PROCESS FOR THE PRODUCTION OF A CRYSTALLINE ZEOLITIC MOLECULAR SIEVE OF TYPE A

摘要

1525782 Type A zeolites DEUTSCHE GOLDUND SILBER-SCHEIDEANSTALT 6 April 1976 [18 April 1975] 13850/76 Heading C1A [Also in Division C5] A particulate crystalline Type A zeolitic molecular sieve is of composition: 1À0Œ0À2M 2 0:Al 2 O 3 : 1À85 Œ0À5 Si0 2 Ày H 2 0 (in which y is 0-6) at least 99À5 wt. per cent of the particles having a diameter less than 30 Ám at least 90 wt. per cent less than 10 Ám and at least 50 wt. per cent not more than 6À5 Ám. The zeolite is prepared by (1) stirring together an aqueous alkalimetal silicate solution and an aqueous alkali metal aluminate liquor of low concentration (as defined); (2) allowing the premix obtained to harden into a gel; (3) adding an aqueous alkali-metal aluminate liquor of higher concentration to the gel at 10-100‹ C with stirring; (4) allowing the mixture obtained to crystallize at 20-175‹ C for at least 15 minutes, and optionally (5) tempering. The zeolite also has a characteristic particle size distribution.