FIELD: various technological processes.
SUBSTANCE: invention relates to precipitated silicon dioxide, a method for production thereof and use thereof. Precipitated silicon dioxide is characterized by the following physical and chemical parameters: CTAB-surface: not more than 115 m2/g, absorption of DOA: not less than 130 ml/(100 g), Ro-Tap>300 mcm: not less than 86%, V(d5-d50)/V(d5-d100): less than 0.66. Precipitated silicon dioxide is obtained by a method in which an aqueous solution of an organic and/or inorganic salt and/or silicate of an alkali or alkali-earth metal and/or an organic and/or inorganic base with pH not less than 9 is prepared. Into the initial solution while stirring and at temperature of 80–98 °C liquid glass and acidifying agent are simultaneously dosed for 60–120 minutes. Then addition of liquid glass is stopped and only acid is dosed in amount smaller than before to achieve pH value of mixture of 8.5–8.6. After that, the mixture is stirred for 45–200 minutes at a temperature higher than 85 °C. Acidified with sulfuric acid to pH 3.5–4.5, filtered, dried to loss during drying less than 8% and granulated.
EFFECT: improved dispersibility of silicon dioxide in rubber mixtures.
10 cl, 5 tbl, 3 ex
