Crystal Research and Technology
Cryst. Res. Technol. 42, 432 (2007) - Abstract -

Determination of nucleation parameters and the solid liquid interfacial energy of the KCl-ethanol-water system

Waid Omar and Joachim Ulrich*

Tafila Technical University, Department of Chemical Engineering, Tafila, Jordan
*Martin-Luther-Universität Halle-Wittenberg, Zentrum für Ingenieurwissenschaften, Verfahrenstechnik/TVT, 06099 Halle, Germany

Keywords nucleation parameters, potassium chloride, ethanol-water, solvent, solid liquid interfacial energy, activity coefficient, critical size
PACS 81.10.Dn
DOI 10.1002/crat.200610843

The kinetic parameters of homogeneous nucleation of KCl in different ethanol-water solvent mixtures were determined at 25°C from the experimental measurements of the width of the metastable zone at different cooling rates. The ethanol mass ratio in the ethanol water solvent mixture was varied from 0-0.9 and the metastable zone width for each solvent mixture was measured under the cooling rates of 10, 20 and 30 K/h. The influence of ethanol ratio on the activity coefficient was calculated. It was found that increasing the ethanol ratio in the solvent mixture leads to an increase in the mean molal activity coefficient. The experimental results obtained showed that the increase in the ethanol ratio in the solvent widens the metastable zone for the crystallization of KCl. Also it has inferred from the calculations based on the classical nucleation theory that increasing of the ethanol ratio in the solvent mixture resulted in an increase of the nucleation rate order, increase of the critical size of nuclei and increase of the solid liquid interfacial energy. It has been found that the solid liquid interfacial energy can be good correlated with inversely proportionality to the solubility.





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