Pyrolysis device for recovering graphite from black powder leaching residues

Abstract

The pyrolysis device comprises a pyrolysis furnace, a driving mechanism and a conveying mechanism, a graphite boat is arranged in the pyrolysis furnace and used for containing graphite, an inert gas inlet, a raw material distribution opening and a pyrolysis gas outlet are formed in the top of the pyrolysis furnace, the raw material distribution opening is communicated with a raw material buffer bin, and the pyrolysis gas outlet is communicated with a pyrolysis gas outlet. A graphite boat is arranged in the pyrolyzing furnace, a graphite discharging port is formed in the bottom of the pyrolyzing furnace, the driving mechanism penetrates through the pyrolyzing furnace and is in transmission connection with the graphite boat so as to drive the graphite boat to rotate relative to the pyrolyzing furnace, the conveying mechanism comprises a conveying steel belt located below the graphite boat, and the top surface of the conveying steel belt can move towards the graphite discharging port. The pyrolysis device for recovering the graphite from the black powder leaching residues has the advantage of being high in graphite recovery quality.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of graphite recovery, and particularly relates to a pyrolysis device for recovering graphite from black powder leaching residue which is friendly to the environment. BACKGROUND

[0002] The main component of the black powder leaching residue is graphite, and the black powder leaching residue also contains Li, Co, Ni, Mn, Al, Cu, Fe, F, PVDF, electrolyte residues and other impurities. Because graphite is relatively cheap and widely available, it has been given little attention in the past, and there is a lack of motivation for graphite recovery. In the lithium battery recycling industry, it is mainly stored or incinerated in the form of garbage, which is extremely harmful to the environment and causes waste of resources. A small amount of graphite is recovered by flotation and acid leaching, but a large amount of acid waste liquid is generated, which has a large environmental burden and requires end-of-pipe treatment of acid waste liquid, resulting in high treatment cost and environmental pollution. The conventional pyrometallurgical recovery temperature is difficult to reach the boiling point of some metals, and the removal rate of metal impurities such as cobalt, nickel, manganese and copper contained in graphite is low. These impurities still remain in the calcined graphite, which seriously affects its electrochemical performance. Long high-temperature time has the risk of damaging the structure of graphite, and the quality of the recovered graphite is low. SUMMARY

[0003] The present application is made based on the inventors' discovery and understanding of the following facts and problems: The removal effect of impurities in graphite recovery is poor, and the quality is low.

[0004] The present application aims to at least partially solve one of the problems in the related art.

[0005] To this end, an embodiment of the present application provides a pyrolysis device for recovering graphite from black powder leaching residue, comprising a pyrolysis furnace, a driving mechanism and a conveying mechanism. The inside of the pyrolysis furnace is provided with a graphite boat for containing graphite. The top of the pyrolysis furnace is provided with an inert gas inlet, a raw material feeding port and a pyrolysis gas outlet. The raw material feeding port is in communication with the raw material buffer bin. The bottom of the pyrolysis furnace is provided with a graphite discharge port. The driving mechanism passes through the pyrolysis furnace and is in transmission connection with the graphite boat to drive the graphite boat to rotate relative to the pyrolysis furnace. The conveying mechanism comprises a conveying steel belt located below the graphite boat. The top surface of the conveying steel belt is movable towards the graphite discharge port.

[0006] The pyrolysis device for recovering graphite from black powder leaching residue according to the embodiment of the present application has the advantages and technical effects of high quality of recovered graphite.

[0007] In some embodiments, the driving mechanism comprises a rotating motor and a rotating shaft, the rotating motor is arranged on the outer wall of the pyrolysis furnace, one end of the rotating shaft is connected with the output end of the rotating motor, and the other end of the rotating shaft is rotatably connected with the inner wall of the pyrolysis furnace through the pyrolysis furnace and the graphite boat.

[0008] In some embodiments, the graphite boat has a boat cover, the boat cover is pivotally connected with the graphite boat, and a lock catch is arranged on the boat cover to close the graphite boat.

[0009] In some embodiments, a sieve plate is arranged in the graphite boat, the sieve plate divides the internal cavity of the graphite boat into at least two cavities in the thickness direction. Through the sieve hole, the material is dropped between the layers to achieve multiple stirring and dispersion, and local accumulation is avoided. In some embodiments, the driving mechanism further comprises an outer magnetic rotor and an inner magnetic rotor, the output end of the rotating motor is connected with the outer magnetic rotor, one end of the rotating shaft is connected with the inner magnetic rotor, and the outer magnetic rotor is magnetically attracted to the inner magnetic rotor through the furnace wall of the pyrolysis furnace. Non-contact transmission is achieved, and the problem of shaft sealing leakage is completely solved.

[0010] In some embodiments, a return port is arranged at the bottom of the pyrolysis furnace, and the top surface of at least one of the conveying steel belts can move towards the return port.

[0011] In some embodiments, at least two conveying steel belts are arranged in the pyrolysis furnace, the conveying steel belts are spaced apart from adjacent conveying steel belts in the vertical direction, and the moving direction of the top surface of the conveying steel belt is opposite to the conveying direction of the adjacent conveying steel belt.

[0012] In some embodiments, the surface of the conveying steel belt is provided with anti-skid convex patterns and uniformly provided with a plurality of air permeable holes.

[0013] In some embodiments, a pressure adjusting mechanism is further included, the pressure adjusting mechanism comprises a pressure sensor, an electric adjusting valve and an explosion-proof pressure relief valve, the explosion-proof pressure relief valve is arranged on the furnace body of the pyrolysis furnace, and the pressure sensor is electrically connected with the electric adjusting valve on the pyrolysis gas outlet.

[0014] In some embodiments, a water-cooled jacket is further included, the water-cooled jacket is arranged around the outside of the pyrolysis furnace.

[0015] The present application can adopt the Joule heat flash evaporation technology, and the capacitor group in the flash evaporation Joule heating circuit provides electric heating energy to the graphite boat reactant, so that the material is heated to 2500-3000 DEG C in a very short time, the metal in the graphite is flash evaporated and separated from the material. The graphite stays in high temperature for a short time, the energy consumption and the amount of inert gas used are reduced, the structure of the graphite material is not damaged, and the regenerated graphite material has excellent rate performance and cycle stability.

[0016] The high-temperature flue gas generated in the graphite recovery process has a large amount of heat, which can be used to pre-dry the moisture in the waste graphite raw material through flue gas circulation, thereby reducing the energy consumption of the entire system. The feed of the pyrolysis device is sealed from air to avoid the entry of oxygen into the furnace and reduce the consumption of inert gas, thereby avoiding the oxidation of graphite. Through the recycling of heat, the economic benefits of the waste graphite recovery system have a large industrial application and market prospect. BRIEF DESCRIPTION OF DRAWINGS Figure 1 Fig. 1 is a structural schematic diagram of a pyrolysis device for recovering graphite from smut leaching residue according to an embodiment of the present application.

[0017] The reference signs are as follows: 1, pyrolysis furnace; 101, inert gas inlet; 102, raw material feeding port; 103, pyrolysis gas outlet; 104, graphite outlet; 105, return port; 2, graphite boat; 31, rotating motor; 32, rotating shaft; 4, conveying steel belt; 5, water-cooled jacket; 6, coil; 7, raw material buffer bin. DETAILED DESCRIPTION

[0018] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0019] The embodiment of the present application provides a pyrolysis device for recovering graphite from black powder leaching residue, which comprises a pyrolysis furnace 1, a driving mechanism and a conveying mechanism, graphite boats 2 are arranged in the pyrolysis furnace 1 and used for containing graphite, an inert gas inlet 101, a raw material feeding port 102 and a pyrolysis gas outlet 103 are arranged at the top of the pyrolysis furnace 1, the raw material feeding port 102 is communicated with a raw material buffer bin, a graphite discharging port 104 is arranged at the bottom of the pyrolysis furnace 1, the driving mechanism is in transmission connection with the graphite boats 2 and used for driving the graphite boats 2 to rotate relative to the pyrolysis furnace 1, and the conveying mechanism comprises a conveying steel belt arranged below the graphite boats 2, and the top surface of the conveying steel belt can move to the graphite discharging port 104. The pyrolysis furnace 1 provides a sealed and temperature-controlled pyrolysis environment, the graphite boats 2 are used for containing graphite which needs to be recovered by pyrolysis, the driving mechanism drives the graphite boats 2 to rotate, so that the graphite which has completed pyrolysis can be poured on the conveying mechanism, and the conveying mechanism continuously discharges the graphite after pyrolysis, thereby forming a streamlined operation of dynamic pyrolysis and continuous discharging. The graphite boats 2 reduce the dead angle of the raw material in the furnace, the driving mechanism reduces the residual material which is not completely pyrolyzed, and the conveying mechanism improves the recovery rate of the graphite. The graphite boats 2 provide independent and concentrated pyrolysis space for the black powder leaching residue, avoid local overheating or adhesion caused by the direct contact of the raw material with the furnace wall, and can realize uniform heating of the graphite under the driving of the driving mechanism. The inert gas inlet 101 is used for introducing nitrogen, argon or other inert gases into the pyrolysis furnace 1, so as to build an oxygen-free pyrolysis atmosphere and prevent the graphite from being oxidized. The flow of the inert gas can carry away organic impurity gas generated in the pyrolysis process, accelerate the removal of impurities, improve the purification effect of the graphite, the inert gas atmosphere can balance the pressure in the furnace, and air backflow caused by local negative pressure is avoided. The raw material feeding port 102 buffers the raw material to avoid direct impact of the raw material on the graphite boats 2 or supply material interruption. The pyrolysis gas outlet 103 discharges organic impurity gas generated in the pyrolysis process, reduces the impurity concentration in the furnace, promotes the continuous decomposition of organic impurities in the black powder leaching residue, and avoids the accumulation of pyrolysis gas to cause the pressure in the furnace to rise. The graphite discharging port 104 is arranged at the bottom of the furnace and uses gravity to assist the graphite to fall to the conveying steel belt, so as to reduce the material loss in the conveying process, the discharging position is accurately connected with the conveying steel belt, the graphite is prevented from scattering into the dead angle of the furnace during the discharging process, and the material recovery rate is improved. The pyrolysis furnace 1 uses the Joule heat flash evaporation technology, provides electric heating energy to the reactants through the capacitor group in the flash evaporation Joule heating loop, raises the material to 2500-3000 DEG C in a very short time, and separates the metal in the graphite from the material by flash evaporation. The graphite stays in high temperature for a short time, the energy consumption and the amount of inert gas used are reduced, the structure of the graphite material is not damaged, the regenerated graphite material has excellent rate performance and cycle stability.

[0020] In some embodiments, the driving mechanism comprises a rotating motor 31 and a rotating shaft 32, the rotating motor 31 is arranged on the outer wall of the pyrolysis furnace 1, one end of the rotating shaft is connected with the output end of the rotating motor 31, and the other end of the rotating shaft penetrates through the pyrolysis furnace 1 and the graphite boats 2 and is in rotary connection with the inner wall of the pyrolysis furnace 1.

[0021] Specifically, the rotating motor 31 is externally arranged, which can avoid direct contact with high temperature and corrosive environment, and is far away from dust pollution. One end of the rotating shaft 32 is rigidly connected with the output end of the motor, and the other end penetrates through the pyrolysis furnace 1 and penetrates through the graphite boat 2 to form a rotating support with the inner wall of the pyrolysis furnace 1. The rotating shaft 32 forms a fixed linkage with the graphite boat 2, which ensures that the torque of the motor can be efficiently transmitted to the graphite boat 2 to drive it to rotate stably. The rotating shaft is supported by two points to improve the transmission stability, and the graphite boat 2 does not shake or deviate when rotating. After the motor is externally arranged, the motor can be maintained without disassembling the pyrolysis furnace 1, thereby reducing downtime.

[0022] In some embodiments, the graphite boat 2 has a boat cover at the top, the boat cover is pivotally connected with the graphite boat 2, and a lock catch is arranged on the boat cover to close the graphite boat 2.

[0023] Specifically, the boat cover is connected with the graphite boat 2 through a high-temperature-resistant hinge to realize rotating connection, the boat cover can be flipped around the hinge, and the flexibility of opening and closing under high temperature is ensured. The graphite boat 2 can be loaded and inspected without disassembling the boat cover. The pre-tightening force of the lock catch makes the boat cover closely fit the edge of the graphite boat 2 to form a closed cavity, controls the oxygen content in the graphite boat 2, and avoids the graphite in the black powder leaching slag from being oxidized by contacting with air under high temperature. The lock catch is a clasp, the clasp can be hooked with the protrusion at the edge of the graphite boat 2, after the boat cover is flipped to cover the graphite boat 2, the clasp falls and is hooked with the protrusion to complete the fixation of the boat cover, and at this time the clasp is limited by the protrusion. After the graphite boat 2 is flipped by 180 degrees, the clasp is released from the protrusion, the boat cover is flipped to be opened, and the top of the graphite boat 2 is opened to pour out the contents.

[0024] Optionally, the lock catch can be an L-shaped claw, one end of the claw is arranged with a tooth to engage with the edge of the graphite boat 2, the claw is connected with the boat cover through a rotating shaft, a counterweight is arranged on the claw, and the counterweight is used to increase the gravity to assist the claw to overcome the friction between the tooth and the edge of the graphite boat 2 to complete the unlocking of the claw.

[0025] In some embodiments, a sieve plate is arranged in the graphite boat 2, and the sieve plate divides the internal cavity of the graphite boat 2 into at least two cavities in the thickness direction.

[0026] Specifically, the material accumulation in the graphite boat 2 causes the surface layer of the material to overheat and the bottom layer of the material to be incompletely pyrolyzed. The material accumulation causes the impurity gas to be unable to quickly escape, and the material is easily bonded into a block under high temperature.

[0027] The black powder leaching residue in the graphite boat 2 falls through the screen holes between the layers, achieving multiple stirring and dispersion, and avoiding uneven heating caused by local accumulation of black powder leaching residue. The screen plate can be made of silicon carbide or high-temperature alloy material, which should not chemically react with graphite / leaching residue to avoid introducing impurities. The size of the screen hole should be matched with the particle size of the black powder leaching residue to ensure smooth falling of the material without blocking the hole. The screen plate can be one layer or two layers, and too many layers will increase the resistance of the material falling, causing the material to stay for too long. The screen plate is installed horizontally inside the graphite boat 2, and the edge of the screen plate is clamped into the inner wall of the graphite boat 2 to avoid material falling from the gap between the screen plate and the wall, ensuring that the material must pass through the screen hole to be layered. When the graphite boat 2 rotates, the material in the upper cavity slides along the surface of the screen plate under the action of centrifugal force and gravity and falls through the screen hole into the lower cavity. When the graphite boat 2 is turned over 180 degrees, the material in the lower cavity falls through the screen hole in the opposite direction and finally falls into the conveying steel belt.

[0028] In some embodiments, the driving mechanism further includes an outer magnetic rotor and an inner magnetic rotor, the output end of the rotating motor 31 is connected to the outer magnetic rotor, one end of the rotating shaft 32 is connected to the inner magnetic rotor, and the outer magnetic rotor and the inner magnetic rotor are magnetically attracted to each other with the furnace wall of the pyrolysis furnace 1 in between.

[0029] Specifically, non-contact transmission is achieved through the cooperation of the outer magnetic rotor and the inner magnetic rotor, completely solving the problem of shaft seal leakage. The outer magnetic rotor is fixed to the output end of the rotating motor 31 and located outside the furnace wall of the pyrolysis furnace 1, and the inner magnetic rotor is fixed to one end of the rotating shaft 32 near the furnace wall and located inside the furnace wall of the pyrolysis furnace 1. The furnace wall of the pyrolysis furnace 1 does not affect the penetration of the magnetic field. When the outer magnetic rotor rotates with the motor, the magnetic field force drives the inner magnetic rotor to rotate synchronously, thereby driving the rotating shaft 32 and the graphite boat 2 to rotate. The outer magnetic rotor and the inner magnetic rotor are made of high-temperature-resistant magnets, and there is no physical contact between them, reducing wear and tear. When the raw materials in the graphite boat 2 are severely caked, causing excessive load, the inner magnetic rotor slips, achieving overload protection.

[0030] In some embodiments, the pyrolysis furnace 1 is provided with a return port 105 at the bottom, and the top surface of at least one conveying steel belt can move towards the return port 105.

[0031] Specifically, the return port 105 is precisely aligned with the end of the conveying steel belt at the bottom of the pyrolysis furnace 1 near the furnace wall, ensuring smooth introduction of the material. The return port 105 can send unqualified pyrolyzed materials out of the pyrolysis furnace 1 and reprocess the materials. Even with the screen plate layering and dispersion, some materials may not have completely removed organic impurities due to severe caking of raw materials, insufficient pyrolysis time, etc. The steel belt shunts the materials that have not been completely pyrolyzed, and the materials are returned for reprocessing, improving the overall recovery rate.

[0032] In some embodiments, at least two conveying steel belts are arranged in the pyrolysis furnace 1, the conveying steel belts are spaced apart in the vertical direction from the adjacent conveying steel belts by a distance and the top surface of the conveying steel belts moves in a direction opposite to the conveying direction of the adjacent conveying steel belts.

[0033] Specifically, the spacing apart of the two conveying steel belts in the vertical direction ensures that when the material falls from the upper steel belt to the lower steel belt, there is enough space to complete the free-fall dispersion, while avoiding too large a drop to cause the graphite particles to break or too much dust to be generated. The single steel belt can only achieve one-way conveying, and the material dispersion relies on its own gravity. The multi-layer steel belt can achieve reverse folding after falling and dispersion, prolong the residence time for more sufficient pyrolysis, and even if part of the material is not completely removed due to insufficient pyrolysis time, it can also be fully contacted with the high-temperature inert gas flow in the furnace during the folding process.

[0034] Optionally, the adjacent steel belts are misaligned in the horizontal direction to avoid the material falling vertically directly, prolong the residence path of the material on the steel belt, and improve the dispersion uniformity.

[0035] In some embodiments, the surface of the conveying steel belt is provided with anti-skid protrusions and a plurality of air permeable holes are uniformly arranged.

[0036] Specifically, the anti-skid protrusions arranged on the surface of the conveying steel belt increase the static friction between the conveying steel belt and the material after pyrolysis, and the air permeable holes open the hot gas flow channels above and below the steel belt, so that the high-temperature inert gas flow in the pyrolysis furnace 1 can penetrate the material layer, achieving up and down heating, and the impurity gas (such as organic volatile components) generated by the material pyrolysis can be quickly discharged through the air permeable holes.

[0037] In some embodiments, a pressure regulating mechanism is further included, the pressure regulating mechanism includes a pressure sensor, an electrically adjusted valve and an explosion-proof pressure relief valve, the explosion-proof pressure relief valve is arranged on the furnace body of the pyrolysis furnace 1, and the pressure sensor is electrically connected with the electrically adjusted valve on the pyrolysis gas outlet 103.

[0038] Specifically, the pressure in the furnace is set to be slightly positive, for example, in the range of 0.01-0.05 MPa, which prevents air from seeping in and is beneficial to the discharge of pyrolysis gas. The pressure sensor adopts a high-temperature capacitive sensor to feed back data in real time. When the pressure is higher than the set threshold, the electrically adjusted valve is controlled to increase the opening degree to accelerate the discharge of pyrolysis gas. When the pressure is lower than the set threshold, the electrically adjusted valve is controlled to reduce the opening degree to reduce the loss of inert gas and maintain the stability of the pressure. When the pressure in the furnace rises rapidly, the explosion-proof pressure relief valve is opened instantaneously to quickly release the overpressure gas, avoiding the overpressure of the furnace body. In this way, the inert atmosphere in the furnace can be stabilized to avoid the oxidation of graphite, and the safety of the equipment can be ensured to avoid the deformation of the furnace body, the failure of the seal and even the explosion caused by the sudden rise of the pressure in the furnace.

[0039] In some embodiments, a water-cooled jacket 5 is further included, which is arranged around the outside of the pyrolysis furnace 1.

[0040] Specifically, the water-cooled jacket 5 can take away the excess heat of the pyrolysis furnace 1 wall, both to avoid the wall deformation caused by over-temperature, and to stabilize the temperature field in the furnace. The waste heat of the heat exchange of the cooling water can be utilized. The cooling water of the water-cooled jacket 5 can flow spirally along the wall, avoiding local water flow dead angle leading to uneven cooling. The water-cooled jacket 5 stabilizes the wall temperature in a certain range to avoid equipment damage caused by over-temperature. The recovered waste heat can be used to preheat the inert gas entering the pyrolysis furnace 1.

[0041] In some embodiments, a coil pipe 6 is arranged on the conveying steel belt 4, which is coiled in the conveying steel belt 4 for heat transfer to make the upper surface temperature of the conveying steel belt 4 consistent with the lower surface temperature. A driving shaft and a driven shaft are arranged at both ends of the conveying steel belt 4 respectively to drive the conveying steel belt 4 to rotate. Here, the conveying steel belt 4 is arranged in a ring shape, and rotates circularly under the driving of the driving shaft and the driven shaft. The coil pipe 6 is fixed in an embedded manner in the ring-shaped space enclosed by the conveying steel belt 4, and heat conducting oil can be filled in the coil pipe 6.

[0042] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element 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.

[0043] In addition, the terms "first" and "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first" and "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise explicitly specified and limited.

[0044] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting", "fixing" and the like should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integral; can be mechanical connection, can also be electrical connection or communication with each other; can be directly connected, or indirectly connected through an intermediate medium; can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0045] In the present application, unless specifically stated and limited otherwise, a first feature is "on" or "under" a second feature can mean that the first and second features are in direct contact, or the first and second features are in indirect contact with an intervening medium. Also, a first feature "over", "above" and "on top of" a second feature can mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature. A first feature "under", "below" and "underneath" a second feature can mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is horizontally lower than the second feature.

[0046] In the present application, the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" mean that a particular feature, structure, material, or characteristic being described is included in at least one embodiment or example of the present application. The illustrative appearances of the above-mentioned terms in various places in the specification are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples. Moreover, the terms "first", "second", "third", etc. are used herein merely as identifiers for different elements, regions, or layers, and are not intended to be taken literally, unless otherwise specified.

[0047] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary, and are not to be taken in a limiting sense, and that variations, modifications, substitutions and alterations of the above-described embodiments are possible within the scope of the present application.

Claims

1. A pyrolysis device for recovering graphite from black powder leaching residue, characterized in that, include: The pyrolysis furnace comprises a pyrolysis furnace, a drive mechanism, and a conveying mechanism. The pyrolysis furnace has a graphite boat inside to hold graphite. The top of the pyrolysis furnace has an inert gas inlet, a raw material feeding port, and a pyrolysis gas outlet. The raw material feeding port is connected to a raw material buffer chamber. The bottom of the pyrolysis furnace has a graphite outlet. The drive mechanism passes through the pyrolysis furnace and is connected to the graphite boat to drive the graphite boat to rotate relative to the pyrolysis furnace. The conveying mechanism includes a conveying steel belt located below the graphite boat, and the top surface of the conveying steel belt is movable towards the graphite outlet.

2. The pyrolysis apparatus for recovering graphite from black powder leaching residue according to claim 1, characterized in that, The driving mechanism includes a rotary motor and a rotating shaft. The rotary motor is arranged on the outer wall of the pyrolysis furnace. One end of the rotating shaft is connected to the output end of the rotary motor, and the other end of the rotating shaft passes through the pyrolysis furnace and the graphite boat and is rotatably connected to the inner wall of the pyrolysis furnace.

3. The pyrolysis apparatus for recovering graphite from black powder leaching residue according to claim 2, characterized in that, The graphite boat has a cover on top, which is pivotally connected to the graphite boat, and the cover is provided with a latch to close the graphite boat.

4. The pyrolysis apparatus for recovering graphite from black powder leaching residue according to claim 3, characterized in that, The graphite boat is provided with a sieve plate, which divides the internal cavity of the graphite boat into at least two cavities in the thickness direction.

5. The pyrolysis apparatus for recovering graphite from black powder leaching residue according to claim 2, characterized in that, The drive mechanism further includes an outer magnetic rotor and an inner magnetic rotor. The output end of the rotating motor is connected to the outer magnetic rotor, and one end of the rotating shaft is connected to the inner magnetic rotor. The outer magnetic rotor and the inner magnetic rotor are magnetically attracted to each other across the furnace wall of the pyrolysis furnace.

6. The pyrolysis apparatus for recovering graphite from black powder leaching residue according to claim 1, characterized in that, The bottom of the pyrolysis furnace is provided with a return port, and the top surface of at least one of the conveyor steel belts can move toward the return port.

7. The pyrolysis apparatus for recovering graphite from black powder leaching residue according to claim 6, characterized in that, At least two of the conveyor belts are arranged inside the pyrolysis furnace, the conveyor belts being vertically spaced a certain distance from each other, and the top surface of the conveyor belts moving in the opposite direction to the transmission direction of the adjacent conveyor belts.

8. The pyrolysis apparatus for recovering graphite from black powder leaching residue according to claim 7, characterized in that, The surface of the conveyor belt is provided with anti-slip ridges and multiple air holes are evenly distributed.

9. The pyrolysis apparatus for recovering graphite from black powder leaching residue according to claim 1, characterized in that, It also includes a pressure regulating mechanism, which includes a pressure sensor, an electric regulating valve, and an explosion-proof pressure relief valve. The explosion-proof pressure relief valve is arranged on the furnace body of the pyrolysis furnace, and the pressure sensor is electrically connected to the electric regulating valve on the pyrolysis gas outlet.

10. The pyrolysis apparatus for recovering graphite from black powder leaching residue according to claim 1, characterized in that, It also includes a water-cooled jacket arranged around the exterior of the pyrolysis furnace.

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