EFFECT OF AGING TEMPERATURE OF ALKALINE ALUMINOSILICATE AND SILICATE GELS ON THE KINETICS OF CRYSTALLIZATION OF ZEOLITE ZSM-5 AND SILICALITE-1

The temperature dependences of nucleation of zeolite ZSM-5 and silical ite-1 pass through extrema in the range from 110 degrees C to 120 degr ees C. Despite having the same crystalline structures, zeolite ZSM-5 h as a maximum and silicalite-1 has a minimum of nucleation in the tempe rature range mentioned. A method for preparation of single crystals of silicalite-1 up to 150 mu m in size has been developed. The compariso n of the curves of the temperature dependences of nucleation for zeoli tes Na-X, Na-A, and ZSM-5 shows that the positions of the maxima on th ese curves are determined by the type of the crystal structure of zeol ite.