Influence of important factors on flotation of zinc oxide mineral using cationic, anionic and mixed (cationic/anionic) collectors

In this study, the influences of important factors on smithsonite flotation are investigated. Dosages of sulphidizing agent and collector, desliming prior to flotation and the use of sodium hydroxide instead of sodium carbonate as the pH regulator are essential to the effective recovery of smithsonite in cationic flotation. The appropriate temperature for flotation was found to be 30–40 °C. Sodium hexametaphosphate (SH) and sodium silicate had the greatest selectivity between smithsonite–calcite and smithsonite–quartz, respectively. The results of oleic acid flotation showed that the grade and recovery of zinc were relatively low in comparison with the sulphidization-cationic flotation method. Despite using sodium silicate and SH as depressants in oleic acid flotation, flotation was not selective. Flotation using mixed collectors (Armac C + Potassium Amyl xanthate) showed promising results. The ratio of the mixed collectors and the sequence of addition of mixed collectors were important criteria in attaining true mixed collector flotation.