Evaluation of Accelerated Mineral Carbonation Efficiency Using Industrial By-products and Estimation of Its Domestic Carbon Dioxide Reduction Potential

Objectives : Cement Kiln Dust (CKD), a cement industrial by-product, was used in this study to improve the effectiveness of CO2 removal and increase the production of precipitate calcium carbonate (PCC) in the accelerated mineral carbonation process, differentiating injection flow rate of alkaline agent into the process. Further, CKD, slag, waste cement powder (WC), coal fly ash (CFA) which are mainly used for mineral carbonation, were also compared for their total CO2 removal capability by the year.Methods : The morphology and composition of CKD were analyzed using FE-SEM, EDS and XRD to evaluate its applicability to mineral carbonation, and CKD extract and 1N NaOH were added into the reactor with the flow rate range of 1.1 to 3.0 mL/min for longer reaction time. And DTA was carried out for purity analysis of PCC. Last, for annual CO2 removal potential evaluation, CKD, slag, WC and CFA was compared based on the result from this and previous researches.Results : Result showed that 1N NaOH injection at flow rate of 1.1, 2.0, 3.0 mL/min accelerated the CO2 removal by the 61.7, 77.2, 41.5% and 48.2, 52.2, 54.3 g of PCC was generated respectively. The annual amount of industrial by-product in Korea is 26,664,893 tons/year, 8,000,000 tons/year, 2,531,750 ~ 7,595,250 tons/year and 884,854 tons/year, respectively, in order of Slag, CFA, CKD, waste concrete fine powder (WC). Thus, the annual removal of CO2 could be estimated in order of CKD > Slag > CFA > WC.Conclusion CKD is a fine powder form with a high specific surface area, high calcium content, and high alkalinity. Therefore, CKD is superior to waste concrete or slag in mineral carbonation in removing CO2 and generating PCC. Considering the annual amount of CO2 removal when applying industrial by-products to the CCUS process, CKD and slag are considered the most economical mineral carbonation materials.