Technological assessments on recent developments in fine and coarse particle flotation systems

After more than a century applying flotation to the mining industry, two completely different strategies have been introduced for processing purposes. One is the classical approach viz. grinding ores to a certain extent (fine particles) and floating them via conventional mechanical and pneumatic cells i.e., Jameson, ImhoflotTM and RefluxTM. This strategy continues because mines face declining cut-off grades, complex and poly-mineralized ores, and they are required to achieve an acceptable degree of mineral liberation. The other school of thought deals with coarse particle processes mainly owing to the low energy requirements, that includes SkimAir (R) flash, fluidized bed and HydroFloatTM cells. There is no study in the literature to comparatively present the recent developments of flotation apparatuses versus the conventional mechanical cells. To cover this knowledge gap in the literature, the present paper endeavors to critically evaluate these concepts from several points of view, including existing technological advancements, water and energy usage, kinetics, and circuit design. A brief introduction of advanced technologies, along with their applications is presented. The data from literature and case studies showed that the Jameson, ImhoflotTM and recently developed RefluxTM flotation cells can be very effective for recovering fine particles owing to their specific hydrodynamic designs, intensive energy dissipation rate and generation of micron-sized bubbles (100-700 mu m). Very low (less than a few minutes) mean particle residence time, high gas-hold up (ca. 50-70 %), no agitation and high efficiency of particle-bubble collision were identified as their main advantages compared to traditional mechanical flotation cells. In addition to their common applications in cleaner stage, these cells were used in pre-flotation and scalping (producing final concentrate from the rougher feed) duties. Their main challenges were recognized as relatively unclear procedure on their scale up/down, optimization and simulation. The HydroFloatTM cell was indicated as a promising technology for recovering coarse particle fraction sizes by taking advantage of the fluidized-bed concept with plug-flow dispersion regime, high particle residence time, and limited cell turbulence. We finally concluded that fine particle flotation may remain as the main focus of re-processing tailings dams, while coarse particle treatment should be the focus of this century to reduce total energy consumptions.

Automated summary

This paper critically evaluates the two different strategies in ore flotation processing: the classical mechanical flotation cells and the new flotation apparatuses. Through a comprehensive comparative study, it is found that the traditional mechanical cells are suitable for fine particle flotation, while the new apparatuses such as Jameson and RefluxTM flotation cells are highly efficient in recovering fine particles. In addition, fluidized bed and HydroFloatTM cells are suitable for coarse particle recovery.