POLYSILICATE MICROGELS AND SILICON DIOXIDE-BASED MATERIALS Russian patent published in 2002 - IPC

FIELD: inorganic materials technology. SUBSTANCE: polysilicate microgels are prepared by a method involving bringing into contact (i) particles of AB salts with aqueous silicate or polysilicate solution and (ii) A ion with B ion in presence of aqueous silicate or polysilicate solution resulting in precipitation of AB in aqueous phase or (iii) A ion with B ion in presence of aqueous silicate or polysilicate solution resulting in that A and B ions are ions of precipitating AB salt having pK_s value at least 4 measured at 20 C in water. Aqueous silicate or polysilicate solutions contain A ion, which is calcium or magnesium and wherein molar ratio SiO₂:A is less than 2000:1 and more than 1:1, or B ion, which carbonate, sulfate, or phosphate and wherein molar ratio SiO₂:B is less than 2000:1 and more than 1:1. Invention also relates to manufacture of paper involving addition of cationic or amphoteric organic polymer and fine-powder material, namely aqueous polysilicate microgels, to suspension of cellulose fibers followed by formation and dehydration of suspension on screen. EFFECT: simplified procedure and increased silicate and polysilicate concentrations. 24 cl, 1 tbl, 4 ex