Temperature Dependence and Prediction of Density of Alkali Silicate Slag Melts

Abstract

We measured the density of eight types of molten alkali silicate slag within the range of 1673–1823 K using the Archimedean double-bob method. The melt density of binary alkaline silicate glass linearly increased with a decrease in temperature. The temperature coefficient of the density ranged from −21.5 to −13.2 × 10⁻⁵ g·cm⁻³·K⁻¹, and its order corresponded to the order of the ionic radii of the alkali oxide components. We applied Doolittle’s free volume theory by combining the reported values of melt viscosity with the measured densities and volume expansion coefficients of melts and glass solids to propose an equation for predicting melt density from slag composition and temperature. Melt densities in the range of 1273–1823 K were predicted and compared with experimental values.