Magnetic force balance structure of compensation tank for single-tank reciprocating superconducting high-gradient magnetic separator

Abstract

The present invention discloses a magnetic force balance structure for a compensation tank of a single-tank reciprocating superconducting high-gradient magnetic separator, which includes a long compensation tank and a short compensation tank arranged on both sides of a separation tank; a number of ferromagnetic long rods are arranged in both compensation tanks; the lengths of the two compensation tanks are set such that when the central plane of the separation tank coincides with the central plane of the superconducting magnetic system, the ferromagnetic long rods in the compensation tanks on both sides extend beyond the ferromagnetic shielding end faces of the superconducting magnetic system; the arrangement mode of the ferromagnetic long rods in any cross section of the compensation tank is that the ferromagnetic long rods are distributed in concentric circles with the axis of the compensation tank as the center of the circle, and the number of concentric circles is greater than or equal to 2, and the number of ferromagnetic long rods on each concentric circle is a multiple of 2 and is evenly distributed along the circumferential direction. The present invention enables the peak value of the combined magnetic force received when the series structure formed by the compensation tank and the separation tank is moved into and out of the superconducting magnetic system to be easily adjusted to a sufficiently low level.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-gradient magnetic separators, and particularly relates to a magnetic force balance structure for a compensation tank of a single-tank reciprocating superconducting high-gradient magnetic separator. Background Art

[0002] As is well known, the magnetic force exerted on magnetic ore particles in a magnetic field is proportional to the product of the magnetic field strength and the magnetic field gradient. High-gradient magnetic separators utilize the magnetic field concentrating ability of soft ferromagnetic materials under a magnetic field to generate a high magnetic field gradient, thereby enhancing the capture ability of magnetic ore particles in pulp. The emergence of high-gradient magnetic separators has extended the particle size and magnetic permeability of magnetic ore particles that can be magnetically separated down to the fine particle and weakly magnetic range, greatly expanding the application scope of magnetic separators. Soft ferromagnetic materials are made into the forms of rods, wires, and meshes, and are often referred to as magnetic field concentrating media in the field of high-gradient magnetic separation technology. They can further increase the local magnetic field gradient by reducing the wire diameter or sharpening the cross-sectional shape, thereby enhancing the ability to capture ore particles.

[0003] Due to limitations in current density and the cooling conditions of conductors, the magnetic systems using room-temperature conductive materials such as copper and aluminum have to rely on magnetic poles made of ferromagnetic materials to increase the magnetic field strength in the magnetic force separation region. Due to the saturation effect of ferromagnetic materials and economic reasons, the magnetic field strength is limited to below 2 Tesla. Since the electric power consumed by a normal-conducting coil is proportional to the square of the magnetic field, as the magnetic field increases, more and more electrical energy is consumed on the resistance of the normal-conducting conductor, and the proportion of electrical energy used to generate the magnetic field becomes lower and lower, resulting in poorer economy of the magnetic system. Therefore, in practical applications, there are few high-gradient magnetic separators with a background magnetic field exceeding 1.2 Tesla. After nearly 30 years of development, the performance of high-gradient magnetic separators has been greatly explored, and there has been no substantial improvement for a long time.

[0004] In 1999, the US patent (US005868257) of Carpco Inc. was authorized, disclosing a reciprocating superconducting high-gradient magnetic separator. Due to the zero-resistance property under low-temperature conditions, superconducting conductors allow a current density 10 to 100 times that of normal conductors with almost no heat generation. Superconducting magnetic systems no longer require magnetic poles to increase the magnetic field strength, so the magnetic field strength in the magnetic separation region can easily be increased to above 2 Tesla and still be economical at 5 Tesla. Also for economic reasons, the time for the superconducting coil to increase or decrease the magnetic field often takes several hours, while that of a normal conducting coil can be controlled within 10 seconds. Then for the solution where the magnetic concentrating medium region is fixed - capturing magnetic ore particles by the magnetic concentrating medium under magnetic field conditions and flushing the magnetic ore particles away from the magnetic concentrating medium under non-magnetic field conditions - the superconducting high-gradient magnetic separator would have extremely low industrial application value. Therefore, the superconducting high-gradient magnetic separator in the above patent adopted a completely different solution: the magnetic field strength of the superconducting magnetic system remains unchanged, and the capture and separation of magnetic ore particles are respectively achieved by moving the magnetic system into and out of the separation tank where the magnetic concentrating medium is located. Since the separation tank moves reciprocally periodically, the magnetic separator is called a reciprocating superconducting high-gradient magnetic separator. After it was introduced to the market as a product, it was immediately applied in the kaolin purification industry in the field of non-metallic mineral separation. Compared with the normal conducting high-gradient magnetic separator, in addition to the advantage of the pulp treatment capacity of the magnetic concentrating medium per unit volume, it has an irreplaceable effect on the production of kaolin with greater impurity removal difficulty or higher quality requirements.

[0005] It takes a considerable magnetic force to move the separation tank with the magnetic medium out of the magnetic system. For an industrial superconducting magnetic separator, this force can reach several tons. In the early products of Carpco, a hydraulic device was used to move the separation tank into and out of the magnetic system. However, on the one hand, the hydraulic device increased the complexity of the magnetic separator, and on the other hand, very strict strength requirements and service life requirements were put forward for the low-leakage heat support inside the superconducting magnet. Therefore, the patent mentioned in US Patent No. US005868257 gives a magnetic force balance solution by adding a compensation tank. In the basic structure of a reciprocating superconducting high-gradient magnetic separator, the magnet is a cylindrical superconducting coil or coil group operating at low temperature. It is driven by a power supply, encapsulated in a vacuum vessel and surrounded by a ferromagnetic shield. The basic principle of the magnetic force balance solution is that the magnetic field gradient is the fundamental cause of the magnetic force on ferromagnetic materials. By adding a magnetic force compensation tank, when the separation tank moves the magnetic medium into and out of the magnetic system, the force acting on the ferromagnetic material in the magnetic field attenuation area on the left side of the magnet is equal in magnitude and opposite in direction to the force acting on the ferromagnetic material in the magnetic field attenuation area on the right side of the magnet, and the resultant magnetic force on the separation tank and the compensation tank is zero. Thus, after adding the compensation tank, on the one hand, the hydraulic device is no longer needed, and a simpler linear drive mechanism can be adopted; on the other hand, the reaction forces of the ferromagnetic materials in the separation tank and the compensation tank on the magnet reach balance inside the coil, and no additional strength requirements are added to the low-leakage heat support.

[0006] More specifically, the magnetic force balance solution adopted in US Patent No. US005868257 is that the soft ferromagnetic material in the compensation tank has the same magnetization characteristics and the same mass distribution as the magnetic medium in the separation tank, that is, the same material, coarser specifications, and the same filling form. In order to avoid damage and magnetic degradation caused by material fatigue of the soft ferromagnetic material under the action of the magnetic force, potting materials such as epoxy resin are used in the compensation tank as the support and fixation method for the soft ferromagnetic material.

[0007] However, the magnetic balance solution of US Patent No. US005868257, which uses the same material and has the same mass distribution, has the following disadvantages: 1. Steel wool with excellent magnetic aggregation performance and corrosion resistance is also used in the magnetic force compensation tank, making the manufacturing cost of the compensation tank expensive; 2. The filling rate of ferromagnetic materials is generally 5-6%, and the remaining 94-95% of the space needs to be filled with epoxy resin completely. This not only further increases the cost, but also increases the weight of the magnetic force compensation tank, making it necessary to use a stronger support device for support and a linear drive device with a larger power for driving. Especially when a sufficiently short moving-in and moving-out time is required to increase the mineral processing capacity per unit time, a larger power of the linear drive device is needed; 3. This structure not only requires assembling mechanical components, but also requires inserting the epoxy casting and curing processes during the assembly of mechanical components. The manufacturing process is complex, time-consuming and laborious. Moreover, once it is formed, if there are any deviations, it cannot be corrected anymore and can only be scrapped and remade, seriously increasing the manufacturing requirements and costs of the finished product.

[0008] Moreover, the distribution of the magnetic aggregation medium in the separation tank has an important influence on the arrangement in the compensation tank and the magnitude of the axial unbalanced magnetic field force. The distribution of the magnetic aggregation medium along the axis of the separation tank is discontinuous. Moreover, even in the magnetic force balance solution adopted in US Patent No. US005868257: the inside of the compensation tank has exactly the same structure, filling medium and filling method as the separation tank, there is also a discontinuous distribution of the magnetic aggregation medium in the compensation tank, making the remaining axial magnetic field force inevitable when entering and leaving the magnetic field attenuation regions on both sides of the magnet, and it can even reach several tons. Especially under the premise of prioritizing the separation process, that is, when pulp is introduced, the imbalance increases and the remaining axial magnetic field force is even greater. Therefore, people hope to further reduce the remaining axial magnetic field force. For example, under a 5 Tesla background magnetic field, the peak remaining axial magnetic field force is reduced to less than 200 kgf to reduce the driving cost of the linear drive device. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to provide a magnetic balance structure for a compensation tank of a single-tank reciprocating superconducting high-gradient magnetic separator.

[0010] The present invention is realized through the following technical solutions:

[0011] Compensation tank magnetic force balance structure for single-tank reciprocating superconducting high-gradient magnetic separator, comprising a long and a short compensation tank on both sides of a separation tank with magnetic concentrating media distributed inside and slurry inlet and outlet pipes at both ends; both compensation tanks are hollow cylinder structures with a central pipe in the middle, the outer diameter of which matches the inner diameter of the superconducting magnetic system of the superconducting high-gradient magnetic separator, and the inner diameter of which matches the pipe diameter of the slurry inlet and outlet pipes at both ends of the separation tank, and the central pipe is connected to the slurry inlet and outlet pipes at both ends of the separation tank to form a slurry flow channel; several ferromagnetic long rods are arranged in both compensation tanks, the ferromagnetic long rods are parallel to the axis of the compensation tank and continuously extend from one end of the compensation tank to the other end, and the manufacturing material of the ferromagnetic long rods is a material with a saturation magnetization intensity equivalent to that of the magnetic concentrating media in the separation tank; the lengths of the two compensation tanks are set such that when the central plane of the separation tank coincides with the central plane of the superconducting magnetic system, the ferromagnetic long rods in the compensation tanks on both sides extend beyond the outer end face of the ferromagnetic shield of the superconducting magnetic system; the arrangement of the ferromagnetic long rods in any cross-section of the compensation tank is as follows: the ferromagnetic long rods are distributed in concentric circles with the axis of the compensation tank as the center, and the number of concentric circles is greater than or equal to 2, and the number of ferromagnetic long rods on each concentric circle is a multiple of 2 and evenly distributed along the circumferential direction, and when installed, the positions and numbers of the ferromagnetic long rods in the two compensation tanks correspond one by one.

[0012] During operation, the slurry enters the separation tank through the central pipe of the compensation tank on one side, and after being separated by the separation tank in the superconducting magnetic system, it flows out from the other end of the separation tank through the central pipe of the compensation tank on the other side.

[0013] According to the requirements of magnetic balance in common sense, the lengths of the compensation tanks are also set to ensure that when the separation tank flushes out ferromagnetic impurities in the magnetic concentrating media outside the superconducting magnetic system, the tank body of the longer compensation tank still penetrates through the superconducting magnetic system, that is, when the separation tank is in the magnetic field attenuation area on one side, the ferromagnetic long rods in the magnetic field attenuation area on the other side provide magnetic forces of equal magnitude.

[0014] The superconducting magnetic system includes a superconducting coil in the form of a solenoid.

[0015] Preferably, the magnetic concentrating media in the separation tank is steel wool.

[0016] The arrangement of the ferromagnetic long rods in any cross-section of the compensation tank is described as follows:

[0017] First, they are concentrically distributed with the axis of the compensation tank as the center, and the number of concentric circles is greater than or equal to 2. The concentric distribution is beneficial to ensuring that the radial components of the magnetic field forces acting on all ferromagnetic long rods are symmetrically distributed with respect to the axis of the compensation tank, so that the resultant force of the radial components of the magnetic field forces acting on all ferromagnetic long rods is close to zero. The number of concentric circles being greater than or equal to 2 is to obtain a lower residual axial magnetic field force. The magnetic field of the solenoid coil of the superconducting magnetic system varies in the diameter direction, resulting in a higher axial magnetic field force acting on the ferromagnetic long rods per unit mass on the outer concentric circles than on the inner concentric circles. Therefore, the round rods on the inner concentric circles have a higher adjustment accuracy for the peak residual axial magnetic field force than those on the outer concentric circles. When the peak residual axial magnetic field force is relatively large, a peak residual axial magnetic field force closer to zero can be obtained by combining and pulling out ferromagnetic long rods on concentric circles with different diameters.

[0018] Second, the number of ferromagnetic long rods on each concentric circle is a multiple of 2, evenly distributed along the circumferential direction, and when installed, the positions and numbers of the ferromagnetic long rods in the two compensation tanks correspond one by one, so as to ensure that the radial components of the magnetic field forces acting on all ferromagnetic long rods are symmetrically distributed with respect to the axis of the compensation tank, so that the resultant force of the radial components of the magnetic field forces acting on all ferromagnetic long rods is close to zero.

[0019] Third, the radius of the innermost concentric circle is at least 1 cm greater than the inner diameter of the magnetic concentrating medium in the separation tank, and the radius of the outermost concentric circle is at least 1 cm less than the outer diameter of the magnetic concentrating medium in the separation tank, so as to facilitate the machining of support holes corresponding to the ferromagnetic long rods on the support partition.

[0020] Preferably, the cross-sectional shape of the ferromagnetic long rod is circular or annular, so as to facilitate the rotation of the ferromagnetic long rod, because from the perspective of magnetic force balance, only the total mass per unit length and the mass distribution of the ferromagnetic long rod on the cross-section are concerned, which has nothing to do with the specific shape of the cross-section of the ferromagnetic long rod. More preferably, the cross-section of the ferromagnetic long rod is circular.

[0021] Preferably, the radius of the innermost concentric circle of the ferromagnetic long rod is at least 1 cm greater than the inner diameter of the magnetic concentrating medium in the separation tank, and the radius of the outermost concentric circle of the ferromagnetic long rod is at least 1 cm less than the outer diameter of the magnetic concentrating medium in the separation tank.

[0022] Since it is only necessary to ensure that the saturation magnetization intensity of the ferromagnetic long rods in the compensation tank is close to that of the magnetic concentrating medium in the separation tank, in addition to preferably using ferritic stainless steel of grade 430 and its derivative grades as the material of the ferromagnetic long rods, the range of manufacturing materials for the ferromagnetic long rods can also be extended to common grades of steel such as Q235 and 1Cr13, so as to save the use of high-quality steel and greatly reduce the manufacturing cost of the ferromagnetic long rods.

[0023] Preferably, the cross-sectional area of the ferromagnetic long rod is a circular area smaller than a diameter of 60 mm, so that a single long rod has an adjustment accuracy of a peak residual axial magnetic field force of less than 100 kgf. At the same time, when a single long rod is pulled out, the resultant force of the radial components of the magnetic field forces received by all ferromagnetic long rods is reduced to less than 200 kgf, in order to obtain a longer maintenance period for the support components of the series structure of the compensation tank and the separation tank.

[0024] Preferably, each compensation tank includes a cylinder body and end flanges provided at both ends of the cylinder body for supporting the ferromagnetic long rods, so as to provide a basic support structure for the ferromagnetic long rods and resist the axial and radial components of the magnetic field forces they receive.

[0025] More preferably, both the cylinder body and the end flanges are made of stainless steel with a relative magnetic permeability close to 1, which has sufficient mechanical strength and does not affect the magnetic force balance of the series structure of the compensation tank and the separation tank.

[0026] More preferably, a firm structure is formed by welding between the cylinder body of each compensation tank and the end flanges on both sides.

[0027] More preferably, the thickness of the end flange steel plates on both sides of the compensation tank is greater than the thickness of the cylinder body steel plate to obtain stronger axial support strength.

[0028] Preferably, a number of support partitions are arranged at equal intervals along the axis in each compensation tank. The support partitions are made of stainless steel with a relative magnetic permeability close to 1 and are fixedly connected to the inner wall of the compensation tank by welding; support partition holes are processed at positions corresponding to each ferromagnetic long rod to allow the ferromagnetic long rods to pass through. The support partition holes can help the ferromagnetic long rods overcome the radial components of the magnetic field forces to maintain mechanical stability in the diameter direction. More preferably, the distance between the support partitions < 0.5 m, and the number of support partitions is not less than 3.

[0029] More preferably, the diameter of the support partition holes is larger than that of the ferromagnetic long rods, with a typical value of 0.6 mm, so that the ferromagnetic long rods can easily pass through the support partition holes.

[0030] Preferably, the compensation tanks on both sides and the separation tank in the middle are connected and fixed together through intermediate components. Through this modular design, the assembly difficulty can be reduced.

[0031] More preferably, the longitudinal section of the intermediate component is U-shaped to obtain the best bending resistance performance.

[0032] Preferably, the separation tank includes a separation tank barrel body and separation tank end flanges provided at both ends of the separation tank barrel body. The front ends of the ferromagnetic long rods in the compensation tanks on both sides pass through the compensation tanks and continue to extend to the separation tank end flanges on the same side of the separation tank. More preferably, an external thread structure is machined on the surface of the front end of the ferromagnetic long rod, and a threaded blind hole is provided at a position corresponding to the front end of the ferromagnetic long rod on the separation tank end flange. The front end of the ferromagnetic long rod is fixed to the separation tank end flange by screwing into the corresponding threaded blind hole. This structure can avoid the existence of "empty areas" without ferromagnetic material distribution axially in the series structure of the compensation tank and the separation tank. These "empty areas" will result in uncompensated peak residual axial magnetic field forces.

[0033] Preferably, the tail end of the ferromagnetic long rod is machined into an external hexagon or a flat shape with two parallel sides or a slotted head, to facilitate the operation of screwing into the threaded blind hole of the separation tank end flange using auxiliary tools. More preferably, an external hexagon is preferred because it can provide the best mechanical strength.

[0034] Preferably, the tail end of the ferromagnetic long rod is fixed to the outer end flange of the compensation tank using a nut and locked with another nut to overcome the axial magnetic field resultant force that always points to the center of the magnetic system.

[0035] The method for adjusting magnetic balance in the present invention: First, determine the total amount of ferromagnetic long rods in the compensation tank - determine the initial value of the total mass of the ferromagnetic long rods in the compensation tank according to the principle of equal filling rate of the unit volume mass of the magnetic concentrating medium in the separation tank; then obtain an empirical coefficient according to the measurement result of the peak axial residual magnetic field force in the actual magnetic balance test, so that the total mass of the ferromagnetic long rods is slightly higher than the optimized value. The so-called optimized value is the total mass of the ferromagnetic long rods that makes the actual peak axial residual magnetic field force the smallest. Third, in the actual magnetic balance test, pull out a small amount of ferromagnetic long rods axially symmetrically, so that the actual peak axial residual magnetic field force gradually decreases until the minimum value, and the adjustment of magnetic balance ends. Since the ferromagnetic long rods are designed to be convenient to insert and pull out in terms of structure, it facilitates the implementation of the third step above.

[0036] The ferromagnetic long rod solution of the present invention changes the thinking habit of keeping the magnetization property and mass distribution of the compensation tank magnetic balance structure completely consistent with that of the separation tank. The specific changes involve the following aspects:

[0037] First, usually the background magnetic field of a superconducting magnetic separator is above 2 Tesla. The ferromagnetic long rods in the compensation tank and the magnetic concentrating medium in the separation tank are both in a magnetically saturated state. Therefore, it is not necessary to require the two to have the same magnetization characteristics, only to require the two to have similar saturation magnetization intensities, and a higher magnetic saturation intensity is beneficial to reducing the amount of ferromagnetic long rods used.

[0038] Second, U.S. Patent US005868257 emphasizes the same mass distribution, which essentially compensates for the magnetic force balance formed after the compensation tank and the separation tank are connected in series. As described therein, the magnetic force is mainly concentrated in the magnetic field attenuation regions on both sides of the magnet. However, the arrangement of the ferromagnetic long rods in the compensation tank is the same everywhere along the axis. When adjusting the total mass of the ferromagnetic long rods and the mass distribution within the cross-section of the tank body, when the separation tank is in one side's magnetic field attenuation region, the ferromagnetic long rods in the other side's magnetic field attenuation region provide magnetic forces of equal magnitude. That is, during the process of the series structure of the separation tank and the compensation tank entering and exiting the magnetic field, the maximum value of the axial magnetic field resultant force is controlled at a sufficiently small level. We call this maximum axial magnetic field resultant force the peak residual axial magnetic field force.

[0039] Third, since the axial unbalanced force caused by the mass matching error is proportional to the background magnetic field, it is only necessary to control the magnitude of the axial unbalanced force under the highest operating magnetic field. When the magnetic field is decreased for operation, this unbalanced force will only become smaller. Therefore, when the compensation tank is made into a scheme with ferromagnetic long rods arranged inside, during adjustment, it only needs to be adjusted under the highest operating magnetic field to ensure that the axial unbalanced force in this state is reduced to an acceptable minimum value. The actual adjustment process is as follows: Monitor the peak residual magnetic field force while increasing the magnetic field; when this force is greater than a certain set value (such as 200 kgf), adjust the total amount of ferromagnetic long rods on one side to achieve magnetic force balance with the other side; until the magnetic field reaches the highest operating value.

[0040] The beneficial effects of the present invention are:

[0041] The magnetic force balance structure of the compensation tank for a single-tank reciprocating superconducting high-gradient magnetic separator of the present invention aims to reduce the peak value of the overall residual axial magnetic field force of the series structure of the compensation tank and the separation tank, relaxes the requirements for the distribution of magnetic materials in the compensation tank, making the final magnetic force balance structure have low manufacturing cost, light weight, flexibility, convenient installation and disassembly, high adjustment accuracy, and a small peak value of the residual axial magnetic field force. Even under a 5 Tesla background magnetic field, the peak residual axial magnetic field force can be reduced to less than 200 kgf, reducing the driving cost of the linear drive device, and solving the problems of high manufacturing cost, high operating cost, difficult adjustment, and poor adaptability to different slurries of the existing magnetic force balance structure of the reciprocating superconducting high-gradient magnetic separator. It has great social and economic benefits and strong practicability. Compared with the existing magnetic force compensation tank structure, it especially has the following advantages:

[0042] 1. The materials that can be selected for the ferromagnetic long rods are diverse and can be extended to conventional soft magnetic materials. Therefore, on the premise of maintaining the magnetic balance effect, the requirements for the material are relaxed, enabling the use of soft ferromagnetic materials that are much cheaper and easier to obtain than steel wool, thus greatly reducing the manufacturing cost of the compensation tank;

[0043] 2. When the cross-section of the ferromagnetic long rod is circular, it is convenient for installation;

[0044] 3. The distribution of the ferromagnetic long rods is in multiple concentric circles, making the magnetic force adjustment very convenient. During magnetic balance adjustment, only a small number of ferromagnetic long rods need to be axially symmetrically pulled out during the actual magnetic balance test, so that the actual peak axial residual magnetic force gradually decreases until the minimum value, and the adjustment of the magnetic balance ends;

[0045] 4. The number of ferromagnetic long rods on the same circle is even, which is convenient for paired installation or paired extraction without affecting the balance of the radial magnetic force;

[0046] 5. The ferromagnetic long rods are installed from the outside to the inside along the axis, which is convenient for installation;

[0047] 6. The radial support of the ferromagnetic long rods is the support partition plate in the compensation tank. The distance between the support partition plates <0.5m. The distribution of the holes in the support partition plate is consistent with the distribution of the ferromagnetic long rods. The diameter of the holes in the support partition plate is slightly larger than the diameter of the ferromagnetic long rods, which is convenient for passing the rods;

[0048] 7. When the axial support of the ferromagnetic long rod is fixed to the end flange on the same side of the adjacent separation tank of the compensation tank through internal threads and locked with double nuts on the outside, it can well resist the axial magnetic force acting on each rod;

[0049] 8. The ferromagnetic long rod is single and continuous, passing through the outer end flange of the compensation tank and the inner end flange and extending to the end flange on the same side of the adjacent separation tank, avoiding the area without magnetic medium in the series structure of the compensation tank and the separation tank, greatly reducing the magnetic force peak value, and being convenient for installation;

[0050] 9. When the series structure composed of the compensation tank and the separation tank is moved in and out of the superconducting magnetic system, the combined magnetic force received can be reduced to a suitable level. When using a linear drive device to drive the series structure of the compensation tank and the separation tank, the driving difficulty is lower, so that on the premise of ensuring a sufficiently short moving-in and moving-out time, the load of the linear drive device is smaller, and there is no additional weight of the magnetic force compensation tank due to epoxy potting, which further reduces the driving difficulty and the manufacturing cost of the compensation tank itself;

[0051] 10. The overall structure has good stability;

[0052] 11. For different filling rates of the magnetic medium in the separation tank, because the total amount of ferromagnetic long rods is easy to adjust, the flexibility is better and the adaptability is stronger. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] For ease of explanation, the present invention is described in detail by the following specific embodiments and accompanying drawings.

[0054] Figure 1 It is a schematic diagram of the series structure of the compensation tank and the separation tank of the present invention;

[0055] Figure 2 is Figure 1 a sectional view of;

[0056] Figure 3 is Figure 1 an enlarged view of portion A in;

[0057] Figure 4 is Figure 3 an enlarged view of portion B in;

[0058] Figure 5 is Figure 3 an enlarged view of portion C in;

[0059] Figure 6 is Figure 1 a side view of;

[0060] Figure 7 is a perspective view of a ferromagnetic long rod;

[0061] Figure 8 is a front view of a ferromagnetic long rod. Detailed implementation manners

[0062] As Figures 1 - 8 shown, a magnetic force balance structure for a compensation tank of a single-tank reciprocating superconducting high-gradient magnetic separator includes a long and a short compensation tank 10 disposed on both sides of a separation tank 20 with magnetic concentrating media distributed therein and slurry inlet and outlet pipes at both ends; both compensation tanks 10 are hollow cylinder structures with a central pipe provided therein, the outer diameter of which matches the inner diameter of the superconducting magnetic system of the superconducting high-gradient magnetic separator, and the inner diameter of which matches the pipe diameter of the slurry inlet and outlet pipes at both ends of the separation tank, and the central pipe is communicated with the slurry inlet and outlet pipes at both ends of the separation tank to form a slurry flow channel 40; a plurality of ferromagnetic long rods 1 are disposed in both compensation tanks 10, the ferromagnetic long rods 1 are parallel to the axis of the compensation tank 10 and continuously extend from one end of the compensation tank 10 to the other end, and the manufacturing material of the ferromagnetic long rods 1 is a material with a saturation magnetization intensity equivalent to that of the magnetic concentrating media in the separation tank 20; the lengths of both compensation tanks 10 are set such that when the central plane of the separation tank 20 coincides with the central plane of the superconducting magnetic system, the ferromagnetic long rods 1 in the compensation tanks 10 on both sides extend beyond the outer end surface of the ferromagnetic shield of the superconducting magnetic system; the arrangement manner of the ferromagnetic long rods 1 in any cross-section of the compensation tank 10 is that the ferromagnetic long rods 1 are concentrically distributed with the axis of the compensation tank 10 as the center of the circle, and the number of concentric circles is greater than or equal to 2, and the number of ferromagnetic long rods 1 on each concentric circle is a multiple of 2 and evenly distributed along the circumferential direction, and during installation, the positions and numbers of the ferromagnetic long rods 1 in both compensation tanks 10 are in one-to-one correspondence.

[0063] During operation, the pulp enters the separation tank 20 through the central pipeline of the compensation tank 10 on one side. After being sorted in the superconducting magnetic system in the separation tank 20, it flows out from the other end of the separation tank 20 through the central pipeline of the compensation tank 10 on the other side.

[0064] According to the requirements of magnetic balance in common sense, the length setting of each compensation tank 10 also ensures that: when the separation tank flushes and demagnetizes ferromagnetic impurities in the magnetic medium outside the superconducting magnetic system, the body of the longer compensation tank still penetrates through the superconducting magnetic system, that is, when the separation tank is in the magnetic field attenuation area on one side, the ferromagnetic long rod in the magnetic field attenuation area on the other side provides magnetic force of equal magnitude.

[0065] The superconducting magnetic system includes a superconducting coil in the form of a solenoid.

[0066] The magnetic medium in the separation tank 20 is steel wool.

[0067] The cross-sectional shape of the ferromagnetic long rod 1 is circular or annular to facilitate the rotation of the ferromagnetic long rod. Because from the perspective of magnetic force balance, only the total mass per unit length and mass distribution of the ferromagnetic long rod on the cross-section are concerned, which has nothing to do with the specific shape of the cross-section of the ferromagnetic long rod. More preferably, the cross-section of the ferromagnetic long rod is circular.

[0068] The radius of the innermost concentric circle of the ferromagnetic long rod 1 is at least 1 cm greater than the inner diameter of the magnetic medium in the separation tank, and the radius of the outermost concentric circle of the ferromagnetic long rod is at least 1 cm less than the outer diameter of the magnetic medium in the separation tank.

[0069] The manufacturing material of the ferromagnetic long rod 1 is 430 ferritic stainless steel or ferritic stainless steel of its derivative grades, or common grade steels such as Q235 and 1Cr13.

[0070] The cross-sectional area of the ferromagnetic long rod 1 is less than the circular area with a diameter of 60 mm, so that the adjustment accuracy of the peak residual axial magnetic force of a single long rod is less than 100 kgf. At the same time, it also reduces the resultant force of the radial components of the magnetic forces received by all ferromagnetic long rods after a single long rod is pulled out to less than 200 kgf, in order to obtain a longer maintenance cycle for the support components of the series structure of the compensation tank and the separation tank.

[0071] Each compensation tank 10 includes a cylinder body 11 and end flanges 12 provided at both ends of the cylinder body 11 for supporting the ferromagnetic long rod 1, so as to provide a basic support structure for the ferromagnetic long rod 1 and resist the axial and radial components of the magnetic force it receives.

[0072] The cylinder body 11 and the end flanges 12 are both made of stainless steel with a relative magnetic permeability close to 1, which has sufficient high mechanical strength and does not affect the magnetic force balance of the series structure of the compensation tank 10 and the separation tank 20.

[0073] The barrel body 11 of each compensation tank 10 and the end flanges 12 on both sides form a firm structure through welding.

[0074] The thickness of the steel plates of the end flanges 12 on both sides of the compensation tank 10 is greater than that of the steel plates of the barrel body 11 to obtain stronger axial support strength.

[0075] A number of support partition plates 13 are arranged at equal intervals along the axis inside each compensation tank 10. The support partition plates 13 are made of stainless steel with a relative permeability close to 1 and are fixedly connected to the inner wall of the compensation tank 10 by welding; support partition holes are processed at positions corresponding to each ferromagnetic long rod 1 on the support partition plates 13 to allow the ferromagnetic long rods to pass through. The support partition holes can help the ferromagnetic long rods overcome the radial component of the magnetic field force to maintain mechanical stability in the diameter direction. More preferably, the distance between the support partition plates is <0.5 m, and the number of support partition plates is not less than 3.

[0076] The diameter of the support partition holes is larger than that of the ferromagnetic long rod 1, with a typical value of 0.6 mm, so that the ferromagnetic long rod can easily pass through the support partition holes.

[0077] The compensation tanks 10 on both sides and the separation tank 20 in the middle are connected and fixed together through an intermediate component 30. Through this modular design, the assembly difficulty can be reduced.

[0078] The longitudinal section of the intermediate component 30 is U-shaped to obtain the best bending resistance performance.

[0079] The separation tank 20 includes a separation tank barrel body and separation tank end flanges 21 arranged at both ends of the separation tank barrel body. The front ends of the ferromagnetic long rods 1 in the compensation tanks 10 on both sides pass through the compensation tanks 10 and continue to extend to the same-side separation tank end flanges 21 on the separation tank 20. An external thread structure 2 is processed on the surface of the front end of the ferromagnetic long rod 1, and a threaded blind hole 22 is provided at a position corresponding to the front end of the ferromagnetic long rod 1 on the separation tank end flange 21. The front end of the ferromagnetic long rod 1 is fixed to the separation tank end flange 21 by screwing into the corresponding threaded blind hole 22. This structure can avoid the existence of "empty areas" without ferromagnetic material distribution axially in the series structure of the compensation tank 10 and the separation tank 20. These "empty areas" will result in uncompensated peak residual axial magnetic field forces.

[0080] The tail end of the ferromagnetic long rod 1 is processed into an external hexagon or a flat shape with two parallel sides or a slotted head to facilitate the action of screwing into the threaded blind hole of the separation tank end flange using auxiliary tools. More preferably, an external hexagon shape is selected because it can provide the best mechanical strength.

[0081] The tail end of the ferromagnetic long rod 1 is fixed to the outer end flange 12 of the compensation tank using a nut 3 and locked with another nut to overcome the axial magnetic field resultant force that always points to the center of the magnetic system.

[0082] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be thought of without creative labor should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope defined by the claims.

Claims

1. Compensation tank magnetic force balance structure for single-tank reciprocating superconducting high-gradient magnetic separator, characterized in that: There are a long and a short compensation tank on both sides of a separation tank with a magnetic concentrating medium distributed in part of it and slurry inlet and outlet pipes at both ends. Both compensation tanks are hollow cylinder structures with a central pipe in the middle. Their outer diameter matches the inner diameter of the superconducting magnetic system of the superconducting high-gradient magnetic separator, and their inner diameter matches the pipe diameter of the slurry inlet and outlet pipes at both ends of the separation tank. And the central pipe is connected to the slurry inlet and outlet pipes at both ends of the separation tank to form a slurry flow channel. A number of ferromagnetic long rods are arranged in both compensation tanks. The ferromagnetic long rods are parallel to the axis of the compensation tank and continuously extend from one end of the compensation tank to the other end. And the manufacturing material of the ferromagnetic long rods is a material with a saturation magnetization intensity equivalent to that of the magnetic concentrating medium in the separation tank. The lengths of the two compensation tanks are set such that when the central plane of the separation tank coincides with the central plane of the superconducting magnetic system, the ferromagnetic long rods in the compensation tanks on both sides extend beyond the outer end face of the ferromagnetic shield of the superconducting magnetic system. The arrangement of the ferromagnetic long rods in any cross-section of the compensation tank is as follows: the ferromagnetic long rods are distributed in concentric circles with the axis of the compensation tank as the center, and the number of concentric circles is greater than or equal to 2. And the number of ferromagnetic long rods on each concentric circle is a multiple of 2 and evenly distributed along the circumferential direction. And during installation, the positions and numbers of the ferromagnetic long rods in the two compensation tanks correspond one by one. The cross-sectional area of the ferromagnetic long rod is a circular area smaller than a diameter of 60 mm. The radius of the innermost concentric circle of the ferromagnetic long rod is at least 1 cm larger than the inner diameter of the magnetic concentrating medium in the separation tank, and the radius of the outermost concentric circle of the ferromagnetic long rod is at least 1 cm smaller than the outer diameter of the magnetic concentrating medium in the separation tank. The separation tank includes a separation tank barrel body and separation tank end flanges provided at both ends of the separation tank barrel body. The front ends of the ferromagnetic long rods in the compensation tanks on both sides extend through the compensation tanks and continue to the same-side separation tank end flanges on the separation tank. Each compensation tank includes a barrel body and end flanges provided at both ends of the barrel body for supporting the ferromagnetic long rods. A number of support partition plates are arranged at equal intervals along the axis in each compensation tank. The support partition plates are made of stainless steel with a relative magnetic permeability close to 1 and are fixedly connected to the inner wall of the compensation tank by welding. Support partition plate holes are processed at positions corresponding to each ferromagnetic long rod on the support partition plates. The front end surface of the ferromagnetic long rod is processed with an external thread structure, and threaded blind holes are provided at positions corresponding to the front ends of the ferromagnetic long rods on the separation tank end flanges. The front end of the ferromagnetic long rod is fixed to the separation tank end flange by screwing into the corresponding threaded blind holes. The tail end of the ferromagnetic long rod is fixed to the outer end flange of the compensation tank with a nut and locked with another nut. The barrel body and the end flanges are both made of stainless steel with a relative magnetic permeability close to 1. A strong structure is formed by welding between the barrel body of each compensation tank and the end flanges on both sides. The thickness of the end flange steel plates on both sides of the compensation tank is greater than the thickness of the barrel body steel plate.

2. The magnetic force balance structure of the compensation tank for the single-tank reciprocating superconducting high-gradient magnetic separator according to claim 1, wherein The cross-sectional shape of the ferromagnetic long rod is circular or annular.

3. The magnetic force balance structure of the compensation tank for the single-tank reciprocating superconducting high-gradient magnetic separator according to claim 1, characterized in that The manufacturing materials of the ferromagnetic long rods include ferritic stainless steels such as 430 ferritic stainless steel and its derivative grades, Q235, and steel grades of 1Cr13.

4. The magnetic force balance structure of the compensation tank for the single-tank reciprocating superconducting high-gradient magnetic separator according to claim 1, wherein The compensating tanks on both sides and the separating tank in the middle are fixedly connected together through an intermediate member, and the longitudinal section of the intermediate member is U-shaped.

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