A mechanical flotation cell essentially consists of a vessel or a tank fitted with an impeller or rotor. Rotor (impeller) is one of the main components of a mechanical stirring flotation machine, which is to stir pulp, circulate pulp, absorb air and disperse air.
The impeller or rotor, also referred to as the agitator, is considered to be the heart of a mechanical flotation cell as it provides the energy to perform the following functions necessary for the flotation process:
The impeller agitates the slurry to keep particles in suspension, disperses air into fine bubbles and provides an environment in the cell tank for interaction of bubbles and hydrophobic particles and their subsequent attachment and therefore separation of valuable mineral particles from the undesired gangue mineral particles.
When impeller rotates at high speed, a negative pressure is formed in the center, thus air in the conduit is absorbed in, and slurries are absorbed in from side hole or cover plate hole, consequently forming a three-phase flow of solids, liquid and air. With the effect of centrifugal force, the three-phase flow of solids, liquid and air flows outside. When the three-phase flow goes through the cover plate screen, the flow speed is reduced, then air-phase is changed to tenuous foam. This circulation helps to mix the three phases and foam becomes mixed slurries.