Review of rare earth oxide (nano and micro sized crystalline) materials: Preparation from rare earth chlorides, characterisation and applications

Due to the exceptional performance and irreplaceable nature of materials containing rare earth metals, their application across various fields of modern society is increasingly widespread. China possesses substantial reserves and abundant resources of rare earth elements, which confer a unique edge in their research and application. However, challenges such as an oversupply of low-end products and a shortage of high-end products hinder the advancement of processing science and technology. For the first time, this paper provides a comprehensive summary of the current processes used worldwide, and research for the preparation of rare earth oxides (REOs) from rare earth chlorides (RECs), and analyses the advantages and disadvantages of these processes. To address the issues of the need for additional conversion agents and wastewater discharge in the preparation of REOs from RECs, this review based on previous work proposes the preparation of REOs through ion membrane electro-conversion based on the chlor-alkali industry and discusses their development and application. Finally, the paper forecasts the future development trends in the preparation processes of REOs.