Investigations of bubble–particle interactions

Abstract

Bubble–particle interaction during flotation comprises of collision, attachment and detachment. This paper presents a review of our investigations into these microprocesses. Analysis of collision phenomenon focuses on the physicochemical hydrodynamics of water flow passing the rising bubbles. The influence of the fore-and-aft asymmetry of water streamlines and of the mobility of the bubble surface on collision efficiency is quantified. In the case of attachment, the analysis considers contact and attachment times and reveals that the available models for contact times are far from satisfactory. It may be necessary to include short-range hydrodynamic interactions for the modeling of contact times. At present, the actual attachment time is difficult to predict from first principles. Finally, the examination of detachment focuses on models for predicting the tenacity of attached particles. The influence of the bubble size on tenacity is also analyzed. Simplified equations describing the maximum particle size for stable attachment to air bubbles are derived.