Direct Recycling of Nd-Fe-B Magnets Based on the Recovery of Nd₂ Fe₁₄ B Grains by Acid-free Electrochemical Etching.

ABSTRACT: 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 Nd₂ Fe₁₄ 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 FeCl₂ bath. Selective recovery of Nd₂ Fe₁₄ B grains was realized within the applied current density <5?mA?cm^-2 based on the etching priority of phases: metallic Nd > intergranular NdFe₄ B₄ > matrix Nd₂ Fe₁₄ 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.

SUBMITTER: Xu X 

PROVIDER: S-EPMC6916163 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature