(341f) Exploitation of Alkaline Solid Wastes for CO2 Mineralization and Utilization: Challenges, Advances and Opportunities

Proper stabilization of alkaline solid wastes, such as steel slag and fly ash, prior to their utilization is still challenging due to their high alkalinity, heavy metal leaching potentials and volume instability. In this presentation, we deploy an integrated approach to mineralizing flue gas CO₂ using alkaline solid wastes while utilizing the reacted product as supplementary cementitious materials to establish a waste-to-resource supply chain toward a circular economy. The challenges, advances and opportunities of CO₂ mineralization and utilization are illustrated. To ensure the viability of CO₂ mineralization and utilization using alkaline solid wastes, we also evaluate the reaction mechanisms at mineral-water interfaces for the control of reaction pathways and kinetics. Here we conduct high-energy synchrotron X-ray techniques to characterize the changes of mineral phases in petroleum coke fly ash during CO₂ mineralization and their subsequent utilization as supplementary cementitious materials in cement mortars. These findings could provide new information for understanding reactions of CO₂ mineralization and utilization at the mineral-water interface, which will help design the reaction processes at a large scale.