Method for biologically leaching retired ternary lithium battery positive electrode material under catalysis of silver ions

Abstract

The invention discloses a method for biologically leaching a retired ternary lithium battery positive electrode material under the catalysis of silver ions, which comprises the following steps of: (1) discharging, roasting, disassembling and grinding a retired ternary lithium battery to obtain ternary lithium battery positive electrode material powder; (2), Acidithiobacillus ferrooxidans is inoculated into the culture medium, and when the redox potential in a culture system is larger than or equal to 600 mV, a bacterial culture solution is obtained; and (3) adding the waste ternary lithium battery positive electrode powder into a bacterial culture solution, then adding a silver nitrate solution for leaching, and culturing for 3-7 days to obtain a biological leaching solution. According to the method, the biological leaching rate of metal is increased through silver ions, operation is easy and convenient to implement, the catalyst is simple and easy to obtain, the production cost is low, and environmental pollution is small, and the method has good application prospects.

Description

Technical Field

[0001] The present invention belongs to the field of resource recycling and mainly relates to a method for bioleaching of retired ternary lithium battery positive electrode materials using silver ions as catalysts. Background Art

[0002] Against the backdrop of the rapid rise of new energy vehicles and energy storage materials, the output of lithium-ion batteries has seen explosive growth. x Co y Mn z O2 boasts advantages such as high energy density and long cycle life, making it the current mainstream long-range power battery. With the rapid increase in the number of new energy vehicles, the number of retired power batteries is also increasing year by year. If these batteries are not properly handled, not only will valuable metal resources be lost, but they may also cause serious public health and environmental safety issues. The development of efficient clean recycling technologies for waste ternary lithium battery cathode materials will not only promote the recycling of limited resources and expand the supply of scarce resources, but also effectively avoid the potential risks posed by waste materials to human health and the ecological environment, thereby generating multiple positive effects in terms of resource conservation, improved economic efficiency, and enhanced social welfare.

[0003] Bioleaching is one of the technologies with great development potential in the field of recycling waste lithium battery positive electrode materials due to its advantages such as low cost, green environmental protection and simple process. However, the slow leaching rate and long leaching cycle lead to slow metal dissolution kinetics, which is one of the important factors limiting the large-scale promotion and application of traditional bioleaching technology in the recycling industry of waste ternary lithium battery positive electrode materials. In order to improve the bioleaching kinetics and shorten the reaction cycle, domestic and foreign scholars have explored various methods to accelerate bioleaching, among which the method of adding metal ions as catalysts has attracted much attention. The research team of Professor Luo Shenglian of Hunan University found that using Cu 2+ As a catalyst, Thiobacillus ferrooxidans was used to bioleach Co in spent lithium battery LiCoO2. 0.75 g / L Cu was added to the leaching system. 2+ After that, the leaching time was shortened from 10 days to 6 days, and the leaching rate of Co was increased from 43.1% to 99.9%. + It also has a solubilizing effect on Co and Ni in waste lithium batteries. Noruzi et al. gradually increased the proportion of waste lithium batteries in the leaching system and used Ag + The two-step bioleaching method under catalysis can finally achieve a Co and Ni extraction rate of 99.95% within 3 days. The addition of metal ions can react with Li in the waste lithium battery positive electrode material. + A cation exchange reaction occurs to generate Fe 3+Intermediate products of reduction and dissolution. Therefore, strategies such as adding metal ion catalysts can effectively improve metal recovery and shorten the reaction cycle. However, current research on metal ion-catalyzed bioleaching of spent lithium batteries primarily focuses on the recovery of lithium cobalt oxide, while research on the more complex cathode materials of ternary lithium batteries is rare.

[0004] In summary, the method of the present invention is proposed: silver ions are added as a catalyst in the bioleaching system of Thiobacillus ferrooxidans to efficiently leach valuable metals in waste ternary lithium battery positive electrode materials in a short time. Summary of the Invention

[0005] The present invention aims to solve the problem of recycling the positive electrode materials of retired ternary lithium batteries and provides a method for bioleaching the positive electrode materials of retired ternary lithium batteries by catalyzing silver ions.

[0006] The method for bioleaching of retired ternary lithium battery cathode materials catalyzed by silver ions of the present invention comprises the following steps: 1. Pretreatment of waste ternary lithium battery materials Discharging, calcining and disassembling waste ternary lithium batteries to obtain ternary lithium positive electrode material powder; 2. Cultivation of microorganisms Acidithiobacillus ferrooxidans is inoculated into the culture medium, and the culture is placed in a constant temperature shaking incubator at a temperature of 28-32°C and a rotation speed of 150-200 rpm. When the redox potential in the culture system reaches ≥600 mV, a bacterial culture solution is obtained. 3. Bioleaching The waste ternary lithium battery positive electrode powder obtained by pretreatment is added to the bacterial culture solution, and then a silver nitrate solution is added for leaching. The culture is carried out for 3-7 days at a temperature of 28-32°C and a rotation speed of 150-200 rpm to obtain a biological leaching solution.

[0007] Furthermore, the 9K culture medium consists of 3 g / L (NH4)2SO4, 0.5 g / L KCl, 0.1 g / L K2HPO4, 0.5 g / L MgSO4·7H2O, 0.01 g / L Ca(NO3)2 and 44.2 g / L green vitriol, and the pH is adjusted to 1.8-2.0 with sulfuric acid.

[0008] Furthermore, the inoculation amount of the Thiobacillus ferrooxidans is 5-10% V / V.

[0009] Furthermore, the addition amount of the ternary lithium battery positive electrode material powder is 2-10% W / V.

[0010] Furthermore, the amount of the silver nitrate solution added is 2-10 mmol / L based on the concentration of silver ions in the leachate.

[0011] Furthermore, the mass percentages of lithium, nickel, cobalt and manganese in the retired ternary lithium battery positive electrode material are 6.8~7.4%, 28.2~29.8%, 10.25~12.89% and 15.5~16.7%, respectively.

[0012] In the present invention, the concentration of metal ions is measured by performing inductively coupled plasma optical emission spectroscopy (ICP-OES) on the finally obtained bioleaching solution to obtain the leaching rate of the metal elements.

[0013] The present invention has the beneficial effects of adding a small amount of silver ions as a catalyst during the leaching of the positive electrode active material of waste ternary lithium batteries, thereby improving the metal leaching rate. The leaching rates of lithium, nickel, cobalt, and manganese reached 99.9%, 62.46%, 60.74%, and 58.28%, respectively. Compared with the case without the addition of silver ions, the leaching rates of lithium, nickel, cobalt, and manganese increased by 30%, 82%, 126%, and 103%, respectively, demonstrating a significant catalytic effect. The method of the present invention has the advantages of high leaching rate, low reagent consumption, low production cost, low environmental pollution, and simple operation, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0015] Figure 1 Process flow for bioleaching of retired ternary lithium battery cathode materials catalyzed by silver ions Figure 2 XRD patterns before and after silver ion catalysis of spent ternary lithium battery bioleaching DETAILED DESCRIPTION

[0016] The present invention is described in detail below with reference to the embodiments, but the protection scope of the present invention is not limited to the following embodiments.

[0017] Example 1 (1) After discharging, roasting, disassembling and grinding, the positive electrode material powder of the ternary lithium battery can be obtained; (2) Add 44.2 g / L green vitriol and 95 mL of 9K medium to a 250 mL conical flask, add 5 mL of Acidithiobacillus ferrooxidans, and culture in a constant temperature shaking incubator at 30°C and 170 rpm. When the redox potential in the culture system is ≥600 mV, the bacterial culture solution can be obtained.

[0018] (3) Add 1 g of spent ternary lithium battery cathode material powder to the bacterial culture medium obtained in step (2), then add 10 mmol / L silver ions for bioleaching, and incubate for 3-7 days. Samples are taken regularly every day, filtered with a water filter (0.22 μm), and the concentrations of lithium, nickel, cobalt, and manganese in the leachate are measured using inductively coupled plasma optical emission spectroscopy (ICP-OES) and the extraction percentage is calculated.

[0019] The results showed that after 7 days of bioleaching, the leaching rate of lithium reached 95.9%, the leaching rate of nickel reached 40.7%, the leaching rate of cobalt reached 29.3%, and the leaching rate of manganese reached 30.3%.

[0020] Example 2 (1) After discharging, roasting, disassembling and grinding, the positive electrode material powder of the ternary lithium battery can be obtained; (2) Add 44.2 g / L green vitriol and 92 mL of 9K medium to a 250 mL conical flask, add 8 mL of Acidithiobacillus ferrooxidans, and culture in a constant temperature shaking incubator at 30°C and 170 rpm. When the redox potential in the culture system is ≥600 mV, the bacterial culture solution can be obtained.

[0021] (3) Add 0.4 g of spent ternary lithium battery cathode material powder to the bacterial culture medium obtained in step (2), then add 6 mmol / L of silver ions for bioleaching, and incubate for 3-7 days. Samples are taken regularly every day, filtered with a water filter (0.22 μm), and the concentrations of lithium, nickel, cobalt, and manganese in the leachate are measured using inductively coupled plasma optical emission spectroscopy (ICP-OES) and the extraction percentage is calculated.

[0022] The results showed that after 7 days of bioleaching, the leaching rate of lithium reached 98.9%, the leaching rate of nickel reached 45.3%, the leaching rate of cobalt reached 51.7%, and the leaching rate of manganese reached 52.1%.

[0023] Example 3 A Cu 2+ The method for catalyzing bioleaching of retired ternary lithium battery cathode materials comprises the following steps: (1) After discharging, roasting, disassembling and grinding, the positive electrode material powder of the ternary lithium battery can be obtained; (2) Add 44.2 g / L green vitriol and 92 mL of 9K medium to a 250 mL Erlenmeyer flask, add 10 mL of Acidithiobacillus ferrooxidans, and culture in a constant temperature shaking incubator at 30 °C and 170 rpm. When the redox potential in the culture system is ≥600 mV, the bacterial culture solution can be obtained.

[0024] (3) Add 0.2 g of spent ternary lithium battery cathode material powder to the bacterial culture medium obtained in step (2), then add 2 mmol / L silver ions for bioleaching, and incubate for 3-7 days. Samples are taken regularly every day, filtered with a water filter (0.22 μm), and the concentrations of lithium, nickel, cobalt, and manganese in the leachate are measured using inductively coupled plasma optical emission spectroscopy (ICP-OES) and the extraction percentage is calculated.

[0025] The results showed that after 7 days of bioleaching, the leaching rate of lithium reached 99.9%, the leaching rate of nickel reached 62.46%, the leaching rate of cobalt reached 60.74%, and the leaching rate of manganese reached 58.28%. This shows that the method of the present invention can effectively improve the bioleaching rate. Using the method of the present invention to bioleach waste ternary lithium-ion battery positive electrode materials can significantly improve the bioleaching rate of metal ions.

Claims

1. A method for bioleaching of retired ternary lithium battery cathode materials catalyzed by silver ions, characterized in that: Silver ions are used as catalyst.

2. A method for bioleaching of retired ternary lithium battery cathode materials catalyzed by silver ions, characterized in that: Proceed as follows: Step 1: Discharge, calcine and disassemble the waste ternary lithium battery to obtain ternary lithium positive electrode material powder; Step 2: Acidithiobacillus ferrooxidans is inoculated into the culture medium and cultured in a constant temperature shaking incubator at a temperature of 28-32°C and a rotation speed of 150-200 rpm. When the redox potential in the culture system reaches ≥600 mV, a bacterial culture solution is obtained. Step 3: Add the spent ternary lithium battery positive electrode powder to the bacterial culture medium, then add silver nitrate solution for leaching, and culture for 3-7 days to obtain a biological leaching solution.

3. The method for bioleaching of retired ternary lithium battery cathode materials catalyzed by silver ions according to claim 2, characterized in that The culture medium in step 2 is 9K culture medium, which consists of 3 g / L (NH4)2SO4, 0.5 g / L KCl, 0.1 g / L K2HPO4, 0.5 g / L MgSO4·7H2O, 0.01 g / L Ca(NO3)2 and 44.2 g / L green vitriol, and the pH is adjusted to 1.8~2.0 with sulfuric acid.

4. The method for bioleaching of retired ternary lithium battery cathode materials catalyzed by silver ions according to claim 2, characterized in that The inoculation amount of Thiobacillus ferrooxidans in step 2 is 5-10% V / V.

5. The method for bioleaching of retired ternary lithium battery cathode materials catalyzed by silver ions according to claim 2, characterized in that The addition amount of the ternary lithium battery positive electrode material powder in step 3 is 2~10% W / V.

6. The method for bioleaching of retired ternary lithium battery cathode materials catalyzed by silver ions according to claim 2, characterized in that The amount of silver nitrate solution added in step 3 is based on the concentration of silver ions in the leachate being 2 to 10 mmol / L.

7. The method for bioleaching of retired ternary lithium battery cathode materials catalyzed by silver ions according to claim 2, characterized in that: The mass percentages of lithium, nickel, cobalt and manganese in the retired ternary lithium battery positive electrode material are 6.8~7.4%, 28.2~29.8%, 10.25~12.89% and 15.5~16.7%, respectively.

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