Abstract: A flotation apparatus including: an elongate vertical riser (142) in which a cocurrent flow of gas/slurry liquid mixture rises upwards to a discharge mouth at its top end; an aeration unit (140) provided at a lower end of the riser; a separation unit (150) provided at the top end of the riser; and wherein the height of the riser is selected to produce substantially turbulence free flow in which a high gas lift occurs in the riser such that a pressure drop between the liquid inlet and the discharge outlet of the aeration unit is sufficient to produce gas particle dispersion and recirculation of the slurry liquid through the flotation apparatus.

Abstract: A multi-phase staged passive reactor (10) for promoting interphasic interaction of a first substance in a liquid phase with a second substance in a non-miscible liquid phase, a solid phase or a gaseous phase. The reactor comprises a plurality of stages (C, D and E) which define a flow path for the substances in different phases. Each stage is shaped to define a substantially curved flow path (12) having a center of curvature located to one side of the flow path (12). Thus, for example, stages (D) and (E) have a respective center of curvature (14, 16), on opposite sides of the flow path (12) whereby, in use, as the substances flow through the reactor (10) particles of the second substance are forced to migrate through the first substance, first in one direction and then in substantially the reverse direction due to an inertial field of changing direction thus generated.

Abstract: A method of gas particle formation in a liquid medium comprising the steps of: forming a substantially continuous film of gas on a surface having a discharge edge submerged in the liquid medium; generating a flow of liquid over the surface, adjacent to and co-current with the film of gas, directed towards the discharge edge; and breaking the gas film into gas particles by shear forces as it approaches and/or escapes from the discharge edge.