Steel scrap adding system and steel scrap adding method for ladle

Abstract

The invention discloses a steel scrap adding system and method for a ladle, the steel scrap adding system for the ladle comprises a steel scrap crushing system, a feeding system, a flue gas recovery system and a discharging preheating weighing system, and all the systems are highly integrated and cooperate with one another. The technical problems of insufficient heat, low-temperature splashing, serious post-blowing and the like brought to converter steelmaking after the scrap steel ratio is increased can be effectively solved, the weight of crushed scrap steel raw materials added into a ladle at each station after preheating is accurately controlled, and meanwhile, the crushed scrap steel raw materials are further preheated by utilizing physical heat of molten iron; the defect that the temperature of the molten iron entering the converter is low due to excessive addition of the crushed scrap steel raw materials or the temperature of the molten iron entering the converter is surplus due to excessive addition of the crushed scrap steel raw materials is overcome, the scrap steel ratio of the converter is effectively increased while the technological requirement of the converter for the temperature of the molten iron entering the converter is met, and then the purposes of saving iron and increasing steel are achieved; and powerful support is provided for cost reduction and benefit increase of steel enterprises.

Description

Technical Field

[0001] The present application belongs to the technical field of converter steelmaking, and specifically relates to a scrap steel adding system and a scrap steel adding method for a ladle. Background Art

[0002] At present, in the steel production process, scrap steel is a recyclable renewable resource. Compared with the traditional long process, its CO2 emissions can be reduced by 73%, dust emissions can be reduced by 90%, and energy consumption can be reduced by 59%. Taking various factors into consideration, it is estimated that our iron ore imports will drop from 1.07 billion tons in 2019 to about 900 million tons in 2025, and further drop to 750 million tons in 2030. According to estimates, by the end of 2019, my country's total social steel reserves had reached 10.5 billion tons, and the annual scrap steel resource generation exceeded 250 million tons. Taking into account the age structure, depreciation rate and annual new reserves of my country's steel reserves, the generation of scrap steel resources will maintain an annual growth of more than 12 million tons. It is estimated that my country's total social steel reserves will reach 13 billion tons in 2025, and the generation of scrap steel resources will reach 327 million tons / year. In 2030, they will reach 15 billion tons and 355 million tons / year respectively. The huge amount of scrap steel resources will inevitably force the steel industry to shift to a pattern where scrap steel is the main raw material. Developing and increasing the scrap steel ratio entering the furnace is an important technical means for enterprises to save iron, increase steel, reduce costs and increase efficiency.

[0003] BOF steelmaking has become one of the mainstream steelmaking technologies in the world's steel production due to its many advantages such as high efficiency, precision, and sustainable development. However, as the scrap steel ratio continues to increase, the main difficulty encountered in BOF steelmaking is insufficient heat, especially in the early stage of smelting, which is prone to low-temperature splashing and poor slag removal. The consumption of steel materials and furnace maintenance are affected to a certain extent. If the amount of scrap steel is reduced, the temperature of the molten iron entering the furnace will be excessive, wasting resources. In addition, the high scrap steel ratio means that the amount of scrap steel is constantly increasing, but because the amount of scrap steel added to the scrap steel bucket has reached the limit that the scrap steel bucket can accommodate, the scrap steel stored in the scrap steel bucket often exceeds the upper edge of the scrap steel bucket, and it is very easy for scrap steel to fall during the lifting process, increasing the safety risk.

[0004] After searching, the Chinese patent number CN211112059U, the patent document with the application publication date of July 28, 2020, discloses a device for accurately adding scrap steel in a molten iron tank, including a track scale, a scrap steel adding platform, a scrap steel hopper and a hopper hydraulic cylinder. The scrap steel adding platform is arranged beside the track scale, the scrap steel hopper is installed on the scrap steel adding platform, the front side of the bottom of the scrap steel hopper is hinged with the scrap steel adding platform, the rear side of the bottom of the scrap steel hopper is hinged with the piston rod of the hopper hydraulic cylinder, the lower part of the hopper hydraulic cylinder is hinged with the middle frame of the scrap steel adding platform, and the hopper hydraulic cylinder is connected to the hydraulic station located at the lower part of the scrap steel adding platform through a hydraulic pipeline. The device accurately grasps the amount of scrap steel added to each tank according to the actual production of molten iron composition, molten iron temperature and molten iron tank capacity, effectively adjusts the temperature of the molten iron after adding scrap steel, and avoids the disadvantages of the bottom of the molten iron tank being condensed and the lid of the ladle being condensed. However, the device is still used to adjust the temperature of molten iron by adding room temperature scrap steel, and the amount of room temperature scrap steel added will be limited to a certain extent.

[0005] Chinese patent number CN210367767U, with an authorization announcement date of April 21, 2020, discloses a device for adding scrap steel to a ladle, including a ladle moving along a rail of a mixing furnace and a baking furnace arranged on one side of the rail of the mixing furnace to heat the scrap steel, a cold material adding device for adding cold scrap steel to the upper feed port of the baking furnace is arranged on one side of the baking furnace, and a hot material adding device for adding hot scrap steel to the ladle is arranged between the baking furnace and the rail of the mixing furnace, a hot air inlet is arranged on the side wall of the baking furnace, and an air duct connected to the hot air inlet is arranged at the bottom of the baking furnace, and the air duct wall of the air duct is densely covered with air outlets, a hot air furnace is fixedly arranged on one side of the baking furnace, a hot air duct is arranged between the hot air furnace and the baking furnace, and an induced draft fan for extracting air from the baking furnace is arranged above the hot air duct. The device can heat the scrap steel crushing material and add it to the ladle through the elevator, so as to improve the scrap steel ratio, reduce costs and increase efficiency. However, the device preheats the crushed scrap steel with hot air, and the calorific value of the hot air is relatively low, which affects the preheating effect to some extent.

[0006] Chinese patent number CN210711618U, with an authorization announcement date of June 9, 2020, discloses a system for adding scrap steel to molten iron carrying equipment using a belt conveyor, mainly comprising: an underground workstation; an underground silo with a weighing function is arranged on the underground workstation; a gate valve is arranged at the bottom discharge port of the underground silo; a vibrating feeder is arranged at the lower outlet of the gate valve: an above-ground workstation, a lower hopper is arranged on the above-ground workstation, and the lower hopper is suspended on a platform or supported on the floor; a molten iron carrying equipment is arranged below the lower discharge port of the lower hopper; a belt conveyor is arranged between the vibrating feeder and the lower hopper. The device has played a positive role in increasing the scrap steel ratio of the converter; recovering the waste heat of the molten iron tank and reducing energy consumption; reducing the temperature drop of the molten iron tank and increasing the refractory life of the molten iron tank. However, the device also adds scrap steel at room temperature, and the amount of scrap steel added will be limited to a certain extent. At the same time, it has no dust removal facilities. With the addition of scrap steel, the amount of smoke and dust is large, and the environmental pollution problem is serious. Summary of the invention

[0007] In response to the technical problems in the background technology such as insufficient heat, low-temperature splashing and severe after-blowing caused by the increase in the scrap steel ratio in the converter steelmaking, the present application provides a scrap steel adding system and scrap steel adding method for a ladle, by accurately controlling the weight of the crushed scrap steel raw materials added to the ladle of each workstation after preheating, and further preheating the crushed scrap steel raw materials using the physical heat of the molten iron, to avoid the defects of too much crushed scrap steel raw materials adding to cause the molten iron temperature to be low, or too little crushed scrap steel raw materials adding to cause the molten iron temperature to be excessive, so as to effectively improve the scrap steel ratio of the converter while meeting the process requirements of the converter for the molten iron temperature entering the furnace, thereby achieving the purpose of saving iron and increasing steel, and providing support for steel companies to reduce costs and increase efficiency.

[0008] The technical solution to solve the technical problem in this application is as follows:

[0009] According to one aspect of the present application, a scrap steel feeding system for a molten iron ladle is provided, which includes a scrap steel crushing system, a feeding system, a fume recovery system, and a preheating weighing system for unloading. The scrap steel crushing system includes a scrap steel crusher and a scrap steel bucket that are arranged correspondingly, a scrap steel bucket weighing device is arranged on the outside of the scrap steel bucket, and a vibrating feeder, a weighing device, and a gate valve are arranged at the bottom of the scrap steel bucket in sequence; the unloading preheating weighing system includes an upper hopper, an upper hopper weighing device arranged on the upper hopper, a high-level vibrating feeder arranged at the bottom of the upper hopper, a scrap steel preheating system arranged below the high-level vibrating feeder, a low-level vibrating feeder arranged at the bottom of the scrap steel preheating system, and a low-level vibrating feeder arranged at the bottom of the scrap steel preheating system. A low-level weighing device below the vibrating feeder and a lower gate valve and a movable chute sequentially arranged at the bottom of the low-level weighing device; the scrap steel preheating system comprises a preheating silo and an ignition and nozzle device arranged on the preheating silo, a fuel gas medium pipeline is connected to the ignition and nozzle device, and a high-level weighing device is arranged at the bottom of the preheating silo; wherein: the two ends of the feeding system correspond to the gate valve and the feeding hopper respectively, and the scrap steel preheating system is connected to the flue gas recovery system through a pipeline.

[0010] Furthermore, the scrap steel crusher is a horizontal hammer crusher, the upper and lower parts of which are respectively a feeding port and a discharge port, and the scrap steel bucket is correspondingly arranged below the discharge port.

[0011] Furthermore, the feeding system includes a first chain conveyor consisting of a head wheel, a tail wheel and a plurality of feeding chain plates, the head wheel and the tail wheel are provided with a driving motor and are movably connected by a chain, and the plurality of feeding chain plates are evenly distributed on the chain.

[0012] Furthermore, the feeding system also includes a second chain conveyor which is horizontally arranged and one side of which is located below the tail wheel of the first chain conveyor, the second chain conveyor includes two bidirectional driving wheels connected by a chain, the bidirectional driving wheels are provided with a driving motor, a plurality of unloading chain plates are evenly distributed on the chain, and the unloading preheating weighing system is respectively provided below the two bidirectional driving wheels of the second chain conveyor.

[0013] Furthermore, the first chain conveyor is arranged to be tilted upward at an acute angle, and the angle is preferably 23° to the horizon; and an alloy lining plate is welded on the inner side of the lower hopper.

[0014] Furthermore, the scrap steel preheating system also includes a feed port arranged on the top of the preheating silo and a flue gas recovery device connected to the flue gas recovery system through a pipeline. The fuel gas medium pipeline is respectively connected to a fuel gas source and a nitrogen source. The fuel gas source is preferably surplus coal gas from a steel company.

[0015] Furthermore, protective covers are respectively provided on the outer sides of the first chain conveyor and the second chain conveyor, and the protective covers are connected to the fume recovery system through pipelines.

[0016] According to another aspect of the present application, a method for adding scrap steel to a ladle is provided, which is performed by a scrap steel adding system for a ladle described in the above technical solution, a molten iron car is arranged below the unloading preheating and weighing system and the ladle is placed thereon, and the method comprises:

[0017] Crushing of scrap steel raw materials: scrap steel is crushed into scrap steel raw materials by the scrap steel crusher in the scrap steel crushing system and then discharged into the scrap steel bucket.

[0018] Loading of scrap steel raw materials: the scrap steel raw materials in the scrap steel hopper are vibrated and discharged to the weighing device by the vibrating feeder, and the scrap steel raw materials in the weighing device are discharged to the feeding system through the gate valve, and the scrap steel raw materials are transported by the feeding system and discharged into the feeding hopper of the unloading preheating weighing system.

[0019] Preheating of scrap steel raw materials: the scrap steel raw materials in the upper hopper are vibrated and fed into the preheating bin of the scrap steel preheating system through the high-position vibrating feeder, and the fuel gas is sent to the ignition and nozzle device through the fuel gas medium channel. The ignition and nozzle device is turned on to bake the scrap steel raw materials to the set temperature. During the baking process, the generated smoke is sucked into the smoke recovery system through the smoke recovery device for recovery and treatment.

[0020] Feeding of scrap steel raw materials: the scrap steel raw materials preheated in the preheating bin are vibrated and discharged to the low-level weighing device through the low-level vibrating feeder, and are discharged into the molten iron ladle through the lower gate valve and the movable chute.

[0021] Furthermore, the scrap steel raw material is scrap steel bar cuttings or thin plate crushing materials.

[0022] Furthermore, the method further comprises:

[0023] The weight m1 of the preheated scrap steel raw material to be added to the ladle is calculated according to the initial temperature of the molten iron to be added to the ladle, the temperature drop of the molten iron caused by the addition of the preheated scrap steel raw material, and the process requirement value of the converter for the temperature of the molten iron entering the furnace; according to the calculated m1 value, the low-level vibrating feeder is controlled to vibrate and discharge the preheated scrap steel raw material in the preheating bin to the low-level weighing device; when the weight of the scrap steel raw material weighed by the weighing device reaches the m1 value, the scrap steel raw material is discharged into the ladle through the lower gate valve and the movable chute; wherein, m1 satisfies the following empirical formula:

[0024] m1=(T1-T2) / a

[0025] Wherein, m1 is the weight of the preheated scrap steel raw material to be added to the ladle, kg; T1 is the initial temperature of the molten iron to be added to the ladle, °C; T2 is the process requirement of the converter for the temperature of the molten iron entering the furnace, °C; a is the temperature drop of the molten iron caused by adding 1 kg of preheated scrap steel raw material, and the value range is 0.015~0.020, °C;

[0026] The storage capacity of the scrap steel raw materials in the preheating bin, the lower hopper and the scrap steel hopper is respectively set with a lower limit value and a maximum material weight value that can be reached by each effective volume, and the storage capacity of the scrap steel raw materials in the preheating bin, the lower hopper and the scrap steel hopper is between the respective lower limit value and the maximum material weight value;

[0027] When the amount of scrap steel raw material stored in the preheating bin is less than the weight m1 of the preheated scrap steel raw material required to be added to the ladle or reaches its lower limit, the weight m4 of the scrap steel raw material to be added to the preheating bin is calculated according to the maximum weight m2 that the effective volume of the preheating bin can reach, the weight coefficient b of the type of scrap steel raw material added, and the weight m3 of the remaining scrap steel raw material in the preheating bin; according to the calculated m4 value, the high-level vibrating feeder is controlled to vibrate and feed the scrap steel raw material in the upper hopper into the preheating bin until the weight of the scrap steel raw material weighed by the high-level weighing device reaches the m4 value; wherein, m4 satisfies the following empirical formula:

[0028] m4=(m2-m3)×b

[0029] Wherein, m4 is the weight of the scrap steel raw material to be added to the preheating bin, kg; m2 is the maximum weight value that the effective volume of the preheating bin can reach, kg; m3 is the weight value of the remaining scrap steel raw material in the preheating bin, kg; b is the weight coefficient of the scrap steel raw material type. When the scrap steel raw material type is scrap steel bar cuttings, b is 1; when the scrap steel raw material type is thin plate crushing material: b is 0.5;

[0030] When the amount of scrap steel raw material stored in the lower hopper is less than the weight value m4 of the scrap steel raw material to be added to the preheating bin or reaches its lower limit, the weight m7 of the scrap steel raw material to be added to the lower hopper is calculated according to the maximum weight value m5 that the effective volume of the lower hopper can reach, the weight coefficient b of the type of scrap steel raw material added, and the weight value m6 of the remaining scrap steel raw material in the lower hopper; according to the calculated weight m7 of the scrap steel raw material to be added to the lower hopper, the vibrating feeder is controlled to vibrate and feed the scrap steel raw material in the scrap steel hopper into the weighing device until the weighing device weighs the scrap steel raw material inside and stops when the weight reaches the value m7, and the gate valve is controlled to feed the scrap steel raw material in the weighing device to the feeding system, and the scrap steel raw material is transported by the feeding system and fed into the upper hopper; wherein, m7 satisfies the following empirical formula:

[0031] m7=(m5-m6)×b

[0032] Wherein, m7 is the weight of the scrap steel raw material to be added to the lower hopper, kg; m5 is the maximum weight value that the effective volume of the lower hopper can reach, kg; m6 is the weight value of the scrap steel raw material remaining in the lower hopper, kg; b is the weight coefficient of the scrap steel raw material type. When the scrap steel raw material type is scrap steel bar cuttings, b is 1; when the scrap steel raw material type is thin plate crushed material: b is 0.5;

[0033] When the storage amount of scrap steel raw materials in the scrap steel bucket is less than the weight value m7 of the scrap steel raw materials to be added to the lower hopper or reaches its lower limit, the scrap steel crusher is controlled to crush the scrap steel into scrap steel raw materials and then discharge them into the scrap steel bucket until the scrap steel bucket weighing device measures the weight of the scrap steel raw materials and stops.

[0034] Furthermore, before the fuel gas medium channel transports the fuel gas, the fuel gas medium channel is first purged with nitrogen.

[0035] Furthermore, the set temperature of the scrap steel raw material after baking is 400-600°C.

[0036] Compared with the prior art, the scrap steel adding system and scrap steel adding method for a ladle described in the present application have the following beneficial effects:

[0037] (1) The present application sets up a scrap steel crushing system, a feeding system, a flue gas recovery system, and a preheating and weighing system for unloading as subsystems. Each subsystem is highly integrated and works together to effectively solve the problem in the prior art that too much crushed scrap steel raw material is added during converter steelmaking, resulting in a low temperature of the molten iron entering the furnace, or too little crushed scrap steel raw material is added, resulting in an excessive temperature of the molten iron entering the furnace. While meeting the converter's process requirements for the temperature of the molten iron entering the furnace, the converter scrap steel ratio is increased, thereby achieving the purpose of saving iron and increasing steel.

[0038] (2) The present application provides a scrap steel crushing system, which can crush scrap steel bar ends or thin plates on site, effectively reducing the production costs of scrap steel crushing and vehicle transportation.

[0039] (3) The scrap steel crushing system, the material preheating weighing system and the scrap steel preheating system in the present application are all equipped with a vibrating feeder and a weighing device, and the subsystems are interlocked and controlled with each other, with a high degree of automation and low labor intensity. The weight of the preheated and crushed scrap steel added to the molten iron ladle can be accurately controlled, and the scrap steel hopper, the material preheating hopper and the preheating silo can be filled in time as needed.

[0040] (4) In this application, by adding a scrap steel preheating system and utilizing the high calorific value and good baking effect of gas combustion, the crushed scrap steel can be preheated to 400-600°C in a short time, which is beneficial to improving the production rhythm.

[0041] (5) In this application, a flue gas recovery system is added. A flue gas recovery device is added to the scrap steel preheating system to recover the flue gas generated during the scrap steel baking process to avoid environmental pollution.

[0042] (6) The feeding system in this application adopts a chain plate steel structure, which has high strength and good wear resistance. While increasing the service life of the equipment, it effectively reduces the cost of spare parts consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a cross-sectional structural schematic diagram of a scrap steel adding system for a ladle of the present application from one perspective;

[0044] Figure 2 It is a cross-sectional structural schematic diagram of another perspective of a scrap steel adding system for a ladle of the present application;

[0045] Figure 3 It is a structural schematic diagram of the scrap steel crushing system in this application;

[0046] Figure 4 It is a structural schematic diagram of the feeding system in this application;

[0047] Figure 5 It is a structural schematic diagram of the material preheating and weighing system in this application;

[0048] Figure 6 It is a structural schematic diagram of the scrap steel preheating system in this application;

[0049] Figure 7 A schematic diagram of a process for adding scrap steel to a ladle in this application;

[0050] In the figure: 1. Scrap steel crushing system; 11. Scrap steel crusher; 12. Feeding port; 13. Discharging port; 14. Scrap steel bucket; 15. Vibrating feeder; 16. Weighing device; 17. Gate valve; 18. Scrap steel bucket weighing device; 2. Feeding system; 21. Feeding chain plate; 22. Head wheel; 23. Tail wheel; 24. Discharging chain plate; 25. Two-way driving wheel; 26. Protective cover; 3. Smoke recovery system; 4. Discharging preheating weighing system; 41. Upper hopper; 42. Upper hopper weighing device; 43. High-level vibrating feeder; 44. Scrap preheating system; 441. Preheating silo; 442. Ignition and nozzle device; 443. Flue gas recovery device; 444. Feed port; 445. Fuel medium pipeline; 45. High-level weighing device; 46. Low-level vibrating feeder; 47. Low-level weighing device; 48. Lower gate valve; 49. Movable chute; 6. Molten iron ladle; 7. Molten iron car; 8. Torpedo tank. DETAILED DESCRIPTION

[0051] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application. Unless otherwise defined, the technical terms or scientific terms used herein should be the usual meanings understood by people with general skills in the field to which the present disclosure belongs. The "upper", "lower", "left", "right", "front", "back" and the like used in the patent application specification and claims of the present disclosure are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship also changes accordingly; "connection" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The places not described in detail in this application are all known technologies of technicians in the field of this technology.

[0052] Example 1

[0053] like Figure 1-6 As shown, the present application provides a scrap steel charging system for a molten iron ladle, comprising: a scrap steel crushing system 1, a feeding system 2, a fume recovery system 3 and a discharge preheating weighing system 4.

[0054] The scrap steel crushing system 1 includes a scrap steel crusher 11 and a scrap steel bucket 14 which are arranged accordingly. The scrap steel crusher 11 can be a horizontal hammer crusher, and the upper and lower parts are respectively a feeding port 12 and a discharge port 13. The rotor speed is 1000r / min, and the maximum production capacity is 150t / h. The scrap steel enters the scrap steel crusher 11 from the feeding port 12, and is discharged from the discharge port 13 after being crushed. The scrap steel is mainly scrap steel bars and thin plates. The scrap steel raw materials after crushing must meet the requirements of the scrap steel preheating system for the size of the crushed scrap steel. Under normal circumstances, the scrap steel bar cut head: length 100-150mm, diameter ≤100mm, bulk density 2.5-3.2t / m 3 ; Thin plate crushed material: size 150×150×70mm or less, bulk density 1.1~1.8t / m 3The scrap steel bucket 14 is correspondingly arranged below the discharge port 13, and is used to receive the crushed scrap steel raw materials sent out from the discharge port 13. A scrap steel bucket weighing device 18 for weighing the weight of the scrap steel raw materials in the scrap steel bucket 14 is arranged on the outside of the scrap steel bucket 14, and a vibrating feeder 15, a weighing device 16 and a gate valve 17 are arranged at the bottom of the scrap steel bucket 14 in sequence. The crushed scrap steel raw materials stored in the scrap steel bucket 14 are discharged to the weighing device 16 through the vibrating feeder 15. The weighing device 16 is provided with a bin body for placing the scrap steel raw materials, and can weigh the weight of the scrap steel raw materials in the bin body at the same time. By opening or closing the gate valve 17, the scrap steel raw materials in the weighing device 16 can be discharged or stopped to the upper feeding system 2.

[0055] The feeding system 2 includes a first chain conveyor consisting of a head wheel 22, a tail wheel 23 and a plurality of feeding chain plates 21. The head wheel 22 and the tail wheel 23 are provided with driving motors and are movably connected by chains. The plurality of feeding chain plates 21 are evenly distributed on the chains. The head wheel 22 and the tail wheel 23 are driven by the driving motor to rotate, thereby driving the chain and the feeding chain plates 21 thereon to rotate, thereby realizing the transportation of the scrap steel raw materials unloaded to the feeding chain plates 21, wherein the head wheel 22 of the first chain conveyor corresponds to the gate valve 17.

[0056] As a preferred embodiment of the feeding system 2, the feeding system 2 also includes a second chain conveyor which is horizontally arranged and one side of which is located below the tail wheel 23 of the first chain conveyor. The second chain conveyor includes two bidirectional driving wheels 25 connected by a chain, and a driving motor is arranged on the bidirectional driving wheel 25. A plurality of unloading chain plates 24 are evenly distributed on the chain. Unloading preheating weighing systems 4 are respectively arranged below the two bidirectional driving wheels 25 of the second chain conveyor. The two bidirectional driving wheels 25 can be driven forward and reverse by the driving motor, so that unloading of materials by the unloading preheating weighing systems 4 on both sides can be realized, and simultaneous weighing and unloading of materials at multiple stations can be realized, thereby improving practicality.

[0057] In this embodiment, the first chain conveyor can be set to be tilted upward at an acute angle, and the angle is preferably 23° to the horizon, so as to facilitate the transportation of the scrap steel raw materials to a high position.

[0058] As a preferred embodiment, the loading chain plate 21 and the unloading chain plate 24 are both steel chain structures with wear resistance, heat resistance and other characteristics. Among them, the loading chain plate 21 is 800mm wide and 17950mm long, with an inclination of 23° to the horizon, a conveying capacity of 120t / h, a conveying speed of 0.15m / s, and the driving motor power of the head wheel 22 and the tail wheel 23 is 45kW; the unloading chain plate 24 is 800mm wide and 21600mm long, parallel to the horizon and 6800mm above the ground, with a conveying capacity of 120t / h, a conveying speed of 0.20m / s, and the driving motor power of the bidirectional driving wheel 25 is 18.5kW.

[0059] The fume recovery system 3 is used to recover the fume and the like generated when the scrap steel adding system for the ladle is used.

[0060] The material preheating weighing system 4 includes an upper hopper 41, an upper hopper weighing device 42 disposed on the upper hopper 41, a high-level vibrating feeder 43 disposed at the bottom of the upper hopper 41, a scrap steel preheating system 44 disposed below the high-level vibrating feeder 43, a low-level vibrating feeder 46 disposed at the bottom of the scrap steel preheating system 44, a low-level weighing device 47 disposed below the low-level vibrating feeder 46, and a lower gate valve 48 and a movable chute 49 disposed at the bottom of the low-level weighing device 47 in sequence. The upper hopper 41 is used to receive the scrap steel raw materials transported from the bidirectional driving wheel 25 of the second chain conveyor. As a preferred embodiment, the effective volume of the upper hopper 41 is 20m 3 The inner lining can be welded with a 12mm thick alloy lining plate, and the tank steel plate can withstand a high temperature of 450°C. The upper hopper weighing device 42 is used to weigh the weight of the scrap steel raw materials in the upper hopper 41 to accurately control the weight of the scrap steel raw materials added to the scrap steel preheating system. The high-level vibrating feeder 43 is used to discharge the scrap steel raw materials in the upper hopper 41 and send them to the scrap steel preheating system 44 for preheating. The scrap steel preheating system 44 is used to bake the delivered scrap steel raw materials, which includes a preheating bin 441 for placing and baking the scrap steel raw materials. As a preferred embodiment, the effective volume of the preheating bin 441 is 7 to 8m 3, a single preheating bin 441 can accommodate 18-20t of scrap steel bar cuttings or 9-10t of thin plate crushing materials. The top of the preheating bin 441 is provided with a feed port 444 for feeding scrap steel raw materials and a fume recovery device 443 connected to the fume recovery system 3 through a pipeline for recovering the fume generated during the baking process to avoid environmental pollution. The preheating bin 441 is provided with an ignition and nozzle device 442, and the ignition and nozzle device 442 is connected with a fuel gas medium pipeline 445, and the fuel gas medium pipeline 445 is connected to the fuel gas source and the nitrogen source respectively. The fuel gas medium pipeline 445 can be purged by nitrogen, and the fuel gas can be sent to the ignition and nozzle device 442 through the fuel gas medium pipeline 445 by the fuel gas source. After the ignition and nozzle device 442 is ignited and burned, the heat generated by the combustion of the high calorific value gas is used to bake the scrap steel raw materials stored in the preheating bin 441 online to remove moisture and impurities in the crushed scrap steel. The fuel gas can be selected from the relatively abundant gas in the plant area. A high-level weighing device 45 is provided at the bottom of the preheating bin 441, which is used to weigh the weight of the scrap steel raw materials in the preheating bin 441. The low-level vibrating feeder 46 is used to discharge the preheated scrap steel raw materials in the preheating bin 441 of the scrap steel preheating system 44, and the low-level weighing device 47 is used to place and weigh the discharged scrap steel raw materials to accurately control the weight of the preheated crushed scrap steel raw materials added to the corresponding station iron ladle. The lower plug valve 48 and the movable chute 49 are used to deliver the scrap steel raw materials in the low-level weighing device 47 to the iron ladle 6. The iron ladle 6 is placed by the iron ladle car 7, and the iron ladle 7 is set on the track. After the scrap steel raw materials are added, the iron ladle car 7 can be driven to the torpedo tank car 8, and the torpedo tank can be tilted to tap the iron ladle. As a preferred embodiment, the motor power of the high-level vibrating feeder 43 and the low-level vibrating feeder 46 is 2×1.5kW respectively.

[0061] As a preferred embodiment, protective covers 26 can be respectively provided on the outside of the first chain conveyor and the second chain conveyor. The protective covers 26 are connected to the fume recovery system 3 through a pipeline to recover the fume generated during the application of the scrap steel adding system for the ladle.

[0062] As a preferred embodiment, industrial control equipment (such as PLC, etc.) can also be set in the scrap steel adding system for the molten iron ladle to uniformly control the scrap steel crusher, various weighing devices, drive motors, vibrating feeders, ignition and burner devices, etc. in each subsystem, so that each subsystem can be automatically interlocked and controlled to operate in an orderly manner.

[0063] Example 2

[0064] like Figure 1-7 As shown, this embodiment provides a method for adding scrap steel to a ladle, which is performed by the scrap steel adding system for the ladle in Example 1, and a molten iron vehicle 7 is arranged below the unloading preheating weighing system 4 and a molten iron ladle 6 is placed thereon. The specific method includes:

[0065] Crushing of scrap steel raw materials: After the qualified scrap steel is hoisted to the feeding port 12 of the scrap steel crusher 11 by using the lower opening scrap steel trough, the scrap steel crusher 11 is turned on, the rotor speed is set to 1000r / min, the scrap steel trough is opened, and the scrap steel crusher 11 is slowly fed from the feeding port 12. After the scrap steel is crushed and becomes the scrap steel raw material for converter steelmaking, it is discharged from the discharge port 13 into the scrap steel bucket 14. In this embodiment, the scrap steel raw material is the scrap steel bar cuttings or the crushed thin plate materials.

[0066] Scrap steel raw material feeding: The scrap steel raw material in the scrap steel hopper 14 is discharged to the weighing device 16 through the vibration feeder 15, and the scrap steel raw material in the weighing device 16 is discharged to the feeding system 2 through the gate valve 17, and the scrap steel raw material is transported through the feeding system 2 and discharged into the feeding hopper 41 of the unloading preheating weighing system 4; when feeding, before the gate valve 17 is opened, the two-way driving wheel 25 in the feeding system 2 is first opened to drive the unloading chain plate 24 to operate; then the head wheel 22 and the tail wheel 23 in the feeding system 2 are opened to drive the loading chain plate 21 to operate; finally, the gate valve 17 of the scrap steel crushing system 1 is opened to add the crushed scrap steel raw material into the unloading hopper 41; after feeding, the gate valve 17 of the scrap steel crushing system 1 is first closed; then the head wheel 22 and the tail wheel 23 in the feeding system 2 are closed to stop the operation of the loading chain plate 21; finally, the two-way driving wheel 25 in the feeding system 2 is closed to stop the operation of the unloading chain plate 24, and the feeding work of the unloading hopper 41 is completed.

[0067] Preheating of scrap steel raw materials: The scrap steel raw materials in the upper hopper 41 are vibrated and discharged into the preheating bin 441 of the scrap steel preheating system 44 by the high-level vibrating feeder 43, and the fuel gas is sent to the ignition and nozzle device 442 through the fuel gas medium channel 445. The fuel gas is preferably coal gas. The ignition and nozzle device 442 is turned on to bake the scrap steel raw materials to the set temperature. During the baking process, the generated smoke is sucked into the smoke recovery system 3 for recycling and treatment through the smoke recovery device 443; as a preferred embodiment, before turning on the coal gas baking device, nitrogen can be used to purge the fuel gas medium pipeline 445, and the nitrogen flow rate is set to 50Nm 3 / h, nitrogen pressure 0.4~0.6MPa, purge time 5~6min; turn on ignition and nozzle device 442, set gas flow rate to 800Nm 3 / h, gas pressure ≥8kpa, baking for 10-15min, when the crushed scrap temperature is preheated to 400-600℃, discharge or switch to insulation state.

[0068] Scrap steel raw material feeding: the scrap steel raw material preheated in the preheating bin 441 is vibrated and discharged to the low-level weighing device 47 through the low-level vibrating feeder 46, and discharged into the molten iron ladle 6 through the lower gate valve 48 and the movable chute 49, and the molten iron ladle 6 is sent to the iron-discharging position of the torpedo tank car 8 through the molten iron car 7, and the torpedo tank is tilted to discharge the iron.

[0069] Example 3

[0070] Based on Example 2, a method for adding scrap steel to a ladle is provided, which is used to accurately, interlock and automatically control the subsystems of the scrap steel adding system for the ladle in Example 1 and the weight of the scrap steel raw materials to be added.

[0071] In this embodiment, the storage amount of the scrap steel raw materials in the preheating bin 441, the lower hopper 41 and the scrap steel hopper 14 is respectively set with a lower limit value and a maximum material weight value that can be reached by each effective volume, and the storage amount of the scrap steel raw materials in the preheating bin 441, the lower hopper 41 and the scrap steel hopper 14 is between the respective lower limit value and the maximum material weight value. When the scrap steel adding system for the ladle is initially used, the weight of the scrap steel raw materials in the preheating bin 441, the lower hopper 41 and the scrap steel hopper 14 can be stored to the maximum material weight value, and then interlock control is performed during use to automatically add materials.

[0072] The specific method is as follows:

[0073] (1) The weight m1 of the preheated scrap steel raw material to be added to the ladle 6 is calculated according to the initial temperature of the molten iron to be added to the ladle 6, the temperature drop of the molten iron caused by the addition of the preheated scrap steel raw material, and the process requirement value of the converter for the temperature of the molten iron entering the furnace; according to the calculated value of m1, the low-level vibrating feeder 46 is opened to vibrate and discharge the preheated scrap steel raw material in the preheating bin 441 to the low-level weighing device 47; when the weight of the scrap steel raw material weighed by the weighing device 47 reaches the value of m1, the low-level vibrating feeder 46 is stopped to vibrate and discharge; the lower gate valve 48 and the movable chute 49 are opened to discharge the scrap steel raw material with a preset weight of m1 into the ladle 6, and the molten iron car 7 is driven to the iron-discharging position of the torpedo tank 8, and the torpedo tank is tilted to discharge the iron; wherein, m1 satisfies the following empirical formula:

[0074] m1=(T1-T2) / a

[0075] Wherein, m1 is the weight of the preheated scrap steel raw material to be added to the ladle 6, in kg; T1 is the initial temperature of the molten iron to be added to the ladle 6, in °C; T2 is the process requirement of the converter for the temperature of the molten iron entering the furnace (generally T2 is required to be ≥1250, and the value is 1250 during calculation), in °C; a is the temperature drop of the molten iron caused by adding 1 kg of preheated scrap steel raw material, ranging from 0.015 to 0.020, in °C;

[0076] (2) When the amount of scrap steel stored in the preheating bin 441 is less than the weight m1 of the preheated scrap steel required to be added to the molten iron ladle 6 or reaches its lower limit, the weight m4 of the scrap steel to be added to the preheating bin 441 is calculated based on the maximum weight m2 of the effective volume of the preheating bin 441, the weight coefficient b of the type of scrap steel added, and the weight m3 of the remaining scrap steel in the preheating bin 441; based on the calculated value m4, the high-level vibrating feeder 43 is started to vibrate and feed the scrap steel in the upper hopper 41 into the preheating bin 441 until the weight of the scrap steel weighed by the high-level weighing device 45 reaches the value m4, and the high-level vibrating feeder 43 is closed to complete the feeding of the preheating bin 441; wherein m4 satisfies the following empirical formula:

[0077] m4=(m2-m3)×b

[0078] Wherein, m4 is the weight of the scrap steel raw material to be added to the preheating bin 441, in kg; m2 is the maximum weight value that the effective volume of the preheating bin 441 can reach, in kg; m3 is the weight value of the scrap steel raw material remaining in the preheating bin 441, in kg; b is the weight coefficient of the scrap steel raw material type, when the scrap steel raw material type is scrap steel bar cuttings, b is 1, when the scrap steel raw material type is thin plate crushing material: b is 0.5;

[0079] (3) When the amount of scrap steel raw material stored in the lower hopper 41 is less than the weight value m4 of the scrap steel raw material to be added to the preheating bin 441 or reaches its lower limit, the weight value m7 of the scrap steel raw material to be added to the lower hopper 41 is calculated according to the maximum weight value m5 that the effective volume of the lower hopper 41 can reach, the weight coefficient b of the type of scrap steel raw material added, and the weight value m6 of the remaining scrap steel raw material in the lower hopper 41; according to the calculated weight value m7 of the scrap steel raw material to be added to the lower hopper 41, the vibrating feeder 15 is started to vibrate and feed the scrap steel raw material in the scrap hopper 14 into the weighing device 16 until the weight of the scrap steel raw material weighed by the weighing device 16 reaches the value m7. Stop; before the gate valve 17 is opened, first open the two-way driving wheel 25 in the feeding system 2 to drive the unloading chain plate 24 to operate, then open the head wheel 22 and the tail wheel 23 in the feeding system 2 to drive the feeding chain plate 21 to operate, and finally open the gate valve 17 to add the crushed scrap steel raw material with a preset weight of m7 into the unloading hopper 41; when the crushed scrap steel enters the unloading hopper 41 and the unloading hopper weighing device 42 reaches the preset weight of m7, first close the gate valve 17; then close the head wheel 22 and the tail wheel 23 to stop the operation of the feeding chain plate 21; finally close the two-way driving wheel 25 to stop the operation of the unloading chain plate 24, and complete the loading work of the unloading hopper 41; wherein, m7 satisfies the following empirical formula:

[0080] m7=(m5-m6)×b

[0081] Wherein, m7 is the weight of the scrap steel raw material to be added to the lower hopper 41, in kg; m5 is the maximum weight value that the effective volume of the lower hopper 41 can reach, in kg; m6 is the weight value of the scrap steel raw material remaining in the lower hopper 41, in kg; b is the weight coefficient of the scrap steel raw material type, when the scrap steel raw material type is scrap steel bar cuttings, b is 1, when the scrap steel raw material type is thin plate crushed material: b is 0.5;

[0082] (4) When the amount of scrap steel raw material stored in the scrap steel bucket 14 is less than the weight value m7 of the scrap steel raw material to be added to the lower hopper 41 or reaches its lower limit, the scrap steel crusher is turned on and the qualified scrap steel to be crushed is added from the feeding port 12. After the scrap steel is crushed, it enters the scrap steel bucket 14 from the lower hopper 13; when the crushed scrap steel raw material in the scrap steel bucket 14 reaches a preset weight by the scrap steel bucket weighing device 18, first stop adding scrap steel from the feeding port 12; then stop the scrap steel crusher 11 to complete the loading work of the scrap steel bucket 14.

[0083] By repeating the above steps, each subsystem is interlocked and controlled to accurately control the weight of the preheated crushed scrap steel raw materials added to the molten iron ladle, avoiding the phenomenon that too much crushed scrap steel is added to cause the molten iron temperature to be too low or too little crushed scrap steel is added to cause the molten iron temperature to be too high, thereby increasing the converter scrap steel ratio and achieving cost reduction and efficiency improvement for steel companies. The relevant data statistics during the implementation of the system are shown in Table 1.

[0084] Table 1 Statistics of relevant data during the implementation of a method for adding scrap steel to a hot metal ladle

[0085]

[0086] It can be seen from Table 1 that after Examples 4 to 8 adopt the method of the present application, the initial average temperature of the molten iron is 1332.8°C, the average amount of preheated crushed scrap steel added is 1788kg, and the average temperature of the molten iron entering the furnace is 1296.4°C, which meets the process requirement of converter steelmaking for the molten iron temperature entering the furnace ≥1250°C. The average scrap steel ratio is 21.22%, and the implementation effect is good.

[0087] In Comparative Examples 1 and 2 which do not adopt the method of the present application, in Comparative Example 1, the molten iron temperature is 1326°C, 506 kg of preheated and crushed scrap steel is added, and the molten iron temperature entering the furnace is 1316°C. The amount of preheated and crushed scrap steel added is relatively small, the molten iron temperature entering the furnace is relatively abundant, and the scrap steel ratio of the converter is relatively low, only 18.37%; in Comparative Example 2, the molten iron temperature is 1336°C, 4531 kg of preheated and crushed scrap steel is added, the molten iron temperature entering the furnace is 1243°C, and the scrap steel ratio reaches 25.32%. In Comparative Example 2, the amount of preheated and crushed scrap steel added is relatively large, resulting in a low molten iron temperature entering the furnace, which cannot meet the process requirement of converter steelmaking for a molten iron temperature of ≥1250°C, and will have a certain degree of adverse effect on converter blowing.

Claims

1. A scrap steel adding system for a ladle, characterized in that: include: A scrap steel crushing system (1) comprises a scrap steel crusher (11) and a scrap steel bucket (14) which are arranged in correspondence with each other, wherein a scrap steel bucket weighing device (18) is arranged outside the scrap steel bucket (14), and a vibrating feeder (15), a weighing device (16) and a gate valve (17) are arranged at the bottom of the scrap steel bucket in sequence; Feeding system (2); Flue gas recovery system (3); and A material preheating weighing system (4), comprising an upper hopper (41), an upper hopper weighing device (42) disposed on the upper hopper (41), a high-position vibrating feeder (43) disposed at the bottom end of the upper hopper (41), a scrap steel preheating system (44) disposed below the high-position vibrating feeder (43), a low-position vibrating feeder (46) disposed at the bottom end of the scrap steel preheating system (44), and a low-position weighing device (42) disposed below the low-position vibrating feeder (46). The scrap steel preheating system (44) comprises a preheating bin (441) and an ignition and nozzle device (442) arranged on the preheating bin (441), a fuel gas medium pipeline (445) is connected to the ignition and nozzle device (442), and a high-position weighing device (45) is arranged at the bottom of the preheating bin (441); Wherein: the two ends of the feeding system (2) correspond to the gate valve (17) and the feeding hopper (41) respectively, and the scrap steel preheating system (44) is connected to the fume recovery system (3) through a pipeline.

2. A scrap steel adding system for a ladle according to claim 1, characterized in that: The scrap steel crusher (11) is a horizontal hammer crusher, and its upper and lower parts are respectively a feeding port (12) and a discharge port (13), and the scrap steel bucket (14) is correspondingly arranged below the discharge port (13).

3. A scrap steel adding system for a ladle according to claim 1, characterized in that: The feeding system (2) comprises a first chain plate conveyor consisting of a head wheel (22), a tail wheel (23) and a plurality of feeding chain plates (21); the head wheel (22) and the tail wheel (23) are provided with a driving motor and are movably connected via a chain; and the plurality of feeding chain plates (21) are evenly distributed on the chain.

4. A scrap steel adding system for a ladle according to claim 3, characterized in that: The feeding system (2) further comprises a second chain conveyor which is arranged horizontally and one side of which is located below the tail wheel (23) of the first chain conveyor. The second chain conveyor comprises two bidirectional driving wheels (25) connected by a chain. A driving motor is arranged on the bidirectional driving wheel (25). A plurality of unloading chain plates (24) are evenly distributed on the chain. The unloading preheating weighing system (4) is respectively arranged below the two bidirectional driving wheels (25) of the second chain conveyor.

5. A scrap steel adding system for a ladle according to claim 3 or 4, characterized in that: The first chain conveyor is arranged to be inclined upward at an acute angle; and an alloy lining plate is welded on the inner side of the lower hopper (41).

6. A scrap steel adding system for a ladle according to claim 5, characterized in that: The scrap steel preheating system (44) further comprises a feed port (444) arranged at the top of the preheating silo (441) and a fume recovery device (443) connected to the fume recovery system (3) via a pipeline, and the fuel gas medium pipeline (445) is respectively connected to a fuel gas source and a nitrogen source.

7. A method for adding scrap steel to a ladle, characterized in that: The method is carried out by a scrap steel adding system for a ladle according to any one of claims 1 to 6, wherein a molten iron vehicle (7) is arranged below the unloading preheating weighing system (4) and the molten iron ladle (6) is placed thereon, and the method comprises: Crushing of scrap steel raw materials: scrap steel is crushed into scrap steel raw materials by the scrap steel crusher (11) in the scrap steel crushing system (1) and then discharged into the scrap steel bucket (14); Scrap steel raw material feeding: the scrap steel raw material in the scrap steel hopper (14) is vibrated and discharged to the weighing device (16) by the vibrating feeder (15); the scrap steel raw material in the weighing device (16) is discharged to the feeding system (2) through the gate valve (17); the scrap steel raw material is transported by the feeding system (2) and discharged into the feeding hopper (41) of the feeding preheating weighing system (4); Preheating of scrap steel raw materials: the scrap steel raw materials in the upper hopper (41) are vibrated and discharged into the preheating bin (441) of the scrap steel preheating system (44) by the high-level vibrating feeder (43), and the fuel gas is delivered to the ignition and nozzle device (442) through the fuel gas medium channel (445). The ignition and nozzle device (442) is turned on to bake the scrap steel raw materials to a set temperature. During the baking process, the generated fume is sucked into the fume recovery system (3) for recovery and treatment through the fume recovery device (443); Feeding of scrap steel raw materials: the scrap steel raw materials preheated in the preheating bin (441) are vibrated and discharged to the low-level weighing device (47) through the low-level vibrating feeder (46), and the scrap steel raw materials are discharged into the molten iron ladle (6) through the lower gate valve (48) and the movable chute (49).

8. The method for adding scrap steel to a ladle according to claim 7, characterized in that: The method further comprises: The scrap steel raw material is scrap steel bar cuttings or thin plate crushing materials; The weight m1 of the preheated scrap steel raw material to be added to the ladle (6) is calculated based on the initial temperature of the molten iron to be added to the ladle (6), the temperature drop of the molten iron caused by the addition of the preheated scrap steel raw material, and the process requirement value of the converter for the temperature of the molten iron entering the furnace; based on the calculated m1 value, the low-level vibrating feeder (46) is controlled to vibrate and discharge the preheated scrap steel raw material in the preheating bin (441) to the low-level weighing device (47); when the weight of the scrap steel raw material weighed by the weighing device (47) reaches the m1 value, the scrap steel raw material is discharged into the ladle (6) through the lower gate valve (48) and the movable chute (49); wherein m1 satisfies the following empirical formula: m1=(T1-T2) / a Wherein, m1 is the weight of the preheated scrap steel raw material to be added to the ladle (6), kg; T1 is the initial temperature of the molten iron to be added to the ladle (6), °C; T2 is the process requirement of the converter for the temperature of the molten iron entering the furnace, °C; a is the temperature drop of the molten iron caused by adding 1 kg of preheated scrap steel raw material, and the value range is 0.015-0.020, °C; The storage amount of the scrap steel raw materials in the preheating bin (441), the lower hopper (41) and the scrap steel hopper (14) are respectively set with a lower limit value and a maximum material weight value that can be reached by their respective effective volumes, and the storage amount of the scrap steel raw materials in the preheating bin (441), the lower hopper (41) and the scrap steel hopper (14) is between their respective lower limit values ​​and the maximum material weight values; When the amount of scrap steel raw material stored in the preheating bin (441) is less than the weight m1 of the preheated scrap steel raw material to be added to the molten iron ladle (6) or reaches its lower limit, the weight m4 of the scrap steel raw material to be added to the preheating bin (441) is calculated based on the maximum weight m2 of the effective volume of the preheating bin (441), the weight coefficient b of the type of scrap steel raw material added, and the weight m3 of the remaining scrap steel raw material in the preheating bin (441); based on the calculated m4 value, the high-level vibrating feeder (43) is controlled to vibrate and feed the scrap steel raw material in the upper hopper (41) into the preheating bin (441) until the weight of the scrap steel raw material weighed by the high-level weighing device (45) reaches the m4 value; wherein m4 satisfies the following empirical formula: m4=(m2-m3)×b Wherein, m4 is the weight of the scrap steel raw material to be added to the preheating bin (441), kg; m2 is the maximum weight value that the effective volume of the preheating bin (441) can reach, kg; m3 is the weight value of the scrap steel raw material remaining in the preheating bin (441), kg; b is the weight coefficient of the scrap steel raw material type, when the scrap steel raw material type is scrap steel bar cuttings, b is 1, when the scrap steel raw material type is thin plate crushed material: b is 0.5; When the amount of scrap steel raw material stored in the lower hopper (41) is less than the weight m4 of the scrap steel raw material to be added to the preheating bin (441) or reaches its lower limit, the weight m7 of the scrap steel raw material to be added to the lower hopper (41) is calculated based on the maximum weight m5 of the effective volume of the lower hopper (41), the weight coefficient b of the type of scrap steel raw material added, and the weight m6 of the remaining scrap steel raw material in the lower hopper (41); the weight m7 of the scrap steel raw material to be added to the lower hopper (41) is calculated based on the calculated weight m8 of the scrap steel raw material to be added to the preheating bin (441). The vibrating feeder (15) is controlled to vibrate and discharge the scrap steel raw materials in the scrap steel hopper (14) into the weighing device (16) until the weight of the scrap steel raw materials weighed by the weighing device (16) reaches the value of m7, and the weighing device (16) stops and controls the gate valve (17) to discharge the scrap steel raw materials in the weighing device (16) into the feeding system (2), and the scrap steel raw materials are transported through the feeding system (2) and discharged into the feeding hopper (41); wherein m7 satisfies the following empirical formula: m7=(m5-m6)×b Wherein, m7 is the weight of the scrap steel raw material to be added to the lower hopper (41), kg; m5 is the maximum weight value that the effective volume of the lower hopper (41) can reach, kg; m6 is the weight value of the scrap steel raw material remaining in the lower hopper (41), kg; b is the weight coefficient of the scrap steel raw material type, when the scrap steel raw material type is scrap steel bar cuttings, b is 1, when the scrap steel raw material type is thin plate crushed material: b is 0.5; When the amount of scrap steel raw material stored in the scrap steel bucket (14) is less than the weight value m7 of the scrap steel raw material to be added to the lower hopper (41) or reaches its lower limit, the scrap steel crusher (11) is controlled to crush the scrap steel into scrap steel raw materials and then discharge the materials into the scrap steel bucket (14) until the scrap steel bucket weighing device (18) weighs the scrap steel raw material and stops when the weight reaches a preset weight value.

9. The method for adding scrap steel to a ladle according to claim 7, characterized in that: Before the fuel gas medium channel (442) transports the fuel gas, the fuel gas medium channel (445) is first purged with nitrogen.

10. The method for adding scrap steel to a ladle according to claim 7, characterized in that: The set temperature of the scrap steel raw material after baking is 400-600°C.

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