Lithium extraction adsorption composite material and preparation method thereof

Abstract

The application discloses a lithium extraction adsorption composite material and a preparation method thereof in the technical field of lithium extraction adsorption materials, and aims to solve the problems of the existing technology, such as the powder shape of the adsorbent used for water system lithium extraction, the difficulty in transportation and storage, the poor fluidity and permeability, the high powder loss rate, the difficulty in powder recovery and the like, and the lithium extraction adsorption composite material comprises the following steps: stirring and dispersing polyurethane prepolymer in deionized water to form an emulsion, and placing the emulsion at a constant temperature a; after adding lithium extraction adsorbent powder into the emulsion, stirring and dispersing, continuously stirring at a temperature b, and uniformly stirring and adding a catalyst, a pore forming agent and an initiator in sequence; transferring the lithium gel material to a mold, and placing the lithium gel material in a pelletizer after gel polymerization and molding to carry out pelletizing and the like. The lithium extraction adsorption composite material prepared by the application has good mechanical strength and stability, fast adsorption rate, convenient desorption and the like, the use of organic solvents is avoided, the preparation cost of the adsorbent is reduced, and the biological environment is friendly.

Description

Technical Field

[0001] This invention relates to a lithium extraction adsorption composite material and its preparation method, belonging to the technical field of lithium extraction adsorption materials. Background Technology

[0002] Lithium resources are considered a key element of the modern energy revolution. In the past decade, the demand for lithium products has surged like never before, mainly due to the rapid increase in lithium consumption in applications such as portable electronics, new energy vehicles, and large-scale grid storage.

[0003] Currently, spodumene and salt lakes remain the main sources of increased capacity, accounting for 92% of total capacity. The contribution of salt lakes to incremental capacity increased significantly in 2023 compared to 2022, with the proportion of new capacity rising from 30.2% to 44%. Therefore, lithium extraction from water systems is becoming increasingly important.

[0004] For water systems such as salt lakes and gas field water, adsorption is one of the effective methods for lithium extraction. Currently, adsorbents that can be used for lithium extraction from water systems include manganese-based ion sieves, titanium-based ion sieves, and lithium-aluminum layered adsorbents. However, the adsorbents currently developed are generally in powder form. In practical industrial applications, powder transportation and storage are difficult, and the poor flowability and permeability can easily lead to difficulties in filling, high bed resistance, high powder loss rate, and difficulty in powder recovery.

[0005] Therefore, powders need to be shaped, and the main shaping methods include bonding molding, film-forming molding, and polymerization molding. Bonding molding often uses organic materials as binders and employs phase inversion processes for shaping. However, organic binders have poor hydrophilicity, which reduces the lithium exchange rate of the formed adsorbent and generally lowers the adsorption capacity. Film-forming molding involves adding the adsorbent powder to a casting solution and then forming a film. Because polymers can mask some active sites in the adsorbent powder, the adsorption capacity is also reduced after shaping. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a lithium extraction adsorption composite material and its preparation method. The prepared lithium extraction adsorption composite material has good mechanical strength and stability, fast adsorption rate and convenient desorption, and avoids the use of organic solvents, reducing the cost of adsorbent preparation and being environmentally friendly.

[0007] To achieve the above objectives, the present invention is implemented using the following technical solution:

[0008] On the one hand, the present invention provides a method for preparing a lithium extraction adsorption composite material, comprising the following steps:

[0009] The polyurethane prepolymer was stirred and dispersed in deionized water to form an emulsion, which was then kept at a constant temperature a.

[0010] After adding lithium-extracting adsorbent powder to the emulsion and stirring to disperse it, the catalyst, pore-forming agent and initiator were added sequentially while stirring at temperature b. After stirring evenly, lithium gel material was obtained.

[0011] The lithium gel material was transferred into a mold, allowed to stand and polymerize, and then placed into a pelletizer for pelletizing and washing to obtain lithium-extracting adsorption composite material particles.

[0012] The lithium-adsorption composite material particles were stored by immersing them in a lithium-containing solution.

[0013] Furthermore, the polyurethane prepolymer is an alicyclic isocyanate, with its hard segment being isophorone diisocyanate and its soft segment being polyether polyol, and hydroxyethyl methyl styrene as an active group grafted onto the end of the polyurethane.

[0014] Furthermore, the preparation of the polyurethane prepolymer includes:

[0015] A mixed solution was obtained by stirring 1-1.5 parts of polyether polyol, 1.5-3 parts of isophorone diisocyanate and 1.5-3 parts of hydroxyethyl methyl styrene under nitrogen protection.

[0016] Add 0.01~0.05 parts of catalyst and 0.01~0.1 parts of polymerization inhibitor to the mixed solution, and carry out the prepolymerization reaction at 60~75℃ for 4~5 hours.

[0017] Furthermore, the catalyst is dibutyltin dilaurate and / or stannous octoate, and the polymerization inhibitor is one or more of hydroquinone, methoxyphenol, p-tert-butylcatechol, and p-benzoquinone.

[0018] Furthermore, the total mass percentages of the polyurethane prepolymer, deionized water, lithium-extracting adsorbent powder, catalyst, pore-forming agent, and initiator are respectively (8%~15%): (15%~60%): (30%~75%): (0.1%~3%): (1%~5%): (0.1%~3%).

[0019] Furthermore, the temperature a is 0~20℃, and the placement time is not less than 10 minutes.

[0020] Furthermore, the average particle size of the lithium-extracting adsorbent powder does not exceed 300 micrometers, and it includes one or more of manganese-based adsorbents, titanium-based adsorbents, and aluminum-based adsorbents.

[0021] Furthermore, the catalyst is tetramethylethylenediamine, the pore-forming agent is one or more of sodium chloride, potassium chloride, sodium carbonate, sodium sulfate, potassium sulfate, potassium carbonate, sodium nitrate, and potassium nitrate, and the initiator is ammonium persulfate and / or potassium persulfate.

[0022] Furthermore, the temperature b is 25~35℃.

[0023] On the other hand, the present invention also provides a lithium extraction adsorption composite material, which is prepared by the preparation method of the lithium extraction adsorption composite material described in any one of the above claims.

[0024] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0025] The lithium extraction adsorption composite material prepared by this invention uses polyurethane as a skeleton, which has good mechanical strength and stability, fast adsorption rate and large adsorption capacity, is not easy to shed powder, is easy to separate and recycle, and can be used repeatedly and continuously.

[0026] The method for preparing lithium adsorption composite materials according to the present invention does not require the addition of a large amount of organic solvent, which reduces costs and is environmentally friendly, making it suitable for large-scale production. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the lithium extraction adsorption composite material prepared in Example 1 of the present invention;

[0028] Figure 2 This is a schematic diagram of the adsorption capacity of the lithium extraction adsorption composite material prepared in Example 2 of the present invention for 30 cycles of adsorption of gas field water.

[0029] Figure 3 This is a schematic diagram showing the change in the adsorption capacity of the molded aluminum particles adsorbing gas field water over time in Embodiment 2 and Comparative Example 1 of the present invention. Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0031] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and should be understood to include values ​​close to those ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0032] For the purposes of this specification and the appended claims, unless otherwise stated, all expressions, percentages, or proportions, and other numerical values ​​used in this specification and the appended claims, are to be understood to be modified by the term "about" in all cases. Furthermore, all scopes disclosed herein include their endpoints and can be combined independently. Example

[0033] Take 3g of polyurethane prepolymer and disperse it in 15mL of deionized water with high-speed stirring to form a stable emulsion. Place it at 4℃ for 30 min.

[0034] 30 g of LiMn2O4 adsorbent powder (passed through a 200-mesh sieve) was added and dispersed by high-speed stirring. Then, 0.25 g of tetramethylethylenediamine, 1.5 g of sodium chloride, and 0.25 g of potassium persulfate were added at 30°C and stirred rapidly until homogeneous to obtain the lithium gel material.

[0035] The lithium gel material was transferred to a special mold and allowed to stand for 10 minutes to allow the gel to polymerize and solidify. It was then placed in a pelletizer and cut into 2.5*2.5*2.5 mm cubes. After washing with deionized water, the lithium extraction and adsorption composite material (manganese-based adsorbent) was obtained. Figure 1 As shown.

[0036] The lithium adsorption composite material was soaked in deionized water to fully swell and stored at low temperature in the dark.

[0037] The formed manganese-based adsorbent was applied to the brine of Chaka Salt Lake (lithium ion concentration 287 mg / L) and the adsorption capacity was measured to be 17.75 mg / g. Example

[0038] Take 4.5g of polyurethane prepolymer and disperse it in 10mL of deionized water with high-speed stirring to form a stable emulsion. Place it at 4℃ for 30 min.

[0039] 32.5 g of LiCl•2Al(OH)3•nH2O powder (passed through a 200-mesh sieve) was added and dispersed by high-speed stirring. Then, 0.25 g of tetramethylethylenediamine, 2.25 g of sodium chloride, and 0.5 g of potassium persulfate were added at 30 °C and stirred rapidly until homogeneous to obtain the lithium gel material.

[0040] The lithium gel material was transferred into a special mold and allowed to stand for 10 minutes until the gel polymerized and formed. Then, it was placed in a pelletizer and cut into 1.5*1.5*1.5 mm cubes. The cubes were then washed with deionized water to obtain the lithium extraction adsorption composite material (aluminum-based adsorbent).

[0041] The lithium extraction adsorption composite material was immersed in deionized water until fully swollen and stored at a low temperature in the dark. After long-term immersion, the liquid remained clear, and no powder shedding was observed.

[0042] like Figure 2 As shown, the adsorption capacity of the formed aluminum-based adsorbent was measured to be 2.84 mg / g when applied to gas field water (lithium ion concentration 75 mg / L). After elution with neutral desorption solution, the adsorption capacity was still maintained at 2.77 mg / g after 30 cycles. Example

[0043] Take 3g of polyurethane prepolymer and disperse it in 20mL of deionized water with high-speed stirring to form a stable emulsion. Place it at 4℃ for 30 min.

[0044] 25 g of Li₂TiO₃ powder (passed through a 200-mesh sieve) was added and dispersed by high-speed stirring. Then, 0.25 g of tetramethylethylenediamine, 1.5 g of sodium chloride, and 0.25 g of potassium persulfate were added at 30°C and stirred rapidly until homogeneous to obtain the lithium gel material.

[0045] The lithium gel material was transferred to a special mold and allowed to stand for 10 minutes to allow the gel to polymerize and solidify. The resulting material was then placed in a pelletizer and cut into 1.5*1.5*1.5 mm cubes. After washing with deionized water, the lithium extraction and adsorption composite material (titanium-based adsorbent) was obtained.

[0046] The lithium adsorption composite material was soaked in deionized water to fully swell and stored at low temperature in the dark.

[0047] The adsorption capacity of the formed titanium-based adsorbent was measured to be 12.60 mg / g when applied to the brine of Chaka Salt Lake (lithium ion concentration 287 mg / L).

[0048] Comparative Example 1:

[0049] The lithium extraction adsorption composite material obtained by solvent reverse extrusion granulation is prepared as follows:

[0050] Under heating and stirring conditions at 70℃ and 300rpm, 15.5g of polyvinyl chloride was dissolved in 35mL of N,N-dimethylformamide, and 2mL of silane coupling agent was added. After the binder was completely dissolved, 2.25g of sodium chloride and 32.5g of LiCl•2Al(OH)3•nH2O powder (passed through a 200-mesh sieve) were mixed with the binder to form a ball, which was then placed in an extrusion molding machine with an outlet aperture of 1.5mm to obtain a strip. After curing in air for 1 hour, it was cut into 1.5mm columnar particles, cured in air for another hour, and then transferred to a vacuum drying oven at 70℃ for 4 hours to obtain the molded adsorbent material.

[0051] Based on the dry weight conversion, the same dry weight of the shaped adsorbents from Example 2 and Comparative Example 1 was weighed and added to actual gas field water (lithium ion concentration 75 mg / L). Adsorption was performed for 48 hours under shaking conditions at 30°C and 150 rpm. The adsorption capacity of each adsorbent over time is as follows: Figure 3 As shown.

[0052] Depend on Figure 3It can be seen that the adsorption capacity of both Example 2 and Comparative Example 1 gradually increases with time. The aluminum-based lithium extraction composite material obtained in Example 2 reaches adsorption equilibrium in an actual gas field water system in about 20 hours, with a final adsorption capacity of 2.84 mg / g. In contrast, the aluminum-based lithium extraction composite material obtained by solvent reverse extrusion in Comparative Example 1 requires 40 hours to reach adsorption equilibrium in a gas field water system, with a final adsorption capacity of 2.52 mg / g. It is evident that the lithium extraction adsorption composite material obtained in Example 2 has advantages in both adsorption rate and adsorption capacity.

[0053] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a lithium-uptake adsorbent composite material, characterized by, The method comprises the following steps: stirring and dispersing a polyurethane prepolymer in deionized water to form an emulsion, the polyurethane prepolymer being a cycloaliphatic isocyanate, the hard segment of which is isophorone diisocyanate, the soft segment of which is a polyether polyol, and the hydroxyethyl methacrylate being grafted to the end of the polyurethane as an active group; adding lithium extraction adsorbent powder to the emulsion and stirring and dispersing, and then adding a catalyst, a pore-forming agent and an initiator in sequence while stirring at temperature b, and then stirring uniformly to obtain a lithium gel material; transferring the lithium gel material to a mold, allowing the gel to polymerize and form, and then cutting into particles in a granulator, and then cleaning to obtain lithium extraction adsorption composite material particles; soaking the lithium extraction adsorption composite material particles in a lithium-containing solution for storage; the catalyst being tetramethyl ethylenediamine, and the pore-forming agent being one or more of sodium chloride, potassium chloride, sodium carbonate, sodium sulfate, potassium sulfate, potassium carbonate, sodium nitrate and potassium nitrate.

2. The method for preparing the lithium extraction adsorption composite material according to claim 1, characterized in that, The preparation of the polyurethane prepolymer comprises: stirring and mixing 1-1.5 parts of polyether polyol, 1.5-3 parts of isophorone diisocyanate and 1.5-3 parts of hydroxyethyl methacrylate under nitrogen protection to obtain a mixed solution; adding 0.01-0.05 parts of a catalyst and 0.01-0.1 parts of a polymerization inhibitor to the mixed solution, and then performing prepolymerization at 60-75°C, the reaction time being 4-5h, and the catalyst being dibutyltin dilaurate and / or stannous octoate.

3. The method for preparing the lithium extraction adsorption composite material according to claim 2, characterized in that, The polymerization inhibitor being one or more of hydroquinone, methoxyphenol, p-tert-butylcatechol and p-benzoquinone.

4. The method for preparing the lithium extraction adsorption composite material according to claim 1, characterized in that, The total mass proportions of the polyurethane prepolymer, deionized water, lithium extraction adsorbent powder, catalyst, pore-forming agent and initiator are (8%-15%):(15%-60%):(30%-75%):(0.1%-3%):(1%-5%):(0.1%-3%).

5. The method for preparing the lithium extraction adsorption composite material according to claim 1, characterized in that, The temperature a is 0-20°C, and the standing time is not less than 10 minutes.

6. The method of claim 1, wherein the lithium-adsorbing composite material is prepared by the steps of: mixing a lithium-adsorbing metal oxide with a carbon material; and heat-treating the mixture. The average particle size of the lithium extraction adsorbent powder is not more than 300 microns, and the lithium extraction adsorbent powder comprises one or more of a manganese-based adsorbent, a titanium-based adsorbent and an aluminum-based adsorbent.

7. The method of claim 1, wherein the lithium-adsorbing composite material is prepared by the steps of: preparing a mixture of a lithium-adsorbing metal oxide and a carbon material; and mixing the mixture with a binder. The initiator being ammonium persulfate and / or potassium persulfate.

8. The method of claim 1, wherein the lithium-adsorbing composite material is prepared by the steps of: mixing a lithium-adsorbing metal oxide with a carbon material; and heat-treating the mixture. The temperature b is 25-35°C.

9. A lithium extraction adsorbent composite, characterized in that, The lithium extraction adsorption composite material is prepared by the method of any one of claims 1-8. The lithium extraction adsorption composite material is prepared by the method of any one of claims 1-8.

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