Abstract: The growth characteristics of nanometer CaCO3, the controlling mechanism of temperature,Ca(OH)2 concentration,additive species and adding amount acting on nanometer CaCO3 morphology and particle size were investigated by means of SEM. The results show that the growth of nanometer CaCO3 particles obeys MLS crystal growth model. With the increasing of Ca(OH)2 concentration,the CaCO3 crystal growth periods were found to be extended,and the aggregation growth of the nanometer CaCO3 particles due to the viscosity increase of the carbonation susp en sion was observed. The rise in reaction temperature may increase the CaCO3 crystal growth rate causing larger grain radii,also the CaCO3 crystal can reveal a morphology with higher lattice networking density. The ions produced due to the electroionization of the additive species can occupy the CaCO3 lattice-sites,or be absorbed on CaCO3 crystal faces,therefore changing the CaCO3 crystal surface energy. Hence,when the additive amount is large enough to cover active sites on crystal faces, the increasing of additive concentration can not further inhabit crystal growth.
Growth characteristics and controlling mechanism of nanometer CaCO3
Abstract:
The growth characteristics of nanometer CaCO 3, the controlling mechanism of temperature, Ca (OH) 2 concentration, additive species and adding amount acting on nanometer CaCO 3 morphology and particle size were investigated by means of SEM. The results show that the growth of nanometer CaCO 3 particles obeys MLS crystal growth model. With the increasing of Ca (OH) 2 concentration, the CaCO 3 crystal growth periods were found to be extended, and the aggregation growth of the nanometer CaCO 3 particles due to the viscosity increase of the carbonation suspension was observed. The rise in reaction temperature may increase the CaCO 3 crystal growth rate causing larger grain radii, also the CaCO 3 crystal can reveal a morphology with higher lattice networking density. The ions produced due to the electroionization of the additive species can occupy the CaCO 3 lattice sites, or be absorbed on CaCO 3 crystal faces, therefore changing the CaCO 3 crystal surface energy. Hence, when the additive amount is large enough to cover active sites on crystal faces, the increasing of additive concentration can not further inhabit crystal growth.