Preparation Of Hydrogen Diffusion Anode And Its Application In Zinc Electrowinning Process

At present,the zinc electrowinning anode materials are mostly lead based multicomponent alloys,the high oxygen evolution potential is one of the most important problems that need to be solved urgently.On the basis of analyzing the current research status of zinc electrowinning anodes at home and abroad,the preparation of hydrogen diffusion anode(Hydrogen diffusion anode,HDA)and its electrowinning process are studied in this paper.The traditional anode and HDA reaction were discussed,the cathodic reaction was Zn2++2e = Zn,and HDA reaction by H2O-2e =1/2O2?+2H+ to H2-2e =2H+,to avoid the generation of oxygen evolution potential,will greatly reduce the cell voltage.Pt/C,Pd/C and Pt Pd/C electrocatalysts were prepared by electroless plating and characterized by TEM,EPMA and electrochemical tests.In the three catalysts,the noble metal particles are well covered on the surface of the toner,Pt/C catalyst performance is best,the exchange current density j0= 0.094mA/cm2.A flat plate substrate,a gas feed grid,a gas diffusion layer,a gas reaction layer and a special membrane of hydrogen diffusion anode were prepared.A variety of hydrogen diffusion anode plate substrates were designed and fabricated,and HDA was assembled.The results show that carbon paper exists in the form of columnar fibers before treatment,which can allow H2 and H2O to pass through.By treatment,the columnar fiber refinement disappears,and the carbon fiber is used to form the carbon fiber.To prevent the passage of H2O,with hydrophobic.In this paper,the effects of different Zn2+ concentration,H2SO4 concentration,eletrodes distance,current density,temperature and time on the voltage,current efficiency and DC power consumption of zinc electrowinning trough were studied by hydrogen diffusion anode.The results show that the application of HDA in the process of zinc electrowinning cell voltage,DC power consumption was significantly lower than that of Pb-Ag alloy anode,the application of HDA in zinc electro winning process of current efficiency is slightly higher than that of Pb-Ag alloy anode.Compared with the traditional Pb-Ag alloy anode,the stability of HDA is slightly worse,and the performance becomes worse after 30 minutes.