Method for increasing scrap steel addition amount by using blast furnace charging system

Abstract

The application belongs to the technical field of steel smelting, and particularly discloses a method for increasing the quantity of scrap steel added by using a blast furnace charging system, which comprises adding scrap steel into a blast furnace by using the charging system equipment of the blast furnace, and does not need to set a special scrap steel charging device for the adding process of the scrap steel, thereby saving cost; by adjusting the discharging sequence of sintered materials and scrap steel, the quantity of scrap steel added is increased when the scrap steel is added by using the blast furnace charging system on the basis of ensuring stable and smooth operation of the blast furnace, the consumption of sintered materials is correspondingly reduced, the emission of CO2 of the blast furnace is reduced, the blast furnace operation is more environmentally friendly and energy-saving; by optimizing the distribution matrix of sintered materials and scrap steel in the blast furnace and adjusting the arrangement of the material sequence in each batch of materials, the position positioning of the scrap steel on the plane of the blast furnace throat and the accurate distribution of each sintered material and scrap steel on the ring belt at the blast furnace throat are realized, the preparation for generating a stable gas flow during the blast furnace operation is made, and the stable production of the blast furnace is ensured.

Description

Technical Field

[0001] This invention relates to the field of iron and steel smelting technology, and specifically to a method for increasing the amount of scrap steel added using a blast furnace charging system. Background Technology

[0002] Scrap steel refers to steel waste that is not used as a product during the steelmaking process, as well as steel materials from discarded equipment and components. Scrap steel composed of steel is called scrap steel, and scrap iron composed of pig iron is called scrap iron; both are collectively referred to as scrap steel. Scrap steel is mainly divided into five categories: heavy, medium, small, mixed, and light scrap. Scrap steel is primarily used as an additive in long-process converters or as the main raw material in short-process electric arc furnaces.

[0003] The task of blast furnace ironmaking is to reduce iron ore or iron-containing raw materials into liquid pig iron at high temperatures using reducing agents (C, CO, H2, etc.). During the smelting process, the furnace charge, i.e., the sintering raw materials (sinter, pellets, flux, coke), is charged into the furnace in batches from the top of the furnace through the charging equipment of the blast furnace charging system in a predetermined proportion. The high-temperature hot air blown in from the tuyeres at the bottom of the blast furnace reacts with the coke to produce high-temperature reducing gas that rises and heats, reduces, melts, and slags the furnace charge, resulting in a series of physical and chemical changes. During the reduction process, a large amount of CO2 gas is produced in the blast furnace charge.

[0004] In the blast furnace smelting process, making greater use of scrap steel resources can effectively reduce energy consumption in smelting operations, while also reducing environmental risks in production, thus making a positive contribution to reducing iron consumption in steelmaking. Adding scrap steel to the blast furnace significantly improves scrap steel utilization. In the blast furnace, scrap steel only needs to be heated and melted into molten iron, without the need for reduction, which can greatly increase blast furnace capacity and production efficiency, while significantly reducing fuel consumption.

[0005] However, the amount of scrap steel added during existing blast furnace smelting is limited by the addition method and furnace conditions. Existing blast furnace systems use two methods for adding scrap steel: post-iron addition and pre-iron addition. Post-iron addition methods include adding scrap steel into the molten iron ladle or molten iron trough, while pre-iron addition involves adding scrap steel as part of the sinter batch. Adding scrap steel into the molten iron ladle and molten iron trough is limited by temperature, resulting in a maximum addition of only 50 kg / t. Adding scrap steel as part of the sinter batch is also limited by the amount of iron oxide scale and granulated steel used, resulting in a relatively small addition of only 40 kg / t.

[0006] The addition of scrap steel to the blast furnace can affect the stability of the gas flow inside the blast furnace. Adding large amounts of scrap steel in an attempt to reduce fuel consumption can easily lead to unstable blast furnace production and difficulties in operating the blast furnace, thus affecting the production of blast furnace smelting. Summary of the Invention

[0007] The purpose of this invention is to provide a method for increasing the amount of scrap steel added using a blast furnace charging system, in order to solve the problem that the limited amount of scrap steel added is due to the difficulty in the conventional blast furnace charging method and furnace conditions, which is not conducive to reducing energy consumption.

[0008] To achieve the above objectives, the basic solution provided by this invention is: a method for increasing the amount of scrap steel added using a blast furnace charging system, characterized by comprising the following steps:

[0009] S1: Prepare sintering raw materials, the sintering materials include scrap steel and sintering materials. The processed scrap steel is sorted by screening equipment to select scrap steel with qualified size.

[0010] S2: Transport the scrap steel and sintered materials that meet the charging dimensions to the ground material bins in the feeding area of ​​the blast furnace charging system;

[0011] S3: Arrange the sintered material and scrap steel according to the set discharge sequence, use the blast furnace charging system to feed them into the charging hopper, and load the sintered material and scrap steel into the furnace according to the designed material distribution matrix;

[0012] S4: Control the relevant smelting parameters according to reasonable smelting requirements and carry out smelting operations.

[0013] The principle of this invention is as follows: This invention uses the blast furnace's own charging system to charge scrap steel. By controlling the size of the scrap steel and loading it into the charging tank of the blast furnace charging system in the adjusted discharge order, the sintering material and scrap steel are arranged in a reasonable manner according to the optimized material distribution matrix. After the materials are added, the smelting operation is carried out according to the smelting requirements.

[0014] The present invention has the following beneficial effects:

[0015] (1) The present invention uses the blast furnace’s own charging system to add scrap steel into the blast furnace, eliminating the need for a special scrap steel charging device for the scrap steel addition process, thus saving costs.

[0016] (2) By adjusting the discharge sequence of sintering materials and scrap steel, while ensuring the stable operation of the blast furnace, the amount of scrap steel added by the blast furnace charging system is increased, the proportion of scrap steel added into the blast furnace is increased, and the amount of sintering materials used is reduced accordingly, thereby reducing the consumption of sintering materials.

[0017] (3) By optimizing the material distribution matrix of sintering materials and scrap steel in the blast furnace and adjusting the material sequence in each batch, the position of scrap steel in the blast furnace throat plane and the precise distribution of each sintering material and scrap steel in the annular zone at the throat were realized, which prepared for the generation of a stable gas flow during blast furnace operation and ensured stable blast furnace production.

[0018] (4) By increasing the amount of scrap steel added, the CO2 emissions of the blast furnace are reduced, making the operation of the blast furnace more environmentally friendly and energy-saving.

[0019] Option 2 is a preferred option of the basic option. In step S1, the size of the scrap steel is ≤100mm, and the amount of scrap steel with a size >100mm does not exceed 10% of the total amount of scrap steel. When the size of the scrap steel is >100mm, there is a possibility of material blockage during the feeding process. The staff needs to increase the clearing operation. Controlling the size of the scrap steel can minimize the occurrence of blockage.

[0020] Option 3, which is a preferred option of the basic option, involves sintering materials in step S1, including sintered ore, pellets, lump ore, and coke. By using sintered ore, pellets, lump ore, and coke separately added to the blast furnace, normal iron production operations of the blast furnace are ensured.

[0021] Option 4 is a preferred option of the basic option. In step S3, the material discharge sequence is 2 / 3 sintered ore → pellets → scrap steel → coke → lump ore → 1 / 3 sintered ore.

[0022] By adjusting the feeding sequence, it is possible to ensure that the subsequent feeding of scrap steel into the blast furnace does not affect the gas flow during production. By placing the scrap steel in a position away from the furnace wall and the center of the blast furnace, the added scrap steel will not affect the edge gas channel and the center gas channel respectively.

[0023] Option 5, which is a preferred option of the basic option, in step S4, the fabric matrix is: O 34 3 32 2 30 2 28 2 C34.5 3 32 2 29 2 26 2 16 1 According to the optimized material distribution matrix, 2 / 3 of the sinter is located at 34. 3 On the ring belt, the pellets are arranged at 32 2 On the ring belt, scrap steel, coke, and lump ore are all arranged at 30... 2 On the ring, 1 / 3 of the sinter is arranged at 28 2 On the ring belt, under the arrangement of this material distribution matrix, a stable gas flow can be formed in the blast furnace to ensure the smooth operation of the blast furnace. By adding a ring of coke, the heat loss caused by melting scrap steel is compensated, ensuring the stable and smooth operation of blast furnace production.

[0024] Option six, a preferred embodiment of option five, involves arranging 2 / 3 of the sintered ore in the fabric matrix at position 34. 3 On the ring belt, the pellets are arranged at 32 2 On the ring belt, scrap steel, coke, and lump ore are arranged at 30...2 On the ring, 1 / 3 of the sinter is arranged at 28 2 On the ring;

[0025] According to the discharge sequence of sintering materials and scrap steel, sintering raw materials are added to the blast furnace from the distributor and the charging chute, and are correspondingly arranged on the ring belt of the charging matrix. Reasonable charging helps the stable and smooth operation of blast furnace production.

[0026] Option 7, which is a preferred option of Option 5, refers to C 16. 1 The coke is located near the center of the blast furnace; by adding an extra ring of charging material, sufficient heat is ensured when the blast furnace is running smoothly.

[0027] Option 8, which is a preferred option of Option 2, uses a bar screen as the screening device in step S1. The bar screen has a screen aperture of 100mm. The scrap steel is screened by the bar screen to control the size of the scrap steel to below 100mm, so as to avoid jamming the feeding equipment during the process of adding scrap steel using the blast furnace feeding system. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the blast furnace charging system in the method for increasing the amount of scrap steel added using a blast furnace charging system according to the present invention;

[0029] Figure 2 This is a schematic diagram of the longitudinal section of the blast furnace throat when no scrap steel is added, in the method of increasing the amount of scrap steel added using the blast furnace charging system of the present invention;

[0030] Figure 3 This is a schematic diagram of the transverse cross section of the blast furnace throat when no scrap steel is added, in the method of increasing the amount of scrap steel added using the blast furnace charging system of the present invention;

[0031] Figure 4 This is a schematic diagram of the longitudinal section of the blast furnace throat during the addition of scrap steel in a method for increasing the amount of scrap steel added using a blast furnace charging system according to the present invention.

[0032] Figure 5 This is a schematic diagram of the transverse cross section of the blast furnace throat during the addition of scrap steel in a method for increasing the amount of scrap steel added using a blast furnace charging system, as described in this invention. Detailed Implementation

[0033] The present invention will be further described in detail below through specific embodiments:

[0034] Figure 1The reference numerals in the attached drawings include: 1. Ground material bin; 2. Feeder 1; 3. Conveying belt; 4. Discharge chute 1; 5. Discharge chute 2; 6. Bin; 7. Feeder 2; 8. Vibrating screen; 9. Weighing hopper; 10. Vibrator; 11. Sector gate; 12. Feeding belt; 13. Discharge chute 3; 14. Receiving hopper; 15. Baffle valve; 16. Upper sealing valve; 17. Material tank; 18. Material flow valve; 19. Lower sealing valve; 20. Distributor; 21. Distributor chute.

[0035] like Figures 1 to 5 As shown: A method for increasing the amount of scrap steel added using a blast furnace charging system, comprising the following steps:

[0036] S1: Prepare sintering raw materials, the sintering materials include scrap steel and sintering materials. The processed scrap steel is sorted by screening equipment to select scrap steel with qualified size.

[0037] S2: Transport the scrap steel and sintered materials that meet the feeding size to the ground material bins in the feeding area of ​​the blast furnace charging system respectively;

[0038] S3: Arrange the sintered material and scrap steel according to the set discharge sequence, use the blast furnace charging system to feed them into the charging hopper, and load the sintered material and scrap steel into the furnace according to the designed material distribution matrix;

[0039] S4: Control the relevant smelting parameters according to reasonable smelting requirements and carry out smelting operations.

[0040] The technical solution of the present invention will be described in more detail below through specific embodiments, but it is not intended to limit the scope of protection of the present invention.

[0041] Operators prepare sintering raw materials, which include scrap steel and sintering materials. The sintering materials include sintered ore, pellets, lump ore, and coke. The scrap steel needs to be checked twice, by the supplier and the plant staff, to strictly control the size of the scrap steel entering the furnace.

[0042] Table 1. Impact of scrap size on blast furnace charging system

[0043]

[0044] Table 1 shows the results obtained through repeated practical operation of the blast furnace charging system. It indicates that when the scrap size is >100mm, there is a possibility of material blockage during the feeding process, and the feeder will also experience blockage. Since the length and width of the discharge ends of the first and second blast furnace charging chutes are both 500mm, and the fan-shaped gate is 600mm long and 300mm wide, the most severe blockage occurs at the first and second chutes and the fan-shaped gate when the scrap size is unqualified. When the scrap size is >150mm and the proportion of scrap with a size >100mm in the total scrap is greater than 10%, the feeder, the first and second chutes, the fan-shaped gate, and the material flow valve will experience blockages at different frequencies.

[0045] Meanwhile, without affecting subsequent blast furnace charging operations, the charging time for a batch of sintering raw materials must not exceed 225 seconds. If no blockage occurs during the charging process, the charging time is about 180 seconds. If blockage or jamming occurs, it takes at least 90 seconds to deal with it. Therefore, the charging process of dealing with blockage and jamming requires at least 270 seconds. If it exceeds 225 seconds, it will affect the normal charging operation of the blast furnace, thus affecting the entire smelting cycle.

[0046] Therefore, the size of scrap steel entering the furnace should be controlled to be ≤100mm, and the amount of scrap steel with a size >100mm should be less than 10% of the total amount of scrap steel entering the furnace. Among them, the maximum size of scrap steel should be controlled to be ≤150mm.

[0047] The supplier pre-processes the scrap steel using a 100mm crusher. The processed scrap steel is then sorted by a screening device using a bar screen with 100mm mesh. The proportion of scrap steel larger than 100mm is determined by screening. After screening, the scrap steel is laid out on the ground for the first inspection and sorting, and scrap steel larger than approximately 150mm is promptly removed. The scrap steel is then transported to the plant and unloaded into the ground storage bin. Before being added to the ground storage bin, the scrap steel is inspected a second time by the ironmaking plant staff. If no large-sized scrap steel is found, it is ready to be added to the ground storage bin.

[0048] Sintered ore, pellets, lump ore, coke, and scrap steel are placed in the feeding area at the bottom of the silo, ready to be fed through the blast furnace's charging system. The conveying devices in the charging system, including ore conveyor belts and charging belts, are responsible for the main conveying of sintered ore, pellets, lump ore, coke, and scrap steel. When conveying scrap steel, the equipment control terminal starts the ore conveyor belt and the charging belt respectively, while simultaneously confirming that the permanent magnet separators above these four conveying devices are closed to prevent them from attracting the scrap steel. When conveying sintered ore, pellets, lump ore, and coke, the equipment control terminal starts the ore conveyor belt and the charging belt respectively, while simultaneously activating the permanent magnet separators above these four conveying devices to attract the scrap steel mixed in with the sintered ore, pellets, lump ore, and coke.

[0049] When transporting sinter, pellets, lump ore, coke, and scrap steel, they are mixed in a certain discharge sequence and then conveyed to the hopper of the feeding system. The discharge sequence is set as 2 / 3 sinter → pellets → scrap steel → coke → lump ore → 1 / 3 sinter.

[0050] Table 2. Discharge sequence and furnace parameters under varying scrap steel ratios.

[0051]

[0052] As shown in Table 2, when no scrap steel is added and the blast furnace is charged in the order of 1 / 2 sinter, pellets, 1 / 2 sinter, lump ore, and coke, the edge gas flow in the edge gas channel and the central gas flow in the central gas channel remain stable, the furnace operates smoothly, the gas utilization rate is 43%, and there is no gas flow in the pipeline. After adding scrap steel, the amount of scrap steel is continuously increased, and the scrap steel is added to the blast furnace in different charging orders. The edge gas flow in the edge gas channel and the central gas flow in the central gas channel will become weaker or stronger, respectively. The instability of the edge gas flow or the central gas flow will lead to difficulties in furnace operation.

[0053] When the scrap ratio is ≥150 kg / t, and the arrangement sequence is 2 / 3 sinter, pellets, scrap steel, coke, lump ore, and 1 / 3 sinter, the edge gas flow and central gas flow in the edge and central gas channels of the furnace can both reach a stable state again. The gas utilization rate is 43%, and there is no pipeline gas flow. Under this arrangement sequence, the amount of scrap steel added can be significantly increased, allowing the furnace conditions to remain stable, thus making the iron production more stable. In summary, a more optimal discharge sequence of 2 / 3 sinter → pellets → scrap steel → coke → lump ore → 1 / 3 sinter is formed.

[0054] In the process of increasing the amount of scrap steel added, the output of molten iron when scrap steel is added is significantly increased compared with the output when scrap steel is not added.

[0055] Table 3 Production parameters of sintered materials and scrap steel within ten days

[0056]

[0057] Table 3 shows that the theoretical average output of molten iron without adding scrap steel is 3531t, while the actual average output with adding scrap steel is 3955t. The average difference between the theoretical and actual output of molten iron without adding scrap steel is 424t, and the average consumption of scrap steel is 449t. From this, we can deduce that the average iron grade of the scrap steel is 94%, meaning that the scrap steel has a high iron grade. Adding 1t of scrap steel is approximately equivalent to an increase of 0.94t in the daily output of molten iron. Therefore, increasing the amount of scrap steel added helps to increase the output of molten iron.

[0058] After adjusting the discharge sequence of the sintering materials and scrap steel, they need to be added into the blast furnace according to a specific material distribution matrix. During blast furnace smelting, a stable gas channel needs to be formed inside the blast furnace. The gas channel is divided into two parts: the edge gas channel near the furnace wall, which is used to ensure that the furnace charge can descend at a uniform speed; and the central gas channel near the center of the blast furnace, which is used to ensure that the heat is highest at the center of the blast furnace, which helps to melt the ore from solid to liquid.

[0059] Sinter, pellets, lump ore, and scrap steel are all iron-containing raw materials. Their melting temperatures are in the following order: sinter > pellets > lump ore > scrap steel. Therefore, sinter, with its relatively higher melting temperature, is placed near the furnace wall and near the center of the blast furnace, respectively. Because of its higher melting temperature, sinter can form a thicker, more substantial layer vertically within the blast furnace than pellets, increasing the porosity of the layer and facilitating the flow of gas to form a stable gas passage. Simultaneously, sinter and scrap steel each possess their own natural angle of repose when added to the blast furnace.

[0060] Table 4. Angle of Repose Data for Sintered Materials and Scrap Steel

[0061] Material Category Sintered ore Pellet Ore Scrap steel Jiao Ding Block Ore Natural corner 31°-35° 24°-27° 40° 50° 40°-50°

[0062] Table 4 shows that the angle of repose of pellets is relatively small, ranging from 24° to 27°, and the pellets are round and easy to roll. The angle of repose of sinter is 31° to 35°, slightly larger than that of pellets. Placing pellets between the sinter at the furnace wall and the sinter at the center of the blast furnace can help position the pellets. Coke and lump ore have relatively large angles of repose, at 50° and 40°-50° respectively. Placing coke and lump ore relatively close to the center of the blast furnace helps guide the gas flow, making the gas flow as close as possible to the central gas channel. Since the melting temperature of scrap steel is the lowest among sinter, pellets, and lump ore, placing scrap steel away from the furnace wall and the center of the blast furnace will prevent the added scrap steel from affecting the edge gas channel and the central gas channel respectively.

[0063] When sintered materials are added to the blast furnace in the order of material discharge, the sintered materials will be distributed sequentially on the corresponding ring belts at the blast furnace throat, and the ring belts together form a material distribution matrix.

[0064] Table 5 Fabric matrix without scrap steel addition

[0065]

[0066] As shown in Table 5, without the addition of scrap steel, according to the fabric matrix O 34 3 32 2 30 2 28 2 C 34.5 3 32 2 29 2 26 3 Fabrication is carried out, in which sintered ore is at 34 3 On the ring zone, the pellet ore is at 32 2 On the ring, the block ore is at 30 2 On the ring, the pyridine is at 28 2 On the ring.

[0067] Table 6 Fabric matrix when adding scrap steel

[0068]

[0069] As shown in Table 6, at C 34.5 3 32 2 29 2 26 3 Add a C16 to the existing cloth matrix. 1 Fabric loops form a new fabric matrix O 34 3 32 2 30 2 28 2 C 34.53 32 2 29 2 26 2 16 1 In C16 1 A ring of coke is arranged on the annular belt. Sintered materials and scrap steel are added into the furnace according to the new feeding matrix, with 2 / 3 of the sintered ore arranged in zone 34. 3 On the ring (34) 3 The annular zone is located near the furnace wall), and the pellets are arranged in 32... 2 On the ring (32) 2 The circumference is only adjacent to 34 3 The ring belt (and near the furnace wall), scrap steel, coke, and lump ore are all arranged in a 30-meter radius. 2 On the ring (30) 2 The ring belt is located far from both the furnace wall and the center of the blast furnace, and 1 / 3 of the sinter is arranged in 28... 2 On the ring (28) 2 The annular zone is located near the center of the blast furnace.

[0070] Because the scrap steel is larger than the ore, the gas resistance in the upper blocky zone of the blast furnace is less than that in the ore. The gas velocity increases as it passes through the scrap steel. Therefore, the scrap steel is placed in the third ring zone (34) furthest from the furnace wall. 3 On the ring belt, the impact of adding scrap steel on the edge gas flow is reduced. At the same time, the melting of scrap steel requires the absorption of a large amount of heat. During the heat absorption process of scrap steel, the gas flow temperature in the central gas channel will decrease. The decrease in gas flow temperature will reduce the discharge rate of harmful elements.

[0071] At this point, an additional ring of coke is added to compensate for the heat loss caused by melting scrap steel, ensuring the stable and smooth operation of the blast furnace. As the amount of scrap steel added increases, the improved charging matrix can not only ensure the smooth operation of the blast furnace, but also reduce the use of other materials, thus saving energy.

[0072] Meanwhile, during the process of adding sintering materials and scrap steel to the blast furnace, the total batch weight of the furnace charge remains unchanged for each batch. The weight of sinter and pellets is adjusted according to the amount of scrap steel added and its weight changes. The total batch weight of the furnace charge is the sum of the weight of sinter, pellets, lump ore, and scrap steel in each batch.

[0073] Table 7. Standard Proportioning Table for Sintered Materials and Scrap Steel

[0074] Sintered ore proportion % Pellet ore ratio % Lump ore ratio % Scrap steel ratio % scrap steel ratio kg / t 70 20 10 0 0 69 20 8 3 50 68 18 8 6 100 67 17 8 8 150 65 16 8 11 200

[0075] As shown in Table 7, without the addition of scrap steel, sinter accounts for 70% of the total batch of ore, pellets account for 20%, and lump ore accounts for 10%. As the amount of scrap steel added gradually increases from 0 kg / t to 200 kg / t, the proportion of scrap steel in the total batch of ore gradually increases to 11%. To ensure normal production, the total batch weight of scrap steel and sintered materials must be kept constant. When the scrap steel proportion is 11%, the proportion of sintered materials is 65%, the proportion of pellets is 16%, and the proportion of lump ore is 8%. Compared with the case without the addition of scrap steel, the proportions of sintered materials, pellets, and lump ore in the total batch of ore have all decreased. Therefore, it can be further concluded that as the amount of scrap steel added increases, the amount of sintered materials used decreases accordingly, thus reducing energy consumption.

[0076] After the charging is completed, the blast furnace smelting stage begins. After the sintered materials and scrap steel are added to the blast furnace, the relevant smelting parameters are controlled according to reasonable smelting requirements, and smelting operations are carried out. During the smelting process, the ore-to-coke ratio is maintained at 4.0-4.2, the average coke particle size Ms ≥ 45mm, the central airflow temperature at the furnace top ≥ 500℃, the hot blast pressure is controlled at 350-360kPa, the blast temperature is 1130-1160℃, and the coal ratio is 110-130kg / t.

[0077] By adjusting the material feeding sequence, i.e. the material distribution matrix, and increasing the amount of scrap steel added, other sintering materials are saved accordingly. While the blast furnace operation remains stable, the output of molten iron increases.

[0078] Table 8 Comparison of key indicators for blast furnaces with and without scrap steel.

[0079] index No scrap steel added Add scrap steel Two ratios Daily production of molten iron (t / d) 3450 3860 410 <![CDATA[Utilization factor (t / m 3 ·d)]]> 3.19 3.57 0.38 Grade of furnace feed (%) 55.9 58.5 2.6 Main material consumption per unit (kg / t) 1688 1615 -73 Fuel ratio (kg / t) 572 519 -53 Coke ratio (kg / t) 482 429 -53 Process energy consumption (kgce / t) 431 391 -40 Cost of molten iron (RMB / ton) 2328 2333 5

[0080] As shown in Table 8, compared with smelting without adding scrap steel, the daily output of molten iron increased by 410 t / d, the grade of the blast furnace improved by 2.6%, and the unit consumption of main materials, fuel ratio, coke ratio, and process energy consumption decreased by 73 kg / t, 53 kg / t, 53 kg / t, and 40 kgce / t, respectively. The table shows that the main technical and economic indicators of blast furnaces have improved after adding scrap steel, especially the significant reduction in blast furnace fuel consumption, which lays a solid foundation for the green and low-carbon development of blast furnaces.

[0081] Production practice has proven that as the amount of scrap steel added increases, blast furnace operation becomes more environmentally friendly.

[0082] Table 9. Relationship between sintering material and scrap steel smelting process parameters and coke ratio.

[0083]

[0084] As shown in Table 9, a scrap steel ratio of 100 kg / t can reduce the coke ratio by an average of 33.2 kg / t. Therefore, the addition of scrap steel reduces the fuel consumption of the blast furnace, thereby reducing the CO2 emissions from the blast furnace and making production more environmentally friendly.

[0085] In summary, by utilizing the blast furnace's own charging system to feed scrap steel into the blast furnace, there is no need to set up dedicated charging equipment for scrap steel. During charging, sintered materials and scrap steel are added into the blast furnace, and the amount of scrap steel added is continuously increased. Even with the increase in the amount of scrap steel added, the smooth operation of the blast furnace can still be guaranteed according to the adjusted discharge sequence and charging matrix. This smelting process effectively reduces the consumption of ore, increases the output of molten iron, and makes the smelting process more green and environmentally friendly.

[0086] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for increasing the amount of scrap steel added using a blast furnace charging system, characterized in that, Includes the following steps: S1: Prepare sintering raw materials, which include scrap steel and sintering materials. The processed scrap steel is sorted by screening equipment to select scrap steel that meets the size requirements. The sintering materials include sintered ore, pellets, lump ore, and coke. S2: Transport the scrap steel and sintered materials that meet the charging dimensions to the ground material bins in the feeding area of ​​the blast furnace charging system; S3: Arrange the sintered material and scrap steel according to the set discharge sequence, use the blast furnace charging system to feed them into the charging hopper, and load the sintered material and scrap steel into the furnace according to the designed material distribution matrix; S4: Control the relevant smelting parameters and carry out smelting operations in accordance with reasonable smelting requirements; In step S3, the material discharge sequence is 2 / 3 sintered ore → pelletized ore → scrap steel → coke → lump ore → 1 / 3 sintered ore; the material distribution matrix in step S3 is: O 34 3 32 2 30 2 28 2 C 34.5 3 32 2 29 2 26 2 16 1 .

2. The method for increasing the amount of scrap steel added using a blast furnace charging system according to claim 1, characterized in that, In step S1, the size of the scrap steel is ≤100mm, and the amount of scrap steel with a size >100mm does not exceed 10% of the total amount of scrap steel.

3. The method for increasing the amount of scrap steel added using a blast furnace charging system according to claim 1, characterized in that, In the fabric matrix, 2 / 3 of the sinter is arranged in 34 3 On the ring belt, the pellets are arranged at 32 2 On the ring belt, scrap steel, coke, and lump ore are arranged at 30... 2 On the ring, 1 / 3 of the sinter is arranged at 28 2 On the ring.

4. The method for increasing the amount of scrap steel added using a blast furnace charging system according to claim 1, characterized in that, C 16 1 The coke is located near the center of the blast furnace.

5. A method for increasing the amount of scrap steel added using a blast furnace charging system according to claim 2, characterized in that, The screening device in step S1 is a bar screen with a screen aperture of 100mm.

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