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

In the determination of activities of components other than SiO2 for the Ca O-SiO2-AlO1.5-MgO slags equilibrated with molten Si alloys, activities of S iO2 in the slags are required and their accuracy will considerably affect t he results. For the CaO-SiO2, CaO-SiO2-AlO1.5 and CaO-SiO2-MgO slags, the a ctivities of SiO2 were obtained from the distribution of each element betwe en 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 equa tion. The data obtained in the present research were compared with those re ported by other investigators, and showed reasonable agreement in wide slag composition ranges. These activity data of SiO2 will be employed in the su bsequent determination of other component activities for the binary and ter nary slag systems concerned.