Preparation method of high-purity quartz sand

Abstract

The invention provides a preparation method of high-purity quartz sand, and relates to the technical field of purification of quartz sand. The preparation method comprises the following steps that quartz sand is placed in an energy-gathered electrode device, energy is focused through an external power source, penetration and impact effects are generated at the tip end of an energy-gathered electrode to conduct energy-gathered electrode blasting, impurities in the quartz sand are separated from a quartz matrix, and primarily purified quartz sand is obtained; and mixing the primarily purified quartz sand with an electrolyte solution, and carrying out grinding and washing treatment by utilizing an energy-gathered electrode, so that impurities adhered to the surface of the primarily purified quartz sand are separated from a quartz matrix, and the high-purity quartz sand is obtained. The high-purity quartz sand is obtained after the energy-gathered electrode blasting-energy-gathered electrode grinding and washing combined process is adopted, the purity of the high-purity quartz sand can reach 5N or above, that is, the purity of the finally obtained high-purity quartz sand is 99.9990% or above, especially the Fe content is smaller than 1 ppm, and the Al content is smaller than 5 ppm.

Description

Technical Field

[0001] The invention relates to the technical field of quartz sand purification, and in particular to a method for preparing high-purity quartz sand. Background Art

[0002] High-purity quartz sand is widely used in photovoltaic, semiconductor, solar energy, optical fiber, optical communication, electric light source, aerospace and other fields. It is also an indispensable raw material for laboratory glassware, bioactive glass and other high-demand application equipment. High-purity quartz sand is mainly composed of SiO2, and the total amount of impurities must be strictly controlled below 100ppm. Among them, ordinary grade: SiO2 ≥ 99.5% (generally used in metallurgy, glass industry and other fields); mid-to-high-end grade: SiO2 ≥ 99.9% (generally used in photovoltaic, optical fiber and other fields); cutting-edge grade: SiO2 ≥ 99.999% (generally used in semiconductor grade and other fields).

[0003] In nature, although quartz is widely distributed, high-purity quartz is very rare. Quartz sand is mainly composed of SiO2, and is often doped with some impurity elements, mainly including non-metallic elements B, P, C, O, and metal elements Fe, Al, Ca, Ti, Mn, V, Cu, Cr, etc. Key impurity elements such as Al, Fe, K, Na, B and other elements have a particularly significant impact on semiconductor performance. According to the size, formation, and distribution characteristics of the impurities, they can be mainly divided into: 1) impurities adhering to the surface of quartz; 2) structural impurities doped in the quartz lattice; 3) submicron-level fine-grained inclusion impurities. With the rapid development of solar photovoltaic cells, semiconductor materials and military industries in recent years, the demand for high-purity quartz has increased dramatically, and the purification technology of high-purity quartz has also become a technical problem that needs to be broken through.

[0004] At present, the traditional quartz sand purification process is: water washing-acid leaching-roasting-water crushing-secondary acid leaching. In the traditional purification process, most of the gangue minerals and gas-liquid inclusions in the quartz raw materials can be dissociated or destroyed and removed, but the removal of lattice impurities is extremely difficult, and the purification limit of this process has been reached after acid leaching. If the amount of hydrogen and fluorine, which are seriously polluting the environment, is excessively increased, the temperature is increased, or the time is extended, it will only cause the overall dissolution of the quartz minerals, reduce the concentrate yield, and will not have a purification effect on the impurity elements in the lattice. Therefore, for the purification of quartz raw materials with lattice impurity content, it is necessary to develop a new deep purification process.

[0005] At present, the most effective method for removing lattice impurities is mainly the chlorination roasting process. Chlorination roasting, also known as chlorination degassing, utilizes the chemical potential gradient generated on the surface and inside of particles under the action of a high-concentration chlorinating agent to promote the diffusion of gas-liquid inclusions. There are significant differences in the action modes and effects of different chlorinating agents on lattice impurities. For example, when using different chlorinating agents such as dry hydrogen chloride (HCl), dry chlorine (Cl2), and a mixed gas of dry chlorine and hydrogen chloride (Cl2 / HCl) to carry out high-temperature chlorination purification of quartz sand, it shows that high-temperature chlorination treatment has obvious purification effects on Na, Fe, and K, but the removal effect of Al in the quartz sand lattice is very poor, and it also causes relatively serious pollution to the atmosphere and water bodies.

[0006] The combined method of traditional physical (such as flotation, calcination, etc.) and chemical (acid leaching) methods to refine high-purity quartz sand has become the current preference. However, the current purification methods have limited ability to remove impurities in quartz and have certain limitations in the actual operation process. At the same time, existing physical methods (such as mechanical crushing) are difficult to accurately act on lattice impurities.

[0007] Therefore, to solve the current technical problems and achieve controllable high-purity quartz resources and available materials, it is urgent to provide a preparation method for high-purity quartz sand with a simple process, high efficiency, stable product quality, high purity, low production cost, zero wastewater discharge, and no environmental pollution.

[0008] In view of this, the present invention is specifically proposed. Summary of the Invention

[0009] The purpose of the present invention is to provide a preparation method for high-purity quartz sand. The present invention adopts a combined process of polyenergy electrode blasting - polyenergy electrode grinding and washing to obtain high-purity quartz sand, and its purity can reach 5N or above, that is, the purity of the finally obtained high-purity quartz sand is above 99.9990%, especially the Fe content < 1 ppm and the Al content < 5 ppm.

[0010] In order to achieve the above object of the present invention, the following technical solutions are specifically adopted:

[0011] In the first aspect, the present invention provides a preparation method for high-purity quartz sand, and the preparation method includes the following steps:

[0012] Place the quartz sand in a polyenergy electrode device, focus the energy through an external power supply, and generate a penetration and impact effect at the tip of the polyenergy electrode for polyenergy electrode blasting, so that the impurities in the quartz sand are separated from the quartz matrix to obtain initially purified quartz sand;

[0013] Mix the initially purified quartz sand with an electrolyte solution, and use the polyenergy electrode for grinding and washing treatment to separate the impurities adhering to the surface of the initially purified quartz sand from the quartz matrix to obtain high-purity quartz sand.

[0014] Preferably, the impurities include any one or a combination of at least two of aluminum oxide, iron oxide, titanium dioxide, calcium oxide, magnesium oxide, potassium oxide or sodium oxide.

[0015] Preferably, the energy-gathering electrode is obtained by calcining lanthanum oxide, vanadium oxide and tungsten oxide.

[0016] Preferably, the mass ratio of the lanthanum oxide, vanadium oxide and tungsten oxide is (0.1 - 2):(0.1 - 2):(7 - 9).

[0017] Preferably, the preparation method of the energy-gathering electrode includes: mixing lanthanum oxide, vanadium oxide and tungsten oxide, placing them in a mold, and performing calcination to obtain the energy-gathering electrode.

[0018] Preferably, the temperature of the calcination is 2000 - 2200 °C, and the time of the calcination is 6 - 18 h.

[0019] Preferably, the quartz sand needs to be pretreated as follows before the energy-gathering electrode explodes:

[0020] Crush the quartz ore to a particle size of less than 10 cm, and successively perform water washing, drying and grinding to obtain quartz sand with a particle size of 60 - 180 mesh.

[0021] Preferably, during the explosion of the energy-gathering electrode, the crystal form of the quartz changes, and the crystal form of the quartz changes from α-quartz to β-quartz.

[0022] Preferably, the energy of the energy-gathering electrode during the explosion of the energy-gathering electrode is 3000 - 8000 V, and the time of the explosion of the energy-gathering electrode is 10 - 60 s.

[0023] Preferably, the following post-treatment is also required after the explosion of the energy-gathering electrode:

[0024] After discharging the separated impurities through the impurity channel in the energy-gathering electrode device, the initially purified quartz sand is collected.

[0025] Preferably, the mass ratio of the initially purified quartz sand to the electrolyte solution is 1:(3 - 8).

[0026] Preferably, the concentration of the electrolyte solution is 200 - 300 g / L.

[0027] Preferably, the solute in the electrolyte solution is selected from any one or a combination of at least two of magnesium chloride, ferrous sulfate or vitamin C.

[0028] Preferably, the solvent in the electrolyte solution is selected from distilled water and / or ultrapure water.

[0029] Preferably, the abrasive washing treatment is specifically as follows: the high-energy focusing generated by the energy-gathering electrode forms a vortex in the solution, thereby performing abrasive washing treatment on the quartz sand.

[0030] Preferably, the energy of the energy-gathering electrode is 300 - 800V.

[0031] Preferably, the abrasive washing treatment is carried out under stirring, and the rotation speed of the stirring is 100 - 500 rpm;

[0032] Preferably, the temperature of the abrasive washing treatment is 70 - 90 °C.

[0033] Preferably, the time of the abrasive washing treatment is 0.5 - 5 h.

[0034] Preferably, the abrasive washing treatment is carried out in a polytetrafluoroethylene reaction kettle.

[0035] Preferably, after the abrasive washing treatment, the following purification treatment steps are further included:

[0036] Filter the mixed solution after the abrasive washing treatment to separate and obtain an electrolyte solution and quartz sand solids; after washing the quartz sand solids to neutrality and drying, obtain the high-purity quartz sand.

[0037] Preferably, the removal rate of the impurities is more than 99.5%.

[0038] Preferably, in terms of silicon dioxide, the purity of the high-purity quartz sand is more than 99.9990%.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] (1) By focusing energy through an external power supply, the present invention generates a penetration and impact effect at the tip of the electrode for energy-gathering electrode blasting, separating the impurities in the quartz sand from the quartz matrix. In view of the physical property differences between conductive impurities and quartz, the binding force of the impurities is preferentially damaged. On the basis of avoiding damage to the quartz matrix, the impurities in the lattice of the quartz sand are removed to obtain initially purified quartz sand.

[0041] (2) Through the physical abrasive washing of the energy-gathering electrode and the chemical reaction of the electrolyte solution on the initially purified quartz sand, the two cooperate synergistically to achieve non-corrosive and highly efficient stripping of the surface-adhering impurities on the surface of the quartz sand, thereby obtaining high-purity quartz sand with a purity of 5N or above. That is, the purity of the finally obtained high-purity quartz sand is more than 99.9990%.

[0042] (3) The overall process of the preparation method of the high-purity quartz sand of the present invention does not require pickling, alkali washing or high-temperature calcination treatment. Both the electrolyte solution and the washing water can be recycled. The sludge is dried and transported out. The overall process can achieve zero wastewater discharge and has excellent recyclability and environmental friendliness. Detailed implementation manners

[0043] Unless otherwise defined herein, scientific and technical terms used in conjunction with the present invention shall have the meanings commonly understood by those of ordinary skill in the art. The meanings and scopes of the terms should be clear. However, in any case of potential ambiguity, the definitions provided herein shall prevail over any dictionary or extrinsic definition. In this application, unless otherwise specified, the use of "or" means "and / or". In addition, the use of the term "comprising" and other forms is non-restrictive.

[0044] It should be noted that specific details are set forth in the following description to facilitate a thorough understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific implementation manners disclosed below.

[0045] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0046] In order to achieve the above object of the present invention, the following technical solutions are specifically adopted:

[0047] In the first aspect, the present invention provides a preparation method of high-purity quartz sand, and the preparation method includes the following steps:

[0048] Place the quartz sand in a poly-energy electrode device, focus energy through an external power supply, generate a penetration and impact effect at the tip of the poly-energy electrode for poly-energy electrode blasting, so that the impurities in the quartz sand are separated from the quartz matrix to obtain preliminarily purified quartz sand;

[0049] Mix the preliminarily purified quartz sand and an electrolyte solution, and perform grinding and washing treatment using the poly-energy electrode, so that the impurities adhering to the surface of the preliminarily purified quartz sand are separated from the quartz matrix to obtain high-purity quartz sand.

[0050] First, use the shaped charge electrode blasting. Under the powerful non-conductor penetration effect and impact, it has a selective affinity for non-silicon impurities with better conductivity on the surface of quartz, enabling this energy effect to have a special peeling and removal effect on non-silicon impurities and silicon. The same powerful non-conductor penetration effect and impact also create cracks and holes in the quartz inclusions and lattice, resulting in the guiding discharge, peeling, and removal of non-silicon impurities with better conductivity inside the inclusions and lattice. The organic impurities in the quartz are oxidized and decomposed into CO2 under the powerful energy effect of the shaped charge electrode. The purified quartz is discharged from the defined channel in the shaped charge electrode device, and the impurities are excluded from the impurity channel in the shaped charge electrode device, thus separating the impurities in the quartz sand from the quartz matrix to obtain the initially purified quartz sand.

[0051] Secondly, then subject the initially purified quartz sand to physical grinding and washing by the shaped charge electrode in combination with the chemical reaction of the electrolyte solution, and cooperate synergistically to achieve the corrosion-free and highly efficient peeling of the surface impurities of the quartz sand. During the energy grinding and washing process of the shaped charge electrode, the internal blasting stress of the original shaped charge electrode energy is instantly released, making the previously generated cracks wider and deeper, exposing more impurities on the quartz surface, and the shaped charge electrode grinding and washing can remove most or all of the gas-liquid inclusions in the quartz silicon ore.

[0052] In summary, the present invention adopts the combined process of shaped charge electrode blasting - shaped charge electrode grinding and washing to obtain high-purity quartz sand, the purity of which can reach 5N or above, that is, the purity of the finally obtained high-purity quartz sand is above 99.9990%, especially the Fe content < 1 ppm and the Al content < 5 ppm.

[0053] As an optional implementation method, the impurities include any one or a combination of at least two of aluminum oxide, iron oxide, titanium dioxide, calcium oxide, magnesium oxide, potassium oxide, or sodium oxide.

[0054] It should be noted that during the blasting instant high-temperature oxidation process of the electrode point generated by the energy effect of the shaped charge electrode, the activity of the impurities in the quartz increases, causing the divalent iron and aluminum ions inside the quartz to oxidize and increase in valence, resulting in charge imbalance. These ions with increased valence are thermodynamically very unstable, driving their diffusion to the quartz surface to form new minerals. At the same time, during the crystal form transformation process of the quartz, channels for the diffusion of impurities such as iron and aluminum are opened, and the powerful non-conductor penetration effect and impact promote the outward migration and enrichment of impurities such as iron, aluminum, and other metal impurities in the inclusions and lattice to the quartz surface.

[0055] As an optional implementation method, the shaped charge electrode is obtained by calcining lanthanum oxide, vanadium oxide, and tungsten oxide.

[0056] In the present invention, the energy-gathering electrode is obtained by calcining lanthanum oxide, vanadium oxide, and tungsten oxide. Through the energy-gathering electrode material, electric energy is concentrated on the quartz lattice to generate a directional shock wave, thereby precisely splitting impurities.

[0057] As an alternative embodiment, the mass ratio of lanthanum oxide, vanadium oxide, and tungsten oxide is (0.1 - 2):(0.1 - 2):(7 - 9);

[0058] Among them, for lanthanum oxide, "0.1 - 2" can be, for example, 0.1, 0.2, 0.4, 0.5, 0.6, 0.8, 1, 1.2, 1.4, 1.5, 1.6, 1.8, 2, etc.;

[0059] Among them, for vanadium oxide, "0.1 - 2" can be, for example, 0.1, 0.2, 0.4, 0.5, 0.6, 0.8, 1, 1.2, 1.4, 1.5, 1.6, 1.8, 2, etc.;

[0060] Among them, for tungsten oxide, "7 - 9" can be, for example, 7, 7.2, 7.4, 7.5, 7.6, 7.8, 8, 8.2, 8.4, 8.5, 8.6, 8.8, 9, etc.

[0061] As a preferred embodiment, the mass ratio of lanthanum oxide, vanadium oxide, and tungsten oxide is 1:1:8.

[0062] As an alternative embodiment, the preparation method of the energy-gathering electrode includes:

[0063] Mix lanthanum oxide, vanadium oxide, and tungsten oxide, place them in a mold, and perform calcination to obtain the energy-gathering electrode.

[0064] As an alternative embodiment, the temperature of the calcination is 2000 - 2200 °C, and can be, for example, 2000 °C, 2020 °C, 2040 °C, 2050 °C, 2060 °C, 2080 °C, 2100 °C, 2120 °C, 2140 °C, 2150 °C, 2160 °C, 2180 °C, 2200 °C, etc.

[0065] As an alternative embodiment, the time of the calcination is 6 - 18 h, and can be, for example, 6 h, 6.5 h, 7 h, 7.5 h, 8 h, 8.5 h, 9 h, 9.5 h, 10 h, 10.5 h, 11 h, 11.5 h, 12 h, 12.5 h, 13 h, 13.5 h, 14 h, 14.5 h, 15 h, 15.5 h, 16 h, 16.5 h, 17 h, 17.5 h, 18 h, etc.

[0066] As an alternative embodiment, the quartz sand needs to be pretreated as follows before the energy-gathering electrode blasting:

[0067] The quartz ore is crushed to a particle size of less than 10 cm, and then washed, dried, and ground in sequence to obtain quartz sand with a particle size of 60-180 mesh.

[0068] As an optional implementation mode, the quartz ore is crushed to a particle size of less than 10 cm, for example, it can be 10 cm, 9 cm, 8 cm, 7 cm, 6 cm, 5 cm, 4 cm, 3 cm, 2 cm, 1 cm, etc.

[0069] As an optional implementation mode, the particle size of the quartz sand obtained after grinding is 60-180 mesh, for example, it can be 60 mesh, 70 mesh, 80 mesh, 90 mesh, 100 mesh, 110 mesh, 120 mesh, 130 mesh, 140 mesh, 150 mesh, 160 mesh, 170 mesh, 180 mesh, etc.

[0070] As an optional implementation mode, during the blasting of the energy-gathering electrode, the crystal form of the quartz changes, and the crystal form of the quartz changes from α-quartz to β-quartz.

[0071] It should be noted that the main metal impurities in the raw quartz ore are Fe, Al, Ca, K, Na, Ti, and Li, among which the Fe impurity content is the highest. These metal impurities mainly exist in impurity minerals such as hematite, muscovite, and apatite, and develop along microfractures. The occurrence inclusions are mainly in the form of gas-liquid two phases. In addition, the main component of the raw quartz ore is α-quartz. When the energy of the energy-gathering electrode for the blasting of the energy-gathering electrode is 3000-8000 V, the crystal form of the quartz can be changed from α-quartz to β-quartz.

[0072] As an optional implementation mode, the energy of the energy-gathering electrode for the blasting of the energy-gathering electrode is 3000-8000 V, for example, it can be 3000 V, 3500 V, 4000 V, 4500 V, 5000 V, 5500 V, 6000 V, 6500 V, 7000 V, 7500 V, 8000 V, etc.

[0073] As an optional implementation mode, the blasting time of the energy-gathering electrode is 10-60 s, for example, it can be 10 s, 15 s, 20 s, 25 s, 30 s, 35 s, 40 s, 45 s, 50 s, 55 s, 60 s, etc.

[0074] As an optional implementation mode, the removal rate of the impurities is more than 90%, for example, it can be 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, etc.

[0075] As an optional implementation mode, after the blasting of the energy-gathering electrode, the following post-treatment is also required:

[0076] After discharging the separated impurities through the impurity channel in the energy-gathering electrode device, the initially purified quartz sand is collected.

[0077] As an alternative embodiment, the mass ratio of the initially purified quartz sand to the electrolyte solution is 1:(3 - 8), for example, it can be 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, etc.

[0078] As an alternative embodiment, the concentration of the electrolyte solution is 200 - 300 g / L, for example, it can be 200 g / L, 210 g / L, 220 g / L, 230 g / L, 240 g / L, 250 g / L, 260 g / L, 270 g / L, 280 g / L, 290 g / L, 300 g / L, etc.

[0079] As an alternative embodiment, the solute in the electrolyte solution is selected from any one or a combination of at least two of magnesium chloride, ferrous sulfate, or vitamin C.

[0080] As an alternative embodiment, the solvent in the electrolyte solution is selected from distilled water and / or ultrapure water.

[0081] As an alternative embodiment, the grinding and washing treatment is specifically: the high - energy concentration generated by the energy - concentrating electrode forms a vortex in the solution, thereby performing the grinding and washing treatment on the quartz sand.

[0082] As an alternative embodiment, the energy of the energy - concentrating electrode is 300 - 800 V, for example, it can be 300 V, 350 V, 400 V, 450 V, 500 V, 550 V, 600 V, 650 V, 700 V, 750 V, 800 V, etc.

[0083] As an alternative embodiment, the grinding and washing treatment is carried out under stirring, and the rotation speed of the stirring is 100 - 500 rpm, for example, it can be 100 rpm, 150 rpm, 200 rpm, 250 rpm, 300 rpm, 350 rpm, 400 rpm, 450 rpm, 500 rpm, etc.

[0084] As an alternative embodiment, the temperature of the grinding and washing treatment is 70 - 90 °C, for example, it can be 70 °C, 72 °C, 74 °C, 75 °C, 76 °C, 78 °C, 80 °C, 82 °C, 84 °C, 86 °C, 88 °C, 90 °C, etc.

[0085] As an alternative embodiment, the time of the grinding and washing treatment is 0.5 - 5 h, for example, it can be 0.5 h, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h, etc.

[0086] As an alternative embodiment, the grinding and washing treatment is carried out in a polytetrafluoroethylene reaction vessel.

[0087] As an alternative embodiment, the following purification treatment steps are further included after the abrasive washing treatment:

[0088] Filter the mixed liquid after the abrasive washing treatment to separately obtain an electrolyte solution and quartz sand solids; after washing the quartz sand solids to neutrality, dry them to obtain the high-purity quartz sand.

[0089] As an alternative embodiment, the removal rate of the impurities is 99.5% or more, for example, it can be 99.500%, 99.600%, 99.700%, 99.800%, 99.900%, 99.950%, 99.990%, 99.999%, etc.

[0090] As an alternative embodiment, based on silicon dioxide, the purity of the high-purity quartz sand is 99.9990% or more, for example, it can be 99.9990%, 99.9991%, 99.9992%, 99.9993%, 99.9994%, 99.9995%, etc.

[0091] The present invention will be further described below through examples. Unless otherwise specified, the materials in the examples are prepared according to existing methods or directly purchased from the market.

[0092] Preparation Example 1

[0093] This preparation example provides a poly-energy electrode, and the poly-energy electrode is obtained by a preparation method:

[0094] Mix lanthanum oxide, vanadium oxide, and tungsten oxide with a mass ratio of 1:1:8, place them in a mold, and calcine at 2100 °C for 12 h to obtain the poly-energy electrode.

[0095] Preparation Example 2

[0096] This preparation example provides a poly-energy electrode, and the poly-energy electrode is obtained by a preparation method:

[0097] Mix lanthanum oxide, vanadium oxide, and tungsten oxide with a mass ratio of 0.4:0.6:9, place them in a mold, and calcine at 2000 °C for 16 h to obtain the poly-energy electrode.

[0098] Preparation Example 3

[0099] This preparation example provides a poly-energy electrode, and the poly-energy electrode is obtained by a preparation method:

[0100] Mix lanthanum oxide, vanadium oxide, and tungsten oxide with a mass ratio of 1.6:1.4:7, place them in a mold, and calcine at 2200 °C for 8 h to obtain the poly-energy electrode.

[0101] Test Example 1

[0102] Electrode Performance Test

[0103] Test samples: The energy - gathering electrodes provided in Preparation Examples 1 - 3.

[0104] Test items: Test the maximum areal energy density and volumetric energy density of each sample electrode when the areal power density is 1.0 mW·cm -2 .

[0105] The test results are shown in Table 1 below:

[0106] Table 1

[0107]

[0108] From the data in Table 1, it can be seen that the maximum instantaneous local energy - gathering energy density of the energy - gathering electrode obtained by calcining lanthanum oxide, vanadium oxide and tungsten oxide provided by the present invention is 67000 mWh·cm -2 Above, the ratio of Preparation Example 1 is the optimal solution, and its maximum areal energy density can reach 68000 mWh·cm -2 . Therefore, when the electric energy acts on the quartz lattice intensively, a directional shock wave with a certain intensity can be generated, so as to accurately split the impurities.

[0109] The chemical composition tables of the original quartz ore provided in the following examples are shown in Table 2 below:

[0110] Table 2

[0111] Serial number Oxide Content Serial number Oxide Content 1 Al (Aluminum) 264.56 mg / kg 9 Cr (Chromium) 8.00 mg / kg 2 Fe (Iron) 258.80 mg / kg 10 Cu (Copper) 0.83 mg / kg 3 Ca (Calcium) 6555.18 mg / kg 11 Li (Lithium) 22.69 mg / kg 4 Mg (Magnesium) 1564.43 mg / kg 12 Mn (Manganese) 19.39 mg / kg 5 K (Potassium) 58.36 mg / kg 13 Ni (Nickel) 4.05 mg / kg 6 Na (Sodium) 148.38 mg / kg 14 B (Boron) 8.30 mg / kg 7 Ti (Titanium) 13.80 mg / kg 15 Pb (Lead) 0.82 mg / kg 8 Co (Cobalt) 0.52 mg / kg 16 <![CDATA[SiO2 (Silicon Dioxide)]]> 98.157％

[0112] Example 1

[0113] This example provides a method for preparing high - purity quartz sand, and the method for preparing high - purity quartz sand includes the following steps:

[0114] (1) Crush the original quartz ore to a particle size of less than 10 cm, and successively carry out water washing, drying and grinding to obtain quartz sand with a particle size of 80 - 120 mesh; place the quartz sand with a particle size of 80 - 120 mesh in an energy - gathering electrode device, focus the energy through an external power supply, and carry out energy - gathering electrode blasting (5000 V, 30 s) on the tip of the energy - gathering electrode provided in Preparation Example 1 to generate a penetration and impact effect, so that the impurities in the quartz sand are separated from the quartz matrix to obtain a mixed powder containing initially purified quartz sand and impurities; after discharging the separated impurities through the impurity channel in the energy - gathering electrode device, collect the initially purified quartz sand;

[0115] (2) Dissolve 268 g of vitamin C in 1 L of ultrapure water to obtain an electrolyte solution of 268 g / L; mix the preliminarily purified quartz sand and the above electrolyte solution in a mass ratio of 1:5, react in a polytetrafluoroethylene reaction kettle, and at the same time use the poly-energy electrode provided in Preparation Example 1 to perform abrasive washing treatment to strip the surface impurities of the quartz sand to obtain a mixed solution;

[0116] Among them, the abrasive washing treatment is specifically as follows: Generate a poly-energy high-voltage energy of 500 V in the poly-energy electrode to form a vortex in the solution, so as to perform abrasive washing treatment on the quartz sand; the abrasive washing treatment is carried out under stirring, the rotation speed of the stirring is 200 rpm, the temperature of the stirring is 80 °C, and the time of the stirring is 2 h; filter the mixed solution after the abrasive washing treatment, and separate to obtain an electrolyte solution and quartz sand solid; wash the quartz sand solid with pure water until neutral, and then dehydrate and dry to obtain the high-purity quartz sand.

[0117] Example 2

[0118] This example provides a method for preparing high-purity quartz sand, and the method for preparing high-purity quartz sand includes the following steps:

[0119] (1) Crush the original quartz ore to a particle size of less than 10 cm, and successively carry out water washing, drying and grinding to obtain quartz sand with a particle size of 100-140 mesh; place the quartz sand with a particle size of 100-140 mesh in a poly-energy electrode device, focus energy through an external power supply, and generate a penetration and impact effect at the tip of the poly-energy electrode provided in Preparation Example 1 to perform poly-energy electrode blasting (4000 V, 20 s), so that the impurities in the quartz sand are separated from the quartz matrix to obtain a mixed powder containing preliminarily purified quartz sand and impurities; after discharging the separated impurities through the impurity channel in the poly-energy electrode device, collect the preliminarily purified quartz sand;

[0120] (2) Dissolve 268 g of ferrous sulfate in 1 L of ultrapure water to obtain an electrolyte solution of 268 g / L; mix the preliminarily purified quartz sand and the above electrolyte solution in a mass ratio of 1:5, react in a polytetrafluoroethylene reaction kettle, and at the same time use the poly-energy electrode provided in Preparation Example 1 to perform abrasive washing treatment to strip the surface impurities of the quartz sand to obtain a mixed solution;

[0121] Among them, the abrasive washing treatment is specifically as follows: Generate a poly-energy high-voltage energy of 400 V in the poly-energy electrode to form a vortex in the solution, so as to perform abrasive washing treatment on the quartz sand; the abrasive washing treatment is carried out under stirring, the rotation speed of the stirring is 200 rpm, the temperature of the stirring is 80 °C, and the time of the stirring is 2 h; filter the mixed solution after the abrasive washing treatment, and separate to obtain an electrolyte solution and quartz sand solid; wash the quartz sand solid with pure water until neutral, and then dehydrate and dry to obtain the high-purity quartz sand.

[0122] Example 3

[0123] This example provides a method for preparing high-purity quartz sand. The method for preparing high-purity quartz sand includes the following steps:

[0124] (1) The original quartz ore is crushed to a particle size of less than 10 cm, and then washed, dried, and ground in sequence to obtain quartz sand with a particle size of 140-180 mesh. The quartz sand with a particle size of 140-180 mesh is placed in a polyenergy electrode device, and the energy is focused through an external power supply to generate a penetration and impact effect at the tip of the polyenergy electrode provided in Example 1 for polyenergy electrode blasting (6000 V, 50 s), so that the impurities in the quartz sand are separated from the quartz matrix to obtain a mixed powder containing initially purified quartz sand and impurities. After discharging the separated impurities through the impurity channel in the polyenergy electrode device, the initially purified quartz sand is collected;

[0125] (2) 268 g of magnesium chloride is dissolved in 1 L of ultrapure water to obtain an electrolyte solution with a concentration of 268 g / L. The initially purified quartz sand and the above electrolyte solution are mixed in a mass ratio of 1:5 and reacted in a polytetrafluoroethylene reaction kettle. At the same time, the polyenergy electrode provided in Preparation Example 1 is used for grinding and washing treatment to strip the surface impurities of the quartz sand to obtain a mixed solution. Among them, the grinding and washing treatment is specifically as follows: a polyenergy high voltage energy of 600 V is generated by the polyenergy electrode to form a vortex in the solution, so as to perform grinding and washing treatment on the quartz sand. The grinding and washing treatment is carried out under stirring, the rotation speed of the stirring is 200 rpm, the temperature of the stirring is 80 °C, and the time of the stirring is 2 h. The mixed solution after the grinding and washing treatment is filtered to separate the electrolyte solution and the quartz sand solid. After the quartz sand solid is washed with pure water to neutrality, it is dehydrated and dried to obtain the high-purity quartz sand.

[0126] Example 4

[0127] This example provides a method for preparing high-purity quartz sand. The difference from Example 1 is only that the polyenergy electrode provided in Preparation Example 1 in step (1) is replaced with the polyenergy electrode provided in Preparation Example 2, and other steps are exactly the same as those in Example 1.

[0128] Example 5

[0129] This example provides a method for preparing high-purity quartz sand. The difference from Example 1 is only that the polyenergy electrode provided in Preparation Example 1 in step (1) is replaced with the polyenergy electrode provided in Preparation Example 3, and other steps are exactly the same as those in Example 1.

[0130] Example 6

[0131] This embodiment provides a method for preparing high-purity quartz sand. The difference from Embodiment 1 is that in step (1), the energy of the polyenergy electrode is 2000V, and the blasting time of the polyenergy electrode is 10 min. Other steps are the same as those in Embodiment 1.

[0132] Embodiment 7

[0133] This embodiment provides a method for preparing high-purity quartz sand. The difference from Embodiment 1 is that in step (2), the energy of the polyenergy electrode is 10 kV, and the blasting time of the polyenergy electrode is 5 s. Other steps are the same as those in Embodiment 1.

[0134] Embodiment 8

[0135] This embodiment provides a method for preparing high-purity quartz sand. The difference from Embodiment 1 is only that in step (2), the concentration of the electrolyte solution is 260 g / L. Other steps are exactly the same as those in Embodiment 1.

[0136] Embodiment 9

[0137] This embodiment provides a method for preparing high-purity quartz sand. The difference from Embodiment 1 is only that in step (2), the concentration of the electrolyte solution is 280 g / L. Other steps are exactly the same as those in Embodiment 1.

[0138] Embodiment 10

[0139] This embodiment provides a method for preparing high-purity quartz sand. The difference from Embodiment 1 is only that in step (2), the rotation speed of the stirring is 100 rpm, the temperature of the stirring is 85 °C, and the time of the stirring is 3 h. Other steps are exactly the same as those in Embodiment 1.

[0140] Embodiment 11

[0141] This embodiment provides a method for preparing high-purity quartz sand. The difference from Embodiment 1 is only that in step (2), the rotation speed of the stirring is 300 rpm, the temperature of the stirring is 75 °C, and the time of the stirring is 1 h. Other steps are exactly the same as those in Embodiment 1.

[0142] Comparative Example 1

[0143] This comparative example provides a method for preparing high-purity quartz sand. The method for preparing high-purity quartz sand includes the following steps:

[0144] The raw quartz ore is crushed to a particle size of less than 10 cm, and then washed, dried, and ground in sequence to obtain quartz sand with a particle size of 80-120 mesh; 268 g of vitamin C is dissolved in 1 L of ultrapure water to obtain an electrolyte solution with a concentration of 268 g / L; the quartz sand with a particle size of 80-120 mesh and the above electrolyte solution are mixed in a mass ratio of 1:5, and the reaction is carried out in a polytetrafluoroethylene reaction kettle. At the same time, the polyenergy electrode provided in Preparation Example 1 is used for grinding and washing treatment to strip the surface impurities of the quartz sand and obtain a mixed solution;

[0145] Among them, the grinding and washing treatment is specifically as follows: a polyenergy high-voltage energy of 500 V is generated by the polyenergy electrode to form a vortex in the solution, so as to carry out the grinding and washing treatment on the quartz sand; the grinding and washing treatment is carried out under stirring, the rotation speed of the stirring is 200 rpm, the temperature of the stirring is 80 °C, and the time of the stirring is 2 h; the mixed solution after the grinding and washing treatment is filtered to separate the electrolyte solution and the quartz sand solid; after the quartz sand solid is washed with pure water to neutrality, it is dehydrated and dried to obtain the high-purity quartz sand.

[0146] Comparative Example 2

[0147] This comparative example provides a method for purifying quartz sand. The difference from Example 1 is only that the electrolyte solution provided in step (2) is replaced with pure water of equal mass, and the other steps are exactly the same as those in Example 1.

[0148] Comparative Example 3

[0149] This comparative example provides a method for purifying quartz sand. The difference from Example 1 is only that in step (2), the grinding and washing treatment is no longer carried out using the polyenergy electrode, but instead: the grinding and washing treatment is carried out by ball milling, the grinding medium is zirconia balls, the mass ratio of the quartz sand to be decontaminated and the zirconia balls is 1:4, and the rotation speed of the ball milling is 200 rpm, the temperature of the ball milling is 80 °C, and the time of the ball milling is 5 h; the other steps are exactly the same as those in Example 1.

[0150] Test Example 2

[0151] Identification of high-purity quartz sand components

[0152] Test samples: high-purity quartz sand provided in Examples 1-11, high-purity quartz sand provided in Comparative Examples 1-4.

[0153] The test results are shown in Tables 3-5 below:

[0154] Table 3

[0155]

[0156]

[0157] Table 4

[0158] Serial number Oxide Example 6 Example 7 Example 8 Example 9 Example 10 1 Al (Aluminum) (mg / kg) 3.35 3.65 5.12 2.34 4.28 2 Fe (Iron) (mg / kg) 3.06 3.14 4.84 2.05 3.99 3 Ca (Calcium) (mg / kg) 0.15 0.23 0.31 0.15 0.28 4 Mg (Magnesium) (mg / kg) 0.19 0.24 0.52 0.19 0.49 5 K (Potassium) (mg / kg) 0.55 0.61 0.70 0.52 0.66 6 Na (Sodium) (mg / kg) 2.52 2.53 2.42 2.12 2.38 7 Ti (Titanium) (mg / kg) 0.12 0.11 0.10 0.10 0.11 8 Co (Cobalt) (mg / kg) 0.05 0.04 0.06 0.05 0.06 9 Cr (Chromium) (mg / kg) 0.15 0.16 0.17 0.09 0.18 10 Cu (Copper) (mg / kg) 0.05 0.07 0.08 0.02 0.07 11 Li (Lithium) (mg / kg) 0.15 0.20 0.21 0.11 0.20 12 Mn (Manganese) (mg / kg) 0.25 0.24 0.25 0.22 0.22 13 Ni (Nickel) (mg / kg) 0.50 0.52 0.49 0.05 0.52 14 B (Boron) (mg / kg) 0.75 0.80 0.85 0.20 0.76 15 Pb (Lead) (mg / kg) 0.05 0.04 0.05 0.03 0.04 16 <![CDATA[SiO2 (Silicon Dioxide) (%)]]> 99.9987 99.9986 99.9982 99.9991 99.9984

[0159] Table 5

[0160]

[0161]

[0162] As can be seen from the data in Table 3 to Table 5, the present invention focuses energy through an external power supply, generates a penetration and impact effect at the tip of the electrode for the blasting of the energy-gathering electrode, separates the impurities in the quartz sand from the quartz matrix, and preferentially destroys the binding force of the impurities in view of the physical property differences between the conductive impurities and quartz. On the basis of avoiding damage to the quartz matrix, the impurities in the lattice of the quartz sand are removed to obtain initially purified quartz sand. The present invention combines the physical abrasion and washing of the energy-gathering electrode with the chemical reaction of the electrolyte solution for the initially purified quartz sand, and the two cooperate synergistically to achieve the non-corrosive and highly efficient stripping of the surface adhered impurities on the surface of the quartz sand, thereby obtaining high-purity quartz sand, the purity of which can reach 5N or above, that is, the purity of the finally obtained high-purity quartz sand is above 99.9990%.

[0163] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing high-purity quartz sand, characterized in that: The preparation method comprises the following steps: The quartz sand is placed in an energy-gathering electrode device, and energy is focused by an external power source, so that penetration and impact are generated at the tip of the energy-gathering electrode to perform energy-gathering electrode blasting, so that impurities in the quartz sand are separated from the quartz matrix, and initially purified quartz sand is obtained; The pre-purified quartz sand is mixed with an electrolyte solution, and is subjected to a grinding and washing treatment using an energy-focusing electrode, so that impurities adhering to the surface of the pre-purified quartz sand are separated from the quartz matrix to obtain high-purity quartz sand.

2. The method for preparing high-purity quartz sand according to claim 1, characterized in that: The impurities include any one of aluminum oxide, iron oxide, titanium dioxide, calcium oxide, magnesium oxide, potassium oxide or sodium oxide, or a combination of at least two thereof.

3. The method for preparing high-purity quartz sand according to claim 1, characterized in that: The energy-gathering electrode is obtained by calcining lanthanum oxide, vanadium oxide and tungsten oxide; Preferably, the mass ratio of lanthanum oxide, vanadium oxide and tungsten oxide is (0.1-2):(0.1-2):(7-9); Preferably, the preparation method of the energy-gathering electrode comprises: mixing lanthanum oxide, vanadium oxide and tungsten oxide, placing the mixture in a mold, and calcining the mixture to obtain the energy-gathering electrode; Preferably, the calcination temperature is 2000-2200° C., and the calcination time is 6-18 hours.

4. The method for preparing high-purity quartz sand according to claim 1, characterized in that: The quartz sand needs to be pre-treated as follows before the energy-gathering electrode blasting: The quartz ore is crushed to a particle size of less than 10 cm, and then washed, dried and ground in sequence to obtain quartz sand with a particle size of 60 to 180 mesh.

5. The method for purifying quartz sand by using energy-gathering electrode blasting according to claim 1, characterized in that: During the blasting process of the energy-gathering electrode, the quartz undergoes a crystal transformation, and the crystal transformation of the quartz is from α-quartz to β-quartz; Preferably, the energy of the energy-gathering electrode during blasting is 3000-8000V, and the blasting time of the energy-gathering electrode is 10-60s.

6. The method for purifying quartz sand by using energy-gathering electrode blasting according to claim 1, characterized in that: After the energy electrode is blasted, the following post-processing is required: After the separated impurities are discharged through the impurity channel in the energy-gathering electrode device, the preliminarily purified quartz sand is collected.

7. The method for purifying quartz sand by using energy-gathering electrode blasting according to claim 1, characterized in that: The mass ratio of the initially purified quartz sand to the electrolyte solution is 1:(3-8); Preferably, the concentration of the electrolyte solution is 200-300 g / L; Preferably, the solute in the electrolyte solution is selected from any one or a combination of at least two of magnesium chloride, ferrous sulfate or vitamin C; Preferably, the solvent in the electrolyte solution is selected from distilled water and / or ultrapure water.

8. The method for purifying quartz sand by using energy-gathering electrode blasting according to claim 1, characterized in that: The grinding and washing treatment specifically includes: the high-pressure energy generated by the energy-gathering electrode forms a vortex in the solution, thereby grinding and washing the quartz sand; Preferably, the energy of the energy focusing electrode is 300-800V.

9. The method for purifying quartz sand by using energy-gathering electrode blasting according to claim 1 or 8, characterized in that: The scrubbing treatment is carried out under stirring, and the stirring speed is 100 to 500 rpm; Preferably, the temperature of the scrubbing treatment is 70-90°C; Preferably, the scrubbing treatment time is 0.5 to 5 hours; Preferably, the grinding and washing treatment is carried out in a polytetrafluoroethylene reaction tank.

10. The method for purifying quartz sand by using energy-gathering electrode blasting according to claim 1, characterized in that: The scrubbing treatment also includes the following purification steps: The mixed solution after grinding and washing is filtered to separate the electrolyte solution and the quartz sand solid; the quartz sand solid is washed to neutrality and then dried to obtain the high-purity quartz sand; Preferably, the removal rate of impurities is above 99.5%; Preferably, the purity of the high-purity quartz sand is above 99.9990% based on silicon dioxide.

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