Electrochemical Separation of Aluminum from Mixed Scrap Using Ionic Liquids

Electrodeposition of aluminum was conducted on three types of ionic liquids (ILs); EMIC, BMIC and HMIC with AlCl3. The molar ratio of IL:AlCl3 = 1:2 was determined to be optimum for all three ILs. Over 170 A/m2 current density with more than 85% current efficiency was obtained for EMIC system. Similarly, for BMIC, over 300 A/m2 current density was found with more than 85% current efficiency, and for HMIC, more than 250 A/m2 of current density with over 85% current efficiency was obtained. Based on the lab-scale experimental findings, scale-up experiments were carried out for BMIC:AlCl3 = 1:2 molar ratio. Significant increase in current density was observed when higher potentials were applied. More than 220 A/m2 of current density was observed for the scale-up system. Additionally, shorter distance between anode and cathode (~1 cm) and higher stirring rate (120 rpm) produced higher current densities. The outcome of this work would facilitate the scale-up studies for the electrochemical separation of aluminum from mixed scrap.