Recovery of Rare Earth Elements from Spent NdFeB-Magnets: Separation of Iron through Reductive Smelting of the Oxidized Material (Second Part)


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Chung H., Stopic S., Emil-Kaya E., Gürmen S., Friedrich B.

METALS, vol.12, no.10, 2022 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 12 Issue: 10
  • Publication Date: 2022
  • Doi Number: 10.3390/met12101615
  • Journal Name: METALS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Aerospace Database, Applied Science & Technology Source, Chemical Abstracts Core, Communication Abstracts, INSPEC, Metadex, Directory of Open Access Journals, Civil Engineering Abstracts
  • Keywords: recycling, smelting, oxidation, rare earth elements, magnets, PRETREATMENT, WIND, ND
  • Istanbul Technical University Affiliated: Yes

Abstract

This paper proposes a pyrometallurgical recycling method for end-of-life NdFeB magnets by oxidizing them in air and subsequently smelting them. The smelting process enabled the recovery of rare earth elements (REEs), producing a new reach concentrate separating the iron as a metallic phase. From the products of smelting, the metallic phase showed a maximum Fe content of 92.3 wt.%, while the slag phase showed a maximum total REE (Nd, Pr, and Dy) content of 47.47 wt.%, both at a smelting temperature of 1500 degrees C. ICE-OES and XRD analysis were conducted on both phases, and results showed that the metal phase consists mainly of Fe and Fe3C while the slag phase consists of the RE-oxides, leftover Fe2O3, and a mixture of Fe6Nd4. The obtained slag concentrate based on the oxides of rare earth elements is suitable for further pyrometallurgical or hydrometallurgical treatment in order to obtain rare earth elements.