WorldWideScience

Sample records for alkaline coal ash

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

    International Nuclear Information System (INIS)

    Highlights: ► Incinerator fly ash (IFA) is added to an alkali activated coal fly ash (CFA) matrix. ► Means of stabilizing the incinerator ash for use in construction applications. ► Concrete made from IFA, CFA and IFA-CFA mixes was chemically characterized. ► Environmentally friendly solution to IFA disposal by reducing its toxicity levels. - Abstract: 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 5.00 mg/L, respectively.

  2. 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 5.00 mg/L, respectively. PMID:22542857

  3. Injection of alkaline ashes into underground coal mines for acid mine drainage abatement

    International Nuclear Information System (INIS)

    The injection of alkaline coal combustion waste products into abandoned underground coal mines for acid mine drainage (AMD) abatement has obvious conceptual appeal. This paper summarizes the findings of the baseline hydrogeologic and water quality evaluations at two sites--one in West Virginia and one in Maryland--where field demonstrations of the technique are being pursued in cooperative efforts among State and Federal agencies and/or private companies. The West Virginia site produces severe AMD from three to seven AMD sources that are spaced over about a 1.2 km stretch of the down-dip side of the mine workings. By completely filling the most problematic portion of the mine workings with coal combustion ashes, the State expects that the costs and problems associated with AMD treatment will be greatly reduced. At the Maryland site, it is expected that the AMD from a relatively small target mine will be eliminated completely by filling the entire mine void with a grout composed of a mixture of fly ash, fluidized-bed combustion ash, and flue gas desulfurization sludge. This project will also demonstrate the potential cost-effectiveness of the technique at other sites, both for the purpose of AMD remediation and control of land subsidence

  4. Alkaline hydrothermal de-ashing and desulfurization of low quality coal and its application to hydrogen-rich gas generation

    International Nuclear Information System (INIS)

    This paper describes experimental research and a fundamental study of alkaline hydrothermal treatment of high-sulfur, high-ash coal from Banten, Java-Indonesia. Experiments were carried out on a laboratory-scale 0.5 L batch reactor. The alkaline hydrothermal treatment gave upgraded clean coal with low sulfur content (about 0.3 wt.%) and low ash content (about 2.1 wt.%). A zero carbon dioxide and pure hydrogen gas were produced at 330 oC by introducing an alkali (sodium hydroxide, NaOH) to the hydrothermal treatment of raw coal. X-ray diffraction (XRD) and X-ray fluorescence (XRF) techniques were used to test for the removal or reduction of major inorganic elements in the coal, and changes in carbon-functional groups and their properties were determined by Fourier transform infrared spectroscopy (FTIR) and Carbon-13 of nuclear magnetic resonance (13C NMR) tests on the product of the hydrothermal upgrading and demineralization process.

  5. Alkaline hydrothermal de-ashing and desulfurization of low quality coal and its application to hydrogen-rich gas generation

    Energy Technology Data Exchange (ETDEWEB)

    Mursito, Anggoro Tri [Research Centre for Geotechnology, Indonesian Institute of Sciences (LIPI), Jl. Sangkuriang Komplek LIPI, Gd. 70, Bandung 40135 (Indonesia); Department of Earth Resources Engineering, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishiku, Fukuoka 819-0395 (Japan); Hirajima, Tsuyoshi; Sasaki, Keiko [Department of Earth Resources Engineering, Faculty of Engineering, Kyushu University, 744 Motooka, Nishiku, Fukuoka 819-0395 (Japan)

    2011-01-15

    This paper describes experimental research and a fundamental study of alkaline hydrothermal treatment of high-sulfur, high-ash coal from Banten, Java-Indonesia. Experiments were carried out on a laboratory-scale 0.5 L batch reactor. The alkaline hydrothermal treatment gave upgraded clean coal with low sulfur content (about 0.3 wt.%) and low ash content (about 2.1 wt.%). A zero carbon dioxide and pure hydrogen gas were produced at 330 C by introducing an alkali (sodium hydroxide, NaOH) to the hydrothermal treatment of raw coal. X-ray diffraction (XRD) and X-ray fluorescence (XRF) techniques were used to test for the removal or reduction of major inorganic elements in the coal, and changes in carbon-functional groups and their properties were determined by Fourier transform infrared spectroscopy (FTIR) and Carbon-13 of nuclear magnetic resonance ({sup 13}C NMR) tests on the product of the hydrothermal upgrading and demineralization process. (author)

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

    International Nuclear Information System (INIS)

    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 (∼12), were below regulatory limits of most EU countries. Arsenic concentrations in CCR transport water were -1 whereas reductive conditions in an abandoned landfill significantly enhanced concentrations in leachates (44 μg l-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. - Uncontrolled farming and tillage of previously soil-covered coal ash landfills resulted in exposure of ash on the surface

  7. Processes controlling the variations of pH, alkalinity, and CO2 partial pressure in the porewater of coal ash disposal site

    International Nuclear Information System (INIS)

    Alkalinity, pH, and pCO2 are generally regarded as the most important parameters affecting trace element leaching from coal ashes. However, little is known about how those parameters are actually regulated in the field condition. This study investigated the processes controlling those parameters by observing undisturbed porewater chemistry in a closed ash disposal site. The site is now covered with 30-50 cm thick soils according to the management scheme suggested by the Waste Management Law of Korea and our results show the important role of soil cover regulating those parameters in the shallow porewater. Without the soil cover, the shallow porewater shows low pCO2 and alkalinity, and highly alkaline pH. In contrast, the porewater shows much higher alkalinity and near neutral pH range when the site was covered with the low permeability soils. This difference was caused by the CO2 supply condition changes associated with the changes in infiltration rate. The geochemical modeling shows that the calcite precipitations induced by porewater aging, dolomitization, and weathering of solid phases are the main processes controlling alkalinity, pH, and pCO2 in the deep saline porewaters. The weathering of coal ash plays the most important role decreasing the alkalinity in the deep porewater.

  8. 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. PMID:25004853

  9. 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.

  10. Coal ash utilisation in India

    International Nuclear Information System (INIS)

    Coal based thermal power stations have been the major source of power generation in our country in the past and would continue for decades to come. In India, thermal generation which contributes about 72% of the overall power generation of 2,45,000 MU (1989-90) is the main source of power and mainly based on coal firing. Total ash generation in India presently is to the tune of 38 million tonnes per annum. India is fourth in the world as far as coal ash generation is concerned. USSR is first, (100 million tonnes), then come USA (45 million tonnes) and China (41 million tonnes). The basic problem of thermal power station fired with high ash content coal is the generation of huge quantity of coal ash which would pose serious environmental and other related problems. The present paper analyses the extensive scope of utilisation of coal ash and enlightens the strategies to be adopted to overcome the related problems for proper utilisation of coal ash. (author). 9 tabs

  11. 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...

  12. Classification of pulverized coal ash

    International Nuclear Information System (INIS)

    The leachability of fifty different pulverized coal ashes from utilities in the Netherlands, Federal Republic of Germany and Belgium has been studied. Five different ashes were analyzed according to the complete standard leaching test and the results were published earlier. The examination of a wide variety of ashes under a wide range of pH and Liquid to Solid ratio (LS) conditions creates the possibility of identifying systematic trends in fly ash leaching behaviour and to identify the mechanisms controlling release. 16 figs., 2 tabs., 3 app., 25 refs

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

    International Nuclear Information System (INIS)

    Aiming at the development of a phosphorus removal technology for waste water, phosphate (PO43-) 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 Ca2+ and PO43- 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 (Ca3(PO4)2) and hydroxyapatite (Ca5(PO4)3OH), 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

  14. 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.

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

    Science.gov (United States)

    Yan, Jinying; Kirk, Donald W; Jia, Charles Q; Liu, Xinan

    2007-09-01

    Aiming at the development of a phosphorus removal technology for waste water, phosphate (PO(4)(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 (4000-30,000mgP/kg) than bottom ashes (15-600mgP/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(2+) and PO(4)(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(3)(PO(4))(2)) and hydroxyapatite (Ca(5)(PO(4))(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. PMID:17400372

  16. Coal ash artificial reef demonstration

    International Nuclear Information System (INIS)

    This experimental project evaluated the use of coal ash to construct artificial reefs. An artificial reef consisting of approximately 33 tons of cement-stabilized coal ash blocks was constructed in approximately 20 feet of water in the Gulf of Mexico approximately 9.3 miles west of Cedar Key, Florida. The project objectives were: (1) demonstrate that a durable coal ash/cement block can be manufactured by commercial block-making machines for use in artificial reefs, and (2) evaluate the possibility that a physically stable and environmentally acceptable coal ash/cement block reef can be constructed as a means of expanding recreational and commercial fisheries. The reef was constructed in February 1988 and biological surveys were made at monthly intervals from May 1988 to April 1989. The project provided information regarding: Development of an optimum design mix, block production and reef construction, chemical composition of block leachate, biological colonization of the reef, potential concentration of metals in the food web associated with the reef, acute bioassays (96-hour LC50). The Cedar Key reef was found to be a habitat that was associated with a relatively rich assemblage of plants and animals. The reef did not appear to be a major source of heavy metals to species at various levels of biological organization. GAI Consultants, Inc (GAI) of Monroeville, Pennsylvania was the prime consultant for the project. The biological monitoring surveys and evaluations were performed by Environmental Planning and Analysis, Inc. of Tallahassee, Florida. The chemical analyses of biological organisms and bioassay elutriates were performed by Savannah Laboratories of Tallahassee, Florida. Florida Power Corporation of St. Petersburg, Florida sponsored the project and supplied ash from their Crystal River Energy Complex

  17. INAA multielemental analysis of Nigerian bituminous coal and coal ash

    International Nuclear Information System (INIS)

    Instrumental neutron activation analysis (INAA) was used to analyze Nigerian bituminous coal and ash. Good statistical agreement (p≤0.05) between the literature and reported elemental values of USGS AGV-1 sample was found. Many elements were determined in the coal with some enrichment in the coal ash. Arsenic was measured only in the ash while Hg was present only in the coal. Coal ashing at 800 deg C contributed to a loss of Hg in the ash. Al, Na, Mg, Ti, Fe, which are major elements were found in the coal as expected, with slight enrichment in the ash. Ca and Si were only obtained in the ash. High ash Al (14.9±0.19%) and Si (25.3±4.11%) levels are of concern due to possible cases of pneumoconiosis from inhalation of the particulates. Graphical illustration of the lanthanide concentrations peaked at Ce with a decrease from Sm to Lu. U and Th were also present in the samples showing slight enhancement in the ash. Comparatively low coal elemental values, notably S(1.8%), highly advocate this coal as a good quality fuel-coal. (author) 16 refs.; 1 fig.; 2 tabs

  18. Adding coal ash to the composting mixes

    Energy Technology Data Exchange (ETDEWEB)

    Beaver, T. [Washington State University, Pullman, WA (United States). Center for Sustaining Agriculture and Natural Resources

    1995-03-01

    Coal ash will be one of the feed-stocks used in a Washington State University program to compost 16,500 tons of material generated annually on the Pullman campus. The university`s power plant generates approximately 1,000 tons of coal ash each year during fall and winter when coal is used as a backup to natural gas. Based on results of a pilot study begun in March, 1993, the ash will be mixed with 10,000 tons of manure and 440 tons of pulped food waste from dining halls. Mixed waste paper and landscape trimmings also will be composted. The pilot study used compost and separated cow manure to determine if composting coal ash would ameliorate storage and application problems. The objectives of the study were to determine the amount of coal ash that could be added to compost piles without compromising biological activity; to monitor the chemical composition of compost with additions of coal ash; and to quantify barley grain yields using coal ash compost. 5 refs., 1 fig., 2 tabs.

  19. Dissolution of lime into coal ash slags

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, L.; Wall, T.; Wang, S.M. [Newcastle Univ., Callaghan (Australia)

    1996-10-01

    One of the alternate processes presently being investigated to produce electrical power from coal is Integrated Gasification Combined Cycle (IGCC). The ash that remains when the coal is gasified in this process is removed by granulating the molten ash at 1400-1500{degrees}C. To reduce the melting temperature of the coal ash, a flux, usually limestone, is added with the coal to the gasifier. This paper reports the investigation of the rate of lime dissolution into synthetic coal ashes, consisting of SiO{sub 2}, Al{sub 2}O{sub 3} and CaO (SiO{sub 2}/Al{sub 2}O{sub 3} = 2 to 3.35). Preliminary measurements indicated that the dissolution of fix particles (50-200 {mu}m) is mass transfer controlled. A high temperature viscometer was used to rotate a cylinder of lime in the molten slag for a given period.

  20. 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

  1. COMPARISON OF LEACHABLE TRACE ELEMENT LEVELS IN COAL GASIFIER ASH WITH LEVELS IN POWER PLANT ASH

    Science.gov (United States)

    The paper gives results of a comparison of the levels of 14 trace elements in leachates from three types of ash of a common origin coal. The 1-year study was conducted at the Kosovo plant in Obilic, Yugoslavia, comparing coal gasifier ash with fly ash and bottom ash from a coal-f...

  2. Acid mine drainage mitigation using bulk blended fly ash/coal refuse mixtures: Column study results

    International Nuclear Information System (INIS)

    Many Appalachian coal refuse materials contain significant amounts of pyritic-S and are likely to produce acid mine drainage (AMD). A column technique was designed and implemented to evaluate the effects of various AMD mitigation treatments including fly ash, topsoil, lime, and rock-P. Two types of fly ash were tested, one at four rates of application, the other at two rates. Conventional lime plus topsoil, lime without topsoil, topsoil only, topsoil with fly ash, rock-P, rock-P plus topsoil, and rock-P plus fly ash were also evaluated and compared with pure refuse controls. The drainage from the unamended columns rapidly dropped to pH 2 with very high levels of Fe and Mn. Alkaline fly ash dramatically reduced drainage Fe concentrations as well as Mn when compared with untreated refuse. The rock-P treatment also improved drainage but eventually lost its mitigation capability. Leachate B concentrations were initially high for some of the ash columns, but decreased over time, while the unamended refuse B levels increased with time. Combined treatments of phosphate/ash, ash/topsoil, and pure refuse with topsoil were intermediate between the alkaline ash/lime treatments and unamended refuse in drainage quality. With further analysis, fly ash may prove to be a viable alternative to conventional topsoiling/lime treatments to control AMD if adequate alkalinity is present in the ash/refuse mixture. If fly ash alkalinity is inadequate to balance potential acidity, accelerated leaching of ash bound metals may occur. Therefore, the uncontrolled disposal of fly ash within coal refuse disposal facilities should be discouraged unless acid/base balance concerns are met

  3. CHARACTERIZATION OF ASH FROM COAL-FIRED POWER PLANTS

    Science.gov (United States)

    The report summarizes existing data on the chemical and physical characteristics of ashes produced by the burning of coal in steam-electric generating plants. It summarizes several recent coal or ash characterization studies, emphasizing the elemental chemical composition, partic...

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

    Science.gov (United States)

    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.

  5. 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 <1% of the total concentrations. Log-log plots of concentration and cumulative release of Fe versus time based on tank leaching data showed that leaching was dominated by diffusion. Overall, the risk of Zn, Pb, Mn, Cu and Fe leaching from coal ash and its 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. PMID:26764133

  6. Acid leaching of coal and coal-ashes

    Energy Technology Data Exchange (ETDEWEB)

    Meryem Seferinoglu; Mehtap Paul; Aake Sandstroem; Agah Koaker; Selami Toprak; Jan Paul [Lulea University of Technology, Lulea (Sweden). Division of Physics

    2003-10-01

    Twelve Turkish lignites and the corresponding ashes were leached in sulfuric acid (pH 1.0, 25{sup o}C) for 14 days. Leaching of dominant inorganic phases consume acid, but our interest is merely to remove trace elements present as dopants. We removed large fractions of Mg and Mn, but Al, K and Na extractions were limited by the presence of stable minerals and bimetallic oxides. The formation of the latter is driven by combustion at high temperatures. Alumina, normally not stable at pH 1.0, was protected from the effluent by the organic phase in coal. Fe leaching varied and appeared to be a marker for different chemical occurrences in the solids. Cd, V, Zn, U and Th were leached to near 80% from the ashes, but considerably less from the coals. Co and Ni extractions were near 60%, but not always higher from the ashes compared with the coals. Cu yields increase following ashing and reached ca. 60%. Ti, Ba, and Cs were not leached. We suggest that direct acid leaching is of interest to limit the deleterious impact of ash deposits and to recirculate metals from the ash. Ash may partly replace limestone in hydrometallurgical processing, but, more importantly, metal ions extracted from ash may be fed into the metal recovery stages of such processes. It is particularly interesting to leach Co, Cu, Ni and Zn, besides Mn, V and the environmentally hazardous Cd, U and Th. Leaching of whole coals is well motivated for domestic use-lump sizes around 18 50 mm, or slightly smaller, 10 mm, if mandated by practical residence times where generally no other measures are taken to protect the local environment. 79 refs., 4 figs., 6 tabs.

  7. Characterization of sintered coal fly ashes

    Energy Technology Data Exchange (ETDEWEB)

    M. Erol; S. Kucukbayrak; A. Ersoy-Mericboyu [Istanbul Technical University, Istanbul (Turkey). Department of Chemical Engineering, Chemical and Metallurgical Engineering Faculty

    2008-06-15

    Can, Catalagzi, Seyitomer and Afsin-Elbistan thermal power plant fly ashes were used to investigate the sintering behavior of fly ashes. For this purpose, coal fly ash samples were sintered to form ceramic materials without the addition of any inorganic additives or organic binders. In sample preparation, 1.5 g of fly ash was mixed in a mortar with water. Fly ash samples were uniaxially pressed at 40 MPa to achieve a reasonable strength. The powder compacts were sintered in air. X-ray diffraction analysis revealed that quartz (SiO{sub 2}), mullite (Al{sub 6}Si{sub 2}O{sub 13}), anorthite (CaAl{sub 2}Si{sub 2}O{sub 8}), gehlenite (Ca{sub 2}Al{sub 2}SiO{sub 7}) and wollastonite (CaSiO{sub 3}) phases occurred in the sintered samples. Scanning electron microscopy investigations were conducted on the sintered coal fly ash samples to investigate the microstructural evolution of the samples. Different crystalline structures were observed in the sintered samples. The sintered samples were obtained having high density, low water adsorption and porosity values. Higher Al{sub 2}O{sub 3} + SiO{sub 2} contents caused to better properties in the sintered materials. 19 refs., 5 figs., 4 tabs.

  8. 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.

  9. Solubility and transport of arsenic coal ash

    International Nuclear Information System (INIS)

    An experimental method combined with a numerical model allows a comparison of two methods for the disposal of ash that contains arsenic, from the Rio Escondido coal-fired power plant. The calculation yields significant differences in aquifer migration times for the site. The wet disposal method gave 10 years time and the dry method gave 22 years. Experiments were performed on the rate of dissolution of the arsenic from ash samples; and these results indicate a first order kinetics reaction. 8 refs., 8 figs., 8 tabs

  10. Effects of pulverized coal fly-ash addition as a wet-end filler in papermaking

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, A.S.K. [SLIET, Longowal (India). Dept. of Chemical Technology

    2008-09-15

    This experimental study is based on the innovative idea of using pulverized coal fly ash as a wet-end filler in papermaking. This is the first evaluation of the possible use of fly ash in the paper industry. Coal-based thermal power plants throughout the world are generating fly ash as a solid waste product. The constituents of fly ash can be used effectively in papermaking. Fly ash has a wide variation in particle size, which ranges from a few micrometers to one hundred micrometers. Fly ash acts as an inert material in acidic, neutral, and alkaline papermaking processes. Its physical properties such as bulk density (800-980 kg/m{sup 3}), porosity (45%-57%), and surface area (0.138-2.3076 m{sup 2}/g) make it suitable for use as a paper filler. Fly ash obtained from thermal power plants using pulverized coal was fractionated by a vibratory-sieve stack. The fine fraction with a particle size below 38 micrometers was used to study its effect on the important mechanical-strength and optical properties of paper. The effects of fly-ash addition on these properties were compared with those of kaolin clay. Paper opacity was found to be much higher with fly ash as a filler, whereas brightness decreased as the filler percentage increased Mechanical strength properties of the paper samples with fly ash as filler were superior to those with kaolin clay.

  11. 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.

  12. 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)

  13. Studies on the phase mineralogy and leaching characteristics of coal fly ash

    International Nuclear Information System (INIS)

    The phase mineralogy and leaching characteristics of some Indian coal fly ashes were studied to assess their safe disposal in abandoned coal mines. Since, fly ash contains a number of toxic trace elements, the leaching of fly ash was tested using strong acid/alkali solutions and distilled water under different conditions (solid-liquid ratio, leaching time, pH) in the temperature range of 30-100 degree C. It was found that the concentration of various metals in leachates depends on their chemical nature, association with mineral phases of ash and follows the almost similar concentration profile to that of iron, especially in acidic medium. The distribution of toxic trace elements in fly ash and their leachability were found to depend on the amount of unburnt carbon and iron in fly ash. In alkaline medium, leaching of iron and toxic trace elements (except As) from fly ash was very negligible. Hence, alkali treatment of coal fly ash is desirable for its safe use in refilling of coal mines. 27 refs., 14 figs., 8 tabs

  14. Ash transformation during co-firing coal and straw

    DEFF Research Database (Denmark)

    Zheng, Yuanjing; Jensen, Peter Arendt; Jensen, Anker Degn; Sander, Bo; Junker, Helle

    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...... quality on fly ash and deposit properties, straw was co-fired with three kinds of coal in an entrained flow reactor. The compositions of the produced ashes were compared to the available literature data to find suitable scaling parameters that can be used to predict the composition of ash from straw and...... coal co-firing. Reasonable agreement in fly ash compositions regarding total K and fraction of water soluble K was obtained between co-firing in an entrained flow reactor and full-scale plants. Capture of potassium and subsequent release of HCl can be achieved by sulphation with SO2 and more...

  15. Physical and biological studies of coal and oil fly ash.

    OpenAIRE

    Fisher, G L; McNeill, K L; Prentice, B A; McFarland, A R

    1983-01-01

    Studies were performed to compare the physical and chemical characteristics and the in vitro macrophage cytotoxicity of oil and coal fly ash. Sampling methodology was developed to collect size-fractionated particulate matter from the smokestack of either a coal-fired or an oil-fired power plant. Morphological studies demonstrated particle heterogeneity, although most coal fly ash particles appeared to be spherical. Oil fly ash contained two major morphologies; nonopaque amorphous particles an...

  16. Geochemistry of coals, coal ashes and combustion wastes from coal-fired power stations

    International Nuclear Information System (INIS)

    Contents, concentration trends, and modes of occurrence of 67 elements in coals, coal ashes, and combustion wastes at eleven Bulgarian thermoelectric power stations (TPS) were studied. A number of trace elements in coal and coal ash have concentrations greater than their respective worldwide average contents (Clarke values). Trace elements are concentrated mainly in the heavy accessory minerals and organic matter in coal. In decreasing order of significance, the trace elements in coal may occur as: element-organic compounds; impurities in the mineral matter; major components in the mineral matter; major and impurity components in the inorganic amorphous matter; and elements in the fluid constituent. A number of trace elements in the waste products, similar to coal ashes, exceed known Clarke contents. Trace elements are mainly enriched in non-magnetic, heavy and fine-grained fractions of fly ash. They are commonly present as impurities in the glass phases, and are included in the crystalline components. Their accessory crystalline phases, element-organic compounds, liquid and gas forms, are of subordinate importance. Some elements from the chalcophile, lithophile and siderophile groups may release into the atmosphere during coal burning. For others, the combustion process appears to be a powerful factor causing their relative enrichment in the fly ash and rarely in the bottom ash and slag. 65 refs., 1 fig., 11 tabs

  17. Evaluation of engineering properties for the use of leached brown coal ash in soil covers.

    Science.gov (United States)

    Mudd, Gavin M; Chakrabarti, Srijib; Kodikara, Jayantha

    2007-01-31

    The need to engineer cover systems for the successful rehabilitation or remediation of a wide variety of solid wastes is increasing. Some common applications include landfills, hazardous waste repositories, or mine tailings dams and waste rock/overburden dumps. The brown coal industry of the Latrobe Valley region of Victoria, Australia, produces significant quantities of coal ash and overburden annually. There are some site-specific acid mine drainage (AMD) issues associated with overburden material. This needs to be addressed both during the operational phase of a project and during rehabilitation. An innovative approach was taken to investigate the potential to use leached brown coal ash in engineered soil covers on this overburden dump. The basis for this is two-fold: first, the ash has favourable physical characteristics for use in cover systems (such as high storage capacity/porosity, moderately low permeability, and an ability to act as a capillary break layer generating minimal leachate or seepage); and second, the leachate from the ash is mildly alkaline (which can help to mitigate and reduce the risk of AMD). This paper will review the engineering issues involved in using leached brown coal ash in designing soil covers for potentially acid-forming overburden dumps. It presents the results of laboratory work investigating the technical feasibility of using leached brown coal ash in engineered solid waste cover systems. PMID:16621267

  18. Metal removal from coal ashes and wastes

    Energy Technology Data Exchange (ETDEWEB)

    Canon, R.M.; Kelmers, A.D.; McDowell, W.J.; Seeley, F.G.; Watson, J.S.

    1979-01-01

    Laboratory-scale tests and preliminary engineering economic analyses have been performed to evaluate several processes for the recovery of aluminum and other metals from fly ash. Preliminary tests have also been made on two coal conversion ashes. The processes examined include: direct acid leach, lime-sinter, lime-soda sinter, and two new sinter-leach processes (calsinter and salt-soda sinter). The Calsinter process involves sintering with limestone and gypsum or flue gas desulfurization sludge at 1000 to 1200/sup 0/C, followed by sulfuric acid leaching. Each of the new sinter-leach processes recovers more than 95% of the aluminum along with substantial percentages of the other metals present. The recovered metals can be converted to a number of potentially saleable products.

  19. Norm in coal, fly ash and cement

    Energy Technology Data Exchange (ETDEWEB)

    Kant, K. [K.L.Mehta Dayanand College for Women, Dept. of Physics, Faridabad (India); Upadhyay, S.B. [B.S.A. College, Dept. of Physics, Mathura - 281 001 (U.P.), Mathura (India); Sharma, G.S. [B.S.A. College, Mathura - 281 001 (U.P.), Dept. of Physics, Mathura (India)

    2006-07-01

    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. {sup 222}Rn (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/m{sup 3} to 443 Bq/m{sup 3}, the radium concentration varied from 1.5 to 4.5 Bq/kg and radon exhalation rate varied from 11.8 mBq.kg{sup -1}.h{sup -1} to 35.7 mBq.kg{sup -1}.h{sup -1} for mass exhalation rate and from 104.5 mBq.m{sup -2}.h{sup -1} to 314.8 mBq.m{sup -2}.h{sup -1} for surface exhalation rate in coal samples. The radon concentration varied from 214 Bq/m{sup 3} to 590 Bq/m{sup 3}, the radium concentration varied from 1.0 to 2.7 Bq/kg and radon exhalation rate varied from 7.8 mBq.kg{sup -1}.h{sup -1} to 21.6 mBq.kg{sup -1}.h{sup -1} for mass exhalation rate and from 138 mBq m{sup -2}h{sup -1} to 380.6 mBq.m{sup -2}.h{sup -1} for surface exhalation rate in fly ash samples. The radon concentration varied from 157.62 Bq/m{sup 3} to 1810.48 Bq/m{sup 3}, the radium concentration varied from 0.76 Bq/kg to 8.73 Bq/kg and radon exhalation rate varied from 6.07 mBq.kg{sup -1}.hr{sup -1} to 69.81 mBq.kg{sup -1}.hr{sup -1} for mass exhalation rate and from 107.10 mBq.m{sup -2}.hr{sup -1} to 1230.21 mBq.m{sup -2}.hr{sup -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)

  20. Mutagenicity of coal fly ash from electric power plant precipitators

    Energy Technology Data Exchange (ETDEWEB)

    Kubitschek, H.E.; Venta, L.

    1979-01-01

    The earlier work of Chrisp et al showed that stack-collected fly ash carried a low level of mutagenic activity, approximately 30 revertants per milligram. We find, in contrast, that fly ash collected from precipitators of the same kinds of electrical power plants, burning a similar type of coal, are not observably mutagenic in the same assay system. Our results indicate that although precipitator fly ash account for approximately 95% of the fly ash product, it contributes little if at all to the total mutagenic activity of fly ash produced by coal-fired power plants.

  1. Size distribution of rare earth elements in coal ash

    Science.gov (United States)

    Scott, Clinton T.; Deonarine, Amrika; Kolker, Allan; Adams, Monique; Holland, James F.

    2015-01-01

    Rare earth elements (REEs) are utilized in various applications that are vital to the automotive, petrochemical, medical, and information technology industries. As world demand for REEs increases, critical shortages are expected. Due to the retention of REEs during coal combustion, coal fly ash is increasingly considered a potential resource. Previous studies have demonstrated that coal fly ash is variably enriched in REEs relative to feed coal (e.g, Seredin and Dai, 2012) and that enrichment increases with decreasing size fractions (Blissett et al., 2014). In order to further explore the REE resource potential of coal ash, and determine the partitioning behavior of REE as a function of grain size, we studied whole coal and fly ash size-fractions collected from three U.S commercial-scale coal-fired generating stations burning Appalachian or Powder River Basin coal. Whole fly ash was separated into , 5 um, to 5 to 10 um and 10 to 100 um particle size fractions by mechanical shaking using trace-metal clean procedures. In these samples REE enrichments in whole fly ash ranges 5.6 to 18.5 times that of feedcoals. Partitioning results for size separates relative to whole coal and whole fly ash will also be reported. 

  2. 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.

  3. Metal mobilization under alkaline conditions in ash-covered tailings.

    Science.gov (United States)

    Lu, Jinmei; Alakangas, Lena; Wanhainen, Christina

    2014-06-15

    The aim of this study was to determine element mobilization and accumulation in mill tailings under alkaline conditions. The tailings were covered with 50 cm of fly ash, and above a sludge layer. The tailings were geochemically and mineralogically investigated. Sulfides, such as pyrrhotite, sphalerite and galena along with gangue minerals such as dolomite, calcite, micas, chlorite, epidote, Mn-pyroxene and rhodonite were identified in the unoxidized tailings. The dissolution of the fly ash layer resulted in a high pH (close to 12) in the underlying tailings. This, together with the presence of organic matter, increased the weathering of the tailings and mobilization of elements in the uppermost 47 cm of the tailings. All primary minerals were depleted, except quartz and feldspar which were covered by blurry secondary carbonates. Sulfide-associated elements such as Cd, Fe, Pb, S and Zn and silicate-associated elements such as Fe, Mg and Mn were released from the depletion zone and accumulated deeper down in the tailings where the pH decreased to circum-neutral. Sequential extraction suggests that Cd, Cu, Fe, Pb, S and Zn were retained deeper down in the tailings and were mainly associated with the sulfide phase. Calcium, Cr, K and Ni released from the ash layer were accumulated in the uppermost depletion zone of the tailings. PMID:24681363

  4. Modeling batch leaching behavior of arsenic and selenium from bituminous coal fly ashes.

    Science.gov (United States)

    Su, Tingzhi; Wang, Jianmin

    2011-11-01

    Correctly predicting the leaching potential of arsenic (As) and selenium (Se) is critical for assessing the environmental impact of coal fly ash. This study investigated the impacts of several key environmental factors, including pH, leaching time, and ash washing on the batch leaching behavior of As and Se from bituminous coal fly ashes. The experimental results demonstrated that As and Se leaching from fly ash increased beyond the minimal leaching pH ranges. Increasing leaching time increased As leaching but decreased Se leaching in the alkaline pH condition. A speciation-based adsorption model was used to quantify the batch leaching data, and determine the intrinsic leaching parameters including the total batch leachable mass and the adsorption constant of As or Se. The modeling approach was validated by correctly predicting the independent batch leaching data in a broad pH range and a different L/S condition. Experimental and modeling results also demonstrated that ash washing and ash aging (longer leaching time) did not change the adsorption constants of As and Se on the ash surface. However, ash washing could increase the availability of As and Se for leaching. PMID:21880348

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

    Science.gov (United States)

    Reyes Caballero, F.; Martínez Ovalle, S. A.; Moreno Gutiérrez, M.

    2015-06-01

    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.

  6. 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

  7. 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.

  8. Ultrafine ash aerosols from coal combustion: Characterization and health effects

    Energy Technology Data Exchange (ETDEWEB)

    William P. Linak; Jong-Ik Yoo; Shirley J. Wasson; Weiyan Zhu; Jost O.L. Wendt; Frank E. Huggins; Yuanzhi Chen; Naresh Shah; Gerald P. Huffman; M. Ian Gilmour [US Environmental Protection Agency, Research Triangle Park, NC (United States). National Risk Management Research Laboratory

    2007-07-01

    Ultrafine coal fly-ash particles withdiameters less than 0.5 {mu}m typically comprise less than 1% of the total fly-ash mass. This paper reports research focused on both characterization and health effects of primary ultrafine coal ash aerosols alone. Ultrafine, fine, and coarse ash particles were segregated and collected from a coal burned in a 20 kW laboratory combustor and two additional coals burned in an externally heated drop tube furnace. Extracted samples from both combustors were characterized by transmission electron microscopy (TEM), wavelength dispersive X-ray fluorescence(WD-XRF) spectroscopy, Moessbauer spectroscopy, and X-ray absorption fine structure (XAFS) spectroscopy. Pulmonary inflammation was characterized by albumin concentrations in mouse lung lavage fluid after instillation of collected particles in saline solutions and a single direct inhalation exposure. Results indicate that coal ultrafine ash sometimes contains significant amounts of carbon, probably soot originating from coal tar volatiles, depending on coal type and combustion device. Surprisingly, XAFS results revealed the presence of chromium and thiophenic sulfur in the ultrafine ash particles. The instillation results suggested potential lung injury, the severity of which could be correlated with the carbon (soot) content of the ultrafines. This increased toxicity is consistent with theories in which the presence of carbon mediates transition metal (i.e., Fe) complexes, as revealed in this work by TEM and XAFS spectroscopy, promoting reactive oxygenspecies, oxidation-reduction cycling, and oxidative stress. 24 refs., 7 figs.

  9. 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, due to excessive wastage, certain tube samples needed to be removed and replaced in order to ensure that Test Sections B and C would have a chance of remaining in the boiler for their intended exposure period. These suspect tube samples were replaced and the two remaining test sections were put back into service. The tube samples that were removed from Test Sections B and C were set aside for later analysis at the end of the planned exposure period. Test Sections B and C were again examined approximately six months later. At that time, measured wall thickness losses raised concerns about additional tube samples. These suspect samples were also removed, set aside for later analysis, and replaced. The test sections then went back into service until the end of the second exposure period, which was concluded in May 2003 when, due to evidence of excessive wastage, the valves were opened increasing cooling steam flow and thereby effectively stopping corrosion. In August 2003, Test Sections B and C were removed for closer examination. Section C had experienced about 42 months of service at the desired team temperature set point with 28.5 months at temperature at full temperature. Additional suspect samples were removed from Test Section B, then, it was re-installed into the boiler (at the location originally occupied by Section C), where it remained in service until the end of the program. Due to this removal history, the samples from Test Section B had a total service duration that varied from a minimum of 15.5 months (for samples that performed poorly) to 37 months for samples the survived for the full intended service exposure for Section B. The figure below shows a schematic of Test Section B and indicates the length of service exposure for different locations. This report provides the results of the evaluation of Test Section B, including the samples that remained in the Test Section for the full exposure period as well as those that were removed early. This report also is intended to compare and summarize the results for all three test sections. The analysis of Test Section B followed much the same protocol that was employed in the assessment of the other two test sections. The focus was on determining and documenting the relative corrosion rates of the candidate materials; however, additional investigations were undertaken to better understand the wastage mechanism, and to characterize how selected candidate materials performed either well, or poorly, in the severe coal ash corrosion environment in the convection pass of Niles Unit No.1. 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 in all three test sections. The body of this report compares these for all of the samples in the test section.

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

    OpenAIRE

    Charles Begyina Kodjo Nketsiah

    2015-01-01

    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 t...

  11. Device for the ash content determination in coal samples

    International Nuclear Information System (INIS)

    The invention is concerned with a device for the ash content determination of selected ash components in coal samples by means of the neutron activation analysis. It allows an activation of samples up to some hundred grams and a fast sample changing with an always sufficient shielding. The device can easily be moved and is independent of an accelerator

  12. Assessing the environmental impact of coal ash disposal

    International Nuclear Information System (INIS)

    Ash produced from the combustion of brown coal in Victoria's Latrobe Valley is currently slurried into ash disposal ponds for storage. Subsequent to a review of ash production rates at the Loy Yang Power Station, a number of options for ash pond management were considered. These included excavating the aged ash from the existing pond and then depositing them downstream of the pond or into a nearby overburden dump. Prior to the re-classifying of ash, analytical testing was generally conducted on a total concentration basis and did not consider the leachable fraction of various elements from the ash. The current study of ash leaching involved the collection and testing of ash in three states, aged ash, slurry ash, and fresh ash. The analysis confirms that the aged ash, deposited within the disposal pond for 6 to 12 months, has reached the steady state point and can be considered to have a low potential for adverse impact on the beneficial use of groundwater and surface waters when excavated from the pond and dumped at other locations. It should also be noted that batch tests, where the material is shaken overnight, represents a worst case scenario of leaching. Such vigorous mixing would not normally occur in the field and consequently the leachates produced in the field can be expected to have a lower salinity for a longer period of time. (author). 6 tabs., 10 refs

  13. Mineralogy and geochemistry of Greek and Chinese coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Nikolaos K. Koukouzas; Rongshu Zeng; Vassilis Perdikatsis; Wendong Xu; Emmanuel K. Kakaras [Institute for Solid Fuels Technology and Applications, Attica Technology Park, Athens (Greece). Centre for Research and Technology Hellas

    2006-11-15

    In this paper the mineralogy and geochemistry of Greek and Chinese coal fly ash are examined. Annual production of fly ash in China is around 160 Mt while in Greece lignite fly ash accounts around 10 Mt. Even though the mineralogical and chemical composition of the fly ashes coming from these two countries differs, there are common questions on the utilization of this material. The variation of the Greek fly ash chemical composition, from Ca-poor to Ca-rich fly ash, has resulted to applications such as dam construction, use in cement and possibly in concrete and road construction. The Chinese fly ash, which is rich in mullite, is broadly applied for brick making. 13 refs., 6 figs., 3 tabs.

  14. Chemical composition and some trace element contents in coals and coal ash from Tamnava-Zapadno Polje Coal Field, Serbia

    Energy Technology Data Exchange (ETDEWEB)

    Vukasinovic-Pesic, V.; Rajakovic, L.J. [University of Montenegro, Podgorica (Montenegro)

    2009-07-01

    The chemical compositions and trace element contents (Zn, Cu, Co, Cr, Ni, Pb, Cd, As, B, Hg, Sr, Se, Be, Ba, Mn, Th, V, U) in coal and coal ash samples from Tamnava-Zapadno Polje coal field in Serbia were studied. The coal from this field belongs to lignite. This high volatility coal has high moisture and low S contents, moderate ash yield, and high calorific value. The coal ash is abundant in alumosilicates. Many trace elements such as Ni > Cd > Cr > B > As > Cu > Co > Pb > V > Zn > Mn in the coal and Ni > Cr > As > B > Cu > Co = Pb > V > Zn > Mn in the coal ash are enriched in comparison with Clarke concentrations.

  15. Investigation of precipitator ash from two sub-bituminous coals

    International Nuclear Information System (INIS)

    Iron-57 Moessbauer spectra of the precipitator ash from two South Australian coals have allowed the identification of five iron containing phases, with extensive aluminium substitution for iron. Some effects of variation in the flame temperature were observed, but the analysis did not explain differences in the fouling characteristics of the coals. (orig.)

  16. Effects of colemanite waste, coal bottom ash, and fly ash on the properties of cement

    Energy Technology Data Exchange (ETDEWEB)

    Kula, I.; Olgun, A.; Erdogan, Y.; Sevinc, V. [Celal Bayar University, Manisa (Turkey)

    2001-03-01

    The physical and chemical properties of colemanite ore waste from concentrator, coal bottom ash, fly ash, cement+ash mixtures, cement+colemanite ore waste, and their effects on the mechanical properties of concrete were investigated. These materials with different proportion were substituted with Portland cement. Physical properties such as setting time, volume expansion, and compressive strength were determined and compared to reference mixture and Turkish standards (TS). The results showed that cement replacement materials had clear effects on the mechanical properties. The use of fly ash and bottom ash even at the concentration of 25% showed either comparable or better result compared to reference mixture. Although replacement of Portland cement by 9 wt.% of colemanite ore waste causes reduction in the compressive strength, the values obtained are within the limit of TS. As a result, colemanite ore waste, fly ash, and bottom ash may be used as cementitious materials.

  17. Growth and elemental accumulation by canola on soil amended with coal fly ash.

    Science.gov (United States)

    Yunusa, I A M; Manoharan, V; DeSilva, D L; Eamus, D; Murray, B R; Nissanka, S P

    2008-01-01

    To explore the agronomic potential of an Australian coal fly ash, we conducted two glasshouse experiments in which we measured chlorophyll fluorescence, CO2 assimilation (A), transpiration, stomatal conductance, biomass accumulation, seed yield, and elemental uptake for canola (Brassica napus) grown on soil amended with an alkaline fly ash. In Experiment 1, application of up to 25 Mg/ha of fly ash increased A and plant weight early in the season before flowering and seed yield by up to 21%. However, at larger rates of ash application A, plant growth, chlorophyll concentration, and yield were all reduced. Increases in early vigor and seed yield were associated with enhanced uptake of phosphorus (P) by the plants treated with fly ash. Fly ash application did not influence accumulation of B, Cu, Mo, or Zn in the stems at any stage of plant growth or in the seed at harvest, except Mo concentration, which was elevated in the seed. Accumulation of these elements was mostly in the leaves, where concentrations of Cu and Mo increased with any amount of ash applied while that of B occurred only with ash applied at 625 Mg/ha. In Experiment 2, fly ash applied at 500 Mg/ha and mixed into the whole 30 cm soil core was detrimental to growth and yield of canola, compared with restricting mixing to 5 or 15 cm depth. In contrast, application of ash at 250 Mg/ha with increasing depth of mixing increased A and seed yield. We concluded that fly ash applied at not more than 25 Mg/ha and mixed into the top 10 to 15 cm of soil is sufficient to obtain yield benefits. PMID:18453446

  18. Ash fusion temperatures and the transformations of coal ash particles to slag

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, S.K.; Wall, T.F.; Creelman, R.A.; Gupta, R.P. [University of Newcastle, Newcastle, NSW (Australia). CRC for Black Coal Utilisation

    1998-07-01

    A mechanistic study is detailed in which coal ash is heated with its shrinkage measured continuously up to a temperature of 1600{degree}C. The temperature corresponding to the rapid rate of shrinkage correspond to the formation of eutectics identified on phase diagrams. Samples were therefore heated to these temperatures, cooled rapidly and examined using a scanning electron microscope (SEM) to identify the associated chemical and physical changes. The progressive changes in the range of chemical composition (from SEM), the extent of undissolved ash particles and porosity were then quantified and related to homogenisation, viscosity and ash fusion mechanisms. Alternate ash fusion temperatures based on different levels of shrinkage have also been suggested to characterise the ash deposition tendency of the coals. 13 refs., 9 figs.

  19. Chemical speciation of vanadium in coal bottom Ash

    Energy Technology Data Exchange (ETDEWEB)

    Aydin, Firat; Aydin, Isil; Hamamci, Candan [Science Faculty, Chemistry Department, Dicle University, Diyarbakir (Turkey); Saydut, Abdurrahman [Engineering Faculty, Mining Engineering Department, Dicle University, Diyarbakir (Turkey); Gunduz, Beniz [Science Faculty, Chemistry Department, Selcuk University, Konya (Turkey)

    2012-04-15

    Chemical speciation of vanadium is important to understand the true nature of this element in the environment as well as its biochemical pathways. Sample pretreatment, preparation, and chemical speciation methods were applied for vanadium in coal bottom ash here. Two-stage microwave acid digestion was used to preparation of samples. Determination of vanadium was performed using inductively coupled plasma-optical emission spectrometry (ICP-OES). Speciation of vanadium was carried out using a seven-step sequential extraction procedure of the coal bottom ash each releasing species of vanadium: Water soluble, exchangeable, carbonate, reducible, oxidizable, sulfide, and residual fractions. Total vanadium concentration in the coal bottom ash is 701 mg kg{sup -1} d.w. The most abundant form of vanadium in coal bottom ash is residual fraction of vanadium (196 mg kg{sup -1} d.w.). Relative abundances of the remaining vanadium fractions in coal bottom ash are as follows: Reducible (176 mg kg{sup -1} d.w.) > sulfide (176 mg kg{sup -1} d.w.) > carbonate (85 mg kg{sup -1} d.w.) > oxidizable (50 mg kg{sup -1} d.w.) > water soluble (10.6 mg kg{sup -1} d.w.) > exchangeable (9.0 mg kg{sup -1} d.w.). (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Radioactivity of coal ash used in building materials

    International Nuclear Information System (INIS)

    In Germany every year about 18 million tonnes of combustion by-products are produced in coal-fired power stations. In 1996 these by-products were boiler slag (about 3 million tonnes), bottom ash (about 3 million tonnes) and above all fly ash (about 12 million tonnes). 7.5 million tonnes result from the burning of bituminous coal and 10.3 million tonnes from lignite. About 98 % of the bituminous coal ash is used in construction and mining industry. The majority of lignite ash is used for the filling and re cultivation of open pit mines, it is utilized either unmixed or mixed with FGD ( flue-gas desulfurization) gypsum and FGD water. The natural radioactivity of coal and also of the ash mainly results from many natural radionuclides in the decay series of uranium-radium, thorium and to an insignificant extent of uranium-actinium, as well as from potassium-40. Because of the age of coal, the activity concentrations of the different radionuclides are in a radioactive equilibrium. 'Therefore it is sufficient to consider the significant radionuclides for the radiation doses in each natural decay series, namely radium-226 and thorium-232 with their daughters radon-222 and radon-220 and also potassium-40. lie contribution of the radionuclides of the uranium-actinium series to the radiation dose can be neglected. (authors)

  1. Damage cost of the Dan River coal ash spill

    International Nuclear Information System (INIS)

    The recent coal ash spill on the Dan River in North Carolina, USA has caused several negative effects on the environment and the public. In this analysis, I report a monetized value for these effects after the first 6 months following the spill. The combined cost of ecological damage, recreational impacts, effects on human health and consumptive use, and esthetic value losses totals $295,485,000. Because the environmental impact and associated economic costs of riverine coal ash spills can be long-term, on the order of years or even decades, this 6-month assessment should be viewed as a short-term preview. The total cumulative damage cost from the Dan River coal ash spill could go much higher. - Highlights: • Six-month post-spill damage cost exceeded $295,000,000. • Components of cost include ecological, recreational, human health, property, and aesthetic values. • Attempts by the electric utility to “clean” the river left over 95% of coal ash behind. • Long-term impacts will likely drive the total damage cost much higher. - Damage costs of the Dan River coal ash spill are extensive and growing. The 6-month cost of that spill is valued at $295,485,000, and the long-term total cost is likely to rise substantially

  2. Assessment of the impact of radionuclides in coal ash

    International Nuclear Information System (INIS)

    An assessment of the potential environmental and health impacts of radionuclides in the coal fuel cycle is being conducted at Mound. This paper describes studies evaluating the potential for migration of radionuclides from ash disposal sites. Studies at a power plant burning western-US coal dealt with an assessment of potential radiation doses from coal ash ponds and leachate discharges of radionuclides from the ponds. Emanation of 222Rn from the ash is relatively low. The emanation of 222Rn from the ash pond (226Ra at 4.5pCi.g-1) is predicted to be about six times less than from soil (226Ra at 1pCi.g-1). Ash with 226Ra at 25pCi.g-1 would approximate emanation of 222Rn from soil. At 1000m from the centre of the ash pond area, 222Rn from the ash pond is predicted to be 1000 to 6000 times less than background (0.1 to 0.5pCi.ltr-1). Pathways exist for transport of radionuclides leached from ash into the aquifer beneath the holding ponds, but concentrations of radionuclides in water leaving the ponds are lower than concentrations in groundwater which is upgradient of the ponds. Leachability of the ash is quite low, on the order of 0.002% in one month, and flow of ash-sluicing water (3% of the volume of the ponds each day) has actually diluted normal background concentrations of radionuclides in the aquifer between the ponds and the adjacent river. (author)

  3. 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

  4. The ash deposition mechanism in boilers burning Zhundong coal with high contents of sodium and calcium: A study from ash evaporating to condensing

    International Nuclear Information System (INIS)

    The high contents of sodium and calcium in Zhundong coal induce severe slagging and ash deposition in boilers. In this study, the ash deposition mechanism was investigated based on the results obtained from a full-scale boiler (350 MW) burning Zhundong coal, and a fixed bed reactor used for ash evaporating-condensing. In the full-scale boiler, the condensing and depositing of sodium and calcium sulfates play an important role on ash depositing on convection heating surfaces. Sulfates start to significantly condense and deposit at the flue gas temperature of about 850 °C on the medium and high temperature reheater surfaces. Ash evaporating tests proved that, with the increasing in temperature from 400 °C to 1200 °C, the ash evaporating process is divided into three stages: 1) 400–800 °C, 80% of sodium, and 100% of chlorine are released; 2) 800–1000 °C, all the left sodium evaporates and sulfur starts to be released with the formation of partial aluminosilicates; 3) 1000–1200 °C, all the left sulfur is released through the decomposition of calcium sulfates and then calcium starts to evaporate, while silicon oxides disappear due to the formation of new complex silicates. Ash condensing tests further proved that, the sodium in Zhundong coal was released mainly in the forms of atom, oxide, and chloride, in which sodium chloride account for about 50%. When the evaporating temperature increased higher than 1000 °C, partial alkali and alkaline earth metals were released as gaseous sulfates, and afterward condense and deposit on the heating surfaces. At last, a temperature-dependent ash deposition mechanism in Zhundong coal combustion was proposed. - Highlights: • The ash deposition of coal with high Na/Ca content was studied in full-scale and lab-scale furnaces. • The deposition mechanism was demonstrated from ash evaporating to condensing. • Sulfate condensing at about 850 °C plays an important role in ash deposition of Zhundong coal. • A temperature-dependent ash deposition mechanism was presented

  5. 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)

  6. A seasonal assessment of the impact of coal fly ash disposal on the River Yamuna, Delhi. I. Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Walia, A.; Mehra, N.K. [University of Delhi, Delhi (India). Dept. of Zoology

    1998-04-01

    The impact of fly ash on the chemistry of the River Yamuna was studied. By-products from a 200 MW capacity Indraprasha thermal power station on the west bank of the River Yamuna, Delhi are largely from coal combustion (fly ash) and are disposed of as a slurry in off-site ash ponds. Many elements associated with fly ash are soluble and become available to the biota. A two-year survey was made of the seasonal variations in limnochemical features in the non-impacted and the impacted segments of the river receiving fly ash effluent and the ash treatment ponds. Conductivity, TDS, DO, hardness, sulphate and nitrate increased significantly in the receiving waters over background values. The reverse was noticed for free CO{sub 2}, alkalinity and phosphate. Changes in some other parameters were insignificant. Fly ash effluent from the ash ponds significantly increased the concentration of some elements, viz., Al, Sb, Bi, Cd, Co, Cr, Li, Mn, Mo, K, Si and Zn in river water. Generally, the highest concentration of most parameters were recorded in the ash ponds. This investigation was helpful in assessing the effect of wet ash disposal on the river limnology and understanding the solubility of various elements in the ash ponds. 50 refs., 6 figs., 1 tab.

  7. A seasonal assessment of the impact of coal fly ash disposal on the River Yamuna, Delhi. I. Chemistry

    International Nuclear Information System (INIS)

    The impact of fly ash on the chemistry of the River Yamuna was studied. By-products from a 200 MW capacity Indraprasha thermal power station on the west bank of the River Yamuna, Delhi are largely from coal combustion (fly ash) and are disposed of as a slurry in off-site ash ponds. Many elements associated with fly ash are soluble and become available to the biota. A two-year survey was made of the seasonal variations in limnochemical features in the non-impacted and the impacted segments of the river receiving fly ash effluent and the ash treatment ponds. Conductivity, TDS, DO, hardness, sulphate and nitrate increased significantly in the receiving waters over background values. The reverse was noticed for free CO2, alkalinity and phosphate. Changes in some other parameters were insignificant. Fly ash effluent from the ash ponds significantly increased the concentration of some elements, viz., Al, Sb, Bi, Cd, Co, Cr, Li, Mn, Mo, K, Si and Zn in river water. Generally, the highest concentration of most parameters were recorded in the ash ponds. This investigation was helpful in assessing the effect of wet ash disposal on the river limnology and understanding the solubility of various elements in the ash ponds. 50 refs., 6 figs., 1 tab

  8. Influence of Coal Blending on Ash Fusibility in Reducing Atmosphere

    Directory of Open Access Journals (Sweden)

    Mingke Shen

    2015-05-01

    Full Text Available Coal blending is an effective way to organize and control coal ash fusibility to meet different requirements of Coal-fired power plants. This study investigates three different eutectic processes and explains the mechanism of how coal blending affects ash fusibility. The blended ashes were prepared by hand-mixing two raw coal ashes at five blending ratios, G:D = 10:90 (G10D90, G:D= 20:80 (G20D80, G:D = 30:70 (G30D70, G:D = 40:60 (G40D60, and G:D = 50:50 (G50D50. The samples were heated at 900 °C, 1000 °C, 1100 °C, 1200 °C, and 1300 °C in reducing atmosphere. XRD and SEM/EDX were used to identify mineral transformations and eutectic processes. The eutectic processes were finally simulated with FactSage. Results show that the fusion temperatures of the blended ashes initially decrease and then increase with the blending ratio, a trend that is typical of eutectic melting. Eutectic phenomena are observed in D100, G10D90, and G30D70 in different degrees, which do not appear in G100 and G50D50 for the lack of eutectic reactants. The main eutectic reactants are gehlenite, magnetite, merwinite, and diopside. The FactSage simulation results show that the content discrepancy of merwinite and diopside in the ashes causes the inconsistent eutectic temperatures and eutectic degrees, in turn decrease the fusion temperature of the blended ash and then increase them with the blending ratio.

  9. Toxicity of and metals in coal combustion ash leachate

    International Nuclear Information System (INIS)

    Land disposal of coal combustion ash can have a potential impact on the ecosystem due to the leaching of metals with increasing acidity of precipitation. The effect of pH on the concentration of metals leached from coal combustion ash was studied and the toxicity of the leachate measured. Bottom coal combustion ash was leached with hydrochloric acid (HCl) or acetic acid (CH3COOH) at pH 4,5,6 or 7. The toxicity of the aqueous leachates and concentrations of the metals (arsenic, cadmium, chromium, copper, iron, lead, nickel, silver and zinc) therein were measured using Microtox (Vibrio fischeri-EC50%) and atomic absorption spectrophotometry, respectively. Toxicity and metal concentrations of the leachates were highest when ash was leached with HCl at pH 4. Toxicity and metal concentrations of ash leached with CH3COOH were significantly lower compared with ash leached with HCl. A high correlation was observed between the toxicity and the metal concentrations in both the acid leachates

  10. On-conveyor belt determination of ash in coal

    International Nuclear Information System (INIS)

    A laboratory feasibility study has been carried out on new and advanced neutron and gamma-ray analysis systems for the direct on-conveyor belt analysis of ash in coal without the need for sample by-lines. Such an analysis system could deliver the combined advantages of a direct on-conveyor configuration with new and accurate analysis techniques. An industry survey of 18 coal companies carried out in early 1996 indicated that accurate on-belt ash analysis is of the highest priority. Subsequent laboratory work has focussed on the investigation of methods with the potential for improving the accuracy of ash content measurement relative to existing on-belt ash analysers, the most widely-used of which are based on dual energy gamma-ray transmission (DUET), which is sensitive to variations in ash composition. The current work indicates that on-belt neutron/gamma-ray techniques combined with advanced spectral analysis techniques show promise for development into an on-belt ash analysis system which is significantly less sensitive to composition changes than DUET and which analyses a much larger proportion of coal on the belt, thus eliminating some key sources of analysis error

  11. 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

  12. 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...

  13. Mineralogy and chemistry of conventional and fluidised bed coal ashes

    OpenAIRE

    Sulovský P

    2002-01-01

    Coal combustion residues represent very abundant inorganic waste materials. The change from conventional combustion of powdered North Bohemian brown coal to its combustion in fluidised bed boilers in several Czech power and heating plants calls for detailed mineralogical and geochemical characterisation of the combustion residues. The main differences between fly ashes from both combustion systems result from different burning temperatures and differing systems of desulphurisation (coeval wit...

  14. Synthesis of zeolites from coal fly ash: an overview

    OpenAIRE

    Querol, Xavier; Moreno, N.; Umaña, J.C.; A. Alastuey; Hernández Chiva, Emilio; López-Soler, A.; Plana, F.

    2002-01-01

    Coal combustion by-products production in USA and EU is estimated in around 115 million tons per year. A large portion of this production is accounted for the coal fly ash (CFA). Cement and concrete manufacturing consumes most of the CFA produced. Zeolite synthesized from CFA is a minor but interesting product, with high environmental applications. Zeolites may be easily obtained from CFA by relatively cheap and fast conversion processes. This paper provides an overview on the methodologies f...

  15. Ash fusion temperatures and the transformations of coal ash particles to slag

    Energy Technology Data Exchange (ETDEWEB)

    Wall, T.F.; Creelman, R.A.; Gupta, R.; Gupta, S. [Univ. of Newcastle (Australia)

    1996-10-01

    A mechanistic study is detailed in which coal ash is heated with the shrinkage and electrical resistance measured continuously up to a temperature of 1600{degrees}C. The temperatures corresponding to rapid rates of shrinkage are shown to correspond to the formation of eutectics identified on phase diagrams. Samples where therefore heated to these temperatures, cooled rapidly and examined with an SEM to identify the associated chemical and physical changes. The progressive changes in the range of chemical analysis (from SEM), the extent of undissolved ash particles and porosity are then quantified and related to the shrinkage events and standard ash fusion temperatures.

  16. Ash fusion temperatures and the transformations of coal ash particles to slag

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, S.; Wall, T.F.; Creelman, R.A.; Gupta, R. [Univ. of Newcastle, Callaghan (Australia)

    1996-12-31

    A mechanistic study is detailed in which coal ash is heated with its shrinkage measured continuously up to a temperature of 1600{degrees}C. The temperatures corresponding to the rapid rate of shrinkage are shown to correspond to the formation of eutectics identified on phase diagrams. Samples were therefore heated to these temperatures, cooled rapidly and examined with an SEM to identify the associated chemical and physical changes. The progressive changes in the range of chemical analysis (from SEM), the extent of undissolved ash particles and porosity were then quantified and related to homogenization, viscosity and ash fusion mechanisms.

  17. Leaching behaviour of elements from coal combustion fly ash : an overview

    OpenAIRE

    Izquierdo, Maria; Querol, Xavier

    2012-01-01

    Coal-based power generation produces over 750 Mt of coal ash per year globally, but under 50% of world production is utilised. Large amounts of fly ash are either stored temporarily in stockpiles, disposed of in ash landfills or lagooned. Coal ash is viewed as a major potential source of release of many environmentally sensitive elements to the environment. This paper encompasses over 90 publications on coal fly ash and demonstrates that a large number of elements are tightly bound to fly ash...

  18. Dissolution of lime into synthetic coal ash slags

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, L.; Wang, Shen Mao; Wall, T.; Lucas, J. [Newcastle Univ. (Australia)] [and others

    1996-12-31

    One of the alternate processes presently being investigated to produce electrical power from coal is Integrated Gasification Combined Cycle (IGCC). The ash that remains when the coal is gasified in this process, is removed by granulating the molten ash at 1400 - 1500{degrees}C, To reduce the melting temperature of the coal ash to this level, a flux, usually limestone, is added with the cow to the gasifier. The rate of dissolution of the flux is uncertain. This paper reports the investigation of the rate of time dissolution into synthetic coal ashes, consisting of SiO{sub 2}, Al{sub 2}O{sub 3} and CaO. Results previously reported have shown that the free dissolution of fine particles (50-200 {mu}m) is mass transfer controlled. To investigate forced dissolution, a high temperature viscometer was used to rotate a cylinder of lime in the molten slag for a given period. At temperatures between 1450{degrees}C and 1656{degrees}C, reaction products of 3CaO.SiO{sub 2}/3CaOAl{sub 2}O{sub 3}, 2CaO.SiO{sub 2}/3CaO.Al{sub 2}O{sub 3}/12CaO,7Al{sub 2}O{sub 3} form around the lime pellet. The concentration gradient involved in the mass transfer was defined, and initial studies of the diffusion coefficients were completed.

  19. 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

  20. Mode of occurrence of arsenic in feed coal and its derivative fly ash, Black Warrior Basin, Alabama

    Science.gov (United States)

    Zielinski, R.A.; Foster, A.L.; Meeker, G.P.; Brownfield, I.K.

    2007-01-01

    An arsenic-rich (As = 55 ppm) bituminous feed coal from the Black Warrior Basin, Alabama and its derivative fly ash (As = 230 ppm) were selected for detailed investigation of arsenic residence and chemical forms. Analytical techniques included microbeam analysis, selective extraction, and As K-edge X-ray absorption fine-structure (XAFS) spectroscopy. Most As in the coal is contained in a generation of As-bearing pyrite (FeS2) that formed in response to epigenetic introduction of hydrothermal fluids. XAFS results indicate that approximately 50% of the As in the coal sample occurs as the oxidized As(V) species, possibly the result of incipient oxidation of coal and pyrite prior to our analysis. Combustion of pyrite and host coal produced fly ash in which 95% of As is present as As(V). Selective extraction of the fly ash with a carbonate buffer solution (pH = 10) removed 49% of the As. A different extraction with an HCl-NH2OH mixture, which targets amorphous and poorly crystalline iron oxides, dissolved 79% of the As. XAFS spectroscopy of this highly acidic (pH = 3.0) fly ash indicated that As is associated with some combination of iron oxide, oxyhydroxide, or sulfate. In contrast, a highly alkaline (pH = 12.7) fly ash from Turkey shows most As associated with a phase similar to calcium orthoarsenate (Ca3(AsO4)2). The combined XAFS results indicate that fly ash acidity, which is determined by coal composition and combustion conditions, may serve to predict arsenic speciation in fly ash.

  1. Natural radioactivity of coals from Upper Silesian Coal Basin and their ash content

    International Nuclear Information System (INIS)

    The results of the study of natural radioactivity of Upper Silesian's coal are presented. The histograms of contents of 226Ra, 228Ra and 40K in the main groups of carbon layers are given. Analysis of correlations between contents of natural radionuclides and ash content in different coal layers was made. The correlations were stated. 12 refs., 7 figs., 4 tabs. (author)

  2. The reaction of acid mine drainage with fly ash from coal combustion

    International Nuclear Information System (INIS)

    The placement of alkaline fly ash in abandoned, reclaimed or active surface coal mines is intended to reduce the amount of acid mine drainage (AMD) produced at such sites by neutralization, inhibition of acid forming bacteria, encapsulation of the pyrite or water diversion. A continuing concern with this application is the potential release of trace elements from the fly ash when it is placed in contact with AMD. To investigate the possible release of antimony, arsenic, barium, boron, cadmium, chromium, cobalt, copper, lead, nickel, selenium, and zinc from fly ash, a series of column leaching tests were conducted. A one kg fly ash sample, placed in a 5-cm by 1 m acrylic columns, was leached at a nominal rate of 250 mL/d for between 30 and 60 days. The leachant solutions were deionized water, and dilute solutions of sulfuric acid and ferric chloride. Leaching tests have been completed on 28 fly ash samples. leachate data, analyzed as the mass extracted with respect to the concentration in the solid, indicate that the release of trace elements is variable, with only barium and zinc extracted at greater than 50 pct of the amount present in the original sample. As a comparison, water quality changes have been monitored at three sites where fly ash grout was injected after reclamation to control AMD. When compared before and after grouting, small increases in pH and decreases in acidity at discharge points were observed. Concentrations of trace metals were found to be comparable in treated and untreated areas. When grouted and ungrouted areas were compared, the effect of the fly ash was shown to be localized in the areas of injection. These studies indicated that when fly ash is used as a reagent to control of AMD, the release of trace elements is relatively small

  3. Phase-mineral and chemical composition of coal fly ashes as a basis for their multicomponent utilization. 1. Characterization of feed coals and fly ashes

    Energy Technology Data Exchange (ETDEWEB)

    Stanislav V. Vassilev; Rosa Menendez; Diego Alvarez; Mercedes Diaz-Somoano; M. Rosa Martinez-Tarazona [Bulgarian Academy of Sciences, Sofia (Bulgaria). Central Laboratory of Mineralogy and Crystallography

    2003-10-01

    The phase-mineral and chemical composition of feed coals and their fly ashes (FAs) produced in four large Spanish thermo-electric power stations was characterized as a basis for multicomponent FA utilization. The feed fuels used are bituminous coals, semi-anthracites and anthracites with high detrital mineral abundance and mixed carbonate and sulphide sulphate authigenic mineral tendency. Their mineral composition includes quartz, kaolinite, illite muscovite, pyrite, chlorite, plagioclase, K-feldspar, gypsum, siderite, calcite, dolomite, marcasite, montmorillonite, jarosite, and ankerite. The FAs studied have aluminosilicate composition with higher concentrations of alkaline and alkaline-earth oxides than Fe oxide. Elements such as Ag, As, Ba, Cr, Cs, Li, P, Sb, Sc, Sn, Sr, Ti, V, Zn, and Zr are relatively enriched in these FAs in comparison with the respective mean values for bituminous coal ashes worldwide. The FAs consist basically of aluminosilicate glass, to a lesser extent of mineral matter (with high silicate abundance and dominant oxide tendency) and moderate char occurrence. The phase-mineral composition (in decreasing order of significance) of these FAs is normally glass, mullite, quartz, char, kaolinite metakaolinite, hematite, cristobalite, plagioclase, K-feldspar, melilite, anhydrite, wollastonite, magnetite and corundum plus 42 important accessory minerals or phases. A scheme of conventional separation procedures was applied to recover sequentially six initial and potentially useful and/or hazardous products from FAs, namely: (1) a ceramic cenosphere concentrate; (2) a water-soluble salt concentrate; (3) a magnetic concentrate; (4) a char concentrate; (5) a heavy concentrate; and finally (6) an improved FA residue. 29 refs., 6 figs., 10 tabs.

  4. Correction of pair production gauge ash determinations for changes in coal ash composition

    International Nuclear Information System (INIS)

    The ash content of coal can be determined by a technique based on pair production (PP). The PP technique has been previously proved in the laboratory and in the field, and five commercial PP gauges are in routine use at coal washeries in Australia. However for some applications on coals of highly variable ash composition, there is a need for improved accuracy. Calculations and experiments have been made to investigate two methods of improving PP gauge accuracy for coals with highly variable ash composition. The first combines the PP gauge measurement with measurements of the low-energy part of the PP gauge spectrum and the second is done in conjuction with separate low and high energy γ-ray transmission measurements. Calculations show that these methods can correct the PP gauge assay exactly when the concentration of a single high-Z element in the ash varies. When more than one element varies, the error reduction is less and depends on the elements and their variations. Experiments with a group of samples from Blackwater, Queensland showed that gauge accuracy improved by about 20% relative using the first method. Use of the second method on two groups of samples from Blackwater and South Africa produced about 15% improvement. There was no reduction in error when either method was used on a third group of samples from the Hunter Valley New South Wales. (author)

  5. The use of coal fly ash for soil stabilization

    Energy Technology Data Exchange (ETDEWEB)

    Brown, T.H.; Brown, M.A.; Sorini, S.S.; Huntington, G.

    1991-12-01

    The objective of this work was to examine the potential use of Wyoming subbituminous coal fly ash materials for cementation of soil materials. Specimens made from Laramie River (LR) fly ash had higher unconfined compression strength and more brittleness than the Specimens made with Dave Johnston (DJ) fly ash. However, soil/DJ fly ash mixtures that were cured for 28 days had relatively good strengths without the brittleness that the LR specimens developed. These characteristics of the DJ fly ash may be important attributes for road stabilization applications. The detailed mineralogical evaluation provides some insight into which minerals may enhance development of strength in these materials. In general, selective dissolution of the soil/fly ash mixtures shows that many of the potentially toxic elements (e.g., B, Cr, Fe, Mn, Ni, Pb) are associated with the sulfide phase (HNO{sub 3} extractable) and with the residual material. In this study, the dynamics of elemental release from the element pools did not result in toxic conditions. The formation of colloidal material capable of mobilizing potentially toxic elements was not found in the soil/fly ash mixtures. Apparently, the high pH of the materials enhanced immobilization of the high molecular weight material.

  6. Measurement of the ash content of coal

    International Nuclear Information System (INIS)

    An apparatus suitable for determining the noncombustible content of coal in railroad cars or other transportation containers consists of a neutron source, a detector of gamma rays of a predetermined energy characteristic of aluminum 28 and a readout device

  7. 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.

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

    Science.gov (United States)

    Mõtlep, Riho; Sild, Terje; Puura, Erik; Kirsimäe, Kalle

    2010-12-15

    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. PMID:20855159

  9. Clay formation and metal fixation during weathering of coal fly ash

    International Nuclear Information System (INIS)

    The enormous and worldwide production of coal fly ash cannot be durably isolated from the weathering cycle, and the weathering characteristics of fly ash must be known to understand the long-term environmental impact. The authors studied the weathering of two coal fly ashes and compared them with published data from weathered volcanic ash, it's closest natural analogue. Both types of ash contain abundant aluminosilicate glass, which alters to noncrystalline clay. However, this study reveals that the kinetics of coal fly ash weathering are more rapid than those of volcanic ash because the higher pH of fresh coal fly ash promotes rapid dissolution of the glass. After about 10 years of weathering, the noncrystalline clay content of coal fly ash is higher than that of 250-year-old volcanic ash. The observed rapid clay formation together with heavy metal fixation imply that the long-term environmental impact of coal fly ash disposal may be less severe and the benefits more pronounced than predicted from previous studies on unweathered ash. Their findings suggest that isolating coal fly ash from the weathering cycle may be counterproductive because, in the long-term under conditions of free drainage, fly ash is converted into fertile soil capable of supporting agriculture

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

    OpenAIRE

    Ricardo Pires dos Santos; Jorge Martins; Carlos Gadelha; Benildo Cavada; Alessandro Victor Albertini; Francisco Arruda; Mayron Vasconcelos; Edson Teixeira; Francisca Alves; José Lima Filho; Valder Freire

    2014-01-01

    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 c...

  11. 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.

  12. Coal fly ash as a resource for rare earth elements.

    Science.gov (United States)

    Franus, Wojciech; Wiatros-Motyka, Małgorzata M; Wdowin, Magdalena

    2015-06-01

    Rare earth elements (REE) have been recognised as critical raw materials, crucial for many clean technologies. As the gap between their global demand and supply increases, the search for their alternative resources becomes more and more important, especially for the countries which depend highly on their import. Coal fly ash (CFA), which when not utilised is considered waste, has been regarded as the possible source of many elements, including REE. Due to the increase in the energy demand, CFA production is expected to grow, making research into the use of this material a necessity. As Poland is the second biggest coal consumer in the European Union, the authors have studied different coal fly ashes from ten Polish power plants for their rare earth element content. All the fly ashes have a broadly similar distribution of rear earth elements, with light REE being dominant. Most of the samples have REE content relatively high and according to Seredin and Dai (Int J Coal Geol 94: 67-93, 2012) classification can be considered promising REE raw materials. PMID:25613802

  13. Usage of Ash from Coal incineration in Wuhai, China

    OpenAIRE

    Sun, Shiyu

    2007-01-01

    This master thesis has been carried out at Industrial Ecology at Royal Institute ofTechnology, KTH, in cooperation with Swedish Environmental Research Institute, IVL.This thesis discussed the usage of the ash from coal incineration in Wuhai, Inner Mongolia,China by studying and analyzing the fly ash from the case plant, the North Power Company.In the first part, there are some background information about the study area, like Wuhaicity and the case plant, the North Power Company. The study fo...

  14. Environmental impact of coal ash on tributary streams and nearshore water or Lake Erie. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Wood, K.G.

    1978-08-01

    The environmental impact of coal ash disposal at a landfill site in north-central Chautauqua County, New York was studied from June 1975 through July 1977. Water samples taken from wells, ponds, and streams at 67 sites were analyzed for specific conductance, pH, alkalinity, arsenic, calcium, cadmium, chloride, chromium, copper, iron, magnesium, manganese, potassium, selenium, sodium, sulfate and zinc. Evidence suggests that ponds at the landfill were high in Ca, Fe, Mg, Mn, and SO/sub 4/ compared to control pands. A stream adjacent to the site contained greater Mn (207 ug/1) and SO/sub 4/ (229 ppm) than control streams. Shallow alkaline test wells in the landfill had elevated As, Ca, and Se. Acid-neutral test wells had elevated As, Ca, Cr, Mg and Mn. Household wells in the vicinity of the landfill showed no evident contamination from the landfill. Average iron concentrations in the biota were tripled, and manganese concentrations doubled in biota affected by the coal ash dump. However, any effects of the disposal area on the distribution of the biota could not be separated from effects of varying environment factors such as water movements, substrate composition and food availability. No harmful effects could be demonstrated on the biota in the creek which flowed past the disposal area.

  15. 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 up to C9, a performance attesting the hierarchal pore structure. The preliminary techno-economic feasibility assessment demonstrates a net energy saving of 75% and cost saving of 63% compared to the commercial zeolite manufacturing process.

  16. Fluidized bed combustion of high ash Spanish coals

    Energy Technology Data Exchange (ETDEWEB)

    Pis, J.J.; Fuertes, A.B.; Artos, V.; Rubiera, F.; Marban, G.; Camibano, J. (Instituto Nacional del Carbon, Oviedo (Spain))

    1991-01-01

    The main scope of this work has been to study the fluidized bed combustion behaviour of four high ash content coals of different rank from the Asturian basin (SPAIN). The effect of the operation variables (temperature, fluidizing velocity and excess air) on combustion efficiency was studied. Combustion efficiency increases with the temperature and more slightly with air excess, and decreases with fluidizing velocity. Temperature and air excess determine the carbon concentration in the bed, which depends on the reactivity. Carbon loss by elutriation represents over 80% of the whole loss. The attrition constants for each coal were calculated; values obtained were higher for the bituminous coals than for the semianthracite coals. 8 refs., 8 figs., 2 tabs.

  17. Mineralogy and chemistry of conventional and fluidised bed coal ashes

    Directory of Open Access Journals (Sweden)

    Sulovský P

    2002-03-01

    Full Text Available Coal combustion residues represent very abundant inorganic waste materials. The change from conventional combustion of powdered North Bohemian brown coal to its combustion in fluidised bed boilers in several Czech power and heating plants calls for detailed mineralogical and geochemical characterisation of the combustion residues. The main differences between fly ashes from both combustion systems result from different burning temperatures and differing systems of desulphurisation (coeval with combustion / post-combustion. Both these factors influence the chemical and phase compositions as well as the speciation of trace elements. The study further shows that the validity of the surface enrichment model (Linton et al. 1975 can be limited.

  18. 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, development of expanded information on the environmental performance of CCBs in utilization settings included the following: (1) Development of information on physical properties and engineering performance for concrete, soil-ash blends, and other products. (2) Training of students through participation in CARRC research projects. (3) Participation in a variety of local, national, and international technical meetings, symposia, and conferences by presenting and publishing CCB-related papers.

  19. 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

  20. Coal fly ash as a resource for rare earth elements

    OpenAIRE

    Franus, Wojciech; Wiatros-Motyka, Małgorzata M.; Wdowin, Magdalena

    2015-01-01

    Rare earth elements (REE) have been recognised as critical raw materials, crucial for many clean technologies. As the gap between their global demand and supply increases, the search for their alternative resources becomes more and more important, especially for the countries which depend highly on their import. Coal fly ash (CFA), which when not utilised is considered waste, has been regarded as the possible source of many elements, including REE. Due to the increase in the energy demand, CF...

  1. Thermal expansion of slag and fly ash from coal gasification

    OpenAIRE

    Aineto, Mónica; Acosta, Anselmo; Rincón López, Jesús María; Romero, Maximina

    2006-01-01

    Integrated gasification in combined cycle (IGCC) is an electrical power generation system, which is characterized to be a clean coal technology different than conventional process in combustible treatment. IGCC process gives rise to inorganic solid wastes in the form of vitreous slag and fly ashes with singular thermal properties. The gasification of the fuel takes place at high temperature and pressure in reducing atmosphere. Under those conditions, gases such as H2, N2 or CO, which are the ...

  2. 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

  3. 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.

  4. Ash fusion temperatures and their association with the transformations of coal ash particles to slag

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, S.K.; Wall, T.F.; Gupta, R.P. [Cooperative Research Centre for Black Coal Utilisation, Newcastle, NSW (Australia); Creelman, R.A. [Creelman (R.A.) and Associates, Sydney, NSW (Australia)

    1997-04-01

    Ash deposition on furnace walls in PF (pulverized fuel) furnaces is called slagging when it occurs in the high temperature areas of furnaces directly exposed to flame radiation and fouling in other regions such as tubes in the convection section of the boiler. There are well documented shortcomings of certain approaches relating to their uncertainties as predictive tools for plant performance such as poor repeatability and re-producibility of ash fusion measurements. The nature of physical and chemical changes occurring during melting of coal ash has been investigated in the current study to provide an alternative procedure to the ash fusion test. Shrinkage measurements are frequently used in metallurgy and ceramic science to study the physical properties of materials at high temperatures. The output of this experiment provides three to four `peaks` (maximum rate of shrinkage with temperature) of different intensity and at different temperatures which are related to melting characteristics of the sample. It was concluded that shrinkage extents exceeding 50 percent indicated that the effect of the ash particle size is of secondary importance compared to ash chemistry in determining shrinkage levels, with fine particles giving rapid shrinkage events 10 degrees C lower in temperature. (author). 7 figs., refs.

  5. Groundwater impact studies at three Ontario Hydro coal ash landfills

    International Nuclear Information System (INIS)

    Ontario Hydro has produced on the order of 21 million Mg of coal fly ash over the past 40 years, of which, 80% has gone to various landfill sites in the province of Ontario. Hydrogeologic investigations have been performed in the vicinity of three Ontario Hydro coal ash landfill sites to assess the environmental impact of fly ash landfilling on the local groundwater regime. Two of the waste management facilities are associated with thermal generating stations (Lambton TGS and Nanticoke TGS) and are founded on relatively impermeable clay deposits. The third site, Birchwood Park, is a former sand and gravel pit for which the landfill design did not incorporate the use of a liner material. The rates of groundwater flow through the overburden materials a the three sites vary from less than 1 cm/a at the Lambton TGS site, to between 3.45 cm/a and 115 cm/a at contaminant transport at these sites also varies from being controlled by molecular diffusion to advection. This paper discusses the migration rates of contaminants from fly ash leachate at each of the three sites with implications to landfill containment and design

  6. On-line analyzer of ash content in coal

    International Nuclear Information System (INIS)

    The radioisotope method for ash content measurement consists in effective atomic number (Z) determination. The considerable difference between Z of combustible and noncombustible coal phases is used. Due to changeable chemical composition and physical structure of the material, the radiations with two different energies are used and their attenuation and scattering is registered. In order to avoid the impact of the variable size and surface of the material on the transportation line, a wide-surface proportional detector is used. It registers the scattering of X-ray radiation (Pu-238 or Cd-109) from the coal surface of about 0.1 m2. The gamma radiation (Am-241) passing through the coal is registered by a scintillation probe. The developed ash-meter works with a bound torsion scales that continuously transmits signal of the instant load and the total material quantity. The measurement system is developed on the basis of a PC AT industrial type. All system elements, analytical software and the construction itself are Bulgarian made. The sensitivity, accuracy and measurement rate of the equipment are in no way inferior to the best foreign analogues and excel the ash-meters from former East Germany and Czechoslovakia. The analyzer is installed and at present is being tested in real production conditions at Maritza-East-2 Thermal Power Plant. (author)

  7. Ash chemistry and mineralogy of an Indonesian coal during combustion. Part 1 Drop-tube observations

    Energy Technology Data Exchange (ETDEWEB)

    Vuthaluru, H.B. [Department of Chemical Engineering, Curtin University of Technology, Bentley, Perth Western 6102 (Australia); French, D. [CSIRO Energy Technology, Lucas Heights Science and Technology Centre, Private Mail Bag 7, Bangor New South Wales 2234 (Australia)

    2008-06-15

    The paper reports a systematic and comprehensive laboratory investigation into the ash chemistry and mineralogical changes undergone by a low-rank Indonesian coal during combustion. Combustion experiments conducted in a drop-tube furnace included ash formation experiments (using cyclone and filter arrangement) under closely controlled conditions in the range of 1200-1400 C and deposition experiments at a probe temperature of 750 C. Tests conducted with raw coal, coal/additive mixtures and washed coal indicated significant changes in ash characteristics. Of the ash formation and deposit samples examined, the raw coal + bauxite showed the lowest glass content and high contents of corundum indicating low ash deposition propensities. When compared to the ash formation samples, the deposit samples showed even significantly lower glass contents and were enriched in quartz. With the exception of the raw coal + bauxite sample, all are characterized by high silica and iron and moderate aluminium contents. In contrast, the raw coal + bauxite sample have low silica and much higher alumina contents which is in agreement with XRD observations. QEMSCAN trademark results showed that the ash particles are sparsely distributed suggesting lack of a deposit initiation layer. Experimental observations suggest that the use of raw coal with bauxite would appear to offer the best performance with respect to handling ash-related issues. Present findings are of practical significance to power utilities employing Indonesian coal as there is no comprehensive work reported in the literature on ash chemistry and mineralogy of such coals. (author)

  8. Mullitization of black coal fly ashes

    OpenAIRE

    Mria Kunierov; Mria Pra?kov; Dalibor Matsek; Vladimr ?ablk

    2011-01-01

    In this paper are presented the results of experiments focused on the study of thermal treatment influence of selected black coal flyashes from the heating plant in Kosice and the power plant in Vojany. The study was realized with original not pretreated samples.The obtained results confirmed that after the thermal treatment of both samples the phases change of material occurred. At 1050 C,the decrease of amorphous phase was remarked, being transformed to the mullite and spinel. This inform...

  9. 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.

  10. Low-level radiation in coals utilized and ashes produced at New York State electric utilities

    International Nuclear Information System (INIS)

    Eight coal-fired power plants in New York State were sampled for coal, fly ash and bottom ash. Samples were analyzed for uranium 238, uranium 235, uranium 234, thorium 232, thorium 230, radium 226, lead 210, polonium 210, radon 222. The leachate of six fly ash samples was analyzed for all of the above except radon 222. Some data on fly ash analysis are included

  11. Analytical methods relating to mineral matter in coal and ash from coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Creelman, R.A. [Ultra-Systems Technology Pty. Ltd., Indooroopilly, Qld. (Australia)

    2002-07-01

    The paper begins by describing the minerals that occur in coal, as well as trace elements. The testing methods that are then described include those that are in the main the standard tools for the examination and assessment of minerals in coal and ash. The techniques discussed include optical and beam techniques, X-ray methods and a variety of other useful methods. 12 refs.

  12. 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.

  13. Effects of mineralizers on fusion temperature of domestic coal ash

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Jin-Wook; Han, Choon [Kwangwoon University, Seoul(Korea); Lim, Byeong-Seon [Korea Bosch Ltd., Seoul(Korea); Lee, Myoung-Sup; Lee, Sang-Hoon [Korea Resources Corp., Seoul(Korea); Lee, Bong-Han; Yoo, Jae-Sang; Seo, Hyoung-Seok [Ssangyong Cement Industrial Co., Ltd., Seoul(Korea)

    2001-12-31

    Considering compositions, domestic coal ash can be used as raw material for cement. However, the high fusion temperature of domestic coal ash(>1600 deg.C) prohibits using because the combustion temperature of clinker is around 1450 deg.C. Therefore, mineralizers are needed to lower the ash fusion temperature(AFT) and effects of mineralizers were investigated in this study. For three coal ashes from Tae-baek area, pure and mixed mineralizers(CaO, MgO, Fe{sub 2}O{sub 3}, Na{sub 2}CO{sub 3}) were added. Results showed that AFT were lowered to around 1450 deg.C by adding CaO 5-8 wt.%(1360-1471 deg.C), MgO 2-5 wt.%(1360-1480 deg.C), and Fe{sub 2}O{sub 3} 2-5 wt.%(1395-1490 deg.C) respectively. Especially, the lowest AFT(1120-1147 deg.C) could be achieved by adding 30 to 40 wt.% of CaO. When 20 to 30 wt.% of mixed mineralizers(CaO : MgO = 1 : 1) were added, AFT was lowered to 1130-1153 deg.C which was the lowest temperature with mixed mineralizer. Also, CaO was recognized as the governing mineralizer on AFT. Recognizing that basic oxides took the main role of mineralizers, the model equation was proposed to estimate AFT. Consequently, simulated results by the model equation represented the measured AFT successfully. (author). 12 refs., 4 tabs., 8 figs.

  14. Fly ash formation and sulphation during the combustion of brown coal

    Energy Technology Data Exchange (ETDEWEB)

    Domazetis, G. (and others)

    1987-12-01

    This report presents an overview of investigations into the fly ash formation and sulphation process that occurs when brown coal is burnt. A code has been developed to simulate the chemistry of ash formation. The results of this project show that for the coals considered the chemistry of sodium species in a coal flame is central to the ash formation and fouling. Aluminium based additives have been tested on two Loy Yang coals. The tests show that the additives exert a pronounced influence on ash formation, probably via changes in the heterogeneous condensation of sodium compounds.

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

    OpenAIRE

    Nabih K.; Kada M.K.; Hmiri M.; Hamsi N.

    2014-01-01

    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...

  16. 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

    OpenAIRE

    Denise Alves Fungaro; Juliana de Carvalho Izidoro

    2006-01-01

    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 concen...

  17. Radioactivity of coal and ashes from Figueira coal power plant in Brazil

    International Nuclear Information System (INIS)

    The Figueira coal-fired power plant (CFPP) is among the Brazilian CFPP which presents higher uranium concentration. Gamma-ray spectrometry was used to determine 238U, 226Ra, 210Pb, 232Th and 40K contents in pulverized coal, furnace bottom ash and fly ash samples. The natural radionuclide concentrations in pulverized coal ranged from 813 to 2609 Bq x kg-1 for U series and from 22 to 40 Bq x kg-1 for 232Th. The fly ash fraction gave concentrations ranging from 1442 to 14641 Bq x kg-1, for uranium series. The same enrichment factor was observed for 238U, 226Ra and 232Th. Only 210Pb and stable Pb presented a high enrichment factor for the last stage filter fly ash. The concentration of the uranium series found in the ashes is close to the limit adopted by the Brazilian guideline (CNEN-NN-4.01).22 Therefore, it is advisable to evaluate the environmental impact of the installation. (author)

  18. Radioactivity of coal and ashes from Figueira coal power plant in Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Flues, M.; Camargo, I.M.C.; Silva, P.S.C; Mazzilli, B.P.

    2006-12-15

    The Figueira coal-fired power plant (CFPP) is among the Brazilian CFPP which presents higher uranium concentration. Gamma-ray spectrometry was used to determine U-238, Ra-226, Pb-210, Th-232 and K-40 contents in pulverized coal, furnace bottom ash and fly ash samples. The natural radionuclide concentrations in pulverized coal ranged from 813 to 2609 Bq{sup -}kg{sup -1}for U series and from 22 to 40 Bq{sup -}kg{sup -1} for Th-232. The fly ash fraction gave concentrations ranging from 1442 to 14641 Bq{sup -}kg{sup -1}, for uranium series. The same enrichment factor was observed for U-238, Ra-226 and Th-232. Only Pb-210 and stable Pb presented a high enrichment factor for the last stage filter fly ash. The concentration of the uranium series found in the ashes is close to the limit adopted by the Brazilian guideline (CNEN-NN-4.01). Therefore, it is advisable to evaluate the environmental impact of the installation.

  19. 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.

  20. 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...... of flue gas cleaning equipment. This survey includes discussions on the inorganic constituents transformation during straw and coal combustion, alkali-ash and alkali sulfur reactions, a survey of power plant and test rig co-firing experiments, a discussion of equilibrium calculations, a discussion of...... alkali getter experiments and a discussion of modeling of alkali reaction with kaolin. Presently there is still a need for a better understanding of especially the reaction of potassium with coal ash, thereby making better predictions of co-firing ash properties....

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

    Science.gov (United States)

    Skvra, Frantisek; Kopeck, Lubomr; Smilauer, Vt; 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. PMID:19303704

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

    International Nuclear Information System (INIS)

    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 Mn [-(Si-O)z-Al-O]n.wH2O, that forms during the alkaline activation, was examined by means of microcalorimetry, XRD, TGA, DSC, MIP, FTIR, NMR MAS (29Si, 27Al, 23Na), 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 86.2 kJ/mol. The X-ray diffraction analysis revealed no additional crystalline phases associated with geopolymer formation. Over several weeks, the 29Si NMR spectrum testified a high degree of polymerization and Al penetration into the SiO4 tetrahedra. The 23Na NMR MAS spectrum hypothesized that sodium is bound in the form of Na(H2O)n rather than Na+, thus causing efflorescence in a moisture-gradient environment. As and Cr6+ are weakly bonded in the geopolymer matrix, while excellent immobilization of Zn2+, Cu2+, Cd2+, and Cr3+ are reported.

  3. 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

  4. An appraisal of the potential use of fly ash for reclaiming coal mine spoil.

    Science.gov (United States)

    Ram, Lal C; Masto, Reginald E

    2010-01-01

    Growing dependence on coal-fired power plants for electrical generation in many countries presents ongoing environmental challenges. Burning pulverized coal in thermal power plants (TPPs) generates large amounts of fly ash (FA) that must be disposed of or otherwise handled, in an environmentally-sound manner. A possible option for dealing with fly ash is to use it as an amendment for mine spoil or other damaged soil. It has been demonstrated through studies in India and other countries that FA alone or in combination with organic or inorganic materials can be used in a productive manner for reclamation of mine spoil. The characteristics of FA, including silt-sized particles, lighter materials with low bulk density (BD), higher water holding capacity, favorable pH and significant concentrations of many essential plant nutrients, make it a potentially favorable amendment for mine spoil reclamation. Studies have indicated that the application of FA has improved the physical, chemical and biological qualities of soil to which it is applied. The release of trace metals and soluble salts from FA could be a major limitation to its application. This is particularly true of fresh, un-weathered FA or acidic FA, although perhaps not a concern for weathered/pond ash or alkaline FA. Some potential contaminants, especially metals and other salt ions, could be immobilized and rendered biologically inert by the addition of certain inorganic and organic amendments. However, in view of the variability in the characteristics of FAs that are associated with location, feed coal, combustion conditions and other factors, the suitability of a particular FA for a specific soil/mine spoil needs to be critically evaluated before it is applied in order to maximize favorable results and eliminate unexpected consequences. FA generated in India tends to be mostly alkaline, with lower levels of trace elements than are often found in FAs from other countries. The concentrations of potential chemical stressors, predominantly metals, in Indian FAs are often less than established or proposed permissible limits and are thus better suited for soil application. A major logistic limitation to the use of FA could be the cost involved in transport of ash from production to utilization sites. PMID:19914766

  5. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Querol, X.; Moreno, N.; Alastuey, A.; Juan, R.; Andres, J.M.; Lopez-Soler, A.; Ayora, C.; Medinaceli, A.; Valero, A. [CSIC, Barcelona (Spain)

    2007-07-01

    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 m{sup 3} reactor of Clariant SA (Barcelona, Spain). The results allowed obtaining 1.1 and 2.2 tonnes of zeolitic material with 40 and 55% of NaP1 content, in two single batch experiments of 24 and 8 hours, for Teruel and Narcea fly ashes, respectively. The cation exchange capacities (CEC) of the final product reached 2.0 and 2.7 meq g{sup -1} for Teruel and Narcea zeolitic material, respectively, which are very close to the usual values reached by the high quality natural zeolitic products. Finally, with the aim of testing possible applications of the commercial NaP1-IQE and pilot plant NaP1-Narcea zeolitic products in water decontamination, efficiency for metal uptake from waste waters from electroplating baths was investigated.

  7. Determination of slagging behavior of various coal ash samples by using DTF

    Energy Technology Data Exchange (ETDEWEB)

    Kim, H.T.; Choi, B.C.; Park, S.W.

    1999-07-01

    The objective of this study is to investigate slagging behavior of various ash samples with the conjunction to the properties of ashes and original coal such as concentration of each ash components, ash slagging temperature and slag viscosity. To simulate actual ash melting condition in coal combustion as well as gasification, DTF (drop tube furnace) is utilized for the acquisition of slag sample with different reaction condition. The sampled slag is photographed for the visual inspection and the shape of the slag is evaluated with ash properties. The sampled ash slag is also analyzed with XRD for the determination of phase transition during the ash melting. Furthermore, coal ashes are processed with Ash Fusion Determinator for the fusion temperature and High-Temperature Viscometer for the slag viscosity. Such ash-related properties are also determined by empirical formulation for the refinement of the result. So far, three different coal samples, Alaska, Datong, Cyprus are investigated. For the 3 ash samples, slag formation shows similar shape in combustion as well as gasification condition and completely different shape with different coal types. Alaska slag, which represents higher fluidity, is penetrated into alumina disk so that small half-cone shape of slag is produced. However, Cyprus slag is formed with more circular shape of sphere and Datong slag represents an in-between shape. More coal samples will be studied for the determination of slag behavior. The shape data will be analyzed with ash composition, fluidity behavior and ash fusion determination of original coal. Such relationship will be the baseline to determine the operation parameter of slag removal in the 3 ton/day coal gasifier located in the Ajou University, Suwon, Korea.

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

    Science.gov (United States)

    Tiwari, M; Sahu, S K; Bhangare, R C; Ajmal, P Y; Pandit, G G

    2014-08-01

    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. PMID:24685495

  9. 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.

  10. 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. PMID:19854038

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

    International Nuclear Information System (INIS)

    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 (Na2SiO3) and 10 M sodium hydroxide (NaOH) solutions at mass ratio of Na2SiO3/NaOH of 1.5 and curing temperature of 65 deg. C for 48 h 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 35.0-44.0 MPa 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.

  12. Utilization of coal ash contributing to environment and power reduction. Sekitanbai no kankyo koken riyo to doryoku setsugen riyo no bun prime ya

    Energy Technology Data Exchange (ETDEWEB)

    Yasuda, M.. (Electric Power Development Co. Ltd., Tokyo (Japan))

    1991-09-30

    Some techniques relating to the contribution to surrounding environment and power reduction of utilizing techniques of coal ash which is produced at the rate of 500,000,000 tons/year in this world are explained. Almost all coal ash produced in Japan originates from pulverized coal firing and the utilizing areas are as follows: (1) resource preserving area including the application to the asphalt filler; (2) product substituting area including the cement substitution; (3) industrial waste processing area including the deodorant; (4) mixing area with industrial waste including the recycling one after mixing with industrial waste and mixing with mud; (5) land planting area including soil improver and culture medium pelletized with industrial waste; and (6) seabed planting area including the surface lining on sludge area in seabed. Further, the effective cases of representative applications are as follows: When coal ash is used as the filler for asphalt concrete, the effect is raised by pulverizing coal ash followed by repressing to the filler form. When coal ash is used as the cement substitute, the concrete deterioration is prevented by suppressing the alkaline aggregate reaction. 5 refs.. 5 figs., 1 tab.

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

    OpenAIRE

    Jankovi? M.M.; Todorovi? D.J.; Nikoli? 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, Vin?a 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 ...

  14. Study on Thermal Insulation Zeolite by Coal Fly Ash

    OpenAIRE

    Huiping Song; Nan Zheng; Fangbin Xue; Fangqin Cheng

    2014-01-01

    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 crysta...

  15. Floating cultivation of marine cyanobacteria using coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, M.; Yoshida, E.; Takeyama, H.; Matsunaga, T. [Tokyo University of Agriculture and Technology, Tokyo (Japan). Dept. of Biotetechnology

    2000-07-01

    The aim was to develop improved methodologies for bulk culturing of biotechnologically useful marine cyanobacteria in the open ocean. The viability of using coal fly ash (CFA) blocks as the support medium in a novel floating culture system for marine microalgae was investigated. The marine cyanobacterium Synechococcus sp. NKBC 040607 was found to adhere to floating CFA blocks in liquid culture medium. The marine cyanobacterium Synechococcus sp. NKBG 042902 weakly adhered to floating CFA blocks in BG-11 medium. Increasing the concentration of calcium ion in the culture medium enhanced adherence to CFA blocks.

  16. 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.

  17. Utilization of coal ash/coal combustion products for mine reclamation

    International Nuclear Information System (INIS)

    Society's demand for an inexpensive fuel, combined with ignorance of the long term impacts, has left numerous scars on the Pennsylvania landscape. There are over 250,000 acres of abandoned surface mines with dangerous highwalls and water filled pits. About 2,400 miles of streams do not meet water quality standards because of drainage from abandoned mines. There are uncounted households without an adequate water supply due to past mining practices. Mine fires and mine subsidence plague many Pennsylvania communities. The estimated cost to reclaim these past scars is over $15 billion. The beneficial use of coal ash in Pennsylvania for mine reclamation and mine drainage pollution abatement projects increased during the past ten years. The increase is primarily due to procedural and regulatory changes by the Department of Environmental Protection (DEP). Prior to 1986, DEP required a mining permit and a separate waste disposal permit for the use of coal ash in backfilling and reclaiming a surface mine site. In order to eliminate the dual permitting requirements and promote mine reclamation, procedural changes now allow a single permit which authorize both mining and the use of coal ash in reclaiming active and abandoned pits. The actual ash placement, however, must be conducted in accordance with the technical specifications in the solid waste regulations

  18. 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.

  19. Airborne crystalline silica concentrations at coal-fired power plants associated with coal fly ash.

    Science.gov (United States)

    Hicks, Jeffrey; Yager, Janice

    2006-08-01

    This study presents measurements of airborne concentrations of respirable crystalline silica in the breathing zone of workers who were anticipated to encounter coal fly ash. Six plants were studied; two were fired with lignite coal, and the remaining four plants used bituminous and subbituminous coals. A total of 108 personal breathing zone respirable dust air samples were collected. Bulk samples were also collected from each plant site and subjected to crystalline silica analysis. Airborne dust particle size analysis was measured where fly ash was routinely encountered. The results from bituminous and subbituminous fired plants revealed that the highest airborne fly ash concentrations are encountered during maintenance activities: 0.008 mg/m3 to 96 mg/m3 (mean of 1.8 mg/m3). This group exceeded the threshold limit values (TLV) in 60% of the air samples. During normal production activities, airborne concentrations of crystalline silica ranged from nondetectable to 0.18 mg/m3 (mean value of 0.048 mg/m3). Air samples collected during these activities exceeded the current and proposed TLVs in approximately 54% and 65% of samples, respectively. Limited amounts of crystalline silica were detected in samples collected from lignite-fired plants, and approximately 20% of these air samples exceeded the current TLV. Particle size analysis in areas where breathing zone air samples were collected revealed mass median diameters typically between 3 microm and 8 microm. Bulk and air samples were analyzed for all of the common crystalline silica polymorphs, and only alpha quartz was detected. As compared with air samples, bulk samples from the same work areas consistently yielded lower relative amounts of quartz. Controls to limit coal fly ash exposures are indicated during some normal plant operations and during episodes of short term, but high concentrations of dust that may be encountered during maintenance activities, especially in areas where ash accumulations are present. PMID:16862716

  20. Radiological Considerations in the Production of Lightweight Concrete Based on Coal Ashes

    International Nuclear Information System (INIS)

    The common disadvantage of using high volumes of coal ashes (both bottom ash and fly ash) in lightweight concrete production is the presence in the ashes of trace amounts of heavy metals and natural radionuclides such as 226Ra, 232Th and 40K. Therefore, coal ashes are classified in many cases as a material with enhanced radioactivity. Accordingly, the use of coal ashes in lightweight concrete must comply with requirements of international recommendations and national legislations. Over the past decade, a series of studies were performed at the Ariel University Center of Samaria (Ariel, Israel) in search for optimum solutions for the use of coal ashes (both fly and bottom ashes) in the lightweight concrete technology. These studies included investigations of scientific and engineering issues related to the radiological and engineering aspects of the utilization of coal ashes in the building industry, as described in this paper. Special attention was paid to a problem of producing ecologically-friendly concrete based on coal ashes. Our product contributes significantly to the advancement of material recirculation by using in addition to fly ash, also bottom ash. This significant by product of coal combustion is used at present predominantly for construction beddings, structural fills. Utilization of fly ash for concrete production contributes to the reduction of the potential damage to the environment that can be caused by the accumulation of coal ashes in piles and ponds near power stations. Bonding the ash particles (in safe quantities) with the cement in concrete articles and structures reduces the potential exposure of humans to internal radiation by avoiding the penetration of fine ash particles to human internal organs. In order to lower the radioactivity of concrete resulting from the use of coal ashes, we added to the concrete mixture calculated amounts of unprocessed crushed sand (UCS). This material is denser and is very low in radioactivity. UCS is a by-product of crushing limestone or dolomite in the process of crushed stone production at stone quarries. The Ariel University Center of Samaria (Ariel, Israel) performed during the last decade a series of studies, searching for optimum ways for the utilization of coal ashes in the production of economically friendly lightweight concrete. These studies were related to a variety of scientific and engineering issues as described in this presentation

  1. Microbiota of coal pit waste heaps of Chervonograd Mining Region after coal ash application

    Directory of Open Access Journals (Sweden)

    S. V. Kuzmishyna

    2015-02-01

    Full Text Available The aim of this work was to determine the impact of addition of coal ash from Dobrotvir TPP to waste heaps gangue (Chervonograd Mining Region on the number of different groups of microorganisms. 20 samples from three waste heaps, from the black and red gangue, under the mosses and from bare substrate and also from terrace, top and base of each waste heap, were selected. Waste heaps gangues with coal ash from Dobrotir TPP were mixed in vitro and left for 10 days. We used proportion of coal ash to gangue as 1 to 5. Microorganisms were grown in Petri dishes containing 20–30 ml agar medium and in 22 ml tubes at temperature of 28 °C. Microscopic fungi were revealed on Mash-agar; oligonitrophilic bacteria – on Ashby medium; actinomycetes – on Chapek’s medium; cellulose decomposing aerobic bacteria – on Hetchenson medium; colorless sulfur oxidizing bacteria: neutrophilic – on Beyerinck medium, acidophilic – on Silverman and Lundgren 9К medium. The acidity value of waste heaps gangue samples was determined by рН meter рН-150М. We observed that samples collected under the mosses had lower acidity compared to samples from the bare substrate. We also revealed lower acidity of the overburn red gangue than the acidity of freshly deposited black gangue. To sum up, application of coal ash resulted in lowering of acidity value among all samples under study. Coal ash addition led to increase in number of microscopic fungi cells compared to the appropriate control samples. The highest quantity of microscopic fungi (16.2 ± 0.79 х 105 CFU/g of gangue was revealed in sample from red rock of the main waste heap of Central Enrichment Plant (CEP. At the same time, we observed the highest cell number in the control sample under the mosses of “Nadija” coal pit waste heap, (6.1 ± 0.3 х 105 CFU/g of gangue. After coal ash addition, most samples featured 2–3 times higher quantities of colorless sulfur-oxidizing neutrophilic bacteria cells. The highest cell number of these microorganisms was observed in sample under the mosses of “Vizejska” coal pit waste heap. The same dominance of oligonitrophilic bacteria cell number in experimental samples over control samples was indicated. The highest cell quantity was recorded for the sample under the moss from terrace of waste heap of “Nadija” coal pit (25.6 ± 1.3 х 104 CFU/g of gangue and in sample from red rock of CEP main waste heap (21.1 ± 1.1 х 104 CFU/g of gangue, being 43.3 and 31.7 times higher than the appropriate controls. Meanwhile, the number of colorless sulfur-oxidizing acidophilic bacteria in control samples was higher than that after coal ash addition, particularly, on the bare substrate samples from the base and terrace of waste heap of “Nadija” coal pit. Higher cell number in control samples without coal ash was typical for actinomycetes with the greatest difference (8.6 times before and after coal ash addition in a sample from red rock of CEP main waste heap. We detected 2 times lower number of cellulose-decomposing aerobic bacteria in the majority of experimental samples compared to appropriate control samples under study. In that way, we noticed that addition of coal ash from Dobrotvir TPP to waste heaps gangue (in proportion of coal ash to gangue as 1 to 5 caused reduction of substrate acidity value. Under these conditions the number of colorless sulfur-oxidizing neutrophilic bacteria, oligonitrophilic bacteria and microscopic fungi cells increased. But on the other hand, coal ash addition resulted in lowering of the number of colorless sulfur-oxidizing acidophilic bacteria, actinomycetes, and cellulose-decomposing aerobic bacteria cells.

  2. Natural Radionuclides in Slag/Ash Pile from Coal-Fired Power Plant Plomin

    International Nuclear Information System (INIS)

    Full text: The coal slag/ash pile contains about one million tons of different (bottom ash, filter ash, gypsum) waste material deposited in vicinity of Plomin coal-fired power plant. Activities of 40K, 228Ra, 226Ra and 238U in materials deposited on slag/ash pile as well as in used coals were occasionally measured during past more than two and half decades of Plomin coal-fired plant operation. The radionuclides content in deposited bottom and filter ash material are related with radionuclide activities and mineral matter fraction in coals used. Up to the middle of nineties, the majority of coal used was anthracite from Istrian local mines. In that period, deposited waste material was characterised with relatively high 226Ra and 238U activities while potassium and thorium content was very low. When Istrian coal has been completely substituted with imported coal, uranium series radionuclide concentrations in deposited waste materials decreased significantly. Meanwhile, potassium and thorium activities in slag/ash pile material increased. It seems that slag/ash pile material generated in the last several years of Plomin coal-fired power plant operation could be generally used in cement industry without any special restriction. (author)

  3. Unburned carbon in ash prediction in pulverized coal utility boilers

    Energy Technology Data Exchange (ETDEWEB)

    Ranz, J.P.; Pelet, I.A. [Centre of Research of Energy Resources and Consumption (CIRCE) (Spain)

    2008-07-01

    Unburned char particles that leave the furnace represent a heat loss in the combustion process, reducing the thermal efficiency of the unit. Since the price of coal is the higher variable cost in the plant, a little saving in its cost may imply a significant reduction in the power plant expenditure. The main goal of this work was to develop an unburned carbon prediction system, that provides an on-line estimation of carbon in ash losses for a given operating condition in a utility boiler. At the same time, a system with such characteristics may allow the plant personnel to identify the source of an increase in the carbon in ash level or to look for the most suitable conditions to minimize this loss. The final system combines different predictive techniques, that are generally used isolated, allowing us to unify the following advantages within the same system: fluid dynamics and heat transfer from CFD codes, detailed chemical kinetics from advanced combustion models and reduced computing cost and interpolation capabilities from neural networks. The development and validation of the predictive system was carried out using standard plant instrumentation measurements gathered at Lamarmora ASM Brescia power station during January-March 2005 for three different coals. 14 refs., 5 figs., 2 tabs.

  4. Uranium content in coal and fly ash samples

    International Nuclear Information System (INIS)

    In the present study, we have measured the U-content in coal samples of different collieries used as fuel in Thermal Power Plant, Kasimpur (U.P.) and in the fly ash collected from there. The samples were ground very finely and sieved through a 100 mesh sieve. The sample powder and methyl cellulose powder (a binder free from uranium contamination) were mixed in the ratio 1:2 by weight. Thin pellets of this mixture (∼ 1.3 cm dia) was made by a hydraulic tablet making machine. These pellets were sandwiched between a pair of washed, cleaned and dried plastic track detector (Makrofol KG). These pellets along with a pellet of standard glass of known U-content were irradiated with a thermal neutron dose of 1015 (nvt) in the 'APSARA' reactor at Bhabha Atomic Research Centre, Bombay. After irradiation the detectors were separated and etched in 6.25M KOH at 80 C for 20 minutes. The resulting tracks were counted. The U-content in coal shows a variation of 1.07 to 6.67 ppm in uniform distribution and 26.82 to 46.74 ppm in non-uniform distribution. In fly ash the U-content varies from 6.83 to 9.48 ppm in uniform and from 51.73 to 64.50 ppm in non-uniform distribution. (author). 5 refs., 2 tabs

  5. Investigation of the coal fly ashes using IR spectroscopy

    Science.gov (United States)

    Mozgawa, W.; Krl, M.; Dyczek, J.; Deja, J.

    2014-11-01

    The results of FT-IR spectroscopic studies of coal fly ashes, originated from various polish power plants are reported. The results of MIR investigations were compared to the X-ray diffraction (XRD) measurements and chemical analyses. They are mainly composed of silica, alumina and lime. The infrared spectrum in the middle range can be used to describe both the structure of phases present in the fly ash and to identify the characteristic elements of the individual components of ash. The results indicate that the amount of aluminosilicate and its Si/Al ratio induce a shift in the T-O stretching band appearing at 950-1100 cm-1. Moreover, FWHM of these bands indicates the participation of the crystalline phase relative to amorphous. The presence of carbonate phases generates substantial changes in the 1450-1400 cm-1 area of the spectra. The presence of such phases as anhydrite, mullite or illite has also been established on the basis of IR spectra.

  6. 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.

  7. 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.

  8. Kinetics of Alkaline Activation of Slag and Fly ash-Slag Systems

    Science.gov (United States)

    Chithiraputhiran, Sundara Raman

    Alkali-activated aluminosilicates, commonly known as "geopolymers", are being increasingly studied as a potential replacement for Portland cement. These binders use an alkaline activator, typically alkali silicates, alkali hydroxides or a combination of both along with a silica-and-alumina rich material, such as fly ash or slag, to form a final product with properties comparable to or better than those of ordinary Portland cement. The kinetics of alkali activation is highly dependent on the chemical composition of the binder material and the activator concentration. The influence of binder composition (slag, fly ash or both), different levels of alkalinity, expressed using the ratios of Na2O-to-binders (n) and activator SiO2-to-Na2O ratios (Ms), on the early age behavior in sodium silicate solution (waterglass) activated fly ash-slag blended systems is discussed in this thesis. Optimal binder composition and the n values are selected based on the setting times. Higher activator alkalinity (n value) is required when the amount of slag in the fly ash-slag blended mixtures is reduced. Isothermal calorimetry is performed to evaluate the early age hydration process and to understand the reaction kinetics of the alkali activated systems. The differences in the calorimetric signatures between waterglass activated slag and fly ash-slag blends facilitate an understanding of the impact of the binder composition on the reaction rates. Kinetic modeling is used to quantify the differences in reaction kinetics using the Exponential as well as the Knudsen method. The influence of temperature on the reaction kinetics of activated slag and fly ash-slag blends based on the hydration parameters are discussed. Very high compressive strengths can be obtained both at early ages as well as later ages (more than 70 MPa) with waterglass activated slag mortars. Compressive strength decreases with the increase in the fly ash content. A qualitative evidence of leaching is presented through the electrical conductivity changes in the saturating solution. The impact of leaching and the strength loss is found to be generally higher for the mixtures made using a higher activator Ms and a higher n value. Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR) is used to obtain information about the reaction products.

  9. 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. Special projects provide an opportunity for non-CARRC members to sponsor specific research or technology transfer consistent with CARRC goals. This report covers CARRC activities from January 2007 through March 2009. These activities have been reported in CARRC Annual Reports and in member meetings over the past 2 years. CARRC continues to work with industry and various government agencies with its research, development, demonstration, and promotional activities nearing completion at the time of submission of this report. CARRC expects to continue its service to the coal ash industry in 2009 and beyond to work toward the common goal of advancing coal ash utilization by solving CCP-related technical issues and promoting the environmentally safe, technically sound, and economically viable management of these complex and changing materials.

  10. 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

  11. 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 Mining Basin. Natural radionuclides content in fly ash is compared to the combusted coal some 3 - 4 times higher and may present a limitation for applying ash in the construction industry. In view of the above, and considering the construction industry interests in using the Nikola Tesla B TPP ash, regular investigations of the natural radionuclides content in ash created in the thermal power plants should be carried out, together with the Kolubara Mining Basin coal combusted by the Nikola Tesla B TPP and other PE EPS thermal power plants. The current Kolubara Mining Basin coal characteristics investigation programme should be supplemented by the natural radionuclides content of the uranium (238U, 226Ra and thorium series (232Th and potassium 40 (40K.

  12. Coal fly ash and synthetic coal fly ash aggregates as reactive media to remove zinc from aqueous solutions.

    Science.gov (United States)

    Hong, Jung-Ki; Jo, Ho Young; Yun, Seong-Taek

    2009-05-15

    Coal fly ash (CF) and synthetic coal fly ash aggregates (SCFAs) were evaluated as low-cost reactive media for the remediation of groundwater contaminated with Zn. The SCFAs were prepared by mixing CF, sodium silicate, and deionized (DI) water. Serial batch kinetic and static tests were conducted on both CF and SCFAs, under various conditions (i.e., pH, initial Zn concentration, reaction time, and solid dosage), using Zn(NO(3))(2).6H(2)O solutions. Serial column tests were also conducted on both CF and SCFAs. The final rather than the initial pH of the solution had a greater effect on the removal of Zn. At pH>7.0, the removal of Zn was due to precipitation, whereas at <7.0, the removal of Zn was due to adsorption onto the reactive media. The removal of Zn increased with increasing dosage of the reactive medium and decreasing initial Zn concentration. The results of the column and batch tests were comparable. Preferential flow paths were observed with CF, but not SCFA. The hydraulic conductivity of CF was more significantly decreased than that of SCFA with increasing dry density of the specimen. PMID:18805638

  13. 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

  14. Measurement of combustion rate of coal char and unburned carbon contained in coal fly ash by thermobalance

    Energy Technology Data Exchange (ETDEWEB)

    Hasatani, M.; Arai, N.; Naruse, I.; Kondo, K. (Nagoya University, Nagoya (Japan). Dept. of Chemical Engineering)

    1989-01-01

    The respective combustion rates of the chars produced from Kangra and Newlands coals and the coal fly ashes emitted from a pulverized coal combustor and from a fluidized coal combustor were measured by a thermobalance with an infrared heating system. For each sample, the rate-expression in the chemical reaction controlling rate regime was manifested, and the Arrhenius plots of the rate-constants obtained were compared with the plots quoted from the references. 10 refs., 8 figs., 2 tabs.

  15. Emission Characteristics of NOx and Unburned Carbon in Fly Ash of Sub-bituminous Coal Combustion

    Science.gov (United States)

    Ikeda, Michitaka; Kozai, Yukitoshi; Makino, Hisao

    Sub-bituminous coal is considered to be one substitute fuel for bituminous coal. Since sub-bituminous coal contains more than 20% moisture, there are some problems with its utilization, such as a decrease in combustibility, high NOx emission and so on. This report describes the emission characteristics of NOx and unburned carbon in fly ash of sub-bituminous coal combustion through the use of a pulverized coal combustion test furnace. On the sub-bituminous coal combustion, ignition at the burner exit worsened and the combustion flame became diffused. Then, both NOx emission and the unburned carbon concentration in fly ash became high. In order to keep stable combustion and to form an effective NOx reduction flame, the swirl vane angle of secondary air was reduced and the Air/Coal ratio was lowered. As a result, the combustion flame became moderate, and both NOx emission and unburned carbon concentration in fly ash could be reduced.

  16. Uranium content of coal ashes from Southern Brazil coal fueled power stations, by the fission track registration technique

    International Nuclear Information System (INIS)

    The feasibility of the application of the fission track registration technique for the determination of uranium in coal ashes was shown. The wet method was employed using as detector the Makrofol KG=10 μm, manufactured by Bayer. The coal ashes were originated from coal-fueled power stations localized in Southern Brazil. The results obtained ranged from 10 to 27 mg U/kg. Since the total error variation was from 18,4% to 23,8%, the method used was considered excellent. The determination of the uranium content in coal ashes is of considerable interest in environmental control in power stations, in their vicinity and wherever these ashes are used or stored. The technique used is the work proved to be very appropriate for the purpose aimed at. (Author)

  17. 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

  18. Application of dry separative methods for decreasing content the residues unburned coal and separation Fe from black coal flies ash

    Directory of Open Access Journals (Sweden)

    František Kaľavský

    2008-06-01

    Full Text Available Main obstacle using of fly ashes in building, that is its main consumer, is the residue of unburned coal; it is expressed of loss onignition - LOI. In present, the valid STN and EU standard limits the content of LOI to 3 – 5 %, in national conditions maximum 7 %.Application of processing technologies also has to assure utilization of fly ash that provides a possibility of complex utilizationof individual products obtained by modification.By means of corona separation, based on different conductivity of individual fly ash elements, it is possible to separate unburnedcoal particles. The fly ash sample from black coal burning in melting boiler that was deposited on fly ash deposit, content of LOIof dielectric particle 6,45 % at 61 % weight yield was achieved. In the samples taken from dry taking of fly ash the non-conductingproduct contained 7,72 % of LOI at 73 % of weight yield.

  19. Comparison of fly ash properties from Afsin-Elbistan coal basin, Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Ural, Suphi [Department of Mining Engineering, Cukurova University, 01330 Adana (Turkey)]. E-mail: suralp@mail.cu.edu.tr

    2005-03-17

    Afsin-Elbistan (AE) coal fly ashes obtained by burning coal samples from top, middle and bottom sections of the AE coal seam were characterized and their properties were compared. Chemical analysis of the AE coal fly ashes showed that they are mainly composed of CaO, SiO{sub 2}, Fe{sub 2}O{sub 3} and Al{sub 2}O{sub 3}. Quantitative X-ray diffraction (XRD) analyses were carried out using an interactive data processing system (SIROQUANT{sup TM}) based on Rietveld interpretation methods. Lime is found in all the samples, ranging from around 7% to just over 38%. Amorphous contents of fly ashes are ranged between 19% and 25%. Different types of AE fly ashes revealed that bottom section coal fly ash is very similar to Class F, while medium and top section coal fly ashes are close to Class C and they might be used as mineral admixture in concrete. But also they do not comply with any of the standard. The results presented here show new possibilities for AE coal fly ashes in a wide range of fields, resulting in great advantages in waste minimization, as well as, resources conservation.

  20. Design and construction of gamma transmission gauge for determination of the ash content in coal

    International Nuclear Information System (INIS)

    More than two years research work on design of a dual energy ?-ray transmission gauge is reviewed in this paper. The gauge after construction will be to install in a large coal industry named Kerman District Coal Mines (KDCM). KDCM consists of several coal mines, so that, coal transported on a conveyor belt may be a non-homogenious mixture from one or more mines. Therefore, prior to gauge design, primary investigation is done to identify and evaluate the relationship between the mass absorption coefficient (?-bar) and ash percent of coal for the mixture running on the belt. Results of investigation shows that, coal mixture calibration curve cannot be used accurately for ash estimation in coal of individual mines and, essentially, gauge may work to determine the ash percent with some limitations in this particular region. Therefore, design of gauge was carried out in the laboratory and after setting up, primary experimental calibration curve for the gauge is obtained. The r.m.s. difference between gauge ash and chemical assay is 1.17 wt% ash, for ash in the range of 32-44 (wt%). It is programmed for future to complete and improve the gauge to be able for on-line ash determinations. (author). 5 refs, 7 figs, 2 tabs

  1. 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 ID assays. Results suggest that ID methods can be used to enhance knowledge of trace element behaviour in fresh and weathered fly ash

  2. Bench-scale synthesis of zeolite A from subbituminous coal ashes with high crystalline silica content

    Energy Technology Data Exchange (ETDEWEB)

    Chareonpanich, M.; Jullaphan, O.; Tang, C. [Kasetsart University, Bangkok (Thailand). Dept. of Chemical Engineering

    2011-01-15

    In this present work, fly ash and bottom ash with high crystalline silica content were obtained from the coal-fired boilers within the paper industries in Thailand. These coal ashes were used as the basic raw materials for synthetic zeolite production. The crystal type and crystallinity, specific surface area and pore size, and textural properties of zeolite products were characterized by using X-ray diffraction spectroscopy (XRD), N{sub 2} sorption analysis, and Scanning Electron Microscopy (SEM), respectively. It was found that sodalite octahydrate was selectively formed via the direct conventional (one-step) synthesis, whereas through a two-step, sodium silicate preparation and consecutive zeolite A synthesis process, 94 and 72 wt.% zeolite A products could be produced from the fly ash and bottom ash, respectively. The cation-exchange capacity (CEC) of fly ash and bottom ash-derived zeolite A products were closely similar to that of the commercial grade zeolite A.

  3. Coal ash fusion temperatures -- New characterization techniques, and associations with phase equilibria

    Energy Technology Data Exchange (ETDEWEB)

    Wall, T.F.; Gupta, R.P.; Gupta, S. [Univ. of Newcastle, New South Wales (Australia). Dept. of Chemical Engineering; Creelman, R.A. [R.A. Creelman and Associates, Epping, New South Wales (Australia); Coin, C. [ACIRL Ipswich, Booval, Queensland (Australia); Lowe, A. [Pacific Power, Sydney, New South Wales (Australia)

    1996-12-31

    The well-documented shortcomings of the standard technique for estimating the fusion temperature of coal ash are its subjective nature and poor accuracy. Alternative measurements based on the shrinkage and electrical conductivity of heating samples are therefore examined with laboratory ash prepared at about 800 C in crucibles, as well as combustion ash sampled from power stations. Sensitive shrinkage measurements indicate temperatures of rapid change which correspond to the formation of liquid phases that can be identified on ternary phase diagrams. The existence and extent of formation of these phases, as quantified by the magnitude of peaks in the test, provide alternative ash fusion temperatures. The peaks from laboratory ashes and corresponding combustion ashes derived from the same coals show clear differences which may be related to the evaporation of potassium during combustion and the reactions of the mineral residues to form combustion ash.

  4. Dilithium dialuminium trisilicate Crystalline Phase Prepared from Coal Fly Ash

    Science.gov (United States)

    Yao, Zhitong; Xia, Meisheng; Ye, Ying

    2012-06-01

    The dilithium dialuminium trisilicate phase Li2Al2Si3O10 was prepared using coal fly ash and lithium hydroxide monohydrate LiOHH2O as precursors. The influences of various preparation conditions on Li2Al2Si3O10 forming were investigated. The results showed that the optimum additive amount of LiOHH2O was about 20%. The onset of calcining temperature and time was identified as 980 C and 1 h, respectively. XRD analysis indicated that the content of Li2Al2Si3O10 phase increased at the expense of quartz and mullite, with calcining temperatures increasing and time extending. SEM observation revealed that the calcined samples were drastically interlocked together with the prolonging of time. The obtained Li2Al2Si3O10 phase was well crystallized and with small grain size.

  5. Main characteristics of the radioactive enrichment in ashes produced in coal-fired power stations

    International Nuclear Information System (INIS)

    Under contract with the Spain's ''Nuclear Safety Council'', a study is being conducted of the nation's largest nominal output coal-fired power stations. Its purpose is to assess the radiological impact on workers and local populations due to this source of NORM activity. One of the aspects of particular interest is the study of the radioactive enrichment in the combustion wastes relative to the different coals used as fuel (usually local bituminous coal or lignite, or imported coal). These wastes consist of fly ash (mostly fine particles collected in electrostatic precipitators), and bottom ash (larger in size, and collected wet or dry in hoppers below the boilers). In general terms, the enrichment factors measured were between 2 and 18 for the radionuclides 40K, 226Ra, 232Th, and 210Po. The magnitude of this enrichment factor depended mainly on the ash content of each coal, and hence on the type of coal used as fuel and the specific operation cycle in the different power stations. For the radionuclides 40K, 226Ra, and 232Th, the enrichment was relatively similar in value in the fly and bottom ashes produced by the different types of coal used in the power stations studied. For 210Po, however, as was expected, the enrichment was much greater in the fly ash than in the bottom ash for each coal analyzed. (author)

  6. Main characteristics of the radioactive enrichment in ashes produced in coal-fired power stations

    International Nuclear Information System (INIS)

    Under contract with the Spain's 'Nuclear Safety Council', a study is being conducted of the nation's largest nominal output coal-fired power stations. Its purpose is to assess the radiological impact on workers and local populations due to this source of NORM activity. One of the aspects of particular interest is the study of the radioactive enrichment in the combustion wastes relative to the different coals used as fuel (usually local bituminous coal or lignite, or imported coal). These wastes consist of fly ash (mostly fine particles collected in electrostatic precipitators), and bottom ash (larger in size, and collected wet or dry in hoppers below the boilers). In general terms, the enrichment factors measured were between 2 and 18 for the radionuclides 40K, 226Ra, 232Th, and 210Po. The magnitude of this enrichment factor depended mainly on the ash content of each coal, and hence on the type of coal used as fuel and the specific operation cycle in the different power stations. For the radionuclides 40K, 226Ra, and 232Th, the enrichment was relatively similar in value in the fly and bottom ashes produced by the different types of coal used in the power stations studied. For 210Po, however, as was expected, the enrichment was much greater in the fly ash than in the bottom ash for each coal analyzed. (author)

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

    DEFF Research Database (Denmark)

    Zheng, Yuanjing; Jensen, Peter Arendt; Jensen, Anker Degn; Sander, Bo; Junker, Helle

    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 flow...... reactor experiments with co-firing of coal and straw, making mineral and alkali vapor laboratory reactor experiments and by developing a model of KCl reaction with kaolin. The results include correlations that can be used to estimate the speciation of potassium in the fly ash when co-firing straw and...

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

    DEFF Research Database (Denmark)

    Arvelakis, Stelios; Frandsen, Flemming

    2010-01-01

    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...... 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....

  9. 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. PMID:26093343

  10. Influence of Chemical Composition on the Electrical Resistivity of Fly Ash Generated from Indian Coal Based Thermal Power Plants

    OpenAIRE

    Syed Javid Ahmad Andrabi; Avinash Chandra; Mohd. Aslam; Hassan, I A

    2013-01-01

    Electrostatic Precipitators (ESP) are control devices widely used for collection of fly ash in Indian coal based thermal power plants. The design, performance, sizing, collection and operation of ESP depend largely on the properties and quality of the coal burned and the fly ash generated in the boilers. This study presents the influence of fly ash composition on the resistivity of Indian fly ash generated from coal based power plants, which is one of the critical parameter required to make a...

  11. Application of coal ash to civil engineering material. Interim report(3) Test road using coal ash (coarse particle ash available), (Construction report, 1). Sekitanbai no dobokuzairyo eno riyo. Chukanhokoku(3)

    Energy Technology Data Exchange (ETDEWEB)

    Igarashi, Kazuhiko; Tobana, Kosaku; Fujita, Keiichi

    1982-06-01

    This paper summarizes the test result of physical properties of coal ash, the construction work of test road applying coal ash (coarse particle ash available) as the pavement flux, roadbed material and frost heaving inhibitor material to the ash landfill road in the site of Takikawa Power Plant, the result of field test carried out or the same time of the construction of the test road and the measurements by the buried instruments. No crack on the surface of the road has been observed so far and no effects frost heaving or subsidence have been found. (6 refs, 43 figs, 44 tabs, 29 photos)

  12. Water Retention Characteristics of Porous Ceramics Produced from Waste Diatomite and Coal Fly Ash

    OpenAIRE

    Kae-Long Lin; Ju-Ying Lan

    2013-01-01

    This study examines potential waste diatomite and coal fly ash reuse to prepare water absorption and retain porous ceramics. The operating conditions are constant pressure (5 MPa), sintering temperature (1000-1270°C), sintering time (2 h), waste diatomite containing coal fly ash at different proportions (0-20%), respectively. The porous ceramic samples containing coal fly ash show low thermal conductivity properties (0.278-0.349 W/mK), probably owing to the more pores than those in the concre...

  13. Mechanism of alkalinity lowering and chemical equilibrium model of high fly ash silica fume cement

    International Nuclear Information System (INIS)

    The mechanism of alkalinity lowering of a High Fly ash Silica fume Cement (HFSC) under liquid/solid ratio conditions where the pH is largely controlled by the soluble alkali components (Region I) has been studied. This mechanism was incorporated in the chemical equilibrium model of HFSC. As a result, it is suggested that the dissolution and precipitation behavior of SO42- partially contributes to alkalinity lowering of HFSC in Region I. A chemical equilibrium model of HFSC incorporating alkali (Na, K) adsorption, which was presumed as another contributing factor of the alkalinity lowering effect, was also developed, and an HFSC immersion experiment was analyzed using the model. The results of the developed model showed good agreement with the experiment results. From the above results, it was concluded that the alkalinity lowering of HFSC in Region I was attributed to both the dissolution and precipitation behavior of SO42- and alkali adsorption, in addition to the absence of Ca(OH)2. A chemical equilibrium model of HFSC incorporating alkali and SO42- adsorption was also proposed. (author)

  14. Reduction of metal leaching in brown coal fly ash using geopolymers.

    Science.gov (United States)

    Bankowski, P; Zou, L; Hodges, R

    2004-10-18

    Current regulations classify fly ash as a prescribed waste and prohibit its disposal in regular landfill. Treatment of the fly ash can reduce the leach rate of metals, and allow it to be disposed in less prescribed landfill. A geopolymer matrix was investigated as a potential stabilisation method for brown coal fly ash. Precipitator fly ash was obtained from electrostatic precipitators and leached fly ash was collected from ash disposal ponds, and leaching tests were conducted on both types of geopolymer stabilised fly ashes. The ratio of fly ash to geopolymer was varied to determine the effects of different compositions on leaching rates. Fourteen metals and heavy metals were targeted during the leaching tests and the results indicate that a geopolymer is effective at reducing the leach rates of many metals from the fly ash, such as calcium, arsenic, selenium, strontium and barium. The major element leachate concentrations obtained from leached fly ash were in general lower than that of precipitator fly ash. Conversely, heavy metal leachate concentrations were lower in precipitator fly ash than leached pond fly ash. The maximum addition of fly ash to this geopolymer was found to be 60wt% for fly ash obtained from the electrostatic precipitators and 70wt% for fly ash obtained from ash disposal ponds. The formation of geopolymer in the presence of fly ash was studied using 29Si MAS-NMR and showed that a geopolymer matrix was formed. X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) imaging showed the interaction of the fly ash with the geopolymer, which was related to the leachate data and also the maximum percentage fly ash addition. PMID:15511575

  15. Reduction of metal leaching in brown coal fly ash using geopolymers

    International Nuclear Information System (INIS)

    Current regulations classify fly ash as a prescribed waste and prohibit its disposal in regular landfill. Treatment of the fly ash can reduce the leach rate of metals, and allow it to be disposed in less prescribed landfill. A geopolymer matrix was investigated as a potential stabilisation method for brown coal fly ash. Precipitator fly ash was obtained from electrostatic precipitators and leached fly ash was collected from ash disposal ponds, and leaching tests were conducted on both types of geopolymer stabilised fly ashes. The ratio of fly ash to geopolymer was varied to determine the effects of different compositions on leaching rates. Fourteen metals and heavy metals were targeted during the leaching tests and the results indicate that a geopolymer is effective at reducing the leach rates of many metals from the fly ash, such as calcium, arsenic, selenium, strontium and barium. The major element leachate concentrations obtained from leached fly ash were in general lower than that of precipitator fly ash. Conversely, heavy metal leachate concentrations were lower in precipitator fly ash than leached pond fly ash. The maximum addition of fly ash to this geopolymer was found to be 60 wt% for fly ash obtained from the electrostatic precipitators and 70 wt% for fly ash obtained from ash disposal ponds. The formation of geopolymer in the presence of fly ash was studied using 29Si MAS-NMR and showed that a geopolymer matrix was formed. X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) imaging showed the interaction of the fly ash with the geopolymer, which was related to the leachate data and also the maximum percentage fly ash addition

  16. Durable power performance of a direct ash-free coal fuel cell

    International Nuclear Information System (INIS)

    Highlights: •Investigation of a direct carbon fuel cell (DCFC) using raw and ash-free coal fuels. •Enhanced durability of a DCFC performance using ash-free coal. •Comprehensive characterization of physicochemical properties of coals. •Development of an optimal design of the configuration of DCFC reactor. -- Abstract: We have investigated the comparable performance of raw and ash-free coal in the operation of a direct carbon fuel cell (DCFC). The various structural and morphological analyses using SEM, TEM, EDX, XPS, XRD, and TGA are carried out to study the distinct physicochemical properties of coals. Due to contained volatile organic compounds, raw coal generates about a two-fold higher fuel cell performance compare to ash-free coal below a reaction temperature of 750 °C. However, over a cell temperature of 900 °C, both of them reach a similar power density of 170 mW cm−2. In the long-term operation of a DCFC, we observe a distinctly more durable power performance using ash-free coal than that of raw coal

  17. 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.

  18. 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)

  19. Modeling and Prediction of Coal Ash Fusion Temperature based on BP Neural Network

    Directory of Open Access Journals (Sweden)

    Miao Suzhen

    2016-01-01

    Full Text Available Coal ash is the residual generated from combustion of coal. The ash fusion temperature (AFT of coal gives detail information on the suitability of a coal source for gasification procedures, and specifically to which extent ash agglomeration or clinkering is likely to occur within the gasifier. To investigate the contribution of oxides in coal ash to AFT, data of coal ash chemical compositions and Softening Temperature (ST in different regions of China were collected in this work and a BP neural network model was established by XD-APC PLATFORM. In the BP model, the inputs were the ash compositions and the output was the ST. In addition, the ash fusion temperature prediction model was obtained by industrial data and the model was generalized by different industrial data. Compared to empirical formulas, the BP neural network obtained better results. By different tests, the best result and the best configurations for the model were obtained: hidden layer nodes of the BP network was setted as three, the component contents (SiO2, Al2O3, Fe2O3, CaO, MgO were used as inputs and ST was used as output of the model.

  20. Relations between ash-fusion characteristics and depositional environment for an Appalachian Basin coal seam

    International Nuclear Information System (INIS)

    This paper reports that ash-fusion characteristics of the Lower Kittanning seam (western Pennsylvania) can be related to environment of deposition. Non-slagging coals (coals with ashes that have ash-fusion temperatures [AFTs] in excess of 2,600 degrees F) are associated with fresh-water environments that occur toward the margins of the basin. Slagging coals (coals with ashes that melt at temperatures less than 2,000 degrees F) occur in the central part of the basin, in areas overlain by shales that have been interpreted to have formed in a brackish environment. Trend-surface analysis indicates that whereas strong basinal trends do exist, locally variability can modify regional trends. High ash-fusion coals are associated with high clay (primarily kaolinite) contents, whereas low-fusion coals are associated with high pyrite and marcasite (and to a lesser extent, siderite) contents. Bivariate analysis of these data shows highly significant negative correlations between AFT and Fe2O3, pyrite, and siderite. Positive correlations exist between AFT and SiO2, Al2O3, TiO2, MgO, and K2O. Illite and kaolinite also correlate positively with AFT. An understanding of the oxide and mineral composition of the ash and the depositional environment of the peat can therefore be useful in the prediction of ash-fusion characteristics

  1. Unsubstituted polyaromatic hydrocarbons (PAH's) in extracts of coal fly ash from the fly ash test cell in Montour, Pennsylvania

    International Nuclear Information System (INIS)

    Isotope Dilution Mass Spectrometry (IDMS) was used to identify and to quantify trace amounts of selected, unsubstituted polyaromatic hydrocarbons (PAH's) present in extracts of coal fly ash from the solid waste disposal test cell at Montour, Pennsylvania. Isotope dilution experiments using deuterated analogs of polyaromatic hydrocarbons demonstrated that the concentrations of benzo[a]pyrene and anthracene were lower than 1 ng/g of fly ash. Isotope dilution experiments demonstrated that benzo[a]pyrene could be detected at concentrations as high as 1 ng/g when an isotopic carrier was used at a concentration of 125 ng/g in the analytical method. Maximum concentrations of fluorene, fluoranthene, pyrene and chrysene were conservatively estimated to be 3 ng/g of fly ash, using a 95 percent confidence interval based on analytical precision of ±1 ng/g of fly ash. Concentrations of phenanthrene were found to range from 6 to 38 ng/g of fly ash with a mean concentration of 14 ng/g of fly ash. Two sources of phenanthrene were speculated: incomplete combustion of phenanthrene in the coal furnace and addition of phenanthrene to the fly ash after collection by electrostatic precipitators

  2. 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

  3. 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)

  4. 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

  5. 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.

  6. Radioactive substances in fly ash from coal-fired power plants

    International Nuclear Information System (INIS)

    Coal and fly ash samples from various German coal-fired power plants have been analyzed for 238U, 230Th, 226Ra, 210Pb, 228Th and 228Ra. It is shown, that the specific activity of the fly ash depends much more on the boiler type than on the specific activity of the coal. Characteristic differences were found between dry bottom furnaces and slag tap fired boilers. The enrichment of volatile substances in fly ash collected in the last electrostatic precipitator increases with the furnace temperature and is especially large, if the fly ash is recycled into the body of the furnace for granulation in slag tap fired boilers. Fly ash from such boilers contained up to 6 Bq/g (160 pCi/g) lead 210. (orig.)

  7. 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; Hurley, J.

    2006-01-01

    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...... cocombustion tests appeared to be somewhat different compared to that of the laboratory-prepared ash samples. The heated stage XRD data provide useful information regarding the reactions among the various ash compounds and the phase transformations during the heating and cooling of the ash samples and helped...

  8. EVALUATION OF ENVIRONMENTAL STRESS IMPOSED BY A COAL ASH EFFLUENT: WISCONSIN POWER PLANT IMPACT STUDY

    Science.gov (United States)

    Effluent discharged from the coal ash settling basin of the Columbia generating Station (Wisconsin) modified water chemistry (increased trace metal concentrations, suspended solids and dissolved materials) and substrate quality (precipitation of chemical floc) in the receiving st...

  9. Character of the Si and Al phases in coal gangue and its ash

    Energy Technology Data Exchange (ETDEWEB)

    Wang, L.H.; Zhao, P.D.; Li, G. [China University of Geoscience, Beijing (China)

    2009-07-01

    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{sub 2}O{sub 3} to SiO{sub 2} (i.e., Al{sub 2}O{sub 3} (mole) / SiO{sub 2} (mole)) is usually no more than 0.5 in most coal gangue fuel and its ashes. The kaolinite at about 984{sup o}C releases a large quantity of SiO{sub 2}, which makes calcine coal gangue more active than coal gangue itself. The relationship between the ratio Al{sub 2}O{sub 3} (mole)/SiO{sub 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.

  10. Mössbauer Studies of Thermal Power Plant Coal and Fly Ash

    Science.gov (United States)

    Taneja, S. P.

    Iron-57 Mössbauer spectroscopic studies were carried out at room temperature on samples of coal, slag (bottom ash) and mechanical ash collected from Bhatinda (India) thermal power plant. Hyperfine parameters such as isomer shift, quadrupole splitting and total internal magnetic field of 57Fe nuclei were used to characterize various iron-bearing minerals. The observed parameters indicate the presence of pyrite, siderite and ankerite in coal sample while magnetic fractions of mechanical ash and slag samples show the formation of hematite and Al-substituted magnesio-ferrite. The non-magnetic fraction of slag ash shows the dominance of Fe2+ phases while that of mechanical ash demonstrates the formation of both Fe2+ and Fe3+ phases. These findings are compared with Mössbauer and magnetic susceptibility studies on fly ash samples of Panipat (India) thermal power plant reported earlier.

  11. Activation analysis of pit-coal ash content with the use of isotopic fast neutron source

    International Nuclear Information System (INIS)

    The neutron activation techniques of coal ash determination are briefly reviewed and a new version of activation analysis using fast neutrons from 239Pu-Be source and basing on the reactions 28Si(n,p)28Al and 27Al(n,p)27Mg is proposed. 72 samples of pit-coals with ash content ranging from 3 to 40% were measured. The linear calibration function between ash content and both, 1.78 MeV and 0.84 MeV, γ-ray counts was obtained. The precision (0.94% ash for 17% ash content) and accuracy (1.4%ash for the whole range) were evaluated. Comparison of the results with those of fluorescent-scattering methods is made. (author)

  12. 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)

  13. 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...

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

    OpenAIRE

    Shi Yuanhao; Wang Jingcheng

    2015-01-01

    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...

  15. 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...

  16. EFFECT OF ASH DISPOSAL PONDS ON GROUNDWATER QUALITY AT A COAL-FIRED POWER PLANT

    Science.gov (United States)

    The impact of fly and bottom ash disposal ponds on groundwater quality was investigated at the coal-fired Columbia Power Plant at Portage, WI. Groundwater sampling was conducted utilizing a network of piezometers and multilevel wells located at various cross-sections of the ash d...

  17. Task 5.9 - use of coal ash in recycled plastics and composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Hassett, D.J.; Dockter, B.A.; Eylands, K.E.; Pflughoeft-Hassett, D.F.

    1995-07-01

    The goal of this research project by the Energy & Environmental Research Center (EERC) was to determine the potential for coal ash to serve as a {open_quote}functional filler{close_quotes} in plastics and other composite materials, with special emphasis on recycled plastics. The term functional filler is intended to indicate that the material added to the plastic does more than take up space and extend the use of the polymer. Determining the functional filler potential of ash was not the only intent of this project, since another prime objective was to find a use for materials currently considered waste. The term functional filler also opened a door to the use of cenospheres, which are currently marketed and for which there is sufficient market demand that they do not fit the category of a waste even though they are a product of coal combustion. Cenospheres, hollow spherical ash particles, were selected because of their unique properties. Although they currently have commercial applications, the unique nature of these materials make them an excellent candidate for use as a functional filler in composites. The ability to produce a commercially viable product from waste streams and a recycled material is a positive step toward reducing solid waste. The first task, since there are numerous types of coal ash, was to select suitable ash types for use in this project. Three basic types of material were selected: fly ash, a bottom ash, and a unique form of coal ash known as cenospheres.

  18. Task 5.9 use of coal ash in recycled plastics and composite materials. Topical report

    Energy Technology Data Exchange (ETDEWEB)

    Hassett, D.J.; Dockter, B.A.; Eylands, K.E.; Pflughoeft-Hassett, D.F.

    1995-11-01

    The goal of this research project by the Energy & Environmental Research Center (EERC) was to determine the potential for coal ash to serve as a {open_quotes}functional filler{close_quotes} in plastics and other composite materials, with special emphasis on recycled plastics. The term functional filler is intended to indicate that the material added to the plastic does more than take up space and extend the use of the polymer. Determining the functional filler potential of ash was not the only intent of this project, since another prime objective was to find a use for materials currently considered waste. The term functional filler also opened a door to the use of cenospheres, which are currently marketed and for which there is sufficient market demand that they do not fit the category of a waste even though they are a product of coal combustion. Cenospheres, hollow spherical ash particles, were selected because of their unique properties. Although they currently have commercial applications, the unique nature of these materials make them an excellent candidate for use as a functional filler in composites. The ability to produce a commercially viable product from waste streams and a recycled material is a positive step toward reducing solid waste. The first task, since there are numerous types of coal ash, was to select suitable ash types for use in this project. Three basic types of material were selected: fly ash, a bottom ash, and a unique form of coal ash known as cenospheres.

  19. MULTISTAGE CAUSTIC LEACHING DE-ASHING OF NIGERIAN LAFIA-OBI COAL

    Directory of Open Access Journals (Sweden)

    M. M. Chagga

    2011-12-01

    Full Text Available Fractions of the high ash Nigerian Lafia-Obi coal L250 ground to pass the 250 ?m sieve in threestages were subjected to proximate/ash composition analyses, hot aqueous leaching de-ashingwith water and sodium carbonate in multiple stages and in a H2O-Na2CO3-H2O sequence (withinitial solution homogenization. The results obtained showed that ash contents percent of 24.60,14.70 and 24.07 were obtained for fractions L-250(1, L-250(2 and L+250(2; respectively asagainst 32.55% in the as-received coal. The ash reductions obtained translate to overall averageash removal of about 38.66% at the 19.90% ash content of the concentrates blend at a good 1:20ratio of reagent to coal. The study also showed that a three stage leaching in the sequence H2ONa2CO3-H2O (HSH produced a higher leaching rate than Na2CO3-H2O-H2O (SHH. The ash contentof the concentrates blend at 19.90% is lower than 23.80% required for coal blends for Indianstandard coking practice, but higher than the maximum of 10% upper limit for the conventionalcokemaking practice. The reduction in ash content obtained at the atmospheric pressure treatmentof Lafia-Obi coal was found to compare favourably with that of a high pressure elevated temperatureautoclave leaching of an Illinois coal. Binary blend formulation between the prime coking westernCanada coal and Lafia-Obi coal as-leached showed that inclusion of 16.63% of the latter wasprobable and this translates to reduction in cost per ton of about $23.67. A successful upgrade ofthe leaching route derived to industrial scale will make Lafia-Obi coal available as a blend componentfor economical cokemaking.

  20. 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

  1. 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)

  2. Evaluation of the ecological risks to terrestrial wildlife associated with a coal ash disposal site

    International Nuclear Information System (INIS)

    Between 1955 and 1989, coal ash was deposited within an impounded watershed on the Oak Ridge Reservation, creating the 3.6 ha-Filled Coal Ash Pond (FCAP). The site has subsequently become vegetated, providing habitat for wildlife. To evaluate the risks that metals in the ash may pose to wildlife, ash, surface water, small mammal, and vegetation samples were collected and metal residues were determined. Metal concentrations, As and Se in particular, were elevated in ash, surface water, plant foliage, and small mammals relative to reference materials. Estimates of metal exposures received from food, water, and ash consumption were calculated for short-tailed shrews, white-footed mice, white-tailed deer, red fox, and red-tailed hawks. While shrews and mice were assumed to reside exclusively at and receive 100% exposure from the site, exposure experienced by deer, fox, and hawks was assumed to be proportional to the size of the site relative to their home range. Because deer had been observed to consume ash presumably for it's high sodium content, exposure experienced by deer consuming ash to meet sodium requirements was also estimated. To assess the risk of coal ash to wildlife, exposure estimates were compared to body-size adjusted toxicity data for each metal. These comparisons suggest that metals at the site may be detrimental to reproduction and survivorship of mice, shrews, deer and fox; hawks do not appear to be at risk

  3. Coal ash fusion temperatures - new characterization techniques and implications for slagging and fouling

    Energy Technology Data Exchange (ETDEWEB)

    Wall, T.F.; Creelman, R.A.; Gupta, R.P.; Gupta, S.K.; Coin, C.; Lowe, A. [University of Newcastle, Newcastle, NSW (Australia). CRC for Black Coal Utilisation

    1998-09-01

    The ash fusion test (AFT) is the accepted test for the propensity of coal ash to slag in the furnace. The well-documented shortcomings of this technique for estimating the fusion temperature of coal ash are its subjective nature and poor accuracy. Alternative measurements based on the shrinkage and electrical conductivity of heating samples are therefore examined here with laboratory ash prepared at about 800{degree}C in crucibles, as well as combustion ash samples from power stations. Sensitive shrinkage measurements indicate temperatures of rapid change which correspond to the formation of liquid phases that can be identified on ternary phase diagrams. The existence and extent of formation of these phases, as quantified by the magnitude of `peaks` in the test, provide alternative ash fusion temperatures. The peaks from laboratory ashes and corresponding combustion ashes derived from the same coals show clear differences which may be related to the evaporation of potassium during combustion and the reactions of the mineral residues to form combustion ash. A preliminary evaluation of data from nine power stations indicates that shrinkage measurements can provide an alternative approach to characterizing slagging. 15 refs., 9 figs., 2 tabs.

  4. Oxidation of Irkutsk sapropelite and brown coal by copper oxide in alkaline medium

    Energy Technology Data Exchange (ETDEWEB)

    Shishkov, V.F.; Randin, O.I.; Tuturina, V.V.

    1986-05-01

    Provides results of oxidizing breakdown of coal by copper oxide in alkaline medium for comparative investigations into humic and sapropelic coal structures. Breakdown products were studied with the help of nuclear magnetic resonance, gas-liquid chromatography and chromato-mass spectrometry. Finds considerable qualititative differences in chemical structure of sapropelites and brown coal. Uses samples of Budagovskii sapropelite and two types of brown coal from Azeisk and Mungunsk regions, preliminarily treated with alcohol-benzene mixture (1:1) ratio. Establishes that ether extracts of brown coal are characterized by a high number of badly resolved peaks particularly in the dicarboxylic acid region. 13 refs.

  5. 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 (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

  6. 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.)

  7. Brick manufacture with fly ash from Illinois coals. Technical report, March 1, 1995--May 31, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, R.E.; Dreher, G.; Moore, D.; Rostam-Abadi, M. [Illinois State Geological Survey, Urbana, IL (United States); Fiocchi, T. [Illinois Power Co. (United States); Swartz, D. [Colonial Brick Co. (United States)

    1995-12-31

    This investigation seeks to utilize fly ash in fired-clay products such as building and patio bricks, ceramic blocks, field and sewer tile, and flower pots. This goal is accomplished by 1) one or more plant-scale, 5000-brick tests of fly ash mixed with brick clays at the 20% or higher level; 2) a laboratory-scale study to measure the firing reactions of a range of compositions of clay and fly ash mixtures; 3) a preliminary study to evaluate the potential environmental and economic benefits of brick manufacture with fly ash. Bricks and feed materials will be tested for compliance with market specifications and for leachability of pollutants derived from fly ash. The laboratory study will combine ISGS databases, ICCI-supported characterization methods, and published information to improve predictions of the firing characteristics of Illinois fly ash and brick clay mixtures. Because identical methods are used to test clay firing and coal ash fusion, and because melting mechanisms are the same, improved coal ash fusion predictions are and additional expected result of this research. During this quarter we completed a manufacturing run at Colonial Brick Co. and began laboratory testing of samples from that run: clays, fly ash (from Illinois Power Company`s Wood River plant), and green and fired bricks, with and without fly ash. Bricks with 20% fly ash ``scummed`` during firing, and the fly ash failed to increase oxidation rate or water absorption, which were both expected. We obtained chemical and mineralogical analyses of the fireclays and shales at Colonial and Marseilles Brick Companies and began a series of selective dissolution analyses to more accurately determine the composition of the principal clay minerals in brick clays and the components in fly ash. We began related work of calculating normative mineralogical analyses for all clays and fly ashes that we sample.

  8. 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.

  9. A new rheometer for direct measurement of the flow properties of coal ash at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Tonmukayakul, N.; Nguyen, Q.D. [University of Adelaide, Adelaide, SA (Australia). Co-operative Research Centre for Clean Power from Lignite

    2002-03-01

    Development of more effective technologies of utilising low rank coals for power generation has been driven by a demand for higher efficiency, low capital costs and minimal environmental impacts. Fluidised bed systems are regarded as one of the more promising alternative technologies for power generation to overcome the disadvantage of the existing pulverised coal burning power generation plants for low rank coals. However, ash deposition and bed agglomeration are potential problems in fluidised bed processing of coals with high alkali and sulphur contents. In order to gain a better understanding of the mechanism of agglomeration in fluidised beds, a good knowledge of the rheological behaviour of coal ash deposits at high temperatures and under the processing conditions is necessary. Rheological characterisation of materials at high temperatures is difficult due to lack of standard instruments and reliable measurement techniques. We have recently developed a rheometer that has the capability of measuring the rheological properties of coal ash slag over a wide range of temperatures from 600 to 1300{sup o}C and under different processing atmospheres. In this paper the features of this unique instrument are described and the experimental technique developed for flow property measurement is outlined. Some typical measured rheological properties of coal ashes from different Australian low-rank coals are presented and discussed to illustrate the potential applicability of the rheometer for high-temperature rheological characterisation. Furthermore, by means of the experimental results obtained it is demonstrated that the alkali content of the coal ash plays a significant role in controlling the rheological characteristics of the ash deposit, which in turn has an important implication on agglomeration in fluidised bed combustion processes. 30 refs., 8 figs., 1 tab.

  10. Impact of coal and rice husk ash on the quality and chemistry of cement clinker

    International Nuclear Information System (INIS)

    Utilization of rice husk as an alternative fuel for coal is of interest due to its availability in huge quantities in Pakistan and also because its combustion is environmental pollution friendly as it generates much less SOX due to its much lower sulphur content (0.1-0.3%) compared to sulphur content in coals, particularly indeginous coals ranging from 0.6-14.8%. The purpose of present study was to examine the impact of co-firing of rice husk and coal on the quality of cement clinker so as to substitute expensive imported coal with the abundantly available cheaper rice husk to reduce the cost of production of the cement. For this investigation raw feed mix (mixture of limestone, clay, bauxite and laterite in predetermined proportions) used for cement manufacture was mixed with predetermined varying proportions of coal ash and rice husk ash and placed inside a muffle furnace at 1200 degree C - 1500 degree C i-e the temperatures prevailing in the industrial cement kilns, for various periods of time to obtain cement clinker. The quality and chemistry of cement clinker thus produced in the laboratory was experimentally studied to ensure the quality of cement clinker that would be obtained by co-firing of rice husk and coal in different proportions in industrial cement kilns as the coal ash and rice husk ash produced during combustion will get mixed with cement clinker in industrial kilns. The results indicated that there was decrease in the Lime Saturation Factor, Free Lime and Tricalcium Silicate (C3S) content and increase in the Dicalcium Silicate (C2S) content by increasing the rice husk ash and decreasing the coal ash proportion in the clinker. (author)

  11. 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.

  12. Mineral sequestration of CO2 by aqueous carbonation of coal combustion fly-ash

    International Nuclear Information System (INIS)

    The increasing CO2 concentration in the Earth's atmosphere, mainly caused by fossil fuel combustion, has led to concerns about global warming. A technology that could possibly contribute to reducing carbon dioxide emissions is the in-situ mineral sequestration (long term geological storage) or the ex-situ mineral sequestration (controlled industrial reactors) of CO2. In the present study, we propose to use coal combustion fly-ash, an industrial waste that contains about 4.1 wt.% of lime (CaO), to sequester carbon dioxide by aqueous carbonation. The carbonation reaction was carried out in two successive chemical reactions, first, the irreversible hydration of lime. CaO + H2O → Ca(OH)2 second, the spontaneous carbonation of calcium hydroxide suspension. Ca(OH)2 + CO2 → CaCO3 + H2O A significant CaO-CaCO3 chemical transformation (approximately 82% of carbonation efficiency) was estimated by pressure-mass balance after 2 h of reaction at 30 deg. C. In addition, the qualitative comparison of X-ray diffraction spectra for reactants and products revealed a complete CaO-CaCO3 conversion. The carbonation efficiency of CaO was independent on the initial pressure of CO2 (10, 20, 30 and 40 bar) and it was not significantly affected by reaction temperature (room temperature '20-25', 30 and 60 deg. C) and by fly-ash dose (50, 100, 150 g). The kinetic data demonstrated that the initial rate of CO2 transfer was enhanced by carbonation process for our experiments. The precipitate calcium carbonate was characterized by isolated micrometric particles and micrometric agglomerates of calcite (SEM observations). Finally, the geochemical modelling using PHREEQC software indicated that the final solutions (i.e. after reaction) are supersaturated with respect to calcium carbonate (0.7 ≤ saturation index ≤ 1.1). This experimental study demonstrates that 1 ton of fly-ash could sequester up to 26 kg of CO2, i.e. 38.18 ton of fly-ash per ton of CO2 sequestered. This confirms the possibility to use this alkaline residue for CO2 mitigation

  13. Mineral sequestration of CO(2) by aqueous carbonation of coal combustion fly-ash.

    Science.gov (United States)

    Montes-Hernandez, G; Prez-Lpez, R; Renard, F; Nieto, J M; Charlet, L

    2009-01-30

    The increasing CO(2) concentration in the Earth's atmosphere, mainly caused by fossil fuel combustion, has led to concerns about global warming. A technology that could possibly contribute to reducing carbon dioxide emissions is the in-situ mineral sequestration (long term geological storage) or the ex-situ mineral sequestration (controlled industrial reactors) of CO(2). In the present study, we propose to use coal combustion fly-ash, an industrial waste that contains about 4.1 wt.% of lime (CaO), to sequester carbon dioxide by aqueous carbonation. The carbonation reaction was carried out in two successive chemical reactions, first, the irreversible hydration of lime. second, the spontaneous carbonation of calcium hydroxide suspension. A significant CaO-CaCO(3) chemical transformation (approximately 82% of carbonation efficiency) was estimated by pressure-mass balance after 2h of reaction at 30 degrees C. In addition, the qualitative comparison of X-ray diffraction spectra for reactants and products revealed a complete CaO-CaCO(3) conversion. The carbonation efficiency of CaO was independent on the initial pressure of CO(2) (10, 20, 30 and 40 bar) and it was not significantly affected by reaction temperature (room temperature "20-25", 30 and 60 degrees C) and by fly-ash dose (50, 100, 150 g). The kinetic data demonstrated that the initial rate of CO(2) transfer was enhanced by carbonation process for our experiments. The precipitate calcium carbonate was characterized by isolated micrometric particles and micrometric agglomerates of calcite (SEM observations). Finally, the geochemical modelling using PHREEQC software indicated that the final solutions (i.e. after reaction) are supersaturated with respect to calcium carbonate (0.7 < or = saturation index < or = 1.1). This experimental study demonstrates that 1 ton of fly-ash could sequester up to 26 kg of CO(2), i.e. 38.18 ton of fly-ash per ton of CO(2) sequestered. This confirms the possibility to use this alkaline residue for CO(2) mitigation. PMID:18539389

  14. 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)

  15. Nanominerals and nanoparticles in feed coal and bottom ash: implications for human health effects.

    Science.gov (United States)

    Silva, Luis F O; da Boit, Kátia M

    2011-03-01

    Environmental and human health risk assessments of nanoparticle effects from coal and bottom ash require thorough characterisation of nanoparticles and their aggregates. In this manuscript, we expand the study of human exposure to nanosized particles from coal combustion sources (typically pyrrhotite formation. The presence of iron oxide nanocrystals mixed with silicate glass particles emphasises the complexity of coal and bottom ash micromineralogy. Given the potentially bioreactive nature of such transition metal-bearing materials, there is likely to be an increased health risk associated with their inhalation. PMID:20422282

  16. 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 ?-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, ? 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 ? radiation dose rate inside building when the ash were rationally used as the raw materials of building

  17. Solid and fly ash materials ofbrown coal power plants, their characteristics and utilisation

    Directory of Open Access Journals (Sweden)

    Kovcs Ferenc

    2002-09-01

    Full Text Available coal-fired power plants, a significant amount of residues is produced, depending on the technical parameters of coal separation and firing equipment. A large quantity of solid and fly ash and, in the case of flue gas desulphurisation, REA gypsum and wash-water is produced. The quantity of residues depends primarily on the ash and sulphur content of the fuel.Coal has a significant role in energy production and represents a considerable quantity in electric energy generation. At the turn of the millenary, about 4 billion tones of black coal and 800 million tones of brown coal and lignite are produced in the world annually. Depending on the ash content of the coals ? it varies between 5-8% and 30-35% ?, the quantity of solid and fly ash produced by firing is 1.0-1.5 billion tones per year. The quantity of residues of this kind accumulated in the past amounts to 100 billion tones.As far as the residues of coal-fired power plants are concerned, the annual fuel demand of the power plants of the Rhenish brown coal basin, where the average ash content of lignite is 7% and the average sulphur content is 0.2-0.8%, is 1 Mt referred to a power plant capacity of 100 MW. 60-70 kt solid + fly ash and, in the case of flue gas desulphurisation, 12-15 kt of gypsum is produced annually, referred to a capacity of 100 MW. In the East German areas, after the reconstruction of power plants, 30-50 kt of fly ash and, because of the higher sulphur content, 25-30 kt of gypsum and 4-5000 m3 of wash-water is produced annually, referred to a capacity of 100 MW.The composition of Hungarian lignite is significantly different to that of Rhenish brown coal. The ash content and combustible sulphur content of domestic lignite is considerably higher. The ash content of lignite varies between 15 and 25%, the average is 20%. In Visonta, 160-200 tones of solid + fly ash is produced annually, referred to a power plant capacity of 100 MW. With the flue gas desulphuriser installed recently, one can expect a gypsum quantity of 40-60 kt/year, referred to a capacity of 100 MW.

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

    International Nuclear Information System (INIS)

    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)

  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. Comparison of heterogeneous photolytic reduction of Hg(II) in the coal fly ashes and synthetic aerosols

    Science.gov (United States)

    Tong, Yindong; Eichhorst, Terry; Olson, Michael R.; Rutter, Andrew P.; Shafer, Martin M.; Wang, Xuejun; Schauer, James J.

    2014-03-01

    In this study, we examined the heterogeneous reduction of Hg(II) on the coal fly ash samples and synthetic aerosols under different light conditions in a controlled laboratory reactor. Three types of coal fly ashes were studied: a high carbon fly ash from a stoker boiler, a low carbon/low sulfate fly ash from a pulverized coal combustor burning low sulfur coal, and a high sulfate fly ash from a pulverized coal combustor burning high sulfur coal. The rate of Hg(II) reduction on the three diverse fly ash samples was found to be relatively fast with an average half-life of 1.6 h under clear sky atmospheric conditions (under the irradiance of 1000 W/m2). The reduction rate in the low sulfate/low carbon fly ash was approximately 1.5 times faster than with the other coal fly ash samples. Synthetic aerosols made of carbon black and levoglucosan produced Hg(II) reduction rates similar to coal fly ashes. However, aerosols composed of adipic acid resulted in reduction rates that were 3-5 times faster. The sensitivity of adipic acid reduction to light source wavelength was found to be greater than for the coal fly ash and other synthetic aerosols. Aerosols made from the water extracts of coal fly ash samples produced reduction rates equal to or slightly higher than with the native fly ash suggesting that the soluble components of fly ash play a significant role in the reduction mechanism. The measured reduction rates are likely important in the chemical processing of mercury in power plant plumes and potentially in the atmosphere and should be considered for incorporation in atmospheric transport models that are used to understand the fate of atmospheric mercury.

  1. 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...

  2. The evaluation of geopolymer properties prepared by alkali activation of black coal ashes with high content of loss on ignition

    OpenAIRE

    Michalíková Františka; Krinická Ivana; Kolesárová Miroslava; Sisol Martin; Praščáková Mária

    2010-01-01

    The utilization of fly ashes in Slovakia is lower than in other countries and dumping of fly ashes prevails. The dumping changeschemical and phase composition of fly ashes and so it decreases possibilities for their utilization. Fly ashes are mainly used in buildingindustry, where the content of loss on ignition (LOI) is limited due to standards. Black coal fly ashes produced in Slovakia have a highcontent of loss on ignition – more than 20 % - so they straight utilization in building industr...

  3. 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.

  4. Coal ash usage in environmental restoration at the Hanford site

    Energy Technology Data Exchange (ETDEWEB)

    Scanlon, P.L.; Sonnichsen, J.C.; Phillips, S.J.

    1994-08-01

    The ash stockpiled next to the 284E steam plant is mixed fly ash, bottom ash, and slag. The ash consists of (1) baghouse residue and (2) a mixture of bottom ash and slag which is washed out of the bottom of the boilers daily. In 1991, a Toxicity Characteristic Leaching Procedure (TCLP) was performed on several samples of this ash (Hazen Research 1991). This procedure is designed to determine the mobility of organic and inorganic anatytes present in liquid, solid, or multiphasic wastes (EPA 1994). The ash tested came from surge bins, conveyor samples, and bottom ash and fly ash from the boilers at 284E. Antimony, cadmium, germanium, molybdenum, silver, thallium, tungsten, and vanadium were tested for, but on all samples were below detection Limits for the testing method. Analytes present in relatively high concentrations (but less than one part per thousand) included barium, boron, chromium, fluorine, and zinc. The size of ash particles passing through a Taylor sieve series was very evenly distributed from 1 to 200m.

  5. Methods for analysis of trace elements in coal, coal fly ash, soil, and plant samples. [59 refs

    Energy Technology Data Exchange (ETDEWEB)

    Slates, R.V.

    1976-11-01

    Results of a literature search are presented, and analytical methods are proposed for studies of trace elements in coal, coal ash residue, soil, and vegetation. Increased trace element levels in soils and plants collected near power plants have been reported by several investigators. Many sample dissolution and analysis techniques were used in the reported studies. A nine-laboratory comparison of trace element analyses for a variety of methods showed excessive variation relative to quoted uncertainty limits. Analysis results from a subsequent four-laboratory comparison of instrumental nuclear techniques for trace element analysis agreed with the National Bureau of Standards certified values for all nine elements determined. Instrumental neutron activation analysis, spark source mass spectrometry, and atomic absorption spectrometry are proposed as primary analysis methods for coal, coal ash, soil, and plants in a Savannah River Laboratory study of trace elements. Bomb procedures are proposed for dissolution of samples.

  6. 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.

  7. Mercury in coals and fly ashes from Republika and Bobov Dol Thermoelectric Power Plants

    International Nuclear Information System (INIS)

    Feed coal and fly ash samples were collected at Republika and Bobov Dol thermoelectric power plants (TPPs). The fly ashes (FAs) were collected from three rows of the hot-side electrostatic precipitators (ESPs) array. Each sample was wet-screened at 100, 200, 325 and 500 mesh. The coals and fly 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 different 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 fly ashes was also done in the present investigation. (authors)

  8. Chemical and mineralogical characterization of a South African bituminous coal and its ash, and effect on pH of ash transport water

    Energy Technology Data Exchange (ETDEWEB)

    Moitsheki, L.J.; Matjie, R.H.; Baran, A.; Mooketsi, O.I.; Schobert, H.H. [Sasol Technology Pty Ltd., Sasolburg (South Africa)

    2010-02-15

    Sasol utilizes a low-rank bituminous coal for steam and synthetic gas production. The ash produced is transported by water for further processing. Understanding the chemistry of coal and the resulting ash properties would allow a better understanding of the origin of high pH of water used during ash handling or transport. A main objective of this study was to identify the species responsible for high pH values of the ash transport water, when burning coal from the Sasolburg Mooikraal mine. The coal contained proportions of extraneous carbonates, i.e. CaMg(CO{sub 3}){sub 2}) and CaCO{sub 3}, that decompose at elevated temperatures to form CaO and MgO. The ash samples in this work contained free CaO, as verified by X-ray diffraction and ethylene glycol leaching. ICP-OES analysis of water leachates of the ash showed calcium dissolution into the water. The high pH values of the leachates were consistent with the expected pH of a saturated water solution of calcium hydroxide. Contact of the ash with water produced Ca(OH){sub 2}. For combustion of this coal, the high pH of the water used for ash transport can be attributed to the free CaO in the ash. The methodological approach to this study could be directly applicable to other coals and their ashes, even of different composition than the specific coal and ash used in this study.

  9. 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; Sander, Bo; Glarborg, Peter

    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...... 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...... ash) to the boiler, these alkali species were effectively removed both in the fly ash and in the deposits, and a more frequent shedding of the deposits was observed. The results imply that coal fly ash can be an effective additive to reduce ash deposition and corrosion problems in a pulverized wood...

  10. An application of hydrothermally crystallized coal ashes for waste water treatment, 2

    International Nuclear Information System (INIS)

    To provide an application of combustion coal ash, hydrothermal reaction of fly ash (FA) and clinker ash (CA) is performed and an investigation is carried out to determine the capability of the P type zeolite produced from these ashes to adsorb heavy metal ions. Hydrothermal reaction of FA and CA at 95 - 100 deg C is conducted with various concentrations of sodium hydroxide for various reaction times. Both types of ash are found to easily undergo crystallization to form P type zeolite (PZ) and hydroxy sodalite (HS) when treated with a sodium hydroxide solution (sodium hydroxide/coal ash = 10 v/w) for 18 hours. The FA-PZ and CA-PZ produced by the hydrothermal treatment have degrees of crystallinity in the range of 40 - 60 percent. It is seen that the degree of crystallinity gradually increases with increasing treatment time. The cristallinity of hydrothermally treated coal ash is also shown to have good correlation with the base substitution capacity and the maximum adsorption of ammonium ion. Furthermore, they are shown to effectively adsorb metal ions, in particular those of lead, cadmium and strontium. It is suggested that they may serve as an enrichment agent for low-level radioactive nuclides produced in nuclear power plants. They also seem to have the possibility of serving as a metal elution preventive for industrial wastes of some special types. (Nogami, K.)

  11. 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.

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

    International Nuclear Information System (INIS)

    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 CaCO3 versus Al2O3 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

  13. 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; Glarborg, Peter; Sander, Bo

    2013-01-01

    Ash transformation and deposition during pulverized wood combustion in a full-scale power plant boiler of 800 MWth were studied with and without the addition of coal fly ash. The transient ash deposition behavior was characterized by using an advanced deposit probe system at two boiler locations...... with flue gas temperatures of about 1300 C and 800 C, respectively. The mechanisms of ash transformation and deposit formation were elaborated through a detailed characterization of the collected deposits and fly ashes. The results implied that during pulverized wood combustion, the formation of...... became almost constant after a few hours. The formed deposits, especially those at the location with low flue gas temperatures, contained a considerable amount of K2SO4, KCl, and KOH/K2CO3. With the addition of a large amount (about 4 times of the mass flow of wood ash) of coal fly ash to the boiler...

  14. 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.

  15. Acidolysis of coal fly ash by Aspergillus niger

    Energy Technology Data Exchange (ETDEWEB)

    Torma, A.E.; Singh, A.K. (EG and G Idaho Inc., Idaho Falls, ID (United States). Center for Biological Processing Technology)

    1993-12-01

    The kinetics of aluminium extraction were investigated, using as-received and calcined fly ash samples and a pure culture of [ital Aspergillus niger]. This fungus metabolized sucrose to citric and oxalic acids, which were involved in the acidolysis of fly ash. Aluminium extraction from as-received fly ash was only 5-8%, whereas from calcined fly ash it was up to 93.5%. The order of reaction and the overall reaction rate constant were determined by the van't Hoff technique with respect to the concentration of calcined fly ash. A linearized form of a modified Monod expression was applied to the experimental data to assess the kinetic constants for the acidolysis process. Statistically designed experiments were carried out with calcined fly ash and synthetic solutions containing citric and oxalic acids to determine the optimum leaching conditions. The acidolysis reaction mechanism is discussed. 28 refs., 6 figs., 3 tabs.

  16. Technical note: Vetiver can grow on coal fly ash without DNA damage.

    Science.gov (United States)

    Chakraborty, Rajarshi; Mukherjee, Anita

    2011-02-01

    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 open lands or ash ponds located near power plants and this has lain to waste thousands of hectares all over the world. Wind and leaching are often the causes of off-site contamination from fly ash dumpsites. Vetiver (Vetiveria zizanioides) grown on fly ash for three months showed massive, mesh-like growth of roots which could have a phytostabilizing effect. The plant achieved this without any damage to its nuclear DNA as shown by comet assay done on the root nuclei, which implies the long-term survival of the plant on the remediation site. Also, when Vetiver is used for phytoremediation of coal fly ash, its shoots can be safely grazed by animals as very little of heavy metals in fly ash were found to be translocated to the shoots. These features make planting of Vetiver a practical and environmentally compatible method for restoration of fly ash dumpsites. Lack of DNA damage in Vetiver has been compared to that in a sensitive plant i.e. Allium cepa. Our results suggested that apart from traditional end-points viz. growth parameters like root length, shoot length and dry weight, comet assay could also be included in a battery of tests for initial, rapid and effective selection of plants for restoration and phytoremediation of polluted sites. PMID:21598787

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

    Science.gov (United States)

    Otter, Ryan R; Bailey, Frank C; Fortner, Allison M; Adams, S Marshall

    2012-11-01

    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, a 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 species differences in the bioaccumulation of arsenic and selenium and potential factors contributing to these differences (i.e., trophic dynamics and gut pH) 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 24.83mg/kg dry weight and ovary concentrations up to 10.40mg/kg dry weight at coal ash-associated sites. Investigations into the gut pH and trophic dynamics of redear sunfish and bluegill 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 differences ((15)N and (13)C) 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. PMID:22947506

  18. 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.

  19. Prospect of new energy. Effective utilization of coal ash (investigations into the problem of treatment of ash from the coal fired power generation); Shin energy tenbo. Sekitanbai no yuko riyo (sekitan karyoku hatsuden no hai shori mondai wo saguru)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    Described in this report are the methods for treating coal ash from coal fired power stations. The main elements of the coal ash, other than carbon, are SiO2, Al2O3, and CaO. When compared with the slag from the blaster furnace, the coal ash contains less CaO, which makes it subordinate as a subsidiary material. It is expected that Japan will have 10.2-million tons of coal ash in 2000 including 8-million ton to be produced by coal fired power generation. At the current time approximately 60% of the coal ash is being effectively utilized, 70% of it in the cement-related fields. In the cement-related fields, the coal ash is used not only as a substitute for clay but also as admixtures to fly ash cement and freshly mixed concrete. In other fields, it is used for dam construction in civil engineering, artificial light aggregate for house building, as material for walls, as fertilizer in the agriculture and fishery sector, for improving soil, for melting snow, as replacement for waste stone, and for filling up coal mines. The technologies under development for its utilization involve gas concrete light in weight and high in fluidity, lower layer material for roads, seawalls, aggregate for rut-free concrete, and aggregate for unbaked artificial gravel concrete, etc. 18 refs., 15 figs., 14 tabs.

  20. Extraction Characteristics of Selenium as Affected by Coal Fly Ash Type, Water Extractant, and Extraction Time

    OpenAIRE

    Mark A. Cantrell; Kristofor R. Brye; Miller, David M.; Esten Mason; Julian Fairey

    2014-01-01

    Selenium (Se) contamination can be a potential groundwater concern near un-lined coal ash landfills. Of all the Environmental Protection Agencys priority and non-priority pollutants, Se has the narrowest concentration range considered beneficial and detrimental for aquatic and terrestrial organisms. The effects of ash type (i.e., fresh and weathered), water-extractant type (i.e., deionized water, rainwater, and groundwater), and extraction time (i.e., 2 and 6 hours) on S...

  1. Natural radiation in fly ashes from coal thermal power stations in Spain

    International Nuclear Information System (INIS)

    Specific activity in samples of fly ashes from Spanish coal thermal power stations at Abono (Asturias), Andorra (Teruel), Alcudia (Mallorca) and Cercs (Barcelona) was analysed by gamma ray spectrometry. The values obtained permit us to quantify the presence of different natural radionuclides from /sup 232/Th, /sup 238/U, /sup 235/U series and /sup 40/K. The models are defined on the basis of these data to calculate the dosimetric impact caused by the use of fly ashes in the concrete

  2. Ash chemistry and mineralogy of an Indonesian coal during combustion: Part II - Pilot scale observations

    Energy Technology Data Exchange (ETDEWEB)

    Vuthaluru, H.B. [Department of Chemical Engineering, Curtin University of Technology, Kent Street, Bentley, Perth Western Australia 6102 (Australia); French, D. [CSIRO Energy Technology, Lucas Heights Science and Technology Centre, Private Mail Bag 7, Bangor New South Wales 2234 (Australia)

    2008-06-15

    This paper reports on combustion experiments carried out in a pilot scale furnace as a follow-up to research previously carried out using a drop-tube furnace to investigate the combustion behaviour of an Indonesian coal, in particular the effects of additives on ash chemistry, mineralogy and ash deposit formation. Combustion experiments were carried out in a pilot scale furnace to test the effectiveness of bauxite addition in reducing ash build-up. Samples collected from deposits on the slagging panels and fouling probe tubes, electrostatic precipitator fly ash, the furnace ash and tunnel ash were fully characterized using various analytical techniques. Experimental results substantiated earlier drop-tube observations suggesting that the use of raw coal with an addition of 3 wt.% bauxite would appear to offer the best performance with respect to slagging and fouling propensity in comparison to use of the raw coal alone. Observations on the reduction in glass content resulting from the addition of bauxite during PSF test runs support the earlier findings of the drop-tube tests. The reduction in glass content found in the slagging panel and fouling probe samples is comparable to that found in ash formation experiments conducted at 1400 C despite the observed differences in mineralogy. Although deposits are still likely to form as indicated by the PSF runs they appear to be more friable and hence amenable to removal by conventional methods such as frequent soot blowing. These findings demonstrate how the results of laboratory experiments can be combined with those of pilot scale trials to provide data for full-scale trials on the effects of additives in the remediation of ash problems associated with the firing low-rank coals. (author)

  3. Surface chemical characteristics of coal fly ash particles after interaction with seawater under natural deep sea conditions

    International Nuclear Information System (INIS)

    The surface chemical characteristics of coal fly ash (CFA) before and after interaction with Mediterranean deep seawater was studied by X-ray photoelectron spectroscopy (XPS). Significantly lower values of Si, Ca, and S and higher values of Mg and Cl were found in the retrieved CFA as compared to fresh CFA. It is suggested that hydrolysis of the oxide matrixes results in an alkaline environment which rapidly leads to several chemical reactions. The two most important are (a) dissolution of the amorphous silicate and the calcium phases and (b) precipitation of Mg(OH)2-brucite. A depth profile of the retrieved CFA was measured by both line-shape analysis of the XPS spectra and by consecutive cycle of sputtering. The thickness of the brucite layer is estimated to be 1.3 nm

  4. 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. These problems, however, are usually associated with excess or inappropriate CFA applications. The levels of PAHs and PCBs in CFA are generally low; their effects on soil biota, uptake by plants and soil persistence, however, need to be assessed. In spite of this, co-application of CFA with manure or SS to land enhances its effectiveness in soil improvements. PMID:25079682

  5. Manipulation of gasification coal feed in order to increase the ash fusion temperature of the coal to operate the gasifiers at higher temperatures / Johannes Chrisstoffel van Dyk

    OpenAIRE

    Van Dyk, Johannes Chrisstoffel

    2006-01-01

    Coal is a crucial feedstock for South Africa's unique synfuels and petrochemicals industry and used by Sasol as a feedstock to produce synthesis gas via the Sasol-Lurgi Fixed Bed Dry Bottom (FBDB) gasification process. The ash fusion temperature (AFT) gives detail information on the suitability of a coal source for gasification purposes, and specifically to the extent ash agglomeration or clinkering is likely to occur within the gasifier. Ash clinkering inside the gasifier can cause channel b...

  6. ACUTE PULMONARY AND SYSTEMIC EFFECTS OF INHALED COAL FLY ASH IN RATS: COMPARISON TO AMBIENT ENVIRONMENTAL PARTICLES

    Science.gov (United States)

    Although primary particle emissions of ash from coal-fired power plants are well controlled, coal fly ash (CFA) can still remain a significant fraction of the overall particle exposure for some plant workers and highly impacted communities. The effect of CFA on pulmonary and syst...

  7. Immobilization of chromate from coal fly ash leachate using an attenuating barrier containing zero-valent iron

    DEFF Research Database (Denmark)

    Astrup, Thomas; Stipp, S. L. S.; Christensen, Thomas Højlund

    2000-01-01

    The purpose of this investigation was (i) to test the effectiveness of a barrier engineered to remove Cr(VI) from leachates of higher pH and salinity typical of coal burning ashes and (ii) to determine which geochemical processes control Cr immobilization. Laboratory column and batch desorption...... traditional liners and leachate collection systems at coal ash storage and disposal sites....

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

    International Nuclear Information System (INIS)

    Highlights: ► The indirect CO2 mineralization by brown coal fly ash has been tested. ► A large CO2 capture capacity of fly ash under mild conditions was achieved. ► The kinetic analysis confirmed a fast reaction rate with low activation energy. ► The fly ash based capture process is highly efficient and cost-effective. - Abstract: The use of an industry waste, brown coal fly ash collected from the Latrobe Valley, Victoria, Australia, has been tested for the post-combustion CO2 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 CO2 capture capacity of fly ash under mild conditions has been confirmed. The CO2 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 CO2 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 CO2 capture capacity of this system has also proven to reach maximum 264 kg CO2/tonne 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.

  9. 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)

  10. Elemental composition of coal fly ash: Malta coal power station in the Mpumalanga province in South Africa case study using nuclear and related analytical techniques

    International Nuclear Information System (INIS)

    Epithermal neutron activation analysis along with ICP-OES, LA ICP-MS, and XRF were used to determine the elemental composition of coal fly ash from the Malta coal power station in the Mpumalanga province of South Africa. A total of 54 major, trace and rare-earth elements were obtained by the four analytical techniques. The results were compared and the discrepancies discussed to show the merits and drawbacks of each of the techniques. It was shown that the elemental content of this particular coal fly ash is of the same order as the NIST standard reference material Coal Fly Ash 1633b

  11. 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)

  12. [Leaching of Rare Earth Elements from Coal Ashes Using Acidophilic Chemolithotrophic Microbial Communities].

    Science.gov (United States)

    Muravyov, M I; Bulaev, A G; Melamud, V S; Kondrat'eva, T F

    2015-01-01

    A method for leaching rare earth elements from coal ash in the presence of elemental sulfur using communities of acidophilic chemolithotrophic microorganisms was proposed. The optimal parameters determined for rare element leaching in reactors were as follows: temperature, 45 degrees C; initial pH, 2.0; pulp density, 10%; and the coal ash to elemental sulfur ratio, 10 : 1. After ten days of leaching, 52.0, 52.6, and 59.5% of scandium, yttrium, and lanthanum, respectively, were recovered. PMID:26263628

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

    OpenAIRE

    Kyu H. Kim; Seog Y. Yoon; Hong C. Park

    2014-01-01

    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 13001500 C with the initial solid loadings of 3050 wt.%, interconnected macro-sized pore channels with nearly circular-shaped ...

  14. RECLAMATION OF ALKALINE ASH PILES AND PROTECTION OF THEIR ENVIRONMENT AGAINST DUSTING

    Science.gov (United States)

    The objective of this study was to develop methods to reclaim and stabilize by vegetation fly ash and bottom ash from bituminous and lignite fired power plants. The ash had been transported from the power plant as a slurry and disposed of in ponds. Ashes from these power plants w...

  15. Preparation of low-ash products from Slovak sub-bituminous coals - a material balance

    International Nuclear Information System (INIS)

    The fines of sub-bituminous coals from the Cigel and the Handlova Collieries in use as steam coal in coal-fired power plant were subjected to washing in a water-only cyclone (WOC) with the aim to obtain suitable input material for organic compounds extraction. The WOC with a diameter of 150 mm and a cone part consisting of three angle sections 135 grad - 75 grad - 20 grad was applied. Vortex finder (overflow) and spigot (underflow) diameters were of 68 mm and 14.6 mm, respectively. Two basic products overflow and underflow were obtained. The third one, slurry or circulating charge was also considered into total material balance of washing. Thus, the contents of ash, combustible matter, SiO2, Al2O3, CaO, MgO, FeTOTAL, STOTAL, SSULPHIDIC and As were determined in the products of washing. Subsequently, on the basis of analyses the recoveries of individual components into products of washing were calculated. The washing resulted in the obtaining of significantly de-ashed coal at the overflow of WOC. In such way a washed coal with ash content in dry basis of 6.99 % at a mass yield of 20.74 % was won in the case of coal from the Cigel Colliery. Similarly, in the case of coal from the Handlova Colliery and its eastern field the products with ash content in dry basis of 7.70 % and 9.01 % at mass yield of 29.37 % and 29.50 % were obtained. Finally, the washing resulted in over 90 % ash rejection and about 70 % total sulphur rejection. (authors)

  16. 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.

  17. 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.

  18. 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.

  19. Determination of ash content of coal using nuclear borehole logging spectrometric gamma-gamma technique

    International Nuclear Information System (INIS)

    During the past decade, increasing effort has been given to monitoring coal quality in the search, production and preparation sequence. Considerable research and development has been carried out on nuclear methods for determination of ash in coal. A number of nuclear techniques are now well established for coal analysis. In particular, the spectrometric gamma-gamma technique is based on the existence of a simple correlation between the ash content and the equivalent atomic number of coal. This technique records and uses the count rates of the backscatter spectrum. These count rates describe the changes in spectral shape which are due to ash content variations. This method is presented along with a short review of the physical background. The report includes the simulation of in situ borehole probe readings using a MONTE CARLO tracking program. Simulating the transport through matter of gamma-rays by MONTE CARLO techniques essentially attempts to reproduce the actual statistical nature of the interaction processes. Random numbers are used throughout, along with known nuclear data, to select the parameters which influence a particle's history. Such an approach can deal with complex geometries through which the particles move. Biaising or weightening techniques are applied for variance reduction, so as to minimise the statistical errors. The basic features of biaising as well as the description of the program are given. A semi-theoretical approach is discussed for the determination of ash content of coal seam using the simulated spectrum

  20. 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 quality information

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

    OpenAIRE

    Marlinda; Ramli; Muh. Irwan

    2015-01-01

    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...

  2. 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

  3. Some studies on the changes in the composition of coal ash and bottom/fly ash produced in atmospheric fluidized bed combustor

    International Nuclear Information System (INIS)

    A study on the ash of Lakhra lignite coal and the bottom/fly ash, obtained from combustion of Lakhra lignites in atmospheric fluidized bed combustor (AFBC) was carried out. It has been observed that the absence of alkali metals was of significant importance, as alkali metals were responsible for agglomeration in the AFBC. (author)

  4. Desulphurization Characteristic of Industry Alkaline Wastes during Coal Combustion

    OpenAIRE

    Bin Zheng; Chunmei Lu

    2009-01-01

    The desulphurization characteristics of four sorts of industry alkaline wastes and one sort of limestone were studied by means of flue gas analyzer and the high temperature tube reactor. Pore structure and desulphurization product char-acteristic were investigated respectively by mercury porosimeter and XRD diffraction technology. The reasons why wastes and limestone hold the different desulphurization capability were deeply discussed. The result shows that white clay and carbide slag could c...

  5. 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

  6. 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 during high-sulfur coal combustion. By contrast, the ??34S values for fly-ash samples from the low-sulfur Danville coal average 10.2???, only slightly enriched in 34S relative to those from the parent coal (average 7.5???). The ??34S values for bulk S determined directly from the fly-ash samples show close correspondence with the ??34S values for SO4- 2 leached from the fly ash in the low-sulfur coal, suggesting that the transition from pyrite to sulfate occurred via high-temperature oxidation during coal combustion. ?? 2007 Elsevier B.V. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

    Damla, Nevzat [Batman Univ. (Turkey). Dept. of Physics; Cevik, Ugur [Karadeniz Technical Univ., Trabzon (Turkey). Dept. of Physics; Kara, Ayhan [Osmaniye Korkut Ata Univ. (Turkey). Dept. of Physics

    2012-11-15

    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 {sup 226}Ra activity concentrations in coal, slag and fly ash were measured as 83, 99 and 38 Bq kg{sup -1}, respectively. The mean {sup 232}Th activity concentrations in coal, slag and fly ash were measured as 108, 113 and 50 Bq kg{sup -1}, respectively. The mean {sup 40}K activity concentrations in coal, slag and fly ash were found to be 366, 381 and 204 Bq kg{sup -1}, respectively. The potential radiological hazards associated to these materials were evaluated by calculating the radium equivalent activity (Ra{sub eq}), the air absorbed gamma dose rate (D), the annual effective dose rate (AED), the external hazard index (H{sub ex}) and internal hazard index (H{sub in}) and compared with the internationally accepted or reference values. The mean Ra{sub eq} values of the coal, fly ash and slag samples were lower than the recommended maximum values 370 Bq kg{sup -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{sup -1} and the corresponding outdoor annual effective doses are 0.60, 0.32 and 0.64 mSv y{sup -1}, which is higher than the worldwide average (0.07 mSv y{sup -1}), respectively. Moreover, the enrichment factors relative to the input coal are calculated for the radionuclide contents observed. Calculated enrichment factor values for {sup 226}Ra and {sup 232}Th were found 1.14 and 1.01, respectively. (orig.)

  8. Estabilizao de solo contaminado com zinco usando zelitas sintetizadas a partir de cinzas de carvo 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.

  9. Evaluation of interactions between soil and coal fly ash leachates using column percolation tests.

    Science.gov (United States)

    Tsiridis, V; Petala, M; Samaras, P; Sakellaropoulos, G P

    2015-09-01

    The aim of this work was the assessment of the environmental impact of different origin fly ashes with regard to their final disposal. The experimental procedure included the performance of single column tests and column tests of fly ash and soil in series. The appraisal of the potential environmental hazards was implemented using physicochemical analyses and bioassays. Two different fly ash samples were examined, one fly ash produced from the combustion of sub-bituminous coal (CFA) and one fly ash produced from the combustion of lignite (LFA). Single column percolation tests were performed according to NEN 7343 protocol, while fly ash/soil experiments were conducted incorporating slight modifications to this protocol. The study focused on the release of metals Ba, Cr, Cu, Mo, Se and Zn and the ecotoxic behavior of leachates on crustacean Daphnia magna and bacteria Vibrio fischeri. The infiltration of the leachates of both fly ashes through soil affected considerably their leaching profile. The transport of Cu and Zn was facilitated by the dynamic leaching conditions and influenced by the pH of the leachates. Moreover, the release and bioavailability of Cr, Cu and Zn was probably altered during the infiltration experiments and organisms' response was not always correlated with the concentration of metals. Nevertheless, the results are signalling that possible manipulations and final disposal of fly ash should be considered when environmental threats are investigated. PMID:26087643

  10. The accumulation of boron on Agropyron elongatum grown in coal fly ash and sewage sludge mixture

    International Nuclear Information System (INIS)

    A greenhouse pot experiment was conducted to investigate the boron (B) release capacity of coal fly ash and sewage sludge mixtures, and the accumulation of B in tall wheat grass (Agropyron elongatum) after two consecutive growing seasons. Sludge was amended with fly ash at application rates of 0, 5, 10, 35 and 50% (w/w), and each mixture was then mixed with a loamy soil at either 1:1 or 1:5 (v/v). Both water soluble B (WS-B) and hot water soluble B (HWS-B) increased with increasing fly ash amendment rate. Shoot B concentrations also increased significantly according to the rate of ash amendment. The ash-sludge mixture improved plant growth with the highest total dry weight yield at 10% ash amendment rate. Boron toxicity symptoms in leaf tips were observed at 35% and 50% ash amendment rate at both soil mixing ratios. Hot water soluble B and WS-B decreased significantly after consecutive cropping of (Agropyron) especially at low ratio of mixture with soil i.e., 1:5 (v/v). However, soil available B contents at > 35% ash application rate and 1:1 (v/v) soil mixing ratio were still excessive for normal plant growth, suggesting that deleterious effects on plant growth would be experienced in later seasons owing to the high amounts of residual B. 18 refs., 4 figs., 3 tabs

  11. 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.

  12. Trace element toxicity in VA mycorrhizal cucumber grown on weathered coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Dosskey, M.G.; Adriano, D.C. (University of Georgia, Aiken, SC (United States). Savannah River Ecology Lab.)

    1993-11-01

    Mycorrhizal colonization is widely recognized as enhancing plant growth on severely disturbed sites. A greenhouse pot experiment was conducted to determine if inoculation with vesicular-arbuscular mycorrhizal (VAM) fungi will enhance vegetation establishment on abandoned coal fly ash basinss, Spores of Glomus intraradices (Schenck and Smith) and Glomus etunicatum (Becker and Gerdemann) were added to weathered precipitator ash (EC-0.91 dSm[sup -1], pH 5.0) and to a pasteurized soils of the same pH (Grossarenic Paleudult, 92% sand, 1% organic matter). Some soil and ash were left unamended as non-mycorrhizal controls. Cucumber (Cucumis sativus L. cv. Poinsette 76) seeds were sown, watered regularly, and fertilized periodically with macronutrient solution. By 8 weeks all ash-grown plants exhibited smaller leaves with leaf margin curl and necrosis, and plant biomass was significantly less (0.75x) than soil-grown plants. Based on analysis of 18 elements in plant tissues, toxicity to B, Mn, or Zn could have caused growth suppression, confirming trace element problems for plant growth on fly ash. For plants grown on fly ash, G. etunicatum was the only fungus that colonized roots (20% of root length reduced from 67% on soil) and it suppressed plant growth to 0.80 x that of uninoculated ash-grown plants. Correspondingly, shoot Zn concentration in G. etunicatum-inoculated plants was 3.5 x higher than in uninoculated plants and at generally toxic levels (273 mg kg[sup -1]). Glomus etunicatum had no other significant effects on elemental concentrations. These results indicate that VAM colonization in acid, weathered fly ash suppressed plant growth by facilitating uptake of Zn to toxic levels, and implies a limitation to successful use of VAM for vegetation establishment on abandoned coal fly ash basins.

  13. Evaluation of ash content in coals of Chelyabinsk basin by well logging

    International Nuclear Information System (INIS)

    Based on a comparison of data from carbon assays on cores with data from logging measurements (resistivity logging, gamma-gamma logging-II, thermal logging), correlations of each geophysical parameter with the coal ash were obtained. To exclude the effect of borehole and other conditions of measurement, ratios of average values of the parameters in the interval of the coal stratum studied to the average value of the parameter for a reference coal stratum in the same borehole with known and established ash were used rather than absolute values. A dependence of the values of the 20 resistivity logging parameters on depth was noted. The most marked correlation, between the relative geophysical parameters and the ash, was establihsed for the zone 150 to 700 m deep. Graphs were prepared, and are presented, for determining the ash in this zone. The most reliable ash determination is guaranteed when a group of parameters and calculation of the average data for each of them are used. For calculating the precision, the results obtained for 55 intersecting strata were compared with data from penetration of a core in rock workings. Absolute average arithmetical divergences for the resistivity, thermal, gamma-gamma-II, and gamma-gamma-S logging methods were 3.0-5.3%, and for different groups of parameters, 2.0-3.4%

  14. 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.

  15. Leaching characteristics of coal and fly ash from Parichha Thermal Power Plant, Jhansi, U.P. (India)

    International Nuclear Information System (INIS)

    Nearly 73% of India's total installed power generation capacity is thermal based power plants, 90% of its coal-based thermal power plants. Coal-based thermal power plants produce approximately 100 million tones of fly ash annually. Indian coal is of poor quality with high ash contents (35-50%) and low calorific value (∼ 15 MJ/Kg). This results in higher coal consumption for each MW power. Power generation in India has increased 1362 MW in 1947 to about 1,38,251 MW in March 2009. India is worlds sixth largest energy consumer, accounting for 3.4% of global energy consumption. More than 80 Coal-based thermal power plants is producing 73,492.38 MW (53.15%) while 14,581.71 MW(10.54%) by Gas-based thermal power plants, 1,201.75 MW (0.069%) by Diesel-based thermal power plants, 10,175 MW (7.35%) by Wind power, 34,680.76 MW (25.08%) by Hydroelectric power and 4,120 MW (2.90%) by Nuclear power reactors. The use of coal in power generation has led to increasing environmental problems associated not only with gaseous emissions but also with the disposal of ash residues. In particular, the use of low quality coals with high ash content results in huge quantities of both fly ash and bottom ash to be disposed off. An important problem related to coal ash disposal is the heavy metal content of the residue. In this regard, experimental results of numerous studies indicate that toxic trace metals may leach when coal and fly ash come into contact with water. In this study, coal and fly ash samples obtained from Parichha Thermal Power plant, located about 25 km from Jhansi at Parichha in Jhansi of Uttar Pradesh, and were subjected to toxicity tests, namely, Toxicity Characteristic Leaching Procedure (TCLP) of the U.S. Environment Protection Agency (USEPA). (author)

  16. Cobalt(II removal from synthetic wastewater by adsorption on South African coal fly ash

    Directory of Open Access Journals (Sweden)

    Ochieng Aoyi

    2010-09-01

    Full Text Available Advanced wastewater-treatment techniques such as adsorption are essential in the removal of non- biodegradable toxic wastes from water. In this study, the use of South African coal fly ash, an industrial byproduct, has been investigated as a potential replacement for the current costly adsorbents used for removing heavy metals from wastewater. We utilised coal fly ash for the adsorption of cobalt(II ions from synthetic petrochemical wastewater and characterised its performance. A two-level three-factor full-factorial design was successfully employed for experimental design and analysis of the results. The combined effects of pH, initial concentration and adsorbent dose on cobalt(II removal were assessed using response surface methodology. Although the focus was on removal of cobalt(II, the adsorption was carried out in the presence of phenol and other heavy metal ions using the batch technique. The applicability of the Freundlich and Langmuir models to the equilibrium data was tested. Consequently, the equilibrium data was found to conform more favourably to the Freundlich isotherm than to the Langmuir isotherm; in this case, the coal fly ash had a maximum adsorption capacity of 0.401 mg/g for cobalt(II. We conclude that South African coal fly ash, as a natural, abundant and low-cost adsorbent, might be a suitable local alternative for elimination of cobalt(II from aqueous solutions.

  17. 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)

  18. 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.

  19. Laboratory study of air-water-coal combustion product (fly ash and FGD solid) mercury exchange

    Energy Technology Data Exchange (ETDEWEB)

    Mei Xin; Mae Sexauer Gustin; Kenneth Ladwig [University of Nevada, Reno, NV (United States). Department of Natural Resources and Environmental Science

    2006-11-15

    Recent laboratory research has indicated that coal fly ash derived from subbituminous and bituminous type coals is a sink for atmospheric mercury (Hg), however lignite-based ash was found to emit Hg to the air. Solids collected from systems with components that enhance Hg removal (i.e. activated carbon injection (ACI), flue gas desulfurization (FGD), and selective catalytic reduction (SCR) or selective non-catalytic reduction (SNCR)) may have higher Hg concentrations and therefore a higher potential for Hg release. For this study we investigated the potential for Hg release to the air and water from coal combustion products (CCPs) collected from coal-fired units with FGD equipment, SCR and SNCR equipment, and sorbent injection for Hg removal. In the laboratory study, most dry samples acted as sinks for atmospheric Hg in the dark at 25{sup o}C. When exposed to light or increased temperature (45{sup o}C), deposition of Hg to the fly ash substrates in most cases continued but decreased. Wet FGD samples emitted Hg. However, they became a sink for atmospheric Hg or exhibited low Hg emission rates when dried. Mercury flux in the dark at 25{sup o}C was correlated with fly ash carbon content (LOI). Most liquid extracts derived using the synthetic precipitation leaching procedure (SPLP EPA method 1312) had very low Hg concentrations ({lt}13 ng/l). 24 refs., 3 figs., 2 tabs.

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

    Science.gov (United States)

    Herndon, J Marvin

    2015-08-01

    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. PMID:26270671

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

    Science.gov (United States)

    Herndon, J. Marvin

    2015-01-01

    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. PMID:26270671

  2. 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 mod...

  3. Code making of automatic measurement for coal ash content using annihilation radiation

    International Nuclear Information System (INIS)

    In order to realize automatic measurement the Multichannel Computer Analyzer codes were made. This work directly supported the job of determination of ash content of coal using annihilation radiation. The code could not be copied by others and could kill virus by itself. It could be widely used in works of using Multichannel computer Analyzer

  4. Improved leaching test methods for environmental assessment of coal ash and recycled materials used on construction

    Science.gov (United States)

    Changes in air pollution control at coal-fired power plants will result in lower emissions of mercury and other pollutants. Fly ash, flue gas desulfurization gypsum, and other air pollution control residues are used in agricultural, commercial, and engineering applications. Resea...

  5. Preparation of low-ash products from Slovak sub-bituminous coals a material balance

    Directory of Open Access Journals (Sweden)

    tefan Jakabsk

    2010-11-01

    Full Text Available The fines of sub-bituminous coals from the Cge? and the Handlov Collieries in use as steam coal in coal-fired power plant weresubjected to washing in a water-only cyclone (WOC with the aim to obtain suitable input material for organic compounds extraction.The WOC with a diameter of 150 mm and a cone part consisting of three angle sections 135-75-20 was applied. Vortex finder (overflowand spigot (underflow diameters were of 68 mm and 14.6 mm, respectively. Two basic products overflow and underflow were obtained.The third one, slurry or circulating charge was also considered into total material balance of washing. Thus, the contents of ash,combustible matter, SiO2, Al2O3, CaO, MgO, FeTOTAL, STOTAL, SSULPHIDIC and As were determined in the products of washing. Subsequently,on the basis of analyses the recoveries of individual components into products of washing were calculated. The washing resultedin the obtaining of significantly deashed coal at the overflow of WOC. In such way a washed coal with ash content in dry basis of 6.99 %at a mass yield of 20.74 % was won in the case of coal from the Cge? Colliery. Similarly, in the case of coal from the Handlov Colliery andits eastern field the products with ash content in dry basis of 7.70 % and 9.01 % at mass yield of 29.37 % and 29.50 % were obtained.Finally, the washing resulted in over 90 % ash rejection and about 70 % total sulphur rejection.

  6. 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)

  7. 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.

  8. The use of tetragnathid spiders as bioindicators of metal exposure at a coal ash spill site.

    Science.gov (United States)

    Otter, Ryan R; Hayden, Mary; Mathews, Teresa; Fortner, Allison; Bailey, Frank C

    2013-09-01

    On 22 December 2008, a dike containing coal fly ash from the Tennessee Valley Authority Kingston Fossil Fuel Plant (TN, USA) failed, resulting in the largest coal ash spill in US history. The present study was designed to determine sediment metal concentrations at multiple site locations and to determine whether site-specific bioaccumulation of metals existed in tetragnathid spiders. Selenium and nickel were the only 2 metals to exceed the US Environmental Protection Agency sediment screening levels. Selenium concentrations in spiders were significantly higher at ash-affected sites than in those from reference sites. The ratio of methylmercury to total mercury in spiders was found to be similar to that in other organisms (65-75%), which highlights the potential use of tetragnathid spiders as an indicator species for tracing contaminant transfer between the aquatic and terrestrial ecosystems. PMID:23686551

  9. 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.

  10. 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...

  11. Experimental investigation of ash behavior and emissions during combustion of Bosnian coal and biomass

    International Nuclear Information System (INIS)

    This paper presents results of experimental research into the ash behavior of different Bosnian coal types and biomass fired in an electrically heated entrained pulverized fuel flow experimental reactor. The results are derived from a series of tests performed under a range of temperature and air conditions for the fuel test matrix. In essence, the experimental reactor comprises a 3 m length alumina-silicate ceramic tube, where combustion takes place, surrounded by SiC stick-type electric heaters and three-layer insulation. The temperature of the reaction zone is controlled by a programmable logic controller (PLC) with thyristor units for each of the heating zones, allowing the process temperature to be varied at will across the range from ambient to 1560 oC. The methodology is based on the evaluation of ash deposits formed in the experimental reactor during the tests. Test points, reflecting the different types of ash deposits, are plotted against appropriate fuel indicators onto graphic diagrams. Emissions of NO x and SO2 are also measured under different ambient conditions-at different temperatures and air distributions-to determine the emission figures for the fuels being tested. The results for six different fuels are presented, namely two single coals, two coal blends, and two coal-biomass blends. The results obtained support the thesis that the appropriate ambient conditions for combustion of coals and biomass can be recognized and recorded in this way

  12. 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

  13. Impact of fly ash from coal-fired power stations in Delhi, with particular reference to metal contamination

    Energy Technology Data Exchange (ETDEWEB)

    Mehra, A.; Farago, M.E.; Banerjee, D.K. [University of Derby, Derby (United Kingdom). School of Environmental and Applied Science

    1998-03-01

    Indraprastha Power Station (IPP station) and Rajghat Power House (RHP) are both coal-fired power stations in New Delhi. Ash content of the coal used ranges between 38-47%. The ash is collected in electrostatic precipitators which have an efficiency of 99.3% (IPP station), and 99.7% (RPH). There are instances of major dust pollution around the power stations from fly ash dispersal. The main method of disposal of fly ash from the power stations is by mixing with water; the resultant slurry is pumped through pipes to ash disposal ponds. The supernatant from these ponds is discharged into the River Yamuna. Field studies have revealed large quantities of fly ash being deposited into the river. Field studies, conducted in January 1995 investigated the impact of fly ash dispersal in the Delhi region with particular reference to metal contamination.

  14. Impact of fly ash from coal-fired power stations in Delhi, with particular reference to metal contamination

    International Nuclear Information System (INIS)

    Indraprastha Power Station (IPP station) and Rajghat Power House (RHP) are both coal-fired power stations in New Delhi. Ash content of the coal used ranges between 38-47%. The ash is collected in electrostatic precipitators which have an efficiency of 99.3% (IPP station), and 99.7% (RPH). There are instances of major dust pollution around the power stations from fly ash dispersal. The main method of disposal of fly ash from the power stations is by mixing with water; the resultant slurry is pumped through pipes to ash disposal ponds. The supernatant from these ponds is discharged into the River Yamuna. Field studies have revealed large quantities of fly ash being deposited into the river. Field studies, conducted in January 1995 investigated the impact of fly ash dispersal in the Delhi region with particular reference to metal contamination

  15. Changes in growth characters and nutrient acquisition of guava (psidium guajava l.) in response to coal ash

    International Nuclear Information System (INIS)

    Coal ash management would remain a great concern all over the world. Several studies proposed that there is an ample scope for safe utilization of coal ash as a soil ameliorant that may improve physical, chemical and biological properties of the soil and is a source of readily available plant micro and macro nutrient. With this concept a pot culture experiment was carried out in the eastern ghat high land zone of Odisha, India under open condition in the nursery. Different levels of coal ash and soil mixture were used in different combinations to check their effect on the physio-morphological and biochemical parameters of guava. The study on the effect of varying levels of coal ash on guava revealed that the combination of 50:50 and 25:75 coal ash and soil mixture increased the seed germination, seedling characteristics, biomass, vegetative growth and chlorophyll content of the seedlings. The increase in growth traits was attributed to increase in nutrient acquisition of plants grown under above combinations. On contrary 100% coal ash in the growing medium reduced seed germination, seedling vigour, growth and biomass per plant. The leaf nutrient status of N, P, K, Ca, Mg, S and the micro nutrients Zn, Mn, B, Mo, Fe and Cu were found to be higher in the treatments having higher proportion of coal ash in the growing medium than other treatments and the lowest was recorded in control ( no coal ash). The findings suggest that application of coal ash in certain proportion is beneficial in terms of growth parameters and nutrient acquisition in guava. (author)

  16. Feasibility of fly ash-based composite coagulant for coal washing wastewater treatment

    International Nuclear Information System (INIS)

    Highlights: ► Coal washing wastewater was analyzed. ► Several fly ash-based composite coagulants were prepared to treat coal washing wastewater. ► The effluent with the high COD and SS removal was obtained after treatment. - Abstract: In this study, several fly ash (FA)-based composite coagulants, leached by hydrochloric acid, were prepared to treat coal washing wastewater. The concentrations of Al3+ and Fe2+/Fe3+ in the leachates and coagulants were analyzed, and optimal experimental conditions, including coagulant dosage and initial pH, were determined using various analytical techniques (scanning electron microscopy, energy dispersive spectrometry, X-ray diffraction (XRD), X-ray fluorescence (XRF), particle-size analysis, zeta potential, pH and conductivity measurements). A suspended solids (SS) and chemical oxygen demand (COD) removal efficiency from the effluent treated by one of the coagulants reached 99.61% and 96.48%, respectively, at dosages of 10 g l−1 (initial pH of 9, adjusted by CaO). This indicates that the coagulant was an effective agent for coal washing wastewater treatment, and that the leached Al3+ and Fe3+ and introduced Ca2+ may have improved the coagulation process. Analysis of the dry sludge composition and slurry particle size distribution of the coal washing wastewater showed that charged colloidal particles and the fine particle distribution in the coal washing wastewater make the wastewater treatment a difficult process. Results from this study could provide a novel approach for the treatment of coal washing wastewater and coal fly ash utilization.

  17. 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.

  18. 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.

  19. Glass Ceramics Composites Fabricated from Coal Fly Ash and Waste Glass

    International Nuclear Information System (INIS)

    Great quantities of coal ash are produced in thermal power plants which present a double problem to the society: economical and environmental. This waste is a result of burning of coal at temperatures between 1100-14500C. Fly ash available as fine powder presents a source of important oxides SiO2, Al2O3, Fe2O3, MgO, Na2O, but also consist of small amount of ecologically hazardous oxides such as Cr2O3, NiO, MnO. The combination of the fly ash with waste glass under controlled sintering procedure gave bulk glass-ceramics composite material. The principle of this procedure is presented as a multi barrier concept. Many researches have been conducted the investigations for utilization of fly ash as starting material for various glass–ceramics production. Using waste glass ecologically hazardous components are fixed at the molecular level in the silicate phase and the fabricated new glass-ceramic composites possess significantly higher mechanical properties. The aim of this investigation was to fabricate dense glass ceramic composites using fly ash and waste glass with the potential for its utilization as building material

  20. Hazards from radioactivity of fly ash of Greek coal power plants (CPP)

    International Nuclear Information System (INIS)

    Fly ash and fine dispersion releases by coal combustion in Greek coal power plants are radioactive. Concentrations in the fly ash up to 20 pCi/g and 10 pCi/g were measured for 238U and 226Ra respectively (not in secular equilibrium). The radioactivity of fly ash deduces risks in two ways: a) from the escaping fly ash in particulate form or fine dispersion and b) from using fly ash as substitute for cement in concrete. In a room of dimensions 10 x 10x4 m3 the concentration of Radon in the air will be about 10-9 μCi/cm3. For the above estimation a concrete porosity of 5% and a wall thickness of 20 cm was used. The estimated concentration of Radon was about two orders of magnitude lower than that of the MPC of Radon in the air, which is about 10-9 μCi/cm3. It is pointed out that if a 25% porosity were used, the Radon concentration will be an order of magnitude higher. (U.K.)

  1. 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

  2. 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.

  3. Hydrothermal synthesis of belite cement from coal fly ashes with various CaO content

    International Nuclear Information System (INIS)

    This paper summarizes the results of hydrothermal synthesizing belite cement from reactive mixtures consisting of two waste kinds (bottom ash and fly ash) from fluidized brown coal combustion in Slovakian power plant and CaO (analytical grade reagent) addition with CaO/SiO2 molar ratio of 2 in rotating autoclave under various conditions (175 a 200 grad C; 2 and 4 hours; water and 0.2 and 0.5 % NaOH solution). Changes in structure and phase composition of hydrothermally synthesized belite precursors and subsequent calcinated products were compared with those of starting mixtures. Based on XRD diffraction patterns and infrared spectra of pre-treatment products, the formation of the new profiles corresponding to CSH and α-C2SH phases with low degree of ordering as belite precursors after hydrothermal treatment was confirmed. Optimal conditions of hydrothermal treatment of reactive mixtures were 200 grad C and 4 hours in water. Different phase composition of products before and after calcination depends upon waste quality and precursor's synthesis conditions. Optimal calcination temperature in term of product quality to belite in precursors prepared by hydrothermal treatment of reactive mixture based on fly ash is 800 grad C because gehlenite as cement hydration retarder isn't formed at this temperature. Evaluation of phase composition in hydrothermally treated products of reactive mixtures showed that bottom ash with high CaO content fixed in anhydrite form (44.1 %) as a very stable compound is not suitable as raw material for synthesizing belite phase whereas coal fly ash with low CaO content in anhydrite form (4.2 %) and its hydrothermal treatment in combination with subsequent heating offer opportunities for the utilization of coal fly ash as raw material for belite production. (authors)

  4. Effects of particle size and moisture content on the emanation of Rn from coal ash

    International Nuclear Information System (INIS)

    Measurements of the emanation coefficients of 222Rn from coal ash were performed. Samples of coal ash from a stoker-fired furnace were mechanically sized into four categories. The mean 226Ra concentration of these categories ranged from 11.82-16.77 dpm g-1 and increased as a function of decreasing particle size. The mean bulk density and mean specific gravity of these categories ranged from 0.488-0.944 g cm-3 and 2.017-2.390 g cm-3, respectively, and both increased as a function of decreasing particle size. Samples of coal ash from four pulverized coal-fired furnaces were obtained, and demonstrated mean 226Ra concentrations ranging from 6.44-7.59 dpm g-1. The mean bulk density and mean specific gravity of these samples ranged from 1.254-1.520 g cm-3 and 2.357-2.588 g cm-3, respectively. Construction of chambers and methods for measuring 222Rn emanation coefficients are described. The measured emanation coefficient is shown to be insensitive to ingrowth time at times greater than three days. Measurements of emanation coefficients from ash samples were conducted at moisture contents of 0, 1.0, 10, 20 and 40% moisture by weight, and showed an increase in the emanation coefficient as a function of moisture content up to about 20% moisture by weight. Above 20% moisture content, most samples showed a trend toward decreasing emanation coefficients. The fractionated ash samples showed an increase in the emanation coefficient as a function of decreasing particle size. An experiment was also conducted which confirmed that sample depth was insignificant in explaining the observed emanation coefficient over the range of depths used in the other experiments

  5. The effects of particle size and moisture content on the emanation of Rn from coal ash.

    Science.gov (United States)

    Barton, T P; Ziemer, P L

    1986-05-01

    Measurements of the emanation coefficients of 222Rn from coal ash were performed. Samples of coal ash from a stoker-fired furnace were mechanically sized into four categories. The mean 226Ra concentration of these categories ranged from 11.82-16.77 dpm g-1 and increased as a function of decreasing particle size. The mean bulk density and mean specific gravity of these categories ranged from 0.488-0.944 g cm-3 and 2.017-2.390 g cm-3, respectively, and both increased as a function of decreasing particle size. Samples of coal ash from four pulverized coal-fired furnaces were obtained, and demonstrated mean 226Ra concentrations ranging from 6.44-7.59 dpm g-1. The mean bulk density and mean specific gravity of these samples ranged from 1.254-1.520 g cm-3 and 2.357-2.588 g cm-3, respectively. Construction of chambers and methods for measuring 222Rn emanation coefficients are described. The measured emanation coefficient is shown to be insensitive to ingrowth time at times greater than three days. Measurements of emanation coefficients from ash samples were conducted at moisture contents of 0, 1.0, 10, 20 and 40% moisture by weight, and showed an increase in the emanation coefficient as a function of moisture content up to about 20% moisture by weight. Above 20% moisture content, most samples showed a trend toward decreasing emanation coefficients. The fractionated ash samples showed an increase in the emanation coefficient as a function of decreasing particle size. An experiment was also conducted which confirmed that sample depth was insignificant in explaining the observed emanation coefficient over the range of depths used in the other experiments. PMID:3700109

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

    Science.gov (United States)

    Izquierdo, Maria; Querol, Xavier; Davidovits, Joseph; Antenucci, Diano; Nugteren, Henk; Fernndez-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. PMID:19118943

  7. Coal fly ash-slag-based geopolymers: Microstructure and metal leaching

    Energy Technology Data Exchange (ETDEWEB)

    Izquierdo, Maria, E-mail: mariaizq@ija.csic.es [Institute of Earth Sciences ' Jaume Almera' -CSIC, Lluis Sole Sabaris s/n 08028 Barcelona (Spain); Querol, Xavier [Institute of Earth Sciences ' Jaume Almera' -CSIC, Lluis Sole Sabaris s/n 08028 Barcelona (Spain); Davidovits, Joseph [Cordi-Geopolymere, Espace Creatis, Z.A. Bois de la Chocque 02100 Saint-Quentin (France); Antenucci, Diano [Institut Scientifique de Service Public (ISSeP) 200, rue du Chera, B-4000 Liege (Belgium); Nugteren, Henk [Delft University of Technology, Faculty of Applied Sciences, DelftChemTech, Particle Technology Group, Julianalaan 136, 2628 BL Delft (Netherlands); Fernandez-Pereira, Constantino [University of Seville, School of Industrial Engineering, Department of Chemical and Environmental Engineering, Camino de los Descubrimientos s/n, 41092 Seville (Spain)

    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 immobilise 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.

  8. Coal fly ash-slag-based geopolymers: Microstructure and metal leaching

    International Nuclear Information System (INIS)

    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 immobilise 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.

  9. Geochemical characterization of arsenic-rich coal-combustion ashes buried under agricultural soils and the release of arsenic

    International Nuclear Information System (INIS)

    Highlights: ► Sources, mineralogy and mobility of As in coal-combustion ashes were investigated. ► After a dam failure in 1965, the spilled ashes were buried under agricultural soils. ► Primary carriers of As within coal-combustion ashes are aluminosilicate glasses. ► The most probable secondary carriers of labile As are oxyhydroxides of Si, Al, and Fe. ► Arsenic stored in ashes is a long-term contamination source for the environment. - Abstract: A combination of geochemical and mineralogical methods was used to determine the concentrations, mobility, and sources of As in coal-combustion ashes and soils in the vicinity of a thermal power plant at Nováky, central Slovakia. Fresh lagooned ash, ashes buried under agricultural soils for 45 a, and the overlying soils, contain high concentrations of As ranging from 61 to 1535 mg/kg. There is no differences in the water extractable percentages of As between the fresh lagooned ash and buried ashes, which range from 3.80% to 6.70% of the total As. This small amount of As may perhaps reside on the surfaces of the ash particles, as postulated in the earlier literature, but no evidence was found to support this claim. Electron microprobe analyses show that the dominant primary As carriers are the aluminosilicate glasses enriched in Ca and Fe. The acid NH4+-oxalate extraction hints that the oxyhydroxides of Si, Al, and Fe are the most probable secondary carriers of labile As. The X-ray absorption spectroscopy (XAS) analyses show that As in the lagooned and buried ashes occurs mostly as As(V). The long-term burial of the coal-combustion ash under agricultural soil did not cause any major change of its chemical composition or As lability compared to the fresh lagooned ash

  10. 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)

  11. Mercury capture by native fly ash carbons in coal-fired power plants

    OpenAIRE

    Hower, James C.; Senior, Constance L.; Suuberg, Eric M.; Robert H Hurt; Wilcox, Jennifer L.; Olson, Edwin S.

    2010-01-01

    The control of mercury in the air emissions from coal-fired power plants is an on-going challenge. The native unburned carbons in fly ash can capture varying amounts of Hg depending upon the temperature and composition of the flue gas at the air pollution control device, with Hg capture increasing with a decrease in temperature; the amount of carbon in the fly ash, with Hg capture increasing with an increase in carbon; and the form of the carbon and the consequent surface area of the carbon, ...

  12. Application of gamma ray transmission technique for rapid determination of ash content in coals

    International Nuclear Information System (INIS)

    Low energy photon scatter or gamma ray transmission technique using scintillation and proportional detectors has been developed and is being utilised for a rapid laboratory determination of ash content in coals. The experimentally measured attentuation co-efficients are correlated with the ash values determined by conventional method, and a stochastic relationship between the two is developed using the least square fit. The choice of source, detector and samole thickness is described and the effects of variations in density, moisture and iron content on the accuracy of results are discussed. (author)

  13. Mutagenicity of coal fly ash: a new bioassay for mutagenic potential in a particle feeding ciliate

    Energy Technology Data Exchange (ETDEWEB)

    Smith-Sonneborn, J. (Univ. of Wyoming, Laramie); Fisher, G.L.; Palizzi, R.A.; Herr, C.

    1981-01-01

    The use of the established mutagenesis assay in Paramecium as a prescreen for hazardous environmental particles is described. Since these protozoans ingest particles of the size respired by animals and man, the biological effects of the respirable fraction of fly ash particles were monitored in particle-feeding eukaryotic cells. Fly ash from coal combustion was utilized for these studies and was found to be mutagenic. The effects of physical and chemical treatment of the particle mutagenicity provided evidence for both heat-stable, heat-labile and acid extractable mutagenic agents.

  14. Study on ash deposition under oxyfuel combustion of coal/biomass blends

    OpenAIRE

    Fryda, L.; Sobrino, Celia; Cieplik, M.; Kamp, W.L. van de

    2010-01-01

    Combustion in an O₂/CO₂mixture (oxyfuel) has been recognized as a promising technology for CO₂capture as it produces a high CO₂concentration flue gas. Furthermore, biofuels in general contribute to CO₂reduction in comparison with fossil fuels as they are considered CO₂neutral. Ash formation and deposition (surface fouling) behavior of coal/biomass blends under O₂/CO₂combustion conditions is still not extensively studied. Aim of this work is the comparative study of ash formation and depositio...

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

    OpenAIRE

    Abdulhameed Umar Abubakar; Khairul Salleh Baharudin

    2012-01-01

    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 powe...

  16. Immobilization of heavy metals in polluted soils by the addition of zeolitic material synthesized from coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Querol, X.; Alastuey, A.; Moreno, N.; Alvarez-Ayuso, E.; Garcia-Sanchez, A.; Cama, J.; Ayora, C.; Simon, M. [CSIC, Barcelona (Spain)

    2006-01-01

    The use of zeolitic material synthesized from coal fly ash for the immobilization of pollutants in contaminated soils was investigated in experimental plots in the Guadiamar Valley (SW Spain). This area was affected by a pyrite slurry spill in April 1998. Although reclamation activities were completed in a few months, residual pyrite slurry mixed with soil accounted for relatively high leachable levels of trace elements such as Zn, Pb, As, Cu, Sb, Co, Tl and Cd. Phytoremediation strategies were adopted for the final recovery of the polluted soils. The immobilization of metals had previously been undertaken to avoid leaching processes and the consequent groundwater pollution. To this end, 1100 kg of high NaPl (Na{sub 6}(AlO{sub 2}){sub 6}(SiO{sub 2}){sub 10}{center_dot} 15H{sub 2}O) zeolitic material was synthesized using fly ash from the Teruel power plant (NE Spain), in a 10 m{sup 3} reactor. This zeolitic material was manually applied using different doses (10000-25000 kg per hectare), into the 25 cm topsoil. Another plot (control) was maintained without zeolite. Sampling was carried out 1 and 2 years after the zeolite addition. The results show that the zeolitic material considerably decreases the leaching of Cd, Co, Cu, Ni, and Zn. The sorption of metals in soil clay minerals (illite) proved to be the main cause contributing to the immobilization of these pollutants. This sorption could be a consequence of the rise in pH from 3.3 to 7.6 owing to the alkalinity of the zeolitic material added (caused by traces of free lime in the fly ash, or residual NaOH from synthesis).

  17. Coal ashes and FGD gypsum - by-product or waste?

    Energy Technology Data Exchange (ETDEWEB)

    Berg, W. vom; Feuerborn, H.J. [ECOBA - European Coal Combustion Products Association e.V., Essen (Germany)

    2007-07-01

    The production of coal combustion products (CCPs) has been increased by the years due to legal requirements for flue gas cleaning. The utilisation of CCPs is well established in some European countries, basd on long-term experience and technical as well as environmental benefits. In Europe (EU 27) about 100 million tonnes of CCPs are produced annually. The CCPs are mainly utilised in the building material industry, in civil engineering, in road construction, for construction work in underground coal mining as well as for recultivation and restoration purposes in open cast mines. (orig.)

  18. 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

  19. Experimental study of fly ash of Lakhra coal power plant in RCC beams

    International Nuclear Information System (INIS)

    Of the various industrial by-products, fly ash, a finely divided mineral residue generated from the combustion of pulverized coal in power plants, is the most abundant. Its utilization as mineral admixture in cement concrete transforms a costly liability into an economical proposition. Further more, the costs and environmental problems associated with its disposal are minimized or eliminated. This study comprises on RCC beams made with ordinary Portland cement and with different configurations of fly ash by replacing cement and fine aggregate. To achieve the aim of present study, total 27 RCC beams were made. Among 27 beams, 3 beams were made with normal concrete, 12 beams were made by replacing 25, 50, 75 and 100% of fine aggregate by fly ash and 12 beams were made by replacing 10, 25, 50, and 75% of cement by fly ash. The study of these beams was carried out in terms of Load deflection, ultimate strength, crack pattern and failure mode. By analyzing the test results, it was observed that the beams made by replacing 75% of fine aggregate by fly ash with 4 and 6 stirrups has shown less deflection and higher ultimate load carrying capacity whereas the beams made by replacing 50 and 75% of-cement by fly ash have given inferior behaviour in comparison to the beam made by ordinary portland cement concrete. (author)

  20. Radiotracer evaluation of coal-ash dust cyclone efficiency

    International Nuclear Information System (INIS)

    The efficiency of two types of cyclones (an old and a new one) for three ash granulometric classes (0-40, 40-80, 80-100 μm) was studied with the aid of 51Cr radiotracer. The total efficiency of cyclones was calculated by combination of granulometric distribution with mean class efficiency. The difference between the efficiencies of the two cyclone types is significant. The results showed that the efficiency of the new modified cyclone was about 15% higher than that of the old one. (author) 3 refs.; 3 figs

  1. Fluidised bed gasification of high-ash South African coals : an experimental and modelling study / André Daniël Engelbrecht

    OpenAIRE

    Engelbrecht, André Daniël

    2014-01-01

    South Africa has large coal reserves and produces approximately 74% of its primary energy from coal. Coal gasification using moving bed gasifiers is one of the most important coal utilisation technologies, consuming ± 17.5% of locally produced coal. This study was motivated by the need to investigate alternative coal gasification technologies for the utilisation of fine, high-ash and caking coals for future Integrated Gasification Combined Cycle (IGCC) and coal to liquids (CTL)...

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

    OpenAIRE

    Wu, Hao; 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 ...

  3. EVALUATION OF THE EFFECTS OF COAL FLY ASH AMENDMENTS ON THE TOXICITY OF A CONTAMINATED MARINE SEDIMENT

    OpenAIRE

    Burgess, Robert M.; Perron, Monique M.; Friedman, Carey L.; Suuberg, Eric M.; Pennell, Kelly G.; Cantwell, Mark G.; PELLETIER Marguerite C.; Ho, Kay T.; Serbst, Jonathan R.; Ryba, Stephan A.

    2009-01-01

    Approaches for cleaning-up contaminated sediments range from dredging to in situ treatment. In the present report, we discuss the effects of amending reference and contaminated sediments with coal fly ash to reduce the bioavailability and toxicity of a field sediment contaminated with polycyclic aromatic hydrocarbons (PAHs). Six fly ashes and a coconut charcoal were evaluated in 7 d whole sediment toxicity tests with a marine amphipod (Ampelisca abdita) and mysid (Americamysis bahia). Fly ash...

  4. Levels and patterns of polycyclic aromatic hydrocarbons in fly ash generated in Coal-fired power plant

    International Nuclear Information System (INIS)

    The burning of pulverized coal to produce energy for generation of electricity in thermal power plants results in huge quantity of coal ash of varying properties. Because of the increase in electricity production, the amount of ash produced will increase proportionally. A large percentage of coal fly ash is comprised of relatively inert materials, such as silica and other trace and toxic elements. The coal ash also contain organic constituents of potential environmental concern. So far, very few studies on characterization of organic constituents in fly ash have been reported in the literature. In the present study, the fly ashes generated from the power stations are investigated regarding the distribution of 14 PAHs. The total amount of PAHs in the fly ash samples varied between 45.8 ng/g and 257.7 ng/g. Lower molecular weight (MW) PAHs, were found to be predominant in the fly ash samples. The concentration of Benzo(a)pyrene, which is the most potent carcinogenic PAH was found to vary between 0.8 ng/g to 6.3 ng/g with a mean concentration of 2.5 ng/g. (author)

  5. Effects of fluxing agents on gasification reactivity and gas composition of high ash fusion temperature coal

    Directory of Open Access Journals (Sweden)

    Zhao Ruifang

    2015-01-01

    Full Text Available A Na-based fluxing agent Na2O (NBFA and a composite fluxing agent (mixture of CaO and Fe2O3 with mass ratio of 3:1, CFA for short were used to decrease the ash fusion temperature of the Dongshan and Xishan coal from Shanxi of China and make these coal meet the requirements of the specific gasification process. The main constituents of the fluxing agents used in this study can play a catalyst role in coal gasification. So it is necessary to understand the effect of fluxing agents on coal gasification reactivity and gas composition. The results showed that the ash fusion temperature of the two coal used decreased to the lowest point due to the eutectic phenomenon when 5 wt% of CFA or NBFA was added. Simultaneously, the gas molar ratio of H2/CO changed when CFA was added. A key application was thus found where the gas molar ratio of H2/CO can be adjusted by controlling the fluxing agent amount to meet the synthetic requirements for different chemical products.

  6. A laboratory instrument for determination of ash in brown coal and some results of its testing

    International Nuclear Information System (INIS)

    A computer controlled laboratory instrument for the determination of ash as well as calcium and iron oxides in brown coals has been developed. It consists of a measuring head, control unit and printing device. Its principle of operation is based on XRF and scattering of the low energy X-rays from a Pu-238 source. Algorithms of the operation, software and design of the instrument are described. Some results of its testing are provided. The instrument is designed for the application in laboratories of power plants and brown coal mines. 6 refs., 5 figs., 1 tab. (author)

  7. Utilization of coal fly ash in the glass-ceramic production.

    Science.gov (United States)

    Zhang, Jian; Dong, Wen; Li, Juan; Qiao, Liang; Zheng, Jingwu; Sheng, Jiawei

    2007-10-22

    Manufacturing the glass-ceramic has been proposed as a useful choice to recycle coal fly ash from power plants. In this work, a glass-ceramic of SiO2-Al2O3-Fe2O3-CaO family was synthesized by mixing 90 wt% of coal fly ash, from a power plant in west of China, with Na2O, and then melted at 1350 degrees C. The ceramization of the obtained glass was carried out at 770 degrees C for 2h. Esseneite and nepheline were found present as major crystal phases. The produced glass-ceramic exhibited good chemical durability as well as good mechanical properties. The toxicity characteristic leaching procedure (TCLP) method found that the glass-ceramic was non-hazardous. PMID:17764838

  8. 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)

  9. 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)

  10. 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.

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

    International Nuclear Information System (INIS)

    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

  12. 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. PMID:18063375

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

    Energy Technology Data Exchange (ETDEWEB)

    Mahur, A.K.; Kumar, R.; Mishra, M.; Sengupta, D.; Prasad, R. [Aligarh Muslim University, Aligarh (India)

    2008-03-15

    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 U-238, Th-232, and K-40 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.

  14. Analysis of brown coal fly-ash using X-ray photoelectron spectroscopy

    Science.gov (United States)

    Ersez, T.; Liesegang, J.

    1991-08-01

    The surface chemical composition of brown coal ash particles formed during combustion has been determined using the surface-sensitive technique of X-ray photoelectron spectroscopy (XPS). Samples taken from furnace heat exchanger tube surfaces were in both powder and aggregate form. Other samples were obtained directly using 1 cm 2 steel coupons on a sample holder designed for insertion into flue gases in an experimental furnace. This allowed comparison of the XPS analyses between the fly-ash samples so acquired. After initial XPS characterization, samples were subjected to rare-gas ion (Ar +) sputtering for depth profiling purposes. The XPS technique was thus used to detect any sputter-induced composition changes or to observe any difference between the surface and bulk compositions of the ash. It was also observed that certain steels used for heat exchanger piping may well be pre-disposed to aluminosilicate fouling due to their intrinsic Al content.

  15. Arsenic and copper stabilisation in a contaminated soil by coal fly ash and green waste compost.

    Science.gov (United States)

    Tsang, Daniel C W; Yip, Alex C K; Olds, William E; Weber, Paul A

    2014-09-01

    In situ metal stabilisation by amendments has been demonstrated as an appealing low-cost remediation strategy for contaminated soil. This study investigated the short-term leaching behaviour and long-term stability of As and Cu in soil amended with coal fly ash and/or green waste compost. Locally abundant inorganic (limestone and bentonite) and carbonaceous (lignite) resources were also studied for comparison. Column leaching experiments revealed that coal fly ash outperformed limestone and bentonite amendments for As stabilisation. It also maintained the As stability under continuous leaching of acidic solution, which was potentially attributed to high-affinity adsorption, co-precipitation, and pozzolanic reaction of coal fly ash. However, Cu leaching in the column experiments could not be mitigated by any of these inorganic amendments, suggesting the need for co-addition of carbonaceous materials that provides strong chelation with oxygen-containing functional groups for Cu stabilisation. Green waste compost suppressed the Cu leaching more effectively than lignite due to the difference in chemical composition and dissolved organic matter. After 9-month soil incubation, coal fly ash was able to minimise the concentrations of As and Cu in the soil solution without the addition of carbonaceous materials. Nevertheless, leachability tests suggested that the provision of green waste compost and lignite augmented the simultaneous reduction of As and Cu leachability in a fairly aggressive leaching environment. These results highlight the importance of assessing stability and remobilisation of sequestered metals under varying environmental conditions for ensuring a plausible and enduring soil stabilisation. PMID:24859701

  16. The analysis of coal-and coke ashes by atomic absorption spectrophotometry

    International Nuclear Information System (INIS)

    In order to provide better conditions for the control of the chemical composition of the load in the USIMINAS blast furnaces, a method of analysis for sodium, potassium, iron, aluminium, calcium, magnesium and maganese in coal-and coke ash by atomic absorption spectrophotometry was developed. The precision of the calibration curves and the reproducibility of the results are given, together with an estimate of the speed compared with conventional methods of chemical analysis

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

    OpenAIRE

    J. Marvin Herndon

    2015-01-01

    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...

  18. Photosynthetic pigment concentrations, gas exchange and vegetative growth for selected monocots and dicots treated with two contrasting coal fly ashes

    Energy Technology Data Exchange (ETDEWEB)

    Yunusa, I.A.M.; Burchett, M.D.; Manoharan, V.; DeSilva, D.L.; Eamus, D.; Skilbeck, C.G. [University of Technology Sydney, Sydney, NSW (Australia). Dept. of Environmental Science

    2009-07-15

    There is uncertainty as to the rates of coal fly ash needed for optimum physiological processes and growth. In the current study we tested the hyothesis that photosynthetic pigments concentrations and CO{sub 2} assimilation (A) are more sensitive than dry weights in plants grown on media amended with coal fly ash. We applied the Terrestrial Plant Growth Test (Guideline 208) protocols of the Organization for Economic Cooperation and Development (OECD) to monocots (barley (Hordeum vulgare) and ryegrass (Secale cereale)) and dicots (canola (Brasica napus), radish (Raphanus sativus), field peas (Pisum sativum), and lucerne (Medicago sativa)) on media amended with fly ashes derived from semi-bituminous (gray ash) or lignite (red ash) coals at rates of 0, 2.5, 5.0, 10, or 20 Mg ha(-1). The red ash had higher elemental concentrations and salinity than the gray ash. Fly ash addition had no significant effect on germination by any of the six species. At moderate rates ({<=}10 Mg ha{sup -1}) both ashes increased (P < 0.05) growth rates and concentrations of chlorophylls a and b, but reduced carotenoid concentrations. Addition of either ash increased A in radish and transpiration in barley. Growth rates and final dry weights were reduced for all of the six test species when addition rates exceeded 10 Mg ha{sup -1} for gray ash and 5 Mg ha{sup -1} for red ash. We concluded that plant dry weights, rather than pigment concentrations and/or instantaneous rates of photosynthesis, are more consistent for assessing subsequent growth in plants supplied with fly ash.

  19. 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 60C 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

  20. 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

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

    International Nuclear Information System (INIS)

    The 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)

  2. Agricultural application of coal ash and its radioactive contamination to environment

    International Nuclear Information System (INIS)

    Sampling from the electric power plants of Beijing, Inner Mongolia, Ningxia, Hebei, Guangdong and Tianjin, coal ash samples were determined respectively by HPGe γ spectrometer analyzer. The results show that the main composition of radioactive substances are 23'8U, 232Th, their daughter nuclides and 40K. The range of specific radioactivity for 238U is 93.2-283.8 Bq/kg, for 232Th, 80.3-238.8 Bq/kg and for 40K, 115.6-447.4 Bq/kg. When amount of the coal ash applied is up to 675 t/hm2 the specific radioactivity of 226Ra and 228Ra are 3.56 and 2.60 times higher than those of control respectively. The increase of natural specific activity in soil varies with the amount of the coal ash applied, the expression of coefficient curve for 228Ra is y = 22.04 x +17.25 (r2 0.9909) and for 226Ra, y = 21.38 x + 2.45 (r2 = 0.9966). The same trend is shown with absorbed dose in air (D) and the annual effective dose (H), for D, y = 1.896 x + 3.875 (r2 = 0.9891) and for H, y = 23.245 x + 47.505 (r2 0.9891)

  3. Metal accumulation and health effects in raccoons (Procyon lotor) associated with coal fly ash exposure.

    Science.gov (United States)

    Souza, Marcy J; Ramsay, Edward C; Donnell, Robert L

    2013-05-01

    Approximately 5.4 million cubic yards of coal fly ash and water spilled into the Emory River embayment of Watts Bar Reservoir in east Tennessee on Dec 22, 2008. Raccoons were collected in 2009 and 2010 from the spill site (10/y) and unexposed areas (5/y) to determine whether metals and metalloids were accumulating in raccoons and if any negative health effects resulted from exposure to the spilled coal fly ash. Tissues were analyzed from each animal to determine the concentrations of 26 metals/metalloids. Complete blood cell counts (CBC), plasma biochemistry panels, and histopathology of select tissues also were performed. Results were analyzed by year and exposure status. Although significant differences were present in some tissues for some metals/metalloids, only arsenic in hair, iron in muscle, nickel in hair, selenium in hair and muscle, strontium in hair, and vanadium in hair and liver were increased in spill site animals (one or both years) compared with unexposed animals. No clinically important differences were observed between groups regarding CBC or plasma biochemistry analyses. Lesions were observed on histopathology in some tissues, but there was no difference in the prevalence of lesions between spill site and unexposed animals. There does not seem to be any important accumulation of metals/metalloids or negative health effects in raccoons associated with exposure to coal fly ash compared with unexposed animals. PMID:23292273

  4. 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 (C?m 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

  5. 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

  6. Chemical fractionation tests on South African coal sources to obtain species-specific information on ash fusion temperatures (AFT)

    Energy Technology Data Exchange (ETDEWEB)

    J.C. van Dyk; L.L. Baxter; J.H.P. van Heerden; R.L.J. Coetzer [Sasol Technology, Sasolburg (South Africa). Syngas and Coal Technologies, R& amp; D Division

    2005-10-01

    Detailed coal and feedstock characteristics are essential to predict gasification performance when a specific coal source is to be gasified. One property that specifically gives detail information on the suitability of a coal source for gasification purposes is the ash fusion temperature (AFT). The AFT of a coal source indicates the extent to which ash agglomeration and ash clinkering are likely to occur within the gasifier. The principal aim of this paper is to obtain mineral species-specific information on ash properties and the specific affect on AFT. Chemical fractionation treatment resulted in coals having different mineral properties that can be used to explain the affect of specific minerals on the AFT of coal. The highest concentration and species of minerals were removed from the coal by acid leaching (HCl and HNO{sub 3}) where Al, Ca, Mg, Na and Fe were removed in high concentrations from the coal. The AFT of coal after leaching increased to {gt}1600{sup o}C. Based on the 95% confidence intervals depicted the following components can be highlighted as having a statistical significant effect on the AFT: Al{sub 2}O{sub 3}, Fe{sub 2}O{sub 3}, CaO, MgO, P{sub 2}O{sub 5} and SiO{sub 2}-Al{sub 2}O{sub 3} combination. When mineral ratio was used, the best correlation coefficient ) with AFT was obtained with the dolomite ratio. This is in agreement with the results obtained from the correlations between the AFT and the ash composition where CaO and MgO resulted in the best correlation with AFT. Results presented in this paper again highlights the fact and confirmed work from other researchers that ash composition (elemental analyses) on its own does not explain AFT behavior or commercial performance of coal accurately. 14 refs., 6 figs., 6 tabs.

  7. Bibliographic review on organic compounds in coal ash; Etude bibliographique sur les composes organiques dans les cendres de charbon

    Energy Technology Data Exchange (ETDEWEB)

    Soreau, S.

    1996-12-31

    Production of ash by conventional fossil-fuel power plants is more closely watched by plant operators, due to the increase environmental regulatory constraints. A number of studies have been conducted in recent years to improve understanding of the physical and chemical characteristics of ash in relation to the fuels, equipment and operating conditions of the plants. The purpose of this study was to establish a bibliographical summary of the various families of organic compounds found in coal ash, and on their concentrations, their conditions of formation and adsorption on ash and their possible impact on the environment. In particular, we examined pollutants targeted by current regulations or regulations now being drawn up with respect to combustion installations. The study revealed the presence of a high number of organic compounds in coal ash. Many aliphatics, monocyclic aromatics and carbonyls are found, as well as heavier compounds which have become a matter of concern to scientists and public authorities in recent years because of their toxicity: polycyclic aromatic hydrocarbons (PAHs) and dioxins and furans (PCDDs and PCDFs). Their generally low concentrations can vary from a few pg/g to several dozen {mu}g/g. Among these compounds, dioxins and furans are found in the lowest concentrations, close to the thresholds of detection (pg/g). PAHs, most of which are non-carcinogenic, are normally found in concentrations from a few ng/g to a few hundred ng/g in the case of fly ash. These concentrations are often lower than those found in the ground and in fly ash from municipal incinerators. Furthermore coal bottom ash contains PAH concentrations which can exceed those found in coal fly ash by 2 orders of magnitude. It is difficult to analyze the environmental impact of such compounds, due to the lack of data on leaching. Most often, the authors agree that the risk that the organic compounds in coal ash will endanger the environmental are limited. (author) 58 refs.

  8. Quantitative determination of phases in the alkaline activation of fly ash. Part II: Degree of reaction

    Energy Technology Data Exchange (ETDEWEB)

    A. Fernandez-Jimenez; A.G. de la Torre; A. Palomo; G. Lopez-Olmo; M.M. Alonso; M.A.G. Aranda [Eduardo Torroja Institute (CSIC), Madrid (Spain)

    2006-10-15

    A working procedure was developed for determining the degree of reaction of fly ash subjected to alkali activation (with 8 M NaOH) at mild temperatures. Since the reaction products dissolve in HCl, the residue left after this acid attack contains only the fraction of the original ash that failed to react with the basic solution. This residue was analysed with Rietveld XRPD quantification and NMR and the findings were compared to the results of the analyses run on the activated ash to obtain a very precise quantification of all of the (crystalline, vitreous and amorphous) phases present in the systems studied. 25 refs., 4 figs., 7 tabs.

  9. Brick manufacture with fly ash from Illinois coals. Quarterly technical report, September 1, 1994--November 30, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, R.E.; Dreher, G.; Frost, J.; Moore, D.; Rostam-Abadi, M.; Fiocchi, T.; Swartz, D.

    1995-03-01

    This investigation seeks to utilize fly ash in fired-clay products such as building and patio bricks, ceramic blocks, field and sewer tile, and flower pots. This goal is accomplished by (1) one or more plant-scale, 5000-brick tests with fly ash mixed with brick clays at the 20% or higher level; (2) a laboratory-scale study to measure the firing reactions of a range of compositions of clay and fly ash mixtures; (3) a technical and economic study to evaluate the potential environmental and economic benefits of brick manufacture with fly ash. Bricks and feed materials will be tested for compliance with market specifications and for leachability of pollutants derived from fly ash. The laboratory study will combine ISGS databases, ICCI-supported characterization methods, and published information to improve predictions of the firing characteristics of Illinois fly ash and brick clay mixtures. Because identical methods are used to test clay firing and coal ash fusion, and because melting mechanisms are the same, improved coal ash fusion predictions are an expected result of this research. If successful, this project should convert an environmental problem (fly ash) into valuable products - bricks. During this quarter, the authors set up the manufacturing run at Colonial Brick Co., provided an expanded NEPA questionnaire for DOE, made preliminary arrangements for a larger brick manufacturing run at Marseilles Brick Co., revised laboratory procedures for selective dissolution analysis, and began characterization of brick clays that could be mixed with fly ash for fired-clay products.

  10. Removal of toxic and alkali/alkaline earth metals during co-thermal treatment of two types of MSWI fly ashes in China.

    Science.gov (United States)

    Yu, Jie; Qiao, Yu; Jin, Limei; Ma, Chuan; Paterson, Nigel; Sun, Lushi

    2015-12-01

    This study aims to vaporize heavy metals and alkali/alkaline earth metals from two different types of fly ashes by thermal treatment method. Fly ash from a fluidized bed incinerator (HK fly ash) was mixed with one from a grate incinerator (HS fly ash) in various proportions and thermally treated under different temperatures. The melting of HS fly ash was avoided when treated with HK fly ash. Alkali/alkaline earth metals in HS fly ash served as Cl-donors to promote the vaporization of heavy metals during thermal treatment. With temperature increasing from 800 to 900C, significant amounts of Cl, Na and K were vaporized. Up to 1000C in air, less than 3% of Cl and Na and less than 5% of K were retained in ash. Under all conditions, Cd can be vaporized effectively. The vaporization of Pb was mildly improved when treated with HS fly ash, while the effect became less pronounced above 900C. Alkali/alkaline earth metals can promote Cu vaporization by forming copper chlorides. Comparatively, Zn vaporization was low and only slightly improved by HS fly ash. The low vaporization of Zn could be caused by the formation of Zn2SiO4, ZnFe2O4 and ZnAl2O4. Under all conditions, less than 20% of Cr was vaporized. In a reductive atmosphere, the vaporization of Cd and Pb were as high as that in oxidative atmosphere. However, the vaporization of Zn was accelerated and that of Cu was hindered because the formation of Zn2SiO4, ZnFe2O4 and ZnAl2O4 and copper chloride was depressed in reductive atmosphere. PMID:26303652

  11. Radon exhalation rate from coal ashes and building materials in Italy

    International Nuclear Information System (INIS)

    The Italian National Electricity Board, in cooperation with Centro Informazioni Stubi Esperienze (CISE) has a program to assess the hazards connected with using fly ash in civil applications as partial substitutes for cement and other building materials. We investigated the natural radioactivity levels of more than 200 building materials. The survey involved materials available in Italy, categorized by geographical location and type of production. We also examined approximately 100 samples of fly ash from United States and South African coal, obtained from Italian power plants. Exhalation rates from about 40 powdered materials were determined by continuously measuring radon concentration growth in closed containers. Measurements were also performed on whole bricks, slabs, and titles. Details about the high-sensitivity measuring devices are presented. The influence of fly ash on exhalation rates was investigated by accurately measuring radon emanation from slabs with various ash/cement ratios and with slabs of inert materials having various radium concentrations. We will discuss results of forecasting indoor radon concentrations under different ventilation conditions. Two identical test rooms are being built, one with conventional and one with fly-ash building materials, to compare theoretical calculations with experimental data. Specifications for instruments to control and to measure the most important parameters are also discussed

  12. Coal Fly Ash as a Source of Iron in Atmospheric Dust

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Haihan; Laskin, Alexander; Baltrusaitis, Jonas; Gorski, Christopher A.; Scherer, Michelle; Grassian, Vicki H.

    2012-01-18

    Anthropogenic coal fly ash aerosols may represent a significant source of bioavailable iron in the open ocean. Few measurements have been made to compare the solubility of atmospheric iron from anthropogenic aerosols and other sources. We report an investigation of the iron dissolution of three fly ash samples in acidic aqueous solutions and compare the solubilities with that of Arizona test dust, a reference material of mineral dust. The effects of pH, cloud processing, and solar irradiation on Fe solubility were explored. Similar to previously reported results on mineral dust, iron in aluminosilicate phases provide predominant dissolved iron compared with iron in oxides. Iron solubility of fly ash is higher than Arizona test dust, especially at the higher pH conditions investigated. Simulated atmospheric processing elevates iron solubility due to significant changes in the morphology aluminosilicate glass, a dominantly material in fly ash particle. Iron continuously releases into the aqueous solution as fly ash particles break up into smaller fragments. The assessment of dissolved atmospheric iron deposition fluxes, and their effect on the biogeochemistry at ocean surface should be constrained by taking into account the source, environment pH, Fe speciation, and solar radiation.

  13. 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 10min 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

  14. Engineering analysis and comparison of new processes for the recovery of resource materials from coal ash

    Energy Technology Data Exchange (ETDEWEB)

    Canon, R.M.; Seeley, F.G.; Watson, J.S.

    1979-01-01

    During the past 2 years, several promising new processes for the recovery of valuable resource materials from coal ash, primarily power plant fly ash, have been conceived and investigated at the Oak Ridge National Laboratory. These processes, which include direct acid leach, the salt-soda sinter process, and the Calsinter (CaSo/sub 4/-CaCO/sub 3/) process, are designed to remove the major metals (aluminum, iron, and titanium) from fly ash; however, some are also capable of recovering trace metals. The sintering processes are particularly efficient in metal recovery and perhaps can produce nonhazardous solid wastes, as defined by the Resource Conservation and Recovery Act. The salt-soda sinter process can recover 95% of the aluminum and 90% of the iron and titanium while producing a solid containing mostly silicates similar to silica gel. The Calsinter process recovers approximately the same amounts of the metals and produces solids similar to plaster of Paris. This process is particularly attractive because it can consume large amounts of flue-gas desulfurization (FGD) sludge as well as fly ash. Engineering and preliminary cost analyses have been prepared for these processes (and the lime-soda sinter process) for a plant consuming one million tons of fly ash (dry basis) per year. A comparison of strengths and weaknesses of the various processes is presented.

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

    Energy Technology Data Exchange (ETDEWEB)

    Yongqi Lu; Massoud Rostam-Abadi; Ramsay Chang; Carl Richardson; Jennifer Paradis [Illinois State Geological Survey, Champaign, IL (United States)

    2007-08-15

    Nine fly ash samples were collected from the particulate collection devices of four full-scale pulverized coal utility boilers burning eastern bituminous coals and three cyclone utility boilers burning either Powder River Basin coals or PRB blends. As-received fly ash samples were mechanically sieved to obtain six size fractions. Unburned carbon content, mercury content, and Brunauer-Emmett-Teller 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 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. 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-PC ashes, appeared to be important for the mercury adsorption. 26 refs., 16 figs., 2 tabs.

  16. Catastrophic dispersion of coal fly ash into oceans during the latest Permian extinction

    Energy Technology Data Exchange (ETDEWEB)

    Grasby, S.E.; Sanei, H.; Beauchamp, B. [Geological Survey Canada Calgary, Calgary, AB (Canada)

    2011-02-15

    During the latest Permian extinction about 250 Myr ago, more than 90% of marine species went extinct, and biogeochemical cycles were disrupted globally. The cause of the disruption is unclear, but a link between the eruption of the Siberian Trap flood basalts and the extinction has been suggested on the basis of the rough coincidence of the two events. The flood basalt volcanism released CO{sub 2}. In addition, related thermal metamorphism of Siberian coal measures and organic-rich shales led to the emission of methane, which would have affected global climate and carbon cycling, according to model simulations. This scenario is supported by evidence for volcanic eruptions and gas release in the Siberian Tunguska Basin, but direct indicators of coal combustion have not been detected. Here we present analyses of terrestrial carbon in marine sediments that suggest a substantial amount of char was deposited in Permian aged rocks from the Canadian High Arctic immediately before the mass extinction. Based on the geochemistry and petrology of the char, we propose that the char was derived from the combustion of Siberian coal and organic-rich sediments by flood basalts, which was then dispersed globally. The char is remarkably similar to modern coal fly ash, which can create toxic aquatic conditions when released as slurries. We therefore speculate that the global distribution of ash could have created toxic marine conditions.

  17. Mineralogy and microstructure of ash deposits from the Zhuzhou coal-fired power plant in China

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Junying; Wei, Chao; Zheng, Chuguang [State key laboratory of coal combustion, Huazhong University of Science and Technology, Wuhan 430074 (China); Zhao, Yongchun [State key laboratory of coal combustion, Huazhong University of Science and Technology, Wuhan 430074 (China); School of Mechanical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Yao, Bin [School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2010-04-01

    Ash deposition is one of the major problems encountered in coal-fired power plants. To understand its formation mechanism, six samples of the deposit were collected from different positions of boiler in the Zhuzhou coal-fired power plant in Hunan of China. The mineralogical, chemical compositions, and microstructure of ash samples were analyzed by X-ray diffraction spectrometry (XRD), X-ray fluorescence spectrometry (XRF), optical microscopy, and field scanning electron microscopy equipped with energy dispersive X-ray spectrometry (FSEM-EDX). The results show that the deposits were mainly composed of silica amorphous phases and their chemical compositions of different layers significantly varied. The identified minerals include mullite, cristobalite, hematite, quartz, hercynite, and anorthite. The silica-rich glass phases are derived from volatilization-recondensation of SiO and the interaction between aluminosilicates and other minerals. Several types of crystals were identified in the deposits, including iron-oxide crystals, Fe-Ca-bearing phase, Si-rich phase, and aluminosilicate phase. The deposition of crystals as well as the following melting is the main reason for the porosity structure of deposit. The interaction and eutectic of minerals in coal led to the serious deposition in the coal-fired power plant. (author)

  18. Design and implementation of a field pilot study on using coal fly ash to prevent oxidation of reactive mine tailings

    International Nuclear Information System (INIS)

    This paper reported on a pilot scale study that investigated the feasibility of using coal fly ash in mine tailings management and acid mine drainage (AMD) treatment at Goldcorp's Musselwhite Mine site in northern Ontario. The principles and key aspects of the fly ash application in mine tailings management were described. Fly ash from the Atikokan coal-fired power generating plant was added to the Musselwhite tailings as a mixture as well as intermediate and top layers. The physical, chemical and hydrogeological effects of the two approaches were monitored. The paper provided details of the design, implementation, monitoring, sampling and testing over 2 years. The objectives were to evaluate the optimum mass ratio of coal fly ash and mine tailings, effectiveness in reducing the infiltration of precipitation, and projected long-term durability and performance on tailings oxidation prevention. The pilot study was designed based on the principles of cementitious materials formation and secondary mineral formation by the reactions of coal fly ash and water/AMD. Calcium oxide, aluminum oxide, silicon oxide, and ferric oxide are major components of coal fly ash. The preliminary test results revealed that water did not accumulate and cracks did not form on top of 4 tanks. The settlements of the mixing approaches were lower than that of the stratified approach and the temperature distributions in the 4 tanks were comparable. 9 refs., 3 tabs., 11 figs.

  19. 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.

  20. Investigation and measurement of ash content of coal in Zirab coal Mine-Iran using dual energy γ-ray and x-ray fluorescence methods

    International Nuclear Information System (INIS)

    Coal with low ash content has an important role in the coal and steel industry. There are different methods to measure the ash content. The conventional method which is used in most coal mines of Iran, is to burn the coal and measure the remaining ash. A new method has been recently developed at Nuclear Research Center of Iran, which works on the basis of the ob sorption of the dual energy γ-ray by coal. In this paper we present the results obtained from coal mine Zirab, Central Alborz, Iranto which we have applied this method, and compared the results with those obtained by the conventional method. In addition, the chemical components of the coal samples from six layers of this mine was obtained by X-ray fluorescence. We have found that for SiO2, Al2O3, TiO2, Na2O and K2O there exists a linear relationship between these components and the ash content, but such a relationship was not obtained for Fe2O3, Ca O, SO3 and Mg O

  1. 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.

  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; Wedel, Stig; Dam-Johansen, Kim

    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 to...

  3. 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.

  4. Primary investigation of a design for a dual energy gamma-ray transmission gauge to determine the ash content of coal on a conveyor belt

    International Nuclear Information System (INIS)

    In order to design a dual energy ?-ray transmission gauge for measuring, on-line, the ash content of coal, an investigation was carried out to determine the relation between the theoretical mass absorption coefficient (?-bar) and the % ash of coal in the Kerman District Coal Mines. Because coal, transported on a conveyor belt, may be a non-homogeneous mixture from one or more mines, it was decided to compare % ash in a mixture of coals from several mines with that from individual mines, the measurements being made whilst the coal was being transported on a conveyor belt. The investigation shows that the relation between the mass absorption coefficient and the % ash in a coal mixture from several mines cannot be used to assess, accurately, the value of ?-bar for coals from individual mines in this particular region. (author)

  5. Revegetation on a coal fine ash disposal site in South Africa

    Energy Technology Data Exchange (ETDEWEB)

    Van Rensburg, L.; De Sousa Correia, R.I.; Booysen, J. [Potchefstroom Univ. for Christian Higher Education (South Africa). Research Inst. for Reclamation Ecology; Ginster, M. [Sastech Research and Development, Sasolburg (South Africa)

    1998-11-01

    Eight medium amendments were conducted on top of a fine ash coal dump (i) to evaluate a few cost-effective treatments that could determine the minimum fertility status required for the local ash to support the establishment of a viable vegetation cover, and (ii) to select suitable grass species that would establish on the ash and could serve as a foundation for long-term rehabilitation. Degree and success of grass establishment per medium amelioration treatment is expressed in terms of total biomass, percentage basal cover, and in terms of a condition assessment model. Both the chemical and physical nature of the ash medium before and after amendment was characterized, as were the concentrations of some essential and potentially toxic elements in leaf samples. In terms of medium amelioration 5000 kg ha{sup {minus}1} compost, or 500 kg ha{sup {minus}1} kraal manure or 480 kg 2:3:2 ha{sup {minus}1} proved to be most effective. The grass species that occurred with the highest frequency, irrespective of treatment, were the perennials bermudagrass [Cynodon dactylon (L.) pers. var dactylon], weeping lovegrass [Eragrostis curvula (Schrader) Nees], and the annual teff [Eragrostis tef (Zuccagni) Trotter]. Of the potentially toxic extractable metals monitored in the leaves of vegetation on the dump, only Se accumulated to an average level of 4.4 mg kg{sup {minus}1} that could be toxic to livestock.

  6. 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.

  7. Dissolution of Rare Earth Elements from Coal Fly Ash Particles in a Dilute H2SO4 Solvent

    OpenAIRE

    Shunsuke Kashiwakura; Yuichi Kumagai; Hiroshi Kubo; Kazuaki Wagatsuma

    2013-01-01

    Recently, the worldwide supply of rare earth element (REE) resources will be severely restricted. On the other hand, coal fly ash particles emitted from coal-fired electric power plants contain relatively high concentrations of REEs. The contents of REEs in coal fly ash are regularly several hundreds of ppmw. In order to extract and recover REEs from coal fly ash particles, as a first step, we have investigated their dissolution behavior in a dilute H2SO4 solvent. The REE content of coal fly...

  8. Evaluation of ash deposits during experimental investigation of co-firing of Bosnian coal with wooden biomass

    Energy Technology Data Exchange (ETDEWEB)

    Smajevic, Izet; Kazagic, Anes [JP Elektroprivreda BiH d.d., Sarajevo (Bosnia and Herzegovina); Sarajevo Univ. (Bosnia and Herzegovina). Faculty of Mechanical Engineering

    2008-07-01

    The paper is addressed to the development and use different criteria for evaluation of ash deposits collected during experimental co-firing of Bosnian coals with wooden biomass. Spruce saw dust was used for the co-firing tests with the Kakanj brown coal and with a lignite blend consisted of the Dubrave lignite and the Sikulje lignite. The coal/biomass mixtures at 93:7 %w and at 80:20 %w were tested. Experimental lab-scale facility PF entrained flow reactor is used for the co-firing tests. The reactor allows examination of fouling/slagging behaviors and emissions at various and infinitely variable process temperature which can be set at will in the range from ambient to 1560 C. Ash deposits are collected on two non-cooled ceramic probes and one water-cooled metal surface. Six different criteria are developed and used to evaluate behavior of the ash deposits on the probes: ash deposit shape, state and structure, which are analyzed visually - photographically and optically by a microscope, rate of adhesion and ash deposit strength, analyzed by physic acting to the ash deposits, and finally deposition rate, determined as a mass of the deposit divided by the collecting area and the time of collecting. Furthermore, chemical composition analysis and AFT of the ash deposits were also done to provide additional information on the deposits. (orig.)

  9. Brick manufacture with fly ash from Illinois coals. Quarterly report, 1 December 1994--28 February 1995

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, R.E.; Dreher, G.; Frost, J.; Moore, D.; Rostam-Abadi, M. [Illinois State Geological Survey, Urbana, IL (United States); Fiocchi, T. [Illinois Power Co., Decatur, IL (United States); Swartz, D. [Colonial Brick Co. (United States)

    1995-12-31

    This investigation seeks to utilize fly ash in fired-clay products such as building and patio bricks, ceramic blocks, field and sewer tile, and flower pots. This goal is accomplished by (1) one or more plant-scale, 5000-brick tests with fly ash mixed with brick clays at the 20% or higher level; (2) a laboratory-scale study to measure the firing reactions of a range of compositions of clay and fly ash mixtures; (3) a preliminary study to evaluate the potential environmental and economic benefits of brick manufacture with fly ash. Bricks and feed materials will be tested for compliance with market specifications and for leachability of pollutants derived from fly ash. The laboratory study will combine ISGS databases, ICCI-supported characterization methods, and published information to improve predictions of the firing characteristics of Illinois fly ash and brick clay mixtures. Because identical methods are used to test clay firing and coal ash fusion, and because melting mechanisms are the same, improved coal ash fusion predictions are an additional expected result of this research. If successful, this project should convert a disposal problem (fly ash) into valuable products-bricks. During this quarter we set up the manufacturing run at Colonial Brick Co., finalized arrangements for a larger brick manufacturing run at Marseilles Brick Co. in YR2, revised our laboratory procedures for selective dissolution analysis, obtained information to select three standard fly ashes, and continued our characterization of brick clays that could be mixed with fly ash for fired-clay products. Due to delays in other areas, we began construction of the optimization program for year 2. We discovered recently that fly ash dust will be an unanticipated problem at the brick plant.

  10. An urgent need for an EPA standard for disposal of coal ash

    International Nuclear Information System (INIS)

    EPA, the White House, and electric utilities are stalled in a struggle over a proposed new rule on coal ash disposal. Although this rule is long overdue, EPA now stands on the cusp of bringing forward a landmark decision that could benefit aquatic resources in the USA for decades to come and also set an important regulatory leadership example for the international community to follow. However, multi-million dollar wildlife losses are continuing to pile up as things stall in Washington. In this commentary I use a newly reported example, Wildlife Damage Case 23, to further illustrate serious flaws in the National Pollutant Discharge Elimination System that EPA's new rule can address. Case 23 provides additional impetus for EPA and the White House to move swiftly and decisively to end surface impoundment disposal of coal ash and the associated toxic impacts to wildlife. - Wildlife poisoning from coal combustion waste shows how regulatory policy is influenced by politics and industry rather than prudent decisions based on credible scientific investigation

  11. 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)

  12. Utilization of zeolites synthesized from coal fly ash for the purification of acid mine waters

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, N.; Querol, X.; Ayora, C.; Pereira, C.F.; Janssen-Jurkovicova, M. [CSIC, Barcelona (Spain). Inst. of Earth Sciences ' Jaume Almera'

    2001-09-01

    Two pilot plant products containing 65 and 45% NaP1 zeolite were obtained from two Spanish coal fly ashes (Narcea and Teruel Power Station, respectively). The zeolitic product obtained showed a cation exchange capacity (CEC) of 2.7 and 2.0 mequiv/g, respectively. Decontamination tests of three acid mine waters from southwestern Spain were carried out using the zeolite derived from fly ash and commercial synthetic zeolite. The results demonstrate that the zeolitic material could be employed for heavy metal uptake in the water purification process. Doses of 5-30 g of zeolite/L have been applied according on the zeolite species and the heavy metal levels. Moreover, the application of zeolites increases the pH. This causes metal-bearing solid phases to precipitate and enhances the efficiency of the decontamination process. 31 refs., 4 figs., 5 tabs.

  13. 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.

  14. Mineralogy, chemical composition, and microstructure of ferrospheres in fly ashes from coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Yongchun Zhao; Junying Zhang; Junmin Sun; Xiangfei Bai; Chuguang Zheng [Huazhong University of Science and Technology, Wuhan (China). State Key Laboratory of Coal Combustion

    2006-08-15

    Fourteen samples of coal and ferrospheres, which were recovered by dry magnetic separation from fly ashes, were collected from five power plants in China. The mineralogy, chemical composition, and microstructure of ferrospheres in fly ashes have been studied by optical microscopy, X-ray diffraction (XRD), Moessbauer spectroscopy, and field emission scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (FSEM-EDX). Iron in ferrospheres mainly occurs as Fe{sub 3}O{sub 4}, {alpha}Fe{sub 2}O{sub 3}, {gamma}Fe{sub 2}O{sub 3}, MgFe{sub 2}O{sub 4}, and Fe{sup 3+}-glass, ferrian spinel, and so on. On the basis of iron content, the ferrospheres in fly ashes are classified into four groups, namely ferrooxides, aluminosilicate-bearing ferrooxides, high-ferriferous aluminosilicates, and ferroaluminosilicates . Ferrooxides are derived from the oxidation of iron-bearing minerals, whereas aluminosilicate-bearing ferrooxides, high-ferriferous aluminosilicates, and ferroaluminosilicates are formed by the fusion of different proportions of inherent iron-bearing minerals and clay minerals. According to their microstructure, the ferrospheres in fly ashes are classified into seven groups, namely sheet ferrospheres, dendritic ferrospheres, granular ferrospheres, smooth ferrospheres, ferroplerospheres, porous ferrospheres, and molten drop ferrospheres. Sheet ferrospheres are derived from the oxidation of iron-bearing minerals immediately; smooth ferrospheres, molten drop ferrospheres, ferroplerospheres, and porous ferrospheres are the complex eutectic of inherent iron-bearing minerals and clay minerals; dendritic ferrospheres and granular ferrospheres are formed by the conglutination after the oxidation of iron-bearing minerals. Ferrooxides and aluminosilicate-bearing ferrooxides are important sources of the initial layer that occurs in deposits formed in coal-burning systems. 78 refs., 11 figs., 4 tabs.

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

    International Nuclear Information System (INIS)

    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 oC) 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 fuer 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 oC) compressive strength values about 60 MPa when the fly ash glass content was higher than 90%

  16. 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 degrees C) compressive strength values about 60 MPa when the fly ash glass content was higher than 90%. PMID:18006153

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

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez-Ayuso, E. [Department of Environmental Geology, Institute of Earth Sciences ' Jaume Almera' (CSIC), C/Lluis Sole i Sabaris s/n, 08028 Barcelona (Spain)], E-mail: ealvarez@ija.csic.es; Querol, X.; Plana, F.; Alastuey, A.; Moreno, N.; Izquierdo, M.; Font, O.; Moreno, T.; Diez, S. [Department of Environmental Geology, Institute of Earth Sciences ' Jaume Almera' (CSIC), C/Lluis Sole i Sabaris s/n, 08028 Barcelona (Spain); Vazquez, E.; Barra, M. [Department of Construction Engineering, Politechnical University of Catalonia, C/Jordi Girona 1-3, 08034 Barcelona (Spain)

    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 {sup o}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 fuer 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 {sup o}C) compressive strength values about 60 MPa when the fly ash glass content was higher than 90%.

  18. 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

  19. 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)

  20. 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-PC ashes, appeared to be important for the mercury adsorption. ?? 2007 American Chemical Society.

  1. Quantitative geochemical modelling using leaching tests: Application for coal ashes produced by two South African thermal processes

    International Nuclear Information System (INIS)

    The present work focuses on the reactivity of coal fly ash in aqueous solutions studied through geochemical modelling. The studied coal fly ashes originate from South African industrial sites. The adopted methodology is based on mineralogical analysis, laboratory leaching tests and geochemical modelling. A quantitative modelling approach is developed here in order to determine the quantities of different solid phases composing the coal fly ash. It employs a geochemical code (PHREEQC) and a numerical optimisation tool developed under MATLAB, by the intermediate of a coupling program. The experimental conditions are those of the laboratory leaching test, i.e. liquid/solid ratio of 10 L/kg and 48 h contact time. The simulation results compared with the experimental data demonstrate the feasibility of such approach, which is the scope of the present work. The perspective of the quantitative geochemical modelling is the waste reactivity prediction in different leaching conditions and time frames. This work is part of a largest research project initiated by Sasol and Eskom companies, the largest South African coal consumers, aiming to address the issue of waste management of coal combustion residues and the environmental impact assessment of coal ash disposal on land.

  2. Quantitative geochemical modelling using leaching tests: application for coal ashes produced by two South African thermal processes.

    Science.gov (United States)

    Hareeparsad, Shameer; Tiruta-Barna, Ligia; Brouckaert, Chris J; Buckley, Chris A

    2011-02-28

    The present work focuses on the reactivity of coal fly ash in aqueous solutions studied through geochemical modelling. The studied coal fly ashes originate from South African industrial sites. The adopted methodology is based on mineralogical analysis, laboratory leaching tests and geochemical modelling. A quantitative modelling approach is developed here in order to determine the quantities of different solid phases composing the coal fly ash. It employs a geochemical code (PHREEQC) and a numerical optimisation tool developed under MATLAB, by the intermediate of a coupling program. The experimental conditions are those of the laboratory leaching test, i.e. liquid/solid ratio of 10 L/kg and 48 h contact time. The simulation results compared with the experimental data demonstrate the feasibility of such approach, which is the scope of the present work. The perspective of the quantitative geochemical modelling is the waste reactivity prediction in different leaching conditions and time frames. This work is part of a largest research project initiated by Sasol and Eskom companies, the largest South African coal consumers, aiming to address the issue of waste management of coal combustion residues and the environmental impact assessment of coal ash disposal on land. PMID:21208742

  3. Sequential leaching behaviour of some elements during chemical treatment of ceramic censorship from coal fly ash

    International Nuclear Information System (INIS)

    The extractable contents of Ca, Cr, Cu, Fe, Mg, Mn, Ni, Pb, and Zn were determined using a six-stage sequential leaching procedure to isolate: (1) water-soluble; (2) slightly changed organic matter; (3) carbonate; (4) Fe-Mn oxides; (5) glass and silicates; and (6) char fractions; of ceramic cenospheres (CCs) recovered from coal fly ash (FA). The leaching behaviour and modes of occurrence of the above-listed elements in CCs are discussed. The results show that this improved sequential leaching procedure applied on well characterized chemically and mineralogically CCs is promising and could be successfully used. (authors)

  4. Potential Use of Malaysian Thermal Power Plants Coal Bottom Ash in Construction

    OpenAIRE

    Abdulhameed Umar Abubakar; Khairul Salleh Baharudin

    2012-01-01

    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 i...

  5. 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 fluxes in the experimental plots under different wind speeds (5 to 9 m s-2) showed significant differences in favor of the treatment of coal fly-ash + biocrusts inoculum, compared to the controls (sand, sand + biocrusts and sand + coal fly-ash).

  6. Mineral sequestration of CO2 by aqueous carbonation of coal combustion fly-ash

    OpenAIRE

    Montes-Hernandez, G.; Perez-Lopez, R. (Rosa); Renard, F.; Nieto, J.-M.; Charlet, L.

    2008-01-01

    The increasing CO2 concentration in the Earth's atmosphere, mainly caused by fossil fuel combustion, has led to concerns about global warming. A technology that could possibly contribute to reducing carbon dioxide emissions is the in-situ mineral sequestration (long term geological storage) or the ex-situ mineral sequestration (controlled industrial reactors) of CO2. In the present study, we propose to use coal combustion fly-ash, an industrial waste that contains about 4.1 wt.% of lime (CaO)...

  7. Evaluation of radioactivity levels of coal, slag and fly ash samples used in Giresun province of Turkey

    International Nuclear Information System (INIS)

    In present work natural radionuclides activities (236Ra, 232Th and 40K) of the different types of coal, slag and fly ash samples used in Giresun province (Eastern Black Sea region of Turkey) were measured by using gamma-ray spectrometry. These samples were collected as homogeneously and separately around Giresun province. The mean activity concentrations of 226Ra, 232Th and 40K radionuclides in coal, slag and fly ash samples were found as 107, 67 and 440 Bg.Kg-1 for coal; 59, 25 and 268 Bg.kg-1 for slag and 136, 60 and 417 Bg.kg-1 for fly ash samples, respectively. To estimate health effect due to the aforementioned radionuclides, absorbed dose rates and annual effective doses have been calculated. These values were evaluated and compared with the internationally recommended values

  8. Quantitative evaluation of minerals in fly ashes of biomass, coal and biomass-coal mixture derived from circulating fluidised bed combustion technology

    International Nuclear Information System (INIS)

    The chemical and mineralogical composition of fly ash samples collected from laboratory scale circulating fluidised bed (CFB) combustion facility have been investigated. Three fly ashes were collected from the second cyclone in a 50 kW laboratory scale boiler, after the combustion of different solid fuels. Characterisation of the fly ash samples was conducted by means of X-ray fluorescence (XRF), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Quantitative analysis of the crystalline (mineral) and amorphous phases in each ash sample was carried out using the Rietveld-based Siroquant system, with an added spike of ZnO to evaluate the amorphous content. SiO2 is the dominant oxide in the fly ashes, with CaO, Al2O3 and Fe2O3 also present in significant proportions. XRD results show that all three fly ashes contain quartz, anhydrite, hematite, illite and amorphous phases. The minerals calcite, feldspar, lime and periclase are present in ashes derived from Polish coal and/or woodchips. Ash from FBC combustion of a Greek lignite contains abundant illite, whereas illite is present only in minor proportions in the other ash samples.

  9. Quantitative evaluation of minerals in fly ashes of biomass, coal and biomass-coal mixture derived from circulating fluidised bed combustion technology

    Energy Technology Data Exchange (ETDEWEB)

    Koukouzas, N.; Ward, C.R.; Papanikolaou, D.; Li, Z.S.; Ketikidis, C. [Institute of Solid Fuels Technology & Applications, Athens (Greece)

    2009-09-15

    The chemical and mineralogical composition of fly ash samples collected from laboratory scale circulating fluidised bed (CFB) combustion facility have been investigated. Three fly ashes were collected from the second cyclone in a 50 kW laboratory scale boiler, after the combustion of different solid fuels. Characterisation of the fly ash samples was conducted by means of X-ray fluorescence (XRF), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Quantitative analysis of the crystalline (mineral) and amorphous phases in each ash sample was carried out using the Rietveld-based Siroquant system, with an added spike of ZnO to evaluate the amorphous content. SiO{sub 2} is the dominant oxide in the fly ashes, with CaO, Al{sub 2}O{sub 3} and Fe{sub 2}O{sub 3} also present in significant proportions. XRD results show that all three fly ashes contain quartz, anhydrite, hematite, illite and amorphous phases. The minerals calcite, feldspar, lime and periclase are present in ashes derived from Polish coal and/or woodchips. Ash from FBC combustion of a Greek lignite contains abundant illite, whereas illite is present only in minor proportions in the other ash samples.

  10. Quantitative evaluation of minerals in fly ashes of biomass, coal and biomass-coal mixture derived from circulating fluidised bed combustion technology

    Energy Technology Data Exchange (ETDEWEB)

    Koukouzas, Nikolaos, E-mail: koukouzas@certh.gr [Centre for Research and Technology Hellas, Institute for Solid Fuels Technology and Applications, Mesogeion Ave. 357-359, 15231 Halandri, Athens (Greece); Ward, Colin R. [School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052 (Australia); Papanikolaou, Dimitra [Centre for Research and Technology Hellas, Institute for Solid Fuels Technology and Applications, Mesogeion Ave. 357-359, 15231 Halandri, Athens (Greece); Li, Zhongsheng [School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052 (Australia); Ketikidis, Chrisovalantis [Centre for Research and Technology Hellas, Institute for Solid Fuels Technology and Applications, Mesogeion Ave. 357-359, 15231 Halandri, Athens (Greece)

    2009-09-30

    The chemical and mineralogical composition of fly ash samples collected from laboratory scale circulating fluidised bed (CFB) combustion facility have been investigated. Three fly ashes were collected from the second cyclone in a 50 kW laboratory scale boiler, after the combustion of different solid fuels. Characterisation of the fly ash samples was conducted by means of X-ray fluorescence (XRF), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Quantitative analysis of the crystalline (mineral) and amorphous phases in each ash sample was carried out using the Rietveld-based Siroquant system, with an added spike of ZnO to evaluate the amorphous content. SiO{sub 2} is the dominant oxide in the fly ashes, with CaO, Al{sub 2}O{sub 3} and Fe{sub 2}O{sub 3} also present in significant proportions. XRD results show that all three fly ashes contain quartz, anhydrite, hematite, illite and amorphous phases. The minerals calcite, feldspar, lime and periclase are present in ashes derived from Polish coal and/or woodchips. Ash from FBC combustion of a Greek lignite contains abundant illite, whereas illite is present only in minor proportions in the other ash samples.

  11. Quantitative evaluation of minerals in fly ashes of biomass, coal and biomass-coal mixture derived from circulating fluidised bed combustion technology.

    Science.gov (United States)

    Koukouzas, Nikolaos; Ward, Colin R; Papanikolaou, Dimitra; Li, Zhongsheng; Ketikidis, Chrisovalantis

    2009-09-30

    The chemical and mineralogical composition of fly ash samples collected from laboratory scale circulating fluidised bed (CFB) combustion facility have been investigated. Three fly ashes were collected from the second cyclone in a 50 kW laboratory scale boiler, after the combustion of different solid fuels. Characterisation of the fly ash samples was conducted by means of X-ray fluorescence (XRF), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Quantitative analysis of the crystalline (mineral) and amorphous phases in each ash sample was carried out using the Rietveld-based Siroquant system, with an added spike of ZnO to evaluate the amorphous content. SiO(2) is the dominant oxide in the fly ashes, with CaO, Al(2)O(3) and Fe(2)O(3) also present in significant proportions. XRD results show that all three fly ashes contain quartz, anhydrite, hematite, illite and amorphous phases. The minerals calcite, feldspar, lime and periclase are present in ashes derived from Polish coal and/or woodchips. Ash from FBC combustion of a Greek lignite contains abundant illite, whereas illite is present only in minor proportions in the other ash samples. PMID:19410365

  12. Fly ash formation and sulphation during the combustion of brown coal

    Energy Technology Data Exchange (ETDEWEB)

    Domazetis, G.; Lovelace, P. (State Electricity Commission of Victoria, Melbourne, Vic. (Australia))

    1988-02-01

    This report deals with the extension of the NERDDP project 'Fly Ash Formation and Sulphation during the combustion of Brown Coal', completed in 1987, and describes improvements in the computer code SCCOFF, which simulates the chemical kinetics of brown coal combustion. Modification of SCCOFF has improved its user interface, allowed time-temperature profiles and constant pressure conditions to be included in SCCOFF's numerical integration routines, calculates sulphuric acid dewpoints, and combustion heat relase profiles. A sensitivity analysis of hypothetical sodium silicate reactions has been carried out. The results show that the extent and rate of formation of sodium silicate is not critically dependent on the rate constants of the proposed reaction scheme. The formation of sodium sulphate however, shows great sensitivity to the rate of sodium silicate formation. It is planned to produce an engineering version of SCCOFF. This can be accomplished through collaboration with research groups in the United States.

  13. Preparation of Active Absorbent for Flue Gas Desulfurization From Coal Bottom Ash: Effect of Absorbent Preparation Variables

    OpenAIRE

    Chang Chin Li, Lee Keat Teong, Subhash Bhatia and Abdul Rahman Mohamed

    2012-01-01

    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-Tel...

  14. Oxidation of brown coal humic acids by potassium permanganate in an alkaline medium

    Energy Technology Data Exchange (ETDEWEB)

    Shishkov, V.F.; Verkhodanova, N.N.; Seredkova, S.V.; Lemzyakov, V.P.; Tuturina, V.V.

    1986-01-01

    Methylated and nonmethylated brown coal humic acids are investigated with the help of infrared spectroscopy and by oxidation with potassium permanganate in an alkaline medium. The paper studies changes of oxygen-containing groups in humic acids during methylation (phenol and alcohol hydroxyl, carbonyl and carboxyl groups) and the effect of blocking parts of the functional group (carbonyl and phenol hydroxyl) on the composition and emission of oxidation products. Character of oxygen-containing functional groups of methylated and nonmethylated humic acids and the comparative oxidation are analyzed in order to obtain data on structure and composition of brown coal components. The paper gives chemical properties of brown coal; elemental and functional composition of humic acids; infrared spectra of methylated and nonmethylated humic acid; composition of volatile acids, aliphatic, dicarboxylic and aromatic acids. Oxidation of methylated and nonmethylated humic acids was carried out in similar conditions at room temperature. Separation and analysis of oxidation products were made using a method developed for sapropelites. 9 references.

  15. Phase diagram approach to the fluxing effect of additions of CaCO{sub 3} on Australian coal ashes

    Energy Technology Data Exchange (ETDEWEB)

    Hurst, H.J.; Novak, F.; Patterson, J.H. [CSIRO, North Ryde, NSA (Australia). Division of Coal and Energy Technology

    1996-11-01

    This paper presents a phase diagram approach to predict the melting temperatures of coal ash/flux mixtures and the viscosity versus temperature characteristics of the molten slags. This is illustrated by calcium oxide fluxing studies of three Australian bituminous coal ashes covering a range of silica to alumina ratios. Reasonable agreement was obtained between the observed melting temperatures of the calcium oxide/coal ash mixtures and predictions based on equilibrium phase diagrams for the ternary system silica, alumina, and calcium oxide or for the quaternary system silica, alumina, calcium oxide, and ferrous oxide. The approach is supported by energy dispersive scanning electron microscopy (SEM), SEM microprobe, and X-ray diffraction (XRD) studies of the slags. Slag viscosity measurements were made with a rotational viscometer over the range 1200-1600{degree}C. The measured viscosities were compared with predicted values using a model based on experimental results for the ternary system silica, alumina, and calcium oxide. The agreement between experimental results and predictions from this approach suggests that sensible estimates can be made of the amount of fluxing agent necessary for satisfactory slag tapping from the ash content and ash composition of the coal. 25 refs., 3 figs., 4 tabs.

  16. Presumption of use for fly ash in alkali activation

    International Nuclear Information System (INIS)

    In recent years, increasingly comes fly ash from energy industry into the forefront of many research institutes. This is due mainly by effort to take advantage of a huge quantity of fly ash and transform it into a promising material that could replace the natural resources. One of the newest areas dealing with the use of fly ash is alkaline activation, which can bring a whole new perspective on this material and its use. Due to mineralogical composition of coal can be used residues of aluminosilicate, which are contained in fly ash. An important factor is the nature of the present crystalline aluminosilicates, which is determined by the parameters of the combustion process and largely decides the reactivity of fly ash. Therefore, in this article will be described the main prerequisites for the utilization of fly ash in alkaline alkalinisation, and these assumptions will be confronted with a sample of fly ash utilized for alkali activation. (Authors)

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

    Directory of Open Access Journals (Sweden)

    Menéndez, E.

    2013-12-01

    Full Text Available 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.La eliminación de subproductos del carbón supone problemas ambientales y económicos en todo el mundo por lo que la reutilización y valorización de los mismos se ha convertido en un tema importante en las últimas décadas. Mientras que las cenizas volantes se han utilizado en aplicaciones de alto valor y se han desarrollado productos de construcción en los que se ha utilizado esta ceniza como adición al cemento, no se ha sido permitido la utilización de la ceniza de fondo como en cementos. Este artículo examina las propiedades químicas y físicas de las cenizas volantes y de fondo procedentes de dos centrales termoeléctricas con el objetivo de compararlas y analizar la potencial utilización de la ceniza de fondo como adición al cemento. Se han estudiado también las propiedades mecánicas de morteros de cemento fabricados con distintos porcentajes de ambas cenizas como sustitución del cemento. Los resultados obtenidos mostraron que las ambos tipos de cenizas tenían una composición química similar. Los valores de resistencia a compresión a 28 días de los morteros con un 10 % y 25 % de porcentaje de sustitución estaban dentro de los límites permitidos en la normativa Europea y no había diferencias significativas entre las cenizas volantes y de fondo procedentes de ambas centrales térmicas.

  18. 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.

  19. A study of the correlation between ash content and natural radionuclide content in hard coals from northern Spain

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez Alvarez, M.C.; Dopico Vivero, M.T.; Amengual, P.A. (Universidad de Oviedo, Oviedo (Spain). Lab. de Ingenieria Nuclear)

    Thirty-five hard coal samples from four coal washing plants in the regions of Asturias and Leon (an important mining area in Northern Spain) were analyzed for ash content and natural radionuclide content ([sup 238]U,[sup 40]K,[sup 232]Th). A correlation between ash contents and natural radionuclide content was established as simple and multiple regression. The correlation coefficients (r) are greater than 0.92 in all cases. The mean absolute error range was 1.3-2.6 and its standard deviation range was 1.3-2.0. 8 refs., 6 figs.

  20. 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.

  1. 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.

  2. Precipitation of heavy metals from coal ash leachate using biogenic hydrogen sulfide generated from FGD gypsum.

    Science.gov (United States)

    Jayaranjan, Madawala Liyanage Duminda; Annachhatre, Ajit P

    2013-01-01

    Investigations were undertaken to utilize flue gas desulfurization (FGD) gypsum for the treatment of leachate from the coal ash (CA) dump sites. Bench-scale investigations consisted of three main steps namely hydrogen sulfide (H(2)S) production by sulfate reducing bacteria (SRB) using sulfate from solubilized FGD gypsum as the electron acceptor, followed by leaching of heavy metals (HMs) from coal bottom ash (CBA) and subsequent precipitation of HMs using biologically produced sulfide. Leaching tests of CBA carried out at acidic pH revealed the existence of several HMs such as Cd, Cr, Hg, Pb, Mn, Cu, Ni and Zn. Molasses was used as the electron donor for the biological sulfate reduction (BSR) process which produced sulfide rich effluent with concentration up to 150 mg/L. Sulfide rich effluent from the sulfate reduction process was used to precipitate HMs as metal sulfides from CBA leachate. HM removal in the range from 40 to 100% was obtained through sulfide precipitation. PMID:23168629

  3. New fertilizer utilizing coal ash. ; Extragreen chemical fertilizer. Sekitanbai wo riyoshita shinhiryo. ; Extra green kasei hiryo

    Energy Technology Data Exchange (ETDEWEB)

    1993-10-01

    This paper describes the results of culturing tests on different kinds of vegetables using the Extragreen fertilizer (a new fertilizer) that utilizes coal ash. The new fertilizer consists of aqueous phosphoric acid solution mixed uniformly with such fertilizer materials as nitrogen, phosphoric acid and potassium, and then mixed with coal ash so that it solidifies naturally. As a result of comparative discussions with fertilizers having been used by farmers, the use of the new fertilizer resulted in yield increase by 10% to several ten percent in cabbage, white radish, taro, and Chinese yam, and several percent to 10% in Chinese cabbage and paddy rice. With regard to quality, leaf vegetables such as cabbage had slow fresh weight reduction rate after harvest, with long lasting freshness. Root vegetables such as white radish, potato, Chinese yam, and sweet potato had their sweetness increased and their colors retained fresher, raising their commercial value. The present fertilizer showed a trend of reducing such continuous cropping injuries (soil diseases) as the root-knot disease in cabbage, the powder scab in potato, and the brown rots and root rots in Chinese yam. 5 figs.

  4. 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

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. Production of cements from Illinois coal ash. Final technical report, September 1, 1995--August 31, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, J.C.; Bhatty, J.L.; Mishulovich, A.

    1997-05-01

    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. 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. Since the residues are used as an integral component of the cement and not just as additives to concrete, larger amounts of the residues can be utilized. The process uses submerged combustion to melt blends of coal combustion residues with lime, clay, and/or sand. The submerged combustion melter utilizes natural gas-oxidant firing directly into a molten bath to provide efficient melting of mineral-like materials. Use of this melter for cement production has many advantages over rotary kilns including very little, if any, grinding of the feed material, very low emissions, and compact size. During the first year of the program, samples of coal combustion residues were blended and mixed, as needed; with lime, clay, and/or sand to adjust the composition. Six mixtures, three with fly ash and three with bottom ash, were melted in a laboratory-scale furnace. The resultant products were used in mortar cubes and bars which were subjected to ASTM standard tests of cementitious properties. In the hydraulic activity test, mortar cubes were found to have a strength comparable to standard mortar cements. In the compressive strength test, mortar cubes were found to have strengths that exceeded ASTM blended cement performance specifications. In the ASR expansion test, mortar bars were subjected to alkali-silica reaction-induced expansion, which is a problem for siliceous aggregate-based concretes that are exposed to moisture. The mortar bars made with the products inhibited 85 to 97% of this expansion. These results show that residue-based products have an excellent potential as ASR-preventing additions in concretes.

  11. Distinguishing respirable quartz in coal fly ash using computer-controlled scanning electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Nick Cprek; Naresh Shah; Frank E. Huggins; Gerald P. Huffman [University of Kentucky, Lexington, KY (United States). Consortium for Fossil Fuel Science and Department of Chemical and Materials Engineering

    2007-05-15

    Determination and classification of quartz in coal fly ash (CFA) is a subject of interest because of the adverse health effects caused by inhalation of crystalline silica. Workers with prolonged exposure to this carcinogen can develop respiratory diseases over time. This obviously may include utility plant workers involved in the handling, loading, and hauling of CFA. In this investigation, computer-controlled scanning electron microscopy (CCSEM) and X-ray diffraction (XRD) were used to investigate Si-rich phases in CFA to develop a better approach for the determination of respirable quartz. Three CFA samples from utility boilers and a NIST glass standard CFA sample were investigated. The XRD measurements indicated that the four samples contained from 7.0 to 16.0 wt.% of quartz. The CCSEM measurements utilized both particle size distributions and a particle shape parameter, circularity, to classify the Si-rich phases in these ashes as either crystalline or amorphous (glass). The results indicated that the amount of free, respirable, quartz in these CFA samples ranged from only 0.1-1.0 vol % and showed little correlation with the XRD results for the bulk ash. These results are significant in view of the fact that XRD is the traditional method of measuring crystalline silica in dust collected from workplace atmospheres. The results provide a better understanding of studies that indicate very little evidence of a link between human exposure to CFA and silicosis and lung cancer. 24 refs., 8 figs., 4 tabs.

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

    Science.gov (United States)

    Lu, S G; Chen, Y Y; Shan, H D; Bai, S Q

    2009-09-30

    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 16.3wt%, 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. PMID:19380201

  13. Flue gas desulfurization gypsum and coal fly ash as basic components of prefabricated building materials.

    Science.gov (United States)

    Telesca, Antonio; Marroccoli, Milena; Calabrese, Daniela; Valenti, Gian Lorenzo; Montagnaro, Fabio

    2013-03-01

    The manufacture of prefabricated building materials containing binding products such as ettringite (6CaO·Al2O3·3SO3·32H2O) and calcium silicate hydrate (CSH) can give, in addition to other well-defined industrial activities, the opportunity of using wastes and by-products as raw materials, thus contributing to further saving of natural resources and protection of the environment. Two ternary mixtures, composed by 40% flue gas desulfurization (FGD) gypsum or natural gypsum (as a reference material), 35% calcium hydroxide and 25% coal fly ash, were submitted to laboratory hydrothermal treatments carried out within time and temperature ranges of 2h-7days and 55-85°C, respectively. The formation of (i) ettringite, by hydration of calcium sulfate given by FGD or natural gypsum, alumina of fly ash and part of calcium hydroxide, and (ii) CSH, by hydration of silica contained in fly ash and residual lime, was observed within both the reacting systems. For the FGD gypsum-based mixture, the conversion toward ettringite and CSH was highest at 70°C and increased with curing time. Some discrepancies in the hydration behavior between the mixtures were ascribed to differences in mineralogical composition between natural and FGD gypsum. PMID:23219474

  14. EVALUATION OF THE EFFECTS OF COAL FLY ASH AMENDMENTS ON THE TOXICITY OF A CONTAMINATED MARINE SEDIMENT

    Science.gov (United States)

    Burgess, Robert M.; Perron, Monique M.; Friedman, Carey L.; Suuberg, Eric M.; Pennell, Kelly G.; Cantwell, Mark G.; Pelletier, Marguerite C.; Ho, Kay T.; Serbst, Jonathan R.; Ryba, Stephan A.

    2013-01-01

    Approaches for cleaning-up contaminated sediments range from dredging to in situ treatment. In the present report, we discuss the effects of amending reference and contaminated sediments with coal fly ash to reduce the bioavailability and toxicity of a field sediment contaminated with polycyclic aromatic hydrocarbons (PAHs). Six fly ashes and a coconut charcoal were evaluated in 7 d whole sediment toxicity tests with a marine amphipod (Ampelisca abdita) and mysid (Americamysis bahia). Fly ashes with high carbon content and the coconut charcoal showed proficiency at reducing toxicity. Some of the fly ashes demonstrated toxicity in the reference treatments. It is suspected that some of this toxicity is related to the presence of ammonia associated with fly ashes as a result of post-oxidation treatment to reduce nitrous oxides emissions. Relatively simple methods exist to remove ammonia from fly ash prior to use and fly ashes with low ammonia content are available. Fly ashes were also shown to effectively reduce overlying water concentrations of several PAHs. There was no evidence of the release of the metals cadmium, copper, nickel or lead from the fly ashes. A preliminary 28 d polychaete bioaccumulation study with one of the high carbon fly ashes and a reference sediment was also performed. Although preliminary, there was no evidence of adverse effects to worm growth or lipid content, or the accumulation of PAHs or mercury from exposure to the fly ash. These data show fly ashes with high carbon contents may represent viable remedial materials for reducing the bioavailability of organic contaminants in sediments. PMID:18717615

  15. Application of leaching tests for toxicity evaluation of coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Tsiridis, V.; Samaras, P.; Kungolos, A.; Sakellaropoullos, G.P. [Technological Educational Institute for West Macedonia, Kozani (Greece). Dept. for Pollution Control Technology

    2006-08-15

    The toxic properties of coal fly ash samples obtained from various coal combustion power plants were evaluated in this work using physicochemical analyses and bioassays. Physicochemical analyses showed that heavy metals present in solid samples included Cr, Cu, Mn, Ni, Pb, and Zn. The results of the chemical analysis of eluates deduced by the application of standard leaching tests according to EN 12457-2 and Toxicity Characteristic Leaching Procedure (TCLP) methods indicated that the compounds contained in fly ashes could potentially be transferred to the liquid phase depending upon the leaching method used. Heavy metal concentrations were higher in TCLP eluates, indicating that the initial pH value of the leaching medium significantly affected the transfer of these elements to the liquid phase. Tests conducted with the photobacterium Vibrio fischeri (Microtox test), the crustacean Daphnia magna, and the rotifer Brachionus calyciflorus were used to assess toxicity of eluates obtained by both leaching tests. Daphnia magna was the most sensitive test organism. The EN 12457-2 method proved to be more reliable for toxicity evaluation of eluates. In contrast, the TCLP method showed some interference owing to acetic acid toxicity, and precipitation occurred after pH adjustment of eluates from acid to neutral range. The toxicity of both fly ashes and the corresponding solid leaching residues of EN 12457-2 and TCLP leaching tests was also measured using the Microtox Basic Solid phase Test. The results generated with this bioassay indicated that toxicity was greatly influenced by the pH status of the solid samples.

  16. Slag and ash chemistry after high-calcium lignite combustion in a pulverized coal-fired power plant

    OpenAIRE

    Papastergios, Georgios; Fernandez-Turiel, J. L.; Georgakopoulos, Andreas; Gimeno, D.

    2007-01-01

    More than 73% of the electrical power requirements of Greece are generated in lignite-fired power plants. Greece is the thirteenth largest coal and the fifth largest lignite producer in the world. The lack of domestic high-rank coals makes necessary to use low quality lignite for power generation in Greece. These lignites are characterized by a high water and ash content and a low calorific value. The low quality of such lignites generates important technical and environmental ...

  17. The impacts of alkaline mine drainage on ba, cr, ni, pb and zn concentration in the water resources of the takht coal mine, iran

    OpenAIRE

    Dahrazma, B; Kharghani, M

    2012-01-01

    The release of heavy metals into the environment represents one of the most important environmental effects involved in extracting coal; it needs to be studied more fully. The present research investigatedthe effects of coal-mining in an alkaline environment and alkaline mine drainage in the Takht coal mine regarding the distribution of selected heavy metals (Zn, Pb, Ni, Cr and Ba) on the region's surface andground water . The mine is located 12 Km southeast of Minoodasht, in Golestan provinc...

  18. The effect of oxygen-to-fuel stoichiometry on coal ash fine-fragmentation mode formation mechanisms.

    Energy Technology Data Exchange (ETDEWEB)

    Fix, G.; Seames, W. S.; Mann, M. D.; Benson, S. A.; Miller, D. J. (Materials Science Division); (Univ. of North Dakota)

    2011-04-01

    Ash particles smaller than 2.5 {micro}m in diameter generated during pulverized coal combustion are difficult to capture and may pose greater harm to the environment and human health than the discharge of larger particles. Recent research efforts on coal ash formation have revealed a middle fine-fragment mode centered around 2 {micro}m. Formation of this middle or fine-fragment mode (FFM) is less well understood compared to larger coarse and smaller ultrafine ash. This study is part of an overall effort aimed at determining the key factors that impact the formation of FFM. This work examined the effects of oxygen-to-fuel stoichiometry (OFS). Pulverized Illinois No.6 bituminous coal was combusted and the ash generated was size segregated in a Dekati low pressure inertial impactor. The mass of each fraction was measured and the ash was analyzed using scanning electron microscopy (SEM) and X-ray microanalysis. The FFM ash types were classified based on the SEM images to evaluate the significant fine-fragment ash formation mechanisms and determine any possible link between stoichiometry and formation mechanism. From the particle size distributions (PSDs), the coarse mode appears unaffected by the change in OFS, however, the OFS 1.05 lowered the fraction of ultrafine ash in relation to the higher OFS settings, and appears to increase the portion of the FFM. An intermediate minimum was found in the FFM at 1.3 {micro}m for the 1.20 and 1.35 OFS tests but was not observed in the 1.05 OFS. SEM analysis also suggests that OFS may contribute to changing formation mechanisms.

  19. 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 and ground waters

  20. Copper and cadmium adsorption on pellets made from fired coal fly ash

    International Nuclear Information System (INIS)

    Studies on the utilization of low cost adsorbents for removal of heavy metals from wastewaters are gaining attention. Fired coal fly ash, a solid by-product that is produced in power plants worldwide in million of tonnes, has attracted researchers' interest. In this work, fly ash was shaped into pellets that have diameter in-between 3-8 mm, high relative porosity and very good mechanical strength. The pellets were used in adsorption experiments for the removal of copper and cadmium ions from aqueous solutions. The effect of agitation rate, equilibration time, pH of solution and initial metal concentration were studied. The adsorption of both cations follows pseudo-second order kinetics reaching equilibrium after an equilibration time of 72 h. The experimental results for copper and cadmium adsorption fit well to a Langmuirian type isotherm. The calculated adsorption capacities of pellets for copper and cadmium were 20.92 and 18.98 mg/g, respectively. Desorption experiments were performed in several extraction media. The results showed that both metals were desorbed substantially from pellets under acidic solutions. For this reason, metal saturated pellets were encapsulated in concrete blocks synthesized from cement and raw pulverized fly ash in order to avoid metal desorption. The heavy metals immobilization after encapsulation in concrete blocks was tested through desorption tests in several aqueous media. The results showed that after 2 months in acidic media with pH 2.88 and 4.98 neither copper nor cadmium were desorbed thus indicating excellent stabilization of heavy metals in the concrete matrix. As a conclusion, the results showed that fly ash shaped into pellets could be considered as a potential adsorbent for the removal of copper and cadmium from wastewaters. Moreover, the paper proposes an efficient and simple stabilization process of the utilized adsorbents thus guarantying their safe disposal in industrial landfills and eliminating the risk of pollution for groundwater and other natural water receivers

  1. Assessment of coal and ash environmental impact with the use of gamma- and X-ray spectrometry

    International Nuclear Information System (INIS)

    Gamma-ray spectrometry (GS), energy dispersive X-ray fluorescence (EDXRF) analysis methods and wavelength dispersive X-ray fluorescence (WDXRF) were applied for the studies of some coal components, e.g., sulphur, light and heavy metal element concentrations and naturally occurring radioactive isotope contents. Hundred fifty coal samples originating mostly from eight different coal mines from Upper Silesian Coal Basin and 150 samples of ash obtained from these coal samples in laboratory by total combustion at final temperature of 820 deg C, were analyzed. Such comparative analyses can be helpful in selection of most suitable kind of coal for burning in electrical power and heat plants to minimize the environmental pollution. (author)

  2. 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 system provides a very promising future in designing effluent treatment systems

  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

    International Nuclear Information System (INIS)

    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. Characteristics and the behavior in electrostatic precipitators of high-alumina coal fly ash from the Jungar power plant, Inner Mongolia, China.

    Science.gov (United States)

    Qi, Liqiang; Yuan, Yongtao

    2011-08-15

    In China, flue gases emitted by coal-fired power plants are mainly cleaned using electrostatic precipitators (ESPs). However, based on observations, there is a decrease in the collection efficiency of ESPs in some power plants after burning Jungar coal in Inner Mongolia. In order to find the mechanism of coal fly ash escaping from ESPs, the size distribution, resistivity, and cohesive force of particulate matter samples from Jungar coal-fired power plants in China were measured using a Bahco centrifuge, a dust electrical resistivity test instrument, and a cohesive force test apparatus invented by the authors. Experiments were carried out to determine the chemical composition and current-voltage curve of fly ash under operating ESPs. The Al(2)O(3) content in fly ash was found to reach more than 50%, with the size distribution showing a higher content of PM2.5 and PM10 in high-alumina coal fly ash than in other coal fly ashes. The resistivity of high-alumina coal fly ash was recorded at over 10(12)Ω cm, but this did not result in a clear back corona. The cohesive force of high-alumina coal fly ash was very little. It was sensitive to smoke speed in the electric field, facilitating dust re-entrainment. PMID:21621327

  5. ANN-GA based optimization of a high ash coal-fired supercritical power plant

    International Nuclear Information System (INIS)

    Highlights: → Neuro-genetic power plant optimization is found to be an efficient methodology. → Advantage of neuro-genetic algorithm is the possibility of on-line optimization. → Exergy loss in combustor indicates the effect of coal composition on efficiency. -- Abstract: The efficiency of coal-fired power plant depends on various operating parameters such as main steam/reheat steam pressures and temperatures, turbine extraction pressures, and excess air ratio for a given fuel. However, simultaneous optimization of all these operating parameters to achieve the maximum plant efficiency is a challenging task. This study deals with the coupled ANN and GA based (neuro-genetic) optimization of a high ash coal-fired supercritical power plant in Indian climatic condition to determine the maximum possible plant efficiency. The power plant simulation data obtained from a flow-sheet program, 'Cycle-Tempo' is used to train the artificial neural network (ANN) to predict the energy input through fuel (coal). The optimum set of various operating parameters that result in the minimum energy input to the power plant is then determined by coupling the trained ANN model as a fitness function with the genetic algorithm (GA). A unit size of 800 MWe currently under development in India is considered to carry out the thermodynamic analysis based on energy and exergy. Apart from optimizing the design parameters, the developed model can also be used for on-line optimization when quick response is required. Furthermore, the effect of various coals on the thermodynamic performance of the optimized power plant is also determined.

  6. 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)

  7. The energy-water quality nexus: insights from the 2008 coal ash spill in Tennessee

    Science.gov (United States)

    Vengosh, A.; Ruhl, L.; Dwyer, G. S.; Hsu-Kim, H.; Deonarine, A.

    2010-12-01

    Energy production consumes a large volume of water. The USGS estimated that about 52 percent of the total USA fresh surface-water withdrawal in 2000 was for thermoelectric consumption (fresh water use ~188 for thermoelectric out of 563 billion cubic meters a year total water withdrawal in the USA). While water availability and possible changes induced from climate change and increasing demands for other sectors are important limiting factors, this presentation highlights the critical long-term impact on water quality. The Clean Smokestacks Act was enacted to reduce emissions from coal-fired power plants through installation of scrubbers and selective catalytic reduction, aiming to cut emissions of sulfur dioxide, nitrogen oxides and mercury. In addition to the capture of these air pollutants, volatile elements are attached to the residual coal combustion products (CCPs). Consequently, toxic metals concentrations in CCPs are extremely high and become mobile upon interaction of CCPs with aquatic solutions. In particular, several studies have demonstrated the high mobilization of boron, arsenic, selenium, barium and other toxic oxi-anions and metals from CCPs. The 2008 coal ash spill in Kingston, Tennessee, where approximately 4.1 million cubic meters of coal ash was spilled onto the surrounding land surface and into the adjacent Emory and Clinch Rivers, has demonstrated the possible impact of CCPs on the environment. An eighteen-month survey has revealed elevated levels of contaminants in surface water with restricted water exchange and in pore water extracted from the bottom sediments, downstream from the spill. Our research has shown that arsenic concentration in the pore water reached to 2,000 ppb due to the reducing conditions and the high mobility of the non-charged arsenic species. Generation of CCPs however is not restricted to a single accidental release, as over five hundred power plants nationwide generate approximately 130 million tons of CCPs each year, in which more than half is stored in 194 landfills and 161 holding ponds. In each of these sites effluents that are generated from leaching of CCPs could contain high levels of contaminants that could pose severe ecological hazards to the local aquatic systems. Preliminary results from Hyco Lake in North Carolina have demonstrated high levels of toxic metals in effluents that are generated from adjacent coal-fired plant combined with high boron concentrations (1000 ppb) in the fresh lake water. The notion that CCPs generates a direct threat to the aquatic systems through holding ponds, landfills, or even “beneficial use” in sites where CCPs could be exposed and interact with the ambient environment should become an additional factor in evaluating the cost of “cheap coal” and its impact on the environment.

  8. Investigation of the contents of natural radionuclides in coal and ashes from Kosovian power plants

    International Nuclear Information System (INIS)

    The basic aim of this work was investigation of the contents of natural radionuclides in the samples of coal and in the products of its burning in Kosovian power plants, as the beginning steps to estimate total radioactive effects on the surrounding, having in mind that coal power plants are one of the more influential source of the redistribution of natural radionuclides. The investigation has been done by gamma spectroscopy analysis using HP Ge detector, with relative efficiency of 20% and resolution of 1,8 keV in energy of 1332 keV 60Co. The activity concentration of natural radionuclides in measured samples of coal, ashes and slag were from 3,1 to 67 Bqkg-1 for 226Ra; from 1,7 to 32 Bqkg-1 for 232Th; from 0,3 to 6,5 Bqkg-1 for 235U; from 6,5 to 138 Bqkg-1 for 238U and from 14 to 234 Bqkg-1 for 40K. (author)

  9. 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

    A program of design, fabrication, and field testing of an on-line sulfur and ash analyzer was undertaken by The Babcock Wilcox Company. The analyzer is intended for use on coal slurry streams such as those found at coal cleaning facilities. The analyzer design consists of a sample preparation and delivery system (SPAD) and an inductively coupled plasma atomic emission spectrometer (ICP-AES). The program consisted of the following major tasks: Selection and screening of delivery systems; Design of the analyzer system; Fabrication of SPAD system; Field testing of the SPAD system; and Laboratory ICP testing of field collected samples. The field testing was conducted at CQ Inc., (Homer City, Pa. pilot plant). Testing was completed without taking the ICP to the field, since the analysis of coal slurry by ICP had been demonstrated during the delivery system screening tests and the field tests were aimed primarily at demonstrating the performance of the SPAD system. Although the ICP was not deployed to the field, the subsequent laboratory testing of field collected samples simulated the performance of the entire system. 16 refs., 103 figs., 38 tabs.

  10. Ash deposition during the co-firing of bituminous coal with pine sawdust and olive stones in a laboratory furnace

    Energy Technology Data Exchange (ETDEWEB)

    P. Abreu; C. Casaca; M. Costa [Technical University of Lisbon, Lisbon (Portugal). Mechanical Engineering Department

    2010-12-15

    This article describes an experimental study on ash deposition during the co-firing of bituminous coal with pine sawdust and olive stones in a laboratory furnace. The main objective of this study was to relate the ash deposit rates with the type of biomass burned and its thermal percentage in the blend. The thermal percentage of biomass in the blend was varied between 10% and 50% for both sawdust and olive stones. For comparison purposes, tests have also been performed using only coal or only biomass. During the tests, deposits were collected with the aid of an air-cooled deposition probe placed far from the flame region, where the mean gas temperature was around 640{sup o}C. A number of deposit samples were subsequently analyzed on a scanning electron microscope equipped with an energy dispersive X-ray detector. Results indicate that blending sawdust with coal decreases the deposition rate as compared with the firing of unblended coal due to both the sawdust low ash content and its low alkalis content. The co-firing of coal and sawdust yields deposits with high levels of silicon and aluminium which indicates the presence of ashes with high fusion temperature and, thus, with less capacity to adhere to the surfaces. In contrast, in the co-firing of coal with olive stones the deposition rate increases as compared with the firing of unblended coal and the deposits produced present high levels of potassium, which tend to increase their stickiness. 15 refs., 10 figs., 3 tabs.

  11. Chemical forms of the fluorine, chlorine, oxygen and carbon in coal fly ash and their correlations with mercury retention.

    Science.gov (United States)

    Deng, Shuang; Shu, Yun; Li, Songgeng; Tian, Gang; Huang, Jiayu; Zhang, Fan

    2016-01-15

    Fly ashes recovered from the particulate control devices at six pulverized coal boiler unites of China, are studied using an X-ray photoelectron spectroscopy (XPS) with a particular focus on the functionalities of fluorine (F), chlorine (Cl), carbon and oxygen on fly ash. It is found that the inorganic forms of F and Cl are predominant on the ash surface in comparison with their organics, and the proportion of organic Cl is relatively higher than that of organic F. Similar results are also obtained in the bulk by correlating the F and Cl contents with those of the unburnt carbon and other compositions in ash. Strong correlations of mercury retention with surface carbon-oxygen functional groups indicate that the C=O, OH/C-O and (O-C=O)-O on surface are of significant importance for mercury retention in fly ash. Their surface concentrations are related to coal type. The presence of Cl in fly ash helps with mercury retention. No obvious effect of F is observed. PMID:26410268

  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. Amelioration of coal fly ash used as cereal crops growth media by sphagnum peat moss and soil

    OpenAIRE

    Bilski J. et al.

    2012-01-01

    Coal fly ash (FA) has a potential to be used as a soil amendment for growing plants. Toxicity of heavy metals present in FY, FA high salinity, and high pH of coal FA may potentially restrict or even prevent plant growth on the media with high concentration of FA. Sphagnum peat moss (SPM) shows a potential to ameliorate coal FA based plant media by improving the texture of such media, making media less harder, decreasing high pH of the media, and potentially binding heavy metals present in FA....

  14. Raioactivity measurements of coal, fly ash, slag and soil samples in Afsin-Elbistan, Turkey

    International Nuclear Information System (INIS)

    Full text: A radiological characterization of coal, fly ash, slag and soil samples in Afshin-Elbistan in the Mediterranean region of Turkey was carried out. For this purpose, coal, fly ash, slag and 25 soil samples around the Afshin-Elbistan coal-fired power plant were collected from this region. The 1360 MW Afshin-Elbistan coal-fired thermal power plant is located near the small Turkish town Afshin, on the high plateau of Elbistan in the south east of Turkey. The plant was built in 1980 in the vicinity of a big coal mine and the spring wells of the river Ceyhan. Afsin-Elbistan is the biggest thermal power plant in Turkey with 4 340 MW ABB steam turbines. The collected samples were crushed thoroughly, dried at room temperature to constant weight and later crushed to pass through a 2 mm mesh sieve to homogenize them. Each sample was sealed for 30 days to reach radioactive equilibrium where the decay rate of the daughters becomes equal to that of the parent. The activities of Ra 226, Pb 214 and Bi 214 in equilibrium with their parents were assumed to represent the U 238 activity, while the activities of Ac 228 and Tl 208 were assumed to represent the Th 232 activity. Gamma spectrometry measurements were made with a coaxial high purity Ge detector of 15% relative efficiency and resolution 1.9 keV at the 1332 keV gamma of Co 60 (Canberra, GC 1519 model). The detector was shielded in a 10 cm thick lead well internally lined with 2 mm Cu foils. The detector output was connected to a spectroscopy amplifier (Canberra, Model 2025). The energy calibration and relative efficiency calibration of the spectrometer were carried out using calibration sources which contain Cd 109, Co 57, Ba 133, Na 22, Cs 137, Mn 54, and Co 60 peaks for energy range between 80 and 1400 keV. The counting time for each sample and background was 50.000 s. Gamma spectroscopy was used to determine the activities of U 238, Th 232, K 40 and Cs 137. The analysis shows that the samples include relevant natural radionuclides such as U 238, Th 232 and K 40 and the artificial radionuclide Cs 137. The mean specific activity concentrations of radionuclides Ra 226, Pb 214, Bi 214, Tl 208, Ac 228 and K 40 were 59.66, 33.39, 28.55, 14.77, 18.41 and 181.49 Bq/kg, respectively, for soil samples. The mean concentration of the artificial radionuclide Cs 137 is 3.79 Bq/kg and is not detected in some soil samples. Natural radionuclide concentrations Ra 226, Pb 214, Bi 214, Tl 208, Ac 228 and K 40 were found 109.68, 51.85, 38.54, 9.04, 10.21 and 56.67 Bq/kg for coal; 199.07, 191.09, 206.26, 13.94, 12.90 and 69.02 Bq/kg for slag; 198.43, 158.19, 166.07, 9.43, 11.59 and 86.70 Bq/kg for fly ash, respectively. A comparison of the concentrations obtained in this work with other parts of the world indicates that the radioactivity content of the samples is not significantly different

  15. Field trial of a pair production gauge for the on-line determination of ash in coal on a conveyor belt

    International Nuclear Information System (INIS)

    The ash content of coal can be determined by a method based on pair production. Coal is irradiated with high energy ?-rays and the resulting 0.511 MeV annihilation and Compton scattered ?-rays are measured. The pair production (PP) technique has been previously proved in the laboratory on static bulk samples and in the field on high-throughput sample by-lines. In the present paper, a plant test to assess the PP gauge for direct on-line conveyor belt analysis is described. This test was undertaken on the recirculating coal facility at the pilot plant coal washery at the BHP Steel Works, Newcastle, New South Wales. Seven Hunter Valley coals with ash in the range 7.5-33 wt% were circulated around the conveyor loop, and scanned by both PP and low energy ?-ray transmission (LET) gauges. Samples were measured on-belt as a function of sample depth, compaction, moisture and particle size. The mass per unit area of coal on the belt was varied in the range 40-210 kg m-2. The r.m.s. deviation between PP gauge ash and chemical laboratory ash was 1.07 wt% ash for 370 individual on-belt measurements on coal of mass per unit area greater than 60 kg m-2 ad 0.45 wt% ash for the mean ash of each sample. (author)

  16. Survey and conceptual flow sheets for coal conversion plant handling-preparation and ash/slag removal operations

    Energy Technology Data Exchange (ETDEWEB)

    Zapp, F.C.; Thomas, O.W.; Silverman, M.D.; Dyslin, D.A.; Holmes, J.M.

    1980-03-01

    This study was undertaken at the request of the Fossil Fuel Processing Division of the Department of Energy. The report includes a compilation of conceptual flow sheets, including major equipment lists, and the results of an availability survey of potential suppliers of equipment associated with the coal and ash/slag operations that will be required by future large coal conversion plant complexes. Conversion plant flow sheet operations and related equipment requirements were based on two representative bituminous coals - Pittsburgh and Kentucky No. 9 - and on nine coal conversion processes. It appears that almost all coal handling and preparation and ash/slag removal equipment covered by this survey, with the exception of some coal comminution equipment, either is on hand or can readily be fabricated to meet coal conversion plant capacity requirements of up to 50,000 short tons per day. Equipment capable of handling even larger capacities can be developed. This approach appears to be unjustified, however, because in many cases a reasonable or optimum number of trains of equipment must be considered when designing a conversion plant complex. The actual number of trains of equipment selected will be influenced by the total requied capacity of the complex, the minimum on-line capacity that can be tolerated in case of equipment failure, reliability of specific equipment types, and the number of reactors and related feed injection stations needed for the specific conversion process.

  17. Application and feasibility of coal fly ash and scrap tire fiber as wood wall insulation supplements in residential buildings

    International Nuclear Information System (INIS)

    Each year, nearly 55% of the fly ash (FA) produced by coal burning power plants in the United States is disposed of in landfills and ash ponds, while the amount of recycled fiber from scrap tires that is beneficially used in end-user markets is virtually negligible. This paper presents the results of a study carried out to investigate whether it might be possible to increase the thermal efficiency of a light-frame residential structure through addition of a fly ash-scrap tire fiber composite to traditional fiberglass insulation in light-frame wood residential construction. This type of construction represents more than 80% of the building stock in North America. The results of this study suggest that the fly ash-scrap tire fiber composite provides a sustainable supplement to traditional insulation that not only increases the efficiency of traditional insulation but can also help significantly reduce the environmental issues associated with disposal of these waste products. (author)

  18. 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 breakage in PBMN cells. Black-Right-Pointing-Pointer CFA-NPs resulted in mitochondrial membrane damage in PBMN cells.

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

    International Nuclear Information System (INIS)

    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 (μg/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-à-vis -Aq extract. Generation of superoxide anions (O2•−) 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: ► CFA consists of spherical crystalline nanoparticles in size range of 11–25 nm. ► Alkaline unwinding assay revealed single-strandedness in CFA treated ctDNA. ► CFA nanoparticles exhibited the ability to induce ROS and oxidative DNA damage. ► Comet and CBMN assays revealed DNA and chromosomal breakage in PBMN cells. ► CFA-NPs resulted in mitochondrial membrane damage in PBMN cells.

  20. Experimental study of the powder abrasion characteristics of materials used for coal ash pneumatic transport pipes

    Energy Technology Data Exchange (ETDEWEB)

    Mori, T.; Ono, H.; Nishiyama, Y.; Takase, T.

    1985-01-01

    In order to clarify the powder abrasion characteristics of the materials used for coal ash pneumatic transport pipes, sand blasting type apparatus was employed in a series of tests designed to provide a close simulation of the conditions encountered in actual pneumatic transport pipeline systems. Regarding the materials used in straight runs of pipe, it was found that the resistance of a low-carbon steel to powder abrasion was roughly the same as that of medium carbon steel. In other words, it is thought that material hardness has relatively little effect on wear resistance when the hardness of the abrasive powder is very much greater than that of the material. Regarding the materials used for curved sections of pipe, the powder abrasion observed on borided materials was very much less than that seen on high chromium cast iron. It was also confirmed that the effectiveness of boriding is dependent on the thickness of the boride layer. 11 references.

  1. Synthesis and characterization of zeolite from coal ashes modified by cationic surfactant

    International Nuclear Information System (INIS)

    Zeolite synthesized from coal fly ash was modified with different concentrations (2 and 20 mmol.L-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)

  2. Crystallization behavior at nucleation sites on the surfaces of vitreous materials loaded with coal bottom ash

    Energy Technology Data Exchange (ETDEWEB)

    Choi, C.; Kang, S. [Kyonggi University, Suwon (Republic of Korea). Dept. of Materials Engineering

    2009-03-15

    The degree of surface crystallization and the crystallization mechanism were investigated by using a non-isothermal and microstructural analysis for SiO{sub 2}-Al{sub 2}O{sub 3}-Li{sub 2}O glasses containing coal bottom ash whose surfaces were treated by using abrasives. For the main crystal phase, a beta-spodumene solid solution, the activation energy to grow and the Avrami constant were 263 kJ/mol and 1.97, respectively, based on a differential thermal analysis (DTA), so surface crystallization was preferred to bulk crystallization. The nucleation sites, which were generated on the surface by abrasive treatment, induced a surface crystallization. The hardness of the surface-treated specimens increased with increasing abrasive paper number owing to finer grains being created and to the enhanced degree of crystallization. Controlling the crystallization behavior of glass specimens is useful in fabricating glass-ceramics with various surface colors and enhanced physical properties.

  3. Impact of co-combustion of petroleum coke and coal on fly ash quality: Case study of a Western Kentucky power plant

    International Nuclear Information System (INIS)

    Petroleum coke has been used as a supplement or replacement for coal in pulverized-fuel combustion. At a 444-MW western Kentucky power station, the combustion of nearly 60% petroleum coke with moderate- to high-sulfur Illinois Basin coal produces fly ash with nearly 50% uncombusted petroleum coke and large amounts of V and Ni when compared to fly ash from strictly pulverized coal burns. Partitioning of the V and Ni, known from other studies to be concentrated in petroleum coke, was noted. However, the distribution of V and Ni does not directly correspond to the amount of uncombusted petroleum coke in the fly ash. Vanadium and Ni are preferentially associated with the finer, higher surface area fly ash fractions captured at lower flue gas temperatures. The presence of uncombusted petroleum coke in the fly ash doubles the amount of ash to be disposed, makes the fly ash unmarketable because of the high C content, and would lead to higher than typical (compared to other fly ashes in the region) concentrations of V and Ni in the fly ash even if the petroleum coke C could be beneficiated from the fly ash. Further studies of co-combustion ashes are necessary in order to understand their behavior in disposal

  4. Feasibility study on solidification of municipal solid waste incinerator fly ash with circulating fluidized bed combustion coal fly ash.

    Science.gov (United States)

    Liu, Wenshi; Hou, Haobo; Zhang, Chuhao; Zhang, Dajie

    2009-05-01

    The objective of this study was to assess the feasibility of solidification of municipal solid waste incinerator (MSWI) fly ash with circulation fluidized bed combustion (CFBC) fly ash, which is unsuitable as a cement replacement due to its high amounts of carbon, lime and anhydrite. The solidification process was conducted on samples prepared from MSWI fly ash, binders (cement clinkers and CFBC fly ash were mixed at two replacement ratios) and water (water/solid weight ratio = 0.4), among which the MSWI fly ash replaced each binder at the ratio of 0, 20, 40, 60 and 80% by dry weight. The samples were subjected to compressive strength tests and Toxicity Characteristic Leaching Procedure and the results showed that all solidified MSWI fly ash can meet the landfill standard imposed by US EPA after 28 days of curing. Micro-analysis (X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectrophotometry) revealed that the main hydrate products were C-S-H gel and ettringite, which have a positive effect on heavy metals retention. Therefore, this method provides a possibility to achieve a cheap and effective solution for MSWI fly ash management and use for CFBC fly ash. PMID:19423575

  5. Carbonation of brine impacted fractionated coal fly ash: implications for CO2 sequestration.

    Science.gov (United States)

    Nyambura, Muriithi Grace; Mugera, Gitari Wilson; Felicia, Petrik Leslie; Gathura, Ndungu Patrick

    2011-03-01

    Coal combustion by-products such as fly ash (FA), brine and CO(2) from coal fired power plants have the potential to impact negatively on the environment. FA and brine can contaminate the soil, surface and ground water through leaching of toxic elements present in their matrices while CO(2) has been identified as a green house gas that contributes significantly towards the global warming effect. Reaction of CO(2) with FA/brine slurry can potentially provide a viable route for CO(2) sequestration via formation of mineral carbonates. Fractionated FA has varying amounts of CaO which not only increases the brine pH but can also be converted into an environmentally benign calcite. Carbonation efficiency of fractionated and brine impacted FA was investigated in this study. Controlled carbonation reactions were carried out in a reactor set-up to evaluate the effect of fractionation on the carbonation efficiency of FA. Chemical and mineralogical characteristics of fresh and carbonated ash were evaluated using XRF, SEM, and XRD. Brine effluents were characterized using ICP-MS and IC. A factorial experimental approach was employed in testing the variables. The 20-150 μm size fraction was observed to have the highest CO(2) sequestration potential of 71.84 kg of CO(2) per ton of FA while the >150 μm particles had the lowest potential of 36.47 kg of CO(2) per ton of FA. Carbonation using brine resulted in higher degree of calcite formation compared to the ultra-pure water carbonated residues. PMID:20970918

  6. Evaluation of Some Parameters in Relation to Hydraulic Stowing of Pond Ash in Underground Coal Mines: A Prototype Study

    Science.gov (United States)

    Mishra, D. P.; Das, S. K.

    2015-04-01

    Various parameters in relation to hydraulic stowing of pond ash such as rate of water drainage from the pond ash, water absorption by the pond ash, percentage of stowing and percentage of void were evaluated using a mine goaf model stowed with pond ash slurries of five concentrations varying from 45 to 65 % at 5 % increment to identify the suitable slurry concentration for effective stowing in underground coal mines. The study revealed that the rate of water drainage from the stowed pond ash is highest during the initial 15 min of stowing and it gradually decreases with time. Also, it was observed that the percentages of water absorption by the pond ash and stowing increase with the increment of slurry concentration. It was concluded that pond ash slurries of higher concentrations such as 60 and 65 %, which yield better results in terms of higher stowing percentage in the 1st phase of stowing itself and higher water absorption, may be considered appropriate for stowing.

  7. Coal Ash Aerosol in East Asian Outflow as a Source for Oceanic Deposition of Iron and Other Metals

    Science.gov (United States)

    Anderson, J. R.; Hua, X.

    2008-12-01

    While ocean deposition of East Asian dust is given significant emphasis as a source of biologically-active trace elements, iron in particular, dust events are episodic and highly seasonal. There is, however, a constant source of aerosol that is chemically similar to dust (albeit amorphous in structure rather than crystalline) in the ash particles emitted from many hundreds of coal-fired power plants that are sited along the entire coastal region of China and Korea. The emission controls on these facilities vary widely and, in even cases of state-of-the-art emission controls, the secondary release of ash can be significant. There are of course even more small industrial and household sources of coal combustion emissions, in most cases with little or no emissions controls. Ash from a modern coal-fired power facility in Korea has been examined chemically and morphologically with electron microscopic techniques. As is characteristic of all such facilities, two principal types of ash are present: (1) flyash, silicate glass spheres that are emitted with the smoke and removed by electrostatic precipitators; and (2) bottom ash, "clinkers" and noncombustible material sticking to the furnace walls that are mixed with water and ground after cooling, then removed as a slurry to a dumping area. In addition, iron sulfide (pyrite) is a common constituent of coal and provides both a source of sulfur dioxide gas and also molten iron spherical particles in the ash. The iron spheres then are rapidly oxidized upon cooling. Bottom ash is a more complex material than flyash in that it contains more iron and other trace metals, plus it contains varying amounts of uncombusted carbon. The post-combustion handling of bottom ash can lead to significant emissions despite the fact that little or none goes out the stack. The iron oxide spheres can also be emitted by this secondary method. The concentrations of ash can be very high in close proximity to power plants (PM10 of several hundred micrograms per cubic meter of air) and traces of these aerosols have been found in the ACE-Asia and PACDEX experiments above the Sea of Japan, the Yellow Sea and across the width of the North Pacific.

  8. Adsorptive removal of various phenols from water by South African coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Potgieter, J.H.; Bada, S.O.; Potgieter-Vermaak, S.S. [Manchester Metropolitan University, Manchester (United Kingdom)

    2009-01-15

    South African coal fly ash (SACFA) was used to effectively remove phenol, 2-nitrophenol and 4-nitrophenol from wastewater. The rate of adsorption follows first-order kinetics before attaining equilibrium with the sorption rate (K{sub ad}) obtained being the highest for 4-nitrophenol (p-nitrophenol) (7.0 x 10{sup -3}/h), followed by phenol (1.2 x 10{sup -3}/h) and 2-nitrophenol (o-nitrophenol) (1.0 x 10{sup -3}/h). Batch studies were performed to evaluate the adsorption process, and it was found that the Freundlich isotherm effectively fits the experimental data for the adsorbates better than the Langmuir model, with the fly ash having the highest adsorption capacity of 6.51 x 10{sup -2} mg/g for 4-nitrophenol, 6.00 x 10{sup -2} mg/g for 2-nitrophenol and 6.31 x 10{sup -2} mg/g for phenol. The fly ash was found to adsorb 90.2% of phenol, 88.9% of 2-nitrophenol and 92.6% of 4-nitrophenol at an initial concentration of 20 mg/l. The desorption studies suggested that the desorption of 4-nitrophenol was the most difficult of the three adsorbates to be desorbed. The desorption efficiency was 17.9% for phenol, 18.8% for 2-nitrophenol and 10.2% for 4-nitrophenol. This work proved that SACFA can be used as an efficient adsorbent material for removal of phenol from water and wastewater.

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

    Energy Technology Data Exchange (ETDEWEB)

    Lu, S.G., E-mail: lusg@zju.edu.cn [College of Environmental and Resource Sciences, Zhejiang University, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Hangzhou 310029 (China); Chen, Y.Y. [Institute of Applied Biological Resources, Zhejiang University, Hangzhou 310029 (China); Shan, H.D.; Bai, S.Q. [College of Environmental and Resource Sciences, Zhejiang University, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Hangzhou 310029 (China)

    2009-09-30

    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 (<0.1 mg/L). The GJST-extractable Cd, Cr, Cu, and Pb concentrations in the MFs are higher those in the NMFs. No significant difference in the leachability ratio of Cr, Cu and Pb with TCLP and GJST is found in the MFs and NMFs. However, the GJST test showed that Pb has higher leachability in MFs than that in NMFs. The leachability ratio of heavy metals has an order of Cu > Cr > Pb > Cd. The heavy metals of fly ashes have a great potential to be released into the environment under acid environment.

  10. Chemical composition of glass and crystalline phases in coarse coal gasification ash

    Energy Technology Data Exchange (ETDEWEB)

    R.H. Matjie; Zhongsheng Li; Colin R. Ward; David French [Sasol Technology (Pty) Ltd., Sasolburg (South Africa)

    2008-05-15

    A procedure has been developed for determining the chemical composition and relative abundance of the amorphous or glassy material, as well as crystalline phases, present in coarse coal gasification ash, in order to assist in predicting the behaviour of the material in cement/brick/concrete applications. The procedure is based on a combination of quantitative X-ray diffraction (XRD), chemical analysis and electron microprobe studies. XRD analysis indicates that the clinker samples contain a number of crystalline high temperature phases, including anorthite, mullite, cristobalite, quartz and diopside. Quantitative evaluation using Rietveld-based techniques has been used to determine the percentages of both the individual crystalline phases and the glass component. These data were then combined with the chemistry of the crystalline phases and the overall chemical composition of the ash to estimate the chemical composition of the glass phase, which is typically the most abundant component present in the different materials. Although there is some degree of scatter, comparison between the inferred glass composition from XRD and bulk chemistry and actual data on the glass composition using electron microprobe techniques suggest that the two approaches are broadly consistent. The microprobe further indicates that a range of compositions are present in the glassy and crystalline components of the ashes, including Si-Al-rich glass, metakaolin and Fe-Ca-Mg-Ti phases, as well as quartz, anorthite and an aluminophosphate material. Electron microprobe and XRD studies also show that pyrrhotite (FeS), representing a high temperature transformation product of pyrite, is present in some clinker and partially burnt carbonaceous shale samples. 27 refs., 5 figs., 7 tabs.

  11. 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

  12. Strength properties of concrete incorporating coal bottom ash and granulated blast furnace slag

    Energy Technology Data Exchange (ETDEWEB)

    Ozkan, O.; Yuksel, I.; Muratoglu, O. [Zonguldak Karaelmas University, Zonguldak (Turkey)

    2007-07-01

    Coal bottom ash (CBA) and fly ash (FA) are by-products of thermal power plants. Granulated blast-furnace slag (GBFS) is developed during iron production in iron and steel plants. This research was conducted to evaluate the compressive strength property and some durability characteristics of concrete incorporating FA, CBA, and GBFS. FA is used as an effective partial cement replacement; CBA and GBFS are used as partial replacement for fine aggregate without grinding. Water absorption capacity, unit weight and compressive strengths in 7, 28, and 90-day ages were assessed experimentally. For these experiments, concrete specimens were produced in the laboratory in appropriate shapes. The samples are divided into two main categories: M1, which incorporated CBA and GBFS; and M2, which incorporated FA, CBA, and GBFS. Remarkable decreases are observed in compressive strength and water absorption capacity of the concrete; bulk density of the concrete is also decreased. It can be concluded that if the content of CBA and GBFS is limited to a reasonable amount, the small decreases in strength can be accepted for low strength concrete works.

  13. 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

  14. 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.

  15. Utilization of coal-biomass fly ash in reactive barriers for treating acid mine drainage

    International Nuclear Information System (INIS)

    Coal- and biomass-derived fly ash (CBFA) was used as a reactive barrier system for treating acid mine drainage. Two reactive barriers were investigated, notably a flow-through reactive barrier with minimum disruption to the existing flow regime, and a low-permeability barrier for the construction of containment dams. A synthetic acid mine drainage system was prepared in a laboratory. Kinetic column tests were conducted to analyze the effects of acid mine drainage flow on the hydraulic conductivity and leachate composition for mixtures of mine tailings and CBFA. The tests demonstrated that a mixture of the CBFA of between 10 to 50 per cent with mine tailings increased the pH and decreased the dissolved concentrations of heavy metals in acid mine drainage. Mineral precipitation caused large reductions in hydraulic conductivity in relation to the cumulative amounts of acid mine drainage flowing through the columns. It was concluded that the number of progressive pore volumes of acid mine drainage required for achieving reductions in hydraulic conductivity is inversely related to the fly ash content of the column packs. 13 refs., 4 tabs., 7 figs.

  16. 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.

  17. Determination of uranium concentrations and its activity ratios in coal and fly ash from Philippine coal-fired thermal power plants using ICP-MS and TIMS

    International Nuclear Information System (INIS)

    The specific activity of 238U as a technologically enhanced naturally occurring radioactive material (TENORM) in feed coal, bottom and fly ash samples from four major coal-fired thermal power plants in the Philippines have been measured using high-resolution gamma-ray spectroscopy system equipped with a high-purity germanium (HPGe) detector. The uranium concentration has been determined from same samples using inductively coupled plasma mass spectrometry (ICP-MS). There was a good correlation between the measured uranium using both methods and has been estimated to be 0.98. Uranium from coal, bottom and fly ash samples were chemically separated and activity ratio (234U/238U) and 235U/238U ratio was measured using a thermal ionization mass spectrometer (TIMS). The highest concentration of uranium was found in fly ash and lowest was for feed coal. Uranium isotopic composition plays an important role in studying its biogeochemical behavior and is a good tracer on the sources of uranium in the environment. (orig.)

  18. Properties of high ash coal-char particles derived from inertinite-rich coal: II. Gasification kinetics with carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Raymond C. Everson; Hein W.J.P. Neomagus; Rufaro Kaitano; Rosemary Falcon; Vivien M. du Cann [North-West University, Potchefstroom (South Africa). Separation Science and Technology Research Group

    2008-11-15

    The reaction rate of carbon dioxide-nitrogen gas mixtures with a well-characterised high ash char derived from an inertinite-rich coal discard was investigated by experimentation and reaction rate modelling. Experimentation with a thermogravimetric analyzer at 87.5 kPa and 287.5 kPa between 850{sup o}C and 900{sup o}C and with 1mm diameter particles, similar to operating conditions used for bubbling fluidised bed gasification, was carried out. The char consisted of a large proportion of dense char formed from the inertinite in the parent coal, fine pores from the low concentration of reactive macerals and cracks formed as a result of thermal deflagration. The effects of carbon dioxide concentration, temperature and pressure on the carbon conversion with time were found to follow expected trends with long reaction times. The random pore model, which accounts for intraparticle structural changes, was examined to predict the overall reaction rate. For this evaluation, a new procedure was developed to determine the structural parameter which could not be calculated directly from initial characterisation results. This procedure consists of defining a reduced time parameter, which conveniently eliminates the effect of the intrinsic kinetics when conversion versus the reduced time results is used. Thus, the structural parameter, which characterises the pore growth and coalescence, can be evaluated by a regression procedure using experimental results obtained at all temperatures and pressures. Intrinsic reaction parameters based on the power rate law were also calculated from carbon conversion versus real time results using a stepwise regression procedure. It was found that the random pore model predictions for the carbon conversion with time using the determined parameters correlated very well with experimental results, thus confirming that the reaction rate is chemical-reaction controlled. 29 refs., 9 figs., 4 tabs.

  19. Influence of coal ash and slag dumping on dump waste waters of the Kostolac power plants (Serbia)

    Energy Technology Data Exchange (ETDEWEB)

    Popovic, A.; Djinovic, J. [University of Belgrade, Belgrade (Serbia)

    2006-10-01

    The content of selected trace and major elements in the river water used for transport, as well as in the subcategories of the waste waters (overflow and drainage) were analyzed in order to establish the influence of transport and dumping of coal ash and slag from the 'Kostolac A' and 'Kostolac B' power plants located 100 km from Belgrade (Serbia). It was found that during transport of coal ash and slag to the dump, the water used for transport becomes enriched with manganese, nickel, zinc, chromium, vanadium, titanium, cobalt, arsenic, aluminum, and silicon, while more calcium, iron, cadmium, and lead are adsorbed by the ash and slag than is released from them. There is also an equilibrium between the release and adsorption processes of copper and magnesium during transport. The vertical penetration of the water used for transport results in a release of calcium, magnesium, manganese, and cadmium to the environment, while iron, nickel, zinc, chromium, copper, lead, vanadium, titanium, cobalt, and arsenic are adsorbed by the fractions of coal ash and slag in the dump.

  20. 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, 5.7cm, with stable heat flux values of 230, 200, 175, and 125kW/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

  1. 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 2098% and 5098% 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 45120 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%

  2. Studies on SG (self-hardening slurry) method. Part 12. Development of SG-using coal ash; SG (jikosei anteieki) koho ni kansuru kenkyu. 12. Sekkaibai wo riyoshita SG no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Kubo, H.; Kawachi, T.; Sukawa, K.; Yamada, S. [Obayashi Corp., Tokyo (Japan)

    1995-08-10

    Self-hardening Slurry (SG), one of the flurries used in the diaphragm wall method, is currently prepared by the mixing of water, bentonite, cement and additives. Meanwhile, coal ash from thermal power plants and other facilities has increased year by year, resulting in an increase in the volume of coal ash dumped. Therefore, the expansion of coal ash use is required. For the purpose of coal ash reuse, and the improvement and cost reduction of SG, SG containing large quantities of coal ash was researched. Coal ash-SG, containing 600 kg to 850 kg of ash per cubic meter of SG, achieved a reduction in the quantity of bentonite and cement used, and a heightened stability in trench excavation because of its increased density. In addition, a convenient and fast test was established for the mix-proportion design corresponding to varieties of coal ash. On the basis of these results, coal ash-SG was applied to 19,000 m{sup 2} of water cutoff wall in the construction of the coal ash dumping site. The workability and quality of coal ash-SG were found to be satisfactory. 16 refs., 19 figs., 2 tabs.

  3. 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.

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

    International Nuclear Information System (INIS)

    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: ► We model Bulgarian power plants which have regulated minerals nanoparticles can contain hazardous elements. ► We study changes in the level of information about nanominerals importance and the effect on human health exposure. ► Increasing information will increase quality if power plants procedures are similar.

  5. Effective utilization of waste ash from MSW and coal co-combustion power plant-Zeolite synthesis

    International Nuclear Information System (INIS)

    The solid by-product from power plant fueled with municipal solid waste and coal was used as a raw material to synthesize zeolite by fusion-hydrothermal process in order to effectively use this type of waste material. The effects of treatment conditions, including NaOH/ash ratio, operating temperature and hydrothermal reaction time, were investigated, and the product was applied to simulated wastewater treatment. The optimal conditions for zeolite X synthesis were: NaOH/ash ratio = 1.2:1, fusion temperature = 550 deg. C, crystallization time = 6-10 h and crystallization temperature = 90 deg. C. In the synthesis process, it was found that zeolite X tended to transform into zeolite HS when NaOH/ash ratio was 1.8 or higher, crystallization time was 14-18 h, operating temperature was 130 deg. C or higher. The CEC value, BET surface area and pore volume for the synthesized product at optimal conditions were 250 cmol kg-1, 249 m2 g-1 and 0.46 cm3 g-1 respectively, higher than coal fly ash based zeolite. Furthermore, when applied to Zn2+ contaminated wastewater treatment, the synthesized product presented larger adsorption capacity and bond energy than coal fly ash based zeolite, and the adsorption isotherm data could be well described by Langmuir and Freundlich isotherm models. These results demonstrated that the special type of co-combustion ash from power plant is suitable for synthesizing high quality zeolite, and the products are suitable for heavy metal removal from wastewater

  6. Coal fly ash basins as an attractive nuisance to birds: Parental provisioning exposes nestlings to harmful trace elements

    International Nuclear Information System (INIS)

    Birds attracted to nest around coal ash settling basins may expose their young to contaminants by provisioning them with contaminated food. Diet and tissues of Common Grackle (Quiscalus quiscala) nestlings were analyzed for trace elements to determine if nestlings were accumulating elements via dietary exposure and if feather growth limits elemental accumulation in other tissues. Arsenic, cadmium, and selenium concentrations in ash basin diets were 5× higher than reference diets. Arsenic, cadmium, and selenium concentrations were elevated in feather, liver, and carcass, but only liver Se concentrations approached levels of concern. Approximately 15% of the total body burden of Se, As, and Cd was sequestered in feathers of older (>5 days) nestlings, whereas only 1% of the total body burden of Sr was sequestered in feathers. Feather concentrations of only three elements (As, Se, and Sr) were correlated with liver concentrations, indicating their value as non-lethal indicators of exposure. - Highlights: ► We examined elemental uptake by grackle nestlings associated with coal ash basins. ► Diet of ash basin nestlings had higher levels of Se, As, and Cd than control nestlings. ► Se, As, Cd, and Sr concentrations of ash basin nestling tissues were elevated. ► Only Se in nestling liver approached published levels of concern. ► Nestling feathers sequestered >15% of the total body burden of Se, As, and Cd. - Nestlings of common grackles attracted to nest around coal ash settling basins were exposed to elevated dietary Se, As, Cd, and Sr, resulting in elevated Se tissue concentrations approaching reported levels of concern.

  7. Use of zeolitised coal fly ash for landfill leachate treatment: A pilot plant study

    Energy Technology Data Exchange (ETDEWEB)

    Luna, Y.; Otal, E.; Vilches, L.F.; Vale, J.; Querol, X.; Pereira, C.F. [University of Seville, Seville (Spain)

    2007-07-01

    Treatment of municipal solid waste (MSW) landfill leachate generally results in low percentages of nutrient removal due to the high concentration and accumulation of refractory compounds. For this reason, individual physical, chemical and biological processes have been used for the treatment of raw landfill leachate and sometimes for the mixture of domestic wastewater and landfill leachate. In this work, the possibility of treating landfill leachate was tested in a bench-scale pilot plant by a two-step method combining adsorption and coagulation-flocculation. Zeolite synthesized from coal fly ash, a by-product of coal-fired power stations, was used in this study both as a decantation aid reagent and as an adsorbent of COD and NH{sub 4}-N. The coagulation-flocculation step was performed by the use of aluminium sulphate and a polyelectrolyte (ACTIPOL A-401). The leachate was collected directly from a storage unit of the organic fraction of MSW, before it was composted. For this reason the raw leachate was diluted before treatment. The sludge was recirculated to enhance the removal efficiency of nutrients as well as to optimize flocculant saving and to decrease sludge production. The results showed that it is possible to remove 43%, 53% and 82% of COD, NH{sub 4}-N, and suspended solids, respectively. Therefore, this method may be an alternative for ammonium removal, as well as a suitable pre- or post-treatment step, in combination with other processes in order to meet regulatory limits.

  8. Reproduction and hatchling performance in freshwater turtles associated with a remediated coal fly-ash spill.

    Science.gov (United States)

    Steen, David A; Van Dyke, James U; Jackson, Brian P; Hopkins, William A

    2015-04-01

    In 2008 an impoundment retaining wall failed at the Tennessee Valley Authority's coal burning plant in Kingston, Tennessee, releasing large quantities of coal-fly ash into the Emory River. Following extensive remediation of the spill, we captured (in 2011 and 2012) gravid turtles of multiple species in three rivers (two impacted and one reference) within the vicinity of the spill to determine whether there was evidence of the spill influencing reproduction. There was little evidence that river of origin affected reproductive output, hatching success, hatchling size, or hatchling locomotor performance. Although hatching success and hatchling righting ability of pond sliders, Trachemys scripta, was higher in our reference river than in the Emory or Clinch River, respectively, these differences could not be attributed to differences in individual element concentrations in turtle tissues and effect sizes were relatively small. For example, hatching success was reduced by 11% in the spill zone compared to the reference river, an effect that is unlikely substantial enough to influence local population dynamics in light of turtle life history. Our results suggest that residual contamination that remains in the Emory-Clinch system after its remediation poses low risk of excessive element exposure and limited adverse reproductive effects to freshwater turtles. Future monitoring could reveal whether the observed reduction in hatching success gradually attenuates with time, or whether any long-term effects of chronic exposure to low-level contamination emerge over time. PMID:25682257

  9. 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

  10. Removal of Copper(II) and Zinc(II) Ions From Aqueous Solution by Chemical Treatment of Coal Fly Ash

    OpenAIRE

    So?o, Eleonora; Kalembkiewicz, Jan

    2015-01-01

    The aim of this study was to investigate the chemical modifications of coal fly ash (CFA) treated with HNO3 or ammonium acetate (AcNH4) or NaOH or sodium diethyldithiocarbamate (NaDDTC) as an adsorbent for the removal of copper(II) and zinc(II) ions from aqueous solution. The morphology of fly ash grains before and after modification was examined via X-ray diffraction (XRD) and images of scanning electron microscope (SEM). Adsorption of copper(II) and zinc(II) ions was conducted under batch p...

  11. Liquid phase sintering of dense and porous glass-ceramics from coal fly-ash and waste glass

    OpenAIRE

    Bossert J.; Fidancevska E.; Mangutova B.; Panova B.; Milosevski D.; Milosevski M.

    2004-01-01

    Glass-ceramics were produced utilizing fly-ash from coal power stations and waste glass of TV monitors, windows and flask glass. The powder technology route was employed. The mixture of 50% fly ash and 50% waste TV glass increases the bending strength from 12±1 to 56±4 MPa and E-modulus from 6±1 to 26±3 GPa. Using polyurethane foam and C-fibers as pore creators porosity of 70±4 and 55±5 %, respectively, can be obtained-modulus and bending strength of the porous systems obtained by polyurethan...

  12. Catalytic effects of coal ash and externally loaded Na on NH{sub 3} formation during the gasification of a Victorian brown coal in steam

    Energy Technology Data Exchange (ETDEWEB)

    F.-J. Tian; L. Chang; J.-I. Hayashi; T. Chiba; C.-Z. Li [Monash University, Vic. (Australia). Department of Chemical Engineering

    2003-07-01

    The development of gasification-based power generation technologies using coal will lead to great reductions in the emission of CO{sub 2} due to the high efficiencies compared with the current pulverised-fuel combustion technologies. However, the gasification-based technologies will also have to meet the increasingly stringent environmental standards on the emission of other pollutants such as NOx. Understanding the conversion mechanism of fuel nitrogen to NOx and NOx precursors (mainly NH{sub 3} and HCN) during gasification is essential for the optimum strategies of NOx abatement from the future power plants. However, the formation of NH{sub 3} and HCN during coal gasification in steam is still poorly understood. In this study, a novel fluidised-bed/fixed-bed reactor has been used to investigate the effects of coal ash and externally loaded Na on NH{sub 3} formation during the gasification of a Victorian brown coal in steam at 700{degree}C and 800{degree}C. Coal ash greatly enhanced the formation of NH{sub 3} from char-N. Experiments with Na{sub 2}CO{sub 3}-loaded and NaCl-loaded coal samples indicated that Na in the ash was at least partially responsible for the catalysed formation of NH{sub 3}. The catalysed formation of NH{sub 3} was likely to be at the expense of the formation of HCN and other N-containing species (NOx, N{sub 2}O, HCNO, N{sub 2}). Based on the experimental data, the reaction mechanisms for the formation of NH{sub 3} and HCN are discussed. 25 refs., 4 figs., 1 tab.

  13. Equipment for the measurement of natural-gamma radiation for the analysis of ash content and the content of particular chemical elements in coal

    International Nuclear Information System (INIS)

    An experimental system for measuring the ash content of washed coal has been installed at a coal washing plant in Spain. The equipment, which includes a scintillation detector, carries out a radiometric analysis of the coal by measuring the natural gamma radiation. Good agreement has been obtained with the results of combustion analysis of the same coal samples. It has also been demonstrated that the equipment can be used to determine the concentrations of particular minerals. (UK)

  14. 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,