Roasting sand drying section waste heat recycling system

Abstract

The invention belongs to the technical field of quartz sand screening processes and equipment, and particularly relates to a roasting sand drying section waste heat recycling system. A multi-section process in a conventional roasted sand production process relates to operations such as high-temperature roasting and drying, a high-temperature heat source needs to be provided, a large amount of waste heat energy exists after the treatment process, tail gas is discharged after necessary treatments such as dust removal and purification under conventional conditions, and heat loss is serious. The invention provides a roasting sand drying section waste heat recycling system, and aims to solve the problem of recycling of high-temperature waste heat after a heat source is subjected to various treatment links. The waste heat recycling system adopts a relatively independent waste heat recycling circulating system, so that the cooling requirement of product sand is fully utilized, and waste heat is utilized; the material distribution bin and the preheating bin which are relatively simple in structure are adopted, so that gas-solid two-phase materials are fully mixed in the upper cavity for heat exchange, and sand is prevented from entering the lower cavity as far as possible.

Description

Technical Field

[0001] This invention belongs to the technical field of quartz sand screening process and equipment, specifically relating to a waste heat recovery and reuse system for the drying section of roasted sand. Background Technology

[0002] Quartz sand is an important industrial mineral raw material, widely used in numerous industries such as glass, electronics, machinery casting, metallurgy, chemicals, cement, daily-use ceramics, refractory materials, superhard materials, functional fillers, and oil drilling. Silica sand classification primarily employs screening and hydraulic classification. Hydraulic classification of silica sand is currently the main screening method, and its production line includes steps such as raw sand collection, transportation, primary desliming and impurity removal, scrubbing, classification, and concentration. This production line generally operates continuously. Calcinated sand refers to silica sand that has undergone high-temperature calcination treatment. Its main component is silicon dioxide (SiO2), a common industrial raw material and casting material. The main characteristics of calcined sand production are: high-temperature calcination treatment above 900°C to remove organic matter, moisture, and volatiles; high silica content (usually ≥98%), stable composition, and few impurities; performance optimization through high-temperature calcination, reducing gas generation and minimizing defects caused by gas during casting; improved refractoriness and enhanced high-temperature resistance; and improved fluidity, making sand molds easier to form. Calcined sand is mainly used in the foundry industry, refractory materials in the building materials industry, ceramic glazes, chemical silicate raw materials, and metal smelting auxiliaries. A typical production line process for calcined sand generally includes: mineral processing (selecting high-purity silica sand, usually obtained through water washing and separation, as the raw material for the calcined sand drying process), drying (reducing the moisture content of the refined sand to below 0.5% in a dry, loose state), calcination (high-temperature calcination in a rotary kiln or vertical furnace), cooling and screening (controlling particle size distribution), and packaging. Through high-temperature purification and performance optimization, calcined sand has become an ideal choice for high-end foundry and refractory materials; its stability and low gas evolution characteristics are particularly suitable for the production of precision castings.

[0003] In the above-mentioned calcined sand production process, there are multiple processes involving high-temperature calcination, drying and other operations, which require the provision of high-temperature heat sources. After the processing, there is a large amount of residual heat energy, which is normally discharged as exhaust gas after necessary treatment such as dust removal and purification, resulting in serious heat loss. Summary of the Invention

[0004] The purpose of this invention is to solve the above-mentioned existing problems and provide a waste heat recovery and reuse system for the drying section of roasted sand, which aims to solve the problem of recovering and reusing the waste heat that still has a high temperature after the heat source has gone through various processing stages.

[0005] The above objective is achieved by the following technical solution: A waste heat recovery and reuse system for the drying section of calcined sand production line is installed in the drying section of the calcined sand production line, which includes a burner, a rotary kiln, and a material distribution silo. The burner is used to provide a heat source to the rotary kiln and is equipped with a gas supply pipeline. The rotary kiln is a low-speed rotating, slightly inclined steel cylinder. The material is added from the kiln tail at the high end of the cylinder and moves axially towards the kiln head at the low end under the action of the cylinder rotation and gravity. The distribution bin is used to receive the material conveyed from the rotary kiln and realize gas-solid separation. Among them, the gaseous hot gas is conveyed to the waste heat recovery and reuse system, and the solid sand is output to other subsequent processes or as a product. Its features are: The waste heat recovery and reuse system includes a cyclone separator, a preheating chamber, a feeding section, and a lifting section; The cyclone separator is used to remove dust from the gaseous hot air conveyed from the distribution bin and to convey the dust-removed hot air to the preheating bin. The cyclone separator includes a separator body, an air inlet, an air outlet, and a discharge port. The distribution bin is connected to the air inlet of the cyclone separator through a pipe, the air outlet is connected to the preheating bin through a pipe, and the discharge port is used to discharge solid dust. The preheating chamber is used to preheat the raw materials from the feeding section using the hot air delivered by the cyclone separator, so that the preheated materials can be provided to the rotary kiln via the feeding section, thereby realizing the recovery and reuse of waste heat in the drying section of the roasted sand production line. The feeding section is used to supply raw materials to the waste heat recovery and reuse system; The material lifting section is used to lift and convey materials preheated in the preheating chamber to the rotary kiln.

[0006] The rotary kiln includes a kiln inlet and a kiln outlet.

[0007] The material distribution hopper includes a material distribution shell, a hot sand inlet, a cold sand outlet, a cold air device, a hot air outlet, and a cooling plate; The material distribution shell is a hollow square, round, or irregular shape. The cooling plate is placed horizontally or inclined in the middle or lower middle part of the material distribution shell. The cooling plate divides the material distribution shell into a hot sand chamber and a cold air chamber. The cooling plate is flat and has numerous through holes for cold air to pass through; The hot sand inlet is flexibly connected to the kiln outlet of the rotary kiln and is located on the distribution shell of the hot sand chamber of the distribution bin; The cold sand outlet is located at the end of the hot sand chamber of the distribution bin, away from the hot sand inlet, and is situated on the distribution shell of the hot sand chamber of the distribution bin. The cooling system includes a cooler and a cooling duct. The cooler is connected to the material distribution bin via the cooling duct, and the cooling duct is flexibly connected to the cooling chamber of the material distribution bin. The hot air outlet is located at the top of the distribution shell of the hot sand chamber of the distribution bin, and is far away from the hot sand inlet of the hot sand chamber.

[0008] The material distribution bin is equipped with a first vibration device, which is an exciter or a vibration motor.

[0009] The feeding unit includes a conveyor belt and a hopper. External machinery transports raw materials to the hopper, and the conveyor belt lifts and transports the raw materials in the hopper to the preheating chamber.

[0010] The material feeding section includes an elevator, a receiving hopper, and a dumping hopper. The receiving hopper is used to transfer the preheated material from the preheating chamber to the elevator, the elevator is used to lift and convey the material, and the dumping hopper is used to convey the material from the elevator to the rotary kiln.

[0011] The preheating chamber includes a preheating shell, which is a hollow square, round or irregular shape. The preheating shell is divided into an upper cover and a heat exchange section. The upper cover and the heat exchange section are fastened together, and the fastening part is connected by a flexible material. The upper cover is in a stationary state. The heat exchange section is equipped with a second vibration device, which is a vibrator or a vibration motor. The top of the upper cover is provided with a raw sand inlet, which is used to receive the raw materials conveyed by the conveyor belt into the preheating chamber; The heat exchange section is equipped with a heat exchange plate, which is placed horizontally or inclined in the middle or lower middle part of the heat exchange section. The heat exchange plate divides the preheating chamber into a heat exchange cavity and a hot air cavity. The heat exchange plate is flat and has numerous through holes for hot air to pass through. The preheating shell of the heat exchange section is provided with a preheating material inlet and a heat exchange air outlet. The preheating material inlet is located above the heat exchange plate, and the heat exchange air outlet is located below the heat exchange plate and is arranged opposite to the preheating material inlet.

[0012] The waste heat recovery and reuse system is equipped with an auxiliary purification module, which is used to remove water vapor generated at the kiln head of the rotary kiln, as well as trace amounts of other gaseous components that may be present, to avoid adding unnecessary moisture to the raw materials.

[0013] The auxiliary purification module includes a condensation section and a purification section. The condensation section is located at the kiln head of the rotary kiln and is connected to the kiln head through a vertical pipe. The condenser section is horizontally tubular with a circular or square cross-section. The bottom surface of the tubular condenser section has multiple openings. The condenser section is used to condense part of the water vapor in the gaseous mixture discharged from the rotary kiln into liquid, and at the same time, it partially adsorbs dust. The liquid water and dust mix to form sludge, which can be discharged through the openings at the bottom of the condenser section. The purification section is located at the end of the condensation section, and the purification section is connected to the condensation section through a pipeline; the purification section is used to purify the gaseous mixture transported by the condensation section so that it meets the emission standards.

[0014] The beneficial effects of this invention are as follows: (1) A relatively independent waste heat recovery and utilization circulation system is adopted. Under the condition of minimal or no impact on the working efficiency of the drying production line, the waste heat is utilized to make full use of the cooling needs of the product sand in the process, thus greatly avoiding heat loss and waste. (2) Set up an auxiliary purification module that operates independently of the waste heat recovery and reuse system to treat and discharge the gaseous mixture generated in the rotary kiln separately, so as to avoid harmful gases, water vapor and other substances from entering the waste heat recovery and reuse system as much as possible. (3) Adopting a relatively simple structure of the material distribution bin and preheating bin, so that the gas-solid two-phase materials are fully mixed and heat exchanged in the upper chamber, and the sand material is avoided from entering the lower chamber as much as possible. Attached Figure Description

[0015] The following describes the accompanying drawings in this application: Figure 1 This is a schematic diagram of the overall structure of the calcined sand drying section and the remaining heat recovery and reuse system in Embodiment 1 of this application; Figure 2 This is a partial cross-sectional view of the material distribution bin in Embodiment 1 of this application; Figure 3 This is a longitudinal cross-sectional view of the preheating chamber in Embodiment 2 of this application.

[0016] The accompanying figure is labeled as follows: 1. Burner; 11. Gas supply pipelines; 2. Rotary kiln, 21. Kiln body, 22. Kiln tail, 23. Kiln head, 24. Kiln feed inlet, 25. Kiln discharge outlet; 3. Material hopper, 31. Cold air device, 311. Cold air blower, 312. Cold air duct, 32. Material distribution shell, 321. Hot sand chamber, 322. Cold air chamber, 33. Hot sand inlet, 34. Cold sand outlet, 35. Hot air outlet, 36. Cooling plate, 37. First vibration device; 4 Cyclone separator, 41 Separator body, 42 Air inlet, 43 Air outlet, 44 Discharge port; 5 Preheating chamber, 51 Preheating shell, 52 Upper cover, 521 Raw sand inlet, 53 Heat exchange section, 531 Preheating material inlet, 532 Heat exchange air outlet, 533 Heat exchange plate, 534 Heat exchange cavity, 535 Hot air cavity, 54 Second vibration device; 6. Feeding section; 61. Conveyor belt; 62. Collection hopper; 7. Material lifting section; 71. Elevator; 72. Receiving hopper; 73. Discharge hopper; 8. Auxiliary purification module, 81. Condensation section, 82. Purification section. Detailed Implementation

[0017] Example 1.

[0018] like Figure 1-3As shown in this embodiment, the waste heat recovery and reuse system for the calcined sand drying section is installed in the drying section of the calcined sand production line. The calcined sand production line includes a burner 1, a rotary kiln 2, and a distribution bin 3. The burner 1 is used to provide a heat source to the rotary kiln 2, and the burner 1 is equipped with a gas supply pipe 11. The rotary kiln 2 is a low-speed rotating, slightly inclined steel cylinder 21. The material is added from the kiln tail 22 at the high end of the cylinder 21. Under the action of rotation of the cylinder 21 and gravity, the material moves axially towards the kiln head 23 at the low end. The distribution bin 3 is used to receive the material conveyed from the rotary kiln 2 and realize gas-solid separation, wherein: the gaseous hot gas is conveyed to the waste heat recovery and reuse system, and the solid sand is output to other subsequent processes or as a product. Taking roasted sand as an example, the burner 1 can provide a high temperature of about 1000℃ or above to dry the wet sand with a moisture content of about 2-8% in the rotary kiln 2. At the kiln head 23 outlet of the rotary kiln 2, the moisture content of the sand can be reduced to below 1%. At the same time, the sand itself has a certain temperature. On the one hand, it is necessary to cool the sand for subsequent processing. On the other hand, this part of the heat can be recovered and reused. In this embodiment, the heat is recovered and used to preheat the wet sand of the raw material to achieve the purpose of reuse.

[0019] The aforementioned reuse of sand heat is achieved through a waste heat recovery and reuse system, which includes a cyclone separator 4, a preheating chamber 5, a feeding section 6, and a lifting section 7. The cyclone separator 4 is used to remove dust from the gaseous hot air transported from the distribution chamber 3 and to transport the dust-removed hot air to the preheating chamber 5. The cyclone separator 4 includes a separator body 41, an air inlet 42, an air outlet 43, and a discharge port 44. The distribution chamber 3 is connected to the air inlet 42 of the cyclone separator 4 through a pipe, the air outlet 43 is connected to the preheating chamber 5 through a pipe, and the discharge port 44 is used to discharge the solid dust separated from the recovered hot air to avoid introducing unnecessary impurities into the original material.

[0020] The preheating chamber 5 is used to preheat the raw materials conveyed by the feeding section 6 with the hot air delivered by the cyclone separator 4, so that the preheated materials can be provided to the rotary kiln 2 via the lifting section 7, thereby realizing the recovery and reuse of waste heat in the drying section of the calcined sand production line. The feeding section 6 supplies raw materials to the waste heat recovery and reuse system. Taking calcined sand as an example, the moisture content of the wet sand is generally 2-8%, which may vary due to seasonal climate and other reasons. However, this difference does not affect the waste heat recovery and reuse effect described in this embodiment. The lifting section 7 lifts the material preheated by the preheating chamber and conveys it to the rotary kiln 2. The lifting section 7 and the feeding section 6 are used for material transfer, and any existing technical solution can be used to achieve the above functions.

[0021] The rotary kiln 2 includes a kiln inlet 24 and a kiln outlet 25.

[0022] The material distribution chamber 3 includes a material distribution shell 32, a hot sand inlet 33, a cold sand outlet 34, a cold air device 31, a hot air outlet 35, and a cooling plate 36. The material distribution shell 32 is a hollow square, round, or irregular shape. The cooling plate 36 is placed horizontally or inclined in the middle or lower middle part of the material distribution shell 32. The cooling plate 36 divides the material distribution shell into a hot sand chamber 321 and a cold air chamber 322. The cooling plate 36 is flat and has densely packed through holes for cold air to pass through. The hot sand chamber 321 is connected to the rotary kiln 2 via the hot sand inlet 33 and the kiln outlet 25, allowing the dried sand in the rotary kiln 2 to enter the hot sand chamber 321, which is also the heat source for waste heat recovery and reuse as described in this embodiment. The hot sand chamber 321 and the cold air chamber 322 are separated by a cooling plate 36. The cold air chamber 322 is supplied with air pressure by a cold air device 31. The cold air lifts the hot sand through the through holes of the cooling plate 36 to prevent the sand from leaking down the cooling plate. At the same time, the cold air and the hot sand exchange heat, cooling the hot sand and recovering waste heat. The cooled sand is output through the cold sand outlet 34 under the action of wind, and the heated cold air enters the cyclone separator 4 through the hot air outlet 35.

[0023] The hot sand inlet 33 is flexibly connected to the kiln outlet 25 of the rotary kiln 2 and is located on the distribution shell of the hot sand chamber 321 of the distribution bin 3; the cold sand outlet 34 is located at the end of the hot sand chamber 321 of the distribution bin 3 away from the hot sand inlet 33 and is located on the distribution shell of the hot sand chamber 321 of the distribution bin 3. Based on the above description, the upward airflow generated by the air pressure of the cold air chamber 322 in the distribution bin 3 allows the cold air to contact the hot sand in the hot sand chamber 321 to achieve heat exchange. Therefore, the cold air chamber 322 and the hot sand chamber 321 should be kept as closed as possible. However, the connection between each inlet and outlet may not be completely sealed. For example, the flexible connection between the hot sand inlet 33 and the kiln outlet 25 is set for this reason, which does not affect the realization of the overall heat exchange function. In addition, the material distribution bin 3 can also be equipped with a vibration device to increase the speed of sand transfer and improve heat exchange efficiency. Therefore, at least the cold air pipe 312 and the cold air chamber 322 of the rotary kiln 2 should also be flexibly connected according to the above principle.

[0024] The cooling air device 31 includes a cooling fan 311 and a cooling air duct 312. The cooling fan 311 is connected to the material distribution bin 3 through the cooling air duct 312, and the cooling air duct 312 is flexibly connected to the cooling air chamber 322 of the material distribution bin 3. The hot air outlet 35 is located at the top of the material distribution shell 32 of the hot sand chamber 321 of the material distribution bin 3, and is far away from the hot sand inlet 33 of the hot sand chamber 321 of the material distribution bin 3.

[0025] Example 2.

[0026] like Figure 2As shown, based on the above embodiments, the material distribution bin 3 in this embodiment is equipped with a first vibration device 37. The first vibration device 37 can be implemented using a vibrator or a vibration motor, either of which can be achieved using any existing technology, and will not be described in detail here. The first vibration device 37 causes the entire material distribution bin 3 to vibrate, which helps to discharge sand.

[0027] Furthermore, the feeding unit 6 includes a conveyor belt 61 and a collection hopper 62. External machinery, such as a forklift, transports raw materials to the collection hopper 62. The collection hopper 62 can be an inverted pyramidal or inverted conical bucket-shaped container, with its upper opening receiving the materials delivered by the external machinery and its lower opening corresponding to the conveyor belt 61. The conveyor belt 61 lifts and transports the raw materials in the collection hopper 62 to the preheating chamber 5.

[0028] Furthermore, the material lifting unit 7 includes an elevator 71, a receiving hopper 72, and a discharging hopper 73. The receiving hopper 72 is used to transfer the preheated material from the preheating chamber 5 to the elevator 71. The elevator 71 is used to lift and convey the material. The discharging hopper 73 is used to convey the material from the elevator 71 to the rotary kiln 2. The elevator 71 can be implemented using any existing technology, and will not be described in detail here.

[0029] like Figure 3 As shown, the preheating chamber 5 further includes a preheating shell 51, which is a hollow square, round or irregular shape. The preheating shell 51 is divided into an upper cover 52 and a heat exchange part 53. The upper cover 52 and the heat exchange part 53 are fastened together, and the fastening part is connected by a flexible material. The upper cover 52 is in a stationary state. The heat exchange part 53 is provided with a second vibration device 54. The second vibration device 54 is a vibrator or a vibration motor, which can be implemented by any existing technology, and will not be described in detail.

[0030] The top of the upper cover 52 is provided with a raw sand inlet 521, which is used to receive the raw material conveyed by the conveyor belt 61 into the preheating chamber 5. The heat exchange section 53 is provided with a heat exchange plate 533, which is placed horizontally or inclined in the middle or lower middle part of the heat exchange section 53. The heat exchange plate 533 divides the preheating chamber 5 into a heat exchange chamber 534 and a hot air chamber 535. The heat exchange plate 533 is flat and has densely distributed through holes for hot air to pass through. The preheating shell 51 of the heat exchange section 53 is provided with a preheating material inlet 531 and a heat exchange air outlet 532. The preheating material inlet 531 is located above the heat exchange plate 533, and the heat exchange air outlet 532 is located below the heat exchange plate 533 and is arranged opposite to the preheating material inlet 531.

[0031] Similar to the structure of the distribution bin 3, the preheating bin 5 is divided into two chambers by a heat exchange plate 533. The lower chamber is a hot air chamber 535 that receives hot air from the distribution bin 3. The hot air creates upward internal pressure to blow the wet sand in the heat exchange chamber 534. The upper part of the heat exchange plate 533 is the heat exchange chamber 534. The shell of the heat exchange chamber 534 is composed of an upper cover 52, part of the hot air chamber 535, and the heat exchange plate 533. The wet sand enters the heat exchange chamber 534 through the raw sand inlet 521. Under the hot air flow, the wet sand rolls and exchanges heat freely in the heat exchange chamber 534, realizing the use of residual heat to preheat the raw wet sand. The preheated sand is discharged to the lifting part 7 through the preheating material inlet 531.

[0032] Furthermore, the heat exchange section 53 is equipped with a second vibration device 54. Therefore, similar to the above embodiment, the components connected to the heat exchange section 53 should also adopt vibration-damping flexible connections as needed. For example, since the upper cover 52 and the heat exchange section 53 are locked together, a flexible material is used for the movable connection. For example, the joint is made of flexible or elastic materials such as cloth or rubber to reduce hot air leakage and reduce heat exchange efficiency.

[0033] Example 3.

[0034] like Figure 1 As shown, based on the above embodiments, the waste heat recovery and reuse system in this embodiment is equipped with an auxiliary purification module 8. This auxiliary purification module 8 is used to remove water vapor generated at the kiln head 23 of the rotary kiln 2, as well as trace amounts of other gaseous components, to avoid adding unnecessary moisture to the raw materials. The auxiliary purification module 8 includes a condenser section 81 and a purification section 82. The condenser section 81 is located at the kiln head 23 of the rotary kiln 2 and is connected to the kiln head 23 through a vertical pipe. The condenser section 81 is horizontally tubular with a circular or square cross-section, and has multiple openings on its bottom surface. The condenser section 81 is used to condense some of the water vapor in the gaseous mixture discharged from the rotary kiln 2 into liquid, while also partially adsorbing dust. The liquid water and dust mix to form sludge, which can be discharged through the openings at the bottom of the condenser section. The purification section 82 is located at the end of the condenser section 81 and is connected to the condenser section 81 through a pipe. The purification section 82 is used to purify the gaseous mixture transported by the condenser section 81 to meet emission standards. The purification section can be implemented using any existing and known technology, which will not be elaborated further.

[0035] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A waste heat recovery and reuse system for the drying section of calcined sand production line. The waste heat recovery and reuse system is installed in the drying section of the calcined sand production line, which includes a burner, a rotary kiln, and a material distribution silo. The burner is used to provide a heat source for the rotary kiln, and the burner is equipped with a gas supply pipeline; A rotary kiln is a steel cylinder that can rotate and is set at an inclination. The material is fed from the kiln tail at the high end of the cylinder, and moves axially towards the kiln head at the low end under the action of the cylinder rotation and gravity. The material distribution bin is used to receive materials conveyed from the rotary kiln and to achieve gas-solid separation, wherein: Gaseous hot gas is transported to a waste heat recovery and reuse system, while solid sand is output to other subsequent processes or as a product. Its features are: The waste heat recovery and reuse system includes a cyclone separator, a preheating chamber, a feeding section, and a lifting section; Cyclone separators are used to remove dust from the gaseous hot air conveyed from the distribution bin and then convey the dust-removed hot air to the preheating bin. The cyclone separator includes a separator body, an air inlet, an air outlet, and a discharge port. The distribution bin is connected to the air inlet of the cyclone separator through a pipe, the air outlet is connected to the preheating bin through a pipe, and the discharge port is used to discharge solid dust. The preheating chamber is used to preheat the raw materials delivered from the feeding section using hot air from the cyclone separator, so that the preheated materials can be provided to the rotary kiln via the lifting section. The feeding section is used to supply raw materials to the waste heat recovery and reuse system; The material lifting section is used to lift and convey materials preheated in the preheating chamber to the rotary kiln.

2. The waste heat recovery and reuse system for the calcined sand drying section according to claim 1, characterized in that: The rotary kiln includes a kiln inlet and a kiln outlet.

3. The waste heat recovery and reuse system for the calcined sand drying section according to claim 1, characterized in that: The material distribution hopper includes a material distribution shell, a hot sand inlet, a cold sand outlet, a cold air device, a hot air outlet, and a cooling plate; The material distribution shell is a hollow square, round, or irregular shape. The cooling plate is placed horizontally or inclined in the middle or lower middle part of the material distribution shell. The cooling plate divides the material distribution shell into a hot sand chamber and a cold air chamber. The cooling plate is flat and has numerous through holes for cold air to pass through; The hot sand inlet is flexibly connected to the kiln outlet of the rotary kiln and is located on the distribution shell of the hot sand chamber of the distribution bin; The cold sand outlet is located at the end of the hot sand chamber of the distribution bin, away from the hot sand inlet, and is situated on the distribution shell of the hot sand chamber of the distribution bin. The cooling system includes a cooler and a cooling duct. The cooler is connected to the material distribution bin via the cooling duct, and the cooling duct is flexibly connected to the cooling chamber of the material distribution bin. The hot air outlet is located at the top of the distribution shell of the hot sand chamber of the distribution bin, and is far away from the hot sand inlet of the hot sand chamber.

4. The waste heat recovery and reuse system for the calcined sand drying section according to any one of claims 1 to 3, characterized in that: The material distribution bin is equipped with a first vibration device, which is an exciter or a vibration motor.

5. The waste heat recovery and reuse system for the calcined sand drying section according to claim 1, characterized in that: The feeding unit includes a conveyor belt and a hopper. External machinery transports raw materials to the hopper, and the conveyor belt lifts and transports the raw materials in the hopper to the preheating chamber.

6. The waste heat recovery and reuse system for the calcined sand drying section according to claim 1, characterized in that: The material feeding section includes an elevator, a receiving hopper, and a dumping hopper. The receiving hopper is used to transfer the preheated material from the preheating chamber to the elevator, the elevator is used to lift and convey the material, and the dumping hopper is used to convey the material from the elevator to the rotary kiln.

7. The waste heat recovery and reuse system for the calcined sand drying section according to any one of claims 1 to 3, 5, and 6, characterized in that: The preheating chamber includes a preheating shell, which is a hollow square, round or irregular shape. The preheating shell is divided into an upper cover and a heat exchange section. The upper cover and the heat exchange section are fastened together, and the fastening part is connected by a flexible material. The upper cover is in a stationary state. The heat exchange section is equipped with a second vibration device, which is a vibrator or a vibration motor. The top of the upper cover is provided with a raw sand inlet, which is used to receive the raw materials conveyed by the conveyor belt into the preheating chamber; The heat exchange section is equipped with a heat exchange plate, which is placed horizontally or inclined in the middle or lower middle part of the heat exchange section. The heat exchange plate divides the preheating chamber into a heat exchange cavity and a hot air cavity. The heat exchange plate is flat and has numerous through holes for hot air to pass through. The preheating shell of the heat exchange section is provided with a preheating material inlet and a heat exchange air outlet. The preheating material inlet is located above the heat exchange plate, and the heat exchange air outlet is located below the heat exchange plate and is arranged opposite to the preheating material inlet.

8. The waste heat recovery and reuse system for the calcined sand drying section according to claim 7, characterized in that: The waste heat recovery and reuse system is equipped with an auxiliary purification module, which is used to remove water vapor generated at the kiln head of the rotary kiln.

9. The waste heat recovery and reuse system for the calcined sand drying section according to claim 8, characterized in that: The auxiliary purification module includes a condensation section and a purification section. The condensation section is located at the kiln head of the rotary kiln and is connected to the kiln head through a vertical pipe. The condenser section is horizontally tubular with a circular or square cross-section, and the bottom surface of the tubular condenser section has multiple openings; The purification section is located at the end of the condensation section, and the purification section and the condensation section are connected by a pipe.

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