Research On Carbon Nanotubes Reinforced Lead-based Composite Anode For Zinc Electrodeposition

Zinc electrowinning is one of the important processes in zinc hydrometallurgy.Anode play an important role in electrowinning power consumption.Pb-Ag anode is widely used in the hydrometallurgical of zinc.The Pb-Ag anode used in this system has some disadvantages,such as a high oxygen evolution potential,high energy consumption,soft texture and easy deformation.Therefore,It is crucial to decreases the oxygen evolution potential to reduce the power consumption.The electrochemical deposition of low-oxidation lead powder was investigated,The effects of p H value,current density and gelatin content on current efficiencies,particle sizes,oxidation degree and electrocatalytic performance were investigated,Based on the optimal conditions for deposition of lead powder,the CNTs/Pb composite anodes was made by powder metallurgy.The effects of carbon nanotubes pretreatment,concentration,additives and electrolyte system on the current efficiencies,particle sizes,oxidation degree and electrocatalytic performance of composite powders were investigated.The effects of sintering atmosphere and forming pressure on the electrocatalytic performance of CNTS/Pb composite anodes were also investigated.It was shown that the lead powder obtained by electrodeposition with lead acetate system is mainly composed of lead and lead oxide.The main shapes of lead powder are bar,coral and dendritic.With the increase of p H and current density,the current efficiency increases first and then decreases,while the particle size and oxidation degree decrease first and then increase,The increase of gelatin concentration could increase the particle size of lead powder,current efficiency and oxidation degree could decrease.Under the optimal conditions of p H=3±0.2,current density 23m A·cm^-2,gelatin concentration 1 g/L and ultrasonic power 90W,the prepared lead powder has a median diameter of 5.33?m,an oxidation degree of 6.28%and the potential was 1.494V.The optimum conditions for preparation of CNTs/Pb composite anodes were as explored.Preparation of powders with 1 g/L slurry carbon nanotubes and 200 mg/L SDBS additives in lead acetate system,and the powders was sintered in vacuum environment at 410 MPa form pressure to prepare Anode.The potential of CNTs/Pb composite anode was stable at 1.447 V in 500 A/m ² current density.Compared with the traditional lead silver anode,it was lower than 59.1 m V,Compared with the pure lead anode,it was lower than 173.2 m V.