FROTHER EFFECTS ON BUBBLE-SIZE ESTIMATION IN A FLOTATION COLUMN

A new method is described in this study to estimate the average bubble size in flotation columns, based on the bubble flow characterization in gas-liquid systems. It was found that if other operating conditions are fixed, higher gas holdups in the column do not necessarily mean that smaller bubbles are produced when comparing with the different frothers used, due to the contamination factor effect on bubbles. Unlike in single bubble systems, the surface tension of the solution cannot be used as a criterion to predict the average size of bubbles produced in the column in the presence of different frothers. Comparisons with photographically measured mean bubble size and literature data were made to confirm the feasibility of the proposed method. The effects of superficial gas and liquid velocities, as well as frother type and concentration on bubble size are discussed.