A Critical Review of the Ferric Chloride Leaching of Galena

Abstract

Abstract Ferric chloride leaching is a potentially attractive method of processing lead concentrates, and many studies have been carried out on the kinetics of dissolution of galena (PbS). In this paper, the extensive literature on galena dissolution is critically reviewed and the various results are compared on a consistent basis. There is a consensus that the leaching reaction is rapid and that elemental sulphur is the dominant reaction product. Although quantitative agreement among the various studies is lacking because of differences in galena purity, experimental procedures and methods, and data interpretation, the overall trends indicate a shallow temperature dependence, a direct total chloride concentration effect and a modest influence of solution agitation. Furthermore, there is an abrupt change in the reaction mechanism at FeCl3 concentrations less than ∼0.1 M. The experimental observations are consistent with rate control either by the outward diffusion of the PbCl2 reaction product through the...