The growing demand for nonrenewable mineral resources and the exhausting of high grade deposits forced the mineral industry to cope with the challenge of processing ores of increasing complexity aiming at producing concentrates meeting specifications that become continuously more strict. Under this scenario, innovative pieces of equipment and techniques for the concentration of ores have been developed in the past years. Among these developments, column flotation proved to be a proper technique for processing low grade ores, presenting a high liberation degree only at fine size ranges. The performance of a flotation column is closely related to the size and distribution uniformity of the air bubbles introduced at its bottom. Consequently several types of sparging systems are available in the world market. This investigation was performed aiming at comparing two types of spargers that are presently utilized in Brazilian concentrators: the standard air/water sparger system and the single nozzle (at the end) sparger, utilizing air only. The results indicated that, under the usual operation conditions of flotation columns, the water/air sparger generates bubbles with smaller mean diameters than those achieved with the air only sparger. The water/air sparger is recommended in industrial applications requiring small bubbles, uniform in size, for enhanced metallurgical performance.
column flotation; industrial spargers; bubble size
