The present work compares the flotation recoveries of silica at different particle sizes with oscillatory air supply and conventional steady air supply. The flotation tests were carried out at continuous mode using a 50 mm diameter column equipped with a sparger. Bubble size and gas holdup were measured in the presence and absence of silica particles. The results showed that converting steady air supply to oscillatory air supply could lead to significant improvement of flotation recovery at all particle size fractions tested in the present work, including a 54% increase in flotation recovery for ultrafine particles (-10 pm) and an extension of the upper limit of particle size. The improvement of flotation recovery was linked to decreased bubble size and increased gas holdup. The present study has important implications for research on fine and coarse particle flotation.