Densities and Surface Tensions of Melts in the System CaF₂-CaO-SiO₂

Abstract

Densities and surface tensions of CaF₂-CaO-SiO₂ melts were measured by the Archimedean method and the maximum bubble pressure method, respectively. From the measured densities, the molar volume was computed for the following binary systems; CaF₂-CaO, CaF₂-3CaO·SiO₂, CaF₂-2CaO·SiO₂, and CaF₂-3CaO₂·SiO₂. For the systems, the molar volume obeyed the simple additive law on volume and it suggests that calcium fluoride in the melts behaves as a diluent. On the other hand, the surface tension for the binary systems changed approximately in accordance with the Guggenheim's equation for the regular solution. From the results, the iso-density curves and the iso-surface tension curves were proposed for the CaF₂-CaO-SiO₂ ternary melts having the ratio, CaO/SiO₂ > 1.5 at 1 550C°.