Patent ID: 6685907
Filing Date: 2004-02-03
Classification: C01B,C01P,D21H

Abstract:
A process for producing silica particles, comprising the steps of:(1) mixing an aqueous alkali silicate solution with first particles difficultly soluble in an alkali and soluble in an acid, so as to form a first slurry containing said first particles; (2) neutralizing said first slurry with a mineral acid to prepare a second slurry containing second particles wherein silica is deposited on said first particles; and (3) adding a mineral acid to said second slurry to dissolve said first particles and form a third slurry containing silica particles, wherein, in step (2), 10 to 50% of said mineral acid necessitated for neutralizing said alkali silicate solution is added to said alkali silicate solution at 20 to 60Â° C., then the resultant slurry is heated to a temperature of 70Â° C. or higher, and the balance of said mineral acid necessitated for the neutralization is added.