Abstract
MFI-type zeolites were synthesized by the rapid crystallization method in 2 h. The synthesis parameters were studied briefly using a statistical method, and the pH of the initial hydrogel was found to be the most critical parameter under the synthesis conditions used and the crystallization time constrain. The physicochemical properties of the zeolite products were studied and found to have some advantages over conventionally synthesized zeolites. The thermal stability was found to decrease with increasing Si/Al ratio contrary to what was widely accepted. It was speculated that high concentrations of defect sites exaggerated by the rapid crystallization time may be responsible for the trend of thermal stability.