亜鉛電解採取用Pb-Ag-Ca合金の機械的性質と電解挙動

The mechanical properties and electrolytic behavior of Pb-Ag-Ca alloy in the sulfuric acid electrolyte for insoluble electrode of zinc electrowinning were studied. Furthermore, experimental research on the influence of rolling and annealing treatments on these properties of Pb-Ag-Ca alloy was carried out. The results are summarized as follows.The tensile strength and yield strength of both as-cast and annealed Pb-0.5%Ag-(0.05 ∼ 1.0 %) Ca-alloys were the same or higher in comparison with the conventional Pb-1%Ag alloy. The tensile strength and yield strength of rolled Pb-0.5%Ag-0.6%Ca alloys shows a constant value after annealing at 200 °C for 48 hours. The Vickers hardness of Pb-0.5%Ag-Ca alloys shows a constant value after annealing at 200 °C for 48 hours. The Pb-0.5%Ag-Ca alloy shows the same or better mechanical properties relative to the conventional Pb-1%Ag alloy.The bath voltage of the Pb-0.5%Ag-0.6%Ca anode for the 20-day electrolysis experiments in the sulfuric acid solution decreased compared with the Pb-1%Ag anode, and the difference between the bath voltage corresponding to the Pb-1%Ag anode and the Pb-0.5%Ag-0.6%Ca anodes increased with increasing annealing time. The β-PbO2 diffraction peaks were detected by the X-ray diffraction patterns of Pb-0.5%Ag-0.6%Ca anodes after 20-day electrolysis and these peaks become sharper with increasing annealing time. It was considered that the β-PbO2 was one of factors contributing to the decrease of the bath voltage.