Sandia Labs FY22 Laboratory Directed Research & Development Annual Report

FY22 ANNUAL REPORT

EXTRACTION AND SEPARATION OF RARE-EARTH ELEMENTS FROM DOMESTIC WASTE USING CITRIC ACID.

A secure, reliable, and sustainable domestic supply of rare-earth elements (REE) is essential to national security. The goal of this LDRD project was to develop an environmentally benign method to extract and separate REEs from coal and coal byproducts, the materials known to be

Regional partner New Mexico State University and Alliance partner University of New Mexico, as well as National Energy Technology Laboratory and the University of Tennessee. This work, awarded a 2021 R&D 100 GOLD Special Recognition in Green Technology award, will also help ensure

A comparison of Sandia’s method for extracting rare-earth metals to existing methods shows how using citric acid is more efficient.

enriched in REE contents. The work features a method that uses environmentally harmless citric acid in tandem with carbon dioxide to detoxify coal tailings by extracting critically needed rare elements and more harmful components at the same time. Further, the extraction improves the environment instead of destroying it as conventional mining may. Research was performed at various stages with Sandia National/

supply chain security and improve economic competitiveness for the nation. Credited to this LDRD work, two additional projects, $187K and $1.2M, respectively, were funded by DOE Office of Fossil Energy and Carbon Management to evaluate critical mineral resources in San Juan-Raton Basin, and in unconventional shale resources, respectively. (PI: Guangping Xu)

Sandia researcher Guangping Xu adds coal ash into a citric acid mixture. This solution will be fed into a reactor— operating at about 70 times atmospheric pressure—where supercritical carbon dioxide aids citric acid in extracting rare earth metals. (Photo by Rebecca Gustaf)

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