METHOD OF SILICON DIOXIDE PRODUCING Russian patent published in 1995 - IPC

FIELD: inorganic chemistry. SUBSTANCE: SiO₂ is precipitated by addition of sodium or potassium silicate solutions to solutions of ammonium salts of sulfuric, hydrochloric, carbonic, nitric, formic or acetic acids at the ratio of total SiO₂ adding with silicate to the total content of ammonium salt followed by treatment of hydrogel prepared. Precipitation conditions: temperature is 35-95 C, rate is 100-270 g SiO₂/l_susp·h and additional treatment of hydrogel SiO₂ after precipitation with ammonium salt solutions taken from the order: (NH₄)₂SO₄, or NH₄Cl, or (NH₄)₂CO₃,, or NH₄HCO₃, or NH₄NO₃,, or NH₄HCO₂,, or NH₄CH₃CO₂.. EFFECT: improved method of producing. 2 cl, 1 tbl