Acidic Water Pollution Cleanup and Community Economic Development through Domestic Production of Critical Minerals for National Security

The objective of this effort is to design and install a modular, pilot-scale test unit to process 10,000 gallons per day (gal/day) or 7 gallons per minute (gpm) of raw Acid Mine Drainage (AMD) to recover rare earth elements (REE), iron (Fe), and critical minerals (CMs) such as aluminum (Al), cobalt (Co), and manganese (Mn). This test unit uses a three-stage process including (1) acid-less leaching for AMD instead of caustic chemicals, (2) selective recovery of REEs, CMs, and Fe from pregnant leaching solutions using environmentally friendly chemicals such as Na2CO3, and (3) chemical-free extraction of Co and Mn to obtain high-purity products which will render the discharge water harmless to meet the environmental regulations. Additional smaller modular units may be developed to process AMD sludge and to examine the technical feasibility of recovering lithium (Li) from clay. The test unit will help test various feedstocks and optimize operating conditions, generate mass and energy balances and chemical consumption, and characterize all streams necessary for the techno-economic analysis and scale-up. Furthermore, the operational data, development of required scale-up parameters, and experience from the proposed modular pilot-scale test unit will potentially reduce investment risk.