Comparison of three excess Gibbs energy models for the CaO-Al<inf>2</inf>O<inf>3</inf> and CaO-SiO<inf>2</inf> solid solutions

Abstract

The paper suggests an application of the real solution model for prediction of the Gibbs free energy values of the CaO-Al2O3 and CaO-SiO2 systems. Particularly, the importance of the excess Gibbs free energy has been emphasized. The assessment of the excess Gibbs free energy has been performed by applying three models- two two- parameter models comparatively with one three- parameter model. One series of the ideal Gibbs free energies has been compared with three series of the real Gibbs free energies (for each analyzed system in an interval: 298-1500 K). The differences between `ideal' and `real' energies have been expressed as absolute and relative deviations. Also, an average absolute deviation and average relative deviation, for each particular system, have been calculated. The concept of the real solution proved successful, while the three- parameter model, for the excess Gibbs free energy, gave the best result.