In a significant stride towards sustainable industrial practices, researchers have discovered a method to enhance the carbon capture capabilities of steel slag, a byproduct of steel manufacturing. This innovation, published in the Journal of Engineering Science, not only promises to reduce carbon emissions but also offers a novel approach to waste management in the energy sector.
The study, led by Rong Sun of the School of Metallurgical Engineering at Anhui University of Technology, focuses on the direct carbonation of basic oxygen furnace (BOF) slag. This process involves reacting CO2 with steel slag to form stable carbonates, effectively sequestering carbon dioxide. However, the dense structure of steel slag and the inert forms of calcium oxide (CaO) within it have limited its carbonation performance.
To overcome these challenges, Sun and his team employed ball milling modification with the addition of potassium chloride (KCl). “Ball milling with KCl led to calcium enrichment on the surface of the BOF slag particles, reducing the diffusion resistance of CO2,” Sun explained. This process also facilitated the dispersion of slag particles, creating more micropores and mesopores that promote CO2 diffusion.
The experimental results were promising. With an optimal amount of KCl, the CO2 uptake and carbonation conversion of BOF slag reached a maximum of 46.3 g·kg–1 and 12.5%, respectively. However, excessive KCl was found to hinder performance by collapsing or blocking the pore structure and covering active sites on the surface.
The study also delved into the theoretical aspects, using density functional theory to understand the microstructural effects of K on CO2 adsorption. The calculations showed that adsorbed K on the C2S (010) surface enhanced the stability of CO2 adsorption, indicating that K strengthened the CO2 capture capacity of C2S.
This research offers a dual benefit: it improves the carbon sequestration performance of BOF slag and eliminates the presence of free-CaO in the slag, enhancing its volumetric stability. “This approach not only improves the carbon sequestration performance of BOF slag but also eliminates the presence of f-CaO in the slag, offering new insights into the resource utilization of BOF slag with alkali metal waste,” Sun noted.
The implications for the energy sector are substantial. By enhancing the direct carbonation performance of steel slag, this method could contribute to significant reductions in industrial carbon emissions. Moreover, it provides a viable solution for the utilization of steel slag, a waste product that has long posed environmental challenges.
As the world grapples with the urgent need to reduce carbon emissions, innovations like this offer hope and a path forward. The research by Sun and his team represents a significant step towards a more sustainable future, where industrial waste is not just managed but transformed into a resource for environmental good.
This study, published in the Journal of Engineering Science, underscores the potential of interdisciplinary approaches in addressing global challenges. It highlights the importance of combining experimental analysis with theoretical calculations to gain deeper insights and drive innovation in the field of carbon capture and utilization.