阅读说明：本技术 粗制氢氧化钴和废旧三元正极联合处理的方法 (Method for combined treatment of crude cobalt hydroxide and waste ternary positive electrode ) 是由 张勤俭 肖超 訚硕 李攀 赵思佳 邓海龙 罗进爱 欧阳俊岱 于 2021-10-28 设计创作，主要内容包括：本申请提供一种粗制氢氧化钴和废旧三元正极联合处理的方法,涉及锂离子电池领域。粗制氢氧化钴和废旧三元正极联合处理的方法,包括：将所述粗制氢氧化钴与浓硫酸、双氧水混合,进行还原酸浸得到第一酸浸液；将所述第一酸浸液与废旧三元正极片混合,浸泡得到第二酸浸液,然后固液分离得到正极活性材料和含钴溶液；将所述正极活性材料在空气和二氧化硫的混合气体存在下,还原浸出得到含有有价金属的溶液；所述含钴溶液后处理得到钴类化合物。本申请提供的粗制氢氧化钴和废旧三元正极联合处理的方法,实现了两种含钴原料的同时处理和配合使用,降低了酸碱消耗量。(The application provides a method for combined treatment of crude cobalt hydroxide and a waste ternary anode, and relates to the field of lithium ion batteries. The method for jointly treating the crude cobalt hydroxide and the waste ternary positive electrode comprises the following steps: mixing the rough cobalt hydroxide with concentrated sulfuric acid and hydrogen peroxide, and carrying out reduction acid leaching to obtain a first acid leaching solution; mixing the first acid leaching solution with the waste ternary positive plate, soaking to obtain a second acid leaching solution, and then carrying out solid-liquid separation to obtain a positive active material and a cobalt-containing solution; reducing and leaching the positive active material in the presence of a mixed gas of air and sulfur dioxide to obtain a solution containing valuable metals; and carrying out post-treatment on the cobalt-containing solution to obtain a cobalt compound. The method for combined treatment of the rough cobalt hydroxide and the waste ternary anode realizes simultaneous treatment and matched use of two cobalt-containing raw materials, and reduces the consumption of acid and alkali.)

1. A method for combined treatment of crude cobalt hydroxide and a waste ternary positive electrode is characterized by comprising the following steps:

mixing the rough cobalt hydroxide with concentrated sulfuric acid and hydrogen peroxide, and carrying out reduction acid leaching to obtain a first acid leaching solution;

mixing the first acid leaching solution with the waste ternary positive plate, soaking to obtain a second acid leaching solution, and then carrying out solid-liquid separation to obtain a positive active material and a cobalt-containing solution;

reducing and leaching the positive active material in the presence of a mixed gas of air and sulfur dioxide to obtain a solution containing valuable metals; and carrying out post-treatment on the cobalt-containing solution to obtain a cobalt compound.

2. The method of claim 1, wherein the mixing of the crude cobalt hydroxide with the concentrated sulfuric acid and the hydrogen peroxide solution further comprises:

slurrying the crude cobalt hydroxide with water;

preferably, the liquid-to-solid ratio of water to the crude cobalt hydroxide is (5-6) ml:1g of the total weight of the composition.

3. The method according to claim 1, characterised in that the pH of the first pickle liquor is 1-1.5;

preferably, the first pickle liquorMiddle Co²⁺The content of (A) is 40g/L-70g/L, and the content of aluminum is less than or equal to 10 mg/L.

4. The method according to claim 1, wherein the waste ternary positive electrode sheets are pre-crushed into blocks of 4cm-6 cm.

5. The method according to claim 1, wherein the liquid-solid ratio of the first acid leaching solution to the waste ternary positive electrode plate is (10-20) mL:1g of the total weight of the composition.

6. The method according to claim 1, wherein the soaking is performed under stirring and ultrasonic conditions;

preferably, the stirring speed is 150r/min-200r/min, and the ultrasonic frequency of the ultrasonic wave is 30KHz-50 KHz;

preferably, the soaking time is 30min-60 min.

7. The method of claim 1, wherein the solid-liquid separation comprises a primary filtration and a secondary filtration;

the first-stage filtration is carried out to obtain a current collector and filtrate, and the second-stage filtration is carried out to obtain the anode active material and the cobalt-containing solution;

preferably, Co is present in said cobalt-containing solution²⁺Has a content of 45g/L to 75g/L, Al³⁺The concentration is less than or equal to 200mg/L, and the pH is 1.5-2.5;

preferably, the aperture of the screen mesh of the primary filtration is 0.5cm-1cm, and the aperture of the screen mesh of the secondary filtration is 0.5mm-2 mm.

8. The method of claim 1, wherein the post-processing comprises: removing iron and aluminum and extracting by a chemical precipitation method.

9. The method of claim 1, wherein the reductive leaching is preceded by:

crushing the positive electrode active material, and then slurrying with water;

preferably, the liquid-solid ratio slurried with water is (4-6) ml:1g of the total weight of the composition.

10. The method according to any one of claims 1 to 9, wherein the pressure of the reductive leaching is 0.1MPa to 0.3MPa, the temperature is 50 ℃ to 90 ℃ and the time is 2 to 3 hours;

preferably, the amount of sulphur dioxide used is 2 to 4 times the theoretical amount required for reduction.

Technical Field

The application relates to the field of lithium ion batteries, in particular to a method for jointly treating crude cobalt hydroxide and a waste ternary anode.

Background

With the rapid development of the new energy automobile industry, the market scale of the ternary lithium battery is rapidly increased. The recovery of the anode material of the waste ternary lithium battery not only can bring great environmental benefits, but also brings economic benefits and social benefits.

At present, the recovery of the anode material of the waste ternary lithium battery is mainly carried out by a wet method with mild conditions and low energy consumption, and the wet method process mainly comprises the steps of stripping a waste ternary anode plate current collector, leaching valuable metals, purifying a solution and the like, wherein the stripping of the current collector can be realized by a method of corroding an aluminum foil by 0.4-0.8mol/L dilute sulfuric acid, and the leaching of the valuable metals is usually carried out by reducing and leaching by using sulfuric acid and a reducing agent.

Excessive sulfuric acid and reducing agent are required to be added during reduction and acid leaching of the positive active material, gas is generated, bubbling and overflowing are easily caused, and the economic cost is increased. Meanwhile, a large amount of acid-base reagents are needed in the treatment process of the positive active material and in the subsequent harmless treatment, so that the cost of the recovery treatment is high on one hand, and the cost of the harmless treatment is high on the other hand.

Disclosure of Invention

The application aims to provide a method for jointly treating crude cobalt hydroxide and a waste ternary positive electrode so as to solve the problems.

In order to achieve the purpose, the following technical scheme is adopted in the application:

a method for combined treatment of crude cobalt hydroxide and a waste ternary cathode comprises the following steps:

mixing the rough cobalt hydroxide with concentrated sulfuric acid and hydrogen peroxide, and carrying out reduction acid leaching to obtain a first acid leaching solution;

mixing the first acid leaching solution with the waste ternary positive plate, soaking to obtain a second acid leaching solution, and then carrying out solid-liquid separation to obtain a positive active material and a cobalt-containing solution;

reducing and leaching the positive active material in the presence of a mixed gas of air and sulfur dioxide to obtain a solution containing valuable metals; and carrying out post-treatment on the cobalt-containing solution to obtain a cobalt compound.

Preferably, before mixing the crude cobalt hydroxide with the concentrated sulfuric acid and the hydrogen peroxide, the method further comprises:

slurrying the crude cobalt hydroxide with water;

preferably, the liquid-to-solid ratio of water to the crude cobalt hydroxide is (5-6) ml:1g of the total weight of the composition.

Preferably, the pH of the first pickle liquor is 1-1.5;

preferably, Co in the first pickle liquor²⁺The content of (A) is 40g/L-70g/L, and the content of aluminum is less than or equal to 10 mg/L.

Preferably, the waste ternary positive plates are pre-crushed into blocks of 4cm-6 cm.

Preferably, the liquid-solid ratio of the first acid leaching solution to the waste ternary positive plate is (10-20) mL:1g of the total weight of the composition.

Preferably, the soaking is performed under stirring and ultrasonic conditions;

preferably, the stirring speed is 150r/min-200r/min, and the ultrasonic frequency of the ultrasonic wave is 30KHz-50 KHz;

preferably, the soaking time is 30min-60 min.

Preferably, the solid-liquid separation comprises primary filtration and secondary filtration;

the first-stage filtration is carried out to obtain a current collector and filtrate, and the second-stage filtration is carried out to obtain the anode active material and the cobalt-containing solution;

preferably, Co is present in said cobalt-containing solution²⁺Has a content of 45g/L to 75g/L, Al³⁺The concentration is less than or equal to 200mg/L, and the pH is 1.5-2.5;

preferably, the aperture of the screen mesh of the primary filtration is 0.5cm-1cm, and the aperture of the screen mesh of the secondary filtration is 0.5mm-2 mm.

Preferably, the post-processing comprises: removing iron and aluminum and extracting by a chemical precipitation method.

Preferably, the reduction leaching further comprises:

crushing the positive electrode active material, and then slurrying with water;

preferably, the liquid-solid ratio slurried with water is (4-6) ml:1g of the total weight of the composition.

Preferably, the pressure of the reduction leaching is 0.1MPa to 0.3MPa, the temperature is 50 ℃ to 90 ℃, and the time is 2 to 3 hours;

preferably, the amount of sulphur dioxide used is 2 to 4 times the theoretical amount required for reduction.

Compared with the prior art, the beneficial effect of this application includes:

according to the method for combined treatment of the rough cobalt hydroxide and the waste ternary anode, the acid leaching solution obtained after rough cobalt hydroxide reduction acid leaching is used for acid leaching of the waste ternary anode plate, so that on one hand, the amount of acid used in the waste ternary anode recovery process is reduced, on the other hand, the pH of the solution obtained after acid leaching of the waste ternary anode is increased, and the consumption of alkali in the subsequent preparation of cobalt compounds by iron and aluminum removal is reduced; meanwhile, a small amount of nickel, cobalt and manganese enter the acid leaching solution during acid leaching of the waste ternary positive electrode, enrichment and recovery are not needed to be considered independently, and the treatment cost is further reduced.

In addition, the crude cobaltous hydroxide immersion liquid with relatively high pH value is adopted to replace dilute sulfuric acid to soak the waste ternary anode, so that the equal separation effect of the aluminum foil and the anode active material can be realized, but compared with the dilute sulfuric acid immersion, the method has the advantages that less aluminum is leached in the solution, the aluminum foil can be completely stripped, and basically no aluminum scraps are mixed in the separated anode active material.

The air and sulfur dioxide mixed gas is adopted to replace sulfuric acid and a reducing agent for reduction leaching, so that the dual purposes of one product and two purposes are realized (the formed sulfurous acid can be used as acid to leach valuable metals in filter residues, and can be used as a reducing agent to reduce high-price metals into easily-leached low-price metals), and the production cost is reduced. The mixed gas of sulfur dioxide and air discharged after the reduction leaching is finished can be used for the next reduction acid leaching after the composition adjustment, thereby realizing the best use of the materials and no exhaust gas discharge.

Drawings

To more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments are briefly described below, and it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope of the present application.

Fig. 1 is a schematic flow chart of a method for combined treatment of crude cobalt hydroxide and a waste ternary cathode provided in example 1.

Detailed Description

The terms as used herein:

"prepared from … …" is synonymous with "comprising". The terms "comprises," "comprising," "includes," "including," "has," "having," "contains," "containing," or any other variation thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

The conjunction "consisting of … …" excludes any unspecified elements, steps or components. If used in a claim, the phrase is intended to claim as closed, meaning that it does not contain materials other than those described, except for the conventional impurities associated therewith. When the phrase "consisting of … …" appears in a clause of the subject matter of the claims rather than immediately after the subject matter, it defines only the elements described in the clause; other elements are not excluded from the claims as a whole.

When an amount, concentration, or other value or parameter is expressed as a range, preferred range, or as a range of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed. For example, when the range "1 ~ 5" is disclosed, the ranges described should be construed to include the ranges "1 ~ 4", "1 ~ 3", "1 ~ 2 and 4 ~ 5", "1 ~ 3 and 5", and the like. When a range of values is described herein, unless otherwise stated, the range is intended to include the endpoints thereof and all integers and fractions within the range.

In these examples, the parts and percentages are by mass unless otherwise indicated.

"part by mass" means a basic unit of measure indicating a mass ratio of a plurality of components, and 1 part may represent any unit mass, for example, 1g or 2.689 g. If we say that the part by mass of the component A is a part by mass and the part by mass of the component B is B part by mass, the ratio of the part by mass of the component A to the part by mass of the component B is a: b. alternatively, the mass of the A component is aK and the mass of the B component is bK (K is an arbitrary number, and represents a multiple factor). It is unmistakable that, unlike the parts by mass, the sum of the parts by mass of all the components is not limited to 100 parts.

"and/or" is used to indicate that one or both of the illustrated conditions may occur, e.g., a and/or B includes (a and B) and (a or B).

A method for combined treatment of crude cobalt hydroxide and a waste ternary cathode comprises the following steps:

mixing the rough cobalt hydroxide with concentrated sulfuric acid and hydrogen peroxide, and carrying out reduction acid leaching to obtain a first acid leaching solution;

mixing the first acid leaching solution with the waste ternary positive plate, soaking to obtain a second acid leaching solution, and then carrying out solid-liquid separation to obtain a positive active material and a cobalt-containing solution;

reducing and leaching the positive active material in the presence of a mixed gas of air and sulfur dioxide to obtain a solution containing valuable metals; and carrying out post-treatment on the cobalt-containing solution to obtain a cobalt compound.

The reaction equation of sulfur dioxide in the system is as follows:

SO₂+H₂O＝H₂SO₃

2LiMn_xNi_yCo_(1-x-y)+3H₂SO₃＝2(1-x-y)CoSO₄+2xMnSO₄+2yNiSO₄+Li₂SO₄+3H₂O

it should be noted that, when the pole piece is acid-leached, a small amount of aluminum is dissolved and enters the second acid leaching solution, and the next procedure after the rough cobalt hydroxide reduction leaching according to the conventional process is to adjust the pH value for precipitation and impurity removal. Although the aluminum content of the second acid leaching solution is increased after the combination process, the increase amount is small, and the effect of precipitating and removing iron and aluminum according to the conventional process is not influenced.

The cobalt compound referred to herein is generally referred to as cobalt chloride or cobalt sulfate.

In an optional embodiment, before mixing the crude cobalt hydroxide with the concentrated sulfuric acid and the hydrogen peroxide, the method further includes:

slurrying the crude cobalt hydroxide with water;

in an alternative embodiment, the liquid-to-solid ratio of water to the crude cobalt hydroxide is (5-6) ml:1g of the total weight of the composition.

Alternatively, the liquid-to-solid ratio of water to the crude cobalt hydroxide may be 5ml:1g, 5.5 ml:1g, 6 ml:1g or (5-6) ml:1 g.

In an alternative embodiment, the pH of the first pickle liquor is 1-1.5;

in an alternative embodiment, the first pickle liquor comprises Co²⁺The content of (A) is 40g/L-70g/L, and the content of aluminum is less than or equal to 10 mg/L.

Optionally, the pH of the first pickle liquor may be any value between 1, 1.1, 1.2, 1.3, 1.4, 1.5 or 1-1.5; co in the first pickle liquor²⁺The content of (b) can be 40g/L, 50g/L, 60g/L, 70g/L or any value between 40g/L and 70g/L, and the content of aluminum can be 1mg/L, 2mg/L, 3mg/L, 4mg/Lmg/L, 5mg/L, 6mg/L, 7mg/L, 8mg/L, 9mg/L, 10mg/L or any value between 10mg/L or less.

In an alternative embodiment, the waste ternary positive electrode sheets are pre-crushed into blocks of 4cm-6 cm.

Optionally, the waste ternary positive plate is pre-crushed into blocks of any value of 4cm, 5cm, 6cm or 4cm-6 cm.

In an optional embodiment, the liquid-solid ratio of the first pickle liquor to the waste ternary positive electrode plate is (10-20) mL:1g of the total weight of the composition.

Optionally, the liquid-solid ratio of the first acid leaching solution to the waste ternary positive electrode may be 10mL:1g, 11 mL:1g, 12 mL:1g, 13 mL:1g, 14 mL:1g, 15mL:1g, 16 mL:1g, 17 mL:1g, 18 mL:1g, 19 mL:1g, 20mL:1g or (10-20) mL:1 g.

In an alternative embodiment, the soaking is performed under stirring and ultrasonic conditions;

in an optional embodiment, the stirring speed is 150r/min-200r/min, and the ultrasonic frequency of the ultrasonic wave is 40 KHz;

in an alternative embodiment, the soaking time is 30min to 60 min.

The stirring is usually carried out by mechanical stirring, and the soaking is carried out at normal temperature.

Optionally, the stirring speed may be any value of 150r/min, 160r/min, 170r/min, 180r/min, 190r/min, 200r/min or 150r/min-200r/min, and the ultrasonic frequency of the ultrasonic wave may be 30KHz, 40KHz, 50KHz or 30KHz-50 KHz; the soaking time can be any value of 30min, 40min, 50min, 60min or 30min-60 min.

In an alternative embodiment, the solid-liquid separation comprises a first stage filtration and a second stage filtration;

the first-stage filtration is carried out to obtain a current collector and filtrate, and the second-stage filtration is carried out to obtain the anode active material and the cobalt-containing solution;

in an alternative embodiment, the cobalt-containing solutionCo in liquid²⁺Has a content of 45g/L to 75g/L, Al³⁺The concentration is less than or equal to 200mg/L, and the pH is 1.5-2.5;

during the soaking process a small amount of valuable metals, mainly cobalt, is leached, which results in an increased concentration of cobalt ions in the cobalt-containing solution relative to the first pickling liquor. Iron (Fe) in acid immersion liquid after pole piece immersion²⁺) Copper (Cu)²⁺) Manganese (Mn)²⁺) The content is basically unchanged, the reaction rate of the sulfate and aluminum at room temperature is extremely slow and can be ignored, and the aluminum (Al)³⁺) The content is increased to below 200mg/L (can be controlled to be below 150 mg/L), and the TOC (total organic carbon) content is low and is generally below 30 mg/L.

In an alternative embodiment, the first stage filtration has a mesh size of 0.5cm to 1cm and the second stage filtration has a mesh size of 0.5mm to 2 mm.

Optionally, Co in the cobalt-containing solution²⁺The content of (b) can be 45g/L, 50g/L, 55g/L, 60g/L, 65g/L, 70g/L, 75g/L or any value between 45g/L and 75g/L, Al³⁺The concentration can be any value between 10mg/L, 50mg/L, 100mg/L, 150mg/L, 200mg/L or less than or equal to 200mg/L, and the pH can be any value between 1.5, 2, 2.5 or 1.5 and 2.5; the aperture of the screen mesh of the primary filtration can be any value between 0.5cm, 0.6cm, 0.7cm, 0.8cm, 0.9cm, 1cm or 0.5cm and 1cm, and the aperture of the screen mesh of the secondary filtration can be any value between 0.5mm, 1mm, 1.5mm, 2mm or 0.5mm and 2 mm.

In an alternative embodiment, the post-processing comprises: removing iron and aluminum and extracting by a chemical precipitation method.

In an optional embodiment, the reducing leaching further comprises, before the reducing leaching:

crushing the positive electrode active material, and then slurrying with water;

in an alternative embodiment, the liquid-solid ratio slurried with water is (4-6) ml:1g of the total weight of the composition.

Optionally, the slurried liquid-solid ratio may be 4 ml:1g, 5ml:1g, 6 ml:1g or (4-6) ml:1 g.

In an alternative embodiment, the pressure of the reduction leaching is 0.1MPa to 0.3MPa, the temperature is 50 ℃ to 90 ℃, and the time is 2 to 3 hours;

in an alternative embodiment, the amount of sulphur dioxide used is 2 to 4 times the theoretical amount required for reduction.

The introduction of sulfur dioxide gas with 2-4 times of theoretical value (increasing sulfur dioxide excess coefficient) and the pressure leaching mode can promote the sulfur dioxide to be dissolved in water to form sulfurous acid, inhibit the decomposition of the sulfurous acid, effectively improve the reduction leaching rate and shorten the reaction time.

Optionally, the pressure of the reduction leaching may be any value between 0.1MPa, 0.2MPa, 0.3MPa or 0.1MPa and 0.3MPa, the temperature may be any value between 50 ℃, 60 ℃, 70 ℃, 80 ℃, 90 ℃ or 50 ℃ and 90 ℃, and the time may be any value between 2h, 2.5h, 3h or 2h and 3 h; the usage amount of the sulfur dioxide is 2 times, 3 times, 4 times or any value between 2 and 4 times of the theoretical usage amount required by reduction.

Embodiments of the present application will be described in detail below with reference to specific examples, but those skilled in the art will appreciate that the following examples are only illustrative of the present application and should not be construed as limiting the scope of the present application. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

Example 1

As shown in fig. 1, the embodiment provides a method for combined treatment of crude cobalt hydroxide and a waste ternary cathode, which comprises the following specific steps:

(1) adding the crude cobalt hydroxide into pure water for slurrying, wherein the liquid-solid ratio is 5mL:1 g; adding a proper amount of concentrated sulfuric acid to ensure that Co in acid leaching solution after acid leaching is contained²⁺＝65.1g/L，pH＝1.41。

(2) And (2) crushing the waste ternary positive plate into small pieces of 4-6cm, adding the small pieces into the pickle liquor obtained in the step (1), wherein the liquor-solid ratio is 15mL:1g, stirring, and carrying out ultrasonic cleaning and soaking for 50 min.

(3) The pickle liquor is filtered for the first time to obtain a current collector (a massive aluminum foil), and then filtered for the second time to obtain the positive electrodeVery active materials, complete separation can be achieved. At this time, Co in the pickle liquor²⁺＝68.3g/L，Al³⁺The concentration is 147.8mg/L, pH is 2.16, and the pickle liquor can be subjected to aluminum removal by a chemical precipitation method and then enters an extraction process.

(4) Ball-milling the positive active material obtained in the step (3) to obtain positive active material powder, adding water into 100g of the positive active material powder to prepare slurry, placing the slurry into a closed reaction kettle, wherein the liquid-solid ratio is 5mL:1g, and introducing 240mL of SO at the temperature of 60 DEG C₂And (3) introducing compressed air to adjust the system pressure to be 0.3MPa, leaching for 2 hours, wherein the usage amount of sulfur dioxide is 4 times of the theoretical value, and the leaching rates of nickel, cobalt, manganese and lithium are respectively 99.53%, 99.36%, 99.28% and 99.79%.

Example 2

The embodiment provides a method for combined treatment of crude cobalt hydroxide and a waste ternary cathode, which comprises the following specific steps:

(1) adding the crude cobalt hydroxide into pure water for slurrying, wherein the liquid-solid ratio is 5mL:1 g; adding a proper amount of concentrated sulfuric acid to ensure that Co in acid leaching solution after acid leaching is contained²⁺＝64.9g/L，pH＝1.36。

(2) And (2) crushing the waste ternary positive plate into small pieces of 4-6cm, adding the small pieces into the pickle liquor obtained in the step (1), wherein the liquor-solid ratio is 20mL:1g, stirring, and carrying out ultrasonic cleaning and soaking for 50 min.

(3) The acid leaching solution is filtered for the first time to obtain a current collector (a massive aluminum foil), and then filtered for the second time to obtain the anode active material, so that complete separation can be realized. At this time, Co in the pickle liquor²⁺＝66.7g/L，Al³⁺The concentration is 118.6mg/L, pH is 1.86, and the pickle liquor can be subjected to chemical precipitation to remove aluminum and then enters the extraction process.

(4) Ball-milling the positive active material obtained in the step (3) to obtain positive active material powder, adding water into 100g of the positive active material powder to prepare slurry, placing the slurry into a closed reaction kettle, wherein the liquid-solid ratio is 5mL:1g, and introducing 120mL of SO at 60 DEG C₂And (3) introducing compressed air to adjust the system pressure to be 0.3MPa, leaching for 3h, wherein the use amount of sulfur dioxide is 2 times of the theoretical value, and the leaching rates of nickel, cobalt, manganese and lithium are respectively 98.26%, 96.22%, 97.93% and 99.03%.

Example 3

The embodiment provides a method for combined treatment of crude cobalt hydroxide and a waste ternary cathode, which comprises the following specific steps:

(1) adding the crude cobalt hydroxide into pure water for slurrying, wherein the liquid-solid ratio is 5mL:1 g; adding a proper amount of concentrated sulfuric acid to ensure that Co in acid leaching solution after acid leaching is contained²⁺＝66.7g/L，pH＝1.39。

(2) And (2) crushing the waste ternary positive plate into small pieces of 4-6cm, adding the small pieces into the pickle liquor obtained in the step (1), wherein the liquor-solid ratio is 10mL:1g, stirring, and soaking for 60min by ultrasonic cleaning.

(3) The acid leaching solution is filtered for the first time to obtain a current collector (a massive aluminum foil), and then filtered for the second time to obtain the anode active material, so that complete separation can be realized. At this time, Co in the pickle liquor²⁺＝73.5g/L，Al³⁺The concentration is 181.4mg/L, the pH value is 2.47, and the pickle liquor can be subjected to aluminum removal by a chemical precipitation method and then enters the extraction process.

(4) Ball-milling the positive active material obtained in the step (3) to obtain positive active material powder, adding water into 100g of the positive active material powder to prepare slurry, placing the slurry into a closed reaction kettle, wherein the liquid-solid ratio is 5mL:1g, and introducing 180mL of SO at 60 DEG C₂And (3) introducing compressed air to adjust the system pressure to be 0.3MPa, leaching for 3h, wherein the use amount of sulfur dioxide is 3 times of the theoretical value, and the leaching rates of nickel, cobalt, manganese and lithium are respectively 99.34%, 99.28%, 99.15% and 99.65%.

Comparative example 1

(1) The waste ternary positive plate is crushed into 4-6cm small pieces, added into 0.5mol/L sulfuric acid solution with the liquid-solid ratio of 15mL to 1g, stirred and soaked for 30min by ultrasonic cleaning.

(2) The acid leaching solution is filtered at the first stage to obtain a current collector (a massive aluminum foil), and then filtered at the second stage to obtain a positive active material, so that complete separation can be realized, part of the aluminum foil is corroded to form aluminum scraps to be mixed in the positive active material, and at the moment, Co in the acid leaching solution is mixed with Co in the positive active material²⁺＝4.73g/L，Al³⁺The concentration was 318.6mg/L, pH 1.54.

Comparing example 1 with comparative example 1, it can be seen that:

the crude cobaltous hydroxide acid immersion liquid is adopted to replace 0.5mol/L sulfuric acid solution to soak the waste ternary positive plate, the equal separation effect of the aluminum foil and the positive active material can be realized by properly prolonging the immersion time, but compared with dilute sulfuric acid immersion, less aluminum is leached from the solution, the leached cobalt is easy to recover, and basically no aluminum scraps are mixed in the separated positive active material.

Comparative example 2

(1) Adding the crude cobalt hydroxide into pure water for slurrying, wherein the liquid-solid ratio is 5mL:1 g; adding a proper amount of concentrated sulfuric acid to ensure that Co in acid leaching solution after acid leaching is contained²⁺＝64.9g/L，pH＝1.36。

(2) And (2) crushing the waste ternary positive plate into 4-6cm small pieces, adding the small pieces into the pickle liquor obtained in the step (1), wherein the liquor-solid ratio is 20mL:1g, stirring, and soaking for 40min by ultrasonic cleaning.

(3) The acid leaching solution is filtered for the first time to obtain a current collector (a massive aluminum foil), and then filtered for the second time to obtain the anode active material, so that complete separation can be realized. At this time, Co in the pickle liquor²⁺＝66.7g/L，Al³⁺The concentration is 118.6mg/L, pH is 1.86, and the pickle liquor can be subjected to chemical precipitation to remove aluminum and then enters the extraction process.

(4) Ball-milling the positive active material obtained in the step (3) to obtain positive active material powder, adding water to prepare slurry, placing the slurry into a closed reaction kettle, wherein the liquid-solid ratio is 5mL:1g, and introducing SO at 60 DEG C₂Reducing and leaching the gas, wherein the usage amount of sulfur dioxide is 1.5 times of the theoretical value, the leaching time is 4 hours, and the leaching rates of nickel, cobalt, manganese and lithium are respectively 95.28%, 95.25%, 95.08% and 97.66%.

Comparing example 2 with comparative example 2, it can be seen that:

the pressure leaching is adopted, the excess coefficient of sulfur dioxide is increased, the reaction time can be effectively shortened, and the leaching rate of valuable metals is improved.

Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.

Moreover, those skilled in the art will appreciate that while some embodiments herein include some features included in other embodiments, rather than other features, combinations of features of different embodiments are meant to be within the scope of the application and form different embodiments. For example, in the claims above, any of the claimed embodiments may be used in any combination. The information disclosed in this background section is only for enhancement of understanding of the general background of the application and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.