Influence of anions on the kinetics of zeolite A crystallization: a population balance analysis

Kinetics of nucleation, crystal growth and entire process of crystallization of zeolite A in the presence of different sodium salts were analyzed by population balance method. Both the rate of crystallization and rate of crystal growth of zeolite A increase with increasing concentration of sodium sulfate dissolved in the liquid phase of the crystallizing system, but equimolar amounts (with respect to Na+ ions) of different sodium salts influences the rate of crystal growth only on the extent which can be attributed to experimental errors characteristic for this type of experiments. Thus, it was concluded that only sodium ions and not the associated anions influence the rate of crystal growth of zeolite A. Insensibility of the particulate properties of the crystalline end products on the presence of different anions supports this conclusion was explained by the "memory" effect of specially prepared amorphous aluminosilicate gel precursors. (C) 2004 Elsevier B.V. All rights reserved.