(371ao) Enhancing Circular Economy through Calcium Looping: Technoeconomic and Life Cycle Insights into Repurposed Steel Slag for CO2 Capture

Addressing climate change necessitates efficient CO₂ capture technologies. Existing methods, including solvent and adsorbent-based systems, face challenges like high energy demands and significant efficiency reductions in power plants^1,2. Calcium Looping (CaL) stands out for its potential in cost and efficiency improvements but is limited by the rapid degradation of CaO-based sorbents. This context prompts the exploration of steel slag, a by-product of steel manufacturing, as a promising, sustainable sorbent material for the CaL process. This study focuses on the utilization of ladle furnace slag (LFS) as an enhanced sorbent for CO₂ capture in the CaL process. It examines the techno-economic feasibility and life cycle impacts of employing slag-based materials, aiming to decarbonize the steel manufacturing industry.

Our study adopts a comprehensive approach, integrating advanced multiscale modeling with experimental techniques, to not only evaluate the performance of repurposed steel slag in the Calcium Looping (CaL) process but also to identify the optimal synthesis method for producing a viable green block from exhausted steel slag. This methodology encompasses tailoring the sorbent’s physical and chemical properties during synthesis, rigorously testing its CO₂ capture capabilities under varied conditions, and assessing its structural integrity and environmental impact. Special emphasis is placed on refining the synthesis process to enhance the sorbent's efficiency and durability, aiming to maximize its CO₂ sequestration potential while adhering to circular economy principles. Through this dual focus on performance evaluation and synthesis optimization, we seek to unlock the full potential of steel slag as a sustainable solution for CO₂ capture.

The modified ladle furnace slag (LFS) sorbent showcased a significant enhancement in CO₂ capture capacity, achieving a 47% increase over the baseline, with a CO₂ uptake of 0.48±0.01 gCO₂ per g of sorbent. This improvement underscores the effectiveness of our tailored synthesis process, making it a viable and efficient solution for sustainable CO₂ capture within the Calcium Looping (CaL) framework. The comparative analysis also revealed that the modified LFS outperformed traditional and commercially available CaO-based sorbents, demonstrating its potential for industrial application and contributing to the advancement of circular economy practices.

The study underscores the feasibility of repurposing steel slag as a functional sorbent for CO₂ capture, offering a pathway towards sustainable industrial practices. By leveraging waste materials for environmental benefits, it aligns with circular economy principles and contributes to the global efforts in climate change mitigation. Further research into sorption studies within actual CO₂ gas streams and comprehensive economic evaluations is necessary to realize the practical implementation of this technology.

In this presentation, we will unveil the promising results of transforming exhausted steel slag into an innovative green block for CO₂ capture. Our findings highlight the environmental benefits and structural integrity from a life cycle analysis, underscoring the potential of this approach

Refrences

1. MacDowell, N.; Florin, N.; Buchard, A.; Hallett, J.; Galindo, A.; Jackson, G.; Adjiman, C. S.; Williams, C. K.; Shah, N.; Fennell, P., An overview of CO2 capture technologies. Energy & Environmental Science 2010, 3(11), 1645-1669.
2. Balogun, Hammed A., Daniel Bahamon, Saeed AlMenhali, Lourdes F. Vega, and Ahmed Alhajaj. "Are we missing something when evaluating adsorbents for CO 2 capture at the system level?." Energy & Environmental Science 14, no. 12 (2021): 6360-6380.