Energy mechanism of detachment between particle and bubble

The stability analysis between particles and bubbles is the focus of research in the field of flotation. The traditional detachment theory holds that the particle detachment from the surface of the bubble when the external force on the particles is greater than the maximum adhesion force between the particles and bubbles. The dynamic process of the sliding shrinkage of the gasliquidsolid threephase contact line is ignored,and the effect of duration of detachment force on the detachment process is not considered. In order to improve the theory of particlebubble detachment in flotation,the critical detachment force and detachment energy of the particlebubble detachment process were measured by using an adhesion force tester,taking single particle and single bubble as research objects. Then the particlebubble vibration detachment observation system was used to observe the sliding shrinkage of threephase contact line during the detachment process. Finally,a new method for evaluating the stability between particles and bubbles based on energy analysis is proposed from the perspective of thermodynamics. The results show that the stability between particles and bubbles increases with the increase of particle contact angle,and the critical detachment force and detachment energy for detachment increase. The detachment energy between particle and bubble is composed of two parts:the deformation energy in the tensile deformation stage of bubbles and the sliding energy in the sliding contraction stage of the threephase contact perimeter,both of which increase with the increase of the particle contact angle. The detachment of particles from the surface of bubbles requires that the external force is greater than the maximum adhesion force between particles and bubbles,and on the other hand,sufficient time of the external force is required to complete the sliding contraction in the threephase contact line. From the perspective of energy,the particles and bubbles can be regarded as a thermodynamic system in equilibrium when there is no external force. When the work done by the external force is less than the detachment energy,the particles and bubbles remain stable through the changes in the interface area of gasliquid,liquidsolid and gassolid. However,when the work done by the external force is greater than the detachment energy,the particles and bubbles are completely separated.