Patent ID: 8529651
Filing Date: 2013-09-10
Classification: C01B,C01F,C01P,C03C,C09G,C09K

Abstract:
1. A process for the production of an aqueous dispersion of a pyrogenically produced silica powder with a BET surface area of between about 90 to 300 m 2 /g, with a silica content in the dispersion of between 5 and 25 wt. %, comprising the steps: water is introduced from a receiving vessel to a rotor/stator machine, wherein the water is optionally adjusted to pH values of between 2 and 4 by adding an acid, and silica powder is introduced, using a feed device, into the shear zone between the slots in the rotor teeth and the stator slots of the rotor/stator machine, continuously or discontinuously and with the rotor/stator machine running, in a quantity such that a predispersion having a pH of between 2 and 4.5, and with a solids content of between 20 and 35 wt. % results, and, after all the silica powder has been added, the feed device closes and shearing continues in such a way that the shear rate is in the range of between 10000 and 40000 s then, by dilution, the predispersion is adjusted to the desired solids content of the dispersion while maintaining dispersing conditions, wherein the silica powder is not a doped silica powder.