A method for reducing the amount of binder pitch used in isostatically pressed graphite products

Abstract

The present application relates to a kind of methods for reducing the amount of binder pitch of isostatic graphite product, comprising the following steps: A, crushing, modified pitch is crushed to 3-5 μm, B, mixing at room temperature, the modified pitch dry powder in step A is mixed with petroleum coke powder into mixing equipment, C, temperature mixing, the mixed dry powder in step B is put into mixing equipment and is mixed, and is extruded and crushed for several times in the mixing process.The purpose of the present application is to solve or at least alleviate the problem that the increase of the amount of binder pitch in the current isostatic graphite production process increases the difficulty of baking, and the qualified rate of baking is low, to provide a method for reducing the amount of binder pitch of isostatic graphite product.

Description

Technical Field

[0001] This invention belongs to the field of graphite product manufacturing technology, and particularly relates to a method for reducing the amount of asphalt used as a binder in isostatic graphite products. Background Technology

[0002] In the isostatic graphite production process, a common kneading process involves preheating the pre-mixed petroleum coke powder to a certain temperature and then adding it to a kneading pot. Liquid modified asphalt (softening point around 105℃) is then added to the kneading pot and mixed. Since the mixing of liquid asphalt and petroleum coke powder requires a process, the petroleum coke powder that comes into contact with the modified asphalt first will preferentially adsorb the binder asphalt. To avoid differences in asphalt content between the earlier and later contacted portions, the amount of modified asphalt needs to be increased (more than 30%). However, this increased asphalt content results in some asphalt remaining in a free state and not participating in wetting and binding. Increasing the amount of binder asphalt also increases the difficulty of calcination, leading to a lower calcination pass rate. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art, solve or at least alleviate the problem that the increased amount of binder bitumen in the current isostatic graphite production process increases the difficulty of calcination and results in a low calcination qualification rate, and to provide a method for reducing the amount of binder bitumen in isostatic graphite products.

[0004] This invention is achieved through the following technical solution: A method for reducing the amount of bitumen used in binders of isostatically pressed graphite products includes the following steps: A. Crushing: The modified asphalt is crushed to 3-5μm to obtain modified asphalt dry powder; B. Mixing at room temperature: The modified asphalt dry powder from step A and the petroleum coke powder are put into a mixing equipment for mixing to obtain mixed dry powder. The mass ratio of petroleum coke powder to modified asphalt dry powder is 2.8-3.4:1. C. Heating and kneading: The mixed dry powder from step B is placed into a kneading device for kneading. During the kneading process, it undergoes multiple compressions and crushings to obtain a kneaded paste.

[0005] To further realize the present invention, the following technical solutions may be preferred: Preferably, the mixing device includes a mixing hopper, a mixing shaft, and a guide plate; The mixing hopper has a frustum-shaped shell at the bottom, which is larger at the top and smaller at the bottom, and a convex arc-shaped longitudinal section at the top. The mixing hopper transitions smoothly between the bottom and top. A vertical feed pipe is provided at the top of the mixing hopper, and the lower end of the feed pipe is connected to the inside of the mixing hopper. A baffle is provided at the bottom of the mixing hopper, and the longitudinal section of the baffle is convex arc-shaped. The upper surface of the baffle is attached to the bottom surface of the mixing hopper. The mixing shaft is rotatably mounted on the mixing hopper and coaxial with the mixing hopper. Multiple stirring rods are fixedly arranged on the mixing shaft. The stirring rods are arranged radially along the mixing shaft. A stirring plate is fixedly mounted on the end of the stirring rod away from the mixing shaft. The stirring plate is flat and extends to the inner wall of the mixing hopper on the side away from the mixing shaft. The stirring plate is inclined and slides against the inner wall of the mixing hopper. The guide plate is circular and coaxially fixed inside the mixing hopper. The outer circumference of the guide plate is located at the connection between the upper and lower parts of the mixing hopper. There is a gap between the outer circumference of the guide plate and the inner wall of the mixing hopper. There is also a gap between the inner circumference of the guide plate and the outer circumference of the mixing shaft. The height of the middle part of the guide plate is lower than the height of the outer circumference of the guide plate.

[0006] Preferably, the mixing shaft includes an upper shaft and a lower shaft, which are coaxially arranged. The upper end of the lower shaft is rotatably fitted inside the lower end of the upper shaft. The upper shaft is cylindrical, and the lower shaft is a frustum-shaped shaft with a smaller upper section and a larger lower section. The rotational speed of the lower shaft is greater than that of the upper shaft.

[0007] Preferably, the mixing equipment further includes a storage tank, the lower part of which is cylindrical, and the upper end of which is connected to the lower outer side of the mixing hopper. A positioning plate is fixedly installed inside the storage tank, and a spring is installed between the positioning plate and the baffle. The upper and lower ends of the spring abut against the baffle and the positioning plate, respectively. A feeding shaft is coaxially arranged inside the storage hopper. The upper end of the feeding shaft is driven to the lower shaft, and a spiral feeding blade is provided on the lower part of the feeding shaft located at the bottom of the storage hopper.

[0008] Preferably, the kneading device includes a kneading shaft, a kneading tube, and an air guide pipe. The kneading shaft, kneading tube, and air guide pipe are arranged coaxially from the inside to the outside. A spiral kneading paddle is provided on the outer circumference of the kneading shaft. A heating device is provided inside both the kneading shaft and the kneading tube. A concave air guide groove is provided on the outer circumference of the kneading tube along its length. An upward feed pipe is provided at the front of the kneading tube, and a downward discharge pipe is provided at the rear of the kneading tube. A sealed cavity is formed between the air guide pipe and the kneading tube. An air inlet pipe and an air outlet pipe are respectively provided at the front and rear ends of the sealed cavity. Both the air inlet pipe and the air outlet pipe are connected to a cold air pipeline network.

[0009] Preferably, the heating device inside the mixing shaft is arranged along its length; The number of heating devices inside the kneading tube is multiple, and the multiple heating devices are evenly distributed around the circumference and embedded in the circumferential side wall of the kneading tube.

[0010] Preferably, the kneading tube includes multiple kneading sections, and a dispersing section is provided between any two adjacent kneading sections. Adjacent kneading sections and dispersing sections are axially connected, and the length of the dispersing section is less than the length of the kneading section. The heating device is fitted into the circumferential sidewall of the kneading section, and a conductive device is provided in the circumferential sidewall of the dispersing section. The heating devices in two adjacent kneading sections are electrically connected through the conductive device in the dispersing section.

[0011] Preferably, the air guide tube includes an air guide section and an air gathering section. The number of air guide sections and kneading sections are equal and they are arranged in a one-to-one correspondence. The number of air gathering sections and dispersing sections are opposite and they are arranged in a one-to-one correspondence. The inner diameter of the air guide section is smaller than the inner diameter of the air gathering section. Adjacent kneading sections and dispersing sections are connected by threaded fitting. The gas-gathering section is equipped with an exhaust pipe, which is located on the upper side of the gas-gathering section. The lower end of the exhaust pipe passes through the gas-gathering section and connects to the dispersing section, while the upper end of the exhaust pipe connects to the negative pressure pipeline network.

[0012] Preferably, the mixing shaft includes a meshing section and a feeding section. The number of meshing sections and mixing sections are equal and they are arranged in a one-to-one correspondence. The number of feeding sections and dispersing sections are opposite and they are arranged in a one-to-one correspondence. The helical pitch of the mixing paddle in the front meshing section is greater than that of the mixing paddle in the rear meshing section. The diameter of the mixing paddle in the feeding section is greater than that of the mixing paddle in the meshing section. The edge of the mixing paddle in the feeding section is flexible. The feeding section is arranged with several crushing components along its axial direction. Each crushing component includes a fixed hammer and a pendulum hammer. Both the fixed hammer and the pendulum hammer include a rod and a hammer body. The rod of the fixed hammer is arranged radially along the feeding section. One end of the rod of the fixed hammer is fixedly connected to the feeding section, and the other end is fixedly connected to the hammer body. The rod of the pendulum hammer is arranged radially along the feeding section. One end of the rod of the pendulum hammer is hinged to the outer circumference of the feeding section, and the other end is fixedly connected to the hammer body.

[0013] Preferably, the mixing tube further includes an outlet section, the air guide pipe further includes an air outlet section, and the mixing shaft further includes a material discharge section. Both the outlet section and the air outlet section are cylindrical with open front ends. The material discharge pipe is located below the outlet section, with its upper end connected to the outlet section and its lower end passing downward through the air outlet section. The outlet section is axially inserted into the adjacent mixing section, and the air outlet section is connected to the adjacent air guide section via a connecting sleeve. One end of the connecting sleeve is rotatably fitted onto the outer wall of the air outlet section, and the other end extends axially outward from the air outlet section and is threaded onto the outer wall of the adjacent air guide section. One end of the material discharge section is axially inserted into the adjacent meshing section, and the other end is rotatably fitted onto the bottom surface of the outlet section. A spring is provided between the bottom surface of the outlet section and the material discharge section.

[0014] The beneficial effects of the present invention through the above technical solution are: In this invention, petroleum coke powder and modified asphalt dry powder are mixed and coated. First, the modified asphalt is crushed into fine powder of 3-5 μm and then dry-mixed with the petroleum coke powder at room temperature to ensure thorough mixing. Then, the temperature is gradually increased and the mixture is kneaded to achieve uniform coating and wetting of the petroleum coke powder by the asphalt. While maintaining the kneading effect, the amount of modified asphalt used can be reduced by 6-8%. This reduction in modified asphalt usage improves the calcination qualification rate. Without affecting isostatic pressing and product quality, this process reduces the amount of modified asphalt used from 30-32% to 23-26%, and increases the calcination qualification rate by 10%.

[0015] After the mixing equipment and kneading equipment in this invention are connected, continuous automated production can be achieved while ensuring the uniformity of mixing.

[0016] The mixing equipment of this invention is equipped with heating devices inside both the mixing shaft and the mixing tube, achieving synchronous internal and external heating and improving heat transfer efficiency. The mixing tube includes a mixing section and a dispersing section. The dispersing section is added after extrusion to disperse the compacted material. The inner wall of the dispersing section is serrated, which facilitates material dispersion. The mixing shaft includes a meshing section and a feeding section, changing from a single-pass to a multi-pass series connection. The feeding section is located between the two meshing sections, and it works in conjunction with the dispersing section to achieve multiple extrusions. An air guide pipe is installed outside the mixing tube to circulate cold air during mixing. Combined with the heating device, this enables forced cooling for precise temperature control. While ensuring the wetting and binding properties of petroleum coke powder on asphalt, the free asphalt in the paste is minimized, resulting in a significant reduction in the amount of modified asphalt used. The paste with reduced free asphalt, after crushing and isostatic pressing, exhibits a significantly improved calcination qualification rate due to the reduced volatile matter content. Attached Figure Description

[0017] Figure 1 This is a process flow diagram of the present invention; Figure 2 This is a schematic diagram of the structure of the mixing equipment and kneading equipment of the present invention; Figure 3 This is a schematic diagram of the mixing equipment of the present invention; Figure 4 This is a structural cross-sectional view of the mixing equipment of the present invention; Figure 5 This is a schematic diagram of the mixing shaft of the present invention; Figure 6 This is a cross-sectional view of the mixing shaft of the present invention; Figure 7 This is a schematic diagram of the kneading device of the present invention; Figure 8 This is one of the structural cross-sectional views of the kneading device of the present invention; Figure 9 This is a second structural cross-sectional view of the kneading device of the present invention; Figure 10 For the present invention Figure 8 Enlarged view of point A in the middle; Figure 11 This is a schematic diagram of the mixing shaft of the present invention; Figure 12 This is a schematic diagram of the structure of the dispersing section of the present invention; Figure 13 This is a schematic diagram of the air duct structure of the present invention; Figure 14 This is a schematic diagram of the structure of the outlet section, air outlet section, and material outlet section of the present invention; Figure 15 For the present invention Figure 14 Structural sectional view; Figure 16 This is a schematic diagram of the heating device within the kneading section of the present invention. Wherein: 1-mixing hopper; 2-mixing shaft; 3-guide plate; 4-baffle; 5-stirring rod; 6-stirring plate; 7-storage bucket; 8-positioning plate; 9-feeding shaft; 10-feeding blade; 11-kneading shaft; 12-kneading pipe; 13-air guide pipe; 14-kneading paddle; 15-heating device; 16-exhaust pipe; 17-fixed hammer; 18-pendulum hammer; 19-connecting sleeve; 20-feeding pipe; 21-discharge pipe; 201-upper shaft; 202-lower shaft; 111-meshing section; 112-feeding section; 113-discharge section; 121-kneading section; 122-dispersing section; 123-outlet section; 131-air guide section; 132-air gathering section; 133-air outlet section. Implementation

[0018] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0020] like Figures 1-16As shown, a method for reducing the amount of bitumen used in the binder of isostatically pressed graphite products includes the following steps: A. Crushing: The modified asphalt is crushed to 3-5μm to obtain modified asphalt dry powder; B. Mixing at room temperature: The modified asphalt dry powder from step A and the petroleum coke powder are put into a mixing equipment for mixing to obtain mixed dry powder. The mass ratio of petroleum coke powder to modified asphalt dry powder is 2.8-3.4:1. C. Heating and kneading: The mixed dry powder from step B is placed into a kneading device for kneading. During the kneading process, it undergoes multiple compressions and crushings to obtain a kneaded paste.

[0021] In this invention, petroleum coke powder and modified asphalt dry powder are mixed and coated. First, the modified asphalt is crushed into fine powder of 3-5 μm and then dry-mixed with the petroleum coke powder at room temperature to ensure thorough mixing. Then, the temperature is gradually increased and the mixture is kneaded to achieve uniform coating and wetting of the petroleum coke powder by the asphalt. While maintaining the kneading effect, the amount of modified asphalt used can be reduced by 6-8%. This reduction in modified asphalt usage improves the calcination qualification rate. Without affecting isostatic pressing and product quality, this process reduces the amount of modified asphalt used from 30-32% to 23-26%, and increases the calcination qualification rate by 10%.

[0022] After the mixing equipment is connected to the kneading equipment, continuous automated production can be achieved while ensuring the uniformity of mixing.

[0023] The mixing equipment includes a mixing hopper 1, a mixing shaft 2, and a guide plate 3; The mixing hopper 1 has a frustum-shaped shell at the bottom, which is larger at the top and smaller at the bottom, and a longitudinal section at the top that is convex. The lower part of the mixing hopper 1 and the upper part of the mixing hopper 1 are smoothly connected. A vertical feeding pipe is provided at the upper part of the mixing hopper 1, and the lower end of the feeding pipe is connected to the inside of the mixing hopper 1. A baffle 4 is provided at the lower end of the mixing hopper 1. The longitudinal section of the baffle 4 is convex. The upper surface of the baffle 4 is attached to the lower end face of the mixing hopper 1. The mixing shaft 2 is rotatably mounted on the mixing hopper 1 and is coaxial with the mixing hopper 1. Multiple stirring rods 5 are fixedly arranged on the mixing shaft 2. The stirring rods 5 are arranged radially along the mixing shaft 2. A stirring plate 6 is fixedly mounted on the end of the stirring rod 5 away from the mixing shaft 2. The stirring plate 6 is flat and extends to the inner wall of the mixing hopper 1 on the side away from the mixing shaft 2. The stirring plate 6 is inclined and slides against the inner wall of the mixing hopper 1. The guide plate 3 is circular and coaxially fixed inside the mixing hopper 1. The outer circumference of the guide plate 3 is located at the connection between the upper and lower parts of the mixing hopper 1. There is a gap between the outer circumference of the guide plate 3 and the inner wall of the mixing hopper 1. There is a gap between the inner circumference of the guide plate 3 and the outer circumference of the mixing shaft 2. The height of the middle part of the guide plate 3 is lower than the height of the outer part of the guide plate 3.

[0024] After entering the mixing hopper 1, the material falls onto the guide plate 3 and then from the middle of the guide plate 3 down the mixing shaft 2 to the bottom of the mixing hopper 1. The mixing shaft 2 drives the stirring plate 6 to rotate, causing the material to rise along the inner wall of the mixing hopper 1. When the material reaches the junction of the lower and upper parts of the mixing hopper 1, it falls onto the guide plate 3. The material is repeatedly stirred in the mixing hopper 1, thereby improving the mixing effect.

[0025] To ensure that the material can move upward along the mixing hopper 1, the mixing shaft 2 includes an upper shaft 201 and a lower shaft 202. The upper shaft 201 and the lower shaft 202 are coaxially arranged. The upper end of the lower shaft 202 is rotatably fitted inside the lower end of the upper shaft 201. The upper shaft 201 is cylindrical, and the lower shaft 202 is a frustum shape with a smaller upper part and a larger lower part. The rotational speed of the lower shaft 202 is greater than the rotational speed of the upper shaft 201.

[0026] To facilitate continuous production, the mixing equipment also includes a storage tank 7. The lower part of the storage tank 7 is cylindrical, and the upper end of the storage tank 7 is connected to the lower outer side of the mixing hopper 1. A positioning plate 8 is fixedly installed inside the storage tank 7. A spring is installed between the positioning plate 8 and the baffle 4. The upper and lower ends of the spring abut against the baffle 4 and the positioning plate 8, respectively. When the weight of the material falling above the baffle 4 is greater than the elastic force of the spring, the baffle 4 moves down, and the material in the mixing hopper 1 falls into the storage tank 7. After the material falls, the baffle 4 moves up, sealing the lower part of the mixing hopper 1 and continuing the mixing process. A feeding shaft 9 is coaxially arranged inside the storage hopper 7. The upper end of the feeding shaft 9 is connected to the lower shaft 202. A spiral feeding blade 10 is arranged on the lower part of the feeding shaft 9 located at the lower part of the storage hopper 7. The feeding blade 10 rotates continuously, so that the material at the lower part of the storage hopper 7 enters the mixing equipment stably.

[0027] The kneading equipment includes a kneading shaft 11, a kneading tube 12, and an air guide pipe 13. The kneading shaft 11, the kneading tube 12, and the air guide pipe 13 are arranged coaxially from the inside to the outside. A spiral kneading paddle 14 is provided on the outer circumference of the kneading shaft 11. A heating device 15 is provided inside both the kneading shaft 11 and the kneading tube 12. A concave air guide groove is provided on the outer circumference of the kneading tube 12 along its length. An upward feed pipe 20 is provided at the front of the kneading tube 12, and a downward discharge pipe 21 is provided at the rear of the kneading tube 12. A closed cavity is formed between the air guide pipe 13 and the kneading tube 12. An air inlet pipe and an air outlet pipe are provided at the front and rear ends of the closed cavity, respectively. Both the air inlet pipe and the air outlet pipe are connected to the cold air pipeline network.

[0028] The mixing equipment of this invention is equipped with heating devices 15 inside both the mixing shaft 11 and the mixing tube 12 to achieve synchronous internal and external heating and improve heat transfer efficiency. The mixing tube 12 includes a mixing section 121 and a dispersing section 122. The dispersing section 122 is added after extrusion to disperse the compacted material. The inner wall of the dispersing section 122 is serrated, which is beneficial for material dispersion. The mixing shaft 11 includes a meshing section 111 and a feeding section 112. It is changed from a single-pass to a multi-pass series connection. The feeding section 112 is located between the two sets of meshing sections 111. The feeding section 112 cooperates with the dispersing section 122 to achieve multiple extrusions. A gas guide pipe 13 is provided outside the mixing tube 12 to pass cold air during mixing. In conjunction with the heating device 15, it can achieve forced cooling for precise temperature control. While ensuring the wetting and binding properties of petroleum coke powder on asphalt, the free asphalt in the paste is reduced to the maximum extent, resulting in a significant reduction in the amount of modified asphalt used. After the paste containing less free asphalt is crushed and isostatically pressed, the calcination qualification rate is greatly improved due to the reduction in volatile matter.

[0029] In order to optimize the product structure, in this embodiment, the heating device 15 inside the mixing shaft 11 is arranged along its length. The number of heating devices 15 inside the kneading tube 12 is multiple, and the multiple heating devices 15 are evenly distributed around the circumference and embedded in the circumferential side wall of the kneading tube 12.

[0030] The kneading tube 12 includes multiple kneading sections 121. A dispersing section 122 is provided between any two adjacent kneading sections 121. Adjacent kneading sections 121 and dispersing sections 122 are axially inserted together. The length of the dispersing section 122 is less than the length of the kneading section 121. The heating device 15 is fitted into the circumferential side wall of the kneading section 121, and a conductive device is provided in the circumferential side wall of the dispersing section 122. The heating devices 15 in two adjacent kneading sections 121 are electrically connected through the conductive device in the dispersing section 122.

[0031] The kneading tube 12 is easy to assemble, the kneading section 121 is heated to ensure the kneading effect, and the dispersing section 122 is not heated to improve the dispersing effect.

[0032] The air guide pipe 13 includes an air guide section 131 and an air gathering section 132. The number of air guide sections 131 and kneading sections 121 are equal and they are arranged in a one-to-one correspondence. The number of air gathering sections 132 and dispersing sections 122 are opposite and they are arranged in a one-to-one correspondence. The inner diameter of the air guide section 131 is smaller than the inner diameter of the air gathering section 132. Adjacent kneading sections 121 and dispersing sections 122 are connected by threaded fitting. The air gathering section 132 contains more cold air to improve the cooling effect of the dispersing section 122. The gas-gathering section 132 is equipped with an exhaust pipe 16, which is located on the upper side of the gas-gathering section 132. The lower end of the exhaust pipe 16 passes through the gas-gathering section 132 and connects to the dispersing section 122. The upper end of the exhaust pipe 16 connects to the negative pressure pipe network. During mixing, some volatile gases will be released. These volatile gases will cause pollution when released into the air. The volatile gases are absorbed by the negative pressure pipe network to avoid pollution.

[0033] The mixing shaft 11 includes an engagement section 111 and a feeding section 112. The number of engagement sections 111 and mixing sections 121 are equal and they are arranged in a one-to-one correspondence. The number of feeding sections 112 and dispersing sections 122 are opposite and they are arranged in a one-to-one correspondence. The screw pitch of the mixing paddle 14 in the front engagement section 111 is greater than that in the rear engagement section 111. The diameter of the mixing paddle 14 in the feeding section 112 is greater than that in the engagement section 111. The edges of the mixing paddle 14 in the feeding section 112 are flexible. The degree of extrusion is gradually increased to promote asphalt impregnation. The feeding section 112 is arranged with several crushing components along its axial direction. The crushing components include a fixed hammer 17 and a pendulum hammer 18. Both the fixed hammer 17 and the pendulum hammer 18 include a rod and a hammer. The rod of the fixed hammer 17 is arranged radially along the feeding section 112. One end of the rod of the fixed hammer 17 is fixedly connected to the feeding section 112, and the other end is fixedly connected to the hammer. The rod of the pendulum hammer 18 is arranged radially along the feeding section 112. One end of the rod of the pendulum hammer 18 is hinged to the outer circumference of the feeding section 112, and the other end is fixedly connected to the hammer. The pendulum hammer 18 swings with the rotation of the feeding section 112. The hammer of the pendulum hammer 18 continuously strikes the hammer of the fixed hammer 17, continuously striking and pounding the material inside, thereby improving the crushing effect.

[0034] For ease of installation and operation, the mixing tube 12 also includes an outlet section 123, the air guide tube 13 also includes an air outlet section 133, and the mixing shaft 11 also includes a discharge section 113. Both the outlet section 123 and the air outlet section 133 are cylindrical with open front ends. The discharge pipe 21 is located below the outlet section 123, with its upper end connected to the outlet section 123 and its lower end passing downward through the air outlet section 133. The outlet section 123 is axially inserted into the adjacent mixing section 121, and the air outlet section 133 is connected to the adjacent mixing section 121 via a connecting sleeve 19. The adjacent air guide section 131 has a connecting sleeve 19 with one end rotatably fitted onto the outer wall of the air outlet section 133 and the other end axially extending outward from the air outlet section 133 and threadedly fitted onto the outer wall of the adjacent air guide section 131. One end of the discharge section 113 is axially inserted into the adjacent meshing section 111, and the other end is rotatably fitted onto the bottom surface of the outlet section 123. A spring is provided between the bottom surface of the outlet section 123 and the discharge section 113. The inner mixing shaft 11 and mixing tube 12 are both axially inserted, and the air guide tube 13 is threadedly fitted for assembly, which is convenient for installation and positioning.

[0035] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for reducing the amount of bitumen used as a binder in isostatically pressed graphite products, characterized in that, Includes the following steps: A. Crushing: The modified asphalt is crushed to 3-5µm to obtain modified asphalt dry powder; B. Mixing at room temperature: The modified asphalt dry powder from step A and the petroleum coke powder are put into a mixing equipment for mixing to obtain mixed dry powder. The mass ratio of petroleum coke powder to modified asphalt dry powder is 2.8-3.4:

1. C. Heating and kneading: The mixed dry powder from step B is placed into a kneading device for kneading. The kneading device includes a kneading shaft (11) and a kneading tube (12). Both the kneading shaft (11) and the kneading tube (12) are equipped with heating devices (15). The kneading shaft (11) includes a feeding section (112). The feeding section (112) is arranged in an array along its axial direction with several crushing components. The crushing components include a fixed hammer (17) and a pendulum hammer (18). The rod of the hammer (17) is arranged radially along the feeding section (112). One end of the rod of the fixed hammer (17) is fixedly connected to the feeding section (112), and the other end is fixedly connected to the hammer body. The rod of the pendulum (18) is arranged radially along the feeding section (112). One end of the rod of the pendulum (18) is hinged to the outer circumference of the feeding section (112), and the other end is fixedly connected to the hammer body. During the mixing and kneading process of the dry powder, after multiple extrusions and crushing by the crushing component, a kneaded paste is obtained.

2. The method for reducing the amount of bitumen used in the binder of isostatic graphite products according to claim 1, characterized in that, The mixing equipment includes a mixing hopper (1), a mixing shaft (2), and a guide plate (3); The mixing hopper (1) has a frustum-shaped shell at the bottom, which is larger at the top and smaller at the bottom, and a longitudinal section at the top that is convex. The mixing hopper (1) has a smooth transition between the bottom and top. A vertical feeding pipe is provided at the top of the mixing hopper (1), and the lower end of the feeding pipe is connected to the mixing hopper (1). A baffle (4) is provided at the bottom of the mixing hopper (1), and the longitudinal section of the baffle (4) is convex. The upper surface of the baffle (4) is attached to the lower end face of the mixing hopper (1). The mixing shaft (2) is rotatably mounted on the mixing hopper (1) and coaxially mounted with the mixing hopper (1). The mixing shaft (2) is fixedly arrayed with multiple stirring rods (5). The stirring rods (5) are arranged radially along the mixing shaft (2). A stirring plate (6) is fixedly mounted at the end of the stirring rod (5) away from the mixing shaft (2). The stirring plate (6) is flat and extends to the inner wall of the mixing hopper (1) on the side away from the mixing shaft (2). The stirring plate (6) is inclined and slides against the inner wall of the mixing hopper (1). The guide plate (3) is circular and coaxially fixed inside the mixing hopper (1). The outer circumference of the guide plate (3) is located at the connection between the upper part and the lower part of the mixing hopper (1). There is a gap between the outer circumference of the guide plate (3) and the inner wall of the mixing hopper (1). There is a gap between the inner circumference of the guide plate (3) and the outer circumference of the mixing shaft (2). The height of the middle part of the guide plate (3) is lower than the height of the outer part of the guide plate (3).

3. The method for reducing the amount of bitumen used in the binder of isostatic graphite products according to claim 2, characterized in that, The mixing shaft (2) includes an upper shaft (201) and a lower shaft (202). The upper shaft (201) and the lower shaft (202) are coaxially arranged. The upper end of the lower shaft (202) is rotatably fitted inside the lower end of the upper shaft (201). The upper shaft (201) is cylindrical, and the lower shaft (202) is a frustum shape with a smaller upper part and a larger lower part. The rotational speed of the lower shaft (202) is greater than that of the upper shaft (201).

4. The method for reducing the amount of bitumen used in the binder of isostatic graphite products according to claim 3, characterized in that, The mixing equipment also includes a storage tank (7), the lower part of which is in the shape of a round tube, and the upper end of which is connected to the lower outer side of the mixing hopper (1). A positioning plate (8) is fixedly installed inside the storage tank (7), and a spring is installed between the positioning plate (8) and the baffle (4). The upper and lower ends of the spring abut against the baffle (4) and the positioning plate (8) respectively. A feeding shaft (9) is coaxially arranged inside the storage hopper (7). The upper end of the feeding shaft (9) is connected to the lower shaft (202). A spiral feeding blade (10) is provided on the lower part of the feeding shaft (9) located at the lower part of the storage hopper (7).

5. The method for reducing the amount of bitumen used in the binder of isostatic graphite products according to claim 1, characterized in that, The kneading device also includes an air guide pipe (13). The kneading shaft (11), kneading tube (12) and air guide pipe (13) are arranged coaxially from the inside to the outside. A spiral kneading paddle (14) is provided on the outer circumference of the kneading shaft (11). A concave air guide groove is provided on the outer circumference of the kneading tube (12) along its length. An upward feed pipe (20) is provided at the front of the kneading tube (12), and a downward discharge pipe (21) is provided at the rear of the kneading tube (12). A closed cavity is formed between the air guide pipe (13) and the kneading tube (12). An air inlet pipe and an air outlet pipe are provided at the front and rear ends of the closed cavity, respectively. Both the air inlet pipe and the air outlet pipe are connected to the cold air pipeline network.

6. The method for reducing the amount of bitumen used in the binder of isostatic graphite products according to claim 5, characterized in that, The heating device (15) inside the mixing shaft (11) is arranged along its length; The number of heating devices (15) inside the kneading tube (12) is multiple, and the multiple heating devices (15) are evenly distributed around the circumference and embedded in the circumferential side wall of the kneading tube (12).

7. The method for reducing the amount of bitumen used in the binder of isostatic graphite products according to claim 5, characterized in that, The kneading tube (12) includes multiple kneading sections (121), and a dispersing section (122) is provided between any two adjacent kneading sections (121). Adjacent kneading sections (121) and dispersing sections (122) are axially connected. The length of the dispersing section (122) is less than the length of the kneading section (121). The heating device (15) is fitted into the circumferential sidewall of the kneading section (121), and a conductive device is provided in the circumferential sidewall of the dispersing section (122). The heating devices (15) in two adjacent kneading sections (121) are electrically connected through the conductive device in the dispersing section (122).

8. The method for reducing the amount of bitumen used in the binder of isostatic graphite products according to claim 7, characterized in that, The air guide tube (13) includes an air guide section (131) and an air gathering section (132). The number of air guide sections (131) and kneading sections (121) are equal and they are arranged in a one-to-one correspondence. The number of air gathering sections (132) and dispersing sections (122) are equal and they are arranged in a one-to-one correspondence. The inner diameter of the air guide section (131) is smaller than the inner diameter of the air gathering section (132). The gas-gathering section (132) is provided with an exhaust pipe (16). The exhaust pipe (16) is located on the upper side of the gas-gathering section (132). The lower end of the exhaust pipe (16) passes through the gas-gathering section (132) and is connected to the dispersing section (122). The upper end of the exhaust pipe (16) is connected to the negative pressure pipeline network.

9. A method for reducing the amount of bitumen used in the binder of isostatically pressed graphite products according to claim 7, characterized in that, The mixing shaft (11) also includes a meshing section (111), the number of meshing sections (111) and mixing sections (121) are equal and they are arranged in a one-to-one correspondence. The number of feeding sections (112) and dispersing sections (122) are equal and they are arranged in a one-to-one correspondence. The helical pitch of the mixing paddle (14) in the front meshing section (111) is greater than the helical pitch of the mixing paddle (14) in the rear meshing section (111). The diameter of the mixing paddle (14) in the feeding section (112) is greater than the diameter of the mixing paddle (14) in the meshing section (111). The edge of the mixing paddle (14) in the feeding section (112) is flexible.

10. A method for reducing the amount of bitumen used in the binder of isostatically pressed graphite products according to claim 9, characterized in that, The mixing tube (12) further includes an outlet section (123), the air guide tube (13) further includes an air outlet section (133), and the mixing shaft (11) further includes a discharge section (113). Both the outlet section (123) and the air outlet section (133) are cylindrical with open front ends. The discharge pipe (21) is located below the outlet section (123), with its upper end connected to the outlet section (123) and its lower end passing downwards through the air outlet section (133). The outlet section (123) is axially inserted into the adjacent mixing section. 121), the air outlet section (133) is connected to the adjacent air guide section (131) through the connecting sleeve (19). One end of the connecting sleeve (19) is rotatably fitted to the outer wall of the air outlet section (133), and the other end extends axially outward from the air outlet section (133) and is threadedly fitted to the outer wall of the adjacent air guide section (131). One end of the discharge section (113) is axially inserted into the adjacent meshing section (111), and the other end is rotatably fitted to the bottom surface of the outlet section (123). A spring is provided between the bottom surface of the outlet section (123) and the discharge section (113).

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