Rare Earth Minerals In Coal

Rare earth elements (REEs) are a group of 17 chemically similar elements that play a crucial role in various technologies, including electronics, renewable energy, and defense systems. While REEs are typically associated with minerals like bastnäsite and monazite, there’s an interesting connection between coal and rare earth minerals:

1. Coal Ash and Fly Ash:

   • When coal is burned, REEs are retained and enriched in the resulting fly ash, which is a fine-grained solid derived from noncombustible constituents of coal.
   • Fly ash has long been considered a potential resource for REEs due to its REE content¹.
   • Researchers have explored ways to extract REEs from fly ash, turning this coal byproduct into a potential source of critical materials².

2. Unconventional Feedstocks:

   • The U.S. Department of Energy (DOE) has conducted projects demonstrating the technical feasibility of producing high-purity REEs from unconventional feedstocks, including coal refuse, coal ash, and lignite coals.
   • These efforts aim to resolve challenges related to the separation, extraction, and recovery of REEs and other critical materials from coal and its byproducts².

3. REE Concentration in Coal and Sedimentary Rocks:

   • REEs are also found in coal and some sedimentary rocks.
   • Minerals such as monazite, allanite, zircon, and xenotime contain trace amounts of REEs in coal and sedimentary formations³.