Gas-liquid reactive crystallization for the synthesis of CaCO3 nanocrystals

Research highlights: → Calcium carbonate nanocrystals have been prepared using gas-liquid reactive crystallization methods. → Reaction conditions influence the particulate sizes and morphology. → Dispersion agents reduce the particulate dimensions considerably. - Abstract: Calcium carbonate polymorphs were synthesized via gas-liquid reactive crystallization using a bubble column and a high gravity rotating reactor. A CO2-Ca(OH)2-H2O reactive crystallization system was used for the present study. The effect of the presence of citrate ions, meta phosphate ions and polyacrylic acid as dispersion agents was followed by means of particle size analysis and gas absorption capacity evaluation. The effect of dispersion agent concentration was also taken into account. The crystals prepared were characterized by SEM, XRD and BET surface area analysis. The particle size range of different crystals was between 130 nm and 40 nm and the morphology resembled mainly that of calcite variety.