Multi-scale analysis of the effect of surfactants on bubble properties. (December 2016)

• Record Type: Journal Article
• Authors: Jávor, Z.; Schreithofer, N.; Heiskanen, K.
• Is Part Of: Minerals engineering. Volume 99(2016)
• Page Start: 170
• Page End: 178
• Publication Date: 2016-12
• Subjects: Flotation frother -- Turbulent condition -- Sauter mean diameter -- Bubble coalescence -- Bubble breakup -- Dynamic surface activity; Mines and mineral resources -- Periodicals; Ressources minérales -- Périodiques; Mines and mineral resources; Periodicals; Electronic journals; 622
• DOI: 10.1016/j.mineng.2016.09.026
• Languages: English
• ISSNs: 0892-6875

Abstract

Graphical abstract: Highlights: Surfactant effect on bubble size in turbulent condition was investigated. Effect of surface-active molecules on bubble size was studied in three size-scales. Characteristic lengths of the three size-scales: >10 −5 m, 10 −5 to 10 −2 m and >10 −2 m. The distinct effect of alcohols and polyglycols was observed in each size-scale. Type of adsorbed molecules influences D32 during bubble formation. Abstract: The effect of surfactants on bubble properties was examined in turbulent conditions. A multi-scale analysis was accomplished with the primary aim to identify the relationship between the size-scale determined surface properties leading to the decrease in bubble size. The adsorption of the surfactants triggers chain reactions acting along different size-scales: it diminishes the tension at the air-liquid interface and increases its surface elasticity (micro/nano-scale; 10 −10 to 10 −5 m) leading to modified coalescence and breakup properties and lower bubble rise velocity (meso-scale; 10 −5 to 10 −2 m) that finally result a smaller bubble size (macro-scale; >10 −2 m). The weakly surface-active DF200 and Pentanol cause a different change in the dynamic properties of the air-liquid interface compared to the strongly surface-active DF250 and PPG leading to differences in size-scale properties and eventually in bubble size. The main result of this work is a comprehensive picture of the dynamics of surface-active molecules affecting bubble size in the presence of random momentum transfer.