Preparation method of porous cubic manganese-based lithium ion sieve adsorbent

Abstract

This invention discloses a method for preparing a porous cubic manganese-based lithium-ion sieve adsorbent, comprising: S10, mixing a lithium source and cubic manganese carbonate in a Li to Mn molar ratio of 0.1 to 1.6 and then grinding the mixture to obtain a mixed powder; S20, calcining the mixed powder to obtain the porous cubic manganese-based lithium-ion sieve adsorbent. In this method, a regular porous cubic manganese-based lithium-ion sieve can be obtained by mixing and grinding the manganese source and cubic manganese carbonate followed by a single calcination step. Compared to the two-step method of hydrothermal treatment and calcination in the prior art, the method provided by this invention is simpler and easier to operate, reduces the process difficulty, and allows for better control of the porous cubic morphology of the resulting ion sieve adsorbent, thus ensuring good dispersion during the adsorption process in salt lake brine and exhibiting excellent adsorption performance.

Description

Technical Field

[0001] This invention belongs to the field of ion sieve adsorption material technology, and particularly relates to a method for preparing a porous cubic manganese-based lithium ion sieve adsorbent. Background Technology

[0002] Lithium, hailed as the "white oil of the new era," is an important strategic resource widely used in new energy vehicles, electronic products, energy storage, and many other fields. Lithium-ion batteries, with their high energy density and low self-discharge characteristics, are widely used in portable electronic products and electric vehicles. Lithium also has extensive applications in lubricating greases, ceramics, glass, aerospace alloys, and the nuclear industry. Globally, lithium supply is primarily derived from spodumene extraction, with Australia being the leading supplier. South American salt lakes are also a major source of lithium, with their substantial lithium production mainly derived from the brine (lithium-rich) of the evaporation ponds in Chile's Atacama Desert. my country is a major lithium resource country, with abundant lithium resources in its salt lakes, possessing extremely high exploitation value.

[0003] Traditional lithium extraction from salt lakes typically involves first concentrating the raw brine by spreading it over a large area of ​​salt pans, then further extracting and separating lithium using methods such as membrane separation, electrodialysis, and multi-stage extraction. However, the process of evaporating and concentrating the brine by spreading it can easily result in significant lithium loss. Because the raw brine contains a variety of ions, membrane methods and extraction methods are difficult to apply. Adsorbent extraction methods exhibit high selectivity and adsorption capacity for lithium ions in solution; therefore, direct lithium extraction from salt lake brine using adsorption is highly feasible. Ion sieve adsorbents have irreplaceable advantages over other inorganic adsorbents in terms of adsorption capacity and selectivity for lithium ions. Based on their main chemical components, ion sieve adsorbents can be divided into three main categories: aluminum-based, titanium-based, and manganese-based. Compared to the former two, manganese-based adsorbents have higher selectivity and capacity, lower toxicity, lower cost, and higher chemical stability, making them a promising lithium ion sieve adsorbent for extracting lithium from salt lake brine.

[0004] Chinese patent application (publication number: CN110240202A) discloses a method for preparing a manganese-based lithium-ion sieve. First, a solid is generated from manganese dioxide and a lithium-containing solution via a hydrothermal method. Then, the solid is calcined under a non-reducing gas atmosphere to obtain the manganese-based lithium-ion sieve. The preparation process provided by this method consists of two steps: hydrothermal treatment and calcination.

[0005] Chinese patent application (publication number: CN109289758A) discloses a method for preparing a hexagonal sheet-like manganese-based lithium-ion sieve adsorbent. The method involves sequentially mixing a manganese source, a lithium source, and an organic amine compound to obtain a mixed solution. The mixed solution is then hydrothermally heated to obtain solid LiMn₂O₄. Subsequently, the solid LiMn₂O₄ is calcined to obtain Li 1.6 Mn1.6 O4 manganese-based lithium-ion sieve adsorbent. The preparation process provided by this method requires the use of organic amine compounds and is carried out in two steps: hydrothermal and calcination.

[0006] The preparation processes of the manganese-based ion sieve adsorbents disclosed in the prior art generally involve two steps: hydrothermal treatment and calcination. Both processes suffer from problems such as long hydrothermal treatment times and the need for a special atmosphere during calcination. Furthermore, in the process of preparing the intermediate from the raw material through hydrothermal treatment and then further calcining it to obtain the adsorbent, variables such as the morphology and size of the adsorbent cannot be well controlled. Inhomogeneous morphology may adversely affect the adsorption performance of the adsorbent. Summary of the Invention

[0007] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a method for preparing a porous cubic manganese-based lithium ion sieve adsorbent, so as to reduce the difficulty of the preparation process of manganese-based lithium ion sieve adsorbent.

[0008] To address the above problems, this invention provides a method for preparing a porous cubic manganese-based lithium-ion sieve adsorbent, comprising:

[0009] S10. The lithium source and cubic manganese carbonate are mixed in a ratio of Li to Mn of 0.1 to 1.6 and then ground to obtain a mixed powder.

[0010] S20. The mixed powder is calcined to obtain a porous cubic manganese-based lithium ion sieve adsorbent.

[0011] Preferably, the lithium source is selected from one or more of lithium hydroxide, lithium nitrate, lithium chloride, and lithium carbonate.

[0012] Preferably, the calcination temperature is 300℃~800℃ and the time is 60min~500min.

[0013] Preferably, the cubic manganese carbonate is prepared according to the following process, including:

[0014] S11. Potassium permanganate, sucrose and tartaric acid are added to water at the same time and stirred until the solid phase is completely dispersed to form a suspension, thus obtaining the reaction solution.

[0015] S12. Transfer the reaction solution to a reaction vessel and heat it to carry out a hydrothermal reaction.

[0016] S13. The hydrothermal reaction product is centrifuged to obtain a solid product. The solid product is then washed and dried sequentially to prepare cubic manganese carbonate particles.

[0017] Preferably, in step S11, magnetic stirring is used for stirring at a speed of 400 r / min to 600 r / min.

[0018] Preferably, the mass ratio of potassium permanganate, sucrose, tartaric acid and water in the suspension is (0.1-5):(0.1-1):(0.1-2):(60-360).

[0019] Preferably, in step S11, a pH adjusting solution is slowly added to the suspension while stirring continuously, so that the pH value of the reaction solution is 2.8 to 3.2.

[0020] Preferably, the pH adjusting solution is selected from at least one of LiOH solution, NaOH solution, KOH solution, HCl solution, H2SO4 solution, HNO3 solution and C2H4O2 solution.

[0021] Preferably, the concentration of the pH adjusting solution is 1.5 g / L to 2.5 g / L.

[0022] Preferably, in step S12, the temperature for the hydrothermal reaction is 100℃~200℃, and the reaction time is 12h~36h.

[0023] The method for preparing porous cubic manganese-based lithium-ion sieve adsorbent provided in this invention involves mixing and grinding a manganese source with cubic manganese carbonate, followed by one-step calcination to obtain a regular porous cubic manganese-based lithium-ion sieve. Compared with the two-step method of hydrothermal treatment and calcination in the prior art, the method provided by this invention is simple and easy to operate, reduces the process difficulty, and the porous cubic morphology of the obtained ion sieve adsorbent can be better controlled, thereby ensuring that it can be well dispersed in the adsorption process of salt lake brine and has a good adsorption effect. Attached Figure Description

[0024] Figure 1 This is the XRD pattern of the cubic manganese carbonate particle sample in Example 1 of the present invention;

[0025] Figure 2 This is a SEM image of the cubic manganese carbonate particle sample in Example 1 of the present invention;

[0026] Figure 3 This is the N2 adsorption-desorption curve of the cubic manganese carbonate particle sample in Example 1 of this invention;

[0027] Figure 4 This is the pore size distribution curve of the cubic manganese carbonate particle sample in Example 1 of the present invention;

[0028] Figure 5 This is a SEM image of the cubic manganese carbonate particle sample in Example 2 of the present invention;

[0029] Figure 6 This is a SEM image of the cubic manganese carbonate particle sample in Example 3 of the present invention;

[0030] Figure 7 This is a SEM image of the cubic manganese carbonate particle sample in Example 4 of the present invention;

[0031] Figure 8 This is the XRD pattern of the manganese-based lithium ion sieve adsorbent sample in Example 5 of the present invention;

[0032] Figure 9 This is a SEM image of the manganese-based lithium ion sieve adsorbent sample in Example 5 of this invention;

[0033] Figure 10 This is the XRD pattern of the manganese-based lithium ion sieve adsorbent sample in Example 6 of the present invention;

[0034] Figure 11 This is the XRD pattern of the manganese-based lithium ion sieve adsorbent sample in Example 7 of the present invention;

[0035] Figure 12 This is the XRD pattern of the manganese-based lithium ion sieve adsorbent sample in Example 8 of the present invention;

[0036] Figure 13 This is the XRD pattern of the manganese-based lithium ion sieve adsorbent sample in Example 9 of the present invention. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the present invention clearer, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Examples of these preferred embodiments are illustrated in the drawings. The embodiments of the present invention shown in and described with reference to the drawings are merely exemplary, and the present invention is not limited to these embodiments.

[0038] It should also be noted that, in order to avoid obscuring the invention with unnecessary details, only the structures and / or processing steps closely related to the solution according to the invention are shown in the accompanying drawings, while other details that are not closely related to the invention are omitted.

[0039] This invention provides a method for preparing a porous cubic manganese-based lithium-ion sieve adsorbent, the method comprising the following steps:

[0040] Step S10: The lithium source and cubic manganese carbonate are mixed and ground in a Li to Mn molar ratio of 0.1 to 1.6 to obtain a mixed powder. In step S10, the lithium source can be selected from one or more of lithium hydroxide, lithium nitrate, lithium chloride, and lithium carbonate.

[0041] Step S20: The mixed powder is calcined to obtain a porous cubic manganese-based lithium-ion sieve adsorbent. During the calcination process in step S20, if the calcination time is too short or the calcination temperature is too low, the adsorbent may not be completely converted, and the crystal structure may be unstable, leading to a decrease in its adsorption performance and cycle life. Conversely, if the calcination time is too long or the calcination temperature is too high, the adsorbent may undergo excessive sintering or decomposition, resulting in changes in the crystal structure and loss of physical properties, which also affects its adsorption performance. Therefore, to obtain optimal adsorption performance, it is necessary to control the appropriate calcination time and temperature. In step S20 of this embodiment, the preferred calcination temperature is 300℃~800℃, and the preferred time is 60min~500min.

[0042] In step S10, the morphology of the raw material, cubic manganese carbonate, has a significant impact on the morphology of the final cubic manganese-based lithium-ion sieve adsorbent. The cubic manganese carbonate used in this embodiment of the invention can be prepared according to the following process, including the following steps:

[0043] Step S11: Add potassium permanganate, sucrose and tartaric acid to water at the same time, and stir until the solid phase is completely dispersed to form a suspension to obtain the reaction solution.

[0044] Step S12: Transfer the reaction solution to a reaction vessel and heat it to carry out a hydrothermal reaction.

[0045] Step S13: Centrifuge the hydrothermal reaction product to obtain a solid product, and then wash and dry the solid product in sequence to prepare cubic manganese carbonate particles.

[0046] In the specific scheme, magnetic stirring is used in step S11, and the stirring speed can be 400 r / min to 600 r / min, preferably 500 r / min. It is worth noting that in step S11, a certain mass of potassium permanganate, sucrose, and tartaric acid are added directly to the water being magnetically stirred at once. Changing the addition method would cause the solution pH to gradually decrease with the amount of tartaric acid added, leading to uneven size of the generated cubic MnCO3 particles or the formation of large aggregates. This is one of the reasons why a relatively high stirring speed is set in this step.

[0047] Furthermore, considering the influence of the material ratio in the hydrothermal reaction solution on the morphology and structure of the target product, i.e. the nucleation rate and growth rate of the particles, the preferred mass ratio of potassium permanganate, sucrose, tartaric acid and water in the suspension is (0.1-5):(0.1-1):(0.1-2):(60-360).

[0048] As a preferred embodiment, in step S11, a pH adjusting solution is slowly added to the suspension while continuous stirring, so that the pH value of the reaction solution is 2.8–3.2, more preferably 3. The pH of the hydrothermal reaction solution is one of the important factors affecting the morphology of the product, mainly influencing the solubility, supersaturation, crystal growth rate, and crystal particle size distribution of the reactant solution. Therefore, the progress of the hydrothermal reaction and the morphology of the product can be controlled by appropriately adjusting the pH of the reaction solution.

[0049] Furthermore, after the pH of the reaction solution is stabilized, magnetic stirring is continued for a certain period of time (usually more than 30 minutes). This is mainly because the reaction of potassium permanganate with water produces gases such as oxygen. If the stirring is insufficient, the gases cannot escape completely, which may cause the reaction solution to explode in the reaction vessel, thus improving the safety of the process.

[0050] The pH adjusting solution may be selected from at least one of LiOH solution, NaOH solution, KOH solution, HCl solution, H2SO4 solution, HNO3 solution, and C2H4O2 solution. The concentration of the pH adjusting solution may be 1.5 g / L to 2.5 g / L, preferably 2 g / L.

[0051] In the specific scheme, in step S12, the temperature for the hydrothermal reaction is 100℃~200℃, and the reaction time is 12h~36h.

[0052] The effects of hydrothermal temperature on hydrothermal products are mainly manifested in altering reaction kinetics, product properties, byproduct formation, and crystal growth. For example, at lower temperatures, crystal growth is slower, resulting in smaller and less uniformly distributed grains. At higher temperatures, crystal growth is faster, leading to larger and more uniformly distributed grains. Furthermore, the inner liner of the reactor used in this method is made of polytetrafluoroethylene (PTFE), which has an upper operating temperature limit of 220°C. To ensure operational safety and the proper functioning of the hydrothermal reaction, a reaction temperature range of 100°C to 200°C is preferred.

[0053] Hydrothermal time has a significant impact on the morphology, composition, purity, and properties of hydrothermal products. If the hydrothermal time is too long, the products will gradually grow, aggregate, or form more complex structures; the purity of the hydrothermal products will increase with prolonged hydrothermal time, thus affecting their properties. To ensure the complete hydrothermal reaction and avoid unnecessary energy consumption, a hydrothermal time of 12 to 36 hours is preferred.

[0054] In the specific scheme, step S13 involves sequentially washing the solid product with deionized water and ethanol multiple times until the supernatant is neutral. Typically, this washing process needs to be repeated at least three times. This is mainly because after the hydrothermal reaction, the product surface may contain impurities such as reaction byproducts or reactants. To avoid further impact from these impurities, water and alcohol washing can be used to remove them, thereby improving the product's purity.

[0055] Example 1

[0056] (1) Weigh out 0.474 g of potassium permanganate, 0.595 g of sucrose and 0.15 g of tartaric acid and add them to 160 mL of deionized water. Set the magnetic stirring speed to 500 r / min and stir for more than 30 min until the solid reactants are completely dispersed to form a suspension, thus obtaining the reaction solution.

[0057] (2) Transfer the above reaction solution into a reaction vessel and place it in an oven for hydrothermal reaction. Set the hydrothermal reaction temperature to 160℃ and the hydrothermal time to 20h.

[0058] (3) The hydrothermal product was centrifuged to obtain a solid product. The solid product was washed three times with deionized water and ethanol until the supernatant was neutral and then dried. The resulting cubic MnCO3 particles were named Sample 1A.

[0059] In this embodiment, the obtained sample 1A was subjected to scanning electron microscopy (SEM), X-ray diffraction (XRD), and N2 adsorption-desorption tests. The test results are as follows:

[0060] Figure 1 This is the XRD pattern of sample 1A. A search revealed that sample 1A is MnCO3 (JCPDS PDF#99-0089), and the absence of other diffraction peaks in the spectrum indicates that the prepared sample 1A is high-purity MnCO3.

[0061] Figure 2 This is the SEM image of sample 1A. As can be seen from the image, this method can be used to synthesize MnCO3 particles with a particle size of approximately 1.5 μm, good dispersibility, and a regular cubic shape in one step via hydrothermal synthesis.

[0062] Figure 3 and Figure 4 The figures show the N2 adsorption-desorption curves and pore size distribution curves for sample 1A, respectively. As can be seen from the figures, the specific surface area of ​​sample 1A is 7.3554 m². 2 / g, and contains a large number of mesoporous structures with relatively uniform pore distribution and a pore size of about 32.5078nm.

[0063] Example 2

[0064] (1) Weigh 2.3648 g of potassium permanganate, 0.4739 g of sucrose and 1.0283 g of tartaric acid and add them to 160 mL of deionized water. Set the magnetic stirring speed to 500 r / min and stir until the solid phase is completely dispersed to obtain a suspension.

[0065] (2) Slowly add a 2 g / L NaOH solution to the above suspension, adjust the pH of the suspension to 3, and continue stirring for 30 min to obtain a hydrothermal reaction solution.

[0066] (3) Transfer the above reaction solution into a reaction vessel and place it in an oven for hydrothermal reaction. Set the hydrothermal reaction temperature to 160℃ and the hydrothermal time to 20h.

[0067] (4) The hydrothermal product was centrifuged to obtain a solid product. The solid product was washed three times with deionized water and ethanol until the supernatant was neutral and then dried. The resulting cubic MnCO3 particles were named Sample 1B.

[0068] In this embodiment, the obtained sample 1B was subjected to scanning electron microscopy (SEM) testing, and the test results are as follows: Figure 5 As shown in the figure, compared with Example 1, increasing the amount of potassium permanganate and tartaric acid in the reactants, decreasing the amount of sucrose in the reactants, and adjusting the pH of the reaction solution to 3 with NaOH solution resulted in a significant increase in the particle size of sample 1B, reaching approximately 10 μm, while still maintaining a regular cubic structure. These results demonstrate that appropriately increasing the amount of reactants is feasible and can achieve large-scale preparation while maintaining the essentially unchanged cubic structure of the MnCO3 product.

[0069] Example 3

[0070] The similarities between this embodiment and Example 2 will not be repeated here; only the differences between this embodiment and Example 2 will be explained. The difference between this embodiment and Example 2 is that a 2 g / L LiOH solution was used as the pH adjustment solution to adjust the pH of the reaction solution to 3. The resulting cubic MnCO3 particles were named Sample 1C.

[0071] In this embodiment, the obtained sample 1C was subjected to scanning electron microscopy (SEM) testing, and the test results are as follows: Figure 6 As shown in the figure, when LiOH of the same concentration (2 g / L) was used instead of NaOH as the pH adjustment solution, product sample 3 still maintained a regular cubic structure. The difference was that the particle size of sample 1C was approximately 5 μm, smaller than that of sample 1B. These results indicate that, without changing the pH of the reaction solution to 3, changing the type of pH adjustment solution has little effect on the morphology of the cubic MnCO3 particles, with only a difference in particle size.

[0072] Example 4

[0073] The similarities between this embodiment and Embodiment 3 will not be repeated here; only the differences between this embodiment and Embodiment 3 will be described. The difference between this embodiment and Embodiment 3 is that the hydrothermal reaction temperature is set to 120℃ and the hydrothermal time to 36 hours. The obtained cubic MnCO3 particles are named Sample 1D.

[0074] In this embodiment, the obtained sample 1D was subjected to scanning electron microscopy (SEM) testing, and the test results are as follows: Figure 7 As shown in the figure, sample 1D has a particle size of approximately 5 μm, a smoother surface, and a highly regular cubic structure. These results indicate that appropriately lowering the hydrothermal reaction temperature and extending the hydrothermal time have little effect on the morphology of cubic MnCO3 particles.

[0075] Example 5

[0076] (1) Lithium carbonate and cubic manganese carbonate were weighed out according to a Li / Mn (molar ratio) of 0.5, and ground evenly in an agate mortar to obtain a mixed powder. The cubic manganese carbonate in this embodiment is based on the cubic manganese carbonate particles prepared in Example 2.

[0077] (2) The above mixed powder was placed in an alumina crucible and then placed in a muffle furnace for calcination. The calcination temperature was set at 360℃ and the calcination time was 300 min. The cubic manganese-based ion sieve adsorbent obtained after calcination was named Sample 2A.

[0078] In this embodiment, the obtained sample 2A was subjected to X-ray diffraction (XRD), scanning electron microscopy (SEM), and adsorption capacity tests. The test results are as follows:

[0079] Figure 8 This is the XRD pattern of sample 2A. A search revealed that sample 2A is LiMn2O4 (JCPDS PDF#35-0782), and the absence of other diffraction peaks in the spectrum indicates that the prepared sample 2A has high purity.

[0080] Figure 9 This is the SEM image of sample 2A. As shown in the image, this method can synthesize LiMn2O4 manganese-based ion sieve adsorbents with a particle size of approximately 10 μm, good dispersibility, and a regular porous cubic shape through one-step calcination.

[0081] In this embodiment, the lithium ion adsorption capacity of sample 2A was tested. The test method and process were as follows: sample 2A was soaked in 0.5 mol / L dilute hydrochloric acid for 24 hours and then dried. The mass of dried sample 2A was 20 mg, and 20 mL of 2 g / L LiOH·H2O was added to it. The sample was then allowed to stand at room temperature for 24 hours for adsorption.

[0082] The concentration of lithium ions in the solution before and after adsorption was measured using an atomic absorption spectrophotometer. The test results showed that the adsorption capacity of sample 2A for lithium ions was 41.78 mg / g.

[0083] Example 6

[0084] The difference between this embodiment and Embodiment 5 is that lithium nitrate is used as the lithium source in step (1), while the remaining steps are the same as in Embodiment 5, and therefore will not be repeated. This embodiment prepares a cubic manganese-based ion sieve adsorbent, named Sample 2B.

[0085] In this embodiment, the obtained sample 2B was subjected to X-ray diffraction (XRD) and adsorption capacity tests. The test results are as follows:

[0086] Figure 10 This is the XRD pattern of sample 2B. A search revealed that sample 2B is LiMn2O4 (JCPDS PDF#35-0782), and the absence of other diffraction peaks in the spectrum indicates that the prepared sample 2B has high purity.

[0087] In this embodiment, the lithium ion adsorption capacity of sample 2B was tested, and the test method and procedure were the same as in Example 5. The test result obtained was that the lithium ion adsorption capacity of sample 2B was 39.80 mg / g.

[0088] Example 7

[0089] The difference between this embodiment and Embodiment 5 is that lithium hydroxide is used as the lithium source in step (1), while the remaining steps are the same as in Embodiment 5, and therefore will not be repeated. This embodiment prepares a cubic manganese-based ion sieve adsorbent, named Sample 2C.

[0090] In this embodiment, the obtained sample 2C was subjected to X-ray diffraction (XRD) and adsorption capacity tests. The test results are as follows:

[0091] Figure 11 This is the XRD pattern of sample 2C. A search revealed that sample 2C is LiMn2O4 (JCPDS PDF#35-0782), and the absence of other diffraction peaks in the spectrum indicates that the prepared sample 2C has high purity.

[0092] In this embodiment, the lithium-ion adsorption capacity of sample 2C was tested, and the test method and procedure were the same as in Example 5. The test result obtained was that the lithium-ion adsorption capacity of sample 2C was 24.42 mg / g.

[0093] Example 8

[0094] The difference between this embodiment and Embodiment 5 is that the calcination temperature in step (2) is 520℃ and the calcination time is 300 min. The remaining steps are the same as in Embodiment 5, so they will not be repeated here. In this embodiment, a cubic manganese-based ion sieve adsorbent was prepared and named Sample 2D.

[0095] In this embodiment, the obtained 2D sample was subjected to X-ray diffraction (XRD) and adsorption capacity tests. The test results are as follows:

[0096] Figure 12 This is the XRD pattern of sample 2D. A search revealed that sample 2D is LiMn2O4 (JCPDS PDF#35-0782), and the absence of other diffraction peaks in the spectrum indicates that the prepared sample 2D has high purity.

[0097] In this embodiment, the lithium-ion adsorption capacity of sample 2D was tested, and the test method and procedure were the same as in Example 5. The test result obtained was that the lithium-ion adsorption capacity of sample 2D was 44.90 mg / g.

[0098] Example 9

[0099] (1) Lithium carbonate and cubic manganese carbonate were weighed out according to a Li / Mn (molar ratio) of 1, and ground evenly in an agate mortar to obtain a mixed powder. The cubic manganese carbonate in this embodiment is based on the cubic manganese carbonate particles prepared in Example 2.

[0100] (2) The above mixed powder was placed in an alumina crucible and then placed in a muffle furnace for calcination. The calcination temperature was set at 800℃ and the calcination time was 300min. The cubic manganese-based ion sieve adsorbent obtained after calcination was named Sample 2E.

[0101] In this embodiment, the obtained sample 2E was subjected to X-ray diffraction (XRD) and adsorption capacity tests. The test results are as follows:

[0102] Figure 13 This is the XRD pattern of sample 2E. A search revealed that sample 2E is LiMn2O4 (JCPDS PDF#35-0782), and the absence of other diffraction peaks in the spectrum indicates that the prepared sample 2E has high purity.

[0103] In this embodiment, the lithium ion adsorption capacity of sample 2E was tested, and the test method and procedure were the same as in Example 5. The test result obtained was that the lithium ion adsorption capacity of sample 2E was 21.08 mg / g.

[0104] In summary, the method for preparing porous cubic manganese-based lithium-ion sieve adsorbent provided in this invention involves mixing and grinding a manganese source with cubic manganese carbonate, followed by a one-step calcination to obtain a regular porous cubic manganese-based lithium-ion sieve. Compared to the two-step method of hydrothermal treatment and calcination in the prior art, the method provided by this invention is simple and easy to operate, reduces the process difficulty, and allows for better control of the porous cubic morphology of the resulting ion sieve adsorbent, thus ensuring good dispersion during the adsorption process in salt lake brine and exhibiting excellent adsorption performance.

[0105] The above description is only a specific embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A method of preparing a porous cubic manganese-based lithium-ion-sieve adsorbent, characterized by, include: S11. Potassium permanganate, sucrose, and tartaric acid are added directly to water that is being magnetically stirred. The stirring is carried out using magnetic stirring at a speed of 400 r / min to 600 r / min until the solid phase is completely dispersed to form a suspension. A pH adjustment solution is slowly added to the suspension while stirring continuously to make the pH value of the reaction solution 2.8 to 3.

2. Magnetic stirring is continued for more than 30 minutes to allow all the gas produced in the reaction to escape, thus obtaining the reaction solution. S12. Transfer the reaction solution to a reaction vessel and heat it to allow the reaction solution to undergo a hydrothermal reaction at 100℃~200℃ for 12h~36h. S13. The hydrothermal reaction product is centrifuged to obtain a solid product. The solid product is then washed and dried sequentially to prepare cubic manganese carbonate particles. S20. The lithium source and the cubic manganese carbonate particles are mixed and ground in a Li to Mn molar ratio of 0.1 to 1.6 to obtain a mixed powder. The mixed powder is then subjected to a one-step calcination treatment at a temperature of 300℃ to 800℃ and a calcination time of 60 min to 500 min to obtain a porous cubic manganese-based lithium ion sieve adsorbent.

2. The production method according to claim 1, characterized by, The lithium source is selected from one or more of lithium hydroxide, lithium nitrate, lithium chloride, and lithium carbonate.

3. The preparation method according to claim 1, characterized in that, The pH adjusting solution is selected from at least one of LiOH solution, NaOH solution, KOH solution, HCl solution, H2SO4 solution, HNO3 solution and C2H4O2 solution.

4. The production method according to any one of claims 1 to 3, characterized by, The concentration of the pH adjusting solution is 1.5 g / L to 2.5 g / L.

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