Process for producing grit-free zeolitic molecular sieves

Abstract From the Canadian patent

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 µm 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 …