Turbulence in stirred tank flotation tanks impacts the
bulk transport
of particles and has an important role in particle–bubble collisions.
These collisions are necessary for attachment, which is the main physicochemical
mechanism enabling the separation of valuable minerals from ore in
froth flotation. Modifications to the turbulence profile in a flotation
tank, therefore, can result in improvements in flotation performance.
This work characterized the effect of two retrofit design modifications,
a stator system and a horizontal baffle, on the particle dynamics
of a laboratory-scale flotation tank. The flow profiles, residence
time distributions, and macroturbulent kinetic energy distributions
were derived from positron emission particle tracking (PEPT) measurements
of tracer particles representing valuable (hydrophobic) mineral particles
in flotation. The results show that the use of both retrofit design
modifications together improves recovery by increasing the rise velocity
of valuable particles and decreasing turbulent kinetic energy in the
quiescent zone and at the pulp–froth interface.