F-LLX: Flotation-Liquid Liquid Extraction

Battelle Memorial Institute, Columbus, Ohio

As oil prices increase, the demand for coal rises rapidly. But coal mining often has negative effects on the surrounding environment. There are hundreds of contaminated mine sites in the U.S., and 144 in Pennsylvania alone. That was the impetus behind the development of F-LLX: Flotation-Liquid Liquid Extraction by researchers at Battelle Memorial Institute, Columbus, Ohio. F-LLX is an integrated process to purify acid mine drainage (AMD) water while simultaneously extracting the impurities and converting them into valuable co-products. The process mixes a tailored extractant liquid phase with the AMD water that is contaminated with toxic yet useful cations such as iron, aluminum, and sulfate. The extractant is formulated to pull these contaminants rapidly from the AMD and then cleanly separate, leaving purified water. The now-loaded extractant is then processed to recover the former pollutants as products such as ferrous sulfate and potassium sulfate. The regenerated extractant is then recirculated via a closed loop to continuously purify more AMD water. F-LLX effectively purifies AMD water in mild operating conditions, in simple equipment, without generating any significant waste stream.