| 摘要 |
A method for the preparation of finely-divided, water-insoluble, aluminosilicate cation-exchangers with a narrow particle size spectra suitable for detergent formulations comprising: (1) agitating a water-dissolved alkali metal silicate at a temperature of from 55 DEG C. to 95 DEG C. (2) mixing therewith at a temperature of from 55 DEG C. to 95 DEG C. over a period of from three seconds to five minutes with vigorous agitation, a water-dissolved alkali metal aluminate, in the presence of an excess of alkali to give a suspension of a silicate compound containing bound water and having a calcium binding power, when measured at 22 DEG C. by the Calcium Binding Power Test Method, of at least 50 mg CaO/gm of anhydrous active substance, and having the formula, bound water not shown, (M2O)0.8-1.3.Al2O3.(SiO2)1.75-2.0 wherein M represents an alkali metal, wherein said reactant solutions when mixed have a composition corresponding to the desired Al2O3 and SiO2 amounts of the above formula, with a ratio of from 3.2 to 4.4 mols M2O/mol Al2O3 and a ratio of from 70 to 85 mols of water/mol Al2O3, (3) maintaining said silicate compound suspension after said mixing step is completed, for a period of from two to twenty minutes under the agitation and temperature conditions of said mixing step, (4) rapidly heating said silicate compound suspension at least 5 DEG C. above the temperature of said mixing step to a temperature of from 60 DEG C. to 100 DEG C., (5) allowing said silicate compound suspension to crystallize at said elevated temperature of from 60 DEG C. to 100 DEG C. while agitating sufficiently to keep said suspension flowable, (6) adjusting said crystalline silicate compound suspension to a pH of below 12.5, and (7) recovering said crystalline silicate compound. |
