Preparation Of Pb / Al Composite Anode And Its Properties In Electrolytic Zinc

In zinc electrolysis process, lead anode is adopted as the major anode material for its simple preparation, low cost, easy use and metal recycle. However, there still exist issues to be solved in low resistance, big density, low strength, easily soluble and high oxygen evolution potential, which lead to more consumption and contamination of electrolyte. So this study have tried to develop a new anode with good conductivity and high catalytic activity in order to reduce the cell voltage and energy loss.The research get the support of Mengzi mining and metallurgy company in order to produce a new anode, which is Al for inner core with low density and good electrical conductivity and coated by traditional Pb/Al composite material. Al was used to improve the electrical property without changing the reaction interface of electrolyte and the surface. In addition, interlayer was used to solve the problem of bonding in this paper, because Pb/Al is immiscible system. And X was added fot its high conductivity so that the property can be further improved.Pb/Al composite anodes were prepared by hot pressing diffusion method through orthogonal tests of interlayer component, preparation temperature, pressure and holding time. Resistivity, polarization curves, Tafel curves and AC impedance data were analyzed to optimize the best interlayer component and preparation process as well as discuss the effect of specific process conditions on the properties. In order to verify the actual effect of Pb/Al composite anode in the process of electrolytic zinc, anode with size of6mm×150mm×170mm can be produced on the basis of preliminary optimization of the preparation process. Compared with traditional lead anode, the comprehensive effect of different content of X interlayer and lead alloy surface on cell voltage, upper quantity, current efficiency, power consumption and the quality of cathode zinc would be analyzed. Finally, different electrolysis temperature, ratio of zinc and acid and performance of the two anodes were studied in this research. Moreover, the temperature and ratio of zinc and acid were optimized, compared its corrosion rate at the same electrolysis conditions and time to investigate the corrosion resistance of the composite anode.The study indicates that, the optimal technological conditions:interlayer contenting5.0%X, coated by traditional lead alloy, hot-pressing temperature is300℃, pressure is25MPa, holding time is1h. Compared with traditional lead anode, the composite anode has lower passive and anodic potential, furthermore, has larger radius of open circuit potential and impedance spectroscopy by means of polarization, Tafel and electrochemical impedance spectroscopy, which show that its has better corrosion resistance.The simulation results show that the anode of interlayer containing5.0%X has higher current efficiency and lower power consumption compared with traditional lead anode. When the current density is450A/m2, the power comsumption is5.69%lower. If the year producting is6,000,000tons,which can save400million yuan.Pb/Al composite anode show the exellent performance when the temperture is high than31℃and radio of zinc and acid is lower than2.83in optimization experiments.