Superfine TiO2 powder and preparation method thereof
By using a modified dispersant in the hydrolysis method of titanium tetrachloride, the problems of uneven particle size and poor dispersion of ultrafine TiO2 powder in the prior art were solved, and ultrafine TiO2 powder with uniform particle size and good dispersion were achieved. The system has improved product quality and production efficiency.
Patent Information
- Application Number
- CN202411509692.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-28
- Publication Date
- 2025-02-07
AI Technical Summary
The existing titanium tetrachloride hydrolysis method is difficult to obtain ultrafine TiO2 powder with uniform particle size, and the product is prone to agglomeration, poor dispersion, difficult to control crystal form and morphology, difficult to meet the needs of different application fields, low production efficiency, and difficult to achieve Large-scale production.
The modified dispersant is used to uniformly disperse and quickly hydrolyze during the hydrolysis of TiCl4. The modified dispersant is adsorbed on the surface of metatitanate colloids, limiting the growth and agglomeration of crystal nuclei, and accurately controlling the particle size and morphology of TiO2 particles.
Ultrafine TiO2 powder with uniform particle size, good dispersion and high spherical shape was obtained, which significantly improved product quality and performance stability, and had good repeatability and industrial production potential.
Smart Images
Figure CN119390114A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of titanium dioxide, and in particular to an ultrafine TiO2 powder and a preparation method thereof. Background Art
[0002] Titanium dioxide (TiO2) is an important inorganic functional material, which is widely used in many fields due to its unique physical and chemical properties. It has excellent optical properties, chemical stability, non-toxicity and harmlessness. Titanium dioxide has three main crystal forms: anatase, rutile and brookite, among which anatase and rutile are the most common and widely used. Rutile TiO2 has a higher refractive index and better weather resistance, while anatase TiO2 has higher photocatalytic activity.
[0003] Titanium dioxide is widely used in traditional industries, including: as a white pigment in the coating industry, providing excellent hiding power and whiteness; as a colorant and UV shielding agent in the plastics industry; as a paper industry to improve the opacity and whiteness of paper; as a sunscreen and pigment in the cosmetics industry; as a food additive as a colorant and anti-caking agent. At the same time, titanium dioxide also shows great potential in emerging fields, such as photocatalysis for environmental purification, self-cleaning materials and antibacterial materials; as a key material for dye-sensitized solar cells in solar cells; as a water treatment and air purification for environmental purification; as a sensor for gas sensing and biosensors; as a drug delivery and biocompatible materials in the medical field.
[0004] With the advancement of science and technology and the increase in application needs, ultrafine TiO2 powder has received more and more attention due to its special properties. Compared with ordinary TiO2, ultrafine TiO2 powder has a larger specific surface area, higher surface activity and better optical properties. These characteristics make it have unique application value in the fields of high-performance coatings, photocatalytic materials, new electronic components, etc. For example, in the field of photocatalysis, ultrafine TiO2 powder can significantly improve the catalytic efficiency; in solar cells, it can increase the transmission efficiency of electrons; in self-cleaning coatings, it can provide better hydrophobic and photocatalytic properties. In addition, ultrafine TiO2 powder also shows broad application prospects in emerging fields such as gas sensors and biomedical imaging.
[0005] At present, the preparation methods of high-purity titanium dioxide mainly include sulfate hydrolysis method, direct hydrolysis method of titanium tetrachloride, sulfuric acid method and chlorination method. Among them, the titanium tetrachloride hydrolysis method has attracted widespread attention due to its short process flow and high product purity. This method uses titanium tetrachloride as raw material and directly generates titanium dioxide through hydrolysis reaction. The main advantages of the titanium tetrachloride hydrolysis method include: high raw material purity, which can produce high-purity titanium dioxide; mild reaction conditions and low energy consumption; simple process flow and easy control. However, this method also has some challenges, such as high raw material cost, equipment is susceptible to corrosion, and pH value and temperature control during the reaction process have a great impact on product quality.
[0006] Although the titanium tetrachloride hydrolysis method has the above advantages, it still faces some problems in practical applications: it is difficult to control the particle size and it is difficult to obtain ultrafine powder with uniform particle size; the product is easy to agglomerate and has poor dispersibility; it is difficult to control the crystal form and morphology and it is difficult to meet the needs of different application fields; the production efficiency is low and it is difficult to achieve large-scale production.
[0007] Therefore, developing an improved process based on titanium tetrachloride hydrolysis to solve the above problems can not only ensure the high quality of the product, but also achieve large-scale production, which is of great significance for meeting the growing market demand and promoting the development of related industries. The present invention aims to solve the problems existing in the prior art and provide a novel method for preparing ultrafine TiO2 powder to obtain high-quality ultrafine TiO2 powder with uniform particle size, good dispersibility and controllable crystal form. Summary of the invention
[0008] In order to solve the deficiencies in the prior art, the purpose of the present invention is to provide an ultrafine TiO2 powder and a preparation method thereof, thereby obtaining an ultrafine TiO2 powder with uniform particle size, good dispersibility and high sphericity.
[0009] In order to achieve the above object, the present invention adopts the following technical solution:
[0010] A method for preparing ultrafine TiO2 powder comprises the following steps:
[0011] (1) Adding TiCl4 into deionized water to prepare a TiCl4 solution;
[0012] (2) adding the modified dispersant into deionized water to prepare a modified dispersant solution;
[0013] (3) adding the TiCl4 solution to the modified dispersant solution, preserving the solution for hydrolysis, and obtaining a titanic acid solution;
[0014] (4) naturally cooling the titanic acid solution for aging, and filtering to obtain a titanic acid filter cake;
[0015] (5) The titanic acid filter cake is placed in a sagger, sintered at high temperature, and crushed to obtain the ultrafine TiO2 powder.
[0016] Preferably, in step (1), the solution is prepared at 25-35° C., and the concentration of the TiCl 4 solution is 40-50 wt %.
[0017] Specifically, in step (1), the solution can be prepared at 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, or 35° C., and the concentration of the TiCl4 solution can be 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50 wt%.
[0018] Preferably, in step (2), the solution is prepared at 75-95° C., and the concentration of the modified dispersant solution is 0.2-1 wt %. A higher temperature is conducive to the dissolution of the modified dispersant.
[0019] Specifically, in step (2), the solution can be prepared at 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95°C; the concentration of the modified dispersant solution can be 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1 wt%.
[0020] Preferably, in step (3), the volume ratio of the TiCl4 solution to the modified dispersant solution is 1:1-2; and the heat preservation and hydrolysis conditions are stirring and heat preservation and hydrolysis at 80-100°C for 40-80 minutes.
[0021] Specifically, in step (3), the volume ratio of TiCl4 solution to modified dispersant solution can be 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2; the insulation hydrolysis temperature can be 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100°C; the insulation hydrolysis time can be 40, 45, 50, 55, 60, 65, 70, 75, 80min.
[0022] Preferably, in step (4), the temperature is naturally lowered to below 40° C., and the water content of the titanic acid filter cake is reduced to below 50% by pressure filtration.
[0023] Preferably, in step (5), the sintering conditions are sintering at 700-900° C. for 2-4 hours; and crushing with a jet mill to 160-200 mesh.
[0024] Specifically, in step (5), the sintering temperature can be 700, 710, 720, 730, 740, 750, 760, 770, 780, 790, 800, 810, 820, 830, 840, 850, 860, 870, 880, 890, 900°C; and the sintering time can be 2, 2.5, 3, 3.5, 4h.
[0025] Preferably, in step (2), the structural formula of the modified dispersant is as follows:
[0026]
[0027] Preferably, in step (2), the preparation method of the modified dispersant comprises the following steps: dissolving 2,4,6-triaminopyrimidine in DMSO, then adding 1,4-butane sultone, stirring and mixing evenly, introducing nitrogen to expel air, heating to react under a nitrogen atmosphere, and after the reaction is completed, pouring the product into ice water to promote precipitation, filtering, washing with cold water, and vacuum drying to obtain the modified dispersant.
[0028] Preparation of modified dispersant: The amino group on triaminopyrimidine acts as a nucleophilic agent to attack the electrophilic center of the lactone ring. Subsequently, the reaction is promoted and oxidation is prevented by stirring and mixing and passing nitrogen. Under elevated temperature conditions, the reaction is further accelerated, the lactone ring opens, a CN bond is formed, and a sulfonic acid group is generated. Since the substrate has three amino groups, mono-, di- or tri-substitution reactions may occur, and the degree of reaction depends on the reaction conditions and the amount of lactone used. After the reaction is completed, the product is poured into ice water to promote precipitation. This step also helps to quench the reaction and remove unreacted raw materials. Finally, the target product is obtained by filtration, cold water washing and vacuum drying. The whole process can be summarized by the following reaction formula (taking tri-substitution as an example): C4H7N4+3C4H8O3S→C 16 H 28 N4O9S3+3H2O.
[0029] Preferably, the usage ratio of 2,4,6-triaminopyrimidine, DMSO and 1,4-butane sultone is 1-1.5 g: 40-60 mL: 3.3-5.0 g.
[0030] Preferably, the stirring and mixing conditions are stirring at 20-30° C. for 1-3 h; the temperature rising reaction conditions are stirring and reacting at 45-65° C. for 4-7 h; and the drying conditions are vacuum drying at 40-60° C. for 4-6 h.
[0031] The present invention also claims protection for an ultrafine TiO2 powder prepared by the preparation method.
[0032] Compared with the prior art, the present invention has the following beneficial effects:
[0033] 1. The present invention provides a method for preparing ultrafine TiO2 powder. In the process of TiCl4 hydrolysis, a modified dispersant is used, which can effectively reduce the surface tension of the reaction system and promote the uniform dispersion and rapid hydrolysis of TiCl4. Secondly, the dispersant molecules can be adsorbed on the surface of the newly generated metatitanic acid colloid in time to limit the excessive growth and agglomeration of the crystal nucleus, thereby realizing the precise control of the particle size and morphology of the TiO2 particles. The present invention precisely controls the conditions of the hydrolysis, aging, sintering and other steps, and finally obtains ultrafine TiO2 powder with uniform particle size, good dispersibility and excellent optical properties, which not only significantly improves the product quality and performance stability, but also has good repeatability and industrial production potential, providing a new technical path for the large-scale production of high-quality TiO2 powder.
[0034] 2. The present invention provides a method for preparing a modified dispersant, using the amino group (-NH2) on 2,4,6-triaminopyrimidine as a nucleophilic reagent to attack the electrophilic center of 1,4-butane sultone, resulting in the opening of the lactone ring and the formation of a CN bond, while generating a sulfonic acid group (-SO3H). By introducing a side chain containing a sulfonic acid group on 2,4,6-triaminopyrimidine, its chemical and physical properties are changed, thereby obtaining a modified dispersant with a dispersing function.
[0035] 3. The present invention provides a modified dispersant, in which the nitrogen atoms in the molecular structure can form strong adsorption with the titanic acid particles through coordination, firmly anchoring the modified dispersant on the particle surface, effectively preventing the dispersant from being lost during subsequent treatment, thereby maintaining a stable and lasting dispersion effect. Secondly, after the sulfonic acid group (-SO3H) in the molecule dissociates in an aqueous solution, it can cause the surface of the titanic acid colloidal particles to be negatively charged, generating a strong electrostatic repulsion, effectively preventing the particles from approaching and aggregating, and significantly improving the stability of the dispersion system. In addition, the hydrophilic sulfonic acid group and the hydrophobic skeleton coexisting in the modified dispersant molecule give it excellent amphiphilicity, which can effectively reduce the surface energy of the TiO2 particles, further enhance the dispersion effect, and help prepare TiO2 powders with smaller particle size, more uniform distribution, and higher sphericity. BRIEF DESCRIPTION OF THE DRAWINGS
[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show schematic diagrams of certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.
[0037] Figure 1 This is the SEM image of the ultrafine TiO2 powder prepared in Example 1. DETAILED DESCRIPTION
[0038] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with embodiments. Of course, the specific embodiments described here are only used to explain the present invention and are not used to limit the present invention.
[0039] Unless otherwise specified, the chemical reagents and materials in the present invention are purchased from commercial sources or synthesized from raw materials purchased from commercial sources.
[0040] A method for preparing ultrafine TiO2 powder comprises the following steps:
[0041] (1) dissolving 1-1.5 g of 2,4,6-triaminopyrimidine in 40-60 mL of DMSO, then adding 3.3-5.0 g of 1,4-butane sultone, stirring at 20-30° C. for 1-3 h, introducing nitrogen to expel air, stirring and reacting at 45-65° C. in a nitrogen atmosphere for 4-7 h, and after the reaction is completed, pouring the product into ice water to promote precipitation, filtering, washing with cold water, and vacuum drying at 40-60° C. for 4-6 h to obtain the modified dispersant;
[0042] (2) adding TiCl4 to deionized water to prepare a 40-50 wt% TiCl4 solution at 25-35° C.;
[0043] (3) adding the modified dispersant into deionized water to prepare a 0.2-1 wt % modified dispersant solution at 75-95° C.;
[0044] (4) adding the TiCl4 solution to the modified dispersant solution, wherein the volume ratio of the TiCl4 solution to the modified dispersant solution is 1:1-2, stirring and heat-insulating at 80-100° C. for 40-80 minutes to obtain a titanic acid solution;
[0045] (5) naturally cooling the metatitanic acid solution to below 40° C., filtering to obtain a metatitanic acid filter cake, and filtering to reduce the moisture content of the metatitanic acid filter cake to below 50%;
[0046] (6) The titanic acid filter cake is placed in a sagger, sintered at 700-900° C. for 2-4 hours, and crushed with a jet mill to a size of 160-200 meshes to obtain the ultrafine TiO2 powder.
[0047] The present invention will be further described below through specific embodiments.
[0048] Example 1
[0049] A method for preparing ultrafine TiO2 powder comprises the following steps:
[0050] (1) 1.5 g of 2,4,6-triaminopyrimidine was dissolved in 60 mL of DMSO, and then 5.0 g of 1,4-butane sultone was added, and the mixture was stirred at 30° C. for 1 h, and nitrogen was introduced to expel the air. The mixture was stirred and reacted at 65° C. for 4 h in a nitrogen atmosphere. After the reaction was completed, the product was poured into ice water to promote precipitation, filtered, washed with cold water, and vacuum dried at 60° C. for 4 h to obtain the modified dispersant;
[0051] (2) adding TiCl4 into deionized water to prepare a 45 wt% TiCl4 solution at 30°C;
[0052] (3) adding the modified dispersant into deionized water to prepare a 0.6 wt % modified dispersant solution at 80° C.;
[0053] (4) adding the TiCl4 solution to the modified dispersant solution, the volume ratio of the TiCl4 solution to the modified dispersant solution being 1:2, stirring and hydrolyzing at 90°C for 60 minutes to obtain a titanic acid solution;
[0054] (5) naturally cooling the metatitanic acid solution to below 40° C., filtering to obtain a metatitanic acid filter cake, and filtering to reduce the moisture content of the metatitanic acid filter cake to below 50%;
[0055] (6) The titanic acid filter cake is placed in a sagger, sintered at 700°C for 4 hours, and crushed with a jet mill to 200 mesh to obtain the ultrafine TiO2 powder. TiO2 content ≥ 99.9wt%, chlorine content ≤ 0.005wt%, D 50 0.16 μm, specific surface area 25.31 m 2 / g, its SEM photo is shown in Figure 1 .
[0056] Example 2
[0057] A method for preparing ultrafine TiO2 powder comprises the following steps:
[0058] (1) 1.2 g of 2,4,6-triaminopyrimidine was dissolved in 60 mL of DMSO, and then 4.2 g of 1,4-butane sultone was added, and the mixture was stirred at 25° C. for 2 h, and nitrogen was introduced to expel the air. The mixture was stirred at 50° C. for 5 h in a nitrogen atmosphere. After the reaction was completed, the product was poured into ice water to promote precipitation, filtered, washed with cold water, and vacuum dried at 50° C. for 5 h to obtain the modified dispersant;
[0059] (2) adding TiCl4 into deionized water to prepare a 45 wt% TiCl4 solution at 30°C;
[0060] (3) adding the modified dispersant into deionized water to prepare a 0.6 wt % modified dispersant solution at 80° C.;
[0061] (4) adding the TiCl4 solution to the modified dispersant solution, the volume ratio of the TiCl4 solution to the modified dispersant solution being 1:2, stirring and hydrolyzing at 90°C for 60 minutes to obtain a titanic acid solution;
[0062] (5) naturally cooling the metatitanic acid solution to below 40° C., filtering to obtain a metatitanic acid filter cake, and filtering to reduce the moisture content of the metatitanic acid filter cake to below 50%;
[0063] (6) The titanic acid filter cake is placed in a sagger, sintered at 800°C for 3 hours, and crushed with a jet mill to 200 mesh to obtain the ultrafine TiO2 powder. TiO2 content ≥ 99.9wt%, chlorine content ≤ 0.005wt%, D 50 0.21 μm, specific surface area 23.45 m 2 / g.
[0064] Example 3
[0065] A method for preparing ultrafine TiO2 powder comprises the following steps:
[0066] (1) dissolving 1 g of 2,4,6-triaminopyrimidine in 60 mL of DMSO, then adding 3.3 g of 1,4-butane sultone, stirring at 20° C. for 3 h, introducing nitrogen to expel air, stirring and reacting at 45° C. for 7 h in a nitrogen atmosphere, and after the reaction is completed, pouring the product into ice water to promote precipitation, filtering, washing with cold water, and vacuum drying at 40° C. for 6 h to obtain the modified dispersant;
[0067] (2) adding TiCl4 into deionized water to prepare a 45 wt% TiCl4 solution at 30°C;
[0068] (3) adding the modified dispersant into deionized water to prepare a 0.6 wt % modified dispersant solution at 80° C.;
[0069] (4) adding the TiCl4 solution to the modified dispersant solution, the volume ratio of the TiCl4 solution to the modified dispersant solution being 1:2, stirring and hydrolyzing at 90°C for 60 minutes to obtain a titanic acid solution;
[0070] (5) naturally cooling the metatitanic acid solution to below 40° C., filtering to obtain a metatitanic acid filter cake, and filtering to reduce the moisture content of the metatitanic acid filter cake to below 50%;
[0071] (6) The titanic acid filter cake is placed in a sagger, sintered at 700°C for 4 hours, and crushed with a jet mill to 200 mesh to obtain the ultrafine TiO2 powder. TiO2 content ≥ 99.9wt%, chlorine content ≤ 0.005wt%, D 50 0.26μm, specific surface area 21.74m2 / g.
[0072] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.
Claims
1. A method for preparing ultrafine TiO2 powder, characterized in that: The steps include: (1) Adding TiCl4 into deionized water to prepare a TiCl4 solution; (2) adding the modified dispersant into deionized water to prepare a modified dispersant solution; (3) adding the TiCl4 solution to the modified dispersant solution, preserving the solution for hydrolysis, and obtaining a titanic acid solution; (4) naturally cooling the titanic acid solution for aging, and filtering to obtain a titanic acid filter cake; (5) The titanic acid filter cake is placed in a sagger, sintered at high temperature, and crushed to obtain the ultrafine TiO2 powder.
2. The preparation method according to claim 1, characterized in that: In step (1), the solution is prepared at 25-35° C., and the concentration of the TiCl 4 solution is 40-50 wt %.
3. The preparation method according to claim 1, characterized in that: In step (2), the solution is prepared at 75-95° C., and the concentration of the modified dispersant solution is 0.2-1 wt %.
4. The preparation method according to claim 1, characterized in that: In step (3), the volume ratio of the TiCl4 solution to the modified dispersant solution is 1:1-2; and the heat preservation and hydrolysis conditions are stirring and heat preservation and hydrolysis at 80-100°C for 40-80 minutes.
5. The preparation method according to claim 1, characterized in that: In step (4), the temperature is naturally lowered to below 40° C., and the filter is pressed to reduce the moisture content of the titanic acid filter cake to below 50%.
6. The preparation method according to claim 1, characterized in that: In step (5), the sintering conditions are sintering at 700-900° C. for 2-4 hours; and crushing with a jet mill to 160-200 mesh.
7. The preparation method according to claim 1, characterized in that: In step (2), the preparation method of the modified dispersant comprises the following steps: dissolving 2,4,6-triaminopyrimidine in DMSO, then adding 1,4-butane sultone, stirring and mixing evenly, introducing nitrogen to expel air, heating to react under a nitrogen atmosphere, pouring the product into ice water after the reaction to promote precipitation, filtering, washing with cold water, and vacuum drying to obtain the modified dispersant.
8. The preparation method according to claim 7, characterized in that: The usage ratio of 2,4,6-triaminopyrimidine, DMSO and 1,4-butane sultone is 1-1.5 g: 40-60 mL: 3.3-5.0 g.
9. The preparation method according to claim 7, characterized in that: The stirring and mixing conditions are stirring at 20-30°C for 1-3 hours; the temperature reaction conditions are stirring and reacting at 45-65°C for 4-7 hours; and the drying conditions are vacuum drying at 40-60°C for 4-6 hours.
10. An ultrafine TiO2 powder prepared by the preparation method according to any one of claims 1 to 9.