Thermodynamic Modeling of CaO-CaF2 and CaO-SiO2 Systems

Abstract

CaO-CaF2-SiO2 system is a base system for commercial mould fluxes. Thermodynamic properties of CaOCaF2-SiO2 are essential for understanding the properties of mould fluxes and developing new mould fluxes. Thermodynamics of two sub-binary systems CaO-CaF2 and CaOSiO2 were modeled in the present work. A thermodynamic model for description of liquid slag presented by Björkvall et al. was extended to incorporate fluorine ion into model framework. The activities of components in CaO-CaF2 and CaO-SiO2 were calculated and good agreements between experimental and calculated activities were achieved. Phase diagrams for CaO-CaF2 and CaO-SiO2 systems were also well reproduced by the present calculation.