Membrane Methods of Isolation and Separation of Rare Earth Elements (A Review)

Constant growth of industry demand for rare earth elements (REE) makes it urgent to develop more efficient approaches to their production not only from mineral ores, but also from secondary sources. Thus, promising alternative sources of REE are their aqueous solutions, such as, for example, wastewater from hydrometallurgy, leaching solutions of metallurgical slags, acidic effluents of mine drainage, acidic solutions formed during recovery of valuable elements from microelectronic boards and magnets. Membrane methods of separation of liquid media allow both concentration of the sum of REEs and, most importantly, isolation of individual REEs. This review focuses on a variety of membrane methods applicable to REE recovery. It includes a brief description of the principle of each type of membrane separation and summarizes information on the use of each specific method for solving REE extraction problems. In addition, the review considers some methods of modeling of REE membrane separation, which is important due to the presence of dozens of parameters on which the final efficiency of the developed membranes depends.