NdFeB magnetic powder preparation device

Abstract

The invention discloses a neodymium iron boron magnetic powder preparation device, and belongs to the field of neodymium iron boron magnetic powder preparation. The device comprises a vacuum arc remelting rapid quenching furnace, wherein the vacuum arc remelting rapid quenching furnace comprises an arc remelting device, an overflow liquid guide mechanism, a rapid quenching powder making device and an auxiliary system; the overflow liquid guide mechanism comprises a liquid guide assembly, and the liquid guide assembly comprises a conical flow guide opening, a ceramic filter element, an electromagnetic flow valve and a flow guide groove; the rapid quenching powder making device comprises a cooling rotating wheel, a driving assembly and a magnetic powder collecting assembly. Meanwhile, floating and settling impurities in the melt are filtered through the arrangement of the filtering assembly, the melt entering the rapid quenching device is prevented from containing the impurities, the uniformly flowing melt is cooled through the arrangement of the cooling rotating wheel in the rapid quenching device, the melt is uniformly cooled and pulverized through the rapid quenching device, a fine grain structure is formed, and the quality of the melt is improved. The thermal expansion rate of the magnetic powder is reduced; and the characteristics of low expansion and high magnetic performance of the magnetic powder are ensured.

Description

Technical Field

[0001] This invention relates to the field of neodymium iron boron magnetic powder preparation, and particularly to a neodymium iron boron magnetic powder preparation apparatus. Background Technology

[0002] Bonded NdFeB magnets are made by combining NdFeB magnetic powder and a binder. The manufacturing process of bonded NdFeB magnets includes: mixing the NdFeB magnetic powder and binder, molding, curing, post-treatment, coating, and magnetization. Currently, all bonded NdFeB magnets are manufactured in a single molding process. After a single use, the dimensions of the molded magnet need to be redesigned to obtain a bonded NdFeB magnet that meets the dimensional requirements.

[0003] The manufacturing methods for the aforementioned neodymium iron boron magnets generally suffer from the following drawbacks: The method of remaking the compression molding die requires remaking the die based on the magnet's thermal expansion rate. This results in a dedicated die for each magnet, leading to high manufacturing costs and long production cycles. Uneven cooling rates in existing rapid quenching equipment cause significant differences in magnetic powder grain size, and clogging of the filter components introduces impurities into the molten metal, exacerbating fluctuations in the magnetic powder's thermal expansion rate. This necessitates repeated calculations of the expansion rate and die remaking. Furthermore, as the types of magnets increase, the types and number of dies also increase, consuming substantial resources and increasing die management costs. Adjusting the NdFeB magnetic powder composition involves using the existing compression molding die while modifying the composition of the raw material, NdFeB magnetic powder. However, the adjusted NdFeB magnetic powder also requires experimental verification of its thermal expansion rate. Therefore, both methods require calculation of the magnetic expansion rate. Summary of the Invention

[0004] This invention provides a neodymium iron boron magnetic powder preparation device, which can solve the problem of calculating the magnet expansion rate when preparing neodymium iron boron magnet models.

[0005] One of the objectives of this invention is achieved through the following technical solution: In a first aspect, this application provides a neodymium iron boron magnetic powder preparation apparatus, including a vacuum arc remelting rapid quenching furnace, wherein the vacuum arc remelting rapid quenching furnace is provided with an arc remelting device, an overflow guiding mechanism, a rapid quenching powder preparation device, and an auxiliary system; The overflow guiding mechanism includes a guiding component, which includes a conical guide port, a ceramic filter element, an electromagnetic flow valve, and a guiding groove. The conical guide port is connected to the crucible assembly, and the guiding groove is inclined. The inlet of the guiding groove is connected to the outlet of the ceramic filter element, and the outlet is directly opposite the rapid quenching powder preparation device. The rapid quenching powder making device includes a cooling wheel, a drive assembly, and a magnetic powder collecting assembly. The outlet of the guide channel is directly opposite the cooling wheel. The magnetic powder collecting assembly includes a sealed collecting chamber located directly below the cooling wheel.

[0006] A further aspect of the present invention is that the arc remelting device includes a crucible assembly and an arc generating assembly. The crucible assembly is designed to be inclined so that the molten liquid is collected by an overflow guiding mechanism. The arc generating assembly includes an upper electrode and a lower electrode, which are respectively located at the top and bottom of the crucible assembly.

[0007] A further aspect of the present invention is that the crucible assembly includes a water-cooled copper crucible, and a water-cooling pipe is wound around the outside of the water-cooled copper crucible.

[0008] A further aspect of the present invention is that the arc generating assembly further includes a lifter, which adjusts the distance between the upper electrode and the surface of the raw material liquid.

[0009] A further aspect of the present invention is that a heating belt is wound around the outer periphery of the flow guide groove, and the flow guide groove forms an angle with the horizontal direction.

[0010] A further aspect of the present invention is that the drive assembly includes a variable frequency motor, and a torque sensor is provided between the variable frequency motor and the cooling roller of the cooling wheel.

[0011] A further aspect of the present invention is that the auxiliary system includes an inertia protection system, a temperature control system, and a control system.

[0012] A further aspect of the present invention is that: a filter assembly is provided between the two ends of the conical guide port and the water-cooled copper crucible and the ceramic filter element; a rectangular liquid outlet is provided on the water-cooled copper crucible; the two ends of the conical guide port are rotatably connected to the rectangular liquid outlet and the ceramic filter element, respectively; a servo motor is provided on the vacuum arc remelting rapid quenching furnace; and a gear set is provided between the outer periphery of the conical guide port and the servo motor, so that the servo motor drives the conical guide port to rotate.

[0013] A further aspect of the present invention is that: the filter assembly includes a ceramic filter screen, the ceramic filter screen is fixedly installed on a conical guide port and located between the conical guide port and a rectangular liquid outlet, a front scraper is fixedly installed inside the rectangular liquid outlet, the front scraper is in contact with the ceramic filter screen, and a rear scraper is fixedly installed at the liquid outlet end of the conical guide port, the rear scraper is in contact with the liquid inlet of the ceramic filter element.

[0014] A further aspect of the present invention is that a recovery assembly is provided between the rectangular outlet and the water-cooled copper crucible. The recovery assembly includes an upper reflux channel and a lower reflux channel. The upper reflux channel is located at the top of the rectangular outlet, and the outlet is located at the connection between the rectangular outlet and the conical guide port. The inlet is located inside the water-cooled copper crucible, and the outlet is positioned higher than the inlet, so that the slag floating in the molten liquid can be recovered into the water-cooled copper crucible through the upper reflux channel. The lower reflux channel is located at the bottom of the rectangular outlet, so that the slag settling in the molten liquid can be recovered into the water-cooled copper crucible through the lower reflux channel.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: By tilting the water-cooled copper crucible to ensure uniform molten metal collection, and by using a filtration system to filter floating and settling impurities from the molten metal, and by using a recovery system to recover the filtered impurities, the clogging of the ceramic filter element and the accumulation of excessive impurities near the conical guide port are prevented. This avoids impurities in the molten metal entering the rapid quenching unit, which would cause significant fluctuations in the thermal expansion rate of the magnetic powder, necessitating repeated calculations of the expansion rate and re-molding. Combined with precise flow control using an electromagnetic flow valve, the molten metal is uniformly transported to the rapid quenching unit via the guide channel. The cooling wheel in the rapid quenching unit cools the uniformly flowing molten metal, ensuring uniform cooling and powder formation to achieve a fine-grained structure. Simultaneously, the addition of zirconium to form Nd-Zr-O compounds at the NdFeB grain boundaries inhibits abnormal grain growth, reduces thermal expansion stress at the grain boundaries, optimizes magnetic powder performance, and lowers the thermal expansion rate of the magnetic powder, ensuring that the magnetic powder possesses low expansion and high magnetic properties. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the liquid guiding component structure of the present invention; Figure 3 This is a schematic diagram of the connection structure of the water-cooled copper crucible, the conical flow guide, and the ceramic filter element of the present invention. Figure 4 This is a schematic diagram of the structure of the filtration component and the recycling component of the present invention; Figure 5 For the present invention Figure 4 Schematic diagram of the structure of section A; Figure 6 For the present invention Figure 4 Schematic diagram of section B in the middle; Figure 7 This is a front structural cross-sectional view of the water-cooled copper crucible and conical flow guide of the present invention.

[0017] In the diagram: 100, Vacuum arc remelting rapid quenching furnace; 101, Servo motor; 102, Gear set; 200, Arc remelting device; 210, Crucible assembly; 211, Water-cooled copper crucible; 2111, Rectangular liquid outlet; 212, Water cooling pipe; 220, Arc generating assembly; 221, Upper electrode; 222, Lower electrode; 223, Lifting device; 300, Overflow guiding mechanism; 310, Liquid guiding assembly; 311, Conical guide port; 312, Ceramic filter element; 313, Electromagnetic flow valve; 314, Guide groove; 3 15. Heating belt; 400. Rapid quenching powder preparation device; 410. Cooling wheel; 420. Drive assembly; 421. Variable frequency motor; 422. Torque sensor; 430. Magnetic powder collection assembly; 431. Sealed collection chamber; 500. Auxiliary system; 510. Inertia protection system; 520. Temperature control system; 530. Control system; 600. Filter assembly; 601. Ceramic filter screen; 602. Front scraper; 603. Rear scraper; 700. Recovery assembly; 701. Upper return channel; 702. Lower return channel. Detailed Implementation

[0018] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0019] Example 1

[0020] like Figures 1 to 2 As shown, the present invention provides a neodymium iron boron magnetic powder preparation device, including a vacuum arc remelting rapid quenching furnace 100, which includes an arc remelting device 200, an overflow guiding mechanism 300, a rapid quenching powder preparation device 400, and an auxiliary system 500. The overflow guiding mechanism 300 includes a guiding component 310, which includes a conical guide port 311, a ceramic filter element 312, an electromagnetic flow valve 313, and a guiding groove 314. The conical guide port 311 is connected to the electric arc remelting device 200, and the guiding groove 314 is in an inclined state. The inlet of the guiding groove 314 is connected to the outlet of the ceramic filter element 312, and the outlet is directly opposite the rapid quenching powder device 400. The rapid quenching powder making device 400 includes a cooling wheel 410, a drive assembly 420, and a magnetic powder collection assembly 430. The outlet of the guide channel 314 is directly opposite the cooling wheel 410. The magnetic powder collection assembly 430 includes a sealed collection chamber 431, which is located directly below the cooling wheel 410.

[0021] The preparation process of the aforementioned NdFeB magnetic powder preparation device is as follows: Raw materials are fed into the arc remelting device 200, which melts the raw materials. During the melting process, while the auxiliary system 500 performs a vacuum operation inside the arc remelting device 200, an inert gas is introduced into the device. The protective gas, introduced during the arc remelting process, primarily isolates the molten metal from air, preventing harmful reactions between the molten metal and reactive components such as oxygen and nitrogen, thereby ensuring the stability of the remelting process and the quality of the final product. The protective gas forms a dense gas flow layer covering the surface of the arc and the molten pool, effectively blocking the intrusion of atmospheric oxygen, nitrogen, and water vapor. This avoids oxidation or nitriding of the molten metal, reducing welding defects such as porosity and cracks. It also helps maintain the stability of the electric arc combustion, optimizes droplet transfer and molten pool flow. In addition to introducing protective gas at the arc remelting device 200, annular protective gas nozzles are installed around the cooling rollers of the cooling rotor 410 at the outlet of the guide channel 314. The protective gas is introduced during the cold extraction process of the metal solution primarily to isolate oxygen and prevent oxidation and deterioration of metal ions or active components in the solution. The protective gas is usually a chemically stable rare gas because it is less likely to react with substances in the system. At low temperatures, although the reaction rate is lower, some metal ions or organic ligands may still come into contact with dissolved oxygen and be oxidized, leading to a decrease in extraction efficiency or product purity. By introducing protective gas, the air inside the device can be exhausted, creating an inert environment to avoid oxidation side reactions. At the same time, the auxiliary system 500 monitors the temperature of the solution inside the arc remelting device 200, the temperature of the guide channel 314, and the surface temperature of the cooling roller of the cooling wheel 410 in real time, so that the temperature in the arc remelting device 200, the overflow guide mechanism 300, and the rapid quenching powder making device 400 remains relatively stable. The melt in the arc remelting device 200 flows into the conical guide port 311 and further enters the ceramic filter element 312 to filter out oxide inclusions in the solution. The flow rate of the melt is controlled by adjusting the valve opening of the electromagnetic flow valve 313, and then flows into the cooling wheel 410 through the guide channel 314. The cooling wheel 410 dissipates heat rapidly, and the speed is controlled by the variable frequency motor 421, thereby controlling the thickness of the magnetic powder. Finally, the produced magnetic powder enters the sealed collection chamber 431 below the cooling wheel 410.

[0022] A tapered flow guide 311 is used to reduce the flow resistance of the molten liquid and avoid local stagnation that leads to zirconium enrichment.

[0023] The ceramic filter element 312, made of Al2O3 with a pore size of 5-10μm, is used to filter oxide inclusions in the molten liquid. At the same time, the surface of the filter element is polished to reduce the adsorption of zirconium on the filter element surface.

[0024] The electromagnetic flow valve 313, with a response time of ≤0.1s and an adjustment accuracy of ±1%, is adopted: the molten flow signal is collected in real time by PLC, and the built-in Coriolis mass flow meter automatically adjusts the valve opening to control the molten flow rate of 50-100g / min, so that its fluctuation is ≤±3%, ensuring uniform molten thickness during rapid quenching.

[0025] The flow channel 314 is made of graphite material. The inner wall of the graphite flow channel 314 is polished, which can effectively reduce the adhesion of molten liquid.

[0026] The cooling wheel 410, made of copper, effectively ensures rapid heat dissipation of the molten liquid, cooling the uniformly flowing molten liquid, so that the rapid quenching device can uniformly cool and pulverize the molten liquid to form a fine-grained structure.

[0027] In the conventional manufacturing process of NdFeB magnets, the method for remaking the compression molding die requires remaking the die based on the magnet's expansion rate. However, the uneven cooling rate of existing rapid quenching equipment leads to large differences in magnetic powder grain size, and the 600 filter assembly is prone to clogging, resulting in impurities in the molten metal and exacerbating fluctuations in the magnetic powder's thermal expansion rate. This necessitates repeated calculations of the expansion rate and re-molding. In contrast, this application utilizes an inclined water-cooled copper crucible to ensure uniform molten metal collection. A filter assembly 600 filters floating and settling impurities from the molten metal, and a recovery assembly 700 recovers the filtered impurities. This prevents clogging of the ceramic filter element and excessive accumulation of impurities near the conical guide port, thus avoiding blockage. It also prevents impurities from entering the rapid quenching device, which would otherwise cause significant fluctuations in the thermal expansion rate of the magnetic powder, necessitating repeated calculations of the expansion rate and re-molding. Combined with precise flow control via an electromagnetic flow valve, this ensures uniform molten metal transport to the rapid quenching device via the guide channel. The cooling wheel in the rapid quenching device cools the uniformly flowing molten metal, ensuring uniform cooling and powder formation to achieve a fine-grained structure. Simultaneously, the addition of zirconium at the Nd-Zr-O grain boundaries suppresses abnormal grain growth, reduces thermal expansion stress at the grain boundaries, optimizes magnetic powder performance, and lowers the thermal expansion rate of the magnetic powder, ensuring the magnetic powder possesses low expansion and high magnetic properties.

[0028] See also Figure 1 As shown, the arc remelting device 200 includes a crucible assembly 210 and an arc generating assembly 220. The crucible assembly 210 is designed to be inclined so that the molten liquid is collected by the overflow guiding mechanism 300. The arc generating assembly 220 includes an upper electrode 221 and a lower electrode 222, which are respectively located at the top and bottom of the crucible assembly 210.

[0029] High voltage current is applied between the upper electrode 221, the lower electrode 222 and the metal to form an electric arc, generating high temperature. The electric arc energy melts the raw material and forms a molten pool. The tilted crucible assembly 210 makes it easier for the molten liquid to flow into the conical guide port 311. To avoid introducing impurities into the crucible assembly 210, both the upper electrode 221 and the lower electrode 222 are tungsten electrodes with a diameter between 8-12 mm and a purity ≥99.95%. To ensure the stability and safety of the electric arc melting process, a vacuum port is provided at the top of the crucible assembly 210 to connect to a vacuum pump, so that the ultimate vacuum degree inside the crucible assembly 210 is ≤5×10-³Pa. An inert gas inlet is provided on the side to introduce Ar gas with a purity ≥99.999% to maintain a positive pressure of 0.02-0.05MPa inside the crucible, prevent the molten liquid from oxidizing and assist in degassing. See also Figure 1 As shown, to prevent zirconium agglomeration caused by local solidification in the molten metal, the crucible assembly 210 includes a water-cooled copper crucible 211. A water-cooling pipe 212 is wrapped around the outside of the water-cooled copper crucible 211. The inner wall of the water-cooled copper crucible 211 is coated with a protective coating to prevent the molten metal from reacting with the copper wall. The material of the protective coating is preferably Al2O3. The crucible volume is 5-10L, and the bottom is designed with a 10° inclination. The inclination of the water-cooled copper crucible 211 facilitates the molten metal to converge into the conical guide port 311. The water-cooling pipe 212 is wrapped around the outside, and circulating water with a flow rate of 15-20L / min and a temperature of 30-50℃ is introduced into the water-cooling pipe 212 to control the crucible wall temperature ≤150℃ and prevent zirconium agglomeration caused by local solidification of the molten metal.

[0030] See also Figure 1 As shown, in order to ensure the stability of the electric arc, the electric arc generating component 220 also includes a lifter 223. The lifter 223 adjusts the distance between the upper electrode 221 and the raw material liquid surface. The lifter 223 is preferably set as a cylinder to control the lifting and lowering of the upper electrode 221 and adjust the distance between the electrode and the raw material liquid surface to 5-15mm to ensure the stability of the electric arc.

[0031] See also Figures 1 to 2 As shown, in order to prevent the molten liquid from cooling and solidifying in the tank, a heating belt 315 is wrapped around the outer periphery of the guide channel 314. The guide channel 314 is at an angle to the horizontal direction, and the tank body of the guide channel 314 is at a 30° angle to the horizontal direction. The inlet is connected to the outlet of the ceramic filter element 312, and the outlet is directly opposite the cooling wheel 410. The heating belt 315 is wrapped around the outer side of the guide channel 314 to keep the temperature inside the guide channel 314 between 200-300°C, thus preventing the molten liquid from cooling and solidifying inside the guide channel 314.

[0032] See also Figure 1As shown, in order to monitor the roller surface load of the cooling roller 410 in real time and avoid molten metal accumulation, the drive assembly 420 includes a variable frequency motor 421. A torque sensor 422 is installed between the variable frequency motor 421 and the cooling roller of the cooling roller 410. The cooling roller of the cooling roller 410 is connected to the variable frequency motor 421. The variable frequency motor 421 controls the rotation speed of the cooling roller on the cooling roller 410, keeping it within an adjustable range of 20-50 m / s. The rotation speed of the cooling roller 410 controls the magnetic powder thickness. When molten metal accumulates on the cooling roller 410, the variable frequency motor 421 increases the rotation speed of the cooling roller on the cooling roller 410, thereby accelerating the cooling of the molten metal. After rapid quenching, the magnetic powder falls into the sealed collection chamber 431, thereby controlling the thickness of the magnetic powder. A torque sensor 422 is installed between the motor and the cooling roller. The torque sensor 422 is used to detect the torsional torque on various rotating or non-rotating mechanical parts. The torque sensor monitors the load on the roller surface in real time and converts the physical change of the torque of the cooling roller in the cooling wheel 410 into a precise electrical signal to control the variable frequency motor 421, thereby controlling the rotation speed of the cooling wheel 410 and thus controlling the thickness of the magnetic powder. This prevents the problem of uneven cooling rate of the molten metal by the cooling wheel 410, which would lead to large differences in the grain size of the magnetic powder, aggravate the fluctuation of the thermal expansion rate of the magnetic powder, and thus require repeated calculation of the expansion rate and re-molding.

[0033] See also Figures 1 to 2 As shown, the auxiliary system 500 includes an inertia protection system 510, a temperature control system 520, and a control system 530.

[0034] This application does not limit the specific structure of the control system 530, but preferably it is a PLC control system 530 and a power supply system. The specific structure and working principle of the PLC control system 530 and the power supply system are existing technologies and will not be described in detail here. This application does not limit the specific structure of the inertia protection system 510, but preferably a vacuum pump. The specific structure and working principle of the vacuum pump are existing technologies and will not be described in detail here.

[0035] In addition to the protective gas inside the crucible assembly 210, the inert protection system 510 of this application has an Ar gas nozzle with an annular airflow velocity of 0.5-1m / s at the outlet of the guide groove 314 and around the cooling roller to form a local inert atmosphere and prevent the molten liquid from contacting the air. In this application, the temperature control system 520 monitors the temperature of the molten metal inside the crucible assembly 210 in real time via thermocouples, keeping it within the range of 1450-1550℃. Simultaneously, it monitors the temperature of the guide channel 314 and the surface temperature of the cooling rollers of the cooling wheel 410. This data is fed back to the PLC controller, which automatically adjusts the arc power, the temperature of the heating belt 315, and the flow rate of the cooling water in the water-cooling pipes 212 wrapped around the outside of the water-cooled copper crucible 211. Example 2 like Figures 3 to 7 As shown, in order to prevent the waste slag generated during the electric arc remelting reaction in the water-cooled copper crucible 211 from clogging the ceramic filter element 312, this application also provides a filter assembly 600 between the two ends of the conical guide port 311 and the water-cooled copper crucible 211 and the ceramic filter element 312. A rectangular liquid outlet 2111 is provided on the water-cooled copper crucible 2111. The two ends of the conical guide port 311 are rotatably connected to the rectangular liquid outlet 2111 and the ceramic filter element 312, respectively. A servo motor 101 is provided on the vacuum electric arc remelting rapid quenching furnace 100. A gear set 102 is provided between the outer periphery of the conical guide port 311 and the servo motor 101 so that the servo motor 101 drives the conical guide port 311 to rotate. The molten metal generated by the arc remelting reaction contains waste residue. Conventional filtration methods use a ceramic filter element 312. However, due to the small pore size of the ceramic filter element 312, while the waste residue in the molten metal is filtered out, the waste residue accumulated at the inlet of the ceramic filter element 312 can also clog it. This makes it difficult for the molten metal in the conical guide orifice 311 to flow into the guide channel 314, or even prevents the molten metal from entering the guide channel 314 at all. Therefore, this application provides a filter assembly 600, such as... Figure 4 As shown, the filter assembly 600 includes a ceramic filter screen 601, which is fixedly installed on the conical guide port 311 and located between the conical guide port 311 and the rectangular outlet port 2111. A front scraper 602 is fixedly installed inside the rectangular outlet port 2111 and is in contact with the ceramic filter screen 601. A rear scraper 603 is fixedly installed at the outlet end of the conical guide port 311 and is in contact with the inlet of the ceramic filter element 312. A ceramic filter screen 601 capable of withstanding high temperatures of 1600℃ is set between the conical guide port 311 and the rectangular outlet port 2111, which can effectively intercept waste residue in the molten liquid. A gear set 102 is set between the outer periphery of the conical guide port 311 and the servo motor 101. The servo motor 101 drives the gear set 102 to run, thereby driving the conical guide port 311. When the conical guide port 311 rotates, it drives the ceramic filter screen 601 to rotate synchronously. The ceramic filter screen 601 is attached to one side of the front scraper 602, so that the ceramic filter screen 601 is scraped by the front scraper 602 during rotation, thereby preventing the surface of the ceramic filter screen 601 from becoming blocked. At the same time, the rear scraper 603 is attached to the liquid inlet of the ceramic filter element 312, so that when the conical guide port 311 rotates, it drives the rear scraper 603 to rotate, and the rear scraper 603 scrapes the liquid inlet of the ceramic filter element 312, preventing the liquid inlet of the ceramic filter element 312 from becoming blocked. This effectively prevents the ceramic filter element 312 from becoming blocked, which would cause impurities in the melt, aggravate the fluctuation of the thermal expansion rate of the magnetic powder, and thus require repeated calculation of the expansion rate and re-molding. See also Figures 3 to 7 As shown, in order to recover the impurities accumulated at the ceramic filter screen 601, a recovery component 700 is provided between the rectangular outlet 2111 and the water-cooled copper crucible 211. The recovery component 700 includes an upper reflux channel 701 and a lower reflux channel 702. The upper reflux channel 701 is located at the top of the rectangular outlet 2111, and the outlet is located at the connection between the rectangular outlet 2111 and the conical guide port 311. The inlet is located inside the water-cooled copper crucible 211, and the outlet is positioned higher than the inlet, so that the slag floating in the molten liquid can be recovered into the water-cooled copper crucible 211 through the upper reflux channel 701. The lower reflux channel 702 is located at the bottom of the rectangular outlet 2111, so that the slag settling in the molten liquid can be recovered into the water-cooled copper crucible 211 through the lower reflux channel 702. During arc remelting, non-metallic impurities are generated, which migrate to the liquid surface due to buoyancy. At the same time, denser inclusions, such as carbides or sulfides, are generated, which sink to the bottom of the solution due to gravity. By setting an upper reflux channel 701 at the top of the rectangular outlet 2111, the inclined design of the upper reflux channel 701 allows the floating non-metallic impurities to move to the inlet of the upper reflux channel 701. Driven by the molten liquid, the floating non-metallic impurities are carried into the water-cooled copper crucible 211, thereby recovering and cleaning the impurities floating in the molten liquid. At the same time, by setting an inclined lower reflux channel 702 at the bottom of the rectangular outlet 2111, denser inclusions are driven into the water-cooled copper crucible 211 by gravity and the molten liquid, thereby recovering and cleaning the impurities that have sunk in the molten liquid. This also recovers the impurities accumulated at the ceramic filter screen 601, preventing the impurities in the molten liquid from clogging the ceramic filter screen 601.

[0036] The above-disclosed embodiments are merely a few specific examples of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A neodymium iron boron magnetic powder preparation apparatus, characterized in that, The system includes a vacuum arc remelting rapid quenching furnace, which comprises an arc remelting device, an overflow guiding mechanism, a rapid quenching powder making device, and an auxiliary system. The overflow guiding mechanism includes a guiding component, which includes a conical guide port, a ceramic filter element, an electromagnetic flow valve, and a guiding groove. The conical guide port is connected to the electric arc remelting device, and the guiding groove is inclined. The inlet of the guiding groove is connected to the outlet of the ceramic filter element, and the outlet is directly opposite the rapid quenching powder device. The rapid quenching powder making device includes a cooling wheel, a drive assembly, and a magnetic powder collecting assembly. The outlet of the guide channel is directly opposite the cooling wheel. The magnetic powder collecting assembly includes a sealed collecting chamber located directly below the cooling wheel.

2. The neodymium iron boron magnetic powder preparation apparatus according to claim 1, characterized in that, The electric arc remelting device includes a crucible assembly and an electric arc generating assembly. The crucible assembly is designed to be inclined so that the molten liquid is collected by an overflow guiding mechanism. The electric arc generating assembly includes an upper electrode and a lower electrode, which are respectively located at the top and bottom of the crucible assembly.

3. The neodymium iron boron magnetic powder preparation apparatus according to claim 1, characterized in that, The crucible assembly includes a water-cooled copper crucible, with a water-cooling pipe wound around its outer side.

4. The neodymium iron boron magnetic powder preparation apparatus according to claim 1, characterized in that, The arc generating assembly also includes a lifter, which adjusts the distance between the upper electrode and the raw material liquid surface.

5. The neodymium iron boron magnetic powder preparation apparatus according to claim 1, characterized in that, The outer periphery of the guide channel is wrapped with a heating belt, and the guide channel is at an angle to the horizontal direction.

6. The neodymium iron boron magnetic powder preparation apparatus according to claim 1, characterized in that, The drive assembly includes a variable frequency motor, and a torque sensor is provided between the variable frequency motor and the cooling roller of the cooling wheel.

7. The neodymium iron boron magnetic powder preparation apparatus according to claim 6, characterized in that, The auxiliary system includes an inertia protection system, a temperature control system, and a control system.

8. The neodymium iron boron magnetic powder preparation apparatus according to any one of claims 1-7, characterized in that, A filter assembly is provided between the two ends of the conical guide port and the water-cooled copper crucible and the ceramic filter element. A rectangular liquid outlet is provided on the water-cooled copper crucible. The two ends of the conical guide port are rotatably connected to the rectangular liquid outlet and the ceramic filter element, respectively. A servo motor is provided on the vacuum arc remelting rapid quenching furnace. A gear set is provided between the outer periphery of the conical guide port and the servo motor so that the servo motor drives the conical guide port to rotate.

9. The neodymium iron boron magnetic powder preparation apparatus according to claim 8, characterized in that, The filter assembly includes a ceramic filter screen, which is fixedly installed on a conical guide port and located between the conical guide port and a rectangular outlet. A front scraper is fixedly installed inside the rectangular outlet and is in contact with the ceramic filter screen. A rear scraper is fixedly installed at the outlet end of the conical guide port and is in contact with the inlet of the ceramic filter element.

10. The neodymium iron boron magnetic powder preparation apparatus according to claim 9, characterized in that, A recovery assembly is provided between the rectangular outlet and the water-cooled copper crucible. The recovery assembly includes an upper reflux channel and a lower reflux channel. The upper reflux channel is located at the top of the rectangular outlet, and the outlet is located at the connection between the rectangular outlet and the conical guide port. The inlet is located inside the water-cooled copper crucible, and the outlet is positioned higher than the inlet, so that the slag floating in the molten liquid can be recovered into the water-cooled copper crucible through the upper reflux channel. The lower reflux channel is located at the bottom of the rectangular outlet, so that the slag settling in the molten liquid can be recovered into the water-cooled copper crucible through the lower reflux channel.

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