(270f) High Yield and Economical Extraction of Rare Earth and Critical Elements from Coal Ash

Rare earth elements (REEs) are strategically important minerals with very limited domestic production. Coal and coal byproducts are a potential source of rare earth elements (REEs) with significant heavy rare earth element (HREE) content. Technologies enabling the environmentally benign recovery of REE, yttrium and scandium (REYSc) from coal combustion byproducts (coal fly ash) would provide the United States with a domestic supply of these strategically important materials while generating jobs and supporting economic growth. Under sponsorship from the Department of Energy, the team of Physical Sciences Inc., University of Kentucky/Center for Applied Energy Research, and Winner Water Services has developed and demonstrated a pilot scale plant to economically produce salable REYSc-rich concentrates and commercially viable co-products from coal ash feedstock using environmentally safe and high-yield physical and chemical enrichment/recovery processes. The pilot plant operates at the scale of approximately 0.4-1 tons per day (tpd) ash throughput for physical processing and about 0.5 tpd for chemical processing, producing at least 50 - 500 g of dry REYSc nitrates concentrate containing at least 10-20 wt.% REYSc (elemental basis). Various ash feedstocks have been qualified, and all contain between 400-500 ppm of REYSc. This presentation will describe our approach and key results for current work at the pilot scale in process optimization and efforts to increase the purity of the extracted rare earth elements to above >85 wt.% REYSc. The talk will also cover characterization of additional processes for the recovery and purification of critical materials as co-products from waste process streams. Target critical materials include aluminum (>50 wt.% purity) and scandium (>85 wt.% purity). The data obtained from the pilot plant optimization and the addition of aluminum and scandium co-products will be used to enhance and validate a commercial scale techno-economic analysis to enable the design of a commercial scale (hundreds of tpd) REYSc plant.

Acknowledgement: This material is based upon work supported by the U.S. Department of Energy under Award DE-FE0027167.

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