Research progress in the preparation of iron by electrochemical reduction route without CO2 emissions

For decades, the steel production industry has been one of the largest sources of CO 2 emissions, accounting for 7% of global CO 2 emissions, of which 70% is emitted in the iron-making process. Currently, the main low-carbon iron production route is hydrogen metallurgy, which uses renewable energy to generate electricity, electrolyze water to produce hydrogen, and reduce iron with hydrogen. Thus, hydrogen metallurgy is also electrometallurgy. In this context, using the green electric energy one-step electrowinning of iron (ERI) will achieve technical route superiority. Developments in new energy generation technologies have led to renewed interest in ERI because of its green and low-carbon properties. In this study, progress in research into ERI was reviewed, and ERI categories, including molten salts, alkaline aqueous solutions, acidic aqueous solutions, and ionic liquids systems, were discussed. On this basis, ERI methods for various systems, including molten oxide electrolysis (MOE), Cambridge process (FFC), electrowinning, and ionic liquids-based methods, were introduced. Finally, the main challenges and possible solutions were summarized, and the development prospects and opportunities were prospected. The present research work will be beneficial to the development of this field. Graphical abstract