| 摘要 |
The invention relates to a colloid of silica of spherical form, with a mean particle diameter of between 10 and 100 nm, as well as balls of silica, with a mean diameter of between 50 and 300 nm. Such products may be obtained by the addition of an alkaline silicate and an acidifying agent with the addition of the reactants to an aqueous bottom, at a constant volume, and with the reaction medium being continuously drawn off. The novel products are useful as thickening agents and strengthening fillers. |
