日本金属学会誌

J. Japan Inst. Metals, Vol. 48, No. 3 (1984),
pp. 285-292

Rates of MnO Reduction from CaO-Al2O3 Slags by Solid Carbon

Toshio Shimoo1, Shigeru Ando1 and Hiroshi Kimura1

1College of Engineering, University of Osaka Prefecture, Sakai

Abstract:

The rate of MnO reduction from CaO-Al2O3 slag melted in a graphite crucible as a reductant has been determined. At temperatures between 1823 and 1973 K and under Ar atmosphere, the mass loss was continuously measured by means of thermo-balance.
The mass balance indicated that most of the produced molten manganese was evaporated for slag initially containing MnO less than 8 mass%, and that the rate of MnO reduction was nearly equal to that of Mn evaporation. The reduction rate remained constant in the range of reduction degree from 10 to 60%. It was found that the reduction rate was markedly dependent on the wetting of slag on the graphite crucible wall. In the range of 1.062O3<1.26, the reaction was approximately of the first order in regard to the activity of MnO, and the activation energy for reduction was 397 kJ/mol. It was supposed that the reaction proceeded primarily by the direct reduction and the rate was controlled by chemical processes at the slag-graphite interface.


(Received 1983/08/22)

Keywords:

slag, graphite crucible, mass loss, thermo-balance, MnO reduction, manganese vapor, reaction mechanism, rate-determining step


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