Optimized electrolytic reduction of iron oxide and hematite ore in molten lithium carbonate

Achieving the production of iron without associated carbon emissions is a critical goal for iron and steel industries in the global pursuit of net-zero. Among emerging technologies, electrolytic reduction of iron ore has received the least attention despite its promise as a direct and efficient approach. This technology uses electrolysis to separate oxygen from iron, renewable electricity providing a sustainable driving force compared to traditional carbon-based methods. In this study, high-purity iron was successfully produced via the electrolysis of iron (III) oxide dissolved in molten lithium carbonate at 750 °C. The process yielded metallic iron with >90 wt % purity, high crystallinity and particle sizes ranging from 300 to 600 μm. Experimental parameters including temperature, electrode materials, electrolyte composition, electrochemical control parameters, and post-treatment methodologies were systematically investigated to optimize the process and understand the reduction phenomenon. Results indicated that the solubility of iron (III) oxide in lithium carbonate evolves over time and can be influenced by certain additives. A Faradaic efficiency of >75 % was achieved using graphite as the cathode and SnO 2 as an effective inert anode, outperforming all other tested electrode materials. The electrolysis conditions optimized for iron oxide were successfully applied to Australian hematite-goethite iron ore, yielding no observed gangue contamination of the product and improved Faradaic efficiency of >90 %. This demonstrates the potential for using iron electrolysis for real medium-grade iron ores. • Consistent metallic iron formation achieved in molten carbon salt system. • Using a real iron ore feed did not contaminate the final iron product. • Experimental Faradaic efficiency toward iron formation of between 75 and 90 %. • Iron formation impacted by electrolyte composition, gas atmosphere and pre-treatment.