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

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Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2021-12
Major/Subject
Mcode
Degree programme
Language
en
Pages
18
Series
Minerals, Volume 11, issue 12
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.
Description
Funding Information: Acknowledgments: Authors would like to thank the Wroclaw Research Center EIT+ for the financial support. The work was also co-financed by statutory activity subsidy from the Polish Ministry of Science and Higher Education for the Faculty of Chemistry of Wroclaw University of Science and Technology. Funding Information: This work was supported by Wroclaw Research Center EIT+ within the project ?The Application of Nanotechnology in Advanced Materials?NanoMat? (POIG 01.01.02-02-002/08). Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
Keywords
Extractive metallurgy, Rare earth elements, Recycling, Urban mining
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Citation
Klemettinen , A , Żak , A , Chojnacka , I , Matuska , S , Leśniewicz , A , Wełna , M , Adamski , Z , Klemettinen , L & Rycerz , L 2021 , ' Leaching of rare earth elements from NdFeB magnets without mechanical pretreatment by sulfuric (H 2 SO 4 ) and hydrochloric (HCl) acids ' , Minerals , vol. 11 , no. 12 , 1374 . https://doi.org/10.3390/min11121374