00352 Structure and properties of water-soluble humic substances of peat

05 Rheological and surface properties of coal-tar used 96loo35o in the composition of self-baking anodes of ore-reducing electric furnaces Grinshpunt, A. G. K&n. Tverd. To@. (Moscow), 1997, (2), 70-75. (In Russian) The author provides experimental data concerning the rheological properties of coal tar used as component in the manufacture of self-baking anode masses of ore-reducing electric furnaces are given. The softening temperature of the electrode mass is 12-17°C and during meltingsolidification cycles, characteristic structural changes were determined. The best wetting of the anode mass components with tar was determined at 170-175°C and 195”C, respectively, depending on the physicochemical properties and origin of tar. Rheological properties of coal-tar pitches 98lOO351 Duber, S. et al. Karbo-Energochemicai-Ekol., 1996, 41, (3), 85-89. (In Polish) The rheology of a set of coal tar pitches and coal tar pitch binders was studied and applied recently in carbon and/or graphite electrodes manufacturing. In general, the flow curves were expressed by a rheology equation of Bingham plastics. In higher temperatures the intercept of model equation decreased to 0, thus the pitches show properties of Newtonian fluid. Based on values of flow activation energy, transition temperature and viscosity, used as a material constants. essential differences were found among the investigated materials. Structure and properties of water-soluble humic 98100352 substances of peat Dudarchik, V. M. et al. Khim. Tverd. Top/., 1997, (2), 13-18. (In Russian) ‘jC NMR spectroscopy was used to examine the structure of humic acids in peat and products of their oxidation destruction. Water-soluble products of oxidation destruction are highly oxidized fragments of humic acids enriched with O-containing functional groups and having a high cation-absorption capacity. Studies of fly ash using thermal analysis 98100353 techniques Li, H. et al. J. Therm. Analysis, 1997, 49, (2), 943-951. It is possible to quantitatively identify various fly ash components from a laboratory-scale fluidized bed combustion system with recently-developed improved thermoanalysis methods. The thermogravimetric procedure developed can determine quantities of HlO, Ca(OH)*, CaC03, CaSOz and carbonaceous matter in fly ash with accuracy comparable to more timeconsuming ASTM methods. It is a modification of the Mikhail-Turcotte methods that can accurately analyse bed ash with higher accuracy regarding the greater amount of carbonaceous matter in fly ash. Furthermore, in conjunction with Fourier transform IR and SEMIEDS analyses, the reduction mechanism of CaSO? as CaSOz + 4Hz ct CaS + 4Hz0 was confirmed. This mechanism is important in analysing and evaluating S capture in fluidized-bed combustion systems. Study of the polymerization of pitches during their 90100354 heat treatment under argon- and air-blowing conditions Martin, Y. et al. DGMK Tagungsber., 1997, 9703, (Proceedings ICCS ‘97, Volume 2). 881-884. In order to investigate the chemical reactions involved in the pyrolytic process, a coal tar pitch and a petroleum pitch were heat treated under gas blowing conditions with air and Ar at 350 and 425°C. The polymerization and condensation reactions were studied by the analysis of the toluene soluble (TS) fractions of the pitch and the volatile compounds by HPLC. Clear differences were found between the experiments in air and in Ar. Under air-blowing conditions, the TS material was produced via the formation of peri-condensed compounds, whereas the use of Ar as blowing gas resulted in the cata-condensed compounds reacting to yield TS material, probably through the formation of crosslinks without forming peri-condensed intermediates. In the case of petroleum pitches, with a high content on alkyl side chains, the formation of crosslinked structures played an important role in the increase of TS material. Study on activated fly ash as an adsorbent for Weak 98100355 Acid Brilliant Green GS Shao, Y. et al. Gongye Shuichuli, 1997, 17, (1). 21-23, 27. (In Chinese) Original fly ash was mixed with slaked lime and then heated to produce activated fly ash. The effect of lime content and temperature on the ability of the product to adsorb Weak Acid Brilliant Green GS dye was studied. The saturation adsorption capacity of the best product was 47 times that of inactivated fly ash. The removal of COD in wastewater was 90% and the decolorization was ~90%. The structure of the activated fly ash and its adsorbing mechanism were studied by TGA, DTA, and IR. Study on correlation between chemical and mineral 98100356 composition of coal ashes Hirato, M. ef al. Sekitan Kagaku Kaigi Happy0 Ronbunshu, 1996, 33, l41144. (In Japanese) The composition of coal ash has generally shown the chemical composition, but from a practical point of view, the ash has a mineral composition as well. So, the correlation between chemical and mineral composition in the coal ash was clarified by use of the equation of material balance.

Nuclear fuels (scientific, technical)

Toward the development of a superior binder for 96loo357 carbon materials Martin, S. C. et al. DGMK Tagungsber., 1997, 9703, (Proceedings ICCS ‘97, Volume 2), 885-888. Analysis of a known coal-tar pitch, three unknown coal-tar pitches, and a petroleum pitch was carried out concerning their hydrocarbon composition by HPLC. Thermogravimetric analyses were performed between 30 and 950°C under Nz and weight losses were recorded as a function of the temperature to determine the temperature of maximum weight loss. A quantitative method could be developed to ascertain the correlation between the molecular composition of the pitch, its reactivity, and the properties of the resulting cokes. The investigation were results proved useful for the manufacture of industrial carbon anode material with the pitches as binder material. The use of coke-oven gas and natural gas for 98100358 production of carbon black Fratzscher, H. and Vosshenrich, R. Gaswaerme by., 1997, 46, (lo), 474478. (In German) The manufacturing processes and raw materials for industrially produced carbon black, together with properties regarding the wide range of applications, are discussed. Carbon black production is based on hydrocarbons which are split into carbon and hydrogen, either thermally or thermo-oxidatively. Regarding the raw materials and energy carriers coal tar oil, petroleum products, and natural gas, a commercial carbon black manufacturing process is outlined. Utilization of iron oxides from coal ash of thermal 9aioo359 power plant wastes Pavlenko, S. I. and Ni, L. P. Kompleksn. Ispol’z. Miner. Syrj,a, 1996, (5), 63-69. (In Russian) AlZ03, silicate products, and Fe can be obtained from coal ash processing. Magnetic separation and alkali leaching produces concentrates containing >80% Fe oxides. Zeolites synthesized from class F fly ash and 96100360 sodium aluminate slurry Grutzeck. M. W. and Siemer. D. D. .I. Am. Ceram. Sot.. 1997. 80. 191. \,, 2449-2453.

In an attempt to synthesize zeolites from a highly alkali waste stream, a Class F fly ash was combined with a sodium aluminate slurry (3:l Na:AI). The reaction was studied as a function of composition (3:2, i:l, and 1:2 fly ash:slurry), time (1, 3, and 7 days), and temperature (80, 130, and 180°C). X-ray diffraction analyses of the products indicated that the fly ash and sodium aluminate had combined to form Zeolite A at 8O”C, and NaPl (a gismondine-type) and an unnamed hydroxysodalite-type at 130°C and 180°C. The fact that the pH of the reactants decreased from initial values in excess of 13 to near neutral after reaction signifies that the bulk of the sodium had been incorporated into zeolitic phases. Due to the unique adsorptive and cation exchange capabilities of zeolites and the fact that some samples formed reasonably hard monoliths, zeolitic materials formed in this way might make excellent waste forms for ‘mixed wastes’ which contain both radioactive and hazardous chemical species.

05

NUCLEAR Scientific,

FUELS

Technical

96100361 Analysis of the steam generator for the safe integral reactor concept: I. Steady state Kuridan, R. M. and Beynon, T. D. Progress in Nuclear Energy, 1997, 31, (3), 273-287.

The paper describes a steady state model for the safe integral reactor (SIR) once-through steam generator with the objective of thermal performance prediction. The model takes into account the special features and conditions of the steam generator. The appropriate heat transfer correlations are utilized in each heat transfer regime, especially in the post dry-out region where thermodynamic non-equilibrium is expected. The results are compared other independent work. 98100362 Analysis of the steam generator for the safe integral reactor concept: II. A linearized non-steady state model Kuridan, R. M. and Beynon, T. D. Progress in Nuclear Energy, 1997, 31, (3), 289-301. A linearized non steady state model of the Safe Integral Reactor (SIR) steam generator was developed, based on an earlier steady state model. Two models were derived for the nucleate boiling regime. The first model was based on the assumption that any changes in the heat addition or loss or flow perturbations would affect only the vaporization or condensation. In the second model, the saturation temperature, and hence the saturation

Fuel and Energy Abstracts

January 1998

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