The Solubility of the Chromite in MgO-Al₂O₃-SiO₂-CaO Melts at 1 600°C in Air

Abstract

The solubility of the picrochromite MgO·Cr₂O₃ into MgO-Al₂O₃-SiO₂ melts were measured at 1 600°C in air, to understand the bahavior of smelting reduction of chromite ore. The solubility of picrochromite were 1.1-4.5wt% Cr₂O₃ in MgO-SiO₂-Cr₂O₃ melts. In MgO-CaO melts, they were as much as 40-55wt% CrO_x, although more than 50% of chromium exists as Cr⁶⁺ in the high CaO and low MgO region. The solubility of the picrochromite increased from 0.2-0.8wt% Cr₂O₃ to 0.5-2.6wt% Cr₂O₃ by adding CaO to the MgO-Al₂O₃-SiO₂ melts. For Al₂O₃ containing melts, the chromium in the chromite MgO·Cr₂O₃ was substituted by aluminum in proportion to Al₂O₃ content in the melt.