The purity of rare earth metals is one of the most important factors to research and develop high technique materials. However, high purity rare earth metals are not easily achieved. This review summarizes the preparation and purification methods of rare earth metals. First, the preparation principle and process of molten salt electrolysis and metal thermal reduction are introduced. The main sources of metallic impurities and interstitial impurities in rare earth metals as well as the action mechanism of reducing the concentration of different impurities are analyzed and summarized. Then, the purification principle and process of vacuum distillation, arc melting, zone melting, and solid state electromigration are also discussed. Furthermore, the removal effect and function rule of metallic impurities and interstitial impurities in rare earth metals are outlined. Finally, the crucial issues in the development of high purity rare earth metals are put forward, and the development direction of high purity rare earth metals in future are pointed out on this basis.

中文翻译：

---

稀土金属的制备与纯化研究进展

稀土金属的纯度是研究和开发高科技材料的最重要因素之一。但是，不容易获得高纯度的稀土金属。这篇综述总结了稀土金属的制备和纯化方法。首先介绍了熔融盐电解和金属热还原的制备原理和工艺。分析和总结了稀土金属中金属杂质和间隙杂质的主要来源以及降低不同杂质浓度的作用机理。然后，讨论了真空蒸馏，电弧熔化，区域熔化和固态电迁移的纯化原理和过程。此外，概述了稀土金属中金属杂质和间隙杂质的去除效果及作用规律。最后，提出了高纯稀土金属发展中的关键问题，并在此基础上指出了未来高纯稀土金属的发展方向。