Mechanism, kinetics and process assessment of efficient extraction of valuable metal from nickel sulfide ore by (NH4)2S2O8 direct oxidative leaching

A clean and efficient process for the direct extraction of valuable metals from low-grade nickel sulfide ore through oxidative leaching with (NH 4 ) 2 S 2 O 8 under atmosphere pressure was proposed to address the growing demand for nickel and cobalt in the new energy industry. The effects of four key parameters on the metal leaching rates were systematically investigated. Characterization techniques, including XRD, SEM and EDS, were employed to analyze phase transformations during the leaching process. Under optimized conditions, approximately 96.5% of nickel, 95.5% of cobalt and 65.2% of copper were successfully extracted. The kinetics of the leaching process was explored to identify the controlling mechanisms of nickel, cobalt and copper dissolution, establishing activation energies and kinetic equations for each metal. The cleanliness and efficiency of this method were confirmed through comparisons with other extraction processes for nickel sulfide ore.