Analysis and prediction of the viscosity of the SiO2-Al2O3-CaO ternary system in completely molten state

Based on the theory of random network model, the effects on the structure role in the SiO2-Al2O3-CaO ternary system for each component was analysed. The theory of random network model considers the amphoteric role of Al2O3in the silicate system, and its strong preference for tetrahedral coordination with its charge deficit being compensated by alkaline earth metal cations, Mn+etc. For studying the varied viscosity with the ratio of n (CaO)/[n (CaO) + n (Al2O3)] in the SiO2-Al2O3-CaO ternary system, the relationship between viscosity and component with the ratio of that typically in the range of 0.4-0.6 was investigated. The results show that, with the ratio of n (CaO)/[n (CaO) + n (Al2O3)] increasing from 0.4-0.6, the viscosity of the silicate melts increases slowly at First, and then decreases fiercely, but when that was at 0.5, the viscosity of silicate melts never reaches the maximum. Ground on the properties of fluid, the mathematical model for SiO2-Al2O3-CaO ternary system in completely molten state was established, which was better than the conventional Urbain model, and good agreement between experimental value and prediction one was obtained.