Leaching agent and method for selectively leaching metal elements of waste nickel-containing lithium ion battery positive electrode material

Abstract

The invention belongs to the field of waste battery positive electrode material recovery, and particularly relates to a leaching agent and method for selectively leaching metal elements of a waste nickel-containing lithium ion battery positive electrode material, the leaching agent is a mixed solution composed of a component A and a component B with the molar ratio of 1-2: 1, the component A is a compound shown in the formula 1 (# imgabs0 #), the component B is a compound shown in the formula 1 (# imgabs0 #), and the component C is a compound shown in the formula 2 (# imgabs0 #). And the component B comprises a formula 2 (# imgabs 1 #) and a formula 3 (# imgabs 2 #) in a molar ratio of (0.4-3.5): 1. Innovative research shows that through combination of the components from the formula 1 to the formula 3 and combined control of the proportion of the components, synergism can be accidentally achieved, the leaching effect of lithium and other metals can be optimized based on interaction of the components, in addition, accompanying leaching of nickel can be reduced with high selectivity, and the leaching efficiency of lithium and other metals can be improved. In this way, nickel and other metals in the waste battery material can be efficiently and selectively leached and separated.

Description

Technical Field

[0001] The invention belongs to the field of recycling and processing of waste lithium-ion batteries, and relates to the field of leaching of waste positive electrode materials. Background Art

[0002] With the development of the global low-carbon economy, especially the development of the electric vehicle (EV) industry, the demand for lithium-ion batteries has increased significantly, especially ternary lithium-ion batteries with energy density, long cycle life and good safety performance. However, the disposal of waste lithium-ion batteries has attracted more and more attention. In particular, the valuable metals in the positive electrode materials represented by nickel, cobalt, manganese and lithium have limited content and complex extraction process. Direct disposal will cause resource waste and environmental pollution, while improper treatment may cause ecological hazards such as heavy metal leakage. At present, hydrometallurgical processes have become the first choice due to their high recovery rate and effective metal separation of waste batteries. However, this technology usually requires a large amount of strong acid, and the metal separation process involves multiple extraction stages, resulting in serious secondary pollution and lengthy work processes. With the increasing pressure on resources and increasingly stringent environmental standards, it has become a top priority to develop more efficient and environmentally friendly recycling technologies.

[0003] At present, the recovery methods of metal elements of waste battery positive electrode materials are mainly acid leaching, alkaline leaching and other methods, among which acid leaching can achieve full leaching of metals, but the selectivity is not ideal, and the alkaline leaching process mainly involves the pre-extraction of lithium, and transition metals are difficult to leach and recover. In addition, with the continuous development of technology, there are also some schemes of leaching using hydrogen bond system solvents in the prior art. For example, the Chinese patent document with publication number CN113871744A discloses a method for recovering waste lithium ion battery positive electrode active materials, and specifically reports the use of a leaching system containing ethylene glycol and a solution formed by dihydrate formula 2, which can achieve the co-leaching of lithium and nickel, cobalt and manganese. For another example, the Chinese patent document with publication number CN115692908A discloses a method for recovering waste lithium battery positive electrode active materials, specifically discloses a method of obtaining a leaching solution containing only lithium under an ozone atmosphere using formula 1 and ethylene glycol as a leaching system, which also achieves full leaching of metal elements.

[0004] In summary, although there are some improved waste battery metal processes in the prior art, the existing process uses a high amount of leaching agent, and it is difficult to reasonably balance the selectivity and leaching rate between metals, especially transition metals, in the leaching stage. For example, for waste nickel-containing lithium-ion battery positive electrode materials, the existing technology still finds it difficult to achieve efficient and selective leaching of nickel and other metal elements therein. Summary of the invention

[0005] In view of the problem that it is difficult to achieve selective leaching of Ni and other elements in the existing leaching process of waste nickel-containing lithium-ion battery positive electrode materials, the first purpose of the present invention is to provide a leaching agent for selective leaching of metal elements in waste nickel-containing lithium-ion battery positive electrode materials, aiming to achieve efficient selective leaching and separation of nickel and other metals in waste nickel-containing lithium-ion battery positive electrode materials based on the combination of components.

[0006] The second object of the present invention is to provide a method for selectively leaching metal elements from waste nickel-containing lithium-ion battery positive electrode materials, aiming to achieve efficient separation of nickel and other metals with high efficiency and selectivity.

[0007] A leaching agent for selectively leaching metal elements of waste nickel-containing lithium-ion battery positive electrode materials, which is a mixed solution composed of component A and component B in a molar ratio of 1 to 2:1, wherein component A is a compound of formula 1; component B is a compound of formula 2 and formula 3 in a molar ratio of 0.4 to 3.5:1; Formula 1 Formula 2 Formula 3 The R is H or a C1~C3 alkyl group.

[0008] Due to long-term circulation, the surface of the waste positive electrode of the waste battery has a dense SEI component, and the metal element lattices therein are interlocked, which makes leaching difficult, especially the transition metals therein, which are difficult to achieve selective leaching, and it is even more difficult to achieve high-selective leaching and separation of nickel and other components under mild and low leaching agent dosage. In response to this problem, the innovative research of the present invention shows that by combining the components of formula 1 to formula 3, and further co-controlling the proportions of the three, unexpected synergy can be achieved, and the leaching effect of lithium and other metals can be optimized based on the interaction of the three. In addition, the accompanying leaching of nickel can be highly selectively reduced, so that efficient selective leaching and separation of nickel and other metals in waste battery materials can be achieved.

[0009] The present invention shows that the combination of Formula 1 to Formula 3 and the joint control of the component ratio are the key to synergistically adapting the physical and chemical characteristics of waste battery materials and achieving selective separation of nickel and other metal elements therein.

[0010] Furthermore, in Formula 3 of the present invention, the R may be a methyl group or an ethyl group, and the position of R may be the para position of the sulfonic acid group.

[0011] Further preferably, in the component B, the molar ratio of formula 2 to formula 3 is 1 to 3:1; preferably 1.5 to 2.5:1. The present invention also shows that the combined control of the ratio of formula 2 to formula 3 in component B can further optimize the adaptability of the prepared leaching agent to the lattice of the waste battery positive electrode material, which helps to further improve the leaching efficiency and selectivity of nickel and other metal elements.

[0012] Preferably, the molar ratio of component A to component B is 1.4-1.6:1.

[0013] The leaching agent of the present invention is a uniform clear solution formed by hydrogen bonding between Formulas 1 to 3, which can be prepared by heating and stirring the components A and B at 50 to 90°C.

[0014] The present invention also provides a method for selectively leaching metal elements from waste nickel-containing lithium-ion battery positive electrode materials, comprising mixing the waste nickel-containing lithium-ion battery positive electrode materials and the leaching agent for leaching treatment, followed by solid-liquid separation; obtaining leaching residues enriched with nickel elements in the waste nickel-containing lithium-ion battery positive electrode materials and leaching solutions containing other metal elements; the other metal elements at least contain lithium.

[0015] The research of the present invention shows that the leaching agent can adapt to the lattice characteristics of the waste positive electrode material, and can achieve highly selective separation of nickel and other metals with high efficiency and selectivity, especially it can take into account the leaching efficiency and selectivity of nickel and other metal components at a low leaching solvent dosage.

[0016] In the present invention, the waste nickel-containing lithium-ion battery positive electrode material can be a material obtained by stripping the positive electrode of any waste lithium-ion battery containing nickel; it contains waste positive electrode active material and is also allowed to contain components such as a binder, a conductive agent, and a binder.

[0017] In the present invention, the other metal elements in the waste nickel-containing lithium-ion battery positive electrode material are also allowed to include at least one of cobalt and manganese. For example, the positive electrode active material contained in the waste nickel-containing lithium-ion battery positive electrode material can be at least one of a nickel-cobalt binary material, a nickel-manganese binary material, and a nickel-cobalt-manganese ternary material.

[0018] In the present invention, the liquid-to-solid ratio in the leaching stage is 5-20 g / g, preferably 8-12 g / g.

[0019] In the present invention, the temperature in the leaching stage is 20°C or higher, preferably 70 to 90°C.

[0020] In the present invention, the leaching time is 0.5 h or longer, preferably 1 to 10 h, and further can be 4 to 6 h.

[0021] In the present invention, solid-liquid separation is performed directly after leaching is completed or solid-liquid separation is performed after dilution with a polar aprotic solvent. Studies of the present invention show that the use of a polar aprotic solvent can cooperate with the leaching agent to further optimize the leaching selectivity of nickel and other components.

[0022] In the present invention, the polar aprotic solvent includes at least one of dimethyl sulfoxide and N,N-dimethylacetamide.

[0023] In the present invention, based on the waste nickel-containing lithium ion battery positive electrode material, the amount of polar aprotic solvent used is 8-20 mL / g.

[0024] In the present invention, the solid-liquid separation method may be known, such as filtration or centrifugation.

[0025] Beneficial effects: The innovative research of the present invention shows that by combining the components of formula 1 to formula 3, and further coordinating the joint control of the proportions of the three, it is possible to unexpectedly achieve synergy, and based on the interaction of the three, the leaching effect of lithium and other metals can be optimized. Specifically, formula 3 will exclude formula 2 from the nanostructure in the nanostructure formed by the solvent to reduce the consumption of formula 2 during the leaching process, ensuring a stronger ability to selectively precipitate nickel. And formula 3 can bring more hydrogen bonds to the nanostructure, and improve the reducibility of the ternary leaching agent solvent by providing a dominant reduction site, thereby achieving a stronger metal leaching ability. In short, the leaching agent described in the present invention can adapt to the physicochemical characteristics of the positive electrode of the waste battery, and can also achieve selective leaching and separation of nickel and other metals. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The infrared spectra of the components of Example 1 and the mixed leaching agent are shown in FIG. Figure 2 The leaching effect diagram of different temperatures in Example 3, wherein a is the leaching rate of lithium, nickel, cobalt and manganese of the leaching agent at different temperatures; b is the purity of nickel slag precipitated at different temperatures; Figure 3 The leaching effect diagram of different leaching liquid-solid ratios in Example 4, wherein a is the leaching rate of lithium, nickel, cobalt and manganese of the leaching agent at different mass ratios; b is the purity of the precipitated nickel slag at different mass ratios; Figure 4 The leaching rate diagram at different times of Example 5; Figure 5 This is the leaching rate diagram of different components B in comparative example 3. Specific implementation plan

[0027] The present invention is further described in detail below in conjunction with examples and drawings, but the embodiments of the present invention are not limited thereto.

[0028] The waste positive electrode material of the present invention is waste ternary lithium ion battery positive electrode material (LiNi x Co y Mn 1-x-y O2) as an example, which specifically includes LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, LiNi 0.5 Co 0.2 Mn 0.3 O2, LiNi 0.6 Co 0.2 Mn 0.2 O2, LiNi 0.8 Co 0.1 Mn 0.1 O2, and the actual cathode powder obtained by disassembling ternary lithium-ion batteries. In the following cases, unless otherwise stated, LiNi 0.8 Co 0.1 Mn 0.1 O2 ternary active materials are a typical example.

[0029]

[0030] Unless otherwise defined, all the professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0031] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0032] Embodiment 1: Step 1. Preparation of leaching agent: Formula 2 and Formula 3 (R is a methyl group and the compound of Formula 3 is located at the para position of the sulfonic acid group) are mixed in a molar ratio of 7:3 to obtain component B. Component A and component B are mixed in a flask in a molar ratio of 3:2 and heated and stirred at 60-70°C until clarified to form a leaching agent.

[0033] like Figure 1 As shown, the hydroxyl stretching vibration peaks of Formula 1, Formula 2, and Formula 3A are located at 3225 cm -1 , 3486cm -1 ,3426 cm -1 The synthetic leachant has only one ion at 3330 cm -1The large hydroxyl stretching vibration peak at , which means that Formula 1, Formula 2, and Formula 3A synthesized deep eutectic leachants under the action of hydrogen bonding.

[0034] Step 2. Leaching experiment: waste ternary lithium-ion battery positive electrode material (LiNi 0.8 Co 0.1 Mn 0.1 O2) was mixed with a leaching agent in a mass ratio of 1:10, and heated and stirred at 70°C in a water bath for 6 h for leaching; Step 3. Separation experiment: After the leaching in step (2) is completed, a non-polar solvent (dimethyl sulfoxide, the liquid-to-solid ratio of which to the waste positive electrode material is 10-12 mL / g) is added for dilution and then centrifuged to obtain a valuable metal leaching solution containing lithium, manganese, cobalt, etc. and a nickel slag precipitate.

[0035] Step 4. After diluting the valuable metal leachate with water, the concentrations of lithium, manganese, cobalt and nickel therein were determined using an inductively coupled plasma emission spectrometer, and the leaching rates of lithium, manganese, cobalt and nickel were calculated using the valuable metal leaching rate calculation formula, and the results are shown in Table 2. The contents of lithium, manganese, cobalt and nickel in the precipitate were determined after digestion of the nickel slag precipitate and recorded as the purity of the nickel slag, and the results are shown in Table 3.

[0036]

[0037] Embodiment 2: Compared with Example 1, the only difference is that the molar ratio of Formula 2 and Formula 3A in Component B is changed, and the experimental groups are respectively: Group A: The molar ratio of Formula 2: Formula 3A is 5:5; Group B: The molar ratio of Formula 2: Formula 3A is 3:7; The total molar amount of additive B is the same as in Example 1, and other operations and parameters are the same as in Example 1; The leaching effects of each group are shown in Table 4:

[0038] It can be seen from Examples 1 and 2 that the combined control of the ratio of Formula 2 and Formula 3 in Component B can optimize the adaptation effect of the leaching agent to the waste positive electrode material, and can further improve the leaching selectivity of nickel and other elements at a low leaching liquid-to-solid ratio.

[0039] Embodiment 3: Compared with Example 1, the only difference is that the leaching temperature in step 2 is changed to 20°C, 30°C, 50°C, 70°C, 80°C, and 90°C. The leaching results are as follows: Figure 2As shown in the figure, when the leaching temperature is 70°C, the leaching efficiency of lithium, manganese and cobalt can reach 97.59%, 95.84% and 96.77%, and the purity of the obtained nickel slag is 95.7%. When the temperature is further increased to 90°C, the leaching efficiency of lithium, manganese and cobalt reaches 99.12%, 98.44% and 98.11%, and the purity of the obtained nickel slag is as high as 97.4%.

[0040] Embodiment 4: Compared with Example 1, the only difference is that the waste ternary lithium ion battery positive electrode material (LiNi x Co y Mn 1-x-y The mass ratios of O2) to leaching agent are 1:5, 1:8, 1:10, 1:12 and 1:15 respectively.

[0041] like Figure 3 As shown in the figure, even when the mass ratio is 1:8, the leaching efficiency of lithium, manganese and cobalt can still reach 82.98%, 79.23% and 91.72%, and the purity of the obtained nickel slag is 90.13%. With the increase of the solid-liquid ratio, the leaching efficiency and the purity of the nickel slag will be greatly improved.

[0042] Embodiment 5: Compared with Example 1, the only difference is that the leaching time of step 2 is changed to 10 min, 30 min, 1 h, 2 h, 4 h, and 6 h, respectively. Figure 4 As shown, the leaching efficiencies of lithium, manganese and cobalt can reach 81.42%, 72.46% and 78.54% within one hour.

[0043] Embodiment 6: Compared with Example 1, the only difference is that the positive electrode materials and conditions used in step 2 are changed, including LiNi 1 / 3Co 1 / 3 Mn 1 / 3 O2, LiNi 0.5 Co 0.2 Mn 0.3 O2, LiNi 0.6 Co 0.2 Mn 0.2 O2, and the actual positive electrode powder obtained by disassembling the ternary lithium-ion battery. The results are shown in Tables 5 and 6. The synthesized new leaching agent can have a good treatment effect on different types of battery materials, and the leaching rates of lithium, manganese and cobalt are close to 90%.

[0044]

[0045]

[0046] Embodiment 7: Compared with Example 1, the only difference is that the diluent in step 3 is changed to dimethyl sulfoxide and N,N-dimethylacetamide. The results are shown in Table 4. When and only when the diluent is a polar aprotic solvent, it can act as a good diluent without affecting the separation effect of the leachate and the precipitated nickel slag.

[0047]

[0048] Comparative Example 1: Compared with Example 1, the only difference is that in step 1, when preparing the leaching agent solvent, component B is only Formula 2, component A is Formula 1, and the molar ratio of component A to component B is 3:2. Other operations and parameters are the same as Example 11. The concentrations of lithium ions, nickel ions, cobalt ions, and manganese ions contained therein are measured, and the leaching rate is calculated (see Table 8). Compared with the leaching performance of the new leaching agent invented by us, it is far different.

[0049]

[0050] Comparative Example 2: Compared with Example 1, the only difference is that in step 1, when preparing the leaching agent solvent, component B is only Formula 3A, component A is Formula 1, and the molar ratio of component A to component B is 3:2. Other operations and parameters are the same as Example 11. The concentrations of lithium ions, nickel ions, cobalt ions, and manganese ions contained therein are measured, and the leaching rate is calculated (see Table 9). Although this example has a major breakthrough in leaching performance, it cannot achieve the selective precipitation of nickel by the leaching agent invented by us.

[0051]

[0052] Comparative Example 3: Compared with Example 1, the only difference is that the following components (Formulas 4-8) are used to replace Formula 3A described in Component B in equal molar amounts to obtain comparative components B (specific groups are component B groups of Formula 2+Formula 4, component B groups of Formula 2+Formula 5, component B groups of Formula 2+Formula 6, component B groups of Formula 2+Formula 7, and component B groups of Formula 2+Formula 8), and then the comparative components B and component A are fused to obtain comparative leaching agents. Other operations and parameters are the same as in Example 1. The results are shown in Figure 5 If and only if Formula 3A can efficiently leach lithium, manganese, and cobalt at a high solid-to-liquid ratio and low temperature, and selectively precipitate nickel.

[0053] Formula 4 Formula 5 Formula 6 Formula 7 Formula 8 In summary, the innovative research of the present invention shows that the leaching agent of the invention can achieve efficient leaching of valuable metals in waste ternary lithium-ion batteries under mild conditions of low temperature and high solid-liquid ratio, and selectively precipitate nickel at the same time. In addition, the present invention has good applicability to a variety of non-ternary lithium-ion batteries.

[0054] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A leaching agent for selectively leaching metal elements from waste nickel-containing lithium-ion battery positive electrode materials, characterized in that: A mixed solution composed of component A and component B in a molar ratio of 1 to 2:1, wherein component A is a compound of formula 1; component B is a compound of formula 2 and formula 3 in a molar ratio of 0.4 to 3.5:1; Formula 1; Formula 2; Formula 3; The R is H or a C1~C3 alkyl group.

2. The leaching agent according to claim 1, characterized in that In the component B, the molar ratio of formula 2 to formula 3 is 1-3:1, preferably 1.5-2.5:

1.

3. The leaching agent according to claim 1 or 2, characterized in that The molar ratio of component A to component B is 1.4 to 1.6:

1.

4. A method for selectively leaching metal elements from waste nickel-containing lithium-ion battery positive electrode materials, characterized in that: The waste nickel-containing lithium-ion battery positive electrode material and the leaching agent according to any one of claims 1 to 3 are mixed for leaching treatment, followed by solid-liquid separation; leaching residues enriched with nickel elements in the waste nickel-containing lithium-ion battery positive electrode material and leaching liquids of other metal elements are obtained; the other metal elements at least include lithium.

5. The method according to claim 4, characterized in that The other metal elements further include at least one of cobalt and manganese; Preferably, the positive electrode active material contained in the waste nickel-containing lithium-ion battery positive electrode material is at least one of a nickel-cobalt binary material, a nickel-manganese binary material, and a nickel-cobalt-manganese ternary material.

6. The method according to claim 4, characterized in that The liquid-to-solid ratio in the leaching stage is 5-20 g / g, preferably 8-12 g / g.

7. The method according to claim 4, characterized in that The temperature in the leaching stage is 20°C or higher, preferably 70 to 90°C.

8. The method according to claim 4, characterized in that After leaching is completed, solid-liquid separation is carried out directly or after dilution with a polar aprotic solvent, solid-liquid separation is carried out.

9. The method according to claim 8, characterized in that The polar aprotic solvent includes at least one of dimethyl sulfoxide and N,N-dimethylacetamide.

10. The method according to claim 9, characterized in that Based on the waste nickel-containing lithium-ion battery positive electrode material, the amount of polar aprotic solvent used is 8-20 mL / g.

Images