Preparation method of colloidal silicon dioxide

The invention relates to a preparation method of colloidal silicon dioxide.According to the preparation method,a method that colloidal silicon dioxide particles grow while being filtered and ultra-filtered, concentrated and drained, so that the manufacturing period of the particles is shortened by more than half, and the production efficiency is greatly improved; the particle size of the prepared colloidal silicon dioxide is 60-150 nm, the number of large particles (particles larger than or equal to 0.56 micrometer) is smaller than 1 million particles/ml, scratches generated in the polishing process can be effectively reduced, and the colloidal silicon dioxide can be used for various polishing solutions. 本发明涉及一种胶体二氧化硅的制备方法，本发明采用胶体二氧化硅颗粒边生长边过滤边超滤浓缩排水的方法，实现颗粒制造周期缩短一半以上，生产效率大大提高；制备得到的胶体二氧化硅，粒径在60nm-150nm，大颗粒数(≥0.56微米的颗粒数)