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CN-121977331-A - Mild drying and calcining system and method for thin-wall hollow silicon oxide microspheres

CN121977331ACN 121977331 ACN121977331 ACN 121977331ACN-121977331-A

Abstract

The application discloses a gentle drying and calcining system and a gentle drying and calcining method for thin-wall hollow silicon oxide microspheres, and belongs to the field of advanced inorganic material preparation. The system is provided with at least one built-in functional component along the axial direction of the cylinder, a plurality of shoveling plates with built-in functional components are annularly arranged on the inner wall of the cylinder, an air distribution plate is arranged in the center of the radial section of the cylinder, at least two support annular arrays are arranged between the air distribution plate and the inner wall of the cylinder, a driving mechanism is connected with a first end of the cylinder through a transmission mechanism, a hot air generator is communicated with an air inlet of the cylinder through a hot air input pipe, a first end of a discharging pipe is rotationally connected with a discharging hole, the cylinder rotates at a low speed relative to the discharging pipe, a second end of the discharging pipe is communicated with a cyclone separator, the cyclone separator is communicated with a vibration dispersing and sieving mechanism, the vibration dispersing and sieving mechanism is communicated with a spiral conveyor, and the spiral conveyor is communicated with a calciner. The application can ensure that the fragile hollow structure reduces damage in the drying, calcining and dispersing stages, avoids hard agglomeration and realizes industrial production above ton level.

Inventors

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Assignees

  • 上海纳鸿微球科技有限公司

Dates

Publication Date
20260505
Application Date
20260123

Claims (10)

  1. 1. The gentle drying and calcining system for the thin-wall hollow silicon oxide microspheres is characterized by comprising a driving mechanism, a transmission mechanism, a roller, a hot air generator, a hot air input pipe, a discharging pipe, a cyclone separator, a vibration dispersing and sieving mechanism, a screw conveyor and a calcining furnace; The roller comprises a roller body and an internal functional component; the side wall of the cylinder body is provided with a feed inlet, the first end face is provided with an air inlet, and the second end face is provided with a discharge outlet; at least one built-in functional component is arranged along the axial direction of the cylinder body; The built-in functional component comprises a shoveling plate, a bracket and an air distribution plate; The shoveling plates are arranged on the inner wall of the cylinder body in an annular array around the axis of the cylinder body; The air distribution plate is arranged in the center of the radial section of the cylinder body, is opposite to the air inlet and is used for dispersing hot air into uniform air flow; the support comprises at least two supports, the first ends of the at least two supports are annularly arranged on the outer wall of the air distribution plate, and the second ends of the at least two supports are arranged on the inner wall of the cylinder; the driving mechanism is connected with the first end of the roller through the transmission mechanism; The hot air generator is communicated with the air inlet of the roller through the hot air input pipe; the first end of the discharging pipe is rotationally connected with the discharging hole, and the roller rotates at a low speed relative to the discharging pipe under the driving of the driving mechanism; The second end of the discharging pipe is communicated with the input port of the cyclone separator; the output port of the cyclone separator is communicated with the input port of the vibration dispersing and sieving mechanism; the output port of the vibration dispersing and sieving mechanism is communicated with the input port of the screw conveyor; The output port of the screw conveyor is communicated with the input port of the calciner.
  2. 2. The mild drying and calcining system for thin-walled hollow silica microspheres according to claim 1, wherein a plurality of through holes are uniformly distributed on the air distribution plate, or a plurality of elongated slits are arranged in parallel on the air distribution plate.
  3. 3. The mild drying calcination system for thin-walled hollow silica microspheres according to claim 1, further comprising an exhaust gas treatment mechanism; the tail gas treatment mechanism is arranged at the top of the cyclone separator.
  4. 4. The mild dry calcination system for thin-walled hollow silica microspheres according to claim 1, wherein the vibration dispersion sieving mechanism comprises a sieve box, a screen, and a vibration mechanism; The input port at the top of the screen box is communicated with the output port of the cyclone separator, and the screen is clamped at the lower part of the screen box; the vibration mechanism is connected with the screen and is used for driving the screen to vibrate; the inner cavity of the sieve box below the screen is in a table shape; the output port of the sieve box is communicated with the input port of the screw conveyor.
  5. 5. The mild dry calcination system for thin-walled hollow silica microspheres according to claim 4, wherein the vibration dispersion sieving mechanism further comprises an acoustic wool; the soundproof cotton set up in the outer wall of screen cloth is located the below of screen cloth in the screen box.
  6. 6. A method for mildly drying and calcining thin-walled hollow silica microspheres, characterized in that the mildly drying and calcining system based on the thin-walled hollow silica microspheres according to any one of claims 1 to 5 comprises: Step1, feeding thin-wall hollow silicon oxide precursor slurry with the solid content of 5% -25% into a roller through a feed inlet arranged on the side wall of a barrel body of the roller, wherein the roller rotates at a low speed relative to a discharge hole under the driving of a driving mechanism; Step 2, repeatedly lifting the thin-wall hollow silicon oxide precursor slurry to a certain height through a plurality of shoveling plates which are annularly arranged on the inner wall of the cylinder around the axis of the cylinder, freely scattering the thin-wall hollow silicon oxide precursor slurry by means of gravity to form a uniform and continuous thin-layer dynamic material curtain, and simultaneously, introducing low-temperature hot air with the temperature of 60-180 ℃ into the cylinder through a hot air input pipe and an air inlet of the cylinder by a hot air generator, wherein the low-temperature hot air is uniformly distributed on the center of the radial section of the cylinder through an air distribution plate which is opposite to the air inlet, and then fully and gently contacts and transfers mass with the thin-layer dynamic material curtain to obtain precursor microspheres; step 3, the precursor microspheres are output to a discharge pipe from the discharge port of the cylinder body through the driving of air flow, are conveyed to a cyclone separator through an output port of the discharge pipe, and are subjected to gas-solid separation in the cyclone separator to obtain solid microspheres; Step 4, conveying the solid microspheres to a vibration dispersing and sieving mechanism through an output port of the cyclone separator, and performing gentle dispersion under the adjustable low-frequency low-amplitude vibration of the vibration dispersing and sieving mechanism to obtain monodisperse precursor microspheres, and outputting the monodisperse precursor microspheres to an output port of the vibration dispersing and sieving mechanism; and 5, conveying the monodisperse precursor microspheres to a screw conveyor through an output port of the vibration dispersing and sieving mechanism, then conveying the microspheres to a calciner in a closed manner through the screw conveyor, and calcining the microspheres at a temperature rising rate of 1-5 ℃ to 300-800 ℃ in an air atmosphere, wherein the temperature is maintained for 1-8 hours, so as to obtain the hollow silicon oxide microspheres.
  7. 7. The method for mild drying and calcining of thin-walled hollow silica microspheres according to claim 6, wherein the rotation speed of the drum rotating at a low speed in step 1 is 5rpm to 25rpm.
  8. 8. The method of mild drying and calcining thin-walled hollow silica microspheres according to claim 6, further comprising the step of collecting the separated tail gas by a tail gas treatment mechanism.
  9. 9. The method for mildly drying and calcining thin-walled hollow silica microspheres according to claim 6, wherein step 4 specifically comprises conveying the solid microspheres to a sieve box through an output port of the cyclone separator; the vibration mechanism drives the screen to vibrate at low frequency and low amplitude, and the screen gently disperses the solid microspheres to obtain the monodisperse precursor microspheres; the monodisperse precursor microspheres are collected to an output port of the sieve box through a table-shaped inner cavity of the sieve box.
  10. 10. The mild drying and calcining method for thin-wall hollow silica microspheres according to claim 9, wherein the vibration frequency of the vibration mechanism is 15-40 hz, the amplitude is 0.5-2 mm, and the mesh number of the screen is 200-2000 mesh.

Description

Mild drying and calcining system and method for thin-wall hollow silicon oxide microspheres Technical Field The application relates to the technical field of advanced inorganic material preparation, in particular to a mild drying and calcining system and method for thin-wall hollow silicon oxide microspheres. Background The thin-wall hollow silicon oxide microsphere has unique nano-to submicron-level wall thickness structure, and shows irreplaceable value in high-end application fields such as a high-end drug delivery system, a high-performance catalyst carrier, a precise microreactor, a next-generation heat insulation material and the like. Such thin-walled hollow silica microspheres are typically prepared by a templating process (e.g., emulsion templating or polymeric templating), the precursor of which is in the form of a wet gel, and the structure of which is extremely fragile. However, the post-treatment stage requires the wet gel to be converted into a dry, strong and well-dispersed final product, which presents serious technical challenges, especially on an industrial scale, how to protect the thin-walled hollow structure from damage, which is a core bottleneck that restricts its widespread use. Currently, the dominant drying techniques in the industry include spray drying, static drying (e.g., ovens or tunnel kilns), and freeze drying. The spray drying relies on a high-speed rotary atomizing disc (the rotating speed is usually 10000 rpm-30000 rpm) or a high-pressure nozzle to realize atomization and drying, and has higher efficiency. The static drying is finished by evaporating the solvent by adopting an oven, a tunnel kiln and the like. Freeze-drying utilizes supercritical or cryogenic freezing conditions to avoid the effects of capillary forces. Although the technology is mature in general material treatment, the technology has obvious limitation aiming at the special requirements of the thin-wall hollow silicon oxide microspheres, and cannot meet the requirements of structural integrity and mass production. The high shear force generated during spray drying is very easy to tear or crush the formed wet gel hollow spheres with extremely low strength, even if not completely crushed, the generated microcracks can be expanded in subsequent treatments such as calcination, so that the strength of the product is far lower than a theoretical value, the yield is often less than 50%, and the spray drying faces the dilemma of shearing damage. Although static drying does not have shear damage, the huge capillary force caused by solvent evaporation can lead particles to form firm chemical bonding (hard agglomeration) to form hard blocks, the hard blocks are extremely difficult to disperse, any subsequent mechanical crushing (such as grinding) can irreversibly damage the hollow structure, and the particle size distribution is out of control. Although the freeze drying can avoid capillary force and shearing force, the equipment investment is huge (for example, the price of a medium-sized laboratory freeze dryer can reach hundreds of thousands yuan), the energy consumption is extremely high, the period is long (often reaching a plurality of days), the treatment capacity is limited, and the industrial production above ton level can not be realized at all. Disclosure of Invention The embodiment of the application provides a mild drying and calcining system and a mild drying and calcining method for thin-wall hollow silicon oxide microspheres, which can solve the problems that high shearing force generated by the existing thin-wall hollow silicon oxide microsphere drying technology is very easy to tear or crush the formed wet gel hollow spheres with extremely low strength, hard agglomeration is easy, and industrial production above ton level cannot be realized. In order to achieve the above object, the technical solution of the embodiment of the present invention is: In a first aspect, an embodiment of the present invention provides a mild drying and calcining system for thin-walled hollow silica microspheres, which is characterized by comprising a driving mechanism, a transmission mechanism, a roller, a hot air generator, a hot air input pipe, a discharging pipe, a cyclone separator, a vibration dispersing and sieving mechanism, a screw conveyor and a calciner; The roller comprises a roller body and an internal functional component; the side wall of the cylinder body is provided with a feed inlet, the first end face is provided with an air inlet, and the second end face is provided with a discharge outlet; at least one built-in functional component is arranged along the axial direction of the cylinder body; The built-in functional component comprises a shoveling plate, a bracket and an air distribution plate; The shoveling plates are arranged on the inner wall of the cylinder body in an annular array around the axis of the cylinder body; The air distribution plate is arranged in the center of the radial section of