Abstract: In order to study the mechanism of particle-bubble separation and stability in coal slime flotation, a self-designed flotation particle bubble adhesion and detachment behavior test system was used to investigate the detachment behavior between long flame coal with three different shapes (long strip, triangular cone, sphere) and the surface of bubble. The stability of the particle-bubble was evaluated by the critical detachment amplitude, and the experimental phenomena were explained from the perspective of force balance. The results show that the spherical particles are more easily detached from the bubbles than the irregularly shaped elongated and triangular pyramidal particles.The detachment behavior is closely related to adhesion patterns. When the long side of the particle is in contact with the bubble, the three-phase contact line is long, the capillary force is large, and bubble-particle is stable, so a larger critical detachment amplitude is required. When the short side of the particle is in contact with the bubble, the three-phase contact line is short, the capillary force is small, bubble-particle is unstable, and the critical detachment amplitude is small. This conclusion provides theoretical basis for reducing particle-bubble detachment probability in coal flotation.