A development that could decarbonize both the steel and cement industries: Swedish steel corporation SSAB has entered into a strategic cooperation with Heidelberg Materials to develop low-CO₂ cement solutions from steel slag. The partnership brings together two industries that together account for approximately 15 percent of global greenhouse gas emissions and could establish a new utilization pathway for industrial by-products.
Steel slag is generated as a mineral by-product during raw steel production and already exhibits properties relevant for cementitious applications due to its calcium oxide and silicon oxide content. To date, slag has been used primarily in road construction or as aggregate, but rarely as a direct clinker substitute in cement production according to DIN EN 197-1. The cooperation aims to systematically integrate slag from SSAB's fossil-free steel production – which is based on hydrogen direct reduction – as a recycling building material in cement formulations.
For Heidelberg Materials, slag integration could offer a dual advantage: On the one hand, the clinker content could be reduced, the production of which at temperatures above 1,450 degrees Celsius is extremely energy-intensive and accounts for approximately 60 percent of CO₂ emissions in cement production. On the other hand, the use of industrial by-products enables an improved EPD balance, which is increasingly relevant for public construction procurement. Today, blast furnace slag from conventional blast furnace routes is already being used as latent-hydraulic additives according to DIN EN 15167-1 – slag from hydrogen-based steel production could expand this approach.
For SSAB, the partnership opens an additional sales channel for a by-product that previously could only be monetized to a limited extent. The utilization of steel slag in the cement industry could improve the economic viability of the cost-intensive transition to green steel – an aspect that is critical for the competitiveness of fossil-free steel production. Both companies are pursuing ambitious climate goals: SSAB aims for completely fossil-free steel production by 2045, Heidelberg Materials wants to become climate-neutral by 2050.
The cooperation takes place in the context of a growing number of cross-industry partnerships in the building materials industry. Similar to the planned circular economy between SSAB and Heidelberg Materials, it is evident that decarbonization is no longer being approached in isolation within individual sectors, but rather systemically across value chains. Planners should monitor this development as alternative cement formulations are increasingly being anchored in technical standards and becoming relevant for project-specific sustainability certifications.
