PROCESS FOR PREPARING PRECIPITATED SILICAS, PRECIPITATED SILICAS AND THEIR USE

摘要

Provided are a process for preparing precipitated silicas, precipitated silicas and their use as a filler in an elastomer. The process comprises the steps of: preparing initial charge; simultaneously metering silicate and acidifying agent into the initial charge and reacidifying the precipitation suspension to a pH of 2.5 to 6.0, wherein the silicate used has metal oxide of 4wt% ~7wt% and silicon dioxide of 14wt% ~23wt% and the acidifying agent is selected from the group consisting of sulphuric acid of 90wt%~98.5wt%, hydrochloric acid of 34wt%~42.7wt%, nitric acid of 60wt%~68wt%, phosphoric acid of 80wt%~100wt%, carbonic acid or CO2 and sodium hydrogen sulphite or SO2.