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4729662 
Journal Article 
Effect of surface electrical charge on microbubbles' terminal velocity and gas holdup 
Perez-Garibay, R; Bueno-Tokunaga, A; Estrada-Ruiz, RH; Camacho-Ortegon, LF 
2018 
1 
Minerals Engineering
ISSN: 0892-6875 
119 
166-172 
WOS:000428006200021 
The objective of this research was to study the effect of the electrical charge of microbubbles on their terminal velocity when they are conditioned with typical flotation reagents. Some of the contrasting collectors studied were potassium ethyl xanthate (anionic) and dodecylamine (cationic), and the studied frothers were terpinol, methyl-isobutyl-carbinol (MIBC), and 2-ethylhexanol. It was found that the microbubbles' terminal velocity is mainly affected by their diameter, but the electrical charge has a significant effect, as it can change the boundary layer thickness of water surrounding each bubble. This behaviour is explained by considering that the attraction between the potential-determining ions and the counterions [e.g., hydrated proton ( +) and xanthate ()] shrinks and compacts the boundary layer thickness, which can reach high density, decreasing the microbubble terminal velocity. The opposite occurs when the bubble charge has the same sign as the counterions [e.g., hydroxyls () and xanthate ()]; in this case, the diffuse layer and the boundary layer do not grow and the bubble terminal velocity increases. 
Microbubbles; Terminal velocity; Double layer charge; The boundary layer thickness