With the scarcity of resources and the growing consumer demand for rare earth elements (RE), it is imperative to develop clean and sustainable methods to recover these valuable elements. This research proposes a novel green process for the selective recovery of RE from spent NdFeB permanent magnet using hydrophobic deep eutectic solvent (HDES). A total of 13 HDES systems composed of trioctylphosphine oxide (TOPO) as hydrogen bond acceptor (HBA) and alcohols as hydrogen bond donor (HBD) were prepared and characterized. Through a simple screening process, it was determined that ternary HDES (DA:MA:TOPO = 5:5:4) exhibited the best extraction and separation performance for REs and Fe. The extraction conditions such as aqueous phase acidity, organic/aqueous phase ratio, the concentration of Fe³⁺ and equilibration time were further studied and optimized. Under the most suitable conditions, HDES (DA:MA:TOPO = 5:5:4) was used for batch countercurrent extraction, where the concentration of REs in the raffinate was lowered from 4390 mg/L to 34 mg/L, and the recovery reached 99%. The HDES could be stripped by 0.2 mol/L Na₂C₂O₄, which could further separate a small amount of loaded Fe (133 mg/L) and RE, so that the purity of the final product reached >99%. The stripped HDES could be recovered after washing with deionized water. Even after five cycles, HDES still maintained good stability. This innovative process does not require the use of salting-out agents or toxic volatile solvents, providing new possibilities for efficient and clean separation.

随着资源的稀缺和消费者对稀土元素（RE）的需求不断增长，开发清洁且可持续的方法来回收这些有价值的元素势在必行。这项研究提出了一种利用疏水性低共熔溶剂 (HDES)从废 NdFeB 永磁体中选择性回收稀土的新型绿色工艺。制备并表征了总共 13 个由三辛基氧化膦 (TOPO) 作为氢键受体 (HBA) 和醇作为氢键供体 (HBD) 组成的 HDES 体系。通过简单的筛选过程，确定三元 HDES（DA:MA:TOPO = 5:5:4）对 REs 和 Fe 表现出最佳的萃取和分离性能。^{萃取条件如水相酸度、有机/水相比、Fe 3+}浓度和平衡时间进行了进一步的研究和优化。在最适宜的条件下，采用HDES（DA:MA:TOPO=5:5:4）进行间歇逆流萃取，萃余液中REs浓度从4390mg/L降至34mg/L，回收率达到99%。HDES可以用0.2 mol/L Na ₂ C ₂ O ₄反萃取，进一步分离出少量负载的Fe（133 mg/L）和RE，使最终产品的纯度达到>99%。用去离子水洗涤后可以回收剥离的HDES。即使经过五个循环后，HDES仍然保持良好的稳定性。这一创新工艺不需要使用盐析剂或有毒挥发性溶剂，为高效清洁分离提供了新的可能性。