预成型高岭土干胶转化合成NaY型分子筛

通过干胶转化法制备了整体式NaY分子筛,采用XRD、SEM及XRF分析表征原料及产物,系统考察了合成体系的n（SiO₂）/n（Al₂O₃）、n（Na₂O）/n（SiO₂）、水量、晶化温度和晶化时间对整体式NaY分子筛制备的影响。结果表明,合成体系n（SiO₂）/n（Al₂O₃）=7.5时,骨架硅铝比（二氧化硅与氧化铝物质的量比）最大为6.12;n（Na₂O）/n（SiO₂）逐渐增大,整体式NaY分子筛结晶度逐渐升高,当n（Na₂O）/n（SiO₂）增至0.35时,会导致P型分子筛的生成;晶化温度从90 ℃逐渐增至120 ℃时,整体式NaY分子筛结晶度也随之升高;在110 ℃下晶化20 h,产物的结晶度达到98%并趋于稳定。干胶转化制备整体式NaY分子筛必须有水的参与,n（H₂O）/n（SiO₂）为4.2左右对反应物的成型及整体式NaY分子筛的晶化较为适宜。

Synthesis of NaY zeolite from preformed kaolin by dry gel conversion

Monolithic NaY zeolite was synthesized by dry gel conversion method.XRD,SEM and XRD were used to study the raw materials and products.The influences of n（SiO₂）/n（Al₂O₃）,n（Na₂O）/n（SiO₂）,water content,crystallization temperature and crystallization time on the preparation of monolithic NaY zeolite were systematically investigated.Experimental results showed that when n（SiO₂）/n（Al₂O₃） of synthesis system was 7.5,the n（SiO₂）/n（Al₂O₃） of framework was 6.12.The crystallinity of the NaY zeolite increased with the amount of n（Na₂O）/n（SiO₂） firstly.If n（Na₂O）/n（SiO₂） was above 0.35,the NaY zeolite would turn to P zeolite.When the crystallization temperature increased from 90 ℃ to 120 ℃,the crystallinity of product increased accordingly.After crystallization at 110 ℃ for 20 h,the crystallinity of product was 98% and stated stable.Water was the key factor in the process of dry gel conversion.When the n（H₂O）/n（SiO₂） reached about 4.2,it was good for the synthesis of NaY zeolite.