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05770 Modern environmentally acceptable technologies in coal processing
01
Solid fuels (preparation)
96105754 Components of the surface free energy of low-rank coals In the presence of n-alkanee Janczuk,B. et al., Powder Technol., 1996, 86, (3), 229-238. Measurements of wntact angles for water, glycerol, formamide and diiodomethane on the surfaces of four low-rank coals covered with nalkanes were studied. Demlnerallzatlon of a bltumlnous coal by froth flo66105755 tation before obtaining activated carbons Rivera-Utrilla, J. et al., Carbon, 1996, 34, (7), 917-921. A Spanish bituminous coal has been demineralized by froth flotation. The effect of the particle size, solution pH, and the presence of electrolytes on the process yield has been investigated. The ash contents of the clean coal have been riduced by between 1.5-3 times with regard to the wrresponding feed coal. Three activated carbon samples have been obtained by steam activation of the floated coal. Dry coal cleaning process for hlgh-quality coal 96106756 Tanaka, 2. et al., J. Chem. Eng. Jpn., 1996, 29, (2), 257-263. Describes the development of a dry coal cleaning process for cleaning fine and ultrafine coal to obtain a high-quality coal. A classification column was used for fine coals and a centrifugal classifier was used for cleaning ultrafine coal particles. Some coals were cleaned into a high-quality coal that contained-<1 wt.% ash wntent using a fluidized classifiatibn column. For finely ground coal, ash was concentrated in the ultrafine coal fraction. The effect of growth medium of Thiobaclllus fer96105757 rooxldans on pyrite flotatlon Misra, M. et al.; -Miner. Eng., 1996, 9, (2), 157-168. The bacterium, Thiobacillus ferrooxidans, has been used for the depression of pyrite during the flotation separation of coal particles from associated minerals. However, the utilization of T. ferrooxidans as a regulator in the differential flotation of sulphide minerals has not yet been established. The objective of the present study is to determine if T. ferrooxidans can be used for the selective depression of pyrite. Effect of oxldetlon on the rate of agglomeration of 96105766 coal with oil t&lyi8F W. andWheelock, T. D. Fuel Sci. Technol. Int., 1996, 14, (4), The paper discusses the effect of coal surface properties and other parameters on the rate of agglomeration. Two types of bituminous coal were utilized, and the surface properties of each type were varied by heating in air. The rate of agglomeration depended on both the rank of the coal and the extent of oxidation of the coal. Effect of saline water on flotation processing of 96105759 coal Botula, J. and Repka, V. Uhli-Rudy-Geol. Pruzkum, 1996, 3, (1). 13-14. (In Czech) _ Reports that there is no statistically s$nificant effect of water salinite (either salt concentration or composition) on the efficiency of coal flotation. Ex rlmental study on mass transfer In moisture uptake by drle8”coal Liu, Y. and Tang, X. Huaxue Gongye Yu Gongcheng (Tianjin), 1996, 13, (l), 1-4. (In Chi&se) An investigation was made of moisture uptake by dried coal. There are three characteristic stages of the process. The effects of environment, coal size, initial moisture wntent and the method of drying on the process are analyzed. 96105760
96105761 Froth flotation - The Importance of the froth Hall, S. Mining Magazine, Jul. 1996, 175, (1). 16-17. The author discusses how over recent years numerous novel flotation technologies have been promoted with various degrees of commercial success. Most of these novel technologies have developed, or redesigned, methods of contacting air bubbles and reagentised mineral particles in the pulp phase. It is however in the froth phase that the essential processes of particle transport to the concentrate launder and drainage to remove gangue entrainment occur. 96105762
Hydrothermal reactlon of Ca(OH), with quartz In coal Wang, J. et al., Prepr. Pap.-Am. Chem. Sot., Div. Fuel Chem., 1996, 41, (2), 628-631. Quartz is generally most abundant as mineral matter in coal. A study was made in order lo obtain fundamental information for chemical demineralization of coal with Ca(OH),, and the hydrothermal reaction of Ca(OH), with reagent quartz.
412
Fuel and Energy Abstracts November 1996
96105763 lndlcer for coal desulfurlzatlon and de-ashlng processes Petela, R. and Petela, G. Fuel, Sep. 1996, 75, (ll), 1259-1266. Coal upgrading processes are evaluated based on performance indices. Adequate definitions of these indices are very important because the process ooeratinn oarameters are adiusted bv a control svstem accordins to the required valued of the indices. he pape; discusses ihe following p&formante indices for physical processes of coal desulphurization and demineralization: coal matter recovery, total sulphur- rejection, ash rejection, inorganic sulphur rejection, umt index of sulphur rejection, unit index of ash rejection, joint unit index of sulphur and ash rejection, and overall index of coal upgrading. The deficiences of the existing definitions of these indices are pointed out and new, more adequate indices are proposed. 96lO5764 Influence of high-temperature treatment up to 24OO’C on structural parameters of cokes produced from coal wlth some addltlves Legin-Kolar, M. and Radenovic, A. Coal Sci. Technol., 1995, 24, 1037-1040. The crystallography and optical parameters of coke depended on the type of additive and heating temperature. Among the coke samples examined, the highest L, value was 16.8 nm for coke heated at 2400’, heating time 4 h and heating rate 10 Khnin. 96105765 Influence of natural weatherlng of two coking coals of similar rank on coke aualitv Alvarez, R. et al., Coal Sci: fech;ol., 1995, 24, 1081-1084. A studywas carried out in order to estimate the optimum storage time for these coals, their structural changes, coking properties, and coke quality. 96105766 Keeplng It clean Lang, D. Mining Voice, Jul.-Aug. 1996, 2, (4), 34-38. Describes how coal, one of the ‘dirtiest’ fossil fuels, has undergone a personality change in recent years. Thanks to new technologies, it’s now a neat and tidy energy source. 96105767
Klnetlc and structural studies of calcium-based sorbents for hlgh-temperature coal-gas desulphurlzatlon Fenouil, L. A. and Lynn, S. Fuel Sci. Technol. Int, 1996, 14, (4), 537-557. The absorption of H,S by large particles of limestone, dolomitic limestone
and dolomite was tested under simulated coal gases. Below the calcination temperature of CaCO,, complete conversion of the calcium carbonate to calcium sulohide can onlv be achieved with dolomite. Above the calcination temperiture of CaCd,, the conversion to CaS is complete for all three sorbents in about one hour when 10,000 ppm H,S is present in the gas phase. Large particles of limestone thus appdar to be a s&table sorbent Tar high-temperature coal-gas desulphurization. A mathematical model based on the kinetic information collected in this work predicts the desulphurizadon performance of a packed or moving bed of limestone particles. 96105766 Llgand as&ted desulfurizatlon of llgnlte using the perchloroethylene coal refining process Tartamella, T. er al., Fuel Sci. Technol. Int, 1996, 14, (4), 503-509. The perchloroethylene coal refining process was used on North Dakota lignite coal. The effects of extractIon time, .oerchloroethvlene-coal ratio and _ artificial weatherin were studied to determine thei; effects on the removal of organic sulpa ur. 96105769 Low temperature conversion of coals through Intercalation and nucleophlllc reactions Kucherenko, V. A. et al., Coal Sci. Technol., 1995, 24, 865-868. Describes how coal, especially coking coal, is treated with acetyl nitrate, which leads to NO, evolution, coal swelling, weight uptake, a decrease in unpaired electron concentration, and a special reorganization of coal framework.Water pyrolysis of this treated coal changes its structure and transforms it into compounds called coal hydrates. 96105770 Modern envlronmentally acceptable technologies in coal processing 1995, 40, (12), Hoelter, H. and Weber, A. Karbo-Energochem-Ekol, 307-310. (In Polish) A review of new plants for the beneficiation coal flotation rejects, pyrite removal from coal and processing of mine dumps. 96105771 Power from coal: Where to remove Imourltles Couch, G. R. ISBN-92-9029-257-1, Order No. UKIEACR,r1996, 89 pp. The study considers both the constraints and the opportunities which apply to the removal of impurities from coal at all stages of the coal-to-electricity chain. Discusses the commercial and regulatory background, which varies considerably from country to country. Much depends on whether there is competition in the local market when purchasers will probably switch supplies before considering additional coal cleaning.
Solid fuels (preparation)
96105754 Components of the surface free energy of low-rank coals In the presence of n-alkanee Janczuk,B. et al., Powder Technol., 1996, 86, (3), 229-238. Measurements of wntact angles for water, glycerol, formamide and diiodomethane on the surfaces of four low-rank coals covered with nalkanes were studied. Demlnerallzatlon of a bltumlnous coal by froth flo66105755 tation before obtaining activated carbons Rivera-Utrilla, J. et al., Carbon, 1996, 34, (7), 917-921. A Spanish bituminous coal has been demineralized by froth flotation. The effect of the particle size, solution pH, and the presence of electrolytes on the process yield has been investigated. The ash contents of the clean coal have been riduced by between 1.5-3 times with regard to the wrresponding feed coal. Three activated carbon samples have been obtained by steam activation of the floated coal. Dry coal cleaning process for hlgh-quality coal 96106756 Tanaka, 2. et al., J. Chem. Eng. Jpn., 1996, 29, (2), 257-263. Describes the development of a dry coal cleaning process for cleaning fine and ultrafine coal to obtain a high-quality coal. A classification column was used for fine coals and a centrifugal classifier was used for cleaning ultrafine coal particles. Some coals were cleaned into a high-quality coal that contained-<1 wt.% ash wntent using a fluidized classifiatibn column. For finely ground coal, ash was concentrated in the ultrafine coal fraction. The effect of growth medium of Thiobaclllus fer96105757 rooxldans on pyrite flotatlon Misra, M. et al.; -Miner. Eng., 1996, 9, (2), 157-168. The bacterium, Thiobacillus ferrooxidans, has been used for the depression of pyrite during the flotation separation of coal particles from associated minerals. However, the utilization of T. ferrooxidans as a regulator in the differential flotation of sulphide minerals has not yet been established. The objective of the present study is to determine if T. ferrooxidans can be used for the selective depression of pyrite. Effect of oxldetlon on the rate of agglomeration of 96105766 coal with oil t&lyi8F W. andWheelock, T. D. Fuel Sci. Technol. Int., 1996, 14, (4), The paper discusses the effect of coal surface properties and other parameters on the rate of agglomeration. Two types of bituminous coal were utilized, and the surface properties of each type were varied by heating in air. The rate of agglomeration depended on both the rank of the coal and the extent of oxidation of the coal. Effect of saline water on flotation processing of 96105759 coal Botula, J. and Repka, V. Uhli-Rudy-Geol. Pruzkum, 1996, 3, (1). 13-14. (In Czech) _ Reports that there is no statistically s$nificant effect of water salinite (either salt concentration or composition) on the efficiency of coal flotation. Ex rlmental study on mass transfer In moisture uptake by drle8”coal Liu, Y. and Tang, X. Huaxue Gongye Yu Gongcheng (Tianjin), 1996, 13, (l), 1-4. (In Chi&se) An investigation was made of moisture uptake by dried coal. There are three characteristic stages of the process. The effects of environment, coal size, initial moisture wntent and the method of drying on the process are analyzed. 96105760
96105761 Froth flotation - The Importance of the froth Hall, S. Mining Magazine, Jul. 1996, 175, (1). 16-17. The author discusses how over recent years numerous novel flotation technologies have been promoted with various degrees of commercial success. Most of these novel technologies have developed, or redesigned, methods of contacting air bubbles and reagentised mineral particles in the pulp phase. It is however in the froth phase that the essential processes of particle transport to the concentrate launder and drainage to remove gangue entrainment occur. 96105762
Hydrothermal reactlon of Ca(OH), with quartz In coal Wang, J. et al., Prepr. Pap.-Am. Chem. Sot., Div. Fuel Chem., 1996, 41, (2), 628-631. Quartz is generally most abundant as mineral matter in coal. A study was made in order lo obtain fundamental information for chemical demineralization of coal with Ca(OH),, and the hydrothermal reaction of Ca(OH), with reagent quartz.
412
Fuel and Energy Abstracts November 1996
96105763 lndlcer for coal desulfurlzatlon and de-ashlng processes Petela, R. and Petela, G. Fuel, Sep. 1996, 75, (ll), 1259-1266. Coal upgrading processes are evaluated based on performance indices. Adequate definitions of these indices are very important because the process ooeratinn oarameters are adiusted bv a control svstem accordins to the required valued of the indices. he pape; discusses ihe following p&formante indices for physical processes of coal desulphurization and demineralization: coal matter recovery, total sulphur- rejection, ash rejection, inorganic sulphur rejection, umt index of sulphur rejection, unit index of ash rejection, joint unit index of sulphur and ash rejection, and overall index of coal upgrading. The deficiences of the existing definitions of these indices are pointed out and new, more adequate indices are proposed. 96lO5764 Influence of high-temperature treatment up to 24OO’C on structural parameters of cokes produced from coal wlth some addltlves Legin-Kolar, M. and Radenovic, A. Coal Sci. Technol., 1995, 24, 1037-1040. The crystallography and optical parameters of coke depended on the type of additive and heating temperature. Among the coke samples examined, the highest L, value was 16.8 nm for coke heated at 2400’, heating time 4 h and heating rate 10 Khnin. 96105765 Influence of natural weatherlng of two coking coals of similar rank on coke aualitv Alvarez, R. et al., Coal Sci: fech;ol., 1995, 24, 1081-1084. A studywas carried out in order to estimate the optimum storage time for these coals, their structural changes, coking properties, and coke quality. 96105766 Keeplng It clean Lang, D. Mining Voice, Jul.-Aug. 1996, 2, (4), 34-38. Describes how coal, one of the ‘dirtiest’ fossil fuels, has undergone a personality change in recent years. Thanks to new technologies, it’s now a neat and tidy energy source. 96105767
Klnetlc and structural studies of calcium-based sorbents for hlgh-temperature coal-gas desulphurlzatlon Fenouil, L. A. and Lynn, S. Fuel Sci. Technol. Int, 1996, 14, (4), 537-557. The absorption of H,S by large particles of limestone, dolomitic limestone
and dolomite was tested under simulated coal gases. Below the calcination temperature of CaCO,, complete conversion of the calcium carbonate to calcium sulohide can onlv be achieved with dolomite. Above the calcination temperiture of CaCd,, the conversion to CaS is complete for all three sorbents in about one hour when 10,000 ppm H,S is present in the gas phase. Large particles of limestone thus appdar to be a s&table sorbent Tar high-temperature coal-gas desulphurization. A mathematical model based on the kinetic information collected in this work predicts the desulphurizadon performance of a packed or moving bed of limestone particles. 96105766 Llgand as&ted desulfurizatlon of llgnlte using the perchloroethylene coal refining process Tartamella, T. er al., Fuel Sci. Technol. Int, 1996, 14, (4), 503-509. The perchloroethylene coal refining process was used on North Dakota lignite coal. The effects of extractIon time, .oerchloroethvlene-coal ratio and _ artificial weatherin were studied to determine thei; effects on the removal of organic sulpa ur. 96105769 Low temperature conversion of coals through Intercalation and nucleophlllc reactions Kucherenko, V. A. et al., Coal Sci. Technol., 1995, 24, 865-868. Describes how coal, especially coking coal, is treated with acetyl nitrate, which leads to NO, evolution, coal swelling, weight uptake, a decrease in unpaired electron concentration, and a special reorganization of coal framework.Water pyrolysis of this treated coal changes its structure and transforms it into compounds called coal hydrates. 96105770 Modern envlronmentally acceptable technologies in coal processing 1995, 40, (12), Hoelter, H. and Weber, A. Karbo-Energochem-Ekol, 307-310. (In Polish) A review of new plants for the beneficiation coal flotation rejects, pyrite removal from coal and processing of mine dumps. 96105771 Power from coal: Where to remove Imourltles Couch, G. R. ISBN-92-9029-257-1, Order No. UKIEACR,r1996, 89 pp. The study considers both the constraints and the opportunities which apply to the removal of impurities from coal at all stages of the coal-to-electricity chain. Discusses the commercial and regulatory background, which varies considerably from country to country. Much depends on whether there is competition in the local market when purchasers will probably switch supplies before considering additional coal cleaning.