|
|
||
| PRESENTATION | ||
|
The Jig Cyclone develops of a new principle of gravimetric concentration of very fine particles. Patent : cf WIPO cf ESPACENET cf EPO
|
||
|
The Jig Cyclone is a static machine which works continously. It is fed by a slurry pump and a water pump which can be slightly charged. |
||
|
Pulp (mixture of solid particle in a fluid) is centrifuged on a prismatic wall's cavity in the shape of spiral in order to decrease in a continuous way the centrifugal acceleration and to concentrate it punctually. A sheet of water is injected in a point corresponding at an end of the spiral at a linear velocity similar to that of the slurry. At each rotation, the slurry must overlap the sheet of water at the point corresponding to the specific increase in centripetal acceleration. The gravimetric separation is carried out within a thick pulp in which the particles are obstructed mutually in their displacement. This particular movement of the particles is called hindered sedimentation. Several solutions exist to increase the dynamics of the particles in this thick medium: the shearing generated by differential speeds, the jigging, and fluidization. The Cyclone Jig is alone calling upon these three modes of increase in the mobility of the particles. The gravimetric separation of the particles is also generated by subjecting them to cycle of acceleration since their displacement during acceleration is independent of their dimension. This mechanism appears in the jigs. |
|
When the grain size decreases, the period
of acceleration decreases and it is the reason which explains the need for
increasing the frequency of the pulsations of the jigs. This increase in
frequency becomes a mechanical problem for the very fine particles which
requires very high frequencies. The Jig Cyclone circumvents this problem
by generating these accelerations by the overlapping of the sheet of water
injected. The frequency is then equal to the revolutions speed which are
about 5000RPM. The sedimentation speed of very fine particles are thus increased by centrifugation in a prismatic cavity of diameter D where the particles circulating at the speed V are subjected to acceleration centrifuges V2D. The speed of the slurry is limited because of the energy expense which depends on its square. To arrive at very high accelerations, the solution is to reduce the diameter of the cavity of centrifugation. |
|
The test are done on a synthetic mixture crushed at the same d50=35µ White sand (d=2,6) and black chromite (d=4,75)
|
|
|
|
|
