Synergistic adsorption mechanism of sodium dibutyldithiocarbamate and ammonium dibutyldithiophosphate on chalcopyrite surface and its response to flotation separation of Cu–Fe sulfide minerals

Conventional collectors based on xanthate utilized in the flotation process for separating Cu–Fe sulfide minerals are hindered by issues such as low selectivity, the need for large dosages, and environmental implications. This study investigated the synergistic adsorption behavior of a binary collector system composed of sodium dibutyldithiocarbamate (SD) and ammonium dibutyldithiophosphate (ADD) on chalcopyrite surfaces. Micro-flotation tests indicated that the SD/ADD mixture significantly improved flotation performance compared to the individual collectors. With a total concentration of the collector at 5 × 10⁻ 5 mol/L and a molar ratio of ADD to SD set at 2: 3, chalcopyrite recovery reached 94.64 %, with an increase of approximately 33 % over that achieved with a single collector. Surface characterization results confirmed that SD and ADD co-adsorb onto chalcopyrite through both physical and chemical interactions, forming a hydrophobic surface layer. In contrast, under lime-treated suppression conditions, the adsorption of the mixed collectors on pyrite was effectively inhibited. Molecular dynamics simulations further revealed that SD and ADD co-adsorb onto the (112) crystal plane of chalcopyrite. These findings confirm the combined influence of SD and ADD in improving the flotation efficiency of chalcopyrite and present a potential reagent system for the flotation separation of Cu–Fe sulfide minerals.