Abstract Recovery of rare earth (RE) elements from Nd-Fe-B waste is one of the ways to solve the problem of so-called RE-crisis. An alternative approach of extracting RE elements from Nd-Fe-B waste by molten Cu extraction based on liquid-solid diffusion and reaction is reported in this paper. The extraction process, product microstructure and extraction efficiency were systematically studied. The results show that the extraction rate of RE at 1200 °C is about 20% higher than that at 1100 °C. The enhanced extraction efficiency at 1200 °C results from the fact that the liquid Fe and Fe2B are not co-soluble with Cu. Reducing the mass ratio of Cu to waste and the size of the waste scraps is also beneficial to enhancing the separation of RE and Fe elements. In addition, the extraction time should be well controlled, for example, less than 2 h at 1100 °C, in order to avoid the increased Fe content in the extracted product. Based on optimized process, the RE elements can be almost fully extracted from the waste. This work thus provides an effective method to recover the RE elements.

中文翻译：

---

液态铜提取法从Nd-Fe-B废料中有效提取稀土的研究

摘要 从 Nd-Fe-B 废料中回收稀土 (RE) 元素是解决所谓的稀土危机问题的途径之一。本文报道了一种基于液固扩散和反应的熔融铜萃取从 Nd-Fe-B 废料中提取稀土元素的替代方法。系统研究了提取工艺、产物微观结构和提取效率。结果表明，稀土在1200℃时的提取率比1100℃时提高了约20%。1200 °C 时萃取效率的提高是由于液态 Fe 和 Fe2B 不与 Cu 共溶。降低Cu与废料的质量比和废料的尺寸也有利于加强RE和Fe元素的分离。另外，提取时间要控制好，例如，在 1100°C 时少于 2 小时，以避免提取产物中的 Fe 含量增加。基于优化的工艺，RE元素几乎可以从废物中完全提取。因此，这项工作提供了一种有效的方法来恢复 RE 元素。