Method for manufacturing silica sol

A method for manufacturing a silica sol, the method comprising:

• preparing a silica sol reaction liquid by hydrolyzing and polycondensing an alkoxysilane or a condensate thereof using an alkali catalyst in a solvent;
• and
• at least one of:
• concentrating the silica sol reaction liquid by an ultrasonic atomization separation method;
• or
• replacing the silica sol reaction liquid with water by the ultrasonic atomization separation method,
• wherein the ultrasonic atomization separation method comprises:
• continuously supplying the silica sol reaction liquid to an ultrasonic atomization chamber from a reaction liquid tank,
• irradiating the silica sol reaction liquid is with ultrasonic waves upward from a bottom of the ultrasonic atomization chamber toward a liquid surface of the silica sol reaction liquid to generate a mist from the liquid surface of the silica sol reaction liquid;
• introducing a carrier gas into the ultrasonic atomization chamber to transfer the mist of the silica sol reaction liquid atomized in the ultrasonic atomization chamber into a separator, wherein the separator is a cyclone;
• and
• subjecting the mist to centrifugal force in the cyclone, wherein the mist is separated based on the mass of the mist, and wherein mist having a large particle size comprising water and a very small amount of silica particles moves to an inner surface of the cyclone and is discharged from a lower outlet and supplied to a reaction tank, and mist comprising the solvent and the alkali catalyst discharges from an upper outlet.