Nearly $100 Billion in Rare Earth Elements Could Be Hidden in the US

Researchers have identified that the remnants of burned fossil fuels may hold vast quantities of rare-earth elements (REEs) potentially worth billions of dollars. A study published in 2024 suggests that coal ash from power plants might contain up to US$165 billion in REEs, with approximately $97 billion being practically recoverable.

The research, led by geoscientists at the University of Texas at Austin, highlights the opportunity to create a domestic source of these critical elements, reducing dependence on imports, which currently supply most of the United States REEs. "This is a clear example of turning waste into wealth," said Bridget Scanlon of the Jackson School of Geosciences. "Our goal is to close the loop, recover resources from waste, and mitigate environmental impacts."

Rare-earth elements consist of 17 elements: the 15 lanthanides plus yttrium and scandium. They are vital for numerous technologies, including batteries, wind turbines, electric vehicles, and smartphones. The U.S. holds limited REE reserves and relies on imports, mainly from China, which supplies around 70% of the countrys needs.

The potential lies in the 52 billion tons of coal ash produced by U.S. power plants since the 1950s. Coal naturally contains trace elements absorbed over millions of years. While these elements are minimal in raw coal, burning it concentrates them in the ash. Non-combustible materials such as clay, quartz, and REEs remain, increasing the concentration of REEs by 4 to 10 times compared to unburned coal. Although still lower than commercial ores, extracting REEs from coal ash avoids additional mining, making it economically attractive.

Scanlon and geologist Robert Reedy analyzed decades of data on ash composition, extraction feasibility, and storage locations. They estimate that 11 million tons of REEs exist in coal-ash deposits from 1985 to 2021nearly eight times current U.S. reserves. The total potential value of the 15 lanthanides in all U.S. coal ash is about $56 billion, with accessible ash estimated at $14 billion. Recoverable lanthanides could be worth up to $8.4 billion. Including yttrium and scandium raises the total to $165 billion, with $97 billion recoverable.

Extraction techniques are still being developed, but the potential economic benefits are significant. "Developing REE resources from coal ash could enhance energy security and help fund remediation of unlined ash landfills," the researchers note. They emphasize the global applicability of coal-ash REE recovery wherever the waste is available.

Other approaches to sourcing REEs include mining extinct volcanoes and using plants. Some volcanic sites could be modified to produce REEs alongside iron ore. Recently, scientists discovered a fern capable of absorbing and storing REEs from metallic soils, offering a sustainable method called phytomining. "REEs are crucial for clean energy and high-tech applications, but supply faces environmental and geopolitical hurdles," noted Liuqing He of the Chinese Academy of Sciences. "Phytomining presents a green alternative that remains underexplored."

The study on coal ash was published in November 2024 in the International Journal of Coal Science & Technology, highlighting a promising avenue for domestic REE production while addressing environmental challenges.

Author: Sophia Brooks