Oxidation behavior and kinetics of Al2O3-SiC-SiO2-C refractories in CO2 atmosphere

Al₂O₃-SiC-SiO₂-C refractories are widely used as blast furnace hearth lining but have low oxidation resistance in the presence of CO₂. Carbon composite brick is a newly developed Al₂O₃-SiC-SiO₂-C refractory that may function better in the blast furnace hearth due to improved erosion-resistance and high thermal conductivity. In this study, the oxidation behavior and kinetics of carbon composite brick, carbon brick, and corundum brick were investigated in CO₂ atmosphere. The results show the oxidation resistance of carbon composite brick was better than that of carbon brick but worse than that of corundum brick. SiC functions as an antioxidant to play an important role in the oxidation process. For carbon composite brick, the oxidation activation energy was 141.72 kJ/mol at the step controlled by the interface reaction and 161.24 kJ/mol at the step controlled by gas diffusion. Carbon composite brick exhibits improved thermal conductivity and oxidation resistance relative to carbon brick and corundum brick that should allow improved performance in blast furnace hearth lining.