Picobubble enhanced flotation of coarse phosphate particles

A picobubble enhanced flotation column has been developed for enhancing recovery of coarse phosphate particles (-1180 μm + 425 μm) that are very difficult to recover by conventional flotation. Cavitation generated picobubbles are characterized by inherently high probability of collision, high probability of attachment and low probability of detachment from hydrophobic particles due to their tiny size and high surface activity, and therefore are effective for enhancing flotation recovery of coarse phosphate particles. Experimental results indicate that the flotation recovery of coarse phosphate particles of varying floatability was increased by 10 to 30 absolute percentage points. The collector dosage was reduced by one half to two thirds as a result of the selective adsorption of picobubbles on hydrophobic phosphate particle, which act as a secondary collector. The frother dosage was also reduced by more than half since picobubbles are smaller than 1 μm when they are formed from air precipitation.