A KINETIC-STUDY ON CHROMITE ORE SMELTING REDUCTION

Experiments on the smelting reduction of chromite ore in a 1-kg middle frequency induction furnace showed that the reduction is controlled by the mass transfer of chromium oxide dissolved in the slag. The dissolution of chromite particles into the liquid slag has little effect on the reduction rate. A decrease in the initial slag basicity (CaO/SiO2) from 1.5 to 1.0 decreases the reduction rate constant by about 50%. It also increases the chromium partition ratio between the final slag and the metal bath by a factor of about 7. Addition of 5% calcium fluoride to the initial slag increases the reduction rate constant by a factor of 4. The effect of temperature on the reduction rate is significant. The apparent activation energy is about 250 kJ/mol.