Synthesis of Zeolite L and Effect of Synthesis Parameters on Crystallization

The high-crystallinity zeolite L was prepared with hydrothermal synthesis method. The optimal molar composition of the precursor gel is 5.4K2O∶5.7Na2O∶1Al2O3∶30SiO2∶500H2O, and crystallization was carried out at 175 ℃ for 24 h. As synthesized zeolite L samples were characterized by XRD, SEM. The results of XRD indicated that the prepared zeolite was the typical zeolite L and its characteristic peak value was high correspondingly. The results of SEM indicated that the cylindrical crystal diameter was about 1 μm and the particles of zeolite L were uniform basically. The synthesis condition of zeolite L should be strictly controlled for its limited crystallization range. The influences of hydrothermal synthesis conditions on crystallization of zeolite L were studied detailedly. The results indicated that crystallization was strongly affected by nSiO2/nAl2O3, nH2O/n(Na2O+K2O), nNa2O/n(Na2O+K2O), and aging could preferably reduce the size of crystals and improve the uniformity of the crystals.