Direct Electrodeposition of Iron from Iron Ore in Molten CaCl2-CaO

Developing electrochemical ironmaking technology is crucial for achieving global carbon neutrality. Herein, we report an electrochemical strategy to directly produce iron from iron ore in molten CaCl2-CaO. The dissolution-electrodeposition mechanism of iron ore in molten CaCl2-CaO system was investigated comprehensively. The results reveal that the addition of CaO significantly enhances the dissolution of iron oxide from the ore in molten CaCl2, increasing it from 0.012 wt.% to 0.55 wt.%. The dissolved iron oxide exists as ferrate ions (such as Fe2O42⁻ and Fe2O54⁻) in the melt. The influence of different electrolysis methods was also studied, revealing that constant voltage electrolysis produced iron products with a more pronounced dendritic morphology compared to constant current electrolysis. Furthermore, the purity of iron produced at a current density of 20 mA cm⁻2 is 99.519 wt.%, with a high current efficiency of 92.07%. A subsequent smelting process can further elevate the purity of the iron to an impressive level of 99.9955 wt.% (nearly 4N6). These findings suggest that direct electrodeposition of iron from iron ore in molten salt is a highly promising strategy.