Synthesis Of Small Particle Size Y Zeolite Without Guide Agent

Since the1950s, the synthesis and industrial application of molecular sieve have always drawn high attention in academia and industry. In the50s, R. M. Milton and D. W. Breck successfully synthetized Y type molecular sieve with a medium SiO2/Al2O3molar ratio. Y type molecular sieve has been widely used in catalysis for its high stability, high activity, high resistance to deposition of carbon and sintering ability. With respect to conventional particle size Y molecular sieve, small particle size Y molecular sieve has superior catalytic performance. It has larger specific surface area, more catalytic activity center and faster intracrystalline diffusion rate and so forth.Isomorphous substitution of aluminium or silicon in zeolite structure can improve the adorption and catalytic activity of molecular sieve. Currently, there are few work on the synthesis of heteroatom Y zeolite. This work is of great importance in the development and application of small particle size heteroatom molecular sieves.In this paper, we synthetized high crystallinity NaY molecular sieve and heteroatom FeY molecular sieve based on the industrial grade silicon sol as the main raw material without any guide agent or organic template by means of hydro thermal synthesis. The results showed that using sodium aluminate as the aluminum source, H2O/SiO2=22.5, Na2O/SiO2=0.5, the gel aged at50℃for12hours, crystallined at100℃for12hours has the highest crystallinity and the morphology and particle size of the products meet the needs of the industrial need. We also synthetized FeY zeolite under the same conditions. It turned out that the incorporation of Fe not only can accelerate the speed of the crystallization, but also can control the transformation of the products. The crystallization temperature can be broadened from80℃to120℃.Furthermore, we also discussed the influence of H2O/SiO2, Na2O/SiO2, aging temperature, aging time, crystallization temperature, crystallization time and Fe content on the crystallinity and particle size of NaY and FeY zeolite systematically. In view of the little difference between the products aged at room temperature and50℃and energy saving, we discussed them at room temperature other than the influence of aging temperature.