WO2018192121A1 - Method for efficiently recovering positive electrode material precursor and lithium carbonate from positive electrode waste material of lithium ion battery - Google Patents

Abstract

A method for recovering a positive electrode material precursor and lithium carbonate from a positive electrode waste material of a lithium ion battery. The waste material is a positive electrode powder material containing impurities which is generated during battery production or obtained from waste batteries by means of mechanical crushing and sorting. The method comprises: carrying out leaching by using a volatile leaching agent containing a reducing agent to obtain a leachate; carrying out concentration rectification, and regenerating the volatile leaching agent; adjusting ingredients of the raffinate containing Co, Ni, Mn and Li, and carrying out coprecipitation on Co, Ni and Mn components; carrying out solid-liquid separation; and further treating the Li-rich solution to obtain high-purity lithium carbonate, and carrying out a high-temperature solid-phase reaction on the mixed material used for preparing Co, Ni and Mn precursors to obtain a positive electrode active material. The method has a simple flow and does not need a complicated impurity removal step and an extraction and enrichment process. In addition, the leaching agent may come from a wide range of sources, has high leaching selectivity and high leaching rate, and can be recycled after a leaching reaction by means of concentration rectification. Thus, the cost is reduced, and high-quality Co, Ni and Mn precursors and high-purity lithium carbonate can be obtained. The method has a good application prospect.

Description

Method for efficiently recovering positive electrode material precursor and lithium carbonate from cathode waste material of lithium ion battery Technical field

The invention belongs to the technical field of secondary resource recycling and recycling economy, and particularly relates to a method for efficiently recovering a positive electrode material precursor and lithium carbonate from a lithium ion battery positive electrode waste.

Background technique

Lithium-ion batteries have many advantages such as high energy density, small self-discharge, excellent cycle performance, high charging efficiency, no memory effect, etc., and are widely used in various consumer electronic products, military, pure electric vehicles and aerospace applications. With the development of electric vehicles, the future power lithium-ion batteries will usher in a huge market, and there will be a problem of recycling and recycling of a large number of power lithium-ion batteries. With the upcoming peak of power battery scrapping, the recycling scale of used lithium-ion batteries will grow rapidly, and the market value of used battery recycling will be even greater.

At present, researchers at home and abroad have conducted a lot of research and discussion on the treatment and recycling of waste lithium-ion batteries. The hydrometallurgical treatment method has the advantages of high recovery efficiency, simple process, easy process control, etc. attention. At present, the mainstream recycling process can be divided into two types: step-by-step recycling and collaborative recycling. The first type is based on a step-by-step recovery method to obtain elements such as lithium, cobalt, nickel, manganese, and the like, respectively. For example, CN105331819A discloses a method for recovering Co ₃ O ₄ from a cathode material of a waste lithium cobalt oxide battery, and the separation and recovery of cobalt elements are achieved by organic acid leaching and organic extraction. CN101280357A reports multi-stage acid leaching extraction using a sulfuric acid/hydrogen peroxide mixed solution, and finally recovers cobalt oxalate and lithium carbonate separately. CN104241724A discloses a method for recovering lithium carbonate from a spent lithium ion battery, in which other valuable elements are converted into impurities as impurities. CN104124487A discloses a method for fractionally recovering cobalt, copper, aluminum and lithium in a waste lithium ion battery by using a liquid phase reaction. The method integrates alkali leaching, acid leaching, and agent extraction to achieve full component recovery of valuable elements in the battery. The second type is a process for preparing a precursor of a positive electrode material in one step, such as nickel, cobalt, and manganese. For example, CN102676827A discloses a method for recovering valuable metals from a nickel-cobalt-manganese lithium battery, separating the positive electrode material and the battery powder by solvent sonication and filtration, and then using acid leaching oxidation, adjusting the pH of the alkali solution, etc. to obtain nickel-cobalt-manganese composite carbonic acid. salt. Similarly, CN105048020A discloses a method for preparing a lithium-doped cobalt ferrite material from a waste lithium battery, and finally obtains a cobalt ferrite material by acid leaching and high temperature baking in a microwave oven. CN103199230A discloses a process for reversely recovering lithium nickel manganese oxide from a waste lithium battery as a raw material, obtaining nickel manganese oxide by using an acetate complexing agent and electrolysis, and calcining it with a lithium source to obtain lithium nickel manganese oxide. CN103400965A uses a process similar to the patent CN103199230A to prepare lithium nickel cobaltate by reverse recovery from a waste lithium ion battery. CN102751549A utilizes a method of leaching of a fluorine-containing organic acid to realize preparation of a ternary precursor of nickel, cobalt and manganese and recovery of lithium carbonate.

The prior art mainly relies on acid-base leaching, organic acid leaching/extraction, etc. to recover valuable elements in the used batteries by the above-mentioned step-by-step acquisition or synergistic recovery. However, the selective leaching effect of the leaching agent is not obvious. The leaching solution often contains a large amount of impurity elements, resulting in a large consumption of the leaching agent. At the same time, the purity of the obtained product is poor, especially the recovery and purification of lithium is relatively difficult, the impurity removal step is complicated, and the cost is complicated. At the same time, the recycling of the leaching agent has not been reported.

Summary of the invention

In view of the deficiencies of the existing waste lithium ion battery recycling technology, such as complicated recycling process, low recovery efficiency, high cost, difficulty in comprehensive recovery of valuable metals, and non-recycling of leaching agent, the present invention aims to provide a simple and efficient method. A method for recovering and preparing a Co, Ni, Mn precursor and lithium carbonate, wherein the method adopts a strong leaching ability of a leaching agent, a high leaching rate (greater than 90%), and a leaching agent is recycled by a concentrated distillation cycle . The invention has simple process, no complicated impurity removal step and extraction enrichment, strong operability, low equipment requirement and low processing cost, and can obtain high purity Co, Ni, Mn precursor and lithium carbonate (purity >99.9%). Has a good application prospects.

To this end, the present invention employs the following technical solutions:

A method for recovering a positive electrode material precursor and lithium carbonate from a positive electrode waste of a lithium ion battery, wherein the waste material is an impurity-containing positive electrode powder obtained by mechanically crushing and sorting the powder or waste battery obtained by removing the positive electrode sheet in the production waste. Material, including the following steps:

(1) leaching the lithium ion battery positive waste material with a volatile leaching agent containing a reducing agent, and separating the leaching liquid and the leaching slag;

(2) The leaching solution obtained in the step (1) is subjected to concentrated rectification, and the leaching agent is regenerated to obtain a volatile leaching agent and a residual liquid containing Co, Ni, Mn and Li;

(3) The residual liquid obtained in the step (2) is subjected to co-precipitation of Co, Ni, and Mn components after being controlled by components;

(4) Step (3) After the coprecipitation is completed, solid-liquid separation is performed to obtain a lithium-rich solution and a mixture for preparing a Co, Ni, Mn precursor;

(5) The Co, Ni, Mn mixture obtained in the step (4) is prepared by a high temperature solid phase reaction to prepare a positive electrode material active material. The obtained lithium-rich solution was added to a saturated sodium carbonate solution to obtain a white precipitate. After suction filtration, washing and drying, a high-purity lithium carbonate solid was obtained.

The leaching agent according to the step (1) is a solution in which one or more kinds of volatile organic and/or inorganic acids are mixed and mixed with one or more reducing agents;

The acid concentration is 0.1-15 mol/L, the mass percentage of the reducing agent is 0.1-20%, the leaching S/L ratio is 5-500 g/L, the leaching temperature is 5-100 ° C, and the leaching time is 5-480 min. The stirring speed is 0 to 2000 rpm.

The acid concentration is optimized to be 2 to 4 mol/L;

The volatile acid is optimized to be one or a mixture of sulfuric acid, hydrochloric acid, nitric acid, trichloroacetic acid, trifluoroacetic acid, citric acid, formic acid, acetic acid;

Preferably, the reducing agent has a mass percentage of 2 to 8%;

Preferably, the reducing agent is one or a combination of sodium sulfite, sulfurous acid, sodium thiosulfate or hydrogen peroxide;

Preferably, the leaching S/L is 80-150 g/L;

Preferably, the leaching temperature is 20 to 80 ° C;

Preferably, the stirring speed is 100 to 500 rpm.

The residual liquid obtained in the step (3) is subjected to co-precipitation of the Co, Ni, and Mn components by the component control, and the lithium-rich solution and the mixture for preparing the Co, Ni, and Mn precursors are obtained by solid-liquid separation.

When the composition is adjusted, the molar ratio of nickel, cobalt and manganese in the solution containing nickel and cobalt is adjusted to conform to the molar ratio of Ni, Co and Mn in the molecular formula LiNi _x Co _y Mn _1-xy O ₂ , wherein x >0, y>0, and x+y<1.

The molar ratio of nickel, cobalt and manganese in the solution containing nickel and cobalt is specifically: adding one or at least two of a water-soluble nickel salt, a cobalt salt or a manganese salt to a solution containing nickel, cobalt and manganese. combination.

The pH of the solution during the coprecipitation is 7-12, the solution for adjusting the pH is an alkaline solution, the concentration of the alkali solution is 0.1-10 mol/L, the stirring speed is 0-2000 rpm, the stirring adjustment time is 0.5-72 h, and the pH is adjusted. The temperature is 5 to 95 ° C;

Preferably, the alkaline solution is a mixture of one or both of sodium hydroxide and aqueous ammonia.

The pH of the coprecipitation solution is optimized to be 10 to 11; the alkali concentration is optimized to be 2 to 4 mol/L; the stirring speed is optimized to be 100 to 500 rpm; the stirring adjustment time is optimized to be 2 to 4 hours; Temperature Optimized to 20 to 50 ° C.

Step (4) after the completion of the coprecipitation, solid-liquid separation is performed to obtain a lithium-rich solution and a mixture for preparing a Co, Ni, and Mn precursor;

Preferably, the solid-liquid separation is achieved by suction filtration or filtration.

The Co, Ni, Mn precursor mixture obtained in the step (5) is prepared by a high temperature solid phase reaction to prepare a cathode active material;

The obtained lithium-rich solution is subjected to high-temperature concentration/rectification treatment, and a saturated sodium carbonate solution is added to obtain a white precipitate. After suction filtration, washing and drying, a high-purity lithium carbonate solid is obtained;

Wherein, the precipitation temperature of lithium carbonate is 20-100 ° C, the stirring speed of lithium carbonate precipitation is 0-2000 rpm, the adjustment time of precipitation stirring is 0.5-72 h, and the temperature of washing water is 10-100 ° C;

Preferably, the high temperature solid phase reaction temperature is 600 to 850 ° C, and the reaction time is 3 to 20 h;

Preferably, the lithium carbonate precipitation temperature is 60 to 100 ° C;

Preferably, the lithium carbonate precipitation stirring speed is 100 to 500 rpm;

Preferably, the lithium carbonate precipitation stirring adjustment time is 1 to 16 h;

Preferably, the molar ratio of the carbonate ion added to the lithium carbonate to the lithium ion in the solution is from 1 to 3:2; preferably, the temperature of the washing water is from 90 to 100 °C.

Compared with the prior art, the present invention has the following significant advantages:

(1) The volatile leaching agent of the invention has a wide source range, low raw material price, and can selectively extract valuable elements such as Co, Ni, Mn and Li element, thereby avoiding complicated impurity removal steps and extraction processes, and separating the obtained The leachate can directly obtain the Co, Ni, Mn precursor mixture by coprecipitation, and the process is simple;

(2) Since the leaching agent of the present invention does not leaching impurity elements such as Fe and Al, the leaching agent consumption is small in the production process, and the leaching agent is regenerated rapidly by concentrated rectification in a short-range, thereby further reducing the raw material cost and avoiding secondary pollution;

(3) The precursor product and the lithium carbonate product obtained by the present invention have a small impurity content, and can prepare high-purity lithium carbonate (purity >99.9%).

DRAWINGS

1 is a flow chart of a process for efficiently recovering a precursor of a positive electrode material and lithium carbonate from a positive electrode waste of a lithium ion battery according to the present invention.

detailed description

The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood by those skilled in the art that the described embodiments are only to be construed as illustrative and not restrictive.

A method for efficiently recovering a positive electrode material precursor and lithium carbonate from a lithium ion battery positive electrode waste, as shown in FIG. 1, the preferred process includes the following steps:

(1) The lithium ion battery positive electrode waste is leached with a volatile leaching agent containing a reducing agent, and the leaching liquid and the leaching slag are separated. The leaching agent is one or more of a volatile organic and/or inorganic acid, such as an organic and/or inorganic acid such as sulfuric acid, hydrochloric acid, nitric acid, trichloroacetic acid, trifluoroacetic acid, citric acid, formic acid or acetic acid. One or several blends. The acid concentration is 2 to 4 mol/L, and the mixed mass percentage is 2 to 8% of sodium sulfite, sulfurous acid, sodium thiosulfate or hydrogen peroxide as a reducing agent. The leaching S/L is 8 to 150 g/L, the leaching temperature is 20 to 80 ° C, the leaching time is 5 to 480 min, and the stirring speed is 100 to 500 rpm;

(2) The obtained leachate is subjected to high-temperature concentration/rectification treatment to recover the volatile leaching agent to obtain a residual liquid containing Co, Ni, Mn and Li;

(3) Co-precipitation of Co, Ni, and Mn components is carried out after the composition of Co, Ni, Mn, and Li is controlled by components. When adjusting the composition, the molar ratio of nickel, cobalt and manganese in the solution containing nickel and cobalt should be adjusted to match the molar ratio of Ni, Co and Mn in the formula LiNi _x Co _y Mn _1-xy O ₂ , where x>0 , y>0, and x+y<1. The obtained Co, Ni, Mn precursor mixture was prepared by a high temperature solid phase reaction method to prepare a positive electrode active material. The pH of the solution during coprecipitation is 10-11, and the solution for adjusting the pH is an alkaline solution, such as one or a mixture of sodium hydroxide and ammonia water, the concentration of the alkali solution is 2 to 4 mol/L, and the precipitation stirring speed is 100～500rpm, time is 2～4h, and the precipitation temperature is 20～50°C;

(4) After co-precipitation, solid-liquid separation is carried out by suction filtration or filtration to obtain a lithium-rich solution and a mixture for preparing a Co, Ni, Mn precursor;

(5) The positive electrode active material is prepared by high temperature solid phase reaction of Co, Ni, Mn mixture. The solid temperature reaction temperature is 800-850 ° C and the reaction time is 15-20 h. The lithium-rich solution is added to a saturated sodium carbonate solution to obtain a white precipitate. After suction filtration, washing, and drying, a high-purity lithium carbonate solid is obtained. The precipitation temperature of lithium carbonate is 20-90 ° C, the stirring speed of precipitation is 100-500 rpm, the adjustment time of precipitation stirring is 1-16 h, and the molar ratio of carbonate ion added by lithium carbonate precipitation to lithium ion in solution is 1-3:2. The temperature of the water used for washing is 90 to 100 °C.

Example

Part of the embodiments of the present invention, but not all of the embodiments, based on the embodiments of the present invention, the skill All other embodiments obtained by a person skilled in the art without innovating labor are within the scope of the invention.

Example 1

The lithium ion battery positive electrode waste was leached with a mixed acid of nitric acid and citric acid containing a hydrogen peroxide reducing agent (acid concentration of 2 mol/L, and a mass percentage of the reducing agent of 3%). The leaching S/L was 50 g/L, the leaching temperature was 40 ° C, the leaching time was 200 min, and the stirring speed was 150 rpm. A leachate containing Li, Ni, Co, and Mn and a leach residue were obtained. The leaching rates of the metals Li, Ni, Co and Mn were 92.21%, 90.60% and 91.20% and 92.5%, respectively, while the leaching rates of metal Al and Fe were only 1.32% and 2.76%. The leachate is subjected to high-temperature concentration/rectification treatment to recover the volatile leaching agent to obtain a residual liquid containing Co, Ni, Mn and Li. The distillation/concentration temperature was 200 ° C, the time was 30 min, and the stirring speed was 150 rpm. The molar ratio of nickel, cobalt and manganese in the solution containing Co, Ni, Mn and Li is adjusted according to the molar ratio of Ni, Co and Mn in the formula LiNi _x Co _y Mn _1-xy O ₂ , where x> 0, y>0, and x+y<1. The pH was adjusted to 11 by adding sodium hydroxide, and the precipitates of Ni, Co and Mn (purity: 99.3%) and the lithium-containing residual liquid were obtained after precipitation. The alkali concentration was 2.5 mol/L, the stirring speed was 150 rpm, and the stirring adjustment time was 4 h. After suction filtration, solid-liquid separation is carried out to obtain a lithium-rich solution and a mixture for preparing a Co, Ni, and Mn precursor. The obtained Co, Ni, Mn precursor mixture was subjected to a solid phase reaction at 800 ° C for 15 h to prepare a positive electrode active material. The lithium-rich solution is added with saturated sodium carbonate to obtain a white precipitate. After suction filtration, washing and drying, a high-purity lithium carbonate solid is obtained. The precipitation temperature of lithium carbonate is 90 ° C, the stirring speed of precipitation is 150 rpm, the stirring adjustment time is 5 h, the molar ratio of carbonate ions added to the lithium carbonate precipitation to the lithium ion in the solution is 2:1, and the temperature of the washing water is 90 ° C. The purity of the obtained lithium carbonate was 99.92%.

Table 1 Composition of the metal elements of the cathode material of the used lithium ion battery

metal	Al	Fe	Li	Ni	Co	Mn
content(%)	4.50	6.21	5.16	12.31	10.71	7.70

Example 2

The lithium ion battery positive electrode waste was leached with a mixed acid of trichloroacetic acid and sulfuric acid containing a sodium sulfite reducing agent (acid concentration of 3 mol/L, and a mass percentage of the reducing agent of 4%). The leaching S/L was 50 g/L, the leaching temperature was 40 ° C, the leaching time was 50 min, and the stirring speed was 150 rpm. A leachate containing Li, Ni, Co, and Mn and a leach residue were obtained. The leaching rates of the metals Li, Ni, Co and Mn were 94.60%, 92.80% and 93.20% and 93.80%, respectively, while the leaching rates of metal Al and Fe were only 2.12% and 3.46%. The leachate is subjected to high temperature concentration/rectification treatment to recover the leaching agent to obtain a residual liquid containing Co, Ni, Mn and Li. The molar ratio of nickel, cobalt and manganese in the solution containing Co, Ni, Mn and Li is adjusted according to the molar ratio of Ni, Co and Mn in the formula LiNi _x Co _y Mn _1-xy O ₂ , where x> 0, y>0, and x+y<1. The pH was adjusted to 10.4 by adding sodium hydroxide, and the precursors of Ni, Co and Mn (purity of 99.3%) and the lithium-containing residual liquid were obtained after precipitation. The alkali concentration was 2.5 mol/L, the stirring speed was 150 rpm, and the stirring adjustment time was 4 h. After filtration, a lithium-rich solution and a mixture for preparing a Co, Ni, Mn precursor were obtained. The obtained Co, Ni, Mn precursor mixture was subjected to a solid phase reaction at 800 ° C for 15 h to prepare a positive electrode active material. The lithium-rich solution is added with saturated sodium carbonate to obtain a white precipitate. After suction filtration, washing and drying, a high-purity lithium carbonate solid is obtained. The precipitation temperature of lithium carbonate is 85 ° C, the stirring speed of precipitation is 150 rpm, the stirring adjustment time is 5 h, the molar ratio of carbonate ions added to the lithium carbonate precipitation to the lithium ion in the solution is 2:1, and the temperature of the washing water is 90 ° C. The purity of the obtained lithium carbonate was 99.95%.

Table 2 Composition of metal elements of cathode material of waste lithium ion battery

metal	Al	Fe	Li	Ni	Co	Mn
Content (wt.%)	4.35	7.458.71	3.46	8.71	10.71	7.01

The Applicant declares that the present invention illustrates the process of the present invention by the above-described embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. It will be apparent to those skilled in the art that any modifications of the present invention, equivalent substitutions of the materials selected for the present invention, and the addition of the auxiliary ingredients, the selection of the specific means, etc., are all within the scope of the present invention.

Claims (10)

1. A method for recovering a positive electrode material precursor and lithium carbonate from a lithium ion battery positive electrode waste, characterized in that the waste material is obtained by mechanically breaking and sorting the powder or waste battery obtained by removing the positive electrode sheet in the production waste. Impurity positive powder, including the following steps:

   (1) leaching the lithium ion battery positive waste material with a volatile leaching agent containing a reducing agent, and separating the leaching liquid and the leaching slag;

   (2) The leaching solution obtained in the step (1) is subjected to concentrated rectification, and the leaching agent is regenerated to obtain a volatile leaching agent and a residual liquid containing Co, Ni, Mn and Li;

   (3) The residual liquid obtained in the step (2) is subjected to co-precipitation of Co, Ni, and Mn components after being controlled by components;

   (4) Step (3) After the coprecipitation is completed, solid-liquid separation is performed to obtain a lithium-rich solution and a mixture for preparing a Co, Ni, Mn precursor;

   (5) The Co, Ni, Mn mixture obtained in the step (4) is prepared by a high-temperature solid phase reaction to prepare a positive electrode material active material; the obtained lithium-rich solution is added to a saturated sodium carbonate solution to obtain a white precipitate, which is obtained after suction filtration, washing and drying. High purity lithium carbonate solid.
2. The method according to claim 1, wherein the leaching agent of step (1) is one or more of a volatile organic and/or inorganic acid mixed with one or more reducing agents. Solution

   The acid concentration is 0.1-15 mol/L, the mass percentage of the reducing agent is 0.1-20%, the leaching S/L ratio is 5-500 g/L, the leaching temperature is 5-100 ° C, and the leaching time is 5-480 min. The stirring speed is 0 to 2000 rpm.
3. The method according to claim 2, wherein the acid concentration is preferably 2 to 4 mol/L;

   The volatile acid is preferably one or a mixture of sulfuric acid, hydrochloric acid, nitric acid, trichloroacetic acid, trifluoroacetic acid, citric acid, formic acid, acetic acid;

   Preferably, the reducing agent has a mass percentage of 2 to 8%;

   Preferably, the reducing agent is one or a combination of sodium sulfite, sulfurous acid, sodium thiosulfate or hydrogen peroxide;

   Preferably, the leaching S/L is 80-150 g/L;

   Preferably, the leaching temperature is 20 to 80 ° C;

   Preferably, the stirring speed is 100 to 500 rpm.
4. The method according to claim 1, wherein the residual liquid obtained in the step (3) is subjected to co-precipitation of Co, Ni, and Mn components after being controlled by components, and is obtained by solid-liquid separation to obtain a lithium-rich solution and used for preparation. Mixing of Co, Ni, Mn precursors.
5. The method according to claim 4, wherein the composition is adjusted to adjust the molar ratio of nickel, cobalt and manganese in the solution containing nickel and cobalt to conform to the molecular formula LiNi _x Co _y Mn _1-xy O The molar ratio of Ni, Co and Mn in ₂ , where x>0, y>0, and x+y<1.
6. The method according to claim 5, wherein the adjusting the molar ratio of nickel, cobalt and manganese in the solution containing nickel and cobalt is specifically: adding a water-soluble nickel salt to the solution containing nickel, cobalt and manganese, One or a combination of at least two of a cobalt salt or a manganese salt.
7. The method according to claim 4, wherein the pH of the solution during the coprecipitation is 7 to 12, the solution for adjusting the pH is an alkaline solution, the concentration of the alkali solution is 0.1 to 10 mol/L, and the stirring speed is 0 to 2000rpm, stirring adjustment time is 0.5 ~ 72h, the pH adjustment temperature is 5 ~ 95 ° C;

   Preferably, the alkaline solution is a mixture of one or both of sodium hydroxide and aqueous ammonia.
8. The method according to claim 7, wherein the pH of the coprecipitation solution is preferably 10 to 11; the alkali concentration is preferably 2 to 4 mol/L; and the stirring speed is preferably 100 to 500 rpm; The stirring adjustment time is preferably 2 to 4 hours; and the temperature for adjusting the pH is preferably 20 to 50 °C.
9. The method according to claim 1, wherein after the coprecipitation in step (4), solid-liquid separation is performed to obtain a lithium-rich solution and a mixture for preparing a Co, Ni, Mn precursor;

   Preferably, the solid-liquid separation is achieved by suction filtration or filtration.
10. The method according to claim 1, wherein the Co, Ni, Mn precursor mixture obtained in the step (5) is prepared by a high temperature solid phase reaction to prepare a positive electrode active material;

    The obtained lithium-rich solution is subjected to high-temperature concentration/rectification treatment, and a saturated sodium carbonate solution is added to obtain a white precipitate. After suction filtration, washing and drying, a high-purity lithium carbonate solid is obtained;

    Wherein, the precipitation temperature of lithium carbonate is 20-100 ° C, the stirring speed of lithium carbonate precipitation is 0-2000 rpm, the adjustment time of precipitation stirring is 0.5-72 h, and the temperature of washing water is 10-100 ° C;

    Preferably, the high temperature solid phase reaction temperature is 600 to 850 ° C, and the reaction time is 3 to 20 h;

    Preferably, the lithium carbonate precipitation temperature is 60 to 100 ° C;

    Preferably, the lithium carbonate precipitation stirring speed is 100 to 500 rpm;

    Preferably, the lithium carbonate precipitation stirring adjustment time is 1 to 16 h;

    Preferably, the molar ratio of carbonate ions added to the lithium carbonate precipitation to lithium ions in the solution is 1 to 3:2;

    Preferably, the temperature of the washing water is 90-100 ° C

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