Method for recovering manganese and cobalt from waste ternary lithium ion battery by paired electrodeposition

Abstract

The application belongs to the technical field of battery recycling, and particularly relates to a method for recycling manganese and cobalt from waste ternary lithium ion batteries. The method comprises the following steps: using a diaphragm-free electrolysis device, taking a waste lithium ion battery leaching solution as an electrolyte, setting an anode and a cathode, the anode area and the cathode area ratio being related to the initial composition of the electrolyte, and recycling manganese and cobalt through paired electrodeposition. According to the initial concentration of manganese ions and cobalt ions in the electrolyte, the anode area and the cathode area ratio are controlled, manganese and cobalt are recycled through the variable current method, cobalt is recycled at the cathode, manganese dioxide is recycled at the anode, the total current efficiency is greater than 120%, and more than 99% of cobalt and manganese can be recycled through excessive electrolysis. The paired electrodeposition method for recycling cobalt and manganese is developed, cobalt and manganese are recycled by simultaneously using the cathode and the anode electrode reaction, the problem of using organic solvents in the wet method for recycling cobalt and manganese is avoided, wastewater is reduced, and the method has low cost and simple operation.

Description

Technical Field

[0001] This invention belongs to the field of battery recycling technology, specifically relating to a method for recycling manganese and cobalt from waste ternary lithium-ion batteries. Background Technology

[0002] Lithium-ion batteries (LIBs) have become the largest secondary energy storage market due to their high voltage, high energy density, long storage life, wide operating temperature range, and low self-discharge rate. Recently, the increasing popularity of electric vehicles has further driven the rapid expansion of the LIB market demand. With the expansion of the electric vehicle market, electric vehicle battery packs will generate more waste lithium-ion batteries. Therefore, how to efficiently utilize and recycle the valuable metals from waste lithium-ion batteries is of great significance for saving resources, reducing costs, and mitigating environmental pollution in lithium-ion battery production.

[0003] Methods for recycling spent lithium-ion batteries include physical sorting, pyrometallurgical methods, and hydrometallurgical methods. Among these, hydrometallurgical methods are currently the most widely used by companies for recycling valuable metals from spent lithium-ion batteries. This method combines solvent extraction with precipitation. First, the battery casing is leached with acid and alkali solutions. The positive and negative electrode materials are then dissolved in a solution of hydrogen peroxide and sulfuric acid in a specific ratio. Different extractants are then used to selectively extract metals such as copper, manganese, and cobalt, achieving recovery rates of over 96% for each metal. Finally, sodium carbonate is used to separate lithium metal as lithium carbonate precipitate. However, current hydrometallurgical recycling technologies suffer from drawbacks such as the need for large amounts of organic solvents, complex processes, high costs, and the potential for secondary pollution. Electrodeposition can effectively avoid organic solvents and precipitants, significantly reducing pollutant emissions. However, cathode electrodeposition for recovering nickel, cobalt, and manganese suffers from low current efficiency, and the auxiliary electrode undergoes an oxygen evolution reaction, releasing large amounts of oxygen, resulting in underutilization of electrical energy. Furthermore, the oxygen carries acid mist, causing environmental pollution.

[0004] Based on the problems existing in the prior art, this invention proposes to use a paired electrodeposition method to recover cobalt and manganese metals. The cathode and anode simultaneously recover cobalt and manganese from the leachate of waste lithium-ion batteries, which can significantly improve the current efficiency of electrodeposition recovery of cobalt and manganese. Summary of the Invention

[0005] The purpose of this invention is to solve the problems of the prior art and provide a method for recovering manganese and cobalt from waste ternary lithium-ion batteries by paired electrodeposition, which aims to efficiently recover manganese and cobalt from the leachate of waste lithium-ion batteries.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] A method for recovering manganese and cobalt from waste ternary lithium-ion batteries by paired electrodeposition, the method comprising: using a diaphragmless electrolysis device, using leachate from waste lithium-ion batteries as electrolyte, setting up an anode and a cathode, wherein the ratio of the anode area to the cathode area is related to the initial composition of the electrolyte, and recovering manganese and cobalt by paired electrodeposition.

[0008] Preferably, the electrode material of the anode is at least one of graphite, lead alloy, PbO2 / Ti, and IrO2 coated electrode, and more preferably at least one of lead alloy and PbO2 / Ti.

[0009] Preferably, the electrode material of the cathode is at least one of graphite, stainless steel, Ti, and Cu.

[0010] Preferably, the ratio of the anode area to the cathode area is related to the initial composition of the electrolyte, S 阳极 :S 阴极 =2.5*C Mn2+ :C Co2+ C in the electrolyte Co2+ >0.1g / L, C Mn2+ >0.1g / L, C Mn2+ The initial manganese ion content (g / L) of the leachate, C Co2+ The initial cobalt ion content (g / L) of the leachate.

[0011] Preferably, the current density for electrolytic electrodeposition is 300-500 A / m. 2 .

[0012] Preferably, manganese and cobalt are recovered by paired electrodeposition using a variable current method; more preferably, the variable current method is based on Co... 2+ Cathode current density is controlled in stages based on concentration:

[0013] (1)i 阴极 =300-500A / m 2 C Co2+ ≥0.25g / L;

[0014] (2)i 阴极 =200A / m 2 0.1g / L≤C Co2+ <0.25g / L;

[0015] (3)i 阴极 =100A / m 2 C Co2+ <0.1g / L.

[0016] Preferably, the pH of the electrolyte is 0-2. More preferably, the pH of the electrolyte is adjusted to 0-2 using H2SO4 and / or LiOH solution. More preferably, the concentration of H2SO4 is 1 mol / L and the concentration of LiOH solution is 1 mol / L.

[0017] Preferably, the electrolyte temperature is controlled at 20-90℃, more preferably at 50-90℃.

[0018] Preferably, the method for recovering manganese and cobalt by paired electrodeposition according to the present invention can recover most of the cobalt and manganese through excess electrolysis, and can be recovered into the battery leaching solution. Co2+ ≤0.05g / L, C Mn2+ ≤0.05g / L.

[0019] Compared with existing hydrometallurgical methods for recycling cobalt and manganese from waste lithium-ion batteries, the beneficial effects of the technical solution described in this invention are as follows: (1) This invention develops a method for recycling cobalt and manganese by paired electrodeposition, which utilizes both cathode and anode electrode reactions to recover cobalt and manganese; (2) This invention adopts a method for recycling cobalt and manganese by paired electrodeposition with variable current control, which greatly improves the current utilization efficiency; (3) This invention avoids the problem of using organic solvents in the hydrometallurgical recycling of cobalt and manganese, reduces wastewater, and is low in cost and simple to operate. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the electrolysis apparatus of the present invention. In the diagram, 1-anode, 2-cathode

[0021] Figure 2 The images show the XRD patterns of the paired electrodeposited cathode and anode products of this invention. In the images, (a) manganese is recovered from the anode, and (b) cobalt is recovered from the cathode. Detailed Implementation

[0022] The technical solution of the present invention will be further clearly and completely described below through specific embodiments and in conjunction with the accompanying drawings. It should be understood that the embodiments described herein are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures, but are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0023] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, and the materials and reagents used in the examples are commercially available unless otherwise specified.

[0024] This invention provides a method for recovering manganese and cobalt from waste ternary lithium-ion batteries by paired electrodeposition. The method includes: using a diaphragmless electrolysis device, using leachate from waste lithium-ion batteries as electrolyte, setting up an anode and a cathode, wherein the ratio of the anode area to the cathode area is related to the initial composition of the electrolyte, and recovering manganese and cobalt by paired electrodeposition.

[0025] In this invention, the electrode material of the anode is at least one of graphite, lead alloy, PbO2 / Ti, and IrO2 coated electrode, more preferably at least one of lead alloy and PbO2 / Ti.

[0026] In this invention, the electrode material of the cathode is at least one of graphite, stainless steel, Ti, and Cu.

[0027] In this invention, the relationship between the ratio of anode area to cathode area and the initial electrolyte is as follows: S 阳极 :S 阴极 =2.5*C Mn2+ :C Co2+ (C Co2+ >0.1g / L, C Mn2+ >0.1g / L), C Mn2+ The initial manganese ion content (g / L) of the leachate, C Co2+ The initial cobalt ion content (g / L) of the leachate.

[0028] In this invention, the leachate is typically made of sulfuric acid as the leaching solvent to leach used lithium-ion batteries; however, this invention does not limit the leaching solvent, and other solvents can also be used as the leaching solvent.

[0029] In this invention, the pH of the electrolyte is 0-2, more preferably H2SO4 and / or LiOH solution is used to adjust the pH of the electrolyte to 0-2, and more preferably the concentration of H2SO4 is 1 mol / L and the concentration of LiOH solution is 1 mol / L.

[0030] In this invention, the electrolyte temperature is controlled at 20-90°C, more preferably 50-90°C. Controlling the electrolyte temperature at a higher temperature is beneficial for obtaining higher current efficiency.

[0031] In this invention, the current density for electrolytic electrodeposition is 300-500 A / m. 2 By employing constant current electrolysis, high current efficiency and high recovery rate can be obtained.

[0032] In this invention, manganese and cobalt can also be recovered by paired electrodeposition using a variable current method. Electrodeposition using a variable current method achieves better current efficiency and can recover Co and Mn concentrations in the battery leaching solution not exceeding 0.05 g / L. More preferably, the variable current method is used to recover Co...2+ Cathode current density is controlled in stages based on concentration:

[0033] (1)i 阴极 =300-500A / m 2 C Co2+ ≥0.25g / L;

[0034] (2)i 阴极 =200A / m 2 0.1g / L≤C Co2+ <0.25g / L;

[0035] (3)i 阴极 =100A / m 2 C Co2+ <0.1g / L.

[0036] In this invention, the method for recovering manganese and cobalt by paired electrodeposition, through excess electrolysis, can recover most of the cobalt and manganese, which can be recovered into the battery leaching solution. Co2+ ≤0.05g / L, C Mn2+ ≤0.05g / L.

[0037] The technical solution of the present invention will be further illustrated below through specific embodiments. It should be noted that the specific data in the following embodiments are only some embodiments of the present invention, and therefore do not constitute a limitation on the technical solution of the present invention.

[0038] Example 1

[0039] Manganese and cobalt were recovered by electrodeposition using sulfuric acid leaching solution from a waste lithium-ion battery as the electrolyte. The leaching solution composition was 5.2 g / L Ni. 2+ +1.6g / L Co 2+ +2.5g / L Mn 2+ +0.8g / L Li + 2.5C Mn2+ :C Co2+ = 3.9:1; the anion is SO42- 2- Adjust the pH to 1.0 using 1 mol / L LiOH;

[0040] Reference Figure 1 The electrolysis apparatus is configured with an open PTFE rectangular tank (120mm long * 110mm wide * 100mm high) as the electrolysis cell, and cathode 2 is a stainless steel plate (S). 阴 =20cm 2 Anode 1 is a lead alloy (Pb-3.5wt.Sb%, S). 阳 =78cm 2 ), S 阴 :S 阳=1:3.9, electrode spacing is 20mm; placed in electrolyte;

[0041] The electrolyte temperature was adjusted to 80℃ in a constant temperature water bath, and the solution was stirred; the cathode current density was controlled at 400A / m. 2 Constant current electrolysis to C Co2+ Electrolysis ends when the concentration reaches ≤0.25 g / L.

[0042] After electrolysis, the electrodes were removed, the deposits were peeled off, washed with distilled water, and dried at 80°C to constant weight. The mass of the cathode deposit was measured as m1g, and the mass of the anode deposit was measured as m2g. XRD analysis determined the anode product to be γ-MnO2, and ICP-OES analysis showed the γ-MnO2 purity to be 99.46%. The cathode product was metallic Co, with a purity of 99.82%. The current efficiency for Co recovery from cathode electrodeposition was 73.6%, with a recovery rate of 85.4%. The current efficiency for MnO2 recovery from anode electrodeposition was 52.3%, with a recovery rate of 61.2%. The current efficiency was calculated as follows:

[0043]

[0044]

[0045] In the formula:

[0046] m1: Mass of Co (g); M1: Molar mass of Co (g / mol);

[0047] m2: Mass of MnO2 (g); M2: Molar mass of MnO2 (g / mol);

[0048] I: Current (A); t: Electrolysis time (h).

[0049] The results show that high-purity cobalt and manganese dioxide can be obtained by pair electrodeposition, with a total current efficiency exceeding 120%.

[0050] Examples 2-9

[0051] Using the electrode device and leachate from waste lithium-ion batteries from Example 1, different electrode materials were used (while maintaining the same area ratio), and cobalt and manganese were recovered by electrodeposition in pairs using the same method. The experimental results are shown in Table 1.

[0052] Table 1 Current efficiency of paired electrodeposition recovery of cobalt and manganese using different electrode materials

[0053]

[0054] The results in Table 1 show that the selected cathode materials have little impact on the current efficiency of cobalt electrodeposition, with all materials achieving a current efficiency of no less than 60%. The current efficiency of manganese recovery electrodeposition by the anode materials is all above 30%. Among them, lead alloy and lead dioxide electrodes are the better electrode materials, with current efficiencies of no less than 50%. In actual production, appropriate electrode materials can be selected by comprehensively considering factors such as cost.

[0055] Examples 10-17

[0056] The electrode apparatus, electrode materials, and experimental methods of Example 1 were used. Cobalt and manganese were recovered by electrodeposition in pairs using leachates from spent lithium-ion batteries with different compositions and adjusted to different pH values. The experimental results are shown in Table 2.

[0057] Table 2 Current efficiency of paired electrodeposition recovery of cobalt and manganese from leachates with different compositions.

[0058]

[0059] Table 2 shows that the current efficiency of paired electrodeposition of manganese and cobalt remains relatively stable when the pH is maintained between 0 and 2. At pH greater than 3, hydrolysis of metal ions occurs. High concentrations of leachate are beneficial for improving current efficiency and reducing S... 阴 :S 阳 The electrode area ratio and increasing the anode current density are detrimental to manganese recovery, and the increase in anode current density significantly reduces the current efficiency of manganese recovery.

[0060] Example 18

[0061] The electrode device, electrode materials, electrolyte composition, and experimental methods of Example 1 were used. The pH of the solution was adjusted to 1.0, with Co... 2+ Based on concentration changes, cobalt and manganese were recovered by paired electrodeposition using variable current, with the electrolysis endpoint set at C. Mn2+ ≤0.05g / L, and C Co2+ ≤0.05g / L. The experimental results are shown in Table 3.

[0062] Table 3. Current efficiency of paired electrodeposition recovery of cobalt and manganese under variable current control.

[0063]

[0064] The results in Table 3 show that when C Mn2+ ≥2.2g / L, and C Co2+ ≥1.0g / L, controlled at 400A / m 2 Electrolysis at high current density yields cobalt recovery efficiency >70% and manganese recovery efficiency >50%, with increasing Co... 2+ As the concentration decreases, the current density is gradually reduced, and the electrolyte cobalt (Co) 2+At a concentration of 0.1 g / L, the cobalt recovery rate is greater than 90%, and the manganese recovery rate exceeds 50%. When Co... 2+ When the concentration is <0.1 g / L, the anodic current efficiency for manganese recovery increases rapidly and remains at 100 A / m. 2 Excessive current density electrolysis can recover over 99% of cobalt and manganese, with the electrolyte ultimately containing C. Co2+ ≤0.05g / L, C Mn2+ ≤0.05g / L.

[0065] Examples 19-24

[0066] The electrode apparatus, electrode materials, leachate composition, and experimental methods of Example 1 were used. The pH of the solution was adjusted to 1.0, and different electrolyte temperatures were controlled to recover cobalt and manganese through paired electrodeposition. The experimental results are shown in Table 4.

[0067] Table 4. Current efficiency of paired electrodeposition recovery of cobalt and manganese from leachates at different temperatures.

[0068]

[0069]

[0070] The results in Table 4 show that pair electrodeposition in high-concentration cobalt and manganese leaching solutions, along with controlling a higher electrolyte temperature, is beneficial for obtaining higher current efficiency, with a total current efficiency greater than 120%, and for reducing the cell voltage.

[0071] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Other variations and modifications may be made without departing from the technical solutions described in the claims.

Claims

1. A method for recovering manganese and cobalt from waste ternary lithium-ion batteries by paired electrodeposition, characterized in that, The method includes: employing a diaphragm-free electrolysis device, using leachate from spent lithium-ion batteries as the electrolyte, setting up an anode and a cathode, the ratio of anode area to cathode area being related to the initial composition of the electrolyte, and recovering manganese and cobalt through paired electrodeposition; wherein, the relationship between the anode area to cathode area ratio and the initial composition of the electrolyte is, Sanode:Scathode = 2.5 * Cc Mn2+ :C Co2+ C in the electrolyte Co2+ >0.1g / L, C Mn2+ >0.1g / L, of which C Mn2+ C represents the initial manganese ion content of the leachate. Co2+ The initial cobalt ion content of the leachate; the current density for electrolytic electrodeposition is 300-500 A / m. 2 The electrolyte has a pH of 0-2 and a temperature controlled at 20-90℃; the method for recovering manganese and cobalt by paired electrodeposition is used to recover them into the battery leaching solution. Co2+ ≤0.05g / L, C Mn2+ ≤0.05g / L; Manganese and cobalt are recovered by paired electrodeposition using a variable current method, with the variable current method calculated according to Co... 2+ Cathode current density is controlled in stages based on concentration: (1)i 阴极 =300-500A / m 2 ,C Co2+ ≥0.25g / L; (2)i 阴极 =200A / m 2 ,0.1g / L≤C Co2+ <0.25g / L; (3)i 阴极 =100A / m 2 ,C Co2+ <0.1g / L。 2. The method for recovering manganese and cobalt from waste ternary lithium-ion batteries by paired electrodeposition according to claim 1, characterized in that, The electrode material of the anode is at least one of graphite, lead alloy, PbO2 / Ti, and IrO2 coated electrode.

3. The method for recovering manganese and cobalt from waste ternary lithium-ion batteries by paired electrodeposition according to claim 2, characterized in that, The electrode material of the anode is at least one of lead alloy and PbO2 / Ti.

4. The method for recovering manganese and cobalt from waste ternary lithium-ion batteries by paired electrodeposition according to claim 1, characterized in that, The cathode electrode material is at least one of graphite, stainless steel, Ti, and Cu.

5. The method for recovering manganese and cobalt from waste ternary lithium-ion batteries by paired electrodeposition according to claim 1, characterized in that, The electrolyte temperature is controlled at 50-90℃.

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