Influence of additions of synthetic anhydrous calcium carbonate polymorphs on nanolime carbonation

0508048 - ÚTAM 2020 RIV GB eng J - Journal Article
Ševčík, Radek - Mácová, Petra - Pérez Estébanez, M. - Viani, Alberto
Influence of additions of synthetic anhydrous calcium carbonate polymorphs on nanolime carbonation.
Construction and Building Materials. Roč. 228, December (2019), č. článku UNSP 116802. ISSN 0950-0618. E-ISSN 1879-0526
R&D Projects: GA ČR(CZ) GA17-05030S
Institutional support: RVO:68378297
Keywords : nanolime * calcium carbonate CaCO3 * Ca(OH)2 * carbonation * polymorphs
OECD category: Materials engineering
Impact factor: 4.419, year: 2019
Method of publishing: Limited access
https://doi.org/10.1016/j.conbuildmat.2019.116802

The influence of synthetic anhydrous calcium carbonate polymorphs, calcite, vaterite and aragonite, on carbonation of nanolime suspension, has been investigated. The higher rates of carbonation observed after 7 days in mixtures containing vaterite and aragonite particles, found explanation in the control exerted by heterogeneous nucleation on the water-mediated reaction mechanism and in the enhanced carbon dioxide diffusivity in the sample volume, both facilitated by the higher specific surface of the powders and the microporous sample fabric. Introduction of synthetic calcium carbonate allowed for exerting control on formed polymorphs, subverting the order of their (meta-)stability. The peculiar microstructure obtained by adding aragonite rod-like particles, mitigates the propagation of desiccation cracks (which impair continuity of the carbonated nanolime film). The mechanism, although still not completely understood, likely involves the regulation of evaporation of liquid fraction and redistribution of the tensional stresses during drying and nanolime crystallization. The obtained results provide new insights into the crystallization of carbonates from nanolime particles and may help in the design of innovative compatible products for consolidation of lime-based materials and carbon dioxide sequestration.
Permanent Link: http://hdl.handle.net/11104/0299003