Electrokinetic Rare Earth Element Purification

Rare earth elements (REEs) are vital components in new and innovative electrical technologies and are in high demand worldwide. Primary mineral deposit sources of REEs are limited for most countries, leading to a large dependance on secondary recycled sources including magnets, LEDs, LCDs, cathode ray tubes, and phosphorous lamps amongst other industrial waste. Hydrometallurgical techniques<b> </b>are an effective route for REE recovery yet are limited by the difficult purification of REEs due to their similar physical and chemical properties. Currently, liquid-liquid extraction is required for significant REE recovery, but due to low single pass efficiencies and large hazardous waste production of hazardous waste, there is substantial need for new, greener, and more economic purification techniques. Large scale REE purification can be improved by<b> </b>low energy consumption, low waste generation, high REE selectivity, and high insensitivity to acidic leaching conditions in an economically feasible and environmentally friendly process. We describe here an electrokinetic based REE purification method using ionic polymer coated silica capillaries. This technique drives selective REE purification through electromigration of solvated REEs against an induced electroosmotic flow in an applied electric field. We show the viability of this process to individually isolate REEs and the potential for larger scale REE purification through an array of coated capillaries. This electrokinetic purification shows the potential for an environmentally friendlier and low energy technique for REE purification.<br/> <br/>Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.