CN117154277A - Recovery system and method for separating black powder from waste lithium batteries - Google Patents

Recovery system and method for separating black powder from waste lithium batteries Download PDF

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Publication number
CN117154277A
CN117154277A CN202311422055.7A CN202311422055A CN117154277A CN 117154277 A CN117154277 A CN 117154277A CN 202311422055 A CN202311422055 A CN 202311422055A CN 117154277 A CN117154277 A CN 117154277A
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China
Prior art keywords
pyrolysis
pyrolysis reactor
flue gas
rotating shaft
reactor
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CN202311422055.7A
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CN117154277B (en
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陈水渺
孙宝林
赵延兵
王东方
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Golden Harvest Energy Beijing Technology Co ltd
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Golden Harvest Energy Beijing Technology Co ltd
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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/54Reclaiming serviceable parts of waste accumulators
    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01BNON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00Carbon; Compounds thereof
    • C01B32/20Graphite
    • C01B32/21After-treatment
    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01DCOMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
    • C01D15/00Lithium compounds
    • C01D15/08Carbonates; Bicarbonates
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02WCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00Technologies for solid waste management
    • Y02W30/50Reuse, recycling or recovery technologies
    • Y02W30/84Recycling of batteries or fuel cells

Abstract

The application relates to the technical field of pyrolysis of waste lithium batteries, in particular to a recovery system for separating black powder from waste lithium batteries and a recovery method thereof, wherein the recovery system comprises a pyrolysis system and a screening system, and the pyrolysis system comprises pyrolysis reactor main body equipment and smoke heating equipment; the main body equipment of the pyrolysis reactor comprises the pyrolysis reactor and a rotating shaft rotatably connected inside the pyrolysis reactor, wherein cleaning mechanisms are equidistantly arranged on the rotating shaft and can be in flexible contact with the inner wall of the pyrolysis reactor; the flue gas heating equipment is arranged at the periphery of the pyrolysis reactor, hot flue gas is provided for indirectly heating the pyrolysis reactor, and a flue gas outlet of the flue gas heating equipment is provided with a temperature sensor. By adopting the recovery system and the recovery method, the black powder can be recovered from the pyrolysis solid of the waste lithium battery, so that the yield of the black powder subjected to primary screening is obviously improved.

Description

Recovery system and method for separating black powder from waste lithium batteries
Technical Field
The application relates to the technical field of recycling of waste lithium batteries, in particular to a recovery system for separating black powder from waste lithium batteries and a recovery method thereof.
Background
The recovery treatment of the waste lithium batteries is the most popular research direction in the new energy industry. The way for recycling valuable components of the waste lithium batteries can be divided into two major categories, namely hydrometallurgy and pyrometallurgy. Hydrometallurgy mainly converts the anode material into salt through acid leaching/alkaline leaching/bioleaching/electrochemical deposition and other processes; the process of recycling the waste lithium battery black powder by adopting the pyrogenic process is approximately as follows: the battery pack is disassembled into modules, crushed and separated for one to three times, and large-block diaphragms and plastics are selected. Organic substances such as PVDF (polyvinylidene fluoride) and plastics in the adhesive in the lithium battery are pyrolyzed by a vacuum furnace, and then pyrolysis products are scattered, and black powder attached to the copper-aluminum foil pole piece is separated by sieving.
At present, conventional pyrolysis equipment for lithium batteries is mainly a rotary kiln pyrolysis reactor, but rotary kiln pyrolysis cannot be continuously operated, and has various technical defects such as low heat efficiency, high maintenance difficulty, poor air tightness, uneven material heating, high yield of black powder obtained by multi-stage screening when black powder is recovered from pyrolysis solids, and high impurity content of the black powder obtained by primary screening.
Therefore, a recovery system and a recovery method for separating black powder from waste lithium batteries are provided.
Disclosure of Invention
The application aims to provide a recovery system and a recovery method for separating black powder from waste lithium batteries, which adopt charged crushing and pyrolysis to realize the recovery of the black powder from the waste batteries with high yield. In the pyrolysis stage, the system and the method of the application fully remove the electrolyte, the plastic diaphragm and the like, and separate the black powder, the copper, the aluminum and other materials into pyrolysis solids. When the black powder is recovered from the pyrolysis solid obtained by the pyrolysis system, the primary screening process is simple, the time is short, the yield of the black powder is high, and the impurity content can be controlled at a lower level.
In order to achieve the above object, in one aspect, the present application provides the following technical solutions:
a recovery system for separating black powder from waste lithium batteries, the recovery system comprising a pyrolysis system and a sieving system, the pyrolysis system comprising pyrolysis reactor main body equipment and heating equipment;
the main pyrolysis reactor equipment comprises a pyrolysis reactor 2 and a rotating shaft 24 rotatably connected inside the pyrolysis reactor 2, wherein two ends of the rotating shaft 24 extend to the pyrolysis reactor 2, the rotating joint of the pyrolysis reactor 2 and the rotating shaft 24 is sealed, and one end of the rotating shaft 24 is provided with a driving piece;
the cleaning mechanisms 3 are equidistantly arranged on the rotating shaft 24, and the cleaning mechanisms 3 can be in flexible contact with the inner wall of the pyrolysis reactor 2;
the upper side of the outside of the pyrolysis reactor 2 is provided with a feed inlet 21, and the lower side of the outside of the pyrolysis reactor 2 is provided with a discharge outlet 23;
heating equipment is arranged at the periphery of the pyrolysis reactor and is used for indirectly heating the pyrolysis reactor,
the screening system comprises a grinding device and a screening device, wherein the grinding device and the screening device are used for grinding and screening pyrolysis solids, and the mesh size of the screening device is 100-150 meshes.
In one embodiment, the cleaning mechanisms 3 are equidistantly arranged along the length direction of the rotating shaft 24, and are staggered in the circumferential direction of the rotating shaft 24.
In one embodiment, the cleaning mechanism 3 comprises a connecting rod 31 fixedly connected with the rotating shaft 24, a movable inner tube 36 is vertically fixed at one end of the connecting rod 31 far away from the rotating shaft 24, two ends of the movable inner tube 36 are sleeved and rotatably connected with a movable outer tube 35, a scraper 32 is fixed at the outer part of the movable outer tube 35,
one end of the scraping plate 32 is fixed with a balancing weight 34, the other end of the scraping plate 32 is of an arc-shaped structure design, and the arc can be attached to the inner wall of the pyrolysis reactor 2;
and a limit stop 33 with an arc structure is fixed at the upper end of the connecting rod 31 near the movable inner tube 36 and is used for adjusting the inclination angle of the scraping plate 32.
In one embodiment, the heating device is a flue gas heating device, and comprises a flue gas heating box 1, wherein the upper side and the lower side of the flue gas heating box 1 are provided with communication ports, and the two communication ports are distributed relatively.
In one embodiment, two or more groups of cleaning mechanisms 3 are arranged on the rotating shaft 24, and the included angles of two adjacent groups of cleaning mechanisms 3 in the circumferential direction of the rotating shaft 24 are the same, and the included angles are 30-180 degrees.
In one embodiment, the pyrolysis system comprises a two or more stage pyrolysis reactor body apparatus, a two or more stage flue gas heating apparatus,
the main body equipment of each stage of pyrolysis reactor is matched with primary flue gas heating equipment; or two or more pyrolysis reactor main body devices share one flue gas heating device;
wherein, the pyrolysis reactor discharge outlet 23 of the main pyrolysis reactor device of the upper stage is communicated with the pyrolysis reactor feed inlet 21 of the main pyrolysis reactor device of the lower stage.
On the other hand, the application provides a recovery method for separating black powder from waste lithium batteries, which comprises the following steps:
carrying out charged crushing on the waste lithium batteries, and protecting inert gas in the crushing process;
the crushed raw materials are sent into a pyrolysis reactor 2, the pyrolysis reactor 2 is indirectly heated through heating equipment, and pyrolysis reaction is carried out to obtain pyrolysis gas and pyrolysis solids;
the temperature of the pyrolysis reaction is 350-450 ℃, and the residence time of the raw materials in the pyrolysis reactor is 20-60min;
and grinding and sieving the pyrolysis solid to obtain black powder, wherein the grinding time is 10-15min, and sieving the black powder by a 100-150 mesh sieve.
In one embodiment, the yield of black powder is greater than 98%, even greater than 99%, even greater than 99.5% after milling and sieving the pyrolyzed solids.
In one embodiment, the inert gas is nitrogen, and the size of the crushed waste lithium batteries is between 1 cm and 3cm.
In one embodiment, the flue gas heating apparatusThe flow rate of the flue gas is controlled to be 3000-5000Nm 3 In the range of/h.
In one embodiment, the flue gas heating device has a flue gas inlet temperature in the range of 500-700 ℃ and a flue gas outlet temperature in the range of 250-300 ℃.
In one embodiment, the temperature fluctuation at the flue gas outlet is controlled to be within 50 ℃.
In one embodiment, the pyrolysis solids after milling have a particle size of less than 2mm.
In one embodiment, the heating device is an electromagnetic heating device, wherein the electromagnetic heating device has a power in the range of 500-1000kw.
Compared with the prior art, the application has the beneficial effects that:
1. the application adopts a specific pyrolysis technology, and can obtain the black powder from the waste lithium battery with high yield. After the waste lithium battery is treated by the pyrolysis system, the electrolyte, the plastic diaphragm, PVDF and the like are effectively removed, so that adhesion between black powder and copper and aluminum is reduced during subsequent separation; the obtained pyrolysis solid is subjected to short-time grinding and primary screening to obtain high-yield black powder, wherein the copper content in the black powder is controlled below 0.40 wt% and the aluminum content is controlled below 0.30 wt%;
2. according to the application, through the design of the cleaning mechanism, the material turning shovel in the pyrolysis reactor can be facilitated, the pyrolysis reactor can be fully heated and decomposed, meanwhile, the movement and displacement of the internal materials are facilitated, and the scraping plate designed in the cleaning mechanism can be used for better scraping and cleaning attachments on the inner wall of the pyrolysis reactor, so that the pyrolysis reactor is beneficial to fully pyrolyzing and decomposing a battery diaphragm and PVDF, and is beneficial to fully grinding and sieving black powder subsequently.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present application, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic view of the overall structure of a pyrolysis system according to the present application;
FIG. 2 is an overall structural elevation view of the pyrolysis system of the present application;
FIG. 3 is a cross-sectional view showing the overall structure of the pyrolysis reactor body apparatus of the present application;
FIG. 4 is a cross-sectional view showing the overall structure of the pyrolysis reactor body apparatus of the present application;
FIG. 5 is a structural view of the cleaning mechanism of the present application;
FIG. 6 is a symmetrical distribution view of the cleaning mechanism of the present application;
FIG. 7 is a schematic view of a cleaning mechanism according to the present application;
FIG. 8 is a schematic diagram of a two-stage pyrolysis system according to the present application.
Reference numerals illustrate:
1. a heating device; 2. a pyrolysis reactor; 21. a feed inlet; 22. a motor; 23. a discharge port; 24. a rotation shaft;
3. a cleaning mechanism; 31. a connecting rod; 32. a scraper; 33. a limit stop; 34. balancing weight; 35. a movable outer tube; 36. a movable inner tube.
Detailed Description
The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
The recovery system of the present application comprises a pyrolysis system comprising a pyrolysis reactor body apparatus 2 and a heating apparatus 1. As shown in fig. 1 and 2, the pyrolysis reactor main body device comprises a pyrolysis reactor 2 and a rotating shaft 24 rotatably connected inside the pyrolysis reactor 2, wherein two ends of the rotating shaft 24 extend to the pyrolysis reactor 2, the rotating connection part of the pyrolysis reactor 2 and the rotating shaft 24 is sealed, and one end of the rotating shaft 24 is provided with a driving piece; the driving member may be a motor 22 separately provided to the pyrolysis reactor and fixed to one end of the rotation shaft 24 for driving the rotation shaft 24 to rotate.
The upper side of the outside of the pyrolysis reactor 2 is provided with a feed inlet 21, and the lower side of the outside of the pyrolysis reactor 2 is provided with a discharge outlet 23.
In one example of the pyrolysis system of the present application, the heating device 1 wraps around the outer wall of the pyrolysis reactor. In an embodiment in which the heating device is a flue gas heating device, the flue gas heating device is arranged around the outer wall of the pyrolysis reactor, a hollow channel is formed between the outer wall of the pyrolysis reactor and the inner wall of the flue gas heating device for circulating hot flue gas for indirect heating of the pyrolysis reactor. Preferably, the flow direction of the hot flue gas is opposite to the flow direction of the raw materials in the pyrolysis reactor so as to realize sufficient heat exchange.
Cleaning mechanism
As shown in fig. 4, the cleaning mechanisms 3 are equidistantly arranged on the rotating shaft 24 in the pyrolysis reactor 2; the cleaning mechanisms 3 are arranged in a plurality at equal intervals along the length direction of the rotating shaft 24, and are distributed at a certain included angle in the circumferential direction of the rotating shaft 24.
As shown in fig. 3, the cleaning mechanism 3 includes a link 31 fixedly connected to the rotation shaft 24. As shown in fig. 5, a movable inner tube 36 is vertically fixed at one end of the connecting rod 31 far away from the rotating shaft 24, two ends of the movable inner tube 36 are sleeved and rotatably connected with a movable outer tube 35, and a scraper 32 is fixed at the outer part of the movable outer tube 35; the scraper 32 can rotate at the end of the link 31 by the mechanism of the movable outer tube 35 and the movable inner tube 36.
The cleaning mechanism 3 of the present application can be in flexible contact with the inner wall of the pyrolysis reactor 2 to a certain extent when operating. Here, flexible contact refers to: when the rotating shaft 24 drives the cleaning mechanism 3 to rotate, the scraping plate on the cleaning mechanism 3 can realize continuous tangential contact along the inner wall of the pyrolysis reactor 2 so as to scrape off attachments attached to the inner wall of the pyrolysis reactor 2.
The materials in the pyrolysis reactor comprise pyrolysis products and waste lithium battery raw materials, so that the cleaning component disclosed by the application can fully turn over the raw materials to avoid the raw materials from accumulating and influencing the heat transfer efficiency besides the effect of scraping attachments on the inner wall of the pyrolysis reactor.
When the pyrolysis system is operated, waste lithium batteries are crushed and then enter the pyrolysis reactor 2 through the feed inlet 21; the heating device provides heat for indirectly heating the pyrolysis reactor 2; the motor 22 drives the rotation shaft 24 to rotate, and the cleaning mechanism 3 is driven to rotate by the rotation of the rotation shaft 24 through the connecting rod 31; along with the continuous change of the rotation angle of the cleaning mechanism 3, the scraping plate 32 rotates at the tail end of the connecting rod 31, and the arc-shaped tail end of the scraping plate 32 is in tangential contact with the inner wall of the pyrolysis reactor 2 to a certain extent, so that attachments attached to the inner wall of the pyrolysis reactor 2 are scraped off.
The term "to some extent" may be: the scraper 32 always maintains tangential contact with the inner wall of the pyrolysis reactor 2 within a rotation angle of more than 30 degrees of the rotating shaft 24; the rotation angle may also be 60 to 180 degrees, preferably 360 degrees.
As an example of the cleaning mechanism of the present application, as shown in fig. 3, a limit stop 33 with an arc structure is fixed at the upper end of the connecting rod 31 near the movable inner tube 36, for adjusting the inclination angle of the scraper 32; one end of the scraping plate 32 is fixed with a balancing weight 34, the other end of the scraping plate 32 is of an arc-shaped structural design, and the arc can be attached to the inner wall of the pyrolysis reactor 2. The scraper 32 has a width such that line contact, even surface contact, with the pyrolysis reactor can occur. The width of the scraping plate is not too large or too small, and because the width of the scraping plate is too large, the rotation resistance of the scraping plate can be increased, and the long-time smooth rotation of the scraping plate is not facilitated; the width of the scraping plate is too small, so that the contact area with the pyrolysis reactor becomes small, and the scraping efficiency is affected. In the present application, the width of the blade may be 2 to 15cm, preferably 8 to 15cm. In one example, the sum of the widths of the flights along the length of the pyrolysis reactor is 0.6 to 0.9 times, such as 0.8 times, the length of the pyrolysis reactor.
The weight 34 is used for adjusting the rotation angle of the squeegee 32 in the rotation direction of the rotation shaft 24, the limit stopper 33 is used for adjusting the rotation angle of the squeegee 32 in the rotation direction opposite to the rotation direction of the rotation shaft 24, and the limit stopper 33 has an arc θ. Under the cooperation of the balancing weight 34 and the limit stop 33, the rotating direction and the rotating reverse direction of the scraping plate 32 on the rotating shaft 24 are controlled, and the rotating angles of the two directions are controlled, so that the tangential contact degree of the cleaning mechanism and the pyrolysis reactor is controlled, and the cleaning degree of attachments on the inner wall of the pyrolysis reactor is controlled.
The volume of the balancing weight is not too large or too small. The volume of the balancing weight is too large, so that the space between the scraping plate and the connecting rod is occupied, and the rotation angle of the scraping plate is influenced; the volume of the balancing weight is too small, so that the rotation angle of the scraping plate is difficult to control in a proper range. In the present application, the height of the counterweight block above the squeegee panel can be 1-3cm, for example 2cm.
The broken material of the waste lithium battery mainly comprises a pole piece material and an electrolyte, and pyrolysis products generated after pyrolysis mainly comprise plastic diaphragm pyrolysis oil gas, the electrolyte and the like, so that the thickness of the scraping plate needs to be controlled within the range of 6-10 mm. If the thickness of the scraping plate is too large, the rotation resistance of the reactor is too large; if the thickness of the blade is too small, the scraping strength is affected.
As an example of the cleaning mechanism of the present application, the maximum rotation angle β between the squeegee and the bump stopper is 6 to 15 ° under the action of the weight block.
As an example of the cleaning mechanism of the present application, as shown in FIG. 7, the blade weight w 1 Weight of balancing weight w 2 The width m of the scraper blade, the distance L from the balancing weight to the rotation axis of the scraper blade, satisfies the following relationship: (w) 2 ×L+0.5w 1 ×0.5m)/(0.5w 1 ×0.5m)=2~3。
As an example of the cleaning mechanism according to the present application, as shown in fig. 6, two sets of cleaning mechanisms 3 are provided on the same circumferential section of the rotary shaft 24, and the two sets of cleaning mechanisms 3 form an angle of 180 degrees on the circumferential section.
According to the shape and size of the pyrolysis reactor, more groups of cleaning mechanisms can be arranged in the length direction of the rotating shaft; each group of cleaning mechanisms can be distributed on the rotating shaft at equal intervals; the included angle between the connecting rod and the rotating shaft in the cleaning mechanism can be the same or different, and the included angle is at least 30 degrees, for example, 60 degrees or 90 degrees.
Heating apparatus
The heating device 1 of the present application may be a flue gas heating device and an electromagnetic heating device.
In the embodiment of the flue gas heating device, the upper side and the lower side of the flue gas heating device are provided with communication ports, the two communication ports are distributed relatively, and the circulation direction of hot flue gas in the flue gas heating device is opposite to the circulation direction of raw materials in the pyrolysis reactor so as to realize full heat exchange. The flue gas outlet of the flue gas heating equipment is provided with a temperature sensor for monitoring the temperature of the flue gas outlet.
In an embodiment of the electromagnetic heating device, the electromagnetic heating device employs electromagnetic heating and/or heating wire heating means. The power of the electromagnetic heating device is 500-1000kw.
Multistage pyrolysis system
The pyrolysis system of the present application may comprise a two or more stage pyrolysis reactor body apparatus, a two or more stage flue gas heating apparatus, thereby forming a multi-stage pyrolysis system. The main body equipment of each stage of pyrolysis reactor is matched with 1 stage of flue gas heating equipment; or two or more pyrolysis reactor main body devices share stage 1 flue gas heating devices; wherein, the pyrolysis reactor discharge port of the main body equipment of the pyrolysis reactor of the previous stage is communicated with the pyrolysis reactor feed port of the main body equipment of the pyrolysis reactor of the next stage. Optionally, the pyrolysis systems of each stage can be independently connected in series or in parallel.
As an example of the multi-stage pyrolysis system of the present application, as shown in fig. 8, the pyrolysis system is a secondary pyrolysis system, wherein the primary pyrolysis system comprises a 1-1 pyrolysis system and a 1-2 pyrolysis system, and the secondary pyrolysis system comprises a 2-1 pyrolysis system; wherein, the 1-1 pyrolysis system and the 1-2 pyrolysis system are connected in parallel; the 1-1 pyrolysis system and the 1-2 pyrolysis system are respectively connected with the 2-1 stage pyrolysis system in parallel. The 1-1 pyrolysis system, the 1-2 pyrolysis system and the 2-1 stage pyrolysis system are respectively provided with 1 pyrolysis reactor main body equipment. The 2 pyrolysis reactor main body devices of the primary pyrolysis system are communicated at a feed inlet 21, and the discharge outlets of the 2 pyrolysis reactor main body devices are respectively communicated with the feed inlet of the pyrolysis reactor main body device of the secondary pyrolysis system; the pyrolysis reactor body equipment of the secondary pyrolysis system is connected to the feed inlet 21.
Pyrolysis process
The pyrolysis method of the waste lithium battery comprises the following steps:
carrying out charged crushing on the waste lithium batteries, and protecting inert gas in the crushing process;
the crushed raw materials are sent into a pyrolysis reactor 2, the pyrolysis reactor 2 is indirectly heated by flue gas through flue gas heating equipment, and pyrolysis reaction is carried out to obtain pyrolysis gas and pyrolysis solids;
the temperature of the pyrolysis reaction is 400-500 ℃, and the residence time of the raw materials in the pyrolysis reactor is 30-40min;
when the pyrolysis reactor is adopted to carry out pyrolysis on the waste lithium batteries, the yield of the black powder is higher than 98 weight percent, even higher than 99 weight percent, even higher than 99.5 weight percent after the obtained pyrolysis solid is subjected to grinding and selecting.
In one embodiment, the inert gas is nitrogen, and the size of the crushed waste lithium batteries is between 1 cm and 3cm.
In the embodiment of the flue gas heating device, the flue gas flow can be controlled between 3000 and 5000Nm 3 In the range of/h.
The attachments on the inner wall of the pyrolysis reactor can be as follows: cokes generated by pyrolysis reaction and waste lithium batteries which are not stirred in time and accumulated. These deposits, due to the coating on the inner wall of the pyrolysis reactor, affect the heat exchange efficiency of the hot flue gas and the pyrolysis reactor, resulting in various problems such as uneven pyrolysis, insufficient pyrolysis, unstable pyrolysis, and the like.
The flue gas heating device provides a temperature stable hot flue gas. And a temperature sensor is arranged at the smoke outlet and used for monitoring the temperature fluctuation condition of the smoke outlet in the operation process of the pyrolysis system, so that the accumulation condition of attachments on the inner wall of the pyrolysis reactor is judged. If the temperature fluctuation at the flue gas outlet is small (within 50 ℃) or no temperature fluctuation exists, the inner wall of the pyrolysis reactor can be judged to be basically free of deposit accumulation; if the temperature fluctuation at the smoke outlet is large (higher than 50 ℃), the deposition of attachments with a certain thickness on the inner wall of the pyrolysis reactor can be judged, at the moment, the operation of the pyrolysis system is required to be stopped, the attachments are cleaned, and the pyrolysis system can be restarted.
The recovery system of the application also comprises a screening system, wherein the screening system comprises a grinding device and a screening device, and the mesh size of the screening device is 100-150 meshes.
The pyrolysis system is adopted to carry out pyrolysis on the waste lithium batteries, and the temperature fluctuation at the smoke outlet can be controlled within 50 ℃, preferably within 25 ℃, even preferably within 20 ℃, such as within 12 ℃ and within 5 ℃.
The pyrolysis system provided by the application is used for pyrolyzing the waste lithium batteries, and can be operated continuously for more than 5 days, preferably more than 10 days, even preferably more than 28 days, so that the pyrolysis system is kept substantially free of deposit accumulation.
The pyrolysis system of the application is adopted to pyrolyze the waste lithium batteries, and the flue gas flow is controlled to be 3000-5000Nm 3 Preferably controlled at 3000-4000Nm 3 Preferably at 3500Nm 3 /h。
The pyrolysis system provided by the application is used for pyrolyzing the waste lithium batteries, and the treatment capacity can reach 1000 kg/hour to 1500 kg/hour.
The pyrolysis system is adopted to pyrolyze the waste lithium batteries, and the rotating speed of the rotating shaft can be 1-5r/min.
By adopting the pyrolysis system to pyrolyze the waste lithium batteries, the filling degree of the volume of the materials in the pyrolysis reactor can reach 20-60% by volume, and the inner wall of the pyrolysis reactor is kept basically free of attachments.
The pyrolysis system of the application is adopted to carry out pyrolysis on the waste lithium batteries, and the flue gas temperature is controlled at 600-700 ℃.
The pyrolysis system provided by the application is adopted to carry out pyrolysis on the waste lithium batteries, and the yield of the black powder is higher than 97% by weight after the obtained pyrolysis solid is ground and selected.
By adopting the pyrolysis system to pyrolyze the waste lithium batteries, the diaphragms and the electrolyte in the waste lithium batteries can be fully pyrolyzed and volatilized, and the pyrolysis solid products are more beneficial to subsequent separation due to the removal of the diaphragms and the electrolyte, so that the high-purity products can be separated only by simple grinding and selecting. In one embodiment, the pyrolysis solid product is milled for 10-15min and sieved through 100 mesh sieve to obtain high purity black powder.
The pyrolysis system is adopted to carry out pyrolysis on the waste lithium batteries, and the inner wall of the pyrolysis reactor is cylindrical; the pyrolysis reactor may have an inner diameter size of 1.2m to 1.5m.
In addition, the pyrolysis system of the present application is continuously operated, i.e., spent lithium batteries continue to enter the pyrolysis reactor. The pyrolysis efficiency of the pyrolysis system can reach more than 800kg/h, can reach more than 1000kg/h and even can reach 1500kg/h.
The effects of the present application are explained below by examples and comparative examples.
In the following examples and comparative examples, the waste lithium battery was an aluminum-shell square CATL ternary lithium battery cell, the surface was a blue plastic film package, the laser printing specification of the battery cell was 3.66V×154Wh, the battery size was 148mm×27mm×92mm, and the weight was 820-930g. The waste lithium battery is crushed in an electrified way by utilizing an SPD06180-01 type crusher, nitrogen protection is carried out in the crushing process, the size of the crushed waste lithium battery is 2-3cm, the crushed waste lithium battery comprises positive and negative electrode materials and vaporizable electrolyte, black powder of battery monomers is manually screened by a 100-mesh round screen, and the black powder rate is 66.50 wt% after detection.
Example 1:
and adopting a primary pyrolysis system to carry out pyrolysis process.
Sending the crushed waste lithium batteries into a horizontal cylindrical pyrolysis reactor by a closed spiral feeder, wherein the pyrolysis reactor is 6m long and 1.2m in diameter; 60 groups of cleaning mechanisms are arranged on a rotating shaft of the pyrolysis reactor, each group of cleaning mechanisms is positioned in the same circumferential section, each group of cleaning mechanism comprises 2 connecting rods and 2 scraping plates, and the 2 connecting rods are 180 degrees; the included angle between the connecting rod and the rotating shaft in each cleaning mechanism is 60 degrees;
weight of scraperw 1 =7612 g, weight w of balancing weight 2 3806g, width of the scraper m=8cm, distance from the counterweight to the rotation axis of the scraper l=8cm, (satisfying the following relationship (w) 2 ×L+0.5w 1 ×0.5m)/(0.5w 1 ×0.5m)=2~3)
The pyrolysis reactor is indirectly heated in a flue gas heating mode. The temperature of the flue gas inlet is controlled at 600 ℃, the flue gas outlet is provided with a temperature sensor for detecting the temperature of the flue gas outlet, and the temperature of the flue gas outlet is about 300 ℃; the pyrolysis temperature is 400 ℃, and the residence time of the waste lithium batteries in the pyrolysis reactor is 30min.
According to the treatment capacity of 1000 kg/hour, the crushed waste lithium batteries are conveyed to a pyrolysis reactor for continuous pyrolysis, the rotating speed of a rotating shaft is 5r/min, and pyrolysis gas discharged from a pyrolysis gas outlet of the pyrolysis reactor comprises plastic pyrolysis oil, gas and electrolyte and enters an incinerator for high-temperature incineration treatment.
And (3) cooling, conveying and discharging pyrolysis solids discharged from a pyrolysis solids outlet of the pyrolysis reactor, and conveying the pyrolysis solids to a pulverizer (brand: forward and remote, model LHQ-150, a linear screen and a 100-mesh screen) for grinding and selecting to obtain black powder and positive and negative metal materials. The black powder is mainly graphite and lithium carbonate materials, and the positive and negative metal materials are mainly copper sheets and aluminum foil materials.
The flue gas outlet temperature fluctuation conditions for the pyrolysis reactor operated for 80 days are shown in table 1 below.
TABLE 1
From the temperature monitoring of the flue gas outlet, it can be seen that the pyrolysis system is very stable in operation for 1-10 days, the temperature of the flue gas outlet is always kept at 250 ℃, the temperature of the flue gas outlet is increased to be up to 300 ℃ on the 20 th day of operation, and the temperature of the flue gas outlet is increased to 255 ℃.
The pyrolysis system is stopped, the pyrolysis reactor is checked, and the inner wall of the pyrolysis reactor is found to be accumulated with attachments, mainly cokes, and the average coking thickness is 0.5cm. Analysis shows that the generation of the cokes affects the heat transfer of the flue gas temperature to the pyrolysis materials, so that more heat cannot be transferred to the pyrolysis materials, and therefore, the temperature of the flue gas outlet is increased, and the thermal efficiency of the pyrolysis reaction is affected. During operation, the pyrolysis solid product is collected.
The pyrolysis solid product is subjected to the following grinding and sieving procedures
Adopting a spiral cooler to cool pyrolysis solids in two stages, cooling to 40 ℃, and then sending the pyrolysis solids into a pulverizer to pulverize for 10min, wherein the particle size of the obtained powder is smaller than 2mm; and then screening by adopting a linear screen, wherein the undersize is mainly black powder, and the oversize is mainly copper and aluminum. The yield and impurity content of the obtained black powder are shown in Table 2.
The spiral cooler is a two-stage spiral cooler which is connected in series and indirectly cooled by circulating cooling water, the spiral length is 6000mm, the diameter is 478mm, the pitch is 350mm, and the spiral rotating speed is 10r/min-15r/min.
The specification of the linear sieve is as follows: screen surface size: 500 x 2500mm, mesh size 100 mesh, vibration times: 960 times/min.
As can be seen from Table 2, after 60 days of operation, the soot yield tended to decrease significantly because the inner wall of the pyrolysis reactor gradually adhered to the coke with the increase of the operation time, resulting in a decrease in heat transfer efficiency, resulting in insufficient pyrolysis reaction, and the produced pyrolysis solids contained a certain amount of coke. When the black powder in the pyrolysis solid is subjected to primary screening, a small amount of black powder is attached to the oversize product (mainly copper sheet and aluminum foil), so that the black powder content in the undersize product of the primary screening is reduced.
TABLE 2
Comparative example
According to the same conditions as in example 1, a rotary kiln (length 6m, cylinder diameter 1.2m, no cleaning mechanism) was used to pyrolyze the waste lithium batteries, and the flue gas outlet temperature was monitored. The fluctuation of the flue gas outlet temperature is shown in table 3 below.
TABLE 3 Table 3
The rotary kiln was operated on day 3 and the flue gas outlet temperature was found to be an indication of an increase to 285 on day 10 and 300 ℃ on day 20.
And stopping the furnace on the 20 th day of the operation of the rotary kiln, and checking to find that a large amount of cokes adhere to the inner wall of the rotary kiln, wherein the average coking thickness is 3cm. According to the fluctuation condition of the flue gas outlet temperature, analysis shows that the rotary kiln has coked material on the 3 rd day of operation, and along with continuous accumulation of the coked material, the heat transfer efficiency of the flue gas and pyrolysis materials is gradually reduced, so that coking is more serious.
In this comparative example, the pyrolysis solids were subjected to the pulverizing and sieving process in the same manner as in example 1, and the black powder yield and the impurity content thereof are shown in the following table 4:
TABLE 4 Table 4
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the application.

Claims (10)

1. A recovery system for separating black powder from waste lithium batteries is characterized in that: the recovery system comprises a pyrolysis system and a screening system, wherein the pyrolysis system comprises pyrolysis reactor main body equipment and heating equipment;
the main pyrolysis reactor equipment comprises a pyrolysis reactor (2) and a rotating shaft (24) rotatably connected inside the pyrolysis reactor (2), wherein two ends of the rotating shaft (24) extend to the pyrolysis reactor (2), the rotating joint of the pyrolysis reactor (2) and the rotating shaft (24) is sealed, and one end of the rotating shaft (24) is provided with a driving piece;
cleaning mechanisms (3) are arranged on the rotating shaft (24) at equal intervals, and the cleaning mechanisms (3) can be in flexible contact with the inner wall of the pyrolysis reactor (2);
a feed inlet (21) is formed in the upper side of the outer part of the pyrolysis reactor (2), and a discharge outlet (23) is formed in the lower side of the outer part of the pyrolysis reactor (2);
heating equipment is arranged at the periphery of the pyrolysis reactor and is used for indirectly heating the pyrolysis reactor,
the screening system comprises a grinding device and a screening device, wherein the grinding device and the screening device are used for grinding and screening pyrolysis solids, and the mesh size of the screening device is 100-150 meshes.
2. The recovery system of claim 1, wherein: the cleaning mechanisms (3) are equidistantly arranged along the length direction of the rotating shaft (24) and distributed in a staggered manner in the circumferential direction of the rotating shaft (24).
3. The recovery system of claim 1, wherein: the cleaning mechanism (3) comprises a connecting rod (31) fixedly connected with the rotating shaft (24), one end of the connecting rod (31) far away from the rotating shaft (24) is vertically fixed with a movable inner tube (36), two ends of the movable inner tube (36) are sleeved and connected with a movable outer tube (35) in a rotating way, a scraping plate (32) is fixed on the outer part of the movable outer tube (35),
one end of the scraping plate (32) is fixed with a balancing weight (34), the other end of the scraping plate (32) is of an arc-shaped structural design, and the arc can be attached to the inner wall of the pyrolysis reactor (2);
and a limit stop block (33) with an arc structure is fixed at the upper end of the connecting rod (31) close to the movable inner pipe (36) and is used for adjusting the inclination angle of the scraping plate (32).
4. A recycling system according to claim 1, characterized in that: the heating equipment is flue gas heating equipment, the flue gas heating equipment comprises a flue gas heating box (1), communication openings are formed in the upper side and the lower side of the flue gas heating box (1), and the two communication openings are distributed relatively.
5. The recovery system of claim 2, wherein: two or more groups of cleaning mechanisms (3) are arranged on the rotating shaft (24), the included angles of two adjacent groups of cleaning mechanisms (3) in the circumferential direction of the rotating shaft (24) are the same, and the included angles are 30-180 degrees.
6. The recovery system of any one of claims 1-5, wherein: the pyrolysis system comprises a two-stage or more-stage pyrolysis reactor main body device and a two-stage or more-stage flue gas heating device,
the main body equipment of each stage of pyrolysis reactor is matched with primary flue gas heating equipment; or two or more pyrolysis reactor main body devices share one flue gas heating device;
wherein, the pyrolysis reactor discharge port (23) of the main body equipment of the pyrolysis reactor at the upper stage is communicated with the pyrolysis reactor feed port (21) of the main body equipment of the pyrolysis reactor at the lower stage.
7. The recovery method for separating the black powder from the waste lithium battery is characterized by comprising the following steps of:
carrying out charged crushing on the waste lithium batteries, and protecting inert gas in the crushing process;
the crushed raw materials are sent into a pyrolysis reactor (2), and the pyrolysis reactor (2) is indirectly heated by adopting flue gas through flue gas heating equipment to carry out pyrolysis reaction to obtain pyrolysis gas and pyrolysis solids;
the temperature of the pyrolysis reaction is 350-450 ℃, and the residence time of the raw materials in the pyrolysis reactor is 20-60min;
and grinding and sieving the pyrolysis solid to obtain black powder, wherein the grinding time is 10-15min, and the sieving is 100-150 mesh sieving.
8. The method according to claim 7, wherein the inert gas is nitrogen, and the size of the crushed waste lithium batteries is between 1 cm and 3cm.
9. The recovery method according to claim 7, wherein the flow rate of the flue gas heating apparatus is controlled to 3000-5000Nm 3 In the range of/h.
10. The recycling method according to claim 7, characterized in that the heating device is an electromagnetic heating device, wherein the power of the electromagnetic heating device is 500-1000kw.
CN202311422055.7A 2023-10-31 2023-10-31 Recovery system and method for separating black powder from waste lithium batteries Active CN117154277B (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113161640A (en) * 2021-02-03 2021-07-23 顺尔茨环保(北京)有限公司 System and method for recycling black powder through multistage pyrolysis of waste lithium batteries
KR102334865B1 (en) * 2021-07-16 2021-12-03 에스아이에스 주식회사 Batch processing system for waste lithium secondary battery
CN115663328A (en) * 2022-11-15 2023-01-31 中山大学 Separation device for waste lithium battery electrode surface coating
WO2023070801A1 (en) * 2021-10-31 2023-05-04 湖南江冶机电科技股份有限公司 Recovery method for valuable components of waste lithium-ion batteries
CN116646632A (en) * 2023-05-15 2023-08-25 山东恒泰利华环境科技有限公司 Continuous waste lithium battery black powder recycling device and method

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113161640A (en) * 2021-02-03 2021-07-23 顺尔茨环保(北京)有限公司 System and method for recycling black powder through multistage pyrolysis of waste lithium batteries
KR102334865B1 (en) * 2021-07-16 2021-12-03 에스아이에스 주식회사 Batch processing system for waste lithium secondary battery
WO2023070801A1 (en) * 2021-10-31 2023-05-04 湖南江冶机电科技股份有限公司 Recovery method for valuable components of waste lithium-ion batteries
CN115663328A (en) * 2022-11-15 2023-01-31 中山大学 Separation device for waste lithium battery electrode surface coating
CN116646632A (en) * 2023-05-15 2023-08-25 山东恒泰利华环境科技有限公司 Continuous waste lithium battery black powder recycling device and method

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