Mine Tailings Valorization by Electrochemically Stimulated Mineralization from Mildly Acidic Conditions.

Abstract

This study presents a high-efficiency electrochemical process for the mineralization of calcium carbonate (CaCO₃) from mildly acidic mine tailing supernatant water. Electrochemical pH control was used to promote carbonate speciation and precipitation from CO₂-saturated solutions, achieving >1 mol CaCO₃ precipitated per mol e^- at applied potentials between -1.4 and -1.6 V vs Ag/AgCl. Product morphology and polymorph selectivity were tunable via applied potential, yielding calcite and vaterite phases. Experiments using real mine tailings water confirmed selective calcite precipitation, despite the presence of sulfate and other trace elements. These results highlight a viable route for coupling CO₂ utilization with mine tailings valorization.