Preparation and Electrochemical Properties of an Al/TiB2-Ti4O7/PbO2 Composite Anode for Zinc Electrowinning
摘要
Anode material is critical for zinc electrowinning, and the selection and preparation of electrode materials are a focal point in hydrometallurgical research. In the present work, an Al/TiB2-Ti4O7/PbO2 composite anode was fabricated through a combination of plasma spraying and electrodeposition. The morphology and structure of the TiB2-Ti4O7 middle layer and PbO2 active layer were investigated by scanning electron microscopy and x-ray diffraction. Linear sweep voltammetry, Tafel polarization curves, and electrochemical impedance spectroscopy were used to analyze the catalytic activity and corrosion resistance of the composite anode. COMSOL Multiphysics software was used to simulate the electric field distribution of each element in the electrowinning cell. The results demonstrated that a dense and uniform layered structure, along with robust interfacial bonding, was essential for minimizing the interface resistivity and enhancing the corrosion resistance of the Al/TiB2-Ti4O7 matrix. The coating optimized at a current of 630 A exhibited superior conductivity and corrosion resistance, with excellent conductivity and current uniformity reducing the internal transmission resistance. In addition, it was observed that a low current density was not favorable for grain nucleation and deposition, whereas a high current density led to structural looseness and high inner stress. The electrochemical behavior of the Al/TiB2-Ti4O7/PbO2 composite anode was better than that of the Pb-Ag anode, offering lower cell voltage, higher current efficiency, and lower power consumption under identical zinc electrowinning conditions. The electric field analysis indicated that the composite anode provided a more uniform distribution of electric flux line and current density, more negative cathodic overpotential, and a higher zinc deposition rate than the Pb-Ag anode.
Graphical Abstract