Optimized Flotation of Zinc Oxide Ores: Synergistic Effects of Mixed Collectors and Desliming

The flotation of zinc oxide ores presents significant technical challenges due to their complex surface chemistry and fine particle size. This study investigates the flotation behavior of a zinc oxide ore (۱۳–۱۴% Zn, ۳–۴% Pb) from the Barmalek deposit using different collector systems—potassium amyl xanthate (KAX), cocoalkylamine acetate (Armac C), and a mixed collector system. Comprehensive mineralogical and liberation analyses confirmed the oxide-dominated nature of the ore and the presence of slime-generating fractions, which negatively affect flotation performance. Systematic flotation experiments were conducted using Taguchi design arrays (L۸, L۱۲, L۱۸) to evaluate the effects of various parameters, including reagent dosages, pH, and flotation time, both with and without desliming. Results showed that KAX or Armac C alone provided limited recovery and selectivity. In contrast, the mixed collector system significantly enhanced zinc recovery and concentrate grade, particularly when combined with desliming. Under optimized conditions—pH ۱۱, Na₂S ۲۸۰۰ ppm, starch ۱۰۰۰ ppm, sodium silicate ۴۰۰ ppm, flotation time ۴ minutes, xanthate ۵۰۰ ppm (stage ۱), xanthate ۴۰۰ ppm (stage ۲), and Armac C ۳۰۰ ppm—zinc recovery reached ۸۴.۳% and concentrate grade exceeded ۴۲%, while calcium recovery was minimized to ۱۳.۸۵%. Validation experiments confirmed the model predictions, although actual recoveries slightly decreased after accounting for slime losses. The findings demonstrate the synergistic potential of mixed collectors and highlight the critical role of desliming and reagent optimization in improving the flotation of refractory zinc oxide ores.

کلیدواژه ها:

Zinc oxide flotation ، Mixed collectors ، Xanthate ، Armac C ، desliming ، Taguchi design ، Reagent optimization