Physicochemical Studies on the Crystalline Aluminosilicates. III. : Influence of the Concentrations of Starting Mixture in the Crystallization Process

Examinations were made on the conditions for crystallization of sodium aluminosilicate. At the temperature of 80°, with A-type zeolite, rate of crystallization was faster, the higher the concentration of the starting mixture, and crystallization was effected in 30 minutes with a concentration of 0.5 mole/L. Degree of crystallization was found to be unaffected by the concentration of the starting mixture. On the other hand, with the X-type zeolite, rate of crystallization was faster with higher concentration of the starting mixture but the degree of crystallization decrease with concentrations above 0.25 mole/L. A concentration of about 0.2 mole/L. was therefore found to give zeolite with the best degree of crystallization. Evaluation of the degree of crystallization by X-ray powder diffraction showed that there is a good correlation in the crystallization degree between that obtained from the height of the diffraction peak and that obtained from the peak area.