Preparation method for titanium-based lithium ion sieve, product prepared thereby, and use

Abstract

The present application relates to the technical field of lithium ion adsorption, and provides a preparation method for a titanium-based lithium ion sieve, a product prepared thereby, and a use. The preparation method for a titanium-based lithium ion sieve comprises the following steps: mixing a water-soluble lithium source, a titanium source, and a tackifier, and sequentially carrying out ball milling and sanding to obtain a mixture slurry of the lithium source and the titanium source; drying the mixed slurry and then carrying out crushing to obtain a material to be calcined; and using a segmentation method to carry out high-temperature calcination on said material, and then carrying out crushing to obtain a titanium-based lithium ion sieve, wherein the high-temperature calcination temperature range is divided into four zones, i.e., a heating zone, a high-temperature reaction zone, a medium-temperature reaction zone, and a cooling zone. The present application aims to solve the problem of non-uniform and low performance of titanium-based lithium ion sieves in large-scale preparation processes.

Description

A method for preparing titanium-based lithium ion sieve, products prepared therefrom and applications thereof

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 202310679048.9 filed with the State Intellectual Property Office of China on June 8, 2023, entitled “A method for preparing a titanium-based lithium ion sieve, products prepared thereby, and applications thereof,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the field of lithium ion adsorption technology, and in particular to a method for preparing a titanium-based lithium ion sieve, and products and applications thereof. Background Art

[0004] Since the development of new energy technologies, lithium batteries have become the mainstream power source for renewable energy. Lithium is widely used in various electronic and electrical products. The rise of new energy vehicles in recent years has made lithium resources the "white oil" of the new era. Although China's lithium resources rank fourth globally, they primarily exist in the form of salt lakes, requiring complex processes to extract the lithium. In recent years, with the development of new lithium adsorbents and extractants, as well as the application of membrane processes, my country's salt lake lithium extraction technology has rapidly developed. Currently, domestic salt lake lithium extraction technology primarily relies on a combination of lithium adsorbents and membranes, making technological breakthroughs in lithium adsorbents crucial.

[0005] Currently, the synthesis of titanium-based lithium ion sieves primarily utilizes a high-temperature solid-phase method, which is simple, easy to operate, and readily scalable. However, the synthesis of titanium-based lithium ion sieves using this method requires the steps of "mixing the lithium and titanium sources," "drying the materials," "crushing the intermediate materials," "high-temperature calcination," and "crushing the finished product." These steps are prone to uneven mixing, material re-separation during drying, and improper sintering processes, leading to uneven and often subpar performance in titanium-based lithium ion sieve products.

[0006] CN115069209A discloses a titanium-based lithium ion sieve inorganic composite adsorption lithium extraction material and its preparation method. The method involves mixing the titanium-based lithium ion sieve or its precursor with a regulator, a curing agent, and a resin monomer. The polymer monomer undergoes a polymerization reaction at a specific temperature and gradually solidifies. During this process, particles of a specific shape are prepared by extrusion or spray drying. Subsequently, the material is calcined at high temperature in the absence of oxygen and treated with acid to obtain a carbon-supported titanium-based lithium ion sieve inorganic / inorganic composite lithium extraction material.

[0007] CN114345291A discloses a method for preparing a granular titanium-based lithium ion sieve adsorbent with high adsorption capacity. The method comprises the following steps: 1) preparing a titanium-based lithium ion sieve precursor powder; 2) preparing the granular titanium-based lithium ion sieve adsorbent with high adsorption capacity, 1) pre-treating the precursor powder; 2) preparing a composite glue; 3) doping, blending, and homogenizing; 4) forming and granulating; and 5) elution and replacement. The granular adsorbent has a high porosity and exhibits good suspension properties, fast adsorption and desorption rates, and high lithium extraction activity when extracting lithium in salt lake brine or simulated brine. However, the lithium source in this patent is lithium carbonate, which can easily lead to uneven mixing, a problem that is particularly prominent in industrialized and scaled-up production.

[0008] Therefore, to solve the problem of uneven mixing, the two powder materials cannot be directly mixed in a dry state; to solve the problem of material re-separation during the drying process, the mixed material liquid needs to have a certain viscosity to reduce the sedimentation of the powder material; to solve the problem of low product performance caused by improper sintering process during the sintering process, it is necessary to optimize the calcination temperature and calcination time to match the reaction thermodynamic and kinetic parameters of the titanium-based lithium ion sieve synthesis.

[0009] Summary of the Invention

[0010] The present application provides a method for preparing a titanium-based lithium ion sieve, which solves the problems of uneven mixing and re-separation of materials during the drying process in related technologies; and solves the problem of low product performance caused by improper sintering process during the sintering process.

[0011] The present application also provides a titanium-based lithium ion sieve prepared by the above method. The titanium-based lithium ion sieve has very small and uniform particle size and high adsorption capacity.

[0012] The present application also provides a use of the titanium-based lithium ion sieve for selectively identifying and / or extracting lithium ions from brine. The titanium-based lithium ion sieve has extremely high selectivity for lithium ions and can selectively extract lithium ions from brine, while having little adsorption of potassium, sodium, magnesium, and calcium ions.

[0013] Some embodiments of the present application provide a method for preparing a titanium-based lithium ion sieve, thereby at least solving the technical problems existing in the related art. The method for preparing the titanium-based lithium ion sieve provided in the embodiments of the present application may include the following steps:

[0014] (1) mixing a water-soluble lithium source, a titanium source, and a tackifier, and sequentially performing ball milling and sand milling to obtain a mixed slurry of the lithium source and the titanium source;

[0015] (2) drying and crushing the mixed slurry obtained in step (1) to obtain a material to be calcined;

[0016] (3) calcining the material to be calcined obtained in step (2) at high temperature by a segmented method and then crushing it to obtain a titanium-based lithium ion sieve;

[0017] The temperature range of the high temperature calcination is divided into four zones, including a heating zone, a high temperature reaction zone, a medium temperature reaction zone and a cooling zone; wherein the temperature of the heating zone is set to 100-750°C (for example, 100°C, 150°C, 200°C, 250°C, 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, etc.), and the temperature of the high temperature reaction zone is set to 950-1050°C (for example, The temperature of the medium-temperature reaction zone is set to 800-900°C (for example, it can be 800°C, 820°C, 840°C, 860°C, 880°C, 900°C, etc.), and the temperature of the cooling zone is set to 150-650°C (for example, it can be 150°C, 200°C, 250°C, 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, etc.).

[0018] In step (1) of the present application, a water-soluble lithium source is used as the lithium source instead of a water-insoluble lithium source (such as lithium carbonate), and mixed with the titanium source. The water-soluble lithium source will infiltrate and wrap the surface of the titanium dioxide, which can make the lithium source and the titanium source mix more fully, reduce the migration distance of lithium ions during the reaction, and increase the reaction rate.

[0019] In step (3) of the present application, sintering is carried out using a push plate kiln, and the temperature range of the push plate kiln is divided into four zones: a temperature rising zone, a high temperature reaction zone, a medium temperature reaction zone, and a temperature falling zone.

[0020] The materials will undergo the following reaction in this process: 2C6H5O7Li3+3TiO2+9O2=3Li2TiO3+5H2O+12CO2↑ (or 2Li2C2O4+2TiO2+O2=2Li2TiO3+4CO2↑)

[0021] The short residence time in the high-temperature reaction zone allows the reactants to nucleate in the high-temperature zone, producing a large number of nascent nuclei. These nuclei then enter the medium-temperature reaction zone, where they grow more regularly and completely, thereby improving adsorption capacity and selectivity. Optimizing the calcination temperature and time to match the reaction thermodynamic and kinetic parameters for the synthesis of titanium-based lithium ion sieves addresses the issue of low product performance caused by improper sintering processes.

[0022] Optionally, in step (1), the mass ratio of the water-soluble lithium source, the titanium source and the viscosity enhancer is (1-5):(1-5):(0.01-0.05);

[0023] The first "1-5" can be, for example, 1, 2, 3, 4, 5, etc.

[0024] The second "1-5" can be, for example, 1, 2, 3, 4, 5, etc.

[0025] Here, “0.01 to 0.05” may be, for example, 0.01, 0.02, 0.03, 0.04, 0.05, etc.

[0026] Optionally, the water-soluble lithium source is a lithium citrate solution and / or a lithium oxalate solution.

[0027] Optionally, the water-soluble lithium source is prepared by the following method: adding lithium hydroxide to water while stirring, then adding acid, and stirring to obtain a water-soluble lithium source solution.

[0028] Optionally, the mass ratio of water, lithium hydroxide and acid is (3-5):(1.5-2):(3.5-4.5);

[0029] Here, “3-5” can be, for example, 3, 3.5, 4, 4.5, 5, etc.;

[0030] Here, “1.5-2” can be, for example, 1.5, 1.6, 1.7, 1.8, 1.9, 2, etc.;

[0031] Here, “3.5-4.5” can be, for example, 3.5, 3.6, 3.8, 4, 4.2, 4.5, etc.

[0032] Optionally, the acid comprises citric acid and / or oxalic acid.

[0033] More specifically, the water-soluble lithium source is prepared by the following method:

[0034] ① Preparation of lithium citrate solution:

[0035] Deionized water is added to a stirring device. While stirring, lithium hydroxide powder is added, and then citric acid powder is added. The mixture is stirred at a speed of 100 to 600 rpm (for example, 100 rpm, 200 rpm, 300 rpm, 400 rpm, 500 rpm, etc.) for 1 to 3 hours (for example, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, etc.) to obtain a lithium citrate solution. The reaction equation of this process is: C6H8O7+3LiOH=C6H5O7Li3+3H2O;

[0036] ② Preparation of lithium oxalate solution:

[0037] Deionized water is added to a stirring device. While stirring, lithium hydroxide powder is added, and then dihydrated oxalic acid powder is added. The mixture is stirred at a speed of 100 to 600 rpm (for example, 100 rpm, 200 rpm, 300 rpm, 400 rpm, 500 rpm, etc.) for 1 to 3 hours (for example, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, etc.) to obtain a lithium oxalate solution. The reaction equation of this process is: H2C2O4·2H2O+2LiOH=Li2C2O4+4H2O;

[0038] Optionally, in step (1), the titanium source includes rutile titanium dioxide and / or anatase titanium dioxide.

[0039] Optionally, in step (1), the particle size of the titanium source is 50 to 500 nm, for example, it can be 50 nm, 60 nm, 80 nm, 100 nm, 120 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, etc.

[0040] In step (1) of the present application, optionally, rutile titanium dioxide (or anatase titanium dioxide) with a particle size of nanometer level is easy to agglomerate in an aqueous solution. By first ball milling and then sand milling in an aqueous phase system, the agglomerated titanium dioxide is ground and dispersed, so that the titanium dioxide particles are in more sufficient contact with the water-soluble lithium source, and the two materials can also be mixed more evenly, which is beneficial to the uniformity of product performance.

[0041] Optionally, in step (1), the viscosity enhancer includes any one of polyethylene glycol, povidone, polyvinyl alcohol or hydroxyethyl cellulose or a combination of at least two thereof, and further optionally is polyethylene glycol.

[0042] Optionally, the number average molecular weight of the polyethylene glycol is 200-800, for example, 200, 300, 400, 500, 600, 700, 800, etc., and further optionally, 400-600.

[0043] In step (1) of the present application, polyethylene glycol can be optionally used as a thickener, and PEG-400 (or PEG-600) can be further selected. This is because compared with other types of thickeners, it not only increases the viscosity of the feed liquid, but also helps prevent the precipitation of titanium dioxide in the aqueous solution, and helps the water-soluble lithium source and titanium source materials to be uniformly dispersed without stratification during microwave drying; it can also maintain the viscosity of the feed liquid within an appropriate range of 200-500mPas, so that the viscosity is not too high and causes difficulties in ball milling and sand milling.

[0044] Optionally, in step (1), the rotation speed of mixing the lithium source, titanium source and viscosity enhancer is 100 to 600 rpm (for example, 100 rpm, 200 rpm, 300 rpm, 400 rpm, 500 rpm, etc.), and the mixing time is 2 to 4 h, for example, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, etc.

[0045] Optionally, in step (1), the ball mill uses zirconium dioxide balls with a diameter of 2 to 8 mm (for example, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, or 8 mm), the ball milling speed is 30 to 90 rpm (for example, 30 rpm, 40 rpm, 50 rpm, 60 rpm, 70 rpm, 80 rpm, or 90 rpm, etc.), and the ball milling time is 3 to 5 h, for example, 3 h, 3.5 h, 4 h, 4.5 h, or 5 h, etc.

[0046] Optionally, in step (1), after the ball milling, the feed liquid needs to be fed into a sand mill in one direction at a feed rate of 10 to 20 L / min (for example, 10 L / min, 12 L / min, 14 L / min, 16 L / min, 18 L / min, 20 L / min, etc.) for grinding.

[0047] Optionally, in step (1), the sanding speed is 500-1000 rpm (for example, 500 rpm, 600 rpm, 700 rpm, 800 rpm, 900 rpm, 1000 rpm, etc.), and the number of sanding is 5-10 times, for example, 5 times, 6 times, 7 times, 8 times, 9 times, 10 times, etc.

[0048] Optionally, in step (2), the drying is microwave drying.

[0049] In step (2) of the present application, microwave drying is selected because the use of a microwave dryer to dry the liquid material can prevent the stratification or sedimentation of the water-soluble lithium source solution and titanium dioxide due to excessive drying time, thereby ensuring uniform dispersion of the material and improving drying efficiency.

[0050] Optionally, in step (2), the feed rate of the mixed slurry is 80-100 kg / h, for example, 80 kg / h, 85 kg / h, 90 kg / h, 95 kg / h, 100 kg / h, etc.

[0051] Optionally, in step (2), the microwave drying power is 100-200 kW, for example, it can be 100 kW, 120 kW, 140 kW, 160 kW, 180 kW, 200 kW, etc.; the microwave drying time is 0.5-1 h, for example, it can be 0.5 h, 0.6 h, 0.7 h, 0.8 h, 0.9 h, 1 h, etc.

[0052] Optionally, in step (2), the moisture content of the material to be calcined is 0.1-0.5%, for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, etc.

[0053] Optionally, in step (2), the crushing is performed after sieving, and further optionally, the sieve is 50-100 mesh (50 mesh, 60 mesh, 70 mesh, 80 mesh, 90 mesh, 100 mesh).

[0054] Optionally, in step (3), a push plate kiln is used for high-temperature calcination and then crushing to obtain a titanium-based lithium ion sieve.

[0055] Optionally, in step (3), the total length of the push plate kiln is 28 to 42 m, for example, 28 m, 30 m, 32 m, 34 m, 36 m, 38 m, 40 m, 42 m, etc.

[0056] Optionally, in step (3), the heating zone is divided into 5 sections, each section is 2 to 3 m long (for example, it can be 2 m, 2.2 m, 2.4 m, 2.5 m, 2.6 m, 2.8 m, 3 m, etc.), and the temperature settings of the 5 heating zones are 100 to 150 ° C, 250 to 300 ° C, 400 to 450 ° C, 550 to 600 ° C, and 700 to 750 ° C, respectively. The total residence time of the material in the heating zone is 4 to 5 h (for example, it can be 4 h, 4.2 h, 4.6 h, 4.8 h, 5 h, etc.).

[0057] Optionally, in step (3), the high-temperature reaction zone is 1 section with a section length of 2 to 3 m (for example, 2 m, 2.2 m, 2.4 m, 2.5 m, 2.6 m, 2.8 m, 3 m, etc.), the temperature of the high-temperature reaction zone is set to 950-1050 ° C, and the residence time of the material in the high-temperature reaction zone is 0.8-1 h (for example, 0.8 h, 0.85 h, 0.9 h, 0.95 h, 1 h, etc.).

[0058] Optionally, in step (3), the medium-temperature reaction zone is divided into four sections, each section is 2 to 3 m long (for example, it can be 2 m, 2.2 m, 2.4 m, 2.5 m, 2.6 m, 2.8 m, 3 m, etc.), and the temperature settings of the four medium-temperature reaction zones are 800-900 ° C, 800-900 ° C, 800-900 ° C, and 800-900 ° C, respectively. The residence time of the material in the medium-temperature reaction zone is 3.2-4 h (for example, it can be 3.2 h, 3.4 h, 3.6 h, 3.8 h, 4 h, etc.).

[0059] Optionally, in step (3), the cooling zone is divided into four sections, each section is 2 to 3 m long (for example, it can be 2 m, 2.2 m, 2.4 m, 2.5 m, 2.6 m, 2.8 m, 3 m, etc.), and the temperature settings of the four cooling zones are 600-650 ° C, 450-500 ° C, 300-350 ° C, and 150-200 ° C, respectively. The residence time of the material in the cooling zone is 3.2-4 h (for example, it can be 3.2 h, 3.4 h, 3.6 h, 3.8 h, 4 h, etc.).

[0060] In the present application, by further setting the temperature range of the push plate kiln as described above, as specifically shown in FIG1 , the reaction thermodynamic and kinetic parameters of the titanium-based lithium ion sieve synthesis are matched by optimizing the calcination temperature and calcination time, and the reaction nucleation is carried out in the high temperature zone, and the nucleus growth and crystal perfection are carried out in the medium temperature zone.

[0061] After the material is preheated in the first five heating zones, it enters the high-temperature zone. During the reaction between the lithium source and the titanium source, the lithium ions in the lithium source migrate into the titanium dioxide crystals. From the analysis of reaction thermodynamics, when the lithium ions are first intercalated and occupy positions on the titanium dioxide crystals, the required reaction energy (activation energy) is relatively large. The higher the temperature, the more conducive it is to the formation of a primary transition state structure between lithium ions and titanium dioxide. The explosive formation of a large number of primary transition state structures is conducive to the formation of more lithium intercalation sites and the improvement of the adsorption capacity of the synthetic titanium-based lithium ion sieve. The material should not be in the high-temperature zone for too long, otherwise it will easily cause the material to form overly large crystals at high temperatures, reducing the adsorption capacity.

[0062] The material then enters the four-stage medium-temperature reaction zone. The reactions in this zone primarily involve the secondary growth and crystal perfection of the transitional structure formed in the high-temperature zone. Reaction kinetics suggest that this secondary growth and crystal perfection require lower temperatures and longer times. Lower temperatures favor independent growth and perfection of crystals at appropriate energy levels, rather than agglomerated growth and perfection at high temperatures and high energy levels. Longer times facilitate deep migration of lithium ions within the crystals within the titanium dioxide, forming a perfect crystalline structure and improving the selectivity of titanium-based lithium ion sieves. Optimizing the calcination temperature and time to match the reaction thermodynamic and kinetic parameters for titanium-based lithium ion sieve synthesis addresses the issue of low product performance resulting from improper sintering techniques.

[0063] Optionally, in step (3), the crushing is followed by sieving, and further optionally, the sieving is performed through a 100-200 mesh sieve (for example, 100 mesh, 120 mesh, 150 mesh, 180 mesh, 200 mesh, etc.).

[0064] Other embodiments of the present application provide a titanium-based lithium ion sieve, which is prepared by the preparation method of the titanium-based lithium ion sieve described in some embodiments of the present application.

[0065] The crystal form of the titanium-based lithium ion sieve prepared by the titanium preparation method described in some embodiments of the present application is β-Li2TiO3 crystal form. The crystal form of the titanium-based lithium ion sieve synthesized in this process is single and free of other impurities.

[0066] Still other embodiments of the present application provide a use of a titanium-based lithium ion sieve as described in the other embodiments above in the selective identification and / or extraction of lithium ions in brine.

[0067] Compared with the related art, this application has at least the following beneficial effects:

[0068] (1) The present application utilizes a water-soluble lithium source instead of water-insoluble lithium carbonate as a lithium source, and mixes it with water-insoluble titanium dioxide. The water-soluble lithium citrate will infiltrate and wrap the surface of the titanium dioxide, which can make the lithium source and the titanium source mix more fully, reduce the migration distance of lithium ions during the reaction process, and increase the reaction rate;

[0069] (2) The rutile titanium dioxide (or anatase titanium dioxide) is nanometer-sized and easily aggregates in an aqueous solution. The agglomerated titanium dioxide is ground and dispersed by first ball milling and then sand milling in an aqueous phase system, so that the titanium dioxide particles are in more complete contact with the water-soluble lithium citrate and the two materials are mixed more evenly, which is beneficial to the uniformity of product performance.

[0070] (3) The present application increases the viscosity of the feed solution by adding a thickener, which helps prevent the precipitation of titanium dioxide in the aqueous solution and helps the lithium citrate and titanium dioxide to be evenly dispersed without stratification during the microwave drying process;

[0071] (4) The present application uses a microwave dryer to dry the liquid material, which can prevent the lithium citrate solution and titanium dioxide from stratifying or settling due to excessive drying time, ensuring uniform dispersion of the material and improving drying efficiency;

[0072] (5) This application uses a push plate kiln for sintering. The temperature range of the push plate kiln is divided into four zones: a heating zone, a high-temperature reaction zone, a medium-temperature reaction zone, and a cooling zone. The residence time in the high-temperature reaction zone is short, mainly to allow the reaction materials to react and nucleate in the high-temperature zone, resulting in a large number of primary crystal nuclei, and then enter the medium-temperature reaction zone, allowing these crystal nuclei to grow more regularly and completely in the medium-temperature zone, which is conducive to improving the adsorption capacity and selectivity. The reaction thermodynamic and kinetic parameters of the titanium-based lithium ion sieve synthesis are matched by optimizing the calcination temperature and calcination time to solve the problem of low product performance caused by improper sintering process in the sintering process. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] In order to more clearly illustrate the specific implementation methods of this application or the technical solutions in related technologies, the following is a brief introduction to the drawings required for use in the specific implementation methods or related technical descriptions. Obviously, the drawings described below are some implementation methods of this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0074] FIG1 is a diagram showing the temperature zone layout and temperature setting of a push plate kiln provided in this application.

[0075] FIG2 is a SEM photograph of the titanium-based lithium ion sieve prepared according to Example 1 of the present application.

[0076] FIG3 is an XRD pattern of the titanium-based lithium ion sieve prepared according to Example 1 of the present application.

[0077] FIG4 is a graph showing the adsorption capacity of samples of the titanium-based lithium ion sieve provided in Example 1 of the present application at different time periods during the calcination process.

[0078] FIG5 is a SEM photograph of the titanium-based lithium ion sieve prepared according to Example 2 of the present application.

[0079] FIG6 is an XRD pattern of the titanium-based lithium ion sieve prepared according to Example 2 of the present application.

[0080] FIG7 is a graph showing the adsorption capacity of samples of the titanium-based lithium ion sieve provided in Example 2 of the present application at different time periods during the calcination process.

[0081] FIG8 is a SEM photograph of the titanium-based lithium ion sieve prepared according to Example 3 of the present application.

[0082] FIG9 is an XRD pattern of the titanium-based lithium ion sieve prepared according to Example 3 of the present application.

[0083] FIG10 is a graph showing the adsorption capacity of samples of the titanium-based lithium ion sieve provided in Example 3 of the present application at different time periods during the calcination process. DETAILED DESCRIPTION

[0084] Unless otherwise defined herein, scientific and technical terms used in conjunction with this application shall have the meanings commonly understood by those of ordinary skill in the art. The meaning and scope of the terms should be clear; however, in the event of any potential ambiguity, the definitions provided herein take precedence over any dictionary or external definitions. In this application, unless otherwise indicated, the use of "or" means "and / or." Furthermore, the use of the term "including" and other forms is non-limiting.

[0085] Generally, the nomenclature used together with cell and tissue culture, molecular biology, immunology, microbiology, genetics and protein and nucleic acid chemistry and hybridization described herein and its technology are well-known in the art and those commonly used.Unless otherwise noted, the method and technology of the present application are generally according to well-known in the art, and are carried out as the conventional method described in various general and more specific references, which are quoted and discussed throughout this specification.Enzymatic reaction and purification techniques are carried out according to the manufacturer's specifications, as usually realized in this area or as described herein.The nomenclature used together with analytical chemistry, synthetic organic chemistry and medical and pharmaceutical chemistry described herein and its laboratory procedures and technology are well-known in the art and those commonly used.

[0086] The following will clearly and completely describe the technical solutions of this application in conjunction with the embodiments. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0087] The present invention is further described below by way of examples. Unless otherwise specified, the materials in the examples were prepared according to existing methods or purchased directly from the market.

[0088] Example 1

[0089] This embodiment provides a method for preparing a titanium-based lithium ion sieve, which comprises the following steps:

[0090] (1) Add 350 kg of deionized water to a stirring barrel, add 140 kg of lithium hydroxide powder while stirring, then add 380 kg of citric acid powder, and stir at a speed of 100 rpm for 1 hour to obtain a lithium citrate solution;

[0091] 5 kg of PEG-400 and 240 kg of rutile titanium dioxide powder (particle size of 50 nm) were added to the lithium citrate solution and stirred at a speed of 100 rpm for 2 h to obtain a liquid with a viscosity of 200 mPas; the liquid was then transferred to a ball mill, and the mixture was ball-milled at a speed of 30 rpm for 3 h using 2 mm diameter zirconium dioxide balls as grinding bodies; the liquid was then passed into a sand mill in one direction and ground at a speed of 500 rpm, with a feed rate of 10 L / min. The discharge of the sand mill was loaded with another stirring barrel and sand-milled 5 times to obtain a mixed slurry of lithium source and titanium source;

[0092] (2) The mixed slurry of the lithium source and the titanium source is passed through the track of a microwave dryer (power of 150 kW). The drying time of the mixed slurry in the microwave dryer is 0.5 h, the feed rate of the mixed slurry is 80 kg / h, and the moisture content of the dry bulk material after microwave drying is 0.1%; the dry bulk material is then placed in a grinder for crushing and passed through a 50-mesh sieve to obtain a dry powder material to be calcined;

[0093] (3) The dry powder material to be calcined is placed in a mullite crucible, 3 kg per crucible, and placed in a pusher kiln for high-temperature calcination. The pusher kiln is 35 meters long and has a temperature range of four zones: a heating zone, a high-temperature reaction zone, a medium-temperature reaction zone, and a cooling zone. The heating zone is divided into 5 sections, each 2.5m long, and the temperature settings of the 5 sections are 100℃, 250℃, 400℃, 550℃, and 700℃ respectively. The total residence time of the material in the heating zone is 4h; then it enters the high-temperature reaction zone, which has only one section, 2.5m long, and the temperature of the high-temperature section is set to 950℃. The residence time of the material in the high-temperature zone is 0.8h; then it enters the medium-temperature reaction zone, which is divided into 4 sections, each 2.5m long, and the temperature settings of the 4 sections are 800℃, 800℃, 800℃, and 800℃ respectively. The total residence time of the material in the medium-temperature reaction zone is 3.2h; then it enters the cooling zone, which has 4 sections, each 2.5m long, and the temperature settings of the 4 sections are 600℃, 450℃, 300℃, and 150℃ respectively. The total residence time of the material in the medium-temperature reaction zone is 3.2h;

[0094] Finally, the calcined material is placed in a grinder for pulverization, and passed through a 100-mesh sieve to obtain titanium-based lithium ion sieve powder.

[0095] Figure 2 is an SEM photograph of the titanium-based lithium ion sieve prepared according to Example 1 of the present application. As can be seen from Figure 2, the particle size of the titanium-based lithium ion sieve prepared in Example 1 is 100-300 nm, the particle size is very small, and the particle size is uniform, which is conducive to improving the adsorption capacity of the titanium-based lithium ion sieve.

[0096] Figure 3 is an XRD pattern of the titanium-based lithium ion sieve prepared according to Example 1 of the present application. It can be seen from Figure 3 that the crystal form of the titanium-based lithium ion sieve is β-Li2TiO3 crystal form, which proves that the crystal form of the titanium-based lithium ion sieve prepared in Example 1 is single and contains no other impurities.

[0097] Figure 4 is a graph showing the adsorption capacity of samples of the titanium-based lithium ion sieve provided in Example 1 of the present application at different time periods during the calcination process. During the continuous production process, a sample of the titanium-based lithium ion sieve is taken every 5 hours, acidified with hydrochloric acid to obtain β-H2TiO3, and the adsorption capacity of the titanium-based lithium ion sieve is tested using β-H2TiO3. As can be seen from Figure 4, the titanium-based lithium ion sieve product prepared in Example 1 has uniform performance, an average saturated adsorption capacity of 55 mg / g, and has the characteristic of large adsorption capacity.

[0098] Example 2

[0099] This embodiment provides a method for preparing a titanium-based lithium ion sieve, which comprises the following steps:

[0100] (1) Add 400 kg of deionized water to a stirring barrel, add 180 kg of lithium hydroxide powder while stirring, then add 420 kg of citric acid powder, and stir at a speed of 600 rpm for 3 hours to obtain a lithium citrate solution;

[0101] 10 kg of PEG-600 and 280 kg of anatase titanium dioxide powder (particle size of 500 nm) were added to the lithium citrate solution and stirred at 600 rpm for 4 h to obtain a liquid with a viscosity of 400 mPas; the liquid was then transferred to a ball mill, and the mixture was ball-milled at 90 rpm for 5 h using 8 mm diameter zirconium dioxide balls as grinding bodies; the liquid was then passed into a sand mill in one direction and ground at 1000 rpm with a feed rate of 20 L / min. The discharge of the sand mill was loaded with another stirring barrel and sand-milled 10 times to obtain a mixed slurry of lithium source and titanium source;

[0102] (2) The mixed slurry of the lithium source and the titanium source is passed onto the track of a microwave dryer (power of 150 kW). The drying time of the mixed slurry in the microwave dryer is 1 hour, the feed rate of the mixed slurry is 100 kg / h, and the moisture content of the dry bulk material after microwave drying is 0.5%; then, the bulk material after microwave drying is placed in a grinder for crushing and passed through a 100-mesh sieve to obtain a dry powder material to be calcined;

[0103] (3) The dry powder material to be calcined is placed in a mullite crucible, 4 kg per crucible, and placed in a pusher kiln for high-temperature calcination. The pusher kiln is 35 meters long and has a temperature range of four zones: a heating zone, a high-temperature reaction zone, a medium-temperature reaction zone, and a cooling zone. The heating zone is divided into 5 sections, each 2.5m long, and the temperature settings of the 5 sections are 150℃, 300℃, 450℃, 600℃, and 750℃ respectively. The total residence time of the material in the heating zone is 5h; then it enters the high-temperature reaction zone, which has only one section, 2.5m long, and the temperature of the high-temperature section is set to 1050℃. The residence time of the material in the high-temperature zone is 1h; then it enters the medium-temperature reaction zone, which is divided into 4 sections, each 2.5m long, and the temperature settings of the 4 sections are 900℃, 900℃, 900℃, and 900℃ respectively. The total residence time of the material in the medium-temperature reaction zone is 4h; then it enters the cooling zone, which has 4 sections, each 2.5m long, and the temperature settings of the 4 sections are 650℃, 500℃, 350℃, and 200℃ respectively. The total residence time of the material in the medium-temperature reaction zone is 4h;

[0104] Finally, the calcined material is placed in a grinder for pulverization, and passed through a 200-mesh sieve to obtain titanium-based lithium ion sieve powder.

[0105] Figure 5 is an SEM photograph of the titanium-based lithium ion sieve prepared according to Example 2 of the present application. As can be seen from Figure 5, the particle size of the titanium-based lithium ion sieve synthesized in the present application is 100-300 nm, the particle size is very small, and the particle size is uniform, which is conducive to improving the adsorption capacity of the titanium-based lithium ion sieve.

[0106] Figure 6 is an XRD pattern of the titanium-based lithium ion sieve prepared according to Example 2 of the present application. It can be seen from Figure 6 that the crystal form of the titanium-based lithium ion sieve prepared in Example 2 is a β-Li2TiO3 crystal form, which proves that the crystal form of the titanium-based lithium ion sieve synthesized under the process of this invention is single and contains no other impurities.

[0107] Figure 7 is a graph showing the adsorption capacity of samples of the titanium-based lithium ion sieve provided in Example 2 of the present application at different time periods during the calcination process. During the continuous production process, a sample of the titanium-based lithium ion sieve is taken every 5 hours, acidified with hydrochloric acid to obtain β-H2TiO3, and the adsorption capacity of the titanium-based lithium ion sieve is tested using β-H2TiO3. As can be seen from Figure 7, the titanium-based lithium ion sieve product prepared in Example 2 has uniform performance, an average saturated adsorption capacity of 56 mg / g, and has the characteristic of large adsorption capacity.

[0108] Example 3

[0109] This embodiment provides a method for preparing a titanium-based lithium ion sieve, which comprises the following steps:

[0110] (1) Add 380 kg of deionized water to a stirring barrel, add 160 kg of lithium hydroxide powder while stirring, then add 450 kg of oxalic acid dihydrate powder, and stir at a speed of 350 rpm for 2 h to obtain a lithium oxalate solution;

[0111] 7.5 kg of PEG-600 and 260 kg of anatase titanium dioxide powder (particle size of 100 nm) were added to the lithium oxalate solution and stirred at 350 rpm for 3 h to obtain a solution with a viscosity of 300 mPas; the solution was then transferred to a ball mill, and the mixture was ball-milled at 60 rpm for 4 h using 5 mm diameter zirconium dioxide balls as grinding bodies; the solution was then passed into a sand mill in one direction and ground at 750 rpm with a feed rate of 15 L / min. The discharge of the sand mill was loaded with another stirring barrel and sand-milled 8 times to obtain a mixed slurry of lithium source and titanium source;

[0112] (2) The mixed slurry of the lithium source and the titanium source was passed onto the track of a microwave dryer (power of 150 kW). The drying time of the mixed slurry in the microwave dryer was 0.75 h, the feed rate of the mixed slurry was 90 kg / h, and the moisture content of the dry bulk material after microwave drying was 0.3%; then, the bulk material after microwave drying was placed in a grinder for crushing and passed through an 80-mesh sieve to obtain a dry powder material to be calcined;

[0113] (3) The dry powder material to be calcined is placed in a mullite crucible, 3.5 kg per crucible, and placed in a pusher kiln for high-temperature calcination. The pusher kiln is 35 meters long and has a temperature range of four zones: a heating zone, a high-temperature reaction zone, a medium-temperature reaction zone, and a cooling zone. The heating zone is divided into 5 sections, each 2.5m long, and the temperature settings of the 5 sections are 125℃, 275℃, 425℃, 575℃, and 725℃ respectively. The total residence time of the material in the heating zone is 4.5h; then it enters the high-temperature reaction zone, which has only one section, 2.5m long, and the temperature of the high-temperature section is set to 1000℃. The residence time of the material in the high-temperature zone is 0.9h; then it enters the medium-temperature reaction zone, which is divided into 4 sections, each 2.5m long, and the temperature settings of the 4 sections are 850℃, 850℃, 850℃, and 850℃ respectively. The total residence time of the material in the medium-temperature reaction zone is 3.6h; then it enters the cooling zone, which has 4 sections, each 2.5m long, and the temperature settings of the 4 sections are 625℃, 475℃, 325℃, and 175℃ respectively. The total residence time of the material in the medium-temperature reaction zone is 3.6h;

[0114] Finally, the calcined material is placed in a grinder for pulverization, and passed through a 150-mesh sieve to obtain titanium-based lithium ion sieve powder.

[0115] Figure 8 is an SEM photograph of the titanium-based lithium ion sieve prepared according to Example 3 of the present application. As can be seen from Figure 8, the particle size of the titanium-based lithium ion sieve prepared in Example 3 is 100-300 nm, the particle size is very small, and the particle size is uniform, which is conducive to improving the adsorption capacity of the titanium-based lithium ion sieve.

[0116] Figure 9 is an XRD pattern of the titanium-based lithium ion sieve prepared according to Example 3 of the present application. It can be seen from Figure 9 that the crystal form of the titanium-based lithium ion sieve prepared in Example 3 is a β-Li2TiO3 crystal form, which proves that the crystal form of the titanium-based lithium ion sieve synthesized under the process of this invention is single and contains no other impurities.

[0117] Figure 10 is a graph showing the adsorption capacity of samples of the titanium-based lithium ion sieve provided in Example 3 of the present application at different time periods during the calcination process. During the continuous production process, a sample of the titanium-based lithium ion sieve is taken every 5 hours, acidified with hydrochloric acid to obtain β-H2TiO3, and the adsorption capacity of the titanium-based lithium ion sieve is tested using β-H2TiO3. As can be seen from Figure 10, the titanium-based lithium ion sieve product prepared in Example 3 has uniform performance, an average saturated adsorption capacity of 56 mg / g, and has a large adsorption capacity.

[0118] Example 4

[0119] This embodiment provides a method for preparing a titanium-based lithium ion sieve. The only difference from Example 1 is that the titanium source in step (1) is replaced by titanic acid of equal mass with a particle size D50 of 1.2 μm. The other steps are exactly the same as Example 1.

[0120] Example 5

[0121] This embodiment provides a method for preparing a titanium-based lithium ion sieve. The only difference from Example 1 is that the viscosity enhancer in step (1) is replaced by PEG-200 of equal mass. The other steps are exactly the same as those in Example 1. Step (1) obtains a slurry with a viscosity of 100 mPas.

[0122] Example 6

[0123] This embodiment provides a method for preparing a titanium-based lithium ion sieve. The only difference from Example 1 is that the viscosity enhancer in step (1) is replaced by PEG-800 of equal mass, and step (1) obtains a slurry with a viscosity of 550 mPas. The other steps are exactly the same as in Example 1.

[0124] Example 7

[0125] This embodiment provides a method for preparing a titanium-based lithium ion sieve. The only difference from Example 1 is that the viscosity enhancer in step (1) is replaced by PVA-400 of equal mass, and the other steps are exactly the same as Example 1.

[0126] Example 8

[0127] This embodiment provides a method for preparing a titanium-based lithium ion sieve. The only difference from Example 1 is that the feed rate of the mixed slurry is 60 kg / h, the drying time is 1.5 h, and the other steps are exactly the same as Example 1. The moisture content of the material to be calcined is 0.1%.

[0128] Example 9

[0129] This embodiment provides a method for preparing a titanium-based lithium ion sieve. The only difference from Example 1 is that the feed rate of the mixed slurry is 120 kg / h, the drying time is 0.4 h, and the other steps are exactly the same as Example 1. The moisture content of the material to be calcined is 7%.

[0130] Example 10

[0131] This embodiment provides a method for preparing a titanium-based lithium ion sieve. The only difference from Example 1 is that the temperatures of the five heating zones are set to 160°C, 320°C, 460°C, 620°C, and 760°C, respectively. The other steps are exactly the same as those in Example 1.

[0132] Example 11

[0133] This embodiment provides a method for preparing a titanium-based lithium ion sieve. The only difference from Example 1 is that the temperatures of the five heating zones are set to 80°C, 200°C, 350°C, 500°C, and 650°C, respectively. The other steps are exactly the same as those in Example 1.

[0134] Example 12

[0135] This embodiment provides a method for preparing a titanium-based lithium ion sieve. The only difference from Example 1 is that the heating zone is divided into only four sections, and the temperature settings of the four sections are 100°C, 300°C, 500°C, and 700°C, respectively. The other steps are exactly the same as those in Example 1.

[0136] Example 13

[0137] This embodiment provides a method for preparing a titanium-based lithium ion sieve. The only difference from Example 1 is that the medium-temperature reaction zone is divided into three sections, and the temperatures of the three sections are set to 850°C, 850°C, and 850°C, respectively. The other steps are exactly the same as those in Example 1.

[0138] Example 14

[0139] This embodiment provides a method for preparing a titanium-based lithium ion sieve. The only difference from Example 1 is that the temperatures of the four sections in the cooling zone are set to 660°C, 520°C, 360°C, and 220°C, respectively. The other steps are exactly the same as those in Example 1.

[0140] Example 15

[0141] This embodiment provides a method for preparing a titanium-based lithium ion sieve. The only difference from Example 1 is that the temperatures of the four sections in the cooling zone are set to 580°C, 420°C, 280°C, and 120°C, respectively. The other steps are exactly the same as those in Example 1.

[0142] Example 16

[0143] This embodiment provides a method for preparing a titanium-based lithium ion sieve. The only difference from Example 1 is that the cooling zone is divided into three sections, and the temperatures of the three sections are set to 600°C, 400°C, and 200°C, respectively. The other steps are exactly the same as Example 1.

[0144] Comparative Example 1

[0145] This comparative example provides a method for preparing a titanium-based lithium ion sieve, which differs from Example 1 only in that the lithium citrate solution is replaced with 215.8 kg of lithium carbonate powder during mixing in step (1), and the other steps are exactly the same as in Example 1.

[0146] Comparative Example 2

[0147] This comparative example provides a method for preparing a titanium-based lithium ion sieve, which differs from Example 1 only in that PEG-400 is not added during mixing in step (1), and the other steps are exactly the same as in Example 1.

[0148] Comparative Example 3

[0149] This comparative example provides a method for preparing a titanium-based lithium ion sieve. The only difference from Example 1 is that in step (1), the ball milling time in the ball mill is extended to 5 hours, and sand milling is no longer performed. The other steps are exactly the same as in Example 1.

[0150] Comparative Example 4

[0151] This comparative example provides a method for preparing a titanium-based lithium ion sieve. The only difference from Example 1 is that in step (2), a microwave dryer is not used for drying, but the material is dried in an oven at 200°C for 24 hours. The moisture content of the dried block material after drying is 3%. The other steps are exactly the same as in Example 1.

[0152] Comparative Example 5

[0153] This comparative example provides a method for preparing a titanium-based lithium ion sieve. The only difference from Example 1 is that after the high-temperature reaction, no medium-temperature reaction is carried out, but the material directly enters the cooling zone, and the residence time of the material in the high-temperature zone is adaptively extended. Specifically, the high-temperature reaction zone has only one section, which is 2.5 m long. The temperature of the high-temperature section is set to 950°C, and the residence time of the material in the high-temperature zone is 4 h. The other steps are exactly the same as in Example 1.

[0154] Comparative Example 6

[0155] This comparative example provides a method for preparing a titanium-based lithium ion sieve. The only difference from Example 1 is that a high-temperature reaction is no longer performed, and a medium-temperature reaction is directly performed after heating. The temperature of the medium-temperature zone is adaptively increased and the residence time of the material in the medium-temperature zone is extended. Specifically, the medium-temperature reaction zone is divided into 4 sections, each section is 2.5 m long, and the temperatures of the 4 sections are set to 850°C, 850°C, 850°C, and 850°C, respectively. The residence time of the material in the medium-temperature reaction zone is 4 h. The other steps are exactly the same as those in Example 1.

[0156] Comparative Example 7

[0157] This comparative example provides a preparation method of a titanium-based lithium ion sieve. The only difference from Example 1 is that a push plate kiln is no longer used for high-temperature calcination followed by crushing. Instead, a one-stage calcination is performed directly at 800°C for 12 hours. The other steps are exactly the same as in Example 1.

[0158] Test Example 1

[0159] Adsorption capacity test

[0160] Test samples: finished products of titanium-based lithium ion sieves prepared in Examples 1 to 16, and finished products of titanium-based lithium ion sieves prepared in Comparative Examples 1 to 7;

[0161] The test method is as follows: 2g of titanium-based lithium ion sieving agent is placed in 1000mL of real brine with a lithium ion concentration of 280.52mg / L, shaken for 10h, and the lithium ion concentration in the solution before and after adsorption is measured by ICP to calculate the adsorption capacity;

[0162] The specific test results are shown in Table 1 below:

[0163] Table 1

[0164] It can be seen from the test results in Table 1 that the titanium-based lithium ion sieve product obtained by the optimal process route of the present application has uniform performance, an average adsorption capacity of more than 55 mg / g, and has the characteristic of large adsorption capacity.

[0165] From the comparison between Example 1 and Example 4, it can be seen that the titanium source of the present application can optionally be nano-titanium dioxide. The titanium-based lithium ion sieve prepared from nano-titanium dioxide has a smaller particle size than micron-level metatitanic acid, which allows the titanium dioxide particles to contact the water-soluble lithium source more fully. At the same time, it can also make the two materials mix more evenly, which is more conducive to the formation of more lithium intercalation sites, thereby significantly improving the average adsorption capacity of the product.

[0166] From the comparison between Example 1 and Examples 5 to 6, it can be seen that the molecular weight of polyethylene glycol can be optionally 400 to 600, and the average adsorption capacity is large; if the molecular weight is too low, the viscosity-increasing effect is poor, titanium dioxide settles in the aqueous solution, and the water-soluble lithium source and titanium source are easily stratified and evenly dispersed during microwave drying; if the molecular weight is too high, the viscosity will be too high, which will make ball milling and sand milling difficult, and will also lead to insufficient contact between the titanium dioxide particles and the water-soluble lithium source and uneven mixing.

[0167] From the comparison between Example 1 and Example 7, it can be seen that the thickening agent of the present application optionally uses polyethylene glycol, but when it is replaced with PVA of equal mass or molecular weight, the thickening effect is poor, and its effect of preventing titanium dioxide from settling in aqueous solution is extremely weak.

[0168] From the comparison between Example 1 and Examples 8 and 9, it can be seen that the feed rate of the mixed slurry into the microwave drying should be in the range of 80-100 kg / h. Otherwise, even if the speed is reduced to extend the drying time, or the speed is increased to shorten the drying time, it will lead to insufficient drying and the material cannot be evenly dispersed.

[0169] From the comparison between Example 1 and Example 12, it can be seen that if the heating zone is divided into only four sections, the heating rate is too fast, which is not conducive to more regular and complete growth of the crystal nuclei in the later stage, resulting in a decrease in adsorption capacity.

[0170] From the comparison between Example 1 and Example 13, it can be seen that if the medium-temperature reaction zone is divided into only three sections, the section temperatures of the medium-temperature reaction zone are not within the scope of this application, and the growth in the medium-temperature zone will also be irregular and defective.

[0171] From the comparison between Example 1 and Comparative Example 1, it can be seen that when the lithium source is lithium carbonate, the problem of uneven mixing is prone to occur, which is particularly prominent in industrial and scaled-up production. In contrast, in the embodiment, a water-soluble lithium source is used instead of a water-insoluble lithium source (such as lithium carbonate) as the lithium source, and mixed with a titanium source. The water-soluble lithium source will infiltrate and coat the surface of the titanium dioxide, which can make the lithium source and the titanium source mix more fully, reduce the migration distance of lithium ions during the reaction, and increase the reaction rate.

[0172] From the comparison between Example 1 and Comparative Example 2, it can be seen that if no viscosity enhancer is added, titanium dioxide has a serious sedimentation problem in the aqueous solution. During the microwave drying process, the water-soluble lithium source and titanium source are easily separated and evenly dispersed.

[0173] From the comparison between Example 1 and Comparative Example 3, it can be seen that without sand milling, even if the ball milling time is extended, the agglomerated titanium dioxide cannot be well ground and dispersed, the contact with the water-soluble lithium source is insufficient, and the uniformity of product performance is poor.

[0174] From the comparison between Example 1 and Comparative Example 4, it can be seen that using a microwave dryer to dry the liquid material can prevent the lithium citrate solution and titanium dioxide from stratification or sedimentation due to excessive drying time, ensure uniform dispersion of the material and improve drying efficiency.

[0175] From the comparison between Example 1 and Comparative Examples 5 to 6, it can be seen that the present application adopts a push-plate kiln for sintering. The temperature range of the push-plate kiln is divided into four zones: a heating zone, a high-temperature reaction zone, a medium-temperature reaction zone, and a cooling zone. The residence time in the high-temperature reaction zone is short, and each segment is indispensable, which solves the problem of low product performance caused by improper sintering process in the sintering process.

[0176] Test Example 2

[0177] Lithium ion extraction test in brine

[0178] Test samples: finished products of titanium-based lithium ion sieves prepared in Examples 1 to 16, and finished products of titanium-based lithium ion sieves prepared in Comparative Examples 1 to 7;

[0179] The test method is as follows: the titanium-based lithium ion sieve β-Li2TiO3 produced above is acidified with a 0.5M hydrochloric acid solution to obtain β-Li2TiO3, 2g of β-Li2TiO3 is placed in 1L of real brine for adsorption for 10 hours, and then the powder is filtered to obtain a filter cake, and then the filter cake is placed in 1L of 0.5M hydrochloric acid solution for decomposition for 3 hours to obtain a decomposition solution, and the concentration of potassium, sodium, magnesium, calcium and lithium ions in the decomposition solution is sampled and tested;

[0180] The specific test results are shown in Table 2 and Table 3 below:

[0181] Table 2

[0182] Table 3

[0183] It can be seen from the test results in Table 2 and Table 3 that the titanium-based lithium ion sieve produced by the patent application has extremely high selectivity for lithium ions, can selectively extract lithium ions from brine, and basically does not adsorb potassium, sodium, magnesium, and calcium ions, so that the ratio of lithium ions to sodium, potassium, magnesium, and calcium ions in the analytical solution is very high, that is, a high-quality lithium extraction analytical solution is obtained, which realizes the selective extraction of lithium ions from brine.

[0184] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application. Industrial Applicability

[0185] The present application provides a method for preparing a titanium-based lithium ion sieve, products prepared thereby, and applications thereof, relating to the field of lithium ion adsorption technology. The method for preparing the titanium-based lithium ion sieve comprises the following steps: mixing a water-soluble lithium source, a titanium source, and a viscosity enhancer, and sequentially ball milling and sand milling the mixture to obtain a mixed slurry of the lithium source and the titanium source; drying the mixed slurry and then crushing it to obtain a material to be calcined; calcining the material to be calcined at high temperature using a segmented method and then crushing it to obtain a titanium-based lithium ion sieve; the temperature range of the high-temperature calcination is divided into four zones, including a heating zone, a high-temperature reaction zone, a medium-temperature reaction zone, and a cooling zone. The present application aims to solve the problem of uneven and low performance of titanium-based lithium ion sieves during large-scale preparation.

[0186] Furthermore, it is understood that the preparation method of the titanium-based lithium ion sieve of the present application, the products and applications thereof are reproducible and can be used in a variety of industrial applications. For example, the preparation method of the titanium-based lithium ion sieve of the present application, the products and applications thereof can be used in the field of lithium ion adsorption technology.

Claims

1. A method for preparing a titanium-based lithium ion sieve, wherein: The preparation method of the titanium-based lithium ion sieve comprises the following steps: (1) mixing a water-soluble lithium source, a titanium source and a tackifier, and sequentially performing ball milling and sand milling to obtain a mixed slurry of the lithium source and the titanium source; (2) drying and then crushing the mixed slurry obtained in step (1) to obtain a material to be calcined; (3) calcining the material to be calcined obtained in step (2) at high temperature by a staged method and then crushing it to obtain a titanium-based lithium ion sieve; The temperature range of the high-temperature calcination is divided into four zones, including a heating zone, a high-temperature reaction zone, a medium-temperature reaction zone and a cooling zone; wherein the temperature of the heating zone is set to 100-750°C, the temperature of the high-temperature reaction zone is set to 950-1050°C, the temperature of the medium-temperature reaction zone is set to 800-900°C, and the temperature of the cooling zone is set to 150-650°C.

2. The method for preparing the titanium-based lithium ion sieve according to claim 1, wherein: In step (1), the mass ratio of the water-soluble lithium source, the titanium source and the viscosity enhancer is (1-5):(1-5):(0.01-0.05); Optionally, the water-soluble lithium source is a lithium citrate solution and / or a lithium oxalate solution; Optionally, the water-soluble lithium source is prepared by the following method: adding lithium hydroxide to water under stirring, then adding acid, and stirring to obtain a water-soluble lithium source solution; Optionally, the mass ratio of water, lithium hydroxide and acid is (3-5):(1.5-2):(3.5-4.5); Optionally, the acid comprises citric acid and / or oxalic acid.

3. The method for preparing the titanium-based lithium ion sieve according to claim 2, wherein: The lithium citrate solution is prepared by the following steps: deionized water is added into a stirring device, lithium hydroxide powder is added while stirring, and citric acid powder is added, and the mixture is stirred at a speed of 100 to 600 rpm for 1 to 3 hours to obtain the lithium citrate solution.

4. The method for preparing the titanium-based lithium ion sieve according to claim 2 or 3, wherein: The lithium oxalate solution is prepared by the following steps: deionized water is added into a stirring device, lithium hydroxide powder is added while stirring, and dihydrate oxalic acid powder is added, and the mixture is stirred at a speed of 100 to 600 rpm for 1 to 3 hours to obtain the lithium oxalate solution.

5. The method for preparing a titanium-based lithium ion sieve according to any one of claims 1 to 4, wherein: In step (1), the titanium source includes rutile titanium dioxide and / or anatase titanium dioxide; Optionally, in step (1), the particle size of the titanium source is 50 to 500 nm.

6. The method for preparing a titanium-based lithium ion sieve according to any one of claims 1 to 5, wherein: In step (1), the viscosity enhancer includes any one of polyethylene glycol, povidone, polyvinyl alcohol or hydroxyethyl cellulose or a combination of at least two thereof, and is optionally polyethylene glycol; Optionally, the number average molecular weight of the polyethylene glycol is 200-800, further optionally 400-600.

7. The method for preparing a titanium-based lithium ion sieve according to any one of claims 1 to 6, wherein: In step (1), the lithium source, titanium source and tackifier are mixed at a speed of 100 to 600 rpm and for a mixing time of 2 to 4 hours; Optionally, in step (1), the ball mill uses zirconium dioxide balls with a diameter of 2 to 8 mm, the ball milling speed is 30 to 90 rpm, and the ball milling time is 3 to 5 h; Optionally, in step (1), after the ball milling, the feed liquid needs to be fed into a sand mill in one direction at a feed rate of 10 to 20 L / min for grinding; Optionally, in step (1), the rotation speed of the sand mill is 500 to 1000 rpm, and the number of sand milling is 5 to 10 times.

8. The method for preparing a titanium-based lithium ion sieve according to any one of claims 1 to 7, wherein: In step (2), the drying is microwave drying; Optionally, in step (2), the feed rate of the mixed slurry to microwave drying is 80-100 kg / h; Optionally, the microwave drying power is 100-200 kW, and the microwave drying time is 0.5-1 h; Optionally, in step (2), the moisture content of the material to be calcined is 0.1-0.5%; Optionally, in step (2), the crushing is followed by sieving, and further optionally, the sieving is performed through a 50-100 mesh sieve.

9. The method for preparing a titanium-based lithium ion sieve according to any one of claims 1 to 8, wherein: In step (3), a push plate kiln is used for high temperature calcination and then crushing to obtain a titanium-based lithium ion sieve; Optionally, in step (3), the total length of the push plate kiln is 28 to 42 m; Optionally, in step (3), the heating zone is divided into 5 sections, each section is 2 to 3 m long, the temperature settings of the 5 heating zones are 100 to 150° C., 250 to 300° C., 400 to 450° C., 550 to 600° C., and 700 to 750° C., respectively, and the total residence time of the material in the heating zone is 4 to 5 h; Optionally, in step (3), the high temperature reaction zone is 1 section with a section length of 2 to 3 m, the temperature of the high temperature reaction zone is set to 950 to 1050° C., and the residence time of the material in the high temperature reaction zone is 0.8 to 1 h; Optionally, in step (3), the medium temperature reaction zone is divided into four sections, each section is 2 to 3 m long, and the temperature settings of the four medium temperature reaction zones are 800 to 900° C., 800 to 900° C., 800 to 900° C., 800 to 900° C., and 800 to 900° C., respectively, and the residence time of the material in the medium temperature reaction zone is 3.2 to 4 h; Optionally, in step (3), the cooling zone is divided into four sections, each section is 2 to 3 m long, the temperature settings of the four cooling zones are 600 to 650°C, 450 to 500°C, 300 to 350°C, and 150 to 200°C, respectively, and the residence time of the material in the cooling zone is 3.2 to 4 h.

10. The method for preparing a titanium-based lithium ion sieve according to any one of claims 1 to 9, wherein: In step (3), the pulverized product needs to be sieved, optionally through a 100-200 mesh sieve.

11. A titanium-based lithium ion sieve, wherein: The titanium-based lithium ion sieve is prepared by the preparation method of the titanium-based lithium ion sieve according to any one of claims 1 to 10.

12. Use of the titanium-based lithium ion sieve as claimed in claim 9 in selectively identifying and / or extracting lithium ions from brine.

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