WorldWideScience
1

Biological activity of coal alkaline ashes  

Energy Technology Data Exchange (ETDEWEB)

This paper discusses the results of tests of the biological activity of ashes produced by combustion of brown coals in the Konin power station and black coal in the Halemba power station. Possibility of agricultural use of ash from ash spoil banks of the power stations is analyzed. Mustard plant (sinapis alba) was sown in ash samples. Plant growth was observed as well as quantitative and qualitative growth of bacteria in the soil. The tests show that the biological activity of alkaline ashes is generally low. The biological activity of brown coal ash is higher than that of black coal ash. Addition of peat increases the biological activity of ash. Green manure can both negatively and positively influence the biological activity of ash: in the case of ashes from Konin the influence is negative, and in the case of Halemba ash the influence is positive. Adding soil rich in organic matter is superior to adding peat or green manure. On the basis of tests recommendations are formulated on using power station ash with the aim of reducing the negative environmental effect of ash spoil banks. (3 refs.) (In Polish)

Krezel, Z.; Krezel, R.; Wysocki, W.

1978-01-01

2

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

Science.gov (United States)

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

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

2012-08-01

3

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

International Nuclear Information System (INIS)

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

4

Alkaline coal fly ash amendments are recommended for improving rice-peanut crops  

Energy Technology Data Exchange (ETDEWEB)

A field experiment investigating amendments of organic material including farmyard manure, paper factory sludge and crop residues combined with fly ash, lime and chemical fertilizer in a rice-peanut cropping system was conducted during 1997-98 and 1998-99 at the Indian Institute of Technology, Kharagpur, India. The soil was an acid lateritic (Halustaf) sandy loam. For rice, an N:P:K level of 90:26.2:33.3 kg/ha was supplied through the organic materials and chemical fertilizer to all the treatments except control and fly ash alone. The required quantities of organic materials were added to supply 30 kg N/ha and the balance amount of N, P and K was supplied through chemical fertilizer. Amendment materials as per fertilization treatments were incorporated to individual plots 15 days before planting of rice during the rainy season. The residual effects were studied on the following peanut crop with application of N:P:K at 30:26.2:33.3 kg/ha through chemical fertilizer alone in all treatments, apart from the control. An application of fly ash at 10 t/ha in combination with chemical fertilizer and organic materials increased the grain yield of rice by 11% compared to chemical fertilizer alone. The residual effect of both lime and fly ash applications combined with direct application of chemical fertilizer increased peanut yields by 30% and 24%, respectively, compared to chemical fertilizer alone. Treatments with fly ash or lime increased P and K uptake in both the crops and oil content in peanut kernel compared to those without the amendments. Alkaline coal fly ash proved to be a better amendment than lime for improving productivity of an acid lateritic soil and enriching the soil with P and K.

Swain, D.K.; Ghosh, B.C. [Agricultural and Food Engineering Department, Indi an Inst. of Technology, Kharagpur, West Bengal (India); Rautaray, S.K. [RRLRRS, Gerua Via-Hajo, Dist-Kamrup, Assam (India)

2007-05-15

5

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.

6

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

International Nuclear Information System (INIS)

The disposal of coal combustion residues (CCR) has led to a significant consumption of land in the West Balkan region. In Tuzla (Bosnia and Herzegovina) we studied previously soil-covered (farmed) and barren CCR landfills including management practises, field ageing of CCR and the transfer of trace elements into crops, wild plants and wastewaters. Soil tillage resulted in mixing of cover soil with CCR. Medicago sativa showed very low Cu:Mo ratios (1.25) which may cause hypocuprosis in ruminants. Total loads of inorganic pollutants in the CCR transport water, but not pH (?12), were below regulatory limits of most EU countries. Arsenic concentrations in CCR transport water were -1 whereas reductive conditions in an abandoned landfill significantly enhanced concentrations in leachates (44 ?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

7

Identifying mechanisms for the mobilization and attenuation of elemental constituents from weathered alkaline coal ash using geochemical modeling  

OpenAIRE

Nearly 70% of coal combustion products (CCPs) produced annually in the United States (110 million tons in 2001) are disposed of in saturated ash impoundments or ash landfills. The large volume of disposed CCPs and their potential to leach toxic trace metals (e.g., As, Se, Hg, Pb, and Cr) at concentrations above established groundwater quality standards is a major concern. A large amount of empirical data is available pertaining to the effects of CCPs on water quality; however, only relatively...

Burns, Perre Edmon

2003-01-01

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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.

9

Measuring ash content of coal  

International Nuclear Information System (INIS)

An apparatus for measuring the ash content of coal is claimed. It comprises a means for irradiating a known quantity of coal in a transport container with a known dose of neutrons, a means for detecting ?-rays having a predetermined energy emitted by the irradiated coal, the ?-rays being indicative of the presence of an ash-forming element in the coal, a means for producing a signal related to the intensity of the ?-ray emission and a means responsive to the signal to provide an indication of the concentration of the ash-forming element in the coal

10

Coal ash utilization in Japan  

Energy Technology Data Exchange (ETDEWEB)

Japan is one of the major coal-importing countries in the world, importing more than 100 types of coal every year, with some of the electric power plants using as many as 20 types of coal per year. The major sources are Australia, U.S., China, and Indonesia. Japan's dependency on coal is expected to keep the same level in future, under to diversify energy resources in our country. In order to use the coal stably, it is important to expand effective utilization of coal as well as to use coal cleanly and effectively. JCOAL investigates the data of coal ash production & utilization every year. In 2003 fiscal year, about 9.9 million tons of coal ash was produced in coal combustion, of which 85% was effectively used and the rest was disposed. The utilization rate of cement raw material (alternative for clay) is 70% and cement/concrete admixture 5%, civil engineering field 10%, and construction field 5%, agriculture field 2%, others 8%. Using the coal ash as a cement raw material has little room for increasing the amount any further, therefore it is required to expand the effective utilization in cement admixture or in the civil engineering field. This paper describes the situation of coal ash production and the trend of utilization in Japan.

Yuko Yamazaki; Yoshiaki Sakai; Akemitsu Akimoto; Atsushi Kobari [Japan Coal Energy Center, Tokyo (Japan)

2005-07-01

11

Leaching characteristics of coal ash  

International Nuclear Information System (INIS)

In the thermal power station producing coal ash, the present trend is to dispose of fly and bottom ash in wet slurry form to a nearby ash pond site in which the ash settles and clear water is allowed to overflow from the ash pond. By virtue of the leaching characteristics of the ash, the heavy metals contained in the ash may gradually and slowly get leached from the ash and percolate to the nearby water bodies such as tube wells, ground waters, etc. In order to study the leaching characteristics of ash, experiments have been conducted in the laboratory by column and batch tests to study short, medium and long term leaching behaviour. The paper discusses the methodology adopted and gives the results obtained for different liquid-solid ratios by column and cascading methods including interpretation of the data. (author). 15 refs., 11 figs

12

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

OpenAIRE

Coal serves as the primary energy source in most parts of the world. It is a fact that coal combustion yields enormous quantities of fly ash some of which are either hydraulically placed or dry dumped. The current study attempts to provide a comprehensive characterisation of a disused alkaline fine coal ash dam (FCAD) towards assessing environmental impact, rehabilitation and utilisation potential. Fine coal ash refers to a combination of approximately 83% power station fly ash and 17% gas...

Mahlaba, Jabulani Samuel; Kearsley, Elsabe P.; Kruger, Richard A.

2011-01-01

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

OpenAIRE

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

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

2013-01-01

14

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

15

Sorption of aqueous phosphorus onto bituminous and lignitous coal ashes  

International Nuclear Information System (INIS)

Aiming at the development of a phosphorus removal technology for waste water, phosphate (PO43-) retention behavior of bituminous and lignitous coal ashes was investigated using a batch reactor. Ash samples, including fresh and weathered fly and bottom ashes, were studied for their sorption isotherms and reversibility. Fly ashes had a much higher phosphate retention capacity (4000-30,000 mg P/kg) than bottom ashes (15-600 mg P/kg). Lignitous coal ashes were more capable of retaining phosphate than bituminous coal ashes. The retention process was largely irreversible, and the irreversibility increased with the increase in the retention capacity. Weathering enlarged the retention capacity of the bituminous bottom ash, but substantially lowered that of the fly ash, likely due to the difference in the weather-induced changes between the fly and bottom ashes. Sorption isotherms of fly ashes were found to be adequately represented by the Langmuir model while those of bottom ashes fitted better to the Freundlich model. Concentrations of Ca2+ and PO43- in the aqueous phase were measured at the end of sorption and desorption experiments, and were compared with solubilities of three calcium phosphate minerals. The aqueous solutions were saturated or super-saturated with respect to tricalcium phosphate (Ca3(PO4)2) and hydroxyapatite (Ca5(PO4)3OH), and slightly sub>4)3OH), and slightly under-saturated with respect to amorphous calcium phosphate. It is concluded that precipitation of calcium phosphate is the predominant mechanism for phosphate retention by coal ash under the conditions studied. There is a strong and positive correlation between alkalinity and phosphate sorption capacity. Consequently, acid neutralization capacity (ANC) can be used as an indicator of phosphate sorption capacity of coal ashes

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Sorption of aqueous phosphorus onto bituminous and lignitous coal ashes  

Energy Technology Data Exchange (ETDEWEB)

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

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

2007-09-05

17

Coal ash artificial reef demonstration  

International Nuclear Information System (INIS)

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

18

Call for tighter coal ash disposal standards  

Science.gov (United States)

More than 200 million tons of coal ash and scrubber sludge were deposited from coal plants into ponds or landfills between 2009 and 2011, according to a 21 December report by the Environmental Integrity Project (EIP), a nonprofit organization based in Washington, D. C. EIP issued the report to mark the fourth anniversary of the dike rupture at the Tennessee Valley Authority's Kingston Fossil Plant, which spilled an estimated 1.1 billion gallons of coal fly ash slurry into the Tennessee River system on 22 December 2008. EIP called for the U.S. Environmental Protection Agency (EPA) to issue ash disposal standards.

Showstack, Randy

2013-01-01

19

Coal and fly ash-problem  

International Nuclear Information System (INIS)

Indian thermal power plants use coal carrying as high as 30 to 40% of ash. As larger and larger amounts of coal are going to be used to meet the increasing demand for electrical energy, large amount of fly ash is bound to be produced as solid waste. Its disposal gives rise to adverse environmental impacts such as contamination of surface and subsurface water with toxic heavy metals which are constituents of coal, loss of soil fertility around plant sites and siltation of natural drainage system. For large scale utilization of ash in a proper manner, it is necessary to study physico-chemical properties of ash, mineralogy of coal used in power plants and size distribution of ash grains. Dependence of physico-chemical properties of ash on mineral constituents of coal and mechanism of burning is discussed. Enrichment of toxic metals in ash and presence of halogens in Indian coal and their likely environmental impacts are also pointed out. (M.G.B.). 17 refs., 5 tabs., 3 figs

20

Elemental analysis of coal and coal ASH by PIXE technique  

International Nuclear Information System (INIS)

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: ? Elemental analysis of coal and coal ash including pond ash is the first of its kind. ? The enrichment ratio has been exclusively explained in the study. ? Non-destructive PIXE analysis has been employed in this study and both major and trace elements has been estimated.

21

Measurement of the ash content of coal  

International Nuclear Information System (INIS)

A monitor for determining the ash content of coal in wagons consisting of a structure including means for irradiating each wagon as it passes the structure with a known dose of neutrons, means for detecting and measuring the intensities of ?-rays emitted by ash-forming elements in the coal, and means for providing as indication of the concentration of the ash-forming elements. There also are included interlocks for ensuring that the neutron source is only operated when a loaded wagon is in the appropiate position

22

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

Science.gov (United States)

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

23

Mutagenicity and genotoxicity of coal fly ash water leachate.  

Science.gov (United States)

Fly ash is a by-product of coal-fired electricity generation plants. The prevalent practice of disposal is as slurry of ash and water to storage or ash ponds located near power stations. This has lain to waste thousands of hectares of land all over the world. Since leaching is often the cause of off-site contamination and pathway of introduction into the human environment, a study on the genotoxic effects of fly ash leachate is essential. Leachate prepared from the fly ash sample was analyzed for metal content, and tested for mutagenicity and genotoxicity. Analyses of metals show predominance of the metals-sodium, silicon, potassium, calcium, magnesium, iron, manganese, zinc, and sulphate. The Ames Salmonella mutagenicity assay, a short-term bacterial reverse mutation assay, was conducted on two-tester strains of Salmonella typhimurium strains TA97a and TA102. For genotoxicity, the alkaline version of comet assay on fly ash leachate was carried in vitro on human blood cells and in vivo on Nicotiana plants. The leachate was directly mutagenic and induced significant (Pfly ash dumpsites has the genotoxic potential and may lead to adverse effects on vegetation and on the health of exposed human populations. PMID:18995907

Chakraborty, Rajarshi; Mukherjee, Anita

2009-03-01

24

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

25

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

International Nuclear Information System (INIS)

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

26

HEAT TRANSFER THROUGH COAL ASH DEPOSITS  

OpenAIRE

Experiments have been performed in a facility designed for steady state heat transfer through coal ash deposits obtained from utility boilers. A one-dimensional heat flux through the ash deposits was achieved by subjecting one surface to intense irradiation from SiC electrodes and the other surface to allow temperature heat sink. Temperature profiles and "effective" thermal conductivities (k(,e)), which account for both conduction and radiation heat transfer, were measured over a wide range o...

Anderson, D. W.

1985-01-01

27

Sensing the ash content of coal  

International Nuclear Information System (INIS)

The ash content of a coal sample is sensed by bombarding it with primary radiation comprising at least two spectrums of energies (46 KeV and 9-17 KeV ? and X-rays) to cause radiative reactions in the coal, sensing the secondary radiation generated by the radiative reactions caused by one of the two spectrums of energies (46 KeV), sensing the secondary radiations at a characteristic fluorescent energy of at least one element (e.g. iron) in the coal sample, the characteristic fluorescent energy being excited by the other of the two spectrums of energies (9-17 KeV), and using the sensed secondary radiations to determine the ash content of the coal. The ? and X-rays may come from a single lead 210 source or from separate sources. (author)

28

Synthesis of zeolites from coal fly ash  

OpenAIRE

The combustion of coal in power stations produces large quantities of coal fly ash (CFA). At present, in the Netherlands, this combustion residue is almost completely used for the production of bUilding materials. Expectations that the present use of CFA would be affected in the near future by legal and technical developments and by competition with other residual materials, started an interest in new possible applications. One of these is the synthesis of zeolites, the subject...

Hollman, G. G.

1999-01-01

29

Acid leaching of coal and coal-ashes  

Energy Technology Data Exchange (ETDEWEB)

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

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

2003-10-01

30

Development of the ash-free coal (Hyper-coal) process: characteristics of the remaining ash  

Energy Technology Data Exchange (ETDEWEB)

Hyper-coal is an ash free (< 200 PPM) and alkali reduced (Na+K<0.5 PPM) coal, which can be directly fired in the high efficiency gas turbine generation system (1350{sup o}C type). A 0.1t/d bench-scale unit is now under construction in the Takasago Works of KOBE Steel Ltd., Hyogo, Japan, and the operation will be started on December 2003. The Hyper-coal sample was produced in a semi-continuous apparatus, which has 30 L of extraction vessel. Several hundred PPM of ash remained in the filtered HPC. This paper focuses the characteristics of such remaining ash. The metallic element component in Hyper-coal is largely different from the raw coal; Fe, Si and Ti occupy the majority in the remaining ash. The existence of organic metals such as siloxanes is confirmed, but the quantity is negligible. A TEM image indicates that the Hyper-coal ash is formed by nano-meter particles. XRD or XPS analysis cannot detect since the crystalline structure is too small. Rich domains of Si, Al, Ca and O appeared on the surface of a Hyper-coal in the SEM-EDX images. It is considered that most of the remaining ash may be the ultra fine particles which are too small to be filtered (pore size; 0.5 {mu}m), and dispersed in the solution. Aggregated metallic compounds may be formed when the solvent is removed by distillation by concentrating the solution. On the other hand, such a rich domain does not appear on Hyper-coal particle when a flasher removes the solvent. This suggests that the organic solids (Hyper-coal) and metallic compounds (ash) are formed separately in the flasher. 4 refs., 8 figs., 4 tabs.

Noriyuki Okuyama; Nobuyuki Komatsu; Takuo Shigehisa; Takao Kaneko [Kobe Steel, Ltd. (Japan)

2003-07-01

31

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-07-15

32

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2009-07-01

33

Element bioaccumulation from coal fly ash  

International Nuclear Information System (INIS)

The hazard associated with exposure of populations to fossil-fuel combustion effluents has long been recognized. In this paper, work that was performed in an attempt to study the fate of various elements contained in coal fly ash after the exposure of ash to laboratory rats is described. Experiments were designed to examine relationships among exposure route, mass of exposure dose, and the rate and level of element accumulation in various body organs. Ash doses of 50 and 100 mg and 50, 100, and 200 mg were administered intratracheally and intragastrically, respectively, to female laboratory rats. Samples were pooled according to dose mass and administration route for each sacrifice day in groups of three rats. These samples were then analyzed using instrumental neutron activation analysis

34

Coal Ash Corrosion Resistant Materials Testing  

Energy Technology Data Exchange (ETDEWEB)

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.

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

2003-08-31

35

Surface modification of coal fly ash by sodium lauryl sulphate  

OpenAIRE

Thirty million tons of coal fly ash are produced each year in South Africa of which approximately 5% is utilised beneficially. With the growing concern about pollution and increasing landfill costs, the study of the utilisation and application of coal fly ash has increased worldwide. The morphology and particle size of fly ash make it suitable for application as filler in polymers, but its application is hindered by the lack of compatibility between the inorganic surface of the ash and...

Mathebula, Confidence Lethabo

2013-01-01

36

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

Science.gov (United States)

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

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

2007-01-31

37

Metal release and speciation changes during wet aging of coal fly ashes.  

Science.gov (United States)

Introduction of coal fly ash into aquatic systems poses a potential environmental hazard because of its heavy metal content. Here we investigate the relationship between solid phase transformations, fluid composition, and metal release and speciation during prolonged wet aging of a class C and class F coal fly ash. The class C ash causes rapid alkalinization of water that is neutralized over time by CO(2) uptake from air and calcite precipitation. The resulting aqueous metal concentrations are below regulatory limits with the exception of Cr; solubility constraints suggest this is released as chromate. Limited As release is accompanied by no change in solid-phase speciation, but up to 35% of the Zn in the ash dissolves and reprecipitates in secondary phases. Similar processes inhibit Ba and Cu release. In contrast, the class F ash causes rapid acidification of water and initially releases substantial quantities of As, Se, Cr, Cu, Zn, and Ba. Arsenic concentrations decline during aging because of adsorption to the iron oxide-rich ash; this is aided by As(III) oxidation. Precipitation processes lower Ba and Cr concentrations during aging. Se, Cu, and Zn concentrations remain elevated during wet aging and solid-phase Zn speciation is not affected by ash-water reactions. Total metal contents were poor predictors of metal release, which is predominantly controlled by metal speciation and the effects of ash-water reactions on fluid pH. While contact with atmospheric gases has little effect on class F ash, carbonation of class C ash inhibits metal release and neutralizes the alkalinity produced by the ash. PMID:23035817

Catalano, Jeffrey G; Huhmann, Brittany L; Luo, Yun; Mitnick, Elizabeth H; Slavney, Adam; Giammar, Daniel E

2012-11-01

38

Ash transformation during co-firing coal and straw  

DEFF Research Database (Denmark)

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.

Zheng, Yuanjing; Jensen, Peter Arendt

2007-01-01

39

Strontium isotopic characterization of soils and coal ashes  

International Nuclear Information System (INIS)

The 87Sr/86Sr isotopic ratios and Rb and Sr concentrations were measured for a number of soils and samples of coal-derived fly and bottom ashes. Fly and bottom ashes from a given coal rank are similar in their concentrations of Rb and Sr and their 87Sr/86Sr ratios. Values of 87Sr/86Sr isotopic ratios of ashes decrease in the order bituminous > subbituminous > lignitic, reflecting the decreasing rank of parent coals. The 87Sr/86Sr isotopic ratios of soils vary widely, differing significantly only from the ratios observed for lignitic ashes. The results indicate that the 87Sr/86Sr values may be used as a tracer for detecting dispersion of lignitic ashes on soils. In these coal ashes, the 87Sr/86Sr ratios of the biogeologically available fraction of Sr are linearly correlated with the logarithm of the Sr concentrations, the logarithm of the Rb/Sr ratios, and the Rb concentrations. (author)

40

Investigations on Cr mobility from coal fly ash  

Energy Technology Data Exchange (ETDEWEB)

Coal fly ash, which is a source of metals emission to environment, was researched. Investigations on Cr chemical fractions and their environmental mobility in ash-solution system were carried out. In order to obtain results repeatedly, the conditions of sequential extraction of Cr from coal fly ash were optimized. It was found that Cr in coal fly ash occurs in the following fractions (mg kg{sup -1}): exchangeable (2.5), associated to carbonates (4.0), associated to organic matter and sulfides (8.5), associated to Fe-Mn oxides (16.0), and residual (41.6). Mobility fractions of Cr contain 8.2% of its total concentration in the fly ash in environmental conditions. The obtained results indicate that coal fly ash is a source of environmental contamination by Cr especially in soils where its utilization is inadequate. 24 refs., 2 figs., 6 tabs.

Eleonora Soco; Jan Kalembkiewicz [Rzeszow University of Technology, Rzeszow (Poland). Department of Inorganic and Analytical Chemistry

2009-08-15

41

ULTRAFINE ASH AEROSOLS FROM COAL COMBUSTION: CHARACTERIZATION AND HEALTH EFFECTS  

Science.gov (United States)

Ultrafine coal fly ash particles, defined here as those with diameters less than 0.5 micrometer, typically comprise less than 1% of the total fly ash mass. These particles are formed almost exclusively through ash vaporization, nucleation, and coagulation/condensation mechanisms,...

42

The potential of biological sludge amended combustion coal ash residues as artificial plant growth media : a laboratory column study to assess the influence of weathering on elemental release  

OpenAIRE

Sasol biological sludge, coal fine and gasification ash were the three waste streams involved in this study. The main concern is that on their own they are not suitable as growth mediums, the ash is alkaline (pH>12) with high salinity (total dissolved solids of 8000 mg ?-1). Fine ash is microporous (particle size diameter <250 ?m) and forms cemented layers that can restrict root growth while, gasification ash in macroporous (most particle size diameter ranged between 1 and 75 mm...

Sukati, Bonokwakhe Hezekiel

2012-01-01

43

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

Science.gov (United States)

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

Su, Tingzhi; Wang, Jianmin

2011-11-01

44

Characterization and environmental evaluation of Atikokan coal fly ash for environmental applications  

Energy Technology Data Exchange (ETDEWEB)

Coal fly ash from thermal power generating stations has become a valuable byproduct in various commercial and environmental applications due to its cementitious, alkaline, and pozzolanic properties. It is used as a raw material in cement production, and also as a replacement for cement in concrete production. This study provided physical, chemical, and mineralogical characterizations of fresh and landfilled coal fly ash from a thermal generation station in Ontario. Fly ash behaviour under various environmental conditions was examined. Tests were conducted to characterize fly ash acid neutralization capacity and heavy metal sorption capacity. The study showed that fresh and landfilled fly ash samples showed significant variations in morphology, mineralogy, and chemical composition. X-ray diffraction studies demonstrated that weathering of the fly ash caused the formation of secondary minerals. The study also showed that the heavy metals from both fresh and landfilled fly ash samples were below leachate criteria set by the provincial government. It was concluded that both fresh and landfilled fly ash are suitable for various environmental and engineering applications. 55 refs., 5 tabs., 11 figs.

Yeheyis, M.B.; Shang, J.Q.; Yanful, E.K. [Western Ontario Univ., London, ON (Canada). Dept. of Civil and Environmental Engineering

2008-09-15

45

Identification and quantification of radionuclides in coal ash. Final report  

International Nuclear Information System (INIS)

One of the important environmental issues raised recently in regard to coal ash reuse for highway construction purposes (e.g., embankment development) is that of worker, and public, exposure to radiation which might possibly be emitted by these types of residues. This research project subsequently addressed the associated issue of radiation emission by coal ash residuals generated within the State of Indiana, covering both fly ash and bottom ash materials. Samples were obtained at sixteen different coal-fired power generating facilities within Indiana and subjected to quantitative analysis of their associated gamma-ray emission levels. After identifying the responsible radionuclides, a conservative approximation was then developed for the worst-case potential occupational exposure with construction employees working on this type of high-volume, coal ash embankment. In turn, these potential emissions levels were compared to those of other traditional construction materials and other common sources

46

Natural radioactivity level in coal and ash collected from Baoji coal-fired power plant  

International Nuclear Information System (INIS)

Specific activities of natural radionuclides 226Ra, 232Th and 40K were assessed in coal (3 samples), fly ash (17 samples) and bottom ash (6 samples) collected from Baoji coal-fired power plant. This paper analyzed the characteristics of 226Ra, 232Th and 40K contents in bottom ash and fly ash, and studied the concentration factors of these radionuclides in ash in relation to those in coal. The level of natural radionuclides 226Ra, 232Th and 40K of coal collected from Baoji coal-fired power plant are in the range of radionuclides contents of Chinese coal. The natural radioactivity level of fly ash collected from Baoji coal-fired power plant is close to Beijing and Shanghai coal-fired power plants. The paper farther assessed the possibility of fly ash of Baoji coal-fired power plant used as building materials according to the state standard. The results show that there are 29% samples exceeding the state limit when fly ash used as building materials. So the usage of fly ash in building material should be controlled. (authors)

47

Supplying Fe from molten coal ash to revive kelp community  

Energy Technology Data Exchange (ETDEWEB)

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

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

2006-02-15

48

Submicron ash formation from vaporization of minerals in coal  

Energy Technology Data Exchange (ETDEWEB)

In recent years, fine particles have been correlated with various harmful effects on health, and many countries have imposed restrictions on emission of these particles/ambient standards. Fine ash particles are formed during coal combustion in power stations and a small proportion elude air pollution control devices to be emitted into the atmosphere. This material has come under considerable scrutiny in recent years. Previous studies have shown that combustion of coals of different rank can result in differences in the amount and chemistry of the submicron ash particles. However, only a limited number of laboratory studies have sought to determine the amount and composition of submicron ash formed from the combustion of different coals of similar rank. This study compares the submicron ashes formed from five bituminous Australian coals of similar rank. The five coals were burned in a laminar flow drop tube furnace in two different oxygen environments to determine the amount and composition of submicron ash formed. The experimental setup and ash analysis techniques are described and the repeatability of the experiments is discussed. The variability in the submicron ash yield and the submicron ash composition are presented and discussed. 21 refs., 4 figs., 5 tabs.

B.J.P. Buhre; J.T. Hinkley; R.P. Gupta; T.F. Wall; P.F. Nelson [University of Newcastle (Australia). Cooperative Research Centre for Coal in Sustainable Development, Chemical Engineering Department

2003-07-01

49

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2005-08-01

50

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)

51

Mössbauer Studies of Thermal Power Plant Coal and Fly Ash  

Science.gov (United States)

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

Taneja, S. P.

52

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.

53

? 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.)

54

Determination of ash-forming elements in lignite coal  

International Nuclear Information System (INIS)

The most important methods are discussed suitable for the determination of ash-forming elements in coal. In this connection questions of the concentrations of elements in lignites, of the sample preparation, and of the selection of methods for the determination of ash-forming elements are addressed. Advantages and disadvantages of different analysis techniques are shown using concrete examples. (author)

55

Chemical Changes During Pelletising of Brown Coal Ash  

International Nuclear Information System (INIS)

Investigation has been made of the pelletising properties of ash from the combustion of three Victorian brown coals. The Moessbauer spectra showed that the pozzolanic reaction of the calcium aluminoferrite to form ferrihydrite and hydrogarnet was the principal determinant of the pellet strength and ash without this phase did not form strong pellets.

56

Determination of ash, moisture and specific energy of coal  

International Nuclear Information System (INIS)

On-line ash gauges based on the pair production (PP) technique are in routine use on high-throughput sample by-lines in the Australian coal industry. Root mean square differences between PP gauge ash and chemical assay ash are in the range 0.21 to 0.34 wt% ash for on-line measurements on coal of up to 20 wt% ash. The PP technique is about a factor of 4 less sensitive to variations in ash composition than the alternative lower-energy ?-ray techniques. A number of techniques are being investigated by the Commonwealth Scientific and Industrial Research Organization for the on-line determination of moisture in coal. These include capacitance, microwave, neutron transmission and scattering, nuclear magnetic resonance and infra-red reflectance. One promising development is the non-contacting under-belt capacitance gauge for on-line conveyor belt determination of coal moisture. Laboratory experiments have shown that neutron techniques can be used to determine accurately the carbon and specific energy content of coal. Nuclear techniques have been used to determine coal mass flow to an industrial reverberatory furnace. (author)

57

Fluidized bed combustion of high ash Singareni coal  

Energy Technology Data Exchange (ETDEWEB)

Fluid bed combustion is comparatively a new technology for efficient combustion of high ash coals, which constitute the bulk of Indian coal resources. A 2-tonne equivalent steam per hour fluid bed combustion boiler was installed at the CPRI for experimentation with Indian coals and this paper discusses the salient features of tests conducted in the unit with minus 6 mm high ash Singareni coal of Andhra Pradesh. Data on combustion, heat transfer and heat utilization characteristics of the boiler under varying operating conditions show that high ash Singareni coal slacks can be burnt efficiently with high thermal efficiency, combustion efficiency and heat transfer rates from bed to surface in direct contact in a fluid bed combustion boiler. 3 refs., 5 figs., 4 tabs.

Mukherjee, M.K.; Biswas, R.R.; Mukherjee, S.K.; Talapatra, P.C.; Roy, R.U.; Rao, S.K.; Sen, M.M.

1986-04-01

58

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

59

A mathematical model of ash formation during pulverized coal combustion  

Energy Technology Data Exchange (ETDEWEB)

A mathematical model of ash formation during high-rank pulverized coal combustion is reported in this paper. The model is based on the computer-controlled scanning electron microscope (CCSEM) characterization of minerals in pulverized coals. From the viewpoint of the association with coal carbon matrix, individual mineral grains present in coal particles can be classified as included or excluded minerals. Included minerals refer to those discrete mineral grains that are intimately surrounded by the carbon matrix. Excluded minerals are those liberated minerals not or at least associated with coal carbon matter. Included minerals and excluded minerals are treated separately in the model. Included minerals are assumed to randomly disperse between individual coal particles based on coal and mineral particle size distributions. A mechanism of partial-coalescence of included minerals within single coal particles is related to char particulate structures formed during devolatilization. Fragmentation of excluded minerals, which is important particularly for a coal with a significant fraction of excluded minerals, is simulated using a stochastic approach of Poisson distribution. A narrow-sized sample of an Australian bituminous coal was combined in a drop-tube furnace under operating conditions similar to that in boilers. The particle size distribution and chemical composition of experimental ash were compared to those predicted with the model. The comparisons indicated that the model generally reflected the combined effect of coalescence of included minerals and fragmentation of excluded minerals, the two important mechanisms governing ash formation for high-rank coals. 22 refs., 8 figs., 1 tab.

Yan, L.; Gupta, R.P.; Wall, T.F. [University of Newcastle, Callaghan, NSW (Australia). Dept. of Chemical Engineering, Cooperation Research Center for Black Coal Utilization

2002-02-01

60

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

Directory of Open Access Journals (Sweden)

Full Text Available The adsorption of the cationic dye Crystal Violet (CV over zeolites from coal fly ash (ZFA and bottom ash (ZBA was evaluated. The coal fly ash (CFA and the coal bottom ash (CBA used in the synthesis of the zeolites by alkaline hydrothermal treatment were collected in Jorge Lacerda coal-fired power plant located at Capivari de Baixo County, in Santa Catarina State, Brazil. The zeolitic materials were characterized predominantly as hydroxy-sodalite and X. The dye adsorption equilibrium was reached after 10 min for ZFA and ZBA. 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 for both the adsorbents. The equilibrium data of ZFA was found to best fit to the Langmuir model, while ZBA was best explained by the Freundlich model. The maximum adsorption capacities were 19.6 mg g-1 for the CV/ZFA and 17.6 mg g-1 for the CV/ZBA.

Tharcila Colachite Rodrigues Bertolini

2013-11-01

61

Coal Ash Corrosion Resistant Materials Testing  

Energy Technology Data Exchange (ETDEWEB)

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

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

2007-12-31

62

Utilization of Coal Fly Ash as CO Gas Adsorbent  

Directory of Open Access Journals (Sweden)

Full Text Available This research focused on coal fly ash fabricated as CO adsorbent. Coal fly ash having grain size of 325 mesh was characterized by XRF, XRD and SEM-EDX. Physical activation was done at temperatures of 5000C, 5200C, 5400C, 5600C, 5800C and 6000C. Chemical activation was undertaken by mixing between fly ash and NaOH with mass ratio of 1: 1.2 with subsequent heating at 7500C for 1 h and followed by washing the specimens until pH=7. The samples were dried at 1000C for 1 h. The major constituents of unactivated coal fly ash are Fe, Ca, K, Si and Al in the form of quatz and anorthite. The chemical activation led to reduce the amount of quartz or increase the amount of anorthite. Physical activation does not affect the amount of minerals. Surface area of coal fly ash with physical activation at temperature 5400C and chemical activation is 32.444 m²/g (BET.doi: http://dx.doi.org/10.12777/ijwr.2.2.2012.13-15 [ How to cite this article: Sawitri, D., & Lasryza, A. (2012. Utilization of Coal Fly Ash as CO Gas Adsorbent. International Journal of Waste Resources (IJWR, 2(2, 13-15. doi: http://dx.doi.org/10.12777/ijwr.2.2.2012.13-15

Ayu Lasryza

2012-10-01

63

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

Science.gov (United States)

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. Integr Environ Assess Manag 2015;11:5-9. © 2014 SETAC. PMID:25348557

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

2015-01-01

64

Molybdenum transport in coal fly ash soil constructions  

Energy Technology Data Exchange (ETDEWEB)

There are remarkable possibilities to economically use a major part of coal fly ashes in soil construction applications. This, however, requires that the environmental effects of fly ashes are known and can be controlled. This paper discusses a research on the transport of molybdenum from ash structures to the environment in the long term. The research has involved both laboratory investigations on fly ash samples and tests on samples from full-scale constructions. The results have shown for example that; the amount of leachable molybdenum relative to the total content of molybdenum varies remarkably between the coal ashes from different sources; clay absorbs molybdenum more effectively than sandy moraine; with declining pH values the subsoil layer beneath the ash layer prevents further transport of molybdenum; the studies conducted at the 20 years old construction support the results of laboratory investigations. On the basis of the investigations a transport model was constructed for clay and moraine soils. The model can be used to calculate the transport of molybdenum in the soil and ground water beneath the coal ash layer during the next 100 years. The calculations indicate that the transport of molybdenum is insignificant and not beyond half meter under the fly ash structure. (orig.)

Lahtinen, P. [Viatek Ltd/SG, Luopioinen (Finland); Palko, J. [Envitop Oy, Oulu (Finland); Karvonen, T. [Helsinki University of Technology, Otaniemi (Finland)

2000-07-01

65

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2001-03-01

66

Utilisation of coal ash to improve acid soil  

Directory of Open Access Journals (Sweden)

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.

Shigeru Kato

2004-09-01

67

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)

68

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

69

Damage cost of the Dan River coal ash spill.  

Science.gov (United States)

The recent coal ash spill on the Dan River in North Carolina, USA has caused several negative effects on the environment and the public. In this analysis, I report a monetized value for these effects after the first 6 months following the spill. The combined cost of ecological damage, recreational impacts, effects on human health and consumptive use, and esthetic value losses totals $295,485,000. Because the environmental impact and associated economic costs of riverine coal ash spills can be long-term, on the order of years or even decades, this 6-month assessment should be viewed as a short-term preview. The total cumulative damage cost from the Dan River coal ash spill could go much higher. PMID:25497306

Dennis Lemly, A

2015-02-01

70

Community Views About the Health and Exposure of Children Living Near a Coal Ash Storage Site.  

Science.gov (United States)

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

Zierold, Kristina M; Sears, Clara G

2014-09-10

71

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

72

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

73

Toxicity of and metals in coal combustion ash leachate  

International Nuclear Information System (INIS)

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

74

On-conveyor belt determination of ash in coal  

Energy Technology Data Exchange (ETDEWEB)

A laboratory feasibility study has been carried out on new and advanced neutron and gamma-ray analysis systems for the direct on-conveyor belt analysis of ash in coal without the need for sample by-lines. Such an analysis system could deliver the combined advantages of a direct on-conveyor configuration with new and accurate analysis techniques. An industry survey of 18 coal companies carried out in early 1996 indicated that accurate on-belt ash analysis is of the highest priority. Subsequent laboratory work has focussed on the investigation of methods with the potential for improving the accuracy of ash content measurement relative to existing on-belt ash analysers, the most widely-used of which are based on dual energy gamma-ray transmission (DUET), which is sensitive to variations in ash composition. The current work indicates that on-belt neutron/gamma-ray techniques combined with advanced spectral analysis techniques show promise for development into an on-belt ash analysis system which is significantly less sensitive to composition changes than DUET and which analyses a much larger proportion of coal on the belt, thus eliminating some key sources of analysis error 9 refs., 2 tabs., 2 figs.

Sowerby, B.; Lim, C.S.; Abernethy, D.A.; Liu, Y.; Maguire, P.A. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Menai, NSW (Australia). Division of Minerals

1997-10-01

75

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.)

76

Monte Carlo simulation of a coal ash gauge  

International Nuclear Information System (INIS)

A computer model of a Coalscan pair production coal ash gauge has been developed. It is based on the MCNP Monte Carlo neutron and photon transport computer program. It has been used to systematically assess the effect that variations in a number of coal and gauge parameters have on instrument behaviour. These investigations have yielded quantitative indications of the sensitivity of gauge performance to variations in bulk density and moisture content of coal and to displacements of the sample presentation tube. They have confirmed that the current calibration procedure yields accurate results but that wear of the sample tube liner is a potential source of systematic error. A 5-parameter ash correlation has been proposed to improve accuracy when large variations in either the bulk density or the free moisture content or both of coal occur. Methods of compensation for the effect of tube liner wear have been suggested. (author)

77

Alkaline leaching of coal by the mechanochemical treatment  

OpenAIRE

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

Turèániová ¼udmila; Balá? Peter

1998-01-01

78

Alkaline leaching of coal by the mechanochemical treatment  

Directory of Open Access Journals (Sweden)

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

Turèániová ¼udmila

1998-09-01

79

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

Directory of Open Access Journals (Sweden)

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.

Abdulhameed Umar Abubakar

2012-11-01

80

Mineralogy and chemistry of conventional and fluidised bed coal ashes  

OpenAIRE

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

Sulovský P

2002-01-01

81

Preparation and characterization of carbon-enriched coal fly ash  

OpenAIRE

Carbon-enriched fractions have been obtained from two coal fly ash (FA) samples. The FA came from two pulverized-coal fired power stations (Lada and Escucha, Spain) and were collected from baghouse filters. Sieving was used to obtain carbon-enriched fractions, which were further subjected to two beneficiation processes: acid demineralization using HCl and HF, and oil agglomeration using soya oil–water. Yield in weight after sieving, unburned carbon content, and several physicochemical chara...

Rubio Villa, Begon?a; Izquierdo Pantoja, Mari?a Teresa; Mayoral Gasto?n, Mari?a Del Carmen; Bona, M. T.; Marti?nez Tarazona, M. ª. Rosa

2008-01-01

82

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

OpenAIRE

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(Si2Al)O6H2&...

Gon?i, S.; Pen?a, R.; Guerrero, A.

2010-01-01

83

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.)

84

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)

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.

Budi Sulistianto

2012-07-01

85

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

OpenAIRE

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...

Izquierdo, Maria; Querol, Xavier

2012-01-01

86

Radioactivity of coals, ashes and slags in the USSR  

International Nuclear Information System (INIS)

Concentrations of natural radionuclides in coals, ashes, and slags in samples from thermal power stations in USSR are given. The impact of this radioactivity on the environment is discussed and it is concluded that this radioactivity does not present any significant radiological hazard to the population

87

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

International Nuclear Information System (INIS)

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

88

Production of ceramics from coal fly ash  

OpenAIRE

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...

Angjusheva Biljana; Fidancevska Emilija; Jovanov Vojo

2012-01-01

89

High fire resistance in blocks containing coal combustion fly ashes and bottom ash.  

Science.gov (United States)

Fire resistance recycled blocks, containing fly ash and bottom ash from coal combustion power plants with a high fire resistance, are studied in this paper by testing different compositions using Portland cement type II, sand, coarse aggregate and fly ash (up to 50% of total weight) and bottom ash (up to 30% of total weight). The fire resistance, physical-chemical (density, pH, humidity, and water absorption capacity), mechanical (compressive and flexural strength), and leaching properties are measured on blocks made with different proportions of fly ash and bottom ash. The standard fire resistance test is reproduced on 28cm-high, 18cm-wide and 3cm-thick units, and is measured as the time needed to reach a temperature of 180°C on the non-exposed surface of the blocks for the different compositions. The results show that the replacement of fine aggregate with fly ash and of coarse aggregate with bottom ash have a remarkable influence on fire resistance and cause no detriment to the mechanical properties of the product. Additionally, according to the leaching tests, no environmental problems have been detected in the product. These results lead to an analysis of the recycling possibilities of these by-products in useful construction applications for the passive protection against fire. PMID:21511456

García Arenas, Celia; Marrero, Madelyn; Leiva, Carlos; Solís-Guzmán, Jaime; Vilches Arenas, Luis F

2011-08-01

90

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.

91

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

92

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

Science.gov (United States)

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

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

2010-12-15

93

The use of coal fly ash for soil stabilization  

Energy Technology Data Exchange (ETDEWEB)

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

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

1991-12-01

94

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

95

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

96

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

97

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

Energy Technology Data Exchange (ETDEWEB)

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

Wood, K.G.

1978-08-01

98

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

OpenAIRE

Coal ash is a byproduct of mineral coal combustion in thermal power plants. This residue is responsible for many environmental problems because it pollutes soil, water, and air. Thus, it is important to find ways to reuse it. In this study, coal fly ash, obtained from the Presidente Médici Thermal Power Plant, was utilized in the preparation of ceramic supports for the immobilization of the enzyme invertase and subsequent hydrolysis of sucrose. Coal fly ash supports were prepared at several ...

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

2014-01-01

99

Production of ceramics from coal fly ash  

Directory of Open Access Journals (Sweden)

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.

Angjusheva Biljana

2012-01-01

100

Mineralogy of Indian coal fly ash  

International Nuclear Information System (INIS)

Samples of ash obtained from a number of Indian thermal plants, from various points of collection have been chemically analysed and their stoichiometric mineral compositions have been calculated. Mineralogical constituents have also been determined by X-ray analysis as well as observed under optical microscope. The results have been compared. Formation of various mineral phases have been discussed and their environmental implication in solid waste disposal has been pointed out. (author). 22 refs

101

Radiometric determination of uranium leached biochemically from coal fly ashes  

International Nuclear Information System (INIS)

The method of radiometric determination of uranium leached by Thiobacillus ferrooxidans bacteria from fly ashes of hard and brown coals has been developed. The leached uranium was extracted from leaching medium by using toluene solution of tributylphosphate. To the organic phase containing extracted uranium the scintillation solution Permafluor 1 was added and solution activity was recorded using scintillation counter. The elaborated method enables to determine trace amounts of the leached uranium (?10-7 g/ml) in leaching solution containing bacterial culture Thiobacillus ferrooxidans and suspended ashes. (author)

102

Usage of Ash from Coal incineration in Wuhai, China  

OpenAIRE

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...

Sun, Shiyu

2007-01-01

103

The use of coal fly ash in sodic soil reclamation  

Energy Technology Data Exchange (ETDEWEB)

An experiment was conducted for two years in northwest India to explore the feasibility of using coal fly ash for reclamation of waterlogged sodic soils and its resultant effects on plant growth in padi-wheat rotation. The fly ash obtained from electrostatic precipitators of thermal power plant had a pH of 5.89 and electrical conductivity of 0.88 dS m{sup -1}. The treatments comprised of fly ash levels of 0.0, 1.5, 3.0, 4.5, 6.0 and 7.5 per cent, used alone as well as in combination with 100, 80, 60, 40, 20 and 10 per cent gypsum requirement of the soil, respectively. There was a slight reduction in soil pH while electrical conductivity of the soil decreased significantly with fly ash as measured after padi and wheat crops. The sodium adsorption ratio of the soil decreased with increasing fly ash levels, while gypsum treatments considerably added to its favourable effects. Fly ash application increased the available elemental status of N, K, Ca, Mg, S, Fe, Mn, B, Mo, Al, Pb, Ni, Co, but decreased Na, P and Zn in the soil. An application of fly ash to the soil also increased the concentrations of above elements except Na, P and Zn in the seeds and straw of padi and wheat crops. The available as well as elemental concentrations in the plants was maximum in the 0 per cent fly ash + 100 per cent gypsum requirement treatment except Na and heavy elements like Ni, Co, Cr. The treatment effects were greater in the fly ash gypsum requirement combinations as compared to fly ash alone. Saturated hydraulic conductivity and soil water retention generally improved with the addition of fly ash while bulk density decreased. Application of fly ash up to 4.5 per cent level increased the straw and grain yield of padi and wheat crops significantly in both years. The results indicated that for reclaiming sodic soils of the southwest Punjab, gypsum could possibly be substituted up to 40 per cent of the gypsum requirement with 3.0 per cent acidic fly ash.

Kumar, D.; Singh, B. [Punjab Agricultural University, Ludhiana (India). Dept. of Soil & Water Engineering

2003-06-01

104

Radioactivity of coals and ash and slag wastes at coal-fired thermal power plants  

Science.gov (United States)

This paper presents an analysis of published data on the content of radioactive nuclides in coals originating from various coal deposits, and in ash and slag wastes produced at coal-fired thermal power plants, as well as in fly ash emitted from thermal power plants into the atmosphere. Problems related to the use of coals with an elevated content of natural radionuclides (NRNs) and methods of their solution implemented at the Urtuyskoe coalfield are dealt with. Data on the analysis of Transbaikal coals for the NRN content, as well as weighted mean content of uranium and thorium in coals from the Siberian Region, are given. In order to reduce irradiation of plant personnel and the population of the areas where coal producers and coal-fired thermal power plants are located, it is necessary to organize very careful control of the NRN content in both coals and products of their combustion that are released into the environment. To solve the problem related to the control of radioactivity, the centralized approach and creation of a proper normative base are needed. Experience gained in developing the Urtuyskoe coalfield shows that it is possible to create an efficient system of coal quality control with respect to the radiation hygiene factor and provide protection of the environment and health of the population.

Krylov, D. A.; Sidorova, G. P.

2013-04-01

105

Effect of coal ash disposal upon an unconfined alluvial system  

International Nuclear Information System (INIS)

Fly and bottom ash from coal combustion has been disposed in four ash ponds in an alluvial valley. Three of the ash ponds are receiving ash and one was filled and closed. Twenty eight monitoring wells ranging in depth from 10 feet to 65 feet have been installed at the site to study groundwater flow and chemistry. Hydraulic heads are influenced by the stage of the Kentucky River, and the flow direction is vertical below the ash ponds and predominantly horizontal a short distance from the pond all the way to the river. Three different groundwater flow zones were observed and have unique water chemistry. The deep zone (near bedrock) has a low Eh ( 100) and lower concentrations of Fe and ammonia nitrogen, median sulfate concentration (114 mg/l), and arsenic is below detection limits. The shallow groundwater zone is through the closed out ash point and has higher concentrations of nearly all cations and anions, including sulfate (888 mg/l) and arsenic (exists as arsenite) at concentration of 0.9 mg/l, low Eh (< -100), and high pH. When shallow flow enters the alluvium, the sulfate are attenuated by sulfate reduction and this results in high bicarbonate values. Saturation indicesigh bicarbonate values. Saturation indices (SI) as calculated by the geochemical model, MINTEQA2, indicate that deep and intermediate groundwater are unsaturated and shallow groundwater is at or near equilibrium with respect to calcite, dolomite, and gypsum

106

Ash level meter for a fixed-bed coal gasifier  

Science.gov (United States)

An ash level meter for a fixed-bed coal gasifier is provided which utilizes the known ash level temperature profile to monitor the ash bed level. A bed stirrer which travels up and down through the extent of the bed ash level is modified by installing thermocouples to measure the bed temperature as the stirrer travels through the stirring cycle. The temperature measurement signals are transmitted to an electronic signal process system by an FM/FM telemetry system. The processing system uses the temperature signals together with an analog stirrer position signal, taken from a position transducer disposed to measure the stirrer position to compute the vertical location of the ash zone upper boundary. The circuit determines the fraction of each total stirrer cycle time the stirrer-derived bed temperature is below a selected set point, multiplies this fraction by the average stirrer signal level, multiplies this result by an appropriate constant and adds another constant such that a 1 to 5 volt signal from the processor corresponds to a 0 to 30 inch span of the ash upper boundary level. Three individual counters in the processor store clock counts that are representative of: (1) the time the stirrer temperature is below the set point (500.degree. F.), (2) the time duration of the corresponding stirrer travel cycle, and (3) the corresponding average stirrer vertical position. The inputs to all three counters are disconnected during any period that the stirrer is stopped, eliminating corruption of the measurement by stirrer stoppage.

Fasching, George E. (Morgantown, WV)

1984-01-01

107

Investigation on thermal radiation spectra of coal ash deposits  

Energy Technology Data Exchange (ETDEWEB)

This paper deals with thermal radiation properties of ash deposits on a pulverized coal boiler of an electric power plant. Normal emittance spectra in the 2.5-25 {mu} m interval, and total normal emittance, were measured on 4 kinds of ash layers of a mm magnitude order thickness, at 560 {yields} 1460 {yields} 560 K in heating and cooling. It was found that ash powder layers are opaque for infrared radiation. The emittance increases with ash radiation wavelength and temperature. Ash powder is sintered and fused above 1200 K. The emittance of the sintered layer is above that of the unsintered layer. The authors propose, and explain by an example, correlating the experimentally obtained emittance spectra of ash deposits with a continuous curve, the formula of which defines the dependence of emittance on wavelength and temperature, i.e. epsilon = epsilon(lambda,T). Use of this formula, with parameter values determined by the proposed methodology, may greatly simplify the practical application of the experimentally determined emittances in the thermal design of existing and new steam boiler furnaces.

Saljnikov, A.; Komatina, M.; Manovic, V.; Gojak, M.; Goricanec, D. [University of Belgrade, Belgrade (Serbia). Faculty of Mechanical Engineering

2009-05-15

108

Adsorption of herbicides on coal fly ash from aqueous solutions.  

Science.gov (United States)

Development of low cost adsorbent for pesticide retention is an important area of research in environmental sciences. The present study reports the sorption potential of coal fly ash, a waste from power stations, for removal of metribuzin, metolachlor and atrazine from water. Batch sorption method was used to study the sorption of herbicides from water. The amount of herbicides sorbed increased with increase in the amount of fly ash in the suspension. The maximum capacity of the fly ash to adsorb metribuzin, metolachlor and atrazine was found to be 0.20, 0.28 and 0.38 mg/g by Freundlich equation and 0.56, 1.0 and 3.33 mg/g by Langmuir equation. Freundlich adsorption equation better explained the results of herbicides sorption in fly ash as regression coefficient (R(2)) values were higher from Freundlich equation than the Langmuir equation. Adsorption isotherms were L-type suggesting that the herbicide sorption efficiency of fly ash depend on the initial concentration of herbicide in the solution and maximum removal of herbicide was observed at concentrations less than 10 microg/ml. The results of this study have implications in using the fly ash for removal of these herbicides from industrial and agricultural waste water and can find use as a material in the preparation of biobeds to minimize environmental contamination from pesticide use. PMID:19269091

Singh, Neera

2009-08-30

109

Adsorption of Rhodococcus Strain GIN-1 (NCIMB 40340) on Titanium Dioxide and Coal Fly Ash Particles.  

Science.gov (United States)

Rhodococcus strain GIN-1 (NCIMB 40340) can be used to enrich and isolate a titanium-rich fraction from coal fly ash. The gram-positive bacterium was isolated by its ability to adhere strongly and rapidly to suspended particles of pure titanium dioxide or coal fly ash. Adsorption depends on the salt concentration and occurs in seawater. Lowering of the salt concentration or washing of particles with pure water did not, however, cause desorption of the bacteria from TiO(2) particles; this was achieved by strong alkaline treatment or combined treatment with sodium dodecyl sulfate and urea but not with dilute acids, alcohols, or cationic or nonionic detergents. The bacterium exhibits higher affinity towards oxides of Ti and Zn than to other oxides with similar distribution of particle size. Moreover, it adheres much faster to TiO(2) than to magnetite (Fe(3)O(4)) or Al(2)O(3). After about 1 min, more than 85% of the cells were adsorbed on TiO(2), compared with adsorption of only 10 and 8% to magnetite and Al(2)O(3), respectively. Adsorption of the bacteria on TiO(2) occurs over a pH range of 1.0 to 9.0 and at temperatures from 4 to over 80 degrees C. Scanning electron microscopy combined with X-ray analysis revealed preferential adherence of the bacterium to coal ash particles richer in Ti. Stronger adhesion to TiO(2) was also demonstrated in the translocation of bacteria, preadsorbed on magnetite, to TiO(2) particles. The temporary co-adhesion to magnetite and TiO(2) was exploited for the design of a prototype biomagnetic separation process in which bacterial cells serve as an adhesive mediator between magnetite and TiO(2) particles in a mixture of Al, Si, and Ti oxides that simulates their proportion in the ash. PMID:16349369

Shabtai, Y; Fleminger, G

1994-09-01

110

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

OpenAIRE

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 a...

Argiz, C.; Mene?ndez, E.; Sanjua?n, M. A.

2013-01-01

111

Mineralogy and chemistry of conventional and fluidised bed coal ashes  

Directory of Open Access Journals (Sweden)

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.

Sulovský P

2002-03-01

112

Spectroscopic research on infrared emittance of coal ash deposits  

Energy Technology Data Exchange (ETDEWEB)

This paper deals with thermal radiation characteristics of ash deposits on a pulverized coal combustion boiler of an electric power plant. Normal emittance spectra in the near to medium infrared (2.5-25 {mu}m) region and total normal emittances were measured on four kinds of ground ash deposits. Measurements were conducted in the 570-1460 K temperature range which is common for boiler furnaces, by both heating and cooling the ash samples, with the aim to study the effect of their thermal history. Dependence of emittance on wavelength, temperature and chemical composition was studied, too. Samples were tested for transparency (opacity) to verify the accuracy of results. It was determined that the thicknesses used for the ash powders are opaque for infrared radiation for thicknesses in the order of a millimeter. Tests have shown that spectral emittance increases with an increase of wavelength with a characteristic pattern common for all samples. Spectral normal emittance increases strongly with temperature at shorter wavelengths and remains high and unchanged at longer ones. Emittance spectra are not very sensitive to chemical composition of ashes especially beyond {lambda} {approx} 5 {mu}m. With an increase of temperature, total emittance of the powdered sample decreases to a minimum value around 1200 K. Further temperature rise induces an increase of total emittance due to sintering in the ash. On cooling, the emittance increases monotonically following the hysteresis. Quantitative directions for evaluating thermal radiation characteristics of ash deposits for the merits of the safety design of boiler furnaces were proposed. That comprises correlating the experimentally obtained emittance spectra with curves of simple analytical form, i.e., a continuous function of minimum emittance vs. wavelength. The proposed method can be extended to other specimens from the same furnace and used to determine correlations for thermal calculation of old and design of new furnaces - with similar geometry and combusting similar coal. The method is potentially applicable to completely different boiler furnaces combusting different coal, and the authors recommend running the tests with new deposit samples. The data will then be applicable to the thermal design of a whole new class of furnaces, having similar geometry and combusting similar coal. This is expected to greatly enhance the accuracy and precision of thermal calculation as well as the efficiency of thermal design of steam boilers. (author)

Saljnikov, Aleksandar; Komatina, Mirko; Gojak, Milan [Department of Thermomechanics, Faculty of Mechanical Engineering, University of Belgrade, Kraljice Marije 16, 11120 Belgrade 35 (RS); Vucicevic, Biljana [Laboratory for Thermal Engineering, Institute of Nuclear Sciences VINCA, P.O. Box 522, Belgrade 11001 (RS); Goricanec, Darko [Faculty of Chemistry and Chemical Engineering, University of Maribor, Smetanova 17, Maribor 2000 (Slovenia); Stevanovic, Zoran [Faculty of Mining and Geology, University of Belgrade, Dusina 7, 11120 Belgrade 35 (RS)

2009-11-15

113

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

114

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

115

JV Task 6 - Coal Ash Resources Research Consortium Research  

Energy Technology Data Exchange (ETDEWEB)

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.

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

2008-04-01

116

Performance Evaluation of Highway Embankment Constructed Using Coal Ash  

OpenAIRE

The objective of this project was to assess the environmental and geotechnical performance of two highway embankments constructed using coal combustion fly ash. The environmental work focused on characterizing monitoring well water samples from the site before, during, and after construction. In addition, a number in in-situ lysimeter water samples were also tested during and after construction. In each case, water samplers were evaluated in terms of their constitutive organic and metal co...

Alleman, James E.; Fox, Patrick J.; Debattista, Daniel J.

1996-01-01

117

Direct Quantitative Analysis of Arsenic in Coal Fly Ash  

OpenAIRE

A rapid, simple method based on graphite furnace atomic absorption spectrometry is described for the direct determination of arsenic in coal fly ash. Solid samples were directly introduced into the atomizer without preliminary treatment. The direct analysis method was not always free of spectral matrix interference, but the stabilization of arsenic by adding palladium nitrate (chemical modifier) and the optimization of the parameters in the furnace program (temperature, rate of temperature in...

Sri Hartuti; Shinji Kambara; Akihiro Takeyama; Kazuhiro Kumabe; Hiroshi Moritomi

2012-01-01

118

Mosses accumulate heavy metals from the substrata of coal ash  

OpenAIRE

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...

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

2005-01-01

119

Thermal expansion of slag and fly ash from coal gasification  

OpenAIRE

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 ...

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

2006-01-01

120

[Informative document fly ash of coal-fired power plants.  

OpenAIRE

This "Informative document fly ash of coal-fired power plants" forms part of a series of "Informative documents waste materials". These documents are conducted by RIVM on the instructions of the Directorate General for the Environment, Waste Materials Directorate, in behalf of the program of action on "prevention and recycling of waste materials". In the documents a survey is given of the main facts and figures on specific waste materials...

Ih, Anthonissen; Kamphuis C

2012-01-01

121

Microcomputer technique in on-line measurement of coal ash content  

International Nuclear Information System (INIS)

The on-line measurement of coal ash content is a key technique urgently needed in coal industry. In principle it can be realized using nuclear technology. But it's practice only when microcomputer is introduced. The paper describes the microcomputer technique used in the on-line coal ash content measurement by bi-energy ?-ray transmission method

122

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

123

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)

124

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)

125

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

Directory of Open Access Journals (Sweden)

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.

Kae-Long Lin

2013-07-01

126

Evaluation and Treatment of Coal Fly Ash for Adsorption Application  

Directory of Open Access Journals (Sweden)

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.

Samson Oluwaseyi BADA

127

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

128

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

OpenAIRE

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 f...

Du Plessis, Pieter W.; Ojumu, Tunde V.; Fatoba, Ojo O.; Akinyeye, Richard O.; Petrik, Leslie F.

2014-01-01

129

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.)

130

A study of the viscosity of coal ash and slag  

Science.gov (United States)

In this investigation, over 18,000 data points of amorphous material from coal ash deposition as identified by the scanning electron microscopy point count routine (SEMPC) were analyzed using cluster analysis methods. The cluster analysis performed in this investigation was done to ascertain if the bulk of coal ash deposit material could be represented by a small number of compositions. Three separate cluster routines were used. The top five clusters represented greater than 66% of the total sample population. The composition of the top five clusters are a calcium sulfur phase, a calcium-alumino-silicate with Si/Al ratio of one, a calcium-alumino-silicate with a Si/Al ratio of two, an iron-alumino-silicate with a Si/Al ratio of two, and an alumino-silicate phase with a Si/Al ratio of two. In all five of these compositions, Na, Mg, and K vary from one to five percent with all other elements having a weight percent less than two percent. The development of a neural network to model temperature-composition-viscosity relationships was implemented using two neural networks, a backpropagation of errors (BP) and a group method of data handling (GMDH) network. Both networks were trained using a data set of temperature-composition-viscosity points taken from the glass, metallurgical, geology, and coal ash literature. This data set consisted of greater than 2700 data points. Nine coal ash slags were selected for viscosity testing in this study. The slags were chosen in part to be similar in composition to the cluster compositions found in the cluster analysis portion of this investigation. Neural network models were compared to the performance of more recent models from the literature. The performance of the two neural networks when applied to the slags used in this study waS very similar. The GMDH had an average error over the nine slags used in this study of 25% and the BP, an average error of 29%. Both of the neural network models performed much better than two models that are fairly widely used in coal ash viscosity measurement.

Folkedahl, Bruce Carlton

131

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

OpenAIRE

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...

Kae-Long Lin; Ju-Ying Lan

2013-01-01

132

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

133

Environmental evaluation of coal ash from Chandrapura Thermal Power Station of Damodar Valley Corporation  

International Nuclear Information System (INIS)

This study envisages the environmental assessment of coal ash disposal from Chandrapur thermal power station. Environmental evaluation of coal ash is made through the analysis of leachates from open percolation leaching column experiments and also from the actual ash pond disposal site over a period of 10 months. Results of this study indicated that leachate analysis from open percolation column experiments closely resembles leachate analysis of actual ash pond disposal site. The pH, conductivity, total dissolved solids and trace elements were observed with the regulatory limits. Overall this study reveals that coal ash from this power plant is environmentally benign. (author)

134

Geotechnical Properties of Some Coal Fly Ash Stabilized Southwestern Nigeria Lateritic Soils  

Directory of Open Access Journals (Sweden)

Full Text Available This study on stabilization of tropical lateritic soils using self-cementing coal fly ash evaluated the effects of the addition of self-cementing coal fly ash on the engineering properties of three lateritic soils from southwestern Nigeria. The engineering properties investigated were those normally involved in highway design and construction. Increasing percentages (by weight of dry soil of coal fly ash, ranging from 0% through 15% in 2.5% increments, were added and the geotechnical properties assessed. It was observed, for all the soils, that increasing coal fly ash contents brought about increasing improvements in the plasticity and mechanical properties of the soils. When comparing the average value of the properties at 0% coal ash content to their average values at 12.5% coal ash content, there was a reduction in the liquid limits (from 39% to 33%, a reduction in the plasticity indices (from 15.3% to 9.3%, a reduction in the optimum moisture contents (from 15.8% to 9.7% accompanied by an increase in the maximum dry densities (from 1920 to 2200 kg/m3, and an increase in the unsoaked CBR values (from 20% to 55.3%. For the stabilization of lateritic soils with coal fly ash, a coal fly ash of 12.5% by weight of dry soil was recommended because the improvements in the soil’s properties tapered off at about that percentage of coal ash content.

Emmanuel Akintunde Okunade

2010-11-01

135

Economic evaluation of the ash of run-of-mine coking coals from the Karaganda coalfield. [Price penalty for high ash coal  

Energy Technology Data Exchange (ETDEWEB)

Economically justified reductions in price must be established for coals which exceed the average levels of ash. The reduction must compensate for the extra cleaning costs involved; this is a general principle in the approach to the economic evaluation of product quality. The reduction in price should be determined by the relative loss incurred by the consumer in accepting higher-ash coal. The basis for the economic evaluation of ash fluctuations should be the effects on washery output and cleaning costs of accepting coals with differing initial ash contents. Our investigations into the relationships between the quality, quantity, and cost indices of the cleaning process for Karaganada coals of different ash levels have shown that the most reliable procedures for economic evaluation are given for the various coal preparation plants. In calculating the over-all costs, the variations in run-of-mine coal consumption for the production of unit weight of final product should be measured by the variances in the yield of concentrate at a constant ash, rather than all washery products. The adoption of these procedures has shown that for each extra 1% of ash in the run-of-mine coals, brought about by an increase in the proportion of dirt they carry, the price reduction should be 2.5%, rather than 4.82% as proposed in the article under discussion.

Yurkina, L.P.; Sheveleva, R.N.; Kurbatov, V.P.; Korkina, T.B.

1981-01-01

136

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2009-07-01

137

Characteristics and composition of fly ash from Canadian coal-fired power plants  

Energy Technology Data Exchange (ETDEWEB)

Fly ashes were collected from the electrostatic precipitator (ESPs) and/or the baghouse of seven coal-fired power plants. The fly ashes were sampled from power plants that use pulverized subbituminous and bituminous feed coals. Fly ash from bituminous coals and limestone feed coals from fluidized-bed power plant were also sampled. The fly ashes were examined for their mineralogies and elemental compositions. The fly ashes from pulverized low sulfur coals are ferrocalsialic, those from high sulfur coals are ferrosialic and the fly ashes from the fluidized bed coals are ferrocalcic. The concentrations of As, Cd, Hg, Mo, Ni, and Pb in fly ash are related to the S content of the coal. The S content of fly ash from high S coal is 0.1% for pulverized ESP fly ash and 7% for baghouse fly ash from the fluidized bed, indicating that most of the S is captured by fly ash in the fluidized bed. The baghouse fly ash from the fluidized bed has the highest content of Cd, Hg, Mo, Pb, and Se, indicating that CaO, for the most part, captures them. Arsenic is captured by calcium-bearing minerals and hematite, and forms a stable complex of calcium or a transition metal of iron hydroxy arsenate hydrate in the fly ash. Most elements in fly ash have enrichment indices of greater than 0.7 indicating that they are more enriched in the fly ash than in the feed coal, except for Hg in all ESP ashes. Mercury is an exception; it is more enriched in baghouse fly ash compared to ESP. Fly ash collected from a station equipped with hot side ESP has a lower concentration of Hg compared to stations equipped with cold side ESP using feed coals of similar rank and mercury content. Fly ash particles from fluidized bed coal are angular and subangular with cores of quartz and calcite. The quartz core is encased in layer(s) of calcium-rich aluminosilicates, and/or calcium/iron oxides. The calcite core is usually encased in an anhydrite shell. 52 refs., 5 figs., 5 tabs.

Fariborz Goodarzi [Natural Resources Canada, Calgary, AB (Canada). Environmental Study Group, Earth Science Sector-Calgary Division

2006-08-15

138

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

OpenAIRE

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...

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

2014-01-01

139

Chromium and nickel speciation in Canadian feed coals, bottom ashes and fly ashes  

Energy Technology Data Exchange (ETDEWEB)

Chromium and nickel are listed as hazardous air pollutants in the 1990 U.S. Clean Air Act Amendments because of the well-known toxic and carcinogenic properties of the hexavalent oxidation state for chromium, and the carbonyl and subsulphide compounds of nickel. Consequently, it is important to determine the speciation of both Cr and Ni in order to assess their health and environmental impacts, especially in coal combustion. In this work, the speciation of Cr and Ni in Canadian feed coals and their combustion by-products were determined using a combination of XAFS spectroscopy and leaching studies. The concentrations of Cr and Ni in the Canadian feed coals varied from 5 to 10 mg/kg and 4 to 14 mg/kg respectively. Variation in the Cr and Ni oxidation states in ash products was observed, which may reflect their original speciation in the coal, the overall ash chemistry, the combustion conditions, or some combination of these three factors. 13 refs., 9 figs., 2 tabs.

F. Goodarzi; F.E. Huggins [Environmental Study Group, Calgary, AB (Canada). Geological Survey of Canada-Calgary Division

2003-07-01

140

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

141

Particle-induced X-ray emission (PIXE) analysis of coal fly ash  

International Nuclear Information System (INIS)

Analysis of trace element in coal fly ash has been brought to the attention of the general public in recent years primarily as it concerns in pollution problem with coal-fired power plants. Indian coal used in the thermal power plants has quite high content of ash (upto 55%). Therefore, in order to assess the environmental impact of the coal fuel cycle, coal fly ash samples from Captive Power Plant (CPP) of National Aluminium Company (NALCO) in Angul industrial area have been analysed for heavy elements by PIXE technique. Sample preparation procedures, experimental setup and spectrum analysis are discussed. (author)

142

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

Science.gov (United States)

In India, so far not much efforts have been made to use coal ash as backfill material in underground/ open cast mines and to predict its subsequent effect on ground water quality. One of the main problems in disposing of big quantities of coal ash is the possible leaching of different pollutants, including manganese. A thorough investigation regarding leaching of manganese from different fly ashes is required to know the impact of manganese due to its leaching from fly ash to ground water as well as surface water. In the present study, short term and long term leaching studies have been carried out on fly ash, bottom ash, pond ash and weathered ash of Chandrapura thermal power plant, Bokaro, Jharkhand and Ramagundam thermal power plant, Ramagundam, Andhra Pradesh. The amount of manganese released in different experiments has been evaluated. The leachate of Chandrapura fly ash has more manganese concentration (0.2001 mg/L) than the leachate of bottom ash, pond ash and weathered ash. A field investigation at Damoda abandoned open cast mine, filled with pond ash of Chandrapura thermal power plant revealed that concentration of manganese in ground water beneath the ash filled mine has been found very high (maximum up to 6.0 mg/L). But its migration to a long distance has not been seen. Remedial measures for coal ash disposal have also been formulated. PMID:21114150

Prasad, Bably; Mondal, Kajal K R

2009-01-01

143

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

OpenAIRE

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,...

Jankovi? M.M.; Todorovi? D.J.; Nikoli? J.D.

2011-01-01

144

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

Science.gov (United States)

A total of 18 elements viz. Si, Al, Fe, Ca, Mg, K, Na, Sr, V, Zn, Mn, Cr, Cu, Pb, Ni, Co, As and Cd were analyzed in coal, fly ash and bottom ash samples collected across India using an EDXRF technique. Various indices such as element enrichment ratio, enrichment factor (with respect to crustal average) and mineral composition were calculated. Around 95% of mass was reconstructed using the concentration of elements in this study for fly and bottom ash. PMID:24685495

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

2014-08-01

145

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

OpenAIRE

[EN] 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...

Argiz, C.; Sanjua?n, M. A.; Mene?ndez, E.

2013-01-01

146

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

Directory of Open Access Journals (Sweden)

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.

Nabih K.

2014-04-01

147

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

148

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

Science.gov (United States)

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

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

149

Oxygen in U. S. Bureau of Mines's coal ash, U. S. Bureau of Standards's coal fly ash reference mineral and low temperature coal ash. A simplified approach to the analysis of ash and material matter in coal  

Energy Technology Data Exchange (ETDEWEB)

Oxygen is determined accurately in eight U. S. Bureau of Mines Coal Ash samples A, B, D, F, G, I, and J, N.B.S. Coal Fly Ash 1633 Reference Material, and two Low Temperature Ashes from Illinois State Geological Survey. The method uses fast-neutron activation analysis employing a dual counting and irradiation system which is essentially free of interferences. The stoichiometric balance based on analyses of the ashes performed by the U.S.B.M. is calculated and summations given in oxide and element percent. Excellent agreement is found with the chemical data obtained by classical silicate analysis methods. Accurate oxygen determination for coal ash and LTA ash (or mineral matter) is important for calculation of data in the ultimate analysis of coal as such and is required for recalculation of the data on a ''dry'' and ''dry ash free'' basis. The routinely used ''oxygen by difference'' values are inadequate for accurate work. It is found that the eight coal ash samples analyzed contain 45.5 +- 3% oxygen. Since these ashes represent a large variety of U. S. coals, this figure can be used as an estimate for recalculation and evaluation of the Proximate and Ultimate Coal Analyses.

Volborth, A.

1976-08-20

150

Characterization of iron-bearing phases in coal and their ash  

International Nuclear Information System (INIS)

Moessbauer spectroscopy and X-ray diffraction techniques have been used to characterize the iron-bearing phases in coal and their ash formed at 500deg C. The analysis of the Moessbauer parameters and X-ray diffraction results show the presence of siderite, illite, pyrite and kaolinite in coal and hematite in ash as dominant minerals. (orig.)

151

Radon and thoron flux densities from some of NSW coal ash dams  

International Nuclear Information System (INIS)

The use of coal as an energy source can cause some potential environmental and human health hazards associated with radionuclides mobilized by the coal fuel cycle. The objective of this study was to assess environmental significance of radon and thoron emissions from New South Wales coal ash storage dams operated by Pacific Power. To achieve this objective radon and thoron flux densities were measured from selected ash dams and mine spoil areas. It was found that: (i) ash dams currently in operation exhibit significantly lower flux densities than average values for Australian soils, and (ii ash dams under rehabilitation and mine spoils have flux densities comparable to Australian soil. 18 refs., 2 tabs

152

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

International Nuclear Information System (INIS)

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

153

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

International Nuclear Information System (INIS)

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

154

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-07-15

155

Respiratory and reproductive characteristics of eastern mosquitofish (Gambusia holbrooki) inhabiting a coal ash settling basin.  

Science.gov (United States)

Coal fly ash and effluent from coal ash settling basins negatively affects metabolism and reproduction in a variety of organisms, including a number of fish species. Some species, most notably the eastern mosquitofish (Gambusia holbrooki), are known to maintain viable populations in areas contaminated by coal ash. While eastern mosquitofish are present in these systems, their degree of tolerance to coal ash has not been investigated using sublethal metrics of exposure. It is possible that eastern mosquitofish persist in habitats affected by coal ash, but experience significant costs such as changes in metabolism and fecundity. Thus, we investigated the effects of coal ash on standard metabolic rate and reproduction of eastern mosquitofish inhabiting a coal-ash contaminated settling basin. Standard metabolic rates of mosquitofish from the ash contaminated site and a reference site (mean O2 consumption = 0.286 mL/g x h +/- 0.007 and 0.291 +/- 0.008 mL/g x h, respectively) were not significantly different. Despite elevated contaminant concentrations in ash basin females (selenium, arsenic, copper, and cadmium) and their offspring (selenium), brood sizes and offspring viability did not differ between clutches collected from ash basin and reference site females. Our data provide further evidence of the high degree of tolerance of eastern mosquitofish to exposure to aquatic coal ash disposal generated by power plants. However, the basis for such tolerance to ash remains unclear. Further investigations are required to determine whether such tolerance is a result of species-specific characteristics or population characteristics due to local adaptation. PMID:15025168

Staub, B P; Hopkins, W A; Novak, J; Congdon, J D

2004-01-01

156

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

Science.gov (United States)

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

Chithiraputhiran, Sundara Raman

157

Uranium content in coal and fly ash samples  

International Nuclear Information System (INIS)

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

158

Mineralogy and microstructure of sintered lignite coal fly ash  

Energy Technology Data Exchange (ETDEWEB)

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.

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

2003-02-01

159

Investigation of the coal fly ashes using IR spectroscopy  

Science.gov (United States)

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

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

2014-11-01

160

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

161

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

Energy Technology Data Exchange (ETDEWEB)

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. Interference caused by the ions are within the tolerance limits. Beer's law is obeyed for concentration range to 0.6 mg/mL (aqueous solution) and to 1.2 mg/mL P (MIBK). The sensitivity of the proposed method is 0.0078 mg/mL (aqueous solution) and 0.0066 mg/mL (MIBK).

Randjel P. Mihajlovic; Natasa R. Ignjatovic; Marija R. Todorovic; Ivanka Hoclajtner-Antunovic; Vesna M. Kaljevic

2003-07-01

162

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

OpenAIRE

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 ...

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

2003-01-01

163

JV Task 120 - Coal Ash Resources Research Consortium Research  

Energy Technology Data Exchange (ETDEWEB)

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.

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

2009-03-28

164

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)

165

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

DEFF Research Database (Denmark)

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.

Arvelakis, Stelios; Folkedahl, B.

2006-01-01

166

The valuation of trends flotability of non-burnt coal residuals /combustibe components from fly ash.  

OpenAIRE

Possibilities of the utilisation of energetical wastes in civil engineering applications is limited due to the content of residuals of non-burnt coal, magnetite iron, refined fly ash. The flotation is able to reduce the content of residuals of non-burnt coal in the ashes from coals. The optimum quantity of collector, required time of duration of the process, the number of purifying and control flotations, the percentage of combustible substances in all flotation products are very important fl...

Benková Marta

2004-01-01

167

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

Directory of Open Access Journals (Sweden)

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.

Kisi? Dragica M.

2013-01-01

168

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

Science.gov (United States)

Coal fired thermal power contributes 70% of power in India. Coal fired power generation results in huge amounts of fly ash and bottom ash of varying properties. Coal, which contains the naturally occurring radionuclides, on burning results in enrichment of these radionuclides in the ashes. In the present study, coal, bottom ash and fly ash samples collected from six coal-fired power plants in India were measured for (210)Po using alpha spectrometry and for natural U, (226)Ra, (232)Th and (40)K by an HPGe ?-ray spectrometer. (210)Po in fly ash ranged from 25.7 to 70 Bq/kg with a mean value of 40.5 Bq/kg. The range and mean activities of (238)U, (226)Ra, (232)Th, (40)K in fly ash were 38.5-101 (78.1), 60-105.7 (79), 20-125 (61.7) and 43.6-200 (100) Bq/kg respectively. Fly ash and bottom ash contains two to five times more natural radionuclides than feed coal. The results were compared with the available data from earlier studies in other countries. The effect of particle size on enrichment factor of the nuclides in fly ash was studied. (210)Po showed the largest size dependence with its concentration favoring the smaller particle size while (232)Th showed least size dependence. (238)U and (226)Ra showed behavior intermediate to that of (210)Po and (232)Th. Also the correlation between sulfur content of the feed coal and activity of (210)Po was investigated. Increased sulfur content in feed coal enhanced enrichment of (210)Po in ash. PMID:24813148

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

2014-12-01

169

The partitioning behaviour of boron from tourmaline during ashing of coal  

Energy Technology Data Exchange (ETDEWEB)

Boron is an environmentally sensitive element that may be present in high concentrations in some coals. Three modes of occurrence for boron in coal are commonly recognised, namely, bound to the organic fraction, locked into clay minerals (mainly illite), and bound within the crystal lattice of tourmaline. The organically bound mode is generally considered to be the most likely. Following combustion in a pulverised fuel utility, boron is generally enriched in the fine fly ash waste, but in some cases, it may also escape with the flue gas, suggesting variable partitioning behaviour. There is concern that boron may be leached from fly ash disposal impounds at concentrations toxic to higher land plants. A coal sample from the D Seam of the Strongman No. 2 Mine, West Coast, South Island, New Zealand has been used to test the hypothesis that boron present in tourmaline is less volatile in coal combustion, implying that mode of occurrence is a key control on the partitioning behaviour of this element. Six sample subsets were doped with increasing amounts of ground tourmaline. One subsample from each set was analysed by prompt gamma INAA to determine the concentration of boron in the coal. Two subsamples were ashed at 1000 C. One ash sample from each set was analysed for boron, while the other ash sample was leached according to Australian standards. It was found that the relationship between boron in the doped coal and boron in the ash is approximately linear (with some losses noted during ashing), indicating boron present in tourmaline was substantially retained in the ash. Furthermore, no relationship was found between the boron content of the ash and boron leached from the ash samples by reagent water. The results suggest boron present in coal as tourmaline is retained in the ash and is unavailable to the environment following fly ash disposal.

Boyd, R.J. [James Cook University, Henderson, KY (Australia)

2002-12-01

170

Design and testing controlled low-strength materials (CLSM) using clean coal ash  

Energy Technology Data Exchange (ETDEWEB)

The major objective of this project was to develop mixture proportions for controlled low-strength material (CLSM) using clean coal ash obtained from atmospheric fluidized bed combustion (AFBC). A clean coal ash is defined as the ash derived from SO{sub x} and NO{sub x} control technologies. The specific ashes used for this project were: (1) circulating fluidized bed boiler fly ash and bottom ash and (2) stoker-type boiler fly ash and bottom ash. These two coal ash samples were characterized for physical and chemical properties. Chemical properties and water leaching tests were also performed on the hardened CLSM. Many initial CLSM mixtures were developed by blending the two types of ash. Tests conducted on the final three selected CLSM mixtures included compressive strength, bleeding, setting and hardening, settlement, length change of hardened CLSM, permeability, mineralogy, and chemical water leach testing. Results show that acceptable CLSM material can be developed by blending the fluidized bed boiler ash with the stoker boiler ash. Recommendations for a pilot scale manufacturing application of the three CLSM mixtures were made based upon the lab test results.

Naik, T.R.; Kraus, R.N. [Univ. of Wisconsin, Milwaukee, WI (United States); Sturzl, R.F. [Manitowoc Public Utilities, WI (United States); Ramme, B.W. [Wisconsin Electric Power Co., Milwaukee, WI (United States)

1998-10-01

171

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

Science.gov (United States)

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

Ikeda, Michitaka; Kozai, Yukitoshi; Makino, Hisao

172

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

International Nuclear Information System (INIS)

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

173

Determination of radioactive trace elements in ashes and fly-ashes from Brazilian coal-fired power plants  

International Nuclear Information System (INIS)

The aim of this work was to apply a epithermal neutron activation technique to determine the uranium and thorium content in coal ashes and fly ashes from Brazilian coal-fired thermoelectric plants and to evaluate the contribution of these elements and their descendents to the environmental radioactivity. Brazil has adopted as short term policy the use of alcohol and coal as alternative sources of energy. With regard to coal, large deposits of this mineral are found in southern states but the serious problem of its utilization is the risk of environmental contamination which can reach dangerous levels because the industrial plants burn several million tons per year. Uranium and thorium contents, determined experimentally, are extrapolated for annual coal consumption and their amounts and the activity of the radium isotopes descendents released to the atmosphere are calculated. The significance of these values and problems in environmental pollution are discussed

174

Practical recycling application of power plant coal ash for high performance shotcrete material  

Energy Technology Data Exchange (ETDEWEB)

This study aims to enhance practical application of coal ash as a shotcrete construction material. Derived were optimum mix proportions for high performance shotcrete using coal ash. In order to enhance long term performance, silica fume was also added. Experimental variables included replacement ratio of silica fume and coal ash. Compressive strength and potential hazardous contamination to soil were the primary factors in the performance evaluation. From the test results, when fly ash was replaced up to 10% of the cement, most required specifications were satisfied. Hazardous material content was shown to be well below the specifications. Therefore, when appropriate caution in handling is given in the field, it is strongly anticipated to increase the coal ash recycling as a shotcrete construction material.

Cheolwoo Park; Kyung Nam Kim [Kangwon National University Samcheok (Republic of Korea)

2009-07-01

175

Rheology of fly ashes from coal and biomass co-combustion  

DEFF Research Database (Denmark)

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

Arvelakis, Stelios; Frandsen, Flemming

2010-01-01

176

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

Science.gov (United States)

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

Popovic, A; Djordjevic, D; Polic, P

2001-04-01

177

Speciation of chromium in feed coals and ash byproducts from Canadian power plants burning subbituminous and bituminous coals  

Energy Technology Data Exchange (ETDEWEB)

The chromium species in the feed coals and ash byproducts from seven Canadian coal-fired power plants were examined using Cr X-ray absorption near-edge spectroscopy. Chromium in the Canadian feed coals is always found as Cr{sup 3+} but generally has a dual occurrence, as Cr{sup 3+} is distributed to varying degrees between the clay mineral illite and a poorly crystallized chromium oxyhydroxide phase associated with the organic fraction. In two subbituminous feed coals from Alberta, chromium is present largely as Cr{sup 3+}/illite, whereas in two other such coals, it is present predominantly as CrOOH. Chromium in a low-sulfur bituminous feed coal from Alberta is found mostly as Cr{sup 3+}/illite, whereas for feed coals from Nova Scotia with high sulfur contents, chromium is distributed between both Cr{sup 3+}/illite and CrOOH. Very little chromium was found in the limestone used in a fluidized-bed combustor. The chromium species in most bottom ash samples from all seven combustion units is predominantly, if not entirely, Cr{sup 3+} associated with aluminosilicate phases. Chromium speciation for subbituminous electrostatic precipitator fly ash is mostly Cr{sup 3+}, but in some cases, it is slightly lessand varies by sampling location at the plant. Chromium in fly ash from the combustion of bituminous feed coals is predominantlyCr{sup 3+}. A unique species of chromium found in one feed coal and an unrelated fly ash is metallic chromium, similar to that in stainless steel. The occurrence of this form of chromium in these materials indicates contamination from machinery, such as the coal milling machine or possibly wearing down of stainless steel parts by the coal or ash. The observation of this unexpected contamination demonstrates the power and usefulness of X-ray absorption fine-structure spectroscopy for speciation determination. 35 refs., 6 figs., 4 tabs.

Fariborz Goodarzi; Frank E. Huggins [Geological Survey of Canada-Calgary Division, Calgary, AB (Canada)

2005-12-01

178

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

179

Speciation of nickel in Canadian subbituminous and bituminous feed coals, and their ash by-products  

Energy Technology Data Exchange (ETDEWEB)

The nickel species in the feed coals and ash by-products from seven Canadian power plants (including one with a fluidized bed combuster) burning local subbituminous and bituminous coals with sulfur contents ranging from 0.22 to 3.6% have been examined using nickel XANES spectroscopy. XANES spectroscopy of Ni in coal and coal derived ash is complicated by a poor signal:noise ratio due to fluorescence of the much more abundant iron in the coal. Nevertheless, it has proved possible to show that the Ni environment in coals varies from largely oxidic species to mixtures of Ni-containing oxide and sulfide species. The nickel in one oxidized coal appears to be present as nickel sulfate. Nickel in all bottom and fly ash samples examined appears also to be present largely in oxygen anion environments. With the exception of one fly ash sample, for which the Ni exhibited spectral features similar to those for Ni{sup 2+} in spinel or oxide phases, the nickel in the bottom and fly ash samples appears to exist largely as Ni{sup 2+} in environments similar to those reported for Ni in silicate glasses. The data obtained indicate that the presence of potentially carcinogenic nickel sulfides in ash by-products from combustion of these coals is unlikely.

Goodarzi, F.; Huggins, F. [Geological Survey of Canada, Calgary, AB (Canada). Calgary Division

2004-07-01

180

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)

181

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)

182

Speciation of nickel in Canadian subbituminous and bituminous feed coals, and their ash by-products.  

Science.gov (United States)

The nickel species in the feed coals and ash by-products from seven Canadian power plants (including one with a fluidized bed combuster) burning local subbituminous and bituminous coals with sulfur contents ranging from 0.22 to 3.6% have been examined using nickel XANES spectroscopy. XANES spectroscopy of Ni in coal and coal derived ash is complicated by a poor signal : noise ratio due to fluorescence of the much more abundant iron in the coal. Nevertheless, it has proved possible to show that the Ni environment in coals varies from largely oxidic species to mixtures of Ni-containing oxide and sulfide species. The nickel in one oxidized coal appears to be present as nickel sulfate. Nickel in all bottom and fly ash samples examined appears also to be present largely in oxygen anion environments. With the exception of one fly ash sample, for which the Ni exhibited spectral features similar to those for Ni(2+) in spinel or oxide phases, the nickel in the bottom and fly ash samples appears to exist largely as Ni(2+) in environments similar to those reported for Ni in silicate glasses. The data obtained indicate that the presence of potentially carcinogenic nickel sulfides in ash by-products from combustion of these coals is unlikely. PMID:15480491

Goodarzi, Fariborz; Huggins, Frank

2004-10-01

183

Brown coal ash content gauge employing ZX Spectrum microcomputer  

International Nuclear Information System (INIS)

The gauge, apart of a measuring head, contains microcomputer ZX Spectrum, CRT tube monitor or a TV set and an interfacing circuit consisting of: 24 lines decoder for 1/0 devices, pulse amplitude to digit converter in the range 0-255, programmable counters seving as a real time clock and an interrupt circuit, as well as ERD-103 printer interface. The instrument measures the differential spectra of output pulses from proportional counter, corresponding to measured coal sample. Three measuring windows are then determined corresponding to: calcium excited radiation, iron excited radiation and backscattered radiation, and basing on it, the ash content is computed. The results of measurement are displayed on CRT tube monitor or on TV screen and printed by the printer. (author)

184

Dilithium dialuminium trisilicate Crystalline Phase Prepared from Coal Fly Ash  

Science.gov (United States)

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.

Yao, Zhitong; Xia, Meisheng; Ye, Ying

2012-06-01

185

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

OpenAIRE

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

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

2013-01-01

186

Use of coal ashes as a binder for solidifying municipal waste incineration residues  

Energy Technology Data Exchange (ETDEWEB)

From previous and ongoing ECSC research works, it was thought possible to associate different coal ashes for making binders with very good performance. For example the authors succeeded in making standard mortars reaching more than 50 mpa compression strength by using only sand, water and coal ashes. Moreover, the sand/ash mortar beams swelled less under water than the reference sand/CEM cement mortar beams. The heat of hydration measured on mortars by the Langavants method was four less with the sand/ash mortar than that with sand/cement.

Blondin, J. [CERCHAR, Mazingarbe (France)

1999-07-01

187

Mobility of heavy metals from coal fly ash  

Science.gov (United States)

The mobility of Cd, Co, Cu, Ni, Pb, Sb, and Zn from six different coal-fired power plant fly ashes that show a wide compositional range was examined using a sequential extraction procedure in order to assess their mobility when these wastes are ponded or landfilled. The extraction sequence was as follows: (1) water extractable, (2) cation exchangeable (CH3COONH4 at pH 7), (3) surface oxide-bound cations (CH3COONH4 at pH 5), (4) Fe oxide-bound cations (HONH3Cl), and (5) residual (HF, HCl, HNO3, 2?1?1). The heavy metal contents in the extraction solutions were determined by anodic (Cd, Cu, Pb, Sb, and Zn) and cathodic (Ni and Co) stripping voltammetry. The results reveal differences in the total contents of the selected trace elements among the fly ash samples, which must be related to differences in coal composition and combustion technology. The extractable fraction under natural conditions ranges from 1.5 to 36.4 percent of the total element content. Cadmium, Co, Cu, and Zn show the highest extractable fraction (10.8 18.9 percent on average). Cadmium is the most easily water-extractable element, while Co, Cu, and Zn increase their mobility as the severity of the extraction increases. Cobalt, Ni, Pb, and Zn are mainly associated with the surface oxide-bound and Fe oxide-bound fractions. Nickel, Pb, and Sb have low mobility potentials (5.3 6.6 percent as extractable fraction), but Sb presents a relatively high water-extractable fraction.

Fernández-Turiel, J. L.; de Carvalho, W.; Cabañas, M.; Querol, X.; López-Soler, A.

1994-06-01

188

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%

189

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

International Nuclear Information System (INIS)

Fly ash and fine dispersion releases from coal combustion in Greek coal power plants were studied. 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). Risk from the fly ash derives from its escape in particulate form or fine dispersion and from its use as a substitute for cement in concrete. The new data indicate that coal power plants discharge relatively larger quantities of radioactive material into the atmosphere than nuclear power plants of comparable size, during normal operation. (H.K.)

190

A study of fluidized bed solids and fly ash samples to better understand the transformations of the coal ash  

Energy Technology Data Exchange (ETDEWEB)

A special fluidized bed combustion technology, developed in Hungary is described. It is called the hybrid-fluid combustion technology, and has been introduced at the Ajka Power Plant where the CaO content of the ash in local coals is high. A thermogravimetric balance and mass spectrometry was used to study the bed solids and fly-ash samples from the hybrid-fluid boiler, in order to understand the connections between sulphur, lime and carbon compounds contents and their reactions.

Remenyi, K.; Horvath, F.

1993-01-01

191

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

192

Electrokinetics and X-ray diffraction studies on coal and associated ash from Talcher coalfield  

Energy Technology Data Exchange (ETDEWEB)

Electrokinetic and X-ray diffraction studies have been carried out on two non-coking coal samples from Lingaraj and Jagannath mines of Talcher coalfields, Orissa. The measurements were made separately on the hand picked coal and the ash obtained by low temperatures heating. The effects of temperature, acid, alkali and different alcohols on surface of two coal samples were studied. The zeta potential values show some what complex behaviour due to the presence of impurities. The electrokinetic mobility of the coals were found to be minimum in the presence of ethyl alcohol, which may be due to reduction of carboxylic (-COOH) and phenolic (-OH) groups on the coal surface. The ash materials mostly contain silica and alumina and their electrokinetic behaviour were similar to clay minerals. The X-ray diffraction studies have shown the presence of minerals such as quartz, hematite, illite, orthoclase, mica etc. in the coal ash. 8 refs., 7 figs., 3 tabs.

Das, B.; Biswal, S.K.; Prakash, S.; Reddy, P.S.R.; Sastri, S.R.S. [Regional Research Laboratory, Bhubaneswar (India)

2002-07-01

193

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2001-07-01

194

Electrostatic beneficiation of coal fly ash utilizing triboelectric charging with subsequent electrostatic separation  

Energy Technology Data Exchange (ETDEWEB)

A triboelectrostatic separation system for removing unburned carbon from coal fly ash is designed and evaluated. Fly ash from a coal-fired power plant is used in concrete. Unfortunately, unburned carbon in coal fly ash absorbs some of the other additives and reduces the concrete strength. This paper investigates a dry triboelectrostatic process to separate unburned carbon from coal fly ash and utilize it in economically valuable products. The laboratory-scale triboelectrostatic separation system consists of a particle feeding system, a tribocharger, a separation chamber, and collection systems. Particles of unburned carbon and fly ash can be given positive and negative surface charges, respectively, with a copper tribocharger due to differences in the work function values of the particles and the tribocharger, and can be separated by passing them through an external electric field. Results showed that fly ash recovery was strongly dependent on the electric field strength and the particle size. 70 wt% of fly ash containing 6.5 wt% of carbon contents could be recovered at carbon contents below 3%. The triboelectrostatic separation system shows potential as an effective method for removing unburned carbon from coal fly ash.

Lee, J.K.; Kim, S.C. [Pusan National University, Pusan (Republic of South Korea). School of Mechanical Engineering

2001-06-01

195

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)

196

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

International Nuclear Information System (INIS)

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

197

Combined adsorption and oxidation mechanisms of hydrogen sulfide on granulated coal ash.  

Science.gov (United States)

Hydrogen sulfide is highly toxic to benthic organisms and may cause blue tide with depletion of dissolved oxygen in water column due to its oxidation. The purpose of this study is to reveal the combined adsorption and oxidation mechanisms of hydrogen sulfide on granulated coal ash that is a byproduct from coal electric power stations to apply the material as an adsorbent for hydrogen sulfide in natural fields. Sulfur species were identified in both liquid and solid phases to discuss removal mechanisms of the hydrogen sulfide with the granulated coal ash. Batch experiments revealed that hydrogen sulfide decreased significantly by addition of the granulated coal ash and simultaneously the sulfate ion concentration increased. X-ray absorption fine structure analyses showed hydrogen sulfide was adsorbed onto the granulated coal ash and successively oxidized by manganese oxide (III) contained in the material. The oxidation reaction of hydrogen sulfide was coupling with reduction of manganese oxide. On the other hand, iron containing in the granulated coal ash was not involved in hydrogen sulfide oxidation, because the major species of iron in the granulated coal ash was ferrous iron that is not easily reduced by hydrogen sulfide. PMID:22487226

Asaoka, Satoshi; Hayakawa, Shinjiro; Kim, Kyung-Hoi; Takeda, Kazuhiko; Katayama, Misaki; Yamamoto, Tamiji

2012-07-01

198

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)

199

Properties of coal ash mixtures and their use in highway embankments  

OpenAIRE

Class F fly ash and bottom ash are the solid residue by-products produced by coal-burning electric utilities. They are usually disposed of together as a waste in utility disposal sites with a typical disposal rate of 80% fly ash and 20% bottom ash. The fly and bottom ash accumulated daily in disposal areas have been a significant concern to utility companies, and is fast becoming a social problem. Direct use of these materials in construction projects consuming large volumes of materials, suc...

Kim, Bumjoo

2003-01-01

200

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.)

201

Radioactive substances in fly ash from coal-fired power plants  

International Nuclear Information System (INIS)

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

202

Coal ash disposal manual: second edition. Final report  

Energy Technology Data Exchange (ETDEWEB)

Of the approximately 70 million tons of fly ash, bottom ash, and boiler slag produced by United States utilities in 1978, only 24% was used. The rest was placed in storage or disposal areas. This manual was developed to provide reference information for ash disposal. It is intended to aid in the selection and operation of ash disposal systems with respect to cost considerations and operation of ash disposal systems with respect to cost considerations and current governmental regulations by furnishing specific disposal criteria, where available, and by outlining methodologies for decision making and cost estimating. Specific topics covered include site selection methodology; ash physical and chemical properties; current disposal philosophies; possible governmental regulations affecting new ash disposal sites; conceptual design of ash disposal systems and estimates of ash quantities; case studies of existing ash disposal sites; monitoring; site reclamation; and cost estimating. References covering these topics and ash disposal site design are included.

Bahor, M.P.; McLaren, R.J.; Niece, J.E.; Pedersen, H.C.

1981-10-01

203

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

Science.gov (United States)

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

204

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)

205

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

206

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

OpenAIRE

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

Denise Alves Fungaro; Mariza Bruno

2008-01-01

207

Use of gravity fractionation techniques for assessing slagging and fouling potential of coal ash  

Energy Technology Data Exchange (ETDEWEB)

This paper describes a novel approach towards a fundamental understanding of ash deposit phenomena and describes a laboratory bench-scale technique for assessing the slagging and fouling potentials of mineral matter in coal in a boiler firing pulverized fuel. The technique consists of a gravity fractionation of pulverized coal so that the ash can be analyzed in groups of particles that are capable of unique behaviour in the boiler.

Borio, R.W.; Narciso, R.R.

1979-10-01

208

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

OpenAIRE

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

Nugteren, H. W.

2010-01-01

209

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

Directory of Open Access Journals (Sweden)

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.

VESNA M. KALJEVIC

2003-01-01

210

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

OpenAIRE

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...

Mene?ndez, E.; A?lvaro, A. M.; Argiz, C.; Parra, J. L.; Moragues, A.

2013-01-01

211

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...

212

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2005-07-01

213

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

214

Radiological impact of coal ash from the power plants in Hong Kong  

International Nuclear Information System (INIS)

Samples of coal, furnace bottom ash and pulverised fly ash were collected from the two electric companies in Hong Kong. The samples were collected over a period of 1 year and therefore they were representative of the annual consumption of coal as well as the annual production of the ash. Special procedures were taken to separately burn the coal bought from different places so that the origins of the ash samples are traceable. The radionuclide contents, radon emanating fraction and porosity of the samples were measured. Mathematical models were then used to evaluate the radiological hazard of the ash samples when used in the building industry. Both the ? and radon exposures due to the coal ash loaded concrete in buildings are not much different from that due to unloaded concrete. External ? dose rate and 222Rn concentration at the centre of an uncovered ash lagoon are estimated to be 0.165 ?Gy h-1 and 2.9 Bq m-3, respectively, again not much different from the local background. On the other hand, the committed effective dose due to inhalation of PFA of about 7.1 x 108 B ?S?, where B is the PFA loading in air, can be an important source of exposure if resuspension of ash particles is not properly controlled. (author)

215

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

Directory of Open Access Journals (Sweden)

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.

M. M. Chagga

2011-12-01

216

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)

217

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

218

An experimental study of the effect of coal blending on ash deposition  

Energy Technology Data Exchange (ETDEWEB)

In this study, deposition experiments with well characterized samples of Australian black coals and blends were conducted in a laminar drop-tube furnace to assess the blends behavior and their potential to form ash deposits. The results comparison between the blends and single coals shows that the blends behavior was not additive in nature. Some blends were developing thicker ash deposit layer with a maximum thickness higher than 700 {mu}m comparing to a thickness of 300 {mu}m for the source coals, whereas, other blends have a lower potential to form ash deposits. Therefore, the coal blends performance may not be the same as that of the source coals with same bulk composition. Three techniques were used to explain the trends of the deposition experiments. 14 figs., 1 tab.

A. Rushdi; A. Sharma; R. Gupta [University of Newcastle, Callaghan, NSW (Australia). Cooperative Research Centre for Coal in Sustainable Development (CCSD)

2003-07-01

219

Ash bed level control system for a fixed-bed coal gasifier  

Science.gov (United States)

An ash level control system is provided which incorporates an ash level meter to automatically control the ash bed level of a coal gasifier at a selected level. The ash level signal from the ash level meter is updated during each cycle that a bed stirrer travels up and down through the extent of the ash bed level. The ash level signal is derived from temperature measurements made by thermocouples carried by the stirrer as it passes through the ash bed and into the fire zone immediately above the ash bed. The level signal is compared with selected threshold level signal to determine if the ash level is above or below the selected level once each stirrer cycle. A first counter is either incremented or decremented accordingly. The registered count of the first counter is preset in a down counter once each cycle and the preset count is counted down at a selected clock rate. A grate drive is activated to rotate a grate assembly supporting the ash bed for a period equal to the count down period to maintain the selected ash bed level. In order to avoid grate binding, the controller provides a short base operating duration time each stirrer cycle. If the ash bed level drops below a selected low level or exceeds a selected high level, means are provided to notify the operator.

Fasching, George E. (Morgantown, WV); Rotunda, John R. (Fairmont, WV)

1984-01-01

220

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

221

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...

222

Surface studies of coal, oil, and coal-oil-mixture ash using auger electron spectroscopy and solvent leaching techniques  

International Nuclear Information System (INIS)

Fly ash produced by the combustion of coal, oil, and a coal-oil mixture have been studied by Auger electron spectroscopy and solvent leaching techniques. The Auger data indicate that the surface concentration of the metal ions Na, Fe, Mg, Ni, V, and Al as well as S and C increases on going from coal to coal-oil mixture and oil ash. The relative surface enrichments of oil and coal-oil-mixture ash are consistent with a simple model of the ash-formation process, and the results confirm that several toxic metals are significantly enriched on the surface of the ash particles. The Auger data are compared to HCl and tris buffer leachate composition analyses, and in neither case does the leachate give an accurate representation of the surface composition. HCl apparently dissolves large oxide deposits and thus overestimates the surface concentrations of Fe, Al, and V. Conversely, several metallic ions are essentially insoluble in neutral aqueous solutions, so their surface concentration is underestimated by the tris leachate

223

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)

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.

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

2014-01-01

224

An economic study of clean coal with 34% ash content vis-a-vis raw coal (unwashed) and imported coal for power generation in India  

Energy Technology Data Exchange (ETDEWEB)

The Chari Committee submitted its report to Planning Commission in 1996, in which a comparison had been made on the economics of the use of imported coal versus F grade coal from Kalinga opencast mine of Talcher coalfield, by Tamil Nadu State Electricity Board at its power station located in Chennai. In this paper, with relevant change in that report with respect to present situation, the elements of cost of washed coal by beneficiation of F grade coal to the level of 34% ash has been revised. This study has been done to draw a comparison of clean coal with 34% ash content (washery at power plant end) vis-a-vis raw coal (unwashed) and imported coal regarding the cost of generating 1 kWh energy, taking into account all the factors. 2 refs., 6 tabs.

Mukhopadhyay, S. [B.E. College (Deemed University), Howrah (India). Dept. of Mining and Geology

2003-02-01

225

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in english 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.

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

2012-03-01

226

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

Directory of Open Access Journals (Sweden)

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.

MUHAMMAD ISHAQ

2012-03-01

227

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)

228

Utilization of coal fly ash in solidification of liquid radioactive waste from research reactor.  

Science.gov (United States)

In this study, the potential utilization of fly ash was investigated as an additive in solidification process of radioactive waste sludge from research reactor. Coal formations include various percentages of natural radioactive elements; therefore, coal fly ash includes various levels of radioactivity. For this reason, fly ashes have to be evaluated for potential environmental implications in case of further usage in any construction material. But for use in solidification of radioactive sludge, the radiological effects of fly ash are in the range of radioactive waste management limits. The results show that fly ash has a strong fixing capacity for radioactive isotopes. Specimens with addition of 5-15% fly ash to concrete was observed to be sufficient to achieve the target compressive strength of 20 MPa required for near-surface disposal. An optimum mixture comprising 15% fly ash, 35% cement, and 50% radioactive waste sludge could provide the solidification required for long-term storage and disposal. The codisposal of radioactive fly ash with radioactive sludge by solidification decreases the usage of cement in solidification process. By this method, radioactive fly ash can become a valuable additive instead of industrial waste. This study supports the utilization of fly ash in industry and the solidification of radioactive waste in the nuclear industry. PMID:24638274

Osmanlioglu, Ahmet Erdal

2014-05-01

229

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

Science.gov (United States)

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

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

2014-10-01

230

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)

231

Speciation of Chromium in Feed Coals and Ash Byproducts from Canadian Power Plants Burning Subbituminous and Bituminous Coals  

Energy Technology Data Exchange (ETDEWEB)

The chromium species in the feed coals and ash byproducts from seven Canadian coal-fired power plants that were burning local subbituminous or bituminous coals with sulfur contents in the range of 0.30-3.5 wt % have been examined using Cr X-ray absorption near-edge spectroscopy (XANES). Chromium in the Canadian feed coals is always found as Cr{sup 3+} but generally has a dual occurrence, as Cr{sup 3+} is distributed to varying degrees between the clay mineral illite (Cr3+/illite) and a poorly crystallized chromium oxyhydroxide (CrOOH) phase associated with the organic fraction. In two subbituminous feed coals from Alberta, chromium is present largely as Cr{sup 3+}/illite, whereas in two other such coals, it is present predominantly as CrOOH. Chromium in a low-sulfur (0.50 wt %) bituminous feed coal from Alberta is found mostly as Cr{sup 3+}/illite, whereas for feed coals from Nova Scotia with high sulfur contents (2.60-3.56 wt %), chromium is distributed between both Cr{sup 3+}/illite and CrOOH. Very little chromium was found in the limestone used in a fluidized-bed combustor. The chromium species in most bottom ash samples from all seven combustion units is predominantly, if not entirely (>95%), Cr{sup 3+} associated with aluminosilicate phases. Chromium speciation for subbituminous electrostatic precipitator (ESP) fly ash is mostly Cr{sup 3+} (>95%), but in some cases, it is slightly less (>80%) and varies by sampling location at the plant. Chromium in fly ash from the combustion of bituminous feed coals is predominantly (>95%) Cr3+. A unique species of chromium found in one feed coal and an unrelated fly ash is metallic chromium (Cr0), similar to that in stainless steel. The occurrence of this form of chromium in these materials indicates contamination from machinery, such as the coal milling machine or possibly wearing down of stainless steel parts by the coal or ash. The observation of this unexpected contamination demonstrates the power and usefulness of X-ray absorption fine-structure (XAFS) spectroscopy for speciation determination.

Goodarzi,F.; Huggins, F.

2005-01-01

232

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

233

The geochemistry and bioreactivity of fly-ash from coal-burning power stations.  

Science.gov (United States)

Fly-ash is a byproduct of the combustion of coal in power stations for the generation of electricity. The fly-ash forms from the melting of incombustible minerals found naturally in the coal. The very high coal combustion temperatures result in the formation of microscopic glass particles from which minerals such as quartz, haematite and mullite can later recrystallize. In addition to these minerals, the glassy fly-ash contains a number of leachable metals. Mullite is a well-known material in the ceramics industry and a known respiratory hazard. Macroscopically mullite can be found in a large range of morphologies; however microscopic crystals appear to favour a fibrous habit. Fly-ash is a recognized bioreactive material in rat lung, generating hydroxyl radicals, releasing iron, and causing DNA damage. However, the mechanisms of the bioreactivity are still unclear and the relative contributions of the minerals and leachable metals to that toxicity are not well known. PMID:19604058

Jones, Timothy; Wlodarczyk, Anna; Koshy, Lata; Brown, Patrick; Shao, Longyi; BéruBé, Kelly

2009-07-01

234

Petrology of feed coals and chars in ESP fly ashes as related to mercury retained in pulverized coal-fired power plants  

Energy Technology Data Exchange (ETDEWEB)

The maceral content of feed coals used in power plants in Canada was determined using reflected light microscope. The total mercury content of feed coals, bottom ash, and fly ashes was also determined along with carbon content of bottom and fly ash. The results indicate that the fly ash with higher carbon content has higher mercury content. The fraction of mercury in the ash (%) is greater for a coal deposited in a brackish water environment. This is due to the higher inertinite content of coal deposited in a brackish water environment. The data show that elevated inertinite (natural char) in feedstock coal equates to higher unburned carbon in ESP ashes and to enhanced capture of mercury in ESP ashes. The nature of the char found in the fly ash is also important and that char formed from vitrinite (vitrinitic char) was able to capture mercury. Results of mercury monitoring in Canadian power plants burning pulverized coal with high inertinite content show greater mercury captured by ESP. Therefore, it may be possible to reduce mercury emissions at other coal-fired power plants if such high inertinite coals can be used or if high inertinite coal can be blended with typically used coal. 21 refs., 5 figs., 2 tabs.

F. Goodarzi; D. Rose [Natural Resources Canada (Canada). Geological Survey of Canada - Calgary Division

2003-07-01

235

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

Science.gov (United States)

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

Montes-Hernandez, G; Pérez-López, R; Renard, F; Nieto, J M; Charlet, L

2009-01-30

236

Anion exchange method for the sequential determination of uranium, thorium and lead-210 in coal and coal ash  

International Nuclear Information System (INIS)

A radiochemical procedure is presented for the sequential determination of uranium isotopes, thorium isotopes, and 210Pb in coal and coal ash. This procedure consists of dry ashing the sample, a nitric-hydrofluoric acid dissolution, removal of iron with ether extractions, and separation of the elements of interest by anion exchange chromatography. Uranium and thorium isotopes are measured by alpha spectrometry, while 210Pb is measured by beta counting its daugther activity, 210Bi. For 10 g coal samples and 1 g ash samples, the chemical yields for the radioactivities measured were 70-80%, and the relative standard deviations for replicate analyses were generally less than 9%. The deviations of the means from the reference values were within the combined errors of each and were usually less than +-5%. Minimum detectable activities were about 0.02 pCi for uranium and thorium isotopes and 0.2 pCi for 210Pb. (author)

237

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)

238

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

OpenAIRE

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...

Kovács Ferenc; Mang Béla

2002-01-01

239

Apparatus and method for direct measurement of coal ash sintering and fusion properties at elevated temperatures and pressures  

Science.gov (United States)

A high-pressure microdilatometer is provided for measuring the sintering and fusion properties of various coal ashes under the influence of elevated pressures and temperatures in various atmospheres. Electrical resistivity measurements across a sample of coal ash provide a measurement of the onset of the sintering and fusion of the ash particulates while the contraction of the sample during sintering is measured with a linear variable displacement transducer for detecting the initiation of sintering. These measurements of sintering in coal ash at different pressures provide a mechanism by which deleterious problems due to the sintering and fusion of ash in various combustion systems can be minimized or obviated.

Khan, M. Rashid (Morgantown, WV)

1990-01-01

240

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.)

241

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)

242

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

OpenAIRE

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 ...

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

2011-01-01

243

Preparation of low-ash products from Slovak lignitic coals – material balance  

Directory of Open Access Journals (Sweden)

Full Text Available A preparation of low-ash coal products was performed with the aim to obtain asuitable charge for the extraction following processes of organic substances. Thus, for this purpose, the coal feeds from two collieries, namely Záhorie and Nováky were washed in the water-only cyclone with a diameter of 150 mm. The vortex finder and apex diameters were 68 mm and 14.6 mm, respectively. The cone consisting of three angle sections 135°-75°-20° was applied. The products obtained on the overflow of the cyclone were decantated to remove the rests of slurries. In such a way, washed coals with the ash content in the dry matter of 5.44 was prepared from lignite of Záhorie. Similarly, as to coal from Nováky the ash content of 9.21 % was achieved.

Anton Zubrík

2006-12-01

244

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

Science.gov (United States)

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

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

2014-03-01

245

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

Directory of Open Access Journals (Sweden)

Full Text Available Recently, the worldwide supply of rare earth element (REE resources will be severely restricted. On the other hand, coal fly ash particles emitted from coal-fired electric power plants contain relatively high concentrations of REEs. The contents of REEs in coal fly ash are regularly several hundreds of ppmw. In order to extract and recover REEs from coal fly ash particles, as a first step, we have investigated their dissolution behavior in a dilute H2SO4 solvent. The REE content of coal fly ash specimens has been precisely determined, and their presence in the ash component of the original coal and their enrichment in coal fly ash particles during coal combustion have been suggested. REEs in coal fly ash dissolve gradually in H2SO4 over time, and this implies two types of occurrences of the REEs in coal fly ash particles. By applying the unreacted core model to the dissolution behavior of REEs in a H2SO4 solvent, we can explain both types of occurrences.

Shunsuke Kashiwakura

2013-05-01

246

Coal Ash Resources Research Consortium. Annual report and selected publications, 1 July 1992--30 June 1993  

Energy Technology Data Exchange (ETDEWEB)

The Coal Ash Resources Research Consortium (CARRC, pronounced cars), formerly the Western Fly Ash Research, Development, and Data Center (WFARDDC), has continued fundamental and applied scientific and engineering research focused on promoting environmentally safe, economical use of coal combustion fly ash. The research tasks selected for the year included: (1) Coal Ash Properties Database Maintenance and Expansion, (2) Investigation of the High-Volume Use of Fly Ash for Flowable Backfill Applications, (3) Investigation of Hydrated Mineralogical Phases in Coal Combustion By-Products, (4) Comparison of Department of Transportation Specifications for Coal Ash Utilization, (5) Comparative Leaching Study of Coal Combustion By-Products and Competing Construction Materials, (6) Application of CCSEM for Coal Ash Characterization, (7) Determination of Types and Causes of Efflorescence in Regional Concrete Products, and (8) Sulfate Resistance of Fly Ash Concrete: A Literature Review and Evaluation of Research Priorities. The assembly of a database of information on coal fly ash has been a focus area for CARRC since its beginning in 1985. This year, CARRC members received an updated run time version of the Coal Ash Properties Database (CAPD) on computer disk for their use. The new, user-friendly database management format was developed over the year to facilitate the use of CAPD by members as well as CARRC researchers. It is anticipated that this direct access to CAPD by members as well as CARRC researchers. It is anticipated that this direct access to CAPD by members will be beneficial to each company`s utilization efforts, to CARRC, and to the coal ash industry in general. Many additions and improvements were made to CAPD during the year, and a three-year plan for computer database and modeling related to coal ash utilization was developed to guide both the database effort and the research effort.

Pflughoeft-Hassett, D.F.; Dockter, B.A.; Eylands, K.E.; Hassett, D.J.; O`Leary, E.M.

1994-04-01

247

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)

248

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

OpenAIRE

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...

Michalíková Františka; Krinická Ivana; Kolesárová Miroslava; Sisol Martin; Praš?áková Mária

2010-01-01

249

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...

250

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1997-04-28

251

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

252

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.)

253

Continuous quality measurement of raw coal by ash content radiometry - experiences from CAM 500 equipment operation  

Energy Technology Data Exchange (ETDEWEB)

Explains design and performance of the CAM 500 brown coal ash content analyzer which continuously monitors uncrushed coal (0 to 500 mm grain size) passing on a textile reinforced conveyor belt. The CAM 500 is installed at the Berzdorf surface mine, GDR, which supplies coal to the Hagenwerder power plant. Two additional units are installed at the Welzow-Sued surface mine, which provides coal to the Schwarze Pumpe gas plant. The CAM 500 equipment has been operating in both mines since 1986. Equipment configuration, means of installation at belt conveyors, display at central monitoring stands in mines, accuracy and reliability are described. The instruments are regarded as indispensable for securing high quality, low ash coal supply to industrial consumers. 4 refs.

Reichardt, H.; Haugk, U.; Rinza, H.; Grueneberg, M.; Schubert, E. (VE Braunkohlenkombinat, Senftenberg (German Democratic Republic))

1990-06-01

254

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

International Nuclear Information System (INIS)

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

255

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

Science.gov (United States)

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

Chakraborty, Rajarshi; Mukherjee, Anita

2011-02-01

256

Characterisation of coal fly ash from thermal power plants in India  

International Nuclear Information System (INIS)

Fly ash collected from 22 thermal power stations spread over the country were analysed for various elements such as As, Ca, Ce, Co, Cr, Cu, Eu, fe, Hf, K, La, Lu, Mn, Na, Ni, Pb, Rb, Se, Sb, Sc, Sm, Sr, Ti, V, Yb, Zn etc. using energy dispersive X-ray fluorescence (EDXRF) and instrumental neutron activation analysis (INAA) methods. The results show that the concentrations of these elements vary widely but are within the normal range of values cited in the literature. In India, apart from coal, lignite is also burnt in the power plants. The ash content of lignite is only 7%. Most of the trace elements except sulphur get enriched (in terms of weight concentrations) in the process of combustion. The concentration of trace elements are 1.5 to 3 times in the lignite ash as compared to coal fly ash. Inter element correlations in the fly ash samples showed associations of Ti with Fe, Si with K and Cu, Zn with Pb, K with Rb and Ca with Sr. The fly ash samples in two sizes 53 ?m). Leaching of fly ash was also carried out by agitating the fly ash at pH 4.0 for 24 hrs. The residues were also analysed for major and trace elements. (author). 7 refs., 4 tabselements. (author). 7 refs., 4 tabs

257

The role of ammonia on mercury leaching from coal fly ash.  

Science.gov (United States)

The Federal Clean Air Interstate Rule issued in March 2005 will result in many power plants employing ammonia-based technologies to control NO(x) emission. The Clean Air Mercury Rule, issued at the same time, will encourage many power plants to use various technologies to remove mercury from flue gas, generating fly ashes that contain elevated concentrations of mercury. Ammonia forms relatively strong complexes with mercury compared to most other cationic elements and, therefore, may change the leaching characteristics of mercury. Understanding the impact of ammonia on the leaching of mercury from fly ash is critical in predicting the potential environmental impact of future fly ash. Batch methods were used to investigate the ammonia impact on mercury leaching from fly ash under different pH conditions. The results indicated that mercury leaching without external ammonia addition is not significant. However, ammonia addition increased mercury leaching in the alkaline pH range, due to the formation of less adsorbable mercury-ammonia complexes. Washed ash released more mercury than the raw ash if the ammonia concentration is the same, mainly due to the dissolution of some ash components during washing which exposed more mercury on ash surface. Mercury adsorption data indicated that more than 90% of available mercury was adsorbed by fly ash even in the presence of 1000 mg l(-1) ammonia addition. PMID:17604819

Wang, Jianmin; Wang, Tian; Mallhi, Harmanjit; Liu, Yu; Ban, Heng; Ladwig, Ken

2007-11-01

258

Effect of coal quality on maintenance costs at utility plants. Final report. [Effect of ash and sulfur content of coal  

Energy Technology Data Exchange (ETDEWEB)

In an attempt to determine if correlation exists between coal quality, as measured by its ash and sulfur contents, and the maintenance cost at utility plants, an examination was made of the actual maintenance cost experience of selected portions of five TVA coal-fired power plants as a function of the fuel quality consumed during an extended period of time. The results indicate that, according to our decision rules developed in compliance with accepted statistical practices, correlation does exist in many portions of the coal-fired plants for which sufficient maintenance cost records were available. The degree of correlation varies significantly among the individual portions of a particular plant as well as among the various plants. However, the indicators are sufficient to confirm that a change (within the design constraints of the unit) in the ash and/or sulfur content of the coal being consumed by a utility boiler will have a proportionate effect on the maintenance cost at the plant. In the cases examined, each percent variation in ash content could have a monetary effect of from $0.05 to $0.10 per ton of coal consumed. Similarly, each percent variation in sulfur content could influence maintenance costs from $0.30 to $0.50 per ton of coal. Since these values are based on preliminary analysis of limited data, they must be approached with caution and not removed from the context in which they are presented. However, if borne out by further study, the potential magnitude of such savings may be sufficient to justify the acquisition of superior coal supplies, either by changing the source and/or using preparation to obtain a lower ash and sulfur fuel.

Holt, E.C. Jr.

1980-06-01

259

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

260

The governance of coal ash pollution in post-socialist times : power and expectations.  

OpenAIRE

The coal energy sector in Bosnia and Herzegovina (BiH) represents both a significant economic hope and a considerable environmental threat for the country. One of the major problems of the coal industry is the disposal of large amounts of coal combustion residues. RECOAL was an EU-supported project (2005-7) whose objective was to develop remediation solutions for coal ash disposal (CAD) sites in BiH. Most of RECOAL's environmental fieldwork was based around TEP in the municipality of Tuzla, o...

Casta?n Broto, V.; Carter, C.; Elghali, L.

2009-01-01

261

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

Science.gov (United States)

On December 22, 2008 a dike containing coal fly ash from the Tennessee Valley Authority Kingston Fossil Plant near Kingston Tennessee USA failed and resulted in the largest coal ash spill in U.S. history. Coal ash, a by-product of coal combustion, is known to contain multiple contaminants of concern, including arsenic and selenium. The purpose of this study was to investigate species differences in the bioaccumulation of arsenic and selenium and potential factors contributing to these differences (i.e., trophic dynamics and gut pH) in the vicinity of the Kingston coal ash spill. Elevated levels of arsenic and selenium were observed in various tissues of largemouth bass, white crappie, bluegill and redear sunfish from sites associated with the Kingston coal ash spill. Highest concentrations of selenium were found in redear sunfish with liver concentrations as high as 24.83mg/kg dry weight and ovary concentrations up to 10.40mg/kg dry weight at coal ash-associated sites. Investigations into the gut pH and trophic dynamics of redear sunfish and bluegill demonstrated a large difference in the gut physiology between these two species. Redear sunfish stomach and intestinal pH was found to be 1.1 and 0.16 pH units higher than in bluegill, respectively. In addition, fish from coal ash-associated sites showed enrichment differences ((15)N and (13)C) compared to no ash sites, indicating differences in food web dynamics between sites. These results imply the incorporation of coal ash-associated compounds into local food webs and/or a shift in diet at ash sites compared to the no ash reference sites. Based on these results, further investigation into a broader food web at ash-associated sites is warranted. PMID:22947506

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

2012-11-01

262

Speciation of Arsenic in Canadian Subbituminous and Bituminous Feed Coals and their Ash Byproducts  

Energy Technology Data Exchange (ETDEWEB)

The arsenic species in the feed coals and ash byproducts from seven Canadian power plants (including one with a fluidized-bed combustor) that were burning local sub-bituminous and bituminous coals with sulfur contents in the range of 0.30-3.5 wt % have been examined using As X-ray absorption fine structure (XAFS) spectroscopy. The feed coals can be grouped based on their contents of arsenic associated with pyrite (As/pyr) and as As{sup 3+} and As{sup 5+} (arsenate) species. The arsenic species in sub-bituminous feed coals with low sulfur (0.22-0.38 wt %) and arsenic (1.6-2.2 mg/kg) contents consist of {approx}50% As{sup 3+} and {approx}50% As{sup 5+}, whereas those with moderate sulfur (0.50 wt %) and arsenic (3.63 mg/kg) contents consist of 84% As/pyr, 7% As3+, and 9% As{sup 5+}. In bituminous feed coal with low sulfur (0.40 wt %) and arsenic (4.39 mg/kg) contents, the arsenic speciation consists of 34% As/pyr, 12% As{sup 3+}, and 54% As{sup 5+}, and for those with high sulfur (2.60-3.56 wt %) and arsenic (54-84 mg/kg) contents, it consists of 77%-82% As/pyr and 18%-23% As{sup 5+}. The bottom ash produced from sub-bituminous feed coals with low sulfur and arsenic contents consists of 10%-20% As3+ and 80%-90% As5+, and for moderate sulfur (0.50 wt %) and arsenic (3.63 mg/kg), the arsenic speciation consists of 5% As/pyr, 10% As{sup 3+} and 85% As{sup 5+} as arsenate. For bituminous feed coals with low sulfur and arsenic contents, the bottom ash is entirely As{sup 5+}, whereas for coals with high sulfur and arsenic contents, the bottom ash consists of 10%-15% As{sup 3+} and 85%-90% As{sup 5+}; and for the fluidized-bed combustor, the bottom ash is entirely As{sup 5+} arsenate. The species of arsenic in fly ash from sub-bituminous and bituminous coals are mostly arsenate (As5+), possibly in part incorporated in the glass matrix, and remains the same for coarse- and fine-grained electrostatic precipitator (ESP), baghouse, and stack-emitted ashes. The only difference between the ESP and baghouse fly ash is the higher amount of crystalline arsenates in the hopper fly ash. Neither the sulfur content nor the pyrite content of the feed coal seems to influence the speciation of arsenic, because virtually all of the arsenic in fly ash samples from high-sulfur coal is in the form of arsenate (As{sup 5+}). However, arsenic (mostly as As{sup 5+}) in these fly ashes is found to be very surface-enriched, because the amount measured by XPS decreases from >3 wt % to <0.8 wt % in the first few atomic layers. The presence of stable calcium or transition-metal iron hydroxyl arsenate hydrate [(M{sup 2+}){sub 2}Fe{sub 3}(AsO{sub 4}){sub 3}(OH){sub 4}{center_dot}10H{sub 2}O] complexes, as determined by X-ray diffractometry, in the fly ash produced from high-sulfur/pyrite feed coals indicates that some of the arsenic might be captured by calcium and iron compounds.

Goodarzi,F.; Huggins, F.

2005-01-01

263

The valuation of trends flotability of non-burnt coal residuals /combustibe components from fly ash.  

Directory of Open Access Journals (Sweden)

Full Text Available Possibilities of the utilisation of energetical wastes in civil engineering applications is limited due to the content of residuals of non-burnt coal, magnetite iron, refined fly ash. The flotation is able to reduce the content of residuals of non-burnt coal in the ashes from coals. The optimum quantity of collector, required time of duration of the process, the number of purifying and control flotations, the percentage of combustible substances in all flotation products are very important flotation parameters. From the point of view of development of combustible components results of fly ashes flotation can be prezent in the flotation concentrate and in the waste after the flotation on the basis their mathematical trend models.

Benková Marta

2004-06-01

264

A novel hollow cathode device for the detection of trace elements in coal ash  

Energy Technology Data Exchange (ETDEWEB)

The hollow cathode plume technique of spectroscopic analysis (HCP) is extended for the detection of trace elements such as arsenic, zinc, cadmium, lead, etc. in coal ash. Introducing a conical inner contour along with internal cooling of the hollow cathode, provides sufficient enhancement of spectral line intensity for the detection of small amounts of trace elements. Using the HCP technique on a coal ash sample supplied by NIST, the relative concentration of As to Zn was found to be within 2% of that obtained by NIST using independent techniques. Although the quantitative determination of the various trace elements in coal ash was beyond the scope of this initial study, ongoing work will establish the general viability of the technique.

Collett, W.L.; Mahajan, S.M.; Ventrice, C.A. (Tennessee Technological University, Cookeville, TN (United States). Dept. of Electrical Engineering)

1993-09-01

265

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)

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.

Wu, Hao; Shafique Bashir, Muhammad

2012-01-01

266

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

267

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...

268

The leaching of major and trace elements from coal ash  

International Nuclear Information System (INIS)

Current knowledge concerning the factors controlling the dissolution of trace elements from fly ash are reviewed. The application of leaching test methods and computer models to predict the leachability of ash are discussed. Current hydrogeochemical models have limited capacity to predict the concentrations of anionic trace elements as a function of time in complex disposal environments. 115 refs., 9 figs., 2 tabs

269

The direct transformation of brown coal ashes into green  

International Nuclear Information System (INIS)

Especially in summer a major amount of dust was emitted from the residual open-pit filled with the ashes from power plants. Between 1984 and 1991 several attempts were made to turn the ash put into green, but they were unsuccessful. It was only the method of the Janssen, Koethen and Geoter (Belgium) companies that brought about a dense green. (orig.)

270

Levels and patterns of polycyclic aromatic hydrocarbons in coal-fired power plant bottom ash and fly ash from Huainan, China.  

Science.gov (United States)

Fly ash and bottom ash samples were collected from a coal-fired power plant located in Anhui province, China. Mineral phases and morphologies of the samples were determined by X-ray diffraction and scanning electron microscopy, respectively. Sixteen polycyclic aromatic hydrocarbon (PAH; 16 compounds specified in United States Environmental Protection Agency Method 610) properties in ash samples were investigated. In fly ashes, ?16PAH (total amount of 16 PAHs) and ?CPAH (total amount of 8 carcinogenic PAHs) levels varied from 0.93 to 2.08 ?g/g and from 0.26 to 0.87 ?g/g, respectively. In bottom ashes, ?16PAH and ?CPAH levels varied from 2.83 to 5.32 and 1.76 to 3.76 ?g/g, respectively. Fly ashes were dominated by medium molecular-weight PAHs and low molecular-weight PAHs, whereas bottom ashes were abundant in 5- and 6-ring PAH species. The CPAHs levels of some ashes, especially bottom ashes, are greater than the limits regulated by several countries, indicating that this type of coal combustion product requires special treatment before landfill. PAH levels and patterns in fly ash were evidently affected by particle size, and total organic content had a closer correlation with PAH content than particle size in bottom and fly ash, which may be due to unburned carbon existing in bottom ash. PMID:23591765

Ruwei, Wang; Jiamei, Zhang; Jingjing, Liu; Liu, Guijian

2013-08-01

271

Laser Induced Breakdown Spectroscopy application for ash characterisation for a coal fired power plant  

International Nuclear Information System (INIS)

The aim of this work was to apply the LIBS technique for the analysis of fly ash and bottom ash resulting from the coal combustion in a coal fired power plant. The steps of presented LIBS analysis were pelletizing of powdered samples, firing with laser and spectroscopic detection. The analysis 'on tape' was presented as an alternative fast sampling approach. This procedure was compared with the usual steps of normalized chemical analysis methods for coal which are coal calcination, fluxing in high temperature plasma, dilution in strong acids and analyzing by means of ICP-OES and/or AAS. First, the single pulse LIBS approach was used for determination and quantification of elemental content in fly ash and bottom ash on the exit of the boiler. For pellet preparation, ash has to be mixed with proper binder to assure the sample resistance. Preparation of the samples (binder selection and pressing/pelletizing conditions) was determined and LIBS experimental conditions optimized. No preparation is necessary in 'on tape' sampling. Moreover, double-pulse approach in orthogonal reheating configuration was applied to enhance the repeatability and precision of the LIBS results and to surpass the matrix effect influencing the calibration curves in case of some elements. Obtained results showed that LIBS responses are comparable to the normalized analytical methods. Once optimized the experimental conditions and features, application of LIBS may be a promising technique for combusBS may be a promising technique for combustion process control even in on-line mode.

272

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)

273

Ecological risk assessment for residual coal fly ash at Watts Bar Reservoir, Tennessee.  

Science.gov (United States)

The Tennessee Valley Authority conducted a Baseline Ecological Risk Assessment (BERA) for the Kingston Fossil Plant ash release site to evaluate potential effects of residual coal ash on biota in Watts Bar Reservoir, Tennessee. The BERA was in response to a release of 4.1 million m(3) of coal ash on December 22, 2008. It used multiple lines of evidence to assess risks for 17 different ecological receptors to approximately 400?000?m(3) of residual ash in the Emory and Clinch rivers. Here, we provide a brief overview of the BERA results and then focus on how the results were used to help shape risk management decisions. Those decisions included selecting monitored natural recovery for remediation of the residual ash in the Emory and Clinch rivers and designing a long-term monitoring plan that includes adaptive management principles for timely adjustment to changing conditions. This study demonstrates the importance of site-specific ecological data (e.g., tissue concentrations for food items, reproductive data, and population data) in complex ecological risk assessments. It also illustrates the value of the US Environmental Protection Agency's (USEPA) data quality objectives process in building consensus and identifying multiple uses of results. The relatively limited adverse effects of this likely worst-case scenario for ash-related exposures in a lotic environment provide important context for the USEPA's new coal combustion residue disposal rules. Integr Environ Assess Manag 2015;11:80-87. © 2014 SETAC. PMID:25346032

Carriker, Neil E; Jones, Daniel S; Walls, Suzanne J; Stojak, Amber R

2015-01-01

274

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

Directory of Open Access Journals (Sweden)

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

Denise Alves Fungaro

2008-12-01

275

Radiological aspects of using coal Ash (Slag) in the building industry  

International Nuclear Information System (INIS)

Application of coal combustion ashes in building materials has been limited by the presence of minor components such as radioactive substances. 226Ra, 232Th, and 40K accumulated in the ash during the burning of the coal may result in significant, several doses of mSv annually. Radon exhalation is usually low, but in some cases a significant dose (5-15 mSv/y) may be calculated upon due to the 222Rn emanating from this kind of building materials. Therefore a radiological survey, classification of these materials is necessary before utilization. (author)

276

Adsorption of Rhodococcus Strain GIN-1 (NCIMB 40340) on Titanium Dioxide and Coal Fly Ash Particles  

OpenAIRE

Rhodococcus strain GIN-1 (NCIMB 40340) can be used to enrich and isolate a titanium-rich fraction from coal fly ash. The gram-positive bacterium was isolated by its ability to adhere strongly and rapidly to suspended particles of pure titanium dioxide or coal fly ash. Adsorption depends on the salt concentration and occurs in seawater. Lowering of the salt concentration or washing of particles with pure water did not, however, cause desorption of the bacteria from TiO2 particles; this was ach...

Shabtai, Y.; Fleminger, G.

1994-01-01

277

Carbon-Enriched coal fly ash as a precursor of activated carbons for SO2 Removal  

OpenAIRE

Carbon-enriched coal fly ash was evaluated in this work as a low-cost adsorbent for SO2 removal from stack gases. The unburned carbon in coal fly ash was concentrated by mechanical sieving and vegetal oil agglomeration. The carbon concentrates were activated with steam at 900ºC in order to develop porosity onto the samples. The performance of these samples in the SO2 abatement was tested in the following conditions: 100ºC, 1000 ppmv SO2, 5% O2, 6% water vapor. A good SO2 remo...

Izquierdo Pantoja, Mari?a Teresa; Rubio Villa, Begon?a

2007-01-01

278

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

Directory of Open Access Journals (Sweden)

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.

Jankovi? M.M.

2011-01-01

279

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)

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.

Argiz, C.

2013-03-01

280

Radiometric method for the continuous determination of the ash content of low-grade coals  

International Nuclear Information System (INIS)

A radiometric method and apparatus have been developed for the continuous determination of the ash content of low-grade coals. The apparatus can be used for continuous measurements in an industrial environment and for the control of an automatic system. The material to be tested is continuously delivered by a screw-feeder through the measuring compartment of the radiometric probe. The ash content determination is based on gamma absorption measurement. Making use of the incrementof gamma reflection the radiometric method allows for the accurate determination of the space-filling and provides for the automatic correction necessary for the ash content determination. (author)

281

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

282

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

Science.gov (United States)

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

283

Characterization of a flying ash stemming from the combustion of the coal  

Science.gov (United States)

In this study, we were interested in the physic - chemical characterization (SEM, BET, X-ray, DTA-TG, and IR) of the flying ashes stemming of the combustion of the coal in the thermal power station of JORF-LASFAR in EL Jadida (Morocco). On the one hand, we deduce from this study that these flying ashes are belonging to the class F Fly ash (according to ASTM standards). The X-ray diffraction shows that the ashes are mainly constituted by the aluminosilicate and the quartz. The thermal analysis (DTA-TG), the IR, and SEM proves the presence of the carbonates of the calcium. On the other hand, after washing the ashes, with the distilled water, an equilibrium of adsorption - desorption of the carbonates was reached after 30 minutes.

Moufti, A.; Brahmi, R.; Garmes, H.; Bensitel, M.; Mountadar, M.

2005-03-01

284

Seeding effect on cocomposting wastewater biosolids with coal fly ash.  

Science.gov (United States)

The seeding effect on fly ash-amended biosolids composting was evaluated by inoculating a mixture of ash and biosolids with seeding materials before composting. These inocula included thermophilic bacteria (Bacillus. brevis, B. coagulans, and B. licheniformis) isolated from the ash-biosolids compost, a commercial decomposter, and recycled biosolids compost. Although the addition of these microbial additives to the ash-biosolids compost improved the population of thermophilic bacteria at the early stage of composting, the improvement was negligible after 4 days of composting. Inoculation with isolated bacterial culture, milk powder, or the decomposter, only, did not effectively improve the decomposition of organic matter compared with those receiving inoculation of both microbial additives and milk powder together. The isolated Bacillus species was as efficient as the commercial decomposter in accelerating the decomposition rate during ash-amended biosolids composting as indicated by the high amounts of carbon dioxide evolved and cumulative weight loss. Ash-biosolids compost inoculated with 15% (dry weight basis) of recycled compost showed a comparable decomposition activity to those inoculated with bacterial culture and the commercial decomposter with milk powder. Taking into consideration the lower operating cost and acceptable decomposition efficiency, recycled biosolids compost seemed to be a promising additive to ash-amended biosolids compost to improve composting efficiency. PMID:11766000

Fang, M; Wong, J W

2001-01-01

285

Microwave digestion for the quantification of inorganic elements in coal and coal ash using ICP-OES.  

Science.gov (United States)

In this paper, microwave digestion conditions have been optimised to achieve complete recoveries for the ash-forming inorganic elements in coal and coal combustion fly ash, during the analysis by inductively coupled plasma optical emission spectroscopy (ICP-OES). The elements analysed include six major (Al, Ca, Fe, K, Mg and Na) and twelve trace (As, Ba, Be, Co, Cr, Cu, Li, Mn, Ni, Pb, Sr and V). Seven reference samples have been tested, including two standard coal references, SRM1632c and SARM19, their corresponding high-temperature ashes (HTAs), and three coal fly ash references, SRM1633c, SRM2690 and BCR38. The recoveries of individual elements in these samples have been examined intensively, as a function of the amount of hydrofluoric acid (HF, 0-2.0 ml), microwave power (900 W vs. 1200 W) and sample mass (0.05 g vs. 0.1 g). As have been confirmed, the recoveries of these individual elements varied significantly with the microwave digestion condition, elemental type and sample property. For the coal references and their HTAs, the use of HF can be ruled out for most of the elements, except K associated with feldspar, Pb and V. In particular, the recovery of Pb in coal is highly sample-specific and thus unpredictable. The majority of elements in fly ash references require the use of 0.1-0.2 ml HF for a complete recovery. Al in fly ash is the only exceptional element which gave incomplete recoveries throughout, suggesting the use of a complementary technique for its quantification. As has proven to be the only element inconsequential of sample type and digestion conditions, achieving complete recoveries for all cases. On the power parameter, using a higher power such as 1200 W is critical, which has proved to be an ultimatum for the recovery of certain elements, especially in fly ash. Halving sample mass from 0.1 g to 0.05 g was also found to be insignificant. PMID:23158332

Low, Fiona; Zhang, Lian

2012-11-15

286

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

OpenAIRE

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...

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

2012-01-01

287

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)

288

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  

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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.

Denise Alves Fungaro

2004-08-01

289

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

Science.gov (United States)

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

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

2015-01-01

290

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

DEFF Research Database (Denmark)

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.

Wu, Hao; Bashir, Muhammad Shafique

2013-01-01

291

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)

292

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

DEFF Research Database (Denmark)

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.

Shafique Bashir, Muhammad; Jensen, Peter Arendt

2012-01-01

293

Removal of arsenic in coal fly ash by acid washing process using dilute H2SO4 solvent.  

Science.gov (United States)

Coal fly ash emitted from coal thermal power plants generally contains tens ppm of arsenic, one of the hazardous elements in coal, during combustion and their elution to soil or water has become a public concern. In this study, the acid washing process developed by the authors was applied to the removal of arsenic from coal fly ash. Laboratory- and bench-scale investigations on the dissolution behavior of arsenic from various coal fly ash samples into dilute H(2)SO(4) were conducted. Arsenic in the coal fly ash samples were dissolved into H(2)SO(4) solutions rapidly. However, its concentrations decreased with an increase in the pH of H(2)SO(4) solution in some cases. The species of arsenic in the dilute H(2)SO(4) was estimated as H(3)AsO(4), and its anionic species was considered to adsorb with the elevation of pH under the presence of ash particle. Such adsorption behavior was enhanced under the presence of Fe ion in the solution. The sufficient removal of arsenic was achieved by controlling pH and avoiding the adsorption of arsenic on the surface of coal fly ash particles, and the elution of arsenic from coal fly ash sample was successfully below the regulation limit. PMID:20570439

Kashiwakura, Shunsuke; Ohno, Hajime; Matsubae-Yokoyama, Kazuyo; Kumagai, Yuichi; Kubo, Hiroshi; Nagasaka, Tetsuya

2010-09-15

294

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-11-15

295

Seeding effect on cocomposting wastewater biosolids with coal fly ash  

Energy Technology Data Exchange (ETDEWEB)

The seeding effect on fly ash-amended biosolids composting was evaluated by inoculating a mixture of ash and biosolids with seeding materials before composting. These inocula included thermophilic bacteria (Bacillus. brevis, B. coagulans, and B. licheniformis) isolated from the ash-biosolids compost, a commercial decomposter, and recycled biosolids compost. Although the addition of these microbial additives to the ash-biosolids compost improved the population of thermophilic bacteria at the early stage of composting, the improvement was negligible after 4 days of composting. Inoculation with isolated bacterial culture, milk powder, or the decomposter, only, did not effectively improve the decomposition of organic matter compared with those receiving inoculation of both microbial additives and milk powder together. The isolated Bacillus species was as efficient as the commercial decomposter in accelerating the decomposition rate during ash-amended biosolids composting as indicated by the high amounts of carbon dioxide evolved and cumulative weight loss. Taking into consideration the lower operating cost and acceptable decomposition efficiency, recycled biosolids compost seemed to be a promising additive to ash-amended biosolids compost to improve composting efficiency.

Fang, M.; Wong, J.W.C. [Hong Kong Baptist University, Hong Kong (China). Dept. of Biology

2001-10-01

296

A novel silica alumina-based backfill material composed of coal refuse and fly ash.  

Science.gov (United States)

In this paper, a systematic study was conducted to investigate a novel silica alumina-based backfill material composed of coal refuse and fly ash. The coal refuse and fly ash had different properties under various thermal activation temperatures (20 °C, 150 °C, 350 °C, 550 °C, 750 °C and 950 °C). It is known that a thermal activation temperature ranging from 20 °C to 950 °C significantly increases the flowability and pozzolanic properties of the coal refuse; however, the flowability of fly ash decreases when the activation temperature is higher than 550 °C because of a severe agglomeration phenomenon on its surface. An optimal design for this backfill material was determined to include an activated portion composed of 5% coal refuse at 750 °C and 15% fly ash at 20 °C. This combination yields the best performance with excellent flowability, a high compressive strength and a low bleeding rate. The microanalysis results corresponded well with the performance tests at different activation conditions. In the coal refuse, kaolinite peaks began to decrease because of their transformation into metakaolin at 550 °C. Chlorite peaks disappeared at 750 °C. Muscovite peaks decreased at 750 °C and disappeared at 950 °C. During this process, muscovite 2M(1) gradually dehydroxylated to muscovite HT. Furthermore, this paper examined the environmental acceptance and economic feasibility of this technology and found that this silica alumina-based backfill material composed of coal refuse and fly ash not only meets EPA requirements but also has several advantages in industry feasibility when compared with hydraulic backfill, rock backfill and paste backfill. PMID:22336582

Yao, Yuan; Sun, Henghu

2012-04-30

297

Desulphurization Characteristic of Industry Alkaline Wastes during Coal Combustion  

Directory of Open Access Journals (Sweden)

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.

Bin Zheng

2009-03-01

298

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.

299

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

International Nuclear Information System (INIS)

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

300

Fast neutron activation analysis of brown coal samples for silica and ash  

International Nuclear Information System (INIS)

The fast neutron activation technique was applied to bulk samples of brown coal. The determination of silicon is based on the reaction 28Si(n,p) 28Al by counting the 1.78 MeV pulses (t1/2 = 2.3 min). The influence from the thermal neutron reaction 27Al(n,?) 28Al is reduced by a Cd-metal shielding which surrounds the sample holder. The ash content determination is based on the correlation between the ash and silica content or between the ash and the sum of the aluminia and silica contents. In the second case the measurement is accomplished without Cd-shielding. The accuracies (1 S.D) of the silica and ash content determination were 0.15 % SiO2, 0.56 % ash and 3.2 % ash for silica and ash contents of the samples in the range of 0.1 - 4 %, 5 - 17 % and 12 - 81 % ash, respectively. (author)

301

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

1993-11-01

302

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

Directory of Open Access Journals (Sweden)

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

Štefan Jakabský

2010-11-01

303

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

Scientific Electronic Library Online (English)

Full Text Available SciELO South Africa | Language: English Abstract in english 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.

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

2010-10-01

304

Biological assessment of a coal-ash contaminated stream using pleurocerid snails  

International Nuclear Information System (INIS)

To assess the biological impacts of coal-ash on a stream community, a mark-release-recapture study was conducted with two pleurocerid snails, Elimia sp. and Pleurocera sp. Seven hundred snails of each species were collected from a reference stream, tagged, weighed, and released into a snail-free, coal-ash contaminated stream (McCoy Branch) in eastern Tennessee. Snails were also caged in the stream for one week; all remained alive. Four weeks after the release, only 14% of each species were recovered; all were downstream from the release point. Recovered Pleurocera had higher ammonium excretion rates than those in the reference stream. Growth rates were negligible. Recovered snails were re-released into McCoy Branch and recovered again four weeks later. Less than 2% of the total snails were recovered; again, all downstream. Both species had extremely low ammonium excretion rates possibly because of a depletion of protein reserves, but respiration rates were similar to those in a reference stream. The recovered snails had little or no growth and new shell growth was thin and brittle. These results suggest the snails were experiencing physiological stress. Laboratory experiments are now in progress to test two hypotheses: (1) physiological effects of stress in Pleurocera resulted from exposure to coal-ash contaminated sediment, and (2) selenium and arsenic, contaminants concentrated in coal-ash, contributed to these effects

305

Environmental impacts of the coal ash spill in Kingston, Tennessee: an 18-month survey.  

Science.gov (United States)

An 18 month investigation of the environmental impacts of the Tennessee Valley Authority (TVA) coal ash spill in Kingston, Tennessee combined with leaching experiments on the spilled TVA coal ash have revealed that leachable coal ash contaminants (LCACs), particularly arsenic, selenium, boron, strontium, and barium, have different effects on the quality of impacted environments. While LCACs levels in the downstream river water are relatively low and below the EPA drinking water and ecological thresholds, elevated levels were found in surface water with restricted water exchange and in pore water extracted from the river sediments downstream from the spill. The high concentration of arsenic (up to 2000 ?g/L) is associated with some degree of anoxic conditions and predominance of the reduced arsenic species (arsenite) in the pore waters. Laboratory leaching simulations show that the pH and ash/water ratio control the LCACs' abundance and geochemical composition of the impacted water. These results have important implications for the prediction of the fate and migration of LCACs in the environment, particularly for the storage of coal combustion residues (CCRs) in holding ponds and landfills, and any potential CCRs effluents leakage into lakes, rivers, and other aquatic systems. PMID:21105737

Ruhl, Laura; Vengosh, Avner; Dwyer, Gary S; Hsu-Kim, Heileen; Deonarine, Amrika

2010-12-15

306

EFFECTS OF THE DISPOSAL OF COAL WASTE AND ASHES IN OPEN PITS  

Science.gov (United States)

The objective of this study was to determine the extent of groundwater quality deterioration when coal mine solid waste (refuse) and power plant ashes were disposed of into open pits. In addition, disposal methods were developed and procedures for planning and designing disposal ...

307

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)

308

DESIGN AND CHARACTERIZATION OF AN ULTRAFINE COAL ASH AEROSOL GENERATOR FOR DIRECT ANIMAL EXPOSURE STUDIES  

Science.gov (United States)

Primary ultrafine particulate matter (PM) is produced during pulverized coal combustion by the nucleation and heterogeneous condensation of vapor-phase species. This differs from the mechanisms that control the formation of the supermicron fly ash that is heavily influenced by t...

309

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

OpenAIRE

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...

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

2012-01-01

310

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)

311

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

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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.

BORISLAV GRUBOR

2003-02-01

312

Selenium and arsenic speciation in fly ash from full-scale coal-burning utility plants.  

Science.gov (United States)

X-ray absorption fine structure spectroscopy has been used to determine directly the oxidation states and speciation of selenium and arsenic in 10 fly ash samples collected from full-scale utility plants. Such information is needed to assess the health risk posed by these elements in fly ash and to understand their behavior during combustion and in fly ash disposal options, such as sequestration in tailings ponds. Selenium is found predominantly as Se(IV) in selenite (SeO3(2-)) species, whereas arsenic is found predominantly as As(V) in arsenate (AsO4(3-)) species. Two distinct types of selenite and arsenate spectra were observed depending upon whether the fly ash was derived from eastern U.S. bituminous (Fe-rich) coals or from western subbituminous or lignite (Ca-rich) coals. Similar spectral details were observed for both arsenic and selenium in the two different types of fly ash, suggesting that the postcombustion behavior and capture of both of these elements are likely controlled by the same dominant element or phase in each type of fly ash. PMID:17539538

Huggins, Frank E; Senior, Constance L; Chu, Paul; Ladwig, Ken; Huffman, Gerald P

2007-05-01

313

Aluminum recovery from coal fly ash by high temperature chlorination  

Energy Technology Data Exchange (ETDEWEB)

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.

Wijatno, H.

1977-10-01

314

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

Directory of Open Access Journals (Sweden)

Full Text Available Electrostatic Precipitators (ESP are control devices widely used for collection of fly ash in Indian coal based thermal power plants. The design, performance, sizing, collection and operation of ESP depend largely on the properties and quality of the coal burned and the fly ash generated in the boilers. This study presents the influence of fly ash composition on the resistivity of Indian fly ash generated from coal based power plants, which is one of the critical parameter required to make accurate predictions of ESP in terms of their collection efficiency. The fly ash electrical resistivity measurements were conducted over a wide range of temperature in both ascending and descending cycles in the range of 90 to 455ºC at 9% moisture as per IEEE-Standard 548 (1991. The earlier developed Empirical relations used for calculating fly ash electrical resistivity for western coals were modified for the calculations of electrical resistivity of Indian fly ashes and new empirical relations have been developed based on experimental results and chemical composition of fly ash samples collected from different coal based power plants in India which have different chemical composition in comparison to western coals. Results in the newly developed correlations show better agreements with experimentally determined resistivity compared to those developed by Bickelhaupt and others

Syed Javid Ahmad Andrabi

2013-02-01

315

Basic study on ash removal from coal - influence of mineral distribution on characteristics of ash removal from coal  

Energy Technology Data Exchange (ETDEWEB)

The mineral distribution in coal was investigated to develop an effective removal method of mineral matter. Using gravity specific separation method, the characteristics of mineral removal from coal were evaluated. It was found that the removal of mineral matter from coal with linear shape or cloudy shape which distribute fine particles were more difficult. Using photomicrographic analysis, mineral distribution for size and shape in coal was investigated. This result showed that the distribution was obtained by discrimination method between mineral and organic matter using luminance distribution obtained from the photomicrograph, and the ratio of maximum length to projected area diameter was suitable shape factor of mineral matter. 4 refs., 5 figs., 1 tab.

Y. Hiei; H. Shirai; H. Kanda [Central Research Institute of Electric Power Industry, Yokosuka-shi (Japan). Yokosuka Research Laboratory, Chemical Energy Engineering Department

2003-07-01

316

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

DEFF Research Database (Denmark)

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.

Arvelakis, Stelios; Frandsen, Flemming

2007-01-01

317

Use of coal ash in production of concrete containing contaminated sand  

International Nuclear Information System (INIS)

There are between 2 to 3.5 million underground storage tanks located throughout the nation. Most of these tanks, which store oils and gasolines, are leaking making them one of the primary sources of soil contamination. Adding coal ash or cement to contaminated soil has been used to obtain stationary and inert wastecrete. By using this procedure, stabilization (limiting the solubility and mobility of the contaminants) and solidification (producing a solid waste block) of contaminated soils are successfully achieved. This paper investigates another re-use option of coal ash and contaminated soils. An experimental study evaluating the effectiveness of using coal ash with oil contaminated sand in concrete production is presented. A control mix made of clean sand was designed to yield 500 psi of compressive strength. Sand, artificially contaminated with 3% by weight of motor oil, was used as clean sand replacement. Six concrete mixtures were tested in compression and flexure. The six mixtures were obtained by increasing the ratio of contaminated sand to clean sand, namely; 10%, 20% and 40% and by introducing coal ash to the concrete mixture, namely; 20% of the cement weight. The test results indicate that the inclusion of oil contaminated sand in concrete reduces the compressive and flexural strengths. However, this decrease in strength is compensated by introducing coal ash in the mixture. Regaining that strength offers the possibility of using such concrete as a construcility of using such concrete as a construction material in special structural applications. More research is required to establish better understanding of that composite and suggest feasible applications

318

An attempt to evaluate some regression models used for radiometric ash determination in the brown coal  

International Nuclear Information System (INIS)

Five different regression models for determination of the ash as well as iron and calcium contents in brown coal using fluorescence and scattering of X-rays have been evaluated. Calculations were done using experimental results obtained from the natural brown coal samples to which appropriate quantities of iron, calcium and silicon oxides were added. The secondary radiation was excited by Pu-238 source and detected by X-ray argone filled proportional counter. The investigation has shown the superiority of the multiparametric models over the radiometric ash determination in the pit-coal applying aluminium filter for the correction of the influence of iron content on the intensity of scattered radiation. Standard error of estimation for the best algorithm is about three time smaler than that for algorithm simulating application of the aluminium filter. Statistical parameters of the considered algorithm were reviewed and discussed. (author)

319

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

320

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

Directory of Open Access Journals (Sweden)

Full Text Available

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 treated and untreated sample and compared with each other. Experimental results have shown that significant increases in grindability were achieved when the coal samples were exposed to microwave radiation. The ISI of samples decreased up to 96%.

Key words: Microwave energy; Low rank coal; Crushability; Grindability; Impact strength ?ndex (ISI

O. Y. Toraman

2012-06-01

321

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

International Nuclear Information System (INIS)

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

322

Determination of the kinetic models and associated parameters for the low temperature combustion and gasification of high-ash coal chars / Delani Njapha  

OpenAIRE

South Africa has large coal reserves and the power generation industry produces approximately 95% of the electricity from coal. Most of the high-grade coal is exported leaving behind a discard of high ash coal. For the power generation industry to sustain itself, some means of processing the high ash coal should be implemented. A fluidised bed gasification process is seen as the best alternative to conventional pulverised coal combustion process since it can handle a wide varie...

Njapha, Delani

2003-01-01

323

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

OpenAIRE

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 o...

Abdulhameed Umar Abubakar; Khairul Salleh Baharudin

2012-01-01

324

Regeneratively cooled coal combustor/gasifier with integral dry ash removal  

Science.gov (United States)

A coal combustor/gasifier is disclosed which produces a low or medium combustion gas for further combustion in modified oil or gas fired furnaces or boilers. Two concentric shells define a combustion volume within the inner shell and a plenum between them through which combustion air flows to provide regenerative cooling of the inner shell for dry ash operation. A fuel flow and a combustion air flow having opposed swirls are mixed and burned in a mixing-combustion portion of the combustion volume and the ash laden combustion products flow with a residual swirl into an ash separation region. The ash is cooled below the fusion temperature and is moved to the wall by centrifugal force where it is entrained in the cool wall boundary layer. The boundary layer is stabilized against ash re-entrainment as it is moved to an ash removal annulus by a flow of air from the plenum through slots in the inner shell, and by suction on an ash removal skimmer slot.

Beaufrere, Albert H. (Huntington, NY)

1983-10-04

325

Pulmonary effects of ultrafine coal fly ash inhaled by guinea pigs.  

Science.gov (United States)

Guinea pigs were exposed to ultrafine coal fly ash produced in a laboratory furnace. The average mass median aerodynamic diameter and the average mass concentration of Illinois no. 6 fly ash produced in all exposure conditions were 0.21 microns and 5.8 mg/m3, respectively. In guinea pigs exposed to Illinois no. 6 fly ash, total lung capacity (TLC), vital capacity (VC), and diffusing capacity for carbon monoxide (DLco) were significantly reduced below the control values immediately, 2 h, and 8 h postexposure. The diffusing capacity was still 10% below the control 96 h after exposure. The total sulfate in the Illinois no. 6 fly ash as determined using ion chromatography is 1105 +/- 120 micrograms/m3. Animals exposed to the Montana lignite fly ash at comparable concentration and particle size did not show alteration in diffusing capacity. The data suggest that part of the sulfate present in the fly ash of Illinois no. 6 could be in the form of sulfuric acid and is responsible for the adverse effects observed in the exposed animals. The sulfuric acid in the fly ash of Montana lignite is neutralized by its high alkali content and produces no change in lung functions. PMID:2299692

Chen, L C; Lam, H F; Kim, E J; Guty, J; Amdur, M O

1990-01-01

326

Suppression of fine ash formation in pulverized coal flames. Final technical report, September 30, 1992--January 31, 1996  

Energy Technology Data Exchange (ETDEWEB)

Coal ash, and particularly fine fly ash, remain one of the principal practical and environmental problems in coal-based power generation. In particular, submicron aerosols are identified with direct inhalation risk. Submicron ash is thought to arise from mineral vaporization during char combustion, followed by nucleation, condensation and coagulation to yield an aerosol. While aerosols are predominantly made out of volatile alkali minerals, they also can include refractory oxides that are chemically reduced to more volatile forms within the char particle and vaporized. Most of the ash of size greater than 1 {mu}m is generated by agglomeration of mineral as the char particle bums out. These two principal mechanisms are thought to account for most of the ash generated in coal combustion. Previous research has shown that various forms of coal treatment can influence the yields of fine ash from combustion. The research reported here investigates various forms of treatment, including physical coal cleaning, aerodynamic sizing, degree of grinding, and combinations of these on both aerosol yields and on yields of fine residual ash (1-4 {mu}m). The work also includes results from the combustion of artificial chars that include individual mineral elements. This research shows that these various forms of coal treatment can significantly change ash characteristics. While none of the treatments affected the bulk of the residual ash size distribution significantly, the yield of the ash aerosol mode (d<0.5 {mu}m) and fine residual ash mode (1-4 {mu}m) are changed by the treatments.

Kramlich, J.C.; Chenevert, B.; Park, Jungsung; Hoffman, D.A.; Butcher, E.K.

1996-07-19

327

Mixtures of coal ash and compost as substrates for highbush blueberry  

Energy Technology Data Exchange (ETDEWEB)

Bottom ash from a coal-fired power plant and two composts were tested as components of soil-free media and as soil amendments for growing highbush blueberry (Vaccinium corymbosum L.). Combinations of ash and compost were compared to Berryland sand, and Manor clay loam, and compost amended Manor clay loam. The pH of all treatment media was adjusted to 4.5 with sulfur at the beginning of the experiment. In 1997, plants of 'Bluecrop' and 'Sierra' were planted in 15-dm{sup 3} pots containing the pH-adjusted treatment media. The first substantial crop was harvested in 1999. At the end of the 1999 season, one half of the plants were destructively harvested for growth analysis. The remaining plants were cropped again in 2000. Yield and fruit size data were collected in both seasons, and leaf and fruit samples were collected in 1999 for elemental analysis. The presence of coal ash or composted biosolids in the media had no detrimental effect on leaf or fruit elemental content. Total growth and yield of both cultivars was reduced in clay loam soil compared to Berryland sand, whereas growth and yield of plants in coal ash-compost was similar to or exceeded that of plants in Berryland sand.

Black, B.L.; Zimmerman, R.H. [ARS, Beltsville, MD (USA). USDA Henry A Wallace Beltsville Agriculture Research Center, Fruit Lab.

2002-07-01

328

Catalytic oxidation of gaseous reduced sulfur compounds using coal fly ash  

International Nuclear Information System (INIS)

Activated carbon has been shown to oxidize reduced sulfur compounds, but in many cases it is too costly for large-scale environmental remediation applications. Alternatively, we theorized that coal fly ash, given its high metal content and the presence of carbon could act as an inexpensive catalytic oxidizer of reduced sulfur compounds for 'odor' removal. Initial results indicate that coal fly ash can catalyze the oxidization of H2S and ethanethiol, but not dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) at room temperature. In batch reactor systems, initial concentrations of 100-500 ppmv H2S or ethanethiol were reduced to 0-2 ppmv within 1-2 and 6-8 min, respectively. This was contrary to control systems without ash in which concentrations remained constant. Diethyl disulfide was formed from ethanethiol substantiating the claim that catalytic oxidation occurred. The presence of water increased the rate of adsorption/reaction of both H2S and ethanethiol for the room temperature reactions (23-25 deg. C). Additionally, in a continuous flow packed bed reactor, a gaseous stream containing an inlet H2S concentration of 400-500 ppmv was reduced to 200 ppmv at a 4.6 s residence time. The removal efficiency remained at 50% for approximately 4.6 h or 3500 reactor volumes. These results demonstrate the potential of using coal fly ash in reactors for removal of H2S and other reduced sulfur compoundsuced sulfur compounds

329

Catalytic oxidation of gaseous reduced sulfur compounds using coal fly ash.  

Science.gov (United States)

Activated carbon has been shown to oxidize reduced sulfur compounds, but in many cases it is too costly for large-scale environmental remediation applications. Alternatively, we theorized that coal fly ash, given its high metal content and the presence of carbon could act as an inexpensive catalytic oxidizer of reduced sulfur compounds for "odor" removal. Initial results indicate that coal fly ash can catalyze the oxidization of H(2)S and ethanethiol, but not dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) at room temperature. In batch reactor systems, initial concentrations of 100-500 ppmv H(2)S or ethanethiol were reduced to 0-2 ppmv within 1-2 and 6-8 min, respectively. This was contrary to control systems without ash in which concentrations remained constant. Diethyl disulfide was formed from ethanethiol substantiating the claim that catalytic oxidation occurred. The presence of water increased the rate of adsorption/reaction of both H(2)S and ethanethiol for the room temperature reactions (23-25 degrees C). Additionally, in a continuous flow packed bed reactor, a gaseous stream containing an inlet H(2)S concentration of 400-500 ppmv was reduced to 200 ppmv at a 4.6s residence time. The removal efficiency remained at 50% for approximately 4.6h or 3500 reactor volumes. These results demonstrate the potential of using coal fly ash in reactors for removal of H(2)S and other reduced sulfur compounds. PMID:12409240

Kastner, James R; Das, K C; Melear, Nathan D

2002-11-11

330

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

Science.gov (United States)

In this study, several fly ash (FA)-based composite coagulants, leached by hydrochloric acid, were prepared to treat coal washing wastewater. The concentrations of Al(3+) and Fe(2+)/Fe(3+) 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 Al(3+) and Fe(3+) and introduced Ca(2+) may have improved the coagulation process. Analysis of the dry sludge composition and slurry particle size distribution of the coal washing wastewater showed that charged colloidal particles and the fine particle distribution in the coal washing wastewater make the wastewater treatment a difficult process. Results from this study could provide a novel approach for the treatment of coal washing wastewater and coal fly ash utilization. PMID:22197558

Yan, Long; Wang, Yufei; Ma, Hongzhu; Han, Zhiping; Zhang, Qiang; Chen, Yashao

2012-02-15

331

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

332

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

Science.gov (United States)

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

Barton, T P; Ziemer, P L

1986-05-01

333

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

International Nuclear Information System (INIS)

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

334

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

International Nuclear Information System (INIS)

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

335

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

Science.gov (United States)

The use of zeolitic material synthesized from coal fly ash for the immobilization of pollutants in contaminated soils was investigated in experimental plots in the Guadiamar Valley (SW Spain). This area was affected by a pyrite slurry spill in April 1998. Although reclamation activities were completed in a few months, residual pyrite slurry mixed with soil accounted for relatively high leachable levels of trace elements such as Zn, Pb, As, Cu, Sb, Co, Tl and Cd. Phytoremediation strategies were adopted for the final recovery of the polluted soils. The immobilization of metals had previously been undertaken to avoid leaching processes and the consequent groundwater pollution. To this end, 1100 kg of high NaP1 (Na6[(AlO2)6(SiO2)10] .15H2O) zeolitic material was synthesized using fly ash from the Teruel power plant (NE Spain), in a 10 m3 reactor. This zeolitic material was manually applied using different doses (10000-25000 kg per hectare), into the 25 cm topsoil. Another plot (control) was maintained without zeolite. Sampling was carried out 1 and 2 years after the zeolite addition. The results show that the zeolitic material considerably decreases the leaching of Cd, Co, Cu, Ni, and Zn. The sorption of metals in soil clay minerals (illite) proved to be the main cause contributing to the immobilization of these pollutants. This sorption could be a consequence of the rise in pH from 3.3 to 7.6 owing to the alkalinity of the zeolitic material added (caused by traces of free lime in the fly ash, or residual NaOH from synthesis). PMID:16039695

Querol, Xavier; Alastuey, Andrés; Moreno, Natàlia; Alvarez-Ayuso, Esther; García-Sánchez, Antonio; Cama, Jordi; Ayora, Carles; Simón, Mariano

2006-01-01

336

Nitric Oxide Removal from Flue Gases by Carbon-enriched Coal Fly Ash  

OpenAIRE

The aim of this work is to evaluate the characteristics of activated and non-activated carbon obtained from carbon-enriched coal fly ashes (CECFA) from two different power stations to be used in the low temperature reduction of NO from stack gases. Carbon-rich fractions were obtained by mechanical sieving of fly ashes and by oil agglomeration. Activation of some samples was carried out in steam at 900ºC in order to develop porosity onto the samples. The obtained activated and non-activate...

Begoña Rubio; Maria Teresa Izquierdo

2013-01-01

337

Adsorption of Iron by Fly Ash Adsorbent of Coal  

Directory of Open Access Journals (Sweden)

Full Text Available Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 This research has investigated adsorption of Fe with using fly ash adsorbent. Phases of adsorption of Fe is activated with H2SO4 after that the fly ash were characterized by using XRF, FTIR and SEM. Determination of optimum conditions on the adsorption of Fe with adsorbent mass variations, variations in contact time, pH variation and variation concentration and adsorption isotherm study. Resulth show that the adsorption of Fe in optimum condition occurs in adsorbent mass of 2.5 g, for 60 minutes contact time with pH 4 at a concentration of 20 ppm. The results also able to adsorp up to 94% Fe. The adsorption of Fe with using fly ash adsorbent was more fitted to the Langmuir model than to Freundlich model

Candra Irawan

2014-04-01

338

Mercury removal from coal combustion flue gas by fly ash  

Energy Technology Data Exchange (ETDEWEB)

The effect of physicochemical properties on the mercury adsorption performance of three fly ash samples has been investigated. The samples were tested for mercury adsorption using a fixed-bed with a simulated gas. X-ray fluorescence spectroscopy, X-ray photoelectron spectroscopy and other methods were used to characterize the samples. The results indicate that mercury adsorption on fly ash is mainly physisorption and chemisorption. Uncompleted burned carbon is an important factor for the improvement of mercury removal efficiency, especially, the C-M bond may improve the oxidation of mercury, which formed via the reaction of C and Ti, Si and other elements. The higher specific surface areas and smaller pore diameter are all beneficial for the high mercury removal efficiency. The presence of O{sub 2} plays a positive role on Hg adsorption of modified fly ash, while SO{sub 2} has double role of inhibition because of competitive adsorption and promotion to chemisorption. In addition, sample modified with FeCl{sub 3} has a great performance in Hg removal.

Kuang, Junyan [Chinese Academy of Sciences, Beijing (China). Research Center for Process Pollution Control; Chinese Academy of Sciences, Beijing (China). Graduate Univ.; Xu, Wenqing; Zhu, Tingyu; Jing, Pengfei [Chinese Academy of Sciences, Beijing (China). Research Center for Process Pollution Control

2013-07-01

339

Analysis of naturally-occurring radionuclides in coal combustion fly ash, gypsum, and scrubber residue samples.  

Science.gov (United States)

Coal combustion residues from coal-fired power plants can be advantageous for use in building and construction materials. These by-products contain trace quantities of naturally occurring radionuclides from the uranium and thorium series, as well as other naturally occurring radionuclides such as K. Analysis was performed on samples of coal fly ash, flue gas desulfurization, gypsum and scrubber sludges, fixated scrubber sludges, and waste water filter cakes sampled from multiple coal-fired power plants in the United States. The radioactive content of U and Th decay series nuclides was determined using gamma photopeaks from progeny Pb at 352 keV and Tl at 583 keV, respectively; K specific activities were determined using the 1,461 keV photopeak. The samples were hermetically sealed to allow for secular equilibrium between the radium parents and the radon and subsequent progeny. Samples were analyzed in a common geometry using two high purity germanium photon detectors with low energy detection capabilities. The specific activities (Bq kg) were compared to results from literature studies including different building materials and fly ash specific activities. Fly ash from bituminous and subbituminous coals had U specific activities varying from 30-217 Bq kg (mean + 1 s.d. 119 ± 45 Bq kg) and 72-209 Bq kg (115 ± 40 Bq kg), respectively; Th specific activities from 10-120 Bq kg (73 ± 26 Bq kg) and 53-110 Bq kg (81 ± 18 Bq kg), respectively; and K specific activities from 177 to 928 Bq kg (569 ± 184 Bq kg) and 87-303 Bq kg (171 ± 69 Bq kg), respectively. Gypsum samples had U, Th, and K specific activities approximately one order of magnitude less than measured for fly ash samples. PMID:23361421

Roper, Angela R; Stabin, Michael G; Delapp, Rossane C; Kosson, David S

2013-03-01

340

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

Science.gov (United States)

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

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

2014-07-01

341

Uses of the ashes resulted from the thermopower plant based on coal, with an impact on the population exposure to the nuclear radiations  

International Nuclear Information System (INIS)

Each year large quantities of ashes from the coal combustion are produced around the world, the flying ashes as well as the slag are included in this category of ashes. For economical reasons, a large variety of coal ash applications haas been found, the most important being its utilizations in the cement and concrete fabrication. Some types of concrete include up to 80% flying ashes. The ash resulted from the coal is also used as a stabilizer in the roads fill up mixed with bitumen as a soil amendment or fertilizer in agriculture. All these utilizations of the coal ashes can lead to an increase of the people exposure due to the natural irradiation sources. The paper tries to give an answer based on laboratory analysis and adequate calculations concerning the danger of radioactive contamination in case of using the flying ashes, resulting from burning of coal in thermopower plant in the building materials industry. (author)

342

Variations of mercury content in feed coal and fly ash from a coal-fired power plant over thirty-eight weeks; parameters influencing the variation  

Energy Technology Data Exchange (ETDEWEB)

Subbituminous feed coals and its corresponding fly ashes were sampled and analyzed from a coal-fired power plant from Alberta, Canada over a period of thirty-eight weeks. The feed coals were analyzed for proximate analysis, Hg, sulphur, and ash content. The fly ashes were examined for C and Hg content. The carbon/char and carbon content of fly ashes were separated using an HCl and HF digestion. The carbon/char in the fly ash was grouped into reactive vitrinitic/bimacerate and less reactive inertinitic chars. The results indicates that the highly porous vitrinitic/bimacerate chars may be responsible for the capture of mercury, as suggested by the positive correlation between mercury and carbon content of fly ash and with vitrinitic/bimacerate chars. The emitted mercury was calculated and compared to mercury emitted from the stack during the mass balance study. The mercury content of feed coal ranged from 0.029 to 0.069 mg/kg. The present results also shows some variation in the amount of mercury captured by fly ash, ranging from 0.069 to 0.112 mg/kg, or from 24 to 51%, mercury input by feed coal. 23 refs., 7 figs.

F. Goodarzi; J. Reyes; D. Rose [Geological Survey of Canada-Calgary, Calgary, AB (Canada). Environmental Studies Group

2005-07-01

343

Characterization of coal fly ash components by laser-induced breakdown spectroscopy  

Energy Technology Data Exchange (ETDEWEB)

The high sensitivity of laser-induced breakdown spectroscopy (LIBS) for the detection of most of the fly ash components enables the analysis of these residues produced during the combustion of coal. Fly ash consists of oxides (SiO{sub 2}, Al2O{sub 3}, Fe{sub 2}O{sub 3}, CaO...) and unburnt carbon which is the major determinant of combustion efficiency in coal fired boilers. For example, an excessive amount of residual carbon dispersed in the fly ash means a significant loss of energy. Standard methods employed for the analysis of fly ash make not possible a control of boiler in real time. LIBS technique can significantly reduce the time of analysis, in some cases even an online detection can be performed. For this reason, some studies have been addressed in order to demonstrate the capability of the laser-induced breakdown spectroscopy technique for the detection of carbon content in high pressure conditions typical of thermal power plants and for the monitoring Of unburnt carbon for the boiler control in real time. In particular, the content of unburnt carbon is a valuable indicator for the control of fly ash quality and for the boiler combustion. Depending on this unburnt carbon content, fly ash can be disposed as an industrial waste or as a raw material for the production of concrete in the construction sector. In this study, analyses were performed on specimens of various forms of preparation. Pressed pellets were prepared with two different binders. Presented results concern the nature and amount of the binder used to pelletize the powder, and the laser-induced breakdown spectroscopy parameters and procedure required to draw calibration curves of elements from the fly ash. Analysis 'on tape' was performed in order to establish the experimental conditions for the future 'online analysis'.

Ctvrtnickova, T.; Mateo, M.P.; Yanez, A.; Nicolas, G. [University of La Coruna, Ferrol (Spain)

2009-10-15

344

Physical parameters affecting the emanation of Rn-222 from coal ash  

International Nuclear Information System (INIS)

The 222Rn emanation coefficients for coal ash and parameters that affected them were measured. Samples of ash from both stoker fired and pulverized coal fired boilers were obtained. 226Ra content of the samples was determined by ? spectrometric analysis of the 352 keV ? of 214Pb and the 609 keV ? of 214Bi from sealed samples of ash. Scintillation cells were constructed out of commonly available materials and a commercial preparation of ZnS(Ag) scintillator. Emanation chambers which allowed for moderately large sample masses were constructed. Emanation coefficients of the stoker fractions were measured at moisture contents of 0, 1.0, 10, 20, and 40% by weight. Within each size fraction the emanation coefficient increased as a function of moisture content, ranging from 9.58 x 10-4 to 4.13 x 10-2 between 0 and 20% moisture, respectively. Emanation coefficients also increased as a function of decreasing particle size. Emanation coefficient measurements of the pulverized ash at the moisture contents stated above ranged from 3.00 x 10-3 to 1.56 x 10-1 between 0 and 20% moisture, respectively. Both the stoker and the pulverized ashes demonstrated slight decreases in emanation coefficient between 20 and 40% moisture by weight. The effect of sample depth on observed emanation coefficient was assessed by measuring the emanation coefficient of five samples of ash each of four depths. Resulmples of ash each of four depths. Results of these measurements demonstrated no effect of depth on observed emanation coefficient

345

Geochemical and hydrogeologic evolution of alkaline discharges from abandoned coal mines  

International Nuclear Information System (INIS)

Numerous large flow (> 2,000 l/min), historically (pre-1973) acidic, abandoned underground deep mine discharges in southwestern Pennsylvania are now alkaline in character, with circumneutral pH. Recently measured flow rates are consistent with those measured 25--30 years ago; thus the change in chemistry is not simply due to dilution by increased flows of uncontaminated water through the mines. It is likely that flooding of the mines has decreased the extent of acidity enhancing aerobic conditions, and that decades of weathering have reduced the amount of reactive pyrite. However, the mines continue to yield a sulfate-rich, Fe-contaminated (19--79 ppm) drainage. These highly alkaline discharges (up to 330 ppm as CaCO3) are accompanied by large concentrations of sodium (up to 700 ppm) and suggest cation exchange with the associated overburden. To assess the hydrogeological conditions that result in the formation of alkaline Fe-contaminated mine discharges, the authors examined all the major discharges from a single synclinal basin. The northeast-trending Irwin synclinal coal basin encompasses 94 mi2 and was extensively mined by underground methods during the first half of this century. All major streams that arise within or cross the syncline are polluted by mine drainage that ranges from highly acidic Fe- and Al-contaminated discharges in the northern portion of the syncline to highly alkaline, iron and sulfate-contaminated discharges to the soutulfate-contaminated discharges to the south. The hydrology of the basin is controlled by its southern plunging structure, by outcrops or drainage tunnels on the western arms of the syncline, and by several coal barriers. A first-order hydrogeologic model was constructed to evaluate ground water flow into and through the mine complexes found in the basin. The model integrates the basin geometry with structural and mine barrier components to determine groundwater flow paths and estimate residence time. Water quality is related to the cumulative proportion of up-gradient flooded and unflooded mine workings. Small discharges from unflooded, gravity-flow portions of the mined-out portion of the Pittsburgh Coal seam are highly acidic, and large artesian flows of water affected by only a short flow through flooded anoxic mine pools are moderately acidic. Those discharges subjected to increased residence time in flooded anoxic portions of the mines are increasingly alkaline. Refinement of this model could aid in prediction and hydrogeologic manipulation of these high flow Fe-contaminated discharges that are the main pollutant in many streams throughout Northern Appalachia and other coal mining areas throughout the world

346

Natural radioactive level in coal and ash from 61 coal-fired power plants in China and its impact on the environment  

International Nuclear Information System (INIS)

The concentrations of 238U, 232Th and 40K in coal and ash from 61 coal-fired power plants in China were analyzed by means of Instrumental Neutron Activation Analysis (INAA). The average values are 38, 43, 121 Bq/kg in coal and 124, 130, Bq/kg in ash, respectively. On the base of the experiments of material equilibrium and atmospheric diffusion in Shentou coal-fired power plant, the additional exposure doses to the residents around the plant produced by the natural radionuclides released from Shentou and other coal-fired power plants were calculated. The maximum of individual effective dose equivalent is less than 0.1 mSv/a. The suggestion on feasibility of utilization of these ashes in building materials is given

347

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

Directory of Open Access Journals (Sweden)

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.

Goñi, S.

2010-06-01

348

Some controls on the ash composition of Waikato coals  

Energy Technology Data Exchange (ETDEWEB)

Major element analyses, and some mineralogical analyses, are presented for ply samples taken from major coal seams at several opencast mines in the Huntly and Rotowaro Coalfields. These analyses confirm previous work indicating the strong organic association of Ca, Mg, Na, and Fe. The abundance of these elements in individual seams appears to be influenced by the presence or absence of overlying coal seams, which may have controlled the circulation of groundwater either when the organically associated elements were fixed, or during a subsequent expulsion period. Na values in a split Taupiri seam at Maori Farm Opencast vary across major sediment partings, being highest in the lowermost coal interval. Si/Al ratios vary widely, and commonly fall below the limit of kaolinite, indicating breakdown of silicates and transport of probably both silica and alumina in solution at the time of peat accumulation. Ti and P in whole coal fluctuate substantially, and their present distribution indicates mobility in solution. P concentrations may be related to nutrient influx accompanying sedimentation in the peat. Few minerals were identified in LTA. Si, Al and K are hosted by quartz, kaolinite, and traces of illite, and Ti occurs at least partly as anatase. 13 refs., 9 figs., 2 tabs.

Newman, N.A.; Newman, J. [University of Canterbury, Christchurch (New Zealand). Dept. of Geology

1993-12-31

349

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

International Nuclear Information System (INIS)

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

350

On-line determination of the ash content in coal using industrial, natural gamma-ray equipment  

Science.gov (United States)

This work presents phases of an investigation carried out in Spain to develop industrial natural-? equipment to determine the ash content in coals. Initially the programme was on a laboratory scale and later tests were performed in a coal washing plant on a mixture of washed products. The results obtained are very satisfactory since the equipment permits the ash content to be determined with a mean error of 1.3% and a SD of 1.

Alvarez, M. C.; Dopico, M. T.

1995-12-01

351

Instrumental activation analysis of coal and fly ash with thermal and epithermal neutrons and short-lived nuclides  

Science.gov (United States)

Instrumental neutron activation analysis is applied to the determination of about 25 elements in coals and fly ash by means of nuclides with half-lives of less than 48 h ; thermal and epithermal irradiations are used. The results indicate that epithermal activation is preferable for twelve of the elements (Ga, As, Br, Sr, In, Cs, Ba, La, Sm, Ho, W and U). Data for SRM 1632 (coal) and SRM 1633 (fly ash) compare favorably with the results obtained by other investigators. ?? 1976.

Steinnes, E.; Rowe, J.J.

1976-01-01

352

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

OpenAIRE

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 metal...

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

2013-01-01

353

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)

354

Neo-mineral formation during artificial coalification of low-ash - mineral free-peat material from tropical Malaysia-potential explanation for low ash coals  

Energy Technology Data Exchange (ETDEWEB)

Abundant coal deposits have very low inorganic contents (ash yield; < 2%) and hence are almost ash-free. Inexplicable to date is that the precursor of coal, modern peat deposits, almost nowhere have such low ash yields as a result of both the inorganic mineral and biogenic phytolith contents. However, despite the common occurrence of phytoliths in modern peats, they are invariably absent in coals. It has thus been hypothesized by some investigators that modern environments are not ideal analogues for the formation of low ash coal deposits. Here we present new evidence to suggest that mineral diagenesis during coalification can transform biogenic inorganics to new minerals and that a substantial component of these new minerals could be removed in solution during expulsion of moisture with coalification resulting in low ash precursors of coal. This study presents results from artificial coalification experiments of modern tropical forest peat material with ash yields between 2-4.3 wt.%. The inorganic material of the peat consists almost exclusively of Al-Si-and Si-rich phytoliths and other bioliths; no other inorganic mineral matter is present. Compressed pellets of dried peat were deformed in a Griggs constant strain rate apparatus at a constant confining pressure of 5 kb and constant strain rate of 10{sup -} {sup 5} s {sup -} {sup 1} at variable temperatures from 350 C to 550 C. The samples, exposed to artificial coalification processes, were then analysed by SEM, EDS, and XRD for semi-quantitative chemical analyses. The deformed material showed a lack of any biogenic silica and Al-Si-phytoliths, but contained neoformed idiomorphic quartz crystals and clays. We conclude that modern peat forming environments that have low-ash peats containing biogenic silica and other biogenic Al-Si-material can represent precursors of very low-ash coal deposits. Our experiments illustrate that during coalification, it is likely all or almost all biogenic material is transformed into new minerals, mainly quartz and clay minerals, such as kaolinite. Because natural systems are not confined to the same degree as our experiments, it is likely that part or all of the inorganic fraction migrates in solutions out of the peat or coal seam with available fluids, resulting in an almost ash-free coal deposit. (author)

Wuest, Raphael [School of Earth and Environmental Sciences, James Cook University, Townsville, 4811, QLD (Australia); Bustin, R. Marc; Ross, John [Department of Earth and Ocean Sciences, University of British Columbia, 6339 Stores Road, Vancouver, B.C. (Canada)

2008-04-03

355

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)

356

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

International Nuclear Information System (INIS)

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

357

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)

358

Alkali borosilicate glass by fly ash from a coal-fired power plant.  

Science.gov (United States)

The possibility of using coal fly ash as a silica source for alkali borosilicate glass was investigated. Alkali borosilicate glasses were prepared from the coal fly ash mixed with 30 wt.% reagents composed of Na(2)O and B(2)O(3) by susceptor-induction heating. Their densities ranged from 2.24 to 2.55 g cm(-3) and decreased as the amount of B(2)O(3) addition increased. However, the Vickers microhardness showed a different tendency with the density since the glass network connectivity improved by boron anomaly, which was identified by a nuclear magnetic resonance analysis. The Vickers microhardness of the glass product, with the addition of 15 wt.% B(2)O(3) and 15 wt.% Na(2)O, was about 4030 MPa. Furthermore, the changes in microstructure were consistent with those in the chemical stability by the toxicity characteristic leaching procedure (TCLP). PMID:18951607

Park, Jong Soo; Taniguchi, Shoji; Park, Young Jun

2009-01-01

359

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)

360

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2012-07-01

361

Coal Fly Ash Impairs Airway Antimicrobial Peptides and Increases Bacterial Growth  

OpenAIRE

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 ...

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

2013-01-01

362

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

International Nuclear Information System (INIS)

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

363

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)

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.

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

364

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2008-02-15

365

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

Science.gov (United States)

Coal fly ash has been proposed to be an alternative to lime amendment and a nutrient source of container substrates for ornamental plant production. A great concern over this proposed beneficial use, however, is the potential contamination of surface and ground water by heavy metals. In this study, three fly ashes collected from Florida, Michigan, and North Carolina and a commercial dolomite were amended in a basal substrate. The formulated substrates were used to produce Syngonium podophyllum Schott 'Berry Allusion' in 15-cm diameter containers in a shaded greenhouse. Leachates from the containers were collected during the entire six months of plant production and analyzed for heavy metal concentrations. There were no detectable As, Cr, Hg, Pb, and Se in the leachates; Cd and Mo were only detected in few leachate samples. The metals constantly detected were Cu, Mn, Ni, and Zn. The total amounts of Cu, Mn, Ni, and Zn leached during the six-month production period were 95, 210, 44, and 337 microg per container, indicating that such amounts in leachates may contribute little to contamination of surface and ground water. In addition, plant growth indices and fresh and dry weights of S. podophyllum 'Berry Allusion' produced from fly ash and dolomite-amended substrates were comparable except for the plants produced from the substrate amended with fly ash collected from Michigan which had reduced growth indices and fresh and dry weights. Thus, selected fly ashes can be alternatives to commercial dolomites as amendments to container substrates for ornamental plant production. The use of fly ashes as container substrate amendments should represent a new market for the beneficial use of this coal combustion byproduct. PMID:18246510

Li, Qiansheng; Chen, Jianjun; Li, Yuncong

2008-02-01

366

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

Science.gov (United States)

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

Sun, Yong; Parikh, Vinay; Zhang, Lian

2012-03-30

367

Laser Induced Breakdown Spectroscopy machine for online ash analyses in coal  

Energy Technology Data Exchange (ETDEWEB)

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.

Gaft, M. [Research Department, LDS, 11 Granit St., Petach Tikva 49002 (Israel)], E-mail: michaelg@laserdetect.com; Dvir, E.; Modiano, H.; Schone, U. [Research Department, LDS, 11 Granit St., Petach Tikva 49002 (Israel)

2008-10-15

368

Laser Induced Breakdown Spectroscopy machine for online ash analyses in coal  

Science.gov (United States)

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 × 0.8 m × 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.

Gaft, M.; Dvir, E.; Modiano, H.; Schone, U.

2008-10-01

369

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)

370

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

Directory of Open Access Journals (Sweden)

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

Widi Astuti

2014-10-01

371

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

Energy Technology Data Exchange (ETDEWEB)

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

Soreau, S.

1996-12-31

372

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

Directory of Open Access Journals (Sweden)

Full Text Available The disposal of coal by products represents environmental and economical problems around the world. Therefore, the reuse and valorisation of this waste has become an important issue in the last decades. While high-value construction products containing fly ash were developed and its use is actually totally accepted as an addition to cement, the use of the bottom ash as supplementary cementitious material has not been allow. This paper examines the chemical and physical properties of fly ashes and bottom ashes from two different coal power plants in order to compare them and analyse the potential feasibility of bottom ash as cement replacement. The mechanical properties of cement mortars made with different percentages of both ashes were also study. The results obtained showed similar chemical composition of both kinds of ashes. The compressive strength values of mortars with 10 % and 25 % of cement replacement (at 28 days were above the limits established in European standards and there were not significant differences between fly ash and bottom ash from both origins.La eliminación de subproductos del carbón supone problemas ambientales y económicos en todo el mundo por lo que la reutilización y valorización de los mismos se ha convertido en un tema importante en las últimas décadas. Mientras que las cenizas volantes se han utilizado en aplicaciones de alto valor y se han desarrollado productos de construcción en los que se ha utilizado esta ceniza como adición al cemento, no se ha sido permitido la utilización de la ceniza de fondo como en cementos. Este artículo examina las propiedades químicas y físicas de las cenizas volantes y de fondo procedentes de dos centrales termoeléctricas con el objetivo de compararlas y analizar la potencial utilización de la ceniza de fondo como adición al cemento. Se han estudiado también las propiedades mecánicas de morteros de cemento fabricados con distintos porcentajes de ambas cenizas como sustitución del cemento. Los resultados obtenidos mostraron que las ambos tipos de cenizas tenían una composición química similar. Los valores de resistencia a compresión a 28 días de los morteros con un 10 % y 25 % de porcentaje de sustitución estaban dentro de los límites permitidos en la normativa Europea y no había diferencias significativas entre las cenizas volantes y de fondo procedentes de ambas centrales térmicas.

Menéndez, E.

2013-12-01

373

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

Science.gov (United States)

Geochemical processes in flooded underground coal mine complexes are controlled by the relationship between overburden mineralogy and the hydrogeologic system, which is influenced by mining methodology and discharge location. Numerous large flow (over 2,000 L/min), historically acidic, deep mine discharges in Appalachian bituminous coal basins are now net alkaline, with circumneutral pH and high concentrations of dissolved iron (20-80 ppm) and sodium (100-500 ppm) [1]. Understanding natural alkalinity production offers alternative approaches for neutralizing acid mine drainage (AMD) and has implications for predictive models, mining regulations, mine discharge remediation, and resource recovery. To determine the subsurface processes involved in the generation of natural alkalinity, we focused on the Irwin syncline, a 240 sq.-km bituminous coal basin in southwestern Pennsylvania. All major streams that arise within or cross the syncline are affected by polluted mine drainage. The pollution ranges from highly acidic iron- and aluminum-contaminated discharges in the northern portion of the basin to highly alkaline, iron and sulfate-contaminated discharges in the southern portion. Underground mine barrier data were used to divide the basin into six hydraulically related sub-basins; mine waters were collected from nine discharges across the basin [2]. Sub-basin hydrology was integrated with infiltration, discharge, and overburden geochemistry and mineralogy. Modeling of Irwin syncline flows using a solute modeling program (PHREEQC 2.4.2; [3]) indicates that the spatial and temporal change in mine water chemistry involves processes other than simple carbonate dissolution or dilution with uncontaminated water. Results indicate that the acidic discharges in the northeastern end of the basin are the product of surface water modified by pyrite oxidation and dissolution of aluminosilicate minerals. Sodium concentrations in those flows are likely the result of minor halite dissolution. The discharges in the southwestern sub-basins, however, exhibit a significant excess of sodium relative to chloride that correlates with increasing alkalinity. Modeling results are consistent with the development of net alkaline waters as a result of limestone dissolution enhanced by subsurface cation exchange reactions with coal overburden clay minerals such as illite, montmorillonite and kaolinite. The data suggest these processes occur in deeper sub-basins (overburden thickness greater than 100 m), dominated by groundwaters derived from neighboring mine pools with minimum infiltration of surface waters; this is corroborated by calculated infiltration rates for these sub-basins. [1]Weaver, T. J., Capo, R.C., Hedin, R. S., 1997, Geol. Soc. Am. Abstr. Prog., v. 29, A-321. [2]Winters, W.R., Capo, R.C., Wolinsky, M.W., Weaver, T.J., Hedin, R.S., 1999, Proc. 16th Ann. Int. Pittsburgh Coal Conf., sect. 6-5, p. 1-36. [3]Parkhurst, D.L. and Appelo, C.A.J., 1999, USGS Water Res. Invest. Rept. 99-4259, 326 p.

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

2001-12-01

374

Radon exhalation rate from coal ashes and building materials in Italy  

International Nuclear Information System (INIS)

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

375

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.)

376

Evaluation of the effects of coal fly ash amendments on the toxicity of a contaminated marine sediment  

Energy Technology Data Exchange (ETDEWEB)

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

Burgess, R.M.; Perron, M.M.; Friedman, C.L.; Suuberg, E.M.; Pennell, K.G.; Cantwell, M.G.; Pelletier, M.C.; Ho, K.T.; Serbst, J.R.; Ryba, S.A. [US EPA, Narragansett, RI (USA). Office for Research and Development

2009-01-15

377

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)

378

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

OpenAIRE

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...

Koekemoer, Andrei Frederik

2010-01-01

379

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

DEFF Research Database (Denmark)

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.

Zheng, Yuanjing; Jensen, Peter Arendt

2009-01-01

380

An investigation on the use of tincal ore waste, fly ash, and coal bottom ash as Portland cement replacement materials  

Energy Technology Data Exchange (ETDEWEB)

The possibility of using tincal ore waste (TW), coal bottom ash (BA), and fly ash (FA) as partial replacement in concrete was examined through a number of tests. The properties examined include setting time, compressive strength, mortar expansion, water consistency of mortar, and microstructure. The results showed that compressive strength of all specimens containing 1 wt.% of TW was higher than that of the control at the 28th day of curing. At 90 days, the contribution to strength by BA + TW and FA + TW was higher than in the concrete-prepared equivalent TW beyond 3 wt.% of Portland cement (PC) replacement. With the replacement of 3-5 wt.% of PC by TW, the compressive strength of the concrete decreased compared to control concrete. However, the values obtained are within the limit of Turkish Standards. Adding BA or FA with TW improved the performance relative to TW replacement only. Increasing replacement of TW gives rise to a higher setting time. As a result. TW, BA, and FA samples may be used as cementitious materials.

Kula, I.; Olgun, A.; Sevinc, V.; Erdogan, Y. [Dumlupinar University, Kutahya (Turkey). Dept. of Chemistry

2002-02-01

381

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

Science.gov (United States)

This paper assess the mechanical an environmental behaviour of cement mortars manufactured with addition of fly ash (FA) and bottom ash (BA), as partial cement replacement (10%, 25% and 35%). The environmental behaviour was studied by leaching tests, which were performed under several temperature (23 °C and 60 °C) and pH (5 and 10) conditions, and ages (1, 2, 4 and 7 days). Then, the accumulated amount of the different constituents leached was analysed. In order to obtain an environmental burden (EB) value of each cement mixture, a new methodology was developed. The EB value obtained is related to the amount leached and the hazardous level of each constituent. Finally, the integral study of compressive strength and EB values of cement mixtures allowed their classification. The results showed that mortars manufactured with ordinary Portland cement (OPC) and with coal BA had similar or even better environmental and mechanical behaviour than mortars with FA. Therefore, the partial replacement of cement by BA might be as suitable or even better as the replacement by FA. PMID:24412590

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

2014-01-15

382

Radon exhalation of cementitious materials made with coal fly ash: Part 2--testing hardened cement-fly ash pastes.  

Science.gov (United States)

Increased interest in measuring radionuclides and radon concentrations in fly ash (FA), cement and other components of building products is due to the concern about health hazards of naturally occurring radioactive materials (NORM). The paper focuses on studying the influence of FA on radon exhalation rate (radon flux) from cementitious materials. In the previous part of the paper the state of the art was presented, and the experiments for testing raw materials, Portland cement and coal fly ash, were described. Since the cement and FA have the most critical role in the radon release process relative to other concrete constituents (sand and gravel), and their contribution is dominant in the overall radium content of concrete, tests were carried out on cement paste specimens with different FA contents, 0-60% by weight of the binder (cement+FA). It is found that the dosage of FA in cement paste has a limited influence on radon exhalation rate, if the hardened material is relatively dense. The radon flux of cement-FA pastes is lower than that of pure cement paste: it is about approximately 3 mBq m(-2) s(-1) for cement-FA pastes with FA content as high as 960 kg m(-3). PMID:15885379

Kovler, K; Perevalov, A; Levit, A; Steiner, V; Metzger, L A

2005-01-01

383

Radon exhalation of cementitious materials made with coal fly ash: Part 2 - testing hardened cement-fly ash pastes  

International Nuclear Information System (INIS)

Increased interest in measuring radionuclides and radon concentrations in fly ash (FA), cement and other components of building products is due to the concern about health hazards of naturally occurring radioactive materials (NORM). The paper focuses on studying the influence of FA on radon exhalation rate (radon flux) from cementitious materials. In the previous part of the paper the state of the art was presented, and the experiments for testing raw materials, Portland cement and coal fly ash, were described. Since the cement and FA have the most critical role in the radon release process relative to other concrete constituents (sand and gravel), and their contribution is dominant in the overall radium content of concrete, tests were carried out on cement paste specimens with different FA contents, 0-60% by weight of the binder (cement+FA). It is found that the dosage of FA in cement paste has a limited influence on radon exhalation rate, if the hardened material is relatively dense. The radon flux of cement-FA pastes is lower than that of pure cement paste: it is about ?3 mBq m-2 s-1 for cement-FA pastes with FA content as high as 960 kg m-3

384

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

International Nuclear Information System (INIS)

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

385

Effects of process parameters and ash on the adsorption properties of activated carbon from coals  

International Nuclear Information System (INIS)

super-activated carbon was prepared from three representative shanxi coals, i.e. datong bituminous coal, yangquan anthracite and jincheng anthracite by KOH activation. The optimum parameters were obtained by comparing CCl/sub 4/ absorption values of activated carbon (ac). In addition, pristine coal and ac were deashed by acid washing, respectively. The effect of ash content on the adsorption properties of ac was studied. the results indicate that CCl/sub 4/ adsorption value of ac from yangquan anthracite with deashing treatment reaches up to 3301 mg/g when the activated temperature, activated time and ratio of alkali to carbon are 1830 degree C, 60 min and 5/1, respectively. (author)

386

Radiotracer evaluation of laterite and coal-ash dust discharged into the environment  

Energy Technology Data Exchange (ETDEWEB)

In Elbasan steel plant a large quantity of dust is discharged into the environment by laterite fluidized bed calciner and the coal boiler for steam production. By means of radiotracers the erosion of the laterite in the fluidized bed calciner was estimated experimentally. Based on the experimental data a mathematical model has been constructed for the erosion, which permits calculation of the mass of the dust deriving from erosion when the granulometric composition of the mineral on entry to the calciner is known. The efficiency of two types of cyclones in laterite calciner and coal boiler, for three granulometric classes of laterite dust and coal-ash was studied. Ways of reducing the quantity of dust discharged into environment are proposed.

Thereska, J.; Cuci, T.; Spahiu, P.; Plasari, E. [Institute of Nuclear Physics, Tirane (Albania). Tracer Section

1993-12-31

387

Chronic exposure to coal fly ash causes minimal changes in corticosterone and testosterone concentrations in male southern toads Bufo terrestris.  

Science.gov (United States)

More than 50% of the electricity in the United States is produced by coal-burning power plants. The byproduct of coal-burning plants is coal fly ash, which contains increased concentrations of trace metals and is disposed of in collection basins. Southern toads (Bufo terrestris) frequently use these basins for reproduction. Male toads were collected in spring 2001 and 2002 from an ash basin and a reference site and divided into four groups: toads collected at the control site and maintained on (1) control substrate and food or (2) ash and contaminated food and toads collected at the ash site and maintained in (3) control or (4) ash conditions. Blood was collected periodically during 5 months to determine testosterone and corticosterone concentrations. Reference to ash toads exhibited a significant, transient increase in corticosterone at 4 weeks, but neither corticosterone nor testosterone continued to increase beyond this time. In contrast, toads caught and maintained on ash did not exhibit increased corticosterone. Testosterone in these toads appeared to be unrelated to ash exposure. This unexpected lack of a corticosterone response and no effect on testosterone suggests that toads chronically exposed to trace metals can acclimate to a polluted environment, but they may still experience subtle long-term consequences. PMID:16783624

Ward, C K; Mendonça, M T

2006-08-01

388

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

DEFF Research Database (Denmark)

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.

Wu, Hao; Shafique Bashir, Muhammad

2013-01-01

389

Bioassessment of Alkaline Drainage from Coal Mines in Western Pennsylvania: A Ten-Year Study  

Science.gov (United States)

Abandoned coal mine drainage (AMD) impacts over 6,500 km of streams in Pennsylvania. AMD alters stream pH and dissolved ions, and often produces precipitated metals that coat stream substrates. We studied 3 streams from 1994 to 2004, before and after treatment wetlands were constructed in 1997-9 to intercept discharges with high iron (60-90 ppm) and alkalinity (100-130 mg/L CaCO3) and low manganese and aluminum. Receiving streams are circumneutral with 5-40 ppm total iron and thick iron precipitate. Annual replicate sets of Surber and D nets, rock wash, and leaf packs were sampled. Regression analysis of genus level data showed statistically significant improvement in the two second-order streams. Community profiles are now statistically similar in sites upstream and downstream from AMD. The larger third stream showed moderate AMD impacts before 1997 and no statistically significant biological trends after wetlands substantially decreased levels of AMD in all three streams. This study indicated biological recovery lagged behind chemical recovery by at least 3 years. The patterns of appearance of macroinvertebrate taxa in alkaline AMD sites indicate that commonly used tolerance indices developed for organic pollution do not predict macroinvertebrate responses to AMD. Our study can provide a basis for broader benchmarks in bioassessment of coal mine pollution.

Walter, C. A.; Nelson, D.; Earle, J. I.

2005-05-01

390

Extraction of alumina from coal fly ash generated from a selected low rank bituminous South African coal  

Energy Technology Data Exchange (ETDEWEB)

Coal fly ash typically contains 30% alumina, 1.5% titania, 2.5% hematite, 9.5% lime and 60% silica. Due to the availability of alumina in fly ash and large quantities of alumina imported by South Africa annually, a project was initiated to evaluate the possibility of extracting the alumina from fly ash. The mullite-containing fly ash was mixed with calcium oxide and subsequently, calcined at a temperature ranging from 1000 to 1200{sup o}C to yield acid or base soluble calcium aluminate. The calcined ash was leached with a sulphuric acid solution to produce a solution containing iron, aluminium and titanium species. An aluminium extraction efficiency of 85% was achieved when the sintered pellets were leached with sulphuric acid using an acid concentration of 6.12 mol dm{sup -3} at 80{sup o}C for 4 h. The leached residue, from the sulphuric acid leaching, could be considered as a co-product in this process and could possibly be suitable for use as a lightweight aggregate in masonry concrete applications or cement production. Purification methods such as precipitation, solvent extraction and crystallization were evaluated to selectively separate both iron and titanium ions from the aluminium containing aqueous solution. The solvent extraction method was found to be superior for the removal of iron and titanium from the aluminium-containing aqueous solution. The major final product obtained with the solvent extraction method contained approximately 99.4% alumina, whilst the minor product contained 97% titanium oxide. The alumina product can be used for the production of aluminium chemicals and in refractories, while the titanium oxide product can possibly be used as a white pigment in the production of paints.

Matjie, R.H.; Bunt, J.R.; van Heerden, J.H.P. [Sasol Technology Pty Ltd, Sasolburg (South Africa)

2005-03-01

391

Catalytic oxidation of gaseous reduced sulfur compounds using coal fly ash  

Energy Technology Data Exchange (ETDEWEB)

Activated carbon has been shown to oxidize reduced sulfur compounds, but in many cases it is too costly for large-scale environmental remediation applications. Alternatively, we theorized that coal fly ash, given its high metal content and the presence of carbon could act as an inexpensive catalytic oxidizer of reduced sulfur compounds for 'odor' removal. Initial results indicate that coal fly ash can catalyze the oxidization of H{sub 2}S and ethanethiol, but not dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) at room temperature. In batch reactor systems, initial concentrations of 100-500 ppmv H{sub 2}S or ethanethiol were reduced to 0-2 ppmv within 1-2 and 6-8 min, respectively. This was contrary to control systems without ash in which concentrations remained constant. Diethyl disulfide was formed from ethanethiol substantiating the claim that catalytic oxidation occurred. The presence of water increased the rate of adsorption/reaction of both H{sub 2}S and ethanethiol for the room temperature reactions (23-25 deg. C). Additionally, in a continuous flow packed bed reactor, a gaseous stream containing an inlet H{sub 2}S concentration of 400-500 ppmv was reduced to 200 ppmv at a 4.6 s residence time. The removal efficiency remained at 50% for approximately 4.6 h or 3500 reactor volumes. These results demonstrate the potential of using coal fly ash in reactors for removal of H{sub 2}S and other reduced sulfur compounds.

Kastner, James R.; Das, K.C.; Melear, Nathan D

2002-11-11