Effect of Slag Properties on Reduction Rate of Chromium Oxide in Cr₂O₃ Containing Slag by Carbon in Steel

Abstract

The experiments were performed using a small-scale furnace in order to improve the reduction rate of chromium oxide in Cr₂O₃ containing slag by carbon in steel. As a result of the investigation of the experiments by SOLGASMIX, the following points were clarified:
1) The reduction rate of chromium oxide in slag was improved by lowering the basicity of the slag or by adding Al₂O₃ or CaF₂. This improvement was caused by the increase of liquid phase fraction of the slag.
2) The liquid fraction of the slag was related to the increase of the mass transfer coefficient and/or the effective reaction area of reaction.
3) The dissolution of MgO was accelerated greatly by lowering the basicity or by adding CaF₂. This phenomenon was caused by the increase of MgO solubility in the slag.
4) The optimum composition of slag is (Al₂O₃)=15% and CaO/SiO₂=2.5 from the viewpoint of the compatibility of the improvement of reduction rate of chromium oxide and the prevention of the dissolution of the refractories.