多种类型粘土混合料合成4A分子筛的研究

Study on Synthesis of 4A Zeolite by Different Types of Clay Mixtures

采用三种不同化学组成的粘土,通过配方计算,配制成具有不同硅铝比n(SiO2)/n(Al2O3)的混合料,经湿法加碱煅烧活化、水热成胶与晶化过程,合成出了4A型分子筛。用XRD和SEM对产物进行了表征,探讨了粘土原料硅铝比、碱度等因素对合成4A分子筛的影响。结果表明,在混合料硅铝比及其他工艺条件相同情况下,粘土类型与4A分子筛硅铝比相近时,其混合料合成的分子筛结晶程度高且杂晶少。当混合料硅铝比设计为1.8~2.0,碱浓度为2.8 mol/L时,合成的分子筛较为理想。

With three different chemical compositions of clay as raw materials,4A zeolite was synthesised by formula calculation and a series of process including wet-method alkalinizing calcinations, hydrothermal preparation and crystallization. Influencing factors including alkali concentration and Si/Al of clay raw materials were mainly discussed. The products were characterized by XRD and SEM. The results showed that, when the clay had similar Si/Al under the same Si/Al of mixtures and technological conditions,4A zeolite with high crystallinity and low impurity can be synthesized. The results also showed that products were better with Si/Al of mixtures at 1.8~2.0 and alkali concentration at 2.8 mol/L.