System and method for recovering sodium carbonate in lithium precipitation mother liquor
By performing solid-liquid separation and soda ash concentration management on lithium precipitation mother liquor, the problems of resource waste and high cost in lithium precipitation mother liquor treatment were solved, and the efficient recovery and reuse of soda ash were achieved, reducing production costs.
Patent Information
- Application Number
- CN202511931987.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-19
- Publication Date
- 2026-04-21
AI Technical Summary
In existing technologies, the treatment of lithium precipitation mother liquor mainly leads to the waste of water resources and valuable chemicals, and the high alkalinity treatment is costly and cannot effectively recycle soda ash.
By performing solid-liquid separation on the lithium precipitation mother liquor, the current and target concentrations of soda ash are determined. The target amount of soda ash is then calculated and added to the clarified mother liquor to form a soda ash solution of the target concentration, which is then used in subsequent processes to achieve the reuse and recycling of soda ash.
This effectively reduces the cost of using soda ash, avoids resource waste and high-cost acid neutralization treatment, and enables precise recovery and reuse of soda ash.
Smart Images
Figure CN121894684A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of lithium battery recycling technology, and in particular to a system and method for recovering soda ash from lithium precipitation mother liquor. Background Technology
[0002] In the industrial production of lithium salts such as lithium carbonate, soda ash is typically used as a precipitant, reacting with a lithium-containing solution to produce lithium carbonate. After the reaction is complete, solid-liquid separation yields the lithium salt product and the lithium precipitation mother liquor. The lithium precipitation mother liquor usually contains excess sodium carbonate, byproducts such as sodium sulfate or sodium hydroxide, and a small amount of incompletely precipitated lithium ions.
[0003] Currently, there are two main ways to treat lithium precipitation mother liquor: one is to discharge it directly or after treatment, which not only wastes water resources and valuable chemicals, but also increases the environmental burden and wastewater treatment costs; the other is to carry out complex recycling treatment. Because lithium precipitation mother liquor contains high residual alkalinity, direct treatment requires a large amount of acid for neutralization, which is costly.
[0004] The above content is only used to help understand the technical solution of this application and does not represent an admission that the above content is prior art. Summary of the Invention
[0005] The main objective of this application is to provide a system and method for recovering soda ash from lithium precipitation mother liquor, aiming to reduce the cost of using soda ash in the lithium precipitation process by recovering and reusing soda ash from lithium precipitation mother liquor.
[0006] To achieve the above objectives, this application proposes a method for recovering soda ash from lithium precipitation mother liquor, the method comprising: A lithium precipitation mother liquor is provided, and the lithium precipitation mother liquor is subjected to solid-liquid separation to obtain a clarified mother liquor; Determine the current concentration of soda ash in the clarified mother liquor; Based on the target process for soda ash recycling, the target concentration of the soda ash is determined; Based on the current concentration of the soda ash and the target concentration of the soda ash, determine the target amount of soda ash to be added; The pre-added soda ash is added to the clarified mother liquor according to the target addition amount to form a soda ash solution with the target concentration, and then reused in the target process.
[0007] In one feasible implementation, the target process includes an extraction saponification process and / or a leaching impurity removal process.
[0008] In one feasible implementation, when the target process is the leaching and impurity removal process, after the soda ash with the target concentration is recycled to the target process, the solution pH of the leaching and impurity removal process is 4-5.
[0009] In one feasible implementation, the target concentration during the extraction and saponification process is calculated based on the reaction process of the pre-used extractant and the soda ash.
[0010] In one feasible implementation, the step of determining the target amount of soda ash to be added based on the current concentration of the soda ash and the target concentration of the soda ash includes: Determine the purity of the pre-added soda ash; The target amount of soda ash is determined based on the target concentration and the solution volume of the target process. Calculate the current amount of soda ash based on the volume of the clarified mother liquor and the current concentration of soda ash in the clarified mother liquor; The target amount of soda ash to be added is determined based on the target amount of soda ash, the current amount of soda ash, and the purity of the soda ash to be added.
[0011] In one feasible implementation, the current concentration of soda ash in the clarified mother liquor is determined by titration.
[0012] In one feasible implementation, the solid-liquid separation is performed by filtration and / or centrifugation.
[0013] This application also provides a system for recovering soda ash from lithium precipitation mother liquor, using the method for recovering soda ash from lithium precipitation mother liquor as described above. The system includes: The pretreatment module is used to collect lithium precipitation mother liquor and perform solid-liquid separation to obtain clarified mother liquor; The component analysis module, connected to the pretreatment module, is used to analyze the current concentration of soda ash in the clarified mother liquor; The calculation module, connected to the component analysis module, is used to determine the target amount of soda ash to be added. A configuration module, connected to the pretreatment module and the calculation module, is used to add pre-added soda ash to the clarified mother liquor according to the target addition amount, and stir and mix to prepare a soda ash solution with the target concentration. The reuse conveying module is connected to the configuration module and is used to convey the configured soda ash solution with the target concentration to the target process.
[0014] In one feasible implementation, the configuration module includes a mixing tank and a mechanical stirrer disposed within the mixing tank.
[0015] In one feasible implementation, the component analysis module is further used to detect metal elements in the lithium precipitation mother liquor, so as to recycle the metal elements in the lithium precipitation mother liquor.
[0016] The present application proposes one or more technical solutions, which have at least the following technical effects: providing lithium precipitation mother liquor; performing solid-liquid separation on the lithium precipitation mother liquor to obtain clarified mother liquor; removing solid impurities from the lithium precipitation mother liquor through solid-liquid separation; obtaining clarified mother liquor to support subsequent determination and calculation of soda ash usage; determining the current concentration of soda ash in the clarified mother liquor; accurately obtaining the current concentration of soda ash is the basis for subsequent calculations; determining the target concentration of soda ash based on the target process of soda ash recycling; determining the target amount of soda ash to be added based on the current concentration and the target concentration of soda ash, avoiding the need to consume a large amount of soda ash to reconfigure the soda ash to meet the target concentration of the target process, effectively reducing the cost of soda ash usage; adding pre-added soda ash to the clarified mother liquor according to the target amount to form a soda ash solution with the target concentration, and recycling it to the target process, avoiding the waste of resources caused by the direct discharge of traditional lithium precipitation mother liquor, as well as the high cost of using a large amount of acid for treatment; and achieving full recovery and reuse of soda ash after accurate calculation of the soda ash in the lithium precipitation mother liquor. The present application reduces the cost of soda ash usage in the lithium precipitation process by recovering and reusing soda ash from the lithium precipitation mother liquor. Attached Figure Description
[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.
[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0019] Figure 1 A schematic flowchart illustrating an embodiment of the method for recovering soda ash from lithium precipitation mother liquor in this application; Figure 2 This is a schematic diagram of the structure of the soda ash recovery system provided in the embodiment of the lithium precipitation mother liquor of this application.
[0020] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation
[0021] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.
[0022] The following detailed description, with appropriate reference to the accompanying drawings, discloses embodiments of the soda ash recovery system and method for lithium precipitation mother liquor of this application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided for the purpose of enabling those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.
[0023] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for a specific parameter, it is also expected that ranges of 60~110 and 80~120 are also included. Furthermore, if minimum range values of 1 and 2 are listed, and if maximum range values of 3, 4, and 5 are listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this application, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.
[0024] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.
[0025] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.
[0026] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.
[0027] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.
[0028] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: 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).
[0029] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the technical solution of this application is further described below in conjunction with the accompanying drawings and embodiments. However, this application is not limited to the listed embodiments, but should also include any other well-known modifications within the scope of the claims made in this application.
[0030] The term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of this application. The phrase "in one embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.
[0031] Currently, there are two main ways to treat lithium precipitation mother liquor: one is to discharge it directly or after treatment, which not only wastes water resources and valuable chemicals, but also increases the environmental burden and wastewater treatment costs; the other is to carry out complex recycling treatment. Because lithium precipitation mother liquor contains high residual alkalinity, direct treatment requires a large amount of acid for neutralization, which is costly.
[0032] This application provides a lithium precipitation mother liquor, which undergoes solid-liquid separation to obtain a clarified mother liquor. Solid impurities are removed from the mother liquor through solid-liquid separation, providing a clarified mother liquor to support subsequent determination and calculation of soda ash usage. The current concentration of soda ash in the clarified mother liquor is determined, as this is crucial for subsequent calculations. Based on the target process for soda ash reuse, a target concentration of soda ash is determined. Based on the current and target concentrations, a target amount of soda ash is determined, avoiding the need for large quantities of soda ash to be reconfigured to meet the target concentration of the target process, effectively reducing the cost of soda ash usage. The pre-added soda ash is added to the clarified mother liquor according to the target amount to form a soda ash solution with the target concentration, which is then reused in the target process. This avoids the waste of resources caused by direct discharge of traditional lithium precipitation mother liquor and the high cost of treating it with large amounts of acid. Accurate calculation of the soda ash in the lithium precipitation mother liquor enables full recovery and reuse. This application reduces the cost of soda ash usage in the lithium precipitation process by recovering and reusing soda ash from the lithium precipitation mother liquor.
[0033] To better understand the technical solution of this application, a detailed description will be provided below in conjunction with the accompanying drawings and specific implementation methods.
[0034] Based on this, embodiments of this application provide a method for recovering soda ash from lithium precipitation mother liquor, referring to... Figure 1 The methods include: Step S10: Provide lithium precipitation mother liquor, perform solid-liquid separation on the lithium precipitation mother liquor to obtain clarified mother liquor; In one feasible embodiment, the lithium precipitation mother liquor is collected from the lithium salt production line, and solid-liquid separation is performed on the lithium precipitation mother liquor to remove a small amount of solid insoluble matter caused by entrainment or crystallization, so as to obtain a clear mother liquor.
[0035] Alternatively, lithium precipitation typically involves adding a precipitant (such as soda ash-sodium carbonate) to a lithium-containing solution, causing lithium ions to precipitate out as lithium salts such as lithium carbonate. After the precipitation reaction, solid-liquid separation yields lithium salt products such as lithium carbonate, while the remaining solution containing various impurity ions and incompletely precipitated lithium is the lithium precipitation mother liquor.
[0036] Optionally, in order to ensure complete precipitation of lithium ions into lithium carbonate during the lithium precipitation process, an appropriate amount of soda ash is added. Therefore, the lithium precipitation mother liquor obtained after the lithium precipitation process will contain an excess of sodium carbonate, by-product sodium sulfate or sodium hydroxide, and a small amount of incompletely precipitated lithium ions.
[0037] Optionally, lithium precipitation mother liquor contains a certain amount of metal elements and ions related to precipitants. Direct discharge of these substances can easily cause environmental pollution and waste of resources.
[0038] Optionally, during the lithium precipitation process, some solid substances may remain in the mother liquor due to entrainment or crystallization. Entrainment refers to the process where some solid particles are encapsulated by the liquid and carried into the mother liquor during precipitation; crystallization may occur due to changes in conditions such as temperature and concentration, causing some substances to precipitate and form crystals in the mother liquor. These insoluble solids can affect the effectiveness of subsequent mother liquor treatment processes and product quality.
[0039] In one feasible implementation, solid-liquid separation methods include filtration and / or centrifugation.
[0040] Alternatively, plate and frame filtration, vacuum filtration, or other methods can be used. Plate and frame filtration uses a plate and frame filter press to trap solid particles in the mother liquor on the filter cloth through pressure, thereby achieving solid-liquid separation. Vacuum filtration, on the other hand, creates a vacuum on one side of the filter medium, allowing the mother liquor to pass through the filter medium under the action of pressure difference, while solid particles are trapped.
[0041] Alternatively, centrifugal force generated by the high-speed rotation of a centrifuge can be used to separate solid particles from the liquid. Centrifugation offers fast separation speed and good separation effect, making it suitable for processing mother liquor containing fine solid particles.
[0042] Optionally, after removing insoluble solids through solid-liquid separation, the resulting clarified mother liquor is more beneficial for subsequent processing and analysis. The clarified mother liquor allows for more accurate determination of the content of various components, providing a reliable basis for further lithium recovery and impurity removal processes.
[0043] Step S20: Determine the current concentration of soda ash in the clarified mother liquor; In one feasible embodiment, the current concentration of soda ash in the obtained clarified mother liquor is determined by titration with hydrochloric acid, which is used to determine the specific amount of soda ash that can be reused.
[0044] The current concentration refers to the concentration of soda ash in the clarified mother liquor, which serves as the basis for subsequent calculations of the amount of soda ash that needs to be added.
[0045] In one feasible implementation, the current concentration of soda ash in the clarified mother liquor is determined by titration.
[0046] Titration has advantages such as relatively simple operation, low equipment cost, and accurate and reliable analytical results. It is widely used in chemical analysis and can meet the requirements for determining the concentration of soda ash in clarified mother liquor in most cases.
[0047] The clarified mother liquor is titrated with hydrochloric acid. The process of chemical reaction between hydrochloric acid of known concentration and sodium carbonate is used. A suitable indicator (such as phenolphthalein, methyl orange, etc.) is selected to indicate the titration endpoint. Based on the volume and concentration of hydrochloric acid consumed, the current concentration of soda ash in the clarified mother liquor can be calculated.
[0048] Step S30: Determine the target concentration of soda ash based on the target process of soda ash recycling; In a feasible example, accurately determining the target amount of soda ash required for the target process is crucial. Insufficient soda ash may fail to meet the requirements of the production process, leading to decreased product yield or substandard quality; while excessive soda ash will not only increase production costs but may also introduce too many impurities, affecting the stability of the production process and product quality.
[0049] The target process refers to determining the specific production stage in the process of soda ash recycling to incorporate the recycled soda ash.
[0050] The target concentration is determined based on the process requirements of the target process, and indicates the appropriate amount of soda ash that should be present in the solution during the target process.
[0051] In one feasible implementation, the target process includes an extraction saponification process and / or a leaching impurity removal process.
[0052] Alternatively, extraction is a separation method that utilizes the difference in solubility of a solute in two immiscible solvents to transfer the solute from one solvent to another. During extraction, to improve the extraction efficiency and selectivity, the extractant often needs to be saponified. Saponification refers to adding an alkaline substance (such as soda ash, i.e., sodium carbonate) to the extractant, causing some functional groups in the extractant to react with the alkali and form the corresponding salt.
[0053] In one feasible implementation, the target concentration during the extraction saponification process is calculated based on the reaction process of the pre-used soda ash.
[0054] A specific chemical reaction occurs between the extractant and soda ash. Based on the stoichiometric relationship of the chemical reaction (i.e., the molar ratio between reactants and products), combined with known information such as the initial amounts of extractant and soda ash, and reaction conditions, the amount of relevant substances after the reaction can be calculated, and thus the target concentration can be obtained.
[0055] For example, when the target process stage is extraction saponification, the amount of target soda ash can be calculated according to the following equation: 4(HA)2+2Na2CO3→4NaA·(HA)+2CO2+2H2O); HA represents the acidic extractant used in the extraction process.
[0056] For example, HA can be an organic acid or an organophosphate extractant.
[0057] Optionally, leaching for impurity removal refers to the process of dissolving the target component in a solid raw material using a suitable solvent. The raw material may contain impurities that can affect subsequent separation and purification processes. Therefore, impurity removal is necessary. Soda ash can separate impurities from the solution by adjusting the pH and reacting chemically with impurity ions, causing them to precipitate. The lithium precipitation mother liquor and the resulting clarified mother liquor contain impurity ions such as iron and aluminum. During the leaching process, soda ash can hydrolyze to generate hydroxide ions, which can cause iron and aluminum impurity ions to form hydroxide precipitates, thereby achieving the purpose of impurity removal.
[0058] In one feasible implementation, when the target process is a leaching and impurity removal process, after the soda ash with the target concentration is recycled to the target process, the pH of the solution in the leaching and impurity removal process is 4 to 5.
[0059] In one feasible embodiment, when the target process is determined to be a leaching and impurity removal process, reusing soda ash with a specific target concentration into the leaching and impurity removal process can maintain the solution pH value in the leaching and impurity removal process within a suitable range of 4 to 5.
[0060] Optionally, soda ash is a strong base-weak acid salt, which undergoes hydrolysis in aqueous solution. The hydrolysis process produces hydroxide ions, which can react with metal ions from the leaching process to form a precipitate for removal. In a pH range of 4-5, common impurity ions in the solution (such as Fe) 3+ Al 3+ (e.g., Fe(OH)3, Al(OH)3) will form hydroxide precipitates.
[0061] Step S40: Determine the target amount of soda ash to be added based on the current concentration of soda ash and the target concentration of soda ash. In one feasible embodiment, the amount of additional soda ash to be added is calculated using a material balance method, based on the current concentration of soda ash present in the clarified mother liquor and the target concentration of soda ash required for the target process.
[0062] In one feasible implementation, step S40, which determines the target amount of soda ash to be added based on the current concentration and the target concentration of soda ash, includes: Step S41: Determine the purity of the soda ash to be added; In one feasible embodiment, in actual production, the soda ash used for addition is usually not absolutely pure and may contain a certain proportion of impurities. Different purities of soda ash have different contents of the active ingredient (sodium carbonate). To accurately calculate the amount of soda ash to be added, the purity of the soda ash to be added must first be determined.
[0063] Step S42: Determine the target amount of soda ash based on the target concentration and the solution volume of the target process; In one feasible embodiment, the solution volume of the target process is a known production parameter. Based on the definition of concentration (concentration = mass of solute / volume of solution), the mass of soda ash required to achieve the target concentration, i.e., the target amount of soda ash, can be calculated using the target concentration and the solution volume.
[0064] Step S43: Calculate the current amount of soda ash based on the volume of the clarified mother liquor and the current concentration of soda ash in the clarified mother liquor; In one feasible embodiment, the volume of the collected clarified mother liquor is known. Based on the definition of concentration (concentration = mass of solute / volume of solution), the current amount of soda ash in the clarified mother liquor can be calculated using the current concentration and solution volume.
[0065] Step S44: Determine the target amount of soda ash to be added based on the target amount of soda ash, the current amount of soda ash, and the purity of the soda ash to be added.
[0066] In one feasible embodiment, a certain amount of soda ash needs to be added to achieve the target concentration in the clarified mother liquor. This added amount should compensate for the difference between the existing amount of soda ash in the mother liquor and the target amount. Simultaneously, since the pre-added soda ash has a certain purity, this factor needs to be considered in the calculation, converting the required amount of soda ash into the actual amount of impurity-containing soda ash that needs to be added.
[0067] In step S50, the pre-added soda ash is added to the clarified mother liquor according to the target addition amount to form a soda ash solution with the target concentration, which is then reused in the target process.
[0068] In one feasible embodiment, a calculated amount of soda ash is added to bring the concentration of soda ash in the clarified mother liquor to the target concentration. The treated clarified mother liquor is then reused in the target process of the production flow, allowing the recovered soda ash to continue participating in the production process, achieving resource recycling, reducing raw material consumption, and also helping to reduce the environmental impact of the production process.
[0069] For example, based on the volume V1 of the clarified mother liquor, its current concentration C1 (as Na2CO3), target concentration C2, and target volume V2, the amount M of external soda ash to be added is calculated using the formula: M=(C2×V2-C1×V1) / P, where P is the purity of the external soda ash. The calculated external soda ash is added to the lithium precipitation mother liquor and completely dissolved and mixed using mechanical stirring or other methods to obtain a soda ash solution with a concentration of the target value C2 that meets the process requirements.
[0070] This embodiment provides a lithium precipitation mother liquor, performs solid-liquid separation to obtain a clarified mother liquor, removes solid impurities from the mother liquor through solid-liquid separation, and obtains a clarified mother liquor to support subsequent determination and calculation of soda ash usage; determines the current concentration of soda ash in the clarified mother liquor, which is the basis for subsequent calculations; determines the target concentration of soda ash based on the target process of soda ash recycling; and determines the target amount of soda ash to be added based on the current concentration and the target concentration, avoiding the need to consume large amounts of soda ash to reconfigure the soda ash to meet the target concentration of the target process, effectively reducing the cost of soda ash usage; and adds the pre-added soda ash to the clarified mother liquor according to the target amount to form a soda ash solution with the target concentration, which is then recycled to the target process, avoiding the waste of resources caused by the direct discharge of traditional lithium precipitation mother liquor and the high cost of using large amounts of acid for treatment. Accurate calculation of the soda ash in the lithium precipitation mother liquor enables full recovery and reuse. This application reduces the cost of soda ash usage in the lithium precipitation process by recovering and reusing soda ash from the lithium precipitation mother liquor.
[0071] The second aspect of this application provides a system for recovering soda ash from lithium precipitation mother liquor, using the method for recovering soda ash from lithium precipitation mother liquor as described above, with reference to... Figure 2 The system includes: Pretreatment module 10 is used to collect lithium precipitation mother liquor and perform solid-liquid separation to obtain clarified mother liquor; The component analysis module 20 is connected to the pretreatment module 10 and is used to analyze the current concentration of soda ash in the clarified mother liquor; The calculation module 30 is connected to the component analysis module 20 and is used to determine the target amount of soda ash to be added. The configuration module 40 is connected to the pretreatment module 10 and the calculation module 20. It is used to add the pre-added soda ash to the clarified mother liquor according to the target addition amount and stir and mix it to prepare a soda ash solution with the target concentration. The reuse conveying module 50 is connected to the configuration module 40 and is used to convey the configured soda ash solution with the target concentration to the target process.
[0072] In one feasible embodiment, refer to Figure 2 Lithium precipitation is carried out by adding soda ash as a precipitant to a lithium-rich solution. The precipitation process includes leaching to remove impurities and extraction saponification. After a series of precipitation processes, a lithium precipitation mother liquor is obtained. The pretreatment module 10 is used to separate the solid and liquid components of the lithium precipitation mother liquor by filtration or centrifugation to obtain a clarified mother liquor. The component analysis module 20 measures the current concentration of soda ash in the clarified mother liquor; the calculation module 30 calculates the target amount of soda ash to be added based on the current concentration of soda ash in the clarified mother liquor and the target concentration of soda ash in the target process; the configuration module 40 adds the pre-added soda ash to the clarified mother liquor according to the target amount and transports it to the target process through the recycling and conveying module 50.
[0073] In one possible implementation, the configuration module includes a mixing tank and a mechanical stirrer disposed within the mixing tank.
[0074] In one feasible embodiment, a stirred tank is used to receive the clarified mother liquor and the pre-added soda ash, and a mechanical stirrer is used to uniformly mix the pre-added soda ash into the clarified mother liquor according to the target addition amount to form a soda ash solution with the target concentration. The type of stirrer and the stirring speed can be adjusted according to factors such as the size of the stirred tank and the properties of the materials to ensure the mixing effect.
[0075] In one feasible implementation, the component analysis module is also used to detect metal elements in the lithium precipitation mother liquor for the recovery and utilization of metal elements in the lithium precipitation mother liquor.
[0076] In a feasible embodiment, the component analysis module may employ various analytical techniques and equipment, such as spectroscopic analysis and chemical analysis methods, to accurately determine the content of various metal elements in the lithium precipitation mother liquor. Lithium precipitation mother liquor is a waste liquid generated during lithium salt production. Besides containing components such as soda ash, it may also contain various metal elements, such as lithium, sodium, potassium, and magnesium. On the one hand, accurately understanding the content of metal elements helps to comprehensively grasp the compositional characteristics of the lithium precipitation mother liquor, providing basic data for subsequent treatment and recycling. On the other hand, the different contents of different metal elements result in varying recovery value and difficulty. By detecting the amount of metal elements, the feasibility and potential benefits of recycling can be assessed, providing a basis for formulating a reasonable recycling strategy.
[0077] For example, the lithium ion concentration in the clarified mother liquor can be detected, and further recovery of lithium ions can be achieved during the process of recycling to lithium precipitation, effectively improving the lithium ion recovery rate.
[0078] To enable those skilled in the art to clearly understand the details and operations of the above embodiments of this application, and to demonstrate the significant improvement in the performance of the lithium metal battery recycling method of this application, the above technical solutions are illustrated below through multiple embodiments.
[0079] Example 1 After pretreatment, the lithium precipitation mother liquor was clarified and collected at a depth of 10 m. 3 The clarified mother liquor. Titration analysis shows the current concentration of soda ash in the lithium precipitation mother liquor is 45 g / L. A target concentration of 200 g / L of soda ash is needed for pH adjustment in the leaching and impurity removal process. Industrial soda ash with a purity of 98% will be used for replenishment. The amount M of soda ash to be added is calculated using the following process: The current amount of soda ash = 45 g / L × 10000 L = 450000 g; The target amount of soda ash = 200 g / L × 10000 L = 2000000 g; The target amount of soda ash added = (2,000,000 g - 450,000 g) / 98% ≈ 1,582 kg.
[0080] 10 m 3 Add approximately 1582 kg of 98% industrial soda ash to the clarified mother liquor and stir thoroughly until completely dissolved to obtain approximately 11.58 m³ of the solution. 3 A 200 g / L soda ash solution can be directly pumped into the leaching and impurity removal process. The prepared soda ash solution is slowly added dropwise to the solution in the leaching and impurity removal process, and after the addition is complete, the mixture is stirred thoroughly for 30 minutes to ensure a complete reaction. After filtration, the Fe and Al content is analyzed by ICP. The results show that the Fe content is 0.0001 g / L and the Al content is 0.3210 g / L, meeting the standard of Fe content ≤ 0.1 g / L and Al content ≤ 0.4 g / L.
[0081] Example 2 The lithium precipitation mother liquor from the lithium carbonate production line was collected and filtered through a filter press to obtain 20 ml of clarified mother liquor. 3 Titration analysis shows the current concentration of soda ash in the lithium precipitation mother liquor is 38 g / L. A target concentration of 150 g / L of soda ash needs to be prepared for saponification with extractant P507. 98% pure industrial soda ash will be used for replenishment. The amount M of soda ash to be added is calculated using the following process: The current amount of soda ash = 38 g / L × 20000 L = 760000 g; The target amount of soda ash = 150 g / L × 20000 L = 3000000 g; The target amount of soda ash added = (3,000,000 g - 760,000 g) / 98% ≈ 2286 kg.
[0082] 20 m 3 Add approximately 2286 kg of 98% industrial soda ash to the clarified mother liquor and stir vigorously until completely dissolved to obtain approximately 22.26 m³ of the solution. 3A 150 g / L soda ash solution was prepared. A certain volume of the P507-sulfonated kerosene organic phase (free acid concentration approximately 0.8 mol / L) was placed in a mixing chamber. The prepared soda ash solution was slowly added to the organic phase at a ratio (O / A) of 3:1. The mixture was stirred thoroughly for 10 minutes to allow the saponification reaction to proceed fully. After standing, the loaded organic phase and the saponified aqueous phase were separated. Samples were taken to analyze the pH value and degree of saponification of the loaded organic phase. The saponification rate of the organic phase was determined by acid-base titration. The results showed that the saponification rate of the organic phase was 45.2%, which stably reached and slightly exceeded the process target of 45%. This indicates that impurities in the lithium precipitation mother liquor (such as trace amounts of lithium and sulfate) have no significant negative impact on the saponification reaction of the P507 extractant.
[0083] Example 3 The lithium precipitation mother liquor from the lithium carbonate production line was collected and filtered through a filter press to obtain 15 ml of clarified mother liquor. 3 Titration analysis shows the current concentration of soda ash in the lithium precipitation mother liquor is 42 g / L. A target concentration of 300 g / L of soda ash needs to be prepared for saponification with extractant P204. Industrial soda ash with a purity of 98% is used for replenishment. The amount M of soda ash to be added is calculated using the following process: The current amount of soda ash = 42 g / L × 15000 L = 630000 g; The target quantity of soda ash = 300 g / L × 15000 L = 4500000 g; The target amount of soda ash added = (4,500,000 g - 630,000 g) / 98% ≈ 3,949 kg.
[0084] 15 m 3 Add approximately 3949 kg of 98% industrial soda ash to the clarified mother liquor and stir vigorously until completely dissolved to obtain approximately 18.95 m³. 3 A 150 g / L soda ash solution was prepared. The P204-kerosene organic phase (with a free acid concentration of approximately 1.0 mol / L) was placed in a mixing chamber. The prepared soda ash solution was slowly added to the organic phase at a ratio (O / A) of 4:1. The mixture was stirred thoroughly for 15 minutes to ensure sufficient contact between the high-concentration alkali solution and the organic phase, and to complete the saponification reaction. The mixture was allowed to stand and separate into the loaded organic phase and the saponified aqueous phase. Samples were taken to analyze the degree of saponification of the loaded organic phase. The results showed that the saponification rate of the organic phase was 45.5%, consistently meeting and slightly exceeding the process target of 45%.
[0085] Comparative Example 1 After pretreatment, the lithium precipitation mother liquor was clarified and collected at a depth of 11.58 m. 3The clarified mother liquor. Now, a target concentration of 200 g / L of soda ash needs to be prepared for pH adjustment in the leaching and impurity removal process. 98% pure industrial soda ash is used for replenishment, and the required amount of soda ash to be added is M = 11.58 × 1000 × 200 / 0.98 / 1000 ≈ 2363 kg. This solution is pumped into the leaching and impurity removal process. The prepared soda ash solution is slowly added dropwise to the solution in the leaching and impurity removal process. After the addition is complete, the mixture is stirred thoroughly for 30 minutes to ensure the reaction proceeds completely. After filtration, the Fe and Al content is analyzed by ICP. The results show that the Fe content is 0.0001 g / L and the Al content is 0.2610 g / L, meeting the standard of Fe content ≤ 0.1 g / L and Al content ≤ 0.4 g / L.
[0086] Comparative Example 2 After pretreatment, the lithium precipitation mother liquor was clarified and collected at a depth of 22.26 m. 3 The clarified mother liquor. Now, a target concentration of 150 g / L of soda ash is needed for the extraction and saponification process. 98% pure industrial soda ash is used for replenishment, and the required amount of soda ash is M = 22.26 × 1000 × 150 / 0.98 / 1000 ≈ 3373 kg. A certain volume of P507-sulfonated kerosene organic phase (free acid concentration approximately 0.8 mol / L) is placed in the mixing chamber. The prepared soda ash solution is slowly added to the organic phase at a ratio (O / A) of 3:1. The mixture is thoroughly mixed and stirred for 10 minutes to ensure complete saponification. The phases are separated by standing and separation, yielding the loaded organic phase and the saponified aqueous phase. Samples are taken to analyze the pH value and degree of saponification of the loaded organic phase. The saponification rate of the organic phase is determined by acid-base titration. The results show that the saponification rate of the organic phase is 45.8%, consistently reaching and slightly exceeding the process target of 45%.
[0087] Comparative Example 3 After pretreatment, the lithium precipitation mother liquor was clarified and collected at a depth of 18.95 m. 3 The clarified mother liquor. Now, a target concentration of 300 g / L soda ash is needed for the extraction and saponification process. 98% pure industrial soda ash is used for replenishment, and the required amount of soda ash is M = 18.95 × 1000 × 300 / 0.98 / 1000 ≈ 5801 kg. The P204-kerosene organic phase (free acid concentration approximately 1.0 mol / L) is placed in the mixing chamber. The prepared soda ash solution is slowly added to the organic phase at a ratio (O / A) of 4:1. The mixture is thoroughly stirred for 15 minutes to ensure sufficient contact between the high-concentration alkali solution and the organic phase and to complete the saponification reaction. The mixture is allowed to stand and separate the loaded organic phase and the saponified aqueous phase. Samples are taken to analyze the degree of saponification of the loaded organic phase. The saponification rate of the organic phase is determined using acid-base titration. The results show that the saponification rate of the organic phase is 46.0%, consistently reaching and slightly exceeding the process target of 45%.
[0088] The results of Example 1 and Comparative Example 1 show that, under the condition that the same target concentration of soda ash is required in the leaching and impurity removal process, Example 1 can save 2363 kg - 1582 kg = 781 kg of soda ash, with a saving rate of 33%. Meanwhile, 10 m 3 The highly alkaline mother liquor was fully utilized as a resource, avoiding the cost of neutralization treatment.
[0089] The results of Example 2 and Comparative Example 2 show that, under the condition that the same target concentration of soda ash is required in the extraction and saponification process, Example 2 can save 1087 kg of soda ash by 3373 kg - 2286 kg, achieving a saving rate of 32.2%. Simultaneously, 20 m³ of high-alkalinity lithium precipitation mother liquor can be utilized as a resource, avoiding neutralization disposal costs (approximately 3-4 tons of sulfuric acid can be saved based on neutralization to pH=7). Furthermore, it is demonstrated that impurities in the lithium precipitation mother liquor (such as trace amounts of lithium and sulfate) have no significant negative impact on the saponification reaction of the P507 extractant.
[0090] The results of Example 3 and Comparative Example 3 show that, under the condition that the extraction and saponification process requires the same target concentration of soda ash, Example 3 can save 1852 kg of soda ash: 5801 kg - 3949 kg = 1852 kg, with a saving rate of 31.9%. Meanwhile, 15 m 3 The high alkalinity lithium precipitation mother liquor can be utilized as a resource, avoiding the corresponding wastewater neutralization and disposal costs. Furthermore, it is shown that impurities in the lithium precipitation mother liquor have no adverse effect on the saponification reaction of the P204 extractant under higher alkalinity systems.
Claims
1. A method for recovering soda ash from lithium precipitation mother liquor, characterized in that, The method includes: A lithium precipitation mother liquor is provided, and the lithium precipitation mother liquor is subjected to solid-liquid separation to obtain a clarified mother liquor; Determine the current concentration of soda ash in the clarified mother liquor; Based on the target process for soda ash recycling, the target concentration of the soda ash is determined; Based on the current concentration of the soda ash and the target concentration of the soda ash, determine the target amount of soda ash to be added; The pre-added soda ash is added to the clarified mother liquor according to the target addition amount to form a soda ash solution with the target concentration, and then reused in the target process.
2. The method for recovering soda ash from lithium precipitation mother liquor as described in claim 1, characterized in that, The target process includes an extraction and saponification process and / or a leaching and impurity removal process.
3. The method for recovering soda ash from lithium precipitation mother liquor as described in claim 2, characterized in that, When the target process is the leaching and impurity removal process, after the soda ash with the target concentration is recycled to the target process, the pH of the solution in the leaching and impurity removal process is 4-5.
4. The method for recovering soda ash from lithium precipitation mother liquor as described in claim 2, characterized in that, The target concentration during the extraction and saponification process is calculated based on the reaction process between the pre-used extractant and the soda ash.
5. The method for recovering soda ash from lithium precipitation mother liquor as described in claim 1, characterized in that, The step of determining the target amount of soda ash to be added based on the current concentration and the target concentration of soda ash includes: Determine the purity of the pre-added soda ash; The target amount of soda ash is determined based on the target concentration and the solution volume of the target process. Calculate the current amount of soda ash based on the volume of the clarified mother liquor and the current concentration of soda ash in the clarified mother liquor; The target amount of soda ash to be added is determined based on the target amount of soda ash, the current amount of soda ash, and the purity of the soda ash to be added.
6. The method for recovering soda ash from lithium precipitation mother liquor as described in claim 1, characterized in that, The current concentration of soda ash in the clarified mother liquor is determined by titration.
7. The method for recovering soda ash from lithium precipitation mother liquor as described in claim 1, characterized in that, The solid-liquid separation methods include filtration and / or centrifugation.
8. A system for recovering soda ash from lithium precipitation mother liquor, employing the method for recovering soda ash from lithium precipitation mother liquor as described in any one of claims 1 to 7, characterized in that, The system includes: The pretreatment module is used to collect lithium precipitation mother liquor and perform solid-liquid separation to obtain clarified mother liquor; The component analysis module, connected to the pretreatment module, is used to analyze the current concentration of soda ash in the clarified mother liquor; The calculation module, connected to the component analysis module, is used to determine the target amount of soda ash to be added. A configuration module, connected to the pretreatment module and the calculation module, is used to add pre-added soda ash to the clarified mother liquor according to the target addition amount, and stir and mix to prepare a soda ash solution with the target concentration. The reuse conveying module is connected to the configuration module and is used to convey the configured soda ash solution with the target concentration to the target process.
9. The soda ash recovery system from lithium precipitation mother liquor as described in claim 8, characterized in that, The configuration module includes a mixing tank and a mechanical stirrer disposed within the mixing tank.
10. The soda ash recovery system from lithium precipitation mother liquor as described in claim 8, characterized in that, The component analysis module is also used to detect metal elements in the lithium precipitation mother liquor, so as to recover and utilize the metal elements in the lithium precipitation mother liquor.