Dry strong magnetic separation of manganese ore (2)

  1. Electromagnetic System electromagnetic system is the main component of the machine, the machine for generating a strong magnetic field of the separation zone, the whole machine exciting coils (11) are each mounted on two four iron core (13), and a four Two series connection method (see Figure 4). The excitation current communicates with the other set of cores through the sorting gap through the magnetic flux excited in the core through the pole (9). The magnetic flux generated by the coils is connected in series to each other to form a complete main magnetic circuit (see Figure 5).

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2. Induction Roller The induction roller is a direct working part of the machine. It consists of 26 shaped sprocket wheels and aluminum shrouds and intermediate discs of various specifications. It forms the main magnetic circuit with the iron cores I and II.
3. Transmission system This system consists of two JO ₂ -61-6 (n=970r/min, P=l0kW) three-phase asynchronous motors, which are driven by the V-belt to reduce the left and right induction rollers, respectively, in the reducer and induction roller. Connected with a cross slide coupling.
4. The mining bucket is the container for receiving and separating the products after the minerals are sorted by the induction shaft. The middle part is divided into the distribution board, the separation board, the top edge of the separation board to the axis can be adjusted, and the angle of the distribution board is swung. Can be adjusted as needed within the 18° range.
5. Cooling and Ventilation System This system consists of a centrifugal fan, a duct and a ventilating hood. When the fan is running, a certain air volume and wind pressure are formed in the hood, so that the excitation coil sealed in the hood is cooled.
6. Rack The full frame is made of steel welded, and the upper part is connected by screws and base beams, which are the load-bearing parts of each system.
In the development and production process of coarse-grained magnetic separator, several problems are worth discussing:
(1) First of all, it is the problem of processing capacity. In order to reduce the burden of the coarse ore particles to increase the magnetic load, the upper part is usually used for the mineral mud. Therefore, the ore is required to be evenly and orderly, which will be beneficial to the sorting effect and improvement. Yield. In order to explore the processing capacity of the equipment, the 80-1 type magnetic separator is taken as an example to theoretically calculate its processing capacity. The 80-1 type magnetic separator has an induction roller diameter of 380 mm and a rotational speed of 35 r/min. Therefore, the linear velocity can be calculated to be 0.696 m/s. Assuming that the ore is an ideal uniform continuous feed, then the theoretical calculations as listed in Table 3 will be obtained.

According to the ratio of the fine-grained and tailings particle size composition to the fine and tailings yield, the theoretical output should be 41.25~44.71 t/set, and our production is only 6.06t/set, which is several times different from the theoretical quantity. There are many. It should be said that the potential of this equipment is still very large, the key is how to rationally develop.
(2) Secondly, it is the distribution characteristics of the magnetic field strength in the sorting area. There are many factors affecting the sorting effect of minerals in the sorting area, but the distribution of magnetic field strength in the sorting area is the decisive factor.
The force of the mineral in the magnetic field can be simplified as shown in Figure 6.

F is the gravity component of the normal direction of the roll surface; gcosa is the gravity component of the normal direction of the roll surface; gsina is the gravity component of the tangent line of the roll surface; Ï… ² /R is the centrifugal force of the normal direction of the ore; a is the axis The angle between the positions of the ore particles on the surface. [next]
In order for the magnetic mineral to be firmly attracted to the induction roller, it must be a force greater than the combined force of centrifugal force and gravity. Otherwise, the mineral will leave the roll surface and enter the tailings, which will not be sorted. After entering the sorting magnetic field, the minerals will be affected by the various factors shown in Fig. 6. They will also be interfered by the minerals, so it is difficult to analyze the movement trajectories of the minerals in the magnetic field during the movement. But in practice, roll is induced in the stationary state, i.e. the frictional force is zero, when the centrifugal force is equal to zero, it can be found different size fractions of magnetic minerals (hard manganese ore) and a position away from the non-magnetic minerals sensing roller and the point The magnetic field strength is shown in Table 4.

It should be noted that the minerals used in the test are arbitrarily selected from the production site. The relevant data is the average value of the multiple measurements of each mineral, but the measurement method is still rough, and the phenomenon is very obvious. The non-magnetic ore particles leave the induction roller before 45°, and the magnetic ore particles gradually increase as the particle size (also referred to as mass) becomes smaller. Test results to determine a clear industrial production of revelation, the mineral matter size range should not be too wide, otherwise separating different angle, easy to mix the non-magnetic ore particles. At the same time, the high magnetic field in the sorting area should be moved up as much as possible to avoid the coarse-grained magnetic minerals from prematurely leaving the roll surface due to insufficient magnetic force and mixed with non-magnetic mineral particles.
One problem to be emphasized is the shape and mounting position of the partition plate. The mineral moves in the magnetic field, and different motion trajectories are generated due to different factors such as the magnetization coefficient. Separator is the main component that distinguishes between magnetic and non-magnetic minerals. The sorted mineral is a magnetic field driven by a cylindrical induction roller. When it leaves the surface of the induction roller, it is a parabolic trajectory. Its initial velocity is curved. If the partition plate is also curved, it can be accurately installed from the tangential direction. Effectively separate magnetic minerals from non-magnetic minerals. Secondly, the partition plate must be installed below the induction roller and the magnetic pole head. At this time, the mineral running track has been deformed, and gravity has played a leading role. Therefore, they are separated in the vertical descent period, which tends to cause a denser non-magnetic mineral to be mixed into the magnetic mineral. Two phenomena were observed in the production practice: First, the non-magnetic minerals collided with the magnetic poles and rebounded into the magnetic minerals after leaving the surface of the induction roller; another phenomenon was that the non-magnetic minerals hit the top of the partition plate and fell to the surface when they fell. In the magnetic mineral, if the partition plate is raised, on the one hand, the rebound phenomenon can be avoided, and the magnetic field strength on the surface of the induction roller can be compensated for. The effect of coarse-grained strong magnetic separation and separation of manganese oxide ore is shown in Table 5.

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In the 1990s, there was a boom in the use of permanent magnet magnetic separators to replace electromagnetic induction magnetic separators. This is mainly the original permanent magnet materials barium strontium ferrite, neodymium-iron-boron material is improved (also called a rare earth magnet block type), Gui Lin Tianyun processing machinery plant, factory Liuzhou Yuanjian magnetic device developed by CRIMM, The Yu-type permanent magnet strong magnetic separator has been promoted in manganese mines in Hunan, Guangxi, Yunnan and other places, and has achieved certain economic benefits. The technical and economic indicators for sorting are shown in Table 6.

It should be specially pointed out that the selection of coarse-grained ore should focus on overcoming the large gravity of the coarse particles themselves. Therefore, most of the strong magnetic separators for selecting coarse-grained ores are in the upper ore-feeding form and are carried out in an air medium. Therefore, there are strict requirements on the water content of the selected ore. Otherwise, the capillary adsorption phenomenon caused by the wetting between the ores will affect the separation effect of the magnetic force. At the same time, because the sorting is carried out in the air, the operating environment is poor, and ventilation and dust removal facilities should be added.
For manganese ore, pre-enrichment by coarse-grained magnetic separation has broad development prospects, especially in China, manganese ore is poor, fine and miscellaneous. Therefore, pre-enrichment is an indispensable task and should be developed vigorously.
Second, the strong magnetic separator of medium particles
The meaning of the medium particle is 5~1mm in the field of manganese ore processing. Due to the higher sorting magnetic field of some magnetic separators, the upper limit is also expanded to less than 7mm.
The strong magnetic separator for processing particles is basically a lower-feeding, wet-type, electromagnetic induction roller type strong magnetic separator. In China, the Gc-200 strong magnetic separator of the former Soviet Union was introduced from the Shenyang Mine Manufacturing Plant. The machine was first tested in the Xiangtan Manganese Mine. However, due to the small particle size and low magnetic field strength, it could not be obtained. Promotion. The medium-particle strong magnetic separator, which is more mature and widely used, should be a CS-1 electromagnetic induction roller type strong magnetic separator jointly developed by Maanshan Research Institute and Bayi Manganese Mine. The machine was supplied with design drawings by the Maanshan Mine Research Institute in 1978. The Bayi Manganese Mine was manufactured and rectified several times due to certain defects during the development process. Made in 1979 and put into trial operation for up to two years, in May 1982 technical appraisal by the Ministry of metallurgical industry organizations.
(1) The CS-1 electromagnetic induction roller type strong magnetic separator has been successfully developed. The structure is basically reasonable, the operation is stable, the work is reliable, the operation is convenient, and the maintenance is easy to maintain.
(2) The machine has different performance materials for the induction shaft and the shaft head. The joint structure of the shaft head and the roller body adopts a combined structure, and the design parameters of the roller teeth are reasonable. Due to various measures to reduce the leakage of the machine, the magnetic field distribution between the shafts is relatively uniform, and the optional index is better. A new type of machine has been developed for the selection of medium-particle lean manganese oxide ore and weak magnetic ore. According to the data currently available, there is no such medium-grain induction roller type strong magnetic separation equipment with high field strength, large processing capacity and high-density particle size combination. This machine is in a leading position. [next]
The structure of CS-1 type electromagnetic induction roller type strong magnetic separator is shown in Fig. 7. The sorting process is shown in Figure 8.

The raw ore input to the mine box 4 should be evenly distributed over the length of the supply tank, and the feed roller 11 is provided in the supply tank. When the magnetic separator is started, the feed roller is driven by the chain drive of the induction roller 1. When the roller rotates, the ore is pulled out from the peach-shaped hole on the side wall of the ore tank, and the induction roller is fed along the slide and the wavy plate. The sorting gap between the pole and the pole (also known as the seat). In the gap, due to the strong magnetic field caused by the local electrode system, the ore is divided into two parts, namely the magnetic part (concentrate) and the non-magnetic part (tailing). The rotating induction roller carries the concentrate into the concentrate tank 12, and the tailings flow from the sorting zone into the tailing bin 13 through the comb-toothed notch of the pole head. The discharge concentrate and tailings are carried out by means of a spherical valve 14 with an adjustable outlet section.
The electromagnetic system is similar to the 80-1 type coarse-grained magnetic machine.
The technical performance of the CS-1 type strong magnetic separator is as follows.
Induction roller:
Diameter 375 mm
Quantity 2 revolutions 40,45,50r/min
Processing capacity (related to selected minerals and particle size): 6~l0t/h
Magnetic field strength: up to 1.8T when the separation gap is 14mm
Transmission power: 26kW
Excitation power: 5.5kW
Cooling fan power: 0.34kW
Excitation coil allowable temperature: 130 ° C
Sorting gap: 14~28mm adjustment Maximum part weight: 1.795t
Machine weight: 14.8t
Machine dimensions (length x width x height): 3250mmx2374mmx2277mm

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