Microbubble generation with shear flow on large-area membrane for fine particle flotation

Abstract

Fine particle flotation is carried out in a flotation column with a 19-channel ceramic membrane sparger. The microbubble generation is controlled by the shear flow in the membrane channels. Bubbles in the flotation column are photographed via a high speed video camera. Gas holdup and quartz recovery is investigated under different operating conditions. Gas holdup in the flotation column firstly increases and then decreases with the increase in superficial gas velocity. Similar trend in gas holdup is also found by increasing cross flow velocity. Larger particle concentration in the feed results in smaller gas holdup, while the gas holdup positively changes with collector concentration. The quartz recovery is strongly influenced by gas holdup and bubble size. Similarly, the recovery firstly increases and then decreases when increasing superficial gas velocity and cross flow velocity. The collector concentration plays a more obvious role in flotation recovery at high superficial gas velocity.