| 摘要 |
The invention relates to the production of fine precipitated silicium dioxide having a significant pore volume and high water and oil absorbing ability which is used in the form of a filler for various materials such as elastomers, rubbers, tooth pastes, varnishes, paints and absorbers for column chromatography, removing oil spots etc. The inventive method for producing fine highly porous silicium dioxide consists in adding a solution of sodium or potassium silicate with a concentration of SiO2 ranging from 3 to 35 in relation to a sulphate solution, or carbonate, or bicarbonate, or chloride, or ammonia nitrate, or ammonium format or acetate with concentration ranging from 5 to 40 mass% at a ratio between the total quantity of SiO2 added with silicate and to the quantity of ammonia salt equal to or less than 2 associated with the precipitation of a hydrogel suspension at a temperature of 35-39 DEG C. The thus precipitated silicium dioxide hydrogel is reprocessed by a solution of sulphate, or carbonate, or bicarbonate, or chloride, or ammonium nitrate, or ammonium format or acetate with concentration of 5-15 mass%. The novelty of the invention lies in that a precipitation rate is set up higher than 300g of SiO2/l of suspension per hour, excluding areas of local oversaturation of a reaction mixture when potassium silicate is supplied in a reaction zone. |
