Study on the properties of Pb-Co3O4-PbO2 composite inert anodes prepared by vacuum hot pressing technique

Pb-PbO2, Pb-Co3O4 and Pb-Co3O4-PbO2 composite inert anodes were prepared by vacuum hot pressing technique from the mixtures of lead powders, Co3O4 and PbO2 particles in a fixed mould. The influences of heating temperatures and particles doping on the properties of the composite inert anodes were researched. The surface microstructures, phase structures and electrochemical properties were measured by X-ray diffraction (XRD), scanning electronic microscopy (SEM), energy dispersive spectrometer (EDS), anodic polarization curves (AP), cyclic voltammetry curves (CV), Tafel polarization curves and electrochemical impedance spectroscopy (EIS). The results showed that the uniform distributions of Co3O4 and PbO2 as the second phase particles in the composite inert anodes have been obtained by the vacuum hot pressing technique. The lead powders were melted and formed a uniform and compact matrix, in which the morphologies and properties of Co3O4 and PbO2 particles were kept. The electrochemical property and corrosion resistance of the composite inert anodes in a zinc electrowinning simulation solution were improved with the rise of heating temperatures during the vacuum hot pressing, and those were also enhanced by the doping of Co3O4 and PbO2 particles. This method solved the problems of the lower dispersion uniformity of the composite inert anodes prepared by composite electrodeposition or traditional casting technique.