Accurate Density Calculation for Molten Slags in SiO₂–Al₂O₃–CaO–MgO Systems

Abstract

A density calculation model for molten slags in SiO₂–Al₂O₃–CaO–MgO system and its subsystems was established in this work, based on constant thermal expansion coefficients and composition-dependent excess molar volume. The model was calibrated by 909 density measurements in unary, binary, ternary and quaternary systems. Current model calculates the density with remarkable relative average error of 1.62% and overall absolute error of 56 kg/m³. The temperature dependence of molar volume was found to be linear within studied composition and temperature ranges. The temperature and composition dependences of unary to quaternary systems were plotted using current model. It reveals that the densities always decrease with increasing SiO₂ content. On a mass percent basis, substitution of SiO₂ by Al₂O₃ will cause an obvious increase in density; whereas substitution of CaO by MgO will result in a slight increase in density.