A method for extracting metal ions from spent lithium-ion battery cathode materials

Abstract

The present application relates to a kind of methods for extracting metal ions from waste lithium ion battery positive material, comprising the following steps: S1: after lithium battery positive material is extracted lithium by sulfuric acid, the pH of leaching solution is adjusted to 4.0-5.0;S2: organic phosphate is mixed with diluent, saponification is carried out using high concentration sodium hydroxide solution or ammonium hydroxide solution, and organic component A1 is obtained;S3: long-chain carboxylic acid is mixed with diluent, and organic component A2 is prepared;S4: after organic component A1 and organic component A2 are mixed, additive is added to prepare organic phase;S5: organic phase is mixed with leaching solution according to certain proportion, and multistage countercurrent extraction process is adopted, organic phase is separated, and raffinate is obtained;S6: raffinate is concentrated by evaporation and crystallization, and the mixture of nickel sulfate and cobalt sulfate is obtained.The method of the present application can significantly increase the extraction of manganese, iron and other impurities, thereby reducing the extraction of cobalt and nickel, so as to achieve the effect of separating and purifying cobalt and nickel, and realize the purification and recovery of cobalt and nickel.

Description

Technical Field

[0001] This invention relates to the field of waste lithium-ion battery recycling technology, and in particular to a method for extracting metal ions from the cathode material of waste lithium-ion batteries. Background Technology

[0002] With the development of electric vehicles and renewable energy, the demand for lithium-ion batteries is constantly increasing, and the disposal of waste lithium-ion batteries has become an important environmental and resource management issue. Since waste lithium-ion batteries contain abundant valuable metals, the current conventional practice is to extract lithium from the positive electrode through acid leaching, and then separate and purify cobalt and nickel from the remaining leachate.

[0003] Regarding extraction and separation techniques for valuable metals, WO2005073415A1 discloses a solvent extraction method for separating cobalt and / or manganese from impurities in a leachate. This method includes a step of solvent extraction of the leachate using an organic solution of a carboxylic acid such as Versatic 10 and a hydroxy oxime such as Lix 63, optionally along with a stabilizer. Cobalt, nickel, and manganese are extracted sequentially, i.e., cobalt is extracted first, followed by nickel, while manganese is retained in the raffinate, thereby achieving the effect of recovering cobalt and nickel from a solution with high manganese and low cobalt / nickel concentrations. However, the synthesis process of the synergistic extractant used in this method is relatively complex and costly. Furthermore, due to limitations in the separation coefficient, it is difficult to separate sulfate solutions with high nickel and low cobalt (Ni / Co>50), and the separation efficiency needs further improvement. Summary of the Invention

[0004] Therefore, it is necessary to provide a method for extracting metal ions from waste lithium-ion battery cathode materials to address the problems existing in the prior art.

[0005] A method for extracting metal ions from waste lithium-ion battery cathode materials includes the following steps: S1: After extracting lithium from waste lithium-ion battery cathode materials by sulfuric acid leaching, a leachate is obtained, and the pH of the leachate is adjusted to 4.0-5.0; S2: The organophosphate ester is uniformly mixed into the diluent to prepare a mixed extractant, and then saponified with a sodium hydroxide solution or ammonium hydroxide solution with a concentration of 12.0 mol / L to 15.0 mol / L to obtain an organic component A1 with a saponification rate of 50% to 80%. S3: Medium- and long-chain carboxylic acids are uniformly mixed into a diluent to obtain organic component A2; S4: Mix organic component A1 and organic component A2 in a 1:1 ratio, and add additives to obtain an organic phase; S5: Mix the organic phase and the leachate in a certain proportion, and mix them at a temperature of 20℃~40℃ and a speed of 100r / min~500r / min for 5min~30min to ensure full contact. Then, adopt a multi-stage countercurrent extraction process to separate the organic phase and obtain the raffinate. Wash away some of the cobalt and nickel in the organic phase with sulfuric acid solution, and then back-extract the remaining manganese and impurities in the organic phase through a back-extraction process. S6: The raffinate is concentrated and crystallized by evaporation to obtain a mixture of nickel sulfate and cobalt sulfate.

[0006] In one embodiment, in step S1, the total metal ion concentration in the leachate is 20 g / L to 150 g / L; wherein the concentration of Li+ is ≤3 g / L, and the total concentration of Co2+ and Ni2+ is 10 g / L to 75 g / L.

[0007] In one embodiment, the main components of the lithium-ion battery cathode material include, but are not limited to, one or more of ternary lithium manganese cobalt nickel oxide, lithium nickel cobalt aluminum oxide, or lithium cobalt oxide.

[0008] In one embodiment, the organophosphate is one or more of isoalkylphosphonic acid (1-methyl-heptyl), 2-ethylhexyl phosphate, 2-ethylhexyl phosphate mono-2-ethylhexyl ester, or di(2,4,4-trimethylpentyl)phosphonic acid; The volume of the organophosphate ester accounts for 5% to 30% of the total organic phase volume.

[0009] In one embodiment, the medium-long chain carboxylic acid is one or more of (2-methylethyl)heptanoic acid, (2-methylhexyl)decanoic acid, 2-ethylhexanoic acid, or 2-hexyldecanoic acid; The volume of the medium- and long-chain carboxylic acids accounts for 5% to 30% of the total organic phase volume.

[0010] In one embodiment, the diluent is one or more of D60 solvent oil, D80 solvent oil, or sulfonated kerosene.

[0011] In one embodiment, the adjuvant is one or more of tributyl phosphate or 2-octanol; The volume of the auxiliary agent accounts for 1% to 10% of the total organic phase volume.

[0012] In one embodiment, in step S5, the ratio of the organic phase to the leachate is 5:1 to 1:1.

[0013] In one embodiment, in step S5, the number of back-extraction stages is 3 to 7.

[0014] In one embodiment, in step S5, the concentration of the sulfuric acid solution is 0.0005 mol / L to 3 mol / L.

[0015] The above-mentioned method for extracting metal ions from the cathode material of waste lithium-ion batteries utilizes sulfuric acid solution to extract lithium and employs a complex extraction system composed of organic phosphoric acid, organic phosphate esters, and medium- and long-chain fatty acids to extract and separate the leachate after lithium extraction from waste lithium-ion batteries. Due to the presence of a shielding effect, the extraction of impurities such as manganese and iron can be significantly increased, thereby reducing the extraction of cobalt and nickel. This achieves the separation and purification of cobalt and nickel, realizing the purification and recovery of cobalt and nickel. Attached Figure Description

[0016] Figure 1 This is a diagram of the multi-stage countercurrent extraction of the present invention.

[0017] Wherein, A is the leachate, O is the organic phase, R is the raffinate, and E is the supported organic phase. Detailed Implementation

[0018] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0019] It should be noted that when an element is said to be "fixed to" another element, it can be directly on the other element or there may be an intervening element. When an element is said to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. Conversely, when an element is said to be "directly on" another element, there is no intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0021] A method for extracting metal ions from waste lithium-ion battery cathode materials includes the following steps: S1: After extracting lithium from waste lithium-ion battery cathode materials by sulfuric acid leaching, a leachate is obtained, and the pH of the leachate is adjusted to 4.0-5.0; S2: The organophosphate ester is uniformly mixed into the diluent to prepare a mixed extractant, and then saponified with a sodium hydroxide solution or ammonium hydroxide solution with a concentration of 12.0 mol / L to 15.0 mol / L to obtain an organic component A1 with a saponification rate of 50% to 80%. S3: Medium- and long-chain carboxylic acids are uniformly mixed into the diluent to obtain organic component A2; S4: Mix organic component A1 and organic component A2 in a 1:1 ratio, and add additives to obtain an organic phase; S5: Mix the organic phase and the leachate in a certain proportion, and mix them at a temperature of 20℃~40℃ and a speed of 100r / min~500r / min for 5min~30min to ensure full contact. Then, adopt a multi-stage countercurrent extraction process to separate the organic phase and obtain the raffinate. Wash away some of the cobalt and nickel in the organic phase with sulfuric acid solution, and then back-extract the remaining manganese and impurities in the organic phase through a back-extraction process. S6: The raffinate is concentrated and crystallized by evaporation to obtain a mixture of nickel sulfate and cobalt sulfate.

[0022] Furthermore, the main components of the lithium-ion battery cathode material include, but are not limited to, one or more of ternary lithium manganese cobalt nickel oxide, lithium nickel cobalt aluminum oxide, or lithium cobalt oxide; and, in step S1, the total metal ion concentration in the leachate is 20 g / L to 150 g / L, wherein the concentration of Li+ is ≤3 g / L, and the total concentration of Co2+ and Ni2+ is 10 g / L to 75 g / L.

[0023] Further, the organophosphate ester is one or more selected from isoalkylphosphonic acid (1-methyl-heptyl), 2-ethylhexyl phosphate, 2-ethylhexyl phosphate mono-2-ethylhexyl ester, or di(2,4,4-trimethylpentyl)phosphonic acid; the medium- and long-chain carboxylic acid is one or more selected from (2-methylethyl)heptanoic acid, (2-methylhexyl)decanoic acid, 2-ethylhexanoic acid, or 2-hexyldecanoic acid; the diluent is one or more selected from D60 solvent oil, D80 solvent oil, or sulfonated kerosene; and the auxiliary agent is one or more selected from tributyl phosphate or 2-octanol. Specifically, in this invention, the volume of the organophosphate ester accounts for 5% to 30% of the total organic phase volume; the volume of the medium- and long-chain carboxylic acid accounts for 5% to 30% of the total organic phase volume; and the volume of the auxiliary agent accounts for 1% to 10% of the total organic phase volume.

[0024] Furthermore, in step S5, the ratio of the organic phase to the leachate is 5:1 to 1:1; and the number of back-extraction stages is 3 to 7.

[0025] Furthermore, in step S5, the concentration of the sulfuric acid solution is 0.0005 mol / L to 3 mol / L.

[0026] It should be noted that the extraction system of the extractant in this invention is designed based on the shielding effect in extraction. The extraction system mainly consists of organophosphates and medium- and long-chain carboxylic acids. Due to the shielding effect, the extraction rate of impurities such as manganese and iron in the leachate is increased while the extraction rate of cobalt and nickel is reduced. This increases the separation coefficient between impurities such as manganese and iron and cobalt and nickel, thereby achieving the separation and purification of cobalt and nickel, realizing the recovery of cobalt and nickel, and obtaining battery-grade cobalt / nickel mixed solutions or their sulfate / hydrochloride salts, etc. Example

[0027] First, lithium extraction is achieved by leaching waste lithium-ion battery cathode materials with sulfuric acid to obtain a leachate. The leachate contains Li+ at a concentration of 1 g / L to 3 g / L, Mn2+ at 45 g / L to 50 g / L, Co2+ at 15 g / L to 20 g / L, and Ni2+ at 50 g / L to 60 g / L. Then, the pH of the leachate is adjusted to 4.0 to 5.0 using a 1 mol / L dilute sulfuric acid and 1 mol / L sodium hydroxide solution. Next, a 15% (v / v) sulfonated kerosene solution of (2-ethylhexyl) phosphate is prepared and saponified with a 12.5 mol / L sodium hydroxide solution to obtain organic component A1 with a saponification rate of 75%. Simultaneously, a 15% (v / v) sulfonated kerosene solution of 2-hexyldecanoic acid is prepared as organic component A2. Organic components A1 and organic... Component A2 was mixed in a 1:1 ratio, and 5% tributyl phosphate and 3% 2-octanol were added to prepare an organic phase. The organic phase was then mixed with the leachate in a 3:1 ratio and stirred at 200 rpm at 25°C to ensure thorough contact. A five-stage countercurrent extraction was performed after a single-stage extraction of 15 min. The organic phase was then separated to obtain the raffinate, which was washed with sulfuric acid to remove some cobalt and nickel. The remaining manganese and impurities were then back-extracted from the organic phase using a back-extraction process. During this process, the extraction rates were 95.8% for lithium, 97.6% for manganese, 1.25% for cobalt, and 0.99% for nickel. Finally, the raffinate was concentrated and crystallized by evaporation to obtain a mixture of nickel sulfate and cobalt sulfate. Example

[0028] First, lithium extraction was achieved by leaching waste lithium-ion battery cathode materials with sulfuric acid, yielding a leachate with the following concentrations: Li+ (0.3 g / L–1 g / L), Mn2+ (20 g / L–30 g / L), Co2+ (20 g / L–25 g / L), and Ni2+ (45 g / L–55 g / L). The pH of the leachate was then adjusted to 4.3–4.8 using a 1 mol / L dilute sulfuric acid and 1 mol / L sodium hydroxide solution. Next, a 10% (v / v) solution of 2-ethylhexyl phosphate mono-2-ethylhexyl ester (D60 solvent oil) was prepared and saponified with a 14 mol / L sodium hydroxide solution to obtain organic component A1 with a saponification rate of 50%. Simultaneously, a 10% (v / v) solution of (2-methylethyl)heptanoic acid and an 8% (v / v) solution of 2-hexyldecanoic acid (D60 solvent oil) was prepared as the organic component... Organic components A1 and A2 were mixed in a 1:1 ratio, and 3% tributyl phosphate and 2% sec-octanol were added to obtain an organic phase. The organic phase was then mixed with the leachate in a 5:1 ratio and stirred at 100 rpm at 40°C to ensure thorough contact. A seven-stage countercurrent extraction was performed after a single-stage extraction of 10 min. The organic phase was then separated to obtain the raffinate, which was washed with sulfuric acid to remove some cobalt and nickel. The remaining manganese and impurities were then back-extracted from the organic phase using a back-extraction process. During this process, the extraction rates were 97.3% for lithium, 99.1% for manganese, 2.51% for cobalt, and 1.54% for nickel. Finally, the raffinate was concentrated and crystallized by evaporation to obtain a mixture of nickel sulfate and cobalt sulfate.

[0029] The above-mentioned method for extracting metal ions from the cathode material of waste lithium-ion batteries utilizes sulfuric acid solution to extract lithium and employs a complex extraction system composed of organic phosphoric acid, organic phosphate esters, and medium- and long-chain fatty acids to extract and separate the leachate after lithium extraction from waste lithium-ion batteries. Due to the presence of a shielding effect, the extraction of impurities such as manganese and iron can be significantly increased, thereby reducing the extraction of cobalt and nickel. This achieves the separation and purification of cobalt and nickel, realizing the purification and recovery of cobalt and nickel.

[0030] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0031] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for extracting metal ions from waste lithium-ion battery cathode materials, characterized in that, Includes the following steps: S1: After extracting lithium from waste lithium-ion battery cathode materials by sulfuric acid leaching, a leachate is obtained, and the pH of the leachate is adjusted to 4.0-5.0; S2: The organophosphate ester is uniformly mixed into the diluent to prepare a mixed extractant, and then saponified with a sodium hydroxide solution or ammonium hydroxide solution with a concentration of 12.0 mol / L to 15.0 mol / L to obtain an organic component A1 with a saponification rate of 50% to 80%. S3: Medium- and long-chain carboxylic acids are uniformly mixed into the diluent to obtain organic component A2; S4: Mix organic component A1 and organic component A2 in a 1:1 ratio, and add additives to obtain an organic phase; S5: Mix the organic phase and the leachate in a certain proportion, and mix them at a temperature of 20℃~40℃ and a speed of 100r / min~500r / min for 5min~30min to ensure full contact. Then, adopt a multi-stage countercurrent extraction process to separate the organic phase and obtain the raffinate. Wash away some of the cobalt and nickel in the organic phase with sulfuric acid solution, and then back-extract the remaining manganese and impurities in the organic phase through a back-extraction process. S6: The raffinate is concentrated and crystallized by evaporation to obtain a mixture of nickel sulfate and cobalt sulfate.

2. The method for extracting metal ions from waste lithium-ion battery cathode materials according to claim 1, characterized in that, In step S1, the total metal ion concentration in the leachate is 20 g / L to 150 g / L; wherein, Li + The concentration of Co is ≤3g / L. 2+ and Ni 2+ The total concentration is 10 g / L to 75 g / L.

3. The method for extracting metal ions from waste lithium-ion battery cathode materials according to claim 1, characterized in that, The main components of the lithium-ion battery cathode material include, but are not limited to, one or more of ternary manganese cobalt nickel oxide, lithium nickel cobalt aluminum oxide, or lithium cobalt oxide.

4. The method for extracting metal ions from waste lithium-ion battery cathode materials according to claim 1, characterized in that, The organophosphate ester is one or more of 2-ethylhexyl phosphate mono-2-ethylhexyl ester or bis(2,4,4-trimethylpentyl)phosphonic acid; The volume of the organophosphate ester accounts for 5% to 30% of the total organic phase volume.

5. The method for extracting metal ions from waste lithium-ion battery cathode materials according to claim 1, characterized in that, The medium- and long-chain carboxylic acids are one or more of 2-hexyldecanoic acid or 2-ethylhexanoic acid; The volume of the medium- and long-chain carboxylic acids accounts for 5% to 30% of the total organic phase volume.

6. The method for extracting metal ions from waste lithium-ion battery cathode materials according to claim 1, characterized in that, The diluent is one or more of D60 solvent oil, D80 solvent oil, or sulfonated kerosene.

7. The method for extracting metal ions from waste lithium-ion battery cathode materials according to claim 1, characterized in that, The adjuvant is one or more of tributyl phosphate or 2-octyl alcohol; The volume of the auxiliary agent accounts for 1% to 10% of the total organic phase volume.

8. The method for extracting metal ions from waste lithium-ion battery cathode materials according to claim 1, characterized in that, In step S5, the ratio of the organic phase to the leachate is 5:1 to 1:

1.

9. The method for extracting metal ions from waste lithium-ion battery cathode materials according to claim 1, characterized in that, In step S5, the number of back-extraction stages is 3 to 7.

10. The method for extracting metal ions from waste lithium-ion battery cathode materials according to claim 1, characterized in that, In step S5, the concentration of the sulfuric acid solution is 0.0005 mol / L to 3 mol / L.

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