Method for optimizing magnetic field in aluminum electrolysis cell through local external compensation

Abstract

The invention discloses a method for optimizing a magnetic field in an aluminum electrolysis cell through local external compensation, and belongs to the technical field of metal aluminum electrolysis. The local external compensation mode is permanent magnet compensation, the compensation position is a position corresponding to violent fluctuation of a magnetic field of an aluminum electrolysis series tank, and directional magnetic reconnection is formed by the local external compensation device and the magnetic field in the aluminum electrolysis tank by regulating and controlling the type, size, magnetic field intensity and permanent magnet structure included angle in the local external compensation device and the position and working temperature of the external compensation device. And magnetic field fluctuation in the aluminum electrolysis cell is corrected and compensated. Magnetic field distribution in the electrolytic cell is optimized through a directional magnetic reconnection technology, the problem that large local magnetic field fluctuation in an existing electrolytic cell is difficult to stabilize is solved, and the requirement of the aluminum electrolytic cell for magnetic field stability is met. The method is especially suitable for large-scale aluminum electrolysis cells and ensures the stability of magnetic fields in the large-scale electrolysis cells.

Description

Technical Field

[0001] The invention belongs to the technical field of metal aluminum electrolysis and discloses a method for optimizing the magnetic field in an aluminum electrolysis cell by local external compensation. Background Art

[0002] The magnetic field is the key to determining the stability of the magnetic fluid in the aluminum electrolytic cell, and the stability of the magnetic fluid not only determines the operating space of the inter-electrode spacing, but also significantly affects the service life of the electrolytic cell lining. Improving the stability of the magnetic fluid is crucial to reducing the cell voltage, improving the current efficiency, and ensuring the long-term stable operation of the electrolytic cell.

[0003] At present, the magnetic field control methods of aluminum electrolytic cells include power input bus configuration, compensation bus design, cathode structure control, electrolytic cell structure design, cathode material design, etc. For example, CN201511027158.9 discloses a configuration method and structure of a cathode bus of an electrolytic cell with controllable vertical magnetic field, which divides the cathode bus passing through the aluminum outlet and flue end into three parts: the end bus power input side part, the end bus head part, and the end bus power output side part. Each part is connected by a vertical magnetic field adjustment soft bus, so that the end bus head part can move along the vertical direction and the horizontal direction as needed, realizing the dynamic adjustment of the most important end compensation bus of the aluminum electrolytic cell. The designed bus meets the needs of magnetic fluid stability operation of large aluminum electrolytic cells and improves the overall stability index of the electrolytic cell. CN200810227124.8 discloses an external busbar compensation structure for an aluminum electrolytic cell, in which external compensation busbars are respectively arranged at both ends of an existing aluminum electrolytic cell along the series current direction; the current direction in the external compensation busbar is the same as the series current direction; the external compensation busbar and the cell body busbar jointly correct and compensate for the magnetic field disturbance of the aluminum electrolytic cell, so that the magnetic field distribution and stability of the melt in the cell are easier to achieve the best. CN201010506682.5 discloses an aluminum electrolytic cell with a special-shaped cathode structure, in which the upper end of the cathode carbon block is rounded or arc-shaped along the longitudinal direction, and a transverse groove is opened on the top of the cathode carbon block. The aluminum electrolytic cell with a special-shaped cathode structure can reduce the horizontal current in the aluminum liquid and make the magnetic field distribution more uniform. CN200910010536.0 discloses an energy-saving aluminum electrolytic cell, in which the cathode carbon block is partially or entirely immersed in aluminum liquid, and most of the aluminum liquid is located below the upper surface of the cathode carbon block. The cathode carbon block blocks the flow of aluminum liquid caused by the magnetic field, improves the stability of the magnetic fluid, and realizes production under very small fluctuations in the interface between the inter-electrode aluminum liquid and the electrolyte, thereby improving the current efficiency and reducing the DC power consumption. CN201910386896.4 discloses a directional magnetic cathode steel bar for aluminum electrolysis, which uses a regional melting or directional solidification method to produce a specific distribution gradient of alloy elements in the steel bar, and the difference in the magnetic conductivity of the elements forms a magnetic field area with controllable strength, reducing the horizontal current in the cell by 20-40%, optimizing the overall magnetic field, improving the current efficiency by more than 0.5%, and reducing the power consumption of the aluminum electrolytic cell. However, the above-mentioned magnetic field control method is difficult to achieve the optimization of local abnormal magnetic fields. For example, the magnetic field in the corner of the end slot is significantly higher than that of the ordinary slot in the middle area of ​​the series electrolytic cell. As the electrolytic cell gradually becomes larger, this problem will become more prominent.

[0004] In summary, the development of a simple and efficient method for optimizing the local magnetic field of aluminum electrolytic cells is crucial to the stable operation, energy saving and consumption reduction of existing aluminum electrolytic cells and future large-scale aluminum electrolytic cells. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a method for optimizing the magnetic field in an aluminum electrolytic cell by local external compensation. A local permanent magnetic local external compensation device is placed at a position corresponding to the violent magnetic field fluctuation in the electrolytic cell. The strong magnetic field generated by the permanent magnetic external compensation device and the magnetic field in the cell are corrected and compensated for the magnetic field fluctuation in the aluminum electrolytic cell through directional magnetic reconnection, thereby optimizing the magnetic field distribution in the aluminum electrolytic cell. At the same time, the magnetic field strength, operating temperature and position of the permanent magnetic external compensation device are all adjustable, which can meet the optimization of different abnormal magnetic field parts of the aluminum electrolytic cell.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for optimizing the magnetic field in an aluminum electrolysis cell by local external compensation, wherein the local external compensation method is permanent magnet compensation, and the permanent magnet local external compensation device is placed at a position corresponding to a position where the magnetic field in the electrolysis cell fluctuates violently. The permanent magnet external compensation device generates a magnetic field with adjustable strength to correct and compensate for the magnetic field fluctuation in the aluminum electrolysis cell through directional magnetic reconnection, thereby optimizing the magnetic field distribution in the aluminum electrolysis cell and stabilizing the magnetic fluid.

[0008] Further, the permanent magnet type is an alloy permanent magnet material, a ferrite permanent magnet material or a rare earth permanent magnet material, the alloy permanent magnet material is one of aluminum nickel cobalt alloy and iron chromium cobalt alloy or a combination of two; the ferrite permanent magnet material is one of sintered ferrite, bonded ferrite and injection molded ferrite or a combination of at least two; the rare earth permanent magnet material is one of neodymium iron boron and samarium cobalt or a combination of two;

[0009] Furthermore, the length, width and height of the permanent magnet are any combination of 10-1000mm, 10-1000mm and 10-1000mm respectively;

[0010] Furthermore, the magnetic field strength of the permanent magnet in the permanent magnet external compensation device is 100-30000 Gauss;

[0011] Furthermore, the angle between the upper and lower permanent magnet structures in the permanent magnet external compensation device is 0-180°;

[0012] Furthermore, the position adjustment mode of the permanent magnet external compensation device includes one of manual mode and automatic mode or a combination of the two;

[0013] Furthermore, the operating temperature control mode of the permanent magnet external compensation device is one or a combination of at least two of air cooling, water cooling, and thermoelectric material cooling;

[0014] Furthermore, the operating temperature of the permanent magnet external compensation device is 50-350°C;

[0015] Furthermore, the magnetic field generated by the permanent magnet external compensation device optimizes the magnetic field distribution in the electrolytic cell through the directional magnetic reconnection technology, thereby solving the problem that it is difficult for existing electrolytic cells to smooth out large local magnetic field fluctuations in the cell, and meeting the requirements of aluminum electrolytic cells, especially large aluminum electrolytic cells, for magnetic field stability.

[0016] The method of optimizing the magnetic field in an aluminum electrolysis cell by local external compensation of the present invention has the following advantages:

[0017] 1. The present invention is a method for optimizing the magnetic field in an aluminum electrolysis cell by local external compensation. The local external compensation method of the present invention is permanent magnet compensation. The magnetic field generated by the permanent magnet forms a directional magnetic reconnection with the magnetic field in the aluminum electrolysis cell to correct and compensate for the magnetic field fluctuations in the aluminum electrolysis cell.

[0018] 2. The present invention is a method for optimizing the magnetic field in an aluminum electrolytic cell by local external compensation. The local external compensation device involved in the present invention is movable and can compensate for any position in the aluminum electrolytic cell where the magnetic field fluctuates violently.

[0019] 3. The present invention is a method for optimizing the magnetic field in an aluminum electrolytic cell by local external compensation. The magnetic field strength can be regulated by the permanent magnet material, permanent magnet size, and the angle between the upper and lower permanent magnet structures to achieve the optimization of the magnetic field in different local areas in the electrolytic cell.

[0020] The present invention is a method for optimizing the magnetic field in an aluminum electrolysis cell by local external compensation. Compared with the existing aluminum electrolysis cell magnetic field optimization technology, the present invention has the following beneficial effects:

[0021] The present invention is a method for optimizing the magnetic field in an aluminum electrolytic cell by local external compensation. The local external compensation method is permanent magnet compensation. The compensation position is the position corresponding to the violent magnetic field fluctuation of the aluminum electrolytic cell series. The position of the local external compensation device and the magnetic field strength are adjustable. The magnetic field generated by the external compensation device forms a directional magnetic reconnection with the magnetic field in the aluminum electrolytic cell, correcting and compensating the magnetic field fluctuation in the aluminum electrolytic cell, solving the problem that the existing electrolytic cell is difficult to smooth the large local magnetic field fluctuation in the cell, and meeting the requirements of the aluminum electrolytic cell for magnetic field stability. The invention is particularly suitable for large aluminum electrolytic cells, avoiding the complex busbar configuration of large aluminum electrolytic cells in order to optimize the local magnetic field, and ensuring the stability of the magnetic field in large aluminum electrolytic cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic structural diagram of an aluminum electrolysis cell with a permanent magnetic local external compensation device as described in the present invention.

[0023] Figure 2 This is a schematic structural diagram of an external compensation device involved in a method for optimizing the magnetic field in an aluminum electrolysis cell by local external compensation according to the present invention.

[0024] Figure 3 This is an exploded schematic diagram of the permanent magnet external compensation device described in the present invention.

[0025] Figure 4 This is a permanent magnet external compensation device in the embodiment of the present invention, wherein the angle between the upper and lower permanent magnet structures is 150 degrees, and the heat dissipation structure is a water-cooled radiator.

[0026] Figure 5 This is a permanent magnet external compensation device in an embodiment of the present invention, wherein the angle between the upper and lower permanent magnet structures is 90 degrees, and the heat dissipation structure is a fin heat sink.

[0027] Figure 6 This is a permanent magnet external compensation device in the embodiment of the present invention, wherein the angle between the upper and lower permanent magnet structures is 60 degrees, and the heat dissipation structure is a fin heat sink.

[0028] Description of reference numerals:

[0029] 1. Upper permanent magnet structure; 2. Lower permanent magnet structure; 3. Heat dissipation structure; 4. Adjustable telescopic rod; 5. Structural support rod; 11. Permanent magnet; 12. Structural frame. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but the present invention is not limited to the following embodiments.

[0031] Example 1

[0032] The present invention provides a method for optimizing the magnetic field in an aluminum electrolysis cell by local external compensation, wherein the external compensation method is permanent magnet compensation. Figure 1 As shown, the structural schematic diagram of the permanent magnet external compensation device of the present invention is as follows Figure 2 As shown, the exploded diagram of the external compensation device structure is as follows Figure 3 As shown, it includes an upper permanent magnet structure, a lower permanent magnet structure, a heat dissipation structure, an adjustable telescopic structure, and a structural support rod. The permanent magnets in the upper permanent magnet structure and the lower permanent magnet structure are samarium cobalt; the strength of the permanent magnets in the upper permanent magnet structure and the lower permanent magnet structure is 100Gs; the size of the permanent magnet is 10mm×10mm×10mm; the angle between the upper permanent magnet structure and the lower permanent magnet structure is adjusted to 0° through the adjustable telescopic structure and the structural support rod; the heat dissipation structure of the permanent magnet external compensation device is an air-cooled radiator; the operating temperature of the permanent magnet external compensation device is 350°; the position adjustment method of the permanent magnet external compensation device is manual, and the external compensation device is placed in the middle of the series of electrolytic cells in the middle of the electrolytic cell width direction.

[0033] In this embodiment, the magnetic field optimization target is a 400kA aluminum electrolytic cell of a certain enterprise. Before the optimization of the permanent magnetic external compensation device,z The maximum value is 19.63Gs, and after optimization it is 16.31Gs.

[0034] Example 2

[0035] The present invention provides a method for optimizing the magnetic field in an aluminum electrolysis cell by local external compensation, wherein the external compensation method is permanent magnet compensation. Figure 1 As shown, the structural schematic diagram of the permanent magnet external compensation device of the present invention is as follows Figure 2 As shown, the exploded diagram of the external compensation device structure is as follows Figure 3 As shown, it includes an upper permanent magnet structure, a lower permanent magnet structure, a heat dissipation structure, an adjustable telescopic structure, and a structural support rod. The permanent magnets in the upper permanent magnet structure and the lower permanent magnet structure are neodymium iron boron; the strength of the permanent magnets in the upper permanent magnet structure and the lower permanent magnet structure is 30000Gs; the size of the permanent magnet is 1000mm×1000mm×1000mm; the angle between the upper permanent magnet structure and the lower permanent magnet structure is adjusted to 180° through the adjustable telescopic structure and the structural support rod; the heat dissipation structure of the permanent magnet external compensation device is an air-cooled radiator; the operating temperature of the permanent magnet external compensation device is 250°; the position adjustment mode of the permanent magnet external compensation device is automatic, and the external compensation device is placed in the middle of the series of electrolytic cells in the middle of the length direction of the electrolytic cell.

[0036] In this embodiment, the magnetic field optimization target is a 400kA aluminum electrolytic cell of a certain enterprise. Before the optimization of the permanent magnetic external compensation device, z The maximum value is 21.14Gs, and after optimization it is 18.38Gs.

[0037] Example 3

[0038] The present invention provides a method for optimizing the magnetic field in an aluminum electrolysis cell by local external compensation, wherein the external compensation method is permanent magnet compensation. Figure 1 As shown, the structural schematic diagram of the permanent magnet external compensation device of the present invention is as follows Figure 2 As shown, the exploded diagram of the external compensation device structure is as follows Figure 3 As shown, it includes an upper permanent magnet structure, a lower permanent magnet structure, a heat dissipation structure, an adjustable telescopic and structural support rod. The permanent magnets in the upper permanent magnet structure and the lower permanent magnet structure are made of aluminum-nickel-cobalt alloy; the strength of the permanent magnets in the upper permanent magnet structure and the lower permanent magnet structure is 3000Gs; the size of the permanent magnet is 200mm×300mm×50mm; Figure 4As shown, the angle between the upper permanent magnet structure and the lower permanent magnet structure is adjusted to 150° through adjustable telescopic and structural support rods; the heat dissipation structure of the permanent magnet external compensation device is a water-cooled radiator; the operating temperature of the permanent magnet external compensation device is 50°; the position adjustment method of the permanent magnet external compensation device is manual, and the external compensation device is placed at the corner of the middle electrolytic cell of the series of electrolytic cells.

[0039] In this embodiment, the magnetic field optimization target is a 400kA aluminum electrolytic cell of a certain enterprise. Before the optimization of the permanent magnetic external compensation device, z The maximum value is 26.63Gs, and after optimization it is 8.31Gs.

[0040] Example 4

[0041] The present invention provides a method for optimizing the magnetic field in an aluminum electrolysis cell by local external compensation, wherein the external compensation method is permanent magnet compensation. Figure 1 As shown, the structural schematic diagram of the permanent magnet external compensation device of the present invention is as follows Figure 2 As shown, the exploded diagram of the external compensation device structure is as follows Figure 3 As shown, it includes an upper permanent magnet structure, a lower permanent magnet structure, a heat dissipation structure, an adjustable telescopic and structural support rod. The permanent magnets in the upper permanent magnet structure and the lower permanent magnet structure are made of iron-chromium-cobalt alloy; the strength of the permanent magnets in the upper permanent magnet structure and the lower permanent magnet structure is 5000Gs; the size of the permanent magnet is 400mm×500mm×100mm; Figure 5 As shown, the angle between the upper permanent magnet structure and the lower permanent magnet structure is adjusted to 90° through adjustable telescopic and structural support rods; the heat dissipation structure of the permanent magnet external compensation device is an air-cooled radiator; the operating temperature of the permanent magnet external compensation device is 180°; the position adjustment method of the permanent magnet external compensation device is manual, and the external compensation device is placed in the middle of the length direction of the end slot.

[0042] In this embodiment, the magnetic field optimization target is a 400kA aluminum electrolytic cell of a certain enterprise. Before the optimization of the permanent magnetic external compensation device, z The maximum value is 22.34Gs, and after optimization it is 18.50Gs.

[0043] Example 5

[0044] The present invention provides a method for optimizing the magnetic field in an aluminum electrolysis cell by local external compensation, wherein the external compensation method is permanent magnet compensation. Figure 1 As shown, the structural schematic diagram of the permanent magnet external compensation device of the present invention is as follows Figure 2 As shown, the exploded diagram of the external compensation device structure is as follows Figure 3As shown, it includes an upper permanent magnet structure, a lower permanent magnet structure, a heat dissipation structure, an adjustable telescopic structure and a structural support rod. The permanent magnets in the upper permanent magnet structure and the lower permanent magnet structure are bonded ferrites; the strength of the permanent magnets in the upper permanent magnet structure and the lower permanent magnet structure is 10000Gs; the size of the permanent magnet is 600mm×200mm×200mm; Figure 6 As shown, the angle between the upper permanent magnet structure and the lower permanent magnet structure is adjusted to 60° through adjustable telescopic and structural support rods; the heat dissipation structure of the permanent magnet external compensation device is a thermoelectric conversion device; the operating temperature of the permanent magnet external compensation device is 80°; the position adjustment method of the permanent magnet external compensation device is manual, and the external compensation device is placed in the middle of the width direction of the end slot.

[0045] In this embodiment, the magnetic field optimization target is a 400kA aluminum electrolytic cell of a certain enterprise. Before the optimization of the permanent magnetic external compensation device, z The maximum value is 22.74Gs, and after optimization it is 19.94Gs.

[0046] Example 6

[0047] The present invention provides a method for optimizing the magnetic field in an aluminum electrolysis cell by local external compensation, wherein the external compensation method is permanent magnet compensation. Figure 1 As shown, the structural schematic diagram of the permanent magnet external compensation device of the present invention is as follows Figure 2 As shown, the exploded diagram of the external compensation device structure is as follows Figure 3 As shown, it includes an upper permanent magnet structure, a lower permanent magnet structure, a heat dissipation structure, an adjustable telescopic structure, and a structural support rod. The permanent magnets in the upper permanent magnet structure and the lower permanent magnet structure are sintered ferrites; the strength of the permanent magnets in the upper permanent magnet structure and the lower permanent magnet structure is 18000Gs; the size of the permanent magnet is 300mm×100mm×50mm; the angle between the upper permanent magnet structure and the lower permanent magnet structure is adjusted to 120° through the adjustable telescopic structure and the structural support rod; the heat dissipation structure of the permanent magnet external compensation device is an air-cooled radiator; the operating temperature of the permanent magnet external compensation device is 260°; the position adjustment method of the permanent magnet external compensation device is manual, and the external compensation device is placed at the corner of the end slot.

[0048] In this embodiment, the magnetic field optimization target is a 400kA aluminum electrolytic cell of a certain enterprise. Before the optimization of the permanent magnetic external compensation device, z The maximum value is 27.63Gs, and after optimization it is 12.39Gs.

[0049] Example 7

[0050] The present invention provides a method for optimizing the magnetic field in an aluminum electrolysis cell by local external compensation, wherein the external compensation method is permanent magnet compensation. Figure 1 As shown, the structural schematic diagram of the permanent magnet external compensation device of the present invention is as follows Figure 2 As shown, the exploded diagram of the external compensation device structure is as follows Figure 3 As shown, it includes an upper permanent magnet structure, a lower permanent magnet structure, a heat dissipation structure, an adjustable telescopic structure, and a structural support rod. The permanent magnets in the upper permanent magnet structure and the lower permanent magnet structure are injection-molded ferrites; the strength of the permanent magnets in the upper permanent magnet structure and the lower permanent magnet structure is 6000Gs; the size of the permanent magnet is 200mm×300mm×80mm; the angle between the upper permanent magnet structure and the lower permanent magnet structure is adjusted to 140° through the adjustable telescopic structure and the structural support rod; the heat dissipation structure of the permanent magnet external compensation device is a thermoelectric conversion device; the operating temperature of the permanent magnet external compensation device is 60°; the position adjustment method of the permanent magnet external compensation device is automatic, and the external compensation device is placed at the corner of the end slot.

[0051] In this embodiment, the magnetic field optimization target is a 400kA aluminum electrolytic cell of a certain enterprise. Before the optimization of the permanent magnetic external compensation device, z The maximum value is 24.65Gs, and after optimization it is 7.29Gs. The compensation bus current intensity is reduced by 28.3%.

[0052] In the description of this specification, the description of reference terms such as "one embodiment", "some embodiments", "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In the description of the present application, it should be noted that the orientation or position relationship indicated by the terms "upper" and "lower" is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise clearly specified and limited, the terms "placement" and "retraction" should be understood in a broad sense, for example, it can be fixed placement, detachable placement, or integral placement; it can be mechanical retraction or electrical retraction; for ordinary technicians in this field, the specific meanings of the above terms in the present application can be understood according to the specific circumstances. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0053] The above contents are further detailed descriptions of the present invention in combination with specific implementation methods, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention.

Claims

1. A method for optimizing the magnetic field in an aluminum electrolysis cell by local external compensation, characterized in that: A permanent magnet local external compensation device is installed at a position corresponding to a violent magnetic field fluctuation in an electrolytic cell; the type of permanent magnet in the permanent magnet local external compensation device is adjustable; the size of the permanent magnet in the permanent magnet local external compensation device is adjustable; the magnetic field strength of the permanent magnet local external compensation device is adjustable; the angle between the upper and lower permanent magnet structures of the permanent magnet local external compensation device is adjustable; the position of the permanent magnet local external compensation device is adjustable; the working temperature of the permanent magnet local external compensation device is adjustable; the strong magnetic field generated by the permanent magnet local external compensation device and the magnetic field in the cell are corrected and compensated for the magnetic field fluctuation in the aluminum electrolytic cell through directional magnetic reconnection.

2. The method for optimizing the magnetic field in an aluminum electrolysis cell by local external compensation according to claim 1, characterized in that: The type of permanent magnet in the permanent magnet local external compensation device is alloy permanent magnet material, ferrite permanent magnet material or rare earth permanent magnet material. Preferably, the alloy permanent magnet material is one of aluminum-nickel-cobalt alloy and iron-chromium-cobalt alloy, or a combination of the two; Preferably, the ferrite permanent magnet material is one of sintered ferrite, bonded ferrite, injection molded ferrite, or a combination of at least two thereof; Preferably, the rare earth permanent magnet material is one of neodymium iron boron and samarium cobalt, or a combination of the two.

3. A method for optimizing the magnetic field in an aluminum electrolysis cell by local external compensation according to claim 1 or 2, characterized in that: The permanent magnet in the external compensation device has a length of 10-1000mm, a width of 10-1000mm, and a height of 10-1000mm. Preferably, the length, width and height of the permanent magnet are any combination of 10-1000 mm, 10-1000 mm and 10-1000 mm respectively.

4. A method for optimizing the magnetic field in an aluminum electrolysis cell by local external compensation according to any one of claims 1 to 3, characterized in that: The magnetic field strength of the permanent magnet in the external compensation device is 100-30000 Gauss.

5. A method for optimizing the magnetic field in an aluminum electrolysis cell by local external compensation according to any one of claims 1 to 4, characterized in that: The included angles of the upper and lower permanent magnetic structures in the external compensation device are 0-180°.

6. A method for optimizing the magnetic field in an aluminum electrolysis cell by local external compensation according to any one of claims 1 to 5, characterized in that: The position of the external compensation device can be adjusted; Preferably, the position adjustment method of the external compensation device includes manual method, automatic method or a combination of the two.

7. A method for optimizing the magnetic field in an aluminum electrolysis cell by local external compensation according to any one of claims 1 to 6, characterized in that: The working temperature of the external compensation device is 50-350℃; Preferably, the working temperature control mode of the external compensation device is one of air cooling, water cooling, and thermoelectric material cooling, or a combination of at least two of them.

8. A method for optimizing the magnetic field in an aluminum electrolysis cell by local external compensation according to any one of claims 1 to 7, characterized in that: The permanent magnet local external compensation device is placed at a position corresponding to the violent magnetic field fluctuation. The strong magnetic field generated by the permanent magnet local external compensation device and the magnetic field in the slot correct and compensate the magnetic field fluctuation in the aluminum electrolysis cell through directional magnetic reconnection, thereby optimizing the magnetic field distribution in the aluminum electrolysis cell.

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