Abstract:Mixed copper anodes have become the inevitable choice for industrial electrolytic refining, but the anode passivation issues caused by impurity elements severely impact industrial production and cathode copper quality. The mechanism by which arsenic effectively suppresses anodic passivation remains unclear. This study investigates the influence of arsenic on anodic passivation behavior and its inhibition mechanism by analyzing the anodic polarization curve, constant-current oxidation curve, and constant-potential oxidation curve during the electrolysis of cast arsenic-containing mixed copper anodes. The anodic surface is characterized using AFM, while the passivation film and anodic sludge undergo XRD, SEM, and XPS characterization. The results indicate that an increase in arsenic content within the anode leads to a significant rise in its passivation potential and active dissolution time. Dissolution at the anode surface becomes more uniform, and the inhibitory effect on anodic passivation becomes increasingly pronounced. The passivation film primarily consists of Cu?O, while the anode sludge mainly comprises As?O? and Cu?As. The H+ ions generated by arsenic dissolution lower the pH at the anode surface, inhibiting the formation of the Cu?O passivation film. Higher arsenic content in the anode results in a more porous anode sludge structure that is prone to detachment. The lower passivation threshold for arsenic is 0.02 wt.%; below this value, the anode exhibits increased passivation tendencies. Copper scrap anodes with higher arsenic content are less prone to passivation.