Freeze drying device for preparing heavy calcium carbonate and preparation method

Abstract

The embodiment of the invention provides a freeze drying device for preparing ground calcium carbonate and a preparation method, and relates to the technical field of food additives. The freeze-drying device for preparing the ground calcium carbonate comprises a drying chamber, and the drying chamber is a sealed container and used for containing particle materials to be dried; the refrigerating system is used for freezing the particle materials to be below the freezing point, so that water in the materials forms ice crystals; the vacuum system is used for forming a vacuum environment in the drying chamber to directly sublimate ice crystals; the heating system is arranged inside or outside the drying chamber and is used for providing heat required by sublimation of ice crystals; the material dispersing mechanism is arranged in the drying chamber and used for keeping the particle materials in a dispersed state in the drying process. The damage of high temperature to active groups such as hydroxyl on the surface of calcium carbonate is avoided through low-temperature treatment, so that the calcium carbonate can be chemically bonded with a matrix more easily in composite materials such as plastic and rubber, and the reinforcing effect is improved.

Description

Technical Field

[0001] This application relates to the technical field of food additives, and more specifically, to a freeze-drying device and a preparation method for preparing heavy calcium carbonate. Background Art

[0002] In the related art, food-grade heavy calcium carbonate products need to remove moisture through a drying process; in traditional drying methods, such as hot air drying, spray drying, etc., during the evaporation of moisture, the surface tension of liquid water will cause particles to aggregate and agglomerate with each other, thereby changing the original particle size and dispersion state of the particles. This not only affects the physical and chemical properties of the product, but may also reduce its usability and application value; However, if particle aggregation occurs during the drying process, it will lead to unstable performance of the drug carrier and even loss of application value. Summary of the Invention

[0003] This application aims to solve at least one of the technical problems existing in the prior art. For this purpose, this application proposes a freeze-drying device and a preparation method for preparing heavy calcium carbonate.

[0004] In a first aspect, a freeze-drying device for preparing heavy calcium carbonate provided by an embodiment of the present invention includes a drying chamber, the drying chamber is a sealed container for accommodating particulate materials to be dried; a refrigeration system is connected to the drying chamber for freezing the particulate materials below the freezing point so that the moisture in the materials forms ice crystals; a vacuum system is connected to the drying chamber for creating a vacuum environment in the drying chamber so that the ice crystals directly sublimate; a heating system is arranged inside or outside the drying chamber for providing the heat required for the sublimation of the ice crystals; a material dispersion mechanism is arranged in the drying chamber for keeping the particulate materials in a dispersed state during the drying process.

[0005] According to the freeze-drying device for preparing heavy calcium carbonate of the embodiment of this application, through vacuum freeze-drying technology, the moisture is directly removed by the sublimation of ice crystals, avoiding the influence of the surface tension of liquid water, and effectively maintaining the original particle size and uniform dispersion of the particles. By using vacuum freeze-drying, the moisture can be directly removed by the sublimation of ice crystals, avoiding particle aggregation caused by the surface tension of liquid water, and maintaining the original particle size and uniform dispersion. Since vacuum freeze-drying directly sublimes the moisture in calcium carbonate from a solid state to a gaseous state, it will maintain the porous structure on the surface of calcium carbonate, increasing its pore volume and specific surface area. The low-temperature treatment avoids the destruction of active groups such as surface hydroxyl groups of calcium carbonate at high temperature, making it easier to form chemical bonds with the matrix in composite plastics and rubbers, and enhancing the enhancement effect.

[0006] The provided temperature sensor and pressure sensor are respectively used to monitor the temperature and pressure inside the drying chamber, so as to control the drying process in real time. When the preset values are exceeded, the controller drives the audible and visual alarm to give an alarm, providing safety protection and realizing the automatic control of parameters. The structure is simple and has strong applicability.

[0007] In addition, the freeze-drying device for preparing heavy calcium carbonate according to the embodiment of the present application further has the following additional technical features: In a preferred embodiment of the present invention, a temperature sensor and a pressure sensor are further provided inside the drying chamber, which are respectively used to monitor the temperature and pressure inside the drying chamber, so as to control the drying process in real time.

[0008] In a preferred embodiment of the present invention, the refrigeration system includes a compressor, a condenser, an evaporator, and a throttling device. The refrigeration of the drying chamber is achieved through the cyclic flow of the refrigerant, and the granular material is frozen below the freezing point, causing the moisture in the material to form ice crystals.

[0009] In a preferred embodiment of the present invention, the vacuum system includes a vacuum pump and a vacuum pipeline. The vacuum pump is connected to the drying chamber through the vacuum pipeline and is used to extract the gas inside the drying chamber to form a vacuum environment, enabling the ice crystals to directly sublimate into water vapor.

[0010] In a preferred embodiment of the present invention, the heating system includes a heating element and a temperature controller. The heating element is arranged inside the drying chamber, and the temperature controller is used to control the heating power of the heating element to maintain the temperature stability inside the drying chamber, provide heat for the sublimation of ice crystals, and maintain the progress of the sublimation process.

[0011] In a preferred embodiment of the present invention, the material dispersion mechanism is arranged inside the drying chamber and includes a rotating disk and a vibration device. The rotating disk is arranged at the bottom of the drying chamber, and the vibration device is connected to the rotating disk and is used to make the rotating disk vibrate. An ultrasonic generator is arranged at the bottom of the drying chamber and is used to emit ultrasonic waves to the granular material to promote the dispersion of the particles.

[0012] Since the rotating disk is arranged inside the drying chamber, when loading and unloading materials on the surface of the rotating disk, the rotating disk needs to be taken out of the drying chamber, which is cumbersome to operate and inconvenient to hold. Therefore, the working process of the freeze-drying device for preparing heavy calcium carbonate according to the embodiment of the present application is described below with reference to the accompanying drawings: In a preferred embodiment of the present invention, the drying chamber includes a housing and a bottom cover. The rotating disk is rotatably installed on the surface of the bottom cover, and a sealing ring is fixed at the edge of the bottom cover. The sealing ring is in sealed contact with the edge of the lower port of the housing. The sealing ring has a shock-absorbing and isolating effect.

[0013] It also includes a support frame, which includes a base and a lifting column. The lower end of the lifting column is fixedly connected to the base, the bottom cover is installed on the surface of the base, and the upper end of the lifting column is connected to the shell for driving the shell to rise and fall.

[0014] In a preferred embodiment of the present invention, a reduction motor is fixed at the bottom of the bottom cover, and the reduction motor is connected to the rotating disk through a coupling, and the outer diameter of the rotating disk is smaller than the inner diameter of the outer shell; the coupling is an isolation type magnetic coupling, which effectively isolates the surface of the bottom cover so that the internal chamber of the outer shell is in a sealed state.

[0015] The lower end of the shell is snap-fitted with the bottom cover to form a sealed space in the internal drying chamber, which is convenient for vacuum cooling treatment, and a shock absorber is installed between the bottom cover and the base to play a shock-absorbing role. The joint between the upper end of the bottom cover and the shell is sealed by a sealing ring to ensure the airtightness of the internal chamber. The shell is driven upward by the lifting column to be separated from the bottom cover, which is convenient for taking and placing materials on the rotating disk installed on the bottom cover, and the operation is convenient.

[0016] In a preferred embodiment of the present invention, a shock absorber for supporting the bottom cover is installed on the surface of the base, the upper end of the shock absorber is fixed to the bottom cover, and the lower end of the shock absorber is fixed to the base, and multiple shock absorbers are provided, and multiple shock absorbers are distributed in a ring on the edge of the bottom cover.

[0017] In a preferred embodiment of the present invention, the lifting column includes a column and a sliding sleeve, the lower end of the column is fixed to the base, the sliding sleeve is slidably mounted on the upper end of the column, the side wall of the shell is fixedly connected to the sliding sleeve via a connecting rod, the sliding sleeve has an electric push rod built in, and the movable end of the electric push rod is connected to the column.

[0018] The material inside the rotating disk is unevenly distributed, resulting in uneven thickness of the accumulated material. The thicker part is heated slowly and unevenly, which affects the freezing sublimation efficiency. For this reason, the working process of the freeze-drying device for preparing heavy calcium carbonate according to the embodiment of the present application is described below with reference to the accompanying drawings: In a preferred embodiment of the present invention, a support rod is fixed in the drying chamber, a scraper is slidably connected to the support rod, the lower end of the scraper is toothed, a connecting rod is hinged at one end of the scraper, a disc is rotatably mounted on the support rod, an eccentric shaft is fixed to the disc, the other end of the connecting rod is rotatably connected to the eccentric shaft, a rotating wheel is coaxially fixed to the disc, and the edge of the rotating wheel is drivingly connected to the edge of the rotating disc; the scraper is made of heat-conducting material.

[0019] During the self-rotation of the rotating disk, the scraper levels the materials inside the rotating disk. At the same time, the scraper is made of a heat-conducting material, and the part of its lower end in contact with the materials effectively conducts heat, enabling the bottom of the materials to dissipate heat evenly and cool down. The scraper is designed with teeth, which increases the surface area of the scraped materials and has a better heat dissipation effect. The rotation of the rotating disk drives the rolling of the rotating wheel, causing the rotating wheel to drive the rotation of the disk. The disk is pulled by the eccentric shaft to move back and forth at one end of the connecting rod, causing the scraper to slide back and forth in the chute, repeatedly changing the scraping position of the materials, so that the materials are fully lifted, improving the flatness and the uniformity of heat reception.

[0020] In a preferred embodiment of the present invention, the support rod is provided with a chute, which is opened along the length direction of the support rod. The scraper is slidably inserted into the chute. The support rod is rotatably installed with a rotating rod, and the disk is coaxially fixed to the upper end of the rotating rod, and the rotating wheel is coaxially fixed to the lower end of the rotating rod.

[0021] Therefore, the working process of the freeze-drying device for preparing heavy calcium carbonate according to the embodiment of the present application is described below with reference to the accompanying drawings: In a preferred embodiment of the present invention, the rotating disk and the bottom cover are coaxially arranged. The outer surface of the housing is provided with an observation window, a pressure relief valve is installed at the top of the housing, and a control panel is installed on the surface of the sliding sleeve.

[0022] In a preferred embodiment of the present invention, the surface of the base is provided with a clamping groove, and a sliding plate is slidably clamped in the clamping groove, and the bottom cover is arranged on the surface of the sliding plate.

[0023] An observation window is opened on the surface of the housing to facilitate real-time observation of the internal material processing situation, and a pressure relief valve is installed at the top of the housing to prevent the pressure from exceeding the preset value and damaging the equipment. By installing a slidable sliding plate on the surface of the base, it is convenient to pull the bottom cover to slide, facilitating the replacement of the materials inside the rotating disk, and the operation is convenient.

[0024] In a second aspect, the embodiment of the present invention further provides a method for preparing heavy calcium carbonate, including the freeze-drying device for preparing heavy calcium carbonate described in any one of the above; and the following steps: S1. Raw material screening: Select limestone with a calcium oxide content of more than 54% as the production raw material; S2. Raw material crushing: Crush the obtained calcium oxide; S3. Stirring and pulping: Place the crushed raw materials in a stirring container and stir with water to make them evenly mixed; S4. Grinding and demagnetization: Wet grinding and wet demagnetization are carried out to remove the magnetic substances brought by the raw materials and equipment wear during the crushing process, improve the purity, and reduce the influence of foreign substances on the whiteness of the product; S5, Dehydration treatment: Vacuum freeze drying is used to dehydrate and dry the material after S4 treatment; S6, Crushing.

[0025] In a preferred embodiment of the present invention, during S2, coarse crushing is first performed, followed by fine crushing, and a grinding aid is added to improve the crushing efficiency and reduce energy consumption.

[0026] In a preferred embodiment of the present invention, during S2, the finely crushed raw materials are classified, and the raw materials that do not meet the classification requirements are introduced into S2 for fine crushing treatment.

[0027] In a preferred embodiment of the present invention, an appropriate amount of dispersant is added during S3 to prevent agglomeration.

[0028] Additional aspects and advantages of the present application will be given in part in the following description, will become apparent in part from the following description, or will be understood through the practice of the present application. Brief Description of the Drawings

[0029] To more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required to be used in the embodiments of the present application. It should be understood that the following drawings only show certain embodiments of the present application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0030] Figure 1 is a schematic three-dimensional structure diagram of a freeze-drying device for the preparation of heavy calcium carbonate according to an embodiment of the present application; Figure 2 is a schematic internal structure diagram of a drying chamber according to an embodiment of the present application; Figure 3 is a schematic three-dimensional structure diagram of a bottom cover according to an embodiment of the present application; Figure 4 is a schematic three-dimensional structure diagram of the drying chamber in an open state according to an embodiment of the present application; Figure 5 is a schematic three-dimensional structure diagram of a base according to an embodiment of the present application; Figure 6 is a schematic three-dimensional structure diagram of a support rod according to an embodiment of the present application; Figure 7 is a schematic three-dimensional structure diagram of a scraper according to an embodiment of the present application; Figure 8 is a flowchart of the preparation method of heavy calcium carbonate according to an embodiment of the present application.

[0031] Icons: 100, drying chamber; 101, temperature sensor; 102, pressure sensor; 110, housing; 111, observation window; 120, bottom cover; 121, sealing ring; 200, refrigeration system; 300, vacuum system; 310, vacuum pump; 320, vacuum pipeline; 400, heating system; 410, heating element; 420, temperature controller; 500, material dispersion mechanism; 510, rotating disk; 520, vibration device; 530, reduction motor; 600, support frame; 610, base; 611, clamping groove; 620, lifting column; 621, column; 622, sliding sleeve; 623, electric push rod; 630, shock absorber; 640, sliding plate; 700, support rod; 701, chute; 710, scraper; 720, connecting rod; 730, disk; 731, eccentric shaft; 740, rotating rod; 750, rotating wheel. Detailed implementation manners

[0032] The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings in the embodiments of the present application.

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Apparently, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0034] Embodiment The freeze-drying device and preparation method for preparing heavy calcium carbonate according to the embodiments of the present application will be described below with reference to the accompanying drawings; As Figures 1 - 7 shown, for the freeze-drying device for preparing heavy calcium carbonate according to the embodiments of the present application, in the first aspect, a freeze-drying device for preparing heavy calcium carbonate provided by an embodiment of the present invention includes a drying chamber 100. The drying chamber 100 is a sealed container for accommodating particulate materials to be dried. The refrigeration system 200 is connected to the drying chamber 100 and is used to freeze the particulate materials below the freezing point so that the moisture in the materials forms ice crystals. The vacuum system 300 is connected to the drying chamber 100 and is used to create a vacuum environment in the drying chamber 100 so that the ice crystals directly sublimate. The heating system 400 is arranged inside or outside the drying chamber 100 and is used to provide the heat required for the sublimation of the ice crystals. The material dispersion mechanism 500 is arranged in the drying chamber 100 and is used to keep the particulate materials in a dispersed state during the drying process.

[0035] The freeze-drying device for preparing heavy calcium carbonate according to the embodiments of the present application uses the vacuum freeze-drying technology to directly remove moisture by the sublimation of ice crystals, avoiding the influence of the surface tension of liquid water and effectively maintaining the original particle size and uniform dispersion of the particles. By using vacuum freeze-drying, moisture can be directly removed by the sublimation of ice crystals, avoiding particle aggregation caused by the surface tension of liquid water and maintaining the original particle size and uniform dispersion. Since vacuum freeze-drying directly sublimes the moisture in calcium carbonate from the solid state to the gaseous state, it will maintain the porous structure on the surface of calcium carbonate, increasing its pore volume and specific surface area. The low-temperature treatment avoids the damage of high temperature to active groups such as hydroxyl groups on the surface of calcium carbonate, making it easier to form chemical bonds with the matrix in composite plastics and rubbers and enhancing the strengthening effect.

[0036] The temperature sensor 101 and the pressure sensor 102 are provided to monitor the temperature and pressure in the drying chamber 100 respectively, so as to control the drying process in real time. When the preset value is exceeded, the controller drives the sound and light alarm to give an alarm, playing a role in safety protection and realizing the automatic control of parameters. The structure is simple and the applicability is strong.

[0037] In addition, the freeze-drying device for preparing heavy calcium carbonate according to the embodiments of the present application also has the following additional technical features: In a specific embodiment of the present invention, a temperature sensor 101 and a pressure sensor 102 are further provided in the drying chamber 100, which are respectively used to monitor the temperature and pressure in the drying chamber 100 so as to control the drying process in real time.

[0038] In a specific embodiment of the present invention, the refrigeration system 200 includes a compressor, a condenser, an evaporator and a throttling device, and realizes the refrigeration of the drying chamber 100 through the circulating flow of the refrigerant, freezing the particulate material below the freezing point and forming ice crystals in the material.

[0039] In a specific embodiment of the present invention, the vacuum system 300 includes a vacuum pump 310 and a vacuum pipeline 320. The vacuum pump 310 is connected to the drying chamber 100 through the vacuum pipeline 320 and is used to extract the gas in the drying chamber 100 to form a vacuum environment, enabling the ice crystals to directly sublime into water vapor.

[0040] In a specific embodiment of the present invention, the heating system 400 includes a heating element 410 and a temperature controller 420. The heating element 410 is arranged inside the drying chamber 100, and the temperature controller 420 is used to control the heating power of the heating element 410 to maintain the temperature stability in the drying chamber 100, provide heat for the sublimation of ice crystals, and maintain the progress of the sublimation process.

[0041] In a specific embodiment of the present invention, the material dispersion mechanism 500 is disposed within the drying chamber 100 and includes a rotating disk 510 and a vibration device 520; the rotating disk 510 is disposed at the bottom of the drying chamber 100, and the vibration device 520 is connected to the rotating disk 510 for vibrating the rotating disk 510. An ultrasonic generator is disposed at the bottom of the drying chamber 100 for emitting ultrasonic waves to the particulate material to promote the dispersion of the particles.

[0042] Since the rotating disk 510 is disposed within the drying chamber 100, discharging and feeding materials onto the surface of the rotating disk 510 both require taking out the rotating disk 510 from the drying chamber 100, which is cumbersome in operation and inconvenient to hold. Therefore, the working process of the freeze-drying device for preparing heavy calcium carbonate according to an embodiment of the present application is described below with reference to the accompanying drawings: As Figures 1 - 5 shown, in a specific embodiment of the present invention, the drying chamber 100 includes a housing 110 and a bottom cover 120. The rotating disk 510 is rotatably mounted on the surface of the bottom cover 120. A sealing ring 121 is fixed to the edge of the bottom cover 120, and the sealing ring 121 is in sealing contact with the edge of the lower port of the housing 110; the sealing ring 121 has a shock-absorbing and isolating function.

[0043] It further includes a support frame 600. The support frame 600 includes a base 610 and a lifting column 620. The lower end of the lifting column 620 is fixedly connected to the base 610. The bottom cover 120 is mounted on the surface of the base 610. The upper end of the lifting column 620 is connected to the housing 110 for driving the housing 110 to lift.

[0044] In a specific embodiment of the present invention, a reduction motor 530 is fixed to the bottom of the bottom cover 120. The reduction motor 530 is in transmission connection with the rotating disk 510 through a coupling. The outer diameter of the rotating disk 510 is smaller than the inner diameter of the housing 110; the coupling is an isolation type magnetic coupling, effectively isolating the surface of the bottom cover 120, so that the inner chamber of the housing 110 is in a sealed state.

[0045] In a specific embodiment of the present invention, shock absorbers 630 for supporting the bottom cover 120 are mounted on the surface of the base 610. The upper end of the shock absorber 630 is fixed to the bottom cover 120, and the lower end of the shock absorber 630 is fixed to the base 610. A plurality of shock absorbers 630 are provided, and the plurality of shock absorbers 630 are annularly distributed at the edge of the bottom cover 120.

[0046] The lower end of the outer shell 110 is engaged and clamped with the bottom cover 120 to form a sealed space for the internal drying chamber 100, facilitating vacuum cooling treatment. A shock absorber 630 is installed between the bottom cover 120 and the base 610 to play a shock-absorbing role. The sealing ring 121 is provided to seal the docking part between the upper end of the bottom cover 120 and the outer shell 110, ensuring the airtightness of the internal chamber. The lifting column 620 drives the outer shell 110 to move upward, separating it from the bottom cover 120, facilitating the loading and unloading operations of the rotating disk 510 installed on the bottom cover 120, and the operation is convenient.

[0047] In a specific embodiment of the present invention, the lifting column 620 includes a column 621 and a sliding sleeve 622. The lower end of the column 621 is fixed to the base 610. The sliding sleeve 622 is slidably sleeved on the upper end of the column 621. The side wall of the outer shell 110 is fixedly connected to the sliding sleeve 622 through a connecting rod. An electric push rod 623 is built in the sliding sleeve 622, and the movable end of the electric push rod 623 is connected to the column 621.

[0048] The materials distributed in the rotating disk 510 are uneven, resulting in different thicknesses of the piled materials. The thicker parts are slow to heat and unevenly heated, affecting the freeze-drying efficiency. Therefore, the working process of the freeze-drying device for preparing heavy calcium carbonate according to the embodiments of the present application is described below with reference to the accompanying drawings: As Figure 2 、 6 As shown in Fig. -7, in a specific embodiment of the present invention, a support rod 700 is fixed in the drying chamber 100. A scraper 710 is slidably connected to the support rod 700. The lower end of the scraper 710 is tooth-shaped. One end of the scraper 710 is hinged to a connecting rod 720. A disk 730 is rotatably installed on the support rod 700. An eccentric shaft 731 is fixed to the disk 730. The other end of the connecting rod 720 is rotatably connected to the eccentric shaft 731. A rotating wheel 750 is coaxially fixed to the disk 730. The edge of the rotating wheel 750 is in rolling contact with the edge of the rotating disk 510; the scraper 710 is made of a heat-conducting material.

[0049] During the rotation of the rotating disk 510, the scraper 710 levels the materials in the rotating disk 510. At the same time, the scraper of the scraper 710 is made of a heat-conducting material, and the part in contact with the materials at its lower end effectively conducts heat, enabling the bottom of the materials to dissipate heat evenly. The scraper 710 is designed with a tooth shape, increasing the surface area of the scraped materials and having a better heat dissipation effect; the rotation of the rotating disk 510 drives the rotating wheel 750 to roll, causing the rotating wheel 750 to drive the disk 730 to rotate. The disk 730 pulls one end of the connecting rod 720 to move back and forth through the eccentric shaft 731, causing the scraper 710 to slide back and forth in the chute 701, repeatedly changing the leveling position of the materials, so that the materials are fully scraped up, improving the flatness and the evenness of heat reception.

[0050] In a specific embodiment of the present invention, a chute 701 is formed in the support rod 700. The chute 701 is formed along the length direction of the support rod 700. The scraping plate 710 is slidably inserted into the chute 701. A rotating rod 740 is rotatably installed on the support rod 700. A disc 730 is coaxially fixed to the upper end of the rotating rod 740. A rotating wheel 750 is coaxially fixed to the lower end of the rotating rod 740.

[0051] Since the bottom cover 120 is disposed directly below the outer shell 110, it is not convenient to take and place the materials in the rotating disc 510. Therefore, the working process of the freeze-drying device for preparing heavy calcium carbonate according to the embodiment of the present application will be described below with reference to the accompanying drawings: In a specific embodiment of the present invention, the rotating disc 510 and the bottom cover 120 are coaxially arranged. An observation window 111 is formed on the outer surface of the outer shell 110. A pressure relief valve is installed at the top of the outer shell 110. A control panel is installed on the surface of the sliding sleeve 622.

[0052] In a specific embodiment of the present invention, a clamping groove 611 is formed on the surface of the base 610. A sliding plate 640 is slidably clamped in the clamping groove 611. The bottom cover 120 is disposed on the surface of the sliding plate 640.

[0053] An observation window 111 is formed on the surface of the outer shell 110, which is convenient for observing the internal material processing situation in real time. A pressure relief valve is installed at the top of the outer shell 110 to prevent the pressure from exceeding the preset value and damaging the equipment. By installing a slidable sliding plate 640 on the surface of the base 610, it is convenient to pull the bottom cover 120 to slide, which is convenient for replacing the materials in the rotating disc 510, and the operation is convenient.

[0054] Please refer to Figure 8 , Another embodiment of the present invention further provides a method for preparing heavy calcium carbonate, including the freeze-drying device for preparing heavy calcium carbonate described in any one of the above; and the following steps: S1. Raw material screening: Select limestone with a calcium oxide content of more than 54% as the production raw material; S2. Raw material crushing: Crush the obtained calcium oxide; S3. Stirring and pulping: Place the crushed raw materials in a stirring container and stir with water to make the mixture uniform; S4. Grinding and demagnetization: Wet grinding and wet demagnetization are carried out to remove the magnetic substances brought by the raw materials and equipment wear during the crushing process, improve the purity, and reduce the influence of foreign substances on the whiteness of the product; S5. Dehydration treatment: Vacuum freeze-drying is used to dehydrate and dry the materials treated in S4; S6. Crushing.

[0055] In a specific embodiment of the present invention, in the process of S2, coarse crushing is first carried out, then fine crushing is carried out, and a grinding aid is added to improve the crushing efficiency and reduce energy consumption.

[0056] In a specific embodiment of the present invention, in S2, the raw materials after fine crushing are classified, and the raw materials that do not meet the classification requirements are introduced into S2 for fine crushing treatment.

[0057] In a specific embodiment of the present invention, an appropriate amount of dispersant is added in S3 to prevent agglomeration.

[0058] In actual operation, the specific steps are as follows: The particulate material to be dried is evenly distributed on the rotating disk 510 of the drying chamber 100; Start the refrigeration system 200, lower the temperature in the drying chamber 100 below the freezing point (for example, -30°C to -50°C), so that the moisture in the particulate material forms ice crystals; Start the vacuum system 300, lower the pressure in the drying chamber 100 below the triple point pressure of the ice crystal (for example, 10-3 to 10-2 Pa), so that the ice crystal directly sublimes into water vapor; Start the heating system 400, control the heating power of the heating element 410 through the temperature controller 420, provide heat for the sublimation of the ice crystal, and maintain the sublimation process; Start the material dispersion mechanism 500, the rotating disk 510 rotates at a certain speed (for example, 5-10 rpm), at the same time the vibration device 520 makes the rotating disk 510 vibrate, and the ultrasonic generator emits ultrasonic waves (for example, 20-40 kHz), so that the particulate material remains in a dispersed state during the drying process and avoids particle aggregation; When the ice crystal is completely sublimated, turn off the heating system 400, the vacuum system 300 and the refrigeration system 200, and take out the dried particulate material.

[0059] According to the properties and drying requirements of the particulate material, adjust the refrigeration temperature of the refrigeration system 200, the vacuum degree of the vacuum system 300, the heating power of the heating system 400 and the operating parameters of the material dispersion mechanism 500 to obtain the best drying effect and particle dispersion state.

[0060] Wet magnetic separation can remove magnetic substances (such as iron) in limestone; it can also remove magnetic substances brought in by equipment wear during the deep processing of limestone, and reduce the impact of deep processing on the whiteness of the product; In the process of vacuum freeze-drying, the moisture in the material is first frozen into ice crystals, and then directly heated and sublimated into water vapor in a vacuum environment. Since there is no surface tension of liquid water during the sublimation process of the ice crystal, it will not cause aggregation and agglomeration between particles, so that the original particle size and uniform dispersion state of the particles can be perfectly maintained.

[0061] The setting of the material dispersion mechanism 500 further ensures the dispersion of particles during the drying process. The rotation and vibration of the rotating disk 510, in combination with the use of ultrasonic waves, can break the weak attraction between particles, keeping the particles in an independent state at all times and avoiding aggregation. By precisely controlling the temperature and pressure during the drying process, the sublimation rate of ice crystals can be optimized, improving the drying efficiency while ensuring that the physical and chemical properties of the particles are not affected. It is also applicable to various fields with high requirements for particle size and dispersion. By directly removing moisture through the sublimation of ice crystals, the aggregation of particles caused by the surface tension of liquid water is avoided, thus maintaining the original particle size and uniform dispersion of the particles.

[0062] It should be noted that the specific model specifications of the temperature sensor 101, pressure sensor 102, and reduction motor 530 need to be selected according to the actual specifications of the device, etc. The specific selection calculation method uses the existing technology in this field, so it will not be elaborated in detail.

[0063] The power supply and principle of the temperature sensor 101, pressure sensor 102, and reduction motor 530 are clear to those skilled in the art and will not be described in detail here.

[0064] As described above, it is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any person skilled in the art within the technical scope disclosed in this application can easily think of changes or substitutions, which should all be covered within the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

1. A freeze-drying device for the preparation of heavy calcium carbonate, characterized in that, Comprising A drying chamber (100), which is a sealed container for accommodating particulate materials to be dried; A refrigeration system (200), connected to the drying chamber (100), for freezing the particulate materials below the freezing point to form ice crystals in the materials; A vacuum system (300), connected to the drying chamber (100), for creating a vacuum environment in the drying chamber (100) to directly sublimate the ice crystals; A heating system (400), disposed inside or outside the drying chamber (100), for providing the heat required for the sublimation of the ice crystals; A material dispersion mechanism (500), disposed in the drying chamber (100), for keeping the particulate materials in a dispersed state during the drying process.

2. The freeze-drying device for preparing heavy calcium carbonate according to claim 1, wherein, A temperature sensor (101) and a pressure sensor (102) are further provided in the drying chamber (100) for monitoring the temperature and pressure in the drying chamber (100) respectively, so as to control the drying process in real time.

3. A freeze-drying device for preparing heavy calcium carbonate according to claim 1, characterized in that, The refrigeration system (200) includes a compressor, a condenser, an evaporator and a throttling device, and realizes the refrigeration of the drying chamber (100) through the circulating flow of the refrigerant, freezes the particulate materials below the freezing point, and forms ice crystals in the materials.

4. A freeze-drying device for preparing heavy calcium carbonate according to claim 1, characterized in that, The vacuum system (300) includes a vacuum pump (310) and a vacuum pipeline (320). The vacuum pump (310) is connected to the drying chamber (100) through the vacuum pipeline (320) for pumping out the gas in the drying chamber (100) to create a vacuum environment and directly sublimate the ice crystals into water vapor.

5. The freeze-drying device for preparing heavy calcium carbonate according to claim 1, characterized in that, The heating system (400) includes a heating element (410) and a temperature controller (420). The heating element (410) is disposed inside the drying chamber (100), and the temperature controller (420) is used to control the heating power of the heating element (410) to maintain the temperature stability in the drying chamber (100), provide heat for the sublimation of the ice crystals, and maintain the sublimation process.

6. A freeze-drying device for preparing heavy calcium carbonate according to claim 1, characterized in that, The material dispersion mechanism (500) is disposed in the drying chamber (100) and includes a rotating disk (510) and a vibration device (520); the rotating disk (510) is disposed at the bottom of the drying chamber (100), and the vibration device (520) is connected to the rotating disk (510) for causing the rotating disk (510) to vibrate. An ultrasonic generator is disposed at the bottom of the drying chamber (100) for emitting ultrasonic waves to the particulate materials to promote the dispersion of the particles.

7. A preparation method of heavy calcium carbonate, characterized in that, Comprising The freeze-drying device for preparing heavy calcium carbonate according to any one of claims 1-6; and the following steps: S1. Raw material screening: Screening limestone with a calcium oxide content of more than 54% as the production raw material; S2. Raw material crushing: Crushing the screened calcium oxide; S3. Stirring and pulping: Placing the crushed raw materials in a stirring container and stirring with water to make the mixture uniform; S4. Grinding and demagnetization: Wet grinding and wet demagnetization to remove the magnetic substances brought by the equipment wear during the raw materials and crushing process, improve the purity, and reduce the influence of foreign substances on the whiteness of the product; S5. Dehydration treatment: Vacuum freeze-drying is used to dehydrate and dry the material after S4 treatment; S6. Crushing.

8. The preparation method of heavy calcium carbonate according to claim 7, characterized in that, In the process of S2, coarse crushing is carried out first, then fine crushing, and a grinding aid is added to improve the crushing efficiency and reduce energy consumption.

9. The preparation method of heavy calcium carbonate according to claim 8, characterized in that, In S2, the finely crushed raw materials are classified, and the raw materials that do not meet the classification requirements are introduced into S2 for fine crushing treatment.

10. The preparation method of heavy calcium carbonate according to claim 9, characterized in that, A dispersant is added in S3 to prevent agglomeration.

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