S.V. Pisupati
The Pennsylvania State University,
United States
Keywords: rare earths, critical minerals, acid mine drainage, pilot-scale recovery, circular economy
Summary:
The domestic supply chain for rare earth elements (REEs) and critical minerals (CMs) supports the United States’ clean energy, defense, and advanced manufacturing sectors. The project “Alliance for Critical Mineral Extraction and Production from Coal-Based Resources for Vitality Enhancement in Domestic Supply Chains (ACME-REVIVE)” aims to rebuild a fully domestic, sustainable supply chain by utilizing environmentally damaging, coal-based secondary resources through advanced extraction and refining technologies. The effort seeks to restore U.S. capacity for REE and CM production, ensuring national security and resilience of supply chains. This presentation discusses the technical program, which includes seven main components. First, source identification and feedstock characterization use analytical and microscopic methods (ICP-MS/OES, XRD, SEM-EDS, TEM) to measure REE, Li, Al, and Ti levels in acid mine drainage (AMD) and Mercer Clay. Second, pilot-scale extraction and recovery utilize patented hydrometallurgical and oxidative precipitation processes in a 10,000-gallon-per-day modular facility to produce high-purity (>90%) mixed rare earth oxides (MREOs) and CM concentrates (Co, Ni, Mn, Li). Additional unit operations—including flash heating, modified acid baking, and solvent extraction—allow for selective recovery of REEs, Li, Al, and Ti. Waste valorization strategies will transform Fe- and Al-rich residues into reusable byproducts. Third, advanced separation and purification techniques convert pilot concentrates into individually separated, high-purity (ISHP, >99%) REOs and CMs through selective leaching, staged precipitation, calcination, titration, and electrowinning, focusing on key REEs (Ce, La, Nd, Pr, Sm, Eu, Dy, Tb, Y) and CMs (Co, Ni, Mn, Li). Fourth, metal and alloy production employs molten-salt electroreduction and reduction-alloying methods to produce REE metals, master alloys, and superalloys, optimized via thermodynamic modeling and lab validation to minimize energy consumption and impurity levels. Fifth, application testing fabricates and characterizes Nd-Fe-B and SmCo permanent magnets and Co/Ni-based superalloys using recovered materials. Microstructural and magnetic performance will be benchmarked against commercial standards. Sixth, integrated techno-economic (TEA) and life-cycle analyses (LCA) evaluate environmental and economic feasibility, demonstrating reduced chemical use, emissions, and energy intensity compared with traditional mining and refining methods. Finally, project management and technology development ensure structured execution, risk reduction, and readiness for commercial deployment. Led by Penn State with industry and national lab partners, ACME-REVIVE is one of the first integrated demonstrations linking coal-based feedstocks to advanced manufacturing. The initiative turns legacy coal and AMD liabilities into vital mineral assets, promoting U.S. energy independence, industrial strength, and sustainable resource use.