Waste carbon from steel production can be recycled into new products

Gases from steel processing can be used to make materials for products like insulation boards and wood coatings, concludes an EU-funded project.

The project team demonstrated that carbon monoxide (CO) and carbon dioxide (CO₂) in blast furnace gas – a ‘process gas’ from steel production – can be recovered and used as the raw material for chemicals called polyols.

This project has made important contributions to the science and applications of CO and CO2 recycling. Dr Arturo Castillo Castillo

Polyols are used in polyurethane-based insulation materials and coatings and are typically derived from crude oil. Obtaining them from process gases therefore reduces the amount of crude oil that needs to be extracted and used, as well as reducing carbon emissions released to the atmosphere.

The Carbon4PUR project, which ran for 3.5 years, was funded by the EU’s Horizon2020 programme and led by materials manufacturer Covestro with 14 industrial and academic partners from seven countries, including Imperial College London. It concluded that the new technology was beneficial both environmentally and economically.

Important contributions

The project team identified new catalysts for the production of polyols from CO and CO₂ and gas mixtures. The technology was further scaled up to a semi-industrial scale. The insulation board manufacturer Recticel (Belgium) and the coatings manufacturer Megara Resins (Greece) have already used the technology to advance their own product development based on the research results.

Project partner Dr Arturo Castillo Castillo, from the Centre for Environmental Policy at Imperial, said: “This project has made important contributions to the science and applications of CO and CO₂ recycling. The team has identified effective ways to isolate the components for polyol production from process gases and has refined the process to move it beyond proof of concept.

“This has meant industrial partners have actually used the polyols in their product tests and shown that they perform well. It is exciting to see how emissions can be turned into products, giving one more life to the carbon that had already been used once.”

Mutually beneficial collaborations

Dr Castillo Castillo collaborated with the German Chemical Industry Association (DECHEMA) to investigate what the constraints and opportunities were for building mutually beneficial collaborations between the steel, chemical and potentially other industries across Europe.

This culminated in a publicly accessible tool where investors, industrial companies and project developers can identify locations where suitable emission sources are found in the right quantity and quality to potentially produce useful chemicals from waste gases.

Such a collaboration was evaluated by the Carbon4PUR project at the port of Marseille-Fos, France, where an ArcelorMittal steel mill is located in immediate proximity to a Covestro production plant.

Revolutionising production processes

Dr Markus Steilemann, CEO of Covestro, said: “The results of the research project have the potential to revolutionise production processes. This is a great discovery and a significant milestone on the road to a circular economy, where alternative raw materials become a reality."

Dr Castillo Castillo added: “It has been a great collaboration spanning seven countries and covering the whole value chain, from the steel mill providing the emissions to the polyol producer to the coatings and insulating foams manufacturers.”

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More about the outcomes on the project website: Carbon4PUR - Turning industrial waste gases (mixed CO/CO₂ streams) into intermediates for polyurethane plastics for rigid foams/building insulation and coatings