Effect of F− on the Corrosion Resistance of CF/Ti/β-PbO2 Anode for Zinc Electrowinning
摘要
Existing research on the erosion mechanism of F− and Cl− is mostly limited to the traditional lead-based anode system and the analysis of single concentration variables. Although a CF/Ti/β-PbO2 composite anode developed by our team in the early stage has shown outstanding performance advantages in the field of zinc electrowinning, its passivation-corrosion competition mechanism in fluorine/chlorine electrolytes has not yet been clarified, especially the concentration and current density of F− and Cl−. There is still a lack of systematic analysis of the evolution of the microstructure of the electrode interface and the structure-activity relationship of the macroscopic properties under the coupling of multiple parameters such as acid-zinc ratio. The effects of F− concentration, current density, and acid-to-zinc ratio on the energy consumption, corrosion resistance, and surface morphology of CF/Ti/β-PbO2 anodes for zinc electrowinning were investigated in this study. The results demonstrated that as F− concentration increased from 0 mg/L to 1000 mg/L, the cell voltage rose from 2.9 V to 4.87 V, and the self-corrosion potential decreased from 1.1758 V to 0.7581 V. With the increase in F− concentration, the energy consumption during zinc electrowinning rises, while both the electrochemical catalytic activity and corrosion resistance of the anode deteriorate. At a current density of 500 A/m2, the CF/Ti/β-PbO2 anode achieved optimal corrosion resistance, with a self-corrosion potential of 1.0967 V and a corrosion current density of 7.2098 × 10–5 A/m2. When the acid-to-zinc ratio was 3:1, the energy consumption during zinc electrowinning was minimized (cell voltage: 3.02 V), and the anode exhibited its best corrosion resistance (self-corrosion potential: 1.0967 V; corrosion current density: 7.2098 × 10–5 A/m2).