高温域におけるFeCr2O4およびMgCr2O4の炭素還元

下尾 聰夫, 岡本 龍幸, 木村 弘

doi:10.2320/jinstmet1952.53.1_71

In relation to the smelting reduction of chromite ore, the mechanism of reduction of FeCr₂O₄ and MgCr₂O₄ with solid carbon was investigated at high temperatures from 1723 to 1923 K under an argon atmosphere. The rate of reduction was measured by means of thermogravimetry, and the formation of the reduction product was examined by microscopic observation. (1) With increase in particle size of FeCr₂O₄, the reduction rate decreased at low temperatures, but it was scarcely affected at high temperatures. During the reduction of the fine particle of FeCr₂O₄, the Fe-Cr-C alloy was formed around the graphite particle. In the case of the coarse particle, it was formed in the oxide. FeCr₂O₄ was essentially reduced by the combination of the gaseous reduction and the formation of Co, and at higher temperatures, the direct reduction by the carbon dissolved in the molten Fe-Cr-C alloy occurred simultaneously. The rate-determining step varied with the particle size of the samples and the experimental temperature. (2) When the particle size became extremely small, the reduction of MgCr₂O₄ was retarded as the result of the variation in the reaction mechanism. In the reduction of the fine particle of MgCr₂O₄, the graphite particle was coated with carbide. The rate determining step was the solid state diffusion through the cabide. The most of carbide was finely dispersed apart from the graphite particle at a low temperature, 1723 K. The reduction of the coarse particle of MgCr₂O₄ proceeded topochemically and was controled by the gas diffusion through the porous product layer.

高温域におけるFeCr<SUB>2</SUB>O<SUB>4</SUB>およびMgCr<SUB>2</SUB>O<SUB>4</SUB>の炭素還元

書誌事項

この論文をさがす

説明

収録刊行物

キーワード

詳細情報詳細情報について

書き出し

問題の指摘