PROCESS FOR THE PREPARATION OF AN AQUEOUS SUSPENSION OF FINELY-DIVIDED WATER-INSOLUBLE SILICATES CAPABLE OF CATION EXCHANGE

摘要

An aqueous suspension, suitable for further processing in detergents and cleaning agents, of a water-insoluble silicate of the general formula I: (Cat2O)0.8-1.3.(Al2O3).(SiO2)1.75-2.0 (I in which Cat is an alkali metal cation, is obtained by mixing alkali metal aluminate dissolved in water with alkali metal silicate dissolved in water in the presence of excess alkali. In order to meet the requirement for a process which, in a particularly short reaction time and with a high space-time yield, produces aluminium silicates of the abovementioned formula, which are extremely finely particulate but at the same time have a narrow particle size spectrum, the aqueous solutions, whose arithmetic overall composition in terms of their Al2O3 and their SiO2 content corresponds to the abovementioned formula, but which in total have at least 2.5 mol of Cat2O per mole of Al2O3 and at most 80 mol of water per mole of Al2O3 of the formula, are mixed rapidly and with vigorous stirring and the suspension obtained - before the solutions have been combined completely, if appropriate - is passed at least once - and at least for as long as the solutions have not been completely mixed - through a size reduction appliance.