Title: Eco-Efficient Oxidative Leaching of Zinc Sulfide Concentrates Using Manganese Dioxide: A Thermodynamic and Process Analysis
Authors: Khojiev Sh.T., Kholikulov D.B., Khaydaraliev Kh.R., Javliyev S.S., Movlanov A.S.
Volume: 9
Issue: 10
Pages: 163-171
Publication Date: 2025/10/28
Abstract:
This study investigates the thermodynamic and kinetic feasibility of oxidative selective leaching of zinc sulfide (ZnS) using manganese dioxide (MnO?) as an oxidizing agent in a sulfuric acid medium. Based on the calculated Gibbs free energy (?G) and equilibrium constant (K) values for three possible reaction pathways, the process was found to be most thermodynamically favorable within the temperature range of 45-55 °C. The combined oxidation-acid leaching reaction (ZnS + MnO? + 4H? ? Znē? + Mnē? + S + 2H?O), maintains negative Gibbs free energy values (?G ? -197 kJ/mol) across this range, confirming its spontaneous nature and high thermodynamic stability. The process ensures efficient dissolution of zinc while producing elemental sulfur as a valuable by-product. Subsequent purification of manganese through ozone oxidation allows for selective MnO? regeneration, supporting a cyclic and resource-efficient operation. The proposed approach not only minimizes zinc losses in solid residues but also enriches the acid-insoluble fraction with precious metals such as gold and silver, enhancing the economic and environmental performance of the overall hydrometallurgical process. The results provide a reliable scientific basis for developing an energy-efficient, eco-friendly, and cost-effective technology for the complete hydrometallurgical processing of zinc sulfide concentrates.