A method for preparing battery lithium salt based on electrochemistry

Abstract

The present invention relates to the technical field of lithium compound preparation, specifically to a method for preparing lithium salt for batteries based on electrochemistry, comprising the following steps: preparing activated carbon, conductive additives and deionized water, and mixing and stirring the activated carbon, conductive additives and deionized water by a stirrer at room temperature to obtain four groups of uniformly mixed activated carbon flow electrode slurries; respectively circulating and pumping the four groups of activated carbon flow electrode slurries into the pole chambers at both ends of two groups of electrochemical devices, and simultaneously pumping lithium chloride solution and reactant solution into the desalination chambers of the two groups of electrochemical devices respectively, and the two groups of electrochemical devices are connected to electricity and perform electrochemical ion exchange reactions. The preparation method of the present invention is simple, the raw material price is cheap, the environmental impact is small, and the preparation energy consumption is low, which meets the requirements of green chemistry and sustainable development. The present invention achieves a high lithium ion recovery rate, improves resource utilization efficiency, reduces environmental pollution, and has significant economic and social benefits.

Description

Technical Field

[0001] The invention relates to the technical field of lithium compound preparation, and in particular to a method for preparing battery lithium salt based on electrochemistry. Background Art

[0002] In recent years, with the widespread application of lithium-ion batteries and the rise of the power vehicle industry, the demand for high-performance and high-safety lithium-ion batteries has been growing. The performance of lithium-ion batteries mainly depends on their positive and negative electrode materials. Among them, the positive electrode material has an important influence on the energy density, cycle life, safety and other aspects of the battery. At present, the commercial lithium-ion battery positive electrode materials mainly include lithium carbonate (Li 2 CO 3 ) and lithium hydroxide (LiOH), etc., mainly through low-cost metal salts to achieve the preparation of lithium-ion battery positive electrode materials.

[0003] However, when the existing technology is actually used, the traditional lithium salt preparation method will cause serious pollution to the environment, and the energy consumption generated during the preparation is high, which has caused certain difficulties for industrial production and development. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing battery lithium salt based on electrochemistry to solve the problems of serious pollution to the environment and high energy consumption.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for preparing a battery lithium salt based on electrochemistry, comprising the following steps:

[0006] S1. Material preparation: preparing activated carbon, conductive additives and deionized water, and mixing the activated carbon, conductive additives and deionized water with a stirrer at room temperature to obtain four groups of uniformly mixed activated carbon flow electrode slurries;

[0007] preparing a raw lithium salt solution and a reactant solution;

[0008] S2, ion separation: the four groups of activated carbon flow electrode slurries obtained in step S1 are respectively circulated and pumped into the electrode chambers at both ends of the two groups of electrochemical devices, and the raw lithium salt solution and the reactant solution are respectively pumped into the desalination chambers of the two groups of electrochemical devices, and the desalination chamber and the electrode chamber are separated by an ion membrane. The two groups of electrochemical devices are powered and perform electrochemical ion exchange reactions. The activated carbon flow electrode separates the ions of the raw lithium salt solution and the reactant solution under constant voltage or constant current, thereby obtaining A slurry and B slurry electrolyzed from the raw lithium salt solution, and C slurry and D slurry electrolyzed from the reactant solution. The electrochemical device includes a protective plate, an electrode chamber, a cation membrane, a desalination chamber and an anion membrane. Membrane, the number of the protective plate and the electrode chamber is two, wherein the protective plate, the electrode chamber, the cation membrane, the desalination chamber, the anion membrane, the electrode chamber and the protective plate are arranged one by one from front to back, and the two protective plates are fixedly connected by bolts, and sealing gaskets are respectively arranged between the protective plate and the electrode chamber, between the electrode chamber and the cation membrane, between the cation membrane and the desalination chamber, between the desalination chamber and the anion membrane, and between the anion membrane and the electrode chamber, a fluid groove is opened at one end of the electrode chamber corresponding to the position of the desalination chamber, and a brine chamber fluid support is arranged in the middle of the desalination chamber, and a water nozzle penetrating the electrode chamber and communicating with the inside of the fluid groove is fixed at one end of the protective plate, so that the activated carbon flow electrode circulates on the inner wall of the fluid groove;

[0009] S3, generating lithium salt: pumping the A slurry and the D slurry in step S2 into the electrode chambers at both ends of the new electrochemical device, and pumping deionized water into the desalination chamber of the electrochemical device, and reversely connecting the currents of the A slurry and the D slurry, so that the separated ions in the A slurry and the D slurry are combined in the deionized water under constant voltage or constant current to form a non-uniform lithium salt solution;

[0010] S4, obtaining a lithium salt product: stirring the deionized water containing cations and anions obtained in step S3 with a stirrer at room temperature for 6 to 8 hours to obtain a uniformly mixed lithium salt product solution.

[0011] Preferably, the mass ratio of activated carbon, conductive additive and deionized water in step S1 is (18-21): (0.5-1.5): (170-190), and the time for mixing and stirring by the stirrer in step S1 is greater than 24 hours.

[0012] Preferably, the stirrer in step S1 and step S4 is a magnetic stirrer, and the rotation speed of the magnetic stirrer is 700 r / min. In step S2, slurry A contains cations, and slurry D contains anions.

[0013] Preferably, the pump used in steps S2 and S3 is a peristaltic pump, the constant voltage or constant current voltage in steps S2 and S3 is 1.8 volts, and the power supply used in steps S2 and S3 is a DC power supply.

[0014] Preferably, in step S2, both end chambers of the electrochemical device into which the activated carbon flowing electrode slurry is pumped are inclined channel.

[0015] Preferably, the conductive additive in step S1 includes but is not limited to Ketjen black and acetylene black.

[0016] Preferably, the reactant solution in step S1 is a sodium hydroxide solution, and the ratio of lithium ion concentration to hydroxide ion concentration in the raw lithium salt solution and the sodium hydroxide solution is 1:1, and both are 500 mg / L, and the product lithium salt solution in step S4 is a lithium hydroxide solution.

[0017] Preferably, in step S1, the reactant solution is a sodium bicarbonate solution, and the ratio of lithium ion concentration to bicarbonate ion concentration in the raw lithium salt solution and the sodium bicarbonate solution is 1:1, and both are 1500 mg / L, and the product lithium salt solution in step S4 is a lithium bicarbonate solution, and step S4 further comprises:

[0018] S11, repeating steps S1-S4 to obtain a uniformly mixed and highly concentrated deionized water solution containing lithium bicarbonate, so that the lithium bicarbonate solutions obtained from multiple groups of raw lithium salt solutions and sodium bicarbonate solutions are enriched in the same mass fraction of deionized water;

[0019] S12, heating the deionized water solution containing lithium bicarbonate obtained in step S11 to 85° C. to precipitate lithium carbonate, and drying the lithium carbonate precipitate at 60° C. to obtain lithium carbonate powder.

[0020] Compared with the prior art, the beneficial effects of the present invention are: 1. The preparation method of the present invention is simple, the raw materials are cheap, the impact on the environment is small, and the energy consumption for preparation is low, which meets the requirements of green chemistry and sustainable development. The present invention achieves a high lithium ion recovery rate, improves resource utilization efficiency, reduces environmental pollution, and has significant economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a flow chart of step S2 and step S3 of embodiment 1 of the present invention;

[0022] Figure 2 This is a conductivity change diagram of Example 1 of the present invention;

[0023] Figure 3 This is a graph showing a change in lithium ion recovery rate according to Example 1 of the present invention;

[0024] Figure 4 This is a conductivity change diagram of lithium bicarbonate solution enriched in deionized water of the same mass fraction in Example 1 of the present invention;

[0025] Figure 5 is the XRD diagram of lithium carbonate in Example 1 of the present invention;

[0026] Figure 6 This is a flow chart of step S2 and step S3 of embodiment 2 of the present invention;

[0027] Figure 7 This is a conductivity change diagram of Example 2 of the present invention;

[0028] Figure 8 is an overall schematic diagram of the electrochemical device of the present invention;

[0029] Fig. 9 For the present invention Figure 8 A magnified view of the structure at center;

[0030] Fig.10 It is a schematic diagram of the structure of the electrode chamber of the electrochemical device of the present invention;

[0031] Fig.11 This is a schematic diagram of the structure of the desalination chamber of the electrochemical device of the present invention.

[0032] In the figure: 1. protective plate; 2. sealing gasket; 3. pole chamber; 4. cation membrane; 5. desalination chamber; 6. anion membrane; 7. water nozzle; 8. fluid trough; 9. brine chamber fluid support. DETAILED DESCRIPTION

[0033] 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.

[0034] Embodiment 1

[0035] See also Figure 1-5 8-11, the present invention provides a technical solution: a method for preparing a battery lithium salt based on electrochemistry, comprising the following steps:

[0036] S1. Material preparation: Prepare activated carbon, Ketjen black and deionized water in a mass ratio of 19:1:180, and mix and stir the activated carbon, conductive additive and deionized water with a magnetic stirrer at room temperature to obtain four groups of uniformly mixed activated carbon flow electrode slurries. The mixing and stirring time is greater than 24 hours, and the speed of the magnetic stirrer is 700 r / min.

[0037] Prepare impure low-valent lithium chloride solution and sodium bicarbonate solution, wherein the ratio of lithium ion concentration to bicarbonate ion concentration in the lithium chloride solution and the sodium bicarbonate solution is 1:1, and both are 1500 mg / L; S2, ion separation: the four groups of activated carbon flow electrode slurries obtained in step S1 are respectively circulated and pumped into the electrode chambers at both ends of the two groups of electrochemical devices, wherein the electrode chambers at both ends of the electrochemical device are inclined trough flow channels, and the lithium chloride solution and the sodium bicarbonate solution are respectively pumped into the desalination chambers of the two groups of electrochemical devices, and the desalination chambers and the electrode chambers are separated by ion membranes. The two groups of electrochemical devices are connected to a DC power supply and perform an electrochemical ion exchange reaction. By applying a forward voltage, lithium ions are reacted with chloride ions and sodium ions. The activated carbon flowing electrodes are separated from the bicarbonate ions in two sets of electrochemical devices, and the activated carbon flowing electrodes are used to perform ion separation on the lithium chloride solution and the sodium bicarbonate solution at a constant voltage or a constant current of 1.8 volts, and obtain A slurry containing lithium ions and B slurry containing chloride ions separated from the lithium chloride solution, and C slurry containing sodium ions and D slurry containing bicarbonate ions separated from the sodium bicarbonate solution. The electrochemical device includes a protective plate 1, an electrode chamber 3, a cation membrane 4, a desalination chamber 5 and an anion membrane 6. The number of the protective plate 1 and the electrode chamber 3 is two, wherein the protective plate 1, the electrode chamber 3, the cation membrane 4, the desalination chamber 5, the anion membrane 6, the electrode chamber 3 and The protective plates 1 are arranged one by one from front to back, and the two protective plates 1 are fixed and installed by bolts. Sealing gaskets 2 are respectively arranged between the protective plate 1 and the pole chamber 3, between the pole chamber 3 and the cation membrane 4, between the cation membrane 4 and the desalination chamber 5, between the desalination chamber 5 and the anion membrane 6, and between the anion membrane 6 and the pole chamber 3. A fluid groove 8 is opened at one end of the pole chamber 3 corresponding to the position of the desalination chamber 5, and a brine chamber fluid support 9 is arranged in the middle of the desalination chamber 5. A water nozzle 7 that penetrates the pole chamber 3 and is connected to the inside of the fluid groove 8 is fixed at one end of the protective plate 1, so that the activated carbon flow electrode circulates on the inner wall of the fluid groove 8, wherein the protective plate 1 is made of a metal plate, and the outer wall is wrapped with a rubber insulating layer to avoid passing through the bolts. Deformation occurs during installation. The sealing gasket 2 is made of polyvinyl chloride to ensure the sealing between the pole chamber and the cation membrane, the cation membrane and the desalination chamber, the desalination chamber and the anion membrane, and the anion membrane and the pole chamber to avoid water leakage. The pole chamber 3 is made of special materials. The fluid groove 8 arranged inside allows the activated carbon flow electrode to better contact the inside of the pole chamber 3, so that it is convenient to connect electricity through the pole chamber 3 to allow the activated carbon flow electrode to carry current. The cation membrane 4 and the anion membrane 6 are common ion exchange membranes on the market. The desalination chamber 5 is made of resin, and the brine chamber fluid support 9 is made of gauze, so that the speed of the internal liquid flowing inside the desalination chamber 5 is reduced, and the inside of the desalination chamber is more filled, so as to facilitate the ion separation or ion migration of the liquid;

[0038] S3, generating lithium salt: pumping the A slurry and the D slurry in step S2 into the electrode chambers at both ends of the new electrochemical device, and pumping deionized water into the desalination chamber of the electrochemical device, and reversely connecting the A slurry and the D slurry current to the DC power supply, and applying a reverse voltage to make the lithium ions and the bicarbonate ions desorbed into the deionized water by themselves, so as to achieve the effect of mixing into lithium bicarbonate. Since the salt ions will not occupy the separation sites of the material, it is equivalent to achieving in-situ regeneration of the electrode, and the conductive additive will increase the conductivity of the activated carbon flow electrode, promote the electrical separation of the active material, truly achieve a pseudo-infinite separation amount, and give full play to the separation effect of the active material, so that the ions separated in the A slurry and the D slurry are combined in the deionized water to form lithium salts under a constant voltage or constant current of 1.8 volts, and a lithium bicarbonate solution is generated;

[0039] The pump used in steps S2 and S3 is a peristaltic pump.

[0040] S4, obtaining a lithium salt product: stirring the deionized water containing cations and anions obtained in step S3 with a magnetic stirrer at room temperature for 6 to 8 hours at a speed of 700 r / min to obtain a uniformly mixed lithium salt solution.

[0041] Repeat steps S1-S4 to obtain a uniformly mixed and highly concentrated deionized water solution containing lithium bicarbonate, so that the lithium bicarbonate solutions obtained from multiple groups of lithium chloride solutions and sodium bicarbonate solutions are enriched in the same mass fraction of deionized water, thereby facilitating the dehydrogenation of the lithium bicarbonate solution, and then heat the deionized water solution containing lithium bicarbonate to 85° C. to precipitate lithium carbonate, and dry the lithium carbonate precipitate at 60° C. to obtain lithium carbonate powder, thereby completing the preparation of the product lithium salt.

[0042] First, the preparation method simplifies the preparation process, reduces the difficulty of preparation, and improves production efficiency. The raw materials used in this embodiment are impure lithium chloride solution and sodium bicarbonate solution, which are cheap, so that the impure lithium chloride that should be processed can be utilized. Compared with the existing actual production technology of lithium carbonate, the preparation method is simple, and it can be prepared without the use of acid, which reduces production costs and reduces waste of resources. Furthermore, the preparation method has a small impact on the environment, meets the requirements of green chemistry and sustainable development, and the present invention achieves a high lithium ion recovery rate, improves resource utilization efficiency, and reduces environmental pollution. In summary, the present invention not only has the advantages of simple preparation method, cheap raw material price, and small environmental impact, but also achieves a high lithium ion recovery rate, with significant economic and social benefits, wherein in this embodiment, impure lithium chloride is used as a representative to reuse impure lithium salt solution to synthesize lithium carbonate.

[0043] Embodiment 2

[0044] See also Figure 6-7 , including the following steps:

[0045] S1. Material preparation: 10 g of activated carbon, 0.5 g of Ketjen black and 90 g of deionized water were prepared, and the activated carbon, conductive additive and deionized water were mixed and stirred by a magnetic stirrer at room temperature to obtain four groups of uniformly mixed activated carbon flow electrode slurries. The mixing and stirring time was greater than 24 h, and the speed of the magnetic stirrer was 700 r / min.

[0046] Prepare a lithium sulfate solution and a sodium hydroxide solution, wherein the ratio of lithium ion concentration to hydroxide ion concentration in the lithium sulfate solution and the sodium hydroxide solution is 1:1, and both are 500 mg / L;

[0047] S2, ion separation: the four groups of activated carbon flow electrode slurries obtained in step S1 are respectively pumped into the electrode chambers at both ends of the two groups of electrochemical devices at a uniform speed of 30 mL / min, wherein the electrode chambers at both ends of the electrochemical devices are inclined channel, and the lithium sulfate solution and the sodium hydroxide solution are respectively pumped into the desalination chambers of the two groups of electrochemical devices, and the desalination chambers and the electrode chambers are separated by ion membranes. The two groups of electrochemical devices are connected to a DC power supply and perform electrochemical ion exchange reactions. The activated carbon flow electrode performs ion separation on the lithium sulfate solution and the sodium hydroxide solution at a constant voltage or constant current of 1.8 volts, and obtains A slurry containing lithium ions and B slurry containing sulfate ions separated from the lithium sulfate solution, and C slurry containing sodium ions and D slurry containing hydroxide ions separated from the sodium hydroxide solution;

[0048] S3, generating lithium salt: pumping the A slurry and the D slurry in step S2 into the electrode chambers at both ends of the new electrochemical device, and pumping deionized water into the desalination chamber of the electrochemical device, and reversely connecting the A slurry and the D slurry current to the DC power supply, and applying a reverse voltage to make the lithium ions and the hydroxide ions desorbed into the deionized water by themselves, so as to achieve the effect of mixing into lithium hydroxide. Since the salt ions will not occupy the separation sites of the material, it is equivalent to achieving the in-situ regeneration of the electrode, and the conductive additive will increase the conductivity of the activated carbon flow electrode, promote the electrical separation of the active material, and truly achieve a pseudo-infinite separation amount, giving full play to the separation effect of the active material, so that the ions separated in the A slurry and the D slurry are combined in the deionized water to form lithium salts under a constant voltage or constant current of 1.8 volts, and a lithium hydroxide solution is generated;

[0049] The pump used in steps S2 and S3 is a peristaltic pump.

[0050] S4, obtaining the lithium salt product: stirring the deionized water containing cations and anions obtained in step S3 with a magnetic stirrer at room temperature for 6 to 8 hours at a speed of 700 r / min to obtain a uniformly mixed lithium hydroxide solution.

[0051] The lithium hydroxide solution prepared by the present invention has a simple preparation method, cheap raw materials, less environmental impact and low preparation energy consumption. Through the innovative electrochemical method, not only the preparation process is simplified and the raw material cost is reduced, but also the impact of the preparation process on the environment is significantly reduced. At the same time, the method has low energy consumption and improves the preparation efficiency, providing a new efficient, environmentally friendly and economical way for the industrial production of lithium hydroxide.

[0052] Embodiment 3

[0053] The difference from the second embodiment is that:

[0054] A method for preparing calcium sulfate is also provided:

[0055] The following steps are involved:

[0056] S1. Material preparation: 10 g of activated carbon, 0.5 g of Ketjen black and 90 g of deionized water were prepared, and the activated carbon, conductive additive and deionized water were mixed and stirred by a magnetic stirrer at room temperature to obtain four groups of uniformly mixed activated carbon flow electrode slurries. The mixing and stirring time was greater than 24 h, and the speed of the magnetic stirrer was 700 r / min.

[0057] Prepare a calcium chloride solution and a sodium sulfate solution, wherein the ratio of calcium ion concentration to sulfate ion concentration in the calcium chloride solution and the sodium sulfate solution is 1:1, and both are 500 mg / L;

[0058] S2, ion separation: the four groups of activated carbon flow electrode slurries obtained in step S1 are respectively pumped into the electrode chambers at both ends of the two groups of electrochemical devices at a uniform speed of 30 mL / min, wherein the electrode chambers at both ends of the electrochemical devices are inclined channel, and the calcium chloride solution and the sodium sulfate solution are respectively pumped into the desalination chambers of the two groups of electrochemical devices, and the desalination chambers and the electrode chambers are separated by ion membranes. The two groups of electrochemical devices are connected to a DC power supply and perform electrochemical ion exchange reactions. The activated carbon flow electrode performs ion separation on the calcium chloride solution and the sodium sulfate solution at a constant voltage or constant current of 1.2 volts, and obtains A slurry containing calcium ions and B slurry containing chloride ions separated from the calcium chloride solution, and C slurry containing sodium ions and D slurry containing sulfate ions separated from the sodium sulfate solution;

[0059] S3, generating calcium salt: pumping the A slurry and the D slurry in step S2 into the electrode chambers at both ends of the new electrochemical device, and pumping deionized water into the desalination chamber of the electrochemical device, and reversely connecting the A slurry and the D slurry current to the DC power supply, and applying a reverse voltage so that the calcium ions and the sulfate ions are self-desorbed into the deionized water, thereby achieving the effect of mixing into calcium sulfate. Since the salt ions will not occupy the separation sites of the material, it is equivalent to achieving in-situ regeneration of the electrode, and the conductive additive will increase the conductivity of the activated carbon flow electrode, promote the electrical separation of the active material, truly achieve a pseudo-infinite separation amount, and give full play to the separation effect of the active material, so that the ions separated in the A slurry and the D slurry are combined in the deionized water under a constant voltage or constant current of 1.8 volts to form calcium salts, and generate a calcium sulfate solution;

[0060] The pump used in steps S2 and S3 is a peristaltic pump.

[0061] S4, obtaining the calcium salt product: the deionized water containing cations and anions obtained in step S3 is stirred by a magnetic stirrer at room temperature for 6 to 8 hours at a speed of 700 r / min to obtain a uniformly mixed calcium sulfate solution.

[0062] Embodiment 4

[0063] A method for preparing lithium chloride is also provided:

[0064] S1. Material preparation: 10 g of activated carbon, 0.5 g of Ketjen black and 90 g of deionized water were prepared, and the activated carbon, conductive additive and deionized water were mixed and stirred by a magnetic stirrer at room temperature to obtain four groups of uniformly mixed activated carbon flow electrode slurries. The mixing and stirring time was greater than 24 h, and the speed of the magnetic stirrer was 700 r / min.

[0065] Prepare a sodium chloride solution and a lithium sulfate solution, wherein the ratio of chloride ion concentration to lithium ion concentration in the sodium chloride solution and the lithium sulfate solution is 1:1, and both are 500 mg / L;

[0066] S2, ion separation: the four groups of activated carbon flow electrode slurries obtained in step S1 are respectively pumped into the electrode chambers at both ends of the two groups of electrochemical devices at a uniform speed of 30 mL / min, wherein the electrode chambers at both ends of the electrochemical devices are inclined channel, and the sodium chloride solution and the lithium sulfate solution are respectively pumped into the desalination chambers of the two groups of electrochemical devices, and the desalination chambers and the electrode chambers are separated by ion membranes. The two groups of electrochemical devices are connected to a DC power supply and perform electrochemical ion exchange reaction. The activated carbon flow electrode performs ion separation on the sodium chloride solution and the lithium sulfate solution at a constant voltage or constant current of 1.2 volts, and obtains A slurry containing chloride ions and B slurry containing sodium ions separated from the sodium chloride solution, and C slurry containing sodium sulfate ions and D slurry containing lithium ions separated from the lithium sulfate solution;

[0067] S3, generating lithium salt: pumping the A slurry and the D slurry in step S2 into the electrode chambers at both ends of the new electrochemical device, and pumping deionized water into the desalination chamber of the electrochemical device, and reversely connecting the A slurry and the D slurry current to the DC power supply, and applying a reverse voltage to make the chloride ions and lithium ions desorbed into the deionized water by themselves, so as to achieve the effect of mixing into lithium chloride. Since the salt ions will not occupy the separation sites of the material, it is equivalent to achieving in-situ regeneration of the electrode, and the conductive additive will increase the conductivity of the activated carbon flow electrode, promote the electrical separation of the active material, and truly achieve a pseudo-infinite separation amount, giving full play to the separation effect of the active material, so that the ions separated in the A slurry and the D slurry under a constant voltage or constant current of 1.8 volts are combined in the deionized water to form ionic compounds, and a lithium chloride solution is generated;

[0068] The pump used in steps S2 and S3 is a peristaltic pump.

[0069] S4, obtaining the lithium salt product: stirring the deionized water containing chloride ions and lithium ions obtained in step S3 with a magnetic stirrer at room temperature for 6 to 8 hours at a speed of 700 r / min to obtain a uniformly mixed lithium chloride solution.

[0070] First, the preparation method simplifies the preparation process, reduces the difficulty of preparation, and improves production efficiency. The raw materials used in this embodiment are sodium chloride solution and lithium sulfate solution, which are cheap, reduce production costs, and reduce waste of resources. Furthermore, the preparation method has a small impact on the environment, meets the requirements of green chemistry and sustainable development, improves resource utilization efficiency, and reduces environmental pollution. In summary, the present invention not only has the advantages of simple preparation method, cheap raw material price, and small environmental impact, but also has significant economic and social benefits.

[0071] In the above embodiment, it can be known from the calculation of drug prices in Aladdin:

[0072] Example 2: Lithium sulfate about 2.9 yuan per gram and sodium hydroxide about 0.1 yuan per gram synthesize lithium hydroxide about 5.3 yuan per gram;

[0073] Example 3: Calcium chloride is about 82.4 yuan per gram and sodium sulfate is about 1 yuan per gram to synthesize calcium sulfate, which is about 185.4 yuan per gram;

[0074] Example 4: Sodium chloride is about 0.3 yuan per gram and lithium sulfate is about 2.9 yuan per gram to synthesize lithium chloride at about 144.1 yuan per gram;

[0075] The above drug price calculation only reflects the price of the drug sold by Aladdin at the time the patent was written.

[0076] Therefore, the technical solution provided by the present invention can generate high-value reactants from low-value reactants, and compared with the prior art, it does not require reagents such as acids and alkalis, has lower energy consumption, and reduces the impact of the preparation process on the environment.

[0077] 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.

[0078] 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 preparing a battery lithium salt based on electrochemistry, characterized in that: The following steps are involved: S1. Material preparation: preparing activated carbon, conductive additives and deionized water, and mixing the activated carbon, conductive additives and deionized water with a stirrer at room temperature to obtain four groups of uniformly mixed activated carbon flow electrode slurries; preparing a raw material lithium salt solution and a reactant solution; S2, ion separation: the four groups of activated carbon flow electrode slurries obtained in step S1 are respectively circulated and pumped into the electrode chambers at both ends of the two groups of electrochemical devices, and the raw lithium salt solution and the reactant solution are respectively pumped into the desalination chambers of the two groups of electrochemical devices, and the desalination chambers and the electrode chambers are separated by ion membranes. The two groups of electrochemical devices are powered and perform electrochemical ion exchange reactions. The activated carbon flow electrodes separate the ions of the raw lithium salt solution and the reactant solution under constant voltage or constant current, thereby obtaining A slurry and B slurry electrolyzed from the raw lithium salt solution, and C slurry and D slurry electrolyzed from the reactant solution. The electrochemical device comprises a protective plate (1), an electrode chamber (3), a cationic membrane (4), a desalination chamber (5) and an anionic membrane (6), wherein the number of the protective plate (1) and the electrode chamber (3) is two, wherein the number of the protective plate (1), the electrode chamber (3), the cationic membrane (4), the desalination chamber (5) and the anionic membrane (6) is two. The ion membrane (4), the desalination chamber (5), the anion membrane (6), the electrode chamber (3) and the protection plate (1) are arranged one after another from front to back, and the two protection plates (1) are fixedly connected by bolts. Sealing gaskets (2) are respectively provided between the protection plate (1) and the electrode chamber (3), between the electrode chamber (3) and the cation membrane (4), between the cation membrane (4) and the desalination chamber (5), between the desalination chamber (5) and the anion membrane (6), and between the anion membrane (6) and the electrode chamber (3). A fluid groove (8) is provided at one end of the electrode chamber (3) corresponding to the position of the desalination chamber (5), and a salt water chamber fluid support (9) is provided in the middle of the desalination chamber (5). A water nozzle (7) penetrating the electrode chamber (3) and communicating with the inside of the fluid groove (8) is fixedly provided at one end of the protection plate (1), so that the activated carbon flow electrode circulates on the inner wall of the fluid groove (8); S3, generating lithium salt: pumping the A slurry and the D slurry in step S2 into the electrode chambers at both ends of the new electrochemical device, and pumping deionized water into the desalination chamber of the electrochemical device, and reversely connecting the currents of the A slurry and the D slurry, so that the separated ions in the A slurry and the D slurry are combined in the deionized water under constant voltage or constant current to form a non-uniform lithium salt solution; S4, obtaining a lithium salt product: stirring the deionized water containing cations and anions obtained in step S3 with a stirrer at room temperature for 6 to 8 hours to obtain a uniformly mixed lithium salt product solution.

2. The method for preparing a battery lithium salt based on electrochemistry according to claim 1, characterized in that: The mass ratio of activated carbon, conductive additive and deionized water in step S1 is (18-21): (0.5-1.5): (170-190), and the mixing and stirring time by the stirrer in step S1 is greater than 24 hours.

3. The method for preparing a battery lithium salt based on electrochemistry according to claim 1, characterized in that: The stirrer in step S1 and step S4 is a magnetic stirrer, and the rotation speed of the magnetic stirrer is 700 r / min. In step S2, slurry A contains cations, and slurry D contains anions.

4. The method for preparing a battery lithium salt based on electrochemistry according to claim 1, characterized in that: The pump used in the steps S2 and S3 is a peristaltic pump, the constant voltage or constant current voltage in the steps S2 and S3 is 1.8 volts, and the power supply used in the steps S2 and S3 is a DC power supply.

5. The method for preparing a battery lithium salt based on electrochemistry according to claim 1, characterized in that: In the step S2, both end chambers of the electrochemical device into which the activated carbon flowing electrode slurry is pumped are inclined channel.

6. The method for preparing a battery lithium salt based on electrochemistry according to claim 1, characterized in that: The conductive additive in step S1 includes but is not limited to Ketjen black and acetylene black.

7. The method for preparing a battery lithium salt based on electrochemistry according to claim 1, characterized in that: In the step S1, the reactant solution is a sodium hydroxide solution, and the ratio of lithium ion concentration to hydroxide ion concentration in the raw lithium salt solution and the sodium hydroxide solution is 1:1, and both are 500 mg / L. In the step S4, the product lithium salt solution is a lithium hydroxide solution.

8. The method for preparing a battery lithium salt based on electrochemistry according to claim 1, characterized in that: In the step S1, the reactant solution is a sodium bicarbonate solution, and the ratio of lithium ion concentration to bicarbonate ion concentration in the raw lithium salt solution and the sodium bicarbonate solution is 1:1, and both are 1500 mg / L. In the step S4, the product lithium salt solution is a lithium bicarbonate solution, and the step S4 further comprises: S11, repeating steps S1-S4 to obtain a uniformly mixed and highly concentrated deionized water solution containing lithium bicarbonate, so that the lithium bicarbonate solutions obtained from multiple groups of raw lithium salt solutions and sodium bicarbonate solutions are enriched in the same mass fraction of deionized water; S12, heating the deionized water solution containing lithium bicarbonate obtained in step S11 to 85° C. to precipitate lithium carbonate, and drying the lithium carbonate precipitate at 60° C. to obtain lithium carbonate powder.

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