Coal Preparation » Gravity Separation
This report concerns testing of the Gekko IPJ Coal Separator 1000 unit at a coal preparation plant in the Hunter Valley. The unit was tested with feed in the 6 x 0 mm size range with three different coals and feed solids concentrations varying between 16.0% and 26.3%, volumetric feed rates between 7.9 m3/h and 29.6 m3/h and dry mass feed rates between 3.2 t/h and 10.3 t/h.
For the cases in which partition coefficient curves were determined, the separations were more efficient using the 1000 mm unit in the Hunter Valley than the 600 mm unit used in the laboratory. Unlike conventional jigs where efficiency is related to length and capacity is related to width, the Gekko IPJ Coal Separator circular design enables both capacity and efficiency to improve with radius. That is, increasing the capacity inherently improves separating efficiency.
The Gekko IPJ Coal Separator produces a clean product. That is, the high density tail of the partition coefficient curve tends to be minimised. The extent of the low density tail is controlled by the depth of ragging. Four layers of ragging were found to minimise the low density tail, particularly at higher feed tonnages. The device has particular applications where a product devoid of contamination is an advantage. Industrial applications in this regard include those situations where parallel circuits, eg dense medium cyclone circuits, process high levels of near gravity material. In such circumstances a low ash fines product would permit dense medium cyclone medium densities to be increased, with commensurate yield increases.
The Gekko IPJ Coal Separator makes efficient separations in the 1.43 - 2.0 RD range for particles in the 6 x 2 mm and 2 x 0.25 mm size ranges and as such has direct application in the Australian coal industry. It is likely that the unit can effectively process a wide range of particle sizes and straight forward minor design changes have been identified that would enhance the performance of the unit further.