Recovery of High Purity Rare Earth via a Novel Electrowinning Process

Technology Partner: Battelle Memorial InstituteAward Number: FE0031529
Project Duration: 11/16/2017 – 5/15/2019Total Project Value: $874,940

Key Technology Area: Separation TechnologiesProject Partners: Rare Earth Salts

The objective of this project is to advance development and integration of the novel electrowinning separation and purification process developed by Rare Earth Salts (RES) and Battelle’s acid digestion process, and validate that they can generate environmentally benign and economically sustainable rare earth element (REE) products from domestic coal ash sources at purities above 90 percent. An additional objective is to enable domestic REE sources and new outlets for coal products by demonstrating advancements in these purification technologies on coal-based feedstock. These objectives will be accomplished by testing at laboratory scale. Battelle’s acid digestion process will be used to upgrade the REE concentrate via solvent extraction, eliminating less-valuable elements such as iron, aluminum, sodium, and calcium, and carefully avoiding enrichment of contaminants such as uranium and thorium. REE

Elements (REEs) from Coal Ash

products will then be separated and purified from this upgraded solution using RES’s novel electrowinning process—a purification process that can reduce the number of stages and cost of REE purification compared to traditional solvent extraction circuits. The project team will perform a preliminary design of a commercial- scale system, using data obtained during lab testing, to generate preliminary capital and operating costs for the process. The outcome of this project will advance Battelle’s solvent extraction REE upgrading process, RES’s process, and their application to domestic coal- derived feedstocks by validating their feasibility in both technical and economical terms. A high-purity (greater than 99 percent) product of separated REE will be generated by the RES process-derived from fly ash extracted with Battelle’s acid digestion process from an operating pulverized coal combustion plant.

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Solvent extraction upgrading of coal ash pregnant leach solution.

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