CN107651678B

CN107651678B - Powder heat treatment furnace

Info

Publication number: CN107651678B
Application number: CN201610591839.6A
Authority: CN
Inventors: 贺俊德; 罗旺; 朱登伟
Original assignee: Zhuzhou Chenxin Induction Equipment Co ltd
Current assignee: Zhuzhou Chenxin Induction Equipment Co ltd
Priority date: 2016-07-26
Filing date: 2016-07-26
Publication date: 2023-08-11
Anticipated expiration: 2036-07-26
Also published as: CN107651678A

Abstract

The application discloses a powder heat treatment furnace. The powder heat treatment furnace comprises a furnace shell with a closed hearth, a crucible arranged in the closed hearth and a heat preservation cover arranged at the top end of the furnace shell; the heat preservation cover is provided with a feed inlet, and the bottom end of the furnace shell is provided with a discharge outlet; an induction coil is arranged between the outer wall of the crucible and the inner wall of the furnace shell; the upper part in the crucible is provided with a rotating disc and a rotating shaft which penetrates through the heat preservation cover and is fixedly connected with the rotating disc. The application realizes the continuous production of powder materials, and has good energy-saving effect and high heating efficiency.

Description

Powder heat treatment furnace

Technical Field

The application relates to a powder heat treatment furnace, and belongs to the field of material graphitization equipment.

Background

With the development of new energy power, lithium ion batteries are increasingly favored by investors, and the market of carbon anode materials serving as a key component of the lithium ion batteries is also faced with blowout development. One key step in the production process of the carbon cathode material is graphitization purification. Graphitization refers to a hexagonal plane network structure, i.e. a graphite crystallite structure, in which carbon atoms are changed from random irregular arrangement to regular arrangement at high temperature, and the purpose of the graphitization is to obtain performances of high electric conductivity, high heat conduction, corrosion resistance, friction resistance and the like of graphite. The graphitization temperature can reach 3100 ℃, the higher the temperature is, the more perfect the structure development of graphite microcrystals is, and the graphitization degree is improved; at the same time, other atoms with low melting point are discharged in a gas form at the high temperature, so that the purification of the material is realized. The equipment used for improving the graphitization degree or purity is called a graphitization furnace, and materials requiring graphitization treatment also include carbon nanotubes, nuclear graphite, natural graphite, artificial graphite and the like.

The Acheson furnace is a furnace for realizing large-scale high-temperature graphitization production, and is characterized by large scale, but because the Acheson furnace is of an open structure, tail gas is not subjected to centralized treatment, and a large amount of filler coke is used for heating by resistance, so that high energy consumption, environment pollution and uneven temperature are caused. Although the graphitizing furnace with the internal serial electrode is improved by the technology, the problems of high energy consumption, large pollution and uneven temperature are not solved. Patent CN201010108189.8 discloses a vertical high-temperature continuous graphitizing furnace, which is characterized in that an upper electrode pair and a lower electrode pair are connected with a direct current power supply, materials are used as resistors to generate heat, and the defects are high energy consumption and low heating efficiency. After that, an intermediate frequency induction graphitizing furnace appears, such as a vertical continuous induction high-temperature graphitizing furnace is disclosed in chinese patent application number CN201410666556.4, an ultra-high temperature graphitizing treatment device is disclosed in chinese patent application number CN201410016297.0, a continuous high-temperature graphite purifying device is disclosed in chinese patent application number CN201210487294.6, a graphite purifying and graphitizing high-temperature vertical continuous induction heating furnace is disclosed in chinese patent application number CN200910042891.6, and a continuous vertical intermediate frequency high-temperature high-purity graphite production device is disclosed in chinese patent application number CN 200920009018.2.

The traditional Acheson furnace has the disadvantages of high energy consumption, high pollution and uneven heating temperature; the existing vertical continuous graphitizing furnace is provided with an electrode direct current heating furnace and an induction heating furnace, and most of the vertical continuous graphitizing furnace adopts the flow of materials from top to bottom to realize continuous production, but the heat conducting property of powder materials is poor, so that the temperature inside a hearth is uneven, and the product performance is good and uneven.

Disclosure of Invention

In order to solve the problem of poor product performance caused by uneven temperature, the application aims to provide a powder heat treatment furnace, which can realize continuous production of powder materials, and has the advantages of good energy-saving effect and high heating efficiency.

In order to achieve the above purpose, the technical scheme adopted by the application is as follows:

a powder heat treatment furnace comprises a furnace shell with a closed hearth, a crucible arranged in the closed hearth and a heat preservation cover arranged at the top end of the furnace shell; the heat preservation cover is provided with a feed inlet, and the bottom end of the furnace shell is provided with a discharge outlet; the structure is characterized in that an induction coil is arranged between the outer wall of the crucible and the inner wall of the furnace shell; the upper part in the crucible is provided with a rotating disc and a rotating shaft which penetrates through the heat preservation cover and is fixedly connected with the rotating disc; preferably, the lower end surface of the rotating disc is provided with a stirring protrusion; preferably, the crucible is a graphite crucible.

From this, heat the powder through induction coil, heating efficiency is high, and energy-conservation, and the rolling disc is to realizing the stirring function to can make the powder heated more even, thereby improved product quality.

According to the embodiment of the application, the application can be further optimized, and the following technical scheme is formed after the optimization:

in order to facilitate the overflow of impurity gas, the rotating disc and the rotating shaft are internally provided with exhaust channels which are mutually communicated. Meanwhile, the exhaust channel is also used as a temperature measuring channel, and a temperature measuring hole is prevented from being independently formed, so that the heat preservation effect of the high-temperature furnace is improved.

Preferably, the lower end of the rotating disc is provided with a plurality of electrodes positioned at the upper part in the crucible; according to the application, the material is heated by the induction heating principle, the upper electrode can be also heated by induction as a heat source, and the powder material can be fully stirred when the electrode rotates, so that the temperature uniformity and the heating efficiency are improved. Preferably, the rotating shaft, the rotating disc and the electrode are internally provided with exhaust channels which are sequentially communicated, so that impurity gas can be conveniently and timely exhausted.

As a specific structural form, the electrode is of a cylindrical structure; preferably, the lower end of the electrode is provided with an inclined through hole, and the inclined through hole is communicated with an exhaust channel of the electrode, so that impurity gas can be conveniently discharged through the exhaust channel.

Surprisingly, the high temperature furnace also heats the electrodes during operation. In order to realize the aim of heating the electrodes simultaneously, the dual effects of electrode heating and induction coil heating are realized, the heating efficiency of the high-temperature furnace is further improved, and the distance between the electrodes and the induction coil is 30mm-300mm; preferably the distance between the electrode and the induction coil is 50mm-200mm.

Preferably, the rotating shaft, the rotating disc and the electrode are all made of graphite materials.

In order to improve the service life of the crucible, a heat preservation layer is arranged between the outer wall of the crucible and the induction coil.

In order to improve the uniformity of heating temperature and simultaneously facilitate stirring of powder, thereby discharging impurity gas, the extending end of the rotating shaft is connected with a driving device; the rotation speed of the rotation shaft is preferably not higher than 6r/min, more preferably 0 to 3r/min.

Preferably, the hearth is cylindrical; preferably, the feeding port and the discharging port are arranged on the axis of the hearth.

Preferably, the powder is at least one of natural crystalline flake graphite powder, soil graphite, artificial graphite powder, carbon negative electrode material, tar carbon, pitch carbon, resin carbon and coal-based carbon. The proportions of the components are not required, and the components may be mixed in any proportion.

Compared with the prior art, the application has the beneficial effects that:

1. the induction heating mode is adopted for heating, so that the efficiency is high, and the energy is saved. The top of the hearth is provided with an electrode, and the hearth can be heated in the same way when in operation and used as a multipoint heat source, so that the temperature uniformity of the hearth is improved. The electrodes can be heated by induction, and serve as a heat source to heat the powder material, so that the material passes through a high-temperature zone for a longer time, and the powder material is heated more fully.

2. The multi-electrode can rotate, and the overflow of impurity gas is more favorable when the temperature uniformity is improved by stirring the material, so that the material is heated more uniformly, the impurity gas is discharged more easily, the speed of feeding and discharging can be adjusted on the other hand, and the occurrence of congestion caused by unsmooth material flow in the furnace is prevented. .

3. The electrode part is skillfully utilized to design the exhaust channel, so that the exhaust channel can be used as an exhaust channel when impurity gas overflows, an additional exhaust pipeline is not required, and heat loss is reduced.

4. The whole crucible is arranged in the stainless steel closed hearth, so that heat loss can be reduced, and external air can be isolated.

5. The intermediate frequency heating is used, no low-voltage large current is needed, low-voltage rectification is not needed, the copper loss and iron loss consumption of the transformer are reduced, and the electric heating efficiency is improved by 50%.

Drawings

Fig. 1 is a schematic diagram of the structure of an embodiment of the present application.

Detailed Description

The application will be described in detail below with reference to the drawings in connection with embodiments. It should be noted that, without conflict, the embodiments of the present application and features of the embodiments may be combined with each other. For convenience of description, the words "upper", "lower", "left" and "right" are used hereinafter to denote only the directions corresponding to the upper, lower, left, and right directions of the drawings, and do not limit the structure.

As shown in FIG. 1, the powder heat treatment furnace comprises a furnace shell 11, a graphite crucible 4 positioned in a furnace chamber, a rotating disc 2 arranged on the upper part of the graphite crucible 4, an electrode 3 connected with the rotating disc 2, and a rotating shaft 1, wherein the rotating shaft 1, the rotating disc 2 and the electrode 3 are provided with channels communicated with each other, the channels can be used as exhaust channels of impurity gas, the rotating shaft 1 penetrates through a heat-insulating cover 10 and is insulated with the heat-insulating cover through a ceramic sleeve, one end positioned outside the furnace chamber can be connected with a rotating device, and the powder heat treatment furnace further comprises a heat-insulating layer 5 and an induction coil 6 positioned on the outer side of the crucible 4, a feeding bin 9 positioned at the position of a feed inlet, a cooling zone 7 positioned at the bottom of a discharge hole and a receiving bin 8. The material slowly gets into crucible 4 by feeding storehouse 9, and electrode 3 rotatory stirring material under external power makes the temperature in the material more even on the one hand, is favorable to the impurity gas in the material to spill over to discharge through the passageway on electrode 3, on the other hand electrode 3 is simultaneously by induction heating, because fixed coefficient of heat conductivity is greater than the coefficient of heat conductivity of powder far away, and a plurality of electrodes are as the heat source to heat the powder material.

The rotating shaft, the rotating disc and the electrode are all made of graphite. The rotating disc and the rotating shaft are provided with a pore canal communicated after being connected.

The electrodes are of cylindrical structures, the number of the electrodes is not less than 2, and the lower ends of the electrodes are provided with inclined through holes which are uniformly distributed. The distance between the electrode and the induction coil is set to be 30-300mm, and the preferential distance is 50-200mm. The electrode rotation speed is not higher than 6r/min, preferably 0-3r/min.

The feed inlet and the discharge outlet are positioned on the shaft center of the hearth.

The powder is at least one of natural crystalline flake graphite powder, soil graphite, artificial graphite powder, carbon cathode material, tar carbon, asphalt carbon, resin carbon and coal-based carbon.

The foregoing examples are set forth in order to provide a more thorough description of the present application and are not intended to limit the scope of the application, and various modifications of the application, which are equivalent to those skilled in the art upon reading the present application, will fall within the scope of the application as defined in the appended claims.

Claims

1. A powder heat treatment furnace comprises a furnace shell (11) with a closed hearth, a crucible (4) arranged in the closed hearth and a heat preservation cover (10) arranged at the top end of the furnace shell (11); the heat preservation cover (10) is provided with a feed inlet, and the bottom end of the furnace shell (11) is provided with a discharge outlet; an induction coil (6) is arranged between the outer wall of the crucible (4) and the inner wall of the furnace shell (11); the crucible is characterized in that a rotating disc (2) and a rotating shaft (1) which penetrates through a heat preservation cover (10) and is fixedly connected with the rotating disc (2) are arranged at the upper part in the crucible (4);

the lower end of the rotating disc (2) is provided with a plurality of electrodes (3) positioned at the upper part in the crucible (4); the electrode (3) is heated by induction and is used as a heat source, and the powder material can be fully stirred when the electrode (3) rotates;

an exhaust channel which is communicated in sequence is arranged in the rotating shaft (1), the rotating disc (2) and the electrode (3);

the rotating shaft (1), the rotating disc (2) and the electrode (3) are all made of graphite materials.

2. The powder heat treatment furnace according to claim 1, characterized in that the crucible (4) is a graphite crucible.

3. The powder heat treatment furnace according to claim 1, wherein the electrode (3) has a cylindrical structure.

4. A powder heat treatment furnace according to claim 3, characterized in that the lower end of the electrode (3) is provided with an inclined through hole.

5. The powder heat treatment furnace according to claim 1, characterized in that the distance between the electrode (3) and the induction coil (6) is 30-300 mm.

6. The powder heat treatment furnace according to claim 5, characterized in that the distance between the electrode (3) and the induction coil (6) is 50-200mm.

7. The powder heat treatment furnace according to claim 1, characterized in that a heat insulating layer (5) is provided between the outer wall of the crucible (4) and the induction coil (6).

8. A powder heat treatment furnace according to claim 1, characterized in that the protruding end of the rotating shaft (1) is coupled to a drive means.

9. The powder heat treatment furnace according to claim 8, wherein the rotational speed of the rotational shaft (1) is not higher than 6r/min.

10. The powder heat treatment furnace according to claim 9, characterized in that the rotational speed of the rotational shaft (1) is 0-3r/min.

11. The powder heat treatment furnace according to claim 1, wherein the hearth is cylindrical.

12. The powder heat treatment furnace according to claim 11, wherein the feed port and the discharge port are both disposed on an axial line of the furnace chamber.

13. The powder heat treatment furnace according to claim 1, wherein the powder is at least one of natural crystalline flake graphite powder, soil graphite, artificial graphite powder, carbon negative electrode material, tar carbon, pitch carbon, resin carbon, and coal-based carbon.

14. The powder heat treatment furnace according to claim 1, wherein a stirring projection is provided on a lower end surface of the rotary plate.