2022 Fiscal Year Final Research Report
Recycling of end-of-life neodymium magnet based on liquid-alloy deposition trough electrorefining of molten salt
Project/Area Number |
20K15069
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Research Category |
Grant-in-Aid for Early-Career Scientists
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Allocation Type | Multi-year Fund |
Review Section |
Basic Section 26060:Metals production and resources production-related
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Research Institution | Tohoku University |
Principal Investigator |
LU XIN 東北大学, 工学研究科, 助教 (00781452)
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Project Period (FY) |
2020-04-01 – 2023-03-31
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Keywords | レアアース / リサイクル / 溶融塩電解 / ネオジム磁石 / 資源保全 / 電気化学 |
Outline of Final Research Achievements |
The effects of various electrochemical factors were investigated to recover Nd from waste neodymium (Nd) magnets as an Nd-Fe alloy using a chloride-based molten salt electrolytic bath. In the LiCl bath at 1073K, the dissolution potential of Nd in the waste Nd magnet is -2.9V (chlorine reference potential), which is much more negative than the other main components so that Nd was preferentially dissolved and separated in the bath during electrolysis. It was clarified that the reduction reaction of Nd ions (Nd(III)) is a two-step reaction in the chloride system, but it tends to become a one-step reaction by the addition of fluoride ions. Furthermore, Nd can be recovered as Nd-Fe alloy by controlling the initial concentration of iron ions in the electrolytic bath and the supply rate.
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Free Research Field |
金属リサイクル
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Academic Significance and Societal Importance of the Research Achievements |
ネオジム(Nd)磁石は電気自動車などの各種工業製品に必要であるが、現在Ndの安定かつ持続的な供給が懸念されている。Ndの潜在的な供給危機への対策として、本研究では、低温操業・低環境負荷の塩化物浴を用い、微小電圧での廃Nd磁石の溶融塩電解回収法による新規Nd回収プロセス開発を行った。本研究により、(1)電解浴中のNdイオンの電気化学挙動を解明し、(2)溶融塩におけるレアアースイオンの電位化学挙動に及ぼすカチオンの影響の知見を得た。開発したプロセスは廃Nd磁石中のNdをNd-Fe合金として回収するため、安価で低環境負荷のNd回収が可能となり、産業にとって大きな貢献となる。
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