Production of iron and oxygen in molten K2CO3–Na2CO3 by electrochemically splitting Fe2O3 using a cost affordable inert anode

Iron oxide was electrochemically split into iron and oxygen gas in molten Na2CO3–K2CO3 at 750 °C using a solid iron oxide cathode and a Ni10Cu11Fe alloy inert anode. Fe2O3 was electrochemically reduced to Fe on the cathode, releasing oxygen anions into the electrolyte and which were oxidized on the anode to generate O2. The cathodic current efficiency was as high as 95% and the energy consumption for producing 1 kg iron was 2.87 kWh, only half of the current industrial energy consumption of blast-furnace steel production. Due to the cost-affordable inert anode and the high energy efficiency, the method demonstrated in this work shows promise as a practical “green” iron production process.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Fe and O2 were produced simultaneously by electro-splitting of Fe2O3 in molten K2CO3–Na2CO3. ► A nickel alloy (Ni10Cu11Fe) was demonstrated a satisfactory inert anode in the melt. ► The current efficiency for iron production was as high as 95%. ► The process could be applied to produce other metals (Ni, Co Mn) and stainless steel.