分子筛成核与晶体生长动力学研究 Ⅰ.非自成核体系中修正的 Lechert 模型

KINETIC STUDY ON ZEOLITE NUCLEATION AND CRYSTAL GROWTH Ⅰ Modified Lechert Model in the System of Non spontaneous Nucleation

通过引入凝胶和晶体介质对液相扩散速率的修正因子，在非自成核体系得到修正的Ｌｅｃｈｅｒｔ分子筛晶体生长动力学模型，给出了诱导期和晶体快速生长期的计算公式，表明了晶种量对诱导期影响的特殊性。与Ｌｅｃｈｅｒｔ模型相比，该模型不仅对Ｙ型、ＺＳＭ－５型和Ｌ型实验晶化曲线的前期和后期进行了较好的拟合，且可通过Ｙ型分子筛晶体生长曲线定性推断导向剂中初始晶种的半径、晶种量和颗粒密度随导向剂老化条件的变化规律。

A crystal growth model of zeolite in the system of non spontaneous nucleation was developed,by introducing correction coefficients of the gel and crystal to crystal growth rate The induction period and rapid growth period were formulated The effect of amount of seeds on the induction period was different from that on the rapid growth period The fact that the calculated curves of zeolite Y、L and ZSM 5 were consistent with the experimental results showed that the present model was of value to explain the process of crystallization particularly the induction period and the end stage The predicted values of the amount and size of seeds with present model were more truely accessible to experimental results than those with Lechert model,especially for synthesis of NaY zeolite with initiating agent