非等温下でのCr_2O_3およびFe_2O_3の熱炭素還元(高温プロセス基盤技術)

概要

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An investigation of the reduction of Cr_2O_3 and Fe_20_3 by graphite was carried out using a nonisothermal gravimetric technique under an argon atmosphere, in a temperature range from 600 to 1973K. In the case of Cr_20_3-C system, the reduction reaction proceeds through two stages. At first, Cr_20_3 is reduced by graphite to form chromium carbide, and then the rest of Cr_20_3 by the chromium carbide. The activation energies of the reaction are evaluated from 270 to 293 kJ/mol in the first stage and from 327 to 359 kJ/mol in the second stage. Excess graphite addition increases the reduction degree, and chromium carbide is obtained. Magnesia addition delayed the reduction, while hematite addition accelerates it. In the case of Fe_20_3-C system, the reduction proceeds through three steps. In the first stage, Fe_20_3 is reduced by graphite to form Fe_30_4. In the second stage, Fe_3O_4 is reduced to form FeO. In the third stage, FeO is reduced to form Fe. The activation energies of the reaction are 504 kJ/mol in the first stage, 858 kJ/mol in the second stage and 243-312 kJ/mol in the third stage. Excess graphite addition increases the reduction degree.
社団法人日本鉄鋼協会の論文
2004-12-01