Available Technology

Green Extraction of Rare Earth Elements from Coal Waste

Current methods of mining and separating rare earth elements are not only expensive and labor intensive, they also take a devastating toll on the environment. As demand continues to increase, a secure, reliable, and sustainable domestic supply of rare earth elements from alternate sources is essential for the energy and electronics industries.

Sandia researchers have developed a new approach for converting coal ash, a by-product of coal combustion, into a viable domestic source of rare earth elements using just three readily available ingredients: water, supercritical carbon dioxide (SCO2), and food grade citric acid. By combining thermodynamic and DFT modeling and experimental tests, researchers were able to successfully remove target metals from coal and coal ash using these environmentally benign ingredients. The method has been shown to achieve a 42% extraction efficiency and can preferentially extract some of the most critical REEs.

Internal Laboratory Ref #: 
SD 15352
Patent Issue Date: 
October 20, 2021
Lab Representatives
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