A method for separating positive and negative electrode materials of waste lithium batteries

Abstract

The present application relates to a method for separating positive and negative electrode materials of waste lithium batteries, belonging to the technical field of lithium battery recycling; the method comprises: roasting the positive and negative electrode materials to be recycled so as to granulate the positive and negative electrode materials and thermally decompose part of organic matter to obtain a roasted mixture; powdering the roasted mixture to obtain a mixed powder; consuming the remaining organic matter in the mixed powder by microorganisms in a solution to obtain a slurry; flotation separation of the slurry to obtain a first negative electrode material and a flotation tailing; magnetic separation of the flotation tailing to obtain a positive electrode material and a second negative electrode material; the method combines physical separation with biological separation, has no secondary pollution, and the biological culture process is a process of consuming the surface binder of the positive electrode material, which reduces the adsorption of the positive electrode material on the graphite of the negative electrode material, thereby improving the recovery rate of the positive electrode material, that is, the recovery rate of the graphite of the negative electrode material.

Description

Technical Field

[0001] The present application relates to the technical field of lithium battery recycling, and in particular to a method for separating positive and negative electrode materials of waste lithium batteries. Background Art

[0002] After lithium-ion batteries were developed, they were first commercially used in digital electronic devices. With the energy crisis and environmental pollution problems such as urban smog, people realize that they must reduce or even stop using fuel vehicles, so lithium-ion batteries are used as the power source of vehicles. In recent years, lithium-ion new energy vehicles have been widely used and developed, and the number of new energy vehicles used in China is increasing. However, the problem that cannot be ignored is that after a certain number of charge and discharge cycles, the capacity of lithium-ion batteries will gradually lose until it does not meet the vehicle's use requirements. This is accompanied by the problem of recycling and reuse of battery materials.

[0003] In the prior art, the recycling of waste lithium-ion batteries requires disassembly, discharge, crushing, screening, magnetic separation and other pretreatments to obtain plastic shells, diaphragms, copper foils, aluminum foils and positive and negative electrode mixed materials, wherein the positive and negative electrode mixed materials are mainly positive electrode materials, negative electrode materials and binders, wherein the positive electrode materials are mainly Li, Ni, Co, and the negative electrode materials are mainly graphite. The binder for the positive electrode material generally uses oily organic matter such as PVDF (polyvinylidene fluoride), and the negative electrode generally uses water-soluble organic matter SBR (styrene-butadiene rubber), CMC (sodium carboxymethyl cellulose), etc. For the recycling of positive and negative electrode materials, the positive and negative electrode materials are generally recycled and reused separately at present, mainly because the binder in the negative electrode material is water-soluble. As long as it is washed with high-temperature water, the binder will dissolve in water, thereby separating the graphite of the negative electrode material. If the positive and negative electrode materials are recycled and reused together, during the processing, because the positive electrode materials contain a large amount of oily binders, it is not easy to separate from the positive electrode materials, making the surface of the positive electrode materials highly adsorbable, and graphite is very easy to adhere to the surface of the positive electrode materials, making it difficult to separate the positive and negative electrode materials. In addition, at present, organic acids or inorganic acids are generally used to leach metal ions in the positive electrode materials for separation of positive electrode materials to obtain salt solutions containing relevant metal ions. The acid leaching and salting out method can use inorganic acids and organic acids. In the process, the aluminum current collectors attached to the positive and negative electrode materials are easily dissolved, resulting in low recovery efficiency of Li, Ni, and Co, and easy to cause secondary pollution.

[0004] In order to avoid secondary pollution, someone proposed a flotation separation scheme for the positive and negative electrode materials of waste lithium batteries, which includes the following steps:

[0005] (1) mixing the positive and negative electrode materials of waste lithium batteries with water, and stirring and slurrying to obtain a mixed slurry; (2) adding a collector to the mixed slurry obtained in step (1) and stirring and slurrying; (3) placing the slurry after stirring and slurrying in step (2) in a flotation machine, adding a pH adjuster to adjust the pH of the slurry, adding a dispersant, adding a frother and flotation separation to obtain lithium-containing positive electrode powder and negative electrode stone; the negative electrode stone obtained by this method contains a large amount of metal particles, and the valuable cobalt and nickel in the lithium positive electrode powder cannot be directly separated, resulting in the inability to recover the valuable cobalt and nickel in the waste lithium batteries; someone has proposed another recycling method, which includes the following steps: step 1, high temperature treatment, placing the positive electrode sheet to be recycled in a heating furnace, and successively undergoing 300 to 40 After two high-temperature treatments at 0°C and 500-600°C, the active material automatically falls off to form powder, which is cooled and set aside; step two, removing the conductive carbon, collecting the powder that automatically falls off after the treatment in step one, sieving the powder and loading it into a container, then placing the container in a heating furnace for secondary baking at 600-850°C to remove the conductive carbon in the powder, and then sieving to obtain qualified powder; step three, exhaust gas treatment and waste utilization, passing the exhaust gas generated in steps one and two into a fixed bed for harmless treatment, and recovering the current collector generated in step one. This scheme only recovers the powder in the positive electrode. Since the positive electrode material and the negative electrode material are mixed together during the recycling process of the waste lithium battery, the above method cannot achieve the recovery and utilization of valuable metals in the waste lithium battery. Summary of the invention

[0006] The present application provides a method for separating positive and negative electrode materials of waste lithium batteries to improve the recovery rate of positive and negative electrode materials while avoiding secondary pollution in the recovery process.

[0007] In a first aspect, the present application provides a method for separating positive and negative electrode materials of waste lithium batteries, the method comprising:

[0008] The positive and negative electrode materials to be recovered are roasted to granulate the positive and negative electrode materials and thermally decompose part of organic matter to obtain a roasted mixture;

[0009] Powdering the calcined mixture to obtain a mixed powder;

[0010] Using microorganisms in a solution to consume the remaining organic matter in the mixed powder to obtain a slurry;

[0011] flotation the slurry to obtain a first negative electrode material and flotation tailings;

[0012] The flotation tailings are subjected to magnetic separation to obtain positive electrode materials and second negative electrode materials.

[0013] As an optional implementation manner, the calcination temperature is 400-600°C.

[0014] As an optional implementation, the pulverization treatment method includes ball milling, and the grinding balls of the ball mill are made of non-metallic material.

[0015] As an optional embodiment, in the ball milling, the weight ratio of the calcined mixture to the grinding balls is 1:(0.01-0.05), the rotation speed of the ball milling is 300-1000 rpm, and the ball milling time is 20-40 hours.

[0016] As an optional implementation, in the process of consuming the remaining organic matter in the mixed powder by using microorganisms in the solution, the temperature of the entire consumption process is 30-35° C., and the consumption time is 60-100 hours.

[0017] As an optional embodiment, the microorganisms include EM ecological bacteria.

[0018] As an optional embodiment, the process of consuming the remaining organic matter in the mixed powder by using microorganisms in the solution includes:

[0019] Microorganisms, mixed powder, compound amino acids and sucrose are mixed in a first solvent to consume the remaining organic matter in the mixed powder; the mass ratio of the solvent, mixed powder, microorganisms, compound amino acids and sucrose is 1000:(300-500):(0.5-3):(3-5):(3-5).

[0020] As an optional embodiment, the flotation of the slurry includes:

[0021] The slurry is mixed with the second solvent, the adjusting agent, the depressant and the frother, and then flotation is performed;

[0022] The regulator includes sodium carbonate; the inhibitor includes sodium hexametaphosphate; and the foaming agent includes methyl isobutyl carbinol.

[0023] As an optional implementation manner, the volume usage of the second solvent is 5 to 10 times the volume of the slurry.

[0024] As an optional embodiment, in the flotation, the mass of the regulator used per ton of the positive and negative electrode materials to be recovered is 1000-1500g, the mass of the inhibitor used per ton of the positive and negative electrode materials to be recovered is 400-500g, and the mass of the foaming agent used per ton of the positive and negative electrode materials to be recovered is 20-30g; and / or

[0025] The aeration volume of the flotation is 0.1 to 0.25 m3 / (min·m 2 ).

[0026] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0027] The method provided in the embodiment of the present application combines physical separation with biological separation, has no secondary pollution, and the biological cultivation process therein is a process of consuming the binder on the surface of the positive electrode material, thereby reducing the adsorption effect of the positive electrode material on the negative electrode material graphite, thereby improving the recovery rate of the positive electrode material, that is, the recovery rate of the negative electrode material graphite. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0029] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0030] Figure 1 A flowchart of a method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0032] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0033] like Figure 1 As shown, the embodiment of the present application provides a method for separating positive and negative electrode materials of waste lithium batteries, the method comprising:

[0034] S1. The positive and negative electrode materials to be recovered are calcined to granulate the positive and negative electrode materials and thermally decompose part of the organic matter to obtain a calcined mixture;

[0035] In some embodiments, the calcination temperature is 400-600° C. Within this temperature range, thermal decomposition of the positive and negative electrode materials can be well achieved, and the positive and negative electrode materials can be granulated.

[0036] Specifically, in this embodiment, the recovered positive and negative electrode materials are calcined in a tubular carbonization furnace under nitrogen protection at T1 = 400-600° C., and after cooling to room temperature, a calcined mixture is obtained.

[0037] S2. The calcined mixture is powdered to obtain a mixed powder;

[0038] In some embodiments, the powdering treatment method can be selected from ball milling, and the grinding ball material of the ball mill is a non-metallic material. Specifically, the grinding ball can be selected from one of polytetrafluoroethylene balls or ceramic balls. Metal balls are not selected because the metal material in the calcined mixture and the metal ball are prevented from undergoing electron migration during high-energy ball milling, thereby changing the activity of the metal material. Furthermore, in the ball milling, the weight ratio of the calcined mixture to the grinding ball is 1: (0.01-0.05), the ball milling speed is 300-1000rpm, and the ball milling time is 20-40h. The various parameters of the ball milling process are controlled within the above range, and a mixed powder that meets the requirements can be prepared, and the mixed powder can provide convenient conditions for the consumption of organic matter by EM ecological bacteria in subsequent steps.

[0039] Specifically, in this embodiment, the calcined mixture is placed in a ball mill for high-energy ball milling treatment, and then sieved to obtain a ball-milled mixture; the weight ratio G1 of the calcined mixture to the grinding balls is 1:0.01-0.05, the ball milling speed V1 is 300-1000rpm, and the ball milling time is H1=20-40h.

[0040] S3. Using microorganisms to consume the remaining organic matter in the mixed powder in the solution to obtain a slurry;

[0041] In some embodiments, the use of microorganisms in the solution to consume the remaining organic matter in the mixed powder includes: mixing microorganisms, mixed powder, compound amino acids and sucrose in a first solvent to consume the remaining organic matter in the mixed powder; the process of microorganisms consuming organic matter is actually the process of cultivating microorganisms, and the mass ratio of the solvent, mixed powder, microorganisms, compound amino acids and sucrose is 1000: (300-500): (0.5-3): (3-5): (3-5). Among them, the microorganisms include EM ecological bacteria, the temperature of the entire consumption process is 30-35°C, and the consumption time is 60-100h. Controlling the above conditions can provide a better culture environment for microorganisms, thereby achieving better consumption of organic matter.

[0042] Specifically, in this embodiment, the ball-milled mixture is placed in a high-temperature stirring kettle, water is added and stirred to mix, and the temperature is controlled at T2 = 30-35°C, preferably 32°C, EM ecological bacteria, complex amino acids, and sucrose are added, and H2 = 60-100h is maintained to obtain a slurry; wherein, the amount ratio G2 of water, ball-milled mixture, 1 part of EM ecological bacteria, 5 parts of complex amino acids, and sucrose is 1000:(300-500):(0.5-3):(3-5):(3-5).

[0043] S4. flotation the slurry to obtain a first negative electrode material and flotation tailings;

[0044] In some embodiments, the flotation of the slurry includes: mixing the slurry with a second solvent, a regulator, an inhibitor, and a frother, and then flotation; wherein the regulator includes sodium carbonate; the inhibitor includes sodium hexametaphosphate, and the frother includes methyl isobutyl carbinol. Furthermore, the volume of the second solvent is 5 to 10 times the volume of the slurry; in the flotation, the mass of the regulator used per ton of the positive and negative electrode materials to be recovered is 1000 to 1500 g, the mass of the inhibitor used per ton of the positive and negative electrode materials to be recovered is 400 to 500 g, and the mass of the frother used per ton of the positive and negative electrode materials to be recovered is 20 to 30 g; the air volume of the flotation is 0.1 to 0.25 m 3 / (min·m 2 ).

[0045] Specifically, in this embodiment, water 5-10 times (preferably 8 times) the volume of the slurry is added to the stirring kettle, and then the adjusting agent, inhibitor and foaming agent are added. After stirring evenly, the slurry in the stirring kettle is drawn out and floated in a flotation column to obtain flotation foam and flotation tailings; wherein the adjusting agent is sodium carbonate, and the amount is 1000-1500g per ton of positive and negative electrode materials, preferably 1300g; the inhibitor is sodium hexametaphosphate, and the amount is 400-500g per ton of positive and negative electrode materials, preferably 450g; the foaming agent is methyl isobutyl carbinol, and the amount is 20-30g per ton of waste ternary lithium battery positive and negative electrode materials, preferably 25g; the air filling volume of the flotation column flotation is 0.10-0.25m 3 / (min·m 2 ), preferably 0.2m 3 / (min·m 2 ).

[0046] S5. Perform magnetic separation on the flotation tailings to obtain positive electrode material and a second negative electrode material.

[0047] Specifically, in this embodiment, the flotation tailings are magnetically separated using a high gradient magnetic separator (the background field strength of the magnetic separator is adjusted to 0.6 T and the pulse size is 200 times / min) to obtain magnetic products and non-magnetic products; the magnetic product is then filtered to obtain the positive electrode powder of the ternary lithium battery; the non-magnetic product is combined with the flotation foam and filtered to obtain the negative electrode powder.

[0048] The method combines physical separation with biological separation, has no secondary pollution, and the biological culture process is a process of consuming the surface binder of the positive electrode material, which reduces the adsorption effect of the positive electrode material on the negative electrode material graphite, and improves the recovery rate of the positive electrode material and the recovery rate of the negative electrode material graphite. The positive electrode powder obtained by the method contains 5.41% of Li, 15.21% of Ni, 7.92% of Co, and 0.51% of graphite. The positive electrode powder has a Li recovery rate of 96.38%, a Ni recovery rate of 96.97%, and a Co recovery rate of 97.04%. The graphite grade of the obtained negative electrode material graphite is 92.31%, and the graphite recovery rate is 98.96%.

[0049] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0050] Examples 1-9

[0051] A method for separating positive and negative electrode materials of waste lithium batteries, the method comprising:

[0052] (1) calcining the recovered positive and negative electrode materials in a tubular carbonization furnace under nitrogen protection at a temperature of T1, and cooling to room temperature to obtain a calcined mixture;

[0053] (2) placing the calcined mixture into a ball mill for high-energy ball milling, and sieving after ball milling to obtain a ball-milled mixture; the weight ratio of the calcined mixture to the grinding balls is G1, the speed of the ball mill is V1, and the ball milling time is H1;

[0054] (3) placing the ball-milled mixture into a high-temperature stirring kettle, adding water and stirring to mix, and controlling the temperature at T2, adding EM ecological bacteria, compound amino acids, and sucrose, and maintaining the temperature for H2 to obtain a slurry, wherein the amount ratio of water, ball-milled mixture, EM ecological bacteria, compound amino acids, and sucrose is G2;

[0055] (4) Add 8 times the volume of water of the slurry to the stirring tank of step (3), then add the adjusting agent, the inhibitor and the foaming agent, stir evenly, draw out the slurry in the stirring tank, and flotate in a flotation column to obtain flotation foam and flotation tailings; wherein the adjusting agent is sodium carbonate, and the amount is 1300g per ton of positive and negative electrode materials; the inhibitor is sodium hexametaphosphate, and the amount is 450g per ton of positive and negative electrode materials; the foaming agent is methyl isobutyl carbinol, and the amount is 25g per ton of waste ternary lithium battery positive and negative electrode materials; the aeration volume of the flotation column flotation is 0.2m 3 / (min·m 2 );

[0056] (5) Using a high gradient magnetic separator (adjusting the background field strength of the magnetic separator to 0.6 T and the pulse size to 200 times / min), the flotation tailings in step (4) are magnetically separated to obtain a magnetic product and a non-magnetic product; then, the magnetic product is filtered to obtain a positive electrode powder for a ternary lithium battery; the non-magnetic product is combined with the flotation foam in step (4) and filtered to obtain a negative electrode powder.

[0057] The main parameter control of each embodiment is shown in the following table:

[0058] T1 G1 V1 H1 T2 H2 G2 Example 1 500 1:0.03 800 30 32 78 1000:400:1:5:5 Example 2 400 1:0.03 1000 20 30 60 1000:300:0.5:3:3 Example 3 600 1:0.05 500 40 35 60 1000:500:3:5:5 Example 4 500 1:0.01 300 30 32 60 1000:400:1:5:5 Example 5 500 1:0.03 800 30 32 60 1000:400:1:5:5 Example 6 500 1:0.03 800 30 32 70 1000:400:1:5:5 Example 7 500 1:0.03 800 30 32 80 1000:400:1:5:5 Example 8 500 1:0.03 800 30 32 90 1000:400:1:5:5 Example 9 500 1:0.03 800 30 32 100 1000:400:1:5:5

[0059] The recovery conditions of the methods provided in each embodiment are shown in the following table:

[0060] Li recovery rate Ni recovery Co recovery rate Graphite recovery rate Example 1 96.38 96.97 97.04 98.96 Example 2 94.27 95.02 95.32 93.38 Example 3 95.57 95.32 95.71 94.96 Example 4 93.62 94.19 93.46 94.21 Example 5 95.12 95.34 94.76 94.96 Example 6 96.01 95.93 96.79 98.32 Example 7 96.24 96.54 97.36 98.63 Example 8 96.21 96.61 97.32 98.78 Example 9 96.26 96.63 97.29 98.69

[0061] It can be seen from the above table that the positive and negative electrode materials are recycled by the method provided in the embodiment of the present application, and both the positive electrode material and the negative electrode material graphite have a good recovery rate. The positive electrode powder obtained by this method contains Li 5.41%, Ni 15.21%, Co 7.92%, and a graphite content of 0.51%. The Li recovery rate of the positive electrode powder can reach 96.38%, the Ni recovery rate can reach 96.97%, and the Co recovery rate can reach 97.04%; the graphite grade of the obtained negative electrode material graphite is 92.31%, and the graphite recovery rate can reach 98.96%. Through the single factor investigation of the cultivation time of EM ecological bacteria through Examples 1 and Examples 5-9, it was found that with the extension of the cultivation time, the recovery rates of the positive and negative electrodes both showed an upward trend, until the cultivation time was 78 hours, the recovery rates of the positive and negative electrodes reached a better value, and as time continued to extend, the recovery rates of the positive and negative electrodes did not increase significantly. The possible reason is that when the cultivation time of the EM ecological bacteria is 78 hours, its decomposition is more complete and decomposed into more biological enzymes. The biological enzymes have a good consumption effect on the organic matter on the surface of the mixture after ball milling, so as to reduce the adsorption of the positive electrode material on the negative electrode material graphite, thereby improving the recovery rate of the positive electrode material, that is, the recovery rate of the negative electrode material graphite.

[0062] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0063] In this application, unless otherwise specified, directional words such as "upper" and "lower" used refer specifically to the directions of the drawings in the accompanying drawings. In addition, in the description of the specification of this application, the terms "include", "comprise", etc. mean "including but not limited to".

[0064] In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B, which can represent: A exists alone, A and B exist at the same time, and B exists alone. Wherein A, B can be singular or plural. In this article, "at least one" refers to one or more, and "multiple" refers to two or more. "At least one", "the following at least one (individual)" or similar expressions refer to any combination of these items, including any combination of single (individual) or plural (individual). For example, "at least one (individual) of a, b, or c", or "at least one (individual) of a, b, and c", can all represent: a, b, c, ab (i.e. a and b), ac, bc, or abc, wherein a, b, c can be single or multiple respectively.

[0065] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for separating positive and negative electrode materials of waste lithium batteries, characterized in that: The method comprises: The positive and negative electrode materials to be recovered are roasted to granulate the positive and negative electrode materials and thermally decompose part of organic matter to obtain a roasted mixture; Powdering the calcined mixture to obtain a mixed powder; Using microorganisms in a solution to consume the remaining organic matter in the mixed powder to obtain a slurry; flotation the slurry to obtain a first negative electrode material and flotation tailings; Performing magnetic separation on the flotation tailings to obtain a positive electrode material and a second negative electrode material; The powdering treatment method includes ball milling, in which the weight ratio of the calcined mixture to the grinding balls is 1:0.01-0.05, the rotation speed of the ball mill is 300-1000 rpm, and the ball milling time is 20-40 hours; In the process of consuming the remaining organic matter in the mixed powder by microorganisms in the solution, the temperature of the entire consumption process is 30 to 35° C., and the consumption time is 60 to 100 hours; The method of using microorganisms in the solution to consume the remaining organic matter in the mixed powder comprises: Mixing microorganisms, mixed powder, compound amino acids and sucrose in a first solvent to consume the remaining organic matter in the mixed powder; the mass ratio of the first solvent, mixed powder, microorganisms, compound amino acids and sucrose is 1000:300-500:0.5-3:3-5:3-5; The graphite content in the positive electrode material obtained by the separation method is 0.51%.

2. The method for separating positive and negative electrode materials of waste lithium batteries according to claim 1, characterized in that: The calcination temperature is 400-600°C.

3. The method for separating positive and negative electrode materials of waste lithium batteries according to claim 1, characterized in that: The grinding balls of the ball mill are made of non-metallic material.

4. The method for separating positive and negative electrode materials of waste lithium batteries according to claim 1, characterized in that: The microorganisms include EM ecological bacteria.

5. The method for separating positive and negative electrode materials of waste lithium batteries according to claim 1, characterized in that: The flotation of the slurry comprises: The slurry is mixed with the second solvent, the adjusting agent, the depressant and the frother, and then flotation is performed; The regulator includes sodium carbonate; the inhibitor includes sodium hexametaphosphate; and the foaming agent includes methyl isobutyl carbinol.

6. The method for separating positive and negative electrode materials of waste lithium batteries according to claim 5, characterized in that: The volume usage of the second solvent is 5 to 10 times the volume of the slurry.

7. The method for separating positive and negative electrode materials of waste lithium batteries according to claim 5, characterized in that: In the flotation, the mass of the regulator used per ton of the positive and negative electrode materials to be recovered is 1000-1500g, the mass of the inhibitor used per ton of the positive and negative electrode materials to be recovered is 400-500g, and the mass of the foaming agent used per ton of the positive and negative electrode materials to be recovered is 20-30g; and / or The aeration volume of the flotation is 0.1 to 0.25 m 3 / (min·m 2 ).

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