Mechanism analysis of carbide slag capture of CO2 via a gas-liquid-solid three-phase fluidization system

Abstract In the previous work, the industrial residue-carbide slag was used to capture CO2 via Ca-looping technology with high-temperature (above 823 K). Few studies are dealing with the capture of CO2 capture at low or even ambient temperature with carbide slag. In this work, based on an environment-friendly and cost-effective approach, carbide slag has been utilized to capture CO2 at low or even ambient temperature. It was confirmed that Ca can be transformed into CaCO3 completely via a three-phase fluidization system, at ambient temperature and pressure through theoretical and experimental investigations. In this process, an absorption value of 18.13 wt% can be achieved, which is higher than the values obtained in the case of some other Ca-based absorbents. After analysis the reaction mechanism, it was found that the model of carbide slag capture of CO2 via gas-liquid-solid three-phase fluidization system can be expressed based on the two-film theory and Fick’s law at the gas-liquid and liquid-solid interface. This study provides an investigation of a clean and energy-saving method to capture CO2, and an excellent pathway to reuse the industrial waste-carbide slag.