Silicon dioxide calcining device and method with dynamic pressure-stabilizing inert gas protection

Abstract

The invention relates to a calcining device in a silicon dioxide post-treatment production process, in particular to a silicon dioxide calcining device and method with dynamic pressure-stabilizing inert gas protection, and the calcining device comprises a rotary calcining device, a dynamic pressure-stabilizing adjusting device, an inert gas protection device and a vacuumizing mechanism, the rotary calcining device comprises a calcining cylinder driven by a driving mechanism to rotate, the left end and the right end of the calcining cylinder are each provided with a heat insulation filtering structure, extension pipes are fixed to the heat insulation filtering structures, the outer side ends of the extension pipes are detachably connected with sealing covers, and the dynamic pressure stabilizing adjusting device is arranged in the extension pipe on one side. The device can effectively reduce the damage of internal pores of silicon dioxide powder particles in the calcining process, and ensures the balanced distribution probability of dredging pore diameters.

Description

Technical Field

[0001] The invention relates to a calcining device in a silicon dioxide post-processing production process, and in particular to a silicon dioxide calcining device and method with dynamic pressure-stabilizing inert gas protection. Background Art

[0002] The chemical synthesis method produces silica powder. Through high-temperature calcination, the hydroxyl groups (-OH) on the surface and inside of silica undergo dehydration reactions, thereby forming stable Si-O-Si bonds, which can effectively improve the purity and stability of the product. However, the existing calcination equipment is atmospheric pressure or vacuum, and the suction force generated by the vacuum negative pressure does not exceed 0.1MPa. Atmospheric pressure or vacuum calcination is not ideal for effectively clearing the internal pores of silica powder particles and achieving a balanced distribution of pore sizes, resulting in energy waste and a high defective rate.

[0003] To this end, inventing a calcination device that can effectively clear the internal pores of silica powder particles and achieve a balanced distribution of pore sizes is of great significance for improving the quality of silica products, enhancing the industry's production level, reducing consumption and carbon emissions, and achieving sustainable development. Summary of the invention

[0004] The object of the present invention is to provide a silicon dioxide calcining device and method with dynamic pressure-stabilized inert gas protection, which can effectively reduce the damage of the internal pores of silicon dioxide powder particles during the calcination process and ensure the probability of balanced distribution of dredged pore sizes.

[0005] The technical solution of the present invention is: a silicon dioxide calcining device with dynamic pressure-stabilizing inert gas protection, including a rotary calcining device, a dynamic pressure-stabilizing adjustment device, an inert gas protection device and a vacuum pumping mechanism, the rotary calcining device includes a calcining cylinder driven to rotate by a driving mechanism, and the left and right ends of the calcining cylinder are provided with heat insulation and filtering structures, and the outer ends of the epitaxial tubes with detachable sealing covers are fixed on the heat insulation and filtering structures, and the dynamic pressure-stabilizing adjustment device is arranged in the epitaxial tube on one side.

[0006] Furthermore, the dynamic pressure stabilization adjustment device includes a hollow piston column arranged in the left outer tube, the outer circular surface of the hollow piston column contacts the inner diameter surface of the left outer tube to form a mirror dynamic seal, and a telescopic spring is installed between the left end of the hollow piston column and the left sealing cover.

[0007] Furthermore, a ventilation pipe is installed axially in the center of the hollow piston column, and the right end of the ventilation pipe is connected to the outlet arranged on the right side of the hollow piston column through the piston column micro-solenoid valve, and the left end of the ventilation pipe passes through the left side of the hollow piston column and the sealing cover on the left side in turn to be connected to the air intake micro-solenoid valve, and the ventilation pipe is slidably matched with the sealing cover on the left side.

[0008] Furthermore, the inert gas protection device comprises an inert gas bottle, the outlet of the inert gas bottle is detachably connected to the air intake micro solenoid valve via a pressure reducing valve, and a pressure sensor is installed between the pressure reducing valve and the air intake micro solenoid valve.

[0009] Furthermore, the vacuum pumping mechanism includes a vacuum pump, and an input end of the vacuum pump is connected to an air outlet micro solenoid valve installed on the sealing cover on the right side.

[0010] Furthermore, the thermal insulation filtering structure comprises short thermal insulation tubes fixed on the left and right ends of the calcining cylinder, cylindrical thermal insulation filtering blocks are installed in the short thermal insulation tubes, and the extension tube is fixed on the outer end of the short thermal insulation tubes.

[0011] Furthermore, a circular electric heating block matching the circumference of the calcining tube is tightly mounted on the outer circumferential surface of the calcining tube, and a heat-insulating layer is mounted on the outer circumferential surface of the circular electric heating block.

[0012] Furthermore, a wireless temperature sensor is installed outside the thermal insulation layer, and the probe sequentially passes through the thermal insulation layer, the annular electric heating block and is in close contact with the outer wall of the calcination tube.

[0013] Furthermore, the sealing covers are spiral sealing covers and are threadedly connected to the outer ends of the corresponding extension tubes. Transmission gears are installed on the outer circumferences of the extension tubes, and the transmission gears are rotated with the driving mechanism.

[0014] A method for calcining silicon dioxide with dynamic pressure-stabilizing inert gas protection, comprising a silicon dioxide calcining device with dynamic pressure-stabilizing inert gas protection, comprising the following steps: 1) Pre-install a telescopic spring with appropriate telescopic force according to the required pressure of calcined silica; 2) Remove the sealing cover on the right side of the rotary calcining device and take out the cylindrical heat-insulating filter block in the heat-insulating filter structure on the right side of the calcining cylinder; 3) Measure and load the silica powder to be calcined into the calcination cylinder, and reinstall the cylindrical insulation filter block and sealing cover on the right side in sequence; 4) Connect the inert gas protection device to the left sealing cover and connect the vacuum device to the right sealing cover; 5) Open the air inlet micro solenoid valve, piston column micro solenoid valve, and air outlet micro solenoid valve in sequence; 6) Turn on the vacuum pump to evacuate the above connecting pipes, pipe fittings and the inside of the rotary calcining device; 7) When the vacuum setting value is reached, close the outlet micro solenoid valve and vacuum pump in sequence, and remove the external pipeline connected to the right side of the rotary calcining device; 8) Open the main valve on the inert gas bottle, open the pressure reducing valve, and fill the high-purity nitrogen into the calcining cylinder through the pressure reducing valve, the air inlet micro solenoid valve, and the piston column micro solenoid valve; 9) When the pressure reaches the set value, close the piston column micro solenoid valve, the air inlet micro solenoid valve, the pressure reducing valve, and the main valve on the inert gas bottle in sequence, stop injecting high-purity nitrogen, and remove the external pipeline connected to the left side of the rotary calcining device; 10) Turn on the driving mechanism and heat the calcining cylinder to achieve uniform rotation, heating and calcination of the silicon dioxide in the calcining cylinder; when the set calcination temperature is reached, maintain the set temperature for calcination; 11) When the pressure in the calcining cylinder exceeds the set telescopic spring force due to heating or gas escape from the silica powder, the hollow piston column moves toward the left extension tube port, and vice versa, always maintaining stable calcination within the set pressure range; 12) When the calcination time is reached, the heating and driving mechanisms of the calcination cylinder are turned off in sequence; 13) When the temperature drops to room temperature, open the outlet micro solenoid valve on the right side of the rotary calcining device to release the pressure in the rotary calcining device; 14) Unscrew the sealing cover on the right side of the rotary calcining device and take out the qualified calcined silicon dioxide; 15) Clean the inside of the calcination cylinder, reinstall the cylindrical insulation filter block and the sealing cover on the right, close the air outlet micro solenoid valve on the right, and prepare for the next calcination cycle.

[0015] Compared with the prior art, the present invention has the following advantages: 1. By designing a protective calcining device with adjustable and stable inert gas pressure when the pressure exceeds 0.1MPa, the damage of the internal pores of the silica powder particles during the calcination process can be effectively reduced, the internal pores of the silica powder particles can be dredged, and the probability of balanced distribution of the dredged pore size can be ensured, thus overcoming the shortcomings of the existing post-processing calcining equipment for silica production, and playing an important role in improving the quality of silica products and saving energy and reducing consumption.

[0016] 2. The device and calcination method are of great significance for improving the quality of silicon dioxide products, enhancing the production level of the industry, reducing consumption and carbon emissions, and achieving sustainable development.

[0017] 3. The device uses a mirrored extension tube on the inner wall of the calcining cylinder and is equipped with a hollow piston column that can move back and forth. It can balance the pressure in the calcining cylinder caused by heating or gas escape from the silica powder, as well as the pressure changes during the calcining process.

[0018] 4. The device can fill external inert gas into the heating section of the calcining cylinder through a hollow dynamic piston column, a vent pipe installed in the central axial direction of the piston column, and a piston column micro solenoid valve.

[0019] 5. The device uses a dynamic hollow piston column with a replaceable telescopic spring to adjust the pressure change setting in the calcining cylinder within a certain range. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a working diagram of the silicon dioxide calcining device with dynamic pressure-stabilized inert gas protection of the present invention; Figure 2 This is a diagram showing the extension state of the telescopic spring of the rotary calcining device of the present invention under dynamic pressure stabilization adjustment; Figure 3 This is a working diagram of the rotary calcining device of the present invention, in which the telescopic spring is dynamically adjusted to be compressed due to heating and the escape of gas inside the silicon dioxide powder; Figure 4 It is an enlarged view of the heat insulation filtering structure of the present invention; Figure 5 For the present invention Figure 3 AA section view; Figure 6 For the present invention Figure 3 BB cross-sectional view; Figure 7 It is a control principle block diagram of the present invention; In the figure: 1-intake micro solenoid valve; 2-sealing cover on the left; 3-telescopic spring; 4-transmission gear; 5-extension tube on the left; 6-ventilation pipe; 7-hollow piston column; 8-left insulation short tube; 9-calcination cylinder; 10-circular electric heating block; 11-insulation layer; 12-wireless temperature sensor; 13-right insulation short tube; 14-extension tube on the right; 15-sealing cover on the right; 16-exhaust micro solenoid valve; 17-piston column micro solenoid valve; 18-cylindrical insulation filter block; 19-silicon dioxide powder; 20-driving mechanism; 21-high-pressure and high-purity nitrogen bottle; 22-main valve; 23-pressure reducing valve; 24-pressure sensor; 25-vacuum pump. DETAILED DESCRIPTION

[0021] In order to make the above features and advantages of the present invention more easily understood, embodiments are given below with reference to the accompanying drawings for detailed description, but the present invention is not limited thereto.

[0022] refer to Figures 1 to 7 A silicon dioxide calcining device with dynamic pressure-stabilizing inert gas protection comprises a rotary calcining device, a dynamic pressure-stabilizing adjustment device, an inert gas protection device and a vacuum pumping mechanism, wherein the rotary calcining device comprises a calcining tube 9 driven to rotate by a driving mechanism 20, and both left and right ends of the calcining tube 9 are provided with heat-insulating filtering structures, and an epitaxial tube with a sealing cover detachably connected to the outer end thereof is fixed on the heat-insulating filtering structure, the dynamic pressure-stabilizing adjustment device is arranged in the epitaxial tube 5 on the left, and the vacuum pumping mechanism is connected to the sealing cover on the right.

[0023] In this embodiment, the dynamic pressure regulating device includes a hollow piston column 7 which is arranged in the left epitaxial tube 5 and is made of 310S stainless steel. The outer circumferential surface of the hollow piston column 7 contacts the inner diameter surface of the left epitaxial tube 2 to form a mirror dynamic seal. A telescopic spring 3 is installed between the left end of the hollow piston column 7 and the left sealing cover 2. When the pressure in the calcining cylinder 9 increases due to heating or the internal gas of the silica powder escaping, the hollow piston column 7 moves toward the left side of the epitaxial tube 5 due to the expansion pressure, and vice versa. The hollow piston column 7 plays a role in stabilizing the internal pressure of the calcining cylinder 9, and the telescopic force of the hollow piston column 7 is adjusted by its matching telescopic spring 3. The different pressure settings inside the rotary calcining device are adjusted by replacing the telescopic spring 3.

[0024] In this embodiment, a ventilation pipe 6 is axially installed in the center of the hollow piston column 7. The right end of the ventilation pipe 6 is connected to the air outlet arranged on the right side of the hollow piston column 9 through the piston column micro-solenoid valve 17. The left end of the ventilation pipe 6 passes through the left side of the hollow piston column 7 and the sealing cover 2 on the left side in turn and is connected to the air intake micro-solenoid valve 1. The ventilation pipe 6 and the sealing cover 2 on the left side are sealed and slidably matched to facilitate the movement of the hollow piston column 7.

[0025] In this embodiment, the inert gas protection device includes an inert gas bottle, which is a high-pressure high-purity nitrogen bottle 21, and high-purity nitrogen is filled in the high-pressure high-purity nitrogen bottle 21. The outlet of the high-pressure high-purity nitrogen bottle 21 is equipped with a main valve 22 and is detachably connected to the air intake micro-solenoid valve 1 through a pressure reducing valve 23. The high-purity nitrogen in the high-pressure high-purity nitrogen bottle 21 is filled into the calcining cylinder 9 through the pressure reducing valve 23, the air intake micro-solenoid valve 1, and the piston column micro-solenoid valve 17, and reaches the set pressure, and the piston column micro-solenoid valve 17 and the air intake micro-solenoid valve 1 are closed.

[0026] In this embodiment, a pressure sensor 24 is installed between the pressure reducing valve 23 and the air intake micro solenoid valve 1 , so that the pressure input into the calcining cylinder 9 is detected by the pressure sensor 24 .

[0027] In another embodiment, the inert gas may be the high-purity nitrogen described above, or may be other inert gases such as argon and helium used in other protective calcining processes.

[0028] In this embodiment, the vacuum pumping mechanism includes a vacuum pump 25, the input end of the vacuum pump 25 is connected to the air outlet micro solenoid valve 16 installed on the right side sealing cover 15, and the right side sealing cover 15 is provided with an air outlet hole connected to the air outlet micro solenoid valve 16.

[0029] In this embodiment, the heat-insulating filter structure includes short heat-insulating tubes fixed on the left and right ends of the calcining tube, namely, the left short heat-insulating tube 8 and the right short heat-insulating tube 13. The left short heat-insulating tube 8 and the right short heat-insulating tube 13 are both installed with cylindrical heat-insulating filter blocks 18. The left extension tube 5 is fixed to the left end of the left short heat-insulating tube 8, and the right extension tube 5 is fixed to the right end of the right short heat-insulating tube 8. The fine pores inside the cylindrical heat-insulating filter block 18 can prevent the silica powder from overflowing to both sides during the calcining process, but allow airflow to pass through. The left short heat-insulating tube 8 and the right short heat-insulating tube 13 are both made of poor heat-conducting materials. The silica powder is loaded into the calcining tube 9 for calcining. The short heat-insulating tubes and the cylindrical heat-insulating filter blocks 18 on both sides of the calcining tube 9 can effectively reduce the heat transfer at both ends of the rotating calcining tube 9.

[0030] In this embodiment, a circular electric heating block 10 matching its circumference is tightly installed on the outer circular surface of the calcination tube 9. The circular electric heating block 10 may be composed of two or more arc-shaped point heating blocks. An insulation layer 11 is installed on the outer circular surface of the circular electric heating block 10.

[0031] In this embodiment, the calcining tube 9, the epitaxial tube 5 on the left, and the epitaxial tube 14 on the right are all made by pressing high-temperature resistant high-quality thick-walled 310S stainless steel plates.

[0032] In this embodiment, a wireless temperature sensor 12 is installed outside the insulation layer 11 , and the probe sequentially passes through the insulation layer 11 , the annular electric heating block 10 and is in close contact with the outer wall of the calcination tube 9 , so as to measure the temperature of the calcination tube 9 .

[0033] In this embodiment, the sealing cover 2 on the left and the sealing cover 15 on the right are spiral sealing covers and are threadedly connected to the outer ends of the corresponding extension tubes. The hollow piston column 7 can be taken out by opening the sealing cover 2 on the left, and the silicon dioxide powder can be loaded or discharged by opening the sealing cover 15 on the right.

[0034] In this embodiment, transmission gears 4 are symmetrically installed on the outer circumferences of the left epitaxial tube 5 and the right epitaxial tube 14. The driving mechanism is a rotary driving mechanism, and the transmission gears and the driving mechanism perform rotational transmission, thereby driving the calcining tube 9 to rotate.

[0035] In this embodiment, a control module is also provided, and the control module is pre-programmed with: rotary calcination cylinder temperature setting, filling pressure setting, drive mechanism speed setting and automatic work control program, etc. The input end of the control module is electrically connected to the output end of the wireless temperature sensor and the pressure sensor, respectively, and the output end of the control module is electrically connected to the input end of the annular electric heating block 10, the air intake micro solenoid valve 1, the piston column micro solenoid valve 17, the air outlet micro solenoid valve 16, the vacuum pump 25, the drive mechanism 20, etc.

[0036] A method for calcining silicon dioxide with dynamic pressure-stabilizing inert gas protection, comprising a silicon dioxide calcining device with dynamic pressure-stabilizing inert gas protection, comprising the following steps: 1) Pre-install a telescopic spring with appropriate telescopic force according to the required pressure of calcined silica; 2) Remove the sealing cover 15 on the right side of the rotary calcining device and take out the cylindrical heat-insulating filter block 18 on the right side of the calcining cylinder 9; 3) Measure and load the silicon dioxide powder to be calcined into the calcination cylinder, and then reinstall the cylindrical heat-insulating filter block 18 and the sealing cover 15 on the right side; 4) Connect the left external pipeline between the high-pressure high-purity nitrogen bottle 21, the pressure reducing valve 23 and the air inlet micro solenoid valve 1 of the rotary calcining device; connect the right external pipeline between the air outlet micro solenoid valve 16 on the right side of the rotary calcining device and the vacuum pump 25; 5) Open the air inlet micro solenoid valve 1, the piston rod micro solenoid valve 17, and the air outlet micro solenoid valve 16 in sequence; 6) Turn on the vacuum pump 25 to evacuate the above connecting pipes, pipe fittings and the inside of the rotary calcining device; 7) When the vacuum setting value is reached, the outlet micro solenoid valve 16 and the vacuum pump 17 are closed in sequence, and the external pipeline connected to the right side of the rotary calcining device is removed; 8) Open the main valve 22 of the high-pressure high-purity nitrogen bottle, open the pressure reducing valve, and fill the high-purity nitrogen into the calcining cylinder 9 through the pressure reducing valve 23, the air inlet micro solenoid valve 1, and the piston column micro solenoid valve 17; 9) When the pressure reaches the set value, close the piston column micro solenoid valve 17, the air inlet micro solenoid valve 1, the pressure reducing valve 23, and the main valve 22 on the high-pressure high-purity nitrogen bottle in sequence, stop injecting high-purity nitrogen, and remove the external connecting pipe on the left side of the rotary calcining device; 10) Turn on the driving mechanism 20 and the annular electric heating block 10 in sequence, and heat the calcining tube to achieve uniform rotational heating and calcining of the silicon dioxide in the calcining tube; when the set calcining temperature is reached, the set temperature is maintained for calcination, and the wireless temperature sensor 12 transmits the temperature measurement data to the control module, and the control module performs automatic temperature control according to the set temperature; 11) When the pressure in the calcining tube 9 exceeds the set spring force of the telescopic spring 3 due to heating or the escape of gas inside the silica powder, the hollow piston column 7 moves toward the left end of the extension tube 5, and vice versa, always maintaining stable calcination within the set pressure range; 12) When the calcination time is reached, the annular electric heating block 10 and the driving mechanism 20 are turned off in sequence; 13) When the temperature drops to room temperature, open the outlet micro solenoid valve 16 on the right side of the rotary calcining device to release the pressure in the rotary calcining device; 14) Unscrew the sealing cover 15 on the right side of the rotary calcining device and take out the qualified calcined silicon dioxide; 15) Clean the inside of the calcination tube 9, reinstall the cylindrical heat-insulating filter block 18 and the sealing cover 15 on the right, close the air outlet micro solenoid valve 16 on the right, and prepare for the next cycle of calcination.

[0037] The above description is only a preferred embodiment of the present invention. For ordinary technicians in this field, according to the teachings of the present invention, it does not require creative labor to design different forms of silicon dioxide calcining devices and methods with dynamic pressure-stabilized inert gas protection. Without departing from the principles and spirit of the present invention, all equal changes, modifications, substitutions and variations made within the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A silicon dioxide calcining device with dynamic pressure stabilization inert gas protection, comprising a rotary calcining device, a dynamic pressure stabilization adjustment device, an inert gas protection device and a vacuum pumping mechanism, characterized in that: The rotary calcining device includes a calcining cylinder driven to rotate by a driving mechanism, and both left and right ends of the calcining cylinder are provided with heat insulation filtering structures, and an extension tube with a sealing cover detachably connected to the outer end is fixed on the heat insulation filtering structure, and the dynamic voltage stabilization adjustment device is arranged in the extension tube on one side.

2. The silicon dioxide calcining device with dynamic pressure-stabilized inert gas protection according to claim 1, characterized in that: The dynamic pressure stabilization adjustment device includes a hollow piston column arranged in the left outer tube, the outer circular surface of the hollow piston column contacts the inner diameter surface of the left outer tube to form a mirror dynamic seal, and a telescopic spring is installed between the left end of the hollow piston column and the left sealing cover.

3. The silicon dioxide calcining device with dynamic pressure-stabilized inert gas protection according to claim 2, characterized in that: A ventilation pipe is installed axially in the center of the hollow piston column. The right end of the ventilation pipe is connected to the air outlet arranged on the right side of the hollow piston column through the piston column micro-solenoid valve. The left end of the ventilation pipe passes through the left side of the hollow piston column and the sealing cover on the left side in turn and is connected to the air intake micro-solenoid valve. The ventilation pipe and the sealing cover on the left side are slidably matched.

4. The silicon dioxide calcining device with dynamic pressure-stabilized inert gas protection according to claim 3, characterized in that: The inert gas protection device comprises an inert gas bottle, the outlet of the inert gas bottle is detachably connected to an air intake micro solenoid valve via a pressure reducing valve, and a pressure sensor is installed between the pressure reducing valve and the air intake micro solenoid valve.

5. The silicon dioxide calcining device with dynamic pressure-stabilized inert gas protection according to claim 4, characterized in that: The vacuum pumping mechanism comprises a vacuum pump, and the input end of the vacuum pump is connected to the air outlet micro electromagnetic valve installed on the sealing cover on the right side.

6. The silicon dioxide calcining device with dynamic pressure-stabilized inert gas protection according to claim 1, 2, 3, 4 or 5, characterized in that: The heat-insulating filtering structure comprises short heat-insulating tubes fixed on the left and right ends of the calcining tube, cylindrical heat-insulating filtering blocks are installed in the short heat-insulating tubes, and the extension tube is fixed on the outer end of the short heat-insulating tubes.

7. The silicon dioxide calcining device with dynamic pressure-stabilized inert gas protection according to claim 1, 2, 3, 4 or 5, characterized in that: The outer circumferential surface of the calcining cylinder is closely mounted with a circular electric heating block that matches the circumference thereof, and the outer circumferential surface of the circular electric heating block is mounted with a heat preservation layer.

8. The silicon dioxide calcining device with dynamic pressure-stabilized inert gas protection according to claim 7, characterized in that: A wireless temperature sensor is installed outside the thermal insulation layer, and the probe sequentially passes through the thermal insulation layer, the annular electric heating block and is in close contact with the outer wall of the calcination tube.

9. The silicon dioxide calcining device with dynamic pressure-stabilized inert gas protection according to claim 1, 2, 3, 4 or 5, characterized in that: The sealing covers are respectively spiral sealing covers and are threadedly connected to the outer ends of the corresponding extension tubes. Transmission gears are installed on the outer circumferences of the extension tubes, and the transmission gears are rotationally transmitted with the driving mechanism.

10. A method for calcining silicon dioxide with dynamic pressure-stabilizing inert gas protection, comprising the device for calcining silicon dioxide with dynamic pressure-stabilizing inert gas protection as claimed in claim 5, characterized in that: The following steps are involved: 1) Pre-install a telescopic spring with appropriate telescopic force according to the required pressure of calcined silica; 2) Remove the sealing cover on the right side of the rotary calcining device and take out the cylindrical heat-insulating filter block in the heat-insulating filter structure on the right side of the calcining cylinder; 3) Measure and load the silica powder to be calcined into the calcination cylinder, and reinstall the cylindrical insulation filter block and sealing cover on the right side in sequence; 4) Connect the inert gas protection device to the left sealing cover and the vacuum device to the right sealing cover; 5) Open the air inlet micro solenoid valve, piston column micro solenoid valve, and air outlet micro solenoid valve in sequence; 6) Turn on the vacuum pump to evacuate the above connecting pipes, pipe fittings and the inside of the rotary calcining device; 7) When the vacuum setting value is reached, close the outlet micro solenoid valve and vacuum pump in sequence, and remove the external pipeline connected to the right side of the rotary calcining device; 8) Open the main valve on the inert gas bottle, open the pressure reducing valve, and fill the high-purity nitrogen into the calcining cylinder through the pressure reducing valve, the air inlet micro solenoid valve, and the piston column micro solenoid valve; 9) When the pressure reaches the set value, close the piston column micro solenoid valve, the air inlet micro solenoid valve, the pressure reducing valve, and the main valve on the inert gas bottle in sequence, stop injecting high-purity nitrogen, and remove the external pipeline connected to the left side of the rotary calcining device; 10) Turn on the driving mechanism and heat the calcining cylinder to achieve uniform rotation, heating and calcination of the silicon dioxide in the calcining cylinder; when the set calcination temperature is reached, maintain the set temperature for calcination; 11) When the pressure in the calcining cylinder exceeds the set telescopic spring force due to heating or gas escape from the silica powder, the hollow piston column moves toward the left extension tube port, and vice versa, always maintaining stable calcination within the set pressure range; 12) When the calcination time is reached, the heating and driving mechanisms of the calcination cylinder are turned off in sequence; 13) When the temperature drops to room temperature, open the outlet micro solenoid valve on the right side of the rotary calcining device to release the pressure in the rotary calcining device; 14) Unscrew the sealing cover on the right side of the rotary calcining device and take out the qualified calcined silicon dioxide; 15) Clean the inside of the calcination cylinder, reinstall the cylindrical heat-insulating filter block and the sealing cover on the right, close the air outlet micro solenoid valve on the right, and prepare for the next calcination cycle.

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