Method and device for lithium extraction by redox adsorption

Abstract

The present application relates to a kind of oxidation-reduction adsorption extraction lithium method and device, method includes lithium extraction process and lithium insertion process, device includes electrolytic cell device, the electrolytic cell device includes anode chamber, cathode chamber, the anode chamber and cathode chamber are separated by diaphragm, lithium-rich lithium ion sieve is arranged in anode chamber, lithium-lean lithium ion sieve is arranged in cathode chamber, after power reaction, lithium in the lithium-rich lithium ion sieve of anode chamber is dissolved in anode liquid and forms lithium-lean lithium ion sieve, lithium-lean lithium ion sieve of cathode chamber and cathode liquid form first substance;The lithium insertion process is: the first substance is placed in the solution to be extracted lithium, first substance and lithium ion in the solution to be extracted lithium form lithium-rich lithium ion sieve;The lithium-rich lithium ion sieve formed in the lithium insertion process is released lithium ion to anode liquid by the lithium extraction process, and the extraction of lithium ion is completed.This method or device is simple in structure, easy to realize, and accelerates the extraction speed of lithium.

Description

Technical Field

[0001] This invention relates to a lithium extraction method and apparatus, and more particularly to a redox adsorption lithium extraction method and apparatus. Background Technology

[0002] With the explosive growth of the power battery industry, lithium has become an important resource. Lithium resources are mainly distributed in ores and water resources. Currently, ores are the main source of lithium supply, but their mining faces challenges such as high costs and significant environmental pollution. Salt lakes contain the majority of lithium reserves, and developing lithium extraction technology from salt lakes is crucial for ensuring the security of the lithium supply chain. Therefore, lithium extraction technology from salt lakes has attracted considerable attention.

[0003] Compared to traditional brine lithium extraction, raw brine lithium extraction has the following advantages: it can significantly increase lithium yield; shorten the lithium extraction cycle; reduce salt field construction and protect the ecology; and reduce water, electricity, and reagent consumption. Therefore, the development trend of lithium extraction is to extract lithium directly from raw brine. Salt lake lithium extraction technology is still in its development stage, and different extraction technologies are required depending on the specific characteristics of the salt lake. Currently, the main technical routes for salt lake lithium extraction in China include adsorption, extraction, membrane separation, solar pond methods, and electrochemical methods. Among these, adsorption and electrochemical methods have attracted much attention due to their suitability for raw brine lithium extraction. Adsorption lithium extraction has high production efficiency and a mature and reliable process. Its disadvantages are that acid washing is required during lithium desorption, leading to adsorbent loss and significant acid consumption (manganese-based and titanium-based adsorbents) or significant water consumption (aluminum-based adsorbents). Electrochemical lithium extraction methods can avoid the material loss caused by acid washing in traditional delithiation processes, enhance cycle performance, and are a low-energy, high-efficiency lithium extraction technology. However, electrochemical lithium extraction requires electrode materials with excellent selectivity, high lithium capacity, and long-term stability. Current electrochemical lithium extraction methods are limited by the structure of electrode materials, resulting in slow lithium extraction rates and low production efficiency. The system needs further optimization. Summary of the Invention

[0004] To address the problems existing in the above-mentioned lithium extraction technologies from salt lake brine, we propose an oxidation-reduction adsorption method. This technology avoids the problems of electrochemical and adsorption methods and is a highly efficient and green lithium extraction technology.

[0005] To achieve the above objectives, one approach adopted by the present invention is as follows: a redox adsorption lithium extraction method, comprising a delithiation process and a lithium intercalation process. The delithiation process is carried out in an electrolytic cell device, which includes an anode chamber and a cathode chamber separated by a diaphragm. A lithium-rich lithium-ion sieve is placed in the anode chamber, and a lithium-poor lithium-ion sieve is placed in the cathode chamber. After an electrical reaction, lithium in the lithium-rich lithium-ion sieve in the anode chamber desorbs from the sieve and dissolves in the anolyte, thus becoming a lithium-poor sieve. The lithium-poor sieve in the cathode chamber reacts with a certain component in the catholyte to form a first substance. The first substance is a solid substance formed by the lithium-poor sieve combining with a certain ion in the catholyte. When the first substance is placed in the lithium extraction solution, a spontaneous reaction occurs (i.e., no electrical current is required). After reacting with the lithium extraction solution, the first substance adsorbs lithium ions in the solution to form a lithium-rich lithium-ion sieve. This lithium-rich lithium-ion sieve is then placed back in the anode chamber during the delithiation process, and delithiation is performed in the chamber. By cyclically repeating the delithiation and lithium intercalation processes, the extraction and desorption of lithium ions can be achieved.

[0006] The following describes a specific loop format:

[0007] Cycle 1:

[0008] Delithiation process: The lithium-rich lithium-ion sieve in the anode chamber loses electrons and releases lithium ions to form a lithium-poor lithium-ion sieve;

[0009] In the cathode chamber, lithium-poor lithium ions gain electrons and embed into protons to form the first substance;

[0010] Lithium intercalation process: The first substance is placed in the lithium extraction solution to form a lithium-rich lithium ion sieve.

[0011] Cycle 2: The lithium-rich lithium-ion screen from Cycle 1 is placed in the anode chamber of the delithiation process, and the lithium-poor lithium-ion screen formed during the delithiation process in Cycle 1 is placed in the cathode chamber of the delithiation process. The delithiation process of this cycle is carried out. The lithium intercalation process is the same as in Cycle 1.

[0012] Lithium ions can be extracted from the original brine by repeatedly performing cycle one and cycle two.

[0013] As a preferred option, the anolyte in the delithiation process can be a lithium-containing solution or a solution of other ions that are easily separated from lithium ions. Lithium-containing solutions, such as lithium chloride and lithium sulfate, are preferred. The cathode solution is an acidic solution containing a large number of protons. The lithium ion sieve gains electrons during the reduction process and adsorbs protons in the cathode solution to form the first substance. The acidic solution is hydrochloric acid or sulfuric acid, etc. Using an acidic solution to react with the lithium ion sieve can accelerate the reaction process.

[0014] As a preferred option,

[0015] The lithium-rich lithium-ion sieve is a combination of one or more of the following:

[0016] —The lithium-rich lithium-ion sieve is lithium iron phosphate, and the lithium iron phosphate is one or a mixture of several of LiFePO4, LixMeyFePO4, LiFexMeyPO4, LiFePO4 / C, LixMeyFePO4 / C, and LiFexMeyPO4 / C, wherein Me is one or a mixture of several of Mn, Co, Mo, Ti, Al, Ni, and Nb, and 0 < x < 1, 0 < y < 1;

[0017] —The lithium-rich lithium-ion sieve is lithium manganese oxide, and the lithium manganese oxide is one or a mixture of several of LiMn2O4, LiMnO2, LixMey MnO2, LiMnxMeyPO4, LiMnO2 / C, LixMey MnO2 / C, and LiMnxMeyO2 / C, wherein Me is one or a mixture of several of Co, Mo, Ti, Al, Ni, and Nb, and 0 < x < 1, 0 < y < 1;

[0018] —The lithium-rich lithium-ion sieve is a ternary metal composite oxide, namely LiAxByC(1-xy)Oz, wherein A, B, and C are one or a mixture of several of Mn, Co, Mo, Ti, Al, Ni, and Nb, and 0 < x < 1, 0 < y < 1; the lithium-poor lithium-ion sieve is the material after delithiation of the lithium-rich lithium-ion sieve; the first material is the lithium-poor lithium-ion sieve and H + The resulting insoluble substance, if the lithium-rich lithium ion sieve is lithium manganese oxide, then the first substance is H₂. y MnO x .

[0019] As a preferred embodiment, the lithium-rich lithium-ion sieve of the present invention can be loaded onto a conductive substrate as an anode electrode to release lithium ions by interacting with the anolyte. Alternatively, it can be dispersed in the anolyte in powder form. When dispersed in the anolyte in powder form, it can directly transfer electrons with the anode electrode and release lithium ions by interacting with the anolyte. Alternatively, it can release lithium ions into the anolyte by transferring electrons with the anode electrode through an intermediate substance. The intermediate substance is an electron transfer substance, which is in powder form and dispersed in the anolyte.

[0020] Similarly, the lithium-poor lithium-ion sieve can be mounted on a conductive substrate as a cathode electrode, reacting with the catholyte to form a first substance. Alternatively, it can be dispersed in the catholyte as a powder. When dispersed in the catholyte as a powder, it can directly transfer electrons with the cathode electrode and react with the catholyte to form the first substance. Electron transfer can also be achieved through an electron-transferring substance dispersed in the catholyte as a powder. The electron-transferring substance can be single-stage or multi-stage. For example, the first electron-transferring substance reacts with the cathode electrode, then with a second electron-transferring substance, and then with a third electron-transferring substance. The third electron-transferring substance then interacts with the lithium-poor lithium-ion sieve to achieve electron transfer. When the lithium-rich or lithium-poor lithium-ion sieve is dispersed in the anolyte or catholyte as a powder, the reacted substance needs to be obtained through filtration.

[0021] As a preferred embodiment, the electron transport material in the anode chamber can be selected from substances with reversible redox properties such as TEMPO (2,2,6,6-tetramethylpiperidine oxide), nitrogen oxide radicals, and ferrocene, as well as oxidizing substances such as persulfates and hydrogen peroxide. The electron transport material in the cathode chamber can be selected from substances with reversible redox properties such as viologens, benzoquinones, and anthraquinones, as well as reducing substances such as sulfites, thiosulfates, and sulfides.

[0022] When a lithium-rich lithium-ion screen is loaded onto a conductive substrate, the conductive substrate is at least one of titanium mesh, graphite plate, carbon cloth, carbon paper, aluminum foil, and copper foil. When a lithium-poor lithium-ion screen is loaded onto a conductive substrate, the conductive substrate is at least one of titanium mesh, graphite plate, carbon cloth, carbon paper, aluminum foil, and copper foil.

[0023] As a preferred embodiment, the lithium intercalation process is carried out after adjusting the pH of the lithium extraction solution to between 9 and 14. An alkaline environment is beneficial for accelerating the ion exchange process. The displaced H+... + It can be neutralized by alkaline solutions, maintaining the H+ in the solution and ion sieve. + Concentration gradient accelerates the ion exchange process.

[0024] As a preferred embodiment, the lithium ion concentration in the lithium-containing solution is 0.1–2.5 mol / L. Using a lithium-containing solution to extract lithium helps simplify the lithium extraction process and ensure the purity of lithium. When the concentration of the lithium-containing solution is below 0.1 mol / L, it increases the device resistance, which is not conducive to the electrochemical reaction process. When the concentration is above 2.5 mol / L, it is not conducive to the extraction of lithium from the lithium-rich lithium ion sieve.

[0025] As a preferred embodiment, the cathode liquid is one or a combination of hydrochloric acid, sulfuric acid, and phosphoric acid. These acids react rapidly with lithium-poor lithium-ion sieves, which is beneficial for H+ ion exchange. + Combination with lithium-poor lithium-ion sieves.

[0026] The second approach is a redox adsorption lithium intercalation device corresponding to the method in the first approach, comprising a delithiation device and a lithium intercalation device. The delithiation device is an electrolytic cell device, comprising a cathode chamber and an anode chamber. The anode chamber contains a lithium-rich lithium-ion sieve and a cathode liquid, while the cathode chamber contains a lithium-poor lithium-ion sieve and an anode liquid. When energized, the lithium-rich lithium-ion sieve loses electrons and releases lithium ions into the anode liquid, while the lithium-poor lithium-ion sieve gains electrons and reacts with the cathode liquid to form a first substance. The lithium intercalation device contains a lithium extraction solution, and the first substance is placed in the lithium extraction solution in the lithium intercalation device to form a lithium-rich lithium-ion sieve.

[0027] As a preferred embodiment, the lithium intercalation device is the cathode chamber of the lithium removal device after power is turned off. After lithium removal is completed, the lithium extraction solution is introduced into the cathode chamber of the lithium removal device to complete the lithium extraction.

[0028] The beneficial effects of this invention include: the device or method of this invention is powered by electrochemistry in the delithiation stage and utilizes spontaneous reaction in the lithium insertion stage, resulting in low energy consumption, short process flow, and high selectivity. It can be used to extract lithium ions from raw brine, seawater, waste battery leachate, lithium precipitation mother liquor, and lithium extraction leachate from ore.

[0029] The device in this invention utilizes an acid solution to react with a lithium-poor lithium ion sieve to insert protons, and then the protons exchange ions with lithium ions in the lithium extraction solution to achieve lithium extraction. This process has high selectivity for lithium, increases the purity and efficiency of lithium extraction, and does not require acid washing or water washing, which is environmentally friendly.

[0030] The lithium-rich lithium-ion sieve and lithium-poor lithium-ion sieve selected in this invention have high selectivity for lithium, high capacity, and are insoluble in acid and alkali solutions, and can be recycled, thereby increasing lithium extraction efficiency and reducing operating costs.

[0031] This invention selects lithium-rich or lithium-poor lithium-ion sieves and disperses them in powder form in the corresponding electrolyte to increase the contact area between the lithium-ion sieve and the reactants in the solution, thereby improving the reaction process, increasing the adsorption capacity, and increasing the utilization rate of the lithium-ion sieve. By setting an intermediate electron transfer substance, electron transfer between the electrode and the lithium-ion sieve is realized. On the one hand, this reduces the difficulty of electron transport caused by the limited contact between the lithium-ion sieve and the electrode. On the other hand, it increases the controllability of the reaction process. The reaction process can be controlled by adjusting the composition or amount of the intermediate electron transfer substance. Attached Figure Description

[0032] Figure 1 Schematic diagram of the method and apparatus in this invention;

[0033] Figure 2 The method operation steps in this invention. Detailed Implementation

[0034] The present invention will be further explained in detail below with reference to the accompanying drawings and specific embodiments, but it should be understood that the scope of protection of the present invention is not limited to the specific implementation.

[0035] The redox adsorption lithium extraction method of this invention includes a delithiation process and a lithium intercalation process. In the lithium intercalation process, lithium ions in the solution to be extracted (hereinafter referred to as brine) are intercalated into a lithium-poor lithium-ion sieve to form a lithium-rich lithium-ion sieve. In the delithiation process, the lithium-rich lithium-ion sieve removes lithium ions under electrochemical action, thereby achieving lithium extraction. The lithium-rich lithium-ion sieve can be lithium manganese oxide, lithium iron phosphate, lithium manganese phosphate, lithium titanate, and lithium manganese iron phosphate, etc., while the lithium-poor lithium-ion sieve is the material remaining after the lithium-rich lithium-ion sieve has removed lithium ions.

[0036] The redox adsorption lithium extraction method of this invention can be implemented using a redox adsorption lithium extraction device, which includes a delithiation device and a lithium intercalation device. The delithiation device includes an electrolytic cell, which comprises a cathode chamber and an anode chamber. An ion exchange membrane is placed between the cathode and anode chambers. A cathode electrode and catholyte are placed in the cathode chamber, and an anode electrode and anolyte are placed in the anode chamber. A lithium-poor lithium-ion sieve can be loaded onto a conductive substrate to form an anode electrode, or it can be dispersed as powder in the catholyte. A lithium-rich lithium-ion sieve can be loaded onto a conductive substrate to form a cathode electrode, or it can be dispersed as powder in the anolyte. The lithium intercalation device can be a standalone device or it can be implemented using the delithiation device. That is, after the delithiation stage is completed, brine is introduced into the cathode chamber.

[0037] The following describes the lithium extraction steps of the device in this invention, using lithium manganese oxide as an example of a lithium-rich lithium-ion sieve. Figure 1 :

[0038] (1) Delithiation (Delithiation + Protonation): Lithium manganese oxide is loaded onto a conductive substrate as the anode electrode, and manganese oxide is loaded onto a conductive substrate as the cathode electrode. The anolyte is a lithium-containing solution, and the cathode solution is an acidic solution. The anode reaction after energization is as follows:

[0039] LiMnO x -e - →Li + +MnO x

[0040] The cathode reaction formula is:

[0041] MnO x +e - +yH + →H y MnO x

[0042] (2) Lithium intercalation (ion exchange lithium extraction): Stop the power supply, remove the anolyte and catholyte from the lithium extraction process, and introduce the lithium extraction solution into the cathode chamber. The lithium extraction solution here has been adjusted to an alkaline pH. The reaction that occurs at this time is as follows:

[0043] H y MnO x +yLiCl→Li y MnO x +yHCl

[0044] (3) The positive and negative electrodes of the battery are switched and the delithiation process continues. The lithium manganese oxide obtained in the lithium intercalation process is used as the anode electrode and the manganese oxide obtained in the delithiation process is used as the cathode electrode. The above steps are repeated.

[0045] It is worth mentioning that the lithium manganese oxide in the initial delithiation process can be derived from the raw material lithium manganese oxide, but the lithium manganese oxide after one cycle is obtained after the adsorption of lithium ions in the brine during the lithium intercalation process.

[0046] The present invention will be further described below by way of specific embodiments.

[0047] Example 1

[0048] Lithium manganese oxide (LiMnO4) in lithium-intercalated state x The slurry was prepared and coated onto a carbon cloth conductor to serve as the anode electrode; lithium-depleted manganese oxide (MnO) was used. x The slurry is prepared and coated onto a titanium mesh conductor to serve as the cathode electrode; polybenzimidazole is used as an anion exchange membrane and placed between the anode and cathode chambers. The lithium extraction steps are as follows: Figure 2 :

[0049] (1) Using simulated salt lake brine (initial raw brine) as the lithium extraction solution, the pH of the brine was adjusted to 10 using 1 mol / L sodium hydroxide solution.

[0050] (2) Pass 100 mL of 0.1 mol / L lithium chloride solution into the anode chamber and 100 mL of 0.5 mol / L hydrochloric acid solution into the cathode chamber.

[0051] (3) A peristaltic pump was used to control the flow rate of the anolyte and catholyte at 10 sccm, allowing for continuous circulation. The electrochemical reaction was carried out in constant current mode, with the electrochemical parameters set to a current of 10 mA / cm. 2 .

[0052] (4) After the reaction has been going on for 1 hour, stop the power supply, drain the cathode liquid and anolyte, and introduce 500 ml of simulated salt lake brine into the cathode chamber at a flow rate of 10 sccm.

[0053] (5) After the brine has been circulating for 1 hour, the solution in the cathode chamber is drained. At this time, the final residual liquid flowing out of the cathode chamber is lithium-poor solution.

[0054] (6) Swap the positions of the positive and negative electrode clamps of the electrolytic cell. Introduce 100 mL of 0.1 mol / L lithium chloride solution into the anode chamber as the lithium extraction solution, and introduce 100 mL of 0.5 mol / L hydrochloric acid solution into the cathode chamber. Then set the current to 10 mA / cm². 2 The extraction time was 1 hour. The lithium extraction solution flowing out of the anode chamber was lithium-rich. ICP testing of the lithium ion content in the lithium-poor and lithium-rich solutions can be used to evaluate the lithium extraction efficiency of the device. The test results are shown in Table 1.

[0055] Table 1. Lithium ion concentrations in the solution

[0056] Initial raw brine 0.07 50.0 5.0 Lithium-poor liquid 0.008 46.95 4.94 lithium-rich liquid 3.86 3.45 0.04

[0057] The table shows that the lithium ion content in the final residue after lithium extraction decreased significantly, with a lithium extraction rate of approximately 89%. The concentrations of sodium and magnesium ions in the brine remained essentially unchanged before and after lithium extraction, indicating that this method has high selectivity for lithium ions. The obtained lithium extract concentration was 3.86 g / L, demonstrating that this method can yield a high-concentration lithium extract. Directly obtaining a high-concentration lithium extract helps reduce water and energy consumption in the entire lithium extraction process.

[0058] Example 2

[0059] Both the cathode and anode electrodes are made of high-purity graphite, and the cathode and anode cells are separated by an anion exchange membrane. The anion exchange membrane is made of polybenzimidazole membrane material.

[0060] The anolyte was 100 ml of lithium chloride aqueous solution, in which lithium manganate and ferrocene powder were dispersed. The initial concentrations of each substance were: lithium manganate (Li... y MnO x The concentrations of the electrolyte were 0.1 mol / L ferrocene (Fc) and 0.15 mol / L lithium chloride. The cathode solution was 100 ml of hydrochloric acid solution, doped with manganese oxide (MnO). x The powders were manganese oxide 0.1 mol / L and methyl viologen powder, with the following concentrations: manganese oxide 0.1 mol / L, methyl viologen (MV... 2+ 0.15 mol / L, hydrochloric acid 0.1 mol / L.

[0061] During the delithiation process:

[0062] The cathode reaction formula is:

[0063] MV 2+ +e - →MV +

[0064] MV + +MnO x +yH + →H y MnO x +MV 2+

[0065] The anode reaction formula is:

[0066] Fc–e - →Fc +

[0067] Fc + +Li y MnO x →Li + +MnO x +Fc

[0068] The reaction formula during lithium intercalation is:

[0069] H y MnO x +yLiCl→Li y MnO x +yHCl

[0070] (1) Using simulated salt lake brine as the lithium extraction solution, the pH of the brine was adjusted to 10 using 1 mol / L sodium hydroxide solution.

[0071] (2) The prepared anolyte and catholyte are introduced into the anode chamber and cathode chamber respectively.

[0072] (3) A peristaltic pump was used to control the flow rate of the anolyte and catholyte at 10 sccm, allowing for continuous circulation. The electrochemical reaction was carried out in constant current mode, with the electrochemical parameters set to a current of 10 mA / cm. 2 .

[0073] (4) After reacting for 1 hour, the power was stopped, and the solutions in the cathode and anode chambers were drained. The solutions were then separated by centrifugation to obtain solid powder and a separate liquid. The solid separated from the anode chamber was lithium-poor MnO. x The corresponding liquid is lithium-rich solution.

[0074] (5) The solid separated from the cathode chamber was dispersed in 500 ml of Zabuye Salt Lake brine and stirred for 1 hour to extract lithium.

[0075] (6) The solution in step 5 is separated into solid and liquid by centrifugation to obtain lithium-poor solution and lithium manganese oxide powder with lithium intercalation.

[0076] (7) The substances obtained in steps 4 and 6 are recycled again, repeating step (1).

[0077] The test results are shown in Table 2:

[0078] Table 2. Lithium ion concentrations in the solution

[0079] Initial raw brine 0.07 50.0 5.0 Lithium-poor liquid 0.005 46.80 4.90 lithium-rich liquid 3.91 3.40 0.04

[0080] The table illustrates that the lithium ion content in the final residue (lithium-poor solution) after lithium extraction decreases significantly, with a lithium extraction rate of approximately 93%. The concentrations of sodium and magnesium ions in the brine remain essentially unchanged before and after lithium extraction, indicating that the method using powdered lithium ion sieves and electron transfer is more advantageous than electrode-based methods, further improving lithium ion selectivity. The resulting lithium extract (lithium-rich solution) has a concentration of 3.91 g / L, demonstrating that this method can yield a high-concentration lithium extract. Directly obtaining a high-concentration lithium extract helps reduce water and energy consumption in the entire lithium extraction process.

[0081] Example 3

[0082] Lithium iron phosphate was used as the ion sieve. The lithium-rich ion sieve was lithium iron phosphate (LiFePO4), and the lithium-poor ion sieve was iron phosphate (FePO4). The remaining materials and procedures were the same as in Example 1. The test results are shown in Table 3.

[0083] Table 3. Lithium ion concentrations in the solution

[0084] Initial raw brine 0.07 50.0 5.0 Lithium-poor liquid 0.015 47.75 4.83 lithium-rich liquid 3.50 3.00 0.02

[0085] The table shows that the lithium ion content in the final residue after lithium extraction decreases significantly, with a lithium extraction rate of approximately 80%. The concentrations of sodium and magnesium ions in the brine remain essentially unchanged before and after lithium extraction, indicating that this method has high selectivity for lithium ions. The obtained lithium extract concentration is 3.5 g / L, demonstrating that this method can yield a high-concentration lithium extract. Directly obtaining a high-concentration lithium extract helps reduce water and energy consumption in the entire lithium extraction process.

[0086] Example 4

[0087] The concentrations of lithium chloride in Example 1 were adjusted to 0.5 mol / L and 1.0 mol / L, respectively, with all other conditions remaining the same as in Example 1. The relevant test results are shown in Table 4.

[0088] Table 4. Lithium ion concentrations in the solution

[0089]

[0090] The table shows that changing the concentration of the lithium-containing solution resulted in good lithium extraction performance. When the lithium-containing solution concentration was 0.5 mol / L, the lithium extraction rate was 91%, and when the concentration was increased to 1.0 mol / L, the lithium extraction rate was 86%.

[0091] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for lithium extraction by redox adsorption, characterized in that: It includes a lithium delithiation process and a lithium intercalation process. The lithium delithiation process is carried out in an electrolytic cell device, which includes an anode chamber and a cathode chamber. The anode chamber and the cathode chamber are separated by a diaphragm. A lithium-rich lithium-ion sieve is set in the anode chamber and a lithium-poor lithium-ion sieve is set in the cathode chamber. After the reaction is carried out, the lithium in the lithium-rich lithium-ion sieve in the anode chamber dissolves in the anolyte to form a lithium-poor lithium-ion sieve. The lithium-poor lithium-ion sieve in the cathode chamber reacts with the catholyte to form the first substance. The delithiation process uses a lithium-containing solution as the anolyte and an H-containing solution as the anolyte. + The solution is a cathode solution; the lithium intercalation process is as follows: the first substance is placed in the lithium extraction solution, and the first substance reacts with the lithium ions in the lithium extraction solution to form a lithium-rich lithium ion sieve; the lithium-rich lithium ion sieve formed in the lithium intercalation process releases lithium ions into the anolyte through the delithiation process to complete the extraction of lithium ions.

2. The redox adsorption lithium extraction method according to claim 1, characterized in that: The lithium-rich lithium-ion sieve is a combination of one or more of the following: —The lithium-rich lithium-ion sieve is lithium iron phosphate, and the lithium iron phosphate is one or a mixture of several of LiFePO4, LixMeyFePO4, LiFexMeyPO4, LiFePO4 / C, LixMeyFePO4 / C, and LiFexMeyPO4 / C, wherein Me is one or a mixture of several of Mn, Co, Mo, Ti, Al, Ni, and Nb, and 0 < x < 1, 0 < y < 1; —The lithium-rich lithium-ion sieve is lithium manganese oxide, and the lithium manganese oxide is one or a mixture of several of LiMn2O4, LiMnO2, LixMey MnO2, LiMnxMeyPO4, LiMnO2 / C, LixMey MnO2 / C, and LiMnxMeyO2 / C, wherein Me is one or a mixture of several of Co, Mo, Ti, Al, Ni, and Nb, and 0 < x < 1, 0 < y < 1; —The lithium-rich lithium-ion sieve is a ternary metal composite oxide, which is LiAxByC(1-xy)Oz, wherein A, B, and C are one or a mixture of several of Mn, Co, Mo, Ti, Al, Ni, and Nb, and 0 < x < 1, 0 < y < 1. The lithium-poor lithium ion screen is the material after the lithium-rich lithium ion screen has been delithiated. The first substance is a lithium-poor lithium-ion sieve and H + The substance formed after combination.

3. The redox adsorption lithium extraction method according to claim 1, characterized in that: The lithium-rich lithium-ion sieve is loaded on a conductive substrate as an anode electrode or dispersed in the anolyte in powder form. When dispersed in the anolyte in powder form, it directly or indirectly interacts with the anode electrode, loses electrons, and releases lithium ions. The lithium-poor lithium-ion sieve is loaded on a conductive substrate as a cathode electrode or dispersed in catholy liquid in powder form. When dispersed in catholy liquid in powder form, it directly or indirectly interacts with the cathode electrode to obtain electrons and form the first substance.

4. The redox adsorption lithium extraction method according to claim 3, characterized in that: The lithium-rich lithium-ion sieve is dispersed in the anolyte in powder form, and at least one anolyte electron transfer material is also dispersed in the anolyte. The lithium-rich lithium-ion sieve transfers electrons to the anode electrode through the anolyte electron transfer material. The lithium-poor lithium-ion sieve is dispersed in catholyte in powder form, and at least one cathode electron transfer material is also dispersed in the catholyte. The lithium-poor lithium-ion sieve transfers electrons to the cathode electrode through the cathode electron transfer material.

5. The redox adsorption lithium extraction method according to claim 4, characterized in that: The cathode electron transport material satisfies one or more of the following: —The cathode electron transfer material is a substance with reversible redox properties; —The cathode electron-transferring substance is a reducing substance; —The cathode electron transport material is one or more of the following: viologens, benzoquinones, anthraquinones, sulfites, thiosulfates, and sulfides. The anodic electron transport material satisfies one or more of the following: —The anodic electron-transferring material is a substance with reversible redox properties; —The anode electron transfer substance is an oxidizing substance; —The anodic electron transport substances are TEMPO, nitrogen and oxygen free radicals, ferrocene, persulfate, and hydrogen peroxide.

6. The redox adsorption lithium extraction method according to claim 3, characterized in that: The conductive substrate is at least one of titanium mesh, graphite plate, carbon cloth, carbon paper, aluminum foil, and copper foil.

7. The redox adsorption lithium extraction method according to claim 1, characterized in that: The lithium intercalation process is carried out after adjusting the pH value of the lithium extraction solution to between 9 and 14.

8. The redox adsorption lithium extraction method according to claim 1, characterized in that: The cathode solution is one or more of hydrochloric acid, sulfuric acid, and phosphoric acid; the lithium ion concentration in the lithium-containing solution is 0.1~2.5 mol / L.

9. A redox adsorption lithium intercalation device, characterized in that: It includes a lithium removal device and a lithium insertion device. The lithium removal device is an electrolytic cell device, including a cathode chamber and an anode chamber. The anode chamber is equipped with a lithium-rich lithium ion sieve and a cathode liquid, and the cathode chamber is equipped with a lithium-poor lithium ion sieve and an anode liquid. When energized, the lithium-rich lithium ion sieve loses electrons and releases lithium ions into the anode liquid, and the lithium-poor lithium ion sieve gains electrons and reacts with the cathode liquid to form a first substance. The anolyte is a lithium-containing solution, and the cathode solution is a H-containing solution. + The solution; the lithium intercalation device contains a lithium solution to be extracted, and the first substance is placed in the lithium solution to be extracted in the lithium intercalation device to form a lithium-rich lithium ion sieve.

10. The redox adsorption lithium intercalation device according to claim 9, characterized in that: The lithium intercalation device is the cathode chamber in the lithium removal device after power is turned off. After lithium removal is completed, the lithium extraction solution is introduced into the cathode chamber of the lithium removal device to complete the lithium extraction.

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