Gas hold-up (e_g) measures the volume fraction of air contained within the pulp phase of the flotation cell.  Generally increasing the gas content within the cell results in more bubbles per unit volume and hence more available surface area for particle-bubble interactions to occur, producing improved kinetics in the pulp phase.  However, there is a maximum value of gas hold-up before the cell capacity is limited, resulting in reduced residence time.

The probe takes a sample of aerated slurry from just below the pulp/froth interface.  The instrument consists of a vertical cylinder with either pneumatic or mechanical valves at the top and bottom.  It is lowered into the flotation cell and slurry is allowed to pass through the probe for at least 10 seconds.  After this time, the top and bottom valves are rapidly closed and the probe lifted out of the flotation cell.  The volume of the slurry collected, Vs, is measured and compared with the known volume of the probe between the two valves, Vp.

Key Contact:  Dr Rolf Fandrich, Products and Sales Manager.