由膨润土合成4A分子筛

Synthesis of 4A Zeolite from Bentonite

以天然膨润土为原料,采用一步碱溶水热法合成4A分子筛.探讨了不同的nNa2O∶nSiO2,nH2O∶nNa2O,nSiO2∶nAl2O3及合成时间与温度等工艺条件对4A分子筛结构与性能的影响.结果表明,当反应物料组成为nNa2O∶nSiO2=2,nH2O∶nNa2O=60和nSiO2∶nAl2O3=1.5时,于90℃反应6 h可以得到质量较好的4A分子筛,其产品晶形规整,晶粒粒径大多数小于2μm,钙离子(CaCO3)交换容量可达293 mg/g.

Zealite 4A was synthesized by a one-step alkali-dissolved hydrothermal method with bentonite as raw material. The effects of nNa2O：nsio2,nH2o：nNa2o,nsio2：nAl2O3,synthesis time and temperature on the properties of the products were investigated by means of XRD, SEM and calcium ion exchange capacity. The optimum conditions for synthesizing zeolite 4A are nNa2o：nsio2=2,nh2o：nNa2o=60,nsio2：nAl2o3=1.5 ,a crystallization temperature of 90℃ and a reaction time of 6 h. Under the optimal conditions, zeolite 4A with a high degree of crystallinity, a small granularity of particles （ most of the particle size of zeolite 4A was less than 2μm） and a high calcium ion（CaCO3） exchange capacity （293 mg/g） was obtained.