Insights into froth phase dynamics: X-ray observations of particle behaviour

Abstract

X-ray radiography presents a non-invasive and dynamic approach for examining multiphase flows, particularly in complex systems like flotation froths. While this technique has been applied successfully in various multiphase studies, such as granular flows and fluidised beds, its utilisation in understanding flotation froths is novel. This study aimed to investigate the behaviour of particles and bubbles within the froth phase using a unique flotation rig combined with an X-ray radiographic setup. Specifically, it sought to understand how the pulp-froth interface influences the entry of bubble clusters into the froth phase and to observe the journey of particles within the froth. The results provided tangible evidence supporting previously inferred phenomena. It was found that the interface between the pulp and froth acted as a barrier, impeding the entry of bubble clusters into the froth phase. However, what was particularly noteworthy about the study was its revelation of extraordinary dynamics in particle movement within the froth phase. These dynamics included the occurrence of reattachment and dropback at critical solid fractions, phenomena that were visually observed for the first time.