CYCLONES

In Cyclones the small particles are separated by centrifugal and vortex action (the cyclone itself does not move). The water/particle mixture is pumped into the side of the cyclone tangentially and swirls around creating a vortex in which the lighter particles are sucked to the middle and out to a dewatering screen.

The heavier particles are thrown by centrifugal force to the wall of the cyclone and are discharged at the opposite end.
Cyclones can be used alone or in a system with natural medium or dense medium drums. Larger plants may include banks of cyclones operating together.

Cyclone-only plants are suitable for the cleaning of small coals of less than 50mm particle size.

NATURAL MEDIUM CYCLONE More info...
This is used to separate particles of different density in a viscous medium.
The natural medium cyclone is mounted horizontally.

DENSE MEDIUM CYCLONE More info...
This is used for very accurate separation of particles of different density. Particles smaller than 0.5mm are removed from the mixture before it enters the cyclone.
Magnetite is added to the water/particle mixture to allow precise control of density.
The dense medium cyclone is mounted at a 15° angle. The lighter particles (coal) come out of the upper end and the heavy particles (high ash coal or shale) the lower.

WATER-ONLY CYCLONE More info...
This is used in Fines Coal Recovery Plants and can recover particles of <5mm x 100 microns. It operates in exactly the same way as a natural medium cyclone.

CLASSIFYING OR SAND CYCLONE More info...
Used for separating particles of different sizes the classifying cyclone is mounted vertically. The smaller particles come out of the top and the larger particles out of the bottom or spigot.
This equipment is also known as a sand cyclone in the quarrying industry and is suitable for classifying
particles from <5mm with cut point as low as 20 microns.