Preparation process for synthesizing quartz sand from ultra-pure amorphous silicon dioxide

Abstract

The invention discloses a preparation process of ultra-pure amorphous silicon dioxide synthesized quartz sand, which comprises the following process steps in sequence: carrying out high-temperature and high-pressure reaction on amorphous silicon dioxide, a mineralizing agent and ultrapure water, discharging the reaction product, and carrying out solid-liquid separation, grinding, acid pickling and cleaning while discharging to obtain the ultra-pure amorphous silicon dioxide synthesized quartz sand. And drying to obtain the ultra-pure amorphous silicon dioxide synthetic quartz sand product. The pressure in the reaction kettle is utilized, solid-liquid separation is achieved while discharging is conducted, and the cost of independently purchasing a solid-liquid separation device is saved. As the amorphous silicon dioxide is adopted, the purity of the amorphous silicon dioxide is high and controllable, the current situation of lack of high-quality quartz ore in China can be relieved, and the purity of quartz seed crystals input in the crystallization stage is also very high; therefore, the prepared ultra-pure quartz sand is very low in aluminum content, and the total amount of nine impurities such as aluminum, iron, potassium, sodium, calcium, magnesium, titanium, lithium and zirconium is also low.

Description

Technical Field

[0001] The 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 (No. 164 in total) 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 silicon dioxide quartz sand products.

[0003] Non-crystalline silica, also called amorphous silicon dioxide, lacks the ordered arrangement of atoms found in crystalline silica. Its atoms are randomly distributed and do not form a well-defined crystal structure. The most common form of non-crystalline silica is fused quartz, which is formed by rapidly cooling molten silica. Other forms include aerogel, silica gel, and diatomaceous earth. Amorphous silica has a lower density, lower hardness, and lower melting point than crystalline silica.

[0004] At present, ultra-high purity quartz sand generally refers to the specifications of 40~70 mesh or 70~140 mesh, SiO2 purity> 99.9%, Fe2O3 (ppm) <2; ultra-high purity amorphous silicon dioxide synthetic quartz sand is ultra-high purity quartz sand synthesized by amorphous silicon dioxide reaction. The existing methods for preparing ultra-high purity quartz sand include: manual selection of natural ore, and the selected special grade quartz ore is used as the raw material for processing ultra-high purity quartz sand, which is crushed and classified, and then manually selected, and then ground and classified to separate 40~70 mesh and 70~140 mesh two particle sizes as raw materials for processing ultra-high purity quartz sand, and the processed raw materials are first subjected to strong magnetic separation, then flotation, and finally the pollutants on the surface and cracks of the silica sand are removed by chemical treatment to obtain ultra-high purity quartz sand products. Its raw materials are mainly natural minerals, which is a way 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 required requirements, it is more dependent on the high quality of the original ore. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects in the prior art and provide a preparation process for ultra-high purity amorphous silicon dioxide synthetic quartz sand, which utilizes the pressure in the reactor to achieve solid-liquid separation while unloading, thereby eliminating the cost of purchasing a separate solid-liquid separation device. Due to the use of amorphous silicon dioxide, which has high purity and controllable properties, it can alleviate the current situation of my country's lack of high-quality quartz ore, and the purity of the quartz seed crystals invested in the crystallization stage is also very high; therefore, the ultra-high purity quartz sand obtained has a very low aluminum content, and the total amount of nine impurities such as aluminum, iron, potassium, sodium, calcium, magnesium, titanium, lithium, and zirconium is also low.

[0006] To achieve the above purpose, the technical solution of the present invention is to design a preparation process of ultra-high purity amorphous silicon dioxide synthetic quartz sand, which is composed of the following process steps in sequence: amorphous silicon dioxide, mineralizer and ultrapure water are reacted at high temperature and high pressure, the reaction product is unloaded, solid-liquid separation is performed at the same time of unloading, grinding, pickling, cleaning, and drying to obtain ultra-high purity amorphous silicon dioxide synthetic quartz sand products. Solid-liquid separation is performed at the same time of unloading, eliminating the cost of purchasing a separate solid-liquid separation device. Due to the use of amorphous silicon dioxide, which has high purity and controllable properties, it can alleviate the current situation of my country's lack of high-quality quartz ore, and the purity of the quartz seed crystals invested in the crystallization stage is also very high; therefore, the obtained ultra-high purity quartz sand has a very low aluminum content, and the total amount of 9 impurities such as aluminum, iron, potassium, sodium, calcium, magnesium, titanium, lithium, and zirconium is also low.

[0007] A further technical solution is to place amorphous silicon dioxide, mineralizer and ultrapure water in a reactor for high temperature and high pressure reaction; when discharging, the discharge port of the reactor is opened, and the pressure in the reactor is used to discharge the liquid in the reactor through the filter at the discharge port of the reactor, so as to achieve solid-liquid separation during discharging; then the filter is removed from the discharge port to take out the solid in the reaction product. Using the pressure in the reactor for discharge and solid-liquid separation does not require other additional power devices, saving energy consumption and the number of equipment.

[0008] A further technical solution is that before the unloading process, there is a process of releasing the pressure bolts at the bottom of the reactor body to release the pressure of the reactor body. Since it is a pressurized unloading process, the high pressure in the reactor body is first discharged until it is slightly greater than one atmosphere before discharging and solid-liquid separation, ensuring safety.

[0009] A further technical solution is that the drying process uses a dryer to dry the cleaned material or uses the hot air ejected from the pressure bolts 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. Drying the material during pressure relief makes full use of the reactor itself, does not require additional drying equipment, saves energy, eliminates the need for drying equipment, and saves equipment purchase costs.

[0010] A further technical solution is that the lower end of the reactor is connected with a discharge pipe, the pipe opening of the discharge pipe away from the reactor body is the discharge port, the filter at the discharge port is a spherical crown metal filter protruding outward, the bottom size of the spherical crown of the spherical crown metal filter is larger than the size of the discharge port, the edge of the spherical crown metal filter is provided with an outer flange, and the inner wall of the discharge pipe near the discharge port is provided with an annular groove adapted to the outer flange. After such a setting, after the discharge port is opened, the solid and liquid are sprayed out together, but the spherical crown metal filter intercepts the solid material, which plays a role in using the pressure in the reactor to separate the solid and liquid. After the liquid is gone, the spherical crown metal filter is removed to remove the solid.

[0011] A further technical solution is that 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, and then the solid material is ground, pickled, and cleaned before being placed in the spherical crown metal filter. The spherical crown metal filter carrying the solid material is then placed at the pressure bolt in the pressure relief process in the preparation process of the next batch of ultra-high purity amorphous silicon dioxide synthetic quartz sand products for drying. After drying, the spherical crown metal filter can continue to 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 the actual working conditions on site.

[0012] The advantages and beneficial effects of the present invention are: utilizing the pressure inside the reactor to discharge materials and separate solids and liquids, without requiring other additional power devices, thus saving energy consumption and the number of equipment.

[0013] By utilizing the pressure in the reactor, solid-liquid separation is achieved while unloading, eliminating the cost of purchasing a separate solid-liquid separation device. Since amorphous silicon dioxide is used, which has high purity and is controllable, it can alleviate the current situation of my country's lack of high-quality quartz ore. 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 the total amount of nine impurities such as aluminum, iron, potassium, sodium, calcium, magnesium, titanium, lithium, and zirconium is also low.

[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 the pressure relief, making full use of the reactor itself. No additional drying equipment is required, thus saving energy, eliminating the need for drying equipment, and reducing equipment purchase costs.

[0016] With 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, thereby utilizing the pressure inside 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, 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 It is a schematic diagram of a reaction kettle in Example 1 of a process for preparing ultra-high purity amorphous silicon dioxide synthetic quartz sand of the present invention; Figure 2 yes Figure 1 The main view of Figure 3 is a schematic diagram of a reaction kettle in Example 2 of the present invention; Figure 4 yes Figure 3 A partial enlarged schematic diagram of the discharge port at the lower end; Figure 5 yes Figure 4 An enlarged schematic diagram of the mid-sphere crown metal filter; Figure 6 is a schematic diagram of a reaction kettle in Embodiment 3 of the present invention; Figure 7 yes Figure 6 Schematic diagram of the mid-sphere crown metal filter; Figure 8 yes Figure 7 AA section view; Fig. 9 yes Figure 7 Schematic diagram of the decomposition of Fig.10 yes Figure 8 Schematic diagram of the fixed pulley and its adjacent components; Fig.11 yes Fig.10 Schematic diagram of the fixed pulley; Fig.12 yes Figure 7 A partial enlarged schematic diagram of the fixed pulley and its adjacent components; Fig.13 yes Fig.12 Schematic diagram after removing the outer parts of the metal ring and removing the metal ring, elastic wire and plastic film; Fig.14 yes Figure 7 Schematic diagram of the state of the ball crown net after tilting; Fig.15 yes Fig.14 A partial enlarged schematic diagram of the elastic metal wire and its adjacent components; Fig.16 yes Fig.15 A partial enlarged schematic diagram of the plastic film and its surrounding parts; Fig.17 yes Fig.16A side view of the fixed pulley and the arc-shaped baffle; Fig.18 It is a schematic diagram of a spherical crown-shaped metal filter with two hinge points offset and set at a certain angle; Fig.19 is a schematic diagram of a pickling reactor in Embodiment 4 of the present invention; Fig. 20 yes Fig.19 Middle AA section view; Fig.21 yes Fig.19 Schematic diagram of direction B.

[0019] In the figure: 1. discharge port; 2. pressure bolt; 3. spherical crown metal filter; 4. outer flange; 5. spherical crown net; 6. cone 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. reduction motor; 18. stirring blade; 19. loading plate; 20. opening; 21. inclined feed plate; 22. opening. DETAILED DESCRIPTION

[0020] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0021] Embodiment 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 is composed of 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, and an ultra-high purity amorphous silicon dioxide synthetic quartz sand product can be obtained; Amorphous silica, mineralizer and ultrapure water are placed in a reactor for high temperature and high pressure reaction; when 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 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 (it belongs to pressure unloading in nature), so as to achieve solid-liquid separation while unloading; then the filter is removed from the discharge port to take out the solid in the reaction product; By utilizing the pressure in the reactor, solid-liquid separation is achieved while unloading, saving the cost of purchasing a separate solid-liquid separation device; Before the unloading process, there is a process of releasing the pressure bolts 2 at the bottom of the reactor body to relieve the pressure of the reactor body; 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; The high temperature and high pressure reaction comprises: Raw material preparation: Place amorphous silica, mineralizer and ultrapure water into the first reaction kettle; ‌Seal the first reactor‌: Seal the first reactor to ensure that the reaction is carried out under high temperature and high pressure; ‌Heating to a preset temperature‌: The dissolved material in the first reactor is pressed into the second reactor through the high pressure of the first reactor (similar steps before pressing, first release the pressure bolts at the bottom of the first reactor body, and exhaust the pressure of the first reactor to slightly greater than one atmosphere), and quartz seed crystals are put into the second reactor; the temperature is raised to the preset synthesis condition temperature, and the pressure is increased to the preset pressure, and the temperature and pressure are maintained constant for crystal growth; the pressure of the second reactor is less than that of the first reactor; wherein the mineralizer is 95% sodium hydroxide and 25% ammonia water.

[0022] Since amorphous silicon dioxide is used, the purity is high and controllable, which can alleviate the current situation of my country's lack of high-quality quartz ore. 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 the total amount of nine impurities such as aluminum, iron, potassium, sodium, calcium, magnesium, titanium, lithium, and zirconium is also low; 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.

[0023] Embodiment 2: The difference from Embodiment 1 is that Figures 3 to 5 As shown, the lower end of the reactor is connected with a discharge pipe, the pipe opening of the discharge pipe away from the reactor body is a discharge port 1, the filter screen at the discharge port is a spherical crown metal filter screen 3 protruding outward, the size of the bottom 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; The spherical crown metal filter can be made of stainless steel; during installation, 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 on the ring groove and installed. After taking it down (the action of taking it down is opposite to the aforementioned action), pour out the solid material on the spherical crown metal filter 3, and then grind, pickle and clean it, and then directly place it at 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. The material is dried by the hot air sprayed from the pressure bolt during the pressure relief process in the preparation process of the next batch of ultra-high purity amorphous silicon dioxide synthetic quartz sand products.

[0024] Embodiment 3: The difference from Embodiment 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 a plurality of cone ring nets 6 of gradually increasing sizes arranged in sequence from bottom to top. The upper edge of the spherical crown net, the lower edge of the highest cone ring net and the upper and lower edges of the remaining cone ring nets 6 are fixedly provided with a metal ring 7 with a U-shaped cross-section, and 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 set it relative to each other, but to set it 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 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 Fig.18As shown, it avoids 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, 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 each, 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 inside the upper metal ring among 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 among the upper and lower adjacent metal rings; A plastic film 10 is also provided between two adjacent upper and lower metal rings. The upper and lower edges of the plastic film 10 are fixedly connected to the upper metal ring and the lower metal ring respectively; 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 6; The liquid sprayed on the plastic film 10 then continues to flow downward and flows 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 outer surface (i.e., the surface away from the center of the filter screen) of the plastic film.

[0025] 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 material of the torsion spring is 250A53 spring steel; Preferably, three elastic metal wires are arranged. Too few are afraid of not being able to support the lower spherical crown net or conical ring net (especially after solid materials accumulate), and too many are troublesome to install.

[0026] A deformable arc filter is movably arranged at the discharge port. When the pressure is too large or a lot of solids accumulate on the filter, the filter (referring to the ball crown filter) bulges downward and outward (that is, in the direction away from the autoclave body) to avoid clogging of the discharge port due to a lot of solid materials and damage of the filter (referring to the ball crown metal filter 3) when it is under too much pressure. This can reduce the frequency of replacing the filter, and because the filter is rarely replaced, it also saves working hours and labor, because the replacement of the filter requires shutdown, cleaning, ventilation and other processes; avoid the problem that the material is only accumulated locally on the large filter (the local area of ​​the filter is always under pressure) when a large filter is directly used, which can easily reduce the service life of the filter; and because the upper and lower adjacent filter parts (such as adjacent cone ring nets; or between the ball crown net and the cone ring net) are staggered and hinged, when the solid materials in the lowest ball crown net accumulate more and overcome the elastic force of the elastic metal wire (if a torsion spring is also provided, the torque is overcome at the same time), the ball crown net 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 holes of the filter screens at other positions such as the spherical crown screen or the cone ring screen). On the other hand, due to the inclination of the spherical crown screen, the solid materials accumulated subsequently fall directly below the current one (that is, the plastic film pulled out by the spherical crown screen at this time). As the process continues, the solid materials accumulate on the cone ring screen above the spherical crown screen (because the spherical crown screen has previously accumulated a part or has been filled, if it is filled, the subsequent solid materials will gather on the cone ring screen; if it is not filled, part of the materials will fall on the spherical crown screen but also on the filter screen of the tilted spherical crown screen, so it is avoided to accumulate in the local area of ​​the filter screen). When more solid materials reach the elastic force of the elastic metal wire on the metal ring on the cone ring screen above the spherical crown screen, the cone ring screen above the spherical crown screen tilts in another direction to avoid the materials from accumulating in the local area of ​​the filter screen. After the solid-liquid separation is completed, the spherical crown metal filter is taken down (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; and 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 because of the arc-shaped baffle with a smooth curved surface fixed on the wheel axle) to complete the removal of the material.

[0027] 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 we want. In this way, the solid material will not accumulate in a local position of the filter screen, and the life of the filter screen can be extended.

[0028] Embodiment 4: The difference from Embodiment 1 is that Figures 19 to 21As shown, the pickling process is to place the ground solid material in a pickling reactor 14, the acid liquid inlet 15 of the pickling reactor 14 is arranged at the bottom of the kettle body of the pickling reactor, a stirring shaft 16 is arranged in the kettle body, the stirring shaft 16 passes through the top of the kettle 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 plate 19 fixedly connected to the side wall of the kettle body, the material carrier plate is inclined and has a plurality of through holes for the acid liquid to pass through, and is connected to the acid liquid inlet Acid inlet pipe, a water pump is arranged on the acid inlet pipe so that the acid liquid is sprayed into the kettle body; an opening 20 is arranged on the side wall of the kettle body at the lower end of each loading plate 19 for receiving the quartz sand after pickling, an inclined feeding plate 21 is fixedly arranged inside the side wall of the kettle body, and a plurality of through holes are also arranged on the inclined feeding plate 21 for draining the acid liquid on the quartz sand after pickling to the bottom of the side wall of the kettle body, and an opening 22 is arranged 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); In the existing quartz sand purification reactor, acid is generally directly poured 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 staff when they touch it; In addition, when the existing pickling reactor is circulating acid, there is a problem that quartz sand will flow back into the acid inlet pipe. Generally, filter cloth is used to filter to avoid this problem, but it consumes a lot of filter cloth; since the solid material is discharged from the upper part of the kettle body, and the acid liquid finally falls into the bottom of the kettle body, it serves to separate the acid liquid from the quartz sand. After the present application is set up in this way, on the one hand, the surface of the quartz sand discharged from the pickling is almost not contaminated with acid liquid, and since the acid liquid is sprayed into the kettle body from bottom to top, the acid liquid that does not participate in the reaction can continue to be recycled (or driven by the acid injection at the acid liquid inlet to pickle the quartz sand on the carrier plate), which can greatly reduce the waste of acid liquid.

[0029] 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 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 method comprises the following process steps which are carried out in sequence: amorphous silicon dioxide, a mineralizer and ultrapure water are reacted at high temperature and high pressure, the reaction product is discharged, solid-liquid separation is carried out while the product is discharged, and the product is ground, pickled, cleaned and dried to obtain an ultra-high purity amorphous silicon dioxide synthetic quartz sand product.

2. The process for preparing ultra-high purity amorphous silicon dioxide synthetic quartz sand according to claim 1, characterized in that: Amorphous silica, mineralizer and ultrapure water are placed in a reactor for high temperature and high pressure reaction; when unloading, the discharge port of the reactor is opened, and the pressure in the reactor is used to discharge the liquid in the reactor through the filter at the discharge port of the reactor, so as to achieve solid-liquid separation while unloading; then the filter is removed from the discharge port to take out the solid in the reaction product.

3. The process for preparing ultra-high purity amorphous silicon dioxide synthetic quartz sand according to claim 2, characterized in that: 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.

4. The process for preparing ultra-high purity amorphous silicon dioxide synthetic quartz sand according to claim 3, characterized in that: The drying process is to use a dryer to dry the cleaned material or to use the hot air ejected from the pressure bolts 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.

5. The process for preparing ultra-high purity amorphous silicon dioxide synthetic quartz sand according to claim 2 or 4, characterized in that: The lower end of the reactor is connected to a discharge pipe, and the pipe opening of the discharge pipe away from the reactor body is the discharge port. The filter at the discharge port is a spherical crown metal filter protruding outward, and the bottom size of the spherical crown of the spherical crown metal filter is larger than the size of the discharge port. An outer flange is arranged on the edge of the spherical crown metal filter, and an annular groove matching the outer flange is arranged on the inner wall of the discharge pipe close to the discharge port.

6. The process for preparing ultra-high purity amorphous silicon dioxide synthetic quartz sand according to claim 5, characterized in that: 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 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 at the pressure bolt in the pressure relief process in the preparation process of the next batch of ultra-high purity amorphous silicon dioxide synthetic quartz sand products for drying.

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