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Sample records for plant fly ash

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Influence of mercury from fly ash on cattle reared nearby thermal power plant.

    PubMed

    Mahajan, Vikas Eknath; Yadav, Raju Ravindra; Dakshinkar, Narayan Purushottam; Dhoot, Vinod Madanlal; Bhojane, Gautam Ramkrishna; Naik, Madhura Kiran; Shrivastava, Preeti; Naoghare, Pravin Krishnarao; Krishnamurthi, Kannan

    2012-12-01

    Cattle grazing nearby coal-fired power stations are exposed to fly ash. The present investigation aims to assess the environmental and health impacts of fly ash containing mercury emitted from thermal power plant. The health effect of fly ash were studied using 20 lactating cattle reared within a 5-km radius of s thermal power plant for the possible effect of fly ash such as the alterations in hematological and biochemical parameters of blood, milk, and urine. Results indicated that the hemoglobin levels (6.65 ± 0.40 g/dl) were significantly reduced in all the exposed animals. Biochemical parameters viz., blood urea nitrogen (27.35 ± 1.19 mg/dl), serum glutamate oxaloacetate transaminase (43.39 ± 3.08 IU/l), albumin, and creatinine were found to be increased, whereas serum glutamate pyruvic transaminase (29.26 ± 2.02) and Ca(2+) were observed to be statistically insignificant in exposed animals. Mercury concentrations estimated in the blood, milk, and urine of exposed (n = 20) and control (n = 20) animals were 7.41 ± 0.86, 4.75 ± 0.57, 2.08 ± 0.18, and 1.05 ± 0.07, 0.54 ± 0.03, 0.20 ± 0.02 μg/kg, respectively. The significant increase (P < 0.01) in the levels of mercury in blood, milk, and urine of exposed animals in comparison to control indicated that the alterations of biochemical parameters in exposed cattle could be due to their long term exposure to fly ash mercury which may have direct or indirect impact on human populations via food chain.

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

    PubMed

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

    2010-08-01

    The control of mercury in the air emissions from coal-fired power plants is an on-going challenge. The native unburned carbons in fly ash can capture varying amounts of Hg depending upon the temperature and composition of the flue gas at the air pollution control device, with Hg capture increasing with a decrease in temperature; the amount of carbon in the fly ash, with Hg capture increasing with an increase in carbon; and the form of the carbon and the consequent surface area of the carbon, with Hg capture increasing with an increase in surface area. The latter is influenced by the rank of the feed coal, with carbons derived from the combustion of low-rank coals having a greater surface area than carbons from bituminous- and anthracite-rank coals. The chemistry of the feed coal and the resulting composition of the flue gas enhances Hg capture by fly ash carbons. This is particularly evident in the correlation of feed coal Cl content to Hg oxidation to HgCl2, enhancing Hg capture. Acid gases, including HCl and H2SO4 and the combination of HCl and NO2, in the flue gas can enhance the oxidation of Hg. In this presentation, we discuss the transport of Hg through the boiler and pollution control systems, the mechanisms of Hg oxidation, and the parameters controlling Hg capture by coal-derived fly ash carbons.

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

    PubMed Central

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

    2013-01-01

    The control of mercury in the air emissions from coal-fired power plants is an on-going challenge. The native unburned carbons in fly ash can capture varying amounts of Hg depending upon the temperature and composition of the flue gas at the air pollution control device, with Hg capture increasing with a decrease in temperature; the amount of carbon in the fly ash, with Hg capture increasing with an increase in carbon; and the form of the carbon and the consequent surface area of the carbon, with Hg capture increasing with an increase in surface area. The latter is influenced by the rank of the feed coal, with carbons derived from the combustion of low-rank coals having a greater surface area than carbons from bituminous- and anthracite-rank coals. The chemistry of the feed coal and the resulting composition of the flue gas enhances Hg capture by fly ash carbons. This is particularly evident in the correlation of feed coal Cl content to Hg oxidation to HgCl2, enhancing Hg capture. Acid gases, including HCl and H2SO4 and the combination of HCl and NO2, in the flue gas can enhance the oxidation of Hg. In this presentation, we discuss the transport of Hg through the boiler and pollution control systems, the mechanisms of Hg oxidation, and the parameters controlling Hg capture by coal-derived fly ash carbons. PMID:24223466

  1. Comparative study on elemental composition and DNA damage in leaves of a weedy plant species, Cassia occidentalis, growing wild on weathered fly ash and soil.

    PubMed

    Love, Amit; Tandon, Rajesh; Banerjee, B D; Babu, C R

    2009-10-01

    Open dumping of fly ash in fly ash basins has significant adverse environmental impacts due to its elevated trace element content. In situ biomonitoring of genotoxicity is of practical value in realistic hazard identification of fly ash. Genotoxicity of openly disposed fly ash to natural plant populations inhabiting fly ash basins has not been investigated. DNA damage, and concentrations of As, Co, Cr, Cu and Ni in the leaves of natural populations of Cassia occidentalis growing at two contrasting sites-one having weathered fly ash (fly ash basin) and the other having soil (reference site) as plant growth substrates-were assessed. The foliar concentrations of As, Ni and Cr were two to eight fold higher in plants growing on fly ash as compared to the plants growing on soil, whereas foliar concentrations of Cu and Co were similar. We report, for the first time, based upon comet assay results, higher levels of DNA damage in leaf tissues of Cassia occidentalis growing wild on fly ash basin compared to C. occidentalis growing on soil. Correlation analysis between foliar DNA damage and foliar concentrations of trace elements suggests that DNA damage may perhaps be associated with foliar concentrations of As and Ni. Our observations suggest that (1) fly ash triggers genotoxic responses in plants growing naturally on fly ash basins; and (2) plant comet assay is useful for in situ biomonitoring of genotoxicity of fly ash.

  2. Mercury in coals and fly ashes from Republika and Bobov dol thermoelectric power plants

    USGS Publications Warehouse

    Kostova, I.; Vassileva, C.; Hower, J.; Mastalerz, Maria; Vassilev, S.; Nikolova, N.

    2011-01-01

    Feed coal and y ash samples were collected at Republika and Bobov Dol thermoelectric power plants (TPPs). The y ashes (FAs) were collected fromthree rows of the hot-side electrostatic precipitators (ESPs) array. Each sam- ple was wet-screened at 100, 200, 325 and 500 mesh. The coals and y ashes were characterized with regard to their petrological and chemical composition (including mercury content) and to their surface area properties. The calculated enrichment factor (EF) shows that the Hg concentrations in the bulk coal samples from Republika and Bobov Dol TPPs are 2.19 and 1.41, respectively. In some coal size fractions the EF can be up to 4 times higher than the Clarke value. The calculated EF for fly ashes shows that the Hg concentrations in the bulk samples studied are lower (between 0.03 and 0.32) than the Clarke value. The most enriched in Hg are the fly ashes from the 3rd ESP row of Republika TPP. The Hg distribution in bulk FAs taken from dierent rows of the electrostatic precipitators of both TPPs studied shows well established tendency of gradual increase in the Hg content from the 1st to the 2nd and 3rd ESP rows. The correlation between Hg content and surface area, mesopore and micropore volume of y ashes was also done in the present investigation.

  3. Development of Fly Ash Derived Sorbents to Capture CO2 from Flue Gas of Power Plants

    SciTech Connect

    M. Mercedes Maroto-Valer; John M. Andresen; Yinzhi Zhang; Zhe Lu

    2003-12-31

    This research program focused on the development of fly ash derived sorbents to capture CO{sub 2} from power plant flue gas emissions. The fly ash derived sorbents developed represent an affordable alternative to existing methods using specialized activated carbons and molecular sieves, that tend to be very expensive and hinder the viability of the CO{sub 2} sorption process due to economic constraints. Under Task 1 'Procurement and characterization of a suite of fly ashes', 10 fly ash samples, named FAS-1 to -10, were collected from different combustors with different feedstocks, including bituminous coal, PRB coal and biomass. These samples presented a wide range of LOI value from 0.66-84.0%, and different burn-off profiles. The samples also spanned a wide range of total specific surface area and pore volume. These variations reflect the difference in the feedstock, types of combustors, collection hopper, and the beneficiation technologies the different fly ashes underwent. Under Task 2 'Preparation of fly ash derived sorbents', the fly ash samples were activated by steam. Nitrogen adsorption isotherms were used to characterize the resultant activated samples. The cost-saving one-step activation process applied was successfully used to increase the surface area and pore volume of all the fly ash samples. The activated samples present very different surface areas and pore volumes due to the range in physical and chemical properties of their precursors. Furthermore, one activated fly ash sample, FAS-4, was loaded with amine-containing chemicals (MEA, DEA, AMP, and MDEA). The impregnation significantly decreased the surface area and pore volume of the parent activated fly ash sample. Under Task 3 'Capture of CO{sub 2} by fly ash derived sorbents', sample FAS-10 and its deashed counterpart before and after impregnation of chemical PEI were used for the CO{sub 2} adsorption at different temperatures. The sample FAS-10 exhibited a CO{sub 2} adsorption capacity of 17

  4. Combustion of sponge iron plant wastes -- Char and fly ash in FBC boilers

    SciTech Connect

    Rajavel, M.; Muthukrishnan, M.; Banerjee, M.; Natarajan, R.

    1997-12-31

    Coal based sponge iron plants generate large quantity of waste materials in the form of kiln char and fly ash. This material has a very little fuel value owing to the fact that it contains a large percentage of ash and it is almost free from volatiles. Added to this, wide size range of the kiln rejects makes it practically impossible to burn in conventional firing. However, it is realized that the overall economy of the sponge iron plant is likely to be greatly enhanced if the char, the fly ash and a considerable quantity of coal fines, separated in the coal preparation plant, can be utilized. The only possible way to gainfully use these fuels is by fluidized bed combustion. Extensive tests were conducted with these fuels in bubbling fluidized bed combustion test facilities at BHEL, Tiruchirapalli, India. The presentation highlights the experience gained with the above waste fuels in BHEL test facilities and discusses the findings which were subsequently used to design large size FBC boilers.

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

    SciTech Connect

    Hicks, J.; Yager, J.

    2006-08-15

    This study presents measurements of airborne concentrations of respirable crystalline silica in the breathing zone of workers who were anticipated to encounter coal fly ash. Six plants were studied; two were fired with lignite coal, and the remaining four plants used bituminous and subbituminous coals. A total of 108 personal breathing zone respirable dust air samples were collected. Bulk samples were also collected from each plant site and subjected to crystalline silica analysis. Airborne dust particle size analysis was measured where fly ash was routinely encountered. The results from bituminous and subbituminous fired plants revealed that the highest airborne fly ash concentrations are encountered during maintenance activities: 0.008 mg/m{sup 3} to 96 mg/m{sup 3} (mean of 1.8 mg/m{sup 3}). This group exceeded the threshold limit values (TLV) in 60% of the air samples. During normal production activities, airborne concentrations of crystalline silica ranged from nondetectable to 0.18 mg/m{sup 3} (mean value of 0.048 mg/m{sup 3}). Air samples collected during these activities exceeded the current and proposed TLVs in approximately 54% and 65% of samples, respectively. Limited amounts of crystalline silica were detected in samples collected from lignite-fired plants, and approximately 20% of these air samples exceeded the current TLV. Particle size analysis in areas where breathing zone air samples were collected revealed mass median diameters typically between 3 {mu}m and 8 {mu}m. Bulk and air samples were analyzed for all of the common crystalline silica polymorphs, and only alpha quartz was detected.

  6. Characterization of the fly ashes from the lignite burning power plants of northern Greece based on their quantitative mineralogical composition.

    PubMed

    Kostakis, G

    2009-07-30

    In the present work, mineralogical analysis of fly ashes produced from the brown coal burning power plants of Agios Dimitrios, Kardia, Ptolemais, LIPTOL, Amynteon, and Achlada-Meliti (Western Macedonia, Greece) was performed, with the aim of characterizing the ashes on the basis of their quantitative mineral phase composition and asses their variability at different time periods. The fly ashes from the Agios Dimitrios, Kardia, and Ptolemais power plants were found to have nearly the same mineralogical composition, consisting mainly of feldspars, lime, anhydrite, quartz, calcium silicates, and high amounts of amorphous phases. The fly ashes from Amynteon were slightly different, having lower content of lime and higher content of feldspars, whilst those from LIPTOL had a relative variable quantitative composition. The fly ashes from the Meliti-Achlada power plant consisted mainly of amorphous phases (very high amounts), mullite, feldspars, and quartz. The mineralogical composition of the ashes produced in all the power plants, except from these of LIPTOL, did not fluctuate significantly over time. An assessment of the hydraulic (cementitious) or pozzolanic character of the ashes is proposed, introducing the use of triangle diagrams A-B-C, which represent the total fraction of the phases with hydraulic or pozzolanic (A), inert (B) character, and the amorphous phases (C).

  7. 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.

  8. Sulfur-bearing coatings on fly ash from a coal-fired power plant: Composition, origin, and influence on ash alteration

    USGS Publications Warehouse

    Fishman, N.S.; Rice, C.A.; Breit, G.N.; Johnson, R.D.

    1999-01-01

    Fly ash samples collected from two locations in the exhaust stream of a coal-fired power plant differ markedly with respect to the abundance of thin (???0.1 ??m) sulfur-rich surface coatings that are observable by scanning electron microscopy. The coatings, tentatively identified as an aluminum-potassium-sulfate phase, probably form upon reaction between condensed sulfuric acid aerosols and glass surfaces, and are preferentially concentrated on ash exposed to exhaust stream gases for longer. The coatings are highly soluble and if sufficiently abundant, can impart an acidic pH to solutions initially in contact with ash. These observations suggest that proposals for ash use and predictions of ash behavior during disposal should consider the transient, acid-generating potential of some ash fractions and the possible effects on initial ash leachability and alteration. ?? 1998 Elsevier Science Ltd.

  9. From in-situ coal to fly ash: A study of coal mines and power plants from Indiana

    USGS Publications Warehouse

    Mastalerz, Maria; Hower, J.C.; Drobniak, A.; Mardon, S.M.; Lis, G.

    2004-01-01

    This paper presents data on the properties of coal and fly ash from two coal mines and two power plants that burn single-source coal from two mines in Indiana. One mine is in the low-sulfur (5%) Springfield Coal Member of the Petersburg Formation (Pennsylvanian). Both seams have comparable ash contents (???11%). Coals sampled at the mines (both raw and washed fractions) were analyzed for proximate/ultimate/sulfur forms/heating value, major oxides, trace elements and petrographic composition. The properties of fly ash from these coals reflect the properties of the feed coal, as well as local combustion and post-combustion conditions. Sulfur and spinel content, and As, Pb and Zn concentrations of the fly ash are the parameters that most closely reflect the properties of the source coal. ?? 2004 Elsevier B.V. All rights reserved.

  10. 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.

  11. Changes of the soil environment affected by fly ash dumping site of the electric power plant

    NASA Astrophysics Data System (ADS)

    Weber, Jerzy; Gwizdz, Marta; Jamroz, Elzbieta; Debicka, Magdalena; Kocowicz, Andrzej

    2014-05-01

    In this study the effect of fly ash dumping site of the electric power plant on the surrounding soil environment was investigated. The fly ash dumping site collect wastes form brown coal combustion of Belchatow electric power station, central Poland. The dumping site is surrounding by forest, where pine trees overgrow Podzols derived from loose quartz sands. The soil profiles under study were located at a distance of 50, 100, 400 and 500 m from the dumping site, while control profiles were located 8 km away from the landfill. In all horizons of soil profiles the mpain hysico-chemical and chemical properties were determined. The humic substances were extracted from ectohumus horizons by Shnitzer's method, purified using XAD resin and freeze-dried. The fulvic acids were passed through a cation exchange column and freeze-dried. Optical density, elemental composition and atomic ratios were determined in the humic and fulvic acids. Organic carbon by KMnO4 oxidation was also determined in the organic soil horizons. The fly ash from the landfill characterized by high salinity and strong alkaline reaction (pH=10), which contributed significantly to the changes of the pH values in soils horizons. The alkalization of soils adjacent to the landfill was found, which manifested in increasing of pH values in the upper soil horizons. The impact of the landfill was also noted in the changes of the soil morphology of Podzols analysed. As a result of the alkalization, Bhs horizons have been converted into a Bs horizons. Leaching of low molecular humus fraction - typical for podzolization - has been minimized as a result of pH changes caused by the impact of the landfill, and originally occurring humic substances in the Bhs horizon (present in the control profiles) have been probably transported out of the soil profile and then into the groundwater.

  12. 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.

  13. 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.

  14. Radioactivity of size fractionated fly-ash emissions from a peat- and oil-fired power plant.

    PubMed

    Mustonen, R; Jantunen, M

    1985-12-01

    Concentrations of gamma-emitting natural radionuclides and 137Cs were analyzed in the size fractionated fly-ash emissions from a 100-MWt peat- and oil-fired power plant. The emitted fly ash was separated into five size fractions with a high-volume impactor with cut sizes of 1.3 micron, 2.1 micron, 4.2 micron and 10 micron. The greatest activity emissions were associated with the smallest size fraction, below 1.3 micron. The mass median aerodynamic diameter (MMAD) of the fly-ash particles after the electrostatic precipitator was 1.9 micron with a geometric standard deviation of 3.0 and the median of the 32 fly-ash emission samples was 8.73 mg MJ-1 with a geometric standard deviation of 1.3. Lead-210 gave the greatest particulate activity emission per input fuel energy, 18.7 mBq MJ-1, and showed a strong enrichment onto small fly-ash particles.

  15. Physical and chemical characterization of fly ashes from Swiss waste incineration plants and determination of the ash fraction in the nanometer range.

    PubMed

    Buha, Jelena; Mueller, Nicole; Nowack, Bernd; Ulrich, Andrea; Losert, Sabrina; Wang, Jing

    2014-05-06

    Waste incineration had been identified as an important source of ultrafine air pollutants resulting in elaborated treatment systems for exhaust air. Nowadays, these systems are able to remove almost all ultrafine particles. However, the fate of ultrafine particles caught in the filters has received little attention so far. Based on the use of engineered nano-objects (ENO) and their transfer into the waste stream, it can be expected that not only combustion generated nanoparticles are found in fly ashes but that many ENO finally end up in this matrix. A more detailed characterization of the nanoparticulate fraction of fly ashes is therefore needed. Physical and chemical characterizations were performed for fly ashes from five selected waste incineration plants (WIPs) with different input materials such as municipal waste, wood and sewage sludge. The intrinsic densities of the fly ashes were in the range of 2.7-3.2 g/cm(3). When the fly ash particle became airborne, the effective density depended on the particle size, increasing from 0.7-0.8 g/cm(3) for 100-150 nm to 2 g/cm(3) for 350-500 nm. The fly ash samples were fractionated at 2 μm, yielding fine fractions (<2 μm) and coarse fractions (>2 μm). The size distributions of the fine fractions in the airborne form were further characterized, which allowed calculation of the percentage of the fly ash particles below 100 nm. We found the highest mass-based percentage was about 0.07%; the number percentage in the fine fraction was in the range of 4.8% to 22%. Comparison with modeling results showed that ENO may constitute a considerable part of the fly ash particles below 100 nm. Chemical analyses showed that for the municipal waste samples Ca and Al were present in higher concentrations in the coarse fraction; for the mixed wood and sludge sample the P concentration was higher in the coarse fraction; for most other samples and elements they were enriched in the fine fraction. Electron microscopic images of fly ashes

  16. Polychlorinated biphenyls in fly ashes collected from five coal-fired power plants in North China

    NASA Astrophysics Data System (ADS)

    Li, Zhiyong; Li, Xu; Ma, Huiqiao; Fan, Lin

    2017-01-01

    The 5 coal fly ash samples (CFA) were systematically collected from 5 coal-fired power plants (CFPPs) in North China for analysis of 86 PCB congeners. The predominant PCB congeners were PCB-6, -4/10, -28, -18, -19 and -16/32, which belonged to lighter molecular weight (LMW) congeners. The Σ86PCBs for 5 CFPPs ranged from 10.93 to 32.06 ng/g with the mean value as 16.01 ng/g. The PCBs in CFA were dominated by LMW-PCBs with 2-, 3- and 4-Cl PCBs contributed 34.80%, 39.18% and 9.21% to the Σ86PCBs. The TEQ concentrations for 5 CFPPs was 42.54 pg/g higher than 4 pg/g designed by Canada for soil quality, indicated the using of CFA as soil amendment should be cautioned.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Effect of fly ash application on soil microbial response and heavy metal accumulation in soil and rice plant.

    PubMed

    Nayak, A K; Raja, R; Rao, K S; Shukla, A K; Mohanty, Sangita; Shahid, Mohammad; Tripathi, R; Panda, B B; Bhattacharyya, P; Kumar, Anjani; Lal, B; Sethi, S K; Puri, C; Nayak, D; Swain, C K

    2015-04-01

    Fly ash (FA), a byproduct of coal combustion in thermal power plants, has been considered as a problematic solid waste and its safe disposal is a cause of concern. Several studies proposed that FA can be used as a soil additive; however its effect on microbial response, soil enzymatic activities and heavy metal accumulation in soil and grain of rice (cv. Naveen) to fly ash (FA) application was studied in a pot experiment during dry season 2011 in an Inceptisol. Fly ash was applied at a rate of zero per cent (FS), five per cent (FA5), ten per cent (FA10), twenty per cent (FA20), 40 per cent (FA40) and 100 per cent (FA100) on soil volume basis with nitrogen (N), phosphorus (P) and potassium (K) (40:20:20mg N:P:Kkg(-1) soil) with six replications. Heavy metals contents in soil and plant parts were analysed after harvest of crop. On the other hand, microbial population and soil enzymatic activities were analysed at panicle initiation stage (PI, 65 days after transplanting) of rice. There was no significant change in the concentration of zinc (Zn), iron (Fe), copper (Cu), manganese (Mn), cadmium (Cd) and chromium (Cr) with application of fly ash up to FA10. However, at FA100 there was significant increase of all metals concentration in soil than other treatments. Microorganisms differed in their response to the rate of FA application. Population of both fungi and actinomycetes decreased with the application of fly ash, while aerobic heterotrophic bacterial population did not change significantly up to FA40. On the other hand, total microbial activity measured in terms of Fluorescein diacetate (FDA) assay, and denitrifiers showed an increased trend up to FA40. However, activities of both alkaline and acid phosphatase were decreased with the application of FA. Application of FA at lower levels (ten to twenty per cent on soil volume basis) in soil enhanced micronutrients content, microbial activities and crop yield.

  3. Acoustic agglomeration of power plant fly ash: Quarterly technical report, November 5, 1986--February 5, 1987

    SciTech Connect

    Reethof, G.

    1987-03-20

    The objective of this project is to complete the investigations on the use of high intensity acoustic energy to agglomerate micron and submicron sized particulates in fly ash aerosols in order to provide the necessary scientific knowledge and design criteria for the specification of technically and economically viable intermediate flue gas treatment of coal fired power plants. The results of the project are to provide technical and economic information for the better development and evaluation of potential fine particulate control systems. The goals of the proposed work are to further the understanding of certain fundamental processes by means of theoretical and experimental investigations, to include this knowledge in an advanced computerized model of the agglomeration processes. Tests with the two acoustic agglomerators available in Penn State's new High Intensity Acoustics Laboratory will be used to verify the results from the agglomeration simulation. Research work will continue on high power, high efficiency sirens with special emphasis on the nonlinear acoustic phenomena and novel means of significantly increasing siren efficiency. A study will be carried out to evaluate the economics of conventional coal fired power plant clean-up systems using acoustic agglomerators as intermediate flue gas treatment.

  4. Acoustic agglomeration of power plant fly ash for environmental and hot gas cleanup

    SciTech Connect

    Reethof, G.; Koopmann, G.H.

    1989-12-01

    This two year research program has the objectives of completing the several investigations associated with the use of high intensity acoustic energy to agglomerate micron and submicron sized particles in fly ash aerosols in order to provide the necessary scientific knowledge and design criteria for the specification of technically and economically viable intermediate flue gas treatment of coal fired power plants. Goals are to further the understanding of certain fundamental processes by means of theoretical and experimental investigations to include this knowledge in an advanced computerized model of the agglomeration processes. Tests with the acoustic agglomeration facilities available in Penn State's new High Intensity Acoustic Laboratory were to be used to verify the results from the acoustic agglomeration simulations. Research work continued on high power, high efficiency sirens with special emphasis on the nonlinear acoustic phenomena and novel means of significantly increasing siren efficiency. A study was carried out to evaluate the economics of conventional coal fired power plant clean-up systems using acoustic agglomeration as an intermediate flue gas treatment. 154 refs., 152 figs., 30 tabs.

  5. Elemental analysis of trace elements in fly ash sample of Yatağan thermal power plants using EDXRF

    NASA Astrophysics Data System (ADS)

    Dogan, O.; Kobya, M.

    2006-09-01

    Fly ash samples collected by means of an electrostatic precipitator from the lignite-fired Yatağan Power Plants of the located in Turkey was analysed using X-ray fluorescence technique. Five trace elements, namely Nd, Ba, Sr, Mo and As were quantified using XRF. These concentration values can be helpful in developing a environmental pollution abatement approach for various applications of fly ash such as cement manufacture, wastewater treatment, lightweight contraction aggregate, ceramic production, and secondary source in recovery of valuable elements. Present results compared with results of the Kemerkoy thermal power plants [Şahin Y, Karabulut A, Budak G. A practical method for the analysis of overlepped peaks in energy dispersive X-ray spectra. Appl Spectrosc Rev 1996;31:333 45].

  6. 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

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

    PubMed

    Qi, Liqiang; Yuan, Yongtao

    2011-08-15

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

  8. Use of zeolitised coal fly ash for landfill leachate treatment: a pilot plant study.

    PubMed

    Luna, Y; Otal, E; Vilches, L F; Vale, J; Querol, X; Fernández Pereira, C

    2007-01-01

    Treatment of municipal solid waste (MSW) landfill leachate generally results in low percentages of nutrient removal due to the high concentration and accumulation of refractory compounds. For this reason, individual physical, chemical and biological processes have been used for the treatment of raw landfill leachate and sometimes for the mixture of domestic wastewater and landfill leachate. In this work, the possibility of treating landfill leachate was tested in a bench-scale pilot plant by a two-step method combining adsorption and coagulation-flocculation. Zeolite synthesized from coal fly ash, a by-product of coal-fired power stations, was used in this study both as a decantation aid reagent and as an adsorbent of COD and NH4-N. The coagulation-flocculation step was performed by the use of aluminium sulphate and a polyelectrolyte (ACTIPOL A-401). The leachate was collected directly from a storage unit of the organic fraction of MSW, before it was composted. For this reason the raw leachate was diluted before treatment. The sludge was recirculated to enhance the removal efficiency of nutrients as well as to optimize flocculant saving and to decrease sludge production. The results showed that it is possible to remove 43%, 53% and 82% of COD, NH4-N, and suspended solids, respectively. Therefore, this method may be an alternative for ammonium removal, as well as a suitable pre- or post-treatment step, in combination with other processes in order to meet regulatory limits.

  9. Acoustic agglomeration of power-plant fly ash. A comprehensive semi-annual progress report

    SciTech Connect

    Reethof, G.

    1980-02-01

    Results obtained during the reporting period are presented. The agglomeration of submicron fly ash particles has been studied as a function of sound pressure level, sound frequency, loading, and exposure time. A second generation model of the agglomeration process is being developed. A high-frequency, high-intensity variable speed siren delivering at least 600 W at frequencies up to 4000 Hz has been developed and tested. Details on the design and operation are presented. The agglomeration chamber has been completely cleaned and the aerosol generating system has been rebuilt. A mathematical model of the acoustics of agglomeration is being developed. Preliminary results of computerized electron microscopic scanning of fly ash particles during agglomeration are presented. (DMC)

  10. 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.

  11. Removal characteristics of PCDD/Fs by the dual bag filter system of a fly ash treatment plant.

    PubMed

    Lin, Wen-Yinn; Wang, Lin-Chi; Wang, Ya-Fen; Li, Hsing-Wang; Chang-Chien, Guo-Ping

    2008-05-30

    In this study, a dual bag filter system was established to decrease the concentration of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) in the stack flue gases of a fly ash treatment plant, which retained zinc from the fly ash of electric arc furnaces. Compared to the original single bag filter system with activated carbon injection (ACI) of 40 kg h(-1), the PCDD/F concentrations in the stack flue gas after the plant was equipped with the dual bag filter system dropped enormously from 3.38-7.73 ng I-TEQNm(-3) to 0.03 ng I-TEQNm(-3), and the total PCDD/F I-TEQ removal efficiency increased from 97.6% to 99.3% with ACI of 16 kg h(-1), that is, about 40% of the original AC usage. The AC utilization efficiency (0.560 mg I-TEQ absorbed kg ACI(-1)) of the dual bag filter system (AC: 16 kg h(-1)) was estimated about three times higher than that (0.192 mg I-TEQ absorbed kg ACI(-1)) of single bag filter system with ACI (40 kg h(-1)). The reason is that the particulate phase PCDD/Fs and some gas phase PCDD/Fs (captured by the recycled AC/ash mixture) were removed first by the first bag filter, and the rest of the gas phase PCDD/Fs were able to be adsorbed more completely by the AC/ash mixture due to a lower fly ash load, and then were removed by the second bag filter.

  12. 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.

  13. 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.

  14. Metal phytoremediation potential of naturally growing plants on fly ash dumpsite of Patratu thermal power station, Jharkhand, India.

    PubMed

    Pandey, Shikha Kumari; Bhattacharya, Tanushree; Chakraborty, Sukalyan

    2016-01-01

    Three naturally growing plants Ipomoea carnea, Lantana camara, and Solanum surattense were found in fly ash dumpsite of Patratu thermal power station, Jharkhand, India. They were assessed for their metal uptake potential. The fly ash was slightly alkaline with very less nitrogen and organic carbon but enriched with phosphorus and heavy metals. Lantana camara and Ipomoea carnea showed good translocation from root to shoot for most of the metals except Mn and Pb. The order of metal accumulation in stem of both the plants were Fe(205mg/kg)>Mn(65mg/kg)>Cu(22.35mg/kg)>Pb(6.6mg/kg)>Cr(3.05mg/kg)>Ni(1 mg/kg)>Cd(0.5 mg/kg) and Fe(741 mg/kg)>Mn(154.05 mg/kg)>Cu(20.75 mg/kg)>Pb(6.75 mg/kg)>Ni(4.0 mg/kg)>Cr(3.3mg/kg)>Cd(0.05mg/kg), respectively. But Solanum surattense accumulated most of the metals in roots. The order was in the following order, Mn (382.2mg/kg) >Fe (264.1mg/kg) > Cu (25.35mg/kg) >Pb (5.95 mg/kg) > Ni (1.9 mg/kg) > Cr (1.8mg/kg) > Cd (0.55 mg/kg). The order of Bioconcentration factor (BCF) in root and shoot followed almost the same order as, Mn>Fe>Ni>Pb>Cu>Cr≈ Cd in all the three species. ANOVA showed significant variation in metal accumulation by root and stem between the species. Finally, it can be concluded that Solanum surattense can be used as phytostabilizer and other two species as phytoextractor of metal for fly ash dumpsite reclamation.

  15. Chemical and physical properties of cyclone fly ash from the grate-fired boiler incinerating forest residues at a small municipal district heating plant (6MW).

    PubMed

    Pöykiö, R; Rönkkömäki, H; Nurmesniemi, H; Perämäki, P; Popov, K; Välimäki, I; Tuomi, T

    2009-03-15

    In Finland, the new limit values for maximal allowable heavy metal concentrations for materials used as an earth construction agent came into force in July 2006. These limit values are applied if ash is utilized, e.g. in roads, cycling paths, pavements, car parks, sport fields, etc. In this study we have determined the most important chemical and physical properties of the cyclone fly ash originating from the grate-fired boiler incinerating forest residues (i.e. wood chips, sawdust and bark) at a small municipal district heating plant (6 MW), Northern Finland. This study clearly shows that elements are enriched in cyclone fly ash, since the total element concentrations in the cyclone fly ash were within 0.2-10 times higher than those in the bottom ash. The total concentrations of Cd (25 mg kg(-1); d.w.), Zn (3630 mg kg(-1); d.w.), Ba (4260 mg kg(-1); d.w.) and Hg (1.7 mg kg(-1); d.w.) exceeded the limit values, and therefore the cyclone fly ash cannot be used as an earth construction agent. According to the leached amounts of Cr (38 mg kg(-1); d.w.), Zn (51 mg kg(-1); d.w.) and sulphate (50,000 mg kg(-1); d.w.), the cyclone fly ash is classified as a hazardous waste, and it has to be deposited in a hazardous waste landfill.

  16. 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.

  17. Hg and Se capture and fly ash carbons from combustion of complex pulverized feed blends mainly of anthracitic coal rank in Spanish power plants

    SciTech Connect

    I. Surez-Ruiz; J.C. Hower; G.A. Thomas

    2007-01-15

    In this work, the petrology and chemistry of fly ashes produced in a Spanish power plant from the combustion of complex pulverized feed blends made up of anthracitic/meta-anthracitic coals, petroleum, and natural coke are investigated. It was found that the behavior of fly ash carbons derived from anthracitic coals follows relatively similar patterns to those established for the carbons from the combustion of bituminous coals. Fly ashes were sampled in eight hoppers from two electrostatic precipitator (ESP) rows. The characterization of the raw ashes and their five sieved fractions (from {gt}150 to {lt}25 {mu}m) showed that glassy material, quartz, oxides, and spinels in different proportions are the main inorganic components. As for the organic fraction, the dominant fly ash carbons are anisotropic carbons, mainly unburned carbons derived from anthracitic vitrinite. The concentration of Se and Hg increased in ashes of the second ESP row, this increase being related to the higher proportion of anisotropic unburned carbons, particularly those largely derived from anthracitic vitrinite in the cooler ashes of the ESP (second row) and also related to the decrease in the flue gas temperature. This suggests that the flue gas temperature plays a major role in the concentration of mercury for similar ratios of unburned carbons. It was also found that Hg is highly concentrated in the medium-coarser fractions of the fly ashes ({gt} 45 {mu}m), there being a positive relationship between the amount of these carbons, which are apparently little modified during the combustion process, in the medium-coarse fractions of the ashes and the Hg retention. According to the results obtained, further research on this type of fly ash could be highly productive. 28 refs., 10 figs., 8 tabs.

  18. Prospects for using the fly ash produced at thermal power plants in the Rostov region

    NASA Astrophysics Data System (ADS)

    Fedorova, N. V.; Shaforost, D. A.

    2015-01-01

    A detailed analysis of the chemical composition of the fuel mineral component and admixtures in ash and slag materials is presented taking as an example some of coal-fired thermal power plants in the Rostov region. The physicochemical properties of ash and slag components from different coals that are of interest for industrial use are considered together with methods for separating them. The list of such components includes hollow aluminum silicate microspheres, inert mass of aluminum silicate composition, magnetite microballs, unburned coal particles, carbonate microspheres, heavy fraction containing ferrosilicium, admixtures of noble metals and rare and trace elements. Various ways of using these components directly at thermal power plants and enterprises in the Rostov region are proposed.

  19. 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

  20. Magnetic susceptibility mapping of fly ash in soil samples near a coal-burning power plant in Pointe Coupee Parish, Louisiana.

    NASA Astrophysics Data System (ADS)

    Elhelou, O.; Richter, C.

    2015-12-01

    Atmospheric deposition of pollutants is a major health and environmental concern. In a 2010 study, the CATF attributed over 13,000 deaths each year to fly ash and other fine particles emitted by U.S. coal-burning power plants. The magnetic properties of fly ash allows for mapping an area suspect of PM pollution faster and more efficiently than by conducting chemical analysis as the former alternative. The objective of this study is to detect the presence of magnetic particles related to the migration of fly ash from a nearby coal power plant over parts of Pointe Coupee Parish, LA. This is based on the idea that the fly ash that is released into the atmosphere during the coal burning process contains heavy metals and magnetic particles in the form of ferrospheres, which can be used to trace back to the source. Maps of the top and sub soil were generated to differentiate the magnetic susceptibility values of the heavy metals potentially attributed to the migration and settling of fly ash onto the surface from any pre-existing or naturally occurring heavy metals in the sub soil. A 60 km2 area in Pointe Coupee Parish was investigated in approximately 0.5 km2 subsets. The area in Pointe Coupee Parish, LA was selected because land use is predominantly rural with the Big Cajun II power plant as the main contributor for air borne contaminants. Samples of fly ash obtained directly from the source below one of the power plant's precipitators were also analyzed to verify the field and laboratory analysis. Contour maps representing the spatial distribution of fly ash over Pointe Coupee, LA, along with histograms of magnetic susceptibility values, and chemical analysis all indicate a correlation between the proximity to the power plant and the predominant wind direction. Acquisition curves of the isothermal remnant magnetization demonstrate the presence of predominantly low coercivity minerals (magnetite) with a small amount of a high-coercivity phase. The microstructure of the

  1. Bioaccumulation and translocation of metals in the natural vegetation growing on fly ash lagoons: a field study from Santaldih thermal power plant, West Bengal, India.

    PubMed

    Maiti, Subodh Kumar; Jaiswal, Shishir

    2008-01-01

    A field study was conducted in the fly ash lagoons of Santandih Thermal Power Plant located in West Bengal (India) to find out total, EDTA and DTPA extractable metals in fly ash and their bioaccumulation in root and shoot portion of the naturally growing vegetation. Fly ash sample has alkaline pH and low conductivity. The concentration of total Cu, Zn, Pb and Ni were found higher than weathered fly ash and natural soil, where as Co, Cd and Cr were found traces. Five dominant vegetation namely, Typha latifolia, Fimbristylis dichotoma, Amaranthus defluxes, Saccharum spontaenum and Cynodon dactylon were collected in the winter months (November-December). Bioaccumulation of metals in root and shoot portions were found varied significantly among the species, but all concentration were found within toxic limits. Correlation between total, DTPA and EDTA extractable metals viz. root and shoot metals concentration were studied. Translocation factor (TF) for Cu, Zn and Ni were found less than unity, indicates that these metals are immobilized in the root part of the plants. Metals like Mn have TF greater than unity. The study infers that natural vegetation removed Mn by phytoextraction mechanisms (TF > 1), while other metals like Zn, Cu, Pb and Ni were removed by rhizofiltration mechanisms (TF < 1). The field study revealed that T. latifolia and S. spontaenum plants could be used for bioremediation of fly ash lagoon.

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

    PubMed

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

    2014-01-15

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

  3. Comparative study of the microstructural and magnetic properties of fly ashes obtained from different thermal power plants in West Bengal, India.

    PubMed

    Bhattacharjee, Ashis; Mandal, Haradhan; Roy, Madhusudan; Kusz, Joachim; Hofmeister, Wolfgang

    2013-10-01

    This paper deals with the physical nature of the fly ashes obtained from two thermal power plants, situated in West Bengal, India. The fly ash samples are characterized by using comprehensive techniques with an emphasis on their ultrafine nature. The particle sizes of the samples are estimated using scanning electron microcopy (SEM) and found to lie within 0.18-5.90 μm. For morphology and compositional analysis, we also use SEM coupled with energy dispersive X-ray spectrometry. From X-ray study of the fly ashes the nature of conglomeration is seen to be crystalline, and the major components are mullite (Al6Si2O13) and quartz (SiO2). The magnetic measurement of the fly ash samples was carried out by SQUID magnetometer. (57)Fe Mössbauer spectra are obtained using a conventional constant-acceleration spectrometer with a (57)Co/Rh Mössbauer source. The hyperfine parameters obtained, in general, support the findings as made from XRD analysis and provide a quantitative measure of different iron ions present in the samples. The paper presents experimental data on the physical aspects of the fly ash samples of the thermal power plants which comprise coarse, fine, and ultrafine magnetic particulate materials and attempts to provide an exhaustive analysis.

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

    PubMed

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

    2015-04-09

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

  5. 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.

  6. Identifying glass compositions in fly ash

    NASA Astrophysics Data System (ADS)

    Aughenbaugh, Katherine; Stutzman, Paul; Juenger, Maria

    2016-01-01

    In this study, four Class F fly ashes were studied with a scanning electron microscope; the glassy phases were identified and their compositions quantified using point compositional analysis with k-means clustering and multispectral image analysis. The results showed that while the bulk oxide contents of the fly ashes were different, the four fly ashes had somewhat similar glassy phase compositions. Aluminosilicate glasses (AS), calcium aluminosilicate glasses (CAS), a mixed glass, and, in one case, a high iron glass were identified in the fly ashes. Quartz and iron crystalline phases were identified in each fly ash as well. The compositions of the three main glasses identified, AS, CAS, and mixed glass, were relatively similar in each ash. The amounts of each glass were varied by fly ash, with the highest calcium fly ash containing the most of calcium-containing glass. Some of the glasses were identified as intermixed in individual particles, particularly the calcium-containing glasses. Finally, the smallest particles in the fly ashes, with the most surface area available to react in alkaline solution, such as when mixed with portland cement or in alkali-activated fly ash, were not different in composition than the large particles, with each of the glasses represented. The method used in the study may be applied to a fly ash of interest for use as a cementing material in order to understand its potential for reactivity.

  7. Impact of free calcium oxide content of fly ash on dust and sulfur dioxide emissions in a lignite-fired power plant

    SciTech Connect

    Dimitrios Sotiropoulos; Andreas Georgakopoulos; Nestoras Kolovos

    2005-07-01

    Emitted pollutants from the Agios Dimitrios lignite-fired power plant in northern Greece show a very strong linear correlation with the free calcium oxide content of the lignite ash. Dust (fly ash) emissions are positively correlated to free calcium oxide content, whereas sulfur dioxide (SO{sub 2}) emissions are negatively correlated. As a result, at present, the Agios Dimitrios Power Plant operates very strictly within the legislative limits on atmospheric particulate emission. In the study reported, the factors to be considered in assessing the impact of lignite combustion on the environment are presented and evaluated statistically. The ash appears to have a remarkable SO{sub 2} natural dry scrubbing capability when the free calcium oxide content ranges between 4 and 7%. Precipitator operating problems attributable to high ash resistivity can be overcome by injecting sulfur trioxide to reduce the ash resistivity, with, of course, a probable increase in operating costs. 27 refs., 7 figs., 1 tab.

  8. Influence of a Modification of the Petcoke/Coal Ratio on the Leachability of Fly Ash and Slag Produced from a Large PCC Power Plant

    SciTech Connect

    Izquierdo,M.; Font, O.; Moreno, N.; Querol, X.; Huggins, F.; Alvarez, E.; Diez, S.; Otero, P.; Ballesteros, J.; Gimenez, A.

    2007-01-01

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

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

    PubMed

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

    2007-08-01

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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Impact of the disposal and re-use of fly ash on water quality: the case of the Koradi and Khaperkheda thermal power plants (Maharashtra, India).

    PubMed

    Spadoni, M; Voltaggio, M; Sacchi, E; Sanam, R; Pujari, P R; Padmakar, C; Labhasetwar, P K; Wate, S R

    2014-05-01

    An increasing amount of fly ash from thermal power plants is produced in India every year. Its disposal is generally done in ponds after it is mixed together in suitable proportion of water to form a slurry. Fly ash from Koradi and Khaperkheda thermal power plants (Nagpur, Maharashtra) is commonly disposed in an area characterized by the presence of many small villages where the population uses the groundwater for drinking and domestic purposes. Here, the groundwater locally exceeds the concentration limits recommended by the Bureau of Indian Standards (BIS, 2005) and by the World Health Organization (WHO, 2008) for Mg(2+), Ca(2+), NO3(-), SO4(2-), Total Dissolved Solids (TDS) and for some minor elements like As, Mo, V and U. A new geological map of the study area has been prepared to understand the possible water-rock interactions. An extensive geochemical survey of groundwater, stream water and fly ash was also carried out to clarify the possible origin of the pollutants by discriminating between geogenic and anthropogenic sources and to assess the influence of the ash ponds on water quality. The analytical results suggest that a large part of the sulfates in the groundwater of the villages of Masada, Khairi and Kawatha originate from the infiltration of industrial water from tens of factories that mix fly ash with relatively high quantities of gypsum and lime for the production of bricks. In addition, the interaction with the relatively U-rich Gondwana units, like Talchir formation, is probably the cause of the high concentration of this element. Results showed how the relatively high concentrations of Mo, As, B and F in circulating waters are linked to the leaching from fly ash, also pointing out a direct spatial correlation between the concentration of fluorides in the groundwater and their closeness to the ash ponds.

  15. Identification of Chromium Resistant Bacteria from Dry Fly Ash Sample of Mejia MTPS Thermal Power Plant, West Bengal, India.

    PubMed

    Roychowdhury, Roopali; Mukherjee, Pritam; Roy, Madhumita

    2016-02-01

    Eight chromium resistant bacteria were isolated from a dry fly ash sample of DVC-MTPS thermal power plant located in Bankura, West Bengal, India. These isolates displayed different degrees of chromate reduction under aerobic conditions. According to 16S rDNA gene analysis, five of them were Staphylococcus, two were Bacillus and one was Micrococcus. The minimum inhibitory concentration towards chromium and the ability to reduce hexavalent chromium to trivalent chromium was highest in Staphylococcus haemolyticus strain HMR17. All the strains were resistant to multiple heavy metals (As, Cu, Cd, Co, Zn, Mn, Pb and Fe) and reduced toxic hexavalent chromium to relatively non toxic trivalent chromium even in the presence of these multiple heavy metals. All of them showed resistance to different antibiotics. In a soil microcosm study, S. haemolyticus strain HMR17 completely reduced 4 mM hexavalent chromium within 7 days of incubation.

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

    USGS Publications Warehouse

    Lu, Y.; Rostam-Abadi, M.; Chang, R.; Richardson, C.; Paradis, J.

    2007-01-01

    Nine fly ash samples were collected from the particulate collection devices (baghouse or electrostatic precipitator) of four full-scale pulverized coal (PC) utility boilers burning eastern bituminous coals (EB-PC ashes) and three cyclone utility boilers burning either Powder River Basin (PRB) coals or PRB blends,(PRB-CYC ashes). As-received fly ash samples were mechanically sieved to obtain six size fractions. Unburned carbon (UBC) content, mercury content, and Brunauer-Emmett-Teller (BET)-N2 surface areas of as-received fly ashes and their size fractions were measured. In addition, UBC particles were examined by scanning electron microscopy, high-resolution transmission microscopy, and thermogravimetry to obtain information on their surface morphology, structure, and oxidation reactivity. It was found that the UBC particles contained amorphous carbon, ribbon-shaped graphitic carbon, and highly ordered graphite structures. The mercury contents of the UBCs (Hg/UBC, in ppm) in raw ash samples were comparable to those of the UBC-enriched samples, indicating that mercury was mainly adsorbed on the UBC in fly ash. The UBC content decreased with a decreasing particle size range for all nine ashes. There was no correlation between the mercury and UBC contents of different size fractions of as-received ashes. The mercury content of the UBCs in each size fraction, however, generally increased with a decreasing particle size for the nine ashes. The mercury contents and surface areas of the UBCs in the PRB-CYC ashes were about 8 and 3 times higher than UBCs in the EB-PC ashes, respectively. It appeared that both the particle size and surface area of UBC could contribute to mercury capture. The particle size of the UBC in PRB-CYC ash and thus the external mass transfer was found to be the major factor impacting the mercury adsorption. Both the particle size and surface reactivity of the UBC in EB-PC ash, which generally had a lower carbon oxidation reactivity than the PRB

  17. 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.

  18. Morphological and biochemical changes in Azadirachta indica from coal combustion fly ash dumping site from a thermal power plant in Delhi, India.

    PubMed

    Qadir, Sami Ullah; Raja, Vaseem; Siddiqui, Weqar A

    2016-07-01

    The foliar and biochemical traits of Azadirachta indica A. Juss from fly ash (FA) dumping site in Badarpur thermal power plant (BTPP) New Delhi, India was studied. Three different experimental sites were selected at different distances from the thermal power plant. Ambient suspended particulate matter (SPM) and plant responses such as leaf pigments (chlorophyll a, chlorophyll b, and carotenoids), total chlorophyll, net photosynthetic rate, stomatal index (SI), stomatal conductance (SC), intercellular carbon dioxide concentration [CO2]i, net photosynthetic rate (NPR), nitrogen, nitrate, nitrate reductase activity, proline, protein, reducing sugar and sulphur content were measured. Considerable reduction in pigments (chlorophyll a, chlorophyll b and carotenoids), and total chlorophyll was observed at fly ash dumping site. Fly ash stress revealed the inhibitory effect on Nitrate reductase activity (NRA), Nitrate, soluble protein, and reducing sugar content, whereas stimulatory effect was found for the stomatal index, nitrogen, proline, antioxidants and sulphur content in the leaves. Under fly ash stress, stomatal conductance was low, leading to declining in photosynthetic rate and increase in the internal CO2 concentration of leaf. Single leaf area (SLA), leaf length and leaf width also showed a declining trend from control to the polluted site. Antioxidant enzymes increased in leaves reflecting stress and extenuation of reactive oxygen species (ROS).

  19. Pb-210 and Po-210 atmospheric releases via fly ash from oil shale-fired power plants.

    PubMed

    Vaasma, Taavi; Loosaar, Jüri; Gyakwaa, Francis; Kiisk, Madis; Özden, Banu; Tkaczyk, Alan H

    2017-03-01

    During high temperature processes in the furnace volatile and semi-volatile elements and radionuclides are partially emitted to the environment, depending on their chemical form in the original fuel, the technological set-up of the combustion system, and the prevailing combustion conditions. Two of the world's largest oil shale-fired power plants (PPs) have been operational in Estonia from the 1960s, during which time creation of significant environmental emissions and waste containing naturally occurring radionuclides has occurred. Pb-210 and (210)Po are considered natural radionuclides with the highest emission rates from PPs and possess elevated potential radiation exposure risks to humans and the environment. These radionuclides have the highest activity concentration values in fine ash fractions, especially in fractions remaining below 2.5 μm. To determine the activity concentrations of (210)Pb and (210)Po in the PPs' outlet, sampling was conducted from boilers operating on pulverized fuel (PF) technology with novel integrated desulphurization (NID) system and bag filters as well as with electrostatic precipitators (ESPs). The (210)Pb and (210)Po activity concentrations remained around 300 Bq kg(-1) for the NID system compared to 60-80 Bq kg(-1) in the ESP system. The dominant ash fraction in both systems was PM2.5, constituting over 50% of the fly ash mass collected from the outlet. The authors estimate that the total atmospherically emitted activity for the modernized PPs remains dominantly below 1% of the activity that is inserted via fuel. The implementation of higher efficiency purifications systems has significantly reduced the negative effect of these PPs. Based on annually emitted fly ash and boilers' working hours, the (210)Pb and (210)Po activity released relative to energy production were up to 68.3 kBq GWhel(-1) for (210)Pb and 64.6 kBq GWhel(-1) for (210)Po. These values are 1 to 2 orders of magnitude lower compared to the situation in the 1980s

  20. 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.

  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. 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.

  3. Simultaneous recovery of vanadium and nickel from power plant fly-ash: Optimization of parameters using response surface methodology

    SciTech Connect

    Nazari, E.; Rashchi, F. Saba, M.; Mirazimi, S.M.J.

    2014-12-15

    Highlights: • Leaching of vanadium and nickel from fly ash (14.43% V and 5.19% Ni) in sulfuric acid was performed. • Optimization of leaching parameters was carried out using a response surface methodology. • Using optimum conditions, 94.28% V and 81.01% Ni “actual recovery” was obtained. - Abstract: Simultaneous recovery of vanadium (V) and nickel (Ni), which are classified as two of the most hazardous metal species from power plant heavy fuel fly-ash, was studied using a hydrometallurgical process consisting of acid leaching using sulfuric acid. Leaching parameters were investigated and optimized in order to maximize the recovery of both vanadium and nickel. The independent leaching parameters investigated were liquid to solid ratio (S/L) (5–12.5 wt.%), temperature (45–80 °C), sulfuric acid concentration (5–25 v/v%) and leaching time (1–5 h). Response surface methodology (RSM) was used to optimize the process parameters. The most effective parameter on the recovery of both elements was found to be temperature and the least effective was time for V and acid concentration for Ni. Based on the results, optimum condition for metals recovery (actual recovery of ca.94% for V and 81% for Ni) was determined to be solid to liquid ratio of 9.15 wt.%, temperature of 80 °C, sulfuric acid concentration of 19.47 v/v% and leaching time of 2 h. The maximum V and Ni predicted recovery of 91.34% and 80.26% was achieved.

  4. 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.

  5. Effects of fly ash incorporation on heavy metal accumulation, growth and yield responses of Beta vulgaris plants.

    PubMed

    Singh, Anurag; Sharma, Rajesh Kumar; Agrawal, Shashi Bhushan

    2008-10-01

    Use of fly ash (FA) to agriculture is not always beneficial, however, utilization of lower concentration of FA as soil amendment is suitable for better management of few crops. The present study was conducted to study the effects of various concentrations of FA (0%, 5%, 10%, 15% and 20%) on heavy metal accumulation, growth, and yield responses of palak (Beta vulgaris L. var All Green H1). The results showed that application of FA caused significant reductions in growth, biomass and yield responses of B. vulgaris plants at different ages of observations. The concentrations of all the heavy metals increased significantly with increasing concentrations of FA. Metal pollution index (MPI) of both roots and shoots showed significant and negative relationships with the yield of B. vulgaris plants. The study concludes that B. vulgaris plant is sensitive to FA concentrations used in this study. It is further recommended that leafy vegetable like B. vulgaris is not a suitable crop to be grown in a region where FA is used for amendment of agricultural soils.

  6. 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.

  7. 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.

  8. 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.

  9. Impact assessment of dredging to remove coal fly ash at the Tennessee Valley Authority Kingston Fossil plant using fathead minnow elutriate exposures.

    PubMed

    Stanley, Jacob K; Kennedy, Alan J; Bednar, Anthony J; Chappell, Mark A; Seiter, Jennifer M; Averett, Daniel E; Steevens, Jeffery A

    2013-04-01

    On December 22, 2008, failure of an earthen containment structure resulted in the release of approximately 4.1 million m(3) of coal fly ash into the Emory River and the surrounding area from the Tennessee Valley Authority Kingston Fossil Plant near Kingston, Tennessee, USA. The purpose of the present study was to assess the potential of dredging activities performed to remove the fly ash from the river to result in increased risk to pelagic fish, with special consideration of mobilization of metals. Elutriates were created using two sources of fly ash by bubbling with air over 10 d. This elutriate preparation method was designed to represent worst-case conditions for oxidation, metal release, and dissolution. Larval and juvenile Pimephales promelas underwent 10-d exposures to these elutriates. Larval end points included survival and biomass, and juvenile end points included survival, length, biomass, liver somatic index, and bioaccumulation. No significant toxicity was observed. Bioaccumulation of metals in juveniles was found to be primarily attributable to metals associated with particles in the gut. Results suggest little potential for toxicity to related fish species due to fly ash removal dredging activities given the extreme conditions represented by the elutriates in the present study.

  10. 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.

  11. Ion exchange uptake of ammonium in wastewater from a Sewage Treatment Plant by zeolitic materials from fly ash.

    PubMed

    Juan, Roberto; Hernández, Susana; Andrés, José M; Ruiz, Carmen

    2009-01-30

    The potential value of zeolitic materials (ZM) obtained from a hazardous waste, such as coal fly ash, for the retention of NH(4)(+) present in liquid effluents from a Sewage Treatment Plant (STP) is studied. A wastewater sample was taken from an STP in Zaragoza (Spain) after conventional treatment at the Plant. The water was treated with different amounts of three ZM: NaP1 zeolite, K-F zeolite and K-Chabazite/K-Phillipsite zeolites all of them in powdered and granulated state. The wastewater was treated by two kinds of processes: continuous stirring batch experiments with powdered ZM, and fixed packed bed of granulated ZM in a column. The powdered materials reduced about 80% of NH(4)(+) from wastewater, even in the presence of Ca(2+), which competes with NH(4)(+) for the cation exchange sites in zeolites. Around 70% of NH(4)(+) reduction was achieved with granulated materials. In both cases, moderate ZM/wastewater ratios had to be used to achieve those results, with K-zeolites slightly less effective in NH(4)(+) retention.

  12. Building ceramics with an addition of pulverized combustion fly ash from the thermal power plant Nováky

    NASA Astrophysics Data System (ADS)

    Húlan, Tomáš; Trník, Anton; Medved, Igor; Štubňa, Igor; Kaljuvee, Tiit

    2016-07-01

    Pulverized combustion fly ash (PFA) from the Power plant Nováky (Slovakia) is analyzed for its potential use in the production of building ceramics. Three materials are used to prepare the mixtures: illite-rich clay (IRC), PFA and IRC fired at 1000 °C (called grog). The mixtures contain 60 % of IRC and 40 % of a non-plastic compound (grog or PFA). A various amount of the grog is replaced by PFA and the effect of this substitution is studied. Thermal analyses (TGA, DTA, thermodilatometry, and dynamical thermomechanical analysis) are used to analyze the processes occurring during firing. The flexural strength and thermal conductivity are determined at room temperature after firing in the temperature interval from 800 to 1100 °C. The results show that an addition of PFA slightly decreases the flexural strength. The thermal conductivity and porosity are practically unaffected by the presence of PFA. Thus, PFA from the Power plant Nováky is a convenient non-plastic component for manufacturing building ceramics.

  13. 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.

  14. 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.

  15. Impairment of soil health due to fly ash-fugitive dust deposition from coal-fired thermal power plants.

    PubMed

    Raja, R; Nayak, A K; Shukla, A K; Rao, K S; Gautam, Priyanka; Lal, B; Tripathi, R; Shahid, M; Panda, B B; Kumar, A; Bhattacharyya, P; Bardhan, G; Gupta, S; Patra, D K

    2015-11-01

    Thermal power stations apart from being source of energy supply are causing soil pollution leading to its degradation in fertility and contamination. Fine particle and trace element emissions from energy production in coal-fired thermal power plants are associated with significant adverse effects on human, animal, and soil health. Contamination of soil with cadmium, nickel, copper, lead, arsenic, chromium, and zinc can be a primary route of human exposure to these potentially toxic elements. The environmental evaluation of surrounding soil of thermal power plants in Odisha may serve a model study to get the insight into hazards they are causing. The study investigates the impact of fly ash-fugitive dust (FAFD) deposition from coal-fired thermal power plant emissions on soil properties including trace element concentration, pH, and soil enzymatic activities. Higher FAFD deposition was found in the close proximity of power plants, which led to high pH and greater accumulation of heavy metals. Among the three power plants, in the vicinity of NALCO, higher concentrations of soil organic carbon and nitrogen was observed whereas, higher phosphorus content was recorded in the proximity of NTPC. Multivariate statistical analysis of different variables and their association indicated that FAFD deposition and soil properties were influenced by the source of emissions and distance from source of emission. Pollution in soil profiles and high risk areas were detected and visualized using surface maps based on Kriging interpolation. The concentrations of chromium and arsenic were higher in the soil where FAFD deposition was more. Observance of relatively high concentration of heavy metals like cadmium, lead, nickel, and arsenic and a low concentration of enzymatic activity in proximity to the emission source indicated a possible link with anthropogenic emissions.

  16. Detection of potential genetic hazards in complex environmental mixtures using plant cytogenetics and microbial mutagenesis assays. [Arsenic-contaminated groundwater and power plant fly ash extract

    SciTech Connect

    Constantin, M J; Lowe, K; Rao, T K; Larimer, F W; Epler, J L

    1980-01-01

    Solid wastes have been characterized to determine their potential hazards to humans and the environment. An arsenic-contaminated ground water sample increased the frequency of histidine revertants in Salmonella typhimurium (TA-98) at 0.025 to 5.000 ..mu..l per plate with Aroclor-induced S-9 liver microsomes. When 2.5 to 75 ..mu..l of the XAD-2 concentrate (12.5-fold, v:v) were used, the mutant frequency was increased in strains TA-98, TA-100, and TA-1537; metabolic activation was not required. Only the XAD-2 concentrate was mutagenic in the Saccharomyces cerevisiae haploid strain XL-7-10B; metabolic activation was not required. The mutagenic principal, which is not known, appears to be at the limit of resolution; hence, the XAD-2 concentration is necessary to demonstrate mutagenic activity. The arsenic-contaminated ground water (0.0625 and 0.125 dilutions) and the power plant fly ash extract (undiluted) increased the frequency of bridges and fragements at anaphase in root tip cells of Hordeum. The fly ash sample was negative in the microbial assays. Results emphasize (1) the need for a battery of assays with different organisms and (2) the potential of a simple assay using plant root tip cells to detect mutagenic activity in complex environmental mixtures.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Characterization and environmental risk assessment of heavy metals found in fly ashes from waste filter bags obtained from a Chinese steel plant.

    PubMed

    Zhou, Yun; Ning, Xun-an; Liao, Xikai; Lin, Meiqing; Liu, Jingyong; Wang, Jianghui

    2013-09-01

    The environmental risk of exposure to six heavy metals (Cu, Pb, Zn, Cr, Ni, and Cd) found in fly ashes from waste filter bags obtained from a steel plant was estimated based on the mineralogical compositions, total concentrations and speciation of the metals in the fly ashes. The results indicated that the fly ashes mainly consisted of hematite, magnetite, cyanite, spinel, coesite and amorphous materials. The concentrations of Zn and Pb were much higher than that of other materials. After Zn and Pb, Ni was present in the highest concentration, followed by Cu, Cr and Cd. Each heavy metal was distributed differently in fly ashes. The levels of Zn, Cd and Pb in the active fraction were very high, and ranged from 64.83 to 81.96%, 34.48 to 82.4% and 6.92 to 79.65% respectively, while Cu, Cr and Ni were mainly present in the residual fraction. The risk assessment code (RAC) values of fly ashes showed that the Zn and Cd present in the H3 sample presented a very high risk, with RAC values greater than 50%. The Cu present in the H3 sample, Cd in the H2 sample and Zn in the H4 and H5 samples presented a high risk. The Pb present in the H2 sample, Cd in the H4 sample, Ni in the H1 and H5 samples, and Zn in the H1 sample presented a medium risk. A low risk was presented by the Cu present in the H1, H2, H4 and H5 samples, the Pb in the H1, H3 and H5 samples, the Cd in the H1 and H5 samples, and the Ni in the H2 sample. No risk was presented by Cr in any sample.

  2. 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.

  3. Simultaneous recovery of vanadium and nickel from power plant fly-ash: optimization of parameters using response surface methodology.

    PubMed

    Nazari, E; Rashchi, F; Saba, M; Mirazimi, S M J

    2014-12-01

    Simultaneous recovery of vanadium (V) and nickel (Ni), which are classified as two of the most hazardous metal species from power plant heavy fuel fly-ash, was studied using a hydrometallurgical process consisting of acid leaching using sulfuric acid. Leaching parameters were investigated and optimized in order to maximize the recovery of both vanadium and nickel. The independent leaching parameters investigated were liquid to solid ratio (S/L) (5-12.5 wt.%), temperature (45-80 °C), sulfuric acid concentration (5-25 v/v%) and leaching time (1-5h). Response surface methodology (RSM) was used to optimize the process parameters. The most effective parameter on the recovery of both elements was found to be temperature and the least effective was time for V and acid concentration for Ni. Based on the results, optimum condition for metals recovery (actual recovery of ca.94% for V and 81% for Ni) was determined to be solid to liquid ratio of 9.15 wt.%, temperature of 80 °C, sulfuric acid concentration of 19.47 v/v% and leaching time of 2h. The maximum V and Ni predicted recovery of 91.34% and 80.26% was achieved.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Effect of metal tolerant plant growth promoting bacteria on growth and metal accumulation in Zea mays plants grown in fly ash amended soil.

    PubMed

    Kumar, Kalpna V; Patra, D D

    2013-01-01

    The present study was undertaken to examine the effect of the application of fly ash (FA) into Garden soil (GS), with and without inoculation of plant growth promoting bacteria (PGPB), on the growth and metal uptake by Zea mays plants. Three FA tolerant PGPB strains, Pseudomonas sp. PS5, PS14, and Bacillus sp. BC29 were isolated from FA contaminated soils and assessed for their plant growth promoting features on the Z. mays plants. All three strains were also examined for their ability to solubilize phosphate and to produce Indole Acetic Acid (IAA), siderophores, and hydrogencynide acid (HCN) production. Although inoculation of all strains significantly enhanced the growth of plants at both the concentration of FA but maximum growth was observed in plants inoculated with BC29 and PS14 at low level (25%) of FA concentration. The experimental results explored the plant growth promoting features of selected strains which not only enhanced growth and biomass of plants but also protected them from toxicity of FA.

  10. 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.

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

    SciTech Connect

    Maria Izquierdo; Oriol Font; Natalia Moreno

    2007-08-01

    Co-firing of coal with inexpensive secondary fuels such as petroleum coke is expected to increase in the near future in the EU given that it may provide certain economic and environmental benefits with respect to coal combustion. However, changes in the feed fuel composition of power plants may modify the bulk content and the speciation of a number of elements in fly ash and slag. Consequently, leachability of these byproducts also can be modified. This study is focused on identifying the changes in the environmental quality of co-fired fly ash and slag induced by a modification of the petcoke/coal ratio. Petcoke was found to increase the leachable content of V and Mo and to enhance the mobility of S and As. However, with the exception of these elements, the addition of this secondary fuel did not drastically modify the bulk composition or the overall leachability of the resulting fly ash and slag. 30 refs., 3 figs., 2 tabs.

  13. 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.

  14. 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.

  15. 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.

  16. Plant materials and amendments for controlling wind and water erosion on a fly ash disposal area: TVA Colbert Fossil Plant, Alabama

    SciTech Connect

    Maddox, J.J.; Behel, D.; Soileau, J.M.; Kelsoe, J.

    1996-12-31

    Fly ash disposal sites adjacent to fossil fueled generating plants are subject to wind and water erosion which increases the operation and maintenance costs. Gullies and unstable areas in the disposal sites require expensive leveling and filling practices. Test evaluated both warm- and cool-season cover crops established by either sod or seed. Amendments to the ash consisted of composted poultry litter (CPL), soil, soil+CPL, fertilizer and beneficial soil microbes including mycorrhizal fungi. Turf sods (419 Bermuda, Emerald zoysia, and Raleigh St. Augustine) were compared in greenhouse and field studies. Six legumes and 12 grass species were tested in the greenhouse as seeded cover crops using similar amendments and raw poultry litter (PL). Legumes grew better with CPL and Boil amendments and grasses grew better on PL and soil amendments possibly due to differences in N requirements and N supply. Cool season crops generally grew faster than warm season species in the greenhouse tests. Amendments should be mixed with the FA to ameliorate the effects of boron and salt toxicity and to increase the water holding capacity. Bermuda sod grew faster than either St, Augustine or Emerald zoysia, but requires more water. A microbial amendment increased dry matter yields of bermuda sod 2 to 3 times after 40 to 60 days over unamended controls. Microbial amendments may be justified on an economic and sustainable basis. A field study is assessing the environmental and cultural requirements to grow a cover crop on an annual basis.

  17. 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.

  18. 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.

  19. 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)

  20. 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.

  1. 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 ...

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. Abundances and distribution of minerals and elements in high-alumina coal fly ash from the Jungar Power Plant, Inner Mongolia, China

    USGS Publications Warehouse

    Dai, S.; Zhao, L.; Peng, S.; Chou, C.-L.; Wang, X.; Zhang, Y.; Li, D.; Sun, Y.

    2010-01-01

    The fly ash from the Jungar Power Plant, Inner Mongolia, China, is unique because it is highly enriched in alumina (Al2O3>50%). The fly ash mainly consists of amorphous glass and mullite and trace amounts of corundum, quartz, char, calcite, K-feldspar, clay minerals, and Fe-bearing minerals. The mullite content in fly ash is as high as 37.4% because of high boehmite and kaolinite contents in feed coal. Corundum is a characteristic mineral formed during the combustion of boehmite-rich coal.Samples from the economizer were sieved into six size fractions (<120, 120-160, 160-300, 300-360, 360-500, and >500 mesh) and separated into magnetic, mullite+corundum+quartz (MCQ) and glass phases for mineralogical and chemical analysis. The corundum content increases but amorphous glass decreases with decreasing particle size. Fractions of small particle sizes are relatively high in mullite, probably because mullite was formed from fine clay mineral particles under high-temperature combustion condition. Similarly, fine corundum crystals formed in the boiler from boehmite in feed coal. The magnetic phase consists of hematite, magnetite, magnesioferrite, and MgFeAlO4 crystals. The MCQ phase is composed of 89% mullite, 6.1% corundum, 4.5% quartz, and 0.5% K-feldspar.Overall, the fly ash from the power plant is significantly enriched in Al2O3 with an average of 51.9%, but poor in SiO2, Fe2O3, CaO, MgO, Na2O, P2O5, and As. Arsenic, TiO2, Th, Al2O3, Bi, La, Ga, Ni, and V are high in mullite, and the magnetic matter is enriched in Fe2O3, CaO, MnO, TiO2, Cs, Co, As, Cd, Ba, Ni, Sb, MgO, Zn, and V. The remaining elements are high in the glass fraction. The concentration of K2O, Na2O, P2O5, Nb, Cr, Ta, U, W, Rb, and Ni do not clearly vary with particle size, while SiO2 and Hg decrease and the remaining elements clearly increase with decreasing particle size. ?? 2009 Elsevier B.V.

  11. 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)

  12. STUDY OF RADON, THORON EXHALATION AND NATURAL RADIOACTIVITY IN COAL AND FLY ASH SAMPLES OF KOTA SUPER THERMAL POWER PLANT, RAJASTHAN, INDIA.

    PubMed

    Singh, Lalit Mohan; Kumar, Mukesh; Sahoo, B K; Sapra, B K; Kumar, Rajesh

    2016-10-01

    Electricity generation in India is largely dependent on coal-based thermal power plants, and increasing demand of energy raised the coal consumption in the power plants. In recent years, study of natural radioactivity content and radon/thoron exhalation from combustion of coal and its by-products has given considerable attention as they have been recognised as one of the important technically enhanced naturally occurring radioactive materials. In the present study, radon, thoron exhalation rate and the radioactivity concentration of radionuclides in coal and fly ash samples collected from Kota Super Thermal Power Plant, Rajasthan, India have been measured and compared with data of natural soil samples. The results have been analysed and discussed.

  13. 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...

  14. 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.

  15. 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...

  16. 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.

  17. Estimation of radon exhalation rate, natural radioactivity and radiation doses in fly ash samples from Durgapur thermal power plant, West Bengal, India.

    PubMed

    Mahur, A K; Kumar, Rajesh; Sengupta, D; Prasad, Rajendra

    2008-08-01

    Coal and its by products often contain significant amounts of radionuclides, including uranium which is the ultimate source of the radioactive gas radon. Burning of coal and the subsequent emission to the atmosphere cause the re-distribution of toxic trace elements in the environment. Due to considerable economic and environmental importance and diverse uses, the collected fly ash has become a subject of worldwide interest in recent years. In the present study, radon exhalation rate and the activity concentration of (238)U, (232)Th and (40)K radionuclides in fly ash samples from Durgapur thermal power plant (WB) have been measured by "Sealed Can technique" using LR-115 type II detectors and a low level NaI (Tl) based gamma ray spectrometer, respectively. Radon exhalation rate varied from 360.0 to 470.0 mBq m(-2)h(-1) with an average value of 406.8 mBq m(-2)h(-1). Activity concentrations of (238)U ranged from 84.8 to 126.4 Bq kg(-1) with an average value of 99.3Bqkg(-1), (232)Th ranged from 98.1 to 140.5 Bq kg(-1) with an average value of 112.9 Bq kg(-1) and (40)K ranged from 267.1 to 364.9 Bq kg(-1) with an average value of 308.9 Bq kg(-1). Radium equivalent activity obtained from activity concentrations is found to vary from 256.5 to 352.8 Bq kg(-1) with an average value of 282.5 Bq kg(-1). Absorbed gamma dose rates due to the presence of (238)U, (232)Th and (40)K in fly ash samples vary in the range 115.3-158.5 nGy h(-1) with an average value of 126.4 nGy h(-1). While the external annual effective dose rate varies from 0.14 to 0.19 mSv y(-1) with an average value of 0.15 mSv y(-1), effective dose equivalent estimated from exhalation rate varies from 42.5 to 55.2 microSv y(-1) with an average value of 47.8 microSv y(-1). Values of external hazard index H(ex) for the fly ash samples studied in this work range from 0.69 to 0.96 with a mean value of 0.77.

  18. 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.

  19. 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.

  20. Analysis of metal Bioleaching from thermal power plant fly ash by Aspergillus niger 34770 culture supernatant and reduction of phytotoxicity during the process.

    PubMed

    Jadhav, Umesh U; Hocheng, Hong

    2015-01-01

    Aspergillus niger culture supernatant is used for bioleaching process. Before starting bioleaching process, fly ash was washed with distilled water. This removed 100 % sodium, 47 % (±0.45) boron, 38.07 % (±0.12) calcium, 29.89 % (±0.78) magnesium, and 11.8 % (±0.05) potassium. The pH was reduced from 10.5 to 8.5 after water washing. During bioleaching process, around 100 % metal removal was achieved in 4 h for all metals except chromium 93 % (±1.18), nickel 83 % (±0.32), arsenic 78 % (±0.52), and lead 70 % (±0.20). The process parameters including temperature, shaking speed, and solid/liquid ratio were optimized for bioleaching process. Experiments were conducted to evaluate effect of fly ash on growth of mung bean (Vigna radiata). At 20 g/100 ml fly ash concentration no germination of V. radiata seeds was observed. With an increasing concentration of untreated fly ash, a gradual decrease in root/shoot length was observed. After bioleaching process 78 % (±0.19) germination of V. radiata was observed with 20 g/100 ml fly ash. This study will help to develop an efficient process to remove the toxic metals from fly ash.

  1. 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.

  2. 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.

  3. 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.

  4. Screening of native plants and algae growing on fly-ash affected areas near National Thermal Power Corporation, Tanda, Uttar Pradesh, India for accumulation of toxic heavy metals.

    PubMed

    Dwivedi, S; Srivastava, S; Mishra, S; Dixit, B; Kumar, A; Tripathi, R D

    2008-10-30

    The present investigation was carried out to screen native plants growing in fly-ash (FA) contaminated areas near National Thermal Power Corporation, Tanda, Uttar Pradesh, India with a view to using them for the eco-restoration of the area. A total number of 17 plants (9 aquatic, 6 terrestrial and 2 algal species) were collected and screened for heavy metal (Fe, Zn, Cu, Mo, B, Si, Al, Cr, Pb, Cd, Hg and As) accumulation. Differential accumulation of various heavy metals by different species of plants was observed. Hydrilla verticillata was found to be the most efficient metal accumulator among 9 aquatic plants, Eclipta alba among 6 terrestrial plants and Phormedium papyraceum between 2 algal species. In general, the maximum levels of most metals were found in terrestrial plants while the lowest in algal species. However, translocation of the metals from root to shoot was found to be higher in aquatic plants than terrestrial ones. These results suggest that various aquatic, terrestrial and algal species of plants may be used in a synergistic way to remediate and restore the FA contaminated areas.

  5. Leaching Behavior of Selected Trace and Toxic Metals in Coal Fly Ash Samples Collected from Two Thermal Power Plants, India.

    PubMed

    Sandeep, P; Sahu, S K; Kothai, P; Pandit, G G

    2016-09-01

    Studies on leaching behavior of metals associated with coal fly ash (FA) are of great concern because of possible contamination of the aquatic environment. In the present study, leaching behavior of metals (As, Se, Cr, Pb, V, Zn, etc.) in two different FA samples (FA1 and FA2) was investigated at various pH (2-12), temperatures of leachate solution and using TCLP. At pH 2, the highest leaching was observed for Fe (21.6 and 32.8 µg/g), whereas at pH 12, Arsenic was found to have the highest leaching (1.5 and 2.4 µg/g) in FA1 and FA2. Leachate solution temperature showed a positive effect on the metal's leachability. In TCLP, most of the metal's leachability was observed to be higher than that of batch leaching tests. The present study suggests that, leaching of As and Se from FA samples can moderately affect ground/surface water quality at the study locations.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  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. 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.

  8. 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.

  9. Barley seedling growth in soils amended with fly ash or agricultural lime followed by acidification

    SciTech Connect

    Renken, R.R.; McCallister, D.L.; Tarkalson, D.D.; Hergert, G.W.; Marx, D.B.

    2006-05-15

    Calcium-rich coal combustion fly ash can be used as an amendment to neutralize soil acidity because of its oxides and carbonate content, but its aluminum content could inhibit plant growth if soil pH values fall below optimal agronomic levels. This study measured root and shoot growth of an acid-sensitive barley (Hordeum vulgare L. 'Kearney') grown in the greenhouse on three naturally acid soils. The soils were either untreated or amended with various liming materials (dry fly ash, wet fly ash, and agricultural lime) at application rates of 0, .5, 1, and 1.5 times the recommended lime requirement, then treated with dilute acid solutions to simulate management-induced acidification. Plant growth indexes were measured at 30 days after planting. Root mass per plant and root length per plant were greater for the limed treatments than in the acidified check. Root growth in the limed treatments did not differ from root growth in the original nonacidified soils. Top mass per plant in all limed soils was either larger than or not different from that in the original nonacidified soils. Based on top mass per plant, no liming material or application rate was clearly superior. Both fly ash and agricultural lime reduced the impact of subsequent acidification on young barley plants. Detrimental effects of aluminum release on plant growth were not observed. Calcium-rich fly ash at agronomic rates is an acceptable acid-neutralizing material with no apparent negative effects.

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. Role of blue green algae biofertilizer in ameliorating the nitrogen demand and fly-ash stress to the growth and yield of rice (Oryza sativa L.) plants.

    PubMed

    Tripathi, R D; Dwivedi, S; Shukla, M K; Mishra, S; Srivastava, S; Singh, R; Rai, U N; Gupta, D K

    2008-02-01

    Rice is a major food crop throughout the world; however, accumulation of toxic metals and metalloids in grains in contaminated environments is a matter of growing concern. Field experiments were conducted to analyze the growth performance, elemental composition (Fe, Si, Zn, Mn, Cu, Ni, Cd and As) and yield of the rice plants (Oryza sativa L. cv. Saryu-52) grown under different doses of fly-ash (FA; applied @ 10 and 100 tha(-1) denoted as FA(10) and FA(100), respectively) mixed with garden soil (GS) in combination with nitrogen fertilizer (NF; applied @ 90 and 120 kg ha(-1) denoted as NF(90) and NF(120), respectively) and blue green algae biofertilizer (BGA; applied @ 12.5 kg ha(-1) denoted as BGA(12.5)). Significant enhancement of growth was observed in the plants growing on amended soils as compared to GS and best response was obtained in amendment of FA(10)+NF(90)+BGA(12.5). Accumulation of Si, Fe, Zn and Mn was higher than Cu, Cd, Ni and As. Arsenic accumulation was detected only in FA(100) and its amendments. Inoculation of BGA(12.5) caused slight reduction in Cd, Ni and As content of plants as compared to NF(120) amendment. The high levels of stress inducible non-protein thiols (NP-SH) and cysteine in FA(100) were decreased by application of NF and BGA indicating stress amelioration. Study suggests integrated use of FA, BGA and NF for improved growth, yield and mineral composition of the rice plants besides reducing the high demand of nitrogen fertilizers.

  2. 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.

  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. Characterization and determination of 28 elements in fly ashes collected in a thermal power plant in Argentina using different instrumental techniques

    NASA Astrophysics Data System (ADS)

    Marrero, Julieta; Polla, Griselda; Jiménez Rebagliati, Raúl; Plá, Rita; Gómez, Darío; Smichowski, Patricia

    2007-02-01

    Different techniques were selected for comprehensive characterization of seven samples of fly ashes collected from the electrostatic precipitator of the San Nicolás thermal power plant (Buenos Aires, Argentina). Particle size was measured using laser based particle size analyzer. X-ray diffraction powder (XRD) analysis and scanning electron microscopy (SEM) were used to characterize the mineral phase present in the matrix consisting basically of aluminosilicates and large amounts of amorphous material. The predominant crystalline phases were mullite and quartz. Major and minors elements (Al, Ca, Cl, Fe, K, Mg, Na, S, Si and Ti) were detected by energy dispersive X-ray analysis (EDAX). Trace elements (As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Se, V and Zn) content was quantified by inductively coupled plasma optical emission spectrometry (ICP OES). Different acid mixtures and digestion procedures were compared for subsequent ICP OES measurements of the dissolved samples. The digestion procedures used were: i) a mixture of FH + HNO 3 + HClO 4 (open system digestion); ii) a mixture of FH + HNO 3 (MW-assisted digestion); iii) a mixture of HF and aqua regia (MW-assisted digestion). Instrumental neutron activation analysis (INAA) was employed for the determination of As, Ba, Co, Cr, Ce, Cs, Eu, Fe, Gd, Hf, La, Lu, Rb, Sb, Sc, Sm, Ta, Tb, Th, U and Yb. The validation of the procedure was performed by the analysis of two certified materials namely, i) NIST 1633b, coal fly ash and ii) GBW07105, rock. Mean elements content spanned from 41870 μg g - 1 for Fe to 1.14 μg g - 1 for Lu. The study showed that Fe (41870 μg g - 1 ) ≫ V (1137 μg g - 1 ) > Ni (269 μg g - 1 ) > Mn (169 μg g - 1 ) are the main components. An enrichment, with respect to crustal average, in many elements was observed especially for As, V and Sb that deserve particular interest from the environmental and human health point of view.

  5. Differential behaviour of combustion and gasification fly ash from Puertollano Power Plants (Spain) for the synthesis of zeolites and silica extraction.

    PubMed

    Font, O; Moreno, N; Díez, S; Querol, X; López-Soler, A; Coca, P; Peña, F García

    2009-07-15

    Coal gasification (IGCC) and pulverised coal combustion (PCC) fly ashes (FAs), obtained from two power plants fed with the carboniferous bituminous coal from Puertollano (Spain), were characterised and used as raw materials for zeolite synthesis by direct conversion (DC) and by alkaline fusion (Fu), and SiO2 extraction (Si-Ex) at laboratory scale. The Puertollano FAs are characterised by a high SiO2 content (59%) with respect to EU coal FAs. High zeolite synthesis yields were obtained from both FAs by using conventional alkaline activation. However, the Si extraction yields were very different. The results of the zeolite synthesis from the Si-bearing extracts from both FAs demonstrated that high purity zeolites with high cation exchange capacity (CEC, between 4.3 and 5.3meq/g) can be produced. The solid residue arising from Si-Ex is also a relatively high NaP1 zeolite product (CEC 2.4-2.7 meq/g) equivalent to the DC products. The zeolitic materials synthesised from both FAs by Fu showed an intermediate (between the high purity zeolites and the DC products) zeolite content with CEC values from 3.4 to 3.7 meq/g. Low leachable metal contents were obtained from high purity A and X zeolites and zeolite material synthesised by Fu for PCC FA.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Comparative Study on Synergetic Degradation of a Reactive Dye Using Different Types of Fly Ash in Combined Adsorption and Photocatalysis

    NASA Astrophysics Data System (ADS)

    Giri Babu, P. V. S.; Swaminathan, G.

    2016-09-01

    A comprehensive study was carried out on four different fly ashes used as a catalyst for the degradation of Acid Red 1 using ultraviolet rays. These fly ashes are collected from different thermal power stations located at various places in India and having different chemical compositions. Three fly ashes are from lignite-based thermal power plants, and one is from the coal-based power plant. One fly ash is classified as Class F, two fly ashes are classified as Class C and remaining one is not conforming to ASTM C618 classification. X-Ray Fluorescence analysis was used to identify the chemical composition of fly ashes and SiO2, Al2O3, CaO, Fe2O3 and TiO2 were found to be the major elements present in different proportions. Various analysis were carried out on all the fly ashes like Scanning Electron Microscopy to identify the microphysical properties, Energy Dispersive X-Ray spectroscopy to quantify the elements present in the catalyst and X-Ray Diffraction to identify the catalyst phase analysis. The radical generated during the reaction was identified by Electron paramagnetic resonance spectroscopy. The parameters such as initial pH of the dye solution, catalyst dosage and initial dye concentration which influence the dye degradation efficiency were studied and optimised. In 60 min duration, the dye degradation efficiency at optimum parametric values of pH 2.5, initial dye concentration of 10 mg/L and catalyst dosage of 1.0 g/L using various fly ashes, i.e., Salam Power Plant, Barmer Lignite Power Plant, Kutch Lignite Power Plant and Neyveli Lignite Thermal Power plant (NLTP) were found to be 40, 60, 67 and 95 % respectively. The contribution of adsorption alone was 18 % at the above mentioned optimum parametric values. Among the above four fly ash NLTP fly ashes proved to be most efficient.

  11. Developing Engineered Fuel (Briquettes) Using Fly Ash from the Aquila Coal-Fired Power Plant in Canon City and Locally Available Biomass Waste

    SciTech Connect

    H. Carrasco; H. Sarper

    2006-06-30

    The objective of this research is to explore the feasibility of producing engineered fuels from a combination of renewable and non renewable energy sources. The components are flyash (containing coal fines) and locally available biomass waste. The constraints were such that no other binder additives were to be added. Listed below are the main accomplishments of the project: (1) Determination of the carbon content of the flyash sample from the Aquila plant. It was found to be around 43%. (2) Experiments were carried out using a model which simulates the press process of a wood pellet machine, i.e. a bench press machine with a close chamber, to find out the ideal ratio of wood and fly ash to be mixed to get the desired briquette. The ideal ratio was found to have 60% wood and 40% flyash. (3) The moisture content required to produce the briquettes was found to be anything below 5.8%. (4) The most suitable pressure required to extract the lignin form the wood and cause the binding of the mixture was determined to be 3000psi. At this pressure, the briquettes withstood an average of 150psi on its lateral side. (5) An energy content analysis was performed and the BTU content was determined to be approximately 8912 BTU/lb. (6) The environmental analysis was carried out and no abnormalities were noted. (7) Industrial visits were made to pellet manufacturing plants to investigate the most suitable manufacturing process for the briquettes. (8) A simulation model of extrusion process was developed to explore the possibility of using a cattle feed plant operating on extrusion process to produce briquettes. (9) Attempt to produce 2 tons of briquettes was not successful. The research team conducted a trial production run at a Feed Mill in La Junta, CO to produce two (2) tons of briquettes using the extrusion process in place. The goal was to, immediately after producing the briquettes; send them through Aquila's current system to test the ability of the briquettes to flow through

  12. 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.

  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. [Effects of sulphur compounds on the volatile characteristics of heavy metals in fly ash from the MSW and sewage sludge co-combustion plant during the disposal process with higher temperature].

    PubMed

    Liu, Jing-Yong; Sun, Shui-Yu

    2012-11-01

    Fly ash sample was collected from a MSW co-combustion with sewage sludge plant and the volatilization of heavy metals Pb, Cd, Cu and Zn was investigated before and after the water washing of fly ash, meanwhile, the influence of adding different sulphur compounds (S, NaS, Na2 SO3, Na2 SO4) on the volatilization of heavy metals was studied. The results showed that the contents of Zn, Pb and Mn were high, the Ni content was low and the Cd content reached 29.4 mg x kg(1). The contents of Pb, Cu, Zn increased, while that of Cd reduced in the fly ash after water washing. TG-DTG curves of fly ash showed highest weight loss in ranges of 579-732 degrees C and 949-1 200 degrees C, with 690 degrees C and 1 154 degrees C as the inflection point temperatures. The volatilization of different heavy metals showed great difference in the volatilization rate, following the order of Pb > Cd > Zn > Cu, in which the volatilization rate of Pb was more than 80% and that of Cu was less than 30%. After water washing, the volatilization of different heavy metals showed great difference in the volatilization rate, with the order of Zn > Pb > Cd > Cu, in which the volatilization rate of Zn was more than 20%. With the pretreatment of adding Na2 SO3 and Na2 SO4, the evaporation rates of heavy metals (Cu, Pb, Zn, Cd) were significantly decreased. After adding S, the evaporation rate of Zn was reduced, whereas the addition of Na2S reduced the evaporation rates of Cd and Zn. The evaporation rates of the four heavy metals were all reduced after adding Na2S in the washed fly ash. The evaporation rates of Cu and Zn were reduced with addition of S and Na2SO3 and the evaporation rate of Cd was reduced by adding the four sulfides. The results can provide a basis for the harmless disposal and maximized resource utilization and recycling of fly ash.

  15. 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.

  16. 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.

  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. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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).

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

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

    SciTech Connect

    Menon, M.P.

    1991-08-01

    Application of fly ash-amended composts as manure enhances the crop yield of certain plants like corn, sorghum, collard and mustard greens. Organic compost made out of grass and leaves (home-made) is better than the commercial composts for amendment with fly ash. A 20--40% fly ash in the amended compost and a soil to ash-amended compost ratio of 3:1 are recommended for making bed for plantation. Organic compost mixed with fly ash, due to reduced porosity, will help the bed to retain water and conserve water supply to plants. Organic compost will release to the manure additional quantities of N, P, and S that are not substantially available in fly ash. It appears that chemical reaction and/or mineralization occurs during composting of fly ash with organic manure to release more N, P, K and S to the system. Potassium is more elevated in all plants grown in potted soil treated with fly ash-amended compost than in those grown in soil or soil treated with organic manure. Contrary to expectation Ca in fly ash is not effectively used by plants as the latter treated with ash- amended compost is not rich in Ca. This suggests that Ca may be tied up as insoluble CaSO{sub 4} in the manure so that it may not be bioavailable to the plant. Uptake of boron by bean, bell pepper and egg plant is considerably higher than that absorbed by corn, sorghum and greens resulting in poor yield for the former.

  10. Investigation on the utilization of coal fly ash as amendment to compost for vegetation in acid soil. Technical terminal report

    SciTech Connect

    Menon, M.P.

    1991-08-01

    Application of fly ash-amended composts as manure enhances the crop yield of certain plants like corn, sorghum, collard and mustard greens. Organic compost made out of grass and leaves (home-made) is better than the commercial composts for amendment with fly ash. A 20--40% fly ash in the amended compost and a soil to ash-amended compost ratio of 3:1 are recommended for making bed for plantation. Organic compost mixed with fly ash, due to reduced porosity, will help the bed to retain water and conserve water supply to plants. Organic compost will release to the manure additional quantities of N, P, and S that are not substantially available in fly ash. It appears that chemical reaction and/or mineralization occurs during composting of fly ash with organic manure to release more N, P, K and S to the system. Potassium is more elevated in all plants grown in potted soil treated with fly ash-amended compost than in those grown in soil or soil treated with organic manure. Contrary to expectation Ca in fly ash is not effectively used by plants as the latter treated with ash- amended compost is not rich in Ca. This suggests that Ca may be tied up as insoluble CaSO{sub 4} in the manure so that it may not be bioavailable to the plant. Uptake of boron by bean, bell pepper and egg plant is considerably higher than that absorbed by corn, sorghum and greens resulting in poor yield for the former.

  11. 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. 

  12. 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

  13. 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.

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

    EPA Science Inventory

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

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

    SciTech Connect

    Li, Q.S.; Chen, J.J.; Li, Y.C.

    2008-02-15

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

  17. Effect of coal fly ash-amended organic compost as a manure for agricultural crops

    SciTech Connect

    Ghuman, G.S.; Menon, M.P.; James, J.; Chandra, K.; Sajwan, K. )

    1991-04-01

    Coal-fired electric power plants generate large quantities of fly ash as a byproduct. In continuation of previous studies on the utilization of fly ash as an amendment to organic compost for use as a manure for agricultural crops, the authors have now determined the effects of this manure on the yield and uptake of selected elements by several plants including collard green, corn, mustard green, bell pepper, egg plant, and climbing beans. An amended compost containing 30-40% fly ash with a compost:soil ratio of 1:3 was found to be most effective to enhance the yield and nutrient uptake of most of the plants. At 20% fly ash level, no increase in yield of any of the above crops was observed. The uptake of K, Mg, Mn, and P was increased in most plants. Boron which is known to be detrimental to the growth of plants above certain level was also found to be increased in plants nourished with the manure.

  18. 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.

  19. Acoustic agglomeration of power plant fly ash: Quarterly technical report, 5 November 1986--5 February 1987

    SciTech Connect

    Reethof, G.

    1987-03-20

    High-intensity, high-efficiency sound sources are needed for acoustic agglomeration of particle-laden aerosols in power plant flues and for combustion enhancement. The theory of the linear model is reviewed and show to be in strong disagreement with experimental results. A theoretical study of the sound generation mechanism in sirens is then presented. The various sound attenuation mechanisms are reviewed and a low frequency numerical solution for the frequency response is given which includes arbitrary attenuation, dispersion, horn shape, and mean flow. Next finite-amplitude sound propagation in a horn is studied. Results are presented that agree very well with experimental data. Important nonlinear phenomena such as shock formation, acoustic saturation, and distortion of initially non-sinusoidal finite- amplitude waves are discussed. Finally, a new siren design methodology is presented, including a step-by-step discussion on hot to minimize the acoustic losses. 8 figs.

  20. Use of olive biomass fly ash in the preparation of environmentally friendly mortars.

    PubMed

    Cruz-Yusta, Manuel; Mármol, Isabel; Morales, Julián; Sánchez, Luis

    2011-08-15

    The incorporation of fly ash from olive biomass (FAOB) combustion in cogeneration plants into cement based mortars was explored by analyzing the chemical composition, mineralogical phases, particle size, morphology, and IR spectra of the resulting material. Pozzolanic activity was detected and found to be related with the presence of calcium aluminum silicates phases. The preparation of new olive biomass fly ash content mortars is effective by replacing either CaCO(3) filler or cement with FAOB. In fact, up to 10% of cement can be replaced without detracting from the mechanical properties of a mortar. This can provide an alternative way to manage the olive biomass fly ash as waste produced in thermal plants and reduce cement consumption in the building industry, and hence an economically and environmentally attractive choice.

  1. Mineralogical composition of boiler fouling and slagging deposits and their relation to fly ashes: the case of Kardia power plant.

    PubMed

    Kostakis, George

    2011-01-30

    Slagging and fouling deposits from a pulverized lignite fired steam generating unit of the Kardia power plant (West Macedonia, Greece) were mineralogically investigated. The structure and cohesion of these deposits varied, usually depending on the level height of the boiler unit where they were formed. Some of the deposits had complex phase composition. The dominant components of the deposits of the burner zone and of the lower and intermediate boiler zones were the amorphous, anhydrite and hematite, while those of the highest levels contained amorphous, and anhydrite. Furthermore, in deposits formed in various other boiler areas gehlenite, anorthite, diopside, quartz, Ca(2)SiO(4), brownmillerite and other crystalline phases were also identified, usually in low amounts or in traces. The major part of the phases constituting the deposits were formed in the boiler, since only a minor part derived from the unreacted minerals present in lignite. Anhydrite was generated from the reaction of SO(2) with CaO formed mainly by the calcination of calcite as well as from dehydration of gypsum contained in lignite, while hematite was produced mainly from the oxidation of pyrite. The calcium-containing silicates formed in the boiler were mainly the products of reactions between CaO and minerals contained in the lignite.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Predicting Water Quality Problems Associated with Coal Fly Ash Disposal Facilities Using a Trace Element Partitioning Study

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, S.; Donahoe, R. J.; Graham, E. Y.

    2006-12-01

    For much of the U.S., coal-fired power plants are the most important source of electricity for domestic and industrial use. Large quantities of fly ash and other coal combustion by-products are produced every year, the majority of which is impounded in lagoons and landfills located throughout the country. Many older fly ash disposal facilities are unlined and have been closed for decades. Fly ash often contains high concentrations of toxic trace elements such as arsenic, boron, chromium, molybdenum, nickel, selenium, lead, strontium and vanadium. Trace elements present in coal fly ash are of potential concern due to their toxicity, high mobility in the environment and low drinking water MCL values. Concern about the potential release of these toxic elements into the environment due to leaching of fly ash by acid rain, groundwater or acid mine drainage has prompted the EPA to develop national standards under the subtitle D of the Resource Conservation and Recovery Act (RCRA) to regulate ash disposal in landfills and surface impoundments. An attempt is made to predict the leaching of toxic elements into the environment by studying trace element partitioning in coal fly ash. A seven step sequential chemical extraction procedure (SCEP) modified from Filgueiras et al. (2002) is used to determine the trace element partitioning in seven coal fly ash samples collected directly from electric power plants. Five fly ash samples were derived from Eastern Bituminous coal, one derived from Western Sub-bituminous coal and the other derived from Northern Lignite. The sequential chemical extraction procedure gives valuable information on the association of trace elements: 1) soluble fraction, 2) exchangeable fraction, 3) acid soluble fraction, 4) easily reducible fraction, 5) moderately reducible fraction, 6) poorly reducible fraction and 7) oxidizable organics/sulfide fraction. The trace element partitioning varies with the composition of coal fly ash which is influenced by the

  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. 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.

  10. Application of Anova on Fly Ash Leaching Kinetics for Value Addition

    NASA Astrophysics Data System (ADS)

    Swain, Ranjita; Mohapatro, Rudra Narayana; Bhima Rao, Raghupatruni

    2016-04-01

    Fly ash is a major problem in power plant sectors as it is dumped at the plant site. Fly ash generation increases day to day due to rapid growth of steel industries. Ceramic/refractory industries are growing rapidly because of more number of steel industries. The natural resources of the ceramic/refractory raw materials are depleting with time due to its consumption. In view of this, fly ash from thermal power plant has been identified for use in the ceramic/refractory industries after suitable beneficiation. In this paper, sample was collected from the ash pond of Vedanta. Particle size (d80 passing size) of the sample is around 150 micron. The chemical analysis of the sample shows that 3.9 % of Fe2O3 and CaO is more than 10 %. XRD patterns show that the fly ash samples consist predominantly of the crystalline phases of quartz, hematite and magnetite in a matrix of aluminosilicate glass. Leaching of iron oxide is 98.3 % at 3 M HCl concentration at 90 °C for 270 min of leaching time. Kinetic study on leaching experiment was carried out. ANOVA software is utilized for curve fitting and the process is optimized using MATLAB 7.1. The detailed study of properties for ceramic material is compared with the standard ceramic materials. The product contains 0.3 % of iron. The other properties of the product have established the fact that the product obtained can be a raw material for ceramic industries.

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

    SciTech Connect

    Yunusa, I.A.M.; Burchett, M.D.; Manoharan, V.; DeSilva, D.L.; Eamus, D.; Skilbeck, C.G.

    2009-07-15

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

  12. Evaluation of genotoxicity of coal fly ash in Allium cepa root cells by combining comet assay with the Allium test.

    PubMed

    Chakraborty, Rajarshi; Mukherjee, Ashit Kumar; Mukherjee, Anita

    2009-06-01

    Fly ash is a by-product of coal-fired electricity generation plants. Its utilization and disposal is of utmost importance. Using onion (Allium cepa) root tip system, the present study was carried out to evaluate the potential toxic and genotoxic effects of fly ash, collected from a thermal power plant in West Bengal, India. Prior to testing, the collected fly ash sample was mixed with sand in different proportions. Allium bulbs were allowed to germinate directly in fly ash and after five days the germinating roots were processed for the Allium test. Additionally, the Allium test was adapted for detecting DNA damage through comet assay. The results from the Allium test indicate that fly ash at 100% concentration inhibits root growth and mitotic indices; induces binucleated cells as a function of the proportion, but is not toxic at very low concentration. In the comet assay, a statistical increase for DNA strand breaks was found only at higher concentrations. The sample was analyzed by flame atomic absorption spectrometer for Zn, Pb, Cu, Ni, Cd and As, whose presence could partly be responsible for the toxicity of fly ash. The study concludes that the classical Allium test can give a more comprehensive data when done in combination with the comet assay, which is faster, simpler and independent of mitosis. Also when fly ash is used for other purposes in combination with soils, it should be judiciously used at very low concentrations in order to protect the ecosystem health from any potential adverse effects.

  13. Growth and elemental accumulation of plants grown in acidic soil amended with coal fly ash-sewage sludge co-compost.

    PubMed

    Wong, Jonathan W C; Selvam, Ammaiyappan

    2009-10-01

    A greenhouse experiment was conducted to evaluate the growth and heavy-metal accumulation of Brassica chinensis and Agropyron elongatum in 10 and 25% ash-sludge co-compost (ASC)--amended loamy acidic soil (pH 4.51) at two different application rates: 20% and 40% (v/v). Soil pH increased, whereas electrical conductivity decreased with the amendment of ASC to soil. Bioavailable Cu, Zn, and Mn contents of ASC-amended soil decreased, whereas Ni, Pb, and B contents increased. Concentrations of bioavailable Cu, Zn, and Mn in sludge compost (SC)-amended soils were 5.57, 20.8, and 8.19 mg kg(-1), respectively. These concentrations were significantly lower than those in soil receiving an application rate of 20 or 25% ASC as 2.64, 8.48, and 5.26 mg kg(-1), respectively. Heavy metals and B contents of the composting mass significantly increased with an increase in ASC application rate from 20 to 40% (6.2 to 16.6 mg kg(-1) for 10% ASC- and 9.4 to 18.6 mg kg(-1) for 25% ASC-amended soil. However, when the ash content in co-compost increased from 10 to 25% during composting, bioavailable heavy-metal contents decreased. However, B contents increased with an increase in ash content. Addition of co-composts increased the dry-weight yield of the plants, and this increase was more obvious as the ash amendment rate in the co-composts and the ASC application rate increased. In case of B. chinensis, the biomass of 2.84 g/plant for 40% application of 25% ASC was significantly higher than SC (0.352 g/plant), which was 40% application of 10% ASC (0.434 g/plant) treatments. However, in A. elongatum, the differences between biomass of plants grown with 10% (1.34-1.94 g/ plant) and 25% ASC (2.12-2.21 g/plant) were not significantly different. Furthermore, there were fewer plant-available heavy metals in 25% ASC, which decreased the uptake of heavy metals by plants. ASC was favorable in increasing the growth of B. chinensis and A. elongatum. The optimal ash amendment to the sludge composting

  14. 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.

  15. 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

  16. Studies on synthesis and characteristics of zeolite prepared from Indian fly ash.

    PubMed

    Prasad, Bably; Maity, Sudip; Sangita, Kumari; Mahato, Arun Kumar; Mortimer, Robert J G

    2012-01-01

    In the present study, samples of coal fly ash were obtained from seven major Indian thermal power plants. These samples were transformed into fly ash zeolite (FAZ) using hydrothermal activation by treatment with NaOH. All experiments were carried out at 100 degrees C, but with different solid:liquid ratios, different concentrations of alkali and different incubation times. The chemical composition, mineralogy and morphology of the fly ash and FAZ were determined by wet chemical method after Na2CO3 fusion, x-ray diffraction and scanning electron microscopy. The cation exchange capacity of fly ash and FAZ was determined using the ammonium acetate method (IS:2720). The ammonium exchange capacity was determined by the titrimetric method. The experiments demonstrate that zeolite can be synthesized at 100 degrees C using alkali. The cation exchange capacity and ammonium adsorption capacity of FAZ (up to 250 meq/100 g and 22.93 mg NH4+/g respectively) indicate that the FAZ may be potentially useful to reduce heavy metals and other pollutants from contaminated environments. Therefore, zeolitization at low temperature potentially allows waste fly ash to be used in an economically advantageous way.

  17. 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.

  18. 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.

  19. 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.

  20. 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).

  1. 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.

  2. 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

  3. Growth and elemental accumulation of plants grown in acidic soil amended with coal fly ash-sewage sludge co-compost

    SciTech Connect

    Wong, J.W.C.; Selvam, A.

    2009-10-15

    A greenhouse experiment was conducted to evaluate the growth and heavy-metal accumulation of Brassica chinensis and Agropyron elongatum in 10 and 25% ash-sludge co-compost (ASC)-amended loamy acidic soil (pH 4.51) at two different application rates: 20% and 40% (v/v). Soil pH increased, whereas electrical conductivity decreased with the amendment of ASC to soil. Bioavailable Cu, Zn, and Mn contents of ASC-amended soil decreased, whereas Ni, Pb, and B contents increased. Concentrations of bioavailable Cu, Zn, and Mn in sludge compost (SC)-amended soils were 5.57, 20.8, and 8.19 mg kg{sup -1}, respectively. These concentrations were significantly lower than those in soil receiving an application rate of 20 or 25% ASC as 2.64, 8.48, and 5.26 mg kg(-1), respectively. Heavy metals and B contents of the composting mass significantly increased with an increase in ASC application rate from 20 to 40% (6.2 to 16.6 mg kg{sup -1} for 10% ASC- and 9.4 to 18.6 mg kg{sup -1} for 25% ASC-amended soil. However, when the ash content in co-compost increased from 10 to 25% during composting, bioavailable heavy-metal contents decreased. However, B contents increased with an increase in ash content. Addition of co-composts increased the dry-weight yield of the plants, and this increase was more obvious as the ash amendment rate in the co-composts and the ASC application rate increased. In case of B. chinensis, the biomass of 2.84 g/plant for 40% application of 25% ASC was significantly higher than SC (0.352 g/plant), which was 40% application of 10% ASC (0.434 g/plant) treatments. However, in A. elongatum, the differences between biomass of plants grown with 10% (1.34-1.94 g/ plant) and 25% ASC (2.12-2.21 g/plant) were not significantly different. ASC was favorable in increasing the growth of B. chinensis and A. elongatum. The optimal ash amendment to the sludge composting and ASC application rates were at 25 and 20%, respectively.

  4. Recycling seal-coat pavements with self-cementing fly ash. Phase 2, final report

    SciTech Connect

    Ferguson, E.G.

    1989-09-05

    The study evaluated the feasibility of recycling existing chip-seal pavements through stabilization with self-cementing fly ash. It was proposed that an existing pavement could be pulverized in place, sufficient quantities of Class C fly ash added, and the resulting mixture be compacted, providing a stabilized base having greater support capacity than the original pavement section. The Phase II program expanded the Phase I laboratory evaluation of stabilized, recycled material, with the focus of the testing being directed at three field projects. The field test sections were selected in regions having different sources of Class C fly ash; the three sources selected were conventional fossil fuel plants using subbituminous, low sulfur coal. The amount of gravel and asphaltic bound particles in the recycled material influenced the degree of stabilization achieved but to a lesser degree than the condition and amount of fines.

  5. INVESTIGATION OF AMMONIA ADSORPTION ON FLY ASH DUE TO INSTALLATION OF SELECTIVE CATALYTIC REDUCTION SYSTEMS

    SciTech Connect

    G.F. Brendel; J.E. Bonetti; R.F. Rathbone; R.N. Frey Jr.

    2000-11-01

    This report summarizes an investigation of the potential impacts associated with the utilization of selective catalytic reduction (SCR) systems at coal-fired power plants. The study was sponsored by the U.S. Department of Energy Emission Control By-Products Consortium, Dominion Generation, the University of Kentucky Center for Applied Energy Research and GAI Consultants, Inc. SCR systems are effective in reducing nitrogen oxides (NOx) emissions as required by the Clean Air Act (CAA) Amendments. However, there may be potential consequences associated with ammonia contamination of stack emissions and combustion by-products from these systems. Costs for air quality, landfill and pond environmental compliance may increase significantly and the marketability of ash may be seriously reduced, which, in turn, may also lead to increased disposal costs. The potential impacts to air, surface water, groundwater, ash disposal, ash utilization, health and safety, and environmental compliance can not be easily quantified based on the information presently available. The investigation included: (1) a review of information and data available from published and unpublished sources; (2) baseline ash characterization testing of ash samples produced from several central Appalachian high-volatile bituminous coals from plants that do not currently employ SCR systems in order to characterize the ash prior to ammonia exposure; (3) an investigation of ammonia release from fly ash, including leaching and thermal studies; and (4) an evaluation of the potential impacts on plant equipment, air quality, water quality, ash disposal operations, and ash marketing.

  6. An ecophysiological study of plants growing on the fly ash deposits from the "Nikola Tesla-A" thermal power station in Serbia.

    PubMed

    Pavlović, Pavle; Mitrović, Miroslava; Djurdjević, Lola

    2004-05-01

    This ecophysiological research on the ash deposits from the "Nikola Tesla-A" thermal power station in Serbia covered 10 plant species (Tamarix gallica, Populus alba, Spiraea van-hauttei, Ambrosia artemisifolia, Amorpha fruticosa, Eupatorium cannabinum, Crepis setosa, Epilobium collinum, Verbascum phlomoides, and Cirsium arvense). This paper presents the results of a water regime analysis, photosynthetic efficiency and trace elements (B, Cu, Mn, Zn, Pb, and Cd) content in vegetative plant parts. Water regime parameters indicate an overall stability in plant-water relations. During the period of summer drought, photosynthetic efficiency (Fv/Fm) was low, ranging from 0.429 to 0.620 for all the species that were analyzed. An analysis of the tissue trace elements content showed a lower trace metal concentration in the plants than in the ash, indicating that heavy metals undergo major concentration during the combustion process and some are not readily taken up by plants. The Zn and Pb concentrations in all of the examined species were normal whereas Cu and Mn concentrations were in the deficiency range. Boron concentrations in plant tissues were high, with some species even showing levels of more than 100 microg/g (Populus sp., Ambrosia sp., Amorpha sp., and Cirsium sp.). The presence of Cd was not detected. In general, it can be concluded from the results of this research that biological recultivation should take into account the existing ecological, vegetation, and floristic potential of an immediate environment that is abundant in life forms and ecological types of plant species that can overgrow the ash deposit relatively quickly. Selected species should be adapted to toxic B concentrations with moderate demands in terms of mineral elements (Cu and Mn).

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Recovery of metal oxides from fly ash. Volume 3. Commercial facility design criteria. Final report

    SciTech Connect

    Wilder, R.F.; Barrett, P.J.; Henslee, L.W. Jr.

    1984-06-01

    An engineering, cost and financial evaluation study was carried out for a conceptual commercial plant to process fly ash into marketable metal oxides by the direct HCl acid leach process. The proposed plant site was adjacent to the TVA Kingston, Tennessee power plant and was sized to process 1 million tons of ash (dry basis) per year. The capital cost requirements for the HCl direct acid leach (DAL) optimized process plant were estimated to be $244,390,000. Based upon the reported Kingston plant fly ash analysis and extractability, the conceptual commercial plant would annually produce about 158,000 TPY of alumina, 102,000 TPY of ferric oxide, 46,000 TPY of gypsum, 81,000 TPY of alkali sulfate salts, 866,000 TPY of spent fly ash and 1,940,000 kWh of excess cogeneration power. Potential long term average revenues were projected to be $126,400,000 per year which would indicate a commercial project's economics may be quite adequate. Volume 1 of this study report presents the investment and operating cost data, revenue considerations and an evaluation of profitability. Volume 2 presents the engineering data and capital cost estimates and Volume 3 presents the commercial facility design criteria. 16 references, 14 figures, 4 tables.

  12. Recovery of metal oxides from fly ash. Volume 2. Engineering data and cost estimates. Final report

    SciTech Connect

    Wilder, R.F.; Barrett, P.J.; Henslee, L.W. Jr.

    1984-06-01

    An engineering, cost and financial evaluation study was carried out for a conceptual commercial plant to process fly ash into marketable metal oxides by the direct HCl acid leach process. The proposed plant site was adjacent to the TVA Kingston, Tennessee power plant and was sized to process 1 million tons of ash (dry basis) per year. The capital cost requirements for the HCl direct acid leach (DAL) optimized process plant were estimated to be $244,390,000. Based upon the reported Kingston plant fly ash analysis and extractability, the conceptual commercial plant would annually produce about 158,000 TPY of alumina, 102,000 TPY of ferric oxide, 46,000 TPY of gypsum, 81,000 TPY of alkali sulfate salts, 866,000 TPY of spent fly ash and 1,940,000 kWh of excess cogeneration power. Potential long term average revenues were projected to be $126,400,000 per year which would indicate a commercial project's economics may be quite adequate. Volume 1 of this study report presents the investment and operating cost data, revenue considerations and an evaluation of profitability. Volume 2 presents the engineering data and capital cost estimates and Volume 3 presents the commercial facility design criteria. 16 references, 3 figures, 2 tables.

  13. Recovery of metal oxides from fly ash. Volume 1. Executive summary - financial evaluation. Final report

    SciTech Connect

    Wilder, R.F.; Barrett, P.J.; Henslee, L.W. Jr.; Arpi, D.

    1984-06-01

    An engineering, cost and financial evaluation study was carried out for a conceptual commercial plant to process fly ash into marketable metal oxides by the direct HCl acid leach process. The proposed plant site was adjacent to the TVA Kingston, Tennessee power plant and was sized to process 1 million tons of ash (dry basis) per year. The capital cost requirements for the HCl direct acid leach (DAL) optimized process plant were estimated to be $244,390,000. Based upon the reported Kingston plant fly ash analysis and extractability, the conceptual commercial plant would annually produce about 158,000 TPY of alumina, 102,000 TPY of ferric oxide, 46,000 TPY of gypsum, 81,000 TPY of alkali sulfate salts, 866,000 TPY of spent fly ash and 1,940,000 kWh of excess cogeneration power. Potential long term average revenues were projected to be $126,400,000 per year which would indicate a commercial project's economics may be quite adequate. Volume 1 of this study report presents the investment and operating cost data, revenue considerations and an evaluation of profitability. Volume 2 presents the engineering data and capital cost estimates and Volume 3 presents the commercial facility design criteria. 16 references, 16 figures, 20 tables.

  14. Behavior study of trace elements in pulverized lignite, bottom ash, and fly ash of Amyntaio power station, Greece.

    PubMed

    Megalovasilis, Pavlos; Papastergios, Georgios; Filippidis, Anestis

    2013-07-01

    The Kozani-Ptolemais-Amyntaio basin constitutes the principal coal field of Greece. Approximately 50% of the total power production of Greece is generated by five power stations operating in the area. Lignite samples, together with the corresponding fly ash and bottom ash were collected, over a period of 3 months, from the power plant of Amyntaio and analyzed for their content in 16 trace elements. The results indicate that Y, Nb, U, Rb, Zr, Ni, Pb, Ba, Zn, Sr, Cu, and Th demonstrate an organic affinity during the combustion of lignite, while V has an inorganic affinity. Three elements (Co, Cr, and Sc) show an intermediate affinity.

  15. Optimum reaction ratio of coal fly ash to blast furnace cement for effective removal of hydrogen sulfide.

    PubMed

    Asaoka, Satoshi; Okamura, Hideo; Kim, Kyunghoi; Hatanaka, Yuzuru; Nakamoto, Kenji; Hino, Kazutoshi; Oikawa, Takahito; Hayakawa, Shinjiro; Okuda, Tetsuji

    2017-02-01

    Reducing hydrogen sulfide concentration in eutrophic marine sediments is crucial to maintaining healthy aquatic ecosystems. Managing fly ash, 750 million tons of which is generated annually throughout the world, is another serious environmental problem. In this study, we develop an approach that addresses both these issues by mixing coal fly ash from coal-fired power plants with blast furnace cement to remediate eutrophic sediments. The purpose of this study is to optimize the mixing ratio of coal fly ash and blast furnace cement to improve the rate of hydrogen sulfide removal based on scientific evidence obtained by removal experiments and XAFS, XRD, BET, and SEM images. In the case of 10 mg-S L(-1) of hydrogen sulfide, the highest removal rate of hydrogen sulfide was observed for 87 wt% of coal fly ash due to decreased competition of adsorption between sulfide and hydroxyl ions. Whereas regarding 100 mg-S L(-1), the hydrogen sulfide removal rate was the highest for 95 wt% of coal fly ash. However, for both concentrations, the removal rate obtained by 87 wt% and 95 wt% were statistically insignificant. The crushing strength of the mixture was over 1.2 N mm(-2) when the coal fly ash mixing ratio was less than 95 wt%. Consequently, the mixing ratio of coal fly ash was optimized at 87 wt% in terms of achieving both high hydrogen sulfide removal rate and sufficient crushing strength.

  16. 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.

  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. 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.

  20. The secondary release of mercury in coal fly ash-based flue-gas mercury removal technology.

    PubMed

    He, Jingfeng; Duan, Chenlong; Lei, Mingzhe; Zhu, Xuemei

    2016-01-01

    The secondary release of mercury from coal fly ash is a negative by-product from coal-fired power plants, and requires effective control to reduce environmental pollution. Analysing particle size distribution and composition of the coal fly ash produced by different mercury removing technologies indicates that the particles are generally less than 0.5 mm in size and are composed mainly of SiO2, Al2O3, and Fe2O3. The relationships between mercury concentration in the coal fly ash, its particle size, and loss of ignition were studied using different mercury removing approaches. The research indicates that the coal fly ash's mercury levels are significantly higher after injecting activated carbon or brominating activated carbon when compared to regular cooperating-pollution control technology. This is particularly true for particle size ranges of >0.125, 0.075-0.125, and 0.05-0.075 mm. Leaching experiments revealed the secondary release of mercury in discarded coal fly ash. The concentration of mercury in the coal fly ash increases as the quantity of injecting activated carbon or brominating activated carbon increases. The leached concentrations of mercury increase as the particle size of the coal fly ash increases. Therefore, the secondary release of mercury can be controlled by adding suitable activated carbon or brominating activated carbon when disposing of coal fly ash. Adding CaBr2 before coal combustion in the boiler also helps control the secondary release of mercury, by increasing the Hg(2+) concentration in the leachate. This work provides a theoretical foundation for controlling and removing mercury in coal fly ash disposal.

  1. Cytotoxicity and genotoxicity induced by coal and coal fly ash particles samples in V79 cells.

    PubMed

    León-Mejía, Grethel; Silva, Luis F O; Civeira, Matheus S; Oliveira, Marcos L S; Machado, Miriana; Villela, Izabel Vianna; Hartmann, Andreas; Premoli, Suziane; Corrêa, Dione Silva; Da Silva, Juliana; Henriques, João Antônio Pêgas

    2016-12-01

    Exposure to coal and coal ashes can cause harmful effects in in vitro and in vivo systems, mainly by the induction of oxidative damage. The aim of this work was to assess cytotoxic and genotoxic effects using the V79 cell line treated with coal and coal fly ash particles derived from a coal power plant located in Santa Catarina, Brazil. Two coal samples (COAL11 and COAL16) and two coal fly ash samples (CFA11 and CFA16) were included in this study. COAL16 was co-firing with a mixture of fuel oil and diesel oil. The comet assay data showed that exposure of V79 cells to coal and coal fly ash particles induced primary DNA lesions. Application of lesion-specific endonucleases (FPG and ENDO III) demonstrated increased DNA effects indicating the presence of high amounts of oxidative DNA lesions. The cytokinesis-block micronucleus cytome assay analysis showed that exposure of V79 cells to high concentrations of coal and coal fly ash particles induced cytotoxic effects (apoptosis and necrosis) and chromosomal instability (nucleoplasmic bridges, nuclear buds, and micronucleus (MN) formation). These results may be associated with compounds contained in the surface of the particles as hazardous elements, ultrafine/nanoparticles, and polycyclic aromatic hydrocarbons (PAHs) which were detected in the samples. Graphical abstract ᅟ.

  2. 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.

  3. 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.

  4. Fly ash-amended compost as a manure for agricultural crops

    SciTech Connect

    Menon, M.P.; Sajwan, K.S.; Ghuman, G.S.; James, J.; Chandra, K. )

    1993-11-01

    Homemade organic compost prepared from lawn grass clippings was amended with fine fly ash collected from a coal-fired power plant (SRS 484.D. Savannah River Site, Aiken, SC) to investigate its usefulness as a manure in enhancing nutrient uptake and increasing dry matter yield in selected agricultural crops. Three treatments were compared: five crops (mustard, collard, string beans, bell pepper, and eggplant) were each grown on three kinds of soil: soil alone, soil amended with composted grass clippings, and soil amended with the mixed compost of grass clippings and 20% fly ash. The fly ash-amended compost was found to be effective in enhancing the dry matter yield of collard greens and mustard greens by 378% and 348%, respectively, but string beans, bell pepper, and eggplant did not show any significant increase in dry matter yield. Analysis of the above-ground biomass of these last three plants showed they assimilated high levels of boron, which is phytotoxic; and this may be the reason for their poor growth. Soils treated with fly ash-amended compost often gave higher concentrations than the control for K, Ca, Mg, S, Zn, and B in the Brassica crops. 18 refs., 2 figs., 5 tabs.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Synthesis of multiwalled carbon nanotubes on fly ash derived catalysts.

    PubMed

    Dunens, Oscar M; MacKenzie, Kieran J; Harris, Andrew T

    2009-10-15

    Carbon nanotubes (CNTs) are an allotrope of carbon with unique properties that make them potentially useful in a vast range of applications. However, CNTs are predominantly produced using expensive and/or nonrecyclable catalyst supports, e.g., mesoporous silica and alumina. In this work, coal combustion fly ash, a bulk waste product with limited uses, was impregnated with iron nitrate and successfully used as a substrate to produce industrial grade multiwalled carbon nanotubes (MWNTs) by fluidized bed chemical vapor deposition. CNTs were analyzed using thermogravimetric analysis, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy. The most successful catalyst trialed at 650 degrees C using ethylene as a carbon source was a 5 wt % Fe fly ash catalyst, which produced a CNT yield in respect to metal loading of approximately 82.5%. The MWNTs had outer diameters of between 12 and 20 nm with a reasonable degree of wall graphitization (I(G)/I(D) of 1.17). Advantages of utilizing fly ash as a catalyst support are its availability at low cost at the megaton scale, its high thermal stability, and suitability for use in industrial fluidized bed reactors. Potential applications for the fly ash produced CNTs include use in composite materials.

  10. 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...

  11. 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.

  12. A novel method for immobilization of heavy metals from MSW incinerator fly ash via use of Sorel cement

    SciTech Connect

    Macakova, S.; Hepworth, M.H.

    1996-12-31

    Since fly ash contains a higher concentration of toxic elements than bottom ash, it is not usually possible to deposit it in ordinary landfills. The special landfill sites (ash monofills) for ash, which do not endanger ground water supplies are both temporary and an expensive solution and are not acceptable by people who live adjacent to them. According to the United States Supreme Court decision ruling on May 2, 1994, incinerator ash from municipal combustion facilities are subject to the Resource Conservation and Recovery Act as potentially hazardous waste. In the autumn of 1993, a research program was initiated by one of the authors to employ a novel method for stabilization of the fly ash from electrostatic precipitators. The novelty of this method is that it used by-products from magnesium processing plants to prepare magnesia cement, so called Sorel cement, to stabilize fly ash from MSWI. Sorel cement is a combination of magnesium oxide and magnesium chloride, currently by-products of a combination of magnesium oxide and magnesium chloride, currently by-products of magnesium processing operations. The main goal of this research program was to treat fly ash prior to its disposal and to investigate the possibility of utilizing a new ash-concrete product.

  13. 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.

  14. Modification of coal fly ash size distribution. Annual technical progress report No. 1, August 1, 1980-July 31, 1981

    SciTech Connect

    Clark, R.D.; Sveum, L.K.

    1981-09-29

    A study of coal fly ash formation was initiated on August 1, 1980. The specific objectives of the study are to modify coal fly ash particle size distribution by changes in furnace gas composition and additives to the coal. Coal from four power plants and ash from 14 power plants has been obtained for use in this project. A laboratory scale coal combustor has been constructed using a two-inch tube furnace as the heat source. Ash samples may be collected on a point-to-plane electrostatic precipitator, a cascade impactor, or a cyclone train for particle sizing and characterization. Fly ash particles varying from rock fragments at low burner temperature to solid spheres and cenospheres at high temperatures have been obtained with the laboratory burner. Fundamental studies of the thermal properties of fly ash and fly ash minerals are being conducted by differential thermal analysis (DTA). The DTA traces in general are quite complexas might be expected if the ash is composed of a variety of minerals; however, the DTA traces can be characterized as having an initial exotherm with a peak at 500 to 600/sup 0/ followed by a broad endotherm with a valley in the 1000 to 1500/sup 0/ range. The endotherm has a number of small exotherms superimposed on it. Some generalizations can be made: when coal from the same mine is burned in different combustors, the thermal behavior of the ash is very similar. Ash obtained from different coal sources has different melting behavior. A subtle shift of peaks to higher temperature with larger ash particle size has been observed. 7 references, 6 figures, 7 tables.

  15. Quality assurance project plan for the Chestnut Ridge Fly Ash Pond Stabilization Project at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    SciTech Connect

    1996-07-01

    The Chestnut Ridge Fly Ash Pond Stabilization (CRFAPS) Project will stabilize a 19-m-high (62-ft-high) earthen embankment across Upper McCoy Branch situated along the southern slope of Chestnut Ridge. This task will be accomplished by raising the crest of the embankment, reinforcing the face of the embankment, removing trees from the face and top of the embankment, and repairing the emergency spillway. The primary responsibilities of the team members are: Lockheed Martin Energy Systems, Inc., (Energy Systems) will be responsible for project integration, technical support, Title 3 field support, environmental oversight, and quality assurance (QA) oversight of the project; Foster Wheeler Environmental Corporation (FWENC) will be responsible for design and home office Title 3 support; MK-Ferguson of Oak Ridge Company (MK-F) will be responsible for health and safety, construction, and procurement of construction materials. Each of the team members has a QA program approved by the US Department of Energy (DOE) Oak Ridge Operations. This project-specific QA project plan (QAPP), which is applicable to all project activities, identifies and integrates the specific QA requirements from the participant`s QA programs that are necessary for this project.

  16. 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.

  17. 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.

  18. Hydrothermally modified fly ash for heavy metals and dyes removal in advanced wastewater treatment

    NASA Astrophysics Data System (ADS)

    Visa, Maria; Chelaru, Andreea-Maria

    2014-06-01

    Fly ash resulted from coal burning is a waste that can be used in wastewater treatment for removal of dyes and heavy metals by adsorption. Class "F" fly ash (FA), collected from the Central Heat and Power (CHP) Plant Brasov (Romania), with oxides composition SiO2/Al2O3 over 2.4 was used for obtaining a new substrate with good adsorption capacity for dyes and heavy metals from wastewater. A new material was obtained from modified fly ash with NaOH and hexadecyltrimethylammonium bromide (HTAB) a cationic surfactant. Contact time, optimum amount of substrate and the pH corresponding to 50 mL solution of pollutants were the parameters optimized for obtaining the maximum efficiency in the adsorption process. The optimized adsorption parameters were further used in thermodynamic and kinetic studies of the adsorption processes. The adsorption kinetic mechanisms, and the substrate capacities are further discussed correlated with the surface structure (XRD), composition (EDS, FTIR), and morphology (SEM, AFM). The results indicate that the novel nano-substrate composite with fly ash modified can be used as an efficient and low cost adsorbent for simultaneous removal of dyes and heavy metals, the resulted water respects the discharge regulations.

  19. Sustainable asphalt pavement: Application of slaughterhouse waste oil and fly ash in asphalt binder

    NASA Astrophysics Data System (ADS)

    Sanchez Ramos, Jorge Luis

    Increasing energy costs, lack of sufficient natural resources and the overwhelming demand for petroleum has stimulated the development of alternative binders to modify or replace petroleum-based asphalt binders. In the United States, the petroleum-based asphalt binder is mainly used to produce the Hot Mix Asphalt (HMA). There are approximately 4000 asphalt plants that make 500 million tons of asphalt binder valued at roughly 3 billion/year. The instability of the world's oil market has pushed oil prices to more than 80 per barrel in 2012, which increased the cost of asphalt binder up to $570 per ton. Therefore, there is a timely need to find alternative sustainable resources to the asphalt binder. This paper investigates the possibility of the partial replacement of the asphalt binder with slaughterhouse waste and/or fly ash. In order to achieve this objective, the asphalt binder is mixed with different percentages of waste oil and/or fly ash. In order to investigate the effect of these additives to the performance of the asphalt binder, a complete performance grade test performed on multiple samples. The results of the performance grade tests are compared with a control sample to observe how the addition of the waste oil and/or fly ash affects the sample. Considering the increasing cost and demand of asphalt, the use of slaughterhouse waste oil and/or fly ash as a partial replacement may result in environmental and monetary improvements in the transportation sector.

  20. Thermal treatment and utilization of Al-rich waste in high calcium fly ash geopolymeric materials

    NASA Astrophysics Data System (ADS)

    Chindaprasirt, Prinya; Rattanasak, Ubolluk; Vongvoradit, Pimdao; Jenjirapanya, Supichart

    2012-09-01

    The Al-rich waste with aluminium and hydrocarbon as the major contaminant is generated at the wastewater treatment unit of a polymer processing plant. In this research, the heat treatment of this Al-rich waste and its use to adjust the silica/alumina ratio of the high calcium fly ash geopolymer were studied. To recycle the raw Al-rich waste, the waste was dried at 110°C and calcined at 400 to 1000°C. Mineralogical analyses were conducted using X-ray diffraction (XRD) to study the phase change. The increase in calcination temperature to 600, 800, and 1000°C resulted in the phase transformation. The more active alumina phase of active γ-Al2O3 was obtained with the increase in calcination temperature. The calcined Al-rich waste was then used as an additive to the fly ash geopolymer by mixing with high calcium fly ash, water glass, 10 M sodium hydroxide (NaOH), and sand. Test results indicated that the calcined Al-rich waste could be used as an aluminium source to adjust the silica/alumina ratio and the strength of geopolymeric materials. The fly ash geopolymer mortar with 2.5wt% of the Al-rich waste calcined at 1000°C possessed the 7-d compressive strength of 34.2 MPa.

  1. Evaluation of leaching and ecotoxicological properties of sewage sludge-fly ash mixtures

    SciTech Connect

    C.A. Papadimitriou; I. Haritou; P. Samaras; A.I. Zouboulis

    2008-03-15

    The objectives of this work were the evaluation of sewage sludge stabilization by mixing with fly ash, the examination of the physicochemical properties of the produced materials and their leachates and the assessment of their environmental impact by the evaluation of the ecotoxic characteristics. Different ratios of fly ash and sewage sludge (1:1, 1:2, 1:3, 1:6, and 1:9) were mixed for 48 and 72 h. After mixing, the liquid phase of the produced materials was analyzed for total coliforms and Escherichia coli, while the solid residue was dried and tested for the leaching characteristics by the application of TCLP and EN 12457-2 standard leaching methods. Furthermore, the produced leachates were analyzed for their content of specific metals, while their ecotoxicological characteristics were determined by the use of toxicity bioassays, using the marine photobacterium Vibrio fischeri and the crustacean Daphnia magna. The phytotoxicity of sewage sludge-fly ash mixtures was also determined by utilizing seeds of three higher plants (one monocotyl and two dicotyls). The mixtures exhibited low metal leaching in all cases, while the ecotoxic properties increased with the increase of fly ash/sewage sludge ratio. The phytotoxicity testing showed increased root length growth inhibition.

  2. Chemical characteristics and risk assessment of typical municipal solid waste incineration (MSWI) fly ash in China.

    PubMed

    Pan, Yun; Wu, Zhiming; Zhou, Jizhi; Zhao, Jun; Ruan, Xiuxiu; Liu, Jianyong; Qian, Guangren

    2013-10-15

    The release of heavy metals in municipal solid waste incineration (MSWI) fly ash has become a worrying issue while fly ash is utilized or landfilled. This work investigated the potential mobility of heavy metals in the fly ashes from 15 typical MSWI plants in Chinese mainland by the characterization of distribution, chemical speciation and leaching behavior of heavy metals. The results showed that total content of heavy metals decreased in the order Zn>Pb>Cu>Cr>Ni>Cd in samples. The toxicity characteristics leaching procedure (TCLP) of fly ash indicated that the amount of leached Cd in 67% of samples exceeded the regulated limit. Also, the excess amount of leached Zn and Pb was observed in 40% and 53% of samples, respectively. The chemical speciation analysis revealed that this excess of heavy metal leached in TCLP was contributed to the high content of acid soluble fraction (F1) and reducible fraction (F2) of heavy metal. Moreover, the great positive relevance between leaching behavior of heavy metals and F1 fraction was supported by principal component analysis (PCA). Risk assessment code (RAC) results suggested that Cd and Pb showed a very high risk class to the environment.

  3. Characterization of boron tolerant bacteria isolated from a fly ash dumping site for bacterial boron remediation.

    PubMed

    Edward Raja, Chellaiah; Omine, Kiyoshi

    2013-08-01

    Boron is an essential micronutrient for plants, but can above certain concentrations be toxic to living organisms. A major environmental concern is the removal of boron from contaminated water and fly ash. For this purpose, the samples were collected from a fly ash dumping site, Nagasaki prefecture, Japan. The chemical characteristics and heavy metal concentration of the samples were performed by X-ray fluorescent analysis and leaching test. For bacterial analysis, samples were collected in sterile plastic sheets and isolation was carried out by serial dilution method. The boron tolerant isolates that showed values of maximum inhibitory concentration toward boron ranging from 100 to 260 mM level were screened. Based on 16S rRNA sequencing and phylogenetic analysis, the isolates were most closely related to the genera Bacillus, Lysinibacillus, Microbacterium and Ralstonia. The boron tolerance of these strains was also associated with resistant to several heavy metals, such as As (III), Cr (VI), Cd, Cu, Pb, Ni, Se (III) and Zn. Indeed, these strains were arsenic oxidizing bacteria confirmed by silver nitrate test. These strains exhibited their salt resistances ranging from 4 to 15 % were determined in Trypticase soy agar medium. The boron tolerant strains were capable of removing 0.1-2.0 and 2.7-3.7 mg l(-1) boron from the medium and fly ash at 168 h. Thus, we have successfully identified the boron tolerant and removal bacteria from a fly ash dumping site for boron remediation.

  4. Mechanically activated fly ash as a high performance binder for civil engineering

    NASA Astrophysics Data System (ADS)

    Rieger, D.; Kullová, L.; Čekalová, M.; Novotný, P.; Pola, M.

    2017-01-01

    This study is aimed for investigation of fly ash binder with suitable properties for civil engineering needs. The fly ash from Czech brown coal power plant Prunerov II was used and mechanically activated to achieve suitable particle size for alkaline activation of hardening process. This process is driven by dissolution of aluminosilicate content of fly ash and by subsequent development of inorganic polymeric network called geopolymer. Hardening kinetics at 25 and 30 °C were measured by strain controlled small amplitude oscillatory rheometry with strain of 0.01 % and microstructure of hardened binder was evaluated by scanning electron microscopy. Strength development of hardened binder was investigated according to compressional and flexural strength for a period of 180 days. Our investigation finds out, that mechanically activated fly ash can be comparable to metakaolin geopolymers, according to setting time and mechanical parameters even at room temperature curing. Moreover, on the bases of long time strength development, achieved compressional strength of 134.5 after 180 days is comparable to performance of high grade Portland cement concretes.

  5. Construction Placement and Hardened Properties of Shotcrete with Highly Functional Fly Ash

    NASA Astrophysics Data System (ADS)

    Yuno, Kunihiro; Ishii, Mitsuhiro; Hashimoto, Chikanori; Mizuguchi, Hiroyuki

    Shikoku Electric Power Co., Inc. has developed the technology to manufacture a brand name "Finash" about 12 years ago, by sorting and classifying coal ash generated in coal fired power plants. "Finash" is highly functional fly ash (HFA) is produced by removing irregular coarse particles. It is important for the production of HFA to minimize the variation in quality of coal ash with sophisticated classification technique and extracting good-quality spherical fine particles. It is now widely utilized as concrete admixture for general civil engineering structures and buildings in Japan. When highly functional fly ash (HFA) is used as shotcrete admixture to substitute for fine aggregate of 100kg/m3, the shotcrete has the advantages of decreasing the amount of dust and rebound during spraying operation, improving the hardened properties of concrete, etc. Therefore, it has been applied in many tunnel construction projects. This paper discusses about the various characteristics such as construction placement, strength, neutralization and dry shrinkage of shotcrete using highly functional fly ash (HFA), using the results that is obtained from spray test in an actual road tunnel.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Investigation of the relationship between particulate-bound mercury and properties of fly ash in a full-scale 100 MWe pulverized coal combustion boiler

    SciTech Connect

    Sen Li; Chin-Min Cheng; Bobby Chen; Yan Cao; Jacob Vervynckt; Amanda Adebambo; Wei-Ping Pan

    2007-12-15

    The properties of fly ash in coal-fired boilers influence the emission of mercury from power plants into the environment. In this study, seven different bituminous coals were burned in a full-scale 100 MWe pulverized coal combustion boiler and the derived fly ash samples were collected from a mechanical hopper (MH) and an electrostatic precipitator hopper (ESP). The mercury content, specific surface area (SSA), unburned carbon, and elemental composition of the fly ash samples were analyzed to evaluate the correlation between the concentration of particulate-bound mercury and the properties of coal and fly ash. For a given coal, it was found that the mercury content in the fly ash collected from the ESP was greater than in the fly ash samples collected from the MHP. This phenomenon may be due to a lower temperature of flue gas at the ESP (about 135{sup o}C) compared to the temperature at the air preheater (about 350{sup o}C). Also, a significantly lower SSA observed in MH ash might also contribute to the observation. A comparison of the fly ash samples generated from seven different coals using statistical methods indicates that the mercury adsorbed on ESP fly ashes has a highly positive correlation with the unburned carbon content, manganese content, and SSA of the fly ash. Sulfur content in coal showed a significant negative correlation with the Hg adsorption. Manganese in fly ash is believed to participate in oxidizing volatile elemental mercury (Hg{sup 0}) to ionic mercury (Hg{sup 2+}). The oxidized mercury in flue gas can form a complex with the fly ash and then get removed before the flue gas leaves the stack of the boiler.

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

    PubMed

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

    2015-01-01

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

  12. 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

  13. 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.

  14. Use of solid waste for chemical stabilization: Adsorption isotherms and {sup 13}C solid-state NMR study of hazardous organic compounds sorbed on coal fly ash

    SciTech Connect

    Netzel, D.A.; Lane, D.C.; Rovani, J.F.; Cox, J.D.; Clark, J.A.; Miknis, F.P.

    1993-09-01

    Adsorption of hazardous organic compounds on the Dave Johnston plant fly ash is described. Fly ash from Dave Johnston and Laramie River power plants were characterized using elemental, x-ray, and {sup 29}Si NMR; the Dave Johnston (DJ) fly ash had higher quartz contents, while the Laramie River fly ash had more monomeric silicate anions. Adsorption data for hydroaromatics and chlorobenzenes indicate that the adsorption capacity of DJ coal fly ash is much less than that of activated carbon by a factor of >3000; but it is needed to confirm that solid-gas and solid-liquid equilibrium isotherms can indeed be compared. However, for pyridine, pentachlorophenol, naphthalene, and 1,1,2,2-tetrachloroethane, the DJ fly ash appears to adsorb these compounds nearly as well as activated carbon. {sup 13}C NMR was used to study the adsorption of hazardous org. cpds on coal fly ash; the nuclear spin relaxation times often were very long, resulting in long experimental times to obtain a spectrum. Using a jumbo probe, low concentrations of some hazardous org. cpds could be detected; for pentachlorophenol adsorbed onto fly ash, the chemical shift of the phenolic carbon was changed. Use of NMR to study the adsorption needs further study.

  15. Field study: Influence of fly ash on leachate composition in an excessively drained soil

    SciTech Connect

    Gangloff, W.J.; Sims, J.T.; Vasilas, B.L.; Ghodrati, M.

    1997-05-01

    Alternatives to landfilling fly ash may be to use it as a soil amendment since it is fine textured and could alter soil texture and thus improve water retention. However, fly ash contains elevated B, soluble salts, and trace element concentrations that could adversely affect plant and soil quality. Objectives were to characterize leaching of soluble salts, plant nutrients, and trace elements in a sandy soil amended with a high rate of fly ash ({approximately}662 Mg ha{sup -1}). We established Field plots in an Evesboro loamy sand using typical agricultural equipment. Lysimeters were installed to a depth of 120 cm and used to collect leachate over a 9 mo period. We also used microplots; (1.0 by 1.0 m) and similar ash rates to characterize leaching under controlled conditions. Lysimeters were installed at four depths in each microplot (15, 30, 60, and 120 cm) and water applied with a rainfall simulator. Boron and soluble salts were leached from the rooting zone after {approximately}38 cm of natural rainfall or 42 cm of irrigation. Calcium and S were the dominant plant macronutrients in leachates while Cu, Mn, and Zn were the only detectable micronutrients. Peak concentrations of these elements were detected after {approximately}50 cm of rainfall or irrigation and decreased to below or near initial concentrations by the conclusion of the study. Nickel was the only detectable trace element in leachates, however, concentrations were variable and <0.15 mg L{sup -1}. Results suggest that if fly ash incorporation is properly timed to allow for natural leaching, adverse effects will be minimal. 29 refs., 5 figs., 5 tabs.

  16. Surface modification of oil fly ash and its application in selective capturing of carbon dioxide

    NASA Astrophysics Data System (ADS)

    Yaumi, Ali L.; Hussien, Ibnelwaleed A.; Shawabkeh, Reyad A.

    2013-02-01

    Oil fly ash from power generation plants was activated with 30% NH4OH and used for selective adsorption of carbon dioxide from CO2/N2 mixture. The treated samples were characterized for their surface area, morphology, crystalline phase, chemical composition and surface functional groups. Energy dispersive X-ray analysis showed an increase in the carbon contents from 45 to 73 wt% as a result of leaching out metal oxides. XRD proved that chemical activation of ash resulted in diminishing of major crystalline phases of zeolite, and other alumino-silicates leaving only quartz and mullite. BET analysis showed an increase in surface area from 59 to 318 m2/g after chemical activation and the pore volume increased from 0.0368 to 0.679 cm3/g. This increase in pore volume is supported by the results of SEM, where more micropores were opened with well-defined particle sizes and porous structure. The TGA of the treated fly ash showed stability at higher temperature as the weight loss decreased with increasing temperature. For treated ash, the FTIR displayed new peaks of amine functional group. The treated ash was used for the removal of CO2 from CO2/N2 mixture and the maximum adsorption/capturing capacity was found to be 240 mg/g. This capacity increases with increase in initial gas concentration, inlet flow rate and temperature suggesting the endothermic nature of the interaction between the gas molecules and the surface of the ash.

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

    PubMed Central

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

    2014-01-01

    Coal ash is a byproduct of mineral coal combustion in thermal power plants. This residue is responsible for many environmental problems because it pollutes soil, water, and air. Thus, it is important to find ways to reuse it. In this study, coal fly ash, obtained from the Presidente Médici Thermal Power Plant, was utilized in the preparation of ceramic supports for the immobilization of the enzyme invertase and subsequent hydrolysis of sucrose. Coal fly ash supports were prepared at several compaction pressures (63.66–318.30 MPa) and sintered at 1200°C for 4 h. Mineralogical composition (by X-ray diffraction) and surface area were studied. The ceramic prepared with 318.30 MPa presented the highest surface area (35 m2/g) and amount of immobilized enzyme per g of support (76.6 mg/g). In assays involving sucrose inversion, it showed a high degree of hydrolysis (around 81%) even after nine reuses and 30 days' storage. Therefore, coal fly ash ceramics were demonstrated to be a promising biotechnological alternative as an immobilization support for the hydrolysis of sucrose. PMID:25110726

  18. 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%.

  19. 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.

  20. 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.

  1. The potential of Festuca rubra and Calamagrostis epigejos for the revegetation of fly ash deposits.

    PubMed

    Mitrović, Miroslava; Pavlović, Pavle; Lakusić, Dmitar; Djurdjević, Lola; Stevanović, Branka; Kostić, Olga; Gajić, Gordana

    2008-12-15

    Two grass species, Festuca rubra (sown) and Calamagrostis epigejos (naturally recolonised), were studied at two fly ash deposit lagoons, weathered 5 (L1) and 13 years (L2). Both species were assessed in terms of their invasive ability, photosynthetic efficiency, trace elements accumulation, and damage symptoms, while the characteristics of the habitat were assessed in terms of trace element content, and the pH and EC of the ash. In the ash weathered for 5 and 13 years, B and Mn concentrations fell within the normal range for soils, while there was an As, Mo and Cu excess, and Se and Zn deficit. There was no difference in the photosynthetic efficiency (ns) of the C. epigejos populations at the different-aged ash lagoons, but differences were found between the populations of F. rubra (P<0.001). F. rubra displayed damage symptoms, in the form of leaf tip chlorosis and necrosis, and wilting seedlings--a result of B accumulation in toxic concentrations and a Cu and Mn deficit. After 13 years the sown F. rubra remained over 9.5% of the ash lagoon's area (L2), while over the same period the naturally recolonised C. epigejos had overgrown 87.5% of the area. The greater colonisation and survival potential of C. epigejos is a result of multiple tolerance to the conditions at ash deposits and of the competitive ability of this species to dominate the colonised habitat. Therefore, characteristics of naturally colonised species can be used for modelling future actions of biological restoration of fly ash deposits aimed at binding the ash with minimal investment (the short-term aim), and for providing conditions for revegetation, and shortening the successive phases in the revegetation of ash deposits after the closure of thermal plants (the long-term aim).

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Atmospheric behaviour of oil-shale combustion fly ash in a chamber study

    NASA Astrophysics Data System (ADS)

    Teinemaa, Erik; Kirso, Uuve; Strommen, Michael R.; Kamens, Richard M.

    There are huge world deposits of oil shale, however, little is known about the fate of atmospheric oil-shale combustion fly ash. In the present work, oil-shale combustion fly-ash aerosol was investigated under simulated daytime and nighttime conditions. Fly-ash particles collected from the Baltic Power Plant (Estonia) were injected directly to a 190 m 3 outdoor Teflon film chamber. The initial concentration of particles was in the range from 15 to 20 mg/m 3. Particle size distributions were monitored continuously by various optical and electrical devices. During the course of an experiment the particle phase was collected on filters, and the gas phase was collected using denuders. The initial aerosol mass concentration decreased quickly due to the deposition of larger particles. Since fine particles dominated the count distribution, the change in aerosol number concentration was less significiant than the mass concentration over time. Experimental data showed a bimodal particle size distribution with maximums at about 0.07 and 4 μm. SEM images of aerosol particles also provided particle shape and size distribution information. The respirable fraction of particles, which contributes most to the health effects of the aerosol, significantly increased during the experiment, being 25% by mass immediately after the injection of fly ash and achieving 65% at the end of the experiment. Results of CG/MS analysis confirm the presence of different polycyclic aromatic hydrocarbons (PAHs) in the particle phase of the aerosol. Some of the individual compounds included phenanthrene, fluoranthene, pyrene, benz(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, and benzo(a)pyrene. Several PAHs were found in the gas phase of the chamber after fly ash had aged for 2 h, indicating that PAHs desorbed from the particles over time.

  7. Rheological analysis of an effect of different deflocculants on the fly-ash slurry

    NASA Astrophysics Data System (ADS)

    Sarnecki, K.; Bartosik, A.

    2014-08-01

    During the combustion of coal in the combined heat and power plant (CHP), a very large amount of combustion waste, called further as a fly-ash, is produced. It is typical that fly-ash appears during the combustion process of the fine coal and is transported by a pipeline with support of water as a carrier liquid to a pond storage site, where it is disposed. The pond is localized usually a few kilometers from the CHP, which makes it possible that decrease of friction in such a pipeline can result in energy savings of electricity needed for the pump and water needed as a carrier liquid. In the study an efficient method using a few deflocculants for reducing shear stress, and as a consequence viscosity, is demonstrated. The objective of the paper is to improve the efficiency of the hydrotransport of the fly-ash slurry by adding own designed additives. During the experiments a solids concentration by weight was determined from procured raw material in order to compute the real value occurring in industrial conditions. In addition, the analysis of the particle size distribution was conducted. The Anton Paar MCR 302 electronic rheometer was used to measure the dependence of shear stress and viscosity vs shear rate in the fly-ash existing in the CHP. Another part of the analysis was focused on the additives (deflocculants), to examine their influence on the reduction of the shear stress. The paper proves positive deflocculants impact on the rheological properties of the fly-ash slurry. The results of measurements are presented as figures and conclusions.

  8. Stability of solid-phase selenium species in fly ash after prolonged submersion in a natural river system.

    PubMed

    Chappell, Mark A; Seiter, Jennifer M; Bednar, Anthony J; Price, Cynthia L; Averett, Daniel; Lafferty, Brandon; Tappero, Ryan; Stanley, Jacob S; Kennedy, Alan J; Steevens, Jeffery A; Zhou, Pingheng; Morikawa, Eizi; Merchan, Gregory; Roy, Amitava

    2014-01-01

    Selenium (Se) chemistry can be very complex in the natural environment, exhibiting different valence states (-2, 0, +4, +6) representing multiple inorganic, methylated, or complexed forms. Since redox associated shifts among most of known Se species can occur at environmentally relevant conditions, it is important to identify these species in order to assess their potential toxicity to organisms. In June of 2009, researchers from the US Army Engineer Research & Development Center (ERDC) conducted investigations of the fly ash spilled 6 months previously into the Emory River at the TVA Kingston Fossil Plant, TN. Ash samples were collected on site from both the original ash pile (that did not move during the levee failure), from the spill zone (including the Emory River), and from the ash recovery ditch (ARD) containing ash removed during dredging cleanup operations. The purpose of this work was to determine the state of Se in the spilled fly ash and to assess its potential for transformation and resultant chemical stability from its prolonged submersion in the river and subsequent dredging. Sequential chemical extractions suggested that the river environment shifted Se distribution toward organic/sulfide species. Speciation studies by bulk XANES analysis on fly ash samples showed that a substantial portion of the Se in the original ash pile had transformed from inorganic selenite to a mixture of Se sulfide and reduced (organo)selenium (Se(-II)) species over the 6-month period. μ-XRF mapping data showed that significant trends in the co-location of Se domains with sulfur and ash heavy metals. Ten-d extended elutriate tests (EETs) that were bubbled continuously with atmospheric air to simulate worst-case oxidizing conditions during dredging showed no discernible change in the speciation of fly ash selenium. The enhanced stability of the organo- and sulfide-selenium species coincided with the mixture of the ash material with humic materials in the river, corresponding

  9. 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.

  10. Synthesis of merlinoite from Chinese coal fly ashes and its potential utilization as slow release K-fertilizer.

    PubMed

    Li, Jing; Zhuang, Xinguo; Font, Oriol; Moreno, Natalia; Vallejo, V Ramon; Querol, Xavier; Tobias, Aurelio

    2014-01-30

    This study focuses on the synthesis of merlinoite from Chinese coal fly ashes by KOH direct conversion method, with special emphasis on the application of synthetic merlinoite as fertilizer. These fly ashes were collected from two pulverized-coal combustion (PCC) power plants in Xinjiang, Northwest China. The synthesis results are influenced by fly ash characteristics and different synthesis conditions (KOH solution concentrations, activation temperature, time, and KOH/fly ash ratios). A high quality merlinoite-rich product was synthesized under optimal activation conditions (KOH concentration of 5M, activation temperature of 150°C, activation time of 8h and KOH/fly ash ratio of 2l/kg), with a cation exchange capacity (CEC) of 160cmolkg(-1). The synthetic merlinoite is proved to be an efficient slow release K-fertilizer for plant growth, indicating that it can be widely used for high-nutrient demanding crops growing in nutrient-limited soils and for large-area poor soil amendment in opencast coal mine areas around the power plants that will substantially grow with the increasing coal combustion in Xinjiang in the near future.

  11. 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.

  12. Comparative economic analysis of three processes for mineral recovery from fly ash. Final report

    SciTech Connect

    Doring, C.

    1983-12-30

    A review of the economic analyses of the lime-soda sinter, Hichlor, and direct acid leach processes to remove metals from flyash was conducted. Aluminum, iron, and possibly titanium recovery were emphasized. Data on the metals content of fly ash were collected and analyzed based on types of coal actually burned in coal-fired power plants in each state and DOE region. Results are presented. (PSB)

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Neutron activation analysis of thermal power plant ash and surrounding area soils.

    PubMed

    Al-Masri, M S; Haddad, Kh; Alsomel, N; Sarhil, A

    2015-08-01

    Elemental concentrations of As, Cd, Co, Cr, Fe, Hg, Mo, Ni, Se, and Zn have been determined in fly and bottom ash collected from Syrian power plants fired by heavy oil and natural gas using instrumental neutron activation analysis. The results showed that all elements were more concentrated in fly ash than in the fly ash; there was a clear increasing trend of the elemental concentrations in the fly ash along the flue gas pathway. The annual emission of elements was estimated. Elemental concentrations were higher inside the campus area than in surrounding areas, and the lowest values were found in natural-gas-fired power plant. In addition, the levels have decreased as the distance from power plant campus increases. However, the levels in the surrounding villages were within the Syrian standard for agriculture soil.

  18. EVALUATING THE EFFECTS OF FLY ASH EXPOSURE ON FISH EARLY LIFE STAGES: FATHEAD MINNOW EMBRYO-LARVAL TESTS

    SciTech Connect

    Greeley Jr, Mark Stephen; Elmore, Logan R; McCracken, Kitty

    2012-05-01

    On December 22, 2008, a dike containing fly ash and bottom ash in an 84-acre complex of the Tennessee Valley Authority's (TVA) Kingston Steam Plant in East Tennessee failed and released a large quantity of ash into the adjacent Emory River. Ash deposits extended as far as 4 miles upstream (Emory River mile 6) of the Plant, and some ash was carried as far downstream as Tennessee River mile 564 ({approx}4 miles downstream of the Tennessee River confluence with the Clinch River). A byproduct of coal burning power plants, fly ash contains a variety of metals and other elements which, at sufficient concentrations and in specific forms, can be toxic to biological systems. The effects of fly ash contamination on exposed fish populations depend on the magnitude and duration of exposure, with the most significant risk considered to be the effects of specific ash constituents, especially selenium, on fish early life stages. Uptake by adult female fish of fly ash constituents through the food chain and subsequent maternal transfer of contaminants to the developing eggs is thought to be the primary route of selenium exposure to larval fish (Woock and others 1987, Coyle and others 1993, Lemly 1999, Moscatello and others 2006), but direct contact of the fertilized eggs and developing embryos to ash constituents in river water and sediments is also a potential risk factor (Woock and others 1987, Coyle and others 1993, Jezierska and others 2009). To address the risk of fly ash from the Kingston spill to the reproductive health of downstream fish populations, ORNL has undertaken a series of studies in collaboration with TVA including: (1) a field study of the bioaccumulation of fly ash constituents in fish ovaries and the reproductive condition of sentinel fish species in reaches of the Emory and Clinch Rivers affected by the fly ash spill; (2) laboratory tests of the potential toxicity of fly ash from the spill area on fish embryonic and larval development (reported in the current

  19. Retention of fly ash-derived copper in sediments of the Pandu River near Kanpur, India

    NASA Astrophysics Data System (ADS)

    Ravi Chander, D. V.; Venkobachar, C.; Raymahashay, B. C.

    1994-10-01

    A coal-based thermal power plant is situated on the bank of the Pandu River, which is a tributary to the Ganges near Kanpur. River sediments downstream from the ash pond outfall are contaminated by fly ash. In order to establish the role of soils and sediments in retaining fly ash-derived heavy metals, copper was investigated as a model metal. A maximum concentration of 70 ppm Cu could be leached from the fly ash, confirming that it is a major source of this metal. Soil samples and river sediments were examined for Cu adsorption in the natural state as well as after treatment with H2O2, EDTA, and H2O2 followed by EDTA. The organic fraction of the samples was determined, and it had a major control on removal of Cu from a solution with 10-4 M initial concentration. Further characterization of organic matter indicated that with reference to natural samples, the humic acid fraction had a copper enrichment factor in the range 9.1 15.1. The factor for fulvic acids, in contrast, was between 3.5 and 5.5. This leads to the conclusion that river deposits rich in humic acids would withstand relatively high metal loads. Only when the metal input exceeds the maximum retention potential, would the metal be fractionated into the aqueous phase and act as a potential biocide.

  20. Fish Health Studies Associated with the Kingston Fly Ash Spill, Spring 2009 - Fall 2010

    SciTech Connect

    Adams, Marshall; Fortner, Allison M

    2012-05-01

    On December 22, 2008, over 4 million cubic meters of fly ash slurry was released into the Emory River when a dike surrounding a solid waste containment area at the Tennessee Valley Authority's (TVA) Kingston Fossil Plant ruptured. One component of TVA's response to the spill is a biological monitoring program to assess short- and long-term ecological responses to the ash and associated chemicals, including studies on fish health and contaminant bioaccumulation. These studies were initiated in early Spring 2009 for the purposes of: (1) documenting the levels of fly ash-associated metals in various tissues of representative sentinel fish species in the area of the fly ash spill, (2) determining if exposure to fly ash-associated metals causes short, intermediate, or long-term health effects on these sentinel fish species, (3) assessing if there are causal relationships between exposure to metals and health effects on fish, (4) evaluating, along with information from other ecological and physicochemical studies, the nature and route of contaminant transfer though food chains into higher level consumers, (5) providing important information for the Ecological Risk Assessment (ERA) for the Kingston fly ash project, and (6) serving as an important technology information transfer or model study focused on how to best evaluate the environmental effects of fly ash (and related environmental stressors), not only at the Kingston site, but also at sites on other aquatic systems where coal-fired generating stations are located. This report presents the results of the first two years of the fish health study. To date, fish health and bioaccumulation studies have been conducted from Spring 2009 though Fall 2011 and includes 6 seasonal studies: Spring 2009, Fall 2009, Spring 2010, Fall 2010, Spring 2011, and Fall 2011. Both the Spring and Fall studies have focused on 3-4 sentinel fish species that represent different feeding habits, behaviors, and home ranges. In addition to fish

  1. 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.

  2. [Characteristics and Resources of Fly Ash Particles in the Snowpack of Jinfo Mountain, Chongqing].

    PubMed

    Yu, Zheng-liang; Yang, Ping-heng; Jing, Wei-li; Yuan, Dao-xian; Ren, Kun; Li, Lin-li

    2015-12-01

    Snow can preserve the atmospheric information, which makes it become a good media in studying regional environment. Jinfo Mountain with an elevation of 2251.1 m, located at the transition zone between Sichuan basin and Yunnan-Guizhou Plateau, is deeply affected by human activities, and snowfall is the main form of precipitation during the winter. While the literature focus on single spherical particles in this area is uncommon. Five snow samples were collected, and determined morphology and chemical composition of 132 single spherical particles by the scanning electron microscope couples with energy dispersive X-ray spectrometer (SEM-EDS). Results show that snowfall in Jinfo Mountain includes the massive fly ash particles with 1.64 µm in average diameter and 1.09 in average roundness which contains smooth particles, rough particles and soot particles, accounting for 80. 31% , 14. 39% and 5.30% of statistical particles respectively. Furthermore, on the basis of chemical information obtained from EDS, the fly ash particles counted in this research can be classified into 5 types, namely, Si-dominant particles, C-dominant particles, Fe-dominant particles, Al-dominant particles and Ti-dominant particles, which make up 34.09%, 49.24%, 12.88%, 2.27% and 1.52% respectively. In conclusion, it can be inferred, based on the analysis of meteorological information, the properties of fly ash particles, and backward air mass trajectory and dispersion analysis, that C-dominant fly ash mainly comes from daily life and industry activities, Si-dominant fly ash particles may originate from the plant industry located in west Chingqing, north of Guizhou province, central of Hunan province, Zhejiang province, Jiangxi province and the west of Guangdong province, while the activities of foundry and iron or steel plants in the west of Chongqing, the north of Guizhou province and the central of Hunan province may be the main sources of Fe-dominant fly ash particles in our samples.

  3. Effects of the basicity on the comelting conditions of municipal solid waste incinerator fly ash and sewage sludge ash.

    PubMed

    Lin, Kae-Long

    2006-12-01

    In this study, the effects of the basicity on the pouring point of the municipal solid waste incinerator fly ash-sewage sludge ash mixture is investigated. Four kinds of sewage sludge ash, which were collected from several primary and secondary sewage treatment plants and were produced by different processes and sludge conditioning alternatives, were used as modifiers. The results indicate that the pouring point of the mixture increased with increasing basicity, within the range of 0.65-1.90. The pouring point is affected by the contents of the mixtures (CaO, SiO2, Al2O3, and the flux). It is suggested that an increase in the CaO content tends to raise the pouring point, whereas an increase in the SiO2 and/or the Al2O3 contents cause as adverse reaction. The prediction equation, obtained by multilinear regression (significant level is 0.05), is as follows: pouring temperature = 1189.6 + 4.19 CaO - 0.96 SiO2 - 4.33 Al2O3 (R2 = 0.91). In general, the pouring point decreased when the basicity was < 1. The pouring point apparently increased when the basicity was > 1.2. The regression squares for the different basicities were between 0.84 and 0.91. From these relationships, we note that a basicity index of 5 gave the best R2 (0.91). From the results of this study, it can be concluded that the modification of the basicity of the fly ash by the addition of sewage sludge ash to lower the pouring point is feasible and leads to a more energy-efficient melting process. In addition, these synthetic slags have a good pozzolanic reactive activity.

  4. 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).

  5. 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).

  6. 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.

  7. 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.

  8. 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.

  9. Biofunctional Characteristics of Lignite Fly Ash Modified by Humates: A New Soil Conditioner

    PubMed Central

    Chassapis, Konstantinos; Roulia, Maria; Vrettou, Evangelia; Fili, Despina; Zervaki, Monica

    2010-01-01

    Fly ash superficially modified with humic substances from the Megalopolis lignitic power plant was prepared and evaluated for agricultural uses. UV-vis spectrophotometry and IR spectroscopy revealed that fly ash shows high sorption efficiency towards humic substances. Adsorption proceeds stepwise via strong Coulombic and hydrophophic forces of attraction between guest and host materials. Langmuir, Freundlich, BET, Harkins-Jura, and Dubinin-Radushkevich isotherm models were employed to evaluate the ongoing adsorption and shed light to the physicochemical properties of the sorbent-adsorbate system. Humic substances desorption and microbial cultivation experiments were also carried out to examine the regeneration of the humates under washing and explore the possibility of this material acclimatizing in real soil conditions, both useful for biofunctional agricultural applications. PMID:20592758

  10. Preparation and Cation Exchange Properties of Zeolitic Adsorbents Using Fused Coal Fly Ash and Seawater

    NASA Astrophysics Data System (ADS)

    Hirai, Takashi; Wajima, Takaaki; Yoshizuka, Kazuharu

    For the development of functional material using coal fly ash discharged from thermal power plants, we have prepared zeolitic adsorbents derived from alkaline fused coal fly ash in several aqueous saline media to obtain the optimized preparation condition. The NH4+ exchange capacity of the product prepared at 80°C for 12 hours in diluted seawater using the precursor fused at 500°C was 4.6 mmol⁄g which is equivalent that of product prepared in deionized water. Zeolite-X and zeolite-A were produced in all aqueous media, in addition hydroxysodalite was produced over 12 hours. It was suggested that zeolite-A transform into hydroxysodalite in the products. The zeolitic adsorbents having high ion exchange capacity could be prepared in twice diluted seawater at 6-12 hours in 80°C using a precursor fused at 500°C.

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

    PubMed

    Moreno, N; Querol, X; Ayora, C; Pereira, C F; Janssen-Jurkovicová, M

    2001-09-01

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

  12. Speciation of Major and Selected Trace Elements in IGCC Fly Ash

    SciTech Connect

    Font,O.; Querol, X.; Huggins, F.; Chimenos, J.; Fernandez, A.; Burgos, S.; Pena, F.

    2005-01-01

    The speciation of Ga, Ge, Ni, V, S and Fe in fly ash from IGCC power plant were investigated for possible further extraction process by combining conventional mineral and chemical analysis, leaching tests, wet sequential extraction, Moessbauer and XAFS spectroscopies. The results shown that Ge occurs mainly as water-soluble species, GeS and/or GeS2 and hexagonal GeO2. Ga is present as an oxide, Ni occurs mainly as nickeline (NiAs), with minor proportions of Ni arsenates and vanadium as V(III) with minor amounts of V(IV) in the aluminosilicate glass matrix. Pyrrhotite and wurtzite-sphalerite are sulfide species containing Fe and Zn, but an important fraction of iron is also present in the aluminosilicate glass. These clear differences between the speciation of the above elements in this material and those reported for fly ash from conventional PC combustion.

  13. Environmental impact of the use of fly ash and FGD residues in earthworks. Research notes

    SciTech Connect

    Eskola, P.; Mroueh, U.M.

    1998-12-31

    The goal of this project was to assess the environmental impact of using fly ash and flue gas desulfurization (FGD) residues (produced by pulverized coal-fired power plants which employ semi dry scrubbing technology) in earthworks. The use of fly ash and FGD residues was compared with the use of natural minerals (sand, gravel and macadam) in road construction and clay stabilization. The assessment includes the following environmental effects caused by extraction, production and transportation of raw materials and the road construction process: energy and fuel consumption, consumption of raw materials, emissions into air, leaching of impurities, noise, dust emissions, land use and accident risks. The environmental impacts were assessed for a 1 km long road over a period of 50 years.

  14. 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.

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

    PubMed

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

    2013-03-01

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

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Effects of different treatments of fly ash and mining soil on growth and antioxidant protection of Indian wild rice.

    PubMed

    Bisoi, Sidhanta Sekhar; Mishra, Swati S; Barik, Jijnasa; Panda, Debabrata

    2017-05-04

    The aim of the present study was investigation of the effects of fly ash and mining soil on growth and antioxidant protection of two cultivars of Indian wild rice (Oryza nivara and Oryza rufipogon) for possible phytoremediation and restoration of metal-contaminated site. In this study, Indian wild rice showed significant changes in germination, growth, and biochemical parameters after exposure to different ratio of fly ash and mining soil with garden soil. There was significant reduction of germination, fresh weight, dry weight, leaf chlorophyll content, leaf area, Special Analysis Device Chlorophyll (SPAD) Index, proteins, and activities of antioxidant enzymes in both cultivars of the wild rice grown in 100% fly ash and mining soil compared to the plants grown in 100% garden soil. Results from this study showed that in both cultivars of wild rice, all growth and antioxidant parameters increased when grown in 50% fly ash and mining soil. Taken together, Indian wild rice has the capacity to tolerate 50% of fly ash and mining soil, and can be considered as a good candidate for possible phytoremediation of contaminated soils.

  3. Roller compacted base course construction using lime stabilized fly ash and flue gas desulfurization sludge by-product

    SciTech Connect

    Beeghly, J.J.

    1996-10-01

    Dewatered calcium sulfite and calcium sulfate sludges from flue gas desulfurization (FGD) processes at coal fired power plants can be mixed with coal fly ash and lime to cause a cementitious chemical reaction used to construct a roller compacted base course or an impermeable pond liner. Tile chemical reaction is often shown as lime reacting with alumina from the fly ash which in turn reacts with the calcium sulfite and sulfate FGD waste to form sulfo-aluminate. Better understanding is needed of the controlling factors that result in a successful application of this chemical reaction which has been linked to past construction failures due to latent hydration causing expansion damage or degradation of concrete, called sulfate attack. Factors such as optimum moisture content, fly ash to FGD ratio, and age of FGD are examined that affect strength gain and freeze-thaw durability. Several recently completed field demonstrations are discussed.

  4. The fly ash influenced the heavy metal status of the soil and the seeds of sunflower. A case study.

    PubMed

    Siddiqui, Shazia; Ahmad, A; Hayat, S

    2004-01-01

    In this study, four cultivars of sunflower (Helianthus annuus) were grown in the sandy loam soil, supplemented with graded (v/v) quantity (0, 20, 40, 60, 80, 100%) of the fly ash, released by the combustion of the coal from the thermal power plant. The presence of fly ash in the soil increased its porosity, water holding capacity, pH, E.C., C.E.C., the content of sulphate, carbonate, bicarbonate, chloride, phosphorus, potassium, calcium and various trace elements. However, in the seeds, except Fe, Pb, Mn and Zn, and other heavy metals remained untraced up to 40% of the fly ash, above that their quantity slightly increased but the values are very much under the permissible limits.

  5. The influence of nickel slag aggregate concentration to compressive and flexural strength on fly ash-based geopolymer composite

    NASA Astrophysics Data System (ADS)

    Sujiono, E. H.; Setiawan, A.; Husain, H.; Irhamsyah, A.; Samnur, S.; Subaer, S.

    2016-04-01

    Fly ash-based geopolymer with nickel slag aggregate has been successfully produced. Fly ash and nickel slag were obtained from Bosowa Jeneponto Power Plant and PT. Vale Indonesia, respectively. This research aims to investigate the influence of nickel slag concentration to compressive strength, flexural strength, and microstructure of geopolymer composite. The increment of nickel slag aggregate on fly ash was relative to the weight of samples. Geopolymer composite were synthesized by using alkali activated method, cured at temperature of 70 °C for 1 hour. The resulting composites were left at room temperature for 14 days, before compressive and flexural strength were performed. The results showed that the addition of nickel slag aggregate was found to increase the compressive strength of the material. The optimum compressive strength was 14.81 MPa with the addition of 10% aggregate. The optimum flexural strength was 2.63 MPa with the addition of 15% aggregate.

  6. 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.

  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. 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.

  9. Adsorption of Chrysoidine R by using fly ash in batch process.

    PubMed

    Matheswaran, Manickam; Karunanithi, Thirugnanam

    2007-06-25

    This investigation deals with effective utilization of fly ash as adsorbent for the removal of Chrysoidine R from the aqueous solution. The fly ash is a major byproduct generated in coal-based thermal power plants and has good potential for use as an adsorbent. A series of experiments were carried out in a batch adsorption technique to obtain the effect of process variables viz. contact time, pH (2, 4, 6 and 8) initial concentration of the dye (400, 600, 800 and 1000mgL(-1)), amount of the adsorbent (125, 250, 375 and 500mgL(-1)), and temperature (303, 313, 323 and 333K) on adsorption. The concentration of dye was determined by spectrophotometer. The results showed that as the amount of the adsorbent was increased, the percentage of dye removal increased accordingly; higher adsorption percentage was observed at lower concentration of chrysoidine. The adsorption data were analyzed using Langmuir and Freundlich isotherms. The adsorption was found to obey pseudo-first order kinetics. An intra particle diffusion model was used to fit the experimental data. The thermodynamic parameters such as standard change in free energy, enthalpy and entropy of adsorption have been calculated. Adsorption of Chrysoidine R on fly ash was found to be an exothermic reaction.

  10. Fly ash from a Mexican mineral coal I: Mineralogical and chemical characterization.

    PubMed

    Medina, Adriana; Gamero, Prócoro; Querol, Xavier; Moreno, Natalia; De León, Beatriz; Almanza, Manuel; Vargas, Gregorio; Izquierdo, María; Font, Oriol

    2010-09-15

    The properties of coal fly ash are strongly dependent on the geological origin and the combustion process of the coal. It is important to characterize regional fly ash in detail to ascertain its potential uses as raw material in the production of high value products. The physicochemical properties of fly ash coming from the "Jose Lopez Portillo" coal-fired power plant, Coahuila, Mexico (MFA), are presented in this work. A detailed study of trace elements, the chemical composition of the amorphous phase, thermal stability and the leaching of contaminant elements under different conditions are included. MFA is composed of mullite, quartz, calcite, magnetite and an amorphous phase. This material contains mainly silica (59.6%), alumina (22.8%) and magnetite (5.6%). Its amorphous phase (78.3%) has a high silica (49.4%) and alumina (14.4%) content. According to its mineralogical and chemical composition, MFA is potentially useful as a raw material for making cement, silica, and alumina, as well as low silica/alumina ratio zeolites. Deleterious elements could be removed during the zeolitization process or with an additional acid treatment. Because of its morphological properties and structural and thermal stability, MFA can be used in thermal isolation and refractory materials and as a support for heterogeneous catalysts.

  11. Enrichment and oral bioaccessibility of selected trace elements in fly ash-derived magnetic components.

    PubMed

    Bourliva, Anna; Papadopoulou, Lambrini; Aidona, Elina; Simeonidis, Konstantinos; Vourlias, George; Devlin, Eamonn; Sanakis, Yiannis

    2016-11-04

    The mineralogy, morphology, and chemical composition of magnetic fractions separated from fly ashes (FAs) originating from Greek lignite-burning power plants was investigated. The oral bioaccessibility of potentially harmful elements (PHEs) from the fly ash magnetic fractions (FAMFs) was also assessed using in vitro gastrointestinal extraction (BARGE Unified Bioaccessibility Method, UBM). The FAMFs isolated were in the range 4.6-18.4%, and their mass specific magnetic susceptibility ranged from 1138 × 10(-8) to 1682 × 10(-8) m(3)/kg. XRD analysis and Mossbauer spectroscopy indicated that the dominant iron species were Fe-rich aluminosilicate glass along with magnetite, hematite, and maghemite (in decreasing order). The raw FAs exhibited differences in their chemical composition, indicating the particularity of every lignite basin. The elemental contents of FAMFs presented trends with fly ash type; thus, the FAMFs of high-Ca FAs were enriched in siderophile (Cr, Co, Ni) and lithophile (Cs, Li, Rb) elements and those separated from low-Ca FAs were presented depleted in chalcophile elements. Based on UBM extraction tests, the PHEs were more bioaccessible from the non-magnetic components of the FAs compared to the magnetic ones; however, the bioaccessible fractions estimated for the FAMFs were exceeding 40 % in many cases. Arsenic was found to be significantly bioaccessible (median ~ 80 %) from FAMFs despite the lower As contents in the magnetic fraction.

  12. Investigation of sewage sludge stabilization potential by the addition of fly ash and lime.

    PubMed

    Samaras, P; Papadimitriou, C A; Haritou, I; Zouboulis, A I

    2008-06-15

    The aim of this work was the examination of stabilization potential of sewage sludge by the addition of fly ash and/or lime and the investigation of the effect of stabilization time on the properties of produced mixtures. Five samples were prepared by mixing fly ash, sewage sludge and lime in various ratios and the mixtures were stabilized for a period of 35 d. The addition of alkaline agents resulted in the increase of sample pH up to 12, the increase of total solids content to about 50% and the reduction of the organic fraction of the solids. The produced samples presented inhibition effects to seed germination and root length growth of three higher plants (one monocotyl and two dicotyls); however, samples with high sludge content resulted in negligible seed germination inhibition at prolonged stabilization times. The standard TCLP leaching procedure was applied in all the produced samples in order to evaluate the extraction potential of certain metallic elements; the content of metals in the eluates was varied, depending upon their speciation and form. Eluates presented significant inhibition to the marine photobacterium Vibrio fischeri bioluminescence, while the lowest inhibition was detected for the samples containing higher sludge content. These samples potentially could be applied as soil amendment, offering an efficient method for the combined utilization of two different solid wastes; however, low dosages of fly ash should be used for the production of a stabilized material presenting negligible effects with respect to its phytotoxic and ecotoxic properties.

  13. Fly ash utilization in McLean County, North Dakota. Topical report, Task 7.25

    SciTech Connect

    Moretti, C.J.

    1993-03-01

    In 1989, the McLean County Commissioners requested assistance from personnel at the University of North Dakota Energy and Environmental Research Center (EERC) with the construction of a section of road and a boat ramp in their county. Assistance was sought from the EERC because the county`s construction plans called for partial replacement of the lime and portland cement normally used for soil stabilization with fly ash. Since the EERC had recently conducted several research projects dealing with the use of coal combustion by-products for road construction, the commissioners requested that EERC personnel help to determine appropriate formulas for the stabilized soil mixtures to be used for both the road and boat ramp applications. An additional incentive was provided when the management of the Coal Creek Power Plant offered to donate the necessary fly ash at no cost. This project was performed as a joint venture between McLean County and the EERC. The EERC was primarily responsible for conducting a laboratory testing program to develop soil stabilization mixtures for the two construction activities. These mixtures were to contain a relatively high percentage of fly ash and to exhibit sufficient strength and durability so that the road and boat ramp would both have a service life of 20 years or more. McLean County would be primarily responsible for the road and boat ramp construction activities. The funding for the EERC portion of the project was provided by the US Department of Energy through a joint venture support program.

  14. Alkali-activated concrete with Serbian fly ash and its radiological impact.

    PubMed

    Nuccetelli, Cristina; Trevisi, Rosabianca; Ignjatović, Ivan; Dragaš, Jelena

    2017-03-01

    The present paper reports the results of a study on different types of fly ash from Serbian coal burning power plants and their potential use as a binder in alkali-activated concrete (AAC) depending on their radiological and mechanical properties. Five AAC mixtures with different types of coal burning fly ash and one type of blast furnace slag were designed. Measurements of the activity concentrations of (40)K, (226)Ra and (232)Th were done both on concrete constituents (fly ash, blast furnace slag and aggregate) and on the five solid AAC samples. Experimental results were compared by using the activity concentration assessment tool for building materials - the activity concentration index I, as introduced by the EU Basic Safety Standards (CE, 2014). All five designed alkali-activated concretes comply with EU BSS screening requirements for indoor building materials. Finally, index I values were compared with the results of the application of a more accurate index - I(ρd), which accounts for thickness and density of building materials (Nuccetelli et al., 2015a). Considering the actual density and thickness of each concrete sample index - I(ρd) values are lower than index I values. As an appendix, a synthesis of main results concerning mechanical and chemical properties is provided.

  15. 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

  16. Investigation of unburned carbon particles in fly ash by means of laser light scattering

    NASA Astrophysics Data System (ADS)

    Iannone, R. Q.; Morlacchi, R.; Calabria, R.; Massoli, P.

    2011-02-01

    A new optical method to determine the percentage of unburned carbon particles in fly ash from combustion of pulverized coal has been developed. The technique exploits the different properties of particles of ash and coal in the elastic scattering of polarized light. The polarization measurements were performed using a linearly polarized laser source and a receiving system able to simultaneously detect the scattered radiation polarized in parallel and orthogonal planes, under the scattering angle of 60°. The parallel and perpendicular components of the scattered light intensities are measured in order to determine the polarization ratio. The operation of the system was tested under various conditions using monodisperse glass spheres. The performance of the novel device was assessed in several sets of measurements with samples of fly ash produced from coal fired power plants. A correlation between the relative content of coal and ashes and the polarization ratio of scattered light was demonstrated. The resulting polarization ratio showed values ranging from 1.25 to 0.94 for a carbon content of 1.17 wt% and 16.3 wt%, respectively. The uncertainty on the measured percentage of unburned carbon was about 1%. The proposed device represents an attractive tool for monitoring real-time burnout and combustion efficiency.

  17. 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.

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

    SciTech Connect

    Yongchun Zhao; Junying Zhang; Junmin Sun; Xiangfei Bai; Chuguang Zheng

    2006-08-15

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

  19. Fetal translocation and metabolism of PAH obtained from coal fly ash given intratracheally to pregnant rats

    SciTech Connect

    Srivastava, V.K.; Chauhan, S.S.; Srivastava, P.K.; Kumar, V.; Misra, U.K.

    1986-01-01

    Polycyclic aromatic hydrocarbons (PAH) were extracted from coal fly ash collected from the electrostatic precipitator of a thermal power plant. The PAH extract was given intratracheally daily to pregnant rats (2 mg/100 g body weight) on d 18 and 19 of gestation. In addition of d 19 of gestation rats were also given (/sup 4/H)benzo(a)pyrene intratracheally. Rats were sacrificed on d 20 of gestation, and the distribution of (/sup 3/H)benzo(a)pyrene radioactivity and PAH of coal fly ash was studied in maternal lung, liver, and placenta, as well as in the liver and lung of the fetus. The radioactivity of intratracheally given benzo(a)pyrene was found in liver (68%), placenta (4%), fetal lung (1.9%), and fetal liver (1.4%) of maternal lung. Intratracheally administered PAH of coal fly ash were translocated to maternal liver and placenta, as well as to the liver and lung of the fetus. PAH of coal fly ash were also metabolized to several minor and major metabolites by maternal lung, liver, and placenta, as well as by the maternal fetal liver and lung. Some of the PAH metabolites in lung and liver were common; however, the major metabolite of liver, M-16, was different from the major metabolite M-16 of lung. The major PAH metabolite of placenta, M-15, and fetal liver, F-12, were common PAH metabolites. M-2 and M-6 of the placenta and F-5 and F-10 of the fetal lung were also common.

  20. Use of recycled glass and fly ash for precast concrete. Final report

    SciTech Connect

    Meyer, C.; Baxter, S.

    1998-10-01

    An 18-month research project was conducted to study the technical and economic feasibility of using crushed waste glass and chemically self-activated fly ash, a byproduct of coal-burning power plants, to produce precast concrete products. The crushed glass is used as substitute for the aggregate, and the fly ash is substituted for Portland cement as binder. Technically, the important problem of alkali-silica reaction (ASR) had to be addressed and was partially solved in a separate research program funded by NYSERDA. In the present project, additional knowledge was obtained about this important phenomenon, especially in cases where the glass is sorted by color, larger aggregate sizes are desirable, and glass constitutes up to 100% of the aggregate. The primary goal of this research was to develop a material with a particularly attractive appearance that would be suitable for architectural and decorative applications. The use of this material, tentatively called `glascrete`, has been shown to be technically and economically feasible to the point that it is ready for commercial exploitation, provided regular portland cement is used as the binder. Extensive efforts have been made, in conjunction with a project supported by the New York State Department of Economic Development, to spur private parties to product glascrete products commercially. The use of chemically self-activated fly ash as cement replacement is technically feasible by not yet commercially viable. Efforts to search for less costly chemical activators are continuing. If these efforts are successful, the end result could be a material that consists almost entirely of recycled components namely crush waste glass and fly ash.

  1. Application of fly ash on the growth performance and translocation of toxic heavy metals within Cajanus cajan L.: implication for safe utilization of fly ash for agricultural production.

    PubMed

    Pandey, Vimal Chandra; Abhilash, P C; Upadhyay, Raj Narayan; Tewari, D D

    2009-07-15

    The present study was undertaken to examine the influence of the application of fly ash (FA) into garden soil for Cajanus cajan L. cultivation and on accumulation and translocation of hazardous metals from FA to edible part. Numerous studies have been reported on the growth and yield of agricultural crops under FA stress; however, there is a dearth of studies recommending the safe utilization of fly ash for crop production. Pot experiments were conducted on C. cajan L., a widely cultivating legume in India for its highly nutritious seeds. C. cajan L. were grown in garden soil and amended with varying concentrations of FA in a weight/weight ratio (0%, 25%, 50% and 100%; w/w). Incorporation of fly ash from 25% to 100% in garden soil increases the levels of pH, particle density, porosity and water holding capacity from 3.47% to 26.39%, 3.98% to 26.14%, 37.50% to 147.92% and 163.16% to 318.42%, respectively, than the control while bulk density decrease respectively from 8.94% to 48.89%. Pot experiment found that accumulation and translocation of heavy metals in tested plant depends on the concentration of FA. Addition of FA at lower concentration (25%) had shown positive results in most of the studied parameters of growth and yield (14.23% than control). The experimental results confirmed that lower concentration of FA (25%) is safe for C. cajan cultivation, which not only enhanced the yield of C. cajan L. significantly but also ensured the translocation of heavy metals to edible parts within the critical limits.

  2. 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

  3. Advanced research and technology: direct utilization-recovery of minerals from coal fly ash. Technical progress report, 1 October 1978-30 September 1979

    SciTech Connect

    Burnet, G.; Murtha, M.

    1980-01-01

    Research focused on technical development of promising methods for recovering minerals from power plant fly ash. Development of the high-temperature (HiChlor) gas chlorination process and refinement and definition of the recovery steps of extraction and desilication for the lime-soda sinter process were emphasized. A preliminary design and cost estimate for commercialization of the HiChlor process and a proposal for a process development unit for scale-up of the lime-soda sinter process were prepared. Both physical and chemical beneficiation techniques to upgrade the iron content of the magnetic fly ash were tested; chemical beneficiation using high-temperature NaOH leaching was found to be the most effective method. Pretreatment for each of the processes includes magnetic separation of coal fly ash. Bituminous coal fly ashes contain magnetic iron oxide particles which can be removed by magnetic separation. The magnetic material consists primarily of iron oxides, with small amounts of silica and alumina. Removal of additional silica and alumina will give a product which can be used for steel production. Physical investigations included careful study of internal structure of fly ash particles. Fly ash samples were separated for a range of electromagnetic power settings and the fractions were analyzed for size determinations, chemical compositions, and morphological contents. Chemical analyses showed that, for the nonmagnetic fly ash fractions, the silica and iron contents are independent of size, and that the alumina content is highest in the smaller particles.

  4. Wood pellet fly ash and bottom ash as an effective liming agent and nutrient source for rye grass (Lolium perenne L.) and oats (Avena sativa).

    PubMed

    Park, Nathan D; Michael Rutherford, P; Thring, Ronald W; Helle, Steve S

    2012-01-01

    Fly ash (FA) and bottom ash (BA) from a softwood pellet boiler were characterized and evaluated as soil amendments. In a greenhouse study, two plant species (rye grass, Lolium perenne L. and oats, Avena sativa) were grown in three different treatments (1% FA, 1% BA, non-amended control) of a silty loam soil. Total concentrations of plant nutrients Ca, K, Mg, P and Zn in both ashes were elevated compared to conventional wood ash. Concentrations of Cd, Cr, Pb, Se and Zn were found to be elevated in the FA relative to BA and the non-amended soil. At 28 d, oat above-ground biomass was found to be significantly greater in soil amended with FA. Potassium and Mo plant tissue concentrations were significantly increased by addition of either ash, and FA significantly increased Zn tissue concentrations. Cadmium and Hg tissue concentrations were elevated in some cases. As soil amendments, either pellet ash is an effective liming agent and nutrient source, but high concentrations of Cd and Zn in FA may preclude its use as an agricultural soil amendment in some jurisdictions. Lower ash application rates than those used in this study (i.e. <1%) may still provide sufficient nutrients and effective neutralization of soil acidity.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Kinetics and equilibrium of adsorption of dissolved organic matter fractions from secondary effluent by fly ash.

    PubMed

    Wei, Liangliang; Wang, Kun; Zhao, Qingliang; Xie, Chunmei; Qiu, Wei; Jia, Ting

    2011-01-01

    Fly ash was used as a low-cost adsorbent for removing dissolved organic matter (DOM) in secondary effluent. Batch experiments were conducted under various adsorbent dosages, pH, contact time, temperatures and DOM fractional characteristics. Under the optimum conditions of fly ash dosage of 15 g/L, temperature of 303 K and contact time of 180 min, a removal of 22.5% of the dissolved organic carbon (DOC), 23.7% of UV-254, 25.9% of the trihalomethanes precursors in secondary effluent was obtained. The adsorption of DOM fractions onto fly ash all followed the pseudo second-order kinetic model, and the hydrophilic fraction adsorption by fly ash also fitted the intraparticle diffusion model quite well. Freundlich and Langmuir models were applicable to the fly ash adsorption and their constants were evaluated. The maximum adsorption capacities of the adsorptions revealed that fly ash was more effective in adsorbing hydrophilic fraction than the acidic fractions. Structure changes of the DOM fractions after fly ash adsorption were also characterized via spectrum analyzing. Those mechanisms presented critical step toward improved efficiencies of fly ash adsorption via further surface-modification.

  13. 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...

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  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. Bonded Fly Ash: A Low-Energy Replacement for Portland Cement Concrete to Improve Resistance to Chem-Bio Intrusion

    DTIC Science & Technology

    2002-10-01

    The paper discusses the background of cementitious materials, and generally compares natural (Pozzolanic) cement to manufactured ( Portland ) cement . Fly...ash is discussed as a common Pozzolan, and in particular, the low-energy requirement for fly ash as compared to Portland cement . Also...photomicrographs of fly ash particles and of chemically bonded fly ash are compared to a photomicrograph of Portland cement particles and a photograph of Portland

  8. Development of fly ash-based slope protection materials for waste disposal ponds. Topical report, Task 7.7

    SciTech Connect

    Moretti, C.J.

    1993-02-01

    A research project was conducted to develop a cost-effective slope protection material for a 100-acre scrubber sludge disposal pond located at the Sherco power plant. The technical objective of the project was to formulate and evaluate the performance of a slope protection material produced using self-cementing coal combustion by-products. The material was to have sufficient durability and erosion resistance to protect the underlying bottom ash fill and clay liner from wave erosion for at least 5 years when it was placed on the interior side slopes of the pond. The two coal combustion by-products that were considered for use in the slope protection material were 1) a spray dryer waste and 2) a subbituminous coal fly ash. The spray dryer waste was approximately a 50:50 mixture of subbituminous coal fly ash and reacted, lime-based scrubber sorbent. The subbituminous coal fly ash was produced from a cyclone-fired boiler. Both by-products displayed self-cementing behavior when mixed with water. The results of the field tests indicated that a slope protection slab prepared from Sherco spray dryer waste placed with a 20% moisture content showed almost no deterioration after 20 months in the field. A slab prepared from a mixture of 25% Riverside fly ash and 75% bottom ash with a moisture content of 18% showed a slight loss of material from the surface of the slab, but no substantial deterioration after 20 months in the field. Two other materials containing Riverside fly ash that were prepared with higher moisture contents showed somewhat more deterioration after 20 months, although none of the field test slabs appeared to have failed in that time period.

  9. 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.

  10. 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.

  11. 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.

  12. Bioaccumulation Studies Associated with the Kingston Fly Ash Spill, Spring 2009 - Fall 2010

    SciTech Connect

    Adams, Marshall; Brandt, Craig C; Fortner, Allison M

    2012-05-01

    In December 2008, an ash dike at the Tennessee Valley Authority (TVA) Kingston Fossil Plant ruptured, releasing over one billion gallons of coal fly ash into the Emory and Clinch Rivers. Coal fly ash may contain several contaminants of concern, but of these selenium (Se) and arsenic (As) have been highlighted because of their toxicity and tendency to bioaccumulate in aquatic food chains. To assess the potential impact of the spilled fly ash on humans and the environment, a comprehensive biological and environmental monitoring program was established, for which resident aquatic organisms (among other sample media) are collected to determine contaminant exposure and evaluate the risk to humans and wildlife. Studies on bioaccumulation and fish health are major components of the TVA Biological Monitoring Program for the Kingston fly ash project. These studies were initiated in early Spring 2009 for the purposes of: (1) documenting the levels of fly ash-associated metals in various tissues of representative sentinel fish species in the area of the fly ash spill, (2) determining if exposure to fly ash-associated metals causes short, intermediate, or long-term health effects on these sentinel fish species, (3) assessing if there are causal relationships between exposure (to metals) and effects on fish, (4) evaluating, along with information regarding other ecological and physicochemical studies, the nature and route of contaminant transfer though food chains into higher level consumers, (5) providing important information for the Ecological Risk Assessment (ERA) for the Kingston fly ash project, and (6) serving as an important technology transfer or model study focused on how to best evaluate the environmental effects of fly ash, not only at the Kingston site, but also at sites on other aquatic systems where coal-fired generating stations are located. This report summarizes the bioaccumulation results from the first two years of study after the fly ash spill, including

  13. 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.

  14. Dynamics of Anthropogenic Ferrimagnetics (fly-Ashes) in Soils - Experiments on Test Fields

    NASA Astrophysics Data System (ADS)

    Kapicka, A.; Petrovsky, E.; Fialova, H.; Kodesova, R.

    2007-12-01

    Magnetic properties of recent soils are often studied with the aim to asses the level of contamination due to atmospheric deposition of pollutants. In order to interpret properly magnetic data, several factors have to be taken into account. Lithogenic effect on top soil magnetic properties, pedogenic processes in soils, magnetic stability of anthropogenic ferrimagnetics in real soil conditions have been discussed in earlier studies. The other limiting effect, quite omitted in the past, is possible migration of anthropogenic farrimagnetics in vertical soil profiles. In our contribution we report on experimental investigation of temporal variation of power-plant fly ashes under different soil properties (soil, grass, sand), as well as different land morphology. In experiments on test fields we used fly ashes from two coal-burning power plants, showing relatively narrow grain-size distribution, with the mean of 10.5 Ým. Magnetite and/or maghemite was identified as dominant ferromagnetic phase. Temporal variations of vertical distribution of magnetic susceptibility along soil columns, with surface artificially contaminated by the power-plant fly ashes, were investigated using MAGPROX SM400 susceptibility meter. Our preliminary results, covering a period of more than one year, indicate that vertical distribution of particles in topsoil layers is in the investigated cases relatively stable. Vertical migration of deposited particles is practically buffered in the top 1-2 cm, and surface magnetic susceptibility was not distinctly modified. On the other hand, surface dynamics of anthropogenic ferrimagnetics may be radically affected by water regime (precipitation) especially during the winter period. This resaerch was carried out within GA AVCR Project No IAA300120701.

  15. 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.

  16. [Characterization of PAHs in fly ashes from coke production].

    PubMed

    Mu, Ling; Peng, Lin; Liu, Xiao-Feng; Bai, Hui-Ling; Zhang, Jian-Qiang

    2013-03-01

    In order to investigate the characteristics of polycyclic aromatic hydrocarbons (PAHs) in ashes from coking, PAHs in ashes from three coke production plants were analyzed with GC-MS, and the distribution characteristics of PAHs and potential toxicity risk were discussed. The sum of 16 EPA prior PAHs varied from 8.17 x 10(2) to 5.17 x 10(3) microg x g(-1). PAH contents from the coke oven (stamp charging) with the height of 3.2 m were two times higher than those from the one (top charging) with the height of 6.0 m, and PAHs in ashes from coal charging were significantly higher than those from coke pushing in the same plant. Four-ring and five-ring PAHs were the dominant species in ashes from coking and the sum of them accounted for more than 80.00% of total PAHs. Chrysene (Chr), benzo [a] anthracene (BaA) and benzo [b] fluoranthene (BbF) were abundant in all ash samples. The content of total BaP-based toxic equivalency (BaPeq) ranged from 1.64 x 10(2) to 9.57 x 10(2) microg x g(-1). From the carcinogenic point of view, besides benzo [a] pyrene (BaP), dibenz [a,h] anthracene (DbA) contributed most to the overall toxicity of PAHs, followed by BaA and BbF. BaPeq concentration from coal charging was 5.21-fold higher than that from coke pushing, indicating that different reuse ways should be considered based on their specific toxicity profiles of PAHs.

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

    SciTech Connect

    Ward, C.K.; Mendonca, M.T.

    2006-08-15

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

  18. 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

  19. 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.

  20. 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.

  1. A STUDY OF THE EFFECTS OF POST-COMBUSTION AMMONIA INJECTION ON FLY ASH QUALITY: CHARACTERIZATION OF AMMONIA RELEASE FROM CONCRETE AND MORTARS CONTAINING FLY ASH AS A POZZOLANIC ADMIXTURE

    SciTech Connect

    Robert F. Rathbone; Thomas L. Robl

    2001-04-11

    Work completed in this reporting period focused on finalization of the Work and Management Plan, sample acquisition and analysis, evaluation of ammonia measurement methods, and measurement of ammonia loss from mortar. All fly ash samples have been acquired and analyzed for chemical composition and particle fineness. Three non-ammoniated fly ash samples were obtained from power plants that do not inject ammonia for NOx or particulate control, while three ammoniated fly ashes originate from plants that inject ammonia into the flue gas. The fly ash sources were selected based on their marketability as concrete admixtures and ammonia content. Coarse and fine aggregates for mortar and concrete testing have also been secured and have been thoroughly characterized using ASTM methods. Methodologies for the measurement of ammonia in the gaseous and aqueous phase have been carefully considered in the context of their suitability for use in this project. These include ammonia detection tubes, carbon impregnated with sulfuric acid (CISA) tubes, titration, and electrochemical methods. It was concluded that each of these methods is potentially useful for different aspects of the project, depending on the phase and concentration of ammonia to be measured. Preparation of fly ash-containing mortars both with and without ammonia indicated that the ammonia has no significant influence on compressive strength. Finally, measurement of ammonia loss from mortar has begun and the results of several of these experiments are included herein. It has been found that, under the laboratory curing conditions devised, ammonia release from mortar occurs at a relatively rapid rate in the first 24 hours, proceeded by a much slower, essentially linear rate. Furthermore, at the end of the three-week experiments, it was calculated that greater than 80% of the initial ammonia concentration remained within the mortar.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. [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.

  9. Improving the mechanical characteristics and restraining heavy metal evaporation from sintered municipal solid waste incinerator fly ash by wet milling.

    PubMed

    Sun, Chang-Jung; Li, Ming-Guo; Gau, Sue-Huai; Wang, Ya-Hui; Jan, Yi-Lin

    2011-11-15

    The milling process has a verified stabilizing effect on the leaching of heavy metals into the environment from municipal solid waste incinerator (MSWI) fly ash. The aim of this current study is to further improve and confirm the effectiveness of the process by exploring its effects on the evaporation of heavy metals and on the mechanical characteristics of the sintered MSWI fly ash. The chemical composition of the MSWI fly ash is first altered by the addition of water treatment plant sludge (WTS) and cullet, and then processed to produce sintered specimens suitable for reuse as an aggregate. In the experiments, fly ash, WTS and cullet (40%: 30%: 30%, respectively) were mixed and milled for 1h. Samples were sintered for 60 min at temperatures of 850, 900, 950 and 1000°C. Test results confirm that milling increased the compressive strength of the sintered specimens. The compressive strength of unmilled specimens sintered at 900°C was only 90 kg/cm(2), but that of milled specimens was 298 kg/cm(2) when sintered at only 850°C. There was also an improvement in the soundness ranging from 11.04% to 0.02% and a reduction in the evaporation rates of Pb, Cd, Cu, Cr and Zn from 54-64%, 43-49%, 38-43%, 30-40% and 14-35% (900-1000°C) to 19-21%, 19-21%, 14-19%, 12-19% and 14-17% (850-1000°C), respectively. The improvement in compressive strength was attained by the combination in the liquid sintering stage of powdered ash with the amorphous material. The amorphousness of the material also helped to seal the surface of the fly ash, thereby reducing the evaporation of heavy metals during the heating process.

  10. The occurrence of quartz in coal fly ash particles

    SciTech Connect

    Meij R.; Nagengast S.; Winkel H.T.

    2000-10-15

    Quartz is present in both coal and residual ash. Ash originates from combustion of pulverised coal and, once removed from the flue gases by electrostatic precipitators (ESPs), it is called pulverized fuel ash (PFA). Thus, occupational exposure to PFA could also include exposure to silica. However, epidemiological studies did not show evidence of progressive massive fibrosis (PMF). In vitro tests demonstrated that PFA is less toxic than silica, and in vivo data of PFA did not support the importance of silica content for toxicity. Commissioned by the Dutch coal-fired power plants, KEMA has started a research project to determine the quartz content in coal and the corresponding PFA. It appears that on average 50% of the alpha-quartz in coal is found again in the total fraction of PFA (D50(ae) 31 {mu}m, where D50(ae) is the aerodynamically mass median diameter), whereas 16% is found in an even finer fraction (D50(ae) 10 {mu}m). The remaining part of the quartz is embedded in a glass phase. Scanning electron microscopy (SEM) with x-ray microanalyses (XMA) of cross-sections of 11,130 ash particles showed that quartz in PFAis present as unmelted sand particles. These quartz particles are angularly shaped. However, two types are to be distinguished: free coarse angular quartz particles (not respirable) and small angular quartz particles within the PFA particles. From the SEM/XMA results, it has to be concluded that the quartz in the respirable fraction is predominantly present within the original molten PFA particle. Since the effects of quartz are surface related, this elucidates the negative results of quartz-related effects of PFA in epidemiological, in vitro and in vivo studies. Besides, the amount of the total alpha-quartz in the respirable fraction of the ashes studied is less than 0.2%, so probably the Dutch occupational quartz standard of 0.075 mg m{sup 3} will not be exceeded.

  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. 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.

  13. 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.

  14. 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.

  15. 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

  16. Progression in sulfur isotopic compositions from coal to fly ash: Examples from single-source combustion in Indiana

    USGS Publications Warehouse

    Yaofa, Jiang; Elswick, E.R.; Mastalerz, Maria

    2008-01-01

    Sulfur occurs in multiple mineral forms in coals, and its fate in coal combustion is still not well understood. The sulfur isotopic composition of coal from two coal mines in Indiana and fly ash from two power plants that use these coals were studied using geological and geochemical methods. The two coal beds are Middle Pennsylvanian in age; one seam is the low-sulfur ( 5%) Springfield Coal Member of the Petersburg Formation. Both seams have ash contents of approximately 11%. Fly-ash samples were collected at various points in the ash-collection system in the two plants. The results show notable difference in ??34S for sulfur species within and between the low-sulfur and high-sulfur coal. The ??34S values for all sulfur species are exclusively positive in the low-sulfur Danville coal, whereas the ??34S values for sulfate, pyritic, and organic sulfur are both positive and negative in the high-sulfur Springfield coal. Each coal exhibits a distinct pattern of stratigraphic variation in sulfur isotopic composition. Overall, the ??34S for sulfur species values increase up the section in the low-sulfur Danville coal, whereas they show a decrease up the vertical section in the high-sulfur Springfield coal. Based on the evolution of ??34S for sulfur species, it is suggested that there was influence of seawater on peat swamp, with two marine incursions occurring during peat accumulation of the high-sulfur Springfield coal. Therefore, bacterial sulfate reduction played a key role in converting sulfate into hydrogen sulfide, sulfide minerals, and elemental sulfur. The differences in ??34S between sulfate sulfur and pyritic sulfur is very small between individual benches of both coals, implying that some oxidation occurred during deposition or postdeposition. The ??34S values for fly ash from the high-sulfur Springfield coal (averaging 9.7???) are greatly enriched in 34S relative to those in the parent coal (averaging 2.2???). This indicates a fractionation of sulfur isotopes

  17. Optimization of hydrothermal synthesis of pure phase zeolite Na-P1 from South African coal fly ashes.

    PubMed

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

    2012-01-01

    This study was aimed at optimizing the synthesis conditions for pure phase zeolite Na-P1 from three coal fly ashes obtained from power stations in the Mpumalanga province of South Africa. Synthesis variables evaluated were: hydrothermal treatment time (12-48 hours), temperature (100-160°C) and varying molar quantities of water during the hydrothermal treatment step (H(2)O:SiO(2) molar ratio ranged between 0-0.49). The optimum synthesis conditions for preparing pure phase zeolite Na-P1 were achieved when the molar regime was 1 SiO(2): 0.36 Al(2)O(3): 0.59 NaOH: 0.49 H(2)O and ageing was done at 47°C for 48 hours. The optimum hydrothermal treatment time and temperature was 48 hours and 140°C, respectively. Fly ashes sourced from two coal-fired power plants (A, B) were found to produce nearly same high purity zeolite Na-P1 under identical conditions whereas the third fly ash (C) lead to a low quality zeolite Na-P1 under these conditions. The cation exchange capacity for the high pure phase was found to be 4.11 meq/g. These results highlight the fact that adjustment of reactant composition and presynthesis or synthesis parameters, improved quality of zeolite Na-P1 can be achieved and hence an improved potential for application of zeolites prepared from coal fly ash.

  18. Optimal boiler control through real-time monitoring of unburned carbon in fly ash by laser-induced breakdown spectroscopy

    NASA Astrophysics Data System (ADS)

    Kurihara, Miki; Ikeda, Koji; Izawa, Yoshinori; Deguchi, Yoshihiro; Tarui, Hitoshi

    2003-10-01

    A laser-induced breakdown spectroscopy (LIBS) technique has been applied for detection of unburned carbon in fly ash, and an automated LIBS unit has been developed and applied in a 1000-MW pulverized-coal-fired power plant for real-time measurement, specifically of unburned carbon in fly ash. Good agreement was found between measurement results from the LIBS method and those from the conventional method (Japanese Industrial Standard 8815), with a standard deviation of 0.27%. This result confirms that the measurement of unburned carbon in fly ash by use of LIBS is sufficiently accurate for boiler control. Measurements taken by this apparatus were also integrated into a boiler-control system with the objective of achieving optimal and stable combustion. By control of the rotating speed of a mill rotary separator relative to measured unburned-carbon content, it has been demonstrated that boiler control is possible in an optimized manner by use of the value of the unburned-carbon content of fly ash.

  19. Optimal boiler control through real-time monitoring of unburned carbon in fly ash by laser-induced breakdown spectroscopy.

    PubMed

    Kurihara, Miki; Ikeda, Koji; Izawa, Yoshinori; Deguchi, Yoshihiro; Tarui, Hitoshi

    2003-10-20

    A laser-induced breakdown spectroscopy (LIBS) technique has been applied for detection of unburned carbon in fly ash, and an automated LIBS unit has been developed and applied in a 1000-MW pulverized-coal-fired power plant for real-time measurement, specifically of unburned carbon in fly ash. Good agreement was found between measurement results from the LIBS method and those from the conventional method (Japanese Industrial Standard 8815), with a standard deviation of 0.27%. This result confirms that the measurement of unburned carbon in fly ash by use of LIBS is sufficiently accurate for boiler control. Measurements taken by this apparatus were also integrated into a boiler-control system with the objective of achieving optimal and stable combustion. By control of the rotating speed of a mill rotary separator relative to measured unburned-carbon content, it has been demonstrated that boiler control is possible in an optimized manner by use of the value of the unburned-carbon content of fly ash.

  20. Biomass fly ashes as low-cost chemical agents for Pb removal from synthetic and industrial wastewaters.

    PubMed

    Barbosa, Rui; Lapa, Nuno; Lopes, Helena; Günther, Annika; Dias, Diogo; Mendes, Benilde

    2014-06-15

    The main aim of this work was to study the removal efficiency of Pb from synthetic and industrial wastewaters by using biomass fly ashes. The biomass fly ashes were produced in a biomass boiler of a pulp and paper industry. Three concentrations of Pb(2+) were tested in the synthetic wastewater (1, 10 and 1000 mg Pb/L). Moreover, two different wastewaters were collected in an industrial wastewater treatment plant (IWWTP) of an industry of lead-acid batteries: (i) wastewater of the equalization tank, and (ii) IWWTP effluent. All the wastewaters were submitted to coagulation-flocculation tests with a wide range of biomass fly ashes dosage (expressed as Solid/Liquid - S/L - ratios). All supernatants were characterized for chemical and ecotoxicological parameters. The use of biomass fly ashes has reduced significantly the Pb concentration in the synthetic wastewater and in the wastewaters collected in the IWWTP. For example, the definitive coagulation-flocculation assays performed over the IWWTP effluent presented a very low concentration of Pb (0.35 mg/L) for the S/L ratio of 1.23 g/L. Globally, the ecotoxicological characterization of the supernatants resulting from the coagulation-flocculation assays of all wastewaters has indicated an overall reduction on the ecotoxicity of the crude wastewaters, due to the removal of Pb.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Determination of the Cd-bearing phases in municipal solid waste and biomass single fly ash particles using SR-microXRF spectroscopy.

    PubMed

    Camerani, Maria Caterina; Somogyi, Andrea; Vekemans, Bart; Ansell, Stuart; Simionovici, Alexandre S; Steenari, Britt-Marie; Panas, Itai

    2007-09-01

    By using an excitation energy of 27.0 keV, synchrotron radiation-induced micro-X-ray fluorescence (SR-microXRF) is employed to extract information regarding the composition and distribution of Cd-bearing phases in municipal solid waste (MSW) and biomass fly ashes. Significance of observation is based on statistics of totally more than 100 individual MSW and biomass fly ash particles from a fluidized bed combustion (FBC) plant. Cd concentrations in the parts-per-million range are determined. In general, although previous leaching studies have indicated Cd to be predominant in the smaller-size ash particles, in the present study Cd is more evenly distributed throughout all the particle sizes. For MSW fly ashes, results indicate the presence of Cd mainly as CdBr2 hot-spots, whereas for biomass fly ashes, which exhibit lower CdX2 concentration, a thin Cd layer on/in the particles is reported. For both ashes, Ca-containing matrixes are found to be the main Cd-bearing phases. Support for this observation is found from independent first-principles periodic density functional theory calculations. The observations are condensed into a schematic mechanism for Cd adsorption on the fly ash particles.

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

    PubMed

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

    2009-09-30

    Magnetic fractions (MFs) in fly ashes from eight coal-burning power plants were extracted by magnetic separation procedure. Their mineralogy and potential leachability of heavy metals were analyzed using rock magnetism, X-ray diffraction (XRD), scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (SEM/EDX) and leaching procedures (toxicity characteristics leaching procedure by the United States Environmental Protection Agency, TCLP, and gastric juice simulation test, GJST). Results show that the MFs in the fly ashes range between 2.2 and 16.3wt%, and are generally composed of magnetite, hematite, quartz and mullite. Thermomagnetic analysis and SEM/EDX indicate that the main magnetic carrier magnetite is substituted with small amounts of impure ions, and its structures are featured by rough, dendritic and granular iron spherules. The MFs are found to be rich in Fe, Mn, Cr, Cu, Cd and Pb. Compared with the non-magnetic fractions (NMFs), the MFs have about 5 times higher iron, and 1.6 times higher Mn, Cr, Cu and Cd concentrations. The TCLP test shows that the TCLP-extractable Cr, Cu, and Pb concentrations in the MFs are higher than those in the NMFs, while the TCLP-extractable Cd concentration in the MFs and NMFs is below the detection limit (<0.1mg/L). The GJST-extractable Cd, Cr, Cu, and Pb concentrations in the MFs are higher those in the NMFs. No significant difference in the leachability ratio of Cr, Cu and Pb with TCLP and GJST is found in the MFs and NMFs. However, the GJST test showed that Pb has higher leachability in MFs than that in NMFs. The leachability ratio of heavy metals has an order of Cu>Cr>Pb>Cd. The heavy metals of fly ashes have a great potential to be released into the environment under acid environment.

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

    SciTech Connect

    Tsiridis, V.; Samaras, P.; Kungolos, A.; Sakellaropoullos, G.P.

    2006-08-15

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

  9. Speciation and mobility of volatile heavy metals (Cd, Pb, and Tl) in fly ashes.

    PubMed

    Świetlik, Ryszard; Trojanowska, Marzena; Karbowska, Bożena; Zembrzuski, Włodzimierz

    2016-11-01

    Speciation of volatile metals Cd, Pb, and Tl in fly ashes (FAs) produced from burning of hard coal in stocker-fired boilers (SFBs) was studied. Two grain fractions of fly ash collected in a multicyclone and battery cyclone of the systems of dust separation from three SFB units operating in various urban heating plants were analyzed. The characteristic feature of speciation of the three metals was a large share of labile fractions: Cd (av. 46.1 %), Pb (av. 39.8 %), and Tl (av. 21.6 %). The fraction which most clearly reflected the different chemical properties of the investigated metals was the oxidizable fraction: F(4)-Cd-0 %, F(4)-Pb-av. 10.0 %, and F(4)-Tl-av. 30.2 %. The importance of condensation of the volatile metal species on FA particles for shaping speciation of these metals was characterized using the normalized enrichment factor (NEF): Pb (2.3 ± 0.8) > Tl (1.8 ± 0.9) ≈ Cd (1.7 ± 0.6). Speciation of heavy metals may also be important economically, because the level of mobility coefficients (K Cd = 0.46, K Pb = 0.40, and K Tl = 0.22) in the case of fly ashes considerably enriched with toxic metals (Cd 4.8 ± 3.4 mg/kg, Pb 293 ± 210 mg/kg, and Tl 6.3 ± 4.5 mg/kg) may limit their utilization range.

  10. 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.

  11. Spatial differences in trace element bioaccumulation in turtles exposed to a partially remediated coal fly ash spill.

    PubMed

    Van Dyke, James U; Jachowski, Catherine M Bodinof; Steen, David A; Jackson, Brian P; Hopkins, William A

    2017-01-01

    Large-scale releases of environmental contaminants from industrial facilities can cause considerable damage to surrounding ecosystems and require remediation. The expense and/or undesirable environmental side effects of physical removal may constrain remediation efforts. In 2008, approximately 4.1 million m(3) of fly ash were released into the Emory River at a coal-burning power plant in Kingston, Tennessee, USA. Approximately 390 000 m(3) of fly ash were not removed (hereafter "residual ash"), to avoid disturbing underlying legacy contamination from unrelated historical industrial activity. In 2011 and 2012, the authors measured trace element concentrations in an assemblage of freshwater turtles in 2 rivers impacted by the spill and in a third river that was unaffected. Concentrations of arsenic, copper, iron, mercury, manganese, selenium, and zinc were higher in turtles from rivers affected by the spill but low relative to concentrations known to be toxic to other vertebrates. Concentrations of some trace elements decreased with distance from the original spill site but were not strongly affected by nearby volumes of residual ash. Among-species differences in trace element bioaccumulation and/or the relatively low spatial resolution of available data on residual ash volumes may have obscured this effect. The results suggest that the spill influenced turtle bioaccumulation of trace elements but that distance from the spill site may be a more important factor than residual ash in influencing postremediation bioaccumulation. Environ Toxicol Chem 2017;36:201-211. © 2016 SETAC.

  12. Durability of base course construction using lime stabilized fly ash and flue gas desulfurization sludge by-product

    SciTech Connect

    Beeghly, J.H.; Amaya, P.J.

    1996-12-31

    Fourteen coal-fired power plants in the Ohio Valley totaling 13,500 MW`s use the magnesium-enhanced lime flue gas desulfurization (FGD) scrubbing process. The discharge of these scrubbers is an aqueous slurry of water containing magnesium and calcium sulfites, and solid particles of calcium sulfite and calcium sulfate. Most of these plants dewater the FGD sludge and mix the 35--45% solids cake with coal fly ash and/or bottom ash and pulverized quicklime to cause a cementitious chemical reaction. This type of pozzolanic and hydration reaction can be described as lime reacting with alumina from the fly ash which in turn react with the calcium sulfite and sulfate FGD waste to form ettringite minerals. With a proper mix design and compaction, the resulting material can be used in a beneficial application as a roller compacted FGD base course (RCFGD) for pavement construction. The mix design procedure for RCFGD is described; it includes extra fly ash and lime materials than that used for landfill disposal to yield additional strength and durability. RCFGD was produced in a portable pug mill and placed trying several at a 10,000 sq. ft. cattle feedlot. Mix design criteria and factors affecting strength and durability are discussed. Results of unconfined compression tests as well as of durability tests are reviewed.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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...

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Experimental and statistical determination of indicator parameters for the evaluation of fly ash and boiler ash PCDD/PCDF concentration from municipal solid waste incinerators.

    PubMed

    Streibel, T; Nordsieck, H; Neuer-Etscheidt, K; Schnelle-Kreis, J; Zimmermann, R

    2007-04-01

    On-line detectable indicator parameters in the flue gas of municipal solid waste incinerators (MSWI) such as chlorinated benzenes (PCBz) are well known surrogate compounds for gas-phase PCDD/PCDF concentration. In the here presented work derivation of indicators is broadened to the detection of fly and boiler ash fractions with increased PCDD/PCDF content. Subsequently these fractions could be subject to further treatment such as recirculation in the combustion chamber to destroy their PCDD/PCDF and other organic pollutants' content. Aim of this work was to detect suitable on-line detectable indicator parameters in the gas phase, which are well correlated to PCDD/PCDF concentration in the solid residues. For this, solid residues and gas-phase samples were taken at three MSWI plants in Bavaria. Analysis of the ash content from different plants yielded a broad variation range of PCDD/PCDF concentrations especially after disturbed combustion conditions. Even during normal operation conditions significantly increased PCDD/PCDF concentrations may occur after unanticipated disturbances. Statistical evaluation of gas phase and ash measurements was carried out by means of principal component analysis, uni- and multivariate correlation analysis. Surprisingly, well known indicators for gas-phase PCDD/PCDF concentration such as polychlorinated benzenes and phenols proved to be insufficiently correlated to PCDD/PCDF content of the solid residues. Moreover, no single parameter alone was found appropriate to describe the PCDD/PCDF content of fly and boiler ashes. On the other hand, multivariate fitting of three or four parameters yielded convenient correlation coefficients of at least r=0.8 for every investigated case. Thereby, comprehension of plant operation parameters such as temperatures and air flow alongside concentrations of inorganic compounds in the gas phase (HCl, CO, SO2, NOx) gave the best results. However, the suitable set of parameters suited best for estimation of

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Evaluation of Metals Release from Oxidation of Fly Ash during Dredging of the Emory River, TN

    DTIC Science & Technology

    2011-08-01

    Figure 18. Selenium speciation of the spots defined in (Figure 17) for the original source pile fly ash material using µ-XANES...37 Figure 22. Textural triangle showing the percentages of sand-, silt-, and clay-sized particle in the ash materials ...confined disposal facility – a structure designed to receive sediments dredged from a navigation channel and safely contain the contaminants d

  13. 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.

  14. Dynamic formation of zeolite synthesized from fly ash by alkaline hydrothermal conversion.

    PubMed

    Zhang, ZhiJian; Li, Jiangli; Li, Hongyi; Wang, Hang; Zhu, Jun; He, Qiang

    2013-11-01

    This study was designed to characterize the dynamic formation of zeolite synthesized from fly ash (ZFA) and to identify the zeolitization mechanisms during a 160-h-long hydrothermal alkaline conversion at 95°C by using fly ash (FA) samples collected from four typical thermoelectric power plants in China, with the purpose of improving ZFA quality. The process of synthesizing ZFA can be fundamentally divided into five stages: induction stage (0-0.5 h), accelerating dissolution stage (0.5-12 h), nucleation and/or crystallization stage (12-24 h), crystal growth stage (24-72 h) and crystal transformation stage (72-160 h). The crystal growth stage determined the quality of zeolite crystallization, coupled with functions of re-assembling the silicon-aluminium tetrahedral network and developing submicro- and/or nanometer microstructure