The permanent magnetic separator is widely used in the separation of magnetite, the recovery of magnetic additive and the pre selection of the wet strong magnetic separation.
2.Structure of magnetic separator
It is mainly composed of magnetic system, cylinder, sorting trough, transmission device, feed, discharge and overflow device etc. The arrangement of magnetic system and the number of magnetic poles have a decisive influence on the results of the separation. According to the diameter of the cylinder, the magnetic pole is generally 4-7 poles, and the polarity is alternately in the direction of the circumference. The cylinder is used to adsorb and transport magnetic particles and to prevent the slurry from immersing in the magnetic system. The cylinder and its end cover are made of nonmagnetic, high resistivity and corrosion resistant materials. The sorting tank is made of austenitic stainless steel and are lined with rubber or synthetic materials to prevent wear. Generally, the gear motor or Y series motor is rotated by the reducer to drive the drum.
3.Magnetic system material
Magnetic separator is usually made of strontium ferrite and barium ferrite permanent magnet material. In recent years, rare earth permanent magnet materials such as Nd-Fe-B magnetic steel have been used to make magnetic blocks, although the latter has higher cost, but the magnetic properties are excellent and the amount of them can be reduced. At present, the composite magnets of ferrite permanent magnets and rare earth permanent magnets are commonly used, which greatly improves the performance of the magnetic separator and expands the scope of application of the magnetic separator. In recent years, the magnetic system composed of rare earth permanent magnets has been used to achieve higher magnetic field strength and performance.
4.Kinds of magnetic separator
The drum magnetic separator has 3 kinds of tank structure, i. e., the downstream flow (S) counterflow (N) and the half counterflow (B), and the proper sorting size is -6mm, -2mm and -0.5mm. The suitable tank type can be selected according to the ore property and the mineral processing process.
4.1.CTB half counterflow magnetic separator
The magnetic separator is a half counterflow type, and its structure is like Figure 1. From the bottom of the tank to the bottom of the drum, the movement direction of the non-magnetic product is opposite to that of the drum, and the direction of the moving direction of the magnetic product is the same as that of the drum. The tank with this characteristic is called the half counterflow type body. The application of non magnetic materials to the parts of the body near the magnetic system, the rest made of ordinary steel plates, or made of hard plastic plates.
Figure1.CTB half counterflow magnetic separator
1. drum, 2. magnetic systems, 3. tank, 4. magnetic guide plate, 5. frame, 6. water spraying pipe, 7. ore feeding box, 8. drum, 9. magnetic system, 10. tank,.11. magnetic guide plate, 12. frame,13.water spraying pipe, 14.feeding box
The bottom part of the tank is for the ore feeding area, with a sprinkler pipe inserted to regulate the pulp concentration of the sorting operation. The slurry is blown into a loose suspension state to enter the separation space, which is conducive to improving the selection index.
There is a bottom plate on the upper part of the ore feeding area, and a rectangular hole is opened on the floor, and the tailings are outflowed. The gap between the bottom and the drumr is related to the granularity of the magnetic separator.
Magnetic properties of 750mm and 1050mm magnetic separators, such as figure 2.
Figure 2.CTB magnetic separator Magnetic properties
ⅠSorting area; Ⅱ.transport area; Ⅲ.dewatering area
Sinonine company added the auxiliary pole with the same polarity as the main pole in the polar gap of the open magnetic system with regular arrangement (Figure 3), which not only enhanced the magnetic field intensity, but also changed the magnetic field characteristic. The average field strength of the drum surface of the magnetic separator with the new magnetic pole structure is up to 160KA/m, and the magnetic separator with this magnetic system has obtained good selection effect.
Figure 3.T type magnetic pole structure
4.2.CTS downstream magnetic separator
The structure of the separator is downstream type (Figure 4). The direction of ore feeding is consistent with the direction of rotation of the drum or the direction of magnetic product moving. The pulp is directly under the magnetic system of the drum from the feeding box. The non magnetic ore particles and the weakly magnetic particles are discharged from the gap between the two bottom plates below the drum. Magnetic particles are absorbed on the surface of the drum, rotating together with the drum, and expelled at the weak magnetic field at the edge of the magnetic system. This magnetic separator is suitable for the coarse selection and clean selection of the strong magnetic ore of 0-6mm.
Figure 4.CTS downstream magnetic separator
1.drum；2.tank；3.feeding box；4. Transmission；5.ore unloading water pipe；6.discharge adjust valve；7.frame；8. magnetic declination adjustment device
4.3.CTN counterflow magnetic separator
The structure of the magnetic separator is a countercurrent type (Figure 5). The direction of the feed is opposite to the direction of the rotation of the drum or the moving direction of the magnetic product. Ore pulp is directly from the feed box to the magnetic system of the drum. The non-magnetic mineral particles and the weakly magnetic ore particles are discharged from the tailings holes on the bottom plate of the left edge of the magnetic system. The magnetic ore particles move along the drum to the ore direction and move to the concentrate outlet end, and into the concentrates. It is suitable for the coarse selection and cleaning of 0-0.6mm strong magnetic ore, as well as the heavy medium recovery in the coal preparation industry. This magnetic separator is not suitable for handling coarse - grained ores, because when the size of the particles is coarse, the deposit will block the separation space.
Figure 5.CTN counterflow magnetic separator
1.drum；2.tank；3.frame；4. Transmission；5. magnetic declination adjustment devic
5.specification of magnetic separator
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Optimized computer design ,rational magnetic circuit, strong magnetic coercive force and high-remanence permanent magnetic which can keep the magnet performance in a long period and safeguard the long -term interest of the customer, the whole structure is reliable.
Slurry enters chute through ore tank, and then gets into separating zone by waterpower. Minerals with strong magnetism are absorbed on the drum’s surface under the force of magnetic field and get into the ore concentrate outlet along with the rotation of drum. After leaving the magnetic field, they flow into ore concentrate box by the action of gravity and flushing water. Gangue and ore with weak magnetism are discharged into a pipe in the opposite direction of drum rotation.