by CFA1; activation of TRPV1 by CFA1 occurs via cell surface interactions between the solid components of CFA1 and specific amino acid residues of TRPV1 that are localized in the putative pore-loop region; and activation of TRPV1 by CFA1 is not exclusive in mouse lungs but represents a pathway by which CFA1 affects the expression of selected genes in lung epithelial cells and airway tissue.

  17. Performance of in-vessel composting of food waste in the presence of coal ash and uric acid

    Energy Technology Data Exchange (ETDEWEB)

    An, Chun-Jiang [Faculty of Engineering and Applied Science, University of Regina, Regina, Saskatchewan, S4S 0A2 (Canada); Huang, Guo-He, E-mail: huang@iseis.org [Faculty of Engineering and Applied Science, University of Regina, Regina, Saskatchewan, S4S 0A2 (Canada); Yao, Yao; Sun, Wei [Faculty of Engineering and Applied Science, University of Regina, Regina, Saskatchewan, S4S 0A2 (Canada); An, Kai [MOE Key Laboratory of Regional Energy Systems Optimization, S and C Academy of Energy and Environmental Research, North China Electric Power University, Beijing 102206 (China)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer The amendments of CA and UA could facilitate the composting performance. Black-Right-Pointing-Pointer The overall performance is a sum of different events with different mechanisms. Black-Right-Pointing-Pointer The added CA and UA might lead to higher pH during the composting. Black-Right-Pointing-Pointer The process is correlated with the variations of microbial activity and C/N ratio. Black-Right-Pointing-Pointer The presence of CA and UA has significant influence on composting of food waste. - Abstract: Massive quantities of food waste often coexist with other agroindustrial and industrial waste, which might contain coal ash (CA) and uric acid (UA). This study investigated the influence of CA and UA on the composting of food waste in the in-vessel system. The patterns of food waste composting were compared among various combinations. The results showed that the temperature level was enhanced in the presence of CA and UA during the first 8 days. The significant drop in pH was observed in the treatment without any amendment. But the presence of CA could alleviate the drop of pH. More intensive organic mass reduction took place in the treatments with amended CA and UA in the first half of process. The O{sub 2} uptake rate in the reactor with CA and UA was higher than that with only CA in the early stage. Both thermophilic and mesophilic microorganisms were present throughout the composting period. The populations of both thermophilic and mesophilic microorganisms were influenced when amended with CA and UA. The decreasing trend in C/N ratio was shown in all the reactors, while a relatively lower C/N ratio was obtained in the series with both CA and UA.

  18. Natural radioactivity of ground waters and soil in the vicinity of the ash repository of the coal-fired power plant ''Nikola Tesla'' A - Obrenovac (Yugoslavia)

    International Nuclear Information System (INIS)

    Radioactivity of U, Th and 40K has been tested in the vicinity of the ash repository of coal-fired power plant ''Nikola Tesla'' A in Obrenovac (Yugoslavia). By using the methods of alpha and gamma spectrometry, as well as luminescence spectrophotometry, it has been found that the ash repository is a source of radionuclides of the uranium and thorium series and spreads direction of ground waters up to a distance of several hundred metres. The influence of the repository on the soil radioactivity has been found to be minimal, whereas the balance of the first members of series (238U-234U-230Th; 232Th-228Th) has not been disturbed. (Author)

  19. Coal - proximate analysis

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-06-14

    This Standard establishes a practice for the proximate analysis of coal, that is, the coal is analysed for the content of moisture, ash and volatile matter; fixed carbon is calculated. The standard provides a basis for the comparison of coals.

  20. 粉煤灰改良粘质石灰性褐土的效应研究%Effects of Coal Ash Application on Clay Calcic Cinnamon Soils

    Institute of Scientific and Technical Information of China (English)

    李恋卿; 张俊珍; 潘根兴; 杜慧玲; 王建锁; 姚永平

    2001-01-01

    利用粉煤灰改良粘质石灰性褐土, 5年的试验结果表明,施一定量的粉煤灰,配合以复播绿肥作物压青、施无机肥等农艺措施,使土壤的质地、容重、孔隙度及土壤水分状况得到明显改善,增强土壤微生物活性,提高土壤养分有效库容。试验推荐最佳方案为,公顷施粉煤灰 35.25万 kg、硝酸磷肥 880.5 kg,绿肥 13 047 kg,作物产量可达 6 000 kg· hm- 2。%A five- year field experiment was carried out on clay-calcic cinnamon soils for studying effects of applying coal ash, green manurie and chemical fertilizer on clay-calcic cinnamon soil.The results showed that application of coal ash was capable of improving the soil properties such as porosity, texture volumetric weight,availability of nutrients and microbial activity. It was optimized that a protocol with application of coal ash. nitro-phosphate 880.5 kg· hm- 2 and green manure 13 t could produce as high as 6 t of wheat with net increase of 400 kg per hectare.

  1. Study on Effect and Catalytic Mechanism of the Catalysts for Coal Oxidation in Alkaline Medium%Study on Effect and Catalytic Mechanism of the Catalysts for Coal Oxidation in Alkaline Medium

    Institute of Scientific and Technical Information of China (English)

    刘怀有; 吕经康; 赵永刚; 周尉; 印仁和

    2011-01-01

    Coal electro-oxidation in sodium hydroxide solution with catalysts, K3Fe(CN)6, sodium hypochlorite and sup- ported FeS, were investigated, respectively. Gas produced from electro-analysis of coal slurry was collected by drainage-method and l-t curves were recorded to testify the catalysis of each catalyst for coal oxidation. The results show that the three kinds of catalysts can obviously improve the coal oxidation current. Furthermore, K3Fe(CN)6 and sodium hypochlorite played an indirect oxidation role in the electrolysis process. Catalysts bridge the coal par- ticles and the solid electrode surface, thus increase the coal oxidation rates. The changes of catalyst content during the electrolysis were further determined by quantitative titration to discuss the catalytic Mechanism. The dynamic transition of K3Fe(CN)6/K4Fe(CN)6 and ClO^-/Cl^- are proposed by iodometric method.

  2. 助熔剂对煤灰熔点的影响%A Study of the Influence of Fluxes on the Coal Ash Fusion Point

    Institute of Scientific and Technical Information of China (English)

    张艳敏

    2015-01-01

    This study aims at finding out the influence of three fluxes including CaCO3 ,MgO,and Fe2 O3 on the coal ash fusion point when they are mixed with of different mass ratios with the ash.The results show that the coal ash fusion point drops differently when different amount of the three fluxes is added to it under the weak reducing atmosphere; the ash gets its lowest fusion point when the amount of the three agents mounts to 23%of the total is added to;and the point begins to rise when the amount of the fluxes is greater than 23%.Compared with three samples in which the same amount of the three agents is added separately to the same amount of the ash,it shows that Fe2 O3 decreases the ash fusion point much more than CaCO3 and MgO do.It is then concluded that Fe2 O3 is more workable than the other two as a flux agent.%通过添加 CaCO3、MgO、Fe2 O3三种助熔剂,按不同质量比与煤灰混合,考察其对煤灰熔点的影响。结果表明:在弱还原性气氛下,添加一定量的助熔剂 CaCO3、MgO 和 Fe2 O3可使煤的灰熔点有不同程度的降低,当CaCO3、MgO和 Fe2 O3在煤灰中的含量占23%左右时灰熔点最低,继续添加则使煤灰熔点又开始上升。煤灰中助熔剂含量相同时,比较三种助熔剂的助熔效果,可以看出在还原性气氛条件下助熔剂 Ca-CO3、MgO对灰熔点影响较小,而 Fe2O3对灰熔点影响较大,因此最适合做助熔剂的是 Fe2O3,CaCO3、MgO不适合做助熔剂。

  3. Pilot Demonstration of Technology for the Production of High Value Materials from the Ultra-Fine (PM2.5) Fraction of Coal Combustion Ash

    Energy Technology Data Exchange (ETDEWEB)

    T. L. Robl; J. G. Groppo; R. Rathbone; B. Marrs; R. Jewell

    2008-07-18

    polyethylene terphthalate filled polymers were prepared and subjected to SEM analysis to verify that the UFA was well dispersed. The addition of fillers increased the modulus of the HDPE composite, but decreased both the offset yield stress and offset yield strain, showing that the fillers essentially made the composite stiffer but the transition to plastic deformation occurred earlier in filled HDPE as stress was applied. Similar results were obtained with TPE, however, the decrease in either stress or strain at offset yield were not as significant. Dynamic mechanical analyses (DMA) were also completed and showed that although there were some alterations in the properties of the HDPE and TPE, the alterations are small, and more importantly, transition temperatures are not altered. The UFA materials were also tested in expanded urethanes, were improvements were made in the composites strength and stiffness, particularly for lighter weight materials. The results of limited flammability and fire safety testing were encouraging. A flowsheet was developed to produce an Ultra-Fine Ash (UFA) product from reclaimed coal-fired utility pond ash. The flowsheet is for an entry level product development scenario and additional production can be accommodated by increasing operating hours and/or installing replicate circuits. Unit process design was based on experimental results obtained throughout the project and cost estimates were derived from single vendor quotes. The installation cost of this plant is estimated to be $2.1M.

  4. Radon exhalation of cementitious materials made with coal fly ash: Part 1 - scientific background and testing of the cement and fly ash emanation

    International Nuclear Information System (INIS)

    Increased interest in measuring radionuclides and radon concentrations in fly ash, cement and other components of building products is due to the concern of health hazards of naturally occurring radioactive materials (NORM). The current work focuses on studying the influence of fly ash (FA) on radon-exhalation rate (radon flux) from cementitious materials. The tests were carried out on cement paste specimens with different FA contents. The first part of the paper presents the scientific background and describes the experiments, which we designed for testing the radon emanation of the raw materials used in the preparation of the cement-FA pastes. It is found that despite the higher 226Ra content in FA (more than 3 times, compared with Portland cement) the radon emanation is significantly lower in FA (7.65% for cement vs. 0.52% only for FA)

  5. Sulfur removal from lignite by oxydesulfurization using fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Yaman, S.; Kucukbayrak, S. [Istanbul Technical University, Istanbul (Turkey). Chemical Engineering Dept.

    1997-01-01

    Since fly ash contains alkaline oxides, it is possible to use its water-extractable components as a desulfurization agent. This was investigated using some high-sulfur Turkish lignites. The effects of the amount of fly ash used, temperature, partial pressure of oxygen and time were studied in the range 5-40 g, 403-498 K, 0.0-1.5 MPa and 15-90 min respectively. The extents of pyritic and organic sulfur removal and recoveries of coal and calorific value were investigated for each of these variables. Reactivity and some combustion characteristics (ignition temperature, end temperature of combustion and combustion rate) of original and desulfurzed lignite samples were compared using combustion curves obtained from thermogravimetric analysis (t.g.a) results. FT-i.r. spectroscopy was used to determine the effects of the desulfurization process on the coal structure. 5 refs., 6 figs.,4 tabs.

  6. Preparation, transport and disposal of ash from coal-fired power plant Kosovo B in the form of dense hydromixture; Priprema, transport i deponovanje pepela termoelektrane Kosovo B u vidu guste hidromesavine

    Energy Technology Data Exchange (ETDEWEB)

    Drazovic, D.; Markovic, Z.; Stjepanovic, P.; Todorovtc, D. [Rudarski Institute, Beograd (Yugoslavia)

    1999-07-01

    The transportation of ash and slag from coal-fired power plants is mainly hydraulic. Until the eighties the most frequently applied technology was the transportation of ash and slag in the form of diluted hydromixture (concentration of solids below 10%). This method of ash and slag transportation became a rule in Yugoslavia's coal-fired power plants. It was not until 1988 that the transportation of dense hydromixture was introduced in the coal-fired power plant Gacko. This technology was not applied on account of its transportation advantages, but due to specific ash features that determine the conditions of disposal. Namely, the density of hydromixture is important for the solidification of disposed material. Considering the chemical and mineralogical properties of ash the same system was applied in the coal-fired power plant Kosovo B. In this paper two technological lines were installed and put to use in actual industrial conditions, and the results obtained indicate that all the designed parameters have been confirmed in practice and that the application of this technology has proven to be profitable in many ways. 7 refs., 8 figs., 13 tabs.

  7. 煤体灰分与挥发分对煤吸附甲烷性能的影响实验研究%Experimental Study on Influence of Coal Ash Content and Volatile Matter upon Its Methane Adsorption Capability

    Institute of Scientific and Technical Information of China (English)

    李树刚; 胡魏魏; 林海飞; 赵鹏翔; 魏宗勇

    2015-01-01

    为研究煤体灰分、挥发分对煤吸附甲烷性能的影响,运用高容量吸附装置测定同一煤矿不同灰分、挥发分煤样的等温吸附曲线和吸附常数a、b值,并运用SPSS多元线性回归软件进行分析。实验结果表明:不同灰分、挥发分煤样的等温吸附曲线符合Langmuir方程,且二者对于煤吸附甲烷性能均有一定的影响。煤灰分不变时,吸附常数a值随挥发分的增大而线性递增,吸附常数b值随挥发分的增大而线性递减;煤挥发分不变时,a值随灰分的增大而线性递增,b值随灰分的增大而线性递减。研究结果为准确测定煤层瓦斯含量、瓦斯压力等参数提供了一定的理论依据。%In order to study the influence of coal ash content and volatile matter on the coal methane absorption capability, measurement was carried out on the isothermal adsorption curve and the adsorption constants a and b of the coal samples from one coal mine and with different ash content and volatile matter by using a high-capacity adsorption device in the laboratory, and analysis was made on them with the multiple linear regression software SPSS. The experimental results showed that the isothermal adsorption curve of coal samples with different coal ash content and volatile matter well fit the Langmuir equation,and both had a certain influence on the coal methane adsorption performance;when the coal ash content was constant,the adsorption constants a increased linearly with the increase of volatile matter,but the constant b decreased linearly with the increase of volatile matter;and when the volatile matter was constant,the adsorption constants a increased linearly with the increase of coal ash content,but the constant b decreased linearly with the increase of the coal ash content. This research results provided a certain theoretical basis for the accurate determination of the parameters such as coal-seam gas content and gas pressure.

  8. Reducing carbon-in-ash

    Energy Technology Data Exchange (ETDEWEB)

    Nigel S. Dong [IEA Clean Coal Centre, London (United Kingdom)

    2010-05-15

    High levels of carbon-in-ash lead to reduced power plant efficiency and higher fuel costs, degrade the performance of electrostatic precipitators and increase emissions of particulates. Increased carbon levels in the fly ash can lead to problems with ash use in cement/concrete production. This report reviews current measures and technologies that can be used to prevent excessive carbon-in-ash in pulverised coal combustion (PCC) power plants. These include coal cleaning, coal fineness improvement, reduction of distribution imbalance of coal among burners, increasing coal-air mixing rates at both burner and OFA levels and optimising excess air ratios. A plasma-assisted combustion enhancement technology can help achieve better ignition and more stable flame for coals that are normally difficult to burn. Computer-based combustion optimisation using expert systems, neural network systems and coal combustion simulation is becoming an invaluable means to tackle the carbon-in-ash issue. This report also reviews the regulations in nine major coal-consuming countries, which stipulate the maximum unburnt carbon levels permitted for fly ash for use in concrete/cement production. The Loss on Ignition (LOI) parameter is used in all national standards, although it is considered inadequate and may exclude some usable fly ash from being utilised. Performance-based regulations are more appropriate and have been adopted by Canada and USA. The EU and Canada now permit the use of fly ash produced from co-combustion of coal and biomass. China and Russia allow very high LOI levels for certain fly ash but the other countries require similar LOI limits for fly ash for use in concrete. Finally, this report discusses measures and technologies for reduction of carbon-in-ash, including classification, froth flotation, triboelectrostatic separators, thermal processes and carbon surface modification. 146 refs., 19 figs., 15 tabs.

  9. Reduction in CO{sub 2} emission from normal and saline soils amended with coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Sang-Sun; Choi, Woo-Jung; Lee, Kwang-Seung [Chonnam National Univ., Gwangju (Korea, Republic of). Dept. of Rural and Bio-Systems Engineering; Ro, Hee-Myong [Seoul National Univ., Seoul (Korea, Republic of). Dept. of Agricultural Biotechnology

    2012-10-15

    Fly ash can reduce CO{sub 2} emission from soils via biochemical (i.e., inhibition of microbial activity) and physicochemical (i.e., carbonation) mechanisms. This study investigated the effects of fly ash amendment on biochemical and physicochemical reduction in CO{sub 2} emission from normal and saline soils. The physicochemical mechanisms of reduction in CO{sub 2} emission by fly ash were estimated in a batch experiment with carbonate solution as a CO{sub 2} source by the scanning electron microscope (SEM) and inductively coupled plasma analyses. Biochemical mechanisms of reduction in CO{sub 2} emission by fly ash were investigated in a 3-day laboratory incubation experiment with normal and saline soils in the absence and presence of fly ash. Finally, the effects of fly ash amendment at a variety rate from 2 to 15 % (w/w) on CO{sub 2} emission from normal and saline soils in the presence of additional organic carbon source (glucose) were investigated through a 15-day laboratory incubation study. In the batch experiment with carbonate solution, both the SEM image of fly ash and changes in soluble Ca and Mg concentrations during reaction with carbonate suggested that the formation of CaCO{sub 3} and MgCO{sub 3} via carbonation was the principal physicochemical mechanism of carbonate removal by fly ash. In the 3-day incubation study conducted to examine biochemical mechanisms of reduction in CO{sub 2} emission by fly ash, microbial respiration of saline soil was inhibited (P < 0.05) by fly ash due to high pH, salinity, and boron concentration of fly ash; meanwhile, for normal soil, there was no inhibitory effect of fly ash on microbial respiration. In the 15-day incubation with glucose, fly ash application at a variety rates from 2 to 15 % (w/w) reduced CO{sub 2} emission by 3.6 to 21.4 % for normal and by 19.8 to 30.3 % for saline soil compared to the control without fly ash. For saline soil, the reduction in CO{sub 2} emission was attributed primarily to

  10. Microwave assisted aqua regia extraction of thallium from sediment and coal fly ash samples and interference free determination by continuum source ETAAS after cloud point extraction.

    Science.gov (United States)

    Meeravali, Noorbasha N; Madhavi, K; Kumar, Sunil Jai

    2013-01-30

    A simple cloud point extraction method is described for the separation and pre-concentration of thallium from the microwave assisted aqua regia extracts of sediment and coal fly ash samples. The method is based on the formation of extractable species of thallium and its interaction with hydrophobic solubilizing sites of Triton X-114 micelles in the presence of aqua regia and electrolyte NaCl. These interactions of micelles are used for extraction of thallium from a bulk aqueous phase into a small micelles-rich phase. The potential chloride interferences are eliminated effectively, which enabled interference free determination of thallium from aqua regia extracts using continuum source ETAAS. The parameters affecting the extraction process are optimized. Under the optimized conditions, pre-concentration factor and limit of detection are 40 and 0.2 ng g(-1), respectively. The recoveries are in the range of 95-102%. A characteristic mass, 13 pg was obtained. The accuracy of the method is verified by analyzing certified reference materials such as NIST 1633b coal fly ash, NIST 1944 marine sediment and GBW 07312 stream sediments. The results obtained are in good agreement with the certified values and method is also applied to real samples.

  11. Evaluation of erosion-oxidation and ash deposition in the convective section of an industrial watertube boiler retrofitted to fire coal-water fuel

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Jianyang; Walsh, P.M.; Miller, B.G.; Scaroni, A.W. [Pennsylvania State Univ., University Park, PA (United States)

    1994-12-31

    The feasibility of directly firing coal-water fuel in an oil-designed industrial watertube boiler is being determined for possible deployment at Department of Defense facilities. Erosion of carbon steel by particles and deposition of ash were measured in the convective section of the boiler while cofiring coal-water fuel and natural gas. Erosion was enhanced by directing a small jet of nitrogen, air, or oxygen toward the surface of a test coupon mounted on an air-cooled tube. The temperature and oxygen dependencies of the erosion rate were explained by a model for simultaneous erosion and oxidation. Extrapolation, using the experimentally determined coefficients for metal and oxide erosion, provided estimates of the erosion rate as functions of the gas velocity and angular position about the circumference of a heat exchanger tube in the convective section of the boiler. Under the conditions of metal temperature, oxygen concentration in the gas, particle size, and particle loading investigated, erosion of carbon steel is expected to be slower than 0.05 {mu}m/hour when the gas velocity in the convection section is less than approximately 8 m/s. A measurement in the convective section at 4 m/s gas velocity showed a pattern of ash deposits covering the circumference at positions on the tube surface where no erosion is predicted.

  12. Production of lightweight aggregates from coal fly ash and municipal wastewater sludge; Produktion af letvaegtsklinker paa baggrund af aske med et hoejt restkulindhold og spildevandsslam fra kommunale rensningsanlaeg

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-12-01

    The municipalities have difficulties in disposing the wastewater sludge. To use wastewater sludge in agriculture limit values for the content of hazardous substanceshave have been established. These limit values have been tightened in 2000, and the municipalities therefore need alternative ways of disposal. Wastewater sludge combusted in solid waste incineration plants will result in slag corresponding to 40-45% solid matter, mainly sand. Wastewater sludge used as additive in production of light clinkers, gives 100% utilization of the sludge. This project uses wet wastewater sludge, which means that the municipalities do not need to invest in new natural gas fired drying plants. USA has for many years had a similar production, and in Denmark Aalborg Portland Cement uses 7.500 tons of wastewater sludges (100% solid matter) annually in the cement production. Satisfactory laboratory tests and full scale tests on a Danish plant, Hingevaerket, is carried out. For the full scale tests about 40 tons of sludge and about 30 tons of coal fly ash were used. Washing out tests with the new light clinkers have been carried out, and the result was acceptable. Furthermore, the flue gas was analysed for content of mercury before and after the full scale test. Thus there are no insoluble technical problems in relation to addition of wastewater sludge and coal fly ash. (EHS)

  13. Abundances and distribution of minerals and elements in high-alumina coal fly ash from the Jungar Power Plant, Inner Mongolia, China

    Science.gov (United States)

    Dai, S.; Zhao, L.; Peng, S.; Chou, C.-L.; Wang, X.; Zhang, Y.; Li, D.; Sun, Y.

    2010-01-01

    The fly ash from the Jungar Power Plant, Inner Mongolia, China, is unique because it is highly enriched in alumina (Al2O3>50%). The fly ash mainly consists of amorphous glass and mullite and trace amounts of corundum, quartz, char, calcite, K-feldspar, clay minerals, and Fe-bearing minerals. The mullite content in fly ash is as high as 37.4% because of high boehmite and kaolinite contents in feed coal. Corundum is a characteristic mineral formed during the combustion of boehmite-rich coal.Samples from the economizer were sieved into six size fractions (500 mesh) and separated into magnetic, mullite+corundum+quartz (MCQ) and glass phases for mineralogical and chemical analysis. The corundum content increases but amorphous glass decreases with decreasing particle size. Fractions of small particle sizes are relatively high in mullite, probably because mullite was formed from fine clay mineral particles under high-temperature combustion condition. Similarly, fine corundum crystals formed in the boiler from boehmite in feed coal. The magnetic phase consists of hematite, magnetite, magnesioferrite, and MgFeAlO4 crystals. The MCQ phase is composed of 89% mullite, 6.1% corundum, 4.5% quartz, and 0.5% K-feldspar.Overall, the fly ash from the power plant is significantly enriched in Al2O3 with an average of 51.9%, but poor in SiO2, Fe2O3, CaO, MgO, Na2O, P2O5, and As. Arsenic, TiO2, Th, Al2O3, Bi, La, Ga, Ni, and V are high in mullite, and the magnetic matter is enriched in Fe2O3, CaO, MnO, TiO2, Cs, Co, As, Cd, Ba, Ni, Sb, MgO, Zn, and V. The remaining elements are high in the glass fraction. The concentration of K2O, Na2O, P2O5, Nb, Cr, Ta, U, W, Rb, and Ni do not clearly vary with particle size, while SiO2 and Hg decrease and the remaining elements clearly increase with decreasing particle size. ?? 2009 Elsevier B.V.

  14. Abundances and distribution of minerals and elements in high-alumina coal fly ash from the Jungar Power Plant, Inner Mongolia, China

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Shifeng [State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology (Beijing), D 11, Xueyuan Road, Haidian District, Beijing 100083 (China); Department of Resources and Earth Science, China University of Mining and Technology, D11, Xueyuan Road, Haidian District, Beijing 100083 (China); Zhao, Lei; Wang, Xibo; Zhang, Yong; Li, Dan; Sun, Yingying [Department of Resources and Earth Science, China University of Mining and Technology, D11, Xueyuan Road, Haidian District, Beijing 100083 (China); Peng, Suping [State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology (Beijing), D 11, Xueyuan Road, Haidian District, Beijing 100083 (China); Chou, Chen-Lin [Illinois State Geological Survey (emeritus), University of Illinois, 615 East Peabody Drive, Champaign, IL 61820 (United States)

    2010-04-01

    The fly ash from the Jungar Power Plant, Inner Mongolia, China, is unique because it is highly enriched in alumina (Al{sub 2}O{sub 3} > 50%). The fly ash mainly consists of amorphous glass and mullite and trace amounts of corundum, quartz, char, calcite, K-feldspar, clay minerals, and Fe-bearing minerals. The mullite content in fly ash is as high as 37.4% because of high boehmite and kaolinite contents in feed coal. Corundum is a characteristic mineral formed during the combustion of boehmite-rich coal. Samples from the economizer were sieved into six size fractions (< 120, 120-160, 160-300, 300-360, 360-500, and > 500 mesh) and separated into magnetic, mullite + corundum + quartz (MCQ) and glass phases for mineralogical and chemical analysis. The corundum content increases but amorphous glass decreases with decreasing particle size. Fractions of small particle sizes are relatively high in mullite, probably because mullite was formed from fine clay mineral particles under high-temperature combustion condition. Similarly, fine corundum crystals formed in the boiler from boehmite in feed coal. The magnetic phase consists of hematite, magnetite, magnesioferrite, and MgFeAlO{sub 4} crystals. The MCQ phase is composed of 89% mullite, 6.1% corundum, 4.5% quartz, and 0.5% K-feldspar. Overall, the fly ash from the power plant is significantly enriched in Al{sub 2}O{sub 3} with an average of 51.9%, but poor in SiO{sub 2}, Fe{sub 2}O{sub 3}, CaO, MgO, Na{sub 2}O, P{sub 2}O{sub 5}, and As. Arsenic, TiO{sub 2}, Th, Al{sub 2}O{sub 3}, Bi, La, Ga, Ni, and V are high in mullite, and the magnetic matter is enriched in Fe{sub 2}O{sub 3}, CaO, MnO, TiO{sub 2}, Cs, Co, As, Cd, Ba, Ni, Sb, MgO, Zn, and V. The remaining elements are high in the glass fraction. The concentration of K{sub 2}O, Na{sub 2}O, P{sub 2}O{sub 5}, Nb, Cr, Ta, U, W, Rb, and Ni do not clearly vary with particle size, while SiO{sub 2} and Hg decrease and the remaining elements clearly increase with decreasing

  15. Removal of 2,4-dichlorophenol and pentachlorophenol from waters by sorption using coal fly ash from a Portuguese thermal power plant

    Energy Technology Data Exchange (ETDEWEB)

    Estevinho, Berta N. [LEPAE, Departamento de Engenharia Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Martins, Isabel [LEPAE, Departamento de Engenharia Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Ratola, Nuno [LEPAE, Departamento de Engenharia Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Alves, Arminda [LEPAE, Departamento de Engenharia Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Santos, Lucia [LEPAE, Departamento de Engenharia Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal)]. E-mail: lsantos@fe.up.pt

    2007-05-08

    Chlorophenols are one of the most important groups of priority pollutants, due to their high toxicity, mutagenicity and carcinogenicity. Although activated carbon has been the preferred choice for the removal of such pollutants from wastewaters, the search for cheaper alternative sorbents became common in the last years. Fly ash, a by-product from coal burning power plants, has a surface composition that may enable the sorption of specific organic compounds. Therefore, this feasibility study presents the optimization of the operating parameters of a fixed-bed column containing fly ash particles, percolated by aqueous solutions of 2,4-dichlorophenol (2,4-DCP) and pentachlorophenol (PCP) with concentrations of 1 and 100 {mu}g/ml. Both chlorophenols were analysed by gas chromatography with electron capture detection (GC-ECD), after solid-phase microextraction (SPME), with limits of detection (LODs) of 7.28 {mu}g/l for 2,4-DCP and 1.76 {mu}g/l for PCP. Removal efficiencies above 99% were obtained for an initial concentration of 10 {mu}g/ml of chlorophenols. Column saturation was achieved after 7 h of continuous operation for 2,4-DCP and 10 h for the PCP for feed levels of 10 {mu}g/ml. Fly ash exhibited more affinity towards the sorption of PCP, in comparison to 2,4-DCP.

  16. Study of Compressive Strength of Concrete with Coal Power Plant Fly Ash as Partial Replacement of Cement and Fine Aggregate

    OpenAIRE

    FAREED AHMED MEMON; NAFEES AHMED MEMON; RIZWAN ALI MEMON

    2010-01-01

    This research study comprises of concrete cubes made with Ordinary Portland Cement and with different configurations of fly ash by replacing cement and fine aggregate. To achieve the aim of this study, total 81 concrete cubes were cast. Among 81 cubes, 9 cubes were made with normal concrete, 36 cubes were made by replacing 25%, 50%, 75% and 100% of fine aggregate with fly ash and 36 cubes were made by replacing 10%, 25%, 50%, and 75% of cement with fly ash. The cubes were 6\\" x 6\\" in cross-s...

  17. Shedding of ash deposits

    DEFF Research Database (Denmark)

    Zbogar, Ana; Frandsen, Flemming; Jensen, Peter Arendt;

    2009-01-01

    Ash deposits formed during fuel thermal conversion and located on furnace walls and on convective pass tubes, may seriously inhibit the transfer of heat to the working fluid and hence reduce the overall process efficiency. Combustion of biomass causes formation of large quantities of troublesome....... Low melting temperatures make straw ashes especially troublesome, since their stickiness is higher at lower temperatures, compared to coal ashes. Increased stickiness will eventually lead to a higher collection efficiency of incoming ash particles, meaning that the deposit may grow even faster...

  18. Assessing the environmental impacts of using demineralized coal for electricity generation

    DEFF Research Database (Denmark)

    Ryberg, Morten; Owsianiak, Mikolaj; Laurent, Alexis

    2014-01-01

    The energy sector is the source of two-thirds of global greenhouse-gas emissions, and is the main target ofclimate policies among authorities and governments. The share of fossil coals (hard coal and lignite) in world total net electricity generation is 40% in 2010. Demineralization or ash removal...... in alkaline and acidic solution to dissolve and remove the ash. This process is well-studied on lab scale but has only to a small extent been tried on a full scale. This assessment is conducted as an aid for further developing thetechnology, allowing for early identification of environmental impacts...

  19. Study of Compressive Strength of Concrete with Coal Power Plant Fly Ash as Partial Replacement of Cement and Fine Aggregate

    Directory of Open Access Journals (Sweden)

    FAREED AHMED MEMON

    2010-10-01

    Full Text Available This research study comprises of concrete cubes made with Ordinary Portland Cement and with different configurations of fly ash by replacing cement and fine aggregate. To achieve the aim of this study, total 81 concrete cubes were cast. Among 81 cubes, 9 cubes were made with normal concrete, 36 cubes were made by replacing 25%, 50%, 75% and 100% of fine aggregate with fly ash and 36 cubes were made by replacing 10%, 25%, 50%, and 75% of cement with fly ash. The cubes were 6\\" x 6\\" in cross-section, and the mix design was aimed for 5000 psi. After proper curing of all 81 cubes, they were tested at 3, 7 and 28 days curing age. The cubes were tested in Forney Universal Testing Machine. By analyzing the test results of all the concrete cubes, the following main findings have been drawn. The compressive strength of concrete cubes made by replacing 100 % fine aggregate by fly ash was higher than the concrete cubes made with Ordinary Portland Cement at all 3, 7 and 28 days curing ages. On the other hand, the compressive strength of concrete cubes made by replacing 10 % and 25 % cement by fly ash was slightly lower than the concrete cubes made with Ordinary Portland Cement at all curing ages, whereas, the compressive strength of concrete cubes made by replacing 50 % and 75 % of cement by fly ash were quite lower than the concrete cubes made with Ordinary Portland Cement at all curing ages.

  20. Removal of uranium and gross radioactivity from coal bottom ash by CaCl2 roasting followed by HNO3 leaching

    International Nuclear Information System (INIS)

    Highlight: • Roasting the ash with CaCl2 enhanced the removal of uranium and gross radioactivity. • 87.3% of the total uranium was removed via the optimized roast-leach process. • Nearly 90% of gross α and β radioactivity was removed via the roast-leach process. • Molten CaCl2 promoted the incorporation of Ca and Al into Si-O matrices in ash. • Radionuclides were removed by the acid decomposition of newly formed silicates. - Abstract: A roast-leach method using CaCl2 and HNO3 to remove uranium and gross radioactivity in coal bottom ash was investigated. Heat treatment of the ash with 100% CaCl2 (900 °C, 2 h) significantly enhanced uranium leachability (>95%) compared with direct acid-leaching (22.6–25.5%). The removal efficiency of uranium and gross radioactivity increased steeply with increasing CaCl2 content, from 10% to 50%, and a HNO3 leaching time from 5 min to 1 h, but remained nearly constant or decreased slightly with increasing CaCl2 dosage >50% or acid-leaching time >1 h. The majority of the uranium (87.3%), gross α (92.9%) and gross β (84.9%) were removed under the optimized roast-leach conditions (50% CaCl2, 1 M HNO3 leaching for 1 h). The mineralogical characteristics of roasted clinker indicated that molten CaCl2 promoted the incorporation of Ca into silica and silicates and resulted in its progressive susceptibility to acid attack. Uranium and other radionuclides, most likely present in the form of silicates or in association with miscellaneous silicates in the highest density fraction (>2.5 g mL−1), were probably leached out as the result of the acid decomposition of newly formed “gelatinizing silicates”

  1. Evaluation and demonstration of remediation alternatives for historical mine waste using ash and alkaline by products; Utvaerdering och demonstration av efterbehandlingsalternativ foer historiskt gruvavfall med aska och alkaliska restprodukter

    Energy Technology Data Exchange (ETDEWEB)

    Baeckstroem, Mattias; Sartz, Lotta; Karlsson, Stefan (MTM, Man-Technology-Envionrment, Oerebro Univ., 701 82 Oerebro (Sweden))

    2009-03-15

    The results clearly show that the use of alkaline by products can significantly reduce the leakage of trace metals from historical acid mine waste. Under ideal conditions (laboratory experiments) pH increase significantly and the trace metal concentrations decrease with around 99% compared to the untreated reference. During more realistic conditions (pilot scale) the same increase in pH was not obtained and thus the decrease in trace metal concentrations was not as great. In the stabilisation experiments pH was between 5.8 and 6.8 while the trace metal reduction was around 96-99%. In the filter experiments a median pH between 4 (aged ash) and 10 (lime kiln dust) was obtained after the alkaline section. Average metal reduction is around 95% for cadmium, copper and lead while it is slightly lower for zinc (85%). In summary it is indicated that hydroxide dominated materials work best in aerated environments while carbonate dominated materials work best in reducing environments. In summary it can be concluded that the use of alkaline by products to neutralise acidic mine waste and acid mine drainage from historical mine sites give rise to both environmental and economical benefits and should therefore be encouraged as a sustainable remediation method

  2. Preservation of natural aquatic ecosystems by application of bottom coal ash based bioreactor for in situ treatment of anthropogenic effluents

    Science.gov (United States)

    Anker, Y.; Nisnevitch, M.; Tal, M.; Cahan, R.; Michael, E.

    2012-12-01

    One consequence of global climate change is recharge decrease at sub tropical and Mediterranean regions to both the surface and the ground fresh water resources. As a general rule, when water source quantity is reduced, the level of salination, as well as chemical and biological pollutants, tends to increase. The situation is more severe whenever the drainage basin is (a) heavily populated from urban, industrial and agricultural areas, (b) has wide areas of thin or non soil cover and (c) has a karstic structure and morphology. These latter conditions are typical to many regions around the Middle East; whereas pollution hazard to Mid Eastern streams is greater than to those in more humid regions owing to their relative small size and poor dilution capacity. The consequence of this ongoing and increasing anthropogenic pollution is endangerment of natural aquatic habitats and due to decrease in fresh water supply availability also to human sustainability. The ecological impact may involve transition of ephemeral (Wadi) streams into intermittent ones with the accompanied biodiversity change or extinction once the pollution is extreme. The impact on indigenous human communities might be as severe owing to drinking water quality decrease and the consequent decrease id quantity as well as damage to dryland farming. In setting of operations applied to the Yarkon Taninim watershed (central Israel) management, a pilot biofilter facility for sustainable preservation and rehabilitation of natural fluvial ecosystems was tested. This biofilter is planned to operate through low impact concept assimilating natural treatment processes occurring during runoff recharge through a porous flow media. The facility is constructed out of several grain sizes of bottom coal ash aggregate, which was found to be a better microbial mats growing stratum, compared to common natural aggregates such as tuff and lime pebbles (and also has an EPA directive for wastewater treatment). The biofilter is

  3. Treatment of Cu-containing wastewater by activated carbon/coal fly ash%活性炭/粉煤灰处理含铜废水的研究

    Institute of Scientific and Technical Information of China (English)

    黄晓丹; 薛美香; 李先学

    2015-01-01

    采用活性炭/粉煤灰处理模拟含铜废水,考察pH、吸附时间、吸附温度、投加量、质量比、活性炭、粉煤灰粒径、铜离子浓度等对吸附效果的影响。结果表明,单纯粉煤灰的吸附效果较差,但100目的粉煤灰与100目的活性炭混合,其吸附效果接近于纯活性炭。活性炭/粉煤灰处理100 mL、30 mg/L模拟含铜废水的最佳吸附条件为:吸附时间3 h,pH 6,吸附温度45℃,活性炭/粉煤灰(质量比1∶1)投加量2.5 g,活性炭和粉煤灰粒径均为100目。在此条件下,铜离子去除率可达97.33%,处理后水中铜离子浓度(0.8114 mg/L)低于国家二级排放标准(1.0 mg/L)。%Cu-containing wastewater was treated by activated carbon/coal fly ash and the impact of solu-tion pH value, adsorption time, temperature, the dosage, the mass ratio, particle size of activated carbon and coal fly ash,and concentration of copper ions on the Cu adsorption capacity were investigated. Results showed that the adsorption effect of copper ion by coal fly ash alone was poor,but when 100 mesh coal fly ash mixed with 100 mesh activated carbon, the adsorption effect was closed to pure activated carbon. 100 mL 30 mg/L simulated Cu-containing wastewater the best adsorption conditions of activated carbon/coal fly ash were pH value of 6,the 2. 5 g dosage of activated carbon/coal fly ash(mass ratio of 1∶1),ac-tivated carbon/coal fly ash particle size of 100 mesh after 3 h contacting at 45℃. Under these conditions, the removal rate of copper ion can reach 97. 33%,and the copper ions concentration(0. 811 4 mg/L) in the treated water were lower than the national emission standards(1. 0 mg/L).

  4. Coal

    International Nuclear Information System (INIS)

    Coal world production represents 3.5 billions of tons, plus 900 millions of tons of lignite. 50% of coal is used for power generation, 16% by steel making industry, 5% by cement plants, and 29% for space heating and by other industries like carbo-chemistry. Coal reserves are enormous, about 1000 billions of tons (i.e. 250 years of consumption with the present day rate) but their exploitation will be in competition with less costly and less polluting energy sources. This documents treats of all aspects of coal: origin, composition, calorific value, classification, resources, reserves, production, international trade, sectoral consumption, cost, retail price, safety aspects of coal mining, environmental impacts (solid and gaseous effluents), different technologies of coal-fired power plants and their relative efficiency, alternative solutions for the recovery of coal energy (fuel cells, liquefaction). (J.S.)

  5. Charge performance for co-combustion ash of biomass and coal%煤与生物质混烧灰荷电特性研究

    Institute of Scientific and Technical Information of China (English)

    吕建燚; 邓晓川; 陆义海; 付丽丽; 胡志光; 徐冰漪

    2016-01-01

    对玉米秸分别与两种煤以不同比例混烧生成的混烧灰进行了荷电特性研究。利用法拉第杯荷电量检测系统和静电低压撞击器( ELPI)测量了混烧灰的总体荷质比及分级荷质比,并借助于成分分析及形貌分析结果讨论了其影响机理。结果表明,随着生物质掺入量在混烧燃料中的增加,混烧灰的成分组成发生变化,使得其介电常数变大,比电阻增大,表面吸附能力增强,从而使混烧灰的总体荷质比有一定的上升趋势。对混烧灰的分级荷质比测量结果表明,排除灰样粒径的影响,生物质的掺入使得混烧灰的荷电能力得以增强,但影响相对较小,颗粒粒径是影响混烧灰荷电能力的主要因素。%The charge performance of ash generated from co-combustion of different types of coals and biomass fuel ( corn stalk ) was studied using faraday-cup detector and electrical low pressure impactor ( ELPI ) . The results show that the charge capacity of co-combustion ash rises a little with the increase of biomass in fuel mixture. The reason is that different types of co-combustion ash have different chemical compositions and structural features. This improves the relative dielectric constant, specific resistance and surface adsorptive ability, and thus promotes the charge performance of co-combustion ash. Although the addition of biomass in fuel mixture raises the charge capacity of co-combustion ash, particle size is still the main influence factor on its charge performance.

  6. Fly ash grouts for remediation of acid mine drainage

    International Nuclear Information System (INIS)

    An engineering investigation into the use of electric utility wastes for grouting acidic mine spoil resulting from coal extraction has been undertaken. Laboratory investigations into the physical and chemical properties of various grout mixtures and grouted spoil materials are underway. Grout mixtures are placed in columns and permeated with distilled water. The hydraulic conductivity of the grout was measured. The effect of the high alkaline ashes on the acidic drainage is of particular interest. This series of experiments provided information so that the most favorable grout (low hydraulic conductivity and high alkalinity) could be selected for injection into acidic spoil material. Both standard combustion and fluidized bed ashes were tested. Grout mixtures include ashes, scrubber sludge, lime, bentonite and/or kaolinite. Permeabilities of the mixtures averaged approximately 1.OE-4 cm/sec. A second series of laboratory experiments consists of grouting large diameter drums of acidic spoil with the fly ash grouts. The drums have been constructed and filled with acidic spoil material. The ungrouted infiltration rates have been determined and the resulting effluents chemically analyzed

  7. Synthesis and characterization of zeolite from coal ashes modified by cationic surfactant; Sintese e caracterizacao de zeolita de cinzas de carvao modificada por surfactante cationico

    Energy Technology Data Exchange (ETDEWEB)

    Fungaro, D.A.; Borrely, S.I., E-mail: dfungaro@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2012-01-15

    Zeolite synthesized from coal fly ash was modified with different concentrations (2 and 20 mmol.L{sup -1}) of hexadecyltrimethylammonium bromide (HDTMA-Br). The Non-Modified Zeolite (NMZ) and Surfactant-Modified Zeolites (SMZ) were characterized by X-ray fluorescence spectrometry, X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy, thermogravimetric analysis, among others. The SMS presented negative charge probably due to the formation of a partial bilayer of HDTMA on exchangeable active sites on the external surface of NMZ. A decrease in surface area was observed for SMZ as compared to NMZ indicating zeolite surface coverage with HDTMA-Br molecules. The crystalline nature of the zeolite remained intact after adsorption of surfactant and heating for drying. FTIR analysis indicated that there were no significant changes in the structure of the zeolite after adsorption of surfactant. (author)

  8. Liver histopathology of the southern watersnake, Nerodia fasciata fasciata, following chronic exposure to trace element-contaminated prey from a coal ash disposal site

    Energy Technology Data Exchange (ETDEWEB)

    Ganser, L.R.; Hopkins, W.A.; O' Neil, L.; Hasse, S.; Roe, J.H.; Sever, D.M. [St Marys College, Notre Dame, IN (USA). Dept. of Biology

    2003-03-01

    Previous studies have demonstrated the accumulation of arsenic, cadmium, selenium, strontium, and vanadium in livers of Southern Watersnakes fed fish from a coal-ash contaminated site. Our study is the first to investigate effects of trace element accumulation on cytology of snake liver. Snakes were born in the laboratory and raised for one or two years on diets consisting of varying proportions of contaminated fish. The majority (71%) of snakes fed contaminated prey did not exhibit any differences in liver histology when compared to control snakes fed an uncontaminated diet. In the remaining contaminant-exposed snakes, some aberrations were noted. The most prevalent pathology involved the proliferation of collagen fibers that resulted in narrowing or occlusion of sinusoids and increasing the mass of the intersinsuoidal parenychma. Fibrosis of the liver as a result of chronic injury has been reported previously in reptiles, but this is the first report that links such tissue damage to dietary contamination.

  9. Study of the Analytical Conditions for the Determination of Cadmium in Coal Fly Ashes by GFAAS with evaluation of several matrix modifiers

    International Nuclear Information System (INIS)

    A new method for the determination of cadmium in coal fly ash samples by Graphite Furnace Atomic Absorption Spectrometry (GFAAS) has been developed. Analytical conditions and different instrumental parameters have been optimized. In a first step, several types of matrix modifiers have been tested and a mixture of 2% NH4H2PO4 with 0.4%Mg(NO3)2 in 0.5N HNO3 has been selected, since it provides the highest sensitivity. In a second step, an optimization of several conditions, using the selected modifier, has been carried out, such as ashing and atomization temperatures, heating rate, etc. The influence of the use of a L' vov platform on the analytical and background signals has been studied, showing a significative decrease on the background signal, being the net absorbance similar to those obtained in absence of the platform. Using the optimal conditions, the direct method with standard samples provides cadmium concentration consistent with those obtained using the standard addition method. (Author) 18 refs

  10. Leaching from biomass combustion ash

    DEFF Research Database (Denmark)

    Maresca, Alberto; Astrup, Thomas Fruergaard

    2014-01-01

    in water. The content of the selected heavy metals (i.e. Cr, Ni, Pb and Cd) complied with the Danish Statutory Order on the use of bio-ash for agricultural purposes; however, critical releases of Cr were detected in the leachate extracts, especially in the fly ash. High alkaline pHs were measured in all...

  11. Experimental Study on Gasification and Ash Fusion Characteristics of Coal with High Ash Fusion Temperatures%高灰熔点煤气化特性及灰渣熔融特性的研究

    Institute of Scientific and Technical Information of China (English)

    乌晓江; 张忠孝; 徐雪元; 刘建斌; 张建文

    2011-01-01

    在0.1-0.2 kg/h小型电加热式常压气流床气化装置上,研究了不同温度、不同O/C物质的量比对高灰熔点煤气化特性和煤灰熔融特性的影响.结果表明:在不同温度下,随着O/C物质的量比增加,CO2体积分数呈线性增加.当O/C物质的量比较低时,H2和CH4体积分数较高;随着O/C物质的量比的增加,合成气中H2和CH4的含量下降较快.在不同温度下,随着O/C物质的量比的增加,碳转化率增加;但当O/C物质的量比达到1.1时,进一步增大O/C物质的量比,则使得炉内煤焦及合成气中可燃气体(CO、H2、CH4等)的燃烧%The effect of temperature and O/C molar ratio on coal gasification and ash fusion characteristics was studied in a 0.1~0.2 kg/h lab-scale electrical entrained-bed coal gasification setup.Results show that the yield of CO2 in syngas increases linearly with rising O/C molar ratio at different temperatures.When O/C molar ratio is at relatively low value,the yields of H2 and CH4 are relatively high,but the yields drop rapidly later on with increasing O/C molar ratio.The carbon conversion increases with growing O/C molar ratio at different temperatures.However,when the O/C molar ratio arrives at 1.1,with further increase of O/C molar ratio,more CO2 and H2O as well as less CO and H2 will be produced due to the increasing combustion share of combustible gases in char and syngas,such as CO,H2 and CH4,which subsequently lead to lower cold gas efficiency.Based on above test conditions,the optimum O/C molar ratio window is found to be 0.9-1.1 while the optimum temperature window is 1 300-1 350 ℃ for Huainan high ash fusion temperature coal with dry ash handling system.

  12. Chronic Ingestion of Coal Fly-Ash Contaminated Prey and Its Effects on Health and Immune Parameters in Juvenile American Alligators (Alligator mississippiensis).

    Science.gov (United States)

    Finger, John W; Hamilton, Matthew T; Metts, Brian S; Glenn, Travis C; Tuberville, Tracey D

    2016-10-01

    Coal-burning power plants supply approximately 37 % of the electricity in the United States. However, incomplete combustion produces ash wastes enriched with toxic trace elements that have historically been disposed of in aquatic basins. Organisms inhabiting such habitats may accumulate these trace elements; however, studies investigating the effects on biota have been primarily restricted to shorter-lived, lower-trophic organisms. The American alligator (Alligator mississippiensis), a long-lived, top-trophic carnivore, has been observed inhabiting these basins, yet the health or immune effects of chronic exposure and possible accumulation remains unknown. In this study, we investigated how chronic dietary ingestion of prey contaminated with coal combustion wastes (CCWs) for 25 months, and subsequent accumulation of trace elements present in CCWs, affected juvenile alligator immune function and health. Alligators were assigned to one of four dietary-treatment groups including controls and those fed prey contaminated with CCWs for one, two, or three times a week. However, no effect of Dietary Treatment (p > 0.05) was observed on any immune parameter or hematological or plasma analyte we tested. Our results suggest that neither exposure to nor accumulation of low doses of CCWs had a negative effect on certain aspects of the immune and hematological system. However, future studies are required to elucidate this further. PMID:27475646

  13. Effect of temperature on the hydration process and strength development in blends of Portland cement and activated coal gangue or fly ash

    Institute of Scientific and Technical Information of China (English)

    Pei-ming WANG; Xian-ping LIU

    2011-01-01

    This paper describes the results of an investigation into the effect of the variation of curing temperatures between 0 and 60 ℃ on the hydration process,pore structure variation,and compressive strength development of activated coal gangue-cement blend (ACGC).Hardened ACGC pastes cured for hydration periods from 1 to 360 d were examined using the non-evaporable water method,thermal analysis,mercury intrusion porosimetry,and mechanical testing.To evaluate the specific effect of activated coal gangue (ACG) as a supplementary cementing material (SCM),a fly ash-cement blend (FAC) was used as a control.Results show that raising the curing temperature accelerates pozzolanic reactions involving the SCMs,increasing the degree of hydration of the cement blends,and hence increasing the rate of improvement in strength.The effect of curing temperature on FAC is greater than that on ACGC.The pore structure of the hardened cement paste is improved by increasing the curing temperature up to 40 ℃,but when the curing temperature reaches 60 ℃,the changing nature of the pore structure leads to a decrease in strength.The correlation between compressive strength and the degree of hydration and porosity is linear in nature.

  14. Interrelations of catalytic index of coal ash component%煤中灰成分催化指数的相关性

    Institute of Scientific and Technical Information of China (English)

    梁建华; 史世庄; 张康华; 彭靖; 雷耀辉; 吴琼

    2011-01-01

    According to summarizing different methods of defining catalytic index of ash component of coking coal at home and abroad, do experiments with ten kinds of blended coals, discuss the correlation among the various definitions of catalytic index. The results show that there is a good correlation among MBI, MCI, MMCI, MCIy. The correlation coefficient between MBI and MCI is 0. 9905, MCIy and MBI is 0. 9821, MCIy and MCI is 0.9986. To a certain degree, these four methods are interchangeable.%总结国内外不同方法的煤中灰成分催化指数定义的基础上,对10种配合煤进行了试验,探讨了不同方法的催化指数之间的相关性.结果表明,MBI,MCI,MMCI,MCIy四者之间的相关性良好,MBI和MCI之间相关性系数为0.9905,MCL和MBI之间相关性系数为0.9821,MCIy和MCI之间相关性系数为0.9986.在一定程度上,四者可以互换.

  15. Determination of technologically enhanced naturally occurring radioactive material (TENORM) in ashes from coal-fired thermal power plants in the Philippines

    International Nuclear Information System (INIS)

    The activity concentration (AC) of TENORM - 238U, 226Ra (238U series), 232Th, 228Ra, 228Th (232Th series) and 40K in feed coal, bottom ash and fly ash samples from four coal-fired thermal power plants C, M, P and S were determined using two techniques: inductively coupled plasma mass spectrometry (ICP-MS) and high purity germanium (HPGe) gamma spectrometry. For 232Th and 238U [determined at National Institute for Radiological Sciences (NIRS) by the ICP-MS)], Plant S feed coal (FC) sample that originated from China had the highest AC (15.77 ± 0.32 Bq/kg and 13.67 ± 0.82 Bq/kg, respectively), followed by Plant M FC sample also from China (8.31 ± 0.33 Bq/kg and 5.84 ± 0.12 Bq/kg, respectively), while Plants C and P FC samples that originated from the Philippines and Indonesia had the lowest ACs of 232Th and 238U. Plant S also had the highest bottom ash (BA) AC of 80.86 ± 3.23 Bq/kg and 100.20 ± 4.01 Bq/kg, respectively while Plant P had the highest fly ash (FA) AC of 155.96 ± 6.24 Bq/kg and 268.03 ± 10.72 Bq/kg, respectively. For AC's of 226Ra, 228Ra, 228Th and 40K determined by NIRS HPGe, Plant C had the highest in the FC sample (11.70 ± 1.39 Bq/kg, 13.65 ± 4.99 Bq/kg, 11.35 ± 3.96 Bq/kg ad 80.23 ± 10.91 Bq/kg, respectuvely). For AC's in the BA samples, Plant M had the highest 226Ra (106.73 ± 6.74 Bq/kg) and Plant S had the highest 228Ra and 40K (66.64 ± 8.16 Bq/kg and 400.93 ± 43.06 Bq/kg, respectively For AC's in the FA samples, Plant S had the highest 226Ra and228Ra AC's (131.13 ± 8.09 Bq/kg and 87.70 ± 10.45 Bq/kg, respectively) while Plant C had the highest 40K AC (369.08 ± 40.87 Bq/kg). The highest AC enhancement of 238U, 226Ra (238U series), 232Th,228Ra, 228Th (232Th series) 40K relative to feed coal occurred in Plant P FA sample, with 238U showing the highest enhancement of 93.72 among the radionuclides. When normalized with 40K, 238U in Plant P FA sample also had the highest enrichment factor (EF). Except for Plant C samples, 228Ra, 228Th

  16. Advanced development of a pressurized ash agglomerating fluidized-bed coal gasification system: Topical report, Process analysis, FY 1983

    Energy Technology Data Exchange (ETDEWEB)

    None

    1987-07-31

    KRW Energy Systems, Inc., is engaged in the continuing development of a pressurized, fluidized-bed gasification process at its Waltz Mill Site in Madison, Pennsylvania. The overall objective of the program is to demonstrate the viability of the KRW process for the environmentally-acceptable production of low- and medium-Btu fuel gas from a variety of fossilized carbonaceous feedstocks and industrial fuels. This report presents process analysis of the 24 ton-per-day Process Development Unit (PDU) operations and is a continuation of the process analysis work performed in 1980 and 1981. Included is work performed on PDU process data; gasification; char-ash separation; ash agglomeration; fines carryover, recycle, and consumption; deposit formation; materials; and environmental, health, and safety issues. 63 figs., 43 tabs.

  17. Trace element partitioning behavior of coal gangue-fired CFB plant: experimental and equilibrium calculation.

    Science.gov (United States)

    Zhang, Yingyi; Nakano, Jinichiro; Liu, Lili; Wang, Xidong; Zhang, Zuotai

    2015-10-01

    Energy recovery is a promising method for coal gangue utilization, during which the prevention of secondary pollution, especially toxic metal emission, is a significant issue in the development of coal gangue utilization. In the present study, investigation into trace element partitioning behavior from a coal gangue-fired power plant in Shanxi province, China, has been conducted. Besides the experimental analysis, thermodynamic equilibrium calculation was also conducted to help the further understanding on the effect of different parameters. Results showed that Hg, As, Be, and Cd were highly volatil