Abstract: The kinetics of particle-bubble detachment was studied by a high-speed dynamic test system. The Image-Pro Plus was used to measure the contact angle and three-phase contact perimeter of particle-bubbles， and to calculate the change of capillary attachment force between particles and bubbles with the movement time of particles. The results show that the detachment of particles from the surface of bubbles is mainly divided into two stages: the contact angle of bubble stretching deformation increases and the three-phase contact perimeter decreases. In the bubble stretching stage， the three-phase contact perimeter is fixed on the particle surface， and the contact angle increases from equilibrium contact angle to advancing contact angle. In the bubble sliding stage， the contact angle remains unchanged， while the three-phase contact perimeter sliding decreases. In the process of bubble detachment， the capillary attachment force increases with the increase of the contact angle and decreases with the sliding of the three-phase contact perimeter. When the external force exceeds the capillary attachment force between particles and bubbles， the particles detachment from the bubble surface.

Key words: Flotation, Particle-bubble, Detachment, High-speed dynamic camera, Capillary attachment force