Corrosion resistance of MgO–C refractory to smelting reduction slag containing titania

Abstract

Interactions between smelting reduction slags containing titania (0·2-20 wt-%TiO₂) and MgO-C refractories have been investigated by stationary immersion and rotary immersion at temperatures of 1773-1923 K. The relationship between the concentration of TiO₂ in the slag and the corrosion rate of the refractories, the effects of slag basicity (CaO/SiO₂), and the effect of the temperature of the molten bath on the corrosion rate were examined. Increasing the TiO₂ concentration in the slag caused an increase in the corrosion rate of the MgO-C refractories. The corrosion rate also increased when the temperature was increased. Increasing the basicity of the acid slag decreased the corrosion rate, but this effect was not evident when the basicity of slag exceeded 1·0. The corrosion mechanism of MgO-C refractories in smelting reduction melts containing titania involves the oxidation of graphitic carbon by TiO₂ and the formation of a deterioration layer containing Ti and TiC, together with the reaction of matrix MgO with slag to form MgAl₂O₄, MgCaSiO₄, and MgSiO₃.