Process for the production of precipitated silica

摘要

Precipitated silica which has a BET surface area of 10-130 m2/g, a CTAB surface area of 10-70 m2/g , an average particle diameter of 5-20 mu m, a Cu abrasion value in a 10% glycerol dispersion of 4-50 mg and thickening behavior in a CMC solution (20% dispersion) of 300-3500 mPaxs, is produced by simultaneously adding alkali silicate (weight modulus SiO2:alkali oxide=2.5-3.9:1) and a mineral acid to an initial amount of water which has been adjusted to a pH value of 7.0 to 9.9 or 10.0 to 10.7 by the addition of water glass, holding the pH value constant between 7.0 and 9.9 or 10.0 to 10.7 during addition, wherein the initial precipitation temperature is 50 DEG -90 DEG C. and an increase in viscosity occurs after at most 25% of the duration of precipitation, adjusting the pH value to /=160 g/l to 240 g/l, has been reached, separating the solid by filtration, washing, drying and grinding it. The precipitated silica may be used as an abrasive and/or thickening component in toothpastes.