Research Progress in Preparation and Purification of Rare Earth Metals

Yao Zhang,Dianzhong Li,Yikun Luan,Hang Liu,Huimin Yu

doi:10.3390/met10101376

Yao Zhang, Dianzhong Li + Show 3 more

Open Access

https://doi.org/10.3390/met10101376

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Abstract

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.

Highlights

Rare earth element is the general name of 17 special elements, containing lanthanide element, scandium, and yttrium
RE hydrogen storage alloy shows the advantages of high electric capacity, good stability, high hydrogen absorption efficiency, and no pollution, which makes it to be widely used in the fields of battery, brake, and refrigeration [7]
Nd are produced by molten salt electrolysis for considering economic cost reduction method is more suitable for preparing heavy rare earth metals such as Gd, Tb, and Y with factors such asand fixed assetpoints

Summary

Introduction

Rare earth element (named as RE) is the general name of 17 special elements, containing lanthanide element, scandium, and yttrium They have been widely applied in functional materials, steel, and nonferrous metals because of their special optical, electrical, and magnetic properties. United States, Japan, and other countries have even listed RE products as the key strategic elements and purification of high-purity raretechnology earth metals hashigh attracted more industries. Japan, and countries even economic listed RE science The and relevant technology, high purity earth metals play a other critical role in have national products as the key strategic elements for the development of military technology and high technique construction and daily life [12,13]. With the progress of science and technology, high purity rare earth metals play a critical role in national economic construction andMetals daily life [12,13]

Progress in wide

Molten

Schematic

Effect

Metal Thermal Reduction

Zone Melting

Solid State Electromigration

Findings

Summary and Prospect