Plasma reduction of a low grade chromite ore.

摘要

The effect of dc plasma heating with or without induction during the smelting reduction of a low grade Bird River chromite concentrate analyzing about 27% Cr{dollar}sb2{dollar}O{dollar}sb3{dollar}, 33% FeO, 10% SiO{dollar}sb2{dollar}, 11% Al{dollar}sb2{dollar}O{dollar}sb3{dollar} and 10% MgO has been investigated. The major experimental variables were the plasma polarity, power source and slag chemistry. High sulphur containing anthracite was used as the reductant.; The use of plasma in combination with induction heating was found to give the best results compared to plasma heating only. Energy transfer efficiency to the reactants was better with negative polarity electrode plasma. The reduction kinetics were significantly enhanced by application of plasma with induction. Although the rate of reduction was higher for reverse polarity plasma, heat transfer to the reactants was poor.; Kinetics of the reduction were favorable with an increase in CaO+MgO/SiO{dollar}sb2{dollar}. Above CaO+MgO/SiO{dollar}sb2{dollar} ratios of 0.7, the effect of lime was not significant. Sulphur removal was excellent under both normal (negative electrode) and reverse positive electrode) plasma/induction conditions with sulphur levels below 0.02% being obtained. The slag acted as a transfer medium of sulphur from metal to the gas phase.; The results of the present study demonstrate the feasibility of a stainless steel route with process and energy savings.