沸石分子筛的生成机理与晶体生长(Ⅵ)——NaY型沸石生成的液相机理与其组成Si/Al比的非均一性

THE MECHANISM OF THE FORMATION AND THE CRYSTAL GROWTH OF MOLECULAR-SIEVE-ZEOLITE(Ⅵ)——Liquid Phase Mechanism Followed arid the Heterogeneity of Compositions Si-Al Ratio in the Course of the Formation of NaY Type Zeolite

应用化学分析、小角激光光散射与电子衍射以及X-射线衍射分析证实了NaY型沸石的形成遵循液相转变机理与形成过程中沸石骨架组成Si/Al此变化的非均一性。

The changes in concentrations of the components SiO_(2) and A1_(3)O_(3) and in weight average molecular weight(Mw)of SiO_(3) as a function of the crystallization time in the liquid phase of gel were investigated by using chemical analysis and low angle laser light scattering methods respectively.Results have shown that the formation of NaY type zeolite follows the liquid phase mechanism.The existence of the microcrystal of NaY type zeolite in the liquid phase of gel in the course of the crystallization of NaY type zeolite was proved by the experiment of electron diffraction.By means of determining by X-ray powder diffraction the silica-alumina ratio and its change of NaY type zeolite presented in the crystal phase at the intervals of crystallization time,it has been found that the silica-alumina ratio of the NaY type zeolite formed in the course of crystallization decreases gradually with the rucleation and crystal growth of NaY type zeolite,which show the heterogeneity of the composition silica-alumina ratio of the NaY type zeolite formed in the course of crystallization.