The electrochemical reduction process of ZnFe₂O₄ in NaCl-CaCl₂ melts was studied. Thermodynamic analysis shows that the reduction process of ZnFe₂O₄ is carried out in multiple steps, and it is difficult to reduce Fe³⁺ to Fe in one step. Electrochemical tests revealed that the reduction process of ZnFe₂O₄ includes three steps: First, Fe³⁺ is reduced to Fe in two steps, then Zn²⁺ is reduced to Zn in one step. The reduction of Fe³⁺ on the Mo electrode is a reversible process controlled by diffusion, while the reduction of Zn²⁺ is an irreversible process controlled by diffusion. The influence of electrolysis voltage and temperature on the process of electric deoxidation has also been studied. It is indicated that properly increasing the temperature is conducive to the diffusion of oxygen ions, thereby increasing the deoxidation rate. With the gradual increase of voltage, the reduction process of ZnFe₂O₄ is ZnFe₂O₄ → FeO + ZnO → Fe + ZnO → Fe + Zn.

The presence of calcium-containing molten salts in the electrolysis of oxides for metal production can lead to the formation of CaO and, subsequently, the generation of intermediate products, affecting the reduction of metals. To investigate the impact of CaO on the reduction process, experiments were conducted using a Fe₂O₃-CaO cathode and a graphite anode in a NaCl-CaCl₂ molten salt electrolyte at 800 °C. The electrochemical reduction kinetics of the intermediate product Ca₂Fe₂O₅ were studied using cyclic voltammetry and I-t curve analysis. The phase composition and morphology of the electrolysis products were analyzed using XRD, SEM-EDS, and XPS. The experimental results demonstrate that upon addition of CaO to the Fe₂O₃ cathode, Ca₂Fe₂O₅ is formed instantly in the molten salt upon the application of an electrical current. Research conducted at different voltages, combined with electrochemical analysis, indicates that the reduction steps of Ca₂Fe₂O₅ in the NaCl-CaCl₂ molten salt are as follows: Ca₂Fe₂O₅ ⟶ Fe₃O₄ ⟶ FeO ⟶ Fe. The presence of CaO accelerates the electrochemical reduction rate, promoting the formation of Fe. At 0.6 V and after 600 min of electrolysis, all of the Ca₂Fe₂O₅ is converted into Fe, coexisting with CaCO₃. With an increase in the electrolysis voltage, the electrolysis product Fe particles visibly grow larger, exhibiting pronounced agglomeration effects. Under the conditions of a 1 V voltage, a study was conducted to investigate the influence of time on the reduction process of Ca₂Fe₂O₅. Gradually, it resulted in the formation of CaFe₃O₅, CaFe₅O₇, FeO, and metallic Fe. With an increased driving force, one gram of Fe₂O₃-CaO mixed oxide can completely turn into metal Fe by electrolysis for 300 min.