A method for recovering nickel from waste ternary lithium batteries

Abstract

A method for recovering nickel from spent ternary lithium batteries includes the following steps: discharging and disassembling the spent batteries to separate the positive electrode; grinding the positive electrode, adding a carbon reducing agent and mixing thoroughly to obtain mixed positive electrode powder, then reducing and calcining the mixed positive electrode powder to obtain reduced battery powder; and adding the reduced battery powder to NH4. + -S 2‑ The reaction is carried out in a solution, and after filtration, a leachate and a leachate residue are obtained. The leachate is heated while an alkaline solution is added to adjust the pH, and then filtered to obtain nickel hydroxide. This invention utilizes nickel, cobalt, manganese, and lithium ions in NH4+. + -S 2‑ The difference in complexation in the system solution allows nickel and cobalt ions to be separated from it. Then, through deammoniation and pH adjustment, the nickel ions are precipitated as nickel hydroxide. Compared with traditional recycling processes, this avoids the use of strong acid leaching and extraction. The reaction conditions are milder and the process is simpler, which can reduce the requirements for equipment and thus reduce production costs.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery recycling, and more particularly to a method for recovering nickel from waste ternary lithium batteries. Background Technology

[0002] Lithium-ion batteries are a core component of new energy vehicles, and with the rapid development of new energy vehicles, the number of lithium-ion batteries in use has increased rapidly. At the same time, the recycling of used lithium-ion batteries has received widespread attention, especially the recycling of used ternary lithium-ion batteries, which has propelled the resource utilization of used ternary lithium-ion batteries into a fast track of development.

[0003] Nickel is used extensively in ternary lithium-ion batteries because of its relatively low price. In industry, nickel is usually extracted and separated to recover it. However, the disadvantages of extraction and separation are that the extractant is expensive, and a large amount of wastewater is generated after extraction. The process is complex and costly. Summary of the Invention

[0004] Therefore, the purpose of this invention is to provide a simple and efficient method for recycling nickel from waste ternary lithium batteries.

[0005] A method for recovering nickel from spent ternary lithium batteries includes the following steps:

[0006] Discharge and disassemble used batteries to separate the positive electrode;

[0007] The positive electrode is ground, and a carbon reducing agent is added and mixed thoroughly to obtain mixed positive electrode powder. The mixed positive electrode powder is then reduced and calcined to obtain reduced battery powder.

[0008] The reduced battery powder was added to NH4 + -S 2- The reaction occurs in the system solution, and after filtration, leachate and leachate residue are obtained.

[0009] The leachate was heated while an alkaline solution was added to adjust the pH, and then filtered to obtain nickel hydroxide.

[0010] This invention involves discharging and dismantling spent ternary lithium batteries to separate the positive electrode; the positive electrode is then mixed with a carbon reducing agent and subjected to reduction calcination to obtain reduced battery powder containing lithium carbonate, nickel carbonate, manganese carbonate, and cobalt carbonate; the reduced battery powder is then added to NH4. + -S 2- In the solution of this system, nickel-cobalt ions react with NH4+. + Forming a complex, dissolving in solution, manganese ions react with S 2- The reaction forms a precipitate in which lithium carbonate is insoluble. After filtration and separation, the main component of the leachate is NH4 containing nickel and cobalt ions. +-S 2- The system solution; heating the leachate can release NH4 + -S 2- NH4 in the system solution + It is released as NH3, and the pH of the solution is adjusted to cause nickel to precipitate as nickel hydroxide.

[0011] As a preferred embodiment, the NH4 + -S 2- The system solution is at least one of ammonium sulfide solution and hydrogen sulfide ammonia solution. Ammonium sulfide solution and hydrogen sulfide ammonia solution do not introduce other components, which facilitates subsequent separation.

[0012] As a preferred embodiment, the NH4 + -S 2- The system solution temperature is 0-30℃, and the reaction time is 4-12h. Reacting at room temperature can reduce energy consumption and avoid NH4+. + -S 2- The system solution evaporates.

[0013] As a preferred embodiment, the NH4 + -S 2- In the system solution, NH4 + The concentration is 1-5 mol / L, high concentration of NH4 + This helps to dissolve nickel ions as much as possible in the solution, thereby improving the recovery rate of nickel ions.

[0014] As a preferred embodiment, the reduced battery powder and the NH4 + -S 2- The mass ratio of the system solution is 1:5-1:30. If the mass ratio is too low, the leaching time is long and the manganese ions are not completely precipitated. If the mass ratio is too high, more waste liquid will be generated.

[0015] As a preferred embodiment, the alkaline solution is a sodium hydroxide solution, which is a common alkaline solution that is readily available and does not cause sodium ions to precipitate.

[0016] As a preferred option, adding an alkaline solution to adjust the pH to 7.5-10.0 can precipitate as many nickel ions as possible, thereby improving the nickel recovery rate, while avoiding the precipitation of cobalt.

[0017] As a preferred embodiment, the mass of the carbon reducing agent is 15-30% 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 and the nickel recovery rate will be low. If the mass ratio is too high, it will not significantly improve the nickel recovery rate and will increase the cost.

[0018] As a preferred embodiment, the reduction roasting temperature is 500-700℃ and the time is 3-8h. The reduction roasting is carried out under an inert atmosphere. At this time and temperature, the carbon reducing agent can destroy the positive electrode structure and reduce the lithium, nickel, cobalt and manganese therein. The inert atmosphere avoids oxidation during the roasting process and ensures that the reduction roasting achieves the expected effect.

[0019] As a preferred embodiment, the leaching solution is heated to a temperature of 40-100℃ for 1-3 hours. If the temperature is too low, the NH3 removal rate will be too low, and if the temperature is too high, the NH3 removal rate will not increase significantly.

[0020] This invention utilizes nickel, cobalt, manganese, and lithium ions in NH4 + -S 2- The difference in complexation in the system solution separates nickel and cobalt ions, which are then precipitated as nickel hydroxide by deammoniation and pH adjustment. Compared with traditional recycling processes, the method for recovering nickel from spent ternary lithium batteries described in this invention avoids the use of strong acid leaching and extraction, employs milder reaction conditions, and has a simpler process, reducing equipment requirements and thus lowering production costs. Detailed Implementation

[0021] The present invention discloses a method for recovering nickel from spent ternary lithium batteries, comprising the following steps:

[0022] Discharge and disassemble used batteries to separate the positive electrode;

[0023] The positive electrode is ground, and a carbon reducing agent is added and mixed thoroughly to obtain a mixed positive electrode powder. The mass of the carbon reducing agent is 15-30% of the mass of the positive electrode. Subsequently, the mixed positive electrode powder is reduced and calcined under an inert atmosphere at a temperature of 500-700°C for 3-8 hours to obtain reduced battery powder.

[0024] The reduced battery powder was added to NH4 + -S 2- The reaction occurs in the system solution, where the reduced battery powder reacts with the NH4. + -S 2- The mass ratio of the system solution is 1:10-1:30. The reaction is carried out at 0-30℃ for 4-12 hours. After filtration, leachate and leachate residue are obtained.

[0025] The leachate is heated to 40-100℃ for 1-3 hours, while sodium hydroxide is added to adjust the pH to 7.5-10.0. The solution is then filtered to obtain nickel hydroxide.

[0026] Example 1

[0027] A method for recovering nickel from spent ternary lithium batteries includes the following steps:

[0028] Discharge and disassemble used batteries to separate the positive electrode;

[0029] The positive electrode is ground, and a carbon reducing agent is added and mixed thoroughly to obtain a mixed positive electrode powder. The mass of the carbon reducing agent is 15% of the mass of the positive electrode. Subsequently, the mixed positive electrode powder is reduced and calcined under an inert atmosphere at a temperature of 500°C for 8 hours to obtain reduced battery powder.

[0030] Configure NH4 + A 2 mol / L ammonium sulfide solution was prepared, and the reduced battery powder was added to the ammonium sulfide solution. The mass ratio of the reduced battery powder to the ammonium sulfide solution was 1:15. The reaction was carried out at 0°C for 12 hours, and the leachate and leachate residue were obtained after filtration.

[0031] The leachate was heated to 60°C for 1.5 hours, while sodium hydroxide was added to adjust the pH to 8.5. The solution was then filtered to obtain nickel hydroxide.

[0032] The nickel ion recovery rate in the obtained nickel hydroxide was 95.1%.

[0033] Example 2

[0034] A method for recovering nickel from spent ternary lithium batteries includes the following steps:

[0035] Discharge and disassemble used batteries to separate the positive electrode;

[0036] The positive electrode is ground, and a carbon reducing agent is added and mixed thoroughly to obtain a mixed positive electrode powder. The mass of the carbon reducing agent is 30% of the mass of the positive electrode. Subsequently, the mixed positive electrode powder is reduced and calcined under an inert atmosphere at a temperature of 700°C for 3 hours to obtain reduced battery powder.

[0037] Configure NH4 + A 5 mol / L ammonium sulfide solution was prepared, and the reduced battery powder was added to the ammonium sulfide solution. The mass ratio of the reduced battery powder to the ammonium sulfide solution was 1:5. The reaction was carried out at 10°C for 8 hours. After filtration, leachate and leachate residue were obtained.

[0038] The leachate was heated to 40°C for 3 hours, while sodium hydroxide was added to adjust the pH to 7.5. The solution was then filtered to obtain nickel hydroxide.

[0039] The nickel ion recovery rate in the obtained nickel hydroxide was 95.5%.

[0040] Example 3

[0041] A method for recovering nickel from spent ternary lithium batteries includes the following steps:

[0042] Discharge and disassemble used batteries to separate the positive electrode;

[0043] The positive electrode is ground, and a carbon reducing agent is added and mixed thoroughly to obtain a mixed positive electrode powder. The mass of the carbon reducing agent is 20% of the mass of the positive electrode. Subsequently, the mixed positive electrode powder is reduced and calcined under an inert atmosphere at a temperature of 600°C for 4 hours to obtain reduced battery powder.

[0044] Configure NH4 + An ammonium sulfide solution with a concentration of 3 mol / L was prepared. The reduced battery powder was added to the ammonium sulfide solution, and the mass ratio of the reduced battery powder to the ammonium sulfide solution was 1:20. The reaction was carried out at 20°C for 6 hours. After filtration, leachate and leachate residue were obtained.

[0045] The leachate was heated to 80°C for 1 hour, while sodium hydroxide was added to adjust the pH to 9.0. The solution was then filtered to obtain nickel hydroxide.

[0046] The nickel ion recovery rate in the obtained nickel hydroxide was 96.9%.

[0047] Example 4

[0048] A method for recovering nickel from spent ternary lithium batteries includes the following steps:

[0049] Discharge and disassemble used batteries to separate the positive electrode;

[0050] The positive electrode is ground, and a carbon reducing agent is added and mixed thoroughly to obtain a mixed positive electrode powder. The mass of the carbon reducing agent is 25% of the mass of the positive electrode. Subsequently, the mixed positive electrode powder is reduced and calcined under an inert atmosphere at a temperature of 550°C for 5 hours to obtain reduced battery powder.

[0051] Configure NH4 + An ammonium sulfide solution with a concentration of 1 mol / L was prepared. The reduced battery powder was added to the ammonium sulfide solution, and the mass ratio of the reduced battery powder to the ammonium sulfide solution was 1:30. The reaction was carried out at 25°C for 4 hours. After filtration, leachate and leachate residue were obtained.

[0052] The leachate was heated to 100°C for 1 hour, while sodium hydroxide was added to adjust the pH to 10.0. The solution was then filtered to obtain nickel hydroxide.

[0053] The nickel ion recovery rate in the obtained nickel hydroxide was 96.3%.

[0054] Example 5

[0055] A method for recovering nickel from spent ternary lithium batteries includes the following steps:

[0056] Discharge and disassemble used batteries to separate the positive electrode;

[0057] The positive electrode is ground, and a carbon reducing agent is added and mixed thoroughly to obtain a mixed positive electrode powder. The mass of the carbon reducing agent is 25% of the mass of the positive electrode. Subsequently, the mixed positive electrode powder is reduced and calcined under an inert atmosphere at a temperature of 550°C for 5 hours to obtain reduced battery powder.

[0058] Configure NH4 + A 2 mol / L ammonium hydrogen sulfide solution was prepared, and the reduced battery powder was added to the ammonium sulfide solution. The mass ratio of the reduced battery powder to the ammonium sulfide solution was 1:25. The reaction was carried out at 30°C for 6 hours, and the leachate and leachate residue were obtained after filtration.

[0059] The leachate was heated to 80°C for 1 hour, while sodium hydroxide was added to adjust the pH to 9.5. The solution was then filtered to obtain nickel hydroxide.

[0060] The nickel ion recovery rate in the obtained nickel hydroxide was 96.2%.

[0061] The embodiments described above are merely examples 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 recovering nickel from spent ternary lithium batteries, characterized in that, Includes the following steps: Discharge and disassemble used batteries to separate the positive electrode; The positive electrode is ground, and a carbon reducing agent is added and mixed thoroughly to obtain mixed positive electrode powder. The mixed positive electrode powder is then reduced and calcined to obtain reduced battery powder. The reduced battery powder was added to NH 4+ -S 2- The system is in solution and reacted at 0-30℃. After filtration, leachate and leachate residue are obtained. The leachate is heated to 40-100°C, and an alkaline solution is added to adjust the pH to 7.5-10.

0. The solution is then filtered to obtain nickel hydroxide. The NH 4+ -S 2- The system solution is at least one of ammonium sulfide solution and hydrogen sulfide ammonia solution; The NH 4+ -S 2- In the system solution, NH 4+ The concentration is 1-5 mol / L; The reduced battery powder and the NH 4+ -S 2- The mass ratio of the solutions in the system is 1:5 to 1:

30.

2. The method for recovering nickel from spent ternary lithium batteries according to claim 1, characterized in that, The reduced battery powder is added to the NH 4+ -S 2- After the system is dissolved, the reaction time is 4-12 hours.

3. The method for recovering nickel from spent ternary lithium batteries according to claim 1, characterized in that, The alkaline solution is a sodium hydroxide solution.

4. The method for recovering nickel from spent ternary lithium batteries according to claim 1, characterized in that, The mass of the carbon reducing agent is 15-30% of the mass of the cathode.

5. The method for recovering nickel from spent ternary lithium batteries according to claim 1, characterized in that, The reduction calcination temperature is 500-700℃, and the time is 3-8 hours. The reduction calcination is carried out under an inert atmosphere.

6. The method for recovering nickel from spent ternary lithium batteries according to claim 1, characterized in that, The leaching solution is heated for 1-3 hours.