METHOD FOR PRODUCING PRECIPITATED SILICA

PROBLEM TO BE SOLVED: To provide a new method for producing precipitated silica, particularly to provide a new method for producing precipitated silica used for a wide range of purposes such as a filler for paper making, a pigment for coated paper making, a filler for elastomer reinforcement and a carrier for medicaments. SOLUTION: The method for producing precipitated silica by reacting an alkali metal silicate with an acidifying agent includes; charging water or a slurry of precipitated silicic acid into a reaction tank; simultaneously adding an aqueous solution containing a pH buffer and the alkali metal silicate and an aqueous solution containing the acidifying agent under stirring; and reacting the alkali metal silicate with the acidifying agent while keeping the mixture at pH 6-8 to precipitate silica. COPYRIGHT: (C)2009,JPO&INPIT