A. Noble
Virginia Tech,
United States
Summary:
Over the last decade, several US federal and international agencies have developed policies, investment strategies, and research programs to promote rare earth element (REE) and critical mineral (CM) production while building more sustainable supply chains. One significant component of these programs is supply diversification, including the development of technologies and processes needed to utilize unconventional and secondary REE resources. In the US, research and development efforts since 2016 have targeted deleterious mining wastes, including acid mine drainage, coal refuse, coal combustion byproducts, mine tailings, and others, as potential sources of critical REEs and non-REE CMs. This approach provides a pathway to recover REEs while addressing legacy environmental wastes; however, the specific REE mineralogy and low-grade concentrations in these materials often entail significant technical and economic challenges. This presentation will explore the process development efforts from several case studies and specifically highlight one promising route, namely the recovery of REE/CM from acid mine drainage. Over the past seven years, researchers have successfully developed REE-from-AMD recovery technologies and successfully matured the technology from the laboratory to the field. To date, these efforts have culminated in high TRL pilot and demonstration scale projects, proving the technical feasibility of the approach and providing validation of the overall economic potential. In addition, these research, development, and deployment efforts are providing technical training and educational opportunities for a next-generation REE/CM workforce. The presentation will discuss findings from this program and identify opportunities for future research and development, including crosscutting technologies with both conventional and unconventional applications.