The Synthesis And Characterization Of Zeolite REY

Zeolite Y is the traditional catalytic and adsorbing material, which has the advantages of uniform pore size, high catalytic property, good stability and so on. Rare earth ions can improve the activity and stability of Y type molecular sieve, so it is widely used in catalytic cracking, hydrocracking and isomerization. In order to synthetize REY molecular sieve that has both precipitation of rare earth oxide and rare earth existing in the skeleton structure and zeolite Y at the same time, this paper designs a kind of hydrothermal synthesis of zeolite REY by one step.Firstly, this article uses the single factor experiment method to study main influence factors of to zeolite Y synthesizing by water glass as the silicon source, and gets the optimal synthetic conditions:aging temperatures is 65 ?, aging time is 45 minutes and better sequence of mother liquor is that firstly mixing sodium hydroxide, sodium silicate and guiding agents, then adding the sodium aluminate solution. In the process of crystallization of zeolite Y, the gel dissolve and rearrange on the surface of solid liquid phase, gradually form the structure unit, further form unique frame structure. XRD, SEM, TEM and BET tests find that the product of hydrothermal synthesis basically has the morphology, phase and channel structure of zeolite Y.Then using zeolite Y as basical materials, this paper studies the technological process of synthesis of zeolite REY by ion exchange method, and analysis the characterization of REY molecular sieve. The best process conditions of ion exchange method synthetic conditions are as follows:the addition amount of cerium nitrate is 15g/L, the temperature of ion exchange is 95 ?, the time of ion exchange is 60 minutes, choose the double exchanging and roasting process, and then in-depth ion exchange used ammonium can reduce the sodium content greatly. XRD, TEM and BET tests find that the introduction of the rare earth elements has not changed the basic structure of zeolite Y.At last, the paper designs the hydrothermal synthesis of zeolite REY by only one-step. Its best process conditions are as follows:selecting the order of mixing sodium hydroxide, sodium silicate and guiding agents first, then add the sodium aluminate solution, the last join cerium nitrate solution is optimal and the amount of cerium nitrate is 1.5g. XRD, TEM and BET tests find that:REY molecular sieve still has the same phase structure and microstructure of zeolite Y. Rare earth elements can exist in zeolite REY by two different forms, one is into the skeletal structure of molecular sieve, anorher is the independent precipitation of rare earth oxide. BET test finds that the synthetic product contains microporous structure, but its adsorption performance is less than zeolite NaY. In addition, joining the rare earth complexes with organic matter in synthetic system can get uniform grain size and distribution but has a certain negative impact for the crystallinity and adsorption performance of zeolite REY. After pickling, the sodium content is decreased obviously, and deposit of rare earth distributes evenly, but segmental rare earth element breaks away from the skeleton.