Thermodynamic Models of Liquid Silicates

Abstract

Abstract The development of structure-based thermodynamic models of binary silicates, which has occurred since the publications of Toop and Samis (1962) and Masson (1965), is reviewed. The various approaches used in the construction of these models include consideration of generalized polymerization-depolymerization equilibria involving the three forms of oxygen occurring in silicate melts and involving specificequilibria among discrete chain silicate ions and free oxygen ions, the application of the principles of polymer theory to calculation of the most probable distribution of branching chain silicate ions, calculation of the mixing properties by statistical mechanics. Monte Carlo minimization of free energy, and statistical approaches which consider the distribution of silicon and oxygen in quasi-lattices.The various models are examined and compared. Direct comparison is facilitated by the fact that, in the construction of each of the models, the free energy change for the depolymerization reaction O°...