以粉煤灰为原料采用两步法制备高纯度ZSM-5型沸石的研究

采用经碱熔融-离心提取处理后的粉煤灰为原料,经水热反应研究两步法合成高纯度ZSM-5型沸石的过程,探讨了碱灰比、焙烧温度对硅铝溶出量的影响,研究了碱度、晶化时间、晶化温度与硅铝比对合成ZSM-5型沸石的影响.结果表明:碱灰比为2.3∶1,焙烧温度为680 ℃时可获得最高的硅铝溶出量;当SiO2/Na2O =7(摩尔比),SiO2/Al2O3=45(摩尔比),晶化时间为68 h,晶化温度为180 ℃时可获得高纯度的ZSM-5型沸石.

Preparation of High Purity Zeolite ZSM-5 from Coal Fly Ash by Two-step Method

High purity zeolite ZSM-5 was synthesized by two-step method with coal fly ash pretreated by alkaline fusion and centrifugal extraction and hydrothermal method, the effects of alkali/ash and roasting temperature on the quantity of silicon aluminium dissolution were discussed, the influences of alkalinity, crystallization time, crystallization temperature and the Si/Al ratio on synthesis of zeolites were investigated.The results show that the highest silicon aluminium dissolution quantity obtained at 680 ℃, alkali/ash=2.3 and the high purity ZSM-5 zeolite synthesized at SiO2/Na2O=7, SiO2/Al2O3=45, crystallization time of 68 h and crystallization temperature of 180 ℃.