The Application Of Water Soluble Polymer To Synthesize High Silica Zeolitey

Water soluble polymers are possessed of kinds of functional group and molecular weight. Used in synthesizing zeolites, water soluble polymers can shorten crystallization times, decrease the particle sizes and increase the surface areas. In this paper, we reported directly synthesis of high Si/Al ratios zeolite Y with silica-alumina sphere as raw material. Water soluble polymers were also used as additives in synthesizing high Si/Al ratios zeolite Y, the influences were discussed detailedly. The samples were characterized by XRD, SEM, FT-IR and chemical analysis.Zeolite Y is main active component in fluid catalytic cracking catalysts. The property of zeolite Y deponds on Si/Al ratios. Apart framework of zeolite Y may collapse due to dealumination, so directly synthesis of high Si/AL ratios zeolite Y can effectively avoid this defect.In the system of Na₂O-Al₂O₃-SiO₂-H₂O, silica-alumina sphere as main raw material, silica and alumina may dissolve together during the synthesis, so high Si/Al ratios zeolite Y can be synthesized directly by employing hydrothermal method. The Si/Al ratios of obtained samples can reach 3.1, which was higher than industrial zeolite NaY product (Si/Al=2.5). The morphology of synthesized sample was the congeries of the crystals with diameter of 100-300nm, which was smaller than industrial zeolite NaY. Under the same conditions, the thermal stability of synthesized high Si/Al ratios zeolite Y and industrial samples were studied. The framework of industrial sample collapsed at 500℃, however, collapse temperature of synthesized sample can reach 850℃. Obviously, synthesized zeolite Y possessed better thermal stability.Different kinds of water-soluble polymers had been applicated in this system. The data of XRD proved that the phase of zeolite Y can be kept with polyethylene glycol-6000, PVP and polyacrylic acid as additives. However, polyvinyl pyrrolidone and gelatin had adverse influences on synthesis of zeolite Y. Polyvinyl pyrrolidone led the phase to zeolite P, The obtained product was amorphous with adding gelatin.Among the chosed water soluble polymers, polyethylene glycol-6000 has obviously influence on the crystallization of zeolite Y, which increased relative crystallinity, shortened crystallization time and the particle sizes were smaller than usual. When the crystallization time shortened to 2 days, the best synthesized condition was n(Na₂O): n(Al₂O₃): n(SiO₂): n(H₂O): n(R)= 2.8: 1.0: 13.5: 190: X, v(reaction agent)/v(H₂O) = 0.17, X = m(R)/v(H₂O) = 0.06. The relative crystallinity of zeolite Y was 90% .