A converter smelting method based on hot-pressed iron blocks

Abstract

This application relates to the field of converter smelting technology, and more particularly to a converter smelting method based on hot-pressed iron blocks. The converter smelting method includes the following steps: desulfurizing and transferring the converter to obtain a tapping converter; determining the oxygen consumption based on the loading capacity of the tapping converter; determining the gradient preset oxygen blowing ratio and the blowing oxygen ratio based on the oxygen consumption and the smelting cycle of the tapping converter; adding limestone and a first hot-pressed iron block to the tapping converter as pre-feeding material to obtain pre-molten iron; under the gradient preset oxygen blowing ratio conditions, adding batch materials to the pre-molten iron in batches for slag pressing to obtain slag-containing molten iron; under the blowing oxygen ratio conditions, adding process materials to the slag-containing molten iron for blowing treatment to obtain tapped steel; the process materials include a second hot-pressed iron block; and tapping the tapped steel to complete the converter smelting process. This converter smelting method improves the stability of the converter blowing process through raw material substitution and adaptation, precise process control, process risk prevention and control, and equipment and cost synergy.

Description

Technical Field

[0001] This application relates to the field of converter smelting technology, and in particular to a converter smelting method based on hot-pressed iron blocks. Background Technology

[0002] In modern steel production processes, the continuity and stability of the converter steelmaking process are crucial to the overall production efficiency of steel. The converter smelting process typically uses overhead cranes to transport scrap steel hoppers. Because these cranes frequently need to be stopped for maintenance, this can prevent the hoppers from being properly refilled with scrap steel. However, converter smelting cannot be stopped, and the crane shutdowns for maintenance disrupt the smooth operation of the converter smelting process.

[0003] To address this issue, the traditional method involves using a full-iron smelting process, adding molten iron or iron-containing materials (scrap iron or scrap steel) during crane shutdown and maintenance. However, full-iron smelting suffers from unstable blowing, resulting in large amounts of flue gas, short service life of oxygen lances, and high consumption of molten iron. Summary of the Invention

[0004] This application provides a converter smelting method based on hot-pressed iron blocks to solve the following technical problem: how to improve the stability of the blowing process in the whole hot metal smelting process.

[0005] In a first aspect, embodiments of this application provide a converter smelting method based on hot-pressed iron blocks, the converter smelting method comprising the following steps: The converter is desulfurized and then transferred to a separate container to obtain an iron tapping converter; The oxygen consumption is determined based on the loading capacity of the blast furnace. Based on the oxygen consumption and the smelting cycle of the tapping converter, the gradient preset oxygen blowing ratio and the smelting oxygen blowing ratio are determined. Limestone and the first hot-pressed iron block are added to the tapping converter for pre-feeding to adjust the slag system of the tapping converter and obtain pre-molten iron. Under the preset oxygen blowing ratio, batch materials are added to the pre-melted iron in batches for slag pressing to form slag in the pre-melting converter, thereby obtaining slag-containing molten iron; wherein, the batch materials include quicklime, lightly burned iron, and batch hot-pressed iron blocks; Under the specified blowing oxygen ratio conditions, the process material is added to the slag-containing molten iron for blowing treatment to obtain molten steel; wherein, the process material includes a second hot-pressed iron block; The molten steel is tapped to complete the converter smelting process.

[0006] Optionally, under the preset oxygen blowing ratio, batches of material are added to the pre-melted iron in stages for slag pressing to form slag in the pre-melting converter, thereby obtaining slag-containing molten iron, including the following steps: Under the first oxygen blowing ratio condition, the first batch of material is added to the pre-melted iron for the first slag pressing operation to form a small amount of slag on the surface of the pre-melted iron, thereby obtaining process iron; wherein, the first batch of material includes the first quicklime, the first lightly calcined iron and the first batch of hot-pressed iron blocks; Under the second oxygen blowing ratio conditions, two batches of materials are added to the molten iron in the process for a second slag pressing operation to adjust the composition and properties of the slag and obtain slag-containing molten iron; wherein, the two batches of materials include a second batch of quicklime, a second batch of lightly burned iron, and a second batch of hot-pressed iron blocks.

[0007] Optionally, the initial value of the first oxygen blowing ratio in the first slag pressing operation is ≥5%, and the final value of the first oxygen blowing ratio in the first slag pressing operation is <12%; and / or The initial value of the second oxygen blowing ratio in the second slag pressing operation is ≥12%, and the final value of the second oxygen blowing ratio in the second slag pressing operation is ≤16%.

[0008] Optionally, the volume content of carbon monoxide in the second slag pressing operation is <40%.

[0009] Optionally, the mass m1 of the first quicklime, the mass m2 of the first lightly burned iron, and the mass m3 of the first batch of hot-pressed iron blocks satisfy: m1:m2:m3 = (3.5 to 4.0):2:5; and / or The mass m4 of the second quicklime, the mass m5 of the second lightly burned iron, and the mass m6 of the second batch of hot-pressed iron blocks satisfy the following ratio: m4:m5:m6 = (3.0 to 4.0):1:5.

[0010] Optionally, the volume content of carbon monoxide in the blowing process is 40% to 60%.

[0011] Optionally, when the blowing oxygen ratio is <25%, the actual liquid level h1 of the slag-containing molten iron and the normal liquid level h0 of the slag-containing molten iron satisfy: h0-h1=8cm to 10cm; When the blowing oxygen ratio is ≥25%, the actual liquid level h1 of the slag-containing molten iron and the normal liquid level h0 of the slag-containing molten iron satisfy: h0=h1.

[0012] Optionally, if the actual time of the blowing process is less than or equal to 20% of the total time of the blowing process, the height of the blowing gun position in the blowing process shall be ≥200cm.

[0013] Optionally, in the pre-feeding process, the first hot-pressed iron block is added in batches, and a shaking operation is performed before and after each batch addition, with the shaking angle ranging from -40° to 60°.

[0014] Optionally, the mass m7 of the first hot-pressed iron block, the mass m8 of the batch hot-pressed iron block, and the mass m9 of the second hot-pressed iron block satisfy the following: m7:m8:m9=20:10:(0 to 10).

[0015] The technical solutions provided in this application have the following advantages compared with the prior art: This application provides a converter smelting method based on hot-pressed iron blocks. The method starts with the tapping converter after desulfurization and smelting. First, the oxygen consumption is determined based on the converter's loading capacity. Then, combining the oxygen consumption with the converter smelting cycle, the gradient preset oxygen blowing ratio for the charging stage and the blowing oxygen ratio for the blowing process are further clarified. Subsequently, through pre-charging of limestone and the first hot-pressed iron block, pre-molten iron containing an initial slag system is formed in the tapping converter. This initial slag system avoids uneven reaction caused by local raw material accumulation, providing a stable initial environment for the blowing process. Next, according to the gradient preset oxygen blowing ratio, batch materials containing quicklime, light-burned materials, and batches of hot-pressed iron blocks are added to the pre-molten iron in batches. The batch materials strengthen the initial slag system and suppress... The intense contact between oxygen and molten steel mitigates the high-temperature carbon-oxygen explosion reaction, fundamentally preventing converter splashing and smoke. Furthermore, by adding process material containing second hot-pressed iron blocks and slag-containing molten iron to the pre-melted iron according to the blowing oxygen ratio, a stable slag system can be formed during blowing. This slag system can coat the oxygen lance head, preventing molten steel from directly scouring the lance head, significantly reducing the probability of steel sticking to the oxygen lance, and improving the stability of the blowing process. Simultaneously, this converter smelting method completely replaces traditional scrap steel with first hot-pressed iron blocks, batch hot-pressed iron blocks, and second hot-pressed iron blocks throughout the entire process. This not only enhances the stability of the slag system within the converter and improves the blowing stability but also lowers the furnace temperature, mitigating the high-temperature carbon-oxygen explosion reaction, further improving the overall stability of the converter smelting process. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of a converter smelting method based on hot-pressed iron blocks is provided for an embodiment of this application; Figure 2 A detailed flow diagram of a converter smelting method based on hot-pressed iron blocks is provided for the embodiments of this application; Figure 3 A diagram showing the change in the position of the oxygen blowing lance during the blowing process provided in this application embodiment. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] The range descriptions used in this application, such as numerical ranges and proportional ranges, include all possible sub-ranges and single numerical values ​​within that range. For example, the range descriptions of "1 to 6" or "1~6" cover all sub-ranges (such as 1 to 3, 2 to 5, etc.) and single numbers (such as 1, 2, 3, 4, 5, 6) between 1 and 6. Unless otherwise specified, the terms "comprising" and others used herein mean "including but not limited to"; relational terms such as "first" and "second" are used only to distinguish different entities or operations and do not imply an actual order or relationship; "and / or" indicates that multiple situations can exist individually or simultaneously; expressions such as "at least one," "multiple," and "at least one" refer to any combination of the corresponding objects, including combinations of single or multiple objects. The proportional relationships involved in this document, such as mass ratios and molar ratios, should be understood as the correspondence between the first and second terms of a proportional formula, according to the order of description. The raw materials, reagents, instruments, and equipment used herein can all be obtained by purchasing from the market or by existing methods.

[0021] It should be noted that the following problems exist in the all-hot metal smelting process: (1) The reaction inside the converter is violent during the all-hot metal smelting process, and explosive carbon-oxygen reaction is likely to occur, which will result in a large amount of flue gas being generated during the blowing process of converter smelting. The dust concentration in these flue gas can reach 2 to 3 times that of the normal converter smelting process, which seriously exceeds the environmental control standards; (2) The converter smelting process forms a high-temperature and high-oxidation smelting environment, which causes the head of the oxygen lance to form nodules quickly, and the thickness of the nodules can increase by 30 mm to 50 mm in a single converter smelting cycle, which will significantly reduce the service life of the oxygen lance; (3) The all-hot metal smelting process lacks the cooling capacity of scrap steel, which makes the iron consumption in the all-hot metal smelting process remain high. Compared with the conventional converter smelting process, the iron consumption per ton of steel is as high as 70 kg to 80 kg.

[0022] The current steelmaking process using hot-pressed iron ore powder briquettes has lower iron consumption. The core process involves pressing hot-pressed iron ore powder, generated during the steelmaking raw material production process, into hot-pressed iron ore powder briquettes, which are then directly used in steelmaking. The steelmaking process using hot-pressed iron ore powder briquettes is similar to conventional steelmaking, consisting of a furnace charging step and a steelmaking step. The furnace charging step involves evenly spreading the hot-pressed iron ore powder briquettes in one or more layers in a trough. Pig iron or scrap steel can be added to the spread hot-pressed iron ore powder briquettes to form a mixture. The hot-pressed iron ore powder briquettes or the mixture are then added to the steelmaking furnace for steelmaking. Using a mixture increases the yield of molten steel obtained from converter smelting.

[0023] Therefore, if the steelmaking process of hot-pressed iron briquettes can replace the traditional all-hot iron smelting process, the defects of the all-hot iron smelting process can be solved. However, the feeding process of hot-pressed iron briquettes is complicated and the amount of hot-pressed iron briquettes added is limited, which has a limited impact on the stability of the steelmaking process of hot-pressed iron briquettes and the raw material consumption per ton of steel.

[0024] In view of the above-mentioned deficiencies, the embodiments of this application provide the following technical solutions: Figure 1 An exemplary schematic diagram of a converter smelting method based on hot-pressed iron blocks provided in an embodiment of this application is shown. like Figure 1 As shown in the embodiment of this application, a converter smelting method based on hot-pressed iron blocks is provided. The converter smelting method includes the following steps: S1. Desulfurize the converter and transfer it to a separate container to obtain an iron tapping converter; S2. Determine the oxygen consumption based on the loading capacity of the tapping converter; S3. Determine the gradient preset oxygen blowing ratio and the smelting oxygen blowing ratio based on the oxygen consumption and the smelting cycle of the tapping converter; S4. Limestone and the first hot-pressed iron block are added to the tapping converter for pre-feeding to adjust the slag system of the tapping converter and obtain pre-molten iron; S5. Under the preset oxygen blowing ratio, batch materials are added to the pre-melted iron in batches for slag pressing operation to form slag in the pre-melting converter and obtain slag-containing iron; wherein, the batch materials include quicklime, lightly burned iron and batch hot-pressed iron blocks; S6. Under the specified blowing oxygen ratio conditions, the process material is added to the slag-containing molten iron for blowing treatment to obtain molten steel; wherein, the process material includes a second hot-pressed iron block; S7. The molten steel is tapped to complete the converter smelting.

[0025] It should be noted that the desulfurization tumbler can use high-age ladles for tapping. The tapping volume of the desulfurization tumbler can be strictly controlled according to >230t, based on the upper limit that the desulfurization station can handle. This can not only give full play to the role of the desulfurization station, but also ensure the amount of hot-pressed iron blocks to be charged into the converter later.

[0026] It should be noted that the oxygen consumption is determined based on the loading capacity of the tapping converter. Specifically, taking a converter with a total loading capacity of 248t to 255t as an example, and using a tapping converter loading capacity of 215t to 225t as a benchmark, the oxygen consumption needs to be increased by 200m³ compared to the oxygen consumption required for traditional all-hot metal smelting. 3 up to 300m 3 By precisely controlling oxygen consumption, it is possible to ensure that the molten iron reacts fully with the hot-pressed iron blocks and other raw materials, thus achieving precise control over the composition and temperature of the molten steel.

[0027] It should be noted that the oxygen blowing ratio refers to the volume ratio of the oxygen consumed by the oxygen lance in the molten iron introduced into the converter to the total oxygen consumption.

[0028] It should be noted that the oxygen blowing ratio increases by 1% within 10 seconds.

[0029] It should be noted that during the pre-charging stage, limestone is first added to the bottom of the converter, followed by the addition of the first batch of hot-pressed iron blocks in three batches. Furthermore, the amount of limestone added can vary from 3 to 5 tons depending on the silicon content of the molten iron in the converter.

[0030] It should be noted that during the feeding process of the process material, the second hot-pressed iron block can be added in batches, with each batch containing 1 ton of the second hot-pressed iron block. In addition to the second hot-pressed iron block, lightly calcined and / or quicklime can also be added to the process material.

[0031] It should be noted that during the tapping process, careful observation is needed to detect the presence of viscous scrap steel inside the converter. For heats without post-blowing, slag should be promptly removed and sent for testing during tapping to closely monitor the final composition of the molten steel. These measures help identify quality issues during the converter tapping stage and ensure that the quality of the molten steel meets the required standards.

[0032] It should be noted that in actual production operations, it was found that the addition of the first hot-pressed iron block, the batch of hot-pressed iron blocks, and the second hot-pressed iron block has a key characteristic: for every 1 ton of hot-pressed iron block added, the consumption of limestone will increase by an additional 180 kg, and the temperature of the molten steel will decrease by 10°C.

[0033] It should be noted that, by mass fraction, the composition of the first hot-pressed iron block, the batch of hot-pressed iron blocks, and the second hot-pressed iron block meets the following requirements: FeO: 12.45%, C: 1.47%, SiO2: 1.82%, P: 0.034%, and S: 0.011%, with a magnetic iron (MFe) content of 70.73% and a total iron (TFe) content of 85.16%.

[0034] It should be noted that the converter smelting method based on hot-pressed iron blocks provided in this application addresses the core pain points of all-hot metal smelting, such as violent reactions, splashing and fumes, equipment blockage, and parameter fluctuations, through a comprehensive design that integrates raw material substitution and adaptation, precise process control, process risk prevention and control, and equipment and cost synergy. Ultimately, this significantly improves the stability of the converter blowing process. The specific mechanism is as follows: I. Replace scrap steel with hot-pressed iron blocks to solidify the foundation for continuous and stable production.

[0035] One of the core challenges in all-hotsink smelting is that the overhead crane cannot be charged with scrap steel during maintenance, resulting in a lack of cooling and regulating media in the converter and a high risk of reaction runaway. The converter smelting method provided in this application solves this problem through key design features, ensuring continuous production: 1. Raw material substitution and feeding adaptation: Hot-pressed iron blocks with stable composition (TFe≥85%, MFe≥70%) are selected as a complete substitute for scrap steel, and the total amount of hot-pressed iron blocks added is precisely controlled. Hot-pressed iron blocks are added in batches through the high-level hopper of the converter, without relying on scrap steel hoppers, completely avoiding the equipment limitations of overhead crane maintenance, and ensuring uninterrupted raw material supply. 2. Pre-charging Optimization of Slag System: In the pre-charging stage, limestone is first added as a base, followed by the addition of the first hot-pressed iron blocks in batches. The hot-pressed iron blocks are shaken before and after loading. This shaking operation allows the limestone to form the initial slag system in advance and promotes the even distribution of the first hot-pressed iron blocks within the converter, avoiding uneven reactions caused by localized raw material accumulation. This establishes a stable initial environment for subsequent blowing, reducing process fluctuations in converter smelting from the source.

[0036] Second, gradient oxygen blowing + batch slag pressing eliminates splashing and smoke.

[0037] In hot metal smelting, the lack of a cooling medium can easily lead to explosive carbon-oxygen reactions due to excessively high temperatures within the converter, resulting in splashing and smoke, severely compromising the stability of the blowing process. The converter smelting method provided in this application provides dual protection through gradient control of the oxygen blowing ratio and precise batch slag pressing. 1. Gradient preset oxygen blowing ratio to regulate reaction rhythm: Based on the smelting cycle of the converter (generally 40 min) and oxygen consumption, the oxygen blowing ratio is divided into multiple gradients such as 5%, 12%, 16%, 20% to 30% to avoid excessive oxygen being introduced at one time during the smelting of molten iron, which could lead to uncontrolled reaction. 2. Simultaneous slag pressing to stabilize the converter environment: The first batch of material is added at an oxygen blowing ratio of 5%, and the second batch is added at an oxygen blowing ratio of 12%, with the second batch added before the carbon monoxide volume content is less than 40%. The quicklime and light burning process rapidly thickens the slag, covering the surface of the molten steel in the converter, inhibiting intense contact between oxygen and molten steel. Simultaneously, the hot-pressed iron blocks have cooling properties, reducing the converter temperature and further mitigating the carbon-oxygen explosion reaction under high-temperature conditions, thus fundamentally preventing converter splashing and smoke emission. 3. Closed-loop control of CO content: During the blowing process, CO is strictly controlled at 50% to 60%, and when the CO in the converter approaches 60%, the feed is immediately added to press slag or the position of the oxygen blowing lance is finely adjusted to avoid the risk of excessive reaction in real time and ensure the stability of the converter's furnace mouth.

[0038] 3. Dynamic gun control and raw material matching reduce equipment clogging.

[0039] The high-temperature, high-oxidizing environment of molten iron smelting easily leads to oxygen lance sticking to steel, causing unplanned shutdowns and interrupting the blowing process. The converter smelting method provided in this application extends equipment life and ensures process continuity through dynamic lance position control and adaptation to the characteristics of hot-pressed iron blocks. 1. Low-flow variable lance position adaptation for converter smelting of hot-pressed iron blocks: From the start of blowing until the oxygen ratio reaches 20%, the oxygen lance position can be lowered to 200cm. Once the oxygen ratio exceeds 25%, the lance position can be restored. Subsequent adjustments can be made dynamically based on the CO content (lowering the lance by 100cm when CO content < 50%, and raising it by 100cm when CO content > 50%, with a maximum vertical adjustment of 400cm). This vertical adjustment method ensures the oxygen jet always contacts the molten steel at the optimal angle, preventing nodule formation at the lance head due to localized high temperatures. 2. Hot-pressed iron blocks alleviate high-temperature oxidation: The cooling effect of hot-pressed iron blocks can reduce the overall oxidation in the converter and reduce the corrosion of the oxygen lance by molten steel; at the same time, batch material and process material can form a stable slag system. This stable slag system can wrap the head of the oxygen lance, isolate it from direct scouring by molten steel, greatly reduce the probability of steel sticking to the oxygen lance, reduce equipment maintenance downtime, and ensure that the blowing process is not interrupted.

[0040] IV. Precise parameter control stabilizes the consumption of molten iron and the reaction process in the converter.

[0041] Because of the lack of scrap steel to regulate the process, molten iron consumption fluctuates greatly in traditional hot metal smelting, easily leading to deviations in steel composition and temperature from the target requirements, thus disrupting the stability of the blowing process. The converter smelting method provided in this application achieves dual stability in both hot metal consumption and the reaction process through precise control of all process parameters. 1. Precise matching of oxygen consumption and loading: Based on the total loading of the converter and the amount of iron charged in the tapping converter, the specific increase in oxygen consumption can be determined to ensure a stable reaction ratio between the hot-pressed iron block and the molten iron, and to avoid incomplete reaction or excessive oxidation due to insufficient or excessive content during the curing period.

[0042] 2. Continuous Energy Supplementation for Stable Process: After the oxygen blowing ratio reaches 16%, 1000 kg of hot-pressed iron blocks are added in each batch until a cumulative total of 30 to 40 tons is reached. Simultaneously, lightly calcined iron and limestone are used flexibly to assist in slag pressing operations. This slag pressing operation precisely replenishes materials according to the steel reaction progress and heat demand, avoiding slag thinning and weakened reaction due to insufficient raw materials, or excessive raw materials leading to excessively low temperatures and compositional fluctuations. 3. Dual control of endpoint and cycle time: The converter cycle time is controlled within 40 minutes, and material preparation is completed in advance; before the tapping operation, viscous scrap steel in the converter is checked, and slag samples are taken for testing to ensure that the carbon content and temperature at the end of the tapping operation meet the targets. The consumption of molten iron is stably controlled at a certain level to avoid repeated adjustments of process parameters caused by fluctuations in iron consumption, thus ensuring the consistency and stability of the blowing process.

[0043] In summary, the converter smelting method based on hot-pressed iron blocks provided in this application comprehensively improves the blowing stability of the entire hot metal smelting process from four dimensions: production continuity, environmental stability, equipment reliability, and cost controllability. This method completely solves the technical bottlenecks of traditional processes by addressing equipment limitations through raw material substitution, gradient process control of reaction rhythm, dynamic regulation and protection of equipment, and precise parameter stabilization of quality.

[0044] Figure 2 An exemplary schematic diagram of a detailed process for a converter smelting method based on hot-pressed iron blocks provided in an embodiment of this application is shown. In some alternative implementations, such as Figure 2 As shown, under the preset oxygen blowing ratio, batches of material are added to the pre-melted iron in batches for slag pressing to form slag in the pre-melting converter, resulting in slag-containing molten iron. The process includes the following steps: S501. Under the first oxygen blowing ratio condition, the first batch of material is added to the pre-melted iron for the first slag pressing operation to form a small amount of slag on the surface of the pre-melted iron to obtain process iron; wherein, the first batch of material includes the first quicklime, the first lightly burned iron and the first batch of hot-pressed iron blocks; S502. Under the second oxygen blowing ratio condition, two batches of materials are added to the molten iron in the process for a second slag pressing operation to adjust the composition and properties of the slag and obtain slag-containing molten iron; wherein, the two batches of materials include a second batch of quicklime, a second batch of lightly burned iron and a second batch of hot-pressed iron blocks.

[0045] In these embodiments, the batch material is divided into a first batch and a second batch according to different oxygen blowing ratios. The first batch of material undergoes a first slag pressing operation, which can rapidly form suitable slag in the converter by using the first batch of material, which includes the first quicklime, the first light calcined material, and the first batch of hot-pressed iron blocks. This slag will cover the surface of the molten steel in the converter, reducing heat loss and gas absorption by the molten steel. At the same time, this slag will participate in the steelmaking reaction and promote the removal of impurities in the molten steel. In addition, the second batch of material undergoes a second slag pressing operation. The second batch of material, which includes the second quicklime, the second light calcined material, and the second batch of hot-pressed iron blocks, can adjust the slag composition and properties, enhance the slag pressing effect of the second slag pressing operation, and ensure the stable progress of the blowing process.

[0046] In some optional embodiments, the initial value of the first oxygen blowing ratio in the first slag pressing operation is ≥5%, and the final value of the first oxygen blowing ratio in the first slag pressing operation is <12%; and / or The initial value of the second oxygen blowing ratio in the second slag pressing operation is ≥12%, and the final value of the second oxygen blowing ratio in the second slag pressing operation is ≤16%.

[0047] In these embodiments, the first slag pressing operation, with an initial oxygen blowing ratio ≥5% and a final oxygen blowing ratio <12%, allows the first batch of material to rapidly form suitable slag in the converter. This slag reduces heat loss and steel absorption, participates in the steelmaking reaction, and promotes the removal of impurities from the molten steel. Furthermore, the second slag pressing operation, with an initial oxygen blowing ratio ≥12% and a final oxygen blowing ratio ≤16%, allows the second batch of material to effectively adjust the composition and properties of the slag formed in the first slag pressing operation, ensuring the stable progress of the blowing process.

[0048] In some alternative embodiments, the volume content of carbon monoxide in the second slag pressing operation is <40%.

[0049] In these embodiments, the second slag pressing operation with a carbon monoxide volume content of <40% can be at a low CO level, avoiding the risk of excessive reaction, ensuring that the converter is in a stable, safe and efficient state during the blowing process, and effectively preventing production accidents.

[0050] It should be noted that CO content, as a key indicator in the blowing process, can directly reflect the reaction progress and the condition inside the furnace. The level of CO content is related to the intensity of the reaction inside the converter; therefore, controlling the CO content can prevent the reaction inside the converter from becoming too intense.

[0051] The volumetric carbon monoxide content of the second slag pressing operation can be 5%, 10%, 15%, 20%, 25%, 30%, 35%, or 40%.

[0052] In some optional embodiments, the mass m1 of the first quicklime, the mass m2 of the first lightly burned lime, and the mass m3 of the first batch of hot-pressed iron blocks satisfy: m1:m2:m3 = (3.5 to 4.0):2:5; and / or The mass m4 of the second quicklime, the mass m5 of the second lightly burned iron, and the mass m6 of the second batch of hot-pressed iron blocks satisfy the following ratio: m4:m5:m6 = (3.0 to 4.0):1:5.

[0053] In these embodiments, the first batch of quicklime, the first batch of lightly calcined iron, and the first batch of hot-pressed iron blocks in a mass ratio of (3.5 to 4.0):2:5 allow the first batch of material to rapidly form suitable slag in the converter. This slag reduces heat loss and gas absorption by the molten steel, participates in the steelmaking reaction, and promotes the removal of impurities from the molten steel. Furthermore, the second batch of quicklime, the second batch of lightly calcined iron, and the second batch of hot-pressed iron blocks in a mass ratio of (3.0 to 4.0):1:5 allow the second batch of material to effectively adjust the composition and properties of the slag formed during the first pressing operation, ensuring the stable progress of the blowing process.

[0054] The mass m1 of the first quicklime can be 3.5, 3.6, 3.57, 3.8, 3.9 or 4.0.

[0055] The mass m4 of the second quicklime can be 3.0, 3.1, 3.2, 3.3, 3.4, 3.5 or 4.0.

[0056] In some alternative embodiments, the carbon monoxide volume content of the blowing treatment is 40% to 60%.

[0057] In these embodiments, a blowing process with a carbon monoxide volume content of 40% to 60% can avoid vigorous reactions during the blowing process and ensure the stable progress of the blowing process.

[0058] The volumetric carbon monoxide content of the blowing process can be 40%, 41%, 42%, 43%, 44%, 45%, 50%, 55%, or 60%.

[0059] In some optional embodiments, when the blowing oxygen ratio is <25%, the actual liquid level h1 of the slag-containing molten iron and the normal liquid level h0 of the slag-containing molten iron satisfy: h0-h1=8cm to 10cm; When the blowing oxygen ratio is ≥25%, the actual liquid level h1 of the slag-containing molten iron and the normal liquid level h0 of the slag-containing molten iron satisfy: h0=h1.

[0060] In these embodiments, when the oxygen blowing ratio is <25%, the actual liquid level h1 and the normal liquid level h0 of the slag-containing molten iron satisfy: h0-h1=8cm to 10cm. When the oxygen blowing ratio is ≥25%, the actual liquid level h1 and the normal liquid level h0 of the slag-containing molten iron satisfy: h0=h1. The liquid level height of the slag-containing molten iron in the converter can be dynamically adjusted according to different oxygen blowing ratios, which can optimize the contact area between oxygen and molten steel, improve reaction efficiency, and reduce the occurrence of abnormal situations such as splashing.

[0061] The actual liquid level h1 of the slag-containing molten iron and the normal liquid level h0 of the slag-containing molten iron can satisfy h0-h1=8cm, 8.5cm, 9.0cm, 9.5cm or 10.0cm.

[0062] It should be noted that the normal liquid level h0 of this slag-containing molten iron is generally 950cm to 1000cm.

[0063] In some optional embodiments, when the actual time of the blowing process is less than or equal to 20% of the total time of the blowing process, the height of the blowing gun position in the blowing process is ≥200cm.

[0064] In these embodiments, when the blowing process has actually progressed to 25%, the blowing lance position height is maintained at 200cm. This allows for precise control of the oxygen lance position, ensuring that the oxygen jet enters the molten steel in the best possible condition, promoting uniform reaction, and improving steelmaking quality and efficiency.

[0065] It should be noted that the later stages of this refining process can be: like Figure 3 As shown, after the oxygen blowing ratio reaches 25%, the oxygen blowing lance position is restored to the standard level (220cm). Then, the oxygen blowing lance position is adjusted according to the CO content. If the CO content is <50%, the oxygen blowing lance position is lowered by 100mm. At this time, the CO content in the converter continues to decrease, and the oxygen blowing lance position is lowered by another 100mm. If the CO content is >50%, the oxygen blowing lance position is raised by 100mm. If the CO content continues to rise, the oxygen blowing lance position is raised again. The oxygen blowing lance position can be raised by a maximum of 400cm. At the same time, limestone and lightly calcined auxiliary hot-pressed iron blocks are used to simultaneously perform slag pressing operations during the blowing process to avoid slag splashing during the blowing process.

[0066] In some alternative embodiments, during the pre-feeding, the first hot-pressed iron block is added in batches, and a shaking operation is performed before and after the batch addition, with the shaking angle ranging from -40° to 60°.

[0067] In these embodiments, the first hot-pressed iron block is added to the tapping converter in batches, and the converter is shaken at an angle of -40° to 60° before and after the batch addition. This can promote the uniform distribution of limestone and the first hot-pressed iron block in the tapping converter, thereby adjusting the slag system in the converter in advance, creating favorable conditions for subsequent reactions, and improving the sufficiency of the reaction.

[0068] The angle of the shaking operation can be -40°, -30°, -20°, -10°, 0°, 10°, 20°, 30°, 40°, 50° or 60°.

[0069] In some optional embodiments, the mass m7 of the first hot-pressed iron block, the mass m8 of the batch of hot-pressed iron blocks, and the mass m9 of the second hot-pressed iron block satisfy: m7:m8:m9=20:10:(0 to 10).

[0070] In these embodiments, the first hot-pressed iron block, the batch hot-pressed iron block, and the second hot-pressed iron block with a mass ratio of 20:10:(0 to 10) can be added in batches, which is beneficial to the stable formation of slag in the converter, so as to ensure the stable reaction ratio between the hot-pressed iron block and the molten iron, and avoid incomplete reaction or excessive oxidation caused by insufficient or excessive content during the curing period.

[0071] The mass m9 of the second hot-pressed iron block can be 0, 1, 2, 3, 4, 5 or 10.

[0072] The present application is further illustrated below with reference to specific embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national / industry standards; if there is no corresponding national / industry standard, they are performed according to general international standards, conventional conditions, or conditions recommended by the manufacturer.

[0073] Example 1 During overhead crane shutdown and maintenance, taking a converter in a certain heat as an example, this converter uses a low-flow, variable-lance blowing model. The total load of this converter is planned to be controlled between 248t and 255t.

[0074] like Figure 2 As shown, a converter smelting method based on hot-pressed iron blocks includes the following steps: S1. The converter is desulfurized and the iron is transferred to the slag heap. The iron output from the slag heap is 230.3t, and the desulfurization is KR desulfurization, resulting in an iron-tapping converter. S2. Based on the loading capacity of the tapping converter, it is determined that the oxygen consumption needs to be increased by 200m³. 3 up to 300m 3 The total oxygen consumption was 10993 m³. 3 .

[0075] S3. Based on the oxygen consumption and the smelting cycle of the tapping converter (48 min), determine the gradient preset oxygen blowing ratio and the smelting oxygen blowing ratio. S4. Add 3013 kg of limestone and 20 t of the first hot-pressed iron block to the tapping converter for pre-feeding (the first hot-pressed iron block is added in batches) to adjust the slag system of the tapping converter and obtain 223.46 t of pre-melted iron. S501. Under the first oxygen blowing ratio condition, the first batch of material is added to the pre-melted iron for the first slag pressing operation to form a small amount of slag on the surface of the pre-melted iron to obtain process iron; wherein, the first batch of material includes the first quicklime, the first light calcined iron and the first batch of hot-pressed iron blocks; S502. Under the second oxygen blowing ratio, two batches of materials are added to the process hot iron for the second slag pressing operation to adjust the composition and properties of the slag, resulting in 253.88t of slag-containing hot iron; wherein, the two batches of materials include the second batch of quicklime, the second batch of lightly calcined iron, and the second batch of hot-pressed iron blocks; S6. Under the blowing oxygen ratio conditions, the process material is added to the slag-containing molten iron for blowing treatment to obtain molten steel; wherein, the process material includes the second hot-pressed iron block and 828 kg of light calcined iron; S7. The molten steel is tapped to complete the converter smelting process, yielding 229.28t of molten steel.

[0076] The initial value of the first oxygen blowing ratio in the first slag pressing operation is 5%, and the final value of the first oxygen blowing ratio in the first slag pressing operation is 11.9% < 12%. The initial value of the second oxygen blowing ratio in the second slag pressing operation is 12%, and the final value of the second oxygen blowing ratio in the second slag pressing operation is 16%.

[0077] The volume content of carbon monoxide in the second slag pressing operation is <40%.

[0078] The mass m1 of the first batch of quicklime, the mass m2 of the first batch of lightly burned iron, and the mass m3 of the first batch of hot-pressed iron blocks satisfy the following: m1:m2:m3=4.0t:2t:5t; The mass m4 of the second batch of quicklime, the mass m5 of the second batch of lightly burned iron, and the mass m6 of the second batch of hot-pressed iron blocks satisfy the following condition: m4:m5:m6 = 3.193t:1t:5t.

[0079] The volume content of carbon monoxide in the blowing process is 40% to 60%.

[0080] When the oxygen blowing ratio is <25%, the actual liquid level h1 of slag-containing molten iron and the normal liquid level h0 of slag-containing molten iron satisfy: h0-h1=8cm to 10cm; When the oxygen blowing ratio is ≥25%, the actual liquid level h1 of slag-containing molten iron and the normal liquid level h0 of slag-containing molten iron satisfy: h0=h1.

[0081] When the actual time of the blowing process is less than or equal to 20% of the total blowing time, the height of the blowing gun position in the blowing process is 200cm.

[0082] During the pre-feeding process, the first hot-pressed iron block is added in batches, and a shaking operation is performed before and after each batch is added. The shaking angle is between -40° and 60°, and the converter rotates once during the shaking operation.

[0083] The mass m7 of the first hot-pressed iron block, the mass m8 of the batch of hot-pressed iron blocks, and the mass m9 of the second hot-pressed iron block satisfy the following condition: m7:m8:m9=20t:10t:0.42t.

[0084] Example 2 Compared to Example 1, the differences in this example are as follows, while the rest are the same: The amount of iron discharged from the hopper was 230.3t.

[0085] The total oxygen consumption was 11390 m³. 3 .

[0086] During the pre-feeding process, the amount of limestone added was 4016 kg, and the amount of the first hot-pressed iron block added was 20 t.

[0087] The mass of the pre-melted molten iron is 218.37t.

[0088] The mass of molten iron containing slag was 251.94t.

[0089] The mass of the molten steel was 227.62 tons.

[0090] The process materials include a second hot-pressed iron block, 158 kg of quicklime, and 1064 kg of lightly calcined iron.

[0091] The mass m1 of the first batch of quicklime, the mass m2 of the first batch of lightly burned iron, and the mass m3 of the first batch of hot-pressed iron blocks satisfy the following: m1:m2:m3=4.0t:2t:5t; The mass m4 of the second batch of quicklime, the mass m5 of the second batch of lightly burned iron, and the mass m6 of the second batch of hot-pressed iron blocks satisfy the following formula: m4:m5:m6=3.658t:1t:5t.

[0092] The mass m7 of the first hot-pressed iron block, the mass m8 of the batch of hot-pressed iron blocks, and the mass m9 of the second hot-pressed iron block satisfy the following condition: m7:m8:m9=20t:10t:8.57t.

[0093] Example 3 Compared to Example 1, the differences in this example are as follows, while the rest are the same: The mass m4 of the second batch of quicklime, the mass m5 of the second batch of lightly burned iron, and the mass m6 of the second batch of hot-pressed iron blocks satisfy the following condition: m4:m5:m6 = 3.5t:1t:5t.

[0094] The mass m7 of the first hot-pressed iron block, the mass m8 of the batch of hot-pressed iron blocks, and the mass m9 of the second hot-pressed iron block satisfy the following condition: m7:m8:m9 = 20t:10t:5.78t.

[0095] Comparative Example 1 Compared to Example 1, the differences in this comparative example are as follows, while the rest are the same: Only the first hot-pressed iron block is added, and the amount of the first hot-pressed iron block added is 5t.

[0096] Comparative Example 2 Compared to Example 1, the differences in this comparative example are as follows, while the rest are the same: The batch of hot-pressed iron blocks is added all at once.

[0097] Relevant experimental and effect data: 1. The molten steel obtained from Examples 1 and 2 was collected and tested. The results showed that: According to the feeding, the expected target temperature of the molten steel in Example 1 was 1610℃ and the expected carbon content was 0.05%. However, the actual carbon content of the molten steel was 0.0339% and the actual temperature was 1620℃. This shows that the parameters of the molten steel met the expected targets.

[0098] In Example 2, the expected target temperature for the tapped molten steel was 1620°C and the expected carbon content was 0.04%, based on the feeding process. However, the actual carbon content of the tapped molten steel was 0.043%, and the actual temperature was 1611°C. This indicates that the parameters of the tapped molten steel met the expected targets.

[0099] 2. The mass of molten iron consumed, the number of unplanned oxygen lance positions, and the number of times smoke was emitted during the production process of each embodiment and comparative example were statistically analyzed. At the same time, the amount of hot-pressed iron blocks added was also statistically analyzed. The results are shown in Table 1.

[0100] Table 1. Changes in production process parameters for each embodiment and comparative example.

[0101] As shown in Table 1, the converter smelting method based on hot-pressed iron blocks provided in this application solves the core pain points of all-hot metal smelting, such as violent reactions, splashing and fumes, equipment blockage, and parameter fluctuations, through a comprehensive design that integrates raw material substitution and adaptation, precise process control, process risk prevention and control, and equipment and cost coordination. This ultimately significantly improves the stability of the converter blowing process. As a result, the final hot metal consumption per ton of steel produced is reduced to 960 kg / t to 980 kg / t, effectively reducing hot metal consumption by 85 kg / t compared to the traditional hot-pressed iron block addition method (Comparative Example 1).

[0102] In summary, the converter smelting method based on hot-pressed iron blocks provided in this application embodiment achieves a significant improvement in the stability of the converter blowing process through a full-process design that combines raw material substitution and adaptation, precise process control, process risk prevention and control, and equipment and cost coordination.

[0103] Furthermore, the present application provides a converter smelting method based on hot-pressed iron blocks. This converter smelting method, by clarifying the charging stage before converter blowing and specifying the specific proportions and timing of adding hot-pressed iron blocks, lightly calcined iron, and limestone slag in batches from the high-level silo, can significantly increase the amount of hot-pressed iron blocks used, forming a converter smelting method with high utilization of hot-pressed iron blocks. This supports a significant reduction in the consumption of molten iron in converter steel production, resulting in extremely low smelting cost advantages. At the same time, the blowing process of this converter smelting method has high stability and can avoid problems such as smoke and oxygen lance sticking together during the blowing process.

[0104] Furthermore, this application provides a converter smelting method based on hot-pressed iron blocks. This method dynamically adjusts the position of the oxygen lance in real time based on changes in the charging amount caused by the addition of hot-pressed iron blocks and real-time changes in the CO content in the flue gas. It is further supplemented by batch-addition control of slag to optimize the stability and efficiency of converter smelting. Simultaneously, based on the cost and compositional advantages of hot-pressed iron blocks, it is suitable for high-value-added steel grades and is of great significance in solving the technical bottleneck of the inability to properly add scrap steel to the scrap hopper due to overhead crane maintenance.

[0105] Furthermore, the converter smelting method based on hot-pressed iron blocks provided in this application embodiment has the following advantages: (1) The converter smelting method can use hot-pressed iron blocks as a substitute for scrap steel, which can solve the problem that the scrap steel bucket cannot be added normally due to the maintenance of the overhead crane, and ensure that the converter smelting process is not affected by equipment maintenance or failure, and can achieve continuous and stable production of molten steel. (2) The blowing process of this converter smelting method has high stability, which can effectively avoid the occurrence of splashing and smoke accidents and effectively reduce the pollution of the production environment caused by converter smelting.

[0106] (3) The slag material of this converter smelting method is added in batches and combined with stable blowing treatment, which can greatly reduce the probability of slag adhesion of the oxygen blowing lance, effectively extend the number of times the oxygen blowing lance is used by more than 125 times, improve the service life of the oxygen blowing lance, and reduce the maintenance and replacement time of the oxygen blowing lance by 40 minutes.

[0107] (4) Through precise process control and precise addition of hot-pressed iron blocks, this converter smelting method can more accurately control the consumption of molten iron in actual production and reduce the raw material cost of converter smelting.

[0108] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed in this application.

Claims

1. A hot briquetted iron based converter smelting method, characterized in that, The converter smelting method includes the following steps: The converter is desulfurized and then transferred to a separate container to obtain an iron tapping converter; The oxygen consumption is determined based on the loading capacity of the blast furnace. Based on the oxygen consumption and the smelting cycle of the tapping converter, the gradient preset oxygen blowing ratio and the smelting oxygen blowing ratio are determined. Limestone and the first hot-pressed iron block are added to the tapping converter for pre-feeding to adjust the slag system of the tapping converter and obtain pre-molten iron. Under the preset oxygen blowing ratio, batch materials are added to the pre-melted iron in batches for slag pressing to form slag in the pre-melting converter, thereby obtaining slag-containing molten iron; wherein, the batch materials include quicklime, lightly burned iron, and batch hot-pressed iron blocks; Under the specified blowing oxygen ratio conditions, the process material is added to the slag-containing molten iron for blowing treatment to obtain molten steel; wherein, the process material includes a second hot-pressed iron block; The molten steel is tapped to complete the converter smelting process.

2. The converter smelting method according to claim 1, characterized in that, Under the aforementioned gradient preset oxygen blowing ratio conditions, batches of material are added to the pre-melted iron in stages for slag pressing to form slag within the pre-melting converter, resulting in slag-containing molten iron. This process includes the following steps: Under the first oxygen blowing ratio condition, the first batch of material is added to the pre-melted iron for the first slag pressing operation to form a small amount of slag on the surface of the pre-melted iron, thereby obtaining process iron; wherein, the first batch of material includes the first quicklime, the first lightly calcined iron and the first batch of hot-pressed iron blocks; Under the second oxygen blowing ratio conditions, two batches of materials are added to the molten iron in the process for a second slag pressing operation to adjust the composition and properties of the slag and obtain slag-containing molten iron; wherein, the two batches of materials include a second batch of quicklime, a second batch of lightly burned iron, and a second batch of hot-pressed iron blocks.

3. The converter smelting method according to claim 2, characterized in that, The initial value of the first oxygen blowing ratio in the first slag pressing operation is ≥5%, and the final value of the first oxygen blowing ratio in the first slag pressing operation is <12%; and / or The initial value of the second oxygen blowing ratio in the second slag pressing operation is ≥12%, and the final value of the second oxygen blowing ratio in the second slag pressing operation is ≤16%.

4. The converter smelting method according to claim 2, characterized in that, The volume content of carbon monoxide in the second slag pressing operation is <40%.

5. The converter smelting method according to claim 2, characterized in that, The mass m1 of the first quicklime, the mass m2 of the first lightly burned lime, and the mass m3 of the first batch of hot-pressed iron blocks satisfy: m1:m2:m3 = (3.5 to 4.0):2:5; and / or The mass m4 of the second quicklime, the mass m5 of the second lightly burned iron, and the mass m6 of the second batch of hot-pressed iron blocks satisfy the following ratio: m4:m5:m6 = (3.0 to 4.0):1:

5.

6. The converter smelting method according to claim 1, characterized in that, The volume content of carbon monoxide in the blowing process is 40% to 60%.

7. The converter smelting method according to claim 1, characterized in that, When the blowing oxygen ratio is <25%, the actual liquid level h1 of the slag-containing molten iron and the normal liquid level h0 of the slag-containing molten iron satisfy: h0-h1=8cm to 10cm; When the blowing oxygen ratio is ≥25%, the actual liquid level h1 of the slag-containing molten iron and the normal liquid level h0 of the slag-containing molten iron satisfy: h0=h1.

8. The converter smelting method according to claim 1 or 6, characterized in that, When the actual time of the blowing process is less than or equal to 20% of the total time of the blowing process, the height of the blowing gun position in the blowing process is ≥200cm.

9. The converter smelting method according to claim 1, characterized in that, In the pre-feeding process, the first hot-pressed iron block is added in batches, and a shaking operation is performed before and after each batch addition, with the shaking angle ranging from -40° to 60°.

10. The converter smelting method according to claim 1, characterized in that, The mass m7 of the first hot-pressed iron block, the mass m8 of the batch hot-pressed iron block, and the mass m9 of the second hot-pressed iron block satisfy the following: m7:m8:m9=20:10:(0 to 10).

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