Preparation method and application of micron-sized spherical silicon dioxide
By regulating the preparation process parameters of silicic acid solution and silica sol, spray drying technology is used to simplify the preparation process of spherical silica, solving the problems of cumbersome processing and high resource consumption in the wet process, and achieving efficient and energy-saving micro-scale spherical shapes Preparation of silica.
Patent Information
- Application Number
- CN202410361702.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-28
- Publication Date
- 2024-12-20
- Estimated Expiration
- 2044-03-28
AI Technical Summary
The processing process of spherical silica in the wet production process is cumbersome and consumes a lot of energy and water resources, making it difficult to meet the purity requirements of medicinal standards.
By regulating the preparation process parameters of silicic acid solution and silica sol, cation exchange resin is used to remove alkali metal ions, conduct solization reaction, and micron-scale spherical silica is prepared by using an air-flow spray dryer to simplify the processing process and control alkali metal ions. Content and process parameters to save energy and water resources.
The preparation process of spherical silica is significantly simplified, the consumption of energy and water resources is reduced, and silica microspheres with different median particle sizes are prepared, which improves the purity and stability of the product.
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Figure CN117963933B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of silicon dioxide preparation, and in particular to a preparation method and application of micron-sized spherical silicon dioxide. Background Art
[0002] Spherical silica has the characteristics of good fluidity, low stress concentration, large specific surface area, and low friction coefficient, and is widely used as a food additive, cosmetics, and pharmaceutical excipients. As a pharmaceutical excipient, spherical silica can not only shape drugs, act as a carrier, and improve drug stability, but also play an important role in solubilization, dissolution, and sustained release, which is of great significance to improving the quality, safety, and effectiveness of drugs.
[0003] The production process of spherical silica mainly includes dry production process and wet production process. In the dry production process, silica slurry and alkali solution are reacted to generate hydroxide colloidal body, and then the hydroxide colloidal body is molded, dried at high temperature and calcined in sequence to obtain spherical silica. Although this method can obtain high-quality spherical silica, a large amount of dust and gas will be generated during the treatment process, which will cause great pollution to the environment. In addition, the raw materials may lose nutrients and characteristics after heat treatment. In the wet production process, orthosilicic acid is usually prepared from silicate as raw material, and then the orthosilicic acid is dehydrated and condensed under acid-base catalysis to form high-molecular polysilicic acid. The polysilicic acid is dried and calcined in sequence to obtain spherical silica. The wet production process has the advantages of less pollution during the treatment process and high product quality. However, in order to make the purity of the product meet the pharmaceutical standard, the product needs to be washed, filtered and dried twice during the production process of spherical silica. The treatment process is cumbersome and consumes a lot of energy and water resources. Summary of the invention
[0004] In view of the technical problems of complicated processing and high consumption of energy and water resources in preparing spherical silicon dioxide by wet production process, the present invention provides a preparation method and application of micron-sized spherical silicon dioxide. By adjusting the preparation process parameters of silicic acid solution and silica sol and spray-drying the silica sol, the processing process of micron-sized spherical silicon dioxide is simplified, and energy and water resources are saved.
[0005] The present invention provides a method for preparing micron-sized spherical silicon dioxide, comprising the following steps:
[0006] Step 1: an alkali metal silicate solution with a concentration of 10wt%-18wt% is subjected to ion exchange through a cation exchange resin to remove alkali metal ions and obtain a silicic acid solution;
[0007] Step 2: The silicic acid solution is subjected to a sol reaction under the action of an acidic catalyst or an alkaline catalyst to form a silica sol with a solid content of 8wt%-18wt%, a pH value of the silica sol of 4-9, a sol reaction temperature of 70-80°C, and a sol reaction time of 1-3h;
[0008] Step 3: spray-dry the silica sol to form micron-sized spherical silicon dioxide, wherein the nozzle pressure of the spray drying is 0.15Mpa, the air inlet temperature of the spray drying is 320-350°C, and the air outlet temperature of the spray drying is 95-110°C.
[0009] In step 1, the alkali metal ion content of the silicic acid solution can be adjusted according to product requirements. In the present invention, the alkali metal ion content of the silicic acid solution is controlled to be less than 500 ppm.
[0010] Furthermore, in step 1, the alkali silicate solution is a sodium silicate solution or a potassium silicate solution.
[0011] Furthermore, in step 2, the acidic catalyst is one or more of sulfuric acid, hydrochloric acid, acetic acid, and citric acid.
[0012] Furthermore, in step 2, the alkaline catalyst is aqueous ammonia.
[0013] Furthermore, in step 2, the silica sol is concentrated by heating under reduced pressure to obtain a series of stable silica sols of different concentrations.
[0014] Furthermore, in step 3, the spray drying uses an airflow spray dryer, and the nozzle diameter of the airflow spray dryer is 2 mm. The silica sol is dehydrated and gelled in the spray dryer, and dried to form micron-sized spherical silica.
[0015] Furthermore, the median particle size of the micron-sized spherical silica is 1-50 μm.
[0016] Furthermore, the concentration of the acidic catalyst and the alkaline catalyst is 5 wt %.
[0017] The beneficial effects of the present invention are:
[0018] The present invention provides a preparation method and application of micron-sized spherical silica, firstly using a cation exchange resin to remove alkali metal ions in an alkali metal silicate solution to obtain a silicic acid solution; then the silicic acid solution is subjected to a sol reaction under relatively mild conditions to obtain a silica sol that is not easy to solidify and has good stability; and then the micron-sized spherical silica is prepared by spray drying. The preparation method provided by the present invention prepares silica microspheres with different median particle sizes by regulating the process parameters in the preparation process of micron-sized spherical silica, and at the same time controls the alkali metal ion content at a relatively low level, thereby saving the steps of washing, filtering, and drying after filtering, and significantly saving energy and water resources. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0020] Figure 1 This is a scanning electron microscope image of the micron-sized spherical silicon dioxide prepared in Example 1.
[0021] Figure 2 This is a particle size distribution diagram of the micron-sized spherical silicon dioxide prepared in Example 1.
[0022] Figure 3 This is a scanning electron microscope image of the micron-sized spherical silicon dioxide prepared in Example 2.
[0023] Figure 4 This is the particle size distribution diagram of the micron-sized spherical silica prepared in Example 2.
[0024] Figure 5 This is a scanning electron microscope image of the micron-sized spherical silicon dioxide prepared in Example 3.
[0025] Figure 6 This is the particle size distribution diagram of the micron-sized spherical silica prepared in Example 3.
[0026] Figure 7 This is a scanning electron microscope image of the micron-sized spherical silicon dioxide prepared in Example 4.
[0027] Figure 8 This is the particle size distribution diagram of the micron-sized spherical silica prepared in Example 4.
[0028] Fig. 9 This is a scanning electron microscope image of the silicon dioxide prepared in Comparative Example 1.
[0029] Fig.10 This is the particle size distribution diagram of the silicon dioxide prepared in Comparative Example 1.
[0030] Fig.11 This is a scanning electron microscope image of the silicon dioxide prepared in Comparative Example 2. DETAILED DESCRIPTION
[0031] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.
[0032] Example 1
[0033] Step 1: 100 g of a 15 wt % sodium silicate aqueous solution is subjected to ion exchange by passing it through a 732 type cation exchange resin to remove sodium ions, thereby obtaining a neutral silicic acid solution having a solid content of 8.6 wt %, wherein the sodium ion content in the silicic acid solution is 335 ppm.
[0034] Step 2: Add 5 wt% ammonia solution to the neutral silicic acid solution, adjust the pH of the silicic acid solution to 9, and react at 70°C for 2 hours to form alkaline silica sol, cool to room temperature, and set aside.
[0035] Step 3: Use an airflow spray dryer to spray dry the alkaline silica sol to form micron-sized spherical silica, wherein the nozzle diameter is 2 mm, the nozzle pressure of the spray dryer is 0.15 MPa, the inlet air temperature of the spray dryer is 350°C, and the outlet air temperature of the spray dryer is 110°C. The scanning electron microscope image of the obtained micron-sized spherical silica is as follows: Figure 1 As shown in Figure 1, the sample has a spherical morphology. The particle size distribution diagram of the obtained micron-sized spherical silica is shown in Figure 1. Figure 2 As shown, the median particle size of the spherical silica is 4.27 μm, and the dispersibility is good.
[0036] Example 2
[0037] Step 1: 100 g of a 15 wt % sodium silicate aqueous solution is subjected to ion exchange by passing it through a 732 type cation exchange resin to remove sodium ions, thereby obtaining a neutral silicic acid solution having a solid content of 8.6 wt %, wherein the sodium ion content in the silicic acid solution is 316 ppm.
[0038] Step 2: Add 5 wt% ammonia solution to the neutral silicic acid solution, adjust the pH of the silicic acid solution to 9, and keep it warm at 70°C for 3 hours to form alkaline silica sol, and concentrate the alkaline silica sol under reduced pressure at 70°C to a solid content of 10 wt%, cool to room temperature, and set aside.
[0039] Step 3: Use an airflow spray dryer to spray dry the alkaline silica sol to form micron-sized spherical silica, wherein the nozzle diameter is 2 mm, the nozzle pressure of the spray dryer is 0.15 MPa, the inlet air temperature of the spray dryer is 320°C, and the outlet air temperature of the spray dryer is 95°C. The scanning electron microscope image of the obtained micron-sized spherical silica is as follows: Figure 3 As shown in Figure 1, the sample has a spherical morphology. The particle size distribution diagram of the obtained micron-sized spherical silica is shown in Figure 1. Figure 4 As shown, the median particle size of the spherical silica is 5.63 μm, and the dispersibility is good.
[0040] Example 3
[0041] Step 1: 100 g of a 15 wt % sodium silicate aqueous solution is subjected to ion exchange by passing it through a 732 type cation exchange resin to remove sodium ions, thereby obtaining a neutral silicic acid solution having a solid content of 8.6 wt %, wherein the sodium ion content in the silicic acid solution is 348 ppm.
[0042] Step 2: Add 5 wt% ammonia solution to the neutral silicic acid solution, adjust the pH of the silicic acid solution to 9, and keep it warm at 80°C for 2 hours to form alkaline silica sol, and concentrate the alkaline silica sol under reduced pressure at 80°C to a solid content of 18 wt%, cool it to room temperature, and set it aside.
[0043] Step 3: Use an airflow spray dryer to spray dry the alkaline silica sol to form micron-sized spherical silica, wherein the nozzle diameter is 2 mm, the nozzle pressure of the spray dryer is 0.15 MPa, the inlet air temperature of the spray dryer is 320°C, and the outlet air temperature of the spray dryer is 95°C. The scanning electron microscope image of the obtained micron-sized spherical silica is as follows: Figure 5 As shown in Figure 1, the sample has a spherical morphology. The particle size distribution diagram of the obtained micron-sized spherical silica is shown in Figure 1. Figure 6 As shown, the median particle size of the spherical silica is 7.24 μm, and the dispersibility is good.
[0044] Example 4
[0045] Step 1: 100 g of a 15 wt % sodium silicate aqueous solution is subjected to ion exchange by passing it through a 732 type cation exchange resin to remove sodium ions, thereby obtaining a neutral silicic acid solution having a solid content of 8.6 wt %, wherein the sodium ion content in the silicic acid solution is 372 ppm.
[0046] Step 2: Add 5wt% hydrochloric acid solution to the neutral silicic acid solution, adjust the pH of the silicic acid solution to 4, and keep it warm at 70°C for 2 hours to form an acidic silica sol, and concentrate the acidic silica sol under reduced pressure at 70°C to a solid content of 15wt%, cool it to room temperature, and set it aside.
[0047] Step 3: Use an airflow spray dryer to spray dry the acidic silica sol to form micron-sized spherical silica, wherein the nozzle diameter is 2 mm, the nozzle pressure of the spray drying is 0.15 MPa, the inlet air temperature of the spray drying is 350°C, and the outlet air temperature of the spray drying is 110°C. The scanning electron microscope image of the obtained micron-sized spherical silica is as follows: Figure 7 As shown in Figure 1, the sample has a spherical morphology. The particle size distribution diagram of the obtained micron-sized spherical silica is shown in Figure 1. Figure 8 As shown, the median particle size of the spherical silica is 6.19 μm, and the dispersibility is good.
[0048] Comparative Example 1
[0049] Step 1: 100 g of a 15 wt % sodium silicate aqueous solution is subjected to ion exchange by passing it through a 732 type cation exchange resin to remove sodium ions, thereby obtaining a neutral silicic acid solution having a solid content of 8.6 wt %, wherein the sodium ion content in the silicic acid solution is 320 ppm.
[0050] Step 2: Add 5 wt% ammonia solution to the neutral silicic acid solution, adjust the pH of the silicic acid solution to 9, and keep it reacted at 70°C for 2 hours to form alkaline silica sol, dilute the alkaline silica sol to a solid content of 5 wt%, cool to room temperature, and set aside.
[0051] Step 3: Use an airflow spray dryer to spray dry the alkaline silica sol to form micron-sized silica, wherein the nozzle diameter is 2 mm, the nozzle pressure of the spray dryer is 0.15 MPa, the inlet air temperature of the spray dryer is 350°C, and the outlet air temperature of the spray dryer is 110°C. The scanning electron microscope image of the obtained micron-sized silica is as follows: Fig. 9 As shown in the figure, most of the samples are irregular spherical structures with holes on the surface. This is because the low-solid alkaline silica sol has a high water content. During the spray drying process, the droplets quickly form a gel shell in the drying chamber. At this time, the water inside the droplets does not have time to completely evaporate. When the air pressure inside the shell exceeds the local pressure of the shell, vents appear in local parts, forming a damaged spherical shell structure. The particle size distribution of the obtained micron-sized silica is shown in the figure. Fig.10 As shown, the median particle size of the spherical silica is 4.18 μm.
[0052] Comparative Example 2
[0053] Step 1: 100 g of a 15 wt % sodium silicate aqueous solution is subjected to ion exchange by passing it through a 732 type cation exchange resin to remove sodium ions, thereby obtaining a neutral silicic acid solution having a solid content of 8.6 wt %, wherein the sodium ion content in the silicic acid solution is 336 ppm.
[0054] Step 2: Concentrate the neutral silicic acid solution under reduced pressure at 80° C. to a solid content of 15 wt %, cool to room temperature, and set aside. The concentrated neutral silicic acid solution turns into silica gel after cooling to room temperature.
[0055] Step 3: Use an airflow spray dryer to spray-dry the silica gel to form silicon dioxide, wherein the nozzle diameter is 2 mm, the nozzle pressure of the spray drying is 0.15 MPa, the inlet air temperature of the spray drying is 350°C, and the outlet air temperature of the spray drying is 110°C. The scanning electron microscope image of the obtained silicon dioxide is as follows: Fig.11 As shown, the silica sample exhibits a non-spherical and irregular morphology.
[0056] Although the present invention has been described in detail with reference to the accompanying drawings and in combination with the preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, a person of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions shall be within the scope of the present invention. Any person of ordinary skill in the art may easily think of changes or substitutions within the technical scope disclosed by the present invention, and these shall be within the scope of protection of the present invention.
Claims
1. A method for preparing micron-sized spherical silicon dioxide, characterized in that: The steps include: Step 1: an alkali metal silicate solution with a concentration of 10wt%-18wt% is subjected to ion exchange through a cation exchange resin to remove alkali metal ions and obtain a silicic acid solution; Step 2: The silicic acid solution is subjected to a sol reaction under the action of an acidic catalyst or an alkaline catalyst to form a silica sol with a solid content of 8wt%-18wt%, a pH value of the silica sol of 4-9, a sol reaction temperature of 70-80°C, and a sol reaction time of 1-3h; Step 3: spray-drying the silica sol to form micron-sized spherical silica, wherein the nozzle pressure of the spray drying is 0.15Mpa, the inlet air temperature of the spray drying is 320-350°C, and the outlet air temperature of the spray drying is 95-110°C; In step 2, the silica sol is concentrated by heating under reduced pressure; The median particle size of micron-sized spherical silica is 1-50 μm; In step 2, the acidic catalyst is one or more of sulfuric acid, hydrochloric acid, acetic acid, and citric acid; In step 2, the alkaline catalyst is aqueous ammonia; The concentration of the acidic catalyst and the basic catalyst was 5 wt %.
2. The method for preparing micron-sized spherical silicon dioxide according to claim 1, characterized in that: In step 1, the alkali metal silicate solution is a sodium silicate solution or a potassium silicate solution.
3. The method for preparing micron-sized spherical silicon dioxide according to claim 1, characterized in that: In step 3, an airflow spray dryer is used for spray drying, and the nozzle diameter of the airflow spray dryer is 2 mm.