TY - GEN
T1 - Effects of carbonation on the mineral composition of cement kiln dust
AU - Anderson, Cecilia P.
AU - Sutter, Lawrence L.
AU - Huntzinger, Deborah N.
AU - Gierke, John S.
PY - 2007
Y1 - 2007
N2 - Due to their relatively high calcium oxide content, industrial mineral oxide wastes are potential candidates for mineral sequestration of carbon dioxide (CO2). Cement kiln dust (CKD) contains 20-60% CaO making it a possible candidate for CO2 sequestration. In this study, three types of CKD are characterized, before and after carbonation, using environmental scanning electron microscopy and energy dispersive x-ray microanalysis to determine the mineralogical and morphological changes occurring due to carbonation. The reactants, products, and precipitation mechanisms were investigated to enhance understanding of the governing processes and allow better utilization of CKD for CO2 sequestration. The results of multiple independent analyses confirmed the formation of CaCO3 during carbonation. Examinations of the reaction pathways found that CaO and calcium hydroxide (Ca(OH)2) were the major reactants. Three types of CaCO3 precipitation mechanisms were observed: (1) diffusion of CO2 into Ca(OH)2 particles causing precipitation in the pores of the particle and the growth of a CaCO3 skin from the outside inward, (2) precipitation onto existing particles, and (3) precipitation from aqueous solution. The CaCO3 skin may slow further diffusion of CO2 into a particle, thus slowing the overall sequestration rate.
AB - Due to their relatively high calcium oxide content, industrial mineral oxide wastes are potential candidates for mineral sequestration of carbon dioxide (CO2). Cement kiln dust (CKD) contains 20-60% CaO making it a possible candidate for CO2 sequestration. In this study, three types of CKD are characterized, before and after carbonation, using environmental scanning electron microscopy and energy dispersive x-ray microanalysis to determine the mineralogical and morphological changes occurring due to carbonation. The reactants, products, and precipitation mechanisms were investigated to enhance understanding of the governing processes and allow better utilization of CKD for CO2 sequestration. The results of multiple independent analyses confirmed the formation of CaCO3 during carbonation. Examinations of the reaction pathways found that CaO and calcium hydroxide (Ca(OH)2) were the major reactants. Three types of CaCO3 precipitation mechanisms were observed: (1) diffusion of CO2 into Ca(OH)2 particles causing precipitation in the pores of the particle and the growth of a CaCO3 skin from the outside inward, (2) precipitation onto existing particles, and (3) precipitation from aqueous solution. The CaCO3 skin may slow further diffusion of CO2 into a particle, thus slowing the overall sequestration rate.
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M3 - Conference contribution
AN - SCOPUS:84878825508
SN - 9781604232158
T3 - International Cement Microscopy Association - 29th International Conference on Cement Microscopy 2007
SP - 441
EP - 470
BT - International Cement Microscopy Association - 29th International Conference on Cement Microscopy 2007
T2 - 29th International Conference on Cement Microscopy 2007
Y2 - 20 May 2007 through 24 May 2007
ER -