BUBBLE SIZE DISTRIBUTION MEASUREMENTS IN A POROUS MEDIA-AERATED FLOTATION CELL

Bubble size distribution in a porous media-aerated flotation cell was investigated by using an image analysis technology in this paper. Results showed that it was feasible to determine the bubble size distribution according to image analysis software. For a porous media-aerated flotation cell, bubble size was directly dependent on poles size of porous media. Furthermore, operating parameters of the cell could affect bubble size. Mean bubble diameters increased with increasing of air flow rate. In contrast, it decreased when adding deinking agent. Its decreasing with increasing pulp flow rate under given conditions illustrated the fact that proper turbulence strength at the inlet of air bubbles was favorable for reducing bubble size. Gas holdup increased with increasing air flow rate to some extent, but it had a peak value. Gas holdup would rise obviously when deinking agent existed in the cell. An efficient approach to enhancing bubble surface area flux was to increase air flow rate and keep small bubble size at the same time.