Plasma-based ultrafine powder production system and method

Abstract

The application relates to the technical field of superfine powder preparation, in particular to a dual-function plasma superfine powder preparation system and a preparation method, wherein the superfine powder preparation method comprises the following steps: at the moment of arc starting, an arc transfer switch is used to transfer a plasma generator from a cathode to a small anode, and then to a large anode; at this moment, the plasma generator is in a non-transfer arc state, input powder enters a conductive crucible to form a molten body through the plasma generator; after the molten body in the conductive crucible reaches a preset value, the arc transfer switch is used to transfer the plasma generator from the large anode to the small anode, and then to the cathode; at this moment, the plasma generator is in the non-transfer arc state, so that the molten body in the conductive crucible is vaporized; and steam generated by the vaporized molten body enters a second cavity to be condensed into superfine powder which is discharged through a powder outlet. The superfine powder preparation system can be applied to non-conductive inorganic matters.

Description

Technical Field

[0001] This invention relates to the field of ultrafine powder preparation technology, and more specifically, to a plasma-based ultrafine powder preparation system and method. Background Technology

[0002] Currently, in the field of materials preparation, electric arc plasma is often used to prepare ultra-high purity ultrafine powders. Electric arc plasma has high electrothermal conversion efficiency, which can achieve low-cost mass production.

[0003] In existing technologies, plasma devices used for preparing ultrafine powders employ two types of plasma equipment: transferred arc plasma generators and non-transferred arc plasma generators. Transferred arc plasma generators are characterized by high temperatures (5000℃~10000℃), but they are inconvenient to use, requiring a separate external anode to emit the plasma flame. Their environmental practicality is poor, and they can only successfully heat conductive materials, especially inorganic materials in a non-molten state. Non-transferred arc plasma generators, on the other hand, are characterized by low temperatures (approximately 2000℃), are easy to use, and can emit a plasma flame without a separate external anode, offering higher environmental practicality and convenient material heating.

[0004] However, in existing ultrafine powder preparation systems, most materials are non-conductive inorganic substances, which typically require temperatures as high as 3000°C for effective vaporization. If a non-transfer arc plasma generator is used, the temperature requirement cannot be met, resulting in poor powder preparation. If a transfer arc plasma generator is used, it cannot effectively heat the non-conductive inorganic substances. Therefore, neither existing transfer arc plasma generators nor non-transfer arc plasma generators are suitable for the vaporization of these inorganic substances.

[0005] To address the aforementioned issues, we propose a plasma-based ultrafine powder preparation system and method. Summary of the Invention

[0006] The purpose of this invention is to provide a plasma-based ultrafine powder preparation system and method to solve the problem that existing ultrafine powder preparation systems in the background art cannot be applied to non-conductive inorganic materials.

[0007] The first aspect of the present invention provides a plasma-based ultrafine powder preparation system, including a furnace cavity. The outer wall of the furnace cavity is provided with a high-temperature resistant insulation layer and a double-layer stainless steel shell from the inside to the outside. The furnace cavity includes:

[0008] The first chamber has its input end connected to the plasma generator, and a conductive crucible for preparing the melt is installed inside the first chamber.

[0009] The second chamber is configured to communicate with the side of the first chamber away from the plasma generator. The side wall of the second chamber is provided with a condensation inlet and the output end is provided with a powder outlet.

[0010] The ultrafine powder preparation system also includes:

[0011] Plasma power supply, used to power the plasma generator;

[0012] A switching switch is configured to be electrically connected to a plasma power supply. By changing the polarity of the plasma generator electrodes through the plasma power supply, the two working states of the plasma generator, namely the transfer arc and the non-transfer arc, are switched.

[0013] The control unit is configured to control the operating state of the switch.

[0014] The lifting mechanism is used to adjust the distance between the plasma generator and the conductive crucible.

[0015] Furthermore, the plasma generator includes:

[0016] The cathode is electrically connected to the plasma power supply via a cathode terminal;

[0017] The large anode is electrically connected to the plasma power supply via a large anode terminal.

[0018] A small anode is disposed between the cathode and the large anode, and the small anode is electrically connected to the plasma power supply through a small anode terminal;

[0019] Insulating gas rings include an anode gas ring installed between the small anode and the large anode, and a cathode gas ring installed between the small anode and the cathode;

[0020] The water cooling system includes an inlet and an outlet located at one end of the plasma generator. The output end of the inlet is provided with a water cooling channel that passes through a large anode, a small anode, and a cathode in sequence. The output end of the water cooling channel is connected to the outlet.

[0021] The air intake system includes a main air duct and a powder delivery channel. The main air duct and the powder delivery channel work independently and do not interfere with each other.

[0022] The cathode powder inlet pipe has its input end connected to the output end of the powder feeding channel.

[0023] Further, the anode gas ring includes an inner anode gas ring, and an outer anode gas ring is sleeved outside the inner anode gas ring by a positioning component. The inner anode gas ring includes:

[0024] Several first water passage holes are evenly arranged on the outer ring of the inner ring of the anode gas ring;

[0025] Several first oblique vents are evenly arranged on the inner ring of the inner ring of the anode gas ring;

[0026] The air inlets are distributed around the outer perimeter of the inner ring of the anode and extend inward to the inner ring of the inner ring of the anode.

[0027] The outer ring of the anode gas ring is provided with several first bolt through holes, and the anode gas ring is installed between the large anode and the small anode of the plasma generator through the first bolt through holes.

[0028] Furthermore, the cathode gas ring includes a threaded inner cathode ring and an outer cathode ring, and further includes:

[0029] Several second water passages are evenly arranged on the outer side of the circumference of the inner ring of the cathode;

[0030] Several second oblique vents are evenly arranged on one side of the inner ring of the cathode;

[0031] Several semi-circular positioning grooves are evenly distributed on the outer side of the outer ring circumference of the cathode;

[0032] Several second bolt through holes are evenly arranged on the outer surface of the cathode outer ring. The cathode gas ring is installed between the cathode and the small anode of the plasma generator through the second bolt through holes.

[0033] Furthermore, it also includes an observation mechanism, which comprises:

[0034] An observation window is located on one side of the first cavity, and a high-temperature resistant glass matching the observation window is embedded on the side of the observation window away from the first cavity;

[0035] A protective mechanism, installed on the observation window, is used to cool and protect the high-temperature resistant glass.

[0036] Furthermore, the protection mechanism includes:

[0037] An airflow protection channel is located on the side of the high-temperature resistant glass near the observation window and passes through the observation window;

[0038] The water inlet of the observation window is located on the side of the observation window closest to the second cavity.

[0039] The water outlet of the observation window is symmetrically arranged with the water inlet of the observation window.

[0040] Furthermore, the double-layer stainless steel housing includes:

[0041] The interlayer water inlet is located on one side of the second cavity;

[0042] The interlayer water outlet is located on one side of the first cavity and is positioned opposite the interlayer water inlet.

[0043] Furthermore, a sealing device is provided between the plasma generator and the first cavity, the sealing device being sealed to the first cavity and slidably connected to the plasma generator.

[0044] Furthermore, the plasma power supply is also connected to a conductive electrode via a switching switch, and a first insulating sleeve is provided between the conductive electrode and the first cavity.

[0045] The second aspect of the present invention provides a plasma-based method for preparing ultrafine powders, applied to any one of the plasma-based ultrafine powder preparation systems described in the first aspect of the present invention, comprising:

[0046] At the moment the plasma generator ignites the arc, the switching switch transfers the plasma generator from the cathode to the small anode, and then to the large anode. At this time, the plasma generator is in a non-transfer arc state. The input powder enters the conductive crucible through the plasma generator to form a melt.

[0047] Once the molten material in the conductive crucible reaches the preset value, the plasma generator is transferred from the large anode to the small anode and then to the cathode by switching the switch. At this time, the plasma generator is in a non-transfer arc state so that the molten material in the conductive crucible is vaporized.

[0048] The steam generated by the vaporization of the melt enters the second chamber, condenses into ultrafine powder, and is then discharged through the powder outlet.

[0049] The beneficial effects of this invention include:

[0050] 1. This invention achieves switching between two working states of the plasma generator—transfer arc and non-transfer arc—by setting up a plasma power supply and a switching switch, and by changing the polarity of the plasma generator electrodes through the plasma power supply. When applied to non-conductive inorganic materials, the non-conductive inorganic material is first melted by the high-temperature plasma flame ejected from the non-transfer arc state of the plasma generator. The molten non-conductive inorganic material then becomes conductive. Once the melt in the conductive crucible reaches a preset temperature, the temperature of the high-temperature plasma flame ejected from the non-transfer arc state of the plasma generator is raised to over 3000°C, causing the melt in the conductive crucible to vaporize. The vapor generated by the vaporization enters the second chamber, condenses into ultrafine powder, and is discharged through the powder outlet, ultimately achieving the preparation of ultrafine powder from the non-conductive inorganic material. Attached Figure Description

[0051] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments of the present invention will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0052] Figure 1 This is a schematic diagram of the overall structure of the ultrafine powder preparation system provided in an embodiment of the present invention;

[0053] Figure 2 This is a schematic diagram of the structure of a plasma generator provided in an embodiment of the present invention;

[0054] Figure 3 for Figure 2 A magnified view of part B in the middle section;

[0055] Figure 4 This is a schematic diagram of the structure of the anode gas ring provided in an embodiment of the present invention;

[0056] Figure 5 This is a front view of the anode gas ring provided in an embodiment of the present invention;

[0057] Figure 6 for Figure 5 Sectional view of AA;

[0058] Figure 7 This is a schematic diagram of the outer ring structure of the anode gas ring provided in an embodiment of the present invention;

[0059] Figure 8 This is a front view of the anode gas ring provided in an embodiment of the present invention;

[0060] Figure 9 for Figure 8 Sectional view of FF;

[0061] Figure 10 This is a schematic diagram of the inner ring structure of the anode gas ring provided in an embodiment of the present invention;

[0062] Figure 11 This is a front view of the inner ring of the anode gas ring provided in an embodiment of the present invention;

[0063] Figure 12 for Figure 11 Sectional view of FF;

[0064] Figure 13 This is a schematic diagram of the cathode gas ring provided in an embodiment of the present invention;

[0065] Figure 14 This is a front view of the cathode gas ring provided in an embodiment of the present invention;

[0066] Figure 15 for Figure 14 Sectional view of AA;

[0067] Figure 16 for Figure 1 A magnified view of part A in the middle;

[0068] Figure 17 This is a flowchart of the ultrafine powder preparation method provided in the embodiments of the present invention;

[0069] Icons: 100-Furnace cavity, 110-First cavity, 111-Fixed flange, 112-Flange inlet, 113-Flange outlet, 120-Second cavity, 121-Condensate inlet, 122-Powder outlet, 130-High-temperature insulation layer, 140-Double-layer stainless steel shell, 141-Jack-layer inlet, 142-Jack-layer outlet, 200-Plasma generator, 210-Cathode, 211-Cathode wiring End, 220-Large anode, 221-Large anode terminal, 230-Small anode, 231-Small anode terminal, 240-Anode gas ring, 241-Inner ring of anode gas ring, 2411-Outer ring, 2412-Inner ring, 2413-Mounting platform, 2414-First positioning boss, 242-Outer ring of anode gas ring, 243-First water passage hole, 244-First oblique air hole, 245-Air inlet, 246-First bolt 247 - Through hole; 248 - Mounting concave surface; 249 - Second positioning boss; 250 - Second insulating sleeve; 251 - Cathode gas ring; 252 - Cathode inner ring; 253 - Cathode outer ring; 254 - Second water passage hole; 255 - Second oblique air hole; 256 - Semi-circular positioning groove; 260 - Second bolt through hole; 261 - Water inlet; 262 - Water outlet; 270 - Main air passage; 271 - Powder delivery passage. 272-Cathode powder inlet pipe, 273-Main air inlet, 274-Mounting hole, 300-Conductive crucible, 400-Plasma power supply, 410-Switch, 420-Conductive electrode, 430-First insulating sleeve, 500-Lifting mechanism, 600-Observation window, 610-High temperature resistant glass, 620-Airflow protection channel, 630-Observation window inlet, 640-Observation window outlet, 700-Sealing device. Detailed Implementation

[0070] The technical solutions of the present invention will now be described with reference to the accompanying drawings in the embodiments of the present invention.

[0071] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0072] Please refer to Figure 1 As shown, the first aspect of the present invention provides a plasma-based ultrafine powder preparation system, including a furnace cavity 100. The outer wall of the furnace cavity 100 is provided with a high-temperature resistant insulation layer 130 and a double-layer stainless steel shell 140 from the inside to the outside. The furnace cavity 100 includes:

[0073] The first cavity 110 has its input end connected to the plasma generator 200. A conductive crucible 300 for preparing the melt is installed inside the first cavity 110. The first cavity 110 is connected to the plasma generator 200 through a fixed flange 111. The fixed flange 111 has a flange inlet 112 and a flange outlet 113 on both sides. The purpose of setting the flange inlet 112 and the flange outlet 113 is to keep the outer surface of the fixed flange 111 at room temperature.

[0074] The second chamber 120 is configured to communicate with the side of the first chamber 110 away from the plasma generator 200. A condensation inlet 121 is provided on the side wall of the second chamber 120, and a powder outlet 122 is provided at the output end. The condensation inlet 121 is used to supply a low-temperature inert gas with a temperature between -100℃ and 30℃, the purpose of which is to accelerate the condensation of steam within the second chamber 120, allowing the steam to quickly condense into ultrafine powder. A powder baffle, detachably connected to the second chamber 120, can also be provided on the outside of the powder outlet 122, and the powder baffle is bolted to the second chamber 120.

[0075] The ultrafine powder preparation system also includes:

[0076] Plasma power supply 400 is used to power plasma generator 200;

[0077] The switch 410 is configured to be electrically connected to the plasma power supply 400. The polarity of the electrodes of the plasma generator 200 is changed by the plasma power supply 400, thereby switching between the two working states of the plasma generator 200: transfer arc and non-transfer arc.

[0078] The control unit is configured to control the working state of the switch 410; wherein, the control unit can be configured as an existing controller with control capabilities, such as a microcontroller or a microcomputer, as long as it can control the switch 410, and is not limited thereto.

[0079] A lifting mechanism 500 is used to adjust the distance between the plasma generator 200 and the conductive crucible 300. The lifting mechanism 500 can be a device with object lifting function, such as an electric telescopic rod, a worm gear screw jack, or a hydraulic lifting mechanism 500, which are existing technologies. The control unit can also be configured to control the lifting mechanism 500, thereby realizing the vertical displacement of the plasma generator 200. The purpose is to adjust the distance between the plasma generator 200 and the conductive crucible 300 through the lifting mechanism 500, thereby adjusting the power of plasma generation so that the power of the plasma generator 200 matches the working state of the transfer arc or non-transfer arc.

[0080] Preferably, one end of the lifting mechanism 500 is fixedly connected to the first cavity 110, and the plasma generator 200 is provided with a mounting hole 274 on the side near the lifting mechanism 500. The mounting hole 274 is used to fix the plasma generator 200 on the lifting mechanism 500.

[0081] The plasma-based ultrafine powder preparation system provided in this embodiment achieves switching between two working states of the plasma generator 200—transfer arc and non-transfer arc—by setting up a plasma power supply 400 and a switching switch 410, and changing the polarity of the electrodes of the plasma generator 200 through the plasma power supply 400. When applied to non-conductive inorganic materials, the high-temperature plasma flame ejected from the non-transfer arc state of the plasma generator 200 first melts the non-conductive inorganic material, which then becomes conductive. After the melt in the conductive crucible 300 reaches a preset value, the plasma generator 200 is then switched back to the non-transfer arc state. In this state, the temperature of the high-temperature plasma flame ejected from the plasma generator 200 is raised to over 3000°C, causing the melt in the conductive crucible 300 to vaporize. The vapor generated by the vaporization of the melt enters the second chamber 120, condenses into ultrafine powder, and is discharged through the powder outlet 122, ultimately realizing the preparation of ultrafine powder from non-conductive inorganic materials.

[0082] For example, such as Figure 2 and Figure 3 As shown, the plasma generator 200 includes:

[0083] Cathode 210, which is electrically connected to plasma power supply 400 via cathode terminal 211;

[0084] Large anode 220, which is electrically connected to plasma power supply 400 via large anode terminal 221;

[0085] Small anode 230 is disposed between cathode 210 and large anode 220, and small anode 230 is electrically connected to plasma power supply 400 through small anode terminal 231;

[0086] In their practical work, the inventors discovered that plasma generators with multiple small anodes in the prior art cannot be used for the conversion between transfer arc and non-transfer arc states. The plasma generator 200 provided in this embodiment has only one cathode 210, one large anode 220 and one small anode 230. By reducing the number of small anodes 230, the plasma generator 200 can be used for the conversion between transfer arc and non-transfer arc states.

[0087] The insulating gas ring includes an anode gas ring 240 installed between the small anode 230 and the large anode 220, and a cathode gas ring 250 installed between the small anode 230 and the cathode 210. The insulating gas ring is preferably made of a high-molecular insulating material. It is an essential component for the stable gas supply to the plasma generator 200, ensuring smooth plasma flame ejection and completely separating the gas path and water path of the plasma generator 200 so that they do not interfere with each other. The working gas of the plasma generator 200 can be one of air, nitrogen, or argon.

[0088] The water cooling system includes an inlet 260 and an outlet 261 located at one end of the plasma generator 200. The output end of the inlet 260 is provided with a water cooling channel 262 that sequentially passes through a large anode 220, a small anode 230, and a cathode 210. The output end of the water cooling channel 262 is connected to the outlet 261. In this embodiment, the plasma generator 200 is provided with only one inlet 260 and one outlet 261 to facilitate installation and connection with other equipment.

[0089] The air intake system includes a main air duct 270 and a powder delivery channel 271. The main air duct 270 and the powder delivery channel 271 work independently and do not interfere with each other.

[0090] The cathode powder inlet pipe 272 has its input end connected to the output end of the powder feeding channel 271;

[0091] The plasma generator 200 provided in this embodiment preferably has a stainless steel shell. In actual use, the length of the plasma generator 200 can be adjusted according to actual working needs. When applied to non-conductive inorganic materials, its working principle is as follows: at the moment the plasma generator 200 starts arcing, it transfers from the cathode 210 to the small anode 230, and then to the large anode 220. At this time, the plasma generator 200 is in a non-transfer arc state. At this time, the powder is sent into the generator cathode powder inlet pipe 272 through the powder feeding channel 271, and then passes through the arc zone of the plasma generator 200 and forms a molten liquid that enters the conductive crucible 300. When there is enough molten material in the conductive crucible 300, the control unit controls the switching switch 410 to switch the working state of the plasma generator 200 from the non-transfer state to the transfer arc state, thereby realizing the vaporization of the molten material.

[0092] With the expansion of the application of plasma generator 200, unlike the above embodiments, the plasma generator 200 in this embodiment can select water vapor as the working gas of plasma generator 200. According to the characteristics of steam, the anode gas ring 240 and cathode gas ring 250 in this embodiment are preferably made of insulating and high temperature resistant materials so that the anode gas ring 240 and cathode gas ring 250 do not deform under high temperature and high pressure working environment.

[0093] For example, such as Figures 4 to 12 As shown, the anode gas ring 240 is installed between the small anode 230 and the large anode 220 of the plasma generator 200. The anode gas ring 240 is made of insulating and high-temperature resistant material and includes an inner anode gas ring 241. An outer anode gas ring 242 is sleeved on the outside of the inner anode gas ring 241 through a positioning component. The inner anode gas ring 241 includes:

[0094] Several first water passage holes 243 are evenly arranged on the outer ring 2411 of the inner ring 241 of the anode gas ring; the first water passage holes 243 are used to pass in the cooling medium liquid; by setting multiple first water passage holes 243, the water flow rate of the anode gas ring 240 is increased, thereby improving the heat dissipation effect of the anode gas ring 240.

[0095] Several first oblique air holes 244 are evenly arranged on the inner ring 2412 of the inner ring 241 of the anode gas ring; the first oblique air holes 244 are used to introduce working gas into the anode of the plasma generator 200, and the first oblique air holes 244 can make the working gas form a rotating airflow, which eventually enters the anode arc channel of the plasma generator 200.

[0096] The air inlet 245 is distributed around the outer ring 2411 of the inner ring 241 of the anode gas ring and extends inward to the inner ring 2412 of the inner ring 241 of the anode gas ring.

[0097] The first water passage 243 and the second oblique air passage 254 work independently and do not interfere with each other; the outer ring 242 of the anode air ring is provided with a plurality of first bolt through holes 246, and the anode air ring 240 is installed between the large anode 220 and the small anode 230 of the plasma generator 200 through the first bolt through holes 246.

[0098] The following is a preferred embodiment of the anode gas ring 240:

[0099] The system includes 28 first water passage holes 243, which are evenly distributed on the outer ring 2411 of the inner ring 241 of the anode gas ring. The number of first water passage holes 243 can be adjusted according to actual needs. There are also 16 first oblique air holes 244, which are evenly distributed on the inner ring 2412 of the inner ring 241 of the anode gas ring. The number of first oblique air holes 244 can also be adjusted according to actual needs. Furthermore, there are 8 first bolt through holes 246, which can also be adjusted according to actual needs. By using bolt installation, water and air leakage problems caused by radial installation of the anode gas ring 240 can be effectively avoided.

[0100] The anode gas ring 240 provided in this embodiment, based on the characteristics of water vapor working gas, is provided with an outer anode gas ring 242 and an inner anode gas ring 241 to facilitate the processing of the anode gas ring 240. By providing a first water passage 243, a first oblique gas hole 244, and an air inlet 245, the water path and gas path of the plasma generator 200 anode can work independently, playing a protective role in supplying gas to the anode. During the gas supply process, the air inlet 245 can play a role in uniformly distributing the airflow, and then the first oblique gas hole 244 can form a rotating airflow, thereby improving the stability of the airflow when supplying gas to the anode of the plasma generator 200. On the other hand, the anode gas ring 240 is made of insulating and high-temperature resistant material, so that it will not deform under the high temperature and high pressure environment of water vapor.

[0101] Among them, such as Figure 9 and Figure 12 As shown, the positioning component includes:

[0102] Mounting platform 2413 is located on one side of the inner ring 241 of the anode gas ring;

[0103] The mounting concave surface 247 is provided on the outer ring 242 of the anode gas ring and is sealed to the mounting platform 2413;

[0104] By setting the mounting platform 2413 and the mounting recess 247, the gas leakage inside the anode gas ring 240 is prevented.

[0105] The first positioning boss 2414 is located on the side of the inner ring 241 of the anode gas ring away from the mounting platform 2413, and is used for positioning and installation with the outer ring 242 of the anode gas ring.

[0106] The second positioning boss 248 is located on the outside of the mounting recess 247 and is used for positioning and mounting with the plasma generator 200.

[0107] Preferred, such as Figure 9 As shown, a second insulating sleeve 249 is fitted on the outer ring 242 of the anode gas ring. In this embodiment, the second insulating sleeve 249 is used to protect the anode gas ring 240 from the outside world. After the anode gas ring 240 is installed on the anode, the anode part is wrapped by the second insulating sleeve 249 to prevent contact with the outside world. The second insulating sleeve 249 can be made of rubber material, and its size is based on being able to wrap the anode of the plasma generator 200. It is not limited here.

[0108] For example, such as Figures 13 to 15 As shown, the cathode gas ring 250 includes a threaded inner cathode ring 251 and an outer cathode ring 252, and further includes:

[0109] Several second water passage holes 253 are evenly arranged on the outer side of the circumference of the inner ring 251 of the cathode; the second water passage holes 253 are used to pass in the cooling medium liquid; by setting multiple second water passage holes 253, the water flow rate of the cathode air ring 250 is increased, thereby improving the heat dissipation effect of the cathode air ring 250.

[0110] Several second oblique vents 254 are evenly arranged on one side of the inner ring 251 of the cathode; the second oblique vents 254 are used to introduce working gas into the cathode 210 of the plasma generator 200, and the second oblique vents 254 can make the working gas form a rotating airflow, which eventually enters the cathode arc channel of the plasma generator 200.

[0111] Several semi-circular positioning grooves 255 are evenly distributed on the outer side of the circumference of the cathode outer ring 252;

[0112] Several second bolt through holes 256 are evenly arranged on the outer surface of the cathode outer ring 252. The cathode gas ring 250 is installed between the cathode 210 and the small anode 230 of the plasma generator 200 through the second bolt through holes 256.

[0113] The cathode outer ring 252 is provided with a plurality of second bolt through holes 256, and the cathode outer ring 252 is installed between the cathode 210 and the small anode 230 of the plasma generator 200 through the second bolt through holes 256.

[0114] The second water passage 253 and the second oblique air passage 254 work independently and do not interfere with each other;

[0115] The following is a preferred embodiment of the cathode gas ring 250:

[0116] There are eight second bolt through holes 256, which are evenly distributed on the outer cathode ring 252. The second bolt through holes 256 can be adjusted according to actual needs. The cathode gas ring 250 is installed between the cathode 210 and the small anode 230 of the plasma generator 200 through the second bolt through holes 256. The bolt installation method can effectively avoid water and air leakage problems caused by radial installation of the cathode gas ring 250. There are eight second water passage holes 253, which are evenly distributed on the outer side of the circumference of the inner cathode ring 251. The number of second water passage holes 253 can also be adjusted according to actual needs; there are a total of 8 second oblique air holes 254, which are evenly arranged on one side of the inner ring 251 of the cathode, and the number of second oblique air holes 254 can also be adjusted according to actual needs; there are a total of 8 semi-circular positioning grooves 255, which are evenly arranged on the outer side of the circumference of the outer ring 252 of the cathode, and the number of semi-circular positioning grooves 255 can also be adjusted according to actual needs; the semi-circular positioning grooves 255 serve to facilitate the installation and positioning with external devices;

[0117] The cathode gas ring 250 provided in this embodiment, based on the characteristics of water vapor working gas, is provided with an inner cathode ring 251 and an outer cathode ring 252 to facilitate the processing of the cathode gas ring 250. By providing a second water passage 253 and a second oblique air passage 254, the water passage and air passage of the plasma generator 200 cathode 210 can work independently, which plays a protective role in the gas supply of the cathode 210. During the gas supply process, the second oblique air passage 254 can form a rotating airflow, thereby improving the airflow stability when the plasma generator 200 cathode 210 is supplied with gas. On the other hand, the cathode gas ring 250 is made of insulating and high-temperature resistant material, so that it will not deform under the high temperature and high pressure environment of water vapor.

[0118] For example, such as Figure 1 and Figure 16 As shown, it also includes an observation mechanism, which includes:

[0119] An observation window 600 is provided on one side of the first cavity 110, and a high-temperature resistant glass 610 matching the observation window is embedded on the side of the observation window 600 away from the first cavity 110. In this embodiment, the observation window 600 is provided to facilitate the observation of the material reaction in the first cavity 110. For example, the observation window 600 can be used to observe whether the melt in the conductive crucible 300 has reached a preset value.

[0120] A protective mechanism, installed on the observation window 600, is used to cool and protect the high-temperature resistant glass 610. The protective mechanism includes:

[0121] An airflow protection channel 620 is located on the side of the high-temperature resistant glass 610 near the observation window 600 and passes through the observation window 600. In practical applications, room temperature inert gas is introduced through the airflow protection channel 620 to cool and protect the high-temperature resistant glass 610, and at the same time, it can also prevent powder from adsorbing on the outer surface of the high-temperature resistant glass 610 and affecting the observation effect.

[0122] The observation window 600 inlet 260 is located on the side of the observation window 600 near the second cavity 120; the observation window outlet 261 is symmetrically arranged with the observation window 600 inlet 260; by setting the observation window inlet 260 and the observation window outlet 261, the observation window 600 is cooled and protected.

[0123] For example, such as Figure 1 As shown, the double-layer stainless steel housing 140 includes:

[0124] The interlayer water inlet 260141 is located on one side of the second cavity 120;

[0125] The interlayer water outlet 142 is located on one side of the first cavity 110 and is opposite to the interlayer water inlet 141. In this embodiment, by setting the interlayer water inlet 141 and the interlayer water outlet 142, cooling water is introduced into the double-layer stainless steel shell 140 during actual use so that the double-layer stainless steel shell 140 is kept at room temperature during operation, thereby extending the service life of the device.

[0126] For example, similarly Figure 1 As shown, a sealing device 700 is also provided between the plasma generator 200 and the first cavity 110. The sealing device 700 is sealed to the first cavity 110 and slidably connected to the plasma generator 200. In this embodiment, by setting the sealing device 700, the first cavity 110 can be kept sealed when the plasma generator 200 rises or falls under the drive of the lifting mechanism 500, preventing external air from entering the first cavity 110. The sealing device 700 is preferably made of an insulating and high-temperature resistant material.

[0127] For example, similarly Figure 1 As shown, the plasma power supply 400 is also connected to a conductive electrode 420 via a switching switch 410, and a first insulating sleeve 430 is provided between the conductive electrode 420 and the first cavity 110. In this embodiment, by providing the first insulating sleeve 430, a short circuit between the plasma power supply 400 and the furnace cavity 100 is prevented, thereby ensuring the stable operation of the ultrafine powder preparation system.

[0128] Please see Figure 17 As shown, the second aspect of the present invention provides a plasma-based method for preparing ultrafine powders, applied to any one of the plasma-based ultrafine powder preparation systems described in the first aspect of the present invention, comprising:

[0129] Step S1: At the moment the plasma generator 200 starts to ignite, the switching switch 410 transfers the plasma generator 200 from the cathode 210 to the small anode 230, and then to the large anode 220. At this time, the plasma generator 200 is in a non-transfer arc state. The input powder enters the conductive crucible 300 through the plasma generator 200 to form a melt.

[0130] Step S2: After the molten material in the conductive crucible 300 reaches the preset value, the plasma generator 200 is transferred from the large anode 220 to the small anode 230 and then to the cathode 210 via the switching switch 410. At this time, the plasma generator 200 is in a non-transfer arc state to vaporize the molten material in the conductive crucible 300. The preset value of the molten material is based on the actual volume of the conductive crucible 300 and the actual requirements of the molten material in actual operation, and is not limited here.

[0131] Step S3: The steam generated by the vaporization of the melt enters the second chamber 120, condenses into ultrafine powder, and is then discharged through the powder outlet 122.

[0132] In summary, the plasma-based ultrafine powder preparation system and method provided in this application solve the problem that existing ultrafine powder preparation systems cannot be applied to non-conductive inorganic materials. At the same time, the system has been optimized and improved in terms of sealing performance and operational safety, thereby enabling the ultrafine powder preparation system to operate stably in practical applications.

[0133] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A plasma-based ultrafine powder preparation device, characterized in that, The furnace cavity includes a high-temperature resistant insulation layer and a double-layer stainless steel shell arranged sequentially from the inside to the outside on its outer wall. The first chamber has its input end connected to the plasma generator, and a conductive crucible for preparing the melt is installed inside the first chamber. The second chamber is configured to communicate with the side of the first chamber away from the plasma generator. The side wall of the second chamber is provided with a condensation inlet and the output end is provided with a powder outlet. The ultrafine powder preparation device also includes: Plasma power supply, used to power the plasma generator; A switching switch is configured to be electrically connected to a plasma power supply. By changing the polarity of the plasma generator electrodes through the plasma power supply, the two working states of the plasma generator, namely the transfer arc and the non-transfer arc, are switched. The control unit is configured to control the operating state of the switch. A lifting mechanism is used to adjust the distance between the plasma generator and the conductive crucible; The plasma generator includes: The cathode is electrically connected to the plasma power supply via a cathode terminal; The large anode is electrically connected to the plasma power supply via a large anode terminal. A small anode is disposed between the cathode and the large anode, and the small anode is electrically connected to the plasma power supply through a small anode terminal; Insulating gas rings include an anode gas ring installed between the small anode and the large anode, and a cathode gas ring installed between the small anode and the cathode; The water cooling system includes an inlet and an outlet located at one end of the plasma generator. The output end of the inlet is provided with a water cooling channel that passes through a large anode, a small anode, and a cathode in sequence. The output end of the water cooling channel is connected to the outlet. The air intake system includes a main air duct and a powder delivery channel. The main air duct and the powder delivery channel work independently and do not interfere with each other. The cathode powder inlet pipe has its input end connected to the output end of the powder feeding channel; The anode gas ring includes an inner anode gas ring, and an outer anode gas ring is sleeved outside the inner anode gas ring via a positioning component. The inner anode gas ring includes: Several first water passage holes are evenly arranged on the outer ring of the inner ring of the anode gas ring; Several first oblique vents are evenly arranged on the inner ring of the inner ring of the anode gas ring; The air inlets are distributed around the outer perimeter of the inner ring of the anode and extend inward to the inner ring of the inner ring of the anode. The outer ring of the anode gas ring is provided with several first bolt through holes, and the anode gas ring is installed between the large anode and the small anode of the plasma generator through the first bolt through holes; The cathode gas ring includes a threaded inner cathode ring and an outer cathode ring, and further includes: Several second water passages are evenly arranged on the outer side of the circumference of the inner ring of the cathode; Several second oblique vents are evenly arranged on one side of the inner ring of the cathode; Several semi-circular positioning grooves are evenly distributed on the outer side of the outer ring circumference of the cathode; Several second bolt through holes are evenly arranged on the outer surface of the cathode outer ring. The cathode gas ring is installed between the cathode and the small anode of the plasma generator through the second bolt through holes.

2. The plasma-based ultrafine powder preparation apparatus according to claim 1, characterized in that, It also includes an observation mechanism, which includes: An observation window is located on one side of the first cavity, and a high-temperature resistant glass matching the observation window is embedded on the side of the observation window away from the first cavity; A protective mechanism, installed on the observation window, is used to cool and protect the high-temperature resistant glass.

3. The plasma-based ultrafine powder preparation apparatus according to claim 2, characterized in that, The protection mechanism includes: An airflow protection channel is located on the side of the high-temperature resistant glass near the observation window and passes through the observation window; The water inlet of the observation window is located on the side of the observation window closest to the second cavity. The water outlet of the observation window is symmetrically arranged with the water inlet of the observation window.

4. The plasma-based ultrafine powder preparation apparatus according to claim 1, characterized in that, The double-layer stainless steel housing includes: The interlayer water inlet is located on one side of the second cavity; The interlayer water outlet is located on one side of the first cavity and is positioned opposite the interlayer water inlet.

5. The plasma-based ultrafine powder preparation apparatus according to claim 1, characterized in that, A sealing device is also provided between the plasma generator and the first cavity. The sealing device is sealed to the first cavity and slidably connected to the plasma generator.

6. The plasma-based ultrafine powder preparation apparatus according to any one of claims 1 to 5, characterized in that, The plasma power supply is also connected to a conductive electrode via a switching switch, and a first insulating sleeve is provided between the conductive electrode and the first cavity.

7. A plasma-based method for preparing ultrafine powders, applied to the plasma-based ultrafine powder preparation apparatus according to any one of claims 1 to 6, characterized in that, include: At the moment the plasma generator ignites the arc, the switching switch transfers the plasma generator from the cathode to the small anode, and then to the large anode. At this time, the plasma generator is in a non-transfer arc state. The input powder enters the conductive crucible through the plasma generator to form a melt. Once the molten material in the conductive crucible reaches the preset value, the plasma generator is switched from the large anode to the small anode and then to the cathode using a switching switch. At this time, the plasma generator is in the transfer arc state to vaporize the molten material in the conductive crucible. The steam generated by the vaporization of the melt enters the second chamber, condenses into ultrafine powder, and is then discharged through the powder outlet.

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