Economic Extraction, Recovery, and Upgrading of Rare Earth Elements from Coal-Based Resources

Technology Partner: University of UtahAward Number: FE0031526
Project Duration: 11/16/2017 – 5/15/2019Total Project Value: $499,000

Key Technology Area: Separation Technologies
Project Partners: Virginia Polytechnic Institute and State University

The objective of this project is to demonstrate and improve methods that can economically extract, recover, and upgrade the rare earth elements (REEs) contents from coal-based resources using integrated modeling, coal preparation, bio-oxidation, solution conditioning, heap leaching, solvent extraction, and precipitation technologies to cleanly and cost- effectively produce rare earth-bearing products with more than 8 percent by weight REE. The project encompasses a range of technologies currently in industrial practice to produce REE products from coal- based sources. Advanced coal processing technology will deliver clean coal for the market as well as REE- bearing coarse refuse (non-coal rock) that is the correct size for heap leaching applications. In addition, the technology provides concentrated sulfide minerals (for mid-to-high-sulfur coals) for cleaner coal and enhanced biooxidation to accelerate leaching of REEs from the coarse refuse. The removal of the sulfide minerals cleans the coal, accelerates subsequent REE extraction,

and eliminates the potential for most acid rock drainage. The processing method also utilizes biooxidation to increase ferric ion production to enhance leaching, while also consuming the sulfide mineral and its associated environmental liability. The solution-conditioning processing method removes iron and controls the pH of the leaching solution to mitigate undesirable extraction of thorium, which often occurs below pH 1.5; the heap leaching portion will be modeled and designed to maximize extraction of REEs while minimizing thorium extraction. The solvent extraction portion of the project involves optimizing extraction and stripping for REE recovery in solution that will be precipitated as a final product in the last stage of precipitation processing. This project will provide the technology and data needed to facilitate large-scale implementation that can provide a domestic REE supply that is low in thorium, create revenue and jobs for the coal industry, and mitigate future acid rock drainage issues.

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Flow sheet diagram for low-cost extraction, concentration, and recovery of REE product.

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