Supercritical Carbonation of Steelmaking Slag for the CO₂ Sequestration

Abstract

Mineral carbonation of industrial byproducts is a promising carbon capture and storage technique to abate global warming. Steelmaking slag is the main byproduct of the steelmaking industry, and it is a potential source of alkaline oxides which can be transformed into carbonates. The carbonation of the steelmaking slag has proven to be a great countermeasure to sequester significant amounts of CO₂ emitted from the steelmaking process at the point sources while offering the environmental benefits of waste reduction. In this study, a supercritical carbonation process is developed to sequester CO₂ using steelmaking slag. Compared with conventional aqueous carbonation, this process has several advantages including higher reactivity, less waste generation, and better economic feasibility. A response surface methodology is utilized to assess the effect of operating parameters on carbonation efficiency and to optimize the process. Under the optimum conditions, the maximum CO₂ uptake of 213 gCO₂/kg_Slag is achieved. We believe that the findings of this study would help enable efficient CO₂ mitigation utilizing an efficient and environmentally sustainable process and thereby contribute to carbon neutrality and waste reduction.