| 摘要 |
Production of precipitated silica comprises adding acid to a silicate solution with a silicon oxide (SiO2) content of below 15 g/l to adjust the pH to 7-8, simultaneously adding silicate and acid in amounts so that the pH remains at between 7 and 8 and the SiO2 content remains at or below 35 g/l, adding acid to adjust the pH to 3-6.5, filtering the mixture and drying the filter cake. Independent claims are also included for: (1) an aqueous silica composition obtainable after disintegration of the above filter cake; (2) precipitated silica with a water uptake below 6% produced by the above process or by spray drying the composition of (1), and (3) a pharmaceutical composition comprising silica produced by the above process or by spray drying the composition of (1). |
