Valorisation of steel slags for the cement industry

CO₂ emissions from the cement production process can be significantly reduced, if the clinker content is significantly lowered. However, traditional supplementary cementitious products (SCMs) such as granulated blast furnace slag and fly ash are becoming more difficult to source, due to the transition of the power plant and steel industry. Steel slags such as BOF and EAF slags are widely available, but they have no or little cementitious properties. However, the valorisation of such steel slags can be a game changer. In this market review, the existing and upcoming technical and market trends are outlined. The amount of converter slag produced in recent years has been decreasing, while the amount of electric furnace slag is increasing. It is expected that these trends will continue until 2035.