Coal combustion products, including coal ash, represent an extremely rich source of rare earth metals. The United States generates approximately 115 million metric tons (mt) of coal combustion products (CCPs) annually, including 45 million mt of fly ash. CCPs therefore may represent a significant domestic supply of REEs. Further, as these materials are already mined and stored in coal ash ponds, the environmental impact is exceedingly low compared to the conventional mining of rare earth metals.
Existing technologies to extract and recover rare earth elements from CCPs are costly, inefficient, and cannot be extended to large-scale operations. Periodic Products Chelok polymers have been shown to efficiently extract and recover a range of valuable REEs from the calcium and silica rich CCP matrix. In studies using several coal ash samples from North Carolina and West Virginia, the Company’s polymers have been shown to bind nearly 100% of the REEs from the CCP extraction solution.