Influence of Fe on film-forming mechanism of (Cu-Ni-Fe)-<i>x</i>NiFe₂O₄ composite inert anode for aluminum electrolysis in low temperature electrolyte

Abstract

Several (Cu-Ni-Fe)-xNiFe2O4(x=50,60,70,80,mass fraction/%) composite inert anodes with different contents of alloy phase were prepared using Cu, Ni, Fe and high-temperature synthetic NiFe2O4 by cold-pressing sintering method. The effect of Fe on the composition and microstructure of the (Cu-Ni-Fe)-xNiFe2O4 composite inert anodes during sintering and electrolysis process was studied. It is found that the redox reaction between Ni/Fe and NiFe2O4 phase occurs, leading to the dissociation and regeneration of NiFe2O4. In addition, the film-forming process and corrosion behavior of the (Cu-Ni-Fe)-xNiFe2O4 anodes were studied through low-temperature aluminium electrolysis test. The results indicate that the cell voltage is stable during electrolysis and the impurities in the produced aluminium are less than 0.7% (mass fraction), which indicates that (Cu-Ni-Fe)-xNiFe2O4 composite inert anode is one of the most promising inert anode materials, and the poor thermal stability of the ceramic anode is expected to be solved.

Keywords

• NiFe₂O₄
• composite material
• inert anode
• aluminum electrolysis