Electrochemical reduction of iron oxide in molten sodium hydroxide based on a Ni_0.94Si_0.04Al_0.02 metallic inert anode

Electrochemical tests, including anodic polarization, Tafel polarization and electrochemical impedance spectrum (EIS), were used to evaluate the anodic behaviors of a ternary alloy of Ni_0.94Si_0.04Al _0.02 in molten NaOH at 773 K. The results revealed that a conductive passivation layer had formed during electrolysis, which protected the N _i0.94Si_0.04Al_0.02 substrate from further attacked. An in situ test of anodic gases using a mass spectra indicated that oxygen was emitted from the interface of the Ni_0.94Si _0.04Al_0.02 anode. Meanwhile, the iron sponge can be electrochemically produced when Fe₂O₃ is used as cathode. The significant result is that the Ni_0.94Si_0.04Al _0.02 alloy is promising as an inert anode in molten NaOH electrolyte for a green metallurgical process.