Clean metallurgy and technical progress of light rare earth minerals

• Published in: Canadian metallurgical quarterly 2024-04, Vol.ahead-of-print (ahead-of-print), p.1-13
• Main Authors: Shule, Qiao, Xue, Bian, Jianguo, Cui, Peng, Cen, Wenyuan, Wu
• Format: Article
• Language: English
• Subjects: Bastnaesite; cleaner production; mixed rare earth concentrate; smelting process
• ISSN: 0008-4433; 1879-1395
• DOI: 10.1080/00084433.2023.2193522

Bastnasite and mixed rare earth concentrates are the two main rare earth minerals in the world, which are located in China, the United States and Canada, and they account for more than 80% of the annual global rare earth ore production. The oxidation roasted method of bastnasite and the sulphuric acid roasted method of mixed rare earth concentrates are the main processes. Although the yield of rare earth can reach over 90%, the problems are long process, high acid and alkali consumption and radioactive waste. For this reason, a number of clean smelting processes are developed such as low temperature sulphuric acid roasting of mixed rare earth concentrates, magnesium bicarbonate smelting, combined acid-base decomposition. Firstly, this paper summarises the current processes for both minerals and the improvements in recent years, as well as the new technologies in terms of rare earth extraction rates and the effect of comprehensive resource utilisation. Finally, this paper reviews the problems that exist in the different smelting methods. It is recommended to consider the comprehensive recovery of valuable resources such as fluorine, phosphorus, calcium and thorium in the development of clean smelting processes to achieve green and sustainable development of rare earth smelting.