Technology of rare earth separation

A brief survey is presented of the development of separation processes for lanthanides. Oxidation processes are limited to cerium, reduction processes are industrially used for Sm, Yb and Eu. The separation of the whole range of lanthanides was made possible by ion exchange chromotography which was later replaced by extraction. TBP and later DEHPA were used for the industrial application. The separation diagrams are presented of the Finnich firm Kemira OY, the Norwegien firm Megon, the French firm Rhone-Poulenc, the American Molycorp and the Chinese enterprise in Yao-Lung. (E.S.)