The Phase Relations of the CaO-MnO-SiO₂ System in Connection with the Smelting Reduction of Manganese Ore

Abstract

The phase relations of the CaO-MnO-SiO₂ system at 1400°C have been investigated in connection with the smelting reduction of manganese ore in a basic oxygen furnace by employing a chemical equilibration technique. Namely, a molten Cu-Mn alloy was separately equilibrated with a CaO-MnO solid solution or a CaO-MnO-SiO₂ melt. It has been found that the solid in conjugation with the molten phase is nearly pure MnO regardless of the composition of the latter. The CaO-MnO solid solution negatively deviates from an ideal solution. From these findings, the dissolution behavior of manganese ore into a molten slag has been discussed.