Carbon micro-powder particle drying, baking and pre-carbonization integrated treatment method
By adopting an integrated continuous processing method, the problems of cumbersome and high cost of existing graphite anode material processes have been solved. This method enables efficient and low-cost drying, baking, and pre-carbonization of carbon microparticles, meeting the requirements of vertical continuous graphitization processes.
Patent Information
- Application Number
- CN202410973912.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-19
- Publication Date
- 2026-01-20
AI Technical Summary
The existing drying, baking and pre-carbonization processes for graphite anode materials are carried out separately, which results in complicated steps, high time and energy consumption, and easy breakage in intermittent processes. This cannot meet the requirements of vertical continuous graphitization processes. At the same time, the existing pre-carbonization furnaces require the introduction of inert gas, which increases costs.
The process adopts an integrated treatment method for drying, baking and pre-carbonizing carbon micropowder particles. The three stages of drying, baking and pre-carbonizing are integrated into a continuous process. Gradual heating is carried out using a mesh belt continuous dryer, a baking machine and a pre-carbonization furnace to avoid material transfer and breakage. Oxygen is isolated by micro-positive pressure and mechanical air sealing.
It enables continuous processing of carbon microparticles, reduces heat waste, reduces labor and time costs, ensures particle integrity and uniformity, improves production efficiency, and reduces equipment and operating costs.
Smart Images
Figure CN121363854A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of battery negative electrode materials, and particularly relates to a carbon powder particle drying, baking and pre-carbonization integrated processing method in the graphitization production of artificial graphite negative electrode materials for batteries. BACKGROUND
[0002] Lithium ion batteries are a kind of secondary batteries. At present, researchers are actively developing lithium ion batteries with better large-current charge and discharge performance and higher safety for use in electric vehicles. Lithium ion batteries have excellent performance in terms of small size, light weight, no pollution, fast charge and discharge, long cycle life and the like. However, the commonly used negative electrode materials include artificial graphite, natural graphite and mesocarbon microbeads, which are essentially graphite-based negative electrode materials. At present, the actual delithiation capacity of graphite-based negative electrode materials in half-batteries has approached the theoretical limit, but still cannot meet the needs of high-energy-density batteries. The common process for graphite-based negative electrode materials is to grind artificial graphite or natural graphite into powder with a particle size meeting the requirements, and then to perform shaping treatment on the powder. In the production process of carbon powder particles, the carbon powder particles are intermediate products at the front end of the vertical continuous graphitization process. Before entering the vertical continuous graphitization process, the carbon powder particles are first dried and the water content is effectively removed to avoid adverse effects in the subsequent process, such as the initiation of side reactions and particle breakage.
[0003] At present, in the existing graphite material process technology, the drying, baking and pre-carbonization processes of carbon powder particles are performed separately. The dried and baked carbon powder particles must be taken out, cooled and then sent to the pre-carbonization equipment for pre-carbonization. This process is complicated, time-consuming, wastes manpower and energy, and also causes the carbon powder particles to break during the intermittent process of transportation, which cannot meet the needs of the vertical continuous graphitization process. In addition, the carbon powder particles are provided with hot-melt thermosetting components. After drying, the carbon powder particles need to be baked to enable the hot-melt thermosetting components to play a good consolidation role.
[0004] In addition, the bottom of the existing pre-carbonization furnace needs to be connected with inert gas to achieve oxygen isolation, which increases the cost of equipment investment and raw materials for production operation.
[0005] Therefore, there is an urgent need for a method for continuous drying, baking and pre-carbonization processing to overcome the above shortcomings and meet the needs of the vertical continuous graphitization process at the back end. SUMMARY
[0006] The present application aims to provide a carbon powder particle drying, baking and pre-carbonization integrated processing method, which integrates the drying, baking and pre-carbonization processes into a continuous process.
[0007] To achieve the above object, the present application provides a carbon micro-powder particle drying, baking and pre-carbonization integrated processing method, which comprises the following steps:
[0008] S1: drying treatment; the carbon micro-powder particles are sent into a net-belt continuous dryer for drying treatment with temperature gradient rising; the dry particles K1 are output from the discharging end of the lowermost net belt, and the moisture content of the dry particles K1 is less than 0.1%;
[0009] S2: baking treatment; the dry particles K1 are directly sent into a baking machine for baking treatment with temperature gradient rising to form carbon micro-powder particles K2, and the moisture content of the carbon micro-powder particles K2 is less than 0.01%;
[0010] S3: pre-carbonization treatment; the carbon micro-powder particles K2 are directly sent into a pre-carbonization furnace for pre-carbonization treatment to form carbon micro-powder pre-carbonization particles K3.
[0011] Preferably, in the carbon micro-powder particle drying, baking and pre-carbonization integrated processing method of the present application, the heat source of the net-belt continuous dryer is obtained by heat exchange, and the temperature of the heat source in the net-belt continuous dryer rises at an equal gradient of 30-105℃ from the uppermost net belt to the lowermost net belt.
[0012] Preferably, in the carbon micro-powder particle drying, baking and pre-carbonization integrated processing method of the present application, a drying tail gas pipe for discharging tail gas is arranged at the top of the net-belt continuous dryer, and the drying tail gas pipe is in communication with a first water pool outside.
[0013] Preferably, in the carbon micro-powder particle drying, baking and pre-carbonization integrated processing method of the present application, the height difference between adjacent net belts is 200-300 mm; if the height difference is too small, i.e. the interlayer gap is too small, the flow of hot air and overflowed water vapor is not smooth, which will affect the drying efficiency, and if the height difference is too large, the particles will be easily damaged when falling.
[0014] Preferably, in the carbon micro-powder particle drying, baking and pre-carbonization integrated processing method of the present application, in the drying treatment, the moving speed of the net belt is 0-20 m / h; the width of the net belt is 1-2 m; and the total distance of the carbon micro-powder particles driven by the whole net belt is 60-120 m.
[0015] Preferably, in the integrated processing method for drying, baking and pre-carbonizing carbon micro-powder particles of the present application, the baking machine has a rotatable drum, the dry particles K1 are transported from the baking inlet to the baking outlet in the baking machine by spiral tumbling rotation of the baking mode, and then the carbon micro-powder particles K2 are formed; a guide groove in a spiral distribution is arranged between the baking inlet and the baking outlet in the drum of the baking machine; the dry particles K1 enter the guide groove from the baking inlet; the dry particles K1 in the guide groove spiral tumble and travel with the rotation of the drum, and then the carbon micro-powder particles K2 are formed by baking to the baking outlet; in the baking process, the rotation speed of the drum is 0.5-3.0 revolutions per minute; the inner diameter of the drum is 1.5-2.0 meters, and the length of the drum is 12-20 meters; the pitch of the guide groove is 100-200 millimeters, and the height of the guide groove is 200-300 millimeters; the temperature of the dry particles K1 from the baking inlet to the baking outlet is gradually increased from 90℃ to 300℃.
[0016] Preferably, in the integrated processing method for drying, baking and pre-carbonizing carbon micro-powder particles of the present application, in the baking process, the baking flue gas is introduced into the heat exchanger of the mesh belt continuous dryer through a pipeline to make the maximum temperature of the bottom of the lowest layer of the mesh belt reach 95-105℃, and the baking flue gas after heat exchange is discharged to the outside second pool through a pipeline.
[0017] Preferably, in the integrated processing method for drying, baking and pre-carbonizing carbon micro-powder particles of the present application, the pre-carbonization furnace is in a vertical structure, the pre-carbonization inlet is located at the top of the pre-carbonization furnace, and the bottom of the pre-carbonization furnace forms a pre-carbonization outlet; a rotating multi-hopper closed gas feeder that can airtightly close the pre-carbonization outlet is arranged in the pre-carbonization outlet; the caliber of the material receiving port of the rotating multi-hopper closed gas feeder is larger than the caliber of the pre-carbonization outlet; the rotating multi-hopper closed gas feeder rotates clockwise; a negative pressure extraction device is arranged at the left middle part of the rotating multi-hopper closed gas feeder to discharge the air in the empty rotating hopper; the pre-carbonization outlet is isolated from the inside of the pre-carbonization furnace and the outside by the rotating multi-hopper closed gas feeder; the rotating multi-hopper closed gas feeder takes out the material that has completed pre-carbonization to obtain the carbon micro-powder pre-carbonization particles K3.
[0018] Preferably, in the integrated drying, baking and pre-carbonization method of the carbon micro-powder particles, the pre-carbonization furnace comprises, from top to bottom, a pre-heating exhaust section, a pre-carbonization section, a heat preservation section, a cooling section and a discharge section, the pre-carbonization inlet is directly communicated with the pre-heating exhaust section, and the pre-carbonization discharge outlet is directly communicated with the discharge section; the temperature of the pre-heating exhaust section increases from 200℃ to 500℃ from top to bottom; the temperature of the pre-carbonization section increases from 500℃ to 1600℃ from top to bottom; the temperature of the heat preservation section decreases from 1600℃ to 600℃ from top to bottom; the temperature of the cooling section decreases from 600℃ to 100℃ from top to bottom; and the temperature of the discharge section decreases from 100℃ to 40℃ from top to bottom.
[0019] Preferably, in the integrated drying, baking and pre-carbonization method of the carbon micro-powder particles, the high-temperature gas overflowing from the pre-carbonization inlet of the pre-carbonization furnace is unidirectionally drained to the net-belt continuous dryer for heat exchange; the pressure of the outlet of the high-temperature gas overflowing from the pre-carbonization inlet is (P0-0)~(P0+30) Pa; wherein P0 is the standard atmospheric pressure value; and the dry particles K1 output from the dropping end of the lowermost net belt are directly conveyed to the baking inlet of the baking machine through the first sealing channel; and the carbon micro-powder particles K2 formed by the baking treatment are directly conveyed to the pre-carbonization inlet of the pre-carbonization furnace through the second sealing channel.
[0020] Preferably, in the integrated drying, baking and pre-carbonization method of the carbon micro-powder particles, the pre-carbonization furnace comprises, from top to bottom, a pre-heating exhaust section, a pre-carbonization section, a heat preservation section, a cooling section and a discharge section, the pre-carbonization inlet is directly communicated with the pre-heating exhaust section, and the pre-carbonization discharge outlet is directly communicated with the discharge section; the temperature of the pre-heating exhaust section increases from 200℃ to 500℃ from top to bottom; the temperature of the pre-carbonization section increases from 500℃ to 1600℃ from top to bottom; the temperature of the heat preservation section decreases from 1600℃ to 600℃ from top to bottom; the temperature of the cooling section decreases from 600℃ to 100℃ from top to bottom; and the temperature of the discharge section decreases from 100℃ to 40℃ from top to bottom.
[0021] Compared with the prior art, the carbon micro-powder particles are transported into the mesh belt type continuous dryer for drying treatment to obtain dry particles K1, the dry particles K1 are directly transported into the drum roaster for roasting treatment to obtain carbon micro-powder particles K2, and the carbon micro-powder particles K2 are directly transported into the pre-carbonization furnace for pre-carbonization treatment to obtain carbon micro-powder pre-carbonization particles K3. As can be seen, the present application realizes continuous drying treatment, roasting treatment and pre-carbonization treatment of the carbon micro-powder particles, integrates the three processes of drying treatment, roasting treatment and pre-carbonization treatment of the carbon micro-powder particles, effectively reduces the waste of heat, reduces the labor cost and time cost caused by material transfer, and avoids the breakage of the carbon micro-powder particles in the existing intermittent process during the transfer process, which cannot meet the feeding requirements of the subsequent vertical continuous graphitization process. At the same time, the carbon micro-powder particles are provided with a hot-melt thermoset component during implementation, and the hot-melt thermoset component in the carbon micro-powder particles can fully play a good consolidation effect after the drying treatment and the roasting treatment, so that the carbon micro-powder pre-carbonization particles K3 obtained by the method of the present application have a more complete appearance and more uniform particles. Specifically, in the drying treatment, the mesh belt type continuous dryer is used for the top-down mesh belt layering layout, and the temperature of the mesh belt is gradiently increased from top to bottom at 30-105 DEG C. On the one hand, the present application can continuously dry the carbon micro-powder particles, ensuring that the subsequent roasting treatment and pre-carbonization treatment can also be continuously carried out, greatly improving the production efficiency. On the other hand, the drying treatment with the mesh belt layering layout and the temperature gradient increase makes the carbon micro-powder particles first undergo a stable temperature drying process for a period of time during the transmission process, so that the carbon micro-powder particles can be fully and uniformly heated, and then the temperature is gradiently increased to jump to another stable temperature for a period of time, accelerating and optimizing the drying process and effect of the carbon micro-powder particles, ensuring that the moisture content of the dry particles K1 formed after the drying treatment is less than 0.1%, avoiding the adverse effects of water in the subsequent process, such as the occurrence of side reactions and particle breakage, and further ensuring that the subsequent roasting treatment can be carried out in an orderly manner.
[0022] Compared with the prior art, the pre-carbonization furnace inlet adopts a micro-positive pressure method for oxygen isolation, and the discharge end adopts a mechanical closed gas method for oxygen isolation, without using inert gas, so that the equipment investment cost and operation cost are reduced to a certain extent. BRIEF DESCRIPTION OF DRAWINGS
[0023] Figure 1 is a hardware equipment layout schematic diagram corresponding to the carbon micro-powder particle drying, roasting and pre-carbonization integrated treatment method of the present application.
[0024] Figure 2 is a structural schematic diagram of the mesh belt type continuous dryer of the present application.
[0025] Figure 3 is a structural schematic diagram of the roaster of the present application.
[0026] Figure 4 is a structural schematic diagram of the layout of the material guide groove in the roller.
[0027] Figure 5 is a structural schematic diagram of the pre-carbonization furnace of the present application.
[0028] Figure 6 is an apparent diagram of the carbon micro-powder pre-carbonization granule K3 product obtained by the carbon micro-powder granule drying, roasting and pre-carbonization integrated processing method according to the present application.
[0029] Figure 7 is an apparent diagram of the carbon micro-powder pre-carbonization granule K3' product obtained by Comparative Example 1.
[0030] Figure 8 is an apparent diagram of the carbon micro-powder pre-carbonization granule K3'' product obtained by Comparative Example 2. DETAILED DESCRIPTION
[0031] Example 1
[0032] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with specific implementation examples and the accompanying drawings, and the technical solutions of the present application will be described and explained. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work belong to the scope of protection of the present application. The specific implementation manners of the present application will be described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be implemented in many other different ways than those described herein, and those skilled in the art can make similar improvements without departing from the concept of the present application, so the present application is not limited to the specific embodiments disclosed below. The embodiments of the present application will now be described with reference to the accompanying drawings, wherein like reference numerals represent like elements.
[0033] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.
[0034] As Figures 1-5 shown, the application carbon micro-powder particle drying, baking and pre-carbonization integrated processing method includes the following three continuous processing steps: S1: drying treatment; S2: baking treatment; S3: pre-carbonization treatment. In combination with Figure 1 shown, wherein the drying treatment is carried out in the mesh belt type continuous dryer 1 provided by the application; the baking treatment is carried out in the baking machine 2 provided by the application; and the pre-carbonization treatment is carried out in the pre-carbonization furnace 3 provided by the application. Specifically, in combination with Figure 1As shown, in implementation, the continuous feeding system is provided to continuously feed the mesh belt continuous dryer 1, which includes a conveying belt 1a and a distributor 1b, the conveying belt 1a is used to convey the carbon powder particles into the mesh belt continuous dryer 1 for drying treatment to the distributor 1b, the distributor 1b continuously receives the carbon powder particles conveyed by the conveying belt 1a and uniformly distributes them to the drying feeding port 10 of the mesh belt continuous dryer 1, so that the carbon powder particles are transported into the mesh belt continuous dryer 1 for drying treatment to obtain dry particles K1. The drying discharge port 11 of the mesh belt continuous dryer 1 is directly communicated with the baking feeding port 20 of the baking machine 2 through the first conveying device 4, which can be a belt conveying device sealed in a housing; the dry particles K1 obtained by the drying treatment of the mesh belt continuous dryer 1 are directly conveyed to the baking feeding port 20 of the baking machine 2 through the first conveying device 4, so that the dry particles K1 directly enter the baking machine 2 for baking treatment, and the dry particles K1 are conveyed out of the baking machine 2 as powder particles K2 after baking treatment in the baking machine 2. The baking discharge port 21 of the baking machine 2 is communicated with the pre-carbonization feeding port 30 of the pre-carbonization furnace 3 through the bucket elevator 5, which can be a bucket elevator with a sealed pipeline for conveying particles; the powder particles K2 conveyed out of the baking discharge port 21 of the baking machine 2 are conveyed to the pre-carbonization feeding port 30 of the pre-carbonization furnace 3 under the transmission action of the bucket elevator 5, so that the powder particles K2 enter the pre-carbonization furnace 3 for pre-carbonization treatment, and the powder particles K2 are conveyed out of the pre-carbonization furnace 3 as carbon powder pre-carbonization particles K3 after pre-carbonization treatment in the pre-carbonization furnace 3. The carbon powder particles are conveyed into the mesh belt continuous dryer for drying treatment to obtain dry particles K1, the dry particles K1 are directly conveyed to the baking machine for baking treatment to obtain carbon powder particles K2, and the carbon powder particles K2 are directly conveyed to the pre-carbonization furnace for pre-carbonization treatment to obtain carbon powder pre-carbonization particles K3. Therefore, the carbon powder particles are conveyed into the mesh belt continuous dryer 1 for drying treatment to obtain dry particles K1, the dry particles K1 are directly conveyed to the baking machine 2 for baking treatment to obtain carbon powder particles K2, and the carbon powder particles K2 are directly conveyed to the pre-carbonization furnace 3 for pre-carbonization treatment to obtain carbon powder pre-carbonization particles K3; the drying treatment, baking treatment and pre-carbonization treatment of the carbon powder particles are integrated and continuously processed, which effectively reduces the waste of heat, reduces the labor cost and time cost caused by material transfer, and avoids the breakage of the carbon powder particles during the transfer process in the existing intermittent process, which cannot meet the feeding requirements of the subsequent vertical continuous graphitization process.
[0035] Continuing to combine Figure 1S1: drying treatment; the carbon micro-powder particles are sent into the net-belt continuous dryer 1 for drying treatment with temperature gradient rising; wherein, the net-belt continuous dryer 1 comprises a net-belt 12 for carrying and conveying the carbon micro-powder particles and a net-belt driving mechanism 13 for driving the net-belt 12 to rotate. Specifically, the net-belt driving mechanism 13 of the present application adopts the existing variable frequency transmission technology, the net-belt 12 is in the shape of a ring, the net-belt 12 is arranged in multiple layers from top to bottom and in parallel, and the rotation directions of the adjacent two net-belts 12 are opposite; the carbon micro-powder particles on the upper layer of the net-belt 12 are conveyed to the discharging end under the rotation of the net-belt 12 and fall into the feeding end of the next lower layer of the net-belt 12 by their own gravity; the temperature of the net-belt 12 from top to bottom rises in gradient from 30 to 105℃; the dry particles K1 are output from the discharging end of the lowermost layer of the net-belt 12, and the moisture content of the dry particles K1 is less than 0.1%. S2: baking treatment; the dry particles K1 are directly conveyed to the baking machine for baking treatment with temperature gradient rising to form carbon micro-powder particles K2, and the moisture content of the carbon micro-powder particles K2 is less than 0.01%. S3: pre-carbonization treatment; the carbon micro-powder particles K2 are directly conveyed to the pre-carbonization furnace for pre-carbonization treatment to form carbon micro-powder pre-carbonization particles K3. As can be seen from the above, the carbon micro-powder particles are conveyed into the net-belt continuous dryer for drying treatment to obtain dry particles K1, the dry particles K1 are directly conveyed to the baking machine for baking treatment to obtain carbon micro-powder particles K2, and the carbon micro-powder particles K2 are directly conveyed to the pre-carbonization furnace for pre-carbonization treatment to obtain carbon micro-powder pre-carbonization particles K3. Therefore, the present application realizes continuous drying treatment, baking treatment and pre-carbonization treatment of carbon micro-powder particles, and integrates the three processes of drying treatment, baking treatment and pre-carbonization treatment of carbon micro-powder particles, which effectively reduces the waste of heat, reduces the labor cost and time cost caused by material transfer, and avoids the breakage of carbon micro-powder particles during the transfer process in the existing intermittent process, which cannot meet the feeding requirements of the subsequent vertical continuous graphitization process. At the same time, the carbon micro-powder particles are provided with hot-melt thermosetting components during the implementation of the present application, and the hot-melt thermosetting components in the carbon micro-powder particles can fully play a good solidification effect after drying treatment and direct baking treatment, so that the carbon micro-powder pre-carbonization particles K3 obtained by the method of the present application have a more complete appearance (as shown in Figure 6As shown), the particles are more uniform. Specifically, in the drying process, the present invention adopts a layered layout of the mesh belt 12 from top to bottom in a continuous mesh belt dryer 1, and a treatment method in which the temperature of the mesh belt 12 gradually increases from top to bottom from 30 to 105°C. On the one hand, this invention can continuously dry the carbon micropowder particles, ensuring that the subsequent baking and pre-carbonization processes can also be carried out continuously, greatly improving production efficiency. On the other hand, the layered layout of the mesh belt 12 and the temperature gradient drying process allow the carbon micropowder particles to undergo a period of stable temperature drying during the transport process, ensuring that the carbon micropowder particles are fully and uniformly heated. Then, the temperature is gradually increased to another stable temperature for a period of time, accelerating and optimizing the drying process and effect of the carbon micropowder particles. This ensures that the moisture content of the dried particles K1 formed after the drying process is less than 0.1%, avoiding the adverse effects of moisture in subsequent processes, such as causing side reactions and particle breakage, and further ensuring that the subsequent baking process can be carried out in an orderly manner.
[0036] Preferably, the mesh belt 12 of the present invention is arranged in six layers from top to bottom. (For ease of description...) Figure 1 Different layers of mesh belts 12 and corresponding drive mechanisms 13; therefore, in Figure 2 The mesh belt and its corresponding drive mechanism are represented by different designations and names, as follows: Figure 1 The six-layer mesh belt 12 and its corresponding drive mechanism 13, in Figure 2 From top to bottom, the mesh belts are designated as follows: first mesh belt 12-1, second mesh belt 12-2, third mesh belt 12-3, fourth mesh belt 12-4, fifth mesh belt 12-5, and sixth mesh belt 12-6. The first mesh belt drive mechanism 13-1 drives the first mesh belt 12-1 to rotate; the second mesh belt drive mechanism 13-2 drives the second mesh belt 12-2 to rotate; the third mesh belt drive mechanism 13-3 drives the third mesh belt 12-3 to rotate; the fourth mesh belt drive mechanism 13-4 drives the fourth mesh belt 12-4 to rotate; the fifth mesh belt drive mechanism 13-5 drives the fifth mesh belt 12-5 to rotate; and the sixth mesh belt drive mechanism 13-6 drives the sixth mesh belt 12-6 to rotate. Because the mesh belts of this invention are ring-shaped, they will rotate cyclically under the drive of the corresponding mesh belt drive mechanisms; therefore, one end of the space region containing the ring shape forms the feed end, and the other end forms the discharge end.
[0037] Combination Figures 1-5 As shown, a preferred embodiment of the integrated processing method for drying, baking, and pre-carbonizing carbon micropowder particles of the present invention is as follows:
[0038] S1: Drying treatment. Specifically, the pressed carbon micro powder particles are conveyed to the distributor 1b by the conveyor belt 1a. The distributor 1b evenly distributes the carbon micro powder particles onto the feed end a of the first mesh belt 12-1. The first mesh belt 12-1 rotates under the drive of the first mesh belt drive mechanism 13-1, causing the carbon micro powder particles carried on it to move along... Figure 2 The carbon microparticles move in the V1 direction to the discharge end b. As the first mesh belt 12-1 continues to rotate, the carbon microparticles at discharge end b will fall onto the feed end c corresponding to the second mesh belt 12-2 directly below under their own gravity. The second mesh belt 12-2 rotates under the drive of the second mesh belt drive mechanism 13-2, causing the carbon microparticles carried on it to move along... Figure 2 The carbon microparticles move in the V2 direction to the discharge end d. As the second mesh belt 12-2 continues to rotate, the carbon microparticles at discharge end d will fall onto the feed end e corresponding to the third mesh belt 12-3 directly below under their own gravity. The third mesh belt 12-3 rotates under the drive of the third mesh belt drive mechanism 13-3, causing the carbon microparticles carried on it to move along... Figure 2 The carbon microparticles move in the V1 direction to the discharge end f. As the third mesh belt 12-3 continues to rotate, the carbon microparticles at discharge end f will fall onto the feed end g of the fourth mesh belt 12-4 directly below under their own gravity. The fourth mesh belt 12-4 rotates under the drive of the fourth mesh belt drive mechanism 13-4, causing the carbon microparticles carried on it to move along... Figure 2 The carbon microparticles move in the V2 direction to the discharge end h. As the fourth mesh belt 12-4 continues to rotate, the carbon microparticles at discharge end h will fall onto the feed end i corresponding to the fifth mesh belt 12-5 directly below under their own gravity. The fifth mesh belt 12-5 rotates under the drive of the fifth mesh belt drive mechanism 13-5, causing the carbon microparticles carried on it to move along... Figure 2 The carbon microparticles move in the V1 direction to the discharge end j. As the fifth mesh belt 12-5 continues to rotate, the carbon microparticles at discharge end j will fall onto the feed end k corresponding to the sixth mesh belt 12-6 directly below, under their own gravity. The sixth mesh belt 12-6 rotates under the drive of the sixth mesh belt drive mechanism 13-6, causing the carbon microparticles carried on it to move along... Figure 2 The carbon microparticles move in the V2 direction to the discharge end m. As the sixth mesh belt 12-6 continues to rotate, the carbon microparticles at discharge end m will fall onto the first conveying device 4 directly below under their own gravity. The carbon microparticles falling from discharge end m are the dry particles K1 with a moisture content of less than 0.1% according to this invention. It is worth noting that... Figure 2The V1 direction and the V2 direction are opposite directions, the feeding end a forms a drying feeding port 10 of the mesh belt continuous dryer 1, and the discharging end m forms a drying discharging port 11 of the mesh belt continuous dryer 1.
[0039] Continuing to combine Figures 1-5 As shown, further, in the S1: drying treatment step, the heat source of the mesh belt continuous dryer 1 of the present application is obtained through heat exchange from the bottom to the top of the circulation flow in the mesh belt continuous dryer 1; specifically, but not limited to, through existing ways of generating heat sources such as natural gas combustion heating, electric heating wire heating, and heat energy exchange; the heat source generated by these ways is exchanged with the bottom 14a of the box body 14 of the mesh belt continuous dryer 1, so that the bottom 14a of the box body 14 of the mesh belt continuous dryer 1 generates hot air with the highest temperature; the fan unit 15 for upward blowing is arranged at the bottom 14a of the mesh belt continuous dryer 1, and the high-temperature hot air of the bottom 14a circulates from bottom to top under the blowing action of the fan unit 15, and transfers heat to the carbon micro-powder particles to be dried on each layer of the mesh belt. Since the temperature of the bottom 14a is the highest, and the mesh belts 12 between each layer have a height difference, the temperature between each layer of the mesh belts 12 presents a gradient difference.
[0040] Continuing to combine Figure 1 - Figure 5 As shown, specifically, the temperature of the heat source in the mesh belt continuous dryer 1 from the mesh belt at the lowest layer to the mesh belt at the highest layer presents an equal gradient decrease from 105 to 30°C, that is, the temperature of the heat source in the mesh belt continuous dryer 1 from the mesh belt at the highest layer to the mesh belt at the lowest layer presents an equal gradient increase from 30 to 105°C. Specifically, in the above-mentioned embodiment of six layers of mesh belts 12, the temperature of the sixth mesh belt 12-6 is 105°C; the temperature of the fifth mesh belt 12-5 is 90°C; the temperature of the fourth mesh belt 12-4 is 75°C; the temperature of the third mesh belt 12-3 is 60°C; the temperature of the second mesh belt 12-2 is 45°C; and the temperature of the first mesh belt 12-1 is 30°C. Preferably, the temperature of the heat source in the mesh belt continuous dryer 1 from the mesh belt at the lowest layer to the mesh belt at the highest layer presents an equal gradient decrease from 105 to 45°C, that is, the temperature of the heat source in the mesh belt continuous dryer 1 from the mesh belt at the highest layer to the mesh belt at the lowest layer presents an equal gradient increase from 45 to 105°C. Specifically, in the above-mentioned embodiment of six layers of mesh belts 12, the temperature of the sixth mesh belt 12-6 is 105°C; the temperature of the fifth mesh belt 12-5 is 93°C; the temperature of the fourth mesh belt 12-4 is 81°C; the temperature of the third mesh belt 12-3 is 69°C; the temperature of the second mesh belt 12-2 is 57°C; and the temperature of the first mesh belt 12-1 is 45°C.
[0041] Preferably, the temperature gradient between two adjacent said mesh belts 12 of the present application is 12-15℃. The height difference between adjacent mesh belts 12 is 200-300mm; if the height difference is too small, i.e. the gap between layers is too small, the flow of hot air and the overflow of water vapor is not smooth, which will affect the drying efficiency, and if the height difference is too large, it will easily lead to the breakage of particles when falling.
[0042] Preferably, the height difference between the outlet of the present application and the drying inlet 10 is 260mm; the height difference between adjacent mesh belts 12 of the present application is 260mm; the moving speed of the mesh belt 12 of the present application is 0-20m / h; the width of the mesh belt 12 is 1-2m; the total distance traveled by the carbon micro-powder particles driven by all the mesh belts is 60-120m. Further, the moving speed and rotation direction of the mesh belt 12 are controlled by the corresponding mesh belt driving mechanism 13, and the moving speed of all mesh belts 12 at the same time is the same. More specifically, the height difference between adjacent mesh belts 12 of the present application is equal to 260mm; the moving speed of the mesh belt 12 of the present application is 20m / h; the width of the mesh belt 12 of the present application is 2m; the total distance traveled by the carbon micro-powder particles driven by all the mesh belts 12 of the present application is 60m; and the drying treatment time of the present application is 3h.
[0043] Preferably, the present application is provided with a drying tail gas pipe 15 at the top of the mesh belt continuous dryer 1 for discharging tail gas, which is in communication with the first water pool 16. The drying tail gas pipe 15 is used to discharge the high water content tail gas in the mesh belt continuous dryer 1, which is connected to the first water pool 16 to absorb the smoke and recover fine dust, and the recovered fine dust can be used in the granulation process of carbon micro-powder in the front-end process, thereby saving cost and preventing environmental pollution.
[0044] In combination Figure 1 - Figure 5As shown, S2: baking treatment; dry particles K1 with moisture content less than 0.1% dropped from the blanking end m are directly conveyed into the baking inlet 20 of the baking machine 2 through the first sealed channel; preferably, the first sealed channel is provided by the first conveying device 4, which provides the first sealed channel to convey the dry particles K1 into the baking inlet 20, which can effectively avoid the dry particles K1 exposed in the conveying process. Specifically, the dry particles K1 entering the baking inlet 20 are conveyed to the baking outlet 21 in the baking machine 2 by the spiral tumbling rotation baking mode, and the dry particles K1 are subjected to the baking treatment with the temperature gradient increasing in the baking machine 2, and the temperature increasing trend is the same as the travel trend of the dry particles K1 spirally tumbling in the baking machine 2, that is, the farther the dry particles K1 travel in the baking machine 2, the higher the temperature. Finally, the carbon powder particles K2 with moisture content less than 0.01% are conveyed out from the baking outlet 21. More specifically, in order to better realize the spiral tumbling rotation baking of the dry particles K1 in the baking machine 2, the baking machine 2 of the present application has an additional drum structure, and the baking machine 2 has a self-rotating drum 22. The self-rotation of the drum 22 is driven by a drum driving mechanism 22a. The drum driving mechanism 22a can be realized by using the existing variable frequency transmission technology. The drum 22 of the baking machine 2 is provided with a guide groove 23 spirally distributed between the baking inlet 20 and the baking outlet 21, Figure 4 A structural diagram of the guide groove 23 spirally distributed in the drum 22 is shown.
[0045] Continuing to combine Figure 1 Figure 5 As shown, further, in the S2: baking treatment step, the dry particles K1 directly enter the guide groove 23 from the baking inlet 20, and the dry particles K1 spirally tumble in the guide groove 23 and travel to the baking outlet 21 to form the carbon powder particles K2 with moisture content less than 0.01% by the self-rotation of the drum 22. The dry particles K1 of the present application are subjected to the baking treatment with the temperature gradient increasing from the baking inlet 20 to the baking outlet 21; specifically, the temperature of the dry particles K1 from the baking inlet 20 to the baking outlet 20 is gradiently increased to 90-300°C. The baking machine 2 obtains heat source by external heating, and the heat source obtaining mode includes but is not limited to natural gas combustion heating, electric heating wire heating and heat energy exchange and other existing heat source generating modes. The self-rotation speed of the drum 22 of the present application is 0.5-3.0 revolutions per minute; the inner diameter of the drum 22 of the present application is 1.5-2.0 meters, and the length of the drum 22 of the present application is 12-20 meters; the pitch of the guide groove 23 of the present application is 100-200 millimeters, and the height of the guide groove 23 of the present application is 200-300 millimeters; the baking treatment time of the present application is 0.5-2.0 hours.
[0046] Preferably, the self-rotation speed of the drum 22 of the present application is 1.5 revolutions per minute; the inner diameter of the drum 22 of the present application is 1.5 meters, the length of the drum 22 of the present application is 12 meters; the pitch of the material guide groove 23 of the present application is 120 millimeters, the height of the material guide groove 23 of the present application is 230 millimeters; the time of the baking process of the present application is 1.0 hour.
[0047] Preferably, in order to facilitate the transmission of the dry particles K1 in the baking machine 2, the position of the baking feeding port 20 of the present application is higher than the position of the baking discharging port 21.
[0048] Preferably, in the baking process of the present application, the baking flue gas is opposite to the direction of travel of the dry particles K1, and the baking flue gas is discharged to the outside second pool 25 through the pipeline 24; more specifically, in order to integrate the utilization of resources, the above-mentioned first pool 16 and the second pool 25 can be the same pool. The pipeline 24 is used to discharge the baking flue gas in the baking machine 2, which is connected to the second pool 25 to absorb the flue gas and can recover the fine dust, which can be used in the granulation process of the carbon fine powder in the front-end process, thereby saving costs and preventing environmental pollution.
[0049] Preferably, the present application is also provided with a cyclone dust collector 6, which is in communication with the drying tail gas pipe 15 and the pipeline 24, for recovering fine dust in the drying tail gas and the baking flue gas. The fine dust collected by the cyclone dust collector 6 can be more conveniently used in the granulation process of the carbon fine powder in the front-end process.
[0050] In combination Figures 1-5As shown, S3: pre-carbonization treatment; the carbon powder particles K2 with a water content less than 0.01% delivered from the roasting discharge port 21 of the roaster 2 are directly delivered to the pre-carbonization inlet port 30 of the pre-carbonization furnace 3 through a second sealed channel; preferably, the second sealed channel is provided by the bucket elevator 5, and the transmission of the carbon powder particles K2 to the pre-carbonization inlet port 30 by the second sealed channel can effectively avoid the exposure of the carbon powder particles K2 during the transmission process. In the implementation, the second sealed channel provided by the bucket elevator 5 directly delivers the carbon powder particles K2 to the pre-carbonization inlet port 30 of the pre-carbonization furnace 3, so that the powder particles K2 enter the pre-carbonization furnace 3 for pre-carbonization treatment, and the powder particles K2 after the pre-carbonization treatment in the pre-carbonization furnace 3 are delivered from the pre-carbonization discharge port 31 to obtain the carbon powder pre-carbonization particles K3 with a more complete appearance and more uniform particles. Specifically, the pre-carbonization furnace 3 of the present application has a vertical structure, the pre-carbonization inlet port 30 is located at the top of the pre-carbonization furnace 3, and the bottom of the pre-carbonization furnace 3 forms the pre-carbonization discharge port 31. In order to control the pre-carbonization time and the discharge speed and prevent air from entering the pre-carbonization furnace 3 from the pre-carbonization discharge port 31, the present application is provided with a rotating multi-bucket closed gas feeder 32 in the pre-carbonization discharge port 31, which can airtightly close the pre-carbonization discharge port 31; when the rotating multi-bucket closed gas feeder 32 closes the pre-carbonization discharge port 31, the pre-carbonization discharge port 31 is isolated from the outside; when the closed gas feeder opens the pre-carbonization discharge port 31, the pre-carbonization discharge port 31 drops the pre-carbonization completed material, i.e. the carbon powder pre-carbonization particles K3 with a more complete appearance and more uniform particles are dropped from the pre-carbonization discharge port 31; the rotating multi-bucket closed gas feeder 32 can use the existing open-close door mechanism, which has a door body that can be opened and closed and a driving structure that drives the door body to be opened and closed. More specifically, the rotating bucket of the rotating multi-bucket closed gas feeder 32 is provided with 4-8 buckets; the diameter of the receiving port of the rotating multi-bucket closed gas feeder is greater than the diameter of the pre-carbonization discharge port 31; the rotating multi-bucket closed gas feeder 32 of the present application rotates clockwise; a negative pressure device is provided at the left middle part of the rotating multi-bucket closed gas feeder 32, which is used to exhaust the air in the rotating multi-bucket closed gas feeder that is empty; when the rotating multi-bucket closed gas feeder 32 is closed or opened, the pre-carbonization discharge port 31 is isolated from the inside of the pre-carbonization furnace 3 and directly communicates with the outside, so that the outside air can be effectively prevented from entering (mainly to prevent oxygen in the air from entering, because the entry of oxygen will have a negative impact on the carbon powder particles: C+O2=CO2 or C+H2O=CO+H2); the rotating bucket takes out the pre-carbonization completed material to obtain the carbon powder pre-carbonization particles K3. It can be seen that the furnace bottom of the pre-carbonization treatment process of the present application adopts mechanical airtight oxygen isolation, which effectively reduces the waste of heat and material.
[0051] Continue to combine Figures 1-5As shown, further, in the S3: pre-carbonization treatment step, the pre-carbonization furnace of the present application comprises, from top to bottom, a preheating exhaust section 3a, a pre-carbonization section 3b, a heat preservation section 3c, a cooling section 3d and a discharge section 3e, the pre-carbonization feeding port 30 is directly communicated with the preheating exhaust section 3a, the pre-carbonization discharge port 31 is not communicated with the discharge section 3e and is separated by the rotary multi-bucket closed-air discharger 32, regardless of whether the rotary multi-bucket closed-air discharger 32 is in a stop state or a rotating state. Specifically, the pre-carbonization feeding port 30 can be understood as an upper opening of the preheating exhaust section 3a; the pre-carbonization discharge port 31 and the discharge port of the discharge section 3e constitute closed-air discharging through the bucket of the rotary multi-bucket closed-air discharger 32 arranged above, that is, the material in the discharge section 3e is taken out by the bucket of the rotary multi-bucket closed-air discharger 32 in a closed-air state, thereby completing the discharging. Further, the temperature of the preheating exhaust section 3a of the present application increases from 200°C to 500°C from top to bottom; the temperature of the pre-carbonization section 3b of the present application increases from 500°C to 1600°C from top to bottom; the temperature of the heat preservation section 3c of the present application decreases from 1600°C to 600°C from top to bottom; the temperature of the cooling section 3d of the present application decreases from 600°C to 100°C from top to bottom; the temperature of the discharge section 3e of the present application decreases from 100°C to 40°C from top to bottom; the pre-carbonization treatment time of the present application is 2-10 hours.
[0052] Preferably, the high-temperature gas overflowing from the pre-carbonization feeding port 30 of the pre-carbonization furnace 3 of the present application is unidirectionally introduced to the mesh-belt continuous drying machine 1 for heat exchange. Specifically, the high-temperature gas overflowing from the pre-carbonization furnace 3 is transported to the mesh-belt continuous drying machine 1 through the conveying pipeline 33 and the air induction fan arranged on the conveying pipeline 33 for blowing, so that the high-temperature gas overflowing from the pre-carbonization furnace 3 can only move towards the mesh-belt continuous drying machine 1 (i.e., the high-temperature gas is unidirectionally introduced to the mesh-belt continuous drying machine 1). By unidirectionally introducing the high-temperature gas overflowing from the pre-carbonization feeding port 30 to the mesh-belt continuous drying machine 1 for heat exchange, the present application effectively reduces the energy consumption of the mesh-belt continuous drying machine 1, and the air induction fan is arranged as a variable frequency fan. More specifically, the pressure of the outlet of the high-temperature gas overflowing from the pre-carbonization feeding port 30 of the present application is (P0-0)~(P0+30) Pa; wherein P0 is the standard atmospheric pressure value; controlling the outlet pressure within this range not only ensures the unidirectional flow of the overflowing high-temperature gas towards the mesh-belt continuous drying machine 1, but also effectively avoids excessive negative pressure which is not conducive to oxygen isolation in the pre-carbonization furnace 3, and effectively avoids excessive positive pressure which is not conducive to the overflow of the high-temperature gas generated in the pre-carbonization furnace 3.
[0053] The carbon micro-powder pre-carbonization particles K3 produced according to the above-mentioned embodiments of the present application (see detailed description below) Figure 6 As shown, the appearance is complete and can meet the needs of the subsequent vertical continuous graphitization process.
[0054] Comparative Example 1:
[0055] On the basis of the integrated processing method for drying, baking and pre-carbonizing carbon micro-powder particles of the present application, the S1: drying treatment step is omitted (i.e., the use of the net-belt type continuous dryer 1 is skipped), while the water content of the micro-powder particles K2 output after the baking treatment is less than 0.01%, and the rest of any hardware equipment, process parameters, environmental factors, etc. remain unchanged, the product delivered by the pre-carbonization discharge port of the final pre-carbonization furnace is the carbon micro-powder pre-carbonized particles K3' which have a relatively serious breakage and pulverization phenomenon, and the carbon micro-powder pre-carbonized particles K3' product is shown in detail in Figure 7 .
[0056] On the basis of the integrated processing method for drying, baking and pre-carbonizing carbon micro-powder particles of the present application, the S2: baking treatment step is omitted (i.e., the use of the baking machine 2 is skipped), while the water content of the dry particles K1 output after the drying treatment is less than 0.1%, and the rest of any hardware equipment, process parameters, environmental factors, etc. remain unchanged, the product delivered by the pre-carbonization discharge port of the final pre-carbonization furnace is the carbon micro-powder pre-carbonized particles K3'' which have a relatively serious breakage and pulverization phenomenon, and the carbon micro-powder pre-carbonized particles K3'' product is shown in detail in Figure 8 .
[0057] It is apparent to those skilled in the art that the present application is not limited to the details of the foregoing exemplary embodiments, and that the present application can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be considered in all respects as illustrative and not restrictive, the scope of the present application being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference signs in the claims should not be construed as limiting the claims. While the foregoing is directed to embodiments of the present application, other and further embodiments can be devised without departing from the basic scope of the application. Accordingly, the scope of the present application should be determined with reference to the appended claims.
Claims
1. A method for drying, baking and pre-carbonizing carbon micro-powder particles, characterized in that, It comprises the following steps: S1: drying treatment; carbon powder particles are sent into a net belt type continuous dryer for drying treatment with temperature gradient rising; the falling end of the lowest layer of net belt outputs dry particles K1, the moisture content of the dry particles K1 is less than 0.1%; S2: baking treatment; the dry particles K1 are directly transported into a baking machine for baking treatment with temperature gradient rising to form carbon powder particles K2, the moisture content of the carbon powder particles K2 is less than 0.01%; S3: pre-carbonization treatment; the carbon powder particles K2 are directly transported into a pre-carbonization furnace for pre-carbonization treatment to form carbon powder pre-carbonization particles K3.
2. The integrated drying, torrefying and pre-carbonizing method of carbon fines particles as claimed in claim 1, wherein, The heat source of the net belt type continuous dryer is obtained through heat exchange, and the temperature of the heat source in the net belt type continuous dryer rises at an equal gradient of 30-105℃ from the uppermost layer of net belt to the lowest layer of net belt.
3. The integrated drying, torrefying and pre-carbonizing method of carbon fines particles as claimed in claim 1, wherein, The top of the net belt type continuous dryer is provided with a drying tail gas pipe for discharging tail gas, and the drying tail gas pipe is in communication with a first water pool outside.
4. The integrated drying, torrefying and pre-carbonizing method of carbon fines particles as claimed in claim 1, wherein, The height difference between adjacent net belts is 200-300 mm.
5. The integrated drying, torrefying and pre-carbonizing method of carbon fines particles as claimed in claim 1, wherein, In the drying treatment, the moving speed of the net belt is 0-20 m / h, the width of the net belt is 1-2 m, and the total distance of the carbon powder particles driven by the whole net belt is 60-120 m.
6. The integrated drying, torrefying and pre-carbonizing method of carbon fines particles as claimed in claim 1, wherein, The baking machine has a rotatable roller, the dry particles K1 are transported from a baking inlet to a baking outlet in the baking machine through spiral rolling rotation of the baking machine, and then the carbon powder particles K2 are formed; a guide groove is spirally arranged in the roller of the baking machine between the baking inlet and the baking outlet; the dry particles K1 enter the guide groove from the baking inlet, the dry particles K1 in the guide groove spirally roll and travel with the rotation of the roller, and then the dry particles K1 are baked to the baking outlet to form the carbon powder particles K2; in the baking treatment, the rotation speed of the roller is 0.5-3.0 revolutions per minute, the inner diameter of the roller is 1.5-2.0 m, the length of the roller is 12-20 m, the pitch of the guide groove is 100-200 mm, the height of the guide groove is 200-300 mm, and the temperature of the dry particles K1 from the baking inlet to the baking outlet rises at a gradient of 90-300℃.
7. The integrated drying, torrefying and pre-carbonizing process of carbon fines particles as claimed in claim 1, wherein, In the baking treatment, baking flue gas is introduced into the heat exchanger of the net belt type continuous dryer through a pipeline to make the highest temperature of the bottom of the lowest layer of net belt reach 95-105℃, and the baking flue gas after heat exchange is discharged to a second water pool outside through a pipeline.
8. The integrated drying, torrefying and pre-carbonizing method of carbon fines particles as claimed in claim 1, wherein, The pre-carbonization furnace has a vertical structure, the pre-carbonization inlet is located at the top of the pre-carbonization furnace, and the bottom of the pre-carbonization furnace forms a pre-carbonization outlet; a rotating multi-hopper closed gas feeder capable of airtightly closing the pre-carbonization outlet is arranged in the pre-carbonization outlet; the diameter of the receiving port of the rotating multi-hopper closed gas feeder is larger than that of the pre-carbonization outlet; the rotating multi-hopper closed gas feeder rotates clockwise; a negative pressure extraction device is arranged at the left middle part of the rotating multi-hopper closed gas feeder to discharge air in the rotating hopper. The pre-carbonization outlet is isolated from the inside of the pre-carbonization furnace and the outside by the rotary multi-bucket closed gas feeder, and the rotary multi-bucket closed gas feeder takes out the material after pre-carbonization to obtain the carbon micro-powder pre-carbonization particles K3.
9. The integrated drying, torrefying and pre-carbonizing process of carbon fines particles as claimed in claim 1, wherein, The pre-carbonization furnace comprises, from top to bottom, a preheating exhaust section, a pre-carbonization section, a heat preservation section, a cooling section and a discharge section, the pre-carbonization inlet is directly communicated with the preheating exhaust section, and the pre-carbonization outlet is directly communicated with the discharge section; the temperature of the preheating exhaust section increases from 200℃ to 500℃ from top to bottom; the temperature of the pre-carbonization section increases from 500℃ to 1600℃ from top to bottom; the temperature of the heat preservation section decreases from 1600℃ to 600℃ from top to bottom; the temperature of the cooling section decreases from 600℃ to 100℃ from top to bottom; and the temperature of the discharge section decreases from 100℃ to 40℃ from top to bottom.
10. The integrated drying, torrefying and pre-carbonizing method of carbon fines particles as claimed in claim 1, wherein, The high-temperature gas overflowing from the pre-carbonization inlet of the pre-carbonization furnace is unidirectionally introduced to the mesh belt continuous dryer for heat exchange; the pressure of the outlet of the high-temperature gas overflowing from the pre-carbonization inlet is (P0-0)~(P0+30) Pa; Wherein, P0 is the standard atmospheric pressure value; the dry particles K1 output from the dropping end of the lowest mesh belt are directly conveyed to the baking inlet of the baking machine through the first sealing channel; and the carbon micro-powder particles K2 formed by the baking treatment are directly conveyed to the pre-carbonization inlet of the pre-carbonization furnace through the second sealing channel.