A method for selectively extracting lithium from the cathode material of waste ternary lithium-ion batteries by ball milling

Abstract

The present invention relates to the technical field of resource recycling and reuse, in particular to a method for selectively extracting lithium by ball milling of the cathode material of waste ternary lithium-ion batteries. The present invention discloses a method, which includes mixing the cathode material of waste ternary lithium-ion batteries with brominated epoxy resin, and then performing ball milling treatment with a ball milling agent under nitrogen protection to obtain primary ball mill powder. Then, the primary ball mill powder is subjected to secondary ball milling to obtain secondary ball mill powder, and finally acid leaching treatment is carried out to achieve selective lithium extraction. According to the embodiments, the present invention can effectively solve the problems of high lithium loss, low lithium leaching rate, and poor lithium selectivity existing in the traditional waste lithium battery recycling methods. In addition, the operation of the present invention is simple, and valuable metal lithium in the cathode material of waste ternary lithium-ion batteries can be selectively recycled.

Description

Technical Field

[0001] The present invention belongs to the technical field of recycling and reusing waste lithium battery resources, and particularly 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 climb. 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. This not only accelerates the consumption of natural resources such as lithium, nickel, cobalt, and manganese, but also urgently requires recycling due to the high-value metals contained in the waste batteries to improve the recycling rate of resources. In addition, the toxic and harmful substances contained in the batteries pose a potential threat to soil and water sources. Therefore, an efficient and environmentally friendly resource recovery technology for waste ternary lithium-ion batteries is particularly important and has great practical value.

[0003] Currently, the technologies for recycling waste ternary lithium-ion batteries mainly include pyrometallurgy, hydrometallurgy, and direct recycling and regeneration methods. Hydrometallurgy has problems such as a long process, difficulty in separating multiple metals, lithium loss during the recovery process, and the 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 the emission of toxic waste gases. Therefore, developing an efficient and environmentally friendly method for selectively extracting lithium from the cathode material of waste ternary lithium-ion batteries has obvious economic value and social benefits. Summary of the Invention

[0004] The present invention proposes a method for selectively extracting lithium from the cathode material of waste ternary lithium-ion batteries by ball milling. This method uses ball milling for selective lithium extraction. During the ball milling process, brominated epoxy resin decomposes into hydrogen bromide, small molecule hydrocarbons, and carbon under the action of mechanochemical force. The generated hydrogen bromide reacts with the cathode material of waste ternary lithium-ion batteries to produce a bromination reaction, and the generated small molecule hydrocarbons can react with the cathode material of waste ternary lithium-ion batteries to produce a reduction reaction, thereby realizing the selective extraction of lithium. This method has the advantages of low energy consumption, low pollution, and high selectivity.

[0005] To achieve the above object, the present invention proposes a method for selectively extracting lithium from the cathode material of waste ternary lithium-ion batteries by ball milling, and the specific steps are as follows: (1) Ball mill the cathode material of waste ternary lithium-ion batteries, brominated epoxy resin, and ball milling agent under the protection of an inert gas according to the primary ball milling parameters to obtain primary ball mill powder; (2) Perform secondary ball milling treatment on the primary ball mill powder obtained in step (1) according to the secondary ball milling parameters to obtain secondary ball mill powder; (3) Acid leach the secondary ball mill 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] In the step (1), the brominated epoxy resin is uncured or cured brominated epoxy resin, and a mixed plastic rich in brominated epoxy resin.

[0008] In the step (1), the ball milling agent 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 milling agent is 1: (0.5 - 3): (1 - 5).

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

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

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

[0013] In the acid leaching in the step (3), the acid used is dilute sulfuric acid, or dilute nitric acid, or 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.

[0014] In the acid leaching 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 rate 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 a grinding agent is added 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 waste ternary lithium-ion batteries 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: grinding agent of 1:1:2, the blue line represents the mass ratio of waste ternary lithium-ion battery: grinding agent of 1:2, and the red line represents the mass ratio of waste ternary lithium-ion battery: brominated epoxy resin of 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: grinding agent of 1:1:2, the blue line represents the mass ratio of waste ternary lithium-ion battery: grinding agent of 1:2, and the red line represents the mass ratio of waste ternary lithium-ion battery: brominated epoxy resin of 1:1. DETAILED DESCRIPTION OF THE INVENTION

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

[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 Add them to a ball mill according to a mass ratio of 1:2 and perform ball milling under nitrogen protection. The parameters for the first ball milling are as follows: the mass ratio of balls to materials is 30:1, the rotation speed is 900 rpm, the time is 2 h, the pressure is 0.05 Mpa, and the temperature is 50 °C. The parameters used are not under the optimal conditions. The grinding balls are zirconia balls, and the first ball-milled powder is obtained. (3) After obtaining the first ball-milled powder, perform secondary ball milling on the first ball-milled powder. The preferred ball-to-material ratio for the secondary ball milling is 30:1, the rotation speed is preferably 1400 rpm; the time is preferably 2 h; the pressure is preferably 0.04 Mpa; the temperature is preferably 60 °C, and the second ball-milled powder is obtained. (4) After obtaining the second ball-milled powder, perform leaching of lithium with dilute sulfuric acid with a pH of 4 on the second ball-milled powder, and the leaching rate reaches 96.11%.

[0022] Example 2: This example is a method for selectively extracting lithium by ball milling of waste ternary lithium-ion battery cathode materials, including the following steps: (1) Grind and mix waste NCM111 battery cathode materials 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 2 S 2 O 3 Add them to a ball mill according to a mass ratio of 1:2 and perform ball milling under nitrogen protection. The parameters for the first ball milling are as follows: the preferred mass ratio of balls to materials is 30:1, the rotation speed is preferably 1200 rpm, the time is preferably 2 h, the pressure is 0.05 Mpa, and the temperature is 50 °C. The grinding balls are zirconia balls, and the first ball-milled powder is obtained. (3) After obtaining the first ball-milled powder, perform secondary ball milling on the first ball-milled powder. The preferred ball-to-material ratio for the secondary ball milling is 30:1, the grinding rotation speed is preferably 1400 rpm; the time is preferably 2 h; the pressure is preferably 0.04 Mpa; the temperature is preferably 60 °C, and the second ball-milled powder is obtained. (4) After obtaining the second ball-milled powder, in the present invention, perform leaching of lithium with dilute sulfuric acid with a pH of 4 on the second ball-milled powder, and the leaching rate reaches 98.79%.

[0023] Comparative Example 1: The difference from Example 2 is that brominated epoxy resin is not added. The specific steps are as follows: (1) Mix waste NCM111 battery cathode materials and the ball milling agent Na 2 S 2 O 3Add them to a ball mill according to a mass ratio of 1:2 and carry out ball milling under nitrogen protection. The parameters of the first ball milling are as follows: the mass ratio of balls to materials is 30:1, the speed is preferably 1200 rpm, the time is 2 h, the pressure is 0.05 Mpa, the temperature is 50 °C, and the grinding balls are zirconia balls, thus obtaining the first ball-milled powder. (2) After obtaining the first ball-milled powder, carry out secondary ball milling on the first ball-milled powder. The ball-to-material ratio of the secondary ball milling is preferably 30:1, and the rotation speed of the secondary ball milling is preferably 1400 rpm; the time of the secondary ball milling is preferably 2 h; the pressure of the secondary ball milling is preferably 0.04 Mpa; the temperature of the secondary ball milling is preferably 60 °C, thus obtaining the second ball-milled powder. (3) After obtaining the second ball-milled powder, the present invention carries out water leaching of lithium with dilute sulfuric acid with pH = 4 on the second ball-milled powder, 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) Grind and mix the waste NCM111 cathode material and brominated epoxy resin according to a mass ratio of 1:1 to obtain a mixed powder. (2) Add the above mixed powder to a ball mill and carry out ball milling under nitrogen protection. The parameters of the first ball milling are as follows: the mass ratio of balls to materials in the first ball milling is 30:1, the rotation speed of the first ball milling is preferably 1200 rpm, the time of the first ball milling is 2 h, the pressure of the first ball milling is 0.05 Mpa, the temperature of the first ball milling is 50 °C, and the grinding balls are zirconia balls, thus obtaining the first ball-milled powder. (3) After obtaining the first ball-milled powder, the present invention carries out secondary ball milling on the first ball-milled powder. The ball-to-material ratio of the secondary ball milling is preferably 30:1, and the rotation speed of the secondary ball milling is preferably 1400 rpm; the time of the secondary ball milling is preferably 2 h; the pressure of the secondary ball milling is preferably 0.04 Mpa; the temperature of the secondary ball milling is preferably 60 °C, thus obtaining the second ball-milled powder. (4) After obtaining the second ball-milled powder, the present invention carries out water leaching of lithium with dilute sulfuric acid with pH = 4 on the second 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 carried out. The specific steps are as follows: (1) Grind and mix the waste NCM111 cathode material and brominated epoxy resin according to a mass ratio of 1:1 to obtain a mixed powder. (2) Add the above mixed powder and the ball milling agent Na 2 S 2 O 3 Add them to a ball mill according to a mass ratio of 1:2 and carry out ball milling under nitrogen inert atmosphere protection. The parameters of the first ball milling are as follows: the mass ratio of balls to materials in the first ball milling is 30:1, the rotation speed of the first ball milling is preferably 1200 rpm, the time of the first ball milling is 2 h, the pressure of the first ball milling is 0.05 Mpa, the temperature of the first ball milling is 50 °C, and the grinding balls are zirconia balls, thus obtaining the first ball-milled powder. (3) After obtaining the first ball-milled powder, carry out water leaching of lithium with dilute sulfuric acid with pH = 4 on the first ball-milled powder, 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 primary ball milled powder; (2) subjecting the primary ball milled powder obtained in step (1) to secondary ball milling treatment according to the secondary ball milling parameters to obtain secondary ball milled powder; (3) subjecting the secondary ball milled powder obtained in step (2) to acid leaching treatment for selective lithium extraction, wherein the ball milling agent is Na2S2O3, or K2S2O3, or a mixture of the two.

2. According to claim 1, a method for selectively extracting lithium by ball milling waste ternary lithium-ion battery positive electrode materials, characterized in that: The waste ternary lithium-ion battery is NCM111, NCM523, NCM622, or NCM811, and the brominated epoxy resin is uncured or cured brominated epoxy resin.

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 mass ratio of the waste ternary lithium-ion battery: brominated epoxy resin: ball mill is 1: (0.5-3): (1-5), and the inert gas is nitrogen or argon.

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 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, and the primary ball milling time is 0.5-3 h.

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 secondary ball milling parameters are: secondary ball milling ball-to-material mass ratio (30-50):1, secondary ball milling speed is 1100-1600 rpm, and secondary ball milling time is 1-5 h.

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 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.

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 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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