A method for rapidly preparing lithium ion sieve adsorbent based on joule heat radiation effect

Abstract

The application relates to a method for rapidly preparing a lithium ion sieve adsorbent based on a Joule heat radiation effect, and relates to a method for rapidly preparing a lithium ion sieve adsorbent.The application aims to solve the technical problems of the existing HTO type titanium lithium ion sieve adsorbent preparation process, such as the long-time solid-phase calcination of lithium titanate precursors in the precursor forming stage, the limited external heat transfer efficiency and the insufficient short-process preparation capacity.The application utilizes the Joule heat radiation effect of the electrically conductive heating body under the electrification condition to rapidly heat treat a precursor mixture composed of a lithium source and a titanium source, so that the precursor mixture forms acid-exchangeable lithium titanate precursors in a short time; then the obtained lithium titanate precursors are subjected to acid exchange and lithium removal treatment, and the HTO type lithium ion sieve adsorbent is obtained.The prepared HTO type lithium ion sieve adsorbent can be used for the selective adsorption and recovery of lithium ions in salt lake brine, seawater, geothermal water or lithium-containing wastewater.

Description

Technical Field

[0001] This invention relates to a method for rapidly preparing lithium-ion sieve adsorbents. Background Technology

[0002] Lithium resources are crucial raw materials for new energy batteries, energy storage systems, functional materials, and related chemical products. With the development of the new energy industry, the demand for lithium resources continues to increase. Salt lake brine, seawater, geothermal water, and some industrial lithium-containing wastewater contain a certain amount of lithium resources. However, these liquid lithium resources are usually accompanied by multiple coexisting ions such as sodium, potassium, magnesium, and calcium, resulting in relatively low lithium concentrations and complex ionic compositions. Therefore, it is necessary to develop lithium extraction materials with high selectivity and stability.

[0003] Adsorption methods are considered an important method for lithium extraction from lithium-containing water resources due to their relatively simple process, applicability to low-concentration lithium-containing water bodies, good selectivity, and recyclable materials. Lithium-ion sieve adsorbents are a class of inorganic adsorbent materials that utilize specific crystal structures to achieve selective adsorption and desorption of lithium ions. Among them, titanium-based lithium-ion sieves have application potential in lithium extraction from brine, seawater, and other lithium-containing water bodies due to their stable titanium-oxygen framework, low titanium dissolution loss, good acid resistance, and stable recycling performance.

[0004] H2TiO3 type titanium-based lithium-ion sieves (hereinafter referred to as HTO adsorbents) are typically obtained by acid exchange delithiation of lithium titanate precursors. Existing methods for preparing lithium titanate precursors often employ traditional external heating methods such as muffle furnaces, tube furnaces, and roller kilns for solid-state calcination, causing the lithium and titanium sources to undergo a solid-state reaction at high temperatures for an extended period. While these methods can form lithium titanate precursors, they usually require lengthy heating, holding, and cooling processes. The heat treatment time during precursor formation is prolonged, external heat transfer efficiency is limited, and short-process preparation capabilities are insufficient. For HTO type lithium-ion sieves, the quality of precursor formation affects the removal of lithium ions and the entry of hydrogen ions during subsequent acid exchange, thus influencing the effective exchange sites and lithium-ion adsorption performance of the resulting lithium-ion sieve adsorbent.

[0005] Joule heating technology enables the rapid conversion of electrical energy into heat energy within a conductive heating element, characterized by rapid heating, concentrated heat input, and short processing time. For precursor mixtures composed of lithium and titanium sources, Joule radiation heating can serve as an alternative heat treatment method to the traditional furnace calcination step. Through the rapid heat input generated by the conductive heating element, the precursor mixture can achieve the thermal process required to form the lithium titanate precursor in a shorter time. Unlike traditional furnaces that gradually heat materials from the external environment, the value of Joule radiation heating lies in shortening the heat treatment time of the precursor formation stage and improving the preparation efficiency of this key heat treatment unit.

[0006] However, existing methods for preparing HTO-type titanium-based lithium-ion sieve adsorbents lack a process for rapidly forming a lithium titanate precursor using the Joule thermal radiation effect, followed by acid exchange to prepare the HTO-type lithium-ion sieve adsorbent. Therefore, it is necessary to develop a rapid preparation method for lithium-ion sieve adsorbents that can shorten the lithium titanate precursor formation time, avoid lattice densification and limited acid exchange caused by excessive heat treatment, and maintain the selective adsorption performance of lithium ions. Summary of the Invention

[0007] The present invention aims to solve the technical problems of existing HTO-type titanium-based lithium-ion sieve adsorbents, such as reliance on long-term solid-state calcination in traditional furnaces during the lithium titanate precursor formation stage, limited external heat transfer efficiency, and insufficient short-process preparation capability. Instead, it provides a method for rapidly preparing lithium-ion sieve adsorbents based on the Joule thermal radiation effect.

[0008] The method for rapidly preparing lithium-ion sieve adsorbents based on the Joule thermal radiation effect of the present invention is carried out according to the following steps:

[0009] 1. Mix lithium source and titanium source to obtain precursor mixture; place precursor mixture in Joule thermal radiation heating area, and rapidly heat treat precursor mixture through Joule thermal radiation effect generated by conductive heating element to cause solid-phase reaction of lithium source and titanium source to form lithium titanate precursor.

[0010] 2. The lithium titanate precursor prepared in step 1 is added to an acid solution for acid exchange delithiation treatment, so that some of the lithium ions in the lithium titanate precursor are replaced by hydrogen ions; after the acid exchange is completed, solid-liquid separation, washing and drying are performed in sequence to obtain HTO type lithium ion sieve adsorbent.

[0011] The method provided by this invention does not simply replace traditional furnace heating with ordinary electric heating, nor does it merely promote the reaction of lithium and titanium sources by extending the high-temperature calcination time. Instead, it utilizes the Joule thermal radiation effect generated by a conductive heating element under energized conditions to rapidly heat-treat the precursor mixture composed of lithium and titanium sources, enabling the precursor mixture to form an acid-exchangeable lithium titanate precursor in a short time. Subsequently, the obtained lithium titanate precursor undergoes acid exchange delithiation treatment, so that at least part of the lithium ions in the lithium titanate precursor are replaced by hydrogen ions, resulting in an HTO-type lithium ion sieve adsorbent.

[0012] The Joule thermal radiation effect described in this invention refers to the heat generated by the resistive heating element under energized conditions, which is then transferred to the precursor mixture primarily through thermal radiation or through a coupling of thermal radiation and thermal conduction. This allows the precursor mixture to reach the thermal input required for the formation of lithium titanate precursors within a short time. The conductive heating element and the precursor mixture are spaced apart. By adjusting the current, voltage, output power, processing temperature, processing time, and the relative position or loading method between the conductive heating element and the precursor mixture, the heating process of the precursor mixture and the formation state of the lithium titanate precursor can be controlled.

[0013] The HTO-type lithium-ion sieve adsorbent prepared in this invention can be used for the selective adsorption and recovery of lithium ions in salt lake brine, seawater, geothermal water, or lithium-containing wastewater. After adsorption, the adsorbent can be desorbed and regenerated using acid solution or other desorbents, and then recycled for the adsorption and recovery of lithium ions in lithium-containing water bodies.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] First, this invention utilizes the Joule thermal radiation effect to rapidly prepare lithium titanate precursors, which can shorten the heating and holding time required by traditional solid-phase calcination.

[0016] Second, the present invention enables the lithium source and titanium source to undergo a solid-phase reaction in a short time through the rapid heat input generated by the conductive heating element, forming an acid-exchangeable lithium titanate precursor.

[0017] Third, by adjusting the temperature, time, current, voltage, output power, or relative position between the conductive heating element and the precursor mixture in the Joule heat treatment, the present invention can regulate the formation state of the lithium titanate precursor and reduce the heat exposure time caused by the long heating and holding process of the traditional furnace.

[0018] Fourth, the present invention can obtain an HTO type lithium ion sieve adsorbent after acid exchange delithiation treatment, and the obtained adsorbent has the ability to selectively adsorb lithium ions.

[0019] Fifth, the method of the present invention has a short process and is suitable for the rapid preparation of HTO-type lithium ion sieve adsorbents;

[0020] Sixth, the HTO-type lithium ion sieve adsorbent obtained by this invention can be used for the selective adsorption and recovery of lithium ions in salt lake brine, seawater, geothermal water or lithium-containing wastewater. Attached Figure Description

[0021] Figure 1 The temperature curve of Joule thermal radiation in step one of Experiment 1;

[0022] Figure 2 The process flow diagram for Experiment 1;

[0023] Figure 3 XRD patterns of HTO-type lithium-ion sieve adsorbents prepared at different Joule heat treatment temperatures in Experiment 2;

[0024] Figure 4 For the LTO precursor, HTO adsorbent after acid exchange, and adsorbed Li in Experiment 3 + XRD, FTIR, and XPS spectra of the HTO-a sample;

[0025] Figure 5 The results of lithium-ion adsorption performance of HTO-type lithium-ion sieve adsorbent prepared by the Joule thermal radiation method in Experiment 4;

[0026] Figure 6 Figure 1 shows the lithium ion selectivity and anti-interference adsorption results of HTO-type lithium ion sieve adsorbent prepared by the Joule thermal radiation method in Experiment 5.

[0027] Figure 7 Figure 6 shows the cyclic adsorption-desorption performance of the HTO-type lithium-ion sieve adsorbent prepared by the Joule thermal radiation method in Experiment 6.

[0028] Figure 8 The images show the SEM images and elemental distribution maps of the HTO-type lithium-ion sieve adsorbent after 10 adsorption-desorption cycles in Experiment 7. Detailed Implementation

[0029] Specific Implementation Method 1: This implementation method is a rapid preparation method for lithium-ion sieve adsorbents based on the Joule thermal radiation effect, specifically carried out according to the following steps:

[0030] 1. Mix lithium source and titanium source to obtain precursor mixture; place precursor mixture in Joule thermal radiation heating area, and rapidly heat treat precursor mixture through Joule thermal radiation effect generated by conductive heating element to cause solid-phase reaction of lithium source and titanium source to form lithium titanate precursor.

[0031] 2. The lithium titanate precursor prepared in step 1 is added to an acid solution for acid exchange delithiation treatment, so that some of the lithium ions in the lithium titanate precursor are replaced by hydrogen ions; after the acid exchange is completed, solid-liquid separation, washing and drying are performed in sequence to obtain HTO type lithium ion sieve adsorbent.

[0032] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the lithium source mentioned in step one is lithium carbonate, and the titanium source is anatase titanium dioxide. Everything else is the same as in Specific Implementation Method One.

[0033] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 2 in that the molar ratio of lithium in the lithium source to titanium in the titanium source in step one is (1.6~2.5):1. Everything else is the same as in Specific Implementation Method 2.

[0034] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the method of mixing the lithium source and titanium source in step one is grinding, ball milling, or stirring. Everything else is the same as in Specific Implementation Methods One to Three.

[0035] Specific Implementation Method Five: This implementation method differs from Specific Implementation Method Four in that the conductive heating element mentioned in step one is carbon paper, carbon cloth, graphite paper, graphite felt, graphite boat, graphite sheet, metal resistance sheet, or conductive ceramic carrier. Everything else is the same as in Specific Implementation Method Four.

[0036] Specific Implementation Method Six: This implementation method differs from Specific Implementation Method Five in that the precursor mixture described in step one is spread, pressed, filled, coated, or loaded onto the Joule heating region formed by the conductive heating element, and a distance of 2cm to 4cm is maintained between the conductive heating element and the precursor mixture. Everything else is the same as in Specific Implementation Method Five.

[0037] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Method Six in that the temperature of the Joule thermal radiation in step one is 500℃~950℃, and the processing time is 30s~10min. Everything else is the same as in Specific Implementation Method Six.

[0038] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Method Seven in that the acid solution mentioned in step two is hydrochloric acid with a concentration of 0.01 mol / L to 0.5 mol / L. Everything else is the same as in Specific Implementation Method Seven.

[0039] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Method Eight in that the acid exchange time in step two is 0.5 h to 48 h. Everything else is the same as in Specific Implementation Method Eight.

[0040] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Method Nine in that: in step two, solid-liquid separation is performed by filtration, centrifugation, or sedimentation, and the resulting solid portion is washed until neutral, then dried at 60°C to obtain the HTO-type lithium-ion sieve adsorbent. Everything else is the same as in Specific Implementation Method Nine.

[0041] The invention was verified using the following experiments:

[0042] Experiment 1: This experiment demonstrates a method for the rapid preparation of lithium-ion sieve adsorbents based on the Joule thermal radiation effect. The specific steps are as follows:

[0043] 1. Grind and mix the lithium source and titanium source to obtain a precursor mixture; evenly spread the precursor mixture in the Joule heating region formed by the conductive heating element, with the precursor mixture directly below the conductive heating element and maintaining a distance of 3 cm between them. Electrodes are connected to both ends of the conductive heating element. After energizing, the Joule heating effect generated by the conductive heating element rapidly heats the precursor mixture, causing a solid-phase reaction between the lithium source and titanium source to form a lithium titanate precursor; the Joule heating temperature is 650℃, and the treatment time is 5 minutes (temperature control program as follows). Figure 1 (As shown in the figure) After the treatment was completed, the current input was stopped and the sample was cooled to room temperature to obtain the lithium titanate precursor;

[0044] The lithium source is lithium carbonate, the titanium source is anatase titanium dioxide, and the molar ratio of lithium in lithium carbonate to titanium in titanium dioxide is 2:1.

[0045] The conductive heating element is carbon paper;

[0046] 2. The lithium titanate precursor prepared in step one was added to a 0.25 mol / L hydrochloric acid solution for acid exchange delithiation. The acid exchange was allowed to proceed at room temperature for 24 hours, allowing at least a partial replacement of lithium ions in the lithium titanate precursor with hydrogen ions. After the acid exchange was completed, the mixture was filtered, and the resulting solid was washed until neutral. It was then dried at 60°C to obtain a product containing Li... + / H + HTO-type lithium-ion sieve adsorbent with exchange sites, process flow is as follows: Figure 2 .

[0047] Experiment 2: Effect of Joule heat treatment temperature on the structure of HTO type lithium ion sieve

[0048] The Joule heat treatment temperature affects both the degree of lithium titanate precursor formation and the ease of subsequent acid exchange delithiation. At excessively low temperatures, the solid-state reaction between the lithium and titanium sources is insufficient, making it difficult to form a structurally complete lithium titanate precursor, thus limiting the effective Lithium content that can be generated after acid exchange. + / H + There are relatively few exchange sites; at excessively high temperatures, the lithium titanate lattice tends to become denser and more stable, and the Li in the lattice... + It is difficult to remove completely, and lithium titanate-related phases may still remain after acid exchange. The appropriate Joule heat treatment temperature needs to balance the sufficient formation of the precursor and the feasibility of subsequent acid exchange.

[0049] The specific experiment differs from Experiment 1 in that the Joule heat radiation temperature is used in step one; otherwise, it is the same as Experiment 1. Finally, the corresponding HTO-X sample is prepared, where X represents the Joule heat treatment temperature. The resulting HTO-X sample is then subjected to X-ray diffraction analysis.

[0050] Depend on Figure 3 It can be seen that the samples obtained at lower temperatures still mainly consist of TiO2-related phases, indicating that the reaction between the lithium and titanium sources is insufficient, making it difficult to form a structurally complete titanium-based lithium-ion sieve. As the Joule heat treatment temperature increases, the samples after acid exchange gradually exhibit the phase characteristics of an HTO-type lithium-ion sieve, with the sample obtained at 650℃ (i.e., Experiment 1) showing a more suitable structural state. When the Joule heat treatment temperature continues to rise to 800℃ and 950℃, the related diffraction characteristics of Li2TiO3 (LTO) can still be observed in the samples after acid exchange, indicating that excessively high temperatures will increase the concentration of Li in the lattice. + The stability of the material limits acid exchange delithiation.

[0051] This experiment demonstrates that the Joule heat treatment temperature not only affects the formation of the lithium titanate precursor, but also influences the Li-P process during subsequent acid exchange. + Ejection and H + The formation of exchange sites. The Joule heat treatment temperature of 650℃ can achieve a good balance between precursor formation and acid exchange activation, so that the HTO type lithium ion sieve obtained after acid exchange has a more suitable structural state.

[0052] Experiment 3: Structural Changes of Samples Before and After Acid Exchange and Lithium Ion Adsorption

[0053] To verify that the lithium titanate precursor obtained by Joule heat treatment can be converted into an HTO-type lithium-ion sieve adsorbent via acid exchange, and to explain the Li content of the obtained adsorbent... + / H + The exchange process was carried out on the lithium titanate (LTO) precursor obtained by Joule heat treatment, the HTO adsorbent obtained after acid exchange, and the adsorbed Li... + The HTO-a samples were then analyzed by X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy.

[0054] Figure 4 a is XRD, from Figure 4 As can be seen from a, the LTO precursor exhibits the relevant diffraction characteristics of Li₂TiO₃; after acid exchange, it partially interacts with the lattice Li. + The related diffraction peaks weakened or changed, indicating that Li + It desorbs and forms an HTO-type structure. Li adsorbs... + The overall diffraction characteristics of the HTO-a sample were similar to those of HTO, and no obvious new crystal phases were observed, indicating that lithium ion adsorption mainly occurred within the original titanium-oxygen framework, rather than forming a new precipitate phase.

[0055] Figure 4 b is the FTIR plot, from Figure 4As shown in b, the OH and HOH-related vibrational signals of the sample increased after acid exchange, while the Li-O-related signal decreased, indicating that the acid exchange process caused partial lattice Li... + H + Displacement and formation of protonation exchange sites; adsorption of Li + Subsequently, the OH-related signal weakened, while the Li-O-related signal strengthened again, further indicating that the lithium-ion adsorption process involves Li. + / H + exchange.

[0056] Figure 4 c is the XPS graph, from Figure 4 As shown in c, the Li-O, H₂O, and Ti-O related components in the O1s spectrum undergo regular changes during acid exchange and lithium-ion adsorption, while the Ti-O framework-related signals remain stable. This indicates that the material undergoes reversible Li₂O₃ adsorption. + / H + Lithium ion adsorption is achieved through exchange, and the main structure of titanium oxide is not significantly damaged.

[0057] Experiment 4: Lithium-ion adsorption performance of HTO-type lithium-ion sieve adsorbent prepared by Joule thermal radiation method

[0058] The HTO-type lithium-ion sieve adsorbents prepared in Experiments 1 and 2 were added to a lithium-ion-containing solution (the solution contained only lithium as the metal cation). Adsorption experiments were conducted under set pH, temperature, and adsorption time conditions. During the adsorption process, samples were taken at different times to measure the change in lithium-ion concentration in the solution and to calculate the adsorption capacity.

[0059] Figure 5 Figure a shows the adsorption kinetics of samples obtained at different Joule heat treatment temperatures, with an initial lithium ion concentration of 300 mg / L. The results indicate that the HTO-type lithium ion sieve adsorbent prepared by the Joule thermal radiation method can adsorb lithium ions in solution, increasing rapidly in the initial stage and then gradually reaching equilibrium. HTO samples obtained at different Joule heat treatment temperatures all exhibited certain lithium ion adsorption capacity. HTO-650 (prepared in Experiment 1) obtained at 650℃ showed a higher adsorption capacity throughout the adsorption process; the sample obtained at 500℃ had a lower adsorption capacity, and further increases to 800℃ and 950℃ did not further improve the adsorption capacity. These results suggest that the Joule heat treatment condition at 650℃ can effectively balance the formation of lithium titanate precursors and the activation of acid exchange sites, thereby obtaining a larger amount of usable Lithium ions. + / H + Exchange site.

[0060] Figure 5b shows the isothermal adsorption results at different adsorption temperatures. Isothermal adsorption experiments were conducted under different initial lithium ion concentrations, and the equilibrium adsorption capacity was calculated based on the change in lithium ion concentration before and after adsorption. Figure 5 As shown in Figure b, the horizontal axis represents the initial lithium ion concentration in the solution. The lithium ion adsorption capacity of HTO-650 increases rapidly with increasing equilibrium lithium ion concentration and gradually approaches a plateau, indicating that the available exchange sites gradually approach saturation. The adsorption capacity increases significantly when the adsorption temperature increases from 20℃ to 30℃, but the increase is smaller when the temperature continues to rise to 40℃.

[0061] 5c represents the fitting result of the isothermal adsorption model, such as... Figure 5 As shown in c, the Langmuir model fits the isothermal adsorption data better than the Freundlich model, indicating that lithium-ion adsorption in HTO-650 mainly occurs in a limited and relatively homogeneous amount of Li. + / H + At the exchange site.

[0062] Experiment 5: Ion selectivity of HTO-type lithium-ion sieve adsorbent prepared by Joule thermal radiation method

[0063] To verify the lithium-ion selectivity of the obtained HTO-type lithium-ion sieve adsorbent in complex ionic systems, the adsorbent obtained in Experiment 1 was added to a mixed solution containing lithium ions, sodium ions, potassium ions, and magnesium ions, as well as a mixed solution containing anionic organic matter, for adsorption experiments. After adsorption, the concentration changes of each ion in the solution were measured, and the adsorption capacity or partition coefficient of different ions was calculated.

[0064] Test results show that the HTO-type lithium-ion sieve adsorbent prepared by the Joule thermal radiation method has a significant preferential adsorption capacity for lithium ions in multi-ion coexistence systems. For example... Figure 6 As shown in a, in Li + Mg 2+ K + and Na + Under coexisting conditions, the adsorbent for Li + The adsorption efficiency and adsorption capacity of Mg are significantly higher than those of other competing ions, while the adsorption capacity of Mg is higher than that of other competing ions. 2+ K + and Na + The low adsorption efficiency indicates that it has selective lithium-ion recognition capability. For example... Figure 6 As shown in b, in SO4 2- Cl - NO3 - Even when substances such as glucose, humic acid, and L-histidine coexist, the adsorbent can still maintain a high lithium-ion adsorption capacity, indicating that the adsorbent has a certain tolerance to interference from common anions and organic matter. Figure 6 a and Figure 6b represents two independent trials. Figure 6 The only metal cation in b is lithium ion.

[0065] This experiment demonstrates that the HTO-type lithium ion sieve adsorbent obtained after acid exchange of the lithium titanate precursor formed by Joule thermal radiation heating can still retain the selective adsorption characteristics of lithium ions and maintain good lithium ion adsorption capacity under the conditions of multiple ions and common coexisting substances. It can be used for the selective adsorption and recovery of lithium ions in complex systems such as salt lake brine, seawater, geothermal water or lithium-containing wastewater.

[0066] Experiment 6: Cyclic adsorption-desorption performance of HTO-type lithium-ion sieve adsorbent prepared by Joule thermal radiation method

[0067] To verify the recyclability of the obtained adsorbent, the HTO-type lithium-ion sieve adsorbent obtained in Experiment 1 was subjected to multiple adsorption-desorption cycle experiments. After each adsorption, the adsorbent was desorbed and regenerated using 0.2 mM hydrochloric acid, then washed until neutral before entering the next adsorption cycle.

[0068] Test results show that after 12 adsorption-desorption cycles, the HTO-type lithium-ion sieve adsorbent prepared by the Joule thermal radiation method still maintains a high lithium-ion adsorption capacity. Figure 7 As shown, the adsorption capacity decreased somewhat with increasing cycle number, but remained at a high level overall. This indicates that even after changing the precursor formation stage to Joule thermal radiation heating, the resulting adsorbent still possesses the potential for repeated adsorption-desorption. The results of the cyclic adsorption-desorption performance are shown below. Figure 7 .

[0069] This experiment demonstrates that the HTO-type lithium ion sieve adsorbent obtained in this invention can not only adsorb lithium ions, but also maintain a certain adsorption capacity after multiple adsorption-desorption cycles, and has the potential for repeated use.

[0070] Experiment 7: Morphology and elemental distribution stability of HTO type lithium-ion sieve adsorbent

[0071] To further verify the structural stability of the HTO-type lithium-ion sieve adsorbent prepared by the Joule thermal radiation method during the adsorption-desorption process, the adsorbent sample after 10 adsorption-desorption cycles in Experiment 6 was observed by scanning electron microscopy and analyzed by energy dispersive X-ray spectroscopy.

[0072] Depend on Figure 8It can be seen that after 10 adsorption-desorption cycles, the HTO-type lithium-ion sieve adsorbent still maintains the microstructure formed by the aggregation of fine particles, and no obvious large-area cracking, structural collapse or severe particle breakage was observed. Ti and O elements are relatively uniformly distributed in the sample area, and no obvious elemental segregation or local deficiency was observed, indicating that the titanium-oxygen main structure of the adsorbent still maintains good spatial distribution stability after cycling.

[0073] Furthermore, the overall Cl signal in the sample was weak, and no obvious local enrichment was observed, indicating that desorption and regeneration with hydrochloric acid did not result in significant local chlorine residue. These results demonstrate that the HTO-type lithium-ion sieve adsorbent prepared by the Joule thermal radiation method can maintain relatively stable particle morphology and Ti and O element distribution during multiple adsorption-desorption processes, exhibiting good cyclic stability.

Claims

1. A method for rapidly preparing lithium-ion sieve adsorbents based on the Joule thermal radiation effect, characterized in that... The method is performed according to the following steps:

1. Mix lithium source and titanium source to obtain precursor mixture; place precursor mixture in Joule thermal radiation heating area, and rapidly heat treat precursor mixture through Joule thermal radiation effect generated by conductive heating element to cause solid-phase reaction of lithium source and titanium source to form lithium titanate precursor.

2. The lithium titanate precursor prepared in step 1 is added to an acid solution for acid exchange delithiation treatment, so that some of the lithium ions in the lithium titanate precursor are replaced by hydrogen ions; after the acid exchange is completed, solid-liquid separation, washing and drying are performed in sequence to obtain HTO type lithium ion sieve adsorbent.

2. The method for rapidly preparing lithium-ion sieve adsorbents based on the Joule thermal radiation effect according to claim 1, characterized in that... The lithium source mentioned in step one is lithium carbonate, and the titanium source is anatase titanium dioxide.

3. The method for rapidly preparing lithium-ion sieve adsorbents based on the Joule thermal radiation effect according to claim 2, characterized in that... The molar ratio of lithium in the lithium source to titanium in the titanium source mentioned in step one is (1.6~2.5):

1.

4. The method for rapidly preparing lithium-ion sieve adsorbents based on the Joule thermal radiation effect according to claim 1, characterized in that... The method for mixing the lithium source and titanium source in step one is grinding, ball milling, or stirring.

5. The method for rapidly preparing lithium-ion sieve adsorbents based on the Joule thermal radiation effect according to claim 1, characterized in that... The conductive heating element mentioned in step one is carbon paper, carbon cloth, graphite paper, graphite felt, graphite boat, graphite sheet, metal resistor sheet, or conductive ceramic carrier.

6. The method for rapidly preparing lithium-ion sieve adsorbents based on the Joule thermal radiation effect according to claim 5, characterized in that... The precursor mixture described in step one is spread, pressed, filled, coated or loaded onto the Joule heating region formed by the conductive heating element, and a distance of 2cm to 4cm is maintained between the conductive heating element and the precursor mixture.

7. The method for rapidly preparing lithium-ion sieve adsorbents based on the Joule thermal radiation effect according to claim 1, characterized in that... The Joule thermal radiation temperature mentioned in step one is 500℃~950℃, and the processing time is 30s~10min.

8. The method for rapidly preparing lithium-ion sieve adsorbents based on the Joule thermal radiation effect according to claim 1, characterized in that... The acid solution mentioned in step two is hydrochloric acid with a concentration of 0.01 mol / L to 0.5 mol / L.

9. The method for rapidly preparing lithium-ion sieve adsorbents based on the Joule thermal radiation effect according to claim 8, characterized in that... The acid exchange time mentioned in step two is 0.5h to 48h.

10. The method for rapidly preparing lithium-ion sieve adsorbents based on the Joule thermal radiation effect according to claim 1, characterized in that... In step two, solid-liquid separation is carried out by filtration, centrifugation or sedimentation, and the obtained solid part is washed until neutral and then dried at 60°C to obtain HTO type lithium ion sieve adsorbent.

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