Rare-earth recovery

Abstract

Cover story The U.S. coal industry is facing tough times. Demand for coal is dwindling, and the industry is under fire for polluting streams and rivers with coal ash and acid mine drainage. But in that waste, and in some cases in the coal itself, are valuable rare-earth elements that may be readily recovered. If researchers can figure out how to extract them economically, sales of rare earths could help pay for some of the cleanup costs now borne by the coal industry and several coal-mining states. Demand for rare-earth elements, which include the lanthanides plus scandium and yttrium, has ticked upward over the past few decades. The long list of high-tech products that rely on rare earths include cell phones, flat-screen TVs, electric cars, wind turbines, satellites, defense aircraft, and high-performance magnets. In 2015, global demand for rare-earth elements was 149,000 metric tons per year, according to Mary Anne