Size dependency of citric acid monohydrate growth kinetics

An experimental study concerned with the growth kinetics of citric acid monohydrate crystals is presented. Due to the properties of the system, which is very soluble, with low solid-liquid density difference and high liquid viscosity, two different techniques were used: large crystals (710-850 mu m) were grown in a fluidized bed crystallizer; small crystals, belonging to three size ranges from 90 to 355 mu m, were grown in the cell of a laser light diffraction granulometer. A first order growth kinetics resulted in both cases; a comparative analysis of both the present data and those reported in the literature relevant to larger or smaller crystals, indicates that the system exhibits size-dependent growth, which increases linearly with the crystal size. (C) 1998 Elsevier Science S.A. All rights reserved.