Cathode graphite recovery system

Abstract

The utility model belongs to the technical field of battery cathode material recovery, and discloses a cathode graphite recovery system. The negative electrode graphite recovery system comprises a separation reaction kettle, a first centrifugal machine, an impurity removal reaction kettle, a second centrifugal machine and a waste liquid collection unit, the separation reaction kettle comprises a separation device and a separation kettle body, and the separation device is provided with a containing cavity, a first feeding port and a first discharging port; a second feeding hole of the first centrifugal machine is communicated with the first discharging hole, and a first liquid discharging hole is communicated with the waste liquid collecting unit; the impurity removal reaction kettle comprises a reaction kettle body, and a third feeding hole of the reaction kettle body is communicated with the second discharging hole; and a fourth feeding hole in the second centrifugal machine is communicated with the third discharging hole, and a second liquid discharging hole is communicated with the waste liquid collecting unit. According to the negative electrode graphite recovery system, the negative electrode plate and the graphite can be recovered respectively, the recovery efficiency of the graphite is improved, the purity of the obtained graphite is higher, and the treatment cost of recycling can be reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of battery negative electrode material recovery, in particular to a negative electrode graphite recovery system. Background Art

[0002] With the rapid development of lithium-ion battery industry, it is widely used in electronic products and new energy vehicles. As some lithium-ion batteries are approaching the end of their service life, the number of waste lithium-ion batteries is increasing sharply. As a result, the treatment of waste lithium-ion batteries, especially waste graphite negative electrodes of batteries, is becoming increasingly prominent.

[0003] At present, there are many ways to deal with waste graphite negative electrodes, mainly incineration, landfill, recycling and reuse, etc. Among them, incineration and landfill will not only cause waste of resources, but also cause serious pollution to the environment. The recycling and reuse of waste graphite negative electrodes can not only reduce resource waste, but also reduce the pollution of negative electrode materials to the environment, and at the same time save the mining and production costs of raw materials, which is of great significance for achieving sustainable development.

[0004] However, the existing recycling technology for waste graphite negative electrode materials is not mature. The commonly used methods are strong acid leaching and surface carbon coating modification. The regeneration process will produce a large amount of wastewater and waste acid, which is difficult to promote industrially. Utility Model Content

[0005] The utility model aims to provide a negative electrode graphite recovery system, which can improve the recovery efficiency and purity of graphite. Furthermore, the system can reuse waste liquid and reduce the recovery cost.

[0006] To achieve this purpose, the utility model adopts the following technical solutions:

[0007] The negative electrode graphite recovery system is used for the recovery of waste negative electrode graphite, and comprises a separation reactor, a first centrifuge, an impurity removal reactor, a second centrifuge and a waste liquid collection unit, wherein: the separation reactor comprises a separation reactor body, a separation device and a water inlet pipe, the separation device is arranged in the separation reactor body, the separation device is provided with a holding chamber for accommodating the waste negative electrode graphite, and a first feed port and a first discharge port communicated with the holding chamber, the water inlet pipe is used to supply liquid to the holding chamber; the first centrifuge is provided with a second feed port, a second discharge port and a first liquid discharge port, the The second feed port is communicated with the first discharge port, and the first liquid discharge port is communicated with the waste liquid collection unit; the impurity removal reactor comprises a reactor body, and the reactor body is provided with a third feed port, a third discharge port and at least one liquid injection port, the third feed port is communicated with the second discharge port, and the liquid injection port is used to supply a solvent that can dissolve impurities in the waste negative electrode graphite; the second centrifuge is provided with a fourth feed port, a fourth discharge port and a second liquid discharge port, the fourth feed port is communicated with the third discharge port, and the second liquid discharge port is communicated with the waste liquid collection unit.

[0008] Optionally, the waste liquid collection unit includes a first waste liquid barrel, a second waste liquid barrel and a third waste liquid barrel, the third waste liquid barrel is connected to the water inlet pipe; the first discharge port of the first centrifuge is connected to the first waste liquid barrel; the second discharge port of the second centrifuge is connected to the second waste liquid barrel and the third waste liquid barrel respectively.

[0009] Optionally, the above-mentioned separation device includes a water barrel, a deliquescence barrel and an agitator, the above-mentioned accommodating chamber is located in the above-mentioned deliquescence barrel, the above-mentioned deliquescence barrel is arranged in the above-mentioned water barrel, and there is a gap between the above-mentioned deliquescence barrel and the above-mentioned water barrel, the above-mentioned agitator can act on the above-mentioned waste negative electrode graphite in the above-mentioned deliquescence barrel, and the wall surface of the above-mentioned deliquescence barrel is provided with a plurality of dehydration holes.

[0010] Optionally, the first discharge port is arranged at the bottom of the water tank.

[0011] Optionally, the water inlet pipe is arranged above the separation device.

[0012] Optionally, an ultrasonic generating device is provided on the outer wall of the water tub.

[0013] Optionally, a first heater is provided on the water inlet pipe.

[0014] Optionally, the wall surface of the dehydration barrel is covered with a first screen, the aperture of the first screen is 350-500 mesh, and the aperture of the first screen is smaller than the aperture of the dehydration hole.

[0015] Optionally, the first centrifuge and the second centrifuge both include a centrifuge body, and a filter screen, a scraper and a washing pipe arranged in the centrifuge body, there is a gap between the filter screen and the centrifuge body, the scraper and the washing pipe are located in the filter screen, and the scraper is used to scrape off attachments on the inner wall of the filter screen.

[0016] Optionally, the first centrifuge and the second centrifuge each further include a discharge valve and a discharge bin sequentially disposed below the centrifuge body, and the discharge bin of the first centrifuge is connected to the third feed port of the impurity removal reactor.

[0017] Optionally, a material level detector is further provided in the centrifuge body, and the material level detector is used to detect the thickness of the attachments on the inner wall of the filter.

[0018] Optionally, the impurity removal reactor further comprises a stirrer, a second heater and a temperature sensor, the stirrer is arranged in the reactor body, the second heater is arranged on the reactor wall of the reactor body, and the temperature sensor is used to detect the temperature in the reactor body.

[0019] Optionally, the impurity removal reactor further comprises a heat-insulating layer surrounding the reactor body.

[0020] Optionally, the above-mentioned liquid injection port is provided in plurality, each used for supplying a different solvent.

[0021] Beneficial effects:

[0022] The negative electrode graphite recovery system of the utility model firstly separates the graphite from the waste negative electrode graphite by vibration through the separation reactor, and takes the graphite to the first centrifuge downstream, at which time the waste negative electrode sheets can be recovered, the first centrifuge rotates to filter and dry the graphite, and the liquid is poured into the waste liquid collection unit, and then the dried graphite is rinsed and flows into the downstream de-impurity reactor, and the solvent for dissolving impurities is poured into the de-impurity reactor, so as to remove impurities in the graphite and purify the graphite, and then the solvent and the graphite flow into the second centrifuge downstream, the second centrifuge dry the graphite through centrifugal action, and the generated waste liquid is collected in the waste liquid collection unit, and then the graphite is rinsed and repeatedly dried, and the waste liquid generated by drying can be passed into the separation reactor for repeated use. The negative electrode graphite recovery system can separate waste negative electrode graphite and recover negative electrode sheets and graphite separately. The entire process can be operated automatically, which improves the graphite recovery efficiency. The obtained graphite has higher purity. In addition, part of the waste liquid can be recycled and reused, which can reduce the processing cost of recycling. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1It is a schematic diagram of a negative electrode graphite recovery system provided by a specific embodiment of the utility model.

[0024] In the figure:

[0025] 100, separation reaction kettle; 110, water storage bucket; 120, dehydration bucket; 130, stirrer; 140, ultrasonic generator; 150, first heater; 160, water inlet pipe;

[0026] 200, first centrifuge; 201, first washing device; 202, first liquid discharge port; 203, material level detector; 210, centrifuge body; 220, scraper; 230, discharge valve; 240, discharge bin;

[0027] 300, impurity removal reactor; 310, reactor body; 320, mixer; 330, second heater; 340, insulation layer; 350, temperature sensor; 360, liquid injection port;

[0028] 400, second centrifuge; 401, second washing device; 402, second liquid discharge port;

[0029] 500, waste liquid collection unit; 511, first waste liquid barrel; 512, second waste liquid barrel; 513, third waste liquid barrel; 521, first magnetic pump; 522, second magnetic pump; 523, third magnetic pump. DETAILED DESCRIPTION

[0030] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only the parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0031] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0033] In the description of this embodiment, the terms "upper", "lower", "right", etc., are based on the directions or positions shown in the drawings, and are only for the convenience of description and simplified operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0034] Please refer to Figure 1 In this embodiment, the negative electrode graphite recovery system is used for the recovery of waste negative electrode graphite, including a separation reactor 100, a first centrifuge 200, an impurity removal reactor 300, a second centrifuge 400 and a waste liquid collection unit 500, wherein: the separation reactor 100 includes a separation reactor body, a separation device and a water inlet pipe 160, the separation device is arranged in the separation reactor body, the separation device is provided with a receiving chamber for accommodating the waste negative electrode graphite, and a first feed port and a first discharge port connected to the receiving chamber, the water inlet pipe 160 is used to supply liquid to the receiving chamber; the first centrifuge 200 is provided with a second feed port, a second discharge port and a first liquid discharge port 202 , the second feed port is connected to the first discharge port, and the first drainage port 202 is connected to the waste liquid collection unit 500; the impurity removal reactor 300 includes a reactor body 310, and the reactor body 310 is provided with a third feed port, a third discharge port and at least one injection port 360, the third feed port is connected to the second discharge port, and the injection port 360 is used to supply a solvent that can dissolve impurities in the waste negative electrode graphite; the second centrifuge 400 is provided with a fourth feed port, a fourth discharge port and a second drainage port 402, the fourth feed port is connected to the third discharge port, and the second drainage port 402 is connected to the waste liquid collection unit 500.

[0035] The negative electrode graphite recovery system in this embodiment firstly vibrates and separates the graphite from the waste negative electrode graphite through the separation reactor 100, and uses a cleaning liquid to carry the graphite to the first centrifuge 200 downstream, at which time the waste negative electrode sheets can be recovered, and the first centrifuge 200 rotates so that the graphite is filtered and dried, and the liquid is poured into the waste liquid collection unit 500, and then the dried graphite flows into the downstream decontamination reactor 300, and a solvent for dissolving impurities is poured into the decontamination reactor 300, so as to remove impurities in the graphite and purify the graphite, and then the graphite flows into the downstream second centrifuge 400 together with the solvent and graphite, and the second centrifuge 400 dries the graphite by centrifugal action, and the generated waste liquid is collected in the waste liquid collection unit 500, and then the graphite is rinsed and repeatedly dried, and the waste liquid generated by drying can be passed into the separation reactor 100 for reuse. The negative electrode graphite recovery system can separate waste negative electrode graphite and recover negative electrode sheets and graphite separately. The entire process can be operated automatically, which improves the graphite recovery efficiency. The obtained graphite has higher purity. In addition, part of the waste liquid can be recycled and reused, which can reduce the processing cost of recycling.

[0036] The separation reactor 100 in the present invention can be, for example, a pulsator cleaning machine (such as a pulsator washing machine), an ultrasonic cleaning machine, or a cleaning machine combining ultrasonic and pulsator. The first centrifuge 200 and the second centrifuge 400 can be, for example, fully automatic scraper unloading centrifuges, and the impurity removal reactor 300 can be, for example, a paddle-type stirring stainless steel reactor, which is not specifically limited here.

[0037] Please continue to refer to Figure 1 Optionally, the separation device includes a water barrel 110, a dehydration barrel and an agitator 130, the accommodating chamber is located in the dehydration barrel, the dehydration barrel is arranged in the water barrel 110, and there is a gap between the dehydration barrel and the water barrel 110, the agitator 130 can act on the waste negative electrode graphite in the dehydration barrel, and the wall of the dehydration barrel is provided with a plurality of dehydration holes. The separation reactor 100 in this embodiment uses the agitator 130 to stir the mixture of the cleaning liquid and the waste negative electrode graphite. Driven by the cleaning liquid, the graphite flows into the gap between the dehydration barrel 120 and the water barrel 110, while the large pieces of negative electrode sheets are blocked by the dehydration holes and remain in the dehydration barrel 120, thereby improving the purity of the collected graphite, thereby simplifying the subsequent processing flow and improving the collection efficiency.

[0038] In this embodiment, the first discharge port is arranged at the bottom of the water barrel 110; the first discharge port arranged in this way is more in line with the trend and direction of liquid flow, ensuring that the liquid containing graphite is discharged from the water barrel 110 as much as possible, thereby improving the collection efficiency.

[0039] Optionally, the water inlet pipe 160 is arranged above the separation device; the water inlet pipe 160 is arranged above the separation device, which is convenient for introducing cleaning liquid into the separation reactor 100. Further, without being bound by theory, the impact force of the water flow can be used to flush the waste negative electrode graphite, thereby further improving the separation efficiency of graphite and waste negative electrode.

[0040] Furthermore, an ultrasonic generator 140 may be provided on the outer wall of the water storage tub 110; the ultrasonic generator 140 uses ultrasonic waves to vibrate the waste negative electrode graphite, thereby separating the graphite from the negative electrode sheet, and further improving the separation efficiency. The ultrasonic generator in the present invention may be a commercially available product, and the location of the ultrasonic generator 140 may also be adjusted as needed, which is not limited here.

[0041] Furthermore, the water inlet pipe 160 may be sleeved with a first heater 150; the first heater 150 can heat the liquid flowing into the separation reactor 100 through the water inlet pipe 160, thereby making it easier for graphite to be separated from the negative electrode sheet, thereby shortening the separation time. The first heater 150 in the present invention may be, for example, a commercially available resistive electric heater, which is wrapped or sleeved on the water inlet pipe 160, and is not limited here.

[0042] Furthermore, a first screen is provided on the wall of the dehydration barrel, the specification of the first screen is 350 mesh to 500 mesh, and the aperture of the first screen is smaller than the aperture of the dehydration hole. The first screen can also block larger negative electrode sheets and fragments of negative electrode sheets to prevent them from flowing into the downstream processing system, thereby further improving the purity of the collected graphite and improving the collection efficiency.

[0043] In this embodiment, the first centrifuge 200 and the second centrifuge 400 both include a centrifuge body 210, and a filter screen, a scraper 220 and a washing pipe arranged in the centrifuge body 210. There is a gap between the filter screen and the centrifuge body 210. The scraper and the washing pipe are located in the filter screen. The scraper is used to scrape off the attachments on the inner wall of the filter screen. Specifically, the washing pipe of the first centrifuge 200 is the first washing device 201 here, and the washing pipe of the second centrifuge 400 is the second washing device 401 here; the first washing device 201 or the second washing device 401 is used in conjunction with the scraper 220 to scrape off and clean the graphite attached to the filter screen in the centrifuge body 210 as much as possible, collect graphite as much as possible, and have a higher recovery rate.

[0044] like Figure 1As shown, the centrifuge body 210 is provided with a material level detector 203, and the material level detector 203 is used to detect the thickness of the attachments on the inner wall of the filter. The material level detector 203 can detect the thickness of the attachments on the filter to prevent the material from being overweight when the equipment is running; and when the material reaches a certain thickness, the first centrifuge 200 and the second centrifuge 400 start to run at high speed to dry the graphite, which improves the collection efficiency, does not cause energy waste, and reduces the cost of graphite recovery. The material level detector 203 in the present invention can adopt, for example, a commercially available ultrasonic material level sensor, a capacitive material level sensor, etc., which is not limited here.

[0045] Further, a discharge valve 230 is provided below the centrifuge body 210 of the first centrifuge 200 and the second centrifuge 400, and a discharge bin 240 is provided downstream of the discharge valve 230. The discharge bin 240 of the first centrifuge 200 is connected to the impurity removal reactor 300. The discharge valve 230 is specifically a pneumatic valve, which generates negative pressure to suck graphite into the discharge bin 240 below, thereby completing the collection and discharge of graphite, and the working efficiency is higher.

[0046] Please continue to refer to Figure 1 The impurity removal reactor 300 includes a reactor body 310, a stirrer 320 and a second heater 330. The stirrer 320 is disposed in the reactor body 310, and the second heater 330 is disposed on the reactor wall of the reactor body 310. The second heater 330 can be disposed on the inner wall or outer wall of the reactor body 310, and no specific limitation is made here. After the solvent is introduced into the reactor body 310, the second heater 330 is turned on to heat the solvent in the reactor body 310, so that the impurities in the graphite are fully dissolved, leaving only graphite particles, thereby improving the purity of the recovered graphite.

[0047] In this embodiment, the reactor body 310 is further provided with a heat-insulating layer 340 , which surrounds the reactor body 310 , and is used to insulate the solvent in the reactor body 310 , thereby reducing energy loss during heating by the second heater 330 .

[0048] Furthermore, the reactor body 310 is provided with a plurality of injection ports 360, which are used to introduce a plurality of solvents for dissolving impurities one by one. Due to the different types of impurities, different types of solvents can be introduced through a plurality of injection ports 360 to completely dissolve the impurities in the graphite, thereby further improving the purity of the graphite.

[0049] In this embodiment, the above-mentioned waste liquid collection unit 500 includes a first waste liquid barrel 511, a second waste liquid barrel 512 and a third waste liquid barrel 513, and the above-mentioned third waste liquid barrel 513 is connected to the above-mentioned water inlet pipe 160; the above-mentioned first discharge port 202 of the above-mentioned first centrifuge 200 is connected to the above-mentioned first waste liquid barrel 511; the above-mentioned second discharge port 402 of the above-mentioned second centrifuge 400 is connected to the above-mentioned second waste liquid barrel 512 and the above-mentioned third waste liquid barrel 513 respectively. Specifically, the first liquid discharge port 202 is connected to the first waste liquid barrel 511, and the waste liquid is pumped into the first waste liquid barrel 511 through the first magnetic pump 521; a second magnetic pump 522 is provided downstream of the second liquid discharge port 402, so as to pump the waste liquid into the second waste liquid barrel 512 or the third waste liquid barrel 513; a third magnetic pump 523 is provided between the third waste liquid barrel 513 and the water inlet pipe 160 of the separation reactor 100, so as to pump the waste liquid in the third waste liquid barrel 513 into the separation reactor 100 for reuse. By collecting and reusing the waste liquid separately, the wastewater treatment amount and difficulty are reduced, and the cost is reduced.

[0050] The following is a detailed description of the working process of the negative electrode graphite recovery system:

[0051] First, the separation reactor 100 is opened, and the recycled waste negative electrode graphite is put into the dehydration barrel 120 of the separation reactor 100. There are dehydration holes on the wall of the dehydration barrel 120, and a first screen with a mesh size of 350 to 500 is provided. Then, the separation reactor 100 is closed, and water is poured into the reactor. The cold water is heated by the first heater 150 and enters the water bucket 110 in the reactor through the water inlet pipe 160. The stirrer 130 starts stirring at a low speed, and the ultrasonic generator 140 is turned on to separate the graphite from the electrode piece. Then, the stirrer 130 starts to run at a high speed, so that the liquid with graphite is discharged and enters the first centrifuge 200. At the same time, the first centrifuge 200 starts to run at a low speed, and the mesh size of the filter bag in the first centrifuge 200 is greater than 1500 mesh.

[0052] After the liquid in the separation reactor 100 is drained, water is continuously injected and the ultrasonic generator 140 and the stirrer 130 are turned on for stirring 2 to 3 times to recover as much graphite as possible; and only the pole pieces are left in the separation reactor 100, which can be recycled.

[0053] The material level detector 203 in the first centrifuge 200 detects the thickness of the material on the filter screen in the centrifuge body 210 to prevent the material from being overweight when the equipment is running, and stops feeding when the material reaches a certain thickness. Then the first centrifuge 200 starts to run at high speed to dry the graphite, and the generated waste liquid is discharged through the drain port and then pumped into the first waste liquid barrel 511 through the first magnetic pump 521 to collect the waste liquid.

[0054] After the graphite material in the first centrifuge 200 is dried, the material is scraped off by the scraper 220. After scraping, the first washing device 201 is opened to rinse the inner wall of the centrifuge body 210. After the graphite is completely rinsed off, the pneumatic valve is opened to allow the graphite to enter the discharge bin 240 and then enter the impurity removal reactor 300.

[0055] At this time, different injection ports 360 are opened, different solvents are injected into the decontamination reactor 300, and the agitator 320 and the second heater 330 are turned on to fully dissolve the impurities in the graphite in the solvent, wherein the temperature sensor 350 is used to monitor the temperature in the decontamination reactor 300, and the insulation layer 340 is used to reduce energy loss. After the dissolution reaction is completed, the graphite material is discharged through the discharge port into the second centrifuge 400, and the second centrifuge 400 starts to run at a low speed, and the waste liquid is discharged through the second discharge port 402 and pumped into the second waste liquid barrel 512 through the second magnetic pump 522.

[0056] After the materials in the decontamination reactor 300 are discharged, the second centrifuge 400 starts to run at high speed to dry the materials; then the second washing device 401 injects water into the centrifuge body 210 of the second centrifuge 400, and the second centrifuge 400 starts to run at a low speed. After a certain period of time, the water injection is stopped, and the materials are dried by high-speed operation. This is repeated 3-4 times, and the waste water generated by the water washing is pumped into the third waste water bucket through the second magnetic pump 522; the waste water in the third waste water bucket can be reused and pumped into the separation reactor 100 through the third magnetic pump 523.

[0057] Finally, after the water washing in the second centrifuge 400 is completed, the scraper 220 of the second centrifuge 400 scrapes off the graphite material, opens the pneumatic valve, and the graphite material enters the discharge bin 240 of the second centrifuge 400. Finally, the graphite material is collected and dried and used again in actual battery production to achieve graphite recycling.

[0058] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the scope of protection of the present invention. It is not necessary and impossible to list all implementation methods here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the scope of protection of the claims of the present invention.

Claims

1. Negative electrode graphite recovery system, used for the recovery of waste negative electrode graphite, characterized in that: The invention comprises a separation reaction kettle (100), a first centrifuge (200), a decontamination reaction kettle (300), a second centrifuge (400) and a waste liquid collection unit (500), wherein: The separation reaction kettle (100) comprises a separation kettle body, a separation device and a water inlet pipe (160), wherein the separation device is arranged in the separation kettle body, the separation device is provided with a receiving chamber for receiving the waste negative electrode graphite, and a first feed port and a first discharge port communicated with the receiving chamber, and the water inlet pipe (160) is used to supply liquid to the receiving chamber; The first centrifuge (200) is provided with a second feed port, a second discharge port and a first liquid discharge port (202), the second feed port is connected to the first discharge port, and the first liquid discharge port (202) is connected to the waste liquid collection unit (500); The de-impurity reactor (300) comprises a reactor body (310), the reactor body (310) is provided with a third feed port, a third discharge port and at least one liquid injection port (360), the third feed port is connected to the second discharge port, and the liquid injection port is used to supply a solvent that can dissolve impurities in the waste negative electrode graphite; The second centrifuge (400) is provided with a fourth feed port, a fourth discharge port and a second liquid discharge port (402), the fourth feed port is connected to the third discharge port, and the second liquid discharge port (402) is connected to the waste liquid collection unit (500).

2. The negative electrode graphite recovery system according to claim 1, characterized in that: The waste liquid collection unit (500) comprises a first waste liquid barrel (511), a second waste liquid barrel (512) and a third waste liquid barrel (513), and the third waste liquid barrel (513) is connected to the water inlet pipe (160); The first liquid discharge port (202) of the first centrifuge (200) is in communication with the first waste liquid bucket (511); The second liquid discharge port (402) of the second centrifuge (400) is connected to the second waste liquid barrel (512) and the third waste liquid barrel (513) respectively.

3. The negative electrode graphite recovery system according to claim 1, characterized in that: The separation device comprises a water-containing barrel (110), a deliquescence barrel (120) and an agitator (130); the accommodating chamber is located in the deliquescence barrel (120); the deliquescence barrel (120) is arranged in the water-containing barrel (110), and a gap is provided between the deliquescence barrel (120) and the water-containing barrel (110); the agitator (130) can act on the waste negative electrode graphite in the deliquescence barrel (120); and a plurality of dehydration holes are provided on the wall surface of the deliquescence barrel (120).

4. The negative electrode graphite recovery system according to claim 3, characterized in that: The first discharge port is arranged at the bottom of the water tank (110); And / or, the water inlet pipe (160) is arranged above the separation device; And / or, an ultrasonic generating device (140) is provided on the outer wall of the water holding tub (110); And / or, the water inlet pipe (160) is provided with a first heater (150); And / or, the wall surface of the dehydration barrel (120) is covered with a first screen, the aperture of the first screen is 350-500 mesh, and the aperture of the first screen is smaller than the aperture of the dehydration hole.

5. The negative electrode graphite recovery system according to claim 1, characterized in that: The first centrifuge (200) and the second centrifuge (400) both comprise a centrifuge body (210), and a filter screen, a scraper (220) and a washing pipe arranged in the centrifuge body (210), wherein a gap is provided between the filter screen and the centrifuge body (210), the scraper (220) and the washing pipe are located in the filter screen, and the scraper is used to scrape off attachments on the inner wall of the filter screen.

6. The negative electrode graphite recovery system according to claim 5, characterized in that: The first centrifuge (200) and the second centrifuge (400) also each include a discharge valve (230) and a discharge bin (240) sequentially arranged below the centrifuge body (210); the discharge bin (240) of the first centrifuge (200) is connected to the third feed port of the impurity removal reactor (300).

7. The negative electrode graphite recovery system according to claim 5, characterized in that: A material level detector (203) is also provided in the centrifuge body (210), and the material level detector (203) is used to detect the thickness of the attachments on the inner wall of the filter screen.

8. The negative electrode graphite recovery system according to claim 1, characterized in that: The impurity removal reactor (300) further comprises a stirrer (320), a second heater (330) and a temperature sensor (350); the stirrer (320) is arranged in the reactor body (310); the second heater (330) is arranged on the reactor wall of the reactor body (310); and the temperature sensor (350) is used to detect the temperature in the reactor body (310).

9. The negative electrode graphite recovery system according to claim 8, characterized in that: The impurity removal reactor (300) further comprises a heat-insulating layer surrounding the reactor body (310).

10. The negative electrode graphite recovery system according to claim 8, characterized in that: The liquid injection ports (360) are provided in plurality, each of which is used to supply a different solvent.

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