An integrated study of bubble-particle attachment mechanisms

This paper presents an integrated approach to studying the attachment interaction between glass particles and air bubbles in the presence of dodecyl amine hydrochloride (DAH). The research presented is novel as it integrates microflotation experiments, bubble-particle attachment time measurements, bubble-particle wetting film stability, and colloid and surface characterisation and analysis. Flotation recovery was found to increase with increasing DAH concentration up to 7 × 10-4 M, and then decrease with further increases in concentration. 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 the point of zero charge for the particle and air bubbles. Bubble-particle force spectroscopy measurements, performed with an atomic force microscope, showed a similar trend. In addition, the adsorption isotherm of the glass-DAH system was obtained. An explanation was given for the reconciliation needed to correlate the contact angle and thin film lifetime results. All results obtained show the important role of liquid films and colloidal forces affected by surfactant adsorption in bubble-particle attachment. Attachment time, as a lumped parameter, is useful for quantifying bubble-particle attachment and for improving our understanding of the flotation process.