Research Progress in Preparation and Purification of Rare Earth Metals

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.

Synthesis of a series of validoxylamine A esters and their biological activities

“…VAA was obtained from Zhejiang Tonglu Huifeng Biosciences Co., Ltd (China). VAA hydrolyzed from VAA with sulfuric acid 8 and purified by resin 23 . Unless otherwise stated, all chemicals were purchased from Sinopharm Chemical Reagent Co., Ltd (China).…”

Solubility of Nd2O3 in LiF and LiF–NdF3 molten salts

“…The main process used to produce rare earth metals and their alloys is electrolysis of molten salts. 1,2 At present, molten salt electrolysis is used to create rare earth metals and their alloys, especially La, Ce, Pr, Nd, Dy-Fe, Gd-Fe, etc., with Pr, Nd and their alloys being the most in demand. [3][4][5] Chlorine and fluorine salt systems are the two main salt systems used in molten salt electrolysis.…”

The effect of impurity kinds and content on phase constituent and the microstructure of LaSi alloy

“…Because the electronic structures of La and Si are complex and their chemical properties are very active, the factors affected by impurities are serious. The purity of rare-Earth metal has a serious impact on electrical properties of contacts and electroluminescence properties [15][16][17][18][19]. In fact, some impurities in LaSi have a serious impact, while some impurities will not affect the performance of downstream products of LaSi.…”