Investigation of the bubble-bubble and bubble-particle interactions in oily bubble flotation system

Flotation, one of the most common beneficiation methods in the mining industry, works efficiently in a narrow particle size range of 20-200 μm. The flotation efficiency of particles below and above this range decreases significantly due to the separation mechanism of the flotation process, which is based on the principle that hydrophobic mineral particles float by attaching to air bubbles. Although various methods and devices have been tried to separate these particles, the problem has not been fully solved. In this context, the aim of this thesis is to increase the floatation of the quartz mineral, which is found as gangue in many ores, at different particle sizes, including below and above the safe flotation size, by using oily bubbles, and also to reveal the bubble-particle attachment time (BPAT) and bubble coalescence time (BCT) in the presence of oily bubbles. For this purpose, BPAT and BCT measurements were carried out in addition to micro-flotation experiments in the presence of conventional air bubbles and oily bubbles. In the experimental studies, dodecylamine hydrochloride (DAH) was used as a collector and methyl isobutyl carbinol (MIBC) was used as a frother. Oily bubbles were created using kerosene-water emulsion. The results obtained from this study showed that agglomeration flotattion and reactive oily bubble flotation are not suitable for the quartz-DAH flotation system, however promising results can be achieved in the presence of oily bubbles. The optimum kerosene concentration in oil bubble production was found to be approximately 100 ppm. The study also revealed that quartz particles attach to oily bubbles much faster than conventional bubbles in the presence of DAH. These results showed that while DAH and MIBC act as inhibitors of bubble coalescence by reducing the air/liquid interfacial tension, kerosene causes bubbles to coalesce in shorter periods of time because it increases bubble hydrophobicity. However, the final effect in the presence of different reagents is controlled by their concentrations.