A mixing device and mixing method for the production of NdFeB magnets

Abstract

The present invention provides a mixing device and a mixing method for the production of neodymium-iron-boron magnets, belonging to the technical field of mixing devices. It includes a mixing tank body, and a detachable top cover is provided at the top of the mixing tank body. A screening component and an air-flow crushing component are provided at the top of the top cover. The screening component includes a screening box, and the screening box is provided at the top of the top cover. The air-flow crushing component includes an air-flow crushing chamber. One side of the screening box is connected to the air-flow crushing chamber. A stirring chamber is provided inside the mixing tank body, and a stirring component is provided in the stirring chamber. The stirring component includes a partition cover and two groups of spiral turning blades. The partition cover divides the stirring chamber into an inner mixing chamber, a turning chamber and a top mixing chamber. Multiple groups of communication grooves for communicating the inner mixing chamber and the turning chamber are opened at the bottom end of the partition cover. Both groups of spiral turning blades are located in the turning chamber. Through the setting of the air-flow crushing component, larger-particle materials can be crushed into fine particles. Through the setting of the stirring component, the materials can circulate in different chambers to ensure uniform mixing of the materials.

Description

Technical Field

[0001] The present invention belongs to the technical field of mixing devices, and more specifically, particularly relates to a mixing device and a mixing method for the production of neodymium iron boron magnets. Background Art

[0002] As a permanent magnet material, neodymium iron boron magnets have excellent magnetic properties. Compared with traditional ferrite magnets, neodymium iron boron magnets have higher energy product and magnetic energy product, and can generate a stronger magnetic field under the same volume. Therefore, they are widely used in fields such as electronics, electric motors, and automobiles.

[0003] The production process of neodymium iron boron magnets is complex. Among them, the mixing link, as the basis of the entire production process, needs to mix the material powders of neodymium iron boron magnets evenly according to a certain ratio. For example, the Chinese utility model patent with the patent number 201521092281.4 provides a mixing device for a neodymium iron boron magnet production line. This device, through the settings of a mixing bin, a stirring frame, an outer spiral ribbon, and an inner spiral ribbon, when in use, an outer spiral ribbon and an inner spiral ribbon for stirring are arranged in the stirring frame to perform double stirring inside and outside on the materials in the mixing bin; however, when the traditional mixing device directly mixes material powders with uneven particle sizes, it lacks effective processing ability, is difficult to ensure the uniformity of mixing, and thus affects the magnet performance. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a mixing device and a mixing method for the production of neodymium iron boron magnets to solve the technical problems in the prior art that when the traditional mixing device directly mixes material powders with uneven particle sizes, it lacks effective processing ability, is difficult to ensure the uniformity of mixing, and thus affects the magnet performance.

[0005] The purpose and efficacy of a mixing device and a mixing method for the production of neodymium iron boron magnets of the present invention are achieved by the following specific technical means:

[0006] A mixing device for the production of neodymium iron boron magnets includes a mixing tank body. A detachable top cover is arranged at the top of the mixing tank body. A screening component and an air flow pulverizing component are arranged at the top of the top cover. The screening component includes a screening box. The screening box is arranged at the top of the top cover. The air flow pulverizing component includes an air flow pulverizing bin. One side of the screening box is connected to the air flow pulverizing bin. A stirring cavity is arranged inside the mixing tank body. A stirring component is arranged inside the stirring cavity. The stirring component includes a partition cover and two groups of spiral turning blades. The partition cover divides the stirring cavity into an inner mixing cavity, a turning cavity, and a top mixing cavity. A plurality of communication grooves for communicating the inner mixing cavity and the turning cavity are opened at the bottom end of the partition cover. Both groups of spiral turning blades are located inside the turning cavity. The bottom of the mixing tank body is connected with a first discharge pipe through a first one-way valve.

[0007] According to a preferred embodiment, both the inner mixing chamber and the top of the material turning chamber communicate with the top mixing chamber. The stirring assembly further includes a concentric dual-axis motor. A first mounting seat is provided on the top cover, and the concentric dual-axis motor is provided on the top of the first mounting seat. A first connecting shaft and a second connecting shaft are arranged in the stirring chamber. A through hole is provided at the top of the first connecting shaft, and the second connecting shaft is inserted into the through hole. Mounting holes are provided on both the top cover and the first mounting seat. Two main shafts of the concentric dual-axis motor pass through the two mounting holes and are respectively connected to the first connecting shaft and the second connecting shaft. A sealing sleeve is arranged in the mounting hole on the top cover.

[0008] According to a preferred embodiment, connecting pieces are arranged on both sides of the first connecting shaft. One ends of the two connecting pieces are respectively provided with connecting frames. The bottom ends of the two connecting frames are respectively connected to the two spiral material turning blades. Both of the two spiral material turning blades are in contact with the inner wall of the mixing tank body and the outer side of the partition cover. Two scraping plates are respectively arranged on two opposite sides of the two connecting frames. Both of the two scraping plates are located in the top mixing chamber. One side of each of the two scraping plates is in contact with the inner wall of the mixing tank body. Guide covers facing the inner mixing chamber are respectively arranged at the bottom ends of the two connecting frames corresponding to the spiral material turning blades.

[0009] According to a preferred embodiment, two first connecting seats are arranged on the second connecting shaft corresponding to the top mixing chamber. Three first stirring frames are arranged in the top mixing chamber. One sides of the three first stirring frames are respectively connected to the two first connecting seats through two first connecting rods. Three first stirring plates facing the second connecting shaft are arranged in the first stirring frames. Two second connecting seats are also arranged on the second connecting shaft corresponding to the inner mixing chamber. Second stirring frames are connected to both sides of the two second connecting seats through two second connecting rods. Three second stirring plates facing the bottom of the inner mixing chamber are arranged on the second stirring frames. A pushing plate is arranged at the bottom end of the second connecting shaft corresponding to multiple communication grooves. One side of each of the two second stirring frames is in contact with the inner wall of the partition cover.

[0010] According to a preferred embodiment, the airflow pulverizing assembly further includes a blower and a dust filter. A second mounting seat is provided on the top cover, and the dust filter is connected to the top of the second mounting seat through screws. A mounting bracket is arranged on one side of the mixing tank body, and the blower is installed on the mounting bracket. A driving motor is arranged at the bottom of the blower, and one end of an air delivery pipe is connected to the top. The other end of the air delivery pipe is connected to the dust filter. One side of the dust filter is connected to the airflow pulverizing chamber through a pulverizing gas inlet pipe. An air inlet pipe connected to an external air path is arranged at the air inlet on one side of the blower. A pressure regulating valve is arranged on the air delivery pipe.

[0011] According to a preferred embodiment, a pulverizing groove is provided in the air flow pulverizing bin, the screening assembly is communicated with the pulverizing groove through a feed check valve, an air passage top plate and an air passage bottom plate are arranged in the pulverizing groove, the air passage top plate and the air passage bottom plate are connected by a jet ring, a through hole communicated with the pulverizing gas inlet pipe is opened at the top of the air passage top plate, a plurality of groups of pulverizing jet ports are opened on the peripheral side of the jet ring, a second discharge pipe is arranged at the bottom of the air flow pulverizing bin, a second check valve is arranged at the bottom end of the second discharge pipe, a feed inlet is opened at the top of the top cover, and the bottom end of the second check valve is connected with the feed inlet.

[0012] According to a preferred embodiment, the screening assembly further includes a first feed pipe and a return pipe. A third mounting seat is arranged at the top of the top cover, and the screening box is arranged on the top of the third mounting seat. A screening groove is opened at the top of the screening box, and a feed hopper is arranged at the top of the screening groove. A coarse filter plate and a fine filter plate are arranged up and down in the screening groove. A return port and a grinding port are opened on one side of the screening box corresponding to the coarse filter plate and the fine filter plate. One end of the return pipe is connected with the return port, and the other end of the return pipe is connected with an external pulverizer. One side of the grinding port is connected with the air flow pulverizing assembly through a feed check valve. An outlet is opened at the bottom end of the screening box, and the first feed pipe is arranged at the bottom of the outlet. A second feed pipe is further arranged at the top of the top cover, and the bottom end of the first feed pipe is connected with the second feed pipe.

[0013] According to a preferred embodiment, two groups of mounting blocks are arranged on the inner walls on both sides of the screening groove, the two ends of the coarse filter plate and the fine filter plate are respectively connected with the four groups of mounting blocks, two groups of first collecting covers are arranged on one side of the screening box corresponding to the return port and the grinding port, the two groups of first collecting covers are respectively connected with the feed check valve and the return pipe, a second collecting cover is installed at the bottom of the screening box corresponding to the outlet, a through groove is opened at the top of the third mounting seat corresponding to the second collecting cover, and the second collecting cover passes through the through groove and is connected with the top end of the first feed pipe.

[0014] According to a preferred embodiment, a partition plate is arranged in the screening tank. Both the coarse filter plate and the fine filter plate are located on one side of the partition plate. An installation plate is arranged on the third mounting seat, and an eccentric motor is arranged on the top of the installation plate. Both the third mounting seat and the bottom of the screening box are provided with sliding through grooves. Slidable movable rods are arranged in both groups of sliding through grooves. The bottom ends of both groups of movable rods are connected to a T-shaped plate. The main shaft of the eccentric motor is rotatably connected to the T-shaped plate. Limit seats are arranged at the bottoms of both groups of sliding through grooves. Limit grooves are arranged on both groups of movable rods. Both groups of limit seats are slidably connected to both groups of limit grooves. The top ends of both groups of movable rods are respectively connected to the coarse filter plate and the fine filter plate. On the other side of the partition plate, two groups of third aggregate covers are arranged corresponding to the return material port and the grinding port. First through holes are arranged on one side of both groups of third aggregate covers. A fourth aggregate cover is arranged at the bottom of the fine filter plate. A second through hole is arranged at the bottom of the fourth aggregate cover corresponding to the discharge port. A through groove is arranged on one side of the partition plate corresponding to the fine filter plate.

[0015] A mixing method for a mixing device used in the production of neodymium iron boron magnets includes the following steps:

[0016] Step 1: Material feeding;

[0017] Weigh various materials required according to the formula of the neodymium iron boron magnet, and pour the materials into the screening tank of the screening box through the feed hopper.

[0018] Step 2: Material screening;

[0019] The materials pass through the coarse filter plate and the fine filter plate distributed up and down in sequence. Material blocks that do not meet the particle size requirements will be intercepted by the coarse filter plate, discharged through the return material port and the return pipe, and transported to an external crusher for re-crushing treatment for subsequent reuse. Larger particle materials are intercepted by the fine filter plate and enter the air flow crushing chamber through the grinding port and the feed one-way pipe. Qualified material particles fall into the mixing tank body from the discharge port at the bottom end of the screening box through the first feed pipe and the second feed pipe.

[0020] Step 3: Air flow crushing;

[0021] Start the drive motor to drive the fan to work. External gas is inhaled into the fan through the intake pipe. After the inhaled gas is pressurized in the fan, it is transported to the dust filter through the air delivery pipe. The dust filter filters out fine impurities such as dust in the gas. The purified gas enters the air flow crushing chamber through the crushed gas intake pipe. In the air flow crushing chamber, the gas enters the jet ring between the airway top plate and the airway bottom plate, and then jets out at high speed from multiple groups of crushing jet orifices on the peripheral side. At this time, the larger particle materials entering the air flow crushing chamber from the feed one-way pipe collide and rub against each other under the impact of the high-speed air flow, and are crushed into finer particles to meet the requirements for the particle size of the materials. The crushed materials are discharged from the second discharge pipe at the bottom of the air flow crushing chamber. The second one-way valve at the bottom end of the second discharge pipe ensures that the materials can only flow downward and fall into the mixing tank body through the feed port, ready for mixing and stirring;

[0022] Step Four: Mixing and Stirring;

[0023] When all the materials enter the mixing tank body, start the concentric double-shaft motor. The two main shafts of the concentric double-shaft motor drive the first connecting shaft and the second connecting shaft to rotate respectively. When the first connecting shaft rotates, it drives two groups of spiral turning blades to rotate in the turning cavity through the connecting pieces and connecting frames on both sides, continuously turning the materials in the turning cavity upward to make them enter the top mixing cavity. At the same time, two groups of scrapers on the connecting frame rotate in the top mixing cavity. One side of the scraper contacts the inner wall of the mixing tank body, scraping off the materials on the inner wall of the top mixing cavity to make them participate in the mixing again. The guiding cover can guide the materials in the top mixing cavity to flow into the inner mixing cavity. When the second connecting shaft rotates, it drives three groups of first stirring frames in the top mixing cavity and two groups of second stirring frames in the inner mixing cavity to rotate synchronously. The three first stirring plates in the first stirring frame stir and mix the materials in the top mixing cavity. At the same time, the three first stirring plates all face the second connecting shaft, making the materials in the top mixing cavity approach the second connecting shaft and fall into the inner mixing cavity under the action of gravity; The three second stirring plates stir the materials in the inner mixing cavity. At the same time, the three second stirring plates all face the bottom of the inner mixing cavity, making the materials move towards the bottom of the inner mixing cavity. The bottom end of the second connecting shaft is connected to a pushing plate. The pushing plate rotates to push the materials at the bottom of the inner mixing cavity into the connecting groove, and makes them enter the turning cavity through the connecting groove, realizing the circulating flow of materials between different chambers and ensuring the full and uniform mixing of various materials in the mixing tank body;

[0024] Step Five: Processing of the Mixed Materials;

[0025] After the materials are mixed evenly, open the first one-way valve at the bottom of the mixing tank body, and discharge the mixed materials through the first discharge pipe.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. Through the setting of the screening component, when using the device, the material can be screened by the upper and lower distributed coarse filter plate and fine filter plate before entering the mixing tank body. The material blocks that do not meet the particle size requirements will be blocked by the coarse filter plate and sent to the external crusher through the return port for re-crushing. The larger particle materials will enter the air flow crushing component and be crushed by the high-speed air flow, solving the problem of uneven mixing of materials with large particle size differences in the traditional mixing device, making the particle size of the materials entering the mixing tank body uniform, ensuring the uniform internal composition of the magnet, and improving the stability.

[0028] 2. Through the setting of the stirring component, the concentric double-shaft motor drives the first connecting shaft and the second connecting shaft to rotate, and cooperates with multiple groups of stirring parts to operate; the first and second stirring frames stir in the top mixing chamber and the inner mixing chamber respectively. The first stirring plate and the second stirring plate on them are both angled to guide the orderly flow of the material. The pushing plate can push the material at the bottom of the inner mixing chamber into the connecting groove, so that it enters the turning chamber. Moreover, the spiral turning blades turn the material in the turning chamber and transport it from the bottom of the turning chamber to the top mixing chamber, enabling the material to circulate in different chambers and ensuring the full and uniform mixing of various materials in the mixing tank body; through the setting of two groups of scraping plates, the material on the wall surface of the top mixing chamber can be scraped off to prevent accumulation.

[0029] 3. Through the setting of the air flow crushing component, when using the device, when the larger particle materials enter the air flow crushing bin, the fan is started to input gas through the crushing gas inlet pipe. The input gas is ejected at high speed from multiple groups of crushing jet ports on the circumferential side of the jet ring. The larger particle materials collide and rub against each other under the impact of the high-speed air flow and are crushed into finer particles to meet the requirements for the particle size of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is the assembled structural schematic diagram of Embodiment 1 of the present invention;

[0031] Figure 2 is the unfolded structural schematic diagram of Embodiment 1 of the present invention;

[0032] Figure 3 is the structural schematic diagram of the stirring component after disassembly in the present invention;

[0033] Figure 4 is the structural schematic diagram of the first connecting shaft and the second connecting shaft after disassembly in the present invention;

[0034] Figure 5 is the structural schematic diagram of the second connecting shaft and the pushing plate after disassembly in the present invention;

[0035] Figure 6 is the front view of the present invention;

[0036] Figure 7 Is Figure 6 The sectional view taken along A - A in it;

[0037] Figure 8 It is the structural schematic diagram after the air - jet milling assembly in the present invention is disassembled;

[0038] Figure 9 It is the structural schematic diagram after the air - jet milling chamber in the present invention is assembled;

[0039] Figure 10 It is the structural schematic diagram after the air - jet milling chamber in the present invention is disassembled;

[0040] Figure 11 It is the structural schematic diagram after the screening assembly in the present invention is assembled;

[0041] Figure 12 It is the structural schematic diagram after the screening assembly in the present invention is disassembled;

[0042] Figure 13 It is the structural schematic diagram after the screening assembly in the second embodiment of the present invention is assembled;

[0043] Figure 14 It is the structural schematic diagram after the screening assembly in the second embodiment of the present invention is disassembled;

[0044] Figure 15 It is the step - flow chart of the mixing method of the mixing device for producing neodymium - iron - boron magnets in the present invention.

[0045] In the figure, the corresponding relationship between the component names and the drawing numbers is:

[0046] 101. Mixing tank body; 102. Top cover; 103. Feed inlet; 104. Second feed pipe; 105. First one-way valve; 106. First discharge pipe; 201. Screening box; 202. Feed one-way pipe; 203. First feed pipe; 204. Return pipe; 205. Third mounting seat; 206. Screening trough; 207. Feed hopper; 208. Coarse filter plate; 209. Fine filter plate; 210. Return port; 211. Grinding port; 213. Mounting block; 214. First collecting cover; 215. Second collecting cover; 216. Partition plate; 217. Mounting plate; 218. Eccentric motor; 219. Sliding through slot; 220. Movable rod; 221. T-shaped plate; 222. Limit seat; 223. Limit slot; 224. Third collecting cover; 225. Fourth collecting cover; 301. Air flow pulverizing chamber; 302. Blower; 303. Dust filter; 304. Second mounting seat; 305. Mounting bracket; 306. Driving motor; 307. Air delivery pipe; 308. Pulverizing gas inlet pipe; 309. Inlet pipe; 310. Pressure regulating valve; 311. Pulverizing trough; 312. Air passage top plate; 313. Air passage bottom plate; 314. Jet ring; 315. Pulverizing jet orifice; 316. Second discharge pipe; 317. Second one-way valve; 401. Partition cover; 402. Spiral turning blade; 403. Inner mixing cavity; 404. Turning cavity; 405. Top mixing cavity; 406. Concentric double-shaft motor; 407. First mounting seat; 408. First connecting shaft; 409. Second connecting shaft; 410. Mounting hole; 411. Sealing sleeve; 412. Connecting piece; 413. Connecting frame; 414. Scraper; 415. Guide cover; 416. First connecting seat; 417. First stirring frame; 418. First connecting rod; 419. First stirring plate; 420. Second connecting seat; 421. Second connecting rod; 422. Second stirring frame; 423. Second stirring plate; 424. Communication slot; 425. Pushing plate. Detailed implementation mode

[0047] The following further describes in detail the implementation mode of the present invention in conjunction with the drawings and embodiments. The following embodiments are used to illustrate the technical solutions of the present invention, but cannot be used to limit the protection scope of the present invention.

[0048] Embodiment 1: As shown in the attached Figures 1 to 15 figure:

[0049] The present invention provides a mixing device for the production of NdFeB magnets, which includes a mixing tank body 101. A detachable top cover 102 is provided at the top of the mixing tank body 101, facilitating the daily maintenance, cleaning, and overhaul of internal components of the device. A screening component and an air flow crushing component are provided at the top of the top cover 102, which are respectively responsible for screening and crushing the materials to ensure that the materials entering the mixing tank body 101 meet the quality standards and have uniform particle sizes. The screening component includes a screening box 201, which is arranged on the top of the top cover 102. The air flow crushing component includes an air flow crushing chamber 301. One side of the screening box 201 is connected to the air flow crushing chamber 301. A stirring chamber is provided inside the mixing tank body 101, and a stirring component is arranged in the stirring chamber. The stirring component includes a partition cover 401 and two groups of spiral turning blades 402. The partition cover 401 divides the stirring chamber into three different regions: an inner mixing chamber 403, a turning chamber 404, and a top mixing chamber 405. Multiple groups of connecting grooves 424 are opened at the bottom end of the partition cover 401 to connect the inner mixing chamber 403 and the turning chamber 404, enabling the materials to circulate between different chambers and preventing material accumulation or uneven mixing. The two groups of spiral turning blades 402 are both located in the turning chamber 404 and are used to convey the materials at the bottom of the turning chamber 404 to the top mixing chamber 405. The bottom of the mixing tank body 101 is connected to a first discharge pipe 106 through a first one-way valve 105. The setting of the first one-way valve 105 prevents backflow or material leakage.

[0050] Please refer to as Figure 3 And Figure 7 As shown, both the top of the inner mixing chamber 403 and the turning chamber 404 are connected to the top mixing chamber 405. The stirring component further includes a concentric double-shaft motor 406 as a driving source to provide stable power input for the stirring operation. A first mounting seat 407 is provided at the top of the top cover 102 to provide a mounting base for the concentric double-shaft motor 406. The concentric double-shaft motor 406 is arranged at the top of the first mounting seat 407 to ensure the stability of the motor during operation. A first connecting shaft 408 and a second connecting shaft 409 are arranged in the stirring chamber as power transmission components. A through hole adapted to the second connecting shaft 409 is opened at the top of the first connecting shaft 408, and the second connecting shaft 409 is rotatably arranged in the through hole. Corresponding mounting holes 410 are opened on both the top cover 102 and the first mounting seat 407 to provide a through path for the two main shafts of the concentric double-shaft motor 406. The two main shafts of the concentric double-shaft motor 406 pass through the two mounting holes 410 and are respectively connected to the first connecting shaft 408 and the second connecting shaft 409. To prevent materials from overflowing through the mounting holes 410 during the stirring process, a sealing sleeve 411 is configured in the mounting holes 410 on the top cover 102.

[0051] Please refer to as Figure 4As shown, two sets of connecting pieces 412 are symmetrically arranged on both sides of the first connecting shaft 408. One end of each set of the two sets of connecting pieces 412 is connected to a connecting frame 413 by screws. The bottoms of the two connecting frames 413 are respectively connected to the two spiral turning blades 402. When the first connecting shaft 408 rotates driven by the concentric dual-shaft motor 406, the power is sequentially transmitted to the spiral turning blades 402 through the connecting pieces 412 and the connecting frames 413, driving them to rotate. During the rotation of the two spiral turning blades 402, the materials in the turning cavity 404 are turned over and transported from the bottom of the turning cavity 404 to the top mixing cavity 405, enabling the materials to circulate in different chambers. Two sets of scraping plates 414 are respectively arranged on the corresponding two sides of the two connecting frames 413. The two scraping plates 414 are both located in the top mixing cavity 405. One side of each of the two scraping plates 414 is in contact with the inner wall of the mixing tank body 101. The two scraping plates 414 rotate synchronously with the connecting frames 413, scraping off the materials adhering to the inner wall of the top mixing cavity 405 and prompting them to return to the mixing process. At the bottom ends of the two connecting frames 413, guide covers 415 facing the inner mixing cavity 403 are respectively arranged corresponding to the spiral turning blades 402, guiding the materials turned from the turning cavity 404 to the top mixing cavity 405 to flow towards the inner mixing cavity 403, ensuring the circulating flow of the materials between different chambers and improving the mixing effect.

[0052] Please refer to Figure 5As shown, there are two groups of first connection seats 416 corresponding to the top mixing chamber 405 on the second connection shaft 409. There are three groups of first stirring frames 417 arranged in the top mixing chamber 405. There are three groups of first stirring plates 419 facing the second connection shaft 409 arranged in the first stirring frames 417. One side of the three groups of first stirring frames 417 is connected to the two groups of first connection seats 416 through two groups of first connecting rods 418 respectively. When the second connection shaft 409 rotates, it drives the three groups of first stirring frames 417 to rotate synchronously. The three groups of first stirring plates 419 in the first stirring frames 417 play a stirring function to stir the materials in the top mixing chamber 405. And the three groups of first stirring plates 419 all face the second connection shaft 409. Under the action of the first stirring plates 419, the materials gather towards the second connection shaft 409 and fall into the inner mixing chamber 403 under the action of gravity, realizing the orderly transfer of materials between the chambers; Similarly, there are two groups of second connection seats 420 corresponding to the inner mixing chamber 403 on the second connection shaft 409. Both sides of the two groups of second connection seats 420 are connected with second stirring frames 422 through two groups of second connecting rods 421. There are three groups of second stirring plates 423 facing the bottom of the inner mixing chamber 403 arranged on the second stirring frames 422, which can stir the materials in the inner mixing chamber 403 and push the materials towards the bottom at the same time. In addition, a pushing plate 425 corresponding to multiple groups of communication grooves 424 is arranged at the bottom end of the second connection shaft 409. According to the material circulation requirements, it rotates with the second connection shaft 409 to push the materials near the communication grooves 424 at the bottom of the inner mixing chamber 403 to the vicinity of the communication grooves 424, helping the materials to enter the turning chamber 404 through the communication grooves 424, making the circulation of materials between different chambers smooth, further improving the mixing uniformity of the materials. One side of the two groups of second stirring frames 422 is in contact with the inner wall of the partition cover 401, and can scrape off the materials attached to the inner wall of the partition cover 401.

[0053] Please refer to as Figure 8As shown in the figure, the air flow crushing assembly further includes a fan 302 and a dust filter 303. A second mounting seat 304 is provided at the top of the top cover 102. The dust filter 303 is connected to the top of the second mounting seat 304 by screws, providing a stable mounting position for the dust filter 303. An installation bracket 305 is provided on one side of the mixing tank body 101, and the fan 302 is installed on the installation bracket 305, providing a solid support for the fan 302; the drive motor 306 at the bottom of the fan 302 serves as a power source. After starting, it drives the fan 302 to operate. External gas is continuously sucked into the fan 302 through the intake pipe 309 on the air inlet. The sucked gas is pressurized in the fan 302 and then transported to the dust filter 303 through the air delivery pipe 307 connected to the top of the fan 302. The dust filter 303 intercepts fine impurities such as dust in the gas to ensure that the purity of the gas entering the air flow crushing chamber 301 meets the standard; the purified gas smoothly enters the air flow crushing chamber 301 through the crushing gas inlet pipe 308, providing power support for material crushing; a pressure regulating valve 310 is provided on the air delivery pipe 307. The operator can adjust the pressure regulating valve 310 according to actual production needs to control the gas pressure, and then adjust the air flow crushing intensity to adapt to the crushing requirements of different materials.

[0054] Please refer to as Figure 9 and Figure 10 As shown in the figure, a crushing groove 311 is provided in the air flow crushing chamber 301. The screening assembly is communicated with the crushing groove 311 through the feed check valve 202. An air duct top plate 312 and an air duct bottom plate 313 are provided in the crushing groove 311. The air duct top plate 312 and the air duct bottom plate 313 are connected by a jet ring 314. A through hole communicating with the crushing gas inlet pipe 308 is opened at the top of the air duct top plate 312, providing an inlet for the purified gas to enter the jet ring 314. Multiple groups of crushing jet ports 315 are opened on the peripheral side of the jet ring 314. When the gas jets out from the crushing jet ports 315 at high speed, according to the principle of gas-solid two-phase flow, a high-intensity impact environment is created in the crushing groove 311. According to the principles of collision crushing and friction wear, the material particles collide and rub against each other violently and are gradually refined to the particle size that meets the production requirements of neodymium iron boron magnets; a second discharge pipe 316 is provided at the bottom of the air flow crushing chamber 301 as the output channel for the crushed material. A second check valve 317 is provided at the bottom end of the second discharge pipe 316 to ensure that the material only flows downward; a feed inlet 103 is opened at the top of the top cover 102. The bottom end of the second check valve 317 is connected to the feed inlet 103, and the material falls into the mixing tank body 101 through the feed inlet 103 at the top of the top cover 102 to prepare for mixing.

[0055] Please refer to as Figure 11 and Figure 12As shown, the screening assembly further includes a first feed pipe 203 and a return pipe 204. A third mounting seat 205 is provided at the top of the top cover 102, and a screening box 201 is provided at the top of the third mounting seat 205. A screening groove 206 is formed at the top of the screening box 201, and a feed hopper 207 is provided at the top of the screening groove 206. The feed hopper 207 is funnel-shaped, which is convenient for operators to pour various materials weighed according to the neodymium iron boron magnet formula into the screening groove 206. A coarse filter plate 208 and a fine filter plate 209 are arranged up and down in the screening groove 206 to perform particle size screening on the materials. The coarse filter plate 208 has larger sieve holes and is responsible for intercepting large pieces of materials with excessive particle sizes. The fine filter plate 209 has smaller sieve holes and intercepts relatively large particle materials, ensuring that only materials with qualified particle sizes can pass through. A return port 210 and a grinding port 211 are provided on one side of the screening box 201 corresponding to the coarse filter plate 208 and the fine filter plate 209 to plan different outlets for materials with different particle sizes. One end of the return pipe 204 is connected to the return port 210, and the other end is connected to an external pulverizer. The material blocks that do not meet the particle size requirements intercepted by the coarse filter plate 208 are transported to the external pulverizer through the return port 210 and the return pipe 204 for further pulverization treatment according to the material recycling process. One side of the grinding port 211 is connected to the airflow pulverization assembly through a feed check valve pipe 202. The relatively large particle materials intercepted by the fine filter plate 209 enter the airflow pulverization chamber 301 through the grinding port 211 and the feed check valve pipe 202 for further pulverization processing. The discharge port formed at the bottom end of the screening box 201 serves as the qualified material outlet, and a first feed pipe 203 is provided at the bottom of the discharge port. A second feed pipe 104 is also provided at the top of the top cover 102. The bottom end of the first feed pipe 203 is connected to the second feed pipe 104, and the qualified material particles fall into the mixing tank body 101 through this channel for mixing.

[0056] Please refer to Figure 12As shown in the figure, to ensure the stable installation of the coarse filter plate 208 and the fine filter plate 209 in the screening box 201, two sets of mounting blocks 213 are provided on the inner walls on both sides of the screening groove 206. The two ends of the coarse filter plate 208 and the fine filter plate 209 are respectively connected to the four sets of mounting blocks 213, ensuring that there is no risk of shaking and displacement of the filter plates during long-term screening operations, and guaranteeing the stability of the screening effect; on one side of the screening box 201, two sets of first collecting covers 214 are provided corresponding to the return material port 210 and the grinding port 211. The two sets of first collecting covers 214 are respectively connected to the feed one-way pipe 202 and the return material pipe 204, collecting the intercepted materials and guiding them to smoothly enter the corresponding pipes. The materials intercepted by the coarse filter plate 208 enter the return material pipe 204 through the corresponding first collecting cover 214, and the larger particle materials intercepted by the fine filter plate 209 enter the feed one-way pipe 202 through the corresponding first collecting cover 214; at the bottom of the screening box 201, a second collecting cover 215 is installed corresponding to the discharge port. A through groove is opened at the top of the third mounting seat 205 corresponding to the second collecting cover 215 to provide an installation space for the second collecting cover 215. The second collecting cover 215 passes through the through groove and is connected to the top end of the first feed pipe 203. The qualified material particles falling from the discharge port are transported to the mixing tank body 101 through the first feed pipe 203.

[0057] Please refer to as Figure 13 And Figure 14 As shown in the figure, a partition plate 216 is provided in the screening groove 206. The coarse filter plate 208 and the fine filter plate 209 are both located on one side of the partition plate 216. An installation plate 217 is provided on the third mounting seat 205. An eccentric motor 218 is provided on the top of the installation plate 217. Sliding through grooves 219 are opened at the bottom of the third mounting seat 205 and the screening box 201. Two slidable movable rods 220 are provided in the two sliding through grooves 219. The bottom ends of the two movable rods 220 are both connected to a T-shaped plate 221. The main shaft of the eccentric motor 218 is rotatably connected to the T-shaped plate 221. Limit seats 222 are provided at the bottoms of the two sliding through grooves 219. Limit grooves 223 are opened on the two movable rods 220. The two limit seats 222 are slidably connected to the two limit grooves 223. The top ends of the two movable rods 220 are respectively connected to the coarse filter plate 208 and the fine filter plate 209. On the other side of the partition plate 216, two sets of third collecting covers 224 are provided corresponding to the return material port 210 and the grinding port 211. A first through hole is opened on one side of each of the two sets of third collecting covers 224. A fourth collecting cover 225 is provided at the bottom of the fine filter plate 209. A second through hole is opened at the bottom of the fourth collecting cover 225 corresponding to the discharge port. A through groove is opened on the partition plate 216 corresponding to the fine filter plate 209.

[0058] A mixing method for a mixing device used in the production of neodymium iron boron magnets includes the following steps:

[0059] Step 1: Material feeding;

[0060] Weigh various materials required according to the formula of NdFeB magnets, and pour the materials into the screening tank 206 of the screening box 201 through the feed hopper 207. During the feeding process, pay attention to the flow rate of the materials at all times to avoid the accumulation and blockage of materials in the screening tank 206 due to too fast pouring, which will affect the normal progress of the subsequent screening process;

[0061] Step Two: Material Screening;

[0062] After the materials enter the screening tank 206 of the screening box 201, they pass through the coarse filter plate 208 and the fine filter plate 209 distributed up and down in sequence. The sieve hole size of the coarse filter plate 208 is relatively large, which is used to intercept large pieces of materials that obviously do not meet the particle size requirements. The large pieces of materials are discharged through the return pipe 204 along the return port 210. The other end of the return pipe 204 is connected to an external crusher. These intercepted large pieces of materials will be transported to the external crusher and undergo crushing treatment again to refine their particle size; the materials passing through the coarse filter plate 208 continue to flow downward and encounter the fine filter plate 209. The sieve holes of the fine filter plate 209 are small, which can intercept materials with relatively large particles. These relatively large particle materials intercepted by the fine filter plate 209 enter the air flow crushing chamber 301 through the grinding port 211 and the feeding one-way pipe 202 connected thereto; at the same time, those qualified material particles screened by the coarse filter plate 208 and the fine filter plate 209 fall into the mixing tank body 101 through the channel composed of the first feeding pipe 203 and the second feeding pipe 104 at the bottom discharge port of the screening box 201;

[0063] Step Three: Air Flow Crushing;

[0064] When there is material that needs to be processed by air jet milling, start the drive motor 306 to drive the fan 302 to work. External gas is inhaled into the fan 302 through the air inlet pipe 309. After the inhaled gas is pressurized in the fan 302, it is transported to the dust filter 303 through the gas transmission pipe 307 connected to the top. The dust filter 303 intercepts fine impurities such as dust in the gas, ensuring that the purity of the gas entering the air jet milling chamber 301 meets the standard and preventing impurities from mixing into the material and affecting the quality of the magnet. The gas purified by dust filtration enters the air jet milling chamber 301 through the pulverizing gas inlet pipe 308. In the air jet milling chamber 301, the gas enters the jet ring 314 between the airway top plate 312 and the airway bottom plate 313, and then jets out at high speed from multiple groups of pulverizing jet orifices 315 on the peripheral side, creating a high-intensity impact environment in the pulverizing groove 311. At this time, the larger particle material entering the air jet milling chamber 301 from the feed check valve 202 collides and rubs against each other under the impact of the high-speed air flow and is pulverized into finer particles to meet the requirements for the particle size of the material. The pulverized material is discharged from the second discharge pipe 316 at the bottom of the air jet milling chamber 301. The second check valve 317 at the bottom end of the second discharge pipe 316 ensures that the material can only flow downward, allowing it to fall into the mixing tank body 101 through the feed port 103 at the top of the top cover 102 and converge with the previously entered qualified material to prepare for stirring;

[0065] Step Four: Mixing and Stirring;

[0066] After all the materials enter the mixing tank body 101, start the concentric double-shaft motor 406. The two main shafts of the concentric double-shaft motor 406 serve as power output ends, respectively driving the connected first connecting shaft 408 and second connecting shaft 409 to rotate. When the first connecting shaft 408 rotates, it drives the two groups of spiral turning blades 402 to rotate in the turning cavity 404 through the connecting pieces 412 and connecting frames 413 on both sides, driving the two groups of spiral turning blades 402 to rotate in the turning cavity 404. During the rotation process, the materials in the turning cavity 404 are continuously turned upward, enabling them to enter the top mixing cavity 405, realizing the preliminary transfer of materials between different chambers. At the same time, the two groups of scraping plates 414 also rotate along with the connecting frame 413. One side of the scraping plate 414 fits against the inner wall of the mixing tank body 101, capable of scraping off the materials on the inner wall of the top mixing cavity 405. The guiding cover 415 provided at the bottom end of the connecting frame 413 corresponding to the spiral turning blade 402 can guide the materials that are turned up from the turning cavity 404 and gather in the top mixing cavity 405 to flow towards the inner mixing cavity 403 according to the material flow direction, ensuring the smoothness and orderliness of the circulating flow of materials between chambers. When the second connecting shaft 409 rotates, it drives the three groups of first stirring frames 417 in the top mixing cavity 405 and the two groups of second stirring frames 422 in the inner mixing cavity 403 to rotate synchronously. The three groups of first stirring plates 419 on the first stirring frame 417 stir the materials in the top mixing cavity 405. Since the three groups of first stirring plates 419 all face the second connecting shaft 409, during the stirring process, the materials gather towards the second connecting shaft 409 and naturally fall into the inner mixing cavity 403 under the action of gravity, realizing the transfer of materials between chambers. Similarly, the three groups of second stirring plates 423 on the second stirring frame 422 stir the materials in the inner mixing cavity 403. The three groups of second stirring plates 423 all face the bottom of the inner mixing cavity 403, pushing the materials towards the bottom. In addition, the pushing plate 425 provided at the bottom end of the second connecting shaft 409 corresponding to the multiple groups of communication grooves 424 pushes the materials at the bottom of the inner mixing cavity 403 near the communication grooves 424 as the second connecting shaft 409 rotates, facilitating the materials to smoothly pass through the communication grooves 424 and enter the turning cavity 404, realizing the continuous circulating flow of materials between different chambers. Repeating this process ensures that various materials are fully and evenly mixed in the mixing tank body 101;

[0067] Step Five: Processing of the mixed materials;

[0068] After the materials are evenly mixed, open the first one-way valve 105 at the bottom of the mixing tank body 101, and discharge the mixed materials through the first discharge pipe 106.

[0069] Example 2: Based on the mixing device and mixing method for producing neodymium iron boron magnets provided in Example 1 of the present application, Example 2 of the present application proposes a mixing device and mixing method for producing neodymium iron boron magnets. Example 2 is only a preferred mode of Example 1, and the implementation of Example 2 will not affect the independent implementation of Example 1. The following will further illustrate the second embodiment of the present invention.

[0070] Please refer to Figure 13 As shown in Figure 14 In the screening tank 206, a partition plate 216 is provided to separate the space in the screening tank 206. The coarse filter plate 208 and the fine filter plate 209 are both located on the same side of the partition plate 216. An installation plate 217 is provided on the third mounting seat 205, and an eccentric motor 218 is provided at the top of the installation plate 217. At corresponding positions on the bottom of the third mounting seat 205 and the screening box 201, two groups of sliding through grooves 219 are opened. In both of these two groups of sliding through grooves 219, slidable movable rods 220 are provided. The bottoms of the two groups of movable rods 220 are both connected to a T-shaped plate 221, and the main shaft of the eccentric motor 218 is rotatably connected to the T-shaped plate 221. To ensure the stability of the movable rod 220 during the reciprocating sliding process, limit seats 222 are provided at the bottoms of the two groups of sliding through grooves 219. Correspondingly, limit grooves 223 are opened on the two groups of movable rods 220, and the limit seats 222 and the limit grooves 223 are slidably connected. The tops of the two groups of movable rods 220 are respectively connected to the coarse filter plate 208 and the fine filter plate 209. When the eccentric motor 218 is started, the rotational motion of the main shaft is converted into the reciprocating linear motion of the T-shaped plate 221, and then the vibration force is transmitted to the upper coarse filter plate 208 and fine filter plate 209 through the movable rod 220; on the other side of the partition plate 216, corresponding to the material return port 210 and the grinding port 211, two groups of third aggregate covers 224 are provided to collect the materials that have not passed through the coarse filter plate 208 or the fine filter plate 209. A through groove is provided on the partition plate 216 corresponding to the fine filter plate 209, so that the larger particle size materials that have not passed through the fine filter plate 209 fall into one of the third aggregate covers 224 through the through groove; on one side of each of the two groups of third aggregate covers 224, a first through hole is opened, which is respectively communicated with the material return pipe 204 and the feed one-way pipe 202. A fourth aggregate cover 225 is provided at the bottom of the fine filter plate 209, which is responsible for collecting the qualified materials screened by the fine filter plate 209. A second through hole is opened at the bottom of the fourth aggregate cover 225 and communicated with the discharge port.

[0071] Compared with the filtering method in Embodiment 1 that only relies on the static coarse filter plate 208 and fine filter plate 209 for filtering, in this Embodiment 2, an eccentric motor 218 is installed on the mounting plate 217, and its main shaft is connected to the T-shaped plate 221. Then, through two groups of movable rods 220, they are respectively connected to the coarse filter plate 208 and the fine filter plate 209. The main difference is that by starting the eccentric motor 218, the coarse filter plate 208 and the fine filter plate 209 can vibrate along the two groups of sliding through grooves 219. This vibration mode, compared with the static filtering method, can effectively break the possible agglomeration force between material particles, prompt the material to disperse quickly and evenly on the surface of the filter plate, improve the filtering efficiency, and reduce the filtering time. Therefore, compared with the filtering method using the static coarse filter plate 208 and fine filter plate 209, such a vibration screening method can use the vibration force to disperse the material, prevent it from blocking in the filter holes and affecting the filtering effect, and ensure the continuity and stability of the screening process; the remaining conditions are the same as those in Embodiment 1, so this embodiment will not be elaborated here.

[0072] The above-described embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A mixing device for producing neodymium iron boron magnets, comprising a mixing tank body (101), characterized in that: A detachable top cover (102) is provided at the top of the mixing tank body (101). A screening component and an air flow crushing component are provided at the top of the top cover (102). The screening component includes a screening box (201). The screening box (201) is provided at the top of the top cover (102). The air flow crushing component includes an air flow crushing chamber (301). One side of the screening box (201) is connected to the air flow crushing chamber (301). A stirring chamber is provided inside the mixing tank body (101). A stirring component is provided in the stirring chamber. The stirring component includes a partition cover (401) and two groups of spiral turning blades (402). The partition cover (401) divides the stirring chamber into an inner mixing chamber (403), a turning chamber (404) and a top mixing chamber (405). A plurality of communication grooves (424) for communicating the inner mixing chamber (403) and the turning chamber (404) are provided at the bottom end of the partition cover (401). Both groups of spiral turning blades (402) are located in the turning chamber (404). The bottom of the mixing tank body (101) is connected to a first discharge pipe (106) through a first one-way valve (105); Both the top of the inner mixing chamber (403) and the top of the turning chamber (404) are communicated with the top mixing chamber (405). The stirring component further includes a concentric double-shaft motor (406). A first mounting seat (407) is provided at the top of the top cover (102). The concentric double-shaft motor (406) is provided at the top of the first mounting seat (407). A first connecting shaft (408) and a second connecting shaft (409) are provided in the stirring chamber. A through hole is provided at the top of the first connecting shaft (408). The second connecting shaft (409) is inserted into the through hole. Mounting holes (410) are provided on both the top cover (102) and the first mounting seat (407). Two main shafts of the concentric double-shaft motor (406) pass through the two mounting holes (410) and are respectively connected to the first connecting shaft (408) and the second connecting shaft (409). A sealing sleeve (411) is provided in the mounting hole (410) on the top cover (102); Connectors (412) are provided on both sides of the first connecting shaft (408). Connecting frames (413) are provided at the corresponding ends of the two groups of connectors (412). The bottom ends of the two groups of connecting frames (413) are respectively connected to the two groups of spiral turning blades (402). Both groups of spiral turning blades (402) are in contact with the inner wall of the mixing tank body (101) and the outer side of the partition cover (401); Two scraping plates (414) are respectively provided on the corresponding sides of the two groups of connecting frames (413). Both groups of scraping plates (414) are located in the top mixing chamber (405). One side of both groups of scraping plates (414) is in contact with the inner wall of the mixing tank body (101). Guide covers (415) facing the inner mixing chamber (403) are respectively provided at the bottom ends of the two groups of connecting frames (413) corresponding to the spiral turning blades (402); There are two groups of first connection seats (416) corresponding to the top mixing chamber (405) on the second connection shaft (409). There are three groups of first stirring frames (417) arranged in the top mixing chamber (405). One side of the three groups of first stirring frames (417) is connected to the two groups of first connection seats (416) respectively through two groups of first connecting rods (418). There are three groups of first stirring plates (419) facing the second connection shaft (409) arranged in the first stirring frame (417). There are also two groups of second connection seats (420) corresponding to the inner mixing chamber (403) on the second connection shaft (409). Both sides of the two groups of second connection seats (420) are connected with second stirring frames (422) through two groups of second connecting rods (421). There are three groups of second stirring plates (423) facing the bottom of the inner mixing chamber (403) arranged on the second stirring frame (422). A pushing plate (425) is arranged at the bottom end of the second connection shaft (409) corresponding to multiple groups of the communication grooves (424). One side of the two groups of second stirring frames (422) is in contact with the inner wall of the partition cover (401); The screening assembly further includes a first feed pipe (203) and a return pipe (204). A third mounting seat (205) is arranged on the top of the top cover (102). The screening box (201) is arranged on the top of the third mounting seat (205). A screening groove (206) is opened at the top of the screening box (201). A feed hopper (207) is arranged at the top of the screening groove (206). A coarse filter plate (208) and a fine filter plate (209) are arranged up and down in the screening groove (206). A return opening (210) and a grinding opening (211) are opened on one side of the screening box (201) corresponding to the coarse filter plate (208) and the fine filter plate (209). One end of the return pipe (204) is connected to the return opening (210), and the other end of the return pipe (204) is connected to an external pulverizer. One side of the grinding opening (211) is connected to the air flow pulverizing assembly through a feed one-way pipe (202). An outlet is opened at the bottom end of the screening box (201), and the first feed pipe (203) is arranged at the bottom of the outlet. A second feed pipe (104) is also arranged on the top of the top cover (102), and the bottom end of the first feed pipe (203) is connected to the second feed pipe (104); A partition plate (216) is arranged in the screening tank (206). Both the coarse filter plate (208) and the fine filter plate (209) are located on one side of the partition plate (216). An installation plate (217) is arranged on the third mounting seat (205). An eccentric motor (218) is arranged on the top of the installation plate (217). Sliding through grooves (219) are formed in both the third mounting seat (205) and the bottom of the screening box (201). Slidable movable rods (220) are arranged in the two sliding through grooves (219). The bottoms of the two movable rods (220) are connected to a T-shaped plate (221). The main shaft of the eccentric motor (218) is rotatably connected to the T-shaped plate (221). Limit seats (222) are arranged at the bottoms of the two sliding through grooves (219). Limit grooves (223) are formed in the two movable rods (220). The two limit seats (222) are slidably connected to the two limit grooves (223). The tops of the two movable rods (220) are respectively connected to the coarse filter plate (208) and the fine filter plate (209). On the other side of the partition plate (216), two third aggregate covers (224) are arranged corresponding to the material return port (210) and the grinding port (211). First through holes are formed in one sides of the two third aggregate covers (224). A fourth aggregate cover (225) is arranged at the bottom of the fine filter plate (209). A second through hole is formed in the bottom of the fourth aggregate cover (225) corresponding to the discharge port. A through groove is formed in the partition plate (216) on one side corresponding to the fine filter plate (209).

2. The mixing device for producing neodymium iron boron magnets according to claim 1, wherein: The air flow crushing assembly further includes a blower (302) and a dust filter (303). A second mounting seat (304) is arranged on the top of the top cover (102). The dust filter (303) is connected to the top of the second mounting seat (304) by screws. An installation bracket (305) is arranged on one side of the mixing tank body (101). The blower (302) is installed on the installation bracket (305). A driving motor (306) is arranged at the bottom of the blower (302). One end of an air delivery pipe (307) is connected to the top. The other end of the air delivery pipe (307) is connected to the dust filter (303). One side of the dust filter (303) is connected to the air flow crushing chamber (301) through a crushing gas inlet pipe (308). An air inlet pipe (309) connected to an external air path is arranged at the air inlet on one side of the blower (302). A pressure regulating valve (310) is arranged on the air delivery pipe (307).

3. The mixing device for producing neodymium iron boron magnets according to claim 2, characterized in that: A crushing groove (311) is arranged in the air flow crushing bin (301). The screening assembly is communicated with the crushing groove (311) through a feed one-way pipe (202). An air passage top plate (312) and an air passage bottom plate (313) are arranged in the crushing groove (311). The air passage top plate (312) and the air passage bottom plate (313) are connected by a jet ring (314). A through hole communicated with the crushing gas inlet pipe (308) is formed at the top of the air passage top plate (312). A plurality of groups of crushing jet orifices (315) are formed on the circumferential side of the jet ring (314). A second discharge pipe (316) is arranged at the bottom of the air flow crushing bin (301). A second one-way valve (317) is arranged at the bottom end of the second discharge pipe (316). A feed inlet (103) is formed at the top of the top cover (102). The bottom end of the second one-way valve (317) is connected with the feed inlet (103).

4. A mixing device for producing neodymium iron boron magnets according to claim 1, characterized in that: Two groups of mounting blocks (213) are arranged on the inner walls on both sides of the screening groove (206). The two ends of the coarse filter plate (208) and the fine filter plate (209) are respectively connected with the four groups of mounting blocks (213). Two groups of first aggregate covers (214) are arranged on one side of the screening box (201) corresponding to the return material port (210) and the grinding port (211). The two groups of first aggregate covers (214) are respectively connected with the feed one-way pipe (202) and the return material pipe (204). A second aggregate cover (215) is arranged at the bottom of the screening box (201) corresponding to the discharge port. A through groove is formed at the top of the third mounting seat (205) corresponding to the second aggregate cover (215). The second aggregate cover (215) passes through the through groove and is connected with the top end of the first feed pipe (203).

5. The mixing method of a mixing device for producing neodymium iron boron magnets according to any one of claims 1-4, characterized in that: It includes the following steps: Step 1: Material feeding; Weigh various required materials according to the formula of the neodymium iron boron magnet, and pour the materials into the screening groove (206) of the screening box (201) through the feed hopper (207). Step 2: Material screening; The materials pass through the coarse filter plate (208) and the fine filter plate (209) which are distributed up and down in sequence. The material blocks that do not meet the particle size requirements will be intercepted by the coarse filter plate (208), discharged through the return material port (210) and the return material pipe (204), and transported to an external crusher for re-crushing treatment for subsequent reuse. The larger particle materials are intercepted by the fine filter plate (209), enter the air flow crushing bin (301) through the grinding port (211) and the feed one-way pipe (202), and the qualified material particles fall into the mixing tank body (101) from the discharge port at the bottom end of the screening box (201) through the first feed pipe (203) and the second feed pipe (104). Step 3: Air flow crushing; Start the drive motor (306) to drive the fan (302) to work. External gas is inhaled into the fan (302) through the air inlet pipe (309). After the inhaled gas is pressurized in the fan (302), it is transported to the dust filter (303) through the air delivery pipe (307). The dust filter (303) filters out fine impurities such as dust in the gas. The purified gas enters the airflow pulverization chamber (301) through the pulverized gas inlet pipe (308). In the airflow pulverization chamber (301), the gas enters the jet ring (314) between the airway top plate (312) and the airway bottom plate (313), and then jets out at high speed from multiple groups of pulverization jet orifices (315) on the peripheral side. At this time, the larger particle materials entering the airflow pulverization chamber (301) from the feed one-way pipe (202) collide and rub against each other under the impact of the high-speed airflow and are pulverized into finer particles to meet the requirements for the particle size of the materials. The pulverized materials are discharged from the second discharge pipe (316) at the bottom of the airflow pulverization chamber (301). The second one-way valve (317) at the bottom end of the second discharge pipe (316) ensures that the materials can only flow downward and fall into the mixing tank body (101) through the feed inlet (103) to prepare for mixing and stirring; Step Four: Mixing and Stirring; After all the materials enter the mixing tank body (101), start the concentric double-shaft motor (406). The two main shafts of the concentric double-shaft motor (406) drive the first connecting shaft (408) and the second connecting shaft (409) to rotate respectively. When the first connecting shaft (408) rotates, it drives two groups of spiral turning blades (402) to rotate in the turning cavity (404) through the connecting pieces (412) and the connecting frames (413) on both sides, continuously turning the materials in the turning cavity (404) upward to make them enter the top mixing cavity (405). At the same time, two groups of scraping plates (414) on the connecting frame (413) rotate in the top mixing cavity (405). One side of the scraping plate (414) contacts the inner wall of the mixing tank body (101), scraping the materials on the inner wall of the top mixing cavity (405) to make them participate in the mixing again. The guiding cover (415) can guide the materials in the top mixing cavity (405) to flow into the inner mixing cavity (403). When the second connecting shaft (409) rotates, it drives three groups of first stirring frames (417) in the top mixing cavity (405) and two groups of second stirring frames (422) in the inner mixing cavity (403) to rotate synchronously. Three groups of first stirring plates (419) in the first stirring frame (417) stir and mix the materials in the top mixing cavity (405). At the same time, the three groups of first stirring plates (419) all face the second connecting shaft (409), making the materials in the top mixing cavity (405) approach the second connecting shaft (409) and fall into the inner mixing cavity (403) under the action of gravity; three groups of second stirring plates (423) stir the materials in the inner mixing cavity (403). At the same time, the three groups of second stirring plates (423) all face the bottom of the inner mixing cavity (403), making the materials move towards the bottom of the inner mixing cavity (403). The bottom end of the second connecting shaft (409) is connected to a pushing disc (425). The pushing disc (425) rotates to push the materials at the bottom of the inner mixing cavity (403) into the connecting groove (424), and makes them enter the turning cavity (404) through the connecting groove (424), realizing the circulating flow of materials between different chambers and ensuring the full and uniform mixing of various materials in the mixing tank body (101); Step Five: Processing of the mixed materials; After the materials are mixed evenly, open the first one-way valve (105) at the bottom of the mixing tank body (101), and discharge the mixed materials through the first discharge pipe (106).

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