A simple model for the kinetic evaluation of zeolite crystallization processes

Abstract

Assuming that the crystal growth is the rate-determining step of zeolite crystallization, a simple equation describing the crystallization process has been developed. The equation depends on only two or, in the case of highly distorted crystallizations, on three parameters and so it allows a rational fitting even with a small set of experimental data, as is usually obtained during routine observations of zeolite syntheses. A derivation of this model from a second-order rate low with respect to the zeolite crystals and the amorphous gel is given. Applications of the model to experimental results are demonstrated for different examples including the crystallization of silicalite-1 in a fluoride system as well as inorganic MFI syntheses in the presence of boron, iron and chromium.