Single bubble behaviour study in a flotation column /

The axial velocity profiles (local velocity versus time or position) of single bubbles in the absence and presence of flotation reagents such as frother were measuredin a water-jacketed transparent Plexiglas square (10 x 10 cm) column over a distance of 400 cm. The test liquid temperature was maintained uniform and constant at 30 °Cby water circulation in the jacket. Single bubbles, covering a size range of interest in flotation, were studied. A bubble generation frequency was selected such that velocitywas independent of frequency. To follow the bubble during its rise, a video camera supported on a track and capable of moving vertically at adjustable speeds was employed.Dans une colonne de flottation carree (10 x 10 cm) a chemise d'eau faite de plexiglas transparent, on a mesurd, sur une distance de 400 cm, les profils de velocite axiale (velocite locale versus temps ou position) de bulles simples avec ou sans la presence de reactifs de flottation tel le moussant. En circulant de l'eau dans la chemise, la temperature du liquide a l'interieur de la colonne fut maintenue a une temperature constante de 30°C. On a etudie des bulles simples ayant des diametres d'intdret pour la flottation. Une frequence de Ondration des bulles fut choisie afm que la velocite soit independante de la frequence. Pour suivre la bulle lors de son ascension, on a utilisë une camera video montee sur rail et pouvant se placer verticalement a des vitesses variables. f