Abstract
To develop a simple technique for separating submicron particles, aqueous suspensions of silica
particle mixtures were ultrasonically atomized and the behavior of particle separation was examined under
various conditions.
Ultrasonic atomization brought silica particles of a specific size, 100 nm into fog from a suspension containing
a mixture of silica particle of 100 and 300 nm. Most of the fog was successfully recovered with liquid nitrogen
coldtrap, and the recovery percent of particles reached more than 90 %. In the recovered suspension,
enrichment of 100 nm particle was observed and dilution of 300 nm was attained. The result indicated
selective transfer of 100 nm silica particle into the fog and rejection of 300 nm silica particle. Interestingly, the
separation disappeared after degassing the feedstock. Also, when the gas dissolving in the suspension was
changed from air to argon, the rejection of 300 nm silica particle was decreased. The separation, selective
transfer of silica particle depending on the size was significantly affected by the amount of dissolving gas as
well as type of the gas. The result clearly indicates a strong influence of cavitation on the separation
mechanism.
