Micro-CT imaging of bubble clusters: Extending single mineral observations to a real ore system

In a fluidized-bed flotation system, hydrophobic particles are often buoyed in the pulp phase as bubble clusters. However, the impact of these clusters on the flotation process is not thoroughly understood due to a lack of characterization techniques to study their properties. A technique for studying the properties of clusters using micro-computed tomography (micro-CT) was established with single mineral particles ( Anzoom et al., 2024 ). This study aims to extend this approach to real ores, such as copper ore, where the particles consist of different minerals, to gain a more comprehensive understanding of the properties of bubble clusters. The approach integrates micro-CT, X-ray, diffraction (XRD) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS) to perform three-dimensional quantitative characterization of bubble clusters and visualize the internal structure and distribution of different mineral phases present in the particles. Two methods were used to generate clusters: one involving a hand-shaking experiment and another using a fluidised-bed flotation system. Results revealed that cluster characteristics vary depending on their formation method and the particle size distribution. Particle-particle aggregation was more pronounced in the cluster formed using the hand-shaking experiment. The hydrophobic chalcopyrite mineral phase was observed attaching to bubbles, while gangue minerals were engulfed within particles transported by the bubble clusters. While this study focuses on copper ore, which contains a high concentration of chalcopyrite, the method is applicable to studying bubble clusters with any mineral particles.