With the completion of a recent field test at Pittsburgh Botanic Garden, NETL researchers demonstrated that the Lab’s basic immobilized amine sorbent (BIAS) process could successfully extract rare earth elements (REEs) from acid mine drainage, potentially providing a reliable domestic supply of critical materials needed to produce wind turbines, electric and hybrid electric vehicles, computer components, medical devices, smart phones and other valuable products. Located near Settlers Cabin Park about 10 miles west of downtown Pittsburgh, the Garden was developed on land that was once actively mined for coal and is the site of ongoing efforts to treat acidic water that drains from abandoned mining operations. NETL’s work to remove REEs from mine drainage is rooted in the development of sorbents to capture carbon dioxide (CO2) from coal-burning power plants.

Mary Anne Alvin, an NETL Technology Manager who has earned multiple awards and holds numerous scientific patents, will serve as co-editor of a new book on rare earth elements (REEs) that’s expected to provide the first comprehensive review of the technologies used to extract and process REEs for the manufacturing of high-tech products. “Rare Earth Industry Status and Prospects” is scheduled for publication release by Springer Publishing Company in May or June 2021. It will encompass the international scientific community’s expertise across the entire REE value chain — from field deposits through conventional and the latest state-of-the-art extraction, separation and processing methodologies, alloying, critical market sectors, REE application needs, and much more.  “The development of a reliable and abundant domestic supply of REEs is a priority for our nation. Being able to participate in the editing of a comprehensive, overarching book on rare earths is not only timely, it’s something that hasn’t been done to date, which positions this work as a potentially groundbreaking project,” Alvin said.

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.

An NETL collaboration with the University of Wyoming to develop technologies and methods for extracting rare earth elements (REEs) from coal ash is taking a major step forward with a recently awarded grant from the U.S. Department of Energy’s Technology Commercialization Fund. The project will work toward scaling up a patent-pending extraction technology developed by NETL researchers Christina Lopano, Ph.D., and Mengling Stuckman, Ph.D., and will ultimately result in a pilot-scale production facility. By demonstrating the economically viable production of rare earth elements from coal-related feedstocks, the project has potential to launch a new industry in extracting critical REE materials from the ash of Wyoming’s Powder River Basin coals. 

The U.S. Department of Energy (DOE) and NETL intends to make approximately $122 million available, through a competitive process, to establish coal products innovation centers. The innovation centers will focus on manufacturing value-added, carbon-based products from coal, as well developing new methods to extract and process rare earth elements and critical minerals from coal.  “It’s vitally important that America develop a viable domestic supply of rare earth elements, critical minerals, and other valuable products from our vast coal resources,” said Secretary of Energy Dan Brouillette. “This effort moves us closer to that goal. The Trump Administration has been aggressively investing in research and development for novel uses of coal that have the potential to create new markets for coal and coal byproducts. Sustaining domestic coal production creates new economic opportunity for coal state economies and benefits the Nation.”

An NETL-supported collaboration demonstrated favorable results that showed potential toward developing an environmentally benign and economically sustainable process for generating rare earth element (REE) products from domestic coal ash sources, marking a step forward in enabling a domestic supply of these critical materials. As part of an NETL-funded cooperative agreement, Battelle Memorial Institute (BMI) and Rare Earth Salts (RES) worked together to advance the development and validation of BMI’s acid digestion process, along with RES’s novel electrowinning separation and purification process. Acid digestion is a method of making metals easier to separate by first dissolving a coal ash sample into solution by adding acids and heating it until the metals break away from the other undesired materials.  Electrowinning is a process in which metal ions present in a solution are separated using a direct current.

The U.S. Department of Energy (DOE) prioritized the creation of a domestic supply of rare earth elements (REEs), and one of NETL’s supported projects that may provide these vital resources using the nation’s abundant coal supplies has demonstrated favorable results. As part of an NETL-funded cooperative agreement, researchers from the University of Utah and Virginia Tech evaluated a new, low-cost technology to extract and recover an enriched, mixed REE oxide (REO) product from coal-based resources. The project team successfully obtained six different coal waste samples with REE concentrations that exceeded the project’s requirement.

The U.S. Department of Energy’s (DOE) Office of Fossil Energy (FE) and NETL have issued a request for proposal (RFP) as an unrestricted, full, and open competition for the conceptual design of a system to produce 1–3 tonnes per day of mixed rare earth oxides or rare earth salts from domestic coal and coal by-product feedstocks. The proposal also includes an option to conduct a feasibility study sufficient to support an AACE Class 4 cost estimate to assess the technical and economic feasibility of the approach identified in the conceptual design. The contract award(s) resulting from this RFP will be firm-fixed-price.

As securing a domestic source of rare earth elements (REEs) remains a priority for the U.S. Department of Energy, a potential opportunity to obtain these elements is within reach thanks to our nation’s abundant coal resources. With support from the National Energy Technology Laboratory (NETL), the Research Triangle Institute (RTI) is exploring methods by which REEs can be extracted, separated, and recovered from coal-based resources. As part of an NETL-funded cooperative agreement, Zachary Hendren, Ph.D., and his RTI team, which include Cerahelix and Veolia Water Technologies, are testing the efficacy of various approaches to REE recovery and enrichment (with a targeted concentrated goal of 2wt% mixed REE) from acid mine drainage (AMD) samples using a combination of novel technologies. This means that of one of the nation’s most abundant resources, coal, could provide a potential source of vital REEs without the investment required to open a new mine specifically dedicated to their extraction. Already existing coal mines could provide domestic supplies if the extraction methods are refined and desired purities reached.

NETL-supported research to secure a domestic supply of rare earth elements (REEs) shows economic potential regarding efficiency and cost savings and progresses along the pathway to commercial viability. The Lab has funded and supported multiple projects across the nation to extract REEs from coal and coal-related byproducts. A notable example is coal acid mine drainage (AMD) and sludge originating from abandoned or still operating mines. However, NETL and its partners are making progress refining a method to clean up AMD in order to extract the vital REEs needed for the U.S. economy to stay competitive on the global market while providing environmental remediation. This sludge is enriched in REEs and contains an average total REE content several times higher than raw, untreated AMD. However, separating the valuable REEs can be very expensive.