CONCENTRATED SUSPENSION OF PRECIPITATED SILICON DIOXIDE, METHODS OF ITS PRODUCING AND USE OF THIS SUSPENSION Russian patent published in 1999 - IPC

FIELD: chemical industry. SUBSTANCE: to part of alkaline metal silicate (concentration of SiO₂ is less 20 g/l) an acidifying agent - H₂SO₄ and sodium aluminate (pH 6-7) are added at mass ratio Al/SiO₂ = 1 000:3 300 ppm. Then remained alkaline metal silicate and an acidifying agent are added. Mass ratio of added SiO₂ to SiO₂ in reaction mixture = 10:100. By other variant to alkaline metal silicate before acidification electrolyte is added, precipitated mass is separated, disagglomerated by dilution with water, wet grinding or treatment by ultrasonic oscillation at simultaneous acidification to pH below 4 followed by washing out with an organic solvent, for example, ethanol, ether or their mixture and drying. The content of dry matter in obtained suspension is 10-40 wt.-%, viscosity is 4 x 10^-2 Pa x s, not above, at tangential tension 50 s^-1, content of SiO₂ in floated precipitate after centrifugation for 30 min at 7500 rev/min - above 50 wt.-% of the content of SiO₂ in suspension. Mean diameter of agglomerates D₅₀ - less 5 mcm, agglomeration coefficient Fd - above 3 ml. Invention can be used for making anticorrosive coatings, concrete, paper, mineral glue. EFFECT: improved methods of producing. 21 cl, 4 ex