Mixing equipment for electrical grade magnesium oxide production

Abstract

The invention belongs to the technical field of magnesium oxide production, and particularly relates to mixing equipment for electrical grade magnesium oxide production, which comprises a rack, a crushing box and a mixing box, the crushing box and the mixing box are arranged on the rack, two crushing shafts are arranged in the crushing box, crushing discs with crushing flanges are mounted on the shafts in a staggered manner, and a screen plate is arranged at the bottom of a crushing chamber. An auxiliary component capable of interacting with the crushing flange is installed on the plate and is one of a pressed plate, a pressed strip or an extrusion plate. According to the design, when materials are crushed, the auxiliary component can drive the screen plate to generate shaking, high-frequency vibration or horizontal material spreading movement, powder agglomeration is broken, the screening efficiency and the anti-blocking capacity are greatly improved, and it is ensured that only powder with the qualified particle size enters the mixing box. The device realizes continuous integrated operation of crushing, screening and mixing, has the advantages of high mixing uniformity, high production efficiency, strong adaptability and the like, and is particularly suitable for high-quality production of electrical grade magnesium oxide powder.

Description

Technical Field

[0001] This invention relates to the field of magnesium oxide production technology, and more particularly to a mixing device for the production of electrical grade magnesium oxide. Background Technology

[0002] As an important inorganic insulating material, electrical grade magnesium oxide is widely used in fields such as heating elements and refractory materials. During its production process, the particle size of the raw materials and the uniformity of mixing directly affect the insulation performance, thermal conductivity and mechanical strength of the final product. Therefore, efficient and uniform mixing equipment is a key link to ensure the quality of electrical grade magnesium oxide.

[0003] Currently, in the mixing process of electrical-grade magnesium oxide production, the raw materials typically require pretreatment and crushing before being transferred to mixing equipment. This method has the following significant drawbacks: firstly, the process is fragmented, involving multiple material transfers, which easily introduces contamination and material loss; secondly, the particle size distribution of the crushed powder is uneven, and direct mixing can easily lead to agglomeration or localized unevenness. Although some equipment has integrated pretreatment, crushing, and mixing, these devices have limited shearing and dispersing effects on the powder, making it difficult to break up powder agglomerates and affecting mixing accuracy and efficiency. Therefore, corresponding improvements are needed to address this issue. Summary of the Invention

[0004] Based on the technical problems existing in the prior art, the present invention proposes a mixing device for the production of electrical grade magnesium oxide.

[0005] This invention proposes a mixing device for the production of electrical grade magnesium oxide, comprising a frame, on which a crushing box and a mixing box are sequentially arranged. The discharge port of the crushing box is connected to the inlet of the mixing box. The crushing box contains a crushing chamber, in which two crushing shafts are arranged horizontally and parallel. Each crushing shaft is fitted with multiple crushing discs, and the crushing discs on the two crushing shafts are arranged alternately. The ends of the two crushing shafts are respectively equipped with a first gear and a second gear that mesh with each other to realize the relative rotation of the two crushing shafts. The grinding chamber is also equipped with a screen plate located below the grinding disc, which is used to screen the ground material. Only materials that meet the particle size requirements can pass through the screen plate and fall into the mixing box below. The outer circumference of the grinding disc is provided with multiple annular arrays of grinding flanges. The screen plate is provided with auxiliary components that can contact the grinding flanges and crush the raw materials together.

[0006] Preferably, the auxiliary component is a pressure plate, and two pressure plates are fixed on the top surface of the screen plate and are respectively located directly below the corresponding crushing shaft. The top surface of the pressure plate is an inclined surface or a curved surface. The bottom of the screen plate frame is provided with multiple guide post fixing seats, and guide posts are fixed at the bottom of the guide post fixing seats. Multiple guide post sleeves for the guide posts to pass through are fixed on the inner wall of the crushing chamber. A first spring is sleeved on the guide post between the guide post fixing seat and the guide post sleeve.

[0007] Preferably, the auxiliary component is a pressure bar, two pressure bars are fixed on the top surface of the screen plate and are respectively located directly below the corresponding crushing shaft. The pressure bar forms an inclined angle with the plane of the screen plate. The pressure bar is elastic. The screen plate is fixed in the crushing chamber.

[0008] Preferably, the auxiliary component is an extrusion plate, and two extrusion plates are located on the top surface of the screen plate and directly below the corresponding crushing shaft. There is a gap between the extrusion plate and the screen plate. The side of the extrusion plate that contacts the tip of the crushing flange is a vertical surface, and the bottom surface of the extrusion plate is an inclined surface. The screen plate is fixed in the crushing chamber. Multiple guide rods are fixed on both sides of the screen plate. The inner end of the guide rod passes through the guide rod sleeve at the top of the extrusion plate. A second spring is sleeved on the guide rod between the screen plate frame and the guide rod sleeve.

[0009] Preferably, the cross-sectional shape of the crushing flange on the crushing disc is triangular, trapezoidal, or arc-shaped.

[0010] Preferably, the aperture diameter of the screen plate is replaceable.

[0011] Preferably, the mixing tank is provided with multiple layers of stirring paddles, and the stirring paddles of different layers have different inclination angles or shapes.

[0012] Preferably, a negative pressure suction device is connected to the discharge pipe.

[0013] Preferably, the power system of the crushing chamber includes a drive motor, a gearbox, and a distribution box fixed on the frame. A first pulley and a second pulley are respectively installed on the output shaft of the drive motor and the input shaft of the gearbox. The first pulley and the second pulley are connected by a synchronous belt. The output shaft of the gearbox is connected to the end of one of the crushing shafts, thereby transmitting power to the two crushing shafts, driving the crushing disc to rotate relative to each other, and shearing and crushing the raw materials fed into the crushing chamber.

[0014] Preferably, a stirring motor is fixed to the side wall of the mixing box, the output shaft of the stirring motor is connected to a stirring shaft extending into the mixing box, and a stirring paddle is installed on the stirring shaft for fully mixing the powder falling into the mixing box. The bottom of the mixing box is provided with a discharge pipe and equipped with a control valve.

[0015] Compared with the prior art, the present invention provides a mixing device for the production of electrical grade magnesium oxide, which has the following beneficial effects: 1. This invention integrates the crushing box and the mixing box into one unit, and sets up a screen plate with auxiliary components in the crushing box, realizing continuous operation of crushing, screening and mixing of materials. The material can complete the whole process from coarse crushing, fine crushing, screening to uniform mixing with a single feeding, reducing material transfer links, improving production efficiency, and reducing the risk of cross-contamination and energy consumption.

[0016] 2. This invention, by setting three different types of auxiliary components (pressure plate, pressure strip, and extrusion plate) on the screen plate, and working in conjunction with the crushing flange on the crushing disc, not only enhances the secondary crushing effect of the material and ensures uniform particle size of the output, but more importantly, it can effectively drive the screen plate to produce shaking, high-frequency vibration, or horizontal spreading motion, which greatly prevents screen hole clogging and improves screening efficiency and continuity. It is particularly suitable for processing powder materials such as magnesium oxide that are easy to absorb moisture and agglomerate.

[0017] 3. The crushing mechanism of this invention adopts a dual-shaft belt with interlaced disc design, combined with gear meshing transmission, forming a highly efficient shearing and extrusion crushing zone with high crushing efficiency. At the same time, the design of the auxiliary components and the screen plate allows coarse materials that do not meet the particle size requirements to be continuously retained in the crushing chamber for further crushing until they pass through the screen, ensuring the consistency of the particle size of the material that finally enters the mixing box, laying the foundation for high-quality mixing in the future. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a cross-sectional structural diagram of the present invention; Figure 3 This is a schematic diagram of the internal structure of the pulverizing chamber of the present invention; Figure 4 This is a schematic diagram of the movement between the crushing disc and the pressure plate of the present invention; Figure 5 This is a schematic diagram of the installation structure between the pressure bar and the screen plate of the present invention; Figure 6 This is a schematic diagram illustrating the movement between the crushing disc and the pressure bar according to the present invention; Figure 7 This is a partial schematic diagram of the installation structure between the extrusion plate and the screen plate of the present invention; Figure 8 This is a schematic diagram of the movement between the crushing disc and the extrusion plate of the present invention.

[0019] In the diagram: 1. Frame; 2. Crushing box; 201. Crushing shaft; 202. Crushing disc; 203. First gear; 204. Crushing chamber; 205. Second gear; 3. Mixing box; 301. Stirring shaft; 302. Stirring motor; 303. Stirring paddle; 304. Discharge pipe; 4. Drive motor; 5. First pulley; 6. Gearbox; 7. Synchronous belt; 8. Second pulley; 9. Screen plate; 901. Guide column fixing seat; 10. Pressure plate; 11. Guide column guide sleeve; 12. Guide column; 13. First spring; 14. Pressure bar; 15. Extrusion plate; 1501. Guide rod guide sleeve; 16. Guide rod; 17. Second spring; 18. Distribution box. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0021] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not 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 invention.

[0022] Example 1: Refer to Figures 1 to 4 This invention provides a mixing device for the production of electrical-grade magnesium oxide, comprising a robust frame 1, which is welded from structural steel and provides support for the entire device. A crushing box 2 is fixedly installed at the upper front of the frame 1, and a mixing box 3 is fixedly installed at the lower level. The bottom outlet of the crushing box 2 is connected to the top inlet of the mixing box 3 via a chute or pipe. Alternatively, the bottom outlet of the crushing box 2 can be directly connected to the top inlet of the mixing box 3 to ensure smooth material transfer.

[0023] The grinding chamber 2 contains a four-sided enclosed grinding chamber 204. Two identical grinding shafts 201 are horizontally and parallelly mounted within the grinding chamber 204, their axes on the same horizontal plane. Each grinding shaft 201 is fixedly fitted with multiple grinding discs 202 via a key connection, and the grinding discs 202 are evenly spaced along the axial direction. Crucially, the grinding discs 202 on the two grinding shafts 201 are staggered; that is, a grinding disc 202 on one shaft is located exactly in the middle of two adjacent grinding discs 202 on the other shaft. Thus, when the two shafts rotate relative to each other, a continuous shearing and compressive action surface is formed between the staggered grinding discs 202. Multiple (e.g., 4-8) annularly arrayed grinding flanges are welded to the outer circumference of each grinding disc 202. These grinding flanges can have a pointed triangular cross-section to enhance shear force.

[0024] The right end of the two crushing shafts 201 (with Figure 1 (As shown in the viewpoint) extending to the outside of the crushing chamber 2, one crushing shaft 201 has a first gear 203 directly mounted at its end, and the other crushing shaft 201 has a second gear 205 mounted at its end. The first gear 203 and the second gear 205 mesh with each other. Therefore, when one shaft is driven, the other shaft can be driven to rotate at the same speed but in the opposite direction through the gear pair, ensuring the relative movement of the crushing disc 202.

[0025] The power system is located on the right side of the frame 1. The drive motor 4 is bolted to the frame 1, and its output shaft is fitted with a first pulley 5. The reduction gearbox 6 is also fixed to the frame 1, and its input shaft is fitted with a second pulley 8. A synchronous belt 7 is fitted between the first pulley 5 and the second pulley 8 to transmit power. The output shaft of the reduction gearbox 6 is connected to the end of the crushing shaft 201, which is fitted with the first gear 203, via a coupling. When the drive motor 4 starts, the power, after being driven by the belt and reduced in speed and torque by the reduction gearbox 6, drives the two crushing shafts 201 and their crushing discs 202 to rotate at high speed relative to each other. The electrical control box 18 is mounted on the frame 1 and contains electrical components such as circuit breakers, contactors, and frequency converters, used to control the start, stop, and speed adjustment of the drive motor 4 and the stirring motor 302 of the subsequent mixing component.

[0026] Below the crushing disc 202, a movable or vibrating screen plate 9 is horizontally installed inside the crushing chamber 204. The screen plate 9 consists of a frame and a screen tensioned within the frame. The screen can be made of stainless steel woven mesh or perforated plate, and its aperture is selected according to the target particle size of the product (e.g., 80 mesh, 100 mesh, 200 mesh, etc.). In this embodiment, the screen plate 9 is installed inside the crushing chamber 204 by an elastic suspension system. Specifically, guide post fixing seats 901 are welded to the four corners of the bottom of the frame of the screen plate 9. Each guide post fixing seat 901 has a guide post 12 vertically fixed at its bottom. Guide post sleeves 11 are fixedly installed on the side wall or bottom of the crushing chamber 204. The lower end of the guide post 12 passes through the corresponding guide post sleeve 11 and can slide up and down within it. A first spring 13 is fitted on each guide post 12. The upper end of the first spring 13 rests on the bottom surface of the guide post fixing seat 901, and the lower end rests on the top surface of the guide post sleeve 11. Therefore, the screen plate 9 is elastically supported by the first spring 13 and can float up and down.

[0027] One of the core features of this embodiment is the auxiliary components provided on the screen plate 9, such as... Figure 4 As shown, the auxiliary component is a pressure plate 10. Two elongated pressure plates 10 are fixed to the top surface of the screen plate 9 by bolts, and their positions are exactly below the two crushing shafts 201, corresponding to the trajectory of the rotating crushing disc 202 above. The top surface of the pressure plate 10 (i.e., the surface in contact with the crushing flange) is machined into an inclined surface or a smooth concave surface. When the crushing disc 202 rotates, the crushing flange on it will periodically contact and roll over the inclined surface or curved surface of the pressure plate 10.

[0028] The working principle is as follows: Initial feed (magnesium oxide blocks or coarse powder) is fed into the crushing chamber 204 through the top feed inlet of the crushing box 2. The relatively rotating crushing disc 202 first coarsely crushes and shears the material. Larger particles fall onto the screen plate 9 under the influence of gravity and the movement of the crushing disc 202. When the crushing flange on the crushing disc 202 rotates to contact the pressure plate 10, the following action occurs: 1) The edge of the crushing flange and the top surface of the pressure plate 10 form a crushing pair, further crushing the material particles between the two; 2) The crushing flange applies a downward pressure to the pressure plate 10. This pressure is transmitted to the entire screen plate 9 through the pressure plate 10. The screen plate 9 moves downward a short distance against the elastic force of the first spring 13. 3) When the crushing flange passes the pressure plate 10, the downward pressure disappears, and the screen plate 9 quickly springs back to its original position under the restoring force of the first spring 13. This process repeats itself as the crushing shaft rotates, causing the screen plate 9 to vibrate continuously up and down.

[0029] This shaking has multiple benefits: First, it greatly facilitates the passage of fine powder that has reached the required particle size through the screen openings and into the mixing chamber 3 below, resulting in high screening efficiency. Second, it effectively prevents fine powder from clogging the screen openings, ensuring the continuity of screening. Third, the shaking redistributes and agitates the coarse particles remaining on the screen plate 9, making them easier for the subsequently rotating crushing disc 202 to capture and further crush. This cycle continues until all materials are crushed to a particle size that can pass through the screen.

[0030] The qualified fine powder falling into the mixing chamber 3 is uniformly mixed inside. A stirring motor 302 is installed on the side wall of the mixing chamber 3, and its output shaft is connected to a stirring shaft 301 extending into the chamber. Multiple layers of stirring paddles 303 are installed on the stirring shaft 301. The stirring motor 302 drives the stirring paddles 303 to rotate, performing three-dimensional tumbling and shearing of the powder to ensure uniform mixing. After mixing is completed, the valve on the discharge pipe 304 at the bottom of the mixing chamber 3 is opened to discharge the mixed electrical grade magnesium oxide powder.

[0031] Example 2: Refer to Figure 5 and Figure 6 The main difference between this embodiment and Embodiment 1 lies in the form of the auxiliary components provided on the screen plate 9. In this embodiment, the auxiliary component is a pressure strip 14, and the screen plate 9 is directly and rigidly fixed to the inner wall of the crushing chamber 204 through its frame, without any overall vertical movement.

[0032] The two pressure strips 14 are also fixed to the top surface of the screen plate 9 by bolts and are located directly below the crushing shaft 201. The pressure strips 14 are made of a material with a certain degree of elasticity (such as polyurethane, rubber-coated steel strips, etc.), or their installation method makes them elastic (e.g., one end is fixed and the other end is suspended or elastically supported). The pressure strips 14 form an inclined angle (e.g., 30-60 degrees) with the horizontal screen plate 9.

[0033] When the crushing flange on the crushing disc 202 rotates and contacts the inclined pressure bar 14, the crushing flange slides along the inclined surface of the pressure bar 14 and applies a downward pressure, forcing the pressure bar 14 to bend and deform downward elastically. During this process, the material is forcefully crushed between the crushing flange and the inclined surface of the pressure bar 14. The moment the crushing flange slides away from the pressure bar 14, the pressure bar 14 rapidly returns to its original position due to its own elasticity. This periodic and rapid "bending-returning" action generates high-frequency mechanical vibration on the pressure bar 14 and directly transmits it to the screen plate 9, which is rigidly connected to it, thereby causing the entire screen plate 9 to generate high-frequency micro-amplitude vibration.

[0034] This high-frequency vibration is particularly effective for sieving extremely fine, easily agglomerated magnesium oxide powder. It can very effectively break up powder agglomerates, allowing fine powder to pass through the sieve holes quickly, while almost completely eliminating the possibility of sieve clogging, resulting in higher sieving efficiency and precision.

[0035] Example 3: Refer to Figure 7 and Figure 8 This embodiment demonstrates a third type of auxiliary component. In this embodiment, the screen plate 9 is also rigidly fixed to the inner wall of the crushing chamber 204 by its frame, and the auxiliary component is an extrusion plate 15.

[0036] Two extrusion plates 15 are mounted above the top surface of the screen plate 9 via a horizontal guiding elastic mechanism. Specifically, multiple horizontal guide rods 16 are fixed upwards on both sides of the screen plate 9. A guide rod sleeve 1501 is provided at the corresponding position on the top of the extrusion plate 15. The inner end of the guide rod 16 passes through the guide rod sleeve 1501. A second spring 17 is fitted onto each guide rod 16. The outer end of the second spring 17 rests against the edge of the screen plate 9, and the inner end rests against the bottom of the guide rod sleeve 1501. In the initial state, under the action of the spring force, the extrusion plate 15 is located near the center of the screen plate 9. The extrusion plate 15 has two special surfaces: one is the side facing the rotation direction of the crushing disc 202, which is a vertical plane; the other is the bottom surface opposite the screen plate 9, which is machined into an inclined plane.

[0037] During operation, the crushing flange on the crushing disc 202 rotates and contacts the vertical side of the extrusion plate 15. Since the crushing flange moves along the circumferential tangential direction, it generates a horizontal thrust on the vertical plane. This thrust pushes the extrusion plate 15 against the elastic force of the second spring 17, along the guide rod 16 towards the side of the screen plate 9. Figure 8 The material moves horizontally from the center to the right. During the movement, the gap between the bottom inclined surface of the extrusion plate 15 and the top surface of the fixed screen plate 9 gradually decreases from the feed side (right side) to the discharge side (left side), forming a wedge-shaped crushing zone. The material on the screen plate 9, especially the coarse particles close to the extrusion plate 15, is drawn into this gradually narrowing gap and subjected to strong extrusion and grinding, thus being further crushed.

[0038] Simultaneously, the horizontal movement of the extrusion plate 15 acts like a scraper, spreading and smoothing the material on the surface of the screen plate 9 to one side. This greatly facilitates the passage of fine powder through the screen holes from the lower part of the material layer, while also exposing coarse particles for subsequent crushing. After the crushing flange passes the extrusion plate 15, the horizontal thrust disappears, and the extrusion plate 15 quickly returns to its initial position (to the left) under the restoring force of the second spring 17. During the reset process, the vertical side of the extrusion plate 15 impacts and moves the material, again spreading and loosening the material layer. This periodic horizontal reciprocating motion, combined with the wedge-shaped crushing action, not only effectively crushes the material but also greatly improves the distribution of material on the screen plate 9, significantly increasing screening efficiency and preventing local accumulation of material on the screen.

[0039] The above three embodiments can be flexibly selected or combined according to the initial characteristics of the material (such as hardness, moisture content, and particle size distribution) and the requirements of the target product. For example, for raw materials with large initial particle size and high hardness, the pressure plate structure of Embodiment 1 can be selected, and its overall vibration is beneficial for handling larger particles; for the refining of easily agglomerated ultrafine powders, the high-frequency vibration structure of Embodiment 2 can be selected; for materials that require strong extrusion crushing and good dispersion, the structure of Embodiment 3 can be selected.

[0040] Furthermore, in other preferred embodiments of the present invention, the crushing flange on the crushing disc 202 can be designed with different cross-sectional shapes as needed. For example, a trapezoidal crushing flange can provide more stable extrusion, while an arc-shaped crushing flange can reduce wear and heat generation. The screen plate 9 can be designed with a quick-change structure, facilitating the replacement of screens with different apertures according to different product particle size standards. The stirring paddle 303 in the mixing box 3 can be designed with multiple layers. The upper layer uses propeller-type blades mainly for axial conveying, while the lower layer uses turbine-type or anchor-type blades mainly for radial shearing and mixing, thereby forming a more complex flow field and achieving rapid and uniform mixing. The discharge pipe 304 can be connected to a negative pressure conveying system to achieve closed and clean conveying of the mixed powder. Both the drive motor 4 and the stirring motor 302 can be variable frequency motors, and stepless speed regulation can be achieved through the control system in the distribution box 18, thereby precisely controlling the crushing intensity and mixing time and optimizing process parameters.

[0041] In summary, this invention effectively solves the problems of uneven mixing, low efficiency, and difficulty in particle size control during the production of electrical grade magnesium oxide by integrating crushing, screening, and mixing, as well as three efficient auxiliary screening structures, and provides a continuous, efficient, uniform, and highly adaptable special mixing equipment.

[0042] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A mixing device for the production of electrical grade magnesium oxide, comprising a frame (1), wherein a crushing box (2) and a mixing box (3) are disposed on the frame (1) and are connected to each other, characterized in that: The crushing chamber (204) of the crushing box (2) is provided with two crushing shafts (201), each crushing shaft (201) is fitted with multiple crushing discs (202), and the ends of the two crushing shafts (201) are provided with a first gear (203) and a second gear (205) that mesh with each other. The crushing chamber (204) is provided with a screen plate (9) located below the crushing disc (202). The outer circumference of the crushing disc (202) is provided with a plurality of crushing flanges arranged in an annular array. The screen plate (9) is provided with auxiliary components that can contact the crushing flanges and crush the raw materials together.

2. The mixing equipment for producing electrical-grade magnesium oxide according to claim 1, characterized in that: The auxiliary component is a pressure plate (10). Two pressure plates (10) are fixed on the top surface of the screen plate (9) and are located directly below the corresponding crushing shaft (201). The top surface of the pressure plate (10) is an inclined surface or a curved surface. The bottom of the screen plate (9) frame is provided with multiple guide post fixing seats (901), and a guide post (12) is fixed at the bottom of the guide post fixing seat (901). Multiple guide post sleeves (11) for the guide post (12) to pass through are fixed on the inner wall of the crushing chamber (204). A first spring (13) is sleeved on the guide post (12) between the guide post fixing seat (901) and the guide post sleeve (11).

3. A mixing device for producing electrical-grade magnesium oxide according to claim 1, characterized in that: The auxiliary component is a pressure bar (14). Two pressure bars (14) are fixed on the top surface of the screen plate (9) and are respectively located directly below the corresponding crushing shaft (201). The pressure bar (14) forms an inclined angle with the plane of the screen plate (9). The pressure bar (14) is elastic. The screen plate (9) is fixed in the crushing chamber (204).

4. A mixing device for producing electrical-grade magnesium oxide according to claim 1, characterized in that: The auxiliary component is an extrusion plate (15). Two extrusion plates (15) are located on the top surface of the screen plate (9) and directly below the corresponding crushing shaft (201). There is a gap between the extrusion plate (15) and the screen plate (9). The side of the extrusion plate (15) that contacts the tip of the crushing flange is a vertical surface, and the bottom surface of the extrusion plate (15) is an inclined surface. The screen plate (9) is fixed inside the crushing chamber (204). Multiple guide rods (16) are fixed on both sides of the screen plate (9). The inner end of the guide rod (16) passes through the guide rod sleeve (1501) at the top of the extrusion plate (15). A second spring (17) is sleeved on the guide rod (16) between the frame of the screen plate (9) and the guide rod sleeve (1501).

5. A mixing device for producing electrical-grade magnesium oxide according to claim 1, characterized in that: The cross-sectional shape of the crushing flange on the crushing disc (202) is triangular, trapezoidal or circular arc.

6. A mixing device for producing electrical-grade magnesium oxide according to claim 1, characterized in that: The aperture diameter of the screen plate (9) can be replaced.

7. A mixing device for producing electrical-grade magnesium oxide according to claim 1, characterized in that: The mixing tank (3) has a stirring motor (302) fixed on its side wall. The output shaft of the stirring motor (302) is connected to a stirring shaft (301) that extends into the mixing tank (3). A stirring paddle (303) is installed on the stirring shaft (301). A discharge pipe (304) is provided at the bottom of the mixing tank (3).

8. A mixing device for producing electrical-grade magnesium oxide according to claim 7, characterized in that: The mixing tank (3) is provided with multiple layers of the stirring paddles (303), and the stirring paddles (303) of different layers have different inclination angles or shapes.

9. A mixing device for producing electrical-grade magnesium oxide according to claim 7, characterized in that: A negative pressure suction device is connected to the discharge pipe (304).

10. A mixing device for producing electrical-grade magnesium oxide according to claim 1, characterized in that: The power system of the crushing box (2) includes a drive motor (4), a gearbox (6) and a power distribution box (18) fixed on the frame (1). A first pulley (5) and a second pulley (8) are respectively installed on the output shaft of the drive motor (4) and the input shaft of the gearbox (6). The first pulley (5) and the second pulley (8) are connected by a synchronous belt (7). The output shaft of the gearbox (6) is connected to the end of one of the crushing shafts (201).

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