Nano calcium carbonate slurry preparation device

Abstract

The utility model relates to the technical field of nano calcium carbonate production, in particular to a nano calcium carbonate slurry preparation device which comprises a carbonization reactor and a calcium hydroxide slurry mixing device, and the calcium hydroxide slurry mixing device comprises a first vertical cylinder and a second vertical cylinder, the upper ends of the first vertical cylinder and the second vertical cylinder are provided with a first exhaust port and a second exhaust port respectively, openings in the lower ends of the first vertical cylinder and the second vertical cylinder are communicated with the two ends of the U-shaped cylinder respectively, the first vertical cylinder is connected with an air outlet of a first air blower through a first air inlet pipe, and the second vertical cylinder is connected with an air outlet of a second air blower through a second air inlet pipe. A feeding port is formed in the first vertical cylinder, at least one net body is fixed to the inner wall of the U-shaped cylinder, and a liquid discharging port is formed in the lower end face of the U-shaped cylinder. According to the utility model, unreacted calcium oxide particles in calcium hydroxide slurry can be fully crushed, the cost is low, and the purity and the quality of a nano calcium carbonate product are improved.

Description

Technical Field

[0001] This utility model relates to the field of nano-calcium carbonate production technology, specifically to a nano-calcium carbonate slurry preparation device. Background Technology

[0002] Nano-calcium carbonate, as a novel material with unique properties, refers to calcium carbonate particles or powder with a particle size ranging from 1 to 100 nanometers. It is also known in the industry as ultrafine calcium carbonate. When calcium carbonate particles reach the nanoscale, their crystal structure and surface electronic structure undergo significant changes, resulting in quantum size effects, small size effects, surface effects, and macroscopic quantum effects that are not present in ordinary calcium carbonate.

[0003] Quantum size effects endow nano-calcium carbonate with distinctly different optical and electrical properties compared to ordinary calcium carbonate. For example, in optics, nano-calcium carbonate alters the absorption and scattering characteristics of light, allowing it to be used to prepare materials with special optical properties. The small size effect endows nano-calcium carbonate with a larger specific surface area and higher surface energy, resulting in greater reactivity in chemical reactions. Surface effects give nano-calcium carbonate unsaturated surface atoms, enabling strong interactions with other substances and thus improving material properties. Macroscopic quantum effects are manifested in certain special physical phenomena, opening up possibilities for the application of nano-calcium carbonate in high-tech fields.

[0004] Nano-calcium carbonate plays a crucial role in numerous industries due to these unique effects. In the plastics industry, it enhances the strength, toughness, and heat resistance of plastic products, making them more durable. For example, adding nano-calcium carbonate to automotive interior plastic parts improves their impact resistance and dimensional stability. In the rubber industry, nano-calcium carbonate, as a reinforcing agent, significantly improves the abrasion resistance, tear resistance, and tensile strength of rubber, extending the service life of rubber products such as tires and rubber seals. In the paper industry, nano-calcium carbonate can be used as a filler and coating pigment to improve the gloss, opacity, and printability of paper, making it smoother and finer, and improving print quality. In the coatings industry, it increases the hiding power, weather resistance, and abrasion resistance of coatings, while improving their rheological and thixotropic properties, making them easier to apply and spread evenly. In the ink industry, nano-calcium carbonate improves the dispersibility, gloss, and drying speed of inks, resulting in more vibrant and clear colors in printed materials. In the sealant industry, nano-calcium carbonate enhances the bonding strength and sealing performance of sealants, allowing them to better perform their sealing function. In the pharmaceutical industry, nano-calcium carbonate, due to its excellent biocompatibility and safety, can be used as a drug carrier to improve drug stability and bioavailability. In the food industry, nano-calcium carbonate can be used as a calcium fortifier to supplement calcium in food, while also improving the taste and texture of the food.

[0005] Carbonation is currently the core process for producing nano-calcium carbonate, involving several key steps. First, limestone is calcined at high temperatures, decomposing into CaO and CO2. This step requires precise control of the calcination temperature and time to ensure complete decomposition of the limestone while avoiding impurities. Generally, the calcination temperature is between 900 and 1200℃, and the time depends on the particle size and quality of the limestone. Next, the calcined CaO is added to water for a digestion reaction, generating a Ca(OH)2 slurry. Then, the generated Ca(OH)2 slurry undergoes a carbonation reaction with CO2 gas. During this process, appropriate crystal form control agents are added to control the crystal form of the calcium carbonate. Different crystal forms affect the performance and applications of nano-calcium carbonate; for example, cubic nano-calcium carbonate exhibits better reinforcing properties, while needle-like nano-calcium carbonate performs well in thickening and thixotropy. The type and amount of crystal form control agents need to be precisely adjusted according to specific production requirements and product performance.

[0006] After the carbonation reaction is complete, the desired nano-calcium carbonate slurry is obtained. Next, the slurry needs to be dehydrated to remove the water. The dehydrated calcium carbonate then needs to be dried to further reduce the moisture content.

[0007] In the entire carbonation process for producing nano-calcium carbonate slurry, the step of hydrating CaO to generate Ca(OH)₂ slurry is particularly crucial. Because the calcium oxide powder is not uniformly crushed after limestone calcination, unreacted calcium oxide particles are generated in the calcium hydroxide slurry after the calcium oxide powder reacts with water. These unreacted calcium oxide particles will react with carbon dioxide in subsequent carbonation reactions, but due to their different reactivity and reaction rate compared to calcium hydroxide, they will affect the uniformity of the reaction and the purity of the product. For example, unreacted calcium oxide may react rapidly with carbon dioxide in localized areas, forming larger calcium carbonate particles, thus affecting the particle size distribution and purity of nano-calcium carbonate.

[0008] To address the issue of unreacted calcium oxide particles in the raw calcium hydroxide slurry used in the preparation of nano-calcium carbonate slurry, existing technologies generally employ stirring or grinding to break up these particles before the slurry enters the carbonation reactor. However, these methods have significant technical drawbacks:

[0009] (1) For the stirring method, the dispersion of particles in calcium hydroxide slurry is poor, and they are prone to deposit at the bottom of the stirred tank under the action of gravity. The stirring blades of the stirred tank usually cannot reach the bottom, so the particles at the bottom cannot be fully stirred and broken, thus affecting the stirring and breaking effect. Even if the stirring intensity and time are increased, it is difficult to completely solve the problem of particle deposition at the bottom, and excessive stirring may also cause calcium hydroxide particles to agglomerate, further affecting the product quality.

[0010] (2) Although grinding methods can break down particulate matter to a certain extent, they also have many problems. Grinding equipment is expensive, including the cost of equipment purchase, maintenance, and energy consumption. At the same time, the grinding speed is slow, and it takes a long time to break the particulate matter to a suitable particle size, which affects the continuity and efficiency of production. In large-scale production, the processing capacity of grinding equipment is limited and it is difficult to meet production needs, thus limiting the yield and quality of nano-calcium carbonate. Utility Model Content

[0011] To address the technical problem of unreacted calcium oxide particles in calcium hydroxide slurry affecting the purity and quality of nano-calcium carbonate, this invention provides a nano-calcium carbonate slurry preparation device that can fully crush unreacted calcium oxide particles in calcium hydroxide slurry, and is low in cost, thereby improving the purity and quality of nano-calcium carbonate products.

[0012] The present invention adopts the following technical solution:

[0013] A nano-calcium carbonate slurry preparation device includes a carbonation reactor with a calcium hydroxide slurry inlet on the outer shell of the carbonation reactor. It also includes a calcium hydroxide slurry mixing device, comprising a first vertical cylinder and a second vertical cylinder, closed at the top and open at the bottom. The upper ends of the first and second vertical cylinders are respectively provided with a first exhaust port and a second exhaust port. The lower openings of the first and second vertical cylinders are respectively connected to both ends of a U-shaped cylinder. The first vertical cylinder is connected to the outlet of a first blower via a first air inlet pipe, and the second vertical cylinder is connected to the outlet of a second blower via a second air inlet pipe. The first vertical cylinder has a feed inlet. At least one mesh is fixed on the inner wall of the U-shaped cylinder. The lower end face of the U-shaped cylinder has a drain port, which is connected to the calcium hydroxide slurry inlet via a drain pipe.

[0014] It should be further explained that the upper end of the first vertical cylinder is provided with a first sealing cover, and the first exhaust port is provided on the first sealing cover; the upper end of the second vertical cylinder is provided with a second sealing cover, and the second exhaust port is provided on the second sealing cover.

[0015] It should be further noted that the first exhaust port is equipped with a first valve, and the second exhaust port is equipped with a second valve.

[0016] It should be further noted that both the first and second valves are solenoid valves. They are used to add calcium hydroxide slurry into the device.

[0017] It should be further noted that the system also includes a controller, which is electrically connected to the first valve, the second valve, the first blower, and the second blower.

[0018] It should be further explained that the lower opening of the first vertical cylinder is connected to one end of the U-shaped cylinder via a first flange, and the lower opening of the second vertical cylinder is connected to the other end of the U-shaped cylinder via a second flange. Flange connections offer advantages such as tight connections, good sealing performance, and ease of disassembly and installation, facilitating the maintenance and repair of the device.

[0019] It should be further noted that a slurry pump is installed on the drain pipe.

[0020] It should be further noted that the mesh unit is square, and the mesh unit size is 1~5cm.

[0021] The functions of each component in this utility model are as follows:

[0022] The first and second vertical cylinders are closed at the top and open at the bottom. This structural design helps to create a relatively enclosed space, facilitating the control of internal gas and liquid flow. The first vertical cylinder has a first exhaust port at its top, and the second vertical cylinder has a second exhaust port at its top, used to expel gas from the cylinders and ensure normal air blowing within them. The first exhaust port is located on a first sealing cover, and the second exhaust port is located on a second sealing cover; these two sealing covers function to seal the upper ends of the vertical cylinders. A first valve is installed on the first exhaust port, and a second valve is installed on the second exhaust port; both valves are solenoid valves. The solenoid valves can be precisely controlled to open and close via electrical signals, facilitating automated operation.

[0023] Blowers: The first vertical cylinder is connected to the air outlet of the first blower via the first air inlet pipe, and the second vertical cylinder is connected to the air outlet of the second blower via the second air inlet pipe. The function of the blowers is to blow air into the vertical cylinders. By alternately controlling the two blowers, the air pressure causes the calcium hydroxide slurry to flow alternately towards the two vertical cylinders within the device, thereby achieving the purpose of mixing the particles in the slurry with the mesh.

[0024] Drainage port: The drainage port is connected to the calcium hydroxide slurry inlet on the outer shell of the carbonization reactor via a drainage pipe. A slurry pump is installed on the drainage pipe. The function of the slurry pump is to provide power to transport the mixed calcium hydroxide slurry from the U-shaped cylinder into the carbonization reactor.

[0025] This invention also includes a controller, which is electrically connected to the first valve, the second valve, the first blower, and the second blower. The controller can precisely control the opening and closing of the valves and the operating status of the blowers according to preset programs and parameters, thereby achieving automated control of the entire calcium hydroxide slurry mixing process and improving the operating efficiency and stability of the device.

[0026] The beneficial effects of this utility model are as follows:

[0027] This invention features a feed inlet on the first vertical cylinder. The openings at the lower ends of the first and second vertical cylinders are connected to both ends of a U-shaped cylinder, forming a continuous liquid reciprocating flow channel. The prepared calcium hydroxide slurry enters the U-shaped cylinder through the feed inlet. The first blower is started, and the second exhaust port is opened. At this time, the second blower and the first exhaust port are closed. Under the air pressure of the first blower, the slurry in the U-shaped cylinder moves to the right, impacting the mesh as it moves. The mesh acts to block, divide, and disperse the flowing calcium hydroxide slurry, breaking down some large calcium oxide particles to continue reacting with water. When the slurry reaches the highest point of the second vertical cylinder, the second blower is started, the first exhaust port is opened, and the first blower and the second exhaust port are closed. Under the action of air pressure, the slurry in the U-shaped cylinder moves to the left, impacting the mesh as it moves, further mixing the slurry. This process is repeated until a uniformly mixed slurry is obtained after multiple impacts. The slurry is then discharged into the carbonization reactor through the drain port to participate in the reaction. This invention can fully crush unreacted calcium oxide particles in calcium hydroxide slurry at a low cost, thereby improving the purity and quality of nano-calcium carbonate products. Attached Figure Description

[0028] To more clearly illustrate the technical solution of this utility model, the drawings used in the description will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the specific embodiment of this utility model.

[0030] Figure 2 This is a schematic diagram of the mesh structure of a specific embodiment of this utility model.

[0031] In the diagram, 1-first blower, 2-first vertical cylinder, 3-first exhaust port, 4-first sealing cover, 5-feed inlet, 6-first flange, 7-U-shaped cylinder, 8-drain outlet, 9-net body, 10-slurry pump, 11-second flange, 12-first air inlet pipe, 13-second vertical cylinder, 14-second exhaust port, 15-second sealing cover, 16-second blower, 17-drain pipe, 18-carbonization reactor, 19-second air inlet pipe. Detailed Implementation

[0032] To make the objectives, features, and advantages of this utility model more apparent and understandable, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings of the specific embodiments. Obviously, the embodiments described below are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this patent, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this patent.

[0033] Example 1

[0034] Combination Figure 1 This invention provides a device for preparing nano-calcium carbonate slurry, including a carbonation reactor 18, the outer shell of which is provided with a calcium hydroxide slurry inlet.

[0035] This utility model also includes a calcium hydroxide slurry mixing device, which includes a first vertical cylinder 2 and a second vertical cylinder 13, which are closed at the top and open at the bottom. The upper ends of the first vertical cylinder 2 and the second vertical cylinder 13 are respectively provided with a first exhaust port 3 and a second exhaust port 14. The openings at the lower ends of the first vertical cylinder 2 and the second vertical cylinder 13 are respectively connected to the two ends of the U-shaped cylinder 7. The first vertical cylinder 2 is connected to the air outlet of the first blower 1 through the first air inlet pipe 12. The second vertical cylinder 13 is connected to the air outlet of the second blower 16 through the second air inlet pipe 19. The first vertical cylinder 2 is provided with a feed inlet 5. Three mesh bodies 9 are fixed on the inner wall of the U-shaped cylinder 7. The lower end face of the U-shaped cylinder 7 is provided with a drain port 8. The drain port 8 is connected to the calcium hydroxide slurry inlet through a drain pipe 17. A slurry pump 10 is provided on the drain pipe 17.

[0036] The working process of this utility model is as follows:

[0037] The prepared calcium hydroxide slurry enters the U-shaped cylinder 7 through the feed port 5. The first blower 1 is started and the second exhaust port 14 is opened. At this time, the second blower 16 and the first exhaust port 3 are closed. Under the air pressure of the first blower 1, the slurry in the U-shaped cylinder 7 moves to the right and hits the mesh 9. The mesh 9 blocks, divides and disperses the flowing calcium hydroxide slurry, breaking down some large calcium oxide particles to continue reacting with water. When the slurry reaches the highest point of the second vertical cylinder 13, the second blower 16 is started and the first exhaust port 3 is opened. The first blower 1 and the second exhaust port 14 are closed. Under the action of air pressure, the slurry in the U-shaped cylinder 7 moves to the left and hits the mesh 9 again, mixing the slurry. The above operation is repeated. After multiple impacts, a uniformly mixed slurry is obtained and discharged into the carbonization reactor 18 through the drain port 8 to participate in the reaction.

[0038] In some specific embodiments, the upper end of the first vertical cylinder 2 is provided with a first sealing cover 4, and the first exhaust port 3 is provided on the first sealing cover 4. The upper end of the second vertical cylinder 13 is provided with a second sealing cover 15, and the second exhaust port 14 is provided on the second sealing cover 15. This facilitates installation and maintenance.

[0039] In some specific embodiments, a first valve is provided on the first exhaust port 3, and a second valve is provided on the second exhaust port 14. Both the first and second valves are solenoid valves. This utility model also includes a controller, which is electrically connected to the first valve, the second valve, the first blower 1, and the second blower 16. The controller can precisely control the opening and closing of the valves and the working state of the blowers according to preset programs and parameters, thereby realizing automated control of the entire calcium hydroxide slurry mixing process and improving the operating efficiency and stability of the device.

[0040] In some specific embodiments, the lower opening of the first vertical cylinder 2 is connected to one end opening of the U-shaped cylinder 7 via a first flange 6, and the lower opening of the second vertical cylinder 13 is connected to the other end opening of the U-shaped cylinder 7 via a second flange 11. Flange connections offer advantages such as tight connection, good sealing performance, and ease of disassembly and installation, facilitating the maintenance and repair of the device.

[0041] In some specific embodiments, the mesh unit 9 is square, with a mesh unit size of 1~5cm. This is suitable for breaking particles of different sizes while allowing the slurry to pass smoothly through the mesh.

[0042] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A device for preparing nano-calcium carbonate slurry, comprising a carbonation reactor, wherein a calcium hydroxide slurry inlet is provided on the outer shell of the carbonation reactor, characterized in that, It also includes a calcium hydroxide slurry mixing device, which includes a first vertical cylinder and a second vertical cylinder that are closed at the top and open at the bottom. The upper ends of the first vertical cylinder and the second vertical cylinder are respectively provided with a first exhaust port and a second exhaust port. The openings at the lower ends of the first vertical cylinder and the second vertical cylinder are respectively connected to the two ends of a U-shaped cylinder. The first vertical cylinder is connected to the air outlet of a first blower through a first air inlet pipe, and the second vertical cylinder is connected to the air outlet of a second blower through a second air inlet pipe. The first vertical cylinder is provided with a feed inlet. At least one mesh is fixed on the inner wall of the U-shaped cylinder. The lower end face of the U-shaped cylinder is provided with a drain port, and the drain port is connected to the calcium hydroxide slurry inlet through a drain pipe.

2. The nano-calcium carbonate slurry preparation apparatus as described in claim 1, characterized in that, The upper end of the first vertical cylinder is provided with a first sealing cover, and the first exhaust port is provided on the first sealing cover. The upper end of the second vertical cylinder is provided with a second sealing cover, and the second exhaust port is provided on the second sealing cover.

3. The nano-calcium carbonate slurry preparation apparatus as described in claim 2, characterized in that, The first exhaust port is equipped with a first valve, and the second exhaust port is equipped with a second valve.

4. The nano-calcium carbonate slurry preparation apparatus as described in claim 3, characterized in that, Both the first and second valves are solenoid valves.

5. The nano-calcium carbonate slurry preparation apparatus as described in claim 4, characterized in that, It also includes a controller, which is electrically connected to the first valve, the second valve, the first blower, and the second blower.

6. The nano-calcium carbonate slurry preparation apparatus as described in claim 1, characterized in that, The lower opening of the first vertical cylinder is connected to the opening at one end of the U-shaped cylinder via the first flange, and the lower opening of the second vertical cylinder is connected to the opening at the other end of the U-shaped cylinder via the second flange.

7. The nano-calcium carbonate slurry preparation apparatus as described in claim 1, characterized in that, A slurry pump is installed on the drain pipe.

8. The nano-calcium carbonate slurry preparation apparatus as described in claim 1, characterized in that, The mesh unit is square, and the mesh unit size is 1~5cm.

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