Electrochemical conversion of sulfide mineral-containing mine waste for energy and resource recovery using fuel cell technology

Sulfide minerals present in mine waste, upon oxidation by oxygen and water, can lower the pH, leading to increased metal solubility. This study focuses on mine waste containing sulfide mineral, utilizing fuel cell technology to recover valuable resources. The aim is to explore the potential conversion of mining by-products into valuable energy and resources, addressing environmental impact and transforming mining waste into a valuable asset. The electrochemical oxidation of pyrite (FeS₂) (ΔG⁰ = -27.15 kJ/mol) is induced through electrode installation, with the reaction facilitated by employing electrodes. In this process, pyrite acts as an electron donor, and oxygen, mediated by the electrode, acts as an electron acceptor. The cathode is designed to induce the oxidation of pyrite (Pyrite→Fe³⁺), while the anode, exposed to oxygen in the air, promotes the reduction of oxygen (O₂→H₂O). Pyrite (150-250 μm in diameter) was placed in the anode cell containing 125 mL of anolyte (distilled water adjusted to pH 2.0 with hydrochloric acid), and the cathode cell was exposed to air. After 4 weeks of reaction 23 mg of pyrite was dissolved leaching 0.73 mM of Fe, and generating 4.1616×10⁻⁷ W of power. In the further study the fuel cell technology will be applied to utilize sulfidic mining residues (XRD analysis result: FeS_1.6Se_0.4 42%, FeS₂ 14%, Mg₂CaWO₆ 12%, etc.), generated during the ore beneficiation process at a tungsten mine in Yeongwol, Gangwon Province, South Korea, for the recovery of energy and valuable metals.