CN108963371B

CN108963371B - Method for recovering valuable metals from waste lithium ion batteries

Info

Publication number: CN108963371B
Application number: CN201810767594.7A
Authority: CN
Inventors: 蔡世德; 谢致平; 苏中府; 曾清全
Original assignee: Ganzhou Hanrui New Energy Technology Co ltd
Current assignee: Ganzhou Hanrui New Energy Technology Co ltd
Priority date: 2018-07-13
Filing date: 2018-07-13
Publication date: 2020-09-25
Anticipated expiration: 2038-07-13
Also published as: CN108963371A

Abstract

The invention discloses a method for recovering valuable metals from waste lithium ion batteries, which comprises the following steps: (1) pretreatment: separating out positive electrode powder and negative electrode powder in the waste lithium ion battery; (2) leaching, namely taking a leaching solution; (3) purifying: adding alkali into the leachate to adjust the pH value, and removing iron, aluminum and copper to obtain a purified solution; (4) component regulation and evaporation concentration: adjusting the proportion of three elements of nickel, cobalt and manganese in the purifying liquid; then evaporating and concentrating, and enriching nickel, cobalt and manganese to set concentration to form precursor preparation liquid; (5) synthesizing: and introducing the precursor preparation solution, a NaOH solution and ammonia water into a reaction kettle, controlling the pH value of the solution in the reaction kettle, reacting, filtering after the reaction is finished, and taking filter residues as a ternary precursor. The leaching solution is purified, supplemented with nickel, cobalt and manganese salts, evaporated and concentrated, and added with a precipitator to directly synthesize a ternary precursor. Has the advantages of short process flow, low raw material consumption, high recovery rate, high product added value and the like.

Description

Method for recovering valuable metals from waste lithium ion batteries

Technical Field

The invention belongs to the field of lithium ion battery waste recovery, and particularly relates to a method for recovering valuable metals in a lithium ion battery.

Background

The lithium ion battery is a rechargeable battery with excellent comprehensive performance, has the advantages of high working voltage, high specific energy, more cycle times, small self-discharge and the like, and is widely applied to the fields of mobile communication, notebook computers, portable tools, electric vehicles and the like. At present, the anode materials of lithium ion batteries in the market mainly comprise lithium cobaltate, lithium iron phosphate, lithium nickel manganese cobalt and the like, all of which contain a large amount of valuable metals, and the lithium ion batteries contain toxic and flammable organic electrolytes, so that the lithium ion batteries can cause serious harm to the environment if not recycled. Valuable metals in the battery waste are recycled, resources can be recycled, and the method has great significance for energy conservation, emission reduction and sustainable development.

The current situation of recycling the lithium ion battery waste materials is as follows: at present, a plurality of methods for treating lithium ion battery waste at home and abroad exist, but the defects of long process flow, high equipment requirement, large raw material consumption, low metal recovery rate, poor product quality and the like exist. The preparation technology of the lithium ion battery is mature day by day, and the recovery technology of the lithium ion battery waste is relatively laggard and needs to be improved and perfected.

CN201180049594.X discloses a method for extracting Ni, Co, Mn and Li from lithium battery waste, and the method adopts two-stage countercurrent leaching and needs to add H2O2, so that the cost is increased, and the process flow is long.

CN201110435394.X discloses a method for separating enriched nickel and cobalt from battery waste leachate, which comprises the following principle processes of reduction acid leaching → oxidation pH adjustment iron removal → vulcanizing agent precipitation → size mixing acid leaching → filtration to obtain nickel and cobalt-containing rich solution. The method has the advantages of long process, high cost and poor working environment.

CN201510242788.1 discloses a method for leaching and recovering metals from lithium ion battery anode waste, the invention provides a method for recovering lithium ion battery anode materials based on metal closed-loop circulation, namely leaching slag is returned to an acid leaching process, a reducing agent is required to be added in the method, on one hand, the closed-loop circulation can increase power consumption, and the leaching slag can be gradually increased, so that industrialization is difficult to realize.

Disclosure of Invention

In order to solve the problems, the invention discloses a method for recovering valuable metals from lithium ion battery waste, which has the advantages of simple process, high recovery rate and good product quality. The specific technical scheme is as follows:

a method for recovering valuable metals from waste lithium ion batteries comprises the following steps:

(1) pretreatment: separating out positive electrode powder and negative electrode powder in the waste lithium ion battery;

(2) leaching:

mixing the positive electrode powder and the negative electrode powder, adding acid, pumping into a high-pressure kettle, and sealing the high-pressure kettle; wherein the acid can be sulfuric acid, hydrochloric acid or nitric acid;

heating;

preserving the heat to obtain a leaching solution;

cooling, and taking the leaching solution;

stirring is kept in the processes of heating, heat preservation and cooling;

(3) purifying: adding alkali into the leachate to adjust the pH value, adding an oxidant to remove iron and aluminum elements in the leachate, and removing copper elements by using an extraction method to obtain a purified solution;

(4) component regulation and evaporation concentration:

regulating and controlling components, namely adding at least one of nickel sulfate, cobalt sulfate and manganese sulfate into the purified liquid to regulate the proportion of the nickel, the cobalt and the manganese in the purified liquid;

then evaporating and concentrating, and enriching nickel, cobalt and manganese to set concentration to form precursor preparation liquid;

(5) synthesizing: and introducing protective gas into the reaction kettle, introducing the precursor preparation solution, the NaOH solution and ammonia water into the reaction kettle, controlling the pH value of the solution in the reaction kettle, reacting, filtering after the reaction is finished, and taking filter residues as a ternary precursor. The ternary precursor can be used as a precursor for preparing a ternary composite anode material.

The leaching solution obtained by the technical scheme of the invention is purified, supplemented with nickel, cobalt and manganese salts, evaporated and concentrated, and added with a precipitator to directly synthesize the ternary precursor. Compared with the traditional process, the technical scheme of the invention has the advantages of short process flow, low raw material consumption, high recovery rate, high added value of products and the like.

In the invention, the anode powder and the cathode powder in the waste lithium ion battery are separated firstly, so that the impurity content in the leaching solution is effectively reduced. The sealed autoclave is adopted, leaching can be carried out under the pressurization condition, the leaching rate of valuable metals is improved, the reaction time is greatly shortened, a reducing agent is not required to be added, the cost is saved, and the working environment is improved; after the leaching solution is purified and nickel-cobalt-manganese salt is supplemented, the ternary precursor is directly prepared, and the product value is higher.

Further, in order to sufficiently recover valuable metals, the filtrate obtained in the step (5) is added to a sodium carbonate solution to recover Li₂CO₃. This process is also referred to as a lithium deposition process.

The sodium carbonate solution can be conveniently filtered to remove impurities so as to avoid bringing unnecessary impurities into the recovered Li₂CO₃In (1). In addition, the adoption of the sodium carbonate solution can also lead the reaction to have faster speed and uniformity. Of course, the sodium carbonate solids may be of sufficient purity, or may be directly fed into the filtrate to recover Li₂CO₃However, sodium carbonate solution is preferred in this application.

Specifically, adding the filtrate into a sodium carbonate solution, and precipitating at 60-100 ℃ for 0.5-2 h to form Li₂CO₃Precipitating, filtering and recovering Li₂CO₃(ii) a The dosage of the sodium carbonate is 1.5-3.0 times of the theoretical dosage, and the mass concentration of the sodium carbonate solution is 15-30%.

Recovery of Li₂CO₃And (4) concentrating the filtrate after lithium precipitation and removing sodium to form a concentrated solution, returning the concentrated solution to the filtrate formed in the step (5), and continuously recovering lithium element in the filtrate to reduce waste and environmental pollution.

Under the conditions, the lithium element in the filtrate can be recovered to the maximum extent, and the waste is reduced.

Preferably, in the step (1), the pretreatment process specifically includes disassembling, blocking, pyrolysis distilling, crushing, screening and sorting the waste lithium ion battery; wherein the temperature during pyrolysis distillation is 200-300 ℃, and the time is 2-8 h. Specifically, after the crushing, the particle size of the particles of the waste lithium ion battery is 80-200 meshes.

After disassembly and separation, the cells can be cut into 10mm by 10mm blocks to facilitate the subsequent processes. By utilizing the pretreatment process, the anode powder and the cathode powder in the battery can be separated to the maximum extent, so that the recovery of the valuable metal in the next process is facilitated.

Preferably, in the step (2), when the positive and negative electrode powders are leached, the leaching temperature is 120-180 ℃, the leaching time is 1-4 h, the liquid-solid ratio L/S is (5-20)/1, the stirring speed is 150-450 r/min, and the end-point pH is 1.0-2.5; the pressure in the kettle is 0.2-1.0 MPa. Where L refers to the liquid volume and S refers to the solid mass.

Under the leaching condition, the anode powder and the cathode powder can be leached, and the method adopts pressure leaching, and has the advantages of high leaching rate, short leaching time, no need of adding a reducing agent, improvement of operating environment and the like compared with the conventional normal-pressure leaching or roasting and then leaching process. Can improve the utilization rate of equipment, reduce labor intensity and reduce production cost.

Preferably: in the step (3), the alkali is NaOH or Na₂CO₃At least one of (1), the oxidant is H₂O₂Or air, the end point pH value is 3.5-4.5, and the copper extractant is one of Lix984, N902 or P204. When air is used as the oxidant, the air can be directly blown into the leaching solution. Wherein, P204 is dioctyl phosphate, Lix984 is a mixture of copper oxime and aldoxime, and the main component of N902 is high-efficiency copper extractant 5-nonylsalicylaldoxime.

The alkali and the oxidant do not bring new impurities, and the price is low and the source is wide; the extractant used preferentially extracts copper, reducing the copper concentration to a lower concentration.

Preferably, in the step (4), the molar ratio of the nickel ions, the cobalt ions and the manganese ions in the solution after the composition regulation is as follows: 8:1:1 or 6:2:2 or 5:2:3 or 1:1: 1; the total concentration of three metal ions of nickel, cobalt and manganese after evaporation concentration is 110-130 g/l. The total concentration is the set concentration in the step (4).

Three metal ions of nickel, cobalt and manganese are prepared according to a certain molar ratio, and the electrochemical performance of different types of batteries can be met. The concentration of metal ions in the concentrated solution is higher, so that the product quality can be better controlled, the productivity can be improved, and the equipment investment and the total liquid amount in the synthesis step can be reduced.

Preferably, in step (5), the protective gas is N₂The synthesis temperature is 50-60 ℃, the synthesis time is 6-30 h, and the synthesis pH value is 10.10-10.30.

N₂As a protective gas, N, which prevents oxidation of metal ions₂No impurities are brought in and the price is low; when the synthesis temperature is 50-60 ℃, the tap density of the ternary precursor is high, and the product quality is good; the synthesis time is 6-30 h, and the ternary precursor has large particles, regular appearance and smooth surface; synthesizing a ternary precursor with the pH value of 10.10-10.30The appearance is single, and the particle size distribution is narrow.

In order to avoid unnecessary waste, in the step (2), after the temperature reduction is finished, discharging is carried out, then the discharged materials are filtered, the filtered liquid is used as a leaching solution to enter a purification process, the filtered leaching slag is washed, and the washing water of the leaching slag is returned to the high-pressure kettle.

The washing water is returned to the high-pressure kettle and used as the bottom liquid in the next leaching process, so that the recovery rate of metal can be improved, and the wastewater amount is reduced.

Drawings

FIG. 1 is a process flow diagram of the present invention.

Detailed Description

The invention relates to a waste lithium ion battery, which comprises a monobasic battery, a binary battery and a ternary battery. Referring specifically to FIG. 1, the present invention will be further described with reference to the following examples and FIG. 1.

Example 1:

and (2) pretreatment, namely weighing 100kg of ternary lithium ion battery waste, disassembling to obtain battery blocks and a shell, shearing the battery blocks to 10mm x 10mm by using a shredder, putting the battery blocks into a pyrolysis furnace for pyrolysis distillation after shearing, crushing the distilled battery materials to the granularity of about 80-100 meshes, and feeding the crushed battery materials into a sieving machine and a sorting machine to obtain 55.61kg of positive electrode powder, 55.90 kg of negative electrode powder, 6.90kg of copper foil, 9.5kg of aluminum foil and 3.0kg of plastic film. The recovery rate of nickel, cobalt, manganese and lithium in the pretreatment is about 96%, and the ratio of copper and aluminum entering the anode powder and the cathode powder is about 1.5% and 5%. The contents of the elements before and after the pretreatment are shown in Table 1.

TABLE 1 content of elements before and after pretreatment of raw materials (% by mass)

Element(s)	Co	Li	Cu	Al	Ni	Mn
							The content of each element in the raw materials	3.17	2.49	7.00	10.00	11.89	5.94
The content of each element of the anode powder and the cathode powder	5.53	4.35	0.19	0.91	20.75	10.37

Leaching: 1kg of the anode powder and the cathode powder obtained after the pretreatment are added with 10L of pure water and H with the theoretical dosage of 1.2 times₂SO₄And (4) mixing slurry, adding the slurry into an autoclave, sealing, stirring and heating. The stirring speed is set to 300r/min, the reaction temperature is set to 150 ℃, when the temperature in the kettle reaches 150 ℃, the pressure is 0.5MPa, the temperature is kept for 2h, the liquid-solid ratio L/S is 10, the leaching end point pH is 1.50, the temperature is reduced to 80 ℃ after the leaching is finished, the materials are discharged, filtered and washed, the dry weight of the leaching residue is 365.6g, the volume of the leaching solution is 9.61L, and the leaching solution enters the purification process. The composition of the leachate is shown in Table 2, and the composition of the leaching residueAnd the leaching rate are shown in Table 3.

TABLE 2 leachate Components

Element(s)	Co	Li	Cu	Al	Ni	Mn
							Concentration (g/L)	5.51	4.26	0.02	0.23	21.38	10.52

TABLE 3 Leaching residue composition and leaching rate of each element

Element(s)	Co	Li	Cu	Al	Ni	Mn
							Extract residue (mass%)	0.02	0.15	0.47	1.86	0.14	0.03
Leaching rate (%)	99.85	98.73	10.82	25.72	99.76	99.90

Purifying the leaching solution: the leaching solution contains a small amount of residual acid and a small amount of Cu, Fe and Al impurity elements. Heating the leaching solution to 80 ℃, adding sodium hydroxide solution to adjust the pH, and adding a small amount of H₂O₂The Fe was oxidized to control the end point pH to 4.2 to form a crude purified solution having a volume of 9.63L and a composition as shown in table 4. After removing Fe and Al, adding a small amount of H into the crude cleaning solution₂SO₄Adjusting pH to 3.5, removing copper by P204 extraction method under the conditions of saponification grade 2, extraction grade 10, washing grade 6, copper removal grade 3, and clarification grade 2 to obtain purified solution with volume of 9.85L and composition shown in Table 5.

TABLE 4 crude purification solution composition

Element(s)	Co	Li	Cu	Al	Ni	Mn
							Concentration (g/L)	5.49	4.24	0.018	0.005	21.29	10.48

TABLE 5 purification solution composition

Element(s)	Co	Li	Cu	Al	Ni	Mn
							Concentration (g/L)	5.31	4.11	0.002	0.001	20.61	9.73

Component regulation and evaporation concentration: 143g of cobalt sulfate crystals and 81g of manganese sulfate crystals were added to the purified liquid, the molar ratio of the three metal ions of nickel, cobalt and manganese was adjusted to n (Ni: Co: Mn) 5:2:3, where n represents the molar ratio, and then the mixture was concentrated by evaporation to a volume of 3.38L of the purified liquid, to obtain a concentrated liquid, the components of which are shown in table 6. The concentrated solution is the precursor preparation solution.

TABLE 6 concentrate composition

Element(s)	Co	Li	Ni	Mn
					Concentration (g/L)	23.87	11.96	59.69	35.93

Synthesizing: introducing sufficient N into the synthesis kettle₂And taking a certain amount of pure water, ammonia water and hydrazine hydrate as base solutions, respectively introducing the concentrated solution, NaOH solution and ammonia water solution into the reaction kettle at a certain flow rate, wherein the synthesis temperature T is 55 ℃, the concentrations of the NaOH solution and the ammonia water solution are respectively 300g/L and 90g/L, the flow rates of the concentrated solution and the ammonia water solution are respectively 0.5L/h and 0.05L/h, and the flow rate of the NaOH solution is controlled by controlling the pH value in the synthesis kettle to be 10.20. And after the synthesis is finished, aging for a period of time, filtering, washing and drying filter residues to obtain a ternary precursor product. And recovering Li element from the filtrate, and performing a lithium precipitation process. The volume of the filtrate was 5.38L, and the contents of the respective elements in the filtrate are shown in Table 7.

TABLE 7 content of each element in the filtrate

Element(s)	Li	Co	Ni	Mn
					Concentration (g/L)	7.15	<0.001	0.006	<0.001

And (3) lithium deposition: the dosage of the sodium carbonate is 2 times of the theoretical dosage of the precipitated lithium, 582.5g of sodium carbonate solid is taken, 1456ml of pure water is added, and the sodium carbonate solution with the mass concentration of 28.6% is prepared under the condition of T-80 ℃. Heating the sodium carbonate solution to 80 ℃ T, preheating the filtrate to 80 ℃, slowly adding the filtrate into the sodium carbonate solution to form a precipitate, continuing to react for 30min after the filtrate is added, and filtering to obtain Li₂CO₃Product and filtrate after lithium removal. Washing Li with a small amount of hot water₂CO₃Post-drying to obtain Li₂CO₃172.88g of product, the lithium carbonate composition is shown in Table 8. 6.52L of filtrate after lithium removal is obtained, and the Li concentration and the total Li yield in the filtrate after lithium removal are shown in Table 9.

TABLE 8 Li₂CO₃Test result of product (% by mass)

Name (R)	Li₂CO₃	Na	Mg	Ca	K	Fe	Zn
								Li₂CO₃Product(s)	99.10	0.09	0.013	0.032	0.003	0.003	0.003
Name (R)	Cu	Mn	Ni	SO4^2-	Cl^-	Hydrochloric acid insoluble substance
								Li₂CO₃Product(s)	0.003	0.003	0.016	0.22	0.01	0.006

TABLE 9 Li concentration in the filtrate after delithiation and total Li yield in the raw material

Element(s)	Li
		Concentration (g/L)	1.05
Total yield of Li in raw materials/%)	69.71

In this example, the leaching residue was not washed, but it is understood that in other examples, the leaching residue may be washed with water and the water for washing the leaching residue may be returned to the autoclave for further use in order to increase the recovery rate.

Example 2:

and (2) preprocessing, namely weighing 100kg of unitary lithium cobaltate battery waste, disassembling to obtain a battery block and a shell, shearing the battery block to 10mm x 15mm by using a shredder, putting the battery block into a pyrolysis furnace for pyrolysis distillation after shearing, crushing the distilled battery material to 100-200 meshes, and feeding the crushed battery material into a sieving machine and a sorting machine to obtain 54.63kg of positive electrode powder, 54.85 kg of copper foil, 9.42kg of aluminum foil and 2.95kg of plastic film. The recovery rate of cobalt and lithium is about 98%, and the ratio of copper and aluminum entering the anode powder and the cathode powder is about 2.2% and 5.80%. The contents of the respective elements before and after the pretreatment are shown in Table 10.

TABLE 10 content of elements before and after pretreatment of raw materials (% by mass)

Element(s)

Co

Li

Cu

Al

Ni

Mn

The content of each element in the raw materials

20.30

2.41

6.80

9.50

/

The content of each element of the anode powder and the cathode powder

36.44

4.32

0.27

1.01

/

Leaching: taking 1kg of the anode powder and the cathode powder obtained after pretreatment, adding 15L of pure water and H with the theoretical dosage of 1.1 times₂SO₄And (4) mixing slurry, adding the slurry into an autoclave, sealing, stirring and heating. The stirring speed is set to 280r/min, the reaction temperature is set to 160 ℃, when the temperature in the kettle reaches 160 ℃, the pressure is 0.62MPa, the temperature is kept for 2h, the liquid-solid ratio L/S is 15, the leaching end point pH is 1.80, the temperature is reduced to 80 ℃ after the leaching is finished, the materials are discharged, filtered and washed, the dry weight of the leached slag is 357.0g, the volume of the leached liquid is 13.82L, and the leached liquid enters the purification process. The composition of the leachate is shown in Table 11, and the composition and leaching rate of the leaching residue are shown in Table 12.

TABLE 11 composition of leachate

Element(s)

Co

Li

Cu

Al

Ni

Mn

Concentration (g/L)

26.34

3.10

0.021

0.19

/

TABLE 12 leaching residue composition and leaching rate of each element

Element(s)

Co

Li

Cu

Al

Ni

Mn

Extract residue (mass%)

0.10

0.68

2.10

/

Leaching rate (%)

99.90

99.16

10.82

25.72

/

Purifying the leaching solution: the leaching solution contains a small amount of residual acid and a small amount of Cu, Fe and Al impurity elements. Heating the leaching solution to 80 ℃, and adding Na₂CO₃The pH was adjusted and air was passed to oxidize Fe therein to control the end point pH to 4.5 to form a crude purified solution having a volume of 13.79L and the composition is shown in table 13. After removing Fe and Al, adding a small amount of H into the crude cleaning solution₂SO₄Adjusting pH to 3.5, removing copper by P204 extraction method under the conditions of saponification grade 2, extraction grade 10, washing grade 6, copper removal grade 3, and clarification grade 2 to obtain purified liquid with volume of 14.28L and composition shown in Table 14.

TABLE 13 crude purification solution composition

Element(s)

Co

Li

Cu

Al

Ni

Mn

Concentration (g/L)

26.34

3.10

0.019

0.003

/

TABLE 14 purification solution composition

Element(s)

Co

Li

Cu

Al

Ni

Mn

Concentration (g/L)

25.18

2.96

0.002

0.001

/

Component regulation and evaporation concentration: 1672.7g of nickel sulfate crystals and 1123.8g of manganese sulfate crystals were added to the purified liquid, the molar ratio of the three metal ions of nickel, cobalt and manganese was adjusted to n (Ni: Co: Mn) 1:1:1, and then the mixture was concentrated by evaporation to a volume of 9.03L of purified liquid, to obtain a concentrated liquid, the components of which are shown in table 15. The concentrated solution is the precursor preparation solution.

TABLE 15 concentrate compositions

Element(s)	Co	Li	Ni	Mn
					Concentration (g/L)	39.82	4.69	40.29	40.05

Synthesizing: introducing sufficient N into the synthesis kettle₂And taking a certain amount of pure water, ammonia water and hydrazine hydrate as base solutions, respectively introducing the concentrated solution, NaOH solution and ammonia water solution into the reaction kettle at a certain flow rate, wherein the synthesis temperature T is 58 ℃, the concentrations of the NaOH solution and the ammonia water solution are respectively 300g/L and 90g/L, the flow rates of the concentrated solution and the ammonia water solution are respectively 1.0L/h and 0.1L/h, and the flow rate of the NaOH solution is controlled by controlling the pH value in the synthesis kettle to be 10.20. And after the synthesis is finished, aging for a period of time, filtering, washing and drying filter residues to obtain a ternary precursor product. And the filtrate is used for recovering Li element and is subjected to a lithium precipitation process. The volume of the filtrate was 14.36L, and the contents of the respective elements in the filtrate are shown in Table 16.

TABLE 16 content of each element in the filtrate

Element(s)	Li	Co	Ni	Mn
					Concentration (g/L)	2.80	<0.001	0.008	<0.001

And (3) lithium deposition:the amount of the sodium carbonate is 2 times of the theoretical amount of the precipitated lithium, 608.9g of the sodium carbonate solid is taken, 1421ml of pure water is added, and the sodium carbonate solution with the mass concentration of 30% is prepared under the condition that the temperature T is 85 ℃. Heating the sodium carbonate solution to 85 ℃, preheating the filtrate to 85 ℃, slowly adding the filtrate into the sodium carbonate solution to form a precipitate, continuing to react for 30min after the filtrate is added, and filtering to obtain Li₂CO₃Product and filtrate after lithium removal. Washing Li with a small amount of hot water₂CO₃Post-drying to obtain Li₂CO₃145.60g of product, lithium carbonate composition is shown in Table 17. 14.20L of filtrate after lithium removal is obtained, and the Li concentration and the total Li yield in the filtrate after lithium removal are shown in Table 18.

TABLE 17 Li₂CO₃Test result of product (% by mass)

Name (R)	Li₂CO₃	Na	Mg	Ca	K	Fe	Zn
								Li₂CO₃Product(s)	99.21	0.08	0.012	0.030	0.002	0.003	0.003
Name (R)	Cu	Mn	Ni	SO4^2-	Cl^-	Hydrochloric acid insoluble substance
								Li₂CO₃Product(s)	0.003	0.003	0.015	0.20	0.01	0.005

TABLE 18 Total Li yield in raw material and Li concentration in filtrate after delithiation

Element(s)	Li
		Concentration (g/L)	0.95
Total Li yield (%)	60.60

In each table of 2 examples, "/" in the data section indicates no detection.

Claims

1. A method for recovering valuable metals from waste lithium ion batteries is characterized by comprising the following steps:

(2) leaching:

mixing the positive electrode powder and the negative electrode powder, adding acid, pumping into a high-pressure kettle, and sealing the high-pressure kettle;

heating;

preserving the heat to obtain a leaching solution;

cooling, and taking the leaching solution;

stirring is kept in the processes of heating, heat preservation and cooling;

in the step (3), the alkali is NaOH or Na₂CO₃At least one of (1), the oxidant is H₂O₂Or air, the end point pH value is 3.5-4.5, and the used copper extractant is one of Lix984, N902 or P204;

(4) component regulation and evaporation concentration:

(5) synthesizing: introducing protective gas into the reaction kettle, introducing the precursor preparation solution, NaOH solution and ammonia water into the reaction kettle, controlling the pH value of the solution in the reaction kettle, reacting, filtering after the reaction is finished, and taking filter residues as a ternary precursor;

adding the filtrate obtained in the step (5) into a sodium carbonate solution, and recovering Li₂CO₃；

In the step (2), when the anode powder and the cathode powder are leached, the leaching temperature is 120-180 ℃, the leaching time is 1-4 h, the liquid-solid ratio L/S is (10-20)/1, the stirring speed is 150-450 r/min, and the end-point pH is 1.0-2.5; the pressure in the kettle is 0.2-1.0 MPa.

2. The method of claim 1, wherein: adding the filtrate into a sodium carbonate solution, and precipitating at 60-100 ℃ for 0.5-2 h to form Li₂CO₃Precipitating, filtering and recovering Li₂CO₃；

The dosage of the sodium carbonate is 1.5-3.0 times of the theoretical dosage, and the mass concentration of the sodium carbonate solution is 15-30%.

3. The method of claim 1, wherein:

in the step (1), the pretreatment process specifically comprises the steps of disassembling, blocking, pyrolyzing and distilling the waste lithium ion battery, crushing, screening and sorting the waste lithium ion battery;

wherein the temperature during pyrolysis distillation is 200-300 ℃, and the time is 2-8 h.

4. The method of claim 1, wherein: after the crushing, the particle size of the waste lithium ion battery particles is 80-200 meshes.

5. The method of claim 1, wherein: in the step (4), the molar ratio of nickel, cobalt and manganese in the solution after the component regulation is as follows: 8:1:1 or 6:2:2 or 5:2:3 or 1:1: 1;

the total concentration of three metal ions of nickel, cobalt and manganese after evaporation concentration is 110-130 g/l.

6. The method of claim 1, wherein the step of removing the metal oxide is performed by a chemical vapor deposition processIn the following steps: in the step (5), the protective gas is N₂The synthesis temperature is 50-60 ℃, the synthesis time is 6-30 h, and the synthesis pH value is 10.10-10.30.

7. The method according to any one of claims 1 to 6, wherein: and (2) after the temperature is reduced, discharging, filtering the discharged materials, taking the filtered liquid as a leaching solution to enter a purification process, washing the filtered leaching residues, and returning the washing water of the leaching residues to the high-pressure kettle.