Thermodynamic Assessment of CaO-Al2O3-Fe2O3 System.

The CaO-Al2O3-Fe2O3 system is widely encountered in cement production, iron ore sintering, metallurgical slags, and refractory materials. A thermodynamic assessment of the CaO-Fe2O3 and CaO-Al2O3-Fe2O3 systems was carried out in this study based on the CALculation of PHAse Diagrams (CALPHAD) method. The liquid was modeled using the ionic two-sublattice model, expressed as (Ca+2, Al+3, Fe+2) P (O-2, AlO1.5, FeO1.5, Va, O) Q. The Compound Energy Formalism (CEF) was adopted to describe compounds and solid solutions. A self-consistent thermodynamic assessment of the CaO-Fe2O3 and CaO-Al2O3-Fe2O3 systems was achieved, enabling accurate reproduction of phase equilibrium and thermodynamic data. The obtained thermodynamic description provides a useful foundation for the design, optimization, and processing of refractory materials.