Direct Leaching of Lead from Galena Using Acetic Acid in Iron(III) Chloride

Abstract

Investigations on the kinetics of leaching lead from galena (PbS), using acetic acid (HAc) solutions in iron(III) chloride (FeCl3) solutions, were conducted using shrinking core models. The effects of operational parameters, such as temperature, acetic acid iron(III) chloride concentration, and galena particle size, on the leaching process were also studied. The results revealed that the rate of galena dissolution was controlled by surface chemical reaction under all the experimental conditions examined. The empirical reaction orders of the leaching kinetics, with respect to iron(III) chloride and acetic acid concentrations, were 0.562 and 0.274, respectively, with an apparent activation energy of 60.82 kJ mol−1 in the temperature range 313–353 K. The leaching of galena using acetic acid solutions oxidized with iron(III) chloride showed a good leaching rate of lead acetates and, hence, combined acetic acid/iron(III) chloride leaching would make a relatively eco-friendly lead recovery system.