Titanium-based lithium ion sieve beta-h2tio3, method for activating the same, and use thereof

Abstract

The application provides a titanium lithium ion sieve beta-H2TiO3 and an activation method and application thereof, and relates to the technical field of precursor activation. The titanium lithium ion sieve beta-H2TiO3 is mainly obtained by activating a precursor beta-Li2TiO3 by an acidic activation solution, wherein the activation is carried out under intermittent microwave auxiliary conditions, and the acidic activation solution comprises oxalic acid and citric acid. By selecting the activation conditions and the activation solution, the total activation time of the activation method is only 8-13% of that of a common activation method, and the activation efficiency is greatly improved. While obtaining the titanium lithium ion sieve beta-H2TiO3, the technical problems of a complicated activation process, long time and low efficiency are solved, and the technical problem that the performance feedback of the product beta-Li2TiO3 cannot be quickly obtained in the production process of the precursor beta-Li2TiO3, and the synthesis process parameters cannot be adjusted in time is solved.

Description

Technical Field

[0001] This invention relates to the field of precursor activation technology, and in particular to a titanium-based lithium ion sieve β-H2TiO3, its activation method, and its application. Background Technology

[0002] Lithium, as the lightest metallic element in nature, possesses excellent physical and chemical properties, giving it high utilization value and a wide range of applications. Lithium and its salts are an important strategic resource, and its compounds are widely used in chemical, glass, ceramic, aerospace, and new energy fields, making lithium resource development and utilization a major focus.

[0003] Titanium-based lithium-ion sieves (β-H₂TiO₃) are suitable for lithium extraction from weakly alkaline brine in salt lakes. They exhibit advantages such as good stability, large adsorption capacity, and high selectivity. β-H₂TiO₃ is obtained by activating the precursor β-Li₂TiO₃ with an acidic solution. To test the performance of β-H₂TiO₃, the precursor β-Li₂TiO₃ needs to be activated to β-H₂TiO₃ first. The activation reaction is β-Li₂TiO₃ + 2H₂O + 2H₂O. + =β-H2TiO3+2Li + Activation using common inorganic acids such as hydrochloric acid or sulfuric acid takes 10-20 hours to complete, mainly for two reasons:

[0004] (1) When lithium ions and hydrogen ions coexist in the solution, these two types of ions will form competitive adsorption at the adsorption sites of the material, making it difficult for lithium ions β-Li2TiO3 on the precursor to be quickly replaced by hydrogen ions to form lithium ion sieve β-H2TiO3. The entire activation process requires replacing the activation solution 3-5 times to reduce the concentration of lithium ions in the activation solution. When the concentration of hydrogen ions remains unchanged, it is conducive to the formation of the competitive advantage of hydrogen ions.

[0005] (2) Because the hydrogen ion concentration that β-Li2TiO3 can tolerate in solution is <1 mol / L, solid β-Li2TiO3 is easily dissolved and becomes ineffective when the hydrogen ion concentration exceeds 1 mol / L. Therefore, it is impossible to increase the competitive advantage of hydrogen ions by increasing the hydrogen ion concentration in the activation solution.

[0006] The above two reasons lead to the disadvantages of the current activation method, which is that the steps are cumbersome and time-consuming. In the continuous production of the precursor β-Li2TiO3, it is impossible to quickly determine whether the performance of the produced precursor β-Li2TiO3 is qualified, and it is impossible to make timely adjustments to the production process based on the performance feedback of β-Li2TiO3, which easily leads to a large number of unqualified products in the production process.

[0007] In view of this, the present invention is hereby proposed. Summary of the Invention

[0008] The primary objective of this invention is to provide an activation method for titanium-based lithium-ion sieve β-H₂TiO₃. This activation method reduces the total activation time to only 8%-13% of conventional methods, significantly improving activation efficiency. While obtaining titanium-based lithium-ion sieve β-H₂TiO₃, it also solves the technical problems of cumbersome activation steps, long activation times, and low efficiency. Furthermore, it addresses the technical challenge of not being able to quickly obtain performance feedback of the β-Li₂TiO₃ precursor during its production, thus hindering timely adjustments to synthesis process parameters.

[0009] The second objective of this invention is to provide a titanium-based lithium ion sieve β-H2TiO3 obtained by the above-mentioned activation method of titanium-based lithium ion sieve β-H2TiO3.

[0010] The third objective of this invention is to provide an application of a titanium-based lithium ion sieve β-H2TiO3, which can be widely used in the process of lithium extraction from weakly alkaline salt lake brine.

[0011] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0012] The present invention provides an activation method for titanium-based lithium ion sieve β-H2TiO3, wherein the titanium-based lithium ion sieve β-H2TiO3 is mainly obtained by activating the precursor β-Li2TiO3 with an acidic activation solution;

[0013] The acidic activating solution includes oxalic acid and citric acid;

[0014] The activation was performed under intermittent microwave-assisted conditions.

[0015] Furthermore, the oxalic acid is oxalic acid containing water of crystallization, preferably oxalic acid dihydrate; the citric acid is citric acid containing water of crystallization, preferably citric acid monohydrate.

[0016] Furthermore, in the acidic activating solution, the mass ratio of oxalic acid dihydrate to citric acid monohydrate is 50-90:300-400.

[0017] Furthermore, during the intermittent microwave-assisted activation process, the temperature of the activation solution is ≤60℃.

[0018] Furthermore, during the activation process, the ratio of the precursor β-Li2TiO3 to the activation solution is 5-8 g / 300-400 ml.

[0019] Furthermore, the activation method includes:

[0020] (a) Preparation of activation solution: Add 50-90g of oxalic acid dihydrate solid and 300-400g of citric acid monohydrate solid to 0.8-1L of deionized water, stir thoroughly to dissolve for 10-20 minutes to obtain the activation solution;

[0021] (b) Precursor activation: The precursor β-Li2TiO3 and the activation solution were mixed at a ratio of 5-8g / 300-400ml and then subjected to intermittent microwave-assisted treatment to obtain titanium-based lithium ion sieve β-H2TiO3.

[0022] Furthermore, the microwave power of the intermittent microwave-assisted processing is 800-1200W, and the duration of the intermittent microwave-assisted processing is 0.5-2h.

[0023] Furthermore, step (b) precursor activation includes:

[0024] (b1) Take 0.3-0.4L of the activation solution obtained in step (a) and pour it into a beaker. Add 5-8g of the precursor β-Li2TiO3 powder and stir for 1-3 minutes.

[0025] (b2) Place the stirred beaker of liquid in an 800-1200W microwave oven and heat for 1-3 minutes. Then stop the microwave heating. Remove the beaker and add 50-100mL of activation solution to the beaker. Stir for 1-3 minutes.

[0026] Then, place the beaker in an 800-1200W microwave oven and heat for 2-4 minutes. Stop the microwave heating and stir for 1-3 minutes. Let the liquid in the beaker stand for 5-10 minutes, then turn on the microwave oven again and heat for 2-4 minutes. Stop the microwave heating and stir for 1-3 minutes. Let the liquid in the beaker stand for 5-10 minutes, then turn on the microwave oven again and heat for 2-4 minutes. Stop the microwave heating, remove the beaker, and you will get the liquid after intermittent microwave-assisted treatment.

[0027] (b3) The liquid material after intermittent microwave-assisted treatment in step (b2) is subjected to negative pressure suction filtration to achieve solid-liquid separation. The solid filter cake is washed with deionized water 2-4 times. The washed solid filter cake is placed in an 800-1200W microwave oven and heated for 2-4 minutes to obtain titanium-based lithium ion sieve β-H2TiO3 powder.

[0028] The present invention provides a titanium-based lithium ion sieve β-H2TiO3 obtained by activation according to the above-mentioned activation method of titanium-based lithium ion sieve β-H2TiO3.

[0029] This invention provides an application of the above-mentioned titanium-based lithium ion sieve β-H2TiO3 in the lithium extraction process of weakly alkaline salt lake brine.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] This invention provides an activation method for titanium-based lithium-ion sieve β-H₂TiO₃. The β-H₂TiO₃ is primarily obtained by activating the precursor β-Li₂TiO₃ with an acidic activation solution. The activation is carried out under intermittent microwave-assisted conditions, and the acidic activation solution includes oxalic acid and citric acid. By selecting the above activation conditions and activation solution, the total activation time of this invention is only 8%-13% of that of conventional activation methods, significantly improving activation efficiency. While obtaining titanium-based lithium-ion sieve β-H₂TiO₃, this invention solves the technical problems of cumbersome activation steps, long activation time, and low efficiency. It also addresses the technical challenge of not being able to quickly obtain performance feedback of the β-Li₂TiO₃ product during the production of the precursor β-Li₂TiO₃, thus hindering timely adjustment of synthesis process parameters.

[0032] The titanium-based lithium ion sieve β-H2TiO3 of this application can be widely used in the process of lithium extraction from weakly alkaline salt lake brine. Attached Figure Description

[0033] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0034] Figure 1 SEM images of the precursor β-Li2TiO3 before activation and the titanium-based lithium ion sieve β-H2TiO3 after activation, provided in Example 1 of this application;

[0035] Figure 2 XRD patterns of the precursor β-Li2TiO3 before activation and the titanium-based lithium ion sieve β-H2TiO3 after activation, provided in Example 1 of this application;

[0036] Figure 3 SEM images of the precursor β-Li2TiO3 before activation and the titanium-based lithium ion sieve β-H2TiO3 after activation, provided in Example 2 of this application;

[0037] Figure 4 XRD patterns of the precursor β-Li2TiO3 before activation and the titanium-based lithium ion sieve β-H2TiO3 after activation, provided in Example 2 of this application;

[0038] Figure 5 The stability test diagram of the precursor provided in Experimental Example 1 of this application after 20 activations. Detailed Implementation

[0039] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] According to one aspect of the present invention, an activation method for titanium-based lithium ion sieve β-H2TiO3 is provided, wherein the titanium-based lithium ion sieve β-H2TiO3 is mainly obtained by activating the precursor β-Li2TiO3 with an acidic activation solution;

[0041] The acidic activating solution includes oxalic acid and citric acid;

[0042] The activation was performed under intermittent microwave-assisted conditions.

[0043] The present invention provides an activation method for titanium-based lithium-ion sieve β-H2TiO3. The titanium-based lithium-ion sieve β-H2TiO3 is mainly obtained by activating the precursor β-Li2TiO3 with an acidic activation solution. The activation is carried out under intermittent microwave-assisted conditions, and the acidic activation solution includes oxalic acid and citric acid. Through the above activation process and the selection of the activation solution, the activation method for titanium-based lithium-ion sieve β-H2TiO3 of this application has the following advantages compared to existing conventional activation methods:

[0044] (1) Oxalic acid and citric acid are weak acids and there is an ionization equilibrium process in the solution. The concentration of oxalic acid and citric acid added to the activation solution is relatively high, which will not cause the concentration of free hydrogen ions in the solution to be greater than 1 mol / L, which is beneficial to suppress the acid solubility of the precursor β-Li2TiO3.

[0045] Note: The concentration of oxalic acid with a higher concentration is 0.5-0.7 mol / L, and the concentration of citric acid with a higher concentration is 1.78-1.9 mol / L.

[0046] (2) Adding high concentrations of oxalic acid and citric acid to the solution can reduce the frequency of acid replenishment. This is because when the hydrogen ion concentration in the solution is low, oxalic acid and citric acid will automatically ionize to produce hydrogen ions, thus achieving real-time replenishment of hydrogen ions. This is highly effective and has few side effects.

[0047] (3) Oxalate and citrate ions have a strong complexing effect on lithium ions. When lithium ions at the precursor β-Li2TiO3 site are replaced by hydrogen ions into the solution, oxalate and citrate ions in the solution will automatically complex lithium ions to form complexed ions (such as LiC2O4). + C6H5O7Li2 +or C6H6O7Li + The concentration of free lithium ions in the solution will decrease sharply, and they will not be re-adsorbed by the titanium-based lithium ion sieve β-H2TiO3 to become β-Li2TiO3, which greatly improves the activation efficiency of the precursor β-Li2TiO3.

[0048] (4) H during acidification + and Li + The proton exchange process is slow under normal heating; to increase the acidification rate, the proton exchange rate needs to be increased. Studies have shown that microwave radiation can lower the activation energy of a reaction, significantly increasing the reaction rate and accelerating reactions that normally occur slowly. Microwave-assisted oxidation facilitates the energy gain of hydrogen ions in solution, increasing their migration rate and rapidly replacing lithium ions at the β-Li₂TiO₃ sites of the precursor, thus improving activation efficiency.

[0049] (5) Intermittent microwave assistance helps to control the temperature of the activation solution, keeping the temperature below 60℃, which improves the activation efficiency and greatly reduces the solubility loss of β-Li2TiO3 in acidic solution due to excessive temperature.

[0050] (6) Using hydrochloric acid or sulfuric acid as the activation solution and using ordinary water bath heating for activation, it takes 10-20 hours to complete the activation; using oxalic acid (H2C2O4) and citric acid (C6H8O7) solution as the activation solution and adding intermittent microwave assistance, it only takes 0.5-2 hours to complete the activation, which greatly improves the timeliness.

[0051] Therefore, the total activation time of the activation method of this invention is only 8%-13% of that of ordinary activation methods, greatly improving the activation efficiency. While obtaining titanium-based lithium-ion sieves β-H₂TiO₃, it solves the technical problems of cumbersome activation process steps, long time, and low efficiency. It also solves the technical problem of not being able to quickly obtain performance feedback of the product β-Li₂TiO₃ during the production of the precursor β-Li₂TiO₃, thus preventing timely adjustment of synthesis process parameters. It achieves rapid detection of the performance of the precursor β-Li₂TiO₃, and the operation is simple and quick, facilitating widespread application and showing great promise for large-scale production of titanium-based lithium-ion sieves.

[0052] In a preferred embodiment of the present invention, the oxalic acid is oxalic acid containing water of crystallization, preferably oxalic acid dihydrate; the citric acid is citric acid containing water of crystallization, preferably citric acid monohydrate.

[0053] As a preferred embodiment, oxalic acid containing water of crystallization and citric acid containing water of crystallization can effectively improve the solubility of oxalic acid and citric acid in the activation solution.

[0054] In the preferred embodiment described above, the mass ratio of oxalic acid dihydrate to citric acid monohydrate in the acidic activating solution is 50-90:300-400.

[0055] As a preferred embodiment, the above-mentioned mass ratio of oxalic acid dihydrate to citric acid monohydrate exhibits better activation efficiency. However, when the oxalic acid content in the above mass ratio is too high, the ionization coefficient of oxalic acid is 5.4 × 10⁻⁶. -2 The ionization coefficient of citric acid is 7.4 × 10⁻⁶. -4 In other words, oxalic acid is much more acidic than citric acid. If the amount of oxalic acid added is too high, it will lead to excessively high acidity in the activation solution, which can easily damage the crystal structure of the titanium-based lithium ion sieve. In addition, since citric acid has a stronger complexing ability for lithium ions than oxalate, if the citric acid content in the activation solution is low, it will result in a situation where more acid is used but the activation rate is low during the activation process. At the same time, when the mass ratio of oxalic acid dihydrate to citric acid monohydrate is too low, the amount of oxalic acid in the solution will be small, resulting in a weaker acidity in the activation solution, which will also reduce the activation efficiency of the titanium-based lithium ion sieve.

[0056] In a preferred embodiment of the present invention, the temperature of the activation solution is ≤60°C during the intermittent microwave-assisted activation process.

[0057] As a preferred embodiment, in the intermittent microwave-assisted activation process, intermittent microwave assistance is beneficial for controlling the temperature of the activation solution, keeping the temperature of the activation solution below 60°C. While improving the activation efficiency, it greatly reduces the solubility loss of β-Li2TiO3 in acidic solutions caused by excessively high temperatures.

[0058] In a preferred embodiment of the present invention, the ratio of precursor β-Li2TiO3 to activation solution during the activation process is 5-8 g / 300-400 ml.

[0059] In a preferred embodiment, if the ratio of precursor β-Li2TiO3 to activation solution is too high during the activation process, the viscosity of the solution will be too high, reducing the contact efficiency between the precursor β-Li2TiO3 and the acidic solution. This can easily lead to insufficient or uneven activation, affecting the activation effect of the precursor β-Li2TiO3. Conversely, if the ratio of precursor β-Li2TiO3 to activation solution is too low, excessive activation solution will be added, which will not only waste the activation solution but also affect the efficiency of solid-liquid separation after activation, thus reducing the activation efficiency.

[0060] In a preferred embodiment of the present invention, the activation method includes:

[0061] (a) Preparation of activation solution: Add 50-90g of oxalic acid dihydrate solid and 300-400g of citric acid monohydrate solid to 0.8-1L of deionized water, stir thoroughly to dissolve for 10-20 minutes to obtain the activation solution;

[0062] (b) Precursor activation: The precursor β-Li2TiO3 and the activation solution were mixed at a ratio of 5-8g / 300-400ml and then subjected to intermittent microwave-assisted treatment to obtain titanium-based lithium ion sieve β-H2TiO3.

[0063] In the preferred embodiment described above, the microwave power of the intermittent microwave-assisted processing is 800-1200W, and the duration of the intermittent microwave-assisted processing is 0.5-2h.

[0064] In the preferred embodiment described above, step (b) precursor activation includes:

[0065] (b1) Take 0.3-0.4L of the activation solution obtained in step (a) and pour it into a beaker. Add 5-8g of the precursor β-Li2TiO3 powder and stir for 1-3 minutes.

[0066] (b2) Place the stirred beaker of liquid in an 800-1200W microwave oven and heat for 1-3 minutes. Then stop the microwave heating. Remove the beaker and add 50-100mL of activation solution to the beaker. Stir for 1-3 minutes.

[0067] Then, place the beaker in an 800-1200W microwave oven and heat for 2-4 minutes. Stop the microwave heating and stir for 1-3 minutes. Let the liquid in the beaker stand for 5-10 minutes, then turn on the microwave oven again and heat for 2-4 minutes. Stop the microwave heating and stir for 1-3 minutes. Let the liquid in the beaker stand for 5-10 minutes, then turn on the microwave oven again and heat for 2-4 minutes. Stop the microwave heating, remove the beaker, and you will get the liquid after intermittent microwave-assisted treatment.

[0068] It should be noted that, through the above-described intermittent microwave heating step, this application can effectively control the temperature of the activation solution during the activation process, maintaining the temperature of the activation solution at ≤60℃.

[0069] (b3) The liquid material after intermittent microwave-assisted treatment in step (b2) is subjected to negative pressure suction filtration to achieve solid-liquid separation. The solid filter cake is washed with deionized water 2-4 times. The washed solid filter cake is placed in an 800-1200W microwave oven and heated for 2-4 minutes to obtain titanium-based lithium ion sieve β-H2TiO3 powder.

[0070] According to one aspect of the present invention, a titanium-based lithium ion sieve β-H2TiO3 is obtained by activation according to the above-described activation method for titanium-based lithium ion sieve β-H2TiO3.

[0071] The titanium-based lithium ion sieve β-H2TiO3 provided by the present invention is mainly obtained by activation of the titanium-based lithium ion sieve β-H2TiO3 by the above-mentioned activation method.

[0072] According to one aspect of the present invention, the application of the above-mentioned titanium-based lithium ion sieve β-H2TiO3 in the lithium extraction process of weakly alkaline salt lake brine.

[0073] The titanium-based lithium ion sieve β-H2TiO3 of this application can be widely used in the process of lithium extraction from weakly alkaline salt lake brine.

[0074] The technical solution of the present invention will be further described below with reference to the embodiments.

[0075] Example 1

[0076] An activation method for titanium-based lithium-ion sieve β-H2TiO3 includes the following steps:

[0077] (I) Preparation of activation solution:

[0078] Add 50g of oxalic acid dihydrate (H2C2O4·2H2O) solid to 0.8L of deionized water, then add 300g of citric acid monohydrate (C6H8O7·H2O) solid, stir thoroughly to dissolve for 10 minutes, and set aside for use.

[0079] (II) Precursor activation:

[0080] 1. Pour 0.3L of the above activation solution into a beaker, add 5g of precursor β-Li2TiO3 powder, and stir with a glass rod for 1min;

[0081] 2. Place the beaker of liquid in an 800W microwave oven and heat for 1 minute, then stop the microwave heating; remove the beaker, add 50mL of the above activation solution to the beaker, and stir with a glass rod for 1 minute;

[0082] Then, the beaker was placed in an 800W microwave oven and heated for 2 minutes. The microwave heating was then stopped, and the mixture was stirred with a glass rod for 1 minute. The liquid in the beaker was allowed to stand for 5 minutes, and then the microwave heating was turned on again and heated for 2 minutes. The microwave heating was then stopped, and the mixture was stirred with a glass rod for 1 minute. The liquid in the beaker was allowed to stand for 5 minutes, and then the microwave heating was turned on again and heated for 2 minutes. The microwave heating was then stopped. The beaker was then removed, and the liquid after intermittent microwave-assisted treatment was obtained.

[0083] 3. The liquid material is filtered by negative pressure suction to achieve solid-liquid separation. The solid filter cake is washed twice with deionized water. The washed solid filter cake is placed in an 800W microwave oven and heated for 2 minutes to obtain dry titanium-based lithium ion sieve β-H2TiO3 powder.

[0084] (III) The activation of the precursor β-Li2TiO3 powder is complete, and the titanium-based lithium ion sieve β-H2TiO3 powder will undergo subsequent performance testing.

[0085] Figure 1 The images show SEM images of the precursor β-Li₂TiO₃ before activation and the titanium-based lithium-ion sieve β-H₂TiO₃ after activation in this embodiment. Wherein: Figure 1 (a) is a SEM image of the precursor β-Li2TiO3 before activation in this embodiment; Figure 1 (b) is a SEM image of the activated titanium-based lithium ion sieve β-H2TiO3 in this embodiment.

[0086] Depend on Figure 1 It can be seen that there is no significant difference in the surface morphology of the two powders before and after activation, with a particle size of approximately 200-800 nm.

[0087] Figure 2 The images show the XRD patterns of the precursor β-Li₂TiO₃ before activation and the titanium-based lithium-ion sieve β-H₂TiO₃ after activation in this embodiment. Wherein: Figure 2 The XRD pattern of the precursor β-Li2TiO3 before activation using oxalic acid (H2C2O4) and citric acid (C6H8O7) solutions as activation solutions and with intermittent microwave-assisted activation. Figure 2 The XRD pattern of β-H2TiO3, a titanium-based lithium-ion sieve, is obtained by using oxalic acid (H2C2O4) and citric acid (C6H8O7) solutions as activation solutions and an intermittent microwave-assisted method.

[0088] Depend on Figure 2 XRD patterns of the precursor β-Li2TiO3 and titanium-based lithium ion sieve β-H2TiO3 show that after activation of the precursor β-Li2TiO3, the diffraction peaks of the titanium-based lithium ion sieve β-H2TiO3 become broader and the intensity decreases significantly. The (-133) and (-206) peaks disappear, and the (002) diffraction peak shifts slightly to the right. This proves that using oxalic acid (H2C2O4) and citric acid (C6H8O7) solutions as activation liquids and adding intermittent microwave assistance can efficiently activate the precursor β-Li2TiO3, transforming the powder crystal form from β-Li2TiO3 to β-H2TiO3.

[0089] (iv) Comparison with existing activation methods:

[0090] The powder of the same mass as in this embodiment was activated using an existing activation method (using hydrochloric acid as the activation solution and a water bath for heating). The specific scheme is as follows:

[0091] Add 5g of the precursor and 300ml of deionized water to a beaker, then slowly add 16% mol / L hydrochloric acid eluent. Stir at 50℃ for 1h, maintaining the pH of the slurry between 1.7 and 2.0 throughout the process. Stop adding acid after the pH stabilizes for 1h. Centrifuge the resulting slurry and test the TDS value using a conductivity meter. Centrifuge until TDS ≤ 100mg / L, then begin the second acidification process. Repeat the first acidification process, stopping acid addition after the pH stabilizes for 1h, and then perform a second centrifugation. Centrifuge until TDS ≤ 100mg / L, then begin the third acidification process. After the third acidification, centrifuge until TDS ≤ 100mg / L, then end the acidification process. Dry the obtained solid in a 50℃ oven to obtain β-H2TiO3.

[0092] The following table compares the effects of this embodiment with the above-described conventional activation method:

[0093]

[0094] As shown in the table above, for the same mass of powder, using a conventional activation method, such as using hydrochloric acid as the activation solution and heating in a water bath, requires a total activation time of 12 hours and an activation rate of 98.4%. However, using oxalic acid (H2C2O4) and citric acid (C6H8O7) solutions as the activation solution, coupled with intermittent microwave-assisted activation, requires a total activation time of 1 hour and an activation rate of 99.6%. Therefore, under the same activation conditions, the activation method of this invention requires only 8.3% of the total activation time of the conventional activation method, greatly improving the activation efficiency.

[0095] Example 2

[0096] An activation method for titanium-based lithium-ion sieve β-H2TiO3 includes the following steps:

[0097] (I) Preparation of activation solution:

[0098] Add 90g of oxalic acid dihydrate (H2C2O4·2H2O) solid to 1L of deionized water, then add 400g of citric acid monohydrate (C6H8O7·H2O) solid, stir thoroughly to dissolve for 20 minutes, and set aside for use.

[0099] (II) Precursor activation:

[0100] 1. Pour 0.4L of the above activation solution into a beaker, add 8g of precursor β-Li2TiO3 powder, and stir with a glass rod for 3min;

[0101] 2. Place the beaker of liquid in a 1200W microwave oven and heat for 3 minutes. Then stop the microwave heating. Remove the beaker, add 100mL of the above activation solution to the beaker, and stir with a glass rod for 3 minutes.

[0102] Then, the beaker was placed in a 1200W microwave oven and heated for 4 minutes. After stopping the microwave heating, the mixture was stirred with a glass rod for 3 minutes. The mixture in the beaker was allowed to stand for 10 minutes, and then heated in a 1200W microwave oven for 4 minutes. After stopping the microwave heating, the mixture was stirred with a glass rod for 3 minutes. The mixture in the beaker was allowed to stand for 10 minutes, and then heated in a 1200W microwave oven for 4 minutes. After stopping the microwave heating, the beaker was removed, and the mixture after intermittent microwave-assisted treatment was obtained.

[0103] 3. The liquid material is filtered by negative pressure suction to achieve solid-liquid separation. The solid filter cake is washed 4 times with deionized water. The washed solid filter cake is placed in a 1200W microwave oven and heated for 4 minutes to obtain dry titanium-based lithium ion sieve β-H2TiO3 powder.

[0104] (III) The activation of the precursor β-Li2TiO3 powder is complete, and the titanium-based lithium ion sieve β-H2TiO3 powder will undergo subsequent performance testing.

[0105] Figure 3 The images show SEM images of the precursor β-Li₂TiO₃ before activation and the titanium-based lithium-ion sieve β-H₂TiO₃ after activation in this embodiment. Wherein: Figure 3 Image (a) shows a SEM image of the precursor β-Li₂TiO₃ before activation using oxalic acid (H₂C₂O₄) and citric acid (C₆H₈O₇) solutions as activation media and with intermittent microwave-assisted activation. Figure 3 (b) shows the SEM image of the titanium-based lithium ion sieve β-H2TiO3 after activation using oxalic acid (H2C2O4) and citric acid (C6H8O7) solutions as activation liquids and an intermittent microwave-assisted method.

[0106] Depend on Figure 3 It can be seen that there is no significant difference in the surface morphology of the two powders before and after activation, with a particle size of approximately 200-800 nm.

[0107] Figure 4 The images show the XRD patterns of the precursor β-Li₂TiO₃ before activation and the titanium-based lithium-ion sieve β-H₂TiO₃ after activation in this embodiment. Wherein: Figure 4The XRD pattern of the precursor β-Li2TiO3 before activation using oxalic acid (H2C2O4) and citric acid (C6H8O7) solutions as activation solutions and with intermittent microwave-assisted activation. Figure 4 The XRD pattern of β-H2TiO3, a titanium-based lithium-ion sieve, is obtained by using oxalic acid (H2C2O4) and citric acid (C6H8O7) solutions as activation solutions and an intermittent microwave-assisted method.

[0108] Depend on Figure 4 XRD patterns of the precursor β-Li2TiO3 and titanium-based lithium ion sieve β-H2TiO3 show that after activation of the precursor β-Li2TiO3, the diffraction peaks of the titanium-based lithium ion sieve β-H2TiO3 become broader and the intensity decreases significantly. The (-133) and (-206) peaks disappear, and the (002) diffraction peak shifts slightly to the right. This proves that using oxalic acid (H2C2O4) and citric acid (C6H8O7) solution as activation liquid and adding intermittent microwave assistance can efficiently activate the precursor β-Li2TiO3, transforming the powder crystal form from β-Li2TiO3 to β-H2TiO3.

[0109] (iv) Comparison with existing activation methods:

[0110] The powder of the same mass as in this embodiment was activated using an existing activation method (using hydrochloric acid as the activation solution and a water bath for heating). The specific scheme is as follows:

[0111] Add 8g of the precursor and 400ml of deionized water to a beaker, then slowly add 16% mol / L hydrochloric acid eluent. Stir at 50℃ for 1h, maintaining the pH of the slurry between 1.7 and 2.0 during the process. Stop adding acid after the pH of the slurry stabilizes for 1h. Centrifuge the resulting slurry and test the TDS value of the solution using a conductivity meter. Centrifugation ends when TDS ≤ 100mg / L, and the second acidification begins. Repeat the first acidification process, stopping acid addition after the pH of the slurry stabilizes for 1h, and then perform a second centrifugation. Centrifugation ends when TDS ≤ 100mg / L, and the third acidification begins. After acidification, start a third centrifugation, ending the acidification process when TDS ≤ 100mg / L. Dry the obtained solid in a 50℃ oven to obtain β-H2TiO3.

[0112] The following table compares the effects of this embodiment with the above-described conventional activation method:

[0113]

[0114] As shown in the table above, for the same mass of powder, using a conventional activation method, such as using hydrochloric acid as the activation solution and heating in a water bath, requires a total activation time of 11.5 hours and an activation rate of 97.3%. However, using oxalic acid (H2C2O4) and citric acid (C6H8O7) solutions as the activation solution, coupled with intermittent microwave-assisted activation, requires a total activation time of 1.5 hours and an activation rate of 99.8%. It can be seen that, under the same activation conditions, the activation method of this invention requires only 13% of the total activation time of the conventional activation method, greatly improving the activation efficiency.

[0115] Experimental Example 1

[0116] This experimental example uses the activation solution and precursor activation method described in Example 1 to activate 20 portions (5g each) of the β-Li₂TiO₃ precursor powder, and examines the stability of the activation degree and activation time. The results are as follows: Figure 5 As shown.

[0117] Figure 5 The stability test diagram of the precursor after 20 activations provided for this experimental example.

[0118] Depend on Figure 5 It can be seen that in the 20 activation experiments conducted in this example, the total activation time for each experiment was 0.9-1.5 hours, and the activation rate was 99.1%-99.8%. This proves that the activation method of this invention has extremely high stability and scientific validity.

[0119] Comparative Example 1

[0120] An activation method for titanium-based lithium-ion sieve β-H2TiO3 includes the following steps:

[0121] (I) Preparation of activation solution:

[0122] Add 50g of oxalic acid dihydrate (H2C2O4·2H2O) solid to 0.8L of deionized water, then add 300g of citric acid monohydrate (C6H8O7·H2O) solid, stir thoroughly to dissolve for 10 minutes, and set aside for use.

[0123] (II) Precursor activation:

[0124] 1. Pour 0.3L of the above activation solution into a beaker, add 5g of precursor β-Li2TiO3 powder, and stir with a glass rod for 1min;

[0125] 2. Place the beaker of liquid in a 1200W microwave oven and heat continuously for 15 minutes, then stop the microwave heating; remove the beaker to obtain the liquid after continuous microwave-assisted treatment;

[0126] The liquid material was filtered under negative pressure to achieve solid-liquid separation. The solid filter cake was washed four times with deionized water. The washed solid filter cake was then heated in a 1200W microwave oven for 4 minutes to obtain dry titanium-based lithium ion sieve β-H2TiO3 powder.

[0127] Testing revealed that the activation efficiency of the titanium-based lithium ion sieve β-H2TiO3 powder prepared in this comparative example was only 41.5%, which is far lower than the activation efficiency (>99%) of the intermittent microwave heating method used in this application.

[0128] Comparative Example 2

[0129] An activation method for titanium-based lithium-ion sieve β-H2TiO3 includes the following steps:

[0130] (I) Preparation of activation solution:

[0131] Add 200 mL of acetic acid (H4C2O2) solution to 0.8 L of deionized water, stir thoroughly, and set aside for later use.

[0132] (II) Precursor activation: Same as in Example 1.

[0133] Testing revealed that the activation efficiency of the titanium-based lithium ion sieve β-H2TiO3 powder prepared in this comparative example was only 64.5%, which is far lower than the activation efficiency (>99%) of the embodiment using the oxalic acid + citric acid mixed acid system in this application.

[0134] Comparative Example 3

[0135] An activation method for titanium-based lithium-ion sieve β-H2TiO3 includes the following steps:

[0136] (I) Preparation of activation solution:

[0137] Add 40g of oxalic acid dihydrate (H2C2O4·2H2O) solid to 0.8L of deionized water, then add 400g of citric acid monohydrate (C6H8O7·H2O) solid, stir thoroughly to dissolve for 10 minutes, and set aside for use.

[0138] (II) Precursor activation: Same as in Example 1.

[0139] Testing revealed that the titanium-based lithium-ion sieve β-H2TiO3 powder prepared in this comparative example had an activation time of 5.5 h due to the low addition of oxalic acid in the activation solution, resulting in excessively low acidity of the solution. This is significantly longer than the activation time (0.9-1.5 h) of the embodiment using a mixed acid system of oxalic acid and citric acid in this application.

[0140] Comparative Example 4

[0141] An activation method for titanium-based lithium-ion sieve β-H2TiO3 includes the following steps:

[0142] (I) Preparation of activation solution:

[0143] Add 100g of oxalic acid dihydrate (H2C2O4·2H2O) solid to 0.8L of deionized water, then add 300g of citric acid monohydrate (C6H8O7·H2O) solid, stir thoroughly to dissolve for 10 minutes, and set aside for use.

[0144] (II) Precursor activation: Same as in Example 1.

[0145] Testing revealed that the titanium-based lithium ion sieve β-H2TiO3 powder prepared in this comparative example had a high acidity in the solution due to the high amount of oxalic acid added in the activation solution, which damaged the crystal structure of the titanium-based lithium ion sieve.

[0146] Comparative Example 5

[0147] An activation method for titanium-based lithium-ion sieve β-H2TiO3 includes the following steps:

[0148] (I) Preparation of activation solution:

[0149] Add 150g of solid oxalic acid dihydrate (H2C2O4·2H2O) to 0.8L of deionized water, stir thoroughly to dissolve for 10 minutes, and set aside for later use.

[0150] (II) Precursor activation: Same as in Example 1.

[0151] Testing revealed that the titanium-based lithium ion sieve β-H2TiO3 powder prepared in this comparative example had a low activation rate of only 81% due to the presence of only oxalic acid in the activation solution. This is significantly lower than the activation efficiency (>99%) achieved using a mixed acid system of oxalic acid and citric acid.

[0152] Comparative Example 6

[0153] An activation method for titanium-based lithium-ion sieve β-H2TiO3 includes the following steps:

[0154] (I) Preparation of activation solution:

[0155] Add 350g of citric acid monohydrate (C6H8O7·H2O) solid to 0.8L of deionized water, stir thoroughly to dissolve for 10 minutes, and set aside for later use.

[0156] (II) Precursor activation: Same as in Example 1.

[0157] Testing revealed that the titanium-based lithium ion sieve β-H2TiO3 powder prepared in this comparative example had an activation time of 6 hours due to the low acidity of the solution caused by the presence of only citric acid in the activation solution. This time was significantly longer than the activation time (0.9-1.5 hours) of the embodiment using a mixed acid system of oxalic acid and citric acid.

[0158] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for activating a titanium-based lithium-ion sieve β-H₂TiO₃, characterized in that, The titanium-based lithium ion sieve β-H2TiO3 is obtained by activating the precursor β-Li2TiO3 with an acidic activation solution; The acidic activating solution includes oxalic acid and citric acid; The activation was performed under intermittent microwave-assisted conditions; The activation method includes the following steps: (a) Preparation of activation solution: Add 50-90g of oxalic acid dihydrate solid and 300-400g of citric acid monohydrate solid to 0.8-1L of deionized water, stir thoroughly to dissolve for 10-20 minutes to obtain activation solution; (b) Precursor activation: The precursor β-Li2TiO3 and the activation solution were stirred and mixed at a material-to-liquid ratio of 5~8g / 300~400ml, and then subjected to intermittent microwave-assisted treatment to obtain titanium-based lithium ion sieve β-H2TiO3; During the intermittent microwave-assisted activation process, the temperature of the activation solution is ≤60℃; The microwave power of the intermittent microwave-assisted processing is 800-1200W, and the duration of the intermittent microwave-assisted processing is 0.5-2h.

2. The activation method for titanium-based lithium ion sieve β-H2TiO3 according to claim 1, characterized in that, The precursor activation step (b) includes the following steps: (b1) Take 0.3-0.4L of the activation solution obtained in step (a) and pour it into a beaker. Add 5-8g of the precursor β-Li2TiO3 powder and stir with a glass rod for 1-3 minutes. (b2) Place the stirred beaker of liquid in an 800-1200W microwave oven and heat for 1-3 minutes, then stop microwave heating; Remove the beaker, add 50-100 mL of activation solution to the beaker, and stir with a glass rod for 1-3 minutes; Then, place the beaker in an 800-1200W microwave oven and heat for 2-4 minutes. Stop the microwave heating and stir with a glass rod for 1-3 minutes. Let the liquid in the beaker stand for 5-10 minutes, then turn on the microwave oven at 800-1200W and heat for 2-4 minutes. Stop the microwave heating and stir with a glass rod for 1-3 minutes. Let the liquid in the beaker stand for 5-10 minutes, then turn on the microwave oven at 800-1200W and heat for 2-4 minutes. Stop the microwave heating, remove the beaker, and you will get the liquid after intermittent microwave-assisted treatment. (b3) The liquid material after intermittent microwave-assisted treatment in step (b2) is subjected to negative pressure suction filtration to achieve solid-liquid separation. The solid filter cake is washed with deionized water 2-4 times. The washed solid filter cake is placed in an 800-1200W microwave oven and heated for 2-4 minutes to obtain titanium-based lithium ion sieve β-H2TiO3 powder.

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