Two-stage gasification device for graphite regeneration and two-stage gasification process thereof

Abstract

The invention belongs to the technical field of gasification devices, and particularly relates to a two-stage gasification device for graphite regeneration and a two-stage gasification process thereof.The two-stage gasification device comprises a first-stage gasification device, a conveying device and a second-stage gasification device, a furnace tube is rotatably arranged in a first gasification furnace, and a first heater is arranged on the periphery of the inner wall of the first gasification furnace; the second-section gasification equipment comprises a second gasification furnace, a heating cavity is formed in the second gasification furnace, a furnace door is arranged at the upper end of the second gasification furnace, and a second heater is arranged in the heating cavity; according to the invention, through the first gasification furnace, the first heater and the rotatable furnace tube, moisture in the graphite obtained through aeration separation is dried, and organic impurities are removed, so that the graphite is subjected to secondary gasification, and the graphite is discharged from the furnace tube and is conveyed into the heating cavity of the second gasification furnace through the conveying equipment. Transmission equipment is arranged for cooling the graphite subjected to primary gasification, and redundant metal impurities in the graphite are further removed through a second gasification furnace and a second heater, so that the purity and the performance of the graphite are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of gasification devices, and in particular relates to a two-stage gasification device for graphite regeneration and a two-stage gasification process thereof. Background Art

[0002] Waste batteries are the main source of copper-containing negative electrode plates. These batteries need to be recycled after their service life to recover valuable metal components. Recycling copper and graphite in waste batteries can not only reduce resource waste, but also reduce the production cost of new materials. At the same time, battery recycling is also conducive to reducing the pollution of waste to the environment and is an important sustainable development measure.

[0003] Graphite regeneration is an important technology to effectively improve graphite utilization and reduce graphite waste. In the process of graphite regeneration, a common challenge is how to effectively separate and remove metal impurities from graphite. The traditional way to remove metal impurities is to directly heat it to high temperature. However, this method has high energy consumption and is easy to decompose at high temperature to produce harmful gases such as dioxins, causing air pollution. In addition, direct high-temperature treatment is prone to cause excessive sintering of materials or other forms of thermal damage, affecting the final quality of the product. Summary of the invention

[0004] In view of this, in order to solve the problems existing in the prior art, the purpose of the present invention is to provide a two-stage gasification device for graphite regeneration and a two-stage gasification process thereof, which has the effects of gradually removing impurities, avoiding the generation of harmful substances, preventing material damage, high energy utilization efficiency and extending the service life of the equipment.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A two-stage gasification device for graphite regeneration, comprising: a first-stage gasification device, a transmission device and a second-stage gasification device which are sequentially connected, wherein the first-stage gasification device comprises a first gasification furnace, wherein a furnace tube is rotatably arranged in the first gasification furnace, and a graphite mixture to be heated enters from one end of the furnace tube, and a first heater is arranged on a circumference of the inner wall of the first gasification furnace, and the first heater is located outside the furnace tube;

[0007] The two-stage gasification equipment includes a second gasification furnace, a heating chamber is provided in the second gasification furnace, a furnace door for adding graphite after a first stage of gasification is provided at the upper end of the second gasification furnace, and a second heater is provided in the heating chamber;

[0008] One end of the transmission device is connected to the other end of the furnace tube, and the other end of the transmission device is arranged above the furnace door;

[0009] After a period of gasification, the graphite is discharged from the other end of the furnace tube and transported to the heating chamber of the second gasifier through the transmission device.

[0010] The specific technical effect is: through the first gasifier, the first heater and the rotatable furnace tube, the moisture in the graphite obtained by aeration separation is dried, and the organic impurities are removed to keep the graphite dry. By setting up a transmission device for cooling, the graphite after the first stage of gasification needs to be cooled to prevent thermal shock when directly entering the high-temperature second stage of gasification. The second gasifier and the second heater are used to further remove excess metal impurities in the graphite, and secondary graphitization treatment is carried out to improve the purity and performance of the graphite.

[0011] Furthermore, the first-stage gasification equipment also includes a driving assembly, a first mounting base and a first feed hopper. The driving assembly and the first gasification furnace are both mounted on the first mounting base. The upper end of the driving assembly is sleeved on the other end of the furnace tube. The driving assembly is used to drive the furnace tube to rotate. The first feed hopper is arranged on one end of the furnace tube.

[0012] Furthermore, the driving assembly includes a passive wheel and two driving parts, the two driving parts are respectively arranged on both sides of the passive wheel, each of the driving parts includes a driving wheel, a driving motor and a motor mounting seat, the passive wheel is sleeved on the other end of the furnace tube, the driving wheel is installed on the moving end of the driving motor and meshes with the passive wheel for transmission, the driving motor is installed on the motor mounting seat, and the motor mounting seat is installed on the first mounting base.

[0013] The specific technical effects are: the passive wheel driving wheel transmission has a simple structure, strong ability to withstand impact and vibration, long service life, high reliability, lower noise and smoother transmission, and the passive wheel driving wheel transmission drives the furnace tube to rotate 360 ​​degrees, which is suitable for uniform sintering of graphite.

[0014] Furthermore, the axis of the furnace tube is arranged to be inclined downward toward the direction close to the transmission device, the axis of the moving end of the drive motor is arranged parallel to the axis of the furnace tube, the rotation direction between the two drive wheels is the same, and the rotation direction between the drive wheel and the driven wheel is opposite.

[0015] The specific technical effect is that the inclined furnace tube is more conducive to material discharge.

[0016] Furthermore, a handle is provided on the furnace door of the second gasification furnace.

[0017] Furthermore, the transmission equipment includes an intermediate buffer tank and a conveyor connected in sequence, one end of the intermediate buffer tank is connected to the other end of the furnace tube through a first feed pipe, the other end of the intermediate buffer tank is connected to one end of the conveyor through a first discharge pipe, and the other end of the conveyor is arranged above the furnace door.

[0018] The specific technical effect is: by setting up transmission equipment for cooling, the graphite after the first stage of gasification needs to be cooled to prevent thermal shock when directly entering the high-temperature second stage of gasification, and the intermediate buffer tank is used to temporarily store the graphite after the first stage of gasification.

[0019] Furthermore, the conveyor includes a support seat, a conveying bin, a second feed hopper, a ventilation pipe and a conveying structure. The conveying bin is installed on the support seat. A transportation channel is opened in the conveying bin from the intermediate buffer tank to the direction of the furnace door. The conveying structure is arranged in the transportation channel for transporting graphite to the second gasification furnace. The second feed hopper is arranged on one end of the conveying bin, and the second feed hopper is connected to the first discharge pipe. A drop pipe is arranged at the lower end of the other end of the conveying bin, and the drop pipe is arranged above the furnace door. The ventilation pipe is connected from the outside of the conveying bin to the conveying channel.

[0020] The specific technical effect is: a conveying structure is used to transport a section of gasified graphite to the second gasification furnace, and in the conveying process, inert gas is introduced into the conveying bin through a vent pipe, and the graphite is transported in an inert gas environment to prevent oxidation.

[0021] Furthermore, the conveying structure is a conveyor belt or a spiral conveying shaft.

[0022] The specific technical effect is: the conveyor belt can use a high temperature resistant conveyor belt.

[0023] Furthermore, the first-stage gasification equipment also includes: a feeding trolley, a material transport track and a gasification chamber. The first gasification furnace is arranged in the gasification chamber. The material transport track is laid from the outside of the gasification chamber to the bottom of one end of the first gasification furnace. The feeding trolley is slidably connected to the material transport track.

[0024] A two-stage gasification process, using the two-stage gasification device for graphite regeneration as described above to remove graphite and metal impurities, includes the following steps:

[0025] Step S1, after the graphite mixture to be heated is delivered to one end of the furnace tube by a feeding trolley, the empty feeding trolley exits the gasification chamber, and the door of the gasification chamber is closed;

[0026] Step S2, turning on the first heater, adjusting the first heater to the heating temperature required for the first stage of gasification through the external temperature control system, setting the first stage of gasification temperature to 300° C. to 400° C., turning on the drive motor, driving the furnace tube to rotate through the passive wheel and the drive wheel, and setting the first stage of gasification time to 1 h to 3 h;

[0027] Step S3, the graphite obtained in step S2, from which water and organic impurities are removed, is fed into an intermediate buffer tank through a first feed pipe for cooling;

[0028] Step S4, the graphite cooled in step S3 enters the conveying bin through the first discharge pipe and the second feed hopper, and the graphite is conveyed from the discharge pipe to the second gasification furnace through the conveying structure. During the conveying, an inert gas is introduced into the conveying bin through the vent pipe;

[0029] Step S5, close the furnace door, turn on the second heater, adjust the second heater to the heating temperature required for the second-stage gasification through the external temperature control system, set the second-stage gasification temperature to 2800° C. to 3000° C., and set the second-stage gasification time to 2 h to 4 h;

[0030] Step S6: After the two-stage gasification in step S5, graphite with metal impurities removed is obtained.

[0031] The specific technical effects are: removing moisture and organic impurities at a lower temperature, avoiding energy waste and unnecessary complexity of high-temperature treatment; organic matter is removed at a low temperature to avoid decomposition at high temperature to produce harmful gases such as dioxins, reducing air pollution and protecting the environment; by gradually increasing the temperature, excessive sintering of materials or other forms of thermal damage can be avoided, and the quality of the final product can be improved; at high temperatures, metal impurities can be completely removed, and at the same time, high temperature conditions help to optimize the crystal structure of graphite and improve its purity and performance; by removing most of the impurities at a lower temperature first, the time and energy required for high-temperature treatment can be reduced, saving energy and reducing costs. The two-stage gasification process saves about 25% of energy compared to single high-temperature treatment; gradually increasing the temperature can reduce the thermal load and stress of the equipment, extend the service life of the equipment, and reduce maintenance and replacement costs; staged gasification can better control the reaction process and parameters of each treatment stage, ensure the stability and controllability of the treatment process, especially in the high-temperature stage, to ensure the best treatment effect; by gradually increasing the temperature in stages, the risk of sudden thermal reactions and equipment failures can be reduced, and the overall safety of the process can be improved.

[0032] The beneficial effects of the present invention are:

[0033] (1) Dry the water in the graphite obtained by aeration separation and remove organic impurities through the first gasification furnace, the first heater and the rotatable furnace tube to keep the graphite dry. Set up a transmission device for cooling. The graphite after the first stage of gasification needs to be cooled to prevent thermal shock when directly entering the high-temperature second stage of gasification. Use the second gasification furnace and the second heater to further remove excess metal impurities in the graphite, and perform secondary graphitization to improve the purity and performance of the graphite.

[0034] (2) Remove moisture and organic impurities at a lower temperature to avoid energy waste and unnecessary complexity of high-temperature treatment. By removing most impurities at a lower temperature first, the time and energy required for high-temperature treatment can be reduced, saving energy and reducing costs. The two-stage gasification process saves about 25% of energy compared to a single high-temperature treatment.

[0035] (3) Organic matter is removed at low temperatures to avoid decomposition at high temperatures to produce harmful gases such as dioxins, thereby reducing air pollution and protecting the environment;

[0036] (4) By gradually increasing the temperature, excessive sintering or other forms of thermal damage to the material can be avoided, thereby improving the quality of the final product; at high temperatures, metal impurities can be completely removed, and high temperature conditions help optimize the crystal structure of graphite, thereby improving its purity and performance;

[0037] (5) Gradually increasing the temperature can reduce the heat load and stress of the equipment, extend the service life of the equipment, and reduce maintenance and replacement costs;

[0038] (6) Staged gasification can better control the reaction process and parameters of each treatment stage, ensuring the stability and controllability of the treatment process, especially in the high-temperature stage, to ensure the best treatment effect. By gradually increasing the temperature in stages, the risk of sudden thermal reactions and equipment failures can be reduced, thereby improving the overall safety of the process.

[0039] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0041] Figure 1 It is a partial structural schematic diagram of a two-stage gasification device for graphite regeneration of the present invention;

[0042] Figure 2 is a half-section view of a two-stage gasification device for graphite regeneration according to the present invention;

[0043] Figure 3 It is a structural schematic diagram of a gasification device of the present invention;

[0044] Figure 4 It is a structural schematic diagram of the two-stage gasification equipment of the present invention;

[0045] Figure 5 It is a cross-sectional view of the two-stage gasification equipment of the present invention.

[0046] In the figure:

[0047] 1. The first gasifier; 2. The furnace tube; 3. The first heater; 4. The second gasifier; 5. The heating chamber; 6. The furnace door; 7. The second heater; 8. The first mounting base; 9. The first feed hopper; 10. The passive wheel; 11. The driving wheel; 12. The driving motor; 13. The motor mounting base; 14. The handle; 15. The intermediate buffer tank; 16. The conveyor; 17. The support base; 18. The conveying bin; 19. The second feed hopper; 20. The ventilation pipe; 21. The conveying structure; 22. The feeding trolley; 23. The material transport track; 24. The gasification chamber. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] like Figures 1 to 5 As shown, a two-stage gasification device for graphite regeneration and a two-stage gasification process thereof, a first-stage gasification device, a transmission device and a second-stage gasification device are sequentially connected and arranged, the first-stage gasification device comprises a first gasification furnace 1, a furnace tube 2 is rotatably arranged in the first gasification furnace 1, the graphite mixture to be heated enters from one end of the furnace tube 2, a first heater 3 is arranged on a circle of the inner wall of the first gasification furnace 1, and the first heater 3 is located outside the furnace tube 2;

[0050] The second-stage gasification equipment includes a second gasification furnace 4, a heating chamber 5 is provided in the second gasification furnace 4, a furnace door 6 for adding graphite after a first stage of gasification is provided at the upper end of the second gasification furnace 4, and a second heater 7 is provided in the heating chamber 5;

[0051] One end of the transmission device is connected to the other end of the furnace tube 2, and the other end of the transmission device is arranged above the furnace door 6;

[0052] After a period of gasification, the graphite is discharged from the other end of the furnace tube 2 and transported to the heating chamber 5 of the second gasification furnace 4 through a transmission device.

[0053] It should be noted here that: the moisture in the graphite obtained by aeration separation is dried and organic impurities are removed through the first gasification furnace 1, the first heater 3 and the rotatable furnace tube 2, so that the graphite is kept in a dry state. By setting up a transmission device for cooling, the graphite after the first stage of gasification needs to be cooled to prevent thermal shock when directly entering the high-temperature second stage of gasification. The second gasification furnace 4 and the second heater 7 are used to further remove excess metal impurities in the graphite, and secondary graphitization treatment is performed to improve the purity and performance of the graphite.

[0054] The first-stage gasification equipment also includes a driving assembly, a first mounting base 8 and a first feed hopper 9. The driving assembly and the first gasification furnace 1 are both mounted on the first mounting base 8. The upper end of the driving assembly is sleeved on the other end of the furnace tube 2. The driving assembly is used to drive the furnace tube 2 to rotate. The first feed hopper 9 is arranged on one end of the furnace tube 2.

[0055] The driving assembly includes a passive wheel 10 and two driving parts, which are respectively arranged on both sides of the passive wheel 10. Each driving part includes a driving wheel 11, a driving motor 12 and a motor mounting seat 13. The passive wheel 10 is sleeved on the other end of the furnace tube 2. The driving wheel 11 is installed on the moving end of the driving motor 12 and meshes with the passive wheel 10 for transmission. The driving motor 12 is installed on the motor mounting seat 13, and the motor mounting seat 13 is installed on the first mounting base 8.

[0056] It should be noted here that the transmission structure using the passive wheel 10 and the driving wheel 11 is simple, has a strong ability to withstand impact and vibration, has a long service life, is highly reliable, generates lower noise and is smoother, and the passive wheel driving wheel transmission drives the furnace tube 2 to rotate 360°, which is suitable for uniform sintering of graphite.

[0057] The axis of the furnace tube 2 is tilted downward toward the direction close to the transmission equipment, the axis of the moving end of the drive motor 12 is parallel to the axis of the furnace tube 2, the rotation directions of the two drive wheels 11 are the same, and the rotation directions of the drive wheel 11 and the driven wheel 10 are opposite.

[0058] It should be noted here that the inclined furnace tube 2 is more conducive to material discharge.

[0059] The second gasification furnace 4 is an ultra-high temperature induction heating furnace. The second heater 7 includes an electromagnetic induction heating coil and a heating controller. The heating controller is installed on the second gasification furnace 4. The electromagnetic induction heating coil is spiral and is only in the heating chamber 5.

[0060] A handle 14 is provided on the furnace door 6 of the second gasification furnace 4 .

[0061] The transmission equipment includes an intermediate buffer tank 15 and a conveyor 16 connected in sequence. One end of the intermediate buffer tank 15 is connected to the other end of the furnace tube 2 through a first feed pipe, and the other end of the intermediate buffer tank 15 is connected to one end of the conveyor 16 through a first discharge pipe. The other end of the conveyor 16 is arranged above the furnace door 6.

[0062] It should be noted here that: by setting up a transmission device for cooling, the graphite after the first stage of gasification needs to be cooled to prevent thermal shock when directly entering the high-temperature second stage of gasification, and the intermediate buffer tank 15 is used to temporarily store the graphite after the first stage of gasification.

[0063] The conveyor 16 includes a support seat 17, a conveying bin 18, a second feed hopper 19, a ventilation pipe 20 and a conveying structure 21. The conveying bin 18 is installed on the support seat 17. A transportation channel is opened in the conveying bin 18 from the intermediate buffer tank 15 to the direction of the furnace door 6. The conveying structure 21 is arranged in the transportation channel for transporting graphite to the second gasification furnace 4. The second feed hopper 19 is arranged on one end of the conveying bin 18. The second feed hopper 19 is connected to the first discharge pipe. A drop pipe is arranged at the lower end of the other end of the conveying bin 18. The drop pipe is arranged above the furnace door 6. The ventilation pipe 20 is connected from the outside of the conveying bin 18 to the conveying channel.

[0064] It should be noted here that: a conveying structure 21 is used to transport a section of gasified graphite to the second gasification furnace 4, and inert gas is introduced into the conveying bin 18 through the vent pipe 20 during the transportation process, and the graphite is transported in an inert gas environment to prevent oxidation.

[0065] The conveying structure 21 is a conveying belt or a spiral conveying shaft.

[0066] It should be noted here that the conveyor belt can be a high temperature resistant conveyor belt.

[0067] The first stage gasification equipment also includes: a feeding trolley 22, a material transport track 23 and a gasification chamber 24. The first gasification furnace 1 is arranged in the gasification chamber 24. The material transport track 23 is laid from the outside of the gasification chamber 24 to the bottom of one end of the first gasification furnace 1. The feeding trolley 22 is slidably connected to the material transport track 23.

[0068] A two-stage gasification process, using the two-stage gasification device for graphite regeneration as described above to remove graphite and metal impurities, includes the following steps:

[0069] Step S1, after the graphite mixture to be heated is delivered to one end of the furnace tube 2 by the feeding trolley 22, the unloaded feeding trolley 22 withdraws from the gasification chamber 24, and the door of the gasification chamber 24 is closed;

[0070] Step S2, turn on the first heater 3, adjust the first heater 3 to the heating temperature required for the first stage of gasification through the external temperature control system, set the first stage of gasification temperature to 300° C. to 400° C., turn on the drive motor 12, drive the furnace tube 2 to rotate through the passive wheel 10 and the drive wheel 11, and set the first stage of gasification time to 1 h to 3 h;

[0071] Step S3, the graphite obtained in step S2, from which water and organic impurities are removed, is fed into the intermediate buffer tank 15 through the first feed pipe for cooling;

[0072] Step S4, the graphite cooled in step S3 enters the conveying bin 18 through the first discharge pipe and the second feed hopper 19, and is conveyed from the discharge pipe to the second gasification furnace 4 through the conveying structure 21. During the conveying, an inert gas is introduced into the conveying bin 18 through the vent pipe 20;

[0073] Step S5, close the furnace door 6, turn on the second heater 7, adjust the second heater 7 to the heating temperature required for the second-stage gasification through the external temperature control system, set the second-stage gasification temperature to 2800° C. to 3000° C., and set the second-stage gasification time to 2 h to 4 h;

[0074] Step S6: After the two-stage gasification in step S5, graphite with metal impurities removed is obtained.

[0075] It should be noted here that: removing moisture and organic impurities at a lower temperature avoids energy waste and unnecessary complexity of high-temperature treatment; organic matter is removed at a low temperature to avoid decomposition at high temperature to produce harmful gases such as dioxins, reduce air pollution, and protect the environment; by gradually increasing the temperature, excessive sintering of materials or other forms of thermal damage can be avoided, and the quality of the final product can be improved; at high temperatures, metal impurities can be completely removed, and at the same time, high temperature conditions help to optimize the crystal structure of graphite and improve its purity and performance; by removing most of the impurities at a lower temperature first, the time and energy required for high-temperature treatment can be reduced, saving energy and reducing costs. The two-stage gasification process saves about 25% of energy compared to a single high-temperature treatment; gradually increasing the temperature can reduce the thermal load and stress of the equipment, extend the service life of the equipment, and reduce maintenance and replacement costs; staged gasification can better control the reaction process and parameters of each treatment stage, ensure the stability and controllability of the treatment process, especially in the high-temperature stage, to ensure the best treatment effect; by gradually increasing the temperature in stages, the risk of sudden thermal reactions and equipment failures can be reduced, and the overall safety of the process can be improved.

[0076] The purpose of setting the first stage gasification temperature to 300℃~400℃ is:

[0077] (1) Remove moisture

[0078] In the temperature range of 300℃ to 400℃, the moisture in the material will be effectively evaporated and removed. This step is very important to prevent the risk of rapid gasification and explosion at higher temperatures (such as 2800℃). By removing moisture, damage to equipment and structural changes in materials can be avoided.

[0079] (2) Decomposition of low-temperature volatile organic impurities

[0080] In the copper-containing negative electrode materials, there may be some residual binders (such as PVDF) and solvents (such as NMP). These substances can be removed by pyrolysis or evaporation in the range of 300°C to 400°C, thereby reducing their interference and the generation of harmful gases during high-temperature treatment.

[0081] (3) Reduce energy consumption

[0082] Removing volatile organic impurities and moisture at a lower temperature can reduce the energy consumption of subsequent high-temperature treatment. If directly treated at high temperature, all volatile components will consume more energy to gasify. By pre-treating at low temperature first, the energy consumption of the high-temperature stage can be reduced, making the overall process more energy-efficient (e.g., from 800kWh to 400kWh).

[0083] It should be noted here that:

[0084] PVDF (polyvinylidene fluoride): In the temperature range of 300℃ to 400℃, PVDF will begin to thermally decompose, producing hydrofluoric acid (HF) and some low molecular weight fluorine-containing organic substances (such as fluorinated hydrocarbon compounds). Due to the low temperature, this decomposition reaction is relatively slow, and the by-products produced are relatively small, mainly hydrofluoric acid (HF) and a small amount of tetrafluoroethylene and other gases. Decomposition under this temperature condition can avoid violent reactions at higher temperatures and control the amount of harmful gases generated.

[0085] Removal effect: At 300℃~400℃, the pyrolysis of PVDF is relatively mild and the removal efficiency is high, but it will produce a certain amount of HF gas and other volatile organic compounds. An effective gas treatment system is required to capture these harmful gases.

[0086] If directly treated at 1700℃, PVDF will undergo violent pyrolysis and combustion, generating more fluorides (such as hydrofluoric acid HF) and some more complex fluorocarbons. The decomposition reaction rate at this high temperature is very fast, which may lead to the generation of a large amount of toxic gases (such as HF and carbon tetrafluoride, etc.). In addition, the high temperature of 1700℃ may also cause equipment corrosion and other uncontrollable side reactions.

[0087] Removal effect: Although high temperature can ensure the complete removal of PVDF, it will produce more harmful byproducts, such as hydrofluoric acid and other toxic fluorides. It is very important to control the emission of these harmful substances.

[0088] NMP (N-methylpyrrolidone): In the temperature range of 300℃ to 400℃, NMP will also undergo thermal decomposition to generate some nitrogen oxides (NO x ), carbon monoxide (CO), carbon dioxide (CO2) and other low molecular weight nitrogen-containing organic compounds. The decomposition temperature of NMP is relatively low, so within this temperature range, most of NMP will be evaporated or pyrolyzed and removed.

[0089] Removal effect: In this temperature range, NMP can be removed more effectively and the harmful gases produced are relatively small. Lower temperatures can reduce the generation of toxic byproducts.

[0090] If directly treated at 1700℃, NMP will burn completely or decompose into simple molecules such as carbon dioxide (CO2), water (H2O), nitrogen oxides (NO x ) and carbon monoxide (CO). Due to the extremely high temperature, the decomposition reaction is very thorough, but it may also produce a large amount of nitrogen oxides, which are very harmful to the environment and health.

[0091] Removal effect: NMP can be completely removed at high temperatures, but it will produce a large amount of gases such as nitrogen oxides and carbon monoxide, which requires strict gas treatment and monitoring measures.

[0092] Therefore, in summary, compared with direct treatment at a high temperature of 1700°C, the advantages of setting the first stage gasification temperature to 300°C to 400°C are as follows:

[0093] Removal efficiency: At a high temperature of 1700°C, PVDF and NMP will decompose more thoroughly, but will produce a large amount of harmful gases, such as hydrofluoric acid (HF), nitrogen oxides (NO x ) etc. At 300℃~400℃, although the removal efficiency is slightly lower, it can better control the generation of harmful gases and reduce the impact on the environment.

[0094] Energy consumption: The energy required for temperature conditions of 300℃~400℃ is much lower than that of 1700℃, so using lower temperature pretreatment can significantly reduce overall energy consumption.

[0095] Equipment loss and safety: A high temperature of 1700°C will increase the heat load of the equipment and may cause corrosion or damage to the furnace. In contrast, a processing temperature of 300°C to 400°C is milder, with less loss to the equipment and higher safety.

[0096] The purpose of setting the second stage gasification temperature to 2800℃~3000℃ is:

[0097] (1) Realize secondary graphitization

[0098] Temperature requirements for secondary graphitization: Graphitization is usually carried out at high temperatures of 2000℃ to 3000℃. The graphitization process requires a sufficiently high temperature to break the disordered structure in the carbon material and rearrange the carbon atoms into a highly ordered graphite layer structure. The graphitization process will be more thorough at 2800℃ or above, which can significantly improve the crystallinity and purity of graphite and is suitable for high-performance applications.

[0099] (2) Removal of metal impurities

[0100] Removal of metal impurities: Most metal impurities, such as copper, iron, nickel, etc., have high boiling points. In order to evaporate or oxidize these metals into a form that can be removed, higher temperatures are required. For example, the boiling point of copper is 2562°C, the boiling point of iron is 2862°C, and the boiling point of nickel is 2913°C. Therefore, the temperature needs to be set at least 2800°C to 3000°C or higher to effectively remove these metal impurities.

[0101] It should be noted here that at a temperature of 2800°C to 3000°C or higher, not only can secondary graphitization be fully achieved, but also all possible metal impurities and other non-metallic impurities (such as sulfur, phosphorus, etc.) can be oxidized or volatilized, and finally high-purity graphite can be obtained.

[0102] The raw material of the copper-containing negative electrode plate is set to: 100kg, with a copper content of 20% and a graphite content of 60%.

[0103] Embodiment 1:

[0104] First stage gasification temperature: 300℃

[0105] One gasification time: 2 hours

[0106] First stage water and organic impurity removal rate: 98%

[0107] Second stage gasification temperature: 2900℃

[0108] Second stage gasification time: 3 hours

[0109] Second stage metal impurity removal rate: 99.9%

[0110] Results: Graphite purity 98%, metal impurity content 0.03%, energy consumption 400kWh, dioxin generation 0.02ng / m 3 .

[0111] Embodiment 2:

[0112] First stage gasification temperature: 350℃

[0113] One gasification time: 2 hours

[0114] First stage water and organic impurity removal rate: 98%

[0115] Second stage gasification temperature: 2900℃

[0116] Second stage gasification time: 3 hours

[0117] Second stage metal impurity removal rate: 99.9%

[0118] Results: Graphite purity 99.2%, metal impurity content 0.01%, energy consumption 375kWh, dioxin generation <0.01ng / m 3 .

[0119] Embodiment 3:

[0120] First stage gasification temperature: 400℃

[0121] One gasification time: 2 hours

[0122] First stage water and organic impurity removal rate: 98%

[0123] Second stage gasification temperature: 2900℃

[0124] Second stage gasification time: 3 hours

[0125] Second stage metal impurity removal rate: 99.9%

[0126] Results: Graphite purity 97.5%, metal impurity content 0.02%, energy consumption 380kWh, dioxin generation 0.01ng / m 3 .

[0127] From Examples 1 to 3, it can be seen that when other parameters are the same, when the primary gasification temperature is 350° C., the graphite purity is the highest, and the metal impurity content, energy consumption and dioxin generation are the lowest.

[0128] Embodiment 4:

[0129] First stage gasification temperature: 350℃

[0130] One gasification time: 1 hour

[0131] First stage water and organic impurity removal rate: 98%

[0132] Second stage gasification temperature: 2900℃

[0133] Second stage gasification time: 3 hours

[0134] Second stage metal impurity removal rate: 99.9%

[0135] Results: Graphite purity 98.5%, metal impurity content 0.015%, energy consumption 370kWh, dioxin generation <0.01ng / m 3 .

[0136] Embodiment 5:

[0137] First stage gasification temperature: 350℃

[0138] One gasification time: 3 hours

[0139] First stage water and organic impurity removal rate: 98%

[0140] Second stage gasification temperature: 2900℃

[0141] Second stage gasification time: 3 hours

[0142] Second stage metal impurity removal rate: 99.9%

[0143] Results: Graphite purity 99%, metal impurity content 0.012%, energy consumption 380kWh, dioxin generation <0.01ng / m 3 .

[0144] From Example 2, Example 4 and Example 5, it can be seen that when other parameters are the same, when the gasification time is 2 hours, the graphite purity is the highest, and the metal impurity content, energy consumption and dioxin generation are the lowest.

[0145] Embodiment 6:

[0146] First stage gasification temperature: 350℃

[0147] One gasification time: 2 hours

[0148] One-stage water and organic impurity removal rate: 95%

[0149] Second stage gasification temperature: 2900℃

[0150] Second stage gasification time: 3 hours

[0151] Second stage metal impurity removal rate: 99.9%

[0152] Results: Graphite purity 98.8%, metal impurity content 0.015%, energy consumption 385kWh, dioxin generation <0.01ng / m 3 .

[0153] Embodiment 7:

[0154] First stage gasification temperature: 350℃

[0155] One gasification time: 2 hours

[0156] First stage water and organic impurity removal rate: 99%

[0157] Second stage gasification temperature: 2900℃

[0158] Second stage gasification time: 3 hours

[0159] Second stage metal impurity removal rate: 99.9%

[0160] Results: Graphite purity 99.2%, metal impurity content 0.01%, energy consumption 375kWh, dioxin generation <0.01ng / m 3 .

[0161] From Example 2, Example 6 and Example 7, it can be concluded that when other parameters are the same, the optimum removal rate of water and organic impurities in the first stage is 98%, which is the best effect.

[0162] Embodiment 8:

[0163] First stage gasification temperature: 350℃

[0164] One gasification time: 2 hours

[0165] First stage water and organic impurity removal rate: 98%

[0166] Second stage gasification temperature: 2800℃

[0167] Second stage gasification time: 3 hours

[0168] Second stage metal impurity removal rate: 99.9%

[0169] Results: Graphite purity 98.7%, metal impurity content 0.02%, energy consumption 370kWh, dioxin generation <0.01ng / m 3 .

[0170] Embodiment 9:

[0171] First stage gasification temperature: 350℃

[0172] One gasification time: 2 hours

[0173] First stage water and organic impurity removal rate: 98%

[0174] Second stage gasification temperature: 3000℃

[0175] Second stage gasification time: 3 hours

[0176] Second stage metal impurity removal rate: 99.9%

[0177] Results: Graphite purity 99.2%, metal impurity content 0.01%, energy consumption 375kWh, dioxin generation <0.01ng / m3 .

[0178] From Example 2, Example 8 and Example 9, it can be concluded that when other parameters are the same, the comprehensive effect is best when the second-stage gasification temperature is 2900°C.

[0179] Embodiment 10:

[0180] First stage gasification temperature: 350℃

[0181] One gasification time: 2 hours

[0182] First stage water and organic impurity removal rate: 98%

[0183] Second stage gasification temperature: 2900℃

[0184] Second stage gasification time: 2 hours

[0185] Second stage metal impurity removal rate: 99.9%

[0186] Results: Graphite purity 98.9%, metal impurity content 0.02%, energy consumption 370kWh, dioxin generation <0.01ng / m 3 .

[0187] Embodiment 11:

[0188] First stage gasification temperature: 350℃

[0189] One gasification time: 2 hours

[0190] First stage water and organic impurity removal rate: 98%

[0191] Second stage gasification temperature: 2900℃

[0192] Second stage gasification time: 4 hours

[0193] Second stage metal impurity removal rate: 99.9%

[0194] Results: Graphite purity 99.3%, metal impurity content 0.01%, energy consumption 380kWh, dioxin generation <0.01ng / m 3 .

[0195] From Example 2, Example 10 and Example 11, it can be seen that when other parameters are the same, the comprehensive effect is best when the second-stage gasification time is 3 hours.

[0196] Embodiment 12:

[0197] First stage gasification temperature: 350℃

[0198] One gasification time: 2 hours

[0199] First stage water and organic impurity removal rate: 98%

[0200] Second stage gasification temperature: 2900℃

[0201] Second stage gasification time: 3 hours

[0202] Second stage metal impurity removal rate: 98%

[0203] Results: Graphite purity 98.5%, metal impurity content 0.02%, energy consumption 375kWh, dioxin generation <0.01ng / m 3 .

[0204] Embodiment 13:

[0205] First stage gasification temperature: 350℃

[0206] One gasification time: 2 hours

[0207] First stage water and organic impurity removal rate: 98%

[0208] Second stage gasification temperature: 2900℃

[0209] Second stage gasification time: 3 hours

[0210] Second stage metal impurity removal rate: 99.99%

[0211] Results: Graphite purity 99.2%, metal impurity content 0.01%, energy consumption 375kWh, dioxin generation <0.01ng / m 3 .

[0212] From Example 2, Example 12 and Example 13, it can be concluded that when other parameters are the same, the best removal rate of metal impurities in the second stage is 99.9%, and the comprehensive effect is the best at this time.

[0213] From Examples 1 to 13, it can be seen that when the optimal process parameters are as follows, the effect of two-stage gasification of graphite is the best:

[0214] First stage gasification temperature: The best effect is achieved at 350℃.

[0215] The best effect is achieved when the vaporization time is 2 hours.

[0216] The first stage removal rate: 98% is the best removal rate.

[0217] Second stage gasification temperature: 2900℃ is the optimal temperature.

[0218] Second stage gasification time: 3 hours for best effect.

[0219] Second stage removal rate: 99.9% is the best removal rate.

[0220] The results of the optimal process parameters are: graphite purity 99.2%, metal impurity content 0.01%, energy consumption 375kWh, dioxin generation <0.01ng / m 3 .

[0221] In summary, the beneficial effects of the present invention are:

[0222] (1) The first gasifier 1, the first heater 3 and the rotatable furnace tube 2 are used to dry the water in the graphite obtained by aeration separation and remove organic impurities to keep the graphite dry. The graphite after the first stage of gasification needs to be cooled by setting a transmission device for cooling to prevent thermal shock when directly entering the high-temperature second stage of gasification. The second gasifier 4 and the second heater 7 are used to further remove excess metal impurities in the graphite, and a secondary graphitization treatment is performed to improve the purity and performance of the graphite.

[0223] (2) Remove moisture and organic impurities at a lower temperature to avoid energy waste and unnecessary complexity of high-temperature treatment. By removing most impurities at a lower temperature first, the time and energy required for high-temperature treatment can be reduced, saving energy and reducing costs. The two-stage gasification process saves about 25% of energy compared to a single high-temperature treatment.

[0224] (3) Organic matter is removed at low temperatures to avoid decomposition at high temperatures to produce harmful gases such as dioxins, thereby reducing air pollution and protecting the environment;

[0225] (4) By gradually increasing the temperature, excessive sintering or other forms of thermal damage to the material can be avoided, thereby improving the quality of the final product; at high temperatures, metal impurities can be completely removed, and high temperature conditions help optimize the crystal structure of graphite, thereby improving its purity and performance;

[0226] (5) Gradually increasing the temperature can reduce the heat load and stress of the equipment, extend the service life of the equipment, and reduce maintenance and replacement costs;

[0227] (6) Staged gasification can better control the reaction process and parameters of each treatment stage, ensuring the stability and controllability of the treatment process, especially in the high-temperature stage, to ensure the best treatment effect. By gradually increasing the temperature in stages, the risk of sudden thermal reactions and equipment failures can be reduced, thereby improving the overall safety of the process.

[0228] The various devices selected in this application are all universal standard parts or parts known to those skilled in the art, and their structures and principles can be known to those skilled in the art through technical manuals or conventional experimental methods.

[0229] In the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0230] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0231] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A two-stage gasification device for graphite regeneration, characterized in that: include: A first-stage gasification device, a transmission device, and a second-stage gasification device are sequentially connected and arranged, wherein the first-stage gasification device comprises a first gasification furnace (1), a furnace tube (2) is rotatably arranged in the first gasification furnace (1), and a graphite mixture to be heated enters from one end of the furnace tube (2), and a first heater (3) is arranged around the inner wall of the first gasification furnace (1), and the first heater (3) is located outside the furnace tube (2); The two-stage gasification equipment comprises a second gasification furnace (4), a heating chamber (5) is provided in the second gasification furnace (4), a furnace door (6) for adding graphite after a first stage of gasification is provided at the upper end of the second gasification furnace (4), and a second heater (7) is provided in the heating chamber (5); One end of the transmission device is connected to the other end of the furnace tube (2), and the other end of the transmission device is arranged above the furnace door (6). After a period of gasification, the graphite is discharged from the other end of the furnace tube (2) and transported to the heating chamber (5) of the second gasification furnace (4) through the transmission device.

2. The two-stage gasification device for graphite regeneration as claimed in claim 1, characterized in that: The one-stage gasification equipment further comprises a driving assembly, a first mounting base (8) and a first feed hopper (9); the driving assembly and the first gasification furnace (1) are both mounted on the first mounting base (8); the upper end of the driving assembly is sleeved on the other end of the furnace tube (2); the driving assembly is used to drive the furnace tube (2) to rotate; and the first feed hopper (9) is arranged on one end of the furnace tube (2).

3. The two-stage gasification device for graphite regeneration as claimed in claim 2, characterized in that: The driving assembly comprises a passive wheel (10) and two driving parts, the two driving parts are respectively arranged on both sides of the passive wheel (10), each of the driving parts comprises a driving wheel (11), a driving motor (12) and a motor mounting seat (13), the passive wheel (10) is sleeved on the other end of the furnace tube (2), the driving wheel (11) is mounted on the moving end of the driving motor (12) and meshes with the passive wheel (10) for transmission, the driving motor (12) is mounted on the motor mounting seat (13), and the motor mounting seat (13) is mounted on the first mounting base (8).

4. The two-stage gasification device for graphite regeneration as claimed in claim 3, characterized in that: The axis of the furnace tube (2) is arranged to be inclined downward in a direction close to the transmission device, the axis of the moving end of the drive motor (12) is arranged parallel to the axis of the furnace tube (2), the rotation direction between the two drive wheels (11) is the same, and the rotation direction between the drive wheel (11) and the driven wheel (10) is opposite.

5. The two-stage gasification device for graphite regeneration as claimed in claim 1, characterized in that: A handle (14) is provided on the furnace door (6) of the second gasification furnace (4).

6. The two-stage gasification device for graphite regeneration as claimed in claim 1, characterized in that: The transmission equipment comprises an intermediate buffer tank (15) and a conveyor (16) connected in sequence, one end of the intermediate buffer tank (15) is connected to the other end of the furnace tube (2) through a first feed pipe, the other end of the intermediate buffer tank (15) is connected to one end of the conveyor (16) through a first discharge pipe, and the other end of the conveyor (16) is arranged above the furnace door (6).

7. The two-stage gasification device for graphite regeneration as claimed in claim 6, characterized in that: The conveyor (16) comprises a support seat (17), a conveying bin (18), a second feed hopper (19), a ventilation pipe (20) and a conveying structure (21). The conveying bin (18) is installed on the support seat (17). A transport passage is provided in the conveying bin (18) from the intermediate buffer tank (15) to the furnace door (6). The conveying structure (21) is arranged in the transport passage for transporting graphite to the second gasification furnace (4). The second feed hopper (19) is arranged on one end of the conveying bin (18). The second feed hopper (19) is connected to the first discharge pipe. A discharge pipe is provided at the lower end of the other end of the conveying bin (18). The discharge pipe is arranged above the furnace door (6). The ventilation pipe (20) is connected from the outside of the conveying bin (18) to the conveying passage.

8. The two-stage gasification device for graphite regeneration as claimed in claim 7, characterized in that: The conveying structure (21) is a conveying belt or a spiral conveying shaft.

9. The two-stage gasification device for graphite regeneration as claimed in claim 1, characterized in that: The first-stage gasification equipment further comprises: a feeding trolley (22), a material transport track (23) and a gasification chamber (24); the first gasification furnace (1) is arranged in the gasification chamber (24); the material transport track (23) is laid from the outside of the gasification chamber (24) to the bottom of one end of the first gasification furnace (1); and the feeding trolley (22) is slidably connected to the material transport track (23).

10. A two-stage gasification process, using the two-stage gasification device for graphite regeneration as described in claims 1 to 9 to remove graphite and metal impurities, characterized in that: The steps include: Step S1, after the graphite mixture to be heated is delivered to one end of the furnace tube (2) by the feeding trolley (22), the empty feeding trolley (22) exits the gasification chamber (24), and the door of the gasification chamber (24) is closed; Step S2, turning on the first heater (3), adjusting the first heater (3) to a heating temperature required for the first stage of gasification through an external temperature control system, setting the first stage of gasification temperature to 300° C. to 400° C., turning on the drive motor (12), driving the furnace tube (2) to rotate through the passive wheel (10) and the drive wheel (11), and setting the first stage of gasification time to 1 hour to 3 hours; Step S3, the graphite obtained in step S2, from which water and organic impurities have been removed, is fed into an intermediate buffer tank (15) through a first feed pipe for cooling; Step S4, the graphite cooled in step S3 enters the conveying bin (18) through the first discharge pipe and the second feed hopper (19), and is conveyed from the discharge pipe to the second gasification furnace (4) through the conveying structure (21). During the conveying, an inert gas is introduced into the conveying bin (18) through the ventilation pipe (20); Step S5, closing the furnace door (6), turning on the second heater (7), adjusting the second heater (7) to the heating temperature required for the second-stage gasification through the external temperature control system, setting the second-stage gasification temperature to 2800° C. to 3000° C., and setting the second-stage gasification time to 2 h to 4 h; Step S6: After the two-stage gasification in step S5, graphite with metal impurities removed is obtained.

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