04 By-products related to fuels

concrete products, construction materials for pavement, and construction and fertilizer industries. Possibilities for improving its characteristics for further effective use are also presented.

9am325 Formation of lustrous carbon by two-stage pyro- lysis of coal Buchtele, J. er al. DGMK Tagungsber., 1997, 9703, (Proceedings ICCS ‘97, Volume Z), 833-836. A two-stage pyrolysis process was investigated with regard to the formation of the lustrous carbon in the two-stage process. In the first stage, bituminous hard coal with carbonaceous additive was co-pyrolysed and degasified. In the second stage, the pyrolytic carbon including the lustrous carbon by thermal degradation of volatile products was obtained. The mass balance of the process, carbon- and oxygen balance were evaluated. The forms of pyrolytic carbon were characterized and discussed.

98l90326 FT-i.r. characterization of pitches derived from Avgamasya asphaltite and Raman-Dincer heavy crude Akrami, H. A. er al. Fuel, 1997, 76, (14/15), 1389-1394. Three methods for pitch preparation from Avgamasya asphaltite: (1) solvent extraction; (2) pyrolysis followed by vacuum distillation of the resulting tar; (3) air blowing of some of the vacuum-distilled tars. For Raman-Dincer heavy crude oil, only vacuum distillation was used. Fourier- transform infrared spectroscopy, softening point measurement and ele- mental analysis were used to study the chemical changes resulting from the different processes. Vacuum distillation and air blowing markedly increased the softening point, promoted dehydrogenation and aromatization through significant reduction of aliphatic structures and reduced the H/C atomic ratio. The formation of oxygenated compounds is the major feature of the air blowing technique. The aromaticity and the softening point of solvent- extracted pitches was found to depend on the effectiveness of the solvent.

98lQO327 Impact of fly ash incorporation in soil on germina- tion of crops Kalra, N. et al. Bioresour. Technoi., 1997, 61, (1) 39-41. In order to evaluate the effect of ash incorporation in soil on germination and stand establishment of wheat, chickpea, mustard and lentil during the winter season of 1995, and rice and maize during the summer season of 1996, pot experiments were conducted. Ash levels tested were 0, lo%, 20%, 30% and 40% for winter-season crops, and 0, 5%, lo%, 15% and 20% for summer-season crops, Changes in soil physical and chemical characteristics due to ash addition were analysed. Germination time, defined as the time taken four 75% germination (60% in case of mustard), and delay index, a normalized parameter, were introduced to evaluate ash incorporation effects on germination of crops. Ash addition in soil delayed germination of crops due to the increased impedance offered by the soil matrix to germinating seeds. Rice and maize were relatively less sensitive to ash for germination than winter-season crops. Mustard was most affected for germination and stand establishment. The delay index showed variations between crops, as well as for ash levels, within a crop.

98100328 Incinerator bottom ash as a soil substitute: physi- cal and chemical behavior Rivard-Lentz, D. J. er al. ASTM Spec. Tech. Publ., 1997, STP 1275, 246- 262. Laboratory testing was carried out on bottom ash from one mass-burn incinerator and one refuse derived fuel incinerator. Their physical and chemical properties and behaviour were evaluated. Testing was performed on natural bottom ash and bottom ash amended with other fine grained natural aggregates such as clay and coal fly ash. Bottom ash was shown to be similar in grain size distribution to a well-graded gravelly sand and had lower compacted density and specific gravity than a typical well-graded coarse grained natural aggregate. However, it displayed higher strength properties indicating bottom ash could be used as a structural fill. A significant quantity of ferrous particles remain following processing. The permeability of the bottom ash is similar to well-graded coarse grained natural aggregates but blending of fine-grained natural aggregates can significantly reduce this. The addition of 10% by weight of clay will reduce the permeability sufficiently to meet the US EPA criteria for a landfill cap/ liner. Based on limited TCLP testing the bottom ash is categorized as non- hazardous under US EPA guidelines. However, the levels of some soluble metals and chlorides in the leachate exceed US EPA drinking water standards indicating that for use outside the landfill setting further amendment to the ash is required.

98166329 Influence of tension during oxidative stabilization on SO* adsorption characteristics of polyacrylonltrile (PAN) based activated carbon fibres Lee, J. K. et al. Carbon, 1997, 35, (6), 837-843. Following carbonization, PAN-based carbon fibres were stabilized under various tensions in the presence of air at 230°C and sequentially activated at 950°C. Their SOz adsorption capacity was tested using a thermogravimeter. The magnitude of tension during stabilization and gas environment were varied to study their effects on SO1 adsorption capacity. The tension during the stabilization and the gas atmosphere during activation was found to affect the carbon fibre properties, which are closely related to the SOz adsorption capacity. The effect on the SOz adsorption capacity appeared to stem from their effects on the amount of oxygen functional groups and the

surface area of the carbon fibre. When activated under steam, the PAN fibres displayed the highest SOz adsorption capacity and improved mechanical strength.

98100330 Interactions of carbon-containing fly ash with commercial air-entraining admixtures for concrete Freeman, E. et al. Fuel, 1997, 76, (S), 761-765. The concrete industry provides the most important application for coal ash: as a partial replacement for Portland cement. High levels of unburnt carbon can render ash samples unsuitable for this high-value market by interfering with the action of air-entraining admixtures. These are specialty surfactants used to stabilize air bubbles in concrete mixtures. In order to identify the fundamental interaction mechanisms between fly ash and air-entraining admixtures, an initial laboratory investigation was carried out.

9ai6633f Maize growth and mineral acquisition on acid soil amended with flue gas desulfurization byproducts and magnesium Clark, R. B. et al. Commun. Soil Sci. Plant Anal., 1997, 28, (15116) 1441- 1459. Coal combustion by-products (CCBs) are generated in vast quantities by coal burning power plants. They must be utilized or discarded, and beneficial use of these materials is obviously desired. One such use could be application to agricultural land. Information about the use of one kind of CCB (flue gas desulfurization by-product, FGD-BP) on soil is limited. Maize (Zea mnys L.) was grown on an acid soil, amended with two high CaS04 FCD-BPS and CaC03 at varied calcium/magnesium (Ca/Mg) equivalency ratios to determine treatment effects on growth traits. Results showed maize grown on this acid soil amended with FGD-BPS received benefits when caution was used to alleviate mineral deficiencies/toxicities inherent in the soil.

9aio6332 Mechanical performance of desulfogypsum Molchan, Cl. ef al. FGD Synth. Gypsum, Int. Conf., (Proc.], 5th 1997. 19/l- 19. Edited by Luckevich, L. M. et al., ORTECH, Mississauga, Ont. FGD Gypsum is used by the Lafarge Group as a basic raw material in several plants in Europe. The high purity of this gypsum and its special particle morphology permit high mechanical performance and use as a replacement for natural gypsum. The plasters produced by different calcining processes from different FGD Gypsum (produced from Lignite or Coal fired power stations) are well adapted for plasterboard and plasterblock manufacture.

98100333 Melting of coal ashes in converter-type furnace and feeding of coal ashes using a carrier gas Takahashi, K. er al. Jpn. Kokai Tokkyo Koho JP 09,257,228 [97,257,228] (Cl. F23G5/44), 30 Sep 1997, Appl. 96193,262, 22 Mar 1996, 8 pp. (In Japanese) Power plants coal ash is fed from a lock hopper and blown with a carrier gas into the molten slag and pig iron bed of a converter-type melting furnace. Carbonaceous materials are used as a heating source, Oz and slag-forming materials are also injected through a lance nozzle into the molten slag and pig iron bed for melting the ashes. The ratio of coal ashes to the carrier gas during feeding was controlled at >20:1 under certain test conditions.

98106334 Mesoporous activated carbons with metal-oxide particles prepared from Morwell coal Yushizawa, N. et al. Sekitan Kagaku Kaigi Happy0 Ronbunshu, 1996, 33, 249-252. (In Japanese) A mixture of Murwell coal and metal (Fe, Ni, Cu) complex was used to prepare activated carbons with selective mesoporosities. The pure structure of the activated sample were determined with Nz adsorption isotherms and metal-oxide particles include in the carbon matrix were characterized with x-ray diffraction patterns and TEM photographs. The formation of mesopores in the activated carbons is suggested to be related with migration of oxide particles. Also discussed was the dependence of metal kinds upon pore structure.

98166335 Method for preparing fly ash for high compressive strength concrete and mortar, and compositions thereof Liskowitz, J. W. et al. PCT Int. Appl. WO 97 21,640 (Cl. C04B14100). 19 Jun 1997, US Appl. 8,690, 15 Dee 1995, 52 pp. This method can be applied to concrete, mortar and other hardenable mixtures comprising cement and fly ash for use in construction. The invention relates to hardenable mixtures comprising cement and fly ash which can achieve greater compressive strength than those containing only concrete over the time period relevant for construction. In a specific example, processing fly ash by grinding to the desired size distribution range gives a 100% yield of fly ash for utilization in high quality concrete and mortar. Construction costs can be reduced via these materials, as well as providing a useful outlet for material that is generally regarded as a pollutant and a nuisance.

Fuel and Energy Abstracts January 1996 27