Activity measurement of CaO-SiO2-AlO1.5MgO slags equilibrated with molten silicon alloys

The activities of components in the CaO-SiO2-AlO1.5-MgO slags at 1 823 and 1 873 K were directly measured by equilibrating the slags with Si based all oys. For the CaO-SiO2, CaO-SiO2-AlO1.5 and CaO-SiO2-MgO systems, thermodynamic p roperties of Si based alloys and the activity data of SiO2 obtained from th e distribution of each element between slags and the alloys in the previous paper were used to derive the activities of AlO1.5, CaO and MgO. For the C aO-SiO2-AlO1.5-MgO quaternary system, the activities of components other th an SiO2 on the 10 mass% MgO plane were determined at 1 873 K by employing t he SiO2 activities available in the literature. Accordingly, it was confirmed that the activities of components other than SiO2 in multi-component silicate slag systems can be determined by this tec hnique as long as the activity datum of at least one component in the syste ms is available.