Effect of fine solids and frother on gas hold-up and liquid mixing in a flotation column

The effect of fine solids and frother addition on gas hold-up and average bubble rise velocity in bubble swarm, and liquid phase mixing intensity has been studied in a 0.06 m flotation column. The variables studied were frother (pine oil) addition, feed solid concentration, gas and slurry velocities. The gas hold-up was estimated from the static pressure method, while the liquid phase mixing intensities were estimated using the pulse technique. In comparison with our previous air-water study [1], frother addition has a drastic effect on bubble characteristics, while the effect of solids is negligible except at low gas velocities for which complete suspension of solids from the gas distributor were not observed. The presence of small quantities of solids on the gas distributor resulted in bubble coalescence even in the presence of frother. In general, frother addition resulted in an increase in the liquid mixing intensity while the presence of solids had the opposite effect. Our results indicate that in the presence of frother, the bubbly flow regime is maintained over a wider gas velocity range.