Study on the Direct Electrochemical Reduction of Fe2O3 in NaCl-CaCl2 Melt

The electrochemical reduction kinetics of Fe 2 O 3 in melts were investigated by cyclic voltammetry, square wave voltammetry, open circuit potential and i-t curve analyses at 800°C utilizing a Fe 2 O 3 cathode filled in a metal pore molybdenum strip and a graphite rod anode. The composition and morphology of the product obtained by different cell voltage electrolysis were analyzed by XRD and SEM. The reduction mechanism of solid Fe 2 O 3 was a three-step electronic process, and two electrons were transferred each time to reduce it to metal iron (Fe 2 O 3 →Fe 3 O 4 →FeO→Fe). Among them, Fe 3 O 4 and FexO were produced in the process. In addition, an electrolysis voltage of 1.2~3.0 V was selected for constant potential electrolysis to determine the high current efficiency and low energy consumption. Finally, when an electrolysis voltage of 1.2V was applied, metallized iron with a particle size of 5 µm was obtained, and the current efficiency was 95.3%. The energy consumption was 3.35 kWh/kg. These studies provide a reasonable potential range process parameter for the green preparation of metallic iron by molten salt electrolysis.