Coal ash, a byproduct of coal burned for fuel, has accumulated across the United States over decades. Recent research led by The University of Texas at Austin reveals that this coal ash contains significant quantities of rare earth elements, potentially enhancing the national supply without new mining efforts.
“This really exemplifies the ‘trash to treasure’ mantra,” said Bridget Scanlon, co-lead author and research professor at UT’s Bureau of Economic Geology at the Jackson School of Geosciences. “We’re basically trying to close the cycle and use waste and recover resources in the waste, while at the same time reducing environmental impacts.”
Rare earth elements are crucial for modern technology and are used in solar panels, batteries, magnets, and other energy technologies. However, the U.S. largely depends on imports for these elements, with about 75% coming from China.
The study estimates that up to 11 million tons of rare earth elements could be extracted from accessible coal ash in the U.S., nearly eight times more than current domestic reserves. This makes it a valuable resource as outlined by co-author Davin Bagdonas from the University of Wyoming: “There’s huge volumes of this stuff all over the country.”
Approximately 70% of coal ash produced between 1985 and 2021 is potentially recoverable. Its availability in landfills and storage areas makes it an attractive resource despite its lower concentration compared to geological deposits.
Coal ash’s origin influences its rare earth element content. Appalachian Basin coal ash contains high amounts but only allows for 30% extraction; Powder River Basin coal has less but offers around 70% extractability.
Chris Young from Element USA emphasized transforming this approach into an economic strategy: “The idea of getting rare earth elements out of tailings just makes a lot of sense… The challenge is to convert that common-sense approach to an economic approach.”
Element USA plans to move analytical lab equipment to Austin to work with The University of Texas on mineral processing projects.
The study was published in the International Journal of Coal Science & Technology and funded by various organizations including the U.S. Department of Energy Office of Fossil Energy and Carbon Management.
