2 surface area of approx 125 m 2 g ks 404 silica from akzo with an n 2 surface area of approx 175 m 2 g ______________________________________test unit standard______________________________________tensile stress mpa din 53 504compression set b astm d 395loss angle tan u03b4 din 53 513din abrasion mm sup 3 din 53 516firestone ball rebound ad 20 405mooney viscosity me din 53 523 524goodrich flexometer astm d 623 a______________________________________ production of a silica according to the invention with an n 2 surface area in the range 100 m 2 g 43 5 m 3 of hot water is introduced into a vat and customary commercial sodium waterglass weight modulus 3 42 density 1 348 is stirred in in a quantity such that a ph of 8 5 is achieved while maintaining a precipitation temperature of 88 u00b0 c and ph 8 5 16 8 m 3 of the same water glass and sulfuric acid 96 are simultaneously added within 150 minutes from opposite positions a solids content of 100 g l is produced further sulfuric acid is then added until a ph of lt 5 is achieved the solids are separated in presses washed and the pressed paste dried by spray.