Microwave-conductance assisted flotation method and application thereof in quartz sand purification

Abstract

The invention discloses a microwave-conductance-assisted flotation method and application of the microwave-conductance-assisted flotation method in quartz sand purification. The microwave-conductance auxiliary flotation method comprises the steps that the negative electrode plate and the positive electrode plate are partially or completely immersed into quartz sand ore pulp in a flotation machine and kept electrified, then a flotation reagent is added into the quartz sand ore pulp under stirring, microwaves are started, the microwaves are closed after operation is conducted for a period of time, the negative electrode plate and the positive electrode plate are powered off and taken out, stirring is kept, air blowing is conducted, and flotation is conducted. The purpose of deeply purifying the alkali metal impurities in the quartz sand is achieved by combining microwaves, electric conductance and flotation processes, especially flotation reagents.

Description

Technical Field

[0001] The present invention relates to the technical field of quartz sand treatment, and particularly relates to a microwave-conductance assisted flotation method and its application in quartz sand purification. Background Art

[0002] As a key basic material in many high-end fields, the purity of high-purity quartz sand directly determines the performance and quality of products. From semiconductor chip manufacturing to optical communication industries, from solar photovoltaic fields to high-end optical instrument production, high-purity quartz sand plays an indispensable role. Alkali metal impurities (such as Li, Na, K, etc.), as an important index to measure the quality of high-purity quartz sand, have a significant impact on the performance and application of high-purity quartz sand: at high temperatures, alkali metals will cause a decrease in the thermal stability and melting point of quartz sand and its products, damage to optoelectronic properties, and a decrease in chemical stability, etc. Especially in the semiconductor industry, there are extremely high requirements for the content of alkali metal elements in high-purity quartz sand and its products.

[0003] With the improvement of semiconductor technology requirements, the requirements for the quality of high-purity quartz sand are also continuously increasing. Whether it is semiconductor-grade high-purity quartz sand or the inner layer sand of photovoltaic crucibles, it is necessary to avoid high dependence on imports and achieve independent guarantee of raw ore resources. Therefore, developing more efficient high-purity quartz sand purification processes and carrying out in-depth technological upgrades are of great significance for breaking technological monopolies.

[0004] Flotation is a beneficiation method that utilizes the differences in the physicochemical properties of mineral surfaces to perform selective separation at the gas-liquid-solid three-phase interface. Its core is to bring the target mineral particles to the surface of the pulp through bubbles, thereby realizing the separation of useful minerals and gangue minerals.

[0005] In the high-purity quartz sand purification process, flotation has become an indispensable important link due to its characteristics such as efficient resource utilization, refined separation, adaptability to complex ores, adjustable adsorption capacity, and easy operation.

[0006] Traditional flotation processes rely on stirring to increase the contact between reagent molecules and the mineral surface. However, the reagents used in the flotation process are often surfactants with hydrophobic long chains. Due to their certain hydrophobicity, simply through stirring, the reagents cannot make full contact with the mineral surface, which in turn leads to a decrease in reagent utilization rate and affects flotation efficiency, etc. Especially in the field of high-purity quartz sand purification, due to higher requirements for the removal rate of impurities, the traditional stirring flotation process cannot meet the actual needs, and it is necessary to develop other means-assisted flotation processes to improve the purification efficiency of quartz sand.

[0007] After retrieval, there are the following existing technologies: 1) Removing alkali metal impurities by means of high-temperature chlorination (the current main process).

[0008] The patent specification with the publication number CN108910897A discloses a method for high-temperature activation and purification of quartz sand. By reacting quartz sand with chlorine gas for 15 - 120 minutes while swinging around an axis in a sealed furnace at 950 - 1450 °C, the impurity elements of alkali metals and alkaline earth metals in the quartz sand are removed.

[0009] The patent specification with the publication number CN117985725A discloses a treatment method for suspension chlorination roasting and purification of quartz sand. Through preheating and multi-stage suspension roasting, the heating, chlorination reaction, and cooling of quartz sand are carried out in stages, and the products of each stage are controllable and adjustable, so as to remove impurities such as alkali metals and alkaline earth metals on the surface of quartz sand as much as possible to improve the purity of quartz sand.

[0010] 2) Use other methods to remove alkali metal impurities.

[0011] The patent specification with the publication number CN115321544A discloses an ultrasonic oscillation - electro-adsorption cleaning method and purification process for high-purity quartz sand. It uses ultrasonic oscillation to assist in separating metal ions and charged particles on the surface of quartz sand. At the same time, through electro-adsorption technology, metal ions, charged particles, etc. in the solution are adsorbed onto the electrodes on both sides, so as to achieve the purpose of efficiently removing the attached impurities on the surface of high-purity quartz sand, and solve the problem that it is difficult to improve the purity of quartz sand due to impurity residues in the existing quartz sand purification process.

[0012] The patent specification with the publication number CN117819556A discloses a method for preparing high-purity quartz assisted by high-alkalinity activation. First, calcination and water quenching are used to cause cracks in the quartz sand and open the channels of the quartz sand. Then, high-strength alkali is used to activate the quartz sand to destroy the crystal lattice structure of the quartz, making the impurities in the crystal lattice become free states that are easy to remove. Then, combined with high-temperature acid leaching, the exposed lattice impurities are removed to achieve the purpose of removing impurity elements, especially the alkali metal sodium element.

[0013] The patent specification with the publication number CN119019089A discloses a method for preparing low-hydroxyl and low-alkali-metal high-purity quartz sand, which includes crushing and sand making, using hydrofluoric acid (HF) as a pH adjuster and activator, and using dodecylamine as a collector for flotation; then using a composite acid solution composed of HF and ferrate for oxidative acid washing and impurity removal; after oxidative acid washing and impurity removal, the quartz raw material is mixed with carbon powder and calcined at a high temperature of 1100 - 1350 °C; using a composite acid solution composed of halogen acid and heavy metal complexing agent to carry out acid washing and impurity removal on the obtained quartz raw material, and after acid washing, washing with water and drying to obtain low-hydroxyl and low-alkali-metal high-purity quartz sand.

[0014] Existing processes for removing alkali metal impurities often require the use of high-risk gases such as hydrogen chloride, chlorine and other chlorides in high-temperature chlorination or the use of strong alkalis or strong acids (such as hydrofluoric acid) for auxiliary purification. Since these are all high-risk chemicals, their storage and transportation have strict requirements. In long-term use, they will not only corrode equipment but also pose a safety risk of leakage and injury to personnel, and further increase the production cost of enterprises.

[0015] The method of removing impurities by simply adsorbing metal ions, charged particles, etc. in the solution onto the electrodes on both sides through electroadsorption technology has limited impurity removal effect. Due to the poor conductivity of quartz sand, its migration in water relying on its electric property is often only applicable to free metal impurities or metal impurities that are easily peeled off on the surface of quartz, and it is impossible to deeply remove alkali metal impurities. Summary of the Invention

[0016] In view of the above technical problems and deficiencies in the art, the present invention provides a microwave-conductivity assisted flotation method and its application, which can avoid using high temperature and high-risk chemical reagents while meeting the condition of deeply removing alkali metal impurities from quartz sand. See Figure 1 , and the specific measures include: By using the method of microwave-assisted flotation, the microwave is used to increase the rapid movement of the reagent in water, thereby increasing its water solubility and making the pulp system more uniform. At the same time, it also increases the contact opportunity between the reagent molecules and the alkali metal impurities in the mineral, improving the flotation efficiency; By using the method of conductivity-assisted flotation, the alkali metal impurities inside the quartz sand after pretreatment such as roasting are easily lose electrons under the influence of an external current / electric field and perform charge transfer along the microcracks or the surface of the quartz, and then different positive and negative charge regions appear on the surface of the quartz; under the assistance of microwave, the reagent molecules are adsorbed on the new charge regions on the surface of the quartz through electrostatic action, thereby achieving the purpose of deep purification.

[0017] The specific technical solution is as follows: In the first aspect, the present invention provides a microwave-conductivity assisted flotation method, including: partially or completely immersing the cathode and anode electrode plates in the quartz sand pulp in the flotation machine and keeping them energized, then adding a flotation reagent to the quartz sand pulp under stirring and turning on the microwave. After running for a period of time, turn off the microwave, cut off the power supply of the cathode and anode electrode plates and take them out, keep stirring, and inflate for flotation.

[0018] Preferably, in the microwave-conductivity assisted flotation method, the rotation speed of the stirring is 1500-2000 r / min.

[0019] Preferably, in the microwave-conductivity assisted flotation method, the frequency of the microwave is 2-2.45 GHz.

[0020] Preferably, in the microwave-conductivity assisted flotation method, direct current is applied to the cathode and anode plates. More preferably, the direct current voltage is 100 - 220 V.

[0021] Preferably, in the microwave-conductivity assisted flotation method, the operation time is 15 - 35 minutes, such as 20 minutes, 25 minutes, 30 minutes, etc.

[0022] Preferably, the microwave-conductivity assisted flotation method is reverse flotation.

[0023] Preferably, in the microwave-conductivity assisted flotation method, the flotation reagents include at least one of cationic collectors and chelating agents.

[0024] Further, the cationic collector may include one or more of dodecylamine, hexadecylamine, octadecylamine, etc.

[0025] Further, based on the mass of quartz sand in the quartz sand pulp, the addition amount of the cationic collector is 20 - 25 g / 500 kg.

[0026] Further, the chelating agent may include crown ether compounds. More specifically, the crown ether compounds may include one or more of 18-crown-6, 15-crown-5, 12-crown-4, etc. For alkali metal impurities, the present invention particularly uses crown ether compound chelating agents.

[0027] Further, based on the mass of quartz sand in the quartz sand pulp, the addition amount of the chelating agent is 40 - 50 g / 500 kg.

[0028] In a second aspect, the present invention provides an application of the microwave-conductivity assisted flotation method described in the first aspect in the purification of quartz sand. The microwave-conductivity assisted flotation method can be used for the purification of high-purity quartz sand (with a silicon dioxide content of more than 99.999 wt%). The microwave-conductivity assisted flotation method can be used to separate at least alkali metal impurities in quartz sand. The alkali metal impurities may include one or more of lithium, sodium, potassium, etc.

[0029] In a third aspect, the present invention provides a purification process for high-purity quartz sand, including the steps: S01: Crushing the ore; S02: Color sorting; S03: Roasting and water quenching; S04: Magnetic separation; S05: First flotation; S06: Acid leaching; S07: Performing a second flotation using the microwave-conductivity assisted flotation method described in the first aspect to obtain high-purity quartz sand.

[0030] Preferably, in step S01, the particle size of the crushed ore is 1-3 cm.

[0031] Preferably, in step S02, a color sorter is used to remove the colored ore impurities after crushing through a laser light source.

[0032] Preferably, in step S03, the roasting temperature is 600-800 °C, the roasting time is 2-4 hours, and after water quenching, it is made into sand with a particle size of 60-180 mesh.

[0033] Preferably, in step S04, an electromagnetic separator is used, and the background magnetic field intensity of the electromagnetic separator is 5000-6000 GS, and the magnetic separation time is 2-4 h.

[0034] Preferably, in step S05, sulfuric acid is used as the pH regulator for the first flotation, dodecylamine and sodium dodecyl sulfonate are used as collectors, and the pH of the first flotation is 2-3.

[0035] Preferably, in step S06, the acid used for acid leaching is a mixture of sulfuric acid, hydrochloric acid, and hydrofluoric acid, the acid leaching temperature is 80-100 °C, and the acid leaching time is 6-8 h.

[0036] In step S07, the obtained high-purity quartz sand has a SiO2 mass content of more than 99.999% and an alkali metal impurity mass content of less than 1 ppm.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Deep removal of alkali metal impurities: Microwave-assisted, the microwave action accelerates the molecular movement of the reagent molecules in the pulp, making them more evenly distributed in the system and improving the flotation efficiency; Conductance-assisted, by applying a stable current / electric field, the alkali metal impurities inside the quartz sand undergo charge migration, and then more charge regions are exposed on the quartz surface, which is beneficial to the interaction with the reagent. The combination of microwave, conductance and the flotation process, especially the flotation reagent, achieves the purpose of deeply purifying the alkali metal impurities in the quartz sand.

[0038] 2. The flotation purification process is green and environmentally friendly: Compared with the traditional process for deep removal of alkali metal impurities, this combined process does not use highly hazardous chemicals or strong acids and bases, avoiding equipment corrosion, environmental pollution and potential safety threats to personnel, reducing the enterprise operation cost and improving the enterprise efficiency.

[0039] 3. The purification process of the high-purity quartz sand of the present invention can obtain a high-purity quartz sand product with a silicon dioxide (SiO2) content of more than 99.999 wt% after the second flotation, without the need for high-temperature chlorination and other operations. Brief Description of the Drawings

[0040] Figure 1Schematic diagram of the working principle of the microwave-conductivity assisted flotation method of the present invention.

[0041] Figure 2 Graph showing the test results of the comprehensive mineral analysis data of quartz sand TIMA (Tescan Integrated Mineral Analyzer) before and after microwave-conductivity assisted flotation in Example 1.

[0042] Figure 3 Graph showing the test results of the comprehensive mineral analysis data of quartz sand TIMA before and after microwave-conductivity assisted flotation in Example 2.

[0043] Figure 4 Graph showing the test results of the comprehensive mineral analysis data of quartz sand TIMA before and after microwave-conductivity assisted flotation in Example 3.

[0044] Figure 5 Graph showing the test results of the comprehensive mineral analysis data of quartz sand TIMA after microwave assisted flotation in Comparative Example 1. Detailed implementation manners

[0045] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. The operating methods without specific conditions noted in the following embodiments are generally in accordance with conventional conditions or in accordance with the conditions recommended by the manufacturer.

[0046] Example 1:

[0047] Analysis of the original ore material: Taking a batch of ore from a granitic pegmatite in a certain area of India as an example for material analysis, the mass content of quartz in the original ore is 57.88%, the mass content of feldspar is 21.79%, the mass content of mica is 18.44%, the mass content of hematite / magnetite is 1.29%, and the mass content of the remaining impurity minerals such as rutile and ilmenite is less than 1%.

[0048] Pretreatment process: Use a crusher to roughly crush the raw ore to obtain roughly crushed ore with an average particle size of 1 - 3 cm. The ore with a particle size greater than 3 cm after rough crushing is returned to the crusher for continued crushing; conduct color sorting on the roughly crushed ore with an average particle size of 1 - 3 cm. The color sorter uses a laser light source to remove the roughly crushed ore with more colored impurities; conduct high-temperature roasting and water quenching on the screened roughly crushed ore. The heating temperature is 600 °C and the time is 2 hours. After water quenching, it is finely crushed and made into quartz sand particles of 60 - 180 mesh; use an electromagnetic separator to conduct magnetic separation on the obtained quartz sand particles. The background magnetic field intensity of the electromagnetic separator is 6000 GS, and the magnetic separation time is 2 h to separate magnetic mineral impurities; conduct flotation on the magnetically separated quartz sand. Use sulfuric acid as an adjusting agent to adjust the pH = 2, and successively add dodecylamine 40 g / t (t represents ton, based on the mass of quartz sand in the pulp, the same below) and sodium dodecyl sulfonate 40 g / t for flotation. After flotation, rinse with clean water three times and dry; conduct acid leaching on the dried quartz sand. The acid leaching solution is a mixture of sulfuric acid, hydrochloric acid, and hydrofluoric acid with a volume ratio of 1:1:1, and the dosage is 1000 L / t. The acid leaching temperature is 80 °C and the acid leaching time is 6 h. After acid leaching, rinse the quartz sand with clean water three times, centrifuge, and dry for standby.

[0049] Microwave-conductivity assisted flotation process: Adopt the reverse flotation process. Pour 500 kg of dried quartz sand into the flotation machine, add water to form pulp and control the water level in the flotation machine; extend the cathode and anode plates below the liquid surface and start energizing. The DC voltage is 100 V, and start the stirrer with a rotation speed of 2000 r / min; after 20 minutes, add the cationic collector dodecylamine to the pulp with a dosage of 20 g, and at the same time start the microwave emitter with a frequency of 2.45 GHz; after 10 minutes, add the crown ether chelating agent 18-crown-6 with a dosage of 40 g. After stirring for 20 minutes, turn off the microwave emitter and end the power supply, take out the cathode and anode plates, start aeration and start flotation. The flotation foam flows out from the flotation cell along with the water level. After 20 minutes of flotation, it is completed. Rinse with clean water three times and dry the quartz sand as the final finished sand.

[0050] The test results show that for the quartz sand treated according to the above process parameters and conditions, its main content indicators are shown in Table 1 below. Among them, the mass content of SiO2 (%) is obtained by X-ray fluorescence spectrometry (XRF), and the content of alkali metal elements (ppm, one millionth of the mass, the same below) is obtained by inductively coupled plasma optical emission spectrometry (ICP-OES). The quartz sand before microwave-conductivity assisted flotation is the quartz sand after acid leaching, rinsed with clean water and dried, and the quartz sand after microwave-conductivity assisted flotation is the final finished sand, which will not be elaborated below.

[0051] Table 1

[0052] The test results of the TIMA comprehensive mineral analysis data of quartz sand before and after microwave-conductivity assisted flotation are as follows Figure 2 shown

[0053] After comparing the above data, it is found that microwave-conductivity assisted flotation can deeply remove the alkali metal impurity minerals mixed in quartz sand. After one treatment, the alkali metal impurity content is less than 1 ppm, and the SiO2 content reaches more than 99.999%. It not only efficiently removes the impurities on the surface of quartz sand, but also has an obvious effect on the alkali metal impurities inside the quartz sand. The processed quartz sand finished product can be used for the inner layer sand of crucibles and semiconductor-grade quartz products

[0054] Example 2

[0055] The analysis and pretreatment process of the original ore materials are the same as those in Example 1, that is, the quartz sand obtained by pretreating the same batch of original ore as in Example 1 is used

[0056] Microwave-conductivity assisted flotation process: The difference from the microwave-conductivity assisted flotation process in Example 1 is only that the cationic collector is hexadecylamine and the crown ether chelating agent is 15-crown-5, and the rest are the same, and the finished sand is obtained

[0057] The test results show that for the quartz sand treated according to the above process parameters and conditions, the main content indexes are as shown in Table 2 below

[0058] Table 2

[0059] The test results of the TIMA comprehensive mineral analysis data of quartz sand before and after microwave-conductivity assisted flotation are as follows Figure 3 shown

[0060] After comparing the above data, it is found that when hexadecylamine is selected as the cationic collector and 15-crown-5 is used as the chelating agent for flotation, combined with microwave-conductivity assistance, the alkali metal impurity minerals mixed in quartz sand can be deeply removed. After one treatment, the alkali metal impurity content is less than 1 ppm, and the SiO2 content reaches more than 99.999%

[0061] Example 3

[0062] The analysis and pretreatment process of the original ore materials are the same as those in Example 1, that is, the quartz sand obtained by pretreating the same batch of original ore as in Example 1 is used

[0063] Microwave-conductivity assisted flotation process: The difference from the microwave-conductivity assisted flotation process in Example 1 is only that the cationic collector is octadecylamine and the crown ether chelating agent is 12-crown-4, and the rest are the same, and the finished sand is obtained

[0064] The test results show that for the quartz sand processed according to the above process parameters and conditions, the main content indicators are as shown in Table 3 below.

[0065] Table 3

[0066] The test results of the TIMA comprehensive mineral analysis data of the quartz sand before and after microwave-conductivity assisted flotation are as Figure 4 shown.

[0067] After comparing the above data, it is found that when octadecylamine is selected as the cationic collector and 12-crown-4 is used as the chelating agent for flotation, combined with microwave-conductivity assistance, the alkali metal impurity minerals mixed in the quartz sand can be deeply removed. After one treatment, the alkali metal impurity content is less than 1 ppm, and the SiO2 content reaches more than 99.999%.

[0068] Comparative Example 1: The analysis and pretreatment process of the original ore materials are the same as those in Example 1, that is, the quartz sand obtained by pretreating the same batch of original ore as in Example 1 is used.

[0069] The difference in the microwave-conductivity assisted flotation process from that in Example 1 is only that there is no conductivity assistance, and the rest are the same.

[0070] The test results show that for the quartz sand processed according to the above process parameters and conditions, the main content indicators are as shown in Table 4 below.

[0071] Table 4

[0072] The test results of the TIMA comprehensive mineral analysis data of the quartz sand after microwave assisted flotation are as Figure 5 shown.

[0073] After comparing the above data, it is found that microwave assisted flotation can efficiently remove the alkali metal impurity minerals mixed outside the quartz sand. After one treatment, the alkali metal impurity content is reduced to about 10 ppm, and the SiO2 content reaches 99.990%. However, it has basically no removal effect on the impurities inside the quartz sand, and the processed finished product cannot meet the requirements of photovoltaic inner layer sand and semiconductor grade quartz products.

[0074] Comparative Example 2: The analysis and pretreatment process of the original ore materials are the same as those in Example 1, that is, the quartz sand obtained by pretreating the same batch of original ore as in Example 1 is used.

[0075] The difference in the microwave-conductivity assisted flotation process from that in Example 1 is only that there is no microwave assistance, and the rest are the same.

[0076] The test results show that for the quartz sand treated according to the above process parameters and conditions, the main content indexes are as shown in Table 5 below.

[0077] Table 5

[0078] After comparing the above data, it is found that electroconductivity-assisted flotation can remove some alkali metal impurity minerals to a certain extent. After one treatment, the alkali metal impurity content is reduced to about 30 ppm, and the SiO2 content reaches 99.982%. However, the removal efficiency of alkali metal impurities is low, and the processed finished product cannot meet the requirements of photovoltaic inner layer sand and semiconductor-grade quartz products.

[0079] In summary, the present invention can deeply remove alkali metal impurities. It can not only remove the alkali metal impurities on the surface of quartz, but also has an obvious effect on removing the alkali metal impurities inside quartz. Moreover, the flotation combined process is green and environmentally friendly, without using high-risk chemicals.

[0080] In addition, it should be understood that after reading the above description of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

Claims

1. A microwave-conductivity assisted flotation method, characterized in that, Including: Partially or completely immerse the cathode and anode electrode plates in the quartz sand pulp in the flotation machine and keep them energized. Then, add flotation reagents to the quartz sand pulp under stirring and turn on the microwave. After running for a period of time, turn off the microwave, cut off the power supply of the cathode and anode electrode plates and take them out. Keep stirring and aerate for flotation.

2. The microwave-conductivity assisted flotation method according to claim 1, wherein The rotation speed of the stirring is 1500 - 2000 r / min; The frequency of the microwave is 2 - 2.45 GHz.

3. The microwave-conductivity assisted flotation method according to claim 1, characterized in that, The cathode and anode electrode plates are connected with direct current, and the direct current voltage is 100 - 220 V.

4. The microwave-conductivity assisted flotation method according to claim 1, characterized in that The running time is 15 - 35 minutes.

5. The microwave-conductivity assisted flotation method according to claim 1, wherein The microwave-conductivity assisted flotation method is reverse flotation; The flotation reagents include at least one of cationic collectors and chelating agents; The cationic collector includes one or several of dodecylamine, hexadecylamine, and octadecylamine; Based on the mass of quartz sand in the quartz sand pulp, the addition amount of the cationic collector is 20 - 25 g / 500 kg; The chelating agent includes crown ether compounds; the crown ether compounds include one or several of 18-crown-6, 15-crown-5, and 12-crown-4; Based on the mass of quartz sand in the quartz sand pulp, the addition amount of the chelating agent is 40 - 50 g / 500 kg.

6. Application of the microwave-conductivity assisted flotation method according to any one of claims 1 - 5 in the purification of quartz sand.

7. The application according to claim 6, wherein The microwave-conductivity assisted flotation method is used for the purification of high-purity quartz sand; The microwave-conductivity assisted flotation method is at least used to separate alkali metal impurities in quartz sand.

8. The application according to claim 7, characterized in that, The alkali metal impurities include one or several of lithium, sodium, and potassium.

9. A purification process for high-purity quartz sand, characterized in that, Including steps: S01: Crushing the ore; S02: Color sorting; S03: Roasting and water quenching; S04: Magnetic separation; S05: First flotation; S06: Acid leaching; S07: Conduct the second flotation using the microwave-conductivity assisted flotation method according to any one of claims 1 - 5 to obtain high-purity quartz sand.

10. According to the purification process of high-purity quartz sand described in claim 9, characterized in that In step S01, the particle size of the crushed ore is 1 - 3 cm; In step S02, use a color sorter to remove the colored ore impurities after crushing through a laser light source; In step S03, the roasting temperature is 600 - 800 °C, the roasting time is 2 - 4 hours, and after water quenching, the sand is made into particles of 60 - 180 mesh; In step S04, use an electromagnetic magnetic separator, the background magnetic field intensity of the electromagnetic magnetic separator is 5000 - 6000 GS, and the magnetic separation time is 2 - 4 h; In step S05, sulfuric acid is used as the pH regulator in the first flotation, and dodecylamine and sodium dodecylsulfonate are used as collectors, and the pH of the first flotation is 2 - 3; In step S06, the acid used in the acid leaching is a mixture of sulfuric acid, hydrochloric acid, and hydrofluoric acid, the acid leaching temperature is 80 - 100 °C, and the acid leaching time is 6 - 8 h; In step S07, the mass content of SiO2 in the obtained high-purity quartz sand is above 99.999%, and the mass content of alkali metal impurities is less than 1 ppm.

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