Leaching Behavior of Rare Earth Elements from Waste NdFeB Magnets Utilizing Deep Eutectic Solvents

Rina Kim; Seojin Heo; Ho-Sung Yoon; Chul-Joo Kim; Sugyeong Lee; Kyeong Woo Chung

doi:10.32390/ksmer.2023.60.5.284

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2023 Vol.60, Issue 5S Preview Page Next Page

Research Paper (Special Issue)

Leaching Behavior of Rare Earth Elements from Waste NdFeB Magnets Utilizing Deep Eutectic Solvents 공융용매를 활용한 폐 NdFeB자석으로부터 희토류 침출 거동

31 October 2023. pp. 284-291

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Abstract

The leaching behavior of a rare earth element, neodymium, from waste NdFeB magnets using deep eutectic solvents (DESs) was investigated. Eight different DESs were prepared for leaching tests. The basic tests were conducted on Nd and Fe compounds, Nd₂O₃, Fe, and Fe₂O₃. Using GUC-LAC, ChCl-LAC, and EG-MA, Nd₂O₃ was leached by 64–100%. With the three DESs, Fe exhibited a leaching efficiency of over 94% in all DESs, while that of Fe₂O₃ remained low at <7%. Based on the results, leaching tests were conducted on NdFeB magnets with and without oxidative roasting. The leaching efficiencies of Nd and Fe significantly decreased after the roasting, at 27% and 4.7%, respectively. This was attributed to the formation of NdFeO₃ during the roasting. Therefore, to selectively recover Nd from NdFeB magnets, the application of the appropriate pre-treatment method is necessary, prioritizing the separation of individual oxides to Nd₂O₃ and Fe₂O₃.

Keywords

rare earth elements

NdFeB magnet

deep eutectic solvents (DESs)

leaching

recycling

폐 NdFeB 자석으로부터 공융용매를 활용한 희토류 침출 거동 연구를 수행하였다. 8개의 공융용매를 제조하여 Nd₂O₃, Fe, Fe₂O₃ 등 Nd, Fe 화합물에 대한 기초 침출 거동 실험을 우선 수행하였다. Nd₂O₃에 대한 침출 결과 GUC-LAC, ChCl-LAC, EG-MA 등 3가지 공융용매를 침출제로 사용 시 64-100%의 Nd 침출율을 획득하였다. 해당 3개의 용매를 사용하여 Fe, Fe₂O₃에 대한 침출을 수행한 결과, Fe는 모든 용매에서 94% 이상의 높은 침출율을 나타낸 반면, Fe₂O₃는 용매에 상관없이 침출율이 7% 이하로 낮게 나타났다. 기초 연구 결과를 토대로 NdFeB 자석에 대해 산화배소 유무에 따른 침출 실험을 수행한 결과 산화배소 후 NdFeO₃ 복합 산화물 형성으로 인해 Nd, Fe의 침출율이 각각 27%, 4.7%로 전처리하지 않은 자석의 침출에 비해 현저히 낮은 수준을 나타내었다. 따라서 NdFeB 자석에서 Nd를 선택적으로 회수하기 위해서는 적절한 전처리 방법의 적용을 통해 Nd₂O₃ 및 Fe₂O₃와 같이 각 산화물로의 상분리가 우선 진행되어야 함을 확인하였다.

키워드

희토류

NdFeB 자석

공융용매

침출

재활용

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Information

Publisher :The Korean Society of Mineral and Energy Resources Engineers
Publisher(Ko) :한국자원공학회
Journal Title :Journal of the Korean Society of Mineral and Energy Resources Engineers
Journal Title(Ko) :한국자원공학회지
Volume : 60
No :5
Pages :284-291
Received Date : 2023-09-11
Revised Date : 2023-10-17
Accepted Date : 2023-10-26
DOI :https://doi.org/10.32390/ksmer.2023.60.5.284

Journal of the Korean Society of Mineral and Energy Resources Engineers ISSN:2288-0291(Print) 2288-2790(Online) 한국자원공학회지

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