A method for recycling valuable metals from power batteries of new energy vehicles

Abstract

This invention relates to the field of lithium-ion battery recycling technology, specifically to a method for recovering valuable metals from new energy vehicle power batteries. The method involves discharging and disassembling spent new energy vehicle power batteries to separate the positive electrode; the positive electrode is then reduced and roasted to obtain lithium carbonate and metallic nickel, cobalt, and manganese; the roasted product is added to a carbonated solution to obtain a lithium-containing solution and leaching residue; CO2 is continuously introduced into the lithium-containing solution to convert lithium carbonate into lithium bicarbonate, which is then filtered and heated to obtain battery-grade lithium carbonate; the leaching residue is dissolved in an acidic solution to form a leachate, and the resulting purified nickel, cobalt, and manganese solution is used to prepare a ternary cathode material precursor. This invention combines wet and pyrometallurgical processes to recover valuable metals from new energy vehicle power batteries, achieving not only high recovery rates of lithium, nickel, cobalt, and manganese, but also high purity of the lithium carbonate and nickel-cobalt-manganese ternary cathode materials.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery recycling technology, specifically to a method for recycling valuable metals from power batteries of new energy vehicles. Background Technology

[0002] With the rapid development of the new energy vehicle industry and the widespread application of ternary lithium-ion batteries in automobiles, the problem of recycling retired lithium-ion batteries is becoming increasingly serious. Solving the problem of recycling retired lithium-ion batteries is of great significance to resource recycling and environmental protection.

[0003] Currently, traditional recycling methods mainly include pyrometallurgical processes and hydrometallurgical processes. Pyrometallurgical processes have a short process flow and can directly recover valuable metals, but it is difficult to produce high-purity products. At the same time, there are environmental problems such as the need for flue gas purification. Faced with increasingly stringent environmental requirements, the application scope of pyrometallurgical processes is becoming smaller and smaller. Hydrometallurgical processes can obtain high-purity products, but their process flow is long, the recovery rate of valuable metals is low and difficult to separate, and a large amount of industrial wastewater is generated, which also faces significant environmental pressure. Summary of the Invention

[0004] Therefore, the purpose of this invention is to provide a combined wet and pyrometallurgical process to recover lithium and nickel-cobalt-manganese from the power batteries of new energy vehicles, and to further process them to produce battery-grade lithium carbonate and ternary cathode material precursors. This method is safe, environmentally friendly, low-cost, highly efficient, and has a high recovery rate of valuable metals.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for recycling valuable metals from power batteries of new energy vehicles includes the following steps:

[0007] S1 discharges and disassembles used batteries, separating the positive electrode;

[0008] S2 grinds and pulverizes the positive electrode, adds calcination aid and carbon reducing agent and mixes them thoroughly, then reduces and calcines it to obtain a mixture of metallic nickel, metallic cobalt, metallic manganese and lithium carbonate;

[0009] S3 The mixture is added to a carbonic acid solution, and CO2 is continuously introduced to convert lithium carbonate into lithium bicarbonate, thereby separating lithium from other metals and obtaining a lithium-containing solution and leaching residue.

[0010] S4 Heat the lithium-containing solution to convert lithium bicarbonate into lithium carbonate, obtain lithium carbonate crystals, filter and dry to obtain battery-grade lithium carbonate;

[0011] S5. The leaching residue is added to an acidic solution to dissolve and form a leachate;

[0012] S6. The leachate is passed through a selective resin to obtain a purified nickel-cobalt-manganese solution;

[0013] S7 uses the nickel-cobalt-manganese purified solution to prepare a ternary cathode material precursor.

[0014] This invention separates the positive electrode from the power battery of a new energy vehicle by discharging and disassembling it. The positive electrode is then ground and mixed with a calcination aid and a carbon reducing agent, followed by reduction calcination to obtain lithium carbonate, which is easily soluble in carbonic acid, and metallic nickel, cobalt, and manganese, which are insoluble in carbonic acid. The calcination product is added to a carbonic acid solution to obtain a lithium-containing solution and a leaching residue. CO2 is continuously introduced into the lithium-containing solution to convert lithium carbonate into lithium bicarbonate, maximizing the dissolution of lithium in the solution. After filtration, the lithium-containing solution can be heated to obtain battery-grade lithium carbonate. The leaching residue can be dissolved in an acidic solution to form a leachate, which is a lithium-containing nickel-cobalt-manganese solution. The leachate is then adsorbed using resin to remove any remaining small amount of lithium. The resulting purified nickel-cobalt-manganese solution can be directly used to prepare a ternary cathode material precursor. By combining wet and pyrometallurgical processes, lithium is selectively extracted during recovery, directly yielding battery-grade lithium carbonate. The purified nickel-cobalt-manganese solution directly prepares the ternary cathode material precursor, eliminating multiple extraction and separation steps and achieving efficient recovery of valuable metals, especially lithium, nickel, cobalt, and manganese, from new energy vehicle power batteries. Compared with the pyrometallurgical process, this recovery method yields products with higher purity, and the process is safer, more environmentally friendly, and lower in cost. Compared with the hydrometallurgical process, this recovery method has milder reaction conditions, does not require strong acid to dissolve metals, and does not require multi-step extraction and separation, thus reducing reaction steps, improving efficiency, and achieving a high recovery rate of valuable metals.

[0015] As a preferred embodiment, the calcination aid described in this invention is one or both of ammonium chloride and calcium chloride. Calcium chloride not only lowers the calcination temperature but also exhibits higher selectivity for lithium after calcination, thereby improving lithium recovery. Ammonium chloride can further lower the calcination temperature and reduce energy consumption during the calcination process.

[0016] As a preferred embodiment, the mass of the carbon reducing agent in this invention is 15-30% of the mass of the positive electrode, and the mass of the calcination aid is 10-20% of the mass of the positive electrode. If the mass ratio of the carbon reducing agent to the positive electrode is too low, the reaction will be incomplete, resulting in a low recovery rate of valuable metals. If the mass ratio is too high, it will not significantly improve the recovery rate of valuable metals and will increase costs. If the mass ratio of the calcination aid to the positive electrode is too low, it will not achieve the goal of reducing the calcination temperature. If the mass ratio is too high, it will not significantly reduce the calcination temperature and will increase production costs.

[0017] As a preferred embodiment, the reduction roasting of the present invention is carried out in two steps. The first roasting temperature is 300-350℃, and the time is 0.5-2 hours. During this time and temperature, the carbon reducing agent is activated and converted into amorphous carbon, while the roasting aid begins to decompose. The second roasting temperature is 700-900℃, and the roasting time is 3-6 hours. During this time and temperature, the carbon reducing agent can destroy the cathode structure and reduce the lithium, nickel, cobalt, and manganese therein to obtain lithium carbonate, metallic nickel, metallic cobalt, and metallic manganese. The reduction roasting is carried out under an inert atmosphere to ensure that the reduction roasting achieves the desired effect.

[0018] As a preferred embodiment, after the carbonated solution is added to the mixture, CO2 is continuously introduced to adjust the pH to 4.0-5.0. Within this pH range, lithium carbonate can be converted to lithium bicarbonate to the greatest extent, and lithium bicarbonate has the highest solubility under these conditions, resulting in a higher lithium recovery rate. The inventors discovered that the lithium recovery rate, reaching 96%, is highest at pH 4.5.

[0019] As a preferred embodiment, step S4 of this invention further includes stirring the solution while heating, with the heating temperature at 40-100℃ and the heating time at 1-2 hours. Stirring during heating yields lithium carbonate particles with a small particle size; if the heating temperature is too high, the lithium carbonate may stick to the container wall, which is detrimental to subsequent processing; if the heating temperature is too low, it is not conducive to the decomposition of lithium bicarbonate, resulting in a longer reaction time; if the heating time is too short, the lithium bicarbonate may not decompose completely, resulting in low purity lithium carbonate; if the heating time is too long, it wastes energy. The lithium carbonate obtained by this method has a high purity, reaching over 99%.

[0020] As a preferred embodiment, step S5 of the present invention further includes microwave heating or ultrasonic heating, with a heating temperature of 60-100℃ and a heating time of 5-30 minutes. Microwave heating or ultrasonic heating has advantages such as uniform heating, fast heating speed, energy saving, and even improvement of material properties. It can significantly shorten acid leaching time and reduce acid leaching temperature, and can also improve leaching efficiency.

[0021] As a preferred embodiment, the acidic solution of the present invention is one or more of oxalic acid, citric acid, ascorbic acid, malic acid, and gluconic acid. The acidic solution is widely available, low in cost, and easy to process. The concentration of the acidic solution is 0.1-1.5 mol / L. Too low a concentration will result in a low leaching rate of nickel, cobalt, and manganese metals, while too high a concentration will require advanced equipment and increase production costs.

[0022] As a preferred embodiment, step S7 of the present invention further includes adding one or more of nickel salts, cobalt salts, and manganese salts to the nickel-cobalt-manganese purification solution, adjusting the nickel-cobalt-manganese ion concentration ratio to achieve the composition ratio required for ternary batteries; adding alkaline solution to adjust the pH to 10-13, filtering, washing, and drying to obtain the nickel-cobalt-manganese ternary precursor material. Too high a pH places high demands on equipment and increases production costs, while too low a pH results in poor dissolution of nickel-cobalt-manganese. The ternary cathode material precursor obtained by this method has high purity, reaching over 96%. Detailed Implementation

[0023] The present invention discloses a method for recycling valuable metals from power batteries of new energy vehicles, comprising the following steps:

[0024] S1 discharges and disassembles used batteries, separating the positive electrode;

[0025] S2 grinds and pulverizes the positive electrode, adds calcination aid and carbon reducing agent and mixes them thoroughly, then reduces and calcines it to obtain a mixture of metallic nickel, metallic cobalt, metallic manganese and lithium carbonate;

[0026] S3 The mixture is added to a carbonic acid solution, and CO2 is continuously introduced to convert lithium carbonate into lithium bicarbonate, thereby separating lithium from other metals and obtaining a lithium-containing solution and leaching residue.

[0027] S4 Heat the lithium-containing solution to convert lithium bicarbonate into lithium carbonate, obtain lithium carbonate crystals, filter and dry to obtain battery-grade lithium carbonate;

[0028] S5. The leaching residue is added to an acidic solution to dissolve and form a leachate;

[0029] S6. The leachate is passed through a selective resin to obtain a purified nickel-cobalt-manganese solution;

[0030] S7 uses the nickel-cobalt-manganese purified solution to prepare a ternary cathode material precursor.

[0031] This invention separates the positive electrode from the power battery of a new energy vehicle by discharging and disassembling it. The positive electrode is then ground and mixed with a calcination aid and a carbon reducing agent, followed by reduction calcination to obtain lithium carbonate, which is easily soluble in carbonic acid, and metallic nickel, cobalt, and manganese, which are insoluble in carbonic acid. The calcination product is added to a carbonic acid solution to obtain a lithium-containing solution and a leaching residue. CO2 is continuously introduced into the lithium-containing solution to convert lithium carbonate into lithium bicarbonate, maximizing the dissolution of lithium in the solution. After filtration, the lithium-containing solution can be heated to obtain battery-grade lithium carbonate. The leaching residue can be dissolved in an acidic solution to form a leachate, which is a lithium-containing nickel-cobalt-manganese solution. The leachate is then adsorbed using resin to remove any remaining small amount of lithium. The resulting purified nickel-cobalt-manganese solution can be directly used to prepare a ternary cathode material precursor. By combining wet and pyrometallurgical processes, lithium is selectively extracted during recovery, directly yielding battery-grade lithium carbonate. The purified nickel-cobalt-manganese solution directly prepares the ternary cathode material precursor, eliminating multiple extraction and separation steps and achieving efficient recovery of valuable metals, especially lithium, nickel, cobalt, and manganese, from new energy vehicle power batteries. Compared with the pyrometallurgical process, this recovery method yields products with higher purity, and the process is safer, more environmentally friendly, and lower in cost. Compared with the hydrometallurgical process, this recovery method has milder reaction conditions, does not require strong acid to dissolve metals, and does not require multi-step extraction and separation, thus reducing reaction steps, improving efficiency, and achieving a high recovery rate of valuable metals.

[0032] Example 1

[0033] The present invention discloses a method for recycling valuable metals from power batteries of new energy vehicles, comprising the following steps:

[0034] S1 discharges and disassembles used batteries, separating the positive electrode;

[0035] S2 grinds and pulverizes the positive electrode, adds calcium chloride and carbon reducing agent and mixes them thoroughly, wherein the mass of calcium chloride is 10% of the mass of the positive electrode and the mass of carbon reducing agent is 15% of the mass of the positive electrode; then it is reduced and calcined under an inert atmosphere. The first step of reduction and calcination is at a temperature of 300°C for 2 hours, and the second step is at a temperature of 800°C for 6 hours. After calcination, a mixture of metallic nickel, metallic cobalt, metallic manganese and lithium carbonate is obtained.

[0036] S3 adds the mixture to a carbonic acid solution, and continuously introduces CO2 to adjust the pH to 4.0, converting lithium carbonate into lithium bicarbonate, separating lithium from other metals, and obtaining a lithium-containing solution and leaching residue;

[0037] S4 The lithium-containing solution is heated at 40°C for 2 hours with stirring to convert lithium bicarbonate into lithium carbonate, resulting in lithium carbonate crystals. After filtration and drying, battery-grade lithium carbonate is obtained.

[0038] S5 The leaching residue is added to a mixed solution of oxalic acid and citric acid, wherein the concentration of oxalic acid is 0.5 mol / L and the concentration of citric acid is 0.2 mol / L. Ultrasonic heating is then applied at a temperature of 80°C for 10 minutes to dissolve and form a leaching solution, which is a lithium-containing nickel-cobalt-manganese solution.

[0039] S6 The leachate is passed through a selective resin to adsorb lithium, resulting in a purified nickel-cobalt-manganese solution;

[0040] S7 adds one or more of nickel salt, cobalt salt, and manganese salt to the nickel-cobalt-manganese purification solution to make the molar ratio of nickel-cobalt-manganese ions in the solution 8:1:1, adjusts the pH to 11, filters, washes and dries to obtain the nickel-cobalt-manganese ternary precursor material.

[0041] The lithium recovery rate after treatment using this method was 93.2%, the nickel-cobalt-manganese recovery rate was 96.6%, the purity of lithium carbonate was 99.4%, and the purity of the nickel-cobalt-manganese ternary cathode material precursor was 97.8%.

[0042] Example 2

[0043] The present invention discloses a method for recycling valuable metals from power batteries of new energy vehicles, comprising the following steps:

[0044] S1 discharges and disassembles used batteries, separating the positive electrode;

[0045] S2 grinds and pulverizes the positive electrode, adds calcium chloride and carbon reducing agent and mixes them thoroughly, wherein the mass of calcium chloride is 15% of the mass of the positive electrode and the mass of carbon reducing agent is 25% of the mass of the positive electrode; then it is reduced and calcined under an inert atmosphere. The first step of reduction and calcination is at a temperature of 320°C for 1.5 hours, and the second step is at a temperature of 850°C for 5 hours. After calcination, a mixture of metallic nickel, metallic cobalt, metallic manganese and lithium carbonate is obtained.

[0046] S3 adds the mixture to a carbonic acid solution, and continuously introduces CO2 to adjust the pH to 4.3, converting lithium carbonate into lithium bicarbonate, separating lithium from other metals, and obtaining a lithium-containing solution and leaching residue;

[0047] S4 The lithium-containing solution is heated at 50°C for 2 hours with stirring to convert lithium bicarbonate into lithium carbonate, resulting in lithium carbonate crystals. After filtration and drying, battery-grade lithium carbonate is obtained.

[0048] S5 The leaching residue is added to a mixed solution of oxalic acid and ascorbic acid, wherein the concentration of oxalic acid is 0.5 mol / L and the concentration of ascorbic acid is 0.5 mol / L. Ultrasonic heating is then applied at a temperature of 70°C for 20 minutes to dissolve and form a leaching solution, which is a lithium-containing nickel-cobalt-manganese solution.

[0049] S6 The leachate is passed through a selective resin to adsorb lithium, resulting in a purified nickel-cobalt-manganese solution;

[0050] S7 adds one or more of nickel salt, cobalt salt, and manganese salt to the nickel-cobalt-manganese purification solution to make the molar ratio of nickel-cobalt-manganese ions in the solution 8:1:1, adjusts the pH to 12, filters, washes and dries to obtain the nickel-cobalt-manganese ternary precursor material.

[0051] The lithium recovery rate after treatment using this method was 94.5%, the nickel-cobalt-manganese recovery rate was 97.8%, the purity of lithium carbonate was 99.6%, and the purity of the nickel-cobalt-manganese ternary cathode material precursor was 98.3%.

[0052] Example 3

[0053] The present invention discloses a method for recycling valuable metals from power batteries of new energy vehicles, comprising the following steps:

[0054] S1 discharges and disassembles used batteries, separating the positive electrode;

[0055] S2 grinds and pulverizes the positive electrode, adds calcium chloride and carbon reducing agent and mixes them thoroughly, wherein the mass of calcium chloride is 20% of the mass of the positive electrode and the mass of carbon reducing agent is 30% of the mass of the positive electrode; then it is reduced and calcined under an inert atmosphere. The first step of reduction and calcination is at a temperature of 350°C for 1.5 hours, and the second step is at a temperature of 900°C for 4 hours. After calcination, a mixture of metallic nickel, metallic cobalt, metallic manganese and lithium carbonate is obtained.

[0056] S3 adds the mixture to a carbonic acid solution, and continuously introduces CO2 to adjust the pH to 4.5, converting lithium carbonate into lithium bicarbonate, separating lithium from other metals, and obtaining a lithium-containing solution and leaching residue;

[0057] S4 The lithium-containing solution is heated at 90°C for 1 hour with stirring to convert lithium bicarbonate into lithium carbonate, resulting in lithium carbonate crystals. After filtration and drying, battery-grade lithium carbonate is obtained.

[0058] S5 The leaching residue is added to a mixed solution of oxalic acid and malic acid, wherein the concentration of oxalic acid is 0.5 mol / L and the concentration of malic acid is 0.3 mol / L. Ultrasonic heating is then applied at a temperature of 80°C for 10 minutes to dissolve and form a leaching solution, which is a lithium-containing nickel-cobalt-manganese solution.

[0059] S6 The leachate is passed through a selective resin to adsorb lithium, resulting in a purified nickel-cobalt-manganese solution;

[0060] S7 adds one or more of nickel salt, cobalt salt, and manganese salt to the nickel-cobalt-manganese purification solution to make the molar ratio of nickel-cobalt-manganese ions in the solution 8:1:1, adjusts the pH to 12, filters, washes and dries to obtain the nickel-cobalt-manganese ternary precursor material.

[0061] After treatment using this method, the lithium recovery rate was 96%, the nickel-cobalt-manganese recovery rate was 97.7%, the purity of lithium carbonate was 99.6%, and the purity of the nickel-cobalt-manganese ternary cathode material precursor was 97.7%.

[0062] Example 4

[0063] The present invention discloses a method for recycling valuable metals from power batteries of new energy vehicles, comprising the following steps:

[0064] S1 discharges and disassembles used batteries, separating the positive electrode;

[0065] S2 grinds and pulverizes the positive electrode, adds calcium chloride, ammonium chloride, and carbon reducing agent, and mixes them thoroughly. The mass of calcium chloride is 10% of the mass of the positive electrode, the mass of ammonium chloride is 10% of the mass of the positive electrode, and the mass of carbon reducing agent is 20% of the mass of the positive electrode. Then, it is reduced and calcined under an inert atmosphere. The first step of the reduction and calcination is at a temperature of 300°C for 1 hour, and the second step is at a temperature of 750°C for 3 hours. After calcination, a mixture of metallic nickel, metallic cobalt, metallic manganese, and lithium carbonate is obtained.

[0066] S3 adds the mixture to a carbonic acid solution, and continuously introduces CO2 to adjust the pH to 4.8, converting lithium carbonate into lithium bicarbonate, separating lithium from other metals, and obtaining a lithium-containing solution and leaching residue;

[0067] S4 The lithium-containing solution is heated at 100°C for 1 hour with stirring to convert lithium bicarbonate into lithium carbonate, resulting in lithium carbonate crystals. After filtration and drying, battery-grade lithium carbonate is obtained.

[0068] S5 The leaching residue is added to a mixed solution of oxalic acid and gluconic acid, wherein the concentration of oxalic acid is 0.5 mol / L and the concentration of gluconic acid is 0.8 mol / L. Ultrasonic heating is then applied at a temperature of 60°C for 8 minutes to dissolve and form a leaching solution, which is a lithium-containing nickel-cobalt-manganese solution.

[0069] S6 The leachate is passed through a selective resin to adsorb lithium, resulting in a purified nickel-cobalt-manganese solution;

[0070] S7 adds one or more of nickel salt, cobalt salt, and manganese salt to the nickel-cobalt-manganese purification solution to make the molar ratio of nickel-cobalt-manganese ions in the solution 7:2:1, adjusts the pH to 13, filters, washes and dries to obtain the nickel-cobalt-manganese ternary precursor material.

[0071] The lithium recovery rate after treatment using this method was 94.1%, the nickel-cobalt-manganese recovery rate was 95.9%, the purity of lithium carbonate was 99.5%, and the purity of the nickel-cobalt-manganese ternary cathode material precursor was 98.2%.

[0072] Example 5

[0073] The present invention discloses a method for recycling valuable metals from power batteries of new energy vehicles, comprising the following steps:

[0074] S1 discharges and disassembles used batteries, separating the positive electrode;

[0075] S2 grinds and pulverizes the positive electrode, adds calcium chloride, ammonium chloride, and carbon reducing agent, and mixes them thoroughly. The mass of calcium chloride is 10% of the mass of the positive electrode, the mass of ammonium chloride is 10% of the mass of the positive electrode, and the mass of carbon reducing agent is 25% of the mass of the positive electrode. Then, it is reduced and calcined under an inert atmosphere. The first step of reduction and calcination is at a temperature of 300°C for 1 hour, and the second step is at a temperature of 700°C for 3.5 hours. After calcination, a mixture of metallic nickel, metallic cobalt, metallic manganese, and lithium carbonate is obtained.

[0076] S3 adds the mixture to a carbonic acid solution, and continuously introduces CO2 to adjust the pH to 5.0, converting lithium carbonate into lithium bicarbonate, separating lithium from other metals, and obtaining a lithium-containing solution and leaching residue;

[0077] S4 The lithium-containing solution is heated at 60°C for 1.5 hours with stirring to convert lithium bicarbonate into lithium carbonate, resulting in lithium carbonate crystals. After filtration and drying, battery-grade lithium carbonate is obtained.

[0078] S5 The leaching residue is added to a citric acid solution with a concentration of 0.1 mol / L, and then ultrasonically heated at a temperature of 100°C for 30 minutes to dissolve and form a leaching solution, which is a lithium-containing nickel-cobalt-manganese solution.

[0079] S6 The leachate is passed through a selective resin to adsorb lithium, resulting in a purified nickel-cobalt-manganese solution;

[0080] S7 adds one or more of nickel salt, cobalt salt, and manganese salt to the nickel-cobalt-manganese purification solution to make the molar ratio of nickel-cobalt-manganese ions in the solution 7:2:1, adjusts the pH to 12, filters, washes and dries to obtain the nickel-cobalt-manganese ternary precursor material.

[0081] The lithium recovery rate after treatment by this method was 94.4%, the nickel-cobalt-manganese recovery rate was 94.5%, the purity of lithium carbonate was 99.2%, and the purity of the nickel-cobalt-manganese ternary cathode material precursor was 96.7%.

[0082] Example 6

[0083] The present invention discloses a method for recycling valuable metals from power batteries of new energy vehicles, comprising the following steps:

[0084] S1 discharges and disassembles used batteries, separating the positive electrode;

[0085] S2 grinds and pulverizes the positive electrode, adds calcium chloride, ammonium chloride, and carbon reducing agent, and mixes them thoroughly. The mass of calcium chloride is 10% of the mass of the positive electrode, the mass of ammonium chloride is 10% of the mass of the positive electrode, and the mass of carbon reducing agent is 20% of the mass of the positive electrode. Then, it is reduced and calcined under an inert atmosphere. The first step of reduction and calcination is at a temperature of 320°C for 0.5 hours, and the second step is at a temperature of 730°C for 3 hours. After calcination, a mixture of metallic nickel, metallic cobalt, metallic manganese, and lithium carbonate is obtained.

[0086] S3 adds the mixture to a carbonic acid solution, and continuously introduces CO2 to adjust the pH to 4.5, converting lithium carbonate into lithium bicarbonate, separating lithium from other metals, and obtaining a lithium-containing solution and leaching residue;

[0087] S4 The lithium-containing solution is heated at 90°C for 1 hour with stirring to convert lithium bicarbonate into lithium carbonate, resulting in lithium carbonate crystals. After filtration and drying, battery-grade lithium carbonate is obtained.

[0088] S5 The leaching residue is added to a citric acid solution with a concentration of 1.5 mol / L, and then microwave-heated at a temperature of 60°C for 5 minutes to dissolve and form a leaching solution, which is a lithium-containing nickel-cobalt-manganese solution.

[0089] S6 The leachate is passed through a selective resin to adsorb lithium, resulting in a purified nickel-cobalt-manganese solution;

[0090] S7 adds one or more of nickel salt, cobalt salt, and manganese salt to the nickel-cobalt-manganese purification solution to make the molar ratio of nickel-cobalt-manganese ions in the solution 5:2:3, adjusts the pH to 12, filters, washes and dries to obtain the nickel-cobalt-manganese ternary precursor material.

[0091] After treatment using this method, the lithium recovery rate was 96%, the nickel-cobalt-manganese recovery rate was 98.4%, the purity of lithium carbonate was 99.2%, and the purity of the nickel-cobalt-manganese ternary cathode material precursor was 96.1%.

[0092] The above-described embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A method for recycling valuable metals from power batteries of new energy vehicles, comprising the following steps: S1 discharges and disassembles used batteries, separating the positive electrode; S2 grinds and pulverizes the positive electrode, adds calcination aid and carbon reducing agent and mixes them thoroughly, then reduces and calcines it to obtain a mixture after calcination; S3 The mixture is added to a carbonic acid solution, and CO2 is continuously introduced to convert lithium carbonate into lithium bicarbonate, thereby separating lithium from other metals and obtaining a lithium-containing solution and leaching residue. S4 Heat the lithium-containing solution to convert lithium bicarbonate into lithium carbonate, obtain lithium carbonate crystals, filter and dry to obtain battery-grade lithium carbonate; S5. The leaching residue is added to an acidic solution to dissolve and form a leachate; S6. The leachate is passed through a selective resin to obtain a purified nickel-cobalt-manganese solution; S7 uses the nickel-cobalt-manganese purified solution to prepare a ternary cathode material precursor; The calcination aid is one or both of ammonium chloride and calcium chloride; The carbon reducing agent is 15-30% of the mass of the positive electrode, and the calcination aid is 10-20% of the mass of the positive electrode. The reduction calcination is carried out in two steps: the first step is calcination at 300-350℃ for 0.5-2 hours; the second step is calcination at 700-900℃ for 3-6 hours; the reduction calcination is carried out under an inert atmosphere. The acidic solution is one or more of oxalic acid, citric acid, ascorbic acid, malic acid, and gluconic acid; the concentration of the acidic solution is 0.1-1.5 mol / L.

2. The method for recycling valuable metals from power batteries of new energy vehicles according to claim 1, characterized in that, After the mixture is added to the carbonic acid solution, CO2 is continuously introduced to adjust the pH to 4.0-5.

0.

3. The method for recycling valuable metals from power batteries of new energy vehicles according to claim 1, characterized in that, Step S4 further includes stirring the solution while heating, with the heating temperature being 40-100℃ and the heating time being 1-2 hours.

4. The method for recycling valuable metals from power batteries of new energy vehicles according to claim 1, characterized in that, Step S5 further includes microwave heating or ultrasonic heating, with a heating temperature of 60-100℃ and a heating time of 5-30 minutes.

5. The method for recycling valuable metals from power batteries of new energy vehicles according to claim 1, characterized in that, The method for preparing the ternary cathode material precursor in step S7 is as follows: add one or more of nickel salt, cobalt salt, and manganese salt to the nickel-cobalt-manganese purified solution, add alkaline solution to adjust the pH to 10-13, filter, wash and dry to obtain the nickel-cobalt-manganese ternary precursor material.