Preparation process of titanium composite adsorption resin for extracting lithium from salt lake

Abstract

The invention relates to the technical field of composite adsorption material preparation, and discloses a salt lake lithium extraction titanium system composite adsorption resin preparation technology, which comprises: placing a macroporous organic resin matrix loaded with a titanium lithium source and maintaining a solvent saturation state in a closed reaction kettle, and carrying out a reaction under an inert gas and initial pressure atmosphere, according to the preparation method disclosed by the invention, the problem that a traditional powdery ion sieve is easy to break and lose is solved by utilizing the anti-wear characteristic of an organic resin framework; and meanwhile, an in-situ composite interface realized by the process inhibits pulverization attenuation of active components in circulation, and ensures long service life and structural integrity of the material.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation process of a lithium-titanium composite adsorption resin for salt lake lithium extraction, and belongs to the technical field of composite adsorption material preparation. BACKGROUND

[0002] Currently, the selective removal or enrichment of specific target ions in a fluid is a core technical link for resource recovery and pollution control. At present, high selectivity adsorption mainly depends on inorganic ion sieve materials with specific crystal structures or surface functional groups, such as various titanium-based materials, which can exhibit high affinity for specific ions through ion exchange or lattice occupation. However, such high-selectivity inorganic materials face a common physical constraint in engineering applications. They usually exist in the form of micron or nanometer powders. These powders are prone to agglomeration and sedimentation or loss with the fluid in continuous flow industrial media. Their mechanical strength is also insufficient to withstand long-term physical erosion and particle abrasion in the adsorption column, leading to complex separation and recovery processes, high material loss rate, and difficulties in continuous and stable industrial operation. In order to improve the adsorption performance of the powder titanium-based material itself, research in this field has also focused on improving its capacity and efficiency through improved sintering processes and other preparation methods. For example, a Chinese invention patent with the publication number CN119281285B discloses a salt lake lithium extraction titanium-based adsorption material and its preparation method. This scheme uses a three-stage magnetic field sintering process to treat the mixture of titanium source and lithium source. The purpose is to optimize the crystal structure and specific surface area of the material through specific magnetic field and temperature parameters, in order to improve the lithium adsorption capacity and desorption rate of the powder material itself. This approach still revolves around how to prepare high-performance inorganic powders. The final product is still in the form of micron or nanometer powders. This scheme does not solve the physical constraints of the aforementioned powder materials in industrial applications, such as insufficient mechanical strength, easy agglomeration and loss, difficult separation and recovery, and high material loss rate.

[0003] On the contrary, traditional macroporous organic polymer resins, such as styrene divinylbenzene copolymers, have good mechanical strength, chemical stability, and macroscopic particle morphology, and are the mainstream filler materials for industrial continuous adsorption columns. However, their adsorption mechanism is mainly physical adsorption or non-selective ion exchange. For ions with similar structures and same charges, such as lithium ions and magnesium ions in brine, there is a lack of effective discrimination ability, making it difficult to meet the needs of high-purity separation. In order to combine the advantages of both, the field has also attempted to mechanically blend or physically coat inorganic ion sieve powders with organic resins. The interfacial bonding force between the organic and inorganic phases of such composite materials is usually weak. The active inorganic components are easily detached from the resin matrix under the action of swelling and shrinking stress or fluid shear force in multiple adsorption and desorption cycles, leading to rapid capacity decay and not effectively solving the problem of active component loss.

[0004] Therefore, how to in-situ composite the high-selectivity titanium ion sieve active component into the resin pore by a new preparation process, under the premise of maintaining the high mechanical strength skeleton of the organic polymer resin, so as to obtain a new adsorption material with high selectivity, high strength and high cycle stability, has become a technical problem to be solved by the present application. SUMMARY

[0005] The present application provides a preparation process of lithium extraction titanium composite adsorption resin from salt lake, which mainly aims to solve the problems in the prior art that high-selectivity inorganic ion sieve is difficult to be applied in engineering due to lack of mechanical strength, high-strength organic resin lacks adsorption selectivity, and the interface stability of simple physical combination of the two is poor and the active component is easy to fall off.

[0006] To achieve the above-mentioned purpose, the present application provides a preparation process of lithium extraction titanium composite adsorption resin from salt lake, comprising the following steps: Step 101, providing a macroporous organic polymer resin matrix, the macroporous organic polymer resin matrix having a pore structure connected to each other; Step 102, using a precursor solution containing titanium source and lithium source for in-situ loading to introduce the titanium source and lithium source into the pore structure of the macroporous organic polymer resin matrix, and keeping the pore structure in a saturated state of the precursor solution; Step 103, placing the macroporous organic polymer resin matrix loaded with titanium source and lithium source in a saturated state of the precursor solution into a sealed reaction kettle; Step 104, filling the sealed reaction kettle with inert gas and applying an initial pressure, then performing a temperature rising program on the sealed reaction kettle, heating the macroporous organic polymer resin matrix to a crystallization temperature under the initial pressure and inert gas atmosphere, and performing a high-temperature in-situ crystallization treatment at the crystallization temperature, so that the titanium source and lithium source are in-situ converted into titanium ion sieve active component inside the pore structure, and finally obtaining a lithium extraction titanium composite adsorption resin from salt lake.

[0007] Preferably, in step 102, the precursor solution is an acidic precursor solution containing titanium source, lithium source and aluminum source; the in-situ loading includes mixing the macroporous organic polymer resin matrix with the acidic precursor solution, stirring the reaction at a preset reaction temperature, so that the titanium source, lithium source and aluminum source are in-situ hydrolyzed and loaded inside the pore structure.

[0008] Preferably, in step 102, keeping the pore structure in a saturated state of the precursor solution is achieved by controlling the solid-liquid mass ratio of the macroporous organic polymer resin matrix to the acidic precursor solution to be 1:3 to 1:5.

[0009] Preferably, in step 104, the initial pressure is 1 MPa to 5 MPa, the crystallization temperature is 450 to 550 ; the temperature rising procedure includes rising to the crystallization temperature at a temperature rising rate of 1 / min to 5 / min.

[0010] Preferably, in step 104, the inert gas is selected from one or any combination of nitrogen and argon.

[0011] Preferably, in step 101, the macroporous organic polymer resin matrix is a styrene-divinylbenzene copolymer resin; the specific surface area of the macroporous organic polymer resin matrix is to , and the average pore size is 10 nm to 50 nm.

[0012] Preferably, in step 102, the molar amount of the titanium source is , the molar amount of the lithium source is , and the molar amount of the aluminum source is ; The molar ratio of satisfies , and the molar ratio of satisfies . .

[0013] Preferably, in step 102, the pH value of the acidic precursor solution is 3 to 4; the preset reaction temperature is 50 to 70 .

[0014] Preferably, before step 101, it further includes step 100: in step 100, the macroporous organic polymer resin matrix is pretreated, the pretreatment includes: first, using an ethanol solution for immersion treatment, then using a sodium hydroxide solution for immersion treatment, and finally washing with water to neutral.

[0015] Preferably, the salt lake lithium extraction titanium composite adsorption resin obtained by the preparation process has the structural characteristics that the titanium ion sieve active component is anchored in the pore structure inside the macroporous organic polymer resin matrix in the form of crystal grains with a particle size of 50 nm to 200 nm.

[0016] Compared with the prior art, the present application has the following beneficial effects: 1. The present application provides an organic-inorganic composite adsorption material, which uses macroporous organic polymer resin with continuous network structure and mechanical toughness as a physical support framework, and simultaneously anchors the titanium-based ion sieve active component in the pores of the framework in an in-situ loading manner. This structural design utilizes the anti-wear properties of the organic resin framework, thereby solving the problem of easy breakage and high frequency loss of traditional powdered ion sieves due to inter-particle collision and shear in industrialized continuous fluid scouring, and making the high selectivity adsorption function compatible with the mechanical stability required for large-scale engineering applications.

[0017] 2. The material structure of the present application is not a simple superposition of the functions of the two components, but a synergistic ion sieve selection mechanism generated by the composite interface formed by the titanium-based ion sieve active sites and the pore wall surface of the macroporous resin matrix. This interface restructures the mass transfer barrier and affinity properties of different hydrated ions in brine, such as through confinement effect or charge repulsion, especially enhances the repulsion of divalent cations (such as magnesium ions), so that the selectivity coefficient for lithium ions exceeds the inherent level of a single titanium-based ion sieve component, achieving nonlinear improvement of adsorption performance.

[0018] 3. The composite interface formed by in-situ loading has a binding strength and stability that cannot be compared with simple physical and mechanical blending. More importantly, the flexible segment structure unique to the macroporous organic polymer matrix provides a buffer space for the microswelling or shrinking of the titanium-based ion sieve during adsorption and desorption cycles, inhibits the lattice pulverization and irreversible capacity decay of the active component caused by long-term cyclic stress, and ensures the long-term service life and structural integrity of the adsorption material under harsh working conditions. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The preparation process flow chart of the key process parameters of the present application; Figure 2 The performance comparison chart of the sample group and the control group in terms of adsorption capacity mechanical wear rate and cycle stability of the present application; Figure 3 The composite structure diagram of the macroporous resin matrix and the titanium-based active component of the present application; Figure 4 The interactive timing chart of each key step of the preparation process of the present application. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical scheme and advantages of the present application clearer and more apparent, the present application will be further described in detail below with reference to specific embodiments, and it should be noted that the specific embodiments herein are only used to explain the present application and do not limit the protection scope of the present application.

[0021] The application provides a preparation process of a salt lake lithium extraction titanium-based composite adsorption resin. The process anchors titanium-based ion sieve active components in the pore channels of a macroporous organic polymer resin matrix through high-temperature in-situ crystallization treatment. The prepared composite adsorption material has high selectivity, high mechanical strength and high cycle stability, and overcomes the problems of easy loss of traditional powder ion sieves, insufficient mechanical strength and non-selectivity of organic resins. The process includes the following main steps: providing and pretreating the matrix material, in-situ loading of a precursor solution, and high-temperature in-situ crystallization treatment under specific high pressure and inert atmosphere conditions. In a specific implementation path, the process can include a matrix pretreatment step, namely step 100. In this step, first, an ethanol solution is used to soak the macroporous organic polymer resin matrix to swell the resin skeleton and remove residual organic impurities or pore-forming agents in the pore channels. Then, a sodium hydroxide solution is used for soaking treatment to hydrolyze or activate the functional groups on the surface of the resin, thereby enhancing the hydrophilicity and combination with the subsequent precursor. Finally, water is used for washing to neutralize the solution, remove residual alkali and impurities, and obtain a clean and wet resin matrix for subsequent loading in step 102. In step 101, the provided macroporous organic polymer resin matrix plays an important role in the mechanical properties and loading properties of the final composite material. The macroporous organic polymer resin matrix is a styrene-divinylbenzene copolymer resin. This type of resin has a mature industrial production basis and excellent physical wear resistance and chemical stability. Further, to achieve efficient loading and firm anchoring, the physical structure parameters of the macroporous organic polymer resin matrix are limited. The specific surface area of the macroporous organic polymer resin matrix is preferably 500-2000 m2 / g. When the specific surface area is less than 500 m2 / g, the active sites available for precursor loading are insufficient, resulting in a low loading rate of active components. When the specific surface area is greater than 2000 m2 / g, it usually means that the pore wall of the resin skeleton is too thin, the mechanical strength is reduced, and the macroporous organic polymer resin matrix is easily damaged in long-term fluid scouring. The average pore diameter of the macroporous organic polymer resin matrix is preferably 10-50 nm. This pore diameter range ensures that the precursor solution can smoothly enter the pore channel network, and provides a physical confinement space for the titanium-based ion sieve active component grains generated in-situ subsequently (the grain size is usually 50-200 nm). The anchoring mechanism can be: the precursor nucleates and grows at the larger cavity nodes in the resin pore channel network. When the grain size grows to 50 nm or more, its size is larger than the 10-50 nm pore throat, and is thus physically anchored in the pore structure and cannot be detached with the fluid. This directly corresponds to the final structural characteristics of the salt lake lithium extraction titanium-based composite adsorption resin. to ; when the specific surface area is less than , the active sites available for precursor loading are insufficient, resulting in a low loading rate of active components. When the specific surface area is greater than , it usually means that the pore wall of the resin skeleton is too thin, the mechanical strength is reduced, and the macroporous organic polymer resin matrix is easily damaged in long-term fluid scouring. The average pore diameter of the macroporous organic polymer resin matrix is preferably 10-50 nm. This pore diameter range ensures that the precursor solution can smoothly enter the pore channel network, and provides a physical confinement space for the titanium-based ion sieve active component grains generated in-situ subsequently (the grain size is usually 50-200 nm). The anchoring mechanism can be: the precursor nucleates and grows at the larger cavity nodes in the resin pore channel network. When the grain size grows to 50 nm or more, its size is larger than the 10-50 nm pore throat, and is thus physically anchored in the pore structure and cannot be detached with the fluid. This directly corresponds to the final structural characteristics of the salt lake lithium extraction titanium-based composite adsorption resin.

[0022] In step 102, in-situ loading is performed, the core of which is to introduce the titanium source and lithium source into the pore structure of the macroporous organic polymer resin matrix, in a preferred embodiment, the step is achieved by using an acidic precursor solution containing titanium source, lithium source and aluminum source; the introduction of aluminum source plays a role in stabilizing the crystal structure of titanium-based ion sieve and improving its cycle stability, the specific operation of the in-situ loading includes: mixing the macroporous organic polymer resin matrix pretreated in step 100 with the acidic precursor solution, and stirring at a preset reaction temperature, in the process, by controlling the pH value of the acidic precursor solution to be preferably 3 to 4, and the preset reaction temperature to be preferably 50 to 70 , the hydrolysis-polycondensation rate of titanium source, lithium source and aluminum source inside the pore structure is regulated; if the pH value is lower than 3, the hydrolysis is too fast, and amorphous precipitate is easily formed outside the resin particles instead of being loaded in the pores; if the pH value is higher than 4, the hydrolysis is insufficient, and the loading amount is low; if the reaction temperature is lower than 50 , the reaction and diffusion rate is too slow, and the time is too long; if the temperature is higher than 70 , the solvent volatilizes too fast, and the precursors are easily polymerized at the pore mouth too early, blocking the pore; in order to ensure the reaction uniformity and efficiency of the subsequent high-temperature crystallization step, step 102 also emphasizes that the pore structure inside is kept saturated with the precursor solution. This is achieved by controlling a process parameter, that is, controlling the solid-liquid mass ratio of the macroporous organic polymer resin matrix and the acidic precursor solution to be 1:3 to 1:5; when the solid-liquid mass ratio is lower than 1:3, the total amount of the precursor solution is insufficient to completely fill the pores of the resin, resulting in a semi-dry state inside the pore, and the reactants are insufficient and the heat transfer is uneven during the subsequent high-temperature treatment; when the solid-liquid mass ratio is higher than 1:5, there is a large amount of free precursor solution between the resin particles, which will form useless powder-like ion sieve on the inner wall of the reaction kettle or the surface of the resin during the subsequent high-temperature treatment, reducing the raw material utilization rate and product purity. Keeping the pore inside saturated with the solvent is a prerequisite for the high-temperature in-situ crystallization in step 104, and these saturated solvents will be converted into reaction medium under subsequent high temperature and high pressure, promoting the transformation of the crystal phase.

[0023] The solid-liquid mass ratio of the macroporous organic polymer resin matrix and the acidic precursor solution in step 102 to is a specific example for the resin matrix with a specific surface area of and an average pore size of as described in example 2; when a person skilled in the art selects other resin matrices with different porosities or specific surface areas, in order to keep the pore structure inside saturated with the precursor solution, the corresponding solid-liquid mass ratio can be determined by the conventional liquid absorption test method in the art, which includes: obtaining the resin matrix pretreated in step 100 and dried to a constant weight, and counting the dry weight The dry resin matrix is ​​completely immersed in a precursor solution or a simulated solvent with similar pH and ionic strength and allowed to stand to fully fill the pores. Then, it is centrifuged. , Or gravity titration on a standard sieve (e.g.) Remove the free solution adhering between resin particles using the following method, and weigh the saturated resin matrix at this point. Thus through The calculated ratio is the target solid-liquid mass ratio required to achieve the saturation state of the specific resin matrix; this determination process is a conventional technique in this field. To achieve in-situ conversion of the titanium and lithium sources into titanium-based ion sieve active components within the porous structure, the molar ratio of each component in the precursor needs to be limited. Let the molar amount of the titanium source be... The molar amount of lithium source is The molar amount of aluminum source is Preferably, and The molar ratio satisfies ,and and The molar ratio satisfies ; The molar ratio affects the formation of the target lithium titanate phase. When it is below 1.5, the lithium source is insufficient, and an inactive phase or a phase with low lithium content is easily formed, resulting in low adsorption capacity. When it is above 1.7, excess lithium may exist in the form of lithium oxide, affecting the structural stability and acid resistance of the material. The molar ratio controls the amount of aluminum doping. When it is below 0.15, the stabilizing effect of aluminum on the crystal lattice is not obvious; when it is above 0.25, too many aluminum atoms enter the titanium lattice, which may lead to lattice distortion and destroy the selective adsorption channels for lithium ions.

[0024] Steps 103 and 104 together constitute a high-temperature in-situ crystallization treatment stage under a closed, high-pressure environment. In step 103, the macroporous organic polymer resin matrix, which is saturated with the precursor solution and loaded with titanium and lithium sources obtained in the previous steps, is rapidly transferred and placed in a closed reactor. Subsequently, in step 104, a series of precisely controlled procedures are performed on the closed reactor: first, an inert gas, preferably nitrogen, argon, or any combination thereof, is introduced into the closed reactor to purge oxygen and create an oxygen-free atmosphere, thereby preventing the macroporous organic polymer resin matrix (styrene-divinylbenzene copolymer) from crystallizing at temperatures as high as 450°C in subsequent processes. Up to 550 Oxidation, combustion, or carbonization degradation occur at high temperatures. Then, an initial pressure is applied to the sealed reactor, which has been filled with inert gas. The initial pressure is preferably controlled within the range of 1 MPa to 5 MPa. This initial pressure, in conjunction with the sealed reactor, inhibits premature boiling and vaporization of the saturated precursor solution within the resin channels during the heating process. When the pressure is below 1 MPa, a large amount of solvent is lost from the channels before reaching the crystallization temperature, failing to form a uniform high-temperature reaction environment, resulting in incomplete crystallization. When the pressure is above 5 MPa, the pressure resistance requirement for the equipment is too high, increasing costs, while the improvement in crystallization effect is not significant. Under the combined action of the initial pressure and the inert gas atmosphere, a heating program is executed on the sealed reactor. The heating program preferably includes a 1... / min to 5 The temperature is increased to the crystallization temperature at a heating rate of 5 / min; this heating rate is used as a kinetic control parameter. If the heating rate is faster than 5 If the heating rate is slower than 1 / min, the solvent inside the resin channels may vaporize instantaneously due to rapid heating, generating localized high pressure and causing physical cracking of the resin skeleton; If the process cycle is too long ( / min), it will be uneconomical and may cause the precursor to form a non-target, thermodynamically more stable impurity phase in the intermediate temperature range.

[0025] When the temperature of the reactor reaches the crystallization temperature (preferably 450°C) Up to 550 Afterwards, high-temperature in-situ crystallization treatment is carried out at this temperature; the selection of crystallization temperature takes into account both the phase transformation requirements of inorganic components and the thermal stability boundary of the organic matrix; the temperature is below 450°C. The activation energy is insufficient to overcome the transformation of precursor hydrolysis products into the active phase of highly crystalline titanium-based ion sieves, resulting in products that remain amorphous or have very low crystallinity, lacking adsorption selectivity; temperatures above 550°C... Even under inert gas protection, prolonged high temperatures can cause a certain degree of pyrolysis or carbonization of the styrene-divinylbenzene copolymer resin matrix, reducing its mechanical strength and flexibility. This is especially true under pressures of 1 MPa to 5 MPa, an inert atmosphere, and at 450°C. Up to 550 Under certain temperature conditions, the saturated aqueous solution within the resin channels transforms into a high-temperature, high-pressure solvothermal medium, promoting mass transfer and reaction of titanium, lithium, and aluminum precursors within the confined space of the channels. This allows them to be converted in situ into highly active titanium-based ion sieve components, while the framework structure of the organic resin matrix is ​​preserved, ultimately yielding a titanium-based composite adsorption resin for lithium extraction from salt lakes. The inner wall material of the sealed reactor used in step 104 should be selected to withstand temperatures up to 450°C. Up to 550 high temperature, to Materials that do not catalyze the pyrolysis reaction of styrene-divinylbenzene copolymer resin matrix in pressure and acidic solvothermal media, such as Hastelloy or specific grades of pressure-resistant stainless steel; in engineering implementation, to verify whether the selected reactor material meets this inertness requirement, a blank control experiment can be performed: the resin matrix, which has not been loaded in step 102 but has been pretreated in step 100 and kept in a solvent-saturated state, is placed in the reactor, and a high-temperature and high-pressure treatment is performed strictly according to the process conditions of step 104 (including inert gas filling, initial pressure application, heating rate, and crystallization temperature). After treatment, the blank resin matrix is ​​taken out, and its mechanical wear rate is tested according to the test method used in Table 1; if the measured mechanical wear rate is close to the value of control group 2 (drying-inert-atmospheric pressure pyrolysis) as shown in Table 1, the mechanical wear rate is considered to be high. If so, it indicates that the material of the reactor is not suitable.

[0026] Example 1: This example illustrates a specific application of the preparation process within a particular process route. The challenge lies in achieving the high temperature required to transform the titanium-based precursor into the active component of a highly crystalline titanium-based ion sieve, which in this example is 500°C. A balance must be struck between maintaining the integrity of the macroporous organic polymer resin matrix, namely the styrene-divinylbenzene copolymer skeletal structure; traditional preparation methods face a technical constraint here, especially when carried out in an air atmosphere at 500°C. High-temperature treatment will cause the organic resin matrix to oxidize and burn, thus failing; if conventional pyrolysis is performed under an inert atmosphere, the resin matrix will carbonize, losing its original mechanical flexibility and skeletal properties. Neither of these methods can obtain a composite material that has both an organic skeleton and inorganic activity.

[0027] The process path in this embodiment follows the control of maintaining the saturated state of the precursor solution inside the pore structure in step 102, and combines the synergistic effect of applying inert gas and initial pressure in the closed reactor in step 104. During the heating procedure in step 104, the saturated precursor solution inside the macroporous organic polymer resin matrix pores primarily uses water as its solvent, unlike in open systems where the temperature is not maintained at 100°C. Instead, under the constraint of an initial pressure (set to 3 MPa in this embodiment), the solvent confined within the pore network transforms into a high-temperature, high-pressure solvothermal reaction medium. This solvothermal environment, formed in situ within the pores, promotes the reaction of titanium, lithium, and aluminum precursors at 500°C. At the crystallization temperature, the active phase of the target titanium-based ion sieve is transformed in situ; at the same time, an inert gas, nitrogen in this embodiment, is introduced into the sealed reactor to form an inert atmosphere environment inside the reactor, which inhibits the oxidation or excessive pyrolysis of the skeleton of the macroporous organic polymer resin matrix at high temperature, thus maintaining its structural integrity; this process route ultimately yields a titanium-based composite adsorption resin for lithium extraction from salt lakes, in which the active titanium-based ion sieve component is in the form of highly crystalline grains, with a particle size of 80 nm to 150 nm measured in this embodiment, which is physically anchored inside the pore structure of the macroporous organic polymer resin matrix with an average pore size of 35 nm.

[0028] Example 2: This example uses a set of control experiments to verify the key process conditions in the preparation process of this invention, especially the inert gas atmosphere, initial pressure, and solvent saturation state in the pores during the high-temperature in-situ crystallization step, and their role in obtaining a titanium-based composite adsorption resin for lithium extraction from salt lakes that possesses both mechanical stability and high adsorption activity. The initial materials and reagent specifications used in the experiment were determined as follows: The macroporous organic polymer resin matrix was selected as styrene-divinylbenzene copolymer resin, with a specific surface area of ​​415 m² / g, an average pore size of 28 nm, and a particle size range of 0.4 mm to 0.8 mm; the acidic precursor solution was titanium tetrachloride (… Lithium acetate ) and aluminum nitrate ( The solution is prepared by dissolving titanium, lithium, and aluminum sources in deionized water, with the molar ratio adjusted to [value missing]. and The pH of the solution was adjusted to 3.5 using dilute hydrochloric acid. Four experimental sample groups were prepared, with the pretreatment in step 100 and the in-situ loading in step 102 being the same, i.e., the pretreated resin matrix was mixed with the acidic precursor solution at 60 °C. The reaction was stirred for 12 hours. The key differences between the sample groups lay in the post-loading treatment and the conditions of the high-temperature crystallization treatment (step 104): The sample group (experimental group) of this invention was processed according to the process of this invention. The resin matrix, after loading and maintaining the precursor solution saturation by controlling the solid-liquid mass ratio to 1:4, was placed in a sealed reaction vessel, filled with nitrogen (inert gas), and an initial pressure of 3.0 MPa was applied. Subsequently, the reaction was carried out at 3... Heating rate increased to 500°C / min (Crystallization temperature), and isothermal treatment for 4 hours. Control group 1 (high temperature-air atmosphere) simulates conventional air calcination, and the loaded resin matrix is ​​subjected to 80°C. Dry for 12 hours to constant weight, then place in a muffle furnace and heat in air at 300°C. Heating to 500 at a rate of / min The resin matrix was subjected to constant temperature treatment for 4 hours. Control group 2 (high temperature-inert atmosphere-normal pressure) simulated conventional inert atmosphere pyrolysis, and the loaded resin matrix was subjected to constant temperature treatment at 80°C. Dry for 12 hours to constant weight, then place in a tube furnace and heat at 300°C under a flowing nitrogen (inert gas) atmosphere (0.1 MPa, i.e., atmospheric pressure). Heating to 500 at a rate of / min The mixture was kept at a constant temperature for 4 hours. Control group 3 (physical blending) simulated the simple physical compounding in the existing technology. The acidic precursor solution was dried separately and placed in a muffle furnace at 500°C in an air atmosphere. Calcination for 4 hours yielded pure titanium-based ion sieve active component powder. Subsequently, this powder was mechanically blended with an untreated, pristine macroporous organic polymer resin matrix (i.e., the matrix provided in step 101) at a mass ratio of 1:4. The materials obtained after the above four treatments were tested for their key performance indicators according to the general standards for environmental remediation materials in this field, including: saturated adsorption capacity (in simulated salt lake brine, containing...). 200mg / L 20000mg / L, 25 After 24 hours of oscillation The adsorption capacity was calculated by ICP-OES detection of the difference, the mechanical wear rate (the particle breakage rate after 30 minutes under specified vibration conditions according to GB / T16598-1996 method), and the cycle stability (the saturated adsorption capacity was tested and the capacity retention rate was calculated after 50 adsorption-desorption cycles in the above brine). The test data are summarized in Table 1.

[0029] Table 1: Comparison of the effects of different preparation process conditions on the performance of composite adsorption resins The data analysis in Table 1 is as follows: The resin matrix of control group 1 was at 500... Complete oxidation and ashing under air atmosphere, with a mechanical wear rate of 100.0%, indicates complete material failure. This demonstrates that using an inert gas atmosphere in step 104 is necessary to prevent the macroporous organic polymer resin matrix from failing at high temperatures. Although control group 3 exhibits a high initial saturated adsorption capacity, its mechanical wear rate is as high as 22.5%, and its capacity retention rate after 50 cycles is only 35.7%, indicating that simple physical blending cannot form a stable organic-inorganic interface, and the active component powder is easily detached and lost from the resin matrix during fluid flushing and circulation. A comparison of data between control group 2 and the sample group of this invention shows that initial pressure and solvent saturation have a synergistic effect. Control group 2, treated under an inert atmosphere but at ambient pressure, showed that... The process is essentially conventional pyrolysis, resulting in a carbonized and brittle resin matrix, leading to a mechanical wear rate as high as 14.6% and poor cycle stability. In contrast, the sample group of this invention, through high-temperature in-situ crystallization treatment of the solvent-saturated matrix under an initial pressure of 3.0 MPa (as in Example 1), inhibited resin carbonization and promoted solvothermal crystallization within the pores, ultimately obtaining a material with a mechanical wear rate of only 0.9% and a capacity retention rate of 92.4% after 50 cycles. Experimental data show that the macroporous organic polymer resin matrix, solvent saturation, closed reaction vessel, inert gas and initial pressure, and crystallization temperature in the preparation process work together to ensure the production of a composite adsorption resin with high mechanical strength and high cycle stability.

[0030] Example 3: In this example, a comparative sample group was prepared. This sample group was prepared by physical blending and was used to compare the in-situ crystallization process of the present invention. The macroporous organic polymer resin matrix used was the same as the matrix used in Example 2. First, titanium-based ion sieve active component powder was prepared. The process was as follows: the acidic precursor solution from Example 2 was taken and heated in a 100°C solution. Dry in an oven for 12 hours to obtain dry material; place the dry material in a muffle furnace and heat in an air atmosphere at 5°C. Heat up to 500 / min The mixture was treated at a constant temperature for 4 hours, then naturally cooled and ground. It was then passed through a 200-mesh sieve to obtain pure titanium-based ion sieve active component powder. Subsequently, 100 grams of the above-prepared titanium-based ion sieve active component powder was mixed with 400 grams of [unclear - possibly a specific type of powder] sieve filtered at 80 [unclear - possibly a specific temperature]. A macroporous organic polymer resin matrix dried for 4 hours was placed in a V-type mixer and mechanically blended at 30 rpm for 2 hours to obtain a comparative sample group. The mechanical wear rate and cycle stability of the comparative sample group were tested using the same test method as in Example 2. The measured mechanical wear rate was 22.5%. After 50 adsorption-desorption cycles, its saturated adsorption capacity decreased, and the capacity retention rate was only 35.7%. The test data of this comparative sample group show that the composite material prepared by physical blending has insufficient interfacial bonding stability between organic and inorganic components. The active component powder is easily detached and lost under mechanical vibration and circulating fluid scouring, failing to effectively solve the problems of high material loss rate and poor cycle stability in the prior art.

[0031] Example 4: This example combines Figures 1 to 4 The preparation process of a titanium-based composite adsorption resin for lithium extraction from salt lakes is described, as follows: Figure 1 As shown, the process begins with step 100, matrix pretreatment, which includes soaking in an ethanol solution, soaking in a sodium hydroxide solution, and washing with water until neutral. Then, step 101 provides the matrix, i.e., a macroporous organic polymer resin matrix, such as a styrene-divinylbenzene copolymer. Preferred matrix physical parameters are defined, including a specific surface area of ​​300-500. Average pore size: 10-50 nm. Next, step 102 involves in-situ loading of the precursor using an acidic precursor solution containing titanium, lithium, and aluminum sources. The reaction is stirred to maintain saturation within the pores. The loading process control conditions are defined as follows: solid-liquid mass ratio: 1:3 to 1:5; pH of the acidic precursor: 3 to 4; preset reaction temperature: 50-70 °C. Next, step 103 involves placing the saturated resin matrix into a sealed reactor. Finally, step 104, high-temperature in-situ crystallization treatment, is performed by introducing inert gas and applying initial pressure, followed by a heating program to the crystallization temperature, allowing the active components to transform in situ within the pores. The core crystallization conditions for this step include an inert gas atmosphere. , Initial pressure 1-5 MPa, crystallization temperature 450-550 °C and heating rate 1-5 / min, finally obtaining the titanium-based composite adsorption resin for lithium extraction from salt lakes.

[0032] like Figure 2 As shown in the chart, the left ordinate is the saturated adsorption capacity (mg / g) and the right ordinate is the mechanical wear rate (%). The chart uses a bar chart to represent the saturated adsorption capacity (mg / g), a dashed line with hollow circles to represent the mechanical wear rate (%), and a dotted line with solid dots to represent the capacity retention rate after 50 cycles. This clearly demonstrates the comprehensive performance advantages of the present invention's sample group in these three indicators.Figure 3 As shown in the figure, the structure of the excellent performance is derived from the fact that the composite adsorption resin is composed of component 1: macroporous organic polymer resin matrix and component 2: titanium-based ion sieve active component. The main function of component 1 is to provide the pore structure, while the characteristic of component 2 is that it is anchored in the form of crystal grains.

[0033] like Figure 4 As shown, the operator performs step 100 pretreatment and step 101 to provide a matrix specific surface area of ​​300-500 nm on the resin matrix. The resin matrix has an average pore size of 10-50 nm. A precursor solution containing titanium, lithium, and aluminum sources is prepared. In step 102, the operator mixes and stirs the resin matrix and precursor solution in situ to allow the precursor solution to penetrate the pores and maintain saturation. In step 103, the operator loads the loaded matrix into a sealed reactor, and in step 104, inert gas is introduced and pressurized. The temperature inside the sealed reactor is then raised to the crystallization temperature of 450-550 °C. High-temperature in-situ crystallization treatment ultimately yields a product with high selectivity, high strength, and high stability, namely, a titanium-based composite adsorption resin for lithium extraction from salt lakes.

[0034] Example 5: This example provides a standardized engineering calibration procedure for determining the key process parameter, i.e., the crystallization temperature, in the high-temperature in-situ crystallization treatment step (step 104), to solve the technical trade-off between ensuring sufficient crystallization of the active component of the titanium-based ion sieve (corresponding to high saturation adsorption capacity) and avoiding thermal damage to the macroporous organic polymer resin matrix (corresponding to low mechanical wear rate); five test sample groups were prepared, labeled as sample group 4-1 to sample group 4-5; all sample groups used the same initial materials, reagent specifications, step 100 pretreatment process, and step 102 in-situ loading process as the sample groups of the present invention in Example 2, and ensured that they were all in a precursor solution saturated state after loading (solid-liquid mass ratio 1:4); the above five sample groups were placed in a closed reaction vessel, and the process conditions of step 104 were performed, i.e., nitrogen was introduced, an initial pressure of 3.0 MPa was applied, and the temperature was 3 The heating rate is 1 / min; the only process variable is the set isothermal crystallization temperature, which is 425°C. (Sample group 4-1), 450 (Sample group 4-2), 500 (Sample group 4-3), 550 (Sample group 4-4) and 575 (Samples 4-5) The constant temperature treatment time was set to 4 hours. After the five test sample groups were cooled and post-treated, their saturated adsorption capacity and mechanical wear rate were tested using the same test standards as in Example 2. The test results are recorded in Table 2.

[0035] Table 2: Effects of Different Crystallization Temperatures on Key Properties of Composite Adsorption Resins The data in Table 2 show that when the crystallization temperature is 425°C... At this temperature (sample group 4-1), although the mechanical wear rate was very low, the saturated adsorption capacity was only 72.4 mg / g, indicating that this temperature was lower than the activation energy required for the precursor to transform into a highly active crystalline phase, resulting in insufficient crystallization; when the crystallization temperature was 450... Up to 550 Within the specified range (sample groups 4-2, 4-3, and 4-4), the materials all exhibited a combination of high saturated adsorption capacity (all greater than 115 mg / g) and low mechanical wear rate (all less than 1.5%); however, when the crystallization temperature was increased to 575... At that time (sample group 4-5), the mechanical wear rate of the material increased to 5.5%, and the saturated adsorption capacity also decreased to 98.6 mg / g. This indicates that the excessively high temperature has caused thermal damage to the skeleton structure of the macroporous organic polymer resin matrix, resulting in a decrease in mechanical strength and the possible failure of some active sites due to structural damage.

[0036] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A preparation process of a lithium and titanium composite adsorption resin for extracting lithium from salt lakes, characterized in that, The method comprises the following steps: Step 101, providing a macroporous organic polymer resin matrix having a pore structure connected to each other; Step 102, in-situ loading by using a precursor solution containing a titanium source and a lithium source to introduce the titanium source and the lithium source into the pore structure of the macroporous organic polymer resin matrix and keep the pore structure saturated with the precursor solution; Step 103, placing the macroporous organic polymer resin matrix loaded with the titanium source and the lithium source in a saturated state of the precursor solution into a sealed reaction kettle; Step 104, filling the sealed reaction kettle with an inert gas and applying an initial pressure, and then performing a temperature rising program on the sealed reaction kettle, heating the macroporous organic polymer resin matrix to a crystallization temperature under the initial pressure and the inert gas atmosphere, and performing a high-temperature in-situ crystallization treatment at the crystallization temperature, so that the titanium source and the lithium source are in-situ converted into a titanium-based ion sieve active component inside the pore structure, and finally a lithium extraction titanium-based composite adsorption resin for salt lake is obtained.

2. The preparation process of the lithium and titanium composite adsorption resin for extracting lithium from salt lake according to claim 1, characterized in that, In step 102, the precursor solution is an acidic precursor solution containing a titanium source, a lithium source and an aluminum source; the in-situ loading includes mixing the macroporous organic polymer resin matrix with the acidic precursor solution, stirring the reaction at a preset reaction temperature, so that the titanium source, the lithium source and the aluminum source are in-situ hydrolyzed and loaded inside the pore structure.

3. The preparation process of the lithium and titanium composite adsorption resin for extracting lithium from salt lake according to claim 2, characterized in that, In step 102, the saturation of the pore structure with the precursor solution is achieved by controlling the solid-liquid mass ratio of the macroporous organic polymer resin matrix to the acidic precursor solution to be 1:3 to 1:

5.

4. The preparation process of the lithium and titanium composite adsorption resin for extracting lithium from salt lake according to claim 1, characterized in that, In step 104, the initial pressure is 1 MPa to 5 MPa, and the crystallization temperature is 450 to 550 °C. The temperature rising procedure includes temperature rising to the crystallization temperature at a temperature rising rate of 1 to 5 min / min.

5. The preparation process of the lithium and titanium composite adsorption resin for extracting lithium from salt lake according to claim 1, characterized in that, In step 104, the inert gas is selected from one or any combination of nitrogen and argon.

6. The preparation process of the lithium and titanium composite adsorption resin for extracting lithium from salt lake according to claim 1, characterized in that, In step 101, the macroporous organic polymer resin matrix is a styrene-divinylbenzene copolymer resin; the specific surface area of the macroporous organic polymer resin matrix is 50-500 m2 / g to , and the average pore size is 10-50 nm.

7. The preparation process of the lithium and titanium composite adsorption resin for extracting lithium from salt lake according to claim 2, characterized in that, In step 102, the molar amount of the titanium source is , the molar amount of the lithium source is , and the molar amount of the aluminum source is ; The molar ratio of satisfies , and the molar ratio of and satisfies .

8. The preparation process of the lithium and titanium composite adsorption resin for extracting lithium from salt lake according to claim 2, characterized in that, In step 102, the pH value of the acidic precursor solution is 3 to 4; the preset reaction temperature is 50 to 70 .

9. The preparation process of the lithium and titanium composite adsorption resin for extracting lithium from salt lake according to claim 1, characterized in that, Before step 101, step 100 is further included: step 100, pretreating the macroporous organic polymer resin matrix, which includes first soaking with an ethanol solution, then soaking with a sodium hydroxide solution, and finally washing with water to neutral.

10. The preparation process of the lithium and titanium composite adsorption resin for extracting lithium from salt lake according to claim 1, characterized in that, The lithium extraction titanium-based composite adsorption resin for salt lake obtained by the preparation process has the following structural characteristics: The titanium-based ion sieve active component is anchored inside the pore structure of the macroporous organic polymer resin matrix in the form of crystal grains with a particle size of 50 nm to 200 nm.

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