High-temperature reactor for preparing metal particles by plasma arc

Abstract

The utility model belongs to the field of metal particle manufacturing equipment, and relates to a high-temperature reactor for preparing metal particles by using a plasma arc. The high-temperature reactor comprises a furnace body and a plasma transferred arc gun, a main body crucible and a crucible cover are arranged in the furnace body, the main body crucible and the crucible cover are combined to form a high-temperature evaporation cavity, the plasma transferred arc gun extends into the furnace body and penetrates through the crucible cover to extend into the high-temperature evaporation cavity, and the high-temperature evaporation cavity is communicated with a carrier gas inlet, a metal steam outlet and a channel; the metal vapor outlet and the channel are arranged on the crucible cover and / or the main body crucible, and an auxiliary heating device capable of heating the interior of the high-temperature evaporation cavity is arranged on the periphery of the main body crucible and / or the crucible cover. Due to the fact that the auxiliary heating device is arranged on the periphery of the main body crucible and / or the crucible cover, the interior of the high-temperature evaporation cavity can be heated, even if the diameter of a plasma arc column of the plasma transferred arc gun is not changed, the metal liquid level at the edge is heated and reaches the boiling point temperature, the evaporation sectional area proportion of the metal liquid level is increased, and the preparation capacity of metal particles is improved.

Description

Technical Field

[0001] The present application belongs to the field of metal particle manufacturing equipment, and relates to a high-temperature reactor for preparing metal particles by plasma arc. Background Art

[0002] The existing metal powder evaporator uses a plasma transfer arc generated by a plasma spray gun in a container to heat solid metal into metal vapor, and then collects metal particles generated in the metal vapor to obtain a metal powder product.

[0003] A high-temperature reactor for manufacturing micro-nano-scale metal powders comprises a main body with an opening at the upper end and an upper cover covering the opening at the upper end of the main body and having an upwardly concave middle portion. The main body is made of an inner high-temperature resistant layer, a middle supporting layer, and an outer protective layer. The high-temperature resistant layer is made of an aluminum oxide, magnesium oxide, or zirconium oxide ceramic material or a graphite material of the same quality as the upper cover, the supporting layer is filled with aluminum oxide, magnesium oxide, or zirconium oxide material, the protective layer is made of a graphite material that does not deform at high temperatures, and an air inlet hole is vertically arranged on the outside of the total thickness of the protective layer. The upper cover is provided with an exhaust hole, a centrally arranged plasma spray gun and more than three inner channels or grooves arranged at intervals. The air inlet of each inner channel or groove opens at the lower end surface of the upper cover, and the air outlet opens at the inner surface of the upper cover. The air outlet is lower than the exhaust hole. The lower end surface of the nozzle of the plasma spray gun is flush with the upper end surface of the main body or extends into the main body below the upper end surface of the main body. A lower opening is centrally arranged on the bottom wall of the main body, and the lower side of the lower opening is blocked with a graphite block. Air inlet holes are circumferentially arranged at intervals on the side wall of the main body, which are connected from bottom to top and one by one with the lower air inlet of the inner channel or groove.

[0004] The heating of the high-temperature reactor is related to the plasma arc column generated by the plasma transfer arc gun. The diameter of the plasma arc column in the high-temperature reactor is limited and does not increase with the increase of power. Even if the output power of the high-temperature reactor increases, the diameter of the plasma arc column will not continue to increase after reaching a certain size. The metal liquid surface area covered by the plasma arc column is limited. After the metal liquid surface dissipates heat away from the outer position of the arc column, the metal liquid surface temperature at the edge is low and cannot be effectively evaporated, affecting the metal particle preparation capacity. Utility Model Content

[0005] In order to improve the preparation efficiency of metal particles, the present application provides a high-temperature reactor for preparing metal particles using a plasma arc.

[0006] The present application provides a high temperature reactor for preparing metal particles using a plasma arc, which adopts the following technical solution:

[0007] A high-temperature reactor for preparing metal particles by plasma arc, the high-temperature reactor comprising a furnace body and a plasma transfer arc gun, the furnace body having a main crucible and a crucible cover, the crucible cover being located above the main crucible, the two forming a high-temperature evaporation chamber, the plasma transfer arc gun extending into the furnace body and extending through the crucible cover into the high-temperature evaporation chamber, the plasma transfer arc gun being coated with heat-insulating materials and high-temperature resistant materials, the high-temperature evaporation chamber being connected with a carrier gas inlet, a metal vapor outlet and a channel or a metal nucleation channel or a metal vapor nucleation droplet channel being arranged on the crucible cover and / or the main crucible, and being connected with the high-temperature evaporation chamber, the periphery of the main crucible and / or the crucible cover being provided with an auxiliary heating device capable of heating the metal melt in the high-temperature evaporation chamber, the maximum diameter D of the metal liquid surface of the high-temperature reactor being 1:0.2-0.8 to the inlet inner diameter D1-1 of the metal vapor outlet and the channel or the metal nucleation channel or the metal vapor nucleation droplet channel;

[0008] The stacking height H2 is the sum of the crucible cover height H1 and the transfer arc gun channel height H3 in the furnace body. The ratio of the inlet inner diameter D1-1 of the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel to the stacking height H2 is 1:2-15.

[0009] By adopting the above technical solution, the solid-liquid metal is placed in the high-temperature evaporation chamber, and the plasma transfer arc gun and the solid metal in the main crucible form a loop to melt and evaporate the solid metal in the high-temperature evaporation chamber. Since the main crucible and / or the crucible cover are provided with an auxiliary heating device on the periphery, the high-temperature evaporation chamber can be heated. Even if the diameter of the plasma arc column of the plasma transfer arc gun remains unchanged, the metal liquid surface at the edge can still be effectively heated and reach the boiling point temperature, so that the proportion of the evaporation cross-sectional area of ​​the metal liquid surface in the high-temperature evaporation chamber becomes larger, thereby improving the preparation capacity of metal particles.

[0010] Preferably, the auxiliary heating device includes a resistance heater, which is located outside the main crucible, connected to an auxiliary electrode, connected to a water cooling device, and the resistance heater is a heating graphite used to heat the molten metal in the high-temperature reactor; or the auxiliary heating device includes a high-frequency induction heater or a medium-frequency induction heater, which is used to heat the molten metal in the high-temperature reactor, and the distance between the auxiliary heating device and the outer wall of the main crucible is 1-250mm.

[0011] By adopting the above technical solution, the resistance heater or the induction heater can effectively heat and evaporate the periphery of the liquid metal in the high-temperature reactor at a constant temperature.

[0012] Preferably, the gas heated by the plasma transfer arc gun includes inert gas and / or hydrogen, the working voltage of the plasma transfer arc gun is 100-220V, the working current is 350-1200A; the pressure in the high-temperature evaporation chamber is 60kPa-120kPa.

[0013] Preferably, the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel includes at least one high temperature resistant tube, the high temperature resistant tube has a shell on the periphery, a liquid cooling interlayer is arranged in the shell, a thermal insulation layer and / or a secondary auxiliary heater is arranged between the shell and the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel, the ratio of the single-side thickness F1 of the tube wall of the high temperature resistant tube to the inner diameter D1 of the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel is 1:2-12, the ratio of the single-side thickness F1 of the tube wall of the high temperature resistant tube to the thickness F2 of the thermal insulation layer is 1:0.1-5; the ratio of the single-side wall thickness F3 of the single-layer or multi-layer main crucible to the single-side thickness F1 of the tube wall of the high temperature resistant tube is 1:0.2-0.9; the secondary auxiliary heater is laid on the entire section or partial section of the outer side of the high temperature resistant tube, and the high temperature resistant tube is made of any one of graphite, corundum, mica, zirconium oxide, aluminum oxide, and nitride ceramics.

[0014] By adopting the above technical solution, the shell has a liquid cooling interlayer, which can improve the safety of the equipment.

[0015] Preferably, a conductive channel for a conductive rod to pass through is provided at the lower part of the crucible body. After the solid metal in the main crucible is heated to become liquid, the ratio of the maximum diameter D of the metal liquid surface to the inner diameter d1 of the conductive channel is 1:0.01-0.3, and the ratio of the maximum diameter D of the metal liquid surface to the height H of the main crucible is 1:0.2-0.99. The crucible cover is provided with a feeding channel connected to the high-temperature evaporation chamber, and the ratio of the inner diameter D1 of the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel to the inner diameter D4 of the feeding channel is 1:0.1-1.0.

[0016] Preferably, the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel includes an equal-diameter channel, one end of the equal-diameter channel is connected to the high-temperature evaporation chamber, and the other end of the equal-diameter channel is connected to the expanded metal particle controller and then connected to the metal particle collector through the rear discharge channel; an air-cooled nozzle is provided at the equal-diameter channel and the expanded metal particle controller, and the air-cooled nozzle sprays cooling gas toward the center of the expanded metal particle controller, the inner cavity temperature of the expanded metal particle controller is below 300°C, and a barrier metal particle protection cover is provided on the outside of the air-cooled nozzle, the inner side of the barrier metal particle protection cover is a columnar or conical or Laval tubular structure, and the temperature in the equal-diameter channel is above 300°C.

[0017] Preferably, the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel includes an expansion channel, the expansion channel includes a metal vapor nucleation droplet section and a metal particle control section, the large diameter end of the metal vapor nucleation droplet section is connected to the metal particle control section, the diameter ratio of the small diameter end of the metal vapor nucleation droplet section to the large diameter end is 1:1.1-4, an air-cooling nozzle is arranged between the large diameter end of the metal vapor nucleation droplet section and the metal particle control section, the air-cooling nozzle sprays cooling gas toward the center direction of the expansion metal particle controller or the cooling gas directly enters the expansion metal particle controller.

[0018] Preferably, the crucible cover is conical, and the ratio of the maximum inner diameter D5 of the crucible cover to the inner diameter D1 of the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel is 1:0.25-0.68; a transfer arc gun channel for the plasma transfer arc gun to pass through is provided at the top of the crucible cover in the vertical direction; the ratio of the maximum diameter D of the metal liquid surface to the inner diameter D2 of the transfer arc gun channel is 1:0.2-1; the ratio of the maximum outer diameter D6 of the crucible cover to the maximum diameter D of the metal liquid surface of the main crucible is 1:0.9-1.6; the ratio of the maximum diameter D of the metal liquid surface of the main crucible to the outer diameter d2 of the lower end of the main crucible is 1:0.1-0.8; the ratio of the maximum inner diameter D5 of the crucible cover to the inner diameter D2 of the transfer arc gun channel is 1:0.3-1.

[0019] Preferably, the main crucible includes a crucible body and a buffer filling layer, the buffer filling layer is located on the outside of the crucible body, a protective layer is provided on the outside of the crucible body, the buffer filling layer is located between the crucible body and the protective layer, the sum of the thickness of the single-side wall thickness F3 of the main crucible and the thickness of the single-side wall thickness of the protective layer is F4, and the ratio of the maximum diameter D of the metal liquid surface of the main crucible to (F3+F4) is 1:0.1-0.9.

[0020] Preferably, a carrier gas inlet is connected to the high-temperature evaporation chamber, and the carrier gas inlet is located at the lowest part of the end of the high-temperature evaporation chamber and the height difference with the metal evaporation liquid level is greater than 10 mm. The carrier gas used is a recycled inert gas heated by an auxiliary heater.

[0021] Preferably, the expanded diameter metal particle controller is connected to a sampling tube, a valve one is provided on the sampling tube, the sampling tube is connected to a sampler via a quick connector, the other end of the sampler is connected to an exhaust pipe via a quick connector, a metal filter plate / net is provided in the sampler, a valve two is provided on the exhaust pipe, and the exhaust pipe is connected to a vacuum suction device.

[0022] Preferably, the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel has an equal-diameter channel or an expanded-diameter channel for spraying cooling gas into the channel, and the cooling gas distributor is a gas distributor that is directly pushed into the channel and / or a distributor that sprays cooling gas from the inner wall of the channel.

[0023] In summary, this application includes the following beneficial technical effects:

[0024] The main crucible and / or the crucible cover are provided with an auxiliary heating device on the periphery, which can heat the high-temperature evaporation chamber. Even if the diameter of the plasma arc column of the plasma transfer arc gun remains unchanged, the metal liquid surface at the edge can still be effectively heated and reach the boiling point temperature, so that the proportion of the evaporation cross-sectional area of ​​the metal liquid surface becomes larger, thereby improving the preparation capacity of metal particles. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a cross-sectional view of the first embodiment of the present application.

[0026] Figure 2 yes Figure 1 Enlarged view of part A.

[0027] Figure 3 yes Figure 1 Enlarged view of part B.

[0028] Figure 4 It is a cross-sectional view of the second embodiment of the present application.

[0029] Explanation of the reference numerals in the accompanying drawings: 1. plasma transfer arc gun; 2. carrier gas inlet; 3. sampler; 31. sampling tube; 32. exhaust tube; 4. main crucible; 5. crucible cover; 6. high-temperature evaporation chamber; 7. metal vapor outlet and channel or metal nucleation channel or metal vapor nucleation droplet channel; 8. auxiliary heating device; 9. auxiliary electrode; 10. high-temperature resistant tube; 11. shell; 12. liquid cooling interlayer; 13. secondary auxiliary heater; 14. conductive rod; 15. conductive channel; 16. feeding channel; 7-1. equal-diameter channel; 18. expanded diameter metal particle controller; 19. transfer arc gun channel; 20. crucible body; 21. buffer filling layer; 22. protective layer; 23. rear discharge channel; 7-2. expanded diameter channel; 25. air-cooled nozzle; 25-1. barrier metal particle protective cover; 26. metal vapor nucleation droplet section; 27. metal particle control section; 28. furnace body. DETAILED DESCRIPTION

[0030] The following is combined with Figure 1-4 This application is described in further detail.

[0031] Embodiment 1:

[0032] like Figure 1 , Figure 2 , Figure 3 As shown, a high temperature reactor for preparing metal particles by plasma arc, the high temperature reactor comprises a furnace body 28 and a plasma transfer arc gun 1.

[0033] Specifically, the shell of the furnace body 28 has a cooling layer, which is connected to a coolant inlet and a coolant outlet. The furnace body 28 has a main crucible 4 and a crucible cover 5. The crucible cover 5 is located above the main crucible 4. The two are combined to form a high-temperature evaporation chamber 6. The main crucible 4 is used to hold solid metal, which can become liquid metal after heating.

[0034] The high temperature evaporation chamber 6 is connected with a carrier gas inlet 2, which is located at the lowest part of the inner end of the high temperature evaporation chamber 6 and has a height difference of more than 10 mm from the metal evaporation liquid surface. The carrier gas used is a circulating inert gas heated by an auxiliary heater.

[0035] The plasma transfer arc gun 1 extends into the furnace body 28 and extends through the crucible cover 5 to the high-temperature evaporation chamber 6. The plasma transfer arc gun 1 is coated with thermal insulation materials and high-temperature resistant materials. The gas heated by the plasma transfer arc gun 1 includes inert gas and / or hydrogen. The working voltage of the plasma transfer arc gun 1 is 100-220V, the working current is 350-1200A, and the pressure in the high-temperature evaporation chamber 6 is 60kPa-120kPa.

[0036] The high-temperature evaporation chamber 6 is connected to the carrier gas inlet 2 and the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel 7, and the carrier gas inlet 2 and the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel 7 are connected to the high-temperature evaporation chamber 6.

[0037] Preferably, in the present embodiment, the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel 7 is arranged on the crucible cover 5. As another scheme, the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel 7 can be arranged on the main crucible 4, or partially connected to the crucible cover 5 and partially connected to the main crucible 4.

[0038] The outer periphery of the main crucible 4 and / or the crucible cover 5 is provided with an auxiliary heating device 8 capable of heating the high-temperature evaporation chamber 6. The ratio of the maximum diameter D of the metal liquid surface of the main crucible 4 to the inlet inner diameter D1-1 of the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel 7 is 1:0.2-0.8.

[0039] The stacking height H2 is the sum of the height H1 of the crucible cover 5 and the height H3 of the transfer arc gun channel 19 in the furnace body 28. The ratio of the inlet inner diameter D1-1 of the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel 7 to the stacking height H2 is 1:2-15.

[0040] It should be noted that the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel 7 has different names according to the different states of the metal in the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel 7: if the metal in the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel 7 is in a vapor state, then the channel is the metal vapor outlet and channel; if metal particles nucleate in the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel 7, then the channel is the metal nucleation channel; if the metal gradually nucleates from a droplet state in the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel 7, then the channel is the metal vapor nucleation droplet channel.

[0041] Preferably, the auxiliary heating device 8 includes a resistance heater, which is located outside the main crucible 4, and is connected to an auxiliary electrode 9, which is connected to a water cooling device. The resistance heater is a heating graphite used to heat the molten metal in the high-temperature reactor.

[0042] As another solution, the auxiliary heating device 8 includes a high frequency induction heater or a medium frequency induction heater for heating the molten metal in the high temperature reactor. The distance between the auxiliary heating device 8 and the outer wall of the main crucible 4 is 1-250 mm, preferably 5-50 mm.

[0043] The metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel 7 includes at least one high temperature resistant tube 10. In this embodiment, a plurality of high temperature resistant tubes 10 are provided.

[0044] The high temperature resistant tube 10 has a shell 11 on the periphery, a liquid cooling interlayer 12 is arranged in the shell 11, a thermal insulation layer and / or a secondary auxiliary heater 13 is arranged between the shell 11 and the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel 7, and the secondary auxiliary heater 13 is laid on the entire section or partial area of ​​the outer side of the high temperature resistant tube 10. The secondary auxiliary heater 13 can adopt resistance heating or induction heating.

[0045] The ratio of the single-side thickness F1 of the tube wall of the high-temperature resistant tube 10 to the inner diameter D1 of the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel 7 is 1:2-12, and the ratio of the single-side thickness F1 of the tube wall of the high-temperature resistant tube 10 to the thickness F2 of the thermal insulation layer is 1:0.1-5; the ratio of the single-side wall thickness F3 of the single-layer or multi-layer main crucible 4 to the single-side thickness F1 of the tube wall of the high-temperature resistant tube 10 is 1:0.2-0.9; the high-temperature resistant tube 10 is made of any one of graphite, corundum, mica, zirconium oxide, aluminum oxide, and nitride ceramics.

[0046] A conductive channel 15 is provided at the lower part of the crucible body 20 for the conductive rod 14 to pass through. After the solid metal in the main crucible 4 is heated to become liquid, the ratio of the maximum diameter D of the metal liquid surface to the inner diameter d1 of the conductive channel 15 is 1:0.01-0.3, and the ratio of the maximum diameter D of the metal liquid surface to the height H of the main crucible 4 is 1:0.2-0.99. The crucible cover 5 is provided with a feeding channel 16 connected to the high-temperature evaporation chamber 6, and the ratio of the inner diameter D1 of the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel 7 to the inner diameter D4 of the feeding channel 16 is 1:0.1-1.0.

[0047] In this embodiment, the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel 7 includes an equal-diameter channel 7-1, one end of the equal-diameter channel 7-1 is connected to the high-temperature evaporation chamber 6, and the other end of the equal-diameter channel 7-1 is connected to the expanded metal particle controller 18 and then connected to the metal particle collector through the rear discharge channel 23. An air-cooled nozzle 25 is provided at the equal-diameter channel 7-1 and the expanded metal particle controller 18. The air-cooled nozzle 25 sprays cooling gas toward the center of the expanded metal particle controller 18. The inner cavity temperature of the expanded metal particle controller 18 is below 300°C. A barrier metal particle protection cover 25-1 is provided on the outside of the air-cooled nozzle 25. The inner side of the barrier metal particle protection cover 25-1 is a columnar or conical or Laval tubular structure. The temperature in the equal-diameter channel 7-1 is above 300°C.

[0048] The metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel 7 has a cooling gas distributor 73 in the equal-diameter channel 7-1 to spray cooling gas into the channel. The cooling gas distributor 73 is a gas distributor that is directly pushed into the channel and / or a distributor that sprays cooling gas from the inner wall of the channel. The cooling gas distributor 73 sprays cooling gas into the equal-diameter channel 7-1 to accelerate the nucleation of metal particles in the equal-diameter channel 7-1.

[0049] The expanded diameter metal particle controller 18 is connected to a sampling tube 31, a valve 1 is provided on the sampling tube 31, the sampling tube 31 is connected to a sampler 3 through a quick connector, the other end of the sampler 3 is connected to an exhaust pipe 32 through a quick connector, a metal filter plate / net is provided in the sampler 3, a valve 2 is provided on the exhaust pipe 32, and the exhaust pipe 32 is connected to a vacuum suction device.

[0050] When in use, the vacuum suction device connected to the exhaust pipe 32 is started, and valve 1 and valve 2 are opened at the same time, so that the metal particles in the expanded diameter metal particle controller 18 can be sucked into the sampler 3, and the metal particles are then blocked by the metal filter plate / net in the sampler 3 and remain in the sampler 3. After closing the vacuum suction device, valve 1 and valve 2, the sampler 3 can be removed through the quick connector, and the metal particles in the sampler 3 can be detected later, thereby realizing real-time detection of the metal particles produced by the equipment.

[0051] In this embodiment, the crucible cover 5 is conical, and the ratio of the maximum inner diameter D5 of the crucible cover 5 to the inner diameter D1 of the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel 7 is 1:0.25-0.68. The top of the crucible cover 5 is provided with a transfer arc gun channel 19 for the plasma transfer arc gun 1 to pass through in the vertical direction. The ratio of the maximum diameter D of the metal liquid surface to the inner diameter D2 of the transfer arc gun channel 19 is 1:0.2-1. The ratio of the maximum outer diameter D6 of the crucible cover 5 to the maximum diameter D of the metal liquid surface of the main crucible 4 is 1:0.9-1.6; the ratio of the maximum diameter D of the metal liquid surface of the main crucible 4 to the outer diameter d2 of the lower end of the main crucible 4 is 1:0.1-0.8, and the ratio of the maximum inner diameter D5 of the crucible cover 5 to the inner diameter D2 of the transfer arc gun channel 19 is 1:0.3-1.

[0052] In this embodiment, the main crucible 4 includes a crucible body 20 and a buffer filling layer 21, the buffer filling layer 21 is located on the outside of the crucible body 20, a protective layer 22 is provided on the outside of the crucible body 20, the buffer filling layer 21 is located between the crucible body 20 and the protective layer 22, the sum of the thickness of the single-side wall thickness F3 of the main crucible 4 and the thickness of the single-side wall thickness of the protective layer 22 is F4, and the ratio of the maximum diameter D of the metal liquid surface of the main crucible 4 to (F3+F4) is 1:0.1-0.9.

[0053] The working principle of this embodiment is as follows: the solid-liquid metal is placed in the high-temperature evaporation chamber 6, and the plasma transfer arc gun 1 forms a loop with the solid metal in the main crucible 4 to melt and evaporate the solid metal in the high-temperature evaporation chamber 6. Since the main crucible 4 and / or the crucible cover 5 are provided with an auxiliary heating device 8 on the periphery, the high-temperature evaporation chamber 6 can be heated. Even if the diameter of the plasma arc column of the plasma transfer arc gun 1 remains unchanged, the metal liquid surface at the edge can still be effectively heated and reach the boiling point temperature, so that the proportion of the evaporation cross-sectional area of ​​the metal liquid surface in the high-temperature evaporation chamber 6 becomes larger, thereby improving the production capacity of metal particles.

[0054] In order to better illustrate the effect of this embodiment, the following comparative description is used:

[0055] Solution 1: Check the airtightness of the reaction system, turn on the exhaust fan and vacuum system, fill the system with inert gas, the plasma gun air intake is 3.8m³ / h, the inner diameter of the crucible is 220mm, so that the system reaches a negative pressure state of 80kPa, the oxygen content is less than 1000ppm, ignite the plasma arc, use an input voltage of 100V and a current of 500A, preheat for 5 hours, and then adjust the plasma arc voltage to 160V and the current to 800A. The experiment produces metal particles, and the measured metal particle output is 4000g / h, and the total working power is 158kW.

[0056] Option 2: Check the airtightness of the reaction system, turn on the exhaust fan and vacuum system, fill the system with inert gas, the air intake is 3.8m³ / h, the inner diameter of the crucible is 220mm, so that the system reaches a negative pressure state of 80kPa, the oxygen content is less than 1000ppm, ignite the plasma arc, use an input voltage of 100V and a current of 500A, preheat for 5 hours, and then adjust the plasma arc voltage to 160V and the current to 800A, turn on high-frequency heating for auxiliary heating (voltage 50V, current 400A), and the output of metal particles is measured to be 6000g / h, and the total working power is 178kW.

[0057] After comparison, the output of Plan 2 is much higher than that of Plan 1, and the required power is only increased by 20kW. The small power increase brings a large increase in output, and the energy consumption per unit of output is significantly reduced, with obvious energy-saving effects.

[0058] Embodiment 2:

[0059] The difference between this embodiment and the first embodiment is that Figure 4 As shown, in this embodiment, the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel 7 includes an expanded diameter channel 7-2, rather than an equal diameter channel 7-1. The expanded diameter channel 7-2 includes a metal vapor nucleation droplet section 26 and a metal particle control section 27. The large diameter end of the metal vapor nucleation droplet section 26 is connected to the metal particle control section 27. The ratio of the diameter of the small diameter end to the diameter of the large diameter end of the metal vapor nucleation droplet section 26 is 1:1.1-4. The inner diameter D1 of the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel 7 is understood to be the average inner diameter of the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel 7. An air cooling nozzle 25 is provided between the large diameter end of the metal vapor nucleation droplet section 26 and the metal particle control section 27. The air cooling nozzle 25 sprays cooling gas toward the center of the expanded diameter metal particle controller 18 or the cooling gas directly enters the expanded diameter metal particle controller 18.

[0060] The expansion channel 7-2 of the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel 7 has a cooling gas distributor 73 to spray cooling gas into the channel. The cooling gas distributor 73 is a gas distributor directly pushed into the channel and / or a distributor that sprays cooling gas from the inner wall of the channel. The cooling gas distributor 73 sprays cooling gas into the expansion channel 7-2 to accelerate the nucleation of metal particles in the expansion channel 7-2.

[0061] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A high temperature reactor for preparing metal particles using a plasma arc, characterized in that: The high-temperature reactor comprises a furnace body (28) and a plasma transfer arc gun (1). The furnace body (28) is provided with a main crucible (4) and a crucible cover (5). The crucible cover (5) is located above the main crucible (4). The two are combined to form a high-temperature evaporation chamber (6). The plasma transfer arc gun (1) extends into the furnace body (28) and passes through the crucible cover (5) to extend into the high-temperature evaporation chamber (6). The plasma transfer arc gun (1) is coated with a heat-insulating material and a high-temperature resistant material. The high-temperature evaporation chamber (6) is connected to a carrier gas inlet (2) and a metal vapor outlet and a channel or a metal nucleation channel or a metal vapor nucleation channel. A nucleation droplet channel (7), a metal vapor outlet and channel or a metal nucleation channel or a metal vapor nucleation droplet channel (7) are arranged on a crucible cover (5) and / or a main crucible (4), and are connected to a high-temperature evaporation chamber (6); the periphery of the main crucible (4) and / or the crucible cover (5) is provided with an auxiliary heating device (8) capable of heating the high-temperature evaporation chamber (6); the ratio of the maximum diameter D of the metal liquid surface of the high-temperature reactor to the inlet inner diameter D1-1 of the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel (7) is 1:0.2-0.8; The stacking height H2 is the sum of the height H1 of the crucible cover (5) and the height H3 of the transfer arc gun channel (19) in the furnace body (28), and the ratio of the inlet inner diameter D1-1 of the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel (7) to the stacking height H2 is 1:2-15.

2. A high temperature reactor for preparing metal particles by plasma arc according to claim 1, characterized in that: The auxiliary heating device (8) comprises a resistance heater, which is located outside the main crucible (4), is connected to an auxiliary electrode (9), and is connected to a water cooling device. The resistance heater is a heating graphite used to heat the metal melt in the high-temperature reactor. Alternatively, the auxiliary heating device (8) comprises a high-frequency induction heater or a medium-frequency induction heater, which is used to heat the molten metal in the high-temperature reactor, and the distance between the auxiliary heating device (8) and the outer wall surface of the main crucible (4) is 1-250 mm.

3. A high temperature reactor for preparing metal particles by plasma arc according to claim 1, characterized in that: The working voltage of the plasma transfer arc gun (1) is 100-220V, and the working current is 350-1200A; the pressure in the high-temperature evaporation chamber (6) is 60kPa-120kPa.

4. A high temperature reactor for preparing metal particles by plasma arc according to claim 1, characterized in that: The metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel (7) comprises at least one high temperature resistant tube (10), the high temperature resistant tube (10) has a shell (11) on its periphery, a liquid cooling interlayer (12) is arranged in the shell (11), a heat preservation and insulation layer and / or a secondary auxiliary heater (13) is arranged between the shell (11) and the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel (7), the single side thickness F1 of the tube wall of the high temperature resistant tube (10) is equal to the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel (7), and the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel (7) is equal to the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel (7). The ratio of the inner diameter D1 of the core droplet channel (7) is 1:2-12; the ratio of the single-side thickness F1 of the tube wall of the high-temperature resistant tube (10) to the thickness F2 of the thermal insulation layer is 1:0.1-5; the ratio of the single-side wall thickness F3 of the single-layer or multi-layer main body crucible (4) to the single-side wall thickness F1 of the high-temperature resistant tube (10) is 1:0.2-0.9; the secondary auxiliary heater (13) is laid on the entire section or a partial section of the outer side of the high-temperature resistant tube (10); the high-temperature resistant tube (10) is made of any one of graphite, corundum, mica, zirconium oxide, aluminum oxide, and nitride ceramics.

5. A high temperature reactor for preparing metal particles by plasma arc according to claim 4, characterized in that: A conductive channel (15) for a conductive rod (14) to pass through is provided at the bottom of the crucible body (20); after the solid metal in the main crucible (4) is heated to become liquid, the ratio of the maximum diameter D of the metal liquid surface to the inner diameter d1 of the conductive channel (15) is 1:0.01-0.3, and the ratio of the maximum diameter D of the metal liquid surface to the height H of the main crucible (4) is 1:0.2-0.

99. The crucible cover (5) is provided with a feeding channel (16) connected to the high-temperature evaporation chamber (6); the ratio of the inner diameter D1 of the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel (7) to the inner diameter D4 of the feeding channel (16) is 1:0.1-1.

0.

6. A high temperature reactor for preparing metal particles by plasma arc according to claim 5, characterized in that: The metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel (7) comprises an equal-diameter channel (7-1), one end of which is connected to the high-temperature evaporation chamber (6), and the other end of which is connected to the expanded diameter metal particle controller (18) and then connected to the metal particle collector via the rear discharge channel (23); an air-cooling nozzle (25) is arranged at the equal-diameter channel (7-1) and the expanded diameter metal particle controller (18), the air-cooling nozzle (25) sprays cooling gas toward the center of the expanded diameter metal particle controller (18), the inner cavity temperature of the expanded diameter metal particle controller (18) is below 300° C., a barrier metal particle protection cover (25-1) is arranged on the outer side of the air-cooling nozzle (25), the inner side of the barrier metal particle protection cover (25-1) is a columnar or conical or Laval tubular structure, and the temperature in the equal-diameter channel (7-1) is above 300° C.

7. A high temperature reactor for preparing metal particles by plasma arc according to claim 5, characterized in that: The metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel (7) comprises an expansion channel (7-2), the expansion channel (7-2) comprises a metal vapor nucleation droplet section (26) and a metal particle control section (27), the large diameter end of the metal vapor nucleation droplet section (26) is connected to the metal particle control section (27), the diameter ratio of the small diameter end to the large diameter end of the metal vapor nucleation droplet section (26) is 1:1.1-4, an air cooling nozzle (25) is arranged between the large diameter end of the metal vapor nucleation droplet section (26) and the metal particle control section (27), and the air cooling nozzle (25) sprays cooling gas toward the center direction of the expansion metal particle controller (18) or the cooling gas directly enters the expansion metal particle controller (18).

8. A high temperature reactor for preparing metal particles by plasma arc according to claim 7, characterized in that: The crucible cover (5) is conical, and the ratio of the maximum inner diameter D5 of the crucible cover (5) to the inner diameter D1 of the metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel (7) is 1:0.25-0.

68. A transfer arc gun channel (19) for the plasma transfer arc gun (1) to pass through is provided on the top of the crucible cover (5) in the vertical direction. The ratio of the maximum diameter D of the metal liquid surface to the inner diameter D2 of the transfer arc gun channel (19) is 1:0.2-1. The ratio of the maximum outer diameter D6 of the crucible cover (5) to the maximum diameter D of the metal liquid surface of the main crucible (4) is 1:0.9-1.

6. The ratio of the maximum diameter D of the metal liquid surface of the main crucible (4) to the outer diameter d2 of the lower end of the main crucible (4) is 1:0.1-0.

8. The ratio of the maximum inner diameter D5 of the crucible cover (5) to the inner diameter D2 of the transfer arc gun channel (19) is 1:0.3-1.

9. A high temperature reactor for preparing metal particles by plasma arc according to claim 8, characterized in that: The main crucible (4) comprises a crucible body (20) and a buffer filling layer (21), the buffer filling layer (21) is located outside the crucible body (20), a protective layer (22) is arranged outside the crucible body (20), the buffer filling layer (21) is located between the crucible body (20) and the protective layer (22), the sum of the thickness of the single-side wall thickness F3 of the main crucible (4) and the thickness of the single-side wall thickness of the protective layer (22) is F4, and the ratio of the maximum diameter D of the metal liquid surface of the main crucible (4) to (F3+F4) is 1:0.1-0.

9.

10. A high temperature reactor for preparing metal particles by plasma arc according to claim 1, characterized in that: A carrier gas inlet (2) is connected to the high-temperature evaporation chamber (6). The carrier gas inlet (2) is located at the lowest position of the inner end of the high-temperature evaporation chamber (6) and has a height difference of more than 10 mm from the metal evaporation liquid surface. The carrier gas used is a circulating inert gas heated by an auxiliary heater.

11. A high temperature reactor for preparing metal particles by plasma arc according to claim 6, characterized in that: The expanded diameter metal particle controller (18) is connected to a sampling tube (31), a valve 1 is arranged on the sampling tube (31), the sampling tube (31) is connected to a sampler (3) via a quick connector, the other end of the sampler (3) is connected to an exhaust pipe (32) via a quick connector, a metal filter plate / net is arranged in the sampler (3), a valve 2 is arranged on the exhaust pipe (32), and the exhaust pipe (32) is connected to a vacuum suction device.

12. A high temperature reactor for preparing metal particles by plasma arc according to claim 1, characterized in that: The metal vapor outlet and channel or the metal nucleation channel or the metal vapor nucleation droplet channel (7) has a cooling gas distributor (73) in the equal-diameter channel (7-1) or the expanded-diameter channel (7-2) for spraying cooling gas into the channel. The cooling gas distributor (73) is a gas distributor that is directly pushed into the channel and / or a distributor that sprays cooling gas from the inner wall of the channel.

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