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

Kinetics of spontaneous precipitation of vaterite (CaCO3) from aqueous solu tion in the presence of ethanol, isopropanol and diethylene glycol was inve stigated by the constant composition method. The presence of the above-ment ioned additives resulted in acceleration of the crystal growth rate. Initia l rates of vaterite precipitation were proportional to the solution supersa turation and a surface energy of 43 mJ m(-2) was calculated according to th e 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 Else vier Science B.V. All rights reserved.