Coal ash, the toxic byproduct of burning coal, could become a key resource for rare earth elements critical to clean energy technologies like electric vehicles, wind turbines, and solar panels. A study led by the University of Texas at Austin estimates that coal ash from U.S. power plants contains up to 11 million tons of rare earth elements—worth around $8.4 billion—nearly eight times the country’s current domestic reserves.
Rare earth metals, such as neodymium, scandium, and yttrium, play a vital role in green technology but are challenging to extract. Despite being abundant in nature, their demand far exceeds supply. The U.S. remains heavily reliant on imports, with over 95% sourced from China, posing economic and security risks.
A New Source from Legacy Waste
Researchers believe coal ash could serve as a readily available domestic source without requiring new mining. “This exemplifies the ‘trash to treasure’ concept,” said study co-author Bridget Scanlon. The U.S. produces approximately 70 million tons of coal ash annually, and over 2 billion tons are stored nationwide. Appalachian Basin ash holds the highest concentrations of rare earth elements, while ash from the Powder River Basin offers higher extraction efficiency, recovering over 70% of the metals.
Challenges and Opportunities
Extracting rare earths from coal ash poses financial and environmental challenges. Strong acids and bases are required, raising costs and risks of chemical use. Additionally, rare earth elements form a small fraction of coal ash, which still contains hazardous contaminants like mercury, arsenic, and lead. Despite these issues, the economic value of the metals could help fund improved waste management practices.
The Biden administration has invested $17.5 million into projects for extracting rare earth elements from coal and its byproducts. Energy Secretary Jennifer Granholm stated the initiative would enhance national security, bolster U.S. manufacturing, and support mining communities.
Avoiding New Coal Dependency
Some worry that turning coal waste into a valuable resource might encourage coal use, but researchers dismiss this concern. “We are focusing on legacy waste,” Scanlon said, emphasizing that no future reliance on coal ash would incentivize coal power. Instead, the goal is to explore ways to extract rare earth elements and other valuable products without further burning coal.
This breakthrough offers a pathway to repurpose toxic waste for sustainable technologies, contributing to a cleaner energy future while reducing environmental risks and reliance on foreign imports.
