Research progress of relative motion between particles and bubbles in froth flotation

The study of the relative motion between particles and bubbles is critical to the understanding of froth flota-tion mechanism,and has a guiding significance for the development of new flotation machines and the im-provement of flotation efficiency. In this paper,the research progress of relative motion between particles and bubbles was reviewed. In the early research,some researchers ignored the effects of particle and bubble property. Particles were regarded as points moving along the streamline and bubbles were regarded as rigid spheres. Streamline equations were used to study the relative motion. With the continuous research,the effects of physical and chemical properties of particles and bubbles have gradually received extensive attention. Researchers have done a lot of researches on particle inertial force,gravity,shape and roughness,and the mobility of bubbles surface. Particle sedimentation method was used to study the relative motion between particles and bubbles. The research object was developed from a single glass bead to a large number of mineral particles,and the relative motion between the moving glass bead and the rising bubble has been studied. Research shows that the streamline equation is applicable to the study of the relative motion between par-ticles and bubbles when the particle size is fine and the density is small,and the influence of inertial force and gravity on the relative motion should be considered when the particle size is coarse and the density is large. In addition,the ir-regularity of particle shape will affect the force of the liquid around the particle,resulting in the decrease of the critical collision radius,and the irregular surface protrusion will accelerate the rupture of the liquid film between particles and bubbles. Increasing the surface roughness of particles can help to enhance the adhesion strength between particles and bubbles. The “stagnant-cap” model can be used to analyze the bubble surface mobile. Particle sedimentation method is mainly used to study the relative motion between particles and bubbles. The hydrophilic glass beads can only slide in the upper hemisphere of the bubble,and then leave the bubble near the equator of the bubble. The hydrophobic glass beads will pierce the thin liquid film between particle and bubble. After crossing the bubble equator,it will continue to slide along the bubble surface and attach to the bottom of the bubble. The adhesion efficiency of coal particles decrea-ses with the increase of collision angle and coal density. However,the current research focuses on the field of still wa-ter. The relative motion between particles and bubbles in the flotation flow field needs a further investigation.