The 21st ESICMM Seminar

  Recycling of Rare Earth (RE) elements from permanent magnets becomes a necessity to ensure a sound usage of RE resources and a sufficient RE supply to meet the growing demand for low-CO₂ emission technologies. Permanent magnets are composed of Nd₂Fe₁₄B alloy with small additions of Pr, Tb, Dy, Co, Cu, Ni, etc. A possible recycling route consists in the liquid-solid extraction process, in which Nd is dissolved in liquid Mg, whereas Fe and B are essentially insoluble in the solvent. Other metallic solvents, such as Ag, Si, Ti, Pb, Sn, etc., are also possible. As part of a research project to develop REE recycling technology, a large thermodynamic database for REE containing systems was developed.
  In the thermodynamic database development, many discrepancies in existing experimental data and lack of experimental data were resolved by systematic analysis of all available REE systems simultaneously.  In the present study, the energetics of REE-X binary systems where X = Mg, Al, Zn, Si, Sn, Mn, Pb, Fe, Co, Ni, etc. will be presented, and a strategy how we can overcome the lack of experimental data and resolve the discrepancies of existing experimental data will be discussed. Then, a large thermodynamic database for Nd permanent magnet (Fe-Nd-B-Dy-Ce) recycling will be presented with application examples.