New insights into the role of nearby particles in bubble-particle detachment

Abstract

Bubble-particle detachment is a crucial factor influencing the upper size limit of flotation and has gained significant attention in recent years. While the detachment of individual particles has been extensively studied, the impact of nearby particles attached to the bubble on the detachment of the central particle remains unclear. Therefore, this study aims to investigate the role of nearby particles in bubble-particle detachment. First, a custom-designed channel flow system was utilized to generate a confined vortex, assessing the stability of bubble-particle aggregates in the presence and absence of nearby particles. Subsequently, the effect of the number of nearby particles on the stability of bubble-particle aggregates was further explored through critical detachment amplitude and detachment force tests. Finally, the role of nearby particles in the bubble-particle detachment was revealed by comparing the three-phase contact line and contact angle changes in the detachment process of the bubble from the glass plate in these two scenarios. The results demonstrate that the presence of nearby particles enhances the critical detachment amplitude and detachment force of the central particle, thereby prolonging the motion time of the bubble-particle aggregates within a confined vortex. This enhancement can be attributed to the alteration of the gas-liquid interface shape near the central particle induced by the nearby particles, which strengthens the pinning effect of the contact line and increases the advancing contact angle. Thus, nearby particles enhance the stability of the aggregates by increasing the capillary force between the bubble and the central particle.