Fundamental aspects of bubble–particle attachment mechanism in flotation separation

• Bubble–particle attachment mechanism was studied for the DAH–glass system.
• Attachment time could be used to infer flotation response.
• Maximum flotation recovery occurred at isoelectric point of particles and bubbles.
• Hydrophobic force is the driving force of bubble–particle attachment.
• The value of the integrated approach for understanding in research.

Analysis of bubble–particle mechanism is important for improving our understanding of flotation process. The research presented integrates microflotation experiments, bubble–particle attachment time measurements, and colloid and surface characterization and analysis. The bubble–particle attachment time was inversely related to the flotation recovery and the minimum attachment time matched the maximum flotation recovery, which occurred around mutual isoelectric point for the glass particles and air bubbles. Bubble–particle force measurements, performed with an Atomic Force Microscope (AFM), showed a similar trend. Additionally, the adsorption isotherm of the glass–dodecyl amine hydrochloride (DAH) system indicated that there are the three adsorption regions, and the flotation recovery reached its maximum value in the second region of DAH adsorption on the glass surface. All results obtained in this study showed the important role of colloidal forces affected by surfactant adsorption in bubble–particle attachment.

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