Synthesizing,Characterization And Molding For 4A Zeolite For Gas Adsorption

The 4A zeolite have been applied in food,petrochemical industry,Sewage treatment,highpolymerchemical,cement,paper industry,detergent and building materials industry etc.Moreover,the use level of desiccant with 4A zeolite are increasing per year in industry,agriculture and people`s daily life.Natural zeolite reserves are very rich in China.Therefore,the research on the use of natural zeolite as raw material to synthesize 4A zeolite in order to reduce the cost has become one of the hot spots.Kaolin is natural mineral with layered structure,aluminosilicate as the main component.The purpose of this thesis is to synthesize 4A zeolite with high added value,low cost,high consumption,making full use of the natural mineral.This thesis focuses on the research of kaolin as raw material,through pretreatment to prepare 4A zeolite with high added value,low cost,large consumption and through thelateformingprocesstopreparespherical4Azeoliteadsorbent.The main content of this thesis:1.Study the method of Non-crystallization of kaolin through heat-acid,heat-alkali and high-temperature-burning etc.Employ ICP-AES and XRD to make quantitative and qualitative analysis.The results showed that the kaolin prepared through high temperature calcination has good performance and the operation is easy.2.Study the process for synthesis of 4A zeolite by using industrial raw material and study the practicability of recovery and utilization of mother liquid.4A zeolite were characterized by means of XRD,optical microscopy,static water absorption rate.Under the condition:SiO₂/Al₂O₃=2,Na₂O/SiO₂=1.6,H₂O/SiO₂=66,stirring speed of300 rpm.The feeding mode:solution I pour into solution II.Feeding time is 1min,gelling temperature is 60 centigrade,the crystallization temperature is 100 centigrade,the crystallization time is 5 hours under the condition of synthesis.the 4A zeolite powder with good quality can be synthesized.Mother liquid can be recycled.3.Study the synthesis method of 4A zeolite in laboratory,pilot and production stage.Using kaolin as raw material,investigate the parameters of the experimental and recovery of mother liquid.And finally,confirm the best conditions in the stage of production.The optimal experimental conditions in the production stage:heat up to60 centigrade,distribute the system evenly.The fixed Si O₂/Al₂O₃ is 2,Na₂O/SiO₂ is1.6,H₂O/SiO₂ is 66.,stirred for 2 hours,so that the system is evenly mixed.Fixed the proportion of 5%,adding seeds A,continue to be stirred for 1 hours.Heat the system up to 110 centigrade rapidly,crystallized for7h.Mother liquid can be recycled.4.The forming process was comprehensively discussed.Observing binder,solvent adhesive,molding agent,the effect of calcination temperature on 4A zeolite molding.The results showed that the optimum molding conditions:fixed speed is 30rpm,angle is 45 degree.Binder are clay and kaolin,sodium silicate as peptizator,calcination temperature is 500 centigrade.The stirring time is all into a ball,and continue to roll 1hours.The spherical adsorbent can be prepared with 5mm in diameter,60N for strength and 27%for static water absorption rate.