Uncommon earth components might be extracted from coal waste

In Appalachia’s coal country, researchers envision turning toxic waste into treasure. Pollution left by abandoned mines is an untapped source of rare earth elements.

rare earth is a Valuable set of 17 elements Needed to make everything from smartphones and electric cars to fluorescent light bulbs and lasers.China near monopoly on rare earth production as global demand soars – U.S. only one active mine — There is interest in finding alternative sources such as step up recycling.

Extracting rare earths from coal waste offers a two-in-one deal: By recycling the metals, you also help clean up pollution.

Long after coal mines close, they leave a dirty legacy. When some rocks left over from mining are exposed to air and water, sulfuric acid forms and draws heavy metals from the rocks. This acidic soup can pollute waterways and harm wildlife.

Recovery of rare earths from so-called acid mine wastewater Paul Ziemkiewicz, director of Morgantown’s West Virginia Water Institute, acknowledged that growing demand for metals cannot be met alone. But he points to several benefits.

Unlike ores mined from typical rare-earth mines, drainage is rich in the most-demanded rare-earth elements. In addition, extraction from acid mine wastewater does not produce radioactive waste, which is often a by-product of rare earth mines, which often contain uranium and thorium as well as rare earth elements. From a practical point of view, existing acid mine wastewater treatment facilities can be used to collect rare earths for processing. “Theoretically, you could start production tomorrow,” Ziemkiewicz said.

Ziemkiewicz and colleagues estimate that nearly 600 metric tons of rare earth elements and cobalt, another metal in high demand, could be produced annually from the hundreds of sites that already treat acid mine drainage.

A pilot project in West Virginia is currently extracting and concentrating rare earths using material recovered from acid mine drainage treatment sites.

If such a plan proves feasible, Ziemkiewicz envisions a future in which cleanup sites haul their rare earths to a central facility for processing, where the elements are then separated. Economic analysis shows that this is not a get-rich-quick scheme. But, he said, that may be enough to cover the cost of treating acid mine wastewater.