阅读说明：本技术 二氧化硅空心球及其制备方法和其应用 (Hollow silica sphere and preparation method and application thereof ) 是由 曹宇 韩晖 尹陈麟 吴盖 高昆 于 2020-08-31 设计创作，主要内容包括：本发明涉及材料化学技术领域,具体涉及一种二氧化硅空心球及其制备方法和其应用；所述方法包括下述步骤,将石英砂熔融成石英熔体,向石英熔体中喷吹碳粉,收集粉体,即得；本发明提供一种物理法制备二氧化硅空心球的技术方案,以石英砂作为原料,熔融成液体后用压缩气体喷吹的方式制备得到产物,相比化学法而言,产量更大,工艺更简单,成本更低廉,可生产微米级和不同密度的二氧化硅空心球。(The invention relates to the technical field of material chemistry, in particular to a silicon dioxide hollow sphere, a preparation method and application thereof; fusing quartz sand into a quartz melt, blowing carbon powder into the quartz melt, and collecting powder to obtain the quartz powder; the invention provides a technical scheme for preparing a silicon dioxide hollow sphere by a physical method, which is characterized in that quartz sand is used as a raw material, the quartz sand is melted into liquid, and then the liquid is blown by compressed gas to prepare a product.)

1. A preparation method of a silicon dioxide hollow sphere is characterized by comprising the following steps: the method comprises the following steps of melting quartz sand into a quartz melt, blowing carbon powder into the quartz melt, and collecting powder.

2. The preparation method of the silica hollow sphere according to claim 1, wherein the preparation method comprises the following steps: the quartz sand comprises the following chemical components in percentage by mass: SiO 2₂≥99.8％，Al₂O₃≤0.05％，Fe₂O₃≤0.005％。

3. The preparation method of the silica hollow sphere according to claim 1, wherein the preparation method comprises the following steps: the melting temperature is 1850-2200 ℃.

4. The preparation method of the silica hollow sphere according to claim 1, wherein the preparation method comprises the following steps: the carbon powder is fed into the quartz melt through compressed gas, the pressure of the compressed gas is 1.0-1.6MPa, and the flow of the compressed gas is 10-30m³/min。

5. The preparation method of the silica hollow sphere according to claim 1, wherein the preparation method comprises the following steps: the granularity of the carbon powder is 5-20 microns.

6. The preparation method of the silica hollow sphere according to claim 1, wherein the preparation method comprises the following steps: after the powder is collected, products with different densities are obtained through flotation, cleaning and drying treatment.

7. The preparation method of the silica hollow sphere according to claim 6, wherein the preparation method comprises the following steps: the drying is carried out under the condition of stirring, the drying temperature is 150-200 ℃, and the stirring speed is 5-10 r/min.

8. The preparation method of the silica hollow sphere according to claim 6, wherein the preparation method comprises the following steps: the product obtained by flotation is cleaned by deionized water, and the conductivity is less than 5 mu s/cm.

9. A hollow silica sphere made according to the method of any one of claims 1 to 8, wherein: the granularity of the silicon dioxide hollow sphere is 2-100 microns.

10. A hollow silica sphere made according to any one of claims 1 to 8 or according to claim 9, wherein: is used for preparing special materials or special coatings.

Technical Field

The invention relates to the technical field of material chemistry, in particular to a silicon dioxide hollow sphere, a preparation method and application thereof.

Background

The silica hollow sphere refers to a silica particle having a cavity structure. Based on the characteristics of a hollow structure, the silicon dioxide hollow sphere has the characteristics of small apparent density, high mechanical strength, good dielectric property, low heat conductivity coefficient, good flow property, stable chemical property and the like. The micron-sized silicon dioxide hollow spheres mainly refer to silicon dioxide hollow spheres with the median particle size of 1-200 microns, have the advantages of good dispersity and difficult agglomeration compared with nano-sized silicon dioxide hollow spheres, have wide application prospects in the aspects of electronic materials, biological medicines and the like, and have important industrial value in developing the research of industrial preparation methods.

Disclosure of Invention

The invention aims to provide a preparation method of a silica hollow sphere capable of realizing industrial mass production, which comprises the following steps of melting quartz sand into a quartz melt, blowing carbon powder into the quartz melt, and collecting powder.

In a preferred technical scheme of the invention, the quartz sand comprises the following chemical components in parts by mass: SiO 2₂≥99.8％，Al₂O₃≤0.05％，Fe₂O₃≤0.005％。

In the preferred technical scheme of the invention, Na in the water extraction liquid of the quartz sand⁺≤5.0mg/L，Cl^-≤5.0mg/L。

The method for obtaining the water extract of the quartz sand comprises the following steps: 10g of quartz sand is taken and added into 100mL of pure water, the mixture is stirred for 5 minutes and then is kept stand, and supernatant fluid is taken, namely the water extract of the quartz sand.

In the preferable technical scheme of the invention, the granularity of the quartz sand is 16-120 meshes.

In order to ensure the flow property and the stability of the physicochemical property of the melt, in the preferred technical scheme of the invention, the melting temperature is 1850-2200 ℃.

In a preferred embodiment of the invention, the melting process is carried out in an electric arc furnace. The quartz sand is preferably fused into a quartz melt using a three-phase ac arc furnace or a dc arc furnace.

In the preferred technical scheme of the invention, the blowing process is carried out in a blowing furnace, and the quartz melt enters the blowing furnace through an overflow pipe. Preferably, in order to avoid erosion of high-temperature quartz melt to equipment, the overflow pipe is made of yttrium-stabilized zirconia, and simultaneously, in order to ensure the heat preservation effect and avoid blockage caused by solidification of the melt in the tank, the heat preservation material of the outer pipe of the overflow pipe is mullite brick and rock wool, and the density of the mullite is 0.5-1.0g/m³Rock wool density 0.1g/m³And the heat conductivity coefficient is 0.1W/m.k.

In the preferred technical scheme of the invention, the carbon powder is fed into the quartz melt through compressed gas, the pressure of the compressed gas is 1.0-1.6MPa, and the flow of the compressed gas is 10-30m³/min。

In a preferred technical scheme of the invention, the compressed gas is compressed air, compressed nitrogen, compressed oxygen or compressed carbon dioxide, and is preferably compressed air.

In order to ensure the uniform dispersion effect of the carbon powder, in the preferred technical scheme of the invention, the adding amount of the carbon powder is 5-50 kg/h.

In the preferred technical scheme of the invention, the granularity of the carbon powder is 5-20 microns.

In the preferred technical scheme of the invention, a cyclone separator and/or a bag-type dust collector are/is adopted to collect the powder.

In the preferred technical scheme of the invention, after the powder is collected, products with different densities are obtained through flotation, cleaning and drying treatment.

In a preferred technical scheme of the invention, the flotation method comprises the following steps:

1) putting the collected powder into pure water, collecting suspended solid to obtain product with density less than 1g/cm³；

And/or, 2) putting the solid precipitated in the step 1) into a bleaching liquid A, and collecting suspended solid to obtain a product of which the concentration is 1.0g/cm³Less than or equal to density less than 1.5g/cm³；

And/or, 3) putting the solid precipitated in the step 2) into a flotation liquid B, and collecting suspended solid to obtain a product of which the concentration is 1.5g/cm³Less than or equal to density less than 2.0g/cm³。

In the preferable technical scheme of the invention, the bleaching liquid A is 1.5g/ml zinc chloride solution, and the bleaching liquid B is 2.0g/ml zinc chloride solution.

In a preferred technical scheme of the invention, the cleaning process is as follows: and washing the product obtained by flotation with deionized water, wherein the conductivity of the product is less than 5 mu s/cm after washing.

In the preferable technical scheme of the invention, the drying process comprises dehydration and heating, and the dehydration process adopts any one or combination of filter pressing, filtration, centrifugation and membrane treatment. Preferably, a plate-and-frame filter press is used for dehydration treatment.

In a preferred embodiment of the present invention, the drying is selected from any one of vacuum drying, reduced pressure drying, atmospheric drying, spray drying, and boiling drying, or a combination thereof. Drying is preferably carried out using a rotary kiln.

In the preferred technical scheme of the invention, the drying temperature is 150-200 ℃.

In the preferred technical scheme of the invention, the drying process is carried out under the condition of stirring, and the preferred stirring speed is 5-10 r/min.

The invention also aims to provide the silicon dioxide hollow sphere prepared by the method.

In the preferred technical scheme of the invention, the granularity of the silicon dioxide hollow sphere is 2-100 microns.

The invention also aims to provide application of the hollow silica sphere in preparation of special materials or special coatings.

The invention further aims to provide a system for producing the silicon dioxide hollow spheres, which comprises an electric arc furnace and a blowing furnace, wherein the side wall and the bottom of the electric arc furnace are respectively provided with a feeding port and a slag discharging port, the top and the bottom of the blowing furnace are respectively provided with a feeding port and a slag outlet, the side wall of the blowing furnace adjacent to the feeding port is provided with a gas inlet, the side wall of the blowing furnace far away from the gas inlet is provided with a powder outlet, and the lower end of the electric arc furnace is provided with an overflow pipe leading to the feeding port of the blowing furnace.

In the preferred technical scheme of the invention, the device also comprises a material processor arranged in the blowing furnace, a discharge hole at the bottom of the hopper connected with the feed inlet and a gas outlet at one side of a gas inlet pipe connected with the gas inlet are both communicated with the contraction section of the Venturi tube through a feed pipe, and the tail end of the diffusion section of the Venturi tube is connected with a nozzle.

In the preferred technical scheme of the invention, a carbon powder inlet is arranged on a pipeline which extends from the outside to be communicated with the gas inlet.

In the preferred technical scheme of the invention, the cavity of the nozzle is integrally in a cone shape with a large left and a small right, and the peripheral wall of the nozzle is uniformly provided with blowing holes.

In the preferred technical scheme of the invention, the material processor is horizontally arranged in the blowing furnace along the length direction of the venturi tube.

In the preferred technical scheme, the invention also comprises a cyclone collector, wherein a powder outlet of the blowing furnace is communicated with an air inlet port of the cyclone collector through a pipeline, and the bottom of the cyclone collector is also provided with a discharge port.

In the preferred technical scheme, the cyclone collector further comprises a cloth bag collector, wherein an air inlet and an air outlet of the cloth bag collector are respectively connected with an air outlet port at the bottom of the cyclone collector and an air suction port of the fan, and a discharge port is further arranged at the bottom of the cloth bag collector.

In the preferred technical scheme of the invention, the outer part of the overflow pipe is wrapped with the heat insulation layer.

The density, wall thickness and chemical composition of the hollow silica spheres were measured according to the following methods, unless otherwise specified.

1. The density detection method of the silicon dioxide hollow sphere comprises the following steps: and (4) detecting according to GB/T4472-2011 for measuring the density and the relative density of chemical products.

2. The wall thickness detection method of the silicon dioxide hollow sphere comprises the following steps:

(1) placing a proper amount of silicon dioxide hollow sphere powder in an agate mortar, and grinding for 5 minutes;

(2) collecting a scanning electron microscope photo of the grinding powder;

(3) the thickness of the hollow sphere fragments was marked with a scanning electron microscope.

3. The method for detecting the chemical components of the silicon dioxide hollow sphere comprises the following steps: detection was carried out according to SJT10675-2002 Fine silica powder for electronics and Electrical appliances industries.

Unless otherwise indicated, when the present invention relates to percentages between liquids, said percentages are volume/volume percentages; the invention relates to the percentage between liquid and solid, said percentage being volume/weight percentage; the invention relates to the percentages between solid and liquid, said percentages being weight/volume percentages; the balance being weight/weight percent.

Compared with the prior art, the invention has the following beneficial technical effects: the invention provides a technical scheme for preparing a silicon dioxide hollow sphere by a physical method, which is characterized in that quartz sand is used as a raw material, the quartz sand is melted into liquid, and then the liquid is blown by compressed gas to prepare a product.

Drawings

FIG. 1 is a schematic structural view of the present invention;

fig. 2 is a schematic diagram of the structure 30 (material handler) of fig. 1.

Detailed Description

The present invention will be described below with reference to examples, but the present invention is not limited to the examples.

Description of the raw materials:

1. quartz sand, commercially available, having a particle size of 16-40 mesh, was tested to have chemical composition: SiO 2₂99.85% of Fe₂O₃0.0025% of Al₂O₃0.02% of Na in the water extract⁺Content 2.2mg/L, Cl^-The content is 1.5 mg/L.

2. Other materials and equipment are commercially available.