WO2022062675A1 - Method for recovering waste lithium battery positive electrode material - Google Patents

Abstract

The present invention belongs to the field of the recovery of lithium ion batteries. Disclosed is a method for recovering a waste lithium battery positive electrode material. The method comprises the following steps: (1) carrying out acid leaching on a waste lithium battery positive electrode material, so as to obtain a leachate; (2) adding iron powder to the leachate for reduction, so as to obtain sponge copper and a post-copper-removal liquid; (3) heating the post-copper-removal liquid, then adding a waste battery positive electrode powder, mixing same, carrying out a reaction, regulating the pH to be acidic, and filtering same to obtain an iron-aluminum residue and a filtrate; and (4) carrying out extraction on the filtrate to obtain a nickel cobalt manganese sulfate solution and a raffinate, carrying out coprecipitation on the nickel cobalt manganese sulfate solution to obtain a ternary precursor, adding an alkali liquor to the raffinate, and filtering same to obtain lithium carbonate. In the method for recovering a waste lithium battery positive electrode material provided in the present invention, ferrous ions in the post-copper-removal liquid are used as a reducing agent to leach out lithium manganate, lithium cobalt oxide, and the metal elements nickel, cobalt and manganese from a ternary battery positive electrode plate powder, so that lithium is efficiently recovered therefrom.

Description

A kind of recycling method of waste lithium battery cathode material technical field

The invention belongs to the field of lithium ion battery recycling, and in particular relates to a recycling method for a positive electrode material of a waste lithium battery.

Background technique

Lithium battery recycling has achieved rapid development in China in recent years. Waste ternary lithium batteries are prepared after monomer disassembly (also called crushing, pretreatment), leaching, copper removal, iron and aluminum removal, extraction and co-precipitation. The ternary precursor and lithium salt, and the by-product is Yuanming powder, which has achieved good economic benefits and formed a large scale.

After using iron powder to remove copper, the solution after copper removal contains ferrous ions. In the process of removing iron and aluminum, since ferrous ions are not easy to precipitate, it is necessary to oxidize ferrous ions into iron ions and then adjust the pH to precipitate iron ions. At present, sodium chlorate is commonly used to oxidize ferrous ion, which has the characteristics of high efficiency and fast speed, but chloride ion is introduced, so that the yuanming powder obtained by evaporation and crystallization of the lithium salt section contains chloride ions. The value of yuanming powder is determined by Hundreds of yuan per ton has become tens of yuan per ton or even difficult to sell. A 20,000-ton lithium battery recycling enterprise will lose nearly 10 million yuan every year. At the same time, the introduction of chloride ions will greatly accelerate the corrosion of equipment, especially For MVR evaporators, the chloride ion concentration is so high that expensive titanium alloy materials are used to resist corrosion. Try to use hydrogen peroxide to oxidize ferrous ions, but the temperature of the liquid after copper removal is generally greater than 70 ° C, which is significantly higher than the decomposition temperature of hydrogen peroxide, which is 60 ° C. Adding hydrogen peroxide to violently decompose, it is easy to cause accidents and cause work injuries, and at this time, hydrogen peroxide is effective. The utilization rate is less than ten percent. Therefore, there is an urgent need for a low-cost, high-safety, and ferrous oxide ion method that does not introduce chloride ions.

The valuable metals in the waste ternary electrode powder battery are nickel, cobalt, manganese and lithium, which themselves are a kind of raw material without copper in the waste ternary battery, and lithium cobalt oxide is also a raw material for the recycling of waste ternary battery. The price of one metal ton of pyrolusite is 54 yuan. It can be considered that manganese is a low-value metal, and the price of lithium is currently at a low position. The price of battery-grade lithium carbonate is more than 40,000 a ton. Because pole piece powder, lithium manganate and lithium cobaltate are all the raw materials of the battery recycling line, the raw materials come from a wide range of sources.

At present, waste lithium cobalt oxide and waste pole piece powder are used as recycled raw materials. For waste lithium manganate cathode materials, there is currently a patent number CN101538655A "A method of recycling from waste lithium manganate battery cathode materials", which uses sulfuric acid to leach lithium manganate, lithium leach into leaching solution, manganese in lithium manganate A disproportionation reaction occurs, and part of it becomes tetravalent and precipitates into manganese dioxide, and part of it becomes divalent manganese and leaches into the leaching solution. If it is the waste of lithium manganate that has not entered the lithium battery, the use of manganese dioxide can indeed achieve the method mentioned in the patent, but the waste lithium manganate cathode material contains impurities such as carbon black and alumina, which obviously cannot be used as super capacitors Material. The main components in the leaching solution are lithium sulfate and manganese sulfate. It is necessary to add more expensive liquid alkali to precipitate the manganese ions, which shows that the recovery cost of the leaching solution is relatively high. As a result, its economic benefits are low, and the economic benefits of building a wet recycling production line alone are low, resulting in unmanned recycling and predicament of lithium manganate batteries.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a method for recycling waste and old lithium battery positive electrode materials, which can recycle waste and old lithium manganate, waste and old lithium cobaltate and waste and old ternary positive electrode materials for parallel production, and can recover valuable metals at low cost. Lithium, high safety and the process of oxidizing ferrous ions does not introduce chloride ions.

To achieve the above object, the present invention adopts the following technical solutions:

A method for recycling a positive electrode material of a waste lithium battery, comprising the following steps:

(1) Oxidative acid leaching is performed on the positive electrode material of the waste lithium battery to obtain a leaching solution;

(2) adding iron powder in the leaching solution and reducing, obtaining sponge copper and removing copper solution;

(3) heating the solution after copper removal, adding waste battery positive electrode powder and mixing, reacting, adjusting pH to acidity, and filtering to obtain iron-aluminum slag and filtrate;

(4) extracting the filtrate to obtain a nickel-cobalt-manganese sulfate solution and a raffinate, co-precipitating the nickel-cobalt-manganese sulfate solution to obtain a ternary precursor, adding the lye to the raffinate, and filtering to obtain lithium carbonate.

Preferably, in step (1), the waste lithium battery is also pretreated to obtain battery positive electrode material powder.

More preferably, the pretreatment includes discharging, disassembling, pulverizing, sorting, and sintering to obtain battery positive electrode material powder.

Preferably, in step (1), the temperature of the acid leaching is 60°C-90°C.

Preferably, in step (1), the solution used in the oxidative acid leaching is one of sulfuric acid and hydrogen peroxide.

Preferably, in step (3), the heating is to heat the solution after copper removal to 90°C-110°C.

Preferably, in step (3), the pH of the solution after copper removal is 1.0-3.5.

Preferably, in step (3), the content of ferrous ions in the solution after copper removal is greater than 0.5 g/L.

Preferably, in step (3), the waste battery positive electrode powder is at least one of waste ternary battery positive electrode flake powder, waste lithium manganate powder or waste lithium cobalt oxide powder.

After removing iron and aluminum from waste lithium manganate powder or waste lithium cobaltate powder, the substance that does not participate in the reaction is graphite slag, and the waste ternary battery cathode powder can directly remove iron and aluminum without graphite slag.

More preferably, in terms of mass percentage, the lithium content of the waste ternary battery cathode sheet powder is 3-5%, the nickel content is 12-17%, the cobalt content is 15-19%, and the manganese content is 13-19% . Waste ternary battery cathode powder does not contain iron and copper.

Preferably, in step (3), the reaction time is 4-6 hours, and the reaction temperature is 90°C-110°C.

Preferably, in step (3), the pH adjustment to acidity is to adjust the pH to 3.5-4.5.

Preferably, in step (3), the solution used for adjusting pH to acidity is one of sodium hydroxide or sodium carbonate.

Preferably, in step (3), the iron-aluminum slag is returned to step (1) for acid leaching.

Preferably, in step (4), the lye is sodium carbonate.

The mechanism of step (3) reaction is as follows:

2LiNi _X Co _Y Mn _(1-xy) O ₂ +4H ₂ SO ₄ +2FeSO ₄ =Fe ₂ (SO ₄ ) ₃ +2Ni _X Co _Y Mn _(1-XY) SO ₄ +Li ₂ SO ₄ +H ₂ O Formula (I),

8H ₂ SO ₄ +2LiMn ₂ O ₄ +6FeSO ₄ =Li ₂ SO ₄ +8H ₂ O+3Fe ₂ (SO ₄ ) ₃ +4MnSO ₄ Formula (II),

8H ₂ SO ₄ +2LiCo ₂ O ₄ +6FeSO ₄ =Li ₂ SO ₄ +8H ₂ O+3Fe ₂ (SO ₄ ) ₃ +4CoSO ₄ Formula (III).

When only waste ternary battery positive electrode sheet powder is added, the mechanism is as formula (I). (II), formula (III).

The present invention also provides the application of the above recovery method in recovering valuable metals from the positive electrode material of waste lithium batteries.

Advantages of the present invention:

The method for recovering the positive electrode material of a waste lithium battery provided by the present invention uses ferrous ions in the solution after copper removal as a reducing agent, and leaches lithium manganate, lithium cobaltate, and nickel, cobalt, and manganese in the positive electrode sheet powder of ternary batteries. element, the lithium in it is efficiently recovered, the parallel production of waste ternary cathode materials, waste lithium manganate and waste lithium cobaltate is achieved, and a safe, low-cost and chloride-free ferrous oxide is provided. ionic method.

Description of drawings

1 is a process flow diagram of Embodiment 1 of the present invention;

FIG. 2 is a process flow diagram of Embodiment 2 of the present invention.

detailed description

In order to have an in-depth understanding of the present invention, the preferred experimental scheme of the present invention is described below in conjunction with examples to further illustrate the features and advantages of the present invention. The protection scope of the invention is determined by the scope of the appended claims.

Example 1

A method for recycling a positive electrode material of a waste lithium battery, comprising the following steps:

(1) carrying out acid leaching on the positive electrode material of waste lithium battery to obtain leaching solution and carbon black slag;

(2) adding iron powder in the leaching solution and reducing, obtaining sponge copper and removing copper solution;

( ³ ) the total content of nickel, cobalt and manganese ions is 90g/L, the content of ferrous ions is 8.0g/L, the pH is 1.6, and the volume is 24m . 3.2% nickel content, 16.8% nickel content, 16.0% cobalt content, and 14.1% manganese content were mixed with waste ternary battery cathode flake powder. After 4 hours of reaction, sodium hydroxide was added to adjust the pH value to 4.5, and the filter press washed, Obtain 2.4 tons of iron-aluminum slag and filtrate with ferrous ion content ≤10mg/L;

(4) extract the filtrate to obtain nickel-cobalt-manganese sulfate solution and raffinate, carry out coprecipitation with the nickel-cobalt-manganese sulfate solution to obtain a ternary precursor, add the lye to the raffinate, filter, and get the filter residue to obtain lithium carbonate , the filtrate was concentrated to obtain Yuanming powder.

Drying the iron-aluminum slag in step (3) can obtain a filter residue with a dry weight of about 1.36 tons, wherein the nickel content is 0.02%, the cobalt content is 0.03%, the manganese content is 0.04%, and the lithium content is 0.035%.

The mechanism of step (3) reaction is as follows:

2LiNi _X Co _Y Mn _(1-xy) O ₂ +4H ₂ SO ₄ +2FeSO ₄ =Fe ₂ (SO ₄ ) ₃ +2Ni _X Co _Y Mn _(1-XY) SO ₄ +Li ₂ SO ₄ +H ₂ O Formula (I).

Fig. 1 is the process flow chart of Example 1 (the black box represents the processing procedure, and the white box represents the obtained substance or the added substance, such as the leaching solution obtained by acid leaching of the battery).

Example 2

A method for recycling a positive electrode material of a waste lithium battery, comprising the following steps:

(1) carrying out acid leaching on the positive electrode material of waste lithium battery to obtain leaching solution and carbon black slag;

(2) adding iron powder in the leaching solution and reducing, obtaining sponge copper and removing copper solution;

(3) The total content of nickel, cobalt and manganese ions is 93g/L, the content of ferrous ions is 5.9g/L, the pH is 1.5, and the volume is 189L after copper removal. The liquid is heated to 95 ° C, and then 2.01 kg of lithium content is added. 3.3%, nickel content 13.4%, cobalt content 15.2%, manganese content 18.1%, carbon content 12.7% waste mixed powder (waste ternary battery cathode sheet powder, waste lithium manganate and waste lithium cobalt oxide powder ) mixing, after reacting for 4h, adding sodium hydroxide to adjust the pH value to 4.5, press filtration and washing to obtain 0.34 kg of iron-aluminum slag and filtrate with ferrous ion content≤10mg/L;

(4) extract the filtrate to obtain nickel-cobalt-manganese sulfate solution and raffinate, carry out coprecipitation with the nickel-cobalt-manganese sulfate solution to obtain a ternary precursor, add the lye to the raffinate, filter, and get the filter residue to obtain lithium carbonate , the filtrate was concentrated to obtain Yuanming powder.

0.34 kg of filter residue in step (3), wherein the manganese content is 6.8%, and the lithium content is 0.45%, it can be drawn that the ratio of nickel cobalt manganese entering the filtrate is more than 98%, and the ratio of lithium entering the filtrate is 97%, The economy is very good; the filter residue is returned to step (1), and sulfuric acid + hydrogen peroxide is used to carry out reducing acid leaching on the filter residue to obtain 0.22 kg of carbon black residue. The manganese content in the carbon black residue is 0.14% and the lithium content is 0.003%. %, the total metal leaching rate is greater than 99%.

The reaction mechanism is as follows:

2LiNi _X Co _Y Mn _(1-xy) O ₂ O ₂ +4H ₂ SO ₄ +2FeSO ₄ =Fe ₂ (SO ₄ ) ₃ +2Ni _X Co _Y Mn _(1-XY) SO ₄ +Li ₂ SO ₄ +H ₂ O formula (I),

8H ₂ SO ₄ +2LiMn ₂ O ₄ +6FeSO ₄ =Li ₂ SO ₄ +8H ₂ O+3Fe ₂ (SO ₄ ) ₃ +4MnSO ₄ Formula (II),

8H ₂ SO ₄ +2LiCo ₂ O ₄ +6FeSO ₄ =Li ₂ SO ₄ +8H ₂ O+3Fe ₂ (SO ₄ ) ₃ +4CoSO ₄ Formula (III).

FIG. 2 is a process flow chart of Example 2 (the black box represents the processing procedure, and the white box represents the obtained substance or the added substance, such as battery powder obtained by pretreatment of the battery).

Comparative Example 1

A method for recycling a positive electrode material of a waste lithium battery, comprising the following steps:

(1) carrying out acid leaching on the positive electrode material of waste lithium battery to obtain leaching solution and carbon black slag;

(2) adding iron powder in the leaching solution and reducing, obtaining sponge copper and removing copper solution;

(3) the total content of nickel, cobalt and manganese ions is 90g/L, the content of ferrous ions is 8.0g/L, the pH is 1.6, and the volume is 24m ³ The post-copper removal solution is heated to 100 ° C, and then sodium chlorate is added to mix , after 4h of reaction, add sodium hydroxide to adjust the pH value to 4.5, press filter and wash to obtain iron-aluminum slag and iron-removing aluminum filtrate;

(4) extract the filtrate to obtain nickel-cobalt-manganese sulfate solution and raffinate, carry out coprecipitation with the nickel-cobalt-manganese sulfate solution to obtain a ternary precursor, add the lye to the raffinate, filter, and get the filter residue to obtain lithium carbonate , the filtrate was concentrated to obtain Yuanming powder.

Detect the liquid element composition after removing copper in Example 1-2 and Comparative Example 1, the results are as shown in Table 1:

Table 1

Detect the elemental composition of sponge copper in Examples 1-2 and Comparative Example 1, and the results are shown in Table 2:

Table 2

	NiCoMn(%)	Cu(%)	Fe(%)	Al(%)
Example 1	0.04	85.1	1.37	0
Example 2	0.04	85.2	1.36	0
Comparative Example 1	0.04	85.1	1.37	0

Detect the elemental composition of iron-aluminum slag in Examples 1-2 and Comparative Example 1, and the results are shown in Table 3:

Table 3: Table of element content of iron-aluminum slag

It can be seen from Table 3 that there is no significant difference between the lithium content and the lithium content of the filter residue added with sodium chlorate, the content of the main elements nickel and cobalt is basically the same, and the content of nickel, cobalt and manganese is 0.19% relative to the average manganese content of the filter residue added with sodium chlorate. About 5 times of the slag, due to the high degree of reaction and complete reaction, the slag is mainly graphite.

Detect the nickel-cobalt-manganese sulfate composition in Example 1-2 and Comparative Example 1, and the results are shown in Table 4:

Table 4: Composition of Nickel Cobalt Manganese Sulfate

Detect the elemental composition of lithium carbonate in Example 1-2 and Comparative Example 1, the results are as shown in Table 5:

Table 5: Lithium carbonate element composition table

Detect the elemental composition of Yuan Ming powder in Example 1-2 and Comparative Example 1, the results are as shown in Table 6:

Table 6: Elemental Composition of Yuanming Powder

From Table 6, it can be obtained that the sodium chlorate ferrous oxide is utilized, and the Yuan Ming powder contains chloride ions. Chloride ion can be directly sold Yuan Mingfen.

The recovery rate and cost of each element in Example 1-2 and Comparative Example 1, the results are as shown in Table 7:

Table 7

element	Ni	Co	Mn	Li	Fe	Cu
Example 1	99.49%	99.2%	98.79%	95.35%	99.8%	99.85%
Example 2	99.49%	99.2%	98.79%	95.85%	99.8%	99.85%
Comparative Example 1	97.50%	96.0%	95.2%	94.2%	99.2%	99.3%

As can be known from Table 7, when the production raw materials are converted into production auxiliary materials, the recovery rate of nickel, cobalt and manganese is all higher than that of Comparative Example 1, the reaction is carried out very thoroughly, and a good practical application effect has been achieved.

A method for recycling a cathode material of a waste lithium battery provided by the present invention has been described in detail above. The principles and implementations of the present invention are described with specific examples in this paper. The method of the invention and its core ideas, including the best mode, also enable any person skilled in the art to practice the invention, including making and using any devices or systems, and performing any incorporated methods. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, several improvements and modifications can also be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other embodiments are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.

Claims (10)

1. A method for recycling a positive electrode material of a waste lithium battery, characterized in that it comprises the following steps:

   (1) oxidative acid leaching is performed on the positive electrode material of the waste lithium battery to obtain a leaching solution;

   (2) adding iron powder in the leaching solution and reducing, obtaining sponge copper and removing copper solution;

   (3) heating the solution after copper removal, adding waste battery positive electrode powder and mixing, reacting, adjusting pH to acidity, and filtering to obtain iron-aluminum slag and filtrate;

   (4) extracting the filtrate to obtain a nickel-cobalt-manganese sulfate solution and a raffinate, coprecipitating the nickel-cobalt-manganese sulfate solution to obtain a ternary precursor, adding the lye to the raffinate, and filtering to obtain lithium carbonate.
2. The recovery method according to claim 1, characterized in that, in step (1), the temperature of the acid leaching is 60°C-90°C.
3. The recovery method according to claim 1, characterized in that, in step (1), the solution used in the oxidative acid leaching is one of sulfuric acid and hydrogen peroxide.
4. The recycling method according to claim 1, wherein in step (3), the waste battery positive electrode powder is at least one of waste ternary battery positive electrode sheet powder, waste lithium manganate powder or waste lithium cobalt oxide powder kind.
5. The recovery method according to claim 4, characterized in that, in terms of mass percentage, the lithium content of the waste ternary battery positive electrode sheet powder is 3-5%, the nickel content is 12-17%, and the cobalt content is 15-15% 19%, manganese content is 13-19%.
6. The recovery method according to claim 1, characterized in that, in step (3), the reaction time is 4-6 hours, and the reaction temperature is 90°C-110°C.
7. recovery method according to claim 1, is characterized in that, in step (3), the solution that described pH adjustment uses is a kind of in sodium hydroxide or sodium carbonate.
8. The recovery method according to claim 1, characterized in that, in step (3), the iron-aluminum slag is returned to step (1) for acid leaching.
9. The recovery method according to claim 1, is characterized in that, in step (4), described lye is sodium carbonate.
10. Application of the recovery method according to any one of claims 1 to 9 in the recovery of valuable metals from the positive electrode material of waste lithium batteries.

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