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Froth flotation is an important operation for the recovery of valuable minerals in the mining industry. The essence of flotation processes lies in the interactions between particles and bubbles, which can be categorized into three successive sub-processes which are bubble-particle collision, attachment and detachment. These three sub-processes determine the overall performance of flotation processes for treating a particular ore.
There are limitations of flotation operation in treating particles of different sizes . This size limitation can be varied for different type of ores and flotation works well for particles of base metal ores in the range 20 to 150 μm in diameter . Recovery of fine and coarse particles declines progressively and underlying reasons are different depending particle size .
Fine particles with small inertia will more likely follow streamline and therefore have lower chance of colliding with a bubble . Though this is not a problem for coarse particle flotation, coarse particles with higher inertia would more likely detach with modest disturbances from surrounding liquid motion . Therefore, studying interactions between particles and bubbles are fundamental to improve flotation performance. It is unavoidable that fine particles are produced in the grinding processes for the beneficiation of minerals . Moreover, it is desirable to treat coarse particles using flotation for the early rejection of gangue as large amount of energy can be saved in the comminution processes . It is highly necessary for studying particle-bubble interactions under the effects of turbulent flows as they are limiting factors in determining flotation performance .
Studies have been directed towards expanding size limit  and manipulating particle-bubble capture . Studying particle-bubble interactions in turbulence is key to expand size limit and improve flotation performance. We have done a systematic endeavor to understand the effects of turbulence, especially on particle-bubble collision and particle detachment. Critical literature reviews on separate sub-processes have been presented on particle-bubble collisions , attachment  and detachment . It is desirable to combine these three sub-processes together and consider the effects of turbulence on the flotation process as a whole. The effects of turbulence on the particle-bubble interactions in general is considered to be a stochastic process . It can be attributed to the dynamic interactions between particles or bubbles with the turbulent eddies in flotation environment. On one side, hydrodynamics in flotation machines need to be characterized , and on the other side, how turbulence control sub-processes in flotation machines should be examined . In this way, hydrodynamics in flotation machines can be optimized to improve flotation performance . Though some classical work in old days have been cited, we aim to collect literature in this century.
2. Particle-Bubble Collision, Attachment and Detachment
2.1. Effects of Turbulence on Collision
This entry is adapted from 10.3390/min11091006
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