Effect of temperature on cementite formation by reaction of iron ore with H 2 -CH 4 -Ar gas
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most likely saturated with alumina from the crucible. This suggests that agglomeration of alumina can occur at slagmetal interfaces when the slag is saturated with respect to alumina or the alumina dissolution rate is low. In the current article, inclusions at a slag metal interface were observed for the first time in situ with a scanning laser microscope. The separation across the interface into the slag was only observed for one of the four observed types of inclusions (type B). Agglomeration of solid inclusions and liquid inclusions capturing solid ones was seen to occur at the interface. These results suggest that the rest time for inclusions at slag metal interfaces depends considerably on the inclusion type and may be quite long in industrial vessels such as ladle, tundish, and mold. It is thus important to tailor the inclusions not only with respect to subsequent rolling operations but also with respect to achieving a rapid separation across the interface. The inclusions that do separate relatively rapidly do so depending on the curvature of the meniscus. If they hit the interface at a highly curved surface, then they travel upward along the meniscus and separate or occasionally get re-entrained at the top of the meniscus. REFERENCES 1. H. Chikama, H. Shibata, T. Emi, and M. Suzuki: Mater. Trans. JIM, 1996, vol. 37 (4), pp. 620-26. 2. C. Orrling, Y. Fang, N. Phinichka, S. Sridhar, and A.W. Cramb: JOM-e, 1999, vol. 51 (7), http://www.tms.org/pubs/journals/JOM/ 9907/Orrling/Orrling-9907.html. 3. P.A. Kralchevsky, K.D. Danov, and N.D. Denkov: in Handbook of Surface and Colloid Chemistry, K.S. Birdi, ed., CRC Press, Inc., Boca Raton, Fl, pp. 362-70. 4. H. Yin, H. Shibata, T. Emi, and M. Suzuki: Iron Steel Inst. Jpn. Int., 1997, vol. 37 (10), pp. 936-45.
Effect of Temperature on Cementite Formation by Reaction of Iron Ore with H2-CH4-Ar Gas JIANQIANG ZHANG, O. OSTROVSKI, and KIYONORI SUZUKI Temperature strongly affects cementite formation and its stability.[1,2,3] This article reports experimental results on cementite formation by reaction of iron ore with CH4-H2Ar gas in the temperature range 600 8C to 925 8C. Experiments on iron ore reduction/cementation were conducted in a laboratory fixed bed reactor. Gas mixture was prepared from purified methane, hydrogen, and argon (35 vol pct CH4, 55 vol pct H2, and 10 vol pct Ar). The total gas flow rate was maintained at 1000 cm3/min. The size of iron ore (Mt Whaleback, Western Australian) was 0.35 to
JIANQIANG ZHANG, Ph.D. Student, and O. OSTROVSKI, Associate Professor, School of Materials Science and Engineering, and KIYONORI SUZUKI, ARC Postdoctoral Fellow, School of Physics, are with the University of New South Wales, NSW 2052, Australia. This article is based on a presentation made in the “Geoffrey Belton Memorial Symposium,” held in January 2000, in Sydney, Australia, under the joint sponsorship of ISS and TMS. VOLUME 31B, OCTOBER 2000—1139
Fig. 1—(a) through (g) Phases formed in the iron ore reduction/cementation process using Ar-CH4-H2 gas mixture (35 vol pc
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