New technology for lanthanide recovery from spent Nd-Fe-B magnets

Abstract

A new technology, representing a complete process of recovery of rare earth elements from neodymium-iron-boron permanent magnets scrap by acid dissolution and liquid-liquid extraction, is proposed. This technology is based on basic research of individual process steps. A hydrometallurgical process containing acid leaching with subsequent two-step solvent extraction on a counter current multistage extraction column is employed to separate iron from lanthanides, re-extract lanthanides in the form of sulphates, precipitate as oxalates, and finally calcinate to a pure state as didymium oxide (praseodymium + neodymium) and dysprosium oxide.

Keywords

• Nd-Fe-B magnets
• Rare-earth elements recovery
• Liquid-solid reaction