Method for recovering lithium from ternary pole piece waste

Abstract

The invention relates to the technical field of lithium ion battery recovery, in particular to a method for recovering lithium from ternary pole piece waste, which comprises the following steps: pretreating a waste battery positive pole piece, and sorting a positive pole material; adding carbon powder, shaking and uniformly mixing, putting into a crucible with a cover, and finally putting the crucible into a high-temperature furnace for roasting to obtain a roasted material; carrying out ball milling and slurrying on the roasted material, introducing carbon dioxide for reaction, and carrying out suction filtration to obtain a leaching solution and nickel-cobalt slag; the method comprises the following steps: stripping a positive pole material from a positive pole piece of a lithium battery, adding carbon powder, roasting to reduce high-valence nickel, cobalt and manganese into divalent nickel, cobalt and manganese, promoting leaching of Li, carrying out ball milling and slurrying on the powder, introducing CO2, changing Li into soluble LiHCO3, carrying out liquid-solid separation, removing impurities, and heating to prepare the battery-grade lithium carbonate. According to the method, a pyrogenic process and a wet process are combined for leaching, acid leaching is replaced by CO2 leaching, extra alkali is avoided, and the recovery economic benefit is high.

Description

Technical Field

[0001] The invention relates to the technical field of lithium ion battery recycling, and in particular to a method for recycling lithium from ternary pole piece waste. Background Art

[0002] Electric vehicles are gradually becoming a development trend in the next few decades. A large number of metals such as Ni, Co, Mn, Al, and Cu are used in the positive electrode materials of lithium-ion batteries. Considering the impact on energy consumption and the environment, the overall cost of resource utilization of waste secondary batteries is lower. Therefore, how to eliminate waste battery pollution from the source and realize the clean recovery and recycling of waste lithium-ion batteries is a hot issue affecting the global energy strategic pattern.

[0003] At present, the methods for recovering valuable metals from the positive electrode materials of waste ternary lithium batteries with a high degree of industrialization mainly include wet leaching and pyrolysis. Among them, the wet leaching method mainly uses inorganic acids (such as hydrochloric acid, nitric acid, sulfuric acid and other strong acids) as leaching agents, and adds sodium bisulfite, hydrogen peroxide and the like as reducing agents to leach lithium from the positive electrode materials of waste ternary lithium batteries, and then separates the lithium-rich solution through chemical precipitation, extraction and other methods.

[0004] In the prior art, although the full-component leaching process has a high metal recovery rate and high product purity, the process flow is long, the operation is complicated, the acid and alkali consumption is large during the leaching and precipitation process, and the process recovery economic benefits are poor. Summary of the invention

[0005] The purpose of the present invention is to provide a method for recovering lithium from ternary electrode waste, aiming to solve the problem of large acid and alkali consumption in the leaching and precipitation process and poor recovery economic benefits of the existing wet leaching method.

[0006] To achieve the above object, the present invention provides a method for recovering lithium from ternary electrode waste, comprising the following steps:

[0007] Crushing and pre-processing of waste battery positive electrode sheets and sorting of positive electrode materials;

[0008] Adding carbon powder to the positive electrode material, shaking and mixing, and then putting it into a crucible with a cover, and finally placing the crucible into a high-temperature furnace for roasting to obtain a roasted material;

[0009] The calcined material is ball-milled, slurried, carbon dioxide is introduced for reaction, and filtered to obtain a leaching solution and nickel-cobalt slag;

[0010] The leaching solution is impurity-removed and heated to precipitate lithium carbonate and prepare battery-grade lithium carbonate.

[0011] Wherein, the mass ratio of the carbon powder is 1-10%.

[0012] Wherein, the calcination temperature is 600-750°C, and the calcination time is 1-3h.

[0013] Wherein, the slurry-solid ratio is 3 to 5:1.

[0014] Wherein, in the carbon dioxide introduction reaction, the carbon dioxide introduction amount is 1 to 10 L / min, the reaction temperature is 0 to 25° C., and the reaction time is 0.5 to 2 h.

[0015] The invention discloses a method for recovering lithium from waste ternary electrode sheets, comprising the steps of crushing and pre-treating waste battery positive electrode sheets and sorting positive electrode materials; adding carbon powder to the positive electrode materials, oscillating and mixing, and then loading the positive electrode materials into a crucible with a cover, and finally placing the crucible into a high-temperature furnace for roasting to obtain roasted materials; ball milling and pulping the roasted materials, introducing carbon dioxide for reaction, and filtering to obtain a leaching solution and nickel-cobalt slag; removing impurities from the leaching solution and heating it to precipitate lithium carbonate and prepare battery-grade lithium carbonate. The method obtains positive electrode materials by peeling off the positive electrode sheets of ternary lithium batteries, and then adding carbon powder and roasting the leaching solution. The high-valent nickel, cobalt and manganese are reduced to divalent states to promote the leaching of Li, and then the calcined powder is ball-milled and slurried, and CO2 is introduced into it to convert Li into soluble LiHCO3. After liquid-solid separation, impurities are further removed and then heated to make battery-grade lithium carbonate. This method combines the pyrometallurgical method with the wet method for combined leaching, and uses CO2 leaching instead of acid leaching, which reduces the pH adjustment process and avoids the use of additional alkali. It is acid-free leaching with high recovery economic benefits, and solves the problem of large acid and alkali consumption and poor recovery economic benefits in the existing wet leaching method during the leaching and precipitation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 The present invention provides a flowchart of recovering lithium from ternary electrode waste.

[0018] Figure 2 It is a quantitative analysis diagram of elements in the positive electrode material of waste ternary lithium batteries used in the embodiments of the present invention.

[0019] Figure 3 The present invention provides a flow chart of a method for recovering lithium from ternary electrode waste. DETAILED DESCRIPTION

[0020] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0021] See also Figures 1 to 3 The present invention provides a method for recovering lithium from ternary electrode waste, comprising the following steps:

[0022] S1 crushes and pre-processes the cathode sheets of used batteries and sorts the cathode materials;

[0023] S2: adding carbon powder to the positive electrode material, shaking and mixing, and then putting it into a crucible with a cover, and finally placing the crucible into a high-temperature furnace for roasting to obtain a roasted material;

[0024] In an embodiment of the present invention, 1 to 10% (mass ratio) of carbon powder (which may be acetylene black or activated carbon) is added to the positive electrode material of the waste ternary lithium battery, mixed by shaking, loaded into a crucible with a lid, and finally placed in a high-temperature furnace (laboratory muffle furnace) and calcined at 600 to 750° C. for 1 to 3 hours.

[0025] S3 ball-milling the calcined material, slurrying it, introducing carbon dioxide into it for reaction, and filtering it to obtain a leaching solution and nickel-cobalt slag;

[0026] In an embodiment of the present invention, the calcined material is ball-milled and slurried at a liquid-to-solid ratio of 3 to 5:1, with a CO2 ventilation rate of 1 to 10 L / min. After reacting for 0.5 to 2 hours at a temperature of 0 to 25°C, the leaching solution and nickel-cobalt slag are obtained by suction filtration.

[0027] S4 removes impurities from the leaching solution and heats it to precipitate lithium carbonate and prepare battery-grade lithium carbonate.

[0028] In an embodiment of the present invention, after the impurities are removed from the leachate, the lithium carbonate is precipitated by heating, and the precipitated lithium carbonate is made into battery-grade lithium carbonate.

[0029] In order to better understand the present technical solution, the following embodiments are provided for further explanation:

[0030] Raw materials: The waste ternary lithium battery positive electrode material used in the embodiment of the present invention is obtained by pretreatment. The quantitative analysis of the elements is as follows: Figure 2 As shown:

[0031] Example 1

[0032] Reduction roasting: Weigh 200g of waste ternary lithium battery positive electrode material and 8g of acetylene black, mix them evenly and put them in a crucible, put them in a muffle furnace and roast them at 650℃ for 1.5h.

[0033] Hydrogenation: The roasted material was slurried at a liquid-to-solid ratio of 3:1, with a CO2 ventilation rate of 5 L / min. After reacting at 25°C for 2 hours, it was filtered to obtain a leachate and nickel-cobalt slag.

[0034] The hydrogenated leaching solution is refined and then heated to precipitate lithium carbonate to produce battery-grade lithium carbonate.

[0035] According to the national standard GB / T 11064.1-2013, the main content of lithium carbonate is measured by titration method: 99.60%.

[0036] Example 2

[0037] Oxidation roasting: Weigh 200g of waste ternary lithium battery positive electrode material and 8g of acetylene black, mix them evenly and put them in a crucible, put them in a muffle furnace and roast them at 650℃ for 1.5h.

[0038] Hydrogenation: The roasted material was slurried at a liquid-to-solid ratio of 4:1, with a CO2 ventilation rate of 3L / min. After reacting at 15°C for 1h, the leaching solution and nickel-cobalt slag were obtained by filtration.

[0039] The hydrogenated leaching solution is refined and then heated to precipitate lithium carbonate to produce battery-grade lithium carbonate.

[0040] According to the national standard GB / T 11064.1-2013, the main content of lithium carbonate is measured by titration method: 99.63%.

[0041] Example 3

[0042] Oxidation roasting: Weigh 200g of waste ternary lithium battery positive electrode material and 12g of activated carbon, mix them evenly and put them in a crucible, put them in a muffle furnace and roast them at 650℃ for 1.5h.

[0043] Hydrogenation: The roasted material was slurried at a liquid-to-solid ratio of 5:1, with a CO2 ventilation rate of 1 L / min. After reacting at 5°C for 0.5 h, the leaching solution and nickel-cobalt slag were obtained by filtration.

[0044] The hydrogenated leaching solution is refined and then heated to precipitate lithium carbonate to produce battery-grade lithium carbonate.

[0045] According to the national standard GB / T 11064.1-2013, the main content of lithium carbonate is measured by titration method: 99.65%.

[0046] The above disclosure is only a preferred embodiment of a method for recovering lithium from ternary electrode waste of the present invention. Of course, it cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiments and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A method for recovering lithium from ternary electrode waste, characterized in that: The following steps are involved: Crushing and pre-processing of waste battery positive electrode sheets and sorting of positive electrode materials; Adding carbon powder to the positive electrode material, shaking and mixing, and then putting it into a crucible with a cover, and finally placing the crucible into a high-temperature furnace for roasting to obtain a roasted material; The calcined material is ball-milled, slurried, carbon dioxide is introduced for reaction, and filtered to obtain a leaching solution and nickel-cobalt slag; The leaching solution is impurity-removed and heated to precipitate lithium carbonate and prepare battery-grade lithium carbonate.

2. The method for recovering lithium from ternary electrode waste according to claim 1, characterized in that ； The mass ratio of the carbon powder is 1 to 10%.

3. The method for recovering lithium from ternary electrode waste according to claim 1, characterized in that ； The calcination temperature is 600-750° C., and the calcination time is 1-3 hours.

4. The method for recovering lithium from ternary electrode waste according to claim 1, characterized in that ； The slurry-to-solid ratio is 3 to 5:

1.

5. The method for recovering lithium from ternary electrode waste according to claim 1, It is characterized by: In the carbon dioxide introduction reaction, the carbon dioxide introduction amount is 1 to 10 L / min, the reaction temperature is 0 to 25° C., and the reaction time is 0.5 to 2 h.

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