The principal objective of this project is to develop a novel process using low-temperature plasma treatment integrated with hydrometallurgical processes to recover rare earth elements (REEs), especially highly valued REEs (e.g., scandium and critical REEs), from coal and coal byproducts. The project will initially evaluate the mineralogy, leachability, and effect of plasma pretreatment for the various segments of selected feedstocks containing greater than 300 ppm of total REEs on a dry, whole mass basis. A laboratory low-temperature oxygen plasma unit with the ability to control test conditions will be used to optimize the operating parameters of the plasma treatment process (e.g., power, temperature, treatment time, etc.) with respect to feedstock characteristics, such as the exposed surface area, pore size, microstructure, degree of oxidation, etc. After optimizing the process, plasma treatment will be integrated with leaching, solvent extraction, and precipitation processes to produce REE concentrates at improved recovery levels and grades higher than 10 percent total REEs on a dry, whole mass basis. A techno-economic feasibility analysis of implementing plasma treatment into an overall REE recovery system will be conducted.