摘要：采用分步沉淀法,以自制含硅溶液与氨水反应制备高纯SiO₂粉体,分析溶液pH、氨水浓度及酸洗工艺对SiO₂粉体纯度的影响。结果表明:除去含硅溶液在pH为7时的沉淀物后,继续与氨水反应的沉淀物经过酸洗,可得到常规金属杂质质量分数仅为1.8×10^-6的超高纯纳米SiO2粉体。

关键词：高纯SiO₂粉体；沉淀法；氟硅酸

Abstract： Self-made fluorosilicic acid and ammonia were used to prepare high purity SiO₂ powders by the method of substep precipitation. The effect of pH of the solution， concentration of ammonia and pickling conditions on the purity of SiO₂ powders was investigated. The results indicate that after leaching the precipitation in the fluorosilicic acid solution with pH value of 7， the high purity SiO₂ nano-powders containing regular metal impurity with the mass fraction of only 1.8×10^-6 can be obtained by acid pickling of the precipitation continuously reacting with the ammonia. 

Keywords: high purity silica powders； precipitation method； fluorosilicic acid