预成型高岭土干胶转化合成NaY型分子筛

Synthesis of NaY zeolite from preformed kaolin by dry gel conversion

通过干胶转化法制备了整体式Na Y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Na Y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Na Y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Na Y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Na Y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Na Y分子筛的晶化较为适宜。

Monolithic Na Y 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 Na Y 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 Na Y zeolite increased with the amount of n(Na2O)/n(SiO2)firstly.If n(Na2O)/n(SiO2)was above 0.35,the Na Yzeolite 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 Na Y zeolite.