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Direct Recycling of Nd–Fe–B Magnets Based on the Recovery of Nd 2 Fe 14 B Grains by Acid‐free Electrochemical Etching
Author(s) -
Xu Xuan,
Sturm Saso,
Samardzija Zoran,
Vidmar Janja,
Scancar Janez,
Rozman Kristina Zuzek
Publication year - 2019
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201902342
Subject(s) - magnet , neodymium , materials science , etching (microfabrication) , anode , metal , rare earth , matrix (chemical analysis) , metallurgy , analytical chemistry (journal) , nuclear chemistry , nanotechnology , chemistry , composite material , electrode , electrical engineering , laser , physics , optics , layer (electronics) , chromatography , engineering
Recycling of end‐of‐life Nd–Fe–B magnets is an important strategy for reducing the environmental dangers associated with rare‐earth mining and overcoming the supply risks associated with the rare‐earth elements. In this study, a novel concept for recycling of sintered Nd–Fe–B magnets by directly recovering the matrix Nd 2 Fe 14 B grains is presented. The procedure is based on the anodic etching of sintered Nd–Fe–B magnets in a nonaqueous dimethylformamide (DMF)/0.3 mol L −1 FeCl 2 bath. Selective recovery of Nd 2 Fe 14 B grains was realized within the applied current density <5 mA cm −2 based on the etching priority of phases: metallic Nd > intergranular NdFe 4 B 4 > matrix Nd 2 Fe 14 B. The total energy consumption of the proposed recycling route is estimated to be 2.99 kWh kg −1 , which is comparable to the state‐of‐the‐art methods. However, the proposed recycling route is currently the only procedure that enables repeated recycling of sintered Nd–Fe–B magnets in a closed‐loop system.