Chromatographic Methods in the Separation of Rare-Earth Elements

A review is presented of literature sources published in Russia and abroad, mainly over the past 10–15 years, concerning the use of chromatographic methods in the separation of rare-earth elements. Analysis of the published data shows that liquid chromatography is currently the most widely applied technique due to its versatility in separation modes, reliability, and rapid operation. Although chromatographic methods are significantly inferior to extraction in terms of throughput, they can be extensively employed in, for example, ultrafine purification processes and the production of individual rare-earth elements of exceptionally high purity. Liquid–liquid chromatography, in which both phases remain in the free liquid state and the separation processes are similar to nonstationary extraction, is noted as the most promising approach for the separation of rare-earth elements. The implementation of such extraction–chromatographic separation processes on an industrial scale is feasible using standard industrial extraction equipment, such as a cascade of extraction columns or a cascade of mixer–settler extractors.