Critical Evaluation and Thermodynamic Optimization of the Na2O-FeO-Fe2O3 System

A complete literature review, critical evaluation, and thermodynamic optimization of experimental phase diagrams and thermodynamic properties of the Na 2 O-FeO-Fe 2 O 3 system were performed at 1 bar total pressure. A set of optimized model parameters obtained for all phases present in this system reproduces available and reliable thermodynamic properties and phase equilibria within experimental error limits from 298 K (25 °C) to above liquidus temperatures for all compositions and oxygen partial pressures from metallic saturation to 1 atm. The liquid phase was modeled based on the Modified Quasichemical Model by considering the possible formation of NaFeO 2 associate in the liquid state. Complicated subsolidus phase relations depending on the oxygen partial pressure and temperature were elucidated, and discrepancies among experimental data were resolved.