Electrochemical Chlor-Iron Process for Iron Production from Iron Oxide and Seawater

Abstract

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 seawater, while co-producing NaOH and Cl2 with industrially relevant current densities reaching 300 mA cm-2 and current efficiencies >90 %. 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 (< $500 per metric tonne) and the co-produced NaOH can be used for CO2 mineralization from the air or ocean, creating a net negative-emission process.

Electrowinning for room-temperature ironmaking: Mapping the electrochemical aqueous iron interface

“…16,[30][31][32] While these projects were monumental in laying the groundwork for this field, the emphasis on alkaline conditions has left broader questions on the nature of the interface under acidic conditions. Recent experimental work has revisited acidic iron electrowinning, 33,34 as well as the use of pH gradients, 35 highlighting questions about the underlying electrochemistry. Thus, general fundamental insights of the electrochemical iron interface is needed to further advance the electrowinning process.…”