Analysis of the growth of molecular sieve zeolite NaA in a batch precipitation system

A reaction engineering model for the synthesis of molecular sieve zeolite A has been improved by including a nucleation step and solving the complete model numerically instead of using the quasi-steady state approximation. It is shown that experimental kinetic curves can be simulated by this model, and that particle nucleation accounts for the early stages of synthesis. The population balance also has been applied to zeolite A synthesis for the first time. Particle growth rates were determined from this analysis, which shows that the growth rate for zeolite A decreases at larger sizes. Finally, it is shown that the silica-to-alumina ratio in the batch composition may be used to control the product crystal morphology.