| Title | Silica Powders Production from Hydrothermal Solutions |
|---|---|
| Authors | Potapov V.V., Gorbach V.A., Tatarinov S.A., Portnyaguin V.N., Kashutina I.A. |
| Year | 2011 |
| Conference | Stanford Geothermal Workshop |
| Keywords | hydrothermal solution, silica sol, membrane concentration, cryochemical vacuum-sublimation drying, silica nanopowders |
| Abstract | Obtaining of nanodispersed silica powders from natural hydrothermal solutions is described. Hydrothermal solutions contain the colloid silica forming as a result of polycondensation of the molecules of orthosilicic acid. Via ultrafiltration membrane concentration of hydrothermal solutions, silica sols with SiO2 contents up to 940 g/dm3 (62.2 wt %) and particle radii of 29--135 nm are obtained. The silica powders with the specific surface of 110--400 m2/g, average pore diameter of 3--10 nm, and pore volume of 0.2--0.3 cm3/g are obtained via cryochemical vacuum-sublimation drying of sols with the use of liquid nitrogen. The particle size in the powders is in the range from 10 to 100 nm. |