Quartz sand microwave purification device, purification method and high-purity quartz sand

Abstract

The application provides a quartz sand microwave purification device, a purification method and high-purity quartz sand. The device comprises a microwave generating mechanism, a material placing mechanism and a shell. The inner wall of the shell surrounds an ellipsoidal cavity. The upper and lower shells are detachably connected. The upper shell is provided with a gas outlet pipe and a feeding pipe which extend into the ellipsoidal cavity. The lower shell is provided with a material placing mechanism positioning member corresponding to the position of the long semi-axis of the ellipsoidal cavity. The microwave generating mechanism extends into the ellipsoidal cavity from the position of the long semi-axis of the ellipsoidal cavity of the upper shell. The microwave generating position of the microwave generating mechanism is located at the upper focal point of the ellipsoidal cavity. The material placing mechanism comprises a material carrying disc provided with an opening at the bottom and a storage groove connected with the material carrying disc and located below the material carrying disc. The ellipsoidal cavity double focal point structure is matched with the microwave generating position of the microwave generating mechanism, the material carrying disc, the storage groove and other designs to realize microwave-water quenching-acid washing integration, improve the microwave utilization rate and the heating efficiency, improve the purification efficiency, and reduce the energy consumption and the cost.

Description

Technical Field

[0001] This invention relates to the field of quartz sand purification technology, and more specifically, to a microwave purification device, purification method, and high-purity quartz sand. Background Technology

[0002] High-purity quartz sand is a fundamental raw material for high-end manufacturing industries such as photovoltaics, semiconductors, communications, and defense. With the rapid development of these applications, the supply of high-quality, high-purity natural quartz resources is falling short of demand. Deep purification of ordinary, low-grade natural quartz ore has become the mainstream approach to obtaining high-purity quartz sand. However, ordinary natural quartz ore is affected by magma movement and geological conditions, resulting in variations in impurity content and distribution, fluid inclusion types, and chemical elements. The quality of quartz ore varies even between different regions and within the same region. Under a given purification cycle, existing purification technologies yield quartz sand of inconsistent quality. Much of the purified quartz sand fails to meet the requirements of high-end manufacturing industries such as photovoltaics, semiconductors, communications, and defense. To meet these requirements, the purification cycle needs to be extended, leading to high energy consumption and costs. Even with extended purification cycles, it may still be impossible to obtain quartz sand that meets the specific needs of these industries. Therefore, there is an urgent need in the field for a method for purifying quartz sand that is energy-efficient, low-cost, and highly effective, as well as a purification apparatus that can implement such a method. Summary of the Invention

[0003] This invention provides a microwave purification device, purification method, and high-purity quartz sand to solve the problems of high energy consumption, high cost, and low purification efficiency of existing quartz sand purification methods.

[0004] On one hand, the present invention provides a microwave purification device for quartz sand, including a microwave generating mechanism, a feeding mechanism, and a shell. The inner wall of the shell forms an ellipsoidal cavity. The shell includes an upper shell and a lower shell, which are detachably connected. The upper shell is provided with an outlet pipe extending into the ellipsoidal cavity and several feed pipes extending into the ellipsoidal cavity. The lower shell is provided with a feeding mechanism positioning component corresponding to the position of the major semi-axis of the ellipsoidal cavity. The microwave generating mechanism extends into the ellipsoidal cavity from the position of the upper shell corresponding to the position of the major semi-axis of the ellipsoidal cavity. The microwave generating position of the microwave generating mechanism is located at the upper focus of the ellipsoidal cavity. The feeding mechanism includes a material tray and a storage tank located below the material tray. The material tray is connected to the storage tank, and the bottom of the material tray is provided with an opening.

[0005] Compared with the prior art, the present invention has the following beneficial effects: The purification device of the present invention has an ellipsoidal cavity. Through the dual-focal structure of the ellipsoidal cavity, and in conjunction with the microwave generating mechanism, the microwave generating position is set at the upper focal point of the ellipsoidal cavity. After the microwave generating mechanism is started, microwaves are emitted from the upper focal point, reflected within the ellipsoidal cavity, and finally converge at the lower focal point of the ellipsoidal cavity, achieving high-frequency, high-power, and low-loss microwave transmission. The microwave reception rate at the lower focal point is close to 100%. Based on the specific wavelengths of different microwave frequencies, microwave plasma spherical regions of different sizes are formed with the lower focal point as the center. In conjunction with the position of the loading tray, the microwave plasma spherical regions cover the loading tray's material area, maximizing the heating efficiency of the quartz sand in the loading tray, allowing the quartz sand to heat rapidly. Heating increases microwave utilization and heating efficiency, resulting in low energy consumption and cost. Based on this, the selective heating effect of microwave plasma causes a rapid increase in temperature and pressure of impurities such as gas-liquid inclusions in quartz sand, prompting the impurities to burst or generate microcracks at the interface between the impurities and the quartz sand matrix. This rapidly brings the quartz sand to the required state for water quenching. Combined with a storage tank (which can store acid solution), the microcracked quartz sand falls into the stored acid solution. Water quenching further promotes the extension of microcracks in the gas-liquid inclusions, and acid washing removes the impurities from the gas-liquid inclusions, significantly saving time and costs. This integrated microwave-water quenching-acid washing process improves purification efficiency and can also be combined with chlorination treatment. After rapidly heating the quartz sand with microwaves, chlorination is performed to further enhance the purification effect.

[0006] In some embodiments of the present invention, both the upper and lower housings have flanges at their open ends, and the upper and lower housings are connected by bolts and nuts through mounting holes on the flanges; and / or, one end of the feed pipe extending into the ellipsoidal cavity faces the lower focus of the ellipsoidal cavity; and / or, the positioning element of the material placement mechanism is groove-shaped, and its shape matches the outer surface of the storage tank, allowing the storage tank to be embedded in the positioning element. The flanges facilitate the connection and disassembly of the upper and lower housings; the feed pipe facing the lower focus of the ellipsoidal cavity facilitates control of the material input direction, facilitates the introduction of quartz sand into the loading tray, and ensures sufficient contact between the quartz sand and the introduced gas. The positioning element of the material placement mechanism facilitates the positioning of the material placement mechanism.

[0007] In some embodiments of the present invention, the microwave generating mechanism employs a 2.45 GHz solid-state microwave source or a 915 MHz solid-state microwave source. When the material placement mechanism is placed on the positioning component of the material placement mechanism via a storage trough, the material placement mechanism is located on the major semi-axis of the ellipsoidal cavity. When the microwave generating mechanism employs a 2.45 GHz solid-state microwave source, the distance from the upper surface of the material tray to the lower focal point of the ellipsoidal cavity is 30–45 mm, and 5 cm ≤ the diameter of the upper end face of the material tray ≤ 10 cm. When the microwave generating mechanism employs a 915 MHz solid-state microwave source, the distance from the upper surface of the material tray to the lower focal point of the ellipsoidal cavity is 75–125 mm, and 5 cm ≤ the diameter of the upper end face of the material tray ≤ 15 cm. Using a 2.45 GHz or 915 MHz solid-state microwave source results in better microwave heating and is more conducive to the rapid heating of the quartz sand. When using a 2.45 GHz solid-state microwave source, the corresponding wavelength is 12.24 cm. The diameter of the microwave plasma sphere centered at the lower focal point is Dmax = λ / 2 = 6.12 cm. By designing the distance from the upper surface of the loading plate to the lower focal point of the ellipsoidal cavity to be 30–45 mm, while ensuring that 5 cm ≤ the diameter of the upper end face of the loading plate ≤ 10 cm, the spherical microwave plasma region can cover the loading plate's material-containing area, maximizing the heating efficiency of the quartz sand in the loading plate. When using a 915 MHz solid-state microwave source, the corresponding wavelength is 33 cm. The diameter of the microwave plasma sphere centered at the lower focal point is Dmax = λ / 2 = 16.5 cm. By designing the distance from the upper surface of the loading plate to the lower focal point of the ellipsoidal cavity to be 75–125 mm, while ensuring that 5 cm ≤ the diameter of the upper end face of the loading plate ≤ 15 cm, the spherical microwave plasma region can cover the loading plate's material-containing area, maximizing the heating efficiency of the quartz sand in the loading plate.

[0008] In some embodiments of the present invention, the material tray and the storage tank are detachably connected. A material tray connecting seat is spaced apart on the outer surface of the material tray, and a storage tank connecting seat is spaced apart on the upper part of the storage tank. Both the material tray connecting seat and the storage tank connecting seat are provided with mounting through holes. The material tray and the storage tank can be connected via elastic elements of different specifications through these mounting through holes. The detachable connection between the material tray and the storage tank facilitates the replacement of elastic elements of different lengths to adjust the distance between the material tray and the storage tank, thereby enabling adjustment of the distance between the upper surface of the material tray and the lower focus of the ellipsoidal cavity.

[0009] In some embodiments of the present invention, a feeding channel is connected below the material tray, the feeding channel communicating with an opening at the bottom of the material tray, and the length of the feeding channel is ≤20cm; an opening switch is provided at the opening, and a vibration mechanism is provided on the feeding channel. The feeding channel provides a path for the quartz sand to fall into the storage tank, preventing the quartz sand from falling directly from the opening and scattering and failing to fall into the storage tank; the length of the feeding channel is ≤20cm to prevent excessive cooling due to a long falling distance, which would affect the water rinsing and pickling effect; the opening switch can control whether the opening is open or not, opening only when the quartz sand is heated to the required temperature, facilitating the control of the quartz sand temperature during falling; the vibration mechanism provides the material tray with vibration function, achieving uniform spreading and smooth falling of the quartz sand on the material tray through vibration, which is beneficial for controlling the time and temperature of the quartz sand after microwave plasma treatment.

[0010] On the other hand, the present invention also provides a microwave purification method for quartz sand, comprising the following steps: S1, crushing-screening: crushing and screening quartz ore to obtain quartz raw sand of a preset size; S2, initial purification: initially purifying the quartz raw sand by means of magnetic separation, flotation, and acid washing; S3, integrated microwave-water rinsing-acid washing purification: using the microwave purification device for quartz sand described in any of the above, placing the acid solution in a storage tank, placing the feeding mechanism on the feeding mechanism positioning part of the lower shell, sealing the upper shell and the lower shell to make the ellipsoidal cavity in a sealed state, evacuating the air through the air outlet pipe until the air pressure in the ellipsoidal cavity reaches the first preset air pressure, then introducing HCl gas into the ellipsoidal cavity through the feed pipe until the air pressure in the ellipsoidal cavity reaches the second preset air pressure, starting the microwave generating mechanism, and introducing HCl gas and the quartz sand obtained in the previous step into the ellipsoidal cavity through different feed pipes respectively, the quartz sand falling into the loading tray and being heated by the microwave generating mechanism and then... Acid washing with water is performed in the acid solution that falls into the storage tank through the opening; S4, Microwave-chlorination purification treatment: Using another of the above-mentioned quartz sand microwave purification devices, the feeding mechanism is placed on the feeding mechanism positioning part of the lower shell, the upper shell and the lower shell are sealed to make the ellipsoidal cavity in a sealed state, and the gas pressure in the ellipsoidal cavity is evacuated through the gas outlet pipe until the gas pressure in the ellipsoidal cavity reaches the third preset gas pressure. Then, the gas in the ellipsoidal cavity is extracted from the gas outlet pipe of the quartz sand microwave purification device used in S3, and the extracted gas is passed through S... 4. In the microwave purification device for quartz sand, any feed pipe is introduced into the ellipsoidal cavity, while O2 and Cl2 are simultaneously introduced into the ellipsoidal cavity through other feed pipes until the gas pressure in the ellipsoidal cavity reaches the fourth preset gas pressure. The microwave generating mechanism is then activated, and the extracted gas, O2, Cl2, and the quartz sand obtained from the previous purification step are introduced into the ellipsoidal cavity through different feed pipes. The quartz sand falls into the loading tray and is heated by the microwave generating mechanism before falling into the storage tank through the opening, thus completing the microwave-chlorination purification process.

[0011] Compared with the prior art, the present invention has the following beneficial effects: The microwave purification method for quartz sand of the present invention applies the microwave purification device of the present invention in both the integrated microwave-water rinsing-acid washing and microwave-chlorination purification stages, causing the quartz sand to heat up rapidly. In the integrated microwave-water rinsing-acid washing stage, with the help of selective heating by microwave plasma, the temperature and pressure of impurities such as gas-liquid inclusions in the quartz sand rise sharply, subsequently causing thermal explosion, or the difference in thermal expansion coefficient between the impurities and the quartz sand matrix causes microcracks to form between the impurities and the matrix interface, bringing the quartz sand to a water-rich state in a very short time. The purification process, in conjunction with the design of storage tanks, involves preparing quartz sand and placing it into an acid solution stored in the tank. Water quenching promotes the extension of microcracks at the interface, followed by acid washing to remove impurities from the gas-liquid inclusions. This process boasts high purification efficiency, high purification degree, and higher purity of the treated quartz sand. In the microwave-chlorination purification stage, the quartz sand can be rapidly heated, allowing for the chlorination purification of impurities using reaction gases. Furthermore, the reaction gases can be reused from the ellipsoidal cavity after the integrated microwave-water purification-acid washing process, reducing costs and achieving high purification efficiency and degree, resulting in even higher purity of the treated quartz sand.

[0012] This invention introduces a chlorinating agent (HCl gas). In the integrated microwave-water rinsing-acid washing purification stage, HCl can combine with impurities in quartz sand, converting them into a gaseous or condensed phase, thereby removing the impurities from the quartz sand and initially removing a certain amount of metallic impurities. This prepares the material for the next stage of water rinsing and acid washing, improving removal efficiency and probability. Simultaneously, HCl gas can be used as one of the working gases in the next stage of microwave-chlorination purification, thus reducing costs. Furthermore, the quartz sand sample kept warm after microwave roasting does not need to be transferred, avoiding heat loss. Direct water quenching and acid washing ensures a cooling effect, which is beneficial for crack propagation, thereby improving acid washing efficiency. In the microwave-chlorination purification stage, compared to a solid chlorine source, the introduction of a gaseous chlorine source can completely coat the surface of the quartz sand, greatly increasing the contact area between the chlorine source and impurities in the quartz sand. This facilitates the aggregation of the impurity phase, allowing it to detach from the quartz sand matrix, thus improving the efficiency of chlorination roasting. The purification method of this invention is applicable to the purification of quartz ore from different regions or from the same region with inconsistent quality. Compared with the prior art, it has a better purification effect and the purified quartz sand can achieve better purity.

[0013] In some embodiments of the present invention, the preset size is 50–425 μm; and / or, the acid solution in S3 is a mixed aqueous solution of hydrochloric acid and nitric acid, wherein the weight ratio of hydrochloric acid to nitric acid in the acid solution is 1:(1–1.5), the concentration of hydrochloric acid is 1.5–2.0 mol / L, the concentration of nitric acid is 1.5–2.0 mol / L, and the weight ratio of quartz sand falling into the storage tank to the acid solution is 1:(3–8); and / or, when the quartz sand obtained after purification in the previous step is introduced into S3–S4, the material tray is vibrated by a vibration mechanism on the feeding channel connected to the bottom of the material tray and communicating with the opening at the bottom of the material tray; and / or, both the first preset air pressure and the third preset air pressure are ≤1×10⁻⁶. -2 The second preset pressure is 13333–34666 Pa, and the fourth preset pressure is 6666.5–23000 Pa. Screening the quartz sand to a size of 50–425 μm is beneficial for improving the purification efficiency and effect of the integrated microwave-water rinsing-acid washing and microwave-chlorination purification stages. The acid solution is a mixed aqueous solution of hydrochloric acid and nitric acid. The strong oxidizing property of nitric acid causes metal impurities on the surface of the quartz sand to react with it to form nitrates. The nitrates containing metal ions have high solubility in water. Prolonged acid washing can remove the nitrate impurities from the quartz sand. In addition, hydrochloric acid provides a strongly acidic environment, simultaneously removing Fe from the quartz sand. The combination of the two acids not only avoids damage to the quartz sand but also improves the impurity removal effect. The design of the acid solution and the amount of quartz sand used ensures sufficient acid washing effect and efficiency. Excessive acid solution will cause unnecessary additional costs, while insufficient acid solution will result in poor acid washing effect. The vibration mechanism provides vibration function, which realizes the uniform spreading and smooth falling of quartz sand on the loading tray through vibration, so as to facilitate the control of the time and temperature of microwave plasma treatment / chlorination treatment of quartz sand.

[0014] In some embodiments of the present invention, when a 2.45 GHz solid-state microwave source is used as the microwave generating mechanism, the flow rate of HCl gas introduced into S3 is 0.1–1.5 L / min, the rate of introducing the purified quartz sand obtained in the previous step is 0.5–2.5 kg / min, and the quartz sand is heated to 950–1200 °C by the microwave generating mechanism; the flow rate ratio of O2 introduced into S4 to the gas introduced into the ellipsoidal cavity of S3 is (0.1–2.4):100, the flow rate ratio of Cl2 introduced into S4 to the gas introduced into the ellipsoidal cavity of S3 is (3–20):100, the rate of introducing the purified quartz sand obtained in the previous step is 0.5–2.5 kg / min, and the quartz sand is heated to 800–1000 °C by the microwave generating mechanism.

[0015] In some embodiments of the present invention, when a 915MHz solid-state microwave source is used as the microwave generating mechanism, the flow rate of HCl gas introduced into S3 is 0.35-6.5L / min, the rate of introducing the purified quartz sand obtained in the previous step is 1.5-10kg / min, and the quartz sand is heated to 950-1200℃ by the microwave generating mechanism; the flow rate ratio of O2 introduced into S4 to the gas introduced into the ellipsoidal cavity of S3 is (0.1-2.4):100, the flow rate ratio of Cl2 introduced into S4 to the gas introduced into the ellipsoidal cavity of S3 is (3-20):100, the rate of introducing the purified quartz sand obtained in the previous step is 1.5-10kg / min, and the quartz sand is heated to 800-1000℃ by the microwave generating mechanism.

[0016] When the present invention uses a 2.45GHz solid-state microwave source or a 915MHz solid-state microwave source, and performs microwave-water rinsing-acid washing integrated purification treatment and microwave-chlorination purification treatment stages with the above-mentioned gas flow rate, quartz sand introduction speed, heating temperature, and reaction gas flow ratio, the microwave heating effect on quartz sand is better, the contact time between quartz sand and reaction gas, acid solution, etc. is better, which is more conducive to the purification of quartz sand.

[0017] On the other hand, the present invention also provides a high-purity quartz sand, which is obtained by purifying quartz sand according to any one of the above-described microwave purification methods. The high-purity quartz sand of the present invention has high purity, meeting the requirements of high-end manufacturing industries such as photovoltaics, semiconductors, communications, and national defense. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments of the present invention will be described below.

[0019] Figure 1 This is a perspective view of a microwave purification apparatus for quartz sand according to an embodiment of the present invention, wherein the material feeding mechanism positioning component, the material tray connecting seat, the storage tank connecting seat, and the elastic component are not shown.

[0020] Figure 2 This is a cross-sectional view of a microwave purification device for quartz sand according to an embodiment of the present invention, through the plane containing its long semi-axis and the center of the feed pipe.

[0021] Figure 3 The flowchart shows a method for microwave purification of quartz sand according to an embodiment of the present invention, wherein a schematic diagram of the microwave purification device for quartz sand according to an embodiment of the present invention is shown in the process of microwave-water rinsing-acid washing integrated purification treatment and microwave-chlorination purification treatment.

[0022] Figure 4This is a comparison image showing the bubbling process after heating of purified quartz sand and unpurified quartz sand obtained by the microwave purification method of one embodiment of the present invention. Figure 4 (a) is a bubble state diagram of unpurified quartz sand after heating, and (b) is a bubble state diagram of quartz sand purified by the microwave purification method of quartz sand according to an embodiment of the present invention after heating. Detailed Implementation

[0023] To make the objectives, technical solutions and advantages of the present invention clearer, the various aspects of the present invention will be described in detail below with reference to specific embodiments. However, these specific embodiments are only used to illustrate the present invention and do not constitute any limitation on the scope of protection and the substantive content of the present invention.

[0024] Example 1

[0025] This embodiment provides a microwave purification device for quartz sand, such as... Figure 1-2 As shown, the device includes a microwave generating mechanism 1, a feeding mechanism 2, and a housing 3. The inner wall of the housing 3 forms an ellipsoidal cavity. The housing 3 includes an upper housing 31 and a lower housing 32, which are detachably connected. The upper housing 31 is provided with an exhaust pipe 311 extending into the ellipsoidal cavity and several feed pipes 312 extending into the ellipsoidal cavity. The lower housing 32 is provided with a feeding mechanism positioning element 321 corresponding to the position of the major semi-axis of the ellipsoidal cavity. In this embodiment, the number of feed pipes 312 is not limited and can be set as needed. Preferably, valve switches are provided on the exhaust pipe 311 and the feed pipes 312 to control the opening and closing of the exhaust pipe 311 and the feed pipes 312. Preferably, one end of the feed pipe 312 extending into the ellipsoidal cavity faces the lower focus of the ellipsoidal cavity. In this embodiment, the detachable connection method of the upper housing 31 and the lower housing 32 is not limited. For example, both the upper housing 31 and the lower housing 32 are provided with flanges 33 at their open ends, and the upper housing 31 and the lower housing 32 are connected by bolts and nuts through the mounting holes on the flanges 33. Preferably, a seal can be provided at the connection.

[0026] In this embodiment, the microwave generating mechanism 1 extends into the ellipsoidal cavity from the upper housing 31 at a position corresponding to the major semi-axis of the ellipsoidal cavity, and the microwave generating position 11 of the microwave generating mechanism 1 is located at the upper focus of the ellipsoidal cavity. In this embodiment, the specific structure of the microwave generating mechanism 1 is not limited and commercially available products can be used. In this embodiment, preferably, the microwave generating mechanism 1 uses a 2.45 GHz solid-state microwave source or a 915 MHz solid-state microwave source.

[0027] In this embodiment, the material placement mechanism 2 includes a material tray 21 and a storage trough 22 located below the material tray 21. The material tray 21 is connected to the storage trough 22, and the bottom of the material tray 21 has an opening. In this embodiment, preferably, the positioning member 321 of the material placement mechanism is groove-shaped, and the shape of the positioning member 321 matches the outer surface of the storage trough 22, so that the storage trough 22 can be embedded in the positioning member 321.

[0028] In this embodiment, when the material placement mechanism 2 is placed on the material placement mechanism positioning member 321 via the storage slot 22, the material placement mechanism 2 is located on the major semi-axis of the ellipsoidal cavity, and the material tray 21 is located below the lower focal point. When the microwave generating mechanism 1 uses a 2.45GHz solid-state microwave source, the distance H between the upper surface of the material tray 21 and the lower focal point of the ellipsoidal cavity is 30-45mm, and 5cm ≤ the diameter of the upper end face of the material tray ≤ 10cm; when the microwave generating mechanism 1 uses a 915MHz solid-state microwave source, the distance H between the upper surface of the material tray 21 and the lower focal point of the ellipsoidal cavity is 75-125mm, and 5cm ≤ the diameter of the upper end face of the material tray ≤ 15cm.

[0029] In this embodiment, the material tray 21 and the storage compartment 22 are detachably connected. The outer surface of the material tray 21 is provided with a material tray connecting seat 211 at intervals, and the upper part of the storage compartment 22 is provided with a storage compartment connecting seat at intervals. Both the material tray connecting seat 211 and the storage compartment connecting seat are provided with mounting through holes. The material tray 21 and the storage compartment 22 can be connected via these mounting through holes using elastic elements 23 of different specifications. In this embodiment, the elastic elements 23 of different specifications can be springs of different lengths, so as to adjust the distance between the upper surface of the material tray 21 and the lower focus of the ellipsoidal cavity according to actual needs.

[0030] In this embodiment, a feeding channel 24 is connected below the material tray 21. The feeding channel 24 communicates with the opening at the bottom of the material tray 21, and the length of the feeding channel is ≤20cm. An opening switch 25 is provided at the opening. In this embodiment, the specific form of the opening switch is not limited, as long as it can block and open the opening. Preferably, the opening switch is electrically connected to an external control device. Alternatively, the opening switch can also be a load-bearing switch, for example, a valve-shaped switch. The valve-shaped switch includes several spring pieces arranged circumferentially around the inner wall of the opening. One end of the spring piece is connected to the inner wall of the opening, and the end of the spring piece away from the inner wall of the opening is a free end. In this embodiment, preferably, a vibration mechanism 26 is provided on the feeding channel 24. The specific form of the vibration mechanism is not limited and commercially available products can be used. Preferably, the vibration mechanism is electrically connected to an external control device to control its vibration frequency. In this embodiment, preferably, a temperature sensor can be provided on the outer surface of the material tray 21. The temperature sensor is electrically connected to an external control device to facilitate accurate acquisition of the opening timing of the opening switch.

[0031] This embodiment also provides a microwave purification method for quartz sand, such as... Figure 3 As shown, it includes the following steps:

[0032] S1. Crushing and Screening Process: The quartz ore is crushed and screened to obtain quartz raw sand of a preset size. In this embodiment, the quartz ore can be crushed through three processes: jaw crusher, cone crusher, and roller crusher. The crushed quartz sand is screened to a suitable particle size, generally controlled within a preset size of 50-425 μm. The corresponding screen mesh size is ∈ [300, 40] mesh. Preferably, the preset size is ∈ [75, 250] μm, and the screen mesh size is ∈ [200, 60] mesh.

[0033] S2. Initial Purification Treatment: The raw quartz sand is initially purified using methods including magnetic separation, flotation, and acid washing. In this embodiment, the quartz sand of the preset size obtained after screening is subjected to magnetic separation using a high-intensity magnetic separator to remove weakly magnetic impurities. Then, flotation is performed to remove non-magnetic associated impurities. Finally, taking advantage of the relatively stable chemical properties of quartz, the surface of the quartz sand is further purified by acid washing with a mixture of hydrochloric acid and nitric acid.

[0034] S3. Integrated Microwave-Water Extraction-Acid Washing Purification Process: Using the quartz sand microwave purification device of this embodiment, the acid solution is placed in the storage tank, the feeding mechanism is placed on the feeding mechanism positioning part of the lower shell, the upper shell and the lower shell are sealed to make the ellipsoidal cavity in a sealed state, the air pressure in the ellipsoidal cavity reaches the first preset air pressure through the air outlet pipe, and then HCl gas is introduced into the ellipsoidal cavity through the feed pipe until the air pressure in the ellipsoidal cavity reaches the second preset air pressure. The microwave generating mechanism is started, and HCl gas and the quartz sand obtained from the previous step of purification are introduced into the ellipsoidal cavity through different feed pipes. The quartz sand falls into the loading tray and is heated by the microwave generating mechanism. After that, it falls into the acid solution in the storage tank through the opening for water extraction and acid washing.

[0035] In this embodiment, the acid solution in S3 is a mixed aqueous solution of hydrochloric acid and nitric acid, wherein the weight ratio of hydrochloric acid to nitric acid in the acid solution is 1:(1-1.5), the concentration of hydrochloric acid is 1.5-2.0 mol / L, the concentration of nitric acid is 1.5-2.0 mol / L, and the weight ratio of quartz sand falling into the storage tank to the acid solution is 1:(3-8); and / or, when the quartz sand obtained after purification in the previous step is introduced into S3, the material tray is vibrated by a vibration mechanism on the feeding channel connected to the bottom opening of the material tray; and / or, the first preset air pressure is ≤1×10 -2 Pa, the second preset air pressure is 13333~34666 Pa; and / or, the material tray is a quartz material tray, the material is high-purity quartz glass or ceramic, and the purity is ≥99.995%.

[0036] In this embodiment, when a 2.45 GHz solid-state microwave source is used as the microwave generator, the flow rate of HCl gas introduced in step S3 is 0.1–1.5 L / min, the rate at which the purified quartz sand obtained in the previous step is introduced is 0.5–2.5 kg / min, and the quartz sand is heated to 950–1200°C by the microwave generator. When a 915 MHz solid-state microwave source is used as the microwave generator, the flow rate of HCl gas introduced in step S3 is 0.35–6.5 L / min, the rate at which the purified quartz sand obtained in the previous step is introduced is 1.5–10 kg / min, and the quartz sand is heated to 950–1200°C by the microwave generator. Specifically, the process parameter relationships are shown in Table 1 below, depending on the specifications of the different microwave sources.

[0037] Table 1 Process parameters for step S3 under different microwave source specifications

[0038]

[0039]

[0040] S4. Microwave-chlorination purification treatment: Using another embodiment of the quartz sand microwave purification device, the feeding mechanism is placed on the feeding mechanism positioning part of the lower shell, and the upper shell and lower shell are sealed to make the ellipsoidal cavity in a sealed state. After the gas pressure in the ellipsoidal cavity reaches the third preset gas pressure through the gas outlet pipe, the gas in the ellipsoidal cavity is extracted from the gas outlet pipe of the quartz sand microwave purification device used in S3. The extracted gas is introduced into the ellipsoidal cavity through any feed pipe of the quartz sand microwave purification device used in S4. At the same time, O2 and Cl2 are introduced into the ellipsoidal cavity through other feed pipes until the gas pressure in the ellipsoidal cavity reaches the fourth preset gas pressure. The microwave generating mechanism is started, and the extracted gas, O2, Cl2 and the quartz sand obtained after purification in the previous step are introduced into the ellipsoidal cavity through different feed pipes. The quartz sand falls into the loading tray and is heated by the microwave generating mechanism and then falls into the storage tank through the opening, completing the microwave-chlorination purification treatment.

[0041] In this embodiment, the gas in the S3 ellipsoidal cavity can be extracted and stored in a gas storage device. When the pressure in the S3 ellipsoidal cavity is around normal, the shell is opened to take out the quartz sand in the acid solution, which is then dried and used as the purification target for S4. The gas extracted from the S3 ellipsoidal cavity is then extracted from the gas storage device and introduced into the microwave purification device for quartz sand used in S4.

[0042] In this embodiment, when the quartz sand obtained after purification in the previous step is introduced at S4, the material carrier is vibrated by a vibration mechanism on the feeding channel connected to the bottom opening of the material carrier; and / or, the third preset air pressure is ≤1×10 -2Pa, the fourth preset air pressure is 6666.5~23000Pa.

[0043] In this embodiment, when the microwave generating mechanism uses a 2.45GHz solid-state microwave source, the flow rate ratio of O2 introduced into S4 to the gas introduced into the ellipsoidal cavity of S3 is (0.1~2.4):100, the flow rate ratio of Cl2 introduced into the ellipsoidal cavity of S3 is (3~20):100, the rate at which the quartz sand obtained after purification in the previous step is introduced is 0.5~2.5kg / min, and the quartz sand is heated to 800~1000℃ by the microwave generating mechanism. When a 915MHz solid-state microwave source is used in the microwave generating mechanism, the flow rate ratio of O2 introduced into S4 to the gas introduced into the ellipsoidal cavity of S3 is (0.1~2.4):100, the flow rate ratio of Cl2 introduced into the ellipsoidal cavity of S3 is (3~20):100, the rate at which the purified quartz sand obtained in the previous step is introduced is 1.5~10kg / min, and the quartz sand is heated to 800~1000℃ by the microwave generating mechanism. Specifically, the process parameter relationships are shown in Table 2 below, depending on the specifications of different microwave sources.

[0044] Table 2 Process parameters for step S4 under different microwave source specifications

[0045]

[0046]

[0047] In this embodiment, preferably, steps S2-S4 can be repeated or repeated multiple times depending on the actual situation until the quartz sand purity is qualified.

[0048] This embodiment also provides a high-purity quartz sand, which is purified according to the microwave purification method for quartz sand in this embodiment.

[0049] Example 2

[0050] This embodiment provides a microwave purification apparatus for quartz sand, a microwave purification method for quartz sand using the apparatus, and high-purity quartz sand purified by the method. This embodiment differs from Embodiment 1 only in some process parameters of the microwave purification method; similarities are not repeated, and only the differences are described.

[0051] In the microwave purification method for quartz sand in this embodiment:

[0052] S1. Crushing and screening process: The quartz ore is crushed and screened to obtain raw quartz sand with a preset size of 75μm.

[0053] In the acid solution in S3, the weight ratio of hydrochloric acid to nitric acid is 1:1, the concentration of hydrochloric acid is 1.5 mol / L, the concentration of nitric acid is 1.5 mol / L, and the weight ratio of quartz sand falling into the storage tank to the acid solution is 1:3; the first preset gas pressure is ≤1×10⁻⁶. -2 The second preset pressure is 13333 Pa. The microwave generator uses a 2.45 GHz solid-state microwave source. The flow rate of HCl gas introduced into S3 is 0.1 L / min, and the rate at which the purified quartz sand obtained in the previous step is introduced is 0.5 kg / min. The quartz sand is heated to 950°C by the microwave generator. Specifically, the process parameter relationships are shown in Table 3 below.

[0054] Table 3 Process parameters for step S3

[0055] Microwave source specifications 2.45GHz Microwave output power 4kw HCl gas flow rate 0.1L / min Quartz feed amount 0.5 kg / min Controlling the microwave heating temperature of quartz sand 950℃ Distance between the quartz loading disk ellipsoid and the lower focus 30mm Quartz Carrier Disk Vibration Frequency 1Hz

[0056] The third preset air pressure in S4 is ≤1×10 -2 The fourth preset gas pressure is 6666.5 Pa. The microwave generating mechanism uses a 2.45 GHz solid-state microwave source. The flow rate ratio of O2 introduced into S4 to the gas introduced into the ellipsoidal cavity of S3 is 0.1:100, and the flow rate ratio of Cl2 introduced into the ellipsoidal cavity of S3 is 3:100. The rate at which the quartz sand obtained after purification in the previous step is introduced is 0.5 kg / min. The quartz sand is heated to 800℃ by the microwave generating mechanism. Specifically, the process parameter relationships are shown in Table 4 below.

[0057] Table 4S4 Process Parameters

[0058]

[0059] In this embodiment, steps S2-S4 are repeated twice.

[0060] Example 3

[0061] This embodiment provides a microwave purification apparatus for quartz sand, a microwave purification method for quartz sand using the apparatus, and high-purity quartz sand purified by the method. This embodiment differs from Embodiment 2 only in some process parameters of the microwave purification method; similarities are not repeated, and only the differences are described.

[0062] In the microwave purification method for quartz sand in this embodiment:

[0063] The microwave generator in S3 uses a 915MHz solid-state microwave source. The flow rate of HCl gas introduced into S3 is 0.35L / min, and the rate at which the quartz sand obtained from the previous purification step is introduced is 1.5kg / min. Specifically, the process parameters are shown in Table 5 below.

[0064] Table 5. Process parameters for step S3

[0065]

[0066]

[0067] The microwave generator in S4 uses a 915MHz solid-state microwave source, and the rate at which the purified quartz sand obtained in the previous step is introduced into S4 is 1.5 kg / min. Specifically, the process parameters are shown in Table 6 below.

[0068] Table 6 Process parameters for step S4

[0069] Microwave source specifications 915MHz microwave output power 12kW Quartz feed amount 1.5 kg / min Distance between the quartz loading disk ellipsoid and the lower focus 75mm Quartz Carrier Disk Vibration Frequency 0.1Hz

[0070] Example 4

[0071] This embodiment provides a microwave purification apparatus for quartz sand, a microwave purification method for quartz sand using the apparatus, and high-purity quartz sand purified by the method. This embodiment differs from Embodiment 1 only in some process parameters of the microwave purification method; similarities are not repeated, and only the differences are described.

[0072] In the microwave purification method for quartz sand in this embodiment:

[0073] S1. Crushing and screening process: The quartz ore is crushed and screened to obtain raw quartz sand with a preset size of 150μm.

[0074] In the acid solution in S3, the weight ratio of hydrochloric acid to nitric acid is 1:1.25, the concentration of hydrochloric acid is 1.7 mol / L, the concentration of nitric acid is 1.7 mol / L, and the weight ratio of quartz sand falling into the storage tank to the acid solution is 1:5; the first preset gas pressure is ≤1×10⁻⁶. - 2 The second preset pressure is 20000 Pa. The microwave generator uses a 2.45 GHz solid-state microwave source. The flow rate of HCl gas introduced into S3 is 1.0 L / min, and the rate at which the quartz sand obtained from the previous purification step is introduced is 1.5 kg / min. The quartz sand is heated to 1000℃ by the microwave generator. Specifically, the process parameter relationships are shown in Table 7 below.

[0075] Table 7 Process parameters for step S3

[0076]

[0077]

[0078] The third preset air pressure in S4 is ≤1×10 -2The fourth preset gas pressure is 10000 Pa. The microwave generating mechanism uses a 2.45 GHz solid-state microwave source. The flow ratio of O2 introduced into S4 to the gas introduced into the ellipsoidal cavity of S3 is 1:100, and the flow ratio of Cl2 introduced into the ellipsoidal cavity of S3 is 10:100. The rate at which the quartz sand obtained after purification in the previous step is introduced is 1.5 kg / min. The quartz sand is heated to 900℃ by the microwave generating mechanism. Specifically, the process parameter relationships are shown in Table 8 below.

[0079] Table 8. Process parameters for step S4

[0080]

[0081] In this embodiment, steps S2-S4 are repeated 3 times.

[0082] Example 5

[0083] This embodiment provides a microwave purification apparatus for quartz sand, a microwave purification method for quartz sand using the apparatus, and high-purity quartz sand purified by the method. This embodiment differs from Embodiment 4 only in some process parameters of the microwave purification method; similarities are not repeated, and only the differences are described.

[0084] In the microwave purification method for quartz sand in this embodiment:

[0085] The microwave generator in S3 uses a 915MHz solid-state microwave source. The flow rate of HCl gas introduced into S3 is 3.5L / min, and the rate at which the quartz sand obtained from the previous purification step is introduced is 5kg / min. Specifically, the process parameters are shown in Table 9 below.

[0086] Table 9. Process parameters for step S3

[0087]

[0088]

[0089] The microwave generator in S4 uses a 915MHz solid-state microwave source, and the rate at which the purified quartz sand obtained in the previous step is introduced into S4 is 5 kg / min. Specifically, the process parameters are shown in Table 10 below.

[0090] Table 10 Process parameters for step S4

[0091] Microwave source specifications 915MHz Microwave output power 35kw Quartz feed amount 5kg / min Distance between the quartz loading disk ellipsoid and the lower focus 90mm Quartz Carrier Disk Vibration Frequency 8Hz

[0092] Example 6

[0093] This embodiment provides a microwave purification apparatus for quartz sand, a microwave purification method for quartz sand using the apparatus, and high-purity quartz sand purified by the method. This embodiment differs from Embodiment 1 only in some process parameters of the microwave purification method; similarities are not repeated, and only the differences are described.

[0094] In the microwave purification method for quartz sand in this embodiment:

[0095] S1. Crushing and screening process: The quartz ore is crushed and screened to obtain raw quartz sand with a preset size of 250μm.

[0096] In the acid solution in S3, the weight ratio of hydrochloric acid to nitric acid is 1:1.5, the concentration of hydrochloric acid is 2.0 mol / L, the concentration of nitric acid is 2.0 mol / L, and the weight ratio of quartz sand falling into the storage tank to the acid solution is 1:8; the first preset gas pressure is ≤1×10⁻⁶. -2 The second preset pressure is 34666 Pa. The microwave generator uses a 2.45 GHz solid-state microwave source. The flow rate of HCl gas introduced into S3 is 1.5 L / min, and the rate at which the purified quartz sand obtained in the previous step is introduced is 2.5 kg / min. The quartz sand is heated to 1200℃ by the microwave generator. Specifically, the process parameter relationships are shown in Table 11 below.

[0097] Table 11 Process parameters for step S3

[0098]

[0099]

[0100] The third preset air pressure in S4 is ≤1×10 -2 The fourth preset gas pressure is 23000 Pa. The microwave generating mechanism uses a 2.45 GHz solid-state microwave source. The flow rate ratio of O2 introduced into S4 to the gas introduced into the ellipsoidal cavity of S3 is 2.4:100, and the flow rate ratio of Cl2 introduced into the ellipsoidal cavity of S3 is 20:100. The rate at which the quartz sand obtained after purification in the previous step is introduced is 2.5 kg / min. The quartz sand is heated to 1000℃ by the microwave generating mechanism. Specifically, the process parameter relationships are shown in Table 12 below.

[0101] Table 12 S4 Process Parameters

[0102]

[0103] In this embodiment, steps S2-S4 are repeated 3 times.

[0104] This embodiment tests the high-purity quartz sand purified by the microwave purification method of this embodiment for impurities. The test results are shown in Table 13 below.

[0105] Table 13 Comparison of impurity content between raw quartz ore and high-purity quartz sand obtained in this embodiment.

[0106]

[0107]

[0108] As shown in Table 13, compared with the unrefined raw quartz ore, the high-purity quartz sand obtained after purification in this embodiment has extremely low impurity content. Some of the original impurities were not detected after purification, which further illustrates that the purification device of this embodiment has a good purification effect. Figure 4 This diagram shows a comparison of purified quartz sand and unpurified quartz sand after heating and bubble formation using the microwave purification method of this embodiment. Figure 4 It is known that raw quartz ore (unrefined quartz sand) contains a large number of impurities. The quartz sand purified by the microwave purification method of this embodiment has very low impurity content. The purification device of this embodiment is used for purification, and the purification effect is good.

[0109] Example 7

[0110] This embodiment provides a microwave purification apparatus for quartz sand, a microwave purification method for quartz sand using the apparatus, and high-purity quartz sand purified by the method. This embodiment differs from Embodiment 6 only in some process parameters of the microwave purification method; similarities are not repeated, and only the differences are described.

[0111] In the microwave purification method for quartz sand in this embodiment:

[0112] The microwave generator in S3 uses a 915MHz solid-state microwave source. The flow rate of HCl gas introduced into S3 is 6.5L / min, and the rate at which the quartz sand obtained from the previous purification step is introduced is 10kg / min. Specifically, the process parameters are shown in Table 14 below.

[0113] Table 14 Process parameters for step S3

[0114]

[0115]

[0116] The microwave generator in S4 uses a 915MHz solid-state microwave source, and the rate at which the purified quartz sand obtained in the previous step is introduced into S4 is 10 kg / min. Specifically, the process parameters are shown in Table 15 below.

[0117] Table 15 Process parameters for step S4

[0118] Microwave source specifications 915MHz Microwave output power 70kW Quartz feed amount 10kg / min Distance between the quartz loading disk ellipsoid and the lower focus 125mm Quartz Carrier Disk Vibration Frequency 15Hz

[0119] The present invention has been described above with reference to specific embodiments. These specific embodiments are merely exemplary and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make various modifications, changes, or substitutions without departing from the essence of the present invention. Therefore, various equivalent variations made according to the present invention still fall within the scope of the present invention.

Claims

1. A quartz sand microwave purification method, comprising using a quartz sand microwave purification device, wherein the quartz sand microwave purification device comprises a microwave generating mechanism, a material placing mechanism and a shell, an inner wall of the shell forms an ellipsoidal cavity, the shell comprises an upper shell and a lower shell, the upper shell and the lower shell are detachably connected, the upper shell is provided with a gas outlet pipe extending into the ellipsoidal cavity and a plurality of material inlet pipes extending into the ellipsoidal cavity, and the lower shell is provided with a material placing mechanism positioning member corresponding to a position of a long semi-axis of the ellipsoidal cavity.

2. The quartz sand microwave purification device according to claim 1, wherein the microwave generating mechanism extends into the ellipsoidal cavity from a position corresponding to a long semi-axis of the ellipsoidal cavity of the upper shell, and a microwave generating position of the microwave generating mechanism is located at an upper focal point of the ellipsoidal cavity.

3. The quartz sand microwave purification device according to claim 1 or 2, wherein the material placing mechanism comprises a material loading tray and a storage tank located below the material loading tray, the material loading tray is connected with the storage tank, and the bottom of the material loading tray is provided with an opening.

4. The quartz sand microwave purification method according to claim 1, further comprising the following steps: S1. Crushing and screening treatment: crushing and screening quartz ore to obtain quartz raw sand with a preset size; S2. Initial purification treatment: initially purifying the quartz raw sand by a purification method comprising magnetic separation, flotation and acid pickling; S3. Microwave-hydrolysis-acid pickling integrated purification treatment: applying the quartz sand microwave purification device, placing an acid solution in the storage tank, placing the material placing mechanism on the material placing mechanism positioning member of the lower shell, closing the upper shell and the lower shell to make the ellipsoidal cavity in a sealed state, vacuumizing through the gas outlet pipe until the gas pressure in the ellipsoidal cavity reaches a first preset gas pressure, then introducing HCl gas into the ellipsoidal cavity through the material inlet pipes until the gas pressure in the ellipsoidal cavity reaches a second preset gas pressure, starting the microwave generating mechanism, introducing HCl gas and quartz sand obtained after the previous step of purification into the ellipsoidal cavity through different material inlet pipes, the quartz sand falling into the material loading tray and being heated by the microwave generating mechanism and then falling into the acid solution in the storage tank through the opening to perform hydrolysis and acid pickling; S4. Microwave-chlorination purification treatment: applying the quartz sand microwave purification device, placing the material placing mechanism on the material placing mechanism positioning member of the lower shell, closing the upper shell and the lower shell to make the ellipsoidal cavity in a sealed state, vacuumizing through the gas outlet pipe until the gas pressure in the ellipsoidal cavity reaches a third preset gas pressure, then discharging the gas in the ellipsoidal cavity of the quartz sand microwave purification device applied in S3 from the gas outlet pipe thereof, introducing the discharged gas into the ellipsoidal cavity through any material inlet pipe of the quartz sand microwave purification device applied in S4, while introducing O2 and Cl2 into the ellipsoidal cavity through other material inlet pipes until the gas pressure in the ellipsoidal cavity reaches a fourth preset gas pressure, starting the microwave generating mechanism, introducing the discharged gas, O2, Cl2 and quartz sand obtained after the previous step of purification into the ellipsoidal cavity through different material inlet pipes, the quartz sand falling into the material loading tray and being heated by the microwave generating mechanism and then falling into the storage tank to complete the microwave-chlorination purification treatment. ​ ​ 2. The quartz sand microwave purification method according to claim 1, wherein The open ends of the upper shell and the lower shell are provided with flanges, the upper shell and the lower shell are connected through mounting holes on the flanges by means of a bolt-nut structure; and / or, one end of the feeding pipe extending into the ellipsoidal cavity is directed towards the lower focal point of the ellipsoidal cavity; and / or, the material placing mechanism positioning member is in the form of a groove, the shape of the material placing mechanism positioning member matches the outer surface of the storage groove, and the storage groove can be embedded in the material placing mechanism positioning member.

3. The quartz sand microwave purification method according to claim 1, wherein The microwave generating mechanism adopts a 2.45GHz solid-state microwave source or a 915MHz solid-state microwave source; When the material placing mechanism is placed in the material placing mechanism positioning member by means of the storage groove, the material placing mechanism is located on the major axis of the ellipsoidal cavity; and when the microwave generating mechanism adopts a 2.45GHz solid-state microwave source, the distance between the upper surface of the material loading disc and the lower focal point of the ellipsoidal cavity is 30-45mm, 5cm≤the diameter of the upper end surface of the material loading disc≤10cm; when the microwave generating mechanism adopts a 915MHz solid-state microwave source, the distance between the upper surface of the material loading disc and the lower focal point of the ellipsoidal cavity is 75-125mm, 5cm≤the diameter of the upper end surface of the material loading disc≤15cm.

4. The quartz sand microwave purification method according to claim 1, wherein The material loading disc and the storage groove are detachably connected, the outer surface of the material loading disc is provided with material loading disc connecting seats at intervals, the upper part of the storage groove is provided with storage groove connecting seats at intervals, mounting through holes are arranged on the material loading disc connecting seats and the storage groove connecting seats, and the material loading disc and the storage groove can be connected by means of the mounting through holes through different specifications of elastic members.

5. The quartz sand microwave purification method according to claim 1, wherein A discharging channel is further connected below the material loading disc, the discharging channel is in communication with the opening in the bottom of the material loading disc, and the length of the discharging channel is ≤20cm; An opening switch is arranged at the opening, and a vibrating mechanism is arranged on the discharging channel.

6. The quartz sand microwave purification method according to claim 1, wherein The preset size is 50-425 mu m; and / or, the acid solution in S3 is a mixed aqueous solution of hydrochloric acid and nitric acid, wherein the weight ratio of hydrochloric acid to nitric acid in the acid solution is 1:(1-1.5), the concentration of hydrochloric acid is 1.5-2.0 mol / L, the concentration of nitric acid is 1.5-2.0 mol / L, and the weight ratio of the quartz sand falling into the storage tank to the acid solution is 1:(3-8); and / or, when S3-S4 is connected to the quartz sand obtained after the previous purification, the vibration mechanism on the lower discharging channel connected to the opening at the bottom of the loading tray is used to vibrate the loading tray; and / or, the first preset air pressure and the third preset air pressure are both ≤1×10 -2 Pa, the second preset air pressure is 13333-34666 Pa, and the fourth preset air pressure is 6666.5-23000 Pa.

7. The quartz sand microwave purification method according to claim 1, wherein When the microwave generating mechanism adopts a 2.45GHz solid-state microwave source, the flow rate of the HCl gas introduced in S3 is 0.1-1.5L / min, the speed of the quartz sand obtained after purification in the previous step is 0.5-2.5kg / min, and the quartz sand is heated to 950-1200℃ by the microwave generating mechanism; in S4, the flow rate ratio of the introduced O2 to the gas introduced into the ellipsoidal cavity in S3 is (0.1-2.4):100, the flow rate ratio of the introduced Cl2 to the gas introduced into the ellipsoidal cavity in S3 is (3-20):100, the speed of the quartz sand obtained after purification in the previous step is 0.5-2.5kg / min, and the quartz sand is heated to 800-1000℃ by the microwave generating mechanism.

8. The quartz sand microwave purification method according to claim 1, wherein, When the microwave generating mechanism adopts a solid-state microwave source of 915 MHz, the flow rate of HCl gas introduced in S3 is 0.35-6.5 L / min, the flow rate of the quartz sand obtained after purification in the previous step is 1.5-10 kg / min, and the quartz sand is heated to 950-1200 DEG C by the microwave generating mechanism; in S4, the flow rate ratio of O2 to the gas introduced into the ellipsoidal cavity in S3 is (0.1-2.4):100, the flow rate ratio of Cl2 to the gas introduced into the ellipsoidal cavity in S3 is (3-20):100, the flow rate of the quartz sand obtained after purification in the previous step is 1.5-10 kg / min, and the quartz sand is heated to 800-1000 DEG C by the microwave generating mechanism.

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