Mine Tailings Valorization by Electrochemically Stimulated Mineralization from Mildly Acidic Conditions

Area of Science:

• Environmental Chemistry
• Electrochemistry
• Materials Science

Background:

• Mine tailings often contain supernatant water with dissolved carbonates.
• Acidic conditions in mine tailings can lead to environmental challenges.
• Carbon dioxide (CO2) capture and utilization is a key area for environmental remediation.

Purpose of the Study:

• To develop a high-efficiency electrochemical process for calcium carbonate (CaCO3) precipitation.
• To investigate the selective mineralization of CaCO3 from mine tailing supernatant.
• To explore the potential for CO2 utilization and mine tailings valorization.

Main Methods:

• Electrochemical pH control was employed to induce carbonate speciation and precipitation.
• Applied potentials between -1.4 and -1.6 V vs Ag/AgCl were utilized.
• Experiments were conducted using both synthetic and real mine tailing water.

Main Results:

• Achieved high efficiency: >1 mol CaCO3 precipitated per mol of electrons.
• Demonstrated tunable product morphology and polymorph selectivity (calcite, vaterite) via applied potential.
• Confirmed selective calcite precipitation from real mine tailings water, even with interfering ions like sulfate.

Conclusions:

• The electrochemical process is effective for CaCO3 mineralization from mine tailing supernatant.
• This method provides a viable route for coupling CO2 utilization with mine tailings valorization.
• The process shows promise for environmental remediation and resource recovery.