Preparation method of precoated sand with high heat resistance

Abstract

The invention relates to a preparation method of high-heat-resistance precoated sand applied to the field of castings, which is characterized in that zinc borate is added into crude sand, and the heat resistance of the precoated sand is effectively improved by utilizing the characteristic that the zinc borate forms a glassy state inorganic coating at high temperature; and an automatic weighing and feeding device is additionally arranged on the efficient runner wheel sand mixer to effectively improve the sand mixing effect, a magnetic disc intermittently repels a full magnetic disc under the driving action of a stand column, so that two porous leakage plates move oppositely under the hydraulic action, auxiliary materials are intermittently and uniformly discharged, the sand mixing effect can be improved, and the sand mixing efficiency is improved. In addition, in the falling process of various auxiliary materials, the auxiliary materials are further fully premixed through the rebounding device and the dispersing cone, the mixing time of the auxiliary materials and crude sand is effectively saved, and the sand mixing effect can be further effectively improved.

Description

Technical Field

[0001] The invention relates to a method for preparing high heat-resistant coated sand, and in particular to a method for preparing high heat-resistant coated sand used in the field of castings. Background Art

[0002] Coated sand plays an important role in castings and has a significant impact on the cost and mechanical properties of castings. The shell casting process is low-cost, high-efficiency, and easy to learn, but it is easy to "learn once, but fail once poured". Because the coated sand shell process is prone to shell cracking, it is easy to "run away" during stacked box casting, and the coated sand shell mold falls off prematurely, causing "hot cracking" and "running away" in the casting.

[0003] In order to solve the problem of poor heat resistance of coated sand, a certain coated sand in the market adopts the design of adding heat-resistant auxiliary materials, which has a certain market share.

[0004] The Chinese patent CN201010270015.1 specification discloses a coated sand, which includes raw sand, a binder, a curing agent and a coupling agent, wherein the amount of the curing agent is 40-60% of the total mass of the binder, the amount of the coupling agent is 0.2-0.5% of the total mass of the binder, the amount of the binder is 1-1.5% of the total mass of the raw sand, the particle size of the raw sand is 100-150 meshes, the components of the raw sand and their weight proportions are: yellow sand 70-80, diatomaceous earth 10-20, high temperature cement 5-15, the components of the binder and their weight proportions are: thermosetting phenolic resin 5-10, thermoplastic phenolic resin 90-95. This solution not only has good heat resistance and small roughness, but also has good air permeability and can avoid sand sticking on the casting.

[0005] The specification of Chinese patent CN202110386935.8 discloses a high-strength and high-heat-resistant coated sand and a preparation method thereof. The scheme includes raw sand, a tackifier, a resin nano-modified synergist, and a composite reinforcing agent, wherein the raw sand includes quartz sand with a fineness of less than 40 meshes; the tackifier includes a silane coupling agent; the resin nano-modified synergist builds a heat-conducting network through whisker-like carbon nanotubes and graphite microspheres; and the composite reinforcing agent includes acidic and alkaline oxide micropowders. A high-strength and high-heat-resistant coated sand and a preparation method thereof provided by the present invention utilize the principle of multi-component synergistic enhancement, and the obtained coated sand mold has the advantages of high bonding strength, reasonable porosity, not easy to shell, good high-temperature impact resistance, and long heat-resistant time. Its structural feature is that the independent spherical graphite particles are interconnected by whisker-like carbon nanotubes, which not only enhances the resin matrix, but also forms a synergistic effect of a continuous heat-conducting network, thereby improving the overall heat dissipation capacity and heat-resistant time of the coated sand.

[0006] Although the existing coated sands improve their heat resistance by adding heat-resistant auxiliary materials, the heat resistance of the coated sand is also affected during the production and preparation process due to unsatisfactory sand mixing effect. In addition, the existing sand mixers take a long time to mix the sand, and the sand mixing effect does not meet the requirements. Summary of the invention

[0007] In view of the above-mentioned prior art, the technical problem to be solved by the present invention is to improve the sand mixing effect of raw sand and heat-resistant auxiliary materials.

[0008] In order to solve the above problems, the present invention provides a method for preparing high heat-resistant coated sand, comprising the following preparation steps: S1. First, heat the raw sand in the raw material bin to increase its temperature, then put the heated raw sand into the roasting furnace for roasting to obtain roasted sand. After roasting, the raw sand is passed through a heat exchanger, and the heat exchanger recovers the heat to heat the raw sand. Then, the roasted sand enters a cooling drum for cooling. The roasted sand after cooling is screened by a circular screen, and the screened roasted sand is transported to the preparation bin by a bucket elevator; S2. The roasted sand in the material preparation bin is put on a belt scale for weighing. The belt scale transports the roasted sand to the heater for heating. After heating, the roasted sand is put into a high-efficiency roller sand mixer. During the sand mixing process, phenolic resin, urotropine, calcium stearate, zinc borate and other auxiliary materials are put in according to the weight ratio. The weight ratio of the above auxiliary materials is: phenolic resin 2%-5%, urotropine 0.1%-2%, calcium stearate 0.1%-2%, zinc borate 2%-8%, and the weight ratio of the roasted sand is 100%; S3. After the sand mixing is completed, the coated sand is obtained, which is transported to the swing screen for screening. The screened coated sand is transported to the boiling cooling bed by the vibrating conveyor for cooling. The coated sand left after screening is put into the crushing screen for crushing and screening again, and then transported to the boiling cooling bed. After cooling, the coated sand is transported to the finished product silo to wait for filling.

[0009] As a further improvement of the present application, the particle size of the raw sand is 100-200 mesh, and the content of silicon dioxide in the raw sand is 96%-100%.

[0010] As a further improvement of the present application, the high-efficiency grinding wheel sand mixer in step S2 includes a column, the upper end of the high-efficiency grinding wheel sand mixer is connected to a dust cover, and one side of the dust cover is fixedly connected to a raw sand feeding pipe that penetrates the dust cover, the side of the dust cover away from the raw sand feeding pipe is fixedly connected to an auxiliary material bin, the inner wall of the auxiliary material bin is fixedly connected to a partition plate, and the bottom of the partition plate is fixedly connected to a bin bottom support, the partition plate isolates the interior of the auxiliary material bin into a plurality of bins, and the bin bottom support is located below each bin and an automatic weighing and batching scale body is installed, the dust cover is located below the auxiliary material bin and a pre-mixing chamber is opened on the inner wall, and a plurality of automatic weighing and batching scale bodies are connected to the pre-mixing chamber at the same time through a feed pipe, the inner wall of the dust cover located below the pre-mixing chamber is fixedly inlaid with a connecting pipe, and the inner wall of the connecting pipe is fixedly connected to an intermittent feeder, the dust cover is located below the connecting pipe and is also connected to a rebound feeding pipe, and the rebound feeding pipe The lower end is connected with a conical spreading pipe, a driving cavity is provided on the middle inner wall of the dust cover, and a driving shaft that runs through the bottom of the dust cover is rotatably connected at the middle position of the driving cavity, the lower end of the driving shaft is connected with a gear coupling, and the lower end of the gear coupling is fixedly connected with a cross plug that is plugged into the column, a turntable is fixedly sleeved on the side wall of the driving shaft located inside the driving cavity, a piston cavity is provided on the inner wall of the dust cover facing the turntable, and a piston is sealingly and slidably connected to the inner wall of the piston cavity, and a full magnetic disk that magnetically repels the turntable is fixedly connected to the side wall of the piston, and the automatic weighing and batching scale body is used to realize automatic weighing and delivery of auxiliary materials, effectively avoiding errors caused by manual delivery, and the rotation of the column drives the cross plug to rotate, and the cross plug then drives the driving shaft to rotate, and the auxiliary materials are intermittently delivered through the magnetic repulsion of the turntable on the full magnetic disk and the hydraulic action, effectively accelerating the sand mixing efficiency and effectively improving the sand mixing effect.

[0011] As a further improvement of the present application, the intermittent feeder includes a disc body, and a through opening is provided on the middle side wall of the disc body, and telescopic movable grooves are provided on the side walls on both sides of the through opening, and the inner wall of the telescopic movable groove is sealed and slidably connected with a porous leakage plate, and a plurality of symmetrically distributed elastic pull bands are fixedly connected between the porous leakage plate and the inner wall of the telescopic movable groove, and an annular hydraulic cavity connected to the piston cavity is provided on the inner wall of the disc body, and the interiors of the piston cavity and the annular hydraulic cavity are filled with hydraulic oil at the same time, and the rotation of the magnetic disk is utilized to intermittently repel the full magnetic disk, and the full magnetic disk relies on the hydraulic action to make the two porous leakage plates move in an offset manner, so as to realize intermittent and uniform discharge of materials, which can not only effectively prevent blockage, but also evenly feed the auxiliary materials into the original sand, effectively improving the full mixing effect of the original sand and the auxiliary materials.

[0012] As a further improvement and supplement to the present application, two porous leakage plates are distributed up and down, and the leakage ports on the two porous leakage plates are staggered. When the full magnetic disk squeezes the hydraulic oil each time, the two porous leakage plates move toward each other under hydraulic drive, so that the leakage ports will be aligned, and the auxiliary material will leak out from the leakage ports, thereby achieving intermittent and uniform feeding.

[0013] As another improvement of the present application, the turntable includes a diskless disk and a disk-equipped disk, and the diskless disk and the disk-equipped disk each occupy half of the turntable area. When the turntable rotates, the disk-equipped disk intermittently repels the full disk, so that the two porous leakage plates can discharge material intermittently. Moreover, the turntable is driven by a column to rotate, without the need for additional energy consumption, effectively saving costs.

[0014] As another improvement of the present application, the rebound feeding pipe includes multiple groups of rebounders and multiple groups of dispersion cones fixedly connected to the inner wall, and the multiple groups of rebounders and the multiple groups of dispersion cones are alternately arranged, and brackets are fixedly connected between the two sides of the dispersion cone and the inner wall of the rebound feeding pipe. When the auxiliary material falls into the rebound feeding pipe, the various auxiliary materials hit the rebounder, and the rebounder throws the auxiliary material upward. In this process, the various auxiliary materials are mixed with each other, thereby effectively improving the premixing effect, and when the auxiliary material hits the dispersion cone, the dispersion cone disperses the various auxiliary materials again, thereby further effectively improving the premixing effect.

[0015] As another improved supplement of the present application, the rebounder includes a rebound plate rotatably connected to the inner wall of the rebound feeding tube, and a flexible membrane is fixedly connected between the lower end of the rebound plate and the inner wall of the rebound feeding tube, and the space formed by the rebound plate and the flexible membrane is filled with an elastic net. When the auxiliary material falls and hits the rebound plate, the elastic force of the elastic net will cause the rebound plate to rebound the auxiliary material, and the auxiliary material will be dispersed upward under the action of the rebound. In this process, various auxiliary materials will be fully mixed, thereby playing an effective pre-mixing role.

[0016] In summary, by adding zinc borate to the original sand and utilizing the property of zinc borate to form a glassy inorganic coating at high temperature, the heat resistance of the coated sand can be effectively improved, and by adding an automatic weighing and feeding device to the high-efficiency roller sand mixer, the sand mixing effect can be effectively improved. The driving effect of the column is utilized to allow the magnetic disk to intermittently repel the full magnetic disk, so that the two porous leakage plates move toward each other under the action of hydraulic pressure, and then the auxiliary materials are intermittently and evenly discharged, which can not only improve the sand mixing effect, but also effectively prevent the occurrence of material blockage. In addition, in the process of falling of various auxiliary materials, the rebounder and dispersion cone are used to further fully pre-mix the auxiliary materials, which effectively saves the mixing time of the auxiliary materials and the original sand, and can also further effectively improve the sand mixing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a flow chart for the production and preparation of coated sand according to the first embodiment of the present application; Figure 2 A three-dimensional diagram of a high-efficiency grinding wheel sand mixer according to a first embodiment of the present application; Figure 3 This is a three-dimensional exploded view of a high-efficiency grinding wheel sand mixer according to the first embodiment of the present application; Figure 4A three-dimensional diagram of a dust cover according to a first embodiment of the present application; Figure 5 This is a front cross-sectional view of a dust cover according to a first embodiment of the present application; Figure 6 A top view of the connection relationship between the turntable and the intermittent feeder in the first embodiment of the present application; Figure 7 This is a three-dimensional diagram of an intermittent feeder according to the first embodiment of the present application; Figure 8 This is a position relationship diagram of two porous leakage plates in the first embodiment of the present application; Fig. 9 This is a state diagram of two porous leakage plates in the first embodiment of the present application when they are misaligned; Fig.10 This is a state diagram of two porous leakage plates in the first embodiment of the present application when they are aligned; Fig.11 This is a front cross-sectional view of the rebound-type feeding tube of the first embodiment of the present application.

[0018] Description of the numbers in the figure: 1 high-efficiency grinding wheel sand mixer, 101 column, 2 dust cover, 201 pre-mixing chamber, 202 driving chamber, 3 raw sand feeding pipe, 4 auxiliary material bin, 401 partition board, 402 bin bottom support, 5 automatic weighing and batching scale body, 6 rebound feeding pipe, 7 conical spreading pipe, 8 connecting pipe, 9 intermittent feeder, 901 plate, 902 port, 903 telescopic moving groove, 904 porous leakage plate, 905 elastic pull belt, 906 annular hydraulic chamber, 10 driving shaft, 11 gear coupling, 1101 cross plug, 12 turntable, 1201 without magnetic disk, 1202 with magnetic disk, 13 piston, 14 full magnetic disk, 15 rebounder, 1501 rebound plate, 1502 flexible membrane, 1503 elastic net, 16 dispersion cone, 17 bracket. DETAILED DESCRIPTION

[0019] Two implementation modes of the present application are described in detail below with reference to the accompanying drawings.

[0020] The first implementation method: Figure 1 Shown, comprising the following preparation steps: S1. First, heat the raw sand in the raw material bin to increase its temperature, then put the heated raw sand into the roasting furnace for roasting to obtain roasted sand. After roasting, the raw sand is passed through a heat exchanger, and the heat exchanger recovers the heat to heat the raw sand. Then, the roasted sand enters a cooling drum for cooling. The roasted sand after cooling is screened by a circular screen, and the screened roasted sand is transported to the preparation bin by a bucket elevator; S2, the roasted sand in the material preparation bin is put on the belt scale for weighing, and the belt scale transports the roasted sand to the heater for heating. After the heating is completed, the roasted sand is put into the high-efficiency roller sand mixer 1. During the sand mixing process, phenolic resin, urotropine, calcium stearate, zinc borate and other auxiliary materials are put in according to the weight ratio. The weight ratio of the above auxiliary materials is: phenolic resin 2%-5%, urotropine 0.1%-2%, calcium stearate 0.1%-2%, zinc borate 2%-8%, and the weight ratio of the roasted sand is 100%; The particle size of the raw sand is 100-200 mesh, and the content of silicon dioxide in the raw sand is 96%-100%; S3, after the sand mixing is completed, the coated sand is obtained, and the coated sand is transported to the swing screen for screening. The screened coated sand is transported to the boiling cooling bed by the vibrating conveyor for cooling, and the screened coated sand is put into the crushing screen for crushing and screening again, and then transported to the boiling cooling bed. After cooling, the coated sand is transported to the finished product silo to wait for filling; Figure 2 , 3 , 4 and 5 show that the high-efficiency grinding wheel sand mixer 1 in step S2 includes a column 101, a dust cover 2 is connected to the upper end of the high-efficiency grinding wheel sand mixer 1, and a raw sand feeding pipe 3 penetrating the dust cover 2 is fixedly connected to one side of the dust cover 2, an auxiliary material bin 4 is fixedly connected to the side of the dust cover 2 away from the raw sand feeding pipe 3, a partition plate 401 is fixedly connected to the inner wall of the auxiliary material bin 4, and a bin bottom support 402 is fixedly connected to the bottom of the partition plate 401, the partition plate 401 isolates the interior of the auxiliary material bin 4 into a plurality of bins, and the bin bottom support 402 is located below each bin and is equipped with an automatic The dynamic weighing batching scale body 5 (the specific model is selected according to actual needs and will not be described in detail here), the dust cover 2 is located below the auxiliary material bin 4, and the inner wall is provided with a pre-mixing chamber 201, and multiple automatic weighing batching scale bodies 5 are simultaneously connected to the pre-mixing chamber 201 through a feed pipe, and the inner wall of the dust cover 2 located below the pre-mixing chamber 201 is fixedly inlaid with a connecting pipe 8, and the inner wall of the connecting pipe 8 is fixedly connected with an intermittent feeder 9, and the dust cover 2 is located below the connecting pipe 8 and is also connected with a rebound feeding pipe 6, and the lower end of the rebound feeding pipe 6 is connected with a conical material spreading pipe 7; Figure 5 , 6As shown, a driving cavity 202 is provided on the inner wall of the middle part of the dust cover 2, and a driving shaft 10 which penetrates to the bottom of the dust cover 2 is rotatably connected at the middle position of the driving cavity 202, and a gear coupling 11 is connected to the lower end of the driving shaft 10 (the specific model is selected according to actual needs and will not be described in detail here), and a cross plug 1101 which is plugged into the column 101 is fixedly connected to the lower end of the gear coupling 11, and a turntable 12 is fixedly sleeved on the side wall of the driving shaft 10 located inside the driving cavity 202, and the turntable 12 includes a diskless disk 1201 and a disk 1202, and the diskless disk 1201 and the disk 1202 each occupy half of the area of ​​the turntable 12, and when the turntable 12 rotates, the disk 1202 intermittently repels the full disk 14, so that the two porous leakage plates can discharge materials intermittently, and the turntable 12 is driven by the column 101 to rotate, without consuming additional energy, and effectively saving costs; Figure 5 , 6 As shown, the dust cover 2 is provided with a piston cavity 203 on the inner wall facing the turntable 12, and the inner wall of the piston cavity 203 is sealingly and slidably connected with the piston 13, and the side wall of the piston 13 is fixedly connected with the full magnetic disk 14 that magnetically repels the turntable 12, and the automatic weighing and batching scale body is used to realize automatic weighing and feeding of auxiliary materials, effectively avoiding the error caused by manual feeding, and the rotation of the column drives the cross plug to rotate, and the cross plug then drives the driving shaft to rotate, and the auxiliary materials are intermittently fed through the magnetic repulsion of the turntable on the full magnetic disk and the hydraulic action, which effectively speeds up the sand mixing efficiency and effectively improves the sand mixing effect; Figure 6 , 7 As shown, the intermittent feeder 9 includes a disk body 901, and a through hole 902 is provided on the middle side wall of the disk body 901, and telescopic movable grooves 903 are provided on the side walls on both sides of the through hole 902, and the inner wall of the telescopic movable groove 903 is sealed and slidably connected with a porous leakage plate 904, two porous leakage plates 904 are distributed up and down, and the leakage ports on the two porous leakage plates 904 are staggered. When the full magnetic disk 14 squeezes the hydraulic oil each time, the two porous leakage plates 904 move toward each other under hydraulic drive, so that the leakage ports will be aligned, and then the auxiliary material will leak out from the leakage port, thereby realizing intermittent uniform feeding; Figure 6 , 8 , 9 and Fig.10It is shown that a plurality of symmetrically distributed elastic pull belts 905 are fixedly connected between the porous leakage plate 904 and the inner wall of the telescopic movable groove 903, and an annular hydraulic cavity 906 connected to the piston cavity 203 is formed on the inner wall of the disk body 901, and the interiors of the piston cavity 203 and the annular hydraulic cavity 906 are simultaneously filled with hydraulic oil, and the rotation of the magnetic disk 1202 is utilized to intermittently repel the full magnetic disk 14, and the full magnetic disk 14 relies on the hydraulic action to make the two porous leakage plates 904 move in an offset manner, so as to realize intermittent and uniform material discharge, which can not only effectively prevent material blockage, but also evenly put the auxiliary materials into the original sand, effectively improving the full mixing effect of the original sand and the auxiliary materials.

[0021] The second implementation method: Fig.11 As shown, the rebound feeding tube 6 includes a plurality of groups of rebounders 15 and a plurality of groups of dispersion cones 16 fixedly connected to the inner wall, and the plurality of groups of rebounders 15 and the plurality of groups of dispersion cones 16 are alternately arranged, and brackets 17 are fixedly connected between the two sides of the dispersion cones 16 and the inner wall of the rebound feeding tube 6. When the auxiliary materials fall into the rebound feeding tube 6, the various auxiliary materials hit the rebounders 15, and the rebounders 15 throw the auxiliary materials upward. In this process, the various auxiliary materials are mixed with each other, thereby effectively improving the premixing effect, and when the auxiliary materials hit the dispersion cones 16, the dispersion cones 16 disperse the various auxiliary materials again, thereby further effectively improving the premixing effect; Fig.11 It is shown that the rebounder 15 includes a rebound plate 1501 (preferably made of plastic material, and other materials can also be selected according to actual needs) rotatably connected to the inner wall of the rebound feeding tube 6, and a flexible membrane 1502 (preferably made of rubber material, and other materials can also be selected according to actual needs) is fixedly connected between the lower end of the rebound plate 1501 and the inner wall of the rebound feeding tube 6, and the space formed by the rebound plate 1501 and the flexible membrane 1502 is filled with an elastic net 1503 (preferably made of rubber material, and other materials can also be selected according to actual needs). When the auxiliary material falls and hits the rebound plate 1501, the elastic force of the elastic net 1503 will cause the rebound plate 1501 to rebound the auxiliary material, and the auxiliary material will be dispersed upward under the rebound action. In this process, a variety of auxiliary materials will be fully mixed, thereby playing an effective pre-mixing role.

[0022] The working principle of this scheme is as follows: first, the raw sand is fed into the high-efficiency grinding wheel sand mixer 1 through the raw sand feeding pipe 3. After the high-efficiency grinding wheel sand mixer 1 is started, the column 101 drives the two grinding wheels to rotate, and the cross plug 1101 is plugged into the top of the column 101. The column 101 drives the cross plug 1101 to rotate, and the cross plug 1101 drives the turntable 12 on the drive shaft 10 to rotate through the gear coupling 11. When the turntable 12 rotates, it drives the magnetic disk 1202 to intermittently repel the full magnetic disk 14. After the full magnetic disk 14 is subjected to the repulsive force, it drives the piston 13 to move and squeeze the hydraulic oil. Under the hydraulic drive, the two porous leakage plates 904 move toward each other. The leakage ports on the two porous leakage plates 904 are up and down in the initial state. The two porous leakage plates 904 are misaligned, and after the two porous leakage plates 904 move, the upper and lower leakage ports are aligned, so that the auxiliary materials can fall downward from the leakage ports, thereby achieving uniform discharge, and the elastic force of the elastic pull belt 905 allows the porous leakage plate 904 to quickly reset, thereby achieving intermittent discharge, and after the auxiliary materials fall into the rebound feeding pipe 6, when the auxiliary materials fall and hit the rebound plate 1501, the elastic force of the elastic net 1503 will cause the rebound plate 1501 to rebound the auxiliary materials, and the auxiliary materials will be dispersed upward under the action of rebound. In this process, various auxiliary materials will be fully mixed, thereby playing an effective pre-mixing role, and when the auxiliary materials hit the dispersion cone 16, the dispersion cone 16 will disperse the various auxiliary materials again, thereby further effectively improving the pre-mixing effect.

[0023] In view of current practical needs, the above-mentioned implementation mode adopted in this application is not limited to the scope of protection. Various changes made within the knowledge scope of technical personnel in this field without departing from the concept of this application still fall within the scope of protection of the present invention.

Claims

1. A method for preparing highly heat-resistant coated sand, characterized in that: The method comprises the following preparation steps: S1. First, heat the raw sand in the raw material bin to increase its temperature, then put the heated raw sand into the roasting furnace for roasting to obtain roasted sand. After roasting, the raw sand is passed through a heat exchanger, and the heat exchanger recovers the heat to heat the raw sand. Then, the roasted sand enters a cooling drum for cooling. The roasted sand after cooling is screened by a circular screen, and the screened roasted sand is transported to the preparation bin by a bucket elevator; S2, the roasted sand in the material preparation bin is put on a belt scale for weighing, and the belt scale transports the roasted sand to a heater for heating. After the heating is completed, the roasted sand is put into a high-efficiency roller sand mixer (1). During the sand mixing process, phenolic resin, urotropine, calcium stearate, zinc borate and other auxiliary materials are added according to the weight ratio. The weight ratio of the above auxiliary materials is: phenolic resin 2%-5%, urotropine 0.1%-2%, calcium stearate 0.1%-2%, zinc borate 2%-8%, and the weight ratio of roasted sand is 100%; S3. After the sand mixing is completed, the coated sand is obtained, which is transported to the swing screen for screening. The screened coated sand is transported to the boiling cooling bed by the vibrating conveyor for cooling. The coated sand left after screening is put into the crushing screen for crushing and screening again, and then transported to the boiling cooling bed. After cooling, the coated sand is transported to the finished product silo to wait for filling.

2. The method for preparing high heat-resistant coated sand according to claim 1, characterized in that: The particle size of the raw sand is 100-200 meshes, and the content of silicon dioxide in the raw sand is 96%-100%.

3. The method for preparing high heat-resistant coated sand according to claim 1, characterized in that: The high-efficiency wheel sand mixer (1) in step S2 comprises a column (101), the upper end of the high-efficiency wheel sand mixer (1) is connected to a dust cover (2), and a raw sand feeding pipe (3) penetrating the dust cover (2) is fixedly connected to one side of the dust cover (2), an auxiliary material bin (4) is fixedly connected to the side of the dust cover (2) away from the raw sand feeding pipe (3), the inner wall of the auxiliary material bin (4) is fixedly connected to a bin partition plate (401), and the bottom of the bin partition plate (401) is fixedly connected to a bin bottom support (402). The partition plate (401) separates the interior of the auxiliary material bin (4) into a plurality of bins, and the bin bottom support (402) is located below each bin and an automatic weighing and batching scale body (5) is installed thereon, the dust cover (2) is located below the auxiliary material bin (4) and an inner wall is provided with a pre-mixing chamber (201), and the plurality of automatic weighing and batching scale bodies (5) are simultaneously connected to the pre-mixing chamber (201) through a feed pipe, and a connecting pipe (8) is fixedly embedded on the inner wall of the dust cover (2) located below the pre-mixing chamber (201), and The inner wall of the connecting pipe (8) is fixedly connected to an intermittent feeder (9); the dust cover (2) is located below the connecting pipe (8) and is also connected to a rebound feeder pipe (6); the lower end of the rebound feeder pipe (6) is connected to a conical material spreading pipe (7); a driving cavity (202) is provided on the inner wall of the middle part of the dust cover (2); a driving shaft (10) penetrating to the lower part of the dust cover (2) is rotatably connected at the middle position of the driving cavity (202); the lower end of the driving shaft (10) is connected to a gear coupling (11). 1), and the lower end of the gear coupling (11) is fixedly connected to a cross plug (1101) plugged into the column (101), the side wall of the drive shaft (10) located inside the drive cavity (202) is fixedly sleeved with a turntable (12), the dust cover (2) is provided with a piston cavity (203) on the inner wall facing the turntable (12), and the inner wall of the piston cavity (203) is sealingly and slidably connected to a piston (13), and the side wall of the piston (13) is fixedly connected to a full magnetic disk (14) that magnetically repels the turntable (12).

4. The method for preparing high heat-resistant coated sand according to claim 3, characterized in that: The intermittent feeder (9) comprises a disc body (901), and a through opening (902) is provided on the middle side wall of the disc body (901), and telescopic movable grooves (903) are provided on both side walls of the through opening (902), and the inner wall of the telescopic movable groove (903) is sealed and slidably connected with a porous leakage plate (904), and a plurality of symmetrically distributed elastic pull bands (905) are fixedly connected between the porous leakage plate (904) and the inner wall of the telescopic movable groove (903), and an annular hydraulic cavity (906) connected to the piston cavity (203) is provided on the inner wall of the disc body (901), and the interiors of the piston cavity (203) and the annular hydraulic cavity (906) are simultaneously filled with hydraulic oil.

5. The method for preparing high heat-resistant coated sand according to claim 4, characterized in that: The two porous leakage plates (904) are distributed up and down, and the leakage openings on the two porous leakage plates (904) are staggered.

6. The method for preparing high heat-resistant coated sand according to claim 3, characterized in that: The turntable (12) comprises a portion without a magnetic disk (1201) and a portion with a magnetic disk (1202), and the portion without a magnetic disk (1201) and the portion with a magnetic disk (1202) each occupy half of the area of ​​the turntable (12).

7. The method for preparing high heat-resistant coated sand according to claim 3, characterized in that: The rebound-type feeding pipe (6) comprises a plurality of groups of rebounders (15) and a plurality of groups of dispersion cones (16) fixedly connected to the inner wall, and the plurality of groups of rebounders (15) and the plurality of groups of dispersion cones (16) are arranged alternately, and a bracket (17) is fixedly connected between the two sides of the dispersion cone (16) and the inner wall of the rebound-type feeding pipe (6).

8. The method for preparing high heat-resistant coated sand according to claim 7, characterized in that: The rebounder (15) comprises a rebound plate (1501) rotatably connected to the inner wall of the rebound feeding tube (6), and a flexible membrane (1502) is fixedly connected between the lower end of the rebound plate (1501) and the inner wall of the rebound feeding tube (6), and the space formed by the rebound plate (1501) and the flexible membrane (1502) is filled with an elastic net (1503).

Images