Corrosion resistance of MgO-ZrO2 Brick and MgO-Cr2O3 brick compared by rotating slag attacking method

An environment-friendly material MgO-ZrO2 brick which is hoped to substitute for MgO-Cr2O3 brick was investigated. The using effect of MgO-ZrO2 brick and MgO-Cr2O3 brick was compared by rotating slag attacking method which environment is similar to the environment in RH degasser. It indicates that the corrosion resistance performance of MgO-ZrO2 brick is better than that of MgO-Cr2O3 brick. Due to the effect of molten steel, slag and oxygen, Fe being oxidized to FeO or Fe2O3 at high temperature 1900K will produce volume expansion which results in MgO-Cr2O3 brick being cracked. At the same time, Cr2O3 will be decomposed to CrO3 gas, which will be evaporated seriously by the airflow and lead to MgO-Cr2O3 brick structural loosen and deteriorated, ultimately. While the activity of oxygen dissolved molten steel is extremely low and ZrO2 is stable in the rotary kiln at 1900K. Furthermore, ZrO2 will react rapidly with CaO and its product CaZrO3 will form dense layer which prevents MgO-ZrO2 brick from being corroded. Therefore, trial production of MgO-ZrO2 brick applied for RH degasser is recommended.