Electrochemical chlor-iron process for iron production from iron oxide and salt water

Summary

The iron and steel industry accounts for ∼8% of global greenhouse gas emissions. Electrochemical reduction of iron ore to metal for electric arc furnaces can enable sustainable steel production, but existing electrochemical processes require expensive capital or electrolytes. We report a low-temperature, electrochemical cell that consumes low-cost and abundant iron oxide and aqueous sodium chloride, while co-producing sodium hydroxide and chlorine. Industrially relevant current densities and Faradaic efficiencies for iron production were demonstrated, with 94% selectivity to iron metal at an applied current density of 200 mA cm⁻². Freestanding films of phase-pure iron were formed after 4 h of continuous, stable electrolysis. The process can lead to levelized costs of iron that are competitive with iron produced in fossil-fuel-powered blast furnaces, and the co-produced sodium hydroxide can be used for CO₂ capture from the air or ocean, creating a net-negative-emission process.