Role of dissolved mineral species in selective flotation of smithsonite from quartz using oleate as collector

Quartz is, in most cases, the major gangue mineral found in the zinc oxide ores. Although it possesses a negative surface charge at pH 9, quartz nevertheless, reports to the concentrate with Zn in oleate flotation. In this study, it was found that quartz can be activated with Zn(II) and Pb(II) and floated with oleate in the pH regions of 9–11.5 and 6.5–10.5, respectively. In these pH regions, zinc and lead hydroxides are the stable species, and can be adsorbed on the negatively surface charge of quartz by adsorbing/precipitating. Therefore, the adsorption of the oleate on the activated quartz surface was being made possible. Furthermore, the effects of sodium silicate, sodium sulfide, sodium hexametaphosphate (SH), sodium fluoride, carboxymethylcellulose (CMC), and starch as depressants of dissolved Zn(II) and Pb(II) were also studied. The CMC was a quite adequate depressant without having adverse effect on smithsonite flotation. In order to probe the validity of the findings, zeta potential and real flotation experiments were also carried out successfully.