Sustainable Recycling of Rare-Earth Elements from NdFeB Magnet Swarf: Techno-Economic and Environmental Perspectives

Abstract

Rare-earth elements (REEs) are increasingly susceptible to supply risks due to their limited geographical availability and growing demand in clean energy applications such as neodymium-iron-boron (NdFeB) magnets used in electric vehicles and wind turbines. When NdFeB magnets are produced, 6−73% of swarf is generated during the manufacturing steps. This paper presents an innovative technology that utilizes copper nitrate to dissolve REEs in NdFeB magnet swarf and subsequently recovers ∼97% of them as mixed rare-earth oxides (REOs) of purity higher than 99.5%. Techno-economic analysis (TEA) and life cycle assessment (LCA) quantified the economic and environmental impacts of adopting the proposed acid-free dissolution technology, projecting a net profit margin of 12−43% and a global warming impact reduction by up to 73% compared to the prevailing REO production routes in China. As copper nitrate is the single largest contributor to the cost and environmental footprint, recycling of copper nitrate was investigated as well as using alternative copper salts (e.g., copper acetate), revealing significant improvements in TEA and LCA results. Dysprosium was a major revenue source, highlighting the importance of targeting electric vehicle magnets that are rich in dysprosium. As the REO market is volatile, sensitivity analysis was employed to evaluate the profitability of the proposed technology under different REO prices over the last 11 years. Overall, our results confirmed the economic and environmental viability of the proposed technology for sustainable recycling of REEs from the NdFeB magnet swarf.

Scalable and Consolidated Microbial Platform for Rare Earth Element Leaching and Recovery from Waste Sources

“…Selective Bioaccumulation of REE from Nd Magnet Swarf. Even high-grade feedstocks like Nd magnet swarf are of mixed composition and therefore vary in the content of highly valuable REE and associated metals, 47 making selectivity crucial for the development of a successful recovery platform. We determined the precise metal content of the Nd magnet swarf used in our growth and recovery experiments using ICP-MS. Iron was the primary metal component of Nd magnet swarf (68.0% Fe), rendering nonselective leaching and uptake mechanisms insufficient for effective REE bioaccumulation.…”

Scalable bio-platform to recover critical metals from complex waste sources

“…Even high-grade feedstocks like Nd magnet swarf are of mixed composition, and therefore vary in the content of highly valuable REE and associated metals, [48] making selectivity crucial for the development of a successful recovery platform. We determined the precise metal content of the Nd magnet swarf used in our growth and recovery experiments using ICP-MS. Iron was the primary metal component of Nd magnet swarf (68.0% Fe), rendering non-selective leaching and uptake mechanisms insufficient for effective REE bioaccumulation.…”

Challenges and opportunities for sustainable valorization of rare earth metals from anthropogenic waste

“…Kaya et al have reported NdFeB permanent magnet recycling by an alternate route sequential griding, sieving, acid baking, calcination, water leaching to recover Fe 2 O 3 and purify REM and finally REM recovery by ultrasonic spray pyrolysis (Kaya et al 2021 ). Chowdhury et al analyzed the sustainable recycling aspect of NdFeB permanent magnet from a techno-economical-environment perspective (Chowdhury et al 2021 ). Chowdhury et al have investigated the techno-economical aspect of REM recovery by sequential acid-free Cu(NO 3 ) 2 leaching followed by REM recovery as REM oxalate and finally REM oxide valorization by calcination.…”