Method for efficiently extracting lithium from lithium-containing mother liquor in lithium battery wet recovery process

Abstract

The invention relates to the technical field of lithium battery recovery, in particular to a method for efficiently extracting lithium from lithium-containing mother liquor in a lithium battery wet recovery process, which comprises the following extraction steps: S1, preparing a waste lithium battery to be extracted, discharging the waste lithium battery, and discharging the electric quantity in the lithium battery; s2, the lithium battery is disassembled, an internal battery material is disassembled, and the disassembled battery material is crushed; and S3, taking out a part of the crushed battery material as a sample, placing the sample in a percentage electrolyte solution, sampling, and measuring the content of lithium in the battery material. According to the method, the sample of the lithium battery material is extracted, the content of the lithium ions in the sample is measured in advance, the content of the required hydrochloric acid is calculated through calculation, and proper preparation is carried out, so that lithium in the lithium battery can be effectively extracted and recycled, the use amount of the hydrochloric acid is reduced, the pollutant emission amount is reduced, the extraction efficiency of the lithium ions is improved, and the method is suitable for large-scale popularization and application. And the waste of lithium battery resources is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium battery recycling, and specifically relates to a method for efficiently extracting lithium from lithium-containing mother liquor in a lithium battery wet recycling process. Background Art

[0002] Wet recycling of lithium batteries is a recycling method based on chemical leaching and separation processes. It is mainly used to extract valuable metal elements, such as lithium, cobalt, nickel, etc., from waste lithium batteries. The processing flow includes pretreatment, crushing and screening of lithium batteries, chemical leaching, purification and impurity removal, metal extraction and product preparation to extract metal elements from lithium batteries. When extracting lithium from lithium batteries, in the prior art, the amount of lithium extracted from lithium batteries is low, the extraction efficiency is low, and there is a lot of lithium in the lithium battery that has not been completely extracted, resulting in a waste of recycling resources. The amount of hydrochloric acid used is large, and the pollution emissions caused are also very large. In this regard, we proposed a method for efficiently extracting lithium from lithium mother liquor in a lithium battery wet recycling process. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention provides a method for efficiently extracting lithium from lithium-containing mother liquor in a lithium battery wet recovery process to solve the above technical problems.

[0004] To achieve the above object, the present invention provides the following technical solution: a method for efficiently extracting lithium from lithium-containing mother liquor in a lithium battery wet recovery process, wherein the extraction steps are as follows:

[0005] S1. Prepare the waste lithium batteries to be extracted, discharge the waste lithium batteries, and discharge all the electricity inside the lithium batteries;

[0006] S2. Disassemble the lithium battery, remove the internal battery materials, and crush the removed battery materials;

[0007] S3, taking out some of the broken battery materials as samples, placing them in a percentage electrolyte solution, sampling, and measuring the lithium content in the battery materials;

[0008] S4. According to the measured lithium content, the proportion of hydrochloric acid in the hydrochloric acid solution is adjusted. During the crushing process, the hydrochloric acid solution is poured into the crusher to react with the crushed battery material;

[0009] S5, pouring out the leachate after the reaction, adding a precipitant and an adsorbent to the stirred leachate to precipitate impurities to separate the impurities from the lithium ions;

[0010] S6, pouring sodium carbonate solution into the lithium ions in the leaching solution to react and generate lithium carbonate precipitate to extract lithium;

[0011] S7. Wash and dry the extracted lithium carbonate to remove impurities, thereby completing the extraction of lithium.

[0012] Preferably, the lithium battery discharge step in step S1 is performed by setting the discharge current, setting the discharge termination voltage, connecting the lithium battery to the discharge device, ensuring that the connection is firm, starting the discharge device for discharge processing, and monitoring the discharge status of the lithium battery in real time. When the battery voltage drops to the set termination voltage, the discharge ends, the lithium battery is disconnected, and the discharge process is completed.

[0013] Preferably, in step S2, the battery is disassembled by removing the battery box, disconnecting the battery connection line and taking out the battery, and the disassembled battery material is placed in a crusher for crushing, and the crushing time of the crusher is 1 hour. In step S3, after the crusher is crushed for 40 minutes, a partially crushed battery material sample is obtained inside the crusher.

[0014] Preferably, the ratio of the battery material sample to the electrolyte obtained in step S3 is 1:5, and the method for measuring the lithium content is measured by a constant current electrochemical method. The measuring step is performed by placing the sample in the electrolyte to form a mixed solution, inserting the electrode into the solution, converting lithium ions into electrons through electrode reaction, and measuring the current and potential to form a current standard curve graph, and calculating the lithium ion content in the sample based on the recorded data, and then calculating the lithium ion content in the overall battery material through extrapolation.

[0015] Preferably, in step S4, the proportion of hydrochloric acid used is adjusted according to the calculated lithium ion content, and the calculation step is:

[0016] Determine the mass number of lithium ions in the solution. The molar number of lithium ions is n(Li + );

[0017] Lithium ions exist entirely in the form of lithium chloride, so the number of moles of lithium chloride is equal to the number of moles of lithium ions, that is, n(LiCl)=n(Li + );

[0018] In lithium chloride, each lithium ion is combined with a chloride ion, and hydrochloric acid will dissociate into a hydrogen ion and a chloride ion in the solution. In order to obtain moles of chloride ions with lithium ions, moles of hydrogen chloride are required, that is, n(HCl) = n(LiCl) = n(Li + );

[0019] Calculate the volume of concentrated hydrochloric acid required using the formula:

[0020]

[0021] Where V is the volume of concentrated hydrochloric acid, n(HCl) is hydrogen chloride, and C is the molar concentration of concentrated hydrochloric acid;

[0022] Then dilute the concentrated hydrochloric acid to obtain the required hydrochloric acid.

[0023] Preferably, in step S4, after crushing for 45 minutes, pour the prepared hydrochloric acid solution into the crusher for stirring reaction, and wait for the stirring reaction to be completed; in step S5, after stirring for 1 hour, pour out the mixed lithium battery and the leachate together, perform preliminary filtration, filter the discarded impurities, obtain the leachate containing lithium ions, and continuously stir the leachate for 40 minutes. After stirring for 25 minutes, add a precipitant and an adsorbent to the leachate for continuous stirring. After the stirring is completed, wait for precipitation to allow the impurities and lithium ions to be further separated.

[0024] Preferably, the reaction time in step S6 is 20 min.

[0025] Preferably, in step S7, the lithium carbonate is washed by adding lithium carbonate into deionized water and soaking the lithium carbonate for 2 hours. After the soaking is completed, the lithium carbonate is taken out and dried.

[0026] Preferably, the drying step in step S7 is performed by placing the lithium carbonate in a dryer for heating and drying, and the drying temperature is 30°C.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present application extracts samples of lithium battery materials, measures the lithium ion content in the samples in advance, and then calculates the required hydrochloric acid content and configures it in appropriate amounts. It can effectively extract and recover lithium from lithium batteries, reduce the amount of hydrochloric acid used, reduce the amount of pollution emissions, improve the extraction efficiency of lithium ions, and reduce the waste of lithium battery resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The figure is a flowchart of the lithium extraction steps of the present invention. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] The present invention provides a technical solution: a method for efficiently extracting lithium from lithium-containing mother liquor in a lithium battery wet recovery process, wherein the extraction steps are as follows:

[0032] S1. Prepare the waste lithium batteries to be extracted, discharge the waste lithium batteries, and discharge all the electricity inside the lithium batteries;

[0033] S2. Disassemble the lithium battery, remove the internal battery materials, and crush the removed battery materials;

[0034] S3, taking out some of the broken battery materials as samples, placing them in a percentage electrolyte solution, sampling, and measuring the lithium content in the battery materials;

[0035] S4. According to the measured lithium content, the proportion of hydrochloric acid in the hydrochloric acid solution is adjusted. During the crushing process, the hydrochloric acid solution is poured into the crusher to react with the crushed battery material;

[0036] S5, pouring out the leachate after the reaction, adding a precipitant and an adsorbent to the stirred leachate to precipitate impurities to separate the impurities from the lithium ions;

[0037] S6, pouring sodium carbonate solution into the lithium ions in the leaching solution to react and generate lithium carbonate precipitate to extract lithium;

[0038] S7, washing and drying the extracted lithium carbonate to remove impurities contained therein, thereby completing the extraction of lithium;

[0039] It can effectively extract and recycle lithium from lithium batteries, reduce the amount of hydrochloric acid used, reduce the amount of pollution emissions, improve the extraction efficiency of lithium ions, and reduce the waste of lithium battery resources.

[0040] Furthermore, in step S1, the lithium battery discharge step sets the discharge current, sets the discharge termination voltage, connects the lithium battery to the discharge device, ensures that the connection is stable, starts the discharge device to perform the discharge process, and monitors the discharge state of the lithium battery in real time. When the battery voltage drops to the set termination voltage, the discharge ends, the lithium battery is disconnected, and the discharge process is completed.

[0041] During the entire discharge process, be sure to ensure safe operation to prevent accidents such as short circuits and leakage. Pay close attention to changes in parameters such as voltage and current during the discharge process, and adjust the discharge conditions in a timely manner to avoid complete depletion of the battery power to extend the battery life. The discharge treatment of waste lithium batteries should follow environmental protection principles.

[0042] Furthermore, in step S2, the battery can be disassembled by removing the battery box, disconnecting the battery connection line and taking out the battery, and the disassembled battery material is placed in a crusher for crushing, and the crushing time of the crusher is 1 hour. In step S3, after the crusher is crushed for 40 minutes, a partially crushed battery material sample is obtained inside the crusher.

[0043] Furthermore, the ratio of the battery material sample to the electrolyte obtained in step S3 is 1:5, and the method for measuring the lithium content is measured by a constant current electrochemical method. The measuring step is to place the sample in the electrolyte to form a mixed solution, insert the electrode into the solution, convert the lithium ions into electrons through the electrode reaction, and measure the current and potential to form a current standard curve graph, calculate the lithium ion content in the sample based on the recorded data, and then calculate the lithium ion content in the overall battery material through extrapolation;

[0044] The principle is that under a specific potential, the solution to be tested is used as the electrolyte, and the lithium ion content is determined by measuring the current change. In the electrochemical system, when a constant current is applied to the electrode, an electrochemical reaction will occur on the electrode surface, resulting in a change in the electrode potential. This potential change is closely related to factors such as the properties of the electrode material, the type of electrolyte, and the reaction conditions. By measuring and recording these potential changes, we can gain an in-depth understanding of the kinetics of the electrochemical reaction, the reaction mechanism, and the performance of the electrode material; the measurement results are accurate and reliable, and are applicable to solutions and solid samples.

[0045] Furthermore, in step S4, the proportion of hydrochloric acid used is adjusted according to the calculated lithium ion content, and the calculation steps are as follows:

[0046] Determine the mass number of lithium ions in the solution. The molar number of lithium ions is n(Li + );

[0047] Lithium ions exist entirely in the form of lithium chloride, so the number of moles of lithium chloride is equal to the number of moles of lithium ions, that is, n(LiCl)=n(Li + );

[0048] In lithium chloride, each lithium ion is combined with a chloride ion, and hydrochloric acid will dissociate into a hydrogen ion and a chloride ion in the solution. In order to obtain moles of chloride ions with lithium ions, moles of hydrogen chloride are required, that is, n(HCl) = n(LiCl) = n(Li + );

[0049] Calculate the volume of concentrated hydrochloric acid required using the formula:

[0050]

[0051] Where V is the volume of concentrated hydrochloric acid, n(HCl) is hydrogen chloride, and C is the molar concentration of concentrated hydrochloric acid;

[0052] Then dilute the concentrated hydrochloric acid to obtain the required hydrochloric acid;

[0053] According to the signal intensity of the sample to be tested, the corresponding concentration value is found on the standard curve. If the standard curve is linear, it can be obtained by simple interpolation calculation.

[0054] Further, in step S4, after crushing for 45 minutes, pour the prepared hydrochloric acid solution into the crusher for stirring reaction, and wait for the stirring reaction to be completed; in step S5, after stirring for 1 hour, pour out the mixed lithium battery and the leachate together, perform preliminary filtration, filter the discarded impurities, obtain the leachate containing lithium ions, and stir the leachate continuously for 40 minutes. After stirring for 25 minutes, add the precipitant and the adsorbent to the leachate for continuous stirring. After the stirring is completed, wait for precipitation to allow the impurities and lithium ions to be further separated;

[0055] The benefits of crushing and leaching are:

[0056] After the lithium battery is crushed, the surface area of ​​the material particles increases, making the contact between hydrochloric acid and the material more complete, thereby improving the leaching efficiency. The crushing process helps to reduce the mass transfer resistance inside the material, allowing hydrochloric acid to penetrate into the material faster and react with more active substances;

[0057] The crushed material has a higher specific surface area, which is conducive to the rapid exchange of hydrochloric acid with the reactants on the surface of the material, thereby accelerating the reaction rate;

[0058] The leaching reaction of crushed lithium battery materials in hydrochloric acid is easier to carry out because the reduction in particle size reduces the diffusion distance, making it easier for reactants to approach and react.

[0059] Furthermore, the reaction time in step S6 is 20 min.

[0060] Furthermore, in step S7, the lithium carbonate is washed by adding lithium carbonate into deionized water and soaking the lithium carbonate for 2 hours. After the soaking is completed, the lithium carbonate is taken out and dried.

[0061] Deionized water is achieved through ion exchange resin technology. The cation exchange resin absorbs cations in the water and releases hydrogen ions (H+). The water containing hydrogen ions then passes through the anion exchange resin. The resin absorbs anions in the water and releases hydroxide ions (OH-). The hydrogen ions combine with the hydroxide ions to form water, thereby removing ionic impurities in the water.

[0062] Furthermore, in step S7, the drying step is performed by placing the lithium carbonate in a dryer for heating and drying, and the drying temperature is 30° C.;

[0063] The working principle of the dryer is mainly based on the transfer of heat energy and the vaporization of moisture. During the drying process, heat is transferred from the high-temperature heat source to the wet material in various ways, causing the moisture on the surface of the material to vaporize and dissipate to the external space. At the same time, the moisture inside the material is transferred to the surface through diffusion and continues to vaporize until the material reaches the specified moisture content.

[0064] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0065] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for efficiently extracting lithium from lithium-containing mother liquor in a lithium battery wet recovery process, characterized in that: The extraction steps are: S1. Prepare the waste lithium batteries to be extracted, discharge the waste lithium batteries, and discharge the electricity inside the lithium batteries; S2. Disassemble the lithium battery, remove the internal battery materials, and crush the removed battery materials; S3, taking out some of the broken battery materials as samples, placing them in a percentage electrolyte solution, sampling, and measuring the lithium content in the battery materials; S4. According to the measured lithium content, the proportion of hydrochloric acid in the hydrochloric acid solution is adjusted. During the crushing process, the hydrochloric acid solution is poured into the crusher to react with the crushed battery material; S5, pouring out the leachate after the reaction, adding a precipitant and an adsorbent to the stirred leachate to precipitate impurities to separate the impurities from the lithium ions; S6, pouring sodium carbonate solution into the lithium ions in the leaching solution to react and generate lithium carbonate precipitate to extract lithium; S7. Wash and dry the extracted lithium carbonate to remove impurities, thereby completing the extraction of lithium.

2. The method for efficiently extracting lithium from lithium-containing mother liquor in a lithium battery wet recovery process according to claim 1, characterized in that: In step S1, the lithium battery discharge step sets the discharge current, sets the discharge termination voltage, connects the lithium battery to the discharge device, ensures that the connection is firm, starts the discharge device for discharge processing, and monitors the lithium battery discharge status in real time. When the battery voltage drops to the set termination voltage, the discharge ends, the lithium battery is disconnected, and the discharge process is completed.

3. The method for efficiently extracting lithium from lithium-containing mother liquor in a lithium battery wet recovery process according to claim 1, characterized in that: In step S2, the battery is disassembled by removing the battery box, disconnecting the battery connection line and taking out the battery, and the disassembled battery material is placed in a crusher for crushing. The crushing time of the crusher is 1 hour. In step S3, after the crusher is crushed for 40 minutes, a partially crushed battery material sample is obtained inside the crusher.

4. The method for efficiently extracting lithium from lithium-containing mother liquor in a lithium battery wet recovery process according to claim 1, characterized in that: The ratio of the battery material sample to the electrolyte obtained in step S3 is 1:

5. The method for measuring the lithium content is measured by a constant current electrochemical method. The measuring step is to place the sample in the electrolyte to form a mixed solution, insert the electrode into the solution, convert the lithium ions into electrons through the electrode reaction, and measure the current and potential to form a current standard curve graph. The lithium ion content in the sample is calculated based on the recorded data, and then the lithium ion content in the entire battery material is calculated through extrapolation.

5. The method for efficiently extracting lithium from lithium-containing mother liquor in a lithium battery wet recovery process according to claim 1, characterized in that: In step S4, the proportion of hydrochloric acid used is adjusted according to the calculated lithium ion content. The calculation steps are as follows: Determine the mass number of lithium ions in the solution. The molar number of lithium ions is n(Li + ); Lithium ions exist entirely in the form of lithium chloride, so the number of moles of lithium chloride is equal to the number of moles of lithium ions, that is, n(LiCl)=n(Li + ); In lithium chloride, each lithium ion is combined with a chloride ion, and hydrochloric acid will dissociate into a hydrogen ion and a chloride ion in the solution. In order to obtain moles of chloride ions with lithium ions, moles of hydrogen chloride are required, that is, n(HCl) = n(LiCl) = n(Li + ); Calculate the volume of concentrated hydrochloric acid required using the formula: Where V is the volume of concentrated hydrochloric acid, n(HCl) is hydrogen chloride, and C is the molar concentration of concentrated hydrochloric acid; Then dilute the concentrated hydrochloric acid to obtain the required hydrochloric acid.

6. The method for efficiently extracting lithium from lithium-containing mother liquor in a lithium battery wet recovery process according to claim 1, characterized in that: In step S4, after crushing for 45 minutes, pour the prepared hydrochloric acid solution into the crusher for stirring reaction, and wait for the stirring reaction to be completed; in step S5, after stirring for 1 hour, pour out the mixed lithium battery and the leachate together, perform preliminary filtration, filter the discarded impurities, obtain the leachate containing lithium ions, and stir the leachate continuously for 40 minutes. After stirring for 25 minutes, add the precipitant and the adsorbent to the leachate for continuous stirring. After the stirring is completed, wait for precipitation to allow the impurities and lithium ions to be further separated.

7. The method for efficiently extracting lithium from lithium-containing mother liquor in a lithium battery wet recovery process according to claim 1, characterized in that: The reaction time in step S6 is 20 min.

8. The method for efficiently extracting lithium from lithium-containing mother liquor in a lithium battery wet recovery process according to claim 1, characterized in that: In step S7, the lithium carbonate is washed by adding lithium carbonate into deionized water and soaking the lithium carbonate for 2 hours. After the soaking is completed, the lithium carbonate is taken out and dried.

9. The method for efficiently extracting lithium from lithium-containing mother liquor in a lithium battery wet recovery process according to claim 1, characterized in that: In the drying step of step S7, the lithium carbonate is placed in a dryer for heating and drying, and the drying temperature is 30°C.

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