Features - March 2016

NETL Director Highlights Progress of Research for Separating Rare Earth Elements from Coal and Coal By-Products at National Conference

ree.jpg

During a presentation at the American Coal Ash Association (ACAA) Winter Meeting in Tampa, FL, NETL Director Dr. Grace Bochenek outlined an aggressive research initiative focused on discovering ways to separate and recover rare earth elements (REEs) from coal and coal by-products for use in an expanding array of consumer products.

REEs are chemical elements found in the Earth’s crust that have unique chemical properties that make them essential components in many technologies like hybrid vehicles, wind turbines, fluorescent lights, computer hard drives and mobile phones in addition to health care and national defense applications. Because the demand for REEs has grown significantly, the search for economically feasible and environmentally friendly approaches for REE recovery has intensified to include examination of coal as a possible source.

The ACAA, established in 1968, is a nonprofit organization devoted to recycling the materials created when coal is burned to generate electricity. Members comprise the world’s foremost experts on coal ash (fly ash and bottom ash) and boiler slag, flue gas desulfurization gypsum and other flue gas materials captured by emissions controls. The NETL director was invited to describe REE research efforts during the ACAA event.

Bochenek noted that the U.S. was once a global leader in REE production and the NETL efforts are geared toward regaining that position. She said China began production of REEs in the 1980s and by 1988 became the world’s leading producer. In 2011, global production of REEs was about 132,000 metric tons and 95 percent of that was produced by China.

“The nation’s coal resources are more than just a means of domestic energy,” she told ACAA members. “Coal and its by-products offer opportunities for our nation to become a world leader in REE production and increase the economic viability of the coal market. Successfully separated, potential REEs from coal and coal by-products exceed U.S.”

Last month, a team of researchers from NETL and Penn State’s College of Earth and Mineral Sciences published a report showing that REEs can be more efficiently removed from some U.S. coal by-product materials through an ion-exchange process that could potentially expand the U.S. domestic resource base.

Bochenek said NETL has also selected 10 projects for funding to research ways to economically separate, extract and concentrate mixed REEs from coal and coal by-products including solids and liquids from coal-related operations. The projects will include sampling and characterization of coal-related materials like coal, coal mine roof and floor materials, and coal ash to identify suitable materials for recovery of REEs. Work will also include feasibility studies and system designs for new REE recovery technologies.

The 10 projects will be conducted by research teams in academia and the private sector from the University of Wyoming, Duke University, West Virginia University, the University of North Dakota, the University of Kentucky, Neumann Systems Group Inc., Battelle Memorial Institute, Physical Sciences Inc., Southern Research Institute, and Tusaar Inc.

She said the NETL efforts have three key objectives: develop production technology that can economically recover REEs from coal and coal by-products; reduce the environmental impact of produced coal wastes and REE production from coal and coal by-products; and deliver technologies that can be developed, manufactured and deployed within the United States.

“The REE work is tied closely to the enduring core competencies of NETL,” she explained. “As the only national laboratory devoted to fossil fuel research, we use computational engineering, materials engineering, environmental systems, energy conversion, and system engineering and analysis in our work. Our REE program also draws heavily on geological and materials and geologic environmental competencies.”

She said, for example, NETL is undertaking field sampling and resource characterization to determine REE concentrations and forms and uses its own coal-based materials inventory to screen samples from coal field sites, surface outcrops, and core.

“That work is beginning to show that these materials contain REEs at concentrations ranging from 300 parts per million to 700 and 1,000 parts per million—excellent starting material concentrations for separation and recovery of mixed REEs,” she said. “Further work is needed to fully understand how to economically separate and extract REEs from these materials.”

She predicted success for the aggressive approach.

“We have an abundance of coal, processed ash, and by-product materials and many talented scientists and engineers,” she told the ACAA audience. “There is no doubt that we can meet the challenges and secure a viable market in this area. Focusing on the science and the technology, engaging the right partners, leveraging our capabilities, we can and will be successful.”