Electrochemistry behavior and corrosion resistance of Al-Mn alloy prepared by recovering 1070-Al and Al-Mn alloys in ZnSO4 solutions

Abstract

In this paper, the low-cost Al-based alloy cathodes were prepared from recycled 1070-Al cathode plates, which are modified by adding Mn elements, and rolled with heat-treatment. The metallographic structure and mechanical properties of the above Al-xMn cathode plates were examined. The Tafel (potentiodynamic polarization), and EIS (Electrochemical Impedance Spectroscopy) tests were performed in ZnSO4 solution (50 g/Zn2++150 g/L H2SO4) and ZnSO4 solution containing 1 g/L Cl- (NaCl) ions. The corrosion resistance of the prepared cathodes was evaluated by accelerated corrosion experiments. The results showed that when the addition of Mn was 0.9 wt%, the metallographic structure of the alloy is finer, and the hardness increased to the largest, reaching about 65% than that of 1070-Al. The surface characteristics of the alloy samples after corrosion were obtained by SEM (Scanning Electron Microscope) and XPS (X-ray Photoelectron Spectroscopy). The surface corrosion pit of Al-0.9%Mn alloy was shallower because of the denser surface oxide film. Meanwhile, the electrodeposition experiments of zinc in high Cl- ions ZnSO4 solution were conducted, and the economic indexes of the recast Al-xMn cathode plate prepared in this experiment were all better than those of new 1070-Al cathode. This study provides experience and data support for the low-cost recycling of waste electrode plates for hydrometallurgy, which is conducive to the realization of energy-saving and emission reduction.