Preparation method and preparation system of silicon dioxide for vitamin carrier

Abstract

The invention discloses a preparation method and a preparation system of silicon dioxide for a vitamin carrier, and relates to the technical field of silicon dioxide, the preparation system comprises a drying tower and an atomizing nozzle mounted on the drying tower, and further comprises a lifting air guide mechanism mounted in the drying tower, and a driving part for driving the lifting air guide mechanism to rotate is mounted at the bottom of the drying tower; the bottom of the drying tower is in a funnel shape and provided with a plurality of annular protrusions distributed in the discharging direction, the lifting air guiding mechanism is sleeved with a material stirring mechanism rotating coaxially with the lifting air guiding mechanism, the material stirring mechanism is in clearance fit with the annular protrusions, and a vibration assembly matched with the lifting flow pushing mechanism in an abutting mode is installed in the material stirring mechanism. When hot air enters the drying tower, the driving piece drives the lifting flow pushing mechanism to push the hot air upwards. The air guide mechanism is controlled by the driving part to vertically lift in the tower, hot air entering the drying tower is forcibly pushed upwards from the bottom, a directional vortex is formed, and the temperature gradient is eliminated.

Description

Technical Field

[0001] The present invention relates to the technical field of silicon dioxide, in particular to a method and a system for preparing silicon dioxide for vitamin carriers. Background Art

[0002] Due to its chemical inertness, high specific surface area, controllable pore structure and good biocompatibility, silicon dioxide is widely used as a functional carrier material in the fields of medicine, food, feed, etc. In vitamin preparations, silicon dioxide is often used as an adsorbent or sustained-release carrier. During the preparation process, a spray drying tower is required to dry and granulate the slurry. Spray drying is a drying process in which the raw liquid is placed in an atomizer to separate it into droplets, and the powder-shaped product is obtained by direct contact between hot air or other gases and the droplets.

[0003] The patent publication number of the existing patent application is: CN215312166U, and the publication date is December 28, 2021. The name of the patent is "A spray granulator". The patent includes: a shell, an atomizer, a fluidized bed, and a blower. The side wall of the shell is provided with an air outlet, and the bottom end of the side wall of the shell is provided with a particle discharge port; the atomizer is arranged at the upper end of the shell, used to atomize the slurry and spray it into the shell; the fluidized bed includes an air distribution plate and an air chamber, the air distribution plate is horizontally arranged at the bottom end of the shell and located below the particle discharge port, the air chamber is located below the air distribution plate, and the air distribution plate is provided with multiple ventilation pipes connected to the air chamber; the blower is connected to an air outlet, and the blower is used to transport air into the air outlet. The air outlet is connected to a heater, the heater is connected to the upper end of the shell, and the air outlet is connected to the air chamber. The utility model provides a spray granulator, in which the granular material can be directly bagged after being discharged from the particle discharge port without waiting for cooling, which effectively prevents burns to personnel, improves safety, and improves work efficiency.

[0004] The existing precipitation method for preparing vitamin carrier silica has problems such as many raw material impurities, easy agglomeration of particles resulting in poor structure, high residual sodium sulfate as a by-product, high energy consumption, and uneven product particle morphology. The above application also has shortcomings. The bottom of the drying tower is generally funnel-shaped, and silica particles are easy to accumulate in the conical area, forming bridge blockages, resulting in poor discharge and frequent shutdowns for cleaning. At the same time, the fixed air guide structure is difficult to dynamically adjust the direction of hot air flow, resulting in a temperature gradient in the tower, with the upper temperature being overheated and the lower temperature being insufficient. This not only reduces the drying efficiency, but also causes local overheating or underheating of the material. The static air guide mechanism cannot drive the airflow to fully diffuse to the tower wall, causing the atomized droplets to condense and accumulate on the tower wall, forming a stubborn wall-sticking layer, which reduces the product yield. Summary of the Invention

[0005] The purpose of the present invention is to provide a method and system for preparing silicon dioxide for vitamin carriers to address the deficiencies in the above-mentioned prior art.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A method for preparing silicon dioxide for vitamin carrier, characterized by comprising the following steps:

[0008] S1. Prepare a sodium silicate solution with a mass concentration of 15-20% by weight of solid sodium silicate having a modulus of 3.0-3.5, add polyaluminium chloride and chitosan composite flocculant with a mass concentration of 0.5-1.0%, stir at 80-100 r / min for 60 min, and let stand for 60 min to obtain a high-purity sodium silicate solution;

[0009] S2, adding alkylphenol polyoxyethylene ether to the obtained solution, and preparing a sulfuric acid solution with a mass concentration of 10-15%;

[0010] S3. Add industrial water to the reactor to a volume ratio of 1 / 6, heat to 30-40°C, add the sodium silicate solution from step 2, and stir at 60-80 rpm;

[0011] S4. Raise the temperature to 45-55°C, adjust the stirring rate to 80-100 r / min, and simultaneously add sodium silicate solution and sulfuric acid solution dropwise until the volume of the reaction system accounts for 40% of the kettle volume. Control the pH to 7.5-8.5, react for 60 minutes, continue to add sulfuric acid solution dropwise until the pH is 4.5-5.5, and age for 30 minutes;

[0012] S5. After filtration, the filter cake is washed with industrial water. The sodium sulfate content of the finished product is controlled to be less than 2% by the conductivity of the washing water. The solid content of the filter cake is adjusted to 20-25% before beating;

[0013] S5. The concentrated slurry is sent to a spray dryer for drying, using hot air from natural gas combustion as a heat source to obtain granular silicon dioxide.

[0014] In the above scheme, the performance of the silica product is significantly improved by deeply purifying the raw materials with a composite flocculant, regulating the reaction process with a dispersant, and precisely controlling the washing and spray drying processes with conductivity. Metal impurities are effectively removed, and high purity, high specific surface area and optimized pore structure, low sodium sulfate residue, good particle morphology and fluidity are obtained. At the same time, the energy consumption is significantly reduced due to the combination of spray drying and natural gas heat source, which overall achieves a safer, more efficient, stable and energy-saving preparation of high-performance silica carriers suitable for vitamin loading.

[0015] Preferably, the composite flocculant is composed of polyaluminium chloride and chitosan, and the added amount is 0.5-1.0% of the total mass of the sodium silicate solution. The heavy metals and impurities are removed simultaneously during the stirring process.

[0016] The silica preparation system for vitamin carriers used in the above-mentioned preparation method includes a drying tower and an atomizing nozzle installed on the drying tower, and also includes a lifting air guide mechanism, which is installed inside the drying tower, and a driving member for driving the lifting air guide mechanism to rotate is installed at the bottom of the drying tower. The bottom of the drying tower is funnel-shaped and is provided with a plurality of annular protrusions distributed along the discharge direction. The lifting air guide mechanism is externally connected to a paddle mechanism that rotates coaxially with the lifting air guide mechanism, and the paddle mechanism is gap-matched with the annular protrusions. A vibration component is installed in the paddle mechanism that abuts against the lifting and pushing flow mechanism. When hot air enters the drying tower, the driving member drives the lifting and pushing flow mechanism to push the hot air upward, and drives the paddle mechanism to rotate to accelerate the airflow at the bottom of the drying tower to blow toward the lifting and pushing flow mechanism and diffuse to the inner wall of the drying tower.

[0017] Preferably, the driving member includes a driving motor fixed to the bottom of the drying tower, the output shaft of the driving motor is installed with a connecting sleeve in the drying tower, and the bottom of the lifting and air guiding mechanism is movably inserted in the connecting sleeve.

[0018] Preferably, the lifting air guide mechanism includes a shaft rod inserted in a connecting shaft sleeve, the top end of the shaft rod is fixedly connected to an air guide plate, the air guide plate is located below the atomizing nozzle, the bottom of the shaft rod is fixedly connected to an abutting cross bar, and a guide ring for overlapping the abutting cross bar is fixedly connected in the drying tower, and a plurality of arc grooves are distributed in an annular manner on the guide ring.

[0019] Preferably, the material-dispensing mechanism comprises a sleeve coaxially sleeved with the shaft rod, a plurality of blades are fixedly connected to the outer wall of the sleeve, and grooves matching the annular protrusions are formed on the blades.

[0020] Preferably, the vibration assembly includes a pair of abutment rods elastically inserted in the sleeve, key slots are vertically opened on both sides of the shaft, abutment teeth are provided in the key slots, and one end of the abutment rod extends into the key slot and abuts against the abutment teeth.

[0021] Preferably, both sides of the blade are fixedly connected with air guide covers, and the other end of the abutment rod is symmetrically fixedly connected with air pusher plates respectively located in each air guide cover.

[0022] Preferably, the bottom of the drying tower is provided with an annularly distributed discharge port, and a discharge tray is fixedly connected to the shaft, and the discharge tray is located below the discharge port.

[0023] Preferably, an annular collecting net is installed on the top of the inner wall of the drying tower, and a plurality of heat conducting fins are provided on the top surface of the annular collecting net.

[0024] In the above technical solution, a driving member is provided to control the vertical lifting of the air guide mechanism in the tower, so that the hot air entering the drying tower is forced to be pushed upward from the bottom to form a directional vortex, thereby eliminating the temperature gradient. The annular protrusion at the bottom of the tower is clearance-matched with the rotating material-dispensing mechanism to limit the lifting of the material-dispensing mechanism, so that the vibration component embedded in the material-dispensing mechanism is dynamically in contact with the lifting air guide mechanism to generate high-frequency micro-vibration waves and disintegrate the bridging structure. When the material-dispensing mechanism rotates, the flow speed of the bottom airflow is also increased, so that the bottom airflow is quickly guided to the lifting air guide mechanism to force the hot air to diffuse to the entire tower wall, thereby avoiding condensation and accumulation of atomized droplets on the tower wall and improving the yield.

[0025] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

[0026] This application document provides an overview of various implementations or examples of the technology described in this disclosure, and is not a comprehensive disclosure of the full scope or all features of the disclosed technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments described in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0028] Figure 1 This is a schematic diagram of the overall structure of a silicon dioxide preparation system for vitamin carriers of the present invention;

[0029] Figure 2 This is a cross-sectional view of a system for preparing silicon dioxide for use as a vitamin carrier according to the present invention;

[0030] Figure 3 For the present invention Figure 2 A magnified view of the structure at point A;

[0031] Figure 4 This is a schematic diagram of the internal structure of a drying tower in a system for preparing silicon dioxide for use as a vitamin carrier according to the present invention;

[0032] Figure 5 This is a schematic diagram of the connection between the lifting and air guiding mechanism and the material dispensing mechanism in the silicon dioxide preparation system for vitamin carriers of the present invention;

[0033] Figure 6 This is a schematic diagram of the connection between the material feeding mechanism and the vibration component in the silicon dioxide preparation system for vitamin carriers of the present invention;

[0034] Figure 7 This is a schematic structural diagram of a sleeve and a vibration component in a system for preparing silica for vitamin carriers according to the present invention;

[0035] Figure 8 This is a schematic structural diagram of a vibration component in a silica preparation system for vitamin carriers of the present invention.

[0036] Description of reference numerals:

[0037] 1. Drying tower; 101. Discharge port; 2. Atomizing nozzle; 3. Lifting air guide mechanism; 31. Shaft; 32. Air guide plate; 33. Abutment cross bar; 34. Guide ring; 35. Arc groove; 36. Keyway; 37. Abutment tooth; 4. Driving member; 41. Driving motor; 42. Connecting sleeve; 5. Annular protrusion; 6. Material feeding mechanism; 61. Sleeve; 62. Blade; 63. Groove; 64. Air guide cover; 7. Vibrating assembly; 71. Abutment rod; 72. Air push plate; 73. Top spring; 8. Discharge tray; 9. Annular collection net; 91. Heat conducting plate. DETAILED DESCRIPTION

[0038] To make the purpose, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0039] See also Figure 1-8 The present invention provides a method for preparing silicon dioxide for vitamin carriers, which comprises the following steps:

[0040] S1. Prepare a sodium silicate solution with a mass concentration of 15-20% by weight of solid sodium silicate having a modulus of 3.0-3.5, add polyaluminium chloride and chitosan composite flocculant with a mass concentration of 0.5-1.0%, stir at 80-100 r / min for 60 min, and let stand for 60 min to obtain a high-purity sodium silicate solution;

[0041] S2, add alkylphenol polyoxyethylene ether to the resulting solution in an amount of 0.5% of the theoretical mass of silicon dioxide, and prepare a sulfuric acid solution with a mass concentration of 10-15%;

[0042] S3. Add industrial water to the reactor to a volume ratio of 1 / 6, heat to 30-40°C, add the sodium silicate solution from step 2, and stir at 60-80 rpm;

[0043] S4. Raise the temperature to 45-55°C, adjust the stirring rate to 80-100 r / min, and simultaneously add sodium silicate solution and sulfuric acid solution dropwise until the volume of the reaction system accounts for 40% of the kettle volume. Control the pH to 7.5-8.5, react for 60 minutes, continue to add sulfuric acid solution dropwise until the pH is 4.5-5.5, and age for 30 minutes;

[0044] S5. After filtration, the filter cake is washed with industrial water. The sodium sulfate content of the finished product is controlled to be less than 2% by the conductivity of the washing water. The solid content of the filter cake is adjusted to 20-25% before beating;

[0045] S5. The concentrated slurry is sent to a spray dryer for drying, using hot air from natural gas combustion as a heat source to obtain granular silicon dioxide.

[0046] In a further embodiment of the present invention, the composite flocculant is composed of polyaluminum chloride and chitosan, and the added amount is 0.5-1.0% of the total mass of the sodium silicate solution. During the stirring process, heavy metals and impurities are removed simultaneously.

[0047] The vitamin carrier silica preparation system used in the above preparation method includes a drying tower 1 and an atomizing nozzle 2 installed on the drying tower 1, and also includes a lifting air guide mechanism 3, which is installed inside the drying tower 1, and a driving member 4 for driving the lifting air guide mechanism 3 to rotate is installed at the bottom of the drying tower 1. The bottom of the drying tower 1 is funnel-shaped and is provided with a plurality of annular protrusions 5 distributed along the discharge direction. The lifting air guide mechanism 3 is externally connected to a paddle mechanism 6 that rotates coaxially with it. The paddle mechanism 6 is gap-fitted with the annular protrusion 5, and a vibration component 7 is installed in the paddle mechanism 6 that abuts against the lifting and pushing flow mechanism. When hot air enters the drying tower 1, the driving member 4 drives the lifting and pushing flow mechanism to push the hot air upward, and drives the paddle mechanism 6 to rotate so that the airflow at the bottom of the drying tower 1 is accelerated to blow toward the lifting and pushing flow mechanism 3 and diffuse to the inner wall of the drying tower 1.

[0048] Specifically, the drying tower 1 has a vertical cylindrical structure with a funnel-shaped bottom. An atomizing nozzle 2 is installed at the center of the top of the tower to atomize the solution into micron-sized droplets and spray them out in the drying tower 1. A hot air duct is provided on the side of the drying tower 1 and is connected to the hot air supply system. When the atomizing nozzle 2 sprays the solution, the driving part 4 is started. On the one hand, it drives the lifting and guiding mechanism 3 to rotate and move up and down within a certain range, which plays a role in guiding and pushing the hot air upward, changing the path of the hot air after entering the traditional tower and enhancing the air flow disturbance. On the other hand, the driving part 4 can drive the material diverting mechanism 6 to rotate close to the annular protrusion 5 area at the bottom of the tower through the lifting and guiding mechanism 3. When the blades 62 rotate, they will stir the powder and airflow accumulated at the bottom of the tower, and The powder is thrown up, and at the same time, the bottom airflow is driven to rush to the lifting air guide mechanism 3 in the center, and then diffused to the tower wall through the obstruction of the lifting air guide, forming a hot air flow circulation pattern that diffuses from the center upward and then to the periphery. The atomized droplets are fully in contact and mixed with the disturbed rising hot air during the descent process, and the moisture is quickly evaporated to form fine, dry silica powder particles. The lifting motion enhances the turbulence of the fluid and improves the heat and mass transfer efficiency. The rotation of the material-dispensing mechanism 6 effectively prevents the accumulation and adhesion of wet materials and semi-dry powders at the bottom of the tower, which is particularly suitable for hygroscopic or sticky materials, and promotes the rising of the bottom airflow. The vibration component 7 generates high-frequency micro-vibration when working, which further assists the powder to separate from the lifting air guide mechanism 3 and the tower wall.

[0049] Compared with the prior art, the embodiment of the present invention controls the vertical lifting of the air guide mechanism in the tower through the driving member 4, forcing the hot air entering the drying tower 1 to be pushed upward from the bottom, forming a directional vortex and eliminating the temperature gradient. The annular protrusion 5 at the bottom of the tower is clearance-matched with the rotating material-dispensing mechanism 6 to limit the lifting of the material-dispensing mechanism 6, so that the vibration component 7 embedded in the material-dispensing mechanism 6 is dynamically abutted with the lifting air guide mechanism 3 to generate high-frequency micro-vibration waves and disintegrate the bridging structure. When the material-dispensing mechanism 6 rotates, the flow speed of the bottom airflow is also increased, so that the bottom airflow is quickly guided to the lifting air guide mechanism 3 to force the hot air to diffuse to the entire tower wall, thereby avoiding condensation and accumulation of atomized droplets on the tower wall, improving the yield, and preventing adhesion to the inner wall of the drying tower 1.

[0050] In a further embodiment of the present invention, the driving member 4 includes a driving motor 41 fixed to the bottom of the drying tower 1, and the output shaft of the driving motor 41 is installed with a connecting shaft sleeve 42 in the drying tower 1, and the bottom of the lifting air guide mechanism 3 is movably inserted in the connecting shaft sleeve 42. Specifically, the driving motor 41 drives the connecting shaft sleeve 42 to rotate through its output shaft. Since the lifting air guide mechanism 3 is movably inserted in the connecting shaft sleeve 42, the driving motor 41 can drive the lifting air guide mechanism 3 to rotate synchronously when it rotates, but at the same time allows the lifting air guide mechanism 3 to slide up and down in the axial direction relative to the connecting shaft sleeve 42 to meet the needs of the lifting air guide mechanism 3 to move up and down. The connecting shaft sleeve 42 also plays a supporting and positioning role for the bottom of the lifting mechanism, ensuring that the lifting air guide mechanism 3 can accurately push the hot air flow from the middle of the drying tower 1.

[0051] In a further embodiment of the present invention, the lifting air guide mechanism 3 includes a shaft rod 31 inserted in the connecting shaft sleeve 42, the top of the shaft rod 31 is fixedly connected to an air guide plate 32, the air guide plate 32 is located below the atomizing nozzle 2, the bottom of the shaft rod 31 is fixedly connected to an abutting cross bar 33, and a guide ring 34 for the abutting cross bar 33 to overlap is fixedly connected in the drying tower 1, and a plurality of arc grooves 35 are distributed in an annular manner on the guide ring 34. Specifically, the shaft rod 31 rotates under the drive member 4 and rises and falls with the movement of the abutting cross bar 33. The air guide plate 32 is located below the atomizing area and has a disc-shaped structure with a raised center. Its function is to push the hot air in the tower upward when the shaft rod 31 drives it to rise, thereby expanding the contact area between the hot air and the atomized droplets and powder particles. The abutting cross bar 33 at the bottom of the shaft rod 31 is placed on the guide ring 34 fixed to the inner wall of the tower. The guide ring 34 is stationary. When the driving motor 41 drives the shaft 31 to rotate the shaft 31 together with the abutting cross bar 33, the end of the abutting cross bar 33 slides on the annular surface of the guide ring 34 and these specific arc grooves 35. When sliding to a smooth place, the shaft 31 is in a higher position. When sliding to the recessed position of the arc groove 35, the abutting cross bar 33 will sink along the groove shape, so that the entire shaft 31 and the top air guide plate 32 will drop a distance under the action of gravity. After continuing to rotate and sliding out of the recessed groove, the shaft 31 and the air guide plate 32 will rise again, and this cycle will repeat. While rotating, the air guide plate 32 continuously makes up and down reciprocating motion, forming a lifting stirring effect, significantly enhancing the up and down tumbling of the hot air flow, preventing the material from compacting or staying in a specific area, and improving the drying effect of the material in the drying tower 1.

[0052] In a further embodiment of the present invention, the material-diverting mechanism 6 includes a sleeve 61 coaxially sleeved with the shaft 31, and a plurality of blades 62 are fixedly connected to the outer wall of the sleeve 61. The blades 62 are provided with grooves 63 that are adapted to the annular protrusions 5. Specifically, the material-diverting mechanism 6 realizes coaxial rotation with the rotating shaft 31 through the sleeve 61 to ensure that the driven member 4 is synchronously driven to rotate, but the shaft 31 can be lifted and lowered in the sleeve 61 to realize the up and down movement of the air guide plate 32. A plurality of blades 62 are annularly distributed on the outer sleeve 61 and extend to a position close to the bottom wall of the drying tower 1. The grooves 63 on the outer side of the blades 62 are for cooperating with the annular protrusions 5 on the funnel wall of the drying tower 1. On the one hand, when the blades 62 rotate, the accumulated The aggregated materials are subjected to a strong shearing effect to break up the lumps. On the other hand, the up and down movement of the material-dispensing mechanism 6 can be limited by the position limit of the annular protrusion 5, ensuring that the vibration component 7 can stably and effectively act on the lifting and lowering air guide mechanism 3 to prevent incompletely dried materials from adhering to its surface. Moreover, since the gap between the blade 62 and the protrusion is very small and the shape is special, the airflow and powder circulation at the bottom of the tower can be accelerated during rotation, so that the accelerated rising gas rushes to the bottom surface of the air guide plate 32, and then the airflow direction is changed through the guide plate to diffuse it to the tower wall of the drying tower 1, thereby preventing dead zone and wall adhesion at the bottom of the tower, promoting secondary dispersion of powder and strengthening the bottom airflow circulation, so that the material can be fully dried and not easily adhered to the tower wall of the drying tower 1.

[0053] When the cam 71 is in the state of being rotated at a high speed with respect to the gear 32, the cam 71 is in the state of being rotated at a high speed with respect to the gear 32. The elastic force is tightly pressed on the abutment teeth 37 in the keyway 36. As the shaft rod 31 rotates, when the shaft rod 31 is forced to rise or fall, the end of the abutment rod 71 will continuously slide over each abutment tooth 37 in the keyway 36, and the abutment teeth 37 will generate an outward squeezing force on the abutment rod 71. At the same time, the compressed elastic member releases energy during the continuous lifting process, pushing the abutment rod 71 to rebound in the direction of the keyway 36 and contact the next abutment tooth 37, forming a continuous impact on the shaft rod 31, allowing this vibration energy to be transmitted to the sleeve 61 thereon through the abutment rod 71, and then to the entire material dispensing mechanism 6 and the shaft rod 31. This high-frequency vibration significantly reduces the adhesion of fine powder to the surfaces of the blades 62, the shaft rod 31 and the air guide plate 32, effectively preventing scaling, and at the same time further loosening the powder in the contact area at the bottom of the tower, assisting the material dispensing and gas lifting functions.

[0054] In a further embodiment of the present invention, the two sides of the blade 62 are fixedly connected with the air deflector 64, and the other end of the abutment rod 71 is symmetrically fixedly connected with the air pusher plate 72 located in each air deflector 64. Specifically, the air deflector 64 is connected to the windward side and the leeward side of the blade 62, and its shape is a cover-like structure with openings on both sides, forming a semi-closed or partially constrained space, similar to a micro air duct, and the air pusher plate 72 is rigidly connected to the outer end of the abutment rod 71, that is, the end away from the key slot 36. When the abutment rod 71 is laterally displaced under the action of the vibration component 7, the air pusher plate 72 is also synchronously moved high inside the air deflector 64. The high-frequency reciprocating motion inside and outside is equivalent to adding a high-frequency fan blade in the local air flow channel of the air guide hood 64. The reciprocating motion of the air pusher plate 72 inside and outside will periodically compress and expand the volume of the chamber formed by it and the inner wall of the air guide hood 64, thereby generating a strong, small pulse airflow with a frequency consistent with that of the vibration component 7 inside the air guide hood 64. This pulse airflow can, on the one hand, more thoroughly remove the materials adhering to the blade 62 and the surrounding area, and on the other hand, the pulse airflow disturbance is superimposed on the stable airflow generated by the rotation of the blade 62, which greatly enhances the local turbulence intensity and improves the powder dispersion efficiency and gas-solid heat and mass transfer rate in this area.

[0055] In a further embodiment of the present invention, a discharge port 101 is provided at the bottom of the drying tower 1. A discharge tray 8 is fixedly connected to the shaft 31. The discharge tray 8 is located below the discharge port 101. Specifically, the discharge port 101 is the outlet for the finished powder to finally leave the drying tower 1. They are distributed in an annular manner at the bottom of the drying tower 1 funnel. The discharge tray 8 is fixedly mounted on the rotating shaft 31. Its position is below the discharge port 101 and close to the tower bottom outlet area. Under the action of the rotating centrifugal force, the powder settles or gathers on the discharge tray 8 after drying. The powder on the surface is thrown outwards. At the same time, the airflow thrown out by the discharge tray 8 can also help guide the falling powder to flow to the discharge port 101. The discharge tray 8 can also rise and fall together with the shaft 31, allowing the discharge tray 8 to move up and down in the area of ​​the discharge port 101, playing a role in guiding and assisting unloading. When the material falls to the discharge tray 8, the rotating discharge tray 8 spreads it evenly around and throws it to the area of ​​the annular discharge port 101, which helps to discharge the material evenly and continuously, and prevents the powder from accumulating above the discharge port or bridging blockage.

[0056] In a further embodiment of the present invention, an annular collecting net 9 is installed on the top of the inner wall of the drying tower 1, and a plurality of heat conducting sheets 91 are provided on the top surface of the annular collecting net 9. Specifically, due to the drying process, especially when processing fine powders, a portion of extremely fine dust will follow the rising air flow to the top area of ​​the drying tower 1. The annular collecting net 9 has a small aperture and can intercept these ultrafine material particles that have not been fully dried or have too small a particle size to be completely settled, thereby preventing them from entering the exhaust pipe and causing loss and waste. The core function of the plurality of heat conducting sheets 91 is to collect excess heat in the drying tower 1 and to collect the excess heat on the annular collecting net 9. Continuous and uniform heating is carried out to maintain its temperature higher than the dew point temperature of the surrounding gas. During the operation of the annular capture net 9, its surface is kept in a sufficiently dry and hot state, which significantly reduces the risk of condensation on the surface of the capture net. If condensation occurs on the surface of the capture net, once the fine powder adheres, it is very easy to harden into muddy dirt, which quickly blocks the mesh and causes failure. Heating maintains its "dry and hot" state, effectively preventing condensation. At the same time, it can allow the internal airflow to circulate through the annular fighting net, absorbing the heat stored in the heat conducting plate 91, so that the overall temperature of the vortex generated by the movement of the lifting air guide mechanism 3 is more uniform.

[0057] The above description is merely illustrative of certain exemplary embodiments of the present invention. It goes without saying that those skilled in the art will be able to modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and description are illustrative in nature and should not be construed as limiting the scope of protection of the claims.

Claims

1. A method for preparing silicon dioxide for vitamin carrier, characterized in that: The steps include: S1. Prepare a sodium silicate solution with a mass concentration of 15-20% by weight of solid sodium silicate having a modulus of 3.0-3.5, add polyaluminium chloride and chitosan composite flocculant with a mass concentration of 0.5-1.0%, stir at 80-100 r / min for 60 min, and let stand for 60 min to obtain a high-purity sodium silicate solution; S2, adding alkylphenol polyoxyethylene ether to the obtained solution, and preparing a sulfuric acid solution with a mass concentration of 10-15%; S3. Add industrial water to the reactor to a volume ratio of 1 / 6, heat to 30-40°C, add the sodium silicate solution from step 2, and stir at 60-80 rpm; S4. Raise the temperature to 45-55°C, adjust the stirring rate to 80-100 r / min, and simultaneously add sodium silicate solution and sulfuric acid solution dropwise until the volume of the reaction system accounts for 40% of the kettle volume. Control the pH to 7.5-8.5, react for 60 minutes, continue to add sulfuric acid solution dropwise until the pH is 4.5-5.5, and age for 30 minutes; S5. After filtration, the filter cake is washed with industrial water. The sodium sulfate content of the finished product is controlled to be less than 2% by the conductivity of the washing water. The solid content of the filter cake is adjusted to 20-25% before beating; S5. The concentrated slurry is sent to a spray dryer for drying, using hot air from natural gas combustion as a heat source to obtain granular silicon dioxide.

2. The method for preparing silicon dioxide for vitamin carrier according to claim 1, characterized in that: The composite flocculant is composed of polyaluminium chloride and chitosan, and the added amount is 0.5-1.0% of the total mass of the sodium silicate solution. During the stirring process, heavy metals and impurities are removed simultaneously.

3. A system for preparing silicon dioxide for use as a vitamin carrier for implementing the preparation method according to any one of claims 1 to 2, comprising a drying tower (1) and an atomizing nozzle (2) installed on the drying tower (1), characterized in that: Also includes: A lifting air guide mechanism (3) is installed inside the drying tower (1), and a driving member (4) for driving the lifting air guide mechanism (3) to rotate is installed at the bottom of the drying tower (1); The bottom of the drying tower (1) is funnel-shaped and is provided with a plurality of annular protrusions (5) distributed along the discharge direction. The lifting air guide mechanism (3) is externally connected to a material shifting mechanism (6) that rotates coaxially with the lifting air guide mechanism (3). The material shifting mechanism (6) is clearance-matched with the annular protrusions (5). A vibration component (7) that abuts against the lifting flow pushing mechanism (3) is installed in the material shifting mechanism (6). When the hot air enters the drying tower (1), the driving member (4) drives the lifting and pushing mechanism (3) to push the hot air upward, and drives the material-dispensing mechanism (6) to rotate so that the airflow at the bottom of the drying tower (1) is accelerated to blow toward the lifting and guiding mechanism (3) and diffuse to the inner wall of the drying tower (1).

4. The system for preparing silicon dioxide for vitamin carrier according to claim 3, characterized in that: The driving member (4) includes a driving motor (41) fixed to the bottom of the drying tower (1); an output shaft of the driving motor (41) is installed with a connecting shaft sleeve (42) in the drying tower (1); and the bottom of the lifting air guide mechanism (3) is movably inserted in the connecting shaft sleeve (42).

5. The system for preparing silicon dioxide for vitamin carrier according to claim 4, characterized in that: The lifting air guide mechanism (3) includes a shaft (31) inserted into a connecting shaft sleeve (42), the top of the shaft (31) is fixedly connected to an air guide plate (32), the air guide plate (32) is located below the atomizing nozzle (2), the bottom of the shaft (31) is fixedly connected to an abutting cross bar (33), and a guide ring (34) for overlapping the abutting cross bar (33) is fixedly connected inside the drying tower (1), and a plurality of arc-shaped grooves (35) are distributed in an annular manner on the guide ring (34).

6. The system for preparing silicon dioxide for vitamin carrier according to claim 5, characterized in that: The material-dispensing mechanism (6) comprises a sleeve (61) coaxially sleeved with the shaft (31), a plurality of blades (62) being fixedly connected to the outer wall of the sleeve (61), and a groove (63) adapted to the annular protrusion (5) is formed on the blades (62).

7. The system for preparing silicon dioxide for vitamin carrier according to claim 6, characterized in that: The vibration assembly (7) comprises a pair of abutment rods (71) elastically inserted into the sleeve (61), key slots (36) are vertically provided on both sides of the shaft rod (31), abutment teeth (37) are provided in the key slots (36), and one end of the abutment rod (71) extends into the key slot (36) and abuts against the abutment teeth (37).

8. The system for preparing silicon dioxide for vitamin carrier according to claim 7, characterized in that: The two sides of the blade (62) are respectively fixedly connected to the air guide covers (64), and the other end of the abutting rod (71) is symmetrically fixedly connected to the air pushing plates (72) respectively located in the air guide covers (64).

9. The system for preparing silicon dioxide for vitamin carrier according to claim 5, characterized in that: The bottom of the drying tower (1) is provided with an annularly distributed discharge port (101), and a discharge tray (8) is fixedly connected to the shaft (31), and the discharge tray (8) is located below the discharge port (101).

10. The system for preparing silicon dioxide for vitamin carrier according to claim 3, characterized in that: An annular collecting net (9) is installed on the top of the inner wall of the drying tower (1), and a plurality of heat conducting sheets (91) are provided on the top surface of the annular collecting net (9).

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