Method for recycling positive electrode material of waste ternary lithium battery

Abstract

The invention discloses a method for recycling a waste ternary lithium battery positive electrode material, and relates to the technical field of battery recycling. The invention relates to a method for recycling a waste ternary lithium battery positive electrode material. The method comprises the following steps: S1, reduction roasting; s2, extracting lithium with water; and S3, extracting and removing impurities. According to the method, the separation and extraction technological process of various metals is simplified, reagents consumed for separation and extraction of metal elements are reduced, and the recovery cost is reduced.

Description

[0001] This application is a divisional application of the invention patent with application number 202310859702.4, invention title "A method for recycling lithium carbonate from waste ternary lithium battery cathode material", and application date July 13, 2023. Technical Field

[0002] This invention belongs to the field of battery technology, specifically a method for recycling the cathode material of waste ternary lithium batteries. Background Technology

[0003] Lithium-ion batteries, as a green and environmentally friendly new energy source, have advantages such as high reliability, high safety, small size, and light weight, and are currently widely used in digital products, electric vehicles, and military products. With the continued use of lithium-ion batteries, the generation of used lithium-ion batteries is inevitable. Used lithium-ion batteries contain many valuable metal elements, thus possessing a certain recycling value.

[0004] A related technology discloses a method for recycling waste electrolyte from lithium-ion batteries, comprising the following steps: S1, preparing lithium-fluorine-containing slag; S2, mixing the lithium-fluorine-containing slag with water to form a slurry, adding a leaching agent to dissolve the lithium in the slag in the water, filtering to obtain a crude lithium solution; S3, adjusting the pH value with an alkaline reagent to remove impurities from the crude lithium solution to obtain a refined lithium solution; S4, adding carbonate to the refined lithium solution for precipitation to obtain crude lithium carbonate. The above recycling method has low recycling efficiency. Summary of the Invention

[0005] The purpose of this invention is to provide a method for recycling waste ternary lithium battery cathode materials, so as to solve at least one aspect of the problems and defects mentioned in the background art.

[0006] Specifically, the first aspect of this invention discloses a method for recycling waste ternary lithium battery cathode materials, comprising the following steps: S1. Reduction roasting: The waste ternary lithium battery cathode material and reducing agent are mixed and roasted to obtain the roasting product; S2, Lithium extraction by water leaching: The roasted product is mixed with water and leached, and the solid and liquid phases are separated; the liquid phase is collected to obtain the first liquid phase; S3. Extraction and impurity removal: The first liquid phase, metal extractant, and pH adjuster are mixed and extracted; after extraction, a lithium-containing aqueous phase is obtained by separation. The metal extractant comprises the following raw materials: acrylate polymer and P2O4; The preparation method of the acrylate polymer includes the following steps: S01, mixing 100 parts of isobutyl acrylate, 1 to 2 parts of trimethylolpropane trimethacrylate, 3 to 4 parts of 3-(4-methoxyphenyl)-2-propyl acrylate, 10 to 20 parts of tetraallyl silicate and 50 to 70 parts of n-butanol to obtain a first mixture; S02, then mixing the first mixture with 0.1 to 5 parts of benzoyl peroxide and reacting them.

[0007] According to one technical solution of the method of the present invention, at least the following beneficial effects are achieved: This invention first reduces some of the metal elements in the ternary material to metal through high-temperature reduction roasting; at the same time, it decomposes some of the organic impurities in the cathode material of waste ternary lithium batteries into small molecules for removal. Lithium was extracted by leaching the roasted product with water; then, a metal extractant was used for extraction to further purify the lithium-containing aqueous phase; finally, lithium was precipitated with carbonate to form high-purity lithium carbonate; thus achieving lithium recycling.

[0008] The method of this invention simplifies the process of separating and extracting various metals, reduces the reagents required for separating and extracting metal elements, lowers the recovery cost, and produces high-purity lithium carbonate.

[0009] The metal extractant of the present invention is made of acrylate polymer and P204; the acrylate polymer contains lipophilic groups such as phenyl and silicon groups, which can effectively adsorb the P204 liquid phase extractant, thereby improving the stability of the liquid phase extractant and further improving the extraction efficiency.

[0010] According to some embodiments of the present invention, the reducing agent in step S1 is biochar.

[0011] According to some embodiments of the present invention, the mass ratio of the biochar to the waste ternary lithium battery cathode material is 1:10 to 20.

[0012] According to some embodiments of the present invention, the calcination temperature in step S1 is 600°C to 900°C.

[0013] According to some embodiments of the present invention, the calcination atmosphere in step S1 is a reducing atmosphere.

[0014] According to some embodiments of the present invention, the reducing atmosphere includes hydrogen.

[0015] According to some embodiments of the present invention, the volume fraction of hydrogen in the reducing atmosphere is 10% to 12%.

[0016] According to some embodiments of the present invention, the roasting time is 3h to 6h.

[0017] According to some embodiments of the present invention, the mass-to-volume ratio of the roasted product and the water in step S2 is 1g:20mL to 30mL.

[0018] According to some embodiments of the present invention, the water immersion temperature in step S2 is 70°C to 90°C.

[0019] According to some embodiments of the present invention, the immersion time in water in step S2 is 2h to 3h.

[0020] According to some embodiments of the present invention, the mass-to-volume ratio of the metal extractant and the first liquid phase in step S3 is 1g:10mL to 20mL.

[0021] According to some embodiments of the present invention, a pH adjuster is added in step S3 to control the pH to 3-4.

[0022] According to some embodiments of the present invention, the method for preparing the metal extractant includes the following steps: The acrylate polymer and P204 were mixed and treated for 12-13 hours; solid-liquid separation was performed, and the solid phase was collected.

[0023] According to some embodiments of the present invention, the mass ratio of the acrylate polymer to P204 is 1:2 to 10.

[0024] According to some embodiments of the present invention, the method for preparing the acrylate polymer includes the following steps: S01. Isobutyl acrylate, trimethylolpropane trimethacrylate, 3-(4-methoxyphenyl)-2-acrylate, tetraallyl silicate and n-butanol are mixed to prepare the first mixture; S02, then mix the first mixture with benzoyl peroxide and react.

[0025] According to some embodiments of the present invention, the mixing temperature in step S01 is 100°C to 110°C.

[0026] According to some embodiments of the present invention, the mixing time in step S01 is 1h to 2h.

[0027] According to some embodiments of the present invention, the temperature of the reaction in step S02 is 110°C to 125°C.

[0028] According to some embodiments of the present invention, the reaction time in step S02 is 2h to 3h.

[0029] According to some embodiments of the present invention, after the reaction in step S02, the pH value is adjusted to neutral to obtain a neutral emulsion.

[0030] According to some embodiments of the present invention, the mixing temperature in step S4 is 70°C to 80°C.

[0031] According to some embodiments of the present invention, the pH of the mixture in step S4 is 8 to 11.

[0032] According to some embodiments of the present invention, the carbonate in step S4 includes sodium carbonate. Detailed Implementation

[0033] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0034] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0035] Unless otherwise specified in the examples, the procedures should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products. Example

[0036] This embodiment describes a method for recycling cathode materials from waste ternary lithium batteries, comprising the following steps: S1. The waste ternary lithium-ion battery cathode material and biochar are mixed (the mass ratio of waste ternary lithium-ion battery cathode material and biochar is 15:1) and then roasted to obtain the roasted product. The calcination temperature was 800℃, the calcination time was 6h, and the calcination atmosphere was a reducing atmosphere (argon-hydrogen, with a hydrogen volume fraction of 11%). S2. Mix the roasted product with water (the mass-to-volume ratio of the roasted product to water is 1g:28mL) and leach (leaching temperature is 90℃, time is 3h) to obtain the first liquid phase. S3, Impurity Removal: The first liquid phase, metal extractant (mass-volume ratio of metal extractant to first liquid phase is 1 g: 15 mL) and pH adjuster (30% hydrochloric acid by mass fraction) were mixed and extracted (extraction pH is 3.5); after extraction, a lithium-containing aqueous phase was obtained by separation. S4, Lithium precipitate: Lithium carbonate was prepared by mixing a lithium-containing aqueous phase with sodium carbonate (pH 10.5, temperature 75℃, time 3h), filtering after complete precipitation, washing and drying the precipitate. The metal extractant comprises the following raw materials in parts by weight: One part of acrylate polymer and eight parts of P204; The preparation method of the metal extractant in this embodiment consists of the following steps: After mixing the acrylate polymer and P204, the mixture was treated for 12 hours; solid-liquid separation was performed, and the solid phase was collected.

[0037] The acrylate polymer comprises the following raw materials in parts by weight: 100 parts isobutyl acrylate, 1.5 parts trimethylolpropane trimethacrylate, 3 parts 3-(4-methoxyphenyl)-2-propenyl acrylate, 12 parts tetraallyl silicate, 70 parts n-butanol and 3 parts benzoyl peroxide.

[0038] The preparation method of the acrylate polymer in this embodiment consists of the following steps: S1. Isobutyl acrylate, trimethylolpropane trimethacrylate, 3-(4-methoxyphenyl)-2-propenyl acrylate, tetraallyl silicate and n-butanol were mixed and kept at 110°C for 1.5 h to obtain the first mixture.

[0039] S2. Mix half of the amount of benzoyl peroxide in the formula with the first mixture and keep it at 115°C for 1.5 hours to obtain the second mixture.

[0040] S3. Mix half of the amount of benzoyl peroxide and the second mixture and keep it at 125°C for 1.5 hours. Then cool it to room temperature (25°C) and add ammonia (28% by mass) to adjust the pH to neutral. Example

[0041] This embodiment describes a method for recycling cathode materials from waste ternary lithium batteries, comprising the following steps: S1. The waste ternary lithium-ion battery cathode material and biochar are mixed (the mass ratio of waste ternary lithium-ion battery cathode material and biochar is 10:1) and then roasted to obtain the roasted product. The calcination temperature was 700℃, the calcination time was 6 hours, and the calcination atmosphere was a reducing atmosphere (argon-hydrogen, with a hydrogen volume fraction of 10%). S2. Mix the roasted product with water (the mass-volume ratio of roasted product to water is 1g:30mL) and soak in water (leaching temperature is 70℃, time is 3h) to obtain the first liquid phase; S3, Impurity Removal: The first liquid phase, metal extractant (mass-volume ratio of metal extractant to first liquid phase is 1 g: 20 mL) and pH adjuster (30% hydrochloric acid by mass fraction) were mixed and extracted (extraction pH is 3.5); after extraction, a lithium-containing aqueous phase was obtained by separation. S4, Lithium precipitate: Lithium carbonate was prepared by mixing a lithium-containing aqueous phase with sodium carbonate (pH 10.5, temperature 80℃, time 3h), filtering after complete precipitation, washing and drying the precipitate. The metal extractant comprises the following raw materials in parts by weight: One part of acrylate polymer and ten parts of P204; The preparation method of the metal extractant in this embodiment is the same as that in Example 1.

[0042] The acrylate polymer comprises the following raw materials in parts by weight: 100 parts isobutyl acrylate, 1 part trimethylolpropane trimethacrylate, 4 parts 3-(4-methoxyphenyl)-2-propenyl acrylate, 20 parts tetraallyl silicate, 70 parts n-butanol and 3 parts benzoyl peroxide.

[0043] The preparation method of the acrylate polymer in this embodiment is the same as that in Example 1. Example

[0044] This embodiment describes a method for recycling cathode materials from waste ternary lithium batteries, comprising the following steps: S1. The waste ternary lithium-ion battery cathode material and biochar are mixed (the mass ratio of waste ternary lithium-ion battery cathode material and biochar is 20:1) and then roasted to obtain the roasted product. The calcination temperature was 700℃, the calcination time was 6h, and the calcination atmosphere was a reducing atmosphere (argon-hydrogen, with a hydrogen volume fraction of 12%). S2. Mix the roasted product with water (the mass-volume ratio of roasted product to water is 1g:30mL) and soak in water (leaching temperature is 80℃, time is 3h) to obtain the first liquid phase. S3, Impurity Removal: The first liquid phase, metal extractant (mass-volume ratio of metal extractant to first liquid phase is 1 g: 10 mL) and pH adjuster (30% hydrochloric acid by mass fraction) were mixed and extracted (extraction pH is 3.5); after extraction, a lithium-containing aqueous phase was obtained by separation. S4, Lithium precipitate: Lithium carbonate was prepared by mixing a lithium-containing aqueous phase with sodium carbonate (pH 10.5, temperature 80℃, time 3h), filtering after complete precipitation, washing and drying the precipitate. The metal extractant comprises the following raw materials in parts by weight: One part of acrylate polymer and two parts of P204; The preparation method of the metal extractant in this embodiment is the same as that in Example 1.

[0045] The acrylate polymer comprises the following raw materials in parts by weight: 100 parts isobutyl acrylate, 2 parts trimethylolpropane trimethacrylate, 4 parts 3-(4-methoxyphenyl)-2-propenyl acrylate, 10 parts tetraallyl silicate, 70 parts n-butanol and 3 parts benzoyl peroxide.

[0046] The preparation method of the acrylate polymer in this embodiment is the same as that in Example 1. Example

[0047] This embodiment describes a method for recycling cathode materials from waste ternary lithium batteries, comprising the following steps: S1. The waste ternary lithium-ion battery cathode material and biochar are mixed (the mass ratio of waste ternary lithium-ion battery cathode material and biochar is 15:1) and then roasted to obtain the roasted product. The calcination temperature was 800℃, the calcination time was 4 hours, and the calcination atmosphere was a reducing atmosphere (argon-hydrogen, with a hydrogen volume fraction of 10%). S2. Mix the roasted product with water (the mass-volume ratio of roasted product to water is 1g:25mL) and soak in water (leaching temperature is 90℃, time is 3h) to obtain the first liquid phase. S3, Impurity Removal: The first liquid phase, metal extractant (mass-volume ratio of metal extractant to first liquid phase is 1 g: 18 mL) and pH adjuster (30% hydrochloric acid by mass fraction) were mixed and extracted (extraction pH is 3.5); after extraction, a lithium-containing aqueous phase was obtained by separation. S4, Lithium precipitate: Lithium carbonate was prepared by mixing a lithium-containing aqueous phase with sodium carbonate (pH 10.5, temperature 80℃, time 3h), filtering after complete precipitation, washing and drying the precipitate. The metal extractant comprises the following raw materials in parts by weight: One part of acrylate polymer and eight parts of P204; The preparation method of the metal extractant in this embodiment is the same as that in Example 1.

[0048] The acrylate polymer comprises the following raw materials in parts by weight: 100 parts isobutyl acrylate, 1.2 parts trimethylolpropane trimethacrylate, 3.8 parts 3-(4-methoxyphenyl)-2-propenyl acrylate, 18 parts tetraallyl silicate, 70 parts n-butanol and 3 parts benzoyl peroxide.

[0049] The preparation method of the acrylate polymer in this embodiment is the same as that in Example 1. Example

[0050] This embodiment describes a method for recycling cathode materials from waste ternary lithium batteries, comprising the following steps: S1. The waste ternary lithium-ion battery cathode material and biochar are mixed (the mass ratio of waste ternary lithium-ion battery cathode material and biochar is 12:1) and then roasted to obtain the roasted product. The calcination temperature was 700℃, the calcination time was 6 hours, and the calcination atmosphere was a reducing atmosphere (argon-hydrogen, with a hydrogen volume fraction of 10%). S2. Mix the roasted product with water (the mass-volume ratio of roasted product to water is 1g:25mL) and soak in water (leaching temperature is 90℃, time is 3h) to obtain the first liquid phase. S3, Impurity Removal: The first liquid phase, metal extractant (mass-volume ratio of metal extractant to first liquid phase is 1 g: 18 mL) and pH adjuster (30% hydrochloric acid by mass fraction) were mixed and extracted (extraction pH is 3.5); after extraction, a lithium-containing aqueous phase was obtained by separation. S4, Lithium precipitate: Lithium carbonate was prepared by mixing a lithium-containing aqueous phase with sodium carbonate (pH 10.5, temperature 80℃, time 3h), filtering after complete precipitation, washing and drying the precipitate. The metal extractant comprises the following raw materials in parts by weight: One part of acrylate polymer and three parts of P204; The preparation method of the metal extractant in this embodiment is the same as that in Example 1.

[0051] The acrylate polymer comprises the following raw materials in parts by weight: 100 parts isobutyl acrylate, 1.6 parts trimethylolpropane trimethacrylate, 3 parts 3-(4-methoxyphenyl)-2-propenyl acrylate, 17 parts tetraallyl silicate, 70 parts n-butanol and 3 parts benzoyl peroxide.

[0052] The preparation method of the acrylate polymer in this embodiment is the same as that in Example 1.

[0053] Comparative Example 1 This comparative example illustrates a method for recycling cathode materials from waste ternary lithium batteries, comprising the following steps: S1. The waste ternary lithium-ion battery cathode material and biochar are mixed (the mass ratio of waste ternary lithium-ion battery cathode material and biochar is 12:1) and then roasted to obtain the roasted product. The calcination temperature was 700℃, the calcination time was 6 hours, and the calcination atmosphere was a reducing atmosphere (argon-hydrogen, with a hydrogen volume fraction of 10%). S2. Mix the roasted product with water (the mass-volume ratio of roasted product to water is 1g:25mL) and soak in water (leaching temperature is 90℃, time is 3h) to obtain the first liquid phase. S3, Impurity Removal: The first liquid phase, metal extractant (mass-volume ratio of metal extractant to first liquid phase is 1 g: 18 mL) and pH adjuster (30% hydrochloric acid by mass fraction) were mixed and extracted (extraction pH is 3.5); after extraction, a lithium-containing aqueous phase was obtained by separation. S4, Lithium precipitate: Lithium carbonate was prepared by mixing a lithium-containing aqueous phase with sodium carbonate (pH 10.5, temperature 80℃, time 3h), filtering after complete precipitation, washing and drying the precipitate. The metal extractant comprises the following raw materials in parts by weight: One part of acrylate polymer (same as in Example 5) and one part of P204.

[0054] Comparative Example 2 This comparative example illustrates a method for recycling cathode materials from waste ternary lithium batteries, comprising the following steps: S1. The waste ternary lithium-ion battery cathode material and biochar are mixed (the mass ratio of waste ternary lithium-ion battery cathode material and biochar is 12:1) and then roasted to obtain the roasted product. The calcination temperature was 700℃, the calcination time was 6 hours, and the calcination atmosphere was a reducing atmosphere (argon-hydrogen, with a hydrogen volume fraction of 10%). S2. Mix the roasted product with water (the mass-volume ratio of roasted product to water is 1g:25mL) and soak in water (leaching temperature is 90℃, time is 3h) to obtain the first liquid phase. S3, Impurity Removal: The first liquid phase, metal extractant (mass-volume ratio of metal extractant to first liquid phase is 1 g: 18 mL) and pH adjuster (30% hydrochloric acid by mass fraction) were mixed and extracted (extraction pH is 3.5); after extraction, a lithium-containing aqueous phase was obtained by separation. S4, Lithium precipitate: Lithium carbonate was prepared by mixing a lithium-containing aqueous phase with sodium carbonate (pH 10.5, temperature 80℃, time 3h), filtering after complete precipitation, washing and drying the precipitate. The metal extractant comprises the following raw materials in parts by weight: One part of acrylate polymer and five parts of P204; The preparation method of the metal extractant in this comparative example is the same as that in Example 1.

[0055] The acrylate polymer comprises the following raw materials in parts by weight: 100 parts isobutyl acrylate, 3 parts propyl 3-(4-methoxyphenyl)-2-acrylate, 17 parts tetraallyl silicate, 70 parts n-butanol, and 3 parts benzoyl peroxide.

[0056] The preparation method of the acrylate polymer in this comparative example consists of the following steps: S1. Isobutyl acrylate, propyl 3-(4-methoxyphenyl)-2-acrylate, tetraallyl silicate and n-butanol were mixed and kept at 110°C for 1.5 h to obtain the first mixture.

[0057] S2. Mix half of the amount of benzoyl peroxide in the formula with the first mixture and keep it at 115°C for 1.5 hours to obtain the second mixture.

[0058] S3. Mix half of the amount of benzoyl peroxide and the second mixture and keep it at 125°C for 1.5 hours. Then cool it to room temperature (25°C) and add ammonia (28% by mass) to adjust the pH to neutral.

[0059] Comparative Example 3 This comparative example illustrates a method for recycling cathode materials from waste ternary lithium batteries, comprising the following steps: S1. The waste ternary lithium-ion battery cathode material and biochar are mixed (the mass ratio of waste ternary lithium-ion battery cathode material and biochar is 12:1) and then roasted to obtain the roasted product. The calcination temperature was 700℃, the calcination time was 6 hours, and the calcination atmosphere was a reducing atmosphere (argon-hydrogen, with a hydrogen volume fraction of 10%). S2. Mix the roasted product with water (the mass-volume ratio of roasted product to water is 1g:25mL) and soak in water (leaching temperature is 90℃, time is 3h) to obtain the first liquid phase. S3, Impurity Removal: The first liquid phase, metal extractant (mass-volume ratio of metal extractant to first liquid phase is 1 g: 18 mL) and pH adjuster (30% hydrochloric acid by mass fraction) were mixed and extracted (extraction pH is 3.5); after extraction, a lithium-containing aqueous phase was obtained by separation. S4, Lithium precipitate: Lithium carbonate was prepared by mixing a lithium-containing aqueous phase with sodium carbonate (pH 10.5, temperature 80℃, time 3h), filtering after complete precipitation, washing and drying the precipitate. The metal extractant comprises the following raw materials in parts by weight: One part of acrylate polymer and five parts of P204; The preparation method of the metal extractant in this comparative example is the same as that in Example 1.

[0060] The acrylate polymer comprises the following raw materials in parts by weight: 100 parts isobutyl acrylate, 1.6 parts trimethylolpropane trimethacrylate, 17 parts tetraallyl silicate, 70 parts n-butanol and 3 parts benzoyl peroxide.

[0061] The preparation method of the acrylate polymer in this comparative example consists of the following steps: S1. Isobutyl acrylate, trimethylolpropane trimethacrylate, tetraallyl silicate and n-butanol are mixed and kept at 110°C for 1.5 h to obtain the first mixture.

[0062] S2. Mix half of the amount of benzoyl peroxide in the formula with the first mixture and keep it at 115°C for 1.5 hours to obtain the second mixture.

[0063] S3. Mix half of the amount of benzoyl peroxide and the second mixture and keep it at 125°C for 1.5 hours. Then cool it to room temperature (25°C) and add ammonia (28% by mass) to adjust the pH to neutral.

[0064] Comparative Example 4 This comparative example illustrates a method for recycling cathode materials from waste ternary lithium batteries, comprising the following steps: S1. The waste ternary lithium-ion battery cathode material and biochar are mixed (the mass ratio of waste ternary lithium-ion battery cathode material and biochar is 12:1) and then roasted to obtain the roasted product. The calcination temperature was 700℃, the calcination time was 6 hours, and the calcination atmosphere was a reducing atmosphere (argon-hydrogen, with a hydrogen volume fraction of 10%). S2. Mix the roasted product with water (the mass-volume ratio of roasted product to water is 1g:25mL) and soak in water (leaching temperature is 90℃, time is 3h) to obtain the first liquid phase. S3, Impurity Removal: The first liquid phase, metal extractant (mass-volume ratio of metal extractant to first liquid phase is 1 g: 18 mL) and pH adjuster (30% hydrochloric acid by mass fraction) were mixed and extracted (extraction pH is 3.5); after extraction, a lithium-containing aqueous phase was obtained by separation. S4, Lithium precipitate: Lithium carbonate was prepared by mixing a lithium-containing aqueous phase with sodium carbonate (pH 10.5, temperature 80℃, time 3h), filtering after complete precipitation, washing and drying the precipitate. The metal extractant comprises the following raw materials in parts by weight: One part of acrylate polymer and five parts of P204; The preparation method of the metal extractant in this comparative example is the same as that in Example 1.

[0065] The acrylate polymer comprises the following raw materials in parts by weight: 100 parts isobutyl acrylate, 1.6 parts trimethylolpropane trimethacrylate, 3 parts 3-(4-methoxyphenyl)-2-propenyl acrylate, 70 parts n-butanol and 3 parts benzoyl peroxide.

[0066] The preparation method of the acrylate polymer in this comparative example consists of the following steps: S1. Isobutyl acrylate, trimethylolpropane trimethacrylate, 3-(4-methoxyphenyl)-2-propenyl acrylate and n-butanol were mixed and kept at 110°C for 1.5 h to obtain the first mixture.

[0067] S2. Mix half of the amount of benzoyl peroxide in the formula with the first mixture and keep it at 115°C for 1.5 hours to obtain the second mixture.

[0068] S3. Mix half of the amount of benzoyl peroxide and the second mixture and keep it at 125°C for 1.5 hours. Then cool it to room temperature (25°C) and add ammonia (28% by mass) to adjust the pH to neutral.

[0069] Comparative Example 5 This comparative example illustrates a method for recycling cathode materials from waste ternary lithium batteries, comprising the following steps: S1. The waste ternary lithium-ion battery cathode material and biochar are mixed (the mass ratio of waste ternary lithium-ion battery cathode material and biochar is 12:1) and then roasted to obtain the roasted product. The calcination temperature was 700℃, the calcination time was 6 hours, and the calcination atmosphere was a reducing atmosphere (argon-hydrogen, with a hydrogen volume fraction of 10%). S2. Mix the roasted product with water (the mass-volume ratio of roasted product to water is 1g:25mL) and soak in water (leaching temperature is 90℃, time is 3h) to obtain the first liquid phase. S3, Impurity Removal: The first liquid phase, the metal extractant (the mass-to-volume ratio of the metal extractant (P204) to the first liquid phase was 1 g: 18 mL), and the pH adjuster (30% hydrochloric acid) were mixed and extracted (the extraction pH was 3.5); the lithium-containing aqueous phase was then separated after extraction. S4, Lithium precipitate: Lithium carbonate was prepared by mixing a lithium-containing aqueous phase with sodium carbonate (pH 10.5, temperature 80℃, time 3h), allowing precipitation to complete, filtering, washing and drying the precipitate.

[0070] Table 1 shows the test data of lithium recovery rate and lithium carbonate purity in Examples 1-5 and Comparative Examples 1-5 of this invention.

[0071] Table 1. Test data on lithium recovery rate and lithium carbonate purity in Examples 1-5 and Comparative Examples 1-5 of the present invention. In summary, this invention first reduces some metal elements in ternary materials to metals through high-temperature reduction roasting; simultaneously, it decomposes organic impurities in waste ternary lithium battery cathode materials into smaller molecules for removal; lithium is leached from the roasting product using water; further purification of the lithium-containing aqueous phase is achieved through extraction using a metal extractant; finally, lithium is precipitated using carbonates to form high-purity lithium carbonate; thus achieving lithium recycling. This invention simplifies the separation and extraction process of various metals, reduces the reagents required for metal element separation and extraction, lowers recycling costs, and produces high-purity lithium carbonate. The metal extractant of this invention is made from acrylate polymers and P204; the acrylate polymers contain lipophilic groups such as phenyl and silicon groups, which can effectively adsorb the P204 liquid phase extractant, thereby improving the stability of the liquid phase extractant and further enhancing extraction efficiency.

[0072] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for recycling cathode materials from waste ternary lithium batteries, characterized in that, Includes the following steps: S1. Reduction roasting: The waste ternary lithium battery cathode material and reducing agent are mixed and roasted to obtain the roasting product; S2, Lithium extraction by water leaching: The roasted product is mixed with water and leached, and the solid and liquid phases are separated; the liquid phase is collected to obtain the first liquid phase; S3. Extraction and impurity removal: The first liquid phase, metal extractant, and pH adjuster are mixed and extracted; after extraction, a lithium-containing aqueous phase is obtained by separation. The metal extractant comprises the following raw materials: acrylate polymer and P2O4; The preparation method of the acrylate polymer includes the following steps: S01, mixing 100 parts of isobutyl acrylate, 1 to 2 parts of trimethylolpropane trimethacrylate, 3 to 4 parts of 3-(4-methoxyphenyl)-2-propyl acrylate, 10 to 20 parts of tetraallyl silicate and 50 to 70 parts of n-butanol to obtain a first mixture; S02, then mixing the first mixture with 0.1 to 5 parts of benzoyl peroxide and reacting them.

2. The method according to claim 1, characterized in that, The mass-to-volume ratio of the metal extractant to the first liquid phase in step S3 is 1g:10mL~20mL.

3. The method according to claim 1, characterized in that, In step S3, a pH adjuster is added to control the pH to 3-4.

4. The method according to claim 1, characterized in that, The mass ratio of the acrylate polymer to P204 is 1:2 to 10.

5. The method according to claim 1, characterized in that, The preparation method of the metal extractant includes the following steps: mixing and treating acrylate polymer and P204, then separating the solid and liquid phases and collecting the solid phase.

6. The method according to claim 5, characterized in that, The acrylate polymer and P204 were mixed and treated for 12 to 13 hours.

7. The method according to claim 1, characterized in that, The mixing temperature in step S01 is 100℃~110℃, and the mixing time is 1h~2h.

8. The method according to claim 1, characterized in that, The reaction temperature in step S02 is 110℃~125℃, and the reaction time is 2h~3h.

9. The method according to claim 1, characterized in that, After the reaction described in step S02, the pH value is adjusted to neutral to obtain a neutral emulsion.

10. The method according to claim 1, characterized in that, It also includes the following steps: S4, Lithium precipitation: Lithium carbonate is prepared by mixing a lithium-containing aqueous phase with carbonate.