The corrosion behavior of a Ni0.91Cr0.04Cu0.05 anode for the electroreduction of Fe2O3 in molten NaOH

摘要

Stable inert anode is crucial to the electrochemical production of iron and oxygen from Fe2O3 as cathode in molten NaOH. A low-cost Ni0.91Cr0.04Cu0.05 inert anode is proposed and the corrosion behaviors are studied by polarization curves, Tafel plots, electrochemical impedance spectroscope (EIS). The results indicate that the Ni0.91Cr0.04Cu0.05 anode is more stable than Ni0.82Cr0.18 and graphite. A passivation layer consisting of (Ni0.8Cu0.2)O and little Cr2O3 is formed, preventing the Ni0.91Cr0.04Cu0.05 anode from corroding. The corrosion rate of Ni0.91Cr0.04Cu0.05 is 6.36 x 10(-5) g cm(-2) h(-1) after 24 h electrolysis. The remarkable result indicates the Ni0.91Cr0.04Cu0.05 alloy is a promising inert anode in NaOH melt for a green metallurgical extraction process. (C) 2018 Elsevier B.V. All rights reserved.