Method for recycling waste lithium ion battery

Abstract

The invention provides a waste lithium ion battery recovery method, which comprises: carrying out copper separation on a battery negative electrode to obtain negative electrode carbon powder and copper powder; mixing the battery positive electrode powder, the negative electrode carbon powder, the spodumene and the carbon source to obtain a mixture, and performing ball milling on the mixture to obtain a ball-milled mixture; the ball-milled mixture is sequentially activated, calcined and leached, and a lithium-containing solution, a nickel-cobalt-manganese-containing solution and silicon slag are obtained through leaching; and preparing the CuOx / SiO2 catalyst by using the copper powder and the silicon slag. According to the method, Li elements in the battery positive electrode and spodumene, Ni, Co and Mn elements in the battery positive electrode and the battery negative electrode can be jointly recycled, meanwhile, Cu resources and Si elements can be used for preparing the catalyst, full recycling of waste resources is achieved, and the method is environmentally friendly.

Description

Technical Field

[0001] The invention relates to the technical field of battery resource recycling, and in particular to a method for recycling waste lithium-ion batteries. Background Art

[0002] There are many reasons for the failure of lithium-ion batteries. The main reason is that during repeated charging and discharging, the positive electrode material and the current collector are partially separated, resulting in poor contact. In addition, the positive electrode material undergoes secondary reactions during the charging and discharging process, which prevents lithium ions from being freely embedded in and out of the crystal structure, thereby causing capacity decay.

[0003] Since the positive electrode materials of lithium-ion batteries are mostly transition metal oxides, which contain precious metals such as cobalt, nickel, and lithium, recycling these precious metals is not only beneficial to environmental protection but also conducive to the comprehensive utilization of resources.

[0004] At present, there are two main methods for recycling power batteries: the first is secondary utilization, that is, cascade utilization. That is, for batteries that have not been scrapped but have reduced capacity and cannot be used in electric vehicles, the batteries are unpacked and packaged in modules, the modules are tested and screened, and then the usable batteries are reassembled and used, such as downgrading or using them in the field of energy storage; the second method is to crush and disassemble the scrapped power lithium batteries, recover the usable materials in them, and achieve the purpose of recycling.

[0005] It is predicted that the amount of retired ternary power lithium-ion batteries will increase. Ternary power lithium-ion batteries contain a large amount of valuable metals. Usually, Co accounts for 5% to 20%, Ni accounts for 5% to 12%, Mn accounts for 7% to 10%, and Li accounts for 2% to 5%.

[0006] Therefore, the resource recycling technology of waste ternary lithium-ion batteries has important significance and practical value. Summary of the invention

[0007] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for recycling waste lithium-ion batteries that can simultaneously realize the joint recovery of the battery positive electrode, negative electrode and spodumene, and the recovery rate of each component is high and the application prospect is broad.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] The invention provides a method for recycling waste lithium-ion batteries, the method comprising: separating the battery negative electrode through copper to obtain negative electrode carbon powder and copper powder; mixing the battery positive electrode powder, negative electrode carbon powder, spodumene and a carbon source to obtain a mixture, and ball milling the mixture to obtain a ball-milled mixture; activating, calcining and leaching the ball-milled mixture in sequence, and the leaching obtains a lithium-containing solution, a nickel-cobalt-manganese-containing solution and silicon slag; preparing CuO by using the copper powder and the silicon slagx / SiO2 catalyst.

[0010] The technical principle of the present invention is as follows:

[0011] Firstly, a carbon source is added in the present invention. The carbon source is fully and evenly mixed with the battery positive electrode powder material. The mixture is calcined, and carbothermal reduction occurs during this process to enhance the reduction effect. The specific chemical equations are as follows:

[0012] 2LiCoO2 + C == Li2CO3 + CoO + Co;

[0013] 2LiCoO2 + CO == Li2CO3 + 2CoO.

[0014] Secondly, the activity and reducibility of Al in the battery positive electrode powder material are fully utilized in the present invention. Spodumene will fully react with the aluminum in the battery positive electrode powder material under high-temperature conditions to generate water-soluble Li2O, and the following reaction occurs: 2LiAl[Si2O6] + 16 / 3Al == Li2O + 4Si + 11 / 3Al2O3, realizing the recycling of aluminum in the waste lithium-ion battery positive electrode. Moreover, the generated lithium oxide can be directly leached, with low consumption of auxiliary materials; furthermore, Li can be directly recovered by water leaching. The recovery value of Al and negative electrode carbon powder in the waste battery positive electrode is low and can be directly not separated and used as a reducing agent, realizing the resource utilization of waste aluminum foil.

[0015] In summary, in the present invention, the mixture obtained by directly mixing the battery positive electrode powder material, negative electrode carbon powder, spodumene, and carbon source is successively ball-milled, activated, and calcined. The calcined material can achieve the efficient leaching of lithium, cobalt, manganese, and nickel through leaching. At the same time, the silicon slag obtained by leaching can be jointly used with the copper of the battery negative electrode to prepare a catalyst, realizing the combined recovery treatment of the positive and negative electrodes and spodumene in the battery, with high resource utilization efficiency.

[0016] The battery negative electrode in the present invention includes a ternary lithium-ion battery negative electrode and / or a lithium cobalt oxide battery negative electrode.

[0017] The battery positive electrode powder material in the present invention includes a ternary lithium-ion battery positive electrode powder material and / or a lithium cobalt oxide battery positive electrode powder material.

[0018] CuO in the present invention x In the / SiO2 catalyst, the copper oxide is generally a mixture of cuprous oxide and copper oxide, that is, the value range of x is 0.5 to 1, for example, it can be 0.5, 0.6, 0.7, 0.8, 0.9, or 1, etc.

[0019] Preferably, the copper separation includes: the battery negative electrode is successively disassembled, first broken, and sorted to obtain negative electrode carbon powder and copper powder.

[0020] Preferably, the first crushing is to crush to 20-80 mesh, for example, it can be 20 mesh, 30 mesh, 40 mesh, 50 mesh, 60 mesh, 63 mesh, 65 mesh, 67 mesh, 69 mesh, 72 mesh, 74 mesh, 76 mesh, 78 mesh or 80 mesh, etc., but not limited to the listed values, and other unlisted values within this range are equally applicable.

[0021] Preferably, the preparation of the battery positive electrode powder includes: the battery positive electrode is subjected to a second crushing to obtain the battery positive electrode powder.

[0022] Preferably, the second crushing is to crush to 60-80 mesh, for example, it can be 60 mesh, 63 mesh, 65 mesh, 67 mesh, 69 mesh, 72 mesh, 74 mesh, 76 mesh, 78 mesh or 80 mesh, etc., but not limited to the listed values, and other unlisted values within this range are equally applicable.

[0023] Preferably, the mass ratio of the battery positive electrode powder to the negative carbon powder is (2-3):1, for example, it can be 2:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1 or 3:1, etc., but not limited to the listed values, and other unlisted values within this range are equally applicable.

[0024] Preferably, the mass ratio of the battery positive electrode powder to spodumene is (2-3):1, for example, it can be 2:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.8:1, 2.9:1 or 3:1, etc., but not limited to the listed values, and other unlisted values within this range are equally applicable.

[0025] The present invention preferably controls the mass ratio of spodumene to the battery positive electrode powder within the above range. On the one hand, it can ensure the sufficient reaction between aluminum in the battery positive electrode powder and spodumene, improving the utilization rate of aluminum resources; on the other hand, it can improve the leaching rate of lithium in water leaching by effectively ensuring the reaction effect of spodumene in the subsequent first calcination process.

[0026] Preferably, the mass ratio of the carbon source to spodumene is (2-4):1, for example, it can be 2:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.8:1, 2.9:1, 3.0:1, 3.2:1, 3.5:1, 3.8:1, 3.9:1 or 4.0:1, etc., but not limited to the listed values, and other unlisted values within this range are equally applicable.

[0027] The present invention preferably controls the mass ratio of the carbon source to spodumene within the above range, which can ensure the full reduction of the positive electrode material, improve the leaching rate of lithium, and effectively avoid a large amount of insoluble substances carried in the acid leaching residue.

[0028] Preferably, the carbon source is anthracite.

[0029] The preferred carbon source in the present invention: anthracite, is a kind of hard, dense and highly lustrous coal variety. Anthracite has a high hardness and can be fully and evenly mixed with the cathode powder of the battery during the ball milling process. It can use its own hardness to fully grind the cathode powder of the battery.

[0030] Moreover, the present invention preferably uses anthracite as a supplementary carbon source. Anthracite has a high carbon content, good reduction performance, and low impurity content, which can reduce the organic matter residue. Anthracite is fully and evenly mixed with the cathode powder of the battery. During the calcination process of the mixture, carbothermal reduction can occur, and the addition of anthracite can strengthen the reduction effect.

[0031] Preferably, the rotation speed of the ball milling is 90 - 180 r / min. For example, it can be 90 r / min, 100 r / min, 110 r / min, 120 r / min, 130 r / min, 140 r / min, 150 r / min, 160 r / min, 170 r / min or 180 r / min, etc., but not limited to the listed values. Other unlisted values within this range are equally applicable.

[0032] Preferably, the time of the ball milling is 30 - 150 min. For example, it can be 30 min, 44 min, 57 min, 70 min, 84 min, 97 min, 110 min, 124 min, 137 min or 150 min, etc., but not limited to the listed values. Other unlisted values within this range are equally applicable.

[0033] Preferably, the mass ratio of the abrasive to the mixture during the ball milling is (1 - 1.5):1. For example, it can be 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1 or 1.5:1, etc., but not limited to the listed values. Other unlisted values within this range are equally applicable.

[0034] Preferably, the abrasive for the ball milling includes any one or a combination of at least two of brown fused alumina, white fused alumina or zirconium fused alumina. Among them, typical but non-limiting combinations are the combination of brown fused alumina and white fused alumina, the combination of zirconium fused alumina and white fused alumina, and the combination of brown fused alumina and zirconium fused alumina.

[0035] Preferably, the activation includes: mixing the ball-milled mixture and an activator, and performing ball milling activation treatment.

[0036] Preferably, the activator includes an alkali solution, preferably a sodium hydroxide solution.

[0037] In the present invention, it is preferably to use sodium hydroxide solution for activation treatment, which can destroy the surface alumina film of the aluminum foil of the positive electrode of the lithium-ion battery, and is beneficial to the aluminothermic reduction reaction after pretreatment. Moreover, after the aluminum foil is activated by the sodium hydroxide solution, moisture is also introduced into the reaction system; the activated material obtained after the ball milling activation treatment contains both moisture and the solid phase of the ball mill mixture. Initially, it is a co-calcination process of liquid and solid. As the calcination progresses, the moisture phase-changes into gas phase, and at the same time, CO and H2 gases are generated, forming a multiphase reaction process of solid, liquid and gas. The following reactions will occur among the moisture, the added anthracite and the negative electrode carbon powder during the calcination process: C(s)+H2O(g)==CO(g)+H2(g), thus generating CO and H2, and both CO and H2 gases will react with the positive electrode powder of the battery, accelerating the reduction reaction and having a high reaction rate.

[0038] Preferably, the alkali concentration of the alkali solution is 2-8 mol / L. For example, it can be 2 mol / L, 2.7 mol / L, 3.4 mol / L, 4 mol / L, 4.7 mol / L, 5.4 mol / L, 6 mol / L, 6.7 mol / L, 7.4 mol / L or 8 mol / L, etc., but is not limited to the listed values, and other unlisted values within this range are equally applicable.

[0039] Preferably, the temperature of the ball milling activation treatment is 80-90 °C. For example, it can be 80 °C, 82 °C, 83 °C, 84 °C, 85 °C, 86 °C, 87 °C, 88 °C, 89 °C or 90 °C, etc., but is not limited to the listed values, and other unlisted values within this range are equally applicable.

[0040] Preferably, the liquid-solid ratio of the activator to the ball mill mixture is (1-2) mL:1 g. For example, it can be 1 mL:1 g, 1.2 mL:1 g, 1.3 mL:1 g, 1.4 mL:1 g, 1.5 mL:1 g, 1.6 mL:1 g, 1.7 mL:1 g, 1.8 mL:1 g, 1.9 mL:1 g or 2 mL:1 g, etc., but is not limited to the listed values, and other unlisted values within this range are equally applicable.

[0041] Preferably, the mass ratio of the balls to the material in the ball milling activation treatment is (1-2):1. For example, it can be 1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1 or 2:1, etc., but is not limited to the listed values, and other unlisted values within this range are equally applicable.

[0042] Preferably, the rotation speed of the ball milling activation treatment is 60 - 180 r / min. For example, it can be 60 r / min, 70 r / min, 80 r / min, 90 r / min, 100 r / min, 110 r / min, 120 r / min, 130 r / min, 140 r / min, 150 r / min, 160 r / min, 170 r / min or 180 r / min, etc., but not limited to the listed values. Other unlisted values within this range are equally applicable.

[0043] Preferably, the time of the ball milling activation treatment is 90 - 120 min. For example, it can be 90 min, 94 min, 97 min, 100 min, 104 min, 105 min, 110 min, 114 min, 115 min or 120 min, etc., but not limited to the listed values. Other unlisted values within this range are equally applicable.

[0044] Preferably, the calcination includes two - stage calcination, namely the first calcination and the second calcination.

[0045] Preferably, the temperature of the first calcination is 900 - 1100 °C. For example, it can be 900 °C, 920 °C, 945 °C, 960 °C, 980 °C, 1010 °C, 1030 °C, 1050 °C, 1070 °C or 1100 °C, etc., but not limited to the listed values. Other unlisted values within this range are equally applicable. The time is 60 - 120 min. For example, it can be 60 min, 64 min, 67 min, 70 min, 74 min, 77 min, 80 min, 84 min, 87 min, 90 min, 100 min, 105 min, 110 min, 115 min or 120 min, etc., but not limited to the listed values. Other unlisted values within this range are equally applicable.

[0046] In the process of the first calcination of the present invention, spodumene will fully react with the aluminum powder on the cathode powder of the battery at high temperature to generate water - soluble Li2O, and the following reactions occur:

[0047] 2LiAl[Si2O6]+16 / 3Al == Li2O + 4Si + 11 / 3Al2O3, Si + O2 == SiO2.

[0048] And under the temperature condition of the first calcination, the following reactions will occur:

[0049] 2LiCoO2 + C == Li2CO3 + CoO + Co;

[0050] C(s)+H2O(g) == CO(g)+H2(g);

[0051] 2LiCoO2 + CO == Li2CO3 + 2CoO。

[0052] Preferably, the temperature of the second calcination is 1100 - 1350 °C but not including 1100 °C. For example, it can be 1110 °C, 1120 °C, 1150 °C, 1180 °C, 1212 °C, 1230 °C, 1260 °C, 1295 °C, 1320 °C or 1350 °C, etc., but not limited to the listed values. Other unlisted values within this range are equally applicable. The time is 30 - 60 min. For example, it can be 30 min, 34 min, 37 min, 40 min, 44 min, 47 min, 50 min, 54 min, 57 min or 60 min, etc., but not limited to the listed values. Other unlisted values within this range are equally applicable.

[0053] In the second calcination process of the present invention, the reaction Li2CO3 == CO2↑ + Li2O occurs, that is, the lithium carbonate generated in the first calcination will decompose into Li2O, and the generated lithium oxide can be directly subjected to water leaching to achieve the separation between lithium and the remaining cobalt-containing metals.

[0054] The present invention preferably adopts two-stage calcination treatment, which can better occur the above reactions, improve the leaching rate of lithium, and achieve the separation between lithium and the remaining cobalt-containing metals.

[0055] Preferably, the leaching includes first water leaching and acid leaching carried out in sequence.

[0056] Preferably, in the first water leaching, the liquid-solid ratio of water to the calcined material is (1 - 20) mL:1 g. For example, it can be 1 mL:1 g, 4 mL:1 g, 6 mL:1 g, 8 mL:1 g, 10 mL:1 g, 12 mL:1 g, 14 mL:1 g, 16 mL:1 g, 18 mL:1 g or 20 mL:1 g, etc., but not limited to the listed values. Other unlisted values within this range are equally applicable.

[0057] Preferably, the temperature of the first water leaching is 15 - 30 °C. For example, it can be 15 °C, 17 °C, 19 °C, 20 °C, 22 °C, 24 °C, 25 °C, 27 °C, 29 °C or 30 °C, etc., but not limited to the listed values. Other unlisted values within this range are equally applicable. The time is 60 - 160 min. For example, it can be 60 min, 72 min, 85 min, 94 min, 105 min, 116 min, 127 min, 138 min, 149 min or 160 min, etc., but not limited to the listed values. Other unlisted values within this range are equally applicable.

[0058] Preferably, after the first water leaching, solid-liquid separation is carried out to obtain a lithium-containing solution and a water leaching residue.

[0059] Preferably, the acid leaching includes leaching the water leaching residue with an acid solution to obtain a nickel-cobalt-manganese-containing solution and silicon slag.

[0060] Preferably, the liquid-solid ratio of the acid solution to the water leaching residue in the acid leaching is (1-20) mL:1 g, for example, it can be 1 mL:1 g, 4 mL:1 g, 6 mL:1 g, 8 mL:1 g, 10 mL:1 g, 12 mL:1 g, 14 mL:1 g, 16 mL:1 g, 18 mL:1 g or 20 mL:1 g, etc., but not limited to the listed values, and other unlisted values within this range are equally applicable.

[0061] Preferably, the temperature of the acid leaching is 50-100 °C, for example, it can be 50 °C, 56 °C, 62 °C, 67 °C, 73 °C, 78 °C, 84 °C, 89 °C, 95 °C or 100 °C, etc., but not limited to the listed values, and other unlisted values within this range are equally applicable. The time is 60-160 min, for example, it can be 60 min, 72 min, 85 min, 94 min, 105 min, 116 min, 127 min, 138 min, 149 min or 160 min, etc., but not limited to the listed values, and other unlisted values within this range are equally applicable.

[0062] Preferably, the acid in the acid solution for the acid leaching is sulfuric acid.

[0063] Preferably, the acid concentration of the acid solution in the acid leaching is 0.8-2.8 mol / L, for example, it can be 0.8 mol / L, 1.1 mol / L, 1.3 mol / L, 1.5 mol / L, 1.7 mol / L, 2 mol / L, 2.2 mol / L, 2.4 mol / L, 2.6 mol / L or 2.8 mol / L, etc., but not limited to the listed values, and other unlisted values within this range are equally applicable.

[0064] Preferably, hydrogen peroxide is also added in the acid leaching.

[0065] Preferably, hydrogen peroxide is added in the acid leaching of the present invention, so as to better oxidize the valuable elements in the water leaching residue and improve the recovery rate and leaching rate of the valuable elements.

[0066] Preferably, the concentration of hydrogen peroxide in the acid leaching is 5-20 g / L, for example, it can be 5 g / L, 7 g / L, 9 g / L, 10 g / L, 12 g / L, 14 g / L, 15 g / L, 17 g / L, 19 g / L or 20 g / L, etc., but not limited to the listed values, and other unlisted values within this range are equally applicable.

[0067] Preferably, CuO is prepared using the copper powder and the silicon slag. xThe CuO / SiO2 catalyst comprises: the copper powder is successively dissolved in nitric acid and complexed with ammonia to obtain ammonia-complexed copper; the silicon slag is dissolved in an alkaline solution to obtain a silicon source solution; the ammonia-complexed copper and the silicon source solution are mixed and subjected to a coprecipitation reaction to obtain a solid-phase product; the solid-phase product is successively aged, washed, dried, ground and formed to obtain the CuO / SiO2 catalyst. x / SiO2 catalyst.

[0068] Preferably, the concentration of the nitric acid is 1-10 mol / L, for example, it can be 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, 6 mol / L, 7 mol / L, 8 mol / L, 9 mol / L or 10 mol / L, etc., but not limited to the listed values, and other unlisted values within this range are equally applicable.

[0069] The copper powder separated in the present invention can be used as copper nitrate. Copper nitrate is an important raw material for preparing Cu-Zn-Al series catalysts. Copper reacts with dilute nitric acid to produce copper nitrate; 3Cu + 8HNO3 (dilute) === 3Cu(NO3)2 + 2NO↑ + 4H2O. The copper nitrate prepared from the copper powder and silicon dioxide can prepare the catalyst CuO / SiO2, and this catalyst has advantages such as a high specific surface area, Cu loading, dispersibility and stability. x / SiO2, and this catalyst has advantages such as a high specific surface area, Cu loading, dispersibility and stability.

[0070] Preferably, the ammonia complexation includes: mixing the copper nitrate solution after dissolving the copper powder with ammonia water for ammonia complexation.

[0071] Preferably, the mass concentration of ammonia water in the ammonia complexation is 10-25%, for example, it can be 10%, 12%, 14%, 15%, 17%, 19%, 20%, 22%, 24% or 25%, etc., but not limited to the listed values, and other unlisted values within this range are equally applicable.

[0072] Preferably, the molar ratio of ammonia in the ammonia water to copper in the copper nitrate solution is (4-6):1, for example, it can be 4:1, 4.3:1, 4.5:1, 4.7:1, 4.9:1, 5.2:1, 5.4:1, 5.6:1, 5.8:1 or 6:1, etc., but not limited to the listed values, and other unlisted values within this range are equally applicable.

[0073] Preferably, the mass concentration of silicon in the silicon source solution is 20-40%, for example, it can be 20%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 32%, 35%, 38%, 39% or 40%, etc., but not limited to the listed values, and other unlisted values within this range are equally applicable.

[0074] Preferably, the molar ratio of silicon in the silicon source solution to copper in the ammonia-complexed copper is (1-6):1. For example, it can be 1:1, 1.2:1, 1.3:1, 1.5:1, 1.8:1, 2.0:1, 2.2:1, 2.5:1, 2.8:1, 3.0:1, 3.5:1, 4.0:1, 4.5:1, 5.0:1, 5.5:1 or 6.0:1, etc. However, it is not limited to the listed values, and other unlisted values within this range are equally applicable.

[0075] Preferably, the pH of the coprecipitation reaction is 9-11. For example, it can be 9, 9.3, 9.5, 9.7, 9.9, 10.2, 10.4, 10.6, 10.8 or 11, etc. However, it is not limited to the listed values, and other unlisted values within this range are equally applicable.

[0076] Preferably, the time of the coprecipitation reaction is 0.1-3 h. For example, it can be 0.1 h, 0.5 h, 0.8 h, 1.1 h, 1.4 h, 1.8 h, 2.1 h, 2.4 h, 2.7 h or 3 h, etc. However, it is not limited to the listed values, and other unlisted values within this range are equally applicable.

[0077] Preferably, the temperature of the coprecipitation reaction is 70-100 °C. For example, it can be 70 °C, 74 °C, 77 °C, 80 °C, 84 °C, 87 °C, 90 °C, 94 °C, 97 °C or 100 °C, etc. However, it is not limited to the listed values, and other unlisted values within this range are equally applicable.

[0078] Preferably, the temperature of the aging is 60-85 °C. For example, it can be 60 °C, 63 °C, 66 °C, 69 °C, 72 °C, 74 °C, 77 °C, 80 °C, 83 °C or 85 °C, etc. However, it is not limited to the listed values, and other unlisted values within this range are equally applicable.

[0079] Preferably, the time of the aging is 0.1-5 h. For example, it can be 0.1 h, 0.7 h, 1.2 h, 1.8 h, 2.3 h, 2.9 h, 3.4 h, 4 h, 4.5 h or 5 h, etc. However, it is not limited to the listed values, and other unlisted values within this range are equally applicable.

[0080] Preferably, the temperature of the drying is 50-130 °C. For example, it can be 50 °C, 59 °C, 68 °C, 77 °C, 86 °C, 95 °C, 104 °C, 113 °C, 122 °C or 130 °C, etc. However, it is not limited to the listed values, and other unlisted values within this range are equally applicable.

[0081] Preferably, the drying time is 1 to 6 h. For example, it can be 1 h, 1.6 h, 2.2 h, 2.7 h, 3.3 h, 3.8 h, 4.4 h, 4.9 h, 5.5 h or 6 h, etc., but not limited to the listed values. Other unlisted values within this range are equally applicable.

[0082] It should be noted that the chemical composition of spodumene is LiAl[Si2O6], and the theoretical content of Li2O in it is as high as 8.03%. The spodumene concentrate generally contains 6.3 - 7.5% of Li2O. For example, it can be 6.3%, 6.5%, 6.6%, 6.7%, 6.9%, 7%, 7.1%, 7.3%, 7.4% or 7.5%, etc., but not limited to the listed values. Other unlisted values within this range are equally applicable. It is an important lithium-containing resource.

[0083] The ternary power lithium-ion battery contains a large amount of valuable metals. Generally, the Co content in the ternary power lithium-ion battery is 5% - 20%. For example, it can be 5%, 7%, 9%, 10%, 12%, 14%, 15%, 17%, 19% or 20%, etc., but not limited to the listed values. Other unlisted values within this range are equally applicable; the Ni content is 5% - 12%. For example, it can be 5%, 5.8%, 6.6%, 7.4%, 8.2%, 8.9%, 9.7%, 10.5%, 11.3% or 12%, etc., but not limited to the listed values. Other unlisted values within this range are equally applicable; the Mn content is 7% - 10%. For example, it can be 7%, 7.4%, 7.7%, 8%, 8.4%, 8.7%, 9%, 9.4%, 9.7% or 10%, etc., but not limited to the listed values. Other unlisted values within this range are equally applicable; the Li content is 2% - 5%. For example, it can be 2%, 2.4%, 2.7%, 3%, 3.4%, 3.7%, 4%, 4.4%, 4.7% or 5%, etc., but not limited to the listed values. Other unlisted values within this range are equally applicable.

[0084] As a preferred technical solution of the present invention, a method for recycling waste lithium-ion batteries is provided. The method includes:

[0085] The battery negative electrode is successively subjected to disassembly, first crushing to 20 - 80 meshes and screening separation to obtain negative electrode carbon powder and copper powder.

[0086] The positive electrode of the battery is crushed to 60-80 mesh for the second time to obtain the positive electrode powder of the battery. According to the mass ratio of the positive electrode powder of the battery to the negative carbon powder being (2-3):1, the mass ratio of the positive electrode powder of the battery to spodumene being (2-3):1, and the mass ratio of anthracite to spodumene being (2-4):1, the positive electrode powder of the battery, the negative carbon powder, spodumene and anthracite are mixed to obtain a mixed material, and the mixed material is ball-milled at 90-180 r / min for 30-150 min to obtain a ball-milled mixed material; wherein, the abrasive for ball-milling is any one or a combination of at least two of brown fused alumina, white fused alumina or zirconium corundum; the mass ratio of the abrasive to the mixed material is (1-1.5):1.

[0087] According to the liquid-solid ratio of (1-2) mL:1 g, the ball-milled mixed material and a 2-8 mol / L sodium hydroxide solution are mixed, and ball-milling activation treatment is carried out at 60-180 r / min, 80-90 °C and a ball-to-material mass ratio of (1-2):1 for 90-120 min to obtain an activated material.

[0088] The activated material is first calcined at 900-1100 °C for 60-120 min, and then calcined at 1100-1350 °C but not including 1100 °C for 30-60 min to obtain a calcined material.

[0089] According to the liquid-solid ratio of (1-20) mL:1 g, water and the calcined material are mixed, leached at 15-30 °C for 60-160 min, and then solid-liquid separation is carried out to obtain a lithium-containing solution and a water leaching residue.

[0090] According to the liquid-solid ratio of (1-20) mL:1 g, sulfuric acid with a concentration of 0.8-2.8 mol / L and the water leaching residue are mixed, and 5-20 g / L hydrogen peroxide is added at the same time. Acid leaching is carried out at 50-100 °C for 60-160 min, and then solid-liquid separation is carried out to obtain a nickel-cobalt-manganese-containing solution and a silicon slag.

[0091] The copper powder is dissolved in 1-10 mol / L nitric acid to obtain a copper nitrate solution; according to the molar ratio of ammonia to copper in the copper nitrate solution being (4-6):1, the copper nitrate solution and ammonia water with a mass concentration of 10-25% are mixed for ammonia complexation to obtain ammonia complexed copper; the silicon slag is dissolved in an alkali solution to obtain a silicon source solution with a silicon mass concentration of 20%-40%; according to the molar ratio of silicon to copper being (1-6):1, the ammonia complexed copper and the silicon source solution are mixed, and a coprecipitation reaction is carried out at pH 9-11 and a temperature of 70-100 °C for 0.1-3 h to obtain a solid-phase product; the solid-phase product is successively aged at 60-85 °C for 0.1-5 h, washed, dried at 50-130 °C for 1-6 h, ground and formed to obtain the CuO x / SiO2 catalyst.

[0092] The present invention has no special restrictions on the solid-liquid separation in the above process, and any device and method for solid-liquid separation well-known to those skilled in the art can be adopted, and it can also be adjusted according to the actual process. For example, it can be filtration, centrifugation or sedimentation separation, etc., or a combination of different methods.

[0093] The present invention also has no special restrictions on the drying in the above process, and any device and method for drying well-known to those skilled in the art can be adopted, and it can also be adjusted according to the actual process. For example, it can be air drying, vacuum drying, baking or freeze drying, etc., or a combination of different methods.

[0094] The present invention has no special restrictions on the crushing in the above process, and any device and method for crushing well-known to those skilled in the art can be adopted, and it can also be adjusted according to the actual process. For example, it can be grinding, extrusion crushing, splitting crushing or impact crushing, etc., or a combination of different methods.

[0095] Compared with the prior art, the present invention has at least the following beneficial effects:

[0096] (1) The method for recycling waste lithium-ion batteries provided by the present invention enables the combined recovery of spodumene and the positive and negative electrodes of waste lithium-ion batteries, jointly processes the lithium-containing material spodumene with the positive and negative electrodes of waste lithium-ion batteries, realizes the preparation of valuable metals Ni, Co, Mn and Li, and achieves the full recovery treatment of each component. Among them, under the preferred conditions, the recovery rate of lithium is above 90.63%, the recovery rate of cobalt is above 92.63%, the recovery rate of manganese is above 93.94%, the recovery rate of nickel is above 92.11%, the recovery rate of copper is above 89.79%, and the recovery rate of silicon is above 92.26%.

[0097] (2) In the method for recycling waste lithium-ion batteries provided by the present invention, considering that the recovery value of Al in the waste battery positive electrode and the negative electrode carbon powder is low, they can be directly not separated and used as reducing agents; making full use of the activity and reducibility of Al in the positive electrode sheet, spodumene will fully react with the aluminum powder on the battery positive electrode powder under high-temperature conditions, realizing the resource utilization of waste aluminum foil.

[0098] (3) The method for recycling waste lithium-ion batteries provided by the present invention uses anthracite to supplement the carbon source. Anthracite has the highest content, the best reduction performance and less impurity content. Anthracite is fully mixed and evenly distributed with the waste battery positive electrode powder, and carbon thermal reduction of the battery is carried out during the calcination process, which can strengthen the reduction effect. Description of the Drawings

[0099] Figure 1 It is a flow chart of the method for recycling waste lithium-ion batteries provided in Embodiment 1 of the present invention. Detailed Embodiments

[0100] To facilitate the understanding of the present invention, the following embodiments are enumerated. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0101] It should be understood that the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise stated, the meaning of "a plurality" is two or more.

[0102] Embodiment 1

[0103] This embodiment provides a method for recycling waste lithium-ion batteries. Refer to Figure 1 , the method includes the following steps:

[0104] The negative electrode of the lithium cobalt oxide battery is successively subjected to shearing and crushing until it is crushed to 20 - 40 mesh, and then sieved to obtain the first negative electrode carbon powder and the first mixed oversize material (containing carbon powder and copper powder). The first mixed oversize material is subjected to first crushing to 20 - 40 mesh and screening separation to obtain the second negative electrode carbon powder and copper powder. The first negative electrode carbon powder and the second negative electrode carbon powder are mixed as the negative electrode carbon powder. The battery positive electrode (the positive electrode of the lithium cobalt oxide battery and the positive electrode of the ternary lithium-ion battery) is subjected to second crushing to 60 - 80 mesh to obtain the battery positive electrode powder. According to the mass ratio of the battery positive electrode powder to the negative electrode carbon powder being 2:1, and the mass ratio of anthracite, the battery positive electrode powder and spodumene (with a Li2O content of 6.3%) being 3:2.8:1, the mixed battery positive electrode powder, negative electrode carbon powder, spodumene and anthracite are mixed to obtain a mixed material, and the mixed material is ball-milled at 100 r / min for 30 min to obtain a ball-milled mixed material; wherein, the abrasive for ball-milling is white corundum; the mass ratio of the abrasive to the mixed material is 1:1.

[0105] According to the liquid-solid ratio of 1.5 mL:1 g, the ball-milled mixed material and a 2 mol / L sodium hydroxide solution are mixed, and ball-milling activation treatment is carried out at 60 r / min, a temperature of 80 °C, and a ball-to-material mass ratio of 1.5:1 for 100 min to obtain an activated material.

[0106] The activated material is successively subjected to first calcination at 900 °C for 90 min and second calcination at 1100 °C for 60 min to obtain a calcined material.

[0107] According to the liquid-solid ratio of 10 mL:1 g, water and the calcined material are mixed, and leaching is carried out at 20 °C for 160 min (i.e., water leaching), and then filtration is carried out to obtain a lithium-containing solution and a water leaching residue. The lithium-containing solution can be used for the preparation of battery-grade lithium salts.

[0108] According to a liquid-solid ratio of 8 mL:1 g, a sulfuric acid solution with a concentration of 1.5 mol / L and water-leached residue are mixed, and 10 g / L hydrogen peroxide (the final concentration of hydrogen peroxide is 10 g / L) is added simultaneously. Acid leaching is carried out at 50 °C for 80 min, and after filtration, a nickel-cobalt-manganese-containing solution and silicon slag are obtained. The nickel-cobalt-manganese-containing solution can be used for the preparation of battery-grade cobalt sulfate solution / crystals.

[0109] The copper powder is dissolved in 5 mol / L nitric acid to obtain a copper nitrate solution; according to a molar ratio of ammonia to copper in the copper nitrate solution of 4:1, the copper nitrate solution and ammonia water with a mass concentration of 14% are mixed for ammonia complexation to obtain ammonia-complexed copper; the silicon slag is dissolved in a sodium hydroxide solution with a mass concentration of 30% to obtain a silicon source solution with a silicon mass concentration of 25%; according to a molar ratio of silicon to copper of 3:1, the ammonia-complexed copper and the silicon source solution are mixed, and a coprecipitation reaction is carried out at pH 10 and a temperature of 80 °C for 0.2 h to obtain a solid-phase product; the solid-phase product is successively aged at 75 °C for 1 h, centrifugally washed, dried at 60 °C for 3 h, ground, and formed to obtain CuO x / SiO2 catalyst.

[0110] Example 2

[0111] This example provides a method for recycling waste lithium-ion batteries, and the method includes the following steps:

[0112] The negative electrode of the lithium cobalt oxide battery is successively sheared and crushed to 20 - 40 mesh, and then screened to obtain the first negative electrode carbon powder and the first mixed oversize material (containing carbon powder and copper powder). The first mixed oversize material is first crushed to 40 - 60 mesh and screened and sorted to obtain the second negative electrode carbon powder and copper powder. The first negative electrode carbon powder and the second negative electrode carbon powder are mixed as the negative electrode carbon powder. The battery positive electrode (the positive electrode of the lithium cobalt oxide battery and the positive electrode of the ternary lithium-ion battery) is secondarily crushed to 60 - 80 mesh to obtain battery positive electrode powder. According to a mass ratio of battery positive electrode powder to negative electrode carbon powder of 2.2:1 and a mass ratio of anthracite, battery positive electrode powder, and spodumene (Li2O content is 6.4%) of 2.5:2.5:1, the battery positive electrode powder, negative electrode carbon powder, spodumene, and anthracite are mixed to obtain a mixed material, and the mixed material is ball-milled at 180 r / min for 60 min to obtain a ball-milled mixed material; among them, the abrasive for ball milling is white corundum; the mass ratio of the abrasive to the mixed material is 1.2:1.

[0113] According to a liquid-solid ratio of 1.01 mL / g, the ball-milled mixed material and 4 mol / L sodium hydroxide solution are mixed, and ball-milling activation treatment is carried out at 90 r / min, a temperature of 85 °C, and a ball-to-material mass ratio of 1:1 for 90 min to obtain an activated material.

[0114] The activated material is calcined at 1000°C for 70 minutes and then at 1200°C for 45 minutes in sequence to obtain the calcined material.

[0115] According to the liquid-solid ratio of 12 mL:1 g, water and the calcined material are mixed, leached at 25°C for 80 minutes, and then filtered to obtain a lithium-containing solution and a water leaching residue. The lithium-containing solution can be used for the preparation of battery-grade lithium salts.

[0116] According to the liquid-solid ratio of 10 mL:1 g, a sulfuric acid solution with a concentration of 2 mol / L and the water leaching residue are mixed, and 10 g / L hydrogen peroxide (the final concentration of hydrogen peroxide is 10 g / L) is added simultaneously. Leaching is carried out at 70°C for 90 minutes, and then filtered to obtain a nickel-cobalt-manganese-containing solution and a silicon residue. The nickel-cobalt-manganese-containing solution can be used for the preparation of battery-grade cobalt sulfate solution / crystals.

[0117] The copper powder is dissolved in 4 mol / L nitric acid to obtain a copper nitrate solution; according to the molar ratio of ammonia to copper in the copper nitrate solution of 4.5:1, the copper nitrate solution and ammonia water with a mass concentration of 10% are mixed for ammonia complexation to obtain ammonia-complexed copper; the silicon residue is dissolved in a sodium hydroxide solution with a mass concentration of 30% to obtain a silicon source solution with a silicon mass concentration of 40%; according to the molar ratio of silicon to copper of 4:1, the ammonia-complexed copper and the silicon source solution are mixed, and a coprecipitation reaction is carried out at pH 11 and a temperature of 80°C for 2 hours to obtain a solid-phase product; the solid-phase product is aged at 70°C for 3.5 hours, centrifuged and washed, dried at 120°C for 1.5 hours, ground and formed to obtain CuO x / SiO2 catalyst.

[0118] Example 3

[0119] This example provides a method for recycling waste lithium-ion batteries, and the method includes the following steps:

[0120] The negative electrode of the lithium cobalt oxide battery is sequentially sheared and crushed to 20-40 mesh, and then screened to obtain the first negative electrode carbon powder and the first mixed oversize material (containing carbon powder and copper powder). The first mixed oversize material is crushed to 40-60 mesh for the first time and screened and sorted to obtain the second negative electrode carbon powder and copper powder. The first negative electrode carbon powder and the second negative electrode carbon powder are mixed as the negative electrode carbon powder. The battery positive electrode (the positive electrode of the lithium cobalt oxide battery and the positive electrode of the ternary lithium-ion battery) is crushed to 60-80 mesh for the second time to obtain the battery positive electrode powder. According to the mass ratio of the battery positive electrode powder to the negative electrode carbon powder of 2.5:1, and the mass ratio of anthracite, the battery positive electrode powder and spodumene (Li2O content is 6.7%) of 2:2:1, the battery positive electrode powder, the negative electrode carbon powder, spodumene and anthracite are mixed to obtain a mixed material, and the mixed material is ball-milled at 120 r / min for 50 minutes to obtain a ball-milled mixed material; among them, the abrasive for ball milling is zircon corundum; the mass ratio of the abrasive to the mixed material is 1.4:1.

[0121] Mix the mixed ball-milled material and 8 mol / L sodium hydroxide solution according to a liquid-solid ratio of 2 mL:1 g, and perform ball-milling activation treatment for 100 min at 180 r / min, a temperature of 85 °C, and a ball-to-material mass ratio of 1.5:1 to obtain the activated material.

[0122] The activated material is calcined at 1100 °C for 120 min and then calcined at 1150 °C for 60 min in sequence to obtain the calcined material.

[0123] Mix water and the calcined material according to a liquid-solid ratio of 20 mL:1 g, leach at 30 °C for 60 min, and then filter to obtain a lithium-containing solution and a water leaching residue. The lithium-containing solution can be used for the preparation of battery-grade lithium salts.

[0124] Mix a sulfuric acid solution with a concentration of 0.8 mol / L and the water leaching residue according to a liquid-solid ratio of 20 mL:1 g, and simultaneously add 20 g / L hydrogen peroxide (the final concentration of hydrogen peroxide is 20 g / L). Acid leach at 100 °C for 90 min, and then filter to obtain a nickel-cobalt-manganese-containing solution and a silicon residue. The nickel-cobalt-manganese-containing solution can be used for the preparation of battery-grade cobalt sulfate solution / crystals.

[0125] The copper powder is dissolved in 1 mol / L nitric acid to obtain a copper nitrate solution; according to a molar ratio of ammonia to copper in the copper nitrate solution of 6:1, mix the copper nitrate solution and 22% by mass ammonia water for ammonia complexation to obtain ammonia-complexed copper; the silicon residue is dissolved in a 25% by mass sodium hydroxide solution to obtain a silicon source solution with a silicon mass concentration of 20%; according to a molar ratio of silicon to copper of 6:1, mix the ammonia-complexed copper and the silicon source solution, and carry out a coprecipitation reaction at pH 9 and a temperature of 100 °C for 3 h to obtain a solid-phase product; the solid-phase product is aged at 85 °C for 0.1 h, centrifuged and washed, dried at 130 °C for 1 h, ground and formed to obtain CuO x / SiO2 catalyst.

[0126] Example 4

[0127] This example provides a method for recycling waste lithium-ion batteries, and the method includes the following steps:

[0128] The negative electrode of the lithium cobalt oxide battery is successively subjected to shearing and crushing, crushed to 20-40 mesh, and then screened to obtain the first negative electrode carbon powder and the first mixed oversize material (containing carbon powder and copper powder). The first mixed oversize material is subjected to first crushing to 40-60 mesh and screening and separation to obtain the second negative electrode carbon powder and copper powder. The first negative electrode carbon powder and the second negative electrode carbon powder are mixed as the negative electrode carbon powder. The battery positive electrode (the lithium cobalt oxide battery positive electrode and the ternary lithium ion battery positive electrode) is subjected to second crushing to 60-80 mesh to obtain the battery positive electrode powder. According to the mass ratio of the battery positive electrode powder to the negative electrode carbon powder being 3:1, and the mass ratio of anthracite, the battery positive electrode powder and spodumene (Li2O content is 7.2%) being 4:3:1, the mixed battery positive electrode powder, negative electrode carbon powder, spodumene and anthracite are mixed to obtain a mixed material, and the mixed material is ball-milled at 180 r / min for 30 min to obtain a ball-milled mixed material; wherein, the abrasive for ball milling is brown fused alumina; the mass ratio of the abrasive to the mixed material is 1.5:1.

[0129] According to the liquid-solid ratio of 1 mL:1 g, the ball-milled mixed material and a 2 mol / L sodium hydroxide solution are mixed, and ball-milling activation treatment is carried out at 120 r / min, a temperature of 90 °C, and a ball-to-material mass ratio of 2:1 for 120 min to obtain an activated material.

[0130] The activated material is successively subjected to first calcination at 900 °C for 120 min and second calcination at 1350 °C for 30 min to obtain a calcined material.

[0131] According to the liquid-solid ratio of 1 mL:1 g, water and the calcined material are mixed, leached at 25 °C for 140 min, and filtered to obtain a lithium-containing solution and a water leaching residue. The lithium-containing solution can be used for the preparation of battery-grade lithium salts.

[0132] According to the liquid-solid ratio of 1 mL:1 g, a sulfuric acid solution with a concentration of 2.8 mol / L and the water leaching residue are mixed, and 5 g / L hydrogen peroxide (the final concentration of hydrogen peroxide is 5 g / L) is added at the same time. Acid leaching is carried out at 65 °C for 160 min, and filtered to obtain a nickel-cobalt-manganese-containing solution and silicon slag. The nickel-cobalt-manganese-containing solution can be used for the preparation of battery-grade cobalt sulfate solution / crystals.

[0133] The copper powder is dissolved in 10 mol / L nitric acid to obtain a copper nitrate solution; according to the molar ratio of ammonia to copper in the copper nitrate solution being 5.5:1, the copper nitrate solution and 25% by mass ammonia water are mixed for ammonia complexation to obtain ammonia-complexed copper; the silicon slag is dissolved in a 35% by mass sodium hydroxide solution to obtain a silicon source solution with a silicon mass concentration of 27%; according to the molar ratio of silicon to copper being 1:1, the ammonia-complexed copper and the silicon source solution are mixed, and a coprecipitation reaction is carried out at pH 10.5 and a temperature of 70 °C for 0.1 h to obtain a solid-phase product; the solid-phase product is successively subjected to aging at 60 °C for 5 h, centrifugal washing, drying at 50 °C for 6 h, grinding and shaping to obtain CuO x / SiO2 catalyst.

[0134] Example 5

[0135] This example provides a method for recycling waste lithium-ion batteries. Except that sodium hydroxide solution is not added during the ball milling activation treatment, the rest are the same as in Example 1 and will not be elaborated here.

[0136] Example 6

[0137] This example provides a method for recycling waste lithium-ion batteries. Except that the first calcination is not carried out and the duration of the second calcination is extended to 150 min, the rest are the same as in Example 1 and will not be elaborated here.

[0138] Example 7

[0139] This example provides a method for recycling waste lithium-ion batteries. Except that the second calcination is not carried out and the duration of the first calcination is extended to 150 min, the rest are the same as in Example 1 and will not be elaborated here.

[0140] Example 8

[0141] This example provides a method for recycling waste lithium-ion batteries. Except that hydrogen peroxide is not added during the sulfuric acid solution leaching, the rest are the same as in Example 1 and will not be elaborated here.

[0142] Example 9

[0143] This example provides a method for recycling waste lithium-ion batteries. Except that the addition amount of anthracite is relatively low, specifically, the mass ratio of anthracite to spodumene is 1.0:1, the rest are the same as in Example 1 and will not be elaborated here.

[0144] Example 10

[0145] This example provides a method for recycling waste lithium-ion batteries. Except that the addition amount of anthracite is relatively high, specifically, the mass ratio of anthracite to spodumene is 5.0:1, the rest are the same as in Example 1 and will not be elaborated here.

[0146] Example 11

[0147] This example provides a method for recycling waste lithium-ion batteries. Except that the addition amount of spodumene is relatively low, specifically, the mass ratio of battery cathode powder to spodumene is 4:1, the rest are the same as in Example 1 and will not be elaborated here.

[0148] Example 12

[0149] This embodiment provides a method for recycling waste lithium-ion batteries. Except that the addition amount of spodumene is on the high side, specifically, the mass ratio of the battery positive electrode powder to spodumene is 1:1, the rest are the same as those in Embodiment 1 and will not be elaborated here.

[0150] Embodiment 13

[0151] This embodiment provides a method for recycling waste lithium-ion batteries. Except that anthracite is replaced by lignite, the rest are the same as those in Embodiment 1 and will not be elaborated here.

[0152] Comparative Example 1

[0153] This comparative example provides a method for recycling waste lithium-ion batteries. Except that spodumene is not added, the rest are the same as those in Embodiment 1 and will not be elaborated here.

[0154] Comparative Example 2

[0155] This comparative example provides a method for recycling waste lithium-ion batteries. Except that anthracite is not added, the rest are the same as those in Embodiment 1 and will not be elaborated here.

[0156] Comparative Example 3

[0157] This comparative example provides a method for recycling waste lithium-ion batteries. Except that ball milling activation treatment is not carried out, the rest are the same as those in Embodiment 1 and will not be elaborated here.

[0158] Comparative Example 4

[0159] This comparative example provides a method for recycling waste lithium-ion batteries. Except that negative electrode carbon powder is not mixed, and only battery positive electrode powder, spodumene and anthracite are mixed, the rest are the same as those in Embodiment 1 and will not be elaborated here.

[0160] Testing method: The main component of the spodumene used in the above embodiments and comparative examples is LiAl[Si2O6], and the recyclable elements are Li, Al and Si. The battery negative electrode contains copper and carbon, and the recyclable element is Cu. The battery positive electrode is mainly the positive electrode of lithium cobalt oxide battery, and ternary lithium-ion battery positive electrode will be doped in actual production, and the recyclable elements are Li, Co, Mn and Ni. ICP detection is used to calculate and evaluate the recovery rates of lithium, cobalt, manganese, copper, silicon and nickel; XRD is used to test the Cu loading amount in the CuO x / SiO2 catalyst, and the BET surface testing method is used to test the specific surface area of the CuO x / SiO2 catalyst.

[0161] The test results of the above embodiments and comparative examples are shown in Table 1.

[0162] Table 1

[0163]

[0164] In Table 1, " / " indicates that there is no relevant test data.

[0165] It can be seen from Table 1 as follows:

[0166] (1) From comprehensive Examples 1 to 4, it can be seen that the method for jointly recovering the positive and negative electrodes of spodumene mixed with waste lithium-ion batteries provided by the present invention has a high recovery rate for each element. Among them, the recovery rate of lithium is above 90.63%, the recovery rate of cobalt is above 92.63%, the recovery rate of manganese is above 93.94%, the recovery rate of nickel is above 92.11%, the recovery rate of copper is above 89.79%, and the recovery rate of silicon is above 92.26%. Moreover, the finally prepared CuO x / SiO2 catalyst has a high Cu loading amount, above 9.45%. The CuO x / SiO2 catalyst has a specific surface area above 93 cm 2 / mg and has excellent catalytic performance.

[0167] (2) From comprehensive Examples 1 and 5 to 7, it can be seen that in Example 5, no sodium hydroxide solution is added during the ball milling activation treatment, resulting in a decrease in the lithium recovery rate to 64.23%, and the recovery rates of manganese and silicon both decrease. This is because the aluminum oxide film on the surface of the Al foil remains in Example 5, and the reaction effect of spodumene in the first calcination process is relatively poor, the water leaching Li leaching rate is low, and Li cannot achieve the preferred lithium extraction effect when entering the acid leaching link; in Example 6, the first calcination is not carried out, and the duration of the second calcination is extended to 150 min, resulting in an extension of the carbothermal reduction time, an increase in the reduction degree and crystallinity of the waste battery cathode material, and both nickel and cobalt are reduced to elemental forms. At this time, the leaching of lithium is relatively easy, but with the extension of time, a small amount of lithium (Li2CO3) will volatilize, and the longer high-temperature reaction time results in a decrease in the lithium leaching rate; in Example 7, the reaction is only carried out under the first calcination condition, the temperature is relatively low, the reduction degree of the battery material is relatively low, and the binder and electrolyte are not dissociated completely enough, resulting in difficult lithium leaching; thus, it shows that the present invention preferably combines ball milling activation treatment with staged calcination, which can significantly improve the lithium leaching rate.

[0168] (3) It can be seen from a comprehensive comparison of Example 1 and Example 8 that in Example 1, hydrogen peroxide was added during acid leaching. Compared with Example 8 where no hydrogen peroxide was added, the recovery rates of all elements in Example 1 were above 90%, while the recovery rate of nickel in Example 8 was only 7.66%. This is because the main components of the water leaching residue are oxides and elemental substances. Without adding hydrogen peroxide, low-valent metals and elemental metals cannot be completely leached, resulting in a decrease in the leaching rates of Ni, Co, and Mn. Thus, it is shown that the present invention preferably adds hydrogen peroxide during acid leaching, which can simultaneously achieve the leaching and recovery of other valuable elements.

[0169] (4) It can be seen from a comprehensive comparison of Example 1 and Examples 9 - 10 that in Example 9, the mass ratio of anthracite to spodumene was 1.0:1, with insufficient carbon source, resulting in a lower degree of reduction of the cathode material and a low leaching rate of lithium. In Example 10, the mass ratio of anthracite to spodumene was 5.0:1, with an excessive amount of carbon source added, resulting in an increase in the content of insoluble substances in the acid leaching residue, an increase in the gas production during the pyrometallurgical reaction process, and a decrease in the recovery rate of nickel. Thus, it is shown that the present invention preferably controls the mass ratio of anthracite to spodumene within a reasonable range, which can better improve the recovery rate of lithium and optimize the production process.

[0170] Similarly, it can be seen from a comparison of Example 1 and Examples 11 - 12 that the recovery rate of lithium in Example 1 was 94.68%. In Example 11, the mass ratio of the battery cathode powder to spodumene was 4:1, resulting in poor reaction effect of spodumene during the first-stage calcination process and a low leaching rate of lithium in water leaching. In Example 12, the mass ratio of the battery cathode powder to spodumene was 1:1, resulting in low application efficiency of the Al foil, with some Al foil transformed into pure impurities and not being effectively recycled. Thus, it is shown that the present invention preferably controls the mass ratio of the battery cathode powder to spodumene within a reasonable range, which can further improve the recovery rates of all elements.

[0171] (5) It can be seen from a comprehensive comparison of Example 1 and Example 13 that when anthracite was replaced with lignite in Example 13, it led to a high organic matter content and many residual impurities, affecting the acid leaching and filtration effects of the water leaching residue and resulting in a decrease in the recovery rate of manganese.

[0172] (6) In Comparative Example 1, spodumene was not added, resulting in the high-temperature oxidation of the Al foil to Al2O3, which was transformed into pure impurities and not effectively recycled. In Comparative Example 2, the carbon source was insufficient, the reduction degree of the cathode material was low, and the lithium leaching rate was low. In Comparative Example 3, no ball milling activation treatment was carried out, resulting in a low reaction rate, large material consumption, low reaction activity, and insufficient reduction during the subsequent first calcination process, and the recovery rates of lithium and other elements decreased. In Comparative Example 4, no negative electrode carbon powder was mixed, resulting in an insufficient carbon source, a low reduction degree of the cathode material, and a low lithium leaching rate. It can be seen that the present invention realizes the full recovery of each element with high resource utilization efficiency and broad application prospects by adopting a method of jointly recovering the positive and negative electrodes to jointly treat spodumene containing lithium and the positive and negative electrodes of waste lithium-ion batteries.

[0173] The present invention illustrates the detailed features of the present invention through the above embodiments, but the present invention is not limited to the above detailed features, that is, it does not mean that the present invention must rely on the above detailed features to be implemented. Those skilled in the art should understand that any improvement of the present invention, the equivalent replacement of the technical features selected by the present invention, the addition of auxiliary technical features, and the selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for recycling waste lithium-ion batteries, characterized in that: The method comprises: The battery negative electrode is separated by copper to obtain negative electrode carbon powder and copper powder; Mixing battery positive electrode powder, negative electrode carbon powder, spodumene and a carbon source to obtain a mixture, and ball-milling the mixture to obtain a ball-milled mixture; The ball-milled mixture is activated, calcined and leached in sequence, and the leaching obtains a lithium-containing solution, a nickel-cobalt-manganese-containing solution and silicon slag; Preparation of CuO using the copper powder and the silicon slag x / SiO2 catalyst.

2. The method according to claim 1, characterized in that The mass ratio of the battery positive electrode powder and the negative electrode carbon powder is (2-3):1; Preferably, the mass ratio of the battery positive electrode powder to spodumene is (2-3):

1.

3. The method according to claim 1 or 2, characterized in that: The mass ratio of the carbon source to spodumene is (2-4):1; Preferably, the carbon source is anthracite.

4. The method according to any one of claims 1 to 3, characterized in that: The rotation speed of the ball mill is 90-180 r / min; Preferably, the ball milling time is 30 to 150 minutes; Preferably, the mass ratio of the abrasive to the mixed material in the ball mill is (1-1.5):1; Preferably, the abrasive for ball milling includes any one of brown corundum, white corundum or zirconium corundum, or a combination of at least two of them.

5. The method according to any one of claims 1 to 4, characterized in that: The activation comprises: mixing the ball milling mixture and the activator, and performing ball milling activation treatment.

6. The method according to claim 5, characterized in that The activator comprises an alkali solution, preferably a sodium hydroxide solution; Preferably, the alkali concentration of the alkali solution is 2 to 8 mol / L; Preferably, the temperature of the ball milling activation treatment is 80-90°C; Preferably, the liquid-to-solid ratio of the activator and the ball-milled mixture is (1-2) mL:1 g; Preferably, the mass ratio of the ball to material in the ball milling activation treatment is (1-2):1; Preferably, the rotation speed of the ball milling activation treatment is 60 to 180 r / min; Preferably, the ball milling activation treatment time is 90 to 120 minutes.

7. The method according to any one of claims 1 to 6, characterized in that: The calcination includes two stages of calcination, namely a first calcination and a second calcination; Preferably, the temperature of the first calcination is 900-1100°C and the time is 60-120 min; Preferably, the second calcination temperature is 1100-1350° C. but not including 1100° C., and the time is 30-60 min.

8. The method according to any one of claims 1 to 7, characterized in that: The leaching comprises a first water leaching and an acid leaching performed sequentially; Preferably, the liquid-to-solid ratio of water to the calcined material in the first water soak is (1-20) mL:1 g; Preferably, the temperature of the first water immersion is 15-30°C and the time is 60-160 minutes; Preferably, after the first water leaching, solid-liquid separation is performed to obtain a lithium-containing solution and water leaching residue; Preferably, the acid leaching comprises leaching the water leaching residue with an acid solution to obtain a nickel-cobalt-manganese-containing solution and silicon slag; Preferably, the liquid-to-solid ratio of the acid solution to the water-leached residue in the acid leaching is (1-20) mL:1 g; Preferably, the acid leaching temperature is 50-100°C and the time is 60-160min; Preferably, the acid in the acid solution in the acid leaching is sulfuric acid; Preferably, the acid concentration of the acid solution in the acid leaching is 0.8 to 2.8 mol / L; Preferably, hydrogen peroxide is also added during the acid leaching; Preferably, the concentration of hydrogen peroxide in the acid leaching is 5 to 20 g / L.

9. The method according to any one of claims 1 to 8, characterized in that: Preparation of CuO using the copper powder and the silicon slag x / SiO2 catalysts include: The copper powder is dissolved in nitric acid and complexed with ammonia in sequence to obtain ammonia-complexed copper; the silicon slag is dissolved in alkaline solution to obtain a silicon source solution; The ammonia complex copper and silicon source solution are mixed and subjected to a coprecipitation reaction to obtain a solid phase product; the solid phase product is sequentially aged, washed, dried, ground and formed to obtain the CuO x / SiO2 catalyst.

10. The method according to claim 9, characterized in that The concentration of the nitric acid is 1 to 10 mol / L; Preferably, the pH of the coprecipitation reaction is 9 to 11; Preferably, the coprecipitation reaction time is 0.1 to 3 hours; Preferably, the coprecipitation reaction temperature is 70-100°C; Preferably, the aging temperature is 60-85°C; Preferably, the aging time is 0.1 to 5 hours; Preferably, the drying temperature is 50-130°C; Preferably, the drying time is 1 to 6 hours.

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