Low temperature electrolysis of iron ore in an aqueous alkaline solution - Volteron™

Volteron™ is a groundbreaking low temperature iron ore electrolysis technology developed through a strategic collaboration between ArcelorMittal and John Cockerill. Volteron™ supports ArcelorMittal’s broader strategy to achieve net-zero emissions by integrating innovative clean technologies. It follows up from the work carried out under the EU-funded Horizon 2020 SIDERWIN project realised between 2017-2023 to develop a new electrochemical process by electrowinning for CO2-free steel production

TECHNICAL DESCRIPTION

The Volteron approach is based on electrolysis to produce iron plates which are then converted into liquid steel in electric arc furnaces. First, a beneficiation step of iron ores including grinding of particles and flotation process is carried out. The resulting ultra-fine ore is then mixed with caustic soda and water to produce an electrolyte rich in iron oxide. The electrolyte solution circulates in the electrolysers where an electrochemical decomposition of the iron oxide takes place, resulting in iron deposits on the cathode and the production of iron metal plates. Oxygen is also produced as a by-product. The metallic iron plates produced by Volteron™ can be melted in EAF and integrated in classical downstream steelmaking processes.


The low temperature iron electrowinning reaction takes place in an aqueous electrolyte solution (50% NaOH) at 110°C. This process transforms iron oxide (Fe2O3) into metallic iron plates through a highly efficient and modular electrolysis method. The iron oxide reduction occurs at the cathode during the electrical current flow. During the process, hydrogen and oxygen gases are also produced due to the hydrolysis of water in the electrolyte. The hydrogen evolution reaction takes place on the cathode whereas the oxygen evolution takes place at the anode.

The main advantages of this technology are:
• Near-zero direct CO₂ emissions;
• High energy efficiency: this process is more efficient than other green steel technologies (the target for energy consumption is about 3,7 MWh/ton of iron plate);
• No need for H₂ or CCS infrastructure;
• The process is modular, scalable and compatible with intermittent renewable energy;
• This technology is based on proven technologies already developed over many years in the copper and zinc industries (strong intellectual property and know-how).


DEGREE OF MATURITY
The low temperature iron electrolysis process has been developed by ArcelorMittal Global R&D since many years, the key steps in this development are summarised below:
• 2004–2010: Ulcowin project (carried out as part of ULCOS – research project before Siderwin) leading to the development of the technology to TRL 3-4
• 2017 -2022: SIDERWIN EU-funded project including the commissioning of a pilot scale plant at ArcelorMittal Maizieres-les-Metz in France, with TRL 5-6 achieved in 2023.
• 2023–2025: Collaboration with John Cockerill for engineering of an industrial plant (named Volteron™)
• 2025: Commissioning of a 1 m² Volteron pilot plant allowing the production of about 140 kg of metallic iron in a row of 4 plates, in a cell equipped of 2 cathodes / 3 anodes. This pilot plant is fully representative of industrial cathodes/anodes size and is running since April 2025. While the results are very promising, it is still in a critical phase where it must prove its scalability and reliability at full industrial scale. The pilot is expected to validate TRL 7 by the end of 2025.
• By the end of 2025, ArcelorMittal in collaboration with John Cockerill will have completed an engineering and full CAPEX study for the realisation of a first Volteron scale up plant, scalable in 40 kt/year units up to 800 kt/year plants. The actual deployment time of the first scale up plant will depend on the results of the ongoing pilot tests, other framework conditions and funding opportunities.

CROSS-MEDIA EFFECTS
There are no negative environmental impacts from to the implementation of Volteron™ electrowinning technology. This process is generating a by-product linked to the regeneration of caustic soda used to make electrolyte. However, it is expected that sodium silicate manufacturers may be able to reuse this by-product as a raw material.


BARRIERS TO IMPLEMENTATION
• Capital expenditure and financial risk: The projected CAPEX for demonstration plants is substantial. This financial burden is a major barrier, especially given the uncertainty around long-term electricity pricing and the need for alignment on cost assumptions across stakeholders. Right now, work is focusing to improve design and materials choice for reducing the CAPEX of the demonstration plant.
• Availability of affordable required electricity: As for any other decarbonisation technology based on electrification, Volteron™ requires the supply of important amount of power. Its modularity will allow phasing investments with power availability, but it will require much more power generation than what is available today.

Basic information about the technique

Participant Companies