Thermodynamic Activity of SiO₂ in CaO–SiO₂–Al₂O₃–MnO–MgO System Molten Slags

Abstract

To understand the thermodynamic characteristics of the reaction between Al and SiO₂ during the continuous casting process of the high-aluminum steel, the activity coefficients of SiO₂ and MnO in molten slags of (18–43%) CaO-(33–64%) SiO₂-(9–21%) Al₂O₃-(2–3%) MgO-(<2.4%) MnO were measured at 1400°C, 1450°C and 1500°C by the experiments of the Si and Mn equilibrium between liquid copper and molten slag in the graphite crucible under the mixed gas atmosphere of CO and Ar. The effects of SiO₂, Al₂O₃, the basicity, the radio of CaO/Al₂O₃ and the temperature on the activity coefficients of SiO₂ and MnO in molten slag were discussed. The quadratic regression relationships among the activity coefficient of SiO₂ or MnO, the concentration of component, the basicity and the temperature were investigated by the regression analysis method.