A method for separating Li / Co / Mn / Ni in solution and its application

Abstract

The present invention discloses a method for separating Li / Co / Mn / Ni in a solution and its application, belonging to the field of resource recovery technology. The above method comprises: extracting transition metal ions in a mixed metal solution containing Li, Co, Mn and Ni with an organic phase A to obtain a loaded organic phase A and a raffinate phase A; the composite extractant in the organic phase A is composed of a Primene extractant and Cyanex 272 mixed in a volume ratio of ≥1.5; stripping the loaded organic phase A to obtain a stripping phase A; extracting the stripping phase A with an organic phase B containing P204 to obtain a loaded organic phase B and a raffinate phase B; adjusting the pH of the raffinate phase B to ≥4, and then extracting the raffinate phase B with an organic phase C containing Cyanex 272 to obtain a loaded organic phase C and a raffinate phase C. The method provided by the present invention can comprehensively and independently recover Li, Co, Mn and Ni from an aqueous solution. The present invention also provides applications of the above method.

Description

Technical Field

[0001] The present invention relates to the technical field of resource recovery, and in particular to a method for separating Li / Co / Mn / Ni in a solution and application thereof. Background Art

[0002] In recent years, lithium-ion batteries have become the preferred power source for portable electronic devices such as mobile phones, laptops, and digital cameras due to their advantages such as high energy density, large specific capacity, long cycle life, and environmental friendliness. Their application in new energy industries such as electric vehicles is also gradually expanding.

[0003] After hundreds of charge and discharge cycles, lithium batteries (LIBs) will undergo irreversible changes in their internal structure, which will block the Li + The diffusion channels of LIBs are blocked, eventually causing them to become inactivated and scrapped. As a result, the average lifespan of LIBs is only 1 to 3 years. With the increasing demand and production of LIBs in the 3C small appliance and power battery sectors, a large number of retired lithium batteries will be generated in a spurt.

[0004] At the same time, as the new energy vehicle market expands, the growth in LIB production will inevitably drive a rapid increase in demand for related metal raw materials, and metals such as lithium, cobalt, and nickel will remain relatively high in price. Nickel and cobalt resources are unevenly distributed and not very abundant, making supply likely to outstrip demand. Traditional lithium production has been experiencing passive growth, leading to an increasingly prominent supply-demand imbalance.

[0005] It's worth noting that discarded LIBs contain many toxic and valuable metal elements. For example, NCM batteries contain heavy metals, organic chemicals, and plastics, with the proportions being 5-20wt% cobalt, 5-10wt% nickel, 5-7wt% lithium, 15wt% organic chemicals, and 7wt% plastic, respectively. In addition to lithium cobalt oxide (LCO), commonly used cathode materials include LiNiO2, LiMnO2, and ternary materials like nickel-cobalt-manganese oxide (LCOMnO), all of which have high recycling value. Failure to recycle discarded LIBs not only results in significant environmental pollution but also wastes resources.

[0006] Recycling lithium batteries not only protects the ecological environment to a certain extent, but also alleviates my country's shortage of metal resources and promotes the sustainable development of the lithium-ion new energy industry. However, compared with the rapid growth in LIB consumption, the recycling rate of lithium-ion batteries on the market is less than 5%, and most of the recycling is focused on extracting the valuable metal Co. Due to economic and technological constraints, large-scale lithium recovery processes are currently limited. For example, some technologies use alcohol-water vapor to recover metal elements from the cathode materials of spent lithium batteries. This method requires high temperatures of 350-400°C, consumes a lot of energy, and raises safety issues. Other technologies attempt to recover lithium from spent lithium-ion batteries under negative pressure conditions. However, this method does not fully utilize the transition metal elements and its economic efficiency needs to be improved.

[0007] In summary, in the related technologies for recycling waste lithium-ion batteries, either the metal elements are not fully recovered, or the metal elements are not recovered separately. Summary of the Invention

[0008] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a method for separating Li / Co / Mn / Ni in a solution, which can comprehensively and independently recover Li, Co, Mn and Ni resources in the aqueous solution.

[0009] The present invention also provides applications of the above method.

[0010] According to an embodiment of the first aspect of the present invention, a method for separating Li / Co / Mn / Ni in a solution is provided, the method comprising the following steps:

[0011] S1. Extracting the transition metal ions in the mixed metal solution by an organic phase A containing a composite extractant to obtain a loaded organic phase A and a raffinate phase A;

[0012] The mixed metal solution contains Li, Co, Mn and Ni;

[0013] The composite extractant includes a Primene extractant and Cyanex 272 (CAS: 83411-71-6, also known as Mextral 272P); and the volume ratio of the Primene extractant to Cyanex 272 is ≥1.5; the Primene extractant includes at least one of Primene JM-T (CAS: 68955-54-4) and Primene 81R (CAS: 68955-53-3);

[0014] S2. stripping the loaded organic phase A to obtain stripping phase A;

[0015] S3. Extracting the stripping phase A with an organic phase B containing P204 (CAS: 298-07-7) to obtain a loaded organic phase B and a raffinate phase B;

[0016] S4. Adjust the pH of the raffinate phase B to ≥ 4, and then extract the raffinate phase B with the organic phase C containing Cyanex 272 to obtain a loaded organic phase C and a raffinate phase C.

[0017] The mechanism of the method is as follows:

[0018] In step S1, Co, Mn, and Ni are transferred to the loaded organic phase A, and Li remains in the raffinate phase A, achieving the separation of Li and transition metals;

[0019] In step S2, Co, Mn and Ni are transferred to the stripping phase A;

[0020] In step S3, Mn is transferred to the loaded organic phase B, while Ni and Co remain in the raffinate phase B, thus achieving the separation of Mn and other transition metals;

[0021] In step S4, Co is transferred to the loaded organic phase C, and Ni remains in the raffinate phase C, achieving separation of Ni and Co. This step also shows that Cyanex 272 alone cannot achieve co-extraction of nickel, cobalt, and manganese.

[0022] The method according to the embodiment of the present invention has at least the following beneficial effects:

[0023] (1) The present invention comprehensively and independently recovers Li, Co, Mn and Ni resources in aqueous solution through the setting of steps and the selection of extractants in organic phases A to C.

[0024] (2) The present invention creatively combines Primene extractant, which is used for extraction in other fields, with Cyanex 272, and by limiting the ratio of the two, Co / Mn / Ni can be extracted from the leachate containing Li / Co / Mn / Ni into the organic phase, thereby achieving separation from Li and transition metals. Compared with other types of extractants, it can significantly avoid the extraction of Li and improve the extraction of Co / Mn / Ni, resulting in higher separation efficiency. If the proportion of Primene extractant is lower than the range required by the present invention, the synergistic effect of the two extractants decreases, the extraction rate of Co / Mn / Ni decreases, and the extraction rate of Li increases, making it difficult to achieve separation of transition metals and lithium.

[0025] (3) The present invention further improves the separation efficiency of nickel and cobalt by adjusting the pH of the raffinate phase B in step S4, thereby improving the purity of the final nickel-based product and the cobalt-based product.

[0026] In summary, the method provided by the present invention has the advantages of high extraction rate, strong selectivity, simple process, recyclable extraction agent, low cost, and easy operation.

[0027] According to some embodiments of the present invention, the mixed metal solution satisfies at least one of the following parameters:

[0028] (A) Li 1~2g / L;

[0029] (B) Co 2-3 g / L;

[0030] (C) Mn 3-4.5 g / L;

[0031] (D)Ni 6~7g / L;

[0032] (E) pH 8 to 10. Specifically, it can be about 9.

[0033] If the pH of the mixed metal solution is outside the above range, it is necessary to adjust the pH before implementing the method to facilitate extraction. Specifically, within this range, the organic phase A achieves >99% extraction efficiency for Mn, Co, and Ni, and <10% extraction efficiency for Li. If the pH is too high, hydrolysis and precipitation of transition metal ions may occur.

[0034] According to some embodiments of the present invention, the mixed metal solution is an aqueous solution.

[0035] According to some embodiments of the present invention, the mixed metal solution is a leachate of waste lithium-ion positive electrode materials, or a leachate of minerals.

[0036] According to some embodiments of the present invention, the leachate of the waste lithium-ion positive electrode material is obtained by mixing an acid, a reducing agent, and the waste lithium-ion positive electrode material for leaching.

[0037] The solid-liquid ratio of the mixed leaching is 1g:20-100mL; for example, it can be about 1g:40mL, 1g:50mL or about 1g:60mL; thereby, there is sufficient acid to react with the waste lithium-ion positive electrode material, and within this range, it has the advantages of resource conservation (acid / reducing agent) and easy solid-liquid separation.

[0038] The concentration of the acid used in the mixed leaching is 2 to 4 mol / L; for example, it can be about 3 mol / L or about 3.5 mol / L;

[0039] The acid used in the mixed leaching includes at least one of HCl, H2SO4 and HNO3;

[0040] The reducing agent is hydrogen peroxide, and the concentration is 25-35 vol%, for example, about 28%, 30% or about 32%.

[0041] The volume percentage of the reducing agent to the acid is 5-20%, for example, about 8%, 9%, 10% or about 15%.

[0042] The temperature of the mixed leaching is 25 to 90° C., for example, about 40° C., 60° C., or about 80° C. The increase in temperature increases molecular kinetic energy, accelerates molecular motion, and thus promotes diffusion, which is beneficial to leaching. Furthermore, within this temperature range, the evaporation rate of the water phase used in the mixed leaching is controllable, avoiding the situation where the water phase evaporates to dryness.

[0043] The duration of the mixed leaching is 1 to 2 hours; for example, it can be specifically about 1.5 hours. Studies have found that when the leaching time is about 1 hour, the leaching rate begins to tend to equilibrium. Generally, the leaching amount is proportional to the leaching time, but when the diffusion reaches equilibrium, time no longer plays a role. In order to ensure that the leaching reaction is completely leached, all the metals in the metal powder are leached as much as possible, and all the metals are recovered, the leaching time is 1 hour to 2 hours. Within this time range, the leaching efficiency and production efficiency can be guaranteed, and the leaching of waste can be avoided.

[0044] During the mixed leaching process, Li / Co / Mn / Ni can be converted from a metal oxide state (or other solid form) to an ionic state soluble in water and transferred from the solid to the leachate; the addition of a reducing agent such as hydrogen peroxide helps to reduce the metal and accelerate the mixed leaching process.

[0045] According to some embodiments of the present invention, the waste lithium-ion cathode material includes at least one of lithium cobaltate, lithium nickelate, lithium nickel cobalt manganeseate, lithium nickel cobaltate, and lithium cobalt manganeseate. The ratio of nickel, cobalt, and manganese in the lithium nickel cobalt manganeseate is not strictly limited. In other words, the use of any waste lithium-ion cathode material does not affect the implementation of the method provided by the present invention.

[0046] According to some embodiments of the present invention, in step S1, the volume ratio of Primene extractant to Cyanex 272 in the composite extractant is 1.5 to 9:1, for example, approximately 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, or approximately 8:1. Within this range, the extraction of transition metal elements can be achieved while reducing the extraction of lithium, without causing precipitation that could affect subsequent processes.

[0047] According to some embodiments of the present invention, in step S1, the organic phase A is extracted with an O / A ratio of 0.5 to 5:1, for example, about 1:1, 2:1, 3:1 or about 4:1.

[0048] The O / A ratio is limited to the extraction system with appropriate viscosity and sufficient extractant to meet the requirements of extraction efficiency and extraction rate. The reason for limiting the O / A ratio in other steps is the same.

[0049] According to some embodiments of the present invention, in step S1, the volume percentage of the composite extractant in the organic phase A is 30-100%, and the remainder is a diluent.

[0050] According to some embodiments of the present invention, in step S1, the extraction comprises sequentially performing mixing and phase separation. The mixing duration is 25 to 35 minutes, for example, approximately 30 minutes, and the mixing is performed with mechanical stirring. Phase separation methods include standing and centrifugation. If centrifugation is used, the separation duration is 3 to 8 minutes, for example, approximately 5 minutes.

[0051] According to some embodiments of the present invention, the method further comprises precipitating lithium carbonate from the raffinate phase A.

[0052] The specific process of obtaining lithium carbonate by precipitation is as follows:

[0053] Adjusting the pH of the raffinate phase A to 10-12; for example, it can be adjusted to about 11;

[0054] Then, lithium is precipitated using a saturated carbonate aqueous solution; the carbonate used includes at least one of sodium carbonate and potassium carbonate;

[0055] Then the solid-liquid separation is carried out and the dried lithium carbonate is obtained.

[0056] According to some embodiments of the present invention, in step S2, the aqueous phase used in the stripping is a 1-3 mol / L aqueous acid solution. The acid used is at least one of hydrochloric acid, nitric acid, and sulfuric acid. For example, it can be a 2 mol / L aqueous sulfuric acid solution.

[0057] According to some embodiments of the present invention, in step S2, the O / A value of the back extraction is 0.8 to 1.2:1; for example, it can be about 1:1.

[0058] According to some embodiments of the present invention, in step S2, the back extraction process includes sequentially performing mixing and phase separation. The mixing duration is 10 to 20 minutes, for example, approximately 15 minutes, and the mixing is performed with mechanical stirring. Phase separation methods include standing and centrifugation. If centrifugation is used, the separation duration is 3 to 8 minutes, for example, approximately 5 minutes.

[0059] According to some embodiments of the present invention, step S3 further includes adjusting the pH of the stripping phase A to a range of 3 to 5 before the extraction. Specifically, for example, it can be approximately 4. Within this pH range, after adjusting parameters such as the O / A ratio, the organic phase B, including P204, achieves an extraction rate of >90% for Mn and <5% for Co and Ni, effectively preventing hydrolysis and precipitation of transition metals. Outside this range, Mn cannot be effectively separated. In other words, adjusting the pH of the stripping phase A can further improve the separation efficiency of manganese from cobalt and nickel, thereby increasing the purity of the final manganese-based product.

[0060] According to some embodiments of the present invention, in step S3, the volume concentration of P204 in the organic phase B is 10-30%. For example, it can be approximately 20%. The remainder is diluent. Within this concentration range, P204 can efficiently extract Mn, with an extraction rate ≥95%, while the extraction rates of Co / Ni are both <10%, allowing for the separation of Mn from metallic Co / Ni. Below this range, the extraction rate of Mn is reduced, while above this range, the extraction rate of Co / Ni is increased. In other words, within this range, the separation of Mn from other transition metals is optimal.

[0061] According to some embodiments of the present invention, in step S3, the organic phase B is extracted with an O / A ratio of 0.5 to 5:1, for example, about 1:1, 2:1, 3:1 or about 4:1.

[0062] According to some embodiments of the present invention, in step S3, the extraction process includes sequentially performing mixing and phase separation. The mixing duration is 25 to 35 minutes, for example, approximately 30 minutes, and the mixing is performed with mechanical stirring. Phase separation methods include standing and centrifugation. If centrifugation is used, the separation duration is 3 to 8 minutes, for example, approximately 5 minutes.

[0063] According to some embodiments of the present invention, the method further comprises: stripping the loaded organic phase B to obtain a stripping phase B; and precipitating a manganese salt from the stripping phase B.

[0064] According to some embodiments of the present invention, the aqueous phase used for stripping the loaded organic phase B is a 0.1-3 mol / L aqueous acid solution. Specifically, the concentration can be about 0.5 mol / L, 0.8 mol / L, 1 mol / L, 2 mol / L, or about 2.5 mol / L. Specifically, the acid is at least one of sulfuric acid and nitric acid. For example, the aqueous solution can be about 2 mol / L sulfuric acid.

[0065] According to some embodiments of the present invention, the O / A value of the back extraction of the loaded organic phase B is 0.8 to 1.2:1; for example, it can be specifically about 1:1.

[0066] According to some embodiments of the present invention, stripping the loaded organic phase B comprises sequentially mixing and phase separation. The mixing duration is 10 to 20 minutes, for example, approximately 15 minutes, and the mixing is performed with mechanical stirring. Phase separation methods include standing and centrifugation. If centrifugation is employed, the separation duration is 3 to 8 minutes, for example, approximately 5 minutes.

[0067] According to some embodiments of the present invention, the process of precipitating the manganese salt comprises the following steps:

[0068] Adjusting the pH of the stripping phase B to 7-8; for example, to about 7.5;

[0069] A saturated carbonate aqueous solution is added thereto to obtain a manganese carbonate precipitate. Specifically, the carbonate used includes at least one of sodium carbonate and potassium carbonate.

[0070] According to some embodiments of the present invention, in step S4, the pH of the raffinate phase B after adjustment is between 8 and 11. Specifically, it can be approximately 9, 9.5, or approximately 10. Within this range, the Cyanex 272 extractant has a high Co extraction rate, exceeding 95%. At the optimal volume fraction and pH value, the Cyanex 272 extractant can achieve a Co extraction rate exceeding 99%, while Ni extraction is less than 20%. Lowering the pH will reduce the Co extraction rate to a certain extent. Raising the pH may lead to precipitation of transition metal ions.

[0071] According to some embodiments of the present invention, in step S4, the volume concentration of Cyanex 272 in the organic phase C is 20-100%. The remainder is diluent. Within this range, the Co extraction efficiency of Cyanex 272 is consistently greater than 90%. At the optimal extraction volume, the Co extraction efficiency of Cyanex 272 is consistently ≥95%, while the Ni extraction efficiency is consistently less than 10%, enabling the separation of Co from Ni. However, a volume fraction that is too low results in a reduced Co extraction efficiency of Cyanex 272, making it difficult to separate Co from Ni.

[0072] According to some embodiments of the present invention, in step S4, the volume concentration of Cyanex 272 in the organic phase C is 30-90%, for example, about 40%, 50%, 60%, 70% or about 80%.

[0073] According to some embodiments of the present invention, in step S4, the organic phase C is extracted with an O / A ratio of 0.5 to 5:1, for example, about 1:1, 2:1, 3:1 or about 4:1.

[0074] According to some embodiments of the present invention, in step S4, the extraction comprises sequentially performing mixing and phase separation. The mixing duration is 25 to 35 minutes, for example, 30 minutes, and the mixing is performed with mechanical stirring. Phase separation methods include standing and centrifugation. If centrifugation is used, the separation duration is 3 to 8 minutes, for example, approximately 5 minutes.

[0075] According to some embodiments of the present invention, the method further comprises precipitating nickel salts from the raffinate phase C.

[0076] According to some embodiments of the present invention, the precipitating nickel salt comprises the following steps:

[0077] The pH of the raffinate phase C is adjusted to 8-10, for example, about 9;

[0078] A saturated carbonate aqueous solution is added thereto to precipitate nickel carbonate, wherein the carbonate used comprises at least one of sodium carbonate and potassium carbonate.

[0079] In actual production, the saturated carbonate aqueous solution can be replaced by other reagents that can precipitate nickel as needed.

[0080] According to some embodiments of the present invention, the method further comprises stripping the loaded organic phase C to obtain a stripping phase C, and precipitating a cobalt compound from the stripping phase C.

[0081] According to some embodiments of the present invention, the O / A value of the back extraction of the loaded organic phase C is 0.8 to 1.2:1; for example, it can be specifically about 1:1.

[0082] According to some embodiments of the present invention, the aqueous phase used in the stripping of the loaded organic phase C is a 0.1-3 mol / L aqueous acid solution. The acid used specifically includes at least one of sulfuric acid, hydrochloric acid, and nitric acid. The specific concentration can be about 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, or about 2.5 mol / L.

[0083] More specifically, the aqueous phase used in the back extraction of the loaded organic phase C is a 2-3 mol / L hydrochloric acid aqueous solution.

[0084] Alternatively, the aqueous phase used in the back extraction of the loaded organic phase C is a 0.1-3 mol / L aqueous sulfuric acid solution, and the specific concentration may be about 1 mol / L, 2 mol / L, or about 2.5 mol / L.

[0085] Alternatively, the aqueous phase used in the back extraction of the loaded organic phase C is a 0.1-3 mol / L aqueous nitric acid solution, and the specific concentration may be about 1 mol / L, 2 mol / L, or about 2.5 mol / L.

[0086] According to some embodiments of the present invention, stripping the loaded organic phase C comprises sequentially mixing and phase separation. The mixing duration is 10 to 20 minutes, for example, approximately 15 minutes, and the mixing is performed with mechanical stirring. Phase separation methods include standing and centrifugation. If centrifugation is used, the separation duration is 3 to 8 minutes, for example, approximately 5 minutes.

[0087] According to some embodiments of the present invention, the precipitation of the cobalt compound comprises the following steps:

[0088] The pH of the stripping phase C is adjusted to 10 to 12, for example, about 11;

[0089] A saturated aqueous alkali solution is added thereto to precipitate cobalt hydroxide, wherein the alkali used comprises at least one of sodium hydroxide and potassium hydroxide.

[0090] According to an embodiment of the second aspect of the present invention, there is provided an application of the method described in hydrometallurgy.

[0091] Since the application adopts all the technical solutions of the method of the above embodiment, it has at least all the beneficial effects brought by the technical solutions of the above embodiment.

[0092] According to some embodiments of the present invention, the object of the hydrometallurgy includes at least one of minerals and waste lithium-ion batteries, and is particularly targeted at waste lithium-ion battery positive electrode materials in waste lithium-ion batteries.

[0093] According to an embodiment of the third aspect of the present invention, there is provided an application of the method described in recycling waste lithium batteries.

[0094] Since the application adopts all the technical solutions of the method of the above embodiment, it has at least all the beneficial effects brought by the technical solutions of the above embodiment.

[0095] According to some embodiments of the present invention, the waste lithium battery recycling includes sequentially disassembling and sorting to obtain waste lithium-ion battery positive electrode materials, and leaching the waste lithium-ion battery positive electrode materials, and treating the obtained leachate using the method.

[0096] Unless otherwise specified, the reagent used to adjust the pH in the present invention is at least one of a 2 mol / L sodium hydroxide aqueous solution, a 2 mol / L ammonia aqueous solution, and a 2-4 mol / L hydrochloric acid aqueous solution. If ammonia aqueous solution is used to adjust the pH, it also has a complexing effect, thus preventing the precipitation of transition metal ions at higher pH conditions.

[0097] Unless otherwise specified, the diluent used in the organic phase of the present invention is kerosene, which can improve the physical properties of the organic phase, specifically changing the viscosity, fluidity, and density, increasing the density difference between the organic phase and the aqueous phase, and facilitating phase separation during the extraction / stripping process.

[0098] Unless otherwise specified, the term “about” in the present invention actually means that the error is allowed to be within the range of ±2%, for example, about 100 actually means 100±2%×100.

[0099] Unless otherwise specified, “between” in the present invention includes the number itself, for example, “between 2 and 3” includes the endpoint values ​​2 and 3.

[0100] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0101] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments with reference to the following drawings, in which:

[0102] Figure 1 It is a schematic diagram of the process of embodiment 1 of the present invention. DETAILED DESCRIPTION

[0103] The following will clearly and completely describe the concept and technical effects of the present invention in conjunction with the embodiments to fully understand the purpose, features and effects of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0104] In the description of the present invention, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the exemplary expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0105] Example 1

[0106] refer to Figure 1 This example provides a method for separating Li / Co / Mn / Ni in a solution and applies it to waste lithium batteries, especially the recovery of waste lithium battery positive electrode materials. The specific steps are as follows:

[0107] S1.

[0108] Obtaining a mixed metal solution: 2 g of waste lithium battery cathode material powder was placed in a three-necked flask, and 100 mL of a mixed solution of 3 mol / L HCl and 30% hydrogen peroxide in a volume ratio of 8:100 was added. The mixture was stirred and heated in a constant temperature water bath at 85°C for 2 h for leaching. The reacted solution was filtered to remove the powder to obtain a mixed metal solution. The specific composition is shown in Table 1.

[0109] Table 1 Composition of the mixed metal solution used in Example 1

[0110] Li Co Mn Ni Ion concentration (mg / L) 1471.40 2374.70 3412.28 6204.73

[0111] Extraction of mixed metal solution with organic phase A: Take 10 mL of mixed metal solution, adjust pH to 7 with 2 mol / L NaOH, place in a centrifuge tube, add 10 mL of organic phase A for mixed extraction; wherein,

[0112] The composition of organic phase A was 1.8 mL of Primene JM-T, 1.2 mL of Cyanex 272, and 7 mL of kerosene;

[0113] The mixed extraction process is as follows: Mn / Co / Ni extraction is performed under magnetic stirring at room temperature for 30 minutes. After the extraction, the centrifuge tube is placed in a centrifuge for 5 minutes and then taken out for phase separation to obtain a loaded organic phase A containing Co / Mn / Ni and a raffinate phase A containing Li.

[0114] Lithium precipitation: Take 10 mL of raffinate phase A, adjust its pH to 10 with 2 mol / L NaOH, add saturated Na2CO3 solution and stir to precipitate. After stirring, filter and dry to obtain white Li2CO3 powder;

[0115] S2. Stripping of loaded organic phase A: 10 mL of 1 mol / L H2SO4 was added to the loaded organic phase A and magnetically stirred at room temperature for 15 min for Co / Mn / Ni stripping. After stripping, the centrifuge tube was placed in a centrifuge for 5 min and then removed for phase separation to obtain stripped phase A.

[0116] S3. Extraction of stripping phase A with organic phase B: 10 mL of stripping phase A was adjusted to pH 5 with 2 mol / L NaOH and placed in a centrifuge tube. 10 mL of organic phase B (kerosene as diluent, 30% P204 as extractant by volume) was added. Mn was extracted by magnetic stirring at room temperature for 30 minutes. After extraction, the centrifuge tube was centrifuged for 5 minutes, removed, and phases separated to obtain a raffinate phase B containing Co / Ni and a loaded organic phase B containing Mn.

[0117] Stripping of loaded organic phase B: 10 mL of 0.5 mol / L H2SO4 was added to loaded organic phase B and magnetically stirred at room temperature for 15 min to strip Mn. After stripping, the centrifuge tube was placed in a centrifuge for 5 min and then taken out for phase separation to obtain stripping phase B containing Mn;

[0118] Precipitation of manganese salt: Take 10 mL of stripping phase B, adjust the pH of the aqueous phase to 7 with 2 mol / L NaOH, and add saturated Na2CO3 solution and stir to precipitate. After stirring, filter and dry to obtain a pink-white MnCO3 powder.

[0119] S4. Extraction of raffinate phase B with organic phase C: 10 mL of raffinate phase B was adjusted to pH 8 with 2 mol / L NH3·H2O and placed in a centrifuge tube. 10 mL of organic phase C (kerosene as diluent, 70% Cyanex 272 as extractant) was added and Co was extracted under magnetic stirring at room temperature for 30 min. After extraction, the centrifuge tube was centrifuged for 5 min, removed, and phases separated to obtain raffinate phase C containing Ni and loaded organic phase C containing Co.

[0120] Stripping of loaded organic phase C: 10 mL of 1 mol / L H2SO4 was added to the loaded organic phase C and magnetically stirred at room temperature for 15 min for Co stripping. After stripping, the centrifuge tube was placed in a centrifuge for 5 min and then taken out for phase separation to obtain stripping phase C containing Co.

[0121] Cobalt precipitation: Take 10 mL of stripping phase C, adjust the pH of the aqueous phase to 12 with 2 mol / L NaOH, and add saturated NaOH solution and stir to precipitate. After stirring, filter and dry to obtain rose-red Co(OH)2 powder;

[0122] Nickel precipitation: Take 10 mL of the raffinate phase C, adjust the pH of the aqueous phase to 9 with 2 mol / L NaOH, add a saturated Na2CO3 solution and stir at room temperature for 1 h for precipitation. After stirring, filter and dry to obtain a light green NiCO3 powder.

[0123] Example 2

[0124] This example provides a method for separating Li / Co / Mn / Ni in a solution, and applies it to waste lithium batteries, especially the recovery of waste lithium battery positive electrode materials. The specific steps differ from those in Example 1 in that:

[0125] (1) In step S1, different leaching processes are used, and the composition of the obtained mixed metal solution is different; specifically, as follows:

[0126] Obtaining a mixed metal solution: 2 g of waste lithium battery cathode material powder was placed in a three-necked flask, and 100 mL of a mixed solution of 4 mol / L H2SO4 and 30% hydrogen peroxide was added in a volume ratio of 10:100. The solution was stirred and heated in a constant temperature water bath at 85°C for 2 h for leaching. The reacted solution was filtered to remove the powder to obtain a mixed metal solution. The specific composition is shown in Table 2.

[0127] Table 2 Composition of the mixed metal solution used in Example 2

[0128] Li Co Mn Ni Ion concentration (mg / L) 1585.32 2414.59 4021.72 6535.43

[0129] (2) In step S1, Primene JM-T was replaced with an equal amount of Primene 81R (CAS: 68955-53-3).

[0130] Example 3

[0131] This example provides a method for separating Li / Co / Mn / Ni in a solution, and applies it to waste lithium batteries, especially the recovery of waste lithium battery positive electrode materials. The specific steps differ from those in Example 1 in that:

[0132] (1) In step S1, the ratio of Primene JM-T to Cyanex 272 in organic phase A is different, as follows:

[0133] In step S1, the composition of organic phase A is 2.5 mL of Primene JM-T, 0.5 mL of Cyanex 272 and 7 mL of kerosene.

[0134] Example 4

[0135] This example provides a method for separating Li / Co / Mn / Ni in a solution, and applies it to waste lithium batteries, especially the recovery of waste lithium battery positive electrode materials. The specific steps differ from those in Example 1 in that:

[0136] (1) In step S3, the pH of the stripping phase A is adjusted differently, specifically as follows:

[0137] Extraction of stripping phase A with organic phase B: Take 10 mL of stripping phase A, adjust the pH to 4 with 2 mol / L NaOH, and place it in a centrifuge tube. Add 10 mL of organic phase B (diluent is kerosene, extractant P204 volume fraction is 30%), and magnetically stir at room temperature for 30 minutes to extract Mn. After the extraction is completed, place the centrifuge tube in a centrifuge for 5 minutes, then take it out and separate the phases to obtain the raffinate phase B containing Co / Ni and the loaded organic phase B containing Mn.

[0138] Comparative Example 1

[0139] This example provides a method for separating Li / Co / Mn / Ni in a solution, which differs from Example 1 in that:

[0140] In step S1, the composition of organic phase A is 1 mL Primene JM-T, 2 mL Cyanex 272 and 7 mL kerosene.

[0141] Comparative Example 2

[0142] This example provides a method for separating Li / Co / Mn / Ni in a solution, which differs from Example 1 in that:

[0143] In step S4 , before extracting the raffinate phase B with the organic phase C, the pH of the raffinate phase B is adjusted to 5.

[0144] Comparative Example 3

[0145] This example provides a method for separating Li / Co / Mn / Ni in a solution, which differs from Example 1 in that:

[0146] In step S1, the composition of organic phase A is 3 mL of D2EHPA (CAS: 298-07-7) extractant and 7 mL of kerosene;

[0147] Comparative Example 4

[0148] This example provides a method for separating Li / Co / Mn / Ni in a solution, which differs from Example 1 in that:

[0149] In step S1, the composition of organic phase A is 3 mL of Primene JM-T and 7 mL of kerosene.

[0150] Test Case

[0151] This example tests the quality and purity of lithium carbonate, manganese carbonate, nickel carbonate, and cobalt hydroxide obtained in the Examples and Comparative Examples; and calculates the yields of lithium, nickel, cobalt, and manganese. The purity test method is to dissolve the corresponding solid product, measure the concentration of lithium, nickel, cobalt, or manganese by ICP-OES, and calculate the ratio of this concentration to the theoretical concentration, which is the purity (the purity of the corresponding compound).

[0152] The test results of the above items are shown in Table 3.

[0153] Table 3 Purity of the products obtained in the examples and comparative examples, as well as the yields of lithium, nickel, cobalt and manganese

[0154]

[0155] By comparing the results of Examples 1 to 4, it can be seen that within the scope provided by the present invention, by changing the type, proportion, composition of the mixed metal solution and even some process parameters of the extractant, a product of higher purity can be obtained, and the corresponding metal yield is higher; specifically, the purity of lithium carbonate is ≥99%, which can reach 99.9% in actual production; the yield of lithium is ≥99.0%, which can reach 99.7% or even 99.9% in actual production; the purity of cobalt hydroxide is ≥97%, which can reach 97.5%, 98.0% or even 99% in actual production; the yield of cobalt is ≥98%, which can reach 98.5% or even 99% in actual production; the purity of manganese carbonate is ≥98%, which can reach 98.5% or even 99% in actual production; the yield of manganese is ≥99%, which can reach 99.0% or even 99.9% in actual production; the purity of nickel carbonate is ≥99.0%, which can reach 99.5% in actual production; and the yield of nickel is ≥98.0%, which can reach 98.5% or even 99% in actual production.

[0156] Comparison of Example 1 and Comparative Example 1 reveals that if the proportion of the composite extractant in organic phase A is outside the range required by the present invention, the extraction rate of transition metals in step S1 decreases, particularly nickel, which has almost no extraction performance. Simultaneously, the extraction rate of lithium increases, ultimately reducing the recovery rate of each metal and the purity of the corresponding metal compounds. Most importantly, nickel cannot be isolated.

[0157] By comparing Example 1 and Comparative Example 2, it can be seen that if the pH adjustment in step S4 is not within the range required by the present invention, it has little significant effect on the yield and purity of lithium and manganese, but will significantly affect the separation of nickel and cobalt.

[0158] By comparing Example 1 and Comparative Example 3, it can be seen that if the composite extractant used in the present invention is replaced with a common nickel-cobalt-manganese co-extraction extractant, the resulting effect trend is similar to that of Comparative Example 1. On the one hand, the separation of lithium and transition metals cannot be achieved. On the other hand, in the subsequent stripping and re-extraction, the separation of nickel, cobalt and manganese cannot be effectively achieved.

[0159] Comparison of Example 1 and Comparative Example 4 shows that if the extractant in the organic phase A only includes Primene JM-T, only Co, Mn, Ni and Li can be separated, and Co, Mn and Ni cannot be further extracted and separated.

[0160] It can also be seen from the processes of the embodiments and comparative examples that in the method provided by the present invention, the implementation temperature of all procedures is less than 100° C., and the process is safe, reliable and highly stable.

[0161] In summary, the method provided by the present invention, through the design of steps and parameters, can achieve the separate recovery of Li / Co / Mn / Ni, and the recovered products are of high purity, simple to operate, safe and reliable. Precisely because of these advantages, the method provided by the present invention is expected to be widely used in hydrometallurgy, especially in the recovery of waste lithium-ion batteries.

[0162] While the embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to the embodiments described above. Various modifications may be made within the scope of knowledge possessed by a person skilled in the art without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof may be combined with one another unless there is a conflict.

Claims

1. A method for separating Li / Co / Mn / Ni in a solution, characterized in that: The method comprises the following steps: S1. Extracting the transition metal ions in the mixed metal solution with an organic phase A containing a composite extractant to obtain a loaded organic phase A and a raffinate phase A; precipitating lithium carbonate from the raffinate phase A; The mixed metal solution contains Li, Co, Mn and Ni; The composite extractant includes Primene extractant and Cyanex 272; and the volume ratio of Primene extractant to Cyanex 272 is ≥1.5; the Primene extractant includes at least one of Primene JM-T and Primene 81R; S2. stripping the loaded organic phase A to obtain stripping phase A; S3. Extracting the stripping phase A with an organic phase B containing P204 to obtain a loaded organic phase B and a raffinate phase B; stripping the loaded organic phase B to obtain a stripping phase B; and precipitating a manganese salt from the stripping phase B; S4. The pH of the raffinate phase B is adjusted to 8-11 with aqueous ammonia, and then the raffinate phase B is extracted with an organic phase C containing Cyanex 272 to obtain a loaded organic phase C and a raffinate phase C; nickel salts are precipitated from the raffinate phase C; the loaded organic phase C is stripped to obtain a strip phase C, and a cobalt compound is precipitated from the strip phase C.

2. The method according to claim 1, characterized in that The mixed metal solution satisfies at least one of the following parameters: (A) Li 1~2g / L; (B) Co2~3g / L; (C) Mn3~4.5g / L; (D) Ni6~7g / L; (E) pH8~10.

3. The method according to claim 1, characterized in that In step S1, the organic phase A is extracted with an O / A ratio of 0.5 to 5:1; and / or the volume percentage of the composite extractant in the organic phase A is 30 to 100%.

4. The method according to claim 1, wherein In step S3, the pH of the stripping phase A is adjusted to 3-5 before the extraction; and / or, in step S3, the extraction of the organic phase B is performed with an O / A value of 0.5-5:

1.

5. The method according to claim 1, wherein In step S4, the organic phase C is extracted with an O / A value of 0.5 to 5:

1.

6. Use of the method according to any one of claims 1 to 5 in hydrometallurgy.

7. Use of the method according to any one of claims 1 to 5 in the recycling of waste lithium batteries.

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