Critical minerals are vital components of our consumer goods, national defense, and emerging green-energy technologies; they are part of everyday life from smart phones to electric vehicles. The U.S is heavily dependent on imports for an adequate supply.
Penn State researchers are looking for ways to use Pennsylvania’s coal mine waste as a domestic source for these materials and reduce environmental pollution at the same time.
By integrating Penn State’s interdisciplinary expertise and its world-class facilities, The Center for Critical Minerals is a catalyst for a new critical mineral industry built on environmental remediation and domestic production.
Sarma Pisupati, director of the Center for Critical Minerals at Penn State and professor of energy and mineral engineering, College of Earth and Mineral Sciences
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Can Pennsylvania’s mine waste provide a domestic supply of critical minerals?
“By modifying existing treatment processes, we can address multiple problems: getting the material we need for national security and remediating long-standing environmental problems at the same time.”
Finding a domestic supply of critical minerals
A sustainable supply of critical minerals is vital to the future of the U.S. economy.
In addition to green-energy uses, critical minerals are needed for cell phones, computers, battery technology, semiconductor chips, electric vehicles, and many other applications in the high tech, energy, and defense sectors. Currently, the U.S. depends almost entirely on imports of these minerals.
“We are highly dependent on other countries for both production and processing,” said Sarma Pisupati, director of the Center for Critical Minerals at Penn State, and professor of energy and mineral engineering.
The U.S. Geological Survey (USGS) lists 50 minerals as critical to the U.S. economy and national security. That number includes rare earth elements and battery metals, among others. According to USGS, the U.S. imported almost all the rare earth elements it used in 2018, and Department of Energy figures show over 50% import reliance for the remaining critical minerals, and 100% reliance for 14 of them.
The U.S. Department of Energy tapped Penn State to lead a regional consortium to assess potential resources, develop strategies to recover these materials, and identify potential gaps in the supply chain as part of a national effort to ramp up domestic production of critical minerals.
Recovering critical minerals from waste
Pennsylvania’s legacy as a coal-mining state could turn a problem into a part of the solution.
Decades of industrial mining have left behind literal mountains of waste across the Commonwealth. Coal byproducts like mine tailings, coal ash, sludge ponds, and acid mine drainage are an ongoing environmental concern. However, researchers have discovered significant quantities of critical minerals locked inside those waste streams. Developing a process to extract minerals that is both environmentally friendly and financially realistic requires bold advances in mineral processing.
Mine tailings, acid mine drainage, fly ash, and even a large clay deposit in central Pennsylvania are all being considered as viable sources of critical minerals.
The Center for Critical Minerals has found a new method to extract critical minerals from acid mine drainage that simply modifies the process already being used for environmental treatment. By applying this new treatment, some critical minerals and rare earth elements separate from the waste. This process captures the valuable materials to be purified and sold, while cleaning up polluted water and Pennsylvania’s environment.
“We’re also looking at electronic waste recycling,” Pisupati said. “Our approach has been to try to recover multiple metals from a given waste stream in order to make the process economically feasible.”
Creating a new critical mineral industry
The goal of the Center for Critical Minerals is to integrate Penn State’s wide-ranging expertise and its world-class facilities in support of efforts to establish domestic production of these minerals.
While obstacles are ahead, Pisupati said, the time is ripe to scale-up some of the novel extraction technologies that have shown promise in the lab. The center has attracted $2.1 million in federal funding for a demonstration facility “to integrate all that we are learning and show potential investors that this can actually work,” he said.
There are unique challenges involved in dealing with secondary mineral sources, Pisupati acknowledged. But there is also strong precedent at Penn State for the kind of academic-industrial partnership that is now taking shape, he said.
In the 1980s, when the U.S. power industry was deregulated, Penn State research played a key role in the emergence of the independent power industry, Pisupati said, enabling the use of coal mine waste as fuel and thereby also effecting substantial environmental remediation across the state.
“We have had success at this scale,” he said. “We changed an industry. And we’re ready now to make that kind of impact in critical minerals.
“The need is urgent, and Penn State is ready and able to help.”
“Mission Critical,” by David Pacchioli, originally published in the Fall 2022 issue of Research/Penn State magazine, describes the work of Penn State’s Center for Critical Materials.
The Center for Critical Materials, directed by Sarma Pisupati, was formed by the College of Earth and Mineral Sciences, taking advantage of more than 70 years of interdisciplinary research expertise. Today, its research core includes over 25 faculty from departments across Penn State, including geosciences, energy and mineral engineering, materials science and engineering, chemistry, chemical engineering, and energy business and finance.
Penn State is leading a regional consortium to assess and catalog critical mineral resources in Pennsylvania and surrounding states, develop strategies to recover these materials, and identify gaps in the supply chain. The Consortium to Assess Northern Appalachian Resource Yield, or CANARY, is part of a national effort to ramp up domestic production by the U.S. Department of Energy.