The drum of the centrifugal concentrator rotates at a high speed at a certain number of revolutions, and the slurry is fed into the inner wall of the drum in two places through the ore feeder and the ore feeder. The slurry rotates with the drum at high speed. Under the action of centrifugal force, heavy minerals are deposited on the inner wall of the drum and rotate with the drum. The light mineral particles in the slurry rotate with the drum at a certain differential speed. During the rotation, they rotate at a certain speed. The spiral angle rotates from the ore feeding end to the ore discharge end along the slope direction of the drum, and is discharged through the ore discharge separator at the end, which is the tailings.
After 3 minutes of sorting, the ore feeder and distributor automatically rotates away from the original normal position and stops feeding the ore into the drum. After the tailings are discharged, the ore distributor automatically rotates away from the original normal position and prepares to intercept the concentrate. , then the high-pressure flushing water valve opens automatically, and the high-pressure flushing water flushes down the concentrate deposited on the inner wall of the drum. After the concentrate is flushed, the high-pressure water valve automatically closes. After the concentrate is drained, the ore distributor and feeder The ore separator automatically resets to start the next sorting cycle.
When the water flow rises, the bed is lifted up and becomes loose and suspended. At this time, the mineral particles in the bed move relative to each other according to their own characteristics (density, particle size and shape) and begin to stratify. Before the water flow has stopped rising but has not yet turned into a downward flow, the mineral particles are still moving due to the inertial force, and the bed continues to be loose and stratified. The flow turns downward and the bed gradually compacts, but stratification continues. When all the mineral particles fall back to the screen surface, they have lost the possibility of relative movement between each other, and the stratification basically stops. At this time, only those mineral particles with higher density and very fine particle size are still moving downward through the gaps between the bulk materials in the bed. This behavior can be regarded as the continuation of the stratification phenomenon.
The descending flow ends, the bed is completely compact, and stratification is temporarily terminated. The time it takes for the water flow to complete each cyclic change is called the jig cycle. During a jig cycle, the bed undergoes a process from compact to loose stratification and then compact again, and the particles are sorted. It is only after several jigging cycles that the layering is gradually perfected. Finally, high-density mineral particles are concentrated in the lower part of the bed, while low-density mineral particles are concentrated in the upper layer. Then, they are discharged separately from the jig, thereby obtaining two products with different densities, that is, different masses.
Compared with the flat chute, the centrifugal concentrator has the following advantages:
(1) The centrifugal concentrator is more effective in processing fine sludge, and the recovery rate for particle sizes of 37-19 microns is as high as about 90%. Because the separation of ore particles in the centrifugal concentrator is based on the combined action of centrifugal force and cross-flow membrane, its enrichment ratio is higher than that of the planar gravity chute.
(2) Because the centrifugal concentrator uses centrifugal force, it strengthens the gravity separation process and shortens the separation time. Therefore, its processing capacity is large, about 10 times that of the automatic chute.
(3) Small footprint and high degree of automation.
Its main disadvantages are: (1) It consumes more water and electricity than a flat chute; (2) The slope of the drum wall cannot be adjusted, the production process is intermittent operation, and the ore cannot be fed continuously, but two units can be connected using valves to achieve automatic discharge.
The centrifugal concentrator has become one of the main equipment for tungsten-tin ore slime gravity separation in my country. In recent years, it has been tried for the beneficiation of lean iron ore. The centrifugal concentrator is still being continuously improved and perfected. While improving the separation indicators of the mineral processing equipment, it is focusing on developing towards large-scale and continuous development.
