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 mea surement of bubble size distributions in flotation cells containing sl urries of high solids concentration. The device separates bubbles from a slurry into a water solution where they may be measured using a bub ble size analyser. An experimental programme of measuring bubble sizes in two and three-phases is reported in which the bubble sampler was e valuated and the effect of different frothers on the bubble size distr ibution in two and three-phases was investigated. In two-phase operati on (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/g as) system,the mean bubble size was found to increase, and only the fu rther addition of frother could reduce it to its former value. Differe nt frothers were found to have very different effects on the size of b ubbles produced in slurries compared with those produced in two-phase systems. Of the frothers tested MIBC was found to be the best all roun d performer in terms of bubble size reduction with increasing solids c oncentration.