This book comprehensively details the applications of ionic liquids in rare earth green separation and utilization based on the unique interactions of ionic liquids with rare earth ions. It consists of nine chapters demonstrating the synthesis and properties of ionic liquids, coordination chemistry of ionic liquids and rare earth, ionic liquids as diluents, extractants, adsorption resins for rare earth extraction and separation, electrodeposition of rare earth metals in ionic liquids, and preparation of rare earth material with the aid of ionic liquids. It is both interesting and useful to chemists, metallurgists and graduate students working on fundamental research of ionic liquids as well as professionals in the rare earth industry. It provides considerable insights into green chemistry and sustainable processes for rare earth separation in order to meet the environmental challenge of rare earth metallurgy around the globe, especially in China. Ji Chen is a Professor of Chemistry at the Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, China.