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Sample records for fly ash solvent

  1. Solvent extraction separation of copper and zinc from MSWI fly ash leachates.

    PubMed

    Tang, Jinfeng; Steenari, Britt-Marie

    2015-10-01

    Fly ash from combustion of municipal solid waste (MSW) contains significant amounts of metals, some of which are valuable and some of which are potentially toxic. This type of ash is most often stabilized and landfilled which means that the metals will be difficult to reclaim at a later stage. In recent years efforts have been made to develop feasible methods to recover selected metals, such as Zn, from MSW fly ash. If this would be possible, a significant amount of valuable metals could be re-inserted in the industrial material loops. This paper describes the development and evaluation of a process for recovery of Cu and Zn from MSW combustion fly ash based on hydrochloric acid leaching followed by two solvent extraction processes, one for each metal. The separation of Cu from the acid leachate was done using an aldoxime extractant, LIX860N-I, in kerosene and a mixture of phosphine oxides, Cyanex 923, also in kerosene, was used for extraction of Zn from the Cu-depleted aqueous phase. The extraction of Cu was selective, but a significant amount of other metals, such as Fe and Pb, were co-extracted together with Zn. It was shown that it is possible to decrease the contamination of Fe by using a suitable concentration of nitric acid solution for stripping or by removing the contaminating metals through cementation. The suggested process was tested for two MSW combustion fly ashes in laboratory scale experiments and gave Cu yields of 69-87% and Zn yields of 75-80% based on the contents in the ash.

  2. Interaction of planar and nonplanar organic contaminants with coal fly ash: Effects of polar and nonpolar solvent solutions

    SciTech Connect

    Burgess, R.M.; Ryba, S.A.; Cantwell, M.G.; Gundersen, J.L.; Tien, R.; Perron, M.M.

    2006-08-15

    Coal fly ash has a very high sorption capacity for a variety of anthropogenic contaminants and has been used to cleanse wastewater of pollutants for approximately 40 years. Like other black carbons, the planar structure of the residual carbon in fly ash results in elevated affinities for planar organic contaminants, such as polycyclic aromatic hydrocarbons (PAHs) and some polychlorinated biphenyls (PCBs). The present study was performed to understand better the mechanisms affecting the strong interaction between planar contaminants and coal fly ash. The removal of 10 PCBs and 10 PAHs by several fly ashes and other sorbents was evaluated under different experimental conditions to highlight the intermolecular forces influencing adsorption. Varying fly ash concentration and solvent system composition indicated that dispersive interactions were most prevalent. For the PCBs, empirical results also were compared to molecular modeling estimates of the energy necessary for the PCB molecule to assume a planar conformation (PCe). The PCe levels ranged from 8 to 25 kcal/mol, depending on the degree of ortho-substituted chlorination of the PCB. A significant correlation between PCe and PCB removal from solution was observed for the fly ashes and activated carbon, whereas the nonplanar sorbent octadecyl (C{sub 18}) indicated no relationship. These findings demonstrate the strong interaction between black carbon fly ash and planar organic contaminants. Furthermore, as exemplified by the PCBs, these results show how this interaction is a function of a contaminant's ability to assume a planar conformation.

  3. Hydrometallurgical recovery of germanium from coal gasification fly ash. Solvent extraction method

    SciTech Connect

    Arroyo, F.; Fernandez-Pereira, C.

    2008-05-15

    This article is concerned with a simple hydrometallurgical method for the selective recovery of germanium from fly ash (FA) generated in an integrated gasification with combined cycle (IGCC) process. The method is based on the leaching of FA with water and a subsequent concentration and selective separation of germanium by a solvent method. Regarding the leaching step, the different operational conditions studied were liquid/solid (L/S) ratio and time of contact. The solvent extraction method was based on germanium complexation with catechol (CAT) in an aqueous solution followed by the extraction of the Ge-CAT complex with an extracting organic reagent diluted in an organic solvent. The main factors examined during the extraction tests were aqueous phase/organic phase (AP/OP) volumetric ratio, aqueous phase pH, amounts of reagents, and time of contact. Germanium extraction yields were higher than 90%. Alkaline and acid stripping of organic extracts were studied obtaining the best results with 1M NaOH (85%). A high-purity germanium solution was obtained. Experimental data presented in this work show that the extraction of germanium by the solvent method designed can be selective toward germanium, and this element can be effectively separated from arsenic, molybdenum, nickel, antimony, vanadium, and zinc.

  4. Vanadium recovery from oil fly ash by leaching, precipitation and solvent extraction processes.

    PubMed

    Navarro, R; Guzman, J; Saucedo, I; Revilla, J; Guibal, E

    2007-01-01

    In order to reduce the environmental impact due to land disposal of oil fly ash from power plants and to valorize this waste material, the removal of vanadium was investigated using leaching processes (acidic and alkaline treatments), followed by a second step of metal recovery from leachates involving either solvent extraction or selective precipitation. Despite a lower leaching efficiency (compared to sulfuric acid), sodium hydroxide was selected for vanadium leaching since it is more selective for vanadium (versus other transition metals). Precipitation was preferred to solvent extraction for the second step in the treatment since: (a) it is more selective; enabling complete recovery of vanadate from the leachate in the form of pure ammonium vanadate; and (b) stripping of the loaded organic phase (in the solvent extraction process) was not efficient. Precipitation was performed in a two-step procedure: (a) aluminum was first precipitated at pH 8; (b) then ammonium chloride was added at pH 5 to bring about vanadium precipitation.

  5. Vanadium recovery from oil fly ash by leaching, precipitation and solvent extraction processes

    SciTech Connect

    Navarro, R.; Guzman, J.; Saucedo, I.; Guibal, E.

    2007-07-01

    In order to reduce the environmental impact due to land disposal of oil fly ash from power plants and to valorize this waste material, the removal of vanadium was investigated using leaching processes (acidic and alkaline treatments), followed by a second step of metal recovery from leachates involving either solvent extraction or selective precipitation. Despite a lower leaching efficiency (compared to sulfuric acid), sodium hydroxide was selected for vanadium leaching since it is more selective for vanadium (versus other transition metals). Precipitation was preferred to solvent extraction for the second step in the treatment since: (a) it is more selective; enabling complete recovery of vanadate from the leachate in the form of pure ammonium vanadate; and (b) stripping of the loaded organic phase (in the solvent extraction process) was not efficient. Precipitation was performed in a two-step procedure: (a) aluminum was first precipitated at pH 8; (b) then ammonium chloride was added at pH 5 to bring about vanadium precipitation.

  6. Activation of fly ash

    DOEpatents

    Corbin, D.R.; Velenyi, L.J.; Pepera, M.A.; Dolhyj, S.R.

    1986-08-19

    Fly ash is activated by heating a screened magnetic fraction of the ash in a steam atmosphere and then reducing, oxidizing and again reducing the hydrothermally treated fraction. The activated fly ash can be used as a carbon monoxide disproportionating catalyst useful in the production of hydrogen and methane.

  7. Activation of fly ash

    DOEpatents

    Corbin, David R.; Velenyi, Louis J.; Pepera, Marc A.; Dolhyj, Serge R.

    1986-01-01

    Fly ash is activated by heating a screened magnetic fraction of the ash in a steam atmosphere and then reducing, oxidizing and again reducing the hydrothermally treated fraction. The activated fly ash can be used as a carbon monoxide disproportionating catalyst useful in the production of hydrogen and methane.

  8. Fly ash carbon passivation

    DOEpatents

    La Count, Robert B; Baltrus, John P; Kern, Douglas G

    2013-05-14

    A thermal method to passivate the carbon and/or other components in fly ash significantly decreases adsorption. The passivated carbon remains in the fly ash. Heating the fly ash to about 500 and 800 degrees C. under inert gas conditions sharply decreases the amount of surfactant adsorbed by the fly ash recovered after thermal treatment despite the fact that the carbon content remains in the fly ash. Using oxygen and inert gas mixtures, the present invention shows that a thermal treatment to about 500 degrees C. also sharply decreases the surfactant adsorption of the recovered fly ash even though most of the carbon remains intact. Also, thermal treatment to about 800 degrees C. under these same oxidative conditions shows a sharp decrease in surfactant adsorption of the recovered fly ash due to the fact that the carbon has been removed. This experiment simulates the various "carbon burnout" methods and is not a claim in this method. The present invention provides a thermal method of deactivating high carbon fly ash toward adsorption of AEAs while retaining the fly ash carbon. The fly ash can be used, for example, as a partial Portland cement replacement in air-entrained concrete, in conductive and other concretes, and for other applications.

  9. Extraction of bituminous coal fly ash for polynuclear aromatic hydrocarbons: evaluation of modified and unmodified supercritical fluid extraction, enhanced fluidity solvents, and accelerated solvent extraction.

    PubMed

    Kenny, D V; Olesik, S V

    1998-02-01

    A comparison among supercritical fluid extraction (SFE), modified SFE, enhanced-fluidity extraction, and accelerated solvent extraction (ASE) techniques was made for the extraction of polynuclear aromatic hydrocarbons (PAHs) from an aged, spiked bituminous coal fly ash. Non-ASE extraction techniques used in this study could not recover PAHs with molecular weights greater than that of pyrene. ASE techniques using methylene chloride (with and without a static step) and toluene were able to recover most of the PAHs studied. None of the ASE techniques could quantitatively extract the low-molecular-weight PAHs from the bituminous fly ash. The medium-molecular-weight PAHs were best recovered with toluene ASE. The high-molecular-weight PAHs were best recovered with the toluene ASE technique (> 80%), but the overall precision of these measurements was low. Methylene chloride ASE with a static step recovered the high-molecular-weight PAHs with the next highest efficiency (approximately 55%) and had standard deviations less than 10% (longer extraction times [> 30 min] with the methylene chloride would increase the recoveries of these analytes.) A comparison of the results from this study with those of a previous study using lignite coal fly ash illustrates the difficulty in developing and adapting analyte-specific extraction methods for analytes that are adsorbed on different matrices.

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

    EPA Science Inventory

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

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

    EPA Science Inventory

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

  12. Fly ash quality and utilization

    SciTech Connect

    Barta, L.E.; Lachner, L.; Wenzel, G.B.; Beer, M.J.

    1995-12-01

    The quality of fly ash is of considerable importance to fly ash utilizers. The fly ash puzzolanic activity is one of the most important properties that determines the role of fly ash as a binding agent in the cementing process. The puzzolanic activity, however is a function of fly ash particle size and chemical composition. These parameters are closely related to the process of fly ash formation in pulverized coal fired furnaces. In turn, it is essential to understand the transformation of mineral matter during coal combustion. Due to the particle-to-particle variation of coal properties and the random coalescence of mineral particles, the properties of fly ash particles e.g. size, SiO{sub 2} content, viscosity can change considerably from particle to particle. These variations can be described by the use of the probability theory. Since the mean values of these randomly changing parameters are not sufficient to describe the behavior of individual fly ash particles during the formation of concrete, therefore it is necessary to investigate the distribution of these variables. Examples of these variations were examined by the Computer Controlled Scanning Electron Microscopy (CCSEM) for particle size and chemical composition for Texas lignite and Eagel Butte mineral matter and fly ash. The effect of combustion on the variations of these properties for both the fly ash and mineral matter were studied by using a laminar flow reactor. It is shown in our paper, that there are significant variations (about 40-50% around the mean values) of the above-listed properties for both coal samples. By comparing the particle size and chemical composition distributions of the mineral matter and fly ash, it was possible to conclude that for the Texas lignite mineral matter, the combustion did not effect significantly the distribution of these properties, however, for the Eagel Butte coal the combustion had a major impact on these mineral matter parameters.

  13. Extraction of lignite coal fly ash for polynuclear aromatic hydrocarbons: modified and unmodified supercritical fluid extraction, enhanced-fluidity solvents, and accelerated solvent extraction.

    PubMed

    Kenny, D V; Olesik, S V

    1998-02-01

    A comparison among modified and unmodified supercritical fluid extraction (SFE), enhanced-fluidity liquid extraction, and accelerated solvent extraction (ASE) techniques was made for the extraction of polynuclear aromatic hydrocarbons (PAHs) from an aged, spiked lignite coal fly ash. All of the attempted extraction conditions allowed the extraction of the PAHs to some degree, but no single extraction technique proved to be superior for all of the PAHs used. Three groups of PAHs with similar extraction efficiencies were identified. The group with the lowest molecular weights was best recovered using a 90% CO2-10% methanol mixture at 70 degrees C and 238 atm. The group of medium-molecular-weight PAHs was recovered equally well using any of three extraction conditions: SFE (100% CO2, 90 degrees C, and 238 atm), enhanced-fluidity liquid mixture (60% CO2-40% methanol, 70 degrees C, and 238 atm), and a methanol ASE mixture. The group of high-molecular-weight PAHs seemed to be equally well recovered with all of the attempted extraction conditions, but the enhanced-fluidity conditions (60% CO2-40% methanol, 70 degrees C, and 238 atm) had extraction recoveries (> 85%) with the lowest standard deviations (approximately 5%).

  14. Using fly ash for construction

    SciTech Connect

    Valenti, M.

    1995-05-01

    Each year electrical utilities generate 80 million tons of fly ash, primarily from coal combustion. Typically, utilities dispose of fly ash by hauling it to landfills, but that is changing because of the increasing cost of landfilling, as well as environmental regulations. Now, the Electric Power Research Institute (EPRI), in Palo Alto, Calif., its member utilities, and manufacturers of building materials are finding ways of turning this energy byproduct into the building blocks of roads and structures by converting fly ash into construction materials. Some of these materials include concrete and autoclaved cellular concrete (ACC, also known as aerated concrete), flowable fill, and light-weight aggregate. EPRI is also exploring uses for fly ash other than in construction materials. One of the more high-end uses for the material is in metal matrix composites. In this application, fly ash is mixed with softer metals, such as aluminum and magnesium, to strengthen them, while retaining their lighter weight.

  15. Phosphate-Bonded Fly Ash.

    DTIC Science & Technology

    1994-12-09

    FCODE OC ______________ ARLINGTON VA 22217-5660 - dis~bu~i.19~ 3 B Navy Case No. 75,787 PATENTS PHOSPHATE -BONDED FLY ASH IN’NA G. TALMY DEBORAH A. HAUGHT...2 3 , CaO. MgO, etc. with which the H.PO4 reacts to form the polymer-like phosphate bonds which hold the fly ash particles together. In the second...conventional means. The moisture (water) content of the aqueous HP0 4 /fly ash mixture is preferably from about 3 to about 5 weight percent for semidry

  16. Fly ash chemical classification based on lime

    SciTech Connect

    Fox, J.

    2007-07-01

    Typically, total lime content (CaO) of fly ash is shown in fly ash reports, but its significance is not addressed in US specifications. For certain applications a low lime ash is preferred. When a class C fly ash must be cementitious, lime content above 20% is required. A ternary S-A-C phase diagram pilot is given showing the location of fly ash compositions by coal rank and source in North America. Fly ashes from subbituminous coal from the Powder River Basin usually contain sufficient lime to be cementitious but blending with other coals may result in calcium being present in phases other than tricalcium aluminate. 9 refs., 1 fig.

  17. Petrographic characterization of economizer fly ash

    SciTech Connect

    Valentim, B.; Hower, J.C.; Soares, S.; Guedes, A.; Garcia, C.; Flores, D.; Oliveira, A.

    2009-11-15

    Policies for reducing NOx emissions have led power plants to restrict O{sub 2}, resulting in high-carbon fly ash production. Therefore, some potentially useful fly ash, such as the economizer fly ash, is discarded without a thorough knowledge of its composition. In order to characterize this type of fly ash, samples were collected from the economizer Portuguese power plant burning two low-sulfur bituminous coals. Characterization was also performed on economizer fly ash subsamples after wet sieving, density and magnetic separation. Analysis included atomic absorption spectroscopy, loss-on-ignition, scanning electron microscopy/energy-dispersive X-ray spectroscopy, optical microscopy, and micro-Raman spectroscopy.

  18. Utilization of coal fly ash. Master's thesis

    SciTech Connect

    Openshaw, S.C.

    1992-01-01

    Coal-fired power plants produce approximately 80 million tons of fly ash each year. Efforts to use fly ash have reached only a twenty to thirty percent reutilization rate. A literature review was performed to provide a consensus of the available information regarding fly ash. Fly ash is highly variable depending on the coal source, plant operations, and several other parameters. The various fly ash characteristics are discussed including classifications, physical characteristics, chemical properties and chemical compositions. Although extensive research has been performed on the use of fly ash, very little of this research has monitored any environmental impacts. The environmental concerns addressed include mobilization of toxic elements, biota impact, microbial impact, handling dangers, and pertinent regulations. Finally, the various disposal and reutilization options for fly ash are examined. A recommendation is provided for further research to cover deficiencies found in the literature.

  19. Plasma vitrification of fly ash

    SciTech Connect

    Beudin, V.; Guihard, B.; Pineau, D.; Labrot, M.; Soler, G.; Favier, J.M.; Boudeau, A.

    1995-12-31

    This paper presents the plasma vitrification of fly-ash produced by a Municipal Waste Incinerator, as programmed by Europlasma Company in France. It describes the main assumptions, technical and economical data and regulations taken into account to build and operate the first industrial pilot plant from 1995, near Bordeaux (France), using a non transferred plasma torch of 500 kW operated with air.

  20. ACAA fly ash basics: quick reference card

    SciTech Connect

    2006-07-01

    Fly ash is a fine powdery material created when coal is burned to generate electricity. Before escaping into the environment via the utility stacks, the ash is collected and may be stored for beneficial uses or disposed of, if necessary. The use of fly ash provides environmental benefits, such as the conservation of natural resources, the reduction of greenhouse gas emissions and eliminating the needed for ash disposal in landfills. It is also a valuable mineral resource that is used in construction and manufacturing. Fly ash is used in the production of Portland cement, concrete, mortars and stuccos, manufactured aggregates along with various agricultural applications. As mineral filler, fly ash can be used for paints, shingles, carpet backing, plastics, metal castings and other purposes. This quick reference card is intended to provide the reader basic source, identification and composition, information specifically related to fly ash.

  1. Application of water as a solvent in microwave-assisted extraction for analysis of PCBs and CBzs in fly ash.

    PubMed

    Sun, Yifei; Takaoka, Masaki; Takeda, Nobuo; Matsumoto, Tadao; Oshita, Kazuyuki

    2005-04-01

    Polychlorinated biphenyls (PCBs) and chlorobenzenes (CBzs) are two classes of dioxin precursors formed in municipal solid waste incinerators (MSWIs); they produce negative health effects similar to those of dioxins. Reducing the analytical time required for determining the concentrations of these compounds in MSWIs is important for quickly evaluating their importance and assessing associated health risks. In the present study, water is used as a safe and environmentally friendly solvent in microwave-assisted extraction (MAE) for PCB and CBz analyses. MAE is compared with traditional Soxhlet extraction (SE) to determine the extraction efficiencies. The evaluation of extraction efficiencies shows that MAE has a high extraction efficiency compared with that of SE when water content is lower than 60%. Furthermore, the extraction time and organic solvent consumption are reduced with MAE compared with SE.

  2. Physicochemical characterization of Spanish fly ashes

    SciTech Connect

    Querol, X.; Umana, J.C.; Alastuey, A.; Bertrana, C.; Lopez-Soler, A.; Plana, F.

    1999-12-01

    This article summarizes the results obtained from the physical, chemical, and mineralogical characterization of 14 fly ash samples. Major features that influence the utilization of each fly ash for zeolite synthesis are evidenced, and several fly ash types were selected as potential high-quality starting material for zeolite synthesis and ceramic applications. The main parameters influencing this selection were relatively small grain size; high Al and Si contents; high glass content; low CaO, S, and Fe contents; and relatively low heavy metal concentration. The Compostilla and Cou He fly ashes have high potential applications because of the low content of major impurities (such as Ca, Fe, and S) and the low content of soluble hazardous elements. The Espiel, Escucha, Los Barrios, As Pontes, Soto de Ribera, Meirama, Narcea, and Teruel fly ashes have important application potential, but this potential is slightly limited by the intermediate content of nonreactive impurities, such as Fe and Ca. The La Robla fly ash is of moderate interest, since the relatively high Ca and Fe oxide contents may reduce its potential applications. Finally, the Puertollano fly ash also has limited application because of the very high concentration of some heavy metals such as As, Cd, Ge, Hg, Pb, and Zn. From a mineralogical point of view, the Compostilla, Espiel, and Soto de Ribera fly ashes show the highest aluminum-silicate glass content and, consequently, the highest industrial application potential.

  3. Treatment of fly ash for use in concrete

    DOEpatents

    Boxley, Chett [Park City, UT

    2012-05-15

    A process for treating fly ash to render it highly usable as a concrete additive. A quantity of fly ash is obtained that contains carbon and which is considered unusable fly ash for concrete based upon foam index testing. The fly ash is mixed with a quantity of spray dryer ash (SDA) and water to initiate a geopolymerization reaction and form a geopolymerized fly ash. The geopolymerized fly ash is granulated. The geopolymerized fly ash is considered usable fly ash for concrete according to foam index testing. The geopolymerized fly ash may have a foam index less than 40%, and in some cases less than 20%, of the foam index of the untreated fly ash. An optional alkaline activator may be mixed with the fly ash and SDA to facilitate the geopolymerization reaction. The alkaline activator may contain an alkali metal hydroxide, carbonate, silicate, aluminate, or mixtures thereof.

  4. Adsorptive properties of fly ash carbon

    SciTech Connect

    Graham, U.M.; Robl, T.L.; Rathbone, R.F.

    1996-12-31

    The driving force behind the development of this research project has been the increasing concerns about the detrimental effects of high carbon carryover into combustion ash. Without the carbon, combustion ash can be utilized in cement industry avoiding environmental implications in landfill operations. Because the carbon surfaces have been structurally altered while passing through the combustor, including the formation of a macro-porous surface, fly ash carbons, after separation from the ash, may constitute a unique precursor for the production of adsorbents. This paper discusses a novel approach for using fly ash carbons in the cleanup of organic pollutants.

  5. Fly ash beneficiation by carbon burnout

    SciTech Connect

    Cochran, J.W.; Boyd, T.J.

    1995-03-01

    The CBO process for fly ash beneficiation shows excellent potential. Values derived from avoided disposal costs, revenue from fly ash sales, environmental attributes and the ability to process 100% of the ash indicate the potential market for this process. Work has begun on the next phase of process development and commercialization and includes site specific application studies (technical and economic investigations for specific sites). Demonstration plant designs at approximately 100,000 TPY are being considered by several participating utilities.

  6. Treatment of fly ash for use in concrete

    DOEpatents

    Boxley, Chett [Park City, UT; Akash, Akash [Salt lake City, UT; Zhao, Qiang [Natick, MA

    2012-05-08

    A process for treating fly ash to render it highly usable as a concrete additive. A quantity of fly ash is obtained that contains carbon and which is considered unusable fly ash for concrete based upon foam index testing. The fly ash is mixed with an activator solution sufficient to initiate a geopolymerization reaction and for a geopolymerized fly ash. The geopolymerized fly ash is granulated. The geopolymerized fly ash is considered usable fly ash for concrete according to foam index testing. The geopolymerized fly ash may have a foam index less than 35% of the foam index of the untreated fly ash, and in some cases less than 10% of the foam index of the untreated fly ash. The activator solution may contain an alkali metal hydroxide, carbonate, silicate, aluminate, or mixtures thereof.

  7. Treatment of fly ash for use in concrete

    DOEpatents

    Boxley, Chett; Akash, Akash; Zhao, Qiang

    2013-01-08

    A process for treating fly ash to render it highly usable as a concrete additive. A quantity of fly ash is obtained that contains carbon and which is considered unusable fly ash for concrete based upon foam index testing. The fly ash is mixed with an activator solution sufficient to initiate a geopolymerization reaction and for a geopolymerized fly ash. The geopolymerized fly ash is granulated. The geopolymerized fly ash is considered usable fly ash for concrete according to foam index testing. The geopolymerized fly ash may have a foam index less than 35% of the foam index of the untreated fly ash, and in some cases less than 10% of the foam index of the untreated fly ash. The activator solution may contain an alkali metal hydroxide, carbonate, silicate, aluminate, or mixtures thereof.

  8. Erodibility of fly ash-treated minesoils

    SciTech Connect

    Gorman, J.M.; Sencindiver, J.C.; Singh, R.N.

    1997-12-31

    Fly ash, a by-product of coal-fired power plants, has been used successfully in reclaiming adverse mine sites such as abandoned mine lands by improving minesoil chemical and physical properties. But, the fine sand-silt particle size of fly ash may make it more susceptible to detachment and transport by erosive processes. Furthermore, the high content of silt-size particles in fly ash may make it more susceptable to surface crust formation resulting in reduced infiltration and increased surface runoff and erosion. In the summer of 1989, fly ash/wood waste mixtures were surface applied on two separate mine sites, one with 10% slope and the other 20% slope, in central Preston County, West Virginia. Erosion rates were measured directly using the Linear Erosion/Elevation Measuring Instrument (LEMI). Erosion measurements were taken during the first two growing seasons on both sites. Erosion values were up to five times greater on the fly ash-treated minesoil than on the minesoil without fly ash cover. Mulching with wood chips reduced fly ash erosion to about one-half the loss of the unmulched plots. Erosion was related to both the amount and type of ground cover. Increased vegetative ground cover resulted in reduced erosion. Mosses and fungi appeared to provide better erosion protection than grass-legume cover.

  9. Leaching characteristics of lead from melting furnace fly ash generated by melting of incineration fly ash.

    PubMed

    Okada, Takashi; Tomikawa, Hiroki

    2012-11-15

    This study investigated the effect of the chemical composition of incineration fly ash on the leaching characteristics of Pb from melting furnace fly ash generated by melting incineration fly ash. Melting furnace fly ash from both a real-scale melting process and lab-scale melting experiments was analyzed. In addition, the theoretical behavior of Cl that affects the leaching characteristics of Pb was simulated by a thermodynamic equilibrium calculation. Proportions of water-soluble Pb in the melting furnace fly ash were correlated with equivalent ratios of total Pb in the ash and Cl transferred to gas. The amount of Cl in the gas increased with an increase in the molar ratio of Cl to Na and K in the incineration fly ash. The thermodynamic calculation predicted that HCl generation is promoted by the increase in the molar ratio, and X-ray photoelectron spectroscopy indicated a possible presence of PbCl(2) in the melting furnace fly ash. These results implied that the formation of water-soluble PbCl(2) with HCl was affected by the relationships among the amounts of Na, K, and Cl in the incineration fly ash. This is highly significant in determining the leaching characteristics of Pb from the melting furnace fly ash. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Fly ash enhanced metal removal process

    SciTech Connect

    Nonavinakere, S.; Reed, B.E.

    1995-12-31

    The primary objective of the study was to evaluate the effectiveness of fly ashes from local thermal power plants in the removal of cadmium, nickel, chromium, lead, and copper from aqueous waste streams. Physical and chemical characteristics of fly ashes were determined, batch isotherm studies were conducted. A practical application of using fly ash in treating spent electroless nickel (EN) plating baths by modified conventional precipitation or solid enhanced metal removal process (SEMR) was investigated. In addition to nickel the EN baths also contains completing agents such as ammonium citrate and succinic acid reducing agents such as phosphate and hypophosphite. SEMR experiments were conducted at different pHs, fly ash type and concentrations, and settling times.

  11. Fly ash disposal in a limestone quarry

    SciTech Connect

    Peffer, J.R.

    1982-05-01

    Approximately 740 000 tons of eastern bituminous coal fly ash were deposited at the abandoned Zullinger limestone quarry from 1973-1980. The quarry extended below the water table and was not lined to isolate the ash from the aquifer. Long-term groundwater pollution has apparently not resulted.

  12. Salt-thermal zeolitization of fly ash.

    PubMed

    Choi, C L; Park, M; Lee, D H; Kim, I E; Park, B Y; Choi, J

    2001-07-01

    The molten-salt method has been recently proposed as a new approach to zeolitization of fly ash. Unlike the hydrothermal method, this method employs salt mixtures as the reaction medium without any addition of water. In this study, systematic investigation has been conducted on zeolitization of fly ash in a NaOH-NaNO3 system in order to elucidate the mechanism of zeolite formation and to achieve its optimization. Zeolitization of fly ash was conducted by thermally treating a powder mixture of fly ash, NaOH, and NaNO3. Zeolitization of fly ash took place above 200 degrees C, a temperature lower than the melting points of salt and base in the NaOH-NaNO3 system. However, it was uncertain whether the reactions took place in a local molten state or in a solid state. Therefore, the proposed method is renamed the "salt-thermal" method rather than the "molten-salt" method. Mainly because of difficulty in mobility of components in salt mixtures, zeolitization seems to occur within a local reaction system. In situ rearrangement of activated components seems to lead to zeolite formation. Particle growth, rather than crystal growth through agglomeration, resulted in no distinct morphologies of zeolite phases. Following are the optimal zeolitization conditions of the salt-thermal method: temperature, 250-350 degrees C; time, 3-12 h; weight ratio of NaOH/NaNO3, 0.3-0.5; weight ratio of NaNO3/fly ash, 0.7-1.4. Therefore, it is clear from this work that the salt-thermal method could be applied to massive zeolitization of fly ash as a new alternative method for recycling this waste.

  13. Mechanical treatment of fly ashes. Part 1: Physico-chemical characterization of ground fly ashes

    SciTech Connect

    Paya, J.; Monzo, J.; Borrachero, M.V.; Peris-Mora, E.

    1995-10-01

    Physico-chemical characteristics of mechanically treated fly ashes are investigated. An original fly ash was ground, using a laboratory mill, for several times (from 10 to 60 minutes). Respect to physical characterization, fineness increasing of samples with grinding time was observed, but loss of effectiveness occurred for grinding time longer than 20 minutes. Ground samples showed higher specific gravity probably due to the presence of cenospheres in the original fly ash. Only a little change in mineralogical composition of fly ashes was observed when grinding: calcium carbonate formation by reaction of calcium oxide with carbon dioxide. Chemical behavior (pH and conductivity) of fly ash/water suspensions were studied and acid neutralization capacities measured.

  14. Extraction of trace metals from fly ash

    DOEpatents

    Blander, Milton; Wai, Chien M.; Nagy, Zoltan

    1984-01-01

    A process for recovering silver, gallium and/or other trace metals from a fine grained industrial fly ash associated with a process for producing phosphorous, the fly ash having a silicate base and containing surface deposits of the trace metals as oxides, chlorides or the like, with the process being carried out by contacting the fly ash with AlCl.sub.3 in an alkali halide melt to react the trace metals with the AlCl.sub.3 to form compositions soluble in the melt and a residue containing the silicate and aluminum oxide or other aluminum precipitate, and separating the desired trace metal or metals from the melt by electrolysis or other separation techniques.

  15. Extraction of trace metals from fly ash

    DOEpatents

    Blander, M.; Wai, C.M.; Nagy, Z.

    1983-08-15

    A process is described for recovering silver, gallium and/or other trace metals from a fine grained industrial fly ash associated with a process for producing phosphorous. The fly ash has a silicate base and contains surface deposits of the trace metals as oxides, chlorides or the like. The process is carried out by contacting the fly ash with AlCl/sub 3/ in an alkali halide melt to react the trace metals with the AlCl/sub 3/ to form compositions soluble in the melt and a residue containing the silicate and aluminum oxide or other aluminum precipitate, and separating the desired trace metal or metals from the melt by electrolysis or other separation techniques.

  16. Size dependent cytotoxicity of fly ash particles

    SciTech Connect

    Liu, W.K.; Tam, J.S.K.; Wong, M.H.

    1988-01-01

    Fly ash samples were collected from the electrostatic precipitator of a coal-fired power plant in Hong Kong. The particles of the respirable range (smaller than 10 {mu}m) were divided into 4 groups according to their particle size (mass median aerodynamic diameters). The surface morphology and the metal contents (Fe, Mn, Al and Zn) of fly ash particles were examined by a scanning electron microscopy and an inductively coupled plasma spectrophotometer, respectively. The particles were very heterogeneous in size and shape as well as the concentration of metals. The cytotoxicity of these four groups of fly ash particles were evaluated using an in vitro rat alveolar macrophages culture assay. The viability of alveolar macrophages was lower when incubated with smaller size particles. This relationship was also reflected by the damage of the surface morphology of the cells and the release of cytoplasmic (lactate dehydrogenase) and lysosomal (acid phosphatase and {beta}-glucuronidase) marker enzymes into the culture media.

  17. Fly ash system technology improves opacity

    SciTech Connect

    2007-06-15

    Unit 3 of the Dave Johnston Power Plant east of Glenrock, WY, USA had problems staying at or below the opacity limits set by the state. The unit makes use of a Lodge Cottrell precipitator. When the plant changed to burning Power River Basin coal, ash buildup became a significant issue as the fly ash control system was unable to properly evacuate hoppers on the unit. To overcome the problem, the PLC on the unit was replaced with a software optimization package called SmartAsh for the precipitator fly ash control system, at a cost of $500,000. After the upgrade, there have been no plugged hoppers and the opacity has been reduced from around 20% to 3-5%. 2 figs.

  18. Fly Ash Characteristics and Carbon Sequestration Potential

    SciTech Connect

    Palumbo, Anthony V.; Amonette, James E.; Tarver, Jana R.; Fagan, Lisa A.; McNeilly, Meghan S.; Daniels, William L.

    2007-07-20

    Concerns for the effects of global warming have lead to an interest in the potential for inexpensive methods to sequester carbon dioxide (CO2). One of the proposed methods is the sequestration of carbon in soil though the growth of crops or forests.4,6 If there is an economic value placed on sequestration of carbon dioxide in soil there may be an an opportunity and funding to utilize fly ash in the reclamation of mine soils and other degraded lands. However, concerns associated with the use of fly ash must be addressed before this practice can be widely adopted. There is a vast extent of degraded lands across the world that has some degree of potential for use in carbon sequestration. Degraded lands comprise nearly 2 X 109 ha of land throughout the world.7 Although the potential is obviously smaller in the United States, there are still approximately 4 X 106 ha of degraded lands that previously resulted from mining operations14 and an additional 1.4 X 108 ha of poorly managed lands. Thus, according to Lal and others the potential is to sequester approximately 11 Pg of carbon over the next 50 years.1,10 The realization of this potential will likely be dependent on economic incentives and the use of soil amendments such as fly ash. There are many potential benefits documented for the use of fly ash as a soil amendment. For example, fly ash has been shown to increase porosity, water-holding capacity, pH, conductivity, and dissolved SO42-, CO32-, HCO3-, Cl- and basic cations, although some effects are notably decreased in high-clay soils.8,13,9 The potential is that these effects will promote increased growth of plants (either trees or grasses) and result in greater carbon accumulation in the soil than in untreated degraded soils. This paper addresses the potential for carbon sequestration in soils amended with fly ash and examines some of the issues that should be considered in planning this option. We describe retrospective studies of soil carbon accumulation on

  19. Changeing of fly ash leachability after grinding

    NASA Astrophysics Data System (ADS)

    Lakatos, J.; Szabo, R.; Racz, A.; Banhidi, O.; Mucsi, G.

    2016-04-01

    Effect of grinding on the reactivity of fly ash used for geopolymer production was tested. Extraction technique using different alkaline and acidic solutions were used for detect the change of the solubility of elements due to the physical and mechano-chemical transformation of minerals in function of grinding time. Both the extraction with alkaline and acidic solution have detected improvement in solubility in function of grinding time. The enhancement in alkaline solution was approx. 100% in case of Si and Al. The acidic medium able to dissolve the fly ash higher manner than the alkaline, therefore the effect of grinding was found less pronounced.

  20. Using fly ash to mitigate explosions

    SciTech Connect

    Taulbee, D.

    2008-07-01

    In 2005 the University of Kentucky's Center for Applied Energy Research was given funding to evaluate the use of coal combustion by-products (CCBs) to reduce the explosive potential of ammonium nitrate (AN) fertilizers. Fly ash C (FAC), fly ash F (FAF) and flue gas desulfurization by-product (FGD) were evaluated. It was found that applying a CCB coating to the AN particles at concentrations of 5 wt% or greater prevented the AN explosion from propagating. The article reports on results so far and outlines further work to be done. 6 figs.

  1. Fly ash as an adsorbent for wastewater treatment

    SciTech Connect

    Shao, J.; Wang, Z.; Shao, X.; Li, H.

    1997-12-31

    Fly ash is a kind of finely divided residue that results from the combustion of ground or powdered coal in power stations. The production of large amount of fly ash causes serious environmental problems. The grain size of fly ash is very small. Fly ash has high specific surface and high porosity. The contents of active components, active silicon and aluminum, are high too. So, fly ash has high adsorptivity. Wastewater contains amounts of inorganic and organic materials that pollute the environments. Normal adsorbent, such as activated carbon, has a high cost and a complex production technique. Fly ash can adsorb many materials in wastewater and it can partly substitute for activated carbon. When fly ash is used in wastewater treatment, it can bring about economic and social benefits. As a kind of adsorbent, fly ash has good results for decolorization, deodorization, organic matter removal, COD removal, defluorization, dephosporization, heavy metal removal, and pH modification in wastewater treatment processes.

  2. Eco-friendly fly ash utilization: potential for land application

    SciTech Connect

    Malik, A.; Thapliyal, A.

    2009-07-01

    The increase in demand for power in domestic, agricultural, and industrial sectors has increased the pressure on coal combustion and aggravated the problem of fly ash generation/disposal. Consequently the research targeting effective utilization of fly ash has also gained momentum. Fly ash has proved to be an economical substitute for expensive adsorbents as well as a suitable raw material for brick manufacturing, zeolite synthesis, etc. Fly ash is a reservoir of essential minerals but is deficient in nitrogen and phosphorus. By amending fly ash with soil and/or various organic materials (sewage sludge, bioprocess materials) as well as microbial inoculants like mycorrhizae, enhanced plant growth can be realized. Based on the sound results of large scale studies, fly ash utilization has grown into prominent discipline supported by various internationally renowned organizations. This paper reviews attempts directed toward various utilization of fly ash, with an emphasis on land application of organic/microbial inoculants amended fly ash.

  3. A comparative study on the recovery of polycyclic aromatic hydrocarbons from fly ash and lignite coal.

    PubMed

    Arditsoglou, Anastasia; Terzi, Eleni; Kalaitzoglou, Maria; Samara, Constantini

    2003-01-01

    The recovery of polycyclic aromatic hydrocarbons (PAHs) from lignite coal burnt in Greek power stations and the fly ash produced is examined comparatively using Soxhlet, ultrasonic and accelerated solvent extraction procedures with various organic solvents. Soxhlet using toluene/methanol mixture and accelerated solvent extraction/toluene were found to be the most efficient methods for fly ash PAHs, yielding average recoveries of about 80%. The accelerated solvent extraction/toluene procedure was superior for lignite PAHs, yielding 96% average recovery, whereas ultrasonic and Soxhlet extraction yielded relatively lower recoveries (75% and 67%, respectively).

  4. 46 CFR 148.225 - Calcined pyrites (pyritic ash, fly ash).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Calcined pyrites (pyritic ash, fly ash). 148.225 Section... § 148.225 Calcined pyrites (pyritic ash, fly ash). (a) This part does not apply to the shipment of calcined pyrites that are the residual ash of oil or coal fired power stations. (b) This section applies...

  5. 46 CFR 148.225 - Calcined pyrites (pyritic ash, fly ash).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Calcined pyrites (pyritic ash, fly ash). 148.225 Section... § 148.225 Calcined pyrites (pyritic ash, fly ash). (a) This part does not apply to the shipment of calcined pyrites that are the residual ash of oil or coal fired power stations. (b) This section applies...

  6. 46 CFR 148.225 - Calcined pyrites (pyritic ash, fly ash).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Calcined pyrites (pyritic ash, fly ash). 148.225 Section... § 148.225 Calcined pyrites (pyritic ash, fly ash). (a) This part does not apply to the shipment of calcined pyrites that are the residual ash of oil or coal fired power stations. (b) This section applies...

  7. 46 CFR 148.225 - Calcined pyrites (pyritic ash, fly ash).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Calcined pyrites (pyritic ash, fly ash). 148.225 Section... § 148.225 Calcined pyrites (pyritic ash, fly ash). (a) This part does not apply to the shipment of calcined pyrites that are the residual ash of oil or coal fired power stations. (b) This section applies...

  8. Alkali ash material: a novel fly ash-based cement.

    PubMed

    Rostami, Hossein; Brendley, William

    2003-08-01

    The United States generates 110 million t of coal ash annually. Approximately 70 million t of this coal ash is fly ash, of which 27% is recycled and the remaining 73% is landfilled. Disposal of such a huge quantity of ash poses a significant environmental problem. A new cementitious material has been developed, called alkali ash material (AAM), which is used to produce concrete for construction. AAM can be used to create a variety of concrete strengths and could revolutionize the concrete product manufacturing industry due to its economic advantage. AAM contains 40-95% Class F fly ash and is used as cement to bind sand, stone, and fibers creating concrete. AAM concrete has been tested for strength, durability, mechanical properties, and, most importantly, economic viability. AAM concrete is economically and technically viable for many construction applications. Some properties include rapid strength gain (90% of ultimate in 1 d), high ultimate strengths (110 MPa or 16,000 psi in 1 d), excellent acid resistance, and freeze-thaw durability. AAM's resistance to chemical attack, such as sulfuric (H2SO4), nitric (HNO3), hydrochloric (HCl), and organic acids, is far better than portland cement concrete. AAM is resistant to freeze-thaw attack based on ASTM C-666 specifications. Potential immediate applications of AAM are blocks, pipe, median barriers, sound barriers, and overlaying materials. Eventual markets are high strength construction products, bridge beams, prestressed members, concrete tanks, highway appurtenances, and other concrete products.

  9. Potential products from North Dakota lignite fly ash. Final report

    SciTech Connect

    Anderson, G R

    1980-06-01

    Four major areas where fly ash can be used are explored. Concrete building blocks with fly ash replacing 50% of the portland cement have proven to be successful using current ASTM standards. Results in the ceramics area show that a ceramic-like product using fly ash and crushed glass with a small amount of clay as a green binder. Some preliminary results using sulfur ash in building materials are reported and with results of making wallboard from ash. (MHR)

  10. Hydrothermal reaction of fly ash. Final report

    SciTech Connect

    Brown, P.W.

    1994-12-31

    The reactions which occur when fly ash is treated under hydrothermal conditions were investigated. This was done for the following primary reasons. The first of these is to determine the nature of the phases that form to assess the stabilities of these phases in the ambient environment and, finally, to assess whether these phases are capable of sequestering hazardous species. The second reason for undertaking this study was whether, depending on the composition of the ash and the presence of selected additives, it would be possible under hydrothermal conditions to form compounds which have cementitious properties. Formation of four classes of compounds, which bracket likely fly ash compositional ranges, were selected for study. The classes are calcium silicate hydrates, calcium selenates, and calcium aluminosulfates, and silicate-based glasses. Specific compounds synthesized were determined and their stability regions assessed. As part of stability assessment, the extent to which selected hazardous species are sequestered was determined. Finally, the cementing properties of these compounds were established. The results obtained in this program have demonstrated that mild hydrothermal conditions can be employed to improve the reactivity of fly ash. Such improvements in reactivity can result in the formation of monolithic forms which may exhibit suitable mechanical properties for selected applications as building materials. If the ashes involved are considered hazardous, the mechanical properties exhibited indicated the forms could be handled in a manner which facilitates their disposal.

  11. Mutagenicity of fly ash particles in Paramecium

    SciTech Connect

    Smith-Sonneborn, J.; Palizzi, R.A.; Herr, C.; Fisher, G.L.

    1981-01-09

    Paramecium, a protozoan that ingests nonnutritive particulate matter, was used to determine the mutagenicity of fly ash. Heat treatment inactivated mutagens that require metabolic conversion to their active form but did not destroy all mutagenicity. Extraction of particles with hydrochloric acid, but not dimethyl sulfoxide, removed detectable mutagenic activity.

  12. FLY ASH RECYCLE IN DRY SCRUBBING

    EPA Science Inventory

    The paper describes the effects of fly ash recycle in dry scrubbing. (Previous workers have shown that the recycle of product solids improves the utilization of slaked lime--Ca(OH)2--for sulfur dioxide (SO2) removal by spray dryers with bag filters.) In laboratory-scale experimen...

  13. FLY ASH RECYCLE IN DRY SCRUBBING

    EPA Science Inventory

    The paper describes the effects of fly ash recycle in dry scrubbing. (Previous workers have shown that the recycle of product solids improves the utilization of slaked lime--Ca(OH)2--for sulfur dioxide (SO2) removal by spray dryers with bag filters.) In laboratory-scale experimen...

  14. Flue gas desulfurization gypsum and fly ash

    SciTech Connect

    Not Available

    1992-05-01

    The Cumberland Fossil Plant (CUF) is located in Stewart County, Tennessee, and began commercial operation in 1972. This is the Tennessee Valley Authority`s newest fossil (coal-burning) steam electric generating plant. Under current operating conditions, the plant burns approximately seven million tons of coal annually. By-products from the combustion of coal are fly ash, approximately 428,000 tons annually, and bottom ash, approximately 115,000 tons annually. Based on historical load and projected ash production rates, a study was initially undertaken to identify feasible alternatives for marketing, utilization and disposal of ash by-products. The preferred alternative to ensure that facilities are planned for all by-products which will potentially be generated at CUF is to plan facilities to handle wet FGD gypsum and dry fly ash. A number of different sites were evaluated for their suitability for development as FGD gypsum and ash storage facilities. LAW Engineering was contracted to conduct onsite explorations of sites to develop information on the general mature of subsurface soil, rock and groundwater conditions in the site areas. Surveys were also conducted on each site to assess the presence of endangered and threatened species, wetlands and floodplains, archaeological and cultural resources, prime farmland and other site characteristics which must be considered from an environmental perspective.

  15. Synthesis of hydroxy sodalite from coal fly ash using waste industrial brine solution.

    PubMed

    Musyoka, Nicholas M; Petrik, Leslie F; Balfour, Gillian; Gitari, Wilson M; Hums, Eric

    2011-01-01

    The effect of using industrial waste brine solution instead of ultra pure water was investigated during the synthesis of zeolites using three South African coal fly ashes as Si feedstock. The high halide brine was obtained from the retentate effluent of a reverse osmosis mine water treatment plant. Synthesis conditions applied were; ageing of fly ash was at 47 ° C for 48 hours, and while the hydrothermal treatment temperature was set at 140 ° C for 48 hours. The use of brine as a solvent resulted in the formation of hydroxy sodalite zeolite although unconverted mullite and hematite from the fly ash feedstock was also found in the synthesis product.

  16. Explosibility boundaries for fly ash/pulverized fuel mixtures.

    PubMed

    Dastidar, A G; Amyotte, P R

    2002-05-27

    Incomplete combustion and subsequent fuel contamination of a waste stream can pose a serious explosion hazard. An example of this type of incident is the contamination of fly ash with unburned pulverized coal. The coal, if present in sufficient quantities in the mixture, can act as a fuel source for a potential explosion. Experiments were conducted in a 20l Siwek explosibility test chamber to determine the minimum fuel contamination of fly ash required to form an explosible mixture. A sample of fly ash from Ontario Power Generation (OPG) (Ont., Canada) was artificially contaminated with Pittsburgh pulverized coal dust (the surrogate used to represent unburned fuel dust). Additionally, the influence of fly ash particle size on the amount of fuel contaminant required to form an explosible mixture was examined. Fine and coarse size fractions of fly ash were obtained by screening the original sample of OPG fly ash. The results show that at least 21% Pittsburgh pulverized coal (or 10% volatile matter) was required to form an explosible mixture of the original fly ash sample and coal dust. The results also illustrate that fly ash particle size is important when examining the explosibility of the mixture. The fine size fraction of fly ash required a minimum of 25% coal dust (12% volatile matter) in the mixture for explosibility, whereas the coarse fly ash required only 10% coal dust (7% volatile matter). Thus, the larger the particle size of the inert fly ash component in the mixture, the greater the hazard.

  17. The catalytic and photocatalytic activity of coal fly ashes

    NASA Astrophysics Data System (ADS)

    Dlugi, Ralph; Güsten, Hans

    Great differences in the catalytic and photocatalytic activity of two samples of fly ash from two different coal-fired power plants have been demonstrated to exist for two reactions of environmental significance, namely, the heterogeneous SO 2 oxidation in a smog chamber and the photochemical degradation of two polynuclear aromatic hydrocarbons adsorbed onto the fly ashes. At a relative humidity (r.h.) of 80%, the reaction rate for the heterogeneous SO 2 oxidation on an acidic fly ash (pH 5.65) is ten times higher than for the oxidation on a fly ash of pH 9.3. Compared to silica gel, the 'acidic' fly ash gives rise to a faster photocatalytic degradation of anthracene and phenanthrene, while the same aromatic hydrocarbons are highly resistant to photodegradation when adsorbed on the fly ash of pH 9.3. Possible explanations and environmental consequences of the differing catalytic activity of fly ashes are discussed.

  18. Possibilities of municipal solid waste incinerator fly ash utilisation.

    PubMed

    Hartmann, Silvie; Koval, Lukáš; Škrobánková, Hana; Matýsek, Dalibor; Winter, Franz; Purgar, Amon

    2015-08-01

    Properties of the waste treatment residual fly ash generated from municipal solid waste incinerator fly ash were investigated in this study. Six different mortar blends with the addition of the municipal solid waste incinerator fly ash were evaluated. The Portland cement replacement levels of the municipal solid waste incinerator fly ash used were 25%, 30% and 50%. Both, raw and washed municipal solid waste incinerator fly ash samples were examined. According to the mineralogical composition measurements, a 22.6% increase in the pozzolanic/hydraulic properties was observed for the washed municipal solid waste incinerator fly ash sample. The maximum replacement level of 25% for the washed municipal solid waste incinerator fly ash in mortar blends was established in order to preserve the compressive strength properties. Moreover, the leaching characteristics of the crushed mortar blend was analysed in order to examine the immobilisation of its hazardous contents.

  19. Characteristics of the transfer of fly ash utilization technology

    SciTech Connect

    Yue, B.; Nieel, E.; Raats, M.

    1997-12-31

    In the Netherlands, the total amount of fly ash produced from power generating plants lies between 900,000 and 1,000,000 tons per year. Since 1986, a 100% fly ash utilization has been achieved as a high quality raw material for the building materials industry. In China, the present fly ash production capacity is approximately 100 million tons per year. The share of fly ash used by the building materials industry is less then 15% of the total fly ash production. In this presentation, efforts are made to illustrate the difference in characteristics between the Dutch and the Chinese approach towards the fly ash utilization problem. Government policy, environmental legislation and an active involvement of the power industry have been, amongst others, three crucial factors for the successful utilization of fly ash in the Netherlands. It is believed that some of the Dutch experiences might also be applicable in China.

  20. Wastewater sludge conditioning by fly ash

    SciTech Connect

    Wang, X.; Viraraghavan, T.

    1998-09-01

    Conditioning wastewater sludge from the City of Regina Wastewater Treatment Plant by fly ash from Boundary Dam Power Station, Saskatchewan, Canada, was studied. Toxicity characteristic leaching procedure (TCLP), equilibrium leach test (ELT), and long-term leaching test (LTLT) were used to investigate the leachability of heavy metals. Results from these leaching tests indicated that, on the basis of concentrations of microorganisms and heavy metals (Cd, Cr, Cu, Ni and Zn), the sludge produced at the Regina Wastewater Treatment Plant conditioned by the locally available fly ash can be disposed of in landfills and used as a soil conditioner for land application. Sorption, and silicate and hydroxide precipitations were considered to be the three important mechanisms in fixation of heavy metals. High pH conditions were considered to be the predominant mechanism in killing microorganisms.

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

    PubMed

    Zimmer, A; Bergmann, C P

    2007-01-01

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

  2. Manufacture of ceramic tiles from fly ash

    DOEpatents

    Hnat, James G.; Mathur, Akshay; Simpson, James C.

    1999-01-01

    The present invention relates to a process for forming glass-ceramic tiles. Fly ash containing organic material, metal contaminants, and glass forming materials is oxidized under conditions effective to combust the organic material and partially oxidize the metallic contaminants and the glass forming materials. The oxidized glass forming materials are vitrified to form a glass melt. This glass melt is then formed into tiles containing metallic contaminants.

  3. Manufacture of ceramic tiles from fly ash

    DOEpatents

    Hnat, J.G.; Mathur, A.; Simpson, J.C.

    1999-08-10

    The present invention relates to a process for forming glass-ceramic tiles. Fly ash containing organic material, metal contaminants, and glass forming materials is oxidized under conditions effective to combust the organic material and partially oxidize the metallic contaminants and the glass forming materials. The oxidized glass forming materials are vitrified to form a glass melt. This glass melt is then formed into tiles containing metallic contaminants. 6 figs.

  4. Element bioaccumulation from coal fly ash

    SciTech Connect

    James, W.D.; Ogugbuaja, V.O.

    1986-01-01

    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.

  5. Fly ash and concrete: a study determines whether biomass, or coal co-firing fly ash, can be used in concrete

    SciTech Connect

    Wang, Shuangzhen; Baxter, Larry

    2006-08-01

    Current US national standards for using fly ash in concrete (ASTM C618) state that fly ash must come from coal combustion, thus precluding biomass-coal co-firing fly ash. The co-fired ash comes from a large and increasing fraction of US power plants due to rapid increases in co-firing opportunity fuels with coal. The fly ashes include coal fly ash, wood fly ash from pure wood combustion, biomass and coal co-fired fly ash SW1 and SW2. Also wood fly ash is blended with Class C or Class F to produce Wood C and Wood E. Concrete samples were prepared with fly ash replacing cement by 25%. All fly ash mixes except wood have a lower water demand than the pure cement mix. Fly ashes, either from coal or non coal combustion, increase the required air entraining agent (AEA) to meet the design specification of the mixes. If AEA is added arbitrarily without considering the amount or existence of fly ash results could lead to air content in concrete that is either too low or too high. Biomass fly ash does not impact concrete setting behaviour disproportionately. Switch grass-coal co-fired fly ash and blended wood fly ash generally lie within the range of pure coal fly ash strength. The 56 day flexure strength of all the fly ash mixes is comparable to that of the pure cement mix. The flexure strength from the coal-biomass co-fired fly ash does not differ much from pure coal fly ash. All fly ash concrete mixes exhibit lower chloride permeability than the pure cement mixes. In conclusion biomass coal co-fired fly ash perform similarly to coal fly ash in fresh and hardened concrete. As a result, there is no reason to exclude biomass-coal co-fired fly ash in concrete.

  6. Treatment of fly ash from power plants using thermal plasma.

    PubMed

    Al-Mayman, Sulaiman; AlShunaifi, Ibrahim; Albeladi, Abdullah; Ghiloufi, Imed; Binjuwair, Saud

    2017-01-01

    Fly ash from power plants is very toxic because it contains heavy metals. In this study fly ash was treated with a thermal plasma. Before their treatment, the fly ash was analyzed by many technics such as X-ray fluorescence, CHN elemental analysis, inductively coupled plasma atomic emission spectroscopy and scanning electron microscopy. With these technics, the composition, the chemical and physical proprieties of fly ash are determined. The results obtained by these analysis show that fly ash is mainly composed of carbon, and it contains also sulfur and metals such as V, Ca, Mg, Na, Fe, Ni, and Rh. The scanning electron microscopy analysis shows that fly ash particles are porous and have very irregular shapes with particle sizes of 20-50 μm. The treatment of fly ash was carried out in a plasma reactor and in two steps. In the first step, fly ash was treated in a pyrolysis/combustion plasma system to reduce the fraction of carbon. In the second step, the product obtained by the combustion of fly ash was vitrified in a plasma furnace. The leaching results show that the fly ash was detoxified by plasma vitrification and the produced slag is amorphous and glassy.

  7. Treatment of fly ash from power plants using thermal plasma

    PubMed Central

    Al-Mayman, Sulaiman; AlShunaifi, Ibrahim; Albeladi, Abdullah; Binjuwair, Saud

    2017-01-01

    Fly ash from power plants is very toxic because it contains heavy metals. In this study fly ash was treated with a thermal plasma. Before their treatment, the fly ash was analyzed by many technics such as X-ray fluorescence, CHN elemental analysis, inductively coupled plasma atomic emission spectroscopy and scanning electron microscopy. With these technics, the composition, the chemical and physical proprieties of fly ash are determined. The results obtained by these analysis show that fly ash is mainly composed of carbon, and it contains also sulfur and metals such as V, Ca, Mg, Na, Fe, Ni, and Rh. The scanning electron microscopy analysis shows that fly ash particles are porous and have very irregular shapes with particle sizes of 20–50 μm. The treatment of fly ash was carried out in a plasma reactor and in two steps. In the first step, fly ash was treated in a pyrolysis/combustion plasma system to reduce the fraction of carbon. In the second step, the product obtained by the combustion of fly ash was vitrified in a plasma furnace. The leaching results show that the fly ash was detoxified by plasma vitrification and the produced slag is amorphous and glassy. PMID:28546898

  8. The performance and application of fly ash modified by PDMDAAC.

    PubMed

    Cao, X Y; Yue, Q Y; Song, L Y; Li, M; Zhao, Y C

    2007-08-17

    Fly ash modification by polydimethydiallylammonium chloride (PDMDAAC) in laboratory scale was explored in this work and the adsorption performance of modified fly ash and its application in dyeing wastewater treatment were also studied. The key factors (concentration and temperature) for PDMDAAC to affect the adsorption properties of fly ash (FA) were revealed using the orthogonal test with four factors. The results indicated that the adsorption magnitude of fly ash to PDMDAAC increased due to its favorable specific surface causing the change of the surface charge nature. Hence, adsorption performance of modified fly ash on organic molecules and its ion exchange capacity are strengthened. The maximum color removal efficiency was obtained as 88.2% by modified fly ash with 2.0 g/100 mL dosage in dyeing wastewater, which is much higher than 12.5% color removal efficiency by raw fly ash with the same dosage. And, the used modified fly ash could be used for cement production as additive agent. The intensity of cement produced with 15% the modified fly ash in weight reached the Chinese Cement Standard (GB/T17671-1999), blazing a promising novel way in fly ash utilization.

  9. Stabilizing soft fine-grained soils with fly ash

    SciTech Connect

    Edil, T.B.; Acosta, H.A.; Benson, C.H.

    2006-03-15

    The objective of this study was to evaluate the effectiveness of self-cementing fly ashes derived from combustion of subbituminous coal at electric power plants for stabilization of soft fine-grained soils. California bearing ratio (CBR) and resilient modulus (M{sub r}) tests were conducted on mixtures prepared with seven soft fine-grained soils (six inorganic soils and one organic soil) and four fly ashes. The soils were selected to represent a relatively broad range of plasticity, with plasticity indices ranging between 15 and 38. Two of the fly ashes are high quality Class C ashes (per ASTM C 618) that are normally used in Portland cement concrete. The other ashes are off-specification ashes, meaning they do not meet the Class C or Class F criteria in ASTM C 618. Tests were conducted on soils and soil-fly ash mixtures prepared at optimum water content (a standardized condition), 7% wet of optimum water content (representative of the typical in situ condition in Wisconsin), and 9-18% wet of optimum water content (representative of a very wet in situ condition). Addition of fly ash resulted in appreciable increases in the CBR and M{sub r} of the inorganic soils. For water contents 7% wet of optimum, CBRs of the soils alone ranged between 1 and 5. Addition of 10% fly ash resulted in CBRs ranging between 8 and 17, and 18% fly ash resulted in CBRs between 15 and 31. Similarly, M{sub r} of the soil alone ranged between 3 and 15 MPa at 7% wet of optimum, whereas addition of 10% fly ash resulted in M{sub r} between 12 and 60 MPa and 18% fly ash resulted in M{sub r} between 51 and 106 MPa. In contrast, except for one fly ash, addition of fly ash generally had little effect on CBR or M{sub r} of the organic soil.

  10. Sorbate characteristics of fly ash. Volume I. Final report

    SciTech Connect

    Liskowitz, J.W.; Grow, J.; Sheih, M.; Trattner, R.; Kohut, J.; Zwillenberg, M.

    1983-08-01

    The objective of this investigation is to correlate the sorbate and leaching characteristics of fly ash with coal properties and monitored combustion conditions in order to design a system for the inexpensive treatment of industrial wastes and leachate from industrial landfills using mixtures of fly ash as inexpensive sorbents. Such a low-cost treatment system could also treat ash pond effluent for water reuse by powerplants as cooling tower makeup. Twelve unblended coals from 10 different mines were burned under monitored conditions in three different types of coal fired boilers in order to determine the influence of coal composition, ash fusion temperatures, boiler additives, combustion conditions and co-firing of natural gas or oil with the coal, on the leaching and sorbate characteristics of the fly ash produced. This included the determination of: (1) SiO/sub 2/, Al/sup 2/O/sub 3/, Fe/sub 2/O/sub 3/, CaO, K/sub 2/O, Na/sub 2/O, MgO, sulfur, ash fusion temperatures Ti, Cd, Sn, Ni, Pb, Mo, Cu, Cr, n, Mn, Ba and V in the coals and their respective fly ashes and bottom ashes; (2) Moessbauer spectra of a number of coals and their fly ashes; and (3) surface analysis of the fly ashes using ESCA. The leaching exhibited by the fly ashes with regard to pH, Cd, B, Sn, Ni, Pb, Mo, Cu, Cr, Mn and Fe was examined. In addition, the removal of Cd, B, Sn, Ni, Pb, Mo, Cu, Cr, Fe, As and organics by fly ash was evaluated, using from actual ash pond samples to model realistic inlet concentrations. The results show that fly ash can be used for the treatment of Cadmium, Boron, Tin, Molybdenum, Nickel, Lead, Copper, Chromium, Zinc, Manganese, Iron, Arsenic and organics in actual ash pond effluents. 18 references, 64 figures, 60 tables.

  11. Recovery of aluminum and other metal values from fly ash

    DOEpatents

    McDowell, W.J.; Seeley, F.G.

    1979-11-01

    The invention relates to a method for improving the acid leachability of aluminum and other metal values found in fly ash which comprises sintering the fly ash, prior to acid leaching, with a calcium sulfate-containing composition at a temperature at which the calcium sulfate is retained in said composition during sintering and for a time sufficient to quantitatively convert the aluminum in said fly ash into an acid-leachable form.

  12. Recovery of aluminum and other metal values from fly ash

    DOEpatents

    McDowell, William J.; Seeley, Forest G.

    1981-01-01

    The invention described herein relates to a method for improving the acid leachability of aluminum and other metal values found in fly ash which comprises sintering the fly ash, prior to acid leaching, with a calcium sulfate-containing composition at a temperature at which the calcium sulfate is retained in said composition during sintering and for a time sufficient to quantitatively convert the aluminum in said fly ash into an acid-leachable form.

  13. Market opportunities for fly ash fillers in North America

    SciTech Connect

    Eckert, C.; Harris, T.; Gledhill, J. )

    1990-11-01

    Direct Acid Leaching (DAL) processed fly ash is derived from treating raw and beneficiated coal fly ash with hydrochloric acid. The DAL process allows for the production of fly ash with greater chemical purity and consistency than raw fly ash alone. In addition, DAL fly ash is similar to various minerals used in a wide range of applications that require filler minerals. This project investigates the feasibility of using three grades of DAL fly ash ranging from 10 microns to 30 microns in diameter as an alternative filler material to mineral fillers. Six major applications in North America, requiring large volumes of filler minerals were investigated by region including: (1) asphalt roofing shingles (2) carpet backing (3) joint compound and wallboard (4) industrial coatings (5) plastics (6) vinyl flooring. It is determined that calcium carbonate was the primary mineral filler DAL fly ash would be competing with in the applications investigated. Calcium carbonate is used in all applications investigated. The application which demonstrated the greatest potential for using DAL fly ash is asphalt shingles. Asphalt shingles were the largest calcium carbonate consuming application identified, consuming 4.8 million tons in 1988, and is the least sensitive to the dark color of the DAL fly ash. Although the DAL fly ash typically has a smaller particle size, in comparison to calcium carbonate, the asphalt shingle manufacturers felt it would be a good substitute. Other promising applications for DAL fly ash were industrial coatings and plastics where the calcium carbonate particle size requirements of 3 to 6 microns very closely matches the particle size of the DAL fly ash considered in this project. 17 figs., 36 tabs.

  14. Kinetics of beneficiated fly ash by carbon burnout

    SciTech Connect

    Okoh, J.M.; Dodoo, J.N.D.; Diaz, A.; Ferguson, W.; Udinskey, J.R. Jr.; Christiana, G.A.

    1997-12-31

    The presence of carbon in fly ash requires an increase in the dosage of the air-entraining admixture for concrete mix, and may cause the admixture to lose efficiency. Specifying authorities for the concrete producers have set maximum allowable levels of residual carbon. These levels are the so called Loss On Ignition (LOI). The concrete producers` day-to-day purchasing decisions sets the LOI at 4%. The objective of the project is to investigate the kinetics of oxidation of residual carbon present in coal fly ash as a possible first step toward producing low-carbon fly ash from high-carbon, low quality fly ash.

  15. Sulfate resistance of high calcium fly ash concrete

    NASA Astrophysics Data System (ADS)

    Dhole, Rajaram

    Sulfate attack is one of the mechanisms which can cause deterioration of concrete. In general, Class C fly ash mixtures are reported to provide poor sulfate resistance. Fly ashes, mainly those belonging to the Class C, were tested as per the ASTM C 1012 procedure to evaluate chemical sulfate resistance. Overall the Class C fly ashes showed poor resistance in the sulfate environment. Different strategies were used in this research work to improve the sulfate resistance of Class C fly ash mixes. The study revealed that some of the strategies such as use of low W/CM (water to cementing materials by mass ratio), silica fume or ultra fine fly ash, high volumes of fly ash and, ternary or quaternary mixes with suitable supplementary cementing materials, can successfully improve the sulfate resistance of the Class C fly ash mixes. Combined sulfate attack, involving physical and chemical action, was studied using sodium sulfate and calcium sulfate solutions. The specimens were subjected to wetting-drying cycles and temperature changes. These conditions were found to accelerate the rate of degradation of concrete placed in a sodium sulfate environment. W/CM was found to be the main governing factor in providing sulfate resistance to mixes. Calcium sulfate did not reveal damage as a result of mainly physical action. Characterization of the selected fly ashes was undertaken by using SEM, XRD and the Rietveld analysis techniques, to determine the relation between the composition of fly ashes and resistance to sulfate attack. The chemical composition of glass represented on the ternary diagram was the main factor which had a significant influence on the sulfate resistance of fly ash mixtures. Mixes prepared with fly ashes containing significant amounts of vulnerable crystalline phases offered poor sulfate resistance. Comparatively, fly ash mixes containing inert crystalline phases such as quartz, mullite and hematite offered good sulfate resistance. The analysis of hydrated lime-fly

  16. Fly ash design manual for road and site applications

    SciTech Connect

    DiGioia, A.M. Jr.; Brendel, G.F.

    1992-04-01

    This design manual describes the use of fly ash as a construction material for use as structural and nonstructural fills, backfills, embankments, base courses, roller compacted concrete dams and pavements, soil stabilization, land reclamation and other high volume uses. The manual details the physical, engineering, and chemical properties of bituminous, subbituminous and lignite fly ash. Included are field and laboratory testing methods, design data, procedures and examples, specifications, quality control, and pre- and post-construction monitoring. Volume 1 describes uses where fly ash is used dry or conditioned with small amounts of moisture. Volume 2 describes uses where fly ash is placed as a slurry with relatively large amounts of water.

  17. Chemical constraints on fly ash glass compositions

    SciTech Connect

    John H. Brindle; Michael J. McCarthy

    2006-12-15

    The major oxide content and mineralogy of 75 European fly ashes were examined, and the major element composition of the glass phase was obtained for each. Correlation of compositional trends with the glass content of the ash was explored. Alkali content was deduced to have a major influence on glass formation, and this in turn could be related to the probable chemistry of clay minerals in the source coals. Maximal glass content corresponded to high aluminum content in the glass, and this is in accordance with the theoretical mechanism of formation of aluminosilicate glasses, in which network-modifying oxides are required to promote tetrahedral coordination of aluminum in glass chain structures. Iron oxide was found to substitute for alkali oxides where the latter were deficient, and some indications of preferred eutectic compositions were found. The work suggests that the proportion of the glass phase in the ash can be predicted from the coal mineralogy and that the utility of a given ash for processing into geopolymers or zeolites is determined by its source. 23 refs., 7 figs., 1 tab.

  18. Investigation on the fly ash thermal treatment on the performance of Lithium Ferriphosphate (LiFePO{sub 4}) battery

    SciTech Connect

    Febiolita, Bella; Khoirunnissak, Dewi; Purwanto, Agus

    2016-02-08

    Addition of the fly ash can be used to improve the capacity of LiFePO{sub 4} battery. Fly ash was added in Acethylene Black (AB) as 2% of the total weight of Acetylene Black (AB). The effects of temperature variation and fly ash characteristics were analyzed. Fly ash was prepared by heating at 50, 100, 150, and 250°C in muffle furnace for 5 hours and passed in 200 mesh screen prior to mixing it with other compounds. Lithium Ferriphospat (LiFePO{sub 4}), fly ash, Acethylene Black (AB), Polyvinylidene Fluoride (PVDF) as a binder and N-methyl-2-pyrrolidone (NMP) as a solvent were mixed to be slurry. The slurry were coated, dried and hot pressed to make a cathode film. The performance of battery lithium was examined by eight channel battery analyzer. The composition of the fly ash was examined by X-ray fluorescence spectrometry (XRF) and Fourier Tansform Infrared Spectroscopy (FTIR). The excellent performance was shown in the fly ash addition which were treated by heating at 150°C. The capacity of fly ash added LiFePO{sub 4} battery is 94.373 mAh/g, which is higher than that of without fly ash addition, i.e. 67.998 mAh/g.

  19. Investigation on the fly ash thermal treatment on the performance of Lithium Ferriphosphate (LiFePO4) battery

    NASA Astrophysics Data System (ADS)

    Febiolita, Bella; Khoirunnissak, Dewi; Purwanto, Agus

    2016-02-01

    Addition of the fly ash can be used to improve the capacity of LiFePO4 battery. Fly ash was added in Acethylene Black (AB) as 2% of the total weight of Acetylene Black (AB). The effects of temperature variation and fly ash characteristics were analyzed. Fly ash was prepared by heating at 50, 100, 150, and 250°C in muffle furnace for 5 hours and passed in 200 mesh screen prior to mixing it with other compounds. Lithium Ferriphospat (LiFePO4), fly ash, Acethylene Black (AB), Polyvinylidene Fluoride (PVDF) as a binder and N-methyl-2-pyrrolidone (NMP) as a solvent were mixed to be slurry. The slurry were coated, dried and hot pressed to make a cathode film. The performance of battery lithium was examined by eight channel battery analyzer. The composition of the fly ash was examined by X-ray fluorescence spectrometry (XRF) and Fourier Tansform Infrared Spectroscopy (FTIR). The excellent performance was shown in the fly ash addition which were treated by heating at 150°C. The capacity of fly ash added LiFePO4 battery is 94.373 mAh/g, which is higher than that of without fly ash addition, i.e. 67.998 mAh/g.

  20. Speciation of chromium in Australian fly ash.

    PubMed

    Narukawa, Tomohiro; Riley, Kenneth W; French, David H; Chiba, Koichi

    2007-08-15

    The concentrations of chromium (III) and (VI) in fly ash from nine Australian coal fired power stations were determined. Cr(VI) was completely leached by extraction with 0.01 M NaOH solution and the concentration was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). This was confirmed by determining Cr(III) and Cr(VI) in the extracts of fly ash that had been spiked with chromium salts. These analytical measurements were done using a combination of ion-exchange chromatography and ICP-AES. The elutant was 0.05 M HNO(3) containing 0.5%-CH(3)OH. When the column was operated at a flow rate of 1.2 ml min(-1) and samples were injected by use of a sample loop with a volume of 100 microl, Cr(III) and Cr(VI) in sample solution was exclusively separated within approximately 10 min. The detection limits (3sigma) were 5 ng for Cr(III) (0.050 mg l(-1)) and 9 ng for Cr(VI) (0.090 mg l(-1)), respectively. A relative standard deviation of 1.9% (n=6) was obtained for the determination by IC-ICP-AES of 0.25 mg l(-1) Cr(III) and Cr(VI).

  1. Properties of solid waste incinerator fly ash

    SciTech Connect

    Poran, C.J. ); Ahtchi-Ali, F. )

    1989-08-01

    Since the late 1950s solid waste incinerators have become widely used in the United States. The incineration of solid waste produces large quantities of bottom and fly ash, which has been disposed of primarily by landfilling. However, as landfills become undesirable other disposal methods are being sought. An experimental research program is conducted to determine engineering properties of solid waste incinerator fly ash (SWIF) in order to evaluate the feasibility of using the material for compacted fill and road and subbase construction. Moisture-density relationship, permeability, shear strength, and California bearing ratio (CBR) are investigated. The effects of densification on these engineering properties are also examined. In addition, the effectiveness of cement and lime stabilization is investigated using two common mix ratios. Test results of stabilized mixes are compared to the unstabilized material. Cement stabilization is found to be very effective in reducing permeability, and increasing shear strength and CBR values of the material. The results indicate that SWIF with cement stabilization may be used effectively for compacted fill and road subbase construction. Finally, some environmental aspects related to these applications are examined.

  2. Biologic effects of oil fly ash.

    PubMed Central

    Ghio, Andrew J; Silbajoris, Robert; Carson, Johnny L; Samet, James M

    2002-01-01

    Epidemiologic studies have demonstrated increased human morbidity and mortality with elevations in the concentration of ambient air particulate matter (PM). Fugitive fly ash from the combustion of oil and residual fuel oil significantly contributes to the ambient air particle burden. Residual oil fly ash (ROFA) is remarkable in the capacity to provoke injury in experimental systems. The unique composition of this emission source particle makes it particularly useful as a surrogate for ambient air PM in studies of biologic effects testing the hypothesis that metals mediate the biologic effects of air pollution particles. A majority of the in vitro and animal model investigations support the postulate that transition metals present in ROFA (especially vanadium) participate in Fenton-like chemical reactions to produce reactive oxygen species. This is associated with tyrosine phosphorylation, nuclear factor kappa B and other transcription factor activation, induction of inflammatory mediator expression, and inflammatory lung injury. It is also evident that vanadium accounts for a significant portion of the biologic activity of ROFA. The extrapolation of this body of investigation on ROFA to the field of ambient air PM is difficult, as particles in numerous environments have such small amounts of vanadium. PMID:11834466

  3. Biologic effects of oil fly ash.

    PubMed

    Ghio, Andrew J; Silbajoris, Robert; Carson, Johnny L; Samet, James M

    2002-02-01

    Epidemiologic studies have demonstrated increased human morbidity and mortality with elevations in the concentration of ambient air particulate matter (PM). Fugitive fly ash from the combustion of oil and residual fuel oil significantly contributes to the ambient air particle burden. Residual oil fly ash (ROFA) is remarkable in the capacity to provoke injury in experimental systems. The unique composition of this emission source particle makes it particularly useful as a surrogate for ambient air PM in studies of biologic effects testing the hypothesis that metals mediate the biologic effects of air pollution particles. A majority of the in vitro and animal model investigations support the postulate that transition metals present in ROFA (especially vanadium) participate in Fenton-like chemical reactions to produce reactive oxygen species. This is associated with tyrosine phosphorylation, nuclear factor kappa B and other transcription factor activation, induction of inflammatory mediator expression, and inflammatory lung injury. It is also evident that vanadium accounts for a significant portion of the biologic activity of ROFA. The extrapolation of this body of investigation on ROFA to the field of ambient air PM is difficult, as particles in numerous environments have such small amounts of vanadium.

  4. Environmental hazard of oil shale combustion fly ash.

    PubMed

    Blinova, Irina; Bityukova, Liidia; Kasemets, Kaja; Ivask, Angela; Käkinen, Aleksandr; Kurvet, Imbi; Bondarenko, Olesja; Kanarbik, Liina; Sihtmäe, Mariliis; Aruoja, Villem; Schvede, Hedi; Kahru, Anne

    2012-08-30

    The combined chemical and ecotoxicological characterization of oil shale combustion fly ash was performed. Ash was sampled from the most distant point of the ash-separation systems of the Balti and Eesti Thermal Power Plants in North-Eastern Estonia. The fly ash proved potentially hazardous for tested aquatic organisms and high alkalinity of the leachates (pH>10) is apparently the key factor determining its toxicity. The leachates were not genotoxic in the Ames assay. Also, the analysis showed that despite long-term intensive oil-shale combustion accompanied by considerable fly ash emissions has not led to significant soil contamination by hazardous trace elements in North-Eastern Estonia. Comparative study of the fly ash originating from the 'new' circulating fluidized bed (CFB) combustion technology and the 'old' pulverized-fired (PF) one showed that CFB fly ash was less toxic than PF fly ash. Thus, complete transfer to the 'new' technology will reduce (i) atmospheric emission of hazardous trace elements and (ii) fly ash toxicity to aquatic organisms as compared with the 'old' technology. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Sorption and chemical transformation of PAHs on coal fly ash

    SciTech Connect

    Mamantov, G.; Wehry, E.L.

    1992-01-01

    The objective of this research is to characterize the interactions of coal fly ash with polycyclic aromatic hydrocarbons (PAHs) and their derivatives, and to understand the influence of the surface properties of coal ash (and other atmospheric particles) on the chemical transformations of polycyclic aromatic compounds. During the past year the following specific aspects of this broad problem area have been investigated: (a) Fractionation of heterogeneous coal fly ash samples into different particle types varying in size and chemical composition (carbonaceous, mineral-magnetic, and mineral nonmagnetic); (b) The use of gas-solid chromatography to measure heats of sorption of PAHS, and PAH derivatives, on coal fly ashes and ash fractions. (c) Identification of the major photoproduct(s) of the photodecomposition of one PAH (benz[a]anthracene) sorbed on model adsorbents; (d) Estimation of fractal dimensions'' of coal fly ash particles by use of specific surface area measurements, with an ultimate objective of using these measurements to assess the importance of inner-filter effects'' on the photodecomposition of PAHs sorbed on fly ash particles. (e) The photochemical transformation of a representative nitro-PAH derivative (1-nitropyrene) sorbed on fly ash. (f) Development of techniques for studying the nonphotochemical reactions of hydroxyl radicals (and other atmospheric constituents) with PAHs sorbed on fly ash. Progress achieved, and problems encountered, in each of these major areas of emphasis is described below.

  6. Fundamental Study of Low-Nox Combustion Fly Ash Utilization

    SciTech Connect

    E. M. Suuberg; I. Kuloats; K. Smith; N. Sabanegh; R. H. Hurt; W. D. Lilly; Y. M. Gao

    1997-11-01

    This study is principally concerned with characterizing the organic part of coal combustion fly ashes. High carbon fly ashes are becoming more common as by-products of low-NOx combustion technology, and there is need to learn more about this fraction of the fly ash. The project team consists of two universities, Brown and Princeton, and an electrical utility, New England Power. A sample suite of over forty fly ashes has been gathered from utilities across the United States, and includes ashes from a coals ranging in rank from bituminous to lignite. The characterizations of these ashes include standard tests (LOI, Foam Index), as well as more detailed characterizations of their surface areas, porosity, extractability and adsorption behavior. The ultimate goal is, by better characterizing the material, to enable broadening the range of applications for coal fly ash re-use beyond the current main market as a pozzolanic agent for concretes. The potential for high carbon-content fly ashes to substitute for activated carbons is receiving particular attention. The work performed to date has already revealed how very different the surfaces of different ashes produced by the same utility can be, with respect to polarity of the residual carbon. This can help explain the large variations in acceptability of these ashes as concrete additives.

  7. FUNDAMENTAL STUDY OF LOW-NOx COMBUSTION FLY ASH UTILIZATION

    SciTech Connect

    ERIC M. SUUBERG; ROBERT H. HURT

    1998-10-19

    This study is principally concerned with characterizing the organic part of coal combustion fly ashes. High carbon fly ashes are becoming more common as by-products of low-NOx combustion technology, and there is need to learn more about this fraction of the fly ash. The project team consists of two universities, Brown and Princeton, and an electrical utility, New England Power. A sample suite of over fifty fly ashes has been gathered from utilities across the United States, and includes ashes from a coals ranging in rank from bituminous to lignite. The characterizations of these ashes include standard tests (LOI, Foam Index), as well as more detailed characterizations of their surface areas, porosity, extractability and adsorption behavior. The ultimate goal is, by better characterizing the material, to enable broadening the range of applications for coal fly ash re-use beyond the current main market as a pozzolanic agent for concretes. The potential for high carbon-content fly ashes to substitute for activated carbons is receiving particular attention. The work performed to date has already revealed how very different the surfaces of different ashes produced by the same utility can be, with respect to polarity of the residual carbon. This can help explain the large variations in acceptability of these ashes as concrete additives.

  8. Fundamental Study of Low NOx Combustion Fly Ash Utilization

    SciTech Connect

    E. M. Suubert; I. Kuloats; K. Smith; N. Sabanegh; R.H. Hurt; W. D. Lilly; Y. M. Gao

    1997-05-01

    This study is principally concerned with characterizing the organic part of coal combustion fly ashes. High carbon fly ashes are becoming more common as by-products of low-NOx combustion technology, and there is need to learn more about this fraction of the fly ash. The project team consists of two universities, Brown and Princeton, and an electrical utility, New England Power. A sample suite of over forty fly ashes has been gathered from utilities across the United States, and includes ashes from a coals ranging in rank from bituminous to lignite. The characterizations of these ashes include standard tests (LOI, Foam Index), as well as more detailed characterizations of their surface areas, porosity, extractability and adsorption behavior. The ultimate goal is, by better characterizing the material, to enable broadening the range of applications for coal fly ash re-use beyond the current main market as a pozzolanic agent for concretes. The potential for high carbon-content fly ashes to substitute for activated carbons is receiving particular attention. The work performed to date has already revealed how very different the surfaces of different ashes produced by the same utility can be, with respect to polarity of the residual carbon. This can help explain the large variations in acceptability of these ashes as concrete additives.

  9. Scale-Up and Demonstration of Fly Ash Ozonation Technology

    SciTech Connect

    Rui Afonso; R. Hurt; I. Kulaots

    2006-03-01

    The disposal of fly ash from the combustion of coal has become increasingly important. When the fly ash does not meet the required specification for the product or market intended, it is necessary to beneficiate it to achieve the desired quality. This project, conducted at PPL's Montour SES, is the first near full-scale ({approx}10 ton/day), demonstration of ash ozonation technology. Bituminous and sub bituminous ashes, including two ash samples that contained activated carbon, were treated during the project. Results from the tests were very promising. The ashes were successfully treated with ozone, yielding concrete-suitable ash quality. Preliminary process cost estimates indicate that capital and operating costs to treat unburned carbon are competitive with other commercial ash beneficiation technologies at a fraction of the cost of lost sales and/or ash disposal costs. This is the final technical report under DOE Cooperative Agreement No.: DE-FC26-03NT41730.

  10. The recycling of the coal fly ash in glass production

    SciTech Connect

    Erol, M.M.; Kucukbayrak, S.; Ersoy-Mericboyu, A.

    2006-09-15

    The recycling of fly ash obtained from the combustion of coal in thermal power plant has been studied. Coal fly ash was vitrified by melting at 1773 K for 5 hours without any additives. The properties of glasses produced from coal fly ash were investigated by means of Differential Thermal Analysis (DTA), X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) techniques. DTA study indicated that there was only one endothermic peak at 1003 K corresponding to the glass transition temperature. XRD analysis showed the amorphous state of the glass sample produced from coal fly ash. SEM investigations revealed that the coal fly ash based glass sample had smooth surface. The mechanical, physical and chemical properties of the glass sample were also determined. Recycling of coal fly ash by using vitrification technique resulted to a glass material that had good mechanical, physical and chemical properties. Toxicity characteristic leaching procedure (TCLP) results showed that the heavy metals of Pb, Cr, Zn and Mn were successfully immobilized into the glass. It can be said that glass sample obtained by the recycling of coal fly ash can be taken as a non-hazardous material. Overall, results indicated that the vitrification technique is an effective way for the stabilization and recycling of coal fly ash.

  11. Contaminant retention characteristics of fly ash-bentonite mixes.

    PubMed

    Deka, Abhijit; Sekharan, Sreedeep

    2017-01-01

    It is important to determine the contaminant retention characteristics of materials when assessing their suitability for use as liners in landfill sites. Sand-bentonite mixtures are commonly used as liners in the construction of landfill sites for industrial and hazardous wastes. Sand is considered to be a passive material with a negligible chemical retention capacity; fly ash, however, offers the additional advantage of adsorbing the heavy metals present in landfill leachates. There have been few studies of the contaminant retention characteristics of fly ash-bentonite mixes. The study reported here determined the contaminant retention characteristics of different fly ashes, bentonite and selected fly ash-bentonite mixes for Pb(2+) using 24 h batch tests. The tests were conducted by varying the initial concentrations of metal ions under uncontrolled pH conditions. The efficiency of the removal of Pb(2+) by the different types of fly ash and fly ash-bentonite mixes was studied. The influence of multiple sources of fly ash on the retention characteristics of fly ash-bentonite mixes was investigated.

  12. Process for the recovery of alumina from fly ash

    DOEpatents

    Murtha, M.J.

    1983-08-09

    An improvement in the lime-sinter process for recovering alumina from pulverized coal fly ash is disclosed. The addition of from 2 to 10 weight percent carbon and sulfur to the fly ash-calcium carbonate mixture increase alumina recovery at lower sintering temperatures.

  13. Multinuclear NMR approach to coal fly ash characterization

    SciTech Connect

    Netzel, D.A.

    1991-09-01

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

  14. Optimizing the use of fly ash in concrete

    SciTech Connect

    Thomas, M.

    2007-07-01

    The optimum amount of fly ash varies not only with the application, but also with composition and proportions of all the materials in the concrete mixture (especially the fly ash), the conditions during placing (especially temperature), construction practices (for example, finishing and curing) and the exposure conditions. This document discusses issues related to using low to very high levels of fly ash in concrete and provides guidance for the use of fly ash without compromising the construction process or the quality of the finished product. The nature of fly ashes including their physical, mineralogical and chemical properties is covered in detail, as well as fly ash variability due to coal composition and plant operating conditions. A discussion on the effects of fly ash characteristics on fresh and hardened concrete properties includes; workability, bleeding, air entrainment, setting time, heat of hydration, compressive strength development, creep, drying shrinkage, abrasion resistance, permeability, resistance to chlorides, alkali-silica reaction (ASR), sulfate resistance, carbonation, and resistance to freezing and thawing and deicer salt scaling. Case studies were selected as examples of some of the more demanding applications of fly ash concrete for ASR mitigation, chloride resistance, and green building.

  15. Structure, properties, and surfactant adsorption behavior of fly ash carbon

    NASA Astrophysics Data System (ADS)

    Kulaots, Indrek

    The objective of this research was to suggest methods by which certain problems associated with use of coal fly ash as a pozzolanic agent in concrete mixtures could be alleviated, guided by a better characterization of fly ash properties. A sample suite of eighty fly ashes was gathered from utilities across the world (mainly US-based) and included ashes from coals ranging in rank from bituminous to lignite. The widely used foam index test is used to characterize ashes with respect to their propensity to adsorb surfactants (called Air Entraining Admixtures or AEAs) used to impart freeze-thaw resistance to concrete. In ash-containing concrete mixtures, AEAs are adsorbed from the polar concrete-water solution onto non-polar unburned carbon surfaces in the ash. The AEA uptake by fly ashes only crudely correlates with the amount of carbon in the fly ash, because carbon surface area, accessibility and polarity all play a role in determining adsorption capacities. Fly ash carbon particle size distribution is also a key factor. Fine carbon particles in fly ash fractions of <106mum are responsible for about 90% of surfactant adsorption capacity. Surfactant adsorption on fly ash carbon is, in the foam index test, a dynamic process. The time of the test (typically <10 minutes) is not long enough to permit penetration of small porosity by the relatively large AEA molecules, and only the most readily available adsorption surface near the geometrical surface of the carbon particles is utilized. The nature of the foam index test was also examined, and it is recommended that a more standardized test procedure based upon pure reagents be adopted for examining the nature of fly ashes. Several possible reagents were identified. Room temperature fly ash ozonation is a powerful technique that allows increasing fly ash surface polarity in a relatively short time and thus is very effective for decreasing the AEA uptake capacity. Depending on the ozone input concentration, sample amount

  16. Characterization of metals released from coal fly ash during dredging at the Kingston ash recovery project.

    PubMed

    Bednar, A J; Averett, D E; Seiter, J M; Lafferty, B; Jones, W T; Hayes, C A; Chappell, M A; Clarke, J U; Steevens, J A

    2013-09-01

    A storage-pond dike failure occurred on December 22, 2008 at the Tennessee Valley Authority Kingston Fossil Plant resulting in the release of over 4million cubic meters (5million cubic yards) of fly ash. Approximately half of the released ash was deposited in the main channel of the Emory River, Tennessee, USA. Remediation efforts of the Emory River focused on hydraulic dredging, as well as mechanical excavation in targeted areas. However, agitation of the submerged fly ash during hydraulic dredging introduces river water into the fly ash material, which could promote dissolution and desorption of metals from the solid fly ash material. Furthermore, aeration of the dredge slurry could alter the redox state of metals in the fly ash material and thereby change their sorption, mobility, and toxicity properties. The research presented here focuses on the concentrations and speciation of metals during the fly ash recovery from the Emory River. Our results indicate that arsenite [As(III)] released from the fly ash material during dredging was slowly oxidized to arsenate [As(V)] in the slurry recovery system with subsequent removal through precipitation or sorption reactions with suspended fly ash material. Concentrations of other dissolved metals, including iron and manganese, also generally decreased in the ash recovery system prior to water discharge back to the river. Published by Elsevier Ltd.

  17. Optical properties of fly ash. Volume 1, Final report

    SciTech Connect

    Self, S.A.

    1994-12-01

    Research performed under this contract was divided into four tasks under the following headings: Task 1, Characterization of fly ash; Task 2, Measurements of the optical constants of slags; Task 3, Calculations of the radiant properties of fly ash dispersions; and Task 4, Measurements of the radiant properties of fly ash dispersions. Tasks 1 and 4 constituted the Ph.D. research topic of Sarbajit Ghosal, while Tasks 2 and 3 constituted the Ph.D. research topic of Jon Ebert. Together their doctoral dissertations give a complete account of the work performed. This final report, issued in two volumes consists of an executive summary of the whole program followed by the dissertation of Ghosal. Volume 1 contains the dissertation of Ghosal which covers the characterization of fly ash and the measurements of the radiant properties of fly ash dispersions. A list of publications and conference presentations resulting from the work is also included.

  18. Extraction of vanadium from athabasca tar sands fly ash

    NASA Astrophysics Data System (ADS)

    Gomez-Bueno, C. O.; Spink, D. R.; Rempel, G. L.

    1981-06-01

    The production of refinery grade oil from the Alberta tar sands deposits as currently practiced by Suncor (formally Great Canadian Oil Sands Ltd.—GCOS) generates a substantial amount of petroleum coke fly ash which contains appreciable amounts of valuable metals such as vanadium, nickel and titanium. Although the recovery of vanadium from petroleum ash is a well established commercial practice, it is shown in the present work that such processes are not suitable for recovery of vanadium from the GCOS fly ash. The fact that the GCOS fly ash behaves so differently when compared to other petroleum fly ash is attributed to its high silicon and aluminum contents which tie up the metal values in a silica-alumina matrix. Results of experiments carried out in this investigation indicate that such matrices can be broken down by application of a sodium chloride/water roast of the carbon-free fly ash. Based on results from a series of preliminary studies, a detailed investigation was undertaken in order to define optimum conditions for a vanadium extraction process. The process developed involves a high temperature (875 to 950 °C) roasting of the fly ash in the presence of sodium chloride and water vapor carried out in a rotary screw kiln, followed by dilute sodium hydroxide atmosphereic leaching (98 °C) to solublize about 85 pet of the vanadium originally present in the fly ash. It was found that the salt roasting operation, besides enhancing vanadium recovery, also inhibits silicon dissolution during the subsequent leaching step. The salt roasting treatment is found to improve vanadium recovery significantly when the fly ash is fully oxidized. This is easily achieved by burning off the carbon present in the “as received” fly ash under excess air. The basic leaching used in the new process selectively dissolves vanadium from the roasted ash, leaving nickel and titanium untouched.

  19. Vitrification of municipal solid waste incineration fly ash using biomass ash as additives.

    PubMed

    Alhadj-Mallah, Moussa-Mallaye; Huang, Qunxing; Cai, Xu; Chi, Yong; Yan, JianHua

    2015-01-01

    Thermal melting is an energy-costing solution for stabilizing toxic fly ash discharged from the air pollution control system in the municipal solid waste incineration (MSWI) plant. In this paper, two different types of biomass ashes are used as additives to co-melt with the MSWI fly ash for reducing the melting temperature and energy cost. The effects of biomass ashes on the MSWI fly ash melting characteristics are investigated. A new mathematical model has been proposed to estimate the melting heat reduction based on the mass ratios of major ash components and measured melting temperature. Experimental and calculation results show that the melting temperatures for samples mixed with biomass ash are lower than those of the original MSWI fly ash and when the mass ratio of wood ash reaches 50%, the deformation temperature (DT), the softening, hemisphere temperature (HT) and fluid temperature (FT) are, respectively, reduced by 189°C, 207°C, 229°C, and 247°C. The melting heat of mixed ash samples ranges between 1650 and 2650 kJ/kg. When 50% wood ash is mixed, the melting heat is reduced by more than 700 kJ/kg for the samples studied in this paper. Therefore, for the vitrification treatment of the fly ash from MSW or other waste incineration plants, wood ash is a potential fluxing assistant.

  20. Vegetation establishment on soil-amended weathered fly ash

    SciTech Connect

    Semalulu, O.; Barnhisel, R.I.; Witt, S.

    1998-12-31

    A field study was conducted with the following objectives in mind: (1) to study the effect of soil addition to weathered fly ash on the establishment and survival of different grasses and legumes, (2) to identify suitable grasses and/or legume species for vegetation of fly ash, (3) to study the fertilizer N and P requirements for successful vegetation establishment on fly ash and ash-soil mixtures, (4) to examine the nutrient composition of the plant species tested, and (5) to study the plant availability of P from fly ash and ash-soil mixtures. Three rooting media were used: weathered fly ash, and 33% or 50% soil blended with the ash. Four experiments were established on each of these media to evaluate warm season grasses in pure stands, warm season grasses inter-seeded with legumes, cool season grasses, and cool season grasses inter-seeded with legumes. Soil used in this study was more acidic than the fly ash. Only the results from characterization of the rooting media, ground cover, and yield will be presented here.

  1. Fly ash in landfill top covers - a review.

    PubMed

    Brännvall, E; Kumpiene, J

    2016-01-01

    Increase of energy recovery from municipal solid waste by incineration results in the increased amounts of incineration residues, such as fly ash, that have to be taken care of. Material properties should define whether fly ash is a waste or a viable resource to be used for various applications. Here, two areas of potential fly ash application are reviewed: the use of fly ash in a landfill top cover either as a liner material or as a soil amendment in vegetation layer. Fly ashes from incineration of three types of fuel are considered: refuse derived fuel (RDF), municipal solid waste incineration (MSWI) and biofuel. Based on the observations, RDF and MSWI fly ash is considered as suitable materials to be used in a landfill top cover liner. Whereas MSWI and biofuel fly ashes based on element availability for plant studies, could be considered suitable for the vegetation layer of the top cover. Responsible application of MSWI ashes is, however, warranted in order to avoid element accumulation in soil and elevation of background values over time.

  2. Sorption and chemical transformation of PAHs on coal fly ash

    SciTech Connect

    Mamantov, G.; Wehry, E.L.

    1991-01-01

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

  3. Microbial detection of mutagenic nitro-organic compounds in filtrates of coal fly ash.

    PubMed

    Wei, C; Raabe, O G; Rosenblatt, L S

    1982-01-01

    The presence of mutagenic nitro-organic compounds on coal fly ash was indicated by the greatly reduced microbial mutagenicity of the ash filtrates with nitroreductase-deficient strains of Salmonella typhimurium compared to their corresponding parental strains. Addition of the liver S-9 microsomal enzyme preparation significantly increased the mutagenic activities of the ash extracts. Extracts of fly ash mutagens were prepared with horse serum, dimethyl sulfoxide, or azeotropic benzene/methanol mixture. The data were normalized to net revertants per 10(8) Salmonella typhimurium cells per milligram of ash used. This normalization procedure is essential for interpretation of comparative results. Both four-way and three-way analyses of variance were used to simultaneously evaluate the differences between solvent extracts, fly ash mutagen, S-9 activation, and nitroreductase-deficient strains and their parental strains. Of the three extraction systems tested, benzene/methanol azeotropic mixture was generally found to have the highest extraction power, and horse serum was the lowest. The results show that overall 87.5% (+/- 1.8 SE) of the mutagenic activity of the fly ash was associated with nitro-organic compounds.

  4. Fluidization characteristics of power-plant fly ashes and fly ash-charcoal mixtures. [MS Thesis; 40 references

    SciTech Connect

    Nguyen, C.T.

    1980-03-01

    As a part of the continuing research on aluminum recovery from fly ash by HiChlor process, a plexiglass fluidization column system was constructed for measurement of fluidization parameters for power-plant fly ashes and fly ash-charcoal mixtures. Several bituminous and subbituminous coal fly ashes were tested and large differences in fluidization characteristics were observed. Fly ashes which were mechanically collected fluidized uniformly at low gas flow rates. Most fly ashes which were electrostatically precipitated exhibited channeling tendency and did not fluidize uniformly. Fluidization characteristics of electrostatically collected ashes improve when the finely divided charcoal powder is added to the mixture. The fluidization of the mixture was aided initially by a mechanical stirrer. Once the fluidization had succeeded, the beds were ready to fluidize without the assistance of a mechanical action. Smooth fluidization and large bed expansion were usually observed. The effects of charcoal size and aspect ratio on fluidization characteristics of the mixtures were also investigated. Fluidization characteristics of a fly ash-coal mixture were tested. The mixture fluidized only after being oven-dried for a few days.

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

    PubMed Central

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

    1983-01-01

    Studies were performed to compare the physical and chemical characteristics and the in vitro macrophage cytotoxicity of oil and coal fly ash. Sampling methodology was developed to collect size-fractionated particulate matter from the smokestack of either a coal-fired or an oil-fired power plant. Morphological studies demonstrated particle heterogeneity, although most coal fly ash particles appeared to be spherical. Oil fly ash contained two major morphologies; nonopaque amorphous particles and opaque amorphous particles. Elemental analysis indicates that the coal ash is predominantly composed of aluminosilicate particles, while the oil ash is predominantly inorganic sulfates and carbonaceous particles. In vitro macrophage assays demonstrate that the finest coal fly ash particles are the most cytotoxic; the cytotoxicity is significantly less than that of alpha-quartz, the positive control particle. In contrast, the oil fly ash particles are more cytotoxic than quartz. The cytotoxicity of oil fly ash is due to soluble components, possibly vanadium salts. Images FIGURE 2. A FIGURE 2. B FIGURE 2. C FIGURE 2. D PMID:6641653

  6. Development of Classified Fly Ash as a Pozzolanic Material

    NASA Astrophysics Data System (ADS)

    Rukzon, Sumrerng; Chindaprasirt, Prinya

    This research studies the potential for using classified fly ash from Mae Moh power plant in Thailand as a pozzolanic material. Three different fly ash finenesses viz., coarse Original Fly Ash (OFA), Medium Fly Ash (MFA) and Fine Fly Ash (FFA) were used for the study. Ordinary Portland Cement (OPC) was partially replaced with fly ash at 20 and 40% by weight of binder. The water to binder ratio was kept constant at 0.5 and the flow of mortar was maintained at 110±5% with the aid of superplasticizer (SP). Compressive strength, carbonation depth and porosity test of mortars were determined. FFA has a high potential to be used as a good pozzolanic material. The use of FFA produces mortars with good strength and low porosity. The resistance to carbonation of mortar improves with partial replacement of FFA in comparison with the normal coarse fly ash. The use of FFA results in a strong and dense mortar which is due to better dispersion and filling effect as well as an increase in the pozzolanic reaction.

  7. The use of coal fly ash for soil stabilization

    SciTech Connect

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

    1991-12-01

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

  8. Dewatering to stabilize fly ash disposal ponds. Final report

    SciTech Connect

    Delaney, B.T.; Cluen, G.J.; Floess, C.

    1985-05-01

    The required removal of an inactive fly ash pond at the Seward Generating Station posed three related problems to Pennsylvania Electric Company. The saturated, unstable fly ash was difficult to excavate, to transport and to place on the disposal pile at slopes steep enough to be contained within the limited available storage area. This report describes: the performance of a limited field testing using a vacuum wellpoint dewatering system; the extrapolation of the test data into an overall dewatering scheme; the testing and monitoring performed on the fly ash and dewatering system during ash removal; and the recommended procedures to be used for applying the methods described to other fly ash ponds. The wellpoint system utilized at this site was capable of improving the condition of the fly ash to the extent that excavation of the ash could easily be performed with a tire mounted front end loader operating from the natural clay bottom of the pond. Of the initial twelve-foot average thickness of ash, the residual unstable material after dewatering was less than one foot thick. Hauling and disposal problems were also improved since the ash would no longer flow when being bumped. 21 refs., 56 figs., 9 tabs.

  9. Leaching for recovery of copper from municipal solid waste incineration fly ash: influence of ash properties and metal speciation.

    PubMed

    Lassesson, Henric; Fedje, Karin Karlfeldt; Steenari, Britt-Marie

    2014-08-01

    Recovery of metals occurring in significant amounts in municipal solid waste incineration fly ash, such as copper, could offer several advantages: a decreased amount of potentially mobile metal compounds going to landfill, saving of natural resources and a monetary value. A combination of leaching and solvent extraction may constitute a feasible recovery path for metals from municipal solid waste incineration fly ash. However, it has been shown that the initial dissolution and leaching is a limiting step in such a recovery process. The work described in this article was focused on elucidating physical and chemical differences between two ash samples with the aim of explaining the differences in copper release from these samples in two leaching methods. The results showed that the chemical speciation is an important factor affecting the release of copper. The occurrence of copper as phosphate or silicate will hinder leaching, while sulphate and chloride will facilitate leaching.

  10. Investigation on Leaching Behaviour of Fly Ash and Bottom Ash Replacement in Self-Compacting Concrete

    NASA Astrophysics Data System (ADS)

    Kadir, Aeslina Abdul; Ikhmal Haqeem Hassan, Mohd; Bakri Abdullah, Mohd Mustafa Al

    2016-06-01

    Fly ash and bottom ash are some of the waste generated by coal-fired power plants, which contains large quantities of toxic and heavy metals. In recent years, many researchers have been interested in studying on the properties of self-compacting concrete incorporated with fly ash and bottom ash but there was very limited research from the combination of fly ash and bottom ash towards the environmental needs. Therefore, this research was focused on investigating the leachability of heavy metals of SCC incorporated with fly ash and bottom ash by using Toxicity Characteristic Leaching Procedure, Synthetic Precipitation Leaching Procedure and Static Leaching Test. The samples obtained from the coal-fired power plant located at Peninsula, Malaysia. In this study, the potential heavy metals leached out from SCC that is produced with fly ash as a replacement for Ordinary Portland Cement and bottom ash as a substitute for sand with the ratios from 10% to 30% respectively were designated and cast. There are eight heavy metals of concern such as As, Cr, Pb, Zn, Cu, Ni, Mn and Fe. The results indicated that most of the heavy metals leached below the permissible limits from the United States Environmental Protection Agency and World Health Organization limit for drinking water. As a conclusion, the minimum leaching of the heavy metals from the incorporation of fly ash and bottom ash in self-compacting concrete was found in 20% of fly ash and 20% of bottom ash replacement. The results also indicate that this incorporation could minimize the potential of environmental problems.

  11. The leaching characteristics of selenium from coal fly ashes

    SciTech Connect

    Wang, T.; Wang, J.; Burken, J.G.; Ban, H.; Ladwig, K.

    2007-11-15

    The leaching characteristics of selenium from several bituminous and subbituminous coal fly ashes under different pH conditions were investigated using batch methods. Results indicated that pH had a significant effect on selenium leaching from bituminous coal ash. The minimum selenium leaching occurred in the pH range between 3 and 4, while the maximum selenium leaching occurred at pH 12. The release of selenium from subbituminous coal ashes was very low for the entire experimental pH range, possibly due to the high content of calcium which can form hydration or precipitation products as a sink for selenium. The adsorption results for different selenium species indicated that Se(VI) was hardly adsorbable on either bituminous coal ashes or subbitumminous coal ashes at any pH. However, Se(I) was highly adsorbed by bituminous coal ashes under acidic pH conditions and was mostly removed by subbitumminous coal ashes across the entire pH range. This result suggests that the majority of selenium released from the tested fly ashes was Se(IV). A speciation-based model was developed to simulate the adsorption of Se(IV) on bituminous coal fly ash, and the pH-independent adsorption constants of HSeO{sup 3-} and SeO{sub 3}{sup 2-} were determined. The modeling approach is useful for understanding and predicting the release process of selenium from fly ash.

  12. Supercritical fluid process for removal of polychlorodibenzodioxin and dibenzofuran from fly ash

    SciTech Connect

    Gabarra, P.; Cogollo, A.; Recasens, F.; Fernandez-Escobar, I.; Abad, E.; Bayona, J.M.

    1999-05-01

    A process is proposed for the decontamination of fly ash from an urban solid-waste incineration facility (USWI), where the target contaminants are polychlorodibenzodioxins (PCDDs) and dibenzofurans (PCDFs), a class of highly toxic tricyclopolychlorinated organics. In general, the ash waste requires inertization and disposal into a controlled landfill. Here, the authors propose an inertization process based on the reduction of the PCDDs and PCDFs content before dumping. Inertization is brought about by extraction with a solvent consisting of supercritical carbon dioxide modified with a co-solvent (10% toluene). The plant would run in semibatch mode, with continuous flow of fluid through a packed bed of fly ash. Then, carbon dioxide and the co-solvent would be separated and recycled. Favorable extraction conditions were found in the laboratory at 300 bar and 60 C. Under these conditions, the removal efficiency of native PCDDs and PCDFs is around 50% referred to the extraction of the same sample using the EPA method 1613 (Soxhlet extraction with toluene). A technoeconomic appraisal of a treatment facility is presented for a medium sized incineration plant (50,000 ton urban waste yearly) producing 1,500 ton of fly ash/y. The ash production would be inertized in a specially designed supercritical fluid (SCF) extraction unit, located on-site at the incineration facility.

  13. Recovery of iron oxide from coal fly ash

    DOEpatents

    Dobbins, Michael S.; Murtha, Marlyn J.

    1983-05-31

    A high quality iron oxide concentrate, suitable as a feed for blast and electric reduction furnaces is recovered from pulverized coal fly ash. The magnetic portion of the fly ash is separated and treated with a hot strong alkali solution which dissolves most of the silica and alumina in the fly ash, leaving a solid residue and forming a precipitate which is an acid soluble salt of aluminosilicate hydrate. The residue and precipitate are then treated with a strong mineral acid to dissolve the precipitate leaving a solid residue containing at least 90 weight percent iron oxide.

  14. Increasing Class C fly ash reduces alkali silica reactivity

    SciTech Connect

    Hicks, J.K.

    2007-07-01

    Contrary to earlier studies, it has been found that incremental additions of Class C fly ash do reduce alkali silica reactivity (ASR), in highly reactive, high alkali concrete mixes. AST can be further reduced by substituting 5% metakaolin or silica fume for the aggregate in concrete mixes with high (more than 30%) Class C fly ash substitution. The paper reports results of studies using Class C fly ash from the Labadie Station plant in Missouri which typically has between 1.3 and 1.45% available alkalis by ASTM C311. 7 figs.

  15. Effective use of fly ash slurry as fill material.

    PubMed

    Horiuchi, S; Kawaguchi, M; Yasuhara, K

    2000-09-15

    A lot of effort has been put into increasing coal ash utilization; however, 50% of total amount is disposed of on land and in the sea. Several attempts have been reported recently concerning slurried coal fly ash use for civil engineering materials, such as for structural fill and backfill. The authors have studied this issue for more than 15 years and reported its potential for (1) underwater fills, (2) light weight backfills, and (3) light weight structural fills, through both laboratory tests and construction works. This paper is an overview of the results obtained for slurry, focusing on the following. (1) Coal fly ash reclaimed by slurry placement shows lower compressibility, higher ground density, and higher strength than by the other methods. This higher strength increases stability against liquefaction during earthquake. (2) Higher stability of the fly ash ground formed by slurry placement is caused by higher density and its self-hardening property. (3) Stability of fly ash reclaimed ground can be increased by increasing density and also by strength enhancement by cement addition. (4) Technical data obtained through a man-made island construction project shows the advantages of fly ash slurry in terms of mechanical properties such as higher stability against sliding failure, sufficient ground strength, and also in terms of cost saving. (5) Concentration in leachates from the placed slurry is lower than the Japanese environmental law. (6) In order to enlarge the fly ash slurry application toward a lightweight fill, mixtures of air foam, cement and fly ash were examined. Test results shows sufficient durability of this material against creep failure. This material was then used as lightweight structural fill around a high-rise building, and showed sufficient quality. From the above data, it can be concluded that coal fly ash slurry can be effectively utilized in civil engineering projects.

  16. Fly ash facts for highway engineers. Fly ash use in: Concrete base flowable fill structural fill grout paving. Technical report

    SciTech Connect

    1995-08-01

    Coal fly ash is a coal combustion byproduct (CCB) that has numerous applications as a engineering material; the annual production of CCBs is nearly 82 million metric tons (90 million tons). Since the first edition of Fly Ash Facts for Highway Engineers in 1986, substantial information has been accumulated regarding the use of fly ash. The purpose of this document is to provide technical information about engineering applications to potential users of CCBs and to advance the use of CCBs in ways that are technically sound, commercially competitive, and environmentally safe.

  17. Utilization of CFB fly ash for construction applications

    SciTech Connect

    Conn, R.E.; Sellakumar, K.; Bland, A.E.

    1999-07-01

    Disposal in landfills has been the most common means of handling ash in circulating fluidized bed (CFB) boiler power plants. Recently, larger CFB boilers with generating capacities up to 300 MWe are currently being planned, resulting in increased volumes and disposal cost of ash by-product. Studies have shown that CFB ashes do not pose environmental concerns that should significantly limit their potential utilization. Many uses of CFB ash are being investigated by Foster Wheeler, which can provide more cost-effective ash management. Construction applications have been identified as one of the major uses for CFB ashes. Typically, CFB ash cannot be used as a cement replacement in concrete due to its unacceptably high sulfur content. However, CFB ashes can be used for other construction applications that require less stringent specifications including soil stabilization, road base, structural fill, and synthetic aggregate. In this study, potential construction applications were identified for fly ashes from several CFB boilers firing diverse fuels such as petroleum coke, refuse derived fuel (RDF) and coal. The compressive strength of hydrated fly ashes was measured in order to screen their potential for use in various construction applications. Based on the results of this work, the effects of both ash chemistry and carbon content on utilization potential were ascertained. Actual beneficial uses of ashes evaluated in this study are also discussed.

  18. Optical properties of fly ash. Volume 2, Final report

    SciTech Connect

    Self, S.A.

    1994-12-01

    Research performed under this contract was divided into four tasks under the following headings: Task 1, Characterization of fly ash; Task 2, Measurements of the optical constants of slags; Task 3, Calculations of the radiant properties of fly ash dispersions; and Task 4, Measurements of the radiant properties of fly ash dispersions. Tasks 1 and 4 constituted the Ph.D. research topic of Sarbajit Ghosal, while Tasks 2 and 3 constituted the Ph.D. research topic of Jon Ebert. Together their doctoral dissertations give a complete account of the work performed. This final report, issued in two volumes consists of an executive summary of the whole program followed by the dissertation of Ghosal and Ebert. Volume 2 contains the dissertation of Ebert which covers the measurements of the optical constants of slags, and calculations of the radiant properties of fly ash dispersions. A list of publications and conference presentations resulting from the work is also included.

  19. Fly ash based zeolitic pigments for application in anticorrosive paints

    SciTech Connect

    Shaw, Ruchi Tiwari, Sangeeta

    2016-04-13

    The purpose of this work is to evaluate the utilization of waste fly ash in anticorrosive paints. Zeolite NaY was synthesized from waste fly ash and subsequently modified by exchanging its nominal cation Na{sup +} with Mg{sup 2+} and Ca{sup 2+} ions. The metal ion exchanged zeolite was then used as anticorrosive zeolitic pigments in paints. The prepared zeolite NaY was characterized using X-Ray diffraction technique and Scanning electron microscopy. The size, shape and density of the prepared fly ash based pigments were determined by various techniques. The paints were prepared by using fly ash based zeolitic pigments in epoxy resin and the percentages of pigments used in paints were 2% and 5%. These paints were applied to the mild steel panels and the anticorrosive properties of the pigments were assessed by the electrochemical spectroscopy technique (EIS).

  20. [The composition of PAHs in fly ash in Beijing].

    PubMed

    Huang, C; Xu, W; Zhao, G; Zhong, J; Jiang, K

    2001-07-01

    The composition of polycyclic aromatic hydrocarbons (PAHs) in fly ash samples which were gathered from manufacturing district of Shijingshan district and residential quarters of Haidian district were analyzed using HPLC/MS technique. The differences of the contents of PAHs in fly ash samples from manufacturing district and residential quarters were compared. The changes of the contents of PAHs of different seasons were discussed. In this study 135 PAHs including 55 large PAHs whose molecular weights are greater than 300u were detected in fly ash sample from manufacturing district. HPLC/MS offset the deficiency of GC/MS which can not determine large PAHs directly and can reflect the distribution of PAHs in fly ash more roundly.

  1. Compressive strength of concrete and mortar containing fly ash

    DOEpatents

    Liskowitz, J.W.; Wecharatana, M.; Jaturapitakkul, C.; Cerkanowicz, A.E.

    1998-12-29

    The present invention relates to concrete, mortar and other hardenable mixtures comprising cement and fly ash for use in construction. The invention includes a method for predicting the compressive strength of such a hardenable mixture, which is very important for planning a project. The invention also relates to hardenable mixtures comprising cement and fly ash which can achieve greater compressive strength than hardenable mixtures containing only concrete over the time period relevant for construction. In a specific embodiment, a formula is provided that accurately predicts compressive strength of concrete containing fly ash out to 180 days. In other specific examples, concrete and mortar containing about 15% to 25% fly ash as a replacement for cement, which are capable of meeting design specification required for building and highway construction, are provided. Such materials can thus significantly reduce construction costs. 33 figs.

  2. Compressive strength of concrete and mortar containing fly ash

    DOEpatents

    Liskowitz, John W.; Wecharatana, Methi; Jaturapitakkul, Chai; Cerkanowicz, deceased, Anthony E.

    1998-01-01

    The present invention relates to concrete, mortar and other hardenable mixtures comprising cement and fly ash for use in construction. The invention includes a method for predicting the compressive strength of such a hardenable mixture, which is very important for planning a project. The invention also relates to hardenable mixtures comprising cement and fly ash which can achieve greater compressive strength than hardenable mixtures containing only concrete over the time period relevant for construction. In a specific embodiment, a formula is provided that accurately predicts compressive strength of concrete containing fly ash out to 180 days. In other specific examples, concrete and mortar containing about 15% to 25% fly ash as a replacement for cement, which are capable of meeting design specification required for building and highway construction, are provided. Such materials can thus significantly reduce construction costs.

  3. Compressive strength of concrete and mortar containing fly ash

    DOEpatents

    Liskowitz, J.W.; Wecharatana, M.; Jaturapitakkul, C.; Cerkanowicz, A.E.

    1997-04-29

    The present invention relates to concrete, mortar and other hardenable mixtures comprising cement and fly ash for use in construction. The invention includes a method for predicting the compressive strength of such a hardenable mixture, which is very important for planning a project. The invention also relates to hardenable mixtures comprising cement and fly ash which can achieve greater compressive strength than hardenable mixtures containing only concrete over the time period relevant for construction. In a specific embodiment, a formula is provided that accurately predicts compressive strength of concrete containing fly ash out to 180 days. In other specific examples, concrete and mortar containing about 15% to 25% fly ash as a replacement for cement, which are capable of meeting design specifications required for building and highway construction, are provided. Such materials can thus significantly reduce construction costs. 33 figs.

  4. Compressive strength of concrete and mortar containing fly ash

    DOEpatents

    Liskowitz, John W.; Wecharatana, Methi; Jaturapitakkul, Chai; Cerkanowicz, deceased, Anthony E.

    1997-01-01

    The present invention relates to concrete, mortar and other hardenable mixtures comprising cement and fly ash for use in construction. The invention includes a method for predicting the compressive strength of such a hardenable mixture, which is very important for planning a project. The invention also relates to hardenable mixtures comprising cement and fly ash which can achieve greater compressive strength than hardenable mixtures containing only concrete over the time period relevant for construction. In a specific embodiment, a formula is provided that accurately predicts compressive strength of concrete containing fly ash out to 180 days. In other specific examples, concrete and mortar containing about 15% to 25% fly ash as a replacement for cement, which are capable of meeting design specifications required for building and highway construction, are provided. Such materials can thus significantly reduce construction costs.

  5. Fly ash based zeolitic pigments for application in anticorrosive paints

    NASA Astrophysics Data System (ADS)

    Shaw, Ruchi; Tiwari, Sangeeta

    2016-04-01

    The purpose of this work is to evaluate the utilization of waste fly ash in anticorrosive paints. Zeolite NaY was synthesized from waste fly ash and subsequently modified by exchanging its nominal cation Na+ with Mg2+ and Ca2+ ions. The metal ion exchanged zeolite was then used as anticorrosive zeolitic pigments in paints. The prepared zeolite NaY was characterized using X-Ray diffraction technique and Scanning electron microscopy. The size, shape and density of the prepared fly ash based pigments were determined by various techniques. The paints were prepared by using fly ash based zeolitic pigments in epoxy resin and the percentages of pigments used in paints were 2% and 5%. These paints were applied to the mild steel panels and the anticorrosive properties of the pigments were assessed by the electrochemical spectroscopy technique (EIS).

  6. KINETICS OF FLY ASH BENEFICIATION BY CARBON BURNOUT

    SciTech Connect

    Dr. Joseph N.D. Dodoo; Dr. Joseph M. Okoh

    2000-11-01

    Surface area analyses performed on fly ash samples reveal that the surface area is controlled by carbon content. The higher surface areas found in large particles are due to the presence of highly porous carbonaceous particles. Adsorption-desorption isotherms and t-plots of fly ash samples indicate that fly ash is porous. BJH Adsorption/Desorption pore size analysis reveal that pore diameters are independent of sieve size. They appear to be dependent only on the nature of the material which confers porosity. Based on the results of Brown and Dykstra (41) it is reasonable to assume that calculations of reaction rates at temperatures above 550 C were confounded by weight losses from processes other than carbon oxidation and, therefore, are not useful in determination of the temperature dependence of carbon oxidation in fly ash. The results of the present study indicate that temperatures below 550 C should be used for future studies in order to satisfactorily assess the temperature dependence of carbon oxidation in fly ash. Furthermore, it is also advisable that percent carbon determinations be performed on fly ash samples after the oxidation reactions to determine whether all carbon present in fly ash is oxidized. This will ensure that reaction rates are representative of the complete oxidation of carbon. An inverse relationship was determined between reaction rates and oxygen concentration for this study. As discussed, this may be due to volatilization of volatiles from fly ash and ease of transport of products away from the reaction sites by the action of the vacuum applied to the samples. A more accurate determination of oxygen dependence of carbon oxidation can be accomplished by the use of specialty gases containing different concentrations of oxygen which could eliminate the need to apply vacuum to the samples.

  7. Properties and Leachability of Self-Compacting Concrete Incorporated with Fly Ash and Bottom Ash

    NASA Astrophysics Data System (ADS)

    Kadir, Aeslina Abdul; Ikhmal Haqeem Hassan, Mohd; Jamaluddin, Norwati; Bakri Abdullah, Mohd Mustafa Al

    2016-06-01

    The process of combustion in coal-fired power plant generates ashes, namely fly ash and bottom ash. Besides, coal ash produced from coal combustion contains heavy metals within their compositions. These metals are toxic to the environment as well as to human health. Fortunately, treatment methods are available for these ashes, and the use of fly ash and bottom ash in the concrete mix is one of the few. Therefore, an experimental program was carried out to study the properties and determine the leachability of selfcompacting concrete incorporated with fly ash and bottom ash. For experimental study, self-compacting concrete was produced with fly ash as a replacement for Ordinary Portland Cement and bottom ash as a replacement for sand with the ratios of 10%, 20%, and 30% respectively. The fresh properties tests conducted were slump flow, t500, sieve segregation and J-ring. Meanwhile for the hardened properties, density, compressive strength and water absorption test were performed. The samples were then crushed to be extracted using Toxicity Characteristic Leaching Procedure and heavy metals content within the samples were identified accordingly using Atomic Absorption Spectrometry. The results demonstrated that both fresh and hardened properties were qualified to categorize as self-compacting concrete. Improvements in compressive strength were observed, and densities for all the samples were identified as a normal weight concrete with ranges between 2000 kg/m3 to 2600 kg/m3. Other than that, it was found that incorporation up to 30% of the ashes was safe as the leached heavy metals concentration did not exceed the regulatory levels, except for arsenic. In conclusion, this study will serve as a reference which suggests that fly ash and bottom ash are widely applicable in concrete technology, and its incorporation in self-compacting concrete constitutes a potential means of adding value to appropriate mix and design.

  8. Mutagenicity and genotoxicity of coal fly ash water leachate

    SciTech Connect

    Chakraborty, R.; Mukherjee, A.

    2009-03-15

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

  9. Recyclability of Concrete Pavement Incorporating High Volume of Fly Ash

    PubMed Central

    Yoshitake, Isamu; Ishida, Takeo; Fukumoto, Sunao

    2015-01-01

    Recyclable concrete pavement was made from fly ash and crushed limestone sand and gravel as aggregates so that the concrete pavement could be recycled to raw materials for cement production. With the aim to use as much fly ash as possible for the sustainable development of society, while achieving adequate strength development, pavement concrete having a cement-replacement ratio of 40% by mass was experimentally investigated, focusing on the strength development at an early age. Limestone powder was added to improve the early strength; flexural strength at two days reached 3.5 MPa, the minimum strength for traffic service in Japan. The matured fly ash concrete made with a cement content of 200 kg/m3 achieved a flexural strength almost equal to that of the control concrete without fly ash. Additionally, Portland cement made from the tested fly ash concrete was tested to confirm recyclability, with the cement quality meeting the Japanese classification of ordinary Portland cement. Limestone-based recyclable fly ash concrete pavement is, thus, a preferred material in terms of sustainability. PMID:28793518

  10. Recyclability of Concrete Pavement Incorporating High Volume of Fly Ash.

    PubMed

    Yoshitake, Isamu; Ishida, Takeo; Fukumoto, Sunao

    2015-08-21

    Recyclable concrete pavement was made from fly ash and crushed limestone sand and gravel as aggregates so that the concrete pavement could be recycled to raw materials for cement production. With the aim to use as much fly ash as possible for the sustainable development of society, while achieving adequate strength development, pavement concrete having a cement-replacement ratio of 40% by mass was experimentally investigated, focusing on the strength development at an early age. Limestone powder was added to improve the early strength; flexural strength at two days reached 3.5 MPa, the minimum strength for traffic service in Japan. The matured fly ash concrete made with a cement content of 200 kg/m3 achieved a flexural strength almost equal to that of the control concrete without fly ash. Additionally, Portland cement made from the tested fly ash concrete was tested to confirm recyclability, with the cement quality meeting the Japanese classification of ordinary Portland cement. Limestone-based recyclable fly ash concrete pavement is, thus, a preferred material in terms of sustainability.

  11. Fly Ash Disposal in Ash Ponds: A Threat to Ground Water Contamination

    NASA Astrophysics Data System (ADS)

    Singh, R. K.; Gupta, N. C.; Guha, B. K.

    2016-09-01

    Ground water contamination due to deposition of fly ash in ash ponds was assessed by simulating the disposal site conditions using batch leaching test with fly ash samples from three thermal power plants. The periodic analysis of leachates was performed for selected elements, Fe, Cu, Ni, Cr, Pb and Cd in three different extraction solutions to determine the maximum amount that can be leached from fly ash. It was observed that at low pH value, maximum metals are released from the surface of the ash into leachate. The average concentration of these elements found in ground water samples from the nearby area of ash ponds shows that almost all the metals except `Cr' are crossing the prescribed limits of drinking water. The concentration of these elements at this level can endanger public health and environment.

  12. Ceramic glass from flying-ash

    SciTech Connect

    Chiang, J.F.; Xu, You-Wu; Chen, Pinzhen

    1996-10-01

    A ceramic glass composition compromises of mainly SiO{sub 2}, Al{sub 2}O{sub 3}, MgO and with small percent of CaO, TiO{sub 2}, B{sub 2}O{sub 3}, Fe{sub 2}O{sub 3}/FeO, K{sub 2}O, Na{sub 2}O, and P{sub 2}O{sub 5} has been produced. A convenient source of raw materials is a mixture of flying-ash from power plant, borax manufacturing plant waste, and titanium pigment waste. The ceramic glass is formed from an intermediate ceramic mixture which is subjected to heat treatment. The solid is annealed at another temperature for several hours, and then is reduced to a lower temperature at a rate of 20-30{degrees}C/hour. The final product, the ceramic glass possesses many useful mechanical and chemical properties, such as high compressive strength, high bending strength, high hardness, high impact resistance, acid and alkaline resistance, etc. The ceramic glass can be used as laboratory counter-top, reaction still, manufacture of fluid transfer tubing, sandpaper/grit, and many other industrial applications.

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

    PubMed

    Bankowski, P; Zou, L; Hodges, R

    2004-10-18

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

  14. Development of methods for analyzing organics in fly ash. Final report

    SciTech Connect

    Griest, W.H.; Tomkins, B.A.; Caton, J.E.

    1986-09-01

    This project developed methodology for analyzing polycyclic aromatic hydrocarbons (PAH) and other organic compounds in airborne fly ash from coal-fired power plants. Stack ash samples were used as surrogates for fly ash in sorptivity studies and development of analytical methods. A major finding of this project was the identification of carbonaceous particles, ranging from uncombusted coal to coal coke, as the species principally responsible for the strong sorptivity of ash for PAH. The carbonaceous particles also influence the distribution of surface area and organic matter in the ash, and may provide a transport mechanism for the emitted organic matter from coal combustion. The total organic content of the carbonaceous particles ranged up to 1.6 mass %. Several procedures for the determination of organic matter on ash were developed and evaluated. These ranged from gas chromatographic (GC) screening procedures featuring derivatized solvent extracts and thermal desorptions to more complex sequential procedures involving semipreparative scale high-performance liquid chromatographic (HPLC) fractionation followed by GC or analytical scale HPLC analysis. A preliminary investigation was conducted on the nature of the 60 to 80% off the organic matter (estimated from gravimetric or total organic carbon measurements) which is unaccounted for using current chromatographic procedures. Size-exclusion chromatography and spectroscopic characterization of solvent extracts indicated the presence of oxygenated species with apparent molecular masses 200 to 1000.

  15. Corrosion Studies of Fly Ash and Fly Ash-Slag Based Geopolymer

    NASA Astrophysics Data System (ADS)

    Zainal, F. F.; Amli, S. F. M.; Hussin, K.; Rahmat, A.; Abdullah, M. M. A. B.

    2017-06-01

    Abstract This paper presents the results of corrosion studies between Fly Ash Geopolymer (FG) paste and Fly Ash-Slag Geopolymer (FSG) paste. Geopolymer was made from aluminosilicate inorganic polymers mixed with the alkaline activator in order to reduce the carbon dioxide (CO2) to the ecosystem. Samples then were cured at 60ºC for 24 hours in the oven. Reinforcement bar is placed at the center of the paste. The samples were examined after 7, 14 and 28 days in terms of Open Circuit Potential (OCP) test, phase analysis and morphology analysis. The potential values regarding OCP test for FSG paste from 7 days until 28 days are 0.464 V, 0.474 V and 0.498 V more positive than FG paste which the potential values are 0.087 V, 0.133 V and 0.206 V respectively. From the Pourbaix diagram, all the potential values for FG paste and FSG paste were located in the same Fe2O3, passivity region. Passive layer which is the oxide form exists in this region to protect the reinforcement bar from corrosion agents. It can be proved from phase analysis results which iron oxide hydroxide (FeOOH), hematite (Fe2O3) and magnetite (Fe3O4) peaks exist. The differences of morphological structures of these pastes were observed by Scanning Electron Microscope (SEM). It shows that FSG paste had good corrosion resistance and low corrosion rate compared to FG paste.

  16. Adsorption of tungsten onto zeolite fly ash produced by hydrothermally treating fly ash in alkaline solution.

    PubMed

    Ogata, Fumihiko; Iwata, Yuka; Kawasaki, Naohito

    2014-01-01

    Fly ash (FA) was hydrothermally treated in an alkaline solution to produce zeolite fly ash (Z-FA). The properties of the FA and Z-FA were investigated. The amounts of tungsten (W) adsorbed onto the FA and Z-FA surfaces were evaluated. Z-FA was produced by hydrothermally treating FA in an alkaline solution. The specific surface area and pore volume of the Z-FA were greater than those of the FA. More W was adsorbed onto the Z-FA surface than onto the FA surface. The adsorption isotherms for W were fitted using both the Freundlich and Langmuir equations. The equilibrium concentrations of W adsorbed onto the FA and Z-FA surfaces were subsequently reached within 20 h. The pseudo-second-order model more accurately described the data than did the pseudo-first-order model. Sodium hydroxide solutions (1-50 mmol/L) were used to easily recover W from Z-FA, indicating that Z-FA was useful for recovering W from aqueous solutions.

  17. Producing a synthetic zeolite from secondary coal fly ash.

    PubMed

    Zhou, Chunyu; Yan, Chunjie; Zhou, Qi; Wang, Hongquan; Luo, Wenjun

    2016-11-01

    Secondary coal fly ash is known as a by-product produced by the extracting alumina industry from high-alumina fly ash, which is always considered to be solid waste. Zeolitization of secondary coal fly ash offers an opportunity to create value-added products from this industrial solid waste. The influence of synthesis parameters on zeolite NaA such as alkalinity, the molar ratio of SiO2/Al2O3, crystallization time and temperature was investigated in this paper. It was found that the types of synthetic zeolites produced were to be highly dependent on the conditions of the crystallization process. Calcium ion exchange capacity and whiteness measurements revealed that the synthesized product meets the standard for being used as detergent, indicating a promising use as a builder in detergent, ion-exchangers or selective adsorbents. Yield of up to a maximum of 1.54 g/g of ash was produced for zeolite NaA from the secondary coal fly ash residue. This result presents a potential use of the secondary coal fly ash to obtain a high value-added product by a cheap and alternative zeolitization procedure.

  18. Fly ash reinforced thermoplastic vulcanizates obtained from waste tire powder.

    PubMed

    Sridhar, V; Xiu, Zhang Zhen; Xu, Deng; Lee, Sung Hyo; Kim, Jin Kuk; Kang, Dong Jin; Bang, Dae-Suk

    2009-03-01

    Novel thermoplastic composites made from two major industrial and consumer wastes, fly ash and waste tire powder, have been developed. The effect of increasing fly ash loadings on performance characteristics such as tensile strength, thermal, dynamic mechanical and magnetic properties has been investigated. The morphology of the blends shows that fly ash particles have more affinity and adhesion towards the rubbery phase when compared to the plastic phase. The fracture surface of the composites shows extensive debonding of fly ash particles. Thermal analysis of the composites shows a progressive increase in activation energy with increase in fly ash loadings. Additionally, morphological studies of the ash residue after 90% thermal degradation shows extensive changes occurring in both the polymer and filler phases. The processing ability of the thermoplastics has been carried out in a Monsanto processability testing machine as a function of shear rate and temperature. Shear thinning behavior, typical of particulate polymer systems, has been observed irrespective of the testing temperatures. Magnetic properties and percolation behavior of the composites have also been evaluated.

  19. Illinois basin coal fly ashes. 1. Chemical characterization and solubility

    USGS Publications Warehouse

    Roy, W.R.; Griffin, R.A.; Dickerson, D.R.; Schuller, R.M.; Martin, S.M.C.

    1984-01-01

    Twelve precipitator-collected fly ash samples (nine derived from high-sulfur Illinois Basin coals and three from Western U.S. coals) were found to contain a variety of paraffins, aryl esters, phenols, and polynuclear aromatic hydrocarbons including phenanthrene, pyrene, and chrysene but all at very low concentrations. Less than 1% of the organic carbon in the samples was extractable into benzene. Solubility studies with a short-term (24-h) extraction procedure and a long-term (20-week) procedure indicate that the inorganic chemical composition of some types of fly ash effluent is time dependent and may be most toxic to aquatic ecosystems when initially mixed with water and pumped to disposal ponds. Some acidic, high-Cd fly ashes would be classified as hazardous wastes if coal ash was included in this waste category by future RCRA revisions. ?? 1984 American Chemical Society.

  20. Lipid peroxidation and oxidative status compared in workers at a bottom ash recovery plant and fly ash treatment plants.

    PubMed

    Liu, Hung-Hsin; Shih, Tung-Sheng; Chen, I-Ju; Chen, Hsiu-Ling

    2008-01-01

    Fly ash and ambient emissions of municipal solid waste incinerators contain polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polycyclic aromatic hydrocarbons (PAHs), other organic compounds, metals, and gases. Hazardous substances such as PCDD/Fs, mercury vapors and other silicates, and the components of bottom ash and fly ash elevate the oxidative damage. We compared oxidative damage in workers exposed to hazardous substances at a bottom ash recovery plant and 3 fly ash treatment plants in Taiwan by measuring their levels of plasma malondialdehyde (MDA) and urine 8-hydroxydeoxyguanosine (8-OH-dG). Significantly higher MDA levels were found in fly ash treatment plant workers (3.20 microM) than in bottom ash plant workers (0.58 microM). There was a significant association between MDA levels in workers and their working environment, especially in the fly ash treatment plants. Levels of 8-OH-dG varied more widely in bottom ash workers than in fly ash workers. The association between occupational exposure and 8-OH-dG levels may be affected by the life style of the workers. Because more dioxins and metals may leach from fly ash than from bottom ash, fly ash treatment plant workers should, as much as possible, avoid exposing themselves to fly ash.

  1. Influence of different sized fractions of a fly ash on workability of mortars

    SciTech Connect

    Mora, E.P.; Paya, J.; Monzo, J. . Departamento de Ingenieria de la Construccion)

    1993-07-01

    The study of fly ash as a replacement to mortar workability using a flow table is presented. Flow table spread (FTS) values were measured and correlations among fly ash replacing percentages, water volumes and granulometric distributions of fly ashes have been established. Linear relationships between FFS values and water volumes were obtained in the 200-225 ml water range (0.5 water/cement+fly ash ratio, 3.0 natural sand/cement + fly ash ratio). An increase of water volume implies greater FTS values. Original fly ash was separated in four fractions with different granulometric distributions. FTS values increase as do specific surface, and FTS values decrease as mean diameter of fly ash increase. For the finest fraction, the lubricant effect was counteracted by water adsorption on fly ash particles surfaces. The shape distribution curves of fly ashes (original and their fractions) has an important influence on workability.

  2. Reactivity of fly ashes in a spray dryer FGD process

    SciTech Connect

    Davis, W.T.; Reed, G.D.

    1983-05-01

    During the period 1981-1982, a study was performed to determine the ability of various fly ashes to retain sulfur dioxide in a pilot plant spray dryer/fabric filter flue gas desulfurization system. This knowledge would provide design engineers with the necessary data to determine whether the fly ash from a particular utility could be used as an effective supplement or substitute for slaked lime in a spray dryer system. The study commenced with the collection of 22 fly ashes from lignite, subbituminous, and bituminous eastern and western coals. The ashes were contacted with the flue gas entering the pilot plant by two different techniques. In the first, the ashes were slurried in water and injected into the spray dryer through a spinning disk atomizer. In the second, the ashes were injected as a dry additive into the flue gas upstream of the spray dryer. Analyses were conducted to determine the ability of each ash to retain sulfur dioxide in the system followed by statistical correlations of the sulfur retention with the physical/chemical properties of each ash. 17 references, 32 figures, 19 tables.

  3. Fly ash: Perspective resource for geo-polymer materials production

    NASA Astrophysics Data System (ADS)

    Kargin, Aleksey; Baev, Vladimir; Mashkin, Nikolay; Uglyanica, Andrey

    2016-01-01

    The present paper presents the information about the chemical and mineralogical composition of the ash and slag and their amounts at the dumps of the thermoelectric plants located in the city of Kemerovo. It is known that about 85% of ash and slag from the thermoelectric plants in Russia are removed by means of the hydraulic sluicing systems and only about 15% - by the systems of pneumatic ash handling. Currently, however, the transition from the "wet" ash removal systems to the "dry" ones is outlined. This process is quite logical since the fly ash has the higher reactivity compared with the hydraulic sluicing ash and therefore it is of the great interest for recycling and use. On the other hand, the recent trend is the increased use of fly ash in the production of geo-polymers due to their availability, workability and the increased life of the final product. The analysis is carried out to check the possibility of using the fly ash from various Kemerovo thermoelectric plants as a raw material for the production of the alkali-activated binder.

  4. Leaching of Mixtures of Biochar and Fly Ash

    SciTech Connect

    Palumbo, Anthony Vito; Porat, Iris; Phillips, Jana Randolph; Amonette, J. E.; Drake, Meghan M; Brown, Steven D; Schadt, Christopher Warren

    2009-01-01

    Increasing atmospheric levels of greenhouse gases, especially CO2, and their effects on global temperature have led to interest in the possibility of carbon storage in terrestrial environments.2, 5, 6 Both the residual char from biomass pyrolysis7-9, 12 (biochar) and fly ash from coal combustion1, 13, 14 have the potential to significantly expand terrestrial sequestration options. Both biochar and fly ash also have potentially beneficial effects on soil properties. Fly ash has been shown to increase porosity, water-holding capacity, pH, conductivity, and dissolved SO42-, CO32-, Cl- and basic cations.10, 11, 16 Adding biochar to soil generally raises pH, increases total nitrogen and total phosphorous, encourages greater root development, improves cation exchange capacity and reduces available aluminum.3, 17 Combinations of these benefits likely lead to the observed increased yields for crops including corn and sugarcane.17 with biochar addition to soil. In addition, it has been found that soils with added biochar emit lower amounts of other greenhouse gases (methane and nitrous oxide) 8, 17 than do unammended soils. Biochar and fly ash amendments may be useful in promoting terrestrial carbon sequestration on currently underutilized and degraded lands. For example, about 1% of the US surface lands consist of previously mined lands or highway rights-of-way.18 Poorly managed lands could count for another 15% of US area. Biochar and fly ash amendments could increase productivity of these lands and increase carbon storage in the soil Previous results showed minimal leaching of organic carbon and metals from a variety of fly ashes.15 Here, we are examining the properties of mixtures of biochar, fly ash, and soil and evaluating leaching of organic carbon and metals from the mixtures.

  5. Influence of fly ash fineness and shape on the porosity and permeability of blended cement pastes

    NASA Astrophysics Data System (ADS)

    Sinsiri, Theerawat; Chindaprasirt, Prinya; Jaturapitakkul, Chai

    2010-12-01

    The effects of the fineness and shape of fly ash on the porosity and air permeability of cement pastes were investigated. Pulverized coal combustion (PCC) fly ash and fluidized bed coal combustion (FBC) fly ash classified into three different finenesses were used. River sand with particle size distribution similar to that of fly ash was also used for comparison. Portland cement was replaced with fly ash and ground sand at the dosages of 0, 20wt%, and 40wt%. A water-to-binder ratio (w/b) of 0.35 was used throughout the experiment. The results show that the porosity and air permeability of the pastes are influenced by the shape, fineness, and replacement level of fly ash. The porosity and air permeability of FBC fly ash pastes are higher than those of PCC fly ash pastes. This is due to the higher irregular shape and surface of FBC fly ash compared to the spherical shape and relatively smooth surface of PCC fly ash. The porosity increases with the increase in fly ash replacement level and decreases with the increase in its fineness. The permeability of PCC fly ash pastes decreases with the increase in replacement level and fineness, while for FBC fly ash, the permeability increases with the increase in replacement level. Decreases in porosity and permeability are due to a combined effect of the packing of fine particles and the reaction of fly ash.

  6. Effect of ash circulation in gasification melting system on concentration and leachability of lead in melting furnace fly ash.

    PubMed

    Okada, Takashi; Suzuki, Masaru

    2013-11-30

    In some gasification-melting plants, generated melting furnace fly ash is returned back to the melting furnace for converting the ash to slag. This study investigated the effect of such ash circulation in the gasification-melting system on the concentration and leachability of lead in the melting furnace fly ash. The ash circulation in the melting process was simulated by a thermodynamic calculation, and an elemental analysis and leaching tests were performed on a melting furnace fly ash sample collected from the gasification-melting plant with the ash circulation. It was found that by the ash circulation in the gasification-melting, lead was highly concentrated in the melting furnace fly ash to the level equal to the fly ash from the ash-melting process. The thermodynamic calculation predicted that the lead volatilization by the chlorination is promoted by the ash circulation resulting in the high lead concentration. In addition, the lead extraction from the melting furnace fly ash into a NaOH solution was also enhanced by the ash circulation, and over 90% of lead in the fly ash was extracted in 5 min when using 0.5 mol l(-1) NaOH solution with L/S ratio of 10 at 100 °C. Based on the results, a combination of the gasification-melting with the ash circulation and the NaOH leaching method is proposed for the high efficient lead recovery.

  7. Hierarchical zeolites from class F coal fly ash

    NASA Astrophysics Data System (ADS)

    Chitta, Pallavi

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

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

    PubMed

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

    2011-08-01

    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.

  9. Comparative study on the characteristics of fly ash and bottom ash geopolymers.

    PubMed

    Chindaprasirt, Prinya; Jaturapitakkul, Chai; Chalee, Wichian; Rattanasak, Ubolluk

    2009-02-01

    This research was conducted to compare geopolymers made from fly ash and ground bottom ash. Sodium hydroxide (NaOH) and sodium silicate (Na(2)SiO(3)) solutions were used as activators. A mass ratio of 1.5 Na(2)SiO(3)/NaOH and three concentrations of NaOH (5, 10, and 15M) were used; the geopolymers were cured at 65 degrees C for 48 h. A Fourier transform infrared spectrometer (FT-IR), differential scanning calorimeter (DSC), and scanning electron microscope (SEM) were used on the geopolymer pastes. Geopolymer mortars were also prepared in order to investigate compressive strength. The results show that both fly ash and bottom ash can be utilized as source materials for the production of geopolymers. The properties of the geopolymers are dependent on source materials and the NaOH concentration. Fly ash is more reactive and produces a higher degree of geopolymerization in comparison with bottom ash. The moderate NaOH concentration of 10 M is found to be suitable and gives fly ash and bottom ash geopolymer mortars with compressive strengths of 35 and 18 MPa.

  10. Comparative study on the characteristics of fly ash and bottom ash geopolymers

    SciTech Connect

    Chindaprasirt, Prinya; Jaturapitakkul, Chai; Chalee, Wichian; Rattanasak, Ubolluk

    2009-02-15

    This research was conducted to compare geopolymers made from fly ash and ground bottom ash. Sodium hydroxide (NaOH) and sodium silicate (Na{sub 2}SiO{sub 3}) solutions were used as activators. A mass ratio of 1.5 Na{sub 2}SiO{sub 3}/NaOH and three concentrations of NaOH (5, 10, and 15 M) were used; the geopolymers were cured at 65 deg. C for 48 h. A Fourier transform infrared spectrometer (FT-IR), differential scanning calorimeter (DSC), and scanning electron microscope (SEM) were used on the geopolymer pastes. Geopolymer mortars were also prepared in order to investigate compressive strength. The results show that both fly ash and bottom ash can be utilized as source materials for the production of geopolymers. The properties of the geopolymers are dependent on source materials and the NaOH concentration. Fly ash is more reactive and produces a higher degree of geopolymerization in comparison with bottom ash. The moderate NaOH concentration of 10 M is found to be suitable and gives fly ash and bottom ash geopolymer mortars with compressive strengths of 35 and 18 MPa.

  11. Phosphate immobilization using an acidic type F fly ash.

    PubMed

    Grubb, D G; Guimaraes, M S; Valencia, R

    2000-09-15

    Batch equilibration experiments using a low calcium ( approximately 1 wt.% as CaO), acidic (pH approximately 4.5) Type F fly ash demonstrated phosphate immobilization on the order of 100% to 75% for 50 and 100 mg P/l solutions, respectively. A loosely compacted column of fly ash similarly removed 10 mg P/l for over 85 pore volumes. While the interactions between phosphate and calcium-rich (Type C) ashes are relatively well understood, insight into the mechanisms of phosphate immobilization in Type F ash necessitated a review of the phosphate chemistry and interactions with acidic geomedia. Phosphate adsorption was subsequently modeled using a constant capacitance model approach (CCM) excluding precipitation reactions. Our CCM predictions of total phosphate immobilization (20%) were substantially less than the results of the batch equilibration experiments and phosphate adsorption predicted by other researchers examining near pure natural and synthetic geomedia due to the compositional heterogeneity of the fly ash. Nevertheless, for the amorphous and crystalline phases studied, the immobilization of phosphate in the Type F fly ash is attributed to the formation of insoluble aluminum and iron phosphates at low to medium values of pH.

  12. Fly ash as a liming material for corn production

    SciTech Connect

    Tarkalson, D.D.; Hergert, G.W.; Stevens, W.B.; McCallister, D.L.; Kackman, S.D.

    2005-05-01

    Fly ash produced as a by-product of subbituminous coal combustion can potentially serve as an alternative liming material without negatively affecting corn (Zea mays L.) production in areas where use of conventional liming materials can be uneconomical due to transportation costs. A study was conducted to determine if fly ash produced from the Nebraska Public Power District Gerald Gentleman Power Station located in Sutherland, NE could be used as an alternative liming material. Combinations of dry fly ash (DFA), wet fly ash (WFA), beet lime (by-product of sugar beet (Beta vulgaris L.) processing) (BL), and agricultural lime (AGL) were applied at rates ranging from 0.43 to 1.62 times the recommended lime rate to plots on four acidic soils (Anselmo fine sandy loam, Hord fine sandy loam, Holdrege sandy loam, and Valentine fine sand). Soil samples were collected to a depth of 0.2 m from plots and analyzed for pH before lime applications and twice periodically after lime application. The Hord and Valentine soils were analyzed for exchangeable Ca, Mg, K, Na,and Al for determination of percent Al saturation on selected treatments and sampling dates. Corn grain yields were determined annually. It is concluded that the fly ash utilized in this study and applied at rates in this study, increases soil pH comparable to agricultural lime and is an appropriate alternative liming material.

  13. Sorbents for CO2 capture from high carbon fly ashes.

    PubMed

    Maroto-Valer, M Mercedes; Lu, Zhe; Zhang, Yinzhi; Tang, Zhong

    2008-11-01

    Fly ashes with high-unburned-carbon content, referred to as fly ash carbons, are an increasing problem for the utility industry, since they cannot be marketed as a cement extender and, therefore, have to be disposed. Previous work has explored the potential development of amine-enriched fly ash carbons for CO2 capture. However, their performance was lower than that of commercially available sorbents, probably because the samples investigated were not activated prior to impregnation and, therefore, had a very low surface area. Accordingly, the work described here focuses on the development of activated fly ash derived sorbents for CO2 capture. The samples were steam activated at 850 degrees C, resulting in a significant increase of the surface area (1075 m2/g). The activated samples were impregnated with different amine compounds, and the resultant samples were tested for CO2 capture at different temperatures. The CO2 adsorption of the parent and activated samples is typical of a physical adsorption process. The impregnation process results in a decrease of the surface areas, indicating a blocking of the porosity. The highest adsorption capacity at 30 and 70 degrees C for the amine impregnated activated carbons was probably due to a combination of physical adsorption inherent from the parent sample and chemical adsorption of the loaded amine groups. The CO2 adsorption capacities for the activated amine impregnated samples are higher than those previously published for fly ash carbons without activation (68.6 vs. 45 mg CO2/g sorbent).

  14. [MSW incineration fly ash melting by DSC-DTA].

    PubMed

    Li, Rundong; Chi, Yong; Li, Shuiqing; Wang, Lei; Yan, Jianhua; Cen, Kefa

    2002-07-01

    Melting characteristics of two kinds of municipal solid waste incineration(MSWI) fly ash were studied in this paper by high temperature differential scanning calorimetry and differential temperature analysis. MSWI fly ash was considered as hazardous waste because it contains heavy metals and dioxins. The experiments were performed in either N2 or O2 atmosphere in temperature range of 20 degrees C-1450 degrees C at various heating rates. Two different MSW incineration fly ashes used in the experiments were collected from our country and France respectively. The process of fly ash melting exhibits two reactions occurring at temperature ranges of about 480 degrees C-670 degrees C and 1136 degrees C-1231 degrees C, respectively. The latent heat of polymorphic transformation and fusion were approximately 20 kJ/kg and 700 kJ/kg, while the total heat required for melting process was about 1800 kJ/kg. The paper also studied effect of CaO to melting. A heat flux thermodynamic model for fly ash melting was put forward and it agrees well with experimental data.

  15. Fly ash design manual for road and site applications

    SciTech Connect

    DiGioia, A.M. Jr.; Brendel, G.F.; McLaren, R.J.; Balsamo, N.J.; Glogowski, P.E.; Kelley, J.M. )

    1992-04-01

    This design manual is the second of two volumes pertaining to the use of fly ash as a construction material in road and site development applications. Volume 1 describes the use of fly ash conditioned with small amounts of water to produce a solid, soil-like material. Volume 2 describes the use of fly ash mixed with sufficient water to create a fluid or semi-fluid material. In most applications, Portland cement is added to the mixture to provide the desired level of strength. In some applications, aggregate filler is also added to the mixture to improve the durability of the mix. The flowable nature of these materials determines the manner in which they are handled, placed, and used in construction. The following uses are discussed: Slurry Backfills; Grouting; and Hydraulic Fills. Miscellaneous uses are also discussed, including the use of fly ash in high fly ash content concrete, unsintered synthetic aggregate, and slurry walls. Also included are three appendices containing additional information of interest to the designer: Mix Design; Laboratory Test Procedures; and a Bibliography.

  16. Chloride chemical form in various types of fly ash.

    PubMed

    Zhu, Fenfen; Takaoka, Masaki; Shiota, Kenji; Oshita, Kazuyuki; Kitajima, Yoshinori

    2008-06-01

    Chloride content is a critical problem for the reuse of fly ash as a raw material in cement, and the method used by recyclers to reduce the fly ash chloride content depends on the chemical form of the chlorides. However, limited information is available on the quantitative distribution of chlorides and the identity of some chlorides such as Friedel's salt. We examined chloride forms and percentages using X-ray absorption near edge structure and X-ray diffraction analyses, as well as corresponding washing experiments. Approximately 15% of the chlorine in raw fly ash was estimated to be in the form of NaCI, 10% in KCl, 50% in CaCl2, and the remainder in the form of Friedel's salt. Fly ash collected in a bag filter with the injection of calcium hydroxide for acid gas removal (CaFA) contained 35% chlorine as NaCl, 11% as KCI, 37% as CaCl2, 13% as Friedel's salt, and the remaining 4% as CaClOH. In fly ash collected in a bag filter with the injection of sodium bicarbonate for acid gas removal (NaFA), approximately 79% of chlorine was in NaCl, 12% was in KCl, and 9% was in Friedel's salt.

  17. Chloride chemical form in various types of fly ash

    SciTech Connect

    Fenfen Zhu; Masaki Takaoka; Kenji Shiota; Kazuyuki Oshita; Yoshinori Kitajima

    2008-06-01

    Chloride content is a critical problem for the reuse of fly ash as a raw material in cement, and the method used by recyclers to reduce the fly ash chloride content depends on the chemical form of the chlorides. However, limited information is available on the quantitative distribution of chlorides and the identity of some chlorides such as Friedel's salt. We examined chloride forms and percentages using X-ray absorption near edge structure and X-ray diffraction analyses, as well as corresponding washing experiments. Approximately 15% of the chlorine in raw fly ash was estimated to be in the form of NaCl, 10% in KCl, 50% in CaCl{sub 2}, and the remainder in the form of Friedel's salt. Fly ash collected in a bag filter with the injection of calcium hydroxide for acid gas removal (CaFA) contained 35% chlorine as NaCl, 11% as KCl, 37% as CaCl{sub 2}, 13% as Friedel's salt, and the remaining 4% as CaClOH. In fly ash collected in a bag filter with the injection of sodium bicarbonate for acid gas removal (NaFA), approximately 79% of chlorine was in NaCl, 12% was in KCl, and 9% was in Friedel's salt. 25 refs., 4 figs., 4 tabs.

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

    PubMed

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

    2016-04-01

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

  19. Cementitious binder from fly ash and other industrial wastes

    SciTech Connect

    Singh, M.; Garg, M.

    1999-03-01

    In this paper, investigations were undertaken to formulate cementitious binder by judicious blending of fly ash with Portland cement as well as by admixing fly ash with calcined phosphogypsum, fluorogypsum, lime sludge, and chemical activators of different finenesses. The effect of addition of calcined clay in these types of binders was studied. Data showed that cementitious binders of high compressive strength and water retentivity can be produced. The strength of masonry mortars increased with the addition of chemical activators. The strength development of binders takes place through formation of ettringite. C-S-H, and C{sub 4}AH{sub 13}. The binders are eminently suitable for partial replacement (up to 25%) of the cement in concrete without any detrimental affect on the strength. The results showed that fly ash can be used in the range from 45% to 70% in formulating these binders along with other industrial wastes to help in mitigating environmental pollution.

  20. Dielectric properties of epoxy resin fly ash composite

    NASA Astrophysics Data System (ADS)

    Pattanaik, A.; Bhuyan, S. K.; Samal, S. K.; Behera, A.; Mishra, S. C.

    2016-02-01

    Epoxy resin is widely used as an insulating material in high voltage applications. Ceramic fillers are always added to the polymer matrix to enhance its mechanical properties. But at the same time, filler materials decreases the electrical properties. So while making the fly ash epoxy composite, it is obvious to detect the effect of fly ash reinforcement on the dielectric nature of the material. In the present research work, fly ash is added to four different weight percentages compositions and post-curing has been done in the atmospheric condition, normal oven and micro oven. Tests were carried out on the developed polymer composite to measure its dielectric permittivity and tan delta value in a frequency range of 1 Hz - 1 MHz. The space charge behaviours were also observed by using the pulse electroacoustic (PEA) technique. The dielectric strength and losses are compared for different conditions.

  1. Coal fly ash: a potential resource for aluminium and titanium

    SciTech Connect

    Frederick, J.R.; Murtha, M.J.; Burnet, G.

    1980-01-01

    Two processes are described which utilize fly ash as a source of metals and by-products. The lime-soda sinter process involves sintering of the fly ash and alkaline oxides at 1100-1300/sup 0/C to break the alumina-silica bonds and form soluble aluminate compounds and insoluble calcium silicates. The aluminates are extracted from the sinter by dissolution in sodium carbonate. The calcium silicate sinter extract shows promise as a raw material for the manufacture of portland cement. The HiChlor process uses high temperature chlorination of fly ash in the presence of a reductant to form volatile metal chlorides of aluminium, titanium, iron, and silicon. The HiChlor process extracts aluminium, titanium, and iron, while the sinter process extracts only aluminium.

  2. Sintered mullite from fly ash and alumina powder mixture

    SciTech Connect

    Sun Junmin; Li Yuqiong

    1997-12-31

    Fly ash generated in coal-fired power plants is produced mainly from the aluminosilicates in coal powder. To utilize fly ash in making refractory products, a study of the synthesis of mullite from fly ash and alumina powder mixture was initiated. A series of sintered products designated M70, M60, M50 was achieved with Al{sub 2}O{sub 3} contents in the mixtures being 70%, 60%, 50%, respectively. Properties of M70 and M60 are comparable to those of commercial mullite. Though the M50 cannot be used as superior refractory material, it has great potential in making ceramic kiln tools to replace the traditional clayey products.

  3. Role of aluminous component of fly ash on the durability of Portland cement-fly ash pastes in marine environment

    SciTech Connect

    Lorenzo, MaP.; Goni, S.; Guerrero, A

    2003-07-01

    The durability, of mixtures of two kinds of Spanish fly ashes from coal combustion (ASTM class F) with 0, 15 and 35% replacement of Portland cement by fly ash, in a simulated marine environment (Na{sub 2}SO{sub 4}+NaCl solution of equivalent concentration to that of sea water: 0.03 and 0.45 M for sulphate and chloride, respectively), has been studied for a period of 90 days. The resistance of the different mixtures to the attack was evaluated by means of the Koch-Steinegger test. The results showed that all the mixtures were resistant, in spite of the great amount of Al{sub 2}O{sub 3} content of the fly ash. The diffusion of SO{sub 4}{sup 2-}, Na{sup +} and Cl{sup -} ions through the pore solution activated the pozzolanic reactivity of the fly ashes causing the corresponding microstructure changes, which were characterized by X-ray diffraction (XRD), mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM). As a result, the flexural strength of the mixtures increased, principally for the fly ash of a lower particle size and 35% of addition.

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

    USGS Publications Warehouse

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

    2011-01-01

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

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

    SciTech Connect

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

    2016-02-08

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

  6. Rheology and Extrusion of Cement-Fly Ashes Pastes

    NASA Astrophysics Data System (ADS)

    Micaelli, F.; Lanos, C.; Levita, G.

    2008-07-01

    The addition of fly ashes in cement pastes is tested to optimize the forming of cement based material by extrusion. Two sizes of fly ashes grains are examinated. The rheology of concentrated suspensions of ashes mixes is studied with a parallel plates rheometer. In stationary flow state, tested suspensions viscosities are satisfactorily described by the Krieger-Dougherty model. An "overlapped grain" suspensions model able to describe the bimodal suspensions behaviour is proposed. For higher values of solid volume fraction, Bingham viscoplastic behaviour is identified. Results showed that the plastic viscosity and plastic yield values present minimal values for the same optimal formulation of bimodal mixes. The rheological study is extended to more concentrated systems using an extruder. Finally it is observed that the addition of 30% vol. of optimized ashes mix determined a significant reduction of required extrusion load.

  7. Factors affecting the shrinkage of fly ash geopolymers

    NASA Astrophysics Data System (ADS)

    Ridtirud, Charoenchai; Chindaprasirt, Prinya; Pimraksa, Kedsarin

    2011-02-01

    The shrinkage of fly ash geopolymers was studied in the present study. Fly ash was used as the source material for making the geopolymers. The effects of the concentration of NaOH, sodium silicate-to-NaOH ratio, liquid-to-ash ratio, curing temperature, and curing time on shrinkage were investigated. The geopolymers were cured at 25, 40, and 60°C, respectively. The results indicate that the shrinkage of geopolymers is strongly dependent on curing temperature and liquid-to-ash ratio. The increase in shrinkage is associated with the low strength development of geopolymers. It is also found that NaOH concentration and sodium silicate-to-NaOH ratio also affect the shrinkage of geopolymers but to a lesser extent.

  8. Water Adsorption Isotherms on Fly Ash from Several Sources.

    PubMed

    Navea, Juan G; Richmond, Emily; Stortini, Talia; Greenspan, Jillian

    2017-10-03

    In this study, horizontal attenuated total reflection (HATR) Fourier-transform infrared (FT-IR) spectroscopy was combined with quartz crystal microbalance (QCM) gravimetry to investigate the adsorption isotherms of water on fly ash, a byproduct of coal combustion in power plants. Because of composition variability with the source region, water uptake was studied at room temperature as a function of relative humidity (RH) on fly ash from several regions: United States, India, The Netherlands, and Germany. The FT-IR spectra show water features growth as a function of RH, with water absorbing on the particle surface in both an ordered (ice-like) and a disordered (liquid-like) structure. The QCM data was modeled using the Brunauer, Emmett, and Teller (BET) adsorption isotherm model. The BET model was found to describe the data well over the entire range of RH, showing that water uptake on fly ash takes place mostly on the surface of the particle, even for poorly combusted samples. In addition, the source region and power-plant efficiency play important roles in the water uptake and ice nucleation (IN) ability of fly ash. The difference in the observed water uptake and IN behavior between the four samples and mullite (3Al2O3·2SiO2), the aluminosilicate main component of fly ash, is attributed to differences in composition and the density of OH binding sites on the surface of each sample. A discussion is presented on the RH required to reach monolayer coverage on each sample as well as a comparison between surface sites of fly ash samples and enthalpies of adsorption of water between the samples and mullite.

  9. Restoration of fly ash dump through biological interventions.

    PubMed

    Juwarkar, Asha A; Jambhulkar, Hemlata P

    2008-04-01

    Field experiment on 10 ha area of fly ash dump was conducted to restore and revegetate it using biological interventions, which involves use of organic amendment, selection of suitable plant species along with specialized nitrogen fixing strains of biofertilizer. The results of the study indicated that amendment with farm yard manure at 50 t/ha improved the physical properties of fly ash such as maximum water holding capacity from 40.0 to 62.42% while porosity improved from 56.78 to 58.45%. The nitrogen content was increased by 4.5 times due to addition of nitrogen fixing strains of Bradyrhizobium and Azotobacter species, while phosphate content was increased by 10.0 times due to addition of VAM, which helps in phosphate immobilization. Due to biofertilizer inoculation different microbial groups such as Rhizobium, Azotobacter and VAM spores, which were practically absent in fly ash improved to 7.1 x 10(7), 9.2 x 10(7) CFU/g and 35 VAM spores/10 g of fly ash, respectively. Inoculation of biofertilizer and application of FYM helped in reducing the toxicity of heavy metals such as cadmium, copper, nickel and lead which were reduced by 25, 46, 48 and 47%, respectively, due to the increased organic matter content in the fly ash which complexes the heavy metals thereby decreasing the toxicity of metals. Amendment of fly ash with FYM and biofertilizer helped in profuse root development showing 15 times higher growth in Dendrocalamus strictus plant as compared to the control. Thus amendment and biofertilizer application provided better supportive material for anchorage and growth of the plant.

  10. Production of inorganic pellet binders from fly-ash. Technical report, March 1--May 31, 1995

    SciTech Connect

    Kawatra, S.K.; Eisele, T.C.

    1995-12-31

    Fly-ash is produced by all coal-fired utilities, and it must be removed from the plant exhaust gases, collected, and disposed of. While much work has been done in the past to utilize fly-ash rather than disposing of it, we nevertheless do not find widespread examples of successful industrial utilization. This is because past work has tended to find uses only for high-quality, easily-utilized fly-ashes, which account for less than 25% of the fly-ash that is produced. The main factor which makes fly-ashes unusable is a high unburned carbon content. In this project, physical separation technologies are being used to remove this carbon, and to convert these unusable fly-ashes into usable products. The main application being studied for the processed fly-ash is as a binder for inorganic materials, such as iron-ore pellets. In the second quarter, additional fly-ash samples were collected from the E. D. Edwards station (Bartonville, IL). Experimentation was begun to study the removal of carbon from these fly-ashes by froth flotation, and make and test pellets that use fly-ash as binder. During the current quarter, flotation experiments were continued on the fly- ashes. Three types of ashes were studied: 1. Ash from the disposal pond (``wet`` ash); 2. Dry fly-ash collected directly from the standard burners (``low-carbon`` ash); 3. Dry fly-ash collected from the low-NOx burners (``high-carbon`` ash). Each of these was chemically analyzed, and conventional flotation experiments were carried out to determine the optimum reagent dosages for carbon removal. Decarbonized ashes were then made from each ash type, in sufficient quantity to be used in pelletization experiments.

  11. Temporal and spatial variations in fly ash quality

    USGS Publications Warehouse

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

    2001-01-01

    Fly ash quality, both as the amount of petrographically distinguishable carbons and in chemistry, varies in both time and space. Temporal variations are a function of a number of variables. Variables can include variations in the coal blend organic petrography, mineralogy, and chemistry; variations in the pulverization of the coal, both as a function of the coal's Hardgrove grindability index and as a function of the maintenance and settings of the pulverizers; and variations in the operating conditions of the boiler, including changes in the pollution control system. Spatial variation, as an instantaneous measure of fly ash characteristics, should not involve changes in the first two sets of variables listed above. Spatial variations are a function of the gas flow within the boiler and ducts, certain flow conditions leading to a tendency for segregation of the less-dense carbons in one portion of the gas stream. Caution must be applied in sampling fly ash. Samples from a single bin, or series of bins, m ay not be representative of the whole fly ash, providing a biased view of the nature of the material. Further, it is generally not possible to be certain about variation until the analysis of the ash is complete. ?? 2001 Elsevier Science B.V. All rights reserved.

  12. Emanation coefficients for Rn in sized coal fly ash.

    PubMed

    Kalkwarf, D R; Jackson, P O; Kutt, J C

    1985-04-01

    Emanation coefficients for 222Rn in sized samples of dry coal fly ash were evaluated as a function of source and particle size using a modification of the "sealed-can, gamma-only" technique. The emanation coefficient is defined as the fraction of Rn atoms that escape the solid particles of a source. Diffusible Rn was separated from nondiffusible Rn by adsorption on charcoal, and each was measured independently by gamma-ray spectrometry of the Rn daughter, 214Bi. Samples of ash from eastern bituminous coal, western bituminous coal and mid-western bituminous coal with aerodynamic equivalent diameters of less than 15 micron were examined, and the measured emanation coefficients ranged from 0.098 down to 0.007. These values were dependent on both the size and source of the fly ash. The emanation coefficients and the specific activities generally decreased monotonically with increasing aerodynamic equivalent diameter. For unfractionated standard fly ash, SRM 1633a, from the U.S. National Bureau of Standards, the emanation coefficient for 222Rn was found to be 0.018. The results suggest that only a small fraction of the Rn in lung-deposited fly ash will be removed by exhalation.

  13. Optimising Ambient Setting Bayer Derived Fly Ash Geopolymers

    PubMed Central

    Jamieson, Evan; Kealley, Catherine S.; van Riessen, Arie; Hart, Robert D.

    2016-01-01

    The Bayer process utilises high concentrations of caustic and elevated temperature to liberate alumina from bauxite, for the production of aluminium and other chemicals. Within Australia, this process results in 40 million tonnes of mineral residues (Red mud) each year. Over the same period, the energy production sector will produce 14 million tonnes of coal combustion products (Fly ash). Both industrial residues require impoundment storage, yet combining some of these components can produce geopolymers, an alternative to cement. Geopolymers derived from Bayer liquor and fly ash have been made successfully with a compressive strength in excess of 40 MPa after oven curing. However, any product from these industries would require large volume applications with robust operational conditions to maximise utilisation. To facilitate potential unconfined large-scale production, Bayer derived fly ash geopolymers have been optimised to achieve ambient curing. Fly ash from two different power stations have been successfully trialled showing the versatility of the Bayer liquor-ash combination for making geopolymers. PMID:28773513

  14. Optimising Ambient Setting Bayer Derived Fly Ash Geopolymers.

    PubMed

    Jamieson, Evan; Kealley, Catherine S; van Riessen, Arie; Hart, Robert D

    2016-05-19

    The Bayer process utilises high concentrations of caustic and elevated temperature to liberate alumina from bauxite, for the production of aluminium and other chemicals. Within Australia, this process results in 40 million tonnes of mineral residues (Red mud) each year. Over the same period, the energy production sector will produce 14 million tonnes of coal combustion products (Fly ash). Both industrial residues require impoundment storage, yet combining some of these components can produce geopolymers, an alternative to cement. Geopolymers derived from Bayer liquor and fly ash have been made successfully with a compressive strength in excess of 40 MPa after oven curing. However, any product from these industries would require large volume applications with robust operational conditions to maximise utilisation. To facilitate potential unconfined large-scale production, Bayer derived fly ash geopolymers have been optimised to achieve ambient curing. Fly ash from two different power stations have been successfully trialled showing the versatility of the Bayer liquor-ash combination for making geopolymers.

  15. Removal of chlorophenols from aqueous solution by fly ash.

    PubMed

    Kao, P C; Tzeng, J H; Huang, T L

    2000-09-15

    Fly ash from coal-fired thermal power plants can be used for the removal of 2-chlorophenol (2-CP) and 2,4-dichlorophenol (2,4-DCP) with enthalpy changes of about -3 kcal/mol. The amounts of 2-CP and 2,4-DCP removed are affected by the pH value of the solution. The efficiency of removal improves when the pH value is less than the pK(a) values of 2-CP and 2,4-DCP, respectively. The adsorbed amount of chlorophenol by fly ash is also affected by particle diameter, carbon content, and the specific surface area of the ash used in this study. As expected, more adsorption takes place with fly ash of higher carbon content and larger specific surface area. Moreover, the adsorbed amount of chlorophenol is not influenced by the matrix in the wastewater, as shown by studying the removal of 2-CP and 2, 4-DCP in wastewater from a synthetic fiber plant. Chlorophenols in the wastewater were also removed efficiently through a fly ash column, with breakthrough times being inversely proportional to flow rates.

  16. Enhancing performance and durability of slag made from incinerator bottom ash and fly ash.

    PubMed

    Chiou, Ing-Jia; Wang, Kuen-Sheng; Tsai, Chen-Chiu

    2009-02-01

    This work presents a method capable of melting the incinerator bottom ash and fly ash in a plasma furnace. The performance of slag and the strategies for recycling of bottom ash and fly ash are improved by adjusting chemical components of bottom ash and fly ash. Ashes are separated by a magnetic process to improve the performance of slag. Analytical results indicate that the air-cooled slag (ACS) and magnetic-separated slag (MSS) have hardness levels below 590 MPa, indicating fragility. Additionally, the hardness of crystallized slag (RTS) is between 655 and 686 MPa, indicating toughness. The leached concentrations of heavy metals for these three slags are all below the regulatory limits. ACS appears to have better chemical stability than MSS, and is not significantly different from RTS. In the potential alkali-silica reactivity of slag, MSS falls on the border between the harmless zone and the potentially harmful zone. ACS and RTS fall in the harmless zone. Hence, the magnetic separation procedure of ashes does not significantly improve the quality of slag. However, RTS appears to improve its quality.

  17. [Spectrophotometric determination of trace chromium in fly ash].

    PubMed

    Xia, Chang-bin; He, Xiang-zhu; Huang, Nian-dong; Shi, Hong-wen

    2003-02-01

    In HNO3 medium the fading reaction of arsenazo III oxidated with Cr2O7(2-) was used as to determine trace Cr in fly ash containing Cr. The results show that the fading reaction has high sensitivity in the medium of 3.2 mol.L-1 nitric acid, the molar absorptivity of 3.9 x 10(6) L.mol-1.cm-1 at 520 nm, and Beer's law is obeyed for Cr (VI) in the range of 0.0-40.0 micrograms.L-1. Contents of Cr in fly ash were determined with satisfactory results.

  18. Continuous air agglomeration method for high carbon fly ash beneficiation

    DOEpatents

    Gray, McMahon L.; Champagne, Kenneth J.; Finseth, Dennis H.

    2000-01-01

    The carbon and mineral components of fly ash are effectively separated by a continuous air agglomeration method, resulting in a substantially carboree mineral stream and a highly concentrated carbon product. The method involves mixing the fly ash comprised of carbon and inorganic mineral matter with a liquid hydrocarbon to form a slurry, contacting the slurry with an aqueous solution, dispersing the hydrocarbon slurry into small droplets within the aqueous solution by mechanical mixing and/or aeration, concentrating the inorganic mineral matter in the aqueous solution, agglomerating the carbon and hydrocarbon in the form of droplets, collecting the droplets, separating the hydrocarbon from the concentrated carbon product, and recycling the hydrocarbon.

  19. Utilization of fly ash as engineering pellet aggregates

    NASA Astrophysics Data System (ADS)

    Arslan, Haydar; Baykal, Gokhan

    2006-07-01

    It has been recognized that there exists a serious need for recovery and reuse of industrial wastes. Agglomeration by pelletization method can alleviate the problems associated with fly ash. The objective of this study was to evaluate the material properties of manufactured aggregates produced from fly ash and cement mixing by pelletization method. Engineering properties of the manufactured aggregates were evaluated experimentally. Crushing strength, specific gravity, water absorption, particle size distribution, surface characteristics and shear strength properties of the manufactured aggregates were evaluated. For all practical purposes, the study showed that the manufactured aggregates are a good alternative for wide range civil engineering applications.

  20. Speciation and mobility of cadmium in straw and wood combustion fly ash.

    PubMed

    Hansen, H K; Pedersen, A J; Ottosen, L M; Villumsen, A

    2001-10-01

    Two fly ashes from biomass combustion have been analysed regarding cadmium speciation and mobility. A fly ash from straw combustion contained 10 mg Cd/kg dry matter, and around 50% of the cadmium was leachable in water. The possible main speciation of cadmium in this fly ash was CdCl2. When adding this fly ash to agricultural soil a threat for groundwater contamination and plant uptake is existing. A fly ash from wood chip combustion had 28.6 mg Cd/kg dry matter. In this fly ash, the cadmium was bound more heavily, with only small amounts of cadmium leached in mild extractants. A possible speciation of cadmium in this fly ash was as oxide or as CdSiO3. Long-term effects and accumulation of cadmium could be a problem when adding this fly ash to agricultural or forest soils.

  1. Hydrothermal reactions of fly ash. Final report

    SciTech Connect

    Brown, P.W.

    1995-12-31

    The emphasis of the work done has been to determine the reactivities of two ashes believed to be representative of those generated. A bituminous ash and a lignitic ash have been investigated. The reactions of these ashes undergo when subjected to mild hydrothermal conditions were explored. The nature of the reactions which the ashes undergo when alkaline activators, calcium hydroxide and calcium sulfate are present was also investigated. It was determined that calcium silicate hydrate, calcium aluminate hydrate, and the calcium sulfoaluminate hydrate ettringite form under these conditions. It appears 3CaO{center_dot}Al{sub 2}O{sub 3}{center_dot}3CaSO{sub 4}{center_dot}32H{sub 2}O (ettringite) formation needs to be considered in ashes which contain significant amounts of sulfate. Therefore the stability region for ettringite was established. It was also determined that calcium silicate hydrate, exhibiting a high internal surface area, will readily form with hydrothermal treatment between 50{degrees} and 100{degrees}C. This phase is likely to have a significant capacity to take up heavy metals and oxyanions and this ability is being explored.

  2. Hydration reactions of cement combinations containing vitrified incinerator fly ash

    SciTech Connect

    Dyer, Thomas D.; Dhir, Ravindra K

    2004-05-01

    One treatment option for municipal solid waste incinerator fly ash (IFA) is vitrification. The process yields a material containing reduced levels of trace metals relative to the original ash. The material is glassy and potentially suitable as a cement component in concrete. This paper examines the vitrification of an IFA and studies the hydration reactions of combinations of this vitrified material and Portland cement (PC). Isothermal conduction calorimetry, powder X-ray diffraction (XRD), thermogravimetry (TG) and scanning electron microscopy were employed to study the hydration reactions. As the levels of vitrified ash increase, the quantities of AFt phase produced decrease, whilst quantities of AFm phase increase, due to the reduced levels of sulfate in the vitrified ash. The levels of calcium silicate hydrate (CSH) gel (inferred from estimates of quantities of gel-bound water) remain constant at 28 days regardless of vitrified ash content, indicating that the material is contributing toward the formation of this product.

  3. Phenolic acids as bioindicators of fly ash deposit revegetation

    SciTech Connect

    L. Djurdjevic; M. Mitrovic; P. Pavlovic; G. Gajic; O. Kostic

    2006-05-15

    The floristic composition, the abundance, and the cover of pioneer plant species of spontaneously formed plant communities and the content of total phenolics and phenolic acids, as humus constituents, of an ash deposit after 7 years of recultivation were studied. The restoration of both the soil and the vegetation on the ash deposits of the 'Nikola Tesla-A' thermoelectric power plant in Obrenovac (Serbia) is an extremely slow process. Unfavorable physical and chemical characteristics, the toxicity of fly ash, and extreme microclimatic conditions prevented the development of compact plant cover. The abundance and cover of plants increased from the central part of the deposit towards its edges. Festuca rubra L., Crepis setosa Hall., Erigeron canadensis L., Cirsium arvense (L.) Scop., Calamagrostis epigeios (L.) Roth., and Tamarix gallica L. were the most abundant species, thus giving the highest cover. Humus generated during the decomposition process of plant remains represents a completely new product absent in the ash as the starting material. The amount of total phenolics and phenolic acids in fly ash increased from the center of the deposit towards its edges in correlation with the increase in plant abundance and cover. The presence of phenolic acids indicates the ongoing process of humus formation in the ash, in which the most abundant pioneer plants of spontaneously formed plant communities play the main role. Phenolic compounds can serve as reliable bioindicators in an assessment of the success of the recultivation process of thermoelectric power plants' ash deposits.

  4. Effect of inhalation of coal fly ash on vitamin A distribution in organs of the rat.

    PubMed

    Chauhan, S S; Banerjee, R; Misra, U K

    1985-01-01

    Fly ash contains several polycyclic aromatic hydrocarbons. The effect of inhalation of coal fly ash on vitamin A distribution in various organs of rat has been studied. Inhalation of fly ash for 6 h daily, for 15 d, decreased vitamin A content in liver. The absorption of orally given [3H]retinyl acetate was decreased and so was its localization in liver of rats inhaling coal fly ash.

  5. Elemental analyses of chars isolated from a biomass gasifier fly ash

    Treesearch

    Thomas L. Eberhardt; Hui Pan

    2012-01-01

    Processing of pine wood chips in a pilot-scale downdraft gasifier generated a carbon-rich fly ash as a byproduct. Studies on biomass-derived fly ashes have generally focused on their direct characterisation, as generated, to develop options for utilisation or disposal. Analogous to studies on coal-derived fly ashes, strategies were applied here to assess the...

  6. Leaching characteristics of fly ash from Chinese medical waste incineration.

    PubMed

    Tan, Zhongxin; Xiao, Gang

    2012-03-01

    Many of the characteristics of typical medical waste ash can be found by using ash leaching experiments. The present study investigated the characteristics of fly ash derived from incineration of medical waste in China. The particle diameter of the fly ash was in the range 154-900 μm. Elemental analyses of the fly ash indicated that it contained calcium, aluminium, iron, sodium, potassium and magnesium, and that copper, lead, chromium and mercury were the dominant heavy metals it contained. As leaching time was increased the leaching concentrations of the heavy metals increased and the leaching toxicity was augmented. When the pH was neutral, the concentrations of most heavy metals in the leachate were minimum whereas when the pH was alkali or acid, the leaching toxicity was greatly enhanced. High temperature melting was found to be a good method of fixing heavy metals, and the main components of the sinter were Fe3O4, SiO2, CaSO4 and CaSiO3, etc.

  7. Ultrasonic studies of fly ash/polyurea composites

    NASA Astrophysics Data System (ADS)

    Qiao, Jing; Amirkhizi, Alireza V.; Nemat-Nasser, Sia; Wu, Gaohui

    2013-04-01

    Due to its excellent thermo-mechanical properties, polyurea is attracting more and more attention in blast-mitigating applications. In order to enhance its capability of blast-induced stress-wave management, we seek to develop polyurea-based composites in this work. Fly ash which consists of hollow particles with porous shell and low apparent density was chosen as filler and a series of fly ash/polyurea composites with various fly ash volume fractions were fabricated. The dynamic mechanical behavior of the composites was determined by a personal computer (PC) based ultrasonic system in the 0.5-2MHz frequency range between -60°C to 30°C temperatures. Velocity and attenuation of both longitudinal and shear ultrasonic waves were measured. The complex longitudinal and shear moduli were then computed from these measurements. Combining these results provided an estimate of the complex bulk and Young's moduli of the fly ash/polyurea composites at high frequencies. These results will be presented and compared with those of pure polyurea elastomer.

  8. MERCURY CAPTURE ON COAL COMBUSTION FLY ASH. (R827649)

    EPA Science Inventory

    A study was performed at the Energy and Environmental Research Center (EERC) to test the hypotheses that (1) different carbon types contained in coal combustion fly ash have variable sorption capabilities relative to mercury and (2) the inorganic fraction of coal combustion fl...

  9. Thermal characteristics of a Class F fly ash

    SciTech Connect

    Gangadhara Rao, M.V.B.B.; Kolay, P.K.; Singh, D.N.

    1998-06-01

    It is necessary to evaluate thermal properties of geotechnical materials, viz. soils and rocks, for power cables and oil pipe lines and disposal of nuclear wastes. A situation may arise where the heat dissipation through the soils and rocks may not be satisfactory, leading to adoption of a backfill. Fly ash can be used in conjunction with aggregates to design a proper backfill material. The thermal characteristics of this material, in terms of its resistivity, play an important role in the design of a thermally stable backfill, i.e., Fluidized Thermal Backfill (FTB). As such it is desired to establish thermal response of the fly ash based on its physical and moisture-holding characteristics. In this paper an effort has been made to evaluate the thermal resistivity of a Class F fly ash using a laboratory thermal needle/probe. The effect of density of compaction and the moisture content on the thermal response of the fly ash has also been studied.

  10. PREFERENTIAL PARTITIONING OF PAHS AND PCBS TO COAL FLY ASH

    EPA Science Inventory

    It has long been known that fly ash has a significant capacity for the adsorption of several classes of anthropogenic pollutants, including toxic metals, nutrients and organic compounds. This adsorption capacity has been utilized by wastewater treatment plants for the removal of ...

  11. Sorption and chemical transformation of PAHs on coal fly ash

    SciTech Connect

    Mamantov, G.; Wehry, E.L.

    1992-01-01

    The results obtained to date indicate that toluene is a useful probe solute'' for measuring the relative affinities of various fly ash fractions for aromatic solutes. In general, the adsorption isotherms obtained for toluene on fly ash fractions can be fit to a Freundlich adsorption isotherm equation, which implies that the adsorbent surface in question is heterogeneous. For most fly ash fractions studied thus far, the measured heat of adsorption decreases as the quantity of toluene injected onto the column increases. This observation also indicates that the fly ash surfaces are heterogeneous. For a homogeneous (or nearly homogeneous) surface, virtually all adsorption sites'' for a particular solute exhibit approximately the same affinity for the solute; hence, the measured heat of adsorption is virtually independent of the amount of solute that is brought into contact with the surface. However, when the surface is heterogeneous, the measured heat of adsorption decreases as the amount of solute is increased; this variation can be used to make inferences regarding surface site energy distributions if certain assumptions and approximations are made. Data obtained to date are summarized.

  12. PREFERENTIAL PARTITIONING OF PAHS AND PCBS TO COAL FLY ASH

    EPA Science Inventory

    It has long been known that fly ash has a significant capacity for the adsorption of several classes of anthropogenic pollutants, including toxic metals, nutrients and organic compounds. This adsorption capacity has been utilized by wastewater treatment plants for the removal of ...

  13. MERCURY CAPTURE ON COAL COMBUSTION FLY ASH. (R827649)

    EPA Science Inventory

    A study was performed at the Energy and Environmental Research Center (EERC) to test the hypotheses that (1) different carbon types contained in coal combustion fly ash have variable sorption capabilities relative to mercury and (2) the inorganic fraction of coal combustion fl...

  14. Characterization of ash cenospheres in fly ash from Australian power stations

    SciTech Connect

    Ling-ngee Ngu; Hongwei Wu; Dong-ke Zhang

    2007-12-15

    Ash cenospheres in fly ashes from five Australian power stations have been characterized. The experimental data show that ash cenosphere yield varies across the power stations. Ash partitioning occurred in the process of ash cenosphere formation during combustion. Contradictory to conclusions from the literature, iron does not seem to be essential to ash cenosphere formation in the cases examined in the present work. Further investigation was also undertaken on a series of size-fractioned ash cenosphere samples from Tarong power station. It is found that about 70 wt% of ash cenospheres in the bulk sample have sizes between 45 and 150 {mu}m. There are two different ash cenosphere structures, that is, single-ring structure and network structure. The percentage of ash cenospheres of a network structure increases with increasing ash cenosphere size. Small ash cenospheres (in the size fractions {lt}150 {mu}m) have a high SiO{sub 2}/Al{sub 2}O{sub 3} ratio, and the majority of the ash cenospheres are spherical and of a single-ring structure. Large ash cenosphere particles (in the size fractions of 150-250 {mu}m and {gt}250 {mu}m) have a low SiO{sub 2}/Al{sub 2}O{sub 3} ratio, and a high proportion of the ash cenospheres are nonspherical and of a network structure. A novel quantitative technique has been developed to measure the diameter and wall thickness of ash cenospheres on a particle-to-particle basis. A monolayer of size-fractioned ash cenospheres was dispersed on a pellet, which was then polished carefully before being examined using a scanning electron microscope and image analysis. The ash cenosphere wall thickness broadly increases with increasing ash cenosphere size. The ratios between wall thickness and diameter of ash cenospheres are limited between an upper bound of about 10.5% and a lower bound of about 2.5%, irrespective of the ash cenosphere size. 52 refs., 9 figs., 4 tabs.

  15. Recovery of gallium and vanadium from gasification fly ash.

    PubMed

    Font, Oriol; Querol, Xavier; Juan, Roberto; Casado, Raquel; Ruiz, Carmen R; López-Soler, Angel; Coca, Pilar; García Peña, Francisco

    2007-01-31

    The Puertollano Integrated Coal Gasification Combined Cycle (IGCC) Power Plant (Spain) fly ash is characterized by a relatively high content of Ga and V, which occurs mainly as Ga2O3 and as Ga3+ and V3+ substituting for Al3+ in the Al-Si fly ash glass matrix. Investigations focused on evaluating the potential recovery of Ga and V from these fly ashes. Several NaOH based extraction tests were performed on the IGCC fly ash, at different temperatures, NaOH/fly ash (NaOH/FA) ratios, NaOH concentrations and extraction times. The optimal Ga extraction conditions was determined as 25 degrees C, NaOH 0.7-1 M, NaOH/FA ratio of 5 L/kg and 6 h, attaining Ga extraction yields of 60-86%, equivalent to 197-275 mg of Ga/kg of fly ash. Re-circulation of leachates increased initial Ga concentrations (25-38 mg/L) to 188-215 mg/L, while reducing both content of impurities and NaOH consumption. Carbonation of concentrated Ga leachate demonstrated that 99% of the bulk Ga content in the leachate precipitates at pH 7.4. At pH 10.5 significant proportions of impurities, mainly Al (91%), co-precipitate while >98% of the bulk Ga remains in solution. A second carbonation of the remaining solution (at pH 7.5) recovers the 98.8% of the bulk Ga. Re-dissolution (at pH 0) of the precipitate increases Ga purity from 7 to 30%, this being a suitable Ga end product for further purification by electrolysis. This method produces higher recovery efficiency than currently applied for Ga on an industrial scale. In contrast, low V extraction yields (<64%) were obtained even when using extreme alkaline extraction conditions, which given the current marked price of this element, limits considerably the feasibility of V recovery from IGCC fly ash.

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  17. Photolysis of polycyclic aromatic hydrocarbons adsorbed on fly ash

    SciTech Connect

    Behymer, T.D.

    1987-01-01

    Polycyclic aromatic hydrocarbons (PAH) are formed by the combustion of almost any fuel under oxygen-deficient conditions. Previous laboratory studies have found that many PAH degrade with lifetimes as short as a few hours; however, studies of marine and lacustrine sediments, the ultimate sinks of PAH, have shown relative abundances of PAH which are similar to those in combustion sources; this suggests that PAH are stable in the atmosphere. Eighteen PAH adsorbed on carbon black and fifteen coal fly ashes of varying physical and chemical composition were photolyzed in order to study their atmospheric fate. Photolytic half-lives for these particle-bound PAH were found to be highly dependent on the substrate onto which they were adsorbed. On low-carbon fly ash, PAH showed a wide range of half-lives, indicating a relationship between PAH structure and photochemical reactivity. However, PAH on carbon black and fly ashes with a high-carbon content, show similar half-lives for most PAH including reactive PAH such as anthracene and benzo(a)pyrene. This indicates a photolytic process that is independent of structure and dependent on the physical and chemical nature of the fly ash. Surprisingly, no other parameter accounts for observed PAH reactivity. Substrate characteristics such as surface area, porosity, particle size, surface pH, and iron content have all been suggested to influence the rate of PAH degradation. However, these parameters, measured for substrates studied in this thesis, do not correlate with PAH reactivity. Because carbon black and high-carbon fly ashes stabilize reactive PAH, it is these substrates which would facilitate the transport of PAH from combustion sources through the atmosphere to ultimate sinks.

  18. Kinetics of coal fly ash chlorination by phosgene

    SciTech Connect

    Adelman, D.J.

    1984-06-01

    The kinetics of the reaction between phosgene and a fly ash composed of 97 weight percent alumina and silica has been studied over a temperature range of 450 to 800/sup 0/C and a phosgene partial pressure range of 0.02 to 0.9 atm. A microbalance was used in obtaining initial conversion rate and extended conversion-time data, and B.E.T. surface areas and specific phosgene chemisorption weights as functions of conversion. Intrinsic kinetic parameters and constant alumina to silica molar reaction ratio were determined over a fly ash conversion range of 0 to 0.375. The reaction is first order with respect to phosgene partial pressure. The shrinking-core model was successfully applied to predict fly ash conversion versus time data for the full phosgene partial pressure range and for temperatures up to 600/sup 0/C. An activation energy of 40.8 kcal/M and a frequency factor of 4.7E07 cm/min were used in the model. The results of the kinetic study were utilized in the preliminary design of a fly ash chlorination reactor. It is predicted that four reactors with beds 3 m in diameter and 2.36 m tall could process the 272,000 metric tons of fly ash collected annually by a 1000 megawatt power station. Spherical pellets with a diameter of 0.25 cm would be reacted at 700/sup 0/C to recover 67% of the alumina and 13% of the silica. 71 references, 24 figures, 8 tables.

  19. Kinetics of coal fly ash chlorination by phosgene

    SciTech Connect

    Adelman, D.J.

    1984-01-01

    The kinetics of the reaction between phosgene and a fly ash composed of 97 weight percent alumina and silica was studied over a temperature range of 450 to 800/sup 0/C and a phosgene partial pressure range of 0.02 to 0.9 atm. A microbalance was used in obtaining initial conversion rate and extended conversion-time data, and B.E.T. surface areas and specific phosgene chemisorption weights as functions of conversion. Intrinsic kinetic parameters and a constant alumina to silica molar reaction ratio were determined over a fly ash conversion range of 0 to 0.375. The reaction is first order with respect to phosgene partial pressure. The shrinking-core model was successfully applied to predict fly ash conversion versus time data for the full phosgene partial pressure range and for temperatures up to 600/sup 0/C. An activation energy of 40.8 kcal/g-M and a frequency factor of 4.7EO7 cm/min were used in the model. The results of the kinetic study were utilized in the preliminary design of a fly ash chlorination reactor. It is predicted that four reactors with beds 3 m in diameter and 2.36 m tall could process the 272,000 metric tons of fly ash collected annually by a 1000 megawatt power station. Spherical pellets with a diameter of 0.25 cm would be reacted at 700/sup 0/C to recover 67% of the alumina and 13% of the silica.

  20. Plant nutrient availability from mixtures of fly ashes and biosolids

    SciTech Connect

    Schumann, A.W.; Summer, M.E.

    1999-10-01

    Nutrient imbalances, both deficiencies and excesses, are one reason for the poor acceptance of waste materials as fertilizer substitutes. Two greenhouse experiments were established using 24 different fly ashes with sewage sludge and poultry manure to estimate nutrient availability and imbalances to maize (Zea mays L.). The maximum maize growth attained with fly ash amendment of 80 Mg ha{sup {minus}1} was significantly less (50%) than a fertilized control treatment. The additional growth improvements obtained from mixtures with sewage sludge or poultry manure ranged from 30 to 49% and 30 to 71%, respectively. Organic materials applied alone achieved only 54 and 62% of the maximum potential, while growth on poultry manure mixtures was up to 94% of the best performing fertilized treatment. Results of foliage and soil analyses suggest that P and K were the main nutrient deficiencies, while B phytotoxicity and an imbalance in the K/Ca/Mg ratio also were likely causes of plant growth reduction. Fly ashes did not contribute significant P or K to correct soil and plant deficiencies, but more often exacerbated the imbalances by precipitation or adsorption of soil P. Sewage sludge mixed at 26% and poultry manure at 13% (DM) with fly ash had negligible effect on availability of phytotoxic fly ash B, but were good sources of P (both) and K (poultry manure). Good agreement between plant nutrition in pot experiments and previous laboratory extraction studies implies that chemical analysis, efficient formulation and optimized application rates may overcome nutrient limitations for use of wastes as fertilizer substitutes.

  1. [Fly ash and its biological effects. I. Production, utilization and physico-chemical properties of fly ash].

    PubMed

    Woźniak, H; Wiecek, E; Tenerowicz, B

    1988-01-01

    The paper includes the results of Part I of the studies designed to evaluate occupational risk of power engineering workers, i.e. people employed in plants producing fly-ashes, as well as those working in lightweight concrete plants where fly-ashes are applied as raw materials. The authors have found out that fly-ashes included mainly quartz, orthoclase and mullite. In dust samples, particles of fibrous structure have been found (probably--mullite). The content of free crystalline silica came to 31.6% in total dust and 8.9% in respirable dust. Fly-ashes contained:--naturally radioactive elements K40, Ra226, Th228 (maximum values were, respectively: 1070 Bq/kg, 222 Bq/kg, 142 Bq/kg of dust),--aromatic hydrocarbons (benzene-soluble fraction) in the amount of 0.001 to 0.003 microgram/mg, as well as admixtures of heavy metals in amounts varying largely. The dust concentrations at workplaces ranged from 1 mg/m3 to 200 mg/m3, depending on the type of work (inspection, repair of boilers). The results demonstrate that in the working environment of power engineering and lightweight concrete plants there occur agents of potentially fibrogenic and cancerogenic properties.

  2. The influence of sugarcane bagasse ash as fly ash on cement quality

    NASA Astrophysics Data System (ADS)

    Rauf, N.; Damayanti, M. C.; Pratama, S. W. I.

    2017-01-01

    Fly ash often is used as the third material for cement. The fly ash from sugarcane bagasse is usually considered as industrial waste material that can be added to the base material of cement (clinker, trash, gypsum and lime stone) for economic and environment reason. The amount of fly ash usually up to 30 % of cement material, but in this research the percentage of sugarcane bagasse ash (SBA) is added to cement material is up to 15% total weight. Then the x-rays fluorescence (XRF) was used to determine its chemical composition of raw material and cement samples. The physical properties of cement such as fineness, setting time, expansion, and compressive strength were measured using Automatic Blaine, Vicat, Autoclave, respectively. The result show that the percentage of sugarcane bagasse ash influences the quality of cement and concrete, and this is confirmed with Indonesia National Standard (SNI). It is showed that the sugarcane bagasse ash could be use as material to improve the quality of cement and will solve the environment waste material

  3. Fly ash zeolite catalyst support for Fischer-Tropsch synthesis

    NASA Astrophysics Data System (ADS)

    Campen, Adam

    This dissertation research aimed at evaluating a fly ash zeolite (FAZ) catalyst support for use in heterogeneous catalytic processes. Gas phase Fischer-Tropsch Synthesis (FTS) over a fixed-bed of the prepared catalyst/FAZ support was identified as an appropriate process for evaluation, by comparison with commercial catalyst supports (silica, alumina, and 13X). Fly ash, obtained from the Wabash River Generating Station, was first characterized using XRD, SEM/EDS, particle size, and nitrogen sorption techniques. Then, a parametric study of a two-step alkali fusion/hydrothermal treatment process for converting fly ash to zeolite frameworks was performed by varying the alkali fusion agent, agent:flyash ratio, fusion temperature, fused ash/water solution, aging time, and crystallization time. The optimal conditions for each were determined to be NaOH, 1.4 g NaOH: 1 g fly ash, 550 °C, 200 g/L, 12 hours, and 48 hours. This robust process was applied to the fly ash to obtain a faujasitic zeolite structure with increased crystallinity (40 %) and surface area (434 m2/g). Following the modification of fly ash to FAZ, ion exchange of H+ for Na+ and cobalt incipient wetness impregnation were used to prepare a FTS catalyst. FTS was performed on the catalysts at 250--300 °C, 300 psi, and with a syngas ratio H2:CO = 2. The HFAZ catalyst support loaded with 11 wt% cobalt resulted in a 75 % carbon selectivity for C5 -- C18 hydrocarbons, while methane and carbon dioxide were limited to 13 and 1 %, respectively. Catalyst characterization was performed by XRD, N2 sorption, TPR, and oxygen pulse titration to provide insight to the behavior of each catalyst. Overall, the HFAZ compared well with silica and 13X supports, and far exceeded the performance of the alumina support under the tested conditions. The successful completion of this research could add value to an underutilized waste product of coal combustion, in the form of catalyst supports in heterogeneous catalytic processes.

  4. Granulation of coal fly ash by using different types of granule agents

    NASA Astrophysics Data System (ADS)

    Agusta, H.; Nisya, F. N.; Iman, R. N.; Bilad, D. B. C.

    2017-05-01

    The use of coal produces about 5% solid pollutant in the form of ash (fly ash and bottom ash). Of the total ash produced, about 10-20% is bottom ash and 80-90% is fly ash. This study was aimed at obtaining a type of adhesive which could be used as a fly granulation material for soil conditioner. The study was conducted at the pilot plant of Surfactant and Bioenergy Research Center (SBRC) LPPM IPB from April to August 2016. The fly ash used in this study was obtained from Kalimantan. A pan granulator was used in fly ash granule making process. Granule agent materials were diluted in the concentration of 5, 10, and 15%. Different types of granule agents, namely SBRC-M, SBRC-T, and SBRC-SC were used. The formed fly ash granules were then analyzed for their physical properties including particle density, fly ash granule pH, fly ash granule durability, and fly ash granule water holding capacity. Results showed that fly ash granules made from 15% of SBRC-M had the highest particle density (0.75 g/cm3). Fly ash granules made with SBRC-M had higher pH (10) than those made by using SBRC-SC adhesive (9.3) and SBRC-T (9). SBRC-T was found as the granule agent material which produced fly ash granules with the highest durability levels on average. In this study, the use of SBRC-M granule agent resulted in higher water holding capacity (WHC) (40.62%) than did SBRC-SC (38.79%) and SBRC-T (36.85%). As a granule agent, compared to SBRC-SC and SBRC-T, SBRC-M could produce fly ash granules with highest particle density, highest pH, good durability, and best water holding capacity.

  5. Kiln dust-fly ash systems for highway bases and subbases

    SciTech Connect

    Not Available

    1982-10-01

    The purpose of this investigation was to determine the effectiveness of substituting kiln dusts for hydrated lime in lime-fly ash-aggregate road base systems. A total of 45 kiln dust samples, including 33 cement dusts and 12 lime dusts, were obtained in accordance with a standard sampling procedure. In addition, 18 fly ashes (including 5 Class C ash samples) and 6 aggregates were included in the sampling program. Kiln dust and fly ash samples were characterized by Trow, Ltd. to determine physical properties and chemical, as well as mineralogical, composition. Optimum kiln dust-fly ash ratios were developed for 66 mix combinations. Kiln dust-fly ash-aggregate compressive strength tests were performed. Engineering properties (durability, volume stability, etc.) of optimum mix combinations were tested and compared with conventional lime-fly ash-aggregate mixtures. Most kiln dust-fly ash-aggregate mixes were comparable to, and in many cases demonstrated higher early strength development than, lime-fly ash-aggregate mixes. Optimum mix strengths for kiln dust-fly ash-aggregate compositions were generally attained at kiln dust-fly ash ratios of 2:1 using cement kiln dust and 1:1 using lime kiln dust. By contrast, most lime-fly ash-aggregate mixes have lime-fly ash ratios of 1:3 or 1:4. Therefore, higher concentrations of kiln dust are required compared to commercial lime. Mixes containing Class C fly ash developed higher strengths than comparable mixes with Class F fly ash.

  6. Phenolic acids as bioindicators of fly ash deposit revegetation.

    PubMed

    Djurdjević, L; Mitrović, M; Pavlović, P; Gajić, G; Kostić, O

    2006-05-01

    The floristic composition, the abundance, and the cover of pioneer plant species of spontaneously formed plant communities and the content of total phenolics and phenolic acids, as humus constituents, of an ash deposit after 7 years of recultivation were studied. The restoration of both the soil and the vegetation on the ash deposits of the "Nikola Tesla-A" thermoelectric power plant in Obrenovac (Serbia) is an extremely slow process. Unfavorable physical and chemical characteristics, the toxicity of fly ash, and extreme microclimatic conditions prevented the development of compact plant cover. The abundance and cover of plants increased from the central part of the deposit towards its edges (ranging from 1-80%). Festuca rubra L., Crepis setosa Hall., Erigeron canadensis L., Cirsium arvense (L.) Scop., Calamagrostis epigeios (L.) Roth., and Tamarix gallica L. were the most abundant species, thus giving the highest cover. Humus generated during the decomposition process of plant remains represents a completely new product absent in the ash as the starting material. The amount of total phenolics and phenolic acids (38.07-185.16 microg/g of total phenolics and 4.12-27.28 microg/g of phenolic acids) in fly ash increased from the center of the deposit towards its edges in correlation with the increase in plant abundance and cover. Ash samples contained high amounts of ferulic, vanillic, and p-coumaric acid, while the content of both p-hydroxybenzoic and syringic acid was relatively low. The presence of phenolic acids indicates the ongoing process of humus formation in the ash, in which the most abundant pioneer plants of spontaneously formed plant communities play the main role. Phenolic compounds can serve as reliable bioindicators in an assessment of the success of the recultivation process of thermoelectric power plants' ash deposits.

  7. Element bioaccumulation from coal fly ash

    SciTech Connect

    Ogugbuaja, V.O.

    1984-01-01

    Element bioaccumulation from 2.3 ..mu..m hopper ash obtained from a power plant burning Southeast Ohio coal has been investigated. Experiments were designed to examine relationships among exposure route, dose mass, and accumulation. Ash doses of 50 and 100 mg and 50, 100, and 200 mg were administered intratracheally and intragastrically, respectively, to female Fisher rats. To evaluate the elemental distribution with time, respective groups of animals were sacrificed 3 and 14 days postexposure. Pronounced association of As with red blood cells of rats intragastrically exposed was indicated. This clearly demonstrates the reported tendency of As to bind to erythrocytes. Liver apparently accumulated most elements detected, with significant storage of particularly Fe, Se, Zn, and As. Doses of 100 and 200 mg instilled by intragastric gavage provided high concentrations of these elements; 20-115% accumulations were obtained 14 days after dosing. Kidney, spleen, and brain did not substantially accumulate the elements studied. Generally, 50 mg dose resulted in substantially higher organ elemental contents compared to other doses. Element concentrations in various tissues following pulmonary exposure were low other than for the lung which is as a result of incomplete ash clearance. Feces was a major elimination route for intragastric administration while urine was mostly a negligible elimination route.

  8. Utilization options for fly ash, bottom ash, and slag in Eastern Europe

    SciTech Connect

    Manz, O.E.

    1995-12-01

    Since 1967, at least six ash utilization symposiums have been held in the United States, with papers presented by several European authors on the utilization of coal by-products in Eastern Europe. There is currently over 80,000 megawatts of installed coal-fired capacity available in that region. Unfortunately, of the 117,778,000 tonnes of fly ash, bottom ash, and slag produced in Eastern Europe in 1989, only 13% was utilized. This paper outlines the research and levels and kinds of coal by-product utilization taking place in Eastern Europe since the late 1960s.

  9. Method for increasing the rate of compressive strength gain in hardenable mixtures containing fly ash

    DOEpatents

    Liskowitz, John W.; Wecharatana, Methi; Jaturapitakkul, Chai; Cerkanowicz, deceased, Anthony E.

    1997-01-01

    The present invention relates to concrete, mortar and other hardenable mixtures comprising cement and fly ash for use in construction. The invention provides a method for increasing the rate of strength gain of a hardenable mixture containing fly ash by exposing the fly ash to an aqueous slurry of calcium oxide (lime) prior to its incorporation into the hardenable mixture. The invention further relates to such hardenable mixtures, e.g., concrete and mortar, that contain fly ash pre-reacted with calcium oxide. In particular, the fly ash is added to a slurry of calcium oxide in water, prior to incorporating the fly ash in a hardenable mixture. The hardenable mixture may be concrete or mortar. In a specific embodiment, mortar containing fly ash treated by exposure to an aqueous lime slurry are prepared and tested for compressive strength at early time points.

  10. Method for increasing the rate of compressive strength gain in hardenable mixtures containing fly ash

    DOEpatents

    Liskowitz, J.W.; Wecharatana, M.; Jaturapitakkul, C.; Cerkanowicz, A.E.

    1997-10-28

    The present invention relates to concrete, mortar and other hardenable mixtures comprising cement and fly ash for use in construction. The invention provides a method for increasing the rate of strength gain of a hardenable mixture containing fly ash by exposing the fly ash to an aqueous slurry of calcium oxide (lime) prior to its incorporation into the hardenable mixture. The invention further relates to such hardenable mixtures, e.g., concrete and mortar, that contain fly ash pre-reacted with calcium oxide. In particular, the fly ash is added to a slurry of calcium oxide in water, prior to incorporating the fly ash in a hardenable mixture. The hardenable mixture may be concrete or mortar. In a specific embodiment, mortar containing fly ash treated by exposure to an aqueous lime slurry are prepared and tested for compressive strength at early time points. 2 figs.

  11. In vivo effect of fly ash on surface receptors of mice peritoneal macrophages

    SciTech Connect

    Dogra, S.; Khanna, A.K.; Kaw, J.L.

    1987-01-01

    Functional activity of macrophages was studied in mice up to 15 days after intraperitoneal injection of 2.5 and 5.0 mg of fly ash using in vitro parameters. Fly ash did not cause any variation in the type of cellular response. The total cell number decreased significantly by 4 days after fly ash treatment but recovered subsequently. The decrease was dose dependent. Fly ash also caused a 50% depression in the FC receptor mediated phagocytosis of IgG coated sheep erythrocytes (SRBC) by macrophages at 2 days of dust treatment. However, the recovery began earlier with 2.5 mg fly ash than with 5.0 mg fly ash. These changes were not associated with any marked changes in esterase activity of macrophages following phagocytosis of fly ash.

  12. Fly ash particles spheroidization using low temperature plasma energy

    NASA Astrophysics Data System (ADS)

    Shekhovtsov, V. V.; Volokitin, O. G.; Kondratyuk, A. A.; Vitske, R. E.

    2016-11-01

    The paper presents the investigations on producing spherical particles 65-110 μm in size using the energy of low temperature plasma (LTP). These particles are based on flow ash produced by the thermal power plant in Seversk, Tomsk region, Russia. The obtained spherical particles have no defects and are characterized by a smooth exterior surface. The test bench is designed to produce these particles. With due regard for plasma temperature field distribution, it is shown that the transition of fly ash particles to a state of viscous flow occurs at 20 mm distance from the plasma jet. The X-ray phase analysis is carried out for the both original state of fly ash powders and the particles obtained. This analysis shows that fly ash contains 56.23 wt.% SiO2; 20.61 wt.% Al2O3 and 17.55 wt.% Fe2O3 phases that mostly contribute to the integral (experimental) intensity of the diffraction maximum. The LTP treatment results in a complex redistribution of the amorphous phase amount in the obtained spherical particles, including the reduction of O2Si, phase, increase of O22Al20 and Fe2O3 phases and change in Al, O density of O22Al20 chemical unit cell.

  13. Fly-ash geo-polymer foamed concrete

    NASA Astrophysics Data System (ADS)

    Kargin, Aleksey; Baev, Vladimir; Mashkin, Nikolay

    2017-01-01

    In recent years, the interest of researchrs in using fly-ash as a raw material for the geo-polymer synthesis is increasing. Kuzbass region (in Russia) has a large amount of ash wastes generated, which defined the relevace of the study performed in this paper. Results of investigating load-bearing capacity of structural insulating material produced by geo-polymerization of fly-ash of Kemerovo hydro-electric power plant with the addition of complex activator are described in the paper. Hydrogen peroxide solution was used as the foaming agent. The activation time, the temperature of isothermal holding and hardening in normal conditions for all samples were constant. The compressive strength and the mean density of geo-polymer foamed concrete were determined. The influence of the material composition on its properties was revealed. It is found that of the geo-polymer foamed concrete with the optimum composition has hardness of 1,1-3,5 MPa at the density of 400 to 900 kg/m3. Thus, the production of the fly-ash geo-polymer concretes and mortars is feasible, justified and promising.

  14. Leaching of mixtures of biochar and fly ash

    SciTech Connect

    Palumbo, Anthony V.; Porat, Iris; Phillips, Jana R.; Amonette, James E.; Drake, Meghan M.; Brown, Steven D.; Schadt, Christopher W.

    2009-06-22

    Increasing atmospheric levels of greenhouse gases, especially CO2, and their effects on global temperature have led to interest in the possibility of carbon storage in terrestrial environments. Both the residual char from biomass pyrolysis (biochar) and fly ash from coal combustion have the potential to significantly expand terrestrial sequestration options. Both biochar and fly ash also have potentially beneficial effects on soil properties. Fly ash has been shown to increase porosity, water-holding capacity, pH, conductivity, and dissolved SO42-, CO32-, Cl- and basic cations. Adding biochar to soil generally raises pH, increases total nitrogen and total phosphorous, encourages greater root development, improves cation exchange capacity and decreases available aluminum. A combination of these benefits likely is responsible for observed increases in yields for crops such as corn and sugarcane. In addition, it has been found that soils with added biochar emit lower amounts of other greenhouse gases (methane and nitrous oxide) than do unamended soils. Biochar and fly ash amendments may be useful in promoting terrestrial carbon sequestration on currently underutilized and degraded lands. For example, about 1% of the US surface lands consist of previously mined lands or highway rights-of-way. Poorly managed lands could count for another 15% of US area. Biochar and fly ash amendments could increase productivity of these lands and increase carbon storage in the soil. Previous results showed minimal leaching of organic carbon and metals from a variety of fly ashes. In the present study, we examined the properties of mixtures of biochar, fly ash, and soil and evaluated the leaching of organic carbon and metals from these mixtures. The carbon sorption experiments showed release of carbon from biochar, rather than sorption, except at the highest concentrations in the Biochar HW sample. Similar results were obtained by others for oxidative leaching of bituminous coal, in

  15. Effect of addition of bottom ash on the rheological properties of fly ash slurry at varying temperature

    NASA Astrophysics Data System (ADS)

    Kumar, K.; Kumar, S.; Gupta, M.; Garg, H. C.

    2016-09-01

    Presently, fly ash is transporting through slurry pipeline in the thermal power plant. Aim of the present investigation is to examine the rheological behaviour of finer particle (fly ash) slurry suspension with and without addition of coarser particles (bottom ash). Mixture of fly and bottom ash is taken with proportion of 9:1, 8:2 and 7:3 (by weight). The temperature of slurry suspension is varying from 25 to 40°C at solid concentration 30 % (by weight). Rheological tests are conducted with the variation of shear rate from 100 to 300 sec-1 for all slurry samples. Addition of coarse particles of bottom ash in finer particles of fly ash slurry, leads to improve the rheological characteristics of slurry suspension. The addition of bottom ash can result substantial saving in energy consumption with reduction in relative viscosity.

  16. MSWI boiler fly ashes: magnetic separation for material recovery.

    PubMed

    De Boom, Aurore; Degrez, Marc; Hubaux, Paul; Lucion, Christian

    2011-07-01

    Nowadays, ferrous materials are usually recovered from Municipal Solid Waste Incineration (MSWI) bottom ash by magnetic separation. To our knowledge, such a physical technique has not been applied so far to other MSWI residues. This study focuses thus on the applicability of magnetic separation on boiler fly ashes (BFA). Different types of magnet are used to extract the magnetic particles. We investigate the magnetic particle composition, as well as their leaching behaviour (EN 12457-1 leaching test). The magnetic particles present higher Cr, Fe, Mn and Ni concentration than the non-magnetic (NM) fraction. Magnetic separation does not improve the leachability of the NM fraction. To approximate industrial conditions, magnetic separation is also applied to BFA mixed with water by using a pilot. BFA magnetic separation is economically evaluated. This study globally shows that it is possible to extract some magnetic particles from MSWI boiler fly ashes. However, the magnetic particles only represent from 23 to 120 g/kg of the BFA and, though they are enriched in Fe, are composed of similar elements to the raw ashes. The industrial application of magnetic separation would only be profitable if large amounts of ashes were treated (more than 15 kt/y), and the process should be ideally completed by other recovery methods or advanced treatments.

  17. Fly Ash as a Time Marker for Anthropocene Alluvial Sedimentation

    NASA Astrophysics Data System (ADS)

    Bettis, E. A., III; Grimley, D. A.; Anders, A. M.; Bates, B.; Hannan, E.

    2014-12-01

    Human land use has transformed the landscapes, ecosystems and hydrology of the North American Midcontinent. One widespread impact of this transformation is increased runoff and accelerated soil erosion, which, along with direct human channel modifications and artificial drainage, have dramatically altered hydrologic and ecological conditions in streams and rivers with far-reaching results. A legacy of this change in streams and rivers is preserved on floodplains throughout the region in sediment known as post-settlement alluvium (PSA). Documenting the spatial and temporal pattern of historic floodplain sedimentation in the drainage network is part of a larger effort to understand decadal and century-scale sediment routing through the drainage system and the role of floodplain sedimentation in carbon sequestration. Fly ash, a product of high-temperature coal combustion, began to accumulate on the landscape in the early historic period (c.a.1840-1850 in Iowa and Illinois) as coal-burning technology such as steam engines came into use after 1850; prior to which no source of fly ash was present. Release of fly ash from coal burning in power plants and steam locomotives likely peaked in the early-mid 20th century. Fly ash particles (~ 1 to 10 % magnetic) are identified by their spheroidal shape and range in size from coarse clay to silt (~1-63µ). By identifying the percentage of fly ash spheroids in the magnetic separate (10 - 60µ size range) of a soil or sediment profile, the pre-fly ash Historic surface could be discerned. Application of this technique in selected localities in eastern Iowa (Clear Creek drainage) and central Illinois (Sangamon River drainage) resulted in successful demarcation of the PSA contact in areas where the boundary was physically evident. Bolstered by this success we were able to confidently demark the PSA contact in other settings where the boundary was not as physically evident. This relatively easy to implement, inexpensive tool will

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

    PubMed

    Chindaprasirt, Prinya; Rattanasak, Ubolluk

    2010-04-01

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

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

    SciTech Connect

    Chindaprasirt, Prinya; Rattanasak, Ubolluk

    2010-04-15

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

  20. Determination of anisotropy and multimorphology in fly ash based geopolymers

    SciTech Connect

    Khan, M. Irfan Azizli, Khairun Sufian, Suriati Man, Zakaria Siyal, Ahmer Ali Ullah, Hafeez

    2015-07-22

    In this study, Malaysian coal fly ash-based geopolymers were investigated for its morphology and chemical composition using scanning electron microscopy coupled with energy dispersive X-rays (SEM-EDX). Geopolymer was synthesized using sodium hydroxide as activator. SEM studies revealed multiphasous structure of the material, composed of geopolymeric gel, partially reacted fly ashparticles and selectively leached particles. EDX analysis confirmed the chemical composition of different regions. Infra red spectroscopic studies supported the SEM-EDX analysis by confirming presence of unreacted quartzite and mullite in geopolymers. It is concluded that geopolymers possese a non uniform chemistry through out the structure.

  1. Determination of anisotropy and multimorphology in fly ash based geopolymers

    NASA Astrophysics Data System (ADS)

    Khan, M. Irfan; Azizli, Khairun; Sufian, Suriati; Man, Zakaria; Siyal, Ahmer Ali; Ullah, Hafeez

    2015-07-01

    In this study, Malaysian coal fly ash-based geopolymers were investigated for its morphology and chemical composition using scanning electron microscopy coupled with energy dispersive X-rays (SEM-EDX). Geopolymer was synthesized using sodium hydroxide as activator. SEM studies revealed multiphasous structure of the material, composed of geopolymeric gel, partially reacted fly ashparticles and selectively leached particles. EDX analysis confirmed the chemical composition of different regions. Infra red spectroscopic studies supported the SEM-EDX analysis by confirming presence of unreacted quartzite and mullite in geopolymers. It is concluded that geopolymers possese a non uniform chemistry through out the structure.

  2. Fly Ash and Mercury Oxidation/Chlorination Reactions

    SciTech Connect

    Sukh Sidhu; Patanjali Varanasi

    2008-12-31

    Mercury is a known pollutant that has detrimental effect on human health and environment. The anthropogenic emissions of mercury account for 10 to 30% of worldwide mercury emissions. There is a need to control/reduce anthropogenic mercury emissions. Many mercury control technologies are available but their effectiveness is dependent on the chemical form of mercury, because different chemical forms of mercury have different physical and chemical properties. Mercury leaves the boiler in its elemental form but goes through various transformations in the post-combustion zone. There is a need to understand how fly ash and flue gas composition affect speciation, partitioning, and reactions of mercury under the full range of post-combustion zone conditions. This knowledge can then be used to predict the chemical transformation of mercury (elemental, oxidized or particulate) in the post combustion zone and thus help with the control of mercury emissions from coal-burning power plants. To accomplish this goal present study was conducted using five coal fly ashes. These ashes were characterized and their catalytic activity was compared under selected reaction conditions in a fixed bed reactor. Based on the results from these fly ash experiments, three key components (carbon, iron oxide and calcium oxide) were chosen. These three components were then used to prepare model fly ashes. Silica/alumina was used as a base for these model fly ashes. One, two or three component model fly ashes were then prepared to investigate mercury transformation reactions. The third set of experiments was performed with CuO and CuCl2 catalysts to further understand the mercury oxidation process. Based on the results of these three studies the key components were predicted for different fly ash compositions under variety of flue gas conditions. A fixed bed reactor system was used to conduct this study. In all the experiments, the inlet concentration of Hg0(g) was maintained at 35 {micro}g/m3 using

  3. A new beneficial use for 'unusable' fly ash

    SciTech Connect

    Bhatty, J.I.; Gajda, J.

    2005-09-30

    Nearly 70 million tons of fly ash are generated annually in the US, more than 60% of which is disposed of as 'unusable' in landfills because its carbon content is too high or because it is contaminated from processing measures to limit stack emissions. This paper discusses an economic use for much of this 'unusable' fly ash as a raw material in cement manufacturing. Demonstrations have produced cements that met applicable standards, and exhibited engineering properties comparable or superior to that of those normally used to produce cement. Cement plants conducting the demonstrations realized several material, operational, fuel, and environmental benefits. The operations were smooth, stable and glitch-free. The fuel consumption declined, and the rate of cement production increased. 2 figs., 2 tabs.

  4. Sorption and chemical transformation of PAH`s on coal fly ash

    SciTech Connect

    Mamantov, G.; Wehry, E.L.

    1995-05-09

    The major objective of this work was to characterize the interactions of coal fly ash with polycyclic aromatic hydrocarbons (PAHS) and their derivatives, and to attempt to understand the influence of the surface properties of coal ash (and other atmospheric particles) on the chemical transformations of polycyclic aromatic compounds. Our studies have concentrated on the photochemical behavior of PAHs sorbed form the vapor phase on coal fly ashes, and compositional subfractions obtained therefrom. The PAHs are deposited onto the fly ash substrates from the vapor phase, using apparatus and techniques developed in this laboratory in order to simulate, as closely as possible under laboratory conditions, the processes by which PAHs deposit onto fly ash particles in the atmosphere. In this report phototransformation of pyrene sorbed on fly ash fractions, and phototransformations of 1-nitropyrene sorbed on fly ash fractions are discussed.

  5. Soil stabilization and pavement recycling with self-cementing coal fly ash

    SciTech Connect

    2008-01-15

    This manual provides design information for self-cementing coal fly ash as the sole stabilizing agent for a wide range of engineering applications. As in any process, the application of sound engineering practices, appropriate testing, and evaluation of fly ash quality and characteristics will lend themselves to successful projects using the guidelines in this manual. Topics discussed include: self-cementing coal fly ash characteristics; laboratory mix design; stabilization of clay soils; stabilisation of granular materials; construction considerations; high sulfate ash; environmental considerations for fly ash stabilization; design considerations; state specification/guidelines/standards; and a sample of a typical stabilization specification.

  6. Radiological and material characterization of high volume fly ash concrete.

    PubMed

    Ignjatović, I; Sas, Z; Dragaš, J; Somlai, J; Kovács, T

    2017-03-01

    The main goal of research presented in this paper was the material and radiological characterization of high volume fly ash concrete (HVFAC) in terms of determination of natural radionuclide content and radon emanation and exhalation coefficients. All concrete samples were made with a fly ash content between 50% and 70% of the total amount of cementitious materials from one coal burning power plant in Serbia. Physical (fresh and hardened concrete density) and mechanical properties (compressive strength, splitting tensile strength and modulus of elasticity) of concrete were tested. The radionuclide content ((226)Ra, (232)Th and (40)K) and radon massic exhalation of HVFAC samples were determined using gamma spectrometry. Determination of massic exhalation rates of HVFAC and its components using radon accumulation chamber techniques combined with a radon monitor was performed. The results show a beneficial effect of pozzolanic activity since the increase in fly ash content resulted in an increase in compressive strength of HVFAC by approximately 20% for the same mass of cement used in the mixtures. On the basis of the obtained radionuclide content of concrete components the I -indices of different HVFAC samples were calculated and compared with measured values (0.27-0.32), which were significantly below the recommended 1.0 index value. The prediction was relatively close to the measured values as the ratio between the calculated and measured I-index ranged between 0.89 and 1.14. Collected results of mechanical and radiological properties and performed calculations clearly prove that all 10 designed concretes with a certain type of fly ash are suitable for structural and non-structural applications both from a material and radiological point of view.

  7. Radon emanation fractions from concretes containing fly ash and metakaolin.

    PubMed

    Taylor-Lange, Sarah C; Juenger, Maria C G; Siegel, Jeffrey A

    2014-01-01

    Radon ((222)Rn) and progenies emanate from soil and building components and can create an indoor air quality hazard. In this study, nine concrete constituents, including the supplementary cementitious materials (SCMs) fly ash and metakaolin, were used to create eleven different concrete mixtures. We investigated the effect of constituent radium specific activity, radon effective activity and emanation fraction on the concrete emanation fraction and the radon exhalation rate. Given the serious health effects associated with radionuclide exposure, experimental results were coupled with Monte Carlo simulations to demonstrate predictive differences in the indoor radon concentration due to concrete mixture design. The results from this study show that, on average, fly ash constituents possessed radium specific activities ranging from 100 Bq/kg to 200 Bq/kg and emanation fractions ranging from 1.1% to 2.5%. The lowest emitting concrete mixture containing fly ash resulted in a 3.4% reduction in the concrete emanation fraction, owing to the relatively low emanation that exists when fly ash is part of concrete. On average, the metakaolin constituents contained radium specific activities ranging from 67 Bq/kg to 600 Bq/kg and emanation fractions ranging from 8.4% to 15.5%, and changed the total concrete emanation fraction by roughly ±5% relative to control samples. The results from this study suggest that SCMs can reduce indoor radon exposure from concrete, contingent upon SCM radionucleotide content and emanation fraction. Lastly, the experimental results provide SCM-specific concrete emanation fractions for indoor radon exposure modeling.

  8. Trace-element and phase relations in fly ash

    SciTech Connect

    Hulett, L.D.; Weinberger, A.J.; Ferguson, N.M.; Northcutt, K.J.; Lyon, W.S.

    1981-05-01

    Chemical forms of elements have been studied in fly ash specimens collected from four Tennessee Valley Authority steam plants. Matrix components have been isolated and individually analyzed to determine trace element distributions. After particle sizing and extraction of magnetic components, the aluminosilicate phases were etched in 1% HF to remove glasses comingled with mullite and quartz. Neutron activation and atomic absorption analyses showed that most of the +1- and +2-valent elements, rare earths, and certain transition metals were concentrated in the glass phases. Cr, V, Ti, Fe, Ga, and Zr, which are trivalent and tetravalent, were concentrated in the crystal phases. X-ray diffraction and elemental analyses show that the main components of the magnetic phase are ferrite compounds with compositions of approximately Fe/sub 2/ /sub 3/Al/sub 0/ /sub 7/O/sub 4/. First-row transition elements, V, Cr, Mn, Co, Cu, Ni, and Zn are concentrated by factors as high as 50 in the magnetic phases. This infers that they occur as isomorphic substitutions in the magnetic spinel lattice since such compounds are well known. Because the spinel is magnetic, a magnetic separation could be used to remove spinel, along with its associated transition metals. Scanning electron microscopy studies of mullite phases remaining after 1% etching suggest that they have resource value. As mullite and quartz crystallize during the solidification of fly ash particles, they purify themselves of trace elements by freezing them out into interstitial glass phases. An analytic scheme for routine chemical specification and pollution hazard assessment of fly ash is suggested. Studies of fly ash exposed to sluice pond waters show tht iron in the magnetic spinel phases is oxidized and subsequently adsorbed on alumino-silicate and other particles. Arsenic and molybdenum are translocated and concentrated into these iron-rich surface phases.

  9. Study on use of MSWI fly ash in ceramic tile.

    PubMed

    Haiying, Zhang; Youcai, Zhao; Jingyu, Qi

    2007-03-06

    In this work, MSWI (municipal solid waste incineration) fly ash is used as a blending in production of ceramic tile by taking advantage of its high contents of SiO(2), Al(2)O(3) and CaO. Besides, macro-performance and microstructure of the product as well as its leaching toxicity in practical application were studied by means of XRD, IR and SEM analysis, and leaching toxicity and sequential chemical extraction analysis of the product. It is found that when 20% fly ash is added, the product registers a high compressive strength of 18.6MPa/cm(2) and a low water absorption of 7.4% after being sintered at 960 degrees C. It is found that the glazed tile shows excellent resistance against leaching, in accordance with HVEP stand, of heavy metals with Cd<0.0002ppm, Pb<0.0113ppm and Zn<0.0749ppm, and Hg below the low detection limit. These results show that heavy metals are cemented among the solid lattice in the product and can hardly be extracted. Leaching toxicity of heavy metals in the product, especially Hg, Pb, Zn and Cd, is substantially reduced to less than one-tenth of that in fly ash. In addition, specifications of Hg, Pb, Zn and Cd are largely changed and only a small portion of these heavy metals exists in soluble phases. These results as a whole suggest that the use of MSWI fly ash in ceramic tile constitutes a potential means of adding value.

  10. Characterization of fly ash ceramic pellet for phosphorus removal.

    PubMed

    Li, Shiyang; Cooke, Richard A; Wang, Li; Ma, Fang; Bhattarai, Rabin

    2017-03-15

    Phosphorus has been recognized as a leading pollutant for surface water quality deterioration. In the Midwestern USA, subsurface drainage not only provides a pathway for excess water to leave the field but it also drains out nutrients like nitrogen (N) and phosphorus (P). Fly ash has been identified as one of the viable materials for phosphorus removal from contaminated waters. In this study, a ceramic pellet was manufactured using fly ash for P absorption. Three types of pellet with varying lime and clay proportions by weight (type 1: 10% lime + 30% clay, type 2: 20% lime + 20% clay, and type 3: 30% lime + 10% clay) were characterized and evaluated for absorption efficiency. The result showed that type 3 pellet (60% fly ash with 30% lime and 10% clay) had the highest porosity (14%) and absorption efficiency and saturated absorption capacity (1.98 mg P/g pellet) compared to type 1 and 2 pellets. The heavy metal leaching was the least (30 μg/L of chromium after 5 h) for type 3 pellet compared to other two. The microcosmic structure of pellet from scanning electron microscope showed the type 3 pellet had the better distribution of aluminum and iron oxide on the surface compared other two pellets. This result indicates that addition of lime and clay can improve P absorption capacity of fly ash while reducing the potential to reduce chromium leaching. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Comparison of leaching characteristics of heavy metals from bottom and fly ashes in Korea and Japan

    SciTech Connect

    Shim, Young-Sook; Rhee, Seung-Whee; Lee, Woo-Keun . E-mail: woklee@kangwon.ac.kr

    2005-07-01

    The objective of this research was to compare the leaching characteristics of heavy metals such as cadmium, chromium, copper, nickel, lead, etc., in Korean and Japanese municipal solid waste incineration (MSWI) ash. The rate of leaching of heavy metal was measured by KSLT and JTL-13, and the amount of heavy metals leached was compared with the metal content in each waste component. Finally, bio-availability testing was performed to assess the risks associated with heavy metals leached from bottom ash and fly ash. From the results, the value of neutralization ability in Japanese fly ash was four times higher than that in Korean fly ash. The reason was the difference in the content of Ca(OH){sub 2} in fly ash. The amount of lead leached exceeded the regulatory level in both Japanese and Korean fly ash. The rate of leaching was relatively low in ash with a pH in the range of 6-10. The bio-availability test in fly ash demonstrated that the amount of heavy metals leached was Pb > Cd > Cr, but the order was changed to Pb > Cr > Cd in the bottom ash. The leaching concentration of lead exceeded the Japanese risk level in all fly ashes from the two countries, but the leaching concentration of cadmium exceeded the regulatory level in Korean fly ash only.

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

    PubMed

    Osmanlioglu, Ahmet Erdal

    2014-05-01

    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.

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

    SciTech Connect

    Sinha, A.S.K.

    2008-09-15

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

  14. Subacute inhalation toxicity assessment of fly ash from industrial waste incinerators.

    PubMed

    Shim, Ilseob; Oh, Eunha; Yang, Sangyoung; Ryu, Taekwon; Soh, Jaewon; Sul, Donggeun; Kim, Pilje

    2012-09-01

    Fly ash from industrial waste incinerators has been a significant concern because of their constituent toxic heavy metals and organic compounds. The objective of this study was to identify the subacute inhalation toxicity of fly ash from industrial waste incinerators, using whole body inhalation exposure chambers. Male and female groups of Sprague-Dawley rats were exposed to fly ash by inhalation of concentrations of 0, 50, 100, 200 mg/m(3), for 6 h/day, 5 days/week for 4 weeks. There was no significant difference in body weight, and relative organ weight to body weight, between the exposure groups and the control group. Hematological examinations revealed a significant increase of monocyte counts in fly ash exposed rats and brown pigment laden macrophage was found in the lungs of rats exposed to high concentration of fly ash. A decrease of blood glucose levels and an increase in glutamate oxaloacetate transaminase activity were observed in fly ash treated rats. There was also a significant increase of lactate dehydrogenase levels in rat blood exposed fly ash. A significant dose-dependent increase of DNA damage was found in lymphocytes, spleen, bronchoalveolar lavage, liver, lung, and thymus of rats exposed to fly ash. In addition, the level of lipid peroxidation was increased in the plasma of rats exposed to a high concentration of fly ash. These results suggest that inhalation of fly ash from industrial waste incinerators can induce histopathologic, hematological, and serum biochemical changes and oxidative damage.

  15. Effect of the Additives on the Desulphurization Rate of Flash Hydrated and Agglomerated CFB Fly Ash

    NASA Astrophysics Data System (ADS)

    Li, D. X.; Li, H. L.; Xu, M.; Lu, J. F.; Liu, Q.; Zhang, J. S.; Yue, G. X.

    CFB fly ash from separators was mixed with water or the mixture of water and additives under the temperature of 363K by use of a blender. Then, this compound of fly ash and water or additives was pumped into a CFB combustion chamber by a sludge pump. Because the temperature of flue gas was high in CFB, the fly ash was hydrated fast and agglomerated in the same time. Through this process, the size of agglomerating fly ash is larger than the original particle and the relative residence time of agglomerated fly ash in CFB becomes longer. Therefore, the rate of utility of calcium in fly ash improves and the content of carbon in fly ash decreases. This results in a low Ca/S and low operational cost for CFB boiler. The additive is one key factor, which affects the rate of desulfurization of agglomerated fly ash. Effect of different additives on rate of desulfurization is not same. Cement and limestone are beneficiated to sulfur removal of agglomerated fly ash, but sodium silicate does not devote to the rate of sulfur removal of agglomerated fly ash.

  16. Revegetating fly ash landfills with Prosopis juliflora L.: impact of different amendments and Rhizobium inoculation.

    PubMed

    Rai, U N; Pandey, K; Sinha, S; Singh, A; Saxena, R; Gupta, D K

    2004-05-01

    A revegetation trial was conducted to evaluate the feasibility of growing a legume species, Prosopis juliflora L., on fly ash ameliorated with combination of various organic amendments, blue-green algal biofertilizer and Rhizobium inoculation. Significant enhancements in plant biomass, photosynthetic pigments, protein content and in vivo nitrate reductase activity were found in the plants grown on ameliorated fly ash in comparison to the plants growing in unamended fly ash or garden soil. Higher growth was obtained in fly ash amended with blue-green algae (BGA) than farmyard manure or press mud (PM), a waste from sugar-processing industry, due to the greater contribution of plant nutrients, supply of fixed nitrogen and increased availability of phosphorus. Nodulation was suppressed in different amendments of fly ash with soil in a concentration-duration-dependent manner, but not with other amendments. Plants accumulated higher amounts of Fe, Mn, Cu, Zn and Cr in various fly ash amendments than in garden soil. Further, inoculation of the plant with a fly ash tolerant Rhizobium strain conferred tolerance for the plant to grow under fly ash stress conditions with more translocation of metals to the above ground parts. The results showed the potential of P. juliflora to grow in plantations on fly ash landfills and to reduce the metal contents of fly ash by bioaccumulation in its tissues.

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

    PubMed

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

    2015-06-01

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

  18. Zeolite synthesis from fly ash and cement kiln dust

    SciTech Connect

    Grutzeck, M.W.

    1996-12-31

    Zeolites added to portland cement paste normally undergo a pozzolanic reaction. However, if the composition of the cement is modified by blending it with fly ash, the calcium silicate hydrate (C-S-H) that forms has a low CaO/SiO{sub 2} ratio which allows it to coexist with a zeolite. In fact, if one adds alkali to the system, it then becomes possible to nucleate and grow a zeolitic phase with C-S-H. Normally zeolites that form from fly ash and NaOH include NaP-1 and analcime. But when the fly ash and NaOH are mixed with cement kiln dust, cancrinite-like phases and tobermorite form instead. This implies that a zeolite-containing monolith could be produced that would exhibit both the cation-exchange and adsorptive properties of zeolites while retaining the characteristic strength and ease of use attributable to cement based materials. These composites show promise as a new class of inexpensive cation exchange and/or chemical adsorbents that can be used for large scale applications.

  19. Geopolymerisation of fly ashes with waste aluminium anodising etching solutions.

    PubMed

    Ogundiran, M B; Nugteren, H W; Witkamp, G J

    2016-10-01

    Combined management of coal combustion fly ash and waste aluminium anodising etching solutions using geopolymerisation presents economic and environmental benefits. The possibility of using waste aluminium anodising etching solution (AES) as activator to produce fly ash geopolymers in place of the commonly used silicate solutions was explored in this study. Geopolymerisation capacities of five European fly ashes with AES and the leaching of elements from their corresponding geopolymers were studied. Conventional commercial potassium silicate activator-based geopolymers were used as a reference. The geopolymers produced were subjected to physical, mechanical and leaching tests. The leaching of elements was tested on 28 days cured and crushed geopolymers using NEN 12457-4, NEN 7375, SPLP and TCLP leaching tests. After 28 days ambient curing, the geopolymers based on the etching solution activator showed compressive strength values between 51 and 84 MPa, whereas the commercial potassium silicate based geopolymers gave compressive strength values between 89 and 115 MPa. Based on the regulatory limits currently associated with the used leaching tests, all except one of the produced geopolymers (with above threshold leaching of As and Se) passed the recommended limits. The AES-geopolymer geopolymers demonstrated excellent compressive strength, although less than geopolymers made from commercial activator. Additionally, they demonstrated low element leaching potentials and therefore can be suitable for use in construction works.

  20. Service life modeling for fly ash in concrete

    SciTech Connect

    Copeland, K.

    2006-07-01

    Because virtually all durability aspects of concrete are improved with a reduction in permeability, the use of fly ash improves concrete durability. Concrete water demand is typically reduced when using fly ash leading to a lower water cementitious ratio. The Life 365 model is one example of a life cycle cost prediction model. It was originally created as a industry standard model to predict ingress of chloride in structures and mitigation technologies for controlling corrosion. This model allows users to input the actual diffusion data for a given mix design. Users can also select pre-set modifications such as fly ash to produce high performance concrete, or such corrosion inhibitors as stainless steel, epoxy coated reinforcement, or application of sealers or membranes. Other more recent computer based service life models attempt to improve on some of the perceived shortcomings of Life 365. One such model, STADIUM, predicts the movement of other ions in addition to chloride, including sulfate, hydroxyl, sodium, potassium, magnesium, and others, as well as several solid phases. The transport mechanism in this model is not limited to diffusion of ions in saturated conditions. One notable feature of STADIUM is its ability to account for movement of ions, and to adjust for coupling due to changes in concentration of various ions. This model will adjust the amount of predicted ions in solution in keeping with maximum solubilities of the respective compounds. 2 figs.

  1. Direct utilization - recovery of minerals from coal fly ash. Technical progress report, October 1, 1982-December 31, 1982

    SciTech Connect

    Burnet, G.; Murtha, M.J.; Seaverson, L.M.

    1983-02-01

    Research included an examination of the adsorbed water on coal fly ash, the utilization of phosgene as a chlorination agent, the physical adsorption and chemisorption of phosgene on fly ash particles, and the aqueous separation of chlorination products. Results of an investigation of coal fly ash powder samples using photoacoustic infrared spectroscopy showed almost complete removal of adsorbed water after drying for 30 hours at 700/sup 0/C. A thermodynamic computer simulation of the chlorination of an SiO/sub 2/ and Al/sub 2/O/sub 3/ mixture of 2:1 molar ratio with a stoichiometric amount of carbon present revealed that silica is the preferred reactant at lower temperature, but that alumina chlorination is preferred at 800/sup 0/C. Experiments using phosgene to chlorinate acid-leached Texas lignite fly ash gave information about the kinetic rate dependence of the reaction involved. Work to determine the amount of chemisorption and physical adsorption of phosgene on pellets of the leached Texas lignite ash was initiated to permit the calculation of surface reaction rates. Separation of FeCl/sub 3/ by solvent extraction improved as the chloride ion concentration of the aqueous phase increased, regardless of whether the associated cation was hydrogen or aluminum. A static equilibrium cell/furnace arrangement with ultraviolet spectroscopy capability has been confirmed to be suitable for measurement of the absorbance of vapor species. A Harper 6 in. dia rotary kiln was used to continuously sinter a limestone-soda ash-fly ash mixture in the form of 1/8 in. dia pellets. Extraction of sintered material with dilute aqueous soda ash solution gave aluminate recoveries comparable to those obtained when small samples were sintered in a benchscale tube furnace. Results are presented which show that x-ray diffraction data can be used to calculate the amounts of individual compounds in sintered samples.

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

    USGS Publications Warehouse

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

    1984-01-01

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

  3. Synthesis and characterization of zeolites prepared from industrial fly ash.

    PubMed

    Franus, Wojciech; Wdowin, Magdalena; Franus, Małgorzata

    2014-09-01

    In this paper, we present the possibility of using fly ash to produce synthetic zeolites. The synthesis class F fly ash from the Stalowa Wola SA heat and power plant was subjected to 24 h hydrothermal reaction with sodium hydroxide. Depending on the reaction conditions, three types of synthetic zeolites were formed: Na-X (20 g fly ash, 0.5 dm(3) of 3 mol · dm(-3) NaOH, 75 °C), Na-P1 (20 g fly ash, 0.5 dm(3) of 3 mol · dm(-3) NaOH, 95 °C), and sodalite (20 g fly ash, 0.8 dm(3) of 5 mol · dm(-3) NaOH + 0.4 dm(3) of 3 mol · dm(-3) NaCl, 95 °C). As synthesized materials were characterized to obtain mineral composition (X-ray diffractometry, Scanning electron microscopy-energy dispersive spectrometry), adsorption properties (Brunauer-Emmett-Teller surface area, N2 isotherm adsorption/desorption), and ion exchange capacity. The most effective reaction for zeolite preparation was when sodalite was formed and the quantitative content of zeolite from X-ray diffractometry was 90 wt%, compared with 70 wt% for the Na-X and 75 wt% for the Na-P1. Residues from each synthesis reaction were the following: mullite, quartz, and the remains of amorphous aluminosilicate glass. The best zeolitic material as characterized by highest specific surface area was Na-X at almost 166 m(2) · g(-1), while for the Na-P1 and sodalite it was 71 and 33 m(2) · g(-1), respectively. The ion exchange capacity decreased in the following order: Na-X at 1.8 meq · g(-1), Na-P1 at 0.72 meq · g(-1), and sodalite at 0.56 meq · g(-1). The resulting zeolites are competitive for commercially available materials and are used as ion exchangers in industrial wastewater and soil decontamination.

  4. Occupational exposure and DNA strand breakage of workers in bottom ash recovery and fly ash treatment plants.

    PubMed

    Chen, Hsiu-Ling; Chen, I-Ju; Chia, Tai-Pao

    2010-02-15

    Various environmental hazards and metals are liberated either into bottom ash or carried away with gases and subsequently trapped in fly ash. Many studies have reported an increase of DNA damage is related to hazardous exposure of municipal waste incinerators. By detecting DNA damage, we compared the DNA migration imposed in workers potentially exposed to hazardous substances, including PCDD/Fs, metals, and silica particles, at a bottom ash recovery plant and fly ash treatment plants in Taiwan. Higher tail moment (TMOM) was found in workers at fly ash treatment plants (7.55) than in the workers in bottom ash plants (2.64), as well as those in blue collar was higher than in white collar workers (5.72 vs. 3.95). Meanwhile, the significantly higher DNA damage was also shown in workers with high integrated exposure score than those with low. The air samplings for particle mass, Cr, and Al concentrations also showed the higher levels in fly ash treatment plants than in the workers in bottom ash plants. Meanwhile, the air samplings inside the two plants suggested that the particle size might be important to affect the workers inhaling the metal into the human body and finally caused to their DNA damage. The data concluded that an elevated DNA damage may be expected in workers at fly ash treatment plants than those at bottom ash plants; however, the occupational hazards in both types of plants, especially at different particle size interval, need more thorough assessment in future studies.

  5. Biological responses of agricultural soils to fly-ash amendment.

    PubMed

    Singh, Rajeev Pratap; Sharma, Bhavisha; Sarkar, Abhijit; Sengupta, Chandan; Singh, Pooja; Ibrahim, Mahamad Hakimi

    2014-01-01

    The volume of solid waste produced in the world is increasing annually, and disposing of such wastes is a growing problem. Fly ash (FA) is a form of solid waste that is derived from the combustion of coal. Research has shown that fly ash may be disposed of by using it to amend agricultural soils. This review addresses the feasibility of amending agricultural field soils with fly ash for the purpose of improvings oil health and enhancing the production of agricultural crops. The current annual production of major coal combustion residues (CCRs) is estimated to be -600 million worldwide, of which about 500 million t (70-80%) is FA (Ahmaruzzaman 2010). More than 112 million t of FA is generated annually in India alone, and projections show that the production (including both FA and bottom ash) may exceed 170 million t per annum by 2015 (Pandey et al. 2009; Pandey and Singh 20 I 0). Managing this industrial by-product is a big challenge, because more is produced each year, and disposal poses a growing environmental problem.Studies on FA clearly shows that its application as an amendment to agricultural soils can significantly improve soil quality, and produce higher soil fertility. What FA application method is best and what level of application is appropriate for any one soil depends on the following factors: type of soil treated, crop grown, the prevailing agro climatic condition and the character of the FA used. Although utilizing FA in agricultural soils may help address solid waste disposal problems and may enhance agricultural production, its use has potential adverse effects also. In particular, using it in agriculture may enhance amounts of radionuclides and heavy metals that reach soils, and may therefore increase organism exposures in some instances.

  6. Study on Type C Coal Fly ash as an Additive to Molding Sand for Steel Casting

    NASA Astrophysics Data System (ADS)

    Palaniappan, Jayanthi

    2017-04-01

    Study of physio-chemical properties studies such as granulometric analysis, moisture, X ray fluorescence etc. were performed with Type C coal—combustion fly ash to investigate their potential as a distinct option for molding sand in foundry, thereby reducing the dependency on latter. Technological properties study such as compressive strength, tensile strength, permeability and compaction of various compositions of fly ash molding sand (10, 20 and 30 % fly ash substitute to chemically bonded sand) were performed and compared with silica molding sand. Steel casting production using this fly ash molding sand was done and the casting surface finish and typical casting parameters were assessed. It was noted that a good quality steel casting could be produced using type C fly ash molding sand, which effectively replaced 20 % of traditional molding sand and binders thereby providing greater financial profits to the foundry and an effective way of fly ash utilization (waste management).

  7. Potential use of fly ash to soil treatment in the Morava region

    NASA Astrophysics Data System (ADS)

    Bulíková, Lucia; Kresta, František; Rochovanský, Martin

    2017-09-01

    Soil treatment by binders is a standard technology and leads to optimal utilization of excavated soils in road constructions. Soil treatment is controlled in the Czech Republic by EN 14227-15 and Technical Requirement TP 94. Soil treatment using fly ash has not been performed in the Czech Republic, although there is a sufficient normative base. Fly ash produced by burning of hard coal in the Moravian region was tested as a potential binder. Fly ash samples were mixed with loess loams (CI). Tested siliceous fly ash of class F (ASTM C618) did not showed hydraulic properties but it showed positive effect on reducing maximum dry density of mixtures, increasing the IBI value (Immediate bearing index) and decreasing tendency to volume changes when the amount of fly ash was increased. The results of laboratory tests demonstrate the possibility of using fly ashes as a binder for soil treatment.

  8. Mutagenicity and cytotoxicity of coal fly ash from fluidized-bed and conventional combustion.

    PubMed

    Mumford, J L; Lewtas, J

    1982-01-01

    In summary, fly-ash samples from a pressurized fluidized-bed combustion miniplant were found to consist of submicron, irregular particles that were cytotoxic and contained bioavailable mutagens. The fly-ash emission sample from a conventional coal-fired power plant was found to consist of spherical particles that were also cytotoxic but less mutagenic. The FBC fly ash investigated here was collected from an experimental miniplant and should not be considered representative of fly ash that may be obtained in the future from larger commercial-scale FBC plants. Further health and environmental assessment studies of coal fly-ash samples collected at multiple sites, including commercial-scale fluidized-bed and other conventional combustors, are needed to evaluate the potential health effects of coal fly ash from both types of combustion technology.

  9. Effect of fly ash preliminary calcination on the properties of geopolymer.

    PubMed

    Temuujin, J; van Riessen, A

    2009-05-30

    The influence of preliminary calcination of fly ashes on the geopolymerisation process has been studied. Preliminary calcination at 500 and 800 degrees C causes decarbonation of the fly ash while it also leads to a decrease of the amorphous content of the fly ashes from 60 to 57%. Geopolymer prepared using raw fly ash exhibited a compressive strength 55.7(9.2)MPa, while for 500 and 800 degrees C calcined samples it reduced to 54(5.8) and 44.4(5.4)MPa, respectively. The decrease in compressive strength of the geopolymers is discussed in terms of partial surface crystallisation of the fly ash particles. Reactivity of the fly ash also has been correlated with the shrinkage rate and presence of efflorescence on the surface of geopolymers.

  10. Comparative performance of geopolymers made with metakaolin and fly ash after exposure to elevated temperatures

    SciTech Connect

    Kong, Daniel L.Y.; Sanjayan, Jay G. Sagoe-Crentsil, Kwesi

    2007-12-15

    This paper presents the results of a study on the effect of elevated temperatures on geopolymers manufactured using metakaolin and fly ash of various mixture proportions. Both types of geopolymers (metakaolin and fly ash) were synthesized with sodium silicate and potassium hydroxide solutions. The strength of the fly ash-based geopolymer increased after exposure to elevated temperatures (800 deg. C). However, the strength of the corresponding metakaolin-based geopolymer decreased after similar exposure. Both types of geopolymers were subjected to thermogravimetric, scanning electron microscopy and mercury intrusion porosimetry tests. The paper concludes that the fly ash-based geopolymers have large numbers of small pores which facilitate the escape of moisture when heated, thus causing minimal damage to the geopolymer matrix. On the other hand, metakaolin geopolymers do not possess such pore distribution structures. The strength increase in fly ash geopolymers is also partly attributed to the sintering reactions of un-reacted fly ash particles.

  11. Study on Type C Coal Fly ash as an Additive to Molding Sand for Steel Casting

    NASA Astrophysics Data System (ADS)

    Palaniappan, Jayanthi

    2016-05-01

    Study of physio-chemical properties studies such as granulometric analysis, moisture, X ray fluorescence etc. were performed with Type C coal—combustion fly ash to investigate their potential as a distinct option for molding sand in foundry, thereby reducing the dependency on latter. Technological properties study such as compressive strength, tensile strength, permeability and compaction of various compositions of fly ash molding sand (10, 20 and 30 % fly ash substitute to chemically bonded sand) were performed and compared with silica molding sand. Steel casting production using this fly ash molding sand was done and the casting surface finish and typical casting parameters were assessed. It was noted that a good quality steel casting could be produced using type C fly ash molding sand, which effectively replaced 20 % of traditional molding sand and binders thereby providing greater financial profits to the foundry and an effective way of fly ash utilization (waste management).

  12. Characterisation and use of biomass fly ash in cement-based materials.

    PubMed

    Rajamma, Rejini; Ball, Richard J; Tarelho, Luís A C; Allen, Geoff C; Labrincha, João A; Ferreira, Victor M

    2009-12-30

    This paper presents results about the characterisation of the biomass fly ashes sourced from a thermal power plant and from a co-generation power plant located in Portugal, and the study of new cement formulations incorporated with the biomass fly ashes. The study includes a comparative analysis of the phase formation, setting and mechanical behaviour of the new cement-fly ash formulations based on these biomass fly ashes. Techniques such as X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), thermal gravimetric and differential thermal analysis (TG/DTA), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and environmental scanning electron spectroscopy (ESEM) were used to determine the structure and composition of the formulations. Fly ash F1 from the thermal power plant contained levels of SiO(2), Al(2)O(3) and Fe(2)O(3) indicating the possibility of exhibiting pozzolanic properties. Fly ash F2 from the co-generation plant contained a higher quantity of CaO ( approximately 25%). The fly ashes are similar to class C fly ashes according to EN 450 on the basis of chemical composition. The hydration rate and phase formation are greatly dependant on the samples' alkali content and water to binder (w/b) ratio. In cement based mortar with 10% fly ash the basic strength was maintained, however, when 20% fly ash was added the mechanical strength was around 75% of the reference cement mortar. The fly ashes contained significant levels of chloride and sulphate and it is suggested that the performance of fly ash-cement binders could be improved by the removal or control of these chemical species.

  13. Improving phosphate removal of sand infiltration system using alkaline fly ash.

    PubMed

    Cheung, K C; Venkitachalam, T H

    2000-07-01

    Septic tank effluent is customarily disposed of by soil infiltration. Coarse, sandy soil such as those found in Perth, Western Australia, exhibit low attenuation capabilities for phosphate (PO4(3-)) during effluent infiltration. Amendment of such soil with different amounts of alkaline precipitator and lagoon fly ashes was investigated as a means of reducing phosphorus (P) leakage to ground water. Alkaline precipitator fly ash possessed the highest P sorption capacity in terms of its Langmuir and Freundlich isotherm parameters during initial batch tests. The test materials were repeatedly contacted with fresh PO4(3-) solutions over 90 contacting cycles to gain a better indication of long-term P sorption capability. Again, precipitator fly ash exhibited higher P sorption capacity than lagoon fly ash and Spearwood sand. Column studies assessed the influence of various application rates of alkaline precipitator and lagoon fly ashes on the P removal of septic tank effluent. Septic tank effluent was applied at the rate of 4 cm/day to the column for 12 weeks. Concentrations of P were monitored in the column effluent. All the fly ash columns were more efficient in reducing P migration compared to the sand column. Increased levels of fly ash in the soil columns resulted in increased P attenuation. Lagoon fly ash was inferior to precipitator fly ash for P removal; high application rates of fly ash caused clogging of the infiltration bed apparently due to their lower permeability. It is reasoned that 5-15% precipitator fly ash, and less than 30% lagoon fly ash could be added to coarse sands to produce an infiltration bed, which would result in a better quality effluent than can be obtained with untreated sand alone.

  14. Direct Quantitative Analysis of Arsenic in Coal Fly Ash

    PubMed Central

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

    2012-01-01

    A rapid, simple method based on graphite furnace atomic absorption spectrometry is described for the direct determination of arsenic in coal fly ash. Solid samples were directly introduced into the atomizer without preliminary treatment. The direct analysis method was not always free of spectral matrix interference, but the stabilization of arsenic by adding palladium nitrate (chemical modifier) and the optimization of the parameters in the furnace program (temperature, rate of temperature increase, hold time, and argon gas flow) gave good results for the total arsenic determination. The optimal furnace program was determined by analyzing different concentrations of a reference material (NIST1633b), which showed the best linearity for calibration. The optimized parameters for the furnace programs for the ashing and atomization steps were as follows: temperatures of 500–1200 and 2150°C, heating rates of 100 and 500°C s−1, hold times of 90 and 7 s, and medium then maximum and medium argon gas flows, respectively. The calibration plots were linear with a correlation coefficient of 0.9699. This method was validated using arsenic-containing raw coal samples in accordance with the requirements of the mass balance calculation; the distribution rate of As in the fly ashes ranged from 101 to 119%. PMID:23251836

  15. Effect of fly ash calcination in geopolymer synthesis

    NASA Astrophysics Data System (ADS)

    Samadhi, Tjokorde Walmiki; Jatiningrum, Mirna; Arisiani, Gresia

    2015-12-01

    Geopolymer, a largely amorphous class of inorganic polymer consisting of aluminosilicate repeat units, is an environmentally attractive engineering material due to its ability to consume aluminosilicate waste as raw materials. This work studies the effect of the calcination temperature of a coal fly ash generated by a low-efficiency boiler on the mechanical strength of geopolymer mortar synthesized using a mixture of the fly ash, potassium hydroxide as the alkali activator, and locally available sand as the filler aggregate. The calcination temperature is varied between 500-700 °C, with a calcination period of 2 hours in an electric furnace. Two sand samples with different particle size distributions are used. The key response variable is the compressive strength at room temperature, measured after curing at 80 °C for 7 and 14 days. Uncalcined ash, with a carbon content of approximately 31.0%, is not amenable for geopolymer synthesis. Analysis of experimental data using the ANOVA method for general factorial design identifies significant main effects for all three experimental variables. Two-way interactions are significant, except that between sand type and curing period. Higher calcination temperature significantly improves the strength of the mortar. However, the strength of the obtained geopolymer mortars are still significantly lower than that of ordinary Portland cement mortar.

  16. Removal of hazardous metals from MSW fly ash--an evaluation of ash leaching methods.

    PubMed

    Fedje, Karin Karlfeldt; Ekberg, Christian; Skarnemark, Gunnar; Steenari, Britt-Marie

    2010-01-15

    Incineration is a commonly applied management method for municipal solid waste (MSW). However, significant amounts of potentially hazardous metal species are present in the resulting ash, and these may be leached into the environment. A common idea for cleaning the ash is to use enhanced leaching with strong mineral acids. However, due to the alkalinity of the ash, large amounts of acid are needed and this is a drawback. Therefore, this work was undertaken in order to investigate some alternative leaching media (EDTA, ammonium nitrate, ammonium chloride and a number of organic acids) and to compare them with the usual mineral acids and water. All leaching methods gave a significant increase in ash specific surface area due to removal of soluble bulk (matrix) compounds, such as CaCO(3) and alkali metal chlorides. The use of mineral acids and EDTA mobilised many elements, especially Cu, Zn and Pb, whereas the organic acids generally were not very effective as leaching agents for metals. Leaching using NH(4)NO(3) was especially effective for the release of Cu. The results show that washing of MSW filter ash with alternative leaching agents is a possible way to remove hazardous metals from MSW fly ash.

  17. CO₂ carbonation under aqueous conditions using petroleum coke combustion fly ash.

    PubMed

    González, A; Moreno, N; Navia, R

    2014-12-01

    Fly ash from petroleum coke combustion was evaluated for CO2 capture in aqueous medium. Moreover the carbonation efficiency based on different methodologies and the kinetic parameters of the process were determined. The results show that petroleum coke fly ash achieved a CO2 capture yield of 21% at the experimental conditions of 12 g L(-1), 363°K without stirring. The carbonation efficiency by petroleum coke fly ash based on reactive calcium species was within carbonation efficiencies reported by several authors. In addition, carbonation by petroleum coke fly ash follows a pseudo-second order kinetic model. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Experimental and numerical analysis of metal leaching from fly ash-amended highway bases

    SciTech Connect

    Cetin, Bora; Aydilek, Ahmet H.; Li, Lin

    2012-05-15

    Highlights: Black-Right-Pointing-Pointer This study is the evaluation of leaching potential of fly ash-lime mixed soils. Black-Right-Pointing-Pointer This objective is met with experimental and numerical analysis. Black-Right-Pointing-Pointer Zn leaching decreases with increase in fly ash content while Ba, B, Cu increases. Black-Right-Pointing-Pointer Decrease in lime content promoted leaching of Ba, B and Cu while Zn increases. Black-Right-Pointing-Pointer Numerical analysis predicted lower field metal concentrations. - Abstract: A study was conducted to evaluate the leaching potential of unpaved road materials (URM) mixed with lime activated high carbon fly ashes and to evaluate groundwater impacts of barium, boron, copper, and zinc leaching. This objective was met by a combination of batch water leach tests, column leach tests, and computer modeling. The laboratory tests were conducted on soil alone, fly ash alone, and URM-fly ash-lime kiln dust mixtures. The results indicated that an increase in fly ash and lime content has significant effects on leaching behavior of heavy metals from URM-fly ash mixture. An increase in fly ash content and a decrease in lime content promoted leaching of Ba, B and Cu whereas Zn leaching was primarily affected by the fly ash content. Numerically predicted field metal concentrations were significantly lower than the peak metal concentrations obtained in laboratory column leach tests, and field concentrations decreased with time and distance due to dispersion in soil vadose zone.

  19. Size characterization of incinerator fly ash using sedimentation/steric field-flow fractionation.

    PubMed

    Kimt, Won-Suk; Lee, Dai Woon; Lee, Seungho

    2002-02-15

    Fly ash particles emitted from municipal solid waste-incinerators are of environmental concern. This study aims to investigate the applicability of sedimentation/steric field-flow fractionation (Sd/StFFF) and to develop a Sd/StFFF method for the separation and size characterization of incinerator fly ash. This study focuses on the fly ash particles larger than approxiamtely 1 microm, which comprise more than 90% (w/w) of the fly ash. Fly ash is a complex mixture of particles having various chemical compositions, sizes, shapes, and densities. Prior to Sd/StFFF analysis, fly ash particles are prefractionated into six density classes using a modified centrifugal procedure. It was found that fly ash particles are most abundant in the density range between 2.4 and 2.8 g/cm3. Different density fractions seem to contain particles of different chemical compositions. The Sd/StFFF conditions for the size-characterization of fly ash are sample concentration, approximately 0.3% (w/v); dispersing medium, 50% ethanol in water; and carrier liquid, water with 1.0% FL-70 (ionic strength approximately 0.012 M). Sd/StFFF data show no significant differences in size distribution among different density fractions. Generally, the sizes obtained from Sd/StFFF are larger than those obtained from a Coulter Multisizer and microscopy, probably because of the irregular shapes of the fly ash particles.

  20. Chemical and engineering properties of fired bricks containing 50 weight percent of class F fly ash

    USGS Publications Warehouse

    Chou, I.-Ming; Patel, V.; Laird, C.J.; Ho, K.K.

    2001-01-01

    The generation of fly ash during coal combustion represents a considerable solid waste disposal problem in the state of Illinois and nationwide. In fact, the majority of the three million tons of fly ash produced from burning Illinois bituminous coals is disposed of in landfills. The purpose of this study was to obtain a preliminary assessment of the technical feasibility of mitigating this solid waste problem by making fired bricks with the large volume of fly ash generated from burning Illinois coals. Test bricks were produced by the extrusion method with increasing amounts (20-50% by weight) of fly ash as a replacement for conventional raw materials. The chemical characteristics and engineering properties of the test bricks produced with and without 50 wt% of fly ash substitutions were analyzed and compared. The properties of the test bricks containing fly ash were at least comparable to, if not better than, those of standard test bricks made without fly ash and met the commercial specifications for fired bricks. The positive results of this study suggest that further study on test bricks with fly ash substitutions of greater than 50wt% is warranted. Successful results could have an important impact in reducing the waste disposal problem related to class F fly ash while providing the brick industry with a new low cost raw material. Copyright ?? 2001 Taylor & Francis.

  1. Production of fired construction brick from high sulfate-containing fly ash with boric acid addition.

    PubMed

    Başpinar, M Serhat; Kahraman, Erhan; Görhan, Gökhan; Demir, Ismail

    2010-01-01

    The increase of power plant capacity has led to the production of an increasing amount of fly ash that causes high environmental impact in Turkey. Some of the fly ash is utilized within the fired brick industry but high sulfate-containing fly ash creates severe problems during sintering of the fired brick. This study attempted to investigate the potential for converting high sulfate-containing fly ash into useful material for the construction industry by the addition of boric acid. The chemical and mineralogical composition of fly ash and clay were investigated. Boric acid (H(3)BO(3)) was added to fly ash-clay mixtures with up to 5 wt.%. Six different series of test samples were produced by uniaxial pressing. The samples were fired at the industrial clay-brick firing temperatures of 800, 900 and 1000 degrees C. The microstructures of the fired samples were investigated by scanning electron microscopy and some physical and mechanical properties were measured. It was concluded that the firing at conventional brick firing temperature of high sulfate fly ash without any addition of boric acid resulted in very weak strength bricks. The addition of boric acid and clay simultaneously to the high sulfate- containing fly ash brick dramatically increased the compressive strength of the samples at a firing temperature of 1000 degrees C by modifying the sintering behaviour of high sulfate fly ash.

  2. Fly ash design manual for road and site applications. Volume 1. Dry or conditioned placement

    SciTech Connect

    DiGioia, A.M.; McLaren, R.J.; Burns, D.L.; Miller, D.E.

    1986-02-01

    This updated design manual describes the use of fly ash as a construction material for use as structural and nonstructural fills, backfills, embankments, base courses, soil stabilization, land reclamation and other high volume uses. The manual details the physical, engineering, and chemical properties of bituminous, subbituminous and lignite fly ash. Included are field and laboratory testing methods, design data, procedures and examples, specifications, quality control, and pre- and post-construction monitoring. Volume 1 describes uses where fly ash is used dry or conditioned with small amounts of moisture. Volume 2 describes uses where fly ash is placed as a slurry with relatively large amounts of water.

  3. Micromorphology use for visualization of fly-ash distribution in sandy material

    NASA Astrophysics Data System (ADS)

    Kodesova, R.; Kapicka, A.

    2009-04-01

    Fly-ash migration in three sands of various particle size distributions and consequently various porosities, was studied in the laboratory. The fly-ash was applied on the top of all sands packed in plastic cylinders followed by pulse infiltrations. Water regime was monitored using the soil water content sensors and tensiometers. Kappameter SM400 (Petrovský at al., 2004) was used to monitor migration of ferrimagnetic particles-tracers presented in the fly-ash. Undisturbed samples of sands polluted by fly-ash were taken at the end of the experiments to study final fly-ash distribution in thin sections. Images showed that while fly-ash migrates freely thought the course sandy material, in the other two sands fly-ash is accumulated in few bottle neck pores. However, fly-ash mobility was documented in both cases. Information about image porosities and pore blocking will be used as input data for numerical simulation of observed fly-ash transport. Acknowledgement: Authors acknowledge the financial support of the Grant Agency of Academy of Sciences of the Czech Republic grant No. A300120701, and the Ministry of Education, Youth and Sports grant No. MSM 6046070901.

  4. Genotoxic effects of fly ash in bacteria, mammalian cells and animals

    SciTech Connect

    Morris, D.L.; Connor, T.H.; Harper, J.B.; Ward, J.B. Jr.; Legator, M.S. )

    1989-01-01

    The increasing use of fossil fuels has raised concerns about possible deleterious health effects of the final combustion product, fly ash. Seven ash samples from coal sources obtained from Battelle Columbus Laboratories were evaluated in the Salmonella/mammalian microsome mutagenicity assay to determine their mutagenic potential. While dimethyl sulfoxide extracts of five samples showed no mutagenicity, sample 102 caused an increase in the number of revertants per plate over controls in TA100 and TA98 with activation by liver homogenate (2-fold and 2.4-fold, respectively), and without (2-fold and 6-fold). This ash was thus evaluated in whole animal studies. Animals treated by inhalation or oral gavage were assayed for the presence of mutagens in the urine, micronuclei in polychromatic erythrocytes, and chromosomal aberrations in metaphase bone marrow cells. Those animals treated by inhalation were also examined for local damage in the lung. The assay for mutagens in the urine was negative as shown by the Ames assay with TA100 and TA98 and there was no increase in micronuclei or in metaphase aberrations. Histological sections from the animals treated by inhalation did not show the presence of particles, macrophage infiltrations and generalized lung damage. We tested the same fly ash with an in vitro cell transformation assay with the cell line Balb/c 3T3 subclone A31-1-13. Although there was not an increase in Type III foci, there was a dose-dependent increase of Type II foci in the treated cells over the controls. In one assay, there was approximately a 14-fold increase in Type II foci in the highest dose (2 mg/ml) compared to the solvent control. One other ash sample induced cell transformation without being markedly cytotoxic, while a third sample was highly toxic but did not induce transformation.

  5. Genotoxic effects of fly ash in bacteria, mammalian cells and animals.

    PubMed

    Morris, D L; Connor, T H; Harper, J B; Ward, J B; Legator, M S

    1989-01-01

    The increasing use of fossil fuels has raised concerns about possible deleterious health effects of the final combustion product, fly ash. Seven ash samples from coal sources obtained from Battelle Columbus Laboratories were evaluated in the Salmonella/mammalian microsome mutagenicity assay to determine their mutagenic potential. While dimethyl sulfoxide extracts of five samples showed no mutagenicity, sample 102 caused an increase in the number of revertants per plate over controls in TA100 and TA98 with activation by liver homogenate (2-fold and 2.4-fold, respectively), and without (2-fold and 6-fold). This ash was thus evaluated in whole animal studies. Animals treated by inhalation or oral gavage were assayed for the presence of mutagens in the urine, micronuclei in polychromatic erythrocytes, and chromosomal aberrations in metaphase bone marrow cells. Those animals treated by inhalation were also examined for local damage in the lung. The assay for mutagens in the urine was negative as shown by the Ames assay with TA100 and TA98 and there was no increase in micronuclei or in metaphase aberrations. Histological sections from the animals treated by inhalation did not show the presence of particles, macrophage infiltrations and generalized lung damage. We tested the same fly ash with an in vitro cell transformation assay with the cell line Balb/c 3T3 subclone A31-1-13. Although there was not an increase in Type III foci, there was a dose-dependent increase of Type II foci in the treated cells over the controls. In one assay, there was approximately a 14-fold increase in Type II foci in the highest dose (2 mg/ml) compared to the solvent control. One other ash sample induced cell transformation without being markedly cytotoxic, while a third sample was highly toxic but did not induce transformation.

  6. Statistical Approach to the Transformation of Fly Ash into Zeolites

    NASA Astrophysics Data System (ADS)

    Derkowski, Arkadiusz; Michalik, Marek

    2007-01-01

    The experimental conversion of F-class fly ash into zeolites is described. The ash, composed mainly of aluminosilicate glass, mullite and quartz, was collected in the Cracow power plant (southern Poland). The experiments involved the heating of fly ash samples in PTFE vessels. Time, temperature and solution composition were the reaction parameters considered in the experiments and in the subsequent modeling. A series of reactions with 0.5, 3 and 5M NaOH solutions (and some with additional 3M NaCl) were carried out at 70°, 100° and 150°C for 12-48 hours under autogenic pressure (not measured) and at a constant ash-to-solution ratio of 33.3 g/l. The following zeolite phases were synthesized: sodalite (SOD structure), hydroxysodalite (SOD), CAN type phases, Na-X (FAU), and NaP1 (GIS). Statistically calculated relationships based on the mineral- and chemical compositions of the reaction products support the conclusion that the type of zeolite phase that crystallizes depends on the concentration of OH- and Cl- in solution and on the temperature of the reaction. The duration of reaction, if on the order of tens of hours, is of less significance. The nature of the zeolite phase that crystalises is controlled by the intensity and selectivity of the substrate dissolution. That dissolution can favour, in sequence, one or other of the components in the substrate, resulting in Si/Al variation in the reaction solutions. Mullite dissolution (decreasing solution Si/Al) characterizes the most advanced reaction stages. The sequence of crystallization of the zeolite phases mirrors the sequential dissolution of substrate components, and the composition of the crystallizing zeolite crystals reflects the changes in the solution Si/Al.

  7. Lime and fly ash stabilization of wastewater treatment sludge

    SciTech Connect

    Burns, H.; Gremminger, L.

    1994-01-11

    This invention provides a process meeting the EPA's PFRP standard for WWTS treatment thereby producing a readily usable end-product in either soil-like form or semi-impermeable low load bearing, mass form. The process includes mixing WWTS with lime and fly ash, to cause a temperature increase to above 70 C for at least 30 minutes and to cause the pH to exceed 12 for at least 2 hours. The end-product may be compacted to produce an semi-impermeable, durable mass or the soil-like product may be used as landfill cover material. 3 figs.

  8. Immobilization of cesium in alkaline activated fly ash matrix

    NASA Astrophysics Data System (ADS)

    Fernandez-Jimenez, A.; Macphee, D. E.; Lachowski, E. E.; Palomo, A.

    2005-11-01

    The immobilization potential of alkaline activated fly ash (AAFA) matrices for cesium has been investigated. The presence of Cs in the AAFA pastes, prepared using 8M NaOH solution as activator, showed no significant adverse effects on mechanical strength or microstructure, nor were significant quantities of Cs leached following application of the Toxic Characteristic Leaching Procedure (TCLP) and American Nuclear Society (ANS) 16.1 leaching protocols. Microstructural analysis shows Cs associated with the main reaction product in the AAFA suggesting that cesium is chemically bound rather than physically encapsulated. It is proposed that cesium is incorporated into the alkaline aluminosilicate gel, a precursor for zeolite formation.

  9. Combined glassification of EAF dust and incinerator fly ash.

    PubMed

    Cheng, T W

    2003-01-01

    Stainless steelmaking dust contains large amount of heavy metals, such as Cr and Ni. If these hazardous materials are not treated properly, they will cause detrimental secondary contamination. Preliminary study on recycling stainless steelmaking dust employed the thermal molten technology. Glass-ceramics were formed by combination stainless steel dust and incinerator fly ash with the ratio of 1:9. The major phases were Augite, Akermanite, and Donathite. It was found that the glass-ceramics shows the best characteristic at 900 degrees C after 5 h of heat treatment. This product can be used as building materials or refractory materials.

  10. High-volume fly ash utilization projects in the United States and Canada. Final report

    SciTech Connect

    Patelunas, G.M.

    1986-02-01

    The purpose of this report is to document existing high-volume applications of fly ash. Examples of high-volume projects are: backfills, embankments, fills, landfill cover, pavement base course, soil amendment, subgrade stabilization, grouts and hydraulic fills. Information was solicited from electric utilities, state highway agencies, ash marketers, engineering firms and other organizations in the United States and Canada. Over 270 separate projects that used fly ash in high-volume applications were identified. Class F fly ash was used in 172 projects, and Class C fly ash was used in 108 projects. The most frequent high-volume use of Class F fly ash was for fills, embankments and pavement base courses. These projects are primarily located in the north central and mid-Atlantic states. The most frequent use of Class C fly ash was for subgrade stabilization. Most of these projects are located in the midwestern and southwestern United States. The existence of many different applications of fly ash documented during this project demonstrates that fly ash is a practical high-volume construction material.

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

    PubMed

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

    2001-08-01

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

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

    SciTech Connect

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

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer Incinerator fly ash (IFA) is added to an alkali activated coal fly ash (CFA) matrix. Black-Right-Pointing-Pointer Means of stabilizing the incinerator ash for use in construction applications. Black-Right-Pointing-Pointer Concrete made from IFA, CFA and IFA-CFA mixes was chemically characterized. Black-Right-Pointing-Pointer Environmentally friendly solution to IFA disposal by reducing its toxicity levels. - Abstract: Municipal solid waste (MSW) incineration is a common and effective practice to reduce the volume of solid waste in urban areas. However, the byproduct of this process is a fly ash (IFA), which contains large quantities of toxic contaminants. The purpose of this research study was to analyze the chemical, physical and mechanical behaviors resulting from the gradual introduction of IFA to an alkaline activated coal fly ash (CFA) matrix, as a mean of stabilizing the incinerator ash for use in industrial construction applications, where human exposure potential is limited. IFA and CFA were analyzed via X-ray fluorescence (XRF), X-ray diffraction (XRD) and Inductive coupled plasma (ICP) to obtain a full chemical analysis of the samples, its crystallographic characteristics and a detailed count of the eight heavy metals contemplated in US Title 40 of the Code of Federal Regulations (40 CFR). The particle size distribution of IFA and CFA was also recorded. EPA's Toxicity Characteristic Leaching Procedure (TCLP) was followed to monitor the leachability of the contaminants before and after the activation. Also images obtained via Scanning Electron Microscopy (SEM), before and after the activation, are presented. Concrete made from IFA, CFA and IFA-CFA mixes was subjected to a full mechanical characterization; tests include compressive strength, flexural strength, elastic modulus, Poisson's ratio and setting time. The leachable heavy metal contents (except for Se) were below the maximum allowable limits and in many cases

  13. On the removal of hexavalent chromium from a Class F fly ash.

    PubMed

    Huggins, F E; Rezaee, M; Honaker, R Q; Hower, J C

    2016-05-01

    Coarse and fine samples of a Class F fly ash obtained from commercial combustion of Illinois bituminous coal have been exposed to two long-term leaching tests designed to simulate conditions in waste impoundments. ICP-AES analysis indicated that the coarse and fine fly ash samples contained 135 and 171mg/kg Cr, respectively. Measurements by XAFS spectroscopy showed that the ash samples originally contained 5 and 8% of the chromium, respectively, in the hexavalent oxidation state, Cr(VI). After exposure to water for more than four months, the percentage of chromium as Cr(VI) in the fly-ash decreased significantly for the coarse and fine fly-ash in both tests. Combining the XAFS data with ICP-AES data on the concentration of chromium in the leachates indicated that, after the nineteen-week-long, more aggressive, kinetic test on the coarse fly ash, approximately 60% of the Cr(VI) had been leached, 20% had been reduced to Cr(III) and retained in the ash, and 20% remained as Cr(VI) in the ash. In contrast, during the six-month-long baseline test, very little Cr was actually leached from either the coarse or the fine fly-ash (<0.1mg/kg); rather, about 66% and 20%, respectively, of the original Cr(VI) in the coarse and fine fly-ash was retained in the ash in that form, while the remainder, 34% and 80%, respectively, was reduced and retained in the ash as Cr(III). The results are interpreted as indicating that Cr(VI) present in Class F fly-ash can be reduced to Cr(III) when in contact with water and that such chemical reduction can compete with physical removal of Cr(VI) from the ash by aqueous leaching. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Fly ash mycorrhizoremediation through Paspalum scrobiculatum L., inoculated with Rhizophagus fasciculatus.

    PubMed

    Channabasava, Amareshappa; Lakshman, Huskur Chennarayappa; Muthukumar, Thangavelu

    2015-01-01

    Fly ash is the residue produced during the combustion of coal, and its disposal is a major environmental concern worldwide. However, fly ash can ameliorate soils by improving their physical, chemical, and biological properties. Hence, we conducted a study to understand the mycorrhizoremediation of different levels of fly ash (2%, 4%, and 6%) by using kodo millet (Paspalum scrobiculatum L.) inoculated with arbuscular mycorrhizal (AM) fungus Rhizophagus fasciculatus under greenhouse conditions. Fly ash amendment at a low level (2%) significantly enhanced AM colonization, spore number, plant growth, nutrient uptake, nutrient-use efficiencies and grain yield of kodo millet. Nevertheless, inoculation of soils amended with 2% fly ash with the AM fungus further enhanced the AM fungal, plant growth, nutrient uptake and yield parameters. Arbuscular mycorrhizal colonization decreased with increasing concentrations of fly ash amendment; however, such decrease was not linear. Our results also revealed a significantly higher plant growth, root/shoot ratios and nutrient contents in kodo millet shoots raised on 2% fly ash amendment and inoculated with the AM fungus at both harvests. Both fly ash amendment and AM fungus inoculation also significantly influenced the number of grains produced as well as the grain weight. Arbuscular mycorrhizal inoculation and fly ash amendment affected K, Ca, Mg, Na use efficiencies. Plant growth and nutrient parameters were strongly related to the extent of AM fungal colonization in the roots. These observations suggest that the inoculation of AM fungi along with low levels of fly ash amendment could be effectively used for the reclamation of low fertile or marginal soils and in turn fly ash could aid in crop production. Copyright © 2014 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  15. EFFECTS OF FLY ASH ON MERCURY OXIDATION DURING POST COMBUSTION CONDITIONS

    SciTech Connect

    Glenn A. Norton; Hongqun Yang; Robert C. Brown; Dennis L. Laudal; Grant E. Dunham; John Erjavec; Joseph M. Okoh

    2002-01-31

    Tests were performed in simulated flue gas streams using fly ash from the electrostatic precipitators of two full-scale utility boilers. One fly ash was from a Powder River Basin (PRB) coal, while the other was from Blacksville coal. Elemental Hg was injected upstream from samples of fly ash loaded onto filters housed in an oven at 120 or 180 C. Concentrations of oxidized and elemental Hg downstream from the filters were determined using the Ontario Hydro method. The gas stream composition and whether or not ash was present in the gas stream were the two most important variables affecting Hg oxidation. The presence of HCl, NO, NO{sub 2}, and SO{sub 2} were all important with respect to Hg oxidation, with NO{sub 2} and HCl being the most important. The presence of NO suppressed Hg oxidation in these tests. Although the two fly ashes were chemically and mineralogically diverse, there were generally no large differences in catalytic potential (for oxidizing Hg) between them. Similarly, no ash fraction appeared to be highly catalytic relative to other ash fractions. This includes fractions enriched in unburned carbon and fractions enriched in iron oxides. Although some differences of lesser magnitude were observed in the amount of oxidized Hg formed, levels of oxidized Hg generally tracked well with the surface areas of the different ashes and ash fractions. Therefore, although the Blacksville fly ash tended to show slightly more catalytic activity than the PRB fly ash, this could be due to the relatively high surface area of that ash. Similarly, for Blacksville fly ash, using nonmagnetic ash resulted in more Hg oxidation than using magnetic ash, but this again tracked well with the relative surface areas of the two ash fractions. Test results suggest that the gas matrix may be more important in Hg oxidation chemistry than the fly ash composition. Combustion tests were performed in which Blacksville and PRB fly ashes were injected into filtered (via a baghouse with

  16. Mechanical treatment of fly ashes. Part 2: Particle morphologies in ground fly ashes (GFA) and workability of GFA-cement mortars

    SciTech Connect

    Paya, J.; Monzo, J.; Borrachero, M.V.; Peris-Mora, E.; Gonzalez-Lopez, E.

    1996-02-01

    Mechanical treatment (by grinding) effects on particle morphology and specific gravity of fly ashes, and workability of ground fly ash (GFA) cement mortars have been studied. Different shape morphologies of GFA particles have been established: shell shaped and irregular solid fragments. Real and bulk specific gravity values were measured, proving that grinding process increased the content of poor shape particles. Particle Packing Factor (PPF) for GFA decreased below 50%. Workability of GFA-cement mortars is negatively affected. Good correlations between flow table spread (FTS) values per water volume unit and fly ash replacing percentage have been obtained, and a relative workability factor W{sub r} is established. Determination of W{sub r} value permits comparison of the effect of grinding or other fly ash processing methods on workability of mortars. Finally, good linear relationships between W{sub r} values and the inverse of mean diameter particle or calculated specific surface area were found.

  17. Characterization of Slag, Fly Ash and Portland Cement for Saltstone

    SciTech Connect

    Harbour, J

    2006-02-01

    Batch-to-batch variability in the chemical and physical properties of the fly ash, slag and portland cement (binders) will be an ongoing concern over the many years that salt waste from Tank 50 will be processed into grout at the Saltstone Processing Facility. This batch-to-batch variability in the properties of the binder materials translates to variability in the fresh and cured properties of Saltstone. Therefore, it is important to quantify the batch-to-batch variability of the binder materials and the resultant variation in grout properties. This report is the starting point for that process by providing the baseline (reference point) binder properties to which future batches of binder materials can be compared. For this characterization effort, properties of fly ash, slag and portland cement were obtained and documented in this report. These properties included particle size distribution by laser light scattering and dry sieving, particle size and morphology by scanning electron microscopy, true, aerated and tapped densities, chemical composition, rheological properties of the water based slurries made from individual binder material, and volatility through thermogravimetric analysis and differential thermal analysis. The properties presented in this report also provide a baseline data set to assist in problem solving efforts when or if unanticipated and/or unwanted processing events occur at the Saltstone Processing Facility.

  18. Flow injection analysis of MWC fly ash leaching characteristics

    SciTech Connect

    Willemin, J.A.; Nesbitt, C.C.; Dewey, G.R.; Sandall, J.F.; Sutter, L.L.

    1995-11-01

    A completely mixed batch reactor leaching method utilizing flow injection analysis (the CMBR-FIA method) was developed to study the lead leaching characteristics of municipal waste combustor fly ash. Flow injection analysis (FIA) coupled with atomic absorption spectrophotometry enabled the determination of lead concentrations at one minute intervals. The pH and oxidation-reduction potential of the solution were continuously monitored to characterize the leaching conditions. Automatic titration was used to alter the solution pH to defined endpoints. The CMBR-FIA method offers the ability to immediately observe alterations to the leaching solution, and grants the freedom to study a number of parameters concurrently. The CMBR-FIA method is a rapid and reliable means to investigate leaching characteristics. This paper describes the method and demonstrates its use to monitor the leaching of lead from municipal solid waste combustor fly ash as a function of pH. Soluble lead concentrations are shown to increase quickly with decreasing pH. A maximum of 50% of the total lead concentration was available in solution at pH 2. This value gradually decreased with time to over 35% of the total. 16 refs., 6 figs.

  19. Leachability and analytical speciation of antimony in coal fly ash.

    PubMed

    Miravet, Ricard; López-Sánchez, José Fermín; Rubio, Roser

    2006-08-25

    The present study assesses the single extraction of Sb from two coal fly ashes with aqueous solutions at a range of pHs (1-12) and with citrate 1 mol L(-1) at pH 5, in order to obtain preliminary information about Sb leaching from this matrix. Speciation analysis of the coal fly ash extracts by HPLC-ICP-MS and HPLC-HG-AFS was carried out in order to identify the presence of individual Sb species. Sb(V) was the main Sb species in the leachates, although minor amounts of Sb(III) were also detected in some extracts. Citrate at pH 5 gave the best extraction efficiency for both samples whereas Sb species were also fairly soluble in aqueous solutions at acidic pHs. Analysis by HPLC-ICP-MS provided the most accurate results in some extracts (aqueous solution at pH 1 and citrate at pH 5) when both coupled techniques used were compared. The presence in these leachates of higher content of interfering metal ions (Ca, Fe and Pb) than those obtained for the Sb species reduced stibine generation in the HPLC-HG-AFS analysis. The proposed methodology can be considered reliable and useful for antimony speciation in environmental studies.

  20. Strength properties of fly ash based controlled low strength materials.

    PubMed

    Türkel, S

    2007-08-25

    Controlled low strength material (CLSM) is a flowable mixture that can be used as a backfill material in place of compacted soils. Flowable fill requires no tamping or compaction to achieve its strength and typically has a load carrying capacity much higher than compacted soils, but it can still be excavated easily. The selection of CLSM type should be based on technical and economical considerations for specific applications. In this study, a mixture of high volume fly ash (FA), crushed limestone powder (filler) and a low percentage of pozzolana cement have been tried in different compositions. The amount of pozzolana cement was kept constant for all mixes as, 5% of fly ash weight. The amount of mixing water was chosen in order to provide optimum pumpability by determining the spreading ratio of CLSM mixtures using flow table method. The shear strength of the material is a measure of the materials ability to support imposed stresses on the material. The shear strength properties of CLSM mixtures have been investigated by a series of laboratory tests. The direct shear test procedure was applied for determining the strength parameters Phi (angle of shearing resistance) and C(h) (cohesion intercept) of the material. The test results indicated that CLSM mixtures have superior shear strength properties compared to compacted soils. Shear strength, cohesion intercept and angle of shearing resistance values of CLSM mixtures exceeded conventional soil materials' similar properties at 7 days. These parameters proved that CLSM mixtures are suitable materials for backfill applications.

  1. Examination of the system fly ash lime calcined gypsum water

    NASA Astrophysics Data System (ADS)

    Marinkovic, S.; Kostic-Pulek, A.

    2007-05-01

    The feasibility of the utilization of the system fly ash lime calcined gypsum (β-hemihydrate) water (the mass ratio 2:1:2:2.5) for the production of building ceramics was investigated. The system was cured under different conditions, i.e., tap water and ambient air. It was confirmed by X-ray diffraction analysis that three hydration products (gypsum, portlandite and ettringite) were formed in the water-cured system and two (gypsum and portlandite) in the air-cured system. Due to the formation of these products, a compressive strength of 4.01 MPa in the water-cured and 7.83 MPa in air-cured system developed. When the air-cured system was exposed to three alternate heating cooling or three alternate cooling heating cycles, the compressive strength increased (from 7.83 to 9.47 and 10.55 MPa, respectively). The fly ash lime calcined gypsum water systems prepared in this work can be applied for the manufacture of products for internal walls (bricks and blocks).

  2. Quantification of the degree of reaction of fly ash

    SciTech Connect

    Ben Haha, M.; De Weerdt, K.; Lothenbach, B.

    2010-11-15

    The quantification of the fly ash (FA) in FA blended cements is an important parameter to understand the effect of the fly ash on the hydration of OPC and on the microstructural development. The FA reaction in two different blended OPC-FA systems was studied using a selective dissolution technique based on EDTA/NaOH, diluted NaOH solution, the portlandite content and by backscattered electron image analysis. The amount of FA determined by selective dissolution using EDTA/NaOH is found to be associated with a significant possible error as different assumptions lead to large differences in the estimate of FA reacted. In addition, at longer hydration times, the reaction of the FA is underestimated by this method due to the presence of non-dissolved hydrates and MgO rich particles. The dissolution of FA in diluted NaOH solution agreed during the first days well with the dissolution as observed by image analysis. At 28 days and longer, the formation of hydrates in the diluted solutions leads to an underestimation. Image analysis appears to give consistent results and to be most reliable technique studied.

  3. Surface modification of purified fly ash and application in polymer.

    PubMed

    Yang, Yu-Fen; Gai, Guo-Sheng; Cai, Zhen-Fang; Chen, Qing-Ru

    2006-05-20

    With the growing general concern about the pollution by fly ash (FA), there has been global interest in its utilization. Purified FA or FA micro-beads are suitable as polymer filling materials because of their density, good dispersity and fluidity of globular particles. However, FA as a filler has not been widely used up to now on account of low whiteness values and low friction of untreated FA surface. In order to improve the FA quality, a surface modification method by using isothermal heating is proposed in this paper. Preparation of composite fly ash (CFA) in the Ca(OH)(2)-H(2)O-CO(2) system is described. Good coating results on FA surfaces can be achieved under suitable operating parameters. The characteristics of CFA are discussed and analyzed based on data from X-ray diffraction, scanning electron microscopy (SEM), infrared spectra, and BET multiple-point nitrogen adsorption method. Feedstocks with less than 45 microm grain size, 2.86 m(2) g(-1) specific surface area, and 36.68 whiteness value revealed an increase in specific surface area ranging from 8.69 to 10.01 m(2) g(-1) and an increase in whiteness values ranging from 63.67 to 73.13 after coating. A SEM study allowed a detailed determination of the morphology of the surface roughness. Filling tests also show that a rough surface of the CFA enhances contact opportunities and improves the interface between polymer and CFA blended with polypropylene (PP).

  4. Lead sorption performance on active silica derived from fly ash.

    PubMed

    Zhang, Xizhu; Zhu, Zhibao

    2015-01-01

    The object of this study was to estimate the sorption property of active silica derived from fly ash after separation of silica and aluminum. The specific surface area of active silica enlarged to 115 m(2)/g was compared with the original fly ash (4 m(2)/g). Field emission scanning electron microscopy displayed the active silica, which looked like a honeycomb or curly layer with many lamellae that formed many mesopores. The uptake kinetics indicated that the residual concentration of Pb(2+) in the aqueous solution decreased rapidly from the initial 1.25 mg/L to less than 10 μg/L within 45 min. The removal efficiency of Pb(2+) on active silica was pH dependent. The increase in pH value promoted Pb(2+) removal because the negative surface provided more electrostatic attraction sites. A stepwise non-linear isotherm was obtained because the lamellae of active silica provided a heterogeneous surface with various kinds of active sites. The maximum sorption amount of Pb on active silica was more than 90 mg/g, which was better than some pristine-activated carbon.

  5. Kinetics of fly ash beneficiation by carbon burnout. [Quarterly report], October 1, 1995--January 30, 1996

    SciTech Connect

    Dodoo, J.N.; Okoh, J.M.; Yilmaz, E.

    1996-09-01

    The objective is to investigate the kinetics of beneficiation of fly ash by carbon burnout. The three year project that was proposed is a joint venture between Delmarva Power, a power generating company on the eastern shore of Maryland, and the University of Maryland Eastern Shore. The studies have focused on the beneficiation of fly ash by carbon burnout. The increasing use of coal fly ash as pozzolanic material in Portland cement concrete means that there is the highest economic potential in marketability of large volumes of fly ash. For the concrete industry to consider large scale use the fly ash must be of the highest quality. This means that the residual carbon content of the fly ash must have an acceptable loss on ignition (LOI) value, usually between 7--2% residual carbon. The economic gains to be had from low-carbon ash is a fact that is generally accepted by the electricity generating companies. However, since the cost of producing low-carbon in large quantities, based on present technology, far outweighs any financial gains, no electrical power company using coal as its fuel at present considers the effort worthwhile. The concrete industry would use fly ash in cement concrete mix if it can be assured of its LOI value. At present no utility company would give such assurance. Hence with several million tons of fly ash produced by a single power plant per year all that can be done is to dump the fly ash in landfills. The kinetics of fly ash beneficiation have been investigated in the zone II kinetic regime, using a Cahn TG 121 microbalance in the temperature 550--750{degrees}C. The P{sub 02} and total surface area dependence of the reaction kinetics were determined using a vacuum accessory attached to the microbalance and a surface area analyzer (ASAP 2010), respectively.

  6. Speciation of Selenium, Arsenic, and Zinc in Class C Fly Ash

    SciTech Connect

    Luo, Yun; Giammar, Daniel E.; Huhmann, Brittany L.; Catalano, Jeffrey G.

    2011-11-17

    A major environmental concern associated with coal fly ash is the mobilization of trace elements that may contaminate water. To better evaluate proper use of fly ash, determine appropriate disposal methods, and monitor postdisposal conditions, it is important to understand the speciation of trace elements in fly ash and their possible environmental impact. The speciation of selenium, arsenic, and zinc was determined in five representative Class C fly ash samples from combustion of sub-bituminous Powder River Basin coal using synchrotron-based X-ray absorption spectroscopy to provide an improved understanding of the mechanisms of trace element association with the fly ash. Selenium in all fly ash samples occurs predominantly as Se(IV), with the exception of one sample, in which there was a minor amount of Se(0). Se(0) is likely associated with the high content of unburned coal in the sample. Arsenic exists in the fly ash as a single phase most consistent with calcium pyroarsenate. In contrast, zinc occurs as two distinct species in the silicate glass matrix of the fly ash. This work demonstrates that residual carbon in fly ash may reduce potential Se mobility in the environment by retaining it as less soluble elemental Se instead of Se(IV). Further, this work suggests that As and Zn in Class C fly ash will display substantially different release and mobilization behaviors in aquatic environments. While As release will primarily depend upon the dissolution and hydrolysis of calcium pyroarsenate, Zn release will be controlled by the dissolution of alkaline aluminosilicate glass in the ash.

  7. Permeation Properties and Pore Structure of Surface Layer of Fly Ash Concrete

    PubMed Central

    Liu, Jun; Qiu, Qiwen; Xing, Feng; Pan, Dong

    2014-01-01

    This paper presents an experimental study on the nature of permeation properties and pore structure of concrete surface layers containing fly ash. Concretes containing different dosages of fly ash as a replacement for cement (15% and 30% by weight of total cement materials, respectively) were investigated. Concrete without any fly ash added was also employed as the reference specimen. Laboratory tests were conducted to determine the surface layer properties of concrete including chloride transport, apparent water permeability and pore structure. The results demonstrate that incorporation of fly ash, for the early test period, promotes the chloride ingress at the surface layer of concrete but substituting proportions of fly ash may have little impact on it. With the process of chloride immersion, the chloride concentration at the surface layer of concrete with or without fly ash was found to be nearly the same. In addition, it is suggested that the water permeability at the concrete surface area is closely related to the fly ash contents as well as the chloride exposure time. Pore structure was characterized by means of mercury intrusion porosimetry (MIP) test and the scanning electron microscopy (SEM) images. The modification of pore structure of concrete submersed in distilled water is determined by the pozzolanic reaction of fly ash and the calcium leaching effect. The pozzolanic reaction was more dominant at the immersion time of 180 days while the calcium leaching effect became more evident after 270 days. PMID:28788677

  8. SPECIATION OF MERCURY IN THE PRESENCE OF COAL AND WASTE COMBUSTION FLY ASHES

    EPA Science Inventory

    The paper gives results of a study that focused on the oxidation of elemental mercury (Hgo) in the presence of both complex, four-component, model fly ashes, and actual coal combustion fly ashes collected from a pilot plant. Steady-state oxidation of Hgo promoted by the four-com...

  9. Research on the denitration mechanism of fly ash catalysts modified by low-temperature plasma technology

    NASA Astrophysics Data System (ADS)

    Nie, Wen-jie; Sha, Xiang-ling; Zhang, Lei; Wang, Yu-su; Wen, Xin; Li, Yong-hui

    2017-08-01

    There are three different fly ashes mixed with bentonite respectively as raw material to preparation of denitration catalyst. Then the catalyst combined with the low temperature plasma for denitration. The different mixing ratio, drying temperature and drying time of catalyst preparation were studied. The denitration mechanism of fly ash catalyst modified with different gases (O2, N2, Ar, and hydrocarbon gas) by low-temperature plasma technology was studied. The compositions of fly ash were detected by element analysis, ICP analysis, Boehm analysis, and Infrared spectral analysis which affected the denitration performance of fly ash catalyst. And we discussed the effect of denitration performance with different types of fly ash and plasma power. The results shown that: fly ash mixed with bentonite for 2:1, drying temperature is 100°C and drying time is 30 min are the optimal preparation conditions; The denitration performance is best of the catalyst which produced by circulating fluidized bed when the plasma power is 30 W. And Oxygen can be used as the modification gas for preparing the fly-ash catalyst. There are more basic functional groups on the surface of fly ash catalyst modified with oxygen atmosphere and the N=O plays a main role.

  10. Experimental study on durability improvement of fly ash concrete with durability improving admixture.

    PubMed

    Quan, Hong-zhu; Kasami, Hideo

    2014-01-01

    In order to improve the durability of fly ash concrete, a series of experimental studies are carried out, where durability improving admixture is used to reduce drying shrinkage and improve freezing-thawing resistance. The effects of durability improving admixture, air content, water-binder ratio, and fly ash replacement ratio on the performance of fly ash concrete are discussed in this paper. The results show that by using durability improving admixture in nonair-entraining fly ash concrete, the compressive strength of fly ash concrete can be improved by 10%-20%, and the drying shrinkage is reduced by 60%. Carbonation resistance of concrete is roughly proportional to water-cement ratio regardless of water-binder ratio and fly ash replacement ratio. For the specimens cured in air for 2 weeks, the freezing-thawing resistance is improved. In addition, by making use of durability improving admixture, it is easier to control the air content and make fly ash concrete into nonair-entraining one. The quality of fly ash concrete is thereby optimized.

  11. Kinetics of fly ash beneficiation by carbon burnout: Quarterly report, October 1-December 31, 1997

    SciTech Connect

    1997-12-31

    To investigate the kinetics of beneficiation of fly ash by carbon burnout The project is a joint venture between Delmarva Power, a power generating company on the eastern shore of Maryland, and the University of Maryland Eastern Shore. The studies have focused on the beneficiation of fly ash by carbon burnout.

  12. Stabilization of Oklahoma expensive soils using lime and class C fly ash

    SciTech Connect

    Buhler, R.L.; Cerato, A.B.

    2007-01-15

    This study uses lime and class C fly ash, an industrial byproduct of electric power production produced from burning lignite and subbituminous coal, to study the plasticity reduction in highly expensive natural clays from Idabel, Oklahoma. This study is important, especially in Oklahoma, because most of the native soils are expansive and cause seasonal damage to roadways and structures. The addition of lime or fly ash helps to arrest the shrinkage and swelling behavior of soil. Four soil samples with the same AASHTO classification were used in this study to show shrinkage variability within a soil group with the addition of lime and class C fly ash. The plasticity reduction in this study was quantified using the linear shrinkage test. It was found that soils classified within the same AASHTO group had varying shrinkage characteristics. It was also found that both lime and fly ash reduced the lienar shrinkage, however, the addition of lime reduced the linear shrinkage to a greater degree than the same percentage of class C fly ash. Even though it takes much less lime than fly ash to reduce the plasticity of a highly expansive soil, it may be less expensive to utilize fly ash, which is a waste product of electric power production. Lime also has a lower unit weight than fly ash so weight percentage results may be misleading.

  13. California bearing ratio behavior of soil-stabilized class F fly ash systems

    SciTech Connect

    Leelavathamma, B.; Mini, K.M.; Pandian, N.S.

    2005-11-01

    Fly ash is a finely divided mineral residue resulting from the combustion of coal in power plants that occupies large extents of land and also causes environmental problems. Hence, concerted attempts are being made to effectively use fly ash in an environmentally friendly way instead of dumping. Several studies have been carried out for its bulk utilization, such as its addition to improve the California bearing ratio (CBR) of soil in roads and embankments. But a thorough mixing of fly ash with soil may not be possible in the field. Hence a study has been carried out on the CBR behavior of black cotton soil and Raichur fly ash (which is class F) in layers and compared with the same in mixes. The results show that the CBR values of soil-fly ash mixes are better than layers, as expected. To improve the strength of layers, cement is used as an additive to fly ash. The results show that black cotton soil can be improved with stabilized fly ash, solving its strength problem as well as the disposal problem of fly ash.

  14. Adsorption-desorption of metolachlor and atrazine in Indian soils: effect of fly ash amendment.

    PubMed

    Ghosh, Rakesh K; Singh, Neera

    2013-02-01

    The effect of two fly ashes as soil amendment on the adsorption-desorption of metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylphenyl)] and atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) was studied in alluvial and laterite soils. The adsorption data for both the herbicides fitted well the Freundlich equation, and Freundlich adsorption coefficient (K (f)) increased with an increase of fly ash amount. Both the fly ashes differed in their extent to increase herbicide sorption, and the effect was different in different soils. Atrazine was sorbed more in the soils/soils + fly ash mixtures than the metolachlor. The K (f) values showed significant correlation with the amount of fly ash amendment (correlation coefficient, R > 0.982). The desorption isotherms also fitted the Freundlich equation, and desorption showed hysteresis which increased with an increase in the content of fly ash amendment. The free energy change (ΔG) indicated that the sorption process is exothermic, spontaneous, and physical in nature. The study has shown that fly ash as soil amendment significantly increased the sorption of metolachlor and atrazine, but the effect is soil- and fly ash-specific.

  15. Environmental-benign utilisation of fly ash as low-cost adsorbents.

    PubMed

    Wang, Shaobin; Wu, Hongwei

    2006-08-25

    Fly ash is a waste substance from thermal power plants, steel mills, etc. that is found in abundance in the world. In recent years, utilisation of fly ash has gained much attention in public and industry, which will help reduce the environmental burden and enhance economic benefit. In this paper, the technical feasibility of utilisation of fly ash as a low-cost adsorbent for various adsorption processes for removal of pollutants in air and water systems has been reviewed. Instead of using commercial activated carbon or zeolites, a lot of researches have been conducted using fly ash for adsorption of NO(x), SO(x), organic compounds, and mercury in air, and cations, anions, dyes and other organic matters in waters. It is recognised that fly ash is a promising adsorbent for removal of various pollutants. Chemical treatment of fly ash will make conversion of fly ash into a more efficient adsorbent for gas and water cleaning. Investigations also revealed that unburned carbon component in fly ash plays an important role in adsorption capacity. Directions for future research are also discussed.

  16. Influence Of Trace Metal Distribution On Its Leachability From Coal Fly Ash

    EPA Science Inventory

    The risks associated with the reuse of coal fly ash in natural environmental settings in terms of their mobility and ecotoxicological significance is largely determined by: (1) the physicochemical conditions the fly ash is placed under; (2) the total leachable metal content in fl...

  17. Experimental Study on Durability Improvement of Fly Ash Concrete with Durability Improving Admixture

    PubMed Central

    Quan, Hong-zhu; Kasami, Hideo

    2014-01-01

    In order to improve the durability of fly ash concrete, a series of experimental studies are carried out, where durability improving admixture is used to reduce drying shrinkage and improve freezing-thawing resistance. The effects of durability improving admixture, air content, water-binder ratio, and fly ash replacement ratio on the performance of fly ash concrete are discussed in this paper. The results show that by using durability improving admixture in nonair-entraining fly ash concrete, the compressive strength of fly ash concrete can be improved by 10%–20%, and the drying shrinkage is reduced by 60%. Carbonation resistance of concrete is roughly proportional to water-cement ratio regardless of water-binder ratio and fly ash replacement ratio. For the specimens cured in air for 2 weeks, the freezing-thawing resistance is improved. In addition, by making use of durability improving admixture, it is easier to control the air content and make fly ash concrete into nonair-entraining one. The quality of fly ash concrete is thereby optimized. PMID:25013870

  18. SPECIATION OF MERCURY IN THE PRESENCE OF COAL AND WASTE COMBUSTION FLY ASHES

    EPA Science Inventory

    The paper gives results of a study that focused on the oxidation of elemental mercury (Hgo) in the presence of both complex, four-component, model fly ashes, and actual coal combustion fly ashes collected from a pilot plant. Steady-state oxidation of Hgo promoted by the four-com...

  19. Permeation Properties and Pore Structure of Surface Layer of Fly Ash Concrete.

    PubMed

    Liu, Jun; Qiu, Qiwen; Xing, Feng; Pan, Dong

    2014-05-30

    This paper presents an experimental study on the nature of permeation properties and pore structure of concrete surface layers containing fly ash. Concretes containing different dosages of fly ash as a replacement for cement (15% and 30% by weight of total cement materials, respectively) were investigated. Concrete without any fly ash added was also employed as the reference specimen. Laboratory tests were conducted to determine the surface layer properties of concrete including chloride transport, apparent water permeability and pore structure. The results demonstrate that incorporation of fly ash, for the early test period, promotes the chloride ingress at the surface layer of concrete but substituting proportions of fly ash may have little impact on it. With the process of chloride immersion, the chloride concentration at the surface layer of concrete with or without fly ash was found to be nearly the same. In addition, it is suggested that the water permeability at the concrete surface area is closely related to the fly ash contents as well as the chloride exposure time. Pore structure was characterized by means of mercury intrusion porosimetry (MIP) test and the scanning electron microscopy (SEM) images. The modification of pore structure of concrete submersed in distilled water is determined by the pozzolanic reaction of fly ash and the calcium leaching effect. The pozzolanic reaction was more dominant at the immersion time of 180 days while the calcium leaching effect became more evident after 270 days.

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

    PubMed

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

    2015-09-01

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

  1. Influence Of Trace Metal Distribution On Its Leachability From Coal Fly Ash

    EPA Science Inventory

    The risks associated with the reuse of coal fly ash in natural environmental settings in terms of their mobility and ecotoxicological significance is largely determined by: (1) the physicochemical conditions the fly ash is placed under; (2) the total leachable metal content in fl...

  2. Fly-ash-amended sand as filter media in bioretention cells to improve phosphorus removal.

    PubMed

    Zhang, Wei; Brown, Glenn O; Storm, Daniel E; Zhang, Hailin

    2008-06-01

    This study identified material with high phosphorus sorption suitable for bioretention filter media. Materials examined were fly ash, two expanded shales, peat moss, limestone, and two common Oklahoma soils--Teller loam and Dougherty sand. The peat moss was a phosphorus source, while the two soils, limestone, and one expanded shale had only modest sorption capacity. One expanded shale and the fly ash had significant phosphorus sorption. Fly ash is unsuitable for use in a pure form, as a result of its low permeability, but phosphorus sorption on the sand was increased significantly with the incorporation of small amounts of fly ash. Column leaching experiments found that the sand with 2.5 and 5% fly ash and the better expanded shale had linear, non-equilibrium transport retardation factors of 272, 1618, and 185, with first-order rate coefficients of 0.153, 0.0752, and 0.113 hour(-1), respectively. Desorption experiments showed that the phosphorus sorption on the sand/fly ash mixture is largely nonreversible. Transport simulation assuming a 1-m-deep sand/fly ash treatment layer, with 5% of the watershed area, showed that the sand/fly ash filter media could effectively treat 1 mg/L influent for 12 years in a paved watershed and 34 years in a grassed watershed before exceeding Oklahoma's scenic rivers' phosphorus criterion of 0.037 mg/L. Significant phosphorus removal would continue for over 100 years.

  3. Effects of chemical composition of fly ash on efficiency of metal separation in ash-melting of municipal solid waste

    SciTech Connect

    Okada, Takashi; Tomikawa, Hiroki

    2013-03-15

    Highlights: ► Separation of Pb and Zn from Fe and Cu in ash-melting of municipal solid waste. ► Molar ratio of Cl to Na and K in fly ash affected the metal-separation efficiency. ► The low molar ratio and a non-oxidative atmosphere were better for the separation. - Abstract: In the process of metal separation by ash-melting, Fe and Cu in the incineration residue remain in the melting furnace as molten metal, whereas Pb and Zn in the residue are volatilized. This study investigated the effects of the chemical composition of incineration fly ash on the metal-separation efficiency of the ash-melting process. Incineration fly ash with different chemical compositions was melted with bottom ash in a lab-scale reactor, and the efficiency with which Pb and Zn were volatilized preventing the volatilization of Fe and Cu was evaluated. In addition, the behavior of these metals was simulated by thermodynamic equilibrium calculations. Depending on the exhaust gas treatment system used in the incinerator, the relationships among Na, K, and Cl concentrations in the incineration fly ash differed, which affected the efficiency of the metal separation. The amounts of Fe and Cu volatilized decreased by the decrease in the molar ratio of Cl to Na and K in the ash, promoting metal separation. The thermodynamic simulation predicted that the chlorination volatilization of Fe and Cu was prevented by the decrease in the molar ratio, as mentioned before. By melting incineration fly ash with the low molar ratio in a non-oxidative atmosphere, most of the Pb and Zn in the ash were volatilized leaving behind Fe and Cu.

  4. Relationship between textural properties, fly ash carbons, and Hg capture in fly ashes derived from the combustion of anthracitic pulverized feed blends

    SciTech Connect

    Isabel Surez-Ruiz; Jose B. Parra

    2007-08-15

    In this work, the textural properties of a series of whole anthracitic-derived fly ashes sampled in eight hoppers from the electrostatic precipitators and their sized fractions (from {gt}150 to {lt}25 {mu}m) are investigated. Data from N{sub 2} adsorption isotherms at 77 K, helium density, and mercury porosimetry have contributed to establish a relationship between the Brunauer-Emmett-Teller (BET) surface areas, VTOT, porosity, carbon content (the type of fly ash carbons), and Hg retention in these fly ashes. The unburned carbons in these ashes are macroporous materials, and they are different from the carbons in fly ashes from classes C and F (the latter derived from the combustion of bituminous coals) and show different textural properties. These ashes represent the end member of the fly ash classes C and F with respect to certain textural properties. Although the BET surface area and VTOT values for the studied samples are the lowest reported, they increase with the increase in carbon content, anisotropic carbon content, and particle size of the ashes. Thus, a positive relationship between all these parameters and Hg capture by the coarser ash fractions was found. The finest fraction of carbons ({lt}25 {mu}m) represented an exception. Although it makes a significant contribution to the total carbon of the whole fly ashes and shows relatively higher surface areas and VTOT values, its Hg concentration was found to be the lowest. This suggests that the type of unburned carbons in the finest fraction and/or other adsorption mechanisms may play a role in Hg concentration. Because the textural properties of anisotropic carbons depend on their subtype and on their origin, the need for its differentiation has been evidenced. 54 refs., 8 figs., 3 tabs.

  5. Possible Use of Fly Ash in Ceramic Industries: AN Innovative Method to Reduce Environmental Pollution

    NASA Astrophysics Data System (ADS)

    Sharma, Gayatri; Mehla, S. K.; Bhatnagar, Tarun; Bajaj, Annu

    The process of coal combustion results in coal ash, 80% of which is very fine in nature & is thus known as fly ash. Presently, in India, about 120 coal based thermal power plants are producing about 90-120 million tons of fly ash every year. With increase in demand of power energy, more and more thermal power plants are expected to commission in near future and it is expected that fly ash generation will be 225 million tons by 2017. Disposal of fly ash requires large quantity of land, water and energy and its fine particles, if not disposed properly, by virtue of their weightless, can become air born and adversely affect the entire Environment. These earth elements primarily consist of silica, alumina & iron etc. and its physicochemical parameters are closely resembles with volcanic ash, natural soil etc. These properties, therefore, makes it suitable for use in ceramic industries and helps in saving the environment and resources.

  6. Treatment and toxicity evaluation of methylene blue using electrochemical oxidation, fly ash adsorption and combined electrochemical oxidation-fly ash adsorption.

    PubMed

    Wang, Kai-sung; Wei, Ming-Chi; Peng, Tzu-Huan; Li, Heng-Ching; Chao, Shu-Ju; Hsu, Tzu-Fang; Lee, Hong-Shen; Chang, Shih-Hsien

    2010-08-01

    Treatment of a basic dye, methylene blue, by electrochemical oxidation, fly ash adsorption, and combined electrochemical oxidation-fly ash adsorption was compared. Methylene blue at 100 mgL(-1) was used in this study. The toxicity was also monitored by the Vibrio fischeri light inhibition test. When electrochemical oxidation was used, 99% color and 84% COD were removed from the methylene blue solution in 20 min at a current density of 428 Am(-2), NaCl of 1000 mgL(-1), and pH(0) of 7. However, the decolorized solution showed high toxicity (100% light inhibition). For fly ash adsorption, a high dose of fly ash (>20,000 mgL(-1)) was needed to remove methylene blue, and the Freundlich isotherm described the adsorption behavior well. In the combined electrochemical oxidation-fly ash adsorption treatment, the addition of 4000 mgL(-1) fly ash effectively reduced intermediate toxicity and decreased the COD of the electrochemical oxidation-treated methylene blue solution. The results indicated that the combined process effectively removed color, COD, and intermediate toxicity of the methylene blue solution.

  7. Fly ash as replacement for cement in extruded fiber-reinforced cement composites

    SciTech Connect

    Peled, A.; Akkaya, Y.; Shah, S.P.

    1999-11-01

    The objective of this work was to develop extrudable compositions of fiber-reinforced cement composites that contain high content of fly ash. For that purpose specimens containing different ratio of fly ash as replacement for cement were extruded, with different fiber types: acrylic, PVA, glass and cellulose. Composites produced with the conventional cast process were also examined for comparison. It was found that fly ash improves the flexural strength and ductility of the extruded composite compared to composites without fly ash, for all fiber types. In the cast composites fly ash improved the composite ductility but reduced the flexural strength of the composite. Differences in matrix properties and fiber-matrix interface between the cast and extrusion composites can explain the differences in the flexural performances.

  8. Effects of fly ash inhalation on murine immune function: effects on systemic response

    SciTech Connect

    Eskew, M.L.; Zarkower, A.; Scheuchenzuber, W.J.; Graham, J.A.

    1982-08-01

    Mice were exposed to fly ash at levels ranging from 728-2221 ..mu..g/m/sup 3/ respirable for varying periods of time, and several immunological parameters were measured. Little change was noted in splenic response to mitogens or cytolytic ability. Splenic lymphocytes from fly ash-exposed mice incorporated significantly more thymidine following subcutaneous sensitization with BCG, although no differences were noted in response of these lymphocytes to PPD. Fly ash exposure of greater than 1 week caused a suppression of antibody response to aerosols of Escherichia coli in the spleen, but not in the mediastinal lymph nodes. Following 3-4 weeks of fly ash exposure, no changes in splenic antibody responses were noted following intravenous injections of LPS or intratracheal injections of DNP-Ficoll. However, after 9 months exposure at higher concentrations of fly ash, splenic plaque-forming responses were significantly suppressed after both aerosol and intratracheal exposure to antigen.

  9. Research and industrialization progress of recovering alumina from fly ash: A concise review.

    PubMed

    Ding, Jian; Ma, Shuhua; Shen, Shirley; Xie, Zongli; Zheng, Shili; Zhang, Yi

    2017-02-01

    Fly ash, a by-product of high temperature combustion of coal in coal-fired power plants, is one of the most complex and largest amount of industrial solid wastes generated in China. Its improper disposal has become an environmental problem. Now it is widely realized that fly ash should be considered as a useful and potential mineral resource. Fly ash is rich in alumina, making it a potential substitute for bauxite. With the diminishing reserves of bauxite resources, as well as the increasing demand for alumina, recovery of alumina from fly ash has attracted extensive attention world-wide. The present review describes, firstly, the generation and physicochemical properties of high alumina fly ash found in northern China and then focuses on the various alumina recovery technologies, the advantages and disadvantages of these processes, and in particular, the latest industrial developments. Finally, the directions for future research are also considered. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Use of rubber and bentonite added fly ash as a liner material.

    PubMed

    Cokca, Erdal; Yilmaz, Zeka

    2004-01-01

    In many countries regulations require all hazardous waste disposal facilities to be lined with suitable impermeable barriers to protect against contamination. In this study, a series of laboratory tests on rubber and bentonite added fly ash were conducted. The aim of the tests was to evaluate the feasibility of utilizing fly ash, rubber and bentonite as a low hydraulic conductivity liner material. Type C fly ash was obtained from Soma thermal power plant in Turkey; rubber in pulverized form was waste from the retreading industry. To investigate the properties of rubber and bentonite added fly ash, hydraulic conductivity, leachate analysis, unconfined compression, split tensile strength, one-dimensional consolidation, swell and freeze/thaw cycle tests were performed. The overall evaluation of results have revealed that rubber and bentonite added fly ash showed good promise and a candidate for construction of a liner.

  11. Influence of alkali cation on the mechanical properties and durability of fly ash based geopolymers.

    PubMed

    Nikolić, Irena; Zejak, Radomir; Jankovič-Častvan, Ivona; Karanović, Ljiljana; Radmilović, Vuk; Radmilović, Velimir

    2013-01-01

    This research has provided information about the influence of alkali cations (Na+ and K+) on the mechanical properties and durability of fly ash based geopolymers. The results have shown that alkali cations have a strong influence on the mechanical properties of fly ash based geopolymers. K-geopolymers generally reach a higher value of compressive strength in comparison to Na- geopolymers. On the other hand, microstructure and phase composition of fly ash based geopolymers are not influenced by the nature of alkali cations. The ratio of main gel structure forming elements is practically not affected by the nature of alkali cations. Durability of fly ash based geopolymers in different aquatic environments is greatly dependent on the choice of alkali cations. Na- geopolymers are generally more resistant in water and aggressive environments than the K-geopolymers. The best durability of fly ash based geopolymers was observed in sea water.

  12. Use of rubber and bentonite added fly ash as a liner material

    SciTech Connect

    Cokca, Erdal; Yilmaz, Zeka

    2004-07-01

    In many countries regulations require all hazardous waste disposal facilities to be lined with suitable impermeable barriers to protect against contamination. In this study, a series of laboratory tests on rubber and bentonite added fly ash were conducted. The aim of the tests was to evaluate the feasibility of utilizing fly ash, rubber and bentonite as a low hydraulic conductivity liner material. Type C fly ash was obtained from Soma thermal power plant in Turkey; rubber in pulverized form was waste from the retreading industry. To investigate the properties of rubber and bentonite added fly ash, hydraulic conductivity, leachate analysis, unconfined compression, split tensile strength, one-dimensional consolidation, swell and freeze/thaw cycle tests were performed. The overall evaluation of results have revealed that rubber and bentonite added fly ash showed good promise and a candidate for construction of a liner.

  13. Process for making ferrite spherical particulate toner core from raw fly ash

    SciTech Connect

    Aldrich, R.G.; Earl, G.H.; Trunko, D.W.

    1987-10-06

    This patent describes a process for making a ferrite spherical particulate toner carrier core from raw fly ash obtained from burning coal comprising (a) recovering the magnetic particles from the non-magnetic particles of the raw fly ash; (b) selecting a desired size for the particles of the raw fly ash and screening the fly ash to obtain the desired sized particles; and (c) purifying the raw fly ash treated according to steps (a) and (b) to obtain a ferrite composition having a particle size from 20-300 microns, in which the particles are essentially spherical, having an apparent density of at least 1.8 g/cm/sup 3/; a saturation magnetization of 43-70 emu/g; a remanence of 5 emu/g or less; a Hall Flow of 20 sec. or greater/50 g.

  14. Process for making ferrite spherical particulate toner core from raw fly ash

    SciTech Connect

    Aldrich, R.G.; Earl, G.H.; Trunko, D.W.

    1991-09-10

    This patent describes a process for making a ferrite spherical particulate toner carrier core from raw fly ash obtained from burning coal. It comprises recovering the magnetic particles from the non-magnetic particles of the raw fly ash: selecting a desired size for the particles of the raw fly ash and screening the fly ash to obtain the desired sized particles; and purifying the raw fly ash treated to obtain a ferrite composition having a particle size from 20-300 microns, in which the particles are essentially spherical, having an apparent density of at least 1.8 g/cm{sup 3}; a saturation magnetization of 43-70 emu/g; a remanence of 5 emu/g or less; a Hall Flow of 20 sec. or greater/50 g.

  15. Alkaline hydrothermal conversion of fly ash filtrates into zeolites 2: utilization in wastewater treatment.

    PubMed

    Somerset, Vernon; Petrik, Leslie; Iwuoha, Emmanuel

    2005-01-01

    Filtrates were collected using a codisposal reaction wherein fly ash was reacted with acid mine drainage. These codisposal filtrates were then analyzed by X-ray Fluorescence spectrometry for quantitative determination of the SiO2 and Al2O3 content. Alkaline hydrothermal zeolite synthesis was then applied to the filtrates to convert the fly ash material into zeolites. The zeolites formed under the experimental conditions were faujasite, sodalite, and zeolite A. The use of the fly ash-derived zeolites and a commercial zeolite was explored in wastewater decontamination experiments as it was applied to acid mine drainage in different dosages. The concentrations of Ni, Zn, Cd, As, and Pb metal ions in the treated wastewater were investigated. The results of the treatment of the acid mine drainage with the prepared fly ash zeolites showed that the concentrations of Ni, Zn, Cd, and Hg were decreased as the zeolite dosages of the fly ash zeolite (FAZ1) increased.

  16. Influence of curing temperature on cement hydration and mechanical strength development of fly ash mortars

    SciTech Connect

    Maltais, Y.; Marchand, J.

    1997-07-01

    The influence of fly ash and curing temperature on cement hydration and compressive strength development of mortars was investigated. Test parameters included type of fly ash (two different Class F fly ashes were tested), the level of cement replacement (10, 20 and 30% by mass), and curing temperature (20 C and 40 C). The mortar physical and microstructural properties were determined by means of thermal analyses, compressive strength measurements and SEM observations. Test results confirm that fly ash tends to increase significantly the rate of cement hydration at early age. Data also demonstrate that an elevation of the curing temperature reduces the long-term compressive strength of the reference mortar mixture. In contrast, an increase of the curing temperature seems to have no detrimental effect on the long-term compressive strength of the fly ash mixtures.

  17. Application of large volume injection GC-MS to analysis of organic compounds in the extracts and leachates of municipal solid waste incineration fly ash.

    PubMed

    Korenková, Eva; Matisová, Eva; Slobodník, Jaroslav

    2006-01-01

    Organic solvent and water extracts of fly ash from a Milan (Italy) municipal solid waste incinerator (MSWI) were analyzed by large volume injection-gas chromatography-mass spectrometry (LVI-GC-MS) with programmable temperature vaporizer (PTV). Using injection volumes of 10-100 microl, typically over a hundred compounds were detected in organic solvent extracts and ca. 35% of them could be tentatively identified from their electron impact ionization mass spectra. A protocol for the determination of the maximum amount of a potential environmental pollutant available for leaching (availability test) was developed for four selected target compounds: pentachlorobenzene (PeCB), hexachlorobenzene (HxCB), o-terphenyl (o-TPH) and m-terphenyl (m-TPH). Key parameters, extraction time and liquid-to-solid ratio (L/S), were studied in more detail. Recoveries of PeCB, HxCB and o-TPH spiked into the fly ash samples at two concentration levels ranged from 38% to 53% for freshly spiked and from 14% to 40% for 40-day aged fly ash. Recoveries of m-TPH were 8% to 11% from freshly spiked and less than 3% from aged spiked fly ash. The native amounts in Milan MSWI fly ash, determined in an interlaboratory exercise using the developed protocol, were 31 ng/g PeCB, 34 ng/g HxCB, 72 ng/g o-TPH and 4.4 ng/g m-TPH. A separate methodology was developed for the determination of compounds extracted from fly ash by water (leaching test). Following 8-h sonication at L/S 20, the leached amounts of PeCB, HxCB and o-TPH were 1.1, 3.1 and 6.0 ng/g fly ash, respectively.

  18. Application of large volume injection GC-MS to analysis of organic compounds in the extracts and leachates of municipal solid waste incineration fly ash

    SciTech Connect

    Korenkova, Eva; Slobodnik, Jaroslav

    2006-07-01

    Organic solvent and water extracts of fly ash from a Milan (Italy) municipal solid waste incinerator (MSWI) were analyzed by large volume injection-gas chromatography-mass spectrometry (LVI-GC-MS) with programmable temperature vaporizer (PTV). Using injection volumes of 10-100 {mu}l, typically over a hundred compounds were detected in organic solvent extracts and ca. 35% of them could be tentatively identified from their electron impact ionization mass spectra. A protocol for the determination of the maximum amount of a potential environmental pollutant available for leaching (availability test) was developed for four selected target compounds: pentachlorobenzene (PeCB), hexachlorobenzene (HxCB), o-terphenyl (o-TPH) and m-terphenyl (m-TPH). Key parameters, extraction time and liquid-to-solid ratio (L/S), were studied in more detail. Recoveries of PeCB, HxCB and o-TPH spiked into the fly ash samples at two concentration levels ranged from 38% to 53% for freshly spiked and from 14% to 40% for 40-day aged fly ash. Recoveries of m-TPH were 8% to 11% from freshly spiked and less than 3% from aged spiked fly ash. The native amounts in Milan MSWI fly ash, determined in an interlaboratory exercise using the developed protocol, were 31 ng/g PeCB, 34 ng/g HxCB, 72 ng/g o-TPH and 4.4 ng/g m-TPH. A separate methodology was developed for the determination of compounds extracted from fly ash by water (leaching test). Following 8-h sonication at L/S 20, the leached amounts of PeCB, HxCB and o-TPH were 1.1, 3.1 and 6.0 ng/g fly ash, respectively.

  19. Power plant fly ash as a resource for alumina and cement

    SciTech Connect

    Murtha, M.J.; Burnet, G.

    1980-01-01

    A sinter process has been developed to form soluble aluminate compounds from mixtures of fly ash, limestone, and soda ash. The aluminates are extracted, treated to remove silicates, and precipitated; the precipitate is calcined to metallurgical grade alumina. The extract residue shows promise as a raw material for the production of Portland cement. Process economics are presented, and the effects of alumina and silica contents of the fly ash, sintering temperatures and time, and sales credits for by-products are discussed.

  20. Effect of fly ash amendment on metolachlor and atrazine degradation and microbial activity in two soils.

    PubMed

    Ghosh, Rakesh Kumar; Singh, Neera; Singh, Shashi Bala

    2016-08-01

    The study reports the effect of Inderprastha (IP) and Badarpur (BP) fly ashes on degradation of metolachlor and atrazine in Inceptisol and Alfisol soils. Metolachlor dissipated at faster rate in Alfisol (t1/2 8.2-8.6 days) than in Inceptisol (t1/2 13.2-14.3 days). The fly ashes enhanced the persistence of metolachlor in both the soils; however, the extent of effect was more in Inceptisol (t1/2 16.6-33.8 days) than Alfisol (t1/2 8.4-12 days) and effect increased with fly ash dose. 2-Ethyl-6-methylacetanilide was detected as the only metabolite of metolachlor. Atrazine was more persistent in flooded soils (t1/2 10.8-20.3 days) than nonflooded soils (t1/2 3.7-12.6 days) and fly ash increased its persistence, but effect was more pronounced in the flooded Inceptisol (t1/2 23.7-31 days) and nonflooded Alfisol (t1/2 6.3-10.1 days). Increased herbicide sorption in the fly ash-amended soils might have contributed to the increased pesticide persistence. The IP fly ash inhibited microbial biomass carbon at 5 % amendment levels in both the soils, while BP fly ash slightly increased microbial biomass carbon (MBC) content. Dehydrogenase activity was inhibited by both fly ashes in both the soils with maximum inhibition observed in the IP fly ash-amended Alfisol. No significant effect of fly ash amendment was observed on the fluorescein diacetate activity.

  1. Gypsum treated fly ash as a liner for waste disposal facilities

    SciTech Connect

    Sivapullaiah, Puvvadi V.; Baig, M. Arif Ali

    2011-02-15

    Fly ash has potential application in the construction of base liners for waste containment facilities. While most of the fly ashes improve in the strength with curing, the ranges of permeabilities they attain may often not meet the basic requirement of a liner material. An attempt has been made in the present context to reduce the hydraulic conductivity by adding lime content up to 10% to two selected samples of class F fly ashes. The use of gypsum, which is known to accelerate the unconfined compressive strength by increasing the lime reactivity, has been investigated in further improving the hydraulic conductivity. Hydraulic conductivities of the compacted specimens have been determined in the laboratory using the falling head method. It has been observed that the addition of gypsum reduces the hydraulic conductivity of the lime treated fly ashes. The reduction in the hydraulic conductivity of the samples containing gypsum is significantly more for samples with high amounts of lime contents (as high as 1000 times) than those fly ashes with lower amounts of lime. However there is a relatively more increase in the strengths of the samples with the inclusion of gypsum to the fly ashes at lower lime contents. This is due to the fact that excess lime added to fly ash is not effectively converted into pozzolanic compounds. Even the presence of gypsum is observed not to activate these reactions with excess lime. On the other hand the higher amount of lime in the presence of sulphate is observed to produce more cementitious compounds which block the pores in the fly ash. The consequent reduction in the hydraulic conductivity of fly ash would be beneficial in reducing the leachability of trace elements present in the fly ash when used as a base liner.

  2. Use of fly ash in diets of cage and floor broilers

    SciTech Connect

    Pharr, C.L.; Andrews, L.D.

    1980-09-01

    Three experiments were conducted to compare limestone to fly ash from a coal-fired generator station as a calcium source for broilers. In experiment 1, 5 male and 5 female broiler chicks were placed in each of 32 cages. Sixteen cages of birds were fed a ration with limestone supplying 30% of the total calcium and 16 cages were fed a ration with 30% of the total calcium supplied by fly ash. The total calcium and phosphorus levels of the rations were 1.0% and .5%, respectively. In this experiment no significant difference was found for 8-week body weight between diets where the added calcium was from limestone or fly ash. In experiment 2 a group of 40 male and 40 female cage reared broilers and 40 male and 40 female floor reared broilers were fed a basal diet of limestone providing 33% of the total calcium. Three diets with increasing fly ash levels were fed to three cage groups of 40 male and 40 female broilers providing 33, 46, and 45% of the total calcium of .9, 1.1, and 1.8%, respectively. Broilers fed the highest fly ash level weighed significantly less at 8 weeks than the caged controls but did not differ from the other treatments. Bone breaking strength as measured by the Allo Kramer Shear Press was similar between the basal and low level fly ash group and increased with higher fly ash levels. In experiment 3 four groups of 40 male broilers in cages were fed limestone diets with graded levels of limestone for the calcium source. Another four groups of 40 caged male broilers were fed fly ash diets with equivalent graded levels of fly ash for the calcium source. Both limestone and fly ash diets provided .17, .34, .51, and .68% calcium of a total calcium content of .28, .45, .62, and .79%, respectively.

  3. Fly ash application in nutrient poor agriculture soils: impact on methanotrophs population dynamics and paddy yields.

    PubMed

    Singh, Jay Shankar; Pandey, Vimal Chandra

    2013-03-01

    There are reports that the application of fly ash, compost and press mud or a combination thereof, improves plant growth, soil microbial communities etc. Also, fly ash in combination with farmyard manure or other organic amendments improves soil physico-chemical characteristics, rice yield and microbial processes in paddy fields. However, the knowledge about the impact of fly ash inputs alone or in combination with other organic amendments on soil methanotrophs number in paddy soils is almost lacking. We hypothesized that fly ash application at lower doses in paddy agriculture soil could be a potential amendment to elevate the paddy yields and methanotrophs number. Here we demonstrate the impact of fly ash and press mud inputs on number of methanotrophs, antioxidants, antioxidative enzymatic activities and paddy yields at agriculture farm. The impact of amendments was significant for methanotrophs number, heavy metal concentration, antioxidant contents, antioxidant enzymatic activities and paddy yields. A negative correlation was existed between higher doses of fly ash-treatments and methanotrophs number (R(2)=0.833). The content of antioxidants and enzymatic activities in leaves of higher doses fly ash-treated rice plants increased in response to stresses due to heavy metal toxicity, which was negatively correlated with rice grain yield (R(2)=0.944) and paddy straw yield (R(2)=0.934). A positive correlation was noted between heavy metals concentrations and different antioxidant and enzymatic activities across different fly ash treated plots.The data of this study indicate that heavy metal toxicity of fly ash may cause oxidative stress in the paddy crop and the antioxidants and related enzymes could play a defensive role against phytotoxic damages. We concluded that fly ash at lower doses with press mud seems to offer the potential amendments to improving soil methanotrophs population and paddy crop yields for the nutrient poor agriculture soils.

  4. Characterization of fly ash from a circulating fluidized bed incinerator of municipal solid waste.

    PubMed

    Zhang, Lin; Su, Xiaowen; Zhang, Zhixuan; Liu, Siming; Xiao, Yuxin; Sun, Mingming; Su, Jixin

    2014-11-01

    Treatment and disposal of fly ash in China are becoming increasingly difficult, since its production has steadily risen and its features are uncertain. The excess pollutant components of fly ash are the key factor affecting its treatment and resource utilization. In this study, fly ash samples collected from a power plant with circulating fluidized incinerators of municipal solid waste (MSW) located in Shandong Province (eastern China) were studied. The results showed that there were no obvious seasonal differences in properties of fly ash. The content of total salt, Zn, and pH exceeded the national standards and low-ring polycyclic aromatic hydrocarbons (PAHs) and polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (Fs) were the main organic components of fly ash for this power plant, which posed great threats to the surrounding environment. The amount of Zn of fly ash was higher than other heavy metals, which should be due to alkaline batteries of MSW. The leachate of fly ash had low concentrations of heavy metals and the main soluble components were sulfates and chlorides. The major mineral crystals of fly ash were SiO2, CaSO4, and Fe2O3. The main organic pollutants were low-ring PAHs, polychlorinated PCDDs, and low-chlorinated PCDFs, and concentrations were lower than the limiting values of the national regulations. Additionally, the distribution of PCDD/Fs had either a positive or a negative linear correlation with fly ash and flue gas, which was associated with the chlorinated degree of PCDD/Fs. The analysis was conducted to fully understand the properties of fly ash and to take appropriate methods for further comprehensive utilization.

  5. Gypsum treated fly ash as a liner for waste disposal facilities.

    PubMed

    Sivapullaiah, Puvvadi V; Baig, M Arif Ali

    2011-02-01

    Fly ash has potential application in the construction of base liners for waste containment facilities. While most of the fly ashes improve in the strength with curing, the ranges of permeabilities they attain may often not meet the basic requirement of a liner material. An attempt has been made in the present context to reduce the hydraulic conductivity by adding lime content up to 10% to two selected samples of class F fly ashes. The use of gypsum, which is known to accelerate the unconfined compressive strength by increasing the lime reactivity, has been investigated in further improving the hydraulic conductivity. Hydraulic conductivities of the compacted specimens have been determined in the laboratory using the falling head method. It has been observed that the addition of gypsum reduces the hydraulic conductivity of the lime treated fly ashes. The reduction in the hydraulic conductivity of the samples containing gypsum is significantly more for samples with high amounts of lime contents (as high as 1000 times) than those fly ashes with lower amounts of lime. However there is a relatively more increase in the strengths of the samples with the inclusion of gypsum to the fly ashes at lower lime contents. This is due to the fact that excess lime added to fly ash is not effectively converted into pozzolanic compounds. Even the presence of gypsum is observed not to activate these reactions with excess lime. On the other hand the higher amount of lime in the presence of sulphate is observed to produce more cementitious compounds which block the pores in the fly ash. The consequent reduction in the hydraulic conductivity of fly ash would be beneficial in reducing the leachability of trace elements present in the fly ash when used as a base liner. Copyright © 2010 Elsevier Ltd. All rights reserved.

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

    PubMed

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

    2016-06-07

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

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

    SciTech Connect

    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.

    2009-01-15

    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.

  8. Investigation on the utilization of coal fly ash as amendment to compost for vegetation in acid soil

    SciTech Connect

    Menon, M.P.

    1990-04-16

    The use of fly ash as amendment to compost is presented. Plant growth/yields of corn collard greens, mustard greens, and sorgum is described. The treatment parameters such as fly ash to compost ratio, fly ash-amended compost to soil ratio, type of compost used for treatment etc. are discussed. 2 refs., 5 figs., 8 tabs. (CBS)

  9. Sorption and chemical transformation of PAHs on coal fly ash. Technical progress report No. 8

    SciTech Connect

    Mamantov, G.; Wehry, E.L.

    1993-12-01

    The objective of this work is to characterize the interactions of coal fly ash with polycyclic aromatic hydrocarbons (PAHs) and their derivatives, and to understand the influence of the surface properties of coal ash (and other atmospheric particles) on the chemical transformations of polycyclic aromatic compounds. Specific investigations directed toward this overall objective include: (a) Fractionation of heterogeneous coal fly ash samples into different particle types varying in size and chemical composition (carbonaceous, mineral-magnetic, and mineral nonmagnetic); (b) Measurement of the rates of chemical transformation of PAHs and PAH derivatives (especially nitro-PAHs) and the manner in which the rates of such processes are influenced by the chemical and physical properties of coal fly ash particles; (c) Chromatographic and spectroscopic studies of the nature of the interactions of coal fly ash particles with PAHs and PAH derivatives; (d) Characterization of the fractal nature of fly ash particles (via surface area measurements) and the relationships of {open_quotes}surface roughness{close_quotes} of fly ash particles to the chemical behavior of PAHs sorbed on coal ash particles. PAHs are deposited, under controlled laboratory conditions, onto coal ash surfaces from the vapor phase, in order to mimic the processes by which PAHs are deposited onto particulate matter in the atmosphere.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  11. Site-specific study on stabilization of acid-generating mine tailings using coal fly ash

    SciTech Connect

    Shang, J.Q.; Wang, H.L.; Kovac, V.; Fyfe, J.

    2006-03-15

    A site-specific study on stabilizing acid-generating mine tailings from Sudbury Mine using a coal fly ash from Nanticoke Generating Station is presented in this paper. The objective of the study is to evaluate the feasibility of codisposal of the fly ash and mine tailings to reduce environmental impacts of Sudbury tailings disposal sites. The study includes three phases, i.e., characterization of the mine tailings, and coal fly ash, oxidation tests on the mine tailings and kinetic column permeation tests. The results of the experiments indicate that when permeated with acid mine drainage, the hydraulic conductivity of Nanticoke coal fly ash decreased more than three orders of magnitude (from 1 x 10{sup -6} to 1 x 10{sup -9} cm/s), mainly due to chemical reactions between the ash solids and acid mine drainage. Furthermore, the hydraulic gradient required for acid mine drainage to break through the coal fly ash is increased up to ten times (from 17 to 150) as compared with that for water. The results also show that the leachate from coal fly ash neutralizes the acidic pore fluid of mine tailings. The concentrations of trace elements in effluents from all kinetic column permeation tests indicated that coplacement of coal fly ash with mine tailings has the benefit of immobilizing trace elements, especially heavy metals. All regulated element concentrations from effluent during testing are well below the leachate quality criteria set by the local regulatory authority.

  12. The role of weathering on fly ash charge distribution during triboelectrostatic beneficiation.

    PubMed

    Cangialosi, Federico; Notarnicola, Michele; Liberti, Lorenzo; Stencel, John

    2009-05-30

    Triboelectrostatic beneficiation of coal combustion fly ashes with high-unburned carbon contents can produce low-carbon ash products having value as mineral admixtures and meeting technical requirements for replacing cement in concrete. This capability is a result of establishing bipolar charge on mineral ash versus carbon particles where, typically, unburned carbon attains positive surface charge and ash attains negative surface charge under the tribocharging conditions employed in triboelectrostatic technologies. However, long-term exposure of fly ash to weathering conditions, such as moisture or high humidity, before beneficiation is known to dramatically diminish carbon-ash separation efficiencies. Although experimentation has shown that water soluble surface species can be redistributed on fly ash particles after exposure to moisture, which could affect the extent of charging and polarities, measurement of the actual amount of charge and polarity on particles after weathering exposure versus after removal of surface moisture has not been accomplished. Hence, a new experimental methodology was developed and applied to measure charge distributions on tribocharged ash and carbon particles in a fly ash that had been exposed to weathering conditions for 6 months before and after removal of the surface moisture. Weathered ash particles were found to have an average zero charge, whereas carbon particles attained an average negative charge, opposite of the normal polarity for carbon. Although the extent of uncharged particles decreased and ash particles attained an average negative charge after drying, carbon particles attained only an average zero charge. These changes were reflected in very small increases in carbon-ash separation efficiency, in contrast to previous beneficiation tests in which fly ash drying led to significant increases in carbon-ash separation efficiency. It is suggested that removal of surface moisture in the absence of other processes like

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

    PubMed Central

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

    2014-01-01

    Coal fly ash with the addition of Al2O3 was recycled to produce mullite/alumina composites and the camphene-based freeze casting technique was processed to develop a controlled porous structure with improved mechanical strength. Many rod-shaped mullite crystals, formed by the mullitization of coal fly ash in the presence of enough silicate, melt. After sintering at 1300–1500 °C with the initial solid loadings of 30–50 wt.%, interconnected macro-sized pore channels with nearly circular-shaped cross-sections developed along the macroscopic solidification direction of camphene solvent used in freeze casting and a few micron-sized pores formed in the walls of the pore channels. The macro-pore size of the mullite/alumina composites was in the range 20–25 μm, 18–20 μm and 15–17 μm with reverse dependence on the sintering temperature at 30, 40 and 50 wt.% solid loading, respectively. By increasing initial solid loading and the sintering temperature, the sintered porosity was reduced from 79.8% to 31.2%, resulting in an increase in the compressive strength from 8.2 to 80.4 MPa. PMID:28788172

  14. Kinetics of fly ash beneficiation by carbon burnout. Quarterly report, January--March 1996

    SciTech Connect

    Dodoo, J.N.; Okoh, J.M.; Yilmaz, E.

    1996-09-01

    The three year project that was proposed is a joint venture between Delmarva Power, a power generating company on the eastern shore of Maryland, and the University of Maryland Eastern Shore. The studies have focused on the benefication of fly ash by carbon burnout. The increasing use of coal fly ash as pozzolanic material in Portland cement concrete means that there is the highest economic potential in marketability of large volumes of fly ash. For the concrete industry to consider large scale use the fly ash must be of the highest quality. This means that the residual carbon content of the fly ash must have an acceptable loss on ignition (LOI) value, usually between 7-2% residual carbon. The economic gains to be had from low-carbon ash is a fact that is generally accepted by the electricity generating companies. However, since the cost of producing low-carbon in large quantities, based on present technology, far outweighs any financial gains, no electrical power company using coal as its fuel at present considers the effort worthwhile. The concrete industry would use fly ash in cement concrete mix if it can be assured of its LOI value. At present no utility company would give such assurance. Hence with several million tons of fly ash produced by a single power plant per year all that can be done is to dump the fly ash in landfills. The kinetics of fly ash benefication have been investigated in the zone II kinetic regime, using a Cahn TG 121 microbalance in the temperature 550-750{degrees}C. The P{sub O{sub 2}} and total surface area dependence of the reaction kinetics were determined using a vacuum accessory attached to the microbalance and a surface area analyzer (ASAP 2010), respectively. 16 refs., 7 figs., 3 tabs.

  15. Design and Characterization of Renewable Bioasphalt Containing Damar Resin, Fly Ash, Wasted Cooking Oil and Latex

    NASA Astrophysics Data System (ADS)

    Setyawan, A.; Djumari; Legowo, S. J.; Widiharjo, B.; Zai, A. K. S.; Pradana, A. A. W.; Rusadi, I. P.; Permana, A.

    2017-02-01

    Dasphalt is one alternative of bioasphalt, made from materials that can be renewed as a substitute for conventional asphalt. Dasphalt inspired from jabung made of damar resin, brick powder and wasted cooking oil. Jabung have the same character with conventional asphalt. Research has been conducted by the characteristics of jabung but there are still many shortcomings, softening point and ductility values are not qualify. In this research the brick powder will be replaced by fly ash, as fly ash has a finer grain so that it can become a better absorbent. The resin will act as a natural resin for dasphalt, wasted cooking oil will be a mixed solvent. Use of additional polymers latex, is expected to improve the elasticity of dasphalt in ductility test. The purpose of this study was to determine the nature of the modification dasphalt properties in accordance with the specifications of asphalt penetration test and find the optimal composition of dasphalt. This research method is done by direct testing in the laboratory. In the present study that became the basic composition of the resin is resin (100g pure resin+ 350g resin packaging or powder), fly ash (150g) and wasted cooking oil (205g) and latex were mixed at temperatures below 150°C. While variations of latex starting from 0%, 2%, 4%, 6%, 8% and 10%. Several asphalt characterization are performed include penetration tests, test softening point, ductility test, flash point test, specific gravity test, affinity test and solubility test. Dasphalt modification achieved optimum composition of resin (100g pure resin or resin chunk + 350Gr packaging), Fly Ash powder (150g), cooking oil (205g), and latex 4%, ductility increased from 63.5 cm to 119.5 cm, the value of the flash point was originally at temperature of 240°C to 260°C, dasphalt penetration from 68.2 dmm to 43 dmm, and the value of density decreases to 1.01 g/cm3 to 0.99 g/cm3. Dasphalt modifications meet some of the specifications and could be categorized as

  16. Use of solid residue from thermal power plant (fly ash) for enhancing sewage sludge anaerobic digestion: Influence of fly ash particle size.

    PubMed

    Montalvo, S; Cahn, I; Borja, R; Huiliñir, C; Guerrero, L

    2017-11-01

    The influence of fly ash particle size on methane production and anaerobic biodegradability was evaluated. Assays with different fly ash particle sizes (0.8-2.36mm) at a concentration of 50mg/L were ran under mesophilic conditions. In anaerobic processes operating with fly ash, greater removal of both volatile total and suspended solids, chemical oxygen demand (total and soluble) was achieved, with an increase of methane production between 28% and 96% compared to the control reactors. The highest increase occurred at ash particles sizes of 1.0-1.4mm. The metal concentrations in the digestates obtained after anaerobic digestion of sewage sludge are far below those considered as limiting for the use of sludge in soils. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. EFFECTS OF FLY ASH ON MERCURY OXIDATION DURING POST COMBUSTION CONDITIONS

    SciTech Connect

    Unknown

    2000-10-01

    Tests were performed in simulated flue gas streams using two fly ash samples from the electrostatic precipitators of two full-scale utility boilers. One fly ash was derived from a Powder River Basin (PRB) coal, while the other was derived from Blacksville coal (Pittsburgh No. 8 seam). The tests were performed at temperatures of 120 and 180 C under different gas compositions using whole fly ash samples as well as magnetic and nonmagnetic concentrates from sized fly ash. Only the Blacksville ash contained magnetic phases. The whole and fractionated fly ash samples were analyzed for morphology, chemical composition, mineralogical composition, total organic carbon, porosity, and surface area. Mineralogically, the Blacksville ash was composed predominantly of magnetite, hematite, quartz, and mullite, while the PRB ash contained mostly quartz with lesser amounts of lime, periclase, and calcium aluminum oxide. The iron oxides in the Blacksville ash were concentrated almost entirely in the largest size fraction. As anticipated, there was not a clean separation of magnetic (Fe-rich) and nonmagnetic (aluminosilicate-rich) phases for the Blacksville ash. The Blacksville ash had a significantly higher surface area and a much higher unburned carbon content than the PRB ash. Elemental mercury (Hg) streams were injected into the simulated flue gas and passed over filters (housed in a convection oven) loaded with fly ash. Concentrations of total, oxidized, and elemental Hg downstream from the ash samples were determined by the Ontario Hydro Method. The gas stream composition and whether or not ash was present in the gas stream were the two most important variables. Based on the statistical analyses, the presence of HCl, NO, NO{sub 2}, and SO{sub 2} and all two-way gas interactions were significant. In addition, it appears that even four-factor interactions between those gases are significant. The HCl, NO{sub 2}, and SO{sub 2} were critical gases resulting in Hg oxidation, while

  18. Preferential removal and immobilization of stable and radioactive cesium in contaminated fly ash with nanometallic Ca/CaO methanol suspension.

    PubMed

    Mallampati, Srinivasa Reddy; Mitoma, Yoshiharu; Okuda, Tetsuji; Sakita, Shogo; Simion, Cristian

    2014-08-30

    In this work, the capability of nanometallic Ca/CaO methanol suspension in removing and/or immobilizing stable ((133)Cs) and radioactive cesium species ((134)Cs and (137)Cs) in contaminated fly ash was investigated. After a first methanol and second water washing yielded only 45% of (133)Cs removal. While, after a first methanol washing, the second solvent with nanometallic Ca/CaO methanol suspension yielded simultaneous enhanced removal and immobilization about 99% of (133)Cs. SEM-EDS analysis revealed that the mass percent of detectable (133)Cs on the fly ash surface recorded a 100% decrease. When real radioactive cesium contaminated fly ash (containing an initial 14,040Bqkg(-1)(134)Cs and (137)Cs cumulated concentration) obtained from burning wastes from Fukushima were reduced to 3583Bqkg(-1) after treatment with nanometallic Ca/CaO methanol suspension. Elution test conducted on the treated fly ash gave 100BqL(-1) total (134)Cs and (137)Cs concentrations in eluted solution. Furthermore, both ash content and eluted solution concentrations of (134)Cs and (137)Cs were much lower than the Japanese Ministry of the Environment regulatory limit of 8000Bqkg(-1) and 150BqL(-1) respectively. The results of this study suggest that the nanometallic Ca/CaO methanol suspension is a highly potential amendment for the remediation of radioactive cesium-contaminated fly ash.

  19. Hydrometallurgical recovery of germanium from coal gasification fly ash: pilot plant scale evaluation

    SciTech Connect

    Arroyo, F.; Fernandez-Pereira, C.; Olivares, J.; Coca, P.

    2009-04-15

    In this article, a hydrometallurgical method for the selective recovery of germanium from fly ash (FA) has been tested at pilot plant scale. The pilot plant flowsheet comprised a first stage of water leaching of FA, and a subsequent selective recovery of the germanium from the leachate by solvent extraction method. The solvent extraction method was based on Ge complexation with catechol in an aqueous solution followed by the extraction of the Ge-catechol complex (Ge(C{sub 6}H{sub 4}O{sub 2}){sub 3}{sup 2-}) with an extracting organic reagent (trioctylamine) diluted in an organic solvent (kerosene), followed by the subsequent stripping of the organic extract. The process has been tested on a FA generated in an integrated gasification with combined cycle (IGCC) process. The paper describes the designed 5 kg/h pilot plant and the tests performed on it. Under the operational conditions tested, approximately 50% of germanium could be recovered from FA after a water extraction at room temperature. Regarding the solvent extraction method, the best operational conditions for obtaining a concentrated germanium-bearing solution practically free of impurities were as follows: extraction time equal to 20 min; aqueous phase/organic phase volumetric ratio equal to 5; stripping with 1 M NaOH, stripping time equal to 30 min, and stripping phase/organic phase volumetric ratio equal to 5. 95% of germanium were recovered from water leachates using those conditions.

  20. Characteristics of SCC with Fly Ash and Manufactured Sand

    NASA Astrophysics Data System (ADS)

    Praveen Kumar, K.; Radhakrishna

    2016-09-01

    Self compacting concrete (SCC) of M40 grade was designed. The binder in SCC consists of OPC and fly ash in the ratio of 65:35. River sand was replaced by manufactured sand (M-sand) at replacement levels of 20,40,60,80 and 100%. An attempt was made to evaluate the workability and strength characteristics of self compacting concrete with river sand and manufactured sand as fine aggregates. For each replacement level, constant workability was maintained by varying the dosage of superplasticizer. T50 flow time, V Funnel time, V-funnel T5 time as well as compressive, split tensile and flexural strength of SCC were found at each replacement level of M-sand. They were compared to SCC with river sand. Results indicate favourable use of M-sand in preparation of Self Compacting Concrete.

  1. Phytoremediation efficiency of Eichhornia crassipes in fly ash pond.

    PubMed

    Pandey, Vimal Chandra

    2016-01-01

    The present study was focused on field research to examine the phytoremediation potential of naturally grown Eichhornia crassipes in fly ash (FA) pond. Field results indicate the efficiency of E. crassipes for remediation of heavy metals from FA pond. The bioconcentration factor trend was Cr (3.75) > Cu (2.62) > Cd (1.05), and Cu (1.35) in root and stem, respectively. The survival and abundance growth of E. crassipes in the circumstance of heavy metal enriched FA pond is another highlight of the present research that reveals its toxitolerant characteristics. Thus, this lesson on phytoremediation proved that E. crassipes is a potential accumulator of Cu, Cr, and Cd from FA ponds and is a promising species for FA pond's remediation globally.

  2. Glass-ceramic frits from fly ash in terracotta production.

    PubMed

    Karamanova, Emilia; Karamanov, Alexander

    2009-02-01

    Preliminary results of an investigation into the possible use of glass-ceramic frits from fly ash and glass cullet in terracotta (stoneware) tile manufacture are reported. Two new ceramics were studied and compared with a plant composition, containing 45 wt.% sodium feldspar. In the first ceramic batch 20% of the feldspar was substituted by frits and in the second the whole amount of feldspar was eliminated and replaced by 35% frits and 10% refractory waste. It was found that the addition of low viscous glass-ceramic frits decreased the sintering temperature by 50-100 degrees C. At the same time, due to formation of an additional crystal phase (i.e. pyroxene or anorthite) the new ceramics showed an improvement of 25-50% in bending strength.

  3. Determination of organic compounds leached from municipal incinerator fly ash by water at different pH levels

    SciTech Connect

    Karasek, F.W.; Charbonneau, G.M.; Reuel, G.J.; Tong, H.Y.

    1987-04-01

    This study concerns the possibility of organic compounds entering the environment through the leaching of municipal incinerator fly ash with water. A Soxhlet extraction of fly ash with water, followed by a benzene/water solvent extraction was used to isolate organic compounds. The pH of the extracting liquid was varied (pH 4, 7, 10) and both the type and amount of compounds extracted differed. Many organic compounds including polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, polycyclic aromatic compounds, phenols, and hydrocarbons were found in the water extracts. Gas chromatography/flame ionization detection, gas chromatography/electron capture detection, and gas chromatography/mass spectrometry using electron impact, positive and negative ion chemical ionization techniques were used for compound identification and quantitation.

  4. Chemical composition and physical properties of filter fly ashes from eight grate-fired biomass combustion plants.

    PubMed

    Lanzerstorfer, Christof

    2015-04-01

    For the handling, treatment and utilization of fly ash from biomass combustion its chemical composition and physical properties are important. In this study eight filter fly ashes from different grate-fired biomass combustion plants were investigated. In fly ash from straw combustion high concentrations of (K) were found, whereas in the fly ash from wood combustion the concentrations of Ca and Mg were higher. The average concentration of PO4(3-) was similar in both types of fly ashes. In all wood fly ashes some measured heavy metal concentrations were above the limits for utilization. The straw fly ashes were much less contaminated and can be utilized. For wood fly ash most parameters showed little variation, except from one fly ash where the dust pre-separator is in poor condition. The average values were: mass median diameter 4.3±0.8 μm, spread of particle size distribution 19±11, particle density 2620±80 kg/m3 and angle of repose 50°±1°. The density of the straw fly ashes is lower (2260±80 kg/m3) and the spread of the size distribution is higher (72±24). For one straw combustion fly ash the values of the mass median diameter and the angle of repose were similar to the values of wood combustion fly ash, for the other straw fly ash the values differed considerably. While the particle size of this fly ash was much smaller, surprisingly the angle of repose was also lower. This can be attributed to the formation of small agglomerates in this fly ash, which were not disintegrated without a certain stress.

  5. Mobility of heavy metals from coal fly ash

    NASA Astrophysics Data System (ADS)

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

    1994-06-01

    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.

  6. Leaching behavior of lime-fly ash mixtures

    SciTech Connect

    Daniels, J.L.; Das, G.P.

    2006-01-15

    As part of a larger investigation that included numerical and field-based components, the use of lime to reduce the leachability of a coal combustion fly ash was evaluated in the laboratory. The focus of this paper is on the experimental assessment of lime-fly ash leachability through sequential leach (SL), freeze-thaw (FT), and wet-dry (WD) leaching as well as multileachant sequential extraction (SE) tests. The results suggest that lime addition reduces the leachability for Cd, Se, and to some extent As. They also suggest that Cr is rendered more leachable with increasing lime content, for the conditions and low levels tested. It appears that there is a threshold lime content ({gt} 1.0%) that must be exceeded prior to reducing the leachability of As and Se. In particular, this threshold likely corresponds to the level at which appreciable cementitious reactions have developed. For example, in the case of As after the first cycle of leaching, the concentration was below the reporting limit (10 {mu} g/L) for 0% lime. However, at 0.5% lime amendment, the leached concentration increased to nearly 50 {mu} g/L. Subsequent lime additions reduced this concentration. No such threshold was observed for Cd leachability as was expected as a direct consequence of hydroxide precipitation, which is well established under the measured pH conditions. As such, Cd mobility is insensitive to the extent to which cementitious reactions are initiated. Overall, the results suggest that while lime stabilization may be effective for reducing leachability, sufficient amounts must be added; otherwise, the leachability of some constituents can actually be exacerbated.

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

    PubMed

    Kalaw, Martin Ernesto; Culaba, Alvin; Hinode, Hirofumi; Kurniawan, Winarto; Gallardo, Susan; Promentilla, Michael Angelo

    2016-07-15

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

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

    PubMed Central

    Kalaw, Martin Ernesto; Culaba, Alvin; Hinode, Hirofumi; Kurniawan, Winarto; Gallardo, Susan; Promentilla, Michael Angelo

    2016-01-01

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

  9. Advanced research and technology: Direct utilization recovery of minerals from coal fly ash. Fossil energy program

    NASA Astrophysics Data System (ADS)

    Burnet, G.; Murtha, M. J.; Adelman, D. J.

    1980-12-01

    Methods for utilizing coal fly ash through processes for the extraction of alumina and titania, and for the separation and use of an iron-rich fraction are described. Research of the HiChlor process for the extraction of alumina and titania by high temperature chlorination of a fly ash reductant mixture is described. An engineering cost evaluation is presented for a centralized HiChlor processing facility to process the fly ash of several large coal fueled power stations. Investigations for a high temperature lime soda process for extraction of alumina from fly ash included the use of several types of quarry limestones and waste materials to replace the limestone and/or soda ash.

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

    PubMed

    Chakraborty, Rajarshi; Mukherjee, Anita

    2011-02-01

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

  11. Fly ash from cellulose industry as secondary raw material in autoclaved aerated concrete

    SciTech Connect

    Hauser, A.; Eggenberger, U.; Mumenthaler, T.

    1999-03-01

    Because fly ash from cellulose industries contains considerable amounts of free lime and sulfate, they are potential secondary raw materials for the production of autoclaved aerated concrete. Laboratory experiments were performed by replacing lime and sulfate in conventional autoclaved aerated concrete mixtures by fly ash. Compared to a reference series, samples with even higher compressive strength could be produced with lime-sulfate ash. At higher proportions of fly ash, the formation of calcium silicate hydrate phases is delayed and the presence of unreacted portlandite and newly formed scawtite produce a drop in strength and an increase in shrinkage. Low strength resulted by using Al-bearing ash with a lower amount of free CaO, which makes this type of ash not applicable in practice.

  12. Mechanical and Durability Properties of Fly Ash Based Concrete Exposed to Marine Environment

    NASA Astrophysics Data System (ADS)

    Kagadgar, Sarfaraz Ahmed; Saha, Suman; Rajasekaran, C.

    2017-06-01

    Efforts over the past few years for improving the performance of concrete suggest that cement replacement with mineral admixtures can enhance the strength and durability of concrete. Feasibility of producing good quality concrete by using alccofine and fly ash replacements is investigated and also the potential benefits from their incorporation were looked into. In this study, an attempt has been made to assess the performance of concrete in severe marine conditions exposed upto a period of 150 days. This work investigates the influence of alccofine and fly ash as partial replacement of cement in various percentages (Alccofine - 5% replacement to cement content) and (fly ash - 0%, 15%, 30%, 50% & 60% to total cementitious content) on mechanical and durability properties (Permit ion permeability test and corrosion current density) of concrete. Usage of alccofine and high quantity of fly ash as additional cementitious materials in concrete has resulted in higher workability of concrete. Inclusion of alccofine shows an early strength gaining property whereas fly ash results in gaining strength at later stage. Concrete mixes containing 5% alccofine with 15% fly ash replacement reported greater compressive strength than the other concrete mixes cured in both curing conditions. Durability test conducted at 56 and 150 days indicated that concrete containing higher percentages of fly ash resulted in lower permeability as well lesser corrosion density.

  13. Suppression of phosphate liberation from eutrophic lake sediment by using fly ash and ordinary Portland cement

    SciTech Connect

    Heng-Peng Ye; Fan-Zhong Chen; Yan-Qing Sheng; Guo-Ying Sheng; Jia-Mo Fu

    2006-08-15

    In this study, the effect of suppression on phosphate liberation from eutrophic lake sediment by using fly ash and ordinary Portland cement (OPC) was investigated by small scale experiment. A system including sediment, lake water, and several kinds of capping materials was designed to clarify the suppression of phosphate liberation from sediment under the anaerobic condition. The suppression efficiencies of fly ash, OPC and glass bead used as control material were also determined, and these effects were discussed. The suppression efficiency of glass bead was 44.4%, and those of fly ash and OPC were 84.4%, 94.9%, respectively. The suppression by fly ash and OPC was mainly carried out by the adsorption effect, in addition to the covering effect. The suppression efficiency depended on the amounts of the material used, and about 90% of liberated phosphate was suppressed by fly ash of 10.0 Kg m{sup -2}, and OPC of 6.0 Kg m{sup -2}. The concentrations of heavy metals, such as mercury, cadmium, lead, copper, zinc, chromium, silver, arsenic and nickel, in fly ash and OPC were lower than those in the environmental materials. And it was considered that the concentrations of heavy metals in fly ash and OPC were too low to influence the ecosystem in natural water region.

  14. Recycling of municipal solid waste incinerator fly ash by using hydrocyclone separation.

    PubMed

    Ko, Ming-Sheng; Chen, Ying-Liang; Wei, Pei-Shou

    2013-03-01

    The municipal solid waste incinerators (MSWIs) in Taiwan generate about 300,000 tons of fly ash annually, which is mainly composed of calcium and silicon compounds, and has the potential for recycling. However, some heavy metals are present in the MSWI fly ash, and before recycling, they need to be removed or reduced to make the fly ash non-hazardous. Accordingly, the purpose of this study was to use a hydrocyclone for the separation of the components of the MSWI fly ash in order to obtain the recyclable portion. The results show that chloride salts can be removed from the fly ash during the hydrocyclone separation process. The presence of a dense medium (quartz sand in this study) is not only helpful for the removal of the salts, but also for the separation of the fly ash particles. After the dense-medium hydrocyclone separation process, heavy metals including Pb and Zn were concentrated in the fine particles so that the rest of the fly ash contained less heavy metal and became both non-hazardous and recyclable.

  15. Investigation of the uptake ability of fly ashes produced after lignite combustion.

    PubMed

    Kantiranis, N; Filippidis, A; Georgakopoulos, A

    2005-07-01

    Fly ash samples from the five steam electric power stations of the Lignite Center of Western Macedonia were used in this study. They consisted mainly of anhydrite, lime, quartz and amorphous material as well as feldspars, calcite, micas + clays, portlandite and gehlenite which were all present in minor amounts. Anhydrite, lime and portlandite in the fly ash samples diminished upon treatment with ammonium acetate aqueous solution, whereas quartz, feldspars, gehlenite and amorphous material were enriched. The uptake ability of the fly ash samples ranged from 89 to 101 mequ./100g. The uptake ability of the samples was mainly attributed to the amorphous material and the microporous minerals, micas + clays. The amorphous material content was estimated at between 17 and 20 wt% in the treated fly ashes and may be unburned organic matter and amorphous inorganic material that resulted during the combustion of the lignite. A positive correlation was observed between the uptake ability and the total percentage of amorphous material and micas + clays. The relatively high uptake ability of the fly ash samples could lead to additional industrial and environmental uses of the fly ashes. The environmental advantage of fly ash exploitation will be particularly important for large electric power centers, such as the LCWM.

  16. A pilot study of mercury liberation and capture from coal-fired power plant fly ash.

    PubMed

    Li, Jin; Gao, Xiaobing; Goeckner, Bryna; Kollakowsky, Dave; Ramme, Bruce

    2005-03-01

    The coal-fired electric utility generation industry has been identified as the largest anthropogenic source of mercury (Hg) emissions in the United States. One of the promising techniques for Hg removal from flue gas is activated carbon injection (ACI). The aim of this project was to liberate Hg bound to fly ash and activated carbon after ACI and provide high-quality coal combustion products for use in construction materials. Both bench- and pilot-scale tests were conducted to liberate Hg using a thermal desorption process. The results indicated that up to 90% of the Hg could be liberated from the fly ash or fly-ash-and-activated-carbon mixture using a pilot-scale apparatus (air slide) at 538 degrees C with a very short retention time (less than 1 min). Scanning electron microscope (SEM) evaluation indicated no significant change in fly ash carbon particle morphology following the thermal treatment. Fly ash particles collected in the baghouse of the pilot-scale apparatus were smaller in size than those collected at the exit of the air slide. A similar trend was observed in carbon particles separated from the fly ash using froth flotation. The results of this study suggest a means for power plants to reduce the level of Hg in coal-combustion products and potentially recycle activated carbon while maintaining the resale value of fly ash. This technology is in the process of being patented.

  17. Use of fly-ash for sealing a radioactive waste repository

    SciTech Connect

    Ollagnier, M.; Tauziede, C.; Olivier, J.

    1993-12-31

    The mining industry currently uses fly-ash from coal-fired power-plants to close access shafts in abandoned mines, in sedimentary formations. The technique consists of installing a plug of fly-ash, about fifty meters high, at the base of the shaft-lining. In this study, fly-ash is considered as a possible sealant for radioactive repositories in sedimentary formations, as well as in hard rock. Specific studies have been conducted in order to assess the feasibility of this technique, and to improve the long-term performance of the fly-ash seals. The hydraulic and mechanical characteristics of fly-ash, taken from the plug of an abandoned shaft, as well as from dumps of various ages, were measured. Laboratory tests showed that it is possible to reduce the hydraulic conductivity of fly-ash by a factor of thousand, with the addition of ten percent bentonite. Moreover, it seems possible to block fine fissures in the surrounding damaged rock by injecting grouts made of cement and fly-ash having maximum diameters of twenty micrometers.

  18. Removal of carbon constituents from hospital solid waste incinerator fly ash by column flotation.

    PubMed

    Liu, Hanqiao; Wei, Guoxia; Zhang, Rui

    2013-01-01

    Hospital solid waste incinerator (HSWI) fly ash contains a large number of carbon constituents including powder activated carbon and unburned carbon, which are the major source of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in fly ash. Therefore, the removal of carbon constituents could reduce PCDD/Fs in fly ash greatly. In this study, the effects of the main flotation parameters on the removal of carbon constituents were investigated, and the characteristics of the final product were evaluated. The results showed that loss on ignition (LOI) of fly ash increased from 11.1% to 31.6% during conditioning process. By optimizing the flotation parameters at slurry concentration 0.05 kg/l, kerosene dosage 12 kg/t, frother dosage 3 kg/t and air flow rate 0.06 m(3)/h, 92.7% of the carbon constituents were removed from the raw fly ash. Under these conditions, the froth product has LOI of 56.35% and calorific values of 12.5 MJ/kg, LOI in the tailings was below 5%, and the total toxic equivalent (TEQ) of PCDD/Fs decreased from 5.61 ng-TEQ/g in the raw fly ash to 1.47 ng-TEQ/g in the tailings. The results show that column flotation is a potential technology for simultaneous separation of carbon constituents and PCDD/Fs from HSWI fly ash.

  19. Removal of unburned carbon from municipal solid waste fly ash by column flotation.

    PubMed

    Huang, Ying; Takaoka, Masaki; Takeda, Nobuo

    2003-01-01

    Unburned carbon (UC) is the major source of organic contaminants in municipal solid waste (MSW) fly ash. So most organic contaminants can be removed by the removal of the UC from the MSW fly ash. In this paper, we first used a technique of column flotation to remove UC from MSW fly ash. The influences of column flotation parameters on the recovery efficiency of UC were systematically studied. It was found that the UC recovery efficiency was greatly influenced by the gas flow rate, pH value, collector kerosene's concentration and the types of fly ash. By optimizing the above parameters, we have successfully removed 61.2% of the UC from MSW fly ash having 5.24% UC content. The removal mechanism was well accounted for the kinetic theory of column flotation and surface-chemistry theory. The results indicate that the column flotation technique is effective in removing the UC from MSW fly ash, and show that there is a strong possibility for practical application of this technique in removing the organic contaminants from MSW fly ash.

  20. Application of fly ash as an adsorbent for Estradiol in animal waste.

    PubMed

    Norris, Pauline; Hagan, Stephanie; Cohron, Martin; Zhao, Houying; Pan, Wei-Ping; Li, Kawang

    2015-09-15

    The contamination of agricultural ground with estrogen compounds through application of animal wastes is a present concern. At the same time, current uses for waste fly ash having high carbon content are limited. To help mitigate these problems, we examine using waste fly ash as a useful adsorbent for Estradiol in pig waste digests. In this study, Estradiol was added to vials containing water and fly ash from several different power plants. After an extraction process, the amount of Estradiol in the water was measured. Commercial activated carbon was also used for comparison purposes. Vials containing varying concentrations of Estradiol and no trapping material were used as a control. The results from this study indicate that fly ash can be used as a trapping material for Estradiol in water, but that commercially available activated carbon can trap about an order of magnitude more Estradiol than the fly ash and that the effects of the fly ash matrix can both inhibit and promote the solvation of Estradiol into water depending possibly upon pH and cation concentration effects. In addition, preliminary extraction studies using pig waste digest indicate that fly ash can be used as adsorbent for Estradiol present in pig waste. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. [Fly ash-catalyzed oxidation of p-nitro phenol with H2O2].

    PubMed

    Zhang, Ai-Li; Deng, Fang-Fang; Zhou, Ji-Ti; Jin, Ruo-Fei; Liang, Li-Li; Zhang, Guo-Liang

    2009-07-15

    Fly ash was investigated as a catalyst in the oxidation of p-nitro phenol (PNP) with H2O2 at ambient temperature and pressure. The physical and chemical properties of fly ash were analyzed. The effects of fly ash composition, pretreatment methods and other parameters (such as dosage, pH, reaction time and oxidant concentration) on PNP removal rate were studied. It was found that fly ash with larger specific surface area and higher carbon content demonstrated higher catalytic activity. Heat treatment (350 degrees C) on fly ash could effectively improve the PNP removal rate. With an initial H2O2 concentration of 200 mg/L, 60 g/L heat-treated fly ash could remove 62.38% PNP at 25 degrees C, pH = 2. Specific surface area, carbon and metal oxide contents of fly ash play an important role in the catalysis process. The adsorption control experiment showed that adsorption was the main effect (65.97%) in the catalysis process. The activity of the catalyst gradually increased during its reuse. The PNP removal rate could reach 82.47% and 98.72% in the second and third rounds of reuse, respectively. The removal rate remained at about 99% in the rest 9 rounds of reuse. And the catalytic properties decreased after 12 times uses.

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

    SciTech Connect

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

    2008-05-15

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

  3. Sintering of MSW fly ash for reuse as a concrete aggregate.

    PubMed

    Mangialardi, T

    2001-10-12

    The sintering process of municipal solid waste (MSW) fly ash was investigated in order to manufacture sintered products for reuse as concrete aggregates. Four types of fly ash resulting from different Italian MSW incineration plants were tested in this study. A modification of the chemical composition of MSW fly ash--through a preliminary four-stage washing treatment of this material with water--was attempted to improve the chemical and mechanical characteristics of sintered products.The sintering treatment of untreated or washed fly ash was performed on cylindrical compact specimens (15 mm in diameter and 20mm in height) at different compact pressures, sintering temperatures and times.The sintering process of untreated MSW fly ashes proved to be ineffective for manufacturing sintered products for reuse as a construction material, because of the adverse chemical characteristics of these fly ashes in terms of sulfate, chloride, and vitrifying oxide contents.A preliminary washing treatment of MSW fly ash with water greatly improved the chemical and mechanical characteristics of sintered products and, for all the types of fly ash tested, the sintered products satisfied the Italian requirements for normal weight aggregates for use in concretes having a specified strength not greater than 12 and 15N/mm(2), when measured on cylindrical and cubic specimens, respectively.A compact pressure of 28 N/mm(2), a sintering temperature of 1140 degrees C, and a sintering time of 60 min were the best operating conditions for manufacturing sintered products of washed MSW fly ash.

  4. Leachate concentrations from water leach and column leach tests on fly ash-stabilized soils

    SciTech Connect

    Bin-Shafique, S.; Benson, C.H.; Edil, T.B.; Hwang, K.

    2006-01-15

    Batch water leaching tests (WLTs) and column leaching tests (CLTs) were conducted on coal-combustion fly ashes, soil, and soil-fly ash mixtures to characterize leaching of Cd, Cr, Se, and Ag. The concentrations of these metals were also measured in the field at two sites where soft fine-grained soils were mechanically stabilized with fly ash. Concentrations in leachate from the WLTs on soil-fly ash mixtures are different from those on fly ash alone and cannot be accurately estimated based on linear dilution calculations using concentrations from WLTs on fly ash alone. The concentration varies nonlinearly with fly ash content due to the variation in pH with fly ash content. Leachate concentrations are low when the pH of the leachate or the cation exchange capacity (CEC) of the soil is high. Initial concentrations from CLTs are higher than concentrations from WLTs due to differences in solid-liquid ratio, pH, and solid-liquid contact. However, both exhibit similar trends with fly ash content, leachate pH, and soil properties. Scaling factors can be applied to WLT concentrations (50 for Ag and Cd, 10 for Cr and Se) to estimate initial concentrations for CLTs. Concentrations in leachate collected from the field sites were generally similar or slightly lower than concentrations measured in CLTs on the same materials. Thus, CLTs appear to provide a good indication of conditions that occur in the field provided that the test conditions mimic the field conditions. In addition, initial concentrations in the field can be conservatively estimated from WLT concentrations using the aforementioned scaling factors provided that the pH of the infiltrating water is near neutral.

  5. Solid by-products of coal combustion: Fly ash as a source of industrial minerals

    SciTech Connect

    Bhagwat, S.B.; Rapp, D.M.; Bukowski, J.M.

    1996-12-31

    Fly ash is one of the most important by-products of coal combustion. It is a complex mix of cenospheres, reactive glasses, magnetite and carbon, in addition to minor quantities of other minerals. Fly ash components are determined by the type of coal, the combustion technology, material collection system and the temperature of combustion. The changing mix of coal burned in power plants is increasingly making the fly ash characteristics independent of the locally mined coal. Fly ash is thus becoming a raw material independent of the existence of a local coal mining industry. Currently, about 65 million tons of fly ash are generated annually in the United States. This is equivalent to the crushed stone production of such highly industrialized states as Illinois. Only about twenty percent of the total fly ash are currently used, mostly in low value applications such as road building materials and concrete additions. The fly ash currently represents an environmental and financial liability to electric utilities. The increasingly competitive and boundaryless electricity market in the US increases the incentive to look at fly ash in terms of its individual components and recognize their potential as industrial minerals in the production of value added materials. For example, zeolites and other adsorbents could be produced from reactive glasses, magnetite could be used in pigments and ferrite manufacture, activated carbon could serve in pollution control and cenospheres could be used to make lightweight ceramics. If one begins to look at fly ash as a source of industrial minerals and not as a waste product, this change in perspective could turn a financial and environmental liability into an economic opportunity.

  6. Chlorobenzenes removal from municipal solid waste incineration fly ash by surfactant-assisted column flotation.

    PubMed

    Huang, Ying; Takaoka, Masaki; Takeda, Nobuo

    2003-07-01

    The organic contaminants in municipal solid waste incineration (MSWI) fly ash, including chlorinated aromatic compounds and polycyclic aromatic hydrocarbons, have high toxicity and a potential negative impact on the environment. An effective and low energy consumption technique to remove the organic contaminants from MSWI fly ash is required urgently. Organic contaminants, such as chlorobenzenes (CBzs), in MSWI fly ash are known to become enriched in the unburnt carbon (UC) fraction. It is proposed that removal of UC from fly ash will result in the effective removal of most organic micropollutants. In this research, we use a technique of surfactant-assisted column flotation to decontaminate MSWI fly ash by removal of the CBzs-enriched UC from MSWI fly ash. We find that 39.8% of CBzs can be removed from fresh MSWI fly ash with 61.7% UC removal efficiency, whereas only 33.2% of CBzs can be removed from weathered MSWI fly ash with a low UC removal efficiency of 33.7%. By adding a mixture of two kinds of surfactants: sorbitan mono-oleate and polyoxyethylene (20) sorbitan mono-oleate to the weathered fly ash, 47.0% of CBzs were removed at the hydrophile lipophile balance value of 13.5, while the UC removal efficiency increased to 49.0%. The results show that surfactants can enhance CBzs and UC removal efficiencies during the column flotation process. Higher CBzs and UC removal efficiencies can be expected by further optimizing the conditions of surfactant-assisted column flotation.

  7. Construction of an embankment with a fly and bottom ash mixture: field performance study

    SciTech Connect

    Yoon, S.; Balunaini, U.; Yildirim, I.Z.; Prezzi, M.; Siddiki, N.Z.

    2009-06-15

    Fly ash and bottom ash are coal combustion by-products (CCBPs) that are generated in large quantities throughout the world. It is often economical to dispose ash as mixtures rather than separately; that notwithstanding, only a few studies have been performed to investigate the behavior of fly and bottom ash mixtures, particularly those with high contents of fly ash. Also, there is very limited data available in the literature on the field performance of structures constructed using ash mixtures. This paper describes the construction and the instrumentation of a demonstration embankment built with an ash mixture (60:40 by weight of fly ash:bottom ash) on State Road 641, Terre Haute, Ind. Monitoring of the demonstration embankment was conducted for a period of 1 year from the start of construction of the embankment. The settlement of the embankment stabilized approximately 5 months after the end of its construction. According to horizontal inclinometer readings, the differential settlement at the top of the embankment is about 5 mm. Results from field quality control tests performed during construction of the demonstration embankment and monitoring data from vertical and horizontal inclinometers and settlement plates indicate that the ash mixture investigated can be considered an acceptable embankment construction material.

  8. Mercury adsorption characteristics of HBr-modified fly ash in an entrained-flow reactor.

    PubMed

    Zhang, Yongsheng; Zhao, Lilin; Guo, Ruitao; Song, Na; Wang, Jiawei; Cao, Yan; Orndorff, William; Pan, Wei-ping

    2015-07-01

    In this study, the mercury adsorption characteristics of HBr-modified fly ash in an entrained-flow reactor were investigated through thermal decomposition methods. The results show that the mercury adsorption performance of the HBr-modified fly ash was enhanced significantly. The mercury species adsorbed by unmodified fly ash were HgCl2, HgS and HgO. The mercury adsorbed by HBr-modified fly ash, in the entrained-flow reactor, existed in two forms, HgBr2 and HgO, and the HBr was the dominant factor promoting oxidation of elemental mercury in the entrained-flow reactor. In the current study, the concentration of HgBr2 and HgO in ash from the fine ash vessel was 4.6 times greater than for ash from the coarse ash vessel. The fine ash had better mercury adsorption performance than coarse ash, which is most likely due to the higher specific surface area and longer residence time. Copyright © 2015. Published by Elsevier B.V.

  9. Integrated acid mine drainage management using fly ash.

    PubMed

    Vadapalli, Viswanath R K; Gitari, Mugera W; Petrik, Leslie F; Etchebers, Olivier; Ellendt, Annabelle

    2012-01-01

    Fly Ash (FA) from a power station in South Africa was investigated to neutralise and remove contaminants from Acid Mine Drainage (AMD). After this primary treatment the insoluble FA residue namely solid residue (SR) was investigated as a suitable mine backfill material by means of strength testing. Moreover, SR was used to synthesise zeolite-P using a two-step synthesis procedure. Furthermore, the zeolite-P was investigated to polish process water from the primary FA-AMD reaction. The main objective of this series of investigations is to achieve zero waste and to propose an integrated AMD management using FA. Fly Ash was mixed with AMD at various predetermined FA-AMD ratios until the mixtures achieved circumneutral pH or higher. The supernatants were then analyzed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Ion Chromatography (IC) for cations and anions respectively. The physical strength testing of SR was carried out by mixing it with 3% Ordinary Portland Cement (OPC) and curing for 410 days. Synthesis of zeolite-P using SR was carried out by two step synthesis procedure: ageing for 24 hours followed by a mild hydrothermal synthesis at 100°C for 4 days. The polishing of process water from primary AMD treatment using FA was ascertained by mixing the process water with zeolite at a liquid to solid ratio of 100:1 for 1 hour. The results indicated that FA can be successfully used to ameliorate AMD. High removal of major AMD contaminants Fe, Al, Mg, Mn and sulphate was achieved with the ash treatment and trace elements such as Zn, Ni, Cu and Pb were also removed by the FA. Strength testing over 410 days indicated that the material gained strength over the testing period. The maximum unconfined compressive strength and elastic modulus was observed to be approximately 0.3 MPa and 150 Mpa respectively. The X-ray diffraction (XRD) analysis of the synthesized product indicated that SR was successfully converted into zeolite-P with some mullite phase

  10. Salt-soda sinter process for recovering aluminum from fly ash

    DOEpatents

    McDowell, W.J.; Seeley, F.G.

    A method for recovering aluminum values from fly ash comprises sintering the fly ash with a mixture of NaCl and Na/sub 2/CO/sub 3/ to a temperature in the range 700/sup 0/ to 900/sup 0/C for a period of time sufficient to convert greater than 90% of the aluminum content of the fly ash into an acidsoluble fraction and then contacting the thus-treated fraction with an aqueous solution of nitric or sulfuric acid to effect dissolution of aluminum and other metal values in said solution.

  11. Salt-soda sinter process for recovering aluminum from fly ash

    DOEpatents

    McDowell, William J.; Seeley, Forest G.

    1981-01-01

    A method for recovering aluminum values from fly ash comprises sintering the fly ash with a mixture of NaCl and Na.sub.2 CO.sub.3 to a temperature in the range 700.degree.-900.degree. C. for a period of time sufficient to convert greater than 90% of the aluminum content of the fly ash into an acid-soluble fraction and then contacting the thus-treated fraction with an aqueous solution of nitric or sulfuric acid to effect dissolution of aluminum and other metal values in said solution.

  12. The influence of fly ash and shell-fish on physical property of concrete cement

    NASA Astrophysics Data System (ADS)

    Rauf, Nurlaela; Hasruddin, M.

    2012-06-01

    The waste fly ash and shell fish are added to base material of cement (clinker, gypsum, trash and lime stone), for environmental reason. The ratio fly ash and shell fish was varied respectively 375:125; 250:250; 125:375, in grams weight for 2500 grams of total material. The chemical composition of raw material was determined by using x-rays fluorescence (XRF). Physical properties of sample match with Standar Nasional Indonesia (SNI). The physical properties of the best sample is made from composition of fly ash and shell fish as a substitution material on cement was 10% in weight, with ratio 250:250 in grams weight.

  13. Recovery of metals from power plant fly ash by carbochlorination with phosgene

    SciTech Connect

    Adelman, D.J.; Burnet, G.

    1983-01-01

    The HiChlor process for recovery of metals from power plant fly ash and other coal-conversion solid wastes is described. Results are presented for the production of volatile metal chlorides from fly ash by carbochlorination with phosgene. Data are included for reaction rates measured gravimetrically for temperatures of 450 to 800/sup 0/C and phosgene partial pressures of 10 to 100 kPa, and for chemisorption and B.E.T. isotherms used to determine active and total surface areas as a function of fly-ash conversion. Implications in terms of HiChlor reactor design are discussed.

  14. Salt-soda sinter process for recovering aluminum from fly ash

    SciTech Connect

    Mcdowell, W.J.; Seeley, F.G.

    1981-03-03

    A method for recovering aluminum values from fly ash comprises sintering the fly ash with a mixture of NaCl and Na2CO3 to a temperature in the range 700*-900* C for a period of time sufficient to convert greater than 90% of the aluminum content of the fly ash into an acid-soluble fraction and then contacting the thus-treated fraction with an aqueous solution of nitric or sulfuric acid to effect dissolution of aluminum and other metal values in said solution.

  15. The effect of fly ash on the mechanical properties of cinder lightweight aggregate concrete

    NASA Astrophysics Data System (ADS)

    Xiao, Liguang; Jiang, Dawei

    2017-04-01

    The volcanic cinder is a kind of porous rock with good performance and is formed by the cooling of the volcanic eruption. This paper studies the effect of fly ash on the mechanical properties of cinder lightweight aggregate concrete. Results show the mechanical properties of cinder lightweight aggregate concrete is significantly improved with fly ash, and it has a maximum strength value when the dosage is 35%; the early strength of lightweight aggregate concrete is greatly improved, when we extend the grinding time of fly ash, decrease the particle size and increase the activity.

  16. Aggregate material formulated with MSWI bottom ash and APC fly ash for use as secondary building material

    SciTech Connect

    Valle-Zermeño, R. del; Formosa, J.; Chimenos, J.M.; Martínez, M.; Fernández, A.I.

    2013-03-15

    Highlights: ► A concrete formulation was optimized using Bottom Ash and APC ash. ► 10% of APC ash achieves good compromise between economic and performance aspects. ► The crushed concrete was evaluated as secondary building granular material. ► The environmental behavior allows its use as secondary material. ► The abrasion resistance is not good enough for its use as a road sub-base material. - Abstract: The main goal of this paper is to obtain a granular material formulated with Municipal Solid Waste Incineration (MSWI) bottom ash (BA) and air pollution control (APC) fly ash to be used as secondary building material. Previously, an optimum concrete mixture using both MSWI residues as aggregates was formulated. A compromise between the environmental behavior whilst maximizing the reuse of APC fly ash was considered and assessed. Unconfined compressive strength and abrasion resistance values were measured in order to evaluate the mechanical properties. From these results, the granular mixture was not suited for certain applications owing to the high BA/APC fly ash content and low cement percentages used to reduce the costs of the final product. Nevertheless, the leaching test performed showed that the concentrations of all heavy metals were below the limits established by the current Catalan legislation for their reutilization. Therefore, the material studied might be mainly used in embankments, where high mechanical properties are not needed and environmental safety is assured.

  17. Power-plant fly-ash utilization: a chemical processing perspective

    SciTech Connect

    Burnet, G.; Murtha, M.J.

    1981-01-01

    The 1976 Resource Conservation and Recovery Act (RCRA) deals with the management of solid and hazardous wastes, and encourages energy and resource recovery. Recent research has indicated that solid wastes from coal combustion, including fly ash, could be classified as hazardous under present EPA definitions. The seriousness of this possibility has been recognized and new rules for coal ash waste disposal are being considered. Ames Laboratory research on fly ash utilization as an alternative to disposal includes extraction of metals from the ash and discovery of uses for the process residues. Recovery of alumina and iron oxides by physical and chemical processing would permit large scale utilization of fly ash and help reduce dependency on imports. One of the processes investigated uses a lime-soda sinter method to form soluble aluminate compounds from mixtures of fly ash, limestone, and soda ash. The aluminates are extracted, treated to remove silicates, and precipitated: the precipitate is calcined to metallurgical grade alumina. The extract residue shows promise as a raw material for the production of Portland cement. Process economics are presented, and the effects of alumina and silica contents of the fly ash, sintering temperatures and time, and sales credits for by-products are discussed.

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

    SciTech Connect

    Edward K. Levy; Christopher Kiely

    2004-11-01

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

  19. Effect of leachate solutions from fly and bottom ash on groundwater quality

    NASA Astrophysics Data System (ADS)

    Kopsick, Deborah A.; Angino, Ernest E.

    1981-12-01

    Leaching experiments on fly and bottom ash for Ca, Mg, Na, K, Fe, Mn, Zn, Cu and Pb indicated a potential for contamination of ground- and surface-water supplies. Due to the variability in chemical composition of coals, it is difficult to make generalizations concerning the chemistry of leachate solutions from the ashes of the coals. A decrease in concentration with time of leaching was observed for all elements, except for Ca which was released at a constant rate. Fly ash from a Missouri coal generated a leachate enriched in Pb, Zn, Cu, Fe, Mn and Cd, reflective of the high Pb/1bZn mineralization present in the surrounding area. With a pH of 3.0 this ash has the greatest potential for groundwater contamination. Conversely, leachates from Wyoming fly and bottom ashes exhibited low trace-metal concentrations. These same solutions were high in K, Na, Ca and Mg, and also showed strong pozzolanic behvior, which will reduce the leachability of these ashes. In most instances, fly and bottom ash from Kentucky and Illinois coals yielded leachates intermediate in elemental composition to leachates of Missouri and Wyoming coal ashes. Leaching experiments indicate that it is not valid to predict the chemistry of leachates from fly and bottom ash based solely on the chemical composition of the ash. From the limited number of parameters and sites examined in this study, it is clear that many of the problems related to leachates from fly and bottom ash and gob piles are site specific as well as specific to the source of coal burned. These results are, nevertheless, indicative of problems likely to be encountered in working with these materials.

  20. Desulfurization Characteristics of Fly Ash Recirculation and Combustion in the Circulating Fluidized Bed Boiler

    NASA Astrophysics Data System (ADS)

    Li, S. F.; Fang, M. X.; Yu, B.; Wang, Q. H.; Luo, Z. Y.

    The experiments of the fly ash recycle combustion using Guizhou anthracite were carried out in a bench scale circulating fluidized bed (CFB) combustor. Effects of some key operating parameters such as recycle ash to coal mass ratio (Ca to S molar ratio), temperature, reactivation modeof fly ash, circulation rateand fluidization velocity on the desulfurization efficiency were intensively investigated. It is shown that thelimestone utilization efficiency could be improved about 30% with the following operating conditions: the mass ratio of fly ash (reactivated by water and dried at 90°C) to coal was 0.45, the furnace temperature was 880°C, the water to ash mass ratio was 4.5% (the water-to-calcium molar ratio was 0.55) and circulation rate was 18.

  1. Comprehensive phase characterization of crystalline and amorphous phases of a Class F fly ash

    SciTech Connect

    Chancey, Ryan T.; Stutzman, Paul; Juenger, Maria C.G.; Fowler, David W.

    2010-01-15

    A comprehensive approach to qualitative and quantitative characterization of crystalline and amorphous constituent phases of a largely heterogeneous Class F fly ash is presented. Traditionally, fly ash composition is expressed as bulk elemental oxide content, generally determined by X-ray fluorescence spectroscopy. However, such analysis does not discern between relatively inert crystalline phases and highly reactive amorphous phases of similar elemental composition. X-ray diffraction was used to identify the crystalline phases present in the fly ash, and the Rietveld quantitative phase analysis method was applied to determine the relative proportion of each of these phases. A synergistic method of X-ray powder diffraction, scanning electron microscopy, energy dispersive spectroscopy, and multispectral image analysis was developed to identify and quantify the amorphous phases present in the fly ash.

  2. BIOLOGICAL EFFECTS OF OIL FLY ASH AND RELEVANCE TO AMBIENT AIR PARTICULATE MATTER

    EPA Science Inventory

    Epidemiologic studies have demonstrated increased human morbidity and mortality with elevations in the concentration of ambient air particulate matter (PM). Fugitive fly ash from the combustion of oil and residual fuel oil significantly contributes to the ambient air particle bur...

  3. Coal Combustion Residual Beneficial Use Evaluation: Fly Ash Concrete and FGD Gypsum Wallboard

    EPA Pesticide Factsheets

    This page contains documents related to the evaluation of coal combustion residual beneficial use of fly ash concrete and FGD gypsum wallboard including the evaluation itself and the accompanying appendices

  4. [Study on vitrification of fly ashes from municipal wastes incinerator with a plasma torch].

    PubMed

    Pan, Xin-chao; Ma, Zeng-yi; Wang, Qin; Tu, Xin; Yan, Jian-hua

    2008-04-01

    TCLP analysis (USEPA method 1311) was employed on fly ash in order to analyze the metals leachability and the concentration of cadmium was 0.3225 mg/L which exceeded state TCLP standard(0.3 mg/L). According to USEPA method 1613, I-TEQ of PCDD/Fs in fly ash was 0.45 ng/g. Then a double arcs DC plasma torch was developed to vitrified fly ash. And the results showed that heavy metals were mostly immobilized in the vitrified slag and also I-TEQ of PCDD/Fs in fly ash was destroyed near 91.6%. The morphology of vitrified slag was amorphous state which showed the glassy slag of SiO2 and the microstructure of slag was very compact.

  5. Fractionation of Heavy Metals in Fly Ash from Wood Biomass Using the BCR Sequential Extraction Procedure.

    PubMed

    Jukić, Mirela; Ćurković, Lidija; Šabarić, Jasenka; Kerolli-Mustafa, Mihone

    2017-08-20

    The aim of this study was to extract the wood biomass fly ash fractions by a three-stage sequential extraction method for acetic acid and ion exchangeable (BCR 1), hydroxylamine hydrochloride reduction (BCR 2), and hydrogen peroxide oxidation (BCR 3) fractions in order to access the leaching behavior of this residue. The fly ash was collected as a by-product from the processing of mixed wood biomass in Udbina combustion facility, Croatia. Concentrations of several elements (As, Cd, Cr, Cu, Ni, Pb and Zn) in all extracts were determined by inductively coupled plasma atomic emission spectrometry. The acidic exchangeable form of the metals was used to evaluate the potential ecological risk of biomass fly ash. According to calculated potential ecological risk index, it is confirmed that mobility of Ni and As has major environmental impact. However the results of potential ecological risk show that biomass fly ash had a low risk.

  6. Research on carbon content in fly ash from circulating fluidized bed boilers

    SciTech Connect

    Xianbin Xiao; Hairui Yang; Hai Zhang; Junfu Lu; Guangxi Yue

    2005-08-01

    The carbon content in the fly ash from most Chinese circulating fluidized bed (CFB) boilers is much higher than expected, which directly influences the combustion efficiency. In the present paper, carbon burnout was investigated in both field tests and laboratory experiments. The effect of coal property, operation condition, gas-solid mixing, char deactivation, residence time, and cyclone performance are analyzed seriatim based on a large amount of experimental results. A coal index is proposed to describe the coal rank, having a strong effect on the char burnout. Bad gas-solid mixing in the furnace is another important reason of the higher carbon content in the fly ash. Some chars in the fly ash are deactivated during combustion of large coal particles and have very low carbon reactivity. Several suggestions are made about design, operation, and modification to reduce the carbon content in the fly ash. 14 refs., 14 figs., 1 tab.

  7. Liquidus (Ca+Mg)-rich exsolution phases in low-sulfur fly ash

    SciTech Connect

    O'Connor, J.T.; Meeker, G.M.

    1999-07-01

    Ca- and Mg-rich fly ash samples from an electric power plant burning low-sulfur Powder River Coal were analyzed using optical petrographic microscope (OPM), scanning electron microscope (SEM), electron microprobe analyzer (EMPA), and Gandolfi and bulk-powder X-ray diffraction (XRD) techniques. Abundant Ca and Mg in the fly ash, probably originating from dispersed authigenic and residual minerals in the coal feed stock, flux the molten fly ash, effectively allowing many crystalline phases to achieve ordering, to separate from each other, and to grow to appreciable size (>10{micro}m) in the brief time (<20 sec) they spend at high temperature. Phases identified from the (Ca+Mg)-rich fly ash are listed in a table and shown in figures.

  8. The Effect of Fly Ash on the Corrosion Behaviour of Galvanised Steel Rebarsin Concrete

    NASA Astrophysics Data System (ADS)

    Tittarelli, Francesca; Mobili, Alessandra; Bellezze, Tiziano

    2017-08-01

    The effect of fly ash on the corrosion behaviour of galvanised steel rebars in cracked concrete specimens exposed to wet-dry cycles in a chloride solution has been investigated. The obtained results show that the use of fly ash, replacing either cement or aggregate, always improves the corrosion behaviour of galvanised steel reinforcements. In particular, the addition of fly ash, even in the presence of concrete cracks, decreases the corrosion rate monitored in very porous concretes, as those with w/c = 0.80, to values comparable with those obtained in good quality concretes, as those with w/c = 0.45. Therefore, fly ash cancels the negative effect, at least from the corrosion point of view, of a great porosity of the cement matrix.

  9. Synthesis of geopolymer composites from a mixture of ferronickel slag and fly ash

    NASA Astrophysics Data System (ADS)

    Liu, Yun; Zhang, Kang; Feng, Enjuan; Zhao, Hongyi; Liu, Futian

    2017-03-01

    The synthesis of geopolymers using ferronickel slag and fly ash under alkaline activation was studied. In order to study the effects of different fly ash content on the mechanical properties of the geopolymers produced, the compressive strength of samples was tested at 3, 7, 28 days. The results showed that when the fly ash content was 40%, the compressive strength reached the highest (110.32MPa) at 28 days. XRD analysis showed that the ferronickel slag geopolymers had amorphous aluminosilicate phase formation, indicating that the hydration reaction occurred. FTIR analysis showed the reaction of the geopolymers generated at Si-O-T (Si, Al) and Al-O-Si three-dimensional network. In SEM images, the structure of the geopolymers with 40% fly ash was more compact and cohesive.

  10. Kinetics of fly ash beneficiation by carbon burnout. Quarterly report, October 1996--December 1996

    SciTech Connect

    Dodoo, J.N.; Okoh, J.M.; Diaz, A.

    1997-06-01

    The presence of carbon in fly ash requires an increase in the dosage of the air-entraining admixture for concrete mix, and may cause the admixture to lose efficiency. Specifying authorities for the concrete producers have set maximum allowable levels of residual carbon. These levels are the so called {open_quotes}Loss On Ignition{close_quotes} (LOI). The concrete producer`s day-to-day purchasing decisions sets the LOI at 4%. The objective of the project is to investigate the kinetics of oxidation of residual carbon present in coal fly ash as a possible first step toward producing low-carbon fly ash from high-carbon, low quality fly ash.

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

    PubMed

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

    2009-07-01

    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.

  12. Potential of fly ash for neutralisation of acid mine drainage.

    PubMed

    Qureshi, Asif; Jia, Yu; Maurice, Christian; Öhlander, Björn

    2016-09-01

    Lignite (PK), bituminous (FI) and biomass (SE) fly ashes (FAs) were mineralogically and geochemically characterised, and their element leachability was studied with batch leaching tests. The potential for acid neutralisation (ANP) was quantified by their buffering capacity, reflecting their potential for neutralisation of acid mine drainage. Quartz was the common mineral in FAs detected by XRD with iron oxide, anhydrite, and magnesioferrite in PK, mullite and lime in FI, and calcite and anorthite in SE. All the FAs had high contents of major elements such as Fe, Si, Al and Ca. The Ca content in SE was six and eight times higher compared to PK and FI, respectively. Sulphur content in PK and SE was one magnitude higher than FI. Iron concentrations were higher in PK. The trace element concentrations varied between the FAs. SE had the highest ANP (corresponding to 275 kg CaCO3 tonne(-1)) which was 15 and 10 times higher than PK and FI, respectively. The concentrations of Ca(2+), SO4 (2-), Na(+) and Cl(-) in the leachates were much higher compared to other elements from all FA samples. Iron, Cu and Hg were not detected in any of the FA leachates because of their mild to strong alkaline nature with pH ranging from 9 to 13. Potassium leached in much higher quantity from SE than from the other ashes. Arsenic, Mn and Ni leached from PK only, while Co and Pb from SE only. The concentrations of Zn were higher in the leachates from SE. The FAs used in this study have strong potential for the neutralisation of AMD due to their alkaline nature. However, on the other hand, FAs must be further investigated, with scaled-up experiments before full-scale application, because they might leach pronounced concentrations of elements of concern with decreasing pH while neutralising AMD.

  13. The effect of fly ash and coconut fibre ash as cement replacement materials on cement paste strength

    NASA Astrophysics Data System (ADS)

    Bayuaji, R.; Kurniawan, R. W.; Yasin, A. K.; Fatoni, H. AT; Lutfi, F. M. A.

    2016-04-01

    Concrete is the backbone material in the construction field. The main concept of the concrete material is composed of a binder and filler. Cement, concrete main binder highlighted by environmentalists as one of the industry are not environmentally friendly because of the burning of cement raw materials in the kiln requires energy up to a temperature of 1450° C and the output air waste CO2. On the other hand, the compound content of cement that can be utilized in innovation is Calcium Hydroxide (CaOH), this compound will react with pozzolan material and produces additional strength and durability of concrete, Calcium Silicate Hydrates (CSH). The objective of this research is to explore coconut fibers ash and fly ash. This material was used as cement replacement materials on cement paste. Experimental method was used in this study. SNI-03-1974-1990 is standard used to clarify the compressive strength of cement paste at the age of 7 days. The result of this study that the optimum composition of coconut fiber ash and fly ash to substitute 30% of cement with 25% and 5% for coconut fibers ash and fly ash with similar strength if to be compared normal cement paste.

  14. Evaluation of chemical composition, physical properties and pozzolanic activity of fly ash in Florida. Final report, September 1992-December 1994

    SciTech Connect

    Zayed, A.M.; Terrelong, R.; Zafaranian, F.

    1995-02-01

    This investigation addresses the effect of variable loading in power stations on the material properties and quality of the produced Class F Fly Ash. In addition, two Class C fly ashes were examined for sulfate durability. The properties of the as-received Class F fly ash that were quantified include: oxides composition, oil content, carbon content, LOI, particle size distribution, fineness, mortar cube strength and reacted fly ash fraction. Class C fly ash was examined for its sulfate performance through assessing expansion measurements and cube strength. In addition, the mineralogical composition of the crystalline phases in the as-received ash and the hydrated mortar was examined using x-ray diffraction. The pozzolanic activity was found to be a function of the fly ash fineness and carbon content.

  15. Comparative adsorption of arsenic, boron, chromium, molybdenum and selenium on fresh and weathered fly ash.

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, S.; Donahoe, R. J.; Graham, E. Y.; Patel, D. V.

    2004-12-01

    Coal-fired electric power plants in the US generated over 130 million tons of fly ash and other combustion waste materials last year. While approximately 35% of the produced coal combustion by-products (CCBs) are recycled for beneficial use, the majority of the waste is impounded in lagoons and landfills located throughout the country. The EPA is currently re-evaluating these disposal facilities for regulation under Subtitle D. The objective of this study is to determine and compare the adsorption capacities of fresh and weathered fly ash for the toxic metals arsenic, boron, chromium, molybdenum, and selenium in order to evaluate the long-term mobility of these metals in the ash disposal environment. Two power plant sites were selected for study, one producing acidic ash and the other alkaline ash. Weathered ash samples were collected at each site from cores drilled from the surface through the bottom of ponds that have been closed for more than 35 years. Fresh fly ash was obtained directly from the power plants. Batch experiments were performed to study the competitive adsorption of As, B, Cr, Mo and Se on fresh and weathered ash materials. Experiments performed at pH values of 3, 4, 6, 8 and 10, using initial metal concentrations of 5 mg/L, show similar adsorption behavior for both ash compositions. The metal selectivity sequence for fresh fly ash is As >> Mo > Cr ~ Se ~ B. Maximum arsenic adsorption on fresh fly ash occurs at pH = 6 with almost 100% removal, while maximum arsenic adsorption on weathered ash takes place at pH = 3. Maximum adsorption of B, Cr, Mo and Se occurs at pH = 3 for both fresh and weathered ash. The experiments indicate that the adsorption capacity of fly ash for the metals of interest is reduced by weathering. Experiments are currently underway to compare the adsorption capacity of fresh and weathered fly ash for varying initial metal concentrations, ionic strength and solid/liquid ratio.

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

    PubMed

    Masala, Silvia; Bergvall, Christoffer; Westerholm, Roger

    2012-08-15

    Air pollution from coal combustion is of great concern in China because coal is the country's principal source of energy and it has been estimated that coal combustion is one of the main sources of polycyclic aromatic hydrocarbon (PAH) emissions in the nation. This study reports the concentrations of 15 PAHs including benzo[a]pyrene, dibenzo[a,l]pyrene, dibenzo[a,e]pyrene, dibenzo[a,i]pyrene and dibenzo[a,h]pyrene in a coal fly ash certified reference material (CRM) from China. To the best of our knowledge, dibenzo[a,l]pyrene, dibenzo[a,i]pyrene and dibenzo[a,h]pyrene concentrations in coal fly ash particles have not previously been reported. Benzo[a]pyrene is the only one of the studied hydrocarbons whose concentration in the coal fly ash CRM had previously been certified. The concentration of this species measured in this present work was twice the certified value. This is probably because of the exhaustive accelerated solvent extraction method employed. Consecutive extractions indicated an extraction recovery in excess of 95% for benzo[a]pyrene. For the other determined PAHs, repeat extractions indicated recoveries above 90%. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. Geochemical modeling and assessment of leaching from carbonated municipal solid waste incinerator (MSWI) fly ash.

    PubMed

    Wang, Lei; Chen, Qi; Jamro, Imtiaz Ali; Li, Rundong; Li, Yanlong; Li, Shaobai; Luan, Jingde

    2016-06-01

    Municipal solid waste incinerator (MSWI) fly ashes are characterized by high calcium oxide (CaO) content. Carbon dioxide (CO2) adsorption by MSWI fly ash was discussed based on thermogravimetry (TG)/differential thermal analysis (DTA), minerology analysis, and adapting the Stenoir equation. TG/DTA analysis showed that the weight gain of the fly ash below 440 °C was as high as 5.70 %. An adapted Stenoir equation for MSWI fly ash was discussed. The chloride in MSWI fly ash has a major impact on CO2 adsorption by MSWI fly ash or air pollution control (APC) residues. Geochemical modeling of the critical trace elements copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), and antimony (Sb) before and after carbonation was performed using a thermodynamic equilibrium model for solubility and a surface complexation model for metal sorption. Leaching of critical trace elements was generally found to be strongly dependent on the degree of carbonation attained, and their solubility appeared to be controlled by several minerals. Adsorption on ferrum (Fe) and aluminum (Al) colloids was also responsible for removal of the trace elements Cd, Pb, and Sb. We used Hakanson's potential ecological risk index (HPERI) to evaluate the risk of trace element leaching in general. The results demonstrate that the ecological risk showed a V-shaped dependency on pH; the optimum pH of the carbonated fly ash was found to be 10.3-11, resulting from the optimum carbonation (liquid-to-solid (L/S) ratio = 0.25, carbonation duration = ∼30-48 h). The dataset and modeling results presented here provide a contribution to assessing the leaching behavior of MSWI fly ash under a wide range of conditions.

  18. Performance characteristics of heavy media cyclones using fly ash-derived heavy media

    SciTech Connect

    Birlingmair, D.; Murtha, M.J.

    1982-03-01

    The potential for use of the magnetically separated iron-rich fraction of coal fly ash as heavy medium material for float-sink benefication of coal was investigated. Comparative coal beneficiation separations are made using commercial magnetite samples and magnetically separated fly ash samples. Laboratory experimentation is used to characterize the heavy media materials, determine particle durability, measure abrasion and corrosion of construction materials, compare media stabilities and viscosities, and determine flow circuit power requirements.

  19. Chemical species in fly ash from coal-burning power plants

    SciTech Connect

    Hulett, L.D. Jr.; Weinberger, A.J.; Northcutt, K.J.; Ferguson, M.

    1980-12-19

    Fly ash specimens from four power plants in the Tennessee Valley Authority system have been separated into three matrices: glass, mullite-quartz, and magnetic spinel. Chemical species of trace elements are defined to a large extent by the matrices that contain them. The magnetic component of fly ash is ferrite. The mullit-quartz phase is relatively pure and can be recovered as a resource.

  20. Fly ash design manual for road and site applications. Volume 2: Slurried placement

    SciTech Connect

    McLaren, R.J.; Balsamo, N.J.

    1986-10-01

    This report was produced as part of EPRI Research Project 2422. The goal of this project is to significantly increase the use of fly ash in all high volume uses and to increase its use in medium and high technology applications as well. This report is a utilization manual describing the design of various types of projects where fly ash has been used as a substitute for other common materials in high volume uses. High volume uses of fly ash are typified by structural and non-structural fills for site development, embankments for highways and railroads, backfills, highway subgrade improvement projects and base courses, grouting of subsurface voids, and other similar applications. This report is an integral part of the overall project and has been developed as a design manual pertaining to the use of fly ash as a construction material in these high volume uses. The manual is divided into two volumes. Volume 1 describes the use of fly ash conditioned with small amounts of water to produce a solid, soil-like material. This volume describes the use of fly ash mixed with sufficient water to create a fluid or semi-fluid material. In many applications, Portland cement and aggregate filler are also added to the mixture. The flowable nature of these materials determines the manner in which they are handled, placed, and used in construction. The following uses are discussed: Slurry Backfills, Grouting, and Hydraulic Fills. Miscellaneous uses are also discussed, including the use of fly ash in high fly ash concrete, unsintered synthetic aggregate, and slurry walls. Also included are three appendices containing additional information of interest to the designer: Mix Design, Laboratory Testing, and Bibliography. 19 refs., 53 figs., 12 tabs.

  1. Evaluating the Effects of the Kingston Fly Ash Release on Fish Reproduction: Spring 2009 - 2010 Studies

    SciTech Connect

    Greeley Jr, Mark Stephen; Adams, Marshall; McCracken, Kitty

    2012-05-01

    On December 22, 2008, a dike containing fly ash and bottom ash at the Tennessee Valley Authority's (TVA) Kingston Fossil Plant in East Tennessee failed and released a large quantity of ash into the adjacent Emory River. Ash deposits from the spill extended 4 miles upstream of the facility to Emory River mile 6 and downstream to Tennessee River mile 564 ({approx}8.5 miles downstream of the confluence of the Emory River with the Clinch River, and {approx}4 miles downstream of the confluence of the Clinch River with the Tennessee River). A byproduct of coal combustion, fly ash contains a variety of metals and other elements which, at sufficient concentrations and in specific forms, can be harmful to biological systems. The ecological effects of fly ash contamination on exposed fish populations depend on the magnitude and duration of exposure, with the most significant risk considered to come from elevated levels of certain metals in the ash, particularly selenium, on fish reproduction and fish early life stages (Lemly 1993; Besser and others 1996). The ovaries of adult female fish in a lake contaminated by coal ash were reported to have an increased frequency of atretic oocytes (dead or damaged immature eggs) and reductions in the overall numbers of developing oocytes (Sorensen 1988) associated with elevated body burdens of selenium. Larval fish exposed to selenium through maternal transfer of contaminants to developing eggs in either contaminated bodies of water (Lemly 1999) or in experimental laboratory exposures (Woock and others 1987, Jezierska and others 2009) have significantly increased incidences of developmental abnormalities. Contact of fertilized eggs and developing embryos to ash in water and sediments may also pose an additional risk to the early life stages of exposed fish populations through direct uptake of metals and other ash constituents (Jezierska and others 2009). The establishment and maintenance of fish populations is intimately associated with

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

    SciTech Connect

    Edward K. Levy; Christopher Kiely

    2005-11-01

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

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

    SciTech Connect

    Edward K. Levy; Christopher Kiely; Zheng Yao

    2006-08-31

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

  4. The gamma-ray and neutron shielding factors of fly-ash brick materials.

    PubMed

    Singh, Vishwanath P; Badiger, N M

    2014-03-01

    A comprehensive study of gamma-ray exposure build-up factors (EBFs) of fly-ash brick materials has been carried out for photon energies of 0.015-15 MeV up to a penetration depth of 40 mfp (mean free path) by a geometrical progression (GP) fitting method. The EBF values of the fly-ash brick materials were found to be dependent upon the photon energy, penetration depth and chemical composition, and were found to be higher than the values for mud bricks and common bricks. Above a photon energy of 3 MeV for large penetration depths (>10 mfp), the EBF becomes directly proportional to Zeq. EBFs of fly-ashes were found to be less than or equal to those of concrete for low penetration depths (<10 mfp) for intermediate photon energies up to 1.5 MeV. The EBF values of fly-ash materials were found to be almost independent of Si concentration. The fast neutron removal cross sections of the fly-ash brick materials, mud bricks and common bricks were also calculated to understand their shielding effectiveness. The shielding effectiveness of the fly-ash materials against gamma-ray radiation was lower than that of common and mud bricks.

  5. Industrial properties of lignitic and lignocellulosic fly ashes from Turkish sources

    SciTech Connect

    Demirbas, A.; Cetin, S.

    2006-01-21

    Fly ash is an inorganic matter from combustion of the carbonaceous solid fuels. More than half the electricity in Turkey is produced from lignite-fired power plants. This energy production has resulted in the formation of more than 13 million tons of fly ash waste annually. The presence of carbon in fly ash inducing common faults include adding unwanted black color and adsorbing process or product materials such as water and chemicals. One of the reasons for not using fly ash directly is its carbon content. For some uses carbon must be lower than 3%. Fly ash has been used for partial replacement of cement, aggregate, or both for nearly 70 years, and it is still used on a very limited scale in Turkey. The heavy metal content of industrial wastewaters is an important source of environmental pollution. Each of the three major oxides (SiO{sub 2} + Al{sub 2}O{sub 3} + Fe{sub 2}O{sub 3}) in fly ash can be ideal as a metal adsorbent.

  6. Utilization of MSWI fly ash for stabilization/solidification of industrial waste sludge.

    PubMed

    Qian, Guangren; Cao, Yali; Chui, Pengcheong; Tay, Joohwa

    2006-02-28

    This work investigated the potential for utilization of MSWI incineration fly ash as solidification binder to treat heavy metals-bearing industrial waste sludge. In the study, Municipal Solid Waste Incineration (MSWI) fly ash was used along with ordinary Portland cement to immobilize three different types of industrial sludge while MSWI incineration fly ash was stabilized at the same time. The results showed that the matrixes with heavy metals-bearing sludge and MSWI fly ash have a strong fixing capacity for heavy metals: Zn, Pb, Cu, Ni and Mn. Specimens with only 5-15% cement content was observed to be sufficient to achieve the target compressive strength of 0.3 MPa required for landfill disposal. An optimum mix comprising 45% fly ash, 5% cement and 50% of the industrial sludge could provide the required solidification and stabilization. Addition of MSWI can improve the strength of matrix. Meanwhile, the main hydration products of new S/S matrix are ettringite AFt, Friedel's salt and C-S-H. These hydration products play an important role in the fixing of heavy metals. The co-disposal of MSWI fly ash with heavy metals-bearing sludge can minimize the enlargement of the landfill volume and stabilize the heavy metals effectively.

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

    PubMed

    Ramanathan, Thulasya; Ting, Yen-Peng

    2016-10-01

    The increasing demand for energy and the generation of solid waste have caused an alarming rise in fly ash production globally. Since heavy metals continue to be in demand for the production of materials, resource recovery from the recycling of these wastes has the potential to delay the depletion of natural ores. The use of microorganisms for the leaching of metals, in a process called bioleaching, is an eco-friendly and economical way to treat the metal-laden wastes. Bioleaching of fly ash is challenging due largely to the alkaline nature and toxic levels of heavy metals which are detrimental to microbial growth and bioleaching activity. The present work reports the isolation of indigenous bacteria from a local fly ash landfill site and their bioleaching performance. 38 autochthonous strains of bacteria were isolated from eight samples collected and plated on five different media. 18 of the isolates showed bioleaching potential, with significant alkaline pH or fly ash tolerance. Genetic characterization of the strains revealed a dominance of Firmicutes, with Alkalibacterium sp. TRTYP6 showing highest fly ash tolerance of up to 20% w/v fly ash, and growth over a pH range 8-12.5. The organism selectively recovered about 52% Cu from the waste. To the best of our knowledge, this is the first time a study on bioleaching with extreme alkaliphiles is reported. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Destruction of inorganic municipal solid waste incinerator fly ash in a DC arc plasma furnace.

    PubMed

    Zhao, Peng; Ni, Guohua; Jiang, Yiman; Chen, Longwei; Chen, Mingzhou; Meng, Yuedong

    2010-09-15

    Due to the toxicity of dioxins, furans and heavy metals, there is a growing environmental concern on municipal solid waste incinerator (MSWI) fly ash in China. The purpose of this study is directed towards the volume-reduction of fly ash without any additive by thermal plasma and recycling of vitrified slag. This process uses extremely high-temperature in an oxygen-starved environment to completely decompose complex waste into very simple molecules. For developing the proper plasma processes to treat MSWI fly ash, a new crucible-type plasma furnace was built. The melting process metamorphosed fly ash to granulated slag that was less than 1/3 of the volume of the fly ash, and about 64% of the weight of the fly ash. The safety of the vitrified slag was tested. The properties of the slag were affected by the differences in the cooling methods. Water-cooled and composite-cooled slag showed more excellent resistance against the leaching of heavy metals and can be utilized as building material without toxicity problems. Copyright 2010 Elsevier B.V. All rights reserved.

  9. Geopolymeric adsorbents from fly ash for dye removal from aqueous solution.

    PubMed

    Li, Lin; Wang, Shaobin; Zhu, Zhonghua

    2006-08-01

    Adsorbents from coal fly ash treated by a solid-state fusion method using NaOH were prepared. It was found that amorphous aluminosilicate geopolymers would be formed. These fly ash-derived inorganic polymers were assessed as potential adsorbents for removal of some basic dyes, methylene blue and crystal violet, from aqueous solution. It was found that the adsorption capacity of the synthesised adsorbents depends on the preparation conditions such as NaOH:fly-ash ratio and fusion temperature with the optimal conditions being at 1.2:1 weight ratio of Na:fly-ash at 250-350 degrees C. The synthesised materials exhibit much higher adsorption capacity than fly ash itself and natural zeolite. The adsorption isotherm can be fitted by Langmuir and Freundlich models while the two-site Langmuir model producing the best results. It was also found that the fly ash derived geopolymeric adsorbents show higher adsorption capacity for crystal violet than methylene blue and the adsorption temperature influences the adsorption capacity. Kinetic studies show that the adsorption process follows the pseudo second-order kinetics.

  10. Properties of High Volume Fraction Fly Ash/Al Alloy Composites Produced by Infiltration Process

    NASA Astrophysics Data System (ADS)

    Kountouras, D. T.; Stergioudi, F.; Tsouknidas, A.; Vogiatzis, C. A.; Skolianos, S. M.

    2015-09-01

    In the present study, pressure infiltration is employed to synthesize aluminum alloy 7075-fly ash composites. The microstructure and chemical composition of the fly ash and the produced composite material was examined using optical and scanning electron microscopy, as well as x-ray diffraction. Several properties of the produced composite material were examined and evaluated including macro-hardness, wear, thermal expansion, and corrosion behavior. The wear characteristics of the composite, in the as-cast conditions, were studied by dry sliding wear tests. The corrosion behavior of composite material was evaluated by means of potentiodynamic corrosion experiments in a 3.5 wt.% NaCl solution. The composite specimens exhibit a homogeneous distribution of fly ash particles and present enhanced hardness values, compared to the matrix material. The high volume fraction of the fly ash reinforcement (>40%) in the composite material led to increased wear rates, attributed to the fragmentation of the fly ash particles. However, the presence of fly ash particles in the Al alloy matrix considerably decreased the coefficiency of thermal expansion, while resulting in an altered corrosion mechanism of the composite material with respect to the matrix alloy.

  11. Coal fly ash disposal in the ocean: an alternative worth considering

    SciTech Connect

    Crecelius, E.A.

    1981-10-01

    Chemical and biological experiments measured the solubility of 16 elements in coal fly ash and the short-term toxicity of coal fly ash to clams and phytoplankton. Of the elements studied, 10 to 60% of the As, Br, Cr, Sb, Se, Ni, Pb, and Sr dissolved within a 24-hour period. Elements which were less than 10% soluble in 24-hours included Cu, Zn, Na, La, Sc, Fe, Co and Eu. Littleneck clams (Protothaca staminea) were exposed to coal fly ash in flowing seawater for a 25-day period. At the end of the exposure Cu concentration in gills was 15 ..mu..g g/sup -1/ dry wt compared to 6 ..mu..g g/sup -1/ in control clams. Elements that were not elevated in the exposed clams were Mn, Fe, Ni, Zn, Se and As. The effects of the soluble fraction of coal fly ash on primary production was measured by /sup 14/C uptake rate on coastal phytoplankton. The addition of soluble coal fly ash material had no effect on the /sup 14/C uptake rate of phytoplankton. These measurements were made in the productive Washington shelf water during August. The literature indicates coal fly ash has a relatively low toxicity to plants and animals. Disposal methods could be designed so EPA water quality criteria levels would not be exceeded except in the immediate vicinity of the dumpsite.

  12. Removal of trivalent chromium from aqueous solution by zeolite synthesized from coal fly ash.

    PubMed

    Wu, Deyi; Sui, Yanming; He, Shengbing; Wang, Xinze; Li, Chunjie; Kong, Hainan

    2008-07-15

    The capability of 14 zeolites synthesized from different fly ashes (ZFAs) to sequestrate Cr(III) from aqueous solutions was investigated in a batch mode. The influence of pH on the sorption of Cr(III) was examined. ZFAs had a much greater ability than fly ash to remove Cr(III), due to the high cation exchange capacity (CEC) and the high acid neutralizing capacity (ANC) of ZFAs. The mechanism of Cr(III) removal by ZFAs involved ion exchange and precipitation. A high-calcium content in both the fly ashes and ZFAs resulted in a high ANC value and, as a result, a high immobilization capacity for Cr(III). The pH strongly influenced Cr(III) removal by ZFAs. Inside the solubility range, removal of chromium increased with increasing pH. Hydroxysodalite made from a high-calcium fly ash had a higher sorptive capacity for Cr(III) than the NaP1 zeolite from medium- and low-calcium fly ashes. On the other hand, at pH values above the solubility range, the efficiency of chromium removal by the ZFAs approached 100% due to the precipitation of Cr(OH)3 on the sorbent surfaces. It is concluded that ZFAs and high-calcium fly ashes may be promising materials for the purification of Cr(III) from water/wastewater.

  13. Effect of temperature on the hydration of Portland cement blended with siliceous fly ash

    SciTech Connect

    Deschner, Florian; Lothenbach, Barbara; Winnefeld, Frank; Neubauer, Jürgen

    2013-10-15

    The effect of temperature on the hydration of Portland cement pastes blended with 50 wt.% of siliceous fly ash is investigated within a temperature range of 7 to 80 °C. The elevation of temperature accelerates both the hydration of OPC and fly ash. Due to the enhanced pozzolanic reaction of the fly ash, the change of the composition of the C–S–H and the pore solution towards lower Ca and higher Al and Si concentrations is shifted towards earlier hydration times. Above 50 °C, the reaction of fly ash also contributes to the formation of siliceous hydrogarnet. At 80 °C, ettringite and AFm are destabilised and the released sulphate is partially incorporated into the C–S–H. The observed changes of the phase assemblage in dependence of the temperature are confirmed by thermodynamic modelling. The increasingly heterogeneous microstructure at elevated temperatures shows an increased density of the C–S–H and a higher coarse porosity. -- Highlights: •The reaction of quartz powder at 80 °C strongly enhances the compressive strength. •Almost no strength increase of fly ash blended OPC at 80 °C was found after 2 days. •Siliceous hydrogarnet is formed upon the reaction of fly ash at high temperatures. •Temperature dependent change of the system was simulated by thermodynamic modelling. •Destabilisation of ettringite above 50 °C correlates with sulphate content of C–S–H.

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

    PubMed

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

    2007-05-01

    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.

  15. Investigating the speciation of copper in secondary fly ash by X-ray absorption spectroscopy.

    PubMed

    Tian, Shulei; Yu, Meijuan; Wang, Wei; Wang, Qi; Wu, Ziyu

    2009-12-15

    Although some researchers have reported that chlorides may play an important part in the evaporation of copper during heat treatment of municipal solid waste incinerators (MSWI) fly ash (1, 2) , details on the copper speciation in volatile matters (secondary fly ash, SFA) are still lacking. In this work, we used in situ X-ray absorption spectroscopy (XAS) experiments involving three types of SFA, which was collected from a high-temperature tubular electric furnace by thermal treatment of municipal solid waste incinerator (MSWI) fly ash at 1000, 1150, and 1250 degrees C. The results obtained by a linear combination fit (LCF) of X-ray absorption near edge structure (XANES) spectra revealed that in MSWI fly ash copper mainly exists as CuO and CuSO(4).5H(2)O while chloride almost dominated all the content of the SFA conformation, which was more than 80%. Extended X-ray absorption fine structure (EXAFS) data analysis indicated the presence of both Cu-O and Cu-Cl bonds in the first coordination shell of Cu ions in all SFA, while only Cu-O bonds occur in the MSWI fly ash. Consequently, in the MSWI fly ash during heat treatment copper evaporated as chloride, and the latter plays an important role in the formation of copper chloride.

  16. Thermal treatment of the fly ash from municipal solid waste incinerator with rotary kiln.

    PubMed

    Wey, Ming-Yen; Liu, Kuang-Yu; Tsai, Tsung-Hsun; Chou, Jing-Tong

    2006-09-21

    Reuse of the fly ash from the municipal solid waste incinerator (MSWI) is a policy of Taiwan EPA. However, the fly ash is often classified as a hazardous waste and cannot be reused directly because the concentrations of heavy metals exceed the TCLP regulations. The main objective of this study is to investigate the continuous sintering behavior of fly ash with a rotary kiln and seek a solution to reduce the concentrations of heavy metal to an acceptable value. The partitions of the heavy metals in the process are also considered. The results of TCLP showed that among the metals of Cr, Cd, Cu and Pb, only the concentrations of Pb in raw fly ash exceeded the regulation. At sintering temperatures of 700, 800 and 900 degrees C, the concentration of Pb decreased in sintering products, however, the concentration of Pb still exceeded the limitation at 700 and 800 degrees C. Additionally, the water-washing was used to pre-treat the fly ash before sintering process. The washing treatment effectively reduced the leaching concentrations of Pb to agree the regulations. Therefore, water-washing followed by a sintering treatment is an available process for detoxifying the fly ash of MSWI.

  17. Erodiblity of fly ash used as a topsoil substitute in mineland reclamation

    SciTech Connect

    Gorman, J.M.; Sencindiver, J.C.; Horvath, D.J.; Singh, R.N.; Keefer, R.F.

    2000-06-01

    Fly ash, a by-product of coal-fired power plants, has been used successfully in reclaiming abandoned mine lands by improving minesoil chemical and physical properties. However, the fine sand-silt particle size of fly ash may make it more susceptible than natural soils to detachment and transport by erosive processes. Furthermore, the high content of silt-size particles in fly ash may make it more susceptible to surface crust formation, resulting in reduced infiltration and increased surface runoff and erosion. In the summer of 1989, fly ash-wood waste mixtures, used as a topsoil substitute, were surface applied on two separate mine sites in Preston County, WV, one with 10% slope and the other 20% slope. Erosion rates were measured directly using the Linear Erosion/Elevation Measuring Instrument (LEMI). Erosion measurements were taken during the first two growing seasons on both sites. Erosion values were up to five times greater on the fly ash-treated minesoil than on the untreated minesoil. Mulching with wood chips reduced fly ash erosion to about one-half the loss of the unmulched plots. Erosion was related to both the amount and type of ground cover. Increased vegetative ground cover resulted in reduced erosion. Mosses and fungi appeared to provide better erosion protection than grass-legume cover.

  18. Geopolymeric adsorbents from fly ash for dye removal from aqueous solution

    SciTech Connect

    Li, L.; Wang, S.B.; Zhu, Z.H.

    2006-08-01

    Adsorbents from coal fly ash treated by a solid-state fusion method using NaOH were prepared. It was found that amorphous aluminosilicate, geopolymers would be formed. These fly ash-derived inorganic polymers were assessed as potential adsorbents for removal of some basic dyes, methylene blue and crystal violet, from aqueous solution. It was found that the adsorption capacity of the synthesised adsorbents depends on the preparation conditions such as NaOH:fly-ash ratio and fusion temperature with the optimal conditions being at 1.2:1 weight ratio of Na:fly-ash at 250-350{sup o}C. The synthesised materials exhibit much higher adsorption capacity than fly ash itself and natural zeolite. The adsorption isotherm can be fitted by Langmuir and Freundlich models while the two-site Langmuir model produced the best results. It was also found that the fly ash derived geopolymeric adsorbents show higher adsorption capacity for crystal violet than methylene blue and the adsorption temperature influences the adsorption capacity. Kinetic studies show that the adsorption process follows the pseudo second-order kinetics.

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

    PubMed Central

    Garcia-Lodeiro, Inés; Donatello, Shane; Fernández-Jiménez, Ana; Palomo, Ángel

    2016-01-01

    In hybrid alkaline fly ash cements, a new generation of binders, hydration, is characterized by features found in both ordinary portland cement (OPC) hydration and the alkali activation of fly ash (AAFA). Hybrid alkaline fly ash cements typically have a high fly ash (70 wt % to 80 wt %) and low clinker (20 wt % to 30 wt %) content. The clinker component favors curing at ambient temperature. A hydration mechanism is proposed based on the authors’ research on these hybrid binders over the last five years. The mechanisms for OPC hydration and FA alkaline activation are summarized by way of reference. In hybrid systems, fly ash activity is visible at very early ages, when two types of gel are formed: C–S–H from the OPC and N–A–S–H from the fly ash. In their mutual presence, these gels tend to evolve, respectively, into C–A–S–H and (N,C)–A–S–H. The use of activators with different degrees of alkalinity has a direct impact on reaction kinetics but does not modify the main final products, a mixture of C–A–S–H and (N,C)–A–S–H gels. The proportion of each gel in the mix does, however, depend on the alkalinity generated in the medium. PMID:28773728

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

    PubMed

    Garcia-Lodeiro, Inés; Donatello, Shane; Fernández-Jiménez, Ana; Palomo, Ángel

    2016-07-22

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

  1. Sulfidation treatment of molten incineration fly ashes with Na2S for zinc, lead and copper resource recovery.

    PubMed

    Kuchar, D; Fukuta, T; Onyango, M S; Matsuda, H

    2007-04-01

    The present study focuses on the conversion of heavy metals involved in molten incineration fly ashes to metal sulfides which could be thereafter separated by flotation. The sulfidation treatment was carried out for five molten incineration fly ashes (Fly ash-A to Fly ash-E) by contacting each fly ash with Na(2)S solution for a period of 10 min to 6h. The initial molar ratio of S(2-) to Me(2+) was adjusted to 1.20. The conversion of heavy metals to metal sulfides was evaluated by measuring the S(2-) residual concentrations using an ion selective electrode. The formation of metal sulfides was studied by XRD and SEM-EDS analyses. In the case of Fly ash-A to Fly ash-D, more than 79% of heavy metals of zinc, lead and copper was converted to metal sulfides within the contacting period of 0.5h owing to a fast conversion of metal chlorides to metal sulfides. By contrast, the conversion of about 35% was achieved for Fly ash-E within the same contacting period, which was attributed to a high content of metal oxides. Further, the S(2-) to Me(2+) molar ratio was reduced to 1.00 to minimize Na(2)S consumption and the conversions obtained within the contacting period of 0.5h varied from 76% for Fly ash-D to 91% for Fly ash-C. Finally, soluble salts such as NaCl and KCl were removed during the sulfidation treatment, which brought about a significant enrichment in metals content by a factor varying from 1.5 for Fly ash-D to 4.9 for Fly ash-A.

  2. Sorption and chemical transformation of PAHs on coal fly ash. Final technical report

    SciTech Connect

    Mamantov, G.; Wehry, E.L.

    1995-02-01

    The objectives of this work were to characterize the interactions of coal fly ash with polycyclic aromatic hydrocarbons (PAH`s) and their derivatives, and to attempt to understand the influence of surface properties of coal ash in the chemical transformations of PAH`s.

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

  4. Role of fly ash in catalytic oxidation of S(IV) slurries

    SciTech Connect

    Cohen, S.; Chang, S.G.; Markowitz, S.S.; Novakov, T.

    1981-12-01

    The rate of catalytic oxidation of S(IV) in aqueous fly-ash slurries has been examined by monitoring loss of SO/sub 2//sup 2 -/ and O/sub 2/ and SO/sub 4//sup 2 -/ formation. Evidence from both filtering and extraction studies indicates that dissolved iron which has been leached from the ash is the chief catalyst. This homogeneous reaction dominates any catalytic effect of the ash surface. 2 figures, 4 tables.

  5. Role of fly ash in catalytic oxidation of sulfur(IV) slurries

    SciTech Connect

    Cohen, Sidney; Chang, Shih Ger.; Markowitz, Samuel S.; Novakov, Tihomir

    1981-12-01

    The rate of catalytic oxidation of S(IV) in aqueous fly ash slurries has been examined by monitoring loss of SO{sub 3}{sup 2-} and O{sub 2}, and SO{sub 4}{sup 2-} formation. Evidence from both filtering and extraction studies indicates that dissolved iron which has been leached from the ash is the chief catalyst. This homogeneous reaction dominates any catalytic effect of the ash surface.

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

    SciTech Connect

    Duangkamol Ruen-ngam; Doungmanee Rungsuk; Ronbanchob Apiratikul; Prasert Pavasant

    2009-10-15

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

  7. Fabrication and adsorption properties of hybrid fly ash composites

    NASA Astrophysics Data System (ADS)

    Gao, Mengfan; Ma, Qingliang; Lin, Qingwen; Chang, Jiali; Ma, Hongzhu

    2017-02-01

    In order to realize the utilization of fly ash (FA) as industrial solid waste better, high-efficient inorganic/organic hybrid composite adsorbents derived from (Ca(OH)2/Na2FeO4) modified FA (MF) was fabricated. The hydrophilic cationic polymer (P(DMDAAC-co-AAM) or hydrophobic modifier (KH-570) were used. The prepared composites were characterized by X-ray fluorescence spectroscopy, energy dispersive spectroscopy, scanning electron microscopy, Brunauer-Emmett-Teller, Fourier transform infrared spectroscopy, thermogravimetry, and contact angle test. The adsorption of cationic composites MF/P(DMDAAC-co-AAM) towards Orange II in wastewater was investigated. The results show that: adsorption amount of 24.8 mg/g with 2000 mg/L of composites, 50 mg/L Orange II, original pH (6-8), at 40 min and room temperature, was obtained. Meanwhile, oil adsorption ratio Q(g/g) of hydrophobic composites MF/KH-570 was also evaluated. The maximum Q of 17.2 g/g to kerosene was obtained at 40 min. The isotherm and kinetics of these two adsorption processes were also studied. The results showed that the fabricated MF composites modified with hydrophilic or hydrophobic group can be used to adsorb dye in wastewater or oil effectively.

  8. Thermal Resistance Variations of Fly Ash Geopolymers: Foaming Responses

    PubMed Central

    Cheng-Yong, Heah; Yun-Ming, Liew; Abdullah, Mohd Mustafa Al Bakri; Hussin, Kamarudin

    2017-01-01

    This paper presents a comparative study of the characteristic of unfoamed and foamed geopolymers after exposure to elevated temperatures (200–800 °C). Unfoamed geopolymers were produced with Class F fly ash and sodium hydroxide and liquid sodium silicate. Porous geopolymers were prepared by foaming with hydrogen peroxide. Unfoamed geopolymers possessed excellent strength of 44.2 MPa and degraded 34% to 15 MPa in foamed geopolymers. The strength of unfoamed geopolymers decreased to 5 MPa with increasing temperature up to 800 °C. Foamed geopolymers behaved differently whereby they deteriorated to 3 MPa at 400 °C and increased up to 11 MPa at 800 °C. Even so, the geopolymers could withstand high temperature without any disintegration and spalling up to 800 °C. The formation of crystalline phases at higher temperature was observed deteriorating the strength of unfoamed geopolymers but enhance the strength of foamed geopolymers. In comparison, foamed geopolymer had better thermal resistance than unfoamed geopolymers as pores provide rooms to counteract the internal damage. PMID:28345643

  9. Fly ash adsorbents for multi-cation wastewater treatment

    NASA Astrophysics Data System (ADS)

    Visa, Maria; Isac, Luminita; Duta, Anca

    2012-06-01

    Class "F" fly ash (FA), collected from the Central Heat and Power (CHP) Plant Brasov (Romania), with oxides composition SiO2/Al2O3 over 2.4 proved good adsorbent properties, and was further used for obtaining a new substrate with good adsorption capacity for heavy metals from multi-cation wastewater treatment. Firstly, the new adsorbent was characterized by AFM, XRD, DSC, FTIR and the surface energy was evaluated by contact angle measurements. The experimental data suggested that the new type of substrate is predominant crystalline with highly polar surface. The substrate was used for removing the Pb2+, Cd2+ and Zn2+ cations from mixed solutions. The results show high efficiency and selective adsorption the Pb2+ and Zn2+ cations. The optimized adsorption parameters were further used in thermodynamic and kinetic studies of the adsorption processes. The Langmuir and Freundlich models were used to describe the processes. The pseudo-second order kinetics could well model all the processes, indicating a surface concentration of the adsorption sites with the same order of magnitude as the cation concentrations.

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

    PubMed

    Ruen-ngam, Duangkamol; Rungsuk, Doungmanee; Apiratikul, Ronbanchob; Pavasant, Prasert

    2009-10-01

    The possibility in converting coal fly ash (CFA) to zeolite was evaluated. CFA samples from the local power plant in Prachinburi province, Thailand, were collected during a 3-month time span to account for the inconsistency of the CFA quality, and it was evident that the deviation of the quality of the raw material did not have significant effects on the synthesis. The zeolite product was found to be type X. The most suitable weight ratio of sodium hydroxide (NaOH) to CFA was approximately 2.25, because this gave reasonably high zeolite yield with good cation exchange capacity (CEC). The silica (Si)-to-aluminum (Al) molar ratio of 4.06 yielded the highest crystallinity level for zeolite X at 79% with a CEC of 240 meq/100 g and a surface area of 325 m2/g. Optimal crystallization temperature and time were 90 degrees C and 4 hr, respectively, which gave the highest CEC of approximately 305 meq/100 g. Yields obtained from all experiments were in the range of 50-72%.

  11. Hydration studies of calcium sulfoaluminate cements blended with fly ash

    SciTech Connect

    García-Maté, M.; De la Torre, A.G.; León-Reina, L.; Aranda, M.A.G.; Santacruz, I.

    2013-12-15

    The main objective of this work is to study the hydration and properties of calcium sulfoaluminate cement pastes blended with fly ash (FA) and the corresponding mortars at different hydration ages. Laboratory X-ray powder diffraction, rheological studies, thermal analysis, porosimetry and compressive strength measurements were performed. The analysis of the diffraction data by Rietveld method allowed quantifying crystalline phases and overall amorphous contents. The studied parameters were: i) FA content, 0, 15 and 30 wt.%; and ii) water addition, water-to-CSA mass ratio (w/CSA = 0.50 and 0.65), and water-to-binder mass ratio (w/b = 0.50). Finally, compressive strengths after 6 months of 0 and 15 wt.% FA [w/CSA = 0.50] mortars were similar: 73 ± 2 and 72 ± 3 MPa, respectively. This is justified by the filler effect of the FA as no strong evidences of reactivity of FA with CSA were observed. These results support the partial substitution of CSA cements with FA with the economic and environmental benefits.

  12. Fly ash-based geopolymer lightweight concrete using foaming agent.

    PubMed

    Al Bakri Abdullah, Mohd Mustafa; Hussin, Kamarudin; Bnhussain, Mohamed; Ismail, Khairul Nizar; Yahya, Zarina; Razak, Rafiza Abdul

    2012-01-01

    In this paper, we report the results of our investigation on the possibility of producing foam concrete by using a geopolymer system. Class C fly ash was mixed with an alkaline activator solution (a mixture of sodium silicate and NaOH), and foam was added to the geopolymeric mixture to produce lightweight concrete. The NaOH solution was prepared by dilute NaOH pellets with distilled water. The reactives were mixed to produce a homogeneous mixture, which was placed into a 50 mm mold and cured at two different curing temperatures (60 °C and room temperature), for 24 hours. After the curing process, the strengths of the samples were tested on days 1, 7, and 28. The water absorption, porosity, chemical composition, microstructure, XRD and FTIR analyses were studied. The results showed that the sample which was cured at 60 °C (LW2) produced the maximum compressive strength for all tests, (11.03 MPa, 17.59 MPa, and 18.19 MPa) for days 1, 7, and 28, respectively. Also, the water absorption and porosity of LW2 were reduced by 6.78% and 1.22% after 28 days, respectively. The SEM showed that the LW2 sample had a denser matrix than LW1. This was because LW2 was heat cured, which caused the geopolymerization rate to increase, producing a denser matrix. However for LW1, microcracks were present on the surface, which reduced the compressive strength and increased water absorption and porosity.

  13. Amelioration of soil PAH and heavy metals by combined application of fly ash and biochar

    NASA Astrophysics Data System (ADS)

    Masto, Reginald; George, Joshy; Ansari, Md; Ram, Lal

    2016-04-01

    Generation of electricity through coal combustion produces huge quantities of fly ash. Sustainable disposal and utilization of these fly ash is a major challenge. Fly ash along with other amendments like biochar could be used for amelioration of soil. In this study, fly ash and biochar were used together for amelioration of polycyclic aromatic hydrocarbon (PAH) contaminated soil. Field experiment was conducted to investigate the effects of fly ash and biochar on the amelioration of soil PAH, and the yield of Zea mays. The treatments were control, biochar (4 t/ha), fly ash (4 t/ha), ash + biochar ( 2 + 2 t/ha). Soil samples were collected after the harvest of maize crop and analysed for chemical and biological parameters. Thirteen PAHs were analysed in the postharvest soil samples. Soil PAHs were extracted in a microwave oven at 120 °C using hexane : acetone (1:1) mixture. The extracted solutions were concentrated, cleaned and the 13 PAHs [Acenaphthene (Ace), fluorene (Flr), phenanthrene (Phn), anthracene(Ant), pyrene(Pyr), benz(a)anthracene (BaA), chrysene (Chy), benzo(b)fluoranthene (BbF), benzo(k)fluoranthene (BkF), benzo(a)pyrene, benzo(g,h,i)perylene (BghiP), dibenzo(a,h)anthracene, and indeno(1,2,3-cd)pyrene)(Inp)] were analysed using GC-MS. The mean pH increased from 6.09 in control to 6.64 and 6.58 at biochar and fly ash treated soils, respectively. N content was not affected, whereas addition of biochar alone and in combination with fly ash, has significantly increased the soil organic carbon content. P content was almost double in combined (9.06 mg/kg) treatment as compared to control (4.32 mg/kg). The increase in K due to biochar was 118%, whereas char + ash increased soil K by 64%. Soil heavy metals were decreased: Zn (-48.4%), Ni (-41.4%), Co (-36.9%), Cu (-35.7%), Mn (-34.3%), Cd (-33.2%), and Pb (-30.4%). Soil dehydrogenase activity was significantly increased by ash and biochar treatments and the maximum activity was observed for the combined

  14. Thermal decomposition of municipal solid waste fly ash and desorption of polychlorinated dibenzo-p-dioxins and furans from fly ash surfaces.

    PubMed

    Weidemann, Eva; Lundin, Lisa; Boily, Jean-François

    2016-11-01

    Surfaces of fly ashes from three Swedish MSW incinerating plants were extensively characterized to better predict their involvement in the generation of persistent organic pollutants. The ashes were then subjected to thermal treatment at 400 °C in sealed glass ampoules to track the decomposition polychlorinated dibenzo-p-dioxins and furans (PCDD and PCDF). Temperature programmed desorption experiments in the 30-900 °C range also enabled monitoring of thermally decomposing ashes by Fourier Transform Infrared (FTIR) spectroscopy as well as thermally desorbing effluent gases by mass spectrometry. In addition, one ash was doped with (13)C-labelled PCDD and PCDF to evaluate the potential of the experimental setup for elucidating the thermal desorption of the organic molecules. It was found that in ashes with high carbon content PCDD and PCDF decomposition were led pronounced, and that PCDD degraded more readily than PCDF.

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

    PubMed

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

    2012-08-01

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

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

    PubMed

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

    2014-12-01

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

  17. Chemical Fixation of Trace Elements in Coal Fly Ash using Ferrous Sulfate Treatment

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, S.; Donahoe, R. J.

    2008-12-01

    Coal fired electric power plants produce 50% of the electricity consumed in the US and generate large volumes of fly ash and other coal combustion by-products (CCBs). The majority of the CCB materials are disposed of in surface impoundments and landfills located throughout the US. Fly ash contains trace elements such as As, B, Cr, Mo, Ni, Se, Sr and V which can have a negative impact on the environment due to leaching by acid rain and groundwater with time. The potential release of these toxic trace elements into the environment is a big concern for the US power industry due to the high cost involved in lining the old and existing ash disposal sites. As a result, simple and effective treatment techniques are needed to stabilize the coal combustion by-products produced by power plants in the ash disposal sites and also to increase the use of coal fly ash for beneficial purposes. This paper reports the results of batch experiments designed to chemically treat coal fly ash with ferrous sulfate solution by promoting the formation of insoluble iron oxy- hydroxide phases that immobilize the toxic trace elements. Four fly ash samples, three acidic (HA, HB and MA) and one alkaline (PD), were treated with a ferrous sulfate (FS) solution (322 ppm Fe) and a ferrous sulfate + calcium carbonate (FS+CC) solution (322 ppm Fe and 28 ppm CaCO3) at solid:liquid ratios of 1:3 and 1:30. The effectiveness of this treatment technique was evaluated by the batch sequential leaching of treated and untreated coal fly ash samples using a synthetic acid rain (SAR) solution (USEPA Method 1312B) and also by a 7-step sequential chemical extraction procedure (SCEP) to understand the mechanism of treatment. The unbuffered FS solution at the 1:30 ratio was highly successful in reducing the mobility of the oxyanionic trace elements As (24-91%), Cr (82-97%), Mo (79-100%), Se (41-87%) and V (55-100%). However, the unbuffered FS treatment failed to reduce the mobility of B, Ni and Sr for the acidic fly

  18. Automated system for removal and pneumatic transport of fly ash from electric precipitator hoppers

    SciTech Connect

    V.K. Konovalov; O.V. Yashkin; V.V. Ermakov

    2008-03-15

    A system for removal and pneumatic transport of fly ash is examined, in which air pulses act on batches (pistons) of ash formed in a duct. Studies are made of the effect of several physical parameters on the force required to displace a piston of ash and these serve as a basis for choosing a system for removal and pneumatic transport of ash simultaneously from several hoppers of an electric precipitator. This makes it possible to separate the ash particles according to size without introducing additional components. Formulas are given for calculating the structural and dynamic parameters of this system and measurements of indirect dynamic parameters are used to calculate the input-output characteristics of the system. In order to optimize the system, configurations for summing several ducts into a single transport duct for pneumatic ash transport are proposed. Some variants of dry ash utilization and the advantages of producing of size-separated particles are considered.

  19. Beyond waste: new sustainable fillers from fly ashes stabilization, obtained by low cost raw materials.

    PubMed

    Rodella, N; Pasquali, M; Zacco, A; Bilo, F; Borgese, L; Bontempi, N; Tomasoni, G; Depero, L E; Bontempi, E

    2016-09-01

    A sustainable economy can be achieved only by assessing processes finalized to optimize the use of resources. Waste can be a relevant source of energy thanks to energy-from-waste processes. Concerns regarding the toxic fly ashes can be solved by transforming them into resource as recycled materials. The commitment to recycle is driven by the need to conserve natural resources, reduce imports of raw materials, save landfill space and reduce pollution. A new method to stabilize fly ash from Municipal Solid Waste Incinerator (MSWI) at room temperature has been developed thanks to COSMOS-RICE LIFE+ project (www.cosmos-rice.csmt.eu). This process is based on a chemical reaction that occurs properly mixing three waste fly ashes with rice husk ash, an agricultural by-product. COSMOS inert can replace critical raw materials (i.e. silica, fluorspar, clays, bentonite, antimony and alumina) as filler. Moreover the materials employed in the stabilization procedure may be not available in all areas. This paper investigates the possibility of substituting silica fume with corresponding condensed silica fume and to substitute flue-gas desulfurization (FGD) residues with low-cost calcium hydroxide powder. The removal of coal fly ash was also considered. The results will be presented and a possible substitution of the materials to stabilize fly ash will be discussed.

  20. Stabilization and separation of heavy metals in incineration fly ash during the hydrothermal treatment process.

    PubMed

    Hu, Yuyan; Zhang, Pengfei; Li, Jianping; Chen, Dezhen

    2015-12-15

    In the paper, hydrothermal treatment (HT) of MSWI fly ashes was performed to stabilize and separate heavy metals. Influences of pre-treatment, types of ferric and/or ferrous additives, and subsequent heavy metal stabilization procedure by adding phosphate were investigated. The chemical stability of hydrothermal products was examined by solid waste extraction procedure with acetic acid buffer solution. Mineralogical investigation of selected hydrothermal product was carried out by XRD. FEGE SEM- -EDX was used to study the morphology and surface compositions of the ash particles. Experimental results revealed that HT process facilitated heavy metal exposure to leaching solution. FEGE SEM-EDX images revealed that fly ash particles were re-organized during hydrothermal process and that the minerals with special shapes and containing high levels of heavy metals were formed. A mild acid washing treatment with final pH around 6.20 could remove soluble heavy metals. Therefore, it may be a proper pre- or post-treatment method for fly ash particles for the purpose of reducing heavy metal contents. For the purpose of stabilizing heavy metals, the addition of ferric/ferrous salts in the HT process or phosphate stabilization after HT is recommended. The HT process may be applied to realize the environmentally sound management of MSWI fly ash or to recover and utilize MSWI fly ash. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. EFFECTS OF FLY ASH ON MERCURY OXIDATION DURING POST COMBUSTION CONDITIONS

    SciTech Connect

    Glenn A. Norton

    1999-10-01

    Tests were performed in simulated flue gas streams using two fly ash samples from the electrostatic precipitators of two full-scale utility boilers. One fly ash was derived from a Powder River Basin (PRB) coal, while the other was derived from Blacksville coal (Pittsburgh No. 8 seam). The tests were performed at temperatures of 120 and 180 C under different gas compositions. Elemental mercury (Hg) streams were injected into the simulated flue gas and passed over filters (housed in a convection oven) loaded with fly ash. The Ontario Hydro method was used to determine the total amount of Hg passing through the filter as well as the percentages of elemental and oxidized Hg collected. Results indicated that substantial amounts of Hg oxidation did not occur with either fly ash, regardless of the temperature used for testing. When oxidation was observed, the magnitude of the oxidation was comparable between the two fly ashes. These results suggest that the gas matrix may be more important than the ash components with respect to the distribution of Hg species observed in gaseous effluents at coal-fired power plants.

  2. Comparing Metal Leaching and Toxicity from High pH, Low pH, and High Ammonia Fly Ash

    SciTech Connect

    Palumbo, Anthony Vito; Phillips, Jana Randolph; Fagan, Lisa Anne; Drake, Meghan M; Ruther, Rose Emily; Fisher, L. Suzanne; Amonette, J. E.

    2007-01-01

    Previous work with both class F and class C fly ash indicated minimal leaching from most fly ashes tested. However, the addition of NOx removal equipment might result in higher levels of ammonia in the fly ash. We have recently been testing fly ash with a wide range of pH (3.7-12.4) originating from systems with NOx removal equipment. Leaching experiments were done using dilute CaCl2 solutions in batch and columns and a batch nitric acid method. All methods indicated that the leaching of heavy metals was different in the highest ammonia sample tested and the high pH sample. However, toxicity testing with the Microtox system has indicated little potential toxicity in leachates except for the fly ash at the highest pH (12.4). When the leachate from the high pH fly ash was neutralized, toxicity was eliminated.

  3. Comparing metal leaching and toxicity from high pH, low pH, and high ammonia fly ash

    SciTech Connect

    Palumbo, Anthony V.; Tarver, Jana R.; Fagan, Lisa A.; McNeilly, Meghan S.; Ruther, Rose; Fisher, L. S.; Amonette, James E.

    2007-07-01

    Previous work with both class F and class C fly ash indicated minimal leaching from most fly ashes tested. However, the addition of NOx removal equipment might result in higher levels of ammonia in the fly ash. We have recently been testing fly ash with a wide range of pH (3.7–12.4) originating from systems with NOx removal equipment. Leaching experiments were done using dilute CaCl2 solutions in batch and columns and a batch nitric acid method. All methods indicated that the leaching of heavy metals was different in the highest ammonia sample tested and the high pH sample. However, toxicity testing with the Microtox* system has indicated little potential toxicity in leachates except for the fly ash at the highest pH (12.4). When the leachate from the high pH fly ash was neutralized, toxicity was eliminated.

  4. Fly-ash products from biomass co-combustion for VOC control.

    PubMed

    Kwong, C W; Chao, C Y H

    2010-02-01

    Experiments were conducted in a continuous flow reactor at room temperature to evaluate the elimination of low-concentration toluene in the gas phase to verify if fly-ash products from biomass combustion in an ozonation system could be used in the removal of volatile organic compounds. The fly-ash products from pure biomass combustion (Ash(100)) demonstrated the highest ozonation activities upon the removal of low-concentration toluene (1.5 ppmv), followed by the fly-ash products from co-combustion (Ash(30)) and the coal combustion (Ash(0)). Kinetic experiments showed that the activation energy of the toluene elimination process was substantially reduced with the use of ozone and the reaction intermediates, such as formic acids, aldehydes, etc. Results also showed that the intermediates were reduced with increasing humidity level. The combined use of fly-ash products and zeolite 13X enhanced the removal of toluene to above 90% and suppressed the release of residual ozone and intermediates by holding them in the adsorbed phase.

  5. Release and bioavailability of zinc and heavy metals in fly ash amended soil and mine spoil

    SciTech Connect

    Elmosly, W.A.

    1990-01-01

    Heavy metals concentrations were estimated in an acid Zn deficient soil (Clymer) and a pyritic acid mine spoil (Lenox) treated with three fly ashes at rates of 0, 33, and 66% after incubation at field capacity, saturation, and cycles of wetting, leaching, and drying. Metals were extracted with DTPA, HCl, Mehlich 3, MgCl[sub 2], ammonium acetate, and H[sub 2]O. Incorporation of alkaline fly ashes into both soils significantly increased soil pH. Extractability of all metals depended on pH of the soil-ash mixtures, characteristics of soils and ashes, and nature of the extractant. Moisture only affected extractability of Cr, Fe, and Mn. Zinc levels were increased in the Clymer soil but decreased in the Lenox spoil. Water solubility of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn was determined on three alkaline fly ashes. A greenhouse study with two successive corn crops was conducted to determine yield, plant availability of Zn, and uptake of heavy metals in the plant tops grown on Clymer and Lenox soils treated with three fly ashes at rates of 0, 33, 66%. Fly ash addition usually caused: (a) corn tops yield depression, especially for the second crop, (b) increase in plant Zn concentration on Zn-deficient Clymer soil, (c) decrease in Mn toxicity on Lenox spoil, and (d) increase in Cd, Co, Cr, Cu, Ni, and Pb plants. The high concentrations of these metals in corn tissues may have been due to stunted growth. Quality of the soil environment by heavy fly ash additions has been shown to be improved with respect to plant nutrition of Zn and Mn, but may have deteriorated by increase in heavy metals.

  6. Effect of Fly Ash and Silica Fume on the Mechanical Properties of Cement Paste at Different Stages of Hydration

    DTIC Science & Technology

    2015-08-10

    Different Stages of Hydration Report Title This thesis investigates the effect of fly ash and silica fume on cement paste hydration. Percentages of each...Additional figures were created to compare the different curing days against the change in fly ash percentages that can be found in Appendix D. Figure 4.4...cured samples. The controlled cement paste was used as a reference in comparing fly ash or silica fume percentages and the different methods of curing

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

    PubMed Central

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

    2013-01-01

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

  8. Chemical associations and mobilization of heavy metals in fly ash from municipal solid waste incineration.

    PubMed

    Weibel, Gisela; Eggenberger, Urs; Schlumberger, Stefan; Mäder, Urs K

    2016-12-19

    This study focusses on chemical and mineralogical characterization of fly ash and leached filter cake and on the determination of parameters influencing metal mobilization by leaching. Three different leaching processes of fly ash from municipal solid waste incineration (MSWI) plants in Switzerland comprise neutral, acidic and optimized acidic (+ oxidizing agent) fly ash leaching have been investigated. Fly ash is characterized by refractory particles (Al-foil, unburnt carbon, quartz, feldspar) and newly formed high-temperature phases (glass, gehlenite, wollastonite) surrounded by characteristic dust rims. Metals are carried along with the flue gas (Fe-oxides, brass) and are enriched in mineral aggregates (quartz, feldspar, wollastonite, glass) or vaporized and condensed as chlorides or sulphates. Parameters controlling the mobilization of neutral and acidic fly ash leaching are pH and redox conditions, liquid to solid ratio, extraction time and temperature. Almost no depletion for Zn, Pb, Cu and Cd is achieved by performing neutral leaching. Acidic fly ash leaching results in depletion factors of 40% for Zn, 53% for Cd, 8% for Pb and 6% for Cu. The extraction of Pb and Cu are mainly limited due to a cementation process and the formation of a PbCu(0)-alloy-phase and to a minor degree due to secondary precipitation (PbCl2). The addition of hydrogen peroxide during acidic fly ash leaching (optimized acidic leaching) prevents this reduction through oxidation of metallic components and thus significantly higher depletion factors for Pb (57%), Cu (30%) and Cd (92%) are achieved. The elevated metal depletion using acidic leaching in combination with hydrogen peroxide justifies the extra effort not only by reduced metal loads to the environment but also by reduced deposition costs.

  9. Thermal and hydrometallurgical recovery methods of heavy metals from municipal solid waste fly ash

    SciTech Connect

    Kuboňová, L.

    2013-11-15

    Highlights: • MSW fly ash was thermally and hydrometallurgically treated to remove heavy metals. • More than 90% of easy volatile heavy metals (Cd and Pb) were removed thermally. • More than 90% of Cd, Cr, Cu an Zn were removed by alkaline – acid leaching. • The best results were obtained for the solution of 3 M NaOH and 2 M H{sub 2}SO{sub 4}. - Abstract: Heavy metals in fly ash from municipal solid waste incinerators are present in high concentrations. Therefore fly ash must be treated as a hazardous material. On the other hand, it may be a potential source of heavy metals. Zinc, lead, cadmium, and copper can be relatively easily removed during the thermal treatment of fly ash, e.g. in the form of chlorides. In return, wet extraction methods could provide promising results for these elements including chromium and nickel. The aim of this study was to investigate and compare thermal and hydrometallurgical treatment of municipal solid waste fly ash. Thermal treatment of fly ash was performed in a rotary reactor at temperatures between 950 and 1050 °C and in a muffle oven at temperatures from 500 to 1200 °C. The removal more than 90% was reached by easy volatile heavy metals such as cadmium and lead and also by copper, however at higher temperature in the muffle oven. The alkaline (sodium hydroxide) and acid (sulphuric acid) leaching of the fly ash was carried out while the influence of temperature, time, concentration, and liquid/solid ratio were investigated. The combination of alkaline-acidic leaching enhanced the removal of, namely, zinc, chromium and nickel.

  10. Performance evaluation of cement stabilized fly ash-GBFS mixes as a highway construction material.

    PubMed

    Singh, S P; Tripathy, D P; Ranjith, P G

    2008-01-01

    Fly ash and granulated blast furnace slag (GBFS) are major by-products of thermal and steel plants, respectively. These materials often cause disposal problems and environmental pollution. Detailed laboratory investigations were carried out on cement stabilized fly ash-(GBFS) mixes in order to find out its suitability for road embankments, and for base and sub-base courses of highway pavements. Proctor compaction test, unconfined compressive strength (UCS) test and California Bearing Ratio (CBR) test were conducted on cement stabilized fly ash-GBFS mixes as per the Indian Standard Code of Practice. Cement content in the mix was varied from 0% to 8% at 2% intervals, whereas the slag content was varied as 0%, 10%, 20%, 30% and 40%. Test results show that an increase of either cement or GBFS content in the mixture, results in increase of maximum dry density (MDD) and decrease of optimum moisture content (OMC) of the compacted mixture. The MDD of the cement stabilized fly ash-GBFS mixture is comparably lower than that of similarly graded natural inorganic soil of sand to silt size. This is advantageous in constructing lightweight embankments over soft, compressible soils. An increase in percentage of cement in the fly ash-GBFS mix increases enormously the CBR value. Also an increase of the amount of GBFS in the fly ash sample with fixed cement content improves the CBR value of the stabilized mix. In the present study, the maximum CBR value of compacted fly ash-GBFS-cement (52:40:8) mixture obtained was 105%, indicating its suitability for use in base and sub-base courses in highway pavements with proper combinations of raw materials.

  11. Chemical evaluation of nutrient supply from fly ash-biosolids mixtures

    SciTech Connect

    Schumann, A.W.; Sumner, M.E.

    2000-02-01

    Prediction of plant nutrient supply from fly ash and biosolids (sewage sludge and poultry manure) may enhance their agricultural use as crop fertilizer. Two mild extraction methods (42-d equilibration with ion-exchange resins; 2-d equilibration with pH 4.8 buffered nutrient solution) and analysis of nutrient data by the Diagnosis and Recommendation Integrated System (DRIS) were tested with 29 fly ash samples, four biosolids samples, and their mixtures. The resin method was useful for major nutrient (N, P, K, Ca, Mg, S) extraction from fly ashes and organic materials, particularly where mineralizable fractions of N and P under aerobic conditions are required. However, resins were inefficient in extracting P from high-Fe sewage sludges because organic waste samples caused premature failure of semipermeable membranes and fouling of resins. Extraction of fly ash with dilute buffered nutrient solution was more successful because micronutrient recovery was improved, major nutrients were correlated to the resin method, both addition and removal of nutrients were recorded. DRIS analysis was possible, and equilibration was rapid (2 d). The overall nutrient supply from these extremely variable fly ashes was: Cu = Fe {approx} B {approx} Mo > Ca > S > Zn >> Mn > N > Mg > P > K (high micronutrient, low major nutrient supply). For biosolids, the major nutrients ranked: P > N {approx} Ca > S > Mg > K (sewage sludges), and N > Ca {approx} K > P > Mg > S (poultry manures). In mixtures of fly ash with 26% sewage sludge the order was: Ca > S > N > Mg > P > K, while in mixtures of fly ash and 13% poultry manure, the nutrients ranked: Ca > K {approx} N {approx} S > Mg > P. Optimal plant nutrition (especially N-P-K balancing) should be possible by mixing these three waste materials.

  12. Removal of phosphate from aqueous solution by zeolite synthesized from fly ash.

    PubMed

    Chen, Jiangang; Kong, Hainan; Wu, Deyi; Hu, Zhanbo; Wang, Zaosheng; Wang, Yanhua

    2006-08-15

    Fifteen Chinese fly ashes were converted hydrothermally into zeolites, and phosphate immobilization capacity (PIC) of the synthesized zeolites and the corresponding raw fly ashes were determined using an initial phosphate concentration of 1000 mg/L. Results showed that there was a remarkable increase in PIC (from 1.2 to 7.6 times) following the synthesis process. Fractionation of immobilized phosphorus indicated that Fe+Al-P increased most significantly and consistently among all the phosphorus fractions following the conversion of fly ash to zeolite. The PIC and Ca+Mg-P were closely related to Ca content (with r values of 0.9683 and 0.9651, respectively) rather than Mg content (with r values of 0.3920 and 0.3212, respectively). The r values of PIC and Fe+Al-P with Fe content (with r values of 0.4686 and 0.6385, respectively) were higher than those with Al content (with r values of -0.7857 and -0.3770, respectively). Although calcium and iron components were mainly involved in phosphate immobilization, there was no significant change of Ca and Fe content following the conversion of fly ash to zeolite. Increase in dissociated Fe(2)O(3) and specific surface area probably accounted for the enhancement in PIC of synthesized zeolites compared with corresponding fly ashes. The PIC value of zeolites showed a significant correlation with dissociated Fe(2)O(3) (r=0.6186). The specific surface area increased 26.0-89.4 times as a result of the conversion of fly ash to zeolite. The maximum removal of phosphate occurred within different pH ranges for zeolites which were synthesized from high, medium and low calcium fly ashes and this behavior was explained by the reaction of phosphate with calcium and iron components.

  13. The use of fly ash the thermal power plants in the construction

    NASA Astrophysics Data System (ADS)

    Fediuk, R. S.; Yushin, A. M.

    2015-10-01

    The problems of ecological and radiation safety of the construction of man-made waste like fly ash thermal power plants were researched. The chemical composition of TPPs ashes of Primorsky Territory was studied, defined their specific effective activity of natural radionuclides. The most modern research methods were used - differential thermal analysis, thermogravimetry, X-ray analysis. It was revealed that the ash of the Primorskaya TPP and Partizanskaya TPP has exceed the permissible parameters of radioactivity, so not suitable for use in construction. Ashes of Vladivostok TPP-2 and Artem TPP of Primorsky Region on parameters radioactivity and chemical composition have suitable for use as a filler in the concrete.

  14. Flocculation of cyanobacterial cells using coal fly ash modified chitosan.

    PubMed

    Yuan, Yuting; Zhang, Honggang; Pan, Gang

    2016-06-15

    Harmful algal blooms (HABs) have increasingly occurred worldwide and pose serious threats to water environment safety. In this study, a compound flocculant (CFAL-Chitosan) was developed for HABs mitigation where chitosan was modified by coal fly ash leachate (CFAL). When using optimized dosage of CFAL-Chitosan flocculant, the zeta potential of Microcystis aeruginosa (M.A.) flocs stayed close to zero and algal removal efficiency plateaued over 90% in a wide dosage range from 3 to 6 mg L(-1). For chitosan without CFAL, removal efficiency peaked at 3 mg L(-1) with a maximum removal efficiency of 81%, which quickly decreased as the dosage increased (>3 mg L(-1)) due to the fast reversal of zeta potential. This indicated that CFAL-Chitosan could maintain a better removal efficiency over a wide dosage range as a result of improved charge neutralization compared with the chitosan only treatment. The flocs of CFAL-Chitosan were larger and denser than produced in the presence of chitosan without CFAL. However, excessive CFAL beyond the optimized dose inhibited M.A. removal due to hydrolysis and declining molecular weight of chitosan that weakened the bridging-netting properties, where surface charge reversal happened within a narrow dosage range and the removal-dosage curve became parabolic. The pH and metal residuals that were assumed to pose a threat to the aquatic environment were not significantly affected by adding optimized dosage of CFAL-Chitosan. The study provides a HABs control method using a cheap material of CFA. Further studies are needed to check the potential influence of leachable metals and persistent organic pollutants in CFA under a wide range of environmental condition.

  15. Fly Ash-based Geopolymer Lightweight Concrete Using Foaming Agent

    PubMed Central

    Al Bakri Abdullah, Mohd Mustafa; Hussin, Kamarudin; Bnhussain, Mohamed; Ismail, Khairul Nizar; Yahya, Zarina; Razak, Rafiza Abdul

    2012-01-01

    In this paper, we report the results of our investigation on the possibility of producing foam concrete by using a geopolymer system. Class C fly ash was mixed with an alkaline activator solution (a mixture of sodium silicate and NaOH), and foam was added to the geopolymeric mixture to produce lightweight concrete. The NaOH solution was prepared by dilute NaOH pellets with distilled water. The reactives were mixed to produce a homogeneous mixture, which was placed into a 50 mm mold and cured at two different curing temperatures (60 °C and room temperature), for 24 hours. After the curing process, the strengths of the samples were tested on days 1, 7, and 28. The water absorption, porosity, chemical composition, microstructure, XRD and FTIR analyses were studied. The results showed that the sample which was cured at 60 °C (LW2) produced the maximum compressive strength for all tests, (11.03 MPa, 17.59 MPa, and 18.19 MPa) for days 1, 7, and 28, respectively. Also, the water absorption and porosity of LW2 were reduced by 6.78% and 1.22% after 28 days, respectively. The SEM showed that the LW2 sample had a denser matrix than LW1. This was because LW2 was heat cured, which caused the geopolymerization rate to increase, producing a denser matrix. However for LW1, microcracks were present on the surface, which reduced the compressive strength and increased water absorption and porosity. PMID:22837687

  16. Effect of fly ash on the optimum sulfate of Portland Cement

    NASA Astrophysics Data System (ADS)

    Niemuth, Mark D.

    Calcium sulfate is typically added to ordinary portland cement (OPC) clinker during grinding to prevent flash set and to improve early-age strength development without causing volume instabilities. Recent changes to ASTM C150, Standard Specification for Portland Cement, have enabled greater flexibility in determining optimum sulfate levels in portland cement by not requiring ASTM C563, Approximation of Optimum SO3 in Hydraulic Cement Using Compressive Strength, to be used in setting sulfate target levels. ASTM C563 requires strength testing using only the hydraulic cement, which is not always indicative of the optimum sulfate for field use, since supplementary materials (e.g., fly ash) may be used by the concrete producer. Adding additional sulfate to account for the sulfate demand of fly ashes can enable an improvement in the early age strength for cement-fly ash systems and decrease in problems that may be attributed to OPC-admixture-fly ash incompatibility such as abnormal setting and slow strength gain. This thesis provides experimental data on the strength development and heat release during early hydration for cement-fly ash systems with different sulfate levels. The thesis focused on high calcium fly ashes, but low calcium fly ash was also tested. It is demonstrated that some fly ashes have their own sulfate demand and when these ashes are used in cement-fly ash blends there is effectively an increase in the optimal sulfate level that could be used for the OPC. It is also shown that optimum sulfate determined by heat of hydration measured with isothermal calorimetry is similar to the optimum sulfate determined by compressive strength at 1 day. Using isothermal calorimetry can result in substantial time and cost savings at plants for determining the optimal sulfate content. Theories for the mechanisms that drive the differences in sulfate demand in OPC are reviewed. These theories are adapted for OPC-fly ash blends and are outlined, tested and discussed. The

  17. Intra- and inter-unit variation in fly ash petrography and mercury adsorption: Examples from a western Kentucky power station

    USGS Publications Warehouse

    Hower, J.C.; Finkelman, R.B.; Rathbone, R.F.; Goodman, J.

    2000-01-01

    Fly ash was collected from eight mechanical and 10 baghouse hoppers at each of the twin 150-MW wall-fired units in a western Kentucky power station. The fuel burned at that time was a blend of many low-sulfur, high-volatile bituminous Central Appalachian coals. The baghouse ash showed less variation between units than the mechanical hoppers. The mechanical fly ash, coarser than the baghouse ash, showed significant differences in the amount of total carbon and in the ratio of isotropic coke to both total carbon and total coke - the latter excluding inertinite and other unburned, uncoked coal. There was no significant variation in proportions of inorganic fly ash constituents. The inter-unit differences in the amount and forms of mechanical fly ash carbon appear to be related to differences in pulverizer efficiency, leading to greater amounts of coarse coal, therefore unburned carbon, in one of the units. Mercury capture is a function of both the total carbon content and the gas temperature at the point of fly ash separation, mercury content increasing with an increase in carbon for a specific collection system. Mercury adsorption on fly ash carbon increases at lower flue-gas temperatures. Baghouse fly ash, collected at a lower temperature than the higher-carbon mechanically separated fly ash, contains a significantly greater amount of Hg.

  18. Effects of different surface modification and contents on municipal solid waste incineration fly ash/epoxy composites.

    PubMed

    Goh, C K; Valavan, S E; Low, T K; Tang, L H

    2016-12-01

    Incineration fly ash, a waste from municipal solid waste incineration plant can be used to replace conventional filler as reinforcing filler to enhance the mechanical strength of a composite. Surface modification was performed on the incineration fly ash before mixing into the soft polymer matrix so as to improve interfacial bond of the filler and epoxy resin. In this study, detailed characterisation of mechanical, morphological and leaching behaviours of municipal solid waste incineration (MSWI) fly ash infused composite has been carried out. Flexural and tensile test was conducted to determine the effect on mechanical properties of the composite by varying the concentration of incineration fly ash filler added into polymer matrix and surface modification of incineration fly ash filler using silane coupling agent and colloidal mesoporous silica (CMS). The results indicated that composite infused with incineration fly ash filler surface treated with CMS shown improvement on the tensile and flexural strengths. In addition, SEM images showed that surface modification of incineration fly ash with colloidal mesoporous silica enhanced the interfacial bonding with polymer resin which explained the improvement of mechanical strength. Leaching test showed result of toxic metals such as Pb, Zn, Fe, Cu, Cr, Cd and Rb immobilised in the polymer matrix of the composite. Hence, the use of MSWI fly ash as reinforcing filler in the composite appears green and sustainable because this approach is a promising opportunity to substitute valuable raw material with MSWI fly ash. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Geochemically structural characteristics of municipal solid waste incineration fly ash particles and mineralogical surface conversions by chelate treatment.

    PubMed

    Kitamura, Hiroki; Sawada, Takaya; Shimaoka, Takayuki; Takahashi, Fumitake

    2016-01-01

    Leaching behaviors of heavy metals contained in municipal solid waste incineration (MSWI) fly ash have been studied well. However, micro-characteristics of MSWI fly ash particles are still uncertain and might be non-negligible to describe their leaching behaviors. Therefore, this study investigated micro-characteristics of MSWI fly ash particles, especially their structural properties and impacts of chelate treatment on surface characteristics. According to SEM observations, raw fly ash particles could be categorized into four types based on their shapes. Because chelate treatment changed the surface of fly ash particles dramatically owing to secondary mineral formations like ettringite, two more types could be categorized for chelate-treated fly ash particles. Acid extraction experiments suggest that fly ash particles, tested in this study, consist of Si-base insoluble core structure, Al/Ca/Si-base semi-soluble matrices inside the body, and KCl/NaCl-base soluble aggregates on the surface. Scanning electron microscope (SEM) observations of the same fly ash particles during twice moistening treatments showed that KCl/NaCl moved under wet condition and concentrated at different places on the particle surface. However, element mobility depended on secondary mineral formations. When insoluble mineral like gypsum was generated and covered the particle surface, it inhibited element transfer under wet condition. Surface characteristics including secondary mineral formation of MSWI fly ash particles are likely non-negligible to describe trace element leaching behaviors.

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

    PubMed

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

    2014-05-01

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

  1. Fly ash design manual for road and site applications. Volume 1, Dry or conditioned placement: Final report

    SciTech Connect

    DiGioia, A.M. Jr.; Brendel, G.F.

    1992-04-01

    This design manual describes the use of fly ash as a construction material for use as structural and nonstructural fills, backfills, embankments, base courses, roller compacted concrete dams and pavements, soil stabilization, land reclamation and other high volume uses. The manual details the physical, engineering, and chemical properties of bituminous, subbituminous and lignite fly ash. Included are field and laboratory testing methods, design data, procedures and examples, specifications, quality control, and pre- and post-construction monitoring. Volume 1 describes uses where fly ash is used dry or conditioned with small amounts of moisture. Volume 2 describes uses where fly ash is placed as a slurry with relatively large amounts of water.

  2. Reclamation and revegetation of fly ash disposal sites - Challenges and research needs.

    PubMed

    Haynes, R J

    2009-01-01

    Coal-fired power generation is a principal energy source throughout the world. Approximately, 70-75% of coal combustion residues are fly ash and its utilization worldwide is only slightly above 30%. The remainder is disposed of in landfills and fly ash basins. It is desirable to revegetate these sites for aesthetic purposes, to stabilize the surface ash against wind and water erosion and to reduce the quantity of water leaching through the deposit. Limitations to plant establishment and growth in fly ash can include a high pH (and consequent deficiencies of Fe, Mn, Cu, Zn and P), high soluble salts, toxic levels of elements such as B, pozzalanic properties of ash resulting in cemented/compacted layers and lack of microbial activity. An integrated organic/biotechnological approach to revegetation seems appropriate and should be investigated further. This would include incorporation of organic matter into the surface layer of ash, mycorrhizal inoculation of establishing vegetation and use of inoculated legumes to add N. Leaching losses from ash disposal sites are likely to be site-specific but a sparse number of studies have revealed enriched concentrations of elements such as Ca, Fe, Cd, Pb, and Sb in surrounding groundwater. This aspect deserves further study particularly in the longer-term. In addition, during weathering of the ash and deposition of organic matter during plant growth, a soil will form with properties vastly different to that of the parent ash. In turn, this will influence the effect that the disposal site has on the surrounding environment. Nevertheless, the effects of ash weathering and organic matter accumulation over time on the chemical, physical and biological properties of the developing ash-derived soil are not well understood and require further study.

  3. Recovery of soluble chloride salts from the wastewater generated during the washing process of municipal solid wastes incineration fly ash.

    PubMed

    Tang, Hailong; Erzat, Aris; Liu, Yangsheng

    2014-01-01

    Water washing is widely used as the pretreatment method to treat municipal solid waste incineration fly ash, which facilitates the further solidification/stabilization treatment or resource recovery of the fly ash. The wastewater generated during the washing process is a kind of hydrosaline solution, usually containing high concentrations of alkali chlorides and sulphates, which cause serious pollution to environment. However, these salts can be recycled as resources instead of discharge. This paper explored an effective and practical recovery method to separate sodium chloride, potassium chloride, and calcium chloride salts individually from the hydrosaline water. In laboratory experiments, a simulating hydrosaline solution was prepared according to composition of the waste washing water. First, in the three-step evaporation-crystallization process, pure sodium chloride and solid mixture of sodium and potassium chlorides were obtained separately, and the remaining solution contained potassium and calcium chlorides (solution A). And then, the solid mixture was fully dissolved into water (solution B obtained). Finally, ethanol was added into solutions A and B to change the solubility of sodium, potassium, and calcium chlorides within the mixed solvent of water and ethanol. During the ethanol-adding precipitation process, each salt was separated individually, and the purity of the raw production in laboratory experiments reached about 90%. The ethanol can be recycled by distillation and reused as the solvent. Therefore, this technology may bring both environmental and economic benefits.

  4. Characterization and modes of occurrence of elements in feed coal and fly ash; an integrated approach

    USGS Publications Warehouse

    Brownfield, M.E.

    2002-01-01

    Despite certain environmental concerns, coal is likely to remain an important component of the United States energy supply, partly because it is the most abundant domestically available fossil fuel. One of the concerns about coal combustion for electricity production is the potential release of elements from coal and coal combustion products (CCPs) - fly ash - to the environment. This concern prompted the need for accurate, reliable, and comprehensive information on the contents and modes of occurrence of selected elements in power-plant feed coal and fly ash. The U.S. Geological Survey (USGS) is collaborating with several electric utilities to determine the chemical and mineralogical properties of feed coal and fly ash. Our first study analyzed coal and fly ash from a Kentucky power plant, which uses many different bituminous coals from the Appalachian and Illinois Basins. Sulfur content of these feed coals rangedfrom 2.5 to 3.5 percent. The second study analyzed coal and fly ash from an Indiana power plant, which uses subbituminous coal from the Powder River Basin (fig. 1). Sulfur content of this feed coal ranged from 0.23 to 0.47 percent. A summary of important aspects of our approach and results are presented in this report. 

  5. Thermo-mechanical properties and microfabric of fly ash-stabilized gold tailings.

    PubMed

    Lee, Joon Kyu; Shang, Julie Q; Jeong, Sangseom

    2014-07-15

    This paper studies the changes in thermal conductivity, temperature, and unconfined compressive strength of gold tailings and fly ash mixtures during the curing period of 5 days. The microfabric of the cured mixtures was investigated with mercury intrusion porosimetry (MIP). The mixture samples were prepared at their maximum dry unit weight and optimum moisture content. Effect of adding fly ash to gold tailings (i.e., 0, 20, and 40% of the dry weight of tailings) was examined, and a comparison was made on samples prepared at the same fly ash content by replacing gold tailings with humic acid (i.e., gold tailings and humic acid ratios of 100:0, 90:10, and 80:20 by weight) or by varying pore fluid chemistry (i.e., water and salt solutions of 1M NaCl and CaCl2). The results show that the initial thermal conductivity of the samples is sensitive to the mixture proportion and a declination in the thermal conductivity is observed due to hydration of fly ash and evaporation. Inclusion of fly ash and salts into gold tailings improves the unconfined compressive strength but the presence of humic acid in samples leads to the decrease of the strength. MIP results reveal the pore structure changes associated with the packing states of the samples that reflect the influential factors considered. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Effect of fly ash inhalation on biochemical and histomorphological changes in rat liver.

    PubMed

    Mani, U; Prasad, A K; Suresh Kumar, V; Lal, Kewal; Kanojia, R K; Chaudhari, B P; Murthy, R C

    2007-09-01

    The effect of fly ash inhalation (4h daily, 5 days a week) for 28 days on the deposition of metal ions and histopathological changes in the liver and serum clinical enzymes has been studied. The results showed an increase in the concentration of metals such as cadmium (Cd), chromium (Cr), copper (Cu), manganese (Mn), and lead (Pb) in the tissues of exposed rats. The level of metals varied from metal to metal and from organ to organ. Level of serum enzymes such as serum glutamate oxaloacetate transaminase, serum glutamate pyruvate transaminase, and alkaline phosphatase were increased in fly ash exposed rats using whole body inhalation exposure as compared to sham controls. Histopathological studies of rat liver exposed to fly ash revealed infiltration of mononuclear cells in and around the portal triads, which seems to be laden with fly ash particles. Hepatocytes showed necrotic changes such as pyknotic nuclei, karyorrhexis, and karyolytic. These changes were more towards the centrolobular areas than the midzonal and periportal areas. These findings demonstrate that the toxic metals of inhaled fly ash in rats may get translocated into extrapulmonary organs, become deposited and hence may manifest their toxic effects on different tissues.

  7. Effects of instillation of fly ash in the lung: physiochemical properties and immune responses

    SciTech Connect

    Fujimaki, H.; Kawagoe, A.; Ozawa, M.; Yonemoto, J.; Watanabe, N. )

    1989-08-01

    In this study, we examined physiochemical properties of fly ash and aluminum silicate and investigated the effects of these compounds on IgE antibody production and macrophage response in the lung. Fly ash was round in shape, and aluminum silicate was indefinite in shape with respirable size. Both compounds consisted of alumina and silica as the main elements with respirable size. Enhanced IgE and IgG antiovalbumin (OA) antibody production was observed in mice first instilled intratracheally with the aluminum compounds and then given OA aerosol exposure. Histopathologic observations after instillation of fly ash and aluminum silicate showed that a large number of macrophages had ingested the compounds. However, the amount of free compound and the distribution of macrophages were different in mice given fly ash from those given aluminum silicate. These data indicate that particles of fly ash and aluminum silicate instilled into lung act as adjuvant for the production of IgE and IgG antibodies.

  8. Role of fly ash in the removal of organic pollutants from wastewater

    SciTech Connect

    M. Ahmaruzzaman

    2009-03-15

    Fly ash, a relatively abundant and inexpensive material, is currently being investigated as an adsorbent for the removal of various organic pollutants from wastewater. The wastewater contains various types of phenolic compounds, such as chloro, nitro, amino, and other substituted compounds. Various types of pesticides, such as lindane, malathion, carbofuran, etc., and dyes, such as, methylene blue, crystal violet, malachite green, etc., are also present in the wastewater. These contaminants pollute the water stream. These organic pollutants, such as phenolic compounds, pesticides, and dyes, etc., can be removed very effectively using fly ash as adsorbent. This article presents a detailed review on the role of fly ash in the removal of organic pollutants from wastewater. Adsorption of various pollutants using fly ash has been reviewed. The adsorption mechanism and other influencing factors, favorable conditions, and competitive ions, etc., on the adsorption process have also been discussed in this paper. It is evident from the review that fly ash has demonstrated good removal capabilities for various organic compounds. 171 refs., 3 figs., 5 tabs.

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

    SciTech Connect

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

    2012-01-18

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

  10. Reductive transformation of p-nitrotoluene by a new iron-fly ash packing.

    PubMed

    Yu, Baizhen; Jin, Ruofei; Liu, Guangfei; Zhou, Jiti

    2015-11-01

    A new iron-fly ash packing was studied for reductive transformation of p-nitrotoluene. The packing was made of iron, fly ash and kaolin with the mass ratio of 36:7:2. A reactor was designed to investigate the long-term performance of the packing. The results showed that the reduction of p-nitrotoluene increased with decreasing pH, because the reduction potential of reaction increased with the concentration of H(+). The pH was one of the key factors impacting the reductive transformation of p-nitrotoluene. Comparing iron-activated carbon packing with the new iron-fly ash packing, the reduction efficiencies were respectively 76.61% and 75.36% after 20days. The reduction efficiency for both was around 50% at 40days. It was evident that these two kinds of packing had no significant difference in their capability for p-nitrotoluene reductive transformation. Compared with iron-activated carbon, the new iron-fly ash packing had obvious advantages in terms of manufacturing costs and environmental pollution degradation. This study showed that the new iron-fly ash packing had good performance in reductive transformation of nitrotoluene compounds. Copyright © 2015. Published by Elsevier B.V.

  11. [Influence of laser energy on measurement of unburned carbon in fly Ash particle flow].

    PubMed

    Bai, Kai-Jie; Tian, Hao-Chen; Yao, Shun-Chun; Zhang, Bo; Shen, Yue-Liang; Xu, Qi-Sheng; Lu, Ji-Dong

    2014-05-01

    The fly ash particle flow was produced by a screw feeder and then ablated by a pulse laser to create plasma. The emission spectra of fly ash were detected by laser-induced breakdown spectroscopy. Th