CN111994925A - Comprehensive utilization method of valuable resources in waste lithium batteries - Google Patents

Abstract

The invention discloses a comprehensive utilization method of valuable resources in waste lithium batteries, and relates to the technical field of lithium battery recycling. The method comprises: pretreatment steps, acid leaching steps, aluminum and iron removal steps, copper removal steps, and calcium magnesium lithium removal step, ternary precursor preparation step, chlorination step, iron removal step, magnesium calcium removal step, lithium precipitation step, in the calcium magnesium lithium removal step, by adding sodium fluoride, both calcium removal, magnesium removal and removal can be achieved. For the purpose of lithium, the separation of lithium ions from cobalt, nickel and manganese ions can be achieved at the same time; pure ternary precursors and battery-grade lithium carbonate can be prepared by this method, which is low in cost, simple in process and suitable for industrial production.

Description

A comprehensive utilization method of valuable resources in waste lithium batteries

technical field

The invention relates to the technical field of lithium battery recycling, in particular to a comprehensive utilization method for valuable resources in waste lithium batteries.

Background technique

Metal elements such as cobalt, manganese, nickel, and lithium are widely used in the field of lithium batteries. In particular, cobalt is an important strategic metal, but there is a serious shortage of cobalt mineral resources in my country, the consumption of cobalt is increasing year by year, and most of the cobalt raw materials are imported. The content of cobalt, nickel, manganese, and lithium in the cathode material of waste lithium batteries is also relatively high, which has high recycling value.

With the rapid development of the new energy vehicle industry, the output of ternary lithium batteries shows a trend of rapid increase, and the recycling of waste lithium batteries has become a research hotspot. At present, wet recycling technology is mainly used. In wet recycling technology, waste lithium batteries After discharge dismantling, crushing and screening, acid leaching, purification and impurity removal, etc., a mixed solution containing cobalt, nickel, manganese, and lithium is obtained. Because the mixed solution contains a large amount of impurity ions such as iron, magnesium, calcium, aluminum, copper, etc. , resulting in difficult separation of cobalt, nickel, manganese and lithium elements and low quality of the obtained products.

In the prior art, ion-exchange membranes are often used to separate solution ions, but the ion-exchange membranes have disadvantages such as poor mechanical properties, low separation efficiency, and easy contamination of the outer membrane. , The production cost is expensive. Therefore, how to recover valuable resources in waste lithium batteries and improve product quality has become an urgent problem to be solved.

SUMMARY OF THE INVENTION

In view of the fact that "the mixed solution containing cobalt, nickel, manganese and lithium contains a large amount of impurity ions such as iron, magnesium, calcium, aluminum and copper in the prior art, the separation of cobalt, nickel, manganese and lithium elements is difficult and the resulting products are difficult to separate. The technical problem of "low quality", the purpose of the present invention is to provide a comprehensive utilization method of valuable resources in waste lithium batteries with low cost and simple process, by which pure ternary precursors and battery-grade lithium carbonate can be prepared.

In order to achieve the above object, the present invention provides the following technical solutions:

The invention provides a comprehensive utilization method of valuable resources in waste lithium batteries, the method comprising:

In the pretreatment step, the waste lithium batteries are sequentially subjected to acid leaching and discharge, water washing, roasting, crushing and sieving;

In the acid leaching step, the powder containing nickel, cobalt, manganese and lithium is put into the leaching tank, and concentrated sulfuric acid and hydrogen peroxide are added into the leaching tank to perform intermittent leaching to obtain a mixed solution containing cobalt, nickel, manganese and lithium;

In the step of removing aluminum and iron, a set proportion of sodium carbonate is added to the mixed solution containing cobalt, nickel, manganese, and lithium for reaction, and aluminum and iron ions in the solution are removed. After solid-liquid separation, a mixed solution after removing aluminum and iron is obtained. ;

In the copper removal step, sodium sulfide in a stoichiometric ratio is added to the mixed solution after removing aluminum and iron to react to form copper sulfide precipitation, and after solid-liquid separation, the mixed solution after removing copper is obtained;

In the step of removing calcium, magnesium and lithium, sodium fluoride is added to the mixed solution after removing copper for reaction to generate calcium fluoride, magnesium fluoride and lithium fluoride sediment, and after solid-liquid separation, a mixed solution containing cobalt, nickel and manganese is obtained ;

In the preparation step of the ternary precursor, sodium hydroxide is added to the mixed solution containing cobalt, nickel and manganese, and the reaction is performed to obtain nickel cobalt manganese hydroxide precipitate;

In the chlorination step, calcium fluoride, magnesium fluoride and lithium fluoride sediment are added to hydrochloric acid for reaction, and after solid-liquid separation, a lithium-rich solution is obtained;

In the iron removal step, the lithium-rich solution is passed through a filtration device equipped with solid manganese dioxide, and Fe ²⁺ is converted into Fe ³⁺ , which is converted into hydroxide precipitation, evaporated and concentrated, and separated from solid and liquid to obtain a concentrated rich Lithium solution;

In the step of removing magnesium and calcium, sodium carbonate is added to the concentrated lithium-rich solution to remove most of the magnesium and calcium ions, and then a mixture of sodium hydroxide and sodium carbonate is added to further remove the remaining magnesium and calcium ions to obtain an impurity-removed rich solution. Lithium solution;

In the lithium precipitation step, sodium carbonate is added to the impurity-removed lithium-rich solution to precipitate lithium carbonate crystals, solid-liquid separation, and then flash drying to obtain battery-grade lithium carbonate.

In a preferred solution, the preprocessing steps are specifically:

(1) One acid leaching discharge: put the waste lithium battery into dilute sulfuric acid for discharge, the mass concentration of dilute sulfuric acid is 5% to 20%, and the discharge time is 2 to 6 hours;

(2) Secondary acid leaching discharge: put the waste lithium battery into dilute sulfuric acid for discharge, the mass concentration of dilute sulfuric acid is 10% to 30%, and the discharge time is 2 to 6h;

(3) Washing: put the waste lithium battery after two acid leaching discharges into the washing tank for washing;

(4) Roasting: the washed waste lithium battery is put into a steel belt furnace for roasting, and the roasted dilute sulfuric acid waste gas is introduced into an acid mist absorption tower for treatment and then discharged;

(5) Crushing and screening: crush the waste lithium battery after roasting by a hammer crusher, and then sieve it by a vibrating screen after crushing. Lithium powder.

In a preferred solution, in the acid leaching step, the reaction temperature is 60-70°C, the leaching liquid-solid ratio is 3-4:1, the initial leaching sulfuric acid concentration is 200-240 g/L, the leaching end point pH is 1-2, and the leaching solution Time 6 ~ 10h.

The powder containing nickel, cobalt, manganese, and lithium is leached with concentrated sulfuric acid to form soluble sulfate and enter the solution. By adding hydrogen peroxide, the leaching of nickel, cobalt, manganese, and lithium is promoted. The main reaction equations involved are as follows:

MeO+H ₂ SO ₄ →MeSO ₄ +H ₂ O (Me is Ni, Co, Mn, Cu, Ca, Mg, Fe, etc.)

2LiCoO ₂ +3H ₂ SO ₄ +H ₂ O ₂ →Li ₂ SO ₄ +2CoSO ₄ +O ₂ ↑+4H ₂ O

2LiNiO ₂ +3H ₂ SO ₄ +H ₂ O ₂ →Li ₂ SO ₄ +2NiSO ₄ +O ₂ ↑+4H ₂ O

2LiMnO ₂ +3H ₂ SO ₄ +H ₂ O ₂ →Li ₂ SO ₄ +2MnSO ₄ +O ₂ ↑+4H ₂ O

2Fe ²⁺ +H ₂ O ₂ +2H ⁺ →2Fe ³⁺ +2H ₂ O

In a preferred solution, in the step of removing aluminum and iron, high-temperature steam is added, the reaction temperature is controlled to be >90°C, and the reaction time is 1-4 hours.

In the step of removing aluminum and iron, sodium carbonate is added to the mixed solution containing cobalt, nickel, manganese, and lithium for reaction, and the pH value of the control solution is 4.5, so that aluminum and sodium carbonate react to generate aluminum slag (aluminum carbonate is decomposed into hydrogen when meeting water). Alumina), Fe ³⁺ is hydrolyzed to form ferric hydride precipitation. After the solid-liquid separation by the filter press, the remaining materials no longer contain aluminum and iron, so as to achieve the purpose of removing aluminum and iron. The main reaction equations involved are as follows:

2Al ³⁺ +3Na ₂ CO ₃ =Al ₂ (CO ₃ ) ₃ +6Na ⁺

Al ₂ (CO ₃ ) ₃ +3H ₂ O=2Al(OH) ₃ ↓+3CO ₂ ↑

H ₂ SO ₄ +Na ₂ CO ₃ =Na ₂ SO ₄ +H ₂ O+3CO ₂ ↑

Fe ³⁺ +3H ₂ O→Fe(OH) ₃ ↓+3H ⁺

In the step of removing calcium, magnesium and lithium, by adding sodium fluoride, the purpose of removing calcium, magnesium and lithium can be achieved, and at the same time, the separation of lithium ions from cobalt, nickel and manganese ions can be achieved.

In a preferred solution, in the chlorination step, calcium fluoride, magnesium fluoride and lithium fluoride precipitates are added to hydrochloric acid for reaction, and the reaction time is 1 to 4 hours, and calcium fluoride and magnesium fluoride precipitates do not react with hydrochloric acid. The main reaction equations involved are as follows:

LiF+HCl=LiCl+HF(aq)

In the iron removal step, manganese dioxide is a good catalyst for the conversion of Fe ²⁺ to Fe ³⁺ , and the generated Fe ³⁺ is hydrolyzed to form Fe(OH) ₃ precipitation, which is immediately removed by the filtration device. The main reaction equations involved are as follows:

4H ⁺ +2Fe ²⁺ +MnO ₂ →Mn ²⁺ +2Fe ³⁺ +2H ₂ O

In the step of removing magnesium and calcium, according to the amount of magnesium and calcium ions in the lithium-rich solution, a stoichiometric amount of sodium carbonate is added, and after sufficient reaction, the precipitate is filtered off to remove most of the magnesium and calcium ions; The pH of the mixture is adjusted to be 13, the mass concentration of sodium hydroxide is 10%-20%, and the mass concentration of sodium carbonate is 40%-60%, and the remaining magnesium and calcium ions are further removed. The main reaction equations involved are as follows:

CO ₃ ^2- +Ca ²⁺ →CaCO ₃ ↓

CO ₃ ^2- +Mg ²⁺ →MgCO ₃ ↓

2OH ^- +Mg ²⁺ →Mg(OH) ₂ ↓

Since the solubility product K _SP of LiCO ₃ is 8.15×10 ^-4 , the solubility product K _SP of CaCO ₃ is 3.36×10 ^-9 , and the solubility product K _SP of MgCO ₃ is 6.82×10 ^-6 . Stoichiometric amount of sodium carbonate was added to the solution, and no lithium carbonate would be precipitated; since the solubility product K _SP of Mg(OH) ₂ was 1.8×10 ^-11 , sodium hydroxide was added to deeply remove magnesium ions.

In a preferred solution, in the lithium precipitation step, sodium carbonate is added to the lithium-rich solution after impurity removal, the reaction temperature is 45-60° C., and the reaction time is 1-4 hours. The main reaction equations involved are as follows:

2LiCl+2NaCO ₃ +2HF→Li ₂ CO ₃ ↓+NaF+HCl+CO ₂ ↑

The preferred scheme, in the flash drying step, after the lithium carbonate crystallization is filtered, flash drying is performed, and the crystallization temperature of lithium carbonate is >100 ° C, and finally the lithium carbonate product is obtained, and the filtrate is sent to the sewage treatment station for treatment.

Compared with the prior art, the beneficial technical effects of the present invention:

The invention provides a comprehensive utilization method of valuable resources in waste lithium batteries. The method can prepare pure ternary precursor and battery-grade lithium carbonate. The method has low cost, simple process and is suitable for industrial production.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without any creative effort.

1 is a process flow diagram of a comprehensive utilization method for valuable resources in waste lithium batteries of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, ordinary skills in the art All other embodiments obtained by personnel without creative work fall within the protection scope of the present invention.

The experimental methods described in the following examples are conventional methods unless otherwise specified, and the reagents and materials can be obtained from commercial sources unless otherwise specified.

Example 1

The present embodiment is a comprehensive utilization method for valuable resources in waste lithium batteries, characterized in that the method includes:

(1) The waste ternary nickel-cobalt-manganese 18650 lithium battery is subjected to acid leaching discharge, water washing, roasting, crushing and sieving in turn. The objects on the sieve are steel shells, aluminum foil and copper sheets, and the objects under the sieve are nickel-cobalt-manganese-lithium-containing Powder, specifically:

(1.1) One acid leaching discharge: use a monorail crane to put the titanium basket containing the spent lithium battery into a dilute acid soaking tank (4m ³ ) with a dilute sulfuric acid concentration of about 8%, and the acid leaching discharge is about 4 hours;

(1.2) Secondary acid leaching discharge: use a monorail crane to put the titanium basket with the waste lithium battery into a dilute acid soaking tank (4m ³ ) with a dilute sulfuric acid concentration of about 14%, and the acid leaching discharge is about 4 hours;

(1.3) Washing: put the waste lithium battery after two acid leaching discharges into the washing tank for washing;

(1.4) Roasting: the washed waste lithium battery is put into the steel belt furnace for roasting, and the roasted dilute sulfuric acid waste gas is introduced into the acid mist absorption tower for treatment and then discharged;

(1.5) Crushing and screening: The waste lithium battery after roasting is crushed by a hammer crusher, and after crushing, it is screened by a vibrating screen. The material on the screen is steel shell, aluminum foil and copper sheet, and the material under the screen is nickel-cobalt-manganese-containing Lithium powder;

(2) acid leaching step, the powder containing nickel, cobalt, manganese and lithium is put into the leaching tank, and concentrated sulfuric acid and hydrogen peroxide are added to the leaching tank for intermittent leaching. The concentration of sulfuric acid is 220g/L, the pH value of the leaching end point is 1.5, and the leaching time is 8h to obtain a mixed solution containing cobalt, nickel, manganese and lithium;

(3) step of removing aluminum and iron, adding sodium carbonate to the mixed solution containing cobalt, nickel, manganese and lithium for reaction, controlling the pH value of the solution to be 4.5, adding 0.5MPa fresh steam, controlling the reaction temperature > 90 ℃, the reaction time 2h, after solid-liquid separation, the mixed solution after removing aluminum and iron is obtained;

(4) copper removal step, adding the sodium sulfide of stoichiometric ratio to the mixed solution after removing aluminum and iron, the reaction generates copper sulfide precipitation, and after solid-liquid separation, the mixed solution after removing copper is obtained;

(5) step of removing calcium, magnesium and lithium, adding sodium fluoride to the mixed solution after removing copper to react to generate calcium fluoride, magnesium fluoride and lithium fluoride sediment, and after solid-liquid separation, obtain cobalt, nickel, manganese containing The mixed solution; the slag washing water in this step uses pure water, and the slag washing water is reused in the process of removing aluminum and iron, and is not discharged;

(6) the ternary precursor preparation step, adding sodium hydroxide to the mixed solution containing cobalt, nickel and manganese, and reacting to obtain nickel cobalt manganese hydroxide precipitation, which can be directly used as the ternary precursor material;

(7) chlorination step, calcium fluoride, magnesium fluoride and lithium fluoride sediments are added to hydrochloric acid, and the reaction is carried out for 2h, and after solid-liquid separation, a lithium-rich solution is obtained;

(8) iron removal step, the lithium-rich solution is passed through the filtration device equipped with solid manganese dioxide, Fe ²⁺ is converted into Fe ³⁺ , and it is converted into hydroxide precipitation, evaporated and concentrated, and solid-liquid separation is obtained to obtain concentrated After the lithium-rich solution;

(9) step of removing magnesium and calcium, adding the mixture of sodium hydroxide and sodium carbonate to adjust the pH of the lithium-rich solution is 13, the mass concentration of sodium hydroxide is 15%, and the mass concentration of sodium carbonate is 50%, obtains the Lithium-rich solution;

(10) Lithium precipitation step, adding sodium carbonate to the lithium-rich solution after removal of impurities, the reaction temperature is 50°C, and the time is 2h, lithium carbonate crystals are precipitated, solid-liquid separation is performed, and then flash drying is performed to obtain battery-grade lithium carbonate .

In the lithium carbonate product obtained in Example 1, the purity of the lithium carbonate product is 99.8wt%, the content of magnesium is 0.004wt%, the content of calcium is 0.002wt%, the content of iron is 0.0006wt%, and the content of copper is 0.0002wt% , the content of aluminum is 0.0006wt%.

Example 2

The present embodiment is a comprehensive utilization method for valuable resources in waste lithium batteries, characterized in that the method includes:

(1) The waste ternary nickel-cobalt-manganese 18650 lithium battery is subjected to acid leaching discharge, water washing, roasting, crushing and sieving in turn. The objects on the sieve are steel shells, aluminum foil and copper sheets, and the objects under the sieve are nickel-cobalt-manganese-lithium-containing Powder, specifically:

(1.1) One acid leaching discharge: use a monorail crane to put the titanium basket with the waste lithium battery into a dilute acid soaking tank (4m ³ ) with a dilute sulfuric acid concentration of about 6%, and the acid leaching discharge is about 5h;

(1.2) Secondary acid leaching discharge: use a monorail crane to put the titanium basket with the waste lithium battery into the dilute acid soaking tank (4m ³ ) with a dilute sulfuric acid concentration of about 20%, and the acid leaching discharge is about 3h;

(1.3) Washing: put the waste lithium battery after two acid leaching discharges into the washing tank for washing;

(1.4) Roasting: the washed waste lithium battery is put into the steel belt furnace for roasting, and the roasted dilute sulfuric acid waste gas is introduced into the acid mist absorption tower for treatment and then discharged;

(1.5) Crushing and screening: The waste lithium battery after roasting is crushed by a hammer crusher, and after crushing, it is screened by a vibrating screen. The material on the screen is steel shell, aluminum foil and copper sheet, and the material under the screen is nickel-cobalt-manganese-containing Lithium powder;

(2) acid leaching step, the powder containing nickel, cobalt, manganese and lithium is put into the leaching tank, and concentrated sulfuric acid and hydrogen peroxide are added to the leaching tank for intermittent leaching. The concentration of sulfuric acid is 240g/L, the pH value of the leaching end point is 1.5, and the leaching time is 6h to obtain a mixed solution containing cobalt, nickel, manganese and lithium;

(3) step of removing aluminum and iron, adding sodium carbonate to the mixed solution containing cobalt, nickel, manganese and lithium for reaction, controlling the pH value of the solution to be 4.5, adding 0.5MPa fresh steam, controlling the reaction temperature > 90 ℃, the reaction time 3h, after solid-liquid separation, the mixed solution after removing aluminum and iron is obtained;

(4) copper removal step, adding the sodium sulfide of stoichiometric ratio to the mixed solution after removing aluminum and iron, the reaction generates copper sulfide precipitation, and after solid-liquid separation, the mixed solution after removing copper is obtained;

(5) step of removing calcium, magnesium and lithium, adding sodium fluoride to the mixed solution after removing copper to react to generate calcium fluoride, magnesium fluoride and lithium fluoride sediment, and after solid-liquid separation, obtain cobalt, nickel, manganese containing The mixed solution; the slag washing water in this step uses pure water, and the slag washing water is reused in the process of removing aluminum and iron, and is not discharged;

(6) the ternary precursor preparation step, adding sodium hydroxide to the mixed solution containing cobalt, nickel and manganese, and reacting to obtain nickel cobalt manganese hydroxide precipitation, which can be directly used as the ternary precursor material;

(7) chlorination step, calcium fluoride, magnesium fluoride and lithium fluoride sediments are added to hydrochloric acid, and the reaction is carried out for 2h, and after solid-liquid separation, a lithium-rich solution is obtained;

(8) iron removal step, the lithium-rich solution is passed through the filtration device equipped with solid manganese dioxide, Fe ²⁺ is converted into Fe ³⁺ , and it is converted into hydroxide precipitation, evaporated and concentrated, and solid-liquid separation is obtained to obtain concentrated After the lithium-rich solution;

(9) step of removing magnesium and calcium, adding the mixture of sodium hydroxide and sodium carbonate to adjust the pH of the lithium-rich solution is 13, the mass concentration of sodium hydroxide is 15%, and the mass concentration of sodium carbonate is 45%, obtains the Lithium-rich solution;

(10) Lithium precipitation step, adding sodium carbonate to the lithium-rich solution after removal of impurities, the reaction temperature is 50°C, and the time is 2h, lithium carbonate crystals are precipitated, solid-liquid separation is performed, and then flash drying is performed to obtain battery-grade lithium carbonate .

In the lithium carbonate product obtained in Example 2, the purity of the lithium carbonate product is 99.7wt%, the content of magnesium is 0.005wt%, the content of calcium is 0.003wt%, the content of iron is 0.0008wt%, and the content of copper is 0.0003wt% , the content of aluminum is 0.0005wt%.

The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. For those skilled in the art, improvements and transformations obtained without departing from the technical concept of the present invention should also be regarded as the protection scope of the present invention.

Claims (10)

1. A comprehensive utilization method of valuable resources in waste lithium batteries is characterized by comprising the following steps:

the method comprises the following steps of pretreatment, namely, carrying out acid leaching discharge, water washing, roasting, crushing and screening on waste lithium batteries in sequence, wherein oversize products comprise a steel shell, an aluminum foil and a copper sheet, and undersize products comprise powder containing nickel, cobalt, manganese and lithium;

acid leaching, namely putting powder containing nickel, cobalt, manganese and lithium into a leaching tank, and adding concentrated sulfuric acid and hydrogen peroxide into the leaching tank to perform discontinuous leaching to obtain a mixed solution containing cobalt, nickel, manganese and lithium;

removing aluminum and iron, namely adding sodium carbonate with a set proportion into a mixed solution containing cobalt, nickel, manganese and lithium to react, removing aluminum and iron ions in the solution, and performing solid-liquid separation to obtain a mixed solution after aluminum and iron removal;

a copper removing step, namely adding sodium sulfide in a stoichiometric ratio into the mixed solution after aluminum and iron removal, reacting to generate copper sulfide precipitate, and performing solid-liquid separation to obtain the mixed solution after copper removal;

removing calcium, magnesium and lithium, namely adding sodium fluoride into the mixed solution after copper removal to react to generate calcium fluoride, magnesium fluoride and lithium fluoride sediments, and performing solid-liquid separation to obtain a mixed solution containing cobalt, nickel and manganese;

a step of preparing a ternary precursor, which is to add sodium hydroxide into a mixed solution containing cobalt, nickel and manganese to react to obtain a nickel-cobalt-manganese hydroxide precipitate;

chlorination, namely adding calcium fluoride, magnesium fluoride and lithium fluoride sediments into hydrochloric acid for reaction, and performing solid-liquid separation to obtain a lithium-rich solution;

a step of removing iron, namely, passing the lithium-rich solution through a filter device filled with solid manganese dioxide to remove Fe²⁺Conversion to Fe³⁺Converting the lithium-rich solution into hydroxide precipitate, evaporating and concentrating, and carrying out solid-liquid separation to obtain a concentrated lithium-rich solution;

removing magnesium and calcium, namely adding sodium carbonate into the concentrated lithium-rich solution to remove most of magnesium and calcium ions, then adding a mixture of sodium hydroxide and sodium carbonate to further remove the rest of magnesium and calcium ions to obtain the lithium-rich solution after impurity removal;

and a lithium precipitation step, namely adding sodium carbonate into the lithium-rich solution after impurity removal, separating lithium carbonate crystals, carrying out solid-liquid separation, and then carrying out flash evaporation drying to obtain the battery-grade lithium carbonate.

2. The method for comprehensively utilizing valuable resources in the waste lithium batteries as claimed in claim 1, wherein the pretreatment step specifically comprises:

(1) primary acid leaching discharge: putting the waste lithium battery into dilute sulfuric acid for discharging, wherein the mass concentration of the dilute sulfuric acid is 5-20%, and the discharging time is 2-6 h;

(2) secondary acid leaching discharge: putting the waste lithium battery into dilute sulfuric acid for discharging, wherein the mass concentration of the dilute sulfuric acid is 10% -30%, and the discharging time is 2-6 h;

(3) washing with water: putting the waste lithium battery subjected to acid leaching discharge twice into a washing tank for washing;

(4) roasting: putting the washed waste lithium battery into a steel belt furnace for roasting, introducing the roasted dilute sulfuric acid waste gas into an acid mist absorption tower for treatment, and then discharging;

(5) crushing and screening: crushing the roasted waste lithium battery by a hammer crusher, screening by a vibrating screen after crushing, wherein oversize materials comprise a steel shell, an aluminum foil and a copper sheet, and undersize materials comprise powder containing nickel, cobalt, manganese and lithium.

3. The method for comprehensively utilizing valuable resources in the waste lithium batteries according to claim 1, wherein in the acid leaching step, the reaction temperature is 60-70 ℃, and the solid-to-solid ratio of a leaching solution is 3-4: 1, the concentration of initial sulfuric acid for leaching is 200-240 g/L, the pH value of a leaching end point is 1-2, and the leaching time is 6-10 h.

4. The method for comprehensively utilizing valuable resources in the waste lithium batteries as claimed in claim 1, wherein in the step of removing aluminum and iron, high-temperature steam is added, the reaction temperature is controlled to be more than 90 ℃, and the reaction time is 1-4 h.

5. The method for comprehensively utilizing valuable resources in the waste lithium batteries as claimed in claim 1, wherein in the chlorination step, calcium fluoride, magnesium fluoride and lithium fluoride sediments are added into hydrochloric acid for reaction for 1-4 h.

6. The method for comprehensively utilizing valuable resources in the waste lithium batteries as claimed in claim 1, wherein in the step of removing magnesium and calcium, stoichiometric sodium carbonate is added according to the amount of magnesium and calcium ions in the lithium-rich solution, and after full reaction, the precipitate is filtered out to remove most of the magnesium and calcium ions; and adding a mixture of sodium hydroxide and sodium carbonate to adjust the pH value of the lithium-rich solution to 13, wherein the mass concentration of the sodium hydroxide is 10-20%, and the mass concentration of the sodium carbonate is 40-60%.

7. The comprehensive utilization method of valuable resources in the waste lithium batteries as claimed in claim 1, wherein in the step of depositing lithium, the reaction temperature is 45-60 ℃ and the reaction time is 1-4 h.

8. The method for comprehensively utilizing valuable resources in the waste lithium batteries as claimed in claim 1, wherein flash evaporation drying is performed after lithium carbonate crystallization and filtration, the crystallization temperature of lithium carbonate is greater than 100 ℃, finally a lithium carbonate product is obtained, and the filtrate is sent to a sewage treatment station for treatment.

9. A nickel cobalt manganese hydroxide product obtainable by the process of any one of claims 1 to 8.

10. A battery grade lithium carbonate product, characterised in that it is produced by the process of any one of claims 1 to 8.

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