In an NETL-supported collaboration with Wayne State University (WSU), researchers used a newly developed sorbent and a process previously developed for nuclear applications to produce an economically viable concentration of rare earth elements (REEs) from domestic coal fly ash, signaling an important step toward commercialization.
The new sorbent media developed by WSU researchers, in collaboration with the University of California-Los Angeles (UCLA) and Los Alamos National Laboratory (LANL), successfully concentrated the REEs in a coal fly ash sample taken from a coal-fired power plant near Detroit, resulting in a rare earth oxide (REO) powder of more than 13 percent weight, which demonstrates potential for economic viability.

Using custom-built reactors at LANL, researchers used hydrothermal leaching to extract the REE content from the fly ash. A new sorbent developed at WSU was used in a solid-liquid recovery process, which eliminated the use of potentially hazardous organic solvents. The process combined multiple techniques previously developed to process spent nuclear fuel and other nuclear materials.

“For several years, we’ve explored many ways to obtain REEs from the coal-based resources ranging from acid mine drainage to the fly ash from power plants,” NETL Project Manager Maria Reidpath said. “With this project, we’ve demonstrated that technologies developed for different purposes can be used creatively to help the nation develop its own REE feedstock.”

This development came as part of an NETL-funded cooperative agreement intended to develop a domestic supply chain for REEs, which are vital to the manufacturing of personal electronics, energy infrastructure and defense technologies, among many other high-tech applications.

The project successfully identified a commercially viable fly ash supply. With Wayne State’s hydrothermal process, more than 76% of the REEs in the coal fly ash can be extracted which represents a 20 percent increase over conventional acid-based methods.

The newly developed sorbent media that was used to concentrate REEs also demonstrated a selectivity for mid and heavy REEs and the potential for use in separating individual rare earth elements. With ease and efficient recovery of these elements, consideration for inclusion and use on a larger industrial-scale separations facility may be an opportunity in the future.

An invention disclosure for the sorbent media has been filed with WSU and a patent application will be submitted soon.  

NETL is a U.S. Department of Energy national laboratory that produces technological solutions for America’s energy challenges. From developing creative innovations and efficient energy systems that make coal more competitive, to advancing technologies that enhance oil and natural gas extraction and transmission processes, NETL research is providing breakthroughs and discoveries that support domestic energy initiatives, stimulate a growing economy, and improve the health, safety, and security of all Americans. Highly skilled men and women at NETL’s sites in Albany, Oregon; Anchorage, Alaska; Houston, Texas; Morgantown, West Virginia; and Pittsburgh, Pennsylvania conduct a broad range of research activities that support DOE’s mission to advance the national, economic, and energy security of the United States.