PRECIPITATED SILICAS AND PROCESS FOR PRODUCING SAME

摘要

Precipitated silicas having thc following physiocochemical characteristic data: are produced by a process in which an original suspension of precipitated silica produced according to German Auslegeschrift No. 1,467,019 is diluted and an alkali metal silicate solution, sulphuric acid and water are simultaneously added, the pH value being kept constant between 7 and 9. The precipitated silicas are then filtered, washed, dried and micronized by means of a bowl mill. Because of their abrasiveness the precipitated silicas can be used as polishing agents and abrasives and the rnicronized silicas may be used as polishing agents, abrasives and thickeners in toothpastes.