Superficial gas velocity (Jg) is a measure of the aeration ability of a cell and is directly related to the flotation kinetics.  If the superficial gas velocity is too high, however, the entrainment of gangue material into the froth phase may become excessive, and reduce the froth stability, as well as decrease the concentrate grade.  Measuring the superficial gas velocity at various locations across the cell cross-sectional area has been shown to give a good indication of how well the air is dispersed in the cell.

The JK Jg probe consists of a perspex tube with a valve at one end, and a water inlet and an air release valve at the other end.  The probe is lowered into the flotation cell, generally just below the pulp-froth interface and filled with water.  The air release valve is closed to the atmosphere, and the valve at the bottom is opened to allow gas from the cell to flow into the probe.  This gas displaces the water within the probe at a rate equal to the velocity flowing within the cell, and is measured by the time required for the water level to drop a pre-determined distance.  Corrections are made for pressure, based on the length of the probe and the distance the probe is immersed in the pulp phase. 

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