ALUMINOSILICATE SOLS AND POWDERS

摘要

(IC 6287-B) ALUMINOSILICATE SOLS AND POWDERS An amorphous aluminosilicate sol with uniform size particles and a porous amorphous aluminosilicate powder composition useful as a catalyst in petroleum cracking is prepared by a process comprising (1) preparing a sol of discrete colloidal particles of uniform size within the range of from 2 to 87 nanometers, the surface of the particles consisting of a coating of an aluminosilicate at least 0.5 nanometer in thickness, by separately and simultaneously adding a sol of silica or a solution of sodium or potassium silicate and a solution of sodium or potassium aluminate to a heel sol of uniform-sized colloidal particles of aluminosilicate, silica, or one or more refractory metal oxides at a certain rate of addition and at a constant pH in the range of 9 to 12 and a temperature of 50.degree. to 100.degree.C to deposit or coat aluminosilicate onto the surface of the heel sol particles, (2) ion exchanging the sodium or potassium ions of the sol from (1) for ammonium ions, (3) optionally removing the ammonium ions partially or completely with one or more metal ions described herein selected from Groups I to VIII of the Periodic Table, and (4) removing water from the sol without gelling so that the particles become uniformly packed into aggregates having pores of substantially uniform size and coating said powder with a surface layer 0 to 15% by weight of a metal or metal oxide, said powder having a specific surface area of 30 to 750 m2/g, a bulk density of 0.5 g/cc or more and substantially uniform size pore diameters of from 20 .ANG. to 250 .ANG., with pore diameters of 20 .ANG. to 45 .ANG. having a uniformity such that at least 90% of the pore volume is made up of pores of from 0.6D to 1.4D and pore diameters of 45 .ANG. to 250 .ANG. having a uniformity such that at least 80% of the pore volume is made up of pores of from 0.6D to 1.4D, where D is the median pore diameter.