Abstract: A novel thermodynamic model-the molecular interaction volume model (MIVM) which can be reduced to the Flory-Huggins equation of polymer solution was employed for the prediction of component activities in the ternary molten aluminosilicate slag CaO-Al2O3-SiO2 at different temperatures. The results show that the predicted values of activity of CaO, Al2O3 and SiO2 are in reasonably agreement with experimental data in some ranges of their concentrations which are about x1<0.25 for CaO, x2=0.05–0.55 for Al2O3 and x3=0.03–0.85 for SiO2. This further shows that MIVM requires only two binary parameters for each sub-binary system to predict activities of all components in a multicomponent solution and is the superior alternative in a molten slag.

Key words: Activity, Prediction, Molten aluminosilicate slag, Molecular interaction volume model