FerroSilva develops innovative way to produce fossil-free sponge iron

FerroSilva — a joint initiative between KTH Royal Institute of Technology, Chalmers University of Technology, Ovako, Sveaskog, and several other organisations — has developed an innovative manufacturing process for fossil-free sponge iron

Discussions over hydrogen-based methods have dominated the fossil-free sponge iron sector over the past years. FerroSilva, however, says that the hydrogen-based approach has difficulty progressing past the experimental stage due to the lack of technical maturity of electrolyses and issues in maintaining heat balance during the reduction process.

The initiative argues that the popular hydrogen-based approach consumes a significant amount of electricity. Ovako senior advisor Göran Nyström said the new process needed less than a tenth of the electricity per tonne of the finished product compared to its hydrogen-based counterpart. Nyström also said the new process mostly used energy from gasified forest residues.

Initiated in 2020, the FerroSilva project produces biomass gas from forest byproducts, such as chipped branches and tops. It dries the chips and gasifies them in a fluidized bed to produce a cleaned form called synthetic natural gas (syngas).

The syngas produced by FerroSilva has similar carbon monoxide and hydrogen compositions to reformed natural gas. It allows the project to conduct iron ore pellet reduction via a regular shaft furnace process.

FerroSilva’s feasibility study last autumn revealed that the new method would be cheaper than other initiatives to make green sponge iron in Europe. This method is suitable for commercial sponge iron manufacturing in countries with “good access” to biomass.

The project’s energy-efficient manufacturing process also generates several industrial inputs, including biochar and biogenic carbon dioxide. Biogenic carbon dioxide is a material for electro fuel production, which is expected to contribute significantly to the sustainable transport industry.

“In addition, there are letters of intent with OX2 and Linde for parts of our future production of liquid biogenic carbon dioxide,” Nyström said.

The project plans to construct its first factory at Ovako’s Hofors plant, aiming to start production in 2026 with a production capacity of 50,000 tonnes per year. FerroSilva has signed a letter of intent with Sveaskog for its input materials.