An alumina settling tank

Abstract

This utility model relates to the technical field of alumina production equipment. It provides an alumina settling tank, which includes a base. A barrel frame is fixedly connected to the top of the base, and a cylinder is fixedly connected to the inner circumference of the barrel frame. A control computing console is fixedly connected to the top of the base, and a density detection device is installed on the top of the cylinder. This utility model also includes a settling tank rake device, which includes a motor, a pinion, a support shaft, and an external gear ring. An output main shaft is fixedly connected to the top of the external gear ring, and the circumference of the output main shaft passes through and is slidably connected to the bottom of the cylinder. A rake arm is fixedly connected to the circumference of the output main shaft. Through the above technical solution, the problems of lack of real-time density monitoring, poor rake machine operation stability, and easy leakage in key parts in the existing alumina settling process are solved.

Description

Technical Field

[0001] This utility model relates to the technical field of alumina production equipment, specifically to an alumina settling tank. Background Technology

[0002] In the alumina production process, especially the Bayer process, solid-liquid separation is one of the core steps. The alumina settling tank, as a key piece of equipment, is mainly used to treat the dissolved sodium aluminate slurry. Through gravity settling, the supernatant of the sodium aluminate solution is separated from the underflow of solid impurities such as red mud, providing pure sodium aluminate raw materials for subsequent decomposition and calcination processes. At the same time, it reduces the operating load of subsequent equipment and ensures the quality of alumina products and production efficiency.

[0003] According to a disclosed settling tank (Publication No.: CN102107094, "An Alumina Settling Tank"), it includes: a cylinder, a rake inside the cylinder, an overflow port on the upper section of the cylinder wall, an underflow outlet at the bottom of the cylinder, a feed well connected inside the cylinder, and a feed pipe connected to the cylinder, the outlet of the feed pipe being tangential to the feed well, and a flocculant feed pipe connected to the feed pipe. This invention enables rapid mixing of the flocculant and slurry. The mixed slurry enters the feed well tangentially, and the slurry rotates and settles within the feed well, mixing again with the flocculant. Therefore, this invention can reduce the area of ​​the settling tank, improve settling efficiency, and increase the solids content of the underflow. Furthermore, according to the applicant's tests, the size of the settling tank can be reduced from Φ40m~5m~50m to Φ13m~16m after adopting this invention.

[0004] In the aforementioned application, the synergistic cooperation between the tangential feed pipe and the flocculant feed pipe, and the rotating mixing structure of the feed well, achieved efficient mixing of slurry and flocculant and miniaturization of the settling tank. However, it lacks real-time density detection function, cannot accurately monitor density changes during slurry settling, and is difficult to dynamically control settling parameters, which can easily lead to fluctuations in underflow solids content and affect the stability of subsequent processes. Therefore, we propose an alumina settling tank. Utility Model Content

[0005] To overcome the above-mentioned defects, this utility model provides an alumina settling tank, which solves the problems of lack of real-time density monitoring during the alumina settling process, poor stability of the rake machine operation, and easy leakage in key parts in the prior art.

[0006] According to one aspect, at least one embodiment of the present invention provides an alumina settling tank, comprising: an equipment base, a barrel frame fixedly connected to the top of the equipment base, a cylinder fixedly connected to the inner circumferential surface of the barrel frame, a control computing table fixedly connected to the top of the equipment base, and a density detection device provided on the top of the cylinder. The density detection device includes a housing support, the side of which is fixedly connected to the inner circumferential surface of the cylinder. A device housing is fixedly connected to the inner circumferential surface of the housing support. A sliding seat is slidably connected to the inner circumferential surface of the device housing. A force-receiving plate is fixedly connected to the bottom of the sliding seat. A force-receiving spring is fixedly connected to the top of the sliding seat. A fixed seat is fixedly connected to the top of the force-receiving spring. The circumferential surface of the fixed seat is fixedly connected to the inner circumferential surface of the device housing. A transmission rod is fixedly connected to the top of the sliding seat. The circumferential surface of the transmission rod passes through and is slidably connected to the top of the cylinder. A connecting plate is rotatably connected to the circumferential surface of the transmission rod. A sliding groove seat is fixedly connected to the top of the cylinder. One side of the connecting plate is slidably connected to the inside of the sliding groove seat. A connecting rod is fixedly connected to the side of the connecting plate. A travel recorder is slidably connected to the circumferential surface of the connecting rod. The side of the travel recorder is electrically connected to the side of the control console.

[0007] For example, in at least one embodiment of this utility model, an alumina settling tank is provided, which further includes: two outer shell supports are provided and arranged in a circular array along the vertical central axis of the outer shell of the device. The two outer shell supports are perpendicular to each other. The two mutually perpendicular and circularly arrayed outer shell supports can provide stable support for the outer shell of the device from different directions, disperse the liquid impact force on the outer shell of the device, and prevent the outer shell of the device from shifting inside the cylinder due to vibration or slurry flow, thereby ensuring the installation stability of the density detection device and providing a structural basis for subsequent accurate detection.

[0008] A sealing cover is fixedly connected to the bottom of the device housing, and a sealing ring is fixedly connected to the bottom of the sealing cover. The circumferential surface of the force-bearing plate is slidably connected to the top of the sealing cover. The sealing cover and the sealing ring cooperate to form a sealing structure, which can effectively prevent the alumina slurry inside the cylinder from entering the device housing, prevent solid particles in the slurry from adhering to the surface of components such as the sliding seat and the force-bearing spring, avoid component jamming or corrosion, ensure smooth sliding of the sliding seat, and maintain the sensitivity and service life of the density detection device.

[0009] The displacement trajectory of the force-bearing plate does not contact the bottom of the inner wall of the cylinder. The bottom of the inner wall of the cylinder is conical. The displacement trajectory of the force-bearing plate avoids the bottom of the inner wall of the cylinder, which can prevent the force-bearing plate from directly colliding with the settled alumina solid, and avoid wear of the force-bearing plate or distortion of the detection data due to contact obstruction.

[0010] The side of the slide seat has a limiting groove, and the circumferential surface of the connecting rod is slidably connected inside the limiting groove. The limiting groove constrains the movement of the connecting rod, ensuring that the connecting rod can only move along a preset trajectory, avoiding deviation when the connecting plate drives the connecting rod, and ensuring that the travel recorder can accurately capture the displacement changes of the connecting rod, thereby improving the accuracy and reliability of density detection data.

[0011] According to another aspect, at least one embodiment of the present invention also provides an alumina settling tank, comprising: a settling tank rake device, the settling tank rake device including a motor, the bottom of the motor being fixedly connected to the top of the equipment base, a pinion being fixedly connected to the output end of the motor, a support shaft being rotatably connected to the top of the equipment base, an external gear ring being fixedly connected to the top of the support shaft, an output main shaft being fixedly connected to the top of the external gear ring, the circumferential surface of the output main shaft penetrating and slidably connected to the bottom of the cylinder, and a rake arm being fixedly connected to the circumferential surface of the output main shaft.

[0012] For example, in at least one embodiment of this utility model, an alumina settling tank further includes: four rake arms arranged in a circumferential array along the vertical central axis of the output main shaft; the working surfaces of the rake arms are in contact with the bottom of the inner wall of the cylinder; the four circumferentially arrayed rake arms can fully cover the bottom of the inner wall of the cylinder, ensuring that the settled alumina solids are scraped off evenly, avoiding localized hardening of deposits; the design of the working surfaces of the rake arms contacting the bottom of the inner wall can thoroughly clean residual sediments, reduce dead corners in the cylinder cleaning, and improve the continuous operation capability of the settling tank.

[0013] The equipment is equipped with four motors and pinions arranged in a circular array along the vertical central axis of the base. Each of the four pinions meshes with an external gear ring. The four symmetrically distributed motors and pinions synchronously drive the external gear ring, ensuring balanced force on the output shaft and preventing shaft tilting or wear of transmission components caused by unilateral force. The combined power sources provide greater driving torque, ensuring stable operation of the rake arm when handling thicker sediments and enhancing the equipment's load capacity.

[0014] A rotating sleeve is fixedly connected to the top of the equipment base. The inner circumferential surface of the rotating sleeve is rotatably connected to the circumferential surface of the support shaft. The rotating sleeve provides stable rotational support for the support shaft, reduces radial runout when the support shaft rotates, ensures precise meshing between the outer gear ring and the pinion, reduces transmission noise and component wear, and extends the service life of the settling trough rake device.

[0015] A second sealing ring is provided on the circumferential surface of the output spindle. The top of the second sealing ring is fixedly connected to the bottom of the cylinder. The second sealing ring can enhance the sealing performance at the connection between the output spindle and the bottom of the cylinder, prevent the slurry inside the cylinder from leaking out of the gap, avoid material waste and equipment base contamination, and at the same time maintain stable internal pressure of the cylinder to ensure the normal progress of the alumina settling process.

[0016] The beneficial effects of the embodiments of this utility model are as follows: 1. In this utility model, the density detection device utilizes the buoyancy of the alumina slurry on the force plate to drive the sliding seat and transmission rod to move. The connecting plate, in conjunction with the sliding groove seat, guides the connecting rod to slide within the stroke recorder, thereby converting the density change of the slurry into a displacement signal and transmitting it to the control calculation table. This achieves non-radioactive density detection, avoiding the safety and environmental problems caused by radioactive elements, and reducing the difficulty and cost of operation. The sealing cover and sealing ring at the bottom of the device shell can effectively prevent the slurry from entering the device, preventing component jamming or corrosion, ensuring the sensitivity of density detection and the service life of the equipment, and improving detection accuracy and stability.

[0017] 2. In this utility model, by setting up four sets of circumferential array motors, small gears and external gear rings meshing and driving, the output main shaft and four sets of rake arms are driven to operate, so that the rake arms can comprehensively and evenly scrape off the alumina settled at the bottom of the inner wall of the cylinder, avoiding local deposition and hardening, and significantly improving the settling efficiency. In addition, the stable support of the rotating sleeve for the support shaft and the sealing effect of the second sealing ring on the circumferential surface of the output main shaft not only ensure the precise meshing and low wear of the transmission components, but also prevent the leakage of slurry in the cylinder, enhance the stability and sealing of the equipment operation, ensure the long-term continuous operation of the settling tank, and help improve production efficiency and product quality. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model, the accompanying drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are merely some exemplary embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the content of the exemplary embodiments of this utility model and these drawings without any creative effort.

[0019] Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is a schematic diagram of the structure of the three-dimensional density detection device and the settling tank rake device of this utility model; Figure 3 This utility model is three-dimensional Figure 2 A magnified structural diagram of part A in the middle; Figure 4 This is a partial structural schematic diagram of the three-dimensional density detection device of this utility model; Figure 5 This is a partial structural schematic diagram of the three-dimensional density detection device and the settling trough rake device of this utility model.

[0020] In the diagram: 1. Equipment base; 2. Barrel frame; 3. Barrel body; 4. Control and calculation console; 5. Density detection device; 51. Outer shell support; 52. Device outer shell; 53. Sliding seat; 54. Force plate; 55. Force spring; 56. Fixed seat; 57. Transmission rod; 58. Connecting plate; 59. Slide seat; 510. Connecting rod; 511. Travel recorder; 512. Sealing cover plate; 513. Limiting groove; 6. Settling tank rake device; 61. Motor; 62. Pinion; 63. Support shaft; 64. External gear ring; 65. Output main shaft; 66. Rake arm; 67. Rotating sleeve. Detailed Implementation

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit its scope.

[0022] To keep the drawings concise, only the parts relevant to the utility model are shown schematically in each drawing; these do not represent the actual structure of the product. Furthermore, for ease of understanding, in some drawings, only one of the components with the same structure or function is schematically shown, or only one is labeled. In this document, "a" not only means "only one," but can also mean "more than one," and "several" includes "two" and "more than two."

[0023] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0024] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0025] In the description of this embodiment, terms such as "upper," "lower," "left," and "right" are based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of description and simplification of operation, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0026] Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0027] like Figures 1-5 The present invention illustrates an alumina settling tank in one embodiment of the present invention, comprising: an equipment base 1, a barrel frame 2 fixedly connected to the top of the equipment base 1, a cylinder 3 fixedly connected to the inner circumferential surface of the barrel frame 2, a control computing table 4 fixedly connected to the top of the equipment base 1, and a density detection device 5 provided on the top of the cylinder 3. The density detection device 5 includes a housing support 51, the side of which is fixedly connected to the inner circumferential surface of the cylinder 3. A device housing 52 is fixedly connected to the inner circumferential surface of the housing support 51. A sliding seat 53 is slidably connected to the inner circumferential surface of the device housing 52. A force-receiving plate 54 is fixedly connected to the bottom of the sliding seat 53. A force-receiving spring 55 is fixedly connected to the top of the sliding seat 53. A fixing seat 56 is fixedly connected to the top of the force-receiving spring 55. The circumferential surface of the fixing seat 56 is fixedly connected to the inner circumferential surface of the device housing 52. On the circumference, a transmission rod 57 is fixedly connected to the top of the sliding seat 53. The circumferential surface of the transmission rod 57 passes through and is slidably connected to the top of the cylinder 3. A connecting plate 58 is rotatably connected to the circumferential surface of the transmission rod 57. A slide seat 59 is fixedly connected to the top of the cylinder 3. One side of the connecting plate 58 is slidably connected to the inside of the slide seat 59. A connecting rod 510 is fixedly connected to the side of the connecting plate 58. A travel recorder 511 is slidably connected to the circumferential surface of the connecting rod 510. The side of the travel recorder 511 is electrically connected to the side of the control computer console 4.

[0028] In some examples, there are two housing supports 51 arranged in a circular array along the vertical central axis of the housing 52. The two housing supports 51 are perpendicular to each other. The two perpendicular and circularly arrayed housing supports 51 can provide stable support for the housing 52 from different directions, disperse the liquid impact force on the housing 52, and prevent the housing 52 from shifting inside the cylinder 3 due to vibration or slurry flow. This ensures the installation stability of the density detection device 5 and provides a structural basis for subsequent accurate detection.

[0029] A sealing cover plate 512 is fixedly connected to the bottom of the device housing 52. A sealing ring is fixedly connected to the bottom of the sealing cover plate 512. The circumferential surface of the force plate 54 passes through and is slidably connected to the top of the sealing cover plate 512. The sealing cover plate 512 and the sealing ring form a sealing structure, which can effectively prevent the alumina slurry inside the cylinder 3 from entering the device housing 52, prevent solid particles in the slurry from adhering to the surface of components such as the sliding seat 53 and the force spring 55, avoid component jamming or corrosion, ensure smooth sliding of the sliding seat 53, and maintain the sensitivity and service life of the density detection device 5.

[0030] The displacement trajectory of the force-bearing disk 54 does not contact the bottom of the inner wall of the cylinder 3. The bottom of the inner wall of the cylinder 3 is conical. The displacement trajectory of the force-bearing disk 54 avoids the bottom of the inner wall of the cylinder 3, which can prevent the force-bearing disk 54 from directly colliding with the settled alumina solid, and avoid wear of the force-bearing disk 54 or distortion of the detection data due to contact obstruction.

[0031] A limiting groove 513 is provided on the side of the slide seat 59. The circumferential surface of the connecting rod 510 is slidably connected to the inside of the limiting groove 513. The limiting groove 513 constrains the movement of the connecting rod 510, ensuring that the connecting rod 510 can only move along the preset trajectory, avoiding deviation when the connecting plate 58 drives the connecting rod 510, and ensuring that the travel recorder 511 can accurately capture the displacement change of the connecting rod 510, thereby improving the accuracy and reliability of the density detection data.

[0032] For example, such as Figures 1-5 When the density of the alumina slurry inside the cylinder 3 changes, the buoyancy of the slurry on the force plate 54 changes accordingly. The force plate 54, under the action of buoyancy, pushes the sliding seat 53 to slide vertically inside the outer shell 52 of the device, while compressing or stretching the force spring 55. The sliding seat 53 drives the transmission rod 57 to move synchronously. The transmission rod 57 pushes the connecting plate 58 to deflect under the limit of the slide seat 59. The connecting plate 58 further drives the connecting rod 510 to slide along the limiting groove 513 of the slide seat 59. The sliding distance of the connecting rod 510 in the stroke recorder 511 is captured by the stroke recorder 511 and converted into an electrical signal, which is transmitted to the control computing console 4. The control computing console 4 analyzes and obtains the real-time density of the alumina slurry based on this signal.

[0033] like Figures 1-5 This illustration shows an alumina settling tank according to another embodiment of the present invention, comprising: a settling tank rake device 6, the settling tank rake device 6 including a motor 61, the bottom of the motor 61 being fixedly connected to the top of the equipment base 1, a pinion 62 being fixedly connected to the output end of the motor 61, a support shaft 63 being rotatably connected to the top of the equipment base 1, an external gear ring 64 being fixedly connected to the top of the support shaft 63, an output main shaft 65 being fixedly connected to the top of the external gear ring 64, the circumferential surface of the output main shaft 65 penetrating and slidably connected to the bottom of the cylinder 3, and a rake arm 66 being fixedly connected to the circumferential surface of the output main shaft 65.

[0034] In some examples, four rake arms 66 are arranged in a circular array along the vertical central axis of the output main shaft 65. The working surfaces of the rake arms 66 are in contact with the bottom of the inner wall of the cylinder 3. The four circumferentially arrayed rake arms 66 can fully cover the bottom of the inner wall of the cylinder 3, ensuring that the settled alumina solids are scraped off evenly and avoiding localized hardening of deposits. The design of the working surfaces of the rake arms 66 in contact with the bottom of the inner wall can thoroughly clean residual sediments, reduce cleaning dead corners of the cylinder 3, and improve the continuous operation capability of the settling tank.

[0035] There are four motors 61 and pinions 62 arranged in a circular array along the vertical central axis of the equipment base 1. The four pinions 62 mesh with the outer gear ring 64 respectively. The four symmetrically distributed motors 61 and pinions 62 synchronously drive the outer gear ring 64, so that the output main shaft 65 is subjected to balanced force, avoiding the main shaft tilting or wear of transmission components caused by unilateral force. The multi-power source cooperation can provide greater driving torque, ensuring that the rake arm 66 can still operate stably when handling thicker sediments, and enhancing the load capacity of the equipment.

[0036] A rotating sleeve 67 is fixedly connected to the top of the equipment base 1. The inner circumferential surface of the rotating sleeve 67 is rotatably connected to the circumferential surface of the support shaft 63. The rotating sleeve 67 provides stable rotational support for the support shaft 63, reduces the radial runout of the support shaft 63 during rotation, ensures the precise meshing of the outer gear ring 64 and the pinion 62, reduces transmission noise and component wear, and extends the service life of the settling trough rake device 6.

[0037] A second sealing ring is provided on the circumferential surface of the output spindle 65. The top of the second sealing ring is fixedly connected to the bottom of the cylinder 3. The second sealing ring can enhance the sealing performance at the connection between the output spindle 65 and the bottom of the cylinder 3, prevent the slurry inside the cylinder 3 from leaking through the gap, avoid material waste and contamination of the equipment base 1, and at the same time maintain the stable pressure inside the cylinder 3 to ensure the normal progress of the alumina settling process.

[0038] For example, such as Figures 1-5 The staff starts four motors 61. The output end of the motors 61 drives the pinion 62 to rotate. The four pinion 62 mesh synchronously with the outer gear ring 64, driving the outer gear ring 64 to rotate around the axis of the support shaft 63. The outer gear ring 64 drives the output main shaft 65 to rotate. The output main shaft 65 then drives the four sets of circumferentially arrayed rake arms 66 to make circumferential motion at the bottom of the inner wall of the cylinder 3. The working surface of the rake arms 66 contacts the bottom of the inner wall of the cylinder 3, uniformly scraping away the alumina solids settled at the bottom and gathering them towards the center, thus cleaning the settled material and ensuring that the alumina settling process is carried out continuously and efficiently.

[0039] It should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of the technical solution of this utility model, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.

Claims

1. An alumina settling tank, characterized in that, include: Equipment base (1), a barrel frame (2) is fixedly connected to the top of the equipment base (1), a cylinder (3) is fixedly connected to the inner circumference of the barrel frame (2), a control computing table (4) is fixedly connected to the top of the equipment base (1), and a density detection device (5) is provided on the top of the cylinder (3). The density detection device (5) includes a housing support (51), the side of which is fixedly connected to the inner circumferential surface of the cylinder (3). A device housing (52) is fixedly connected to the inner circumferential surface of the housing support (51). A sliding seat (53) is slidably connected to the inner circumferential surface of the device housing (52). A force-receiving plate (54) is fixedly connected to the bottom of the sliding seat (53). A force-receiving spring (55) is fixedly connected to the top of the sliding seat (53). A fixed seat (56) is fixedly connected to the top of the force-receiving spring (55). The circumferential surface of the fixed seat (56) is fixedly connected to the inner circumferential surface of the device housing (52). On the surface, a transmission rod (57) is fixedly connected to the top of the sliding seat (53). The circumferential surface of the transmission rod (57) passes through and is slidably connected to the top of the cylinder (3). A connecting plate (58) is rotatably connected to the circumferential surface of the transmission rod (57). A slide seat (59) is fixedly connected to the top of the cylinder (3). One side of the connecting plate (58) is slidably connected to the inside of the slide seat (59). A connecting rod (510) is fixedly connected to the side of the connecting plate (58). A travel recorder (511) is slidably connected to the circumferential surface of the connecting rod (510). The side of the travel recorder (511) is electrically connected to the side of the control computer console (4).

2. The alumina settling tank according to claim 1, characterized in that, The number of the outer shell support (51) is two, and they are arranged in a circular array along the vertical central axis of the device outer shell (52), with the two outer shell supports (51) perpendicular to each other.

3. The alumina settling tank according to claim 2, characterized in that, A sealing cover plate (512) is fixedly connected to the bottom of the outer casing (52) of the device, and a sealing ring is fixedly connected to the bottom of the sealing cover plate (512). The circumferential surface of the force-bearing plate (54) is slidably connected to the top of the sealing cover plate (512).

4. An alumina settling tank according to claim 3, characterized in that, The displacement trajectory of the force-bearing plate (54) does not contact the bottom of the inner wall of the cylinder (3), and the bottom of the inner wall of the cylinder (3) is conical.

5. An alumina settling tank according to claim 4, characterized in that, The side of the slide seat (59) has a limiting groove (513), and the circumferential surface of the connecting rod (510) is slidably connected to the inside of the limiting groove (513).

6. An alumina settling tank according to claim 5, characterized in that, The top of the equipment base (1) is provided with a settling trough rake device (6). The settling trough rake device (6) includes a motor (61). The bottom of the motor (61) is fixedly connected to the top of the equipment base (1). The output end of the motor (61) is fixedly connected to a pinion (62). The top of the equipment base (1) is rotatably connected to a support shaft (63). The top of the support shaft (63) is fixedly connected to an external gear ring (64). The top of the external gear ring (64) is fixedly connected to an output main shaft (65). The circumferential surface of the output main shaft (65) passes through and is slidably connected to the bottom of the cylinder (3). The circumferential surface of the output main shaft (65) is fixedly connected to a rake arm (66).

7. An alumina settling tank according to claim 6, characterized in that, The number of the rake arms (66) is set to four, and they are arranged in a circular array along the vertical central axis of the output main shaft (65). The working surface of the rake arms (66) is in contact with the bottom of the inner wall of the cylinder (3).

8. An alumina settling tank according to claim 7, characterized in that, The number of motors (61) and pinions (62) is four, and they are arranged in a circular array along the vertical central axis of the equipment base (1). The four pinions (62) mesh with the outer gear ring (64) respectively.

9. An alumina settling tank according to claim 8, characterized in that, A rotating sleeve (67) is fixedly connected to the top of the equipment base (1), and the inner circumferential surface of the rotating sleeve (67) is rotatably connected to the circumferential surface of the support shaft (63).

10. An alumina settling tank according to claim 9, characterized in that, The output spindle (65) is provided with a sealing ring II on its circumferential surface, and the top of the sealing ring II is fixedly connected to the bottom of the cylinder (3).

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