Investigation of bubble-particle attachment, detachment and collection efficiencies in a mechanical flotation cell

• Published in: Powder technology Vol. 375; pp. 109 - 123
• Main Authors: Darabi, Hossna, Koleini, S.M. Javad, Deglon, David, Rezai, Bahram, Abdollahy, Mahmoud
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 20.09.2020; Elsevier BV
• Subjects: Attachment; Bubble-particle attachment efficiency; Bubble-particle collection efficiency; Bubble-particle detachment efficiency; Bubbles; Collection; Efficiency; Energy dissipation; Flotation; Impellers; Mechanical flotation; Particle image velocimetry; Turbulence; Velocity; Turbulence; Mechanical flotation; Bubble-particle attachment efficiency; Bubble-particle detachment efficiency; Bubble-particle collection efficiency
• ISSN: 0032-5910; 1873-328X
• DOI: 10.1016/j.powtec.2020.07.085

The paper presents the effect of impeller speed and superficial gas velocity on bubble-particle attachment, detachment and collection efficiencies using pure quartz particles in a mechanical flotation cell. Detachment and collection efficiencies in different parts of cell were calculated by local turbulent energy dissipation rate measurements using high speed stereoscopic particle image velocimetry technique. In addition to high detachment efficiency, low attachment efficiency is also one of the reasons for low collection efficiency for coarse particles. The flotation rate constant increased with an increase in superficial gas velocity. However, the effect of superficial gas velocity on collection efficiency was negligible. This means that any effect of superficial gas velocity on flotation rate constant was due to changes in the number of bubbles and collision frequency. The flotation rate constant, collision frequency, and the number of bubbles increased with increasing impeller speed. However, collection efficiency decreased with increasing impeller speed. [Display omitted] •The effect of N, Jg and dp on Ea, Ed, E and k were investigated.•Ed and E in different parts of cell were investigated.•In addition to high Ed, Ea has a significant role in low E of coarse particles.•The impeller zone had significant effect on the bubble-particle interactions.•Any effect of Jg and N on the k were due to the associated changes in Nb and Zpb.