Treatment system of waste lithium ion battery

Abstract

The utility model provides a waste lithium ion battery treatment system. The waste lithium ion battery processing system comprises: a thermal decomposition system for roasting a waste lithium ion battery at a first temperature to generate a roasted product; a first dissolving tank in which the roasted product is immersed in water; a first separator for performing first solid-liquid separation on the immersed aqueous solution in the first dissolving tank; a first devitrifier that performs a first devitrification in which lithium carbonate is precipitated from the aqueous solution separated by the first solid-liquid separation; a second separator for recovering lithium carbonate by performing second solid-liquid separation on a slurry containing lithium carbonate precipitated by the first crystallization; and a grinder that grinds the roasted product so that the roasted product has a predetermined average particle diameter or less before the roasted product is introduced into the first dissolution tank.

Description

Technical Field

[0001] The present disclosure relates to a system for processing spent lithium-ion batteries. Background Art

[0002] A treatment system for recovering lithium as a rare metal from discarded lithium ion batteries is known. For example, in the following patent document 1, a waste lithium ion battery is roasted and the roasted waste lithium ion battery is introduced into a dissolution tank storing water. Thus, an aqueous solution in which lithium is dissolved is generated, and lithium carbonate is precipitated from the aqueous solution by crystallization.

[0003] Patent Document 1: International Publication No. 2020 / 246079

[0004] However, waste lithium-ion batteries may be partially lumped due to roasting. If the calcined waste lithium-ion batteries in such a state are directly introduced into a dissolving tank, the lithium in the calcined bulk will be difficult to dissolve in water, and the recovery rate of lithium may be reduced. In addition, the calcined bulk may also clog the piping of the dissolving equipment. Utility Model Content

[0005] The present disclosure aims to provide a waste lithium ion battery processing system capable of appropriately dissolving the calcined waste lithium ion batteries.

[0006] A waste lithium ion battery processing system according to one embodiment of the present disclosure is a waste lithium ion battery processing system for recovering lithium from waste lithium ion batteries, wherein the waste lithium ion battery processing system comprises: a thermal decomposition system, which roasts the waste lithium ion batteries at a first temperature to generate a roasted product; a first dissolution tank, which immerses the roasted product in water; a first separator, which performs a first solid-liquid separation on the aqueous solution after immersion in the first dissolution tank; a first crystallizer, which performs a first crystallization to precipitate lithium carbonate from the aqueous solution separated by the first solid-liquid separation; a second separator, which performs a second solid-liquid separation on a slurry containing lithium carbonate precipitated by the first crystallization and recovers lithium carbonate; and a grinder, which grinds the roasted product in a manner such that the roasted product has an average particle size less than a predetermined average particle size before introducing the roasted product into the first dissolution tank.

[0007] In the above-mentioned embodiment, the thermal decomposition system includes a heater, which heats the waste lithium-ion battery to the first temperature, and the grinder includes: a crusher having rotating teeth, which crushes the introduced roasted material by rotating the rotating teeth; a classifier, which classifies the roasted material crushed by the crusher; and a controller, which controls the rotation speed of the rotating teeth, the heater is configured to change the first temperature by changing the target temperature, and the controller controls the rotation speed of the rotating teeth according to the target temperature of the heater.

[0008] In the above-mentioned embodiment, the treatment system of the waste lithium-ion battery comprises: a second dissolution tank, which immerses the solid component containing lithium carbonate separated by the second solid-liquid separation in water; a third separator, which performs a third solid-liquid separation using an ultrafiltration membrane on the aqueous solution after immersion in the second dissolution tank; a second crystallizer, which performs a second crystallization to precipitate lithium carbonate from the aqueous solution separated by the third solid-liquid separation; and a fourth separator, which performs a fourth solid-liquid separation on the slurry containing lithium carbonate precipitated by the second crystallization and recovers the lithium carbonate.

[0009] In the above aspect, the third separator includes a coarse filter and an ultrafilter for ultrafiltering the aqueous solution after passing through the coarse filter.

[0010] In the above-mentioned method, the thermal decomposition system includes: a preheater, which heats the waste lithium ion battery at a second temperature lower than the first temperature in order to decompose and remove the electrolyte contained in the waste lithium ion battery before roasting the waste lithium ion battery; a crusher, which crushes the waste lithium ion battery after being heated at the second temperature; and a sorter, which separates the positive electrode active material from the positive electrode current collector of the crushed waste lithium ion battery and sorts the positive electrode active material.

[0011] According to the present disclosure, it is possible to perform appropriate dissolution treatment on spent lithium-ion batteries after calcination. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic process diagram showing a treatment process of a waste lithium-ion battery treatment system according to an embodiment of the present disclosure.

[0013] Figure 2 It is shown that the Figure 1 A schematic diagram of the system configuration of the thermal decomposition step and the grinding step is shown.

[0014] Figure 3 It is a schematic structural diagram showing the grinding machine of this embodiment.

[0015] Figure 4 Yes Figure 1 A schematic diagram of the recovery system of the recovery process shown.

[0016] Figure 5 It is a schematic diagram showing a system configuration for implementing a thermal decomposition step and a polishing step according to a modification of the present disclosure.

[0017] Description of symbols

[0018] 1: thermal decomposition system; 11: pre-treatment device (preheater); 12a: crusher; 12b: sorter; 13b: heater; 20: grinder; 20a: pulverizer; 20b: classifier; 20d: rotating teeth; 20m: second controller (controller of grinder); 21: first dissolution tank; 22: first separator; 23: first crystallizer; 24: second separator; 25: second dissolution tank; 26: third separator; 27: second crystallizer; 28: fourth separator. DETAILED DESCRIPTION

[0019] Hereinafter, one embodiment of the present disclosure will be described with reference to the drawings. Figure 1 This is a schematic process diagram showing a treatment process of a waste lithium-ion battery treatment system according to an embodiment of the present disclosure.

[0020] The waste lithium-ion battery to be treated by the treatment system of this embodiment includes, for example, lithium compounds such as lithium iron phosphate or ternary lithium containing nickel, cobalt, and manganese as positive electrode active materials, graphite as negative electrode active materials, and aluminum foil or copper foil as current collectors. The waste lithium-ion battery is filled with electrolyte. Hereinafter, the waste lithium-ion battery is sometimes referred to as waste LIB.

[0021] This processing system targets large waste LIBs, that is, battery modules composed of battery cells of multiple waste LIBs, and battery packs composed of multiple battery modules. The battery pack is configured to accommodate multiple electrically connected battery modules, a control device, and a cooling device in a housing. This processing system, for example, assumes that waste LIBs mounted on electric vehicles or hybrid vehicles are removed and processed without disassembling the removed waste LIBs, that is, battery packs or battery modules.

[0022] like Figure 1 As shown, the treatment system of this embodiment includes in the treatment process: a thermal decomposition process P1, thermally decomposing the waste LIB and roasting the obtained powder containing the active material; a grinding process P20, grinding the roasted active material; and a recovery process P2, recovering lithium after immersing the ground active material in water to dissolve the lithium.

[0023] First, the thermal decomposition step P1 is described. The thermal decomposition step P1 includes a pretreatment step P11, a crushing and sorting step P12, and a calcining step P13. Figure 2 It is shown that the Figure 1 The schematic diagram of the system configuration of the thermal decomposition step and the grinding step is shown. The thermal decomposition system 1 for performing the thermal decomposition step P1 includes a supply device 10, a pre-treatment device 11, a crushing and sorting device 12, and a rotary kiln 13 configured as a roasting device.

[0024] In the pretreatment step P11, in order to decompose and remove the electrolyte contained in the waste LIB, the waste LIB is heated at a second temperature lower than the first temperature, that is, pre-baked. The first temperature is the baking temperature in the baking step P13 described later. Therefore, the waste LIB is supplied from the supply device 10 to the pretreatment device 11. The supply device 10 is composed of, for example, a belt conveyor. The pretreatment device 11 includes a preheater that heats the waste LIB at the second temperature. The pretreatment device 11 is composed of, for example, a grate preheater that heats the waste LIB while conveying it.

[0025] The second temperature in the pretreatment step P11 is set to a temperature at which the electrolyte contained in the waste LIB can be decomposed and removed. For example, the second temperature is 150°C or higher and lower than 400°C, or may be 150°C or higher and 250°C or lower.

[0026] In the crushing and sorting step P12, the waste LIB treated in the pre-treatment step P11 is crushed to separate the active material from the current collector of the crushed waste LIB to sort the active material. For this purpose, the crushing and sorting device 12 includes a crusher 12a and a sorter 12b. The crusher 12a is composed of, for example, a roller crusher. The crusher 12a crushes large waste LIBs, that is, battery packs or battery modules, into a size of a battery cell or smaller than a battery cell.

[0027] The sorting machine 12b is configured to separate the active material from the current collector for the waste LIB crushed by the crusher 12a, and to sort and take out the active material. The sorting machine 12b is configured, for example, by a sieve vibrator or the like. In fact, not only the positive electrode active material but also a small amount of impurities other than the active material such as the negative electrode active material are taken out by the sorting machine 12b and supplied to the rotary kiln 13. The outer packaging materials, current collectors, etc. of the waste LIBs other than these are transported to other processing equipment.

[0028] In the roasting step P13, the active material of the waste LIB sorted by the crushing and sorting step P12, that is, the positive electrode active material, is roasted at a predetermined first temperature. The rotary kiln 13 as a roasting device is composed of, for example, an externally heated rotary kiln. The rotary kiln 13 includes: a cylinder 13a with a circular cross-section, which is supported so as to be able to rotate around the central axis C1; and a heater 13b, which heats the outer wall of the cylinder 13a. The heater 13b may also include a plurality of heaters divided along the direction of the central axis C1 of the cylinder 13a. In this case, the target temperatures of the plurality of heaters may also be set separately.

[0029] The cylinder 13a has one end as a receiving port 13c and the other end as a discharge port 13d, and is supported to be rotatable about the central axis C1 in a state where the central axis C1 is inclined downward at a predetermined angle from the receiving port 13c toward the discharge port 13d. The waste LIB supplied from the crushing and sorting device 12 to the receiving port 13c of the cylinder 13a is transported toward the discharge port 13d by the rotation of the cylinder 13a.

[0030] The interior of the cylinder 13a is an air atmosphere. Alternatively, the interior of the cylinder 13a may be a reducing atmosphere or a low-oxygen atmosphere, for example, with an oxygen concentration of less than 10%. The heater 13b is, for example, composed of a heating jacket surrounding the outer periphery of the cylinder 13a. By supplying heating gas to the heater jacket, the outer wall of the cylinder 13a is heated. As a result, the waste LIB transported inside the cylinder 13a is heated, becomes a roasted product, and is discharged from the discharge port 13d. The first temperature, which is the roasting temperature in the roasting step P13, is 400°C or higher, for example, 800°C.

[0031] Thus, the rotary kiln 13 rotates the waste LIB introduced from one end of the drum 13a around the central axis C1 in the drum 13a, thereby calcining the waste LIB while conveying it to the other end of the drum 13a at a conveying speed corresponding to the rotation speed of the drum 13a.

[0032] Thus, in the thermal decomposition step P1 of the present embodiment, after the electrolyte contained in the waste LIB is rendered harmless by the preheater, the waste LIB is crushed and sorted. As a pretreatment step P11 before the crushing and sorting step P12, heating by the preheater is performed, thereby decomposing and removing the electrolyte to ensure safety in the crushing step. In addition, by calcining the waste LIB after the crushing and sorting step P12, it is not necessary to heat the unnecessary parts such as the shell and current collector contained in the waste LIB, and heat consumption can be suppressed.

[0033] In the grinding step P20, the active material calcined in the thermal decomposition step P1, that is, the calcined product, is ground. The processing system has a grinder 20 for performing the grinding step P20. The calcined product discharged from the discharge port 13d of the rotary kiln 13 is introduced into the grinder 20. The grinder 20 grinds the introduced calcined product so that the introduced calcined product becomes less than a predetermined average particle size.

[0034] Figure 3 2 is a schematic structural diagram showing a grinding machine according to the present embodiment. Figure 3 As shown, the grinding machine 20 includes a pulverizer 20a and a classifier 20b. For example, in the grinding machine 20, the pulverizer 20a and the classifier 20b are provided in one housing 20c.

[0035] The pulverizer 20a is arranged at the bottom of the housing 20c, and the calcined product introduced is pulverized by the rotating teeth 20d rotating around the vertical axis C2. In addition, the calcined product introduced into the pulverizer 20a is ground between the stator 20e and the rotating teeth 20d fixed around the rotating teeth 20d. The teeth for grinding can also be formed on the stator 20e. The classifier 20b has a partition 20f rotating around the vertical axis C2. The bottom surface of the partition 20f is circular. The partition 20f has a plurality of plates 20g on the side. The partition 20f rotates together with the rotating teeth 20d. Air is introduced into the pulverizer 20a from the outside, and the calcined product that is ground and the particle size becomes smaller is blown upward between the plates 20g of the partition 20f. At this time, the centrifugal force acting on the calcined product after being crushed and ground by the swirling flow of the partition 20f produces a difference due to the particle size of the calcined product. Therefore, the calcined material with a larger particle size is introduced into the pulverizer 20a again and pulverized again by the rotating teeth 20d. In this way, in the classifier 20b, the pulverized material is air-transported by the centrifugal force corresponding to the rotation speed of the partition plate 20f, and the calcined material with a predetermined average particle size or less is air-transported and discharged from the discharge port 20h located at the upper part of the housing 20c.

[0036] exist Figure 3 In the example of FIG. 1 , the pulverizer 20a and the classifier 20b are connected integrally, and the rotating teeth 20d of the pulverizer 20a and the partition plate 20f of the classifier 20B rotate around the vertical axis C2 at the same rotation speed. In addition, the pulverizer 20a and the classifier 20b may be separately configured. That is, the rotating part 20d and the partition plate 20f may rotate at different rotation speeds.

[0037] For example, the average particle size of the calcined material conveyed by the air flow in the classifier 20b is set to a value smaller than the average particle size of the calcined material discharged from the rotary kiln 13. For example, the average particle size of the calcined material discharged from the rotary kiln 13 is about 1 mm. In this case, the average particle size of the calcined material conveyed by the air flow in the classifier 20b is set to 20 μm, for example. In addition, the greater the rotation speed of the cylinder 13a, the smaller the average particle size of the calcined material discharged from the rotary kiln 13, and the smaller the rotation speed of the cylinder 13a, the larger the average particle size of the calcined material discharged from the rotary kiln 13.

[0038] In addition, the grinder 20 can include a grading cyclone separator 20j and a dust collector 20k connected to the downstream of the discharge port 20i of the housing 20c. The grading cyclone separator 20j and the dust collector 20k separate the roasted product conveyed by the airflow from the air. First, the roasted product discharged from the housing 20c is introduced into the grading cyclone separator 20j through the discharge pipe 20i connected to the discharge port 20h. The grading cyclone separator 20j captures the roasted product. The captured roasted product is discharged from the bottom of the grading cyclone separator 20j. The remaining processed product is sent to the dust collector 20k. The roasted product with a smaller particle size contained in the processed product is discharged from the bottom of the dust collector 20k as dust. The air from which the roasted product has been removed is discharged from the side of the dust collector 20k. The discharged air can also be introduced into the housing 20c again. The roasted product discharged from the grading cyclone separator 20j and the dust collector 20k is sent to the recovery process P2 as the next process through the conveyor 201 and the like. In this way, the average particle size of the calcined product sent to the recovery step P2 is equal to or smaller than the average particle size predetermined in the classifier 20b.

[0039] Next, the recovery step P2 will be described. The recovery step P2 includes a first dissolution step P21, a first separation step P22, a first crystallization step P23, and a second separation step P24. Figure 4 Yes Figure 1 The recovery system 2 includes a first dissolution tank 21 , a first separator 22 , a first crystallizer 23 , and a second separator 24 .

[0040] In the first dissolving step P21, the calcined product ground in the grinding step P20 is immersed in water. For this purpose, the first dissolving tank 21 is configured to store water and to introduce the calcined product discharged from the grinder 20. The calcined product is supplied to the first dissolving tank 21 via the hopper 29 in a predetermined amount each time. Thus, the aqueous solution in the first dissolving tank 21 becomes a mixture of water and the calcined product. The first dissolving tank 21 has a stirring mechanism for stirring the aqueous solution in the tank.

[0041] In addition, in the first dissolution step P21, carbon dioxide gas is introduced into the first dissolution tank 21. The calcined product supplied to the first dissolution tank 21 is immersed in water while being bubbled with carbon dioxide gas. The pH of the aqueous solution is adjusted to a weak alkaline state by bubbling with carbon dioxide gas. Thus, the following reaction is promoted, and the poorly soluble lithium carbonate becomes easily soluble lithium bicarbonate and is dissolved in the aqueous solution in the first dissolution tank 21.

[0042] Li2CO3+CO2+H2O→2LiHCO3

[0043] In addition, the easily soluble lithium oxide also becomes poorly soluble lithium carbonate as shown in the following reaction formula, but further reacts with carbon dioxide gas to become easily soluble lithium bicarbonate and dissolve as described above.

[0044] Li2O+CO2→Li2CO3

[0045] In addition, by bubbling carbon dioxide gas, the pH of the aqueous solution can be maintained at a neutral or near-neutral value, for example, 5.5 to 8.5. If lithium oxide or the like is dissolved without bubbling carbon dioxide gas, the aqueous solution becomes alkaline, in which case aluminum is easily dissolved. By bubbling carbon dioxide gas as in the present embodiment and maintaining the pH at a neutral or near-neutral value, the dissolution of aluminum can be suppressed, and the solid components containing aluminum can be removed in the next first separation step P22.

[0046] In the first separation step P22, the aqueous solution treated in the first dissolution step P21 is subjected to the first solid-liquid separation. Therefore, the first separator 22 is composed of a solid-liquid separation device including a coarse filter such as a basket coarse filter, a precision filter, etc. The aqueous solution after immersion in the first dissolution tank 21 is introduced into the first separator 22. The aqueous solution is subjected to solid-liquid separation by the first separator 22, thereby removing solid components such as nickel, cobalt, manganese, aluminum, and graphite from the aqueous solution.

[0047] In the first crystallization step P23, the first crystallization is performed to precipitate lithium carbonate from the aqueous solution from which the solid components are removed in the first separation step P22. The first crystallizer 23 heats the aqueous solution to a temperature of 80° C. or higher using, for example, a heater. As the first crystallizer 23, for example, an MVR (Mechanical Vapor Recompression) type evaporation concentration device is used. The temperature of the heated aqueous solution is, for example, 85° C. By heating the aqueous solution, lithium bicarbonate is precipitated as lithium carbonate as shown in the following reaction formula.

[0048] 2LiHCO3→Li2CO3+CO2+H2O

[0049] The first crystallizer 23 generates a slurry containing lithium carbonate. In addition, the carbon dioxide gas generated by the above reaction may be used as the carbon dioxide gas introduced into the first dissolution tank 21 .

[0050] In the second separation step P24, the slurry containing the lithium carbonate precipitated in the first crystallization step P23 is subjected to the second solid-liquid separation. Therefore, the second separator 24 is composed of a solid-liquid separation device including a filter press, etc. The slurry is subjected to solid-liquid separation by the second separator 24, thereby taking out the solid component containing lithium carbonate from the slurry as a recyclate. The remaining filtrate can be discarded or returned to the first dissolving tank 21 again. In addition, the remaining filtrate can also be introduced into the second dissolving tank 25 described later. In addition, when the filtrate is introduced into the first dissolving tank 21 or the second dissolving tank 25, the filtrate can also be introduced into the first dissolving tank 21 or the second dissolving tank 25 after being cooled to room temperature by a heat exchanger. In addition, the second separator 24 can also be composed of the same solid-liquid separation device as the first separator 22.

[0051] In addition, in the present embodiment, the solid component containing lithium carbonate separated by the second solid-liquid separation is immersed in water again. Therefore, the recovery step P2 further includes a second dissolution step P25, a third separation step P26, a second crystallization step P27, and a fourth separation step P28.

[0052] In the second dissolution step P25, the solid component containing lithium carbonate separated in the second separation step P24 is immersed in water. For this reason, the second dissolution tank 25 is configured to store water and to introduce the solid component containing lithium carbonate discharged from the second separator 24. The second dissolution tank 25 also has a stirring mechanism for stirring the aqueous solution in the tank, similar to the first dissolution tank 21. The water stored in the second dissolution tank 25 may also contain the filtrate discharged in the second separation step P24.

[0053] In the second dissolution process P25, when the solid component containing lithium carbonate is mixed with water and stirred in the second dissolution tank 25, bubbling of carbon dioxide gas is not performed. In the first dissolution process P21, by bubbling of carbon dioxide gas, there is a situation where a certain amount of nickel and the like become carbonates and dissolve in the aqueous solution. Such carbonates of nickel and the like will not be recovered as residues in the first separation process P22. As a result, carbonates are precipitated in the first crystallization process P23. Therefore, the solid component containing lithium carbonate separated in the second separation process P24 may contain trace amounts of impurities such as nickel. For example, the purity of lithium carbonate in the solid component containing lithium carbonate separated in the second separation process P24 is about 98% to 99%.

[0054] When such solid components containing lithium carbonate are immersed in water in the second dissolution process P25, carbon dioxide gas is not bubbled, so that the aqueous solution becomes alkaline. Therefore, impurities such as trace nickel contained as carbonate can be insoluble in water. In this way, by making the pH of the aqueous solution in the two dissolution processes P21 and P25 different, impurities such as solid components containing aluminum and nickel can be removed in stages in subsequent separation processes P22 and P26. Thus, the purity of the lithium carbonate finally recovered can be further improved. For example, the purity of the lithium carbonate in the solid components containing lithium carbonate separated in the 4th separation process P28 described later is about 99.5%.

[0055] In the third separation process P26, the aqueous solution treated by the second dissolution process P25 is subjected to solid-liquid separation. In the present embodiment, the third separator 26 includes an ultrafilter for performing the third solid-liquid separation using an ultrafiltration membrane on the aqueous solution after immersion in the second dissolution tank 25. The pore size of the ultrafiltration membrane in the ultrafilter is smaller than the pore size in the first separator 22 used in the first separation process P22 and the second separator 24 used in the second separation process P24. For example, the pore size of the ultrafiltration membrane is less than 1 μm, for example, 0.03 μm. The solid component containing lithium carbonate introduced into the second dissolution process P25 contains trace impurities including nickel, cobalt, manganese, etc. Thus, these impurities that cannot be removed in the general solid-liquid separation device used in the first separator 22 and the second separator 24 can be removed.

[0056] In addition, solid-liquid separation devices with different pore sizes are used in the first separator 22 and the third separator 26. A solid-liquid separation device with a larger pore size is used in the first separation step P22 where there are more impurities. This can prevent blockage of the first separator 22, and a solid-liquid separation device with a smaller pore size is used in the third separation step P26. This can remove trace impurities, thereby improving the efficiency of impurity removal.

[0057] In addition, the third separator 26 may also include a coarse filter such as a basket type coarse filter and an ultrafilter disposed downstream of the coarse filter. In this case, the coarse filter performs solid-liquid separation on the aqueous solution treated by the second dissolution step P25, and the ultrafilter performs ultrafiltration on the aqueous solution after passing through the coarse filter.

[0058] In the second crystallization step P27, a second crystallization is performed to precipitate lithium carbonate from the aqueous solution from which the solid component has been removed in the third separation step P26. The second crystallizer 27 has the same structure as the first crystallizer 23. The second crystallizer 27 may also be the same crystallizer as the first crystallizer 23. The second crystallizer 27 generates a slurry containing lithium carbonate.

[0059] In the 4th separation step P28, the slurry containing the lithium carbonate precipitated in the 2nd crystallization step P27 is subjected to the 4th solid-liquid separation. The 4th separator 28 has the same structure as the 2nd separator 24. The 4th separator 28 can also be the same solid-liquid separation device as the 2nd separator 24. The slurry is subjected to the solid-liquid separation by the 4th separator 28, thereby taking out the solid component containing lithium carbonate from the slurry as a recyclate. The remaining filtrate can be discarded or returned to the 1st dissolving tank 21 or the 2nd dissolving tank 25 again. In addition, when the filtrate is introduced into the 1st dissolving tank 21 or the 2nd dissolving tank 25, the filtrate can be introduced into the 1st dissolving tank 21 or the 2nd dissolving tank 25 after being cooled to room temperature by a heat exchanger.

[0060] Thus, according to the present embodiment, the calcined product generated by the thermal decomposition step P1 is ground by the grinder 20 before being introduced into the first dissolution tank 21. Thus, even if a part of the waste lithium ion battery calcined in the thermal decomposition step P1 becomes a block, the ground calcined product introduced into the first dissolution tank 21 becomes less than a predetermined average particle size. Therefore, it is possible to prevent the reduction of the dissolution rate of lithium in the first dissolution tank 21, thereby suppressing the reduction of the recovery rate of lithium. Alternatively, it is possible to increase the dissolution rate of lithium in the first dissolution tank 21, thereby increasing the recovery rate of lithium. Thus, according to the present embodiment, it is possible to perform appropriate dissolution treatment on the calcined waste lithium ion battery.

[0061] In addition, the amount of water required for dissolving the calcined product can be reduced, thereby making the dissolution equipment compact. In addition, the calcined product can be prevented from clogging the piping of the dissolution equipment, thereby reducing the maintenance cost such as manual cleaning.

[0062] In addition, in the 3rd separation process P26, the aqueous solution after being processed by the 2nd dissolving process P25 is subjected to the solid-liquid separation of ultrafiltration, thus the trace impurities that can not be removed in the 1st solid-liquid separation and the 2nd solid-liquid separation can be removed, thereby the purity of the lithium carbonate recovered can be further improved. Especially, by grinding for the roasted product, the amount of impurities such as nickel included by the solid component comprising lithium carbonate generated in the 2nd separation process P24 may increase. Therefore, by implementing ultrafiltration to the aqueous solution after making the solid component comprising lithium carbonate redissolve, impurities can be reliably removed.

[0063] Furthermore, by adjusting the average particle size of the calcined product after grinding introduced into the first dissolution tank 21 by the grinder 20, the size of impurities to be captured by the ultrafiltration membrane used in the third separation step P26 can be adjusted to a size corresponding to the pore size of the ultrafiltration membrane.

[0064] As mentioned above, although embodiment of this disclosure was described, this disclosure is not limited to the said embodiment, Various improvements, changes, and corrections can be made within the range which does not deviate from the summary.

[0065] [Other embodiments]

[0066] For example, in the above-mentioned embodiments, a processing system in which one or more devices or apparatuses correspond to each process is exemplified, but the processing system may be configured so that a plurality of processes are realized by one device or apparatus.

[0067] In addition, in the above-mentioned embodiment, the solid component containing lithium carbonate generated by the second separation step P24 is exemplified to be dissolved in water again, but the second dissolution step P25 to the fourth separation step P28 may not be provided. In this case, the lithium carbonate as a solid component obtained in the second separation step P24 becomes a recyclate.

[0068] In addition, in the above embodiment, an example is given in which the rotation speed of the rotating teeth 20d is predetermined in the pulverizer 20a of the grinder 20. In this way, the rotation speed of the rotating teeth 20d may be a fixed value set and input by the user, or the rotation speed of the rotating teeth 20d may be controlled according to the load condition of the grinder 20 based on the amount of roasted material fed into the grinder 20.

[0069] Figure 5 1 is a schematic diagram showing a system configuration for implementing a thermal decomposition step and a polishing step of a modified example of the present disclosure. Figure 2 The same reference numerals are used for the structures shown in the figure, and the description thereof is omitted. The processing system of this modified example includes a first controller 13e for controlling the rotary kiln 13 and a second controller 20m for controlling the grinder 20. The first controller 13e and the second controller 20m may also be configured as the same controller. The first controller 13e and the second controller 20m respectively include a first processing circuit 13f and a second processing circuit 20n for performing various signal processing.

[0070] The processing circuits 13f and 20n include, for example, computers such as microcontrollers, personal computers, and PLCs (Programmable Logic Controllers). More specifically, the processing circuits 13f and 20n include processors, memories, and peripheral circuits. The processors include, for example, CPUs or MPUs. The memories include ROMs, RAMs, registers, nonvolatile memories, and the like. The peripheral circuits include input and output interfaces, and the like. In addition, the controllers 13e and 20m may also include input devices for users to input operations and output devices such as monitors for outputting control states.

[0071] In addition, the functions of the elements disclosed in this specification can be performed using general-purpose processors, special-purpose processors, integrated circuits, ASICs (Application Specific Integrated Circuits), existing circuits, and / or circuits or processing circuits comprising combinations thereof that are configured or programmed to perform the disclosed functions. The processor contains transistors and other circuits and is therefore considered a processing circuit or circuits. In this specification, a circuit, unit, component, or part is hardware that performs the listed functions, or hardware that is programmed to perform the listed functions. The hardware may be the hardware disclosed in this specification, or it may be other known hardware that is programmed or configured to perform the listed functions. In the case where the hardware is a processor that is considered to be a type of circuit, the circuit, unit, or component is a combination of hardware and software, and the software is used to constitute the hardware and / or processor.

[0072] The memory stores a control program. The processor reads the control program from the memory and generates a command value for controlling the rotary kiln 13 or the grinding machine 20 as a control target according to the control program.

[0073] The first controller 13e controls the heater 13b in such a manner as to maintain the target temperature Ta of the heater 13b. The target temperature Ta of the heater 13b is set according to the first temperature determined as the roasting temperature of the waste LIB. Here, the roasting temperature of the roasted product for maximizing the dissolution rate of lithium in the roasted product when it is dissolved in the first dissolution step P21 varies according to the properties of the waste LIB. Therefore, the first temperature of the waste LIB roasted in the rotary kiln 13 can be changed according to the properties of the waste LIB. When the first temperature changes, the amount of agglomerates and the size of the agglomerates in the roasted product discharged from the rotary kiln 13 also change. As a result, in the grinder 20 into which the roasted product discharged from the rotary kiln 13 is introduced, the load condition of the crusher 20a changes according to the amount of agglomerates and the size of the agglomerates in the roasted product.

[0074] For example, the first controller 13e controls the target temperature Ta of the heater 13b of the rotary kiln 13 to be low, thereby lowering the first temperature. Alternatively, the first controller 13e controls the target temperature Ta of the heater 13b of the rotary kiln 13 to be high, thereby raising the first temperature. When the first temperature is low, the amount of agglomerates in the calcined material discharged from the rotary kiln 13 decreases, and the size of the agglomerates decreases. When the first temperature is high, the amount of agglomerates in the calcined material discharged from the rotary kiln 13 increases, and the size of the agglomerates increases.

[0075] When the rotation speed of the rotating teeth 20d of the pulverizer 20a is set to a fixed value, if the amount of agglomerates and the size of the agglomerates in the introduced calcined material vary greatly, the load of the pulverizer 20a will become too small or too large, and thus the efficiency will be poor. Therefore, the second controller 20m obtains the target temperature Ta of the heater 13b, and controls the rotation speed of the rotating teeth 20d according to the target temperature Ta of the heater 13b. Thus, in the pulverizer 20a of the grinder 20, the rotation speed of the rotating teeth 20d changes according to the amount of agglomerates and the size of the agglomerates in the calcined material introduced into the grinder 20.

[0076] For example, the second controller 20m controls the rotating teeth 20d such that the lower the target temperature Ta of the heater 13b, the lower the rotation speed of the rotating teeth 20d, and the higher the target temperature Ta of the heater 13b, the higher the rotation speed of the rotating teeth 20d.

[0077] In this way, the calcination temperature of the waste LIB, that is, the target temperature Ta of the heater 13b, changes according to the properties of the waste LIB introduced into the rotary kiln 13 disposed in the front stage of the grinder 20, and the rotation speed of the rotating teeth 20d of the grinder 20 is controlled by the target temperature Ta of the heater 13b. Thus, the pulverization force can be adjusted according to the load condition of the pulverizer 20a. Therefore, appropriate grinding corresponding to the amount of agglomerates or the size of the agglomerates in the calcined material introduced into the grinder 20 can be performed.

[0078] In addition, if Figure 3 As in the example of , when the rotating teeth 20d of the pulverizer 20a and the partition 20f of the classifier 20B rotate along the same rotation axis, when the rotation speed of the rotating teeth 20d increases, the rotation speed of the partition 20f also increases, and the average particle size of the roasted product discharged from the grinder 20 decreases. On the contrary, when the rotation speed of the rotating teeth 20d decreases, the rotation speed of the partition 20f also decreases, and the average particle size of the roasted product discharged from the grinder 20 increases. In this case, the lower limit and the upper limit of the rotation speed of the rotating teeth 20d based on the target temperature Ta of the heater 13b can also be set so that the average particle size of the roasted product discharged from the grinder 20 falls within the prescribed allowable range. When the rotation speed of the rotating teeth 20d of the crusher 20a and the rotation speed of the partition 20f of the classifier 20B can be set independently, the rotation speed of the rotating teeth 20d can be controlled according to the target temperature Ta of the heater 13b, and the rotation speed of the partition 20f can be set according to the average particle size to be discharged from the grinder 20.

[0079] [Public Summary]

[0080] [Solution 1]

[0081] A waste lithium ion battery processing system according to one embodiment of the present disclosure is a waste lithium ion battery processing system for recovering lithium from waste lithium ion batteries, wherein the waste lithium ion battery processing system comprises: a thermal decomposition system, which roasts the waste lithium ion batteries at a first temperature to generate a roasted product; a first dissolution tank, which immerses the roasted product in water; a first separator, which performs a first solid-liquid separation on the aqueous solution after immersion in the first dissolution tank; a first crystallizer, which performs a first crystallization to precipitate lithium carbonate from the aqueous solution separated by the first solid-liquid separation; a second separator, which performs a second solid-liquid separation on a slurry containing lithium carbonate precipitated by the first crystallization and recovers lithium carbonate; and a grinder, which grinds the roasted product in a manner such that the roasted product has an average particle size less than a predetermined average particle size before introducing the roasted product into the first dissolution tank.

[0082] According to the above structure, before the calcined product generated in the thermal decomposition system is introduced into the first dissolving tank, it is ground by a grinder. Thus, even if a part of the waste lithium-ion battery after calcination in the thermal decomposition system becomes a block, the ground calcined product introduced into the first dissolving tank becomes less than a predetermined average particle size. Therefore, it is possible to prevent the reduction of the dissolution rate of lithium in the first dissolving tank, thereby suppressing the reduction of the recovery rate of lithium. Alternatively, it is possible to increase the dissolution rate of lithium in the first dissolving tank, thereby increasing the recovery rate of lithium. In this way, according to this embodiment, the waste lithium-ion battery after calcination can be appropriately dissolved.

[0083] [Solution 2]

[0084] Alternatively, in the waste lithium-ion battery processing system of Scheme 1, the thermal decomposition system includes a heater, which heats the waste lithium-ion battery to the first temperature, and the grinder includes: a crusher having rotating teeth, which crushes the introduced calcined material by rotating the rotating teeth; a classifier, which classifies the calcined material crushed by the crusher; and a controller, which controls the rotation speed of the rotating teeth, the heater is configured to be able to change the first temperature by changing the target temperature, and the controller controls the rotation speed of the rotating teeth according to the target temperature of the heater.

[0085] According to the above structure, the rotation speed of the rotating teeth of the grinder is controlled by using the target temperature of the heater which changes according to the properties of the waste lithium-ion batteries introduced into the rotary kiln arranged in the front stage of the grinder, thereby enabling appropriate grinding corresponding to the amount of roasted material introduced into the grinder or the size of the block.

[0086] [Solution 3]

[0087] Alternatively, the waste lithium-ion battery treatment system of Scheme 1 or Scheme 2 comprises: a second dissolution tank, which immerses the solid component containing lithium carbonate separated by the second solid-liquid separation in water; a third separator, which performs a third solid-liquid separation using an ultrafiltration membrane on the aqueous solution after immersion in the second dissolution tank; a second crystallizer, which performs a second crystallization to precipitate lithium carbonate from the aqueous solution separated by the third solid-liquid separation; and a fourth separator, which performs a fourth solid-liquid separation on the slurry containing lithium carbonate precipitated by the second crystallization and recovers the lithium carbonate.

[0088] According to the above configuration, since solid-liquid separation using an ultrafiltration membrane is performed in the third separator, these impurities that could not be removed in the first separator and the second separator provided for the steps up to this point can be removed.

[0089] [Solution 4]

[0090] Alternatively, in the waste lithium-ion battery treatment system of Scheme 3, the third separator may include a coarse filter and an ultrafilter, and the ultrafilter may ultrafilter the aqueous solution after passing through the coarse filter.

[0091] [Solution 5]

[0092] Alternatively, in the waste lithium-ion battery processing system of any one of Schemes 1 to 4, the thermal decomposition system includes: a preheater, which heats the waste lithium-ion battery at a second temperature lower than the first temperature before roasting the waste lithium-ion battery in order to decompose and remove the electrolyte contained in the waste lithium-ion battery; a crusher, which crushes the waste lithium-ion battery after being heated at the second temperature; and a sorter, which separates the positive electrode active material from the positive electrode current collector of the crushed waste lithium-ion battery and sorts the positive electrode active material.

[0093] According to the above structure, after the electrolyte contained in the waste lithium-ion battery is rendered harmless by the preheater, the waste lithium-ion battery is crushed and sorted. By performing heating by the preheater before crushing and sorting, the electrolyte can be decomposed and removed to ensure safety in the crushing process. In addition, by roasting the waste lithium-ion battery after crushing and sorting, it is not necessary to heat the unnecessary parts such as the shell and current collector contained in the waste lithium-ion battery, which can suppress heat consumption.

[0094] [Solution 6]

[0095] Another aspect of the present invention discloses a method for treating waste lithium-ion batteries for recovering lithium from waste lithium-ion batteries, wherein the waste lithium-ion batteries are calcined at a first temperature to generate a calcined product, the calcined product is introduced into a first dissolution tank and immersed in water, a first solid-liquid separation is performed on the aqueous solution after immersion in the first dissolution tank, a first crystallization is performed to precipitate lithium carbonate from the aqueous solution separated by the first solid-liquid separation, a second solid-liquid separation is performed on a slurry containing lithium carbonate precipitated by the first crystallization to recover lithium carbonate, and before the calcined product is introduced into the first dissolution tank, the calcined product is ground in a manner such that the calcined product has an average particle size less than a predetermined average particle size.

Claims

1. A waste lithium ion battery processing system, which is used to recover lithium from waste lithium ion batteries, characterized in that: The waste lithium-ion battery treatment system has: A thermal decomposition system, which roasts the waste lithium-ion battery at a first temperature to generate a roasted product; a first dissolving tank for immersing the roasted product in water; a first separator for performing a first solid-liquid separation on the aqueous solution after immersion in the first dissolving tank; a first crystallizer for performing a first crystallization for precipitating lithium carbonate from the aqueous solution separated by the first solid-liquid separation; a second separator for performing a second solid-liquid separation on the slurry containing the lithium carbonate precipitated by the first crystallization and recovering the lithium carbonate; as well as A grinder grinds the calcined product so that the calcined product has an average particle size not larger than a predetermined average particle size before the calcined product is introduced into the first dissolution tank.

2. The waste lithium-ion battery processing system according to claim 1, characterized in that: The thermal decomposition system comprises a heater, which heats the waste lithium-ion battery to the first temperature. The grinding machine comprises: a pulverizer having rotating teeth, wherein the introduced calcined material is pulverized by the rotation of the rotating teeth; a classifier for classifying the roasted product after being crushed by the crusher; as well as a controller for controlling the rotation speed of the rotating teeth, The heater is configured to change the first temperature by changing the target temperature. The controller controls a rotation speed of the rotating teeth according to a target temperature of the heater.

3. The waste lithium-ion battery processing system according to claim 1 or 2, characterized in that: The waste lithium-ion battery treatment system has: a second dissolution tank for immersing the solid component containing lithium carbonate separated by the second solid-liquid separation in water; a third separator for performing a third solid-liquid separation using an ultrafiltration membrane on the aqueous solution after immersion in the second dissolution tank; a second crystallizer for performing a second crystallization of lithium carbonate from the aqueous solution separated by the third solid-liquid separation; and A fourth separator performs a fourth solid-liquid separation on the slurry containing the lithium carbonate precipitated by the second crystallization to recover the lithium carbonate.

4. The waste lithium-ion battery processing system according to claim 3, characterized in that: The third separator includes a coarse filter and an ultrafilter for ultrafiltering the aqueous solution after passing through the coarse filter.

5. The waste lithium-ion battery processing system according to claim 1 or 2, characterized in that: The thermal decomposition system comprises: a preheater for heating the waste lithium ion battery at a second temperature lower than the first temperature in order to decompose and remove the electrolyte contained in the waste lithium ion battery before roasting the waste lithium ion battery; a crusher for crushing the waste lithium-ion batteries heated at the second temperature; and A sorting machine separates the positive electrode active material from the crushed positive electrode current collector of the waste lithium ion battery and sorts the positive electrode active material.

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