Enhanced sulfidization flotation mechanism of smithsonite in the synergistic activation system of copper–ammonium species

• Copper–ammonium species exhibited superior activation performance than individual copper ions. • The activity of sulfidization products on smithsonite surfaces enhanced after activation with copper–ammonium species. • Addition of copper–ammonium species significantly enhanced the surface hydrophobicity of smithsonite. • Smithsonite floatability greatly increased in the synergistic activation system of copper–ammonium species. Copper–ammonium species were introduced in this work to improve the surface sulfidization and flotation performance, and the mechanism was revealed by solution composition determination and surface measurements. Results showed that copper–ammonium species exhibited superior activation performance compared to individual copper ions, and more copper ions were transferred onto the smithsonite surface to increase the mineral surface reactivity with sulfide and xanthate species. Compared with the individual activation system of copper ions, a superior sulfidization of smithsonite was obtained in the synergistic activation system of copper–ammonium species. The activation of smithsonite surfaces with copper–ammonium species not only increased the content of copper sulfide species, but also enhanced the activity of sulfidization products on the surface of smithsonite. Accordingly, a greater amount of xanthate species adsorbed on the surface of smithsonite, and the surface hydrophobicity significantly was enhanced after smithsonite was activated with copper–ammonium species. Compared with treatment in the direct sulfidization system, the flotation recovery of smithsonite increased by approximately 30% under the optimum flotation conditions after treatment in the synergistic activation system of copper–ammonium species. The research results provide a potential technology for promoting the efficient recovery of zinc oxide minerals through sulfidization xanthate flotation.