Preparation And Properties Of Al/TiB₂+Ti₄O₇ Composite Matrix Surface Electroplating PbO₂ Energy-Saving Electrode

Electrode is a key material for non-ferrous metal electrolysis,and its selection and preparation is one of the difficult problems in the hydrometallurgical industry.This article starts with the selection of electrode materials and structural design,combining the Al/TiB₂+Ti₄O₇ coating composite material prepared by plasma spraying technology in the early laboratory as the matrix.Through the measurement of porosity,it is found that the spraying power of the composite electrode material prepared by plasma spraying method is 36k W,the powder feeding rate is 30g/min,the spraying distance is105mm,and the argon flow rate is 2.6m³/h of conditions,which greatly reduces the charge resistance in the layered composite electrode structure,thereby accelerating the charge transfer rate.Plasma spraying has successfully prepared an intermediate composite coating with corrosion resistance.The electrochemically active coatings of?-PbO₂ and?-PbO₂+MnO₂,?-PbO₂+CeO₂were prepared by electrochemical deposition.The phase composition of the coating was analyzed with an X-ray diffractometer,and the structure of the coating was observed with a scanning electron microscope.SEM and EDX analysis results show that the Al/TiB₂+Ti₄O₇/?-PbO₂ electrode prepared by electrodeposition at a current density of 0.03A·cm^-2 has a more compact structure and a more uniform grain size.By adding Mn²⁺and Ce³⁺to the?-PbO₂ plating solution for the surface active layer,the microstructure of the electrode coating can be changed,the internal stress of the coating and the substrate can be reduced,and the electrocatalytic activity can be improved.The presence of MnO₂ in the electrolyte can make the grains of the PbO₂deposited layer more fine and uniform.The doping of MnO₂ makes the grain arrangement on the electrode surface more uniform and dense,so that the plating layer has higher stability during the electrolysis process.By co-depositing PbO₂ and different contents of MnO₂ on the surface of the composite electrode,the high conductivity of lead dioxide and the high electrocatalytic activity of MnO₂ can be successfully combined.CeO₂ is a widely used rare earth catalytic material.Ce³⁺can improve the corrosion resistance of the material and improve its electrocatalytic performance.It is considered to be a promising dopant to improve the electrocatalytic activity and stability of PbO₂ electrodes.Through open circuit potential test,steady state polarization curve,cyclic voltammetry(CV),linear sweep voltammetry(LSV)and electrochemical impedance spectroscopy(EIS),the electrochemical performance of the electrode was studied.Experiments show that the best effect is when the doping amount of Mn²⁺is 80g/L,the overall performance of the electrode is the best under this condition.The analysis peaks of oxygen evolution peak and reduction showed that Ce³⁺promoted the oxygen release reaction and reduced the potential of oxygen release and energy consumption.The PbO₂-CeO₂ electrode coating has good reversibility.In the experiment,the Ce³⁺doping with different content was studied,and it was found that the performance was the best when the doping amount was 1.5g/L.Plasma spraying and electrochemical deposition have successfully prepared Al/TiB₂+Ti₄O₇/?-PbO₂/?-PbO₂+MnO₂/?-PbO₂+CeO₂composite electrode materials with corrosion resistance and electrochemical catalytic activity.Compared with Al/TiB₂+Ti₄O₇/?-PbO₂ electrode,the corrosion resistance of Al/TiB₂+Ti₄O₇/?-PbO₂+MnO₂/?-PbO₂+CeO₂ is increased by 10.1%and 23.3%,respectively,and the corrosion resistance is significantly enhanced.At the same time,the electrode polarization potential is also negatively shifted by 559m V and 835m V,and the catalytic activity is also significantly improved.Finally,the zinc electrowinning simulation experiment was carried out on the prepared electrode material.Mainly research the lead-silver alloy anode Pb-(0.5wt.%)Ag/?-PbO₂ and Ti/?-PbO₂ used in traditional zinc electrowinning and Al/TiB₂+Ti₄O₇/?-PbO₂+CeO₂ prepared under plasma spraying process conditions.The electrode was used in the Zn SO₄-H₂SO₄ solution system((C(Zn²⁺):50-60g/L,C(H⁺):155-165g/L))to carry out the zinc electrowinning simulation experiment,and the above anode materials were tested in the zinc electrowinning Performance indicators such as cell voltage,cathode load,current efficiency and power consumption during the process.After comparison at a current density of 400 A·m^-2,the cell voltage of the new electrode material is 70m V lower than that of the lead-based electrode cell,and about 200 m V lower than the cell voltage of the titanium-based electrode;the quality of zinc precipitated by the new electrode material is higher than that of the lead-based electrode.0.53g higher,0.71g higher than the precipitation of titanium-based electrode metal;the current efficiency of the new electrode material is 3%higher than that of the lead-based electrode and 4%higher than the current efficiency of the titanium-based electrode;the new aluminum-based electrode Compared with the lead-based electrode,the electric energy consumption of the material is reduced by 168k W·h/t and the electric energy consumption of the titanium-based electrode is reduced by 326k W·h/t.The results show that the new electrode has been improved to a certain extent,achieving the effect of energy saving.