A SIMPLE-MODEL FOR THE KINETIC EVALUATION OF ZEOLITE CRYSTALLIZATION PROCESSES

Assuming that the crystal growth is the rate-determining step of zeoli te crystallization, a simple equation describing the crystallization p rocess 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 da ta, as is usually obtained during routine observations of zeolite synt heses. A derivation of this model from a second-order rate law with re spect to the zeolite crystals and the amorphous gel is given. Applicat ions of the model to experimental results are demonstrated for differe nt examples including the crystallization of silicalite-1 in a fluorid e system as well as inorganic MFI syntheses in the presence of boron, iron and chromium.