Positron emission particle tracking (PEPT) can be used to determine the path of hydrophobic tracer particles inside flotation vessels. To measure high particle speeds near the impeller (1 m/s), a tracer particle must be radiolabeled with approximately 600 μCi (22.2 MBq) of the positron emission tomography (PET) radionuclide ~(68)Ga. This requires larger tracer particles (>500 μm) and makes PEPT directly applicable to coarse particle flotation in the pulp. In the froth, the particle speed is significantly lower (1 cm/s), which enables the use of smaller tracer particles, with corresponding lower activity levels of ~(68)Ga. The simultaneous tracking of multiple tracers increases the amount of data collected to perform time averaged analysis of particle motion in the froth. Five smaller particles (200-300 μm) were tracked in the froth zone of a laboratory-scale flotation vessel with PEPT facilitating detailed analyses of particle behaviour in the froth.
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