Study On Dissolution Characteristics And Electrochemical Mechanism Of Fe₂O₃ In Molten Salt

Compared with industrial iron,pure iron has the advantages of high melting point,good electrical conductivity,good ductility and corrosion resistance.Pure iron can be used to make electromagnet cores and is also used in aerospace and atomic research.In this paper,pure iron is prepared by molten salt electrodeposition method using NaCl-CaCl₂-Fe₂O₃melts.Related theories have been studied.The primary crystallization temperature of NaCl-CaCl₂-Fe₂O₃melts was determined by differential thermal analysis.It was found that the primary crystallization temperature increased with increasing Fe₂O₃content,and the lowest primary crystallization temperature was 507.25? when the content of Fe₂O₃was 2%.The dissolution of Fe₂O₃in the NaCl-CaCl₂-Fe₂O₃melts was determined to be physical dissolution by thermodynamic calculation and X-ray diffraction analysis.And calculation of the oxygen partial pressure and the theoretical decomposition voltage shows that it is feasible to prepare metallic iron in the NaCl-CaCl₂-Fe₂O₃melts by melts electrolysis,and the reduction process is carried out step by step,and a total of three steps of reduction:Fe₂O₃?Fe₃O₄?Fe O?Fe.Electrochemical reduction behavior of Fe₂O₃at different active cathodes(Pt/Fe/Ni/Mo)was investigated by cyclic voltammetry,square wave voltammetry,linear sweep voltammetry and open-circuit chronopotentiometry.The results show that Fe³⁺is a three-step reduction behavior in the NaCl-CaCl₂-Fe₂O₃melts,and the reduction process is Fe₂O₃?Fe₃O₄?Fe O?Fe.And Fe³⁺has different reversibility of reduction on different cathodes.In the melts of NaCl-CaCl₂(1:1)-Fe₂O₃(10g)and the high-purity nickel sheet and the graphite sheet was used as the cathode and the anode,respectively.The effects of current density,deposition time and so on on the surface morphology of electrodeposited iron were observed.At a current density of 1.0 A/cm²and a deposition time of 8 h,a deposited layer with good surface quality was obtained.Figure 57;Table 33;Reference 80.