WorldWideScience

Sample records for alkaline coal ash

  1. Nitrogen mineralization from sludge in an alkaline, saline coal gasification ash environment.

    Science.gov (United States)

    Mbakwe, Ikenna; De Jager, Pieter C; Annandale, John G; Matema, Taurai

    2013-01-01

    Rehabilitating coal gasification ash dumps by amendment with waste-activated sludge has been shown to improve the physical and chemical properties of ash and to facilitate the establishment of vegetation. However, mineralization of organic N from sludge in such an alkaline and saline medium and the effect that ash weathering has on the process are poorly understood and need to be ascertained to make decisions regarding the suitability of this rehabilitation option. This study investigated the rate and pattern of N mineralization from sludge in a coal gasification ash medium to determine the prevalent inorganic N form in the system and assess the effect of ash weathering on N mineralization. An incubation experiment was performed in which fresh ash, weathered ash, and soil were amended with the equivalent of 90 Mg ha sludge, and N mineralization was evaluated over 63 d. More N (24%) was mineralized in fresh ash than in weathered ash and soil, both of which mineralized 15% of the initial organic N in sludge. More nitrification occurred in soil, and most of the N mineralized in ash was in the form of ammonium, indicating an inhibition of nitrifying organisms in the ash medium and suggesting that, at least initially, plants used for rehabilitation of coal gasification ash dumps will take up N mostly as ammonium. PMID:23673951

  2. 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 oer 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.

  3. 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

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

    Science.gov (United States)

    Kim, Kangjoo; Park, Sung-Min; Kim, Jinsam; Kim, Seok-Hwi; Kim, Yeongkyoo; Moon, Jeong-Tae; Hwang, Gab-Soo; Cha, Wang-Seog

    2009-09-01

    The geochemical behavior of As in porewaters of an alkaline coal ash disposal site was investigated using multilevel samplers. The disposal site was in operation from 1983 until 1994 and was covered with 0.3-0.5m thick soils in 2001 when this study was initiated. Sequential extraction analyses and batch leaching experiments were also performed using the coal ash samples collected from the disposal site. The results suggest the important roles of siderite (FeCO(3)) precipitation/dissolution and soil cover, which have been ignored previously. Arsenic levels in the porewater were very low (average of 10microgL(-1)) when the site was covered with soil due to coprecipitation with siderite. The soil cover enabled the creation of anoxic conditions, which raised the Fe concentration by the reductive dissolution of Fe-(hydr)oxides. Because of the high alkalinity generated from the alkaline coal ash, even a small increase in the Fe concentration (0.66mgL(-1) on average) could cause siderite precipitation. When the soil cover was removed, however, an oxidizing condition was created and triggered the precipitation of dissolved Fe as (hydr)oxides. As a result, the dissolution of previously precipitated As-rich siderite caused higher As concentration in the porewater (average of 345microgL(-1)). PMID:19682722

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-09-15

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

  6. 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.

  7. 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 ?g 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

  8. Fusibility of coal ash

    Energy Technology Data Exchange (ETDEWEB)

    Unuma, H.; Takeda, S.; Sayama, S.; Itoh, S.

    1985-01-01

    The physical and chemical changes occurring in coal ash in the vicinity of its melting point have been inferred from the results of differential thermal analysis of ashes derived from 24 different coals (both Japanese and non-Japanese) and various ash model compounds. The authors also propose an equation for obtaining an index which enables ash melting points to be correlated with mineral fractions. The correlation coefficient here is 0.85, which is a better result than that obtained in the conventional correlation of melting point with basicity. As an additional assessment of the soundness of this new index, previously quoted melting points are plotted alongside the results obtained by the authors. 4 references, 5 figures.

  9. Ash Microspheres for Coal Burning

    International Science & Technology Center (ISTC)

    Estimation of perspectives for ash microspheres production at coal burning thermal power stations , development of methods for their quality certification. Creation of a database for ash microspheres in Russian Federation.

  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. 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

  12. COAL ASH RESOURCES RESEARCH CONSORTIUM

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-12-01

    The Coal Ash Resources Research Consortium (CARRC, pronounced ?cars?) is the core coal combustion by-product (CCB) research group at the Energy & Environmental Research Center (EERC). CARRC focuses on performing fundamental and applied scientific and engineering research emphasizing the environmentally safe, economical use of CCBs. CARRC member organizations, which include utilities and marketers, are key to developing industry-driven research in the area of CCB utilization and ensuring its successful application. CARRC continued the partnership of industry partners, university researchers, and the U.S. Department of Energy (DOE) addressing needs in the CCB industry through technical research and development projects. Technology transfer also continued through distribution and presentation of the results of research activities to appropriate audiences, with emphasis on reaching government agency representatives and end users of CCBs. CARRC partners have evolved technically and have jointly developed an understanding of the layers of social, regulatory, legal, and competition issues that impact the success of CCB utilization as applies to the CCB industry in general and to individual companies. Many CARRC tasks are designed to provide information on CCB performance including environmental performance, engineering performance, favorable economics, and improved life cycle of products and projects. CARRC activities from 1993?1998 included a variety of research tasks, with primary work performed in laboratory tasks developed to answer specific questions or evaluate important fundamental properties of CCBs. The tasks summarized in this report are 1) The Demonstration of CCB Use in Small Construction Projects, 2) Application of CCSEM (computer-controlled scanning electron microscopy) for Coal Combustion By-Product Characterization, 3) Development of a Procedure to Determine Heat of Hydration for Coal Combustion By-Products, 4) Investigation of the Behavior of High-Calcium Coal Combustion By-Products, 5) Development of an Environmentally Appropriate Leaching Procedure for Coal Combustion By-Products, 6) Set Time of Fly Ash Concrete, 7) Coal Ash Properties Database (CAPD), 8) Development of a Method for Determination of Radon Hazard in CCBs, 9) Development of Standards and Specifications, 10) Assessment of Fly Ash Variability, and 11) Development of a CCB Utilization Workshop. The primary goal of CARRC is to work with industry to solve CCB-related problems and promote the environmentally safe, technically sound, and economical utilization and disposal of these highly complex materials. CARRC 1993?1998 accomplishments included: C Updating the CAPD to a user-friendly database management system, and distributing it to CARRC members. C ASTM standard preparation for a guide to using CCBs as waste stabilization agents. C Preliminary identification of specific mineral transformations resulting from fly ash hydration. C Limited determination of the effects of fly ash on the set time of concrete. C Statistical evaluation of a select set of fly ashes from several regional coal-fired power plants. C Development and presentation of a workshop on CCB utilization focused on government agency representatives and interested parties with limited CCB utilization experience. C Participation in a variety of local, national, and international technical meetings, symposia, and conferences by presenting and publishing CCB-related papers.

  13. Studies of the fusibility of coal ash

    Energy Technology Data Exchange (ETDEWEB)

    Unuma, H.; Takeda, S.; Tsurue, T.; Ito, S.; Sayama, S.

    1986-11-01

    To establish a means for predicting the melting temperature of coal ash, the chemical composition, mineral matter content and melting temperature were investigated for 24 coal ash samples. The fusibility of coal ash was studied from the view point of the mineral matter. The melting temperatures of these samples ranged from 1285 to > 1500/sup 0/C. A conventional acid-base index did not show a good correlation with melting temperature for these coal ash samples (correlation coefficient -0.67) and the reason for this is discussed. An empirical index, which is derived from the correlation between mineral composition and melting temperature, is proposed. It was linearly proportional to melting temperature for the coal ash samples (correlation coefficient 0.85) and furthermore, the applicability of the index to arbitrary coal ash was demonstrated. 7 refs., 5 figs., 1 tab.

  14. Removal of boron from coal fly ash by washing with HCl solution

    Energy Technology Data Exchange (ETDEWEB)

    Shunsuke Kashiwakura; Hironari Kubo; Yuichi Kumagai; Hiroshi Kubo; Kazuyo Matsubae-Yokoyama; Kenichi Nakajima; Tetsuya Nagasaka [Tohoku University, Sendai (Japan). Graduate School of Environmental Studies

    2009-07-15

    Boron as an environmentally regulated substance is well known to condense in the coal fly ash generated from coal combustion plants. Since boron in the coal fly ash tends to elute into the soil easily, a technology for its stabilization or removal from fly ash is required. An acid washing process is proposed and studied as one of the candidate technologies for the removal of boron from coal fly ash. A laboratory-scale investigation is conducted on the dissolution behavior of boron in the coal fly ash in a diluted HCl solution. The dissolution of boron and alkaline species is considerably fast and exhibits a behavior different from that of aluminum and silicon, which are major components of the ash. From the kinetic model, it is expected that boron in the ash may mainly be in the form of alkaline or alkaline earth borates that are deposited on the surface of relatively large ash particles of alumino-silicate or may be precipitated as fine particles during coal combustion. This acid washing process is extended to a bench-scale plant and boron is successfully removed from the coal fly ash until its content is less than the regulation limit. 14 refs., 8 figs., 1 tab.

  15. Physical properties of coal ash during heating

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, S.; Unuma, H.; Tsurue, T.; Sayama, S.; Itoh, S.

    1985-01-01

    A study is reported of the fundamental properties of the ashes obtained from 24 different coals (from Japan and other countries) by low-temperature ashing and ashing at 800 C. An initial mineral composition common to all the low-temperature ashes was discovered from the results of X-ray diffraction and chemical analysis. In addition, TG-DTA and X-ray diffraction data revealed the changes that occurred in the mineral content of coal during heating. The authors also report measurements of softening, melting and flow points. 1 reference, 6 figures, 2 tables.

  16. Elemental analysis of coal and coal ASH by PIXE technique

    Energy Technology Data Exchange (ETDEWEB)

    Patra, K.C. [Dept. of Physics, Sambalpur University, Jyoti Vihar, Burla (India); Institute of Physics, Sachivalaya Marg, Bhubaneswar - 751005 (India); Rautray, Tapash R., E-mail: tapash.rautray@gmail.com [Institute of Physics, Sachivalaya Marg, Bhubaneswar - 751005 (India); Centre of Excellence in Theoretical and Math Sciences, SOA University, Bhubaneswar - 751030 (India); Tripathy, B.B. [Dept. of Physics, Silicon Institute of Technology, Patia, Bhubaneswar - 751024 (India); Nayak, P. [Dept. of Physics, Sambalpur University, Jyoti Vihar, Burla (India)

    2012-04-15

    Coal and coal ash samples were characterized by particle induced X-ray emission spectroscopic technique. Sixteen elements, namely K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, As, Rb, Sr, Y and Pb were quantified in this study. Elements like K, Ca, Ti and Fe were present as major elements, whereas, other elements like V, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Rb, Sr and Pb were present in trace level. The enrichment ratio of different ash samples with respect to coal were also estimated and discussed. - Highlights: Black-Right-Pointing-Pointer Elemental analysis of coal and coal ash including pond ash is the first of its kind. Black-Right-Pointing-Pointer The enrichment ratio has been exclusively explained in the study. Black-Right-Pointing-Pointer Non-destructive PIXE analysis has been employed in this study and both major and trace elements has been estimated.

  17. Classification of coal by trace analysis using INAA-clusteranalysis and leaching of precipitator ash

    International Nuclear Information System (INIS)

    In The Netherlands the coal used for energy production is imported from many different countries. This implies a great variability of the (trace) element levels in the ash produced which in turn has implications for disposal and the preferred application in industry. To get hold of this variability in precipitator ashes obtained from coals of different origin a classification of coal was performed with clusteranalysis using the elemental composition (CLUSTAN-1C package). In addition to the measurement of elemental concentrations in coal and ash, leaching experiments were performed with precipitator ash. Elements which are leached appreciably are the halogens, SO42-, Mo, W, Cd and Hg. Arsenic and selenium are hardly leached from the alkaline ash studied

  18. 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.

  19. 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

  20. Mullitization of black coal fly ashes

    International Nuclear Information System (INIS)

    In this paper are presented the results of experiments focused on the study of thermal treatment influence of selected black coal fly ashes 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 phase's change of material occurred. At 1050 grad C, the decrease of amorphous phase was remarked, being transformed to the mullite and spinel. This information allow of the use examined fly ashes samples as the matrix for the mullite composites preparation providing the stoichiometric change of thermally treated mixture. (authors)

  1. Coal Ash Corrosion Resistant Materials Testing

    Energy Technology Data Exchange (ETDEWEB)

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

    2003-08-31

    In April 1999, three identical superheater test sections were installed into the Niles Unit No.1 for the purpose of testing and ranking the coal ash corrosion resistance of candidate superheater alloys. The Niles boiler burns high sulfur coal (3% to 3.5%) that has a reasonably high alkali content, thus the constituents necessary for coal ash corrosion are present in the ash. The test sections were controlled to operate with an average surface metal temperature from approximately 1060 F to 1210 F which was well within the temperature range over which coal ash corrosion occurs. Thus, this combination of aggressive environment and high temperature was appropriate for testing the performance of candidate corrosion-resistant tube materials. Analyses of the deposit and scale confirmed that the aggressive alkali-iron-trisulfate constituent was present at the metal surface and active in tube metal wastage. The test sections were constructed so that the response of twelve different candidate tube and/or coating materials could be studied. The plan was to remove and evaluate one of the three test sections at time intervals of 1 year, 3 years, and 5 years. This would permit an assessment of performance of the candidate materials as a function of time. This report provides the results of the evaluation of Test Section C, including the samples that remained in the Test Section for the full exposure period as well as those that were removed early. The analysis of Test Section C followed much the same protocol that was employed in the assessment of Test Section A. Again, the focus was on determining and documenting the relative corrosion rates of the candidate materials. The detailed results of the investigation are included in this report as a series of twelve appendices. Each appendix is devoted to the performance of one of the candidate alloys. The table below summarizes metal loss rate for the worst case sample of each of the candidate materials for both Test Sections A and C. The body of this report compares these for all of the samples in the test section. The 'Coal Ash Corrosion Resistant Materials Testing Program' is being conducted by The Babcock & Wilcox Company (B&W), the U.S. Department of Energy (DOE) and the Ohio Coal Development Office (OCDO) at Reliant Energy's Niles plant in Niles, Ohio to provide full-scale, in-situ testing of recently developed boiler superheater materials. Fireside corrosion is a key issue for improving efficiency of new coal fired power plants and improving service life in existing plants. In November 1998, B&W began development of a system to permit testing of advanced tube materials at metal temperatures typical of advanced supercritical steam temperatures (1100 F and higher) in a boiler exhibiting coal ash corrosive conditions. Several materials producers including Oak Ridge National Laboratory (ORNL) contributed advanced materials to the project. In the spring of 1999 a system consisting of three identical sections, each containing multiple segments of twelve different materials, was installed. The sections are cooled by reheat steam, and are located just above the furnace entrance in Niles Unit No.1, a 110 MWe unit firing high sulfur Ohio coal. In November 2001 the first section was removed for thorough metallurgical evaluation after 29 months of operation. The second section was removed in August of 2003. Its evaluation has been completed and is the subject of this report. The final section remains in service and is expected to be removed in the spring of 2005. This paper describes the program; its importance, the design, fabrication, installation and operation of the test system, materials utilized, and experience to date. This report briefly reviews the results of the evaluation of the first section and then presents the results of the evaluation of the second section.

  2. Basic properties and melting characteristics of coal ash

    Energy Technology Data Exchange (ETDEWEB)

    Unuma, H.; Takeda, S.; Tsurue, T.; Itoh, S.; Sayama, S.

    1985-10-01

    A study os reported of the ashes obtained from samples of 24 different coals (both Japanese and foreign). Ash properties and compositions were investigated by chemical analysis, X-ray diffraction, thermal gravimetric analysis and differential thermal analysis. Melting point tests were also carried out. A model ash prepared by adding various reagents to minerals exhibited melting behaviour closely analogous to that of coal ash. 8 references.

  3. Remediation of acid mines drainage using zeolites synthesized from coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Denise Alves Fungaro; Juliana de Carvalho Izidoro [Institute of Energy and Nuclear Research, Sao Paulo (Brazil). Center of Chemistry and Environment

    2006-07-15

    Coal material Zeolitic was synthesized from fly ashes (baghouse to filter fly ash and cyclone to filter fly ash) by hydrothermal alkaline activation. The potential application of the zeolitic product will be decontamination of waters from acid mines drainage was evaluated. The results showed that the dose of 30 g material L{sup -1} of zeolitic allowed to water you reach acceptable quality levels to after treatment. Both precipitation and cation-exchange you process accounted will be the reduction in the pollutant concentration in the treated waters.

  4. The determination of 210Pb in coal, coal ash, coal cinder and soil

    International Nuclear Information System (INIS)

    A radiochemical method is described for the determination of 210Pb in coal, coal ash, coal cinder and soil. The procedure includes sample dry ashing, leaching with HCl (1+1), separation with anion-exchange resin, purification as PbS precipitate and 210Bi beta counting. This method provides a good separation of 210Pb from other natural and artificial beta emitters. The half-life of 210Bi determined from the sample sources is 5.50d, which is close to the published value (5.01d). The lower limits of detection are 7.6 x 10-4 Bq/g for 10 g coal sample and 1.5 x 10-3 Bq/g for each and every 5 g of coal ash, coal cinder and soil samples. The 210Pb contents in the analyzed coal, coal ash, coal cinder and soil samples are 0.0316 +- 0.0097, 0.0712 +- 0.0760, 0.0109 +- 0.0035 and 0.0355 +- 0.0173 Bq/g and the chemical yields are 95.1% +- 2.5%, 97.2% +- 2.0%, 93.5% +- 1.6% and 95.7% +- 1.5% respectively. The enrichment factors (Ef) of 210Pb in coal ash, defined as the ratio of the content of 210Pb in coal ash to that in coal, range from 1.60 to 11.8 the method gives precision results. Four samples can be analyzed within 12 h (not including the time for counting). The technique is suitable for sample analysis on the environmental impact assessment of the coal-fuel power plant

  5. Ash transformation during co-firing coal and straw

    DEFF Research Database (Denmark)

    Zheng, Yuanjing; Jensen, Peter Arendt

    2007-01-01

    Co-firing straw with coal in pulverized fuel boilers can cause problems related to fly ash utilization, deposit formation, corrosion and SCR catalyst deactivation due to the high contents of Cl and K in the ash. To investigate the interaction between coal and straw ash and the effect of coal 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 importantly, by reaction with Al and Si in the fly ash. About 70-80% K in the fly ash appears as alumina silicates while the remainder K is mainly present as sulphate. Lignite/straw co-firing produces fly ash with relatively high Cl content. This is probably because of the high content of calcium and magnesium in lignite reacts with silica so it is not available for reaction with potassium chloride. Reduction of Cl and increase of S in the deposits compared to the fly ashes could be attributed to sulphation of the deposits.

  6. Study of the high-temperature reactions of coal ash

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Y.; Tsurue, T.; Yamada, K.; Takeda, S.; Unuma, H.; Sayama, S.; Itoh, S.

    1985-01-01

    A study is reported of changes in properties when coal ash is heated to its melting point. The object of this investigation was to obtain information of relevance to the waste product utilization of coal ash. Observations were made with an optical (polarizing) microscope, and microstructure analyzed using an X-ray microanalyzer and an Auger scanning microscope. By studying coal ash properties and the effects of high temperature processing conditions, it has been possible to obtain an indication of the processing required for utilizing ash in glass and in fertilizers. 4 references, 12 figures, 3 tables.

  7. Effect of chemical composition of coal ash on readings of radioisotope ash meters

    International Nuclear Information System (INIS)

    About 150 radioisotope ash meters, the readings of which are mostly used for operational control of processing operations, have been introduced at coal mining and coal processing facilities of the USSR. In addition to the significant advantages of these instruments (contactless instruments, speed, good representativeness of control), operation has also detected a number of series shortcomings, the principal one of which can be considered the effect of changes in ash composition on the measurement results. Since operation of nearly all radioisotope ash meters is based on the connection between effective atomic number of coal Z and its ash content, the distribution of light aluminosilicates and heavy ash-forming compounds of calcium and iron in the ash leads to changes of Z that are not correlated with ash content and, as a result, a significant error in control. Analysis of the effect of chemical composition of the coal ash on the readings of radioisotope ash meters was carried out on the basis of data from introduction and operation at the concentration plant of the Neryungrinsk Open-Pit Mine of the Yakutskugol Production Association of instruments to control coal ash content on line (RKTP-2) using the intensity of backscattered low-energy (60 keV) radiation as a function of ash content of the coal. The method of preliminary analysis of data on ash composition of coal proposed by the authors provides for evaluating the nonuniformity of the obtained data set, determinaormity of the obtained data set, determination of the minimal admissible number of calibrations from the standpoint of measurement error and finally establishment of the optimal sensitivity to ash content corresponding to these calibration

  8. 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

  9. Mullite whiskers derived from coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Park, Y.M.; Yang, T.Y.; Yoon, S.Y.; Stevens, R.; Park, H.C. [Pusan National University, Pusan (Republic of Korea). Dept. of Material Science and Engineering

    2007-04-15

    Alumina-deficient (Al{sub 2}O{sub 3}/SiO{sub 2} = 1.12, molar ratio), orthorhombic mullite whiskers with a diameter of 0.6-1.8 {mu}m (aspect ratio {gt} 30) have been manufactured by firing compacts of coal fly ash and NH{sub 4}Al(SO{sub 4}){sub 2}{center_dot} 12H{sub 2}O powders, with a small addition of NaH{sub 2}PO{sub 4}{center_dot}2H{sub 2}O, at 1300{sup o}C for 10h. The manufacturing process, the morphology, and structure of the whiskers are described.

  10. Iron Minerals in Coal, Weathered Coal and Coal Ash - SEM and Moessbauer Results

    International Nuclear Information System (INIS)

    The aim of the present investigation was to identify and quantify the iron mineral phases present in South African coal from various coal fields and in coal ash, after industrial and laboratory combustion processes, and to determine the changes that occur in these phases during weathering. Iron in coal is mainly associated with sulphur in the minerals pyrite and jarosite, whilst other iron-bearing minerals such as illite and ankerite also occur, but also occurs as a trace element in kaolinite, a major clay mineral present in coal. The amounts of these minerals vary considerably in coals from diverse origins and thus coal samples from six coal-producing areas in South Africa were studied by means of Moessbauer spectroscopy and SEM analyses. With the aid of Moessbauer spectroscopy, the iron-bearing minerals were identified in the coal, coal ash and weathered coal, whereas in the SEM analyses, apart from these minerals, the non-iron-bearing minerals were identified and found to be mainly quartz, clay minerals and carbonates. Differences in mineral composition were found between the coals from the different regions. Ash samples, obtained from the Lethabo electricity power plant, South Africa, were investigated and laboratory simulations were performed to obtain a comparable analysis of the industrial ash samples. At the high temperatures (?1400oC) of combustion in the power plant, fly ash and agglomerates are produced and the Moessbauer spectra resulted in twnd the Moessbauer spectra resulted in two poorly developed doublets, typical of glass. In the laboratory simulation, carried out at temperatures ranging from 200o to 1200oC it was clearly observed how the pyrite changed to hematite and finally was taken up in the glass in addition to the hematite that formed. The high amount of calcium present, identified by SEM analyses, resulted in the agglomeration occurring of the fly ash. The weathering products were also identified using the same techniques and it was noticed that the pyrite changed to a sulphate when the wet coal was exposed to air drying.

  11. Trace-element studies on South African coals and fly ash

    International Nuclear Information System (INIS)

    The application of wavelength dispersive XRF spectrometry to the determination of major and trace elements in South African coals, coal ash and fly ash has been investigated. Fourteen coals, the corresponding coal ash and 13 fly ash samples from three power stations have been analysed for sulphur and 27 inorganic trace elements. Also, petrographic and mineralogical analyses were made on the coal samples. The loss on ashing for various elements is also reported

  12. Trace elements of coal, coal ashes and fly ashes by activation analysis with shor-lived nuclides

    International Nuclear Information System (INIS)

    On irradiation with neutrons, some of the interesting trace elements in coal, coal ash and fly ash produce short-lived nuclides which may be determined - together with some of the matrix elements - by activation analysis. This enables the characterization of samples. To find out the distribution of elements in the gaseous or aerosol exhaust of fossil-fired power plants, the authors simulated the combustion in a quartz apparatus containing a cold trap, using the combustion temperature (780 deg C) employed for the standard ash determination. High Se values were found in the cold trap deposits of black coal from Poland. Halogens were also found in the deposits. (authors)

  13. Moessbauer Studies of Thermal Power Plant Coal and Fly Ash

    International Nuclear Information System (INIS)

    Iron-57 Moessbauer 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 Moessbauer and magnetic susceptibility studies on fly ash samples of Panipat (India) thermal power plant reported earlier.

  14. ? ray on-line ash monitor for coal

    International Nuclear Information System (INIS)

    For instrumented and automated coal dressing and briquetting processes to be operated under the optimum conditions, it is necessary to continuously measure the content of inconbustibles in coal (ash content) and to feed back the data to each process control system. To this end, the authors developed an on-line coal ash monitor of a two-radiation-source transmission type using the radioactive isotopes of 241Am and 137Cs. The structure and functions of the automatic ash content analyzing system is outlined in this report. The ash content A can be calculated from the measurement P, the ratio of the mass absorption coefficients of coal for 241Am and 137Cs, regardless of the thickness of the coal layer on the basis of the linear relationship between A and M. The ash content monitoring system consists of three sections, i.e., for source-detector, measurement and data processing. The signals from the detectors are sent to the counting unit in the measurement section after being amplified. The counting data are then fed to the processing unit, where the ash content is calculated. The counting data and the calculated ash content are shown in the display unit of the computer and the indicator of the measuring apparatus, outputted by the printer and indicated in analog meters. (Nogami, K.)

  15. 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

  16. Beneficiation of coal pond ash by physical separation techniques.

    Science.gov (United States)

    Lee, Sung-Joo; Cho, Hee-Chan; Kwon, Ji-Hoe

    2012-08-15

    In this study, investigations to develop a beneficiation process for separating coal pond ash into various products were undertaken. To this end, coal pond ash samples with different particle size ranges were tested in terms of their washability characteristics in a float-and-sink analysis. It was found that coal pond ash was heterogeneous in nature consisting of particles that varied in terms of their size and composition. However, it can be made more homogenous using a gravity separation method. Therefore, the possibility of separating coal pond ash was tested on standard equipment typically used for gravity concentration. To increase the separation efficiency, coal ash was separated according to the size of the particles and each size fraction was tested using equipment appropriate for the corresponding sizes. A hindered-settling column and a shaking table were tested for their ability to treat the 1.19 × 0.074 mm size fraction, and a Falcon concentrator was evaluated for its ability to treat the -0.074 mm size fraction. The results showed that various marketable products, such as lightweight aggregate, sand and high-carbon fuel, can be recovered from coal pond ash using simple physical separation techniques. PMID:22484657

  17. 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

  18. Leaching characteristics of heavy metals in fly ash from a Chinese coal-fired power plant

    Energy Technology Data Exchange (ETDEWEB)

    Xun Gong; Hong Yao; Dan Zhang; Yu Qiao; Lin Li; Minghou Xu [Huazhong University of Science and Technology Wuhan (China). State Key Laboratory of Coal Combustion

    2010-03-15

    China is the largest producer of coal ash in the world. Hydraulic ash transport systems are used in most coal-fired power plants, which lead to serious water pollution due to leaching of trace elements. The investigation on the leaching behavior of trace contaminants from coal ash is critical to environmental risk assessments. Batch leaching tests have been performed on the fly ash collected from each field of the electrostatic precipitator (ESP) of a coal-fired power plant to study the leaching characteristics of Cd, Cr, Pb and V. Leaching solutions included HCl solution of initial pH = 4 and NaOH solution of pH = 10. The liquid/solid (L/S) ratio was about 4:1 in all leaching tests. Fourteen leaching time intervals were selected, ranging from 15 min to 7 days. The results show that under studied experimental conditions, Cr has a relatively higher leachability in the acid-leaching solution, while Pb has a higher leachability in the alkaline solution. With the increase of leaching time, the leachability of Cr in each ash sample increases obviously. Within the same time interval, Cr in the ash sample from the last field of ESP has the highest leachability. The concentration of Cd in FA3 is the highest, but the leachability of Cd for FA3 is not the highest among the three ash samples. The concentration of V in FA1 is the highest; no increased trend with leaching time has been found in the experiment.

  19. Fly ash of mineral coal as ceramic tiles raw material.

    Science.gov (United States)

    Zimmer, A; Bergmann, C P

    2007-01-01

    The aim of this work was to evaluate the use of mineral coal fly ash as a raw material in the production of ceramic tiles. The samples of fly ash came from Capivari de Baixo, a city situated in the Brazilian Federal State of Santa Catarina. The fly ash and the raw materials were characterized regarding their physical chemical properties, and, based on these results; batches containing fly ash and typical raw materials for ceramic tiles were prepared. The fly ash content in the batches varied between 20 and 80 wt%. Specimens were molded using a uniaxial hydraulic press and were fired. All batches containing ash up to 60 wt% present adequate properties to be classified as several kinds of products in the ISO 13006 standard () regarding its different absorption groups (pressed). The results obtained indicate that fly ash, when mixed with traditional raw materials, has the necessary requirements to be used as a raw material for production of ceramic tiles. PMID:16540298

  20. Environmentally friendly use of non-coal ashes in Sweden.

    Science.gov (United States)

    Ribbing, C

    2007-01-01

    The Swedish Thermal Engineering Research Institute (Värmeforsk) initiated an applied research program "Environmentally friendly use of non-coal ashes", in 2002. The program aims at increasing knowledge on the by-products of energy production and their application. The goal of formulating technical and environmental guidelines and assessments is a major point of the program, which is supported by about forty authorities and private organisations. The programme has been divided into four areas: recycling of ashes to forests, geotechnical applications, use in landfilling, and environmental aspects and chemistry. Among all results obtained, the following progress is shown: *Evidence for the positive effects of spreading ashes on forest growth. *A proposal for environmental guidelines on the utilisation of ashes in construction. *A handbook for using non-coal fly ashes in unpaved roads. *Technical and environmental assessments of MSWI bottom ashes in road construction. *Development of the use of ashes with municipal wastewater sludge as a cover for landfills and mine tailings. *Use of ashes from bio-fuels in concrete and replacement of cement in stoop mining. *A method to classify those by-products from combustion that have mirror entries in the EWC as a hazardous or non-hazardous compound. The Ash Programme has also made it possible to increase knowledge on ashes as valuable materials, on quality assurance and on markets for recovered materials. PMID:17521898

  1. 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 T

  2. How toxic is coal ash? A laboratory toxicity case study.

    Science.gov (United States)

    Sherrard, Rick M; Carriker, Neil E; Greeley, Mark S

    2015-01-01

    Under a consent agreement among the Environmental Protection Agency (EPA) and proponents both for and against stricter regulation, EPA is to issue a new coal ash disposal rule by the end of 2014. Laboratory toxicity investigations often yield conservative estimates of toxicity because many standard test species are more sensitive than resident species, thus could provide information useful to the rule-making. However, few laboratory studies of coal ash toxicity are available; most studies reported in the literature are based solely on field investigations. This brief communication describes a broad range of toxicity studies conducted for the Tennessee Valley Authority (TVA) Kingston ash spill, results of which help provide additional perspective on the toxicity of coal ash. PMID:25348557

  3. Dry coal fly ash cleaning using rotary triboelectrostatic separator

    Energy Technology Data Exchange (ETDEWEB)

    Daniel Tao; Mao-ming Fan; Xin-kai Jiang [University of Kentucky, Lexington, KY (United States). Department of Mining Engineering

    2009-09-15

    More than 80 million metric tons of fly ash is produced annually in the U.S. as coal combustion by-product. Coal fly ash can be converted to value-added products if unburned carbon is reduced to less than 2.5%. However, most of fly ash is currently landfilled as waste due to lack of efficient purification technologies to separate unburned carbon from fly ash. A rotary triboelectrostatic separator has been developed and patented recently at the University of Kentucky with unique features. Several fly ash samples have been used to understand the effects of major process parameters on the separation performance. The results show that compared to existing triboelectrostatic separators, the rotary triboelectrostatic separator has significant advantages in particle charging efficiency, solids throughput, separation efficiency, applicable particle size range. 9 refs., 12 figs., 1 tab.

  4. Utilisation of coal ash to improve acid soil

    Directory of Open Access Journals (Sweden)

    Shigeru Kato

    2004-09-01

    Full Text Available The study on utilization of coal ash to improve acid soil was carried out in a greenhouse at the Land Development Regional Office 1, Pathum Thani Province, Central Thailand, from January-May 2003. Fly ash mixture (fly ash plus gypsum and lime at the proportion 5:4:1 and clinker ash mixture (clinker ash plus gypsum and lime at the proportion 5:4:1 were used as soil amendments at varying rates i.e., 0, 6.25,12.5, 18.75 and 25 t/ha to improve the soil. The aim of this study was to determine the effect of application of coal ash on acid soil and the growth of a vegetable (Chinese kale. Chinese kale cultivars were planted in a randomized complete block design with three replications. Pak Chong soil series (Ultisols was used as the growth medium. Twenty-day-old seedlings were transplanted in 270 pots (two plants per pot containing acid soil with different treatments of coal ash mixture which were as follows: 1 control, 2 fly ash mixture 6.25 t/ha, 3 fly ash mixture 12.5 t/ha, 4 fly ash mixture 18.75 t/ha, 5 fly ash mixture 25 t/ha, 6 clinker ash mixture 6.25 t/ha, 7 clinker ash mixture 12.5 t/ha, 8 clinker ash mixture 18.75 t/ha and 9 clinker ash mixture 25 t/ha. Chemical fertilizers were applied at the rate of 250 kg/ha using a grade of 15-15-15 of N, P and K, respectively. Plants were harvested 40 days after transplanting. Among the treatments, application of fly ashmixture at a rate of 25t/ha (4t/rai substantially increased soil pH up to 5.7. Fly ash was found more effective than clinker ash in increasing soil pH. The highest yield of Chinese kale was also obtained when fly ash mixture was applied at a rate of 25 t/ha followed by fly ash mixture at 18.75 t/ha and clinker ash mixture at 18.75 t/ha with an average yield per plant of 4.980, 3.743 and 3.447 grams, respectively. It can be concluded that the application of coal ash mixture, either fly- or clinker ash, at 18.75-25 t/ha (3-4 t/rai was the most effective in terms of plant yield. The use of coal ash mixture increased cation exchange capacity, base saturationpercentage and Ca, Mg and S contents in the soil as well as plant uptake of N. The concentrations of heavy metals in the soil (Cd, As, Co, Cr, Cu, Hg, Ni, Pb and Zn were found to be within permissible levels while Cd, Cr and Ni in the plants were at critical levels for health.

  5. 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. (authen the ponds and the adjacent river. (author)

  6. 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

  7. Community views about the health and exposure of children living near a coal ash storage site.

    Science.gov (United States)

    Zierold, Kristina M; Sears, Clara G

    2015-04-01

    Coal ash, a waste product generated from burning coal, is composed of small particles comprised of highly toxic elements. Coal ash particles contain heavy metals such as arsenic, lead, and mercury, as well as polyaromatic hydrocarbons and radioactive elements. Most coal ash is stored in landfills and ponds, often located in close proximity to low income communities. Currently, there are no federal regulations governing the storage and transport of coal ash; however the Environmental Protection Agency proposed a coal ash rule in 2010, which could designate coal ash as a hazardous waste. This is the first article to assess community impact from coal ash storage, by exploring parents' perceptions of their children's health and its relationship to chronic exposure to coal ash. This was a community-based study involving four neighborhoods adjacent to a large coal ash storage facility. Focus groups were conducted with community members and the transcripts were analyzed to identify themes regarding children's health, children's exposure to coal ash, and behaviors done to protect children from exposure. The majority of parents (85 %) reported that their children suffered from health conditions; specifically respiratory and emotional and behavioral disorders. Parents highlighted ways in which their children were exposed to coal ash, although many felt they were constantly exposed just by living in the area. Parents felt strongly that exposure to coal ash from the landfill is affecting the health and well-being of their children. Some parents attempted protective behaviors, but most parents felt helpless in reducing children's exposure. PMID:25204532

  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. SIROASH gauges for on-line determination of ash in coal

    International Nuclear Information System (INIS)

    Two new coal ash gauges have been developed for direct use on coal carrying conveyors and for use on sample by-lines. One depends on the absorption of low energy gamma-rays, and the second on the production of gamma-ray pairs. The accuracy for both gauges is better than 0.5% by weight ash for low-ash coals, and, for the Pair Production gauge, better than 1% for high-ash coals

  10. 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

  11. Use of lignite fly ash as an additive in alkaline stabilisation and pasteurisation of wastewater sludge

    Energy Technology Data Exchange (ETDEWEB)

    Kocaer, F.O.; Alkan, U.; Baskaya, H.S. [Uludag University, Bursa (Turkey). Faculty of Engineering & Architecture

    2003-10-01

    The possibility of using lignite fly ash in low doses for reducing the pathogen levels in wastewater sludge was investigated. The results showed that using fly ash alone in doses of 40%,80% and 120% (on a dry weight basis), did not produce an alkaline environment for an efficient removal of pathogens. However, using fly ash in conjunction with the minimum amount of quicklime may act as an effective way of fecal coliform removal in both alkaline stabilisation and pasteurisation processes. It was shown that using fly ash in doses of 80% and 120% in alkaline stabilisation and pasteurisation processes prevented the pH decays and regrowth of pathogens during 60 days of storage period. The results of the study confirmed that alkaline pasteurisation process produces a product which is more resistant to pH decays and regrowth of fecal coliforms compared to that of alkaline stabilisation. Consequently, the overall results of this study indicated that the minimum lime and fly ash dosages required to generate a Class B biosolid were 10-15% and 80%, respectively. On the other hand, heating sludge to 50{degree}C prior to the addition of 10-15% quicklime and 80% fly ash followed by further heating to 70{degree}C and then sustaining at this temperature for 30 minutes were sufficient to generate a Class A biosolid.

  12. COAL-FIRED POWER PLANT ASH UTILIZATION IN THE TVA REGION

    Science.gov (United States)

    The report gives results of a study: (1) to summarize (a) production of coal ash nationally and by TVA's 12 major ash-producing steam/electric power plants, and (b) the physical/chemical characteristics of coal ash that affect ash disposal and/or use; (2) to review reported metho...

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

    OpenAIRE

    Ayora, Carlos; Querol, Xavier; Moreno, N.; Alastuey, Andre?s; Juan Mainar, Roberto; Andre?s Gimeno, Jose? Manuel; Lo?pez Soler, A?ngel; 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 materia...

  14. Determination of the ash content of coal using annihilation radiation

    International Nuclear Information System (INIS)

    The ash content of coal can be determined by a simple technique based on the simultaneous measurement of 0.511 MeV annihilation radiation and Compton scattered radiation which result from irradiation of a coal sample with ?-rays of energy > 1.022 MeV. The technique has been tested by many laboratory measurements on 57 bulk coal samples, each weighing 100-200 kg, from three different areas of Australia. These measurements were performed using a 60Co source and 7.6 cm x 7.6 cm NaI(T1) detector in a backscatter geometry. The r.m.s. deviations between chemical laboratory ash and ash measured on the backscatter gauge were in the range of 0.46 to 1.37 wt.%. Compared with X-ray methods of ash analysis which depend on a single measurement proportional to the mass absorption coefficient, the annihilation radiation method has the advantages of less sensitivity to high Z elements such as Fe and Ca, less sensitivity to moisture variations and potentially greater depth penetration because of the higher energies used. The main potential applications of the technique are for the continuous analysis of coal on conveyor belts, in chutes or in hoppers. Such analysis is required mainly for the control of coal washeries and blending operations. (orig.)

  15. Procedure and means for measuring the coal content in quick ash

    Energy Technology Data Exchange (ETDEWEB)

    Peltonen, E.; Somerikko, A.; Viitanen, T.

    1985-02-12

    A procedure and an apparatus for continuously measuring the coal content of quick ash, ash being fed through a measuring chamber, through between measuring capacitor plates, the change of capacitance caused by the coal being measured, and a measuring signal being formed which characterizes the coal content of the ash.

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

    Directory of Open Access Journals (Sweden)

    Abdulhameed Umar Abubakar

    2012-11-01

    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.

  17. Experiments for the analysis of ash and sulphur of low-ash coal with radioisotope Fe-55

    International Nuclear Information System (INIS)

    For the purpose of the automation of coal preparation process, the experiment on the rapid analysis of ash and sulphur in low-ash coal was carried out at the Miike Coal Preparation Plant using radioisotope Fe-55 of 80ci. The Mnx ray from this radioisotope was irradiated to the surface of coal powder sample, and the back-scattered and the fluorescent X-ray was detected by a Xe-sealed proportional counter. The energy analysis was made with filters and pulse-height analyzers, and finally, the analytical values of ash and sulphur were calculated with the established regression equations. The results obtained are as follows. It took approximately 25 min from the automatic sampling of clean coal to the display of the calculated results. The accuracy of the regression equations for the clean coal of Miike was 0.2% for ash and 0.1% for sulphur. This method is also applicable to other low-ash coal than Miike, but in the case of extremely low-sulphur coal, the regression equation for ash should be established separately. The optimum X-ray analysis can be made when coal powder samples pass through a 0.25 mm mesh by 85 to 95%, and the moisture content is less than 1%. As the Ca content in ash is higher, the O/C atomic ratio of coal is larger, and the analytical value of ash is higher. (Kako, I.)

  18. 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

  19. An Evaluation on the Physical and Chemical Composition of Coal Combustion Ash and Its Co-Placement with Coal-Mine Waste Rock

    Directory of Open Access Journals (Sweden)

    Budi Sulistianto

    2012-07-01

    Full Text Available In the last few decades, the utilization of coal to generate electricity was rapidly increasing. Consequently, the production of coal combustion ash (CCA as a by-product of coal utilization as primary energy sources was increased. The physical and geochemical characteristics of CCA were site-specific which determined by both inherent coal-source quality and combustion condition. This study was intended to characterize the physical, chemical and mineralogical properties of a coal-combustion ash (CCA from a site specific power plant and evaluate the leachate characteristic of some scenario on the co-placement of CCA with coal-mine waste rock. The physical properties such as specific gravity, dry density, porosity and particle size distribution were determined. Chemically, the CCA sample is enriched mainly in silica, aluminum, iron, and magnesium along with a little amount of calcium and sodium which includes in the class C fly ash category. Moreover, it is found that the mineral phases identified in the sample were quartz, mullite, aragonite, magnetite, hematite, and spinel. Co-placement experiment with mudstone waste rock shows that the CCA, though it has limited contribution to the decreasing permeability, has important contributed to increase the quality of leachate through releasing higher alkalinity. Moreover, addition of CCA did not affect to the increase of the trace metal element in the leachate. Hence, utilization of CCA by co-placement with coal mine waste rock in the dumping area is visible to be implemented.

  20. 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...

  1. Characterization of carbon concentrates from coal-combustion fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Baltrus, J.P.; Wells, A.W.; Fauth, D.J.; Diehl, R.; White, C.M. [U.S. Department of Energy, Pittsburgh, PA (USA). National Energy Technology Laboratory

    2001-04-01

    A study of carbon concentrates separated by a number of different commercial and laboratory methods from various coal-combustion fly ashes was undertaken to determine what common and unique chemical and physical properties can be expected in such concentrates. The properties were determined using a variety of physical and spectroscopic characterization methods and then were compared among the carbon concentrates and in two cases with the properties of the unprocessed fly ashes. The class F fly ashes originated from a total of seven different utilities burning bituminous coals and underwent one of six different processing methods to produce the carbon concentrates, which contained from 24% to 76% carbon. Three different configurations of triboelectrostatic separators were used to produce the carbon concentrates in addition to two different flotation methods plus a proprietary carbon recovery process. The results showed that unburned carbon concentrates from fly ash have properties similar to most carbon blacks and would be poor replacements for activated carbon in adsorption processes unless they are activated in a separate step. The untreated carbon may have applications as a substitute for carbon black provided it could be obtained in sufficient purity. The results have implications for those who wish to use carbon concentrates from coal-combustion fly ashes in secondary markets, especially as sorbents and fillers. 41 refs., 6 figs., 3 tabs.

  2. Utilization of Atikokan coal fly ash in acid rock drainage control from Musselwhite Mine tailings

    International Nuclear Information System (INIS)

    Acid rock drainage (ARD) is the greatest environmental liability facing the mining industry. Mines produce acidic effluents that are generated from the chemical reaction of sulphide containing minerals and atmospheric oxygen. The effluents have a pH value as low as 2 to 4 and their movement is accompanied by heavy metals which damage the ecosystem. This paper described some of the ARD-preventing technologies that are under investigation. In particular, it examined the feasibility of using Atikokan coal fly ash (AFA) as a buffering material to control and mitigate the generation of ARD from reactive Musselwhite Mine gold mine tailings. Coal fly ash is the residue resulting from the combustion of coal at electric generating plants. It consists of organic and inorganic matter, including silica, alumina, iron and calcium oxide with various amounts of carbon. More than 40,000 tons of fly ash is generated each year from the Atikokan Generating Station located 190 km west of the mine, of which 80 per cent is used for concrete manufacturing. In this study, experiments were conducted to determine the physical, chemical and mineralogical properties of both the fly ash residue and mine tailings. Six kinetic column permeation tests were then performed to monitor the leaching properties of the fly ash and the coal fly ash-mine tailings mixtures to determine the hydraulic conductivities resulting from pozzolanic reactions. The potential impacts of the disposal of AFA and mine tailiacts of the disposal of AFA and mine tailings were also assessed. The study showed that the hydraulic conductivities of high-calcium AFA and the ash-tailings mixtures were greatly reduced upon contact with ARD. The pH of the pore fluid increased from acidic to alkaline. The concentration of regulated elements in the leachate from the ash-tailings mixtures were also below the limits set by the Ontario Ministry of Environment. The results indicate that AFA could mitigate the generation of ARD from reactive Musselwhite Mine gold mine tailings. 1 ref., 6 tabs., 10 figs., 1 appendix

  3. 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)

  4. Microwave-assisted sample preparation of coal and coal fly ash for subsequent metal determination

    Energy Technology Data Exchange (ETDEWEB)

    Srogi, K. [Inst. of Chemical Processing of Coal, Zabrze (Poland)

    2007-01-15

    The aim of this paper is to review microwave-assisted digestion of coal and coal fly ash. A brief description of microwave heating principles is presented. Microwave-assisted digestion appears currently to be the most popular preparation technique, possibly due to the comparatively rapid sample preparation and the reduction of contamination, compared to the conventional hot-plate digestion methods.

  5. Conversion of different ash content brown coal in fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Osipov, P.; Chernyavskiy, N.; Ryzhkov, A.; Remenuk, A. [Ural Federal Univ., Ekaterinburg (Russian Federation). Dept. of Thermal Power Plants; Dulienko, S. [National Academy of Science of Ukraine, Kiev (Ukraine). Coal Energy Technology Inst.

    2013-07-01

    Available equations used to determine combustion specific rate of coal-derived cokes describe the burning of carbon particles well enough but are not accurate in case of ash-containing coke particles combustion. This study is an attempt to account for the influence of both initial ash content and its increase in the course of carbon conversion in specific rate calculations. The results of experimental study of burn-out dynamics of Volchanskiy field (North Urals) brown coal and its coke with different ash content under conditions of fluidized bed combustion at impulse-type non-gradient reactor RSC-1 and dynamic installation Pyrolysis-M are summarized. Diffusion and heterogeneous (kinetic) components of carbon combustion rate are identified separately by using diffusion and kinetics equation with correction for carbon mass fraction in particles. Burning particle overheating values and heterogeneous combustion rate constants at different temperatures are estimated.

  6. Production of ceramics from coal fly ash

    OpenAIRE

    Angjusheva Biljana; Fidancevska Emilija; Jovanov Vojo

    2012-01-01

    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,Al)2O6] was formed. Ceramics with...

  7. Radioactive analysis of coal ash sampled from the east China area and simulative experiment for using coal ash in farmland

    International Nuclear Information System (INIS)

    Sampling from the electric power plants of Zhejiang, Fujian, Shandong, Jiangxi, Anhui and Jiangsu, 16 coal ash samples were measured respectively by HPGE ?-spectrometer analyzer. The results showed that the main composition of radioactive nuclide are 238U, 232Th, their daughter nuclides and 40K. The activity ratio of 238U, 232Th and 40K ranges from 75 Bq/kg to 284 Bq/kg, from 60 Bq/kg to 164 Bq/kg and from 120 Bq/kg to 738 Bq/kg, respectively. The simulated experiment on coal ash used to farmland showed that the activity ratio of natural radioisotope 226Ra and 228Ra in the simulated soil were 1.88 and 1.39 times higher than those in ordinary soil respectively when amount of the coal ash used was up to 525 t/hm2. The activity ratio of two nuclides in crop (rice, maize and wheat seed) grown in the farmland applied with coal ash and those of the ordinary farmland have no evident difference. The effect of edible security is not evident

  8. Laboratory determination of the ash content of some Australian coals using radioisotope techniques

    International Nuclear Information System (INIS)

    Two radioisotope techniques suitable for the rapid laboratory determination of the ash content of coal have been tested on unwashed coal samples from four Australian coal seams. In one technique, measurements of backscattered 238Pu L X-rays and iron K X-rays from finely ground coal samples have been combined to determine ash content in unwashed coals to +- 0.5 weight per cent ash for three seams and +- 0.9 weight per cent ash for the fourth. The second technique, which involves measurements of the transmission by the coal of narrow beams of 241Am 60 keV and 133Ba 356 keV ?-rays, requires less sample preparation. The ash was determined to within the range of 0.8 to 2.6 weight per cent for the four seams (unwashed coal). For washed coals, errors are expected to be <+-0.5 weight per cent ash

  9. Clean coal and high ash coal utilisation technology

    International Nuclear Information System (INIS)

    India is endowed with nearly 202 billion tonnes of coal compared to 765 million tonnes of oil and 707 billion cubic metre of natural gas. At the present rate of consumption, coal will last for 200 years compared to 24 years in case of oil and 23 years in case of natural gas. With environmental restriction on use of nuclear power, India will have to depend on coal as a primary source of energy for its sustainable growth even beyond 2020. This paper deals with the prospect of utilising indigenous coal with due consideration to environment friendliness. (author). 3 tabs

  10. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Motlep, Riho, E-mail: riho.motlep@ut.ee [Department of Geology, University of Tartu, Ravila 14A, 50411 Tartu (Estonia); Sild, Terje, E-mail: terje.sild@maaamet.ee [Estonian Land Board, Mustamaee tee 51, 10621 Tallinn (Estonia); Puura, Erik, E-mail: erik.puura@ut.ee [Institute of Technology, University of Tartu, Nooruse 1, 50411 Tartu (Estonia); Kirsimaee, Kalle, E-mail: kalle.kirsimae@ut.ee [Department of Geology, University of Tartu, Ravila 14A, 50411 Tartu (Estonia)

    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.

  12. 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 unstablcarbonation) of the aforementioned unstable phases into more stable forms, takes, at best, hundreds or even hundreds of thousands of years.

  13. 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

  14. Combustion characteristics of high ash South African coal reserves

    Energy Technology Data Exchange (ETDEWEB)

    R.C. Everson; P.D. Kalibantonga; H.W.J.P. Neomagus; N.J. Wagner [North-West University, Potchefstroom (South Africa). School of Chemical and Minerals Engineering

    2009-07-01

    An investigation was undertaken to determine the properties and combustion reactivities of typical high-ash coals (30% to 50% by weight) originating from many mining sites in South Africa, in order to generate information for the development of fluidised bed combustors. The coals were bituminous and of medium rank (reflectance 0.58%-0.78%) with compositions (organic/inorganic) within the following ranges (by volume), 7% - 66% pure inertinite, 2%-31% pure vitrinite, 11%-42% bi- and tri-macerites, 9%-33% carbominerites and 7%-34% minertite. A thermogravimetric analyser was used for the determination of the reactivities and different reaction models were evaluated. Raw coals were combusted in a reactive gaseous medium. The experimental conditions at which the combustion experiments were carried out were chosen to be similar to that used in fluidised bed combustion. Isothermal combustion experiments were conducted with 1 mm coal particles at atmospheric pressure (87.5 kPa) and at reaction temperature between 750{sup o}C and 900{sup o}C with a gas mixture consisting of 21 mole % oxygen in nitrogen. The initial devolatilisation period which was very rapid depended on the coal type and temperature and was distinctly different to the combustion period. Results from the combustion of the resulting chars only were examined and the dependence of the reactivities of the coals on the reaction temperature and properties of the parent coal were evaluated. Carbon conversion results at the higher temperatures were found to be very close to one another, which is characteristic of overall reactions controlled by diffusion mechanisms. Correlations of the reactivity with ash and inertinite contents were also obtained. A shrinking core model consisting of a combination of film diffusion, diffusion through the ash layer, and surface chemical reaction agreed very well with experimental results. 23 refs., 11 figs., 6 tabs.

  15. 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.

  16. 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...

  17. An investigation on radon exhalation from fly ash produced in the combustion of coal

    International Nuclear Information System (INIS)

    Fly ash is the end product of coal combustion and coal. Like most earthen materials it contains 238U the parent element of the uranium decay series which support several radioactive decay products including radon. Radon exhalation rate from fly ash produced by thermal power station has been measured and compared with that from different kinds of soil and from coal itself. It is observed that the radon exhalation rate from fly ash is less than that from soil and coal, although fly ash contains a higher concentration of uranium than typical soil. The addition of fly ash as an additive to soil does not significantly suppress radon exhalation from soil. (author)

  18. Synthesis of granular zeolitic materials with high cation exchange capacity from agglomerated coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Roberto Juan; Susana Hernandez; Jose Manuel Andres; Carmen Ruiz [Instituto de Carboquimica (CSIC), Zaragoza (Spain)

    2007-08-15

    Fly ash from coal combustion is a potential source of pollution and there is continuous interest in its recycling by converting it into products such as zeolitic materials for use in retaining pollutants. In this paper, production of granular zeolitic material from a commercially-unusable fine-fraction of a lightweight aggregate (LA) building material made from coal fly ash agglomerated with lime, by conventional alkaline activation is described. NaP1 zeolite, K-F zeolite, K-Phillipsite and K-Chabazite were synthesised. The process was optimised by combining four reaction parameters (temperature, alkali concentration, solution/fly ash ratio and reaction time). Zeolitic materials with the highest zeolite yields and cation exchange capacities were selected for future application in environmental processes. End-product zeolitic materials maintain its granular form and this could favour their use in some particular applications for environmental waste treatment (e.g. ionic exchange in column) without any further transformation stages. 21 refs., 6 figs., 6 tabs.

  19. 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.

  20. Substoichiometric isotope dilution analysis of tin in coal fly ash

    International Nuclear Information System (INIS)

    An accurate and precise analytical method for traces of tin by substoichiometric isotope dilution has been investigated. The present method consists of the extraction of tin(IV) as iodide into benzene, the complex formation of tin(IV) with the substoichiometric amount of salicylideneamino-2-thiophenol in the benzene phase. The reproducibility of the substoichiometric separation is satisfactorily good, and the determination of tin in microgram order can be expected. The high selectivity of this method has been ascertained by adding 17 foreign metals and 11 radioactive tracers to the tin(IV) solution. The present method has been applied to the determination of tin in environmental materials, NBS Coal Fly Ash (SRM 1633) and fly ash from coal-fired power plant in Japan

  1. Analysis of polynuclear aromatic hydrocarbons from coal fly ash

    International Nuclear Information System (INIS)

    The objective of this work is to compare various extraction and quantification techniques for the determination of adsorbed polynuclear aromatic hydrocarbons (PAHs) on coal ash. Aliquots of a 'clean' fly ash from coal combustion doped with four PAHs have been extracted, using three solvents, three methods and three GC/MS programs. Factorial analysis shows solvent to extert the greatest primary effect: CH2Cl2 > toluene much-gt o-xylene. Highest recoveries were obtained using the reflux slurry extraction procedure with CH2Cl2 and a relatively fast (20 degree C/min) temperature ramp to 310 degree C. With both CH2Cl2 and toluene solvents, ultrasonic assisted extraction affords the best repeatability

  2. 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.

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

    OpenAIRE

    Vukojevi? Vanja; Sabovljevi? Marko; Jovanovi? S.

    2005-01-01

    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 meta...

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

    OpenAIRE

    Aineto, Mo?nica; Acosta, Anselmo; Rinco?n Lo?pez, Jesu?s Mari?a; 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 ...

  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. Radioactivity of coals and ashes from Catala?zi coal-fired power plant in Turkey.

    Science.gov (United States)

    Aytekin, Hüseyin; Baldik, Ridvan

    2012-04-01

    The Çatala?z? coal-fired power plant (CFPP) is the Turkish CFPP that uses the hard coals produced in Zonguldak, located in the West Black Sea region of the country. Gamma-ray spectrometry was used to determine (226)Ra, (232)Th and (40)K contents in pulverised coal, bottom ash and fly ash samples. The natural radionuclide concentrations in pulverised coal ranged from 29 to 61 Bq kg(-1) for (226)Ra, from 32 to 55 Bq kg(-1) for (232)Th and from 229 to 414 Bq kg(-1) for (40)K. The fly ash fraction gave concentrations ranging from 80 to 98 Bq kg(-1) for (226)Ra, from 64 to 85 Bq kg(-1) for Th and from 754 to 992 Bq kg(-1) for (40)K, respectively. The enrichment factors from coal to fly ashes are 1.7, 2.24 and 2.6 for (232)Th, (226)Ra and (40)K, respectively. Therefore, it is advisable to monitor the environmental impact of the power plant. PMID:21632583

  8. Radioactivity of coals and ashes from Catalagzi coal-fired power plant in Turkey

    International Nuclear Information System (INIS)

    The Catalagzi 'dot-less' coal-fired power plant (CFPP) is the Turkish CFPP that uses the hard coals produced in Zonguldak, located in the West Black Sea region of the country. Gamma-ray spectrometry was used to determine 226Ra, 232Th and 40K contents in pulverised coal, bottom ash and fly ash samples. The natural radionuclide concentrations in pulverised coal ranged from 29 to 61 Bq kg-1 for 226Ra, from 32 to 55 Bq kg-1 for 232Th and from 229 to 414 Bq kg-1 for 40K. The fly ash fraction gave concentrations ranging from 80 to 98 Bq kg-1 for 226Ra, from 64 to 85 Bq kg-1 for Th and from 754 to 992 Bq kg-1 for 40K, respectively. The enrichment factors from coal to fly ashes are 1.7, 2.24 and 2.6 for 232Th, 226Ra and 40K, respectively. Therefore, it is advisable to monitor the environmental impact of the power plant. (authors)

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

    Directory of Open Access Journals (Sweden)

    Kae-Long Lin

    2013-07-01

    Full Text Available 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 concrete (1.458 W/mK. Water release (t1/2 value by the porous ceramic samples is decelerated by porous ceramic samples containing coal fly ash, due to the synergy effect of high water absorption by the coal fly ash and better than in the foamed glass material (4 h. Porous ceramic samples containing coal fly ash is highly promising for use in water absorption and retention applications.

  10. 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.

  11. 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

  12. Determining ash content in power coal by spectrometry of scattered gamma radiation

    International Nuclear Information System (INIS)

    Spectrometers are described used for determining ash content in coal of a grain size up to 10 mm. The results obtained showed that spectrometers of scattered gamma radiation could be employed. The amount of ash in coal, this up to 45% of the ash content could be directly assessed from the pulse rate pertaining to the peak of the measured spectrum or from the measured spectra ratios. The accuracy of ash content de--termination was +-2%. (J.B.)

  13. The future resources for eco-building materials: II. Fly ash and coal waste

    Energy Technology Data Exchange (ETDEWEB)

    Hui Li; Delong Xu [Xi' an University of Architecture & Technology, Xi' an (China). China State key Laboratory of Western Architecture & Technology

    2009-08-15

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

  14. Estimation of natural radioactivity in the ash generated from coal fired thermal power plants

    International Nuclear Information System (INIS)

    In the present study, coal, bottom ash and fly ash samples collected from three coal-fired power plants in India were measured for natural-U, 226Ra, 232Th and 40K by an HPGe ?-ray spectrometer. The results were compared with the available data from earlier studies in other countries. To assess the radiological hazard of fly ash and bottom ash used as building materials, the radium equivalent activity (Raeq) and external hazard index (Hex) are used in the study

  15. Novel materials based on microspheres from coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    A.G. Anshits; T.A. Vereshchagina; O.M. Sharonova; N.N. Anshits; E.V. Rabchevskii; O.A. Bayukov; S.V. Podoinitsyn [Institute of Chemistry and Chemical Technology (Russian Federation)

    2003-07-01

    Several morphological types of microspheres, comparable with synthetic ones by the composition and the properties, are generated during high-temperature thermochemical transformations while burning coal at the power plants. The three-step process for separation of ashes formed as a result of burning three different types of coals, including magnetic separation, hydrodynamic separation and granulometric classification, enabled us to obtain a wide range of stabilized products of magnetic microspheres and cenospheres with purity of 96-99% by the magnetic component. The physical and chemical properties as well as the morphology of the products obtained have been studied in detail by the methods of scanning electron microscopy (SEM), X-ray diffraction, Moessbauer and ESR spectroscopies. The general regularities of microsphere generation from a ferrosilicate melt in burning of coals of different types and the areas of application for the microspheres of different morphological types have been analyzed. The report describes the results of work in the following directions: Recovery of close-cut fractions of microspheres of stabilized composition from fly ashes of three power-generating coals of Russia. Morphological features of magnetic microspheres and cenospheres. Composition and physicochemical properties of close-cut fractions of microspheres of stabilized composition. Application areas of glass crystalline microspheres: catalysts of oxidative conversion of methane; microspherical porous glasses and sorbents on the basis of cenospheres; porous matrices for high-toxic waste disposal, in particular, for liquid radioactive waste. 15 refs., 6 figs., 1 tab.

  16. 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 concr...

  17. Errors of radioisotope ash-meters due to variations of coal density and iron content

    International Nuclear Information System (INIS)

    Presented is the technique of calculation of radioisotope ash-meter errors which permits to take into consideration correlations between coal density pho and ash content Asup(c), and between iron content in coal CsUb(Fe) and ash content. Results of parallel analysis of AsUp(c) and Csub(Fe) and rho in any arbitrary selected coal samples with different ash content, iron content and density can be initial data for the calculation. The calculation results are recommended to be used for ash-meter calibration

  18. Field studies of the leachability of aged brown coal ash.

    Science.gov (United States)

    Mudd, G M; Kodikara, J

    2000-09-15

    The environmental management of ash produced from the brown coal power stations of the Latrobe Valley region of Australia has been studied. Current practice consists of slurrying fly and bottom ash, a short distance to an ash disposal pond. However, storage facilities are approaching capacity and alternative ash management strategies are required in the near future. Initially, the ash produced within the power stations is known to possess a large soluble mass, which can leach rapidly to generate a saline leachate with minor trace metal content. After slurrying and deposition within the ash pond, it has been demonstrated that the soluble mass is significantly lower and the ash can be considered as aged or "leached" ash - a more benign waste that meets the criteria for fill material. In order to assess the long-term behaviour of the leached ash and its suitability for co-disposal in engineered sites within overburden dumps, two field cells were constructed and monitored over a period of 1 year. Each cell was 5 x 5 m in area, 3-m deep and HDPE lined with a coarse drainage layer and leachate collection pipe. The first cell only collected natural rainfall and was known as the Dry Cell. The second cell had an external tank of 5000 l installed (200-mm rainfall equivalent) and water was spray-irrigated regularly to simulate higher rainfall and accelerate the leaching process. The cumulative inflow and outflow for each cell has been calculated using a linear relationship and the leachate quality was monitored over time. The results demonstrate that the ash behaves as an unsaturated porous material, with the effect of evaporation through the profile being dominant and controlling the production of leachate. The leachate quality was initially moderately saline in both cells, with the concentration dropping by nearly 95% in the Wet Cell by the end of the field study. The leachate chemistry has been analysed using the PHREEQC geochemical model. The log activity plots of various species suggest the mineralogical controls on these species in leachate. The full results from this study are presented. PMID:10936533

  19. 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

    Scientific Electronic Library Online (English)

    Denise Alves, Fungaro; Juliana de Carvalho, Izidoro.

    2006-07-01

    Full Text Available [...] Abstract in english 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.

  20. 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)

  1. 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.

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

    Science.gov (United States)

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

    2009-09-15

    The waste low-calcium Czech brown coal fly ash represents a considerable environmental burden due to the quantities produced and the potentially high content of leachable heavy metals. The heterogeneous microstucture of the geopolymer M(n) [-(Si-O)(z)-Al-O](n).wH(2)O, that forms during the alkaline activation, was examined by means of microcalorimetry, XRD, TGA, DSC, MIP, FTIR, NMR MAS ((29)Si, (27)Al, (23)Na), ESEM, EDS, and EBSD. The leaching of heavy metals and the evolution of compressive strength were also monitored. The analysis of raw fly ash identified a number of different morphologies, unequal distribution of elements, Fe-rich rim, high internal porosity, and minor crystalline phases of mullite and quartz. Microcalorimetry revealed exothermic reactions with dependence on the activator alkalinity. The activation energy of the geopolymerization process was determined as 86.2kJ/mol. The X-ray diffraction analysis revealed no additional crystalline phases associated with geopolymer formation. Over several weeks, the (29)Si NMR spectrum testified a high degree of polymerization and Al penetration into the SiO(4) tetrahedra. The (23)Na NMR MAS spectrum hypothesized that sodium is bound in the form of Na(H(2)O)(n) rather than Na(+), thus causing efflorescence in a moisture-gradient environment. As and Cr(6+) are weakly bonded in the geopolymer matrix, while excellent immobilization of Zn(2+), Cu(2+), Cd(2+), and Cr(3+) are reported. PMID:19303704

  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. 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...

  5. Soil stabilisation using alkaline activation of fly ash for self-compacting rammed earth construction

    OpenAIRE

    Cristelo, Nuno; Glendinning, Stephanie; Miranda, Tiago F. S.; Oliveira, Daniel V.; Silva, Rui Andre? Martins Da

    2012-01-01

    This paper studies the effectiveness of alkaline activation of low-calcium fly ash on the improvement of residual granitic soils to be used on rammed-earth construction. Different liquid:solid ratios, alkali concentrations and Na2O : ash ratios were tested. Effect of calcium hidroxide, sodium chloride and concrete superplasticiser is also reported. Compressive strength up to 7 days at 60ºC was determined. Results show that, in terms of mechanical strength, there is an optimum value for the a...

  6. 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. Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4  

  7. 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.

  8. 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 ...

  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 28?m and of big particles(300 ?m. 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/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

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

    Directory of Open Access Journals (Sweden)

    Vukojevi? 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.

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

    International Nuclear Information System (INIS)

    Main obstacle using of fly ashes in building, that is its main consumer, is the residue of unburned coal; it is expressed of loss on ignition - 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 utilization of individual products obtained by modification. By means of corona separation, based on different conductivity of individual fly ash elements, it is possible to separate unburned coal particles. The fly ash sample from black coal burning in melting boiler that was deposited on fly ash deposit, content of LOI of dielectric particle 6,45 % at 61 % weight yield was achieved. In the samples taken from dry taking of fly ash the non-conducting product contained 7,72 % of LOI at 73 % of weight yield. (authors)

  15. Resource recovery from coal fly ash waste: an overview study

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, V.; Matsuda, M.; Miyake, M. [Okayama University, Okayama (Japan). Graduate School of Environmental Science

    2008-02-15

    Coal fly ash (CFA) is a useful byproduct of the combustion of coal. It is composed primarily of almost perfectly spherical aluminosilicate glass particles. This spherical characteristic and other characteristics of CFA should be exploited, rather than simply using CFA as inert filler for construction. Unfortunately, the presence of carbon residues and high levels of heavy metals has so far limited the uses of CFA. Forced leaching methods have been used to improve the technical and environmentally friendly qualities of CFA, but these processes do not seem to be economically viable. Actually, CFA is a major source of Si and Al for the synthesis of industrial minerals. Potential novel uses of CFA, e.g., for the synthesis of ceramic materials, ceramic membrane filters, zeolites, and geopolymers, are reviewed in this article with the intention of exploring new areas that will

  16. A light scattering method to discriminate between coal and fly ash particles dispersed in air

    International Nuclear Information System (INIS)

    This paper reports on a light scattering technique developed that can discriminate between cold coal and fly ash particles dispersed in air. The method is able to measure particle size, and so could also yield the separate size distributions within a mixture. The experimental system was tested using particles that were approximately spherical. Discrimination was demonstrated for four coal samples and their corresponding ash

  17. Boron determination in coal ash by fluoroborate ion-selective electrode

    Energy Technology Data Exchange (ETDEWEB)

    Wood, J.; Nicholson, K. [Robert Gordon University, Aberdeen (United Kingdom). Environmental Geochemistry Research Group, School of Applied Sciences

    1998-12-31

    The main sources of domestic boron in the environment are laundry products, sewage, agricultural chemicals and fertilisers, coal combustion, mining and glass and ceramics manufacturing. The concentration of boron in coal and coal ash can vary widely from 0.5-1144 mg/kg for coal and 23-1900 mg/kg in coal ash. Boron can be determined by several spectrophotometric techniques, ICPAES, IDMS, CE, FIA, FAES, PGAA and IC but all have drawbacks. The application of the fluoroborate ion-selective electrode (ISE) to the determination of soluble boron fractions in coal ash was examined. The electrode determines boron in the form of fluoroborate, and conversion of boron in samples and standards to this species is essential prior to analysis. The conversion of boron to fluoroborate was complete within 12 mins using 2 mL 40% hydrofluoric acid to 25 mL of sample. Boron was readily extractable in water even at ambient temperatures. An extraction time of 60 minutes at 75{degree}C was adopted. The amount of boron extracted was directly proportional to weight of ash added to water in the range 0.01-0.5 mg/mL. Maximum levels of water-soluble boron in coal ash and anthracite ash were 5.6 and 0.06 mgB/kg dry ash, respectively. Coal ash that had been exposed to the environment for 4 months contained little or no water-soluble boron. Coal dust produced no water-soluble boron. Spiking coal ash samples with 10 mg/L B showed a median recovery of 105.4%. Spiking anthracite samples with a 1 mg/L B sample produced a 98.7% recovery showing the ISE to be a good method for the determination of boron in coal ash leachates.

  18. Alkaline modified oil shale fly ash: optimal synthesis conditions and preliminary tests on CO2 adsorption.

    Science.gov (United States)

    Reinik, Janek; Heinmaa, Ivo; Kirso, Uuve; Kallaste, Toivo; Ritamäki, Johannes; Boström, Dan; Pongrácz, Eva; Huuhtanen, Mika; Larsson, William; Keiski, Riitta; Kordás, Krisztián; Mikkola, Jyri-Pekka

    2011-11-30

    Environmentally friendly product, calcium-silica-aluminum hydrate, was synthesized from oil shale fly ash, which is rendered so far partly as an industrial waste. Reaction conditions were: temperature 130 and 160°C, NaOH concentrations 1, 3, 5 and 8M and synthesis time 24h. Optimal conditions were found to be 5M at 130°C at given parameter range. Original and activated ash samples were characterized by XRD, XRF, SEM, EFTEM, (29)Si MAS-NMR, BET and TGA. Semi-quantitative XRD and MAS-NMR showed that mainly tobermorites and katoite are formed during alkaline hydrothermal treatment. Physical adsorption of CO(2) on the surface of the original and activated ash samples was measured with thermo-gravimetric analysis. TGA showed that the physical adsorption of CO(2) on the oil shale fly ash sample increases from 0.06 to 3-4 mass% after alkaline hydrothermal activation with NaOH. The activated product has a potential to be used in industrial processes for physical adsorption of CO(2) emissions. PMID:21943923

  19. Monitoring the species of arsenic, chromium and nickel in milled coal, bottom ash and fly ash from a pulverized coal-fired power plant in western Canada.

    Science.gov (United States)

    Goodarzi, F; Huggins, F E

    2001-02-01

    The concentration of As, Cr and Ni and their speciation (As3+;5+, Cr3+;6+ and Ni0;2+) in milled coal, bottom ash and ash collected by electrostatic precipitator (ESP) from a coal fired-power plant in western Canada were determined using HGAAS, ICP-AES and XANES. The chemical fractionation of these elements was also determined by a sequential leaching procedure, using deionized water, NH4OAC and HCI as extracting agents. The leachate was analyzed by ICP-AES. Arsenic in the milled coal is mostly associated with organic matter, and 67% of this arsenic is removed by ammonium acetate. This element is totally removed from milled coal after extraction with HCI. Arsenic occurs in both the As3+ and the As5+ oxidation states in the milled coal, while virtually all (>90%) of the arsenic in bottom ash and fly ash appears to be in the less toxic arsenate (As5+) form. Both Ni and Cr in the milled coal are extracted by HCI, indicating that water can mobilize Ni and Cr in an acidic environment. The chromium is leached by water from fly ash as a result of the high pH of the water, which is induced during the leaching. Ammonium acetate removes Ni from bottom ash through an ion exchange process. Chromium in milled coal is present entirely as Cr3+, which is an essential human trace nutrient. The Cr speciation in bottom ash is a more accentuated version of the milled coal and consists mostly of the Cr3+ species. Chromium in fly ash is mostly Cr3+, with significant contamination by stainless-steel from the installation itself. PMID:11253001

  20. 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.

  1. The concentration of naturally radioactive matter in coal and coal ash form the Saar region

    International Nuclear Information System (INIS)

    There was determined the content of naturally radioactive substances (40K, 226Ra, 228Th and 210Pb) in coal from the Saar region and in fly ash deposited in the electrofilters of the power plants. For this purposes four coal power plants were selected that were different from each other with respect to their technology and design. The measurements showed the specific concentrations of the radionuclides in the fly ash to be somewhat smaller than those found in similar investigations in other mining districts. The annual release rate of 226Ra, 228Th, and 210Pb, referred to the electric power of 1 GW, of the oldest power plant was ten times as high as that for the most modern coal power plant. The radiation exposure to be expected in the environment of these coal power plants is to be still determined by further investigations. Estimations for the environmental impact showed the additional radiation exposure by these discharges in the environment of the coal power stations to be within the range of variations for the exposure from natural radiation. (orig./HP)

  2. 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

  3. Spectrophotometric determination of phosphorus in coal and coal ash using bismuth-phosphomolybdate complex

    OpenAIRE

    Kaljevic, Vesna M.; IVANKA HOCLAJTNER-ANTUNOVIC; Todorovic, Marija R.; Mihajlovic, Randjel P.; Ignjatovic, Natasa R.

    2003-01-01

    A modified spectrophotometric method using the bismuth phosphomolybdate complex for the determination of phosphorus in coal and coal ash is suggested. Bismuth together with phosphate and molybdate forms a very stable complex in acid medium which turns blue (?molibdenum blue?) by reduction with ascorbic acid. The apparent molar absorptivity of PBiMo is 1.66x104 dm3 mol-1cm-1 at 720 nm and 2.10x104 dm3 mol-1cm-1 at 670 nm isobutyl methyl ketone (MIBK). Interference caused by the ions present ...

  4. Monitor of ash content of coal with X-ray source

    International Nuclear Information System (INIS)

    The coal ash monitor is used on-line to measure the ash content of raw, washed and blended coals. The instrument consists of a presentation unit and electronic unit. In the presentation unit a compact layer of coal is formed and there is also a radiation measuring system. A plutonium 238 source is used and the backscattered X-rays are detected by a proportional counter. The count rate is processed in the electronic unit and displayed as the ash percentage in the coal. A wide range of Polish coals was analysed. The monitor was tested in a power plant over the period of one year. The ash content in the coal analysed was in the range 5 to 50%. The gauge readings were compared with the pyrolysis results. An accuracy of 3.2% (95% confidence limit) was reached. These results were not corrected for the free moisture content which varied in the range 5 to 15 %. (author)

  5. 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.

  6. On-line determination of ash in coal using 'SIROASH' gauges

    International Nuclear Information System (INIS)

    The CSIRO has developed two SIROASH gauges for on-line determination of the ash content of coal. The first, based on low energy gamma-ray transmission (LET), is the preferred technique for low ash coals. It can be readily used directly on a conveyor belt provided the coal thickness exceeds about 50mm. In a two month plant trial the LET gauge determined the ash content of coal on the final product conveyor to +-0.45 wt%. Laboratory experiments on 1-2kg product, and in one case feed, coking coal samples determined ash to 0.31-0.40 wt %. The second technique, based on a high energy gamma-ray interaction called pair production (PP), is less sensitive to variations in ash composition and is the preferred technique for high ash coals. Laboratory tests on 50kg samples of high ash coals gave errors of 0.46-1.3 wt% ash compared to 1-2.2wt% for the LET gauge on the same samples

  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.

    2006-01-01

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

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

    OpenAIRE

    SAEED, KHALID; ISHAQ, Muhammad; Ilyas, Muhammad

    2011-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Kisi? 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.

  10. Study on surface morphology and physicochemical properties of raw and activated South African coal and coal fly ash

    Science.gov (United States)

    Mishra, S. B.; Langwenya, S. P.; Mamba, B. B.; Balakrishnan, M.

    South African coal and coal fly ash were selected as the raw materials to be used for study of their morphology and physicochemical properties and their respective activated carbons for adsorption applications. Coal and fly ash were individually steam activated at a temperature range of 550-1000 °C for 1 h in a muffle furnace using cylindrical stainless steel containers. Scanning electron micrographs revealed a change in surface morphology with more mineral matter available on the surface of the coal particles due to increased devolatilization. However, in the case of fly ash, the macerals coalesced to form agglomerates and the presence of unburnt carbon constituted pores of diameter between 50 and 100 nm. The BET surface area of coal improved significantly from 5.31 to 52.12 m 2/g whereas in case of fly ash the surface area of the raw sample which was originally 0.59 m 2/g and upon activation increased only up to 2.04 m 2/g. The chemical composition of the fly ash confirmed that silica was the major component which was approximately 60% by weight fraction. The impact of this study was to highlight the importance of using raw materials such as coal and a waste product, in the form of coal ash, in order to produce affordable activated carbon that can be used in drinking water treatment. This would therefore ensure that the quality of water supplied to communities for drinking is not contaminated especially by toxic organic compounds.

  11. A methodology to evaluate coal ash content using Siderite Moessbauer spectral area

    Energy Technology Data Exchange (ETDEWEB)

    G. Medina; J.A. Tabares; G.A. Perez Alcazara; J.M. Barraza [Universidad del Valle, Cali (Colombia). Department of Physics

    2006-03-15

    A methodology was used to evaluate Low Temperature Ash (LTA) and High Temperature Ash (HTA) through Moessbauer Spectroscopy (MS). Siderite was the only Moessbauer Spectral presenting a good correlation between the spectral area and the ash content obtained by LTA and HTA. The calibration curves obtained for HTA and LTA gave a correlation coefficient of 0.968 and 0.988, respectively. The LTA results present the best correlation, given that this process does not change the original mineral phases. This methodology was the advantageous for easily obtaining coal ash content, through curve ash content vs. MS area, without carrying out ashing processes. Short communication. 5 refs., 3 figs., 2 tabs.

  12. Thermogravimetric investigation on co-combustion characteristics of tobacco residue and high-ash anthracite coal.

    Science.gov (United States)

    Li, X G; Lv, Y; Ma, B G; Jian, S W; Tan, H B

    2011-10-01

    The thermal behavior of high-ash anthracite coal, tobacco residue and their blends during combustion processes was investigated by means of thermogravimetric analysis (20 K min(-1), ranging from ambient temperature to 1273 K). Effects of the mixed proportion between coal and tobacco residue on the combustion process, ignition and burnout characteristics were also studied. The results indicated that the combustion of tobacco residue was controlled by the emission of volatile matter; the regions were more complex for tobacco residue (four peaks) than for coal (two peaks). Also, the blends had integrative thermal profiles that reflected both tobacco residue and coal. The incorporation of tobacco residue could improve the combustion characteristics of high-ash anthracite coal, especially the ignition and burnout characteristics comparing with the separate burning of tobacco residue and coal. It was feasible to use the co-combustion of tobacco residue and high-ash anthracite coal as fuel. PMID:21865028

  13. 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 Ka?avský

    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.

  14. 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

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

    International Nuclear Information System (INIS)

    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, SiO2, Fe2O3 and Al2O3. Quantitative X-ray diffraction (XRD) analyses were carried out using an interactive data processing system (SIROQUANTTM) 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

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

    Science.gov (United States)

    Ural, Suphi

    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, SiO2, Fe2O3 and Al2O3. Quantitative X-ray diffraction (XRD) analyses were carried out using an interactive data processing system (SIROQUANT) 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. PMID:15752852

  17. 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)

  18. 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)

  19. 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 LiOH·H2O as precursors. The influences of various preparation conditions on Li2Al2Si3O10 forming were investigated. The results showed that the optimum additive amount of LiOH·H2O 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.

  20. 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 phosphates and sulphates. Iron oxides (mainly hematite and magnetite) are the main bottom ash products of the oxidation of pyrite, sometimes via intermediate 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

  1. To the method of increasing accuracy of radioisotope analysis of coal ash content

    International Nuclear Information System (INIS)

    The method of accuracy increase in radioisotopic analysis of coal ash content, which eliminates destabilizing effect of instability of element composition of coal ash, mainly iron and calcium, is suggested. The method consists in recording not only the dispersed constituent of the spectrum of secondary gamma radiation of iron 55 but in calcium fluorescent radiation (approximately 3.7 keV). Mean quadratic deviation of the method results from the data of chemical analysis constituted 0.32% at Ca amount variation of 2-12% and coal ash content 8-12%

  2. 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

  3. 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.

  4. 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

  5. Assessment of the effect of high ash content in pulverized coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Jayanti, S.; Maheswaran, K.; Saravanan, V. [Indian Institute of Technology, Madras (India). Dept. of Chemical Engineering

    2007-05-15

    The existing literature on CFD-based coal combustion modelling is applicable mainly for coals of low ash content and the calculations are done on an ash-free basis. In Indian coals, the ash content may be significantly higher, up to 40% or more. Studies reported in the literature show that the mineral matter in the coal may have a number of effects on the combustion characteristics. In the present study, a sensitivity analysis is performed, using the CFD code CFX of AEA Technology, on the likely effect of ash content on the char reactivity, oxygen diffusion rate for char combustion and on the radiative heat transfer parameters. The results show that the effect of enhanced char reactivity is negligible whereas reduced oxygen diffusion rates due to a thicker ash layer may result in a significant reduction in char oxidation rates with a resultant decrease in the peak temperature in the furnace. The global parameters such as the peak temperature and the flue gas temperature remain relatively insensitive to the presence of high ash content. These results are consistent with the experimental observations of Kurose et al. . Kurose, M. Ikeda, H. Makino, Combustion characteristics of high ash coal in pulverized coal combustion, J. Fuel 80 (2001) 1447-1455).

  6. Mercury in coal ash and its fate in the Indian subcontinent: A synoptic review

    International Nuclear Information System (INIS)

    In the Indian subcontinent power generation is mainly dependent upon the thermal power units and coal is burnt as a fuel for the production of heat and electricity. In India, bituminous and sub-bituminous coals are used which contain over 40% of ash. At present, 80-90 million tons of fly ashes are generated from 85 existing coal based thermal power plants. Coal contains trace metals of which mercury is most toxic for humans and aquatic fauna. The problem of mercury in the society is not new, but in recent years the Indian subcontinent has gained the reputation of being 'a dumping ground for mercury'. This study focuses on mercury in fly ash and its releases to the atmosphere and soils cross the country. The utilisation of coal ash in India is also addressed although it is still in its nascent stage. About 10% of produced fly ashes are used in India whereas in Western countries its use is typically over 70%. Regulations from India's Ministry of Environment and Forestry should increase coal fly ash utilisation, although this would require that cost-effective new technology is put to use. As to the release of Hg from ashes disposed of in the environment, the scarce literature suggests that this is negligible or zero, and less problematic than wet or dry deposition of Hg from flue gases. (author)

  7. A backscatter gamma-ray spectrometric method for the determination of ash in coal

    International Nuclear Information System (INIS)

    The method described is based on gamma-ray backscattering and utilizes the energy dependence of the backscattered gamma-ray peak. In the present work, a pair of windows established on either side of the backscattered gamma-ray peak were used to determine the apparent position of the peak which was strongly correlated with ash content. This technique requires only a four-channel spectrometer system. Laboratory tests carried out on 30 coal samples, with a wide range of ash composition, showed that ash content could be determined with a standard deviation of 1.5% ash for ash contents between 7 and 58%. (orig.)

  8. 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)

  9. 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.

  10. Hyperfine and X-ray studies of coal and coal ash

    International Nuclear Information System (INIS)

    X-ray diffraction and 57Fe Moessbauer hyperfine studies have been made to characterize the iron-bearing minerals present in some of the Indian coals. The minerals observed in a range of samples by Moessbauer study include siderite (FeCO3) and Fe3+, Fe2+-bearing silicate clay minerals such as illite. X-ray analysis also showed the diffraction lines of siderite and illite along with non-iron phases like quartz and calcium oxide. The effects of ashing (at 750deg C) were also studied by Moessbauer spectroscopy. (orig.)

  11. 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 (?LF) and percent frequency dependent susceptibility (?FD%) to be used to discriminate between coal fly ash and sediments native to the watershed. Riverbed samples with ?LF greater than 3.0 × 10?6 m3/kg, have greater than 15% ash measured by optical point counting. ?LF 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 ?LF. Measurement of ?LF 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 (?LF). ? The river sorts ash but maintains a ratio of clear: orange: black ash. ? ?LF measurements can predict % ash spheres from simple linear regression. ? ?LF 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

  12. 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, ?-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)

  13. 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)

  14. The influence of coal thickness change on dual-energy gamma-ray ash gauge reading

    International Nuclear Information System (INIS)

    For continuous measurement of coal-ash on a moving belt, intensity averaging causes the derived ratio of low-energy-gamma attenuation coefficient to that of high energy to be smaller than its real value. The difference is related to coal thickness and ash value and it is too great to be neglected. To reduce this thickness change related error, a count-rate level connected sampling method is suggested and its performance is verified by Monte-Carlo simulation

  15. Spectrophotometric determination of phosphorus in coal and coal ash using bismuth-phosphomolybdate complex

    Directory of Open Access Journals (Sweden)

    VESNA M. KALJEVIC

    2003-01-01

    Full Text Available A modified spectrophotometric method using the bismuth phosphomolybdate complex for the determination of phosphorus in coal and coal ash is suggested. Bismuth together with phosphate and molybdate forms a very stable complex in acid medium which turns blue (?molibdenum blue? by reduction with ascorbic acid. The apparent molar absorptivity of PBiMo is 1.66x104 dm3 mol-1cm-1 at 720 nm and 2.10x104 dm3 mol-1cm-1 at 670 nm isobutyl methyl ketone (MIBK. Interference caused by the ions present are within the tolerance limits (±2 %. Beer?s law is obeyed in the for concentration range to 0.6 mg/mL (aqueous solution and to 1.2 mg/mL P (MIBK. The sesitivity of the proposed method is 0.0078 mg/mL (aqueous solution and 0.0066 mg/mL (MIBK.

  16. Effect of coal ash on growth and metal uptake by some selected ectomycorrhizal fungi in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Ray, P.; Reddy, U.G.; Lapeyrie, F.; Adholeya, A. [Energy & Resources Institute, New Delhi (India)

    2005-07-01

    Six isolates of ectomycorrhizal fungi namely, Laccaria fraterna (EM-1083), Pisolithus tinctorius (EM-1081), Pisolithus tinctorius (EM-1290), Pisolithus tinctorius (EM-1293), Scleroderma verucosurn (EM-1283), and Scleroderma cepa (EM-1233), were grown on three variants of coal ash, namely electrostatically precipitated (ESP) ash, pond ash, and bottom ash moistened with Modified Melin-Norkans (MMN) medium in vitro. The colony diameter reflected the growth of the isolates on the coal ash. Metal accumulation in the mycelia was assayed by atomic absorption spectrophotometry. Six metals, namely aluminum, cadmium, chromium, iron, lead, and nickel were selected on the basis of their abundance in coal ash and toxicity potential for the present work. Growth of vegetative mycelium on fly ash variants and metal accumulation data indicated that Pisolithus tinctorius (EM-1290) was the most tolerant among the isolates tested for most of the metals. Since this isolate is known to be mycorrhizal with Eucalyptus, it could be used for the reclamation of coal ash over burdened sites.

  17. 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...

  18. Importance of the radiometric ash content determination by means of beta backscattering for coal transformation

    International Nuclear Information System (INIS)

    The radiometric method for ash content determination based on beta backscattering has been evaluated from the point of view of quality control and quality assurance in lignite mining and use of lignite. Applying the method, optimum control and distribution to generation of power, briquetting or coal transformation depending on ash content is possible

  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 L±250 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. 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)

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

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Y.P.; Wu, M.G.; Qian, J.X. [Institute of Industrial Control Technology, College of Info Science and Engineering, Zhejiang University, Hangzhou 310027 (China)

    2007-02-15

    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. (author)

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

    International Nuclear Information System (INIS)

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

  3. 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

  4. Coal ash transportation as paste-like, highly loaded pulps in Brazil: characterization and main features

    Energy Technology Data Exchange (ETDEWEB)

    Braganca, S.R.; Goncalves, M.R.F.; Bergmann, C.P.; Rubio, J. [Universidade Federal do Rio Grande do Sul, Porto Alegre (Brazil)

    2009-07-01

    The transportation of mineral coal ash in trucks with open top load compartments is inefficient, harmful to the environment, and costly. One solution to this problem is to utilize highly concentrated aqueous suspensions (paste) transportation systems, through steel pipes assisted by hydraulic pumping. In this study, coal ash (both fly ash and bottom ash), produced at a typical coal power plant (South Brazil), was utilized at different formulations, with mixtures of fly ash, bottom ash, and water (65%-70% solids content). These ash-bearing pulps were characterized in terms of their chemical and mineralogical composition, suspension pH that varied with the presence of Ca-bearing minerals, particle size distribution, and rheological behavior. Ash samples were distributed in fine, mean, and coarse sizes, facilitating the particles packing, diminishing voids, and contributing to the formation of paste with good consistency. The ash suspensions (32% water content) did not show compression strength and were plastically deformed after 48 hours of water addition. This behavior indicates that there were no chemical reactions, or pozzolanic activity, and that the particle interactions were mainly due to electrostatic forces and dispersions forces.

  5. ANALYSIS OF FLY ASH PRODUCED FROM COMBUSTION OF REFUSE-DERIVED FUEL AND COAL MIXTURES (JOURNAL VERSION)

    Science.gov (United States)

    Mixtures of coal and refuse-derived fuel (RDF) were burned and the fly ash was collected and analyzed for concentration trends with respect to RDF/coal ratio and particle size. RDF contributes more Cs, Mn, Sb, and Pb to the fly ash while coal contributes greater amounts of As, Br...

  6. EFFECT OF COAL ASH ON THE MORPHOLOGICAL, THERMAL AND MECHANICAL PROPERTIES OF POLY(METHYL METHACRYLATE

    Directory of Open Access Journals (Sweden)

    MUHAMMAD ISHAQ

    2012-03-01

    Full Text Available Composite materials of Coal ash/ Poly(Methyl Methacrylate (ash/PMMA were prepared/synthesized and their properties were studied by scanning electron microscopy (SEM, polarized optical microscopy (POM, differential scanning calorimetry (DSC, thermogravimetric analyzer (TGA and universal testing machine (UTM. The morphological study presented that the ash particles were well dispersed and embedded within the PMMA matrix. The DSC thermograms showed that the melting temperature (Tm of pure PMMA is about 166 ºC which was shifted towards lower temperature when ash were incorporated in the polymer matrix. The mechanical properties of the ash/PMMA composites were enhanced up to an optimum level (ash 3 wt % and then decreased at higher incorporation of large quantity of filler. The TGA thermograms indicated that the thermal stability of the ash/PMMA composite was enhance significantly than pure PMMA.

  7. EFFECT OF COAL ASH ON THE MORPHOLOGICAL, THERMAL AND MECHANICAL PROPERTIES OF POLY(METHYL METHACRYLATE)

    Scientific Electronic Library Online (English)

    MUHAMMAD, ISHAQ; KHALID, SAEED; MUHAMMAD, SHAKIRULLAH; IMTIAZ, AHMAD; TAYYIBA, REHMAN.

    2012-03-01

    Full Text Available Composite materials of Coal ash/ Poly(Methyl Methacrylate) (ash/PMMA) were prepared/synthesized and their properties were studied by scanning electron microscopy (SEM), polarized optical microscopy (POM), differential scanning calorimetry (DSC), thermogravimetric analyzer (TGA) and universal testing [...] machine (UTM). The morphological study presented that the ash particles were well dispersed and embedded within the PMMA matrix. The DSC thermograms showed that the melting temperature (Tm) of pure PMMA is about 166 ºC which was shifted towards lower temperature when ash were incorporated in the polymer matrix. The mechanical properties of the ash/PMMA composites were enhanced up to an optimum level (ash 3 wt %) and then decreased at higher incorporation of large quantity of filler. The TGA thermograms indicated that the thermal stability of the ash/PMMA composite was enhance significantly than pure PMMA.

  8. Evaluation of environmental stress imposed by a coal-ash effluent: Wisconsin power plant impact study

    Energy Technology Data Exchange (ETDEWEB)

    Webster, K.E.; Forbes, A.M.; Magnuson, J.L.

    1985-06-01

    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 stream, the ash pit drain. To test the hypothesis that habitat avoidance could account for declines in macroinvertebrate density observed after discharge began, drift rates of two species were measured in laboratory streams containing combinations of reference and coal-ash-modified substrate and water. Contrary to the hypothesis, drift was uniformly lower in laboratory streams containing modified substrate and/or water compared to the reference condition for Gammarus pseudolimnaeus and Asellus racovitzai.

  9. Natural radionuclide content of some U.K. coals and ashes

    International Nuclear Information System (INIS)

    For coal burnt by the CEGB at Eggborough and Drax Power Stations the average concentrations of radioactivity in coal are 20 Bq Kg-1 for both U-238 and Th-232 series and 260 Bq Kg-1 for K-40. The ash fraction passing through the ash precipitator gave values for U-238, Th-232 and K-40 of 110, 80 and 1100 Bq Kg-1 respectively. These studies have further shown that there is no significant enhancement of radioactivity on to the ash passing through the precipitators and entering the environment. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-01-01

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

  11. Chemical and petrographical characterization of feed coal, fly ash and bottom ash from the Figueira Power Plant, Parana, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Levandowski, Janaina; Kalkreuth, Wolfgang [Instituto de Geociencias, UFRGS, Av. Bento Goncalves, 9500, 91501-970 Porto Alegre, RS (Brazil)

    2009-01-31

    The aim of the present study is the petrographic and chemical characterization of the coal at the Figueira Power Plant, Parana, Brazil, prior and after the beneficiation process and the chemical characterization of fly and bottom ashes generated in the combustion process. Petrographic characterization was carried out through maceral analysis and vitrinite reflectance measurements. Chemical characterization included proximate analysis, determination of calorific value and sulphur content, ultimate analysis, X-ray diffraction, X-ray fluorescence, Inductively Coupled Plasma - Mass Spectrometry (ICP-MS) and Inductively Coupled Plasma - Atomic Emission Spectrometry (ICP-AES) analysis, and determination of Total Organic Carbon (TOC) content. Vitrinite reflectance analyses indicate a high volatile B/C bituminous coal (0.61 to 0.73% Rrandom). Maceral analyses show predominance of the vitrinite maceral group (51.6 to 70.9 vol.%, m.m.f). Except of the Run of mine (ROM) coal sample, the average calorific value of the coals is 5205 kcal/kg and ash yields range from 21.4 to 38.1 wt.%. The mineralogical composition (X-ray diffraction) of coals includes kaolinite, quartz, plagioclase and pyrite, whereas fly and bottom ashes are composed by mullite, ettringite, quartz, magnetite, and hematite. Analyses of major elements from coal, fly and bottom ashes indicate a high SiO{sub 2}, Al{sub 2}O{sub 3}, and Fe{sub 2}O{sub 3} content. Trace elements analysis of in-situ and ROM coals by ICP-MS and ICP-AES show highest concentration in Zn and As. Most of the toxic elements such as As, Cd, Cr, Mo, Ni, Pb, and Zn are significantly reduced by coal beneficiation. Considering the spatial distribution of trace elements in the beneficiated coal samples, which were collected over a period of three months, there appears to be little variation in Cd and Zn concentrations, whereas trace elements such as As, Mo, and Pb show a larger variation. In the fly and bottom ashes, the highest concentrations of trace elements were determined for Zn and As. When compared with trace element concentrations in the feed coal, fly ashes show a significant enrichment in most trace elements (As, B, Be, Cd, Co, Cr, Cu, Li, Mn, Mo, Ni, Pb, Sb, Tl, and Zn), suggesting a predominantly volatile nature for these elements. In contrast, Sn is distributed evenly within the different ash types, whereas U shows depleted concentration in both bottom and fly ash samples. According to the International Classification of in-seam coals the Cambui coals are of para/ortho bituminous rank of low grade (except for the ROM sample), and are characterized by the predominance of vitrinite macerals. (author)

  12. 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.

  13. Results of radiometric ash-content measurements at the Dudar coal mine, Hungary

    International Nuclear Information System (INIS)

    The regression analysis of the results of calorimetric and radiometric ash-content measurements of 1239 coal samples have shown that the calorific values which cannot be measured easily with traditional means can be approximated reasonably from the more easily measured radiometric data. The introduction of the radiometric measurements can be recommended for coal deposits. (author)

  14. Solidification of coal fly ash using hydrothermal processing method

    Energy Technology Data Exchange (ETDEWEB)

    Jing, Z.; Matsuoka, N.; Jin, F.; Yamasaki, N.; Suzuki, K.; Hashida, T. [Tohoku University, Miyagi (Japan). Graduate School for Environmental Studies

    2006-03-15

    Solidification of Coal Fly-ash (CFA) has been carried out using a hydrothermal processing method. In the hydrothermal processing, the CFA was first compacted in a mold at 20 - 50 MPa, and then hydrothermally cured in an autoclave. The hydrothermal curing was performed at 150 - 250{sup o}C for 15 - 60 h. The experimental results showed that NaOH solution, Ca(OH){sub 2} content, compaction pressure, autoclave curing temperature and time significantly affected the strength of solidified bodies. The most important strength-producing constituent in the solidified bodies produced with CFA was tobermorite, or tobermorite-like calcium silicate hydrate. When the CaO/SiO{sub 2} ratio of the starting material was close to 0.83, tobermorite readily formed and the formed tobermorite enhanced the strength of solidified bodies. The tensile strength determined by the Brazilian test reached more than 10 MPa under the hydrothermal processing. As such, the hydrothermal processing method may provide a high potential for recycling CFA on a large scale.

  15. Zeolite formation from coal fly ash and its adsorption potential

    Energy Technology Data Exchange (ETDEWEB)

    Duangkamol Ruen-ngam; Doungmanee Rungsuk; Ronbanchob Apiratikul; Prasert Pavasant [Chulalongkorn University, Bangkok (Thailand). Department of Chemical Engineering

    2009-10-15

    The possibility in converting coal fly ash (CFA) to zeolite was evaluated. CFA samples from the local power plant in Prachinburi province, Thailand, were collected during a 3-month time span to account for the inconsistency of the CFA quality, and it was evident that the deviation of the quality of the raw material did not have significant effects on the synthesis. The zeolite product was found to be type X. The most suitable weight ratio of sodium hydroxide (NaOH) to CFA was approximately 2.25, because this gave reasonably high zeolite yield with good cation exchange capacity (CEC). The silica (Si)-to-aluminum (Al) molar ratio of 4.06 yielded the highest crystallinity level for zeolite X at 79% with a CEC of 240 meq/100 g and a surface area of 325 m{sup 2}/g. Optimal crystallization temperature and time were 90{sup o}C and 4 hr, respectively, which gave the highest CEC of approximately 305 meq/100 g. Yields obtained from all experiments were in the range of 50-72%. 29 refs., 5 tabs., 7 figs.

  16. Interaction between iron-based oxygen carrier and four coal ashes during chemical looping combustion

    International Nuclear Information System (INIS)

    Highlights: • Some ash species, such as Fe2O3 or CaSO4, can function as oxygen carriers and extend the reduction time. • The duration of reducing Fe2O3 to Fe3O4 in the fluidized bed was related to the chemical composition of the ash. • Most coal ashes decreased the carrier’s reactivity except for the ash mainly composed of CaSO4. • Sintering and agglomeration was found in the presence of ash, except in the case of lignite ash enriched in CaO. • Ash deposition and the formation of Fe2SiO4 are the most likely reasons for ash’s effect on reactivity and agglomeration. - Abstract: Chemical looping combustion (CLC) is a novel technology with inherent CO2 capture, especially for solid fuels. The existence of ash in solid fuels is one major challenge for CLC technology development. In this work, interaction between an iron-based oxygen carrier and four different types of coal ash was studied in a laboratory-scale fluidized reactor. Different factors – the ash component, the redox cycle number, and the ash size – were taken into account. Chemical composition of the ash had effect on the reduction time from Fe2O3 to Fe3O4 in the fluidized bed. The presence of reactive components (such as Fe2O3 and CaSO4) in the ash, functioning as oxygen carriers, extended the reduction time. However, the chemical combination between the ash contents and the carrier can shorten the reduction time. The effect of ash on the carrier’s reactivity depended on the ash type. Most ashes decreased the reactivity of the carrier, except the ash mainly composed of CaSO4 which showed an increased reactivity due to the deposited reactive CaSO4. The effect of ash on decreasing the carrier’s reactivity increased with the cycles. Meanwhile, the larger ash (900–1000 ?m) corresponded to a higher CO conversion, and thus had less effect on the reactivity than the smaller ash (300–400 ?m). This occurrence can be attributed to the non-uniform solid–solid contact between the larger ash and the carrier. Sintering and agglomeration of the carrier particles occurred in the existence of most ashes, except the lignite ash enriched in CaO. Ash deposition and the formation of new compounds were detected. One common compound formed in the presence of SiO2-rich ash was Fe2SiO4, which has a low melt point (1170 °C) and a low thermal conductivity with a greater adhesion. The physical ash deposition and the formation of Fe2SiO4 through chemical reactions were proposed to be the main reasons for the effect of ash on the carrier’s reactivity and the occurrence of sintering and agglomeration. The existence of ash not only has impact on the carrier’s reactivity, but also causes solid fluidization disturbances. More effort is deserved to put into the ash-related issue in solid fuel CLC

  17. 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 Liase 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)

  18. 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 dem(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

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

    Science.gov (United States)

    Montes-Hernandez, G; Pérez-López, 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

  20. Determination of ash content in coal by the forward-scattering method of low-energy gamma radiation

    International Nuclear Information System (INIS)

    The paper describes a method for determination of ash content in coal, based on the forward-scattering phenomenon of low-energy gamma radiation. The paper evaluates the effect of measuring geometry, granulation, mass, sample packing and chemical constitution of coal on the accuracy of measured ash content in coal. There is given a new manner to calculate ash content that uses some parameters of the forward-scattered gamma radiation spectrum. (author)

  1. A technique for measuring the ash content of coal in a tailings stream

    International Nuclear Information System (INIS)

    A technique is described for developing an on-line instrument measuring the ash content of coal in a coal washery tailings stream. The method employs two radioisotope-detector systems, a 137Cs density transmission gauge and a Compton backscatter x-ray gauge with 109Cd. To evaluate the technique under typical plant conditions, a full-scale slurry measuring loop was constructed. The accuracy of the ''dry basis'' ash measurement, in a measurement time of 500 s was +- 4% ash (95% confidence level) for an ash range from 48 to 66% ash with the solids content varying from 18 to 35%. A calibration procedure is described which requires no knowledge of the values of the solids contents of the slurries used for calibration. (author)

  2. 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.

  3. 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

  4. Determination of pit-coal ash content with the use of an (?,n) neutron source

    International Nuclear Information System (INIS)

    Activation with fast neutrons from a Pu/Be source enables the 28Si(n, p)28Al and 27Al(n, p)27Mg reactions to be utilized. Seventy-two samples of pit coals with ash contents ranging from 3 to 40% were measured. The calibration function between ash content and both 1.78 and 0.84-MeV ?-ray counts was linear. The standard deviation was 0.9% for a 17% ash content and 1.4% over the whole range of ash contents. Comparison with rapid combustion and fluorescence scattering methods is discussed. (Auth.)

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

    OpenAIRE

    Kovács Ferenc; Mang Béla

    2002-01-01

    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...

  6. 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)

  7. Prospects of dry beneficiation of Indian high ash non-coking coal - a review

    Energy Technology Data Exchange (ETDEWEB)

    Biswal, S.K.; Sahu, A.K.; Reddy, P.S.R.; Parida, A.; Misra, V.N. [Regional Research Lab., Bhubaneswar (India)

    2003-02-01

    There is an urgent need for awareness in India for improving coal quality in the emerging environment. The technology for beneficiation, either dry or wet methods based on the characteristics of Indian coal is highly needed at the present scenario in coal industry. In this paper, the prospects of dry beneficiation of Indian high ash non-coking coal are highlighted. According to the process feasibility and cost comparison of different processes, magnetic separation and air dense medium fluidised bed separator are most likely processes to be economically viable for coal preparation. 13 refs., 9 figs., 2 tabs.

  8. Pipeline design for hydraulic backfilling of coal mines with use of fly ash and fly ash-bottom ash mixture at high concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Parida, A.; Panda, D.; Senapati, P..; Mishra, R.N. [Regional Research Laboratory (CSIR), Bhubaneswar (India)

    2003-07-01

    Design of pipelines to handle fly ash and fly ash-bottom ash mixtures at high concentrations for backfilling purpose is investigated. Fly ash and bottom ash samples from the Captive Power Plant, NALCO, Angul, Orissa, were mixed with water to form a thick homogenous vehicle with non-Newtonian behaviour. The slurry is for transport from the surface to underground coal mines. The concentration of the ash slurry is in the range of 60-65% by weight and the fraction of bottom ash in the mixture varies from 0 to 40%. The rheological parameters of the slurry which indicate pseudoplastic power law behaviour are used to evaluate the head loss in pipelines having diameters varying from 100 to 300 mm. The results indicate that at a particular concentration, the slurry head loss decreases with increasing fraction of bottom ash in the mixture. Thus addition of bottom ash has a beneficial effect in reducing head requirement. For the backfilling system, full-flow conditions have been considered and the effects of pipe diameter, solids weight concentration and bottom ash fraction on the H/L ratio are determined. Since the high concentration ash slurry can be conveniently transported under laminar flow conditions, the calculations have been carried out at laminar flow velocities of 0.4 m/sec to 2.0 m/sec. From the computed results, the design plots have been formulated which indicate the solids backfilling rates as a function of H/L ratio for different pipe sizes and transport velocities at a given solids concentration. 10 refs., 9 figs., 1 tab.

  9. Behaviour of coal mineral matter in sintering and slagging of ash during the gasification process

    OpenAIRE

    Matjie, Ratale Henry; French, David; Ward, Colin R.; Pistorius, Petrus Christiaan; Li, Zhongsheng

    2011-01-01

    The mineral matter in typical feed coals used in South African gasification processes and the ash derived from gasifying such coals have been investigated using a variety of mineralogical, chemical and electron microscope techniques. The mineral matter in the feed coals consists mainly of kaolinite, with minor proportions of quartz, illite, dolomite, calcite and pyrite plus traces of rutile and phosphate minerals. The calcite and dolomite occur in veins within the vitrinite macerals, and are ...

  10. 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)

  11. Behaviour of coal ashes for pulverised coal injection at high temperatures in relation to their chemical and mineralogical composition - experimental and computational analysis

    Energy Technology Data Exchange (ETDEWEB)

    Bagatini, M.C.; Klug, J.L.; Heck, N.C.; Osorio, E.; Vilela, A.C.F.; da Cruz, R. [Universidade Federal do Rio Grande do Sul, Porto Alegre (Brazil)

    2009-11-15

    The selection of coals for pulverised coal injection usually consists of evaluating the carbonaceous matter. However, the reduction of permeability in the lower section of the blast furnace with high rates of pulverised coal injection can be associated with remaining ashes from the coal combustion process. The aim of this work is to evaluate the behaviour of coal ashes at high temperatures in relation to their chemical and mineralogical composition. These ashes were submitted to the following analysis: chemical (X-ray fluorescence), mineralogical (X-ray diffraction), fusibility (heating microscopy) and viscosity (rotational viscometer). The software FactSage was also used to evaluate the behaviour of coal ashes. It was observed that samples present different chemical and mineralogical compositions, reflecting in the fusibility and viscosity of ashes. Their proportions and relevant phases were determined by computational thermodynamics and also related to the experimental work.

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

    Science.gov (United States)

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

    2010-08-01

    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, with Hg capture increasing with an increase in surface area. The latter is influenced by the rank of the feed coal, with carbons derived from the combustion of low-rank coals having a greater surface area than carbons from bituminous- and anthracite-rank coals. The chemistry of the feed coal and the resulting composition of the flue gas enhances Hg capture by fly ash carbons. This is particularly evident in the correlation of feed coal Cl content to Hg oxidation to HgCl2, enhancing Hg capture. Acid gases, including HCl and H2SO4 and the combination of HCl and NO2, in the flue gas can enhance the oxidation of Hg. In this presentation, we discuss the transport of Hg through the boiler and pollution control systems, the mechanisms of Hg oxidation, and the parameters controlling Hg capture by coal-derived fly ash carbons. PMID:24223466

  13. Desulphurization of coal via low temperature atmospheric alkaline oxidation.

    Science.gov (United States)

    Liu, Kaicheng; Yang, Ji; Jia, Jinping; Wang, Yaling

    2008-03-01

    Different from other options which usually required strict conditions, a method combining atmospheric oxidization and chemical cleaning with alkali solutions was employed to desulphur coals at temperature around 90 degrees C. The data show that 66% organic sulphur, 44% sulphide sulphur, and 15% pyrite sulphur were lost when the coal was treated in 0.25M NaOH at 90 degrees C, while the solution being aerated at the flow rate of 0.136m3h(-1). The rate increased to 73% for organic sulphur, 83% for sulphide sulphur and 84% for pyrite sulphur when the previous coal was further treated in acidic solution containing HCl at pH 1 for another hour. The mechanism of desulphurization was explored using inductively coupled plasma mass spectrometry, X-ray photoelectron spectroscopy and infrared. It was found out that the bond of -CS was broken by atmospheric oxygen in basic environment, leading to the lost of organic sulphur in coal. Scanning electron microscope data show that the physical structure of the coal was not adversely affected by the treatment and thermogravimetric analysis results prove that the pyrolysis behavior remained unchanged, indicating that the burning process of the coal would not be adversely affected. Unlike other oxidizing methods, this technique does not lower the heating value of the coal which was manifested by relevant data. PMID:18022211

  14. 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; Praš?áková 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 indus...

  15. Ash characterization in laboratory-scale oxy-coal combustor

    Science.gov (United States)

    Oxygen enriched coal (oxy-coal) combustion is a developing technology. During oxy-coal combustion, combustion air is separated and the coal is burned in a mixture of oxygen and recycled flue gas. The resulting effluent must be further processed before the C02 can be compressed, t...

  16. 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.

  17. 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

  18. 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.

  19. 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.)

  20. 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

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

    Science.gov (United States)

    Kronbauer, Marcio A; Izquierdo, Maria; Dai, Shifeng; Waanders, Frans B; Wagner, Nicola J; Mastalerz, Maria; Hower, James C; Oliveira, Marcos L S; Taffarel, Silvio R; Bizani, Delmar; Silva, Luis F O

    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? versus Al?O? 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. PMID:23584038

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

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Marcos L.S. [Laboratory of Environmental Researches and Nanotechnology Development, Centro Universitário La Salle, Mestrado em Avaliação de Impactos Ambientais em Mineração, Victor Barreto, 2288 Centro 92010-000, Canoas, RS (Brazil); Development Department of Touristic Opportunities, Catarinense Institute of Environmental Research and Human Development – IPADHC, Capivari de Baixo, Santa Catarina (Brazil); Marostega, Fabiane; Taffarel, Silvio R. [Laboratory of Environmental Researches and Nanotechnology Development, Centro Universitário La Salle, Mestrado em Avaliação de Impactos Ambientais em Mineração, Victor Barreto, 2288 Centro 92010-000, Canoas, RS (Brazil); Saikia, Binoy K. [Coal Chemistry Division, CSIR-North East Institute of Science and Technology, Jorhat 785006 (India); Waanders, Frans B. [School of Chemical and Minerals Engineering, North West University (Potchefstroom campus), Potchefstroom 2531 (South Africa); DaBoit, Kátia [Environmental Science and Nanotechnology Department, Institute of Environmental Research and Human Development – IPADHC, Capivari de Baixo, Santa Catarina (Brazil); Baruah, Bimala P. [Coal Chemistry Division, CSIR-North East Institute of Science and Technology, Jorhat 785006 (India); and others

    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 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.

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

    International Nuclear Information System (INIS)

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

  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. Cenosphere-load in coal-ash discharge of thermal power plant

    International Nuclear Information System (INIS)

    Cenospheres present in coal-ash are hallow solids, light in nature. During the sluicing of the ash-discharge of thermal power plant these cenospheres float on the surface, adding significantly to the load of suspended solid in the ash-pond effluents. The proportion of the cenospheres in coal-ash discharge of thermal power plant at Korba (MP) has been determined, and found to be several times higher than those reported abroad. Concentrations of a large number of toxic metals (Cu, Co, Ni, Pb, Mn, Zn, Cd, Mo, V, Cr, Sn, Be) have been determined in the cenosphere samples. The environmental aspects of the presence of cenosphere have been discussed. (author). 10 refs., 1 tab

  6. 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.

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

    Science.gov (United States)

    Komonweeraket, Kanokwan; Cetin, Bora; Benson, Craig H; Aydilek, Ahmet H; Edil, Tuncer B

    2015-04-01

    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. PMID:25555664

  8. 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...

  9. 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

  10. 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

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

    DEFF Research Database (Denmark)

    Wu, Hao; Shafique Bashir, Muhammad

    2012-01-01

    The formation of deposits during suspension-firing of wood at Avedøre Power Plant unit 2 (AVV2) was studied by using an advanced deposit probe system. The tests were conducted both with and without coal ash addition, and at two different locations with flue gas temperatures of 1250-1300 oC and 750-800 oC respectively. The deposit formation process was studied quantitatively though the mass uptake data from the load-cell of the probe, while camera pictures were used to qualitatively verify the obtained mass uptake data and to explain the deposit buildup/shedding mechanisms. The collected deposits along with the fly ash and bottom ash from the plant were characterized extensively by SEM-EDS, ICP-OES/IC and XRD. Based on the results from the present work, the deposit formation and shedding mechanisms under different operational conditions were proposed and discussed. The influence of coal ash addition on deposit formation during wood suspension-firing at AVV2 was evaluated. It was revealed that the addition of coal fly ash could significantly influence the ash deposition/shedding behaviors and the deposit properties. The effect was evident at both measurement locations. At the location with a high flue gas temperature of 1250-1300 oC, although the addition of coal fly ash increased the differential deposit formation rate (DDF-rate) and the ash deposition propensity, the deposit removal frequency were considerably increased and the major shedding mechanism was changed from soot-blowing induced shedding to natural shedding. This implied that the deposits at high temperatures were more easily removable when coal ash was added. Besides, the amount of K2SO4 in the high-temperature deposits was considerably reduced when coal ash was added, which was probably favorable in order to minimize corrosion. At the location with a low flue gas temperature of 750-800 oC, the addition of coal fly ash reduced the ash deposition propensity and caused the formed deposits being easily removable. Moreover, the KCl and KOH/K2CO3 found in the low-temperature deposits without coal ash addition disappeared when coal ash was added, which was also favorable from a corrosion point of view.

  12. 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...

  13. INTERACTION OF PLANAR AND NONPLANAR ORGANIC CONTAMINANTS WITH COAL FLY ASH: EFFECTS OF POLAR AND NONPOLAR SOLVENT SOLUTIONS

    Science.gov (United States)

    Coal fly ash has several uses but much of the material is treated as waste and disposed of in various ways including land filling. Coal fly ash also has a very high sorption capacity for a variety of anthropogenic contaminants and has been used to cleanse wastewater of such poll...

  14. 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.

  15. 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/piperazi 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.

  16. 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)

  17. The use of coal fines fly ash for the improvement of soils in hydrophobic grounds

    International Nuclear Information System (INIS)

    New NOx reducing combustion techniques result in a different physical and morphological quality of fly ash, which makes the use of fly ash less attractive for the building and road construction industries. Attention is paid to the possibility of using low-NOx fly ash for the improvement of the properties of hydrophobic agricultural land. Such an application also depends on the environmental impacts of the leaching of elements to the ground water and the accumulation of hazardous compounds in crops. A literature study of hydrophobic grounds was carried out. Also attention is paid to the legal aspects. No juridical constraints could be found in the Dutch legislation concerning the use of fly ash from coal powder, although it seems that the use of such fly ash is not in agreement with the tenor of possibly to be applied legislation. However, a small-scale investigation was carried out to gain insight into the environmental impacts. The uptake in lettuce and the leaching of the elements As, B, Mo and Se was studied by means of lysimeters. Hydrophobic soils with 5%, 10% and 15% coal fines fly ash were used. Also an experiment with the use of coal gasification slags was performed

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

    Directory of Open Access Journals (Sweden)

    Jankovi? 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, 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 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. Radiometric determination of ash content of coal with variable chemical composition

    International Nuclear Information System (INIS)

    The first part of the paper contains a review of the well knows radiometric methods of determining the ash content of coal, as well as the techniques for overcoming interferences due to variations of iron content. The advantages of the intrinsic compensation method with the use of 238Pu source, are shown. The experimental results concerning the other sources of errors, in particular grain size and water content effects, are presented. Precision, accuracy and possibilities of applying suggested method for rapid control of the ash content of coal in industry, are discussed. (author)

  20. Valorization of coal fly ash by mechano-chemical activation Part I. Enhancing adsorption capacity

    Energy Technology Data Exchange (ETDEWEB)

    Stellacci, P.; Liberti, L.; Notarnicola, M.; Bishop, P.L. [Technical University of Bari, Taranto (Italy). Dept. of Environmental Engineering & Sustainable Development

    2009-07-15

    The adsorption characteristics of coal fly ash have been enhanced by mechano-chemical activation with a high energy mono-planetary ball mill. The best performing sample for the adsorption of phenol from aqueous solution (i.e., fly ash with the higher carbon content and mechano-chemically activated for 4 h in N{sub 2} atmosphere) was compared with powdered activated carbon, yielding quite encouraging results such as favorable adsorption isotherms, improved specific adsorption capacity and very fast adsorption rate. This provides new opportunities for utilizing fly ash in environmental protection applications like the stabilization/solidification treatment of hazardous waste and contaminated soil.

  1. Computer-controlled scanning electron microscopy (CCSEM) investigation of quartz in coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Cprek, Nick; Shah, Naresh; Huggins, Frank E.; Huffman, Gerald P. [Consortium for Fossil Fuel Science, University of Kentucky, Lexington, KY 40506 (United States); Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506 (United States)

    2007-12-15

    Computer-controlled scanning electron microscopy (CCSEM) and X-ray diffraction (XRD) were used to investigate Si-rich phases in several coal fly ash (CFA) samples. The CCSEM measurements utilized both particle size distributions and a particle shape parameter, circularity, to classify the Si-rich phases in these ashes. The results indicated that the amount of free, respirable, crystalline quartz in these CFA samples was very small (< 1.0 vol.%). Neither the total quartz nor the respirable quartz determined by CCSEM showed a significant correlation with the XRD results for the bulk ash. (author)

  2. Clearance by the rat of inhaled fly ash from fluidized-bed coal combustion

    International Nuclear Information System (INIS)

    Fly ash from a fluidized-bed coal combustor was neutron-activated and administered to male Fischer 344 rats by a single nose-only inhalation exposure. The activated fly ash contained 46Sc and smaller amounts of other gamma-emitting radionuclides. Whole-body clearance of radioactivity of 127 d was described by an exponential equation, with the long-term component having a biological half-life of 78 d. High-resolution gamma spectra of the lungs was obtained with a Ge(Li) detector and the relative activities of several fly ash constituents were compared. The activities of 152Eu, 134Cs, 54Mn, and 60Co significantly decreased with time relative to those of 46Sc and 59Fe. These results indicate that the clearance of fly ash is similar to that of other relatively insoluble particles and that some elements may have been preferentially dissolved from the fly ash particles in vivo

  3. 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

  4. 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.

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

    OpenAIRE

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

    2004-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Denise Alves Fungaro

    2004-08-01

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

  7. An Evaluation on the Physical and Chemical Composition of Coal Combustion Ash and Its Co-Placement with Coal-Mine Waste Rock

    OpenAIRE

    Budi Sulistianto; Gautama, Rudy S.; Candra Nugraha; Kikuo Matsui; Hideki Shimada; Takashi Sasaoka; Kusuma, Ginting J.

    2012-01-01

    In the last few decades, the utilization of coal to generate electricity was rapidly increasing. Consequently, the production of coal combustion ash (CCA) as a by-product of coal utilization as primary energy sources was increased. The physical and geochemical characteristics of CCA were site-specific which determined by both inherent coal-source quality and combustion condition. This study was intended to characterize the physical, chemical and mineralogical properties of a coal-combustion a...

  8. 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 ication of coal ash in certain proportion is beneficial in terms of growth parameters and nutrient acquisition in guava. (author)

  9. Effects of coal fly ash on tree swallow reproduction in Watts Bar Reservoir, Tennessee.

    Science.gov (United States)

    Walls, Suzanne J; Meyer, Carolyn B; Iannuzzi, Jacqueline; Schlekat, Tamar H

    2015-01-01

    Coal-fly ash was released in unprecedented amounts (4.1?×?10(6) m(3) ) into the Emory River from the Tennessee Valley Authority Kingston Fossil Plant on Watts Bar Reservoir in Tennessee. Tree swallows were exposed to ash-related constituents at the ash release via their diet of emergent aquatic insects, whose larval forms can accumulate constituents from submerged river sediments. Reproduction of tree swallow colonies was assessed over a 2-year period by evaluating whether 1) ash constituent concentrations were elevated in egg, eggshell, and nestling tissues at colonies near ash-impacted river reaches compared to reference colonies, 2) production of fledglings per nesting female was significantly lower in ash-impacted colonies versus reference colonies, and 3) ash constituent concentrations or diet concentrations were correlated with nest productivity measures (clutch size, hatching success, and nestling survival, and fledglings produced per nest). Of the 26 ash constituents evaluated, 4 (Se, Sr, Cu, and Hg) were significantly elevated in tissues potentially from the ash, and 3 (Se, Sr, and Cu) in tissues or in swallow diet items were weakly correlated to at least one nest-productivity measure or egg weight. Tree swallow hatching success was significantly reduced by 12%, but fledgling production per nest was unaffected due to larger clutch sizes in the impacted than reference colonies. Bioconcentration from the ash to insects in the diet to tree swallow eggs appears to be low. Overall, adverse impacts of the ash on tree swallow reproduction were not observed, but monitoring is continuing to further ensure Se from the residual ash does not adversely affect tree swallow reproduction over time. Integr Environ Assess Manag 2015;11:56-66. © 2014 SETAC. PMID:25345977

  10. Nitric oxide reduction by chars derived from high ash inertinite-rich discard coals / Zebron Phiri

    OpenAIRE

    Phiri, Zebron

    2010-01-01

    An investigation was performed to determine the kinetics of nitric oxide (NO) reduction by six different chars derived from inertinite-rich low grade coals. The experimentation involving the reduction of NO was confined to conditions used in fluidised bed combustion with aspirations to provide information for the fluidised bed technology using high ash and inertinite rich South African coals. A detailed characterisation of six different chars was executed with respect to ...

  11. 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

    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 deposits at the location with high flue gas temperatures was characterized by a slow and continuous growth of deposits followed by the shedding of a large layer of deposits, while at the location with low flue gas temperature the deposit formation started with a slow build-up and the amount of deposits became almost 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, these alkali species were effectively removed both in the fly ash and in the deposits. Although the ash deposition rate at the location with high flue gas temperature was increased with coal fly ash addition, the removability of the deposits was significantly improved, resulting in a more frequent shedding of the deposits. Overall, the results from this work suggest that coal fly ash can be an effective additive to minimize the possible ash deposition and corrosion problems during suspension-firing of wood. © 2013 Elsevier Ltd. All rights reserved.

  12. 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

    2012-01-01

    This report is about full-scale probe measurements of deposit build-up and removal conducted at the Avedøreværket Unit 2, a 800 MWth suspension boiler, firing wood and natural gas with the addition of coal ash. Coal ash was used as an additive to capture potassium (K) from wood-firing. Investigations of deposit formation rate were made by use of an advanced online ash deposition/shedding probe. Quantification of ash deposition and shedding was made via deposit mass uptake signals obtained from the deposit probe. The influence of coal ash, flue gas temperature, probe surface temperature and boiler load on ash deposition propensity was investigated. Results of ash deposition propensity showed increasing trend with increasing flue gas temperature. Video monitoring revealed that the deposits formed were not sticky and could be easily removed, and even at very high flue gas temperatures (> 1350 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 the gas phase as HCl(g). Effect of boiler operational parameters on gas emissions has also been investigated.

  13. 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)

  14. Desulphurization Characteristic of Industry Alkaline Wastes during Coal Combustion

    Directory of Open Access Journals (Sweden)

    Bin Zheng

    2009-03-01

    Full Text Available 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 capture the release of sulfur at 800-1100?. Salt slurry and red mud could capture the re-lease of sulfur at first stage at 800-900?. But when the experimental temperature rises to 1000?, the sulfur capture abilities of them depress. Pore structures of waste are higher than that of limestone. This makes the sulfation reaction goes further. To sum up, wastes have better sulfur capture ability.

  15. Microspherical inorganic ion-exchangers based on cenospheres of coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    T.A. Vereshchagina; E.V. Fomenko; S.N. Vereshchagin; N.N. Shishkina; N.G. Vasilieva; E.N. Paretskov; D.M. Kruchek; T.J. Tranter; A.G. Anshits [Institute of Chemistry and Chemical Technology SB RAS, Krasnoyarsk (Russian Federation)

    2005-07-01

    Coal fly ash cenospheres are very promising for a variety of applications, such as production of porous materials, sensitisers of emulsion explosives, adsorbents, catalysts, etc. One of the interesting areas of cenosphere application is generation of microspherical ion-exchangers for immobilization of liquid radioactive waste, which are active in trapping radionuclides from radioactive solutions and, at a final step, can serve as a matrix for radionuclide disposal in the form of stable mineral-like compounds. It was demonstrated that two types of microspherical ion-exchangers, such as (I) encapsulated inorganic ion-exchangers and (ii) cenosphere-derived zeolites, could be prepared on cenospheres. It was shown that chemical modification of cenospheres by etching with mineral acids results in formation of open pores in the cenosphere wall. Depending on the nature of acid, one can obtain hollow microspheres with porous walls of different specific surface area (30-50 m{sup 2}/g for HCl etched cenospheres and 1-2 m{sup 2}/g for HF etched ones) and morphology. Cenosphere species with a macroporous permeable wall is a suitable support for encapsulation of active additives inside the perforated spheres. In this work a number of encapsulated sorbents of {sup 137}Cs{sup +}, such as ammonium molybdophosphate, copper, nickel and iron-ferrocyanides, zirconium phosphate, were obtained. Cenosphere-derived zeolites of NaP, NaX and NaA types were obtained by the hydrothermal treatment of cenospheres in the presence of alkaline solutions. Properties of the encapsulated ion-exchangers and microspherical zeolites were studied in Cs{sup +} and Sr{sup 2+} sorption from simulant solutions of different composition. Sorbents impregnated with radionuclides were shown to convert into stable crystalline compounds under thermal and thermobaric treatment. 19 refs., 5 figs., 3 tabs.

  16. 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%

  17. 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.

  18. 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 washicle 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.

  19. 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...

  20. Solvent extraction of molybdenum from biological samples and from coal fly ash for neutron activation analysis

    International Nuclear Information System (INIS)

    A technique has been developed for the determination of Mo in natural water with dithiocarbamate extraction for neutron activation analysis. This paper shows the results obtained by extending the technique to Mo determination in biological samples and in coal fly ash

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

    Scientific Electronic Library Online (English)

    Evans T., Musapatika; Maurice S., Onyango; Ochieng, Aoyi.

    2010-10-01

    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 use [...] d 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.

  2. 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)

  3. Removal of phenylacetic and phenoxyacetic acids by fly-ash-coal blend: a comparative study.

    Energy Technology Data Exchange (ETDEWEB)

    Kannan, N.; Ramasubramanian R. [Ayya Nadar Janaki Ammal College, Sivakasi (India). PG Department of Chemistry

    2001-07-01

    Studies have been made on the removal of phenylacetic and phenoxyacetic acids by adsorption on fly-ash-coal blend. The percentage removal of acids increased with increase in the content of fly ash in the blend, and increase in contact time and dose but decreased with the increase in initial concentration of acids. The adsorption data were modelled with Freundlich and Langmuir adsorption isotherms and kinetics equations and the intra-particle diffusion model. The adsorption process is found to be first order with the intra-particle diffusion as the rate limiting step. The results of the studies reveal that the fly ash-coal blend could be used as mixed low-cost adsorbent alternative to commercial activated carbon. 13 refs., 6 figs., 5 tabs.

  4. 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.

  5. Natural radioactivity in the surrounding soil and fly ash from coal fired thermal power plant

    International Nuclear Information System (INIS)

    In India about 70% of the total power generation originates from thermal power plants. The coal fired power generation results in huge amounts of fly with elevated levels of naturally occurring radionuclides. Despite the implementation of best possible mechanisms to restrict release of fly ash from the stack, a huge amount of the same gets released in the environment. Fly ash and soil from and around a 500 MW capacity coal-fired power station were measured for 238U, 226Ra, 232Th and 40K activity by an HPGe ?-ray spectrometer. The surrounding soil showed no elevated levels of the radionuclides however higher levels were observed for the same in the fly ash. (author)

  6. The Effect of Microwave Energy on Grindability of a Turkish High-Ash Coal

    OpenAIRE

    O. Y. Toraman; M.S. Del?balta

    2012-01-01

    In the present study, the effect of microwave energy on grindability of high-ash (46.39%) and sulphur (3.99%) Turkish coal has been investigated. Coal samples (-9.52+3.18 mm) was treated by microwave at a frequency of 2.45 GHz with different power levels (0.48-0.64-0.80 kW) and residence times (30-150 s.). In order to determine the crushing/grinding resistance of low ranked lignite coal samples treated by microwave oven, the Impact Strength Index (ISI) test was applied for each treat...

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

    OpenAIRE

    Jenner, H. A.

    1995-01-01

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

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

    Science.gov (United States)

    Oliveira, Marcos L S; Marostega, Fabiane; Taffarel, Silvio R; Saikia, Binoy K; Waanders, Frans B; DaBoit, Kátia; Baruah, Bimala P; Silva, Luis F O

    2014-01-15

    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. PMID:24121564

  9. Use of coal fly ash in radioactive waste disposal

    International Nuclear Information System (INIS)

    A key constituent of almost all cement-based grouts within the nuclear community is ASTM Class F fly ash. In the case of monolithic waste forms, this fly ash is routinely used for some of the same applications that proved to be beneficial in the construction industry: (1) improvement in compressive strength for mitigation of transportation accidents or overburden subsidence, (2) increased weathering resistance for improved durability after disposal, (3) increased resistance to thermal cycling for improved durability during interim storage, (4) control of fluidity during processing for process versatility and improved quality control, (5) decreased permeability and increased tortuosity for improved leach resistance, and (6) smaller increase in volume and, thus, lower final disposal costs. ASTM Class F fly ash has been the material of choice, primarily because the specifications in ASTM C 618, Standard Specifications for FLY ASH AND RAW OR CALCINED NATURAL POZZOLAN FOR USE AS A MINERAL ADMIXTURE IN PORTLAND CEMENT CONCRETE, have been sufficient for the quality control required in meeting the physical performance requirements of the grout product. However, recent calorimetric data indicate that, for some wastes, these specifications are not satisfactory for controlling total heat release. This case study discusses the results from recent preliminary calorimetry experiments and the potential impact on the use of fly ash in cement-based waste formsbased waste forms

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

    Energy Technology Data Exchange (ETDEWEB)

    Wijatno, H.

    1977-10-01

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

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

    DEFF Research Database (Denmark)

    Arvelakis, Stelios; Frandsen, Flemming

    2007-01-01

    Straw may be used today as a substitute fuel to lower the greenhouse gas emissions from traditional coalfired power plants and provide green-based electricity. It may also provide an alternative source of income to the local farmers helping the developed countries to support sustainable development. The use of straw as a co-firing feedstock in traditional coal-fired plants is associated with operational problems, such as deposition, agglomeration, and/or corrosion, mainly because of the higher amounts of alkali metals and chlorine in straw compared to coal. This may lead to unscheduled shutdowns and costly repairs, increasing the operational costs and the cost of the produced power. In this paper, the melting characteristics of several ash fractions sampled from different parts of a pilot-scale pulverized fuel (PF) boiler operating with different coal/straw mixtures is determined by measuring the ash viscosity using a high-temperature rotational viscometer. The produced data provide information on the meltingof the ash material, its flow characteristics, and the rates of crystallization and recrystallization, as a function of the temperature. This information may be used to modify the temperature profile in the different parts of the boiler to reduce the deposition of the ash material. The results show that the straw in the co-combustion mixture changes the viscosity characteristics of the produced ash fractions. The viscosity of the different ash fractions is lowered, as the percentage of straw in the cocombustion mixture increases, and leads to higher stickiness of the produced ash particles at lower temperatures.

  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. Design of a leaching test framework for coal fly ash accounting for environmental conditions.

    Science.gov (United States)

    Zandi, Mohammad; Russell, Nigel V

    2007-08-01

    Fly ash from coal combustion contains trace elements which, on disposal or utilisation, may leach out, and therefore be a potential environmental hazard. Environmental conditions have a great impact on the mobility of fly ash constituents as well as the physical and chemical properties of the fly ash. Existing standard leaching methods have been shown to be inadequate by not representing possible disposal or utilisation scenarios. These tests are often criticised on the grounds that the results estimated are not reliable as they are not able to be extrapolated to the application scenario. In order to simulate leaching behaviour of fly ash in different environmental conditions and to reduce deviation between measurements in the fields and the laboratories, it is vital to study sensitivity of the fly ash constituents of interest to major factors controlling leachability. pH, liquid-to-solid ratio, leaching time, leachant type and redox potential are parameters affecting stability of elements in the fly ash. Sensitivity of trace elements to pH and liquid to solid ratio (as two major overriding factors) has been examined. Elements have been classified on the basis of their leaching behaviour under different conditions. Results from this study have been used to identify leaching mechanisms. Also the fly ash has been examined under different standard batch leaching tests in order to evaluate and to compare these tests. A Leaching Test Framework has been devised for assessing the stability of trace elements from fly ashes in different environments. This Framework assists in designing more realistic batch leaching tests appropriate to field conditions and can support the development of regulations and protocols for the management and disposal of coal combustion by-products or other solid wastes of environmental concern. PMID:17171257

  14. Coal fly ash utilization: Low temperature sintering of wall tiles

    International Nuclear Information System (INIS)

    We present here a study of the sintering of fly ash and its mixture with low alkali pyrophyllite in the presence of sodium hexa meta phosphate (SHMP), a complex activator of sintering, for the purpose of wall tile manufacturing. The sintering of fly ash with SHMP in the temperature range 925-1050 deg. C produces tiles with low impact strength; however, the incremental addition of low alkali pyrophyllite improves impact strength. The impact strength of composites with ?40% (w/w) pyrophyllite in the fly ash-pyrophyllite mix satisfies the acceptable limit (19.6 J/m) set by the Indian Standards Institute for wall tiles. Increasing the pyrophyllite content results in an increase in the apparent density of tiles, while shrinkage and water absorption decrease. The strength of fly ash tiles is attributed to the formation of a silicophosphate phase; in pyrophyllite rich tiles, it is attributed to the formation of a tridymite-structured T-AlPO4 phase. Scanning electron micrographs show that the reinforcing rod shaped T-AlPO4 crystals become more prominent as the pyrophyllite content increases in the sintered tiles

  15. 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.

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

    Science.gov (United States)

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

    2009-07-15

    This study deals with the use of fly ash as a starting material for geopolymeric matrices. The leachable concentrations of geopolymers were compared with those of the starting fly ash to evaluate the retention of potentially harmful elements within the geopolymer matrix. Geopolymer matrices give rise to a leaching scenario characterised by a highly alkaline environment, which inhibits the leaching of heavy metals but may enhance the mobilization of certain oxyanionic species. Thus, fly ash-based geopolymers were found to immobilize a number of trace pollutants such as Be, Bi, Cd, Co, Cr, Cu, Nb, Ni, Pb, Sn, Th, U, Y, Zr and rare earth elements. However, the leachable levels of elements occurring in their oxyanionic form such as As, B, Mo, Se, V and W were increased after geopolymerization. This suggests that an optimal dosage, synthesis and curing conditions are essential in order to obtain a long-term stable final product that ensures an efficient physical encapsulation. PMID:19118943

  17. 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 ?Ci/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 ?Ci/cm3. It is pointed out that if a 25% porosity were used, the Radon concentration will be an order of magnitude higher. (U.K.)

  18. 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

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

    OpenAIRE

    Hower, James C.; Senior, Constance L.; Suuberg, Eric M.; Hurt, Robert H.; 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, ...

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

    Directory of Open Access Journals (Sweden)

    Goñi, S.

    2010-06-01

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

    En este trabajo se presenta el papel que juega la temperatura durante el tratamiento hidrotermal en medio alcalino para convertir una ceniza volante de bajo contenido en cal (clase F, según la norma ASTM en zeolita. Durante este tratamiento a la temperatura de 100ºC se forma Zeolita Na-P1 tipo gismondina (Na6Al6Si10O32.12H2O; al elevar la temperatura a 200ºC, dicha zeolita se transforma en zeolita Analcima C (Na(Si2AlO6H2O y en fase sodalita (1.08 Na2O.Al2O3.1.68SiO2.1.8H2O junto con trazas de tobermorita-11Å (Ca5(OH2Si6O16.4H2O. A esta temperatura y en estas condiciones se ha conseguido un 100% de reacción. Un estudio equivalente se ha llevado a cabo empleando agua como medio de referencia. La conversión de ceniza volante en zeolita se ha caracterizado mediante técnicas, como difracción de Rayos X (DRX, espectroscopia infrarroja por transformada de Fourier (FTIR y análisis térmico (TG/ATD; así mismo los cambios en el área superficial se han llevado a cabo mediante la técnica BET-N2.

  1. Recycling of waste coal fly ash: synthesis of zeolite-like minerals from residue yielded by extraction of aluminum ions

    Energy Technology Data Exchange (ETDEWEB)

    M.S. Ryu; H.G. Sin; S.H. Park; S.Y. Yoon; R. Stevens; H.C. Park [Pusan National University, Pusan (Republic of Korea). School of Materials Science and Engineering

    2006-07-01

    The conversion of residue, by extraction processing of aluminum ions from coal fly ash to zeolitic materials by hydrothermal treatment in the presence of NaOH solution, was investigated and the resulting material characterized.

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

    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 gamma-rays and 0.511 MeV annihilation and Compton scattered gamma-rays measured. Earlier laboratory tests on 50 kg samples of high ash coals gave errors of 0.46 to 1.3 wt% ash. A plant test to assess the pair production gauge for direct on-line conveyor belt analysis is described. This test was carried out on a recirculating coal loop at a Broken Hill Pty. Ltd. coal washery pilot plant. Samples were measured on-belt as a function of sample depth, compaction, moisture and particle size. The technique was found to provide accurate measurements of the ash content of coal in a constant geometry. It can be used to determine ash content of coal of thickness 60-220 mm on a conveyor belt by an additional measurement of the weight per unit area of coal on the belt by ?-ray transmission

  3. Fly ash from fluidized bed coal combustion as complex cement addition

    Energy Technology Data Exchange (ETDEWEB)

    Roszczynialski, W.; Nocun-Wczelik, W.; Gawlicki, M. [Univ. of Mining and Metallurgy, Krakow (Poland). Faculty of Materials Science and Ceramics

    2001-07-01

    The cement industry is actively involved in finding ways to use waste products in the manufacturing of cement. In particular, it is involved in the use of secondary fuels and raw materials, used in components of kiln raw meal or cement admixtures. Most of the by-products used in cement production originate from the power industry, particularly those plants that use black coal and generate fly ashes, active pozzolanic admixtures. This paper discussed the feasibility of using by-product gypsum generated in fluidized bed combustion installations for use in concrete. Fluidized bed fly ashes have different chemical composition and physical properties than conventional fly ash and constitute a valuable active pozzolanic and sulphate-set controlling admixture to cement. Their use would reduce energy consumption significantly and would also contribute to a reduction in greenhouse gas emissions into the atmosphere. The use of fluidized bed fly ash in cement would also reduce the consumption of portland cement clinker and gypsum. This paper presented the laboratory scale experiment in terms of calorimetric studies of cement hydration kinetics, standard properties of cements, and industrial scale production of cements admixtures with fluidized bed combustion fly ash. Anhydrite II is present in fluidized bed fly ashes and is considered to be the best set controlling agent which prevents false setting and lumps. 7 refs., 6 tabs., 5 figs.

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

    International Nuclear Information System (INIS)

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

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

    OpenAIRE

    Izquierdo, M.; Tye, A. M.; Chenery, S. R.

    2013-01-01

    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 th...

  6. 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)

  7. 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 ?m) 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

  8. 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)

  9. 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)

  10. Composition, morphology, properties of coal fly ash microspheres and their application for conditioning liquid radioactive waste

    Energy Technology Data Exchange (ETDEWEB)

    Anshits, N.N. [Institute of Chemistry and Chemical Technology, SB RAS (ICCT SB RAS), Krasnoyarsk (Russian Federation)]. E-mail: anshits@icct.ru; Salanov, A.N.; Vereshchagina, T.A.; Kruchek, D.M.; Bajukov, O.A.; Tretyakov, A.A.; Revenko, Yu.A.; Anshits, A.G

    2006-07-01

    Using methods of the Moessbauer spectroscopy, scanning electron microscopy, and thermodynamic analysis of phase formation in silicate multi-component melts, the detailed study of composition, morphology, and properties of fly ash microspheres resulting from combustion of three coals (Irsha-Borodinskii, Kuznetskii and Ekibastuzskii) was carried out. About 60 microspherical products with an iron content of 2-94 wt.% Fe{sub 2}O{sub 3} were obtained. The ranges of microsphere composition, suitable for liquid radioactive waste solidification in the forms of iron phosphate (36-94 wt.% Fe{sub 2}O{sub 3}) and aluminosilicate (2-20 wt.% Fe{sub 2}O{sub 3}) ceramics were determined. The possibility of producing porous materials and specific microspherical sorbents, based on coal fly ash cenospheres and their application for mobilisation of liquid radioactive waste solidification was demonstrated. (author)

  11. Composition, morphology, properties of coal fly ash microspheres and their application for conditioning liquid radioactive waste

    International Nuclear Information System (INIS)

    Using methods of the Moessbauer spectroscopy, scanning electron microscopy, and thermodynamic analysis of phase formation in silicate multi-component melts, the detailed study of composition, morphology, and properties of fly ash microspheres resulting from combustion of three coals (Irsha-Borodinskii, Kuznetskii and Ekibastuzskii) was carried out. About 60 microspherical products with an iron content of 2-94 wt.% Fe2O3 were obtained. The ranges of microsphere composition, suitable for liquid radioactive waste solidification in the forms of iron phosphate (36-94 wt.% Fe2O3) and aluminosilicate (2-20 wt.% Fe2O3) ceramics were determined. The possibility of producing porous materials and specific microspherical sorbents, based on coal fly ash cenospheres and their application for mobilisation of liquid radioactive waste solidification was demonstrated. (author)

  12. Ultrasonic coal-wash for de-ashing and de-sulfurization. Experimental investigation and mechanistic modeling

    Energy Technology Data Exchange (ETDEWEB)

    Ambedkar, B. [Indian Institute of Technology Madras, Chennai (India). Dept. of Chemical Engineering

    2012-07-01

    This study focuses on the physical aspects of ultrasonic de-ashing and de-sulfurization, such as cavitation, streaming and their combined effects. Ambedkar Balraj proposes an ultrasound-assisted coal particle breakage mechanism and explores aqueous and solvent-based ultrasonic techniques for de-ashing and de-sulfurization. Ambedkar designs a Taguchi L-27 fractional-factorial matrix to assess the individual effects of key process variables. In this volume he also describes process optimization and scale-up strategies. The author provides a mechanism-based model for ultrasonic reagent-based coal de-sulfurization, proposes a flow diagram for ultrasonic methods of high-throughput coal-wash and discusses the benefits of ultrasonic coal-wash. Coal will continue to be a major fuel source for the foreseeable future and this study helps improve its use by minimising ash and sulfur impurities.

  13. Valorization of coal fly ash by mechano-chemical activation Part II. Enhancing pozzolanic reactivity

    Energy Technology Data Exchange (ETDEWEB)

    Stellacci, P.; Liberti, L.; Notarnicola, M.; Bishop, P.L. [Technical University of Bari, Taranto (Italy). Dept. of Environmental Engineering & Sustainable Development

    2009-07-15

    The pozzolanic and adsorptive characteristics of coal fly ash have been enhanced by mechano-chemical activation in order to evaluate their potential utilization in the stabilization/solidification treatment of hazardous wastes. To that aim a soil artificially contaminated by large amounts of Phenol and Pb underwent that treatment, wherein increasing amounts of powder activated carbon and Portland cement were substituted by mechano-chemically activated fly ash. Under the experimental conditions investigated, very encouraging results, in terms of contaminants leaching and mechanical properties of the stabilized/solidified matrix, were obtained when up to 100% of the powder activated carbon and up to 50% of the Portland cement were substituted by mechano-chemically activated fly ash, thus opening improved possibilities for using this latter in environmental applications.

  14. Coal Fly Ash Impairs Airway Antimicrobial Peptides and Increases Bacterial Growth

    OpenAIRE

    Borcherding, Jennifer A.; Chen, Haihan; Caraballo, Juan C.; Baltrusaitis, Jonas; Pezzulo, Alejandro A.; Zabner, Joseph; Grassian, Vicki H.; Comellas, Alejandro P.

    2013-01-01

    Air pollution is a risk factor for respiratory infections, and one of its main components is particulate matter (PM), which is comprised of a number of particles that contain iron, such as coal fly ash (CFA). Since free iron concentrations are extremely low in airway surface liquid (ASL), we hypothesize that CFA impairs antimicrobial peptides (AMP) function and can be a source of iron to bacteria. We tested this hypothesis in vivo by instilling mice with Pseudomonas aeruginosa (PA01) and CFA ...

  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. 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.

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

    Science.gov (United States)

    Sun, Yong; Parikh, Vinay; Zhang, Lian

    2012-03-30

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

  18. 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

  19. 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

  20. 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)

  1. Commercial fertilizer made from coal ash; Sekitanbai wo riyoshita futsu hiryo ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Aoki, M. [Central Research Inst. of Electric Power Industry, Abiko, Chiba (Japan). Abiko Research Lab.

    1994-08-01

    The outlines of the potassium silicate fertilizer and compound fertilizer, which are commercial fertilizers produced utilizing coal ash, are introduced. The role of fertilizer is to replenish the short supply of the nutrient elements which can not be fulfilled by nature, and the requirements for the fertilizer are different from the essential elements of plants. The kinds and required amounts of fertilizer elements are different according to such environmental conditions as the kind of crops, target yield of crops, and conditions of soil. Micronutrients other than boron and manganese are not approved to be used as the main components for commercial fertilizers. Addition of copper, zinc, molybdenum, and iron are approved only for foliar application fertilizers. There are chemical and physical methods for producing delayed release fertilizers. Nitrogen fertilizer, potassium fertilizer, dried algae, coal ash and phosphoric acid liquid are mixed, granulated and dried to produce coal ash compound fertilizers. It is made clear that the effect of this fertilizer is slow, and can be a natural resources-saving and environmental protecting value added compound fertilizer. 1 tab.

  2. 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.

  3. Metal leaching from experimental coal fly-ash oyster cultch

    Energy Technology Data Exchange (ETDEWEB)

    Homziak, J.; Bennett, L.; Simon, P.; Herring, R. (Mississippi State University, MS (USA). Coastal Research and Extension Center)

    1993-08-01

    Because oysters accumulate metals far in excess of ambient concentrations potential leaching and bioaccumulation of metals may be important public health concerns where ash-cement aggregates are being considered for oyster cultivation. This study examined the potential for metal release from an ash-cement aggregate proposed for use in oyster reef construction in Mississippi coastal waters. Seven acid-washed aquaria were each filled with 77L of artificial seawater. Five randomly selected aquaria each received 8.6 L of aggregate pellets. Samples were taken from each aquarium one hour after the start of the experiment and at 10 day intervals on six subsequent sampling dates. The samples were analysed for arsenic, cadmium, chromium, copper, iron, lead, manganese, mercury, nickel, selenium and zinc. Cadmium, iron and mercury were essentially not detected in the treatment aquaria. Except for chromium, the mean concentrations of metals in the treatment samples were generally less than 10 ppb. An overall comparison of the concentrations of 8 metals among all aquaria and sampling dates detected significant differences in the concentration of chromium (p[lt]0.001), manganese (p[lt]0.05) and selenium (p[lt]0.001). Treatment aquaria had significantly greater concentrations of chromium and selenium than did either control (nonparametric multiple comparison, p[lt]0.05). Most of the chromium found in the treatment aquaria was the hexavalent form (means range from 0.052 to 1.328 ppm). Treatment hexavalent chromium concentrations increased over time. 14 refs., 1 fig., 2 tabs.

  4. DISPOSAL, RECYCLE, AND UTILIZATION OF MODIFIED FLY ASH FROM HYDRATED LIME INJECTION INTO COAL-FIRED UTILITY BOILERS

    Science.gov (United States)

    The paper gives results of an assessment of the disposal, utilization, and recycle os a modified fly ash from the injection of hydrated lime into a coal-fired utility boiler. The process, developed as a low-cost alternative for achieving moderate degrees of SO2 control at coal-fi...

  5. Fast neutron activation analysis of bulk coal samples for alumina, silica and ash

    International Nuclear Information System (INIS)

    The fast neutron activation technique was applied to bulk samples (approximately 11 kg) of Australian black coal. The determination of alumina is based on the reaction 27Al(n,p)27Mg by counting the 0.844-MeV peak (tsub(1/2) = 9.4 min). Silica is determined by means of the reaction 28Si(n,p)28Al; the 1.78-MeV peak (tsub(1/2) = 2.3 min) is counted and a correction for the interference from alumina is applied. The ash content is based on the correlation between ash and the sum of alumina and silica. The accuracies (1 SD) for the determination of alumina, silica and ash were 0.52% Al2O3, 0.79% SiO2 and 1.02% ash, respectively. The ash, alumina and silica contents of the samples were in the ranges 8.8-37.5%, 1.3-10.3% and 6.4-22%, respectively. (Auth.)

  6. 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.

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

    Science.gov (United States)

    Ivankovi?, Tomislav; Hrenovi?, Jasna; Itskos, Grigorios; Koukouzas, Nikolaos; Kova?evi?, Davor; Milenkovi?, Jelena

    2014-12-01

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

  8. 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 fct 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)

  9. Ash transformation in suspension fired boilers co-firing coal and straw : Final report, PSO-Eltra 4766

    DEFF Research Database (Denmark)

    Zheng, Yuanjing; Jensen, Peter Arendt

    2009-01-01

    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 bituminous coal. The laboratory experiments indicated which mineral types and local conditions that provide the most efficient binding of potassium to species with a high melting point, and where a simultaneous release of chlorine as gaseous HCl takes place.

  10. The influence of minerals content and petrographic composition on the gasification of inertinite rich high ash coal / A.F. Koekemoer.

    OpenAIRE

    Koekemoer, Andrei Frederik

    2010-01-01

    Coal particles with different densities have different mineral and maceral compositions and this affects the gasification reaction rates, especially in coals with high ash contents. This study involved the characterization of six Highveld coals (coals A – F) as well as a coal blend (coal G) consisting of several of these single- source coals in terms of chemical, maceral, mineral and structural properties. This initial characterization was supported by the evaluation of the pyrolysis gas c...

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

    Science.gov (United States)

    Cowan, Ellen A; Seramur, Keith C; Hageman, Steven J

    2013-03-01

    An estimated 229,000 m(3) 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 (?(LF)) and percent frequency dependent susceptibility (?(FD)%) to be used to discriminate between coal fly ash and sediments native to the watershed. Riverbed samples with ?(LF) greater than 3.0 × 10(-6) m(3)/kg, have greater than 15% ash measured by optical point counting. ?(LF) 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 ?(LF). Measurement of ?(LF) is inexpensive, non-destructive, and a reliable analytical tool for monitoring the fate of coal ash in this fluvial environment. PMID:23266939

  12. 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

    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 growth of deposits followed by the shedding of a large layer of deposits, while the deposit formation at the low-temperature location showed a slow initial build-up and a stable mass of deposits after approximately 1-5 h. The deposits collected during pulverized wood combustion contained a considerable amount of K2SO4, KCl, and KOH/K2CO3. With the addition of coal fly ash (~4 times of the mass flow of wood ash) to the boiler, these alkali species were effectively removed both in the fly ash and in the deposits, and a morefrequent 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-fired boiler.

  13. Removal of heavy metals from wastewater using functionalized coal fly ashes

    International Nuclear Information System (INIS)

    Complete text of publication follows. Among inorganic pollutants, heavy metal ions are very toxic and carcinogenic in nature. The presence of heavy metals in the aquatic environment has been of the greatest concern because of their toxicity even at very low concentrations. Therefore, the removal of the toxic metal ions prior to supplying water for drinking, bathing, etc is very important. Nonetheless, the removal of the toxic metal ions from water is a very difficult task due to the high cost of treatment methods. Adsorption is by far the most versatile and widely used method for this purpose. In this study, attempts have been made to develop a low-cost adsorbent using coal fly ashes, a waste byproduct of the coal fire industry, for the removal of arsenic, aluminium, cadmium, zinc, copper, iron, lead, manganese and nickel from wastewater. After applying a washing step to the coal fly ashes, functionalized fly ash surfaces were accomplished by using several organic compounds. The effect of several parameters (contact time, temperature, time that the ashes remain functionalized, concentration of the heavy metals, solution pH) on the adsorption process was stated. Several equilibrium and kinetics treatments were also carried out, also resulting that the adsorption process was found to be exothermic in nature. Retention studies were characterised by SEM/ED-XRS, FT-IR, Raman spectrometry and electrothermal atomic absorption spectrometry (ETAAS). The optimised retention sysmetry (ETAAS). The optimised retention system was applied to develop an analytical procedure for the retention of low concentrations of lead in wastewater and determination by ETAAS.

  14. Measurement of radon exhalation rate and estimation of radiation doses in coal and fly ash samples from a thermal power plant

    International Nuclear Information System (INIS)

    Combustion of coal and the subsequent emissions to the atmosphere cause the re-distribution of radioactive trace elements like uranium, the source of radon gas in the environment. In the present study radon exhalation rates in coal and fly ash samples from Kolaghat Thermal Power Plant (W.B.) have been measured by 'Can technique' using LR-115 type II detectors. Radon exhalation rate in fly ash samples is found to be higher than in coal and combustion of coal enhances the radionuclide concentration in fly ash. Radiation doses from the fly ash samples have been estimated from radon exhalation rate and radionuclide concentrations. (author)

  15. 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.

  16. Coal fly ash and lime addition enhances the rate and efficiency of decomposition of food waste during composting

    Energy Technology Data Exchange (ETDEWEB)

    Wong, J.W.C.; Fung, S.O.; Selvam, A. [Hong Kong Baptist University, Hong Kong (China). Dept. of Biology

    2009-07-15

    To evaluate the use of coal fly ash (CFA) on the decomposition efficiency of food waste, synthetic food waste was mixed with lime at 1.5% and 3% (equivalent to 0.94% and 1.88% CaCO{sub 3}, respectively), CFA at 5%, 10% and 15% with lime so as to achieve CaCO{sub 3} equivalent of 1.88% and composted for 42 days in a thermophilic 201 composter with two replicates each. Alkaline materials at 1.88% CaCO{sub 3} equivalent successfully buffered the pH during the composting and enhanced the decomposition efficiency. When these buffering was achieved with CFA + lime, the composting period could be shortened to similar to 28 days compared with similar to 42 days in 3% lime. Organic decomposition in terms of CO{sub 2} loss, carbon turnover and nitrogen transformation were significantly higher for treatments with 1.88% CaCO{sub 3} equivalent. Nutrient transformations and compost maturity parameters indicated that addition of CFA (5-10%) with lime at 1.88% CaCO{sub 3} equivalent enhances the decomposition efficiency and shortens the composting period by 35%.

  17. 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.

  18. Effects of inhaled coal fly ash on lung biochemistry and function in guinea pigs

    International Nuclear Information System (INIS)

    The ultrafine fraction of particles produced during the combustion of coal are the most difficult to remove with control devices and are retained longest in the atmosphere. Combustion of a high-sulfur coal, such as Illinois No. 6, produces a significant quantity of sulfuric acid, most of which is absorbed to the surface of those particles smaller than 1 ?m in diameter. Particles smaller than 0.05 ?m in diameter, moreover, consist largely of sulfuric acid; since these particles penetrate to the deepest regions of the lung, exposure to coal fly ash can result in the administration of large doses of acid to the alveolar tissues. Using a combustion system that generates coal fly ash similar to that collected in flue gas, guinea pigs were exposed for 2 h to aerosols produced from Illinois No. 6 (mean aerodynamic diameter 0.2 ?m) at concentrations of 5 and 20 mg/m3. The animals were lavaged at 24 h post-exposure and levels of dehydrogenase (LDH), ?-glucuronidase (?-GC), and protein were compared to those of control animals. After 24 h, no changes in levels of LDH and ?-GC were seen in the lavage fluid from both high-dose and low-dose animals. Slight, but statistically significant elevations in protein concentration were measured in the high-dose exposure group. The total cell number in the lavage fluid was also found exposure group. The total cell number in the lavage fluid was also found to be exchanged following both exposures. It was previously found thaposures. It was previously found that exposure to 5 mg/M3 of Illinois No. 6 fly ash results in immediate reductions in pulmonary diffusing capacity (DLco), total lung capacity (TLC), and vital capacity, and that both DLco and TLC values are not completely restored to normal 96 h post-exposure. These results suggest that the alterations in pulmonary function resulting from exposure to acidic coal fly ash are not accompanied by major inflammatory changes in lavage fluid

  19. 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.

  20. 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 coals 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.

  1. Utilization of ash and gypsum produced by coal burning power plants

    International Nuclear Information System (INIS)

    By-products of coal burning in power plants, mainly fly ash and gypsum, have a number of possible applications in the building industry and in road construction. However, due to the very large production, complete utilization of the by-products is not always possible. Considering that the production of by-products will increase in the future, it is important to explore new useful applications of fly ash and gypsum in order to limit the amounts disposed of in landfills. The use of fly ash and gypsum to make blocks utilized in construction of artificial reefs is an interesting concept. Experiments carried out in USA and Japan have given promising results. ISMES has started the investigation of alternative procedures to produce blocks suitable for artificial reef construction. Initial tests on leaching materials formed by codl processing of fly ash and gypsum have given negative results but further work applying greater pressure and with the addition of small amounts of binder should result in a successful product. 7 refs., 1 tab

  2. 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

  3. Mechanical properties of high dense coal fly-ash bulk materials by plasma spark sintering (SPS)

    Energy Technology Data Exchange (ETDEWEB)

    Kaneko, G.; Hasezaki, K.; Nakashita, A.; Kakuda, H. [Shimane University, Shimane (Japan). Dept. of Material Science

    2008-10-15

    Coal fly-ash bulk materials were prepared by spark plasma sintering (SPS). The as-received coal fly ash produced by Misumi Power Station (The Chugoku Electric Power Co. Inc.), had an average particle size of 19 mm and contained about 2% carbon from unburned coal. The sintering temperature was 1273 K for 10 min. The mass density of the sintered compact was 2.4 x 103 kg/m{sup 3}. After three-point flexural testing of the compact, the average flexural strength and Young's modulus were 25.6 MPa and 23.0 GPa, respectively. From the flexural strength, the Weibull modulus was found to be m = 6.13, indicating that the compact was a typical ceramics. Fractographic examination indicated that in all specimens the fracture origin was located on the bottom surface and was not an intrinsic flaw. Vickers indentation test showed that the fracture toughness was 0.61 MPa.m{sup 0.5} and the calculated critical flaw size c{sub 0}, was 0.18 mm. This c{sub 0} value was larger than that of the voids and the unburned carbon at the fracture surface. It is noteworthy that the mechanical strength of the sintered compact was not affected by the voids and unburned carbon.

  4. 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.

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

    International Nuclear Information System (INIS)

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

  6. 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

  7. 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

  8. 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.

  9. 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)

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

    Scientific Electronic Library Online (English)

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

    2004-08-01

    Full Text Available [...] Abstract in english 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.

  11. 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.

  12. 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)

  13. 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 m) 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).

  14. 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.

  15. 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

  16. Measurement of radon activity, exhalation rate and radiation dose in fly ash and coal samples from NTPC, Badarpur, Delhi, India

    International Nuclear Information System (INIS)

    In the present study radon activities and exhalation rates from fly ash and coal samples from NTPC (National Thermal Power Corporation) situated at Badarpur, Delhi, India, have been measured. 'Sealed Can Technique' using LR-115 type II track detectors was employed. In fly ash samples, radon activity has been found to vary from 400.0 ± 34.7 to 483.9 ± 38.1Bqm-3 with an average value of 447.1 ± 36.6 Bqm-3 and in coal samples, radon activity has been found to vary from 504.0 ± 39.0 to 932.1 ± 52.9 Bqm-3 with an average value of 687.2 ± 45.2 Bqm-3. Radon exhalation rate from coal is found to be higher than radon exhalation rate from its ash products, whereas the opposite is expected. Indoor inhalation exposure (radon) effective dose has also been estimated. (author)

  17. Prediction of compressive strength of cement mortars with fly ash and activated coal gangue

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Shuangxi; Chen Yimin; Zhou Shuangxi [China Building Materials Academy, Beijing (China)

    2006-07-01

    The pozzolanic activity of coal gangue, which is calcining at 500 to 1,000{sup o} differs distinctly. The simplex - centroid design with upper and lower bounds of component proportion is adopted to study the compressive strength of mortars made with ternary blends of cement. activated coal gangue and fly ash. Based on the results of a minimum of seven design points, three special cubic polynomial models are used to establish the strength predicating equations at different ages for mortars. Five experimental checkpoints were also designed to verify the precision of the equations. The most frequent errors of the predicted values are within 3%. A simple and practical way is provided for determining the optimal proportion of two admixtures when they are used in concrete. 7 refs.

  18. 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

  19. Use of the flying ashes of the coal in the synthesis of zeolitic material with interchange properties of ammonium ion

    International Nuclear Information System (INIS)

    In this research W and F zeolites are synthesized from analytical reagents and from coal fly ash as a source of aluminum and silicon. The primary goal with the synthesis of these materials is to show the possibility of their economic production and their potential application in ammonium removal from aquaculture water and wastewater. The results show that zeolites W and F can be obtained readily from the coal fly ashes almost with the same synthesis parameters as when pure analytical reagents are used for the same purpose. Their ammonium ion exchange capacity indicates that zeolites from both types of sources, behave similarly

  20. Coal fly ash effluent affects the distributions of Brachionus calyciflorus sibling species.

    Science.gov (United States)

    Zhang, Gen; Xi, Yi-Long; Xue, Ying-Hao; Xiang, Xian-Ling; Wen, Xin-Li

    2015-02-01

    Fly ash, a coal combustion residue of thermal power plants and a source of multiple pollutants, has been recognized as an environmental hazard all over the world. Although it is known that fly ash effluent affects density, diversity and distribution of rotifers in drainage systems and receiving water bodies, the effect of fly ash effluent on the distributions of highly similar rotifer species remains unknown. In this study, the mtDNA COI genes of 90 individuals in Brachionus calyciflorus complex from Lake Hui (as a fly ash discharge water pond) and other two neighboring lakes (Lake Fengming and Lake Tingtang) were sequenced and analyzed, and the responses in selected life table demographic parameters (life expectancy at hatching, net reproductive rate, intrinsic rate of population increase and proportion of sexual offspring) of different rotifer populations to fly ash effluent were investigated. Overall, 72 mtDNA haplotypes were defined, and were split into two clades by the phylogenetic trees. The divergence of COI gene sequences between the two clades ranged from 11.8% to17.8%, indicating the occurrence of two sibling species (sibling species I and sibling species II). Sibling species I distributed in all the three lakes, showing strong capabilities for dispersal and colonization, which were supported by its higher level of gene flow (2.60-4.04) between the populations from Lake Hui and each of the other two lakes, longer life expectancy at hatching (101.6-148.2 h), and higher net reproductive rate (4.4-16.4 offspring/female) and intrinsic rate of population increase (0.60-0.98/d) when cultured in aerated tap water and fly ash effluent. Sibling species II distributed in both Lake Tingtang and Lake Fengming, showing that its dispersal existed between the two lakes. Considering that the distance between Lake Hui and Lake Fengming is shorter than that between Lake Tingtang and Lake Fengming, sibling species II is able to disperse at least from Lake Fengming to Lake Hui. The restricted distribution of sibling species II in Lake Hui might be attributed to its lower intrinsic rate of population increase (0.34-0.39/d) when cultured in aerated tap water and fiy ash effluent, which might be further lowered by the lower algal food level and quality in Lake Hui. PMID:25463854

  1. Possibilities of utilization of fly ash from the black coal Power Engineering of the U. S. Steel Košice

    OpenAIRE

    Františka Michalíková; Vladimír Jacko

    2005-01-01

    The paper presents modes of a direct utilization of the fly ash by-product of the combustion of black power coal in the slag - bottom boilers of the Division Plant Power Engineering ( DP PE ) of the U. S. Steel Košice ( next USSK ). The properties of fly ash limit its use in metallurgy and foundry industry. The fly ash is directly utilizable in the metallurgical industry as a component of powder cover mixtures and insulation inserts, heat insulation parts and exothermical mixtures. The most ...

  2. 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.

  3. 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 ?m, 18–20 ?m and 15–17 ?m 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.

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

    International Nuclear Information System (INIS)

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

  5. 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

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

    Science.gov (United States)

    González, Aixa; Navia, Rodrigo; Moreno, Natalia

    2009-12-01

    Coal fly ashes (CFA) are generated in large amounts worldwide. Current combustion technologies allow the burning of fuels with high sulfur content such as petroleum coke, generating non-CFA, such as petroleum coke fly ash (PCFA), mainly from fluidized bed combustion processes. The disposal of CFA and PCFA fly ashes can have severe impacts in the environment such as a potential groundwater contamination by the leaching of heavy metals and/or particulate matter emissions; making it necessary to treat or reuse them. At present CFA are utilized in several applications fields such as cement and concrete production, agriculture and soil stabilization. However, their reuse is restricted by the quality parameters of the end-product or requirements defined by the production process. Therefore, secondary material markets can use a limited amount of CFA, which implies the necessity of new markets for the unused CFA. Some potential future utilization options reviewed herein are zeolite synthesis and valuable metals extraction. In comparison to CFA, PCFA are characterized by a high Ca content, suggesting a possible use as neutralizers of acid wastewaters from mining operations, opening a new potential application area for PCFA that could solve contamination problems in emergent and mining countries such as Chile. However, this potential application may be limited by PCFA heavy metals leaching, mainly V and Ni, which are present in PCFA in high concentrations. PMID:19423583

  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. 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 ...

  9. In situ borehole determination of ash content of coal using gamma-gamma and neutron-gamma techniques

    International Nuclear Information System (INIS)

    During the past decade, borehole logging technology based on nuclear geophysics has found wide application in the Australian coal-mining industry. In response to the need for further improved accuracy in coal ash measurements, the Commonwealth Scientific and Industrial Research Organization, Division of Mineral Physics, has developed two new alternative techniques, which are both spectrometric. The spectrometric gamma-gamma technique is based on the existence of a simple correlation between the ash content and the equivalent atomic number and density of coal. The technique is spectrometric in that it records and uses the count rates in several windows of the backscatter spectrum. These count rates and their selected ratios describe the changes in spectral shape which are due to ash content variations. The spectrometric neutron-gamma method is suitable where the probe responses are required for specific elemental contents. Consequently, the method tolerates larger variations in ash composition for accurate measurement than does the gamma-gamma method. Both methods have been tested at several coal deposits in New South Wales and Queensland. For both techniques, RMS deviations between nuclear assay and chemical analysis are typically 2% ash in the range 5 to 40% ash. Both techniques are currently undergoing commercial development under the name of SIROLOG. The SIROLOG technology is designed to accommodate logging speeds up to 4m.min-1. However, the gamma-gammamin-1. However, the gamma-gamma probe uses gamma-ray sources of strength two orders of magnitude smaller than that of sources used in commercial probes. The logging system provides information on ash content in 5 cm intervals if required, although the vertical resolution of the probes is 30-35 cm. (author)

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

    Science.gov (United States)

    Smolka-Danielowska, Danuta

    2010-11-01

    The subject of the study covered volatile ashes created during hard coal burning process in ash furnaces, in power plants operating in the Upper Silesian Industrial Region, Southern Poland. Coal-fired power plants are furnished with dust extracting devices, electro precipitators, with 99-99.6% combustion gas extracting efficiency. Activity concentrations ofTh-232, Ra-226, K-40, Ac-228, U-235 and U-238 were measured with gamma-ray spectrometer. Concentrations of selected rare soil elements (La, Ce, Nd, Sm, Y, Gd, Th, U) were analysed by means of instrumental neutron activation analysis (INAA). Mineral phases of individual ash particles were identified with the use of scanning electron microscope equipped with EDS attachment. Laser granulometric analyses were executed with the use of Analyssette analyser. The activity of the investigated fly-ash samples is several times higher than that of the bituminous coal samples; in the coal, the activities are: 226Ra - 85.4 Bq kg(-1), 40 K-689 Bq kg(-1), 232Th - 100.8 Bq kg(-1), 235U-13.5 Bq kg(-1), 238U-50 Bq kg(-1) and 228Ac - 82.4 Bq kg(-1). PMID:20713303

  11. Determination of sulfur in coal and ash slurry by high-resolution continuum source electrothermal molecular absorption spectrometry

    International Nuclear Information System (INIS)

    We propose a procedure for the determination of sulfur in coal slurries by high resolution continuum source electrothermal molecular absorption spectrometry. The slurry, whose concentration is 1 mg mL?1, was prepared by mixing 50 mg of the sample with 5% v/v nitric acid and 0.04% m/v Triton X-100 and was homogenized manually. It sustained good stability. The determination was performed via CS molecular absorption at 257.592 nm, and the optimized vaporization temperature was 2500 °C. The accuracy of the method was ensured by analysis of certified reference materials SRM 1632b (trace elements in coal) and SRM 1633b (coal fly ash) from the National Institute of Standards and Technology, using external calibration with aqueous standards prepared in the same medium and used as slurry. We achieved good agreement with the certified reference materials within 95% confidence interval, LOD of 0.01% w/w, and RSD of 6%, which confirms the potential of the proposed method. - Highlights: • HR-CS ET MAS as a technique to determine sulfur in coal and ash • Utilization of (coal and coal fly ash) slurry as a sample preparation • Simple and fast method, which uses external calibration with aqueous standards without chemical modifier

  12. Determination of sulfur in coal and ash slurry by high-resolution continuum source electrothermal molecular absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Nakadi, Flávio V.; Rosa, Lilian R.; Veiga, Márcia A.M.S. da, E-mail: mamsveiga@ffclrp.usp.br

    2013-10-01

    We propose a procedure for the determination of sulfur in coal slurries by high resolution continuum source electrothermal molecular absorption spectrometry. The slurry, whose concentration is 1 mg mL{sup ?1}, was prepared by mixing 50 mg of the sample with 5% v/v nitric acid and 0.04% m/v Triton X-100 and was homogenized manually. It sustained good stability. The determination was performed via CS molecular absorption at 257.592 nm, and the optimized vaporization temperature was 2500 °C. The accuracy of the method was ensured by analysis of certified reference materials SRM 1632b (trace elements in coal) and SRM 1633b (coal fly ash) from the National Institute of Standards and Technology, using external calibration with aqueous standards prepared in the same medium and used as slurry. We achieved good agreement with the certified reference materials within 95% confidence interval, LOD of 0.01% w/w, and RSD of 6%, which confirms the potential of the proposed method. - Highlights: • HR-CS ET MAS as a technique to determine sulfur in coal and ash • Utilization of (coal and coal fly ash) slurry as a sample preparation • Simple and fast method, which uses external calibration with aqueous standards without chemical modifier.

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

    Science.gov (United States)

    Papandreou, A; Stournaras, C J; Panias, D

    2007-09-30

    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 3-8mm, 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. PMID:17416461

  14. 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.

  15. Determination of uranium and thorium in coal ash and power station precipitator ash and in bauxite and red sludge by activation analysis with epithermal neutrons

    International Nuclear Information System (INIS)

    The activation with epithermal neutrons is used for the quantitative determination of uranium and thorium. The method does not require any special irradiation and measuring installations. In brown coal ashes 0,4 to 6 ppm uranium and 4 to 18 ppm thorium, in bauxite and red sludge 11 and 27 ppm uranium, respectively, and 47 and 134 ppm thorium, respectively, could be reliably determined. (orig.)

  16. 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 ?g 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 concranging from 3 to 5% depend upon the concentration of uranium. (author)

  17. MCM-41 SYNTHESIZED FROM COAL FLY ASH AS A CATALYST IN THE PRODUCTION OF BIODIESEL USING PALM OIL.

    Directory of Open Access Journals (Sweden)

    M.R. DESHPANDE

    2013-05-01

    Full Text Available Coal fly ash was used to synthesize MCM-41 by alkali fusion followed by hydro- thermal treatment and was characterized using various techniques viz. XRD, SEM, FTIR, BET method for surface area measurement etc. The synthesis conditions were optimized to obtain highly crystalline MCM-41 with utmost BETsurface area 1102m2/g with high purity. The crystalline nature of the prepared MCM-41 was found to change with fusion temperature and a maximum value was obtained at 5500 C. The cost of synthesized MCM-41 was projected to be very few as compared to that of commercial MCM-41.This work presents the results of transesterification reaction using palm oil as feedstock with methanol and coal fly ash (CFA catalyst derived to produce methyl esters (biodiesel.The fly ash based catalyst was prepared using the wet impregnation procedure with different loadings of potassium. This was characterized by powder X-ray diffraction (XRD, SEM etc

  18. 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....

  19. Remoção de íons Zn2+, Cd2+ e Pb2+ de soluções aquosas usando compósito magnético de zeólita de cinzas de carvão Removal of Zn2+, Cd2+ e Pb2+ ions from aqueous solutions by magnetic composite of zeolite from coal ashes

    OpenAIRE

    Denise Alves Fungaro; Mitiko Yamaura; José Eduardo Alves Graciano

    2010-01-01

    For this study, magnetic composite of zeolite-magnetite was prepared by mixing magnetite nanoparticles suspension with synthetic zeolite. The nanoparticles in suspension were synthesized by precipitating iron ions in a NaOH solution. The zeolite was synthesized from coal fly ash by alkaline hydrothermal treatment. The magnetic composite was characterized by XDR, SEM, magnetization measurements, IR, and BET surface area. Batch tests were carried out to investigate the adsorption of metal ions ...

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

    International Nuclear Information System (INIS)

    IAEA-RCA/RAS on NCS project have been operating from 2001 brought a new conception and approach about application of nuclear and nucleonic techniques in member states. Through 4 cycle of projects (RAS/8/089, RAS/8/094, RAS/8/099 and RAS/8/107), by a step-by-sep technical transfer, higher level on later phase, this technical transfer way has corrected disadvantages and opened new applications, helps the member states from passive receiving to active joining into higher level of technical development for particular application, in each member state. A regional demonstration centre has been set up in Hanoi - Vietnam, to train personnel from around the RCA region in the use of this instrumentation. The centre in Hanoi has been set a coal ash determination instruments using back-scattered gamma and coal ash logging instrument using PGNAA methods. In 2008, through project RAS/8/107, IAEA has aided a neutron generator and Vietnam had a responsibility to develop Ash content Bulk Analysis by PGNAA. Prompt gamma neutron activation analysis technique (PGNAA) is one among advanced techniques over the world. Advantages of this technique are fast analysis, good accuracy, sample process is not required, no influences of measurement environment and analysis of almost elements in the periodic table. Based on this issue, project Research and development of PGNAA coal ash analyser using neutron generator, carried out since 9/2009, finished in 9/2011 have achieved the first achievements 2011 have achieved the first achievements in fast coal ash determination. Developed Ash content Bulk Analysis by PGNAA has following technical parameters: result of coal ash determined has absolute error less than 1%; uses Cf-252 neutron source with neutron flux of 0.85 x 106 n/s; uses BGO detector with size of 51 x 51mm, 2000 channels of ADC; analysis time is 600 s; mass of analysed coal sample is 700 kg; PC connected via USB interface on Window XP; neutron dose and gamma dose around the instruments are less than allowed doses in IAEA safety standards (allowed dose for radiation personnel is 5 ?Sv/h). The project has created out following procedures: procedure of coal ash analysis, procedure for calibration of ash content, procedure for processing of standard samples; user manual is also written. This Ash content Bulk Analysis by PGNAA system is using in laboratory, and its is needed to study and to improve more, to analyse not only ash content of coal buts also element contents and other parameters, such as moisture, volatiles content and so on of the coal; it is also needed to open new capability of measurements for other object (cement, soil), and changing the design to be a field an in-situ instrument. It is emphasized to improve this system and technique, step-by-step, to make it suitable for strict requirements of industry in industrialize-modernize process of Vietnam. By revealed advantages of PGNAA technique, this kind of system should be developed and improved to catch the fast development of automation in industry. (author)

  1. On-line determination of the ash content of coal using a SIROASH gauge based on the transmission of low and high energy #betta#-rays

    International Nuclear Information System (INIS)

    A gauge based on measurements of the transmission through coal of low and high energy #betta#-rays has been developed for the on-line determination of the ash content. The SIROASH (CSIRO ASH) gauge has been tested on the final product line of a coal washery at Gregory, Queensland, Australia. The r.m.s. difference between ash determined on-line and ash determined by chemical assay of coal sampled from the conveyor was 0.45 wt%. Chemical assay and sampling errors, estimated to be between 0.2 and 0.3 wt% ash, contribute to this difference. The SIROASH gauge measures coal directly on the conveyor, and can be calibrated using standard samples by moving it beyond the edge of the conveyor belt. (author)

  2. Enhanced abatement of HCl by a nobel coal ash/calcium hydroxide hybrid sorbent

    Energy Technology Data Exchange (ETDEWEB)

    Naoki Tanahashi; Yoshimasa Akatsuka; Yoshihiro Kojima; Daisuke Hirabayashi; Hitoki Matsuda [Chubu Electric Power Co., Nagoya (Japan). Energy Applications Research and Development Center

    2003-07-01

    A novel calcium-based sorbent was prepared by hydration treatment of coal burnt ash mixed with Ca(OH){sub 2}. The mixing molar ratio of Ca(OH){sub 2} to coal burnt ash was adjusted to 1.5. To evaluate the HCl sorption performance of the prepared calcium-based sorbent, the same HCl sorption test was conducted by employing slaked lime and calcined dolomite. The experiment was conducted by the use of a lab-scale packed bed reactor (20mm inner diameter), in which the sample pellets size of 3mmc x 2mm were packed in a quartz tube in 15mm height, by introducing a mixed gas of HCl (10,000ppm)-N{sub 2} to the reactor at a constant flow rate of 500ml/min, in the temperature range of 823K and 1123K. The HCl sorption capacity of each sorbent was compared by using the dimensionless breakthrough time, t/{tau}. The HCl sorption capacity of the proposed Ca-based sorbent was 1.8 times larger than those of slaked lime and calcined dolomite at 823K. On the other hand, the HCl sorption capacity of the proposed sorbent was smallest among the three sorbents at 1173K. From a SEM-EDX observation, it was considered that the HCl could penetrate effectively to the inside of the sorbent, because the main components of SiO{sub 2} and Al{sub 2}O{sub 3} in coal ash contributed to keeping the pores even after the HCl sorption at 823K. Three low temperature eutectic mixtures of grossular (Ca{sub 3}Al{sub 2}(SiO{sub 4}){sub 2}(OH){sub 4}), mayenite (Ca{sub 12}Al{sub 4}O{sub 33}) and calcium silicate chloride (Ca{sub 3}SiO{sub 4}C{sub l2}) were detected by the XRD results of the sorbent subjected to the HCl sorption at 1123K. 9 refs., 7 figs., 4 tabs.

  3. 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 (?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-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.

  4. 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.

  5. 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)

  6. 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 connemm 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

  7. Analytical applications of atomic spectroscopy, with particular reference to inductively coupled plasma emission analysis of coal and fly ash

    International Nuclear Information System (INIS)

    This thesis outlines the analytical applications of atomic emission and absorption spectroscopy to a variety of materials. Special attention was directed to the analysis of coal and coal ashes. A simple slurry sampling technique was developed and used to determine V, Ni, Co, Mo and Mn in the National Bureau of Standards Standard Reference Materials (NBS-SRM) coals 1632a and 1635 by furnace atomic absorption spectroscopy (FAAS). Coal and fly ash were analysed by inductively coupled plasma atomic emission spectroscopy (ICP-AES). The determination of B, Be, Li, C, K and other trace elements by ICP-AES was investigated. Analytical methods were developed for the analysis of coal, fly ash and water samples. Fusion with sodium carbonate and a digestion bomb dissolution method were compared for the determination of boron in a South African boron-rich mineral (Kornerupine). Eight elements were determined in 10 industrial water samples from a power plant. Ca, Mg, Si and B were determined by ICP-AES and V, Ni, Co and Mo by FAAS. Various problems encountered during the course of the work and interferences in ICP-AES analysis are discussed. Some recommendations concerning method development and routine analysis by this technique are suggested

  8. An experimental comparison of the ash formed from coals containing pyrite and siderite mineral in oxidizing and reducing conditions

    Energy Technology Data Exchange (ETDEWEB)

    McLennan, A.R.; Bryant, G.W.; Bailey, C.W.; Stanmore, B.R.; Wall, T.F. [University of Newcastle, Callaghan, NSW (Australia). Cooperative Research Centre for Black Coal Utilization, Dept. of Chemical Engineering

    2000-04-01

    Four coals containing iron mineral pyrite (FeS{sub 2}) and siderite (FeCO{sub 3}) were combusted in a laboratory drop tube furnace at temperatures of 1300, 1450 and 1600{degree}C under oxidizing and reducing conditions. Results for the behavior of pyrite mineral were in agreement with the established literature. The behavior of siderite mineral was determined and comparisons made. Coals containing pyrite minerals were determined to have potential to produce ash deposition and slagging at lower temperatures than coals containing siderite mineral. Reducing conditions were determined to lower the temperature at which ash deposition and slagging may occur for coals containing iron minerals compared to oxidizing conditions. With respect to ash deposition and slagging, it was determined that the iron levels in a coal are not definitive, but rather the iron mineral type (pyrite or siderite), mineral association (included or excluded), degree of association of included minerals, and the type of included alumino-silicate minerals have important roles. 39 refs., 5 figs., 5 tabs.

  9. 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)

  10. 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

  11. 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)

  12. Prevention of the third phase formation during coal ash pulp extraction by silicon acid congelation method

    International Nuclear Information System (INIS)

    Several principles of silicon acid congelation in the process of sulphuric acid leaching are studies. In order to solve the problem of the third phase formation and of high organic loss during coal ash pulp extraction, silicon acid congelation method is presented. The main advantage of this method is the controll of the pH in leaching process by using the relationship between silicon acid congelation and pH to make the silicon acid in the leached pulp to be congelated and sedimentated. And the oleophilic solid particles in the pulp can be changed into hydrophilic and carried down by the cogelation and sedimcntation. In this way the third phase can be prevented and the loss of organic can be decreased

  13. Non-hydrothermal synthesis of mesoporous materials using sodium silicate from coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Halina, M.; Ramesh, S.; Yarmo, M.A.; Kamarudin, R.A. [University of Tenaga Nas, Selangor (Malaysia). College of Engineering

    2007-02-15

    Siliceous mesoporous materials with pores of ordered 2-D hexagonal structure were successfully prepared without hydrothermal treatment from condensation-polymerization of various concentration of quaternary ammonium salt as structure directing agents and silica precursor from the supernatant of coal fly ash (CFA) in the presence of catalyst. The synthesized materials had high surface area of ca. 740 m{sup 2} g{sup -1} and pore volume of ca. 0.42 mL g{sup -1}. The synthesized material exhibited a narrow size pore distribution and the mean pore diameter as measured by Dollimore-Heal method was about 2.3 nm. The formation of ammonium salt that act as precipitant during the synthesis enable the hydrolysis and co-condensation of the sodium silicate at room temperature.

  14. Determination of trace elements in fly coal ash (ENO, EOP and ECH reference materials)

    International Nuclear Information System (INIS)

    Instrumental neutron activation analysis has been used to determine the concentrations of 32 elements in three reference materials, for an intercomparison organized by the Institute of Radioecology and Applied Nuclear Techniques, Koshice, Czechoslovakia, with the participation of 34 laboratories from 11 countries. Fly-ash materials from coal fired power plants were analyzed. The concentration of Ba, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, La, Lu, Nd, Rb, Sb, Sc, Sm, Sr, Ta, Tb, Th, U, Yb, Zn, Zr was determined after a long irradiation (50 hours) of the samples in a thermal neutron flux of 1,1x1011 n/cm2.s. The samples and Soil-5, SL-1, GSP-1 as standards were measured 2-5 hours after decay time of 10-30 days. The results obtained for ENO, EOP and ECH are in generally good agreement with the certified values

  15. Mineralogical features of size and density fractions in Sasol coal gasification ash, South Africa and potential by-products

    Energy Technology Data Exchange (ETDEWEB)

    R.H. Matjie; C. Van Alphen [Sasol Technology (Pty) Ltd., Sasolburg (South Africa)

    2008-07-15

    Bulk gasification ash (a mixture of coarse and fine ash particles), a by-product of coal gasification, is formed at elevated temperatures and pressures by the interaction of included minerals present in the coal and 'stone'. From the detailed mineralogical and chemical analyses of the pulverised screened size fractions and one density float fraction ({lt}1.9 g/cm{sup 3}) a number of potential viable by-products were identified. Screening and density separation produced a high ash, low volatile carbon-rich by-product, which is potentially suitable as an energy source for the cement industry. In addition, this carbon-rich product has included devolatilised kaolinite and quartz that are a source of Al{sub 2}O{sub 3} and SiO{sub 2}. This product could potentially replace the amount of clay required in the cement process. This high ash carbon product is not suitable as a reductant in the metallurgical industry. The -38 + 20 {mu}m ash size fraction is characterised by a comparatively high proportion of aluminosilicate (transformed product of kaolinite) and Ca-oxide/CaMg-oxide (transformed product of calcite/dolomite). These phases will enhance the pozzolanic reactivity of this ash size fraction and provide material suitable for the cement/concrete industry. The coarse ash size fractions are used as aggregate in road construction and in the manufacture of bricks. If economically and technically feasible, anorthite in the coarse ash size fractions could be beneficiated and used in a refractory. 12 refs., 9 figs., 2 tabs.

  16. 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.

  17. Alkaline hydrothermal conversion of fly ash precipitates into zeolites 3: The removal of mercury and lead ions from wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Vernon Somerset; Leslie Petrik; Emmanuel Iwuoha [University of the Western Cape, Bellville (South Africa). Sensor Research Laboratory, Department of Chemistry

    2008-04-15

    In this paper, the utilisation of zeolites synthesised from fly ash (FA) and related co-disposal filtrates as low-cost adsorbent material were investigated. When raw FA and co-disposal filtrates were subjected to alkaline hydrothermal zeolite synthesis, the zeolites faujasite, sodalite and zeolite A were formed. The synthesised zeolites were explored to establish its ability to remove lead and mercury ions from aqueous solution in batch experiments, to which various dosages of the synthesised zeolites were added. The test results indicated that when increasing synthesised zeolite dosages of 5-20 g/L were added to the acid mine drainage (AMD) wastewater, the concentrations of lead and mercury in the wastewater were reduced accordingly. The lead concentrations were reduced from 3.23 to 0.38 and 0.17 {mu}g/kg, respectively, at an average pH of 4.5, after the addition of raw FA zeolite and co-disposal filtrate zeolite to the AMD wastewater. On the other hand, the mercury concentration was reduced from 0.47 to 0.17 {mu}g/kg at pH=4.5 when increasing amounts of co-disposal filtrate zeolite were added to the wastewater. The experimental results had shown that the zeolites synthesised from the co-disposal filtrates were effective in reducing the lead and mercury concentrations in the AMD wastewater by 95% and 30%, respectively.

  18. 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.)

  19. 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.

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

    International Nuclear Information System (INIS)

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

  1. 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

  2. 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.

  3. Design variables of pilot scale electrostatic separator for removing unburned carbon from coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.K.; Lee, H.D. [Korean Electric Power Research Institution, Taejon (Republic of Korea)

    2009-07-01

    A pilot scale beneficiation system for removing unburned carbon from coal fly ash was developed and tested using a continuous triboelectrostatic separator composed of two vertical electrodes and an ejector tribocharger. Tests were conducted to evaluate the charge density and the separation efficiency at various operating conditions. With a stainless steel tribocharger, the optimum conditions for achieving maximum charge density were as follows: air flow rate, 3.4 m{sup 3}/min; feed rate, <300 kg/h; relative humidity, <30%. Under these optimum conditions, clean ash with an LOI (loss on ignition) of less than 4.5% could be recovered (yield: >70%). The electrostatic separator was operated under the following conditions: width of the diffuser slit, 4 mm; air velocity at the diffuser outlet, 16.7 m/s; distance between the diffuser slit and the splitter, 15 cm. The optimum feed rate was found to be 830 kg/h per square meters of the electrode surface area, which can be used as the scale-up factor for the electroseparator.

  4. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Liu, W.S.; Hou, H.B.; Zhang, C.H.; Zhang, D.J. [Wuhan University, Wuhan (China). School of Resource & Environmental Science

    2009-05-15

    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.

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

    International Nuclear Information System (INIS)

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

  7. Radon exhalation rate in coal and fly ash from thermal power plants, environmental implications

    International Nuclear Information System (INIS)

    An attempt has been made to assess the radiological impact due to fly ash generated from two Thermal Power Plants in the state of Uttar Pradesh situated at Kasimpur (KTPP) and Dadri (NTPC) by measuring radon activity and radon exhalation rate. Radon exhalation rate from coal has been compared with that of fly ash. Samples obtained from thermal power plants were dried and sieved through a 100- mesh sieve. 'Can' technique using Solid State Nuclear Track Detectors (SSNTDs) has been used for radon exhalation measurements. From the track density of the exposed track detectors radon activity and radon exhalation rate were obtained. In coal samples from Kasimpur (KTPP) radon activity is found to vary from 1985.7 to 4071.4 Bq m-3 with an average value of 3183.3 Bq m-3, whereas radon exhalation rate varies from 713.9 to 1464.8 mBq m-2h-1 with an average value of 1165.1 mBq m-2h-1. In fly ash samples, radon activity is found to vary from 1502.9 to 4102.9 Bqm-3 with an average value of 3019.3 Bqm-3, whereas the radon exhalation rate varies from 540.3 to 1475.1 mBq m-2h-l with an average value of 1085.5 mBq m-2h-1. The effective dose equivalent varies from 63.7 to 173. 9 iSvY-1. In case of NTPC, Dadri radon activities are found to vary from 2211.4 to 3778.6 Bq m-3 with an average value of 2745 Bq m-3, whereas radon exf 2745 Bq m-3, whereas radon exhalation rate varies from 646.1 to 1358.5 mBq m-2h-1 with an average value of 987.0 mBq m-2h-1. The effective dose equivalent varies from 76.2 to 160.2 iSv Y-1. (author)

  8. 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.

  9. Evaluation of exposure reducing measures on parameters of genetic risk in a population occupationally exposed to coal fly ash.

    Science.gov (United States)

    Stierum, R H; Hageman, G J; Welle, I J; Albering, H J; Schreurs, J G; Kleinjans, J C

    1993-12-01

    In a previous study we found increased SCE frequencies in peripheral blood lymphocytes (PBLs) of workers occupationally exposed in a coal fly ash processing industry, as compared to a non-exposed control population. Shortly after this study, measures were taken in this plant to reduce fly ash levels. The objective of the present study, conducted 2 years later in the same plants, was to evaluate the effect of these measures with respect to genotoxic risk. A group of 18 male workers of the coal fly ash processing industry agreed to participate in the study. The control population consisted of 18 male workers from a flour processing industry, who were matched for age and smoking behavior. In contrast to our previous study, no increased SCE frequencies were found in PBLs of workers potentially exposed to coal fly ash when compared to the control group (mean SCEs: 6.4 +/- 1.2 and 7.0 +/- 0.9, respectively). In addition, no differences were observed between the exposed and control groups for frequencies of gene mutations at the hypoxanthine guanine phosphoribosyltransferase (hprt) locus in PBLs, for micronucleus frequencies using the cytokinesis block method, or for urinary mutagen excretion measured with Salmonella typhimurium tester strains TA98 and TA97 with and without metabolic activation. In smokers, however, SCE frequencies in PBLs were significantly increased in comparison to non-smokers (7.1 +/- 1.1 vs. 6.1 +/- 0.5; P processing plant appear to have been sufficient, since an effect of exposure to coal fly ash on parameters of genetic risk was not found any longer. PMID:7504197

  10. 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

  11. Assessment of ecotoxicological risks of element leaching from pulverized coal ashes

    International Nuclear Information System (INIS)

    The main objective of this study was to assess the effects on representative organisms, after exposure to pulverized fuel ashes (PFA) or leachates of PFA. The studies dealt primarily with toxic effects and focused on the impact of PFA on single species and groups of related species including their acute effects, bioconcentration and ultimate body burden. Emphasis was placed on reproductive effects in this study. Crawling behaviour of mussels was also studied to reflection to the physical differences of PFA from other substrates. A newly developed device was therefore used for valve movement monitoring. A phytomonitoring system with duckweed was developed for assessing effects on yield, using image processing. The results are presented in three parts according to the environmental compartments concerned i.e. marine, freshwater and terrestrial. In Part 1, marine studies with benthic invertebrates were carried out in model ecosystems with different compositions of PFA and Waddensea sediment. In Part 2, the freshwater studies were carried out in flow chambers using the painters mussel Unio pictorum. Besides behavioural studies with PFA specific research was carried out with selenium on body burden and effects on reproduction. Selenium is a prominent constituent of PFA. In Part 3 research is described on the monitoring of leachates of PFA with duckweed. A separate chapter deals with growth, mortality and accumulation in plants and worms exposed to coal gasification slag. fworms exposed to coal gasification slag. figs., tabs., refs

  12. 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 zeoluitable for synthesizing high quality zeolite, and the products are suitable for heavy metal removal from wastewater

  13. 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 pthat 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

  14. Evaluation of occupational radiological exposures associated with fly ash from French coal power plants

    International Nuclear Information System (INIS)

    The French Ministry of Health is preparing a series of decrees for transposing into French regulation Title VII of the European Council Directive 96/29/Euratom concerning in particular the work activities where natural radioactive substances are handled and used, but not for their radioactive, fertile or fissile properties. Coal power stations belong to a list of industrial sectors potentially concerned by this transposition and the decrees' calendar of preparation includes a consultation period allowing the collection of information about the possible dosimetric impacts on various population groups of these industrial sectors. At the request of the two French operators of coal power stations, Electricite de France (EDF) and the National Company of Electricity and Thermics (LA SNET), CEPN has evaluated occupational radiological exposures resulting from industrial activities that bring into play fly ash produced by the French coal power stations. In a first step, the various stages of the French fly ash cycle were studied, namely production, handling and transport, storage, and recycling (mainly in building materials and road works). In a second step, reference groups of workers likely to receive significant doses were identified. Finally, a series of exposure scenarios, aiming to be both conservative and realistic, were described on the basis of realistic exposure data (when available) together with generic values and simplifying assumptions. In the absence of dosimeting assumptions. In the absence of dosimetric measurements, individual exposures were evaluated using appropriate models for external irradiation, dust and radon inhalation, ingestion and transfer in the biosphere. Estimated annual individual doses range from fractions to hundreds of microsieverts per year and maximum doses are associated with situations (tailings works, road construction) where external contribution is slightly dominating. Sensitivity analyses were performed to evaluate the impact on dose estimates of possible variations of the calculation parameters. This study should provide both industrial and regulatory bodies with a methodological approach enabling to pinpoint situations in the French context that may be calling for particular attention in terms of radiation protection. This paper summarizes the assessment methodology as well as the characteristics and associated individual doses of the most important scenarios. (author)

  15. Composition and sintering characteristics of ashes from co-firing of coal and biomass in a laboratory-scale drop tube furnace

    International Nuclear Information System (INIS)

    In this study ash Ts (sintering temperature) is proposed as an index to evaluate deposition propensity during coal and biomass co-firing. The experiments were carried out in a drop-tube furnace and the resulting ash samples were collected. Ts of the ash samples was measured with a pressure-drop sintering device. The chemical compositions and mineral phase characteristics of the ashes were also analyzed using ICP (inductively coupled plasma), SEM (scanning electron microscope) and XRD (X-ray diffraction), respectively. Ts decreased with increasing the mass ratio of biomass to coal with a non-linear relationship. The straw showed a more significant effect on the ash sintering temperature than the sawdust. The limitation of contents in the fuel blends should be 15% and 50% for straw and sawdust, respectively. SEM analysis indicated that biomass promoted ash deposition by accelerating the formation of neck between ash particles. Transformations of the mineral matter to lower sintering temperatures during co-firing had occurred. - Highlights: • We studied the impact of biomass types and content on ash sintering from co-firing. • The relationship between ash sintering temperature and B:A ratio was established. • The introduction of biomass promoted the ash sintering behavior. • We studied the law for transformation of elemental compositions during co-firing. • Coal–biomass blends should be limited to 15% for straw and 50% for sawdust

  16. Direct identification of hazardous elements in ultra-fine and nanominerals from coal fly ash produced during diesel co-firing.

    Science.gov (United States)

    Martinello, Kátia; Oliveira, Marcos L S; Molossi, Fernando A; Ramos, Claudete G; Teixeira, Elba C; Kautzmann, Rubens M; Silva, Luis F O

    2014-02-01

    This study has provided an initial assessment of the environmental impacts and potential health effects associated with coal fly ash produced during diesel co-firing. Many hazardous elements that are typically detected by multifaceted chemical characterization by XRD, petrology, FE-SEM/EDS, and HR-TEM/SEAD/FFT/EDS in ultra-fine compounds and nanominerals from the co-fired coal fly ashes (CFAs). It provided an in-depth understanding of coal ash produced during diesel co-firing. Several of the neoformed ultra-fine compounds and nano-minerals found in the coal ashes are the same as those commonly associated with oxidation/transformation of aluminosilicates, carbonates, sulphides and phosphates. PMID:24157478

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

    Science.gov (United States)

    Zheng, Lei; Wang, Wei; Shi, Yunchun

    2010-04-01

    The present research explored the application of geopolymerization for the immobilization and solidification of municipal solid waste incineration (MSWI) fly ash. The influence of alkaline activator dosage and Si/Al molar ratio on the compressive strength and microstructure of MSWI fly ash-based geopolymer was investigated. A geopolymer with the highest strength was identified to occur at an intermediate alkaline activator dosage and Si/Al ratio, and the optimal Na/MSWI fly ash and Si/Al molar ratio was close to 2.8 mol kg(-1) and 2.0, respectively. IR spectra showed that higher alkaline activator dosage enhanced the structural disruption of the original aluminosilicate phases and a higher degree of polymerization of the geopolymer networks. At low Si/Al ratio, there was an increasing number of tetrahedral Al incorporating into the silicate backbone. As the Na/MSWI fly ash ratio increased, the microstructure changed from containing large macropores to more mesopores and micropores, indicating that more geopolymers are formed. Furthermore, the pore volume distribution of geopolymers was observed to shift to larger pores as the Si/Al ratio increased, which suggests that the soluble silicon content serves to reduce the amount of geopolymers. Heavy metal leaching was successfully elucidated using the first-order reaction/reaction-diffusion model. Combining the results from the microstructure of samples with the kinetic analysis, the immobilization mechanism of Cr, Cu, and Zn was inferred in this study. The methodologies described could provide a powerful set of tools for the systematic evaluation of element release from geopolymers. PMID:20304461

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

    International Nuclear Information System (INIS)

    The utilization of fly ashes in Slovakia is lower than in other countries and dumping of fly ashes prevails. The dumping changes chemical and phase composition of fly ashes and so it decreases possibilities for their utilization. Fly ashes are mainly used in building industry, where the content of loss on ignition (LOI) is limited due to standards. Black coal fly ashes produced in Slovakia have a high content of loss on ignition - more than 20 % - so they straight utilization in building industry is not possible. The current possibility for their utilization is in geopolymer synthesis. Products with 28-day compression strength of 35.7 MPa and 180-day compression strength of 55.0 MPa were obtained by alkali activation of fly ashes with 23.25 % LOI with 8 wt % Na2O and their next hardening in temperature of 80 grad C during 6 hours. Products have a great frost-resistance and aggressive environments resistance (NaCl a H2SO4 solutions). (authors)

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

    Directory of Open Access Journals (Sweden)

    Michalíková Františka

    2010-11-01

    Full Text Available 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 industry is not possible. The current possibility fortheir utilization is in geopolymer synthesis. Products with 28-day compression strength of 35.7 MPa and 180-day compression strengthof 55.0 MPa were obtained by alkali activation of fly ashes with 23.25 % LOI with 8 wt% Na2O and their next hardening in temperatureof 80 °C during 6 hours. Products have a great frost-resistance and aggressive environments resistance (NaCl a H2SO4 solutions.

  20. Determinação de enxofre em amostras vegetais por oxidação via seca em meio alcalino com detecção espectrofométrica / Espectrofotometric determination of sulfur in plants using dry ash oxidation and alkaline oxidizers

    Scientific Electronic Library Online (English)

    Alexssandra Luiza Rodrigues Molina, Rossete; Josiane Meire Tolotti, Carneiro; Hugo Henrique, Batagello; Juliana Graciela Giovannini, Oliveira; José Albertino, Bendassolli.

    Full Text Available [...] Abstract in english The sulphur take an essential role in plants and it is one of the main nutrients in several metabolic processes. The dry ash oxidation, using alkaline oxidizers agent, is the simplest and most economical form for the oxidation of Organic S to sulfate in plants. The objective of this work is to propo [...] se a method for sulfur determination in plants samples using dry ash oxidation and agent oxidizers alkaline. The quantification of S-SO4(2-) in samples was accomplished by turbidimetric method. The results demonstrated that the proposed method for oxidation alkaline was appropriate.

  1. Determinação de enxofre em amostras vegetais por oxidação via seca em meio alcalino com detecção espectrofométrica Espectrofotometric determination of sulfur in plants using dry ash oxidation and alkaline oxidizers

    Directory of Open Access Journals (Sweden)

    Alexssandra Luiza Rodrigues Molina Rossete

    2011-01-01

    Full Text Available The sulphur take an essential role in plants and it is one of the main nutrients in several metabolic processes. The dry ash oxidation, using alkaline oxidizers agent, is the simplest and most economical form for the oxidation of Organic S to sulfate in plants. The objective of this work is to propose a method for sulfur determination in plants samples using dry ash oxidation and agent oxidizers alkaline. The quantification of S-SO4(2- in samples was accomplished by turbidimetric method. The results demonstrated that the proposed method for oxidation alkaline was appropriate.

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

    International Nuclear Information System (INIS)

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

  3. Long-term trial of a dual energy ?-ray transmission gauge determining the ash content of washed coking coal on a conveyor belt

    International Nuclear Information System (INIS)

    A dual energy ?-ray transmission technique has been used to determine the ash content of coal on a coking coal product conveyor. The gauge was operated on-line for 5 months in 1984 and 8 months in 1985. The r.m.s. difference between gauge ash and chemical assay of the 2 h composite samples for 1984 was 0.31 wt% ash for ash in the range 5.5-9 wt%, and for 1985, 0.40 wt% ash for ash in the range 5-10 wt%. The r.m.s. difference of 0.40 wt% ash for 1985 is known to include gauge errors of about 0.2 wt% ash due to ash composition changes and at least 0.14 wt% ash due to instability in measurement of count rate, and a 0.18 wt% ash error due to subsampling and chemical assay errors. The experience from this trial has led to a number of improvements in calculation methods, and to better methods of calibration of the gauge for on-line use. (author)

  4. Current state of art and perspectives for development of nuclear methods for measuring ash content of coal

    Energy Technology Data Exchange (ETDEWEB)

    Pak, Yu.N.; Starchik, L.P.

    1980-04-01

    Discusses measurement methods based on gamma-absorption or dispersion. Elimination of interfering factors such as iron content, coal thickness and moisture by selecting optimal radiation intensity is examined and a formula is given for mean quadratic error. Several Soviet and foreign measuring instruments are reviewed: Mintek, GIZ, VSKZ, Cendre-X, ZAR-2, AERE, Sorteks, Begar, RAM-1-M, EhAZ, MNG-201, IMPW-1. Future development points towards more extensive use of neutron methods, which achieve high accuracy, and may be used to determine other coal properties apart from ash content. (30 refs.) (In Russian)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-04-15

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

  6. Possibilities of utilization of fly ash from the black coal Power Engineering of the U. S. Steel Košice

    Directory of Open Access Journals (Sweden)

    Františka Michalíková

    2005-11-01

    Full Text Available The paper presents modes of a direct utilization of the fly ash by-product of the combustion of black power coal in the slag - bottom boilers of the Division Plant Power Engineering ( DP PE of the U. S. Steel Košice ( next USSK . The properties of fly ash limit its use in metallurgy and foundry industry. The fly ash is directly utilizable in the metallurgical industry as a component of powder cover mixtures and insulation inserts, heat insulation parts and exothermical mixtures. The most important components in the mixtures are light micro spheres – cenospheres and heavy micro spheres – plerospheres. The micro spheres significantly improve properties of the powder cover mixtures.

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

    Directory of Open Access Journals (Sweden)

    Vilches, L. F.

    2005-09-01

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

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

  8. Injection of coal fly ash slurry in deep saline formations for improved CO2 confinement : a theoretical concept

    OpenAIRE

    Doucet, F.J.; Mlambo, T.K.; Van der Merwe, Elizabet Margaretha; Altermann, Wladyslaw

    2014-01-01

    98% of South Africa?s total CO2 geological storage capacity is in the form of deep saline formations located off-shore, while the remaining 2% is situated on-shore. Such formations may not have a similar proven sealing capacity to that of depleted gas and oil reservoirs, and the country must give due consideration to every theoretically conceivable option for CO2 storage. This paper discusses a theoretical concept whereby coal fly ash slurries, composed of homogeneously-sized...

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

    Directory of Open Access Journals (Sweden)

    Christian Ulrichs

    2009-01-01

    Full Text Available Problem statement: One focus in recent atmospheric pollution research is on fine Particle Matter (PM, especially as result of increasing traffic and anthropogenic activity in urban areas. Here, the impact on animal and human health has been in the center of many studies. Despite the fact that PM depositions can affect plants on the long term, there are only few studies about the impact on plants conducted. Approach: Therefore we studied the impact of PM on plants, using naturally occurring silica dusts (diatomaceous earth and hard Coal Fly Ash (CFA from burning processes. Dusts were applied onto Brassica chinensis L. using a simple duster (covering upper leaf surfaces or electrostatically (covering leaf upper and -underside. Results: Main components of the tested CFA are SO42-, K, Ca and NH4+. The pH value of eluates was found to be around 9.5 in CFA and 5.7 in silica. B. chinensis was insensitive towards the high pH and showed no growth reduction when grown in silica or CFA substrate. PM deposition on leaf surfaces results through shading in a reduced photosynthetic activity. The reduction is relatively higher at higher light intensities. Photosynthesis stays reduced after removal of silica PM from leaf surfaces. We assume that stomata get cloaked by small particles and that silica absorbs lipids from the epicuticle resulting in a general stress reaction. Smaller sized silica particles resulted in a higher reduction of CO2-absorption. Next to particle size is the photosynthesis negatively correlated with exposure time for silica PM. The chlorophyll fluorescence data indicate that dust-covered leaves exhibited significantly lower quantum yield of PS II and a reduced quantum efficiency of PS II and therefore supported the gas exchange data. Conclusion: Reduced photosynthetic performance would be expected to reduce growth and productivity of B. chinensis. In contrast to silica hard coal fly ash showed only a reduction of photosynthesis through shading but did not have any long time effects after washing them off.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-06-01

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

  11. Processing and kinetics studies on the alumina enrichment of coal fly ash by fractionating silicon dioxide as nano particles

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Guanghui; Teng, Wei; Wang, Xianggang; Xu, Peng [Applied Chemistry Department, Xi' an University of Architecture and Technology, Xi' an (China); Zhang, Hui [Pingshuo Coal Industry Company, Shanxi (China)

    2010-02-15

    Coal fly ash produced in the northern China is a potential bauxite substitute for aluminum production because of its high alumina content. However, this industrial application has been limited for its high silicon content. Alumina enrichment by removing silicon becomes a key technology for its utilization. A novel process was developed to fractionate the coal fly ash into high purity nano silicon particles and aluminum enriched residual ash. The procedure has major steps as sodium silicate dissolution with sodium hydroxide, first carbonation to remove impurities, second carbonation to precipitate silicon, and silicon precipitate recovery as a mesospheric nano particles product. Morphological and X-ray diffraction evidences indicated the glassy amorphous silicon content of the ash was dissolved in the sodium hydroxide solution whereas mullite remained in the residue. Kinetics study indicated that the second carbonation was a kinetically second order medium fast multi-phase reaction in which sodium silicate was precipitated as silicic acid. It was found that the reaction was controlled by the mass transferring resistance in the liquid membrane. These nano silicon dioxide particles were in size of 50 nm with a purity of 96%. Alumina content in process residue was slightly increased from 42.00 to 49.20%. Silicon dioxide content was reduced from 48.89 to 30.26%. Ratio of alumina/silica was increased from 0.86 to 1.63. (author)

  12. The synergistic effect in coal/biomass blend briquettes combustion on elements behavior in bottom ash using ICP-OES

    Energy Technology Data Exchange (ETDEWEB)

    Lazaroiu, G.; Frentiu, T.; Maescu, L.; Mihaltan, A.; Ponta, M.; Frentiu, M.; Cordos, E. [Universitatea Politehnica din Bucuresti, Bucharest (Romania)

    2009-05-15

    This paper focuses on the study of the synergistic effect in coal/biomass blend briquettes combustion on behavior of Al, As, Ba, Cd, Co. Cr, Cu, Fe, Ga, K, Mn, Mo, Ni, P, Pb, Si, V, W, Zn, Zr and characterization of raw materials and bottom ashes. The manufacturing of coal/biomass briquettes although not commonly used is an attractive approach, as briquettes combustion is more technologically advantageous than the fluidized bed combustion. In the same time this technology is a way to render valuable materials of low calorific power and results in diminishing polluting emission. Raw materials and briquettes from different blends of pitcoal/sawdust were subjected to combustion in a 55 kW-boiler. The total content of elements after digestion in the HNO{sub 3} - HF mixture and the content in water leachate at a solid/liquid ratio of 1:2 were determined both in raw materials and bottom ash by ICP-OES. The total content of elements was higher in pitcoal than in sawdust. The synergistic effect depends both on coal/biomass ratio in blend and element nature. The water leachable fraction of elements from ash decreased along with the increase of sawdust weight excepting macronutrients (K, P) and Si.

  13. Determination of trace elements in coal and fly ash by neutron activation analysis

    International Nuclear Information System (INIS)

    Concentration of 49 elements in NBS coal standard reference materials (SRM 1632 a and SRM 1635) and coal fly ash standard reference material (SRM 1633 a) were determined by instrumental neutron activation analysis (INAA). Each sample (ca. (25 -- 150) mg) was irradiated for short time (2 min) at thermal neutron flux 1.5 x 1012 n cm-2 s-1 and for long time (5 h) at thermal neutron flux 3.2 x 1012 n cm2 s-1 in Musashi Institute of Technology Research Reactor (MITRR). Gamma-ray spectra from short time irradiation samples were taken for 4 min after (2 -- 15) min after irradiation and for 15 min after (8 -- 70) min after irradiation using a Ge(Li) detector coupled to an 8192 multi-channel analyzer and a mini-computer (GAMA system). Gamma-ray spectra from long time irradiation samples were taken for about 2 h after (3 -- 12) d after irradiation and for about 10 h after (15 -- 60) d after irradiation. The analyzed values were in good agreement with NBS certified values except for a few elements. In order to improve the sensitivity of detection of some elements, long time irradiation samples were also counted by means of an anticoincidence counting method or a coincidence counting method with a Ge(Li) detector and a well-type NaI(Tl) detector. Concentrations of 12 elements (Pr, Nd, Rb, Th, Cr, Ce, Fe, Hg, Zr, Sr, Ni, Zn) were determined by the anticoincidence counting method and y the anticoincidence counting method and concentrations of 3 elements (Ba, Hf, Se) were determined by the coincidence counting method. (author)

  14. Composition and leachability of trace elements in coal ash and their migration in ground water at thermal power plant site at Manuguru

    International Nuclear Information System (INIS)

    The Heavy Water Board at Manuguru has a captive power plant using 2500 tpd of coal producing about 1000 tpd of ash. The possible toxic metal contamination of ground water due to leaching of the ash (so that toxic elements do not seep through one pond and contaminate the ground water) are assessed. Samples of coal, fly ash, bottom ash, ash pond overflow water, river water, ash pond slurry, soil (surface and depth) were analysed for major and trace element contents using EDXRF, INAA, AAS, and Anodic Stripping Voltammetry. The cation exchange capacity of the underlying soil and the fly ash were determined by standard method using calcium as the cation indicator. The redox potential and the pH of the samples were measured by using Pt/Mo and glass/calomel system respectively. The size distribution of fly ash particles were also determined. The study conclusively shows that the leach percent being very small and the soil having good cation exchange capacity there is negligible probability of contamination of ground water from ash pond and therefore there is no dire need for providing any impervious lining for the ash pond. (author). 23 refs., 19 tabs., 16 figs., 1 appendix

  15. Co-combustion of pulverized coal and solid recovered fuel in an entrained flow reactor- General combustion and ash behavior

    DEFF Research Database (Denmark)

    Wu, Hao; Glarborg, Peter

    2011-01-01

    Co-combustion of a bituminous coal and a solid recovered fuel (SRF) was carried out in an entrained flow reactor, and the influence of additives such as NaCl, PVC, ammonium sulphate, and kaolinite on co-combustion was investigated. The co-combustion experiments were carried out with SRF shares of 7.9 wt.%, 14.8 wt.% and 25 wt.%, respectively. The effect of additives was evaluated by maintaining the share of secondary fuel (mixture of SRF and additive) at 14.8 wt.%. The experimental results showed that the fuel burnout, NO and SO2 emission in co-combustion of coal and SRF were decreased with increasing share of SRF. The majority of the additives inhibited the burnout, except for NaCl which seemed to have a promoting effect. The impact of additives on NO emission was mostly insignificant, except for ammonium sulphate which greatly reduced the NO emission. For SO2 emission, it was found that all of the additives increased the S-retention in ash. Analysis of the bulk composition of fly ash from different experiments indicated that the majority of S and Cl in the fuels were released to gas phase during combustion, whereas the K and Na in the fuels were mainly retained in ash. When co-firing coal and SRF, approximately 99 wt.% of the K and Na in fly ash was present in water insoluble form such as aluminosilicates or silicates. The addition of NaCl, PVC, and ammonium sulphate generally promoted the vaporization of Na and K, resulting in an increased formation of water soluble alkalis such as alkali chlorides or sulphates. The vaporization degree of Na and K was found to be correlated during the experiments, suggesting an interaction between the vaporization of Na and K during pulverized fuel combustion. By collecting deposits on an air-cooled probe during the experiments, it was found that the ash deposition propensity in co-combustion was decreased with increasing share of SRF. The addition of NaCl and PVC significantly increased the ash deposition propensity, whereas the addition of ammonium sulphate or kaolinite showed a slight reducing effect. The chlorine content in the deposits generally implied a low corrosion potential during co-combustion of coal and SRF, except for the experiments with NaCl or PVC addition.

  16. Coal fly ash supported nZnO for the sorption of triphenyltin chloride/

    Directory of Open Access Journals (Sweden)

    Ayanda Olushola S.

    2015-03-01

    Full Text Available A laboratory study was performed to study the effects of various operating factors, viz. adsorbent dose, contact time, solution pH, stirring speed, initial concentration and temperature on the adsorption of triphenyltin chloride (TPT onto coal fly ash supported nZnO (CFAZ. The adsorption capacity increases with increase in the adsorbent amount, contact time, pH, stirring speed and initial TPT concentration, and decrease with increase in the solution temperature. The adsorption data have been analyzed by Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (D-R adsorption models to determine the mechanistic parameters associated with the adsorption process while the kinetic data were analyzed by pseudo first-order, pseudo second-order, Elovich, fractional power and intraparticle diffusivity kinetic models. The thermodynamic parameters of the process were also determined. The results of this study show that 0.5 g of CFAZ was able to remove up to 99.60% of TPT from contaminated natural seawater at 60 min contact time, stirring speed of 200 rpm and at a pH of 8. It was also found that the equilibrium and kinetic data fitted better to Freundlich and pseudo second-order models, respectively. It can therefore be concluded that CFAZ can be effectively used for shipyard process wastewater treatment

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

    Directory of Open Access Journals (Sweden)

    Prasert Pavasant

    2010-03-01

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

  18. The internal microstructure and fibrous mineralogy of fly ash from coal-burning power stations

    International Nuclear Information System (INIS)

    Coal fly ash (CFA) is a significant environmental pollutant that presents a respiratory hazard when airborne. Although previous studies have identified the mineral components of CFA, there is a paucity of information on the structural habits of these minerals. Samples from UK, Polish and Chinese power stations were studied to further our understanding of the factors that affect CFA geochemistry and mineralogy. ICP-MS, FE-SEM/EDX, XRD, and laser diffraction were used to study physicochemical characteristics. Analysis revealed important differences in the elemental compositions and particle size distributions of samples between sites. Microscopy of HF acid-etched CFA revealed the mullite present possesses a fibrous habit; fibres ranged in length between 1 and 10 ?m. Respirable particles (<10 ?m) were frequently observed to contain fibrous mullite. We propose that the biopersistence of these refractory fibres in the lung environment could be contributing towards chronic lung diseases seen in communities and individuals continually exposed to high levels of CFA. - Highlights: ? Chinese CFA had a greater crystalline mineral content and smaller particle size. ? Mullite and quartz, two hazardous minerals, recrystallise from glass melt particles. ? Mullite revealed a fibrous habit, with fibres 1-10 ?m in length and 0.5-1 ?m in width. - Chinese CFA possessed a greater crystalline mineral content and smaller particle size than UK and Polish CFA, the fibrous mullite prlish CFA, the fibrous mullite prhiesent displayed a high aspect-ratio and thus is likely to be a respiratory hazard in vivo.

  19. Coal fly ash as a source of iron in atmospheric dust.

    Science.gov (United States)

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

    2012-02-21

    Anthropogenic coal fly ash (FA) aerosol may represent a significant source of bioavailable iron in the open ocean. Few measurements have been made that compare the solubility of atmospheric iron from anthropogenic aerosols and other sources. We report here an investigation of iron dissolution for three FA samples in acidic aqueous solutions and compare the solubilities with that of Arizona test dust (AZTD), a reference material for mineral dust. The effects of pH, simulated cloud processing, and solar radiation on iron solubility have been explored. Similar to previously reported results on mineral dust, iron in aluminosilicate phases provides the predominant component of dissolved iron. Iron solubility of FA is substantially higher than of the crystalline minerals comprising AZTD. Simulated atmospheric processing elevates iron solubility due to significant changes in the morphology of aluminosilicate glass, a dominant material in FA particles. Iron is continuously released into the aqueous solution as FA particles break up into smaller fragments. These results suggest that the assessment of dissolved atmospheric iron deposition fluxes and their effect on the biogeochemistry at the ocean surface should be constrained by the source, environmental pH, iron speciation, and solar radiation. PMID:22260270

  20. Formation of linde F zeolite by KOH treatment of coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Miyaji, F.; Murakami, T.; Suyama, Y. [Shimane University, Shimane (Japan). Faculty of Science & Engineering

    2009-05-15

    Zeolitic products formed by hydrothermal treatment of coal fly ash (FA) with KOH aqueous solution under various reaction conditions were examined. Only linde F-type zeolite (K{sub 2}Al{sub 2}Si{sub 2}O{sub 8} {center_dot} 3H{sub 2}O) was newly formed at atmospheric pressure, except formation of a small amount of kalsilite (KAlSiO{sub 4}) at longer reaction time. The yield of the linde F zeolite was highest when reaction time, temperature, KOH concentration and (KOH solution/FA) ratio were 48 h, 95 {sup o}C, 8 mol dm{sup -3} and 25 ml g{sup -1}, respectively. In this case, the original FA spheres were almost completely dissolved out, and regular prisms of the linde F zeolite crystal with 0.5 to 1 mu m in width and 1 to a few mu m in length were formed. The specific surface area and cation exchange capacity of the FA-derived linde F zeolite were 20.2 m{sup 2} g{sup -1} and 2.3 meq g{sup -1}, respectively.

  1. Characterization of fly ash from full-scale demonstration of sorbent injection for mercury control on coal-fired power plants

    Energy Technology Data Exchange (ETDEWEB)

    Senior, Constance [Reaction Engineering International, 77 W. 200 S., Suite 210, Salt Lake City, UT 84101 (United States); Bustard, C. Jean; Durham, Michael; Baldrey, Kenneth [ADA Environmental Solutions, LLC, 8100 SouthPark Way, B-1, Littleton, CO 80120 (United States); Michaud, David [WE Energies, 333 W. Everett Street, Milwaukee, WI 53203 (United States)

    2004-06-15

    With impending regulation of mercury from coal-fired power plants, it is important to concentrate efforts on the most mature retrofit control technologies. Injection of powdered activated carbon (PAC) has been deemed the most mature technology, but has until recently only been demonstrated in bench- and pilot-scale experiments. This paper presents some of the results from a field evaluation program of sorbent injection upstream of existing particulate control devices (PCDs). An important component of the field demonstration program is to characterize the fly ash that results from injection of PAC upstream of a baghouse or electrostatic precipitator (ESP). Leaching analyses were performed on fly ash collected during two different field demonstrations; one fly ash was derived from bituminous coal and the other from a subbituminous coal. Several widely accepted leaching methods were used in order to assess the stability of the ash by-product in landfill situations; other ash characterization tests were also used in the study. Little or no detectable Hg was leached as a result of the various leaching protocols. The subbituminous ash conformed to the ASTM C-618 standard for Class C fly ash, but did not pass the Foam Index Test that is also required for sale of this ash for use in concrete formulation.

  2. Lead in children's blood is mainly caused by coal-fired ash after phasing out of leaded gasoline in Shanghai.

    Science.gov (United States)

    Liang, Feng; Zhang, Guilin; Tan, Mingguang; Yan, Chonghuai; Li, Xiaolin; Li, Yulan; Li, Yan; Zhang, Yuanmao; Shan, Zuci

    2010-06-15

    Lead (Pb) is a highly toxic element to the human body. After phasing out of leaded gasoline we find that the blood lead level of children strongly correlates with the lead concentration in atmospheric particles, and the latter correlates with the coal consumption instead of leaded gasoline. Combined with the (207)Pb/(206)Pb ratio measurements, we find that the coal consumption fly ash is a dominate source of Pb exposure to children in Shanghai, rather than vehicle exhaust, metallurgic dust, paint dust, and drinking water. Those particles are absorbed to children's blood via breathing and digesting their deposition on ground by hand-to-mouth activities. Probably the same situation occurs in other large cities of developing countries where the structure of energy supply is mainly based on coal-combustion. PMID:20536267

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

    OpenAIRE

    Kisi? Dragica M.; Mileti? Saša R.; Radonji? Vladimir D.; Radanovi? Sanja B.; Filipovic Jelena Z.; Gržeti? Ivan A.

    2013-01-01

    Serbian thermal power plants (TPPs) produce siliceous fly ash from lignite in the quantity of approximately 6 million tons per year. The potential market for the use of fly ash is operational, but for the time being, only used by cement producers. Fly ash radioactivity could be one of the major points of concern when larger use of fly ash is planned, particularly in the Serbian construction industry. Radioactivity measurements have been conducted regularly ...

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

    Energy Technology Data Exchange (ETDEWEB)

    Brubaker, Tonya M; Stewart, Brian W; Capo, Rosemary C; Schroeder, Karl T; Chapman, Elizabeth C; Spivak-Birndorf, Lev J; Vesper, Dorothy J; Cardone, Carol R; Rohar, Paul C

    2013-05-01

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

  5. Microsphere zeolite materials derived from coal fly ash cenospheres as precursors to mineral-like aluminosilicate hosts for {sup 135,137}Cs and {sup 90}Sr

    Energy Technology Data Exchange (ETDEWEB)

    Vereshchagina, Tatiana A., E-mail: tatiana@icct.ru [Institute of Chemistry and Chemical Technology, Siberian Branch of the Russian Academy of Sciences, 50/24 Akademgorodok, Krasnoyarsk 660036 (Russian Federation); Vereshchagin, Sergei N., E-mail: snv@icct.ru [Institute of Chemistry and Chemical Technology, Siberian Branch of the Russian Academy of Sciences, 50/24 Akademgorodok, Krasnoyarsk 660036 (Russian Federation); Shishkina, Nina N., E-mail: ninash@icct.ru [Institute of Chemistry and Chemical Technology, Siberian Branch of the Russian Academy of Sciences, 50/24 Akademgorodok, Krasnoyarsk 660036 (Russian Federation); Vasilieva, Nataly G., E-mail: vng@icct.ru [Institute of Chemistry and Chemical Technology, Siberian Branch of the Russian Academy of Sciences, 50/24 Akademgorodok, Krasnoyarsk 660036 (Russian Federation); Solovyov, Leonid A., E-mail: leosol@icct.ru [Institute of Chemistry and Chemical Technology, Siberian Branch of the Russian Academy of Sciences, 50/24 Akademgorodok, Krasnoyarsk 660036 (Russian Federation); Anshits, Alexander G., E-mail: anshits@icct.ru [Institute of Chemistry and Chemical Technology, Siberian Branch of the Russian Academy of Sciences, 50/24 Akademgorodok, Krasnoyarsk 660036 (Russian Federation); Department of Chemistry, Siberian Federal University, 79 Svobodnyi Avenue, Krasnoyarsk 660041 (Russian Federation)

    2013-06-15

    Hollow microsphere zeolite materials with a bilayered zeolite/glass crystalline shell bearing NaP1 zeolite were synthesized by the hydrothermal treatment of coal fly ash cenospheres (Si/Al = 2.7) in an alkaline medium. Cs{sup +} and/or Sr{sup 2+} forms of zeolitized cenospheres with the different Cs{sup +} and/or Sr{sup 2+} loading were prepared by the ion exchange from nitrate solutions. The resulted (Cs,Na)P1, (Sr,Na)P1 and (Cs,Sr,Na)P1 bearing microsphere zeolites were converted to glass ceramics by heating at 900–1000 °C. The differential scanning calorimetry and quantitative phase analysis were used to monitor the solid-phase transformation of the initial and ion exchanged zeolite materials. It was established that the final solidified forms of Cs{sup +} and/or Sr{sup 2+} are glass–crystalline ceramic materials based on pollucite–nepheline, Sr-feldspar–nepheline and Sr-feldspar–pollucite composites including ?60 wt.% of the major host phases (pollucite, Sr-feldspar) and 10–20 wt.% of glass. The {sup 137}Cs leaching rate of 4.1 × 10{sup ?7} g cm{sup ?2} day{sup ?1} was determined for the pollucite glass–ceramic according to Russian State Standard (GOST) No. 52126 P-2003 (7 day, 25 °C, distilled water)

  6. Microsphere zeolite materials derived from coal fly ash cenospheres as precursors to mineral-like aluminosilicate hosts for 135,137Cs and 90Sr

    Science.gov (United States)

    Vereshchagina, Tatiana A.; Vereshchagin, Sergei N.; Shishkina, Nina N.; Vasilieva, Nataly G.; Solovyov, Leonid A.; Anshits, Alexander G.

    2013-06-01

    Hollow microsphere zeolite materials with a bilayered zeolite/glass crystalline shell bearing NaP1 zeolite were synthesized by the hydrothermal treatment of coal fly ash cenospheres (Si/Al = 2.7) in an alkaline medium. Cs+ and/or Sr2+ forms of zeolitized cenospheres with the different Cs+ and/or Sr2+ loading were prepared by the ion exchange from nitrate solutions. The resulted (Cs,Na)P1, (Sr,Na)P1 and (Cs,Sr,Na)P1 bearing microsphere zeolites were converted to glass ceramics by heating at 900-1000 °C. The differential scanning calorimetry and quantitative phase analysis were used to monitor the solid-phase transformation of the initial and ion exchanged zeolite materials. It was established that the final solidified forms of Cs+ and/or Sr2+ are glass-crystalline ceramic materials based on pollucite-nepheline, Sr-feldspar-nepheline and Sr-feldspar-pollucite composites including ˜60 wt.% of the major host phases (pollucite, Sr-feldspar) and 10-20 wt.% of glass. The 137Cs leaching rate of 4.1 × 10-7 g cm-2 day-1 was determined for the pollucite glass-ceramic according to Russian State Standard (GOST) No. 52126 P-2003 (7 day, 25 °C, distilled water).

  7. Microsphere zeolite materials derived from coal fly ash cenospheres as precursors to mineral-like aluminosilicate hosts for 135,137Cs and 90Sr

    International Nuclear Information System (INIS)

    Hollow microsphere zeolite materials with a bilayered zeolite/glass crystalline shell bearing NaP1 zeolite were synthesized by the hydrothermal treatment of coal fly ash cenospheres (Si/Al = 2.7) in an alkaline medium. Cs+ and/or Sr2+ forms of zeolitized cenospheres with the different Cs+ and/or Sr2+ loading were prepared by the ion exchange from nitrate solutions. The resulted (Cs,Na)P1, (Sr,Na)P1 and (Cs,Sr,Na)P1 bearing microsphere zeolites were converted to glass ceramics by heating at 900–1000 °C. The differential scanning calorimetry and quantitative phase analysis were used to monitor the solid-phase transformation of the initial and ion exchanged zeolite materials. It was established that the final solidified forms of Cs+ and/or Sr2+ are glass–crystalline ceramic materials based on pollucite–nepheline, Sr-feldspar–nepheline and Sr-feldspar–pollucite composites including ?60 wt.% of the major host phases (pollucite, Sr-feldspar) and 10–20 wt.% of glass. The 137Cs leaching rate of 4.1 × 10?7 g cm?2 day?1 was determined for the pollucite glass–ceramic according to Russian State Standard (GOST) No. 52126 P-2003 (7 day, 25 °C, distilled water)

  8. Genotoxicity of coal fly ash, assessed in vitro in Salmonella typhimurium and human lymphocytes, and in vivo in an occupationally exposed population.

    Science.gov (United States)

    Kleinjans, J C; Janssen, Y M; van Agen, B; Hageman, G J; Schreurs, J G

    1989-09-01

    Fly ash as a product of coal combustion is known to contain various mutagenic substances, but genotoxic properties, especially of the particular (larger-size) fly ash fraction which is electrostatically precipitated (ESP) in the energy plant, have hardly been investigated. While smaller-size fly ash particles escape through the stack during powder coal combustion, the ESP fraction is collected and used for the manufacturing, for instance according to the Lytag process, of secondary products which can serve several construction purposes. Since fly ash as well as fly ash products are generally introduced into the human environment, a study of possible genotoxic effects to human DNA is indicated. Mutagenic properties of ESP fly ash, as well as of the Lytag product, were investigated by means of the Salmonella microsome assay. The capacity to cause human chromosome damage of both ESP fly ash and Lytag dust was studied in vitro by application of the sister-chromatid exchange (SCE) test using human lymphocytes. Furthermore, effects of ESP fly ash/Lytag dust on the incidence of SCE in peripheral lymphocytes in vivo were measured in an occupationally exposed, male population, using individually matched employees from a flour-processing industry as the control population. It is demonstrated that ultrasonically treated DMSO extracts of ESP fly ash are slightly mutagenic to Salmonella tester strains TA97 and TA102. Lytag dust is effective in inducing reversions in all tester strains. Furthermore, it appeared that both compounds significantly increase the SCE frequency of human lymphocytes after incubation in vitro in comparison to non-exposed cells. Also, peripheral lymphocytes of the occupationally exposed population show a considerably higher incidence of SCE than the control population. Major disturbing factors in assessing the effects of occupational exposure to fly ash/Lytag dust on lymphocyte SCE frequency appeared to be smoking behavior and alcohol consumption. It is concluded that exposure to fly ash from powder coal combustion implies a moderate genotoxic risk to man. PMID:2671713

  9. Evaluation of the use of modified coal ash as a potential sorbent for organic waste streams

    Energy Technology Data Exchange (ETDEWEB)

    Woolard, C.D.; Strong, J.; Erasmus, C.R. [University of Port Elizabeth, Port Elizabeth (South Africa). Dept. of Chemistry

    2002-07-01

    Fly ash was modified by hydrothermal treatment with 7 M NaOH. The resultant product displayed an 8-fold increase in surface area. The primary crystalline component of the modified fly ash was identified by X-ray diffraction to be hydroxysodalite (Na{sub 6}Al{sub 6}Si{sub 6}O{sub 24}.8H{sub 2}O). The cation exchange capacity of the modified ash was significantly increased over that of the raw fly ash (188 vs 2 meq g{sup -1}). Adsorption experiments showed that the modified fly ash adsorbed a cationic dye (methylene blue) to a much greater extent than an anionic dye (alizarin sulfonate). Saturation adsorption revealed that the capacity of the ash for triethylene blue had increased 10-fold during modification when compared to the raw ash. Adsorption is thus ascribed to be a surface effect rather than involving incorporation into the channels of the hydroxysodalite structure.

  10. Synthesis of zeolite from Italian coal fly ash: Differences in crystallization temperature using seawater instead of distilled water

    International Nuclear Information System (INIS)

    In this study Italian coal fly ash was converted into several types of zeolite in laboratory experiments with temperatures of crystallization ranging from 35 up to 90 deg. C. Distilled and seawater were used during the hydrothermal synthesis process in separate experiments, after a pre-treatment fusion with NaOH. The results indicate that zeolites could be formed from different kind of Italian coal fly ash at low temperature of crystallization using both distilled and seawater. SEM data and the powder patterns of X-ray diffraction analysis show that faujasite, zeolite ZK-5 and sodalite were synthesized when using both distilled and seawater; zeolite A crystallized only using distilled water. In particular the experiments indicate that the synthesis of zeolite X and zeolite ZK-5 takes place at lower temperatures when using seawater (35 and 45 deg. C, respectively). The formation of sodalite is always competitive with zeolite X which shows a metastable behaviour at higher temperatures (70-90 deg. C). The chemical composition of the fly ash source could be responsible of the differences on the starting time of synthesized zeolite with distilled water, in any case our data show that the formation of specific zeolites takes place always at lower temperatures when using seawater.

  11. Synthesis of MCM-41 from coal fly ash by a green approach: influence of synthesis pH.

    Science.gov (United States)

    Hui, K S; Chao, C Y H

    2006-09-21

    The present study reports a green synthesis method for preparing pure (free of fly ash) and ordered MCM-41 materials from coal fly ash at room temperature (25 degrees C) during 24 h of reaction. It was shown that the impurities in the coal fly ash were not detrimental to the formation of MCM-41 at the tested conditions. The influence of initial synthesis pH on material properties of calcined MCM-41 samples was investigated by various techniques such as XRF, XPS, XRD, FTIR, DR-UV-vis, solid state NMR, N2 physisorption, TG-DTA, SEM and TEM. The experimental results showed that the amount of trace elements such as Al, Na, Ti and Fe incorporated into the sample increased with synthesis pH value. More aluminum species were incorporated with tetrahedral coordination in the framework under a high pH value. The particle size of the sample decreased with the synthesis pH value. Samples synthesized at high pH values had a larger pore size and were more hydrothermally stable than those at low pH values. From thermal analysis, it was observed that the synthesized MCM-41 samples showed a high thermal stability. These properties made the synthesized MCM-41 suitable for further processing into more useful materials in a wide range of applications. PMID:16647813

  12. An assessment of the long-term environmental impacts of reusing alkaline clay on coal refuse piles with a dynamic solute transport model at a watershed scale

    Science.gov (United States)

    Xu, Y.; Liang, X.; Davis, T. W.; Patterson, J.; Jaw, F. K.; Koranchie-Boah, P.

    2011-12-01

    Coal refuse piles play a significant role in producing acid mining drainage (AMD) that deteriorates water quality at a watershed scale. The waste produced from coal refuse piles results in a decrease of the pH value in soil water and river flow. Metal compounds, such as ferric and ferrous solutions, are also continuously released from the coal pile due to the extensive and complicated chemical reactions in the acidic environment. Alkaline clay, a byproduct of alumina refining process, has a high residual pH in the material. If the alkaline clay is used innovatively with the coal mine refuse, the problems associated with each (e.g., high and low pH values) are likely to be effectively resolved. In addition, the solubility of the sulfur and iron will be reduced significantly. This will effectively eliminate the AMD problem at the coal refuse pile and improve the water quality at the watershed scale. This study investigates the long-term impacts of the combined mixture (i.e., alkaline clay + coal refuse) on the environment (e.g., in the soil column and in the river system) through systematic modeling simulations in a combination with field measurements. In particular, a dynamic solute transport model that accounts for processes of the pyrite oxidation, oxygen diffusion, absorption, desorption, and advection is developed and is coupled with the Distributed Hydrology Soil and Vegetation Model (DHSVM) to assess the environmental impacts at the watershed scale. The model-simulated sulfur and iron concentrations are compared with field observations and the long-term impacts of the combined mixture (i.e., alkaline clay + coal refuse) on the environment are investigated. This study paves the way for monitoring and assessing the impacts of the reuse of the alkaline clay and refuse mixture on the environment at a watershed scale.

  13. Coal fly ash as raw material for the manufacture of geopolymer-based products.

    Science.gov (United States)

    Andini, S; Cioffi, R; Colangelo, F; Grieco, T; Montagnaro, F; Santoro, L

    2008-01-01

    In this work coal fly ash has been employed for the synthesis of geopolymers. Two different systems with silica/alumina ratios stoichiometric for the formation of polysialatesiloxo (PSS, SiO2/Al2O3=4) and polysialatedisiloxo (PSDS, SiO2/Al2O3=6) have been prepared. The alkali metal hydroxide (NaOH or KOH) necessary to start polycondensation has been added in the right amount as concentrated aqueous solution to each of the two systems. The concentration of each alkali metal solution has been adjusted in order to have the right liquid volume to ensure constant workability. The systems have been cured at four different temperatures (25, 40, 60, and 85 degrees C) for several different times depending on the temperature (16-672 h at 25 degrees C; 72-336 h at 40 degrees C; 16-120 h at 60 degrees C and 1-6h at 85 degrees C). The products obtained in the different experimental conditions have been submitted to the quantitative determination of the extent of polycondensation through mass increase and loss on ignition, as well as to qualitative characterization by means of FT-IR spectroscopy. Furthermore, physico-structural and mechanical characterization has been carried out through microscopic observations and the determination of unconfined compressive strength, elasticity modulus, apparent density, porosity and specific surface area. The results have indicated that the systems under investigation are suited for the manufacture of pre-formed building blocks at room temperature. PMID:17382528

  14. Properties of geopolymer from circulating fluidized bed combustion coal bottom ash

    Energy Technology Data Exchange (ETDEWEB)

    Topcu, Ilker Bekir, E-mail: ilkerbt@ogu.edu.tr [Eskisehir Osmangazi University, Civil Engineering Department, 26480 Eskisehir (Turkey); Toprak, Mehmet Ugur [Eskisehir Osmangazi University, Civil Engineering Department, 26480 Eskisehir (Turkey)

    2011-01-25

    Research highlights: {yields} Dry cured geopolymers exhibit a heterogeneous and porous gel matrix. {yields} The Si/Na atomic ratio of the main reaction product (N-A-S-H gel) is close to 1. {yields} Low Si/Na ratio (0.5) correspond to a more crystalline stage of the N-A-S-H gel. {yields} N-A-S-H gel has small pores which facilitate the escape of moisture when it is heated. {yields} N-A-S-H gel became more amorphous, attaining higher Si/Al ratio of 4.54 at 800 deg. C. - Abstract: Compressive strength, atomic ratios and microstructure of geopolymer mortars (GM) made from circulating fluidized bed combustion (CFBC) coal bottom ash (CBA) were investigated to observe the effect of air curing at ambient temperature (AC) at 20 deg. C and 90% RH, dry curing (DC) at 80 deg. C and 40% RH for 20 h. The 28-d compressive strength of GM exposed to AC (GM-AC) and DC (GM-DC) were 26.23 and 24.14 MPa, respectively. The Si/Na atomic ratio of the main reaction product (N-A-S-H gel) was close to 1. Geopolymer gel (apparently crystalline) having low Si/Na ratio (0.5) may correspond to a more advanced or developed stage of the aluminosilicate gel. It was observed that the geopolymerization was completed before the N-A-S-H gel formed when Si/Na ratio of GM is close to 2. The color of the GM changed from pink to grey and the structure became denser with almost no pores, when the temperature increased from 400 to 800 deg. C. The N-A-S-H gel became more amorphous due to the sintering reactions attaining Si/Al and Si/Na ratios of 4.54 and 0.98, respectively.

  15. Properties of geopolymer from circulating fluidized bed combustion coal bottom ash

    International Nuclear Information System (INIS)

    Research highlights: ? Dry cured geopolymers exhibit a heterogeneous and porous gel matrix. ? The Si/Na atomic ratio of the main reaction product (N-A-S-H gel) is close to 1. ? Low Si/Na ratio (0.5) correspond to a more crystalline stage of the N-A-S-H gel. ? N-A-S-H gel has small pores which facilitate the escape of moisture when it is heated. ? N-A-S-H gel became more amorphous, attaining higher Si/Al ratio of 4.54 at 800 deg. C. - Abstract: Compressive strength, atomic ratios and microstructure of geopolymer mortars (GM) made from circulating fluidized bed combustion (CFBC) coal bottom ash (CBA) were investigated to observe the effect of air curing at ambient temperature (AC) at 20 deg. C and 90% RH, dry curing (DC) at 80 deg. C and 40% RH for 20 h. The 28-d compressive strength of GM exposed to AC (GM-AC) and DC (GM-DC) were 26.23 and 24.14 MPa, respectively. The Si/Na atomic ratio of the main reaction product (N-A-S-H gel) was close to 1. Geopolymer gel (apparently crystalline) having low Si/Na ratio (0.5) may correspond to a more advanced or developed stage of the aluminosilicate gel. It was observed that the geopolymerization was completed before the N-A-S-H gel formed when Si/Na ratio of GM is close to 2. The color of the GM changed from pink to grey and the structure became denser with almost no pores, when the temperature increased from 400 to 800 deg. C. The N-A-S-H gel became more amorphous due to the sintering reactions attaining Si/Al and Si/Nactions attaining Si/Al and Si/Na ratios of 4.54 and 0.98, respectively.

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

    Directory of Open Access Journals (Sweden)

    Abdulhameed Umar Abubakar

    2012-11-01

    Full Text Available As Malaysia focuses its attention to the call for a “greener” culture, so did the engineers and those in the scientific community especially the construction industry who is a major contributor to the depletion of green house gases. The engineering and construction community has now taken up the challenge for the use of “green and recycled by-products” in construction. One of those by-products is the Coal Bottom Ash (CBA from thermal power plants that faces an increasing production running into hundreds of thousand tonnes in Malaysia alone, and its method of disposal is relegated to landfills alone with no other commercial usage. The construction industry is now forced to rethink on the utilization of the industrial by-products as supplementary materials due to the continuous depletion of natural aggregates in construction. A significant amount of research has been conducted elsewhere on CBA to ascertain its pozzolanic activity, compressive strength in concrete and mortar, durability, water absorption characteristics and density, in order to ensure its usage as a construction material. In this paper, a critical review of the strength characteristics of concrete and mortar as influenced by CBA as partial replacement of fine aggregate is presented based on the available information in the published literatures. Diverse physical and chemical properties of CBA from different power plants in Malaysia are also presented. The influence of different types, amounts and sources of CBA on the strength and bulk density of concrete is discussed. The setting time, workability and consistency as well as the advantages and disadvantages of using CBA in construction materials are also highlighted. An effective utilization of CBA in construction materials will significantly reduce the accumulation of the by-products in landfills and thus reduce environmental pollution.

  17. Determinação de enxofre em amostras vegetais por oxidação via seca em meio alcalino com detecção espectrofométrica Espectrofotometric determination of sulfur in plants using dry ash oxidation and alkaline oxidizers

    OpenAIRE

    Alexssandra Luiza Rodrigues Molina Rossete; Josiane Meire Tolotti Carneiro; Hugo Henrique Batagello; Juliana Graciela Giovannini Oliveira; José Albertino Bendassolli

    2011-01-01

    The sulphur take an essential role in plants and it is one of the main nutrients in several metabolic processes. The dry ash oxidation, using alkaline oxidizers agent, is the simplest and most economical form for the oxidation of Organic S to sulfate in plants. The objective of this work is to propose a method for sulfur determination in plants samples using dry ash oxidation and agent oxidizers alkaline. The quantification of S-SO4(2-) in samples was accomplished by turbidimetric method. The...

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

    Directory of Open Access Journals (Sweden)

    Bossert J.

    2004-01-01

    Full Text Available 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 polyurethane foam and C-fibers was 2.7±0.5 GPa and 4.5±1 MPa and 7.1±1 GPa and 9.3±2 MPa respectively.

  19. Strontium isotopes as tracers of airborne fly ash from coal-fired power plants

    International Nuclear Information System (INIS)

    The paper presents the results of a controlled greenhouse experiment in which a native desert plant, the brittlebush was grown on admixtures of desert soils and fly ash. The fly ash is strongly enriched in Sr and the brittlebush is a Sr accumulator. The data demonstrate that the brittlebush isotopically equilibrates with desert soils whose fly ash components are as low as 0.25% by weight, the fly ash Sr is apparently more available to the plant than Sr derived from the soils, and the difference between the 87Sr/86Sr ratio of the fly ash (0.70807) and soils (0.71097 to 0.71117) warrants further investigations in the natural environment to determine the practicality of this method as a natural tracer of fly ash in the environment

  20. Influence of additions of coal fly ash and quartz on hydrothermal solidification of blast furnace slag

    Energy Technology Data Exchange (ETDEWEB)

    Jing, Z.; Jin, F.; Hashida, T.; Yamasaki, N.; Ishida, E.H. [Tohoku University, Miyagi (Japan). Graduate School for Environmental Studies

    2008-07-15

    Blast furnace water-cooled slag (BFWS) has been solidified hydrothermally with tobermorite formation. The experimental results showed that the addition of fly ash and quartz was favorable to the formation of tobermorite, and the strength development of solidified body depended on both of the tobermorite formation and filling degree of formed tobermorite in the spaces between BFWS particles. The fly ash added appeared to have a higher reactivity than the quartz used during the initial hydrothermal processing due to the higher solubility of glassy phase in fly ash. The tobermorite formation seemed to be very sensitive to the fly ash content, e.g., the addition of fly ash 10-20 mass% was favorable to tobermorite formation, while the excessive addition of fly ash (> 20 mass%) appeared to impede the tobermorite formation. The excessive addition of quartz was also shown to exert a negative effect on the tobermorite formation, which causes strength deduction.

  1. Utilisation of different types of coal fly ash in the production of ceramic tiles

    OpenAIRE

    Kockal, N. U.

    2012-01-01

    The influence of varying proportions of different types of fly ash (used in place of feldspar) and different sintering temperatures on the sintered properties of ceramic tile bodies was evaluated. The results indicated that sintering ceramic tiles with a high fly ash content at a high temperature caused a decrease in the properties because of bloating. The ceramic samples containing a higher amount of fly ash that were sintered at low temperature exhibited lower water absorption, larger shrin...

  2. Evaluating risks to wildlife from coal fly ash incorporating recent advances in metals and metalloids risk assessment.

    Science.gov (United States)

    Meyer, Carolyn B; Schlekat, Tamar H; Walls, Suzanne J; Iannuzzi, Jacqueline; Souza, Marcy J

    2015-01-01

    Current scientific advances in metal and metalloid risk assessment were applied to evaluate risk to aquatic and riparian wildlife species potentially impacted by residual coal fly ash after cleanup of an unprecedented large ash release into an aquatic environment-the first assessment of its kind. Risk was evaluated using multiple lines of evidence (LOE), including 1) tissue-based risk assessment of inorganic concentrations in piscivorous and insectivorous bird eggs and raccoon organs, 2) deterministic and probabilistic diet-based risk estimates for 10 receptors species, 3) raccoon health metrics, and 4) tree swallow nest productivity measures. Innovative approaches included use of tissue-based toxicity reference values (TRVs), adjustment of bioavailability in the dietary uptake models (using sequential metal extractions in sediment), partitioning chemical species into uptake compartments (e.g., prey gut, nongut, sediment), incorporating uncertainty in both modeled dose and dietary TRVs, matching TRVs to chemical forms of constituents, and pairing these LOEs with reproductive success or health status of sensitive receptor species. The weight of evidence revealed that risk to wildlife from residual ash was low and that risk, though low, was most pronounced for insectivorous birds from exposure to Se and As. This information contributes to the debate surrounding coal combustion residue regulations prompted by this ash release. Because of the responsible party's proactive approach of applying state-of-the-art methods to assess risk using several LOEs that produced consistent results, and because of their inclusion of the regulating agencies in decisions at every step of the process, the risk assessment results were accepted, and an effective approach toward cleanup protective of the environment was quickly implemented. This study highlights the value of using multiple LOEs and the latest scientific advances to assist in timely decision making to obtain an effective remedy for an emergency spill. PMID:25158048

  3. Geochemical Partitioning of Major Elements in Brine Impacted Coal Fly Ash Residues

    OpenAIRE

    O. O. Fatoba; Petrik, L.F.; R. O. Akinyeye; W. M. Gitari; E. I. Iwuoha

    2013-01-01

    Fly ash-brine co-disposal technique has been considered as a way of disposing fly ash and brine (hyper-saline water) by some power stations in South Africa. This practice was aimed at using the fly ash to capture most of the elements in brine. However, the geochemical partitioning of the major elements in the waste materials after the fly ash-brine interaction has not been fully understood. This study focuses on understanding the geochemical partitioning of the major elements captured in the ...

  4. Synthesis of zeolite-P from coal fly ash derivative and its utilisation in mine-water remediation

    OpenAIRE

    Leslie F. Petrik; Gillian Balfour; Annabelle Ellendt; Wilson M. Gitari; Viswanath R.K. Vadapalli

    2010-01-01

    Solid residues resulting from the active treatment of acid mine drainage with coal fly ash were successfully converted to zeolite-P under mild hydrothermal treatment conditions. Scanning electron microscopy showed that the zeolite-P product was highly crystalline. The product had a high cation exchange capacity (178.7 meq / 100 g) and surface area (69.1 m2/g) and has potential application in waste-water treatment. A mineralogical analysis of the final product identified...

  5. Influence of a modification of the petcoke/coal ratio on the leachability of fly ash and slag produced from a large PCC power plant.

    Science.gov (United States)

    Izquierdo, Maria; Font, Oriol; Moreno, Natalia; Querol, Xavier; Huggins, Frank E; Alvarez, Esther; Diez, Sergi; Otero, Pedro; Ballesteros, Juan Carlos; Gimenez, Antonio

    2007-08-01

    Co-firing of coal with inexpensive secondary fuels such as petroleum coke is expected to increase in the near future in the EU given that it may provide certain economic and environmental benefits with respect to coal combustion. However, changes in the feed fuel composition of power plants may modify the bulk content and the speciation of a number of elements in fly ash and slag. Consequently, leachability of these byproducts also can be modified. This study is focused on identifying the changes in the environmental quality of co-fired fly ash and slag induced by a modification of the petcoke/coal ratio. Petcoke was found to increase the leachable content of V and Mo and to enhance the mobility of S and As. However, with the exception of these elements, the addition of this secondary fuel did not drastically modify the bulk composition or the overall leachability of the resulting fly ash and slag. PMID:17822098

  6. Natural radioactivity of ground waters and soil in the vicinity of the ash repository of the coal-fired power plant. Nikola Tesla A in Obrenovac, Yugoslavia

    Energy Technology Data Exchange (ETDEWEB)

    Vukovic, Z.; Madic, M.; Vukovic, D. [Institute of Nuclear Sciences Vinca, Belgrade (Yugoslavia)

    1996-11-01

    Radioactivity of U, Th and {sup 40}K has been investigated in the vicinity of the ash repository of coal-fired Nikola Tesla A power plant in Obrenovac (Yugoslavia). Using alpha and gamma spectrometry, luminescence spectrophotometry, it was found that the ash repository is a source of radionuclides of the uranium and thorium series; and these radionuclides were found in the ground water up to a distance of several hundred metres. The influence of the repository on the soil radioactivity was minimal.

  7. Mobility and Transport of Inorganic Species in Weathered Hydraulic Disposed Coal Fly Ash: An Insight from Geochemical Fractionation and Statistical Evaluation

    Directory of Open Access Journals (Sweden)

    S. A. Akinyemi

    2012-03-01

    Full Text Available

    A large volume of coal fly ash generated through combustion process has raised environmental concerns due to possible release of potentially toxic species to the surface and groundwater systems. The chemical partitioning and mobility of elements in the hydraulic disposed ash dump was investigated using modified sequential extraction scheme. The geochemical distribution of the investigated elements in 33 drilled core samples was determined by x-ray fluorescence and inductively coupled plasma mass spectrometry. The ternary plot of major elements as determined by XRF showed that hydraulic disposed ash cores are sialic, ferrosialic and ferrocalsialic in chemical composition. The relationship between SiO2 and chemical index of alteration (CIA showed low, moderate to high degree of weathering. These chemical compositions and degree of chemical weathering depend on the ash sampling point and ash interaction chemistry. The Na+ and K+ soluble salts showed evidence of leaching and downward migration in the water soluble fraction indicating that the hydraulic disposed ash dump is not a sustainable salt sink. The geochemical partitioning reveals that mobility and transport of potentially toxic metal species are governed by the pore water pH, ash interaction chemistry and the sampling point of the ash cores.  The chemical interaction of drilled core ash with the ingress CO2 and percolating rain water led to dissolution and co-precipitation of soluble major components in fly ash. This had led to incoherent patterns of elements in carbonate fraction of the ash cores.

    Key words: Modified sequential extraction; Hydraulic disposed ash; Chemical index of alteration; Pore water pH; Ash interaction chemistry; Moisture content; Chemical weathering

  8. Study on the correlation between chemical and mineral composition of coal ashes; Sekitanbaibun no kobutsu soseigakuteki kento kagakubutsu sosei to kobutsugakuteki sosei no sokan

    Energy Technology Data Exchange (ETDEWEB)

    Hirato, M.; Nagashima, S.; Okada, S. [Hachinohe Institute of Technology, Aomori (Japan)

    1996-10-28

    Coal ash is a substance that has been mixed into minerals in the earth`s crust during their coalification process. Estimation was made on what kinds of mineral composition have been mixed into coals. Noted first was the kinds of compounds contained in the ash, wherein the ratios of mass in the compounds and minerals were correlated, and selection was made on minerals which are thought correlated. The selection criterion was based on minerals containing silica, alumina, iron oxide, lime and magnesium as compounds. Then, a phase equilibrium line diagram was used to estimate compositions and melting points of minerals which are thought to have been produced from these compounds. By comparing the estimation with the measured melting points of the ashes, mineral compositions thought reasonable were all selected. Assumption was possible on minerals that are thought to have been transferred into coal ash. Compound indications of ashes from 29 kinds of the world`s typical coals were replaced with the subject minerals and expressed as mineral compositions. As a method of calculation, stoichiometric coefficients for each mineral were determined by taking material balance in atomic/molecular levels in masses of compound aggregates and mineral composition aggregates. 7 tabs.

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

    Directory of Open Access Journals (Sweden)

    Bilski J. et al.

    2012-04-01

    Full Text Available 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. Therefore, the aim of this study was to determine the effects of growth media containing differing concentration of FA and/or sphagnum peat moss (SPM on growth of selected plants. The following plant species have been tested: barley (Hordeum vulgare, oats (Avena sativa, rye (Secale cereale, wheat (Triticum aestivum, Regreen; a hybrid between wheatgrass (Agropyron cristatum and winter wheat (Triticum aestivum, Triticale; a hybrid between wheat (Triticum aestivum and rye (Secale cereale,, and perennial ryegrass (Lolium multiflorum. The addition of SPM to FA based plant growth media expressed ameliorative role, allowing the growth of seedlings on such media. In addition, our results indicate that the transfer of heavy metals from coal FA to plants and possibly to a food chain either did not exist or was very low.

  10. Preparation of Functionally Graded Materials (FGMs) Using Coal Fly Ash and NiCr-Based Alloy Powder by Spark Plasma Sintering (SPS)

    International Nuclear Information System (INIS)

    Functionally Graded Materials (FGMs) were prepared by spark plasma sintering (SPS) using coal fly ash and NiCr alloy powder. The coal fly ash was produced by the Misumi Coal Thermal Power Station (Chugoku Electric Power Co., Inc.), with 80 wt% nickel and 20 wt% chromium (Fukuda Metal Foil and Powder Co., Ltd.) used as source materials. The sintering temperature in the graphite die was 1000 deg. C. X-ray diffraction patterns of the sintered coal fly ash materials indicated that mullite (3Al2O3·2SiO2) and silica (SiO2) phases were predominant. Direct joining of coal fly ash and NiCr causes fracture at the interface. This is due to the mismatch in the thermal expansion coefficients (CTE). A crack in the FGM was observed between the two layers with a CTE difference of over 4.86x10-6 K-1, while a crack in the FGM was difficult to detect when the CTE difference was less than 2.77x10-6 K-1

  11. Mineralogical and elemental composition of fly ash from pilot scale fluidised bed combustion of lignite, bituminous coal, wood chips and their blends

    Energy Technology Data Exchange (ETDEWEB)

    Nikolaos Koukouzas; Jouni Hamalainen; Dimitra Papanikolaou; Antti Tourunen; Timo Jantti [Institute for Solid Fuels Technology and Applications, Ptolemais (Greece). Centre for Research and Technology Hellas

    2007-09-15

    The chemical and mineralogical composition of fly ash samples collected from different parts of a laboratory and a pilot scale CFB facility has been investigated. The fabric filter and the second cyclone of the two facilities were chosen as sampling points. The fuels used were Greek lignite (from the Florina basin), Polish coal and wood chips. Characterization of the fly ash samples was conducted by means of X-ray fluorescence (XRF), inductive coupled plasma-optical emission spectrometry (ICP-OES), thermogravimetric analysis (TGA), particle size distribution (PSD) and X-ray diffraction (XRD). According to the chemical analyses the produced fly ashes are rich in CaO. Moreover, SiO{sub 2} is the dominant oxide in fly ash with Al{sub 2}O{sub 3} and Fe{sub 2}O{sub 3} found in considerable quantities. Results obtained by XRD showed that the major mineral phase of fly ash is quartz, while other mineral phases that are occurred are maghemite, hematite, periclase, rutile, gehlenite and anhydrite. The ICP-OES analysis showed rather low levels of trace elements, especially for As and Cr, in many of the ashes included in this study compared to coal ash from fluidised bed combustion in general. 23 refs., 3 figs., 5 tabs.

  12. Removal of sulfuric acid mist from lead-acid battery plants by coal fly ash-based sorbents.

    Science.gov (United States)

    Shu, Yuehong; Wei, Xiangyu; Fang, Yu; Lan, Bingyan; Chen, Hongyu

    2015-04-01

    Sorbents from coal fly ash (CFA) activated by NaOH, CaO and H2O were prepared for H2SO4 mist removal from lead-acid battery plants. The effects of parameters including temperature, time, the ratios of CFA/activator and water/solid during sorbent preparation were investigated. It is found that the synthesized sorbents exhibit much higher removal capacity for H2SO4 mist when compared with that of raw coal fly ash and CaO except for H2O activated sorbent and this sorbent was hence excluded from the study because of its low capacity. The H2SO4 mist removal efficiency increases with the increasing of preparation time length and temperature. In addition, the ratios of CFA/activator and water/solid also impact the removal efficiency, and the optimum preparation conditions are identified as: a water/solid ratio of 10:1 at 120 °C for 10h, a CFA:CaO weight ratio of 10:1, and a NaOH solution concentration of 3 mol/L. The formation of rough surface structure and an increased surface area after NaOH/CaO activation favor the sorption of H2SO4 mist and possible sorption mechanisms might be electrostatic attractions and chemical precipitation between the surface of sorbents and H2SO4 mist. PMID:25603301

  13. Characteristics of zircons from volcanic ash-derived tonsteins in Late Permian coal fields of eastern Yunnan, China

    Science.gov (United States)

    Zhou, Y.; Ren, Y.; Tang, D.; Bohor, B.

    1994-01-01

    Kaolinitic tonsteins of altered synsedimentary volcanic ash-fall origin are well developed in the Late Permian coal-bearing formations of eastern Yunnan Province. Because of their unique origin, wide lateral extent, relatively constant thickness and sharp contacts with enclosing strata, great importance has been attached to these isochronous petrographic markers. In order to compare tonsteins with co-existing, non-cineritic claystones and characterize the individuality of tonsteins from different horizons for coal bed correlation, a semi-quantitative method was developed that is based on statistical analyses of the concentration and morphology of zircons and their spatial distribution patterns. This zircon-based analytical method also serves as a means for reconstructing volcanic ash-fall dispersal patterns. The results demonstrate that zircons from claystones of two different origins (i.e., tonstein and non-cineritic claystone) differ greatly in their relative abundances, crystal morphologies and spatial distribution patterns. Tonsteins from the same area but from different horizons are characterized by their own unique statistical patterns in terms of zircon concentration values and morphologic parameters (crystal length, width and the ratio of these values), thus facilitating stratigraphic correlation. Zircons from the same tonstein horizon also show continuous variation in these statistical patterns as a function of areal distribution, making it possible to identify the main path and direction in which the volcanic source materials were transported by prevailing winds. ?? 1994.

  14. 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.

    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 experiments show that a barrier composed of sand, Fe(0), and bentonite irreversibly immobilizes Cr. Concentrations fall from 25 mg Cr L-1 in the leachate to below detection limits (0.0025 mg Cr L-1) and solution pH increases by about two units. Solid-phase analytical techniques such as SEM, EDS, XPS, and TOFSIMS were used to characterize the barrier material prior to and after exposure to the Cr leachate. In the barrier material, Cr(III) was found associated with Fe(III)-oxides, as separate Cr oxides and as a Ca,Cr phase, probably Cachromite, CaCr2O4. The attenuating barrier can be an alternative to traditional liners and leachate collection systems at coal ash storage and disposal sites.

  15. Coal fly ash as adsorptive material for treatment of a real textile effluent: operating parameters and treatment efficiency.

    Science.gov (United States)

    Zaharia, Carmen; Suteu, Daniela

    2013-04-01

    The experimental results performed after the application of one single-stage treatment by sorption onto coal fly ash are evaluated in order to decolorize a real textile effluent of a private company specializing in manufacturing of cotton fabrics (i.e., sorption performance applied for a real textile effluent collected after the fabric dyeing, rinsing, and final finishing steps). The experiments are focused on studying the effect of initial textile effluent pH, adsorbent dose, temperature and adsorption time, considered as operating parameters of sorption process for high pollutant removals (e.g., organic pollutants as dyes, phenols, polymeric, and degradation compounds), and decoloration. The results indicate high values of decoloration degree (55.42-83.00%) and COD removal (44.44-61.11%) when it is worked at pH ?2 with coal ash dose of 12-40 g/L, temperature higher than 20-25 °C, and continuous static operating regime (with an initial agitation step of 3-5 min). The treated textile effluent fulfills the quality demand, and is recyclable, inside reused or discharged after a stage of neutralization (standard pH of 6.5-8.5 for all textile effluent discharges). Also, the final effluent is able to follow the common path to the central biological treatment plant (i.e., a centralized treatment plant for all companies acting in the industrial site area with mechanical-biological steps for wastewater treatment) or may be directly discharged in the nearly watercourse. PMID:22814960

  16. Separation of unburned carbon from coal fly ash through froth flotation; Sekitanbai no shisshiki datsutanso gijutsu kaihatsu shiken

    Energy Technology Data Exchange (ETDEWEB)

    Miwa, T. [Center for Coal Utilization, Japan, Tokyo (Japan); Murakami, T. [The Coal Mining Research Center, Japan, Tokyo (Japan)

    1996-09-01

    Coal ash tends to become containing more unburned carbon and porous substances depending on conditions of combustion, whose adverse effects to products due to water adsorbability, absorbability and color tones create obstacles in its utilization. Therefore, research and development works have been progressed on wet type carbon removing technology which is characterized in that coal is pulverized to preferable degrees and subjected to flotation. This paper reports the results obtained during fiscal 1995. The results may be summarized as follows: as a result of the comparison test on a column flotation machine and an FW type flotation machine of machine stirring type, the former machine showed better flotation efficiency; several methods were investigated on crushing as a treatment prior to flotation, whereas a mixer with greater circumferential speed and a homo mixer showed the highest efficiency; strength of the impact to the flotation efficiency was found to decrease in the order of pulp concentration > pretreatment time > collector addition ratio; and as a result of the evaluation on refined ash as a cement admixture and carbons as fuel, possibilities were found in them for practical application. 16 figs., 2 tabs.

  17. Practical use technology of coal ash (Poz-O-Tec); Sekitanbai no yuko riyo gijutsu (POZ-O-TEC)

    Energy Technology Data Exchange (ETDEWEB)

    Konno, K. [Center for Coal Utilization, Japan, Tokyo (Japan); Saito, Y. [Mitsui Mining Co. Ltd., Tokyo (Japan); Nagaya, Y. [Mitsui Construction Co. Ltd., Tokyo (Japan)

    1996-09-01

    In order to utilize more effectively coal ash whose generation amount is increasing year after year, studies have been made on a technology to manufacture and utilize a high-strength substance solidified under normal temperature by utilizing hydration reaction of pozzolan system (Poz-O-Tec). The study works have been done as a subsidy operation of the Agency of Natural Resources and Energy, and were completed in fiscal 1995. Poz-O-Tec is a wet powder made of coal ash and stack gas desulfurization sludge (gypsum) added and mixed with lime and an adequate amount of water, which solidifies by hydration as pozzolan does. The same method as used for ordinary sands may be used as the basic application method. Because this is the material whose strength increases after construction, thickness of construction may be reduced smaller than in constructions using soils and sands. Test constructions of about sixty cases have been carried out to date, typically represented in use as a road bed material, banking, and a base material for water-barrier gutters. High-strength solid material which is stable under normal temperature may be obtained by adjusting calcium content. As a result of its effectiveness in practical use having been verified, a certificate of technological judgment has been issued for the material by the Civil Engineering Research Center. 3 refs., 11 figs., 2 tabs.

  18. Kentucky Ash Education Site

    Science.gov (United States)

    This site from the University of Kentucky's Center for Applied Energy Research explains coal combustion byproducts such as fly ash, bottom ash, boiler slag and gypsum. The site also outlines how coal is used for electricity. Several animations will help users visualize how coal is processed at an electrical power plant.

  19. Utilisation of different types of coal fly ash in the production of ceramic tiles

    International Nuclear Information System (INIS)

    The influence of varying proportions of different types of fly ash (used in place of feldspar) and different sintering temperatures on the sintered properties of ceramic tile bodies was evaluated. The results indicated that sintering ceramic tiles with a high fly ash content at a high temperature caused a decrease in the properties because of bloating. The ceramic samples containing a higher amount of fly ash that were sintered at low temperature exhibited lower water absorption, larger shrinkage and strength because of the densification observed also in microstructural investigation. (Author) 25 refs.

  20. Geochemical investigations of metals release from submerged coal fly ash using extended elutriate tests

    Energy Technology Data Exchange (ETDEWEB)

    Bednar, A.J.; Chappell, M.A.; Seiter, J.M.; Stanley, J.K.; Averett, D.E.; Jones, W.T.; Pettway, B.A.; Kennedy, A.J.; Hendrix, S.H.; Steevens, J.A. [Engineering Research & Development Center, Vicksburg, MS (USA)

    2010-12-15

    A storage pond dike failure occurred at the Tennessee Valley Authority Kingston Fossil Plant that resulted in the release of over 3.8 million cubic meters (5 million cubic yards) of fly ash. Approximately half of this material deposited in the main channel of the Emory River, 3.5 km upstream of the confluence of the Emory and Clinch Rivers, Tennessee, USA Remediation efforts to date have focused on targeted removal of material from the channel through hydraulic dredging, as well as mechanical excavation in some areas. The agitation of the submerged fly ash during hydraulic dredging introduces river water into the fly ash material, which could alter the redox state of metals present in the fly ash and thereby change their sorption and mobility properties. A series of extended elutriate tests were used to determine the concentration and speciation of metals released from fly ash. Results indicated that arsenic and selenium species released from the fly ash materials during elutriate preparation were redox stable over the course of 10 d, with dissolved arsenic being present as arsenate, and dissolved selenium being present as selenite. Concentrations of certain metals, such as arsenic, selenium, vanadium, and barium, increased in the elutriate waters over the 10 d study, whereas manganese concentrations decreased, likely due to oxidation and precipitation reactions.

  1. Properties of high ash char particles derived from inertinite-rich coal: 1. Chemical, structural and petrographic characteristics

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-10-15

    An investigation was undertaken to determine the properties of high ash coal-chars derived from South African discards rich in inertinites, for the development of suitable overall reaction rate models at low temperatures (<900{sup o}C). Detailed characterisation results of the parent coal and chars prepared at 700{sup o}C and 900{sup o}C obtained from standard coal analytical methods, petrographic techniques, CCSEM image analysis and a surface adsorption method are presented. The parent coal consisted of 32% by volume of inertite ('pure' inertinite), 7% of vitrite (pure 'vitrinite'), and 13% of bi- and tri-macerite, 30% of maceral/mineral mixtures (carbominerite) with 18% of mineral-rich material. Reflectances obtained from measurements taken on vitrinites and total maceral reflectance scans increased dramatically on charring at 900{sup o}C and were accompanied by an extension of vitrinite reflectance class distributions indicating higher molecular ordering. Volatiles were liberated essentially from the original parent vitrinites, creating fine gas pores. Inertinites increased in reflectance but not in porosity and were characterised as dense char fractions in the final charred product, according to a coal form analysis. Structural change due to low temperature thermal stress fracturing (passive deflagration) occurred early on in the temperature regimes, creating increased surface areas and porosity. The chars consist of a high proportion (52%) of extraneous rock fragments together with minerals mainly as fine inclusions in carbon rich particles (13%). The chars had very low porosities and surface areas. These were created by the devolatisation of reactive maceral associations and deflagration. Such materials could introduce intra-particle diffusional effects during gasification and combustion of millimetre size particles at low temperatures. 34 refs., 13 figs., 4 tabs.

  2. Application of paste technology to mitigate the dust emissions from handling of fly and bottom ash at coal fired power plant : CGTEE in Candiota, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Silva Marques, M.E. [Golder Associates Peru, Lima (Peru); Lima, H. [Golder Associates Brazil, Sao Paulo (Brazil); Mandl, B.; Francoeur, R.; Palkovits, F. [Golder Paste Technology Ltd., Mississauga, ON (Canada); Blois, R. [Companhia de Geracao Termica de Energia Electrica, Porto Alegre (Brazil)

    2010-07-01

    This paper discussed a method developed to reduce dust emissions generated in a fly ash handling procedure used at a thermal power plant located in the south of Brazil. The fly ash is collected in dry form at several locations in the plant and pneumatically conveyed to storage silos, where it is moistened with water in a mixer, loaded into dump trucks and deposited in a disposal area near a surface coal mine. The new solution created low density fly ash slurry in localized mixing tanks within the power plant. The low density slurry is pumped to an ash conditioning plant where the slurry is then mixed with the bottom ash, dewatered, and densified. The densified slurry is then pumped to an adjacent coal mine disposal site in order to be used as backfill in mined areas. The proposed method will significantly reduce dust emissions both inside and outside the plant, and will substantially reduce truck traffic at the mine. The method will reduce the environmental impacts associated with fly ash dust emissions in the region. 8 figs.

  3. Technology GRAVIMELT and possibilities of their application in preparation of Slovak brown coal

    OpenAIRE

    Machajová Zlatica; Balá? Peter; Èurillová Dana; Marchant Sharon; Turèániová ¼udmila; Hucko Richard

    1998-01-01

    The results of alkaline treatment tests on Slovak brown coal (from Nováky, Handlová and Cíge¾ localities) using the MCL procedure (Gravimelt) are presented in this paper. On the basis of conclusions of an optimal variant of the technology, the samples were pre-treated and submitted to a subsequent test at the NAOH/coal ratio = 1.0. The recovery of chemically treated coal, effectiveness of desulphurization and ash removal were assessed. This treatment procedure is less suitable for Slovak ...

  4. Status of fluid bed processing of coal in India and its potential for power generation using high ash coal

    International Nuclear Information System (INIS)

    The progress made in the last twenty years in use of fluid bed processes for power generation from coal is highly encouraging. On assessing our fuel resources we have also entered the area by putting many bubbling atmospheric pressure fluidized bed combustion (AFBC) power plants. We are yet to put up a circulating atmospheric pressure fluidized bed combustion (AFBC) power plant. A number of combined cycle power plants based on pressurised fluidized bed combustion and pressurised fluidized bed gas are being proposed and set up all over the world. Though the increased cycle efficiency of such plants is a definite advantage the unknown areas in such plants are also vast. The developments in this field are to be watched, because the efficient use of low grade coals which form a major portion of India's coal resources and the use of rejects from coal washeries for power generation is of utmost importance, of India get out of the economic and power crisis. (author). 11 figs., 1 tab

  5. Homogeneity tests and certification analyses of the IRANT coal fly ash reference material ECO by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Instrumental neutron activation analysis technique was used for homogeneity tests and certification analyses of the coal fly ash reference material ECO prepared at the Institute of Radioecology and Applied Nuclear Techniques (IRANT), Kosice, Czechoslovakia. The relative standard deviations due to inhomogeneity were found to be < 3% for 19 elements with sample weights about 50 mg. The results of determination of the elements Al,As,Ba,Ca,Ce,Co,Cr,Cs,Dy,Eu,Fe,Ga,Hf,In,K,La,Mn,Mo,Na,Nd,Ni,Rb, Sb,Sc,Sm,Sr,Ta,Th,Ti,U,V,W and Zn were compared with the IRANT certified or information values. Interference was made on the reliability of the IRANT specified values for the element contents. (author) 7 refs.; 6 tabs

  6. Qualitative and quantitative determination of various microelements in the fly ashes produced by coal burning in thermal power plants

    International Nuclear Information System (INIS)

    Two fly ash samples produced by coal burning in thermal power plants were analyzed in order to determine various microelements. The method of thermal neutron activation was used for this purpose. Well determined amounts of samples and adequate standards were prepared for irradiation. The thermal neutron activation was performed at TRIGA ICN- Pitesti reactor in the reflector zone. After activation, the samples were qualitatively and quantitatively measured by gamma spectrometry at IFIN-HH. A measuring chain containing a HPGe detector and the ACCUSPEC-A program provided by Canberra company were used. The following elements were determined: Ca, Na, Sc, K, Co, Fe, Ag, Pt, W. Their concentrations were in the range (10-6 - 50)%. (authors)

  7. Radon monitoring in coal, fly-ash, soil, water and environment of some thermal power plants in North India

    International Nuclear Information System (INIS)

    Radon (222Rn), a progeny of 238U, is a colourless, odourless but noble gas which is radioactive and poses grave health hazards, not only to uranium miners but also to the people living in normal houses and buildings and at work place in industry. Tracking its concentration, therefore, is fundamental for radiation protection strategies and mitigation. Besides, the increased interest in measuring radon concentration in environment in the vicinity of thermal power plants is due to its health hazards and environmental pollution. For experimental determination of radon, in each thermal power plant the LR-115 type- II detectors were exposed for 100 days in bare mode at different locations and also used the same for coal, fly-ash, soil and water samples collected from the thermal power plants. For comparative study, some cement samples were also collected from National Council for Cement and Building Materials (NCB), Ballabgarh (Haryana), India. The radon levels measured at some locations and in some samples are found to be high and thus pose health hazard. The radon concentration varied from 157.18 Bqm-3 to 1062.57 Bqm-3 in environment, 393.33 Bqm-3 to 2125.24 Bqm-3 in coal, 708.57 Bqm-3 to 1574.28 Bqm-3 in fly-ash, 314.83 Bqm-3 to 905.15 Bqm-3 in soil, 393.54 Bqm-3 to 1101.93 Bqm-3 in water and 157.62 Bqm-3 to 1810.48 Bqm-3-3 to 1810.48 Bqm-3 in cement, samples. (author)

  8. Phosphatidylcholine metabolism in lung microsomes and lung surfactant of rats exposed intratracheally to coal fly ash

    International Nuclear Information System (INIS)

    The effect of intratracheal administration of fly ash has been studied on lung microsomal and lung surfactant phosphatidylcholine (PC) metabolism in rats using [methyl-14C]choline and [methyl-14C]methionine. Fly-ash administration significantly increased total phospholipids, PC, phosphatidylethanolamine (PE), and phosphatidylglycerol (PG) of lung surfactant. Fly-ash administration stimulated the formation of lung microsomal PC (as measured by the incorporation of labeled precursors) both by the cytidine 5'-diphosphate (CDP)-choline pathway and by the N-methylation pathway, but this stimulation was fourfold higher in the latter case and only twofold higher in the former as compared to the control. Likewise, the secretion of PC formed by the N-methylation pathway was sixfold higher as compared to the control whereas secretion of PC formed by the CDP-choline pathway was only threefold higher as compared to the control. Fly-ash administration further increased total saturation and decreased unsaturation in PC, PE, and lysophosphatidylcholine (LPC) of lung and in PC, PE, LPC, and PG of lung surfactant as compared to the controls

  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

    The purpose of this document is to define the testing to be performed on field collected coal slurry samples by ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectroscopy). A total of 20 samples (8 from an Upper Freeport coal and 12 from an Oklahoma coal) are to be analyzed in triplicate for the elements S, Si, Al, Fe, Ca, and Mg. For each of the two coal slurry types (Upper Freeport and Oklahoma), a container of slurry labeled calibration'' has been prepared. These calibration slurries may be used to get the system tuned'' (note that the volume of the field collected slurries is relatively small and cannot be used to tune'' the system). The calibration slurries were made from the slurry collected from the drain from the second sampling stage during the field testing.

  10. Reaproveitamento de cinzas de carvão mineral na formulação de argamassas Reuse of ash coal in the formulation of mortars

    Directory of Open Access Journals (Sweden)

    J. S. Siqueira

    2012-06-01

    Full Text Available Este trabalho tem como objetivo o estudo da incorporação de cinzas provenientes da combustão do carvão mineral em caldeiras de leito fluidizado, na produção de argamassas, em substituição parcial do cimento. Foram elaborados corpos de prova utilizando-se os cimentos Portland com as especificações CPII-E-32 de características normais e areia de classificação abaixo da malha 100. Foram preparadas misturas na proporção 4 partes de agregado e 1 parte de cimento, com a inserção de cinzas nas proporções 0, 10, 20, 30, 40 e 50%. A argamassa foi desenvolvida em misturador e a moldagem foi feita em moldes de 5 cm x 10 cm. Foi analisado o comportamento de resistência à compressão após 28 dias. A resistência diminui conforme o aumento da porcentagem de cinzas. Foram feitas análises complementares de difração de raios X e constatou-se que a substituição desse resíduo pode ser feita com sucesso em argamassas com teores de até 30%.This paper aims to study the ash incorporation from the combustion of coal in fluidized bed boilers, in production of mortar, replacing part of cement. Specimens were prepared using Portland cement to the specifications CPII-E-32 of normal characteristics and classification of sand below 100 mesh. Blends in the 4:1 ratio, that is, 4 parts of aggregate to 1 part of cement, with insertion of ashes in the proportions 0, 10, 20, 30, 40 and 50%. The mortar was developed in mixing and casting was made in a mold of 5 cm x 10 cm. The behavior of compressive strength was evaluated after 28 days; the strength decreases with increasing percentage of ash. Additional analysis was carried out by X-ray diffraction, and it was found that the substitution of this waste can be successfully used in mortars with blends of up to 30%.

  11. Reaproveitamento de cinzas de carvão mineral na formulação de argamassas / Reuse of ash coal in the formulation of mortars

    Scientific Electronic Library Online (English)

    J. S., Siqueira; C. A. G., Souza; J. A. S., Souza.

    2012-06-01

    Full Text Available Este trabalho tem como objetivo o estudo da incorporação de cinzas provenientes da combustão do carvão mineral em caldeiras de leito fluidizado, na produção de argamassas, em substituição parcial do cimento. Foram elaborados corpos de prova utilizando-se os cimentos Portland com as especificações CP [...] II-E-32 de características normais e areia de classificação abaixo da malha 100. Foram preparadas misturas na proporção 4 partes de agregado e 1 parte de cimento, com a inserção de cinzas nas proporções 0, 10, 20, 30, 40 e 50%. A argamassa foi desenvolvida em misturador e a moldagem foi feita em moldes de 5 cm x 10 cm. Foi analisado o comportamento de resistência à compressão após 28 dias. A resistência diminui conforme o aumento da porcentagem de cinzas. Foram feitas análises complementares de difração de raios X e constatou-se que a substituição desse resíduo pode ser feita com sucesso em argamassas com teores de até 30%. Abstract in english This paper aims to study the ash incorporation from the combustion of coal in fluidized bed boilers, in production of mortar, replacing part of cement. Specimens were prepared using Portland cement to the specifications CPII-E-32 of normal characteristics and classification of sand below 100 mesh. B [...] lends in the 4:1 ratio, that is, 4 parts of aggregate to 1 part of cement, with insertion of ashes in the proportions 0, 10, 20, 30, 40 and 50%. The mortar was developed in mixing and casting was made in a mold of 5 cm x 10 cm. The behavior of compressive strength was evaluated after 28 days; the strength decreases with increasing percentage of ash. Additional analysis was carried out by X-ray diffraction, and it was found that the substitution of this waste can be successfully used in mortars with blends of up to 30%.

  12. Synthesis of Zeolites Na-P1 from South African Coal Fly Ash: Effect of Impeller Design and Agitation

    Directory of Open Access Journals (Sweden)

    Leslie Petrik

    2013-05-01

    Full Text Available South African fly ash has been shown to be a useful feedstock for the synthesis of some zeolites. The present study focuses on the effect of impeller design and agitation rates on the synthesis of zeolite Na-P1 which are critical to the commercialization of this product. The effects of three impeller designs (4-flat blade, Anchor and Archimedes screw impellers and three agitation speeds (150, 200 and 300 rpm were investigated using a modified previously reported synthesis conditions; 48 hours of ageing at 47 °C and static hydrothermal treatment at 140 °C for 48 hours. The experimental results demonstrated that the phase purity of zeolite Na-P1 was strongly affected by the agitation rate and the type of impeller used during the ageing step of the synthesis process. Although zeolite Na-P1 was synthesized with a space time yield (STY of 15 ± 0.4 kg d?1m?3and a product yield of 0.98±0.05 g zeolites/g fly ash for each impeller at different agitation speeds, zeolite formation was assessed to be fairly unsuccessful in some cases due the occurrence of undissolved mullite and/or the formation of impurities such as hydroxysodalite with the zeolitic product. This study also showed that a high crystalline zeolite Na-P1 can be synthesized from South African coal fly ash using a 4-flat blade impeller at an agitation rate of 200 rpm during the ageing step at 47 °C for 48 hours followed by static hydrothermal treatment at 140 °C for 48 hours.

  13. Cenizas de carbón sedimentadas: su efecto puzolánico en clinker Portland / Sedimental coal ashes: its pozzolanic effects in Portland cement clinker

    Scientific Electronic Library Online (English)

    M.A., Trezza; A.E., Crozes; A.N., Scian.

    1045-10-01

    Full Text Available Las centrales termoeléctricas generan una gran cantidad de residuos sólidos como producto de la combustión del carbón, conocidos como cenizas. Existen dos tipos de cenizas: volantes - de tamaño muy fino -, que son arrastradas por la corriente de humos de los sistemas de eliminación de partículas y, [...] - las sedimentadas - más gruesas, que se funden y se aglomeran acumulándose en el fondo del horno o en los tubos de las calderas. Intentando resolver factores técnico-económicos y ecológicos al mismo tiempo, en este trabajo presentamos los resultados obtenidos de la incorporación de un 20% en peso de cenizas sedimentadas (Cs) como adición activa al cemento Portland. Se estudia la potencial puzolanidad de la adición y se muestran resultados de seguimiento de la hidratación a temprana edad, variación de color y resistencia mecánica del material compuesto obtenido por molienda conjunta del clinker portland y el material residual. Abstract in english The power plants generate a large amount of solid waste, known as ash, as a product of combustion of coal. There are two types of ash: fly - very fine in size- which are carried by the flow of smoke removal systems, and sedimentary particles -coarse particles - which are melted and agglomerated accu [...] mulated in the bottom of the furnace or in the boiler tubes. Trying to resolve technical-economic and ecologic factors at the same time, this work presents the results of adding a 20% weight of sediment ash (Cs) as an active addition to the Portland cement. The potential pozzolanity of the addition is studied and it is shown proceeding of the hydration at early age, color variation and mechanical strength of the composite material obtained by grinding together Portland clinker with the residual material.

  14. Solidification/stabilization of electric arc furnace dust using coal fly ash. Analysis of the stabilization process.

    Science.gov (United States)

    Pereira, C F; Rodríguez-Piñero, M; Vale, J

    2001-03-30

    In this paper, the stabilization of electric arc furnace (EAF) dust containing hazardous metals such as Pb, Cd, Cr or Zn is described. The treatment involves a waste solidification/stabilization (S/S) process, using coal fly ash as the fundamental raw material and main binder. The article also contains a brief review of the most important recent publications related to the use of fly ash as S/S agents. The efficacy of the process has been evaluated mainly through leaching tests on the solidified products and compliance with some imposed leachate limits. The concentration of metals leaching from the S/S products was strongly leachate pH dependent; thus, the final pH of the leachate is the most important variable in reaching the limits and, therefore, in meeting the stabilization goals. In this study, the dependence relationship between the leachate pH and the concentrations of metals in the leachate are analyzed; in some cases, this allows us to estimate the speciation of contaminants in the S/S solids and to understand the mechanism responsible for reduced leachability of heavy metals from solidified wastes. PMID:11230914

  15. Synthesis of zeolite-P from coal fly ash derivative and its utilisation in mine-water remediation

    Directory of Open Access Journals (Sweden)

    Leslie F. Petrik

    2010-05-01

    Full Text Available Solid residues resulting from the active treatment of acid mine drainage with coal fly ash were successfully converted to zeolite-P under mild hydrothermal treatment conditions. Scanning electron microscopy showed that the zeolite-P product was highly crystalline. The product had a high cation exchange capacity (178.7 meq / 100 g and surface area (69.1 m2/g and has potential application in waste-water treatment. A mineralogical analysis of the final product identified zeolite-P, as well as mullite and quartz phases, which indicated incomplete dissolution of the fly ash feedstock during the ageing step. Further optimisation of the synthesis conditions would be required to attain complete utilisation of the feedstock. The zeolite-P was tested for decontamination potential of circumneutral mine water. High removal efficiency was observed in the first treatment, but varied for different contaminants. The synthesised zeolite-P exhibited a high efficiency for the removal of heavy metal cations, such as aluminium, iron, manganese, zinc, copper and nickel, from contaminated mine water, even with repeated use. For potassium, calcium, strontium and barium, the removal was only efficient in the first treatment and decreased rapidly with subsequent treatments, indicating preferential adsorption of the other metals. A continuous release of sodium was observed during decontamination experiments, which decreased with subsequent treatments, confirming that sodium was the main exchangeable charge-balancing cation present in the zeolite-P product.

  16. Synthesis of zeolite-P from coal fly ash derivative and its utilisation in mine-water remediation

    Scientific Electronic Library Online (English)

    Viswanath R.K., Vadapalli; Wilson M., Gitari; Annabelle, Ellendt; Leslie F., Petrik; Gillian, Balfour.

    2010-06-01

    Full Text Available Solid residues resulting from the active treatment of acid mine drainage with coal fly ash were successfully converted to zeolite-P under mild hydrothermal treatment conditions. Scanning electron microscopy showed that the zeolite-P product was highly crystalline. The product had a high cation excha [...] nge capacity (178.7 meq / 100 g) and surface area (69.1 m²/g) and has potential application in waste-water treatment. A mineralogical analysis of the final product identified zeolite-P, as well as mullite and quartz phases, which indicated incomplete dissolution of the fly ash feedstock during the ageing step. Further optimisation of the synthesis conditions would be required to attain complete utilisation of the feedstock. The zeolite-P was tested for decontamination potential of circumneutral mine water. High removal efficiency was observed in the first treatment, but varied for different contaminants. The synthesised zeolite-P exhibited a high efficiency for the removal of heavy metal cations, such as aluminium, iron, manganese, zinc, copper and nickel, from contaminated mine water, even with repeated use. For potassium, calcium, strontium and barium, the removal was only efficient in the first treatment and decreased rapidly with subsequent treatments, indicating preferential adsorption of the other metals. A continuous release of sodium was observed during decontamination experiments, which decreased with subsequent treatments, confirming that sodium was the main exchangeable charge-balancing cation present in the zeolite-P product.

  17. Self-cementitious properties of fly ashes from CFBC boilers co-firing coal and high-sulphur petroleum coke

    International Nuclear Information System (INIS)

    Self-cementitious properties of fly ash from circulating fluidized bed combustion boiler co-firing coal and high-sulphur petroleum coke (CPFA) were investigated. CPFA was self-cementitious which was affected by its fineness and chemical compositions, especially the contents of SO3 and free lime (f-CaO). Higher contents of SO3 and f-CaO were beneficial to self-cementitious strength; the self-cementitious strength increases with a decrease of its 45 ?m sieve residue. The expansive ratio of CPFA hardened paste was high because of generation of ettringite (AFt), which was influenced by its water to binder ratio (W/A), curing style and grinding of the ash. The paste cured in water had the highest expansive ratio, and grinding of CPFA was beneficial to its volume stability. The hydration products of CPFA detected by X-ray diffraction (XRD) and scanning electron microscopy (SEM) were portlandite, gypsum, AFt and hydrated calcium silicate (C-S-H)

  18. Experimental on fly ash recirculation with bottom feeding to improve the performance of a circulating fluidized bed boiler co-burning coal sludge

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Lunbo; Xu, Guiling; Liu, Daoyin; Chen, Xiaoping; Zhao, Changsui [Southeast Univ., Nanjing (China). School of Energy and Environment

    2013-07-01

    With the aim of reducing carbon content in fly ash, fly ash recirculation with bottom feeding (FARBF) technology was applied to a 75 t/h Circulating Fluidized Bed (CFB) boiler burning mixture of coal and coal sludge. And industrial experiments were carried out to investigate the influence of FARBF technology on the combustion performance and pollutant emission characteristics of the CFB boiler. Results show that as the recirculation rate of fly ash increases, the CFB dense bed temperature decreases while the furnace outlet temperature increases, and the temperature distribution in the furnace becomes uniform. Compared with the conditions without fly ash recirculation, the combustion efficiency increases from 92 to 95% when the recirculation rate increases to 8 t/h, and the desulfurization efficiency also increases significantly. As the recirculation rate increases, the emissions of NO and CO decrease, but the particulate emission increases. The present study indicates that FARBF technology can improve the combustion performance and desulfurization efficiency for the CFB boilers burning coal sludge, and this can bring large economical and environmental benefits in China.

  19. Ecological risk assessment for residual coal fly ash at Watts Bar Reservoir, Tennessee: Limited alteration of riverine-reservoir benthic invertebrate community following dredging of ash-contaminated sediment.

    Science.gov (United States)

    Buys, David J; Stojak, Amber R; Stiteler, William; Baker, Tyler F

    2015-01-01

    Benthic invertebrate communities were assessed after the December 2008 release of approximately 4.1 million m(3) coal fly ash from a disposal dredge cell at the Tennessee Valley Authority (TVA) Kingston Fossil Plant on Watts Bar Reservoir in Roane County, Tennessee, USA. Released ash filled the adjacent embayments and the main channel of the Emory River, migrating into reaches of the Emory, Clinch, and Tennessee Rivers. Dredging was completed in summer 2010, and the benthic community sampling was conducted in December 2010. This study is part of a series that supported an Ecological Risk Assessment for the Kingston site. Benthic invertebrate communities were sampled at transects spread across approximately 20 miles of river that includes both riverine and reservoirlike conditions. Community composition was assessed on a grab sample and transect basis across multiple cross-channel transects to gain an understanding of the response of the benthic community to a fly ash release of this magnitude. This assessment used invertebrate community metrics, similarity analysis, geospatial statistics, and correlations with sediment chemistry and habitat. The community composition was reflective of a reservoir system, with dominant taxa being insect larva, bivalves, and aquatic worms. Most community metric results were similar for ash-impacted areas and upstream reference areas. Variation in the benthic community was correlated more with habitat than with sediment chemistry or residual ash. Other studies have reported that a benthic community can take several years to a decade to recover from ash or ash-related constituents. Although released ash undoubtedly had some initial impacts on the benthic community in this study, the severity of these effects appears to be limited to the initial smothering of the organisms followed by a rapid response and the initial start of recovery postdredging. PMID:25158124

  20. Mineralogy and geochemistry of a superhigh-organic-sulfur coal, Yanshan Coalfield, Yunnan, China: Evidence for a volcanic ash component and influence by submarine exhalation

    Science.gov (United States)

    Dai, S.; Ren, D.; Zhou, Y.; Chou, C.-L.; Wang, X.; Zhao, L.; Zhu, X.

    2008-01-01

    The mineralogy and geochemistry of a superhigh-organic-sulfur (SHOS) coal of Late Permian age from the Yanshan Coalfield, Yunnan Province, southwestern China, have been studied using optical microscope, low-temperature ashing plus X-ray diffraction analysis, scanning electron microscope equipped with energy-dispersive X-ray spectrometer, a sequential chemical extraction procedure, and inductively coupled plasma mass spectrometry. The M9 Coal from the Yanshan Coalfield is a SHOS coal that has a total sulfur content of 10.12%-11.30% and an organic sulfur content of 8.77%-10.30%. The minerals in the coal consist mainly of high-temperature quartz, sanidine, albite, muscovite, illite, pyrite, and trace amounts of kaolinite, plagioclase, akermanite, rutile, and dawsonite. As compared with ordinary worldwide (bituminous coals and anthracite) and Chinese coals, the M9 Coal is remarkably enriched in B (268????g/g), F (841????g/g), V (567????g/g), Cr (329????g/g), Ni (73.9????g/g), Mo (204????g/g), and U (153????g/g). In addition, elements including Se (25.2????g/g), Zr (262????g/g), Nb (20.1????g/g), Cd (2.07????g/g), and Tl (2.03????g/g) are also enriched in the coal. Occurrence of high-temperature quartz, sanidine, muscovite, and illite in the M9 Coal is evidence that there is a volcanic ash component in the coal that was derived from acid volcanic ashes fallen into the swamp during peat accumulation. Occurrence of albite and dawsonite in the coal and strong enrichment of some elements, including F, S, V, Cr, Ni, Mo and U, are attributed to the influence by submarine exhalation which invaded along with seawater into the anoxic peat swamp. Abundances of lithophile elements, including rare earth elements, Nb, Y, Zr, and TiO2, indicate that the silicate minerals in the coal were derived from the northern Vietnam Upland to the south of the basin. ?? 2008 Elsevier B.V. All rights reserved.

  1. The effect of combustion conditions in a full-scale low-NO{sub x} coal fired unit on fly ash properties for its application in concrete mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Pedersen, K.H.; Jensen, A.D.; Dam-Johansen, K. [Department of Chemical and Biochemical Engineering, Technical University of Denmark, Building 229, DK-2800 Kgs. Lyngby (Denmark); Berg, M.; Olsen, L.H. [Vattenfall A/S, Nordic Generation, Thermal Power, Stoeberigade 14, DK-2450 Copenhagen SV (Denmark)

    2009-02-15

    The wide implementation of low-NO{sub x} combustion technologies in pulverized coal combustion can lead to higher levels of carbon in fly ash and increase the adsorptivity toward surfactants of the carbon. Consequently, the air entraining agent (AEA) requirements of the fly ash used for concrete production increases, which can complicate the stabilization of entrained air. In this study, a low-NO{sub x} tangential fired 875 MW{sub th} power plant burning bituminous coal have been operated under extreme conditions in order to test the impact of the operating conditions on fly ash adsorption behavior and NO{sub x} formation. It was found that the AEA adsorption of the fly ash was reduced up to five times compared to reference operation, when the plant was operated with minimum furnace air staging, three levels of burners instead of four and without recycled flue gas. The lower AEA requirements of the fly ash at these conditions were primarily caused by a reduction in total carbon content, while the AEA adsorptivity of the residual carbon was lowered to about 60% of reference value. The tested operation mode, however, increased the NO{sub x} level in the flue gas before the DeNO{sub x} plant by 60% compared to reference operation. (author)

  2. Mass and surface exhalation rates of radon in coal, fly ash, soil and water samples from thermal power plants in north India

    International Nuclear Information System (INIS)

    The combustion of coal in various thermal power plants results in the release of some natural radioactivity to the environment in the form of fly ash and bottom ash or slag due to which the radioactivity in soil, water and environment around thermal power plants increases. Radon (222Rn), a progeny of 238U, is a colourless, odourless noble gas which is radioactive and poses grave health hazards not only to uranium miners but also to the people living in normal houses, buildings and at work place in industry. Tracking its concentration therefore is important for radiation protection. The increased interest in measuring radon concentration in coal, fly ash, soil, and water in the vicinity of thermal power plants is due to its health hazards and environmental pollution. In the present study, the radioactive radon concentration in coal, fly ash, soil and water samples collected from different thermal power plants in north India has been measured using SSNTDs. The radon concentration measured in coal samples varied from 432.86±27.95 Bqm-3 to 2085.95±35.57 Bqm-3, in fly ash samples varied from 747.86±27.78 Bqm-3 to 1416.90±111.30 Bqm-3, in soil samples varied from 482.25±90.50 Bqm-3 to 688.50±84.09 Bqm-3 whereas, in water samples it varied from 15.42±1.93pCi/l to 21.80± 2.03 pCi/l. Based upon these values, the mass exhalation and surface exhalation rates have also been calculated.n rates have also been calculated. (author)

  3. Utilization of coal fly ash in construction in relation to regulations within the framework of the Dutch Soil Protection Act

    International Nuclear Information System (INIS)

    In 1987, the Dutch Government passed the Soil Protection Act. Within the framework of this act aiming at reduction of soil pollution by anthropogenic activities, a number of regulations will be enforced. One of these is the Regulation for Construction Materials, which is intended to control environmental impacts resulting from the utilization of industrial residues in construction. The regulation will apply to all conventional materials used in construction and raw materials derived from waste materials. For effective enforcement of this regulation by 1992, a full set of well documented procedures are needed to cover such aspects as sampling, storage, analysis of solids and liquids, leaching, and evaluation of test results. These procedures should ultimately be available as national (NEN), or preferably internationally (CEN, ISO), agreed standard protocols. A coherent program of projects has been started in 1990 in association with the Dutch Normalization Institute to generate these protocols and initiate the necessary research activities. As a result of the new regulations, initiatives have been taken to certify industrial residues for certain applications. The utilization of coal combustion residues in construction is governed by certificates. Thus, quality control at the utilities is an integral part of coal fly ash utilization and marketing. For public acceptance of utilization of these materials, quality control and certification is an essential element along witfication is an essential element along with demonstrations of proper performance in practice

  4. ICP-AES determination of rare earth elements in coal fly ash samples of thermal power stations: assessment of possible recovery and environmental impact of rare earth elements

    International Nuclear Information System (INIS)

    Accurate determination of rare earth elements (REEs) in ashes of thermal power plants is important in the current scenario due to its economic value, and the pollution caused if they are released in to the environment. Their toxicity to living organisms now gaining importance in international community, and some investigation shows it causes retardation in plant growth. In coal based thermal stations huge quantity of coal used annually as a fuel and lakhs of tones of waste is generated in the form of ashes. Therefore studies were carried out on three aspects - fairly rapid and accurate ICP-AES determination REEs in coal fly ash samples using addition technique, a preliminary acid leaching studies on coal received from three different fired thermal power stations using hydrochloric acid at pH 1 and 2, and quantify the REEs leached, and economic recovery of REEs using di-(2-ethylhexyl) phosphoric acid solvent extraction process or precipitation hydroxides using dilute ammonia solution. The standard addition method of REEs determination using rate and reproducible values, besides the analysis is fast compared to the ion exchange separation of REEs followed by the ICP-AES determination. (author)

  5. Production tests of a potassium chloride and coal ash based fertilizer

    Energy Technology Data Exchange (ETDEWEB)

    Unuma, H.; Takeda, S.; Sayama, S.; Itoh, S.

    1985-01-01

    Production tests are reported of a citric acid soluble potassium silicate fertilizer prepared from fly ash and KCl (an inexpensive source of potassium), with steam being used as the reaction gas. The resulting fertilizer did not meet the relevant standards, with a citric acid soluble potassium content of only about 10% and soluble silicate at about 16%. However, it has been confirmed that the use of KCl enables a citric acid soluble potassium silicate fertilizer to be produced. 3 references, 4 figures.

  6. Utilisation of different types of coal fly ash in the production of ceramic tiles

    Directory of Open Access Journals (Sweden)

    Kockal, N. U.

    2012-10-01

    Full Text Available The influence of varying proportions of different types of fly ash (used in place of feldspar and different sintering temperatures on the sintered properties of ceramic tile bodies was evaluated. The results indicated that sintering ceramic tiles with a high fly ash content at a high temperature caused a decrease in the properties because of bloating. The ceramic samples containing a higher amount of fly ash that were sintered at low temperature exhibited lower water absorption, larger shrinkage and strength because of the densification observed also in microstructural investigation.

    Se ha evaluado la influencia de la proporción de diferentes tipos de cenizas volantes (en lugar de feldespato y diferentes temperaturas de sinterización en las propiedades de soportes cerámicos. Los resultados indicaron que las composiciones con un alto contenido de cenizas volantes provocaron una disminución en las propiedades de las piczas cocidas a alta temperatura como consecuencia del hinchamiento. Las composiciones con una mayor cantidad de cenizas sinterizadas a baja temperatura mostraron una menor absorción de agua, mayor contracción y resistencia mecánica debido a la densificación como también se observó en la investigación microestructural.

  7. Investigations of the surface tension of coal ash slags under gasification conditions; Untersuchungen zur Oberflaechenspannung von Kohleschlacken unter Vergasungsbedingungen

    Energy Technology Data Exchange (ETDEWEB)

    Melchior, Tobias

    2011-10-26

    In the context of CO{sub 2}-emission-induced global warming, greenhouse gases resulting from the production of electricity in coal-fired power plants gain increasing attention. One possible way to reduce such emissions is to gasify coal instead of burning it. The corresponding process is referred to as Integrated Gasification Combined Cycle and allows for the separation of CO{sub 2} before converting a synthesis gas into electrical energy. However, further improvements in efficiency and availability of this plant technology are needed to render the alternative generation of electricity sensible from an economic point of view. One corresponding approach introduces hot gas cleaning facilities to the gasification plant which guarantee a removal of slag particles from the synthesis gas at high temperatures. The development of such filters depends on the availability of data on the material properties of the coal ash slags to be withdrawn. In this respect, the surface tension is a relevant characteristic. Currently, the surface tension of real coal ash slags as well as of synthetic model systems was measured successfully by means of the sessile drop and the maximum bubble pressure method. With regard to the sessile drop technique, those experiments were conducted in a gasification-like atmosphere at temperatures of up to 1500 C. Furthermore, the pressure inside the experimental vessel was raised to 10 bar in order to allow for deriving the influence of this variable on the surface tension. In contrast, maximum bubble pressure trials were realised at atmospheric pressure while the gas atmosphere assured inert conditions. For performing sessile drop measurements, a corresponding apparatus was set up and is described in detail in this thesis. Three computer algorithms were employed to calculate surface tensions out of the photos of sessile drops and their individual performance was evaluated. A very good agreement between two of the codes was found while the third one produces heavily scattering output. The measurement arrangement was run in an almost fully automated fashion which resulted in an immense amount of obtained surface tension data. Maximum bubble pressure experiments were conducted at the University of Osaka, Japan, on selected real ash samples. Due to a far longer time required for determining bubble pressures in comparison to taking drop pictures, only a small number of temperatures could be studied abroad. The results show the surface tension to be in the range from 200 mN/m to 500 mN/m which is in accordance with data taken from the literature. While three discrete temperature intervals of particular slag behaviour could be identified in sessile drop experiments, results of maximum bubble pressure trials suggest the surface tension to be lower under inert conditions compared to a reducing atmosphere. The outcomes generated in Japan additionally show a better agreement to surface tensions forecasted by model calculations. Fe{sub 2}O{sub 3} being considered to have a pronounced influence on slag characteristics is made responsible for such observations. As soon as pressure is applied, the surface tension is found to decrease significantly. In order to visualise the data obtained by means of the sessile drop technique, regression functions were employed that can be implemented into future design calculations on hot gas cleaning facilities. (orig.)

  8. Composition and morphology of fly ash from fluidized bed combustion of brown coal.

    Czech Academy of Sciences Publication Activity Database

    Sýkorová, Ivana; Smolík, Ji?í; Schwarz, Jaroslav; Kerkkonen, O.; Ku?era, Jan; Havránek, Vladimír

    Essen : P+W Druck und Verlag GmbH, Essen Germany Deutsche Wissenschaftliche Gesellschaft für Erdöl und Kohle, 1997 - (Ziegler, A.; Heek, K.; Klein, J.; Wanzl, W.), s. 1187-1190 ISBN 3-931850-22-6. [International Conference on Coal Science /9./. Essen (DE), 07.09.1997-12.09.1997] R&D Projects: GA ?R GA104/95/0653

  9. Environmental impact of coal ash on tributary streams and nearshore waters of Lake Erie. Quarterly reports, August 31 and November 30, 1975, combined. [Cd, Zn, Cu, Fe, Mn, Cr, Ca, K, Mg, Na, Pb, As, Se

    Energy Technology Data Exchange (ETDEWEB)

    1975-01-01

    The study of coal wastes in Chautauga County, New York was begun on June 1, 1975. The major effort to date has been made on the fly ash dump west of Dunkirk, N.Y. The following topics are covered: description of the site; invertebrate biology; selection of trace elements for study and methods of analysis; water analyses; analyses of invertebrates; literature search; physical chemistry of coal ash and the leaching process; and study of lake sediments.

  10. Coal Research

    Science.gov (United States)

    1986-01-01

    Coal slurries are "clean" pulverized coal mixed with oil or water. Significant fuel savings can be realized when using coal slurries. Advanced Fuels Technology (AFT) utilized a COSMIC program, (Calculation of Complex Chemical Equilibrium Compositions), which provides specific capabilities for determining combustion products. The company has developed a cleaning process that removes much of the mineral sulphur and ash from the coals.

  11. Synthesis and characterization of zeolite material from coal ashes modified by surfactant; Sintese e caracterizacao de material zeolitico de cinzas de carvao modificado por surfactante

    Energy Technology Data Exchange (ETDEWEB)

    Fungaro, D.A., E-mail: dfungaro@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (CQMA/IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Quimica e Meio Ambiente; Borrely, S.I. [Instituto de Pesquisas Energeticas e Nucleares (CTR/IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Tecnologia das Radiacoes

    2010-07-01

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

  12. Natural rain - induced element leaching from coal ASH; La pluie naturelle - lixiviation d'element de la cendre de charbon

    Energy Technology Data Exchange (ETDEWEB)

    Popovic, A.; Djordjevic, D.; Polic, P. [Belgrade Univ., Dept. of Chemistry, IChTM, Chemistry Center, Belgrade (Yugoslavia)

    2000-07-01

    Six composite samples of coal ash from power plants 'Nikola Tesla' A and B, located in the vicinity of Obrenovac, near Belgrade (Yugoslavia), were subjected to extraction with 1 M acetate solution, pH 5.5, in order to imitate possible leaching of the ash by natural acidic rain. Seven trace and five major elements have been examined, and the obtained amounts were in the range from 0.003 {+-} 0.001 ppm (Cd), to 117 {+-} 27 ppm (Ca), dry ash basis. Though some of the concentrations were higher than allowed by domestic and international regulations it can be concluded that neither of the examined elements represents a serious threat for the environment (at least for the conditions applied in this experiment). Also, both magnesium and iron are carriers of copper, chromium and arsenic, while cadmium is associated with magnesium and manganese. Calcium and manganese are beside magnesium and iron, scavengers of arsenic. (authors)

  13. On the use of electrical resistivity methods in monitoring infiltration of salt fluxes in dry coal ash dumps in Mpumalanga, South Africa

    Scientific Electronic Library Online (English)

    Innocent, Muchingami; Jacobus, Nel; Yongxin, Xu; Gideon, Steyl; Kelley, Reynolds.

    Full Text Available One of the principal environmental concerns relating to coal combustion waste disposal is the potential for groundwater contamination from salt fluxes and trace elements that may be leached into the underlying groundwater system. Since changes in moisture and salt concentrations usually provide cont [...] rasts in electrical properties against the host media, electrical resistivity methods can be used to monitor ingression of solute plumes as well as to detect any preferential flow paths within the ash medium. In this study, 2D electrical resistivity tomography was used to monitor brine (10% NaCl) water ingression through the unsaturated zone of a dry coal ash dump at a power station, Mpumalanga, South Africa. This was after the initial laboratory determination of the relation between electrical resistivity and moisture/salt content for the ash dump. The results showed that infiltration plume progression was more pronounced in the vertical direction, suggesting that moisture movement is mainly due to gravitational pull. There was no evidence of preferential flow within the ash medium, although the different infiltration rates for different sites suggested different permeability within the unsaturated zone.

  14. Best management practices plan for the Chestnut Ridge-Filled Coal Ash Pond at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    The Chestnut Ridge Filled Coal Ash Pond (FCAP) Project has been established to satisfy Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) requirements for the Chestnut Ridge Operable Unit 2. FCAP is on Chestnut Ridge, approximately 0.5 miles south of the Y-12 Plant. A 62-foot high earthen dam across Upper McCoy Branch was constructed in 1955 to create a pond to serve as a settling basin for fly and bottom ashes generated by burning coal at the Y-12 Steam Plant. Ash from the steam was mixed with water to form a slurry and then pumped to the crest of Chestnut Ridge and released through a large pipe to flow across the Sluice Channel area and into the pond. The ash slurry eventually overtopped the dam and flowed along Upper McCoy Branch to Rogers Quarry. The purpose of this document is to provide a site-specific Best Management Practices (BMP) Plan for construction associated with environmental restoration activities at the FCAP Site

  15. Zeolite A synthesis employing a brazilian coal ash as the silicon and aluminum source and its applications in adsorption and pigment formulation