A method for inhibiting the leaching of aluminum elements in ternary lithium battery waste

Abstract

The present invention provides a method for inhibiting the leaching of aluminum elements in ternary lithium battery waste. The valuable metal elements in the ternary lithium battery waste are reduced by a reduction roasting method, and then cooled. The whole process is carried out under argon protection, and then a leaching agent is added to selectively leach the valuable metal elements in the waste. The leaching agent is composed of a citric acid solution and thiourea. After filtering, a leaching solution containing lithium, nickel, cobalt, and manganese and a leaching residue containing a negative electrode graphite material and a current collector aluminum foil are obtained. The present invention controls the physical phase of the ternary lithium battery waste by controlling the reduction temperature, so that the high-valent metal elements are reduced to a low-valent state that is easy to leach, and a certain aluminum corrosion inhibitor thiourea is added to the leaching agent to inhibit the leaching of the aluminum element, so as to achieve the purpose of selectively leaching the valuable metal elements in the ternary lithium battery waste.

Description

Technical Field

[0001] The invention belongs to the technical field of recycling useful parts of waste batteries, and in particular relates to a method for inhibiting the leaching of aluminum elements in ternary lithium battery waste. Background Art

[0002] The positive electrode materials of ternary lithium batteries contain a large amount of metal elements with high recycling value, such as lithium, nickel, cobalt, and manganese. The waste materials are composed of failed positive electrode materials, negative electrode graphite and current collectors. With the popularization of new energy power, the number of waste ternary lithium batteries has also increased significantly. The traditional reduction roasting-acid leaching recovery process not only produces a large amount of inorganic waste acid that is difficult to handle during the recovery process, but also contains aluminum elements that make up the current collector (aluminum foil) in the leachate, and the complex metal ion (containing aluminum elements) solution causes difficulties for subsequent applications. Therefore, the development of selective leaching of valuable metal elements in ternary lithium battery waste has become a hot research topic in the field of waste battery recycling technology. Summary of the invention

[0003] In order to solve the problems existing in the prior art, the present invention provides a method for inhibiting the leaching of aluminum elements in ternary lithium battery waste. Compared with the traditional reduction roasting-acid leaching recovery process, the method can efficiently inhibit the leaching of aluminum elements in ternary lithium battery waste, and the leaching system is an environmentally friendly organic acid-citric acid and an organic corrosion inhibitor thiourea, which reduces the cost of waste liquid treatment. The method of the present invention has good engineering application value, economic value and environmental value.

[0004] The invention provides a method for inhibiting the leaching of aluminum elements in ternary lithium battery waste. The method comprises the following steps: reducing and roasting the valuable metal elements in the ternary lithium battery waste, cooling the waste, and performing the whole process under argon protection. Subsequently, a leaching agent is added to selectively leach the valuable metal elements in the waste. The leaching agent is composed of a citric acid solution and thiourea. After filtering, a leaching solution containing lithium, nickel, cobalt and manganese and a leaching residue containing a negative electrode graphite material and a current collector aluminum foil are obtained.

[0005] As a preferred embodiment, the ternary lithium battery waste is a mixture of ternary lithium battery positive and negative electrode materials and aluminum foil, and / or

[0006] The ternary lithium battery waste is in powder form.

[0007] As a preferred solution, the reduction roasting is carried out in a vacuum tube rotary furnace or a muffle furnace after evacuation.

[0008] As a preferred embodiment, the calcination temperature during the reduction calcination is 500-550°C, preferably 520°C-540°C; and / or

[0009] The reduction roasting time is 2.5-3h.

[0010] As a preferred solution, the gas flow rate during the reduction roasting and cooling is 0.5L-1L / min.

[0011] As a preferred embodiment, the concentration of the citric acid solution is 2.5-3 mol / L.

[0012] As a preferred embodiment, the liquid-to-solid ratio of the citric acid solution to the ternary lithium battery waste is 15-20 mL / g.

[0013] As a preferred solution, the addition amount of the aluminum corrosion inhibitor thiourea is 0.1%-0.3% of the total mass of the ternary lithium battery waste and the citric acid solution.

[0014] As a preferred solution, when the leaching agent is added for leaching, the leaching time is 2.5-3 hours.

[0015] As a preferred solution, the leaching rate of aluminum in the leaching solution is lower than 1%.

[0016] The beneficial effects of the present invention are as follows:

[0017] 1. The roasting process of the present invention is reduction roasting. Argon is introduced during the roasting process to avoid re-oxidation of high-valent metal elements reduced at high temperature. In addition, the roasting temperature is 500-550°C and the roasting time is 2.5-3h. If the roasting temperature is too low, the reduction rate of high-valent metal oxides in the waste is low and it is difficult to leach in citric acid. If the roasting temperature is too high, the content of metal elements in the waste is too high, and the reaction rate of nickel and cobalt elements with citric acid is lower than that of their oxides, resulting in a decrease in the leaching rate of valuable metals. At the same time, a certain amount of thiourea corrosion inhibitor is added to the leaching agent, which has a certain corrosion inhibition effect on metal elements, and also causes a decrease in the leaching rate of valuable metals. In addition, the aluminum foil material in the waste has a more violent reduction reaction and generates more carbon dioxide. The lithium element in the waste is easy to react with carbon dioxide to generate lithium carbonate, and lithium carbonate and aluminum foil form lithium aluminate. Since the acidity of the citric acid solution is not as strong as that of inorganic acids such as hydrochloric acid and sulfuric acid, the generated lithium aluminate has poor water solubility and reacts slowly with citric acid. This causes a large amount of lithium to remain in the leaching residue in the form of lithium aluminate, reducing the leaching rate of lithium.

[0018] 2. The present invention adds aluminum corrosion inhibitor thiourea to the leaching agent to form chemical adsorption on the surface of aluminum foil, thereby inhibiting the leaching of aluminum elements and achieving the purpose of selectively leaching valuable metal elements in ternary lithium battery waste.

[0019] 3. Compared with the traditional reduction roasting-inorganic strong acid leaching, the aluminum content in the obtained leachate is significantly reduced in the present invention, which is beneficial to the subsequent purification and separation. In addition, the leaching agent is an organic acid citric acid, which is more environmentally friendly and safer than inorganic strong acid as a leaching agent. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0021] Figure 1 This is the SEM-EDS image of the leached slag phase of the ternary lithium battery waste in Example 1.

[0022] Figure 2 This is the SEM-EDS image of the leached slag phase of the ternary lithium battery waste in comparative example 1.

[0023] Figure 3 This is the SEM-EDS image of the leached slag phase of the ternary lithium battery waste in comparative example 2.

[0024] Figure 4 This is the SEM-EDS image of the leached slag phase of the ternary lithium battery waste in comparative example 3.

[0025] Figure 5 This is the SEM-EDS image of the leached slag phase of the ternary lithium battery waste in comparative example 4. DETAILED DESCRIPTION

[0026] The following examples are provided to facilitate a better understanding of the present invention, but are not intended to limit the present invention. The experimental methods in the following examples are conventional methods unless otherwise specified.

[0027] The principle of the method of the present invention is: the high-valent metal oxides in the waste of ternary lithium batteries are reduced by a reduction roasting method to be converted into low-valent oxides that are beneficial to leaching; and in the reduction process, the reduction temperature is adjusted to control the phase change of the waste, so that the content of lithium aluminate generated in the waste is low, and lithium elements are prevented from remaining in the leaching slag phase. The leaching agent is citric acid, which is safer and more environmentally friendly than inorganic strong acids, and thiourea, an aluminum corrosion inhibitor, is added to inhibit the leaching of aluminum foil materials in the waste in citric acid, thereby achieving the purpose of selectively leaching valuable metal elements in the waste of ternary lithium batteries.

[0028] The method of the present invention for inhibiting the leaching of aluminum element in ternary lithium battery waste is as follows:

[0029] The calcination temperature is adjusted, and the valuable metal elements in the ternary lithium battery waste are reduced by a reduction calcination method, and then cooled. The whole process is carried out under argon protection, and then a leaching agent is added to selectively leach the valuable metal elements in the waste. The leaching agent consists of a citric acid solution and an aluminum corrosion inhibitor thiourea. After filtration, a leaching solution containing lithium, nickel, cobalt and manganese is obtained, and the leached slag phase is the leached slag of the negative electrode graphite material and the current collector aluminum foil.

[0030] When performing reduction treatment, argon gas must be used instead of other gases such as nitrogen or a mixture of nitrogen and hydrogen. This is because:

[0031] (1) There is lithium in the waste material. During the reduction roasting process, the reduced lithium easily reacts with nitrogen at high temperature. This causes nitrogen to enter the leaching solution, which brings inconvenience to the subsequent use of the leaching solution. For example, the nitrogen content in the waste solution is too high and difficult to handle.

[0032] (2) The negative electrode graphite material in the waste material itself is reducible at high temperatures. If hydrogen is used to assist in reduction, the cost will increase, and the use of hydrogen is relatively dangerous, which poses a hidden danger to process safety. Secondly, if hydrogen is used to assist in reduction, the nickel, cobalt, and manganese in the waste material will almost all be reduced to metal elements, and the leaching system of this application is citric acid + aluminum corrosion inhibitor. The leaching efficiency of metal elements in this leaching system is much lower than that of low-valent oxides of metals, which will cause the leaching rate of valuable metals to decrease. The reduction roasting in this application utilizes the reducibility of the negative electrode graphite material, and requires that the reduction reaction is not very severe, so this application only uses argon as a protective gas for roasting.

[0033] Thiourea has a single component, is easily available, is inexpensive, and is an organic substance. It can be decomposed and easily handled during the subsequent waste liquid treatment process of recovering the remaining metal salts by distillation.

[0034] According to some embodiments of the present application, the ternary lithium battery waste is a mixture of ternary lithium battery positive and negative electrode materials and aluminum foil. Before roasting, the ternary lithium battery waste can be pretreated and crushed into powder.

[0035] According to some embodiments of the present application, the reduction roasting is carried out in a vacuum tube rotary furnace or a muffle furnace after evacuation.

[0036] The purpose of vacuuming is to prevent air from entering the furnace and causing oxidation of the sample. In the laboratory, since there is less waste to be burned, there is no difference between using a muffle furnace and a vacuum tube rotary furnace; however, if it is an industrial application, the amount of waste to be processed is large, and since the vacuum tube rotary furnace can rotate, it is beneficial to improve the heat transfer efficiency and enhance the heating effect, so the vacuum tube rotary furnace is more effective.

[0037] According to some embodiments of the present application, the calcination temperature during the reduction calcination is 500-550°C; preferably, the calcination temperature is 520°C-540°C.

[0038] The raw material components used in the present invention contain current collector aluminum foil, and the high-valent metal oxides in the waste of ternary lithium batteries are reduced to low-valent states by utilizing the leaching principle. Selecting 500-550°C can make the reduction reaction more intense. If the roasting temperature is lower than 500°C, the high-valent metal oxide reduction rate in the waste is low, and it is difficult to leach in citric acid. If the roasting temperature is too high (higher than 550°C), the metal element content in the waste is too high, and the reaction rate of nickel and cobalt elements with citric acid is lower than that of their oxides, resulting in a reduction in the leaching rate of valuable metals. At the same time, a certain amount of thiourea corrosion inhibitor is added to the leaching agent, which has a certain corrosion inhibition effect on metal elements, and also causes a reduction in the leaching rate of valuable metals. In addition, the aluminum foil material in the waste material, due to the more intense reduction reaction, generates more carbon dioxide, and the lithium element in the waste material is easy to generate lithium carbonate with carbon dioxide, and lithium carbonate and aluminum foil form lithium aluminate. Since the acidity of the citric acid solution is not as strong as that of inorganic acids such as hydrochloric acid and sulfuric acid, the generated lithium aluminate has poor water solubility and reacts slowly with citric acid. This causes a large amount of lithium to remain in the leaching residue in the form of lithium aluminate, reducing the leaching rate of lithium.

[0039] According to some embodiments of the present application, the gas flow rate during the reduction roasting is 0.5L to 1L / min.

[0040] When the gas flow rate is less than 0.5L / min, the air outside the muffle furnace is easy to enter the furnace, affecting the reduction process of the waste in the furnace. When the gas flow rate is greater than 1L / min, the waste powder is easy to be blown up and taken out of the muffle furnace.

[0041] According to some embodiments of the present application, the reduction roasting time is 2.5-3h.

[0042] If the roasting time is less than 2.5h, the content of high-valent oxides in the waste is high, resulting in a decrease in the leaching efficiency of valuable metal elements; if the roasting time is more than 3h, a large amount of valuable metal elements in the waste are reduced to metal elements, which are not suitable for leaching in citric acid, and a large amount of lithium aluminate is generated, resulting in a decrease in the leaching rate of lithium.

[0043] According to some embodiments of the present application, the cooling is performed naturally under the protection of argon gas, and the gas flow rate during cooling is 0.5L to 1L / min. This can prevent the reduced high-valent metal oxides in the waste from being oxidized again after contacting the air, and avoid contacting with moisture in the air to form hydrates.

[0044] According to some embodiments of the present application, the concentration of the citric acid solution is 2.5-3 mol / L. The preparation method is: weigh 480-576 g of anhydrous citric acid in a container, add 1 L of distilled water at room temperature, stir until the citric acid is completely dissolved, and prepare a 2.5-3 mol / L citric acid solution.

[0045] When the concentration of added citric acid is lower than 2.5 mol / L, the leaching rate of valuable metal elements in the waste will be reduced. When the concentration of added citric acid is higher than 3 mol / L, the leaching rate of valuable metal elements will not increase, and citric acid will be wasted.

[0046] According to some embodiments of the present application, the liquid-to-solid ratio of the citric acid solution to the ternary lithium battery waste is 15-20 mL / g.

[0047] The above liquid-to-solid ratio is selected based on the metal element content in the waste. Generally, 50% excess acid ensures leaching efficiency. Too high solid content will reduce leaching efficiency, and too low solid content will cause waste of acid.

[0048] According to some embodiments of the present application, the added amount of the aluminum corrosion inhibitor thiourea is 0.1%-0.3% of the total mass of the ternary lithium battery waste and the citric acid solution.

[0049] When the mass of thiourea added is higher than 0.3% of the total mass of the ternary lithium battery waste and the citric acid solution, other metal elements in the waste are easily chemically adsorbed, thereby reducing the leaching rate; when the mass of thiourea added is lower than 0.1% of the total mass of the ternary lithium battery waste and the citric acid solution, the leaching rate of aluminum increases, and the purpose of inhibiting the leaching of aluminum elements cannot be achieved.

[0050] According to some embodiments of the present application, when the leaching agent is added for leaching, the leaching time is 2.5-3 hours.

[0051] If the leaching time is less than 2.5h, the leaching rate of the target metal element will decrease. If the leaching time is longer than 3h, the leaching rate will remain basically unchanged, which will increase energy consumption.

[0052] According to some embodiments of the present application, leaching is performed under stirring conditions. The present application does not limit the stirring speed, as long as the materials can be fully mixed.

[0053] The present invention does not limit the specific filtering method, and commonly used filtering methods in the prior art, such as pressure filtration, suction filtration, etc., can be used.

[0054] By applying the method of the present invention, the leaching rates of lithium, nickel, cobalt and manganese elements are all higher than 95%, and the leaching rate of aluminum element is lower than 1%.

[0055] Example 1

[0056] The method of the present invention for inhibiting the leaching of aluminum element in ternary lithium battery waste is as follows:

[0057] Select ternary lithium battery waste powder (mixed powder of positive electrode, negative electrode and aluminum foil), weigh a certain amount of ternary lithium battery waste and place it in a vacuum muffle furnace. After evacuation, introduce argon gas at a flow rate of 1 L / min, adjust the roasting temperature to 520°C, and reduce roast the powdered ternary lithium battery waste for 2.5 h. The roasted material is naturally cooled to room temperature in an argon atmosphere at a flow rate of 1 L / min.

[0058] The cooled ternary lithium battery waste, citric acid solution and aluminum corrosion inhibitor thiourea are placed in a leaching reactor and mixed, and the valuable metal elements are leached out by stirring. Among them, the citric acid solution and the aluminum corrosion inhibitor thiourea are used together as leaching agents; the concentration of the citric acid solution is 3 mol / L, the liquid-solid ratio of the citric acid solution to the waste is 20 mL / g, and the amount of thiourea added is 0.3% of the total mass of the ternary lithium battery waste and the citric acid solution. After leaching for 3 hours, the leachate and the leach residue are obtained by filtration. The leachate is detected by ICP, and the dissolution rates of lithium, nickel, cobalt, and manganese are calculated to be 95.41%, 95.74%, 95.65%, and 99.50%; the dissolution rate of aluminum is 0.72%.

[0059] Figure 1 This is the SEM-EDS image of the residual slag phase after leaching of the ternary lithium battery waste after reduction roasting in Example 1.

[0060] Depend on Figure 1 It can be seen that the method of the present invention can show that the slag phase after leaching is mainly composed of graphite and aluminum elements, thereby achieving the purpose of selective leaching.

[0061] Example 2

[0062] The method of the present invention for inhibiting the leaching of aluminum element in ternary lithium battery waste is as follows:

[0063] Select ternary lithium battery waste powder (mixed powder of positive electrode, negative electrode and aluminum foil), weigh a certain amount of ternary lithium battery waste and place it in a vacuum muffle furnace. After evacuation, introduce argon gas at a flow rate of 0.8 L / min, adjust the roasting temperature to 530°C, and reduce and roast the powdered ternary lithium battery waste for 3 hours; the roasted material is naturally cooled to room temperature in an argon atmosphere at a flow rate of 0.8 L / min.

[0064] The cooled ternary lithium battery waste, citric acid solution and aluminum corrosion inhibitor thiourea are placed in a leaching reactor and mixed, and the valuable metal elements are leached out by stirring. Among them, the citric acid solution and the aluminum corrosion inhibitor thiourea are used together as leaching agents; the concentration of the citric acid solution is 2.5 mol / L, the liquid-solid ratio of the citric acid solution to the waste is 20 mL / g, and the amount of thiourea added is 0.2% of the total mass of the ternary lithium battery waste and the citric acid solution. After leaching for 3 hours, the leachate and the leach residue are obtained by filtration. The leachate is detected by ICP, and the dissolution rates of lithium, nickel, cobalt, and manganese are calculated to be 95.55%, 96.41%, 96.25%, and 99.11%; the dissolution rate of aluminum is 0.67%.

[0065] Example 3

[0066] The method of the present invention for inhibiting the leaching of aluminum element in ternary lithium battery waste is as follows:

[0067] Select ternary lithium battery waste powder (mixed powder of positive electrode, negative electrode and aluminum foil), weigh a certain amount of ternary lithium battery waste and place it in a vacuum muffle furnace. After evacuation, introduce argon gas at a flow rate of 0.5L / min, adjust the roasting temperature to 540°C, and reduce roast the powdered ternary lithium battery waste for 2.5h. The roasted material is naturally cooled to room temperature in an argon atmosphere at a flow rate of 0.5L / min.

[0068] The cooled ternary lithium battery waste, citric acid solution and aluminum corrosion inhibitor thiourea are placed in a leaching reactor and mixed, and the valuable metal elements are leached out by stirring. Among them, the citric acid solution and the aluminum corrosion inhibitor thiourea are used together as leaching agents; the concentration of the citric acid solution is 3 mol / L, the liquid-solid ratio of the citric acid solution to the waste is 20 mL / g, and the amount of thiourea added is 0.1% of the total mass of the ternary lithium battery waste and the citric acid solution. After leaching for 3 hours, the leachate and the leach residue are obtained by filtration. The leachate is detected by ICP, and the dissolution rates of lithium, nickel, cobalt, and manganese are calculated to be 96.95%, 95.82%, 95.36%, and 98.70%; the dissolution rate of aluminum is 0.82%.

[0069] Comparative Example 1

[0070] The difference between this comparative example and Example 1 is that the calcination temperature is 420° C., and the other steps and parameters are the same as those in Example 1.

[0071] The leaching solution was detected by ICP, and the dissolution rates of lithium, nickel, cobalt and manganese were calculated to be 96.41%, 92.65%, 90.77% and 95.50% respectively; the dissolution rate of aluminum element was 0.64%.

[0072] Figure 2 This is the SEM-EDS image of the leached slag phase of the ternary lithium battery waste in comparative example 1.

[0073] Comparative Example 2

[0074] The difference between this comparative example and Example 1 is that the calcination temperature is 590° C., and the other steps and parameters are the same as those in Example 1.

[0075] The leachate was detected by ICP, and the dissolution rates of lithium, nickel, cobalt and manganese were calculated to be 90.33%, 84.25%, 85.64% and 92.58% respectively; the dissolution rate of aluminum was 0.53%.

[0076] Figure 3 This is the SEM-EDS image of the leached slag phase of the ternary lithium battery waste in comparative example 2.

[0077] After reduction roasting in Examples 1-3, the valuable metal elements in the ternary lithium battery waste are transformed from a high valence state to a low valence state, and the leaching effect in the organic acid citric acid is excellent, and the leaching rate is above 95%. In Comparative Example 1, due to insufficient roasting temperature, the valence reduction layer of the valuable metal elements in the waste after reduction roasting is insufficient, resulting in a lower leaching rate of the valuable metal elements than in Examples 1-3.

[0078] In Comparative Example 2, since the reduction roasting temperature is too high, most of the nickel element is reduced to a single substance. Since the reaction rate of the single substance of nickel and cobalt in the citric acid leaching agent is lower than that of its oxide, and the added aluminum corrosion inhibitor thiourea may chemically adsorb the metal single substance, the leaching rate of nickel and cobalt elements is reduced. In addition, the high reduction temperature helps the lithium element to form insoluble lithium aluminate with the aluminum foil material, resulting in a reduced leaching rate of the lithium element.

[0079] It can be concluded from the above experimental results that the present invention is used to reduce and roast the ternary lithium battery waste before leaching, which is beneficial for the valuable metal elements in the waste to be leached in safe and environmentally friendly citric acid; if the roasting temperature is higher or lower than the range specified by the present invention, the leaching effect is not good. Therefore, the present invention has good engineering application value, economic value and environmental value.

[0080] Comparative Example 3

[0081] The difference between this comparative example and Example 1 is that during leaching, only citric acid solution is added to the waste material without adding aluminum corrosion inhibitor thiourea, and the remaining steps and parameters are the same as those in Example 1.

[0082] The leaching solution was detected by ICP, and the dissolution rates of lithium, nickel, cobalt and manganese were calculated to be 97.41%, 98.74%, 96.65% and 99.37% respectively; the dissolution rate of aluminum element was 3.25%.

[0083] Figure 4 This is the SEM-EDS image of the leached slag phase of the ternary lithium battery waste in comparative example 3.

[0084] Comparative Example 4

[0085] The difference between this comparative example and Example 1 is that the amount of thiourea added is 0.4% of the total mass of the ternary lithium battery waste and the citric acid solution, and the remaining steps and parameters are the same as those in Example 1.

[0086] The leaching solution was detected by ICP, and the dissolution rates of lithium, nickel, cobalt and manganese were calculated to be 95.41%, 93.55%, 93.82% and 99.58% respectively; the dissolution rate of aluminum element was 0.49%.

[0087] Figure 5 This is the SEM-EDS image of the leached slag phase of the ternary lithium battery waste in comparative example 4.

[0088] Compared with comparative examples 3-4, examples 1-3 show that when thiourea, an aluminum corrosion inhibitor, is not added, the aluminum leaching rate is higher than 1%; when an excessive amount of thiourea, an aluminum corrosion inhibitor, is added, thiourea, an aluminum corrosion inhibitor, also inhibits the leaching of nickel and cobalt in the waste under the action of chemical adsorption, and the leaching rates of nickel and cobalt are lower than 95%.

[0089] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for inhibiting the leaching of aluminum from ternary lithium battery waste, characterized in that: The valuable metal elements in the ternary lithium battery waste are reduced by a reduction roasting method, and then cooled. The whole process is carried out under argon protection. Subsequently, a leaching agent is added to selectively leach the valuable metal elements in the waste. The leaching agent is composed of a citric acid solution and an aluminum corrosion inhibitor thiourea. After filtering, a leaching solution containing lithium, nickel, cobalt, and manganese and a leaching residue containing a negative electrode graphite material and a current collector aluminum foil are obtained; The reduction roasting temperature is 500-550°C, and the reduction roasting time is 2.5-3h; The gas flow rate during the reduction roasting and cooling is 0.5L-1L / min; The concentration of the citric acid solution is 2.5-3 mol / L; The liquid-to-solid ratio of the citric acid solution to the ternary lithium battery waste is 15-20 mL / g; The amount of thiourea, an aluminum corrosion inhibitor, added is 0.1%-0.3% of the total mass of the ternary lithium battery waste and the citric acid solution; When adding the leaching agent for leaching, the leaching time is 2.5-3h; The leaching rate of aluminum element in the leaching solution is less than 1%.

2. The method according to claim 1, characterized in that: The ternary lithium battery waste is a mixture of ternary lithium battery positive and negative electrode materials and aluminum foil, and / or The ternary lithium battery waste is in powder form.

3. The method according to claim 1, characterized in that: The reduction roasting is carried out in a vacuum tube rotary furnace or a muffle furnace after evacuation.

4. The method according to claim 1, characterized in that: The calcination temperature during the reduction calcination is 520°C-540°C.

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