| 摘要 |
PURPOSE: A method for preparing ultra-fine silica powder with a mean particle size of 0.1 to 2 μm by the reaction of sodium silicate with fluosilicic acid (H2SiF6) is provided. CONSTITUTION: The ultra-fine silica powder is fabricated by slowly dropping 5 to 35 wt.% of sodium silicate to 1 to 25 wt.% of fluosilicic acid (H2SiF6) under agitation at about 70 deg.C until hydrogen-ion concentration comes to pH 4.5 to 10.5 to form precipitate. Further, a surfactant with an HLB value of 3 to 10 is additionally added in an amount of 0.01 to 0.2 wt.% based on the 100 wt.% of sodium silicate. Furthermore, hydrocarbons including benzene and hexane are additionally added.
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