Experimental Study and Visualization of Particle/Bubble Collision in the Presence of Fluid

Flotation is the most important method for the separation of minerals. A key element of recovering valuable minerals through flotation is particles/air bubbles interaction in water. In the present paper, an experimental approach is proposed to study the collision of fixed bubble and particles. The results of this investigation are widely used in the application of plastic particle flotation. In this paper, by creating a bubble with a diameter of 5.5 mm through injection pump in fixed fluid, the plastic particles (with a diameter of 1.5 mm) are released on the surface of the bubble. The polar position of the particles on the bubble surface is changed by variations of the falling height and increasing the height of release leads to a decrease in the polar position of collision on the surface of the bubble. The initial collision angles at the release heights of 18.68mm, 13.36mm, and 10mm are 18.01, 15.15, and 18.8 degrees, respectively. In this study, the effect of forces of drag, capillary, pressure, weight, and buoyancy on the attachment and detachment of the particle on the surface of the bubble has been reported. Due to the low sliding velocity of the particle on the surface of the bubble, the drag force is negligible at the attachment and detachment case and floating and gravity forces are also constant. The main roles in effective forces of collapse are capillary and pressure forces. The effect of the three-phase contact line on the capillary and pressure forces is also analyzed, which is one of the innovations of the present study.