Preparation method of lithium-enriched material precursor

Abstract

The invention belongs to the field of inorganic enrichment materials, and discloses a preparation method of a lithium enrichment material precursor, which comprises the following steps: mixing a lithium-containing solution with an AlCl3 solution, adding an alkaline reagent for reaction to generate a chloride of lithium-aluminum double hydroxide, cleaning the chloride of lithium-aluminum double hydroxide, and carrying out preliminary crushing to obtain a lithium-aluminum double hydroxide precursor; and carrying out ball milling on the crushed product to obtain precursor powder, carrying out heat treatment on the precursor powder, adding a naphthalimide solution, and removing the solvent to obtain the lithium-enriched material precursor. According to the preparation method of the lithium-enriched material precursor, the precursor with better adhesion with the resin matrix can be manufactured, so that the adsorbability and the mechanical property of the final product lithium-enriched material are integrally improved.

Description

Technical Field

[0001] The invention belongs to the field of inorganic enrichment materials, and in particular relates to a method for preparing a lithium enrichment material precursor. Background Art

[0002] Most of my country's lithium resources come from salt lake brine, so salt lake lithium extraction technology has been widely used. At present, the main lithium extraction technology is still the adsorption method with the advantages of high selectivity and convenient recovery, and lithium-enriched materials are the key to the adsorption method. Among the many preparation methods of lithium-enriched materials, the granulation method is the most common. The lithium-enriched materials prepared by the granulation method have a high specific surface area, good mechanical stability and water permeability, can adapt to industrial column operation, and have good application prospects. The granulation process is generally direct bonding molding, that is, the precursor and the binder (generally a polymer) are directly mixed, and the granular lithium-enriched material is fixed during the polymer molding process, and then pores are formed under the action of the porogen, so that the lithium-containing solution can contact the lithium-enriched material as much as possible, thereby achieving the expected adsorption effect; another way is through polymerization reaction molding, that is, the lithium-enriched material powder is mixed with an organic monomer that can undergo polymerization reaction, and then the polymerization and cross-linking of the organic monomer are used to prepare microspheres of different particle sizes. However, in actual production, the precursor and the binder are difficult to be completely mixed and formed due to the influence of molecular polarity, which has a great impact on the adsorption and dissolution properties of the final product, the lithium-enriched material. Summary of the invention

[0003] The object of the present invention is to overcome at least one disadvantage of the prior art and provide a method for preparing a lithium-enriched material precursor.

[0004] The technical solution adopted by the present invention is:

[0005] A method for preparing a lithium-enriched material precursor comprises the following steps:

[0006] S1 uses a lithium-containing solution mixed with an AlCl3 solution, and adds an alkaline reagent to react to generate a chloride of lithium aluminum double hydroxide (LiCl·3Al(OH)3·nH2O);

[0007] S2: washing the chloride of the lithium aluminum double hydroxide and then preliminarily crushing it;

[0008] S3 ball-mills the crushed product to obtain a precursor powder;

[0009] S4: heat-treating the precursor powder, adding naphthalene diimide solution, and removing the solvent to obtain the lithium-enriched material precursor.

[0010] In the embodiment of the present application, the roughness of the surface of the precursor powder is first increased by ball milling process, and grooves are created on its surface to play a mechanical locking role, which is beneficial to the bonding of the resin matrix. The embodiment of the present application also heat treats the precursor powder to improve its mechanical properties and enhance the dissolution rate of its final product, the lithium-enriched material. At the same time, the embodiment of the present application adds a naphthalene diimide solution in the heat treatment process. In the heat treatment stage, the naphthalene diimide can construct a multi-scale strengthening interface phase on the surface of the precursor after solvent evaporation and heterogeneous nucleation, increase its surface crack extension, and reduce stress concentration, effectively improving the adhesion between the precursor powder and the resin matrix.

[0011] In some feasible implementations, the naphthalene diimide in step S4 is capped with an amino group. The naphthalene diimide capped with an amino group has a more stable state and is more conducive to constructing a multi-scale strengthening interface phase on the surface of the precursor.

[0012] In some feasible embodiments, multi-walled carbon nanotubes are also added while adding the naphthalene diimide solution in step S4. The embodiment of the present application introduces multi-walled carbon nanotubes, and under the confinement effect of the multi-walled carbon nanotubes and the dual nucleation effect with the powder surface, the naphthalene diimide undergoes an inclined self-assembly structure, so that the stress concentration point is transferred from the fiber surface to the end of the modulus platform, thereby expanding the crack and making the powder surface have a higher interfacial shear strength. At the same time, the amino-terminated naphthalene diimide can participate in the cross-linking and curing of the epoxy resin matrix, further enhancing the bonding strength between the precursor powder and the resin matrix.

[0013] In some feasible embodiments, the method of removing the solvent in step S4 is heating evaporation.

[0014] In some feasible implementations, the heating evaporation temperature is 85-110°C.

[0015] In some feasible implementations, n in the LiCl·3Al(OH)3·nH2O satisfies: 8≤n≤10.

[0016] In some feasible implementations, the ball milling process in step S3 is: adding alumina balls or steel balls to the crushed product and ball milling for 3-5 hours.

[0017] In some feasible implementations, the ball milling in step S3 is completed and then passed through a 50-mesh sieve. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0019] Figure 1 This is a process flow chart for preparing a lithium-rich material precursor according to an optional embodiment of the present application. DETAILED DESCRIPTION

[0020] Embodiments of the present embodiment are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present embodiment, and should not be construed as limiting the present embodiment.

[0021] In the description of this embodiment, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this embodiment and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on this embodiment.

[0022] In the description of this embodiment, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0023] In the description of this embodiment, it should be noted that all ranges disclosed in this application will be understood to include any and all sub-ranges included therein. For example, the stated range "3% to 20%" should be deemed to include any and all sub-ranges that start with a minimum value of 3% or greater and end with a maximum value of 20% or less, for example, 4% to 19%, or 4.5% to 15%, or 12% to 13%. At the same time, all ranges disclosed in this application are also deemed to include the endpoints of the ranges, unless otherwise explicitly stated. For example, the range "between 4 and 6" or "4 to 6" or "4-6" should generally be deemed to include the endpoints 4 and 6.

[0024] In the description of this embodiment, unless otherwise clearly defined, the terms such as setting, installing, connecting, etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in this embodiment in combination with the specific content of the technical solution. The technical solution of the present invention is further described below in combination with exemplary embodiments.

[0025] One of the main sources of lithium resources in my country is salt lake brine, so salt lake lithium extraction technology has been widely used. At present, the adsorption method has become the main lithium extraction technology due to its high selectivity and easy recovery, and lithium-enriched materials are the core technical elements of the adsorption method. Among the various methods for preparing lithium-enriched materials, the granulation method occupies a dominant position. The lithium-enriched materials obtained by the granulation method have the characteristics of large specific surface area, good mechanical stability, and good water permeability. They are very suitable for industrial column operations and show broad application potential. The process flow of the granulation method is mainly direct bonding molding. The specific steps include mixing the lithium-enriched material powder with an organic monomer that can undergo a polymerization reaction, and then using the polymerization and cross-linking of the organic monomer to prepare microspheres of different particle sizes. However, in the actual production process, due to factors such as the molecular polarity of the precursor and the binder, it is often difficult to completely mix and form. This problem has a significant impact on the adsorption and dissolution properties of the final lithium-enriched material.

[0026] In order to solve the above problems, the present embodiment provides a method for preparing a lithium-rich material precursor, comprising the following steps:

[0027] First, by Figure 1 It can be seen that lithium hydroxide is used as the lithium salt raw material, aluminum chloride is used as the non-lithium metal salt, and sodium hydroxide is used as the alkali metal hydroxide. Therefore, in the synthesis reactor, sodium hydroxide is added as an alkaline reagent to the aluminum chloride solution containing lithium ions to form aluminum lithium double hydroxide. At the same time, aluminum lithium double hydroxide is also used as a lithium enrichment material, and the reaction formula is: LiOH+3AlCl3+9NaOH+nH2O=LiCl·3Al(OH)3·nH2O+9NaCl, where 8≤n≤10; after the reaction is completed, a slurry containing LiCl·3Al(OH)3·nH2O precipitate is formed, wherein n satisfies: 8≤n≤10, and the alkaline reagent can be sodium hydroxide, potassium hydroxide or ammonia water, etc., and the solution pH is adjusted to 6-7 by adding an alkaline solvent.

[0028] After washing, the solid LiCl·3Al(OH)3·nH2O precipitate is dried by constant temperature evaporation to form a solid, which is then preliminarily crushed. It is understood that the preliminarily crushed solid precipitate can be crushed to an appropriate size by extrusion crushing, splitting crushing, impact crushing, etc., so that the subsequent grinding step can be performed. After the preliminarily crushed, the fragments are placed in a ball mill, and then a ball milling aid such as alumina balls or steel balls is added, and the ball milling is performed for 3-5 hours. In one embodiment, a liquid ball milling aid such as nano-silica, polyvinyl alcohol, silicone, triethanolamine, ethylene glycol, propylene glycol, polyacrylate, polycarboxylate, etc. is added to the ball mill, and wet ball milling is performed. After ball milling for 2-4 hours, it is dried to obtain a precursor powder. In one embodiment, the particle size of the ball milling aid is much smaller than the size of the fragments. For example, the precipitate is fixed and crushed to 40-60 mm by preliminary crushing, and a ball milling aid such as alumina balls or steel balls with a diameter of 5-15 mm is added thereto for ball milling, thereby obtaining a precursor powder with a rougher surface. In one embodiment, the precursor powder is placed in a 50-mesh sieve and shaken to obtain a precursor powder with uniform particle size.

[0029] The precursor powder is placed in a heat treatment device, such as a heating furnace. In one embodiment, the precursor powder is treated in three stages by a gradient heating method: low temperature treatment stage: heating to 60-80°C at a rate of 5-10°C / min, preferably 80°C in some embodiments, and keeping warm for 1-2h; medium temperature activation stage: heating to 100-110°C at a rate of 3-5°C / min, and keeping the temperature constant for 0.5-1h to promote the formation of a porous structure; slow cooling and stabilization stage: turn off the heating system and cool slowly with the furnace, preferably, the cooling rate is ≤2°C / min, take it out below 60°C and then cool it to avoid structural defects caused by sudden temperature changes. In one embodiment, during the heat treatment process, a specific atmosphere is used to prevent oxidation of the powder surface or other adverse reactions. Preferably, the selected specific atmosphere can be nitrogen or hydrogen. In some embodiments, the purity of the specific atmosphere is ≥99.99%. In one embodiment, naphthalene diimide and / or multi-walled carbon nanotubes can be added simultaneously in each stage of heat treatment, so as to improve the surface performance of powder, improve the hardness and wear resistance of powder, increase the crack propagation of powder surface, and improve the bonding degree of powder and high polymer such as resin during cross-linking and curing. In one embodiment, the method of adding naphthalene diimide and / or multi-walled carbon nanotubes can be thermal spraying, and the above solution is sprayed onto the surface of powder in heat treatment, so as to be able to cover the surface of powder more evenly. It is understandable that naphthalene diimide and / or multi-walled carbon nanotubes can be added during the heating stage, can also be added in the heat preservation stage, can also be added during the tempering stage, and it is understandable that naphthalene diimide and / or multi-walled carbon nanotubes can be added to different heat treatment stages respectively, can also be added to the same heat treatment stage at the same time, preferably, naphthalene diimide is added in the heat preservation stage, and multi-walled carbon nanotubes are added in the heating stage, and more preferably, the added naphthalene diimide is terminated with amino group.

[0030] After the heat treatment process is completed, the precursor is dried. In one embodiment, it can be dried at a constant temperature of 85 to 110° C., preferably, it can be dried at a constant temperature of 95° C., until the solvent on the surface of the precursor powder is removed to obtain the lithium-enriched material precursor.

[0031] The present application is further explained below in conjunction with embodiments.

[0032] Example 1

[0033] Embodiment 1 of the present application provides a method for preparing a lithium-enriched material, comprising the following steps:

[0034] Precursor preparation: In 5L of aluminum chloride solution, the concentration of aluminum chloride is 26.67g / L, add 2.8L of LiOH solution (8.5g / L), the atomic ratio of Al and Li is Al:Li=1:1, then add NaOH solution until the pH reaches 7, and stir the mixture after the reaction for 30 minutes at room temperature. Then filter out the precipitate with a filter, wash and dry it to obtain LiCl·3Al(OH)3·nH2O active ingredient material.

[0035] The active substances are impact-crushed into particles, and the particles are placed in a ball mill. Ball milling aids such as alumina balls or steel balls are added, and the ball milling is performed for 3 hours. The ball-milled precursor powder is placed in a 50-mesh sieve and shaken to obtain a precursor powder with uniform particle size.

[0036] The precursor powder was heat treated in three stages by gradient heating: low temperature treatment stage: heating to 70°C at a rate of 8°C / min and keeping warm for 1.5h; medium temperature activation stage: heating to 105°C at a rate of 4°C / min, spraying naphthalene diimide onto the powder surface by thermal spraying, and keeping the constant temperature for 0.8h; slow cooling stabilization stage: turning off the heating system and cooling slowly with the furnace at a cooling rate of 1.5°C / min, taking out to below 60°C and cooling again to avoid structural defects caused by sudden temperature changes.

[0037] The precursor powder is dried at a constant temperature of 95°C until the solvent on the surface of the precursor powder is removed to obtain the lithium-enriched material precursor. Preparation of lithium-enriched material: 800g of precursor, 80g of polyester polyurethane and polyetheramine solution are added to a closed stirrer and stirred until a paste is formed. The slurry is put into an extruder, and then the obtained thin strip material is cut into particles with a length of 2mm, and the lithium-enriched material is obtained after drying.

[0038] Example 2

[0039] Embodiment 2 of the present application provides a method for preparing a lithium-enriched material, comprising the following steps:

[0040] Precursor preparation: In 5L of aluminum chloride solution, the concentration of aluminum chloride is 26.67g / L, add 2.8L of LiOH solution (8.5g / L), the atomic ratio of Al and Li is Al:Li=1:1, then add NaOH solution until the pH reaches 7, and stir the mixture after the reaction for 30 minutes at room temperature. Then filter out the precipitate with a filter, wash and dry it to obtain LiCl·3Al(OH)3·nH2O active ingredient material.

[0041] The active substances are impact-crushed into particles, and the particles are placed in a ball mill. Ball milling aids such as alumina balls or steel balls are added, and the ball milling is performed for 3 hours. The ball-milled precursor powder is placed in a 50-mesh sieve and shaken to obtain a precursor powder with uniform particle size.

[0042] The precursor powder was heat treated in three stages by gradient heating: low temperature treatment stage: heating to 70°C at a rate of 8°C / min, spraying multi-walled carbon nanotubes onto the powder surface by thermal spraying, and keeping warm for 1.5 hours; medium temperature activation stage: heating to 105°C at a rate of 4°C / min, keeping constant temperature for 0.8 hours, at this stage, amino-terminated naphthalene diimide was sprayed onto the powder surface by thermal spraying; slow cooling stabilization stage: turning off the heating system and slowly cooling with the furnace at a cooling rate of 2°C / min, taking out to below 60°C and cooling again to avoid structural defects caused by sudden temperature changes.

[0043] The powder is dried at a constant temperature of 95° C. until the solvent on the surface of the precursor powder is removed to obtain the lithium-enriched material precursor.

[0044] Preparation of lithium-enriched material: 800 g of precursor, 80 g of polyester polyurethane and polyetheramine solution were added to a closed stirrer and stirred until a paste-like state was formed. The slurry was put into an extruder, and then the obtained thin strip material was cut into particles with a length of 2 mm, and the lithium-enriched material was obtained after drying.

[0045] Example 3

[0046] Example 3 of the present application provides a method for preparing a lithium-enriched material, which is different from Example 2 in that the naphthalene diimide spraying in the heat treatment stage in Example 3 is not capped with amino groups.

[0047] Example 4

[0048] Example 4 of the present application provides a method for preparing a lithium-enriched material, which is different from Example 2 in that Example 4 performs constant temperature drying at 85° C. after heat treatment.

[0049] Example 5

[0050] Example 5 of the present application provides a method for preparing a lithium-enriched material, which is different from Example 2 in that Example 5 performs constant temperature drying at 110° C. after heat treatment.

[0051] Example 6

[0052] Example 6 of the present application provides a method for preparing a lithium-enriched material, which is different from Example 2 in that, in the heat treatment stage of Example 6, the low-temperature treatment stage: the temperature is raised to 60°C at a rate of 5°C / min. During this stage, multi-walled carbon nanotubes are sprayed onto the surface of the powder by thermal spraying and kept warm for 1 hour; the medium-temperature activation stage: the temperature is raised to 100°C at a rate of 3°C / min and the temperature is maintained for 0.5 hours. During this stage, amino-terminated naphthalene diimide is sprayed onto the surface of the powder by thermal spraying; the slow cooling and stabilization stage: the heating system is turned off and the powder is slowly cooled with the furnace at a cooling rate of 1°C / min. The powder is taken out to below 60°C and then cooled to avoid structural defects caused by sudden temperature changes.

[0053] Example 7

[0054] Example 7 of the present application provides a method for preparing a lithium-enriched material, which is different from Example 2 in that, in the heat treatment stage of Example 7, the low-temperature treatment stage: the temperature is raised to 80°C at a rate of 10°C / min. During this stage, multi-walled carbon nanotubes are sprayed onto the surface of the powder by thermal spraying and kept warm for 2 hours; the medium-temperature activation stage: the temperature is raised to 110°C at a rate of 5°C / min and kept at a constant temperature for 1 hour. During this stage, amino-terminated naphthalene diimide is sprayed onto the surface of the powder by thermal spraying; the slow cooling and stabilization stage: the heating system is turned off and the powder is slowly cooled with the furnace at a cooling rate of 0.5°C / min. The powder is taken out to below 60°C and then cooled to avoid structural defects caused by sudden temperature changes.

[0055] Example 8

[0056] Example 8 of the present application provides a method for preparing a lithium-enriched material, which is different from Example 2 in that the multi-walled carbon nanotubes of Example 8 are sprayed simultaneously with naphthalene diimide capped with amino groups during the heat preservation stage.

[0057] Example 9

[0058] Example 9 of the present application provides a method for preparing a lithium-enriched material, which is different from Example 2 in that the multi-walled carbon nanotubes of Example 9 are sprayed during the heat preservation stage, while the amino-terminated naphthalene diimide is sprayed during the heating stage.

[0059] Example 10

[0060] Example 10 of the present application provides a method for preparing a lithium-enriched material, which is different from Example 2 in that the multi-walled carbon nanotubes of Example 10 are sprayed during the heat preservation stage, while the amino-terminated naphthalene diimide is sprayed during the heating stage.

[0061] Embodiment 11

[0062] Example 11 of the present application provides a method for preparing a lithium-enriched material, which is different from Example 2 in that the multi-walled carbon nanotubes and amino-terminated naphthalene diimide in Example 11 are sprayed simultaneously during the tempering stage.

[0063] Example 12

[0064] Example 12 of the present application provides a method for preparing a lithium-enriched material, which is different from Example 2 in that the multi-walled carbon nanotubes of Example 12 are sprayed during the tempering stage, and the amino-terminated naphthalene diimide is sprayed during the insulation stage.

[0065] Example 13

[0066] Example 13 of the present application provides a method for preparing a lithium-enriched material, which is different from Example 2 in that the multi-walled carbon nanotubes of Example 13 are sprayed during the heat preservation stage, and the amino-terminated naphthalene diimide is sprayed during the tempering stage.

[0067] Embodiment 14

[0068] Example 14 of the present application provides a method for preparing a lithium-enriched material, which is different from Example 2 in that the multi-walled carbon nanotubes of Example 14 are sprayed during the heating stage, and the amino-terminated naphthalene diimide is sprayed during the tempering stage.

[0069] Embodiment 15

[0070] Example 15 of the present application provides a method for preparing a lithium-enriched material. The difference from Example 2 is that the multi-walled carbon nanotubes of Example 15 are sprayed during the tempering stage, and the amino-terminated naphthalene diimide is sprayed during the heating stage.

[0071] Comparative Example 1

[0072] Comparative Example 1 of the present application provides a method for preparing a lithium-enriched material, comprising the following steps:

[0073] Precursor preparation: In 5L of aluminum chloride solution, the concentration of aluminum chloride is 26.67g / L, add 2.8L of LiOH solution (8.5g / L), the atomic ratio of Al and Li is Al:Li=1:1, then add NaOH solution until the pH reaches 7, and stir the mixture after the reaction for 30 minutes at room temperature. Then filter out the precipitate with a filter, wash and dry it to obtain LiCl·3Al(OH)3·nH2O active ingredient material.

[0074] The active substances are impact-crushed into particles, and the particles are placed in a ball mill. Ball milling aids such as alumina balls or steel balls are added, and the ball milling is performed for 3 hours. The ball-milled precursor powder is placed in a 50-mesh sieve and shaken to obtain a precursor powder with uniform particle size.

[0075] Preparation of lithium-enriched material: 800 g of precursor, 120 g of polyester polyurethane and polyetheramine solution were added to a closed mixer and stirred until a paste-like state was formed. The slurry was put into an extruder, and then the obtained thin strip material was cut into particles with a length of 2 mm, and the lithium-enriched material was obtained after drying.

[0076] The adsorption performance and dissolution rate of the lithium-enriched materials obtained in the above examples and comparative examples were tested, and the results are shown in Table 1 below:

[0077] Table 1

[0078] Example Adsorption amount / (mg / g) Dissolution rate / % Example 1 5.76 0.072 Example 2 6.65 0.051 Example 3 6.18 0.062 Example 4 6.62 0.054 Example 5 6.63 0.054 Example 6 6.54 0.058 Example 7 6.55 0.059 Example 8 6.60 0.054 Example 9 6.59 0.056 Example 10 6.36 0.059 Embodiment 11 6.51 0.061 Example 12 6.55 0.058 Example 13 6.52 0.059 Embodiment 14 6.55 0.058 Embodiment 15 6.49 0.062 Comparative Example 1 4.75 0.261

[0079] Detection Methods

[0080] Adsorption amount detection method:

[0081] 3kg of lithium-enriched material was put into a reaction tube with a diameter of 10cm, and salt lake brine passed through the tower at a rate of 8 cubic decimeters per hour. After 4 hours of treatment, a lithium-enriched material with stable adsorption was obtained. Subsequently, the lithium-enriched material with stable adsorption was desorbed with distilled water, and lithium was collected by filtering to remove impurities and the weight was calculated, which was the adsorption amount (mg / g).

[0082] Dissolution rate detection method:

[0083] The above adsorption experiment was repeated 5 times, and the weight of the lithium-enriched material was finally measured and divided by the initial 3 kg to obtain the dissolution rate.

[0084] By comparing Example 1 and Comparative Example 1 (prior art), it can be seen that Example 1 of the present application enhances the adhesion between the precursor and the organic monomer capable of polymerization reaction by adding a process of heat treatment of the precursor powder and adding naphthalene diimide to spray the powder surface during the heat treatment stage, thereby greatly improving the adsorption performance and dissolution rate of the lithium-enriched material.

[0085] By comparing Example 1, Example 2 and Example 3, it can be seen that Example 2 of the present application uses multi-walled carbon nanoparticles and uses amino-terminated naphthalene diimide to spray the powder in the heat treatment process, which effectively improves the adhesion between the precursor and the organic monomer that can undergo polymerization reaction, thereby improving the adsorption performance and dissolution rate of the lithium-enriched material.

[0086] By comparing Example 2 and Examples 6-15, it can be seen that the addition of multi-walled carbon nanotubes and naphthalene diimide capped with amino groups in different heat treatment stages has a certain influence on the final adhesion between the precursor powder and the organic monomer that can undergo polymerization reaction. At the same time, it can be seen from Table 1 that Example 2 of the present application adds multi-walled carbon nanotubes in the heating stage and adds naphthalene diimide capped with amino groups in the insulation stage, which can enable the lithium-enriched material to obtain more excellent adsorption performance and dissolution rate.

[0087] The above is a further detailed description of the present invention, which should not be regarded as a limitation on the specific implementation of the present invention. For ordinary technicians in the technical field to which the present invention belongs, simple deduction or replacement without departing from the concept of the present invention is within the protection scope of the present invention.

Claims

1. A method for preparing a lithium-enriched material precursor, characterized in that: The following steps are involved: S1 uses a lithium-containing solution mixed with an AlCl3 solution, and adds an alkaline reagent to react to generate a chloride of lithium aluminum double hydroxide (LiCl·3Al(OH)3·nH2O); S2: washing the chloride of the lithium aluminum double hydroxide and then preliminarily crushing it; S3 ball-mills the crushed product to obtain a precursor powder; S4: heat-treating the precursor powder, adding naphthalene diimide solution, and removing the solvent to obtain the lithium-enriched material precursor.

2. The method for preparing a lithium-rich material precursor according to claim 1, characterized in that: The naphthalene diimide in step S4 is capped with an amino group.

3. The method for preparing a lithium-rich material precursor according to claim 1, characterized in that: In the step S4, multi-walled carbon nanotubes are added at the same time as the naphthalene diimide solution is added.

4. The method for preparing a lithium-rich material precursor according to claim 1, characterized in that: The method of removing the solvent in step S4 is heating evaporation.

5. The method for preparing a lithium-rich material precursor according to claim 4, characterized in that: The heating evaporation temperature is 85-110°C.

6. The method for preparing a lithium-rich material precursor according to claim 1, characterized in that: The n in the LiCl·3Al(OH)3·nH2O satisfies: 8≤n≤10.

7. The method for preparing a lithium-rich material precursor according to claim 1, characterized in that: The ball milling process in step S3 is: adding alumina balls or steel balls to the crushed product and ball milling for 3-5 hours.

8. The method for preparing a lithium-rich material precursor according to claim 1, characterized in that: After the ball milling is completed in step S3, the product is sieved with a 50-mesh screen.

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