稀土交换量对Y型分子筛结晶度测定值的影响

EFFECT OF RARE EARTH CONTENT ON THE CRYSTALLINITY OF ZEOLITE BY XRD ANALYSIS

采用XRD方法对稀土交换Y型分子筛的结晶度进行测定。结果表明:随着稀土交换量的增加,分子筛的结晶度明显降低;结晶度变化并不是由分子筛晶体结构变化引起的,而是稀土离子使XRD法测量分子筛结晶度产生偏差造成的;焙烧使稀土在分子筛中的分布更均匀,稀土离子的影响减弱,因此经过焙烧的含稀土分子筛的结晶度测量值下降较少;通过数学拟合,建立了分子筛稀土含量与结晶度变化量之间的定量关系。

The crystallinity of rare earth （RE） exchanged zeolite Y is determined by XRD meth od. Results show that with the increase of RE contents in zeolite,the zeolite crystallinities decrease significantly,and the changes of crystallinity are not reflecting vary from zeolite crystal structure,just because the determination of zeolite crystallinity by XRD is disturbed by the existence of rare earth cations. The distribution of RE in zeolite trends to be even during calcination,thus the effect of RE cations on the determination of crystallinity is less for calcined RE-exchanged zeolite Y. By mathematical fitting,a formula is established between the changes of zeolite crystallinity and the contents of rare earth oxide in zeolite.