Selective flotation separation of chalcopyrite and molybdenite remains challenging because of their similar surface properties. In this study, a cooperative adsorption mechanism for heterocyclic flotation depressants is discussed, in which selective depression is proposed to arise primarily from thiol-derived coordination interactions together with secondary contributions from molecular rigidity and π-electronic stabilization. 2,5-Dimercapto-1,3,4-thiadiazole (DMTD) was selected as a model molecule to assess this hypothesis. Density functional theory calculations and interfacial experiments indicated that its thiol donor groups, rigid heterocyclic backbone, and conjugated electronic structure promote strong coordination with surface Cu sites, assist adsorption stabilization, and favor a flat adsorption configuration. Flotation experiments showed that DMTD efficiently depressed chalcopyrite at an ultralow concentration of 7.0 × 10 –5 mol/L, producing a recovery difference of 60%. The results provide mechanistic insights into the structural factors governing selective chalcopyrite depression.
Z et al. (Thu,) studied this question.