The use of microwave energy for obtaining dry silica sol

Presented in this work is an original technique of obtaining high-concentration silica sols which are widely used in various branches of industry. This technique consists of three stages: synthesis, stabilization and drying of the silica sols. Microwave evaporation was used at the stage of final drying and removed the local hot spots of the drying substance, thus helping to avoid the formation of a non-reversible gel. The silica sol was dehydrated till 60% concentration and then placed in the chamber of a teflon reactor. The experiment was carried out at one of the industrial frequencies. The uninterrupted mode of generation was used. Silica sol obtained in this way is 100% reversible, e.g. its dry powder disperses in water to a 100% extent, forming an initial colloidal solution.