Ceramic slurry grinding production device

Abstract

The application belongs to the technical field of ceramic slurry and specifically relates to a ceramic slurry grinding production device, which comprises a grinding container and a stirring mechanism. At least one inclined upward extending flow guide groove is arranged on the inner wall of the grinding container. A discharge pipe is arranged on the grinding container. The discharge pipe is communicated with the top of the flow guide groove and is provided with a screen. The ceramic powder is continuously stirred and sheared by the stirring mechanism and grinding balls in the grinding container to obtain qualified slurry. For the qualified slurry, even if the powder and liquid have the same proportion, better flowability and rheology can be displayed due to the reasonable particle size distribution and the in-place coating of dispersing agents. Higher circulation speed can be obtained in the grinding process, so that the slurry can reach a higher height along the groove channel. Qualified slurry flows out first, and the remaining material continues to be ground, thereby improving the grinding efficiency. During the period of qualified slurry flowing out, new material is timely added to realize continuous operation.

Description

Technical Field

[0001] This invention belongs to the field of ceramic slurry technology, and specifically relates to a ceramic slurry grinding production device. Background Technology

[0002] Silicon nitride ceramic powder is a high-hardness powder with characteristics such as low bulk density, large specific surface area, and difficulty in wetting. Therefore, the grinding and production of high-solids-content silicon nitride slurries is quite challenging. To meet the requirements of high-precision ceramic molding based on high-solids-content ceramic slurries, such as 3D printing, tape casting of ultra-thin ceramic plates, and special ceramic coatings, the problem of how to efficiently grind high-solids-content silicon nitride slurries is crucial. Specifically, photopolymerization printing equipment requires the ceramic slurry to have sufficient viscosity and flowability for self-leveling and reflow effects, while the ceramic sintering process requires a sufficiently high volume fraction of ceramic particles in the ceramic slurry used for photopolymerization printing. Furthermore, effective grinding of the slurry requires thorough and efficient integration of the liquid resin and the ceramic powder, with the powder particles in a low-energy state within the resin, preventing flocculation and agglomeration.

[0003] Existing ceramic slurry production equipment has a high rate of disordered collisions between ceramic particles and with the agitator. Furthermore, both qualified and unqualified ceramic particles are always present in the system, causing excessive energy to be converted into heat. This results in low grinding efficiency and long cycles. Moreover, existing equipment can only produce one batch of slurry before the next batch can be produced, making continuous operation impossible and resulting in low production efficiency. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a ceramic slurry grinding production device with high grinding efficiency and continuous operation.

[0005] This invention provides a ceramic slurry grinding production apparatus, comprising:

[0006] A grinding container, wherein at least one upwardly extending guide groove is formed on the inner wall of the grinding container, a discharge pipe is provided on the grinding container, the discharge pipe is connected to the top of the guide groove and a screen is provided thereon, and a feed inlet is provided on the grinding container; and

[0007] A stirring mechanism is used to stir the ceramic slurry to rotate and flow within the grinding container.

[0008] Optionally, the inclination angle of the flow guide groove is 20°~55°.

[0009] Optionally, the width of the flow guide groove does not exceed 0.8 times the diameter of the grinding ball.

[0010] Optionally, the feed inlet includes a solid feed inlet and a liquid feed inlet, which are respectively located at the top and bottom of the grinding container.

[0011] Optionally, the solid feed inlet is located near the axis of the grinding container, and the solid feed inlet is connected to a feed guide.

[0012] Optionally, a baffle is provided on the inner wall of the grinding container to restrict the grinding balls in the area below the baffle.

[0013] Optionally, the baffle plate is in the shape of a ring structure, and the radial width of the baffle plate is 0.15 to 0.45 times the inner diameter of the grinding container, and the baffle plate is located at 0.4 to 0.6 times the inner cavity height of the grinding container.

[0014] Optionally, the inner cavity volume of the grinding container is 0.5L~2L.

[0015] Optionally, the stirring mechanism includes a motor and a stirring paddle connected to the output shaft of the motor.

[0016] Optionally, the stirring paddle includes a main shaft and multiple sets of blades disposed on the main shaft, each set of blades being evenly distributed around the main shaft, and the length of the blades gradually decreasing from the end of the main shaft to near the motor.

[0017] The beneficial effect of this invention is that the ceramic powder is continuously stirred, sheared and ground in the grinding container by the stirring mechanism and grinding balls, gradually producing ceramic powder with qualified particle size, and then forming qualified slurry. For qualified slurry, due to factors such as reasonable particle size distribution and proper coating of dispersant, even if the powder and liquid ratio is the same, it will show better fluidity. The better fluidity will obtain a higher circulation speed during the grinding process, so that these slurries can reach a higher height along the groove channel. At this point, two different effects exist within the slurry being ground: Insufficiently ground and dispersed ceramic powder, due to its significantly larger particle size, will gradually sink under the disturbance effect of stirring, and will be continuously sheared and ground by the stirring paddle and grinding balls, gradually becoming finer and more dispersed. Meanwhile, the slurry rich in appropriately sized and sufficiently dispersed stable particles is more easily affected by the fluid field carrying effect, causing it to rotate and flow faster. Simultaneously, the grinding balls near the guide groove are propelled upwards or downwards along the guide groove by the stirring mechanism and the guide groove itself (depending on whether the guide groove's direction is the same as the stirring direction), enhancing this fluid field carrying effect. This causes the slurry in the guide groove to flow upwards or downwards more quickly, passing through the screen first and continuously flowing out of the discharge pipe. The remaining material continues to be ground, thus improving grinding efficiency. During the outflow of qualified slurry, new material can be added as needed based on the remaining slurry in the grinding container, enabling continuous operation and improving production efficiency. Attached Figure Description

[0018] Figure 1This is a schematic diagram of the ceramic slurry grinding production device of the present invention;

[0019] Figure 2 This is a schematic diagram of the internal structure of the grinding container of the present invention;

[0020] Figure 3 This is a schematic diagram of the stirring mechanism of the present invention.

[0021] In the diagram: 100, grinding container; 110, flow guide groove; 120, discharge pipe; 130, screen; 141, solid feed inlet; 142, liquid feed inlet; 150, baffle plate; 151, assembly groove; 160, feed guide component; 170, liquid feed pipe; 200, stirring mechanism; 210, motor; 220, main shaft; 230, impeller. Detailed Implementation

[0022] like Figure 1-3 As shown, the present invention provides a ceramic slurry grinding production apparatus, comprising: a grinding container 100 and a stirring mechanism 200. The inner wall of the grinding container 100 is provided with at least one obliquely upward extending flow guide groove 110. The grinding container 100 is provided with a discharge pipe 120, which is connected to the top of the flow guide groove 110 and is provided with a screen 130. The grinding container 100 is provided with a feed inlet. The stirring mechanism 200 is used to stir the ceramic slurry to rotate and flow within the grinding container 100.

[0023] Compared with the prior art, the ceramic slurry grinding production device provided by the present invention continuously stirs, shears and grinds ceramic powder in the grinding container 100 by the stirring mechanism 200 and grinding balls, gradually producing ceramic powder of qualified particle size, and then forming qualified slurry. For qualified slurry, due to factors such as reasonable particle size distribution and proper coating of dispersant, even if the powder and liquid ratio is the same, it will show better fluidity. The better fluidity will obtain a higher circulation speed during the grinding process, so that these slurries can reach a higher height along the groove channel. At this point, two different effects exist within the slurry being ground: Insufficiently ground and dispersed ceramic powder, due to its significantly larger particle size, will gradually sink under the disturbance effect of stirring, and will be continuously sheared and ground by the stirring paddle and grinding balls, gradually becoming finer and more dispersed; while the slurry rich in appropriately sized and sufficiently dispersed stable particles is more easily affected by the fluid field carrying effect and rotates and flows faster. Simultaneously, the grinding balls near the guide groove 110 are pushed by the stirring mechanism 200 and guided by the guide groove 110, rolling rapidly upwards or downwards along the guide groove 110 (depending on whether the guiding direction of the guide groove 110 is the same as the stirring direction), strengthening this fluid field carrying effect. This causes the slurry in the guide groove 110 to flow upwards or downwards more quickly, passing through the screen 130 first and entering the discharge pipe 120 for continuous outflow. The remaining material continues to be ground, thus improving grinding efficiency. During the outflow of qualified slurry, new material can be added in a timely manner according to the remaining slurry in the grinding container 100, achieving continuous operation and improving production efficiency.

[0024] It should be noted that, due to its structural characteristics and working principle, this invention is more suitable for grinding silicon nitride slurry. This is because, compared to zirconium oxide and alumina ceramics, silicon nitride powder has a lower bulk density and a higher specific surface area. The powder is more prone to gradual separation under slow and continuous circulation. Insufficiently ground and dispersed powder tends to settle downwards due to agglomeration and large initial particle size. Organic resin, or newly added organic resin, having the lowest density, spontaneously moves upwards. While fully mixing with the gradually settling powder, it is simultaneously sheared and ground by the grinding balls (such as ceramic ball milling tools, using silicon nitride ceramic balls as an example) and gradually moves slowly towards the edge of the grinding container 100 due to centrifugal force. If grinding ceramics such as zirconium oxide and alumina, due to the significant density difference compared to resin, the newly added ceramic powder will quickly settle to the bottom of the grinding container 100 and remain there. It cannot form an effective mixing effect due to the lifting effect caused by the low density of the organic resin, nor can it rise sufficiently due to the guiding effect of the flow-guiding groove 110.

[0025] In one embodiment, the inclination angle of the flow guide groove 110 relative to the inner bottom surface of the grinding container 100 is determined by the following formula: Inclination angle of the flow guide groove 110 ;

[0026] in K 1 is an empirical constant for the material, related to the physical properties of the grinding balls (such as density and particle size distribution). θ 0 represents the structural constant, which is related to the structural parameters of the barrel and the agitator. η and ρ These are the dynamic viscosity (Pa·S) and density (kg / m³) of the slurry, respectively. 3 ), T The fluidity (mm) of the slurry is measured using a cement mortar fluidity tester.

[0027] When grinding high-solids-content silicon nitride slurry, the value of θ should be in the range of 20° to 55°. If the angle is too small, the liquid resin will be lost from the guide groove 110 too early, causing grinding difficulties or even grinding failure. If the angle is too large, the discharge efficiency will be reduced, affecting the production efficiency.

[0028] In one embodiment, the width of the flow guide groove 110 does not exceed 0.8 times the diameter of the grinding ball; preferably, the width of the flow guide groove 110 is 0.6 to 0.8 times the diameter of the smallest size grinding ball, which can effectively prevent the grinding ball from entering the flow guide groove 110 and hinder the slurry from flowing upward or downward along the flow guide groove 110.

[0029] In one embodiment, the feed inlet includes a solid feed inlet 141 and a liquid feed inlet 142, which are respectively located at the top and bottom of the grinding container 100. It is understood that the solid feed inlet 141 is mainly used for adding silicon nitride powder, and the liquid feed inlet 142 is mainly used for injecting a mixture of resin and additives. The newly added resin, powder, grinding aid, and dispersant enter the system through the solid feed inlet 141 and the liquid feed inlet 142, thus enabling this invention to become a continuous desktop production equipment for high-solids-content ceramic slurry.

[0030] Furthermore, the solid feed inlet 141 is located near the axis of the grinding container 100, and a feed guide 160 is connected to the solid feed inlet 141. A liquid feed pipe 170 is connected to the liquid feed inlet 142. It can be understood that the powder is added from the feed guide 160 located near the top axis of the grinding container 100, and the liquid resin is input under pressure from the resin input pipe near the bottom center of the grinding container 100.

[0031] In one embodiment, a baffle plate 150 is provided on the inner wall of the grinding container 100 to restrict the grinding balls in the area below the baffle plate 150. Understandably, when the stirring mechanism 200 is working, the grinding balls rise along the inner wall of the grinding container 100 and are blocked by the baffle plate 150, falling from a height and causing the slurry to move. The slurry encounters the baffle plate 150 and the container wall, forming a backflow from bottom to top, which enhances the shearing and grinding effect of the grinding balls on the powder particles. Simultaneously, due to the upward movement of the fluid, the finely ground slurry will move upward along the guide groove 110 through the baffle plate 150, facilitating the discharge of the finished slurry.

[0032] Furthermore, the baffle plate 150 is annular in shape and detachably connected to the inner wall of the grinding container 100. The radial width of the baffle plate 150 is 0.15 to 0.45 times the inner diameter of the grinding container 100, and the baffle plate 150 is located at 0.4 to 0.6 times the height of the inner cavity of the grinding container 100. The baffle plate 150 has evenly distributed mounting slots 151 to allow the blade 230 to pass smoothly during installation and maintenance.

[0033] In one embodiment, the inner cavity volume of the grinding container 100 is 0.5L~2L. The ceramic slurry grinding production device provided by the present invention is a desktop production equipment. Under the premise that the process parameters such as grinding aids and dispersants are well matched, it can achieve continuous and efficient grinding of various ceramic slurries in a sufficiently small space, such as an effective volume of 1L and a total power consumption of less than 1kW, and can produce qualified slurries on demand, thereby improving slurry production efficiency.

[0034] In one embodiment, the stirring mechanism 200 includes a motor 210 and a stirring paddle connected to the output shaft of the motor 210.

[0035] In one embodiment, the agitator includes a main shaft 220 and multiple sets of blades 230 disposed on the main shaft 220. Each set of blades 230 is evenly distributed around the main shaft 220, and the length of the blades 230 gradually decreases from the end of the main shaft 220 to near the motor 210. Understandably, the multiple blades 230 are divided into multiple layers along the main shaft 220, each layer being a group, and each group having at least three blades 230. The blades 230 near the motor 210 are shorter, the blades 230 near the grinding container 100 are longer, and the middle section is of moderate length. The slurry quality at the middle blades 230 is basically qualified, exhibiting low viscosity, high fluidity, and a small number of grinding balls. At a lower stirring linear velocity, it is easier to form a significant rotating laminar flow. The flow rate decreases further away from the agitator (closer to the wall of the grinding container 100). At this point, only slurry with better fluidity can cause the liquid level to rise significantly due to the vortex effect formed by rotation, until it naturally overflows above the discharge port height, becoming qualified slurry. The blade 230 is preferably cylindrical, but can also be of other shapes.

[0036] In this embodiment, the grinding container 100 is cylindrical in shape.

[0037] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of protection of this application is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of one or more embodiments of this application as described above, which are not provided in detail for the sake of brevity.

[0038] One or more embodiments in this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of this application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments in this application should be included within the protection scope of this application.

Claims

1. A ceramic slurry grinding production apparatus, characterized in that, include: A grinding container (100) has at least one upwardly extending guide groove (110) on its inner wall. A discharge pipe (120) is provided on the grinding container (100), and a screen (130) is provided between the discharge pipe (120) and the top of the guide groove (110). A feed inlet is provided on the grinding container (100), and the inclination angle of the guide groove (110) is 20°~55°. A stirring mechanism (200) is used to stir ceramic slurry to rotate and flow in the grinding container (100). The stirring mechanism (200) includes a stirring paddle, which includes a main shaft (220) and multiple sets of blades (230) disposed on the main shaft (220). Each set of blades (230) is evenly distributed around the main shaft (220), and the length of the blades (230) gradually decreases from the bottom end to the top end of the main shaft (220). A baffle (150) is provided on the inner wall of the grinding container (100) to restrict the grinding ball in the area below the baffle (150). The baffle (150) is in the shape of a ring structure.

2. The ceramic slurry grinding production apparatus according to claim 1, characterized in that, The width of the flow guide groove (110) does not exceed 0.8 times the diameter of the grinding ball.

3. The ceramic slurry grinding production apparatus according to claim 1, characterized in that, The feed inlet includes a solid feed inlet (141) and a liquid feed inlet (142), which are respectively located at the top and bottom of the grinding container (100).

4. The ceramic slurry grinding production apparatus according to claim 3, characterized in that, The solid feed inlet (141) is close to the axis of the grinding container (100), and the solid feed inlet (141) is connected to a feed guide (160).

5. The ceramic slurry grinding production apparatus according to claim 1, characterized in that, The radial width of the baffle (150) is 0.15 to 0.45 times the inner diameter of the grinding container (100), and the baffle (150) is located at 0.4 to 0.6 times the inner height of the grinding container (100).

6. The ceramic slurry grinding production apparatus according to any one of claims 1-5, characterized in that, The inner cavity volume of the grinding container (100) is 0.5L~2L.

7. The ceramic slurry grinding production apparatus according to any one of claims 1-5, characterized in that, The stirring mechanism (200) also includes a motor (210), the output shaft of which is connected to the stirring paddle.

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