The Preparation, Properties, and Application of Nanosilica Based on Hydrothermal Solutions

Experiments on the preparation of sols and nanopowders of SiO 2 based on hydrothermal solutions are performed. In order to achieve a result, processes of polycondensation of orthosilicic acid, ultrafiltration membrane concentration, and cryochemical vacuum sublimation are performed. The physicochemical characteristics of the sols and nanopowders of SiO 2 are determined using a set of methods. In particular, it is shown that the diameters of the nanoparticles of SiO 2 in the sols and nanopowders fall within the range of 5 to 100 nm. The possibility for the application of the obtained nanosilica as a modifying additive for the enhancement of the strength of concrete is justified.