Effect of cationic collector on the attachment of glass beads to a stationary bubble

Abstract Glass beads in contact with a stationary air bubble immersed in dodecylamine hydrochloride (DAH) collector solution were investigated to examine the effects of a cationic collector on bubble–particle attachment. A high-speed video camera was used to record images of bubble–particle interactions. When the bubble diameter was 1.05–1.9 mm, the induction time initially decreased then increased as the bubble size increased in a 10−5 mol/L DAH solution. Experiments demonstrated that the induction time increased as the collision angle increased. However, in solutions with higher DAH concentrations, the distribution of induction time was scattered, and the jump-in events were observed above the horizontal equator of the bubble; particle aggregation was also observed. When the DAH concentration increased from 10−5 to 10−3 mol/L, the induction time initially increased and then decreased. Analysis of the attachment for large numbers of particles verified that the correlation between induction time and attachment efficiency was stronger than the correlation between contact angle and attachment efficiency. At the solution concentration for which the induction time was maximum, the particle attachment efficiency was the lowest. The effects of the collector on bubble–particle attachment were examined in multi–perspectives. This study introduces new insights into the bubble–particle attachment and offers an increased, more comprehensive understanding of the attachment mechanisms.