Abstract: Precipitated silica with a sodium sulphate content of 4 to 18 wt. %, particularly with the physical-chemical data:______________________________________ Sodium sulphate content: 4-14 wt. % BET surface area (DIN 66131): 100-190 m.sup.2 /g DBP absorption (anhydrous) 208-250 g/100 g (DIN 53601, ASTM D 2414): 3.0-6.5 wt. % (DIN ISO 787/II) Oversize with >63 .mu.m .ltoreq. 10.0 wt. % ALPINE air-jet sieve >150 .mu.m .ltoreq. 0.1 wt. % >250 .mu.m .ltoreq. 0.01 wt. % ______________________________________It is prepared by introducing hot water into a precipitation vessel, with stirring, adding water glass, then heating the mixture and maintaining the temperature throughout the remainder of the precipitation period. Water glass and sulphuric acid are added simultaneously during this process. The precipitated silica is then separated from the suspension and the filter cake containing sodium sulphate is dried in a spray drier and ground.