Patent ID: 7524478
Filing Date: 2009-04-28
Classification: C01B,C01P,C08K

Abstract:
1. A process for preparing a low water-uptake precipitated silica, comprising the following successive steps: (a) producing an initial feedstock comprising a silicate, the silicate concentration in the feedstock, expressed in SiO (b) adding an acidifying agent to form an acidified feedstock, bringing the pH of the medium to a value of between 7 and 8; (c) simultaneously adding a silicate and an acidifying agent to the feedstock resulting from step (b) to form a reaction medium, the respective amounts of added silicate and acidifying agent over time being specifically selected such that, throughout the entire addition: (d) adding an acidifying agent to the reaction medium resulting from step (c), so as to bring the reaction medium to a pH of between 3 and 6.5; and (e) filtering the resulting aqueous silica dispersion, then drying the filter cake obtained at the end of the filtering step.