還元褐鉄鉱の CO-H_2-H_2S 混合ガスによる流動層中での炭化挙動 : 還元温度と炭化温度の影響(新鉄源・リサイクル)(<特集>製銑プロセスの機能強化と新展開)

概要

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Iron ore particles of a limonite were completely reduced with H_2 at temperatures from 973 to 1273K in a laboratory scale fluidized bed. Then, at temperatures from 873 to 1073K, mainly at 973K, the reduced iron was exposed to H_2-H_2S mixtures (sulfur activity, a_S=0.5 or 0.1) for 3.6 ks and carbidized with 80%CO-H_2-H_2S mixtures at the atmospheric pressure. The integrated rate equation for first-order reaction, -ln(1-f_θ)=g(p_i, T)t ; can be fitted very well to the carbidization curves. It is found that the carburization rate per reduced iron unit surface area g(p_i, T)/a^0_p slightly increases with increasing the reduction temperature. The value of g(p_i, T)/a^0_p decreases with increasing the specific surface area of reduced iron, a^0_p, which increases with decreasing the reduction temperature, and increases with increasing the carbidization temperature. The specific surface area and sulfur content of the reduced iron does not largely change during most period of the carbidization, but both of them start simultaneously to increase just after free carbon deposition starts at the latest stage for the carbidization of reduced iron at 973K. The best temperatures for producing iron carbide are concluded to be 1123-1173K for reducing limonite iron ore and 973K for carbidizing the reduced iron.
社団法人日本鉄鋼協会の論文
2001-05-01