Zeolites of faujasite structure with high silica content - from silicate solutions and faujasite

摘要

Title products have a reproducible SiO2/Al2O3 ratio of n where n is =6 and are made from alkaline silicate and aluminate solns. of the composition NaAlO2.k(NamH4-mSiO2).pH2O, after suspension in them of small quantities of faujasite crystal nuclei. The particle size distribution of the product can be closely controlled by appropriate choice of the correct quantities and sizes of the faujasite crystal nuclei. Advantages of the process is that it is cheap and easily available materials are used, a high reproducibility of the composition of the zeolites is possible, definite particle sizes are obtainable and an almost complete conversion of the starting material into faujasite is possible. The product is used in liquid and gas separations and in catalytic processes. Crystallisation temps. of 40-110 degrees C and crystallisation time of 16 to 165 hours are used.