Preparation of carbon dioxide‐adsorbing materials from fly ash‐modified steel slag and their performance optimization

Abstract Preparation of high‐efficiency carbon dioxide‐adsorbing materials from modified steel slag can simultaneously address the low comprehensive utilization rate of steel slag and reduce carbon dioxide (CO 2 ) emissions from iron and steel enterprises. In this study, CO 2 ‐adsorbing material was prepared by modifying steel slag with fly ash, and the effects of sintering temperature, heat preservation time, and the mass ratio of steel slag to fly ash on physical and chemical properties and CO 2 adsorption were examined. Results show that element migration occurred during sintering, especially of Ca and Fe. After modification, the components of C 2 S and CaO in steel slag reacted with the components of SiO 2 and Al 2 O 3 in fly ash to form Ca–Si–Al compounds, mainly including CaAl 2 Si 2 O 8 and Ca 2 Al 2 SiO 7 . The Ca–Si–Al compound was critical for the formation of pore structures in porous materials. After the modification, steel slag changed from its original tight, smooth structure to a rougher structure, forming many surface pores. The mass ratio imposed a significant effect on the pore structure. At a mass ratio of 1, a porous sphere with a uniform structure was formed, and the prepared CO 2 ‐adsorbing material showed favorable adsorption performance, with adsorption of CO 2 up to 0.219 g/g.