Silica lithium ion sieve composite material and its preparation method

Abstract

This application discloses a silica-lithium ion sieve composite material and its preparation method. The preparation method includes mixing polyethylene glycol and concentrated nitric acid to obtain mixture A; adding tetraethyl orthosilicate to mixture A under ice-water bath conditions and continuously stirring to obtain mixture B; heating mixture B under sealed conditions to obtain a gel; mixing the gel with a lithium ion sieve, then extruding and granulating, and subsequently drying and calcining to obtain the silica-lithium ion sieve composite material. The preparation method of this application mixes a porous gel structure with a lithium ion sieve, then wet-blends, extrudes, granulates, and calcines. The silica gel binds the lithium ion sieve powder together while retaining the porous structure of the gel, resulting in a composite material with a honeycomb-like porous network framework. The preparation method is simple, efficient, and can greatly retain the adsorption sites of the lithium ion sieve, making the lithium ion sieve easy to dispose of and recycle.

Description

Technical Field

[0001] This application belongs to the field of composite material technology, specifically relating to a silica lithium ion sieve composite material and its preparation method. Background Technology

[0002] Lithium (Li) plays a crucial role in the new energy field. With the rapid development of new energy vehicles and energy storage technologies, the demand for lithium resources is growing at an unprecedented rate. China's salt lakes are rich in lithium resources, with approximately 70% of the lithium resources existing in the salt lake water. Compared with traditional ore extraction, extracting lithium from salt lake brine has the advantages of lower cost and relatively simpler operation.

[0003] Due to the presence of Li in the salt lake brine + Na + K + Ca 2+ Mg 2+ The presence of multiple ions, including magnesium and lithium ions, and the high magnesium-to-lithium ratio in most salt lake brines, makes separation difficult using traditional precipitation and solar pond methods. Adsorption methods, however, are limited by their affinity for Li. + It has high selectivity, is simple to operate, and is environmentally friendly, making it widely used in lithium-ion recovery from salt lake brine. However, lithium-ion sieves used for lithium-ion recovery are in powder form, which is prone to physical loss during the adsorption and recovery process, hindering their reuse. Summary of the Invention

[0004] The purpose of this application is to provide a silica lithium ion sieve composite material and its preparation method, so as to solve the technical problem that the lithium ion sieve used for lithium ion recovery in the prior art is in powder form, which is prone to physical loss during the adsorption and recovery process and is not conducive to repeated use.

[0005] To achieve the above objectives, one technical solution adopted in this application is:

[0006] A method for preparing a silica lithium-ion sieve composite material is provided, comprising:

[0007] Polyethylene glycol and concentrated nitric acid were mixed to obtain mixture A;

[0008] Under ice-water bath conditions, tetraethyl orthosilicate was added to the mixture A and stirred continuously to obtain mixture B;

[0009] Mixture B was heated under sealed conditions to obtain a gel;

[0010] The gel was mixed with a lithium-ion sieve, then extruded and granulated, and subsequently dried and calcined to obtain a silica-lithium-ion sieve composite material.

[0011] In one or more embodiments, the mass concentration of polyethylene glycol in the mixture A is 0.05 to 0.06 g / mL, and the volume ratio of concentrated nitric acid to the mixture A is (0.05 to 0.06):1.

[0012] In one or more embodiments, the polyethylene glycol has a molecular weight of 11,000 to 3,000,000.

[0013] In one or more embodiments, the mass concentration of tetraethyl orthosilicate in the mixture B is 1.2 to 1.3 g / mL.

[0014] In one or more embodiments, the step of heating the mixture B in a sealed state to obtain a gel specifically involves heating at 60°C for 2 hours.

[0015] In one or more embodiments, in the step of mixing the gel with the lithium ion sieve, the mass ratio of the gel to the lithium ion sieve is (0.5 to 20):1.

[0016] In one or more embodiments, in the step of mixing the gel with a lithium-ion sieve, then extruding and granulating it, and subsequently drying and calcining it to obtain a silica-lithium-ion sieve composite material, the calcination temperature is 500–700°C.

[0017] In one or more embodiments, the lithium-ion sieve is H 1.33 Mn 1.67 O4, H 1.6 Mn 1.6 O4, H2TiO3, H4Ti5O 12 One or more combinations of λ-MnO2.

[0018] To achieve the above objectives, another technical solution adopted in this application is:

[0019] A silica lithium ion sieve composite material prepared by the preparation method described in any of the above embodiments is provided.

[0020] The advantages of this application, which differ from existing technologies, are:

[0021] The preparation method of this application mixes a porous gel structure with a lithium ion sieve, then wet-gel co-extrusion granulation, and then calcining the silica gel to bind the lithium ion sieve powder together. At the same time, it can retain the porous structure of the gel to obtain a composite material with a honeycomb porous network skeleton. The preparation method is simple and efficient, and can greatly retain the adsorption sites of the lithium ion sieve, making the lithium ion sieve easy to put into use and easy to recycle.

[0022] The silica lithium-ion sieve composite material of this application is made of silica gel bonded lithium-ion sieve. The composite material contains a large number of voids, which ensures that the adsorption sites of the lithium-ion sieve are fully exposed, so that the composite material has a high adsorption capacity, with the highest adsorption capacity reaching 29.75 mg / g in salt lake brine and the highest adsorption capacity reaching 10.43 mg / g in seawater. Attached Figure Description

[0023] Figure 1 This is a schematic flowchart of one embodiment of the preparation method of the silica lithium-ion sieve composite material of this application;

[0024] Figure 2 This is an image of the silica-lithium ion sieve composite material prepared in Example 1. Detailed Implementation

[0025] The present application will now be described in detail with reference to the embodiments shown in the accompanying drawings. However, these embodiments do not limit the present application, and any structural, methodological, or functional modifications made by those skilled in the art based on these embodiments are included within the protection scope of the present application.

[0026] As in the background technology, since the lithium ion screen is in powder form, it is prone to physical loss during the recovery process when applied to the adsorption of lithium ions in salt lake brine, which affects the recovery efficiency of lithium ions and also causes the loss of the lithium ion screen, resulting in significant economic losses.

[0027] To address this issue, the applicant developed a silica-lithium ion sieve composite material. This composite material can effectively fix the lithium ion sieve and retain its adsorption sites, thereby avoiding physical losses during lithium ion sieve adsorption and recovery while ensuring the adsorption effect of the ion sieve.

[0028] Specifically, please refer to Figure 1 , Figure 1 This is a schematic flowchart of one embodiment of the preparation method of the silica lithium ion sieve composite material of this application.

[0029] The preparation method includes:

[0030] S100. Polyethylene glycol and concentrated nitric acid are mixed to obtain mixture A.

[0031] S200. Under ice-water bath conditions, add tetraethyl orthosilicate to mixture A and stir continuously to obtain mixture B.

[0032] Specifically, mixture A includes polyethylene glycol as a pore-forming agent and concentrated nitric acid as a catalyst. By adding tetraethyl orthosilicate to mixture A and stirring thoroughly, polyethylene glycol and tetraethyl orthosilicate can be thoroughly mixed. At the same time, concentrated nitric acid acts as a catalyst to effectively promote the hydrolysis reaction of tetraethyl orthosilicate, thereby forming a homogeneous and transparent solution.

[0033] In one application scenario, the molecular weight of polyethylene glycol can be 11,000 to 3,000,000, and the mass concentration of polyethylene glycol in mixture A can be 0.05 to 0.06 g / mL, thereby ensuring sufficient pore-forming effect.

[0034] In one application scenario, the volume ratio of concentrated nitric acid to mixture A is (0.05~0.06):1, thereby ensuring that tetraethyl orthosilicate can be fully catalytically hydrolyzed.

[0035] In one application scenario, the mass concentration of tetraethyl orthosilicate in mixture B can be 1.2–1.3 g / mL, thereby ensuring the structural stability of the subsequent composite material.

[0036] S300. Heat the mixture B under sealed conditions to obtain a gel.

[0037] When polyethylene glycol and tetraethyl orthosilicate are thoroughly mixed and heated under sealed conditions, a gel structure with uniformly distributed pores can be obtained.

[0038] In one application scenario, heating can specifically refer to heating at 60°C for 2 hours.

[0039] S400: The gel is mixed with a lithium-ion sieve, then extruded and granulated, and subsequently dried and calcined to obtain a silica-lithium-ion sieve composite material.

[0040] The porous gel structure is mixed with a lithium-ion sieve, followed by wet gel co-extrusion granulation, and then the silica gel is dried and calcined to bind the lithium-ion sieve powder together. At the same time, the porous structure of the gel is preserved to obtain a composite material with a honeycomb porous network skeleton. The preparation method is simple and efficient, and can greatly preserve the adsorption sites of the lithium-ion sieve, making the lithium-ion sieve easy to put into use and easy to recycle.

[0041] In one application scenario, the lithium-ion sieve can be H 1.33 Mn 1.67 O4, H 1.6 Mn 1.6 O4, H2TiO3, H4Ti5O 12 One or more combinations of λ-MnO2.

[0042] In one application scenario, in order to ensure that the lithium ion sieve can be fully dispersed inside the pores of the gel, and at the same time ensure that the adsorption sites of the lithium ion sieve are preserved, the mass ratio of gel to lithium ion sieve can be (0.5~20):1.

[0043] In one application scenario, an extruder can be used for extrusion granulation, and the calcination temperature can be 500–700℃.

[0044] The technical solution of this application will be further described in detail below with reference to specific embodiments.

[0045] Example 1:

[0046] A solution was prepared by mixing 0.4 g of polyethylene glycol with a molecular weight of 70,000, 6.4 mL of deionized water, and 0.397 mL of concentrated nitric acid. Then, under ice-water bath conditions, the solution was stirred and 8.75 g of tetraethyl orthosilicate was slowly added. Stirring was continued for 5 minutes to obtain a homogeneous and transparent solution.

[0047] The solution was transferred into a sealable container and allowed to gel at 60°C for 2 hours under sealed conditions.

[0048] Gel and lithium ion sieve H 1.33 Mn 1.67 O4 was mixed at a mass ratio of 10:1, extruded through an extruder, granulated, dried at 60°C, and finally calcined at 600°C to obtain a silica-lithium ion screen composite material.

[0049] Example 2

[0050] A solution was prepared by mixing 0.4 g of polyethylene glycol with a molecular weight of 11000, 6.4 mL of deionized water, and 0.397 mL of concentrated nitric acid. Then, under ice-water bath conditions, the solution was stirred and 8.75 g of tetraethyl orthosilicate was slowly added. Stirring was continued for 5 minutes to obtain a homogeneous and transparent solution.

[0051] The solution was transferred into a sealable container and allowed to gel at 60°C for 2 hours under sealed conditions.

[0052] Gel and lithium ion sieve H 1.6 Mn 1.6 O4 was mixed at a mass ratio of 8:1, extruded through an extruder, granulated, dried at 60°C, and finally calcined at 600°C to obtain a silica-lithium ion screen composite material.

[0053] Example 3

[0054] A solution was prepared by mixing 0.4 g of polyethylene glycol with a molecular weight of 500,000, 6.4 mL of deionized water, and 0.397 mL of concentrated nitric acid. Then, under ice-water bath conditions, the solution was stirred and 8.75 g of tetraethyl orthosilicate was slowly added. Stirring was continued for 5 minutes to obtain a homogeneous and transparent solution.

[0055] The solution was transferred into a sealable container and allowed to gel at 60°C for 2 hours under sealed conditions.

[0056] Gel and lithium ion sieve H2T i O3 was mixed at a mass ratio of 15:1, extruded through an extruder, granulated, dried at 60°C, and finally calcined at 600°C to obtain a silica-lithium ion screen composite material.

[0057] Example 4

[0058] Mix 0.4g of polyethylene glycol with a molecular weight of 11000, 6.4mL of deionized water, and 0.397mL of concentrated nitric acid to prepare a solution. Then, under ice-water bath conditions, stir the solution and slowly add 8.75g of tetraethyl orthosilicate. Continue stirring for 5 minutes to obtain a homogeneous and transparent solution.

[0059] The solution was transferred into a sealable container and allowed to gel at 60°C for 2 hours under sealed conditions.

[0060] The gel was mixed with a lithium ion sieve H4Ti5O 12 The mixture was prepared by mixing at a mass ratio of 20:1, extruding through an extruder, granulating, drying at 60°C, and finally calcining at 600°C to obtain a silica lithium ion screen composite material.

[0061] Example 5

[0062] A solution was prepared by mixing 0.4 g of polyethylene glycol with a molecular weight of 20000, 6.4 mL of deionized water, and 0.397 mL of concentrated nitric acid. Then, under ice-water bath conditions, the solution was stirred and 8.75 g of tetraethyl orthosilicate was slowly added. Stirring was continued for 5 minutes to obtain a homogeneous and transparent solution.

[0063] The solution was transferred into a sealable container and allowed to gel at 60°C for 2 hours under sealed conditions.

[0064] The gel was mixed with lithium-ion sieve λ-MnO2 at a mass ratio of 10:1, extruded through an extruder, granulated, dried at 60°C, and finally calcined at 600°C to obtain a silica lithium-ion sieve composite material.

[0065] Example of effect 1:

[0066] Please see Figure 2 , Figure 2This is an image of the silica lithium-ion sieve composite material prepared in Example 1. This silica lithium-ion sieve composite material is composed of irregularly shaped spherical particles stacked and connected together, with numerous voids within the framework, thus effectively preserving the adsorption sites of the lithium-ion sieve.

[0067] Example 2:

[0068] The silica lithium-ion sieve composite materials prepared in Examples 1 to 5 were added to salt lake brine for lithium-ion adsorption. The mass of the composite material added was 1g. The adsorption was carried out at room temperature with shaking at 100rpm for 24h. The adsorption capacity was calculated (based on the lithium-ion sieve content of the composite material). The results are shown in the table below.

[0069]

[0070] Example of effect 3:

[0071] The silica lithium ion sieve composite materials of Examples 1-5 were put into seawater for lithium ion adsorption. The mass of the composite material was 0.2g and the volume of seawater was 20L. The adsorption was carried out at room temperature with shaking at 100rpm for 24h. The adsorption capacity was calculated (based on the lithium ion sieve content of the composite material). The results are shown in the table below.

[0072]

[0073] As can be seen from the above examples, the silica-lithium ion sieve composite material prepared in this application has a high adsorption capacity, reaching a maximum adsorption capacity of 29.75 mg / g in salt lake brine and a maximum adsorption capacity of 10.43 mg / g in seawater. This is mainly because this application forms a composite material with a honeycomb-like skeleton structure by mixing and extruding a porous gel with a lithium ion sieve, resulting in a high adsorption capacity. The skeleton contains a large number of pores, which greatly preserves the adsorption sites of the lithium ion sieve.

[0074] The foregoing description of this disclosure is provided to enable any person skilled in the art to implement or use this disclosure. Various modifications to this disclosure will be apparent to those skilled in the art, and the general principles applicable herein can be applied to other variations without departing from the scope of this disclosure. Therefore, this disclosure is not limited to the examples and designs described herein, but is consistent with the widest scope of the principles and novel features disclosed herein.

Claims

1. A method for preparing a silica-lithium ion sieve composite material, characterized in that, include: Polyethylene glycol and concentrated nitric acid were mixed to obtain mixture A; Under ice-water bath conditions, tetraethyl orthosilicate was added to the mixture A and stirred continuously to obtain mixture B; Mixture B was heated under sealed conditions to obtain a gel; The gel was mixed with a lithium-ion sieve, then extruded and granulated, and subsequently dried and calcined to obtain a silica-lithium-ion sieve composite material.

2. The preparation method according to claim 1, characterized in that, The mass concentration of polyethylene glycol in the mixture A is 0.05-0.06 g / mL, and the volume ratio of concentrated nitric acid to the mixture A is (0.05-0.06):

1.

3. The preparation method according to claim 1, characterized in that, The polyethylene glycol has a molecular weight of 11,000 to 3,000,000.

4. The preparation method according to claim 1, characterized in that, The mass concentration of tetraethyl orthosilicate in the mixture B is 1.2–1.3 g / mL.

5. The preparation method according to claim 1, characterized in that, The step of heating the mixture B in a sealed state to obtain a gel specifically involves heating at 60°C for 2 hours.

6. The preparation method according to claim 1, characterized in that, In the step of mixing the gel with the lithium ion sieve, the mass ratio of the gel to the lithium ion sieve is (0.5-20):

1.

7. The preparation method according to claim 1, characterized in that, In the step of mixing the gel with a lithium-ion sieve, then extruding and granulating it, and then drying and calcining it in sequence to obtain a silica-lithium-ion sieve composite material, the calcination temperature is 500-700℃.

8. The preparation method according to claim 1, characterized in that, The lithium ion sieve is H. 1.33 Mn 1.67 O4, H 1.6 Mn 1.6 O4, H2TiO3, H4Ti5O 12 One or more combinations of λ-MnO2.

9. A silica lithium ion sieve composite material prepared by any one of the preparation methods described in claims 1 to 8.

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