Manufacture of synthetic zeolites

A method of preparing zeolite Y of high degree of purity and having a silica to alumina molar ratio of from greater than 3.0 up to about 6.2 which comprises (a) preparing an aqueous aluminosilicate reaction mixture by mixing an active hydrated sodium metasilicate, an alumina component and an Na.sub.2 O component or an active hydrated sodium metasilicate, an alumina component, an Na.sub.2 O component and other siliceous material, the reaction mixture having a composition expressed in terms of oxide molar ratios within the following ranges:

• ______________________________________ Na.sub.2 O/SiO.sub.2 SiO.sub.2 /Al.sub.2 O.sub.3 H.sub.2 O/Na.sub.2 O ______________________________________ (1) 0.28 - <0.30 8 - 10 20 - 70 (2) 0.30 - <0.31 8 - 12 20 - 70 (3) 0.31 - <0.32 8 - 14 20 - 70 (4) 0.32 - <0.34 8 - 16 12 - 90 (5) 0.34 - <0.40 7 - 40 12 - 120 (6) 0.4 - <0.7 5 - 50 12 - 120 (7) 0.7 - 1.0 31 - 50 12 - 120 ______________________________________
• the ratio of the active hydrated sodium metasilicate to any other siliceous material present in the aluminosilicate reaction mixture expressed on a molar silica basis lying within the range 1.0:0 to 1.0:6,000 and (b) agitating the aluminosilicate reaction mixture while heating the aluminosilicate reaction mixture at a temperature in the range of from 20.degree. C. to 120.degree. C. until a crystalline product is obtained.