Effect of Gas Composition on the Carbothermic Reduction of Manganese Oxide

Abstract

This paper examines the reduction of pure MnO, Groote Eylandt (Northern Australia) manganese ore, siliceous manganese fines and ferromanganese slag by graphite. Reduction was conducted in the stagnant atmosphere of argon, Ar-CO gas of varying composition and helium. The rate and extent of reduction were determined by thermo-gravimetric analysis and by monitoring CO and CO₂ concentrations in the gas phase. The rate of MnO reduction in Ar-CO gas increased with decreasing CO partial pressure. Reduction in helium was faster than in argon. Under given experimental conditions (stagnant gas atmosphere) the reduction rate was mix-controlled by CO mass transfer in the gas phase and chemical reaction.