(444h) Comparison of the Rise Dynamics of Standard Bubbles and Oil-Coated Bubbles: Experiments and Simulations

Ordinary air bubbles are routinely used in froth flotation, a highly efficient separation method utilized in many industrial processes; and the rise dynamics of standard air bubbles has also been extensively studied for many years. There is also an emerging interest in replacing the standard bubbles with oil-coated bubbles to separate hydrophilic particles with low affinity for the air-water interface, but the rise behavior of oil-coated bubbles has not been well explored yet. In our work, we systematically investigated the shape, velocity and trajectory of bubbles engulfed in a layer of oil, and experimental results were compared to computer simulations to confirm a pronounced effect of the oil coat on the bubble dynamics. We consistently found that oil-coated bubbles display a more spherical shape, lower rise velocity and straighter trajectory than the standard air bubbles, which can benefit the flotation process.