Preparation method and forming equipment of light high-strength hollow perforated ceramic ball

Abstract

The invention discloses a preparation method of a light-weight high-strength hollow perforated ceramic ball, which comprises the following steps of: adding water into aluminum oxide serving as a main material and kaolin, silicon dioxide and the like serving as auxiliary materials, mixing, ball-milling to prepare ceramic slurry with better flowability under a certain extrusion force, regulating and controlling the injection pressure to be 10-20MPa, pressing the ceramic slurry in a material storage cavity into an upper cavity and a lower cavity, and forming a hollow ceramic ball with a hollow hole in the upper cavity and a hollow hole in the lower cavity, thereby obtaining the light-weight high-strength hollow perforated ceramic ball. After the surface of the hollow ceramic ball in the cavity is hardened, starting the trepanning cylinder to enable the trepanning core mold in the upper cavity to return, synchronously ejecting a ceramic ball blank moving upwards along with the upper cavity and the injection port to be placed on the blanking plate under the action of the ejector rod, rotating the blanking plate outwards, taking out the ceramic ball and the injection port blank, and forming the hollow ceramic ball in the cavity. Performing low-temperature surface drying and high-temperature sintering air cooling on the ceramic ball blank to normal temperature, and discharging to obtain the hollow perforated ceramic ball; the hollow porcelain ball and the open holes can be manufactured together, the forming method is simpler, the number of the open holes is larger, the axes of the open holes are perpendicular to the tangent line on the spherical surface all the time, and the hollow porcelain ball is low in manufacturing cost.

Description

Technical Field

[0001] The present invention relates to ceramic balls, and more particularly to an alumina hollow ceramic ball with light weight, high strength, high temperature resistance and corrosion resistance. Background Art

[0002] Alumina hollow ceramic balls have the characteristics of lighter weight, higher hardness, corrosion resistance, wear resistance, etc. compared with alumina solid balls. Therefore, they have a wide range of applications in the fields of chemical industry, metallurgy, environmental protection, etc. Alumina hollow ceramic balls are not only a new type of high-temperature heat insulation material, but also in the field of petrochemical industry, hollow ceramic balls can be used as catalyst carriers, reactor fillers, etc.; in the environmental protection field, hollow ceramic balls can be used for waste gas treatment, water treatment, etc. In short, hollow ceramic balls are a new high-tech material with broad application prospects.

[0003] In order to improve the performance of alumina hollow ceramic balls as catalyst carriers in the catalytic cracking unit of petrochemical industry, so that the catalyst can play a better role and improve the reaction efficiency; in the aeration tank of sewage treatment, in order to increase the gas-liquid contact area, improve the aeration effect, and promote the degradation of pollutants in sewage, some people now use perforated hollow alumina ceramic balls. This is because perforated hollow ceramic balls not only have the performance characteristics of hollow ceramic balls, but also have a large specific surface area, and their porosity is 15-20% higher than that of hollow ceramic balls, and the porosity can reach more than 80%, which has a unique role in sewage and waste gas treatment.

[0004] Currently, the main preparation methods of various perforated ceramic balls are as follows: First: Perforated solid ceramic balls ( Figure 1 shown): One is to use die extrusion molding, and the holes are made together during die pressing. The problem is that the axes of the holes are all vertical (that is, Figure 1 the axis of the hole is perpendicular to the horizontal axis of the ceramic ball, simply referred to as "straight hole"), which restricts the flow direction of the fluid around the ceramic ball, and the holes are mainly concentrated on the top surface of the ball (the spherical crown position), with few holes and low porosity; the other is to use granulation molding, and special fixtures are required for machining and drilling, which affects the production efficiency and increases the manufacturing cost. Second: Hollow ceramic balls ( Figure 2One method is to heat porcelain ball raw materials into a liquid state by electric heating and then blow the liquid raw materials with compressed air to make hollow porcelain balls. The main problems of this method are high manufacturing cost, relatively complex operation, and some limitations on the size of the manufactured hollow porcelain balls. The diameter of the hollow porcelain balls is generally below 5-8 mm. At the same time, for the hollow balls made by this method, special fixture machining is required for drilling the holes. Not only is the hole-opening efficiency low, but the number of holes on the hollow porcelain balls is small, and the hollow balls are prone to breakage during hole-opening. Another method is injection molding extrusion. The main problems of this injection molding extrusion method are that a combustible material is first used to make the inner core of the hollow ball, and the inner core needs to be dried and shaped. When the holes are made together during die pressing, the problem is that the hole axes are all vertical (i.e., the hole axes are perpendicular to the horizontal axis of the porcelain ball), which restricts the flow direction of the fluid on both sides of the porcelain ball, and the holes are mainly concentrated on the top surface (the spherical crown part) of the ball, and the number of holes is small. When mechanical drilling or laser drilling is used for hole-opening, special fixtures and laser equipment are required, increasing the production cost of hole-opening. Therefore, it is an urgent problem to be solved at present to propose a preparation method for hollow open-hole porcelain balls with low cost, easy operation, a large number of holes, and the hole axes perpendicular to the tangent of the ball surface, as well as a forming device for realizing this method. Summary of the Invention

[0005] In view of the problems existing in the manufacture of hollow open-hole porcelain balls in the above-mentioned prior art, the present invention proposes a preparation method and a forming device for realizing this method, in which not only the hollow porcelain balls and the holes can be made together, but also the forming method is simpler, the number of holes is more, the diameter of the porcelain balls is larger, and the hole axes are always perpendicular to the tangent on the ball surface.

[0006] The steps of the preparation method for the lightweight and high-strength hollow open-hole porcelain balls of the present invention are as follows: 1. Using alumina as the main raw material and kaolin, silica, etc. as auxiliary raw materials, adjusting the ratio according to the use, adding an appropriate amount of water and mixing and ball-milling to make a ceramic slurry with an alumina content of more than 95%, a viscosity of 2000-3000 mPa·S, and good fluidity under a certain extrusion pressure. 2. Purchasing plastic hollow balls with a diameter meeting the requirements for standby. 3. Assembling the pressing die: A. On each semi-circular upper cavity and lower cavity of the upper die and the lower die, an opening core mold is installed. The opening core molds are distributed in concentric circles, and the opening core molds can synchronously make telescopic movements perpendicular to the tangents at the intersection points of the opening core molds and the cavities under the action of the cylinder pressure. B. An ejector rod capable of ejecting the porcelain ball blank is installed on the upper mold. A blanking plate for placing plastic hollow balls and capable of rotating 180 degrees is symmetrically installed between the upper mold and the lower mold. A gate plate that is movably attached to the bottom surface of the blanking plate and can rotate 180 degrees is installed under the blanking plate. When the gate plate rotates 180 degrees outward, all the plastic hollow balls on the blanking plate will automatically fall onto the perforated core mold in the lower mold cavity. C. After the plastic hollow balls are correspondingly positioned on the perforated mold core in the lower mold cavity, rotate the blanking plate outward, and start the upper mold to close the upper mold and the lower mold cavity. D. After closing the mold, start the press, adjust the controlled injection pressure to 10 - 20 MPa, and press the ceramic slurry in the storage hole into the upper mold cavity and the lower mold cavity. While pressing the ceramic slurry, spray an appropriate amount of curing agent into the ceramic slurry in the storage cavity. After the slurry is pressed in, hold the pressure for 60 - 100 seconds. After the surface of the hollow porcelain balls in the mold cavity hardens, start the perforating cylinder to retract the perforated core mold in the upper mold cavity, then start the closing mold, open the upper mold and the lower mold, then rotate the blanking plate inward to the position below the upper mold at the same time, and then start the upper mold to move upward until the limit rod on the ejector rod plate touches the top plate, so that the ejector rod plate receives a downward reaction force. The ejector rod plate moves downward to drive the ejector rod fixed on the ejector rod plate to move downward. Under the action of the ejector rod, the porcelain ball blank and the injection port that move upward with the upper mold are synchronously ejected and fall onto the blanking plate. Then rotate the blanking plate outward, take out the porcelain balls and the injection port blanks, and then place the plastic hollow balls on the blanking plate for standby. 4. Cut and separate the injection port on the porcelain ball blank, and dry the porcelain ball blank at low temperature: dry at normal temperature for more than 24 hours for surface drying, remove the surface moisture, and prevent sintering and cracking. 5. Segmentally roast: After the surface-dried porcelain balls are put into the kiln, first heat up to 200 - 300 °C to decompose and volatilize the plastic hollow balls to form an internal hollow; then heat up to 500 - 800 °C and keep warm for 1 - 2 hours, and then heat up to 1200 - 1600 °C and sinter for 2 - 4 hours, and then cool to normal temperature in the furnace and take out of the furnace. 6. Remove the residual blocks on the surface of the porcelain balls and polish them smoothly.

[0007] The differences between the preparation method of the present invention and the existing preparation methods are as follows: A. Use plastic hollow balls to replace the inner cores made of combustibles used in the existing injection molding to prepare hollow ceramic balls, eliminating the processes of mixing materials to make the inner cores and drying and shaping the inner cores. The process of forming hollow ceramic balls is simplified, the production cycle is shortened, and the labor cost for making the inner cores is saved. B. When the ceramic slurry is injection-extruded, multiple synchronously moving perforated cores are used to form openings on the mold. This can not only form multiple layers of openings distributed in concentric rings, but also ensure that the axis of the openings on the sphere surface is always perpendicular to the tangent of the intersection point of the perforated core and the cavity (such openings are simply referred to as "cut openings"). This enables the liquid outside the sphere to flow and adsorb in multiple directions, thereby increasing the gas-liquid contact area and improving the aeration effect by 20 - 30%, promoting the degradation of pollutants in the sewage.

[0008] In the present invention, by a method in which a gate plate and a blanking plate that can rotate 180 degrees outward and inward synchronously or successively around a guide post are respectively and oppositely arranged on each guide post between the upper mold and the lower mold, not only can the gate plate and the blanking plate be used for placing and blanking the plastic hollow balls, but also they can be used to carry and turn out the ceramic hollow ball blanks that fall after ejection. One plate has two uses, and the rotation operation can be manual or motorized, simplifying the molding equipment and improving the working efficiency of porcelain ball molding.

[0009] The hollow perforated porcelain balls of the present invention are different from ordinary porcelain balls in the following aspects: 1). Structural characteristics: Ordinary porcelain balls are solid spheres with a dense structure and a smooth or slightly rough surface. While the hollow perforated porcelain balls have many small holes opened in a ring shape on the sphere surface, and the holes are penetrated with the hollow, forming a reticular and porous structure.

[0010] 2). Performance characteristics Specific surface area: Due to the porous and hollow structure, the hollow perforated porcelain balls have a larger specific surface area. For example, the specific surface area of ordinary porcelain balls may be several square meters per gram, while that of the hollow perforated porcelain balls can reach dozens of square meters per gram or even higher, which enables it to provide more reaction sites.

[0011] 3). Porosity: The hollow perforated porcelain balls have a very high porosity, which can reach more than 70% - 80%, facilitating the flow and diffusion of gas and liquid inside them, and making the mass transfer smoother. Compared with straight openings with the same number, distribution, and size of cut openings, the gas-liquid flow velocity can be increased, the flow direction and contact area can be increased, and the aeration effect can be improved by 15 - 20%.

[0012] 4). Mechanical properties: Because the hollow perforated porcelain balls are porous inside, their bulk density is generally smaller than that of ordinary porcelain balls (the density of ordinary porcelain balls is 1.8 - 2.2 g / cm³). The density of the hollow perforated porcelain balls is: 0.6 - 1 g / cm³, the bulk density is between 0.6 - 1.2 g / cm³, the compressive strength is: 50 - 100 Mpa, and the wear-resistant hardness is: Mohs hardness 5 - 7.

[0013] 5). Application scenarios A, Ordinary ceramic balls: Commonly used in packed towers in industries such as chemical engineering and metallurgy, they play a role in supporting and distributing gases or liquids, and can also be used as grinding media. For example, in ore grinding, their high strength and wear resistance are utilized to crush ores.

[0014] B, Hollow perforated ceramic balls: Mainly applied in occasions where efficient mass transfer and heat transfer are required. For example, in the catalytic cracking unit of petrochemical industry, as a catalyst carrier, its porous structure enables the catalyst to function better and improves the reaction efficiency; in the aeration tank of sewage treatment, the perforated ceramic balls can increase the gas-liquid contact area, improve the aeration effect, and promote the degradation of pollutants in the sewage.

[0015] The present invention provides a special molding device for realizing the preparation method of the light-weight, high-strength and hollow perforated ceramic balls described in the present invention: It includes a mold frame and an upper mold and a lower mold that can move up and down relatively within the mold frame. The mold frame includes a wall panel and a base connected by four columns. Two opposite guide columns are connected between the wall panel and the base. The two ends of the upper mold and the lower mold are movably arranged on the guide columns. A push rod plate and push rods are arranged on the upper mold. On each guide column, a gate plate and a blanking plate that can rotate outward and inward around the guide column are respectively arranged opposite to each other. Before mold closing, after the gate plate and the blanking plate synchronously rotate inward between the upper mold and the lower mold, the gate plate first rotates outward in the reverse direction to make the plastic hollow balls placed on the blanking plate freely fall and fill into the lower cavity, and then the blanking plate rotates outward in the reverse direction onto the gate plate and then mold closing is carried out. One end of the upper mold is provided with a storage cavity. The lower end of the storage cavity is communicated with an eight-shaped side injection port arranged on the bottom surface of the upper mold. One end of the side injection port is connected to one end of the inner injection port, and the other end of the inner injection port is connected in series with the upper cavity. An extrusion plate connected to a press is arranged inside the upper end of the storage cavity. A curing agent injection port and a slurry feed port are respectively arranged on both sides of the storage cavity. On each semi-circular upper cavity and lower cavity of the upper mold and the lower mold, a perforating core mold is equipped. The perforating core molds are distributed in concentric circles. Under the action of the extrusion force, the perforating core molds can synchronously make a telescopic movement perpendicular to the tangent of the intersection point of the perforating core mold and the cavity in the mold.

[0016] The present invention has the following characteristics compared with the prior art: 1. On each semi-circular upper cavity and lower cavity of the upper mold and the lower mold, a perforating core mold is equipped. The perforating core molds are distributed in concentric circles on the horizontal plane, and the axis of the perforating core mold is perpendicular to the tangent of the intersection point of the perforating core mold and the cavity. The perforating core molds are synchronously driven by perforating cylinders. Therefore, a number of perforations distributed in concentric circles can be made on the spherical surface, and the axis of the perforation is perpendicular to the spherical tangent and communicates with the spherical cavity. In this way, since the axes of the perforations are uniformly spaced in a ring and intersect with the vertical axis of the sphere, the problem caused by the parallelism between the axis of the perforation of the existing perforated hollow ceramic ball and the vertical line of the sphere, which is prone to form turbulent flow, is solved. Compared with the existing perforated ceramic balls, the porosity of the ceramic balls is increased, and the liquid flow velocity and adsorption effect can also be improved.

[0017] The present invention uses plastic hollow balls to form the inner core of hollow ceramic balls, replacing the use of combustibles in the prior art to produce the inner core of hollow balls, and the inner core needs to be dried and shaped, simplifying the process of forming hollow ceramic balls and saving the preparation man-hour cost (the cost can be reduced by 5-10%); compared with mechanical processing for opening holes, no drilling fixture is required, not only the cost can be reduced by 10%, but also the hole-opening efficiency is high, the number of holes opened on the hollow porcelain balls is large, and the hollow balls will not be damaged during hole-opening.

[0018] The present invention makes full use of the hole-opening core mold to form holes and also uses it to support and fix the plastic hollow balls for forming ceramic hollows, making the inner cavity of the ceramic hollow balls round and the wall thickness uniform, thereby improving the compressive strength and strength uniformity of the ceramic spheres.

[0019] On each guide post between the upper mold and the lower mold of the present invention, a gate plate and a blanking plate are respectively arranged opposite to each other and can rotate 180 degrees outward and inward around the guide post synchronously or successively. It can not only be used to place and blank the plastic hollow balls with the gate plate and the blanking plate, but also be used to carry and turn out the falling ceramic hollow ball blanks after ejection. One plate is used for two purposes, and the rotation operation can be manual or motorized, simplifying the molding equipment and improving the working efficiency of porcelain ball molding. Description of the Drawings

[0020] Figure 1 is a schematic structural diagram of a solid open-hole porcelain ball in the prior art, Figure 2 is a schematic structural diagram of a hollow open-hole porcelain ball in the prior art, Figure 3 is a schematic structural diagram of the hollow open-hole porcelain ball of the present invention, Figure 4 is a main sectional structural diagram of the molding equipment of the hollow open-hole porcelain ball of the present invention, Figure 5 is Figure 4 the enlarged partial sectional structural diagram of X-X in Figure 6 is Figure 4 the sectional structural diagram of A-A in Figure 7 is Figure 6 the sectional structural diagram of B-B in Figure 8 is Figure 6 the sectional structural diagram of C-C in Figure 9 is the schematic plan structure diagram of the blanking plate of the present invention, Figure 10 is Figure 9 the enlarged partial sectional structural diagram of D-D of

[0021] In the figure, 1. upper mold, 2. perforated cylinder, 3. pressing plate, 4. limiting plate, 5. ceramic slurry, 6. guiding hole, 7. perforated core mold, 8. upper cavity, 9. plastic hollow ball, 10. lower cavity, 11. opening, 12. locking nut, 13. guide post, 14. column, 15. avoidance groove, 16. blanking hole, 17. lower mold, 18. base, 19. connecting screw, 20. gate plate, 21. blanking plate, 22. fastening screw, 23. inner injection port, 24. support beam, 25. fixing sleeve, 26. die clamping cylinder, 27. adjusting nut, 28. wall panel, 29. ejector rod, 30. storage cavity, 31. side injection port, 32. convex body, 33. ejector rod plate, 34. limiting rod, 35. hopper, 36. slurry inlet, 37. extrusion plate, 38. pressure cylinder, 39. curing agent injection port, 40. positioning pin, 41. limiting pin, 42. limiting rod, 43. upper swivel sleeve, 44. lower swivel sleeve, 45. ear platform. Detailed implementation mode

[0022] I. The preparation method steps of the lightweight and high-strength hollow perforated porcelain ball of the present invention are as follows: 1. Using alumina as the main material and kaolin, silica, etc. as auxiliary materials, adjusting the ratio according to the use, adding water and mixing and ball milling to make a ceramic slurry with an alumina content of 98%, a viscosity of 2500 - 2600 mPa·S, and having good fluidity under an extrusion pressure of 15 - 16 MPa, and a water content of 20 - 30%. 2. Purchasing plastic hollow balls with an outer diameter of 22 mm for standby. 3. Assembling the pressing mold: A. A perforated core mold is assembled on each semi-circular upper cavity and lower cavity of the upper mold and the lower mold. The perforated core molds are distributed in concentric circles (that is, one opening is provided perpendicular to the central axis, and four openings with their centers located on the first circle are provided on the spherical surface outside the central axis. Six openings with their centers located on the second circle are provided on the surface of the four-opening porcelain ball. The openings on the first circle are staggered from the openings on the second circle. The perforated core mold can synchronously make a telescopic movement perpendicular to the tangent of the intersection point of the perforated core mold and the cavity under the action of the cylinder pressure. The diameter of the upper cavity is 30 mm (that is, the outer diameter of the hollow perforated ceramic is 30 mm, and the wall thickness is 4 mm). B. An ejector rod capable of ejecting the porcelain ball blank is assembled on the upper mold. A blanking plate for placing plastic hollow balls and capable of rotating 180 degrees is symmetrically assembled between the upper mold and the lower mold. A gate plate that is movably attached to the bottom surface of the blanking plate and can rotate 180 degrees is assembled under the blanking plate. When the gate plate rotates 180 degrees outward, all the plastic hollow balls on the blanking plate will automatically fall onto the perforated mold core in the lower cavity. C. After the plastic hollow balls are correspondingly positioned on the perforated mold core in the lower cavity, then rotate the blanking plate outward and start the upper mold to make the upper mold and the lower cavity close the mold. D. After closing the mold, start the press, adjust the control injection pressure to 10 - 20 MPa, and press the ceramic slurry in the storage hole into the upper cavity and the lower cavity. While pressing the ceramic slurry, spray an appropriate amount of curing agent into the ceramic slurry in the storage cavity (for the organic curing agent, p-aminobenzenesulfonic acid is selected, and the addition amount is 0.01% of the weight of the ceramic slurry; for the inorganic curing agent, silicate or alumina is selected). After the slurry is pressed in, keep the pressure for 60 - 100 seconds. After the surface of the hollow porcelain balls in the cavity hardens, start the opening cylinder to retract the opening die core in the upper cavity. Then start the mold closing air cylinder (there is a lack of description here, it may be an incomplete expression). Open the upper mold and the lower mold. Then rotate the blanking plate inward to under the upper mold at the same time. Then start the upper mold to move upward until the limit rod on the ejector plate touches the top plate, so that the ejector plate receives a downward reaction force. The ejector plate moves downward to drive the ejector rod fixed on the ejector plate to move downward. Under the action of the ejector rod, the porcelain ball blank and the injection port that move upward with the upper mold are synchronously ejected and fall on the blanking plate. Then rotate the blanking plate outward, take out the porcelain ball and the injection port blank, and then place the plastic hollow ball on the blanking plate for use; 4. Cut and separate the injection port on the porcelain ball blank, and dry the porcelain ball blank at a low temperature: dry it at room temperature for 24 hours for surface drying to remove surface moisture and prevent sintering cracks; 5. Segmentally roast: After putting the surface-dried porcelain balls into the kiln, first heat up to 240°C to decompose and volatilize the plastic hollow balls, forming an internal hollow; then heat up to 650°C and keep it warm for 1.5 hours, and then heat up to 1420°C and sinter for 3.5 hours, and then cool to room temperature in the furnace and take out of the furnace; 6. Remove the residual blocks on the surface of the porcelain balls and polish them smooth.

[0023] The outer diameter of the hollow and open-hole porcelain balls obtained in the above embodiment is detected to be 29.8 mm (the specification standard is 30 mm), the density is 0.89 g / cm³, the bulk density is between 0.95 g / cm³, the compressive strength is 74.60 Mpa, and the wear-resistant hardness is Mohs hardness 6.7.

[0024] II. The specific implementation manner of the hollow and open-hole porcelain ball forming equipment is as follows: In the figure, it includes a mold base and an upper mold 1 and a lower mold 17 that can move up and down relatively within the mold base. The mold base includes wall plates 28 and a base 18 connected by four columns 14. The upper ends of the columns are connected to the wall plates with lock nuts 12. Two opposite guide columns 13 are connected between the wall plates and the base. On each guide column, a gate plate 21 and a blanking plate 20 that can rotate outward and inward around the guide column are respectively arranged opposite to each other. The lug bosses 45 at both ends of the upper mold and the lower mold are movably arranged on the guide columns. Two positioning pins 40 for mold closing are arranged between the upper mold and the lower mold. The upper ends of the guide columns are connected to the wall plates with lock nuts 12. The lower ends of the columns and the guide columns are both fixedly connected to the base. The lower mold is fixedly connected to the base with connecting screws 19. A support beam 24 distributed in a grid shape is fixedly connected to the top of the upper mold with fastening screws 22. A mold closing cylinder 26 is fixedly arranged in the middle upper part of the wall plate. The lower end of the piston rod of the mold closing cylinder movably passes through the wall plate and is connected to the support beam with a fixed sleeve 25. There is an avoidance groove 15 between the lug bosses when the mold is closed. A ejector plate 33 and ejector rods 29 are arranged on the upper mold. The lower ends of the ejector rods can movably pass through the upper mold. The upper ends of the ejector rods are screws and are connected to the ejector plate 33 with lock nuts 12 and adjusting nuts 27. The ejector plate is provided with a limit rod 34. When the upper mold is opened (i.e., the upper mold moves upward), the ejector plate can rise with the upper mold. When the upper end of the limit rod on the ejector plate rises and touches the wall plate, the ejector plate will move downward and drive the ejector rods to move downward synchronously. Since all the injection ports are on the upper mold, when the mold is opened, the ceramic balls and the injection port blanks will remain on the upper mold, so that all the ceramic balls and the injection port blanks (including the side injection port 31 and the inner injection port 23) that rise with the upper mold can be ejected downward synchronously and placed on the blanking plate 21. Semi-circular upper cavities 8 and lower cavities 10 arranged in a matrix are provided in both the upper mold and the lower mold (in this embodiment, both the upper cavity and the lower cavity are three rows and six columns). In the middle and beside each upper cavity in the upper mold, an open-hole core mold 7 is arranged. Except for the open-hole core molds in the middle, the other open-hole core molds are distributed in two circular ring layers on the upper hemisphere surface (in this embodiment, the diameter of the ceramic ball is 30 mm, and it can also be 40 or 50 mm). There are 4 openings 11 on the first ring (when the outer diameter of the hollow open-hole porcelain ball is 30 mm, the aperture of the opening is 4 mm; when the outer diameter of the hollow open-hole porcelain ball is 50 mm, the aperture of the opening is 6 mm. The specific number, distribution, and size of the openings are determined according to the size of the hollow open-hole porcelain ball). There are 6 openings on the second ring. The openings on the two rings are arranged staggeredly. Similarly, there are also two layers of ring-layer distributions on the lower hemisphere surface of the open-hole core mold. The diameter of the open-hole core mold is the aperture of the opening. One end of each open-hole mold core is fixedly connected to a limit plate 4 at one end of the piston rod. The limit plate can move in the guide hole 6 under the action of the opening cylinder 2 on the piston rod and the pressing plate 3. One piston rod is equipped with one opening cylinder, or the piston rods of the same ring can be assembled into one body and equipped with one opening cylinder. The pressing plate 3 is fixed on the upper mold and the lower mold. All the opening cylinders are connected to the same air source. After the upper mold starts to rise,All the hole-opening cylinders work synchronously under the pressure of the same air source, so that the hole-opening core mold moves synchronously, and the axis of the hole-opening core mold is perpendicular to the tangent of the intersection point of the hole-opening core mold and the cavity. One end of the blanking plate 21 is connected to the upper rotating sleeve 43 movably arranged on the guide column. The blanking plate is provided with blanking holes 16 whose number and distribution correspond to the number and distribution of the upper (lower) cavity. The aperture of the blanking hole is larger than the diameter of the plastic hollow ball 9 and smaller than the outer diameter of the hollow hole-opening porcelain ball. One end of the gate plate 20 is connected to the lower rotating sleeve 44 movably arranged on the guide column. The upper surface of the gate plate contacts the lower bottom surface of the blanking plate but can rotate staggered with each other. Before the mold is formed, the total height of the upper rotating sleeve and the lower rotating sleeve is less than the height of the avoidance groove to ensure that the upper mold and the lower mold can be molded after the blanking plate and the gate plate are rotated outward. In order to ensure that the blanking plate and the gate plate can rotate 180 degrees, two limit pins 41 (in the diameter direction) are arranged on the upper rotating sleeve and the lower rotating sleeve relative to each other, and a limit rod 42 that can contact the limit pin is arranged on one side of the lower mold, that is, when the blanking plate and (or) the gate plate are rotated counterclockwise until the limit pin contacts the limit rod, the blanking plate and (or) the gate plate are rotated 180 degrees and enter the conveyor belt and output the ceramic hollow balls and injection port blanks thereon. At the same time, the plastic hollow ball can be discharged at the blanking position. After the gate and the blanking plate are synchronously rotated inward between the upper mold and the lower mold, the gate is first rotated outward in the opposite direction to allow the plastic hollow ball placed on the blanking plate to fall freely and fill into the lower cavity. After the blanking plate is reversed and rotated outward on the gate plate, the mold is closed. A storage cavity 30 is provided at one end of the upper mold. A fixed amount of ceramic slurry 5 is stored in the storage cavity. The lower end of the storage cavity is communicated with a side injection port 31 in an eight-shaped shape arranged on the bottom surface of the upper mold. The side injection port is connected to one end of the inner injection port 23, and the other end of the inner injection port is connected in series with the upper cavity. , Since the side injection port and the inner injection port are both located on the upper mold, after the upper mold and the lower mold are opened, the ceramic hollow ball and the injection port blank will remain on the upper mold, and then the ceramic hollow ball and the injection port blank will be ejected by the ejector and placed on the blanking plate for output. An extrusion plate 37 connected with a pressure cylinder 38 (oil cylinder or air cylinder) is provided in the upper end of the storage cavity. The upper molds on both sides of the storage cavity are respectively provided with a curing agent injection port 39 and a slurry feed port 36. The slurry feed port is connected to a hopper 35. The height of the inner injection port is generally 3-5 mm, and the height of the side injection port is 5-10 mm. In order to increase the strength of the two ejector rods located outside the side injection port in the upper mold, a circular convex body 32 is provided on the two ejector rods. ,

Claims

1. A preparation method of a lightweight and high-strength hollow and perforated porcelain ball, characterized in that: The steps of the preparation method are as follows: 1) Using alumina as the main material and kaolin, silica, etc. as auxiliary materials, adjusting the ratio according to the usage, adding an appropriate amount of water and mixing and ball-milling to make a ceramic slurry with an alumina content of more than 95%, a viscosity of 2000 - 3000 mPa·S, and having good fluidity under a certain extrusion pressure. 2) Purchasing plastic hollow balls with a diameter meeting the regulations for standby. 3) Assembling the compression mold: A. On each semi-circular upper cavity and lower cavity of the upper mold and the lower mold, there is an open-hole core mold installed. The open-hole core molds are distributed in concentric circles and can synchronously make a telescopic movement perpendicular to the tangent of the intersection point of the open-hole core mold and the cavity in the mold under the action of the cylinder pressure. B. On the upper mold, there is a ejector rod that can eject the porcelain ball blank. Between the upper mold and the lower mold, there is a blanking plate symmetrically installed for placing plastic hollow balls and capable of rotating 180 degrees. Under the blanking plate, there is a gate plate that is movably attached to the bottom surface of the blanking plate and can rotate 180 degrees. When the gate plate rotates 180 degrees outward, all the plastic hollow balls on the blanking plate will automatically fall onto the open-hole mold core in the lower cavity. C. After the plastic hollow balls are correspondingly positioned on the open-hole mold core in the lower cavity, then rotate the blanking plate outward and start the upper mold to make the upper mold and the lower cavity close the mold. D. After closing the mold, start the press, adjust the control injection pressure to 10 - 20 MPa, and press the ceramic slurry in the storage hole into the upper cavity and the lower cavity. While pressing the ceramic slurry, spray an appropriate amount of curing agent into the ceramic slurry in the storage cavity. After the slurry is pressed in, keep the pressure for 60 - 100 seconds. After the surface of the hollow porcelain ball in the cavity hardens, then start the open-hole cylinder to retract the open-hole mold core in the upper cavity. Then start the closing cylinder (lack of description in the original text, assuming it's a misspelling and should be closing cylinder), open the upper mold and the lower mold, then simultaneously rotate the blanking plate inward to under the upper mold, and then start the upper mold to move upward until the limit rod on the ejector rod plate touches the top plate, so that the ejector rod plate receives a downward reaction force. The ejector rod plate moves downward, driving the ejector rod fixed on the ejector rod plate to move downward. Under the action of the ejector rod, the porcelain ball and the injection port blank that move upward with the upper mold are synchronously ejected onto the blanking plate. Then rotate the blanking plate outward, take out the porcelain ball and the injection port blank, and then place the plastic hollow balls on the blanking plate for standby. 4) Cut and separate the injection port on the porcelain ball blank, and dry the porcelain ball blank at a low temperature: dry at room temperature for more than 24 hours for surface drying to remove surface moisture and prevent sintering cracks. 5) Segmentally bake: After putting the surface-dried hollow porcelain balls into the kiln, first heat up to 200 - 300 °C to decompose and volatilize the plastic hollow balls to form an internal hollow. Then heat up to 500 - 800 °C and keep warm for 1 - 2 hours, and then heat up to 1200 - 1600 °C and sinter for 2 - 4 hours, and then cool to room temperature in the furnace with the furnace to obtain hollow open-hole porcelain balls. 6) Remove the residual blocks on the surface of the hollow open-hole porcelain balls and polish them smoothly.

2. A forming device for preparing the lightweight and high-strength hollow and perforated porcelain balls described in claim 1, characterized in that: It comprises a mold frame and an upper mold (1) and a lower mold (17) which can be lifted up and down relatively in the mold frame. The mold frame comprises a wall panel (28) and a base (18) connected by four uprights (14). Two guide columns (13) are connected between the wall panel and the base. The ends of the upper mold and the lower mold are movably arranged on the guide columns. Each guide column is provided with a gate plate (20) and a blanking plate (21) which can rotate outward and inward around the guide column. The upper mold is provided with a push rod plate (33) and a push rod (29). Each guide column is provided with a gate plate (20) and a blanking plate (21) which can rotate outward and inward around the guide column. Before closing the mold, the gate plate and the blanking plate are synchronously rotated inward between the upper mold and the lower mold. The gate plate is first rotated outward in the opposite direction to allow the plastic hollow ball (9) placed on the blanking plate to freely rotate. After the material is dropped and filled into the lower mold cavity (10), the blanking plate is rotated outwardly in the opposite direction onto the gate plate before the mold is closed. A storage cavity (30) is provided at one end of the upper mold. The lower end of the storage cavity is communicated with an eight-shaped side injection port (31) provided on the bottom surface of the upper mold. The side injection port is connected to one end of the inner injection port (23). The other end of the inner injection port is connected in series with the upper mold cavity. An extrusion plate (37) connected to a press (38) is provided at the upper end of the storage cavity. A curing agent injection port (39) and a slurry feed port (36) are provided on both sides of the storage cavity. A hole opening core mold (7) is installed on each semicircular upper mold cavity (8) and lower mold cavity (10) of the upper mold and the lower mold. The hole opening core molds are distributed in concentric circles. Under the action of the extrusion force, the hole opening core molds can synchronously perform telescopic movement in the mold perpendicular to the tangent line of the intersection point of the hole opening core mold and the mold cavity.

3. The forming device for preparing the lightweight and high-strength hollow and perforated porcelain balls according to claim 2, characterized in that: One end of the blanking plate (21) is connected to an upper rotating sleeve (43) movably arranged on the guide column. The blanking plate is provided with blanking holes (16) whose number and distribution correspond to the number and distribution of the upper (lower) cavities. The diameter of the blanking holes is larger than the diameter of the hollow plastic ball (9) and smaller than the outer diameter of the hollow open-hole ceramic ball. One end of the gate plate (20) is connected to a lower rotating sleeve (44) movably arranged on the guide column. The upper surface of the gate plate contacts the lower bottom surface of the blanking plate but can rotate in a staggered manner. Two limit pins (41) are arranged on the upper rotating sleeve and the lower rotating sleeve in opposition to each other. A limit rod (42) capable of contacting the limit pins is arranged on one side of the lower mold.

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