Catalytic Effect of Iron Oxide on the Combustion of Carbonaceous Materials in Mold Flux for Continuous Casting

The reverse gradient distributions of temperature and oxygen concentration in the three-layers structure of mold flux at the upper part of the continuous casting mold are easy to cause the insufficient burning of carbonaceous materials of mold flux, resulting in the generation of carbon-rich layer and too slow melting of mold flux. Through a melting behavior experiment, the addition of a small amount of iron oxide into mold flux was found to promote the melting of mold flux significantly. The calculations of the comprehensive combustion index and combustion kinetic based on thermogravimetric experiments proved that iron oxide facilitated the burning of carbonaceous materials and the melting of mold flux by decreasing the activation energy of the combustion reaction. The catalytic effect of iron oxide on the combustion of carbonaceous materials of mold flux in the high-temperature and oxygen-poor zone of the slag layer was realized through the oxidation–reduction cycle reactions of iron oxides with different valence states. The above findings provide a brand new approach to solve the carbon-rich predicament of mold flux caused by the incomplete burning of carbonaceous materials.