The effects of Nd on lead anode for zinc electrowinning

A detailed investigation of the effects of Nd on the microstructure, mechanical properties and electrochemical properties of lead anode in 160g.L-1 at 35 degrees C was carried out. Galvanostatic polarization and Chronopotentiometry (CP) were used to study the electrochemical behavior (such as anodic potential, corrosion rate and the composition of passive film) of the Pb and Pb-Nd anodes. The metallographic structure and passive film morphology of Pb and Pb-Nd anodes were observed and analyzed using polarizing microscope and scanning electronic microscopy (SEM), respectively. The experimental results show the grains become smaller and aggregation of PbxNdy become severe as the content of Nd increases. The addition of Nd enhances the formation of PbO2, inhibits the formation of PbSO4 and PbO and reduces the anodic potential. However, Holes presenting on rough passive film of high Nd content Pb-Nd anodes accelerate the corrosion.