Device for purifying carbon nano tube at high temperature

Abstract

The invention provides a device for purifying a carbon nano tube at high temperature. The device comprises an inert gas conveying pipe, a high-temperature furnace, an impurity collecting tank, a powder separator, a multi-stage vacuum system and a waste gas discharging pipe. According to the device, gas conveying is adopted as the principle basis, a plurality of devices are connected to achieve continuous high-temperature purification of the carbon nanotubes under micro-positive pressure, the device is scientific in design, high in automation degree and capable of achieving continuous operation, the total metal content in a carbon nanotube purification product can be smaller than 100 ppm, and the device is suitable for industrial large-scale production.

Description

Technical Field

[0001] The present application relates to the field of carbon nanotube purification, and in particular to a device for high-temperature purification of carbon nanotubes. Background Art

[0002] Carbon nanotubes, as a special carbon nanomaterial with a high aspect ratio and a hollow tubular structure, can be regarded as a one-dimensional quantum material composed of single or multiple layers of graphene layers curled around a central axis at a certain spiral angle. Carbon nanotubes have excellent physical and mechanical properties and outstanding chemical stability due to their special structure, and exhibit unique properties in mechanics, electricity, electrical conductivity and thermal conductivity. Therefore, carbon nanotubes have broad application prospects in many fields such as battery energy storage, homogeneous catalyst carriers, rubber composites, and optoelectronic sensors.

[0003] The current mainstream carbon nanotube preparation process is chemical vapor deposition, but the resulting crude carbon nanotube product will inevitably carry metal catalyst particles, and the purity of the carbon nanotube product has a significant impact on its many applications in electrochemical energy storage, composite materials, etc. For example, in high-end power batteries, metal impurities will increase the self-discharge of power lithium batteries, increase the safety risks of the battery and reduce the service life of the battery. Therefore, the crude carbon nanotubes must be purified to obtain high-purity carbon nanotubes. In the related art, the carbon nanotube purification methods include liquid phase pickling, vacuum high-temperature purification, etc., but the pickling purification effect is not good and it is easy to produce a large amount of sewage; vacuum high-temperature purification is usually carried out in a vacuum environment, which has high requirements for equipment and cannot be produced continuously, resulting in high energy consumption, low production capacity, and high cost.

[0004] Therefore, carbon nanotube purification technology still needs to be improved. Summary of the invention

[0005] The present application aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the present application proposes a device for continuous high-temperature purification of carbon nanotubes based on the principle of gas transportation. The above-mentioned device of the present application has the advantages of being able to realize continuous operation, scientific design or high degree of automation, and is suitable for industrial-scale production.

[0006] In one aspect of the present application, the present application provides a device for high-temperature purification of carbon nanotubes. According to an embodiment of the present application, the device includes: an inert gas delivery pipe for providing inert gas; a preheater, the top of which is connected to the inert gas delivery pipe, for preheating the material to be purified; a high-temperature furnace, connected to the inert gas delivery pipe and the preheater, for high-temperature purification of the preheated material to be purified; an impurity collection tank, connected to the high-temperature furnace, for collecting metal impurities; a powder separator, connected to the high-temperature furnace, for separating and purifying the material; a multi-stage vacuum system, connected to the impurity collection tank and the powder separator, for providing driving force for the transmission of the metal impurity vapor from the high-temperature furnace to the impurity collection tank and the transmission of the purified material from the high-temperature furnace to the powder separator; an exhaust gas discharge pipe, connected to the preheater, the impurity collection tank and the multi-stage vacuum system, for discharging tail gas.

[0007] According to an embodiment of the present application, the device also includes a raw material tank, on which are provided: a raw material tank inert gas inlet, connected to the inert gas delivery pipe, for inputting inert gas into the raw material tank; a raw material tank inert gas outlet, for discharging the inert gas from the raw material tank; a raw material tank feed port, for inputting the material to be purified into the raw material tank; a raw material tank discharge port, for outputting the material to be purified from the raw material tank; a material level meter, for detecting the storage amount of the material to be purified in the raw material tank; a raw material tank oxygen content monitor, for monitoring the oxygen content in the raw material tank; a raw material tank powder filtering device, provided at the inert gas outlet of the raw material tank, for filtering the material to be purified.

[0008] According to an embodiment of the present application, a replacement gas outlet control valve is provided between the multi-stage vacuum system and the raw material tank.

[0009] According to an embodiment of the present application, the preheater is provided with: a preheater inert gas inlet, located at the bottom of the preheater and connected to the inert gas delivery pipe, for introducing the inert gas into the preheater; a preheater tail gas outlet, located at the top of the preheater, for discharging the tail gas in the preheater; a preheater backflush gas inlet, located at the top of the preheater, for introducing backflush gas into the preheater; a preheater feed port, for conveying the material to be purified into the preheater; a preheater discharge port, for outputting the preheated material to be purified out of the preheater; a heating device, located on the side wall of the preheater, for preheating the material to be purified; a cyclone separator, located at the top of the preheater, connected to the preheater tail gas outlet, for separating the material to be purified and the inert gas; a gas distribution plate, located between the preheater inert gas inlet and the heating device, for distributing the inert gas to fluidize the material to be purified.

[0010] According to an embodiment of the present application, the high temperature furnace comprises, from inside to outside, a graphite reaction chamber wall, an insulation layer, a heating device, a heat-resistant lining and a circulating cooling water jacket, wherein the graphite reaction chamber wall defines a purification reaction chamber.

[0011] According to an embodiment of the present application, the high-temperature furnace is provided with: a high-temperature furnace feed port, located at the top of the high-temperature furnace and connected to the preheater discharge port, for conveying the preheated material to be purified to the high-temperature furnace; a high-temperature furnace discharge port, located at the top of the high-temperature furnace, for outputting impurities and purified materials out of the high-temperature furnace; a high-temperature furnace oxygen content monitor, located at the top of the high-temperature furnace, for detecting the oxygen content in the high-temperature furnace; and a temperature measuring device, for detecting the temperature in the high-temperature furnace.

[0012] According to an embodiment of the present application, the impurity collecting tank is provided with: an impurity collecting tank air inlet, located at the top of the impurity collecting tank and connected to the discharge port of the high-temperature furnace, for conveying metal impurity vapor to the impurity collecting tank; a slag removal port, located at the bottom of the impurity collecting tank, for discharging impurity slag from the impurity collecting tank; an impurity collecting tank tail gas outlet, for discharging tail gas from the impurity collecting tank; an impurity collecting tank filter device, located at the tail gas outlet of the impurity collecting tank, for filtering the impurity slag; a cooling jacket, located on the outer side wall of the impurity collecting tank, for cooling the metal impurity vapor.

[0013] According to an embodiment of the present application, the discharge port of the preheater, the inert gas delivery pipe and the feed port of the high-temperature furnace are connected through a second three-way valve; and / or the discharge port of the high-temperature furnace, the feed port of the impurity collection tank and the feed port of the powder separator are connected through a first three-way valve.

[0014] According to an embodiment of the present application, the impurity collection tank and the high-temperature furnace are connected via an electric heating pipeline.

[0015] According to an embodiment of the present application, an exhaust gas control valve is provided between the impurity collection tank and the multi-stage vacuum system.

[0016] According to an embodiment of the present application, the powder separator is provided with: a powder separator feed port, located at the upper part of the powder separator and connected to the discharge port of the high-temperature furnace, for conveying the gas-solid mixture containing the purified material into the powder separator; a powder separator discharge port, located at the bottom of the powder separator, for outputting the purified material out of the powder separator; a powder separator tail gas outlet, located at the top of the powder separator, for discharging the tail gas in the powder separator; a powder separator backflush gas inlet, located at the top of the powder separator, connected to the inert gas delivery pipe, for introducing backflush gas into the powder separator; a powder separator filter device, located at the tail gas outlet of the powder separator, for filtering the purified material.

[0017] According to an embodiment of the present application, the powder separator and the high-temperature furnace are connected via a cooling pipe.

[0018] According to an embodiment of the present application, the multi-stage vacuum system includes 3-5 stages of vacuum pumps.

[0019] According to an embodiment of the present application, the inert gas delivery pipe includes a main pipe and a first branch pipe, a second branch pipe, a third branch pipe, and a fourth branch pipe connected to the main pipe; the first branch pipe is connected to the raw material tank and the bottom of the preheater, and the first branch pipe is provided with a preheater air inlet valve and a raw material tank air inlet valve; the second branch pipe is connected to the top of the preheater, and the second branch pipe is provided with a preheater back-blowing valve; the third branch pipe is connected to the high-temperature furnace, and the third branch pipe is provided with a high-temperature purification valve; the fourth branch pipe is connected to the powder separator, and the fourth branch pipe is provided with a powder separator back-blowing valve.

[0020] According to an embodiment of the present application, the device further comprises a product collection tank, which is connected to the powder separator and is used to collect the purified material.

[0021] Compared with the related art, this application has at least the following beneficial effects:

[0022] The present application combines multiple devices, uses inert gas to transport the raw carbon nanotubes to be purified and negative pressure to extract high-purity carbon nanotube products to complete continuous high-temperature purification of carbon nanotubes. The structure is simple and the design is scientific.

[0023] The present application can realize continuous operation through the coupling of a multi-stage vacuum system and a high-temperature furnace, and is suitable for industrial-scale production. A single system can purify 100 tons of carbon nanotubes annually. The high-purity carbon nanotube product obtained by the device of the present application has a purity of more than 99.9%, and the total metal content in the product is less than 100 ppm, with a significant purification effect.

[0024] The specific advantages are as follows:

[0025] (1) The present application controls the single batch purification processing volume by combining the switch control of the electric feed valve with the indication of the material level meter, thereby achieving quantitative processing, thereby ensuring the safe and stable operation of the device while maximizing the processing volume of the device;

[0026] (2) The present application provides an electric heating pipeline so that the metal impurity vapor is cooled and collected in the impurity collection tank, thereby avoiding condensation and blockage of the metal impurities in the pipeline and increasing the safety of the equipment;

[0027] (3) The present application adopts a negative pressure extraction method based on a multi-stage vacuum system to extract the high-purity carbon nanotube product, and collects the product after rapid cooling through a cooling pipe, thereby avoiding the need to stop the intermittent high-temperature furnace for material extraction, greatly reducing energy consumption and increasing economic efficiency;

[0028] (4) The present application reduces the complexity of pipeline design by setting up multiple three-way valves, simplifies the high-temperature furnace cavity structure, and improves the operability of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the structure of a device for purifying carbon nanotubes according to an embodiment of the present application.

[0030] Figure 2 It is a schematic diagram of the structure of a device for purifying carbon nanotubes according to an embodiment of the present application.

[0031] Figure 3 It is a schematic cross-sectional structure diagram of a high-temperature furnace in a device for purifying carbon nanotubes according to an embodiment of the present application. DETAILED DESCRIPTION

[0032] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, but cannot be understood as limiting the present application.

[0033] In one aspect of the present application, the present application provides a device for high temperature purification of carbon nanotubes. According to an embodiment of the present application, referring to Figure 1The device includes an inert gas delivery pipe 8 for providing inert gas; a preheater 2, the top of which is connected to the inert gas delivery pipe 8 and is used to preheat the material to be purified; a high-temperature furnace 3, which is connected to the inert gas delivery pipe 8 and the preheater 2, and is used to perform high-temperature purification on the preheated material to be purified; an impurity collection tank 4, which is connected to the high-temperature furnace 3 and is used to collect impurities; a powder separator 5, which is connected to the inert gas delivery pipe 8 and the high-temperature furnace 3 and is used to separate and purify the material; a multi-stage vacuum system, which is connected to the impurity collection tank and the powder separator, and is used to provide driving force for the transmission of the metal impurity vapor from the high-temperature furnace to the impurity collection tank and the transmission of the purified material from the high-temperature furnace to the powder separator; an exhaust gas discharge pipe 9, which is connected to the preheater 2, the impurity collection tank 4 and the multi-stage vacuum system 6, and is used to discharge tail gas. The above-mentioned device of the present application adopts gas transportation as the principle basis and connects multiple devices to achieve continuous high-temperature purification of carbon nanotubes under slightly positive pressure. The device is scientifically designed and highly automated, and can achieve continuous operation. The total metal content in the carbon nanotube purification product can be less than 100ppm, which is suitable for industrial-scale production.

[0034] Specifically, the device can work through the following steps: a predetermined amount of material to be purified is added into a preheater for preheating; the preheated material to be purified can be transported from the preheater to a high-temperature furnace with an inert gas as a back-blowing gas for a high-temperature purification reaction; during the reaction, the inert gas can carry the generated metal impurity vapor into the impurity collection tank; after the reaction is completed, the purified material can be transported to a powder separator under the action of a multi-stage vacuum system; after gas-solid separation, the inert gas can be used as a back-blowing gas to discharge the purified material from the powder separator, and the tail gas can be discharged into the exhaust gas discharge pipe through the multi-stage vacuum system.

[0035] According to the embodiments of the present application, referring to Figure 2 The device may further include a raw material tank 1, which is connected to the preheater 2 and is used to store the material to be purified. Specifically, the raw material tank 1 is connected to the inert gas transmission pipe 8 and the exhaust gas discharge pipe 9. The inert gas is introduced into the raw material tank 1 through the inert gas transmission pipe 8, and the gas in the raw material tank 1 is discharged through the exhaust gas discharge pipe 9. The raw material tank 1 can be gas-displaced to prevent oxidation damage to the material to be purified during the subsequent preheating or high-temperature purification process.

[0036] According to the embodiments of the present application, referring to Figure 2The raw material tank 1 may be provided with: a raw material tank inert gas inlet 101, connected to the inert gas delivery pipe 8, for inputting inert gas into the raw material tank 1; a raw material tank inert gas outlet 102, for discharging the inert gas from the raw material tank 1; an electric discharge gate valve 103, for controlling the switch for transmitting the material to be purified to the preheater 2; a raw material tank discharge port 104, for outputting the material to be purified from the raw material tank 1; a material level meter 105, for detecting the storage amount of the material to be purified in the raw material tank 1; a raw material tank oxygen content monitor 106, for monitoring the oxygen content in the raw material tank 1; a raw material tank powder filter 108, provided at the raw material tank inert gas outlet 102, for filtering the material to be purified.

[0037] According to the embodiments of the present application, referring to Figure 2 A replacement gas outlet control valve 60 is provided between the multi-stage vacuum system 6 and the raw material tank 1. When the raw material tank is replaced with inert gas, the replacement gas outlet control valve 60 is controlled to control the replacement rate and enhance the replacement effect, thereby ensuring that the oxygen content in the raw material tank is reduced as much as possible.

[0038] According to the embodiments of the present application, referring to Figure 2 The preheater is provided with: a preheater inert gas inlet 201, located at the bottom of the preheater, connected to the inert gas delivery pipe 8, for introducing the inert gas into the preheater; a preheater tail gas outlet 202, located at the top of the preheater, for discharging the tail gas in the preheater; a preheater backwash gas inlet 203, located at the top of the preheater, for introducing backwash gas into the preheater; a preheater feed port 204, for delivering the material to be purified into the preheater; The preheater discharge port 205 is used to output the preheated material to be purified out of the preheater; the heating device 206 is located on the side wall of the preheater and is used to preheat the material to be purified; the cyclone separator 207 is located at the top of the preheater and is connected to the preheater tail gas outlet and is used to separate the material to be purified and the inert gas; the gas distribution plate 208 is located between the inert gas inlet of the preheater and the heating device and is used to distribute the inert gas to fluidize the material to be purified.

[0039] Specifically, the material to be purified is transported to the preheater from the preheater feed port 204, and the inert gas is introduced into the preheater from the preheater inert gas inlet 201, and passes through the gas distributor 208, so that the material to be purified can be fluidized, thereby accelerating the preheating speed and improving the temperature uniformity. After reaching the preheating temperature, the inert gas can be stopped from being introduced from the preheater inert gas inlet 201, and the inert gas can be introduced from the preheater back-blowing gas inlet 203. Under the action of the back-blowing gas, the preheated material to be purified is transported to the high-temperature furnace.

[0040] According to the embodiments of the present application, referring to Figure 3 The high temperature furnace includes, from inside to outside, a graphite reaction chamber wall 31, a heat-insulating layer 32, a heating device 33, a heat-resistant lining 34 and a circulating cooling water jacket 35, wherein the graphite reaction chamber wall 31 defines a purification reaction chamber 36.

[0041] As an example, the high-temperature furnace graphite reaction chamber wall 31 is an integrated graphite structure with an overall thickness of 40mm-60mm. The purification reaction chamber 36 is cylindrical with an inner diameter of 400mm-600mm and a height of 700mm-1000mm. The top and bottom are spherical cap-shaped, and the longitudinal height of the spherical cap part is 150mm-300mm. The insulation layer 32 can be a graphite felt material. The heating form of the heating device 33 includes but is not limited to electromagnetic induction heating, resistance wire heating, radiation heating, or a combination thereof. The heat-resistant lining 34 can be a ceramic material, an aluminum silicate material, or a carbon composite refractory material. The circulating cooling water jacket 35 is used to control the temperature balance of the high-temperature furnace 3.

[0042] According to the embodiments of the present application, referring to Figure 2 The high temperature furnace 3 is provided with: a high temperature furnace feed port 301, located at the top of the high temperature furnace, connected to the preheater discharge port 205, for conveying the preheated material to be purified to the high temperature furnace; a high temperature furnace discharge port 302, located at the top of the high temperature furnace, for outputting impurities and purified materials from the high temperature furnace; a high temperature furnace oxygen content monitor 303, located at the top of the high temperature furnace, for detecting the oxygen content in the high temperature furnace; a temperature measuring device 304, for detecting the temperature in the high temperature furnace. Furthermore, a high temperature furnace inlet valve 30 and a vacuum gauge 29 are provided on the feed pipe of the high temperature furnace 3, and a high temperature furnace outlet valve 40 is provided on the discharge pipe.

[0043] According to the embodiments of the present application, referring to Figure 2 The discharge port 205 of the preheater, the inert gas transmission pipe 8 and the feed port 301 of the high temperature furnace are connected through the second three-way valve 20. Thus, the connection and closing between the preheater and the high temperature furnace, and between the inert gas transmission pipe and the high temperature furnace can be conveniently adjusted through the three-way valve.

[0044] According to the embodiments of the present application, referring to Figure 2 A tail gas control valve 70 is provided between the impurity collecting tank 4 and the multi-stage vacuum system 6. This can control the flow rate of the inert gas during the high-temperature purification reaction to prevent solid materials from being discharged from the high-temperature furnace along with the inert gas, and at the same time control the evaporation rate of metal impurities in the high-temperature furnace.

[0045] Specifically, after preheating is completed, the preheated material to be purified is transferred to the high-temperature furnace under the action of the backwash gas introduced into the preheater, and a high-temperature purification reaction is carried out at a predetermined temperature. During the reaction, an inert gas is continuously introduced into the high-temperature furnace. By controlling the opening of the tail gas control valve 70, the rate of the inert gas can be adjusted so that the inert gas can effectively carry the metal impurity vapor into the impurity collection tank, and the solid material will not be discharged from the high-temperature furnace. After the high-temperature purification reaction is completed, the high-temperature furnace inlet valve 30 is closed, and the high-temperature furnace outlet valve 40 is kept in an open state. Under the action of the multi-stage vacuum system, the purified material that has undergone high-temperature purification is transferred to the powder separator 5.

[0046] According to the embodiments of the present application, referring to Figure 2 The impurity collecting tank 4 is provided with: an impurity collecting tank air inlet 401, located at the top of the impurity collecting tank, connected to the high-temperature furnace discharge port 302, and used to transport the metal impurity vapor to the impurity collecting tank; a slag removal port 402, located at the bottom of the impurity collecting tank, and used to discharge the impurity slag from the impurity collecting tank; an impurity collecting tank tail gas outlet 403, used to discharge the tail gas from the impurity collecting tank; an impurity collecting tank filter device 404, located at the impurity collecting tank tail gas outlet, and used to filter the impurity slag; a cooling jacket 405, located on the outer side wall of the impurity collecting tank, and used to cool the metal impurity vapor.

[0047] According to the embodiments of the present application, referring to Figure 2 The impurity collecting tank 4 and the high temperature furnace 3 are connected through an electric heating pipeline 41. Thus, the metal impurity vapor can be prevented from cooling in the pipeline.

[0048] Specifically, during the high-temperature purification reaction, the inert gas can carry the impurity vapor through the electric heating pipe into the impurity collection tank, and under the action of the cooling jacket, the impurity vapor is cooled to obtain impurity slag. The impurity slag can be discharged from the impurity collection tank from the slag removal port.

[0049] According to the embodiments of the present application, referring to Figure 2 The powder separator 5 is provided with: a powder separator feed port 501, located at the upper part of the powder separator, connected with the high-temperature furnace discharge port 302, and used to convey the gas-solid mixture containing the purified material to the powder separator; a powder outlet 502, located at the bottom of the powder separator, and used to output the purified material from the powder separator; a powder separator tail gas outlet 503, located at the top of the powder separator, and used to discharge the tail gas in the powder separator; a powder separator backwash gas inlet 504, located at the top of the powder separator, and connected with the inert gas conveying pipe 8, and used to introduce backwash gas into the powder separator; a powder separator filter device 505, located at the tail gas outlet of the powder separator, and used to filter the purified material.

[0050] According to an embodiment of the present application, the discharge port 302 of the high-temperature furnace, the feed port 401 of the impurity collection tank, and the feed port 501 of the powder separator are connected through a first three-way valve.

[0051] According to the embodiments of the present application, referring to Figure 2 The powder separator 5 and the high temperature furnace 3 are connected through a cooling pipe 42. Thus, the purified material after purification from the high temperature furnace 3 can be effectively cooled for subsequent product collection. Specifically, the cooling pipe can be in the form of a jacket, and the circulating cooling liquid in the jacket is water or liquid nitrogen, and the total length can be 2m-4m.

[0052] Specifically, after the high-temperature purification reaction is completed, the purified material obtained is transported to the powder separator under the action of the multi-stage vacuum system. The powder separator can adopt a cyclone separation type. After the purified material is completely settled, the purified material can be output through the powder separator discharge port 502 under the action of the backwash gas.

[0053] According to an embodiment of the present application, the multi-stage vacuum system includes 3-5 stages of vacuum pumps. Specifically, by starting vacuum pumps of different stages and adjusting the system pressure, both gas replacement and solid material transmission can be achieved.

[0054] The multi-stage vacuum system 6 can be provided with 3-5 levels of vacuum pumps connected to provide different conveying power to meet the needs of different conditions. The multi-stage vacuum system 6 is provided with a vacuum system inlet 601 and a vacuum system tail gas outlet 602. The vacuum system inlet 601 can be connected with the raw material tank inert gas outlet 102, the impurity collection tank tail gas outlet 403 and the powder separator tail gas outlet 503, and is used to provide conveying power for materials (such as inert gas, materials to be purified, metal impurity vapor, gas-solid mixture containing purified materials, etc.). Further, a vacuum valve 50 is provided at the front end of the vacuum system inlet 601, and a replacement gas outlet control valve 60 is provided on the connecting pipeline between the vacuum valve 50 and the raw material tank inert gas outlet 102, which is used to control the force of gas discharge from the raw material tank 1, and a tail gas control valve 70 is provided on the connecting pipeline between the vacuum valve 50 and the impurity collection tank tail gas outlet 403, which is used to control the force of metal impurity vapor discharge.

[0055] The inert gas delivery pipe 8 is used to provide inert gas. The inert gas delivery pipe 8 may include a main pipe 81 and a first branch pipe 811, a second branch pipe 812, a third branch pipe 813, and a fourth branch pipe 814 connected to the main pipe 81; the first branch pipe 811 is connected to the raw material tank inlet 101 and the preheater inlet 201, and is used to pass inert gas into the raw material tank 1 and the preheater 2, and the first branch pipe 811 may be provided with a preheater air inlet valve 82 and a raw material tank air inlet valve 83, which are used to control the air intake into the preheater 2 and the raw material tank 1, respectively; the second branch pipe 812 is connected to the preheater backwash gas inlet 203, and is used to pass inert gas into the preheater 2. The second branch pipe 812 can be provided with a preheater back-blowing valve 84 for controlling the amount of back-blowing gas introduced into the preheater 2; the third branch pipe 813 is connected to the high-temperature furnace feed port 301, for introducing inert gas into the high-temperature furnace 3, and the third branch pipe 813 is provided with a high-temperature purification valve 85 for controlling the amount of inert gas introduced into the high-temperature furnace 3; the fourth branch pipe 814 is connected to the powder separator back-blowing gas inlet 504, for introducing inert gas into the powder separator as back-blowing gas, and the fourth branch pipe 814 is provided with a powder separator back-blowing valve 86 for controlling the amount of back-blowing gas introduced into the powder separator 5. Furthermore, the third branch pipe 813, the preheater outlet 205 and the high-temperature furnace feed port 301 are connected through the second three-way valve 20, and a high-temperature furnace inlet valve 30 is arranged between the second three-way valve 20 and the high-temperature furnace feed port 301, which is used to control whether to input materials into the high-temperature furnace 3, and a vacuum gauge is arranged between the high-temperature furnace inlet valve 30 and the high-temperature furnace feed port 301, which is used to detect the vacuum degree in the pipeline.

[0056] The waste gas discharge pipe 9 is connected with the raw material tank inert gas outlet 102, the preheater tail gas outlet 202, the impurity collection tank tail gas outlet 403 and the vacuum system tail gas outlet 602 for discharging tail gas.

[0057] According to the embodiments of the present application, referring to Figure 2 The device also includes a product collecting tank 7, which is connected to the powder separator 5 and is used to collect the purified material.

[0058] As an example, the device for high-temperature purification of carbon nanotubes according to the embodiment of the present application includes: a raw material tank 1, a preheater 2, a high-temperature furnace 3, an impurity collection tank 4, a powder separator 5, a multi-stage vacuum system 6, a product collection tank 7, an inert gas delivery pipe 8 and an exhaust gas discharge pipe 9. Among them:

[0059] The raw material tank 1 is used to store the material to be purified. The raw material tank 1 is provided with a raw material tank inert gas inlet 101, a raw material tank inert gas outlet 102, an electric discharge gate valve 103, a raw material tank discharge port 104, a material level meter 105, a raw material tank oxygen content monitor 106 and a raw material tank pressure gauge 107. The raw material tank inert gas outlet 102 is provided with a raw material tank powder filtering device 108; the raw material tank inert gas inlet 101 and the raw material tank inert gas outlet 102 are respectively used to input and output inert gas into the raw material tank 1 to maintain the inert gas atmosphere in the raw material tank 1, and the rear end of the raw material tank inert gas outlet 102 is provided with a raw material tank outlet valve 80 for controlling whether to discharge gas from the raw material tank 1; the electric discharge gate valve 103 is used to quantitatively control the single batch inlet and outlet. The amount of material to be purified introduced into the preheater 2, that is, the amount of high-temperature purified raw materials in a single batch, is used to maximize and safely utilize the volume of the high-temperature furnace reaction chamber; the raw material tank outlet 104 is used to output the material to be purified; the level meter 105 is used to detect the storage amount of the material to be purified in the raw material tank 1, and multiple levels can be arranged in sequence in the height direction of the raw material tank 1, such as 2, 3, 4, 5, 6, etc. As an example, three level meters 105 can be set; the first oxygen content monitor 106 can be arranged at the top of the raw material tank 1 to monitor the oxygen content in the raw material tank 1; the pressure gauge 102 can be arranged at the top of the raw material tank 1 to detect the pressure in the raw material tank 1; the raw material tank powder filter 108 is used to prevent the material to be purified from being discharged from the raw material tank 1 with the movement of the inert gas.

[0060] The preheater 2 is provided with a preheater inert gas inlet 201, a preheater tail gas outlet 202, a preheater back-blowing gas inlet 203, a preheater feed port 204, a preheater discharge port 205, a heating device 206, a cyclone separator 207 and a gas distribution plate 208. The preheater inert gas inlet 201 is located at the bottom of the preheater and is used to introduce inert gas into the preheater 2 so that the material to be purified in the preheater is kept in a fluidized state to achieve a better preheating effect; the gas distribution plate 208 is located above the preheater inert gas inlet 201 and is used to evenly distribute the inert gas introduced from the preheater inert gas inlet 201 to better maintain the fluidized state of the material to be purified; the preheater back-blowing gas inlet 203 is used to introduce back-blowing gas into the preheater 2 so that the preheated material to be purified The material is transferred out of the preheater; the preheater feed port 204 is connected to the raw material tank discharge port 104 on the raw material tank 1, and is used to transport the material to be purified in the raw material tank 1 to the preheater 2. As an example, a preheater feed valve 209 can be provided between the raw material tank discharge port 104 and the preheater feed port 204, and the preheater discharge port 205 is used to output the preheated material to be purified out of the preheater 2; the heating device 206 can be provided on the side wall of the preheater 2, and is used to preheat the material to be purified in the preheater 2. The heating device 206 can specifically be an electric heating device; the cyclone separator 207 is located at the top of the preheater, and the gas outlet of the cyclone separator 207 is connected to the preheater tail gas outlet 203, and is used to retain most of the material to be purified in the preheater 2 and discharge the inert gas.

[0061] The high temperature furnace 3 is used to purify the material to be purified, and has a purification reaction chamber inside. The material to be purified undergoes a high temperature purification reaction in the purification reaction chamber, and the metal impurities are evaporated and removed by reaching the boiling point of the metal to produce high-purity carbon nanotube powder. Specifically, the high temperature furnace 3 is provided with a high temperature furnace feed port 301, a high temperature furnace discharge port 302, a high temperature furnace oxygen content monitor 303, and a temperature measuring device 304; the high temperature furnace feed port 301 is connected to the preheater discharge port 205 and is arranged at the top of the high temperature furnace 3, and is used to transport the preheated material to be purified from the preheater 2 to the high temperature furnace 3 and to introduce inert gas into the high temperature furnace 3; the high temperature furnace discharge port 302 is arranged at the top of the high temperature furnace 3, and is used to discharge the material purified by high temperature from the high temperature furnace 3; the high temperature furnace oxygen content monitor 303 can be arranged at the top of the high temperature furnace 3, and is used to monitor the oxygen content in the purification reaction chamber inside the high temperature furnace 3; the temperature measuring device 304 can be arranged at the top of the high temperature furnace 3, and is used to detect the temperature in the purification reaction chamber inside the high temperature furnace 3.

[0062] The impurity collecting tank 4 is used to collect impurities obtained by the purification reaction. The impurity collecting tank 4 is provided with an impurity collecting tank air inlet 401, a slag removal port 402, an impurity collecting tank tail gas outlet 403, an impurity collecting tank filter device 404, and a cooling jacket 405; the impurity collecting tank air inlet 401 can be set at the top of the impurity collecting tank 4, and is connected to the high-temperature furnace discharge port 302 of the high-temperature furnace 3, and is used to transport the metal impurity vapor generated in the high-temperature furnace 3 to the impurity collecting tank 4; the slag removal port 402 can be set at the bottom of the impurity collecting tank 4, and is used to discharge solid slag; the impurity collecting tank tail gas outlet 403 is used to discharge the waste gas from the impurity collecting tank; the impurity collecting tank filter device 404 is set at the impurity collecting tank tail gas outlet 403, and is used to filter the powder carried in the tail gas; the cooling jacket 405 can be set on the outer wall of the impurity collecting tank 4, and is used to cool the metal impurity vapor to obtain solid slag and tail gas. Furthermore, the air inlet 401 of the impurity collection tank and the discharge port 302 of the high-temperature furnace may be connected via an electric heating pipe 41 to ensure that the metal impurity vapor maintains a high temperature without being cooled in the pipe.

[0063] The powder separator 5 is used to separate the gas-solid mixture containing the purified material. The powder separator 5 is provided with a powder separator feed port 501, a powder outlet 502, a powder separator tail gas outlet 503, a powder separator back-blowing gas inlet 504, and a powder separator filtering device 505; the powder separator feed port 501 is connected to the high-temperature furnace discharge port 302, and is used to transport the gas-solid mixture containing the purified material to the powder separator 5; the powder outlet 502 can be arranged at the bottom of the powder separator, and is used to output the purified material after gas-solid separation from the powder separator 5; the powder separator back-blowing gas inlet 504 can be arranged at the top of the powder separator 5, and is used to pass back-blowing gas to transfer the purified material out of the powder separator; the powder separator tail gas outlet 503 can be arranged at the top of the powder separator, and is used to discharge the tail gas after gas-solid separation from the powder separator 5; the powder separator filtering device 505 is arranged at the powder separator tail gas outlet 503, and is used to filter the purified material. Further, the powder separator feed port 501, the high temperature furnace discharge port 302 and the impurity collection tank air inlet 401 can be connected through the first three-way valve 10, and a high temperature furnace outlet valve 40 is provided between the high temperature furnace discharge port 302 and the first three-way valve 10 to control whether to output materials from the high temperature furnace 3. Further, the powder separator feed port 501 and the high temperature furnace discharge port 302 can be connected through a cooling pipe 42 to cool the purified material after purification from the high temperature furnace 3 for subsequent product collection. As an example, the cooling pipe 42 can take the form of a jacket, and the circulating cooling liquid in the jacket is water or liquid nitrogen.

[0064] The product collecting tank 7 is used to collect purified materials, and is provided with a product collecting tank feed port 701 and a product collecting tank discharge port 702; the product collecting tank feed port 701 can be arranged at the upper part of the product collecting tank 7, and is connected with the powder outlet 502, so as to transport the purified materials after gas-solid separation to the product collecting tank 7 for storage; the product collecting tank discharge port 702 can be arranged at the bottom of the product collecting tank, so as to discharge the purified materials stored in the product collecting tank 7.

[0065] The actual working process of the above device is as follows:

[0066] (1) After the raw material tank 1 is loaded with the material to be purified, the raw material tank air inlet valve 83 and the raw material tank air outlet valve 80 are opened, and an inert gas is introduced into the raw material tank. At the same time, the multi-stage vacuum system 6 is continuously evacuated to perform a gas replacement operation on the raw material tank. The opening of the replacement gas outlet control valve 60 is controlled to be between 10% and 80%. The oxygen content in the raw material tank is detected to be lower than 0.01% to prevent oxidation damage to the material to be purified during the subsequent preheating or high-temperature purification process. After the replacement operation is completed, the raw material tank air inlet valve 83 and the raw material tank air outlet valve 80 are closed;

[0067] (2) opening the preheater feed valve 209, controlling the opening and closing of the electric discharge gate valve 103 and controlling the feed amount entering the preheater 2 at a time according to the numerical indication of the material level meter 105, maximizing and safely utilizing the volume of the high-temperature furnace reaction chamber; continuously introducing inert gas from the preheater inlet 201, and preheating the raw material to be purified to the preheating temperature in a fluidized form through the action of the gas distributor 208;

[0068] (3) The preheater backflush valve 84 is opened, and the inert backflush gas entering through the preheater backflush gas inlet 203 transports the preheated material to be purified through the preheater discharge port 205 and the second three-way valve 20 to the reaction chamber of the high-temperature furnace 3. Then, the electric discharge gate valve 103 is opened and the feed amount entering the preheater 2 at a single time is controlled to continue preheating the next batch of material to be purified.

[0069] (4) The temperature in the reaction chamber of the high-temperature furnace 3 is controlled within the process temperature range. During the high-temperature purification process, the high-temperature purification valve 85 is opened to allow the inert gas to be continuously input into the reaction chamber of the high-temperature furnace 3 through the second three-way valve 20 and to control the pressure in the reaction chamber of the high-temperature furnace 3 through the carrier gas pressure, so that the metal impurity vapor in the reaction chamber of the high-temperature furnace 3 is taken out. A single batch of materials to be purified stays in the reaction chamber of the high-temperature furnace 3 for a period of time to complete the purification; during the purification process, the tail gas is continuously introduced into the impurity collection tank 4 through the electric heating pipe 41 and the first three-way valve 10, and the metal impurity vapor is cooled to complete the collection, and the waste gas is discharged from the tail gas outlet 403 of the impurity collection tank; during the high-temperature purification process, the tail gas control valve 70 is controlled to open at 10%-80% to promote the collection of metal impurity vapor;

[0070] (5) After the residence time of a single batch of materials to be purified in the reaction chamber of the high-temperature furnace 3 meets the process requirements, the high-temperature furnace inlet valve 30 is closed to stop the introduction of the inert gas, and the vacuum degree of the vacuum gauge 29 is adjusted to a certain degree through the multi-stage vacuum system 6, so that the gas-solid mixture containing the purified materials after purification passes through the high-temperature furnace outlet valve 40 and the first three-way valve 10, and passes through the cooling pipe 42, and then is cooled to below 400° C. and then extracted and sent to the powder separator 5;

[0071] (6) The powder separator 5 settles the purified material to the bottom of the tank, and the clean exhaust gas is discharged after passing through the filter device 505 of the powder separator and the filter system of the multi-stage vacuum system 6; after the purified material is extracted from the high-temperature furnace reaction chamber, step (3) can be repeated to continue to purify the next batch of materials to be purified;

[0072] (7) The purified material after settling is back-flushed through the powder separator back-flushing gas inlet 504 at the top of the powder separator 5 to the product tank 7 for storage.

[0073] (8) This process is repeated to achieve continuous purification of the material to be purified.

[0074] The embodiments of the present application are described in detail below.

[0075] Example 1: A method for continuous high-temperature purification of carbon nanotubes using gas transport

[0076] (1) The density is 0.1 g / cm 3 After the purified raw material containing Fe multi-walled carbon nanotubes is loaded into the raw material tank 1 to 80% of the tank volume, the raw material tank air inlet valve 83 and the raw material tank air outlet valve 80 are opened, and the opening of the replacement gas outlet control valve 60 is controlled to be 30%. The system performs continuous vacuuming and argon replacement operations, and the oxygen content in the raw material tank 1 is detected to be lower than 0.01%. After the replacement operation is completed, the raw material tank air inlet valve 83 and the raw material tank air outlet valve 80 are closed;

[0077] (2) Open the preheater feed valve 209, control the opening and closing of the electric discharge gate valve 103, and control the feed amount entering the preheater 2 at a single time to be 5% of the tank volume according to the numerical indication of the tank level meter 105; close the electric discharge gate valve 103 and the preheater feed valve 209, and continue to introduce argon gas from the preheater inert gas inlet 201, and preheat the carbon nanotube purification raw material in a fluidized form through the action of the gas distributor 208, and control the temperature of the preheater 2 to 1200°C;

[0078] (3) The preheater back-blowing valve 84 is opened, and the argon gas entering through the preheater back-blowing gas inlet 203 transports the preheated purified carbon nanotube raw material through the preheater discharge port 205 and the second three-way valve 20 to the graphite reaction cavity 36 of the high-temperature furnace. Then, the preheater back-blowing valve 203 is closed, and the electric discharge gate valve 103 is opened to control the feed amount entering the preheater 2 at a single time, and the next batch of purified carbon nanotube raw materials is continued to be preheated;

[0079] (4) The temperature of the high-temperature furnace graphite reaction cavity 36 is controlled at 1900° C. During the high-temperature purification process, the high-temperature purification valve 85 is opened to allow argon to be continuously input through the second three-way valve 20 and the pressure in the cavity is controlled to be 0.12 MPa, so that the metal impurity vapor in the cavity is taken out. A single batch of carbon nanotube purification raw materials stays in the high-temperature furnace graphite reaction cavity 36 for 3 hours to complete the purification; during the purification process, the tail gas is continuously introduced into the impurity collection tank 4 through the electric heating pipe 41 and the first three-way valve 10, and the impurity vapor is cooled to complete the collection, and the waste gas is discharged from the tail gas outlet 403 of the impurity collection tank; during the high-temperature purification process, the tail gas control valve 70 is controlled to open at 20% to promote the collection of metal impurity vapor gas;

[0080] (5) After the residence time of a single batch of purified carbon nanotube raw materials in the graphite reaction cavity 36 of the high-temperature furnace meets the process requirements, the high-temperature furnace inlet valve 30 is closed to stop the introduction of argon gas, and all vacuum pumps of the multi-stage vacuum system 6 are opened to make the vacuum degree of the vacuum gauge 29 reach below 50 Pa, so that the purified carbon nanotube high-purity product passes through the high-temperature furnace outlet valve 40 and the first three-way valve 10, and passes through the cooling pipe 42, and then is cooled to below 400° C. and then extracted and sent to the powder separator 5;

[0081] (6) The powder separator 5 settles the high-purity carbon nanotube product to the bottom of the tank, and the clean exhaust gas is discharged after passing through the powder filter device 505 and the filtering system of the multi-stage vacuum system 6; after the high-purity carbon nanotube product is extracted from the high-temperature furnace reaction chamber, step (3) can be repeated to continue to purify the next batch of carbon nanotube purified raw materials;

[0082] (7) The high-purity carbon nanotube product after sedimentation is back-flushed into the product tank 7 for storage through the back-flushing gas inlet 504 at the top of the powder separator 5.

[0083] (8) This process is repeated to achieve continuous purification of crude carbon nanotubes.

[0084] Example 2: A method for continuous high-temperature purification of carbon nanotubes using gas transport

[0085] (1) The density is 0.12g / cm 3After the purified raw material containing Fe / Mo single-walled carbon nanotubes is loaded into the raw material tank 1 to 80% of the tank volume, the raw material tank air inlet valve 83 and the raw material tank air outlet valve 80 are opened, and the opening of the replacement gas outlet control valve 60 is controlled to be 40%. The system performs continuous vacuuming and argon replacement operations, and the oxygen content in the raw material tank 1 is detected to be lower than 0.01%. After the replacement operation is completed, the raw material tank air inlet valve 83 and the raw material tank air outlet valve 80 are closed;

[0086] (2) Open the preheater feed valve 209, control the opening and closing of the electric discharge gate valve 103, and control the feed amount entering the preheater 2 at a single time to be 6% of the tank volume according to the numerical indication of the tank level meter 105; close the electric discharge gate valve 103 and the preheater feed valve 209, and continue to introduce argon gas from the preheater inert gas inlet 201, and preheat the carbon nanotube purification raw material in a fluidized form through the action of the gas distributor 208, and control the temperature of the preheater 2 to 1300° C.;

[0087] (3) The preheater back-blowing valve 84 is opened, and the argon gas entering through the preheater back-blowing gas inlet 203 transports the preheated purified carbon nanotube raw material through the preheater discharge port 205 and the second three-way valve 20 to the graphite reaction cavity 36 of the high-temperature furnace. Then, the preheater back-blowing valve 203 is closed, and the electric discharge gate valve 103 is opened to control the feed amount entering the preheater 2 at a single time, and the next batch of purified carbon nanotube raw materials is continued to be preheated;

[0088] (4) The temperature of the high-temperature furnace graphite reaction chamber 36 is controlled at 1800° C. During the high-temperature purification process, the high-temperature purification valve 85 is opened to allow argon to be continuously input through the second three-way valve 20 and the pressure in the chamber is controlled to be 0.11 MPa, so that the metal impurity vapor in the chamber is taken out. A single batch of carbon nanotube purification raw materials stays in the high-temperature furnace graphite reaction chamber 36 for 2 hours to complete the purification; during the purification process, the tail gas is continuously introduced into the impurity collection tank 4 through the electric heating pipe 41 and the first three-way valve 10, and the impurity vapor is cooled to complete the collection, and the waste gas is discharged from the tail gas outlet 403 of the impurity collection tank; during the high-temperature purification process, the tail gas control valve 70 is controlled to open at 30% to promote the collection of metal impurity vapor gas;

[0089] (5) After the residence time of a single batch of purified carbon nanotube raw materials in the graphite reaction cavity 36 of the high-temperature furnace meets the process requirements, the high-temperature furnace inlet valve 30 is closed to stop the introduction of argon gas, and all vacuum pumps of the multi-stage vacuum system 6 are opened to make the vacuum degree of the vacuum gauge 29 reach below 30 Pa, so that the purified carbon nanotube high-purity product passes through the high-temperature furnace outlet valve 40 and the first three-way valve 10, and passes through the cooling pipe 42, and then is cooled to below 400° C. and then is extracted and sent to the powder separator 5;

[0090] (6) The powder separator 5 settles the high-purity carbon nanotube product to the bottom of the tank, and the clean exhaust gas is discharged after passing through the powder filter device 505 and the filtering system of the multi-stage vacuum system 6; after the high-purity carbon nanotube product is extracted from the high-temperature furnace reaction chamber, step (3) can be repeated to continue to purify the next batch of carbon nanotube purified raw materials;

[0091] (7) The high-purity carbon nanotube product after sedimentation is back-flushed into the product tank 7 for storage through the back-flushing gas inlet 504 at the top of the powder separator 5.

[0092] (8) This process is repeated to achieve continuous purification of crude carbon nanotubes.

[0093] Detection of metal impurity content in carbon nanotubes: ICP (Inductively coupled plasma spectrometry) was used to test the content of metal impurities such as Fe, Mg, and Ni in the raw carbon nanotubes to be purified and the carbon nanotubes purified in Example 1-2. The metal impurity content of the carbon nanotubes was measured, and the average value can be obtained by multiple tests. The test results are shown in Table 1.

[0094] Purity test of carbon nanotubes: calcination in a muffle furnace at a high temperature of 950°C for 2 hours is used for ash content test. Multiple tests can be performed to obtain an average value. The test results are shown in Table 1.

[0095] Table 1: Comparison of purity and metal impurity content of carbon nanotubes to be purified and purified carbon nanotubes

[0096]

[0097] The above test results show that the metal impurity content in the carbon nanotubes purified by the device of the present application is significantly reduced, and the purification effect on the carbon nanotubes is better. Moreover, the device can purify continuously and is suitable for large-scale production.

[0098] In the description of the present application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present application, "plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0099] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0100] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0101] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0102] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A device for high temperature purification of carbon nanotubes, characterized in that: include: An inert gas delivery pipe, used for providing inert gas; A preheater, the top of which is connected to the inert gas delivery pipe and is used to preheat the material to be purified; A high temperature furnace, connected to the inert gas delivery pipe and the preheater, for high temperature purification of the preheated material to be purified; An impurity collection tank, connected to the high-temperature furnace, for collecting metal impurities; A powder separator, connected to the high-temperature furnace, for separating and purifying materials; a multi-stage vacuum system connected to the impurity collection tank and the powder separator, and used to provide driving force for the transfer of the metal impurities from the high-temperature furnace to the impurity collection tank and the transfer of the purified material from the high-temperature furnace to the powder separator; An exhaust gas discharge pipe is connected to the preheater, the impurity collection tank and the multi-stage vacuum system and is used to discharge the exhaust gas.

2. The device according to claim 1, characterized in that It also includes a raw material tank, on which is provided: an inert gas inlet of the raw material tank, connected to the inert gas delivery pipe, and used for inputting inert gas into the raw material tank; A raw material tank inert gas outlet, used to discharge the inert gas from the raw material tank; A raw material tank feed port, used to input the material to be purified into the raw material tank; A material outlet of the raw material tank, used to output the material to be purified from the raw material tank; A material level meter, used to detect the storage amount of the material to be purified in the raw material tank; A raw material tank oxygen content monitor, used to monitor the oxygen content in the raw material tank; The raw material tank powder filtering device is arranged at the inert gas outlet of the raw material tank and is used to filter the material to be purified.

3. The device according to claim 2, characterized in that The multi-stage vacuum system is connected to the raw material tank, and a replacement gas outlet control valve is arranged between the multi-stage vacuum system and the raw material tank.

4. The device according to claim 1, characterized in that The preheater is provided with: a preheater inert gas inlet, located at the bottom of the preheater and connected to the inert gas delivery pipe, for introducing the inert gas into the preheater; A preheater tail gas outlet, located at the top of the preheater, for discharging the tail gas in the preheater; A preheater backwash gas inlet, located at the top of the preheater, for introducing backwash gas into the preheater; A preheater feed port, used for conveying the material to be purified into the preheater; A preheater discharge port, used to discharge the preheated material to be purified out of the preheater; A heating device, located on the side wall of the preheater, used for preheating the material to be purified; A cyclone separator, located at the top of the preheater and connected to the tail gas outlet of the preheater, for separating the material to be purified from the inert gas; A gas distribution plate is located between the inert gas inlet of the preheater and the heating device, and is used to distribute the inert gas to fluidize the material to be purified.

5. The device according to claim 1, characterized in that The high temperature furnace comprises, from inside to outside, a graphite reaction chamber wall, a heat-insulating layer, a heating device, a heat-resistant lining and a circulating cooling water jacket, wherein the graphite reaction chamber wall defines a purification reaction chamber.

6. The device according to claim 1, characterized in that The high temperature furnace is provided with: A high temperature furnace feed port, located at the top of the high temperature furnace and connected to the preheater discharge port, for conveying the preheated material to be purified to the high temperature furnace; A high temperature furnace discharge port, located at the top of the high temperature furnace, for discharging the metal impurities and the purified material out of the high temperature furnace; A high temperature furnace oxygen content monitor, located at the top of the high temperature furnace, for detecting the oxygen content in the high temperature furnace; The temperature measuring device is used to detect the temperature in the high temperature furnace.

7. The device according to claim 1, characterized in that The impurity collection tank is provided with: An air inlet of the impurity collection tank is located at the top of the impurity collection tank and is connected to the discharge port of the high-temperature furnace, and is used to transport metal impurity vapor to the impurity collection tank; A slag removal port, located at the bottom of the impurity collection tank, for discharging impurity slag from the impurity collection tank; An impurity collection tank tail gas outlet, used to discharge tail gas from the impurity collection tank; An impurity collection tank filtering device, located at the tail gas outlet of the impurity collection tank, is used to filter the impurity slag; A cooling jacket is located on the outer side wall of the impurity collecting tank and is used for cooling the metal impurity vapor.

8. The device according to claim 1, characterized in that The discharge port of the preheater, the inert gas delivery pipe and the feed port of the high-temperature furnace are connected via a second three-way valve; and / or The discharge port of the high temperature furnace, the feed port of the impurity collection tank and the feed port of the powder separator are connected through a first three-way valve.

9. The device according to claim 1, characterized in that The impurity collection tank and the high-temperature furnace are connected via an electric heating pipeline.

10. The device according to claim 1, characterized in that An exhaust gas control valve is provided between the impurity collection tank and the multi-stage vacuum system.

11. The device according to claim 1, characterized in that The powder separator is provided with: A powder separator feed port, located at the upper portion of the powder separator, communicated with the discharge port of the high-temperature furnace, and used for conveying the gas-solid mixture containing the purified material into the powder separator; A powder separator discharge port, located at the bottom of the powder separator, for discharging the purified material out of the powder separator; A powder separator tail gas outlet, located at the top of the powder separator, for discharging the tail gas in the powder separator; A back-flushing gas inlet for the powder separator is located at the top of the powder separator and is connected to the inert gas delivery pipe, and is used to introduce back-flushing gas into the powder separator; The powder separator filtering device is located at the tail gas outlet of the powder separator and is used for filtering the purified material.

12. The device according to claim 1, characterized in that The powder separator and the high-temperature furnace are communicated with each other through a cooling pipe.

13. The device according to claim 2, characterized in that The multi-stage vacuum system includes 3-5 stages of vacuum pumps.

14. The device according to claim 13, characterized in that The inert gas delivery pipe comprises a main pipe and a first branch pipe, a second branch pipe, a third branch pipe, and a fourth branch pipe connected to the main pipe; The first branch pipe is connected to the raw material tank and the bottom of the preheater, and the first branch pipe is provided with a preheater air inlet valve and a raw material tank air inlet valve; The second branch pipe is connected to the top of the preheater, and a preheater back-blowing valve is provided on the second branch pipe; The third branch pipe is connected to the high temperature furnace, and a high temperature purification valve is provided on the third branch pipe; The fourth branch pipe is communicated with the powder separator, and a powder separator back-blowing valve is arranged on the fourth branch pipe.

15. The device according to claim 1, characterized in that It also includes a product collection tank, which is connected to the powder separator and is used to collect the purified material.

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