Extracting agent for separating and recycling metal elements in battery feed liquid, extracting method and application of extracting agent

Abstract

The invention discloses an extracting agent for separating and recycling metal elements in battery feed liquid, an extracting method and application of the extracting agent and the extracting method, and belongs to the technical field of waste lithium battery recycling. The method is simple and easy to operate, is not influenced by impurity metal ions such as calcium and magnesium, and can improve the extraction capacity of a system to nickel, cobalt and manganese and inhibit the extraction capacity to lithium, calcium and magnesium by optimizing the proportion, concentration and side chain structure of the composite extraction agent, so that the separation coefficient of the system to nickel, cobalt and manganese and lithium, calcium and magnesium is improved, and efficient separation is realized. According to the method, the technological process is short, operation is easy, the separation cost for recycling nickel, cobalt and manganese and the extraction and purification cost for impurity metal ions are reduced, the purity of the recycled nickel-cobalt-manganese product exceeds 99.85%, and the recycling rate exceeds 98.5%.

Description

Technical Field

[0001] The invention belongs to the technical field of waste lithium battery recycling, and specifically relates to an extractant for separating and recycling metal elements in battery liquid, an extraction method and application thereof. Background Art

[0002] Lithium-ion batteries have shown significant application potential in the fields of electric vehicles and electronic devices due to their superior safety performance and excellent electrochemical properties. In recent years, under the influence of multiple factors such as energy, environment, and technology, the new energy vehicle industry has shown explosive development, directly driving the rapid growth of lithium-ion power battery production and installation scale. However, due to the rapid growth in electric vehicle sales, it has also led to an increase in waste lithium-ion batteries.

[0003] In 2020, the total amount of waste lithium-ion batteries was close to 250,000 tons, and by 2035, it is expected to exceed 6.76 million tons. These waste lithium batteries include toxic and corrosive electrolytes that need to be properly handled, otherwise they will have a negative impact on the environment and human health. In addition, waste lithium-ion batteries are also regarded as important secondary mineral resources because they have much more valuable metals than natural ores (such as 5%-10% nickel, 20% cobalt and 5%-7% lithium). Therefore, recycling valuable metals such as nickel, cobalt, manganese and lithium in waste lithium-ion batteries has significant environmental and economic benefits.

[0004] The prior art (CN115141933A) first removes impurities such as calcium and magnesium by fluoride precipitation, and then extracts and recovers nickel, cobalt and manganese products in one step. However, the calcium fluoride and magnesium fluoride precipitates generated by the fluoride precipitation method are easy to become colloidal and difficult to filter and separate, which easily causes the loss of valuable metals. The prior art (CN112442596A) also recovers nickel, cobalt and manganese products respectively by multi-step extraction to achieve separation from calcium and magnesium impurities, but the use of multiple extractants makes the process complicated, the production cost is high, the operation is unstable, and the existing extraction system has a low separation coefficient for nickel, cobalt and manganese and calcium and magnesium, and the separation of calcium and magnesium is not thorough.

[0005] Therefore, there is an urgent need for a new process for recovering different metal elements in battery liquid, which can effectively reduce the loss of valuable metals while achieving excellent impurity removal effects. Summary of the invention

[0006] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0007] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0008] Therefore, the purpose of the present invention is to overcome the deficiencies in the prior art and provide an extractant for separating and recovering metal elements in battery liquid.

[0009] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0010] It includes extractant I, extractant II and diluent, wherein:

[0011] The extractant I comprises one or both of a phosphoric acid extractant and a carboxylic acid extractant, and the molar concentration is 0.25 to 1.5 mol / L;

[0012] The extractant II is 4-pyridinecarboxylate, and the molar concentration is 0.25-1.5 mol / L.

[0013] The molar concentration ratio of the extractant I to the extractant II is 1:0.75-3.

[0014] As a preferred embodiment of the extractant for separating and recovering metal elements in battery liquid according to the present invention, the phosphoric acid extractant includes one or two of di(2-ethylhexyl) phosphate, 2-ethylhexyl phosphate 2-ethylhexyl ester, di(2,4,4-trimethylpentyl)phosphinic acid and di(2-ethylhexyl)phosphonic acid.

[0015] As a preferred embodiment of the extractant for separating and recovering nickel, cobalt and manganese in battery liquid according to the present invention, the carboxylic acid extractant includes one or two of cyclohexanecarboxylic acid and secondary octylphenoxy-substituted acetic acid.

[0016] As a preferred embodiment of the extractant for separating and recovering metal elements in battery liquid according to the present invention, the 4-pyridinecarboxylate ester includes one of 4-pyridinecarboxylic acid isooctyl ester, 4-pyridinecarboxylic acid n-octyl ester, 4-pyridinecarboxylic acid decyl ester and 4-pyridinecarboxylic acid dodecyl ester.

[0017] As a preferred embodiment of the extractant for separating and recovering metal elements in battery liquid according to the present invention, the diluent includes one or two of isooctyl ether, solvent oil, kerosene, hexane, heptane and dodecane.

[0018] Another object of the present invention is to provide a method for separating and recovering metal elements in battery liquid.

[0019] In order to solve the above technical problems, the present invention provides the following technical solution: using the extractant as described in any one of claims 1 to 5, comprising:

[0020] The saponified extractant is mixed with the battery liquid and shaken for extraction to obtain a raffinate water phase and an organic phase I;

[0021] The organic phase I is mixed with a detergent and shaken for washing to obtain a washing liquid aqueous phase and an organic phase II;

[0022] The organic phase II is mixed with the stripping agent and shaken for stripping to obtain a stripping liquid aqueous phase and an organic phase III;

[0023] Among them, the aqueous phase realizes the recovery of lithium elements, and the organic phase realizes the recovery of nickel, cobalt and manganese.

[0024] As a preferred scheme of the extractant for separating and recovering metal elements in battery liquid described in the present invention, the saponification is achieved by contacting a saponifying agent with an extractant, wherein the saponifying agent includes one of ammonia water, sodium hydroxide, sodium carbonate, and ammonium carbonate, and the saponification degree of the extractant is 10 to 40%.

[0025] As a preferred embodiment of the extractant for separating and recovering metal elements in battery liquid according to the present invention, the extractant is mixed with the battery liquid and shaken for extraction, wherein the ratio of the extractant to the battery liquid is in the range of 20:1 to 1:20;

[0026] The extraction is one of primary extraction, multi-stage countercurrent extraction or multi-stage cascade extraction. When the extraction is multi-stage countercurrent extraction, the number of extraction stages is 3 to 6, and when the multi-stage extraction is multi-stage cascade extraction, the number of extraction stages is 5 to 30.

[0027] The organic phase I is mixed with a detergent and shaken for washing, wherein the detergent is sulfuric acid with a concentration of 0.02 to 1.0 mol / L, and the ratio of the organic phase I to the detergent is in the range of 3:1 to 50:1;

[0028] The washing is one of single-stage washing, multi-stage countercurrent washing or multi-stage cascade washing, wherein when the washing is multi-stage countercurrent washing, the number of extraction stages is 3 to 6, and when the multi-stage washing is multi-stage cascade washing, the number of washing stages is 5 to 30.

[0029] The organic phase II is mixed with a stripping agent and shaken for stripping, wherein the stripping agent is sulfuric acid with a concentration of 0.5 to 4.0 mol / L, and the ratio of the organic phase II to the stripping agent is in the range of 3:1 to 30:1;

[0030] The stripping is one-stage stripping or multi-stage countercurrent stripping, wherein when the stripping is multi-stage countercurrent stripping, the number of extraction stages is 4 to 6.

[0031] Another object of the present invention is to provide an extractant for separating and recovering metal elements in battery liquid and its application in separating and recovering nickel, cobalt and manganese in battery liquid.

[0032] Another object of the present invention is to provide an extractant for separating and recovering metal elements in battery liquid and its application in separating and recovering lithium in battery liquid.

[0033] Beneficial effects of the present invention:

[0034] The extractant prepared by the invention can realize synchronous extraction and recovery of nickel, cobalt and manganese in the leachate of waste lithium-ion battery positive electrode materials, and is not affected by impurity metal ions such as calcium and magnesium. At the same time, the aqueous phase solution can realize lithium recovery. The process flow is short and the operation is simple. The separation cost of recovering nickel, cobalt and manganese respectively and the extraction and purification cost of impurity metal ions are reduced. The purity of the recovered nickel, cobalt and manganese products exceeds 99.85%, and the recovery rate exceeds 98.5%. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0036] Figure 1 The present invention is a process flow chart for recovering nickel, cobalt and manganese from the leaching solution of waste lithium-ion battery positive electrode materials. DETAILED DESCRIPTION

[0037] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0038] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0039] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0040] Unless otherwise specified, the raw materials used in the present invention are all commercially available.

[0041] In particular, the 4-pyridinecarboxylic acid isooctyl ester in the present invention can be synthesized according to the following method:

[0042] 1.0 mol of isonicotinic acid and 2 mol of isooctyl alcohol were added to a four-necked flask, nitrogen was filled for protection, and 1 / 3 of the total volume of the water-carrying agent octane in the water separator was added, and the mixture was heated with an oil bath. The stirrer was started, and 5.0 g of stannous oxalate solid acid catalyst was added. The mixture was heated under reflux and stirred at normal pressure. The reaction temperature was maintained at 120°C, and the mixture was reacted until no water entered the water separator. The reaction filtrate was filtered, and the filtrate was first washed with 20% sodium carbonate solution to make it weakly alkaline, and then washed with water until the washing water was neutral. The mixture was allowed to stand for stratification, and the upper organic layer was distilled under reduced pressure until there was no fraction in the distiller. Excess polyols and water were removed to obtain 4-pyridinecarboxylic acid isooctyl ester.

[0043] Other 4-pyridinecarboxylates used in the present invention can refer to this method, and those skilled in the art have the ability to synthesize the target substance by replacing the reactants.

[0044] The corresponding abbreviations of the raw materials used in the present invention are shown in Table 1.

[0045] Table 1

[0046]

[0047]

[0048] The composition of the aqueous phase feed liquid of the single-stage extraction in Examples 1 to 3 of the present invention is shown in Table 2, with a pH value of 3.0.

[0049] Table 2

[0050]

[0051] The composition of the battery liquid separated and recovered in specific embodiments 4 to 7 of the present invention is shown in Table 3.

[0052] Table 3

[0053]

[0054] Example 1

[0055] 1) Prepare the extractant according to the following formulas:

[0056] A1: 0.5 mol / L P204 + diluent isooctyl ether;

[0057] B1: 0.5 mol / L 2-isooctyl pyridinecarboxylate + diluent 2-isooctyl ether;

[0058] C1: 0.5mol / L P204 + 0.5mol / L 4-pyridinecarboxylic acid isooctyl ester + diluent isooctyl ether

[0059] 2) Extraction agent saponification:

[0060] The three extractants were saponified using 5 mol / L ammonia water. The saponification degree of extractant A was 15%, the saponification degree of organic phase No. 2 was 0, and the saponification degree of organic phase No. 3 (calculated as P204) was 15%.

[0061] 3) Extraction

[0062] Step 2) The saponified extractant organic phase is contacted with the aqueous phase feed liquid for single-stage extraction, the O / A ratio is 1 / 1, and the contact time is 20 minutes.

[0063] The extraction results are shown in Table 4.

[0064] Table 4

[0065]

[0066]

[0067] As shown in Table 4, when P204 is used for extraction alone, the system preferentially extracts calcium, and the extraction rate of calcium is as high as 90.42%, and the separation coefficient between nickel, cobalt and manganese and calcium, magnesium and lithium is only 0.004; when 4-pyridinecarboxylic acid isooctyl ester is used for extraction alone, the extraction rate of each metal ion is less than 1%, and the separation coefficient between nickel, cobalt and manganese and calcium, magnesium and lithium is 0.63. When P204 and 4-pyridinecarboxylic acid isooctyl ester are used for extraction, the system preferentially extracts nickel, cobalt and manganese, and the extraction rate of nickel, cobalt and manganese exceeds 70%. At this time, the extraction rate of calcium is only 10.13%, and the separation coefficient between nickel, cobalt and manganese and calcium, magnesium and lithium reaches 21.32, indicating that the synergistic extractant composed of P204 and 4-pyridinecarboxylic acid isooctyl ester can extract and recover nickel, cobalt and manganese from the battery leachate, and realize the efficient separation of nickel, cobalt and manganese from the impurities of calcium, magnesium and lithium.

[0068] Example 2

[0069] 1) Prepare the extractant according to the following formulas:

[0070] A2: 0.5mol / L P204+0.25mol / L 4-pyridinecarboxylic acid isooctyl ester+diluent isooctyl ether;

[0071] B2: 0.5mol / L P204+0.375mol / L 4-pyridinecarboxylic acid isooctyl ester+diluent isooctyl ether;

[0072] C2: 0.5mol / L P204+0.5mol / L 4-pyridinecarboxylic acid isooctyl ester+diluent isooctyl ether;

[0073] D2: 0.5mol / L P204+1.0mol / L 4-pyridinecarboxylic acid isooctyl ester+diluent isooctyl ether;

[0074] E2: 0.5mol / L P204+1.5mol / L 4-pyridinecarboxylic acid isooctyl ester+diluent isooctyl ether;

[0075] 2) Extraction agent saponification:

[0076] The three extractants were saponified using 5 mol / L ammonia water, and the saponification degrees of the extractants (calculated as P204) were all 15%.

[0077] 3) Extraction

[0078] Step 2) The saponified extractant organic phase is contacted with the aqueous phase feed liquid for single-stage extraction, the O / A ratio is 1 / 1, and the contact time is 20 minutes.

[0079] The extraction results are shown in Table 5.

[0080] Table 5

[0081]

[0082]

[0083] It can be seen from Table 5 that keeping the concentration of P204 unchanged and increasing the concentration of 4-isooctyl pyridinecarboxylate is beneficial to the extraction of nickel, cobalt and manganese, while inhibiting the extraction of calcium. When the concentration ratio of P204 to 4-isooctyl pyridinecarboxylate is 2:1, the separation coefficient of nickel, cobalt and manganese from calcium, magnesium and lithium is only 0.54; when the concentration ratio of P204 to 4-isooctyl pyridinecarboxylate is 1:2, the separation coefficient of nickel, cobalt and manganese from calcium, magnesium and lithium reaches 34.52. The results show that the introduction of 4-isooctyl pyridinecarboxylate is beneficial to the extraction of nickel, cobalt and manganese by the P204 extractant, but is not conducive to the extraction of calcium. At the same time, the higher the concentration of 4-isooctyl pyridinecarboxylate, the more obvious the positive synergistic effect of the system on the extraction of nickel, cobalt and manganese, and the more obvious the negative synergistic effect on the extraction of calcium. Further research found that continuing to increase the proportion of 4-isooctyl pyridinecarboxylate no longer significantly improves the separation effect. Therefore, choosing a suitable concentration ratio of P204 to 4-isooctyl pyridinecarboxylate is beneficial to the efficient separation of nickel, cobalt and manganese from impurities such as calcium, magnesium and lithium in the battery leachate.

[0084] Example 3

[0085] 1) Prepare the extractant according to the following formulas:

[0086] A3: 0.5mol / L P204+0.5mol / L 4-pyridinecarboxylic acid n-octyl ester+diluent isooctyl ether;

[0087] B3: 0.5mol / L P204+0.5mol / L 4-pyridinecarboxylic acid isooctyl ester+diluent isooctyl ether;

[0088] C3: 0.5mol / L P204+0.5mol / L 4-pyridinecarboxylic acid n-decyl ester+diluent isooctyl ether;

[0089] D3: 0.5mol / L P204+0.5mol / L 4-pyridinecarboxylic acid n-dodecyl ester+diluent isooctyl ether;

[0090] 2) Extraction agent saponification:

[0091] The three extractants were saponified using 5 mol / L ammonia water, and the saponification degrees of the extractants (calculated as P204) were all 15%.

[0092] 3) Extraction

[0093] Step 2) The saponified extractant organic phase is contacted with the aqueous phase feed liquid for single-stage extraction, the O / A ratio is 1 / 1, and the contact time is 20 minutes.

[0094] The extraction results are shown in Table 6.

[0095] Table 6

[0096]

[0097]

[0098] As shown in Table 6, by changing the side chain structure of 4-pyridinecarboxylate, the extraction ability of the system for elements such as nickel, cobalt, manganese, and calcium will be changed. It can be seen that in the present invention, the longer the side chain of 4-pyridinecarboxylate, the stronger the extraction ability of the system for nickel, cobalt, and manganese, the more obvious the inhibitory effect on calcium, and the greater the separation coefficient of the system for nickel, cobalt, and manganese from lithium, calcium, and magnesium; the greater the steric hindrance of the side chain of 4-pyridinecarboxylate, the stronger the extraction ability of the system for nickel, cobalt, and manganese, the more obvious the inhibitory effect on calcium, and the greater the separation coefficient of the system for nickel, cobalt, and manganese from lithium, calcium, and magnesium. Therefore, the synergistic extraction system of 4-pyridinecarboxylic acid isooctyl ester + P204 is more conducive to achieving efficient separation of nickel, cobalt, and manganese from impurities of calcium, magnesium, and lithium in the battery leachate.

[0099] Example 4

[0100] This embodiment provides a method for separating and recovering nickel, cobalt and manganese in battery liquid, specifically:

[0101] 1) Extraction agent saponification: The composition of the extraction agent is 0.75 mol / L P204+0.75 mol / L 4-pyridinecarboxylic acid isooctyl ester+isooctyl ether diluent, which is saponified by ammonia water and has a saponification degree of 40%;

[0102] 2) Extraction and washing: The saponified extractant is mixed with the battery liquid and the detergent and shaken to perform a cascade extraction and washing process. The extraction stages are 6 extraction stages, the washing stages are 7 washing stages, and the organic phase volume: the aqueous phase liquid volume: the detergent volume is 20.8ml: 2ml: 2.355mL;

[0103] After washing, washing liquid and organic phase II were obtained. The metal ion contents at the outlet of the water phase (washing liquid) and the outlet of the organic phase II were measured. The results are shown in Table 6.

[0104] Table 6

[0105]

[0106] It can be seen that after the extraction operation, the contents of Li, Ca and Mg in the organic phase outlet are low, and the impurity removal effect is obvious; the nickel, cobalt and manganese yield at the organic phase outlet exceeds 98.5%, and the purity exceeds 99.85%, so this method has high economic benefits.

[0107] 3) Stripping: The organic phase II obtained in step 2) was mixed with 2.5 mol / L sulfuric acid in a ratio of 20:1 for three-stage countercurrent stripping, stirred at 25° C. for 5 min at a speed of 500 rpm, and then allowed to stand for 5 min to separate the organic phase III and the aqueous phase. The stripping rate of Ni, Co, and Mn in the final organic phase III was calculated to be more than 99.5%, thereby realizing the recovery of nickel, cobalt, and manganese in the battery feed solution.

[0108] Example 5

[0109] This embodiment provides a method for separating and recovering nickel, cobalt and manganese in battery liquid, specifically:

[0110] 1) Extraction agent saponification: The composition of the extraction agent is 0.75 mol / L P507 + 0.75 mol / L 4-pyridinecarboxylic acid isooctyl ester + isooctyl ether diluent, which is saponified by ammonia water and has a saponification degree of 40%;

[0111] 2) Extraction and washing: The saponified extractant is mixed with the battery liquid and the detergent and shaken to perform a cascade extraction and washing process. The extraction stages are 6 extraction stages, the washing stages are 9 washing stages, and the organic phase volume: the aqueous phase liquid volume: the detergent volume is 24.5ml: 2ml: 4.015mL;

[0112] After washing, washing liquid and organic phase II were obtained. The metal ion contents at the outlet of the aqueous phase (washing liquid) and the outlet of the loaded organic phase in this step were measured. The results are shown in Table 7.

[0113] Table 7

[0114]

[0115] It can be seen that after the extraction operation, the contents of Li, Ca and Mg in the organic phase outlet are low, and the impurity removal effect is obvious.

[0116] 3) Stripping: The washed organic phase was mixed with 2.5 mol / L sulfuric acid in a ratio of 20:1 for three-stage countercurrent stripping, stirred at 25°C for 5 min at a speed of 500 rpm, and then allowed to stand for 5 min to separate the organic phase and the aqueous phase. The stripping rate of Ni, Co, and Mn in the final organic phase exceeded 99.8%, realizing the recovery of nickel, cobalt, and manganese in the battery feed liquid. The final organic phase III outlet nickel, cobalt, and manganese yield was calculated to exceed 99.9%, and the purity exceeded 99.99%.

[0117] Example 6

[0118] This embodiment provides a method for separating and recovering nickel, cobalt and manganese in battery liquid, specifically:

[0119] 1) Extraction agent saponification: The composition of the extraction agent is 0.75 mol / L CA12 + 0.75 mol / L 4-pyridinecarboxylic acid isooctyl ester + isooctyl ether diluent, which is saponified by ammonia water and has a saponification degree of 40%;

[0120] 2) Extraction and washing: The saponified extractant is mixed with the battery liquid and the detergent and shaken to perform a cascade extraction and washing process. The extraction stages are 13 extraction stages, the washing stages are 7 washing stages, and the organic phase volume: aqueous phase liquid volume: detergent volume is 25.7ml: 2ml: 4.45mL;

[0121] After washing, washing liquid and organic phase II are obtained. The metal ion contents at the outlet of the raffinate water phase (washing liquid) and the outlet of the organic phase II in this step are measured and the results are shown in Table 8.

[0122] Table 8

[0123]

[0124] (3) Stripping: The organic phase II obtained in step 2) was mixed with 2.5 mol / L sulfuric acid at a ratio of 20:1 for three-stage countercurrent stripping, stirred at 25°C for 5 min at a speed of 500 rpm, and then allowed to stand for 5 min to separate the organic phase and the aqueous phase. Finally, the stripping rate of Ni, Co, and Mn in the organic phase exceeded 99.5%, thereby realizing the recovery of nickel, cobalt, and manganese in the battery feed solution.

[0125] Example 7

[0126] This embodiment provides a method for separating and recovering nickel, cobalt and manganese in battery liquid, specifically:

[0127] 1) Extraction agent saponification: The composition of the extraction agent is 0.75 mol / L P507 + 1.5 mol / L 4-pyridinecarboxylic acid isooctyl ester + isooctyl ether diluent, which is saponified by ammonia water and has a saponification degree of 40%;

[0128] 2) Extraction and washing: The saponified extractant is mixed with the battery liquid and the detergent and shaken to perform a cascade extraction and washing process. The extraction stages are 6 extraction stages, and the washing stages are 7 washing stages. The volume of the organic phase: the volume of the aqueous phase liquid: the volume of the detergent is 21.5 ml: 2 ml: 2.63 mL;

[0129] After washing, washing liquid and organic phase II were obtained. The contents of metal ions at the outlet of the raffinate phase (washing liquid) and the outlet of the organic phase II were measured. The results are shown in Table 9.

[0130] Table 9

[0131]

[0132] It can be seen that after extraction, the contents of Li, Ca and Mg in the organic phase outlet are low, the impurity removal effect is obvious, the nickel, cobalt and manganese yield at the organic phase outlet exceeds 99.9%, and the purity exceeds 99.99%, so this method has high economic benefits.

[0133] 3) Stripping: The organic phase II obtained in step 2) was mixed with 2.5 mol / L sulfuric acid in a ratio of 20:1 for three-stage countercurrent stripping, stirred at 25° C. for 5 min at a speed of 500 rpm, and then allowed to stand for 5 min to separate the organic phase and the aqueous phase. Finally, the stripping rate of Ni, Co, and Mn in the organic phase exceeded 99.7%, thereby realizing the recovery of nickel, cobalt, and manganese in the battery feed solution.

[0134] In summary, the extractant and extraction method provided by the present invention can realize the synchronous extraction and recovery of nickel, cobalt and manganese in the leachate of waste lithium-ion battery positive electrode materials, and are not affected by impurity metal ions such as calcium and magnesium. By optimizing the proportion, concentration and side chain structure of the composite extractant, the system's ability to extract nickel, cobalt and manganese can be improved, and the extraction ability to lithium, calcium and magnesium can be suppressed, thereby improving the system's separation coefficient for nickel, cobalt and manganese and lithium, calcium and magnesium, and achieving efficient separation.

[0135] The process of the invention is short and easy to operate, thereby reducing the separation cost of recovering nickel, cobalt and manganese and the extraction and purification cost of impure metal ions. The purity of the recovered nickel, cobalt and manganese products can reach 99.99%, and the recovery rate can reach 99.99%.

[0136] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. An extractant for separating and recovering metal elements in battery liquid, characterized in that: include, Extractant I, extractant II and diluent, wherein: The extractant I comprises one or both of a phosphoric acid extractant and a carboxylic acid extractant, and the molar concentration is 0.25 to 1.5 mol / L; The extractant II is 4-pyridinecarboxylate, and the molar concentration is 0.25-1.5 mol / L. The molar concentration ratio of the extractant I to the extractant II is 1:0.75-3.

2. The extractant for separating and recovering metal elements in battery liquid according to claim 1, characterized in that: The phosphoric acid extractant includes one or two of di(2-ethylhexyl) phosphate, 2-ethylhexyl phosphate 2-ethylhexyl ester, di(2,4,4-trimethylpentyl)phosphinic acid and di(2-ethylhexyl)phosphonic acid.

3. The extractant for separating and recovering metal elements in battery liquid according to claim 1, characterized in that: The carboxylic acid extractant comprises one or two of cycloalkane acid and secondary octylphenoxy substituted acetic acid.

4. The extractant for separating and recovering metal elements in battery liquid according to claim 1, characterized in that: The 4-pyridinecarboxylate includes one of 4-pyridinecarboxylic acid isooctyl ester, 4-pyridinecarboxylic acid n-octyl ester, 4-pyridinecarboxylic acid decyl ester and 4-pyridinecarboxylic acid dodecyl ester.

5. The extractant for separating and recovering metal elements in battery liquid according to claim 1, characterized in that: The diluent includes one or two of isooctyl ether, solvent oil, kerosene, hexane, heptane and dodecane.

6. A method for separating and recovering metal elements in battery liquid, characterized in that: The extractant according to any one of claims 1 to 5 is used, comprising: The saponified extractant is mixed with the battery liquid and shaken for extraction to obtain a raffinate water phase and an organic phase I; The organic phase I is mixed with a detergent and shaken for washing to obtain a washing liquid aqueous phase and an organic phase II; The organic phase II is mixed with the stripping agent and shaken for stripping to obtain a stripping liquid aqueous phase and an organic phase III; Among them, the aqueous phase realizes the recovery of lithium elements, and the organic phase realizes the recovery of nickel, cobalt and manganese.

7. The method for separating and recovering metal elements in battery liquid according to claim 6, characterized in that: The saponification is achieved by contacting a saponifying agent with an extracting agent, wherein the saponifying agent includes one of ammonia water, sodium hydroxide, sodium carbonate, and ammonium carbonate, and the saponification degree of the extracting agent is 10-40%.

8. The method for separating and recovering metal elements in battery liquid according to claim 6, characterized in that: The extractant and the battery liquid are mixed and shaken for extraction, wherein the ratio of the extractant to the battery liquid is in the range of 20:1 to 1:20; The extraction is one of primary extraction, multi-stage countercurrent extraction or multi-stage cascade extraction, wherein when the extraction is multi-stage countercurrent extraction, the number of extraction stages is 3 to 6, and when the multi-stage extraction is multi-stage cascade extraction, the number of extraction stages is 5 to 30; The organic phase I is mixed with a detergent and shaken for washing, wherein the detergent is sulfuric acid with a concentration of 0.02 to 1.0 mol / L, and the ratio of the organic phase I to the detergent is in the range of 3:1 to 50:1; The washing is one of single-stage washing, multi-stage countercurrent washing or multi-stage cascade washing, wherein when the washing is multi-stage countercurrent washing, the number of extraction stages is 3 to 6, and when the multi-stage washing is multi-stage cascade washing, the number of washing stages is 5 to 30. The organic phase II is mixed with a stripping agent and shaken for stripping, wherein the stripping agent is sulfuric acid with a concentration of 0.5 to 4.0 mol / L, and the ratio of the organic phase II to the stripping agent is in the range of 3:1 to 30:1; The stripping is one-stage stripping or multi-stage countercurrent stripping, wherein when the stripping is multi-stage countercurrent stripping, the number of extraction stages is 4 to 6.

9. Use of the extractant according to any one of claims 1 to 5 or the extraction method according to claim 6 in separating and recovering nickel, cobalt and manganese from battery liquid.

10. Use of the extractant according to any one of claims 1 to 5 or the extraction method according to claim 6 in separating and recovering lithium from battery liquid.

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