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- Fly ash (4)
- Combustion; conversion; mineral matter; quantitative analysis; X-ray diffraction; X-ray fluorescence (2)
- 23-factorial design; manufactured coal ash aggregates; restoration; water quality (1)
- Absorption index (1)
- Alite; calcium sulfoaluminate; ferrite; hybrid cements; industrial by-products (1)
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- Ash deposition; fouling; condensation; eutectoid; sticking coefficient; erosion coefficient (1)
- Ash strategy; fly ash; coarse ash; South Africa; legislation; commercialisation (1)
- Backfill; CLSM; compressive strength; mix design; flowable fill; fly ash (1)
- Bauxite (1)
- Bearing resistance (1)
- CCR units; groundwater; remedial alternatives (1)
- CSA cement; ordinary Portland cement; ponded ash; fresh ash; hybrid clinkers (1)
- CSAB cement; low-energy cement; CFB by-products; ettringite (1)
- Catechol (1)
- Cetyl trimethyl ammonium bromide (1)
- Chemical classification (1)
- Clean Air Act; sulfur dioxide emissions; mercury; arsenic (1)
- Coal ash; alite; calcium sulfoaluminate; X-Ray diffraction; Rietveld analyses; hybrid cement (1)
- Coal ash; coal combustion product; direct shear; shear strength; triaxial; vane shear (1)
- Coal by-products; FGD-gypsum; fly ash; wheat; nitrogen; fertilizer (1)
- Coal combustion by-products; brines; desulphurisation; FGD; hydration (1)
- Coal combustion by-products; coal ash; geopolymer concrete; cementless concrete; CO2 emissions (1)
- Coal combustion products (CCPs); coal ash; flue gas desulfurization (FGD); mercury; beneficial use; wallboard (1)
- Coal combustion products; fly ash; intelligent compaction; cost; quality assurance (1)
- Coal fly ash (1)
- Coal fly ash; Geopolymerization; Heavy metals; Leachability; Stabilization/solidification; Carbonation (1)
- Coal fly ash; bioassay; Vibrio fischeri; bioluminescence intensity; thermoelectric power plant (1)
- Coal fly ash; heavy metals; environmental impact; degree of contamination; pollution load index; bioaccumulation factor (1)
- Coal fly ash; mineral phases; sequential extraction procedure; chemical index of weathering; chemical index of alteration; pore water pH (1)
- Coal fly ash; poultry litter; bioenergy feedstock; eastern gamagrass; soil acidity; root system architecture (1)
Articles 31 - 60 of 85
Full-Text Articles in Bioresource and Agricultural Engineering
Coal Ash By-Product From Shanxi Province, China, For The Production Of Portland–Calcium Sulfoaluminate, Tristana Y. Duvallet, Thomas L. Robl, Kevin R. Henke, Yongmin Zhou, David Harris
Coal Ash By-Product From Shanxi Province, China, For The Production Of Portland–Calcium Sulfoaluminate, Tristana Y. Duvallet, Thomas L. Robl, Kevin R. Henke, Yongmin Zhou, David Harris
Coal Combustion and Gasification Products Journal Archive
Twenty bulk samples were collected from ponded coal combustion ash in Shanxi Province, China, as part of an investigation of their beneficiation potential. The samples were shipped to the University of Kentucky, where they were chemically analyzed. The samples were highly consistent in chemistry, falling within the ASTM C-618 class F compositional range. The particle size of the ponded ash was relatively coarse, with only ,7% by weight on average, falling below 200 mesh (75 mm) particle size. The bulk of the material (.80%) was within 50 by 200 mesh (equivalent to 300 by 75 mm). X-ray diffraction investigation combined …
Effect Of Coal Fly Ash Leachate On The Bioluminescence Intensity Of Vibrio Fischeri, Shiro Ikeda, Irena Kostova, Hideaki Sekine, Yoshika Sekine
Effect Of Coal Fly Ash Leachate On The Bioluminescence Intensity Of Vibrio Fischeri, Shiro Ikeda, Irena Kostova, Hideaki Sekine, Yoshika Sekine
Coal Combustion and Gasification Products Journal Archive
Coal fly ash is a residue of coal-fired thermoelectric power plants (TPPs) and is mostly dumped in ash ponds or landfill sites, even though it potentially contains significant amounts of water-soluble hazardous contaminants. Bioassay using the bioluminescent bacterium *Vibrio fischeri* is known to be applicable for assessing the short-term and sublethal toxicity of complex mixtures without the need for precise chemical characterization. However, this type of bioassay is potentially adversely influenced by the pH-induced protein denaturation of cells. Because coal fly ash leachates often have alkaline or acidic properties, when applying the *V. fischeri*-based bioassay to the samples, we need …
Influence Of Coal-Fired Power Plant Emissions Regulations And Consequent Engineering Controls And Coal-Supply Modifications On Fly Ash Chemistry And Petrology: Examples From Kentucky Power Plants, Madison M. Hood, John G. Groppo, Michelle N. Johnston, James C. Hower, Herek L. Clack, Diego S. De Medeiros, Silvio R. Taffarel, Cesar M.N.L. Cutruneo, Luis F.O. Silva
Influence Of Coal-Fired Power Plant Emissions Regulations And Consequent Engineering Controls And Coal-Supply Modifications On Fly Ash Chemistry And Petrology: Examples From Kentucky Power Plants, Madison M. Hood, John G. Groppo, Michelle N. Johnston, James C. Hower, Herek L. Clack, Diego S. De Medeiros, Silvio R. Taffarel, Cesar M.N.L. Cutruneo, Luis F.O. Silva
Coal Combustion and Gasification Products Journal Archive
The chemistry and petrology of fly ash are controlled by a number of factors: (1) chemistry of the feed coal (and added fuels, such as petroleum coke, tires, biomass, etc.), (2) particle size of the fuel feed (controlled by pulverized fuel vs. cyclone combustion, maintenance of pulverizers, etc.), (3) design of the boiler and pollution-control system, and (4) temperature of the flue gas at the collection point. In general, for any electrostatic precipitator or baghouse system, the concentrations of volatile trace elements in fly ash will increase with a drop in the flue gas temperature and a decrease in the …
Multistage Concentration Of Cenospheres In Fly Ash Using The Inverted Reflux Classifier, A. Kiani, J. Zhou, K.P. Galvin
Multistage Concentration Of Cenospheres In Fly Ash Using The Inverted Reflux Classifier, A. Kiani, J. Zhou, K.P. Galvin
Coal Combustion and Gasification Products Journal Archive
Cenospheres are one of the most valuable components found in the fly ash waste of coal-fired power stations, consisting of hollow, aluminosilicate spherical shells and offering very low bulk density, high strength, and high thermal resistance. Although wet processing methods offer the best prospect for achieving recovery and concentration of the cenospheres, significant impediments remain for achieving satisfactory economics. This work was concerned with the recovery and concentration of cenospheres from fly ash using a novel system, the inverted reflux classifier (IRC), covering single and multistage processing. The system consists of a series of parallel inclined channels mounted underneath an …
Strengthening Black Cotton Soil With Fly Ash And Moorum: An Investigation Of The Role Of Subgrade And Subbase Layers, Gourav Saxena, Nikhlesh Chaurasia
Strengthening Black Cotton Soil With Fly Ash And Moorum: An Investigation Of The Role Of Subgrade And Subbase Layers, Gourav Saxena, Nikhlesh Chaurasia
Coal Combustion and Gasification Products Journal Archive
One of the most effective and economical methods to strengthen clayey soils is addition of stabilizing agents such as fly ash to the soil. In this study, highly plastic clay was stabilized using fly ash. Geotechnical properties such as Atterberg limits, unconfined compressive strength (UCS), and the California bearing ratio (CBR) value of virgin black cotton soil and soil treated with fly ash were evaluated. Soil was stabilized with various proportions of fly ash, i.e., at 0%, 10%, 15%, 20%, and 30%. The UCS of black cotton soil–fly ash mixes is found to be at its maximum at 20% fly …
Using Coal Fly Ash In Agriculture: Combination Of Fly Ash And Poultry Litter As Soil Amendments For Bioenergy Feedstock Production, E. Kudjo Dzantor, Ekundayo Adeleke, Vanaha Kankarla, Oluwatosin Ogunmayowa, Dafeng Hui
Using Coal Fly Ash In Agriculture: Combination Of Fly Ash And Poultry Litter As Soil Amendments For Bioenergy Feedstock Production, E. Kudjo Dzantor, Ekundayo Adeleke, Vanaha Kankarla, Oluwatosin Ogunmayowa, Dafeng Hui
Coal Combustion and Gasification Products Journal Archive
Increasing fiscal, human, and environmental costs of coal fly ash (FA) management are leading to advocacy for greater beneficial uses of the by-products as soil amendments in agriculture. Greenhouse experiments were conducted in Armour silt loam (ASL) soil that was amended with FA (10%, wt/wt) with and without poultry litter (PL 5 75 mg N/kg). Biomass productivity of eastern gamagrass (GG), a warm-season perennial grass, was measured to serve as complementary biofuel feedstock to switchgrass (SG). FA was obtained from a site at the 2008 ash spill in Kingston, TN. GG and SG were grown individually in 15-cm-wide 3 41-cm-high …
Fabrication And Testing Of Low-Energy Calcium Sulfoaluminate-Belite Cements That Utilize Circulating Fluidized Bed Combustion By-Products, Robert Jewell, Robert Rathbone, Tristana Duvallet, Thomas Robl, Kamyar Mahboub
Fabrication And Testing Of Low-Energy Calcium Sulfoaluminate-Belite Cements That Utilize Circulating Fluidized Bed Combustion By-Products, Robert Jewell, Robert Rathbone, Tristana Duvallet, Thomas Robl, Kamyar Mahboub
Coal Combustion and Gasification Products Journal Archive
The utilization of circulating fluidized bed combustion (CFBC) ash to make cement products that provide added value and offset CO2 production is the objective of this research. CFBC burns coal in the presence of a bed of slaked limestone, which effectively absorbs sulfur dioxide (SO2) to form anhydrite (CaSO4). CFBC produces two kinds of spent bed materials, coarse bottom ash and a much finer fly ash. Both of these products are very high in calcium. When properly conditioned, these materials are capable of acting as hydraulic cements, forming both calcium aluminosulfate minerals, most importantly ettringite, as well as calcium-alumina-silica gels, …
Prediction Of The Unburned Carbon Content Of Fly Ash In Coal-Fired Power Plants, Saeid R. Dindarloo, James C. Hower
Prediction Of The Unburned Carbon Content Of Fly Ash In Coal-Fired Power Plants, Saeid R. Dindarloo, James C. Hower
Coal Combustion and Gasification Products Journal Archive
Prediction of carbon content in fly ash is a valuable index in both designing and optimizing coal-fired boilers. In this study, methods of multiple regression (MR), decision trees (DT), and support vector regression (SVR) were used for prediction of unburned carbon content of fly ash in a 300-MW power plant with a tangentially fired furnace using a low-NOx concentric firing system. Twenty-one boiler operational and coal petrological variables from 21 experiments in a previous benchmark study were used. A variables correlation matrix was used for feature (independent variables) selection in order to reduce the dimensions (number) of input variables from …
Recycling Of Lignite Coal Fly Ash By Its Conversion Into Zeolites, Silviya Boycheva, Denitza Zgureva, Annie Shoumkova
Recycling Of Lignite Coal Fly Ash By Its Conversion Into Zeolites, Silviya Boycheva, Denitza Zgureva, Annie Shoumkova
Coal Combustion and Gasification Products Journal Archive
The present study emphasized the conversion of fly ash from lignite coals into zeolites by a double-stage fusion-hydrothermal synthesis. The raw and the converted fly ashes were characterized with respect to their morphology, composition, and crystallinity. The effects of process parameters such as fusion temperature, concentration of the alkaline activator, and the duration of the hydrothermal incubation on the zeolitization process were studied. The experimental results indicate that the fusion temperature does not influence the process mechanism in the range 550–850uC, but it has an acceleration effect. The elevation of the sodium hydroxide/fly ash ratio from 1.6 to 2.0 enhances …
Synthesis And Characterization Of High-Iron Alite-Calcium Sulfoaluminate-Ferrite Cements Produced From Industrial By-Products, Tristana Y. Duvallet, Youngmin Zhou, Thomas L. Robl, Rodney Andrews
Synthesis And Characterization Of High-Iron Alite-Calcium Sulfoaluminate-Ferrite Cements Produced From Industrial By-Products, Tristana Y. Duvallet, Youngmin Zhou, Thomas L. Robl, Rodney Andrews
Coal Combustion and Gasification Products Journal Archive
Ordinary Portland cement (OPC) and calcium sulfoaluminate cement (CSAC) are well-known and commonly used construction materials. The clinker phases mainly responsible for their strength development are C3S (alite) in OPC, which hydrates to form a calcium silicate gel phase; and C4A3S ´ (calcium sulfoaluminate) in CSAC, which hydrates to rapidly form ettringite. The purpose of this work was to produce high-iron alite-calcium sulfoaluminate-ferrite cements, by combining C4AF (ferrite), from 5% to 50% by weight, to the C3S and C4A3S ´ clinker phases. Producing this alite-calcium sulfoaluminate-ferrite cement would decrease the requirement of bauxite in the raw materials, which would consequently …
Experimental And Modelling Evaluation Of Slagging Behaviour Of German Lignite, Martin Kaiser, Alexander Ilyushechkin
Experimental And Modelling Evaluation Of Slagging Behaviour Of German Lignite, Martin Kaiser, Alexander Ilyushechkin
Coal Combustion and Gasification Products Journal Archive
The behaviour of mineral matter is important for the characterisation of coal for use in entrained-flow gasification technologies. We investigated four behavioural characteristics—ash fusion temperatures (AFT), slag viscosity versus temperature profiles, temperatures of critical viscosity (TCV), and slag phase compositions—of Rhenish lignite coal ash using laboratory and modelling tools. Our modelling of AFT using coal ash composition provided a wide range of data, with only one (modified) model demonstrating agreement with experimental data. Experimental slag viscosity data were obtained over a temperature range from 1200uC to 1500uC. Where relevant, TCV was also measured. Comparison of these data to the calculated …
Fly Ash As A Potential Scrubber Of Acidic Wastes From The Phosphate Industries In Israel, Roy Nir Lieberman, Eli Lederman, Ithamar Pelly, Haim Cohen
Fly Ash As A Potential Scrubber Of Acidic Wastes From The Phosphate Industries In Israel, Roy Nir Lieberman, Eli Lederman, Ithamar Pelly, Haim Cohen
Coal Combustion and Gasification Products Journal Archive
Fly ash (FA) is produced in Israeli utilities via bituminous coal combustion. It is used as a cement additive or in concrete production, and its economic value is low. The FA produced in Israel is very basic (defined as class F) owing to ambient air quality standards that impose low sulfur content in the imported coals. Because the lime content is high (in the South African coal, ,10 wt%), it is a good potential chemical scrubber to acidic wastes. The phosphate industry in Israel produces mainly phosphate fertilizers and water-treatment products as well as phosphoric acid. The production methods rely …
Geochemistry And Mineralogy Of Coal-Fired Circulating Fluidized Bed Combustion Fly Ashes, Luis F.O. Silva, Marcos L.S. Oliveira, Rubens M. Kautzmann, Claudete G. Ramos, Maria Izquierdo, Shifeng Dai, Jennifer Wilcox, Jeremy Hoffman, James C. Hower
Geochemistry And Mineralogy Of Coal-Fired Circulating Fluidized Bed Combustion Fly Ashes, Luis F.O. Silva, Marcos L.S. Oliveira, Rubens M. Kautzmann, Claudete G. Ramos, Maria Izquierdo, Shifeng Dai, Jennifer Wilcox, Jeremy Hoffman, James C. Hower
Coal Combustion and Gasification Products Journal Archive
The fuel, bed ash, and fly ash were sampled from a circulating fluidized bed combustion (CFBC) unit at two times. The first sampling was a high-sulfur (S) coal-only run, and the second sampling coincided with an experimental burn of up to 10% switchgrass (Panicum virgatum) pressed pellets mixed with a high-S coal. The latter blend had a higher moisture content and a lower heating value than the coal-only fuel. Given the time between the samplings and the special needs for the experimental run, unavoidable changes in the coal and limestone complicate comparisons of the bed ash and fly ash chemistry …
Trends In Coal Utilization And Coal Combustion Product Production In Kentucky: Results Of The 2012 Survey Of Power Plants, James C. Hower, Gerald A. Thomas, Shelley G. Hopps
Trends In Coal Utilization And Coal Combustion Product Production In Kentucky: Results Of The 2012 Survey Of Power Plants, James C. Hower, Gerald A. Thomas, Shelley G. Hopps
Coal Combustion and Gasification Products Journal Archive
The University of Kentucky Center for Applied Energy Research has conducted a survey of Kentucky’s utility coal-fired power plants every 5 years since 1992. The survey includes a collection of the feed coal and the coal combustion products (CCPs). The latest collection was in 2012, with the accompanying information survey covering trends in 2011. Overall coal-fired energy production decreased, and the nature of the CCPs changed for a number of reasons, including but not limited to, increased gas production in the Appalachians, a series of warm winters, energy conservation, depletion of Appalachian coal reserves, and utility responses to regulations. From …
The John Zink Hamworthy Combustion Handbook, 2nd Edition, Volume 1: Fundamentals, Edited By Charles E. Baukal, Jr., Crc Press, Boca Raton, Fl, 2013., Payal A. Chandan
The John Zink Hamworthy Combustion Handbook, 2nd Edition, Volume 1: Fundamentals, Edited By Charles E. Baukal, Jr., Crc Press, Boca Raton, Fl, 2013., Payal A. Chandan
Coal Combustion and Gasification Products Journal Archive
No abstract provided.
Location Of Cerium In Coal-Combustion Fly Ashes: Implications For Recovery Of Lanthanides, James C. Hower, John G. Groppo, Prakash Joshi, Shifeng Dai, David P. Moecher, Michelle N. Johnston
Location Of Cerium In Coal-Combustion Fly Ashes: Implications For Recovery Of Lanthanides, James C. Hower, John G. Groppo, Prakash Joshi, Shifeng Dai, David P. Moecher, Michelle N. Johnston
Coal Combustion and Gasification Products Journal Archive
Given the worldwide demand for rare earth elements (REEs) in modern electronics, all potential sources of the REEs should be investigated. Coal-combustion fly ash represents a potential source of REEs. Fly ashes, derived from the combustion of coals from Kentucky in the United States and Jungar in China, were examined by wavelength-dispersive spectrometry electron microprobe analysis of epoxy-bound polished pellets. From previous studies, it was known that the REEs did not show any enrichment relative to flue gas temperature at the point of collection or to the particle size, that is, external surface area, of the particles. Cerium, the most …
Chemical Partitioning And Mobility Of Trace Elements In Dry Disposed Weathered Ash Conditioned With High-Saline Effluents, S.A. Akinyemi, A. Akinlua, W.M. Gitari, R.O. Akinyeye, L.F. Petrik
Chemical Partitioning And Mobility Of Trace Elements In Dry Disposed Weathered Ash Conditioned With High-Saline Effluents, S.A. Akinyemi, A. Akinlua, W.M. Gitari, R.O. Akinyeye, L.F. Petrik
Coal Combustion and Gasification Products Journal Archive
Weinvestigated the mobility of inorganic elements in the ash dump due to chemical interaction of weathered dry disposed ash conditioned with high-saline effluents and ingressed CO2 from atmosphere and percolating rainwater. Drilled ash core samples collected from dry disposed ash dump at a South African coal-burning power station were characterized using X-ray diffraction (XRD) and X-ray fluorescence (XRF) analyses. A modified sequential extraction procedure was selected to determine the mineralogical association of the investigated elements in the 1-year-old drilled ash cores. Major mineral phases are quartz and mullite and other minor phases included hematite, lime, calcite, anorthite, mica, and enstatite. …
Effects Of Coal Combustion By-Product–Encapsulated Ammonium Nitrate On Wheat Yield And Uptake Of Nitrogen And Metals, Eton E. Codling
Effects Of Coal Combustion By-Product–Encapsulated Ammonium Nitrate On Wheat Yield And Uptake Of Nitrogen And Metals, Eton E. Codling
Coal Combustion and Gasification Products Journal Archive
Ammonium nitrate (AN) is an essential plant nutrient for plant growth. Ammonium nitrate is also an ingredient in explosives. Research is being conducted on reducing the explosiveness of AN by encapsulating it with the use of coal by-products. The objective of this greenhouse pot study was to determine the effects of class C and F fly ash and flue gas desulfurization-gypsum-encapsulated AN on biomass, grain, and straw yield and nitrogen and metals uptake by wheat. Encapsulated AN was mixed with a low-nitrogen soil at 56 and 112 kg N ha^-1^, as well as unencapsulated AN as a control, and planted …
Geotechnical Characterization Of Clinker-Stabilized Fly Ash–Coal Mine Overburden Mixes For Subbase Of Mine Haul Road, Soumya Ranjan Mallick, Manoj Kumar Mishra
Geotechnical Characterization Of Clinker-Stabilized Fly Ash–Coal Mine Overburden Mixes For Subbase Of Mine Haul Road, Soumya Ranjan Mallick, Manoj Kumar Mishra
Coal Combustion and Gasification Products Journal Archive
Fly ash is a major by-product of thermal power plants that adversely affects land, water, and air. Its gainful utilization in many areas is being continuously explored. Use of fly ash in opencast coal mine haul road construction is one such option. This article reports detailed laboratory investigations carried out on clinker-stabilized fly ash–mine overburden mixes to evaluate their suitability for subbase of mine haul roads. Composite materials were prepared from fly ash, mine overburden, and clinker at different proportions. Proctor compaction test, unconfined compressive strength (UCS), and ultrasonic pulse velocity tests were carried out at different curing periods. UCS …
A Note On The Occurrence Of Yttrium And Rare Earth Elements In Coal Combustion Products, James C. Hower, Shifeng Dai, Vladimir V. Seredin, Lei Zhao, Irena J. Kostova, Luis F.O. Silva, Sarah M. Mardon, Gulbin Gurdal
A Note On The Occurrence Of Yttrium And Rare Earth Elements In Coal Combustion Products, James C. Hower, Shifeng Dai, Vladimir V. Seredin, Lei Zhao, Irena J. Kostova, Luis F.O. Silva, Sarah M. Mardon, Gulbin Gurdal
Coal Combustion and Gasification Products Journal Archive
There is an international need for a variety of lanthanide elements (rare earth elements, or REEs) in modern electronic and related components. This has led to a desire to broaden production from both previously productive locations and to expand production to new sources, possibly including coal-derived fly ash. The concentration of lanthanides in coal-combustion fly ash depends on a number of factors, one of the most important being the concentration of the elements in the feed coal. Unlike some elements, such as Zn and As, the REE concentration is largely not a function of element volatility. In this study, we …
Fouling Intensity Of Three Indian Coals, S. Balakrishnan, R. Nagarajan
Fouling Intensity Of Three Indian Coals, S. Balakrishnan, R. Nagarajan
Coal Combustion and Gasification Products Journal Archive
Ash particles can arrive at heat-transfer surfaces either in solid (solidified) state or in molten state, depending on the factors such as location inside the boiler, temperature, and residence time. In this study, arrival of ash particles in solid state, which can occur in the convective section of the boiler, was considered. Apart from the inertial force that drives particles .10 mmto the surface, the low-melting inorganic alkali vapors play a vital role in deposit formation by promoting sticking. Chemical equilibrium calculations were performed to calculate the equilibrium composition of flue gas, as well as the amount of condensable inorganic …
Chemical Weathering And Mobility Of Inorganic Species In Dry Disposed Ash: An Insight From Geochemical Fractionation And Physicochemical Analysis, S.A. Akinyemi, W.M. Gitari, A. Akinlua, L.F. Petrik
Chemical Weathering And Mobility Of Inorganic Species In Dry Disposed Ash: An Insight From Geochemical Fractionation And Physicochemical Analysis, S.A. Akinyemi, W.M. Gitari, A. Akinlua, L.F. Petrik
Coal Combustion and Gasification Products Journal Archive
The burning of low-grade coal produces vast amounts of ash and other solid by-products. In South Africa, coal combustion by-products undergo disposal on land as dry heaps or slurried to dams. In this study, the geochemical partitioning, transport, and mobility of elements in dry disposed ash dumps were investigated using a modified sequential extraction scheme. The chemical and mineralogical compositions of 50 drilled core samples were investigated by X-ray fluorescence (XRF), X-ray diffraction (XRD), and inductively coupled plasma mass spectrometry. Ternary plots of major elements as determined by XRF showed that the 15-year-old and 2-week-old dry disposed ashes are sialic, …
Microstructural And Mineralogical Transformation Of Hydraulically Disposed Fly Ash—Implications To The Environment, Jabulani S. Mahlaba, Elsabe P. Kearsley, Richard A. Kruger
Microstructural And Mineralogical Transformation Of Hydraulically Disposed Fly Ash—Implications To The Environment, Jabulani S. Mahlaba, Elsabe P. Kearsley, Richard A. Kruger
Coal Combustion and Gasification Products Journal Archive
Increasing amounts of coal are combusted annually to meet the ever-increasing energy demands. The inevitable by-products include fly ash and saline effluents, which require acceptable disposal. The aim of this article is to compare the effect of hydraulic disposal with dry ash dumping. The results indicate that the former carries more environmental benefits based on the physical, chemical, and mineralogical aspects that were investigated.
Cordyline Fruticosa Growth And Soil Microbial Quality With Topical Application Of Coal Combustion By-Products Aggregates, Sangchul Hwang, Isomar Latorre, Eileen Irizarry
Cordyline Fruticosa Growth And Soil Microbial Quality With Topical Application Of Coal Combustion By-Products Aggregates, Sangchul Hwang, Isomar Latorre, Eileen Irizarry
Coal Combustion and Gasification Products Journal Archive
Coal combustion by-products aggregates (CCAs) are a solidified composite of fly and bottom ashes (2:1, by wt). Here, we assessed the feasibility of beneficial use of CCAs as a soil amendment or conditioner by conducting an outdoor experiment with Cordyline fruticosa (lucky plant) to determine its growth and soil microbial quality under the influence of topical CCA application (95 tons ha21). Enhanced growth of C. fruticosa with CCA application was noted, with respect to plant height, growth rate, leaf size, and leaf chlorophyll intensity. Soil dehydrogenase activity and total heterotrophic bacteria count were greater with topical CCA application, especially in …
Influence Of Activator Solution Formulation On Fresh And Hardened Properties Of Low-Calcium Fly Ash Geopolymer Concrete, Carlos Montes, Erez N. Allouche
Influence Of Activator Solution Formulation On Fresh And Hardened Properties Of Low-Calcium Fly Ash Geopolymer Concrete, Carlos Montes, Erez N. Allouche
Coal Combustion and Gasification Products Journal Archive
The effect of the composition of activator solutions on fresh and hardened properties of geopolymer concrete was investigated. Research variables included liquid sodium silicate product (DH, NH, and StarH), sodium hydroxide molar concentration (6, 10, and 14), and sodium silicate–to–sodium hydroxide ratio (1, 2, and 3). Response variables were compressive strength, corrosion resistance expressed as remaining compressive strength and mass loss, and flowability. Results were analyzed using Minitab statistical software. Findings suggest that activator solution formulation has a significant effect on the properties of the resulting geopolymer binder. The experimental design used was found effective in establishing the optimum activator …
Mineralogical Transformations In Coal Feedstocks During Carbon Conversion, Based On Packed-Bed Combustor Tests: Part 2. Behavior Of Individual Particles, Ratale H. Matjie, Colin R. Ward, Zhongsheng Li
Mineralogical Transformations In Coal Feedstocks During Carbon Conversion, Based On Packed-Bed Combustor Tests: Part 2. Behavior Of Individual Particles, Ratale H. Matjie, Colin R. Ward, Zhongsheng Li
Coal Combustion and Gasification Products Journal Archive
Handpicked carbon-rich particles (coal or char), mineral-rich particles (heated stones), and bonded stone aggregates (clinkers) from the upper and lower parts of a pilot-scale packed-bed combustor bed, designed to simulate conversion or combustion processes, were subjected to mineralogical and inorganic geochemical studies, in order to evaluate the reactions that may occur during carbon conversion at a particle-by-particle scale. The mineral matter of the carbon-rich particles was found to have higher proportions of carbonate minerals and kaolinite than the mineral-rich (stone) particles in the coal feedstocks used in the study, and to form phases such as anorthite, gehlenite, pyrrhotite, troilite, and …
Mineralogical Transformations In Coal Feedstocks During Carbon Conversion, Based On Packed-Bed Combustor Tests: Part 1. Bulk Coal And Ash Studies, Ratale H. Matjie, Colin R. Ward, Zhongsheng Li
Mineralogical Transformations In Coal Feedstocks During Carbon Conversion, Based On Packed-Bed Combustor Tests: Part 1. Bulk Coal And Ash Studies, Ratale H. Matjie, Colin R. Ward, Zhongsheng Li
Coal Combustion and Gasification Products Journal Archive
Mineralogical and inorganic geochemical studies have been carried out on composite samples of six different coarse-crushed (,120 mm) feed coals tested in a pilot-scale packed-bed combustor designed to simulate conversion and some fixed-bed combustion processes, and also on composite samples of the ashes produced. The mineral matter of the coals consisted mainly of quartz, kaolinite, and Ca-bearing carbonate minerals (calcite, dolomite, aragonite), with minor proportions of illite, pyrite, and several other phases, along with some Ca in an organically associated form. The base to acid ratio of the coal ashes ranged from 0.1 to 0.3, due mainly to variations in …
Potential Indoor Air Exposures And Health Risks From Mercury Off-Gassing Of Coal Combustion Products Used In Building Materials, Christopher M. Long, Sonja N. Sax, Ari S. Lewis
Potential Indoor Air Exposures And Health Risks From Mercury Off-Gassing Of Coal Combustion Products Used In Building Materials, Christopher M. Long, Sonja N. Sax, Ari S. Lewis
Coal Combustion and Gasification Products Journal Archive
Coal combustion products (CCPs), including coal fly ash (CFA) and flue gas desulfurization (FGD) gypsum, have gained accepted use as substitutes for traditional substances in building materials. Because of the presence of mercury (Hg) in CCP materials, some concerns have been raised regarding the potential for Hg to off-gas from building materials into indoor air. Risk assessment offers a well-accepted, objective framework in which to determine whether such off-gassing could result in humanexposures of health concern. We thus conducted a screening-level human health risk assessment to estimate worst-case inhalation risks from indoor air exposures to Hg for multiple CCP utilization …
Quantifying The Benefits Of Using Flue Gas Desulfurization Gypsum In Sustainable Wallboard Production, Jin Cheol Lee, Sabrina L. Bradshaw, Tuncer B. Edil, Craig H. Benson
Quantifying The Benefits Of Using Flue Gas Desulfurization Gypsum In Sustainable Wallboard Production, Jin Cheol Lee, Sabrina L. Bradshaw, Tuncer B. Edil, Craig H. Benson
Coal Combustion and Gasification Products Journal Archive
Electric utilities produce more than 11.2 Mt of flue gas desulfurization (FGD) gypsum annually. Approximately 7.5 Mt is used in wallboard production. This article examines the environmental and cost benefits associated with replacement of natural gypsum in wallboard with FGD gypsum. A life-cycle analysis program was used to quantify the benefits of using FGD gypsum from electric power production in wallboard construction. Comparisons were made between energy consumption, water use, and greenhouse gas (GHG) emissions associated with obtaining and processing virgin gypsum material and those with FGD gypsum. The added impact of disposing of the unused FGD gypsum in landfills …
Waste Classification Of Slag Generated In A Pilot-Scale Entrained-Flow Gasifier, Ashleigh Cousins, Robin W. Hughes, David J. Mccalden, Dennis Y. Lu, Edward J. Anthony
Waste Classification Of Slag Generated In A Pilot-Scale Entrained-Flow Gasifier, Ashleigh Cousins, Robin W. Hughes, David J. Mccalden, Dennis Y. Lu, Edward J. Anthony
Coal Combustion and Gasification Products Journal Archive
Series of gasification tests have been completed in the pilot-scale entrained-flow slagging gasifier at CanmetENERGY using Canadian coals, oil-sand coke, and blends of these fuels to determine if the produced slags are nonhazardous in nature. Solid wastes generated during these tests were analyzed for their trace metals, crystallinity, and toxic constituent leaching tendency in an attempt to provide more insight into the possibility of disposal or by-product use of gasifier-produced solid waste. The gasification tests were performed at conditions representative of commercial gasifiers using a dry-fuel-feed configuration. The lower-volatility elements were found to partition between the slag and process-water solids …