The Al₂O₃-Fe₂O₃-FeO system is an important subsystem in the solid wastes and knowledge of its phase equilibria is of great significance for the phase transformation and reconstruction of mineral phases in the process of solid waste resource utilization [1]. Motivated by developing a thermodynamic database of the multicomponent system with compatible ionic two-sublattice liquid model, a reassessment of the Al₂O₃-Fe₂O₃-FeO system was conducted through the CALPHAD method. All relevant experimental data in the literature were critically reviewed. The sublattice model based on the compound energy formalism was applied for the solid solution phases to describe the homogeneity range and the distribution of cations in different lattice sites. The liquid phase was described by the ionic two-sublattice liquid model as (Al⁺³, Fe⁺²)_P(AlO₂^-1, FeO_1.5, O^-2, VA)Q. The species AlO₂^-1 was introduced to model pure liquid Al₂O₃, ensuring compatibility with the latest thermodynamic optimizations of the Al₂O₃-CaO-SiO₂ [2] and the Al₂O₃-MgO-SiO₂ [3] systems. A new self-consistent set of thermodynamic parameters for the Al₂O₃-Fe₂O₃-FeO system was obtained, and comprehensive comparisons between the calculations and experimental data indicate that the present thermodynamic description is capable of reproducing the experimental data reasonably. The present thermodynamic calculations demonstrate several noticeable improvements in comparison with previous calculations. This research holds significant implications for the recycling and utilization of industrial solid wastes.

References

[1] S. Wang, F. Gao, B. Li, Y. Liu, T. Deng, Y. Zhang, W. Chen, Constr. Build. Mater., (2024), 418, 135357.

[2] H. Mao, M. Hillert, M. Selleby, B. Sundman, J. Am. Ceram. Soc., (2006), 89, 298-308.

[3] H. Mao, O. Fabrichnaya, M. Selleby, B. Sundman, J. Mater. Res., (2005), 20, 975-986.