Method for selectively extracting lithium from waste ternary lithium ion battery positive electrode material through ball milling

Abstract

The invention relates to the technical field of resource recycling and reusing, in particular to a method for selectively extracting lithium from a waste ternary lithium ion battery positive electrode material through ball milling. The invention discloses a method which comprises the following steps: mixing a waste ternary lithium ion battery positive electrode material with brominated epoxy resin, and then carrying out ball milling treatment on the mixture and a ball milling agent under the protection of nitrogen to obtain primary ball-milled powder; and then, carrying out secondary ball milling on the primary ball-milled powder to obtain secondary ball-milled powder, and finally, carrying out acid leaching treatment to realize selective extraction of lithium. According to the embodiment, the method can effectively solve the problems of high lithium loss, low lithium leaching rate and poor lithium selectivity in the traditional waste lithium battery recovery method. In addition, the method is simple and convenient to operate, and valuable metal lithium in the waste ternary lithium ion battery positive electrode material can be selectively recycled.

Description

Technical Field

[0001] The invention belongs to the technical field of waste lithium battery resource recovery and reuse, and in particular relates to a method for selectively extracting lithium from waste ternary lithium-ion batteries. Background Art

[0002] With the booming development of the electronics industry, the demand for lithium continues to rise. Lithium-ion batteries have been widely used in the electronics industry due to their excellent charge and discharge efficiency and high energy density. However, while the prosperity of the electronics industry has promoted economic growth, it has also caused a series of problems. In particular, the limited service life of lithium-ion batteries has led to a sharp increase in the number of waste batteries, among which waste ternary lithium-ion batteries account for a large proportion, which not only accelerates the consumption of natural resources such as lithium, nickel, cobalt, and manganese, but also urgently needs to be recycled due to the high-value metals contained in waste batteries to improve the recycling rate of resources. In addition, the toxic and harmful substances contained in the battery pose a potential threat to soil and water sources. Therefore, efficient and environmentally friendly resource recovery technology for waste ternary lithium-ion batteries is particularly important and of great practical value.

[0003] At present, the technologies for recycling waste ternary lithium-ion batteries mainly include pyrometallurgy, hydrometallurgy and direct recycling and regeneration. Hydrometallurgy has problems such as long process, difficulty in separating multiple metals, lithium loss in the recycling process, and generation of a large amount of wastewater. At the same time, pyrometallurgy also has problems such as high energy consumption, low metal recovery rate, low metal recovery purity and toxic waste gas emissions. Therefore, developing an efficient and environmentally friendly method to selectively extract lithium from waste ternary lithium-ion battery cathode materials has obvious economic value and social benefits. Summary of the invention

[0004] The present invention provides a method for selectively extracting lithium by ball milling of waste ternary lithium-ion battery positive electrode materials. The method is to selectively extract lithium by ball milling. During the ball milling process, the brominated epoxy resin is decomposed into hydrogen bromide, small molecular hydrocarbons and carbon under the action of mechanochemical force. The generated hydrogen bromide undergoes a bromination reaction with the waste ternary lithium-ion battery positive electrode materials, and the generated small molecular hydrocarbons can undergo a reduction reaction with the waste ternary lithium-ion battery positive electrode materials, thereby realizing the selective extraction of lithium. The method has the advantages of low energy consumption, low pollution and high selectivity.

[0005] In order to achieve the above-mentioned object, the present invention proposes a method for selectively extracting lithium by ball milling of waste ternary lithium-ion battery positive electrode materials, and the specific steps are as follows: (1) ball milling the waste ternary lithium-ion battery positive electrode materials, brominated epoxy resin and ball milling agent under inert gas protection according to primary ball milling parameters to obtain primary ball milled powder; (2) performing secondary ball milling treatment on the primary ball milled powder obtained in step (1) according to secondary ball milling parameters to obtain secondary ball milled powder; (3) acid leaching the secondary ball milled powder obtained in step (2).

[0006] In the step (1), the waste ternary lithium-ion battery is NCM111, or NCM523, or NCM622, or NCM811, or a mixture of the above batteries.

[0007] The brominated epoxy resin in step (1) is uncured or cured brominated epoxy resin, and mixed plastics rich in brominated epoxy resin.

[0008] The ball milling agent in step (1) is SiO 2 , or Na 2 S 2 O 3 , or K 2 S 2 O 3 , or a mixture of the three.

[0009] In the step (1), the mass ratio of the waste ternary lithium-ion battery: brominated epoxy resin: ball mill is 1: (0.5-3): (1-5).

[0010] In the ball milling process in step (1) of the present invention, the inert gas is nitrogen, argon, helium, or a mixture of nitrogen, argon and helium in any volume ratio.

[0011] The parameters of the first ball milling in step (1) are as follows: the mass ratio of the first ball milling ball to the material is (20-50): 1, the first ball milling speed is 900-1400 rpm, the first ball milling time is 0.5-3 h, the first ball milling pressure is 0.01-0.05 MPa, and the first ball milling temperature is 20-60° C.

[0012] The secondary ball milling parameters in step (2) are: secondary ball milling ball to material mass ratio (30-50):1, secondary ball milling speed is 1100-1600 rpm, secondary ball milling time is 1-5 h, secondary ball milling pressure is 0.01-0.1 MPa, and secondary ball milling temperature is 40-70 °C.

[0013] The acid used for acid leaching in step (3) is dilute sulfuric acid, dilute nitric acid, dilute hydrochloric acid, or a mixture of dilute sulfuric acid, dilute nitric acid and dilute hydrochloric acid in any mass ratio, and the pH value is 4-6.

[0014] In the step (3), the solid-liquid ratio of the acid leaching is 50-200 g / L, the leaching time is 1-3 h, the leaching temperature is 40-70° C., and the stirring speed is 100-300 rpm.

[0015] The present invention provides a method for selectively extracting lithium from the cathode material of waste ternary lithium-ion batteries by ball milling. This method makes the cathode material of waste ternary lithium-ion batteries react with brominated epoxy resin by applying mechanochemical force, and adds an abrasive to increase the reaction contact area, thereby providing more reactive sites. During the grinding process, the C-Br bond of brominated epoxy resin breaks, forming a small amount of hydrogen bromide, reducing hydrocarbons, benzene, phenol homologues, etc. Hydrogen bromide reacts with the oxygen in the waste ternary lithium-ion battery, and the structural oxygen is destroyed, forming many unstable oxygen vacancies. Then, secondary ball milling is carried out, and the structural oxygen is further destroyed. Co, Mn, and Ni form CoO, MnO, and NiO, and Li forms soluble oxide Li 2 O. By acid leaching Li 2 in O, Li + is released into the aqueous solution to achieve selective extraction of lithium. The results of experimental examples show that the method for recovering lithium provided by the present invention can make the leaching rate of lithium reach more than 95% and the purity is high.

[0016] Compared with the prior art, the present invention has the advantages of simple operation, low energy consumption, environmental friendliness, high selectivity, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is the XRD pattern of the cathode material of the waste ternary lithium-ion battery involved in the present invention.

[0018] Figure 2 It is a schematic diagram of the test results of the lithium leaching rate under the condition of primary ball milling involved in the present invention. The black line represents the mass ratio of waste ternary lithium-ion battery: brominated epoxy resin: abrasive 1:1:2, the blue line represents the mass ratio of waste ternary lithium-ion battery: abrasive 1:2, and the red line represents the mass ratio of waste ternary lithium-ion battery: brominated epoxy resin 1:1.

[0019] Figure 3 It is a schematic diagram of the test results of the lithium leaching rate under the condition of secondary ball milling involved in the present invention. The black line represents the mass ratio of waste ternary lithium-ion battery: brominated epoxy resin: abrasive 1:1:2, the blue line represents the mass ratio of waste ternary lithium-ion battery: abrasive 1:2, and the red line represents the mass ratio of waste ternary lithium-ion battery: brominated epoxy resin 1:1. DETAILED DESCRIPTION OF THE INVENTION

[0020] The technical solution of the present invention will be described in detail below through specific embodiments.

[0021] Example 1: This example is a method for selectively extracting lithium from the cathode material of waste ternary lithium-ion batteries by ball milling, including the following steps: (1) Grind and mix the cathode material of waste NCM111 battery and brominated epoxy resin according to a mass ratio of 1:1 to obtain a mixed powder. (2) Mix the above mixed powder with the ball milling agent Na 2S 2 O 3 According to the mass ratio of 1:2, it is added into the ball mill and ball milled under nitrogen protection. The parameters of the first ball milling are: the mass ratio of ball to material is 30:1, the rotation speed is 900rpm, the time is 2h, the pressure is 0.05Mpa, and the temperature is 50℃. The parameters adopted are not under the optimal conditions. The grinding balls are zirconium dioxide balls, and the first ball milling powder is obtained. (3) After obtaining the first ball milling powder, the first ball milling powder is subjected to a second ball milling. The ball to material ratio of the second ball milling is preferably 30:1, the rotation speed is preferably 1400rpm; the time is preferably 2h; the pressure is preferably 0.04Mpa; the temperature is preferably 60℃, and the second ball milling powder is obtained. (4) After obtaining the second ball milling powder, the second ball milling powder is subjected to the dilute sulfuric acid water with pH=4 to extract lithium, and the leaching rate reaches 96.11%.

[0022] Example 2: This example is a method for selectively extracting lithium from waste ternary lithium-ion battery positive electrode materials by ball milling, comprising the following steps: (1) grinding and mixing waste NCM111 battery positive electrode materials and brominated epoxy resin in a mass ratio of 1:1 to obtain a mixed powder. (2) mixing the mixed powder with a ball milling agent Na 2 S 2 O 3 According to the mass ratio of 1:2, it is added into a ball mill and ball milled under nitrogen protection. The parameters of the first ball milling are as follows: the preferred ratio of ball mass to material is 30:1, the rotation speed is preferably 1200rpm, the time is preferably 2h, the pressure is 0.05Mpa, the temperature is 50°C, and the grinding balls are zirconium dioxide balls to obtain the first ball milling powder. (3) After obtaining the first ball milling powder, the first ball milling powder is subjected to a second ball milling. The second ball milling ball to material ratio is preferably 30:1, the milling speed is preferably 1400rpm; the time is preferably 2h; the pressure is preferably 0.04Mpa; the temperature is preferably 60°C to obtain the second ball milling powder. (4) After obtaining the second ball milling powder, the second ball milling powder is subjected to the dilute sulfuric acid water with pH=4 to extract lithium, and the leaching rate reaches 98.79%.

[0023] Comparative Example 1: The difference from Example 2 is that no brominated epoxy resin is added. The specific steps are as follows: (1) waste NCM111 battery positive electrode material and ball milling agent Na 2 S 2 O 3According to the mass ratio of 1:2, it is added into a ball mill and ball milled under nitrogen protection. The parameters of the first ball milling are: the mass ratio of ball to material is 30:1, the speed is preferably 1200rpm, the time is 2h, the pressure is 0.05Mpa, the temperature is 50°C, and the grinding balls are zirconium dioxide balls to obtain the first ball milling powder. (2) After obtaining the first ball milling powder, the first ball milling powder is subjected to a second ball milling. The ball to material ratio of the second ball milling is preferably 30:1, the speed of the second ball milling is preferably 1400rpm; the second ball milling time is preferably 2h; the second ball milling pressure is preferably 0.04Mpa; the second ball milling temperature is preferably 60°C, to obtain the second ball milling powder. (3) After obtaining the second ball milling powder, the present invention uses the second ball milling powder to extract lithium with dilute sulfuric acid water at pH=4, and the leaching rate reaches 3.02%.

[0024] Comparative Example 2: The difference from Example 2 is that no ball milling agent is added. The specific steps are as follows: (1) The waste NCM111 battery positive electrode material and the brominated epoxy resin are ground and mixed in a mass ratio of 1:1 to obtain a mixed powder. (2) The mixed powder is added to a ball mill and ball milled under nitrogen protection. The parameters of the first ball milling are as follows: the mass ratio of the first ball milling ball material is 30:1, the first ball milling speed is preferably 1200rpm, the first ball milling time is 2h, the first ball milling pressure is 0.05Mpa, the first ball milling temperature is 50°C, and the grinding balls are zirconium dioxide balls to obtain a first ball milling powder. (3) After obtaining the first ball milling powder, the present invention performs a second ball milling on the first ball milling powder. The second ball milling ball material ratio is preferably 30:1, the second ball milling speed is preferably 1400rpm; the second ball milling time is preferably 2h; the second ball milling pressure is preferably 0.04Mpa; the second ball milling temperature is preferably 60°C, and the second ball milling powder is obtained. (4) After obtaining the secondary ball-milled powder, the present invention uses dilute sulfuric acid water with a pH of 4 to leach lithium from the secondary ball-milled powder, and the leaching rate reaches 64.88%.

[0025] Comparative Example 3: The difference from Example 2 is that no secondary ball milling is performed. The specific steps are as follows: (1) Grind and mix the waste NCM111 battery positive electrode material and brominated epoxy resin in a mass ratio of 1:1 to obtain a mixed powder. (2) Mix the mixed powder with a ball milling agent Na 2 S 2 O 3 According to the mass ratio of 1:2, it is added into a ball mill and ball milled under the protection of nitrogen inert atmosphere. The parameters of the first ball milling are as follows: the mass ratio of the first ball milling ball material is 30:1, the first ball milling speed is preferably 1200rpm, the first ball milling time is 2h, the first ball milling pressure is 0.05Mpa, the first ball milling temperature is 50℃, and the grinding balls are zirconium dioxide balls to obtain the first ball milling powder. (3) After obtaining the first ball milling powder, the first ball milling powder is subjected to the dilute sulfuric acid water with pH=4 to extract lithium, and the leaching rate reaches 58.21%.

Claims

1. A method for selectively extracting lithium from waste ternary lithium-ion battery cathode materials by ball milling, characterized in that: The specific steps are as follows: (1) ball-milling the waste ternary lithium-ion battery positive electrode material, brominated epoxy resin and ball milling agent under inert gas protection according to the primary ball milling parameters to obtain the primary ball milled powder; (2) performing secondary ball milling treatment on the primary ball milled powder obtained in step (1) according to the secondary ball milling parameters to obtain the secondary ball milled powder; (3) acid leaching the secondary ball milled powder obtained in step (2).

2. The method for selectively extracting lithium by ball milling waste ternary lithium-ion battery positive electrode materials according to claim 1, characterized in that: The waste ternary lithium-ion battery is NCM111, or NCM523, or NCM622, or NCM811, or a mixture of the above batteries.

3. The method for selectively extracting lithium by ball milling waste ternary lithium-ion battery positive electrode materials according to claim 1, characterized in that: The brominated epoxy resin is uncured or cured brominated epoxy resin, and mixed plastics rich in brominated epoxy resin.

4. The method for selectively extracting lithium by ball milling waste ternary lithium-ion battery positive electrode materials according to claim 1, characterized in that: The ball mill is SiO2, or Na2S2O3, or K2S2O3, or a mixture of the three.

5. The method for selectively extracting lithium by ball milling waste ternary lithium-ion battery positive electrode materials according to claim 1, characterized in that: The mass ratio of the waste ternary lithium-ion battery: brominated epoxy resin: ball mill is 1: (0.5-3): (1-5).

6. The method for selectively extracting lithium by ball milling waste ternary lithium-ion battery positive electrode materials according to claim 1, characterized in that: The inert gas is nitrogen, argon, helium, or a mixture of nitrogen, argon and helium in any volume ratio.

7. The method for selectively extracting lithium by ball milling waste ternary lithium-ion battery positive electrode materials according to claim 1, characterized in that: The primary ball milling parameters are as follows: the mass ratio of the primary ball milling ball to material is (20-50):1, the primary ball milling speed is 900-1400 rpm, the primary ball milling time is 0.5-3 h, the primary ball milling pressure is 0.01-0.05 MPa, and the primary ball milling temperature is 20-60° C.

8. The method for selectively extracting lithium by ball milling waste ternary lithium-ion battery positive electrode materials according to claim 1, characterized in that: The secondary ball milling parameters are: secondary ball milling ball-to-material mass ratio (30-50):1, secondary ball milling speed is 1100-1600 rpm, secondary ball milling time is 1-5 h, secondary ball milling pressure is 0.01-0.1 MPa, and secondary ball milling temperature is 40-70 °C.

9. The method for selectively extracting lithium by ball milling waste ternary lithium-ion battery positive electrode materials according to claim 1, characterized in that: The acid used for the acid leaching is dilute sulfuric acid, dilute nitric acid, dilute hydrochloric acid, or a mixed acid of dilute sulfuric acid, dilute nitric acid and dilute hydrochloric acid in any mass ratio, and the pH is 4-6.

10. The method for selectively extracting lithium by ball milling waste ternary lithium-ion battery positive electrode materials according to claim 1, characterized in that: The acid leaching solid-liquid ratio is 50-200 g / L, the leaching time is 1-3 hours, the leaching temperature is 40-70° C., and the stirring speed is 100-300 rpm.

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