A method for extracting lithium from waste lithium-ion batteries

Abstract

The application provides a method for extracting lithium from waste lithium ion batteries, which comprises the following steps: 1) mixing a positive electrode material to be extracted and a phenolic compound, and then performing wet grinding treatment to obtain wet material; 2) performing roasting treatment on the wet material to obtain roasting material; and 3) mixing the roasting material with water to obtain a lithium-rich leaching solution; wherein the roasting treatment in step 2) is performed at a temperature of no less than 300 DEG C. The method can selectively leach lithium and preferentially extract lithium, improves the lithium extraction efficiency, does not introduce other impurity ions in the lithium extraction process, and does not produce waste gas pollution, and is environmentally friendly.

Description

TECHNICAL FIELD

[0001] The application relates to a lithium extraction method, in particular to a method for extracting lithium from waste lithium ion batteries, and belongs to the field of secondary batteries. BACKGROUND

[0002] In order to cope with the aggravation of environmental pollution and the crisis of fossil energy, countries around the world have accelerated the development of new energy vehicles. With the implementation of various new energy vehicle development strategies, new energy vehicles are rapidly becoming the core of the development of the automobile industry. Lithium ion power batteries are one of the key components of new energy vehicles, and the use cycle is lower than the life cycle of the whole vehicle. With the vigorous promotion of the development of new energy vehicles by the country, a large number of retired power lithium batteries will be produced. On the one hand, retired power lithium batteries contain heavy metals, toxic electrolytes and other components, which will pollute the environment if not properly treated. On the other hand, retired power lithium ion batteries contain a large amount of valuable metals such as lithium, nickel and cobalt. If the valuable metals can be recovered from retired power lithium ion batteries and recycled, it will greatly alleviate the dependence of rare metal resources on foreign countries and ensure the safety of raw material supply for the manufacture of power lithium ion batteries for new energy vehicles. Therefore, it is crucial to reasonably and efficiently recover valuable metals from retired power lithium ion batteries.

[0003] The current lithium extraction method mostly uses strong acid as the extracting agent, but a large amount of waste acid and waste gas will be produced, and nickel, cobalt and manganese metals will also be leached out at the same time, resulting in the inability to achieve efficient lithium extraction. The ion exchange between divalent manganese ions and lithium ions can greatly improve the leaching rate and selectivity of lithium by manganese-lithium replacement, but the divalent manganese salt used in this method will produce corresponding waste gas, causing environmental pollution problems, and the introduction of a large amount of manganese impurities in the system will affect the purity of lithium liquid.

[0004] Therefore, it is of great significance to develop a selective lithium extraction method with high lithium extraction efficiency, no introduction of other impurity ions and environmental friendliness. SUMMARY

[0005] The application provides a method for extracting lithium from waste lithium ion batteries, which can selectively leach lithium and improve the lithium extraction efficiency, and no other impurity ions are introduced during the lithium extraction process, and no waste gas pollution is produced, which is environmentally friendly.

[0006] The application provides a method for extracting lithium from waste lithium ion batteries, which comprises the following steps:

[0007] 1) mixing the to-be-extracted positive electrode material and the phenolic compound and then performing wet grinding treatment to obtain wet material;

[0008] 2) performing roasting treatment on the wet material to obtain roasted material;

[0009] 3) mixing the calcined material with water to obtain a lithium-rich leaching solution;

[0010] In step 2), the temperature of the calcination treatment is not less than 300°C.

[0011] The method for extracting lithium from waste lithium-ion batteries as described above, wherein the phenolic compound is at least one of phenol, hydroquinone, and phloroglucinol.

[0012] The method for extracting lithium from waste lithium-ion batteries as described above, wherein the mass ratio of the positive electrode material to be extracted and the phenolic compound is 1:(0.9-1.3).

[0013] The method for extracting lithium from waste lithium-ion batteries as described above, wherein the heating rate of the calcination is 5°C / min-10°C / min, the temperature is 300°C-500°C, and the time is 30 min-90 min.

[0014] The method for extracting lithium from waste lithium-ion batteries as described above, wherein the solvent used in the wet grinding treatment is water, and the mass ratio of the mixture of the positive electrode material to be extracted and the phenolic compound to water is 1:0.8-1:1.2. The rotation speed of the wet grinding treatment is 150 r / min-300 r / min, and the time is 20 min-60 min.

[0015] The method for extracting lithium from waste lithium-ion batteries as described above, wherein the mass-volume ratio of the calcined material to water is (80-160) g:1 L.

[0016] The method for extracting lithium from waste lithium-ion batteries as described above, wherein in step 3), the mixed system is heated in a water bath until the temperature of the mixed system is 30°C-70°C, and then the mixed system is stirred to obtain the lithium-rich leaching solution.

[0017] The method for extracting lithium from waste lithium-ion batteries as described above, wherein the rotation speed of the stirring is 100 r / min-300 r / min, and the time is 30 min-70 min.

[0018] The method for extracting lithium from waste lithium-ion batteries as described above, wherein the positive electrode material to be extracted is at least one of LiCoO2, Li2MnO4, LiNi x Co y Mn z O2, and x+y+z=1.

[0019] The method for extracting lithium from waste lithium-ion batteries as described above, further comprising step 4): after the concentration treatment of the lithium-rich leaching solution, mixing the concentrated system with a precipitant solution to obtain a lithium-containing compound.

[0020] In the present application, the reduction of the benzene ring can destroy the layered structure of the cathode material to be extracted, so that lithium is removed from the interlayer and reacts with the reducing agent to form a soluble lithium salt, which is stirred and leached in an aqueous solution to obtain a lithium-rich leaching solution with very low impurity metal ion content. Moreover, no other impurities that are not easy to volatilize are introduced during the lithium extraction process, and no waste gas is generated during the lithium extraction process, which is environmentally friendly and realizes efficient resource recycling of waste lithium ion batteries with low pollution. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 A flowchart of the method for extracting lithium from waste lithium ion batteries according to the present application. DETAILED DESCRIPTION

[0022] To make the purpose, technical scheme and advantages of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below in combination with the drawings and embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0023] The present application provides a method for extracting lithium from waste lithium ion batteries, which combines Figure 1 as shown, comprising the following steps:

[0024] 1) mixing the cathode material to be extracted and the phenolic compound and then performing wet grinding treatment to obtain wet material;

[0025] 2) performing calcination treatment on the wet material to obtain calcined material;

[0026] 3) mixing the calcined material with water to obtain a lithium-rich leaching solution;

[0027] In step 2), the calcination treatment has a temperature not lower than 300°C.

[0028] Specifically, in step 1), the mixing step of the cathode material to be extracted and the phenolic compound is not limited too much, and the cathode material to be extracted can be first added to the phenolic compound for mixing, or the phenolic compound can be added to the cathode material to be extracted for mixing.

[0029] In the present application, after the cathode material to be extracted and the phenolic compound are mixed, wet grinding treatment is performed to fully mix the cathode material to be extracted and the phenolic compound, and the wet material is obtained after the wet grinding treatment is completed.

[0030] The method for performing wet grinding treatment includes wetting the cathode material to be extracted and the phenolic compound with a solvent, and then grinding them to obtain the wet material.

[0031] The solvent for wet grinding treatment is not required in the present application, and only the wetting of the to-be-extracted cathode material and the phenolic compound is needed, preferably, water can be selected as the solvent from the green and pollution-free perspective.

[0032] The grinding method is not particularly limited in the present application, and at least one of manual grinding and mechanical ball milling can be used. Preferably, mechanical ball milling can be selected.

[0033] Further, the specific equipment for wet grinding treatment is not particularly limited in the present application, for example, a ball mill can be selected.

[0034] In step 2), the obtained wet material is subjected to calcination treatment under a protective atmosphere, and the to-be-extracted cathode material and the phenolic compound are subjected to solid-solid reaction, and after the calcination is completed, the calcined material is taken out after the furnace temperature is cooled to room temperature.

[0035] In the presence of the phenolic compound, lithium of the to-be-extracted cathode material is preferentially removed to form a soluble lithium salt in the process of calcination treatment. Specifically, the temperature of the calcination treatment is not less than 300 DEG C.

[0036] The specific equipment for calcination treatment is not particularly limited in the present application, and one of a muffle furnace, a tube furnace, a crucible furnace, etc. can be used.

[0037] In step 3), the calcined material obtained in step 2) is mixed with water to obtain a mixed system, and the soluble components in the calcined material in the aqueous solution can be leached, and after solid-liquid separation, a lithium-rich leaching solution is obtained.

[0038] In the present application, the mixing method of the above-mentioned calcined material and water is not limited, and the above-mentioned calcined material can be added to water for mixing, or water can be added to the above-mentioned calcined material for mixing.

[0039] The method for extracting lithium from waste lithium ion batteries in the present application does not particularly limit the method for solid-liquid separation, and filtration can be used for separation.

[0040] The method for extracting lithium from waste lithium ion batteries in the present application can selectively leach lithium by selecting a phenolic compound as a lithium extraction agent, reduce the extraction selectivity of other metal impurity ions, improve the lithium extraction efficiency, and does not introduce other volatile impurity ions in the process of lithium extraction, and does not produce waste gas pollution, which is environmentally friendly.

[0041] In the present application, the phenolic compound can be selected from at least one of phenol, hydroquinone and phloroglucinol, and when the phenolic compound is two or more of the above-mentioned compounds, the mass ratio of each compound is not limited in the present application. In a specific embodiment, preferably, phenol can be selected.

[0042] In a specific embodiment, when the positive electrode material to be extracted and the phenolic compound are mixed for wet grinding treatment, the mass ratio of the positive electrode material to be extracted and the phenolic compound is 1:(0.9-1.3), and further preferably 1:1.1.

[0043] In a specific embodiment, when wet grinding treatment is performed, water can be used to wet the positive electrode material to be extracted and the phenolic compound, and the mass ratio of the mixture of the positive electrode material to be extracted and the phenolic compound to water is 1:0.8-1:1.2, the wet grinding speed is 150 r / min-300 r / min, and the time is 20 min-60 min. By controlling the speed and time of wet grinding, the mixture of the positive electrode material to be extracted and the phenolic compound can be mixed uniformly and sufficiently, and the purity of the subsequent lithium extraction process can be improved.

[0044] In a specific embodiment, the heating rate of the calcination treatment is 5℃ / min-10℃ / min, the temperature is 300℃-500℃, and the time is 30 min-90 min. By adjusting the heating rate, temperature, and time of the calcination treatment, the lithium extraction efficiency can be improved, and the phenolic compound can be completely converted into carbon under these conditions, which can be separated from lithium through subsequent processes, thereby improving the lithium extraction purity.

[0045] In a specific embodiment, the calcined material is mixed with water to obtain a mixed system, and the mass-volume ratio of the calcined material to water in the mixed system is (80-160) g:1 L. When the mass-volume ratio of the calcined material to water is less than 80 g:1 L, the lithium extraction efficiency is low, and when the mass-volume ratio of the calcined material to water is higher than 160 g:1 L, water is wasted and the leaching rate of other metal ions such as nickel, cobalt, and manganese increases. Further, the mass-volume ratio of the calcined material to water in the mixed system can be preferably 120 g:1 L, under which conditions the lithium extraction efficiency is the highest and water is not wasted.

[0046] Further, the mixed system is heated in a water bath until the temperature of the mixed system is 30℃-70℃, and then the mixed system is stirred to obtain a lithium-rich leaching solution. The water bath heating can uniformly heat the mixed system, and the temperature is controllable. By controlling the temperature of the mixed system to be 30℃-70℃, the lithium element leaching can be accelerated, and the lithium extraction efficiency can be improved.

[0047] In a specific embodiment, the stirring speed is adjusted to 100 r / min-300 r / min, and the time is 30 min-70 min. When the stirring speed and time are within the above range, the soluble components in the calcined material can be fully dissolved in water, thereby facilitating the improvement of the lithium extraction efficiency.

[0048] The positive electrode material to be extracted is not particularly limited in the present application, for example, LiCoO2, Li2MnO4, LiNi x Coy Mn z O2, x+y+z=1. In one embodiment, LiNi 0.8 Co 0.1 Mn z O 0.1 .

[0049] In addition, the lithium-rich leaching solution obtained by the method of the present application can be used to prepare lithium-containing compounds, and the specific steps are as follows: after the lithium-rich leaching solution is concentrated, the concentrated system is mixed with a precipitant solution to obtain a lithium-containing compound.

[0050] The method of concentration is not particularly limited in the present application, and one of reduced pressure, heating, gel absorption, etc. can be selected. In one embodiment, heating is preferably selected.

[0051] The type of precipitant is not particularly limited in the present application, and only needs to react with lithium ions to form a lithium-containing compound. In one embodiment, a saturated sodium carbonate solution can be selected to obtain a lithium carbonate salt.

[0052] The present application will be further described in detail below through specific embodiments.

[0053] Example 1

[0054] The method for extracting lithium from waste lithium ion batteries in this embodiment includes the following steps:

[0055] 1) 100g LiNi 0.8 Co 0.1 Mn z O 0.1 The powder and 90g of phenol are mixed, and then added to a ball mill, and 155mL of water is added for wet grinding treatment to obtain a wet material, wherein the rotation speed of the wet grinding treatment is 150r / min, and the time is 20min.

[0056] 2) The wet material is placed in a muffle furnace, and heated from room temperature to 350℃ at a heating rate of 5℃ / min, and then baked for 40min. After the baking is completed, the furnace temperature is cooled to room temperature to obtain a baked material.

[0057] 3) The mixture of 80g of the baked material and 1L of water is heated in a water bath, and after the temperature reaches 40℃, the mixture is stirred, and then separated by filtration to obtain a lithium-rich leaching solution, wherein the stirring rate is 100r / min, and the leaching time is 40min.

[0058] 4) The lithium-rich leaching solution is heated to 100℃ for concentration, and a saturated sodium carbonate solution is added at 85℃ to recover lithium carbonate products, which are separated and washed to obtain high-purity lithium carbonate.

[0059] Example 2

[0060] The method for extracting lithium from waste lithium ion batteries in this embodiment comprises the following steps:

[0061] 1) 100 g of LiNi 0.8 Co 0.1 Mn 0.1 O2 powder and 100 g of phenol are mixed, and then added into a ball mill, 160 mL of water is added for wet grinding treatment, and a wet material is obtained, wherein the rotation speed of the wet grinding treatment is 150 r / min, and the time is 30 min.

[0062] 2) The wet material is placed in a muffle furnace, and the temperature is increased from room temperature to 400°C at a rate of 8°C / min, and then roasted for 40 min, and after the roasting is completed, the furnace temperature is cooled to room temperature to obtain a roasted material.

[0063] 3) The mixture of 100 g of the roasted material and 1 L of water is heated in a water bath, and after the temperature reaches 40°C, the mixture is stirred, and after filtration and separation, a lithium-rich leaching solution is obtained, wherein the stirring rate is 150 r / min, and the leaching time is 40 min.

[0064] 4) The lithium-rich leaching solution is heated to 100°C for concentration, and saturated sodium carbonate solution is added at 85°C to recover lithium carbonate products, and high-purity lithium carbonate is obtained after separation and water washing.

[0065] Example 3

[0066] The method for extracting lithium from waste lithium ion batteries in this embodiment comprises the following steps:

[0067] 1) 100 g of LiNi 0.8 Co 0.1 Mn 0.1 O2 powder and 110 g of phenol are mixed, and then added into a ball mill, 190 mL of water is added for wet grinding treatment, and a wet material is obtained, wherein the rotation speed of the wet grinding treatment is 200 r / min, and the time is 30 min.

[0068] 2) The wet material is placed in a muffle furnace, and the temperature is increased from room temperature to 400°C at a rate of 10°C / min, and then roasted for 40 min, and after the roasting is completed, the furnace temperature is cooled to room temperature to obtain a roasted material.

[0069] 3) The mixture of 100 g of the roasted material and 1 L of water is heated in a water bath, and after the temperature reaches 50°C, the mixture is stirred, and after filtration and separation, a lithium-rich leaching solution is obtained, wherein the stirring rate is 200 r / min, and the leaching time is 40 min.

[0070] 4) The lithium-rich leaching solution is heated to 100°C for concentration, and saturated sodium carbonate solution is added at 85°C to recover lithium carbonate product, and high-purity lithium carbonate is obtained by separation and water washing.

[0071] Example 4

[0072] The method for extracting lithium from waste lithium ion batteries in this example includes the following steps:

[0073] 1) 100 g of LiNi x Co y Mn z O2 powder and 110 g of phenol are mixed, and then added to a ball mill, and 210 mL of water is added for wet grinding treatment to obtain a wet material, wherein the rotation speed of the wet grinding treatment is 200 r / min, and the time is 30 min.

[0074] 2) The wet material is placed in a muffle furnace, and the temperature is increased from room temperature to 450°C at a rate of 5°C / min, and then calcined for 50 min, and after the calcination is completed, the furnace temperature is allowed to cool to room temperature to obtain a calcined material.

[0075] 3) The mixture of 120 g of the calcined material and 1 L of water is heated in a water bath, and after the temperature reaches 50°C, the mixture is stirred, and after separation by filtration, a lithium-rich leaching solution is obtained, wherein the stirring rate is 200 r / min, and the leaching time is 50 min.

[0076] 4) The lithium-rich leaching solution is heated to 100°C for concentration, and saturated sodium carbonate solution is added at 85°C to recover lithium carbonate product, and high-purity lithium carbonate is obtained by separation and water washing.

[0077] Example 5

[0078] The method for extracting lithium from waste lithium ion batteries in this example includes the following steps:

[0079] 1) 100 g of LiNi 0.8 Co 0.1 Mn 0.1 O2 powder and 110 g of phenol are mixed, and then added to a ball mill, and 210 mL of water is added for wet grinding treatment to obtain a wet material, wherein the rotation speed of the wet grinding treatment is 200 r / min, and the time is 30 min.

[0080] 2) The wet material is placed in a muffle furnace, and the temperature is increased from room temperature to 450°C at a rate of 5°C / min, and then calcined for 60 min, and after the calcination is completed, the furnace temperature is allowed to cool to room temperature to obtain a calcined material.

[0081] 3) The mixture of 120 g of the calcined material and 1 L of water is heated in a water bath, and after the temperature reaches 60°C, the mixture is stirred, and after filtration and separation, a lithium-rich leaching solution is obtained, wherein the stirring rate is 200 r / min, and the leaching time is 40 min.

[0082] 4) The lithium-rich leaching solution is heated to 100°C for concentration, and saturated sodium carbonate solution is added at 85°C to recover lithium carbonate products, and high-purity lithium carbonate is obtained after separation and water washing.

[0083] Example 6

[0084] The method for extracting lithium from waste lithium ion batteries in this example includes the following steps:

[0085] 1) 100 g of LiNi 0.8 Co 0.1 Mn 0.1 O2 powder and 110 g of phenol are mixed, and then added to a ball mill, and 210 mL of water is added for wet grinding treatment to obtain a wet material, wherein the rotation speed of the wet grinding treatment is 250 r / min, and the time is 40 min.

[0086] 2) The wet material is placed in a muffle furnace, and heated from room temperature to 450°C at a heating rate of 5°C / min for 60 min, and after the calcination is completed, the furnace temperature is allowed to cool to room temperature to obtain a calcined material.

[0087] 3) The mixture of 120 g of the calcined material and 1 L of water is heated in a water bath, and after the temperature reaches 60°C, the mixture is stirred, and after filtration and separation, a lithium-rich leaching solution is obtained, wherein the stirring rate is 250 r / min, and the leaching time is 50 min.

[0088] 4) The lithium-rich leaching solution is heated to 100°C for concentration, and saturated sodium carbonate solution is added at 85°C to recover lithium carbonate products, and high-purity lithium carbonate is obtained after separation and water washing.

[0089] Example 7

[0090] The method for extracting lithium from waste lithium ion batteries in this example includes the following steps:

[0091] 1) 100 g of LiNi 0.8 Co 0.1 Mn 0.1 O2 powder and 130 g of phenol are mixed, and then added to a ball mill, and 270 mL of water is added for wet grinding treatment to obtain a wet material, wherein the rotation speed of the wet grinding treatment is 300 r / min, and the time is 60 min.

[0092] 2) Put the wet material into a muffle furnace, and raise the temperature from room temperature to 500℃ at a rate of 5℃ / min, and bake for 70min. After the baking is completed, wait for the furnace temperature to cool to room temperature to obtain the baked material.

[0093] 3) Heat the mixture of 140g baked material and 1L water in a water bath, and after the temperature reaches 60℃, stir the mixture, and after filtration and separation, obtain the lithium-rich leaching solution, wherein the stirring rate is 250r / min, and the leaching time is 60min.

[0094] 4) Concentrate the above lithium-rich leaching solution by heating to 100℃, and at 85℃, add saturated sodium carbonate solution to recover lithium carbonate product, and separate and wash with water to obtain high-purity lithium carbonate.

[0095] Example 8

[0096] The method for extracting lithium from waste lithium ion positive electrode material in this example is basically the same as that in Example 5, except that hydroquinone is used instead of phenol.

[0097] Example 9

[0098] The method for extracting lithium from waste lithium ion positive electrode material in this example is basically the same as that in Example 5, except that phloroglucinol is used instead of phenol.

[0099] Example 10

[0100] The method for extracting lithium from waste lithium ion positive electrode material in this example is basically the same as that in Example 5, except that the mass of phenol is reduced from 110g to 70g.

[0101] Example 11

[0102] The method for extracting lithium from waste lithium ion positive electrode material in this example is basically the same as that in Example 5, except that the mass of phenol is increased from 110g to 150g.

[0103] Example 12

[0104] The method for extracting lithium from waste lithium ion positive electrode material in this example is basically the same as that in Example 5, except that the temperature raising rate in step 2) is adjusted to 15℃ / min.

[0105] Example 13

[0106] The method for extracting lithium from waste lithium ion positive electrode material in this example is basically the same as that in Example 5, except that the baking temperature in step 2) is adjusted to 600℃.

[0107] Example 14

[0108] The method for extracting lithium from waste lithium ion positive electrode material in this example is basically the same as that in Example 5, except that the roasting amount in step 3) is increased from 120 g to 180 g.

[0109] Example 15

[0110] The method for extracting lithium from waste lithium ion positive electrode material in this example is basically the same as that in Example 5, except that the water bath heating in step 4) is replaced by air bath heating.

[0111] Example 16

[0112] The method for extracting lithium from waste lithium ion positive electrode material in this example is basically the same as that in Example 5, except that LiCoO2 is used instead of LiNi 0.8 Co 0.1 Mn 0.1 O 2。

[0113] Example 17

[0114] The method for extracting lithium from waste lithium ion positive electrode material in this example is basically the same as that in Example 5, except that Li2MnO4 is used instead of LiNi 0.8 Co 0.1 Mn 0.1 O2.

[0115] Comparative Example 1

[0116] The method for extracting lithium from waste lithium ion positive electrode material in this example is basically the same as that in Example 5, except that sodium bisulfate is used instead of phenol.

[0117] Comparative Example 2

[0118] The method for extracting lithium from waste lithium ion positive electrode material in this example is basically the same as that in Example 5, except that carbon powder is used instead of phenol.

[0119] Comparative Example 3

[0120] The method for extracting lithium from waste lithium ion positive electrode material in this example is basically the same as that in Example 5, except that the roasting temperature in step 2) is adjusted to 200°C.

[0121] Test Example

[0122] 1. The leaching rates of lithium, nickel, cobalt, manganese and other metal elements in the lithium-rich leaching solution obtained in the above examples and comparative examples were detected, and the leaching rate formula was calculated by the following formula, and the results are shown in Table 1:

[0123]

[0124] E iC is the leaching rate of the metal element to be detected, and i C is the content of the metal element to be detected in the lithium-rich leaching solution, which is measured by an inductively coupled plasma optical emission spectrometer (ICP-OES), V i C is the volume of the lithium-rich leaching solution, M is the mass of the positive electrode material to be extracted before roasting, and W i C is the content of the metal element in the positive electrode material to be extracted, which is detected by ICP-OES.

[0125] Table 1

[0126]

[0127]

[0128] As can be seen from Table 1, compared with the comparative examples, the present application uses a phenolic compound as a lithium extraction agent, and the roasting temperature is not lower than 300°C, which has a higher extraction efficiency of lithium in the waste lithium-ion battery, and the lithium ion extraction rate is not less than 83%, even more than 99% or more. In addition, the entire process does not involve the introduction of other impurity ions, and will not produce waste gas pollution, and is environmentally friendly.

[0129] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for extracting lithium from spent lithium-ion batteries, characterized in that, The method comprises the following steps: 1) mixing the positive electrode material to be extracted and phenolic compounds, and then performing wet grinding treatment to obtain wet material; 2) performing roasting treatment on the wet material to obtain roasted material; 3) mixing the roasted material with water to obtain a lithium-rich leaching solution; In step 2), the roasting treatment is performed at a temperature not lower than 300 DEG C; in the presence of the phenolic compounds, lithium in the positive electrode material to be extracted is preferentially removed in the roasting treatment to form a soluble lithium salt; The mass ratio of the positive electrode material to be extracted to the phenolic compounds is 1:(0.9-1.3); In the wet grinding treatment, water is used as the solvent, and the mass ratio of the mixture of the positive electrode material to be extracted and the phenolic compounds to water is 1:0.8-1:1.2; The phenolic compounds include at least one of phenol, hydroquinone and phloroglucinol.

2. The method of claim 1, wherein, The roasting is performed at a temperature of 300 DEG C-500 DEG C and a heating rate of 5 DEG C / min-10 DEG C / min, and the roasting time is 30 min-90 min.

3. The method according to any of claims 1-2, characterized in that, The wet grinding treatment is performed at a rotating speed of 150 r / min-300 r / min for 20 min-60 min.

4. The method of claim 1, wherein, The mass-volume ratio of the roasted material to water is (80-160) g:1 L.

5. The method according to any of claims 1-2 or 4, characterized in that, Step 3) comprises: performing water bath heating on the mixed system until the temperature of the mixed system is 30 DEG C-70 DEG C, and then performing stirring on the mixed system to obtain the lithium-rich leaching solution.

6. The method of claim 5, wherein, The stirring is performed at a rotating speed of 100 r / min-300 r / min for 30 min-70 min.

7. The method of claim 1, wherein, The to-be-extracted cathode material is at least one of LiCoO2, Li2MnO4, LiNi x Co y Mn z O2, x+y+z=1.

8. The method of claim 1, wherein, Step 4) is further included: after performing concentration treatment on the lithium-rich leaching solution, mixing the concentrated system with a precipitant solution to obtain a lithium-containing compound.

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