A simple method for preparing cerium-aluminum coated titanium dioxide
Through the oscillating oscillated aluminum littering film titanium pink, the complex problems of the regulation of the envelope parameters and the addition of dispersing agents in the existing processes are solved, and the high whiteness and weather resistance of titanium pink powder are improved.
Patent Information
- Application Number
- CN202411564616.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-05
- Publication Date
- 2025-01-28
- Estimated Expiration
- 2044-11-05
AI Technical Summary
The existing titanium dioxide coating process requires precise control of the coating parameters and requires the addition of dispersants, resulting in complex process, high cost and troublesome operation.
Adopt a pyrine -soluble method, to form polyethylene pyrigne ketones into a nitrate solution, and mix with the unpacking of titanium pink powder slurry under the heating conditions of the water bath. And aluminum oxide envelope, obtains titanium pink powder of aluminum bay.
With the need to accurately regulate and add a dispersant, the envelope parameters do not need to prepare a uniform oxidation nanometer distribution and high -white aluminum liter titanium pink, which improves the weather tolerance and decentralization of titanium pink powder. sex.
Smart Images
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Abstract
Description
Technical Field
[0001] The invention relates to a simple method for preparing cerium-aluminum coated titanium dioxide, belonging to the technical field of titanium dioxide post-processing. Background Art
[0002] The main component of titanium dioxide is titanium dioxide (TiO2), which is currently the most widely used white pigment and is used in coatings, plastics, papermaking, inks, chemical fibers, medicine and other industries. At present, the main production methods are sulfuric acid method and chlorination method. Post-treatment of TiO2 particles with inorganic and organic coating to improve their weather resistance and dispersibility is an indispensable link in the production process of titanium dioxide. The weather resistance of titanium dioxide refers to the ability to resist loss of gloss, yellowing, and powdering under natural light conditions. The use of inorganic oxides mainly containing zirconium, silicon and aluminum for coating is a common practice to improve the weather resistance of titanium dioxide. This oxide coating is usually chemically inert and electrically insulating, which can prevent the photogenerated electrons and holes generated by the TiO2 particles when excited by light from diffusing to the surface of the particles, thereby reducing its photocatalytic degradation activity.
[0003] Cerium oxide (CeO x ) has good UV shielding ability and evenly deposits CeO on the surface of TiO2 particles x It can significantly improve the weather resistance of TiO2 pigments. x The coating method is chemical precipitation, that is, using water-soluble cerium salts (cerium nitrate, cerium sulfate, cerium acetate, cerium chloride) to form cerium hydroxide precipitation or cerium oxide precipitation on the surface of TiO2 particles through chemical reaction. However, coating is usually carried out in a larger tank reactor (usually with a volume greater than 100L) using a mechanical stirrer (usually with a speed lower than 60rpm), which makes it difficult to achieve perfect stirring and mass transfer, and there are local CeO x The high degree of supersaturation and self-nucleation will not only lead to uneven or too thick coating layer on the surface of TiO2 particles, which will reduce the light scattering ability and whiteness of titanium dioxide products, but also lead to low crystallinity of coating layer, which will affect CeO x The stability of color causes the titanium dioxide product to change color. Therefore, in order to obtain a coating with an ideal morphology, different precipitation methods need to be used according to industrial requirements to accurately control the addition rate of the precipitant and cerium salt, the pH value of the slurry, the temperature, the stirring speed and other factors. In industry, this production method that requires strict control of conditions will bring many difficulties and increase the cost of the titanium dioxide coating process.
[0004] In order to further improve the whiteness and weather resistance of titanium dioxide, a layer of aluminum oxide or aluminum phosphate is usually coated on its surface. The traditional method of cerium-aluminum coating of titanium dioxide usually uses the sol-gel method, that is, first coating cerium oxide on the surface of titanium dioxide by chemical precipitation, and then coating aluminum oxide or aluminum phosphate on the surface of titanium dioxide. In actual production, the coating parameters need to be precisely controlled when coating cerium oxide, and dispersants need to be added when coating aluminum oxide or aluminum phosphate, otherwise it is easy to cause uneven coating problems. The whole process is relatively cumbersome and troublesome to operate. Summary of the invention
[0005] In order to solve the deficiencies of the prior art, the purpose of the present invention is to provide a simple method for preparing cerium-aluminum coated titanium dioxide which does not require precise control of coating parameters and does not require the addition of dispersants.
[0006] In order to achieve the above object, the present invention adopts the following technical solution:
[0007] A simple method for preparing cerium-aluminum coated titanium dioxide comprises the following steps:
[0008] (1) Add polyvinyl pyrrolidone to the cerium nitrate solution and continue stirring for 30 minutes, then add ammonia water dropwise and continue stirring for 60 minutes to slowly form a light yellow cerium sol;
[0009] (2) placing the uncoated titanium dioxide slurry in a reaction container, heating it to 60°C in a water bath, then adjusting the pH value to 8.5, then slowly dropping the cerium sol, while maintaining the pH value of the reaction system at 8.5, and aging at 60°C for 30 minutes after the dropping is completed to obtain a cerium oxide nanoparticle coated titanium dioxide slurry;
[0010] (3) The cerium oxide nanoparticle coated titanium dioxide slurry was heated to 80°C, and then the pH value was adjusted to 9. Then, aluminum sulfate solution and phosphoric acid solution were added dropwise while stirring. The pH value of the reaction system was maintained at 9 during the addition. After the addition was completed, the mixture was aged at 80°C for 1 hour, naturally cooled to room temperature, and then post-treated to obtain cerium aluminum coated titanium dioxide with a mass ratio of 3%.
[0011] Preferably, in step (1), the concentrations of cerium nitrate and ammonia water are 0.05 M and 2 M respectively, and the dosage ratio of polyvinyl pyrrolidone, cerium nitrate solution and ammonia water is 2 g: 200 mL: 5 mL.
[0012] Preferably, in step (2), the concentration of the uncoated titanium dioxide slurry is 300 g / L, the dosage ratio of the uncoated titanium dioxide slurry to the cerium sol is 100 mL:3.6 mL to 11.2 mL; and the dropping speed of the cerium sol is 0.5 mL / min.
[0013] Preferably, in step (3), the concentrations of the aluminum sulfate solution and the phosphoric acid solution are 0.3M and 0.15M respectively, and the dosage ratio of the cerium oxide nanoparticle coated titanium dioxide slurry, the aluminum sulfate solution and the phosphoric acid solution is 110mL:3.3mL:3.3mL; and the post-treatment sequentially includes: filtration, washing the precipitate with deionized water, drying and grinding the precipitate.
[0014] The benefit of the present invention lies in that when cerium sol containing a large amount of cerium oxide nanoparticles is used as a raw material to perform cerium-aluminum coating on titanium dioxide, it is not necessary to precisely control the coating parameters and to add a dispersant, so that cerium-aluminum coated titanium dioxide can be prepared. The process is simple and controllable, the operation is convenient, and the cerium oxide nanoparticles are more evenly distributed on the surface of the titanium dioxide particles, and the whiteness and weather resistance of the titanium dioxide are better. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 It is the SEM image of uncoated titanium dioxide;
[0016] Figure 2 This is the SEM image of cerium oxide nanoparticles coated titanium dioxide;
[0017] Figure 3 This is the TEM image of cerium oxide nanoparticles coated titanium dioxide;
[0018] Figure 4 is the SEM image of cerium-aluminum coated titanium dioxide 1;
[0019] Figure 5 This is the SEM image of cerium-aluminum coated titanium dioxide 4. DETAILED DESCRIPTION
[0020] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.
[0021] 1. Preparation of cerium-aluminum coated titanium dioxide
[0022] Example 1: Preparation of cerium-aluminum coated titanium dioxide by cerium sol method
[0023] 2.0 g of polyvinyl pyrrolidone was added to 200.0 mL of 0.05 M cerium nitrate solution, and the mixture was stirred for 30 min. Then 5.0 mL of 2 M ammonia water was added dropwise, and the mixture was stirred for 60 min to gradually form a light yellow cerium sol.
[0024] The uncoated titanium dioxide was prepared into an uncoated titanium dioxide slurry with water at a concentration of 300 g / L. 100 mL of the uncoated titanium dioxide slurry was placed in a reaction container, heated to 60°C in a water bath, and then the pH value was adjusted to 8.5 with a 1M sodium hydroxide solution, and then 7.2 mL of the previously prepared cerium sol was slowly added at a flow rate of 0.5 mL / min. While adding the cerium sol, a 1M sodium hydroxide solution was used to maintain the pH value of the reaction system at 8.5. After the addition was completed, the reaction was aged at 60°C for 30 minutes to obtain 110 mL of cerium oxide nanoparticle coated titanium dioxide slurry.
[0025] The cerium oxide nanoparticle coated titanium dioxide slurry (110 mL) prepared above was heated to 80°C, and then the pH value was adjusted to 9 with a 1M sodium hydroxide solution. Subsequently, 3.3 mL of a 0.3M aluminum sulfate solution and 3.3 mL of a 0.15M phosphoric acid solution were added dropwise while stirring. During the addition, a 1M sodium hydroxide solution was used to maintain the pH value of the reaction system at 9. After the addition was completed, the mixture was aged at 80°C for 1 h, cooled naturally to room temperature, and then filtered, the precipitate was washed with deionized water, dried (120°C) and ground to obtain a cerium aluminum coated titanium dioxide 1 with a mass ratio (m=AlPO4:TiO2) of 3%.
[0026] Example 2: Preparation of cerium-aluminum coated titanium dioxide by cerium sol method
[0027] The method is basically the same as Example 1, except that the amount of cerium sol is reduced by 0.5 times, that is, 3.6 mL of cerium sol is added dropwise to obtain cerium-aluminum coated titanium dioxide 2 with a mass ratio (m=AlPO4:TiO2) of 3%.
[0028] Example 3: Preparation of cerium-aluminum coated titanium dioxide by cerium sol method
[0029] The method is basically the same as Example 1, except that the amount of cerium sol is increased by 0.5 times, that is, 11.2 mL of cerium sol is added dropwise to obtain cerium-aluminum coated titanium dioxide 3 with a mass ratio (m=AlPO4:TiO2) of 3%.
[0030] Comparative Example: Preparation of Cerium-Aluminum Coated Titanium Dioxide by Sol-Gel Method
[0031] Take 128.0g of uncoated titanium dioxide slurry with a concentration of 300g / L in a reaction container, heat it to 80°C in a water bath, take 12mL of 0.05M cerium sulfate solution and add it to the uncoated titanium dioxide slurry, use 1M sodium hydroxide solution to maintain the pH value of the reaction system at 9, and continue stirring at 80°C for 2h to obtain cerium-coated titanium dioxide slurry.
[0032] The temperature of the cerium-coated titanium dioxide slurry prepared above was maintained at 80°C, and dispersant sodium hexametaphosphate was added to the cerium-coated titanium dioxide slurry at a mass ratio of 0.1%. The pH value of the reaction system was adjusted to 9 with a 1M sodium hydroxide solution, and then 3.3mL of a 0.3M aluminum sulfate solution and 3.3mL of a 0.15M phosphoric acid solution were simultaneously added dropwise to the reaction system while stirring. During the addition, the pH value of the reaction system was maintained at 9 with a 1M sodium hydroxide solution. After the addition was completed, the mixture was aged at 80°C for 1h, and naturally cooled to room temperature, and then filtered, the precipitate was washed with deionized water, dried at 120°C and the precipitate was ground to obtain a cerium-aluminum-coated titanium dioxide 4 with a mass ratio (m=AlPO4:TiO2) of 3%.
[0033] 2. Observe the morphology of cerium aluminum coated titanium dioxide
[0034] The cerium oxide nanoparticle coated titanium dioxide slurry was prepared by the same method as in Example 1, and then dried at 120° C. and ground to obtain the cerium oxide nanoparticle coated titanium dioxide.
[0035] The uncoated titanium dioxide, the cerium oxide nanoparticle coated titanium dioxide, the cerium aluminum coated titanium dioxide 1 and the cerium aluminum coated titanium dioxide 4 were observed by scanning electron microscope (SEM) and / or transmission electron microscope (TEM).
[0036] SEM image of uncoated titanium dioxide is shown in Figure 1 .Depend on Figure 1 It can be seen that the surface of uncoated titanium dioxide is smooth and has good dispersibility.
[0037] SEM image of cerium oxide nanoparticles coated titanium dioxide Figure 2 .Depend on Figure 2 It can be seen that after titanium dioxide is coated with cerium oxide nanoparticles, the surface is still smooth and the dispersibility is still good.
[0038] TEM image of cerium oxide nanoparticles coated titanium dioxide Figure 3 .Depend on Figure 3 It can be seen that the particle size of the cerium oxide nanoparticles coated on the surface of titanium dioxide is between 5nm and 10nm.
[0039] The SEM image of cerium aluminum coated titanium dioxide 1 is shown in Figure 4 .Depend on Figure 4 It can be seen that the aluminum phosphate coated on the surface of titanium dioxide has an obvious flaky structure, which makes the surface of titanium dioxide rough, with small flake protrusions and good shell continuity.
[0040] The SEM image of cerium aluminum coated titanium dioxide 4 is shown in Figure 5 .Depend on Figure 5 It can be seen that the aluminum phosphate coated on the surface of titanium dioxide is in granular form and has poor dispersibility.
[0041] 3. Testing the pigment properties and weather resistance of cerium aluminum coated titanium dioxide
[0042] The pigment performance test results of each cerium-aluminum coated titanium dioxide are shown in Table 1, and the weather resistance test results are shown in Table 2.
[0043] Table 1 Pigment performance test results
[0044]
[0045] Table 2 Weathering resistance test results
[0046]
[0047] From Table 1 and Table 2, we can see that:
[0048] (1) When cerium-aluminum coated titanium dioxide is prepared by the sol-gel method, although the weather resistance and dispersibility of cerium-aluminum coated titanium dioxide are improved, the pigment properties such as whiteness are not ideal;
[0049] (2) When cerium-aluminum coated titanium dioxide is prepared by the cerium sol method, the pigment properties such as whiteness are improved while ensuring the weather resistance of the cerium-aluminum coated titanium dioxide;
[0050] (3) When preparing cerium-aluminum coated titanium dioxide by the cerium sol method, the greater the amount of cerium sol added, the better the weather resistance of the cerium-aluminum coated titanium dioxide will be, but the whiteness will be slightly reduced.
[0051] It should be noted that the above embodiments are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the embodiments here. Any obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.
Claims
1. A simple method for preparing cerium-aluminum coated titanium dioxide, characterized in that: The following steps are involved: (1) Add polyvinyl pyrrolidone to 0.05M cerium nitrate solution, continue stirring for 30 minutes, then add 2M ammonia water dropwise, the dosage ratio of polyvinyl pyrrolidone, cerium nitrate solution and ammonia water is 2g:200mL:5mL, continue stirring for 60 minutes, and slowly form a light yellow cerium sol; (2) 300 g / L of uncoated titanium dioxide slurry was placed in a reaction container, heated to 60°C in a water bath, and then the pH value was adjusted to 8.5, and then cerium sol was slowly added dropwise, the dosage ratio of uncoated titanium dioxide slurry to cerium sol was 100 mL: 3.6 mL to 11.2 mL, and the pH value of the reaction system was maintained at 8.5 while the cerium sol was added dropwise. After the addition was completed, the reaction was aged at 60°C for 30 min to obtain cerium oxide nanoparticle coated titanium dioxide slurry; (3) The temperature of the cerium oxide nanoparticle coated titanium dioxide slurry was raised to 80°C, and then the pH value was adjusted to 9. Subsequently, 0.3 M aluminum sulfate solution and 0.15 M phosphoric acid solution were added dropwise at the same time. The dosage ratio of the cerium oxide nanoparticle coated titanium dioxide slurry, aluminum sulfate solution and phosphoric acid solution was 110 mL: 3.3 mL: 3.3 mL. The cerium oxide nanoparticle coated titanium dioxide slurry, aluminum sulfate solution and phosphoric acid solution were added dropwise while stirring. During the addition, the pH value of the reaction system was maintained at 9. After the addition was completed, the cerium oxide nanoparticle coated titanium dioxide was aged at 80°C for 1 h, and then naturally cooled to room temperature for post-treatment to obtain cerium aluminum coated titanium dioxide with a mass ratio of 3%.
2. The simple method for preparing cerium aluminum coated titanium dioxide according to claim 1, characterized in that: In step (2), the dropping speed of the cerium sol is 0.5 mL / min.
3. The simple method for preparing cerium aluminum coated titanium dioxide according to claim 1, characterized in that: In step (3), the post-treatment includes: filtration, washing the precipitate with deionized water, drying and grinding the precipitate.