Characteristics of NanoSilica Produced from Hydrothermal Solutions

Resumo

SiO₂ sols and nanopowders are produced from hydrothermal solutions using the following processes: polycondensation of orthosilicic acid, ultrafiltration membrane concentration, and cryochemical vacuum sublimation. The physical–chemical characteristics of SiO₂ sols and nanopowders are determined: particle size distribution, specific surface area, viscosity, and impurity ions content. It is demonstrated that the size of SiO₂ nanoparticles in sols and nanopowders could attain 5–100 nm. The possibility of applying the produced silica to strengthen the concrete is justified.