Vertical graphite purification furnace and graphite purification method

Abstract

The invention provides a vertical graphite purification furnace and a graphite purification method.The vertical graphite purification furnace comprises a feeding pipe, a heating pipe, a barrel, a protective sleeve, a first material conveying mechanism and an exhaust mechanism, the feeding pipe, the heating pipe, the protective sleeve and the barrel are sequentially sleeved from inside to outside, and intervals are formed between the feeding pipe, the heating pipe, the protective sleeve and the barrel; the lower end of the feeding pipe is connected with the first material conveying mechanism, the upper end of the feeding pipe is provided with a discharging port, an exhaust cavity is reserved between the discharging port and the top of the heating pipe, and the exhaust cavity is communicated with the exhaust mechanism. According to the device, impurity substances can be easily volatilized or converted into a gas state, so that impurity gas is exhausted through the exhaust mechanism, a graphite material with higher purity is obtained, and the exhaust cavity between the top end of the feeding pipe and the top end of the heating pipe is beneficial to fluffy graphite, so that volatilization of gas impurities is very facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of graphite purification, and particularly relates to a vertical graphite purification furnace and a graphite purification method. Background Art

[0002] Graphite purification refers to the treatment and processing of raw graphite materials to remove impurities and impure substances therein, thereby improving the purity and quality of the graphite materials. Generally, the graphite purification process includes:

[0003] Preliminary treatment: First, the raw graphite materials (such as natural graphite) are crushed and ground into appropriate particle sizes, which helps to improve the efficiency of subsequent treatment processes.

[0004] Pickling: The ground graphite particles are immersed in an acidic solution, such as concentrated sulfuric acid (H2SO4). The pickling process can remove impurities such as basic oxides, organic substances, and organic acids on the surface of the graphite.

[0005] Alkaline washing: The pickled graphite particles are washed and immersed in an alkaline solution, such as sodium hydroxide (NaOH) solution. Alkaline washing can remove the acidic impurities and acidic oxygen-containing substances remaining during the pickling process.

[0006] Heat treatment: The alkaline-washed graphite particles are subjected to high-temperature treatment, which can help remove the remaining organic substances and impurities and further improve the purity of the graphite. The heat treatment temperature and time are adjusted according to the material quality requirements.

[0007] Fine treatment: In some cases, some more refined treatment steps can be carried out to further purify the graphite materials, which may include physical treatment, chemical treatment, or other specific treatment methods, depending on specific requirements and applications.

[0008] At present, high-temperature heat treatment is usually used for fine purification of graphite. Removing impurities in graphite is a key means of graphite treatment and purification. The following equipment is mainly used in the current technology for graphite purification: 1. Acheson furnace. The working principle of the Acheson furnace is to closely arrange graphite crucibles filled with materials to be treated in a rectangular foundation pit, and fill conductive heat-insulating materials in the gaps. Due to various factors such as cost control, material conductivity, and hardness, coke is usually used as the gap filling material. Coke has many impurities and will generate a large amount of impurity gases during the heating process, which not only causes environmental pollution but also contaminates the materials to be treated. 2. Carbon tube furnace. The length of the carbon tube furnace is short, usually 5 meters, and the longest does not exceed 10 meters. The cavity is also the smallest, and the diameter of the heating cavity usually does not exceed 30 cm. Since the carbon material is directly electrically heated, the theoretical maximum temperature can reach 3000 °C, and the actual production process is usually ≥2600 °C, which meets the purification requirements of high-purity natural graphite. Therefore, carbon tube furnaces are commonly used in industry for graphite purification. For example, patent CN110260657A is a relatively common graphite purification furnace in the existing technology.

[0009] In the existing technology, when using a carbon tube furnace for purification, there are mainly horizontal carbon tube furnaces and vertical carbon tube furnaces. When the horizontal carbon tube furnace is used for heating and purifying graphite, it generally needs to be used in combination with a graphite round boat, which increases the labor cost of the processes of loading and unloading the boat and the material cost of the graphite round boat as a consumable part. At the same time, the graphite round boat is heated and cooled synchronously with the raw material graphite, and is heated ineffectively in the furnace body, resulting in serious energy waste; in addition, the heavy load on the heating tube of the horizontal furnace greatly reduces the service life of the heating tube, and the heating tube is prone to fouling, which not only hinders the operation of pushing the boat but also causes losses to the heating tube and the boat; it is a common defect of the furnaces of patent CN110260657A that impurities are not easy to remove.

[0010] Since the vertical carbon tube furnace has good passing performance, can make full use of the reaction space, and does not require the use of a graphite round boat, it has obvious advantages, such as the vertical carbon tube furnace of patent CN114514196A. The main defect in the use of this patent is that: due to the upward feeding and downward discharging of materials, the materials are prone to accumulate when descending in the high-temperature pipeline, resulting in the inability to effectively discharge impurity gases, and then causing problems of impurity removal obstacles. Summary of the Invention

[0011] This application proposes a vertical graphite purification furnace and a graphite purification method, which solve the technical problems that in the existing problems, the vertical carbon tube furnace cannot effectively discharge impurity gases when purifying graphite, thus affecting the graphite purification effect.

[0012] The technical solution adopted by the invention is: a vertical graphite purification furnace, which includes a feed pipe, a heating pipe, a cylinder body, a protective sleeve, a first material conveying mechanism and an exhaust mechanism. The feed pipe, the heating pipe, the protective sleeve and the cylinder body are sleeved in sequence from the inside to the outside and have intervals between them. The lower end of the feed pipe is connected to the first material conveying mechanism. The upper end of the feed pipe is a discharge port, and the horizontal height of the discharge port is lower than the top of the heating pipe. The space between the discharge port and the top inside the heating pipe serves as an exhaust cavity, and the exhaust cavity is communicated with the exhaust mechanism.

[0013] Further, the vertical graphite purification furnace further includes a cooling pipe. The cooling pipe is connected to the lower end of the heating pipe. The feed pipe passes through the bottom end of the cooling pipe and is connected to the first material conveying mechanism. The bottom of the cooling pipe is the discharge port.

[0014] Further, installation ports are respectively provided at the upper and lower ends of the cylinder body. A tapered sleeve is provided in the installation port, and the upper and lower ends of the heating pipe are respectively arranged inside the tapered sleeve. A sealing and heat-insulating sleeve is further provided between the tapered sleeve and the installation port. Power connection modules for connecting to the power supply of the heating pipe are further provided on the outer sides of the upper and lower tapered sleeves, and an insulating layer is provided on the surface of the power connection module.

[0015] Further, the upper and lower ends of the protective sleeve abut against the tapered sleeve, and an insulating ceramic is provided between the protective sleeve and the tapered sleeve.

[0016] Further, there is a cavity between the protective sleeve and the heating pipe, and the cavity is filled with an inert protective gas; a heat-insulating cavity is provided between the protective sleeve and the cylinder body, and the heat-insulating cavity is filled with a heat-insulating material. The protective sleeve allows the inert protective gas to penetrate.

[0017] Further, cooling water jackets are further provided on the surface of the cylinder body and the surface of the power connection module. A cooling water circulation channel is provided inside the cooling water jacket. A cooling water circulation channel is provided outside the cooling pipe. The lower end of the cooling pipe is further communicated with a transition pipe. The lower end of the transition pipe is communicated with an aggregate tank. A base is provided at the lower end of the aggregate tank. A valve is further provided on the transition pipe. A second material conveying mechanism is further provided between the transition pipe and the aggregate tank. The second material conveying mechanism is used to convey graphite downward or horizontally into the aggregate tank.

[0018] Further, the exhaust mechanism includes an air extraction pipe, an air extraction device and a dredging device. One end of the air extraction pipe is communicated with the exhaust cavity, and the other end is communicated to the outside of the cylinder body and is connected to the air extraction device and the dredging device; and there is a filter element in the air extraction pipe. The filter element is used to adsorb impurities volatilized at high temperature, and the filter element is made of a high-temperature resistant material.

[0019] Further, the first material conveying mechanism includes a feeding channel, a screw rod, a first driving motor, and an automatic feeding tank. The feeding channel is communicated with the lower part of the feeding pipe. The screw rod is arranged in the feeding channel. The first driving motor is in transmission connection with the screw rod. The automatic feeding tank is used for injecting graphite into the feeding channel.

[0020] Further, the automatic feeding tank includes a feeding hopper, a feeding trough, a transfer trough, and a material conveying trough. The lowest horizontal position of the feeding hopper is internally connected to the feeding pipe. The material conveying trough is arranged at the highest horizontal position of the feeding hopper. The transfer trough is connected to the upper end of the material conveying trough. The feeding trough is connected to the upper end of the transfer trough. Switch valves are arranged on the communication channels between the transfer trough and the material conveying trough, and between the transfer trough and the feeding trough. The transfer trough is provided with an air extraction port and an inert gas filling port, and preheating coils are arranged on the inner side of the feeding trough and / or the transfer trough and / or the material conveying trough.

[0021] A graphite purification method for a vertical graphite purification furnace, the graphite purification method comprising: Step S1, performing material pretreatment, evacuating the material to be purified in the automatic feeding tank and then filling it with an inert gas to replace the air in the material to be purified with the inert gas, and preheating the material; Step S2, conveying the material to be purified to the heating pipe for high-temperature purification, and exchanging heat between the material to be purified and the refined material after high-temperature purification, so that the material to be purified continues to be preheated; Step S3, obtaining the refined material after high-temperature purification by the heating pipe, exchanging heat between the refined material output by the heating pipe and the material to be purified before being conveyed to the heating pipe, and physically cooling the refined material; Step S4, collecting the cooled refined material.

[0022] The beneficial effects of the present invention are as follows: When the graphite material is in the feeding pipe (in the middle of the heating pipe) and when the graphite material leaves the feeding pipe and enters the annular space formed by the heating pipe and the feeding pipe, it is in the high-temperature heating and purification stage. During the heating process, the high-temperature environment helps to volatilize or transform the impurity substances into a gaseous state, thereby achieving degradation and separation. The impurity gas is discharged by the air extraction device, so as to obtain a graphite material with higher purity. The exhaust cavity between the top end of the feeding pipe and the top end of the heating pipe helps the graphite to be fluffy, that is, when the graphite material enters the inner annular space of the heating pipe from the outlet at the top end of the feeding pipe, due to the sudden increase in space, it appears in a fluffy and diffused state, which is very conducive to the volatilization of gas impurities; The graphite material after heating and purification moves downward from the inner annular space of the heating pipe. When the graphite material leaves the heating pipe and falls into the cooling pipe, it is in the process of cooling down, so as to facilitate the collection of the purified refined graphite material. Description of the Drawings

[0023] Figure 1 It is a schematic diagram of the overall structure of the vertical graphite purification furnace in the first embodiment;

[0024] Figure 2 It is a schematic diagram of the overall structure of a vertical graphite purification furnace in a second embodiment;

[0025] Figure 3 It is a schematic diagram of the overall structure of the vertical graphite purification furnace in the third embodiment.

[0026] The figures are as follows:

[0027] 1. Top plate; 2. Laser distance measuring hole; 3. Temperature measuring hole; 4. Cooling water jacket; 5. Cylinder; 6. End cover; 7. Cooling water ring; 8. Insulation ring; 8.1. Sealing insulation sleeve; 9. Cone sleeve; 10. Insulation layer; 11. Power connection module; 12. Heating pipe; 13. Cooling pipe; 14. Turbine transition pipe; 14.1. Discharging bin; 15. Bearing seat; 16. Second material conveying mechanism; 17. Collecting trough; 18. Base; 19. First drive motor; 20. Spiral bearing seat; 21. Feed pipe; 22. Air inlet; 22.6, exhaust port; 23, first screw rod; 23.2, second screw rod; 24, feed trough; 24.1, feed hopper; 25, transfer trough; 26 (26.1), switch valve; 27, feed trough; 28, exhaust cavity; 29, exhaust pipe; 30, exhaust device; 31, dredging device; 32, protective sleeve; 33, feeding channel; 34, preheating coil; 35, air cavity; 36, insulation cavity; 37, discharge pipe; 38, exhaust port; 39, induction heater; 40, annular space;

[0028] In addition: 22.1, 22.2, 22.3, 22.4, and 22.5 are all air intakes. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0030] The present application discloses a vertical graphite purification furnace, such as Figure 1As shown, in the first embodiment, the furnace body of the vertical graphite purification furnace includes a cylinder body 5, heating tubes 12, cooling tubes 13, a feed pipe 21, a first material conveying mechanism, a second material conveying mechanism 16, and an exhaust mechanism. The heating tubes 12 are the core components of the vertical graphite purification furnace and are usually made of high-temperature heat-resistant materials such as graphite. The heating tubes 12 are vertically arranged inside the furnace body and provide heat energy through resistance heating. In Embodiment 1, the heating tubes 12 adopt the form of electric heating. By controlling the current and voltage of the power supply, the heating power and temperature of the heating tubes 12 can be adjusted. A protective sleeve 32 is also provided outside the heating tubes 12. The feed pipe 21, the heating tubes 12, the protective sleeve 32, and the cylinder body 5 are sleeved from the inside to the outside in sequence and have intervals between them. The lower end of the feed pipe 21 is connected to the first material conveying mechanism, and the upper end of the feed pipe 21 is a discharge port. The discharge port and the upper space of the heating tubes 12 form an exhaust cavity 28, and the exhaust cavity 28 is connected to the exhaust mechanism. The heating tubes 12 and the feed pipe 21 form an annular space 40.

[0031] The cooling tubes 13 are connected to the lower ends of the heating tubes 12 and are located below the heating tubes 12. The feed pipe 21 passes through the bottom end of the cooling tubes 13 and is connected to the first material conveying mechanism. The bottom of the cooling tubes 13 is the discharge port. The cooling tubes 13 are usually made of metal materials such as stainless steel to better conduct heat. The cooling tubes 13 are cooled by a cooling medium (such as water or coolant) flowing through, thereby cooling the graphite material inside the cooling tubes 13. The feed pipe 21 is vertically arranged, and the feed pipe 21 is located inside the heating tubes 12 and the cooling tubes 13. The feed pipe 21 is usually made of high-temperature resistant materials such as graphite. The first material conveying mechanism 19 conveys the graphite material to be purified into the furnace through the bottom feeding channel 33 and the feed pipe 21 to ensure that the graphite material can smoothly enter the furnace.

[0032] When using a vertical graphite purification furnace, first, the graphite material to be purified is conveyed into the vertical graphite purification furnace through the first material conveying mechanism. During the conveying process, the graphite material is conveyed upward in the feed pipe 21 from bottom to top. When the graphite material moves upward until it enters the annular space 40 above the feed pipe 21, the current and voltage of the heating pipe 12 are controlled to heat it and provide heat energy to heat the graphite material in the annular space 40 inside the heating pipe 12. When the graphite material is in the upper part of the feed pipe 21 (located in the heating pipe 12) and when the graphite material leaves the feed pipe 21 and enters the annular space 40 inside the heating pipe 12, it is in the high-temperature heating and purification stage. During the heating process, the high temperature helps to volatilize or transform the impurity substances into a gaseous state, thereby achieving degradation and separation. The impurity gases are discharged, and thus a graphite material with higher purity is obtained. The exhaust cavity 28 at the top of the feed pipe 21 and the upper space of the heating pipe 12 helps the graphite to fluff up. That is, when the graphite material enters the annular space 40 inside the heating pipe 12 from the outlet at the top of the feed pipe 21, it appears in a fluffy and diffused state due to the sudden increase in space, which is very conducive to the volatilization of gas impurities. The graphite material after heating and purification moves downward from the annular space between the heating pipe 12 and the feed pipe 21. When the graphite material leaves the annular space 40 between the heating pipe 12 and the feed pipe 21 and falls into the cooling pipe 13, it is cooled down to facilitate the collection of the purified fine graphite material.

[0033] Since the feed pipe 21 conveys the graphite material to be purified from bottom to top, while the graphite material that has been purified at high temperature in the above-mentioned annular space 40 moves downward. The temperature of the graphite material to be purified is relatively low, while the purified graphite material has just been heated by the heating pipe 12 and has a relatively high temperature. Therefore, the graphite material to be purified inside and outside the feed pipe 21 and the purified graphite material will conduct heat exchange. On the one hand, the graphite material to be purified is preheated before entering the annular space 40 inside the heating pipe 12. Through preheating, the graphite material can gradually reach the required temperature, which helps to form a stable high-temperature zone in the lower region of the exhaust cavity 28 and improve the utilization rate of heat energy. On the other hand, it can also cool down the fine graphite material in the annular space 40 after purification through heat exchange, improving the heat dissipation and cooling efficiency of the fine graphite material. And the cooling pipe 13 continues to cool the fine graphite material, which further increases the cooling area and uniformity of the fine graphite, ensuring rapid and uniform cooling of the fine graphite material. In summary, this application can achieve good effects in energy utilization, purification of the graphite material to be purified, and cooling of the purified graphite material.

[0034] Further, in the embodiments of the present invention, a top plate 1 is provided at the top of the exhaust cavity 28 of the heating tube 12 of the vertical graphite purification furnace. An air inlet 22.3 is provided on the top plate 1, and the air inlet is used to fill inert gas into the heating tube 12. Similarly, a lower air inlet 22.1 allows positive-pressure inert gas to rise from the graphite and converge into the exhaust cavity 28; two air inlets 22.2 allow positive-pressure inert gas to rise and fall in the air cavity 35 and converge into the exhaust cavity 28; the exhaust cavity 28 communicates with the air cavity 35 and is connected to an exhaust mechanism; the exhaust mechanism includes an exhaust pipe 29 (with a filter element inside, and the filter element is made of high-temperature resistant material), an air extraction device 30, and a dredging device 31. One end of the exhaust pipe 29 communicates with the exhaust cavity 28 and the air cavity 35, and the other end communicates to the outside of the cylinder body 5 and is connected to the air extraction device 30 and the dredging device 31. The air extraction device 30 forms a negative pressure to continuously extract gas impurities. The dredging device 31 includes a manual exhaust dredging rod, an air gun, etc., and can remove blocking substances by methods such as replacing the filter element or mechanical descaling to help restore smooth exhaust. Generally speaking, the exhaust mechanism can realize the discharge of internal gas impurities, which is beneficial to the purification process of graphite materials.

[0035] In addition, the cylinder body 5 surrounds the protective sleeve 32 to form a heat preservation cavity 36, which is filled with heat preservation materials (such as carbon black). The heating tube 12 and the protective sleeve 32 form an air cavity 35. Inert gas is filled into the heat preservation cavity 36 through the air inlet 22.5. The inert gas in the air cavity 35 will also penetrate through the protective sleeve 32 into the heat preservation cavity 36 under high-temperature conditions, thereby playing a protective role for the heat preservation materials to prevent the heat preservation materials from oxidizing. The inert gas can be discharged through the exhaust port 22.6 at the upper end of the cylinder body 5.

[0036] Installation ports are provided at both the upper and lower ends of the cylinder body 5, and a tapered sleeve 9 is provided inside the installation ports. The two ends of the heating tube 12 are respectively arranged inside the tapered sleeve 9, and an insulating ring 8 is also provided between the tapered sleeve 9 and the protective sleeve 32.

[0037] This design helps to reduce heat dissipation and improve the heat energy utilization efficiency. It can effectively prevent heat energy leakage and the entry of external air. Through effective sealing and heat insulation, the temperature inside the furnace can be stably controlled, energy waste can be reduced, and the purification effect of graphite can be improved.

[0038] In addition, a power connection module 11 with electrical connection is provided on the outer side of the tapered sleeve 9. An insulating layer 10 is provided on the end face of the power connection module 11. A cooling water jacket 4 is also provided on the surface of the cylinder body 5 and the surface of the power connection module 11. A cooling water circulation channel is provided inside the cooling water jacket 4. Through circulating cooling water, the cylinder body 5 and the power connection module 11 can be effectively cooled, the temperature of the power connection module 11 can be controlled, overheating and damage can be prevented, and at the same time, the cooling efficiency of the graphite material can be improved.

[0039] In summary, the above design can effectively reduce heat loss, improve the heat utilization efficiency, stably control the temperature inside the furnace, enhance the purification effect of graphite, prevent heat leakage and the entry of external air, reduce energy waste, effectively control the emission of internal gases and the isolation from external air, which is beneficial to the purification process of graphite materials. The application of the cooling water jacket 4 realizes the cooling of the furnace body and the power connection module 11, prevents overheating and damage, and improves the cooling efficiency of temperature reduction.

[0040] Furthermore, the upper and lower ends of the protective sleeve 32 are abutted against the tapered sleeve 9. The insulating ring 8 is used to isolate between the tapered sleeve 9 and the protective sleeve 32. Using insulating ceramics for the insulating ring 8 can effectively ensure electrical insulation between the protective sleeve 32, the tapered sleeve 9 and the heating tube 12. The protective sleeve 32 can provide a good supporting effect, avoiding the direct contact between the heating tube 12 and the heat-insulating material in the cavity 36, which can reduce the high-temperature penetration of impurities in the heat-insulating material into the heating tube 12 to contaminate the purified graphite. At the same time, an air cavity 35 is formed between the protective sleeve 32 and the heating tube 12. Passing inert gas through the air cavity 35 can effectively protect the protective sleeve 32 and the heating tube 12 from being oxidized by the adsorbed oxygen of the heat-insulating material and eroded by the penetrated impurities. In addition, the air cavity 35 is connected to the exhaust pipe 29 to timely extract the penetrated impurities, ensuring the quality of the purified graphite.

[0041] Furthermore, a cooling water circulation channel is also provided on the outer side of the cooling tube 13 to reduce the temperature of the cooling tube 13 through circulating cooling water to ensure the cooling effect. A turbine transition pipe 14 is connected to the lower end of the cooling tube 13, and the lower end of the turbine transition pipe 14 is further connected to the aggregate tank 17. The turbine transition pipe 14 serves to guide the graphite material from the cooling tube 13 to the aggregate tank 17, ensuring the smooth collection and transportation of the purified fine graphite material. At the same time, a bearing 15 is provided on the turbine transition pipe 14 for fixing the turbine. A second material conveying mechanism 16 is also provided between the turbine transition pipe 14 and the aggregate tank 17. The second material conveying mechanism 16 is used to convey the graphite material downward into the aggregate tank 17. The second material conveying mechanism 16 can continuously feed the graphite material in the turbine transition pipe 14 into the aggregate tank 17, avoiding the blockage of the turbine transition pipe 14 and ensuring the smooth collection of materials.

[0042] Furthermore, the first material conveying mechanism includes a feeding channel 33, a first driving motor 19, a first screw rod 23.2 and an automatic feeding tank. The feeding channel 33 is communicated with the lower end of the feeding pipe 21. The first driving motor 19 is in transmission connection with the lower first screw rod 23.2 to convey the material from the automatic feeding tank into the vertical graphite purification furnace. The automatic feeding tank is communicated with the feeding pipe 21 and is used for storing and supplying the graphite material to be purified.

[0043] According to the above additional features, the vertical graphite purification furnace can ensure the smooth output of materials by program - controlling the motor of the second material conveying mechanism 16, and ensure the smooth input of materials by program - controlling the motor of the first material conveying mechanism 9. Both the output and the input are controlled by the program, and the control signal is derived from the laser altimetry signal, so that the material balance in the furnace can be well controlled.

[0044] The automatic feeding trough consists of three parts: the upper feeding trough 27, the middle transfer trough 25, the lower material conveying trough 24 and the feeding hopper 24.1. The feeding hopper 24.1 is an inclined channel connecting the material conveying trough 24 and the feeding pipe 21. The lowest horizontal position of it is connected to the inside of the feeding pipe 21. Through the inclined feeding hopper 24.1, materials can flow downward by gravity. The material conveying trough 24 is located at the highest end of the feeding hopper 24.1, and the transfer trough 25 is located between the feeding trough 27 and the material conveying trough 24, playing a role in transition and controlling the material flow. Switch valves 26.1 and 26 are respectively provided on the communication channels between the transfer trough 25 and the material conveying trough 24 and the feeding trough 27 for controlling the material flow; An air extraction port 38 and an air inlet 22.4 (for introducing inert gas) are provided on the transfer trough 25, and a pre - heating coil 34 is provided inside the transfer trough 25 for pre - treating the graphite to be purified in the transfer trough 25, replacing the adsorbed water and air of the graphite material with inert gas to prevent water and oxygen from entering the high - temperature space to corrode the material conveying pipe and the heating pipe.

[0045] The specific working mode of the first material conveying mechanism is as follows: Through the combination of the first driving motor 19 and the first screw rod 23.2, the continuous conveying of graphite materials into the vertical graphite purification furnace is realized, which can improve production efficiency, reduce the workload and time consumption of manual operation. The structural design in the automatic feeding trough enables the materials to move and flow smoothly. Through the combination of the inclined feeding hopper 24.1, the transfer trough 25 and the feeding trough 24, it is ensured that the materials can be smoothly conveyed into the feeding pipe 21 of the vertical graphite purification furnace during the conveying process. The settings of the switching valves 26 and 26.1 allow controlling the flow of materials between the transfer trough 25 and the feeding trough 27, and between the transfer trough 25 and the feeding trough 24, which can be opened or closed when needed to achieve the control and regulation of the material flow. During the feeding process, the raw material graphite to be purified is added to the feeding trough 27. The switching valve 26.1 between the transfer trough 25 and the feeding trough 24 is closed, and the switching valve 26 between the transfer trough 25 and the feeding trough 27 is opened, so that the raw material graphite enters the transfer trough 25. After the feeding is completed, the switching valve 26 between the transfer trough 25 and the feeding trough 27 is closed. The air extraction port evacuates the transfer trough 25 to a relatively high vacuum degree, and then inert gas is supplemented through the inert gas filling port 22.4 to slightly higher than the atmospheric pressure. After the inert gas is introduced, the switching valve 26.1 between the transfer trough 25 and the feeding trough 24 is opened, so that the raw material graphite enters the feeding trough 24 and enters the feeding hopper 24.1; and the raw material graphite is preheated in advance by the preheating coil 38 in the feeding trough 27 and / or the transfer trough 25 and / or the feeding trough 24, so as to replace the adsorbed water and oxygen in the graphite material. It is conveyed upward through the first screw rod 23.2 to the feeding pipe 21, and the part higher than the feeding pipe 21 is heated and purified through the inner annular space 40 of the heating pipe 12, cooled by the cooling pipe 13, and cooled down through the turbine transition pipe 14 in sequence. The finished product after purification falls into the aggregate trough 17 for collection through the control of the bearing 15 and the turbine transition pipe 14.

[0046] The second material conveying mechanism 16 includes an inner turbine discharging system and a gear transmission system. By rotating the inner turbine, the transmission and control of materials are realized. Power is provided by a variable-frequency motor, and the rotation speed of the variable-frequency motor is controlled by the signal of the height measurement module. When the graphite level in its exhaust cavity 28 is high, the turbine rotation speed of the conveying mechanism 16 is accelerated, and when the graphite level in its exhaust cavity 28 is low, the turbine rotation speed of the conveying mechanism 16 is reduced; further, the same is true for the second material conveying mechanism 19. Furthermore, through the program system, the graphite level in the exhaust cavity 28 can be efficiently, accurately and reliably controlled, that is, the balance of the feeding and discharging material flow rates.

[0047] Specifically, the specific structure of the vertical graphite purification furnace is as follows: The top of the equipment is a top plate 1, on which a laser ranging hole 2, a temperature measuring hole 3 and an air inlet are integrated. Circular end caps 6 are provided at both the upper and lower ends of the cylinder body 5. There is a cooling water ring 7 outside the end cap 6. There is a small circular ring extending inward at the inner circle of the center of the end cap 6. The extension is fixed with a cone sleeve 9 through a sealing and heat insulation sleeve 8.1. An insulating layer 10 is provided between the cone sleeve 9 and the top plate 1 for isolation. A power connection module 11 is sleeved outside the cone sleeve 9. A protective sleeve 32 and a heating tube 12 are clamped between the cone sleeves 9 at both ends of the furnace body, and an insulating ring 8 is provided between the cone sleeve 9 and the protective sleeve 32; the lower cone sleeve is connected to a cooling tube 13 through an insulating pad. There is a cooling water jacket 4 outside the cooling tube 13. The lower inner side of the cooling tube 13 is connected to a turbine transition tube 14. A second driving motor is provided outside the bearing 15. Below the turbine transition tube 14 is an aggregate tank 17. The aggregate tank 17 is located above the base 18. There is a first driving motor 19 at the lower part of the base 18. The lower end of the feed pipe 21 is a spiral bearing seat 20. The spiral bearing seat 20 is fixed in the middle of the base 18. The upper part of the spiral bearing seat 20 is connected to the feed pipe 21. A support frame is provided in the middle of the feed pipe 21 and is connected to the upper part of the cooling tube 13; a first screw rod 23.2 passes through the lower part of the feed pipe 21 and the spiral bearing seat 20, and the lower part is connected to the first driving motor 19 and is driven to rotate by the first driving motor 19.

[0048] Three specific embodiments of the graphite purification furnace are given in this application. Refer to the attached Figure 1 As shown, the first embodiment has been described in more detail above. Now, the main differences between the second embodiment, the third embodiment and the first embodiment, that is, the second material conveying mechanism 16 and the first material conveying mechanism, will be introduced:

[0049] As Figure 2 shown, in the second embodiment, the second material conveying mechanism 16 includes a horizontally arranged screw conveying device. An outlet bin 14.1 is connected to the upper part of the second material conveying mechanism 16. The aggregate tank 17 is connected to the lower part of the second material conveying mechanism 16 through an outlet pipe 37. The upper and lower openings of the second material conveying mechanism 16 are staggered. The purified graphite material enters from the upper part and exits from the lower part of the second material conveying mechanism 16, and is continuously fed into the aggregate tank 17 under the drive of the screw conveying device. The second screw rod 23 rotates under the drive of the drive motor, so as to realize the transmission and control of the material. Power is provided by a frequency conversion motor, and the rotation speed of the frequency conversion motor is controlled by the signal of the height measuring module. When the graphite level in its exhaust cavity 28 is high, the rotation speed of the turbine of the conveying mechanism 16 is accelerated. When the graphite level in its exhaust cavity 28 is low, the rotation speed of the conveying mechanism 16 is reduced; further, the same is true for the second material conveying mechanism. Furthermore, through the program system, the graphite level in the exhaust cavity 28, that is, the balance of the feeding and discharging material flow, can be efficiently, accurately and reliably controlled.

[0050] In the second embodiment, the feeding channel 33 in the first material conveying mechanism is horizontally arranged, and the second screw rod 23 is arranged in the feeding channel 33 to horizontally convey the graphite material. The feeding hopper 24.1 communicates with the upper part of the feeding channel 33, so that the graphite material is continuously conveyed into the feeding pipe 21 under the drive of the second screw rod 23.

[0051] As Figure 3 shown, in the third embodiment, based on the design schemes of the second material conveying mechanism and the first material conveying mechanism in the second embodiment, the present invention further adopts the method of induction heating by the heating pipe 12 for high-temperature purification of the material. The heating pipe 12 includes a pipe body and an induction heater 39. The induction heater 39 is a method of heating using the principle of electromagnetic induction. By energizing the induction heater 39, an alternating magnetic field is generated, causing eddy currents to be generated inside the object to be heated, and heating the object by the heat generated by the eddy currents. The pipe body is mainly used for conveying the material. In the third embodiment, the heating pipe 12 and the protective sleeve 32 also become conductors and are heated by the eddy currents. Induction heating is usually applied to the heating of conductive materials and has the advantages of fast heating speed, high energy efficiency, precise temperature control, etc.

[0052] The present application further proposes a graphite purification method for a vertical graphite purification furnace, which includes steps S1 to S4, as well as material pretreatment performed before step S1.

[0053] Step S1: Convey the material to be purified, perform step-by-step preheating, and perform inerting treatment.

[0054] First, in step S1, the material to be purified is preheated by the preheating coil in the automatic feeding tank, enters the transfer tank 25, is evacuated and then purged with an inert gas to complete the inerting treatment; then the material to be purified in the transfer tank enters the feeding tank 24 and then enters the feeding hopper 24.1, and then the material to be purified is conveyed into the heating pipe 12. In the heating pipe 12, the material to be purified exchanges heat with the refined material after high-temperature purification, and is preheated thereby. This preheating process helps to increase the temperature of the material to be purified, and through heat exchange with the refined material, promotes the rapid volatilization, decomposition or combustion of impurities and volatile substances, thereby reducing the adverse effects in the subsequent purification process.

[0055] Step S2: High-temperature purify the material to be purified

[0056] In step S2, the preheated material to be purified travels to the top in the heating pipe 12 and then spreads out into the high-temperature zone. Further material enters the high-temperature zone of the annular space 40 formed by the top of 12 and the protective sleeve 32. At high temperature, the impurities in the graphite material evaporate and gasify, forming impurity aerosols in the exhaust gas 28, which are discharged from the furnace body by the exhaust mechanism, thereby achieving the purpose of the purification purity of the graphite.

[0057] Step S3: Heat exchange cooling and physical cooling

[0058] The refined material after high-temperature purification descends in the annular space 40 and exchanges heat with the material to be purified in the feed pipe 12, achieving the purpose of cooling. The refined material obtained after high-temperature purification by the heating pipe exchanges heat with the material to be purified before being transported to the heating pipe. At the same time, the refined material is physically cooled to further reduce its temperature. Through this step, the cooling of the graphite material and stable temperature control can be realized, preventing overheating and destroying the heat balance, improving the cooling efficiency and achieving an energy-saving effect.

[0059] Step S4: Collect the cooled refined material

[0060] Finally, in Step S4, the cooled refined material is collected. These cooled refined materials have a highly pure quality and ideal physical properties.

[0061] It is particularly emphasized that in Step S1, pretreatment of the material is also carried out. The pretreatment method includes evacuating the material to be purified, filling it with an inert gas to displace the adsorbed water and oxygen in the material to be purified, and making the pressure of the displaced inert gas slightly higher than the atmospheric pressure. By displacing with the inert gas and increasing the pressure, the oxygen content in the material to be purified can be reduced, and the slightly higher air pressure helps the raw material to smoothly enter the next material tank. During the graphite purification process, oxygen in the high-temperature environment may cause oxidation of the heating pipe and the protective sleeve, shortening the service life of the equipment, increasing costs, and reducing production efficiency. Further, the pretreatment can effectively prevent the occurrence of the furnace fire phenomenon caused by the oxidation of the heat-insulating filler and improve the safety of production.

[0062] In summary, the purification method of this vertical graphite purification furnace realizes the efficient purification and cooling of graphite materials through steps such as preheating, high-temperature purification, heat exchange cooling, and physical cooling, as well as the pretreatment of materials, while ensuring the purity and quality of graphite materials. The vertical carbon tube furnace can achieve automatic feeding and continuous production, reducing process instability caused by human factors. The present invention adopts a vertical structure, does not require the use of graphite boats, and is not directly connected to the atmospheric environment. The service life of the heating tube 12 can be extended from 1 month to 5 months of the vertical graphite furnace, and the total product cost can be reduced by 5%. This application can enlarge the diameter of the heating tube 12, and the effective working volume during purification can be increased by 160%. At the same time, the graphite boat is removed from the working cavity, and the production capacity within the same time can be increased to 3.4 times the original. Through test calculation, the power of the vertical graphite purification furnace is 2.3 times that of the horizontal graphite furnace, and the energy consumption per unit output is reduced by 33%. Further, since the cylinder 5 is filled with an inert gas cycle, the possibility of impurities penetrating into the furnace body and eroding the thermal insulation material is greatly reduced, and the possibility of a large amount of gas generated by oxidizing the thermal insulation material causing a fire hazard is greatly reduced, resulting in an extended equipment maintenance cycle and an extended service life of the thermal insulation material. Combined with the reduction of unit energy consumption, the cost of vulnerable parts, and the labor cost, it is comprehensively concluded that the product cost is reduced by 20% compared with the horizontal graphite purification furnace, which can greatly improve the product competitiveness.

[0063] Although the present invention has been disclosed above with preferred embodiments, the above preferred embodiments are not intended to limit the present invention. Those of ordinary skill in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A vertical graphite purification furnace, characterized in that, it includes a feed pipe, a heating pipe, a cylinder body, a protective sleeve, a first material conveying mechanism and an exhaust mechanism. The feed pipe, the heating pipe, the protective sleeve and the cylinder body are sleeved in sequence from inside to outside and have intervals between them. The lower end of the feed pipe is connected to the first material conveying mechanism. The upper end of the feed pipe is a discharge port, and the horizontal height of the discharge port is lower than the top of the heating pipe. The space between the discharge port and the top inside the heating pipe serves as an exhaust chamber, and the exhaust chamber is communicated with the exhaust mechanism.

2. The vertical graphite purification furnace according to claim 1, characterized in that, the vertical graphite purification furnace further includes a cooling pipe. The cooling pipe is connected to the lower end of the heating pipe. The feed pipe passes through the bottom end of the cooling pipe and is connected to the first material conveying mechanism. The bottom of the cooling pipe is the discharge port.

3. The vertical graphite purification furnace according to claim 1, characterized in that, installation ports are respectively provided at the upper and lower ends of the cylinder body. A tapered sleeve is provided in the installation port, and the upper and lower end portions of the heating pipe are respectively arranged in the tapered sleeve. A sealing and heat-insulating sleeve is further provided between the tapered sleeve and the installation port. Power connection modules for connecting to the power supply of the heating pipe are further provided on the outer sides of the upper and lower tapered sleeves, and an insulating layer is provided on the surface of the power connection module.

4. The vertical graphite purification furnace according to claim 3, characterized in that, the upper and lower ends of the protective sleeve abut against the tapered sleeve, and an insulating ring is provided between the protective sleeve and the tapered sleeve.

5. The vertical graphite purification furnace according to claim 1, characterized in that, there is a cavity between the protective sleeve and the heating pipe, and an inert protective gas is filled in the cavity; a heat-insulating cavity is provided between the protective sleeve and the cylinder body, and heat-insulating materials are filled in the heat-insulating cavity. The protective sleeve allows the inert protective gas to permeate.

6. The vertical graphite purification furnace according to claim 3, characterized in that, cooling water jackets are further provided on the surface of the cylinder body and the surface of the power connection module. A cooling water circulation channel is provided inside the cooling water jacket. A cooling water circulation channel is provided outside the cooling pipe. The lower end of the cooling pipe is further communicated with a transition pipe. The lower end of the transition pipe is communicated with an aggregate tank. A base is provided at the lower end of the aggregate tank. A valve is further provided on the transition pipe. A second material conveying mechanism is further provided between the transition pipe and the aggregate tank. The second material conveying mechanism is used to convey graphite downward or horizontally into the aggregate tank.

7. The vertical graphite purification furnace according to claim 1, characterized in that, the exhaust mechanism includes an exhaust pipe, an exhaust device and a dredging device. One end of the exhaust pipe is communicated with the exhaust chamber, and the other end is communicated to the outside of the cylinder body and is connected to the exhaust device and the dredging device; and there is a filter element in the exhaust pipe. The filter element is used to adsorb impurities volatilized at high temperature, and the filter element is a high-temperature resistant material.

8. The vertical graphite purification furnace according to claim 1, characterized in that, The first material conveying mechanism includes a feeding channel, a screw rod, a first driving motor, and an automatic feeding tank. The feeding channel is communicated with the lower part of the feeding pipe. The screw rod is arranged in the feeding channel. The first driving motor is in transmission connection with the screw rod. The automatic feeding tank is used for injecting graphite into the feeding channel.

9. The vertical graphite purification furnace according to claim 8, characterized in that the automatic feeding tank includes a feeding hopper, a feeding trough, a transfer trough, and a material conveying trough. The lowest horizontal position of the feeding hopper is connected to the inside of the feeding pipe. The material conveying trough is arranged at the highest horizontal position of the feeding hopper. The transfer trough is connected to the upper end of the material conveying trough. The feeding trough is connected to the upper end of the transfer trough. Switch valves are arranged on the communication channels between the transfer trough and the material conveying trough, and between the transfer trough and the feeding trough. The transfer trough is provided with an air extraction port and an inert gas filling port. And preheating coils are arranged on the inner sides of the feeding trough and / or the transfer trough and / or the material conveying trough.

10. A graphite purification method for a vertical graphite purification furnace, characterized in that the graphite purification method includes: Step S1, performing material pretreatment. After evacuating the material to be purified in the automatic feeding tank, filling it with inert gas to replace the air in the material to be purified with inert gas, and preheating the material; Step S2, conveying the material to be purified to the heating pipe for high-temperature purification. The material to be purified exchanges heat with the refined material after high-temperature purification, so that the material to be purified continues to be preheated; Step S3, obtaining the refined material after high-temperature purification by the heating pipe. The refined material output by the heating pipe exchanges heat with the material to be purified before being conveyed to the heating pipe to physically cool the refined material; Step S4, collecting the cooled refined material.

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