H of the embedded structure 1.6 Mn 1.6 O4@H2TiO3 composite lithium-ion sieve, its preparation and lithium extraction application

Abstract

The present invention belongs to the field of lithium extraction, and specifically relates to a H 1.6 Mn 1.6 O4@H2TiO3 composite lithium ion sieve, comprising H 1.6 Mn 1.6 O4 with a porous structure, and H2TiO3 embedded in the pore structure and surface-coated in H 1.6 Mn 1.6 O4. The present invention also includes the preparation of the material and its application in lithium extraction. The material described in the present invention has excellent lithium extraction capacity and cycle stability.

Description

Technical Field

[0001] This invention belongs to the field of lithium extraction, specifically relating to lithium-ion sieve materials for lithium extraction. Technical Background

[0002] The vigorous development of new energy industries such as lithium-ion batteries has led to a surge in demand for lithium both nationally and globally. It is projected that China's lithium demand will increase to 1.9 × 10⁻⁶ by 2025. 5 China's lithium resources account for 45% of the world's total lithium demand. A report by the U.S. Geological Survey on global mineral resources indicates that lithium resources in salt lake brines account for approximately 90% of the world's proven lithium resources. China's lithium resources are mainly divided into two categories: first, lithium ore, such as granite-type lithium deposits and pegmatite-type lithium deposits. Hard salt lithium deposits are characterized by low grade, high development difficulty, and high development costs; second, salt lake brines, which account for about 80% of my country's total lithium resources. Salt lakes rich in lithium resources in China include Zabuye Salt Lake in Tibet and Qinghai Salt Lake. Compared with lithium ore extraction, lithium extraction from salt lake brines has lower energy consumption and is more environmentally friendly, aligning with my country's current green environmental protection policies. However, because most of my country's salt lakes have a high lithium-magnesium ratio, high magnesium concentration, and low lithium concentration, this increases the difficulty of lithium extraction from salt lake brines. Currently, methods for extracting lithium from salt lake brine include membrane separation, precipitation, solvent extraction, and adsorption. Adsorption is more suitable for extracting lithium from low-concentration brine than other methods, both economically and environmentally. Adsorption methods mainly include inorganic and organic adsorption. Since organic adsorption is more difficult for low-valence ions, inorganic adsorption is preferred. Inorganic adsorption utilizes the Li in inorganic adsorbents... + The memory effect of lithium ions in salt lake brine can be separated from various ions (Na+, Na ... + Mg 2+ K + Ca 2+ Methods for selective adsorption of lithium ions (etc.). Compared with other adsorbents, lithium ion sieves are more effective at adsorbing Li-ion ions. + It has high selectivity and can effectively separate Li + It is used to prepare high-purity lithium products. In addition, lithium ion sieves have a series of advantages such as high theoretical adsorption capacity, low energy consumption and environmental friendliness.

[0003] Commonly used lithium-ion sieves mainly include H 1.33 Mn 1.67 O4, H 1.6 Mn 1.6 O4, H2TiO3, H4Ti5O 12Examples of lithium-ion sieves include λ-MnO2, etc. (see CN115970632A and CN117285105A for details). Among these, titanium-based lithium-ion sieves have a higher theoretical adsorption capacity, while manganese-based lithium-ion sieves possess a spinel structure with three-dimensional lithium diffusion channels. However, both manganese and titanium-based lithium-ion sieves have certain drawbacks: manganese-based lithium-ion sieves are prepared by acid washing, during which a small amount of Mn is introduced. 3+ The disproportionation reaction can lead to instability in the spinel structure and a decrease in cycle performance; while titanium-based lithium-ion sieves have the problem of slow adsorption rate. These problems limit the industrial use of lithium-ion sieves.

[0004] Generally, cations with small ionic radii (such as Fe) are used. 3+ Al 3+ Cr 3+ Mg 2+ Plasma doping can improve structural stability and reduce manganese dissolution, but it also leads to cell size shrinkage and reduced adsorption capacity. Various oxides (such as ZrO2, Fe3O4, and TiO2 oxides) can be used to form a coating on the surface of the lithium-ion sieve to reduce manganese dissolution and improve structural stability; however, these oxide-coated materials lack lithium adsorption capacity, resulting in a decrease in the adsorption performance of the lithium-ion sieve. Improving the manganese dissolution rate and structural stability of manganese-based lithium-ion sieves using basic doping and coating methods cannot simultaneously improve the adsorption capacity of the lithium-ion sieve. Summary of the Invention

[0005] To address the difficulty in simultaneously achieving optimal adsorption rate and stability in existing lithium-ion sieves, the primary objective of this invention is to provide an H-type sieve with an embedded structure. 1.6 Mn 1.6 The O4@H2TiO3 composite lithium ion sieve aims to provide a novel lithium ion sieve that balances excellent adsorption capacity, adsorption efficiency, and stability.

[0006] The second objective of this invention is to provide the H of the aforementioned embedded structure. 1.6 Mn 1.6 The preparation method of O4@H2TiO3 composite lithium-ion sieve aims to successfully prepare the material with the novel physicochemical structure and excellent performance.

[0007] A third objective of this invention is to provide an H utilizing the aforementioned embedded structure. 1.6 Mn 1.6 A method for lithium extraction using O4@H2TiO3 composite lithium ion sieves.

[0008] A type of H with interlocking structure 1.6 Mn 1.6 O4@H2TiO3 composite lithium-ion sieve, including porous H2O... 1.6 Mn 1.6 O4, and in H1.6 Mn 1.6 H2TiO3 is embedded in and coated on the surface of the porous structure of O4.

[0009] The novel material described in this invention has a watermelon-like structure, comprising a porous core (H... 1.6 Mn 1.6 O4), and H2TiO3 embedded in the porous structure of the core and coated on the surface of the core. In this invention, based on the aforementioned H 1.6 Mn 1.6 O4, H 1.6 Mn 1.6 The combination of O4 and the embedded-coating structure can unexpectedly achieve synergy, enabling the material to have excellent adsorption capacity, adsorption efficiency and stability.

[0010] In this invention, the H 1.6 Mn 1.6 The pore structure in O4 includes at least one of macropores, micropores, and mesopores, and is preferably a composite pore structure that includes two or more of macropores, micropores, and mesopores.

[0011] The present invention demonstrates that by employing the aforementioned porous structure with the aforementioned components and the combined use of the embedding-coating structure, synergistic effects can be further achieved, thereby further improving the lithium adsorption capacity, efficiency, and stability of the composite material.

[0012] In this invention, the H 1.6 Mn 1.6 The porosity of O4 is 10%–80%;

[0013] In this invention, the H of the embedded structure 1.6 Mn 1.6 The H2TiO3 content in the O4@H2TiO3 composite lithium ion sieve is 1-10 wt.%; preferably 1-5 wt.%.

[0014] In this invention, the porous H 1.6 Mn 1.6 The particle size of O4 is 1–10 μm; coated with H 1.6 Mn 1.6 The thickness of H2TiO3 on the O4 surface is 40–200 nm.

[0015] The present invention also provides an H-structure of the aforementioned embedding structure. 1.6 Mn 1.6 The preparation method of O4@H2TiO3 composite lithium-ion sieve involves a first hydrothermal reaction of porous Mn2O3 and a first lithium source to prepare porous lithium manganese oxide; and a second hydrothermal reaction and calcination of the porous lithium manganese oxide with a second lithium source and a titanium source to prepare porous Li. 1.6 Mn1.6 O4@Li2TiO3; after acid treatment, the H of the embedded structure is obtained. 1.6 Mn 1.6 O4@H2TiO3 composite lithium ion sieve.

[0016] The method described in this invention involves pre-preparing a porous lithium manganese oxide, then composited with Li₂TiO₃ on its pore structure and surface. After calcination, the lithium manganese oxide is converted into Li. 1.6 Mn 1.6 O4 is used to grow amorphous Li2TiO3 into Li2TiO3 crystals, thereby obtaining a new material with a novel embedded-coated structure, which can improve the lithium adsorption capacity, adsorption efficiency and stability of the prepared material.

[0017] In this invention, a manganese source, a carbon source, a pore-forming template agent, and a precipitant are heat-treated and then calcined in an oxygen-containing atmosphere to obtain the porous Mn2O3.

[0018] In this invention, the manganese source is a water-soluble manganese salt, such as at least one of manganese sulfate, manganese chloride, manganese acetate, and manganese nitrate.

[0019] Preferably, the carbon source pore-forming template agent includes at least one of a carbon microsphere hard template agent and a surfactant soft template agent; more preferably, it includes a carbon microsphere hard template agent and a surfactant soft template agent; further, the weight ratio of the carbon microsphere hard template agent to the surfactant soft template agent is 1:1 to 1:10; even more preferably, it is 1:3 to 6. Studies have shown that, under the composite pore-forming agent, especially at the aforementioned ratio, the physicochemical structure of the material can be further optimized, which is beneficial for the subsequent preparation of materials with embedded coating structures and helps to improve their lithium extraction effect.

[0020] The present invention demonstrates that, through the aforementioned composite template agent, materials with composite porous structures can be unexpectedly constructed, which facilitates the embedding and coating of Li2TiO3, helps to further improve the synergy of composition and structure, and can further improve the lithium adsorption capacity, efficiency and stability of the prepared materials.

[0021] In this invention, the carbon microsphere hard template agent can be conventional carbon particles.

[0022] In this invention, the D50 of the carbon microsphere hard template agent is 400nm to 800nm;

[0023] In this invention, the surfactant soft template agent includes, for example, at least one of PVP, CTAB, SDBS, etc.

[0024] In this invention, the precipitant is capable of dissociating CO3. 2-The substances may include, for example, one or more of hexamethylenetetramine, urea, and ammonium bicarbonate.

[0025] In this invention, the weight ratio of manganese source to carbon source pore-forming template agent is 1:1 to 10, further to 1:1.5 to 3; and even further to 1:2 to 2.5.

[0026] The amount of precipitant is not less than the theoretical amount for precipitating manganese source. Preferably, the molar ratio of precipitant to manganese source is greater than or equal to 2, and further, it is 10 to 50:1.

[0027] In this invention, the heat treatment process can be a liquid-phase heat treatment process. For example, the manganese source, carbon source pore-forming template agent, and precipitant are slurried with a solvent such as water and then subjected to heat treatment.

[0028] In this invention, the heat treatment temperature is 70–150°C, more preferably 80–130°C, and even more preferably 90–120°C;

[0029] In this invention, the heat treatment time is 5 to 25 hours, more preferably 10 to 20 hours;

[0030] In this invention, after heat treatment, a solid product is obtained through conventional solid-liquid separation, and then calcined in an oxygen-containing atmosphere to obtain the porous Mn2O3.

[0031] In this invention, the oxygen-containing atmosphere can be any atmosphere containing oxygen, such as air, oxygen, etc.

[0032] In this invention, the calcination temperature is 400–700°C, and can be further 500–600°C;

[0033] In this invention, the calcination time is 4 to 10 hours, and more specifically 6 to 8 hours.

[0034] In this invention, Mn2O3 and a first lithium source are dispersed in a solvent such as water, and then subjected to a first hydrothermal treatment to obtain the porous lithium manganese oxide.

[0035] In this invention, the first lithium source includes components capable of ionizing Li + It can be at least one of water-soluble salts and hydroxides, and may further be at least one of lithium chloride, lithium nitrate or lithium hydroxide;

[0036] In this invention, the molar ratio of Mn:Li in the first lithium source and the porous Mn2O3 is 1:1.2 to 1:2.2, and can be further 1:1.9 to 2.1;

[0037] In this invention, the first hydrothermal reaction temperature is 170–350°C, further can be 200–300°C, and even further can be 200–280°C;

[0038] In this invention, the time for the first hydrothermal reaction is 10-30 hours, and more preferably 15-25 hours;

[0039] In this invention, a first-calcined porous lithium manganese oxide, a second lithium source, and a titanium source are composited with a solvent such as water, followed by a second hydrothermal treatment. This allows Li₂TiO₃ to embed into the porous structure of the lithium manganese oxide and coat its surface. After calcination, Li₂TiO₃ is obtained. 1.6 Mn 1.6 O4@Li2TiO3.

[0040] In this invention, the titanium source includes at least one of TiO2, water-soluble titanium source Ti(SO4)2, and TiCl4;

[0041] In this invention, the Ti / Li molar ratio between the second lithium source and the titanium source is 1:1.2 to 1:2.2, and can be further 1:1.9 to 2.1;

[0042] In this invention, the weight ratio of titanium source to porous lithium manganese oxide is 0.01 to 0.1:1; more specifically, it is 0.03 to 0.06:1.

[0043] In this invention, the temperature of the second hydrothermal reaction is 170–350°C, more preferably 200–300°C, and even more preferably 200–280°C;

[0044] In this invention, the second hydrothermal time is 10-30 hours, and can be further 15-25 hours;

[0045] The roasting atmosphere is an oxygen-containing atmosphere, such as air or oxygen.

[0046] In this invention, the calcination temperature is 350–600°C, and can be further 400–550°C;

[0047] In this invention, the calcination time is 3 to 9 hours, and more specifically 4 to 6 hours.

[0048] In this invention, after calcination, the lithium adsorption sites can be released by conventional acid treatment to obtain the lithium ion sieve. In this invention, the acid treatment process can be conventional, for example, the acid solution in the acid treatment stage includes an inorganic strong acid solution.

[0049] The present invention also provides an H-structure of the aforementioned embedding structure. 1.6 Mn 1.6 The O4@H2TiO3 composite lithium ion sieve is used as an adsorbent to extract lithium from lithium-ion-containing solutions.

[0050] In this invention, H of the embedded structure described in this invention can be obtained based on conventional lithium extraction processes and methods. 1.6 Mn 1.6 O4@H2TiO3 composite lithium-ion sieves are used as adsorbents for lithium extraction.

[0051] In this invention, the lithium-ion-containing solution can be any lithium-containing solution with lithium extraction value, such as at least one of lithium-ion battery leachate and salt lake brine.

[0052] In this invention, the H of the embedded structure is... 1.6 Mn 1.6 After adsorption between the O4@H2TiO3 composite lithium ion sieve and the lithium-ion-containing solution, a lithium-loaded molecular sieve is obtained. Subsequently, after delithiation treatment, a lithium-rich solution is obtained, and the delithiated molecular sieve is recycled as an adsorbent for lithium extraction.

[0053] Beneficial effects

[0054] 1. This application provides a novel embedded structure for H 1.6 Mn 1.6 The O4@H2TiO3 composite lithium-ion sieve, based on the combination of components and structure, can achieve synergy and improve the lithium adsorption capacity, efficiency and stability of the material.

[0055] In this invention, the lithium-ion sieve prepared exhibits a lithium adsorption capacity of 40–60 mg·g in salt lake brine. -1 After 20 cycles, the lithium adsorption capacity in the salt lake brine remained at 30–55 mg·g. -1 The lithium adsorption capacity of the lithium-containing waste liquid generated after lithium extraction from spent lithium-ion batteries is 35–50 mg·g. -1 This lithium-ion sieve combines the advantages of cation doping and oxide coating modification methods, while optimizing the adsorption performance and cycling stability of the ion sieve, accelerating the mass transfer rate of titanium-based lithium-ion sieves. Compared with lithium-ion sieves reported in the literature, it has better cycling performance, higher adsorption capacity, higher cycling adsorption capacity retention rate, and more stable structure.

[0056] 2. This invention also provides a method for preparing the novel material, which innovatively introduces lithium manganese oxide into the hydrothermal synthesis of lithium titanate. Through optimization and joint control of conditions, lithium titanate is embedded in a manganese-based lithium ion sieve. Since the manganese-based lithium ion sieve has a three-dimensional lithium diffusion channel, it shortens the diffusion channel of lithium titanate. Simultaneously, the two-dimensional channels of lithium titanate increase lithium transport branches, forming a multi-dimensional, multi-directional three-dimensional lithium diffusion channel, greatly improving the lithium ion diffusion rate. Furthermore, the stable structure of lithium titanate acts as a coating layer for lithium manganese oxide, enhancing structural stability. Based on size threshold and memory effect, this composite adsorbent material not only improves adsorption capacity, adsorption rate, and enhances cycle performance, but also improves lithium-sodium separation performance, achieving targeted adsorption and lithium extraction from lithium-containing wastewater. Attached Figure Description

[0057] Appendix Figure 1 A schematic diagram of the entire experimental process.

[0058] Appendix Figure 2 SEM image of the porous Mn2O3 prepared in Example 1

[0059] Appendix Figure 3 The image shows the XRD pattern of the embedded titanium-manganese composite lithium-ion sieve precursor prepared in Example 1. Appendix Figure 4 SEM image of the uncoated manganese-based lithium-ion sieve precursor prepared in Comparative Example 1 Detailed Implementation

[0060] To address the issues of slow adsorption rates in titanium-based lithium-ion sieves and high dissolution rates in manganese-based lithium-ion sieves, this invention provides a titanium-manganese composite lithium-ion sieve material with a seed-core-shell structure, aiming to improve the material's structural stability and enhance its adsorption performance.

[0061] A titanium-manganese composite lithium-ion sieve with an embedded structure has a seed-core-shell structure, wherein the seed and shell layers are both made of H₂TiO₃, and the core layer material is H₂. 1.6 Mn 1.6 O4.

[0062] In the field of lithium-ion sieves, this invention provides a novel coating and doping modification method to overcome the slow adsorption rate and poor stability of existing lithium-ion sieve materials. It uses Li₂TiO₃ as the seed material and dops it with Li₂TiO₃. 1.6 Mn 1.6 In O4, Li2TiO3 is used as the coating shell, and after acid washing, H2TiO3 is used as the seed and shell, and H is doped and coated. 1.6 Mn 1.6 O4 is a lithium-ion sieve that integrates mutual coating, doping, and in-situ multiphase formation.

[0063] Li 1.6 Mn1.6 O4 is a thick watermelon seed with a three-dimensional network structure, Li + Choose one with good separation properties to act as Li + The host provides a large amount of Li to Li2TiO3. + To overcome mass transport resistance and improve adsorption rate and adsorption capacity; secondly, Li 1.6 Mn 1.6 O4 is abundantly embedded in the Li2TiO3 layer within the pores, shortening the Li2TiO3 diffusion path, creating new diffusion channels, increasing the diffusion flux, and significantly improving the Li2TiO3 adsorption kinetics; furthermore, Li2TiO3 is doped and embedded with Li 1.6 Mn 1.6 O4 layer, reducing Mn 2+ The content or acid leaching delithiation forms a lattice-type hydroxyl structure, improving structural stability; finally, the watermelon rind is a very thin Li2TiO3 layer, which acts as a Li 1.6 Mn 1.6 O4 coating layer to block acid and Li 1.6 Mn 1.6 Direct contact with O4 reduces manganese dissolution.

[0064] The mass of H2TiO3 is H 1.6 Mn 1.6 The loading of O4 is 1% to 10% by mass, and can be further 1% to 5%. At this loading, the adsorption capacity is greater, the structure is more stable, and the cycle performance is better.

[0065] The present invention discloses a method for preparing an optional composite lithium-ion sieve, comprising the following steps:

[0066] Step 1: Preparation of porous Mn2O3

[0067] After preparing carbon microspheres via hydrothermal glucose, the carbon microspheres and PVP were mixed and stirred for a certain period of time. Then, a precipitant and manganese salt were added to obtain a mixed solution. After stirring, MnCO3 / C composite material was synthesized by hydrothermal homogeneous precipitation. After washing, drying, and baking, porous Mn2O3 was prepared by high-temperature sintering.

[0068] Step 2: Preparation of porous lithium manganese oxide

[0069] The synthesized porous Mn2O3 and lithium source solution were mixed in liquid phase to form a suspension, which was then added to a high-pressure reactor for hydrothermal reaction to obtain lithium manganese oxide.

[0070] Step 3: Titanium-manganese composite lithium-ion sieve precursor (porous Li) 1.6 Mn 1.6 O4@Li2TiO3)

[0071] The titanium source, lithium source solution and lithium manganese oxide obtained in step two are mixed to form a homogeneous mixed solution, which is then added to a high-pressure reactor for hydrothermal reaction and calcined to obtain a composite lithium ion sieve precursor.

[0072] Step 4: Preparation of the embedded titanium-manganese composite lithium-ion sieve

[0073] The precursor obtained in step three was weighed and acid-treated, and then filtered, washed and dried to obtain a titanium-manganese composite lithium ion sieve with an embedded structure.

[0074] In this invention, the carbon spheres can be derived from existing commercial products or prepared using known methods, such as hydrothermal carbonization of a carbon source. The carbon source can be, for example, a small molecule sugar, and the hydrothermal carbonization temperature is, for example, 150–250°C. The hydrothermal carbonization time is, for example, 20–30 hours.

[0075] The following examples are intended to illustrate the invention and not to further limit it.

[0076] The coating amount of H2TiO3 refers to the mass of H2TiO3 in the prepared lithium-ion sieve. 1.6 Mn 1.6 Percentage of O4 mass.

[0077] The doping amount of H2TiO3 is determined according to the ratio of H2TiO3 to H... 1.6 Mn 1.6 The calculation is based on the molar ratio of O4.

[0078] In the following examples, the lithium-containing waste liquid generated after lithium extraction from spent lithium-ion batteries mainly contains Li. + Na + SO4 2- An aqueous solution, wherein Li + The concentration is 200 mg / L, Na + The concentration of SO4 is 46-60 g / L. 2- The concentration is 100 g / L.

[0079] The chemical composition of the salt lake brine used is shown in Table 1.

[0080] Table 1 shows the chemical composition of the salt lake brine used.

[0081]

[0082] Example 1

[0083] (1) Preparation of porous Mn2O3

[0084] 80g of glucose was dissolved in 500ml of deionized water to form a clear solution. The solution was then transferred to an autoclave and reacted at 170℃ for 24 hours. The solution was washed and filtered several times with deionized water and ethanol. The resulting precipitate was carbon spheres (D50 of 400nm to 800nm).

[0085] The carbon spheres and PVP were then mixed and stirred (the weight ratio of carbon spheres to PVP was 1:5; the total amount of both was 12g). The mixture was dispersed and stirred in 500mL of water. Then, 4.9g of manganese acetate and a precipitant (urea; the molar ratio of manganese salt to precipitant was 1:40) were added. After vigorous stirring for 1 hour, the mixture was transferred to an autoclave and hydrothermally reacted at 120℃ for 15 hours. After filtration, washing, and drying, the MnCO3 / C composite material was obtained. Porous Mn2O3 was obtained by calcination at 600℃ for 8 hours. SEM results are shown in [Figure number missing]. Figure 2 .

[0086] (2) Preparation of lithium manganese oxide

[0087] Weigh 17g LiOH·H2O and dissolve it in 500mL of deionized water. Slowly add the above porous Mn2O3, control the Li / Mn molar ratio to be 2.0:1, sonicate for 30min, and add the resulting mixed solution to an autoclave for hydrothermal reaction at 250℃ for 24h to obtain lithium manganese oxide.

[0088] (3) Preparation of titanium-manganese composite lithium ion sieve precursor with embedded structure

[0089] LiOH·H2O was weighed and dissolved in 500 mL of deionized water. 0.5 g of TiO2 powder and 10 g of lithium manganese oxide were slowly added, maintaining a Li / Ti molar ratio of 2.0:1. After sonication for 30 min, the resulting mixture was added to an autoclave and hydrothermally reacted at 250 °C for 24 h. After filtration, washing, and drying, the mixture was calcined at 500 °C for 6 h to obtain a titanium-manganese-doped composite lithium-ion sieve precursor (XRD see [reference]). Figure 3 ).

[0090] (4) Preparation of titanium-manganese composite lithium ion sieve with embedded structure

[0091] Weigh 6g of lithium-ion sieve precursor and add it to 1000mL of 0.5mol·L⁻¹ -1 The titanium-manganese composite lithium ion sieve with an embedded structure was obtained by acid leaching in HCl solution at 30°C for 4 hours, followed by filtration, washing, and drying.

[0092] (5) The ion sieve obtained in step (4) is crushed and sieved to obtain a titanium-manganese composite lithium ion sieve product with an embedded structure. The product is gray powder with a doping and coating amount of 5% of H2TiO3.

[0093] (6) Weigh 0.2 g of the embedded titanium-manganese composite lithium ion sieve and add it to 100 mL of Lop Nur old brine. The composition of the brine is shown in Table 1. The lithium concentration is low, at 222.2 mg·L⁻¹. -1 It exhibits a high magnesium-to-lithium ratio. After adsorption at 30℃ for 24 hours, the lithium adsorption capacity of the ion sieve is 53 mg·g⁻¹. -1 The lithium-adsorbed ion sieve was filtered, washed, and dried, and then added to a 0.5 mol·L⁻¹ solution. -1 The solution was acid-leached in HCl solution at 30°C for 4 hours. The above adsorption-acid washing steps were repeated, maintaining a solution-to-solid ratio of 0.167 L / g in each cycle. -1 The liquid-to-solid ratio during lithium adsorption is 0.5 L·g. -1 After 20 cycles, the corresponding adsorption capacity of the lithium-ion sieve was 42 mg·g⁻¹. -1 .

[0094] (7) Weigh 0.2g of the embedded titanium-manganese composite lithium-ion sieve and add it to 100mL of lithium-containing waste liquid generated after lithium extraction from waste lithium-ion batteries. The waste liquid mainly contains Li. + Na + SO4 2- An aqueous solution, wherein Li + The concentration was low, at 200 mg / L, Na + The concentration was 46-60 g / L, with a high lithium-to-sodium ratio. After adsorption at 30℃ for 24 h, the lithium adsorption capacity of the lithium ion sieve was 42 mg·g⁻¹. -1 The lithium-adsorbed ion sieve was filtered, washed, and dried, and then added to a 0.5 mol·L⁻¹ solution. -1 The solution was acid-leached in HCl solution at 30°C for 4 hours. The above adsorption-acid washing steps were repeated, maintaining a solution-to-solid ratio of 0.167 L / g in each cycle. -1 The liquid-to-solid ratio during lithium adsorption is 0.5 L·g. -1 After 20 cycles, the corresponding adsorption capacity of the lithium-ion sieve was 38 mg·g. -1 .

[0095] Example 2

[0096] Compared with Example 1, the only difference is that in step 1, the molar ratio of carbon spheres to PVP is 1:1, and the total amount of both is the same as the total amount of carbon spheres and PVP in Example 1. In step 3, 0.3g of TiO2 powder is added. All other operations and parameters are the same as in Example 1.

[0097] The test was conducted according to the method in Example 1, and the results are as follows:

[0098] For lithium extraction from brine:

[0099] The lithium adsorption capacity of the ion sieve is 50 mg·g. -1After 20 cycles, the adsorption capacity of the corresponding lithium-ion sieve was 43 mg·g. -1 .

[0100] Lithium extraction from lithium-containing waste liquid from batteries:

[0101] The lithium adsorption capacity of the ion sieve is 40 mg·g. -1 After 20 cycles, the adsorption capacity of the corresponding lithium-ion sieve was 35 mg·g. -1 .

[0102] Example 3

[0103] Compared with Example 1, the only difference is that carbon balls are missing in step 1, and the remaining amount of PVP is the same as the total amount of PVP + carbon balls in Example 1. All other operations and parameters are the same as in Example 1.

[0104] The test was conducted according to the method in Example 1, and the results are as follows:

[0105] For lithium extraction from brine:

[0106] The lithium adsorption capacity of the ion sieve is 46 mg·g. -1 After 20 cycles, the adsorption capacity of the corresponding lithium-ion sieve was 41 mg·g⁻¹. -1 .

[0107] Lithium extraction from lithium-containing waste liquid from batteries:

[0108] The lithium adsorption capacity of the ion sieve is 38 mg·g. -1 After 20 cycles, the adsorption capacity of the corresponding lithium-ion sieve was 32 mg·g⁻¹. -1 .

[0109] Example 4

[0110] Compared with Example 1, the only difference is that PVP is missing in step 1, and the amount of remaining carbon balls is the same as the total amount of PVP + carbon balls in Example 1. All other operations and parameters are the same as in Example 1.

[0111] The test was conducted according to the method in Example 1, and the results are as follows:

[0112] For lithium extraction from brine:

[0113] The lithium adsorption capacity of the ion sieve is 42 mg·g. -1 After 20 cycles, the adsorption capacity of the corresponding lithium-ion sieve was 38 mg·g. -1 .

[0114] Lithium extraction from lithium-containing waste liquid from batteries:

[0115] The lithium adsorption capacity of the ion sieve is 38 mg·g. -1After 20 cycles, the adsorption capacity of the corresponding lithium-ion sieve was 34 mg·g. -1 .

[0116] Example 5

[0117] Compared with Example 1, the only difference is that in step 1, the weight ratio of the total amount of carbon balls and PVP to manganese acetate is 2:1; the hydrothermal temperature is 100°C for 20 hours; and the calcination time is 500°C for 6 hours.

[0118] In step 2, the hydrothermal temperature is 200℃ and the time is 20 hours;

[0119] In step 3, the hydrothermal temperature is 200℃ and the time is 20h; the calcination temperature is 400℃ and the time is 4h.

[0120] Other operations and testing methods are the same as in Example 1:

[0121] For lithium extraction from brine:

[0122] The lithium adsorption capacity of the ion sieve is 51 mg·g. -1 After 20 cycles, the adsorption capacity of the corresponding lithium-ion sieve was 44 mg·g. -1 .

[0123] Lithium extraction from lithium-containing waste liquid from batteries:

[0124] The lithium adsorption capacity of the ion sieve is 41 mg·g. -1 After 20 cycles, the adsorption capacity of the corresponding lithium-ion sieve was 37 mg·g. -1 .

[0125] Comparative Example 1

[0126] Compared with Example 1, the only difference is that H2TiO3 embedding and coating modification are not performed. Specifically:

[0127] Lithium manganese oxide was prepared using the method in Example 1, and then calcined at 500°C for 6 hours to obtain a manganese-based lithium ion sieve precursor. 6 g of the manganese-based lithium ion sieve precursor was weighed and added to 1000 mL of 0.5 mol·L⁻¹ solution. -1 The manganese ion sieve was obtained by acid leaching in HCl solution at 30℃ for 4 hours, followed by filtration, washing, and drying; SEM results are shown in [Figure number missing]. Figure 4 .

[0128] The halogen and battery leaching solution were tested according to the method in Example 1, and the results were as follows:

[0129] For lithium extraction from brine:

[0130] The lithium adsorption capacity of the ion sieve is 31 mg·g. -1After 20 cycles, the adsorption capacity of the corresponding lithium-ion sieve was 26 mg·g. -1 .

[0131] Lithium extraction from lithium-containing waste liquid from batteries:

[0132] The lithium adsorption capacity of the ion sieve is 28 mg·g. -1 After 20 cycles, the adsorption capacity of the corresponding lithium-ion sieve was 24 mg·g. -1 .

[0133] Comparative Example 2

[0134] This comparative study only involves H2TiO3 titanium-based lithium-ion sieves, specifically:

[0135] (1) Preparation of titanium-based lithium-ion sieve precursor

[0136] Weigh out LiOH·H2O and dissolve it in 500mL of deionized water. Slowly add 20g of TiO2 powder, control the Li / Ti molar ratio to be 2.0:1, and sonicate for 30min. Then add the resulting mixed solution to an autoclave and hydrothermally react at 250℃ for 24h. After filtration, washing, and drying, calcine at 500℃ for 6h to obtain the titanium-based lithium ion sieve precursor.

[0137] (2) Preparation of titanium-based lithium-ion sieves

[0138] Weigh 6g of lithium-ion sieve precursor and add it to 1000mL of 0.5mol·L⁻¹ -1 The titanium-based lithium ion sieve was obtained by acid leaching in HCl solution at 30°C for 4 hours, followed by filtration, washing, and drying.

[0139] (3) The ion sieve obtained in step (2) is crushed and sieved to obtain a titanium-based lithium ion sieve product, which is white powder.

[0140] For lithium extraction from brine:

[0141] The lithium adsorption capacity of the ion sieve is 39 mg·g. -1 After 20 cycles, the adsorption capacity of the corresponding lithium-ion sieve was 32 mg·g⁻¹. -1 .

[0142] Lithium extraction from lithium-containing waste liquid from batteries:

[0143] The lithium adsorption capacity of the ion sieve is 35 mg·g. -1 After 20 cycles, the adsorption capacity of the corresponding lithium-ion sieve was 29 mg·g⁻¹. -1 .

[0144] Comparative Example 3

[0145] Compared with Example 1, the only difference is that in step 1, the carbon spheres and PVP are missing; all other operations and parameters are the same as in Example 1.

[0146] The test was conducted according to the method in Example 1, and the results are as follows:

[0147] For lithium extraction from brine:

[0148] The lithium adsorption capacity of the ion sieve is 34 mg·g. -1 After 20 cycles, the adsorption capacity of the corresponding lithium-ion sieve was 26 mg·g. -1 .

[0149] Lithium extraction from lithium-containing waste liquid from batteries:

[0150] The lithium adsorption capacity of the ion sieve is 30 mg·g. -1 After 20 cycles, the adsorption capacity of the corresponding lithium-ion sieve was 22 mg·g⁻¹. -1 .

[0151] Comparative Example 4

[0152] Compared to Example 1, the only difference is that the manganese and titanium ion sieves were not constructed with the aforementioned embedded coating structure, but were physically mixed. That is, the manganese ion sieve prepared in Comparative Example 1 and the titanium ion sieve prepared in Comparative Example 2 were physically mixed, with the Mn / Ti ratio being the same as the composite ion sieve in Example 1. All other operations and parameters were the same as in Example 1.

[0153] The test was conducted according to the method in Example 1, and the results are as follows:

[0154] For lithium extraction from brine:

[0155] The lithium adsorption capacity of the ion sieve is 36 mg·g. -1 After 20 cycles, the adsorption capacity of the corresponding lithium-ion sieve was 31 mg·g⁻¹. -1 .

[0156] Lithium extraction from lithium-containing waste liquid from batteries:

[0157] The lithium adsorption capacity of the ion sieve is 32 mg·g. -1 After 20 cycles, the adsorption capacity of the corresponding lithium-ion sieve was 25 mg·g. -1 .

Claims

1. An H-shaped embedded structure 1.6 Mn 1.6 O4@H2TiO3 composite lithium-ion sieve, characterized in that... H including porous structures 1.6 Mn 1.6 O4, and in H 1.6 Mn 1.6 H2TiO3 is embedded in and coated on the surface of the porous structure of O4; The H of the embedded structure 1.6 Mn 1.6 The H2TiO3 content in the O4@H2TiO3 composite lithium ion sieve is 1~10 wt.%; Encapsulated in H 1.6 Mn 1.6 The thickness of H2TiO3 on the O4 surface is 40~200nm.

2. The H of the embedded structure as described in claim 1 1.6 Mn 1.6 O4@H2TiO3 composite lithium-ion sieve, characterized in that... The H mentioned 1.6 Mn 1.6 The pore structure in O4 includes at least one of macropores, micropores, and mesopores.

3. The H of the embedded structure as described in claim 2 1.6 Mn 1.6 O4@H2TiO3 composite lithium-ion sieve, characterized in that... The H mentioned 1.6 Mn 1.6 O4 contains two or more types of composite pores, including macropores, micropores, and mesopores.

4. The H of the interlocking structure as described in claim 2 1.6 Mn 1.6 O4@H2TiO3 composite lithium-ion sieve, characterized in that... The H mentioned 1.6 Mn 1.6 The porosity of O4 is 10%~80%.

5. The H-structure of the embedding structure as described in any one of claims 1 to 4 1.6 Mn 1.6 O4@H2TiO3 composite lithium-ion sieve, characterized in that... The H of the embedded structure 1.6 Mn 1.6 The H2TiO3 content in the O4@H2TiO3 composite lithium ion sieve is 1~5 wt.%.

6. The H of the interlocking structure as described in any one of claims 1 to 4 1.6 Mn 1.6 O4@H2TiO3 composite lithium-ion sieve, characterized in that... H with porous structure 1.6 Mn 1.6 The particle size of O4 is 1~10μm.

7. An H-structure according to any one of claims 1 to 6 1.6 Mn 1.6 The preparation method of O4@H2TiO3 composite lithium ion sieve is characterized by, Porous lithium manganese oxide is prepared by subjecting porous Mn2O3 and a first lithium source to a first hydrothermal reaction; the porous lithium manganese oxide is then subjected to a second hydrothermal reaction and calcination with a second lithium source and a titanium source to prepare porous Li. 1.6 Mn 1.6 O4@Li2TiO3; after acid treatment, the H of the embedded structure is obtained. 1.6 Mn 1.6 O4@H2TiO3 composite lithium ion sieve.

8. The H of the interlocking structure as described in claim 7 1.6 Mn 1.6 The preparation method of O4@H2TiO3 composite lithium ion sieve is characterized by, The porous Mn2O3 was prepared by heat treatment of manganese source, carbon source, pore-forming template agent, and precipitant, followed by calcination in an oxygen-containing atmosphere.

9. The H of the interlocking structure as described in claim 8 1.6 Mn 1.6 The preparation method of O4@H2TiO3 composite lithium ion sieve is characterized by, The manganese source is a water-soluble manganese salt.

10. The H of the interlocking structure as described in claim 8 1.6 Mn 1.6 The preparation method of O4@H2TiO3 composite lithium ion sieve is characterized by, The carbon source pore-forming template agent includes at least one of carbon microsphere hard template agent and surfactant soft template agent.

11. The H of the embedded structure as described in claim 10 1.6 Mn 1.6 The preparation method of O4@H2TiO3 composite lithium ion sieve is characterized by, The D50 of the carbon microsphere hard template agent is 400nm~800nm.

12. The H of the embedded structure as described in claim 8 1.6 Mn 1.6 The preparation method of O4@H2TiO3 composite lithium ion sieve is characterized by, The precipitant mentioned is capable of dissociating CO3. 2- The substance.

13. The H of the embedded structure as described in claim 8 1.6 Mn 1.6 The preparation method of O4@H2TiO3 composite lithium ion sieve is characterized by, The weight ratio of manganese source and carbon source pore-forming template agent is 1:1~10.

14. The H of the interlocking structure as described in claim 13 1.6 Mn 1.6 The preparation method of O4@H2TiO3 composite lithium ion sieve is characterized by, The weight ratio of manganese source and carbon source pore-forming template agent is 1:1.5~3.

15. The H-structure of the embedding structure as described in claim 14 1.6 Mn 1.6 The preparation method of O4@H2TiO3 composite lithium ion sieve is characterized by, The weight ratio of manganese source and carbon source pore-forming template agent is 1:2~2.

5.

16. The H of the interlocking structure as described in claim 8 1.6 Mn 1.6 The preparation method of O4@H2TiO3 composite lithium ion sieve is characterized by, The heat treatment temperature is 70~150℃; the heat treatment time is 5~25h.

17. The H of the interlocking structure as described in claim 8 1.6 Mn 1.6 The preparation method of O4@H2TiO3 composite lithium ion sieve is characterized by, The heat treatment temperature is 80~130℃; the heat treatment time is 10~20h.

18. The H of the interlocking structure as described in claim 8 1.6 Mn 1.6 The preparation method of O4@H2TiO3 composite lithium ion sieve is characterized by, The calcination temperature is 400~700℃; The calcination time is 4 to 10 hours.

19. The H of the interlocking structure as described in claim 7 1.6 Mn 1.6 The preparation method of O4@H2TiO3 composite lithium ion sieve is characterized by, The first lithium source includes components capable of ionizing Li. + At least one of water-soluble salts and hydroxides.

20. The H of the embedded structure as described in claim 19 1.6 Mn 1.6 The preparation method of O4@H2TiO3 composite lithium ion sieve is characterized by, The first lithium source is at least one of lithium chloride, lithium nitrate, or lithium hydroxide.

21. The H of the embedded structure as described in claim 19 1.6 Mn 1.6 The preparation method of O4@H2TiO3 composite lithium ion sieve is characterized by, The molar ratio of Mn:Li in the first lithium source and the porous Mn2O3 is 1:1.2 to 1:2.

2.

22. The H of the embedded structure as described in claim 19 1.6 Mn 1.6 The preparation method of O4@H2TiO3 composite lithium ion sieve is characterized by, The temperature of the first hydrothermal reaction is 170~350℃.

23. The H of the embedded structure as described in claim 22 1.6 Mn 1.6 The preparation method of O4@H2TiO3 composite lithium ion sieve is characterized by, The temperature of the first hydrothermal reaction is 200~300℃.

24. The H of the interlocking structure as described in claim 22 1.6 Mn 1.6 The preparation method of O4@H2TiO3 composite lithium ion sieve is characterized by, The first hydrothermal reaction takes 10-30 hours.

25. The H of the embedded structure as described in claim 7 1.6 Mn 1.6 The preparation method of O4@H2TiO3 composite lithium ion sieve is characterized by, The titanium source includes at least one of TiO2, water-soluble titanium source Ti(SO4)2, and TiCl4.

26. The H of the embedded structure as described in claim 7 1.6 Mn 1.6 The preparation method of O4@H2TiO3 composite lithium ion sieve is characterized by, The Ti / Li molar ratio between the second lithium source and the titanium source is 1:1.2 to 1:2.2; The weight ratio of titanium source to porous lithium manganese oxide is 0.01~0.1:

1.

27. The H of the embedded structure as described in claim 7 1.6 Mn 1.6 The preparation method of O4@H2TiO3 composite lithium ion sieve is characterized by, The temperature of the second hydrothermal reaction is 170~350℃. The second hydrothermal time is 10~30 hours.

28. The H of the interlocking structure as described in claim 27 1.6 Mn 1.6 The preparation method of O4@H2TiO3 composite lithium ion sieve is characterized by, The temperature of the second hydrothermal reaction is 200~300℃; The second hydrothermal time is 15~25 hours.

29. The H of the embedded structure as described in claim 7 1.6 Mn 1.6 The preparation method of O4@H2TiO3 composite lithium ion sieve is characterized by, The roasting atmosphere is an oxygen-containing atmosphere; The roasting temperature is 350~600℃; The roasting time is 3 to 9 hours.

30. The H of the embedded structure as described in claim 7 1.6 Mn 1.6 The preparation method of O4@H2TiO3 composite lithium ion sieve is characterized by, The acid solution in the acid treatment stage includes inorganic strong acid solutions.

31. An H-structure according to any one of claims 1 to 6 1.6 Mn 1.6 O4@H2TiO3 composite lithium-ion sieve or H2TiO3 embedded structure prepared by the preparation method according to any one of claims 7-30 1.6 Mn 1.6 The application of O4@H2TiO3 composite lithium-ion sieve is characterized by... It is used as an adsorbent to extract lithium from lithium-ion-containing solutions.

32. The application as described in claim 31, characterized in that, The lithium-ion-containing solution includes at least one of the following: lithium-ion battery leachate and salt lake brine.

33. The application as described in claim 31 or 32, characterized in that, The H of the embedded structure 1.6 Mn 1.6 After adsorption between the O4@H2TiO3 composite lithium ion sieve and the lithium-ion-containing solution, a lithium-loaded molecular sieve is obtained. Subsequently, after delithiation treatment, a lithium-rich solution is obtained, and the delithiated molecular sieve is recycled as an adsorbent for lithium extraction.

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