Synergistic activation of smithsonite with copper-ammonium species for enhancing surface reactivity and xanthate adsorption

Copper ions (Cu2+) are usually added to activate the sulfidized surface of zinc oxide minerals to enhance xanthate attachment using sulfidization xanthate flotation technology. The adsorption of Cu2+ and xan-thate on the sulfidized surface was investigated in various systems, and its effect on the surface hydrophobicity and flotation performance was revealed by multiple analytical methods and experiments. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) characterization demonstrated that the adsorption of Cu2+ on sulfidized smithsonite surfaces increased the active Cu-S content, regardless of treatment in any activation system. The sulfidized surface pre-treated with NH4+-Cu2+ created favorable conditions for the adsorption of more Cu2+, significantly enhanc-ing the smithsonite reactivity. Zeta potential determination, ultraviolet (UV)-visible spectroscopy, Fourier transform-infrared (FT-IR) measurements, and contact angle detection showed that xanthate was chem-ically adsorbed on the sulfidized surface, and its adsorption capacity in various systems was illustrated from qualitative and quantitative aspects. In comparison to the Na2S-Cu2+ and Cu2+-Na2S-Cu2+ systems, xanthate exhibited a higher adsorption capacity on sulfidized smithsonite surfaces in NH4+-Cu2+-Na2S- Cu2+ system. Hence, activation with Cu2+-NH4+ synergistic species prior to sulfidization significantly enhanced the mineral surface hydrophobicity, thereby increasing its flotation recovery.(c) 2023 Published by Elsevier B.V. on behalf of China University of Mining & Technology. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).