Patent ID: 7662306
Filing Date: 2010-02-16
Classification: B01J,C01B,C02F,D21H

Abstract:
1. A process for preparing an aqueous polysilicate microgel which comprises mixing (i) an aqueous solution of alkali metal silicate with (ii) an aqueous phase of silica-based material having a pH within the range of from 7 to 11, which is selected from the group consisting of silica-based sols, fumed silica, silica gels, precipitated silicas and acidified solutions of alkali metal silicates, and (iii) a metal salt other than an aluminum salt, wherein the metal salt is based on an alkali metal or alkaline earth metal and has an anion selected from of the group consisting of borate, nitrate, chloride, formate and acetate, wherein the polysilicate microgel has a specific surface area of at least 1000 m