The ion exchange process for silica sol was developed by NALCO in the 1940s and further refined by DuPont and other companies in the 1950s and 60s, becoming the most mature and widely used process.
This process has specific requirements for materials such as water glass and ion exchange resin, as well as for operational procedures, which are precisely the weaknesses of domestic products. In comparison, the one-step hydrolysis method for silica powder is simpler and widely used in China. However, silica sol prepared by this method typically has a particle size of around 10-20 nanometers, with unclear interparticle interfaces, non-spherical morphology that is difficult to control, and unclear interparticle interfaces. Therefore, it is usually only widely used in industries such as casting, and has not made significant progress in more demanding fields such as precision polishing and catalysts.
Compared with internationally renowned silica sol brands, the main disadvantages of domestically produced silica sol include high impurity content, lack of strict control over particle size, lack of rigorous testing of particle specific surface area, low silica concentration, poor stability under acidic or neutral conditions, short service life, some degree of color, and limited variety. Internationally renowned silica sol brands include DuPont and Grace's LUDOX series.