A new use for Kentucky coal

UK researchers are studying the feasibility of extracting rare earth elements from coal for use in high-tech products such as electric cars, rechargeable batteries and smartphones.

A University of Kentucky-led research team is operating a pilot-scale processing plant in Webster County that may hold the key to mining rare components of common electronics in the heart of coal country.

Rick Honaker, a professor of mining engineering at the University of Kentucky, has been working with U.S. Department of Energy (DOE) officials to examine the feasibility of extracting rare earth elements (REE) from coal and coal byproducts. REEs are a group of 17 elements found in the earth’s crust and are used in manufacturing high-tech products such as electric cars, rechargeable batteries, smartphones, televisions and computer monitors. Currently 90 percent of the world’s REE supply originates in China, according to UK.

Honaker was first contacted by the DOE about the project in 2014 and asked to collect and analyze samples from around the country to determine where, and in what form, REEs could be obtained. In March 2016, the first 18-month design phase of the project got underway. Then in September 2017, the DOE approved the second phase of Honaker’s pilot scale project with a $6 million investment, along with an additional $1.5 million over 30 months pledged from other partners.

Construction on the Webster County plant began in April 2018, Honaker said. Running eight hours a day, the plant is now producing about 10 grams of high-purity concentrate material daily.

The process involves producing a concentrated mix of REEs from coal or its byproducts then placing them in a solution for extraction and ultimately producing a 99 percent pure REE material. After achieving hoped-for high purity levels of REEs on the first try, the project is off to a great start, said UK assistant professor Josh Werner, who designed and helped to build the pilot-scale plant along with two UK undergraduate and two graduate students, as well as contractors.

They are now moving toward a larger pilot scale, with commercialization to follow.

Honaker is now involved in another project in Hazard to build a processing plant that’s 40 times larger than the Webster County facility, in an attempt to replicate its promising results on an even larger scale. That plant is expected to be complete in 2020.

A new, domestic supply of REEs would benefit multiple industries. For example, Honaker said one electric car can contain as much as 5 kilograms of rare earth elements, and he expects demand will increase markedly over the next 10 to 15 years.

The team is finding significant amounts of lithium and cobalt in a few coal sources, Honaker said, which are important components of the batteries used in electric vehicles. Scandium, meanwhile, is mixed with aluminum as an alloy and used in aircraft to bolster strength while also helping to produce lighter components. It’s also used in everyday consumer goods like golf clubs and baseball bats.

Honaker said the successful mining of REEs can help make U.S. coal mining operations, which will bear the expense of mining them, more profitable. “Economically, it would be great if you’re actually producing coal and the rare earth elements as a byproduct of the operation,” he said.

—Shannon Clinton/University of Kentucky

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