Froth liquid transport in a two-dimensional flotation cell

Abstract A study of froth liquid transport in flotation cells with very low bubble loading was performed in a two-dimensional flotation cell using a two - phase (air–water) system. The prototype represents a radial section of an industrial flotation cell (130 m 3 ) and was operated at steady state. The experimental tests consisted of adding a small amount (0.02 mL) of radioactive liquid tracer I 131 (in a NaI solution) on top of the froth (TOF) or near the bottom of the froth (interface). Eight collimated sensors located along the froth and collection zones allowed the evaluation of liquid transport and drainage in the froth after tracer addition at different distances from the discharge lip. Longer distances to the overflow discharge lip promote higher water drainage from the froth to the collection zone. For the liquid content near the top of the froth, the liquid drainage increased gradually from almost nil to approximately 50% when the distance to the lip level was increased from 5 to 98 cm. In contrast, the liquid content in the froth near the interface was almost fully drained for distances larger than 15 cm from the discharge lip. This information was complemented by froth surface velocity measurements using the Visiofroth system and showed a good agreement with the liquid transport velocity measured near the discharge lip wall. The increase in the frothcrowder angle (40–50°) also showed a significant effect on the froth liquid transport velocity and similar drainage characteristics.