US 4,303,628 A · Crystalline zeolite powder of type A (IV)

Abstract

There are produced crystalline zeolite powders of Type A with the composition 1.0.+-.0.2 M.sub.2/n O:Al.sub.2 O.sub.3 :1.85.+-.0.5 SiO.sub.2 .multidot.y H.sub.2 O where M is a metal cation, n is its valence and y has a value up to 6 with 50 weight % of the particles not over 4.9.mu. and with a particle spectrum ______________________________________ Fraction (.mu.) Portion (weight %) ______________________________________ <3 10 to 60 <5 55 to 95 <10 93 to 99 <15 96 to 100 ______________________________________ by hydrothermally crystallizing a SiO.sub.2, Al.sub.2 O.sub.3, Na.sub.2 O and water containing alkali aluminate, water, silicate synthesis mixture with an optional tempering step wherein in a given case during the crystallization or tempering step instead of stirring shearing forces are employed. The process comprises mixing with stirring (1) an aqueous alkali silicate solution and (2) an aqueous sodium hydroxide with a NaOH content of 0.1 to 500 grams/1 and or (3) aqueous sodium aluminate liquor which contains 0.1 to 100 grams/1 of Al.sub.2 O.sub.3 and 1 to 200 grams/1 of Na.sub.2 O, one of the components (1) and (2) or (3) being present in a container and the other being added thereto while preventing for a time of 10 to 30 minutes the formation of an insoluble gel having an SiO.sub.2 /Al.sub.2 O.sub.3 ratio of from 2 to 50:1, adding with stirring an aqueous sodium aluminate which contains 10 to 200 grams/1 of Al.sub.2 O.sub.3 and 10 to 250 grams/1 of Na.sub.2 O and having a temperature of 10.degree. to 100.degree. C. and allowing the thus obtained synthesis mixture to crystallize at a temperature within between 20.degree. and 175.degree. C. inside at least 15 minutes.

Claims12

Dependent claims

A process of preparing crystalline zeolite powder of Type A with the composition:

1.0.+-.0.2 M.sub.2/n O:Al.sub.2 O.sub.3 :1.85.+-.0.5 SiO.sub.2 .multidot.y H.sub.2 O
where M is a sodium cation, n is its valence and y has a value up to 6 with 50 eight % of the particle not over 4.9.mu. and with a particle spectrum:
______________________________________ Fraction (.mu.) Portion (weight %) ______________________________________ <3 10 to 60 <5 55 to 95 <10 93 to 99 <15 96 to 100 ______________________________________
comprising hydrothermally crystallizing a SiO.sub.2, Al.sub.2 O.sub.3, Na.sub.2 O and water containing alkali aluminate, water, alkali silicate synthesis mixture, said process including the steps of mixing with stirring (1) an aqueous sodium silicate solution containing 50 to 150 grams of Na.sub.2 O/l and 200 to 450 grams of SiO.sub.2 /l and (2) aqueous sodium aluminate liquor which contains 0.1 to 100 grams/l of Al.sub.2 O.sub.3 and 1 to 200 grams/l of Na.sub.2 O, one of components (1) and (2) being present in a container and the other being added thereto while preventing for a time of 10 to 30 minutes the formation of an insoluble gel having an SiO.sub.2 /Al.sub.2 O.sub.3 ratio of from 2 to 50:1, adding in two steps with stirring an aqueous sodium aluminate which contains 10 to 200 grams/l of Al.sub.2 O.sub.3 and 10 to 250 grams/l of Na.sub.2 O and having a temperature of 10.degree. to 100.degree. C., the speed of addition of the second step being 2 to 10 times higher than in the first step, and allowing the thus obtained synthesis mixture to crystallize at a temperature within between 20.degree. and 175.degree. C. for at least 15 minutes.

1 more element

Dependencies are inferred from the claim text.

Crystalline zeolite powder of type A (IV)

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Crystalline zeolite powder of type A (IV)

Life of this patent

Abstract

Claims12