Investigation on Operating Conditions Influencing the Aluminum Electrolysis Using Chloroaluminate Ionic Liquids

AlCl3-EMIC (1-ethyl-3-methylimidazolium chloride) melt has attracted attention as an efficient electrolyte for Al electrolysis. However, several problems such as the low deposition rate and rough surface limit its practical use. In this study, we have investigated the influence of the electrolytic condition on the surface roughness of electrolytic Al foil by using the AlCl3-EMIC (molar ratio 2 : 1) melt with/without 20 mmol dm−3 of an OP (1,10-phenanthroline anhydrate) additive as an electrolyte. The AFM image revealed that the surface roughness (Sa) value of the electrolytic Al foil obtained on the Ti plate substrate from the melt with the OP additive at 50 ℃ was 45.8 nm at the current density of 52.6mA cm−2. A smooth electrolytic Al foil was found to be obtained even at high current density by increasing the operating temperature and adding OP to the melt.