PROCESS FOR PRODUCING GRIT-FREE ZEOLITIC MOLECULAR SIEVES

    公开(公告)号:CA1057272A

    公开(公告)日:1979-06-26

    申请号:CA236911

    申请日:1975-10-02

    Abstract: The present invention provides a process for producing an A-type zeolite molecular sieve based on crystalline alumino silicates containing water of hydration and at least 99.5, by weight of particles having diameters smaller than 45 .mu.m by hydrothermal crystallization of an aluminate sodium tetrasilicate synthesis mixture in which the components of the synthesis mixture, which are in a molar ratio of SiO2 : Al2O3 less than 1.9 : 1 and in a molar ratio of water : alkali metal oxide of at least 30 : 1 are intimately mixed prior to the precipitation of an amorphous initial product, and after the crystallization the aluminium silicate suspension is tempered under cryatllizing conditions and is sheared during at least one of the crystallization and the tempering. The A-type zeolitic molecular seive so obtained has 99.5% of the particles with diameters below 45 .mu.m and a defined particle spectrum which makes is particularly useful as an ion exchanger, for example in the softening of water and as a phosphate substitute in detergents.

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