ABSTRACT Recycling NdFeB magnet scrap provides an alternative neodymium source with a substantially reduced environmental footprint compared to conventional mining and extraction. Because neodymium is readily oxidized in an oxygen‐containing atmosphere, its recovery as neodymium oxide becomes feasible. To elucidate the phase relations, thermodynamic modeling of the Nd 2 O 3 –FeO–Fe 2 O 3 –SiO 2 system was conducted using available phase diagram information. Invariant reactions within this system were experimentally examined by differential scanning calorimetry (DSC) to refine the thermodynamic assessment. The liquid oxide phase was modeled by the modified quasichemical model (MQM), while the ternary compound Nd 9.33‐ x Si 6‐ x Fe x O 26‐ δ was described through the compound energy formalism (CEF) model. Optimization of Gibbs energy expressions for both the liquid and solid phases ensured consistency with all reliable and experimentally verified phase equilibria data.
Wei et al. (Fri,) studied this question.