A development that could advance both the cement and steel industries in their decarbonization strategies: Swedish steel corporation SSAB and Heidelberg Materials have agreed on a cooperation to develop alternative cement solutions based on steel slag. The partnership aims to utilize industrial by-products from steel production as high-quality raw material for cement manufacturing, thereby significantly reducing the CO₂ intensity of both processes.
Steel slag is generated as a mineral by-product during pig iron production in blast furnaces as well as during steel refining. While it has previously been used mainly in road construction or as an aggregate in concrete production, its material integration into the cement matrix could represent a significantly higher-value utilization. Particularly in the production of CEM III cements, which already contain a high proportion of blast furnace slag, the clinker factor can be further reduced. Since clinker production is the most CO₂-intensive step in cement production, substitution with secondary raw materials offers considerable decarbonization potential.
Through the cooperation, SSAB gains an additional opportunity to economically utilize the by-products from green steel production. The company has been focusing for years on converting its steel production to hydrogen direct reduction, which leads to changed slag compositions. The partnership with Heidelberg Materials could thus not only establish a new business model in the circular economy, but also secure the acceptance and standards compliance of these new material flows. For planners and building owners, what will be decisive is the extent to which the resulting cements meet the requirements of DIN EN 197-1 and what effects on the mechanical properties and durability of concrete are to be expected.
The collaboration is part of a series of initiatives with which the cement industry aims to reduce its dependence on Portland cement clinker. Holcim and other manufacturers are also working on substituting primary raw materials with industrial by-products. Key to market success will be whether the new cement formulations are economically competitive, can demonstrate an EPD with significantly reduced CO₂ footprint, and simultaneously meet the required strength classes and exposure classes. The partnership between SSAB and Heidelberg Materials shows that industrial symbioses between steel and building materials industries are increasingly becoming a strategic component of decarbonization – with potentially far-reaching impacts on standardization, product availability, and pricing in both sectors.
