Equipment and method for preparing high-purity quartz sand from fluosilicic acid

Abstract

The invention discloses equipment for preparing high-purity quartz sand from fluosilicic acid. The equipment is composed of an ammoniation kettle and a mechanism for preparing quartz sand from silicon dioxide, and the mechanism for preparing quartz sand from silicon dioxide is composed of a transformation form melting chamber, a sand making chamber, a gas-solid separation chamber and a gas seal discharging screw which are sequentially arranged from top to bottom; and a structure for ensuring the sand making effect is arranged on the transformation form melting chamber. The invention further discloses a method for preparing high-purity quartz sand from fluosilicic acid, the fluosilicic acid is purified and then reacts with liquid ammonia to obtain a mixture of an ammonium fluoride solution and a silica gel solid, and after solid-liquid separation, the silica gel solid is cleaned and dried to obtain high-purity silicon dioxide; heating and melting the high-purity silicon dioxide to convert the amorphous silicon dioxide into a form; and then carrying out two-stage cooling, and carrying out gas-solid separation to obtain a solid, namely the high-purity quartz sand. According to the invention, continuous feeding can be realized, the power consumption is reduced, almost all amorphous silicon dioxide can be completely fused, and the sand making effect is ensured.

Description

Technical Field

[0001] The invention relates to the preparation of finely dispersed silica in neither sol nor gel state, and in particular to a device and method for preparing high-purity quartz sand by using fluorosilicic acid. Background Art

[0002] Patent with publication number CN08675310A: A method for preparing ultrapure quartz sand using fluorosilicic acid as raw material, comprising: reacting fluorosilicic acid solution with alkali to generate fluoride salt solution and silicon dioxide; solid-liquid separation and washing to obtain amorphous silicon dioxide SiO2≥99.99%; adding the amorphous silicon dioxide, mineralizer and ultrapure water into a reactor; heating to dissolve the amorphous silicon dioxide; adding quartz crystal nuclei into the reactor, and then gradually reducing the temperature and pressure in the reactor, and the quartz crystal nuclei grow into quartz crystals; when the quartz crystal particle size is greater than 48μm, reducing the pressure and temperature of the reactor and unloading the material; solid-liquid separation of the material; drying the solid matter, that is, ultrapure quartz sand. It requires many types of raw materials (requiring mineralizers, etc.), which increases the cost of preparing quartz sand.

[0003] In the paper "Technology and Process for Preparing High-Purity Quartz Sand with Fluorosilicic Acid" published by Ying Shengrong in the 4th issue of Volume 20 of Chemical Production and Technology in 2013, it is mentioned that fluosilicic acid reacts with ammonia to generate ammonium fluoride and silicon dioxide... The amount of crystal water carried by silicon dioxide prepared with fluosilicic acid varies greatly under different reaction conditions; although its mass fraction can reach 99.9999%, it is amorphous silicon dioxide and cannot be directly used to make crucibles, filling materials, etc. Therefore, it is also necessary to change its form. By heating amorphous silicon dioxide to a molten state at high temperature and then cooling it in stages, sand-like crystalline quartz sand can be obtained. Its simple reliance on heating and melting makes the sand making efficiency low. In addition, in the quartz sand preparation device in the "Technology and Process for Preparing High-Purity Quartz Sand with Fluorosilicic Acid", after the powdered silicon dioxide is added, it is heated and melted by a plasma power supply. It needs to be completely melted in this nearby position (near the position of the plasma power supply in the transformation melting chamber) to ensure the transformation of the form of all raw materials, which requires higher power consumption.

[0004] It can be seen that the current existing technology for preparing high-purity quartz sand through fluorosilicic acid is basically: after fluorosilicic acid is purified, it reacts with alkali to obtain amorphous silicon dioxide, and then reacts with mineralizers and quartz crystal nuclei at high temperature in a reactor or autoclave (or the amorphous silicon dioxide obtained by the reaction is heated and melted and then cooled in stages to obtain high-purity quartz sand), and then solid-liquid separation and drying are performed to obtain high-purity quartz sand. Either the sand making efficiency is low or the sand making process is complicated. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects in the prior art and provide a high-purity quartz sand preparation device using fluorosilicic acid, which can continuously add materials and reduce power consumption, and can still ensure that almost all amorphous silicon dioxide is completely melted, thereby ensuring the sand making effect.

[0006] To achieve the above purpose, the technical solution of the present invention is to design a high-purity quartz sand preparation equipment with fluorosilicic acid, which is composed of an ammoniation kettle and a quartz sand preparation mechanism of silicon dioxide. The quartz sand preparation mechanism of silicon dioxide is composed of a transition melting chamber, a sand making chamber, a gas-solid separation chamber and a gas-sealed discharge spiral arranged in sequence from top to bottom; a plasma power supply is arranged on the transition melting chamber, and the plasma power supply is located at the middle and upper height of the transition melting chamber; a structure for ensuring the sand making effect is arranged on the transition melting chamber. The sand making effect is guaranteed by improving the transition melting chamber.

[0007] A further technical solution is that the structure includes a baffle set at the outlet of the transformation melting chamber above the sand making chamber, the mesh size of the baffle is smaller than the added silicon dioxide, the outer wall of the transformation melting chamber is fixedly connected with a vibration motor, and the transformation melting chamber is movably connected to the sand making chamber below through a stainless steel bellows. Through the vibration of the vibration motor, the heated and melted silicon dioxide in the transformation melting chamber smoothly passes through the baffle at the outlet and enters the sand making chamber for cooling; the cooled oxygen can be recycled after gas-solid separation.

[0008] A further technical solution is that a cooling water circulation pipeline is also provided in the wall at the middle and lower height of the transformation melting chamber, and a water inlet and a water outlet connected to the cooling water circulation pipeline are respectively provided at the middle and lower height of the transformation melting chamber; a low-temperature oxygen inlet pipe is provided on the sand making chamber; An oxygen inlet pipeline and a protective gas inlet pipeline are also connected above the transformation melting chamber; and a silicon dioxide adding port is arranged at the top of the transformation melting chamber.

[0009] A further technical solution is that two oxygen inlet pipes and / or protective gas inlet pipes are provided, one of which is inclined upward. The oxygen inlet pipe and / or protective gas inlet pipe is inclined upward compared to the horizontal line, so that blockage can be avoided when amorphous silicon dioxide powder is continuously added, and the blockage can be cleared. Since oxygen is sprayed upward, blockage can be avoided if silicon dioxide blockage occurs).

[0010] The technical scheme disclosed in the present invention is a method for preparing high-purity quartz sand from fluorosilicic acid, using the equipment for preparing high-purity quartz sand from fluorosilicic acid, purifying the fluorosilicic acid and reacting it with liquid ammonia in an ammoniation kettle to obtain a mixture of ammonium fluoride solution and silica gel solids, and washing and drying the silica gel solids after solid-liquid separation to obtain high-purity silicon dioxide; then heating and melting the high-purity silicon dioxide obtained by fluorosilicic acid to transform the amorphous silicon dioxide obtained by fluorosilicic acid, and then cooling in two stages and then separating the gas and solid to obtain high-purity quartz sand. The silicon dioxide obtained by the fluorosilicic acid ammoniation method has a high purity, which can reach more than 6N; and the quartz sand obtained by the heating, melting and staged cooling method has high quality and a purity of more than 6N.

[0011] A further technical solution is that in the heating and melting process, there is also a process of accelerating the melting of the heated amorphous silicon dioxide by vibrating or shaking it. The amorphous silicon dioxide obtained by fluosilicic acid is transformed into the desired quartz sand by heating and melting; fewer types of raw materials are required (no mineralizer is required), reducing the cost of preparing quartz sand. Compared with the method of preparing high-purity quartz sand by reacting silicon dioxide and a mineralizer in a reactor, the sand making process is simpler.

[0012] The advantages and beneficial effects of the present invention are: through the vibration of the vibration motor, the heated and molten silicon dioxide in the transformation melting chamber passes smoothly through the baffle at the outlet into the sand making chamber for cooling; after gas-solid separation, the cooled oxygen can be recycled.

[0013] The oxygen inlet pipe and / or the protective gas inlet pipe are tilted upward compared to the horizontal line, which can avoid blockage when the amorphous silica powder is continuously added, and play a role in clearing the blockage. Since the oxygen is sprayed upward, if the silica blockage occurs, the blockage can be avoided).

[0014] The silicon dioxide produced by the fluosilicic acid ammoniation method has high purity, which can reach above 6N. The quartz sand produced by the heating, melting and staged cooling method has high quality and purity which can reach above 6N.

[0015] The amorphous silicon dioxide produced by fluosilicic acid is transformed into the desired quartz sand by heating and melting; fewer types of raw materials are required (no mineralizer is required), reducing the cost of preparing quartz sand. Compared with the method of preparing high-purity quartz sand by reacting silicon dioxide and mineralizer in a reactor, the sand making process is simpler. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of a first embodiment of a device for preparing high-purity quartz sand from fluorosilicic acid according to the present invention; Figure 2 is a schematic diagram of a second embodiment of the present invention; Figure 3Schematic diagram of a transformation morphology melting chamber in a silicon dioxide preparation quartz sand mechanism in Example 3 of the present invention; Figure 4 is a schematic diagram of a fourth embodiment of the present invention; Figure 5 yes Figure 4 Schematic diagram of the middle connection screen and the side wall of the transformation melting chamber adjacent thereto; Figure 6 yes Figure 5 Schematic diagram of the state after being blown by oxygen; Figure 7 is a schematic diagram of Embodiment 5 of the present invention; Figure 8 yes Figure 7 An enlarged schematic diagram of the upper half of ; Fig. 9 It is a schematic diagram of the sixth embodiment of the present invention.

[0017] In the figure: 1. Transformation melting chamber; 2. Sand making chamber; 3. Gas-solid separation chamber; 4. Gas-sealed discharge screw; 5. Plasma power supply; 6. Water inlet; 7. Water outlet; 8. Low-temperature oxygen inlet pipe; 9. Oxygen inlet pipeline; 10. Protective gas inlet pipeline; 11. Silicon dioxide addition port; 12. Blocking net; 13. Vibrating motor; 14. Stainless steel bellows; 15. Quartz crystal core feeding pipe; 16. Branch pipe; 17. Opening and closing valve; 18. Mass flow meter; 19. Network connection; 20. Air connection spoon; 21. Blocking rod; 22. Folding plate; 23. Temperature sensor; 24. Controller; 25. Liquid sand separation net; 26. Throttle valve; 27. Quartz sand outflow pipe. DETAILED DESCRIPTION

[0018] 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.

[0019] Embodiment 1: Figure 1 As shown, the present invention is a high-purity quartz sand preparation device for fluorosilicic acid, which is composed of an ammonia reactor and a quartz sand preparation mechanism of silicon dioxide. The quartz sand preparation mechanism of silicon dioxide is composed of a transition form melting chamber 1, a sand making chamber 2, a gas-solid separation chamber 3 and a gas-sealed discharge spiral 4 arranged in sequence from top to bottom; a plasma power supply 5 is arranged on the transition form melting chamber 1, and the plasma power supply is located at the middle and upper height of the transition form melting chamber; A cooling water circulation pipeline is also provided in the wall at the middle and lower height of the transformation form melting chamber 1, and a water inlet 6 and a water outlet 7 connected to the cooling water circulation pipeline are respectively provided at the middle and lower height of the transformation form melting chamber 1; a low-temperature oxygen inlet pipe 8 is provided on the sand making chamber 2; The upper part of the transformation melting chamber 1 is also connected with an oxygen inlet pipe 9 and a protective gas inlet pipe 10; the top of the transformation melting chamber is provided with a silicon dioxide addition port 11; A baffle 12 is arranged at the outlet of the transformation melting chamber 1 above the sand making chamber 2, and the mesh size of the baffle 12 is smaller than the added silica; a vibration motor 13 is fixedly connected to the outer wall of the transformation melting chamber 1, and the transformation melting chamber 1 is movably connected to the sand making chamber 2 below through a stainless steel bellows 14.

[0020] In the process of heating and melting amorphous silicon dioxide to complete the transformation of silicon dioxide morphology, if the raw materials are added in batches, the efficiency is not high; if the raw materials are added continuously, the existing technology (such as the quartz sand preparation device in the "Technology and Process for Preparing High-Purity Quartz Sand with Fluorosilicic Acid", after the powdered silicon dioxide is added, it is heated and melted by a plasma power supply, and the bottom of the transformation melting chamber is directly connected to the sand making chamber) is difficult to ensure that the amorphous silicon dioxide added to the transformation melting chamber is completely melted and the transformation is completed. If amorphous silicon dioxide is added continuously, if the power of the plasma power supply is low, there will be a lot of amorphous silicon dioxide that cannot be transformed (but cannot guarantee the sand making efficiency, sand making effect and sand making purity requirements), and in order to ensure that all amorphous silicon dioxide is transformed, a larger power of the plasma power supply is required, so the power consumption is large. This problem can be well solved by setting a baffle between the sand making chamber and the transformation melting chamber. In this way, continuous feeding can be achieved, power consumption is reduced, and almost all amorphous silicon dioxide can still be ensured to be completely melted, ensuring the sand making effect.

[0021] There are two oxygen inlet pipes 9 and / or protective gas inlet pipes, one of which is arranged upwardly at an angle; A method for preparing high-purity quartz sand from fluorosilicic acid, using the above-mentioned equipment for preparing high-purity quartz sand from fluorosilicic acid, purifying the fluorosilicic acid and reacting it with liquid ammonia in an ammoniation kettle to obtain a mixture of ammonium fluoride solution and silica gel solids, and after solid-liquid separation, washing and drying the silica gel solids to obtain high-purity silicon dioxide; The high-purity silicon dioxide prepared by fluosilicic acid is then heated and melted to change the amorphous silicon dioxide prepared by fluosilicic acid into a new state, and then cooled in two stages and then separated into gas and solid, and the solid is high-purity quartz sand.

[0022] The heating and melting step is further provided with a step of accelerating the melting of the heated amorphous silicon dioxide by vibrating or shaking it.

[0023] Embodiment 2: The difference from Embodiment 1 is that Figure 2As shown, a quartz crystal nucleus feeding pipe 15 is provided on one side of the sand making chamber 2, and quartz crystal nuclei are added into the sand making chamber to speed up the sand making speed; a branch pipe 16 connected to the sand making chamber 2 is provided at the discharge port of the gas-solid separation chamber 3, and an opening and closing valve 17 is provided on the branch pipe 16, and after quartz sand is produced in the sand making process, part of the quartz sand is introduced into the sand making chamber 2, so as to speed up the sand making speed, improve the sand making efficiency, and reduce the total time required for sand making; A mass flow meter 18 is provided on each of the sand making chambers 2. The mass flow meter 18 of the transformation melting chamber 1 is arranged below the oxygen inlet pipe 9 but above the plasma power supply 5; the mass flow meter 18 of the sand making chamber 2 is arranged near the outlet of the transformation melting chamber; The amount of amorphous silicon dioxide added and the amount of shaped silicon dioxide melted into liquid and leaving the transformation melting chamber 1 can be measured by a mass flow meter; according to the relationship between the mass of shaped silicon dioxide generated after the amorphous silicon dioxide is heated and melted, the amount of liquid outflow can be measured, so that the amount of amorphous silicon dioxide that needs to be added can be obtained; In the process of heating amorphous silicon dioxide to melt at high temperature and then cooling in stages, the speed of quartzization gradually decreases due to the gradual decrease in raw material concentration. The heated and molten silicon dioxide liquid is discharged from the transformation melting chamber (flowing from the mesh opening of the baffle into the sand making chamber below), and an equal amount of amorphous silicon dioxide is added while being discharged to ensure the concentration of the raw materials (which can ensure that the speed of quartzization does not decrease and improve the efficiency of sand making), and then the discharged molten liquid is cooled in stages to obtain sand-like crystalline quartz sand.

[0024] Embodiment 3: The difference from Embodiment 1 is that Figure 3 As shown, a staggered connection screen for receiving a portion of the added silicon dioxide is provided in the transformation morphology melting chamber 1. The connection screen 19 is made of tungsten wire mesh, molybdenum wire mesh or niobium wire mesh. The connection screen is located at the plasma power source 5 and near the upper and lower parts. The connection screen 19 is tilted downward. The provision of several vertically staggered connection nets 19 can separate the added silicon dioxide, avoiding all of them being located in the pipeline of the transformation melting chamber 1 where the plasma power supply 5 is located, which is not conducive to the rapid and complete melting of the added silicon dioxide; while the vertically staggered connection nets 19 disperse the silicon dioxide on the one hand, and due to the inclined setting, in conjunction with the shaking of the transformation melting chamber 1 by the vibration motor 13, once the silicon dioxide melts into liquid, it can immediately flow downward and leave the connection net. This arrangement is conducive to the complete melting of the added silicon dioxide and the rapid melting, thereby improving the efficiency of sand making.

[0025] Embodiment 4: The difference from Embodiment 1 is that Figures 4 to 6As shown, the transformation form melting chamber 1 is fixedly connected to the sand making chamber 2 below, and the structure includes a staggered arrangement of connecting meshes arranged in the transformation form melting chamber 1 for receiving a part of the added silicon dioxide, the connecting mesh 19 is made of tungsten wire mesh, molybdenum wire mesh or niobium wire mesh, and the connecting mesh is located at the plasma power supply 5 and near the upper and lower parts, the connecting mesh 19 is tilted downward, and the connecting mesh 19 is hingedly connected to the inner side wall of the transformation form melting chamber 1, and the movable end of the connecting mesh 19 is integrally connected with an air receiving spoon 20, and the air receiving spoon 20 is arranged facing the oxygen inlet pipe 9 or the protective gas inlet pipe 10. A clearing rod 21 is fixedly connected to the portion of the topmost connection net 9 located inside the transformation form melting chamber 1 facing the silica addition port 11 (the bending direction of the air receiving spoon depends on the position of the air outlet of the oxygen inlet pipe 9 or the protective gas inlet pipe 10. Several more oxygen inlet pipes 9 or protective gas inlet pipes 10 can be provided to ensure that the air receiving spoon at each connection net end faces the air outlet of the oxygen inlet pipe 9 or the protective gas inlet pipe 10; and relatively arranged oxygen inlet pipes 9 or protective gas inlet pipes 10 are provided on the transformation form melting chamber 1).

[0026] The end of the connecting net 19 away from the air receiving spoon 20 is located inside the inner wall of the transformation melting chamber 1 and is fixedly connected to a folding plate 22 to limit the rotation angle of the connecting net (when the folding plate rotates to another vertical position, it is abutted by the inner wall of the transformation melting chamber 1 and cannot continue to rotate).

[0027] After such arrangement, the oxygen or protective gas that needs to be introduced is utilized as power (further reducing power consumption), and (after the air receiving scoop is blown by the introduced oxygen or protective gas) the connecting net 19 is made to shake (specifically, it is rotated up and down around its hinge point at a certain angle), thereby accelerating the heated and molten silica liquid to leave the connecting net. In addition, the shaking of the connecting net is utilized to realize the vertical up and down movement of the unblocking rod 21, thereby preventing the added amorphous silica from being blocked at the silica addition port 11 (indirectly ensuring the sand making effect).

[0028] Embodiment 5: The difference from Embodiment 4 is that Figure 7 , Figure 8 As shown, a mass flow meter 18 arranged on the transformation state melting chamber 1 is also provided below the lowest network connection 19, a temperature sensor 23 and an opening and closing valve are connected to the water outlet 7 on the transformation state melting chamber 1, an opening and closing valve is provided at the water inlet 6 on the transformation state melting chamber 1, the opening and closing valve, the mass flow meter 18 and the temperature sensor 23 are connected to the controller 24 signal, and the controller 24 is located next to the transformation state melting chamber 1.

[0029] When the flow rate detected by the mass flow meter 18 provided on the transformation form melting chamber 1 under the lowest connection network 19 is zero, it means that no heated molten liquid flows down. If the temperature detected by the temperature sensor 23 is close to the temperature of the cooling water (a threshold range is set in advance, if the detected temperature is not much different from the temperature of the injected cooling water, such as ±5% or ±2%), the controller 24 controls the two opening and closing valves to close, stop the cooling water from continuing to be injected into the cooling water circulation pipeline, and also prevent the cooling water retained in the cooling water circulation pipeline from being injected into the warm water recovery tank. When the flow rate detected by the mass flow meter 18 provided on the transformation form melting chamber 1 under the lowest connection network 19 is no longer zero, it means that there is heated molten liquid flowing down again, and the controller 24 opens the two opening and closing valves to continue the circulation of cooling water.

[0030] In view of the fact that the technical solution of the fourth embodiment may exist in the process of heating and melting amorphous silicon dioxide, sometimes there is no molten liquid flowing down but the cooling water continues to flow into the cooling water circulation pipeline, so there is a certain degree of cooling water waste, and the outlet of the cooling water circulation pipeline is generally directly connected to the warm water recovery tank, so that the cooling water is directly injected into the warm water recovery tank; on the one hand, the warm water recovery tank is replaced earlier (or it is not necessary to be so early), on the other hand, the cooling water is wasted, so that the amount of cooling water used increases; accurate cooling is not achieved. After the technical solution of this embodiment is improved, the cooling water is added only when cooling is needed, and the addition of cooling water is stopped when it is not needed, so as to achieve accurate cooling, reduce the amount of cooling water, and avoid the waste of cooling water; and the design of this technical solution is to detect the water temperature at the outlet, so that the two opening and closing valves are not closed until the cooling water circulation pipeline is full of cooling water, so that when the mass flow meter detects the flow again, the cooling water in the wall of the transformation melting chamber 1 is cold when the cooling water circulation is performed again, which can ensure the cooling effect when the cooling cycle is opened again.

[0031] Embodiment 6: The difference from Embodiment 5 is that Fig. 9 As shown (for the convenience of illustration, the gas-solid separation chamber, the gas-sealed discharge screw and the controller are not shown), a liquid sand separation net 25 arranged obliquely is provided at the bottom of the transformation state melting chamber 1 below the baffle 12, and the size of the mesh opening on the liquid sand separation net 25 is smaller than the particle size of the finished product after two-stage cooling, that is, the high-purity quartz sand; a throttle valve 26 is provided at the bottom outlet of the transformation state melting chamber 1 (to control the amount of the heated and molten liquid flowing into the sand making chamber 2 below the transformation state melting chamber 1) (in order to better control the flow rate, the bottom outlet of the transformation state melting chamber 1 can be set to have a smaller cross-sectional size, such as Fig. 9As shown in FIG. 2 , it is an inverted cone-shaped cylinder. An opening penetrating the side wall is provided on the side wall near the bottom of the transformation melting chamber 1. The opening is located above the lowermost end of the liquid sand separation net 25. The opening is connected to the quartz sand outflow pipe 27. The quartz sand outflow pipe 27 is also provided with a throttle valve 26 to control the amount of quartz sand flowing into the sand making chamber 2 below the transformation melting chamber 1. A mass flow meter 18 is provided below the two throttle valves in the sand making chamber 2. The liquid sand separation net 25 is bent and bent upward, which can better guide the quartz sand that has been cooled into solid particles to gather at the quartz sand outflow pipe 27. The mass flow meter and the throttle valve are connected to the controller signal, and the opening of the throttle valve is controlled by the flow information received by the controller.

[0032] After such arrangement, some liquids that have not been completely cooled into quartz sand and solid particles that have been cooled into quartz sand are separated to a certain extent after the amorphous silicon dioxide is heated, melted and cooled. The appropriate proportion of solid-liquid mixing can be determined according to the amount of cooling oxygen introduced into the sand making chamber 2 and the volume of the sand making chamber (the opening of the two throttle valves is adjusted to control the amount of liquid and quartz sand entering the sand making chamber 2), which can ensure a better sand making effect and avoid the problem that too much liquid enters the sand making chamber and exceeds the amount that can be cooled and processed (or if the amount of liquid that has not been cooled into quartz sand is too much, and since only low-temperature oxygen is introduced into the sand making chamber, some of the liquid will not be converted into quartz sand in the end, making the sand making effect poor). Of course, since a small part of the liquid may also enter the quartz sand outflow pipe 27, it is impossible to completely ensure that all the liquid flows into the sand making chamber 2 from the outlet of the transformation form melting chamber 1 on one side of the quartz sand outflow pipe 27, but compared with the fifth embodiment, its liquid sand is separated to a greater extent, and the sand making effect has been greatly improved.

[0033] 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 device for preparing high-purity quartz sand from fluorosilicic acid, characterized in that: It consists of an ammonia reactor and a silica preparation quartz sand mechanism. The silica preparation quartz sand mechanism consists of a transition state melting chamber, a sand making chamber, a gas-solid separation chamber and a gas-sealed discharge spiral which are arranged in sequence from top to bottom. A plasma power supply is arranged on the transition state melting chamber, and the plasma power supply is located at the middle and upper height of the transition state melting chamber. A structure to ensure the sand making effect is arranged on the transition state melting chamber.

2. The device for preparing high-purity quartz sand from fluorosilicic acid according to claim 1, characterized in that: The structure includes a baffle net arranged at the outlet of the transformation melting chamber above the sand making chamber, the mesh size of the baffle net is smaller than the added silica, a vibration motor is fixedly connected to the outer wall of the transformation melting chamber, and the transformation melting chamber is movably connected to the sand making chamber below through a stainless steel bellows.

3. The device for preparing high-purity quartz sand from fluorosilicic acid according to claim 2, characterized in that: A cooling water circulation pipeline is also provided in the wall at the middle and lower height of the transformation form melting chamber, and a water inlet and a water outlet connected to the cooling water circulation pipeline are respectively provided at the middle and lower height of the transformation form melting chamber; a low-temperature oxygen inlet pipe is provided on the sand making chamber; An oxygen inlet pipeline and a protective gas inlet pipeline are also connected above the transformation melting chamber; and a silicon dioxide adding port is arranged at the top of the transformation melting chamber.

4. The device for preparing high-purity quartz sand from fluorosilicic acid according to claim 3, characterized in that: The oxygen inlet pipes and / or the protective gas inlet pipes are provided with two, one of which is arranged obliquely upward.

5. A method for preparing high-purity quartz sand from fluorosilicic acid, characterized in that: The high-purity quartz sand preparation equipment using fluorosilicic acid as claimed in any one of claims 1 to 4 is used, and after the fluorosilicic acid is purified, it is reacted with liquid ammonia in an ammoniation kettle to obtain a mixture of ammonium fluoride solution and silica gel solids, and after solid-liquid separation, the silica gel solids are washed and dried to become high-purity silicon dioxide; the high-purity silicon dioxide prepared by fluorosilicic acid is then heated and melted to transform the amorphous silicon dioxide prepared by fluorosilicic acid, and then two-stage cooling is performed, and the solid after gas-solid separation is high-purity quartz sand.

6. The method for preparing high-purity quartz sand from fluorosilicic acid according to claim 3, characterized in that: The heating and melting step further includes a step of accelerating the melting of the heated amorphous silicon dioxide by vibrating or shaking the heated amorphous silicon dioxide.

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