Abstract: Alkali aluminum silicates, particularly a zeolitic molecular sieve powder with an average particle diameter of less than 10.mu. and having the portion of particles with a particle size above 45.mu. being less than 1 weight % are prepared by hydrothermal crystallization of an alkali aluminate-silicate mixture, separating the crystallization product from the mother liquor and drying with the proviso that the aqueous medium surrounding the crystallization product is adjusted to a pH value between 8.5 and 11 prior to the drying. The product is used as an ion exchanger, e.g., in dehardening water, particularly as a phosphate substitute in washing, rinsing and cleansing agents.

Abstract: There are provided alkali aluminum silicates having a hydrophilic surface. They are prepared by mixing a crystalline, ion-exchanging alkali aluminum silicate with a hydrophilic material, preferably ortho-phosphoric acid or an alkali ortho phosphate.

Abstract: A crystalline zeolitic molecular sieve 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 . y H.sub.2 O where M is a metal cation, n its valence and y has a value up to 6 is prepared having particles with at least 99.5 weight % below 30.mu. diameter, as well as at least 90 weight % under 10.mu. and with 50 weight % below 6.5.mu. by hydrothermal crystallization of an alkali-aluminate silicate by pouring together an aqueous alkali silicate solution and a slightly concentrated aqueous alkali aluminate liquor, in a given case with simultaneous stirring in a receiver, allowing the synthesis premixture to solidify to a gel, adding to this gel a more highly concentrated aqueous alkali aluminate liquor at a temperature between 10.degree. and 100.degree. C. while stirring, allowing the thus obtained synthesis mixture to crystallize at a temperature between 20.degree. and 175.degree. C., preferably 100.degree. C.

Abstract: There are provided alkali aluminum silicates having a hydrophilic surface. They are prepared by mixing a crystalline, ion-exchanging alkali aluminum silicate with a hydrophilic material, preferably ortho-phosphoric acid or an alkali ortho phosphate.