Enhanced sulfurization has always been the focus of research on the flotation of copper oxide minerals. In this study, combined ammonium-amine salts were innovatively applied to improve the sulfurization of azurite. Flotation tests were carried out to evaluate the promoting effect of ammonium-amine co-activation on the sulfurization-xanthate flotation of azurite, and the microstructure evolution of sulfurized products was investigated to reveal the mechanism underlying this promoting effect. Compared with single ammonium (amine) salt activation, ammonium-amine co-activation improved the floatability of azurite to a greater extent, i.e., the flotation recovery increased by over 4 percentage points. ToF-SIMS, ICP-OES, FESEM-EDS, AFM, XRD, and UV-vis analyses indicated that ammonium-amine co-activation combined the advantages of inorganic ammonium for buffering pH and organic amine for copper ion complexation, thus promoting the growth of sulfurized crystal products (covellite) and enhancing the adhesion stability of sulfurized products on azurite. Therefore, increasing amounts of copper sulfide components were generated under the ammonium-amine-Na2S system, promoting the adsorption of additional xanthate on azurite. This study provides theoretical support for the application of combined ammonium-amine salts for the sulfurization flotation of copper oxide.
Keywords: ammonium–amine co-activation; azurite; microstructure; sulfurization flotation; sulfurized products.