CN111994966A - Method for recycling waste ternary positive electrode under high-temperature condition of hydrogen sulfide atmosphere - Google Patents

Abstract

The present invention designs a method for recycling waste ternary positive electrodes under high temperature conditions in a hydrogen sulfide atmosphere. The invention relates to a method for recycling waste ternary positive electrodes under high temperature conditions in a hydrogen sulfide atmosphere, belonging to the technical field of lithium ion battery material recycling. The method includes the following steps: in an argon-hydrogen atmosphere, supplemented by an appropriate amount of sulfur powder to generate an H ₂ S atmosphere; using H ₂ S and high temperature conditions to calcine waste and old ternary positive electrode materials; After that, the residual lithium, impurity aluminum and nickel-cobalt-manganese in the waste cathode material can be effectively separated; the primary liquid phase (residual lithium, impurity aluminum) is recovered by sodium carbonate precipitation, while the primary solid phase (nickel-cobalt-manganese sulfide) ), a secondary acid wash is required to redissolve and regenerate the ternary cathode material. The invention provides a new way for the recycling of waste lithium ion batteries.

Description

A method for recycling waste ternary positive electrode under high temperature conditions of manufacturing hydrogen sulfide atmosphere

technical field

The invention belongs to the technical field of lithium ion battery material recovery, in particular to a method for high-temperature roasting, selective recovery of valuable metals in ternary positive electrode materials of waste lithium ion batteries, and regeneration of precursors.

Background technique

The excellent performance of lithium-ion batteries has brought them a very wide application market, so their production is increasing, but there is also a problem - a large number of waste lithium-ion batteries need to be recycled. Waste lithium-ion batteries are called "urban mines" because they are rich in a variety of valuable metals, which also ensures the economic value of their recycling. Taking the ternary nickel-cobalt-manganese cathode material as an example, to explore how to recover the organic metals in it simply and efficiently. As the recovery process with the most industrialization potential, wet acid leaching has the advantages of large and fast processing capacity and low requirements for processing objects. However, it will inevitably introduce various impurities into the leaching solution, causing subsequent metal separation difficulties, making the overall The technological process is lengthy and complex. In addition, in addition to the influence of impurities, a large amount of lithium remains in the cathode material of the battery at the end of life or failure, and enters the leaching solution with the leaching process, which hinders the possibility of directly using the leaching solution for material regeneration.

At present, there are a large number of relevant research reports on the recycling of ternary nickel-cobalt-manganese cathode materials for waste lithium-ion batteries. For example, in Chinese patent CN108103323A, by discharging, disassembling, soaking in organic solvent and calcining in an oxygen atmosphere, the obtained material retains the activity of the positive electrode material and achieves the purpose of recycling and regeneration; another example is Chinese patent CN107699692A, which uses organic acid leaching, By adjusting the pH value of the leaching solution, gel or precipitate is obtained, and then calcined and ground for regeneration to obtain lithium ion battery materials; there is also Chinese patent CN105789726A, which is obtained by acid washing-sodium hydroxide iron removal-adjusting nickel-cobalt-manganese concentration-sodium carbonate co-precipitation. Nickel-cobalt-manganese ternary precursor. It is not difficult to find that the above research reports do not consider the influence of residual lithium or impurities (aluminum impurities introduced by aluminum foil) on recycled materials, so a more complete process is needed to solve the influence of residual lithium and aluminum impurities, and obtain excellent performance. of recycled materials.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to solve the problems of residual lithium and impurity aluminum that are not touched in the traditional recovery and regeneration process, and the present invention provides a selective separation and recovery method. The purpose is to effectively separate the residual lithium and impurity aluminum in the waste cathode material from the main recycling object (nickel-cobalt-manganese) through high-temperature roasting and citric acid pickling in the production of H ₂ S atmosphere, and reuse nickel-cobalt-manganese for regeneration. 523 ternary precursor. While the recycling process is simplified, it also ensures that the structural properties of the recycled ternary precursor material are not affected by residual lithium and impurity aluminum.

The object of the present invention is achieved through the following technical solutions, a method of manufacturing hydrogen sulfide atmosphere high temperature condition recycling waste ternary positive electrode, comprising the steps as follows:

Step (1): place the waste ternary cathode material in an argon-hydrogen atmosphere, supplemented with sulfur powder, generate an H ₂ S atmosphere in a high temperature environment, and convert the metal oxide in the waste into sulfide;

Step (2): adopt citric acid solution to carry out a pickling to the calcination product obtained in step (1), utilize the material solubility difference to achieve the effect of separating impurities, namely liquid phase (residual lithium, impurity aluminum) and solid phase (nickel) sulfides of cobalt and manganese);

Step (3): the lithium ions in the primary liquid phase in the step (2) can be recovered by adding sodium carbonate to obtain lithium carbonate precipitation, and the nickel cobalt manganese in the primary solid phase can enter the liquid phase again through secondary acid leaching, is the ternary precursor solution;

Step (4): adjust the metal ratio of the precursor solution to Ni:Co:Mn=5:2:3 by adding soluble metal salt, then adjust the pH value with concentrated ammonia water and concentrated NaOH solution, and coprecipitate to obtain a ternary precursor.

Further, in step (1), the used amount and mass ratio of the waste positive electrode material and the sulfur powder is 1:2-5, the proportion of hydrogen in the argon-hydrogen atmosphere is 5-10%, the calcination temperature is 600-1000 ° C, and the holding time is 0.5～3h.

Further, the concentration of the citric acid solution in step (2) is 1-8 mol/L, the reaction temperature is 20-100° C., and the reaction time is 0.5-2 h.

Further, the acid used in the secondary pickling process in step (3) is one of sulfuric acid and hydrochloric acid, and the concentration is 1-6 mol/L, the reaction temperature is 20-100° C., and the reaction time is 0.5-2 h.

Further, the pH regulation in step (4) is 10-14.

Beneficial effects of the present invention:

(1) Using sulfur powder and argon-hydrogen protective gas to control the content of the generated H ₂ S atmosphere, metal oxides in waste ternary materials can be efficiently converted into sulfides.

(2) Nickel-cobalt-manganese sulfide cannot be dissolved in citric acid solution, and the acidity of citric acid can accelerate the dissolution process of lithium sulfide and aluminum sulfide (the reaction generates H ₂ S gas to make the dissolution process proceed forward), which greatly reduces the Negative effects of residual lithium and impurity aluminum in small wastes on subsequent regeneration of ternary materials. Further utilizing the different properties of carbonates, lithium metal can be recovered by precipitation from the liquid phase containing impurity aluminum.

(3) The separation of impurities and the preparation of the precursor solution shorten the overall process flow, avoid the lengthy process of multi-metal recovery in stages, and the practical value of recycled materials ensures the benefits of recovery.

Description of drawings

Fig. 1 is the recycling flow chart of the present invention;

Fig. 2 is the SEM image of the product prepared in Example 1 of the present invention;

Fig. 3 is the SEM image of the product prepared in Example 2 of the present invention;

FIG. 4 is a SEM image of the product prepared in Example 3 of the present invention.

Detailed ways

The present invention will be further described below in conjunction with the examples.

Example 1

(1) The waste ternary cathode material is placed in an argon-hydrogen atmosphere (5% _H2 content), supplemented with sulfur powder, wherein the mass ratio of the cathode to the sulfur powder is 1:2, the calcination temperature is 800 °C, and the temperature is kept warm. The time is 2h, and it is calcined in a tube furnace;

(2) after cooling the obtained calcined product, pass through a 1 mol/L citric acid solution at 25 ° C, react for 1 h, and filter to obtain a liquid phase and a solid phase;

(3) adding the obtained solid phase to a 2mol/LH ₂ SO ₄ solution, and reacting at 25° C. for 1 h to obtain a ternary precursor solution;

(4) adding corresponding sulfate to adjust the ratio of nickel, cobalt and manganese in the solution to 5:2:3, then using concentrated ammonia water and concentrated sodium hydroxide solution to adjust and control the pH to 10, and co-precipitate to form a nickel-cobalt-manganese ternary precursor .

Example 2

(1) The waste ternary positive electrode material is placed in an argon hydrogen atmosphere ( ₅ % H content), supplemented with sulfur powder, wherein the mass ratio of the positive electrode to the sulfur powder is 1:3, the calcination temperature is 900 °C, and the temperature is kept warm. The time is 3h, and it is calcined in a tube furnace;

(2) after cooling the obtained calcined product, pass through a 2mol/L citric acid solution at 40°C, react for 1h, and filter to obtain a liquid phase and a solid phase;

(3) adding the obtained solid phase to a 2mol/LH ₂ SO ₄ solution, and reacting at 40° C. for 1 h to obtain a ternary precursor solution;

(4) adding corresponding sulfate to adjust the ratio of nickel, cobalt and manganese in the solution to 5:2:3, then using concentrated ammonia water and concentrated sodium hydroxide solution to adjust and control the pH to 10, and co-precipitate to form a nickel-cobalt-manganese ternary precursor .

Example 3

(1) The waste ternary positive electrode material is placed in an argon hydrogen atmosphere ( ₅ % H content), supplemented with sulfur powder, wherein the mass ratio of the positive electrode to the sulfur powder is 1:4, the calcination temperature is 900 °C, and the temperature is kept warm. The time is 2h, and it is calcined in a tube furnace;

(2) after cooling the obtained calcined product, pass through a 1 mol/L citric acid solution at 60 ° C, react for 1 h, and filter to obtain a liquid phase and a solid phase;

(3) adding the obtained solid phase to a 2mol/LH ₂ SO ₄ solution, and reacting at 60° C. for 1 h to obtain a ternary precursor solution;

(4) adding corresponding sulfate to adjust the ratio of nickel, cobalt and manganese in the solution to 5:2:3, then using concentrated ammonia water and concentrated sodium hydroxide solution to adjust and control the pH to 10, and co-precipitate to form a nickel-cobalt-manganese ternary precursor .

The above content is only a basic description under the concept of the present invention, and any equivalent transformation made according to the technical solution of the present invention shall belong to the protection scope of the present invention.

Claims (5)

1. A method for recycling a waste ternary positive electrode under a high-temperature condition in a hydrogen sulfide atmosphere is characterized by comprising the following steps of:

step (1): waste ternary positive electrode material is placed in argon-hydrogen atmosphere, and is supplemented with sulfur powder to generate H in high-temperature environment₂S atmosphere, and converting the metal oxide in the waste into sulfide;

step (2): performing primary acid washing on the roasted product obtained in the step (1) by using a citric acid solution, and achieving the effect of separating impurities by using the solubility difference of substances, namely a liquid phase (residual lithium and impurity aluminum) and a solid phase (sulfide of nickel, cobalt and manganese);

and (3): lithium ions in the primary liquid phase in the step (2) can be recovered by adding sodium carbonate to obtain lithium carbonate precipitate, and nickel, cobalt and manganese in the primary solid phase can enter the liquid phase again through secondary acid leaching to obtain a ternary precursor solution;

and (4): and (3) adding soluble metal salt to adjust the metal ratio of the precursor solution to Ni, Co and Mn, namely 5:2:3, adjusting the pH value by adopting concentrated ammonia water and concentrated NaOH solution, and carrying out coprecipitation to obtain the ternary precursor.

2. The method for manufacturing the waste ternary positive electrode under the high-temperature hydrogen sulfide atmosphere condition is characterized in that the using amount mass ratio of the waste positive electrode material and the sulfur powder in the step (1) is 1: 2-5, the proportion of hydrogen in the argon-hydrogen atmosphere is 5-10%, the calcining temperature is 600-1000 ℃, and the heat preservation time is 0.5-3 h.

3. The method for manufacturing the waste ternary positive electrode under the high-temperature hydrogen sulfide atmosphere condition according to claim 1 or 2, wherein the concentration of the citric acid solution in the step (2) is 1-8 mol/L, the reaction temperature is 20-100 ℃, and the reaction time is 0.5-2 hours.

4. The method for manufacturing the waste ternary positive electrode under the high-temperature condition of the hydrogen sulfide atmosphere according to any one of claims 1 to 3, wherein the acid adopted in the secondary acid leaching process in the step (3) is one of sulfuric acid and hydrochloric acid, the concentration of the acid is 1-6 mol/L, the reaction temperature is 20-100 ℃, and the reaction time is 0.5-2 hours.

5. The method for manufacturing the waste ternary positive electrode under the high-temperature hydrogen sulfide atmosphere according to any one of claims 1 to 4, wherein the pH in the step (4) is controlled to be 10 to 14.

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