PREPARATION OF CaCO3PARTICLES IN WATER POOL IN NONAQUEOUS NONIONIC SURFACTANT SOLUTIONS

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Abstract
CaCO3 particles were prepared by bubbling of CO2 into the systems consisting of polyoxyethylene(6) nonylphenyl ether/aqueous Ca(OH) 2/cyclohexane. Spherical particles were formed in any systems, but those size distribution depended on the solubility behavior of aqueous Ca(OH) 2 in surfactant solutions, i.e., monodisperse particles were formed in colorless solution, whereas in blue translucent solution they became bimodal. Such change was also observed for the size of reversed micelles. This suggested that the formation of CaCO3 particles were related with that of micelles. On the other hand, the particles obtained were consisted of calcite, vaterite and aragonite. Those fraction differed also from the solubility behavior of aqueous Ca(OH) 2. Both the vaterite and aragonite were transformed into calcite and those rate constants were order of 10−6 sec−1.