Prospects and challenges of the electrochemical reduction of iron oxides in alkaline media for steel production

Abstract

Steelmaking industries have been facing strict decarbonization guidelines. With a net zero carbon emissions target, European policies are expected to be accomplished before 2050. Traditional steelmaking industry still operates by the carbothermic reduction of iron ores for steel production. Consequently, the steel sector is responsible for a large amount of CO2 emissions, accounting for up to 9% of the CO2 worldwide emissions. In this scope, the electrochemical reduction or electrolysis of iron oxides into metallic iron in alkaline media arises as a promising alternative technology for ironmaking. Significant advantages of this technology include the absence of CO2 emissions, non-polluting by-products such as hydrogen and oxygen gases, lower temperature against the conventional approach (∼100°C versus 2000°C) and lower electric energy consumption, where around 6 GJ per ton of iron manufactured can be spared. The present minireview discusses the progress on the electrochemical reduction of iron oxides in alkaline media as a green steelmaking route. A historical overview of the global steelmaking against recent developments and challenges of the novel technology is presented, and the fundamental mechanisms of iron oxide reduction to iron and alternative iron feedstocks are discussed. Factors affecting the Faradaic efficiencies of the alkaline electroreduction of iron oxide suspensions or iron oxide bulk ceramics are also explored, focusing on the concurrent hydrogen evolution reaction. Overall, if scrutinized, this technology may become a breaking point for the steel industry sector.

Deoxidation Electrolysis of Hematite in Alkaline Solution: Impact of Cell Configuration and Process Parameters on Reduction Efficiency

“…This is due to the substantial overlap in their constituent components. Prior investigations on suspension systems have demonstrated comparable behaviors and performance characteristics within similar ranges [21] …”

“…Prior investigations on suspension systems have demonstrated comparable behaviors and performance characteristics within similar ranges. [21]…”

“…Nevertheless, the reported inconsistent range of Faradaic efficiencies in previous studies (5–100 %) [21] lacked differentiation between anode types, experimental environments, and cell configurations. In contrast, we suspected that these process parameters likely influence the overall electrolysis performance.…”

“…[15] The feasibility of the method for lower grades of iron oxide feedstocks such as pseudobrookite (Fe 2 TiO 5 ), [17] titanomagnetite iron sand (Fe 2 + (Fe 3 + , Ti) 2 O 4 ), [18] and red mud (iron-rich waste from the aluminum industry) was also shown. [19,20] Nevertheless, the reported inconsistent range of Faradaic efficiencies in previous studies (5-100 %) [21] lacked differentiation between anode types, experimental environments, and cell configurations. In contrast, we suspected that these process parameters likely influence the overall electrolysis performance.…”

Vanadium-Doped Induction of Bare Active Crystalline Planes of Tungsten Oxide and Its Excellent Anticorrosion Properties

“…Corrosion is a worldwide issue that causes huge economic losses, energy wastage, and safety hazards . Epoxy resins are commonly used for metal protection because of their macromolecular nature, which provides better surface coverage and corrosion protection activity than simple organic corrosion inhibitors . Additionally, the corrosion protection effect of epoxy resin coatings can be further enhanced by adding organic and inorganic functional materials.…”