Vertical quartz sand high temperature purification furnace

Abstract

The utility model belongs to quartz sand high temperature purification technical field relates to a vertical quartz sand high temperature purification furnace, include: feed hopper, stirring shaft, vertical heating section, discharge section, the cylinder of vertical heating section, stirring shaft and helical stirring vane same rotation axis, the clearance between the outer edge of helical stirring vane and the cylinder inner wall of vertical heating section is less than or equal to 20mm;The cylinder of vertical heating section is wrapped with heat preservation layer, and the side of heat preservation layer that is attached to vertical heating section is equipped with heating element;The upper and lower cylinder mouth of vertical heating section is closed, the feed hopper is communicated to the inner chamber of vertical heating section, and the inner chamber of vertical heating section is communicated discharge section;Vertical heating section is equipped with gas supply port, exhaust port;Stirring shaft is connected with driving motor;The utility model can extend the reaction time to 15-25min, and the impurity removal rate of high lattice impurity mineral is improved to more than 90%, and the high / low lattice impurity mineral is adapted, and the vertical furnace gas diffusion and the problem of impurity removal are solved, and the high temperature purification efficiency and quartz sand quality are improved.

Description

Technical Field

[0001] This utility model belongs to the field of high-temperature purification technology of quartz sand, specifically relating to a vertical high-temperature purification furnace for quartz sand. Background Technology

[0002] The preparation of high-purity quartz sand (SiO2 content ≥99.995%) relies on a high-temperature chlorination process, with the core equipment being a high-temperature purification furnace. In existing technologies, high-temperature purification furnaces generally employ an inclined structure. For example, utility model CN22181830U (a tube reactor and high-temperature chlorination treatment device) uses an inclined first tube, improving tube space utilization through multiple reaction zones. However, quartz sand occupies only a small portion of the bottom space of the tube (1 / 5-1 / 3 of the cross-sectional area), making full tube operation impossible. The reaction time is short (5-10 min), and the removal rate of high-lattice impurity minerals (such as Al and Fe impurities >100 ppm) is only 60%-70%. Utility model CN222783929U (a feeding mechanism for a high-temperature purification furnace) only optimizes the feeding synchronization of the inclined high-temperature purification furnace without addressing furnace structure or reaction efficiency improvements. It still relies on the natural flow of the inclined furnace and cannot meet the long-term reaction requirements of high-lattice impurity minerals. Utility Model CN221965273U (A High-Temperature Purification Tube and High-Temperature Purification Device): This device uses a spiral groove on the inner wall of an inclined tube to drive the flow of quartz sand. Although the flow rate can be adjusted, it still operates in a partially full-tube manner, and the spiral groove cannot solve the problem of accumulation and stirring in a vertical furnace. Utility Model CN221619038U (A High-Temperature Chlorine Purification Device for Quartz Sand Drying): This device uses an inclined quartz sand feed pipe, relying on the natural diffusion of chlorine and the rising of hot gas to achieve the reaction. However, it has a low quartz sand filling rate, and reaction products are easily left behind. Furthermore, it does not involve a vertical structure.

[0003] Therefore, existing high-temperature purification equipment for quartz sand has the following drawbacks: all are inclined structures, which cannot achieve full-tube operation of quartz sand; the reaction time is short, and it is only suitable for minerals with low lattice impurities. If the heating section of the inclined furnace is set vertically (vertical structure), although full-tube operation (fill rate ≥95%) and the reaction time can be extended (15-25 min), theoretically improving the removal rate of high lattice impurities, the vertical heating section has new problems: the quartz sand is densely packed with small pores between particles, making it difficult for chlorinated gases (Cl2 density 3.21 g / L, HCl density 1.63 g / L, both much greater than air) to diffuse into the interior, forming "local gas-free zones"; the reaction products (such as FeCl3, AlCl3) have high density and tend to accumulate at the bottom of the packing layer, which cannot be effectively discharged, leading to secondary pollution; quartz sand has no natural flow force, and the existing stirring structure of the inclined furnace (such as tube rotation, spiral groove) cannot be adapted to the vertical full-tube scenario.

[0004] Therefore, a high-temperature quartz sand purification device that combines "full-tube long-time reaction" with "gas diffusion, impurity removal, and stirring optimization" is needed to solve the above-mentioned technical problems. Utility Model Content

[0005] This invention aims to achieve full-pipe operation of quartz sand, extend reaction time, and improve the impurity removal rate of high-lattice impurity minerals; solve the problems of difficult diffusion of chlorine gas and poor discharge of reaction products in vertical furnaces; provide a stirring structure adapted to vertical full-pipe scenarios to ensure sufficient gas-solid contact; and, compared with existing high-temperature purification equipment for quartz sand, overcome its limitation of only being applicable to low-lattice impurity minerals, thus expanding the scope of equipment application.

[0006] This utility model provides the following technical solution: a vertical high-temperature purification furnace for quartz sand, comprising: a feed hopper, a stirring shaft, a vertical heating section, and a discharge section. The inner cavity of the vertical heating section is a cylindrical shape with a vertical rotating shaft. Continuous integral spiral stirring blades are distributed axially on the outer circumference of the stirring shaft. The cylinder, stirring shaft, and spiral stirring blades of the vertical heating section are on the same rotating shaft. The gap between the outer edge of the spiral stirring blades and the inner wall of the cylinder of the vertical heating section is ≤20mm. The vertical heating section is made of high-temperature resistant material. The outer wall of the cylinder of the vertical heating section is surrounded by an insulation layer. Multiple heating elements are evenly distributed on one side of the insulation layer that is in contact with the vertical heating section. The upper and lower openings of the vertical heating section are closed. After passing through the feed section, the feed hopper is connected to the inner cavity of the cylinder of the vertical heating section through the upper opening. The inner cavity of the cylinder of the vertical heating section is connected to the inlet of the discharge section through the lower opening.

[0007] The vertical heating section is equipped with a gas supply port and a gas exhaust port; the inner end of the gas supply port is connected to the bottom of the cylindrical inner cavity of the vertical heating section, and the outer end of the gas supply port is connected to the gas outlet of the gas mixer. The gas inlet of the gas mixer is connected to a chlorine gas source and a nitrogen gas source respectively; the inner end of the exhaust port is connected to the top of the cylindrical inner cavity of the vertical heating section, and the outer end of the exhaust port is connected to the gas inlet of the neutralization tower; the stirring shaft is torque-connected to a drive motor.

[0008] The axis of the vertical heating section is perpendicular to the horizontal plane and is a full-pipe reaction zone of quartz sand (filling rate ≥95%). Heating elements are arranged around the outer wall of the vertical heating section, and an insulation layer is sandwiched between the inner wall and the heating elements. The stirring assembly includes a stirring shaft arranged along the axis of the vertical heating section and spiral stirring blades fixed on the stirring shaft. The top of the stirring shaft passes through the feed section of the vertical furnace body and is connected to the drive motor. The multi-atmosphere gas supply system includes a chlorination gas source, a nitrogen gas source, a gas mixer, and a gas supply port. The input end of the gas mixer is connected to the chlorination gas source and the nitrogen gas source respectively, and the output end is connected to the gas supply port through a pipeline. Nitrogen accounts for 20%-30% (by volume) and chlorination gas accounts for 70%-80% of the mixed gas.

[0009] Preferably, the gap between the outer edge of the spiral stirring blade and the inner wall of the cylindrical section of the vertical heating section is ≤10mm, and the distance between two adjacent blades of the spiral stirring blade along the axial direction is 50-100mm.

[0010] Preferably, a feed valve is provided on the feed channel from the feed hopper to the feed section.

[0011] Preferably, a discharge valve is provided between the lower cylinder opening of the vertical heating section and the inlet of the discharge section.

[0012] More preferably, the discharge valve is a rotary valve. The discharge speed of the rotary valve has an error of ≤5% compared to the feed speed of the feed valve.

[0013] Preferably, the discharge section is cylindrical, and a cooling jacket surrounds its outer circumference. The inner cavity of the cooling jacket is hollow and circulates through a first condenser. A cooling medium circulates between the first condenser and the inner cavity of the cooling jacket. The cooling medium has a flow rate of 8-12 L / min and is used to cool the high-temperature purified quartz sand from 800-1200℃ to 100-200℃.

[0014] Preferably, a second condenser is connected in series on the exhaust channel of the neutralization tower inlet, connected to the outer end of the exhaust port; the neutralization tower contains a 10%-15% NaOH solution. The condenser operates at a temperature of -10 to 0°C, and the distance between the exhaust port and the inlet of the feed hopper is not less than 50 mm. The exhaust port and the gas supply port are offset by 180°.

[0015] Preferably, there are multiple air supply ports, which are evenly distributed at the bottom of the cylindrical cavity of the vertical heating section; the distance between the air supply ports and the inlet of the discharge section is not less than 100mm.

[0016] Preferably, the drive motor includes a stepper motor. The drive motor speed is adjustable (speed adjustment range is 3-10 r / min).

[0017] Preferably, the vertical heating section is made of high-temperature resistant quartz glass; the heating element is made of nickel-chromium resistance wire or induction heating coil; and the insulation layer is made of alumina insulation cotton. The vertical heating section has a height of 1.5-2.0m and an inner diameter of 200-400mm; the heating temperature range of the heating element is 800-1200℃; and the thickness of the insulation layer is 50-80mm.

[0018] The beneficial effects of this utility model are:

[0019] 1. This invention features high high-temperature purification efficiency and a wide range of applicability. The vertical heating section of this invention enables full-pipe operation of quartz sand, extending the reaction time to 15-25 minutes (2-3 times that of existing inclined furnaces). For minerals with Al and Fe lattice impurity content >100ppm, the impurity removal rate is increased to over 90%, far exceeding the 60%-70% impurity removal rate of existing equipment. This invention is suitable for minerals with high / low lattice impurities: high-lattice impurity minerals can be purified using this vertical furnace, while low-lattice impurity minerals can continue to use existing inclined furnaces, solving the problem of the "narrow applicability" of existing equipment.

[0020] 2. In the multi-atmosphere system of this invention, nitrogen acts as a "power carrier," driving chlorine gas to penetrate the quartz sand accumulation layer, increasing gas utilization by 30% (compared to the pure chlorine gas supply of existing equipment); the reaction products of this invention are directionally discharged from the upper exhaust port by nitrogen, reducing the secondary pollution rate to below 5% and avoiding the problem of "product residue"; the central spiral stirring component of this invention achieves gentle stirring in a full-pipe scenario, increasing the gas-solid contact area by 40% and solving the problem of "local gas-free zones" in vertical furnaces. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a vertical high-temperature purification furnace for quartz sand according to the present invention.

[0022] In the diagram, 1. Feed hopper; 2. Feed valve; 3. Feeding section; 4. Drive motor; 5. Stirring shaft; 6. Spiral stirring blades; 7. Vertical heating section; 8. Heating element; 9. Insulation layer; 10. Gas supply port; 11. Gas mixer; 12. Chlorine gas source; 13. Nitrogen gas source; 14. Exhaust port; 15. First condenser; 16. Neutralization tower; 17. Discharge section; 18. Cooling jacket; 19. Discharge valve; 20. Second condenser. Detailed Implementation

[0023] The relevant technologies of this utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0024] like Figure 1 As shown, this embodiment provides a vertical high-temperature purification furnace for quartz sand, including a furnace body assembly, a stirring assembly, a multi-atmosphere gas supply system, a feeding assembly, a discharging assembly, and an exhaust assembly. The specific structure is as follows:

[0025] 1. Furnace body components

[0026] Vertical furnace body: The whole is in the shape of a vertical column, which is connected from top to bottom to feed section 3, vertical heating section 7 and discharge section 17. Among them, vertical heating section 7 is the core reaction area, with its axis perpendicular to the horizontal plane, inner diameter 200-400mm, suitable for full tube filling of quartz sand (filling rate ≥95%), and the material is high temperature resistant quartz glass (resistant to 1200℃); heating element 8 is wrapped around the outer wall of vertical heating section 7, using nickel-chromium resistance heating or induction heating, with a heating temperature range of 800-1200℃ to meet the temperature requirements of chlorination reaction; heat insulation layer 9 is set on the outer layer of vertical heating section 7, using alumina insulation cotton (thickness 50-80mm), with a heat loss rate ≤5% / h.

[0027] 2. Stirring assembly (suitable for vertical full-pipe applications)

[0028] The stirring shaft 5 is set along the axis of the vertical heating section 7. The top of the stirring shaft 5 passes through the feed section 3 and is connected to the drive motor 4. The bottom of the stirring shaft 5 extends to the lower middle part of the vertical heating section 7 (without contacting the discharge section). The material is a special plastic that is resistant to high temperature and corrosion. The spiral stirring blades 6 are fixed on the stirring shaft 5. The gap between the diameter of the spiral stirring blades 6 and the inner diameter of the vertical heating section is ≤10mm (to ensure that the tube is fully covered with quartz sand). The spacing between adjacent blades of the spiral stirring blades 6 is 50-100mm (to avoid excessive turning and empty tube). Speed ​​control: The drive motor 4 is a stepper motor with adjustable speed (3-10r / min) to achieve "gentle stirring", break the compactness of the quartz sand (increase the porosity to 15%-20%), and maintain the full tube state.

[0029] 3. Multi-atmosphere gas supply system (solves the problems of gas diffusion and impurity removal)

[0030] Gas source components: including chlorine gas source 12 (Cl2 or HCl cylinder) and nitrogen gas source 13 (purity ≥99.99%), both of which are precisely controlled by flow meters; the gas mixer 11 is a static mixer, with the input end connected to the chlorine gas source 12 and the nitrogen gas source 13, and the output end connected to the gas supply port 10 at the bottom of the vertical heating section 7 through a pipeline; the mixing ratio is 20%-30% nitrogen (volume ratio) and 70%-80% chlorine gas (nitrogen density 0.81g / L, which can drive the high-density chlorine gas to diffuse upwards and simultaneously push the reaction products out); there are 3-4 gas supply ports 10, which are evenly distributed circumferentially along the bottom of the vertical heating section (100-200mm away from the discharge section), with a diameter of 10-15mm, to ensure that the mixed gas diffuses evenly along the furnace wall to the quartz sand accumulation layer.

[0031] 4. Feeding assembly

[0032] Feed hopper 1 is located at the top of the vertical furnace body, with a volume of 0.5-1m³. 3It is used to store quartz sand raw materials; the feed valve 2 is an electric gate valve, located between the feed hopper 1 and the feed section 3, and the feed speed (50-100kg / h) is adjusted by the flow controller to ensure that the vertical heating section 7 is always full.

[0033] 5. Discharge assembly

[0034] The discharge valve 19 is located at the bottom of the vertical furnace body and adopts a star-shaped discharge valve (which has both sealing and discharge functions to prevent chlorine leakage). The discharge speed is matched with the feeding speed (error ≤ 5%). The cooling jacket 18 is fitted on the outer wall of the discharge section 17 and is filled with cooling water (flow rate 8-12L / min). The cooling water flows to the first condenser 15. The cooling jacket 18 cools the high-temperature purified quartz sand from 800-1200℃ to 100-200℃ for subsequent processing.

[0035] 6. Exhaust system (for directional discharge of reaction products)

[0036] The exhaust port 14 is located on the upper side wall of the vertical furnace (50-100mm away from the feed section), and the reaction products are discharged by nitrogen. The tail gas treatment device includes a second condenser 20 (temperature -10-0℃, condensing and recovering metal chlorides) and a neutralization tower 16 (containing 10-15wt% NaOH solution to absorb residual Cl2 / HCl) connected in series to avoid tail gas pollution.

[0037] Example

[0038] The parameter settings for the vertical high-temperature quartz sand purification furnace component in this embodiment are as follows:

[0039] Furnace body components: The vertical heating section 7 has a height of 1.8m and an inner diameter of 300mm, and is made of high-temperature resistant quartz glass; the heating element 8 is a 6kW nickel-chromium resistance wire with a heating temperature of 1000℃; the insulation layer is 50mm thick alumina insulation cotton with a heat loss rate of ≤4% / h.

[0040] Stirring components: The stirring shaft 5 has a diameter of 20mm and a length of 1.6m (special plastic); the spiral stirring blades 6 have a diameter of 290mm and a spacing of 80mm (special plastic); the drive motor 4 is a 10N·m stepper motor with a speed of 5r / min.

[0041] Multi-atmosphere gas supply system: chlorine gas (Cl2) flow rate 80L / min, nitrogen gas flow rate 20L / min (mixing ratio 20% N2 + 80% Cl2); gas supply port 10 has 4 ports (10mm in diameter, 150mm away from the discharge section).

[0042] Feed / discharge assembly: Feed hopper 1, volume 0.8m³ 3The feeding speed is 80 kg / h; the discharge valve 19 is a star-shaped discharge valve (discharge speed 78-82 kg / h); the cooling water flow rate of the cooling jacket 18 is 10 L / min, and the discharge temperature is 150℃.

[0043] Exhaust assembly: exhaust port 14 has a diameter of 20 mm (80 mm from the feed section); the second condenser 20 has a temperature of -5℃, and the NaOH concentration in the neutralization tower 16 is 12%.

[0044] The working process of the vertical high-temperature quartz sand purification furnace in this embodiment is as follows:

[0045] Preheating and feeding: Start heating element 8 to raise the temperature of vertical heating section 7 to 1000℃ and keep it at that temperature; open feed valve 2, and quartz sand enters vertical heating section 7 from feed hopper 1. After confirming that the tube is full through the observation window on the side wall of the furnace, stabilize the feeding speed to 80kg / h.

[0046] Stirring and gas supply: Start the stirring motor (speed 5r / min) and at the same time turn on the multi-atmosphere gas supply system. The mixed gas (20% N2 + 80% Cl2) is introduced from the gas supply port 10. The nitrogen gas carries the Cl2 upward diffusion, penetrates the quartz sand accumulation layer, and reacts with impurities (Al2O3, Fe2O3) to generate FeCl3 and AlCl3.

[0047] Reaction and Impurity Removal: Quartz sand is kept in the vertical heating section 7 for 20 minutes. The reaction products are pushed by nitrogen and enter the tail gas treatment device—the second condenser 20—from the exhaust port 14 to condense and recover metal chlorides. The residual Cl2 is absorbed by the neutralization tower 16 and then discharged.

[0048] Discharge and circulation: Open discharge valve 19, and the high-temperature purified quartz sand is discharged after being cooled to 150°C by the cooling jacket; continuously replenish the feed to maintain the full pipe state and achieve continuous high-temperature purification.

[0049] This embodiment verifies the effectiveness of the vertical high-temperature quartz sand purification furnace:

[0050] After treatment of quartz sand with Al and Fe lattice impurities of 150 ppm: after high-temperature purification, the impurity content is Al≤10 ppm, Fe≤1 ppm, and the impurity removal rate is 93.3%; the chlorine utilization rate is 85%; and the secondary pollution rate is <3% (no obvious reaction product residue).

[0051] In summary, this invention can extend the reaction time to 15-25 minutes, increase the impurity removal rate of high-lattice impurity minerals to over 90%, is suitable for both high and low-lattice impurity minerals, and simultaneously solves the problems of gas diffusion and impurity removal in vertical furnaces, thereby improving high-temperature purification efficiency and quartz sand quality.

[0052] It should be emphasized that the above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model in any way. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present utility model shall still fall within the scope of the technical solution of the present utility model.

Claims

1. A vertical high-temperature purification furnace for quartz sand, characterized in that, include: Feed hopper (1), stirring shaft (5), vertical heating section (7), discharge section (17), the inner cavity of the vertical heating section (7) is a cylindrical shape with the rotating shaft vertical, and the outer circumference of the stirring shaft (5) is provided with continuous integral spiral winding spiral stirring blades (6) distributed along the axial direction. The cylinder of the vertical heating section (7), the stirring shaft (5), and the spiral stirring blade (6) are on the same rotation axis, and the gap between the outer edge of the spiral stirring blade (6) and the inner wall of the cylinder of the vertical heating section (7) is ≤20mm. The vertical heating section (7) is made of high temperature resistant material. The outer wall of the cylinder of the vertical heating section (7) is wrapped with a heat insulation layer (9). Multiple heating elements (8) are evenly distributed on one side of the heat insulation layer (9) that is in contact with the vertical heating section (7). The upper and lower cylinder openings of the vertical heating section (7) are closed. The feed hopper (1) passes through the feed section (3) and then is connected to the inner cylinder of the vertical heating section (7) via the upper cylinder opening. The inner cylinder of the vertical heating section (7) is connected to the inlet of the discharge section (17) via the lower cylinder opening. The vertical heating section (7) is provided with a gas supply port (10) and an exhaust port (14); the inner end of the gas supply port (10) is connected to the bottom of the cylindrical inner cavity of the vertical heating section (7), and the outer end of the gas supply port (10) is connected to the outlet of the gas mixer (11). The inlet of the gas mixer (11) is connected to a chlorine gas source (12) and a nitrogen gas source (13) respectively; the inner end of the exhaust port (14) is connected to the top of the cylindrical inner cavity of the vertical heating section (7), and the outer end of the exhaust port (14) is connected to the inlet of the neutralization tower (16); The stirring shaft (5) is torque-connected to the drive motor (4).

2. The vertical high-temperature purification furnace for quartz sand according to claim 1, characterized in that, The gap between the outer edge of the spiral stirring blade (6) and the inner wall of the cylindrical section (7) is ≤10mm, and the distance between two adjacent blades of the spiral stirring blade (6) along the axial direction is 50-100mm.

3. A vertical high-temperature quartz sand purification furnace according to claim 1, characterized in that, A feed valve (2) is provided on the feed channel from the feed hopper (1) to the feed section (3).

4. A vertical high-temperature quartz sand purification furnace according to claim 1, characterized in that, A discharge valve (19) is provided between the lower cylinder opening of the vertical heating section (7) and the inlet of the discharge section (17).

5. A vertical high-temperature purification furnace for quartz sand according to claim 4, characterized in that, The discharge valve (19) is a star-shaped discharge valve.

6. A vertical high-temperature quartz sand purification furnace according to claim 1, characterized in that, The discharge section (17) is cylindrical, and a cooling jacket (18) is wrapped around the outer circumference of the discharge section (17). The inner cavity of the cooling jacket (18) is hollow, and the inner cavity of the cooling jacket (18) is circulatedly connected to the first condenser (15). A cooling medium circulates between the first condenser (15) and the inner cavity of the cooling jacket (18).

7. A vertical high-temperature purification furnace for quartz sand according to claim 1, characterized in that, The outer end of the exhaust port (14) is connected to the exhaust channel of the inlet of the neutralization tower (16) and a second condenser (20) is connected in series; the neutralization tower (16) contains a NaOH solution with a concentration of 10%-15%.

8. A vertical high-temperature quartz sand purification furnace according to claim 1, characterized in that, The air supply ports (10) are provided in multiple ways and are evenly distributed at the bottom of the cylindrical inner cavity of the vertical heating section (7).

9. A vertical high-temperature purification furnace for quartz sand according to claim 1, characterized in that, The drive motor (4) includes a stepper motor.

10. A vertical high-temperature quartz sand purification furnace according to claim 1, characterized in that, The vertical heating section (7) is made of high-temperature resistant quartz glass; the heating element (8) is made of nickel-chromium resistance wire or induction heating coil; and the insulation layer (9) is made of alumina insulation cotton.

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