A method and apparatus for microwave plasma powder production

Abstract

The application relates to a microwave plasma powder production method and device. The method comprises the following steps: starting a microwave plasma exciter of the microwave plasma powder production device; feeding working gas into a first channel of a conductor tube, and forming a microwave plasma torch in a gasification chamber and a reaction chamber below the conductor tube under excitation of the microwave plasma exciter; feeding raw material powder into the microwave plasma torch through a first powder feeding pipe, a second powder feeding pipe and a third powder feeding pipe, so that the raw material powder is sufficiently gasified under the action of the microwave plasma torch to obtain gasified powder; feeding the gasified powder into the reaction chamber by using the blowing force of the working gas, so that the gasified powder is rapidly cooled in the reaction chamber to obtain solidified spheroidized spherical powder; and sequentially collecting and filtering the spherical powder to obtain spherical powder with a target particle size. The application can improve energy utilization rate and ensure the sphericity and sphericity rate of the spherical powder.

Description

Technical Field

[0001] This application relates to the field of additive manufacturing technology, and in particular to a microwave plasma powder preparation method and apparatus. Background Technology

[0002] Spherical powders have promising market application prospects. Metal spherical powders with particle sizes of 15μm-200μm have urgent application needs in additive manufacturing, hot isostatic pressing, and injection molding. Spherical micron-sized silicon powders with particle sizes of 1μm-10μm not only have advantages such as low cost, small specific surface area, smooth surface, and good flowability, but also have higher tap density and less interfacial reaction. They are widely recognized as one of the most promising next-generation lithium battery anode materials.

[0003] Currently, the main methods for preparing micron-sized spherical powders include ball milling, high-temperature vaporization-condensation, and plasma methods. Ball milling utilizes kinetic energy to impact and grind coarse silicon material to obtain micron-sized spherical powder. While ball milling is simple, low-cost, and suitable for large-scale production, it suffers from drawbacks such as long preparation time, easy introduction of impurities, irregular powder morphology, and a wide particle size distribution. High-temperature vaporization-condensation uses electricity or laser to heat the silicon powder raw material, causing it to vaporize. The silicon vapor condenses and grows in a controlled environment. Silicon powder prepared by this method has high purity, strong particle size controllability, and good sphericity. However, it requires significant investment, high energy consumption, and demanding technical control. The plasma method uses irregular micron-sized silicon powder as raw material. The raw material powder is melted by plasma in an instant, so that the raw material powder is formed into a sphere under the action of surface tension. After rapid cooling, spherical micron-sized silicon powder is obtained. The plasma method is suitable for the production of high-end high-purity spherical silicon powder due to the advantages of high plasma temperature, rapid reaction, high product purity and good sphericity. However, the plasma method has disadvantages such as low energy utilization and unstable process.

[0004] Therefore, it is necessary to improve one or more of the problems existing in the above-mentioned related technical solutions.

[0005] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this application, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this application is to provide a microwave plasma powder preparation method and apparatus, thereby overcoming, to at least to some extent, one or more problems caused by the limitations and defects of related technologies.

[0007] According to a first aspect of the embodiments of this application, a microwave plasma powder preparation method is provided, comprising: The microwave plasma exciter of the microwave plasma powder making device is activated, and the microwaves generated by the microwave plasma exciter are conducted to the first quartz tube of the conductor tube through the plasma delivery pipe, and then coupled with the inner conductor tube inside the first quartz tube after excitation. Working gas is introduced into the first channel of the conductor tube at a first preset flow rate. Under the excitation of the microwave plasma exciter, the working gas forms a microwave plasma torch in the vaporization chamber and reaction chamber below the conductor tube. The microwave plasma torch includes a first torch region, a second torch region, and a third torch region arranged from top to bottom with torch temperatures decreasing sequentially. Raw material powder is fed into the first flare area through the first powder feeding pipe of the vaporization chamber at a first preset powder feeding angle, a first preset powder feeding rate, and a first preset powder feeding amount. Raw material powder is fed into the second flare area through the second powder feeding pipe of the vaporization chamber at a second preset powder feeding angle, a second preset powder feeding rate, and a second preset powder feeding amount. Raw material powder is fed into the third flare area through the third powder feeding pipe of the reaction chamber at a third preset powder feeding angle, a third preset powder feeding rate, and a third preset powder feeding amount. This allows the raw material powder to be fully vaporized under the action of the microwave plasma flare to obtain vaporized powder. The working gas is used to blow the gasified powder into the reaction chamber, so that the gasified powder is rapidly cooled by the cooling gas in the reaction chamber to obtain solidified spherical powder. The solidified spherical powder is collected and filtered sequentially by the separator and filter of the microwave plasma powder making device to obtain spherical powder with a median particle size of the target particle size. Wherein, the second preset powder feeding angle is greater than the third preset powder feeding angle and less than the first preset powder feeding angle, the second preset powder feeding rate is greater than the third preset powder feeding rate and less than the first preset powder feeding rate, and the second preset powder feeding amount is greater than the first preset powder feeding amount and less than the third preset powder feeding amount.

[0008] In one embodiment of this application, before the raw material powder is fed into the first flare region via the first powder feeding pipe of the gasification chamber at a first preset powder feeding angle, a first preset powder feeding rate, and a first preset powder feeding amount, the method further includes: Protective gas is introduced into the vaporization chamber through the gas inlet at a second preset flow rate. The protective gas flows downward along the inner wall of the vaporization chamber under the guidance of the second quartz tube installed in the vaporization chamber.

[0009] In one embodiment of this application, the first preset flow rate is in the range of 10m / s-15m / s, the first preset powder feeding rate is in the range of 8m / s-10m / s, the second preset powder feeding rate is in the range of 3m / s-8m / s, and the third preset powder feeding rate is in the range of 1m / s-5m / s.

[0010] In one embodiment of this application, the first preset powder feeding angle ranges from 60° to 75°, the first preset powder feeding amount ranges from 10g / min to 15g / min, the second preset powder feeding angle ranges from 30° to 60°, the second preset powder feeding amount ranges from 15g / min to 18g / min, the third preset powder feeding angle ranges from 10° to 30°, and the third preset powder feeding amount ranges from 25g / min to 30g / min.

[0011] In one embodiment of this application, the torch temperature range of the first torch region is 4500K-6000K, the torch temperature range of the second torch region is 4000K-5500K, and the torch temperature range of the third torch region is 2000K-4000K.

[0012] In one embodiment of this application, the first flare region is located in the gasification chamber, a portion of the second flare region is located in the gasification chamber and another portion is located in the reaction chamber, and the third flare region is located in the reaction chamber.

[0013] According to a second aspect of the embodiments of this application, a microwave plasma powder-making apparatus is provided, comprising: A plasma delivery pipeline, wherein a microwave plasma exciter is provided at one end of the plasma delivery pipeline and the other end is sealed; The conductor tube includes a first quartz tube and an inner conductor tube coaxially disposed inside the first quartz tube. The first quartz tube passes vertically through the plasma delivery pipe. Both ends of the first quartz tube are open. The gap between the inner wall of the first quartz tube and the outer wall of the inner conductor tube forms a first channel for the transmission of working gas. A vaporization chamber is coaxially disposed below the first quartz tube and communicates with the first quartz tube. The vaporization chamber is provided with a first powder feeding pipe and a second powder feeding pipe from top to bottom. The lower end of the inner conductor tube extends into the vaporization chamber and is located above the lower end of the first powder feeding pipe. The reaction chamber is coaxially disposed below the gasification chamber and communicates with the gasification chamber. The reaction chamber is equipped with a third powder feeding pipe. A separator and a filter are arranged sequentially in a horizontal direction, the filter, the separator and the reaction chamber are connected to the reaction chamber, and the filter is connected to the separator and the horizontal direction is perpendicular to the axial direction of the inner conductor tube. The first powder feeding pipe, the second powder feeding pipe, and the third powder feeding pipe are arranged in a staggered manner along the circumference of the gasification chamber, and the angles between the first powder feeding pipe, the second powder feeding pipe, and the third powder feeding pipe and the horizontal direction decrease sequentially.

[0014] In one embodiment of this application, the gasification chamber is provided with a through air supply hole, which is located between the first powder supply pipe and the second powder supply pipe. A second quartz tube is provided in the vaporization chamber. The gap between the outer wall of the second quartz tube and the inner wall of the vaporization chamber forms a second channel, which is connected to the air delivery hole.

[0015] In one embodiment of this application, the angle between the first powder feeding tube and the horizontal direction is in the range of 60°-75°, the angle between the second powder feeding tube and the horizontal direction is in the range of 30°-60°, and the angle between the third powder feeding tube and the horizontal direction is in the range of 10°-30°.

[0016] In one embodiment of this application, multiple first powder feeding pipes, multiple second powder feeding pipes, and multiple third powder feeding pipes are provided. The multiple first powder feeding pipes are evenly spaced along the circumference of the gasification chamber, the multiple second powder feeding pipes are evenly spaced along the circumference of the gasification chamber, and the multiple third powder feeding pipes are evenly spaced along the circumference of the gasification chamber.

[0017] The technical solutions provided by the embodiments of this application may include the following beneficial effects: In the embodiments of this application, microwaves generated by a microwave plasma exciter are conducted to a first quartz tube of a conductor tube via a plasma delivery pipe. After excitation and coupling with the inner conductor tube within the first quartz tube, the microwaves generated by the microwave plasma exciter act on the working gas in the first channel, forming a first flare region, a second flare region, and a third flare region arranged sequentially from top to bottom with progressively decreasing flare temperatures below the conductor tube. Raw material powder is fed into the first flare region, the second flare region, and the third flare region respectively through a first powder feeding pipe, a second powder feeding pipe located on the vaporization chamber, and a third powder feeding pipe located on the reaction chamber, thereby achieving multi-dimensional powder feeding and improving the energy utilization rate of the microwave plasma powder preparation device. Simultaneously... By optimizing the powder feeding angle, powder feeding rate, and powder feeding amount of each powder feeding tube, and coordinating with the first preset flow rate of the working gas, it is possible not only to control the time it takes for the raw material powder to pass through different torch regions, but also to ensure that the raw material powder fed by the first powder feeding tube falls into the preset radial outer region of the first torch region, the raw material powder fed by the second powder feeding tube falls into the preset radial outer region of the second torch region, and the raw material powder fed by the third powder feeding tube falls into the entire region of the third torch region. This ensures that the raw material powder is rapidly spheroidized in the high-temperature region of the microwave plasma torch without burning, and that the residence time in the low-temperature region is extended to ensure sufficient heating and spheroidization. This improves energy utilization while ensuring the sphericity and sphericity of the final spherical powder. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0019] Figure 1 This illustration shows a cross-sectional schematic diagram of a microwave plasma powder-making apparatus according to an exemplary embodiment of this application; Figure 2 Show Figure 1 Enlarged view of point A in the middle; Figure 3 A cross-sectional schematic diagram of a microwave plasma torch in an exemplary embodiment of this application is shown; Figure 4 This invention illustrates a flowchart of the steps of a microwave plasma powder preparation method according to an exemplary embodiment of this application. Figure 5 This diagram illustrates the temperature field distribution of a microwave plasma torch in an exemplary embodiment of this application. Figure 6 This document shows an electron microscope image of spherical silicon powder in an exemplary embodiment of this application; Figure 7 This document shows an electron microscope image of spherical titanium alloy powder in an exemplary embodiment of this application; Figure 8 This image shows an electron microscope (EM) image of spherical copper alloy powder in an exemplary embodiment of this application.

[0020] Figure label: 100. Microwave plasma exciter; 200. Plasma delivery pipe; 300. Conductor tube; 310. First quartz tube; 320. Inner conductor tube; 321. Protruding structure; 301. First channel; 400. Vaporization chamber; 401. First powder delivery pipe; 402. Second powder delivery pipe; 403. Second quartz tube; 404. Gas delivery port; 405. Second channel; 406. Inclined conical surface; 500. Reaction chamber; 501. Third powder delivery pipe; 600. Separator and collector; 700. Filter; 810. First flare area; 811. First central area; 812. First peripheral area; 820. Second flare area; 821. Second central area; 822. Second peripheral area; 830. Third flare area. Detailed Implementation

[0021] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided to make this application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0022] Furthermore, the accompanying drawings are merely illustrative diagrams of embodiments of this application and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities.

[0023] This exemplary embodiment first provides a microwave plasma powder-making apparatus, referencing... Figure 1 As shown, the microwave plasma powder-making device includes a microwave plasma exciter 100, a plasma delivery pipe 200, a conductor pipe 300, a vaporization chamber 400, a reaction chamber 500, a separation collector 600, and a filter 700.

[0024] A microwave plasma exciter 100 is installed at one end of the plasma delivery pipe 200, and the other end is sealed. The conductor pipe 300 includes a first quartz tube 310 and an inner conductor pipe 320 coaxially disposed within the first quartz tube 310. The first quartz tube 310 vertically passes through the plasma delivery pipe 200, and both ends of the first quartz tube 310 are open. The gap between the inner wall of the first quartz tube 310 and the outer wall of the inner conductor pipe 320 forms a first channel 301 for the transmission of working gas. A vaporization chamber 400 is coaxially disposed below the first quartz tube 310 and communicates with the first quartz tube 310. The vaporization chamber 400... A first powder feeding pipe 401 and a second powder feeding pipe 402 are arranged sequentially from top to bottom. The lower end of the inner conductor pipe 320 extends into the gasification chamber 400 and is located above the lower end of the first powder feeding pipe 401. A reaction chamber 500 is coaxially arranged below the gasification chamber 400 and communicates with the gasification chamber 400. A third powder feeding pipe 501 is provided in the reaction chamber 500. A filter 700, a separator collector 600, and a reaction chamber 500 are arranged sequentially in the horizontal direction. The separator collector 600 communicates with the reaction chamber 500, and the filter 700 communicates with the separator collector 600. The horizontal direction is perpendicular to the axial direction of the inner conductor pipe 320.

[0025] Among them, the axial direction of the inner conductor tube 320 is as follows: Figure 1 The direction indicated by the middle arrow ab is horizontal. Figure 1 The direction indicated by the middle arrow cd.

[0026] Both the gasification chamber 400 and the reaction chamber 500 are cylindrical. The first powder feeding pipe 401, the second powder feeding pipe 402, and the third powder feeding pipe 501 are staggered around the circumference of the gasification chamber 400. The angles between the first powder feeding pipe 401, the second powder feeding pipe 402, and the third powder feeding pipe 501 and the horizontal direction decrease sequentially, that is, the angle between the third powder feeding pipe 501 and the horizontal direction is smaller than the angle between the second powder feeding pipe 402 and the horizontal direction, and the angle between the second powder feeding pipe 402 and the horizontal direction is smaller than the angle between the first powder feeding pipe 401 and the horizontal direction.

[0027] In the embodiments of this application, microwaves generated by the microwave plasma exciter 100 are conducted to the first quartz tube 310 of the conductor tube 300 via the plasma delivery pipe 200. After excitation and coupling with the inner conductor tube 320 inside the first quartz tube 310, the microwaves generated by the microwave plasma exciter 100 can act on the working gas in the first channel 301, so that a first flare region 810, a second flare region 820, and a third flare region 830 are formed below the conductor tube 300, arranged sequentially from top to bottom with decreasing flare temperatures. Raw material powder is fed into the first flare region 810, the second flare region 820, and the third flare region 830 respectively via the first powder feeding pipe 401 and the second powder feeding pipe 402 on the vaporization chamber 400 and the third powder feeding pipe 501 on the reaction chamber 500, so as to realize multi-dimensional powder feeding and improve the energy utilization rate of the microwave plasma powder making device.

[0028] Below, we will refer to Figure 1 and Figure 2 The various parts of the microwave plasma powder-making apparatus described in this exemplary embodiment will be explained in more detail.

[0029] In one embodiment, reference Figure 2 As shown, a gasification chamber 400 is provided with a through-hole 404. One end of the gasification chamber 404 is connected to the outer wall of the gasification chamber 400, and the other end is connected to the inner wall of the gasification chamber 400. In the height direction of the gasification chamber 400, the gasification chamber 404 is located between the first powder feeding pipe 401 and the second powder feeding pipe 402. The height direction of the gasification chamber 400 is parallel to the axial direction of the inner conductor pipe 320.

[0030] A second quartz tube 403 is provided inside the vaporization chamber 400. The gap between the outer wall of the second quartz tube 403 and the inner wall of the vaporization chamber 400 forms a second channel 405. The second channel 405 is connected to the gas supply port 404 and is used to provide a flow channel for the protective gas.

[0031] The lower end of the first powder feeding tube 401 is located inside the second quartz tube 403, and the lower end of the second powder feeding tube 402 is located below the second quartz tube 403.

[0032] The protective gas can be introduced into the vaporization chamber 400 through the air inlet 404. With the help of the second channel 405 formed between the outer wall of the second quartz tube 403 and the inner wall of the vaporization chamber 400, the protective gas introduced from the air inlet 404 can flow downward along the inner wall of the vaporization chamber 400 through the second channel 405, thereby preventing the raw material powder fed into the vaporization chamber 400 through the first powder feeding pipe 401 and the second powder feeding pipe 402 from adhering to the inner wall of the vaporization chamber 400.

[0033] Optionally, the gasification chamber 400 is provided with multiple air inlets 404, which are evenly spaced along the circumference of the gasification chamber 400. Protective gas is simultaneously introduced into the gasification chamber 400 through the multiple air inlets 404, so that, with the synergistic effect of the second channel 405, an annular airflow channel that adheres to the inner wall of the gasification chamber 400 and flows continuously can be formed within the gasification chamber 400. This more effectively isolates the raw material powder from adhering to the inner wall of the gasification chamber 400, which not only improves the powder yield and powder production capacity of spherical powder but also keeps the inner wall of the gasification chamber 400 smooth.

[0034] In one embodiment, multiple first powder feeding pipes 401, second powder feeding pipes 402, and third powder feeding pipes 501 are provided; multiple first powder feeding pipes 401 are evenly spaced along the circumference of the gasification chamber 400, multiple second powder feeding pipes 402 are evenly spaced along the circumference of the gasification chamber 400, and multiple third powder feeding pipes 501 are evenly spaced along the circumference of the gasification chamber 400.

[0035] Optionally, the first powder feeding tube 401 is provided with 2-8 tubes, the second powder feeding tube 402 is provided with 2-8 tubes, and the third powder feeding tube 501 is provided with 2-8 tubes.

[0036] For example, there are four powder feeding pipes: the first powder feeding pipe 401, the second powder feeding pipe 402, and the third powder feeding pipe 501. In the circumferential direction of the gasification chamber 400, the four first powder feeding pipes 401 are arranged at angles of 0°, 90°, 180°, and 270°; the four second powder feeding pipes 402 are arranged at angles of 30°, 120°, 210°, and 300°; and the four third powder feeding pipes 501 are arranged at angles of 60°, 150°, 240°, and 330°.

[0037] The above configuration enables the microwave plasma powder-making device to construct a multi-dimensional powder feeding structure. This multi-dimensional powder feeding structure consists of multiple first powder feeding pipes 401, multiple second powder feeding pipes 402, and multiple third powder feeding pipes 501 that are distributed at different heights and arranged in a staggered manner around the circumference. This multi-dimensional powder feeding structure can improve the heat utilization rate of the microwave plasma torch and increase the production capacity of the microwave plasma powder-making device.

[0038] In one embodiment, reference Figure 1 As shown, the angle between the first powder feeding pipe 401 and the horizontal direction ranges from 60° to 75°, the angle between the second powder feeding pipe 402 and the horizontal direction ranges from 30° to 60°, and the angle between the third powder feeding pipe 501 and the horizontal direction ranges from 10° to 30°. The horizontal direction is as follows... Figure 1 The direction indicated by the middle arrow cd.

[0039] For example, the first powder feeding pipe 401 has an angle of 75° with the horizontal direction, the second powder feeding pipe 402 has an angle of 60° with the horizontal direction, and the third powder feeding pipe 501 has an angle of 30° with the horizontal direction.

[0040] It should be noted that during the powder feeding process, based on the angles set between the first powder feeding pipe 401, the second powder feeding pipe 402, and the third powder feeding pipe 501 and the horizontal direction, and in conjunction with the powder feeding rate and amount of the first powder feeding pipe 401, the powder feeding rate and amount of the second powder feeding pipe 402, and the powder feeding rate and amount of the third powder feeding pipe 501, it is possible not only to control the raw material powder fed by the first powder feeding pipe 401 to fall into the preset radial outer area of ​​the first flare area 810, the raw material powder fed by the second powder feeding pipe 402 to fall into the preset radial outer area of ​​the second flare area 820, and the raw material powder fed by the third powder feeding pipe 501 to fall into the entire area of ​​the third flare area 830, but also to control the time it takes for the raw material powder to pass through different flare areas, thereby avoiding overheating and volatilization of the raw material powder while ensuring that the raw material powder is fully heated and spheroidized.

[0041] In one embodiment, reference Figure 2 As shown, a protruding structure 321 is provided on the outer periphery of the lower end of the inner conductor tube 320, and an inclined conical surface 406 is provided on the top of the inner wall of the vaporization chamber 400. The inclined conical surface 406 extends along the circumferential direction of the vaporization chamber 400 to form a frustum-shaped cavity within the vaporization chamber 400. The protruding structure 321 is located within the cavity formed by the inclined conical surface 406. This arrangement creates a mechanical constraint between the inner conductor tube 320 and the vaporization chamber 400. This allows the strongest point of the microwave field intensity to shift from the middle height position of the first quartz tube 310 to the bottom of the inner conductor tube 320 under electromagnetic coupling. Consequently, under the excitation of the microwave plasma exciter 100, the working gas introduced from the second channel 405 can be ionized to form a microwave plasma torch.

[0042] It should be noted that by using filter 700 to filter the spherical powder collected by separator 600, impurities and nano-sized powders can be removed, resulting in spherical powder with a median particle size of the target particle size, which is in the micrometer range.

[0043] It should be noted that the specific structure and working principle of the microwave plasma exciter 100, the separator collector 600, and the filter 700 in the above embodiments are all conventional technical means in the field, and will not be described in detail here.

[0044] This example embodiment also provides a microwave plasma powder preparation method, see reference. Figure 1 and Figure 4 As shown, the microwave plasma powder preparation method may include the following steps S101 to S105.

[0045] Step S101: Start the microwave plasma exciter 100 of the microwave plasma powder making device, and use the plasma delivery pipe 200 to conduct the microwave generated by the microwave plasma exciter 100 to the first quartz tube 310 of the conductor tube 300, and couple it with the inner conductor tube 320 inside the first quartz tube 310 after excitation.

[0046] Step S102: Working gas is introduced into the first channel 301 of the conductor tube 300 at a first preset flow rate. Under the excitation of the microwave plasma exciter 100, the working gas forms a microwave plasma torch in the vaporization chamber 400 and reaction chamber 500 below the conductor tube 300. The microwave plasma torch includes a first torch region 810, a second torch region 820 and a third torch region 830 arranged from top to bottom with decreasing torch temperatures.

[0047] Step S103: Raw material powder is fed into the first flare region 810 via the first powder feeding pipe 401 of the vaporization chamber 400 at a first preset powder feeding angle, a first preset powder feeding rate, and a first preset powder feeding amount. Raw material powder is fed into the second flare region 820 via the second powder feeding pipe 402 of the vaporization chamber 400 at a second preset powder feeding angle, a second preset powder feeding rate, and a second preset powder feeding amount. Raw material powder is fed into the third flare region 830 via the third powder feeding pipe 501 of the reaction chamber 500 at a third preset powder feeding angle, a third preset powder feeding rate, and a third preset powder feeding amount, so that the raw material powder is fully vaporized under the action of the microwave plasma flare to obtain vaporized powder.

[0048] Step S104: The gasified powder is fed into the reaction chamber 500 by the blowing force of the working gas, so that the gasified powder is rapidly cooled by the cooling gas in the reaction chamber 500 to obtain solidified spherical powder.

[0049] Step S105: The solidified spherical powder is collected and filtered sequentially by the separator 600 and filter 700 of the microwave plasma powder making device to obtain spherical powder with a median particle size of the target particle size, which is in the micrometer range.

[0050] Among them, the second preset powder feeding angle is greater than the third preset powder feeding angle and less than the first preset powder feeding angle, the second preset powder feeding rate is greater than the third preset powder feeding rate and less than the first preset powder feeding rate, and the second preset powder feeding amount is greater than the first preset powder feeding amount and less than the third preset powder feeding amount.

[0051] It should be noted that the first preset powder feeding angle is the angle between the first powder feeding tube 401 and the horizontal direction, the second preset powder feeding angle is the angle between the second powder feeding tube 402 and the horizontal direction, and the third preset powder feeding angle is the angle between the third powder feeding tube 501 and the horizontal direction; wherein, the horizontal direction is as follows... Figure 1 The direction indicated by the middle arrow cd.

[0052] In the embodiments of this application, microwaves generated by the microwave plasma exciter 100 are conducted to the first quartz tube 310 of the conductor tube 300 via the plasma delivery pipe 200. After excitation and coupling with the inner conductor tube 320 within the first quartz tube 310, the microwaves generated by the microwave plasma exciter 100 can act on the working gas within the first channel 301, thereby forming a first flare region 810, a second flare region 820, and a third flare region 830 arranged sequentially from top to bottom with progressively decreasing flare temperatures below the conductor tube 300. Raw material powder is fed into the first flare region 810, the second flare region 820, and the third flare region 830 respectively via the first powder feeding pipe 401 and the second powder feeding pipe 402 located on the vaporization chamber 400, and the third powder feeding pipe 501 located on the reaction chamber 500, thereby achieving multi-dimensional powder feeding and improving efficiency. The high-energy utilization rate of the microwave plasma powder preparation device is achieved by optimizing the powder feeding angle, feeding rate, and feeding amount of each powder feeding tube, and coordinating with the first preset flow rate of the working gas. This not only controls the time it takes for the raw material powder to pass through different torch regions, but also ensures that the raw material powder fed by the first powder feeding tube 401 falls into the preset radial outer region of the first torch region 810, the raw material powder fed by the second powder feeding tube 402 falls into the preset radial outer region of the second torch region 820, and the raw material powder fed by the third powder feeding tube 501 falls into the entire region of the third torch region 830. This ensures that the raw material powder is rapidly spheroidized in the high-temperature region of the microwave plasma torch without burning, and that the residence time in the low-temperature region is extended to ensure sufficient heating and spheroidization. This improves energy utilization while ensuring the sphericity and sphericity of the final spherical powder.

[0053] Below, we will refer to Figures 1 to 5 The steps of the microwave plasma powder preparation method described in this exemplary embodiment will be explained in more detail.

[0054] In one embodiment, before activating the microwave plasma exciter 100 of the microwave plasma powder-making apparatus in step S101, the microwave power of the microwave plasma exciter 100 is set. For example, the microwave power of the microwave plasma exciter 100 is set to 25 kW.

[0055] In one embodiment, in step S102, the range of the first preset flow rate is 10 m / s-15 m / s. (Reference) Figure 1 As shown, the first flare region 810 is located within the gasification chamber 400, a portion of the second flare region 820 is located within the gasification chamber 400, and another portion is located within the reaction chamber 500, and the third flare region 830 is located within the reaction chamber 500.

[0056] It should be noted that by setting the microwave power to 25kW and the first preset flow rate to a range of 10m / s-15m / s, the microwave plasma torch formed below the conductor tube 300 can occupy the gasification chamber 400 and part of the reaction chamber 500. This is beneficial for subsequent use with a multi-dimensional powder feeding structure to improve the heat utilization rate of the microwave plasma torch.

[0057] For example, when the microwave power is 25kW and the first preset flow rate is 11m / s, a microwave plasma torch with a diameter of 80mm and a length of 700mm can be formed below the conductor tube 300.

[0058] For example, when the microwave power is 25kW and the first preset flow rate is 13m / s, a microwave plasma torch with a diameter of 60mm and a length of 740mm can be formed below the conductor tube 300.

[0059] For example, when the microwave power is 25kW and the first preset flow rate is 15m / s, a microwave plasma torch with a diameter of 90mm and a length of 800mm can be formed below the conductor tube 300.

[0060] In one embodiment, in step S102, the torch temperature range of the first torch region 810 is 4500K-6000K, the torch temperature range of the second torch region 820 is 4000K-5500K, and the torch temperature range of the third torch region 830 is 2000K-4000K.

[0061] It should be noted that by setting the microwave power to 25kW and the first preset flow rate to a range of 10m / s-15m / s, the torch temperatures of the first torch region 810, the second torch region 820, and the third torch region 830 of the microwave plasma torch can meet the above range. This allows for subsequent coordination with multi-dimensional powder feeding structures, powder feeding angles, powder feeding rates, and powder feeding amounts to control the rapid spheroidization of the raw material powder in the high-temperature zone of the microwave plasma torch without over-burning, and to extend the residence time in the low-temperature zone of the microwave plasma torch for sufficient heating and spheroidization.

[0062] In one embodiment, before the raw material powder is fed into the first flare region 810 via the first powder feeding pipe 401 of the gasification chamber 402 at a first preset powder feeding angle, a first preset powder feeding rate, and a first preset powder feeding amount in step S102, the following steps are also included: Protective gas is introduced into the vaporization chamber 400 through the gas inlet 404 at a second preset flow rate. The protective gas flows downward along the inner wall of the vaporization chamber 400 under the guidance of the second quartz tube 403 installed inside the vaporization chamber 400. The second preset flow rate is in the range of 5-10 m / s.

[0063] It should be noted that the reference Figure 1 and Figure 2 As shown, the gap between the outer wall of the second quartz tube 403 and the inner wall of the vaporization chamber 400 forms a second channel 405, which is connected to the gas supply port 404 and is used to provide a flow channel for the protective gas.

[0064] The protective gas is introduced into the vaporization chamber 400 through the air inlet 404 at a second preset flow rate. This allows the protective gas introduced through the air inlet 404 to flow downward along the inner wall of the vaporization chamber 400 via the second channel 405, thereby preventing the raw material powder introduced into the vaporization chamber 400 via the first powder feeding pipe 401 and the second powder feeding pipe 402 from adhering to the inner wall of the vaporization chamber 400.

[0065] Optionally, the gasification chamber 400 is provided with multiple air inlets 404, which are evenly spaced along the circumference of the gasification chamber 400. Protective gas is simultaneously introduced into the gasification chamber 400 through the multiple air inlets 404, so that, with the synergistic effect of the second channel 405, an annular airflow channel that adheres to the inner wall of the gasification chamber 400 and flows continuously can be formed within the gasification chamber 400. This more effectively isolates the raw material powder from adhering to the inner wall of the gasification chamber 400, which not only improves the powder yield and powder production capacity of spherical powder but also keeps the inner wall of the gasification chamber 400 smooth.

[0066] In one embodiment, the range of the first preset flow rate in step S102 is 10m / s-15m / s, the range of the first preset powder feeding rate in step S103 is 8m / s-10m / s, the range of the second preset powder feeding rate is 3m / s-8m / s, and the range of the third preset powder feeding rate is 1m / s-5m / s.

[0067] It should be noted that by setting the first preset powder feeding rate, the second preset powder feeding rate, the third preset powder feeding rate, and the first preset flow rate, the first preset flow rate is coordinated with the high powder feeding rate of the first powder feeding pipe 401, the medium powder feeding rate of the second powder feeding pipe 402, and the low powder feeding rate of the third powder feeding pipe 501. This ensures that the raw material powder fed by the first powder feeding pipe 401 can fall into the first flare area 810, the raw material powder fed by the second powder feeding pipe 402 can fall into the second flare area 820, and the raw material powder fed by the third powder feeding pipe 501 can fall into the third flare area 830.

[0068] Furthermore, in step S103, the first preset powder feeding angle ranges from 60° to 75°, the first preset powder feeding amount ranges from 10g / min to 15g / min, the second preset powder feeding angle ranges from 30° to 60°, the second preset powder feeding amount ranges from 15g / min to 18g / min, the third preset powder feeding angle ranges from 10° to 30°, and the third preset powder feeding amount ranges from 25g / min to 30g / min.

[0069] It should be noted that, based on setting the first preset powder feeding rate, the second preset powder feeding rate, the third preset powder feeding rate, and the first preset flow rate, the first preset powder feeding angle, the second preset powder feeding angle, and the third preset powder feeding angle, as well as the first preset powder feeding amount, the second preset powder feeding amount, and the third preset powder feeding amount, are further set so that the raw material powder fed into the first powder feeding pipe 401 can fall into the preset radial outer region of the first flare region 810, the raw material powder fed into the second powder feeding pipe 402 can fall into the preset radial outer region of the second flare region 820, and the raw material powder fed into the third powder feeding pipe 501 can fall into the entire region of the third flare region 830.

[0070] refer to Figure 3 As shown in the figure, the axial direction of the microwave plasma torch in this embodiment is parallel to the axial direction of the inner conductor tube 320. The first torch region 810, the second torch region 820, and the third torch region 830 are arranged sequentially from top to bottom along the axial direction of the microwave plasma torch. The predetermined radial peripheral region of the first torch region 810 is as follows: Figure 3 The first peripheral region 812 and the second torch region 820 shown in the figure have preset radial peripheral regions as follows: Figure 3 The second outer region 822 is shown in the figure.

[0071] refer to Figure 3 As shown, the axial direction of the first torch region 810 is parallel to the axial direction of the inner conductor tube 320, and the axial direction of the inner conductor tube 320 is as follows: Figure 3 The direction indicated by the middle arrow ab, the radial direction of the first flare region 810 is parallel to the horizontal direction, and the horizontal direction is as follows: Figure 3 The direction indicated by the middle arrow cd. The first flare region 810 includes a first central region 811 and a first peripheral region 812. The radius of the first flare region 810 is denoted as R1. In the radial direction of the first flare region 810, located at... The area within is designated as the first central area 811, located in... The area between R1 and R1 is the first outer perimeter region 812.

[0072] refer to Figure 3As shown, the axial direction of the second torch region 820 is parallel to the axial direction of the inner conductor tube 320, and the axial direction of the inner conductor tube 320 is as follows: Figure 3 The direction indicated by the middle arrow ab, the radial direction of the second torch region 820 is parallel to the horizontal direction, and the horizontal direction is as follows: Figure 3 The direction indicated by the middle arrow cd. The second flare region 820 includes a second central region 821 and a second peripheral region 822. The radius of the second flare region 820 is denoted as R2. In the radial direction of the second flare region 820, located at... The area within is designated as the second central area 821, located in... The area between R2 and R2 is the second outer perimeter region 822.

[0073] It should be noted that, in the microwave plasma torch of this embodiment, the torch temperature gradually decreases along the axial direction of the microwave plasma torch and gradually moves away from the conductor tube 300; and along the radial direction of the microwave plasma torch and from the center outwards. (Reference) Figure 5 The diagram shows the temperature field distribution of the microwave plasma torch. The temperature field range of the first central region 811 is 5500K-6000K, the temperature field range of the first peripheral region 812 is 4500K-5000K, the temperature field range of the second central region 821 is 4000K-5500K, the temperature field range of the second peripheral region 822 is 4000K-4500K, and the temperature field range of the third torch region 830 is 2000K-4000K. It should be noted that, because the first torch region 810 has the highest temperature, it is prone to ablation and volatilization of the raw material powder. Conversely, because the second torch region 820 has a lower temperature and the third torch region 830 has the lowest temperature, the raw material powder fed into the second torch region 820 and the third torch region 830 is prone to insufficient heating, affecting the melting and spheroidization process.

[0074] This application allows the raw material powder falling in the first flare region 810, the second flare region 820, and the third flare region 830 to pass through the microwave plasma flare at different speeds by setting the first preset powder feeding rate, the second preset powder feeding rate, and the third preset powder feeding angle, thereby controlling the time it takes for the raw material powder to pass through different flare regions.

[0075] For example, with a microwave plasma torch length of 1000mm, a first torch region 810 length of 200mm, a second torch region 820 length of 300mm, and a third torch region 830 length of 500mm, if the first preset powder feeding angle is set to 75° and the first preset powder feeding rate is set to 10m / s, then the raw material powder fed through the first powder feeding pipe 401 will take 0.02s to pass through the first torch region 810, 0.03s to pass through the second torch region 820, and 500mm to pass through the third torch region 830. The time for the third flare region 830 is 0.05s; if the second preset powder feeding angle is set to 60° and the second preset powder feeding rate is set to 8m / s, the raw material powder fed through the second powder feeding pipe 402 will take 0.04s to pass through the second flare region 820 and 0.07s to pass through the third flare region 830; if the third preset powder feeding angle is set to 30° and the third preset powder feeding rate is set to 5m / s, the raw material powder fed through the third powder feeding pipe 501 will take 0.2s to pass through the third flare region 830.

[0076] It should be noted that, under the setting of the first preset flow rate, by setting the preset powder feeding angle, preset powder feeding rate, and preset powder feeding amount, it is possible to avoid overheating and volatilization of the raw material powder while ensuring that the raw material powder is fully heated and spheroidized. For example, by setting the first preset powder feeding angle, first preset powder feeding rate, and first preset powder feeding amount, a large-angle and rapid powder feeding is used for the first flare region 810 with the highest temperature, thereby ensuring that the raw material powder fed into the first powder feeding pipe 401 falls into the first peripheral region 812 and is rapidly heated and spheroidized in a short time, avoiding the ablation and volatilization of the raw material powder; by setting the second preset powder feeding angle, second preset powder feeding rate, and second preset powder feeding amount, a relatively smaller powder feeding angle, powder feeding rate, and relatively larger powder feeding amount are used for the second flare region 820 with a lower temperature, thereby ensuring... The raw material powder fed by the second powder feeding tube 402 will fall into the second peripheral region 822, and the time for the raw material powder to pass through the microwave plasma torch will be appropriately extended to ensure that the raw material powder can be fully heated and spheroidized. By setting the third preset powder feeding angle, the third preset powder feeding rate and the third preset powder feeding amount, a small angle and slow speed powder feeding is used for the third torch region 830 with the lowest temperature, thereby ensuring that the raw material powder fed by the third powder feeding tube 501 will fall into the entire region of the third torch region 830, and that the raw material powder has sufficient heating time in the microwave plasma torch, thereby being fully heated and spheroidized.

[0077] As can be seen from the above embodiments, the microwave plasma powder preparation method proposed in this application can not only control the time that the raw material powder passes through different torch regions, but also prevent the raw material powder from falling into the first central region 811 and the second central region 821 and causing raw material ablation. This ensures that the raw material powder is rapidly spheroidized in the high-temperature region of the microwave plasma torch without burning, and that the residence time of the raw material powder in the low-temperature region of the microwave plasma torch is extended so that it is fully heated and spheroidized. This improves energy utilization while ensuring the sphericity and sphericity of the final spherical powder.

[0078] In one embodiment, the reaction chamber 500 is filled with a cooling gas, which is a low-temperature inert gas. In step S104, the gasified powder obtained in step S103 is fed into the reaction chamber 500 by the blowing force of the working gas at a first preset flow rate. The low-temperature inert gas in the reaction chamber 500 rapidly cools the gasified powder. The rapidly cooled gasified powder spheroidizes under the action of surface tension, thereby obtaining solidified spherical powder.

[0079] In one embodiment, the solidified spherical powder obtained in step S104 enters the separation collector 600 and filter 700 sequentially from the reaction chamber 500. Then, in step S105, the solidified spherical powder is collected and filtered sequentially through the separation collector 600 and filter 700 to obtain spherical powder with a median particle size of the target particle size.

[0080] It should be noted that the connection relationships and specific settings of the microwave plasma exciter 100, plasma delivery pipe 200, conductor pipe 300, first quartz tube 310, inner conductor tube 320, vaporization chamber 400, first powder delivery pipe 401, second powder delivery pipe 402, second quartz tube 403, gas delivery hole 404, reaction chamber 500, third powder delivery pipe 501, separator collector 600, and filter 700 in the above-mentioned microwave plasma powder making device have been described, and these structures will not be repeated here.

[0081] The present application will be further illustrated by the following embodiments.

[0082] Example 1 In Example 1, irregular silicon powder with a particle size of 1μm-10μm was selected as the raw material powder for preparing spherical silicon powder, and the median particle size D of the raw material powder was... 50 It is 7.62 μm.

[0083] In Example 1, there are four powder feeding pipes: the first powder feeding pipe 401, the second powder feeding pipe 402, and the third powder feeding pipe 501. In the circumferential direction of the gasification chamber 400, the four first powder feeding pipes 401 are arranged at angles of 0°, 90°, 180°, and 270°, the four second powder feeding pipes 402 are arranged at angles of 30°, 120°, 210°, and 300°, and the four third powder feeding pipes 501 are arranged at angles of 60°, 150°, 240°, and 330°.

[0084] In Example 1, the microwave power is set to 25kW, the first preset flow rate is 11m / s, and the second preset flow rate is 8m / s.

[0085] In Example 1, the first preset powder feeding angle is 60°, the second preset powder feeding angle is 30°, and the third preset powder feeding angle is 10°; the first preset powder feeding rate is 8m / s, the second preset powder feeding rate is 4m / s, and the third preset powder feeding rate is 1m / s; the first preset powder feeding amount is 11g / min, the second preset powder feeding amount is 16g / min, and the third preset powder feeding amount is 26g / min.

[0086] The specific steps of Example 1 are as follows: Step 1: Start the microwave plasma exciter 100 and use the plasma delivery pipe 200 to conduct the microwave generated by the microwave plasma exciter 100 to the first quartz tube 310 of the conductor tube 300, and couple it with the inner conductor tube 320 inside the first quartz tube 310 after excitation.

[0087] Step 2: The working gas is introduced into the first channel 301 of the conductor tube 300 at a flow rate of 11 m / s. The working gas forms a microwave plasma torch with a diameter of 80 mm and a length of 700 mm under the excitation of the microwave plasma exciter 100.

[0088] Step 3: Protective gas is introduced into the vaporization chamber 400 through the gas inlet 404 at a flow rate of 8 m / s.

[0089] Step 4: Raw material powder is fed into the first torch region 810 of the microwave plasma torch via the first powder feeding pipe 401 at a powder feeding angle of 60°, a powder feeding rate of 8m / s, and a powder feeding amount of 11g / min; raw material powder is fed into the second torch region 820 of the microwave plasma torch via the second powder feeding pipe 402 at a powder feeding angle of 30°, a powder feeding rate of 4m / s, and a powder feeding amount of 16g / min; raw material powder is fed into the third torch region 830 of the microwave plasma torch via the third powder feeding pipe 501 at a powder feeding angle of 10°, a powder feeding rate of 1m / s, and a powder feeding amount of 26g / min; the raw material powder fed into the first powder feeding pipe 401, the second powder feeding pipe 402, and the third powder feeding pipe 501 is fully vaporized under the action of the microwave plasma torch to obtain vaporized powder.

[0090] With the above parameters set, the raw material powder fed by the first powder feeding pipe 401 will fall into the first outer periphery region 812 of the first flare region 810, the raw material powder fed by the second powder feeding pipe 402 will fall into the second outer periphery region 822 of the second flare region 820, and the raw material powder fed by the third powder feeding pipe 501 will fall into the entire region of the third flare region 830. This can prevent the raw material powder from overheating and volatilizing while ensuring that the raw material powder is fully heated and spheroidized.

[0091] Step 5: Using the blowing force of the working gas, the gasified powder is sent into the reaction chamber 500, so that the gasified powder is rapidly cooled by the cooling gas in the reaction chamber 500 to obtain solidified spherical silicon powder.

[0092] Step 6: The solidified spherical silicon powder is collected and filtered sequentially by the separator 600 and filter 700 of the microwave plasma powder preparation device to obtain the median particle size D. 50 Spherical silicon powder with a particle size of 6.38 μm (target particle size).

[0093] Example 2 In Example 2, irregular titanium alloy raw material powder with a particle size of 10μm-30μm was selected as the raw material powder for preparing spherical titanium alloy powder. The median particle size D of the raw material powder was... 50 It is 23.8 μm.

[0094] In Example 2, there are six first powder feeding pipes 401, six second powder feeding pipes 402, and six third powder feeding pipes 501. In the circumferential direction of the gasification chamber 400, the six first powder feeding pipes 401 are arranged at angles of 0°, 60°, 120°, 180°, 240°, and 300°, the six second powder feeding pipes 402 are arranged at angles of 20°, 80°, 140°, 200°, 260°, and 320°, and the six third powder feeding pipes 501 are arranged at angles of 40°, 100°, 160°, 220°, 280°, and 340°.

[0095] In Example 2, the microwave power is set to 25kW, the first preset flow rate is 13m / s, and the second preset flow rate is 8m / s.

[0096] In Example 2, the first preset powder feeding angle is 65°, the second preset powder feeding angle is 45°, and the third preset powder feeding angle is 20°; the first preset powder feeding rate is 9m / s, the second preset powder feeding rate is 6m / s, and the third preset powder feeding rate is 1m / s; the first preset powder feeding amount is 13g / min, the second preset powder feeding amount is 17g / min, and the third preset powder feeding amount is 28g / min.

[0097] The specific steps of Example 2 are as follows: Step 1: Start the microwave plasma exciter 100 and use the plasma delivery pipe 200 to conduct the microwave generated by the microwave plasma exciter 100 to the first quartz tube 310 of the conductor tube 300, and couple it with the inner conductor tube 320 inside the first quartz tube 310 after excitation.

[0098] Step 2: The working gas is introduced into the first channel 301 of the conductor tube 300 at a flow rate of 13 m / s. The working gas forms a microwave plasma torch with a diameter of 60 mm and a length of 740 mm under the excitation of the microwave plasma exciter 100.

[0099] Step 3: Protective gas is introduced into the vaporization chamber 400 through the gas inlet 404 at a flow rate of 8 m / s.

[0100] Step 4: Raw material powder is fed into the first torch region 810 of the microwave plasma torch via the first powder feeding pipe 401 at a powder feeding angle of 65°, a powder feeding rate of 9 m / s, and a powder feeding amount of 13 g / min; raw material powder is fed into the second torch region 820 of the microwave plasma torch via the second powder feeding pipe 402 at a powder feeding angle of 45°, a powder feeding rate of 6 m / s, and a powder feeding amount of 17 g / min; raw material powder is fed into the third torch region 830 of the microwave plasma torch via the third powder feeding pipe 501 at a powder feeding angle of 20°, a powder feeding rate of 1 m / s, and a powder feeding amount of 28 g / min; the raw material powder fed into the first powder feeding pipe 401, the second powder feeding pipe 402, and the third powder feeding pipe 501 is fully vaporized under the action of the microwave plasma torch to obtain vaporized powder.

[0101] With the above parameters set, the raw material powder fed by the first powder feeding pipe 401 will fall into the first outer periphery region 812 of the first flare region 810, the raw material powder fed by the second powder feeding pipe 402 will fall into the second outer periphery region 822 of the second flare region 820, and the raw material powder fed by the third powder feeding pipe 501 will fall into the entire region of the third flare region 830. This can prevent the raw material powder from overheating and volatilizing while ensuring that the raw material powder is fully heated and spheroidized.

[0102] Step 5: Using the blowing force of the working gas, the gasified powder is sent into the reaction chamber 500, so that the gasified powder is rapidly cooled by the cooling gas in the reaction chamber 500 to obtain solidified spherical titanium alloy powder.

[0103] Step 6: The solidified spherical titanium alloy powder is collected and filtered sequentially by the separator 600 and filter 700 of the microwave plasma powder preparation device to obtain the median particle size D. 50 The spherical titanium alloy powder has a particle size of 21.2 μm (target particle size).

[0104] Example 3 In Example 3, irregular copper alloy raw material powder with a particle size of 1μm-10μm was selected as the raw material powder for preparing spherical copper alloy powder. The median particle size D of the raw material powder was... 50 It is 6.8μm.

[0105] In Example 3, there are eight first powder feeding pipes 401, eight second powder feeding pipes 402, and eight third powder feeding pipes 501. In the circumferential direction of the gasification chamber 400, the eight first powder feeding pipes 401 are arranged at angles of 0°, 45°, 90°, 135°, 180°, 225°, 270°, and 315°, the eight second powder feeding pipes 402 are arranged at angles of 15°, 60°, 105°, 150°, 195°, 240°, 285°, and 330°, and the eight third powder feeding pipes 501 are arranged at angles of 30°, 75°, 120°, 165°, 210°, 255°, 300°, and 345°.

[0106] In Example 3, the microwave power is set to 25kW, the first preset flow rate is 15m / s, and the second preset flow rate is 8m / s.

[0107] In Example 3, the first preset powder feeding angle is 70°, the second preset powder feeding angle is 60°, and the third preset powder feeding angle is 30°; the first preset powder feeding rate is 10m / s, the second preset powder feeding rate is 8m / s, and the third preset powder feeding rate is 3m / s; the first preset powder feeding amount is 15g / min, the second preset powder feeding amount is 18g / min, and the third preset powder feeding amount is 30g / min.

[0108] The specific steps of Example 3 are as follows: Step 1: Start the microwave plasma exciter 100 and use the plasma delivery pipe 200 to conduct the microwave generated by the microwave plasma exciter 100 to the first quartz tube 310 of the conductor tube 300, and couple it with the inner conductor tube 320 inside the first quartz tube 310 after excitation.

[0109] Step 2: The working gas is introduced into the first channel 301 of the conductor tube 300 at a flow rate of 15 m / s. The working gas forms a microwave plasma torch with a diameter of 90 mm and a length of 800 mm under the excitation of the microwave plasma exciter 100.

[0110] Step 3: Protective gas is introduced into the vaporization chamber 400 through the gas inlet 404 at a flow rate of 8 m / s.

[0111] Step 4: Raw material powder is fed into the first torch region 810 of the microwave plasma torch via the first powder feeding pipe 401 at a powder feeding angle of 70°, a powder feeding rate of 10m / s, and a powder feeding amount of 15g / min; raw material powder is fed into the second torch region 820 of the microwave plasma torch via the second powder feeding pipe 402 at a powder feeding angle of 60°, a powder feeding rate of 8m / s, and a powder feeding amount of 18g / min; raw material powder is fed into the third torch region 830 of the microwave plasma torch via the third powder feeding pipe 501 at a powder feeding angle of 30°, a powder feeding rate of 3m / s, and a powder feeding amount of 30g / min; the raw material powder fed into the first powder feeding pipe 401, the second powder feeding pipe 402, and the third powder feeding pipe 501 is fully vaporized under the action of the microwave plasma torch to obtain vaporized powder.

[0112] With the above parameters set, the raw material powder fed by the first powder feeding pipe 401 will fall into the first outer periphery region 812 of the first flare region 810, the raw material powder fed by the second powder feeding pipe 402 will fall into the second outer periphery region 822 of the second flare region 820, and the raw material powder fed by the third powder feeding pipe 501 will fall into the entire region of the third flare region 830. This can prevent the raw material powder from overheating and volatilizing while ensuring that the raw material powder is fully heated and spheroidized.

[0113] Step 5: Using the blowing force of the working gas, the gasified powder is sent into the reaction chamber 500, so that the gasified powder is rapidly cooled by the cooling gas in the reaction chamber 500 to obtain solidified spherical copper alloy powder.

[0114] Step 6: The solidified spherical copper alloy powder is collected and filtered sequentially by the separator 600 and filter 700 of the microwave plasma powder preparation device to obtain the median particle size D. 50 Spherical copper alloy powder with a target particle size of 6.12 μm.

[0115] refer to Figures 6 to 8 As shown, Figure 6 The image shown is an electron microscope image of the spherical silicon powder in Example 1. It can be seen that the spherical silicon powder has a high sphericity, and the sphericity of the spherical silicon powder can reach more than 85%. Figure 7 The image shown is an electron microscope image of the spherical titanium alloy powder in Example 2. It can be seen that the spherical titanium alloy powder has a high sphericity, and the sphericity of the spherical titanium alloy powder can reach more than 90%. Figure 8 The image shown is an electron microscope image of the spherical copper alloy powder in Example 3. It can be seen that the spherical copper alloy powder has a high sphericity, and the sphericity can reach more than 95%.

[0116] It should also be noted that existing plasma methods typically employ a tail-flame powder feeding method, utilizing only the lower low-temperature flare of the microwave plasma torch. This results in the upper high-temperature flare of the microwave plasma torch being in a dry-burning state, leading to an energy utilization rate of only 20%–30% for the microwave plasma powder preparation device. This application, however, utilizes the entire microwave plasma torch and combines it with a multi-dimensional powder feeding structure. This allows for full utilization of both the upper high-temperature flare and the lower low-temperature flare, significantly improving the energy utilization rate of the microwave plasma powder preparation device. Furthermore, taking irregular silicon powder of 2μm–20μm as the raw material for preparing spherical silicon powder as an example, using the tail-flame powder feeding method, 6 kg–7 kg of spherical silicon powder is produced in 8 hours; while using the microwave plasma powder preparation method proposed in this application, 15 kg–17 kg of spherical silicon powder is produced in 8 hours, increasing the production capacity by 140%.

[0117] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein.

Claims

1. A microwave plasma powder preparation method, characterized in that, include: The microwave plasma exciter of the microwave plasma powder making device is activated, and the microwaves generated by the microwave plasma exciter are conducted to the first quartz tube of the conductor tube through the plasma delivery pipe, and then coupled with the inner conductor tube inside the first quartz tube after excitation. Working gas is introduced into the first channel of the conductor tube at a first preset flow rate. Under the excitation of the microwave plasma exciter, the working gas forms a microwave plasma torch in the vaporization chamber and reaction chamber below the conductor tube. The microwave plasma torch includes a first torch region, a second torch region, and a third torch region arranged from top to bottom with torch temperatures decreasing sequentially. Raw material powder is fed into the first flare area through the first powder feeding pipe of the vaporization chamber at a first preset powder feeding angle, a first preset powder feeding rate, and a first preset powder feeding amount. Raw material powder is fed into the second flare area through the second powder feeding pipe of the vaporization chamber at a second preset powder feeding angle, a second preset powder feeding rate, and a second preset powder feeding amount. Raw material powder is fed into the third flare area through the third powder feeding pipe of the reaction chamber at a third preset powder feeding angle, a third preset powder feeding rate, and a third preset powder feeding amount. This allows the raw material powder to be fully vaporized under the action of the microwave plasma flare to obtain vaporized powder. The working gas is used to blow the gasified powder into the reaction chamber, so that the gasified powder is rapidly cooled by the cooling gas in the reaction chamber to obtain solidified spherical powder. The solidified spherical powder is collected and filtered sequentially by the separator and filter of the microwave plasma powder making device to obtain spherical powder with a median particle size of the target particle size. Wherein, the second preset powder feeding angle is greater than the third preset powder feeding angle and less than the first preset powder feeding angle, the second preset powder feeding rate is greater than the third preset powder feeding rate and less than the first preset powder feeding rate, and the second preset powder feeding amount is greater than the first preset powder feeding amount and less than the third preset powder feeding amount.

2. The microwave plasma powder preparation method according to claim 1, characterized in that, Before the raw material powder is fed into the first flare area via the first powder feeding pipe through the gasification chamber at a first preset powder feeding angle, a first preset powder feeding rate, and a first preset powder feeding amount, the process further includes: Protective gas is introduced into the vaporization chamber through the gas inlet at a second preset flow rate. The protective gas flows downward along the inner wall of the vaporization chamber under the guidance of the second quartz tube installed in the vaporization chamber.

3. The microwave plasma powder preparation method according to claim 1, characterized in that, The first preset flow rate is in the range of 10m / s-15m / s, the first preset powder feeding rate is in the range of 8m / s-10m / s, the second preset powder feeding rate is in the range of 3m / s-8m / s, and the third preset powder feeding rate is in the range of 1m / s-5m / s.

4. The microwave plasma powder preparation method according to claim 3, characterized in that, The first preset powder feeding angle ranges from 60° to 75°, the first preset powder feeding amount ranges from 10g / min to 15g / min, the second preset powder feeding angle ranges from 30° to 60°, the second preset powder feeding amount ranges from 15g / min to 18g / min, the third preset powder feeding angle ranges from 10° to 30°, and the third preset powder feeding amount ranges from 25g / min to 30g / min.

5. The microwave plasma powder preparation method according to claim 1, characterized in that, The torch temperature range of the first torch region is 4500K-6000K, the torch temperature range of the second torch region is 4000K-5500K, and the torch temperature range of the third torch region is 2000K-4000K.

6. The microwave plasma powder preparation method according to claim 1, characterized in that, The first flare area is located in the gasification chamber, a portion of the second flare area is located in the gasification chamber and another portion is located in the reaction chamber, and the third flare area is located in the reaction chamber.

7. A microwave plasma powder-making device, characterized in that, include: A plasma delivery pipeline, wherein a microwave plasma exciter is provided at one end of the plasma delivery pipeline and the other end is sealed; The conductor tube includes a first quartz tube and an inner conductor tube coaxially disposed inside the first quartz tube. The first quartz tube passes vertically through the plasma delivery pipe. Both ends of the first quartz tube are open. The gap between the inner wall of the first quartz tube and the outer wall of the inner conductor tube forms a first channel for the transmission of working gas. A vaporization chamber is coaxially disposed below the first quartz tube and communicates with the first quartz tube. The vaporization chamber is provided with a first powder feeding pipe and a second powder feeding pipe from top to bottom. The lower end of the inner conductor tube extends into the vaporization chamber and is located above the lower end of the first powder feeding pipe. The reaction chamber is coaxially disposed below the gasification chamber and communicates with the gasification chamber. The reaction chamber is equipped with a third powder feeding pipe. A separator and a filter are arranged sequentially in a horizontal direction, the filter, the separator and the reaction chamber are connected to the reaction chamber, and the filter is connected to the separator and the horizontal direction is perpendicular to the axial direction of the inner conductor tube. The first powder feeding pipe, the second powder feeding pipe, and the third powder feeding pipe are arranged in a staggered manner along the circumference of the gasification chamber, and the angles between the first powder feeding pipe, the second powder feeding pipe, and the third powder feeding pipe and the horizontal direction decrease sequentially.

8. The microwave plasma powder-making apparatus according to claim 7, characterized in that, The gasification chamber is provided with an air delivery hole, which is located between the first powder delivery pipe and the second powder delivery pipe. A second quartz tube is provided in the vaporization chamber. The gap between the outer wall of the second quartz tube and the inner wall of the vaporization chamber forms a second channel, which is connected to the air delivery hole.

9. The microwave plasma powder-making apparatus according to claim 7, characterized in that, The angle between the first powder feeding tube and the horizontal direction is in the range of 60°-75°, the angle between the second powder feeding tube and the horizontal direction is in the range of 30°-60°, and the angle between the third powder feeding tube and the horizontal direction is in the range of 10°-30°.

10. The microwave plasma powder-making apparatus according to claim 7, characterized in that, Multiple first powder feeding pipes, multiple second powder feeding pipes, and multiple third powder feeding pipes are provided. Multiple first powder feeding pipes are evenly spaced along the circumference of the gasification chamber, multiple second powder feeding pipes are evenly spaced along the circumference of the gasification chamber, and multiple third powder feeding pipes are evenly spaced along the circumference of the gasification chamber.

Images