12 Refractories/ceramics (properties, production, applications)

97/01405 Manufacture of molten pig iron from scrap and iron- ore charge heated by combustion on a coke bed in vertical furnace Yamaoka, H. er ol. Indian IN 173, 766 (Cl. C2lBll!OO). 9 Jul 1994. Appl. 89/MA839, 16 Nov 1989; 72 pp. Explains how the coke bed in a furnace is maintained over the vertically positioned bottom tuyeres, a packed bed of scrap and granular Fe ore is loaded on top of the coke bed and the Fe-ore fines are injected with a gas through the secondary side tuyeres for smelting to manufacture pig iron. The hottom tuyeres are used to inject carbonaceous fuel with an oxidizing gas for heating the furnace by a partial combustion to CO gas, and molten pig iron and slag are discharged near the bottom. The molten pig iron can be manufactured by smelting the Fe-ore fines with decreased consumption of coke.

97101406 Manufacture of sintered iron ores with fuels from wastes Koni\hi. Y. and Ooyama, N. Jpn. Kokai Tokkyo Koho JP OX, 246, 069 196. 246. 069) (Cl. C22Bl116). 24 Sep 1996. Appl. 95’52, 442. I3 Mar 1095, 6 pp (In Japanese). Describes the use of solid fuels obtained from domestIc rubbishes as a part of fuels. The process provides improved ventilation and low coqt.

97101407 Method and apparatus for removal of copper series impurity from iron scrap Izumyama, M. CI al. Jpn. Kokai Tokkyo Koho JP 08, 188. X36 [96, 188. 8301 (Cl. C2287100). 23 Jul 199f1, Appl. 951659, 6 Jan 1995, 7 pp (In Japanese). Details a method and apparatus for the removal of copper series impurity from iron scrap. The method comprises: (1) precooling scrap during conveying, (2) bringing the scrap into contact with liquefied gas to promote emhrittlement. (3) crushing the scrap at low temperature, (4) magnetic separating the crushed scrap, and (5) returing the coarse fraction [particle diameter 225 mm) to the crushing stage. An apparatus for the above procsss i\ claimed for the recovery of pure iron from automotive scrap.

97101408 Modeling of the Corex (smelting reduction) hot metal process Pichestapong, P. and Rao. Y. K. Challenges Process In!cvnifx Proc. Int. Sump., 1996, 67-83. Edited by Pickles, C. A. et al., Canadian Institute of Mining, Metallurgy and Petroleum, Montreal, Que. The Corex process uses limestone and dolomite fluxes to ensure a basic slag and efficient desulfurization. The energy consumption for the Corex process compares favourably with that of the blast furnace.

97101409 Successful development and future prospects for injection technology of blast furnace in Japan Inaba. S. Injection Technol. Ironmuking Sfeelmakirtg, Tech. E.rch. Sess.. 1995 (PUh. 1996). 47-57. Discusses auxiliary fuel use in ironmaking blast furnaces, with an emphasis on pulverized coal.

97/01410 Three-stage fluidized-bed furnace system for direct reduction of powdered iron ores and fines recovery with cyclones Lee, I. 0. et al. PCT Int. Appl. WO 96 21, 044 (Cl. C21Bl3/14), II .Iul 1996, KR Appl. 9, 438, 980, 2’9’Dec 1994, 75 pp. The serially arranged system described in this article comprises a drying- preheating furnace with a first cyclone, a primary reduction furnace with a second cyclone, a secondary high-gas-velocity reduction furnace for finally reducing only a coarse portion of the prereduced ore, a secondary low-gas- velocity reduction furnace for finally reducing the medium and fine ore particles and containing interior cyclone. and a third cyclone for recovering dust not captured by the internal cyclone. The reducing gas consists of CO and H2. The direct-reduction stages are typically operated at 800-900”. gas pressure of 2-4 atm, and gas velocity 1.5-3 times the minimum tluidizatian velocity related to the are particle size. This system is capable of handling Fe ores of wide particle size range. The reduced ore is fed into a melter- gasifier unit to obtain pig iron for steelmaking. The various arrangements of fluidized beds and cyclones are discussed with schematic flow diagrams.

12 REFRACTORIES/ CERAMICS

Properties, Production, Applications

97101411 Advanced ceramic materials for use in high-tem- perature particulate removal systems Alvin, M. A. I& Eng. Chem. Ra.. 1996, 35. (IO). 33X4-339X. A review of advances recently made during the development of second- generation porous ceramic filter materials. InGght is given into the performance of the filter elements during bench-scale qualification testing and operation in demonstration plant test facilities. First-generation monolithic porous ceramic filter materials have experienced thermal fatigue. high-temperature creep, and a loss of material strength when operated for extended periods of time in advanced coal-fired combustion and gasification systems. Fiber-reinforced and advanced ceramic compo- sites potentially provide a means to mitigate the degradation mechanisms encountered by monohthic filter matrixes and ultimately extend operating life.

97101412 Cemfuel-a fuel for cement kilns Walpole, I. Case Stud. Environ. Tcchnol., 1996. 137-149 (Edited by Sharratt, P. and Sparshott, M.). Institution of Chemical Engineer\. Kughy. UK. A discussion of Cemfuel--a highly specified liquid fuel, manufactured front certain selected waste streams. Cemfuel is part ot the he\t practicahlc environmental option for cement manufacture

97101413 Characterization of Australian and New Zealand fly ashes for concrete manufacture Jo. Y. M. (‘I al. A&,. Cem. Res., 199h. 8. (29). 21-27. The chemical and physical propertics of nine different Australian and New Zealand fly ashes were determined in order to relate them to the pozzolanic properties of the ashes (with a view to utilization as a cement additive in the manaufacture of concrete). It was found that, while the ashes produced from bituminous and subbituminous coal were generally acceptable as a pozzolanic source, two of three tested ashes produced from brown coal did not meet the required standards. Some ashes, in particular the Loy Yang ash, were found with some additional treatment to be potential pozzolanic additives.

97101414 Coal cinders: an alternative raw material for bricks Meja de Gutierrez. R. and Delvasto, S. Ceramur~ia. 1996. 26, (I), 11-13. (In Italian) Colombian electrical utilities produce approximately 270, 000 tons of fly ash and 54,000 tons of coal bottom ash anually. In this research it has been demonstrated that the bottom ash is an excellent raw material to produce semi-dry press burnt bricks. Mixes of graded bottom ash and a plastic clay were prepared for brick molding. The best results were obtained with a proportion of 75 wt.% of the coal waste. The bricks were pressed at 35 MPa and burnt by controlled firing up to 1100°C. ‘The bricks reported an average compressive strength of 8.94 MPa. The quality of the bricks was higher than the type 111 bricks strength specified by Colombian Standards for load bearing walls.

97101415 Determining thermal diffusivity and defect attri- butes in ceramic matrix composites by infrared imaging Ahuja, S. et ul. Proc. SPIE-lnt. Sm. Opt. Erg.. 1996. 2766 (Thermosense XVIII: An International Conference on Thermal Sensing and Imaging Diagnostic Applications), 249-257. Discusses the development of ceramic matrix composites for numerous high temperature applications, including heat exchanger and hot-gas filters for coal gasification plants. Among the materials of interest are silicon carbide fiber-reinforced silicon carbide matrix composites. During the manufacture of these ceramic composites, the conditions of the fibre/matrix interface are critical to the mechanical and thermal behaviour of the component. Defects can directly affect the performance. A non-destructive evaluation (NDE) method has proved beneficial in analyzing as-processed conditions and defect detection created during manufacture. This NDE method uses IR thermal imaging for full-field quantitative measurement of the distribution of thermal diffusivity in large components. Intensity transform algorithms have been used for contrast enhancement of the output image. Non- uniformity correction and automatic gain control are used to dynamically optimize video contrast and brightness, providing additional resolution in the acquired images. Digital filtering, interpolation, and least-squares- estimation techniques have been incorporated for noise reduction and data acquisition. The Argonne NDE system has been utilized to determine thermal shock damage, density variations, and variations in fibre coating in a full array of test specimens.

Fuel and Energy Abstracts March 1997 111