Characteristics of alkali-activated fly Ash-CO2 mineralization reaction and micro carbon sequestration mechanism

Abstract

The mineralization reaction characteristics of alkali-activated fly ash with CO₂ directly influence its carbon sequestration capacity. Investigating the micro-scale carbon sequestration mechanisms in alkali-activated fly ash mineralization reactions is essential for improving the efficiency of mineralization and sequestration of fly ash. This study focuses on lignite fly ash from a coal-fired power plant in Shijiazhuang, China. A closed mineralization reactor experimental platform and a pressure drop method were utilized to characterize carbonation performance. The experimental results indicate that the alkali activation treatment effectively enhances the mineralization and carbon sequestration performance of fly ash. Alkali-activated lignite fly ash post-mineralization reaction surfaces showed significant carbonate material presence. After mineralization reaction, the distribution of particle sizes of alkali-activated lignite fly ash increased. The C-O bonds in mineralized fly ash increase with the degree of alkali activation, indicating that alkali activation treatment enhance the carbon sequestration capability of lignite fly ash.