Oxidation-Enhanced Evaporation in High-Carbon Ferromanganese

Abstract

Thermal fume formation is a problem in manganese ferroalloy production and the metal production industry at large. A better understanding of the mechanisms of fume formation and the operational parameters affecting the fume formation rate may help in reducing and managing fuming. This paper aims to investigate the effects of oxygen content and gas flow rate on the fuming rate and fume particulate properties for liquid high-carbon ferromanganese. The fuming rates were attained experimentally by measuring the fume flux with respect to oxygen content and gas velocity above the metal melt. The generated fumes were also characterized in terms of particle size and element distribution between fume and melt. The fuming rates were found to steadily increase with increasing oxygen content and flow rate of the gas up to a point where the curve flattens, following theoretical predictions. However, the highest flux values measured were above the theoretical limitations of the evaporation flux in vacuo given the alloy bulk composition. It is hypothesized that the high rate of fuming is caused by an increased manganese activity at the alloy surface due to local decarburization of the alloy in contact with the oxidizing gas. Graphical Abstract