K.P. McCarthy, T. Watkins, L.C. Merrill
Sandia National Labs,
United States
Keywords: electrokinetic, purification
Summary:
Rare earth element (REE) separation and purification is incredibly difficult due to the similar physical and chemical properties of the REEs. REEs are vital for new and emerging electronic technologies with demand projected to increase. Liquid-liquid extraction is currently the primary method used for REE recovery, but due to its low single pass efficiency and large production of hazardous waste, there is substantial need for new, greener, and more economic purification techniques. Large scale REE purification demands 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 an electrokinetic purification technique that exploits the increased difference in REE electrophoretic mobility when solvated with specific ligands. Ionic polymer coated silica capillary arrays with tunable electro-osmotic mobility allow for REEs to be isolated by electrophoretic mobility in an applied electric field. We demonstrate the viability of this technique to isolate and purify REEs. This electrokinetic purification shows the potential for an environmentally friendlier and low energy REE purification technique. 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.