Exploratory Study On Synthesis Of NaY Molecular Sieve

Y-zeolite and new synthesized inorganic porous materials in recent years have beenapplied in many fields including catalysis, adsorption, ion-exchange and so on. There aresome disadvantages for synthesizing zeolite from chemical reactants, such as the high cost,the excessive waste and unfriendly to the environment. While zeolites are synthesized frominorganic non-metallic mineral materials, such as kaoline, diatomite etc, but the mineralmaterials in those research needed to be calcined at high temperature, which costs more inenergy and equipment.In this paper we have analyzed plenty of republications about the synthesis andapplication of Y-zeolite, studied the relationships between the yield of NaY zeolite and otherinfluence factors and discussed the different effects on the crystallinity, size, thermal stability,structure of zeolite by different conditions.The NaY zeolite crystal had been synthesized from industrial materials by directcrystallization. The crystal synthesized had been characterized by XRD, IR, SEM and etc.The different influences on the properties and yield of zeolite crystal, such as molar ratio ofreactants, temperature, react time and additives, had been discussed systematically.The results indicate that when SiO₂/Al₂O₃ is 7.0, a low degree crystallinity of NaYzeolite achieved when increased the SiO₂/Na₂O or H₂O/Na₂O; the crystallinity of NaY zeolitefirst became higher gradually and then lower when prolonging the react time; adding sucrosewould obtain a relatively high crystallinity.When SiO₂/Al₂O₃ is 7.0, the yield increases about 0.8% averagely whenSiO₂/Na₂O(mol/mol) plus 0.04; the yield increases with prolonging crystallizing time but thescale of increase tends to little; adding sodium tetraborate would increase the yield and theratio of increase is about 5.51%.The thermal stability of zeolite also has been discussed, The thermal analysis indicatesthat the main weight losses occur under 300℃. There is a endothermic peak at about 200℃,which ascribes to the dehydration in zeolite. There is no other thermal reactions under 900℃,which means the product has a favorable thermal stability.