Researchers at Penn State University developed a two-stage treatment process for acid mine drainage that enabled them to recover higher concentrations of rare earth elements using smaller amounts of chemicals than previously possible.
In a paper published in the Chemical Engineering Journal, the scientists say that AMD from coal mining operations in Appalachia represents a promising domestic source of REE because it often contains high concentrations of the minerals and because it is already being collected and treated due to environmental concerns.
This residue is produced when pyrite rock — iron sulphide — unearthed by mining activity interacts with water and air and then oxidizes, creating sulfuric acid.
The acid then breaks down surrounding rocks, causing toxic metals to dissolve into the water. Traditional treatment methods involve collecting the AMD in ponds and adding chemicals to neutralize the pH.
For the rest of this article: https://www.mining.com/scientists-find-efficient-way-to-extract-ree-from-acid-mine-drainage/