L. Ward, C. Tolbert, C. Orme, D. Prodius, I. Nlebedim, A.D. Wilson
Idaho National Laboratory,
United States
Keywords: rare earth elements, crystallization, lanthanides, magnet materials, primary recovery, recycling, waste treatment
Summary:
Lanthanides are important to many technologies including magnets used in high efficiency traction motors. While common in the environment and industrial waste streams, lanthanides are often present at very low concentrations. This presentation will discuss the use of enhanced pressures dimethyl ether fractional crystallization (DME-FC) with temperature control to recover lanthanides from an aqueous magnet leachate. The application of pressures (up to 4,000 psi) reduced lanthanides to ppb concentrations (single ppb in the presence of oxalate) achieving a greater than 5 log reduction/recovery of the lanthanides from the magnet leachate. It was found that enhanced pressure DME-FC favored the recovery of heavy rare lanthanides (Gd, Dy, and Ho) over light (Pr, Nd, and Sm). Given a very limited change in solution volumes during the increase in pressure and the high-efficiency of pressure exchangers (up to 98%), enhanced pressure DME-FC has the potential to be a low energy recovery or treatment technology. DME-FC piloting efforts at 2 gallons per minute will also be presented.