Applying particle-based separation modelling on 3D particle data to better quantify the influence of particle size and shape in the recovery of valuable elements

After the successful application of 2D particle characterisation in the raw materials sector, the transition to 3D particle characterisation methods holds the potential of further improving the efficiency of the sector. The main reason to characterise particles in 3D is to obtain reliable information about their shape and size. Yet, given the complexity of particles in the raw materials field, particle composition should be quantified in the same detail offered by 2D-based techniques. This aspect has only recently started to become a reality for 3D X-ray computed tomography measurements, given innovations dedicated to the raw materials sector. Currently, Xray computed tomography analysis offers the potential to characterise particle microstructures in 3D – essential information for a better understanding of mineral separation processes. Hence, it has a considerable impact on improving the efficiency of the mining industry and potentially reducing technical as well as environmental risks. In this study, the flotation of a sulphide-rich ore is investigated with the goal of quantifying, for individual particles, the relation between their microstructural properties, their behaviour in the process, and the flotation cell hydrodynamic conditions. A combination of 2D mineral liberation analysis and 3D X-ray computed tomography is used for respectively characterising fine and coarse particles. This particle data is then applied to model the process behaviour of individual particles in the flotation experiments. Factors such as particle size, shape, liberation, and association are taken into account. Given the more detailed description of particle geometric properties provided by x-ray computed tomography, a more precise
evaluation of the influence of particle shape in the flotation process, both in the recovery of ore minerals (mostly via true flotation) and of gangue minerals (mostly via entrainment). The research findings out that higher turbulence in the cell results in better recovery of fine particles, whereas the recovery efficiency of coarse particles is negatively impacted by higher energy dissipation within the cell. The methodology applied here, both for characterising individual particles in 3D and for modelling mineral separation processes at the level of single particles, is also applicable to other ores and mineral separation units.