Method for separating spent battery current collector from active material

Abstract

The application belongs to the technical field of battery recycling, and particularly relates to a method for separating a current collector from active material of a waste battery. The method comprises the following steps: washing electrode material with water and then washing with a sulfate solution; the washing with the sulfate solution comprises adjusting the Zeta potential of the surface of an aluminum foil to be positive. The method for separating the current collector from the active material of the waste battery provided by the application uses the charge neutralization effect of sulfate radicals in the sulfate solution to directionally strip the oxide layer and synchronously generate soluble metal complexes to inhibit precipitation.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of battery recycling, and particularly relates to a method for separating a current collector and active material of a waste battery. BACKGROUND

[0002] Current waste battery recycling technologies mainly include physical method, wet method and fire method, which focus on the separation of current collector (aluminum foil / copper foil) and active material. Among them, the physical method separates components through crushing, screening, magnetic separation and other mechanical means. The wet method uses acid / alkali leaching to dissolve metals. The fire method removes organic matter through high-temperature incineration, which has extremely high energy consumption and releases toxic gases (such as hydrogen fluoride), and needs a complex tail gas treatment system.

[0003] However, the traditional physical method sorting has the problems of large crushing particle size, insufficient sorting precision, and lack of oxidation layer stripping mechanism, etc. Although the wet method has a high recovery rate (such as lithium > 90%), it generates a large amount of waste liquid (acid consumption > 2 mol / L), and the complex formed after the corrosion of aluminum foil (such as AlPO4) interferes with the subsequent separation, and the acid leaching system has poor selectivity. The fire method has high processing cost and low metal recovery rate. SUMMARY

[0004] To solve the above problems, the application provides a method for separating a current collector and active material of a waste battery to solve at least one of the above technical problems.

[0005] The application is achieved by the following technical solutions:

[0006] The application provides a method for separating a current collector and active material of a waste battery, which comprises the following steps:

[0007] The electrode material is washed with a sulfate solution after water washing treatment.

[0008] The sulfate solution washing includes adjusting the Zeta potential of the aluminum foil surface to a positive value.

[0009] In some possible implementation manners, the step of adjusting the Zeta potential of the aluminum foil surface includes:

[0010] The electrode material after water washing treatment is mixed and stirred with the sulfate solution for immersion washing.

[0011] In some possible implementation manners, the Zeta potential of the aluminum foil surface is adjusted to 7 mV-9 mV.

[0012] In some possible implementation manners, the pH value of the sulfate solution is 1-4.

[0013] In some possible implementation manners, the concentration of the sulfate in the sulfate solution is 8 g / L-12 g / L.

[0014] In some possible implementations, the sulfate salt solution comprises at least one of ferric sulfate, lithium sulfate, sodium sulfate, copper sulfate, and magnesium sulfate.

[0015] In some possible implementations, the sulfate salt solution further comprises hydrogen peroxide and an additive.

[0016] In some possible implementations, the temperature of the stirring and soaking is 50-60°C.

[0017] In some possible implementations, in the stirring and soaking, the solid-liquid volume ratio of the electrode material to the sulfate salt solution is 1:(2-5).

[0018] In some possible implementations, the mass fraction of the hydrogen peroxide is 1%-5%.

[0019] In some possible implementations, the mass fraction of the additive is 3%-13%.

[0020] In some possible implementations, the additive comprises at least one of sodium citrate, lithium citrate, sodium acetate, ferrous oxalate, ferrous phosphate, ferric phosphate, sodium carbonate, and sodium bicarbonate.

[0021] In some possible implementations, the water washing process comprises a first-stage water washing and a second-stage water washing.

[0022] In some possible implementations, the water washing process lasts for 60-90 minutes.

[0023] In some possible implementations, the water washing process is performed at a temperature of 40-50°C.

[0024] In some possible implementations, the solid-liquid volume ratio of the first-stage water washing is 1:(4-6).

[0025] In some possible implementations, the solid-liquid volume ratio of the second-stage water washing is 1:(2-3).

[0026] In some possible implementations, the time ratio of the first-stage water washing to the second-stage water washing is 1:(0.8-1).

[0027] In some possible implementations, the water washing process further comprises ultrasonic assistance.

[0028] In some possible implementations, the sulfate salt solution washing further comprises ultrasonic assistance.

[0029] In some possible implementations, the ultrasonic assistance has a frequency of 35-45 kHz.

[0030] In some possible implementation manners, the ultrasonic frequency of the ultrasonic-assisted treatment is 35 kHz to 45 kHz.

[0031] In some possible implementation manners, the particle size of the electrode material is 0.5 mm to 5 mm.

[0032] In some possible implementation manners, the preparation of the electrode material includes the following steps:

[0033] The electrode sheet is crushed to below 5 mm and sieved to obtain the electrode material.

[0034] In some possible implementation manners, in the sieving, the mesh number of the sieve is 20 mesh to 60 mesh.

[0035] In some possible implementation manners, the proportion of the sieve residue is > 85%.

[0036] In some possible implementation manners, the particle size of the electrode material is 3 mm to 5 mm.

[0037] Compared with the prior art, the method for separating the current collector and the active material of the waste battery provided by the application has at least the following beneficial technical effects:

[0038] The method for separating the current collector and the active material of the waste battery provided by the application uses the charge neutralization effect of sulfate (SO4 2- ) in the sulfate solution to directionally strip the oxide layer and synchronously generate soluble metal complexes to inhibit precipitation. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical scheme and advantages of the application clearer, the application is described and explained below in combination with embodiments. It should be understood that the specific embodiments described herein are only used to explain the application and do not limit the application. Based on the embodiments provided by the application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the application.

[0040] Obviously, the following description is only some examples or embodiments of the application, and for those of ordinary skill in the art, the application can also be applied to other similar scenarios without creative labor. In addition, it can be understood that although the efforts made in this development process can be complex and lengthy, for those of ordinary skill in the art related to the disclosed content of the application, some design, manufacture or production changes based on the technical content disclosed in the application are only routine technical means and should not be understood as insufficient disclosure of the application.

[0041] However, there are cases where unnecessary detailed description is omitted. For example, there are cases where detailed description of matters well known to those skilled in the art, repeated description of substantially the same structure are omitted. This is to avoid the following description unnecessarily becoming lengthy and to facilitate understanding by those skilled in the art. In addition, the following description is provided in order for those skilled in the art to fully understand the present application and is not intended to limit the subject matter recited in the claims.

[0042] If not specifically stated, all embodiments of the present application and optional embodiments can be combined to form new technical solutions, and all technical features of the present application and optional technical features can be combined to form new technical solutions.

[0043] Currently, the physical sorting technology has at least the following deficiencies: ① In the crushing link, the crushing particle size is usually > 10 mm, which causes the ductile aluminum foil to form sheet-shaped winding, and the residual amount of aluminum scraps in the black powder after screening is very high (generally 2%~1.5%); the physical method also needs to add a high-temperature roasting or alkali leaching aluminum removal process, which increases energy consumption (generally 30%) and produces aluminum-containing waste residue. ② Insufficient sorting precision, limitations of air flow sorting: although it can strip very fine powder (recovery rate about 96%~98%), but the particle size of the crushed copper foil / aluminum foil is uneven (generally in the range of 0.2mm~1mm), and the shell fragments are mixed in, which reduces the purity to below 95%. ③ Lack of oxidation layer stripping mechanism, inefficient water washing process: fixed solid-liquid ratio (1:3) and mechanical stirring can only remove the surface electrolyte, and cannot penetrate the dense oxidation layer (Al2O3) on the surface of the aluminum foil, resulting in the dissolution of aluminum ions as impurities during subsequent acid leaching.

[0044] In the chemical treatment technology, the wet acid leaching system has poor selectivity, and aluminum complexing interference will occur, high-concentration sulfuric acid (generally 2mol / L or more) will corrode the aluminum foil to generate Al 3+ , combine with PO4 3- to form insoluble AlPO4 precipitate, which requires multi-stage pH adjustment (lithium loss rate generally more than 10%). At the same time, the oxidation layer stripping relies on high-concentration acid / alkali, resulting in large reagent consumption and fluctuation of metal recovery purity (such as black powder purity can only reach below 98.5%); relying solely on high-concentration acid / alkali to forcibly strip leads to large reagent consumption, and a large amount of waste liquid pollution, greatly increasing the cost of treating wastewater.

[0045] In the pyroprocessing technology, high-temperature incineration (temperature generally needs to be above 1200℃) will release HF gas, which needs to be treated by "incinerator + three-stage alkali spraying", with very high investment cost. Low metal recovery rate: nickel and cobalt form alloy phases in the slag, reducing the recovery rate of metals.

[0046] In order to solve the above problems, the embodiment of the present application provides a method for separating the current collector and active material of waste batteries. The method proposes a technical route of "crushing-gradient washing-iron sulfate salt directional dissociation", solves the problems of incomplete separation of the current collector, low acid leaching efficiency and secondary pollution, and provides a full-process technical path with high economy and low pollution for the regeneration of waste lithium batteries. The following is a detailed scheme of a method for separating the current collector and active material of waste batteries.

[0047] The embodiment of the present application provides a method for separating the current collector and active material of waste batteries, which comprises the following steps:

[0048] S10. The electrode material is washed with a sulfate salt solution after water washing treatment.

[0049] The sulfate salt solution washing includes adjusting the Zeta potential of the aluminum foil surface to a positive value.

[0050] The method for separating the current collector and active material of waste batteries provided by the embodiment of the present application can remove electrolyte residues and loose oxide layer structure through water washing treatment; the sulfate salt solution washing utilizes the charge neutralization effect of sulfate ions (SO4 2- ) in the sulfate salt solution to directionally strip the oxide layer and synchronously generate soluble metal complexes to inhibit precipitation.

[0051] In the embodiment, when the sulfate salt solution is washed, for the electrode material containing copper foil and aluminum foil, SO4 2- The synergistic effect of electrostatic neutralization and Fe 3+ competitive complexation can improve the removal rate of aluminum / copper (>99.5%). For the electrode material containing aluminum foil, the oxide layer on the surface of the aluminum foil is protonated in the sulfate salt solution, and at the same time, aluminum generates soluble complex precipitates, the charge superposition effect adjusts the Zeta potential of the aluminum foil surface to a positive value, the electrostatic repulsion of the aluminum foil causes the oxide layer to collapse, and then the active material is stripped from the surface of the aluminum foil. The related chemical reaction formula is as follows:

[0052] Al2O3+ 6H+ → 2Al 3+ + 3H2O{Oxide layer protonation};

[0053] Al 3+ + SO4 2- → [Al(SO4)] + {Soluble complex inhibits precipitation}.

[0054] In some embodiments, in the above step S10, the particle size of the electrode material is less than 5mm. In this case, the extension space of the current collector can be reduced, and the risk of sheet winding can be reduced.

[0055] In some embodiments, in the above step S10, the particle size of the electrode material is 4mm-5mm.

[0056] In some embodiments, in the step S10, the preparation of the electrode material includes the following steps:

[0057] S101. crushing the electrode sheet to below 7mm and sieving to obtain the electrode material.

[0058] In some embodiments, in the step S101, the mesh size of the sieve is 20-60 mesh.

[0059] In some embodiments, in the step S101, the sieving includes the following steps:

[0060] S1011. sequentially passing the crushed electrode sheet through a 20 mesh sieve, a 40 mesh sieve and a 60 mesh sieve, and obtaining the sieve residue of the 40 mesh sieve and the 60 mesh sieve as the electrode material.

[0061] In the sieving, the sieve residue after the 20 mesh sieve is relatively large, and is mostly clean aluminum / copper foil without washing and recycling; the sieve residue after the 60 mesh sieve is too small, and is mostly black powder without washing and recycling, so these are not the electrode material that needs to be processed in the embodiments of the present application.

[0062] In some embodiments, in the step S1011, the total amount of the sieve residue of the 40 mesh sieve and the 60 mesh sieve accounts for ≥60%.

[0063] In some embodiments, in the step S1011, the total amount of the sieve residue of the 40 mesh sieve and the 60 mesh sieve accounts for >85%.

[0064] In some embodiments, in the step S10, the water washing treatment includes a first-stage water washing and a second-stage water washing. In this case, the first-stage water washing separates the black powder and separates part of the black powder on the metal foil (copper foil, aluminum foil); the second-stage water washing separates the black powder on the metal foil (copper foil, aluminum foil) from the metal foil.

[0065] In some embodiments, the solid-liquid volume ratio of the first-stage water washing is 1:(4-6).

[0066] In some embodiments, the solid-liquid volume ratio of the second-stage water washing is 1:(2-3).

[0067] In some embodiments, in the step S10, the water washing treatment is performed for 60-90 minutes.

[0068] In some embodiments, in the step S10, the water washing treatment is performed at a temperature of 40-50°C.

[0069] In some embodiments, in the step S10, the water washing process further comprises ultrasonic assistance. In this case, the cavitation effect of the ultrasonic generates micro-jet impact on the oxide layer (local pressure > 100 MPa), which can destroy the oxide layer of the aluminum foil / copper foil, promote the separation of the current collector and the active material, and greatly shorten the oxide layer peeling time from more than 40 min to less than 15 min.

[0070] In some embodiments, the frequency of the ultrasonic assistance is 35 kHz-45 kHz. In this case, the energy consumption caused by the ultrasonic assistance is reduced under the premise of ensuring the quality of the water washing.

[0071] In some embodiments, the time ratio of the first-stage water washing to the second-stage water washing is 1: (0.8-1).

[0072] In some embodiments, in the step S10, the water washing process comprises:

[0073] S102. The electrode material is subjected to first-stage water washing and second-stage water washing under ultrasonic assistance.

[0074] In some embodiments, in the step S10, the Zeta potential of the surface of the aluminum foil is adjusted to 7 mV-9 mV.

[0075] In some embodiments, in the step S10, the step of adjusting the Zeta potential of the surface of the aluminum foil to a positive value comprises:

[0076] S103. The electrode material after the water washing process is mixed with a sulfate solution and subjected to stirring and immersion washing.

[0077] In the step of adjusting the Zeta potential of the surface of the aluminum foil to a positive value, the metal ions in the sulfate specifically hydrolyze (weak base sulfate of sulfuric acid), adsorb and complex on the surface of the aluminum oxide layer, and these charge superposition effects change the surface Zeta potential.

[0078] In some embodiments, in the step S10, the pH value of the sulfate solution is 1-4.

[0079] In some embodiments, a phosphoric acid solution or a sulfuric acid solution is used to adjust the pH value of the sulfate solution.

[0080] In some embodiments, in the step S10, the concentration of the sulfate in the sulfate solution is 8 g / L-12 g / L.

[0081] In some embodiments, in the step S10, the sulfate comprises at least one of iron sulfate, lithium sulfate, sodium sulfate, copper sulfate, and magnesium sulfate.

[0082] In some embodiments, in step S10, the sulfate solution further comprises hydrogen peroxide and an additive. In this case, the hydrogen peroxide can passivate the aluminum in the electrode and promote the separation of the black powder and the aluminum foil; the additive is used to prevent the complex precipitation of copper.

[0083] In some embodiments, in step S10, the mass fraction of the hydrogen peroxide is 1% to 5%. In this case, the hydrogen peroxide can passivate the aluminum without causing the oxidation of the black powder, and an excess amount will cause the oxidation of the black powder.

[0084] In some embodiments, in step S10, the mass fraction of the additive is 3% to 13%. In this case, the sulfate solution washing rate is improved.

[0085] In some embodiments, the additive comprises at least one of sodium citrate, lithium citrate, sodium acetate, ferrous oxalate, ferrous phosphate, ferric phosphate, sodium carbonate, and sodium bicarbonate.

[0086] In some embodiments, in step S10, the temperature of the sulfate solution washing is 50°C to 60°C. In this case, the separation of the aluminum foil and / or copper foil from the black powder in the electrode material is improved, and the filtration effect is ensured.

[0087] In some embodiments, in step S10, the time of the sulfate solution washing is 30 min to 40 min.

[0088] In some embodiments, in step S10, the solid-liquid volume ratio of the sulfate solution washing is 1: (2 to 5). In this case, within the range of the solid-liquid volume ratio, the reaction is ensured to be complete, and the excessive waste of experimental chemicals is avoided, thereby reducing the amount of waste liquid in subsequent treatment.

[0089] In some embodiments, in step S10, the sulfate solution washing further comprises ultrasonic-assisted treatment.

[0090] In some embodiments, the ultrasonic frequency of the ultrasonic-assisted treatment is 35 kHz to 45 kHz.

[0091] In some embodiments, in step S10, the sulfate solution washing comprises the following steps:

[0092] S103. Under the condition of ultrasonic-assisted treatment, the electrode material after the water washing treatment is washed with a sulfate solution.

[0093] In some embodiments, a method for separating the current collector and active material of a waste battery is provided, and the method further comprises the following steps:

[0094] S20. The material after the sulfate solution washing is sieved.

[0095] In some embodiments, in the step S20, the mesh size of the sieving is 60 mesh.

[0096] In some embodiments, in the step S20, after the sieving, the proportion of the oversize is more than 45%.

[0097] The following further illustrates with specific examples. For the convenience of illustration, the electrode sheets in the following examples and comparative examples are a mixture of positive electrode sheets and negative electrode sheets, the mass ratio is 1.6:1, and the mass of the obtained electrode material is about 500g.

[0098] Example 1

[0099] Example 1 provides a method for separating the current collector and the active material of the waste battery, the steps are as follows:

[0100] E1. Preparation of electrode material:

[0101] The electrode sheets are broken into less than 5mm and sequentially sieved through 20 mesh, 40 mesh and 60 mesh sieves, and the oversize of the 40 mesh and 60 mesh sieves is obtained as the electrode material.

[0102] E2. Water washing treatment:

[0103] Under the assistance of ultrasonic, the electrode material is subjected to first-stage water washing and second-stage water washing.

[0104] The frequency of the ultrasonic assistance is 40 kHz;

[0105] The solid-liquid volume ratio of the first-stage water washing is 1:5, and the time is 40 min; the solid-liquid volume ratio of the second-stage water washing is 1:2, and the time is 32 min;

[0106] The water washing temperature is 40℃.

[0107] E3. Iron sulfate solution washing:

[0108] Under the assistance of ultrasonic treatment, the Zeta potential of the aluminum foil surface is adjusted by using an iron sulfate solution: the electrode material after the water washing treatment is mixed and stirred with the iron sulfate solution for immersion washing.

[0109] The ultrasonic frequency of the ultrasonic assistance treatment is 40 kHz;

[0110] In the iron sulfate solution, the solutes are composed of iron sulfate, hydrogen peroxide and iron phosphate, the concentration of the iron sulfate is 10g / L, the mass fraction of the hydrogen peroxide is 5%, and the mass fraction of the iron phosphate is 3%, and the pH value of the iron sulfate solution is adjusted to 1 by phosphoric acid;

[0111] The temperature of the iron sulfate solution washing is 60℃, the washing time is 40 min, and the solid-liquid volume ratio is 1:4.

[0112] Example 2

[0113] Example 2 provides a method for separating the current collector and active material of a waste battery, the steps are as follows:

[0114] E1. Preparation of electrode material:

[0115] The electrode sheet is crushed to less than 5 mm and sequentially passed through 20 mesh, 40 mesh and 60 mesh sieves, and the oversize of the 40 mesh and 60 mesh sieves is obtained as the electrode material.

[0116] E2. Water washing treatment:

[0117] Under the assistance of ultrasonic, the electrode material is subjected to first-stage water washing and second-stage water washing.

[0118] The frequency of ultrasonic assistance is 40 kHz;

[0119] The solid-liquid volume ratio of the first-stage water washing is 1:4, and the time is 50 min; the solid-liquid volume ratio of the second-stage water washing is 1:2, and the time is 40 min;

[0120] The water washing temperature is 50°C.

[0121] E3. Iron sulfate solution washing:

[0122] Under the assistance of ultrasonic treatment, the Zeta potential of the aluminum foil surface is adjusted by using an iron sulfate solution: the electrode material after water washing treatment is mixed and stirred with the iron sulfate solution for immersion washing.

[0123] The ultrasonic frequency of ultrasonic assistance treatment is 40 kHz;

[0124] In the iron sulfate solution, the solutes are composed of iron sulfate, hydrogen peroxide and iron phosphate, the concentration of iron sulfate is 8 g / L, the mass fraction of hydrogen peroxide is 1%, and the mass fraction of iron phosphate is 5%, and the pH value of the iron sulfate solution is adjusted to 3 by phosphoric acid;

[0125] The temperature of the iron sulfate solution washing is 50°C, the washing time is 40 min, and the solid-liquid volume ratio is 1:2.

[0126] Example 3

[0127] Example 3 provides a method for separating the current collector and active material of a waste battery, the steps are as follows:

[0128] E1. Preparation of electrode material:

[0129] The electrode sheet is crushed to less than 5 mm and sequentially passed through 20 mesh, 40 mesh and 60 mesh sieves, and the oversize of the 40 mesh and 60 mesh sieves is obtained as the electrode material.

[0130] E2. Water washing treatment:

[0131] The electrode material is subjected to first-stage water washing and second-stage water washing under the assistance of ultrasonic waves.

[0132] The frequency of the ultrasonic assistance is 40 kHz.

[0133] The solid-liquid volume ratio of the first-stage water washing is 1:6, and the time is 30 min; the solid-liquid volume ratio of the second-stage water washing is 1:3, and the time is 30 min.

[0134] The water washing temperature is 50°C.

[0135] E3. Sulfate solution washing:

[0136] Under the assistance of ultrasonic waves, the Zeta potential of the surface of the aluminum foil is adjusted by using a sulfate solution: the electrode material after water washing is mixed with a ferric sulfate solution and subjected to stirring and immersion washing.

[0137] The frequency of the ultrasonic assistance is 40 kHz.

[0138] In the sulfate solution, the solutes are composed of ferric sulfate, hydrogen peroxide and ferric phosphate, the concentration of the ferric sulfate is 12 g / L, the mass fraction of the hydrogen peroxide is 5%, the mass fraction of the ferric phosphate is 13%, and the pH value of the sulfate solution is adjusted to 2 by phosphoric acid.

[0139] The temperature of the sulfate solution washing is 60°C, the washing time is 50 min, and the solid-liquid volume ratio is 1:5.

[0140] Example 4

[0141] Example 4 provides a method for separating the current collector and the active material of a waste battery, and the steps are basically the same as those of Example 1, except that:

[0142] In the sulfate solution, the solutes are composed of sodium sulfate, hydrogen peroxide and sodium bicarbonate, and the pH value is adjusted to 4 by phosphoric acid.

[0143] Example 5

[0144] Example 5 provides a method for separating the current collector and the active material of a waste battery, and the steps are basically the same as those of Example 1, except that:

[0145] In the sulfate solution, the solutes are composed of copper sulfate, hydrogen peroxide and ferrous phosphate, and the pH value is adjusted to 1 by phosphoric acid.

[0146] Example 6

[0147] Example 6 provides a method for separating the current collector and the active material of a waste battery, and the steps are basically the same as those of Example 1, except that:

[0148] The solute of the ferric sulfate solution is composed of ferric sulfate, magnesium sulfate, hydrogen peroxide, sodium citrate and sodium acetate, the concentration of the ferric sulfate is 2 g / L, the concentration of the magnesium sulfate is 8 g / L, the mass fraction of the hydrogen peroxide is 3%, the mass fraction of the sodium citrate is 5%, the mass fraction of the sodium acetate is 5%, and the pH value is adjusted to 2 by phosphoric acid.

[0149] Comparative Example 1

[0150] Comparative Example 1 provides a method for separating the current collector and active material of the waste battery, and the steps are basically the same as those of Example 1, except that:

[0151] In E3, sulfuric acid is used for washing, and the steps are as follows:

[0152] Under the condition of ultrasonic-assisted treatment, the electrode material treated by water washing is washed with sulfuric acid.

[0153] The ultrasonic frequency of the ultrasonic-assisted treatment is 40 kHz.

[0154] The concentration of the sulfuric acid is 10 g / L, the washing temperature is 60°C, the washing time is 40 min, and the solid-liquid volume ratio is 1:4.

[0155] In order to verify the progressiveness of the method for separating the current collector and active material of the waste battery provided by the example of the application, the material washed by the sulfate solution provided by the example of the application and the comparative example is sieved through a 60-mesh sieve, and the aluminum content and copper content of the undersize and oversize are detected, as shown in Table 1 (undersize) and Table 2 (oversize) below. During the washing, the Zeta potential of the surface of the aluminum foil after washing with the sulfate solution / sulfuric acid is detected (the initial Zeta potential of the surface of the aluminum foil is -27.9 mV), and the results are shown in Table 3 below.

[0156]

[0157]

[0158]

[0159] From the above table, the following conclusions can be drawn:

[0160] As can be seen from Table 1 and Table 2, the aluminum content in the undersize solution of the example is <520 ppm; the copper content is <30 ppm, and the aluminum content and copper content of the oversize are higher, which shows that the method for separating the current collector and active material of the waste battery provided by the example of the application uses sulfate to wash the motor material, SO4 2- can electrostatically act on Al2O3 to strip the oxide layer, Fe 3+ can coordinate with PO4 3- to inhibit the formation of aluminum complexes; and the additives lock the Cu 2+, significantly reduces the copper residue in undersize. Further, in combination with the Zeta potential in Table 3, it can be seen that the charge neutralization effect of sulfate (SO4 2- ) in the sulfate solution is used to direct the stripping of the oxide layer, and the simultaneous generation of soluble metal complexes inhibits precipitation, further reducing the copper residue in undersize.

[0161] It should be noted that the present application is not limited to the above-described embodiments. The above-described embodiments are merely examples, and embodiments having substantially the same configuration and exerting the same effects as the technical idea within the scope of the technical solution of the present application are included in the technical scope of the present application. Furthermore, within the scope of the gist of the present application, various modifications that can be thought of by those skilled in the art, other modes constructed by combining part of the configuration elements of the embodiments are also included in the scope of the present application.

Claims

1. A method for separating a current collector from an active material of a waste battery, characterized by, The method comprises the following steps: The electrode material is washed with water and then washed with a sulfate solution; The washing with the sulfate solution comprises adjusting the Zeta potential of the surface of the aluminum foil to a positive value, and the Zeta potential of the surface of the aluminum foil is adjusted to 7 mV-9 mV; The water washing process comprises a first-stage water washing and a second-stage water washing; The solid-liquid volume ratio of the first-stage water washing is 1:4-6; The solid-liquid volume ratio of the second-stage water washing is 1:2-3; The sulfate solution comprises a sulfate, hydrogen peroxide and an additive; The additive comprises at least one of sodium citrate, lithium citrate, sodium acetate, ferrous oxalate, ferrous phosphate, ferric phosphate, sodium carbonate and sodium bicarbonate.

2. The method of claim 1, wherein the spent battery current collector and active material separation method is characterized by, At least one of the following (1)-(4) is satisfied: (1) The step of adjusting the Zeta potential of the surface of the aluminum foil to a positive value comprises: The electrode material after the water washing process is mixed with the sulfate solution for stirring and immersion washing; (2) The pH value of the sulfate solution is 1-4; (3) In the sulfate solution, the concentration of the sulfate is 8 g / L-12 g / L; (4) In the sulfate solution, the sulfate comprises at least one of ferric sulfate, lithium sulfate, sodium sulfate, copper sulfate and magnesium sulfate.

3. The method of claim 2, wherein the spent battery current collector and active material separation method is characterized by, At least one of the following (1)-(5) is satisfied: (1) The temperature of the stirring and immersion washing is 50°C-60°C; (2) In the stirring and immersion washing, the solid-liquid volume ratio of the electrode material to the sulfate solution is 1:2-5; (3) The time of the stirring and immersion washing is 30 min-40 min; (4) The mass fraction of the hydrogen peroxide is 1%-5%; (5) The mass fraction of the additive is 3%-13%.

4. The method for separating the current collector and active material of the waste battery according to any one of claims 1 to 3, characterized by, At least one of the following (1)-(2) is satisfied: (1) The time of the water washing process is 60 min-90 min; (2) The temperature of the water washing process is 40°C-50°C.

5. The method of claim 4, wherein the spent battery current collector and active material separation method is characterized by, The time ratio of the first-stage water washing to the second-stage water washing is 1:0.8-1.

6. The method of claim 4, wherein the spent battery current collector and active material separation method is characterized by, At least one of the following (1)-(2) is satisfied: (1) The water washing process further comprises ultrasonic assistance; (2) The washing with the sulfate solution further comprises ultrasonic assistance.

7. The method of claim 6, wherein the waste battery current collector and active material separation method is characterized by, At least one of the following (1)-(2) is satisfied: (1) The frequency of the ultrasonic assistance is 35 kHz-45 kHz; (2) The ultrasonic frequency of the ultrasonic assistance is 35 kHz-45 kHz.

8. The method of claim 1, wherein the spent battery current collector and active material separation method is characterized by, At least one of the following (1)-(2) is satisfied: (1) The particle size of the electrode material is 0.5 mm-5 mm; (2) The preparation of the electrode material comprises the following steps: The electrode sheet is crushed to below 5 mm and sieved to obtain sieve residue, thereby obtaining the electrode material.

9. The method of claim 8, wherein the waste battery current collector and active material separation method is characterized by, At least one of the following (1)-(2) is satisfied: (1) In the sieving, the mesh number of the sieve is 20-60; (2) The sieve residue accounts for more than 85%.

10. The method of claim 9, wherein the spent battery current collector and active material separation method is characterized by, The particle size of the electrode material is 4 mm-5 mm.

Images