Newly developed method for determining SiO2 activity of the silicate slags equilibrated with molten silicon alloys

Abstract

In the determination of activities of components other than SiO2 for the CaO-SiO2-AlO1.5-MgO slags equilibrated with molten Si alloys, activities of SiO2 in the slags are required and their accuracy will considerably affect the results. For the CaO-SiO2, CaO-SiO2-AlO1.5 and CaO-SiO2-MgO slags, the activities of SiO2 were obtained from the distribution of each element between slags and metals, and each thermodynamic property in molten Si alloys at 1 823 and 1 873 K using a newly developed method with the Gibbs-Duhem equation. The data obtained in the present research were compared with those reported by other investigators, and showed reasonable agreement in wide slag composition ranges. These activity data of SiO2 will be employed in the subsequent determination of other component activities for the binary and ternary slag systems concerned.