Comparison of the activation of sphalerite by copper and lead

The adsorption of copper and lead and their subsequent xanthate uptake were compared at pH 3.0, 6.0 and 9.2 on both fresh and oxidized sphalerite. The extent of adsorption and the rate of adsorption were strongly dependent on pH, with the highest adsorption of CLI and Pb being at pH 9.2. In the presence of both Cri and Pb, Cu adsorption was enhanced and Pb adsorption was suppressed. The adsorption kinetics of Cu and Pb were characterized by two- and three-stage adsorption processes, respectively. The exchange ratio of Cu to Zi was about one and that of Pb to Zn was greater than one and varied with pH. The uptake of xanthate on "activated" sphalerite was dependent on pH. The maximum uptake was found robe at pH 6.0 for Cu-activated sphalerite and at pH 9.2 for PD-activated sphalerite. A measure of "activation strength" based on metal ion adsorption and xanthate uptake was introduced. The activation strength of Cu to Pb was about one at acidic pH, but it was higher at neutral (pH similar to 6) and alkaline (pH similar to 3) conditions. The oxidation of sphalerite decreased Pb and especially, Cu adsorption and decreased xanthate uptake.