| 摘要 |
In a process for preparing finely-divided SiO2 by heating quartz sand and carbon to at least 1400 DEG C. and subsequently burning the SiO formed in air to SiO2, a polyvalent metal which will reduce SiO2 is added to the starting mixture in an amount from 0.02-0.2 mol per mol SiO2. The metal may be powdered Mg, Ti, Zr, Ca, or Al, and the mol ratio SiO2:C and metal may be 1:1 to 1.2, preferably the ratio SiO2:C:metal is 1:1.05:0.05. The mixture is heated to 1400-2000 DEG C. in an inert atmosphere e.g. A or CO. |
