Continuous centrifugal washing method in silicon microsphere production
Patent Information
- Application Number
- CN202411680597.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-22
- Publication Date
- 2025-01-28
AI Technical Summary
The traditional silicon microsphere washing method is cumbersome, time-consuming and low washing efficiency, making it difficult to meet the needs of large-scale industrial production.
Adopting continuous centrifugal washing methods to separate silicon microspheres from was separated from centrifugal solution to achieve fast and efficient washing. Specific steps include preparation, stirring and heating, dripping reaction, stirring and drying of the hybrid solution, and finally get dry and pure silicon micro -ball through multiple centrifugal washing and nitrogen blowing.
The production cycle has been shortened, the production efficiency is improved, and the effects of impurities are effectively removed by multiple washing and centrifugal separation.
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of silicon microsphere production, and relates to a continuous centrifugal washing method in silicon microsphere production. Background Art
[0002] In the preparation process of silicon microspheres, washing is a crucial step. Washing can not only remove impurities and unreacted substances on the surface of silicon microspheres, but also affect the smoothness, dispersion and stability of their surface. Traditional silicon microsphere washing methods mostly use intermittent operation, that is, the prepared silicon microspheres are dispersed in a solvent and washed by stirring, standing, filtering and other steps. However, this method has problems such as cumbersome operation, long time consumption and low washing efficiency, which is difficult to meet the needs of large-scale industrial production.
[0003] In recent years, with the advancement of science and technology and the development of industrial production, the continuous centrifugal washing method has been gradually applied to the washing process of silicon microspheres. The continuous centrifugal washing method uses the centrifugal force to separate the silicon microspheres from the washing liquid, thereby achieving fast and efficient washing. This method has the advantages of simple operation, high washing efficiency, and easy automation control, which can significantly improve the washing effect and production efficiency of silicon microspheres. Summary of the invention
[0004] The purpose of the present invention is to provide a continuous centrifugal washing method in the production of silicon microspheres, which has the characteristics of high production efficiency.
[0005] The purpose of the present invention can be achieved through the following technical solutions:
[0006] A continuous centrifugal washing method for producing silicon microspheres, the specific process of the method is as follows:
[0007] S1: Distilled water and isopropanol were mixed in a volume ratio of 1:(0.5-2), stirred at a speed of 150 r / min for 0.5 h, heated to 30-35° C. while stirring, and continued to stir for 0.5 h after constant temperature to obtain a mixed solution A;
[0008] S2: slowly drop ammonia water with a concentration of 1 mol / L into the mixed solution A at a constant temperature, and continue to stir the solution at a speed of 200 r / min while dropping, the volume ratio of the mixed solution A to the ammonia water is 1:(0.5-1), and after the dropwise addition is completed, a mixed solution B is obtained;
[0009] S3: mixing tetraethyl orthosilicate and methyltriethylsilane in a volume ratio of (1-3):1 to obtain a mixed solution C;
[0010] S4: Under constant temperature, the stirring rate of the mixed solution B is increased to 400 r / min, and the mixed solution C is added dropwise to the mixed solution B, the volume ratio of the mixed solution B to the mixed solution C is 1:1, and after the addition is completed, the temperature is raised to 40°C, and the mixture is stirred at a constant temperature for 2 to 3 hours. After the reaction is completed, the mixture is filtered and dried with hot air to obtain crude silica microspheres;
[0011] S5: Mix the silane coupling agent and the cationic surfactant in a mass ratio of 1:(1-2), grind in a ball mill at a speed of 500 r / min for 0.5 h to obtain a mixture, disperse the mixture in an ethanol solution with a solid-liquid mass ratio of 1:(3-5), and ultrasonicate for 0.5 h to obtain a mixed solution D;
[0012] S6: Wash the obtained crude silicon microspheres continuously, use mixed solution D to wash the crude silicon microspheres for the first time, put the silicon microspheres into the mixed solution D, ultrasonicate for 0.5h, centrifuge for the first time, wash with ethanol for the second time, centrifuge for the second time, wash with deionized water for the third time, centrifuge for the third time, filter, and blow with nitrogen at 70°C for 6h to obtain silicon microspheres.
[0013] Furthermore, the rate of slow dripping in S2 is 3s / drop.
[0014] Furthermore, the dripping rate in S4 is 1 s / drop.
[0015] Furthermore, the heating rate in S4 is 2°C / min.
[0016] Furthermore, the parameters of hot air drying in S4 are a drying temperature of 50 to 80° C. and a drying time of 3 to 5 minutes.
[0017] Furthermore, the silane coupling agent in S5 is one of silane coupling agent KH-560 and silane coupling agent KH-792.
[0018] Furthermore, the cationic surfactant in S5 is one of cetyltrimethylammonium bromide, cetyltrimethylammonium chloride, and octadecyltrimethylammonium chloride.
[0019] Furthermore, the mass fraction of the ethanol solution in S5 is 30-50%.
[0020] Furthermore, the parameters of the first centrifugal separation in S6 are a rotation speed of 10000-12000 rpm and a centrifugal time of 8-12 min, the parameters of the second centrifugal separation are a rotation speed of 10000-12000 rpm and a centrifugal time of 6-10 min, and the parameters of the third centrifugal separation are a rotation speed of 12000-14000 rpm and a centrifugal time of 3-5 min.
[0021] Furthermore, the purge flow rate of nitrogen in S6 is 20 m / s.
[0022] The continuous centrifugal washing method of the present invention shortens the production cycle and improves production efficiency. Impurities are effectively removed through multiple washing and centrifugal separation, and the purity of silicon microspheres is improved. Part of the washing liquid (such as ethanol and deionized water) used is a recovery solvent, which reduces environmental pollution and reduces production costs.
[0023] By precisely controlling the ratio of distilled water and isopropanol and the stirring conditions, a uniform and stable mixed solution A is obtained, which provides a good environment for subsequent reactions. Slowly dripping ammonia water and stirring at the same time ensures the uniform distribution of ammonia water in the mixed solution, which is conducive to the subsequent hydrolysis and condensation reaction of the silicon source. Tetraethyl orthosilicate and methyltriethylsilane are used as the main raw materials. Through hydrolysis and polycondensation reactions, they can form a skeleton structure of silicone resin, which provides a stable chemical basis for silicon microspheres and enhances their overall stability and durability. As raw materials, tetraethyl orthosilicate and methyltriethylsilane can be directly involved in the production process of silicon microspheres without complicated pretreatment or post-treatment steps, thereby simplifying the production process. Due to the high reactivity of the two raw materials, they can complete the reaction in a shorter time, thereby improving production efficiency. At the same time, their mixed use can also reduce energy consumption and waste discharge in the production process, which is conducive to environmental protection and sustainable development. The present invention also promotes the hydrolysis and condensation reactions of the silicon source by increasing the stirring rate and heating to a suitable temperature, and obtains a rough body of silicon microspheres with uniform structure. The mixed grinding and ultrasonic treatment of the silane coupling agent and the cationic surfactant ensures the uniform dispersion of the mixture in the ethanol solution, providing an effective washing solution for subsequent washing.
[0024] The first washing uses a mixed solution of silane coupling agent and cationic surfactant for ultrasonic washing, which effectively removes impurities and unreacted substances on the surface of the silicon microspheres.
[0025] The first washing with a mixed solution of silane coupling agent and cationic surfactant can enhance the balance of hydrophilicity and hydrophobicity on the surface of the silicon microspheres. The silane coupling agent has the characteristics of hydrophilicity at one end and hydrophobicity at the other end, which can improve the wettability of the surface of the silicon microspheres, making them both hydrophilic and hydrophobic. The cationic surfactant can further adjust the charge properties of the surface of the silicon microspheres, which is helpful for the dispersion and stability of the silicon microspheres in subsequent applications.
[0026] By washing with the mixed solution D, the charge distribution on the surface of the silicon microspheres is more uniform, reducing the possibility of agglomeration and precipitation. The chemical bonding between the silane coupling agent and the surface of the silicon microspheres also enhances the chemical stability of the silicon microspheres.
[0027] The positive ion part of the cationic surfactant can electrostatically interact with the negative ion part of the silane coupling agent to form an ion pair. At the same time, the cationic surfactant can also combine with the negative charge on the surface of the silica microspheres to further adjust the charge properties and wettability of the silica microsphere surface.
[0028] Through the combined action of silane coupling agent and cationic surfactant, the charge distribution on the surface of silica microspheres is more uniform and the wettability is improved.
[0029] The second washing is performed with an ethanol solution to further remove residual washing liquid and impurities; the third washing is performed with deionized water to ensure the purity and stability of the silicon microspheres; the present invention effectively removes moisture and residues on the surface of the silicon microspheres through multiple centrifugal washing and nitrogen purging, thereby obtaining dry and pure silicon microspheres.
[0030] Beneficial effects of the present invention:
[0031] The continuous centrifugal washing method of the present invention shortens the production cycle, improves production efficiency, effectively removes impurities through multiple washing and centrifugal separation, improves the purity of silicon microspheres, and uses part of the washing liquid as a recovery solvent, which reduces environmental pollution and reduces production costs. The first washing uses a mixed solution of a silane coupling agent and a cationic surfactant for ultrasonic washing, which effectively removes impurities and unreacted substances on the surface of the silicon microspheres; the second washing uses an ethanol solution for washing, which further removes residual washing liquid and impurities; the third washing uses deionized water for washing, which ensures the purity and stability of the silicon microspheres; the present invention effectively removes moisture and residues on the surface of the silicon microspheres through multiple centrifugal washing and nitrogen purging, and obtains dry and pure silicon microspheres. DETAILED DESCRIPTION
[0032] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in combination with the embodiments.
[0033] Example 1
[0034] S1: Distilled water and isopropanol were mixed in a volume ratio of 1:1, stirred at a speed of 150 r / min for 0.5 h, heated to 30°C while stirring, and stirred for 0.5 h after constant temperature to obtain a mixed solution A;
[0035] S2: slowly drop ammonia water with a concentration of 1 mol / L into the mixed solution A at a constant temperature, with a drop rate of 3 s / drop, and continue to stir the solution at a speed of 200 r / min while dropping, the volume ratio of the mixed solution A to the ammonia water is 1:0.5, and after the drop addition is completed, a mixed solution B is obtained;
[0036] S3: mixing tetraethyl orthosilicate and methyltriethylsilane in a volume ratio of 2:1 to obtain a mixed solution C;
[0037] S4: Under constant temperature, the stirring rate of the mixed solution B was increased to 400r / min, and the mixed solution C was added dropwise to the mixed solution B at a rate of 1s / drop, and the volume ratio of the mixed solution B to the mixed solution C was 1:1. After the addition was completed, the temperature was raised to 40°C, and the heating rate was 2°C / min. The mixture was stirred at a constant temperature for 3h. After the reaction was completed, the mixture was filtered and dried with hot air. The parameters of the hot air drying were a drying temperature of 60°C and a drying time of 4min to obtain crude silicon microspheres.
[0038] S5: Silane coupling agent KH-560 and cationic surfactant hexadecyltrimethylammonium bromide were mixed in a mass ratio of 1:1, and ground in a ball mill at a speed of 500 r / min for 0.5 h to obtain a mixture, and the mixture was dispersed in a 40% ethanol solution with a solid-liquid mass ratio of 1:4, and ultrasonicated for 0.5 h to obtain a mixed solution D;
[0039] S6: Wash the obtained crude silicon microspheres continuously, use mixed solution D to wash the crude silicon microspheres for the first time, put the silicon microspheres into the mixed solution D, ultrasonicate for 0.5h, centrifuge for the first time, the parameters of the first centrifugation are rotation speed 11000rpm, centrifugation time 10min, wash for the second time with ethanol, centrifuge for the second time, the parameters of the second centrifugation are rotation speed 12000rpm, centrifugation time 10min, wash for the third time with deionized water, centrifuge for the third time, the parameters of the third centrifugation are rotation speed 14000rpm, centrifugation time 5min, filter, use 70℃ nitrogen purge for 6h, the nitrogen purge flow rate is 20m / s, and silicon microspheres are obtained.
[0040] The yield of silicon microspheres prepared in this example is 95%, and the silicon microspheres have good sphericity and uniform particle size.
[0041] Example 2
[0042] S1: Distilled water and isopropanol were mixed in a volume ratio of 1:0.5, stirred at a speed of 150 r / min for 0.5 h, heated to 35°C while stirring, and continued to stir for 0.5 h after constant temperature to obtain a mixed solution A;
[0043] S2: slowly drop ammonia water with a concentration of 1 mol / L into the mixed solution A at a constant temperature, with a drop rate of 3 s / drop, and continue to stir the solution at a speed of 200 r / min while dropping, the volume ratio of the mixed solution A to the ammonia water is 1:1, and after the drop addition is completed, a mixed solution B is obtained;
[0044] S3: mixing tetraethyl orthosilicate and methyltriethylsilane in a volume ratio of 1:1 to obtain a mixed solution C;
[0045] S4: Under constant temperature, the stirring rate of the mixed solution B is increased to 400r / min, and the mixed solution C is added dropwise to the mixed solution B at a rate of 1s / drop, and the volume ratio of the mixed solution B to the mixed solution C is 1:1. After the addition is completed, the temperature is raised to 40°C, and the heating rate is 2°C / min. The mixture is stirred at a constant temperature for 2h. After the reaction is completed, the mixture is filtered and dried with hot air. The parameters of the hot air drying are a drying temperature of 50°C and a drying time of 5min to obtain crude silicon microspheres.
[0046] S5: Silane coupling agent KH-792 and cationic surfactant hexadecyltrimethylammonium chloride were mixed in a mass ratio of 1:2, and ground in a ball mill at a speed of 500 r / min for 0.5 h to obtain a mixture, and the mixture was dispersed in a 30% ethanol solution with a solid-liquid mass ratio of 1:3, and ultrasonicated for 0.5 h to obtain a mixed solution D;
[0047] S6: The obtained crude silicon microspheres are continuously washed, and the crude silicon microspheres are washed for the first time with mixed solution D, and the silicon microspheres are placed in mixed solution D, and ultrasonicated for 0.5h, and centrifuged for the first time. The parameters of the first centrifugation are a speed of 10000rpm and a centrifugation time of 12min. Ethanol is used for the second washing, and the second centrifugation is performed. The parameters of the second centrifugation are a speed of 10000rpm and a centrifugation time of 10min. Deionized water is used for the third washing, and the third centrifugation is performed. The parameters of the third centrifugation are a speed of 14000rpm and a centrifugation time of 3min. Filter, and use 70°C nitrogen to purge for 6h with a nitrogen purge flow rate of 20m / s to obtain silicon microspheres.
[0048] The yield of silicon microspheres prepared in this example is 93%, and the silicon microspheres have good sphericity and uniform particle size.
[0049] Example 3
[0050] S1: Distilled water and isopropanol were mixed in a volume ratio of 1:2, stirred at a speed of 150 r / min for 0.5 h, heated to 35°C while stirring, and stirred for 0.5 h after constant temperature to obtain a mixed solution A;
[0051] S2: slowly drop ammonia water with a concentration of 1 mol / L into the mixed solution A at a constant temperature, with a drop rate of 3 s / drop, and continue to stir the solution at a speed of 200 r / min while dropping, the volume ratio of the mixed solution A to the ammonia water is 1:1, and after the drop addition is completed, a mixed solution B is obtained;
[0052] S3: mixing tetraethyl orthosilicate and methyltriethylsilane in a volume ratio of 3:1 to obtain a mixed solution C;
[0053] S4: Under constant temperature, the stirring rate of the mixed solution B was increased to 400 r / min, and the mixed solution C was added dropwise to the mixed solution B at a rate of 1 s / drop, and the volume ratio of the mixed solution B to the mixed solution C was 1:1. After the addition was completed, the temperature was raised to 40°C, and the heating rate was 2°C / min. The mixture was stirred at a constant temperature for 2 h. After the reaction was completed, the mixture was filtered and dried with hot air. The parameters of the hot air drying were a drying temperature of 80°C and a drying time of 3 min to obtain crude silicon microspheres.
[0054] S5: Silane coupling agent KH-560 and cationic surfactant octadecyltrimethylammonium chloride were mixed in a mass ratio of 1:2, and ground in a ball mill at a speed of 500 r / min for 0.5 h to obtain a mixture, and the mixture was dispersed in a 50% ethanol solution with a solid-liquid mass ratio of 1:5, and ultrasonicated for 0.5 h to obtain a mixed solution D;
[0055] S6: Wash the obtained crude silicon microspheres continuously, use mixed solution D to wash the crude silicon microspheres for the first time, put the silicon microspheres into the mixed solution D, ultrasonicate for 0.5h, centrifuge for the first time, the parameters of the first centrifugation are rotation speed 12000rpm, centrifugation time 8min, wash for the second time with ethanol, centrifuge for the second time, the parameters of the second centrifugation are rotation speed 12000rpm, centrifugation time 6min, wash for the third time with deionized water, centrifuge for the third time, the parameters of the third centrifugation are rotation speed 12000rpm, centrifugation time 5min, filter, use 70℃ nitrogen purge for 6h, the nitrogen purge flow rate is 20m / s, and silicon microspheres are obtained.
[0056] The yield of silicon microspheres prepared in this example is 94%, and the silicon microspheres have good sphericity and uniform particle size.
[0057] Comparative Example 1
[0058] In this comparative example, only ethanol and deionized water are used for centrifugal washing in S6, and the remaining steps are consistent with those in Example 1.
[0059] The yield of silicon microspheres prepared in this comparative example was 93%, and the silicon microspheres were partially agglomerated and had uneven particle sizes.
[0060] Comparative Example 2
[0061] In this comparative example, no centrifugal separation is used after three washings in S6, and the remaining steps are consistent with those in Example 1.
[0062] The yield of silicon microspheres prepared in this example was 88%, and a large amount of silicon microspheres agglomerated and had large differences in particle sizes.
[0063] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.
Claims
1. A continuous centrifugal washing method for the production of silicon microspheres, characterized in that: The specific process of the method is as follows: S1: Distilled water and isopropanol were mixed in a volume ratio of 1:(0.5-2), stirred at a speed of 150 r / min for 0.5 h, heated to 30-35° C. while stirring, and continued to stir for 0.5 h after constant temperature to obtain a mixed solution A; S2: slowly drop ammonia water with a concentration of 1 mol / L into the mixed solution A at a constant temperature, and continue to stir the solution at a speed of 200 r / min while dropping, the volume ratio of the mixed solution A to the ammonia water is 1:(0.5-1), and after the dropwise addition is completed, a mixed solution B is obtained; S3: mixing tetraethyl orthosilicate and methyltriethylsilane in a volume ratio of (1-3):1 to obtain a mixed solution C; S4: Under constant temperature, the stirring rate of the mixed solution B is increased to 400 r / min, and the mixed solution C is added dropwise to the mixed solution B, the volume ratio of the mixed solution B to the mixed solution C is 1:1, and after the addition is completed, the temperature is raised to 40°C, and the mixture is stirred at a constant temperature for 2 to 3 hours. After the reaction is completed, the mixture is filtered and dried with hot air to obtain crude silica microspheres; S5: Mix the silane coupling agent and the cationic surfactant in a mass ratio of 1:(1-2), grind in a ball mill at a speed of 500 r / min for 0.5 h to obtain a mixture, disperse the mixture in an ethanol solution with a solid-liquid mass ratio of 1:(3-5), and ultrasonicate for 0.5 h to obtain a mixed solution D; S6: Wash the obtained crude silicon microspheres continuously, use mixed solution D to wash the crude silicon microspheres for the first time, put the silicon microspheres into the mixed solution D, ultrasonicate for 0.5h, centrifuge for the first time, wash with ethanol for the second time, centrifuge for the second time, wash with deionized water for the third time, centrifuge for the third time, filter, and blow with nitrogen at 70°C for 6h to obtain silicon microspheres.
2. The continuous centrifugal washing method for producing silicon microspheres according to claim 1, characterized in that: The rate of slow dripping in S2 is 3s / drop.
3. The continuous centrifugal washing method for producing silicon microspheres according to claim 1, characterized in that: The dropping rate in S4 is 1 s / drop.
4. The continuous centrifugal washing method for producing silicon microspheres according to claim 1, characterized in that: The heating rate in S4 is 2°C / min.
5. The continuous centrifugal washing method for producing silicon microspheres according to claim 1, characterized in that: The parameters of hot air drying in S4 are a drying temperature of 50 to 80° C. and a drying time of 3 to 5 minutes.
6. The continuous centrifugal washing method for producing silicon microspheres according to claim 1, characterized in that: The silane coupling agent in S5 is one of silane coupling agent KH-560 and silane coupling agent KH-792.
7. The continuous centrifugal washing method for producing silicon microspheres according to claim 1, characterized in that: The cationic surfactant in S5 is one of cetyltrimethylammonium bromide, cetyltrimethylammonium chloride and octadecyltrimethylammonium chloride.
8. The continuous centrifugal washing method for producing silicon microspheres according to claim 1, characterized in that: The mass fraction of the ethanol solution in S5 is 30-50%.
9. The continuous centrifugal washing method for producing silicon microspheres according to claim 1, characterized in that: The parameters of the first centrifugal separation in S6 are a rotation speed of 10000-12000 rpm and a centrifugal time of 8-12 min, the parameters of the second centrifugal separation are a rotation speed of 10000-12000 rpm and a centrifugal time of 6-10 min, and the parameters of the third centrifugal separation are a rotation speed of 12000-14000 rpm and a centrifugal time of 3-5 min.
10. The continuous centrifugal washing method for producing silicon microspheres according to claim 1, characterized in that: The purge flow rate of nitrogen in S6 is 20 m / s.