Froth flotation apparatus

A froth flotation apparatus for treating a mineral feed stream, the apparatus comprising a tank defining an interior for holding a slurry, at least one contactor in the tank, at least one aerator for aerating the mineral feed stream to provide an aerated mineral feed stream, a system for feeding the aerated mineral feed stream into the contactor, an agitator to shear the aerated mineral feed stream in the contactor, the contactor including a plurality of exit zones, which are spaced vertically from one another at intervals along a length of a contactor zone at which the aerated mineral feed stream can exit the contactor and enter the interior of the tank, each exit zone including a first plurality of outlets in a wall of the contactor and being positioned immediately below a corresponding rotor-stator assembly, and a control mechanism, in the form of a respective circular sleeve formed with a second plurality of outlets which surrounds each exit zone, the sleeve being rotatable relative to the contactor to regulate the release rate of the aerated mineral feed stream from each of the exit zones.