CN113336233B

CN113336233B - Preparation method of high-purity nano quartz powder

Info

Publication number: CN113336233B
Application number: CN202110791495.4A
Authority: CN
Inventors: 王先广; 杜高翔; 唐绍文; 黄秋芸; 詹天卫
Original assignee: Beijing Yixing Technology Co ltd; Jiangxi Mineral Resources Guarantee Service Center
Current assignee: Beijing Yixing Technology Co ltd; Jiangxi Mineral Resources Guarantee Service Center
Priority date: 2021-07-13
Filing date: 2021-07-13
Publication date: 2022-05-13
Anticipated expiration: 2041-07-13
Also published as: CN113336233A

Abstract

The invention belongs to the field of inorganic non-metallic materials, and particularly relates to a preparation method of high-purity nano quartz powder. The preparation method takes novel minerals as raw materials, firstly, dispersant is added for the first grinding pretreatment to obtain small molecular particles, and the subsequent separation and impurity removal are facilitated; then adding absolute ethyl alcohol and deionized water to obtain a suspension, accelerating the carbon settling velocity, settling the flocculated carbon at the lower layer of the suspension, and then adding an oxidant for decarburization treatment, thus effectively removing carbon; then, through high-speed centrifugation, collecting suspended silicon dioxide particles, washing with acid liquor, and removing inorganic impurities; finally, nano grinding is carried out again to obtain the high-purity nano quartz powder. The method has the advantages of simple preparation, easy operation, low energy consumption, low cost and uniform granularity, and the prepared high-purity nano quartz powder d₉₀＜100nm，SiO₂The content is more than 99.9 percent, and the method can be widely applied to various fields of biology, medicine, construction, spice, fiber, energy storage and the like.

Description

Preparation method of high-purity nano quartz powder

Technical Field

The invention belongs to the field of inorganic non-metallic materials, and particularly relates to a preparation method of high-purity nano quartz powder.

Background

The quartz is a nonmetallic mineral with abundant reserves, the Mohs hardness is 7, the acid resistance is strong, and the electricity insulation is excellentThe nature is strong. The superfine quartz powder is a high-quality neutral inorganic filler, and is widely used in the industries of plastics, rubber, coatings, electronics, high-tech products and the like, wherein the high-tech industry has quite strict requirements on the purity, the granularity and the granularity distribution of the superfine quartz powder. The application field of the nano quartz powder is very wide, and almost all the original SiO applied is involved₂Powder industries, e.g. using SiO as a primary constituent₂The powder material is used as a product of the filler. While the original process flow is not changed, the nano SiO is used₂As the filler, the product has greatly improved functions and performance indexes.

At present, the method for preparing high-purity quartz powder mainly has two main ways: the first is a physical method, namely a mechanical crushing method; the second is chemical synthesis method, including gas phase synthesis method and liquid phase synthesis method. The mechanical crushing method is that natural crystal is used as raw material, and the process flow is as follows: crystal raw ore → crushing → magnetic separation → flotation → acid leaching → drying → roasting → magnetic separation → finished quartz powder. Although the process for preparing the quartz powder by the mechanical crushing method is simple, impurities are easily brought in, the energy consumption is high, the cost is high, the powder characteristics are difficult to control, the preparation efficiency is low, and the particle size distribution is wide. In addition, the raw material natural crystal belongs to rare mineral products, particularly primary and secondary crystals, which are gradually exhausted, and the reserves of the crystals cannot meet the current demand of high-purity quartz powder. While many countries have long turned their goals to abundant silica minerals, new sources of quartz mineral raw materials are continually being explored. However, because of different mineralizing geological conditions, the purification process technology and equipment are the biggest bottleneck restricting the large-scale exploitation of silica minerals.

Disclosure of Invention

The invention provides a method for preparing high-purity nano quartz powder by taking novel minerals as raw materials based on the composition of the novel minerals. The novel mineral raw material is a novel natural mineral found in some places of Jiangxi province, the appearance of the novel mineral is black, and the main mineral components are silicon dioxide, carbon and trace organic matters. According to the preparation method, the dispersing agent is added for the first grinding pretreatment to obtain small molecular particles, so that the subsequent separation and impurity removal are facilitated; then adding absolute ethyl alcohol and deionized water to obtain a suspension, accelerating the carbon settling velocity, settling the flocculated carbon at the lower layer of the suspension, and then adding an oxidant for decarburization treatment, thus effectively removing carbon; then, through high-speed centrifugation, collecting suspended silicon dioxide particles, and washing with acid liquor, inorganic impurities can be removed; finally, nano grinding is carried out again to obtain the high-purity nano quartz powder.

The method has the advantages of simple preparation, easy operation, low energy consumption, low cost and uniform granularity, and the prepared high-purity nano quartz powder d₉₀＜100nm，SiO₂The content is more than 99.9 percent, and the method can be widely applied to various fields of biology, medicine, construction, spice, fiber, energy storage and the like.

The technical scheme of the invention is as follows: the novel mineral is used as a raw material, a zirconia ceramic ball is adopted for grinding twice, absolute ethyl alcohol is used for layering, an oxidant is used for decarburization, and impurities are removed through acid washing to prepare the novel mineral;

the novel mineral comprises a crystalline component and an amorphous component, wherein the crystalline component accounts for 78.61% of the mass fraction of the mineral, and the amorphous component accounts for 21.39% of the mass fraction of the mineral; the crystalline component comprises quartz, pyrite, kaolinite and mica, wherein the quartz accounts for 91% of the mass fraction of the crystalline component; the amorphous substance comprises water, simple substance carbon and organic matters, wherein the simple substance carbon accounts for 95.1 percent of the mass fraction of the amorphous component;

in a preferred embodiment, the method comprises the following steps:

s1, uniformly mixing the novel mineral with zirconia ceramic balls and deionized water, adding a dispersing agent, grinding in a medium stirring mill until the powder d50 is less than 2 microns and d90 is less than 20 microns, and separating slurry from the grinding balls to obtain dispersed slurry;

s2, adding deionized water into the dispersed slurry, adjusting the solid-to-liquid ratio, adding absolute ethyl alcohol, fully stirring and dispersing, standing for 10-30min, and taking the upper layer slurry;

s3, placing the upper layer slurry into a glass container, and adding an oxidant to react to obtain reaction slurry;

s4, centrifuging the reaction slurry by using a high-speed centrifuge, pouring out clear liquid, and taking out precipitate;

s5, placing the precipitate into a polytetrafluoroethylene container, adding acid liquor to react fully, after the reaction is finished, namely, no air bubbles are generated in the reaction, washing the reaction product with deionized water until the pH value is more than 6, and obtaining a filter cake;

s6, adding deionized water into the filter cake, adjusting the concentration of the slurry, placing the filter cake into the tough-lined zirconia ceramic, adding a zirconia ceramic grinding medium and a dispersing agent, carrying out nanocrystallization grinding until the slurry d90 is less than 100 nm;

and S7, separating the ground slurry from the grinding medium, placing the slurry in a glass container, and drying and scattering the slurry to obtain the high-purity nano quartz powder.

In a preferred embodiment, in step S1, the mass ratio of the novel minerals to the zirconia ceramic balls and the deionized water is 1: (4-4.5): (1.0-1.5); the dispersant is sodium polycarboxylate, and the addition amount is 0.1-1.0% of the mass of the novel mineral; the diameter of the zirconia ceramic medium is 0.8-2.0 mm.

In a preferred embodiment, in step S1, the milling time in the media-stirring mill is 40min to 4 h;

the raw materials of the invention are selected from natural minerals, wherein carbon and silicon dioxide grow together, and the first grinding can separate the carbon and the silicon dioxide, thereby being beneficial to the subsequent steps of carbon removal and impurity removal.

In a preferred embodiment, in step S2, the solid-to-liquid ratio is adjusted to a solid content of 1-5%; the addition amount of the absolute ethyl alcohol is 5-30% of the novel mineral substance;

practical verification shows that after the novel mineral is ground, the difference between the sedimentation rates of silicon dioxide and carbon is large, and the superfine silicon dioxide has repulsion in water to form suspension which is difficult to precipitate and is positioned on the upper layer of the layered solution; the carbon flocculates to form larger particles, and then the larger particles are settled in the lower layer of the solution; in the scheme of the invention, the density of water can be effectively reduced by adding absolute ethyl alcohol, so that the carbon settling speed is accelerated, and carbon and silicon dioxide are further separated.

In a preferred embodiment, in step S3, the oxidant is one or more of sodium hypochlorite, chlorine dioxide and hydrogen peroxide;

the adding amount of the oxidant is 3-5 times of the volume of the upper-layer slurry; the reaction temperature is 30-95 ℃, and the reaction time is 2-100 h; the preferable reaction temperature is 70-90 ℃, and the reaction time is 5-8 h; the oxidant can effectively remove a small amount of un-settled carbon, and a better decarburization effect is achieved.

In a preferred embodiment, in step S4, the centrifugation speed is 10000-12000 r/min, and the centrifugation time is 1-3 min;

after decarburization, the upper layer of the solution is suspended silicon dioxide with small particle size, and the silicon dioxide can be effectively collected through high-speed centrifugation, and impurities dissolved in water can be removed.

In a preferred embodiment, in step S5, the acid solution added is hydrochloric acid and/or sulfuric acid, the mass concentration is 10 to 30%, the reaction temperature is 20 to 95 ℃, and the reaction time is 1 to 240 hours; the preferable reaction temperature is 70-90 ℃, and the reaction time is 3-5 h;

the acid washing can remove inorganic pollutants in the silicon dioxide, including impurities such as iron, calcium and the like, and the acid liquor can be removed without introducing new impurities by washing with deionized water.

In a preferred embodiment, in step S6, the adjusting the slurry concentration means adjusting the solid content of the slurry to 15-30%; the grinding medium is zirconia ceramic with the diameter of 0.1-0.2mm, and the mass of the medium is 5-7 times of that of the filter cake obtained in the previous step; the dispersing agent is polycarboxylic acid, and the adding amount of the dispersing agent is 0.5-2.0% of the mass of the filter cake obtained in the previous step;

in a preferred embodiment, in step S7, the drying temperature is 20 ℃ to 150 ℃; the preferred drying temperature is 105 ℃ to 120 ℃.

Compared with the prior art, the invention has the advantages that:

1. the novel mineral used in the method is a natural mineral with silicon dioxide and carbon as main components, and has huge reserves and stable performance.

2. The preparation method is simple and easy to operate, and compared with the conventional method for preparing quartz powder, the method has the advantages of low cost, easily obtained raw materials and low energy consumption; the layered purification method has the obvious advantages of simplicity, less impurities and high preparation efficiency, and provides a new way for preparing high-purity nano quartz powder.

3. High purity nano quartz powder, d₉₀＜100nm，SiO₂The content is more than 99.9 percent, and the method can be widely applied to various fields of biology, medicine, construction, spice, fiber, energy storage and the like.

Drawings

These and/or other aspects and advantages of the present invention will become more apparent and more readily appreciated from the following detailed description of the embodiments of the invention, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a thermal analysis curve of the novel mineral of the present invention;

FIG. 2 is an X-ray diffraction pattern of the novel mineral of the present invention;

FIG. 3 is a graph and a curve of the novel mineral of the present invention after being dispersed in alcohol, wherein (A) is a Scanning Electron Microscope (SEM) with a magnification (Mag) of 20.00KX, and (B) is a SEM with a magnification (Mag) of 1.00 KX; (C) is the X-ray energy spectrum in the square frame line area in the graph (B); (D) is a table of element mass percent and atom percent;

FIG. 4 is a scanning electron micrograph of the novel mineral of the present invention after ultrasonic cleaning treatment, wherein (A) the magnification (Mag) is 5.40KX, and (B) the magnification (Mag) is 6.00 KX;

fig. 5 shows that in the step S2, after absolute ethyl alcohol was added to the dispersion slurry, the solution was clearly separated, the lower layer was black carbon, and the upper layer was silica.

FIG. 6 is an electron microscope image of the high purity nano quartz powder prepared by the present invention.

Detailed Description

For a better understanding of the present invention for those skilled in the art, the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments, but it should be understood that the scope of the present invention is not limited to the specific embodiments.

The experimental procedures used in the following examples are all conventional procedures unless otherwise specified.

Materials, reagents and the like used in the following examples are commercially available unless otherwise specified.

Research on novel mineral composition

The novel mineral is black and is taken from Fengcheng county, Yichun city, Jiangxi province. The component research method and the specific process are as follows.

First, thermal analysis

The atmosphere for the thermal analysis of the sample was air, and the sample was loaded using a Pt crucible as the sample stage. TG, DTG and DSC curves of the sample were obtained at a temperature rise rate of 10 ℃/min as shown in FIG. 1. The image clearly shows that there are two main decomposition stages of the mineral during the temperature rise to 1000 ℃. The first stage of sample decomposition is at 25 ℃ to 200 ℃, which appears as a bulge on the DSC curve, as an endothermic reaction. This stage involves both the evaporation of a small amount of water from the sample and the dehydroxylation of the sample. As can be seen from the analysis of the image data in fig. 1, the mass percentage of water and hydroxyl groups contained in the sample was 1.05%. The second stage of decomposition of the sample is between 420 ℃ and 720 ℃, which is represented by a depression on the DSC curve, is an exothermic reaction, mainly associated with oxidation and combustion of carbon within the sample. The peak value of the exothermic peak at the stage is 625.9 ℃ as can be seen from the DSC curve, namely the oxidation rate of carbon in the sample is maximum at the temperature, and the exothermic quantity can reach 7.531 mW/mg. Meanwhile, the DTG curve shows that the mass percent change rate of the sample reaches the fastest value of-2.17%/min at 620.7 ℃. The loss on ignition ratio is calculated by a TG curve, and the loss of the mass percent of the sample at the stage is 20.34 percent, namely the sample contains the simple substance carbon with corresponding proportion.

Two, X-ray diffraction analysis

The X-ray diffraction analysis (XRD) mainly aims at the analysis of crystalline substances in minerals, and the components of the crystalline substances in the minerals and the content of each component can be obtained by analyzing diffraction peaks of an XRD pattern. The invention carries out X-ray diffraction scanning on a mineral sample with the 2 theta of 10-80 degrees to obtain a graph 2, and can determine through the graph 2: crystalline substances within minerals are quartz, kaolinite, gypsum and pyrite.

By further analysis of the XRD pattern in fig. 2, the crystal planes having miller indices (001), (100), (101), (200), (004), (104), (213), (204), (312), (223), (204), (223), (202), (311), (314), (321), (206) can be identified from the diffraction peaks in the pattern. Through comparison with an open database, the components of the product can be respectively quartz, pyrite, kaolinite and mica. The content of each component can be calculated by analyzing the intensity of the diffraction peak, and the mass fraction of each component is shown in table 1.

TABLE 1 compositions and mass fractions of crystalline substances in novel minerals

It can be seen that the crystalline component of the mineral is mainly quartz, with small amounts of pyrite, kaolinite and mica as impurities.

Third, microscopic analysis

Microscopic analysis mainly uses a combination of Scanning Electron Microscopy (SEM) and X-ray energy spectroscopy (EDS) to test the structure and element distribution of a sample. The test samples are raw mineral ores and treated mineral samples, and the treatment methods of the minerals comprise ultrasonic cleaning, high-temperature decarbonization, chemical decarbonization and chemical silica removal. By observing the above five test samples, it is possible to comprehensively analyze the microscopic composition of the minerals and investigate the suitability of the corresponding treatment method.

First, the morphology of the raw ore was observed using SEM, and the element content thereof was analyzed using EDS. In order to observe the mineral without destroying its basic structure, the mineral was dispersed in alcohol as it is, and the dispersion was simply shaken and then dropped on an aluminum foil to prepare a scanning electron microscope sample for observation. As shown in fig. 3(a) and (B), the mineral is stacked from a plurality of fragments, and there are a large number of voids and holes. These bulk structures have rounded depressions and streaks on their surface, which may be due to bio-etching. In addition to the massive structure, a large number of rods are present on the surface of the mineral, with diameters of 50-100nm and lengths of 500nm-1 μm.

Further EDS spectrum analysis was performed on the region in the block diagram in fig. 3(B), resulting in fig. 3(C) and fig. 3 (D). Since the penetration depth of the X-ray spectral analysis is 1.5 μm, the elemental analysis is mainly performed on the surface layer of the sample. As can be seen from fig. 3(C), the main elements in the mineral are C, O, Al and Si, wherein the content of C is the highest and accounts for 42.51% by mass, and the content of Al is the lowest and accounts for 4.64% by mass.

The mass percentage of the C element obtained by EDS energy spectrum scanning is far higher than 20.34% by combining the results of thermal analysis and XRD, and the carbon element is mainly enriched on the surface of the mineral or in some special structures, but is not uniformly distributed in the mineral structure. Wherein carbon and quartz grow together, and the carbon in the mineral structure can be removed by adding an oxidant into the slurry and controlling the reaction temperature and time.

In order to observe the inner layer structure of the mineral more carefully and clearly, the invention uses the ultrasonic cleaning method to separate the scraps and impurities on the surface of the mineral particles, the mineral sample is dispersed in alcohol, ultrasonic cleaning is carried out for 15min, and the sample is dripped on a silicon wafer to prepare a scanning electron microscope sample for observation, the obtained scanning electron microscope image is shown in figure 4, after the ultrasonic cleaning, the scraps and rod-shaped objects on the surface of the mineral are basically eliminated, and the ultrasonic cleaning is also shown to be capable of effectively separating the scraps and impurities on the surface of the mineral. Fig. 4(a) shows that there are circular depressions of varying sizes on the mineral particles, and that there are mesoporous and microporous structures. Fig. 4(B) also shows that there are rounded depressions on the mineral particles and that there are nicks and cracks. Therefore, in the scheme of the invention, in order to better achieve the effect of removing impurities, after the decarburization step, the precipitate is obtained by high-speed centrifugal precipitation and then treated by acid liquor in a polytetrafluoroethylene container, so that a large amount of impurities and scraps can be removed. After treatment, the acid liquor can be removed by washing with deionized water.

Fourthly, analysis of specific surface area and pore space

The specific surface area and pore size analysis is mainly to detect the specific surface area of a sample and the pore structure of the sample by using a specific surface area and pore size analyzer. The algorithm used for the detection is mainly BET. The test sample was as-mineral, and after drying the sample at 115 ℃, the BET specific surface area test was performed using nitrogen as an adsorbate.

The BET specific surface area of the mineral obtained as such was tested to be 5.2684m²(iv) total pore volume of 0.028110cm³The adsorption average pore diameter is 213.421 angstroms, and the desorption average pore diameter is 201.633 angstroms.

In conclusion, the novel mineral comprises a crystalline component and an amorphous component, wherein the crystalline component accounts for 78.61% of the mass fraction of the mineral, and the amorphous component accounts for 21.39% of the mass fraction of the mineral; the crystal components comprise quartz, pyrite, kaolinite and mica, the mass fraction of the quartz accounts for 91% of that of the crystal components, the amorphous substances comprise water, simple substance carbon and organic substances, the content of the carbon is 20.34%, and the carbon and the quartz grow together. The high-purity nano quartz powder can be obtained by removing carbon, organic matters and impurities in the quartz powder.

Example 1

1. The analyzed novel minerals are used as raw materials, and are mixed with zirconia ceramic balls and water according to the mass ratio of 1: 4: 0.8, adding a novel sodium polycarboxylate dispersant with the mineral mass of 0.1 percent, and grinding for 4 hours in a medium stirring mill; the diameter of the zirconia ceramic medium is 0.8-2.0mm, so that the powder d₅₀＜2μm，d₉₀Less than 20 mu m to obtain dispersed slurry;

2. separating the prepared dispersion slurry from the ceramic medium, adding deionized water into the dispersion slurry, adjusting the solid content to 1%, adding anhydrous ethanol with the novel mineral substance content of 5%, standing for 30min, and taking the upper-layer slurry;

3. placing the upper layer slurry in a glass container, adding sodium hypochlorite which is 3 times of the upper layer slurry in mass for oxidation and decarbonization at the temperature of 30 ℃ for 100 hours to obtain reaction slurry;

4. centrifuging the reaction slurry with a high-speed centrifuge at 10000r/min for 3min, pouring out clear liquid, and taking out precipitate;

5. placing the precipitate in a polytetrafluoroethylene container, adding hydrochloric acid with the mass concentration of 10%, and reacting at the temperature of 20 ℃ for 240 h; filtering the slurry after the reaction is finished, and washing the slurry with deionized water until the pH value is more than 6 to obtain a filter cake;

6. adding deionized water into the filter cake, adjusting to a mass concentration of 15%, placing into the tough-lined zirconia ceramic, adding zirconia ceramic grinding medium with a diameter of 0.1-0.2mm which is 5 times of the mass of the filter cake, adding polycarboxylic acid dispersant which is 0.5% of the mass of the filter cake, performing nanocrystallization grinding, and grinding to slurry d₉₀＜100nm；

7. Separating the ground slurry from the grinding medium, placing the slurry in a glass container, drying the slurry at the temperature of 20 ℃, and scattering the slurry to obtain the high-purity nano quartz powder.

Wherein, after absolute ethyl alcohol is added into the dispersed slurry, the solution is obviously layered, and the superfine silicon dioxide has repulsion force in water to form suspension which is difficult to precipitate and is positioned on the upper layer of the layered solution; the carbon flocculates to form larger particles, which settle in the lower layer of the solution. As shown in fig. 5, the black lower layer is carbon, and the suspension of the upper layer is silicon dioxide, which can be effectively separated from carbon.

The microscopic image of the prepared high-purity nano quartz powder is shown in FIG. 6.

Example 2

1. Taking novel minerals in Fengcheng county, Yichun city, Jiangxi province as raw materials, and mixing the novel minerals, zirconia ceramic balls and water according to a mass ratio of 1: 5: 2.0, adding a novel sodium polycarboxylate dispersant with the mineral mass of 1.0 percent, and grinding for 40min in a medium stirring mill; the diameter of the zirconia ceramic medium is 0.8-2.0mm, so that the powder d₅₀＜2μm，d₉₀Less than 20 mu m to obtain dispersed slurry;

2. separating the prepared dispersion slurry from the ceramic medium, adding deionized water into the dispersion slurry, adjusting the solid content to be 5%, adding anhydrous ethanol with the mass of 30% of the novel mineral substance, standing for 10min, and taking the upper-layer slurry;

3. placing the upper layer slurry into a glass container, and adding ClO with the mass 5 times that of the upper layer slurry₂Carrying out oxidation decarbonization at the temperature of 95 ℃ for 2 hours to obtain reaction slurry;

4. centrifuging the reaction slurry by a high-speed centrifuge at 12000r/min for 1min, pouring out clear liquid, and taking out precipitate;

5. placing the precipitate in a polytetrafluoroethylene container, adding sulfuric acid with the mass concentration of 30%, and reacting for 1h at the temperature of 95 ℃; filtering the slurry after the reaction is finished, and washing the slurry with deionized water until the pH value is more than 6 to obtain a filter cake;

6. adding deionized water into the filter cake, adjusting the mass concentration to 30%, placing the filter cake in the tough-lined zirconia ceramic,adding zirconium oxide ceramic grinding medium with diameter of 0.1-0.2mm and weight 7 times of that of the filter cake, adding polycarboxylic acid dispersant in 2.0 wt% of the filter cake, grinding to slurry d₉₀＜100nm；

7. Separating the ground slurry from the grinding medium, placing the slurry in a glass container, drying the slurry at 150 ℃, and scattering the slurry to obtain the high-purity nano quartz powder.

Example 3

1. Taking novel minerals in Fengcheng county, Yichun city, Jiangxi province as raw materials, and mixing the novel minerals, zirconia ceramic balls and water according to a mass ratio of 1: 4.5: 1.0, adding a novel sodium polycarboxylate dispersant with the mineral mass of 0.5 percent, and grinding for 2 hours in a medium stirring mill; the diameter of the zirconia ceramic medium is 0.8-2.0mm, so that the powder d₅₀＜2μm，d₉₀Less than 20 mu m to obtain dispersed slurry;

2. separating the prepared dispersion slurry from the ceramic medium, adding deionized water into the dispersion slurry, adjusting the solid content to be 3%, adding 20% of absolute ethyl alcohol of the novel mineral substance, standing for 20min, and taking the upper-layer slurry;

3. placing the upper layer slurry in a glass container, adding a mixture of sodium hypochlorite and hydrogen peroxide in an amount which is 4 times the mass of the upper layer slurry, and oxidizing to remove carbon at 90 ℃ for 4 hours to obtain reaction slurry;

4. centrifuging the reaction slurry by a high-speed centrifuge at 11000r/min for 2min, pouring out clear liquid, and taking out precipitate;

5. placing the precipitate in a polytetrafluoroethylene container, adding hydrochloric acid with the mass concentration of 20%, and reacting at the temperature of 90 ℃ for 2 hours; after the reaction is finished, filtering the slurry, and washing the slurry with deionized water until the pH value is more than 6 to obtain a filter cake;

6. adding deionized water into the filter cake, adjusting to mass concentration of 20%, placing into tough-lined zirconia ceramic, adding zirconia ceramic grinding medium with diameter of 0.1-0.2mm 6 times of the filter cake, adding polycarboxylic acid dispersant 1.0% of the filter cake, grinding to slurry d₉₀＜100nm；

7. Separating the ground slurry from the grinding medium, placing the slurry in a glass container, drying the slurry at 100 ℃, and scattering the slurry to obtain the high-purity nano quartz powder.

Claims

1. A preparation method of high-purity nano quartz powder is characterized in that,

the method is characterized by taking minerals as raw materials, grinding the minerals twice by adopting zirconia ceramic balls, layering the ground minerals by using absolute ethyl alcohol, decarbonizing an oxidant, and removing impurities by acid washing to obtain the zirconia ceramic ball;

the mineral comprises a crystalline component and an amorphous component, wherein the crystalline component accounts for 78.61% of the mass fraction of the mineral, and the amorphous component accounts for 21.39% of the mass fraction of the mineral; the crystalline component comprises quartz, pyrite, kaolinite and mica, wherein the quartz accounts for 91% of the mass fraction of the crystalline component; the amorphous substance comprises water, simple substance carbon and organic substances, wherein the simple substance carbon accounts for 95.1% of the mass fraction of the amorphous component.

2. The method for preparing high purity nano quartz powder according to claim 1, comprising the steps of:

s1, mixing the minerals with zirconia ceramic balls and deionized water uniformly, adding a dispersing agent, and grinding in a medium stirring mill until powder d₅₀＜2μm，d₉₀Less than 20 microns, and separating the slurry from the grinding balls to obtain dispersed slurry;

s5, placing the precipitate into a polytetrafluoroethylene container, adding acid liquor to react fully, filtering slurry after the reaction is finished, and washing with deionized water until the pH value is more than 6 to obtain a filter cake;

s6, adding deionized water into the filter cake, adjusting the concentration of the slurry, placing the filter cake into the tough-lined zirconia ceramic, adding the zirconia ceramic grinding medium and dispersingGrinding the mixture to slurry d₉₀＜100nm；

3. The method for preparing high-purity nano quartz powder according to claim 2, wherein in the step S1, the mass ratio of the minerals to the zirconia ceramic balls to the deionized water is 1: (4-4.5): (1.0-1.5); the dispersant is sodium polycarboxylate, and the addition amount is 0.1-1.0% of the mineral mass; the diameter of the zirconia ceramic medium is 0.8-2.0 mm.

4. The method for preparing high purity nano quartz powder according to claim 2, wherein in the step S1, the grinding time in the media stirring mill is 40min-4 h.

5. The method for preparing high-purity nano quartz powder according to claim 2, wherein in the step S2, the solid-liquid ratio is adjusted to be 1-5% of solid content; the addition amount of the absolute ethyl alcohol is 5-30% of the mass of the mineral substance.

6. The method for preparing high purity nano quartz powder according to claim 2, wherein in the step S3, the oxidant is one or more of sodium hypochlorite, chlorine dioxide and hydrogen peroxide; the adding amount of the oxidant is 3-5 times of the volume of the upper-layer slurry; the reaction temperature is 30-95 ℃, and the reaction time is 2-100 h.

7. The method for preparing high purity nano quartz powder according to claim 2, wherein in step S4, the centrifugal rotation speed is 10000-12000 r/min, and the centrifugal time is 1-3 min.

8. The method for preparing high-purity nano quartz powder according to claim 2, wherein the acid solution added in step S5 is hydrochloric acid and/or sulfuric acid, the mass concentration is 10-30%, the reaction temperature is 20-95 ℃, and the reaction time is 1-240 h.

9. The method for preparing high-purity nano quartz powder according to claim 2, wherein in the step S6, the adjustment of the slurry concentration means that the solid content of the slurry is adjusted to 15-30%; the grinding medium is zirconia ceramic with the diameter of 0.1-0.2mm, and the mass of the medium is 5-7 times of that of the filter cake; the dispersant is polycarboxylic acid, and the addition amount of the dispersant is 0.5 to 2.0 percent of the mass of the filter cake.

10. The method for preparing high purity nano quartz powder according to claim 2, wherein the drying temperature in the step S7 is 20 ℃ to 150 ℃.