ORNL and INL develop low-cost rare earth extraction technique
June 6, 2022
At the Department of Energy’s (DOE) Critical Materials Institute (CMI), researchers from Oak Ridge National Laboratory (ORNL), Oak Ridge, Tennessee, USA, and Idaho National Laboratory (INL) have been working together to develop cost-effective technologies for the separation of in-demand, rare-earth elements (REEs). The research, supported by the DOE’s Advanced Manufacturing Office (AMO), recently moved closer to commercialisation through a licensing agreement on the production of CMI’s REE extractants by organic chemical manufacturer Marshallton Research Lab, Tobaccoville, North Carolina.
ORNL researchers developed a new extractant for REE separations by making structural changes to diglycolamide (DGA) ligands, organic molecules composed of carbon, hydrogen, oxygen, and nitrogen atoms, through the addition of substituents known as alkyls — fatty organic groups exclusively containing hydrogen and carbon atoms. Recognising that chemically modifying the structure of DGAs in this manner could improve their properties and their efficiency in extracting REEs, ORNL and INL began testing using this extractant to separate REEs.
Through testing, researchers explored ways to reduce complexity & waste, decrease costs, and simplify process sequences to limit the steps needed to achieve separation. ORNL was said to have greatly improved the ligands’ selectivity (the degree that which a solvent prefers one metal over another); the new ligands had a selectivity of 2.5–3.1.
The process’ successful demonstration and cost-competitiveness relative to existing REE separation techniques are what reportedly attracted the attention of CMI partner Marshallton Research Laboratories, Inc. Marshallton provided feedback to the research team, helping them engineer the new extractant.
The resulting REE separation process was said to significantly outperform current market equivalents. Marshallton became interested in producing the extractants and refined the process to further reduce costs, and are working now to demonstrate and scale the process. Low-cost domestic separate REE separations would make the magnet supply chain that feeds domestic production of electric vehicle motors and wind turbines more secure and resilient.