Source：Forbes
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, was tapped by U.S. Department of Energy (DOE) officials to examine the feasibility of extracting rare earth elements from coal and coal byproducts. Rare earth elements, or REEs, are a group of 17 elements found in the earth’s crust that include neodymium, scandium and yttrium 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 information from UK. “We’re working on a project that obviously has a lot of national interest,” Honaker said.
Honaker, who’s taught at UK for the past 19 years, 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-long 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.
Rick Honaker, left, a professor and chair of mining engineering in the UK College of Engineering, talks with assistant research professor Wencai Zhang, Ph.D. student Alind Chandra and postdoc Honghu Tang.
Equipment was purchased and construction on the Webster County plant had begun by April 2018, Honaker said. Running eight hours a day, the plant is producing about 10 grams of high-purity concentrate material daily, he said. “I think that’s a significant achievement, and people are doing a lot of research and a lot of trials and effort to get to this point,” Honaker said.
Others working on the project include UK assistant professor Josh Werner and researcher Wencai Zhang, Virginia Tech’s Roe-Hoan Yoon, Gerald Luttrell and Aaron Noble and, from West Virginia University, Qingqing Huang.
The process involves producing a concentrated mix of REEs from coal or its byproducts, then, in a lab, 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 Werner, who designed and helped to build the pilot-scale plant along with two UK undergraduate and two graduate students, as well as contractors. He said the plant can process liquids, solids and precipitates.
With a background in industrial engineering, Werner said he relates to students as more of an engineering lead than a teacher, striving to show them the value of their work toward becoming skilled, knowledgeable and talented employees in their respective future careers. He said this research group has focused on taking a theory and applying it in experiments toward reaching the pilot phase. They are now moving toward a larger pilot scale, with commercialization to follow. “It’s been wonderful for our students to see how well it all ties together in a stream,” he said.
Honaker is now involved in another project in Hazard, Kentucky, to build a processing plant that’s 40 times larger than the Webster County one, in an attempt to replicate its promising results on an even larger scale. That plant is expected to be completed in 2020.
Honaker said REEs are also found in sand in some areas of Florida and Georgia, but they are far more difficult to extract from sand than from coal. 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. “In a coal resource in eastern Kentucky, the coal cleaning waste material has been valued at over $100 per ton, based solely on the amount of lithium present,” he said. 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 used in military aircraft, Honaker said, but also 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.