In a flotation cell, turbulence influences the motion of solid particles relative to the bubble surface, and, thus,
affects the recovery rate. But, the impact of turbulence on the probability of a bubble-particle aggregation
is still difficult to measure, especially in a dense flow. Therefore, the focus of this work was to apply
Positron Emission Particle Tracking (PEPT) as a method to investigate the effect of turbulence on the
particle movement and bubble-particle interaction in an opaque flow. Single air bubbles (db = 2.5 mm) were
generated on a needle in a water flow channel. Upstream, a grid produced an isotropic turbulent flow with
5 % to 15 % turbulence intensity and a Kolmogorov microscale of 20 µm. Depending on the distance to the
grid, the flow near the captive bubble (Reb ≈ 450) was characterized by eddies of different length scales
and magnitude with tomographic Particle Image Velocimetry (PIV). The solid suspension contained up to
0.3 % polymethylmethacrylate (PMMA) particles (dp = 200 µm–400 µm) and up to six radiolabelled particles
(dp = 300 µm–400 µm) coated with PMMA. The trajectories of the labelled particles were used to determine
the average particle distribution in the turbulent field and describe the bubble-particle interactions. These
results provide valuable information on the applicability of PEPT in turbulent and dense flow fields as well
as on particle trajectories close to bubbles, enhancing our understanding of key flotation phenomena.