A hierarchical scrap preheating device and preheating method

Abstract

The present invention relates to the technical field of iron and steel metallurgy, and discloses a hierarchical scrap preheating device and a preheating method, including: a hopper conveying device; a preparation mechanism; a discharging mechanism; a grading treatment device, and each group of grading treatment devices includes a scrap batching machine and a regenerative baking device. The present invention has the following advantages and effects: for the hierarchical scrap preheating device and the preheating method of the present application, since the grading treatment device is utilized, scrap materials can be laid in one layer and heated once, and batching and preheating are carried out in multiple levels and multiple times, finally making the temperature of the scrap material pile uniform and stable; on the other hand, in the present invention, lighter scrap materials can be added first during grading feeding, and then heavier scrap materials with a larger bulk density are added, and the bulk density of the scrap is adjusted by means of the self-weight of the scrap materials to ensure the loading amount of the scrap materials. At the same time, the present application can be flexibly adjusted according to requirements and can adapt to different steelmaking processes.

Description

Technical Field

[0001] This application relates to the technical field of iron and steel metallurgy, and particularly relates to a hierarchical scrap preheating device and a preheating method. Background Art

[0002] At present, the increasing intensity of environmental supervision and the establishment of carbon emission trading systems across the country have created conditions for steel enterprises to increase the utilization of scrap. Compared with the smelting process of the long process "ore - hot metal - billet", scrap can significantly reduce air and water pollution emissions. Under the strict environmental protection requirements, Chinese steel enterprises have a relatively high enthusiasm for applying scrap steel, the application ratio of scrap has increased significantly, and the proportion of short - process steelmaking has shown an obvious upward trend.

[0003] At present, there is no mature continuous scrap preheating equipment for steelmaking in China. Some existing preheating devices mainly include the following types:

[0004] 1. Hot metal ladle scrap preheating device, that is, scrap is added into the hot metal ladle and sent to the preheating station, and the scrap is preheated to about 600°C using the gas in the steel plant, and then sent to the blast furnace to compete for hot metal. The advantages of this method are high scrap preheating temperature and fast preheating speed; the disadvantages are extremely limited charging capacity, difficult to use on a large scale, large temperature difference in the hot metal ladle, and affecting the life of the hot metal ladle.

[0005] 2. Post - furnace on - line preheating device: That is, strictly classified scrap is sent into the heating furnace through a crawler conveyor for preheating, and the preheated scrap is poured into a hopper and then transported to the front of the steelmaking furnace. This method has high requirements for scrap, complex structure, high site requirements, large investment, and cannot guarantee the loading capacity of the hopper.

[0006] 3. Scrap briquette preheating device, that is, scrap is first pressed into briquettes of a unified specification, and then sent to the preheating furnace for heating using a walking device or a pusher. After heating, the briquette materials are transported to the front of the furnace through a hopper. The advantages of this method are high scrap preheating temperature, easy control of the furnace atmosphere, and large output. The disadvantages are that a scrap briquetting device needs to be added, there are restrictions on the scrap used for briquetting, complex structure, large site requirements, and high investment.

[0007] 4. Scrap bulk continuous preheating device, that is, scrap bulk is loaded into a trolley and then enters the preheating furnace, runs under the traction of a moving device, tilts to a feeding trolley at the back of the furnace, and is transported to the front of the furnace for feeding. This method has a low preheating temperature and a small preheating amount, and is only suitable for small - batch scrap preheating of medium - frequency furnaces and other small electric furnaces.

[0008] 5. Tunnel kiln - like continuous pre - heating device, where scrap steel is placed on a chain plate driven by a sprocket and moves in opposite directions to the high - temperature flue gas in the furnace. It is heated in the furnace, unloaded into a hopper at the discharge port and then transported to the front of the furnace. The advantages of this method are strong continuity and uniform pre - heating temperature. The disadvantages are small output, inability to guarantee the loading capacity of the hopper, and difficulty in matching with the steel - making process. Summary of the Invention

[0009] Aiming at the defects existing in the prior art, the purpose of this application is to provide a stepped scrap - steel pre - heating device and a pre - heating method. On the one hand, it can increase the stacking density in the scrap - steel hopper, and on the other hand, it can pre - heat so that the waste materials in the scrap - steel hopper are heated more evenly, realizing continuous and large - batch uniform pre - heating of scrap steel.

[0010] To achieve the above - mentioned purpose, on the one hand, the technical solution adopted is:

[0011] This application provides a stepped scrap - steel pre - heating device, including:

[0012] A hopper conveying device, which is erected on the ground, and several scrap - steel hoppers are erected on the hopper conveying device;

[0013] A preparatory mechanism, which is installed at the starting point of the hopper conveying device according to the transportation direction of the hopper conveying device;

[0014] A discharging mechanism, which is installed at the end point of the hopper conveying device according to the transportation direction of the hopper conveying device;

[0015] A stepped treatment device, the number of which is at least three groups, located between the preparatory mechanism and the discharging mechanism. Each group of stepped treatment devices straddles the hopper conveying device and is higher than the scrap - steel hopper. Each group of stepped treatment devices includes a scrap - steel distributing machine and a regenerative baking device arranged in sequence according to the transportation direction of the hopper conveying device.

[0016] Preferably, the scrap - steel distributing machine includes:

[0017] A distributing support, which straddles above the hopper conveying device and is higher than the scrap - steel hopper;

[0018] A scrap - steel preparation bin, which is installed on the distributing support;

[0019] A discharging elevator, the output end of which is fixedly connected to the bottom of the distributing support, and the discharging elevator is lower than the scrap - steel preparation bin.

[0020] Preferably, the regenerative baking device includes:

[0021] A baking support, which straddles above the hopper conveying device and is higher than the scrap - steel hopper;

[0022] At least one set of composite roasters, which are installed on the roaster bracket and arranged perpendicular to the conveying direction of the hopper conveying device;

[0023] The hopper elevator is correspondingly arranged below the composite roaster and is lower than the scrap hopper when the hopper elevator is not raised.

[0024] Preferably, each of the composite roasters includes:

[0025] A plurality of composite roasting covers, which are installed on the roaster bracket perpendicular to the conveying direction of the hopper conveying device;

[0026] A plurality of regenerative burners, and at least one regenerative burner is arranged at the bottom of each composite roasting cover.

[0027] Preferably, the plurality of regenerative burners are divided into at least two groups, and the number of regenerative burners in each group is at least six or more, and a group of regenerative burners is arranged at the bottom of each composite roasting cover.

[0028] Preferably, when the hopper elevator is fully raised, the whole formed by all the composite roasting covers in each group of composite roasters and the scrap hopper are buckled with each other.

[0029] Preferably, the hopper conveying device is a double-chain conveying line, and the scrap hopper straddles the two chains.

[0030] Preferably, the preparation mechanism includes:

[0031] The front load-bearing plate, on the top of which there is a front clutch groove, and the double-chain conveying line passes through the front load-bearing plate through the front clutch groove;

[0032] The front elevator, which is arranged at the bottom of the front load-bearing plate;

[0033] Four hopper adjustment mechanisms are arranged at the four corners of the front load-bearing plate. After the front elevator is fully lowered, the top surface of the hopper adjustment mechanism is lower than the top surface of the chain.

[0034] Preferably, the discharging mechanism includes:

[0035] The rear load-bearing plate, on the top of which there is a rear clutch groove, and the double-chain conveying line passes through the rear load-bearing plate through the rear clutch groove;

[0036] The rear elevator, which is arranged at the bottom of the rear load-bearing plate.

[0037] This application also provides a preheating method based on the above-mentioned hierarchical scrap preheating device, including the following steps:

[0038] S1. Place the empty scrap hopper on the preparation mechanism and send it into the hopper conveying device by the preparation mechanism;

[0039] S2. The scrap hopper enters each set of classification and treatment devices in sequence along the conveying direction; in each set of classification and treatment devices, it is first conveyed under the scrap steel spreader and filled with scrap steel materials with a low bulk density; then it is conveyed under the regenerative baking device to bake the stacked scrap steel materials to a specified temperature; and the bulk density of the scrap steel materials input by the latter scrap steel spreader is higher than that of the previous one.

[0040] S3. The scrap hopper filled with high-temperature scrap steel materials is sent out through the discharging mechanism.

[0041] The beneficial effects brought by the technical solution provided in this application include:

[0042] For the classified scrap steel preheating device and preheating method of this application, due to the use of the classification and treatment device, the scrap hopper is conveyed through the hopper conveying device and successively passes under the classification and treatment device, and the classification and treatment devices are arranged in sequence along the conveying direction with a scrap steel spreader and a regenerative baking device. The scrap steel materials in the scrap hopper can be heated once for each layer laid, and multiple-stage and multiple-time batching and preheating are carried out, finally making the temperature of the scrap steel material pile uniform and stable.

[0043] On the other hand, in the classified feeding of the present invention, relatively light scrap steel materials such as steel wires, steel wires, steel pipes, and thin steel plates can be added first, and then heavy scrap steel materials with a larger bulk density such as thick steel plates and large steel pipes can be added. The bulk density of the scrap steel is adjusted by means of the self-weight of the scrap steel materials to ensure the loading amount of the scrap steel materials. At the same time, the feeding device and baking time of the scrap steel preheating device provided in this application can be flexibly adjusted according to requirements, and it can adapt to different steelmaking processes. Description of the Drawings

[0044] In order to more clearly illustrate the technical solutions in the embodiments of this application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0045] Figure 1 It is the front view of an embodiment in this application.

[0046] Figure 2 It is Figure 1 the structural schematic diagram of the scrap steel spreader in

[0047] Figure 3 It is Figure 1 the structural schematic diagram of the regenerative baking device in

[0048] Figure 4 It is Figure 1 the top view schematic diagram of the preparatory mechanism in

[0049] Figure 5 is Figure 1 the structural schematic diagram when the preparatory mechanism descends in

[0050] Figure 6 is Figure 1 the structural schematic diagram when the preparatory mechanism ascends in

[0051] Figure 7 is Figure 1 the structural schematic diagram when the discharging mechanism descends in

[0052] Reference numerals:

[0053] 1. Hopper conveying device; 11. Chain; 2. Preparatory mechanism; 21. Front bearing plate; 22. Front lift; 23. Hopper adjustment mechanism; 24. Front clutch groove; 3. Discharging mechanism; 31. Rear bearing plate; 32. Rear lift; 33. Rear clutch groove; 4. Classification treatment device; 41. Scrap steel spreader; 411. Spreader support; 412. Scrap steel preparation bin; 413. Unloading lift; 42. Regenerative baking device; 421. Baking device support; 422. Composite baking device; 4221. Composite baking cover; 4222. Regenerative burner; 423. Hopper lift; 5. Scrap steel hopper. Specific embodiments

[0054] In order to make the objectives, technical solutions and advantages of the present application clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0055] In this embodiment, as Figure 1As shown in the figure, the hierarchical scrap preheating device includes a hopper conveyor device 1, a preparation mechanism 2, a discharging mechanism 3, and a classification processing device 4. The hopper conveyor device 1 is installed on the ground and is used to transport the scrap hopper 5. Taking the hopper conveying direction as the front, the above-mentioned preparation mechanism 2 is arranged at the front end of the hopper conveyor device 1, and the above-mentioned discharging mechanism 3 is arranged at the end of the hopper conveyor device 1 to assist the scrap hopper 5 to be stably placed on the hopper conveyor device 1. And the classification processing device 4 has at least three groups, which are transversely arranged across the hopper conveyor device 1 and are higher than the scrap hopper 5, and are used for distributing and heating the scrap hopper 5. Each group of classification processing devices 4 has a scrap distributing machine 41 and a regenerative baking device arranged in sequence according to the conveying direction of the hopper conveyor device 1. The scrap distributing machine 41 is used for laying a layer of scrap, and the regenerative baking device 42 is used for heating this layer of scrap to achieve the effect of laying and heating layer by layer. And each scrap distributing machine 41 lays down scrap with a gradually increasing bulk density in sequence, and the later-stacked scrap can compact the previously stacked scrap. And the previously stacked scrap has been heated and softened, and can be well compacted even by the self-weight of the later-stacked scrap, making full use of energy without the need for traditional scrap pretreatment devices.

[0056] In some embodiments, as Figure 2 shown, the scrap distributing machine 41 includes a distributing support 411, a scrap preparation bin 412, and a discharging elevator 413. The distributing support 411 is usually installed on other supports in the factory environment to have a certain height, and in some embodiments, it can also be installed on fixed piers. The scrap preparation bin 412 is installed on the distributing support 411, and the discharging elevator 413 is fixedly arranged, generally on fixed piers or supports. The output end of the discharging elevator 413 is fixedly connected to the distributing support 411, so that the discharging elevator 413 drives the scrap preparation bin 412 to move up and down. When the scrap preparation bin 412 abuts against the scrap hopper 5, the scrap is sent from the scrap preparation bin 412 into the scrap hopper 5 to complete one-time distribution.

[0057] In some embodiments, as Figure 3As shown in the figure, the regenerative baking device 42 includes a baking device support 421, a composite baking device 422, and a hopper elevator 423. The baking device support 421 is spanned above the hopper conveyor 1 and is generally fixedly installed on the pier columns or supports in the factory, so that the baking device support 421 is higher than the scrap steel hopper 5 to avoid affecting the operation of the scrap steel hopper 5. A composite baking device 422 is provided on the baking device support 421, and the number is at least one group. In some embodiments, there may be two groups or more groups. A hopper elevator 423 is correspondingly provided below each composite baking device 422. The hopper elevator 423 is used to lift the scrap steel hopper 5 so that the upper opening of the scrap steel hopper 5 is close to the composite baking device 422. On the one hand, it reduces the heat loss when the scrap steel hopper 5 is heated, and on the other hand, it can avoid the leakage of flames and potential safety hazards.

[0058] Further, as Figure 1 and Figure 3 shown, each composite baking device 422 includes at least one composite baking cover 4221 and at least one regenerative burner 4222. The composite baking cover 4221 is installed in the baking device support 421 to carry the regenerative burner 4222. The regenerative burner 4222 is used to provide flames to heat the scrap steel, and at the same time, in order to arrange more regenerative burners 4222 in a wider range, the number of composite baking covers 4221 is usually set to be multiple. As Figure 1 and Figure 3 shown in the embodiment, each group of composite baking devices 422 has two composite baking covers 4221.

[0059] Even further, as Figure 3 shown, the multiple regenerative burners 4222 are divided into at least two groups, and the number of each group of regenerative burners 4222 is at least six or more. A group of regenerative burners 4222 is provided at the bottom of each composite baking cover. Usually, the quantity of scrap steel is large, and a large heating power is required. At the same time, the scrap steel hopper 5 is generally large, so the distribution of the heaters should be as wide as possible.

[0060] Even further, as Figure 3 shown, when the hopper elevator 423 is fully raised, the composite baking cover 4221 and the scrap steel hopper 5 are buckled with each other, so that the heating flames and hot air will not leak out, further reducing the risk of fuel leakage, and at the same time making more efficient use of heat for heating.

[0061] In some embodiments, as Figure 1 and Figure 4 shown, the hopper conveyor 1 is a double-chain 11 transportation line, and the scrap steel hopper 5 is spanned on the two chains 11. The self-weight of the scrap steel hopper 5 and the relatively high temperature make it possible to extend the service life of the hopper conveyor 1 by using the double-chain 11.

[0062] Further, as Figures 4 - 6As shown, the preparatory mechanism 2 includes a front load-bearing plate 21, a front elevator 22, and a hopper adjustment mechanism 23. A front clutch slot 24 is provided at the top of the front load-bearing plate 21, through which the chain 11 is inserted. In some embodiments, the front load-bearing plate 21 is a relatively thick, heat-resistant plate to support the heavy scrap hopper 5 without deformation. When the scrap hopper 5 is placed on the front load-bearing plate 21, the hopper adjustment mechanism will adjust the position of the scrap hopper 5 to prevent the scrap hopper 5 from being misaligned and causing flames or scrap leakage during subsequent processes. Once the scrap hopper 5 is adjusted, the front elevator 22 drives the front load-bearing plate 21 downward, and the chain 11 of the hopper conveying mechanism moves upward, leaving the front clutch slot 24, and the scrap hopper 5 is lifted and transported by the chain 11.

[0063] Further, such as Figure 1 and Figure 7 As shown, the discharging mechanism 3 includes a rear load-bearing plate 31 and a rear elevator 32. The rear load-bearing plate 31 is also in the shape of a relatively thick heat-resistant plate. A rear clutch slot 33 is provided on the top of the rear load-bearing plate 31. When the scrap steel hopper 5 is transported to the position of the discharging mechanism 3, the rear elevator 32 rises, allowing the chain 11 to enter the rear clutch slot 33, and the scrap steel hopper 5 is lifted by the rear load-bearing plate 31 and waits for transportation.

[0064] This embodiment also provides a preheating method based on the above-mentioned staged preheating device, comprising the following steps:

[0065] S1. The empty scrap hopper 5 is placed on the preparatory mechanism 2, and the preparatory mechanism 2 is fed into the hopper conveyor 1;

[0066] S2. The scrap hopper 5 sequentially enters each set of grading processing devices 4 along the conveying direction. In each set of grading processing devices 4, the scrap is first conveyed to the bottom of the scrap distributor 41, where it is loaded with scrap with a low bulk density. The scrap is then conveyed to the bottom of the heat storage and baking device 42, where the stacked scrap is baked to a specified temperature. The bulk density of the scrap fed into the subsequent scrap distributor 41 is higher than that of the previous scrap distributor 41.

[0067] S3. The scrap steel hopper 5 filled with high-temperature scrap steel is sent out through the discharging mechanism 3.

[0068] In particular, the above method is as follows in a specific embodiment:

[0069] S101. The empty scrap hopper 5 is placed on the preparatory mechanism 2, the hopper is straightened by the hopper adjustment mechanism 23, and then the front load plate 21 is lowered by the front elevator 22, so that the empty scrap hopper 5 is mounted on the double chain 11;

[0070] S201. This embodiment comprises three groups of grading processing units 4, each of which is equipped with two composite roasters 422. In this step, the empty scrap hopper 5 first enters the first group of grading processing units 4. Thin, lightweight scrap with a thickness of 500-800 mm is added to the scrap distributor 41 of the first group of grading processing units 4. The scrap is roasted in the first composite roaster 422 of the first thermal storage roaster 42 for approximately 10 minutes, heating it to a temperature of 150-300°C. The scrap is then roasted in the second composite roaster 422 for another 10 minutes, heating it to a temperature of 300-400°C. At this point, the maximum temperature difference within the scrap is less than 80°C.

[0071] S301. The scrap hopper 5 enters the second grading unit 4. 500-800 mm thick briquetted scrap is added to the scrap distributor 41 of the second grading unit 4. The scrap is then baked in the first composite baker 422 of the heat storage baking device 42 of the second grading unit 4 for approximately 10 minutes, heating it to 400-500°C. The scrap is then baked in the second composite baker 422 for another 10 minutes, heating it to 500-600°C. At this point, the maximum temperature difference within the scrap is less than 70°C.

[0072] S401. The scrap hopper 5 enters the third grading unit 4. Heavy scrap of 500-800 mm thick is added to the scrap distributor 41 of the third grading unit 4. The scrap is then baked in the first composite baking unit 422 of the heat storage baking unit 42 of the third grading unit 4 for approximately 10 minutes, heating it to 600-700°C. The scrap is then baked in the second composite baking unit 422 for another 10 minutes, heating it to 700-800°C. At this point, the maximum temperature difference within the scrap is less than 50°C.

[0073] S501. The scrap steel hopper 5 moves to the discharging mechanism 3 and performs the discharging operation.

[0074] In existing scrap preheating devices, the scrap steel is often piled up and then heated in piles. Generally, the height of the scrap steel layer in the scrap hopper 5 is about 2 meters, and the flame cannot penetrate to the bottom. Because the scrap steel pile has a large porosity and a large heat dissipation surface, the temperature difference between the top and the bottom of the pile is extremely large. The average temperature at the top can reach about 1000°C, while the bottom temperature is only about 150°C within the heating time allowed by the steelmaking process. The baking temperature is extremely uneven, which also causes great damage to the hopper. If the scrap steel is not fully heated at the bottom, it is impossible to ensure that impurities such as moisture are removed, which will have an adverse effect on the steelmaking furnace. However, using the preheating device and preheating system provided in this embodiment, the temperature between the top and the bottom is more uniform, which has a smaller impact on steelmaking. At the same time, the charging method of gradually increasing the stacking density can increase the charging amount by about 10% to 20%.

[0075] This application is not limited to the above embodiments. For those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications are also considered within the protection scope of the present invention.

Claims

1. A hierarchical scrap preheating device, characterized in that, Including: A hopper conveyor device (1) is erected on the ground, and a number of scrap steel hoppers (5) are erected on the hopper conveyor device (1); A preparatory mechanism (2) is installed at the starting point of the hopper conveyor device (1) in the transportation direction of the hopper conveyor device (1); A discharging mechanism (3) is installed at the end point of the hopper conveyor device (1) in the transportation direction of the hopper conveyor device (1); There are at least three grading treatment devices (4), which are located between the preparatory mechanism (2) and the discharging mechanism (3). Each grading treatment device (4) straddles the hopper conveyor device (1) and is higher than the scrap steel hopper (5). Each grading treatment device (4) includes a scrap steel spreader (41) and a regenerative baking device (42) arranged in sequence in the transportation direction of the hopper conveyor device (1); The scrap steel spreader (41) is used for laying a layer of scrap steel, and the regenerative baking device (42) is used for heating this layer of scrap steel; Each of the scrap steel spreaders (41) lays down scrap steel with gradually increasing bulk density in sequence; The scrap steel spreader (41) includes: A spreading support (411) straddles above the hopper conveyor device (1) and is higher than the scrap steel hopper (5); A scrap steel preparation bin (412) is installed on the spreading support (411); A discharging elevator (413), whose output end is fixedly connected to the bottom of the spreading support (411), and the discharging elevator (413) is lower than the scrap steel preparation bin (412); The regenerative baking device (42) includes: A baking support (421) straddles above the hopper conveyor device (1) and is higher than the scrap steel hopper (5); At least one group of composite burners (422) is installed on the baking support (421) and is arranged perpendicular to the transportation direction of the hopper conveyor device (1); A hopper elevator (423) is correspondingly arranged below the composite burner (422). When the hopper elevator (423) is not raised, it is lower than the scrap steel hopper (5); The hopper conveyor device (1) is a double-chain (11) conveyor line, and the scrap steel hopper (5) straddles on two chains (11); The preparatory mechanism (2) includes: A front load-bearing plate (21) has a front clutch groove (24) opened at its top, and the double-chain (11) conveyor line passes through the front load-bearing plate (21) through the front clutch groove (24); A front elevator (22) is arranged at the bottom of the front load-bearing plate (21); There are four hopper adjustment mechanisms (23), which are arranged at the four corners of the front load-bearing plate (21). When the front elevator (22) is fully lowered, the top surface of the hopper adjustment mechanism (23) is lower than the top surface of the chain (11).

2. The hierarchical scrap preheating device according to claim 1, characterized in that Each of the composite burners (422) includes: There are multiple composite baking covers (4221), which are installed on the baking support (421) perpendicular to the transportation direction of the hopper conveyor device (1); There are multiple regenerative burners (4222), and at least one regenerative burner (4222) is arranged at the bottom of each composite baking cover (4221).

3. According to the grading type scrap steel preheating device described in claim 2, characterized in that: The multiple regenerative burners (4222) are divided into at least two groups, and the number of regenerative burners (4222) in each group is at least six or more. One group of regenerative burners (4222) is arranged at the bottom of each composite baking cover.

4. The staged scrap preheating device according to claim 2, wherein: When the hopper elevator (423) is fully raised, the whole formed by all the composite baking covers (4221) in each group of composite roasters (422) is buckled with the scrap hopper (5).

5. A hierarchical scrap preheating device according to claim 1, characterized in that, The discharging mechanism (3) includes: A rear load-bearing plate (31) with a rear clutch groove (33) provided at the top thereof, and the double-chain (11) conveyor line passes through the rear load-bearing plate (31) through the rear clutch groove (33); A rear elevator (32) provided at the bottom of the rear load-bearing plate (31).

6. A preheating method for a hierarchical scrap preheating device according to any one of claims 1-5, characterized in that, Including the following steps: S1. Place the empty scrap hopper (5) on the preparation mechanism (2) and send it into the hopper conveyor device (1) by the preparation mechanism (2); S2. The scrap hopper (5) sequentially enters each group of classification treatment devices (4) along the conveying direction; in each group of classification treatment devices (4), it is first conveyed under the scrap spreader (41) to load the scrap with a low bulk density; then it is conveyed under the regenerative baking device (42) to bake the stacked scrap to a specified temperature; and the bulk density of the scrap input by the latter scrap spreader (41) is higher than that of the previous scrap spreader (41); S3. Send out the scrap hopper (5) filled with high-temperature scrap through the discharging mechanism (3).

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