A method for recovering lithium from spent lithium-ion battery electrode materials

Abstract

The application relates to the technical field of resource recycling, and particularly discloses a method for recycling lithium from waste lithium ion battery electrode materials. The method mixes the waste lithium ion battery electrode materials with a grinding aid, carries out activation grinding, and obtains grinding materials; the grinding materials are further treated to obtain lithium immersion liquid. According to the method, lithium is selectively and preferentially recycled from the waste lithium ion battery electrode materials, after mechanical-chemical grinding activation treatment, lithium is selectively and preferentially leached through water immersion, early separation of lithium and metals such as nickel, cobalt and manganese is realized, and the problem of high lithium loss rate caused by simultaneous leaching of valuable metals and subsequent lithium separation in a conventional wet recycling process is effectively solved.

Description

Technical Field

[0001] This invention relates to the field of resource recycling technology, and in particular to a method for recovering lithium from waste lithium-ion battery electrode materials. Background Technology

[0002] The rapid development of electric vehicles has led to a rapid increase in battery consumption. Lithium-ion batteries, as a typical representative of new energy power batteries, possess numerous advantages such as long cycle life, high specific energy, low self-discharge effect, small size, high operating voltage, no memory effect, wide operating temperature range, and environmental friendliness. Therefore, they are widely used in energy storage and electric vehicle fields. However, the average lifespan of an electric vehicle is 8-10 years. In the future, a large number of lithium-ion batteries will be retired and scrapped.

[0003] Waste lithium batteries contain valuable metals such as lithium, nickel, cobalt, manganese, copper, and aluminum, making them highly valuable for recycling. Among these, the cathode material has the highest recycling value. Existing mainstream recycling processes can be broadly categorized into three types: pyrometallurgical, hydrometallurgical, and biometallurgical processes. Hydrometallurgical processes, with their advantages of simple process flow, mild reaction conditions, environmental friendliness, and high recovery rates, are currently the mainstream method used in industry.

[0004] Traditional hydrometallurgical recovery processes typically involve leaching valuable metals (Li, Co, Ni, Mn, etc.) from the cathode material from the solid phase into a solution, and then recovering them from the solution through precipitation or extraction. The leaching process is the most critical step in the entire process, determining the extraction rates of each metal. In existing research, the leaching process usually uses inorganic acids (such as HCl, HNO3, H2SO4, etc.) or organic acids (such as malic acid, citric acid, ascorbic acid, etc.) to simultaneously dissolve valuable metals such as Li, Ni, Co, and Mn from the cathode material into the solution. Subsequently, extraction and back-extraction processes are used to separate and extract the metals from the leachate. Since the leachate may contain impurities (such as Fe, Cu, etc.), impurity removal is usually required before extraction and separation. In summary, current hydrometallurgical recovery processes are lengthy and cumbersome, especially since Li is recovered at the very end of the process. The impurity removal, extraction, and back-extraction processes at the beginning cause significant Li losses, resulting in low Li recovery rates.

[0005] If lithium can be selectively and preferentially leached from waste lithium batteries during the recycling process, reducing the introduction of other impurity metal ions, and prioritizing lithium extraction at the front end of the process, lithium loss can be effectively reduced. Furthermore, nickel, cobalt, and manganese elements are enriched in the lithium leaching residue, which can be subsequently recovered using conventional acid leaching methods. Patent application CN113684374A discloses a method for selectively extracting lithium from retired batteries. This method is based on the ion exchange between divalent manganese ions and lithium ions. The cathode material and divalent manganese salt are mixed in a certain proportion to prepare a slurry. A ball milling process thoroughly mixes the divalent manganese salt and the cathode material, effectively disrupting the crystal structure of the cathode material. This reduces the activation energy for the exchange between divalent manganese ions and lithium ions, significantly lowering the reaction energy required for subsequent lithium extraction. The ball-milled mixture is then calcined at a low temperature, allowing divalent manganese in the manganese salt to occupy lithium sites in the layered structure, directly resulting in manganese-lithium replacement and obtaining a pure lithium-containing leachate. The disadvantages of this method are: (1) the existing use of divalent manganese salts limits the source of raw materials; (2) after ball milling, roasting and leaching are required, which is a long process with high energy consumption and the roasting process will produce harmful gases.

[0006] Therefore, it is necessary to develop a new method for the selective and preferential recovery of lithium from waste lithium-ion battery electrode materials, which would be more conducive to the treatment of waste lithium-ion battery electrode materials. Summary of the Invention

[0007] The main technical problem solved by this invention is to provide a method for recovering lithium from waste lithium-ion battery electrode materials. This method can achieve preferential recovery of lithium from lithium-ion battery electrode materials and improve the lithium recovery rate.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for recovering lithium from waste lithium-ion battery electrode materials, the method comprising the following steps:

[0009] S1: Mix waste lithium-ion battery electrode materials with grinding aids, and then perform activation grinding to obtain the ground material;

[0010] S2: Process the ground material to obtain a lithium-impregnated solution; the processing method is as follows:

[0011] Direct solid-liquid separation of the ground material; or,

[0012] The ground material is then subjected to a selective lithium leaching reaction, followed by solid-liquid separation;

[0013] The liquid phase obtained from the process is the lithium immersion solution.

[0014] In one embodiment of the present invention, the grinding aid is a sulfate and / or chloride. The sulfate or chloride may contain water of crystallization.

[0015] In a preferred embodiment of the present invention, the sulfate includes nickel sulfate, cobalt sulfate, manganese sulfate, ferric sulfate, ferrous sulfate, aluminum sulfate, magnesium sulfate, calcium sulfate, copper sulfate, and ammonium sulfate.

[0016] In a preferred embodiment of the present invention, the chloride salt includes nickel chloride, cobalt chloride, manganese chloride, ferric chloride, ferrous chloride, aluminum chloride, magnesium chloride, calcium chloride, copper chloride, and ammonium chloride.

[0017] As a further preferred embodiment of the present invention, the grinding aid is selected from any one or two or more of nickel sulfate, manganese sulfate, ferrous sulfate, ferric chloride, and aluminum chloride.

[0018] In one embodiment of the present invention, the amount of the grinding aid is such that the ratio of the molar number of sulfate ions and the molar number of chloride ions in the grinding aid to the molar number of lithium ions contained in the waste lithium-ion battery electrode material should satisfy the following:

[0019]

[0020] Where, n (Li) Represents the number of moles of lithium ions contained in the electrode material of discarded lithium-ion batteries; This represents the number of moles of sulfate ions in the added grinding aid. This represents the number of moles of chloride ions in the added grinding aid.

[0021] Preferably, the amount of the grinding aid is such that the ratio of the molar number of sulfate ions and the molar number of chloride ions in the grinding aid to the molar number of lithium ions contained in the waste lithium-ion battery electrode material should satisfy the following:

[0022] More preferably, the amount of the grinding aid is such that the ratio of the molar number of sulfate ions and the molar number of chloride ions in the grinding aid to the molar number of lithium ions contained in the waste lithium-ion battery electrode material should satisfy the following:

[0023]

[0024] More preferably, the amount of the grinding aid is such that the ratio of the molar number of sulfate ions and the molar number of chloride ions in the grinding aid to the molar number of lithium ions contained in the waste lithium-ion battery electrode material should satisfy the following:

[0025]

[0026] As one embodiment of the present invention, when water is added to the mixed grinding system of the waste lithium-ion battery electrode material and the grinding aid, and the amount of water added is 0.8 to 20 times the mass of the waste lithium-ion battery electrode material, the resulting grinding material can be directly separated into solid and liquid to obtain lithium impregnation solution, or the grinding material can undergo a selective lithium leaching reaction, followed by solid-liquid separation to obtain lithium impregnation solution.

[0027] As one embodiment of the present invention, when no water is added or the amount of water added is less than 0.8 times the mass of the waste lithium-ion battery electrode material in the mixed grinding system of the waste lithium-ion battery electrode material and the grinding aid, the resulting ground material is subjected to a selective lithium leaching reaction, followed by solid-liquid separation to obtain a lithium leaching solution.

[0028] As one embodiment of the present invention, the direct solid-liquid separation of the grinding material includes: separating the grinding material into solid and liquid phases, collecting the filtrate, washing the filter cake with water, and combining the washing liquid with the filtrate to obtain a lithium immersion solution.

[0029] Preferably, the mass of the water used for washing the filter cake is 1 to 60 times the mass of the waste lithium-ion battery electrode material. The sum of the mass of the water used for washing the filter cake and the mass of water added to the mixed grinding system of the waste lithium-ion battery electrode material and the grinding aid is controlled within 100 times the mass of the waste lithium-ion battery electrode material being processed, preferably within 70 times, and more preferably within 60 times.

[0030] In one embodiment of the present invention, in step S1, the grinding time for activation grinding is controlled to be between 10 and 720 minutes. For example, the grinding time can be any value among 10 minutes, 20 minutes, 30 minutes, 50 minutes, 60 minutes, 100 minutes, 120 minutes, 180 minutes, 240 minutes, 360 minutes, and 720 minutes.

[0031] In one embodiment of the present invention, in step S1, the activation grinding is performed using a ball mill or a rod mill. For example, when using a ball mill, the ball-to-material ratio (i.e., the mass ratio of grinding balls to waste lithium-ion battery electrode material) is (1-100):1, and the ball mill speed is 10-1200 rpm. When using a large ball mill, the speed can be appropriately reduced, for example, the speed can be controlled to 10-50 rpm.

[0032] In one embodiment of the present invention, in step S2, when the ground material undergoes a selective lithium leaching reaction, the liquid-to-solid ratio of the reaction system is 1–100 mL / g, preferably 10–100 mL / g. For example, the liquid-to-solid ratio of the reaction system can be any value selected from 10 mL / g, 20 mL / g, 30 mL / g, 40 mL / g, 50 mL / g, 60 mL / g, 70 mL / g, 80 mL / g, 90 mL / g, and 100 mL / g.

[0033] In one embodiment of the present invention, in step S2, the reaction temperature of the leaching reaction is 10–99°C. For example, the reaction temperature can be room temperature (about 25°C), or any value among 45°C, 50°C, 55°C, 65°C, 75°C, 85°C, and 95°C.

[0034] In one embodiment of the present invention, in step S2, the leaching reaction time is 1 to 720 minutes, preferably 5 to 720 minutes. For example, the reaction time can be any value among 1 minute, 5 minutes, 10 minutes, 30 minutes, 60 minutes, 100 minutes, 120 minutes, 180 minutes, 240 minutes, 300 minutes, and 720 minutes.

[0035] In one embodiment of the present invention, during solid-liquid separation in step S2 to obtain a liquid lithium immersion solution, the solid obtained is lithium immersion slag; the lithium immersion solution is used to prepare lithium salts, and the lithium immersion slag is used to recover transition metal salts.

[0036] In one embodiment of the present invention, the waste lithium-ion battery electrode material is generated from one or more of the following: lithium nickel cobalt manganese oxide batteries, lithium cobalt oxide batteries, lithium manganese oxide batteries, and lithium nickel cobalt aluminum oxide batteries. The waste lithium-ion battery electrode material is preferably a positive electrode material.

[0037] The present invention provides a method for recovering lithium from waste lithium-ion battery electrode materials. This method employs mechanochemical grinding and activation treatment of the waste lithium-ion battery electrode materials. Sulfate or chloride salts added during the activation process act as grinding aids, enabling selective and preferential leaching of lithium from the waste lithium-ion battery electrode materials. The process is simple. After selective lithium leaching, lithium elements in the cathode material are fully leached into the solution, yielding a lithium leaching solution. Transition metals such as nickel, cobalt, and manganese remain in the lithium leaching residue as insoluble oxides, resulting in a lithium-rich lithium leaching solution and a lithium leaching residue rich in transition metal elements. These can be used to produce lithium salts and recover transition metals, respectively, achieving selective and preferential separation of lithium from lithium-ion battery electrode materials and efficient recovery of both lithium and transition metal elements.

[0038] The principle of this invention will be explained below using the treatment of waste lithium-ion battery electrode materials generated from the processing of lithium cobalt oxide (LiCoO2) batteries as an example, wherein nickel sulfate (NiSO4) is used as the grinding aid.

[0039] The electrode material, lithium cobalt oxide crystal, has a regular layered structure with atoms arranged in the order -O-Li-O-Co-. It can be considered as being composed of Li2O and Co2O3. Among them, Li2O is highly reactive and readily generates LiOH in the presence of water (which may be water of crystallization). It then reacts with NiSO4 to generate Li2SO4 and Ni(OH)2, i.e., the following reaction occurs:

[0040] Li₂O + H₂O = 2LiOH;

[0041] 2LiOH+NiSO4=Li2SO4+Ni(OH)2.

[0042] Due to the regular arrangement of ions in lithium cobalt oxide, lithium ions are confined within the crystal lattice, making it difficult for most lithium ions to directly contact water and react with grinding aids. This invention uses grinding (e.g., ball milling) to disrupt the crystal structure of lithium cobalt oxide, continuously exposing lithium ions to react with water and grinding aids until all lithium ions are converted into soluble lithium salts. Simultaneously, the metal ions in the grinding aids are converted into precipitates. Compared to lithium ions, cobalt, or Co₂O₃, in lithium cobalt oxide is less likely to react with water to form hydroxides such as Co(OH)₂ or Co(OH)₃, and therefore less likely to be converted into soluble cobalt salts during grinding, thus achieving selective leaching of lithium.

[0043] When the waste lithium-ion battery electrode materials being processed come from lithium nickel cobalt manganese oxide batteries, lithium manganese oxide batteries, or lithium nickel cobalt aluminum oxide batteries, the reaction principle is similar to that of lithium cobalt oxide batteries described above, and will not be repeated here. The reaction principle is also similar when other grinding aids are used, and will not be repeated here either.

[0044] The method of this invention selectively and preferentially recovers lithium from waste lithium-ion battery electrode materials. Through mechanical and chemical grinding and activation treatment, lithium is selectively and preferentially leached, realizing the early separation of lithium from metals such as nickel, cobalt, and manganese. This effectively solves the problem of high lithium loss rate caused by the simultaneous leaching of valuable metals and subsequent lithium separation in conventional wet recycling processes. At the same time, the lithium leaching process of this invention does not use any reducing agent, but only water as the leaching agent, and there is no need for roasting, which reduces energy consumption.

[0045] Compared with the existing selective lithium impregnation process of ball milling and mixing divalent manganese salts followed by calcination, the process of this invention is shorter, requires no calcination, consumes less energy, and utilizes a wide variety of grinding aids from diverse sources. Therefore, this method represents an important technological direction for the future recycling of waste lithium batteries, possessing extremely high potential for industrial application and practical value. Attached Figure Description

[0046] Figure 1 This is a process flow diagram of a method for recovering lithium from waste lithium-ion battery electrode materials provided by the present invention;

[0047] Figure 2 This is a process flow diagram of another method for recovering lithium from waste lithium-ion battery electrode materials provided by the present invention. Detailed Implementation

[0048] The technical solution of the present invention will be described in detail below through specific embodiments. These embodiments are intended to further illustrate the content of the present invention, but are not intended to limit the scope of protection of the claims of the present invention.

[0049] In the following examples, all pharmaceutical agents used are commercially available products. Unless otherwise specified, all percentages of content in the examples are by mass.

[0050] Example 1

[0051] This embodiment provides a method for recovering lithium from waste lithium-ion battery electrode materials. The process flow diagram of the method is shown below. Figure 1 As shown in Table 1, the waste lithium-ion battery electrode material being processed is the positive electrode material generated from the processing of ternary nickel-cobalt-manganese lithium batteries, and its metal element composition is shown in Table 1.

[0052] Table 1

[0053] Content, wt% 4.84％ 18.82％ 6.06％ 5.94％

[0054] The specific steps of the processing method are as follows:

[0055] S1: 10g of waste lithium-ion battery electrode material powder, 20g of water, and 10.08g of nickel sulfate (NiSO4·6H2O) were put into a ball mill for mechanical and chemical activation grinding. The ball-to-material ratio was 10:1 and the ball mill speed was 500rpm. After grinding and activation treatment for 240 minutes, a grinding slurry was obtained.

[0056] The molar number of lithium ions in the waste lithium-ion battery electrode material powder raw material and the molar number of sulfate ions in the added nickel sulfate conform to the following formula:

[0057]

[0058] S2: Transfer the grinding slurry to a stirred reactor, add water until the liquid-to-solid ratio of the reactants is 10 mL / g, stir to carry out the selective leaching reaction of lithium, the leaching reaction time is 10 minutes, and the reaction temperature is room temperature (about 25°C).

[0059] S3: After the leaching reaction is completed, the resulting slurry is subjected to solid-liquid separation, and the filter cake is washed with 300 mL of water to obtain lithium leaching solution and lithium leaching residue, respectively.

[0060] The resulting lithium leaching solution is used to prepare lithium salts, and the lithium leaching residue is used to recover transition metal salts. Both the preparation of lithium salts from the resulting lithium leaching solution and the recovery of transition metal salts from the lithium leaching residue can be carried out using existing methods, and this invention is not limited in this regard. For example, the recovery of transition metal salts from the lithium leaching residue can be achieved using conventional acid leaching methods.

[0061] In this embodiment, the lithium leaching solution was detected by inductively coupled plasma optical emission spectroscopy (ICP-OES) and calculated to have a lithium leaching rate of 94.43%, and leaching rates of nickel, cobalt, and manganese of 1.23%, 2.36%, and 2.89%, respectively. The lithium leaching solution mainly contains lithium and has low content of impurity elements.

[0062] X-ray diffraction (XRD) analysis revealed that the main phases of the lithium-leaching slag were graphite and oxides of nickel, cobalt, and manganese.

[0063] Example 2

[0064] This embodiment provides a method for recovering lithium from waste lithium-ion battery electrode materials. The process flow diagram of the method is shown below. Figure 1 As shown, the treated waste lithium-ion battery electrode materials are the same as in Example 1.

[0065] The specific steps of the processing method are as follows:

[0066] S1: 20g of waste lithium-ion battery electrode material powder, 80g of water, and 12.96g of manganese sulfate (MnSO4·H2O) were put into a ball mill for mechanical and chemical activation grinding. The ball-to-material ratio was 5:1 and the ball mill speed was 500rpm. After grinding and activation treatment for 360 minutes, a grinding slurry was obtained.

[0067] The molar number of lithium in the waste lithium-ion battery electrode material powder raw material and the molar number of sulfate ions in the added manganese sulfate conform to the following formula:

[0068]

[0069] S2: Transfer the grinding slurry to a stirred reactor, add water until the liquid-to-solid ratio of the reactants is 50 mL / g, stir to carry out the selective leaching reaction of lithium, the leaching reaction time is 5 minutes, and the reaction temperature is room temperature (about 25°C).

[0070] S3: After the leaching reaction is completed, the resulting slurry is subjected to solid-liquid separation, and the filter cake is washed with 200 mL of water to obtain lithium leaching solution and lithium leaching residue. The lithium leaching solution is used to prepare lithium salts, and the lithium leaching residue is used to recover transition metal salts.

[0071] In this embodiment, the lithium leaching solution was detected by inductively coupled plasma optical emission spectroscopy (ICP-OES) and calculated to have a lithium leaching rate of 98.68%, and nickel, cobalt and manganese leaching rates of 0.05%, 0.27% and 0.82% respectively. The lithium leaching solution mainly contains lithium and has low content of impurity elements.

[0072] X-ray diffraction (XRD) analysis revealed that the main phases of the lithium-leaching slag were graphite and oxides of nickel, cobalt, and manganese.

[0073] Example 3

[0074] This embodiment provides a method for recovering lithium from waste lithium-ion battery electrode materials. The process flow diagram of the method is shown below. Figure 1 As shown in Table 2, the waste lithium-ion battery electrode material being processed is a positive electrode material produced from the processing of lithium cobalt oxide batteries, and its metal element composition is shown in Table 2.

[0075] Table 2

[0076] Content, wt% 4.72％ 38.95％

[0077] The specific steps of the processing method are as follows:

[0078] S1: 10g of waste lithium-ion battery electrode material powder and 6.71g of ferric chloride (FeCl3·6H2O) were put into a ball mill for mechanical and chemical activation grinding. The ball-to-material ratio was 1:1 and the ball mill speed was 800rpm. After grinding and activation treatment for 720 minutes, the ground material was obtained.

[0079] The molar number of lithium ions in the waste lithium-ion battery electrode material powder raw material and the molar number of chloride ions in the added ferric chloride conform to the following formula:

[0080]

[0081] S2: Transfer the ground material to a stirred reactor, add water until the liquid-to-solid ratio of the reactants is 100 mL / g, stir to carry out the selective leaching reaction of lithium, the leaching reaction time is 720 minutes, and the reaction temperature is 50℃.

[0082] S3: After the leaching reaction is completed, the resulting slurry is subjected to solid-liquid separation, and the filter cake is washed with 200 mL of water to obtain lithium leaching solution and lithium leaching residue. The lithium leaching solution is used to prepare lithium salts, and the lithium leaching residue is used to recover transition metal salts.

[0083] In this embodiment, the lithium leaching solution was detected by inductively coupled plasma optical emission spectroscopy (ICP-OES) and calculated to have a lithium leaching rate of 89.54% and a cobalt leaching rate of 1.21%. The lithium leaching solution mainly contains lithium and has low levels of impurity elements.

[0084] X-ray diffraction (XRD) analysis revealed that the main phases of the lithium leaching slag were graphite and oxides of iron and cobalt.

[0085] Example 4

[0086] This embodiment provides a method for recovering lithium from waste lithium-ion battery electrode materials. The process flow diagram of the method is shown below. Figure 1 As shown in Table 3, the waste lithium-ion battery electrode material being processed is a positive electrode material produced from the processing of lithium cobalt oxide batteries, and its metal element composition is shown in Table 3.

[0087] Table 3

[0088] Content, wt% 3.37％ 26.94％

[0089] The specific steps of the processing method are as follows:

[0090] S1: 10g of waste lithium-ion battery electrode material powder, 200g of water, and 4.28g of aluminum chloride (AlCl3·6H2O) were put into a ball mill for mechanical and chemical activation grinding. The ball-to-material ratio was 80:1 and the ball mill speed was 500rpm. After grinding and activation treatment for 180 minutes, a grinding slurry was obtained.

[0091] The molar number of lithium ions in the waste lithium-ion battery electrode material powder raw material and the molar number of chloride ions in the added aluminum chloride conform to the following formula:

[0092]

[0093] S2: Transfer the grinding slurry to a stirred reactor. The liquid-to-solid ratio of the reactants is 20 mL / g. Stir to carry out the selective leaching reaction of lithium. The leaching reaction time is 720 minutes and the reaction temperature is room temperature (about 25°C).

[0094] S3: After the leaching reaction is completed, the resulting slurry is subjected to solid-liquid separation, and the filter cake is washed with 200 mL of water to obtain lithium leaching solution and lithium leaching residue. The lithium leaching solution is used to prepare lithium salts, and the lithium leaching residue is used to recover transition metal salts.

[0095] In this embodiment, the lithium leaching solution was detected by inductively coupled plasma optical emission spectroscopy (ICP-OES) and calculated to have a lithium leaching rate of 97.32% and a cobalt leaching rate of 1.73%. The lithium leaching solution mainly contains lithium and has low levels of impurity elements.

[0096] X-ray diffraction (XRD) analysis revealed that the main phases of the lithium leaching slag were graphite and oxides of aluminum and cobalt.

[0097] Example 5

[0098] This embodiment provides a method for recovering lithium from waste lithium-ion battery electrode materials. The process flow diagram of the method is shown below. Figure 1 As shown, the waste lithium-ion battery electrode materials are treated in the same way as in Example 4, and the specific steps of the treatment method are as follows:

[0099] S1: 50g of waste lithium-ion battery electrode material powder, 250g of water, and 37.12g of ferrous sulfate (FeSO4·7H2O) were put into a ball mill for mechanical and chemical activation grinding. The ball-to-material ratio was 10:1 and the ball mill speed was 1200rpm. After grinding and activation treatment for 10 minutes, a grinding slurry was obtained.

[0100] The molar number of lithium ions in the waste lithium-ion battery electrode material powder raw material and the molar number of sulfate ions in the added ferrous sulfate conform to the following formula:

[0101]

[0102] S2: Transfer the grinding slurry to a stirred reactor, adjust the liquid-solid ratio of the reactants to 10 mL / g with water, and carry out the selective leaching reaction of lithium by stirring. The leaching reaction time is 180 minutes and the reaction temperature is room temperature (about 25°C).

[0103] S3: After the leaching reaction is completed, the resulting slurry is subjected to solid-liquid separation, and the filter cake is washed with 300 mL of water to obtain lithium leaching solution and lithium leaching residue. The lithium leaching solution is used to prepare lithium salts, and the lithium leaching residue is used to recover transition metal salts.

[0104] In this embodiment, the lithium leaching solution was detected by inductively coupled plasma optical emission spectroscopy (ICP-OES) and calculated to have a lithium leaching rate of 95.21% and a cobalt leaching rate of 0.89%. The lithium leaching solution mainly contains lithium and has low levels of impurity elements.

[0105] X-ray diffraction (XRD) analysis revealed that the main phases of the lithium leaching slag were graphite and oxides of iron and cobalt.

[0106] Example 6

[0107] This embodiment provides a method for recovering lithium from waste lithium-ion battery electrode materials. The process flow diagram of the method is shown below. Figure 1 As shown in Table 4, the waste lithium-ion battery electrode material being processed is a positive electrode material produced from the processing of lithium manganese oxide batteries, and its metal element composition is shown in Table 4.

[0108] Table 4

[0109] Content, wt% 3.71％ 57.73％

[0110] The specific steps of the processing method are as follows:

[0111] S1: 50g of waste lithium-ion battery electrode material powder, 250g of water, and 44.58g of ferrous sulfate (FeSO4·7H2O) were put into a ball mill for mechanical and chemical activation grinding. The ball-to-material ratio was 10:1 and the ball mill speed was 500rpm. After grinding and activation treatment for 120 minutes, a grinding slurry was obtained.

[0112] The molar number of lithium ions in the waste lithium-ion battery electrode material powder raw material and the molar number of sulfate ions in the added ferrous sulfate conform to the following formula:

[0113]

[0114] S2: Transfer the grinding slurry to a stirred reactor, adjust the liquid-solid ratio of the reactants to 50 mL / g with water, and carry out the selective leaching reaction of lithium by stirring. The leaching reaction time is 300 minutes and the reaction temperature is 95℃.

[0115] S3: After the leaching reaction is completed, the resulting slurry is subjected to solid-liquid separation, and the filter cake is washed with 200 mL of water to obtain lithium leaching solution and lithium leaching residue. The lithium leaching solution is used to prepare lithium salts, and the lithium leaching residue is used to recover transition metal salts.

[0116] In this embodiment, the lithium leaching solution was detected by inductively coupled plasma optical emission spectroscopy (ICP-OES) and calculated to have a lithium leaching rate of 98.76% and a manganese leaching rate of 2.01%. The lithium leaching solution mainly contains lithium and has low levels of impurity elements.

[0117] X-ray diffraction (XRD) analysis revealed that the main phases of the lithium leaching residue were graphite and oxides of iron and manganese.

[0118] Example 7

[0119] This embodiment provides a method for recovering lithium from waste lithium-ion battery electrode materials. The process flow diagram of the method is shown below. Figure 2 As shown, the waste lithium-ion battery electrode materials are treated in the same way as in Example 3, and the specific steps of the treatment method are as follows:

[0120] S1: 10g of waste lithium-ion battery electrode material powder, 10g of water, and 10.4g of ferrous sulfate (FeSO4·7H2O) were placed into a grinding equipment for mechanical and chemical activation grinding. The grinding equipment used was a ball mill, the ball-to-material ratio was 30:1, the ball mill speed was 350rpm, and after grinding and activation treatment for 240 minutes, a grinding slurry was obtained.

[0121] The molar number of lithium ions in the waste lithium-ion battery electrode material powder raw material and the molar number of sulfate ions in the added ferrous sulfate conform to the following formula:

[0122]

[0123] S2: The obtained slurry is directly filtered and separated, and the filter cake is washed with 500 mL of water to obtain lithium leaching solution and lithium leaching residue. The lithium leaching solution is used to prepare lithium salts, and the lithium leaching residue is used to recover transition metal salts.

[0124] In this embodiment, the lithium leaching solution was detected by inductively coupled plasma optical emission spectroscopy (ICP-OES) and calculated to have a lithium leaching rate of 92.33% and a cobalt leaching rate of 0.86%. The lithium leaching solution mainly contains lithium and has low levels of impurity elements.

[0125] X-ray diffraction (XRD) analysis revealed that the main phases of the lithium leaching slag were graphite and oxides of iron and cobalt.

[0126] Example 8

[0127] This embodiment provides a method for recovering lithium from waste lithium-ion battery electrode materials. The process flow diagram of the method is shown below. Figure 1 As shown, the waste lithium-ion battery electrode materials are treated in the same way as in Example 3, and the specific steps of the treatment method are as follows:

[0128] S1: 10g of waste lithium-ion battery electrode material powder and 10.4g of ferrous sulfate (FeSO4·7H2O) were put into a ball mill for mechanical and chemical activation grinding. The ball-to-material ratio was 30:1 and the ball mill speed was 350rpm. After grinding and activation treatment for 240 minutes, the ground material was obtained.

[0129] The molar number of lithium ions in the waste lithium-ion battery electrode material powder raw material and the molar number of sulfate ions in the added ferrous sulfate conform to the following formula:

[0130]

[0131] S2: Transfer the ground material to a stirred reactor, add water until the liquid-to-solid ratio of the reactants is 20 mL / g, stir to carry out the selective leaching reaction of lithium, the leaching reaction time is 240 minutes, and the reaction temperature is 95℃;

[0132] S3: After the leaching reaction is completed, the resulting slurry is filtered and separated, and the filter cake is washed with 400 mL of water to obtain lithium leaching solution and lithium leaching residue. The lithium leaching solution is used to prepare lithium salts, and the lithium leaching residue is used to recover transition metal salts.

[0133] In this embodiment, the lithium leaching solution was detected by inductively coupled plasma optical emission spectroscopy (ICP-OES) and calculated to have a lithium leaching rate of 95.76% and a cobalt leaching rate of 1.41%. The lithium leaching solution mainly contains lithium and has low levels of impurity elements.

[0134] X-ray diffraction (XRD) analysis revealed that the main phases of the lithium leaching slag were graphite and oxides of iron and cobalt.

[0135] Comparative Example 1

[0136] This comparative example provides a method for recovering lithium from waste lithium-ion battery electrode materials. The process flow diagram of the method is shown below. Figure 1 As shown, the waste lithium-ion battery electrode materials are treated in the same way as in Example 5, and the specific steps of the treatment method are as follows:

[0137] S1: 50g of waste lithium-ion battery electrode material powder, 250g of water, and 101.2g of ferrous sulfate (FeSO4·7H2O) were put into a ball mill for mechanical and chemical activation grinding. The ball-to-material ratio was 10:1 and the ball mill speed was 1200rpm. After grinding and activation treatment for 10 minutes, a grinding slurry was obtained.

[0138] The molar number of lithium ions in the waste lithium-ion battery electrode material powder raw material and the molar number of sulfate ions in the added ferrous sulfate conform to the following formula:

[0139]

[0140] S2: Transfer the grinding slurry to a stirred reactor, adjust the liquid-solid ratio of the reactants to 10 mL / g with water, and carry out the selective leaching reaction of lithium by stirring. The leaching reaction time is 180 minutes and the reaction temperature is room temperature (about 25°C).

[0141] S3: After the leaching reaction is completed, the resulting slurry is subjected to solid-liquid separation, and the filter cake is washed with 300 mL of water to obtain lithium leaching solution and lithium leaching residue. The lithium leaching solution is used to prepare lithium salts, and the lithium leaching residue is used to recover transition metal salts.

[0142] In this comparative example, the lithium leaching solution was detected by inductively coupled plasma optical emission spectroscopy (ICP-OES), and the leaching rate of lithium was calculated to be 98.68% and that of cobalt was 96.36%. The high leaching rates of both lithium and cobalt indicate that the leaching process is not selective and has not achieved preferential selective leaching of lithium.

[0143] X-ray diffraction (XRD) analysis revealed that the main phases of the lithium-leaching slag were graphite and iron oxides.

[0144] The comparative examples show that the amount of grinding aid added has a significant impact on the selective leaching effect of lithium. Experiments revealed that when... At that time, the leaching rate of transition metals begins to rise. When the threshold is 3, the leaching rate of transition metals can be almost equivalent to that of lithium, meaning that lithium and transition metals are almost leached simultaneously, but the effect of selectively leaching lithium cannot be achieved.

[0145] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for recovering lithium from waste lithium-ion battery electrode materials, characterized in that, The method includes the following steps: S1: The waste lithium-ion battery electrode material is mixed with a grinding aid and then activated and ground. The activation and grinding is carried out using a ball mill or a rod mill to obtain the ground material. The waste lithium-ion battery electrode material is produced by processing any one or more of the following: lithium nickel cobalt manganese oxide batteries, lithium cobalt oxide batteries, lithium manganese oxide batteries, and lithium nickel cobalt aluminum oxide batteries. The grinding aid is a sulfate and / or chloride salt; wherein the sulfate includes nickel sulfate, cobalt sulfate, manganese sulfate, ferric sulfate, ferrous sulfate, aluminum sulfate, magnesium sulfate, calcium sulfate, copper sulfate, and ammonium sulfate; the chloride includes nickel chloride, cobalt chloride, manganese chloride, ferric chloride, ferrous chloride, aluminum chloride, magnesium chloride, calcium chloride, copper chloride, and ammonium chloride; the sulfate or chloride salt may contain water of crystallization or not. The amount of the grinding aid is such that the ratio of the molar number of sulfate ions and the molar number of chloride ions in the grinding aid to the molar number of lithium ions contained in the waste lithium-ion battery electrode material should satisfy the following: ; S2: Process the ground material to obtain a lithium-impregnated solution; the processing method is as follows: Direct solid-liquid separation of the ground material; or, The ground material is then subjected to a selective lithium leaching reaction, followed by solid-liquid separation; The liquid phase obtained from the process is the lithium immersion solution; When water is added to the mixed grinding system of the waste lithium-ion battery electrode material and the grinding aid, and the amount of water added is 0.8 to 20 times the mass of the waste lithium-ion battery electrode material, the resulting grinding material is directly subjected to solid-liquid separation to obtain lithium impregnation solution, or the grinding material is subjected to a selective lithium leaching reaction, followed by solid-liquid separation to obtain lithium impregnation solution. In the mixed grinding system of the waste lithium-ion battery electrode material and the grinding aid, no water is added or the amount of water added is less than 0.8 times the mass of the waste lithium-ion battery electrode material. The resulting ground material is then subjected to a selective lithium leaching reaction, followed by solid-liquid separation to obtain a lithium leaching solution.

2. The method according to claim 1, characterized in that, The grinding aid is selected from any one or two or more of nickel sulfate, manganese sulfate, ferrous sulfate, ferric chloride, and aluminum chloride.

3. The method according to claim 1, characterized in that, The amount of the grinding aid is such that the ratio of the molar number of sulfate ions and the molar number of chloride ions in the grinding aid to the molar number of lithium ions contained in the waste lithium-ion battery electrode material should satisfy the following: .

4. The method according to claim 1, characterized in that, The direct solid-liquid separation of the grinding material includes: separating the grinding material into solid and liquid phases, collecting the filtrate, washing the filter cake with water, and combining the washing liquid with the filtrate to obtain the liquid phase, which is the lithium immersion solution.

5. The method according to claim 1, characterized in that, In step S1, the grinding time for activation grinding is controlled to be 10~720 minutes.

6. The method according to claim 1, characterized in that, In step S2, when the ground material undergoes a selective lithium leaching reaction, the liquid-to-solid ratio of the reaction system is 1~100mL / g.

7. The method according to claim 6, characterized in that, In step S2, when the ground material undergoes a selective lithium leaching reaction, the liquid-to-solid ratio of the reaction system is 10~100mL / g.

8. The method according to claim 6, characterized in that, In step S2, the leaching reaction temperature is 10–99°C, and / or the leaching reaction time is 1–720 minutes.

9. The method according to claim 1, characterized in that, In step S2, during solid-liquid separation to obtain a liquid lithium immersion solution, the separated solid is lithium immersion residue; the lithium immersion solution is used to prepare lithium salts, and the lithium immersion residue is used to recover transition metal salts.

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