Extracting Aluminum from Aluminum Alloys in AlCl3-NaCl Molten Salts

Abstract

Extracting aluminum from aluminum alloys in AlCl3-NaCl molten salts was investigated in this paper. The influences of experimental parameters such as electrolyte composition, cathodic current density and electrolysis time on the deposits morphology were discussed. The results show that the grain size of the deposits decreases with the increase of AlCl3 content in the electrolyte. Current density has a big effect on the morphology of the deposits. The particle size of deposits increases with the increase of current density, and dendritic morphology forms at high current density. High nucleation rates are achieved at high current densities above the limiting diffusion current density, and will result in a finer grain size. A non-dendritic deposit of aluminum was obtained at 170°C at 50 mA cm−2 cathodic current density for 1 h in the electrolyte having a 1.3 molar ratio of AlCl3/NaCl. The purity of the aluminum deposit is about 99.79% analyzed using inductively coupled plasma.

Keywords

• aluminum extraction
• recycling
• aluminum alloy
• chlorides