From beakers to bench, UND snares second federal grant to extract rare earth elements from lignite coal
Lignite coal was once considered a low-demand coal.
Times have changed.
Lignite contains a high percentage of rare earth elements, which are used in cell phones, electronics, and materials for defense.
“Ninety percent of rare earth element production is in China,” said Steve Benson, associate vice president for research with the Energy & Environmental Research Center and professor of chemical engineering, who with Dan Laudal recently received a federal grant to find a way to extract those elements from lignite. “China controls mining and production as well as the whole value chain to produce the elements. We have an opportunity to use North Dakota lignite coal to break that chain.”
And that opportunity could mean a whole new industry for North Dakota, they said.
“Rare earth elements are critical to military applications, and we need a domestic source of them,” said Laudal, manager of major projects at the Institute for Energy Studies. He added that their content in lignite is high, and may be more easily extracted than from other sources.
That – and UND’s reputation for energy research – is why the federal government recently awarded $2.75 million to UND to find an economically feasible way to extract those elements from lignite. Industry partners, UND and NDUS have also chipped in $777,500 for a total project of $3,527,500.
“The University of North Dakota is on the forefront of technology and innovation, especially when it comes to finding a viable future for coal,” said Sen. Heidi Heitkamp, who announced the funding.
Optimizing the chemistry
The UND project is one of four in the nation funded for this second phase of the research, which will scale up extraction from laboratory beakers to 55-gallon drum tanks. The Institute for Energy Studies at the College of Engineering and Mines and the EERC will work jointly on the project.
UND also received funding for the first phase, a lab process which looked at the characteristics of the “feed stock,” or coal, and tested the recovery process, as well as the economic feasibility of recovery. That phase used 60-gram batches of coal with solvents to extract and concentrate the rare earth elements.
“Phase 2 will scale it up and process 10 kilograms per hour of lignite in a continuous process,” said Benson and Laudal. “It’s the next step before a pilot program. We go from lab to bench, then hopefully a pilot program, processing two and a half tons per hour. We’re trying to optimize the chemistry and then integrate the entire process.”
“Lignite is unique, and has huge advantages over competing sources,” Benson said. “The rare earth elements in lignite can be more readily recovered. It’s simpler and more environmentally friendly than other sources.”
“The rare earth mineral content in lignite is exceptionally high, as high as any other coal in the U.S.,” said Laudal. And you can still use the coal. “In addition to recovering the rare earths, our process also cleans the coal, and products such as activated carbon can be made.” He added that extracting the elements lowers the ash content of coal and makes it burn more efficiently. “That’s a key benefit. Two products – the rare earth elements and a better, higher-value coal.”
If the phase 2 project succeeds – and the researchers believe it will – plans for a pilot plant are already in the works.
It would be located at Valley City State University’s new steam plant, which would harvest the rare earth elements, heat the university, and produce activated carbon, which is used to purify water.
“That’s a nice scale for a pilot project,” Laudal said, adding that the North Dakota University System is supporting the project.
Rare earth elements include europium, dysprosium, erbium, terbium, neodymium, holmium, scandium, lutetium, and yttrium, among others. They’re used in everyday items, such as computer memory chips, rechargeable batteries, DVDs, cell phones, catalytic converters, magnets, fluorescent lighting, electronics and more. Critical for defense, they are used by the military in night-vision goggles, precision-guided weapons, GPS, and electronics. They are also essential for green energy applications such as wind turbines and hybrid/electric vehicles.
Extracting those elements from coal is cutting edge, Benson said. He published a paper in 1983 on his research, which found rare earth elements in coal.
“That was just curiosity,” Benson said. “I wanted to see if they were there, and they were.” He added that there were fewer uses for the elements then, and the technology wasn’t available to extract them. It’s only in the last five to 10 years that extraction research has taken place.
Laudal said they’re confident about their extraction process, which is proprietary. The challenging part will be meeting the timeline of producing results in just 18 months.
Project sponsors include the U.S. Department of Energy, the N.D. Industrial Commission Lignite Research Program, Great River Energy, North American Coal, Minnkota Power, and Great Northern Properties. The project also has support from the UND College of Engineering & Mines and NDUS.