Abstract: A method for producing a micron-size spherical silica aerogel having a selectable or controllable average particle size, the method includes producing a surface-modified silica sol by adding a first organosilane compound to a aqueous acid-silica sol, which comprises an inorganic acid and a water glass solution, with a pH less than 3, dispersive mixing a non-polar organic solvent, a second organosilane compound, and the surface-modified silica sol, at a selected stilling rate which is inversely related to an average particle size, without adding any surfactant or dispersant, a micron-size spherical silica hydrogel and further a hydrophobic micron-size spherical silica gel are then produced. Following by drying or stirring the hydrophobic micron-size spherical silica gel to obtain a controllable micron-size silica aerogel in a spherical and powder forms, respectively.

Abstract: A method for producing a micron-size spherical silica aerogel having a selectable or controllable average particle size, the method includes producing a surface-modified silica sol by adding a first organosilane compound to a aqueous acid-silica sol, which comprises an inorganic acid and a water glass solution, with a pH less than 3, dispersive mixing a non-polar organic solvent, a second organosilane compound, and the surface-modified silica sol, at a selected stilling rate which is inversely related to an average particle size, without adding any surfactant or dispersant, a micron-size spherical silica hydrogel and further a hydrophobic micron-size spherical silica gel are then produced. Following by drying or stirring the hydrophobic micron-size spherical silica gel to obtain a controllable micron-size silica aero-gel in a spherical and powder forms, respectively.