The US Department of Energy’s (DOE) National Energy Technology Laboratory (NETL) has found high rare earth element (REE) concentrations in coal samples taken from the Illinois, Northern Appalachian, Central Appalachian, Rocky Mountain Coal Basins, and the Pennsylvania Anthracite region. These highly concentrated samples are greater than 300 parts per million (ppm).
Concentrations of rare earths at 300 ppm are integral to the commercial viability of extracting REEs from coal and coal by-products, making NETL’s finding significant in the effort to develop economical domestic supplies of these elements.
The current difficulties and high expenses associated with REE extraction has left the U.S. dependent on foreign REE imports. Supporting innovative research and development to establish efficient, cost-effective REE extraction methods is critical to our country’s energy and national security.—US Secretary of Energy Rick Perry
The discovery was made in partnership with West Virginia University (WVU), the University of Kentucky (UK), Tetra Tech, and the XLight Corporation.
WVU explored acid mine drainage from bituminous coal mines in the Northern and Central Appalachian Coal Basins, while Tetra Tech looked at bituminous, sub-bituminous, and anthracite coal from the same basins. Meanwhile, UK analyzed western Kentucky bituminous coal in the Illinois Coal Basin, and XLight Corporation investigated coal-related materials in the Eastern Pennsylvania Anthracite Region.
These findings could encourage technology developers to recover REEs from these basins by helping them find high quality feedstocks needed for REE recovery processes. Higher REE concentrations in the feedstock will improve the prospect of producing higher-purity REE materials. A separate research initiative is focusing on DOE cost-shared research projects to design, develop, and test technology to actually recover REEs from coal-related materials in a variety of American coal basins.
These recovery projects began in October 2017 and will use materials from the high-REE containing coal basins as feedstocks. They include WVU using acid mine drainage from bituminous mines in the Northern and Central Appalachian Coal basins as a feedstock, with final design and construction of bench-scale test facilities beginning in January 2018. A second bench-scale facility is being designed for construction by the University of North Dakota to recover REEs from lignitic material.
In addition, UK also began pilot-scale design and construction in October 2017 for systems using West Kentucky bituminous coal preparation plant refuse from the Illinois Coal basin. A second pilot-scale facility is being designed and constructed by Physical Sciences Inc.
Two additional pilot-scale facilities began in September 2017 as part of the Phase 1 project designs of small, pilot-scale, salable REE recovery systems. These include Inventure Renewables using material from the Eastern Pennsylvania Anthracite Region and Marshall Miller & Associates using Northern Appalachian Upper Freeport bituminous coal preparation plant middlings refuse.
Identifying promising sources of domestic coal and coal by-products containing high REE concentrations is a key milestone on the pathway toward economic recovery of REEs from US coal and coal by-products.