Efficient recovery of rare earth elements from high-temperature metallurgical processes requires a comprehensive understanding of phase equilibria in oxide-based slags. A thermodynamic assessment of the Nd 2 O 3 -FeO x -CaO ternary system was constructed based on existing phase diagram data, and on the invariant reactions which analyzed by Differential Scanning Calorimetry (DSC) in this work. The Gibbs energy of the liquid phase in the Nd 2 O 3 -FeO x -CaO ternary system was modeled using the Modified Quasichemical Model (MQM). The perovskite-type ternary compound Nd 1-x Ca x FeO 3-δ was modeled with the Compound Energy Formalism (CEF) model. The optimized phase diagram of the Nd 2 O 3 -FeO x -CaO ternary system is in good agreement with the experimental data.
Wei et al. (Thu,) studied this question.