Effect of electrolysis superheat degree on anticorrosion performance of 5Cu/(10NiO-NiFe₂O₄) cermet inert anode

Abstract

5Cu/(10NiO-NiFe₂O₄) cermet inert anodes were prepared by cold-pressing and sintering process, and the effect of superheat degree of melting K₃AlF₆-Na₃AlF₆-AlF₃ on their anticorrosion performance was studied under electrolysis conditions. The results show that, the fluctuation of cell becomes small with increasing of superheat degree, which is helpful to inhibit the formation of cathodic encrustation; the concentration of impurities from inert anode in bath goes up to certain degree, but it is far smaller than those in traditional high-temperature bath. Increasing the superheat degree of melting K₃AlF₆-Na₃AlF₆-AlF₃ has unconspicuous effect on the contents of impurities in cathodic aluminum. The total mass fractions of Fe, Ni and Cu in aluminum are 15.38% and 15.09% respectively under superheat degree of 95 and 195 °C. From micro-topography of anode used view, increasing the superheat degree can aggravate corrosion of metal Cu in inert anode, and has negative influence on electrical conductivity of electrode to some extent.

Keywords

cermets / inert anode / aluminum electrolysis / electrolysis corrosion / superheat degree

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