Investigation On Phase Transformation Of Mordenite

The metastable nature of many crystalline aluminosilicate zeolites is well known and documented. In fact, the metastable characteristics has been proposed as an explanation of the nonexistence in nature of many of the zeolites that have been synthetically prepared. This metastability of zeolites is observed in the transformation from one crystal structure to another and in differences in ordering within a given crystal structure. The rate at which the metastable zeolite changes to an equilibrium or more stable stucture is dependent upon the intrinsic properties of the zeolite and the chemical environment in which it exists.This paper is focused on the transformation of mordenite under different conditions based on analysis of XRD, XRF, H2O adsorption and chemical analysis method. The procedure of the transformation, the mechanism and the effect on the rate of transformation of mordenite from chemical environment were studied. Under alkaline conditions, mordenite transforms into zeolite NaP in a direct way and subsequently transforms into anacime. In a solution of sodium hydroxide containing alumium, zeolite A and faujasite can be formed from mordenite. And the transformation follows a solution-mediumed mechanism. The higher the temperature , the faster of the rate of transformation; the denser the concentration of alkaline, the faster of the rate of transformation; the longer of crystalline time, the easier of transformation from mordenite into other zeolites which have more themordynamical stability. Furthermore, faujasite with higher silica-to-alumina has been synthesized from mordenite.