Experimental study on CO2fixation by three types of fly-ash: Effect of average particle size and Ca2+ leaching on the CO2 fixation reaction rate

Toward a decarbonized society, the authors have studied the CO2 fixation of fly-ash containing Ca2+ and propose a plant for CO2 fixation that reacts CO2 gas with the fly-ash. In this study, the relationship between the reaction rate and two basic characteristics which are average particle size and the amount of calcium eluted was evaluated to propose an effective index for selecting samples which is suitable for the plant. Three types of fly-ash with different average particle size and Ca2+ elution were selected as samples, and the CO2 fixation reaction rate was calculated from the column test. As a result, the samples with the largest values for mean particle size and the amount of calcium eluted showed the largest reaction rates, and the samples with the smallest values of two characteristics showed the smallest reaction rates. These results suggest that the mean particle size and Ca2+ elution have a significant effect on determining the magnitude of CO2 fixation reaction rates.