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An acid-mine sludge pond in central Pennsylvania. A byproduct of coal mining, such sites may be rich with critical minerals. Credit: Provided by Sarma Pisupati. All Rights Reserved.

By Patricia Craig

UNIVERSITY PARK, Pa. — A Penn State research team was recently awarded a $4.99 million grant from the U.S. Department of Energy (DOE) to develop and assess advanced separation technologies for the extraction and recovery of rare earth elements and other critical materials from coal, coal wastes and coal by-products.

The materials, which are abundant in Earth’s crust but challenging to extract and primarily sourced from overseas, serve a vital function in modern technology, such as smartphones, electric cars, wind turbines and even in defense technologies like missiles and radar systems. The newly funded project will help to establish a 100% domestic supply chain, reducing U.S. reliance on foreign suppliers.

The project, led by Sarma Pisupati, professor of energy and mineral engineering, chemical engineering and director of Penn State’s Center for Critical Minerals, is one of four projects selected in the latest round of $17.5 million funding focused on critical minerals from the DOE. The work builds on a previous DOE-funded project to design, build and test a modular pilot-scale research and development unit intended to recover rare earth elements and other critical minerals from Pennsylvania acid mine drainage streams and other environmental sources.

“Pennsylvania is leading the way to our clean energy future with each new and innovative development,” said U.S. Senator Bob Casey (D-PA), who helped secure funding for the previous work through a congressionally directed spending initiative. “Thanks to this nearly $5 million federal investment, Penn State can continue its important work on critical mineral extraction and production from acid mine drainage, cleaning up Pennsylvania’s waterways and helping our nation outcompete China in producing elements that are in increasingly high demand in industries ranging from energy to defense to medicine.”

Rare earths and other critical minerals and materials are key to our nation’s defense and to U.S. manufacturing of clean energy technologies such as solar panels, wind turbines, electric vehicles and hydrogen fuel cells, Pisupati explained. The United States currently imports more than 80% of its rare earth elements from offshore suppliers.

“The two main goals of this project are to reduce the net import reliance on critical minerals and to help clean up the environment,” Pisupati said. “We want to demonstrate a 100% domestic supply of critical minerals that are essential for the United States’ economy. Thousands of abandoned mines spew out acid mine drainage, and we want to remove the critical minerals from this waste — we are taking waste and turning it into a treasure. This can help reduce the taxpayer money needed for cleanup and help solve a national security problem.”

The project, named Alliance for Critical Mineral Extraction and Production from Coal-Based Resources for Vitality Enhancement in Domestic Supply Chains — or ACME-REVIVE — is a collaborative effort with industry leaders, Rare Earth Salts Separations and Refining, LLC, Aqua Metals, Inc., General Electric Research and an academic partner, the University of Virginia.

“Extracting and recovering rare earth elements and other critical materials from coal, coal wastes and coal by-products has the potential to catalyze regional growth and create jobs,” said Lee Kump, the John Leone Dean in the College of Earth and Mineral Sciences. “This project will also help remediate long-standing environmental problems and help the country meet its needs for critical minerals for use in an advanced, technology-driven society.”

Specifically, the researchers aim to extract and concentrate high purity, mixed rare earth oxides from domestic coal-based acid mine drainage, or the acidic water flowing from coal mines, and clays. They also plan to separate at least five individual high purity rare earth oxides — or acids — at approximately 90% to 99.99% purity from the drainage. In addition, they aim to purify five individual or binary rare earth metals at a purity of approximately 99.5% to 99.8% and an additional five approximately 90% to 99% pure individual critical minerals and materials as oxides, salts or metals.

“Our robust capabilities in critical mineral technologies make Penn State a trailblazer in the initiative to centralize a domestic supply chain,” said Andrew Read, senior vice president for research at Penn State. “These efforts will ensure more stability in our technology pipeline — critical for positioning the United States as a global leader.”

The team plans to evaluate the properties of these materials for magnet and super alloy applications and produce high-grade lithium carbonate, nickel, cobalt, manganese and titanium.

“We are partnering with U.S. companies and universities to solve the critical minerals problem,” said Mohammad Rezaee, associate professor of energy and mineral engineering and Centennial Early Career Development Professor of Mining Engineering, and co-principal investigator on the project. “With our partners, we will extract these critical minerals from legacy coal mining wastes, separate, purify, make alloys, test for sustainable energy applications and conduct a techno-economic analysis.”

Other Penn State researchers on the project are Barbara Arnold, professor of practice in mining engineering, and Thandazile Moyo, assistant professor of energy and mineral engineering.

DOE’s National Energy Technology Laboratory, under the purview of DOE’s Office of Fossil Energy and Carbon Management, will manage the selected projects, including the one led by Penn State researchers.