Electrodeoxidation of Iron Oxide in Aqueous NaOH Electrolyte

Abstract

The production of iron and steel contributes to ~10 % of global CO2 emissions. Electrolysis is an alternative route to eliminate CO2 formation. Experiments were carried out in NaOH-H2O (50-50 wt%) electrolyte with a suspension of Fe2O3 particles at ~100 °C. A rotating disk electrode was used as the cathode. Different cathode substrates of different graphite qualities and silver were used. The current efficiency for iron deposition was consistently higher than 90 %. Silver was found to be an excellent substrate for good quality deposits. Cathodes in the form of pellets of hematite were also found to be reduced to iron by electrodeoxidation in the same electrolyte. Bauxite residue is a waste product from the Bayer process to produce aluminium oxide. The high content of iron oxide makes it a candidate for electrodeoxidation in a similar way.

The Materials Science behind Sustainable Metals and Alloys

“…One possibility for this is bauxite residues, which are an iron-rich waste product from alumina production. An interesting alternative to the high-temperature molten salt electrolysis is the recent progress in low-temperature electrolysis with ionic liquids as solvents. , Details of these methods with a focus on open research questions will be discussed in a separate section below.…”