Rare earths extracted from coal mining by-products

Acid mine drainage sludge drying cells at a mine in Upshur County, West Virginia. Photo by West Virginia University.

Researchers from West Virginia University and the National Energy Technology Laboratory are working on a project aimed at extracting rare earth elements from the acid mine drainage found at various coal mine sites in the United States.

Besides pioneering a new and less expensive method to recover the 17 elements, the scientists want to bolster domestic supply to reduce the current dependence on Chinese imports. Rare earth elements are used in cell phones, rechargeable batteries, DVDs, GPS equipment, medical equipment and various defense applications.

In their quest, the academics did a preliminary sampling and discovered that minerals such as candium, yttrium and neodymium become soluble in acidic environments, which means that they can concentrate near mine sites. With this information, they developed a potential feedstock for a refinery they wanted to build at the university and analyzed that initial product. They found that about 45 per cent of the rare earths in acid mine drainage are in the heavy categories, which are the more valuable categories.

Besides allowing them to “harvest” RRE, their initiative would also positive effects when it comes to cleaning up coal-polluted streams.

The researchers expect to start extracting rare earth elements from sludge, drainage sites, and groundwater, refining them and taking them to market in a couple of years once their pilot program is completed.


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