Aluminium electrolysis with Fe-Ni-Al 2O 3 inert anodes at 850 °C

Abstract

Fe-Ni-Al 2O 3cermet materials were prepared, and the electrolysis with these anodes were performed in cryolite-based electrolyte consisted of 44NaF-40AlF 3- 8NaCl-5CaF 2-3Al 2O 3(wt%) at 850 °C. The purity of produced aluminium is 97-98%, while the calculated anodic corrosion rate is 18.2 mm=a-24.0 mm=a. The EPMA analysis showed that there is an oxide scale consisting of Fe 2O 3 and FeAl 2O 4 on the anode working surface. The homeostasis of dissolution and formation of oxide scale makes the thickness of the oxide scale and the cell voltage stable within a certain range. The dissolution of oxide scale results in the presence of FeF 3 in the electrolyte. By analysis of the corrosion process, it shows that low temperature, high alumina concentration and low CR electrolysis is preferred for using Fe-Ni-Al 2O 3 inert anodes for aluminium electrolysis. Copyright © 2011 De Gruyter.