Gas holdup in flotation columns: laboratory measurements

The gas holdup in laboratory flotation columns was measured using a conduct ivity probe. Measurements in a 50-cm-diameter flotation column have shown t hat gas holdup varies radially depending on the sparging system array, surf actants addition, and spargers malfunctions. The column was run in two mode s: unbaffled (open), and baffled(vertically). Radial differences in gas hol dup are enhanced by using baffles if gas is not uniformly injected through the spargers in the flotation column; however, the gas holdup is the same a mong the quadrants of the baffled column when the gas is evenly injected. D rift flux analysis was applied to estimate bubble size; it was a bubble siz e radial distribution in the column that was consistent with the gas holdup . (C) 2001 Elsevier Science B.V. All rights reserved.