A method for defluorinating black powder from lithium batteries

Abstract

The present application specifically discloses a method for defluorinating lithium battery black powder, the method comprising the following steps: S100, uniformly mixing lithium battery black powder and a reaction gas at a first preset temperature to obtain a battery black powder mixture, wherein the reaction gas comprises at least one of water, alkanes, alkenes, alcohols, and alkyl organic acids; S200, heating the battery black powder mixture to a second preset temperature and reacting at a constant temperature; S300, extracting the gas phase generated by the constant temperature reaction, then filling it with a protective gas and cooling it to room temperature to obtain the defluorinated lithium battery black powder. The method for defluorinating lithium battery black powder provided in the present application utilizes a reaction gas to convert fluoride ions in the lithium battery black powder into hydrogen fluoride and then extracts it, so that the fluoride ions in the lithium battery black powder are effectively removed, and has the characteristics of simple process, low cost and good removal effect.

Description

Technical Field

[0001] The present application belongs to the technical field of lithium battery black powder recovery and treatment, and in particular, relates to a method for defluorination treatment of lithium battery black powder. Background Art

[0002] Lithium batteries include lithium iron phosphate batteries, ternary lithium batteries and other types of lithium batteries. After the lithium battery reaches the end of its service life, the corresponding lithium battery black powder can be obtained through mechanical crushing, air separation and other steps. The lithium battery black powder includes positive electrode black powder and negative electrode black powder, which contains organic matter, electrolyte salts, lithium, nickel, cobalt, manganese, copper, aluminum, fluorine, carbon and other elements. In order to maximize resource utilization, most of the nickel, cobalt, manganese and lithium in the battery black powder are currently recycled, but the fluorine element in the battery black powder has a great influence on the subsequent recycling and processing. Therefore, the present application provides a method for defluorination of lithium battery black powder. Summary of the invention

[0003] This application is made in view of the above technical problems and aims to provide a defluorination treatment method for lithium battery black powder, which is used to reduce the fluorine element in the battery black powder to improve the subsequent lithium recovery rate and thus improve the economic benefits.

[0004] In order to solve the above technical problems, the present application provides a method for defluorination treatment of lithium battery black powder, the method comprising the following steps:

[0005] S100, uniformly mixing lithium battery black powder and a reaction gas at a first preset temperature to obtain a battery black powder mixture, wherein the reaction gas includes at least one of water, alkanes, alkenes, alcohols, and alkyl organic acids, and the first preset temperature is 110-170° C.;

[0006] S200, heating the lithium battery black powder mixture to a second preset temperature and reacting at a constant temperature, wherein the second preset temperature is 500-800° C., and the constant temperature reaction time is 0.5-2 hours;

[0007] S300, extracting the gas phase generated by the isothermal reaction, then filling it with a protective gas and cooling it to room temperature, so as to obtain the defluorinated lithium battery black powder, wherein the protective gas is one of nitrogen, helium or argon.

[0008] In the above-mentioned lithium battery black powder defluorination treatment method, the lithium battery black powder and the reaction gas are first mixed and stirred evenly; then the stirred evenly stirred battery black powder mixture is heated to the required second preset temperature and kept warm for reaction, thereby converting all the fluorine elements in the battery black powder mixture into hydrogen fluoride, wherein the isothermal reaction time is 0.5-3h, and the isothermal reaction reaction formula includes:

[0009] F - + H + → HF

[0010] 2C+O 2- → 2CO;

[0011] Since the hydrogen fluoride generated by the reaction is mixed with part of the reaction gas in the gas phase, the gas phase can be separated from the solid phase of the lithium battery black powder by extraction; finally, the solid phase is cooled to room temperature by filling with protective gas to obtain the defluorinated lithium battery black powder. This method can effectively remove the fluorine element from the lithium battery black powder, providing a strong guarantee for the subsequent recycling and treatment of the lithium battery black powder. Therefore, the lithium battery black powder defluorination treatment method provided in this application has the characteristics of simple process, low cost and good defluorination effect.

[0012] In some embodiments, step S100 is specifically as follows: loading lithium battery black powder into a rotary tube furnace, filling it with protective gas to exhaust air, and then heating it to a first preset temperature and continuously introducing reaction gas to exhaust the protective gas in the rotary tube furnace and mix the reaction gas and lithium battery black powder evenly to obtain a battery black powder mixture.

[0013] In some embodiments, the reaction gas includes at least one of water, methane, ethylene, methanol, and formic acid.

[0014] In some embodiments, the step S300 is specifically as follows: closing the reaction gas and extracting the gas phase generated by the isothermal reaction, then filling with protective gas and cooling to room temperature at a cooling rate of 5°C / min, opening the rotary tube furnace, and obtaining the defluorinated lithium battery black powder.

[0015] In some embodiments, negative pressure extraction is used to extract the gas phase in the rotary tube furnace.

[0016] In some embodiments, the gas phase extracted by negative pressure extraction is sent to a tail gas absorption tower, and the tail gas absorption tower is used to wash and recover the extracted gas phase.

[0017] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a flow chart of a method for defluorination treatment of lithium battery black powder in this application. DETAILED DESCRIPTION

[0020] "Scope" disclosed in the present application is limited in the form of lower limit and upper limit, and a given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a special range. The scope limited in this way can be including end values ​​or not including end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a scope. For example, if the scope of 60-120 and 80-110 is listed for a specific parameter, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following scope can be all expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, the numerical range "ab" represents the abbreviation of any real number combination between a and b, wherein a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0021] If there is no special explanation, the "include" and "comprising" mentioned in this application are open-ended or closed-ended. For example, the "include" and "comprising" may mean that other components not listed may also be included or only the listed components may be included or only the listed components may be included.

[0022] If not specifically stated, in this application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0023] The general inventive concept of the embodiment of the present application is to provide a method for defluorination of lithium battery black powder, by mixing the lithium battery black powder with the reaction gas and stirring evenly; then heating the stirred battery black powder mixture to the required second preset temperature and keeping it warm for reaction, so as to convert all the fluorine elements in the battery black powder mixture into hydrogen fluoride. Since hydrogen fluoride and part of the reaction gas are mixed in the gas phase, the gas phase can be extracted from the solid phase battery black powder mixture by extraction; finally, the solid phase is cooled to room temperature by filling with protective gas to obtain the defluorinated lithium battery black powder. This method can effectively remove the fluorine element in the lithium battery black powder, and provides a strong guarantee for the subsequent recycling and treatment of the lithium battery black powder. Therefore, the defluorination method for lithium battery black powder can effectively remove the fluorine element in the lithium battery black powder, which has the characteristics of simple process, low cost and good removal effect.

[0024] Based on the above general concept, reference Figure 1 As shown, the embodiment of the present application provides a method for defluorination treatment of lithium battery black powder, the method comprising the following steps:

[0025] S100, uniformly mixing lithium battery black powder and a reaction gas at a first preset temperature to obtain a battery black powder mixture, wherein the reaction gas includes at least one of water, alkanes, alkenes, alcohols, and alkyl organic acids, and the first preset temperature is 110-170° C.;

[0026] S200, heating the lithium battery black powder mixture to a second preset temperature and reacting at a constant temperature, wherein the second preset temperature is 500-800° C., and the constant temperature reaction time is 0.5-2 hours;

[0027] S300, extracting the gas phase generated by the isothermal reaction, then filling with nitrogen and cooling to room temperature to obtain defluorinated lithium battery black powder, wherein the protective gas is one of nitrogen, helium or argon.

[0028] In the embodiment of the present application, lithium battery black powder refers to the positive electrode black powder and negative electrode black powder obtained by discharging waste ternary lithium batteries or lithium iron phosphate batteries through mechanical crushing, air separation and other steps.

[0029] In the above embodiment, the first preset temperature is 110-170°C. Exemplarily, the first preset temperature can be controlled to be 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C and any value within the range of 110-170°C;

[0030] In the above embodiment, the second preset temperature is 500-800°C. Exemplarily, the second preset temperature can be controlled to be 500°C, 550°C, 600°C, 650°C, 700°C, 800°C and any value within the range of 500-800°C;

[0031] It should be noted that the protective gas may be other inert gases such as nitrogen, helium, argon, etc.;

[0032] In the above embodiment, the time of the isothermal reaction in step S200 is set to 0.5-2h. Exemplarily, the time of the isothermal reaction can be set to 0.5h, 1.0h, 1.5h, 2h and any value within the range of 0.5-2h.

[0033] In the above embodiment, the reaction gas includes at least one of water, methane, ethylene, methanol and formic acid.

[0034] In the above embodiment, the fluorine element in the lithium battery black powder can be converted into gaseous hydrogen fluoride by using high-temperature reaction gas. The gaseous hydrogen fluoride and part of the high-temperature reaction gas are mixed and extracted from the solid phase lithium battery black powder by extraction, thereby achieving the removal of fluorine element in the lithium battery black powder.

[0035] In an optional embodiment of the present application, in the step S100, the lithium battery black powder is loaded into a rotary tube furnace, filled with nitrogen to exhaust the air, and then the temperature is raised to a first preset temperature and the reaction gas is continuously introduced to exhaust the nitrogen in the rotary tube furnace and mix the reaction gas and the lithium battery black powder evenly to obtain a battery black powder mixture.

[0036] In the above embodiment, the introduction of protective gas nitrogen can exclude air in the rotary tube furnace, thereby preventing the air from adversely affecting the reaction between the reaction gas and the fluorine element in the lithium battery black powder; and the continuous introduction of the reaction gas can exclude nitrogen in the rotary tube furnace, thereby ensuring that the lithium battery black powder in the rotary tube furnace is always in the reaction gas atmosphere, further ensuring the subsequent reaction between the reaction gas and the fluoride ions in the lithium battery black powder, and at the same time, based on the rotation of the rotary tube furnace, the lithium battery black powder and the reaction gas at the first preset temperature can be evenly mixed, which is beneficial to the sufficient reaction conversion of the fluoride ions in the subsequent constant temperature reaction.

[0037] In an optional embodiment of the present application, the step S300 is specifically as follows: closing the reaction gas and extracting the gas phase generated by the isothermal reaction, then filling with protective gas nitrogen and cooling to room temperature at a cooling rate of 4-10°C / min, opening the rotary tube furnace, and obtaining the defluorinated lithium battery black powder.

[0038] In the above embodiment, the cooling rate is set to 4-10°C / min. Exemplarily, the cooling rate can be controlled to 4°C / min, 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min, 10°C / min, and any value within the range of 4-10°C / min.

[0039] In an optional embodiment of the present application, the gas phase in the rotary tube furnace is extracted by negative pressure extraction.

[0040] In an optional implementation of the present application, the gas phase extracted by negative pressure extraction is sent to a tail gas absorption tower, and the tail gas absorption tower is used to wash and recover the extracted gas phase.

[0041] In the above embodiment, the gas phase is extracted from the rotary tube furnace by negative pressure extraction, and the extracted gas phase is washed with water through a tail gas absorption tower, and finally the washed product is recovered and processed. On the one hand, it can avoid environmental pollution, and on the other hand, it further improves the economic benefits.

[0042] The following examples describe the contents disclosed in this application in more detail. These examples are for illustrative purposes only, as various modifications and variations within the scope of the contents disclosed in this application are obvious to those skilled in the art. Unless otherwise stated, all reagents and raw materials used in the examples are commercially available or synthesized according to conventional methods, and the instruments and equipment used in the examples are commercially available;

[0043] It should be noted that in the following embodiments, the reaction gas includes at least one of water, alkanes, alkenes, alcohols, and alkyl organic acids. Specifically, the alkane in the reaction gas is methane, the olefin is ethylene, the alcohol is methanol, and the alkyl organic acid is formic acid.

[0044] Example 1

[0045] 200g of lithium battery black powder with a fluorine content of 2.680% was placed in a rotary tube furnace, nitrogen was introduced to remove air, the temperature was raised to 110°C, the reaction gas was introduced to remove nitrogen, the temperature was continued to rise to 500°C, the reaction gas was continuously introduced, and the temperature was kept for 2 hours. The reaction gas was turned off and the gas phase was extracted, and then nitrogen was introduced and cooled to room temperature at a cooling rate of 4°C per minute, and the furnace cover was opened to take out the defluorinated lithium battery black powder.

[0046] Example 2

[0047] 200g of lithium battery black powder with a fluorine content of 2.680% was loaded into a rotary tube furnace, nitrogen was introduced to exclude air, the temperature was raised to 140°C and the reaction gas was introduced to exclude nitrogen, the temperature was continued to be raised to 700°C, the reaction gas was continuously introduced, and the temperature was kept for 1 hour. The reaction gas was turned off and the gas phase was extracted, and then nitrogen was introduced and cooled to room temperature at a cooling rate of 5°C per minute. The furnace cover was opened to take out the defluorinated lithium battery black powder.

[0048] Example 3

[0049] 200g of lithium battery black powder with a fluorine content of 2.680% was placed in a rotary tube furnace, nitrogen was introduced to remove air, the temperature was raised to 170°C, reaction gas was introduced to remove nitrogen, the temperature was continued to rise to 800°C, reaction gas was continuously introduced, and the temperature was kept for 0.5 hours. The reaction gas was turned off and the gas phase was extracted, and then nitrogen was introduced and cooled to room temperature at a cooling rate of 5°C per minute. The furnace cover was opened to take out the defluorinated lithium battery black powder.

[0050] The fluorine content of the lithium battery black powder raw material and the lithium battery black powder after defluorination in Example 1-3 were tested respectively. The test results are shown in Table 1.

[0051] Table 1 Detection results of fluorine content in lithium battery black powder after defluorination and lithium battery black powder raw materials in Examples 1-3

[0052]

[0053] It can be seen from Table 1 that compared with the lithium battery black powder raw material, the fluorine content in the lithium battery black powder after defluorination obtained by the defluorination treatment method provided in the present application is much lower than the fluorine content in the lithium battery black powder raw material, and the defluorination rate is above 97.5%, and even as high as 98.3%. Therefore, the lithium battery black powder defluorination treatment method provided in the present application can effectively remove the fluorine element in the battery black powder, and provides favorable conditions for the subsequent recovery and treatment of the lithium battery black powder.

[0054] The above is a detailed introduction to a method for defluorination treatment of lithium battery black powder provided by the present application. This article uses specific examples to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the core idea of ​​the present application. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. A method for defluorination treatment of lithium battery black powder, characterized in that: The method comprises the following steps: S100, uniformly mixing the lithium battery black powder and the reaction gas at a first preset temperature to obtain a battery black powder mixture, wherein the reaction gas includes at least one of alkanes, alkenes, alcohols, and alkyl organic acids, and the first preset temperature is 110-170° C. Specifically, the lithium battery black powder is loaded into a rotary tube furnace, filled with protective gas to exhaust air, and then the temperature is raised to the first preset temperature, and the reaction gas is continuously introduced to exhaust the protective gas in the rotary tube furnace, and the reaction gas and the lithium battery black powder are uniformly mixed to obtain a battery black powder mixture; S200, heating the battery black powder mixture to a second preset temperature and reacting at a constant temperature, wherein the second preset temperature is 650-800° C., and the constant temperature reaction time is 0.5-2 hours; S300, extracting the gas phase generated by the isothermal reaction, then filling it with a protective gas and cooling it to room temperature, so as to obtain the defluorinated lithium battery black powder, wherein the protective gas is one of nitrogen, helium or argon.

2. The method for defluorination treatment of lithium battery black powder according to claim 1, characterized in that: The reaction gas includes at least one of methane, ethylene, methanol and formic acid.

3. The method for defluorination treatment of lithium battery black powder according to claim 2, characterized in that: The step S300 specifically includes: closing the reaction gas and extracting the gas phase generated by the isothermal reaction, then filling with protective gas and cooling to room temperature at a cooling rate of 4-10°C / min, and opening the rotary tube furnace to obtain the defluorinated lithium battery black powder.

4. The method for defluorination of lithium battery black powder according to claim 3, characterized in that: The gas phase in the rotary tube furnace is extracted by negative pressure extraction.

5. The method for defluorination treatment of lithium battery black powder according to claim 4, characterized in that: The gas phase extracted by the negative pressure extraction method is sent to the tail gas absorption tower, and the tail gas absorption tower is used to wash and recover the extracted gas phase.

Images