Preparation process of ultra-high purity amorphous silicon dioxide synthetic quartz sand

Abstract

The present invention discloses a process for preparing ultra-high-purity amorphous silica synthetic quartz sand, comprising the following sequential steps: reacting amorphous silica, a mineralizer, and ultrapure water under high temperature and high pressure, discharging the reaction product, performing solid-liquid separation during discharging, grinding, pickling, cleaning, and drying to obtain an ultra-high-purity amorphous silica synthetic quartz sand product. The present invention utilizes the pressure within the reactor to achieve solid-liquid separation during discharging, eliminating the cost of purchasing a separate solid-liquid separation device. Because amorphous silica is used, its purity is high and controllable, which can alleviate the current shortage of high-quality quartz ore in my country. The purity of the quartz seed crystals used in the crystallization stage is also very high. Therefore, the ultra-high-purity quartz sand produced has a very low aluminum content and a low total amount of nine impurities, including aluminum, iron, potassium, sodium, calcium, magnesium, titanium, lithium, and zirconium.

Description

Technical Field

[0001] The present invention relates to silica; its hydrate, such as Lepi silicic acid, and in particular to a preparation process of ultra-high-purity amorphous silicon dioxide synthetic quartz sand. Background Art

[0002] In the paper "Overview of Synthetic Quartz Sand Process and Comparative Analysis of Test Data of Several Types of Quartz Sand" published in the 2nd issue of 2024 (total issue 164) of "China Non-metallic Mineral Industry Guide", Zhang Pengyuan mentioned that synthetic sand and Mitsubishi quartz sand are prepared using silicon-containing compounds as the main raw materials. The production process mainly includes: reaction synthesis, grinding, cleaning and other steps, which can produce high-purity amorphous silica quartz sand products.

[0003] Amorphous silica, also known as non-crystalline silica, lacks the ordered atomic arrangement found in crystalline silica. Its atoms are randomly distributed, without a well-defined crystal structure. The most common form of amorphous silica is fused quartz, formed by rapidly cooling molten silica. Other forms include aerogel, silica gel, and diatomaceous earth. Amorphous silica has lower density, lower hardness, and a lower melting point than crystalline silica.

[0004] Currently, ultra-high-purity quartz sand generally refers to materials with a size range of 40-70 mesh or 70-140 mesh, with SiO2 purity >99.9% and Fe2O3 (ppm) <2. Ultra-high-purity amorphous silica synthetic quartz sand is synthesized from amorphous silica through a reaction. Existing methods for preparing ultra-high-purity quartz sand include: manually sorting natural ore, using the selected premium quartz ore as the raw material for processing ultra-high-purity quartz sand, crushing and grading it, then manually sorting it again, grinding and grading it to separate the 40-70 mesh and 70-140 mesh particle sizes as the raw material for processing ultra-high-purity quartz sand. The processed raw material first undergoes strong magnetic separation, then flotation, and finally chemical treatment to remove contaminants on the surface and in the cracks of the silica sand to obtain the ultra-high-purity quartz sand product. Its raw materials are mainly natural minerals, which is a method of preparing ultra-high purity quartz sand from crystalline silicon dioxide. In order to achieve ultra-high purity quartz sand with a purity that meets the requirements, it is more dependent on the high quality of the original ore. Summary of the Invention

[0005] The present invention aims to overcome the shortcomings of the prior art by providing a process for preparing ultra-high-purity amorphous silica-derived quartz sand. This process utilizes pressure within the reactor to achieve simultaneous solid-liquid separation during unloading, eliminating the cost of purchasing a separate solid-liquid separation device. The use of amorphous silica, inherently high and controllable in purity, can alleviate my country's current shortage of high-quality quartz ore. The quartz seed crystals used in the crystallization stage are also of high purity. The resulting ultra-high-purity quartz sand has a very low aluminum content and low levels of nine impurities: aluminum, iron, potassium, sodium, calcium, magnesium, titanium, lithium, and zirconium.

[0006] To achieve the above objectives, the present invention provides a process for preparing ultra-high-purity amorphous silica synthetic quartz sand, comprising the following sequential steps: reacting amorphous silica, a mineralizer, and ultrapure water under high temperature and pressure, discharging the resulting product, performing simultaneous solid-liquid separation, grinding, pickling, cleaning, and drying to produce the ultra-high-purity amorphous silica synthetic quartz sand product. This simultaneous solid-liquid separation eliminates the cost of purchasing a separate solid-liquid separation device. The use of amorphous silica, with its inherent high and controllable purity, can alleviate my country's current shortage of high-quality quartz ore. The quartz seed crystals used in the crystallization stage are also of high purity. Consequently, the resulting ultra-high-purity quartz sand has a very low aluminum content and low total amounts of nine impurities, including aluminum, iron, potassium, sodium, calcium, magnesium, titanium, lithium, and zirconium.

[0007] A further technical solution involves placing amorphous silica, a mineralizer, and ultrapure water in a reactor for a high-temperature, high-pressure reaction. During discharge, the reactor's discharge port is opened, and the pressure within the reactor is used to drain the liquid through a filter at the discharge port, achieving simultaneous solid-liquid separation. The filter is then removed from the discharge port to remove the solids from the reaction product. This method utilizes the reactor's internal pressure for discharge and solid-liquid separation, eliminating the need for additional power devices and saving energy and equipment.

[0008] A further technical solution is to release the pressure bolts at the bottom of the reactor body before unloading to relieve the pressure. Since unloading is under pressure, the high pressure in the reactor body is first discharged to slightly above 1 atmosphere before unloading and solid-liquid separation, ensuring safety.

[0009] A further technical solution is to dry the cleaned material in a dryer or using hot air ejected from the pressure bolts during the pressure relief process in the production of a subsequent batch of ultra-high-purity amorphous silica synthetic quartz sand. Drying the material during pressure relief fully utilizes the reactor itself, eliminating the need for additional drying equipment, saving energy, and reducing equipment purchase costs.

[0010] A further technical solution is that the lower end of the reactor is connected to a discharge pipe, the outlet of the discharge pipe away from the reactor body is the discharge port, and the filter screen at the discharge port is a spherical crown-shaped metal filter screen that protrudes outward. The bottom size of the spherical crown of the spherical crown metal filter screen is larger than the size of the discharge port. The edge of the spherical crown metal filter screen is provided with an outward flange, and the inner wall of the discharge pipe near the discharge port is provided with an annular groove that adapts to the outward flange. With this arrangement, when the discharge port is opened, solid and liquid are sprayed out simultaneously, but the spherical crown metal filter screen intercepts the solid material, playing the role of solid-liquid separation by utilizing the pressure in the reactor. When the liquid is gone, the spherical crown metal filter screen can be removed to remove the solid.

[0011] A further technical solution involves removing the spherical metal filter after the solid-liquid separation process, pouring out the solid material on the spherical metal filter, grinding, pickling, and cleaning it, and then placing it back into the spherical metal filter. The spherical metal filter, carrying the solid material, is then placed on the pressure bolts used in the pressure relief process during the production of a subsequent batch of ultra-high-purity amorphous silica synthetic quartz sand for drying. After drying, the spherical metal filter can continue to be used for solid-liquid separation, or two spherical metal filters can be used, one as a backup and the other in use, allowing for flexible selection to suit actual on-site conditions.

[0012] The advantages and beneficial effects of the present invention are: utilizing the pressure in the reactor to discharge materials and perform solid-liquid separation, without requiring any additional power device, thus saving energy consumption and the number of equipment.

[0013] The pressure within the reactor is utilized to achieve solid-liquid separation during unloading, eliminating the cost of purchasing a separate solid-liquid separation device. The use of amorphous silica, inherently high and controllable in purity, can alleviate my country's current shortage of high-quality quartz ore. The quartz seed crystals used in the crystallization stage are also of high purity. The resulting ultra-high-purity quartz sand has very low aluminum content and low levels of nine impurities, including aluminum, iron, potassium, sodium, calcium, magnesium, titanium, lithium, and zirconium.

[0014] Since it is a pressurized unloading process, the high pressure in the kettle is first discharged until it is slightly greater than one atmosphere before discharging and solid-liquid separation, ensuring safety.

[0015] The material is dried during pressure relief, making full use of the reactor itself. No additional drying equipment is required, saving energy, eliminating the need for drying equipment, and reducing equipment purchase costs.

[0016] After this arrangement, when the discharge port is opened, the solid and liquid will spray out together, but the spherical crown metal filter will intercept the solid material, and use the pressure in the reactor to separate the solid and liquid. When the liquid is gone, the spherical crown metal filter can be removed to take out the solid.

[0017] After drying is completed, the spherical crown metal filter can still be used for solid-liquid separation, or two spherical crown metal filters can be used, one for backup and one for use, and flexible selection can be made to adapt to actual working conditions on site. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of a reaction kettle in Example 1 of a process for preparing ultra-high-purity amorphous silicon dioxide synthetic quartz sand according to the present invention;

[0019] Figure 2 yes Figure 1 The main view;

[0020] Figure 3 is a schematic diagram of the reactor in Example 2 of the present invention;

[0021] Figure 4 yes Figure 3 A partial enlarged schematic diagram of the discharge port at the lower end;

[0022] Figure 5 yes Figure 4 An enlarged schematic diagram of the mid-sphere crown metal filter;

[0023] Figure 6 is a schematic diagram of the reactor in Example 3 of the present invention;

[0024] Figure 7 yes Figure 6 Schematic diagram of the mid-sphere crown metal filter;

[0025] Figure 8 yes Figure 7 AA section view;

[0026] Figure 9 yes Figure 7 Schematic diagram of the decomposition;

[0027] Figure 10 yes Figure 8 Schematic diagram of the fixed pulley and its adjacent components;

[0028] Figure 11 yes Figure 10 Schematic diagram of the fixed pulley;

[0029] Figure 12 yes Figure 7 A partial enlarged schematic diagram of the fixed pulley and its adjacent components;

[0030] Figure 13 yes Figure 12 Schematic diagram after removing the outer parts of the metal ring and removing the metal ring, elastic wire and plastic film;

[0031] Figure 14 yes Figure 7Schematic diagram of the state of the ball crown net after tilting;

[0032] Figure 15 yes Figure 14 A partial enlarged schematic diagram of the elastic metal wire and its adjacent components;

[0033] Figure 16 yes Figure 15 A partial enlarged schematic diagram of the plastic film and its adjacent components;

[0034] Figure 17 yes Figure 16 Side view of the fixed pulley and the curved baffle;

[0035] Figure 18 It is a schematic diagram of a spherical crown-shaped metal filter with two hinge points offset at a certain angle;

[0036] Figure 19 Schematic diagram of the pickling reactor in Example 4 of the present invention;

[0037] Figure 20 yes Figure 19 Middle AA section view;

[0038] Figure 21 yes Figure 19 Schematic diagram of direction B.

[0039] In the figure: 1. Discharge port; 2. Pressure bolt; 3. Spherical crown metal filter; 4. Outer flange; 5. Spherical crown net; 6. Conical ring net; 7. Metal ring; 8. Fixed pulley; 9. Elastic metal wire; 10. Plastic film; 11. Axle; 12. Arc baffle; 13. Hinge point; 14. Pickling reactor; 15. Acid inlet; 16. Stirring shaft; 17. Reducer motor; 18. Stirring blade; 19. Loading plate; 20. Opening; 21. Inclined feed plate; 22. Opening. DETAILED DESCRIPTION

[0040] The following embodiments are further described in conjunction with the accompanying drawings and examples. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0041] Example 1: Figure 1 、 Figure 2 As shown, the present invention is a process for preparing ultra-high-purity amorphous silicon dioxide synthetic quartz sand, which comprises the following process steps performed in sequence: amorphous silicon dioxide, a mineralizer, and ultra-pure water (reaction under high temperature and high pressure), unloading, solid-liquid separation, (grinding) pickling, cleaning, and drying, to produce an ultra-high-purity amorphous silicon dioxide synthetic quartz sand product;

[0042] Amorphous silica, mineralizer, and ultrapure water are placed in a reactor for high-temperature and high-pressure reaction. During unloading, the discharge port 1 of the reactor is opened, and the pressure in the reactor is utilized (before unloading, the bottom pressure bolt 2 is first released to release a large part of the pressure in the reactor, but it is still slightly greater than one atmosphere, and then the discharge valve on the discharge pipe is opened) to discharge the liquid in the reactor through the filter at the discharge port 1 of the reactor (this is pressure unloading in nature), thereby achieving solid-liquid separation during unloading. The filter is then removed from the discharge port to remove the solid from the reaction product.

[0043] Utilize the pressure in the reactor to achieve solid-liquid separation during unloading, eliminating the cost of purchasing a separate solid-liquid separation device;

[0044] Before the unloading process, there is a process of releasing the pressure bolt 2 at the bottom of the reactor body to relieve the pressure of the reactor body;

[0045] The drying process is to use a dryer to dry the cleaned material or to use the hot air ejected from the pressure bolt 2 in the pressure relief process in the preparation process of the next batch of ultra-high purity amorphous silicon dioxide synthetic quartz sand products to dry the cleaned material;

[0046] The high temperature and high pressure reaction comprises:

[0047] Raw material preparation: Place amorphous silica, mineralizer, and ultrapure water into the first reactor;

[0048] Seal the first reactor: Seal the first reactor to ensure that the reaction is carried out under high temperature and high pressure;

[0049] Heating to a preset temperature: The dissolved material in the first reactor is pressed into the second reactor under high pressure (similar steps are performed before the pressure is injected, first releasing the pressure bolts at the bottom of the first reactor to vent the pressure to slightly above 1 atmosphere). Quartz seed crystals are then added to the second reactor. The temperature is raised to the preset synthesis condition temperature, and the pressure is increased to the preset pressure. The crystal growth is carried out at a constant temperature and pressure. The pressure in the second reactor is lower than that in the first reactor. The mineralizer is 95% sodium hydroxide and 25% ammonia water.

[0050] The use of amorphous silicon dioxide, which has high purity and is controllable, can alleviate the current shortage of high-quality quartz ore in my country. The purity of the quartz seed crystals used in the crystallization stage is also very high. Therefore, the ultra-high-purity quartz sand produced has a very low aluminum content and a low total amount of nine impurities including aluminum, iron, potassium, sodium, calcium, magnesium, titanium, lithium, and zirconium.

[0051] Unloading refers to unloading the second reactor after the reaction in the second reactor is completed; before unloading, the temperature and pressure in the reactor are gradually reduced, and the hot air ejected from the pressure bolts at the bottom of the reactor body is used to dry the materials in the preparation process of the previous batch of ultra-high purity amorphous silicon dioxide synthetic quartz sand products.

[0052] Example 2: The difference from Example 1 is that Figures 3 to 5 As shown, the lower end of the reactor is connected to a discharge pipe, the pipe opening of the discharge pipe away from the reactor body is the discharge port 1, the filter screen at the discharge port is a spherical crown metal filter screen 3 protruding outward, the bottom size of the spherical crown of the spherical crown metal filter screen is larger than the size of the discharge port, the edge of the spherical crown metal filter screen 3 is provided with an outer flange 4, and the inner wall of the discharge pipe near the discharge port is provided with an annular groove adapted to the outer flange;

[0053] The spherical crown metal filter can be made of stainless steel; when installing, pinch the outer flange 4 with appropriate force so that the spherical crown metal filter 3 can be inserted into the discharge port, and then continue to insert it into the discharge pipe until the outer flange is stuck in the ring groove and it is installed. After taking it off (the taking off action is the opposite of the above action), pour out the solid material on the spherical crown metal filter 3, and then grind, pickle, and clean it, and then place it directly on the pressure bolt 2 in the pressure relief process in the preparation process of the next batch of ultra-high purity amorphous silica synthetic quartz sand products. The material is dried by the hot air ejected from the pressure bolt during the pressure relief process in the preparation process of the next batch of ultra-high purity amorphous silica synthetic quartz sand products.

[0054] Example 3: The difference from Example 2 is that Figures 6 to 17 As shown (for ease of illustration, Figure 8 The arc-shaped baffle is not shown in the figure), the spherical crown metal filter 3 is composed of the lowest spherical crown net 5 and several cone ring nets 6 of gradually increasing size arranged in sequence from bottom to top. The upper edge of the spherical crown net, the lower edge of the uppermost cone ring net and the upper and lower edges of the remaining cone ring nets 6 are fixed with metal rings 7 with a U-shaped cross-section. The upper and lower adjacent metal rings 7 are hinged and every two upper and lower adjacent hinge points are staggered (the cone ring net refers to an annular net and this annular net has a certain taper in its length direction; a more preferred solution is not to stagger relative settings, but to stagger at a certain angle, such as 90°; that is, assuming that the spherical crown metal filter is composed of three parts, there are two hinge points, then the projection points of the two hinge points 13 on the ground are respectively perpendicular to the two lines connecting the projection points of the sphere center of the spherical crown metal filter on the ground; in this way, when the spherical crown net 5 and the cone ring net 6 above it are tilted, not only the directions are different, but also there are angles, such as Figure 18As shown, it can avoid the problem that the spherical crown net tilts to one side, while the conical ring net above tilts in the opposite direction after more solid materials accumulate; because it tilts in the opposite direction, the final combined effect is equal to not tilting, which will cause solid materials to accumulate in a local area of the filter screen and is not conducive to extending the life of the filter screen; therefore, the preferred composition of the spherical crown metal filter screen is four parts, so there are three hinge points. Except for the conical ring net at the top, the other three parts tilt in one direction respectively, which is conducive to extending the life of the spherical crown metal filter screen. The upper and lower adjacent metal rings 7 are symmetric in shape and the openings of the two metal rings are arranged opposite to each other. A fixed pulley 8 is rotatably arranged in the upper metal ring of the upper and lower adjacent metal rings. An elastic metal wire 9 is wound around the fixed pulley 8. One end of the elastic metal wire 9 is fixedly connected to the fixed pulley, and the other end is fixedly connected to the lower metal ring of the upper and lower adjacent metal rings. A plastic film 10 is also arranged between two upper and lower adjacent metal rings. The upper and lower edges of the plastic film 10 are respectively fixedly connected to the upper metal ring and the lower metal ring; except for the hinge points, the plastic film 10 almost covers the entire metal ring (so that when the elastic metal wire 9 is released from the fixed pulley 8 or the filter screen is pressed and tilted, the plastic film almost completely blocks the gap between the upper and lower adjacent conical ring nets; the liquid sprayed on the plastic film 10 will continue to flow downward and flow out through the spherical crown net 5); the plastic film is made of polyimide film or high-temperature resistant PET film; the elastic metal wire is made of nickel-based high-temperature resistant alloy 3J1 metal wire; to ensure the strength of the plastic film, several metal wires can be fixedly arranged at intervals on the film surface of the plastic film. The metal wires here are different from the aforementioned elastic metal wires, and the metal wires are arranged on the side of the plastic film away from the center of the filter screen (that is, the outer surface).

[0055] The fixed pulley 8 is rotatably arranged on the axle 11 fixedly connected inside the upper metal ring 7. The axle is in an inverted "冂" shape. The section of the axle located at the fixed pulley is a horizontal rod. Arc-shaped baffles 12 with smooth surfaces are fixedly arranged on the other two sections of the axle. The lower ends of the arc-shaped baffles 12 are respectively fixedly connected to the other two sections of the axle 11. A torsion spring can also be arranged on the axle. One end of the torsion spring is fixedly connected to the horizontal rod, and the other end is fixedly connected to the fixed pulley; the torsion spring is made of 250A53 spring steel; preferably three elastic metal wires are arranged. Too few may not be able to support the lower spherical crown net or conical ring net (especially after solid materials accumulate), and too many will be troublesome to install.

[0056] A deformable arc filter is movably provided at the discharge port. When the pressure is too great or a large amount of solids accumulate on the filter, the filter (referring to the spherical crown filter) bulges downward and outward (i.e., in the direction away from the autoclave body) to prevent the discharge port from being blocked by a large amount of solids and to prevent the filter (referring to the spherical crown metal filter 3) from being damaged when the pressure is too great. This can reduce the frequency of replacing the filter and save working time and labor because the filter replacement requires shutdown, cleaning, ventilation, etc.; it avoids the problem of the discharged material only accumulating locally on the large filter (the local area of ​​the filter is always under pressure) which in turn reduces the service life of the filter when a large filter is directly used; and because the upper and lower adjacent filter parts (such as adjacent cone rings; or between the spherical crown and cone ring) are staggered and hinged, when a large amount of solids accumulate in the lower spherical crown and overcome the elastic force of the elastic metal wire (if a torsion spring is also provided, the torsion is also overcome at the same time), the spherical crown tilts downward and toward its hinge point. Pulling out the plastic film and the elastic metal wire can, on the one hand, continue the solid-liquid separation (although the plastic film will block the liquid, it is only a small section after all, and most of the liquid still flows out from the mesh of the filter screens at other positions, such as the spherical crown net or the cone ring net). On the other hand, due to the inclination of the spherical crown net, the subsequent accumulated solid material falls directly below the current one (that is, the plastic film pulled out by the spherical crown net at this time). As the process continues, the solid material accumulates on the cone ring net above the spherical crown net (because the spherical crown net has previously accumulated a part or has been filled, if it is filled, the subsequent solid material will accumulate on the cone ring net; if it is not filled, part of the material will fall on the spherical crown net but also on the filter screen of the tilted spherical crown net, so it is avoided to accumulate in the local area of ​​the filter screen). When more solid material reaches the elastic force of the elastic metal wire on the metal ring on the cone ring net above the spherical crown net, the cone ring net above the spherical crown net tilts to another direction, avoiding the material from accumulating in the local area of ​​the filter screen. After the solid-liquid separation is completed, the spherical crown metal filter is removed (that is, it is turned upside down. After turning it upside down, the cone ring net and the spherical crown net are no longer under pressure, so the elastic metal wire contracts or the elastic metal wire contracts with the action of the torsion spring, and the plastic film is also folded or wrinkled. When the plastic film is also retracted due to the contraction of the elastic metal wire, the plastic film will not enter the fixed pulley due to the arc-shaped baffle with a smooth curved surface fixed on the wheel axle) to complete the material removal.

[0057] Of course, when the spherical crown net or cone ring net is tilted, the solid material will roll appropriately due to the tilt (the rolling property may not be as good as that of fully processed quartz sand, but it also has a certain rolling property), causing the position of the solid material to change. This is also what is desired. In this way, the solid material will not accumulate in a local position of the filter screen, which can extend the life of the filter screen.

[0058] Example 4: The difference from Example 1 is that Figures 19 to 21As shown, the pickling process is to place the ground solid material in the pickling reactor 14, the acid liquid inlet 15 of the pickling reactor 14 is set at the bottom of the pickling reactor body, and the reactor body is provided with a stirring shaft 16, which passes through the top of the reactor body and is connected to the reduction motor 17. The stirring shaft is provided with stirring blades 18, and each stirring blade 18 is provided below a material carrier 19 fixedly connected to the side wall of the reactor body. The material carrier is inclined and has a plurality of through holes on it for the acid to pass through, and is connected to the acid liquid inlet. An acid inlet pipe is provided with a water pump to spray the acid liquid into the kettle body; an opening 20 is provided on the side wall of the kettle body at the lower end of each loading plate 19 for receiving the pickled quartz sand; an inclined feeding plate 21 is fixedly provided inside the side wall of the kettle body, and a plurality of through holes are also provided on the inclined feeding plate 21 for draining the acid liquid on the pickled quartz sand to the bottom of the inner wall of the kettle body; an opening 22 is provided on the outer wall of the side wall of the kettle body at the lower end of the inclined feeding plate for discharging the quartz sand (the surface of which is basically not contaminated with acid liquid);

[0059] In the existing quartz sand purification reactor, acid is generally poured directly into the reactor for reaction during pickling, and a large amount of acid does not participate in the reaction, resulting in acid waste. In the existing quartz sand purification reactor, the material is directly unloaded after the pickling and purification reaction, so that acid remains on the quartz sand, which will cause corrosion to the workers when touched;

[0060] In addition, existing pickling reactors have the problem of quartz sand backflowing into the acid inlet pipe during acid circulation. Filter cloth is generally used to avoid this problem, but it is extremely wasteful. Since solid materials are discharged from the upper part of the reactor body, while the acid liquid eventually falls to the bottom of the reactor body, the acid liquid and the quartz sand are separated. With this arrangement, the surface of the quartz sand discharged from the pickling process is almost free of acid liquid. Furthermore, since the acid liquid is injected into the reactor body from bottom to top, the acid liquid that does not participate in the reaction can be recycled (or driven upward by the acid injection from the acid liquid inlet to pickle the quartz sand on the carrier plate), greatly reducing acid waste.

[0061] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A process for preparing ultra-high purity amorphous silicon dioxide synthetic quartz sand, characterized in that: The process comprises the following steps: placing amorphous silicon dioxide, a mineralizer and ultrapure water in a reactor for high temperature and high pressure reaction, discharging the reaction product, and simultaneously performing solid-liquid separation, grinding, pickling, cleaning and drying to obtain an ultra-high purity amorphous silicon dioxide synthetic quartz sand product; When unloading, the discharge port of the reactor is opened, and the pressure inside the reactor is used to discharge the liquid in the reactor through the filter at the discharge port of the reactor, thereby achieving solid-liquid separation while unloading; then the filter is removed from the discharge port to take out the solid in the reaction product; The lower end of the reactor is connected to a discharge pipe. The pipe opening of the discharge pipe away from the reactor body is the discharge port. The filter screen at the discharge port is a spherical crown-shaped metal filter screen that protrudes outward. The bottom size of the spherical crown of the spherical crown metal filter screen is larger than the size of the discharge port. The edge of the spherical crown metal filter screen is provided with an outer flange. The inner wall of the discharge pipe near the discharge port is provided with an annular groove that adapts to the outer flange. The spherical crown metal filter consists of a spherical crown net at the bottom and several cone ring nets of gradually increasing size arranged in sequence from bottom to top. The upper edge of the spherical crown net, the lower edge of the top cone ring net and the upper and lower edges of the remaining cone ring nets are fixed with metal rings with a U-shaped cross-section. The upper and lower adjacent metal rings are hinged and every two upper and lower adjacent hinge points are staggered. The upper and lower adjacent metal rings are symmetrical in shape and the openings of the two metal rings are opposite to each other. A fixed pulley is rotatably set in the upper metal ring of the upper and lower adjacent metal rings, and an elastic metal wire is wound on the fixed pulley. One end of the elastic metal wire is fixedly connected to the fixed pulley, and the other end is fixedly connected to the lower metal ring of the upper and lower adjacent metal rings; a plastic film is also provided between the two upper and lower adjacent metal rings, and the upper and lower edges of the plastic film are fixedly connected to the upper metal ring and the lower metal ring respectively.

2. The process for preparing ultra-high purity amorphous silicon dioxide synthetic quartz sand according to claim 1, wherein: Before the unloading process, a process of releasing the pressure bolts at the bottom of the reactor body to relieve the pressure of the reactor body is provided.

3. The process for preparing ultra-high purity amorphous silicon dioxide synthetic quartz sand according to claim 2, wherein: The drying process is to use a dryer to dry the cleaned material or to use the hot air ejected from the pressure bolt in the pressure relief process during the preparation of the next batch of ultra-high purity amorphous silicon dioxide synthetic quartz sand products to dry the cleaned material.

4. The process for preparing ultra-high purity amorphous silicon dioxide synthetic quartz sand according to claim 3, wherein: After the solid-liquid separation process, the spherical crown metal filter is removed and the solid material on the spherical crown metal filter is poured out. Then, the solid material is ground, pickled, and cleaned and then placed in the spherical crown metal filter. The spherical crown metal filter carrying the solid material is then placed on the pressure bolt in the pressure relief process of the next batch of ultra-high purity amorphous silicon dioxide synthetic quartz sand product preparation process for drying.

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