IMMISCIBLE SILICATE LIQUIDS IN THE CAO-SIO2-TIO2-AL2O3 SYSTEM

Compositions of coexisting liquids in the CaO-SiO2-TiO2-Al2O3 system a t 1600 degrees C have been determined. In the Al-free ternary system, the miscibility gap is modelled in detail with weighted extrapolation of binary excess Gibbs free energy terms. Addition of few wt% Al2O3 re duces dramatically the extent and consolute temperature of the solvus. Extrapolations of the CaO-SiO2-TiO2 model parameters to the Al-bearin g system without additional corrections disagree with experiments. How ever, possible procedures for the expanded extrapolation in the four c omponent system are discussed.