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What kinds of magnetic separators are there? Currently, there are many types of magnetic separators used at home and abroad, with different classification methods. (l) According to the magnetic source of the magnetic separator, it can be divided into permanent magnet magnetic separator and electromagnetic magnetic separator. ； (2) According to the strength of the magnetic field, it can be divided into: (1) Weak magnetic field magnetic separator, magnetic pole surface magnetic field strength H0 = 72-136 kA/m, magnetic field force HgradH = (2.5~5.0) x 1011 A2/m3. (2) Medium magnetic field magnetic separator, magnetic pole surface magnetic field strength H. =160～480kA/m ； (3) Strong magnetic field magnetic separator, magnetic field intensity H on the surface of the magnetic pole. = 480 ~ 1600 kA l meter, magnetic field force HgradH = (1.5 ~ 6.0) x 1013 A2/m3; (3) According to the medium in the selection process, it can be divided into dry magnetic separator and wet magnetic separator ； (4) According to the type of magnetic field, it can be divided into constant magnetic field, pulsating magnetic field and alternating magnetic field magnetic separator. ； (5) According to the body shape and structure, it is divided into belt magnetic separator, cylinder magnetic separator, roller magnetic separator, disk magnetic separator, ring magnetic separator, cage magnetic separator and pulley magnetic separator. Among them, they are mainly distinguished by magnetic field strength, selection medium and structural type. Weak magnetic separator is mainly used to separate strong magnetic minerals, such as magnetite, titanium magnetite and ferrosilicon. In the past, most industries used electromagnetic magnetic systems, and the body shapes were mostly cylindrical and belt-type. At present, most of them are permanent magnet magnetic system and cylindrical shape, and are widely used in wet type. In the past, dry-type strong magnetic separators with coarser particle size were mainly used in high-field magnetic separators at home and abroad to separate non-ferrous metals and rare metal minerals. In the past ten years, in order to select weakly magnetic minerals with low grade, fine particle size and complex mineral composition, various forms of wet strong magnetic separators have been developed, such as ring type, cage type and disc type, most of which are still in the experimental stage. Medium magnetic field magnetic separator is mainly used to separate partially oxidized strong magnetic ores. What is the difference between the magnetic system structure of a strong magnetic field magnetic separator and a weak magnetic field magnetic separator? The magnetic system is the main part of the magnetic separator. The performance of the magnetic separator is not only related to the magnetic material and magnetic field characteristics, but also has a great relationship with the magnetic structure. It is composed of a magnetic pole 1, a base plate 2 and a magnetic yoke 3 formed by bonding and stacking permanent magnet blocks. This is a three-pole magnetic system. The angle of the magnetic system is a. The distance between adjacent magnetic poles is L. As can be seen from the figure, the magnetic field lines starting from the N pole have to pass through a large air gap to reach the S pole. Since the magnetic resistance of the air is large, the magnetic field formed is a weak magnetic field, so it is suitable for selecting highly magnetic minerals. Figure 4-1 1 shows a closed magnetic system, which consists of magnetic pole head 1, iron core 2, coil 3, yoke 4 and working disk 5. Because the air gap between the magnetic poles is small, a strong magnetic field is easily generated. Therefore, high-field magnetic separators that select weakly magnetic minerals are designed to be closed magnetic systems. In order to further improve the magnetic field force of the closed sum magnetic system, the air gap can be narrowed to reduce the magnetic resistance. However, doing so will reduce the selection space and reduce the processing capacity of the equipment. Therefore, the magnetic field force is currently improved by improving the form of the magnetic pole pair and its geometric size, and placing a magnetic condensing medium with a high magnetic permeability between the two magnetic poles. For example, a whole induction medium with a certain shape (tooth plate, ball, column or net, etc.) is placed between the two original magnetic poles to form a magnetic circuit. What is the basic structure of the wet weak magnetic field permanent magnet drum magnetic separator and its magnetic field characteristics? The structure of this magnetic separator is shown in Figure 4-12. It is mainly composed of three main parts: cylinder 1, magnetic system 2 and box bottom 3 (trough body). The cylinder is made of 2-3mm stainless steel plate coil welding. The end cover of the cylinder is made of cast aluminum and is connected to the cylinder with stainless steel screws. Stainless steel (copper) or aluminum is used as the cylinder because these materials are non-magnetic materials and have good magnetic permeability, so that the magnetic lines of force will not form a magnetic short circuit with the cylinder. The surface of the cylinder is also covered with a layer of wear-resistant rubber or wrapped with a layer of thin copper wire as a protective layer to protect the cylinder surface from wear. At the same time, it is beneficial to the adhesion of magnetic mineral particles on the cylinder surface and strengthens the carrying effect of the cylinder on the magnetic mineral particles. The cylinder is rotated by an electric motor. The magnetic system 2 in the figure is a three-pole permanent magnet magnetic system, and there are also four-pole or multi-pole magnetic systems. The poles of the magnetic poles are arranged alternately along the rotation direction of the cylinder and are fixed during operation. When the magnetic mineral particles are attracted to the surface of the cylinder and rotate together with the cylinder, the magnetic flipping (also called magnetic stirring) phenomenon occurs due to the alternating polarity, and some non-magnetic mineral particles mechanically mixed in the magnetic mineral particles are removed, which can improve the quality of the magnetic products. Figure 4-13 shows the magnetic field characteristics of the CYT-600 The magnetic field intensity at the edge of the magnetic pole on the surface of the cylinder is higher than the magnetic field intensity at the center of the pole surface and the center between the poles. 20 mm away from the cylinder surface, except for the two outermost points of the magnetic pole, the magnetic field intensity at other points is similar. The average magnetic field strength on the cylinder surface is approximately 200 kA/m. What is the sorting process of the weak magnetic field permanent magnet drum magnetic separator? The sorting process is: (See Figure 4-12) After the slurry passes through the ore feeding box 7 to the feeding tank body 3 (bottom box), under the action of the water flow from the ore feeding water spray pipe 6, the ore particles enter the feeding area at the bottom of the box in a loose state. Due to the action of the magnetic field, the magnetic mineral particles gather together to form "magnetic clusters" or "magnetic links", which overcome mechanical forces such as gravity and move toward the magnetic poles, and are attracted to the surface of the cylinder 1. Then it rotates upward together with the cylinder. Due to the alternating polarity of the magnetic system, the ore particles undergo magnetic agitation, causing the mechanically mixed gangue to fall off, thereby improving the grade of the concentrate. The magnetic mineral particles follow the cylinder to the weakest point at the edge of the magnetic system. Under the action of the flushing water flow ejected from the ore unloading water pipe 8, it is unloaded into the concentrate tank. The non-magnetic or weakly magnetic mineral particles are discharged from the tailings hole in the bottom plate 9 into the tailings pipe under the action of the fast-flowing slurry flow in the tank. What types of permanent magnet drum magnetic separators are there? What are the characteristics of each? Permanent magnet drum type magnetic separators can be divided into three types: cocurrent flow type, counterflow type and semi-counterflow type according to the structure of the box bottom. The type of box bottom has a great influence on the selection index and operation. ； ring. (1) The feeding direction of the downstream permanent magnet cylinder magnetic separator is consistent with the rotation direction of the cylinder or the moving direction of the magnetic products, such as! As shown in Figure 4-14 and Figure 4-15a. The ore slurry is directly fed from the ore feeding box 3 to the bottom of the magnetic system of the cylinder 1. Non-magnetic ore particles and weakly magnetic ore particles are discharged from the gap between the two bottom plates at the bottom of the cylinder. The magnetic ore particles are attracted to the surface of the cylinder and rotate with the cylinder to the weaker magnetic field at the edge of the magnetic system. They are unloaded into the concentrate tank through the unloading water pipe. The downstream magnetic separator has a large processing capacity and is suitable for roughing and selecting coarse-grained (larger than 6 mm) strong magnetic materials, or for recycling heavy magnetic media, or multiple units can be connected in series. However, the separation index of this magnetic separator is greatly affected by the amount of ore fed, and the response is sensitive. When the amount of ore feed is large, magnetic ore particles are easily lost in the tailings. Therefore, it is necessary to strengthen operations and control lower slurry levels. (2) Counterflow magnetic separator, the ore feeding direction is opposite to the rotation direction of cylinder 1 or the moving direction of magnetic products (as shown in Figure 4-16 and Figure 4-15b). The slurry is directly fed from the ore feeding box 3 to the bottom of the magnetic system of circle 1. Non-magnetic ore particles and weakly magnetic ore particles are discharged from the tailings hole on the bottom plate under the left edge of the magnetic system. The magnetic ore particles are brought to the concentrate end along with the cylinder against the feeding direction and discharged into the concentrate tank. This kind of magnetic separator is suitable for roughing and sweeping operations of fine-grained strong magnetic minerals with a particle size less than 0.6 mm. This is because the tailings discharge port is far away from the ore feeding end. The separation time is longer and the recovery rate is higher. However, the concentrate discharge end is closer to the ore feeding port and the magnetic turning effect is poor, so the concentrate grade is lower. Countercurrent magnetic separators are not suitable for processing coarse-grained ores because the particle size is coarse and the ore particles are easy to deposit and block the separation space. 3. The ore feeding direction of the semi-countercurrent magnetic separator is basically the same as the magnetic field attraction direction (as shown in Figure 4-12 and Figure 4-15c). The slurry enters the separation space from the bottom of the tank. The magnetic ore particles are easily attracted to the surface of the cylinder, and along with the cylinder, they move to the weakest magnetic field at the edge of the magnetic system and are discharged into the concentrate tank. Non-magnetic mineral particles or mineral particles with very weak magnetism flow through the left edge of the magnetic system against the rotation direction of the cylinder and are discharged from the rectangular hole on the bottom plate. Therefore, the slurry level in the bottom box can be kept constant, and the gap between the bottom plate and the cylinder can be adjusted within a certain range (30-40 mm). This type of magnetic separator can obtain higher quality iron concentrate. At the same time, a better recovery rate can be obtained. Therefore, semi-countercurrent magnetic separators are widely used in production practice. It is suitable for rough selection and selection of highly magnetic minerals with fine particles less than 0.2 mm. It can work in series with multiple units to achieve multiple selections. What are the factors that affect the selection of permanent magnet drum class selection machines? There are many factors that affect the operation of the permanent magnet drum magnetic separator. In addition to the bottom box type, magnetic system structure and magnetic field characteristics, there are also magnetic system deflection angle, working gap, sorting concentration and cylinder speed, etc. If the magnetic system declination angle is inappropriate, it will significantly affect the sorting index. The so-called magnetic system declination angle is the angle between the center line of the magnetic system arc surface and the vertical line of the cylinder center. The grade of the tailings is low when the magnetic system is deviated to the rear, but when it is greatly deviated, the concentrate cannot be lifted to the concentrate end and falls off, which will increase the grade of the tailings. If the magnetic system is biased forward, the concentrate will be raised too high, the sweeping area will be shortened, and the tailings grade will also increase. Therefore, the magnetic system deflection angle should be adjusted to a moderate position. The distance between the roughly selected cylinder surface and the bottom plate of the bottom box is called the working gap. The size of the working gap will affect the sorting effect. The gap is large and the flow rate of the slurry is also large, which is beneficial to increasing the processing capacity. However, because it is far away from the cylinder surface and the magnetic field intensity is low, it will increase the grade of the tailings and reduce the metal recovery rate. On the contrary, if the working gap is small, the magnetic field force will be increased, which will reduce the concentrate grade, but the recovery rate can be higher. ‘If the working gap is too small, the flow rate of the slurry will be too fast, causing the ore particles to be carried to the tailings by the slurry flow before they can be sucked to the surface of the cylinder. This will cause the grade of the tailings to increase, and may even make it difficult to discharge the tailings, resulting in a "full tank" phenomenon. Therefore, when installing and maintaining the magnetic separator, attention should be paid to ensuring a suitable working gap. The size of the sorting concentration determines the flow rate of a certain amount of ore slurry and affects the sorting time of the ore particles. The concentration is high, the flow rate is slow, and the resistance is large. Gangue is easily included in the concentrate, which reduces the quality of the concentrate. However, due to the longer sorting time, it is beneficial to the recovery rate. Reverse depletion, if the sorting concentration is low, the concentrate grade can be higher, and the tailings grade will also increase, reducing the recovery rate. The size of the cylinder rotation speed also has an impact on the separation index. Low rotation speed will lead to low output. If the rotation speed is high, the centrifugal force on the ore particles will be large, the magnetic turning effect per unit time will increase, the concentrate grade and processing capacity will be high, and the recovery rate will decrease. In actual operation, it is important to adjust the blowing water for the ore and the flushing water for the concentrate. If the blowing water is too large and the slurry flow rate is too fast, the grade of the tailings will increase. On the contrary, if the blowing water is small, the ore particles will not be fully loosened and the sorting effect will be affected, resulting in an increase in the grade of the tailings and a decrease in the grade of the concentrate. The concentrate flushing water is mainly used to unload the concentrate from the drum skin. The size of the flushing water should be enough to ensure that the concentrate is unloaded. What are the common faults of permanent magnet drum separator? What is the reason for the deadlock? Common faults and their causes: (1) The motor of the magnetic separator is overheated and the sound is abnormal. The reason: 1) The bearing is poorly lubricated or severely worn ； 2) The fan blades fall off or are worn, 3) The switch circuit has poor contact or is disconnected and runs single-phase, 4) The voltage is overcaptured. (2) The sound of the magnetic separator is abnormal during operation, the cylinder is stuck by obstacles, and even the cylinder cannot rotate and the bottom box shakes. The reason is often that it is stuck by objects in the bottom box, and then the magnet falls off, causing the cylinder to rattle, and in severe cases, the cylinder skin will be scratched. At this time, the gun should be stopped for repairs to eliminate the old emblem.: (3) Reasons for overheating of the reducer: 1) Insufficient oil quantity or poor oil quality ； 2) The gears and worms are excessively worn or have poor meshing. ； 3) The bearing is poorly lubricated or severely worn. What matters should be paid attention to when starting, stopping and operating the magnetic separator? Things to note when driving and parking: (1) Before driving, you should check the power lines, transmission devices, lubrication systems and the surrounding conditions of the equipment to confirm that they are normal and clear of obstacles before driving. ； (2) The equipment should be started in a certain order. Generally speaking, when driving, drive from back to front according to the process, and when parking, the opposite is true. ； (3) When driving, first open the water pipes in each part of the equipment. The ore discharge port should be smaller at first, then feed the ore, and gradually adjust to normal operation. ； (4) When all equipment is stopped, you should first contact the water pump management personnel, then stop feeding ore, and gradually close the water gate and ore discharge port. If the water door is closed without contact, the water pump may collapse. Partial parking should also be contacted in advance to determine the number of water pumps to start. The operation of the magnetic separation process is to reduce the tailings grade as much as possible while ensuring the quality of the concentrate. To this end, operators must achieve "second diligence" and "second precision". “"Second diligence" means frequent inspection and frequent contact. Frequent inspection means that during the production process, we regularly observe whether the properties of the raw ore, the concentration of grinding, the color of the pulp, the quality of the product, and the conditions of the water and equipment are normal, so that we can be aware of them and discover problems in a timely manner. Frequent contact means that we should frequently contact and exchange information between the upper and lower processes, so as to grasp the overall situation of the work process. “"Second accuracy" means accurate judgment and correct adjustment. That is to say, on the basis of "second diligence", we can accurately judge changes in ore properties and other process factors, and adjust the process in a timely and accurate manner. What is the basic structure of the magnetic dehydration tank and its application range? Magnetic dehydration tanks can be divided into permanent magnet dehydration tanks and electromagnetic dehydration tanks according to different magnetic sources. The structure of the permanent magnet type dehydrated plant is shown in Figure 4-17. It is mainly composed of a box body, an ore feeding device, a water supply device and a magnetic system. The structure of the electromagnetic dewatering tank is shown in Figure 4-18. It mainly consists of a tank body, a cross-shaped Jun core, a coil set on the iron core and an iron hollow cylinder. How to operate the permanent magnet dewatering tank? What are the common faults? The operation of the permanent magnet dewatering tank is mainly to adjust the rising water volume and the size of the ore discharge port. In order to obtain better sorting indicators for the dewatering tank, special attention should be paid to the impact of rising water flow on its work. There are two ways to feed rising water:: Lower water supply and upper water supply. No matter which water supply method is adopted, it must be ensured that the slurry in the tank is stable and does not turn over. The function of the rising water flow is to flush out the fine-grained gangue and slime contained in the slurry. The force acting on the magnetic mineral particles (magnetic force + gravity) should be greater than the impulse of the rising water flow, and the impulse of the rising water flow must be greater than the mechanical force (mainly gravity force) acting on the non-magnetic mineral particles. Therefore the size of the rising flow must be appropriate. When the rising water flow is too large, magnetic fine particles are easy to enter the overflow, causing the phenomenon of turning over and "blackening", which will increase the grade of the tailings and cause large metal losses. If the rising water flow is small, the non-magnetic mineral particles mixed in the concentrate will not be easily flushed out, resulting in a lower concentrate grade. When the rising water flow is constant, if the discharge port is too large, the discharge concentration of the concentrate will be reduced, and the concentrate will be easily mixed with mud, thereby reducing the quality of the concentrate. On the contrary, if the ore discharge opening is too small or too small, the sorting index will also deteriorate. In order to stabilize the operation and obtain better sorting indicators, the appropriate ore discharge port and rising water volume must be determined according to the nature of the ore and the amount of ore fed, so as to ensure that there is no blockage, no discharge, and no turning over. It should be pointed out that adjusting the rising water volume of the dewatering tank is essentially to adjust the thickness of the tailings layer, control the tailings grade, and ensure the recovery rate. The adjustment of the ore discharge port is mainly to control the discharge concentration and ensure the quality of the concentrate. It can be seen that the quality of the dewatering tank operation has a very important impact on the sorting indicators. Therefore, it is necessary to create stable working conditions for the dewatering tank, such as uniform ore feeding, appropriate fineness, and all parts of the dewatering tank in normal condition. Permanent magnet dewatering tank often fails: The ore discharge weight falls off, causing the ore to not be discharged, the groove surface to be wrinkled, and the water cap to wear or fall off. When these problems are discovered, the vehicle should be stopped for maintenance immediately.