21a: Low Temperature Reduction of Rare Earth Metals using Ionic Liquids

This proposal describes development of a low temperature deposition process for the direct production of rare earth metals from rare earth oxides found in coal byproducts. This process provides a low energy alternative to the state-of-the-art for recovery of a valuable resources found in waste products (i.e. coal ash). Rare earth metals are commercially important and used in a variety of end products including wind turbines, electric cars, high performance magnets, satellites, defense aircraft, and cell phones. The overall objective of this program is the development of a low-temperature reduction method for production of high purity rare earth metals from coal byproduct feedstocks. The proposed approach is based on use of novel room temperature ionic liquid electrolytes and non-steady state electric fields to facilitate low temperature electrodeposition applicable to a variety of rare earth elements. This approach offers the benefits of lower energy requirements, lower corrosivity electrolyte which enables wider range of cell/system and substrate materials and safer operation over state-of-the-art direct current electrodeposition conducted with high temperature molten salt electrolytes. The proposed Phase I program will explore the conditions needed for low temperature deposition of rare earth metals from rare earth oxides present in fly ash. Specifically, the Phase I program will be used to investigate the electrolyte formulation needed for electrodeposition reactions, whether a solubilization agent is needed to dissolve metal species in the ionic liquid matrix, investigation of the electric field conditions needed to promote high purity deposition of rare earth metals, and preferred substrate materials. The experiments conducted in the Phase I program will help design a pilot scale system that will be designed, built and validated in the Phase II program.Rare earth elements are used for a range of industrial products including those in catalysts, alloy and magnet sectors. With no current domestic mining operations and complete reliance on imported rare earth elements, development of a process to recover rare earth elements from coal ash is anticipated to be commercially important.