| 摘要 |
A method for producing precipitated silica products having a unique combination of physical and chemical properties is disclosed. The products are produced by acidulating a solution of an alkali metal silicate with an acid under carefully controlled precipitation conditions. In accordance with the method, at least a portion of the alkali metal silicate solution theoretically required to react with said acid is initially charged to the reaction vessel. Thereafter, the remaining silicate solution and the acid are simultaneously added to the reaction vessel in a manner to control the alkalinity of the reaction medium. By controlling the percent of the silicate solution initially charged to the reaction vessel, silicas having predetermined properties can be obtained. Properties of the products include low wet cake moisture content, low structure, low oil absorption, high abrasivness, and low void volume. The products can be used as abrasive and polishing agents in dentifrice compositions. In one particular advantageous embodiment, an adduct material, such as aluminum, is added to control the refractive index of the product. |
