A method for efficiently preparing micron-sized silica microspheres using water glass via reverse-phase suspension dispersion.

Abstract

This invention discloses a method for efficiently preparing micron-sized silica microspheres using water glass via reverse-phase suspension dispersion. Utilizing the principle of preparing a weak acid from a strong acid, different types of silicic acid compounds and different organic phases are mixed in proportion, and different types / concentrations of acid are added dropwise under high-speed dispersion conditions to initiate the reaction. After silica microspheres precipitate, dispersion continues for a period of time. Following precipitation, washing, and drying, monodisperse micron-sized amorphous silica microspheres of different particle sizes are obtained. The water glass used in this invention is low-cost, eliminates the need for emulsifiers, greatly simplifies the operation process, and allows for the recycling of the organic phase. The entire preparation process is simple, energy-efficient, cost-effective, and environmentally friendly. The micron-sized silica microspheres prepared by this invention contain a large number of hydroxyl groups, have a large specific surface area, allow for particle size control, and exhibit high sphericity. This method has significant advantages and promising applications in the preparation of micron-sized silica microspheres.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of silica microsphere preparation, and particularly relates to a method for efficiently preparing micron-sized silica microspheres by reverse-phase suspension dispersion of water glass. BACKGROUND

[0002] Silica microspheres exhibit excellent mechanical, thermal, chemical (especially acid resistance) and biological stability, and composite materials made of silica microspheres are used in many monitoring fields, including detection of biomolecules, ions and compounds. In particular, micron-sized silica microspheres have a wide range of applications and can be used as reinforcing materials in different media to improve the strength, hardness, chemical stability, wear resistance, corrosion resistance and weather resistance of the matrix. For example, monodisperse silica microspheres are widely used in display panels to stabilize the gap space in liquid crystals and act as a skeleton. In addition, silica microspheres have large pore sizes, low toxicity and high specific surface area, making them ideal adsorbents and chemical carriers. Moreover, the content of hydroxyl groups on the surface of amorphous silica is very high, which provides multiple possibilities for surface modification.

[0003] Currently, the methods for preparing micron-sized silica microspheres mainly include physical methods and chemical methods. The physical methods include mechanical grinding, spray drying and high-temperature spheroidization, while the chemical methods include template method, vapor phase method and precipitation method. In the physical method, irregularly shaped silica raw materials are converted into spheres through a series of physical methods. In the chemical method, organosilicon or water glass is used as raw material to obtain silica microspheres through a series of chemical modifications. Compared with the physical method, the main advantage of the chemical synthesis process is low energy consumption and high purity. However, most chemical synthesis methods use organosilicon such as tetraethyl orthosilicate as the silicon source, which is expensive and the byproduct of the reaction is organic matter, which increases the cost of post-reaction treatment and complicates downstream processing. Compared with the precipitation method, the evaporation method and the template method use inexpensive water glass as the silicon source, but they also have problems such as complex ion exchange process and poor product quality. Therefore, there is an urgent need to develop a low-cost, low-energy process to synthesize micron-sized silica microspheres to achieve the goal of "low carbon and energy saving".

[0004] Currently, the process of synthesizing silica microspheres from water glass as raw material is rarely seen, and almost all silica microspheres in the industry are synthesized from tetraethyl orthosilicate (TEOS), because the silica microspheres produced by this process have good sphericity, low density and easy size control. Although the synthesis of silica microspheres from water glass has the advantages of low raw material cost, low production rate and environmental protection, etc., but because the silica microspheres synthesized by this technology have high agglomeration, the spherical particles cannot be monodispersed, and emulsifiers are needed, and the organic phase after preparation is difficult to recycle, so it is very difficult to industrialize. Therefore, it is necessary to develop a high-efficiency preparation process of silica microspheres with water glass as raw material, which greatly simplifies the operation process and realizes the recycling of the organic phase. SUMMARY

[0005] To solve the problems in the prior art, the present application provides a method for efficiently preparing micron-sized silica microspheres by reverse-phase suspension dispersion using water glass. The present application can obtain micron-sized silica microspheres with excellent sphericity, controllable particle size and pore volume, and can realize the recycling of the organic phase after preparation. The entire preparation process is simple to operate, low in energy consumption, low in cost and environmentally friendly, solving the problems mentioned in the background art.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solution: a method for efficiently preparing micron-sized silica microspheres by reverse-phase suspension dispersion using water glass, comprising the following steps:

[0007] S1, mixing liquid water glass and organic phase in a certain proportion, and dispersing and aging at high speed to form a reaction precursor;

[0008] S2: adding an acidic solution to the dispersed precursor under high-speed stirring;

[0009] S3: continuing to disperse and age for a period of time after the silica microspheres are precipitated;

[0010] S4: precipitating, washing and drying to obtain monodispersed micron-sized silica microspheres.

[0011] Preferably, the liquid water glass in step S1 comprises sodium water glass Na2O·nSiO2, potassium water glass K2O·nSiO2 and / or potassium / sodium water glass (K / Na)2O·nSiO2 with different modulus n, wherein the different modulus n ranges from 2.3 to 3.3.

[0012] Preferably, the organic phase in step S1 is a mixed liquid of hydrocarbons contained in animals and plants, including one or more of the following: machine oil, silicone oil, vacuum pump oil, petroleum, gasoline, kerosene, peanut oil, soybean oil or sunflower seed oil.

[0013] Preferably, the volume ratio of liquid water glass to organic phase in step S1 is 1:1-200.

[0014] Preferably, the volume ratio of liquid water glass to organic phase in step S1 is 1:3-50.

[0015] Preferably, the dispersion speed in step S1 is 100-5000 r / min, and the aging time is 1-60 min.

[0016] Preferably, the dispersion speed in step S1 is 500-3000 r / min, and the aging time is 5-40 min.

[0017] Preferably, the mass percentage concentration of the acidic liquid in step S2 is 1% to pure solvent, and the dropping speed is 0.05-100 mL / min. -1 The acidic liquid is acetic acid, citric acid, malic acid, formic acid, acetic acid propionic acid, carbonic acid, sulfuric acid, hydrochloric acid, phosphoric acid, ammonium chloride or ethyl acetate.

[0018] Preferably, the mass percentage concentration of the acidic liquid in step S2 is 5% to 60%, and the dropping speed is 0.5-30 mL / min. -1

[0019] Preferably, the dispersion speed in step S3 is 100-5000 r / min, and the dispersion time is 1-60 min.

[0020] Preferably, the dispersion speed in step S3 is 500-3000 r / min, and the dispersion time is 10-30 min.

[0021] Preferably, the drying temperature in step S4 is 20-200°C, and the drying time is 20 min-72 h.

[0022] Preferably, the drying temperature in step S4 is 80-120°C, and the drying time is 20 min-48 h.

[0023] Preferably, the monodisperse micron-sized amorphous silica microspheres have a particle size of 1-500 μm, a specific surface area of 5-800 m 2 / g, and a pore volume of 0.1726-0.43 cm 3 / g.

[0024] Preferably, the monodisperse micron-sized amorphous silica microspheres have a particle size of 20-300 μm, a specific surface area of 100-400 m 2 / g, and a pore volume of 0.17-0.2624 cm 3 / g.

[0025] ​Preferably, in the method for preparing micron-sized silica microspheres, no emulsifier is required, enabling the recycling of the organic phase. After 30 to 50 cycles, the prepared monodisperse micron-sized amorphous silica microspheres retain a particle size of 1 to 500 μm and a specific surface area of ​​5 to 800 m². 2 / g, pore volume 0.17~0.43cm³ 3 / g.

[0026] The beneficial effects of this invention are as follows: Addressing the problems existing in current methods for generating silica microspheres using water glass as a raw material via precipitation, this invention develops a method for efficiently preparing micron-sized silica microspheres using water glass through reverse-phase suspension dispersion technology. It employs the principle of strong acid displacing weak acid, utilizing the characteristic that water glass reacts under acidic conditions to generate silicic acid, and that supersaturated silicic acid precipitates silica. The specific operation is carried out according to the following steps: different types of silicic acid compounds and different organic phases are mixed in proportion; different types / concentrations of acid are added dropwise under high-speed dispersion conditions to react; after silica microspheres precipitate, dispersion continues for a period of time; and after precipitation, washing, and drying, monodisperse micron-sized amorphous silica microspheres of different particle sizes are obtained. Compared with current preparation technologies, this invention's method for preparing silica has: a simpler process flow, one-step sphere formation, low equipment requirements, no need for any high-temperature conditions, significantly reduced energy consumption, and inexpensive raw materials (ten times cheaper than currently commercially available tetraethyl orthosilicate). It also allows for the recycling of the organic phase, making the entire preparation process green and environmentally friendly. The silica microspheres prepared by this invention are monodisperse, have good sphericity, large pore volume and specific surface area, and high yield; the particle size is controllable (1-400 μm) and the particle size distribution is uniform; the pore volume is large and the pore size distribution is uniform; and they have excellent properties such as high strength, high temperature resistance, corrosion resistance and chemical stability. This method has great advantages and application prospects in the preparation of silica microspheres. Attached Figure Description

[0027] Figure 1 Examples 1-4 are optical microscope images of silica microspheres prepared using water glass of different moduli as raw materials;

[0028] Figure 2 Examples 1-4 show the particle size distribution of silica microspheres prepared using water glass of different moduli as raw materials;

[0029] Figure 3 Examples 5-6 are optical microscope images of silica microspheres prepared using potassium and potassium / sodium water glass as raw materials;

[0030] Figure 4 Examples 7-10 are optical microscope images of the preparation of silica microspheres in rapeseed oil, soybean oil, peanut oil and dimethyl silicone oil media;

[0031] Figure 5Examples 11-14 are optical microscope images of silica microspheres prepared by adding carbonic acid, sulfuric acid, hydrochloric acid and hydrochloric acid / sulfuric acid mixture as raw materials;

[0032] Figure 6 Examples 15-16 are optical microscope images of silica microspheres prepared from engine oil media after the second and fifth cycles;

[0033] Figure 7 Examples 1, 2, 6, and 10 are X-ray diffraction patterns of silica microspheres prepared under different process parameters;

[0034] Figure 8 Comparative Example 1 shows an optical microscope image of silica microspheres prepared with the addition of an emulsifier;

[0035] Figure 9 This is a state diagram of the final phase of the system after the reaction of Comparative Example 1 and Example 1 is completed. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Example 1:

[0038] (1) Add 10 mL of sodium water glass slurry with a modulus of 2.3 to 500 mL of machine oil and mix evenly. Disperse at a dispersion speed of 500 r / min for 40 min to make the system a homogeneous slurry.

[0039] (2) A 25% acetic acid solution was added dropwise at a rate of 2 mL / min to the slurry in step (1) with a dispersion rate of 500 r / min;

[0040] (3) After the acid solution has finished dripping, continue to stir and disperse (age) the machine oil and the obtained product from step (2) at a dispersion speed of 500 r / min for 30 min;

[0041] (4) Filter the oil and the product obtained in step (3) to obtain silica microspheres;

[0042] (5) Place the silica microspheres from step (4) in water and wash away the residual machine oil on the surface of the microspheres;

[0043] (6) The silica microspheres obtained in step (5) were dried in an oven at 85°C for 48 hours;

[0044] Upon examination, the microspheres were analyzed using optical microscopy and their size distribution photographs, as shown below. Figure 1 and Figure 2 As shown, its average particle size is 91.28 μm and its specific surface area is 243.83 m². 2 / g, pore volume is 0.2675cm³ 3 / g. X-ray diffraction pattern as shown in the image. Figure 7 As shown.

[0045] Example 2:

[0046] (1) Add 10 mL of sodium water glass slurry with a modulus of 2.3 to 30 mL of machine oil and mix evenly. Disperse at a dispersion speed of 3000 r / min for 5 min to make the system a homogeneous slurry.

[0047] (2) A 25% acetic acid solution was added dropwise at a rate of 2 mL / min to the slurry in step (1) with a dispersion rate of 3000 r / min;

[0048] (3) After the acid solution has finished dripping, continue to stir and disperse (age) the machine oil and the obtained product from step (2) at a dispersion speed of 3000 r / min for 10 min;

[0049] (4) Filter the oil and the product obtained in step (3) to obtain silica microspheres;

[0050] (5) Place the silica microspheres from step (4) in water and wash away the residual machine oil on the surface of the microspheres;

[0051] (6) The silica microspheres obtained in step (5) are dried in an oven at 120°C for 20 min;

[0052] Upon examination, the microspheres were analyzed using optical microscopy and their size distribution photographs, as shown below. Figure 1 As shown, its average particle size is 83.35 μm and its specific surface area is 234.83 m². 2 / g, pore volume is 0.1726cm³ 3 / g.

[0053] Example 3:

[0054] (1) Add 10 mL of sodium water glass slurry with a modulus of 3.3 to 100 mL of machine oil and mix evenly. Disperse at a dispersion speed of 2500 r / min for 20 min to make the system a homogeneous slurry.

[0055] (2) A 5% acetic acid solution was added dropwise at a rate of 30 mL / min to the slurry in step (1) with a dispersion rate of 2500 r / min;

[0056] (3) After the acid solution has finished dripping, continue to stir and disperse (age) the machine oil and the obtained product from step (2) at a dispersion speed of 2500 r / min for 15 min;

[0057] (4) Filter the oil and the product obtained in step (3) to obtain silica microspheres;

[0058] (5) Place the silica microspheres from step (4) in water and wash away the residual machine oil on the surface of the microspheres;

[0059] (6) The silica microspheres obtained in step (5) are dried in an oven at 100°C for 50 min;

[0060] Upon examination, the microspheres were analyzed using optical microscopy and their size distribution photographs, as shown below. Figure 1 As shown, its average particle size is 114.51 μm and its specific surface area is 176.4867 m². 2 / g, pore volume is 0.432cm³ 3 / g.

[0061] Example 4:

[0062] (1) Add 10 mL of sodium water glass slurry with a modulus of 3.3 to 100 mL of machine oil and mix evenly. Disperse at a dispersion speed of 2500 r / min for 20 min to make the system a homogeneous slurry.

[0063] (2) A 60% acetic acid solution was added dropwise at a rate of 0.5 mL / min to the slurry in step (1) with a dispersion rate of 2500 r / min;

[0064] (3) After the acid solution has finished dripping, continue to stir and disperse (age) the machine oil and the obtained product from step (2) at a dispersion speed of 2500 r / min for 15 min;

[0065] (4) Filter the oil and the product obtained in step (3) to obtain silica microspheres;

[0066] (5) Place the silica microspheres from step (4) in water and wash away the residual machine oil on the surface of the microspheres;

[0067] (6) The silica microspheres obtained in step (5) were dried in an oven at 90°C for 24 hours;

[0068] Upon examination, the microspheres were analyzed using optical microscopy and their size distribution photographs, as shown below. Figure 1 As shown, its average particle size is 104.81 μm and its specific surface area is 40.57 m². 2 / g, pore volume is 0.2624cm³ 3 / g.

[0069] Example 5:

[0070] (1) Add 10 mL of potassium water glass slurry with a modulus of 2.3 to 100 mL of machine oil and mix evenly. Disperse at a dispersion speed of 2500 r / min for 20 min to make the system a homogeneous slurry.

[0071] (2) A 5% acetic acid solution was added dropwise at a rate of 2 mL / min to the slurry in step (1) with a dispersion rate of 2500 r / min;

[0072] (3) After the acid solution has finished dripping, continue to stir and disperse (age) the machine oil and the obtained product from step (2) at a dispersion speed of 2500 r / min for 15 min;

[0073] (4) Filter the oil and the product obtained in step (3) to obtain silica microspheres;

[0074] (5) Place the silica microspheres from step (4) in water and wash away the residual machine oil on the surface of the microspheres;

[0075] (6) The silica microspheres obtained in step (5) were dried in an oven at 85°C for 48 hours;

[0076] Upon examination, the microspheres were analyzed using optical microscopy and their size distribution photographs, as shown below. Figure 3 As shown, due to the low viscosity of potassium silicate, it is excessively dispersed, resulting in severe agglomeration of silica.

[0077] Example 6:

[0078] (1) Add 10 mL of potassium / sodium water glass slurry with a modulus of 2.3 to 100 mL of machine oil and mix evenly. Disperse at a dispersion speed of 2500 r / min for 20 min to make the system a homogeneous slurry.

[0079] (2) A 5% acetic acid solution was added dropwise at a rate of 2 mL / min to the slurry in step (1) with a dispersion rate of 2500 r / min;

[0080] (3) After the acid solution has finished dripping, continue to stir and disperse (age) the machine oil and the obtained product from step (2) at a dispersion speed of 2500 r / min for 15 min;

[0081] (4) Filter the oil and the product obtained in step (3) to obtain silica microspheres;

[0082] (5) Place the silica microspheres from step (4) in water and wash away the residual machine oil on the surface of the microspheres;

[0083] (6) The silica microspheres obtained in step (5) were dried in an oven at 85°C for 48 hours;

[0084] The microspheres were examined and the optical microscope image is shown below. Figure 3 As shown, the X-ray diffraction pattern is as follows: Figure 7 As shown.

[0085] Example 7:

[0086] (1) Add 10 mL of potassium / sodium water glass slurry with a modulus of 2.3 to 100 mL of soybean oil and mix evenly. Disperse at a dispersion speed of 2500 r / min for 20 min to make the system a homogeneous slurry.

[0087] (2) A 5% acetic acid solution was added dropwise at a rate of 2 mL / min to the slurry in step (1) with a dispersion rate of 2500 r / min;

[0088] (3) After the acid solution has finished dripping, continue to stir and disperse (age) the soybean oil and the obtained product from step (2) at a dispersion speed of 2500 r / min for 15 min;

[0089] (4) Filter the soybean oil and the resulting product from step (3) to obtain silica microspheres;

[0090] (5) Place the silica microspheres from step (4) in water and wash away the soybean oil residue on the surface of the microspheres.

[0091] (6) The silica microspheres obtained in step (5) were dried in an oven at 85°C for 48 hours;

[0092] The microspheres were examined and the optical microscope image is shown below. Figure 4 As shown.

[0093] Example 8:

[0094] (1) Add 10 mL of potassium / sodium water glass slurry with a modulus of 2.3 to 100 mL of peanut oil and mix evenly. Disperse at a dispersion speed of 2500 r / min for 20 min to make the system a homogeneous slurry.

[0095] (2) A 5% acetic acid solution was added dropwise at a rate of 2 mL / min to the slurry in step (1) with a dispersion rate of 2500 r / min;

[0096] (3) After the acid solution has been dripped out, continue to stir and disperse (age) the peanut oil and the obtained product from step (2) at a dispersion speed of 2500 r / min for 15 min;

[0097] (4) Filter the soybean oil and the resulting product from step (3) to obtain silica microspheres;

[0098] (5) Place the silica microspheres from step (4) in water and wash away the peanut oil residue on the surface of the microspheres;

[0099] (6) The silica microspheres obtained in step (5) are dried in an oven at 110°C for 20 min;

[0100] The microspheres were examined and the optical microscope image is shown below. Figure 4 As shown.

[0101] Example 9:

[0102] (1) Add 10 mL of potassium / sodium water glass slurry with a modulus of 2.3 to 100 mL of sunflower seed oil and mix evenly. Disperse at a dispersion speed of 2500 r / min for 20 min to make the system a homogeneous slurry.

[0103] (2) A 5% acetic acid solution was added dropwise at a rate of 2 mL / min to the slurry in step (1) with a dispersion rate of 2500 r / min;

[0104] (3) After the acid solution has been dripped out, continue to stir and disperse (age) the sunflower seed oil and the obtained product from step (2) at a dispersion speed of 2500 r / min for 15 min.

[0105] (4) Filter the sunflower seed oil and the obtained product from step (3) to obtain silica microspheres;

[0106] (5) Place the silica microspheres from step (4) in water and wash away the sunflower seed oil residue on the surface of the microspheres.

[0107] (6) The silica microspheres obtained in step (5) were dried in an oven at 85°C for 48 hours;

[0108] The microspheres were examined and the optical microscope image is shown below. Figure 4 As shown.

[0109] Example 10:

[0110] (1) Add 10 mL of potassium / sodium water glass slurry with a modulus of 2.3 to 100 mL of methyl silicone oil and mix evenly. Disperse at a dispersion speed of 2500 r / min for 20 min to make the system a homogeneous slurry.

[0111] (2) A 5% acetic acid solution was added dropwise at a rate of 2 mL / min to the slurry in step (1) with a dispersion rate of 2500 r / min;

[0112] (3) After the acid solution has been dripped out, the methyl silicone oil and the obtained product from step (2) are stirred and dispersed (aged) at a dispersion speed of 2500 r / min for 15 min.

[0113] (4) Filter the soybean oil and the resulting product from step (3) to obtain silica microspheres;

[0114] (5) Place the silica microspheres from step (4) in water and wash away the residual methyl silicone oil on the surface of the microspheres;

[0115] (6) The silica microspheres obtained in step (5) are dried in an oven at 105°C for 2 hours;

[0116] The microspheres were examined and the optical microscope image is shown below. Figure 4 As shown, the X-ray diffraction pattern is as follows: Figure 7 As shown.

[0117] Example 11:

[0118] (1) Add 10 mL of sodium water glass slurry with a modulus of 2.3 to 30 mL of machine oil and mix evenly. Disperse at a dispersion speed of 3000 r / min for 5 min to make the system a homogeneous slurry.

[0119] (2) A 25% carbonic acid solution is dropped into the slurry from step (1) at a rate of 2 mL / min and a dispersion rate of 3000 r / min.

[0120] (3) After the acid solution has finished dripping, continue to stir and disperse (age) the machine oil and the obtained product from step (2) at a dispersion speed of 3000 r / min for 10 min;

[0121] (4) Filter the oil and the product obtained in step (3) to obtain silica microspheres;

[0122] (5) Place the silica microspheres from step (4) in water and wash away the residual machine oil on the surface of the microspheres;

[0123] (6) The silica microspheres obtained in step (5) are dried in an oven at 120°C for 20 min;

[0124] Upon examination, the microspheres were analyzed using optical microscopy and their size distribution photographs, as shown below. Figure 5 As shown, Example 12:

[0125] (1) Add 10 mL of sodium water glass slurry with a modulus of 3.3 to 100 mL of machine oil and mix evenly. Disperse at a dispersion speed of 2500 r / min for 20 min to make the system a homogeneous slurry.

[0126] (2) A 25% sulfuric acid solution was added dropwise at a rate of 0.5 mL / min to the slurry in step (1) with a dispersion rate of 2500 r / min;

[0127] (3) After the acid solution has finished dripping, continue to stir and disperse (age) the machine oil and the obtained product from step (2) at a dispersion speed of 2500 r / min for 15 min;

[0128] (4) Filter the oil and the product obtained in step (3) to obtain silica microspheres;

[0129] (5) Place the silica microspheres from step (4) in water and wash away the residual machine oil on the surface of the microspheres;

[0130] (6) The silica microspheres obtained in step (5) were dried in an oven at 90°C for 24 hours;

[0131] Upon examination, the microspheres were analyzed using optical microscopy and their size distribution photographs, as shown below. Figure 5 As shown, Example 13:

[0132] (1) Add 10 mL of sodium water glass slurry with a modulus of 2.3 to 500 mL of machine oil and mix evenly. Disperse at a dispersion speed of 500 r / min for 40 min to make the system a homogeneous slurry.

[0133] (2) A 5% hydrochloric acid solution was added dropwise at a rate of 2 mL / min to the slurry in step (1) with a dispersion rate of 500 r / min.

[0134] (3) After the acid solution has finished dripping, continue to stir and disperse (age) the machine oil and the obtained product from step (2) at a dispersion speed of 500 r / min for 30 min;

[0135] (4) Filter the oil and the product obtained in step (3) to obtain silica microspheres;

[0136] (5) Place the silica microspheres from step (4) in water and wash away the residual machine oil on the surface of the microspheres;

[0137] (6) The silica microspheres obtained in step (5) were dried in an oven at 85°C for 48 hours;

[0138] Upon examination, the microspheres were analyzed using optical microscopy and their size distribution photographs, as shown below. Figure 5 As shown.

[0139] Example 14:

[0140] (1) Add 10 mL of sodium water glass slurry with a modulus of 3.3 to 100 mL of machine oil and mix evenly. Disperse at a dispersion speed of 2500 r / min for 20 min to make the system a homogeneous slurry.

[0141] (2) A 5% hydrochloric acid / sulfuric acid mixed solution was added dropwise at a rate of 2 mL / min to the slurry of step (1) with a dispersion rate of 2500 r / min;

[0142] (3) After the acid solution has finished dripping, continue to stir and disperse (age) the machine oil and the obtained product from step (2) at a dispersion speed of 2500 r / min for 15 min;

[0143] (4) Filter the oil and the product obtained in step (3) to obtain silica microspheres;

[0144] (5) Place the silica microspheres from step (4) in water and wash away the residual machine oil on the surface of the microspheres;

[0145] (6) The silica microspheres obtained in step (5) were dried in an oven at 85°C for 48 hours;

[0146] The microspheres were examined and the optical microscope image is shown below. Figure 5 As shown.

[0147] Example 15:

[0148] (1) Add 10 mL of sodium water glass slurry with a modulus of 3.3 to 100 mL of machine oil (which has been recycled twice) and mix evenly. Disperse at a dispersion speed of 2500 r / min for 20 min to make the system a homogeneous slurry.

[0149] (2) A 5% acetic acid solution was added dropwise at a rate of 30 mL / min to the slurry in step (1) with a dispersion rate of 2500 r / min;

[0150] (3) After the acid solution has finished dripping, continue to stir and disperse (age) the machine oil and the obtained product from step (2) at a dispersion speed of 2500 r / min for 15 min;

[0151] (4) Filter the oil and the product obtained in step (3) to obtain silica microspheres;

[0152] (5) Place the silica microspheres from step (4) in water and wash away the residual machine oil on the surface of the microspheres;

[0153] (6) The silica microspheres obtained in step (5) are dried in an oven at 100°C for 50 min;

[0154] Upon testing, the microspheres prepared from the oil medium after the second cycle were observed to have optical microscopy and particle size distribution images as follows: Figure 6 As shown.

[0155] Example 16:

[0156] (1) Add 10 mL of sodium water glass slurry with a modulus of 3.3 to 100 mL of machine oil (which has been recycled five times) and mix evenly. Disperse at a dispersion speed of 2500 r / min for 20 min to make the system a homogeneous slurry.

[0157] (2) A 5% acetic acid solution was added dropwise at a rate of 30 mL / min to the slurry in step (1) with a dispersion rate of 2500 r / min;

[0158] (3) After the acid solution has finished dripping, continue to stir and disperse (age) the machine oil and the obtained product from step (2) at a dispersion speed of 2500 r / min for 15 min;

[0159] (4) Filter the oil and the product obtained in step (3) to obtain silica microspheres;

[0160] (5) Place the silica microspheres from step (4) in water and wash away the residual machine oil on the surface of the microspheres;

[0161] (6) The silica microspheres obtained in step (5) are dried in an oven at 100°C for 50 min;

[0162] After testing, the microspheres prepared from the oil medium after the fifth cycle were observed to have optical microscopy and particle size distribution images as follows: Figure 6 As shown.

[0163] Comparative Example 1

[0164] (1) Add 10 mL of sodium water glass slurry with a modulus of 2.3 to 500 mL of machine oil and mix evenly. Disperse at a dispersion speed of 500 r / min for 40 min to make the system a homogeneous slurry.

[0165] (2) Add 5g of dehydrated sorbitol fatty acid ester (span-80) to the slurry in step (1) and continue to disperse for 10min;

[0166] (3) Add a 25% acetic acid solution by mass to the slurry of step (2) at a dropping rate of 2 mL / min and a dispersion rate of 500 r / min;

[0167] (4) After the acid solution has finished dripping, continue to stir and disperse (age) the machine oil and the obtained product from step (3) at a dispersion speed of 500 r / min for 30 min;

[0168] (5) Filter the oil and the product obtained in step (4) to obtain silica microspheres;

[0169] (6) Place the silica microspheres from step (5) in water and wash away the residual machine oil on the surface of the microspheres;

[0170] (7) The silica microspheres obtained in step (6) were dried in an oven at 85°C for 48 hours;

[0171] The experimental conditions of Example 1 were used, with no other variables changed, except for the addition of an emulsifier (Span-80). The two experimental groups were compared, as follows: Figure 8 As shown, the emulsifier exacerbates the aggregation of microspheres, forming spherical clusters. Furthermore, the yield of silica microspheres in the w / o system is only 53%, while the yield in Example 1 reaches 86%. After adding the emulsifier, the final phase is an emulsion, as shown... Figure 9 As shown in Comparative Example 1; and without emulsifier, as Figure 9 As shown in Example 1, the aqueous phase and organic phase can be separated and reused. After repeated cycles of the experiment, the production of silica microspheres can still be achieved.

[0172] In summary, addressing the problems of current precipitation methods using water glass as a raw material to generate silica microspheres, this application develops a method for preparing micron-sized amorphous silica microspheres using water glass as a raw material. This method utilizes the characteristic that water glass reacts under acidic conditions to generate silicic acid, and the supersaturated silicic acid precipitates silica. The specific operation is carried out according to the following steps: First, water glass and an organic phase are stirred and dispersed at high speed in a certain proportion to form a uniform reaction precursor solution. Then, an acidic solution is added dropwise to the solution under high-speed stirring to react and precipitate silica microspheres. Finally, after precipitation, washing, and drying, micron-sized silica microspheres are obtained. Compared with current preparation technologies, this invention's method for preparing silica has the following advantages: the entire process is simple, spheres are formed in one step, equipment requirements are low, no high-temperature conditions are required, significantly reducing energy consumption in the preparation process; the raw material is inexpensive, ten times cheaper than the currently commercially available tetraethyl orthosilicate; solid waste (the organic phase can be reused) can be recycled; and the entire preparation process is green and environmentally friendly. Furthermore, the silica microspheres prepared according to this invention are monodisperse, have good sphericity, large pore volume and specific surface area, and high yield; the particle size is controllable (5-300 μm) and the particle size distribution is uniform; the pore volume is large and the pore size distribution is uniform; and they have excellent properties such as high strength, high temperature resistance, corrosion resistance and chemical stability. This method has great advantages and application prospects in the preparation of silica microspheres.

[0173] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for efficiently preparing micron-sized silica microspheres by reverse-phase suspension dispersion using water glass, characterized by, The method comprises the following steps: S1, mixing liquid water glass and organic phase according to a certain proportion, high-speed dispersion aging to form a reaction precursor; the organic phase is a mixed liquid of hydrocarbons contained in animals and plants, including one or more of the following: engine oil, silicone oil, vacuum pump oil, petroleum oil, gasoline, kerosene, peanut oil, soybean oil or sunflower seed oil; S2, adding an acidic solution to the high-speed stirring dispersion precursor; S3, continuing to disperse and age for a period of time after the silica microspheres are precipitated; S4, precipitation, washing and drying to obtain monodisperse micron-sized silica microspheres.

2. The method for preparing micron-sized silica microspheres by reverse-phase suspension dispersion with water glass according to claim 1, characterized in that: The liquid water glass in step S1 comprises sodium water glass Na2O•nSiO2, potassium water glass K2O•nSiO2 and / or potassium / sodium water glass (K / Na)2O•nSiO2 with different modulus n, wherein the modulus n ranges from 2.3 to 3.

3. 3.The method for preparing micron-sized silica microspheres by reverse-phase suspension dispersion with water glass according to claim 1, characterized in that: The volume ratio of the liquid water glass to the organic phase in step S1 is 1:1-200.

4. The method for preparing micron-sized silica microspheres by reverse-phase suspension dispersion with water glass according to claim 1, characterized in that: The dispersion speed in step S1 is 100-5000 r / min, and the aging time is 1-60 min.

5. The method for preparing micron-sized silica microspheres by reverse-phase suspension dispersion with water glass according to claim 1, characterized in that: The mass percentage concentration of the acid liquid in step S2 is 5% to 60%, and the dropping speed is 0.05-100 mL / min -1 The acid liquid is acetic acid, citric acid, malic acid, formic acid, acetic acid, propionic acid, carbonic acid, sulfuric acid, hydrochloric acid, phosphoric acid, ammonium chloride or ethyl acetate. 6.The method for preparing micron-sized silica microspheres by reverse-phase suspension dispersion with water glass according to claim 1, characterized in that: The dispersion speed in step S3 is 100-5000 r / min, and the dispersion time is 1-60 min. 7.The method for preparing micron-sized silica microspheres by reverse-phase suspension dispersion with water glass according to claim 1, characterized in that: The drying temperature in step S4 is 20-200 ℃, and the drying time is 20 min-72 h. 8.The method for preparing micron-sized silica microspheres by reverse-phase suspension dispersion with water glass according to claim 1, characterized in that: The monodisperse micron-sized amorphous silica microspheres have a particle size of 1-500 µm, a specific surface area of 5-800 m 2 / g, and a pore volume of 0.17-0.43 cm 3 / g. 9.The method for preparing micron-sized silica microspheres by reverse-phase suspension dispersion with water glass according to claim 1, characterized in that: The method for preparing the micron-sized silica microspheres does not need to use an emulsifier, and can realize recycling of the organic phase; after 30-50 times of recycling, the prepared monodisperse micron-sized amorphous silica microspheres have a particle size of 1-500 μm, a specific surface area of 5-800 m 2 / g, and a pore volume of 0.17-0.43 cm 3 / g.

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