Reduction mechanism and carbon content investigation for electrolytic production of iron from solid Fe₂O₃ in molten K₂CO₃–Na₂CO₃ using an inert anode
2013
Tang, Diyong | Yin, Huayi | Xiao, Wei | Zhu, Hua | Mao, Xuhui | Wang, Dihua
Iron and oxygen was recently electrochemically prepared in molten Na₂CO₃–K₂CO₃ eutectic melt at 750°C using a solid iron oxide pellet cathode and a cheap Ni10Cu11Fe alloy inert anode. This paper focuses to reveal the detailed reduction kinetics of solid Fe₂O₃ in the melt and also the effect of reduction potential on the carbon content in the iron product. The reduction mechanism was systematically investigated by cyclic voltammetric measurements, potentiostatic electrolysis combining with the composition and morphology analysis of the products obtained at different potentials. It was found that the reduction of Fe₂O₃ involves three steps, with the formation of intermediate products, viz., NaFe₂O₃ and NaFeO₂. The influence of electrolysis voltage/potential on the carbon content in the products was investigated by using both constant voltage and potentiostatic electrolysis under different conditions. The carbon content was found to be in the range of 0.035–0.76wt.%, depending on the applied cathodic potential. The iron-based products with higher carbon content can be obtained upon electrolysis at a higher cell voltage or a more negative potential. The present results also demonstrated a controllable extraction of Fe–C steels with desired carbon content through an environmental friendly way.
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