Accelerated Carbonation of Steel Slag and Their Valorisation in Cement Products: A Review

Abstract

Mineral carbonation emerges as a promising technology to tackle a contemporary challenge: climate change. This method entails the interaction of carbon dioxide with metal-oxide-bearing materials to produce solid carbonates resembling common substances (chalk, antacids, or baking soda). Given that steelmaking industries contribute to 8% of the global total emissions annually, the repurposing of their by-products holds the potential to mitigate CO2 production. Steel slag is a by-product of the metallurgical industry which is suitable for capturing CO2 due to its chemical composition, containing high CaO (24%–65%) and MgO (3%–20%) amounts, which increases the reactivity with the CO2. Moreover, the carbonation process can improve the hydraulic and mechanical properties of steel slag, making this by-product interesting to be reused in building materials. Different studies have developed in the last years addressing the possibilities of reducing the environmental impact of steel products, by CO2 sequestration. This study is dedicated to reviewing the basics of mineral carbonation applied to steel slag, along with recent advancements in research. Special emphasis is placed on identifying parameters that facilitate the reactions and exploring potential applications for the resulting products. The advantages and disadvantages of steel slag carbonation for the industrialization of the process are also discussed.