Opportunity

Recovering rare earth elements (REEs), or critical minerals from domestic sedimentary materials remains difficult using conventional hightemperature strong-acid leaching processes that dissolve large amounts of unwanted minerals and introduce safety, waste-handling and cost barriers. The U.S. Department of Energy’s National Energy Technology Laboratory (NETL) has established a low-temperature extraction method that uses tailored organic acid solutions containing both an organic acid and an ionic salt to selectively mobilize REEs from underclays, claystones, shales, coal-mining waste and waste coal. These Organic Acid Solutions (OAS) operate at nearambient temperatures and moderate pH levels, allowing selective leaching of rare earths and yttrium while substantially limiting dissolution of iron, aluminum, thorium and other problematic gangue elements. By leveraging mild chemistries inspired by natural weathering processes, the approach can reduce processing hazards, shorten extraction steps and enable the productive use of clay-rich materials that are currently discarded. This technology is available for licensing and/or further collaborative research from NETL.