Electrochemical behavior of aluminum and some of its alloys in chloroaluminate ionic liquids: Electrolytic extraction and electrorefining

摘要

The electrochemical behaviors of pure Al, Al-6%Si, Al-3%Cu, and Al-3.7%Cu-0.9%Mg-0.8%Pb-0.6%Fe alloys were investigated in the chloroaluminate ionic liquids 1-butyl-3-methylimidazolium chloride [BMIm]Cl/AlCl _3 (40/60 mol%) and 1-ethyl-3-methylimidazolium chloride [EMIm]Cl/AlCl _3 (40/60 mol%). Electrolytic extraction of copper from Al-Cu alloys in the employed ionic liquids was explored. The alloys were anodically dissolved in the ionic liquids and then pure copper was recovered under potentiostatic conditions. Due to the large difference between the deposition potentials of Cu and Al, pure Cu can be obtained without Al contamination. Electrorefining of Al-3%Cu and Al-6%Si alloys was also investigated in [BMIm]Cl/AlCl _3 (40/60 mol%) at room temperature. High purity aluminum deposits were obtained with significantly low energy consumption of about 2 kWh/kg of Al.