粉石英制备高纯球形纳米SiO_2

Preparation of High-purity Spherical Nano-SiO_2 from Powder Quartz

以价格低廉天然优质粉石英矿物为基本原料,采用改进溶胶-凝胶技术,盐酸和硅酸钠溶液共滴加的方式,制备高纯球形纳米SiO2粉体材料。研究了体系中硅酸钠浓度及纯度、pH值、表面活性剂及分散剂等因素对其性能的影响。制备出的高纯纳米SiO2粉体中SiO299.97%、Al3+9×10-6、Fe3+1.04 9×10-6、Na+≤3.59×10-6、Cl-≤19×10-6,平均粒径在50～80 nm。研究结果表明:制备的SiO2粉体为高纯、球形、分散度高且粒度均匀,能达到电子封装材料功能填料用高纯球形纳米二氧化硅性能指标要求。本文重点探讨原材料对其纯度的影响,团聚机理及解决团聚的措施。该方法具有成本低及易于工业化的特点。

High-purity spherical nano-SiO2 powder was prepared from low-price high-quality powder quartz by sol-gel method and the way of simultaneous addition of hydrochloric acid and sodium silicate solutions.The effects of concentration and purity of sodium silicate,the dosage of ammonia,pH,surfactant and dispersing agent on the performance of nano-SiO2 powder were investigated.The purity of SiO2 powder was analyzed and the nano-SiO2 was also characterized by XRF,XRD and SEM.The chemical composition of the nano-SiO2 powder was：99.97wt%SiO2,9×10-6Al3＋,no more than1.04×10-6 Fe3＋,no more than 3.5×10-6 Na＋,no more than 1×10-6 Cl-and no more than 1×10-6SO42-.The results of the study show that the nano-SiO2 which was prepared in this study was highly pure spherical,highly dispersed and uniform in particle size.The performance of nano-SiO2 can satisfy the requirement of functional filler of electronic packaging materials.This paper was focused on the influence of the purity of raw material on the purity of nanometer SiO2,the mechanism and method of aggregation reduction.