Composition and morphology of the film formed on a lead alloy under conditions typical of the electro-winning of copper

Influence of lead dioxide surface films on anodic oxidation of a lead alloy under conditions typical of copper electrowinning

“…3. This is consistent with the surface film model, which indicates that the a-PbO 2 layer is the key to the oxidation rate of the lead alloy [13].…”

“…Our previous work [13] indicated that a continuous a-PbO 2 layer was the key factor in determining the oxidation rate. The presence of cobalt ions improves the imperviousness of the a-PbO 2 in hindering the oxidation of metallic lead to a-PbO 2 and also in hindering the oxidation of PbSO 4 to b-PbO 2 .…”

“…This paper extends previous [13,15] to address the following issues: (i) the manner in which the steady state surface film changes with oxidation time, (ii) the influence of cobalt ions on the formation of the initial lead sulphate film, (iii) film formation at constant potential and (iv) the potential of the oxygen evolution reaction on lead dioxide in relation to the oxygen evolution potential on lead anodes. The aim is to more fully understand the mechanism by which cobalt ions decrease the oxidation of the lead alloy under steady state conditions typical of copper electrowinning.…”

“…Subsequently, the composition and morphology of the anodic film formed on the lead anode alloy under conditions representative of copper electrowinning was characterized [13] by scanning electron microscopy, X-Ray diffraction (XRD) and X-Ray photoelectron spectroscopy (XPS). No cobalt compounds were detected by XRD and no cobalt peaks were detected by XPS.…”

Electrochemical impedance spectroscopy evaluation of behaviour of Pb–Ag anodes for zinc electrowinning

“…For Pb-0?56%Ag anode, the potential decay during the period from 10 to 60 min and then up to 6 h belongs to the third level; the electrochemical reactions are as follows 10 …”