Spontaneous precipitation of calcium carbonate in the presence of ethanol, isopropanol and diethylene glycol

Kinetics of spontaneous precipitation of vaterite (CaCO3) from aqueous solution in the presence of ethanol, isopropanol and diethylene glycol was investigated by the constant composition method. The presence of the above-mentioned additives resulted in acceleration of the crystal growth rate. Initial rates of vaterite precipitation were proportional to the solution supersaturation and a surface energy of 43 mJ m(-2) was calculated according to the classical nucleation theory. These additives influence the morphology of the vaterite crystals formed and stabilize this mineral phase by preventing the transformation to calcite. The apparent order found from kinetics data was eta > 2, thus suggesting a surface nucleation mechanism. (C) 2000 Elsevier Science B.V. All rights reserved.