Leaching of rare earth elements from NdFeB magnets without mechanical pretreatment by sulfuric (H2SO4) and hydrochloric (HCl) acids

Anna Klemettinen*, Andrzej Żak, Ida Chojnacka, Sabina Matuska, Anna Leśniewicz, Maja Wełna, Zbigniew Adamski, Lassi Klemettinen, Leszek Rycerz

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

11 Citations (Scopus)
50 Downloads (Pure)

Abstract

A simplified approach for rare earth elements leaching from NdFeB (neodymium-iron-boron) magnets was investigated. The possibility of simplifying the magnet recycling process by excluding grinding, milling and oxidative roasting unit operations was studied. Attempts to skip the demagnetization step were also conducted by using whole, non-demagnetized magnets in the leaching process. The presented experiments were conducted to optimize the operating conditions with respect to the leaching agent and its concentration, leaching time, leaching temperature and the form of the feed material. The use of hydrochloric and sulfuric acids as the leaching agents allowed selective leaching of NdFeB magnets to be achieved while leaving nickel, which is covering the magnets, in a solid state. The application of higher leaching temperatures (40 and 60 C for sulfuric acid and 40 C for hydrochloric acid) allowed us to shorten the leaching times. When using broken demagnetized magnets as the feed material, the resulting rare earth ion concentrations in the obtained solutions were significantly higher compared to using whole, non-demagnetized magnets.

Original languageEnglish
Article number1374
Number of pages18
JournalMinerals
Volume11
Issue number12
DOIs
Publication statusPublished - Dec 2021
MoE publication typeA1 Journal article-refereed

Keywords

  • Extractive metallurgy
  • Rare earth elements
  • Recycling
  • Urban mining

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