This study is the the recovery of lead from the bioleaching residue of gooshfil ore by chloride leaching method. Zinc bioleaching residue contained 28% Pb, 9.6% Zn and 6.4% Fe. The lead in this residue was in the form of lead sulfate and lead sulfide. NaCl and FeCl3 were used as leaching agents and 0.5 M HCl as pH regulator. Experimental statistical dsesign of response surface methodology was used to investigate the effect of key parameters such as temperature (50, 70 and 90 ° C), NaCl (50, 150 and 250 g / L), FeCl3 (25, 50 and 75 g / L) and leaching time (1, 3 and 6 h) on the lead recovery. According to the results of analysis of variance, temperature, NaCl and FeCl3 concentrations were the most effective parameters of lead chloride leaching process. The increasing of temperature had the most significant effect on the lead recovery. Increasing in NaCl and FeCl3 concentration increased the recovery. The results showed that the highest recovery of lead (75%) was obtained at 230 g/L NaCl, 40 g/L FeCl3 at 86 °C and 180 min. Electrochemical cyclic voltammetric analyses were also used to investigate the mechanism governing the leaching process. The results showed that increasing the temperature increased the rate of anodic oxidation in the chloride medium which could be as a result of the electrochemical behavior of lead ions. The decreasing the current density could be due to the formation of elemental sulfur layer resulting in inactivation of the mineral surface.
