Reduction of chromium oxide from slags

Experimental and theoretical work were performed to estimate the effect of slag basicity and amount of reducing agents on the reduction of chromium oxide from the slag which interacted with molten steel at 1,600 °C. The slag system contained CaO, MgO, SiO 2 , CaF 2 and Cr 2 O 3 together with Fe-alloys (Fe-Si and Fe-Si-Mg). The CaF 2 and MgO contents in the slags were 10 mass % each; Cr 2 O 3 was 25%. The amount of the ferroalloys ranged from 12.5 to 50 g per 100 g of slag. The (CaO+MgO)/SiO 2 ratio was held at 1 and 2. The Cr yield was determined using both Fe-alloys as reducing agents. Some estimations were made to determine the theoretical effect of temperature, slag basicity, (CaO+MgO)/SiO 2 , and amount of reducing agents in the slag on the chromium recovery. The FACT (Facility for the Analysis of Chemical Thermodynamics) computational package is used to determine the equilibrium between the slag and molten steel.