Application of titanium black in preparation of titanium lithium adsorbent, titanium lithium adsorbent as well as preparation method and application of titanium lithium adsorbent

Abstract

The invention provides application of titanium black in preparation of a titanium-based lithium adsorbent, the titanium-based lithium adsorbent as well as a preparation method and application of the titanium-based lithium adsorbent, and particularly relates to the technical field of lithium adsorbents. The chemical formula of the titanium black is Ti4O7, and the titanium black has a sodium chloride type cubic crystal form and a rutile type tetragonal crystal form. Titanium black (Ti4O7) with a sodium chloride type cubic crystal form and a rutile type tetragonal crystal form is adopted as a titanium source, and the valence states of titanium in the Ti4O7 comprise positive trivalence (Ti < 3 + >) and positive tetravalence (Ti < 4 + >). Due to the existence of the two valence states, the titanium black has the structural characteristics of a sodium chloride type cubic crystal form and a rutile type tetragonal crystal form at the same time. The unique crystal structure provides two different occupied sites for lithium ions, and the number of adsorption sites of the lithium ions is increased. In addition, due to existence of the positive trivalent titanium ions, rapid migration of lithium ions in crystal lattices of the titanium-based lithium adsorbent can be promoted, and therefore the adsorption rate of the titanium-based lithium adsorbent is effectively increased.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium adsorbents, and in particular to the application of titanium black in the preparation of titanium-based lithium adsorbents, titanium-based lithium adsorbents, and their preparation methods and applications. Background Art

[0002] In engineering applications, the adsorption rate of the titanium-based lithium adsorbent β-H2TiO3 is relatively slow. During an adsorption time of 3 hours, its adsorption capacity is only 14 mg / g, while its theoretical saturated adsorption capacity is 143 mg / g, which means that the actual adsorption capacity only reaches 10% of the theoretical value. Therefore, 90% of the adsorption sites are not utilized, which severely limits the popularization and application of titanium-based lithium adsorbents.

[0003] The reason for the low adsorption rate of titanium-based lithium adsorbents is that the migration rate of lithium ions in their crystal structures is relatively slow. By using different raw materials to synthesize titanium-based lithium adsorbents, products with different microscopic crystal structures can be obtained, and these differences will lead to different adsorption rates of lithium ions.

[0004] Currently, the research on titanium sources mainly focuses on single or combined titanium sources such as metatitanic acid, anatase titanium dioxide, rutile titanium dioxide, and titanium tetrahydroxide. However, the adsorption rates of titanium-based lithium adsorbents synthesized using these titanium sources are still very low, and there has been no substantial improvement.

[0005] In view of this, the present invention is specifically proposed. Summary of the Invention

[0006] The purpose of the present invention is to provide the application of titanium black in the preparation of titanium-based lithium adsorbents, titanium-based lithium adsorbents, and their preparation methods and applications, aiming to solve at least one of the above technical problems in the prior art.

[0007] In order to achieve the above object of the present invention, the following technical solutions are specifically adopted: The first aspect of the present invention provides an application of titanium black in the preparation of titanium-based lithium adsorbents. The chemical formula of the titanium black is Ti4O7, which has a sodium chloride-type cubic crystal form and a rutile-type tetragonal crystal form.

[0008] Further, the chemical formula of the titanium-based lithium adsorbent is β-H2TiO3.

[0009] The second aspect of the present invention provides a preparation method of a titanium-based lithium adsorbent, including the following steps: after uniformly mixing a lithium source and a titanium source, adding a composite binder and deionized water, and performing kneading treatment; then, through extrusion molding, low-temperature roasting, and high-temperature calcination, a titanium-based lithium adsorbent precursor β-Li2TiO3 is obtained; acidifying the titanium-based lithium adsorbent precursor β-Li2TiO3 to obtain a titanium-based lithium adsorbent β-H2TiO3; wherein, the titanium source is titanium black.

[0010] Furthermore, the lithium source is a soluble lithium source and decomposes to generate gas during the calcination process.

[0011] Preferably, the lithium source includes at least one of lithium nitrate, lithium carbonate, and lithium citrate.

[0012] Preferably, the composite binder includes polyethylene glycol and lubricating oil.

[0013] Preferably, the molecular weight of the polyethylene glycol is 200 - 500.

[0014] Preferably, the lubricating oil is composed of three elements: C, H, and O.

[0015] Preferably, the lubricating oil includes glycerol and / or vegetable oil.

[0016] Preferably, the vegetable oil includes at least one of soybean oil, rapeseed oil, peanut oil, and corn oil.

[0017] Furthermore, the molar ratio of Li in the lithium source to Ti in the titanium source is 1.67 - 2.13:1.

[0018] Preferably, in the composite binder, the mass ratio of polyethylene glycol to lubricating oil is 2 - 4:1 - 3.

[0019] Preferably, the addition amount of the composite binder is 10 - 20% of the total mass of the lithium source and the titanium source.

[0020] Furthermore, the rotation speed of the kneading treatment is 20 - 40 rpm, and the time is 10 - 30 min.

[0021] Preferably, the length of the extruded material is 1 - 3 cm, and the diameter is 1 - 3 mm.

[0022] Preferably, the temperature of the low-temperature roasting is 80 - 150 °C, and the time is 1 - 3 h.

[0023] Furthermore, during high-temperature roasting, the loading thickness of the extruded material is 8 - 12 cm.

[0024] Preferably, the temperature of the high-temperature calcination is 950 - 1100 °C, and the time is 0.3 - 1 h.

[0025] The third aspect of the present invention provides a titanium-based lithium adsorbent prepared by the above preparation method.

[0026] Furthermore, the particle size of the titanium-based lithium adsorbent is 100 - 500 nm.

[0027] The fourth aspect of the present invention provides the application of the described titanium-based lithium adsorbent in extracting lithium from salt lakes or lithium recovery.

[0028] Compared with the prior art, the present invention has at least the following beneficial effects: The present invention uses titanium black (Ti4O7) with a sodium chloride-type cubic crystal form and a rutile-type tetragonal crystal form as the titanium source. The valence states of titanium in Ti4O7 include trivalent titanium (Ti 3+ ) and tetravalent titanium (Ti 4+ ). The existence of these two valence states enables titanium black to simultaneously possess the structural characteristics of a sodium chloride-type cubic crystal form and a rutile-type tetragonal crystal form. This unique crystal structure provides two different occupancy sites for lithium ions, increasing the number of lithium ion adsorption sites. In addition, the presence of trivalent titanium ions can promote the rapid migration of lithium ions in the lattice of the titanium-based lithium adsorbent, thereby effectively improving the adsorption rate of the titanium-based lithium adsorbent.

[0029] For the preparation method of the titanium-based lithium adsorbent provided by the present invention, kneading the raw materials and then extruding them into a mold is beneficial to make the powder combine more tightly, reduce the migration distance of the lithium source to the titanium source during the calcination process, facilitate improving the synthesis efficiency, shortening the high-temperature calcination time, improving the synthesis efficiency and reducing energy consumption.

[0030] The titanium-based lithium adsorbent provided by the present invention has a particle size of only 100 - 500 nm, a high specific surface area, an adsorption capacity of at least 116 mg / g within 3 h, reaching 81% of the theoretical saturated adsorption capacity, greatly improving the adsorption rate of the titanium-based lithium adsorbent and solving the technical problem of the low adsorption rate of the titanium-based lithium adsorbent.

[0031] Regarding the application of the titanium-based lithium adsorbent provided by the present invention, due to the above-mentioned advantages of the titanium-based lithium adsorbent, the efficiency of lithium adsorption is effectively improved, the duration of the lithium adsorption process is significantly shortened, providing strong support for the development of downstream industries and promoting technological progress and industrial upgrading in related fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0033] Figure 1 It is the process route diagram of the preparation method for Example 1; Figure 2 It is the scanning electron microscope image of the titanium-based lithium adsorbent precursor β-Li2TiO3 obtained in Example 1; Figure 3SEM image of the titanium-based lithium adsorbent precursor β-Li2TiO3 obtained in Example 2; Figure 4 SEM image of the titanium-based lithium adsorbent precursor β-Li2TiO3 obtained in Example 3; Figure 5 XRD pattern of the titanium-based lithium adsorbent precursor β-Li2TiO3 obtained in Example 1; Figure 6 XRD pattern of the titanium-based lithium adsorbent precursor β-Li2TiO3 obtained in Example 2; Figure 7 XRD pattern of the titanium-based lithium adsorbent precursor β-Li2TiO3 obtained in Example 3. Detailed implementation manners

[0034] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0035] In the following text, the terms "comprising", "having" and their cognates that can be used in various embodiments of the present invention are only intended to represent specific features, numbers, steps, operations, elements, components or combinations of the foregoing items, and should not be construed as first excluding the existence of one or more other features, numbers, steps, operations, elements, components or combinations of the foregoing items or increasing the possibility of one or more features, numbers, steps, operations, elements, components or combinations of the foregoing items.

[0036] The first aspect of the present invention provides an application of titanium black in the preparation of a titanium-based lithium adsorbent. The chemical formula of the titanium black is Ti4O7, which has a sodium chloride-type cubic crystal form and a rutile-type tetragonal crystal form.

[0037] The present invention uses titanium black (Ti4O7) with a sodium chloride-type cubic crystal form and a rutile-type tetragonal crystal form as a titanium source. The valence states of titanium in Ti4O7 include trivalent (Ti 3+ ) and tetravalent (Ti 4+ ). The existence of these two valence states enables titanium black to simultaneously possess the structural characteristics of a sodium chloride-type cubic crystal form and a rutile-type tetragonal crystal form. This unique crystal structure provides two different occupation sites for lithium ions, increasing the number of lithium ion adsorption sites. In addition, the presence of trivalent titanium ions can promote the rapid migration of lithium ions in the lattice of the titanium-based lithium adsorbent, thereby effectively improving the adsorption rate of the titanium-based lithium adsorbent.

[0038] Further, the chemical formula of the titanium-based lithium adsorbent is β-H2TiO3.

[0039] The second aspect of the present invention provides a method for preparing a titanium-based lithium adsorbent, comprising the following steps: after uniformly mixing a lithium source and a titanium source, adding a composite binder and deionized water, and performing kneading treatment; then, through extrusion molding, low-temperature calcination and high-temperature roasting, a titanium-based lithium adsorbent precursor β-Li2TiO3 is obtained; acidifying the titanium-based lithium adsorbent precursor β-Li2TiO3 to obtain a titanium-based lithium adsorbent β-H2TiO3; wherein, the titanium source is titanium black.

[0040] In the method for preparing a titanium-based lithium adsorbent provided by the present invention, kneading the raw materials and then extruding and molding are beneficial to making the powder combine more tightly, reducing the migration distance of the lithium source to the titanium source during the calcination process, facilitating the improvement of the synthesis efficiency, shortening the high-temperature calcination time, improving the synthesis efficiency and reducing the energy consumption.

[0041] Furthermore, the lithium source is a soluble lithium source and decomposes to generate gas during the calcination process. Such a lithium source will not introduce impurities during the preparation process, which is beneficial to ensuring the purity of the titanium-based lithium adsorbent.

[0042] Preferably, the lithium source includes at least one of lithium nitrate, lithium carbonate and lithium citrate.

[0043] Preferably, the composite binder includes polyethylene glycol and lubricating oil.

[0044] Preferably, the molecular weight of the polyethylene glycol is 200-600. Polyethylene glycol within this molecular weight range has a moderate viscosity, can effectively wrap and disperse the raw materials, significantly improve the dispersion efficiency, and thus ensure the full reaction of the titanium source and the lithium source.

[0045] Preferably, the lubricating oil is composed of three elements C, H and O, and the lubricant can be completely removed by roasting or calcination without introducing impurities.

[0046] Preferably, the lubricating oil includes glycerol and / or vegetable oil.

[0047] Preferably, the vegetable oil includes at least one of soybean oil, rapeseed oil, peanut oil and corn oil.

[0048] Furthermore, the molar ratio of Li in the lithium source to Ti in the titanium source is 1.67~2.13:1.

[0049] Typically but not restrictively, the molar ratio of Li in the lithium source to Ti in the titanium source can be, for example, 1.67:1, 1.9:1, 2.0:1, 2.1:1 or 2.13:1, or can also be any value within the range of 1.67~2.13:1.

[0050] Preferably, in the composite binder, the mass ratio of polyethylene glycol to lubricating oil is 2~4:1~3.

[0051] Typical but non-limiting, in the composite binder, the mass ratio of polyethylene glycol to lubricating oil can be, for example, 2:1, 2:2, 2:3, 3:1, 3:2, 3:3, 4:1, 4:2 or 4:3, or can also be any value within the range of 2 - 4:1 - 3.

[0052] The present invention does not specifically limit the addition amount of deionized water, which is flexibly adjusted according to the actual dry-wet degree of the material during the extrusion molding process. By appropriately adding deionized water, the dry-wet degree of the material can be effectively adjusted to ensure the smooth progress of the extrusion molding process, while ensuring the quality and performance of the molded material. It should be noted that the addition amount of deionized water cannot be 0, and another function is to dissolve and convert the lithium source into an ionic form.

[0053] Preferably, the addition amount of the composite binder is 10 - 20% of the total mass of the lithium source and the titanium source. When the addition amount of the composite binder exceeds 20% of the total mass of the lithium source and the titanium source, it will cause excessive shrinkage during low-temperature roasting, resulting in cracking of the extrusion-molded material particles.

[0054] Typical but non-limiting, the addition amount of the composite binder can be, for example, 10%, 12%, 15%, 18% or 20% of the total mass of the lithium source and the titanium source, or can also be any value within the range of 10% - 20%.

[0055] Furthermore, the rotation speed of the kneading treatment is 20 - 40 rpm, and the time is 10 - 30 min.

[0056] Typical but non-limiting, the rotation speed of the kneading treatment can be, for example, 20 rpm, 25 rpm, 30 rpm, 35 rpm or 40 rpm, or can also be any value within the range of 20 rpm - 40 rpm; the time of the kneading treatment can be, for example, 10 min, 15 min, 20 min, 25 min or 30 min, or can also be any value within the range of 10 min - 30 min.

[0057] During the implementation process of the present invention, the material forms of the extrusion molding include but are not limited to various structures such as granular, cylindrical, tubular, spiral, etc. No matter which form is adopted, it is necessary to ensure that it has good particle gap connectivity during the roasting or high-temperature calcination process to promote the full volatilization of the composite binder and gas diffusion, thereby optimizing the heat conduction uniformity, improving the synthesis efficiency and reducing the energy consumption.

[0058] In one implementation manner of the present invention, the length of the extrusion-molded material is 1 - 3 cm, and the diameter is 1 - 3 mm.

[0059] Typically but not restrictively, the length of the extruded material can be, for example, 1 cm, 1.5 cm, 2 cm, 2.5 cm or 3 cm, or any value within the range of 1 cm - 3 cm; the diameter of the extruded material can be, for example, 1 mm, 1.5 mm, 2 mm, 2.5 mm or 3 mm, or any value within the range of 1 mm - 3 mm.

[0060] Using the material with a length of 1 - 3 cm as the material for high-temperature calcination instead of the powder mixture of lithium source and titanium source as the material for high-temperature calcination, due to the formation of a crisscross stacking arrangement between the materials, there are certain gaps between the materials, and the thermal radiation can penetrate from top to bottom and from all around to the center, enabling uniform heating reaction of all the materials in the sagger with a thickness of 8 - 12 cm, making the product performance uniform and stable.

[0061] Preferably, the temperature of the low-temperature roasting is 80 - 150 °C and the time is 1 - 3 h.

[0062] Typically but not restrictively, the temperature of the low-temperature roasting can be, for example, 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, 130 °C, 140 °C or 150 °C, or any value within the range of 80 °C - 150 °C; the time of the low-temperature roasting can be, for example, 1 h, 1.5 h, 2 h, 2.5 h or 3 h, or any value within the range of 1 h - 3 h.

[0063] Furthermore, during high-temperature calcination, the loading thickness of the extruded material is 8 - 12 cm.

[0064] When the powder raw material is loaded in the sagger with a depth of 8 - 12 cm, it is difficult for the thermal radiation during high-temperature calcination to achieve uniform radiation of all the powder materials, which will lead to non-uniform performance of the calcined product. While using the extruded material as the material for high-temperature calcination can achieve uniform heating.

[0065] Typically but not restrictively, during high-temperature calcination, the loading thickness of the extruded material can be, for example, 8 cm, 9 cm, 10 cm, 11 cm or 12 cm, or any value within the range of 8 cm - 12 cm.

[0066] Preferably, the temperature of the high-temperature calcination is 950 - 1100 °C and the time is 0.3 - 1 h.

[0067] Typically but not limited thereto, the temperature of the high-temperature calcination can be, for example, 950°C, 975°C, 1000°C, 1025°C, 1050°C, 1075°C or 1100°C, or can be any value within the range of 950°C - 1100°C; the time of the high-temperature calcination can be, for example, 0.3h, 0.4h, 0.5h, 0.6h, 0.7h, 0.8h, 0.9h or 1h, or can be any value within the range of 0.3h - 1h.

[0068] The third aspect of the present invention provides a titanium-based lithium adsorbent prepared by the above-mentioned preparation method.

[0069] The titanium-based lithium adsorbent provided by the present invention has a particle size of only 100 - 500 nm, has a high specific surface area, and the adsorption capacity within 3 h is at least 116 mg / g, reaching 81% of the theoretical saturated adsorption capacity, greatly improving the adsorption rate of the titanium-based lithium adsorbent and solving the technical problem of the low adsorption rate of the titanium-based lithium adsorbent.

[0070] Further, the particle size of the titanium-based lithium adsorbent is 100 - 500 nm.

[0071] The fourth aspect of the present invention provides the application of the above-mentioned titanium-based lithium adsorbent in lithium extraction from salt lakes or lithium recovery.

[0072] Due to the advantages of the titanium-based lithium adsorbent provided by the present invention, the efficiency of lithium adsorption is effectively improved, the duration of the lithium adsorption process is significantly shortened, providing strong support for the development of downstream industries and promoting the technological progress and industrial upgrading of related fields.

[0073] The present invention will be further illustrated below through specific examples and comparative examples. However, it should be understood that these examples are only for more detailed illustration and should not be construed as limiting the present invention in any way. For the raw materials used in the examples and comparative examples of the present invention, without specifying specific conditions, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments whose manufacturers are not specified, they are all conventional products that can be obtained through commercial purchase.

[0074] Example 1 This example provides a titanium-based lithium adsorbent, and the preparation method is as Figure 1 shown, specifically as follows: 1. Add 5 kg of LiNO3 powder, 3 kg of Li2CO3 powder, and 7 kg of Ti4O7 powder into a kneader with a volume of 40 L, and mix for 30 min at a stirring speed of 20 revolutions per minute. After the materials are mixed evenly, they are ready for use.

[0075] 2. Add 1 kg of PEG-400, 0.5 kg of glycerol, and then 2 kg of deionized water to the above uniformly mixed lithium source and titanium source, and knead for 10 min at a stirring speed of 20 rpm.

[0076] 3. Transfer the kneaded material to a horizontal extruder and extrude the material into strips with a diameter of 1 mm and a length of 1 - 3 cm.

[0077] 4. Place the above strips in an oven at 80 °C for low-temperature baking for 1 h, and then cool to room temperature after taking them out.

[0078] 5. Load the above low-temperature baked material into a mullite crucible with a volume of 15 L, with a loading thickness of 8 cm. Transfer the crucible to a muffle furnace, and the calcination temperature in the high-temperature section is 950 °C, and the calcination time is 0.3 h. Cool to room temperature to obtain the titanium-based lithium adsorbent precursor β-Li2TiO3, and obtain the titanium-based lithium adsorbent β-H2TiO3 after acidification with 1 M hydrochloric acid solution.

[0079] Example 2 This example provides a titanium-based lithium adsorbent, and the specific preparation method is as follows: 1. Add 8 kg of LiNO3 powder, 4 kg of Li2CO3 powder, and 8 kg of Ti4O7 powder to a kneader with a volume of 40 L, and mix for 90 min at a stirring speed of 40 rpm. After the materials are mixed evenly, set aside for use.

[0080] 2. Add 2 kg of PEG-400, 1.5 kg of glycerol, and then 4 kg of deionized water to the above uniformly mixed lithium source and titanium source, and knead for 30 min at a stirring speed of 40 rpm.

[0081] 3. Transfer the kneaded material to a horizontal extruder and extrude the material into strips with a diameter of 3 mm and a length of 1 - 3 cm.

[0082] 4. Place the above strips in an oven at 150 °C for low-temperature baking for 3 h, and then cool to room temperature after taking them out.

[0083] 5. Load the above low-temperature baked material into a mullite crucible with a volume of 15 L, with a loading thickness of 12 cm. Transfer the crucible to a muffle furnace, and the calcination temperature in the high-temperature section is 1100 °C, and the calcination time is 1 h. Cool to room temperature to obtain the titanium-based lithium adsorbent precursor β-Li2TiO3, and obtain the titanium-based lithium adsorbent β-H2TiO3 after acidification with 1 M hydrochloric acid solution.

[0084] Example 3 This example provides a titanium-based lithium adsorbent, and the specific preparation method is as follows: 1. In a kneader with a volume of 40 L, add 6.5 kg of LiNO3 powder, 3.5 kg of Li2CO3 powder, and 7.5 kg of Ti4O7 powder. Mix at a stirring speed of 30 revolutions per minute for 60 minutes. After the materials are mixed evenly, set them aside for use.

[0085] 2. In the above-mentioned evenly mixed lithium source and titanium source, add 1.5 kg of PEG-400, 1 kg of glycerol, and then add 3 kg of deionized water. Knead at a stirring speed of 30 revolutions per minute for 20 minutes.

[0086] 3. Transfer the kneaded materials to a horizontal extrusion machine and extrude the materials into strip-shaped objects with a diameter of 2 mm and a length of 1 - 3 cm.

[0087] 4. Place the above strip-shaped objects in an oven at 115 °C for low-temperature baking for 2 h. After taking them out, cool them down to room temperature.

[0088] 5. Load the materials baked at low temperature above into a mullite crucible with a volume of 15 L, and the loading thickness is 10 cm. Transfer the crucible to a muffle furnace. The calcination temperature in the high-temperature section is 1025 °C, and the calcination time is 0.65 h. Cool down to room temperature to obtain the titanium-based lithium adsorbent precursor β-Li2TiO3, and obtain the titanium-based lithium adsorbent β-H2TiO3 after acidification with 1 M hydrochloric acid solution.

[0089] Example 4 This example provides a titanium-based lithium adsorbent. Different from Example 1, Li2CO3 is not added, and the mass of LiNO3 powder is adjusted to 10.59 kg. The remaining preparation steps are the same as those in Example 1 and will not be elaborated here.

[0090] Example 5 This example provides a titanium-based lithium adsorbent. Different from Example 1, LiNO3 is not added, and the mass of Li2CO3 powder is adjusted to 5.68 kg. The remaining preparation steps are the same as those in Example 1 and will not be elaborated here.

[0091] Example 6 This example provides a titanium-based lithium adsorbent. Different from Example 1, 10.76 kg of lithium citrate (C6H5Li3O7) is used to replace lithium nitrate and lithium carbonate. The remaining raw materials and preparation methods are the same as those in Example 1 and will not be elaborated here.

[0092] Example 7 This example provides a titanium-based lithium adsorbent. Different from Example 1, in step 3, the materials are extruded into granular shapes with a particle size of 5 mm. The remaining raw materials and preparation methods are the same as those in Example 1 and will not be elaborated here.

[0093] Comparative Example 1 This comparative example provides a titanium-based lithium adsorbent, and the specific preparation method is as follows: 1. In a kneader with a volume of 40 L, add 5 kg of LiNO3 powder, 3 kg of Li2CO3 powder, and 10 kg of amorphous metatitanic acid H2TiO3 powder. Mix at a stirring speed of 20 revolutions per minute for 60 minutes. After the materials are mixed evenly, set aside for use.

[0094] The preparation processes of Steps 2 to 5 are the same as those in the corresponding steps of Example 1.

[0095] Comparative Example 2 This comparative example provides a titanium-based lithium adsorbent, and the specific preparation method is as follows: 1. In a kneader with a volume of 40 L, add 5 kg of LiNO3 powder, 3 kg of Li2CO3 powder, and 8 kg of anatase TiO2 powder. Mix at a stirring speed of 20 revolutions per minute for 30 minutes. After the materials are mixed evenly, set aside for use.

[0096] The preparation processes of Steps 2 to 5 are the same as those in the corresponding steps of Example 1.

[0097] Comparative Example 3 This comparative example provides a titanium-based lithium adsorbent, and the specific preparation method is as follows: 1. In a kneader with a volume of 40 L, add 5 kg of LiNO3 powder, 3 kg of Li2CO3 powder, and 8 kg of rutile TiO2 powder. Mix at a stirring speed of 20 revolutions per minute for 30 minutes. After the materials are mixed evenly, set aside for use.

[0098] The preparation processes of Steps 2 to 5 are the same as those in the corresponding steps of Example 1.

[0099] Comparative Example 4 This comparative example provides a titanium-based lithium adsorbent, and the specific preparation method is as follows: 1. In a kneader with a volume of 40 L, add 5 kg of LiNO3 powder, 3 kg of Li2CO3 powder, and 12 kg of amorphous Ti(OH)4 powder. Mix at a stirring speed of 20 revolutions per minute for 30 minutes. After the materials are mixed evenly, set aside for use.

[0100] The preparation processes of Steps 2 to 5 are the same as those in the corresponding steps of Example 1.

[0101] Comparative Example 5 This comparative example provides a titanium-based lithium adsorbent. Different from Example 1, Steps 2, 3, and 4 are omitted, and the materials are directly subjected to high-temperature calcination after mixing.

[0102] Comparative Example 6 This comparative example provides a titanium-based lithium adsorbent. Different from Example 1, in step 2, glycerol is omitted, and the mass of PEG-400 is adjusted to 1.5 kg. The remaining principles and preparation methods are the same as those in Example 1, and will not be elaborated here.

[0103] Comparative Example 7 This comparative example provides a titanium-based lithium adsorbent. Different from Example 1, in step 2, PEG-400 is omitted, and the mass of glycerol is adjusted to 1.5 kg. The remaining principles and preparation methods are the same as those in Example 1, and will not be elaborated here.

[0104] Comparative Example 8 This comparative example provides a titanium-based lithium adsorbent. Different from Example 1, in step 2, deionized water is omitted. The remaining principles and preparation methods are the same as those in Example 1, and will not be elaborated here.

[0105] Characterization Example 1 The titanium-based lithium adsorbent precursors β-Li2TiO3 obtained in Examples 1-3 were subjected to scanning electron microscopy, and the corresponding scanning electron micrographs are as Figure 2 、 Figure 3 and Figure 4 shown.

[0106] From Figure 2 、 Figure 3 and Figure 4 it can be seen that the synthesized β-Li2TiO3 has a particle size of 100-500 nm, which is very small and is beneficial to improving the adsorption capacity of the titanium-based lithium adsorbent.

[0107] Characterization Example 2 The titanium-based lithium adsorbent precursors β-Li2TiO3 obtained in Examples 1-3 were subjected to XRD, and the corresponding XRD patterns are as Figure 5 、 Figure 6 and Figure 7 shown.

[0108] From Figure 5 、 Figure 6 and Figure 7 it can be seen that the crystal form of the synthesized titanium-based lithium adsorbent precursor is the β-Li2TiO3 crystal form, which proves that the crystal form of the titanium-based lithium ion sieve synthesized in Examples 1-3 is single and there are no other impurities.

[0109] Test Example 1 g of the titanium-based lithium adsorbent β-H2TiO3 obtained in the examples and comparative examples was placed in 2 L of real brine (lithium ion concentration was 250 mg / L) for adsorption for 3 h. The samples were taken to test the lithium ion concentration in the adsorption solution, and the lithium adsorption capacity was calculated. The lithium adsorption capacity measured after 3 h of adsorption is shown in Table 1.

[0110] Table 1

[0111] As can be seen from Table 1, after the titanium sources of Comparative Examples 1-4 are amorphous metatitanic acid, anatase TiO2, rutile TiO2, and amorphous Ti(OH)4 respectively, the lithium adsorption capacity of the synthesized titanium-based lithium adsorbent in 3 h is only 15-25 mg / g, which is only 10.5-17.5% of the theoretical saturated adsorption capacity (143 mg / g). It can be known that the adsorption rate of amorphous metatitanic acid, anatase TiO2, rutile TiO2, and amorphous Ti(OH)4 as titanium sources for synthesizing titanium-based lithium adsorbents is very slow and the adsorption capacity is very low.

[0112] As can be seen from Example 1 compared with Comparative Example 5, adopting the method of first shaping and then calcining the raw material powder instead of directly calcining after mixing the raw material powder is beneficial to making the raw material powder combine more tightly, reducing the migration distance of the lithium source to the titanium source during the calcination process, and facilitating the improvement of the synthesis efficiency. The calcination duration in the high-temperature stage of this synthesis only needs 0.3-1 h, greatly shortening the time required for high-temperature calcination, improving the synthesis efficiency and reducing energy consumption. Moreover, when the powder raw material is placed in a sagger with a depth of 8-12 cm, the thermal radiation during the high-temperature calcination can achieve uniform radiation of all powder materials. Using 1-3 cm strip-shaped materials as the materials for high-temperature calcination, due to the formation of a criss-cross stacking arrangement between the strip-shaped materials and there are certain gaps between the strip-shaped materials, the thermal radiation can penetrate from top to bottom and from all around to the center, and uniform heating reaction of all materials in the sagger with a thickness of 8-12 cm can be realized, making the product performance uniform and stable.

[0113] As can be seen from Example 1 compared with Comparative Example 6, when kneading and then extruding in the form of using PEG-400 as a single binder, the lithium adsorption capacity of the synthesized titanium-based lithium adsorbent in 3 h is 37 mg / g, which is 26% of the theoretical saturated adsorption capacity (143 mg / g). It can be known that the adsorption rate of kneading and then extruding to synthesize titanium-based lithium adsorbents in the form of using PEG-400 as a single binder is very slow and the adsorption capacity is very low. This is because the viscosity of the PEG-400 liquid is less than that of glycerol. When the viscosity of the binder is too high, it is not conducive to the uniform dispersion of the powder and the binder. Therefore, the introduction of PEG-400 can solve the problem of uneven dispersion of the powder and the binder caused by the too high viscosity of glycerol, and is conducive to the uniform dispersion of the powder and binder system; however, the lubricity of glycerol is higher than that of PEG-400. Due to the small holes and large resistance during extrusion, the strong lubricity of glycerol can make the extrusion more smooth.

[0114] It can be seen from Example 1 compared with Comparative Example 7 that when kneading and then extruding with glycerol as the single binder, the 3-hour lithium adsorption capacity of the synthesized titanium-based lithium adsorbent is 35 mg / g, which is 24.5% of the theoretical saturated adsorption capacity (143 mg / g). It can be known that the adsorption rate of the titanium-based lithium adsorbent synthesized by kneading and then extruding with glycerol as the single binder is very slow and the adsorption capacity is very low. The reason is that the viscosity of the PEG-400 liquid is less than that of glycerol. When the viscosity of the binder is too high, it is not conducive to the uniform dispersion of the powder and the binder. Therefore, the introduction of PEG-400 can solve the problem of uneven dispersion of the powder and the binder caused by the too high viscosity of glycerol, and is conducive to the uniform dispersion of the powder and the binder system.

[0115] It can be seen from Example 1 compared with Comparative Example 8 that when deionized water is not added in the raw material kneading process, the 3-hour lithium adsorption capacity of the synthesized titanium-based lithium adsorbent is 5.2 mg / g, which is 3.6% of the theoretical saturated adsorption capacity (143 mg / g). It can be known that the adsorption rate of the titanium-based lithium adsorbent synthesized without adding deionized water in the raw material kneading process is very slow and the adsorption capacity is very low. This is because adding deionized water can dissolve the soluble lithium source. After the lithium nitrate powder is dissolved, this part of the lithium source will infiltrate the titanium black Ti4O7 in the form of lithium ions, and the lithium ions will evenly cover the surface of the titanium black Ti4O7. During the high-temperature calcination process, this part of the lithium ions can quickly intercalate into the lattice of the titanium compound, which is beneficial to greatly shortening the calcination time and improving the synthesis rate.

[0116] The 3-hour lithium adsorption capacity of the titanium-based lithium adsorbent β-H2TiO3 prepared by the present invention is 116 - 123 mg / g, reaching 81 - 86% of the theoretical saturated adsorption capacity (143 mg / g). It can be seen that the titanium-based lithium adsorbent synthesized by the present invention has the advantages of high adsorption capacity and high adsorption rate.

[0117] Finally, it should be noted that the above embodiments are only specific embodiments of the present invention, used to illustrate the technical solutions of the present invention, rather than limiting them. The protection scope of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: any person skilled in the art within the technical scope disclosed by the present invention can still modify the technical solutions recorded in the foregoing embodiments or can easily think of changes, or perform equivalent replacements for some of the technical features; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. Application of titanium black in preparing titanium-based lithium adsorbent, characterized in that, The chemical formula of the titanium black is Ti4O7, which has a sodium chloride-type cubic crystal form and a rutile-type tetragonal crystal form.

2. The application according to claim 1, wherein The chemical formula of the titanium-based lithium adsorbent is β-H2TiO3.

3. A preparation method of a titanium-based lithium adsorbent, characterized in that, It includes the following steps: After uniformly mixing a lithium source and a titanium source, a composite binder and deionized water are added, and kneading treatment is carried out; then, extrusion molding, low-temperature calcination, and high-temperature calcination are carried out to obtain a precursor of the titanium-based lithium adsorbent, β-Li2TiO3; the precursor of the titanium-based lithium adsorbent, β-Li2TiO3, is acidified to obtain the titanium-based lithium adsorbent β-H2TiO3; Among them, the titanium source is titanium black.

4. The preparation method according to claim 3, characterized in that, The lithium source is a soluble lithium source and will decompose to produce gas during the calcination process; Preferably, the lithium source includes at least one of lithium nitrate, lithium carbonate, and lithium citrate; Preferably, the composite binder includes polyethylene glycol and lubricating oil; Preferably, the molecular weight of the polyethylene glycol is 200-600; Preferably, the lubricating oil is composed of three elements, C, H, and O; Preferably, the lubricating oil includes glycerol and / or vegetable oil; Preferably, the vegetable oil includes at least one of soybean oil, rapeseed oil, peanut oil, and corn oil.

5. The preparation method according to claim 3, characterized in that, The molar ratio of Li in the lithium source to Ti in the titanium source is 1.67-2.13:1; Preferably, in the composite binder, the mass ratio of polyethylene glycol to lubricating oil is 2-4:1-3; Preferably, the addition amount of the composite binder is 10-20% of the total mass of the lithium source and the titanium source.

6. The preparation method according to any one of claims 3 to 5, characterized in that, The rotation speed of the kneading treatment is 20-40 rpm, and the time is 10-30 min; Preferably, the length of the extruded material is 1-3 cm, and the diameter is 1-3 mm; Preferably, the temperature of the low-temperature calcination is 80-150 °C, and the time is 1-3 h.

7. The preparation method according to any one of claims 3 to 5, characterized in that, During high-temperature calcination, the loading thickness of the extruded material is 8-12 cm; Preferably, the temperature of the high-temperature calcination is 950-1100 °C, and the time is 0.3-1 h.

8. A titanium-based lithium adsorbent, characterized in that, It is prepared by using the preparation method described in any one of claims 3-7.

9. The titanium-based lithium adsorbent according to claim 8, wherein The particle size of the titanium-based lithium adsorbent is 100-500 nm.

10. Use of the titanium-based lithium adsorbent according to claim 9 in lithium extraction from salt lakes or lithium recovery.

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