Precoated sand roasting regeneration treatment method and device

Abstract

The invention discloses a foundry sand roasting regeneration treatment method and device, in particular to precoated sand, the foundry sand roasting regeneration treatment device comprises a used sand hopper, a heat exchange device, a high-temperature curing bin, a roasting furnace, a first screw feeder, a first preheating sand hopper, an elevator, a second preheating sand hopper, a second screw feeder and a regenerated sand bin, and the heat exchange device comprises an outer barrel and an inner barrel; the feeding side of the inner barrel body is connected with the discharging end of a high-temperature curing stock bin, the discharging side of the inner barrel body is connected with the feeding end of a regenerated sand stock bin, the feeding side of the outer barrel body is connected with the discharging end of a used sand hopper, and the discharging side of the outer barrel body is connected with the feeding end of a second preheating sand hopper. And the rotary inner cylinder body enables the roasted high-temperature sand to be cooled and the used sand to be preheated synchronously, so that the maximum utilization of heat energy is realized.

Description

Technical Field

[0001] The invention relates to the technical field of regenerated sand, in particular to the technical field of a method and device for roasting and regenerating coated sand. Background Art

[0002] Recycled sand is the old sand that has been processed in the casting production and basically restored its usability and can be reused; during sand casting, 1 to 3 tons of used sand will be generated for every ton of castings produced; there are basically two ways to utilize old sand, namely, recycling old sand and recycling old sand after regeneration; after the casting mold is poured, if most of the binder in the molding sand has not undergone irreversible changes, the original properties of the molding sand can be restored by removing impurities, cooling after ash absorption and remixing, and this treatment method is called recycling of old sand; recycling of recycled sand is to regenerate the used old sand appropriately so that it can achieve the usability of original casting sand and replace new sand for casting production.

[0003] For coated sand shell casting, about 1 ton of new sand is consumed for every ton of castings produced. If no regeneration is performed, it means that about 1 ton of sand is consumed for every ton of castings produced, resulting in increased production costs and a large amount of waste of sand resources. If the coated sand is not recycled and used directly, it will cause harm: (1) Increased gas emission of the molding sand: When the old sand is not recycled and directly reused, the gas emission of the molding sand will increase significantly with the continuous addition of organic binders; high gas emission will cause casting defects such as pores to easily form during the solidification process of the casting, thereby affecting the quality of the casting. and performance; (2) Reduce the degree of adhesion between sand particles and new binder film: the resin film remaining on the surface of old sand will form an intermediate layer when the sand is mixed again, which will hinder the close bonding between the sand particles and the newly formed binder film, resulting in a significant reduction in the shell mold strength, making the mold easy to break or deform during the pouring process; (3) Weaken the strength of the mold: for thermosetting resin sand (such as shell sand), after one heating and curing, the resin film will lose some or all of its activity; if heated again, the resin film will produce a carbonization phenomenon, causing it to lose strength, resulting in a decrease in the overall strength of the mold.

[0004] Thermal regeneration is to heat the old sand to a certain temperature and maintain it for a certain period of time to remove the binder film on the surface of the old sand. For organic binder sand such as coated sand, the thermal regeneration effect is more obvious and a large amount of organic matter can be burned and removed.

[0005] The roasting thermal regeneration system commonly used now has many problems, such as: (1) The old sand is transported over a long distance: In the regenerated sand production line, the old sand is transported to the bucket of the bucket elevator via a belt conveyor and then lifted to the roasting furnace. After roasting, it is transported over a long distance during the cooling process to fully cool the regenerated sand. (2) The roasting furnace is divided into two upper and lower chambers. The upper chamber is the old sand roasting chamber, and the lower chamber is the combustion chamber. In the upper roasting chamber, the sand is heated in a fluidized manner and transported to the sand outlet. There are problems such as low old sand roasting efficiency and a large amount of hot sand accumulated in the roasting chamber. (3) The heating of the old sand is completely dependent on the roasting furnace. , the heat of the high-temperature sand after roasting is not utilized, and even in the cooling process, additional energy consumption and resources such as blowers and water cooling are added to ensure the cooling efficiency of the high-temperature sand, which greatly reduces production efficiency and causes energy waste; (4) In some regenerated sand production lines that have added heat exchange devices, there are problems such as low efficiency, poor effect, and insufficient thermal energy utilization of the heat exchange devices. For example, when a blower is used to blow the heat of the high-temperature sand through a pipe to the roasting furnace, there will be some loss during the heat transfer process, and the heat from cooling the high-temperature sand is not fully utilized. Summary of the invention

[0006] The purpose of the present invention is to solve the problems in the prior art and to provide a method and device for roasting and regenerating coated sand, which can solve the above problems.

[0007] To achieve the above-mentioned purpose, the present invention proposes a coated sand roasting and regeneration processing device, comprising an old sand hopper, a heat exchange device, a high-temperature aging silo, a roasting furnace, a first screw feeder, a first preheating sand hopper, an elevator, a second preheating sand hopper, a second screw feeder and a regenerated sand silo, the heat exchange device comprises an outer cylinder and an inner cylinder, the feed side of the inner cylinder is connected to the discharge end of the high-temperature aging silo, the discharge side of the inner cylinder is connected to the feed end of the regenerated sand silo, the feed side of the outer cylinder is connected to the old sand silo The discharge end of the outer cylinder is connected to the feed end of the second preheating sand hopper, the discharge end of the second preheating sand hopper is connected to the feed end of the elevator, the discharge end of the elevator is connected to the feed end of the second screw feeder, the discharge end of the second screw feeder is connected to the feed end of the first preheating sand hopper, the discharge end of the first preheating sand hopper is connected to the feed end of the roasting furnace, and the discharge end of the roasting furnace is connected to the feed end of the high-temperature aging silo.

[0008] Preferably, the outer cylinder and the inner cylinder are an integral rotatable structure, a preheating space for preheating old sand is provided between the outer cylinder and the inner cylinder, a space for cooling hot sand is provided inside the inner cylinder, an inner spiral conveying mechanism is provided on the inner wall of the inner cylinder, the inner spiral conveying mechanism is a spiral protrusion or a spiral groove, an outer spiral blade is provided on the outer wall of the inner cylinder, the spiral directions of the outer spiral blade and the inner spiral conveying mechanism are opposite, the inner cylinder or the outer cylinder is connected to a driving mechanism, and the driving mechanism drives the inner and outer cylinders to rotate.

[0009] Preferably, the driving mechanism includes a bracket and a driving motor, the two ends of the inner cylinder are arranged through the two ends of the outer cylinder, a bracket is provided under the inner cylinder, the part of the inner cylinder protruding from the outer cylinder is rotatably mounted on the bracket, and a rotating gear is provided on the inner cylinder, the rotating gear is meshed with a driving gear, and the driving gear is connected to the driving motor.

[0010] Preferably, a feed cover is rotatably mounted on the feed end of the inner cylinder, a hot sand inlet is provided on the feed cover, and the hot sand inlet is connected to the high-temperature aging silo through a feed hopper; a discharge cover is rotatably mounted on the discharge end of the inner cylinder, a hot sand outlet is provided on the discharge cover, and the hot sand outlet is connected to the regenerated sand silo through a discharge hopper; the discharge end of the inner cylinder is located on one side of the feed end of the outer cylinder; the feed end of the inner cylinder is located on one side of the discharge end of the outer cylinder.

[0011] Preferably, both the inner wall and the outer wall of the inner cylinder are provided with raised heat exchange structures.

[0012] Preferably, the roasting furnace comprises a heating furnace and a rotating furnace core, a rotating furnace core is rotatably installed inside the heating furnace, the rotating furnace core is rotated by a rotating motor, two ends of the rotating furnace core are arranged through two ends of the heating furnace, a spiral conveying groove is arranged on the inner wall of the rotating furnace core, a roasting chamber is arranged inside the rotating furnace core, a plurality of heat-conducting protrusions are arranged on the inner wall of the rotating furnace core, reinforcing ribs are convexly arranged on the outer wall of the rotating furnace core, and the heating furnace comprises an upper furnace body and a lower furnace body, and the upper furnace body and the lower furnace body are respectively arranged on the upper and lower sides of the rotating furnace core.

[0013] Preferably, the heating furnace is a resistance heating furnace, and heating resistance wires are provided in the upper furnace body and the lower furnace body.

[0014] Preferably, the heating furnace is composed of a lower furnace body and an upper cover, wherein the lower furnace body performs the heating function and the upper cover adopts a heat preservation structure design. Preferably, the rotating furnace core is provided with a feed hopper at one end of which a feed baffle is rotatably installed, a feed hole connected to the roasting chamber is formed on the feed baffle, the feed hole is connected to the discharge end of the first screw feeder, the feed hopper is connected to the feeding device, the rotating furnace core is provided with a discharge hopper at one end of which a discharge baffle is rotatably installed, a discharge hole connected to the roasting chamber is formed on the discharge baffle, and the discharge hole is connected to the feed end of the high-temperature aging silo.

[0015] The present application also proposes a method for treating coated sand by roasting and regenerating, comprising the following steps: S1: Adding old sand into the old sand hopper of the above-mentioned coated sand roasting and regeneration processing device; S2: The old sand in the old sand hopper is continuously added into the outer cylinder of the heat exchange device; S3: The old sand in the preheating chamber flows from the low temperature section to the high temperature section, absorbing the heat transferred from the outer wall of the inner cylinder, and the temperature gradually rises, and the old sand is preheated; S4: The preheated old sand enters the second preheating sand hopper, and the screw conveyor conveys the preheated old sand to the elevator, and the elevator conveys the preheated old sand to the first preheating sand hopper; S5: The sand in the first preheating sand hopper is continuously fed into the furnace of the roasting furnace by a screw conveyor; S6: The preheated old sand is fully heat-exchanged with the furnace in the rotating furnace, and the temperature is quickly raised to the roasting temperature of 700-800°C, and maintained at this temperature for 5-30 minutes; S7: The roasted high-temperature sand continuously enters the high-temperature aging silo and is kept for 1-5 hours; S8: The matured high-temperature sand continuously enters the inner cylinder of the heat exchange device. The rotating inner cylinder drives the high-temperature sand to flow forward slowly and transfers the heat to the inner cylinder. The inner cylinder then transfers the heat to the old sand that needs to be preheated in the outer cylinder of the heat exchange device, thereby achieving cooling of the high-temperature sand and preheating of the old sand. S9: The regenerated sand cooled by the heat exchange device enters the regenerated sand silo; S10: The regenerated sand can enter the coating process through the discharge port of the regenerated sand silo.

[0016] Preferably, in step S1, the old sand is directly added into the first preheating sand hopper or the second preheating sand hopper.

[0017] The beneficial effects of the present invention are as follows: the present invention is provided with a heat exchange device, and the rotating inner cylinder body makes the high-temperature sand after roasting cool and the old sand preheat synchronously, so as to realize the maximum utilization of thermal energy; when the inner cylinder body rotates, the inner spiral conveying mechanism of the inner wall drives the high-temperature sand to flow slowly forward, and the high-temperature sand on the outer side slowly moves in the opposite direction under the action of the outer spiral blades, and the rotating inner cylinder body gradually transfers the internal high temperature to the external old sand to preheat the old sand; the heat exchange structure arranged on the inner and outer walls increases the contact area between the molding sand and the cylinder body on both sides, and improves the heat exchange efficiency; the outer wall of the furnace of the roasting furnace is a raised reinforcement structure, which increases the strength of the furnace structure on the one hand, and increases the heating area on the other hand, and improves the heat exchange efficiency; the inner wall of the furnace is a needle-shaped heat-conducting protrusion, which is in full contact with the material, and improves the heat exchange efficiency; the rotating furnace structure of the roasting furnace enables the molding sand to be heated evenly when heated.

[0018] The features and advantages of the present invention will be described in detail through embodiments in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2is a schematic diagram of a heat exchange device of the present invention; Figure 3 It is a schematic diagram of a roasting furnace of the present invention.

[0020] In the figure: 1. Old sand hopper; 4. High-temperature aging silo; 5. Roasting furnace; 6. First screw feeder; 7. First preheating sand hopper; 8. Elevator; 9. Second preheating sand hopper; 10. Second screw feeder; 11. Regenerated sand silo; 31. Inner screw conveying mechanism; 32. Outer screw blades; 33. Bracket; 34. Driving motor; 35. Feed cover plate; 36. Discharge cover plate; 37. Heat exchange structure; 51. Heating furnace; 52. Rotating furnace core; 53. Rotating motor; 54. Screw conveying trough; 55. Heat-conducting protrusion; 56. Reinforcing ribs; 57. Feed baffle; 58. Discharge baffle. DETAILED DESCRIPTION

[0021] See also Figure 1 , Figure 2 , Figure 3 A coated sand roasting and regeneration processing device, comprising an old sand hopper 1, a heat exchange device, a high-temperature aging silo 4, a roasting furnace 5, a first screw feeder 6, a first preheating sand hopper 7, an elevator 8, a second preheating sand hopper 9, a second screw feeder 10 and a regenerated sand silo 11, the heat exchange device comprises an outer cylinder 2 and an inner cylinder 3, the feed side of the inner cylinder 3 is connected to the discharge end of the high-temperature aging silo 4, the discharge side of the inner cylinder 3 is connected to the feed end of the regenerated sand silo 11, the feed side of the outer cylinder 2 is connected to the discharge end of the old sand hopper 1 The discharge end of the outer cylinder 2 is connected to the feed end of the second preheating sand hopper 9, the discharge end of the second preheating sand hopper 9 is connected to the feed end of the elevator 8, the discharge end of the elevator 8 is connected to the feed end of the second screw feeder 10, the discharge end of the second screw feeder 10 is connected to the feed end of the first preheating sand hopper 7, the discharge end of the first preheating sand hopper 7 is connected to the feed end of the roasting furnace 5, and the discharge end of the roasting furnace 5 is connected to the feed end of the high-temperature aging silo 4.

[0022] An inner cylinder 3 is rotatably installed inside the outer cylinder 2, a preheating space for preheating old sand is provided between the outer cylinder 2 and the inner cylinder 3, a cooling space for cooling hot sand is provided inside the inner cylinder 3, an inner spiral conveying mechanism 31 is provided on the inner wall of the inner cylinder 3, the inner spiral conveying mechanism 31 is a spiral protrusion or a spiral groove, an outer spiral blade 32 is provided on the outer wall of the inner cylinder 3, the spiral direction of the outer spiral blade 32 and the inner spiral conveying mechanism 31 are opposite, the inner cylinder 3 is connected to a driving mechanism, and the driving mechanism drives the inner cylinder 3 to rotate.

[0023] The driving mechanism includes a bracket 33 and a driving motor 34. The two ends of the inner cylinder 3 are arranged to pass through the two ends of the outer cylinder 2. A bracket 33 is provided below the inner cylinder 3. The part of the inner cylinder 3 protruding from the outer cylinder 2 is rotatably mounted on the bracket 33. A rotating gear is provided on the inner cylinder 3. The rotating gear is meshed with a driving gear, and the driving gear is connected to the driving motor 34.

[0024] A feed cover plate 35 is rotatably mounted on the feed end of the inner cylinder 3, a hot sand inlet is provided on the feed cover plate 35, and the hot sand inlet is connected to the high-temperature aging silo 4 through a feed hopper, a discharge cover plate 36 is rotatably mounted on the discharge end of the inner cylinder 3, a hot sand outlet is provided on the discharge cover plate 36, and the hot sand outlet is connected to the regenerated sand silo 11 through a discharge hopper, the discharge end of the inner cylinder 3 is located on the feed end side of the outer cylinder 2; the feed end of the inner cylinder 3 is located on the discharge end side of the outer cylinder 2; raised heat exchange structures 37 are provided on the inner and outer walls of the inner cylinder 3; the heat exchange structure is a columnar body or a sheet body.

[0025] The roasting furnace 5 comprises a heating furnace 51 and a rotating furnace 52. A rotating rotating furnace 52 is installed inside the heating furnace 51. The rotating furnace 52 is rotated by a rotating motor 53. Both ends of the rotating furnace 52 penetrate the two ends of the heating furnace 51. A spiral conveying groove 54 is arranged on the inner wall of the rotating furnace 52. A roasting chamber is arranged inside the rotating furnace 52. A plurality of heat-conducting protrusions 55 are arranged on the inner wall of the rotating furnace 52. A protruding reinforcing rib 56 is arranged on the outer wall of the rotating furnace 52. The heating furnace 51 comprises an upper furnace body and a lower furnace body. The upper furnace body and the lower furnace body are arranged on the rotating furnace 52, respectively. On the upper and lower sides of the furnace core 52, the heating furnace 51 is a resistance heating furnace, and heating resistance wires are provided in the upper furnace body and the lower furnace body; the rotating furnace core 52 is provided with a feed hopper, and a feed baffle 57 is rotatably installed at one end thereof, and a feed hole connected to the roasting chamber is opened on the feed baffle 57, and the feed hole is connected to the discharge end of the first screw feeder 6, and the feed hopper is connected to the feeding device, and the rotating furnace core 52 is provided with a discharge hopper, and a discharge baffle 58 is rotatably installed at one end thereof, and a discharge hole connected to the roasting chamber is opened on the discharge baffle 58, and the discharge hole is connected to the feed end of the high-temperature aging silo 4.

[0026] A method for roasting and regenerating coated sand, comprising the following steps: S1: Adding old sand into the old sand hopper 1 of the coated sand roasting and regeneration treatment device; S2: The used sand in the used sand hopper 1 is continuously added into the outer cylinder 2 of the heat exchange device; S3: The old sand in the preheating chamber flows from the low temperature section to the high temperature section, absorbing the heat transferred from the outer wall of the inner cylinder 3, and the temperature gradually rises, and the old sand is preheated; S4: The preheated old sand enters the second preheating sand hopper 9, and the preheated old sand is transported to the elevator 8 by the screw conveyor, and then transported to the first preheating sand hopper 7 by the elevator 8; S5: The sand in the first preheating sand hopper 7 is continuously fed into the furnace of the roasting furnace 5 by a screw conveyor; S6: The preheated old sand is fully heat-exchanged with the furnace in the rotating furnace 52, and the temperature is quickly raised to the roasting temperature of 750-800°C, and maintained at this temperature for 5-30 minutes; S7: The roasted high-temperature sand continuously enters the high-temperature aging silo 4 and is kept for 2-3 hours; S8: The matured high-temperature sand continuously enters the inner cylinder 3 of the heat exchange device. The rotating inner cylinder 3 drives the high-temperature sand to flow forward slowly and transfers the heat to the inner cylinder 3. The inner cylinder 3 then transfers the heat to the old sand that needs to be preheated in the outer cylinder 2 of the heat exchange device, thereby achieving cooling of the high-temperature sand and preheating of the old sand. S9: The regenerated sand cooled by the heat exchange device enters the regenerated sand silo 11; S10: The regenerated sand can enter the coating process through the discharge port of the regenerated sand silo 11.

[0027] The old sand can also be directly added into the first preheating sand hopper 7 or the second preheating sand hopper 9; the old sand directly enters the roasting furnace 5 for roasting.

[0028] The above embodiments are intended to illustrate the present invention, not to limit the present invention. Any solution that is a simple transformation of the present invention belongs to the protection scope of the present invention.

Claims

1. A coated sand roasting and regeneration treatment device, characterized in that: The invention comprises a used sand hopper (1), a heat exchange device, a high-temperature aging silo (4), a roasting furnace (5), a first screw feeder (6), a first preheating sand hopper (7), an elevator (8), a second preheating sand hopper (9), a second screw feeder (10) and a regenerated sand silo (11), wherein the heat exchange device comprises an outer cylinder (2) and an inner cylinder (3), wherein the feed side of the inner cylinder (3) is connected to the discharge end of the high-temperature aging silo (4), the discharge side of the inner cylinder (3) is connected to the feed end of the regenerated sand silo (11), and the feed side of the outer cylinder (2) is connected to the discharge end of the used sand hopper (1). The discharge side of the outer cylinder (2) is connected to the feed end of the second preheating sand hopper (9), the discharge end of the second preheating sand hopper (9) is connected to the feed end of the elevator (8), the discharge end of the elevator (8) is connected to the feed end of the second screw feeder (10), the discharge end of the second screw feeder (10) is connected to the feed end of the first preheating sand hopper (7), the discharge end of the first preheating sand hopper (7) is connected to the feed end of the roasting furnace (5), and the discharge end of the roasting furnace (5) is connected to the feed end of the high-temperature aging silo (4).

2. The coated sand roasting and regeneration treatment device according to claim 1, characterized in that: The outer cylinder (2) and the inner cylinder (3) are connected to each other. A preheating space for preheating old sand is provided between the outer cylinder (2) and the inner cylinder (3). An inner spiral conveying mechanism (31) is provided on the inner wall of the inner cylinder (3). The inner spiral conveying mechanism (31) is a spiral protrusion or a spiral groove. An outer spiral blade (32) is provided on the outer wall of the inner cylinder (3). The spiral directions of the outer spiral blade (32) and the inner spiral conveying mechanism (31) are opposite. The outer cylinder (2) or the inner cylinder (3) is connected to a driving mechanism. The driving mechanism drives the outer cylinder (2) and the inner cylinder (3) to rotate together.

3. The coated sand roasting and regeneration treatment device according to claim 2, characterized in that: The driving mechanism comprises a bracket (33) and a driving motor (34); two ends of the inner cylinder (3) are arranged to penetrate two ends of the outer cylinder (2); a bracket (33) is arranged below the inner cylinder (3); a portion of the inner cylinder (3) protruding from the outer cylinder (2) is rotatably mounted on the bracket (33); a rotating gear is arranged on the inner cylinder (3); the rotating gear is meshed with a driving gear; and the driving gear is connected to the driving motor (34).

4. The coated sand roasting and regeneration treatment device according to claim 3, characterized in that: A feed cover plate (35) is rotatably mounted on the feed end of the inner cylinder (3), a hot sand inlet is formed on the feed cover plate (35), and the hot sand inlet is connected to the high-temperature aging bin (4) through a feed hopper; a discharge cover plate (36) is rotatably mounted on the discharge end of the inner cylinder (3), a hot sand outlet is formed on the discharge cover plate (36), and the hot sand outlet is connected to the regenerated sand bin (11) through a discharge hopper; the discharge end of the inner cylinder (3) is located on one side of the feed end of the outer cylinder (2); the feed end of the inner cylinder (3) is located on one side of the discharge end of the outer cylinder (2).

5. The coated sand roasting and regeneration treatment device according to claim 1, characterized in that: The inner wall and the outer wall of the inner cylinder (3) are both provided with raised heat exchange structures (37).

6. The coated sand roasting and regeneration treatment device according to claim 1, characterized in that: The heat exchange mechanism is a columnar body or a sheet body.

7. The coated sand roasting and regeneration treatment device according to claim 1, characterized in that: The roasting furnace (5) comprises a heating furnace (51) and a rotating furnace core (52). The heating furnace (51) is a resistance heating furnace, an electromagnetic induction heating furnace or a gas furnace. The rotating furnace core (52) is arranged in the furnace chamber of the heating furnace (51). The rotating furnace core (52) is rotated by a rotating motor (53). Both ends of the rotating furnace core (52) penetrate through both ends of the heating furnace (51). A spiral conveying groove (54) is arranged on the inner wall of the rotating furnace core (52). A plurality of heat exchange protrusions (55) are arranged on the inner wall of the rotating furnace core (52). 2) is provided with reinforcing ribs (56) on the outer wall; the rotating furnace core (52) is provided with a feed hopper and a feed baffle (57) is installed at one end thereof, a feed hole connected to the roasting chamber is formed on the feed baffle (57), the feed hole is connected to the discharge end of the first screw feeder (6), the feed hopper is connected to the feeding device, the rotating furnace core (52) is provided with a discharge baffle (58) at one end of the discharge hopper, a discharge baffle (58) is provided with a discharge hole connected to the roasting chamber, and the discharge hole is connected to the feed end of the high-temperature aging bin (4).

8. A method for roasting and regenerating coated sand, characterized in that: The following steps are involved: S1: adding old sand into the old sand hopper (1) of the coated sand roasting and regeneration treatment device as claimed in claim 1; S2: the old sand in the old sand hopper (1) is continuously added into the outer cylinder (2) of the heat exchange device; S3: the old sand in the preheating chamber flows from the low temperature section to the high temperature section, absorbing the heat transferred from the outer wall of the inner cylinder (3), and the temperature gradually rises, and the old sand is preheated; S4: the preheated old sand enters the second preheating sand hopper (9), the screw conveyor conveys the preheated old sand to the elevator (8), and the elevator (8) conveys the preheated old sand to the first preheating sand hopper (7); S5: The sand in the first preheating sand hopper (7) is continuously fed into the furnace of the roasting furnace (5) by a screw conveyor; S6: The preheated old sand is fully heat-exchanged with the furnace in the rotating furnace (52), and the temperature is quickly raised to the roasting temperature of 700-800°C, and maintained at this temperature for 5-30 minutes; S7: The roasted high-temperature sand continuously enters the high-temperature aging silo (4) and is kept there for 1-5 hours; S8: The matured high-temperature sand continuously enters the inner cylinder (3) of the heat exchange device. The rotating inner cylinder (3) drives the high-temperature sand to flow slowly forward and transfers heat to the inner cylinder (3). The inner cylinder (3) then transfers the heat to the old sand that needs to be preheated in the outer cylinder (2) of the heat exchange device, thereby achieving cooling of the high-temperature sand and preheating of the old sand. S9: The regenerated sand cooled by the heat exchange device enters the regenerated sand silo (11); S10: The regenerated sand can enter the coating process through the discharge port of the regenerated sand bin (11).

9. The method for roasting and regenerating coated sand according to claim 8, characterized in that: In step S1, the old sand is directly added to the first preheating sand hopper (7) or the second preheating sand hopper (9).

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