沉淀法微细二氧化硅的制备

Micron SiO_2 Particles by Precipitation Method

采用水玻璃滴入氯化铵溶液的反滴氯化铵化学沉淀法,以阳离子表面活性剂十二烷基苄基三甲基氯化铵为调控剂合成了微细二氧化硅。采用扫描电子显微镜（SEM）、激光粒度分析仪、X射线衍射（XRD）仪对二氧化硅微粒的形貌、粒度分布和结构进行表征。探索了氯化铵反滴法比普通滴酸法和普通氯化铵法更易生成沉淀的反应机理,研究了十二烷基苄基三甲基氯化铵加入量、陈化p H值以及陈化时间对二氧化硅颗粒形貌和粒度的影响。结果表明,当十二烷基苄基三甲基氯化铵的加入量为二氧化硅理论产量的1.6%,在p H值=2~3的条件下,陈化16 h后得到粒径为5μm左右,原生粒子为纳米级,粒度分布极窄,分散性好的二氧化硅颗粒。

Micron Si O_2 particles was synthesized by ammonium chloride reverse- titration precipitation method,which used cationic surfactant dodecyl benzyl trimethyl ammonium chloride as modulators. Morphology size distribution and structure of Si O_2 paticles was characterized by scanning electron microscopy（ SEM） laser particle size analyze（ Ls- pop） and X- ray diffraction（ XRD）. Micron Si O_2 particles was easier to be synthesized by precipitation use ammonium chloride reverse- titration precipitation method than general precipitation dropping inorganic acid and dropping ammonium chloride. It was investigated The effect of the addition amount of dodecyl benzyl trimethyl ammonium chloride,aging p H and aging time on the morphology and size distribution of Si O_2. The results indicated that the optimum condition of synthesizing micron Si O_2 was as follows the concentration of the mass ratio of dodecyl benzyl trimethyl ammonium chloride to Si O_2 particles was 1. 6%,aging p H was 2- 3 and aging time was 16 h. The micron Si O_2 agglomerated by nanometer primary particles was well dispersed and had similar size,which the average size was 5 μm.