Determination of the optimum conditions for zinc extraction from ore containing sphalerite by HCl solutions

The Taguchi method has been used to determine optimum conditions for the zinc and iron extraction from ore containing sphalerite by HCl solutions. After determining the important parameters in extraction efficiency, an experimental series with two steps was carried out. The optimum conditions for the first series of experiments were found to be reaction temperature 90°C, solid-to-liquid ratio 0.091 g/mL, acid concentration 25 mass%, particle size -100+200 mesh, stirring speed 300 rpm and reaction time 120 min. Under these conditions, zinc extraction efficiency from ore was approximately 60%. The optimum conditions for the second series of experiments were found to be reaction temperature 90°C, acid concentration 32.5 mass%, solid-to-liquid ratio 0.1 g/mL, and reaction time 180 min. Under these conditions, zinc extraction efficiency from the ore was approximately 100%. Alternative working conditions reducing the total cost were also determined.