Lithium extraction from brine

Abstract

The application relates to a brine lithium extraction device and method, which comprises an electrolytic box (1), a titanium electrode (2), an electroactive membrane electrode (3), a power supply (4), a gas collecting device (5) and a flushing device (6). An electrolytic cell is formed in the electrolytic box. An air outlet (12) and a flushing port (13) are arranged at the top of the electrolytic box. A feeding port (14) is arranged on the side wall. A drainage port (15) is arranged at the bottom of the side wall. A flocculation discharge port (16) and a concentrated liquid discharge port (17) are arranged at the bottom. The gas collecting device (5) is communicated with the air outlet. The titanium electrode is arranged in the electrolytic cell. The electroactive membrane electrode is arranged in the electrolytic cell. The electroactive membrane electrode is provided with a lithium ion sieve. The power supply is electrically connected with the electroactive membrane electrode and the titanium electrode. The flushing device is communicated with the flushing port. In the application, the brine can be quickly extracted for lithium and boron removal.

Description

Technical Field

[0001] This invention relates to an apparatus and a method for extracting lithium ions from brine. Background Technology

[0002] Lithium is an important strategic resource, and lithium and its compounds have wide applications in batteries, rubber, aerospace, and other fields. Lithium hydroxide is an important raw material in the field of power batteries. Boron has a wide range of uses; boric acid is one of the basic raw materials for producing other borides, and the boron compounds produced from it are widely used in defense and other fields.

[0003] Salt lake brines contain abundant resources such as potassium, lithium, boron, and magnesium. However, the lithium, magnesium, and boron resources in the old brine after potassium extraction are not fully utilized. The efficient extraction and recovery of high-value-added ions such as lithium and boron from brine (old brine) and their conversion into corresponding products have good application prospects.

[0004] Currently, the main separation technologies for target ions in salt lake brine include ion exchange, adsorption and membrane separation, and solvent extraction. Among these, adsorption and ion exchange are low-cost and simple to operate, but the adsorption and ion exchange processes mainly rely on the physical and chemical diffusion of ions, which is slow and time-consuming. Membrane separation methods offer high selectivity, good separation effect, require no additives, are simple in process, and are easy to automate, but the cost of membranes is relatively high. Most research on solvent extraction for the recovery of lithium and boron resources from salt lake brine is conducted in steps, i.e., firstly, multi-stage series extraction and back-extraction are performed to separate boron, and then multi-stage extraction is performed to separate lithium / magnesium. The entire separation process suffers from problems such as cumbersome procedures, high energy and material consumption, severe equipment corrosion, and extractant loss.

[0005] The purpose of this invention is to solve the problems of cumbersome process, high energy consumption, and extractant loss in existing methods for extracting lithium and boron ions from brine or old brine. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a lithium extraction device from brine, comprising an electrolytic tank 1, a titanium electrode 2, an electroactive membrane electrode 3, a power supply 4, a gas collecting device 5, and a rinsing device 6. The electrolytic tank 1 contains an electrolytic cell 11. The top of the electrolytic tank 1 has a gas outlet 12 and a rinsing port 13. The upper part of the side wall has a feed inlet 14, the bottom of the side wall has a drain outlet 15, and the bottom of the electrolytic tank 1 has a flocculant discharge outlet 16 and a concentrate discharge outlet 17. The gas collecting device 5 is connected to the gas outlet 12. The titanium electrode 2 and the electroactive membrane electrode 3 are disposed within the electrolytic cell 11, and a lithium-ion sieve 31 is mounted on the electroactive membrane electrode 3. The power supply 4 is electrically connected to both the electroactive membrane electrode 3 and the titanium electrode 2. The rinsing device 6 is connected to the rinsing port 13.

[0007] In use, brine is introduced into electrolytic cell 11, and power supply 4 is turned on to carry out an electrolytic reaction, generating boric acid flocculents and oxygen. Lithium ions in the brine are embedded in lithium ion sieve 31. Oxygen is discharged into gas collecting device 5, and boric ions are collected after the boric acid flocculents are discharged. Then, after rinsing electrolytic cell 11 with a cleaning device, lithium hydroxide solution is introduced into electrolytic cell 11, and power supply 4 is turned on to carry out an electrolytic reaction, generating hydrogen gas. Lithium ions on lithium ion sieve 31 undergo deintercalation to generate lithium hydroxide. The lithium hydroxide solution is concentrated, and hydrogen gas is discharged into gas collecting device 5. When the lithium hydroxide solution in electrolytic cell 11 reaches a certain concentration, the lithium hydroxide solution is discharged from concentrated liquid discharge port 17 into concentrated liquid storage tank 8 to recover lithium ions.

[0008] This invention, by setting a titanium electrode 2 and an electroactive membrane electrode 3 in an electrolytic cell 11 and electrically connecting a power supply 4 to the electroactive membrane electrode 3 and the titanium electrode 2, forms a circuit to carry out an electrolytic reaction, generating boric acid and extracting boron ions. A lithium ion sieve 31 is set on the electroactive membrane electrode 3, which can adsorb ions in the brine during the electrolytic reaction and release the adsorbed ions, thereby extracting lithium ions. This invention has a simple structure, is easy to use, and does not require an extractant. It can solve the problems of cumbersome process, high energy consumption, and extractant loss in the existing technology for extracting lithium and boron ions from brine.

[0009] Preferably, it also includes a settling tank 7 and a concentrate storage tank 8, with the settling tank 7 connected to the discharge outlet and the concentrate storage tank 8 connected to the concentrate discharge outlet 17.

[0010] Preferably, the titanium electrode 2 is one of a titanium mesh electrode, a titanium sheet electrode, and a titanium plate electrode.

[0011] Preferably, the lithium ion sieve 31 is one of manganese-based lithium ion sieve 31, vanadium-based lithium ion sieve 31, and iron-based lithium ion sieve 31.

[0012] Preferably, the gas collecting device 5 includes an oxygen storage tank 51 and a hydrogen storage tank 52, and the gas outlet 12 includes an oxygen outlet 121 and a hydrogen outlet 122. The inlet of the oxygen storage tank 51 is connected to the oxygen outlet 121, and the inlet of the hydrogen storage tank 52 is connected to the hydrogen outlet 122. An oxygen exhaust valve 123 is provided on the oxygen outlet 121, and a hydrogen exhaust valve 124 is provided on the hydrogen outlet 122. The oxygen produced by the reaction can be stored in the oxygen storage tank 51, and the hydrogen produced by the reaction can be stored in the hydrogen storage tank 52.

[0013] Preferably, a first blower 53 and an oxygen exhaust valve 123 are provided at the oxygen outlet 12, and a second blower 54 is provided at the hydrogen outlet 12. By providing the first blower 53 at the oxygen outlet 12, the oxygen generated in the electrolytic cell 11 can be vented, and by providing the second blower 54 and the hydrogen exhaust valve 124 at the hydrogen outlet 12, the hydrogen generated in the electrolytic cell 11 can be vented, preventing the mixing of hydrogen and oxygen.

[0014] Preferably, the rinsing device 6 includes a rinsing pipe 61 and a rinsing pump 62, with one end of the rinsing pipe 61 connected to the rinsing port 13 and the other end connected to the rinsing pump 62.

[0015] Preferably, a filter screen 18 is provided at the drain outlet 15. The filter screen 18 at the drain outlet 15 prevents boric acid flocculants generated in the electrolytic cell 11 from being discharged from the drain outlet 15. A drain valve 151 is provided on the drain outlet 15. A flocculant discharge valve 161 is provided on the flocculant discharge outlet 16, and a concentrate discharge valve 171 is provided on the concentrate discharge outlet 17.

[0016] The method for extracting lithium from brine, using any of the above-mentioned brine lithium extraction devices, includes: a lithium and boron separation step S1, in which brine is added to an electrolytic cell 11, the positive electrode of a power supply 4 is electrically connected to a titanium electrode 2, and the negative electrode is electrically connected to an electroactive membrane electrode 3, and the power supply 4 is turned on to carry out an electrolytic reaction, generating boric acid flocculants and oxygen, and lithium ions in the brine are embedded in a lithium ion sieve 31.

[0017] In discharge step S2, after lithium and boron separation is completed, the drain valve 151 is opened to discharge the solution in the electrolytic cell 11 through the drain outlet 15. In floc determination step S3, it is determined whether the boric acid flocs precipitated at the bottom of the electrolytic cell 11 have increased to a specified amount. If so, the process returns to step S1; otherwise, it proceeds to step S4, which involves discharging the boric acid flocs.

[0018] In the boric acid flocculant discharge step S4, power supply 4 is turned off, and flocculant discharge valve 161 is opened to discharge the flocculated product into the settling tank 7. In the cleaning step S5, flushing pump 62 is turned on to flush the electrolytic cell 11, titanium electrode 2, and electroactive membrane electrode 3; the flushing water is discharged from the drain outlet. In the regeneration step S6, lithium hydroxide solution is added to the electrolytic cell 11. The negative terminal of power supply 4 is electrically connected to titanium electrode 2, and the positive terminal is electrically connected to electroactive membrane electrode 3. Power supply 4 is turned on, causing lithium ions on the lithium ion sieve 31 to deintercalate and enter the lithium hydroxide solution.

[0019] Preferably, in the lithium-boron separation step S1, the power supply voltage is 1~8 V, and in the regeneration step S6, the power supply voltage is 1~10 V.

[0020] In this invention, lithium ions can be selectively extracted and regenerated via the electroactive membrane electrode 3, while borate ions can be removed by combining with H+ to form flocculation products. The synergistic effect of these two processes significantly improves the efficiency of lithium extraction and boron removal. This invention features a simple process that requires no additional chemical reagents, avoids secondary pollution, and generates high-value-added products such as oxygen, hydrogen, and flocculation products like boric acid and lithium hydroxide. It solves the problems of cumbersome processes, high energy consumption, extractant loss, and pollution associated with existing methods for extracting lithium and boron ions from brine. Attached Figure Description

[0021] Figure 1 Schematic diagram of a lithium extraction device from brine;

[0022] Figure 2 Schematic diagram of the internal structure of the electrolysis tank;

[0023] Figure 3 Schematic diagram of lithium ion extraction method;

[0024] Figure 4 Schematic diagram of lithium-ion intercalation reaction state;

[0025] Figure 5 Schematic diagram of lithium-ion intercalation / deintercalation reaction state.

[0026] In the diagram, 1. Electrolytic box, 11. Electrolytic cell, 12. Gas outlet, 121. Oxygen outlet, 122. Hydrogen outlet, 123. Oxygen exhaust valve, 124. Hydrogen exhaust valve, 13. Flushing port, 14. Feed inlet, 15. Drain outlet, 151. Drain valve, 16. Flocculant discharge outlet, 161. Flocculant discharge valve, 17. Concentrate discharge outlet, 171. Concentrate discharge valve, 18. Filter screen, 2. Titanium electrode, 3. Electroactive membrane electrode, 31. Lithium ion sieve, 4. Power supply, 5. Gas collection device, 51. Oxygen storage tank, 52. Hydrogen storage tank, 53. First blower, 54. Second blower, 6. Flushing device, 61. Flushing pipe, 62. Flushing pump, 7. Sedimentation tank, 8. Concentrate storage tank, 9. Control device, 91. Electrolysis module, 92. Flushing module, 93. Regeneration module. Detailed Implementation

[0027] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0028] like Figure 1 and Figure 2As shown, the brine lithium extraction device includes an electrolytic tank 1, a titanium electrode 2, an electroactive membrane electrode 3, a power supply 4, a gas collection device 5, a rinsing device 6, a settling tank 7, a concentrate storage tank 8, and a control device 9. An electrolytic cell 11 is formed inside the electrolytic tank 1. The top of the electrolytic tank 1 is provided with an oxygen outlet 121, a hydrogen outlet 122, and a rinsing port 13. The upper part of the side wall is provided with a feed inlet 14, the bottom of the side wall is provided with a drain outlet 15, and the bottom of the electrolytic tank 1 is provided with a flocculant discharge outlet 16 and a concentrate discharge outlet 17.

[0029] A drain valve 151 is installed on the drain outlet 15, a flocculant discharge valve 161 is installed on the flocculant discharge outlet 16, and a concentrate discharge valve 171 is installed on the concentrate discharge outlet 17.

[0030] A filter screen 18 is installed inside the electrolytic cell 11. The filter screen 18 is fixedly installed inside the electrolytic cell 11 and is fixedly connected to the inner side wall of the electrolytic tank 1, covering the drain outlet 15. The filter screen 18 installed at the drain outlet 15 can prevent the boric acid flocculent generated in the electrolytic cell 11 from being discharged from the drain outlet 15.

[0031] An oxygen exhaust valve 123 and a first blower 53 are installed at the oxygen outlet 121, and a hydrogen exhaust valve 124 and a second blower 54 are installed at the hydrogen outlet 122. The first blower 53 at the oxygen outlet 12 is used to vent the oxygen generated in the electrolytic cell 11, and the second blower 54 at the hydrogen outlet 12 is used to vent the hydrogen generated in the electrolytic cell 11, thus preventing the mixing of hydrogen and oxygen.

[0032] The gas collection device 5 includes an oxygen storage tank 51 and a hydrogen storage tank 52. The inlet of the oxygen storage tank 51 is connected to the oxygen outlet 121, and the inlet of the hydrogen storage tank 52 is connected to the hydrogen outlet 122. The oxygen storage tank 51 is used to store the oxygen produced in the reaction, and the hydrogen storage tank 52 is used to store the hydrogen produced in the reaction.

[0033] Multiple titanium electrodes 2 are arranged at certain intervals within the electrolytic cell 11. In this embodiment, the titanium electrodes 2 are titanium mesh electrodes, titanium sheet electrodes, and titanium plate electrodes. The material of the titanium electrodes 2 is ruthenium-iridium-titanium coated electrodes or ruthenium-iridium-tin-titanium coated electrodes. Compared with other materials, titanium electrodes 2 have a longer service life, which can improve the service life of the device and also improve corrosion resistance.

[0034] like Figure 3As shown, multiple electroactive membrane electrodes 3 are disposed within the electrolytic cell 11. Each electroactive membrane electrode 3 is located to the side of the titanium electrode 2, forming an electrode pair with the titanium electrode 2. A lithium-ion sieve 31 is coated on the electroactive membrane electrode 3. The lithium-ion sieve 31 is one of a manganese-based lithium-ion sieve, a vanadium-based lithium-ion sieve, or an iron-based lithium-ion sieve. Coating the surface of the electroactive membrane electrode 3 with a lithium-ion sieve 31 exposes more intrinsic active sites, increases the reaction rate, reduces the overpotential of the reaction, and helps reduce operating energy consumption.

[0035] When brine is introduced into electrolytic cell 11 for electrolysis, ions in the brine can be selectively adsorbed and released, thereby extracting lithium ions. Borate ions can also be removed by combining with H+ to form flocculation products. The two processes work synergistically, greatly improving the efficiency of lithium extraction and boron removal.

[0036] By utilizing multiple pairs of titanium electrodes 2 and electroactive membrane electrodes 3, the reaction rate can be greatly increased, the reaction time can be significantly reduced, and the operating potential can be effectively lowered.

[0037] The rinsing device 6 includes a rinsing pipe 61 and a rinsing pump 62. One end of the rinsing pipe 61 is connected to the rinsing port 13, and the other end is connected to the rinsing pump 62. By pumping in cleaning water, the electrolytic cell 11 and the titanium electrode 2 and electroactive membrane electrode 3 inside can be rinsed to prevent residual solution from affecting the next reaction.

[0038] Settling tank 7 is connected to the discharge outlet and is used to recover and store boric acid flocculants produced by the reaction.

[0039] The concentrated liquid storage tank 8 is connected to the concentrated liquid discharge port 17 and is used to recover and store concentrated lithium hydroxide solution.

[0040] The power supply 4, gas collection device 5, pump, etc. are controlled by the control device 9. The control device 9 includes an electrolysis module 91, a flushing module 92, and a regeneration module 93. The electrolysis module 91 is electrically connected to the power supply 4, the first blower 53, the oxygen exhaust valve 123, the drain valve 151, and the flocculant discharge valve 161. The flushing module 92 is electrically connected to the flushing device 6 and the drain valve 151. The regeneration module 93 is electrically connected to the power supply 4, the second blower 54, the hydrogen exhaust valve 124, and the concentrate discharge valve 171.

[0041] When using the brine lithium extraction device, firstly, the brine is introduced into the electrolytic cell 11 through the feed inlet 14, and the power supply 4 is turned on to carry out the electrolytic reaction. Boric acid flocculants and oxygen are generated in the brine. The lithium ions in the brine are embedded in the lithium ion sieve 31, and the oxygen is discharged into the gas collection device 5. The clear water generated after the brine reaction is discharged from the drain outlet 15, and the boric acid flocculants are discharged into the sedimentation tank 7 through the flocculant discharge outlet 16 to recover boron ions.

[0042] Then, the cleaning pump is turned on to rinse the electrolytic cell 11, and then the lithium hydroxide solution is introduced into the electrolytic cell 11. The power supply 4 is turned on to carry out the electrolysis reaction, generating hydrogen gas. The lithium ions on the lithium ion sieve 31 undergo deintercalation to generate lithium hydroxide. The lithium hydroxide solution is concentrated, and the hydrogen gas is discharged into the gas collection device 5. When the lithium hydroxide solution in the electrolytic cell 11 reaches a certain concentration, the lithium hydroxide solution is discharged from the concentrate discharge port 17 into the concentrate storage tank 8 to recover lithium ions.

[0043] The following is passed Figure 3 The flowchart below illustrates the method for lithium extraction from brine. The lithium extraction apparatus uses the aforementioned lithium-ion extraction device.

[0044] like Figure 3 As shown, the method for extracting lithium from brine includes: lithium and boron separation step S1.

[0045] After brine is added to the electrolysis cell 11 through the feed inlet 14, the electrolysis module 91 in the control device 9 electrically connects the positive terminal of the power supply 4 to the titanium electrode 2 and the negative terminal to the electroactive membrane electrode 3 (see [link]). Figure 4 Open the oxygen exhaust valve 123, adjust the power supply voltage to 1~8V, and connect the power supply 4 to carry out the electrolysis reaction for 1 to 2 hours. Boric acid flocculants and oxygen are generated in the brine. Lithium ions in the brine are embedded in the lithium ion sieve 31, and oxygen is discharged into the oxygen storage tank 51 by the first blower 53. In this embodiment, the content of lithium ions in the added brine is 300 to 1500 ppm, the content of calcium ions is 1000 to 20000 ppm, the content of magnesium ions is 40000 to 90000 ppm, and the content of borate ions is 200 to 2000 ppm. It should be noted that ppm is a unit of concentration, that is, the mass of solute to the mass of solution in parts per million.

[0046] The following describes the lithium ion embedding sieve 31 in the brine.

[0047] Figure 4 This is a schematic diagram of the lithium-ion intercalation reaction state.

[0048] like Figure 4 As shown, since the positive terminal of power supply 4 is electrically connected to titanium electrode 2 and the negative terminal is electrically connected to electroactive membrane electrode 3, under the action of the electric field, oxygen evolution reaction occurs at titanium electrode 2. At the same time, borate ions in the brine migrate to titanium electrode 2 under the action of the electric field and undergo the following reaction:

[0049] 2H2O-4e - =O2↑+4H +

[0050] 4H + +4B(OH) 4- =4H3BO3↓+4H2O

[0051] The generated H3BO3 flocs settled to the bottom of electrolytic cell 11.

[0052] The electroactive membrane electrode 3 undergoes the reduction reaction shown below:

[0053] 8λ-MnO2+4e - + 4Li + =4LiMn2O4

[0054] In discharge step S2, after the lithium and boron separation is completed, the electrolysis module 91 opens the drain valve 151 and discharges the solution in the electrolysis cell 11 through the drain port 15.

[0055] In step S3, the electrolysis module 91 determines whether the boric acid flocs precipitated at the bottom of the electrolysis tank 11 have increased to a specified amount, i.e., whether the accumulated boric acid flocs affect the electrolysis reaction. If the boric acid flocs are below the specified amount, the electrolysis reaction can proceed again, returning to step S1, where brine is added to the electrolysis tank 11 again through the feed inlet 14 for further electrolysis. When the boric acid flocs reach the specified amount, the process proceeds to step S4, which involves discharging the boric acid flocs.

[0056] In the boric acid flocculant discharge step S4, the electrolysis module 91 shuts off the power supply 4 and opens the flocculant discharge valve 161 to discharge the flocculant products from the discharge port into the settling tank 7.

[0057] In cleaning step S5, the rinsing module 92 turns on the rinsing pump 62 to pump the cleaning water into the electrolytic cell 11, rinsing the electrolytic cell 11 and its internal titanium electrode 2 and electroactive membrane electrode 3 for 30 minutes, and then opens the drain valve 151 to discharge the rinsing water from the drain outlet to prevent residual solution from affecting the next reaction.

[0058] In regeneration step S6, lithium hydroxide solution, serving as the receiving liquid, is added to electrolytic cell 11 through feed inlet 14. Regeneration module 93 reverses the negative and positive terminals of power supply 4, connecting the negative terminal to titanium electrode 2 and the positive terminal to electroactive membrane electrode 3 (see [link to regeneration step S6]). Figure 5 Open the hydrogen exhaust valve 124, adjust the power supply voltage to 1~10V, connect the power supply 4, and carry out the reaction for 1~2 hours.

[0059] Under the influence of the electric field, lithium ions on the lithium ion sieve 31 undergo deintercalation and intercalation, entering the lithium hydroxide solution to increase the lithium ion concentration in the lithium hydroxide solution. The hydrogen gas generated in the lithium hydroxide solution is pumped into the hydrogen storage tank 52 by the second fan 54.

[0060] The following describes the lithium ion deintercalation / intercalation sieve 31.

[0061] Figure 5 This is a schematic diagram of the lithium-ion intercalation / deintercalation reaction.

[0062] like Figure 5 As shown, since the negative terminal of power supply 4 is electrically connected to titanium electrode 2 and the positive terminal is electrically connected to electroactive membrane electrode 3, under the action of the electric field, the electroactive membrane electrode 3 undergoes the following oxidation reaction:

[0063] 4 LiMn2O4-4e - =8λ-MnO2+4 Li + ,

[0064] Simultaneously, hydrogen evolution reaction also occurred at titanium electrode 2 as shown below:

[0065] 4H2O+4e - =2H₂↑+4OH -

[0066] The generated LiOH product causes the lithium hydroxide solution to become increasingly concentrated.

[0067] In the lithium hydroxide solution discharge step S7, when the lithium ions in the lithium hydroxide solution in the electrolytic cell 11 reach a certain concentration, the regeneration module 93 opens the concentrate discharge valve 171 to discharge the lithium hydroxide solution from the concentrate discharge port 17 into the concentrate storage tank 8.

[0068] The apparatus and method of the present invention have been described above. As can be seen from the above, in the present invention, brine is first electrolyzed in the electrolytic cell 11. Lithium ions in the brine are selectively extracted by intercalating into the lithium ion sieve 31 on the electroactive membrane electrode 3, while borate ions in the brine react with H+. + The separation of lithium ions and borate ions is achieved by combining precipitation in the form of flocculated products. This synergistic process significantly improves the efficiency of lithium extraction and boron removal.

[0069] Subsequently, a lithium hydroxide solution is added to the electrolytic cell 11, and the lithium ions in the lithium ion sieve 31 are deintercalated and regenerated, and the lithium ions are recovered into the lithium hydroxide solution.

[0070] This invention features a simple process that requires no additional chemical reagents, avoids secondary pollution, and generates high-value-added products such as oxygen, hydrogen, and flocculants like boric acid and lithium hydroxide. It solves the problems of cumbersome processes, high energy consumption, extractant loss, and pollution associated with existing methods for extracting lithium and boron ions from brine.

[0071] The following describes specific embodiments. Example

[0072] Titanium electrode 2 is a titanium mesh electrode, and the lithium ion sieve 31 on the electroactive membrane electrode 3 is a manganese-based lithium ion sieve (Li1-xMn2O4). 4 L of purified brine is added to the electrolytic cell 11, and the reaction is carried out at a power supply voltage of 4 V for 1 hour. Then, the solution in the electrolytic cell 11 is drained, and a cleaning solution is added for rinsing for 30 minutes. Finally, lithium hydroxide solution is pumped into the electrolytic cell 11, and the reaction is carried out at a power supply voltage of 8 V for 1 hour to obtain a concentrated lithium hydroxide solution.

[0073] The initial concentration of lithium ions in the brine was 500 ppm, and the initial concentration of borate ions was 3000 ppm.

[0074] The concentration of lithium ions in the treated solution was 25 ppm, the concentration of borate ions was 1000 ppm, and the amount of flocculent precipitate produced was approximately 3 g.

[0075] Calculations showed that the lithium ion extraction rate from the brine reached 95%, and the borate ion removal rate reached 67.6%. The lithium ion regeneration rate of the treated lithium hydroxide concentrate reached 98%. Example

[0076] Titanium electrode 2 is a titanium mesh electrode, and the lithium ion sieve 31 on the electroactive membrane electrode 3 is a manganese-based lithium ion sieve (Li1-xMn2O4). 4 L of purified brine is added to electrolytic cell 11, and the reaction is carried out at a power supply voltage of 1V for 2 hours. Then, the solution in electrolytic cell 11 is drained, and a cleaning solution is added for rinsing for 30 minutes. Finally, lithium hydroxide solution is pumped into electrolytic cell 11, and the reaction is carried out at a power supply voltage of 1V for 2 hours to obtain a concentrated lithium hydroxide solution.

[0077] The initial concentration of lithium ions in the brine was 500 ppm, and the initial concentration of borate ions was 3000 ppm.

[0078] The concentration of lithium ions in the treated solution was 25 ppm, the concentration of borate ions was 1000 ppm, and the amount of flocculent precipitate produced was approximately 3 g.

[0079] Calculations showed that the lithium ion extraction rate from the brine reached 95%, and the borate ion removal rate reached 67.6%. The lithium ion regeneration rate of the treated lithium hydroxide concentrate reached 98%. Example

[0080] Titanium electrode 2 is a titanium mesh electrode, and the lithium ion sieve 31 on the electroactive membrane electrode 3 is a manganese-based lithium ion sieve (Li1-xMn2O4). 4 L of purified brine is added to electrolytic cell 11, and the reaction is carried out at a power supply voltage of 8 V for 1 hour. Then, the solution in electrolytic cell 11 is drained, and a cleaning solution is added for rinsing for 30 minutes. Finally, lithium hydroxide solution is pumped into electrolytic cell 11, and the reaction is carried out at a power supply voltage of 10 V for 1 hour to obtain a concentrated lithium hydroxide solution.

[0081] The initial concentration of lithium ions in the brine was 500 ppm, and the initial concentration of borate ions was 3000 ppm.

[0082] The concentration of lithium ions in the treated solution was 25 ppm, the concentration of borate ions was 1000 ppm, and the amount of flocculent precipitate produced was approximately 3 g.

[0083] Calculations showed that the lithium ion extraction rate from the brine reached 95%, and the borate ion removal rate reached 67.6%. The lithium ion regeneration rate of the treated lithium hydroxide concentrate reached 98%. Example

[0084] Titanium electrode 2 is a titanium sheet electrode, and lithium ion sieve 31 on electroactive membrane electrode 3 is a vanadium-based lithium ion sieve (H2V3O8). 2 L of purified brine is added to electrolytic cell 11. The power supply voltage used during the separation process is 4 V, and the processing time is 2 h. Then, the solution in electrolytic cell 11 is drained, and the solution is rinsed with cleaning water for 30 min through a cleaning device.

[0085] The initial concentration of lithium ions in the brine was 600 ppm, and the initial concentration of borate ions was 1000 ppm.

[0086] The treated solution contained 25 ppm lithium ions and 200 ppm borate ions, and produced approximately 1.25 g of flocculated precipitate.

[0087] Calculations showed that the lithium ion extraction rate from the brine reached 96%, and the borate ion removal rate reached 80%. The lithium ion regeneration rate of the treated lithium hydroxide concentrate reached 97%. Example

[0088] The titanium electrode 2 is a titanium mesh electrode, and the lithium ion sieve 31 on the electroactive membrane electrode 3 is an iron-based lithium ion sieve 31 (Li1-xFePO4). 3 L of purified brine is added to the electrolytic cell 11. The power supply voltage used in the separation process is 4 V, and the processing time is 1 h.

[0089] The initial concentration of lithium ions in the brine was 500 ppm, and the initial concentration of borate ions was 2000 ppm.

[0090] The treated solution contained 25 ppm lithium ions and an initial 300 ppm borate ions. Approximately 3 g of flocculent precipitate was formed.

[0091] Calculations show that the lithium ion extraction rate in the brine reaches 95%, and the borate ion removal rate reaches 85%. The lithium ion regeneration rate in the treated lithium hydroxide concentrate reaches 99%.

[0092] It should be noted that 1-x refers to the number of moles of lithium ions that have been inserted or extracted.

[0093] It should be noted that the above embodiments are illustrative of the present invention and not restrictive of the present invention, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims.

Claims

1. A lithium extraction device from brine, characterized in that, It includes an electrolysis box (1), a titanium electrode (2), an electroactive membrane electrode (3), a power supply (4), a gas collection device (5), and a rinsing device (6). The electrolytic tank (1) has an electrolytic cell (11) inside. The top of the electrolytic tank (1) is provided with an air outlet (12) and a flushing outlet (13). The upper part of the side wall is provided with a feed inlet (14). The bottom of the side wall is provided with a drain outlet (15). The bottom of the electrolytic tank (1) is provided with a flocculant discharge outlet (16) and a concentrate discharge outlet (17). Multiple titanium electrodes (2) are arranged at certain intervals inside the electrolytic cell (11); The gas collecting device (5) is connected to the gas outlet (12); Multiple electroactive membrane electrodes (3) are disposed in an electrolytic cell (11). Each electroactive membrane electrode (3) is located on the side of the titanium electrode (2) and forms an electrode pair with the titanium electrode (2). A lithium ion sieve (31) is disposed on the electroactive membrane electrode (3). The power source (4) is electrically connected to the electroactive membrane electrode (3) and the titanium electrode (2), respectively; The rinsing device (6) and the rinsing port (13) are connected.

2. The brine lithium extraction device according to claim 1, characterized in that, It also includes a settling tank (7) and a concentrate storage tank (8). The sedimentation tank (7) is connected to the discharge outlet; The concentrate storage tank (8) is connected to the concentrate discharge port (17).

3. The brine lithium extraction device according to claim 1, characterized in that, The titanium electrode (2) is one of a titanium mesh electrode, a titanium sheet electrode, and a titanium plate electrode.

4. The brine lithium extraction device according to claim 1, characterized in that, The lithium ion sieve (31) is one of manganese-based lithium ion sieve, vanadium-based lithium ion sieve and iron-based lithium ion sieve.

5. The brine lithium extraction apparatus according to claim 4, characterized in that, The gas collection device (5) includes an oxygen storage tank (51) and a hydrogen storage tank (52). The outlet (12) includes an oxygen outlet (121) and a hydrogen outlet (122). The oxygen storage tank (51) has its inlet connected to its outlet (121). The inlet of the hydrogen storage tank (52) is connected to the outlet of the hydrogen (122); An oxygen exhaust valve (123) is provided on the oxygen outlet (121). A hydrogen exhaust valve (124) is provided on the hydrogen outlet (122).

6. The brine lithium extraction apparatus according to claim 5, characterized in that, A first blower (53) is provided at the oxygen outlet (121); A second fan (54) is provided at the hydrogen outlet (122).

7. The brine lithium extraction apparatus according to claim 6, characterized in that, The flushing device (6) includes a flushing pipe (61) and a flushing pump (62). One end of the flushing pipe (61) is connected to the flushing port (13), and the other end is connected to the flushing pump (62).

8. The brine lithium extraction apparatus according to claim 7, characterized in that, A filter screen (18) is provided at the drain outlet (15); A drain valve (151) is provided on the drain outlet (15); A floc discharge valve (161) is provided on the floc discharge port (16). A concentrate discharge valve (171) is provided on the concentrate discharge port (17).

9. A method for extracting lithium from brine, characterized in that, The brine lithium extraction apparatus according to any one of claims 1 to 8 comprises: In the lithium and boron separation step (S1), brine is added to the electrolytic cell (11), the positive electrode of the power supply (4) is electrically connected to the titanium electrode (2), and the negative electrode is electrically connected to the electroactive membrane electrode (3). The power supply (4) is turned on to carry out the electrolytic reaction, generating boric acid flocculents and oxygen. The lithium ions in the brine are embedded in the lithium ion sieve (31). In the discharge step (S2), after the lithium and boron separation is completed, the drain valve (151) is opened and the solution in the electrolytic cell (11) is discharged through the drain port (15); In the floc determination step (S3), it is determined whether the boric acid flocs deposited at the bottom of the electrolytic cell (11) have increased to a specified amount. If so, return to the lithium and boron separation step (S1); otherwise, proceed to the boric acid floc discharge step (S4). In the boric acid flocculant discharge step (S4), turn off the power (4), open the flocculant discharge valve (161), and discharge the flocculant into the sedimentation tank (7); Cleaning step (S5): Turn on the rinsing pump (62) to rinse the electrolytic cell (11), titanium electrode (2) and electroactive membrane electrode (3), and the rinsing water is discharged from the drain. In the regeneration step (S6), lithium hydroxide solution is added to the electrolytic cell (11). The negative electrode of the power supply (4) is electrically connected to the titanium electrode (2), and the positive electrode is electrically connected to the electroactive membrane electrode (3). The power supply (4) is turned on, so that the lithium ions on the lithium ion sieve (31) are deintercalated and enter the lithium hydroxide solution.

10. The method for extracting lithium from brine according to claim 9, characterized in that, In the lithium and boron separation step (S1), the power supply voltage is 1~8 V; In the regeneration step (S6), the power supply voltage is 1~10 V.

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