TW201914687A - Method for preparing high-purity micron-sized spherical silicon dioxide micropowder capable of producing a silicon oxide microsphere with extremely high purity by a simple operation - Google Patents

Abstract

The present invention discloses a method for preparing a high-purity micron-sized spherical silicon dioxide micropowder, which includes the following steps: (1) providing a silicon-containing precursor solution; (2) adding the silicon-containing precursor solution to the emulsifier-containing oil phase and stirring it to obtain a mixed solution; and (3) adding a basic catalyst to the mixed solution, standing and aging for a while, washing the precipitate with a mixture of solvent and water, and obtaining the silicon oxide microsphere after drying; wherein the silicon-containing precursor solution is one or a mixture of two or more of Si(OR)4, ethyl silicate 40, ethyl silicate 32, and SiR2(OR1)3, in which R, R1, and R2 are independent C1-3 alkyl groups. The silicon oxide microsphere of the present invention has extremely high purity, and the content of all metal impurities is 0.2 ppm or less. In addition, the preparation method of the present invention is simple in operation, and the product in the preparation process is easy to handle, and the obtained silicon oxide microsphere have a particle diameter of 0.3[mu]m to 40[mu]m.

Description

 Preparation method of high-purity micron-sized spherical cerium oxide micropowder  

The invention relates to a preparation method of high-purity micro-scale spherical cerium oxide micropowder.

The high-purity ceria microspheres have low radioactive element content and micron-sized spheroidization, which can reduce the expansion coefficient, enhance the mechanical and electrical properties of the material, improve the flame retardant performance, and at the same time reduce the water absorption rate of the molding compound. At present, it has been widely used in aviation, aerospace, electronic information, new coatings, special ceramics, high-grade cosmetics, high-efficiency catalysts, liquid chromatography fillers, pigments, large-screen liquid crystal displays, and ultra-large integrated circuit molding materials.

At present, the most successful research on the spheroidization of cerium oxide powder is Japan and the United States. The high-purity micron-sized raw materials are water glass, purified quartz, n-decanoic acid ethyl ester, and antimony tetrachloride. The preparation method includes a physical method and a chemical synthesis method of a ruthenium compound, wherein the physical method includes an ultrafine pulverization mechanical method, a high frequency plasma melting method, a combustion method (a gas flame method, a high temperature melt blast method) (see CN102815713B, CN102530962B, CN101023038B), and represents The company has Japan TATSTMORL, Japan Electrochemistry, Sturtevant.mill in the United States; 矽 compound chemical synthesis methods include seed method, precipitation method, sol-gel (Sol-Gel), chemical liquid method, emulsification method, etc. Sukgyung At.

The microspheres prepared by the plasma method have a dense structure and high bulk density, but the energy consumption is high, the temperature field is small and concentrated, the temperature range is difficult to control, and it is difficult to enlarge, and it is difficult to form a large-scale production, which is mainly used in research fields. The gas flame method is demanding and the technical parameters are difficult to control. At present, Japan has energy production equipment, but Japan restricts the export of key technologies and equipment of the process. Heating devices for high temperature melt gas jet injection require a stable temperature field, an easily adjustable temperature range, and a clean heat source environment that does not cause secondary contamination of the fine powder. The combustion method is the most difficult to solve the problem of sample contamination. Gas phase thermal decomposition (CN102001670B) primary particles 7~20nm, the production process is easy to automate control, equipment investment is large, the production scale should not be too large, and the product price is expensive.

The microspheres prepared by the seed method (CN101205067B) have a small particle size and are not suitable for amplification. The chemical precipitation method is to prepare a precursor precipitate by adding a different chemical component in a solution state, adding a suitable precipitant to the mixture, and then drying or calcining the precipitate to obtain a powder. The chemical liquid phase method (CN104724716A, CN104176739A) easily controls the shape and particle size, and the industrial production cost is low, but the volume shrinkage is large. Sol-gel method is to add acid or acid anhydride to the solution of lanthanum source, reduce the pH value of the system, gelatinize the ruthenate, and then filter and dry the ruthenium gel to remove the organic components, thus obtaining SiO. ₂ powder, gel drying time is long, containing some organic impurities. CN104556076B discloses that the oil-in-water emulsification method (O/W) has a long curing time, affecting industrialization and productivity, and the water-in-oil emulsification method (W/O) disclosed by CN104030302B uses a large amount of flammable and explosive organic solvent (for example, diesel). As a reaction medium, it has certain harm to the human body and the environment. Mixing with sodium citrate solution, adding acid (H ₂ SO ₄ , HCl, etc.) to precipitate reaction, filtering, drying, pulverizing and simmering SiO ₂ powder, the precipitation formation rate is faster, but the reaction is not easy to control, and the metal content is easily exceeded.

Therefore, there is still a need in the art to develop a new process simple preparation method, which can prepare microspheres of different particle sizes and avoid the disadvantages such as agglomeration between the microspheres.

The object of the present invention is to provide a method for preparing a high-purity micron-sized spherical ceria micropowder. The method comprises the principle of chemically synthesizing barium micropowder by water-in-oil (W/O) emulsification method, and the purity thereof is extremely high, and the safe and non-toxic white oil is adopted. The organic solvent used in place of the conventional one is a reaction medium, the curing time is fast, the spheroidization rate is high, the metal ion concentration is close to zero, that is, the content of all metal impurities is 0.2 ppm or less, and the preparation method of the invention is simple in operation and in the preparation process. The product is easy to handle, and the final product cerium oxide microspheres have a particle size of 0.3 μm to 40 μm.

In a first aspect of the present invention, there is provided a method for preparing a cerium oxide microsphere, the preparation comprising the steps of: i) providing a cerium-containing precursor solution; ii) adding the cerium-containing precursor solution to an emulsifier-containing solution The oil phase is stirred to obtain a mixed solution; iii) a basic catalyst is added to the mixed solution, and after standing and aging, the precipitate is washed with a mixture of a solvent and water, and dried to obtain the cerium oxide microspheres, wherein The cerium-containing precursor is one or a mixture of two or more of Si(OR) ₄ , ethyl decanoate 40 , ethyl decanoate 32 , and SiR ₂ (OR ₁ ) ₃ , wherein R, R ₁ , and R ₂ Each is independently a C _1-3 alkyl group.

In another preferred embodiment, the ruthenium-containing precursor is one or a mixture of two or more of tetramethyl phthalate, tetraethyl phthalate, methyltrimethoxydecane, and ethyltrimethoxydecane.

In another preferred embodiment, the solvent of the ruthenium-containing precursor solution is water, the pH of the solution is 1-4, and the mass ratio of the ruthenium-containing precursor to water is 0.3:1 to 3:1.

In another preferred embodiment, the cerium-containing precursor solution further comprises SiO ₂ .

In another preferred embodiment, the cerium-containing precursor solution is a tetraethyl phthalate solution, wherein the SiO ₂ content is 5 parts by weight to 35 parts by weight based on 100 parts by weight of the total weight of the tetraethyl phthalate solution. Share.

In another preferred embodiment, the emulsifier is a nonionic emulsifier.

In another preferred embodiment, the oil phase is an alkane liquid, and the kinematic viscosity of the alkane liquid is 5 mm ² /s. Kinematic viscosity (40 ° C) 32mm ² / s.

In another preferred embodiment, the alkane liquid is a white oil.

In another preferred embodiment, the basic catalyst is one or a combination of two or more of ammonia water, diethylamine, and triethylamine.

In another preferred embodiment, the solvent is one or a mixture of two or more of ethyl acetate, ethanol, isopropanol, propanol, and butanol.

According to a second aspect of the present invention, a cerium oxide microsphere is prepared, which is prepared by the preparation method of the first aspect, and the obtained cerium oxide microsphere has an average particle diameter of 0.3 μm to 40 μm. .

The ceria microspheres of the present invention are extremely pure, and all metal impurities are contained in an amount of 0.2 ppm or less.

The invention is advantageous in that:

(1) Using a cerium-containing precursor with a low alkali metal content as a raw material, replacing the diesel with a safe and non-toxic white oil as a reaction medium, and regulating the kinematic viscosity of the oil phase, the curing time is fast, the spheroidization rate is high, and the metal ion The free anion meets the requirements of high purity, the particle size is controllable, and the operation is simple.

(2) The prepared microspheres can reduce the thermal expansion coefficient, water absorption rate, internal stress, shrinkage rate and thermal conductivity of the molding compound; improve the strength, wear resistance, anti-aging property and surface smoothness of the material; improve the elasticity , wear resistance and aging resistance.

It is to be understood that within the scope of the present invention, the various technical features of the present invention and the technical features specifically described in the following (as in the embodiments) may be combined with each other to constitute a new or preferred technical solution. Due to space limitations, we will not repeat them here.

1 is a SEM picture of a 3 μm monodisperse ceria microsphere prepared in Example 1.

2 is a SEM picture of a 8 μm monodisperse ceria fine powder prepared in Example 2.

Figure 3 is a SEM picture of a 10 μm monodisperse ceria fine powder prepared in Example 3.

4 is a SEM picture of a 15 μm monodisperse ceria fine powder prepared in Example 4.

5 is a SEM picture of a 20 μm monodisperse ceria fine powder prepared in Example 5.

Figure 6 is a SEM picture of a 35 μm monodisperse ceria fine powder prepared in Example 6.

Figure 7 is a SEM picture of a 5 μm monodisperse ceria fine powder prepared in Example 7.

Figure 8 is a SEM picture of a 0.5 μm monodisperse ceria fine powder prepared in Example 7.

The inventors of the present application have extensively and intensively studied to develop a method for preparing high-purity micron-sized spherical cerium oxide micropowder for the first time, and the ruthenium dioxide microsphere prepared by the emulsification method of the high-purity yttrium-containing precursor is simple in process. The method has the advantages of high purity and good heat resistance, and microspheres with different particle diameters can be prepared by the method, and the disadvantages such as agglomeration between the microspheres are avoided. On the basis of this, the present invention has been completed.

Preparation

The invention provides a method for preparing cerium oxide microspheres, comprising the steps of: i) providing a cerium-containing precursor solution; ii) adding the cerium-containing precursor solution to an oil phase containing an emulsifier and stirring to obtain a mixture Solution; iii) A basic catalyst is added to the mixed solution, and after standing and aging, the precipitate is washed with a mixture of a solvent and water, and dried to obtain the cerium oxide microsphere.

Step i) The cerium-containing precursor is one or a mixture of two or more of Si(OR) ₄ , ethyl decanoate 40 , ethyl decanoate 32 and SiR ₂ (OR ₁ ) ₃ , wherein R, R ₁ And R ₂ are each independently a C _1-3 alkyl group; preferably Tetramethyl orthosilicate (TMOS), tetraethyl orthosilicate (TEOS), methyltrimethoxysilane or methyltrimethoxysilane or One or a mixture of two or more of Ethyltrimethoxysilane, more preferably tetraethyl phthalate (TEOS).

Step i) The cerium-containing precursor solution comprises a solvent, wherein the solvent is water, the pH of the solution is 1-4, and the mass ratio of the cerium-containing precursor to water is 0.3:1 to 3:1.

Step i) The cerium-containing precursor solution further comprises a SiO ₂ , wherein the SiO ₂ content is from 5 parts by weight to 35 parts by weight, preferably 15 parts by weight, based on 100 parts by weight of the total weight of the cerium-containing precursor 30 parts by weight. In some embodiments, the cerium-containing precursor is tetraethyl citrate and the SiO ₂ content is from 5 parts by weight to 35 parts by weight.

Step ii) The emulsifier is a nonionic emulsifier, the nonionic emulsifier is OP series (alkyl phenol and ethylene oxide condensate), NP series (alkyl phenol and ethylene oxide condensate) At least one or more of the Span series (Span, sorbitan fatty acid ester), Tween series (Tween, polyoxyethylene sorbitan fatty acid ester). Preferably, it is a composite emulsifier formed by the Span series and the Tween series, wherein the Span series accounts for 70-90% of the composite emulsifier, and the Tween series accounts for 10-30% of the composite emulsifier. Considering the stability of the composite emulsifier, a composite emulsifier formed by Span-80 and Tween-80 is more preferred.

Step ii) The HLB value (Hydrophile-Lipophile Balance Number, also referred to as water-oiliness) of the emulsifier is 4.5 to 5.6.

Step ii) The oil phase is an alkane liquid, wherein the alkane liquid is white oil, at least one or more of solvent gasoline, and white oil is preferred in view of process safety and environmental protection.

Step ii) The kinematic viscosity of the oil phase: 5 mm ² /s Kinematic viscosity (40 ° C) 32mm ² / s. If the viscosity is less than 5 mm ² /s, it is difficult to obtain a microsphere having a large particle size, and the viscosity is more than 32 mm ² /s, which is not easy to be post-treated.

Step ii) The stirring time is 10 min to 2 h, including the time of pre-emulsification and emulsification, and the stirring temperature is 20 ° C to 60 ° C.

Step iii) is to add a basic catalyst to the mixed solution by one-time addition or continuous dropwise addition, and after standing and aging, the supernatant liquid and the lower white precipitate are produced, and then the mixture is washed with a mixture of solvent and water. The precipitate is white and dried to obtain the cerium oxide microspheres, wherein the solvent is one or a mixture of two or more of ethyl acetate, ethanol, isopropanol, propanol and butanol, and dried at 105 ° C. 05hr~3hr, then 05~1hr at 400°C~800°C.

Step iii) The basic catalyst is one or a combination of two or more of ammonia water, diethylamine, and triethylamine.

Step iii) The alkaline catalyst is added to the mixed solution for a reaction time of 1 h to 10 h, including the time of standing aging, and the stirring temperature is 20 ° C to 80 ° C.

The preparation method of the high-purity micron-sized ceria microspheres provided by the present invention, in addition to the above steps i) to iii), may further comprise the step iv): iv) taking the step iii) after standing and aging, the obtained supernatant liquid Purification and drying are carried out by separating the reactants by centrifugation and washing with a mixture of a solvent and water.

Step iv) The solvent is one or a mixture of two or more of ethyl acetate, ethanol, isopropanol, propanol and butanol.

In another aspect of the present invention, a ceria microsphere is prepared, which is prepared by the preparation method of the above step i) to the step iii) or the step i) to the step iv). The average particle size of the cerium oxide microspheres is from 0.3 μm to 40 μm.

The microsphere prepared by the method of the invention has the characteristics of low halogen content and low metal content, high purity and good heat resistance, and microspheres with different particle diameters can be prepared by the method, and agglomeration between the microspheres is avoided. Disadvantages, can be used in electronic packaging materials (EMC filler), resin-based composite materials, rubber and plastics industrial polymers, can be used in biotechnology for chemical, pharmaceutical, military (additional toner, PET film filler), Can be used as a highly efficient catalyst, food, cosmetics (quartz).

The above-mentioned features mentioned in the present invention, or the features mentioned in the embodiments, may be arbitrarily combined. All of the features disclosed in the present specification can be used in combination with any of the compositions, and the various features disclosed in the specification can be replaced by any alternative feature that provides the same, equal or similar purpose. Therefore, unless otherwise stated, the disclosed features are only general examples of equal or similar features.

The invention is further illustrated below in conjunction with specific embodiments. It is to be understood that the examples are not intended to limit the scope of the invention. The experimental methods in the following examples which do not specify the specific conditions are usually carried out according to conventional conditions or according to the conditions recommended by the manufacturer. Unless otherwise stated, percentages and parts are by weight and parts by weight.

Unless otherwise defined, all professional and scientific terms used herein have the same meaning as those skilled in the art. In addition, any methods and materials similar or equivalent to those described may be employed in the methods of the invention. The preferred embodiments and materials herein are for illustrative purposes only.

 Example 1:  

Ethyl ruthenate (TEOS) and ethyl acetate were distilled off under reduced pressure.

Step i) taking 200g of deionized water, adding acid to pH=1.50, mixing with 90g of ethyl ortho-nonanoate (TEOS), reacting for 0.5h, forming a clear and transparent cerium-containing precursor solution, wherein 100 parts by weight The SiO ₂ content is 15 parts by weight based on the total weight of the ruthenium precursor; step ii) takes 2.63 g Sipan-80, 0.36 g Tween-80, 85 g kinematic viscosity (40 ° C) = 5 mm ² /s white oil, rotation speed 200 rpm, time 15 min; 40 g of cerium sol was added to the mixed white oil at a speed of 20000 rpm for 15 min to obtain a white emulsion; Step iii) Ammonia water was added for 2 h, and after standing for 2 h, a white precipitate was taken; After multiple washings, high-purity micron-sized spherical ceria microspheres 1 can be obtained after drying.

The SEM image of the obtained high-purity micron-sized spherical ceria microspheres is shown in Fig. 1.

 Example 2:  

Ethyl ruthenate (TEOS) and ethyl acetate were distilled off under reduced pressure.

Step i) taking 90g of deionized water, adding acid to pH=2.5, mixing with 180g of ethyl ortho-decanoate (TEOS), reacting for 1.5h, forming a clear and transparent cerium-containing precursor solution, wherein, in 100 parts by weight The SiO ₂ content is 30 parts by weight based on the total weight of the ruthenium precursor; step ii) 8.76 g Sipan-80, 1.24 g Tween-80, 85 g kinematic viscosity (40 ° C) = 10 mm ² /s oil phase, rotation speed 200 rpm, time 25 min; 85 g of cerium sol was added to the mixed white oil at 10,000 rpm for 10 min to obtain a white emulsion; step iii) diethylamine was added for 2 h, and after standing for 2 h, a white precipitate was taken; The ethyl ester is washed several times, and after drying, high-purity micron-sized spherical ceria microspheres 2 can be obtained.

The SEM image of the obtained high-purity micron-sized spherical ceria microspheres is shown in Fig. 2.

 Example 3:  

Ethyl ruthenate (TEOS) and ethyl acetate were distilled off under reduced pressure.

Step i) taking 90g of deionized water, adding acid to pH=2.5, mixing with 180g of ethyl ortho-decanoate (TEOS), reacting for 1.5h, forming a clear and transparent cerium-containing precursor solution, wherein, in 100 parts by weight The SiO ₂ content is 30 parts by weight based on the total weight of the ruthenium precursor; step ii) 8.76 g Sipan-80, 1.24 g Tween-80, 85 g kinematic viscosity (40 ° C) = 15 mm ² /s white oil, rotation speed 200 rpm, time 30 min; 85 g of cerium sol was added to the mixed white oil at 10,000 rpm for 10 min to obtain a white emulsion; step iii) triethylamine was added for 2 h, and after standing for 3 h, a white precipitate was taken; The ethyl ester is washed several times, and after drying, high-purity micron-sized spherical cerium oxide microspheres 3 can be obtained.

The SEM image of the obtained high-purity micron-sized spherical ceria microspheres is shown in FIG.

 Example 4:  

Ethyl ruthenate (TEOS) and ethyl acetate were distilled off under reduced pressure.

Step i) taking 90g of deionized water, adding acid to pH=2.5, mixing with 180g of ethyl ortho-decanoate (TEOS), reacting for 1.5h, forming a clear and transparent cerium-containing precursor solution, wherein, in 100 parts by weight The SiO ₂ content is 30 parts by weight based on the total weight of the ruthenium precursor; step ii) 8.76 g Sipan-80, 1.24 g Tween-80, 100 g kinematic viscosity (40 ° C) = 26 mm ² /s white oil, rotation speed 200 rpm, time 40 min; 85 g of cerium sol was added to the mixed oil phase at 10,000 rpm for 10 min to obtain a white emulsion; Step iii) Ammonia water was added for 3 h, and after standing for 3 h, a white precipitate was taken; After multiple washings, high purity micron-sized spherical ceria microspheres 4 can be obtained.

The SEM image of the obtained high-purity micron-sized spherical ceria microspheres is shown in Fig. 4.

 Example 5:  

Ethyl ruthenate (TEOS) and ethyl acetate were distilled off under reduced pressure.

Step i) taking 90g of deionized water, adding acid to pH=2.5, mixing with 180g of ethyl ortho-decanoate (TEOS), reacting for 1.5h, forming a clear and transparent cerium-containing precursor solution, wherein, in 100 parts by weight The SiO ₂ content is 30 parts by weight based on the total weight of the ruthenium precursor; step ii) 8.76 g Sipan-80, 1.24 g Tween-80, 120 g kinematic viscosity (40 ° C) = 26 mm ² /s oil phase, rotation speed At 200 rpm and 40 min, 85 g of cerium sol was added to the mixed oil phase at a speed of 8000 rpm for 10 min to obtain a white emulsion. Step iii) ammonia water was added for 3 h, and after standing for 3 h, a white precipitate was taken; After washing, the high-purity micron-sized spherical ceria microspheres 5 can be obtained after drying, and the SEM image of the obtained high-purity micron-sized spherical ceria microspheres is shown in FIG. 5.

 Example 6  

Ethyl ruthenate (TEOS) and ethyl acetate were distilled off under reduced pressure.

Step i) taking 90g of deionized water, adding acid to pH=2.5, mixing with 180g of ethyl ortho-decanoate (TEOS), reacting for 1.5h, forming a clear and transparent cerium-containing precursor solution, wherein, in 100 parts by weight The SiO ₂ content is 30 parts by weight based on the total weight of the ruthenium precursor; step ii) 8.76 g Sipan-80, 1.24 g Tween-80, 160 g kinematic viscosity (40 ° C) = 32 mm ² /s oil phase, rotation speed 200 rpm, time 50 min; 85 g of cerium sol was added to the mixed oil phase at 8000 rpm for 10 min to obtain a white emulsion; step iii) ammonia water was added for 4 h, and after standing for 4 h, a white precipitate was taken; After multiple washings and drying, high-purity micron-sized spherical ceria microspheres 6 are obtained, and the SEM image of the obtained high-purity micron-sized spherical ceria microspheres is shown in FIG. 6.

 Example 7  

Ethyl ruthenate (TEOS) and ethyl acetate were distilled off under reduced pressure.

Step i) taking 90g of deionized water, adding acid to pH=2.5, mixing with 90g of ethyl ortho-nonanoate (TEOS), reacting for 1.5h, forming a clear and transparent cerium-containing precursor solution, wherein, in 100 parts by weight The SiO ₂ content is 23 parts by weight based on the total weight of the ruthenium precursor; step ii) takes 4.38 g Span-80, 0.62 g Tween-80, 85 g kinematic viscosity (40 ° C) = 32 mm ² /s white oil, rotation speed 200 rpm, time 50 min; 85 g of cerium sol was added to the mixed white oil at 10,000 rpm for 10 min to obtain a white emulsion; step iii) ammonia water was added for 2 h, and after standing for 4 h, a white precipitate was taken; After repeated washing, after drying, high-purity micron-sized spherical ceria microspheres 7 can be obtained, and the obtained SEM image of the high-purity micron-sized spherical ceria microspheres is as shown in Fig. 7, step iv) and step iii) After standing and aging, the solid obtained by centrifugation of the supernatant liquid is washed several times with water and ethyl acetate, and dried to obtain high-purity micron-sized spherical cerium oxide microspheres 8.

The SEM image of the obtained high-purity micron-sized spherical ceria microspheres is shown in Fig. 8.

 Comparative Example 1:  

Ethyl ruthenate (TEOS) and ethyl acetate were distilled off under reduced pressure.

Step i) taking 90g of deionized water, adding acid to pH=2.5, mixing with 90g of ethyl ortho-nonanoate (TEOS), reacting for 1.5h, forming a clear and transparent cerium-containing precursor solution, wherein, in 100 parts by weight The SiO ₂ content is 23 parts by weight based on the total weight of the ruthenium precursor; step ii) takes 4.38 g Span-80, 0.62 g Tween-80, 85 g kinematic viscosity (40 ° C) = 3 mm ² /s white oil, rotation speed 200 rpm, time 50 min; 85 g of cerium sol was added to the mixed white oil at 10,000 rpm for 10 min to obtain a white emulsion; step iii) ammonia water was added for 2 h, and after standing for 4 h, a white precipitate was taken; After multiple washings, high purity micron-sized spherical ceria microspheres 9 can be obtained after drying.

 Comparative Example 2:  

Ethyl ruthenate (TEOS) and ethyl acetate were distilled off under reduced pressure.

Step i) taking 90g of deionized water, adding acid to pH=2.5, mixing with 90g of ethyl ortho-nonanoate (TEOS), reacting for 1.5h, forming a clear and transparent cerium-containing precursor solution, wherein, in 100 parts by weight The SiO ₂ content is 23 parts by weight based on the total weight of the ruthenium precursor; step ii) takes 4.38 g Span-80, 0.62 g Tween-80, 85 g kinematic viscosity (40 ° C) = 55 mm ² /s white oil, rotation speed 200 rpm, time 50 min; 85 g of cerium sol was added to the mixed white oil at 10,000 rpm for 10 min to obtain a white emulsion; step iii) ammonia water was added for 2 h, and after standing for 4 h, a white precipitate was taken; After multiple washings, high purity micron-sized spherical ceria microspheres 10 can be obtained.

 Determination of free impurity ion content in spherical cerium dioxide PCT test water extract:  

Weigh 5.500g of sample powder into a 100mL Teflon-lined stainless steel reaction tank, add 50mL of pure water, seal and place in an oven at 120 °C for 20h, remove it, let it cool to room temperature, and take the supernatant. Measured, using the pure water used as the blank, using Agilent, ICP 720 Inductively Coupled Plasma Spectrometer (ICP-AES) to determine the content of free sodium, potassium, calcium and magnesium ions in the extract; using Dionex ICS2000 ion chromatograph The chloride ion content was determined. The test results of the relevant indicators of the extract are shown in Table 2. The data in the table show that the synthesized spherical cerium oxide is extracted by pure water, and the harmful ion content in the extract is less than 0.2 ppm. The powder can be used completely. The supporting materials of the integrated circuit will not corrode the circuit.

According to the above experiment, the cerium oxide microspheres obtained by the invention have a content of all metal impurities of 0.2 ppm or less, and the purity is extremely high, and the preparation method of the invention is simple in operation, and the product in the preparation process is easy to handle, and finally The obtained cerium oxide microspheres have a particle diameter of 0.5 μm to 35 μm.

All documents mentioned in the present application are hereby incorporated by reference in their entirety in their entireties in the the the the the the the the In addition, it is to be understood that various modifications and changes may be made by those skilled in the art in the form of the present invention.

Claims (10)

A method for preparing cerium oxide microspheres, the method comprising the steps of: i) providing a cerium-containing precursor solution; ii) adding the cerium-containing precursor solution to an oil phase containing an emulsifier and stirring Obtaining a mixed solution; iii) adding a basic catalyst to the mixed solution, and after standing and aging, washing the precipitate with a mixture of a solvent and water, and drying to obtain the cerium oxide microsphere, wherein the cerium-containing precursor Is a mixture of one or more of Si(OR) ₄ , ethyl decanoate 40 , ethyl decanoate 32 , and SiR ₂ (OR ₁ ) ₃ , wherein R, R ₁ and R ₂ are each independently C _{1 . -3} alkyl.  The preparation method according to claim 1, wherein the ruthenium-containing precursor is one or more of tetramethyl phthalate, tetraethyl citrate, methyltrimethoxydecane and ethyltrimethoxydecane. mixture.    The preparation method according to claim 1, wherein the solvent of the ruthenium-containing precursor solution is water, the pH of the solution is 1-4, and the mass ratio of the ruthenium-containing precursor to water is 0.3:1 to 3:1.   The preparation method according to claim 1, wherein the cerium-containing precursor solution further comprises SiO ₂ . The preparation method according to claim 4, wherein the cerium-containing precursor solution is a tetraethyl citrate solution, wherein the SiO ₂ content is 5 parts by weight based on 100 parts by weight of the total weight of the tetraethyl phthalate solution. 35 parts by weight.  The preparation method according to claim 1, wherein the emulsifier is a nonionic emulsifier.   The preparation method according to claim 1, wherein the oil phase is an alkane liquid, and the kinematic viscosity of the alkane liquid is 5 mm ² /s. Kinematic viscosity (40 ° C) 32mm ² / s.  The production method according to claim 1, wherein the basic catalyst is one or a combination of two or more of ammonia water, diethylamine, and triethylamine.    The production method according to claim 1, wherein the solvent is one or a mixture of two or more of ethyl acetate, ethanol, isopropanol, propanol and butanol.    A cerium oxide microsphere, wherein the cerium oxide microsphere is produced by the preparation method described in claim 1, and the obtained cerium oxide microsphere has an average particle diameter of 0.3 μm to 40 μm.