Physicochemical model for predicting molten glass density

Models have been developed since the 1970s to predict the composition- and temperature-dependent density of silicate melts in which the molten glass is considered as a mixture of virtually ideal solutions. Published data were compiled to set bounds on the partial volumes of each constituent oxide of radioactive waste containment glass. A model based on the data is proposed to predict the density of complex molten borosilicate glass formulations between 900 and 1300 °C. The model is limited to compositions with silica concentrations between 40 and 80 mol%, alkali oxide concentrations between 5 and 50 mol%, and SiO₂/B₂O₃ molar ratios exceeding 0.9. Within this composition range the model is capable of reproducing the experimental data within 4%. One application of this approach is to construct an interpolation equation suitable for use in models simulating the thermal, rheological, electrical, and magnetic conditions of vitrification processes.