AN EVALUATION OF A DIRECT METHOD OF BUBBLE-SIZE DISTRIBUTION MEASUREMENT IN A LABORATORY BATCH FLOTATION CELL

In this paper a novel bubble sampler is described which allows the measurement of bubble size distributions in flotation cells containing slurries of high solids concentration. The device separates bubbles from a slurry into a water solution where they may be measured using a bubble size analyser. An experimental programme of measuring bubble sizes in two and three-phases is reported in which the bubble sampler was evaluated and the effect of different frothers on the bubble size distribution in two and three-phases was investigated. In two-phase operation (liquid/gas), the bubble sampler was proved to supply accurate and reproducible measurements when compared with measurements made hy the bubble size analyser without the sampler fitted. The frother type was found to have the greatest influence on bubble size. With the addition of solids (gold plant tailings) to form a three phase (solid/liquid/gas) system,the mean bubble size was found to increase, and only the further addition of frother could reduce it to its former value. Different frothers were found to have very different effects on the size of bubbles produced in slurries compared with those produced in two-phase systems. Of the frothers tested MIBC was found to be the best all round performer in terms of bubble size reduction with increasing solids concentration.