A metal vapor quenching nucleation powder formation device and a particle size control method

Abstract

This invention discloses a metal vapor quenching nucleation powder-forming device and a particle size control method. The outlet of the nucleation tube is connected to a quenching condenser, which includes a powder-forming chamber, a gas cooling pipe located inside the powder-forming chamber, and a second water-cooled layer located on the outer wall of the powder-forming chamber. The temperature inside the powder-forming chamber can be controlled by controlling the temperature of the cooling water in the second water-cooled layer and the state of gas ejection from the gas cooling pipe. When the nucleated metal vapor enters the powder-forming chamber, it will quickly diffuse into the powder-forming chamber and fully mix and contact with the cooling gas, so that the metal particles in the powder-forming chamber are rapidly cooled. The second water-cooled layer and the gas cooling pipe on the outer wall of the powder-forming chamber, combined inside and out, can quickly control the temperature at various locations inside the powder-forming chamber, preventing the metal particles from continuing to grow or agglomerate. The temperature inside the powder-forming chamber is controlled by introducing cooling water at different temperatures into the second water-cooled layer, gaseous cooling media at different temperatures into the gas cooling pipe, and gaseous cooling media at different flow rates into the gas cooling pipe.

Description

Technical Field

[0001] This invention belongs to the field of metal vapor powder forming apparatus, and particularly relates to a metal vapor quenching nucleation powder forming apparatus and a particle size control method. Background Technology

[0002] Physical vapor deposition (PVD) is a clean and efficient technology for preparing ultrafine metal powders, which has emerged in recent years. In particular, plasma PVD has attracted considerable attention in this field. This process uses excited-state plasma as a heat source, reaching temperatures up to 10,000°C, enabling most refractory metals to vaporize into atomic gases under normal pressure. The metal vapor is then rapidly cooled to form ultrafine metal powders. The entire process is completed in an inert gas environment, with no exhaust gas or wastewater emissions and no introduction of other impurities. Furthermore, the desired particle size of the nickel powder can be obtained by adjusting process parameters. The prepared metal powders exhibit controllable particle size, high purity, good sphericity, smooth surface, and good dispersibility. PVD has become the most commonly used method for producing ultrafine metal powders.

[0003] In the preparation of refractory metal ultrafine powders using the physical vapor deposition method, the metal vapor needs to be cooled to a certain temperature within a very short time in order to cool the vapor into metal particles within a specific size range. However, in practice, after the metal vapor exits the crucible, a brief atomic nucleation process is required. This process is extremely short, and to prevent the nucleated particles from growing excessively, the temperature needs to be cooled to below a certain level within a very short time to inhibit excessive powder growth and agglomeration. However, the nucleation and growth processes of atomized metal vapor are often very difficult to control due to limitations in the structure of commonly used equipment. In particular, the temperature control of the metal vapor powdering process is often insufficient, as the temperature cannot be rapidly reduced to the required level. This results in simultaneous nucleation, growth, and cooling of particles, easily leading to undesirable products such as excessive particle growth, inconsistent particle size, agglomeration, and even particle aggregation. This is because current equipment still uses water-cooled jackets for temperature control. For example, a metal vapor nucleation device for preparing ultrafine powder materials using a physical vapor phase method, as described in Chinese utility model patent document CN216421070U, uses a jacketed shell structure and insulation structure to control the cooling inside the nucleation structure and control the temperature range to ensure successful metal vapor nucleation. However, because its method of temperature control and cooling rate is singular, it is difficult to cool the powder to a certain temperature in a very short time to inhibit excessive growth and agglomeration. Summary of the Invention

[0004] The purpose of this invention is to provide a metal vapor rapid cooling nucleation powder forming device that enables rapid nucleation of metal vapor and rapid cooling to a certain temperature, as well as a method for controlling the particle size of the powder.

[0005] The technical solution adopted in this invention is as follows:

[0006] A metal vapor quenching nucleation powder-forming device includes a nucleation tube with an inlet and an outlet at its two ends. The nucleation tube includes an inner pipe and a water-cooling layer on the outer wall of the inner pipe. The outlet of the nucleation tube is connected to a quenching condenser, which includes a powder-forming chamber, a gas cooling pipe inside the powder-forming chamber, and a water-cooling layer on the outer wall of the powder-forming chamber. The nucleation tube communicates with the inside of the powder-forming chamber. The powder-forming chamber is connected to an outlet pipe, which includes an inner pipe and a water-cooling layer on the outer wall of the inner pipe. The gas cooling pipe has an inlet that extends to the outside of the powder-forming chamber, and gas nozzles are evenly distributed on the gas cooling pipe. The powder-forming chamber is bullet-shaped, with a cylindrical structure at the end closest to the nucleation tube and an arc-shaped funnel structure at the end closest to the outlet pipe. The gas cooling pipes are evenly and parallelly arranged inside the powder-forming chamber along the material flow direction, and the parallel cooling pipes inside the powder-forming chamber are connected sequentially by arc-shaped pipes.

[0007] A further technical solution is that an insulation layer is provided on the outer wall of the water-cooled layer, which is a ceramic felt insulation layer or a carbon felt insulation layer.

[0008] A further technical solution involves the following: the inner pipe of the nucleating tube is a funnel-shaped pipe with a large inlet and a small outlet; the inner pipe, insulation layer, and water-cooling layer of the nucleating tube are coaxial; the ratio of the outer diameter A of the inner pipe to the outer diameter B of the insulation layer on the same cross section is 1:1~4; the ratio of the outer diameter A of the inner pipe to the outer diameter C of the water-cooling layer on the same cross section is 1:1~15; the ratio of the inner diameter of the inlet to the inner diameter of the outlet at both ends of the nucleating tube is 1:1~2; the ratio of the length D of the nucleating tube to the length E of the powder-forming chamber of the quench condenser is 1:0.5~50; the ratio of the average diameter of the nucleating tube to the length D of the nucleating tube is 1:1~50; and the ratio of the minimum inner diameter Amin of the nucleating tube to the maximum inner diameter G of the powder-forming chamber of the quench condenser is 1:1~30.

[0009] A further technical solution involves having more than three parallel gas cooling pipes arranged inside the powder forming chamber.

[0010] A further technical solution is that the gas cooling pipe has a double-layer pipe structure, including an inner pipe and an outer pipe. The inner pipe contains a water-cooled layer and a gas flow layer between the outer and inner pipes. The gas nozzles are located on the surface of the outer pipe. The arc of the gas nozzles on the outer pipe corresponds to the center angle of the outer circle of the gas flow layer, which is 15°~45°. The ratio of the inner diameter K of the water-cooled layer to the outer diameter H of the gas flow layer is 1:1~4. There are 2-4 gas nozzles in the same cross section of the outer pipe of the gas flow layer along the circumferential direction, and the total number of gas nozzles is 30~200.

[0011] A further technical solution involves making the connection between the nucleation tube and the powder formation chamber funnel-shaped.

[0012] A further technical solution involves introducing metal vapor into the inlet of the nucleation tube in a metal vapor quenching nucleation powder forming device as described in claim 7. The particle size of the powder is controlled by changing the temperature and cooling rate inside the powder forming chamber. Specifically, there are two ways to change the temperature and cooling rate inside the powder forming chamber: First, by introducing cooling water at different temperatures into the water-cooling layer, introducing gaseous cooling media at different temperatures into the gas cooling pipe, and introducing gaseous cooling media at different flow rates into the gas cooling pipe to control the temperature inside the powder forming chamber; Second, by adjusting the ratio of the outer diameter A of the inner pipe to the outer diameter B of the insulation layer, the ratio of the outer diameter A of the inner pipe to the outer diameter C of the water-cooling layer, the ratio of the inner diameter of the inlet to the inner diameter of the outlet at both ends of the nucleation tube, the ratio of the length D of the nucleation tube to the length E of the powder forming chamber of the quenching powder condenser, the ratio of the average diameter of the nucleation tube to the length D of the nucleation tube, and the minimum inner diameter A of the nucleation tube. min The ratio of the maximum inner diameter G of the powder forming chamber of the condenser 2, the number of gas nozzles, the angle of the outer circle center of the gas flow layer corresponding to the arc of the gas nozzle on the outer tube, and the ratio of the inner diameter K of the water cooling layer of the gas cooling pipe to the outer diameter H of the gas flow layer.

[0013] A further technical solution is that the gaseous cooling medium is nitrogen, argon, helium, hydrogen, or a mixture of two of the above gases.

[0014] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0015] The nucleation tube consists of an inner pipe and a water-cooled layer on the outer wall of the inner pipe. By adjusting the temperature of the cooling water in the water-cooled layer, the nucleation rate can be controlled.

[0016] The outlet of the nucleation tube is connected to the condenser, and the temperature in the powder forming chamber can be controlled by adjusting the temperature of the cooling water in the second water-cooled layer.

[0017] The powder forming chamber is shaped like a bullet casing, and the gas cooling pipes inside the powder forming chamber are all parallel to the flow direction of the material, which conforms to the principles of fluid mechanics. This can reduce the residual loss of ultrafine metal powder inside the powder forming chamber and on the pipes, and improve the yield of metal powder.

[0018] The inner channel of the nucleation tube is a funnel-shaped channel with a large inlet and a small outlet, which conforms to the principles of fluid dynamics. It accelerates the flow speed of the material in the channel along the flow direction, which to a certain extent makes the atomic nucleation more uniform. Compared with the straight cylinder type, it can reduce the atomic nucleation time and reduce the probability of the generation of large metal particles.

[0019] Gas nozzles are evenly distributed on the gas cooling pipe, through which an inert gaseous cooling medium is introduced. When the nucleated metal vapor enters the powder forming chamber, it quickly diffuses into the chamber and fully mixes and contacts with the low-temperature inert gaseous cooling medium ejected from the gas cooling pipe to exchange heat, thus rapidly cooling the metal particles in the powder forming chamber. The water-cooled layer on the outer wall of the powder forming chamber and the gas cooling pipe work together to quickly control the temperature at various locations within the powder forming chamber, preventing the metal particles from continuing to grow or agglomerate. The particle size range of the metal particles can be controlled within a certain range, resulting in faster powder forming and more uniform particle size. Compared with the traditional single temperature control method, this method can enable the metal vapor to nucleate rapidly and cool quickly to a certain temperature.

[0020] Moreover, the airflow formed by the inert gaseous cooling medium ejected from the gas cooling pipe can further disperse the nucleated metal vapor entering the powder forming chamber, making it easier to cool down the nucleated metal vapor, further preventing the metal particles from continuing to grow or agglomerate, resulting in more uniform particle size of the powder.

[0021] The particle size of the powder is controlled by changing the temperature and cooling rate inside the powder forming chamber. Specifically, the temperature inside the powder forming chamber is controlled by introducing cooling water at different temperatures into the second water-cooling layer, gaseous cooling media at different temperatures into the gas cooling pipe, or gaseous cooling media at different flow rates into the gas cooling pipe. Alternatively, the temperature or cooling rate inside the powder forming chamber can be controlled by changing the component size ratio. Through these multiple temperature control methods, the range of temperature control and the cooling rate are wider and faster than traditional methods. This can effectively enable metal vapor to rapidly nucleate and grow into ultrafine metal powder with a certain particle size range, effectively reducing the generation of large particles and particle agglomeration, and reducing product loss inside the equipment. It is suitable for batch continuous production. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0023] Figure 2 This is a schematic diagram of the arrangement structure of the gas cooling pipe described in this invention;

[0024] Figure 3 This is a schematic diagram of the structure of the gas cooling pipe described in this invention;

[0025] Figure 4 This is a schematic diagram of the structure of the rapid cooling nucleation powder forming device described in this invention;

[0026] Figure 5 This is a schematic diagram of the connection route of the gas cooling pipe described in this invention;

[0027] Figure 6 This is a schematic diagram of the connection route of the gas cooling pipe described in this invention from another perspective;

[0028] Figure 7 This is a schematic diagram of the powder forming chamber described in this invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0030] like Figures 1-7 As shown.

[0031] Example 1

[0032] A metal vapor quenching nucleation powder forming device is characterized by comprising a nucleation tube 1, with an inlet 4 and an outlet 5 at its two ends, respectively. The nucleation tube 1 includes an inner pipe 11 and a water-cooling layer 13 located on the outer wall of the inner pipe 11. The outlet of the nucleation tube 1 is connected to a quenching condenser 2. The quenching condenser 2 includes a powder forming chamber 22, a gas cooling pipe 21 located inside the powder forming chamber 22, and a water-cooling layer 23 located on the outer wall of the powder forming chamber 22. The nucleation tube 1 is connected to the inside of the powder forming chamber 22. The powder forming chamber 22 is connected to an outlet pipe 3. The outlet pipe 3 includes an inner pipe 32 and a water-cooling layer 31 located on the outer wall of the inner pipe 32. The gas cooling pipe 21 has an air inlet 6, which extends to the outside of the powder forming chamber 22. Gas nozzles 213 are evenly distributed on the gas cooling pipe 21. The powder forming chamber 22 is shaped like a bullet casing. The end closer to the nucleation tube 1 is a cylindrical structure, and the end closer to the discharge tube 3 is an arc-shaped funnel structure. The gas cooling tubes 21 are evenly and parallelly arranged inside the powder forming chamber 22 along the material flow direction. The parallel gas cooling tubes 21 inside the powder forming chamber 22 are connected in sequence through arc-shaped pipes.

[0033] In use, the inner pipe 32 of the discharge pipe 3 is connected in sequence to the existing gas-solid separation, powder collection device, and blower. Metal vapor is introduced into the inlet 4 of the nucleation tube 1 in a metal vapor rapid cooling nucleation powder forming device. The particle size of the powder is controlled by changing the temperature and cooling rate inside the powder forming chamber 22. Specifically, the temperature inside the powder forming chamber is controlled by introducing cooling water at different temperatures into the water-cooled layer 23, gaseous cooling media at different temperatures into the gas cooling pipe 21, or gaseous cooling media at different flow rates into the gas cooling pipe 21. Alternatively, the temperature inside the powder forming chamber can be controlled by changing the component size ratio. The inert gaseous cooling medium in the gas cooling pipe 21 is nitrogen, argon, helium, hydrogen, or a mixture of two of these gases. The number of gas nozzles 213 can be changed by replacing the gas cooling pipes. Water-cooled layer 13, water-cooled layer 23, and water-cooled layer 31 are all water-cooled jackets.

[0034] The outlet of the nucleation tube 1 is connected to the quench condenser 2. The quench condenser 2 includes a powder forming chamber 22, a gas cooling pipe 21 located inside the powder forming chamber 22, and a water cooling layer 23 located on the outer wall of the powder forming chamber 22. The temperature inside the powder forming chamber 22 can be controlled by controlling the temperature of the cooling water in the water cooling layer 23.

[0035] The gas cooling pipe 21 has an air inlet 6 that extends to the outside of the powder forming chamber 22. Gas nozzles 213 are evenly distributed on the gas cooling pipe 21. An inert gaseous cooling medium is introduced into the gas cooling pipe 21. When the nucleated metal vapor enters the powder forming chamber 22, it will quickly diffuse into the powder forming chamber 22 and fully mix and contact with the low-temperature inert gaseous cooling medium sprayed from the gas cooling pipe 21 to exchange heat, so that the metal particles in the powder forming chamber 22 are rapidly cooled. The water-cooled layer 23 on the outer wall of the powder forming chamber 22 and the gas cooling pipe 21, together, can quickly control the temperature at various locations in the powder forming chamber 22, prevent the metal particles from continuing to grow or agglomerate, control the particle size range of the metal particles within a certain range, and achieve faster powder forming speed and uniform particle size. Compared with the traditional single temperature control method, this method can enable the metal vapor to nucleate quickly and cool rapidly to a certain temperature.

[0036] The airflow formed by the inert gaseous cooling medium ejected from the gas cooling pipe 21 can further disperse the nucleated metal vapor that enters the powder forming chamber 22, making it easier to cool down the nucleated metal vapor and further preventing the metal particles from continuing to grow or agglomerate, resulting in more uniform particle size of the powder.

[0037] Specifically, the temperature of the water-cooled layer 23, the temperature of the gaseous cooling medium in the gas cooling pipe 21, and the flow rate of the gaseous cooling medium are adjusted to control the temperature and cooling rate inside the powder chamber 22. Alternatively, the temperature and cooling rate inside the powder chamber can be controlled by changing the component size ratio. Compared with traditional methods, the temperature control range and cooling rate are wider and faster. This can effectively enable metal vapor to rapidly nucleate and grow into ultrafine metal powder with a certain particle size range, effectively reducing the generation of large particles and particle agglomeration, and reducing product loss inside the equipment. It is suitable for batch continuous production.

[0038] An insulation layer 12 is provided on the outer wall of the water-cooled layer 13 to prevent heat loss and further ensure temperature control. The metal gas nucleation tube 1 includes an inner pipe 11, an insulation layer 12, and a water-cooled layer 13. The nucleation rate can be controlled by controlling the thickness of these three components. The insulation layer 12 is a ceramic felt insulation layer, a carbon felt insulation layer, or other high-temperature resistant insulation material.

[0039] The inner pipe 11 of the nucleation tube 1 is a funnel-shaped pipe with a large inlet 4 and a small outlet 5, which conforms to the principles of fluid dynamics. It accelerates the flow speed of the material in the channel along the flow direction, which makes the atomic nucleation more uniform to a certain extent. Compared with the straight cylinder type, it can reduce the atomic nucleation time and reduce the probability of generating large metal particles.

[0040] The inner pipe, insulation layer, and water-cooling layer of nucleating tube 1 are coaxial. On the same cross-section, the ratio of the outer diameter A of the inner pipe to the outer diameter B of the insulation layer is 1:1~4, and the ratio of the outer diameter A of the inner pipe to the outer diameter C of the water-cooling layer is 1:1~15. The ratio of the inner diameter of the inlet to the inner diameter of the outlet at both ends of the nucleating tube is 1:1~2. The ratio of the length D of the nucleating tube to the length E of the powder-forming chamber of the quench condenser is 1:0.5~50, the ratio of the average diameter of the nucleating tube to its length D is 1:1~50, and the ratio of the minimum inner diameter Amin of the nucleating tube to the maximum inner diameter G of the powder-forming chamber of the quench condenser 2 is 1:1~30. By adjusting the above component size ratios, the temperature and cooling rate within the powder-forming chamber can be controlled, and the airflow velocity within the entire device can also be adjusted. If the nucleation tube 1 is too long, it will cause the metal nucleation to be too large, resulting in large powder particles. If the inner diameter of the powder forming chamber 22 is too large, it will cause the metal vapor to be unable to diffuse evenly into the forming chamber, resulting in a wide distribution of powder particle size.

[0041] The number of parallel gas cooling pipes inside the powder forming chamber is greater than 3.

[0042] The gas cooling pipe has a double-layer structure, consisting of an inner pipe and an outer pipe. The inner pipe contains a water-cooled layer, and the outer pipe is separated from the inner pipe by a gas flow layer. Gas nozzles are located on the surface of the outer pipe, and the curvature of the gas nozzles on the outer pipe corresponds to an angle of 15° to 45° around the center of the outer circle of the gas flow layer. The ratio of the inner diameter K of the water-cooled layer to the outer diameter H of the gas flow layer is 1:1 to 4. The outer pipe 8 of the gas flow layer has 2-4 gas nozzles at the same cross-section along the circumferential direction, with a total number of 30 to 200 nozzles. Adjusting the dimensional ratios of these components allows control of the temperature inside the powder forming chamber. If the outer diameter of the gas flow layer 211 is too large, insufficient gas cooling can easily occur, resulting in a gas temperature that is not low enough to rapidly cool the metal.

[0043] The powder-forming chamber 22 is bullet-shaped, with a cylindrical structure at the end near the metal gas nucleation tube 1 and an arc-shaped funnel structure at the end near the discharge pipe 3. This conforms to fluid dynamics principles, reducing residual losses of ultrafine metal powder inside the powder-forming chamber 22 and on the pipes, and improving the yield of metal powder. The gas cooling pipe 21 has a double-layer pipe structure, including an inner pipe 7 and an outer pipe 8. The inner pipe 7 contains a water-cooled layer 212, and the outer pipe 8 is connected to the inner pipe 7 by a gas flow layer 211. The gas nozzle 213 is located on the outer pipe 8, which can further control the temperature of the water-cooled layer 212 and the temperature of the inert gas cooling medium in the gas flow layer 211.

[0044] The connection between the nucleation tube 1 and the powder forming chamber 22 is funnel-shaped, which facilitates the rapid diffusion of the nucleation metal vapor into the powder forming chamber 22 after it enters the chamber, and it fully mixes and contacts with the ejected low-temperature inert gas to exchange heat.

[0045] Water cooling layers 1, 23, 31, and 4 (212) are connected to circulating water cooled by an external heat exchanger. The temperature of the circulating water can be adjusted by the heat exchanger. Gas is introduced into the gas cooling pipe 21. When the external blower is turned on, the metal gas evaporated from the high-temperature evaporator at the front end enters the nucleation pipe 1 under the carry-on gas. Metal atoms accumulate and nucleate in the nucleation pipe 1 and then enter the rapid condenser. After nucleation, the metal particles further grow in the powdering chamber 22. At the same time, they fully contact and mix with the cooling gas ejected from the gas nozzle 213 on the gas flow layer 211 of the gas cooling pipe 21. The cooling gas is then mixed with the cooling gas ejected from the gas flow layer 211 of the gas cooling pipe 21. The temperature is rapidly reduced to 50-200℃, and the temperature is detected by a temperature sensor or infrared thermometer installed at the discharge pipe 3. This causes the metal powder to stop growing at the rear end of the powder forming chamber, preventing it from nucleating into large particles or agglomerating into large powder clumps. The powder is then formed into ultrafine metal powder with a certain particle size range. By calibrating the required metal powder particle size through experiments, the temperature of the cooling water in the water-cooled layer 23, the temperature of the gaseous cooling medium introduced into the gas cooling pipe 21, and the flow rate of the gaseous cooling medium introduced into the gas cooling pipe 21 can be correlated. Alternatively, the required metal powder particle size can be correlated with the component size ratio. This allows for the production of metal powder with different particle sizes.

[0046] In Example 2, based on Example 1, the ratio of the inner diameter K of the water-cooled layer of the gas cooling pipe 21 to the outer diameter H of the gas flow layer 211 is 1:3. Three gas nozzles 213 are opened circumferentially at the same cross-section position on the outer pipe 8 of the gas flow layer 211, for a total of 270 gas nozzles 213. The inner pipe 11, insulation layer 12, and water-cooled layer 13 of the nucleating pipe 1 are coaxial pipes. On the same cross-section, the ratio of the outer diameter A of the inner pipe 11 to the outer diameter B of the insulation layer 12 is 1:1.1, and the ratio of the outer diameter A of the inner pipe 11 to the outer diameter C of the water-cooled layer is 1:3. The ratio of the inner diameter of the inlet 4 to the inner diameter of the outlet 5 at both ends of the nucleating pipe 1 is 1:1.5. The ratio of the length D of nucleating tube 1 to the length E of the powder-forming chamber 22 of the quench condenser 2 is 1:20; the ratio of the average diameter of nucleating tube 1 to its length D is 1:5; and the ratio of the minimum inner diameter Amin of nucleating tube 1 to the maximum inner diameter G of the powder-forming chamber 22 of the quench condenser 2 is 1:10. Circulating cooling water cooled by an external heat exchanger is introduced into the pipes of water-cooled layer 13, water-cooled layer 23, water-cooled layer 31, and water-cooled layer 4 212. The cooling water temperature in water-cooled layer 23 is controlled to be below 40℃, and the cooling water temperature in water-cooled layer 4 212 is controlled to be 30℃. An inert gaseous cooling medium is introduced into the gaseous cooling medium pipe 21, with the input temperature controlled to be 30℃ and the flow rate controlled to be 100. / h, turn on the external blower, and the metal vapor enters the device from the feed pipe of the inner pipe 11 of the nucleation tube 1 under the action of airflow. After being cooled and nucleated by the nucleation tube 1, it enters the powder forming chamber 22 and is fully mixed with the inert gaseous cooling medium sprayed from the gas nozzle 213. The temperature detected by the temperature sensor or infrared thermometer set at the discharge pipe 3 is rapidly cooled to below 160°C, so that the metal particles cannot continue to nucleate into large particles or agglomerate into large powder clumps, thus producing metal powder with a diameter of less than 100nm.

[0047] In Example 3, based on Example 1, the ratio of the inner diameter K of the water-cooled layer of the gas cooling pipe 21 to the outer diameter H of the gas flow layer 211 is 1:3. Three gas nozzles 213 are opened circumferentially at the same cross-section position on the outer pipe 8 of the gas flow layer 211, for a total of 270 gas nozzles 213. The inner pipe 11, insulation layer 12, and water-cooled layer 13 of the nucleating pipe 1 are coaxial pipes. On the same cross-section, the ratio of the outer diameter A of the inner pipe 11 to the outer diameter B of the insulation layer 12 is 1:1.1, and the ratio of the outer diameter A of the inner pipe 11 to the outer diameter C of the water-cooled layer is 1:3. The ratio of the inner diameter of the inlet 4 to the inner diameter of the outlet 5 at both ends of the nucleating pipe 1 is 1:1.5. The ratio of the length D of nucleating tube 1 to the length E of the powder-forming chamber 22 of the quench condenser 2 is 1:20; the ratio of the average diameter of nucleating tube 1 to its length D is 1:5; and the ratio of the minimum inner diameter Amin of nucleating tube 1 to the maximum inner diameter G of the powder-forming chamber 22 of the quench condenser 2 is 1:10. Circulating cooling water cooled by an external heat exchanger is introduced into the pipes of water-cooled layer 13, water-cooled layer 23, water-cooled layer 31, and water-cooled layer 4 212. The cooling water temperature in water-cooled layer 23 is controlled below 50℃, and the cooling water temperature in water-cooled layer 4 212 is controlled between 40-50℃. An inert gaseous cooling medium is introduced into the gaseous cooling medium pipe 21, with the input temperature controlled at 40℃ and the flow rate controlled at 70. / h, turn on the external blower, and the metal vapor enters the device from the feed pipe of the inner pipe 11 of the nucleation tube 1 under the action of airflow. After being cooled and nucleated by the nucleation tube 1, it enters the powder forming chamber 22 and is fully mixed with the inert gaseous cooling medium sprayed from the gas nozzle 213. The temperature detected by the temperature sensor or infrared thermometer set at the discharge pipe 3 is rapidly cooled to below 200°C, so that the metal particles cannot continue to nucleate into large particles or agglomerate into large powder clumps, thus producing metal powder with a diameter of less than 200nm.

[0048] In Example 4, based on Example 1, the ratio of the inner diameter K of the water-cooled layer of the gas cooling pipe 21 to the outer diameter H of the gas flow layer 211 is 1:2.5. Three gas nozzles 213 are opened circumferentially at the same cross-section position on the outer pipe 8 of the gas flow layer 211, for a total of 80 gas nozzles 213. The inner pipe 11, insulation layer 12, and water-cooled layer 13 of the nucleating pipe 1 are coaxial pipes. At the same cross-section, the ratio of the outer diameter A of the inner pipe 11 to the outer diameter B of the insulation layer 12 is 1:1.05, and the ratio of the outer diameter A of the inner pipe 11 to the outer diameter C of the water-cooled layer is 1:2. The ratio of the inner diameter of the inlet 4 to the inner diameter of the outlet 5 at both ends of the nucleating pipe 1 is 1:1.4. The ratio of the length D of nucleating tube 1 to the length E of the powder-forming chamber 22 of the quench condenser 2 is 1:15; the ratio of the average diameter of nucleating tube 1 to its length D is 1:4; and the ratio of the minimum inner diameter Amin of nucleating tube 1 to the maximum inner diameter G of the powder-forming chamber 22 of the quench condenser 2 is 1:10. Circulating cooling water cooled by an external heat exchanger is introduced into the pipes of water-cooled layer 13, water-cooled layer 23, water-cooled layer 31, and water-cooled layer 4 212. The cooling water temperature in water-cooled layer 23 is controlled below 50℃, and the cooling water temperature in water-cooled layer 4 212 is controlled between 40-50℃. An inert gaseous cooling medium is introduced into the gaseous cooling medium pipe 21, with the input temperature controlled at 40℃ and the flow rate controlled at 70. / h, turn on the external blower, and the metal vapor enters the device from the feed pipe of the inner pipe 11 of the nucleation tube 1 under the action of airflow. After being cooled and nucleated by the nucleation tube 1, it enters the powder forming chamber 22 and is fully mixed with the inert gaseous cooling medium sprayed from the gas nozzle 213. The temperature detected by the temperature sensor or infrared thermometer set at the discharge pipe 3 is rapidly cooled to below 200°C, so that the metal particles cannot continue to nucleate into large particles or agglomerate into large powder clumps, thus producing metal powder with a diameter of less than 400nm.

[0049] In summary, this solution can control the particle size of the powder by changing the temperature and cooling rate inside the powder forming chamber. Specifically, the temperature inside the powder forming chamber can be controlled by introducing cooling water at different temperatures into the second water-cooling layer, introducing gaseous cooling media at different temperatures into the gas cooling pipe, or introducing gaseous cooling media at different flow rates into the gas cooling pipe. Alternatively, the temperature or cooling rate inside the powder forming chamber can be controlled by changing the component size ratio. Through these multiple temperature control methods, the range of temperature control and the cooling rate are wider and faster than traditional methods. This can effectively enable metal vapor to rapidly nucleate and grow into ultrafine metal powder with a certain particle size range, effectively reducing the generation of large particles and particle agglomeration, and reducing product loss inside the equipment. It is suitable for batch continuous production.

[0050] The above are merely preferred embodiments of the present invention.

Claims

1. A device for rapid cooling and nucleation of metal vapor into powder, characterized in that, The system includes a nucleating tube (1), with an inlet (4) and an outlet (5) at its two ends. The nucleating tube (1) includes an inner pipe (11) and a water-cooled layer (13) on the outer wall of the inner pipe (11). The outlet of the nucleating tube (1) is connected to a quench condenser (2). The quench condenser (2) includes a powder forming chamber (22), a gas cooling pipe (21) inside the powder forming chamber (22), and a water-cooled layer (23) on the outer wall of the powder forming chamber (22). The nucleating tube (1) is connected to the inside of the powder forming chamber (22). The powder forming chamber (22) is connected to an outlet pipe (3). The outlet pipe (3) includes an inner pipe (22) and an outlet pipe (5). The water-cooled layer 3 (31) on the outer wall of the inner pipe 2 (32) has an air inlet (6) on the gas cooling pipe (21), and the air inlet (6) extends to the outside of the powder forming chamber (22). Gas nozzles (213) are evenly distributed on the gas cooling pipe (21). The powder forming chamber (22) is shaped like a bullet casing. The end closest to the nucleation pipe (1) is a cylindrical structure, and the end closest to the discharge pipe (3) is an arc-shaped funnel structure. The gas cooling pipes (21) are evenly and parallelly arranged inside the powder forming chamber (22) along the material flow direction. The parallel gas cooling pipes (21) inside the powder forming chamber (22) are connected in sequence through arc-shaped pipes. The tube (21) has a double-layer tube structure, including an inner tube and an outer tube (8). The inner tube contains a water-cooled layer (212) and a gas flow layer between the outer tube (8) and the inner tube. The gas nozzle (213) is located on the surface of the outer tube (8). The inner tube (11) of the nucleating tube (1) is a funnel-shaped tube with a large inlet (4) and a small outlet (5). The inner tube (11), insulation layer (12), and water-cooled layer (13) of the nucleating tube (1) are coaxial tubes. The ratio of the outer diameter A of the inner tube (11) to the outer diameter B of the insulation layer (12) on the same cross section is 1:1~4. The ratio of the outer diameter A of the inner tube (11) to the outer diameter B of the water-cooled layer (13) on the same cross section is 1:1~4. The ratio of C is 1:1~15, the ratio of the inner diameter of the inlet (4) at both ends of the nucleating tube (1) to the inner diameter of the outlet (5) is 1:1~2, the ratio of the length D of the nucleating tube (1) to the length E of the powder forming chamber (22) of the quench condenser (2) is 1:0.5~50, the ratio of the average diameter of the nucleating tube (1) to the length D of the nucleating tube (1) is 1:1~50, the ratio of the minimum inner diameter Amin of the nucleating tube (1) to the maximum inner diameter G of the powder forming chamber (22) of the quench condenser (2) is 1:1~30; the arc of the gas nozzle (213) on the outer tube (8) corresponds to the outer circle center angle of the gas flow layer (211) of 15°~ 45°, the ratio of the inner diameter K of the water cooling layer of the gas cooling pipe (21) to the outer diameter H of the gas flow layer is 1:1~4, and the outer pipe (8) of the gas flow layer (211) has 2-4 gas nozzles (213) in the circumferential direction at the same cross-section position, and the total number of gas nozzles (213) is 30~200.

2. The metal vapor quenching nucleation powder forming apparatus according to claim 1, characterized in that, The outer wall of the water-cooled layer (13) is provided with a heat insulation layer (12), which is a ceramic felt heat insulation layer (12) or a carbon felt heat insulation layer (12).

3. The metal vapor quenching nucleation powder forming apparatus according to claim 2, characterized in that, The number of parallel gas cooling pipes (21) inside the powder forming chamber (22) is greater than 3.

4. The metal vapor quenching nucleation powder forming apparatus according to claim 3, characterized in that, The connection between the nucleation tube (1) and the powder-forming chamber (22) is flared.

5. A method for controlling the particle size of powder formed by rapid cooling and nucleation of metal vapor, characterized in that, Metal vapor is introduced into the feed inlet (4) of the nucleation tube (1) in the metal vapor quenching nucleation powder forming device as described in claim 4. The particle size of the powder is controlled by changing the temperature and cooling rate inside the powder forming chamber (22). Specifically, there are two ways to change the temperature and cooling rate inside the powder forming chamber (22). The first is to introduce cooling water of different temperatures into the water cooling layer (23), gaseous cooling medium of different temperatures into the gas cooling pipe (21), and gaseous cooling medium of different flow rates into the gas cooling pipe (21). The temperature inside the powder forming chamber (22) is controlled by the quality; the second method is to adjust the ratio of the outer diameter A of the inner pipe (11) to the outer diameter B of the insulation layer (12), the ratio of the outer diameter A of the inner pipe (11) to the outer diameter C of the water cooling layer (13), the ratio of the inner diameter of the inlet (4) and the inner diameter of the outlet (5) at both ends of the nucleating tube (1), the ratio of the length D of the nucleating tube (1) to the length E of the powder forming chamber (22) of the quench condenser (2), the ratio of the average diameter of the nucleating tube (1) to the length D of the nucleating tube (1), and the minimum inner diameter A of the nucleating tube (1). min The ratio of the maximum inner diameter G of the powder forming chamber (22) of the condenser (2), the number of gas nozzles (213), the angle of the outer circle center of the gas flow layer corresponding to the arc of the gas nozzle (213) on the outer tube (8), and the ratio of the inner diameter K of the water cooling layer of the gas cooling pipe (21) to the outer diameter H of the gas flow layer.

6. The method for controlling the particle size of metal vapor nucleation powder by rapid cooling according to claim 5, characterized in that, The gaseous cooling medium is nitrogen.

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