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

All Issue

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

PDF XML

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

References

Binnemans, K. and Jones, P.T. 2023. Ionic liquids and deep-eutectic solvents in extractive metallurgy: Mismatch between academic research and industrial applicability, Journal of Sustainable Metallurgy, 9, p.423-438. 10.1007/s40831-023-00681-6

BloombergNEF, 2022a. New Energy Outlook 2022, London, England.

BloombergNEF, 2022b.8.30. https://about.bnef.com/blog/the-road-to-electric-car-supremacy-in-five-charts/

Chen, W., Jiang, J., Lan, X., Zhao, X., Mou, H., and Mu, T., 2019. A strategy for the dissolution and separation of rare earth oxides by novel Brønsted acidic deep eutectic solvents, Green Chemistry, 21, p.4748-4756. 10.1039/C9GC00944B

Entezari-Zarandi, A. and Larachi, F., 2019. Selective dissolution of rare-earth element carbonates in deep eutectic solvents, Journal of Rare Earths, 37(5), p.528-533. 10.1016/j.jre.2018.07.015

Firdaus, M., Rhamdhani, M.A., Rankin, W.J., Pownceby, M., Webster, N.A.S., D'Angelo, A.M., and McGregor, K., 2018. High temperature oxidation of rare earth permanent magnets. Part 1 - Microstructure evolution and general mechanism, Corrosion Science, 133, p.374-385. 10.1016/j.corsci.2018.01.040

Jangir, A.K., Nain, A.K., and Kuperkar, K., 2021. Insight into structural properties and molecular interactions of maline (choline chloride + malonic acid) and 1, 4- butanediol based pseudo-binary mixture: A thermophysical, spectral, and simulation portrayal, Journal of Molecular Liquids, 334, 116050p. 10.1016/j.molliq.2021.116050

Karan, R., Sreenivas, T., Kumar, M.A., and Singh, D.K., 2022. Recovery of rare earth elements from coal flyash using deep eutectic solvents as leachants and precipitating as oxalate or fluoride, Hydrometallurgy, 214, 105952p. 10.1016/j.hydromet.2022.105952

Kumari, A., Sinha, M.K., Pramanik, S., and Sahu, S.K., 2018. Recovery of rare earths from spent NdFeB magnets of wind turbine: Leaching and kinetic aspects, Waste Management, 75, p.486-498. 10.1016/j.wasman.2018.01.03329397277

Liu, C., Yan, Q., Zhang, X., Lei, L., and Xiao, C., 2020. Efficient recovery of end-of-Life NdFeB permanent magnets by selective leaching with deep eutectic solvents, Environmental Science & Technology, 54, p.10370-10379. 10.1021/acs.est.0c0327832673480

Önal, M.A.R., Aktan, E., Borra, C.R., Blanpain, B., Van Gerven, T., and Guo, M., 2017. Recycling of NdFeB magnets using nitration, calcination and water leaching for REE recovery, Hydrometallurgy, 167, p.115-123. 10.1016/j.hydromet.2016.11.006

Riaño, S., Petranikova, M., Onghena, B., Vander Hoogerstraete, T., Banerjee, D., Foreman, M.R.S., Ekberg, C., and Binnemans, K., 2017. Separation of rare earths and other valuable metals from deep-eutectic solvents: A new alternative for the recycling of used NdFeB magnets, RSC Advances, 7(51), p.32100-32113. 10.1039/C7RA06540J

Seo, H.S. and Park, B.H., 2015. Properties of Deep Eutectic Solvents (DESs) and Their Applications, Journal of Institute of Convergence Technology, 5(2), p.43-48.

Škulcová, A., Majová, V., Šima, J., and Jablonský, M., 2017. Mechanical properties of pulp delignified by deep eutectic solvents, BioResources, 12(4), p.7479-7486. 10.15376/biores.12.4.7479-7486

Smith, E.L., Abbott, A.P., and Ryder, K.S., 2014. Deep eutectic solvents (DESs) and their applications, Chemical Reviews, 114, p.11060-11082. 10.1021/cr300162p25300631

U.S. DOE, 2022. Rare Earth Permanent Magnets: Supply Chain Depp Dive Assessment, U.S. DOE Response to Executive Order 14017, "America's Supply Chains", Washington, DC, USA, 67p.

Yan, Q., Liu, C., Zhang, X., Lei, L., and Xiao, C., 2021. Selective dissolution and separation of rare earths using guanidine-based deep eutectic solvents, ACS Sustainable Chemistry & Engineering, 9(25), p.8507-8514. 10.1021/acssuschemeng.1c01616

Yang, Q., Li, Y, Li, B., Duan, P., Ren, Z., and Zhou, Z. 2024. Selective leaching and recovery of neodymium from NdFeB carbonyl residues, Separation and Purification Technology, 329, 125137p. 10.1016/j.seppur.2023.125137

Yoon, H.S., Kim, C.J., Chung, K.W., Jeon, S., Park, I., Yoo, K., and Jha, M.K., 2015. The effect of grinding and roasting conditions on the selective leaching of Nd and Dy from NdFeB magnet scraps, Metals, 5(3), p.1306-1314. 10.3390/met5031306

Yoon, H.S., Kim, C.J., Chung, K.W., Kim, J.H., Lee, E.J., and Yoo, S.J. 2017. Double salt precipitation behavior of rare earth by sodium sulfate in sulfuric liquor of waste permanent magnet scrap, Resources Recycling, 26(5), p.39-47.

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 한국자원공학회지 ISSN:2288-0291(Print) 2288-2790(Online)

All Issue