Roller hearth furnace for sintering hard carbon anode for sodium ion batteries

Abstract

The present invention discloses a roller furnace for sintering hard carbon negative electrodes of sodium ion batteries, comprising a roller furnace body, the starting section and the ending section of the roller furnace body are respectively provided with a purification mechanism and an active impurity removal mechanism; the active impurity removal mechanism comprises a discharge stage and a dust collecting stage, the discharge stage comprises a plurality of horizontal and equidistantly arranged pole plates, and the arrangement direction of the pole plates is parallel to the direction of material travel, the dust collecting stage is vertically arranged at the top of the discharge stage and its width matches the width of the furnace chamber of the roller furnace body, the cavity of the dust collecting stage is vertically connected and the horizontal cross section is honeycomb-shaped, and a second gas collecting hopper is arranged at the top of the dust collecting stage; the air purified by the purification mechanism output by the gas transmission pipe is uniformly blown to the outer surface of the material after being pressurized by the dust collecting stage and diverted by the discharge stage. The present invention can not only remove dust and purify the air in the starting section of the roller furnace body and the hard carbon surface, but also clean the oxides and carbonization reactants attached to the surface after the hard carbon is sintered, thereby improving the quality and performance of the hard carbon negative electrode material.

Description

Technical Field

[0001] The invention belongs to the technical field of roller hearth furnaces, and in particular relates to a roller hearth furnace used for sintering hard carbon negative electrodes of sodium ion batteries. Background Art

[0002] With the rapid development of electric vehicles and energy storage systems, sodium-ion batteries (Na-ion batteries) have attracted widespread attention as a potential alternative to lithium-ion batteries. Sodium-ion batteries have the advantages of abundant raw material resources and low cost, and show strong application potential in large-scale energy storage and electric transportation. Among the negative electrode materials of sodium-ion batteries, hard carbon has become the research focus of sodium-ion battery negative electrode materials because of its excellent electrochemical properties and good cycle stability.

[0003] In the preparation process of hard carbon negative electrode materials, the sintering process is one of the key steps that affects its performance. The sintering process not only determines the structure and morphology of hard carbon materials, but also directly affects their electrochemical properties. However, during the sintering process of hard carbon negative electrode materials, the presence of dust and environmental pollutants has an adverse effect on the sintering effect. Dust particles will adhere to the surface of hard carbon or react with hard carbon, resulting in uneven surface, structural defects or reduced performance, thereby affecting the efficiency and stability of the battery.

[0004] In addition, hard carbon materials often form oxides and carbides on the surface during high-temperature heat treatment. These oxides and carbides interact with the hard carbon matrix, thereby affecting the electrochemical properties of the material. For example, the formation of oxides will lead to a decrease in the surface conductivity of the material, while the formation of carbides will cause the loss of surface active sites, thereby affecting the charge and discharge performance and cycle life of the battery. Therefore, how to effectively control dust pollution before sintering and oxides and carbonized reactants attached to the surface after sintering has become a key issue in improving the quality and performance of hard carbon negative electrode materials. Summary of the invention

[0005] The present invention aims at solving the problems in the prior art and proposes the following technical solutions: A roller hearth furnace for sintering hard carbon negative electrodes of sodium ion batteries, comprising a roller hearth furnace body, the roller hearth furnace body comprising a starting section, a sintering section and a tail section, the starting section and the tail section of the roller hearth furnace body being respectively provided with a purification mechanism and an active impurity removal mechanism; The purification mechanism includes a filter assembly and a circulation assembly. The circulation assembly acts on the air in the initial section of the roller furnace body, and the air is purified by the filter assembly and then transported to the active impurity removal mechanism. The active impurity removal mechanism includes an impurity removal component and a cold filter component. The impurity removal component includes a discharge stage and a dust collecting stage placed at the end section of the roller furnace body. The discharge stage includes a plurality of horizontal and equidistantly arranged electrode plates, and the electrode plate arrangement direction is parallel to the material travel direction. The dust collecting stage is vertically arranged on the top of the discharge stage and its width matches the width of the furnace cavity of the roller furnace body. The cavity of the dust collecting stage is vertically connected and has a honeycomb-shaped horizontal cross section. A second gas collecting hopper is arranged on the top of the dust collecting stage. The purification mechanism and the active impurity removal mechanism are connected through an air pipe, the output end of which extends to the top of the furnace chamber of the roller furnace body. The air purified by the purification mechanism output by the air pipe is evenly blown to the outer surface of the material after being pressurized at the dust collection stage and diverted at the discharge stage.

[0006] As a preferred embodiment of the above technical solution, the roller furnace body includes conveying rollers, an atmosphere pipe and two partitions, and the two partitions are located at both ends of the sintering section.

[0007] As a preferred embodiment of the above technical solution, the filter assembly includes an upper filter box and a lower filter box arranged on the top of the roller furnace body, and multiple filter screens are detachably installed inside the upper filter box and the lower filter box. The filter diameters of the multiple filter screens decrease successively, and the head ends of the filter screens are fixedly connected with handles.

[0008] As a preferred embodiment of the above technical solution, the circulation assembly includes an air intake pipe interconnected at one side of the upper filter box and a third through pipe interconnected at one side of the lower filter box, and the air intake pipe and the third through pipe are close to the filter screen with the largest filter diameter, and the other end of the third through pipe is interconnected with a first gas collecting hopper, and the first gas collecting hopper is fixedly connected to the side wall of the starting section of the roller furnace body; A first air pump and a second air pump are arranged on the top of the roller furnace body. The input end of the first air pump is connected to the upper filter box through the first through pipe, and the input end of the second air pump is connected to the lower filter box through the fourth through pipe, and the first through pipe and the fourth through pipe are arranged opposite to the air inlet pipe and the third through pipe respectively.

[0009] As a preferred embodiment of the above technical solution, an air supply hopper is fixedly connected to the top wall of the furnace chamber of the starting section of the roller hearth furnace body, and the air outlet of the air supply hopper is arranged obliquely downward and points to the starting section of the roller hearth furnace body; The output end of the first air pump is interconnected with a second through pipe, and the bottom end of the second through pipe is connected to the top of the air delivery hopper.

[0010] As a preferred embodiment of the above technical solution, one end of the gas pipe is connected to the output end of the second air pump, and the other end of the gas pipe extends to the top of the furnace chamber of the roller furnace body and is cone-shaped.

[0011] As a preferred embodiment of the above technical solution, the impurity removal component further includes a power supply unit arranged on the top of the roller furnace body, and the power supply unit is electrically connected to the discharge stage and the dust collection stage; The power supply unit includes a high voltage power supply, a transformer and a rectifier.

[0012] As a preferred embodiment of the above technical solution, the impurity removal component also includes a third air pump arranged on the top of the roller furnace body, and the input end of the third air pump is connected to the top of the second air collecting hopper through a fifth through pipe.

[0013] As a preferred embodiment of the above technical solution, the cold filter assembly includes a cold filter box arranged on the top of the roller furnace body, the output end of the third air pump is interconnected with a sixth through pipe, and the tail end of the sixth through pipe penetrates from the top of the cold filter box and extends to the bottom of the cold filter box; The outer side of the cold filter box is interconnected with a liquid inlet pipe, a liquid outlet pipe and an air outlet pipe.

[0014] As a preferred embodiment of the above technical solution, the air outlet pipe and the air inlet pipe are connected to each other through a pipeline.

[0015] The beneficial effects of the present invention are: 1. The purification mechanism of the present invention can not only remove dust and purify the air and hard carbon surface in the starting section of the roller furnace body, reduce the dust and environmental pollutants attached to the hard carbon surface before sintering, but also can perform secondary purification after recycling the air, and transport the clean air to the active impurity removal mechanism, which can clean the hard carbon surface after sintering, eliminate the oxides and carbonization reactants attached to the hard carbon surface after sintering, and improve the quality and performance of the hard carbon negative electrode material; 2. In the present invention, the width of the dust collecting stage matches the width of the furnace chamber of the roller furnace body, reducing the radial ventilation area of ​​the furnace chamber of the roller furnace body, so that the wind blown into the furnace chamber of the roller furnace body by the gas transmission pipe is pressurized and blown into the gaps between the multiple plates, and the multiple plates evenly divide the pressurized wind and blow it to the outer surface of the material, thereby achieving a better cleaning effect on the oxides and carbonized reactants attached to the surface after hard carbon sintering; 3. The hard carbon after sintering carries a lot of heat. Based on the principle of hot air rising, a second air collecting hopper is set on the top of the dust collecting stage, which can prevent the air and the oxides and carbonization reactants in the air from escaping from the side outlet at the end of the roller furnace body to a greater extent; at the same time, the power supply unit, discharge stage and dust collecting stage work, and the air containing oxides and carbonization reactants is ionized by the high-voltage electric field, so that the oxide and carbonization reactant particles are negatively charged and adsorbed to the dust collecting stage for collection; at the same time, the dust collecting stage cavity is vertically connected and the horizontal cross-section is honeycomb-shaped, which can better adsorb oxide and carbonization reactant particles; 4. In the process of removing oxides and carbonized reactants, the air flow also takes away the heat after hard carbon sintering, thus playing an active cooling effect. When it is necessary to clean the oxides and carbonized reactants attached to the dust collecting stage, the power supply unit can be powered off, while the air delivery of the air pipe and the operation of the third air pump are maintained. In this way, the air passing through the dust collecting stage will transport the oxides and carbonized reactants attached to it to the cold filter box, making the operation more convenient; 5. After the air outlet pipe and the air inlet pipe are connected through the pipeline, in cooperation with the air supply pipe, an air circulation is formed between the purification mechanism and the active impurity removal mechanism, which further improves the air purification effect at the starting section of the roller furnace body and the purification effect of surface attachments after hard carbon sintering; at the same time, it also reduces the exchange of air with the outside of the roller furnace body, ensuring the stability of purification of the purification mechanism and the active impurity removal mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The three-dimensional structure schematic diagram of the roller furnace used for sintering the hard carbon negative electrode of the sodium ion battery in the embodiment is shown; Figure 2 It is shown that Figure 1 Enlarged view of point A in the middle; Figure 3 The three-dimensional structure schematic diagram of the purification mechanism in the roller furnace used for sintering the hard carbon negative electrode of the sodium ion battery in the embodiment is shown; Figure 4 The figure shows a cross-sectional view of the internal structure of the roller hearth furnace body in the roller hearth furnace used for sintering the hard carbon negative electrode of the sodium ion battery in the embodiment; Figure 5 The three-dimensional structure schematic diagram of the discharge stage and the dust collection stage in the roller furnace used for sintering the hard carbon negative electrode of the sodium ion battery in the embodiment is shown; Figure 6 Shown is a schematic diagram of the internal structure of a cold filter box in a roller furnace used for sintering hard carbon negative electrodes for sodium ion batteries in an embodiment.

[0017] In the figure: 10, roller furnace body; 11, conveying roller; 12, partition; 13, atmosphere pipe; 20. Purification mechanism; 21. Filter assembly; 22. Circulation assembly; 211. Upper filter box; 212. Lower filter box; 213. Filter screen; 214. Handle; 221. Air inlet pipe; 222. First through pipe; 223. First air pump; 224. Second through pipe; 225. Air delivery hopper; 226. First air collecting hopper; 227. Third through pipe; 228. Fourth through pipe; 229. Second air pump; 30. Gas pipeline; 41. impurity removal component; 42. cold filter component; 411. power supply unit; 412. discharge stage; 413. dust collection stage; 414. second air collecting hopper; 415. fifth through pipe; 416. third air pump; 421. sixth through pipe; 422. cold filter box; 423. liquid inlet pipe; 424. liquid outlet pipe; 425. air outlet pipe. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments.

[0019] Example; such as Figure 1 As shown, a roller hearth furnace for sintering hard carbon negative electrodes of sodium ion batteries comprises a roller hearth furnace body 10, wherein the roller hearth furnace body 10 comprises a starting section, a sintering section and a final section, wherein the starting section and the final section of the roller hearth furnace body 10 are respectively provided with a purification mechanism 20 and an active impurity removal mechanism; the purification mechanism 20 comprises a filtering component 21 and a circulation component 22, wherein the circulation component 22 acts on the air of the starting section of the roller hearth furnace body 10, and the air is purified by the filtering component 21 and then transported to the active impurity removal mechanism; in the present invention, the material (i.e., hard carbon) enters from the starting section of the roller hearth furnace body 10, then passes through the sintering section for calcination, and is transported out from the final section after sintering. The purification mechanism 20 in the present invention can not only remove dust and purify the air and hard carbon surface in the starting section of the roller furnace main body 10, reducing the dust and environmental pollutants attached to the hard carbon surface before sintering, but also can perform secondary purification after recycling the air, and transport the clean air to the active impurity removal mechanism. The active impurity removal mechanism can clean the hard carbon surface after sintering, eliminate oxides and carbonization reactants attached to the surface of the hard carbon after sintering, and improve the quality and performance of the hard carbon negative electrode material.

[0020] like Figure 2 , Figure 3 , Figure 4As shown, the filter assembly 21 includes an upper filter box 211 and a lower filter box 212 arranged on the top of the roller furnace body 10, and multiple filter screens 213 are detachably installed inside the upper filter box 211 and the lower filter box 212. The filter diameters of the multiple filter screens 213 decrease successively, and the head ends of the filter screens 213 are fixedly connected to handles 214; the circulation assembly 22 includes an air intake pipe 221 interconnected on one side of the upper filter box 211 and a third through pipe 227 interconnected on one side of the lower filter box 212, and the air intake pipe 221 and the third through pipe 227 are close to the filter screen 213 with the largest filter diameter, and the other end of the third through pipe 227 is interconnected with a first air collecting hopper 226, and the first air collecting hopper 226 is fixedly connected to the side wall of the starting section of the roller furnace body 10. ; A first air pump 223 and a second air pump 229 are arranged on the top of the roller furnace body 10, the input end of the first air pump 223 is connected with the upper filter box 211 through the first through pipe 222, the input end of the second air pump 229 is connected with the lower filter box 212 through the fourth through pipe 228, and the first through pipe 222 and the fourth through pipe 228 are arranged opposite to the air inlet pipe 221 and the third through pipe 227 respectively; an air supply hopper 225 is fixedly connected to the top wall of the furnace chamber of the starting section of the roller furnace body 10, and the air outlet of the air supply hopper 225 is inclined downward and points to the starting section of the roller furnace body 10; the output end of the first air pump 223 is interconnected with the second through pipe 224, and the bottom end of the second through pipe 224 is connected to the top of the air supply hopper 225.

[0021] The working principle of the purification mechanism 20 is as follows: the first air pump 223 works, and under the connection of the first through pipe 222, the air inside the upper filter box 211 is extracted to generate negative pressure inside the upper filter box 211. Under the action of negative pressure, the air enters the upper filter box 211 from the intake pipe 221, is filtered and purified by multiple filter screens 213, and then is transported to the air delivery hopper 225 through the second through pipe 224. In the present invention, the filter diameters of the multiple filter screens 213 decrease successively, the intake pipe 221 is close to the filter screen 213 with the largest filter diameter, and the intake pipe 221 and the first through pipe 222 are arranged opposite to each other, so that the air entering the inner cavity of the upper filter box 211 from the intake pipe 221 will be purified and dusted step by step by the multiple filter screens 213, and the dust removal effect is good and the air filtering efficiency is high; the filter screen 213 in the present invention is detachable, and the staff replaces or cleans the filter screen 213 through the handle 214 , which is more convenient for daily use; the air outlet of the air supply hopper 225 is tilted downward and points to the starting section of the roller furnace body 10, so that the air delivered to the air supply hopper 225 can be blown to the hard carbon surface of the starting section of the roller furnace body 10, and the dust attached to its surface is blown out of the side opening of the furnace cavity of the roller furnace body 10 together with the surrounding air; at the same time, the second air pump 229 works, and under the connection of the fourth through pipe 228, a negative pressure is generated inside the lower filter box 212, and under the connection of the third through pipe 227, a negative pressure is further generated in the first air collecting hopper 226, so that the air blown out of the side opening of the furnace cavity of the roller furnace body 10 is sucked into the inner cavity of the lower filter box 212 by the first air collecting hopper 226 again. Similarly, under the multi-stage filtration and dust removal of the filter screen 213 in the inner cavity of the lower filter box 212, after secondary purification, it is transported to the active impurity removal mechanism through the air supply pipe 30.

[0022] like Figure 1 , Figure 4 As shown, one end of the gas pipe 30 is connected to the output end of the second air pump 229, and the other end of the gas pipe 30 extends to the top of the furnace chamber of the roller furnace body 10 and is cone-shaped; the cone-shaped design can allow the secondary purified air to be blown more evenly into the furnace chamber of the rear section of the roller furnace body 10, and the cone-shaped air outlet is an oblique setting similar to the air supply hopper 225, so that its blowing direction is facing the hard carbon surface after sintering.

[0023] like Figure 1 , Figure 4 , Figure 5As shown, the active impurity removal mechanism includes an impurity removal component 41 and a cold filter component 42. The impurity removal component 41 includes a discharge stage 412 and a dust collecting stage 413 disposed at the end section of the roller furnace body 10. The discharge stage 412 includes a plurality of horizontal and equidistantly arranged electrode plates, and the electrode plate arrangement direction is parallel to the material travel direction. The dust collecting stage 413 is vertically arranged at the top of the discharge stage 412 and its width matches the width of the furnace cavity of the roller furnace body 10. The cavity of the dust collecting stage 413 is vertically connected and its horizontal cross section is honeycomb-shaped. 13 is provided with a second gas collecting hopper 414 at the top; the impurity removal component 41 also includes a power supply unit 411 arranged on the top of the roller furnace body 10, and the power supply unit 411 is electrically connected to the discharge stage 412 and the dust collecting stage 413; the power supply unit 411 includes a high-voltage power supply, a transformer and a rectifier; the impurity removal component 41 also includes a third air pump 416 arranged on the top of the roller furnace body 10, and the input end of the third air pump 416 is connected to the top of the second gas collecting hopper 414 through a fifth through pipe 415.

[0024] In the present invention, the dust collecting stage 413 is placed in the furnace cavity of the roller furnace body 10 and its width matches the width of the furnace cavity of the roller furnace body 10, thereby reducing the radial ventilation area of ​​the furnace cavity of the roller furnace body 10, so that the wind blown into the furnace cavity of the roller furnace body 10 by the gas delivery pipe 30 is pressurized and blown into the gaps between the multiple plates, and the multiple horizontal and equidistantly arranged plates evenly divide the pressurized wind, so that it is evenly blown to the outer surface of the material, so that the oxides and carbonized reactants attached to the surface after hard carbon sintering have a better cleaning effect; At the same time, the hard carbon after sintering carries a large amount of heat. Based on the principle of hot air rising, a second air collecting hopper 414 is set on the top of the dust collecting stage 413, and is connected to the third air pump 416 through the fifth through pipe 415. In this way, the operation of the third air pump 416 makes the second air collecting hopper 414 generate negative pressure, and absorbs air and oxides and carbonization reactants in the air upward. In addition, the second air collecting hopper 414, the discharge stage 412, and the dust collecting stage 413 have a certain length in the axial direction of the roller furnace body 10, which can avoid the air and the oxides and carbonization reactants in the air from the end of the roller furnace body 10 to a greater extent. At the same time, the power supply unit 411, the discharge stage 412 and the dust collecting stage 413 work, and the air containing oxides and carbonization reactants is ionized by the high-voltage electric field. The oxides and carbonization reactants in the airflow are charged and separated from the airflow under the action of the electric field; in the strong electric field, they are ionized into positive ions and electrons, and the electrons encounter the oxide and carbonization reactant particles in the process of rushing to the dust collecting stage 413, so that the oxide and carbonization reactant particles are negatively charged and adsorbed to the dust collecting stage 413 and collected; the design of the dust collecting stage 413 cavity being vertically connected and the horizontal cross-section being honeycomb-shaped can better adsorb the oxide and carbonization reactant particles. It should be noted here that: when the hard carbon material is heat treated, especially at high temperatures, some oxides and carbides will often form on the surface. Specifically, common ones include iron oxides such as Fe3O4 or other iron-based compounds. These substances will adhere to the surface of the hard carbon. At the same time, these substances have certain particle sizes and charge characteristics. Because of their large inertia, they are easily affected by the electric field force and are more easily adsorbed by static electricity. Therefore, the dust collecting stage 413 has a better effect of adsorbing and removing oxides and carbonized reactants. In the process of removing oxides and carbonized reactants, the air flow also takes away the heat after the hard carbon is sintered, thereby playing an active cooling effect. When it is necessary to clean the oxides and carbonized reactants attached to the dust collecting stage 413, the power supply unit 411 can be powered off, while maintaining the air delivery of the air pipe 30 and the operation of the third air pump 416, so that the air passing through the dust collecting stage 413 will transport the oxides and carbonized reactants attached thereto to the cold filter box 422.

[0025] like Figure 6 As shown, the cold filter assembly 42 includes a cold filter box 422 arranged on the top of the roller furnace body 10, the output end of the third air pump 416 is interconnected with the sixth through pipe 421, the tail end of the sixth through pipe 421 penetrates from the top of the cold filter box 422 and extends to the bottom of the cold filter box 422; the outer side of the cold filter box 422 is interconnected with a liquid inlet pipe 423, a liquid outlet pipe 424 and an air outlet pipe 425.

[0026] As can be seen from the above, when the active impurity removal mechanism is working, the air flow also takes away the heat after the hard carbon is sintered, forming hot air that is transported to the bottom of the cold filter box 422 through the sixth through pipe 421. A heat dissipation liquid is arranged inside the cold filter box 422. This embodiment uses water, so that the hot air can be cooled and then discharged from the outlet pipe 425; at the same time, when the flowing air cleans the oxide and carbonization reactant particles attached to the dust collecting stage 413, the oxide and carbonization reactant particles doped in the air will be filtered by the water, and the clean air will be discharged from the outlet pipe 425; by setting the liquid inlet pipe 423 and the liquid outlet pipe 424, the water inside the cold filter box 422 can form a water circulation, thereby ensuring the cooling effect on the hot air and the filtering effect on the oxide and carbonization reactant particles.

[0027] like Figure 4 As shown, the roller furnace body 10 includes a conveying roller 11, an atmosphere pipe 13 and two partitions 12, and the two partitions 12 are located at both ends of the sintering section.

[0028] By setting the partition 12, the sintering section of the roller furnace body 10 can be insulated to reduce heat loss. At the same time, the atmosphere of the sintering section can be better controlled and the mixing of external air into the sintering section can be reduced to ensure the sintering quality.

[0029] like Figure 1 As shown, the air outlet pipe 425 and the air inlet pipe 221 are connected via a pipeline.

[0030] When the air outlet pipe 425 and the air inlet pipe 221 are connected through the pipeline, in cooperation with the air supply pipe 30, an air circulation is formed between the purification mechanism 20 and the active impurity removal mechanism. Under this air circulation, the multi-level filtration and purification through the filter component 21 and the cold filter component 42 further improves the air purification effect of the starting section of the roller furnace body 10 and the purification effect of the surface attachments after hard carbon sintering. At the same time, it also reduces the exchange of air with the outside of the roller furnace body 10, ensuring the stability of the purification of the purification mechanism 20 and the active impurity removal mechanism.

[0031] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them.

Claims

1. A roller hearth furnace for sintering hard carbon negative electrodes for sodium ion batteries, comprising a roller hearth furnace body (10), the roller hearth furnace body (10) comprising a starting section, a sintering section and a final section, characterized in that: The starting section and the ending section of the roller furnace body (10) are respectively provided with a purification mechanism (20) and an active impurity removal mechanism; The purification mechanism (20) comprises a filter assembly (21) and a circulation assembly (22), wherein the circulation assembly (22) acts on the air at the start of the roller furnace body (10), and is purified by the filter assembly (21) and then transported to the active impurity removal mechanism; The active impurity removal mechanism comprises an impurity removal component (41) and a cold filter component (42); the impurity removal component (41) comprises a discharge stage (412) and a dust collecting stage (413) disposed at the rear section of the roller furnace body (10); the discharge stage (412) comprises a plurality of horizontally and equidistantly arranged electrode plates, and the arrangement direction of the electrode plates is parallel to the material travel direction; the dust collecting stage (413) is vertically arranged at the top of the discharge stage (412) and has a width matching the width of the furnace cavity of the roller furnace body (10); the cavity of the dust collecting stage (413) is vertically connected and has a honeycomb-shaped horizontal cross section; a second gas collecting hopper (414) is disposed at the top of the dust collecting stage (413); The purification mechanism (20) and the active impurity removal mechanism are connected via an air delivery pipe (30), the output end of the air delivery pipe (30) extending to the top of the furnace chamber of the roller furnace body (10), and the air purified by the purification mechanism (20) output from the air delivery pipe (30) is evenly blown to the outer surface of the material after being pressurized by the dust collection stage (413) and diverted by the discharge stage (412).

2. The roller hearth furnace for sintering hard carbon negative electrodes for sodium ion batteries according to claim 1, characterized in that: The roller furnace body (10) comprises a conveying roller (11), an atmosphere pipe (13) and two partitions (12), wherein the two partitions (12) are located at two ends of the sintering section.

3. The roller hearth furnace for sintering hard carbon negative electrode of sodium ion battery according to claim 1, characterized in that: The filter assembly (21) comprises an upper filter box (211) and a lower filter box (212) arranged on the top of the roller furnace body (10); a plurality of filter screens (213) are detachably installed inside the upper filter box (211) and the lower filter box (212); the filter diameters of the plurality of filter screens (213) decrease in sequence; and a handle (214) is fixedly connected to the head end of each of the filter screens (213).

4. The roller hearth furnace for sintering hard carbon negative electrodes for sodium ion batteries according to claim 3, characterized in that: The circulation component (22) comprises an air intake pipe (221) interconnected with one side of the upper filter box (211) and a third through pipe (227) interconnected with one side of the lower filter box (212), and the air intake pipe (221) and the third through pipe (227) are close to the filter screen (213) with the largest filter diameter, and the other end of the third through pipe (227) is interconnected with a first gas collecting hopper (226), and the first gas collecting hopper (226) is fixedly connected to the starting section side wall of the roller furnace body (10); A first air pump (223) and a second air pump (229) are arranged on the top of the roller furnace body (10); an input end of the first air pump (223) is connected to the upper filter box (211) via a first through pipe (222); an input end of the second air pump (229) is connected to the lower filter box (212) via a fourth through pipe (228); and the first through pipe (222) and the fourth through pipe (228) are arranged opposite to the air inlet pipe (221) and the third through pipe (227), respectively.

5. The roller hearth furnace for sintering hard carbon negative electrode of sodium ion battery according to claim 4, characterized in that: An air supply hopper (225) is fixedly connected to the top wall of the furnace chamber at the starting section of the roller furnace body (10); an air outlet of the air supply hopper (225) is arranged obliquely downward and points to the starting section of the roller furnace body (10); The output end of the first air pump (223) is interconnected with a second through pipe (224), and the bottom end of the second through pipe (224) is connected to the top of the air delivery hopper (225).

6. The roller hearth furnace for sintering hard carbon negative electrodes for sodium ion batteries according to claim 4, characterized in that: One end of the gas delivery pipe (30) is connected to the output end of the second air pump (229), and the other end of the gas delivery pipe (30) extends to the top of the furnace chamber of the roller furnace body (10) and is in a cone shape.

7. The roller hearth furnace for sintering hard carbon negative electrodes for sodium ion batteries according to claim 1, characterized in that: The impurity removal component (41) further comprises a power supply unit (411) arranged on the top of the roller furnace body (10), and the power supply unit (411) is electrically connected to the discharge stage (412) and the dust collection stage (413); The power supply unit (411) comprises a high-voltage power supply, a transformer and a rectifier.

8. The roller hearth furnace for sintering hard carbon negative electrodes for sodium ion batteries according to claim 4, characterized in that: The impurity removal component (41) further comprises a third air pump (416) arranged on the top of the roller furnace body (10), and an input end of the third air pump (416) and a top of the second air collecting hopper (414) are connected via a fifth through pipe (415).

9. The roller hearth furnace for sintering hard carbon negative electrodes for sodium ion batteries according to claim 8, characterized in that: The cold filter assembly (42) comprises a cold filter box (422) arranged on the top of the roller furnace body (10); the output end of the third air pump (416) is interconnected with a sixth through pipe (421); the tail end of the sixth through pipe (421) penetrates from the top of the cold filter box (422) and extends to the bottom of the cold filter box (422); The outer side of the cold filter box (422) is interconnected with a liquid inlet pipe (423), a liquid outlet pipe (424), and an air outlet pipe (425).

10. The roller hearth furnace for sintering hard carbon negative electrodes for sodium ion batteries according to claim 9, characterized in that: The air outlet pipe (425) and the air inlet pipe (221) are connected via a pipeline.

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