Method for adjusting alkalinity of blast furnace slag by using injection flux

Abstract

The invention relates to the technical field of blast furnace ironmaking, in particular to a method for adjusting the alkalinity of blast furnace slag by using a blowing flux. A furnace slag sample in a specific area in the furnace is obtained through a furnace inner radial sampling technology of the blast furnace; performing component analysis on the slag sample to obtain an actual alkalinity value of the slag sample; comparing the actual alkalinity value with a preset target alkalinity range; on the basis of the comparison result and the condition of raw fuel entering the furnace, dynamically determining the adding proportion of a flux needing to be injected through a calculation model; mixing the determined flux and pulverized coal through an injection system of the blast furnace, and injecting the mixture into the rotary area of the blast furnace so as to adjust the alkalinity of the slag to the target alkalinity range; and a closed-loop control loop is formed and is circularly executed in the blast furnace smelting process. Through combination of in-furnace radial sampling and an injection process, real-time and accurate closed-loop regulation and control on the alkalinity of the slag are realized, so that the smelting efficiency of the blast furnace is improved, and the fuel consumption is reduced.

Description

Technical Field

[0001] This invention relates to the field of blast furnace ironmaking technology, specifically a method for adjusting the basicity of blast furnace slag using injected flux. Background Technology

[0002] Blast furnace ironmaking is the mainstream method of producing molten iron in the modern steel industry, and its smelting process is essentially a complex slag-forming process. The basicity of the slag (usually referring to the mass ratio of CaO / SiO2) is a key indicator affecting the smooth operation of the blast furnace, desulfurization efficiency, fuel consumption, and the quality of molten iron.

[0003] Currently, blast furnaces in my country generally adopt a burden structure consisting of high-basicity sintered ore combined with acidic pellets or lump ore. While this structure is beneficial for improving the permeability of the upper and middle burden column, it can also easily lead to excessive slag and liquid phase concentration in the lower belly area, worsening permeability and negatively impacting the desulfurization and desiliconization reaction balance within the furnace, ultimately resulting in an increase in the fuel ratio.

[0004] To optimize slag performance, various technical solutions have been proposed by those skilled in the art. Among them, adjusting slag composition through flux injection is a recognized effective approach. However, existing technologies mostly focus on improving flux type, injection system, or process parameters, neglecting a fundamental problem: the blast furnace is a "black box" reactor, and existing technologies cannot accurately and in real time grasp the composition and physical property data of the actual slag-forming process inside the furnace. This leads to flux injection regulation relying heavily on experience or laboratory simulations, lacking a precise data foundation, resulting in unstable control effects and difficulty in achieving dynamic optimization.

[0005] Existing technologies disclose various related jetting methods, such as: Chinese patent document CN85107133A, entitled "Blast Furnace Injection Flux," proposes injecting a portion of the flux through the tuyeres to reduce the sulfur content of pig iron. However, its focus is on sulfur distribution and does not address how to precisely control the flux based on the state of the slag within the furnace. Chinese patent document CN115216569B, entitled "A Method for Controlling Blast Furnace Injection Flux Process Parameters Based on Theoretical Combustion Temperature," uses theoretical combustion temperature to reversely adjust process parameters. While this method considers heat balance, it does not directly detect or provide feedback on the slag composition itself, representing an indirect control method. Chinese patent document CN118460801A, entitled "A Method for Selecting Tuyere Injection Flux Based on the Flowability of Coal, Coke, and Ash Slag in the Tuyere Area," while beginning to focus on the slag sample performance in the tuyeres area, is based on coal, coke, and ash slag, rather than the slag-forming products of the main blast furnace burden, thus failing to comprehensively reflect the overall alkalinity state within the furnace. Furthermore, the Chinese patent document CN115386667B, entitled "A Method for Adjusting the Basicity of Blast Furnace Slag," adjusts the basicity by adding quartz blocks to the top of the furnace. This method alters the structure of the upper furnace charge and may cause new problems such as the upward movement of the softening zone.

[0006] In summary, existing technologies for adjusting slag basicity by injecting flux generally suffer from insufficient perception of the actual reaction state within the furnace, inadequate control basis, and lagging dynamic response. Therefore, developing an injection method that can directly acquire slag information within the furnace and perform real-time, precise, and closed-loop control based on this information is of great significance for improving blast furnace smelting efficiency and reducing fuel consumption, which constitutes the starting point for this invention. Summary of the Invention

[0007] To overcome the shortcomings of existing technologies, this invention provides a method for adjusting the basicity of blast furnace slag using injected flux. By combining radial sampling inside the furnace with the injection process, real-time and precise closed-loop control of slag basicity is achieved, thereby improving blast furnace smelting efficiency and reducing fuel consumption.

[0008] To achieve the above objectives, the present invention employs the following technical solution: A method for adjusting the basicity of blast furnace slag using injected flux, wherein the method is performed without altering the structure of the upper burden in the blast furnace, includes the following steps: S1 uses radial sampling technology inside the blast furnace to obtain slag samples from specific areas inside the furnace; S2 performs component analysis on the slag sample to obtain its actual alkalinity value; S3 compares the actual alkalinity value with the preset target alkalinity range; Based on the comparison results and the conditions of the raw materials entering the furnace, S4 dynamically determines the proportion of flux to be injected through a calculation model. S5 uses the blast furnace injection system to mix the determined flux with pulverized coal and inject it into the blast furnace swirl zone to adjust the slag basicity to the target basicity range. S1 to S5 form a closed-loop control circuit, which is executed cyclically during the blast furnace smelting process.

[0009] Furthermore, in S1, the specific area is the drip zone and / or the furnace belly area.

[0010] Furthermore, in step S4, the flux is an alkaline flux used to increase the alkalinity of the slag; the alkaline flux includes one or more of limestone powder, quicklime powder, and dolomite powder.

[0011] Furthermore, in S4, the flux is an acidic flux used to reduce the basicity of the slag; the acidic flux is quartz powder.

[0012] Furthermore, in step S4, the flux mixing ratio is determined by the following formula: In the formula: flux mr The flux content in the mixed pulverized coal is %; ore cq The amount of ore consumed in the production of tonnes of iron, expressed in kg / t; CaO ore The calcium oxide content in the ore fed into the furnace, % coke ef The coke ratio for iron production per ton of furnace, in kg / t; ASH coke The ash content of the coke entering the furnace is % CaO coke The calcium oxide content in the ash of the coke entering the furnace, % PCI stands for pulverized coal injection per ton of iron production, in kg / t. ASH coal The ash content of pulverized coal is %; CaO coal The calcium oxide content in the ash of pulverized coal is % (%). SiO 2ore The silica content in the ore fed into the furnace, % SiO 2coke The silica content in the ash of the coke entering the furnace is % (%). SiO 2coal The silica content in the ash of pulverized coal is % (%). m1, m2, and m3 are constants.

[0013] Furthermore, m1 is 0.96, m2 is 1.03, and m3 is 4.57.

[0014] Furthermore, ore cq The concentration of CaO is 1500~1750 kg / t. ore It ranges from 5% to 12%, according to Coke. ef 280~520kg / t, ASH coke The content is 10.5%~14.5%, CaO coke The percentage is 1.0%~7.0%, PCI is 80~220 kg / t, and ASH is... coal The content of CaO ranges from 6.0% to 13.5%. coal The content is 1.5%~12.5%, SiO 2ore The content is 3.5%~8.0%, SiO 2coke It is 20%~60%, SiO 2coal It ranges from 25% to 65%.

[0015] Furthermore, in S5, the injection system is a pulverized coal injection system for a blast furnace, where flux and pulverized coal are mixed and injected into the blast furnace vortex zone through tuyeres.

[0016] Furthermore, in S5, the pulverized coal is one or more of anthracite, bituminous coal, lean coal, semi-lean coal, and lignite.

[0017] Furthermore, it also includes alternative coal types, which consist of one or more of the following: semi-coke, upgraded coal, CDQ powder (dry quenching coke dust), water-quenched coke powder, blast furnace dust, and biomass fuel.

[0018] Blast furnace dust consists of one or more of the following: ore and coke bin dust, furnace top dust, and furnace front dust produced during the blast furnace smelting process. Biomass fuel consists of one or more of the following: charcoal, straw, fruitwood husks, and carbonized rice husks.

[0019] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention achieves precise and real-time control of slag alkalinity, fundamentally solving the problem of "black box operation." It introduces "radial sampling technology within the furnace," enabling direct acquisition of real slag samples from key areas such as the drip zone and furnace belly. This allows control decisions to be based on first-hand real-time data, rather than experience or outdated manual test results. By constructing a closed-loop control circuit encompassing sampling, analysis, comparison, calculation, and injection, the system can dynamically respond to changes in furnace conditions, achieving a qualitative leap from "experience-based, extensive" adjustment to "data-driven, refined" control, significantly improving the accuracy and stability of alkalinity control.

[0020] 2. Significantly optimizes blast furnace operation and effectively reduces fuel consumption. Because it can precisely control slag basicity within the optimal target range, this invention directly improves the physicochemical properties of the slag: Improved slag fluidity: The appropriate alkalinity ensures that the slag has good fluidity, which greatly improves the permeability and liquid permeability of the lower part of the blast furnace, making the gas distribution more uniform and the carburization and dripping process of molten iron smoother.

[0021] Improved thermodynamic conditions: The optimized slag composition creates better thermodynamic conditions for in-furnace desulfurization and desiliconization reactions, thereby improving reaction efficiency.

[0022] Overall effect: The above two points work together to effectively reduce the blast furnace pressure difference and promote smooth furnace operation. Thus, without changing the upper furnace charge structure or increasing the cost of expensive raw materials, the fuel ratio (coke ratio) is reduced, achieving the goal of low-consumption and high-efficiency smelting.

[0023] 3. The control methods are flexible and economical, and do not affect the existing production system. This invention makes full use of the existing pulverized coal injection system of the blast furnace, mixing and injecting flux with pulverized coal. This invention offers great convenience and economy in implementation: no major equipment modifications are required, and investment costs are low. Based on analysis results, alkaline fluxes (such as limestone powder) or acidic fluxes (such as quartz powder) can be flexibly selected to achieve "two-way" adjustment of slag alkalinity, addressing different production needs. The invention allows the use of substitutes such as semi-coke and dry quenching coke dust, which not only reduces production costs but also achieves resource utilization of solid waste, resulting in environmental benefits.

[0024] 4. It provides a scientifically quantifiable basis for decision-making, enhancing the level of intelligent operation. The core calculation formula of this invention is not a simple empirical formula, but rather a comprehensive mass balance model that takes into account the chemical composition and consumption of various raw materials and fuels fed into the furnace, such as ore, coke, and pulverized coal. The introduction of constants is a scientific fit to the complex reaction environment of the actual blast furnace. This calculation model elevates the operator's decision-making process from "qualitative judgment" to "quantitative calculation," reducing human uncertainty. It provides the core algorithmic foundation for realizing "intelligent" and "automated" control of blast furnace smelting, making continuous optimization possible.

[0025] In summary, this invention effectively solves the long-standing problem of precise slag control in blast furnace ironmaking by leveraging the synergistic effect of "data acquisition, intelligent decision-making, and precise execution," resulting in significant benefits in improving product quality, reducing energy consumption, and enhancing operational stability. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0027] A method for adjusting the basicity of furnace slag by injecting flux includes the following steps: 1. Obtaining real data inside the furnace through radial sampling Under normal blast furnace smelting conditions, slag samples were successfully extracted from the drip zone and belly area using a radial sampling device inside the blast furnace. The obtained samples were sent to the laboratory for rapid component analysis to obtain their actual alkalinity values.

[0028] 2. Compare the actual alkalinity value with the preset target alkalinity range. Upon comparison, the actual basicity value was found to be lower than the lower limit of the target basicity range. Therefore, the system determined that an alkaline flux needed to be injected to increase the basicity of the slag. In this example, one or more of limestone, converter slag, and quicklime were selected as the injection flux.

[0029] 3. Determine the precise flux mixing ratio through a calculation model. In the formula: flux mr The flux content in the mixed pulverized coal is %; ore cq The amount of ore consumed in the production of tonnes of iron, expressed in kg / t; CaO ore The calcium oxide content in the ore fed into the furnace, % coke ef The coke ratio for iron production per ton of furnace, in kg / t; ASH coke The ash content of the coke entering the furnace is % CaO coke The calcium oxide content in the ash of the coke entering the furnace, % PCI stands for pulverized coal injection per ton of iron production, in kg / t. ASH coal The ash content of pulverized coal is %; CaO coal The calcium oxide content in the ash of pulverized coal is % (%). SiO 2ore The silica content in the ore fed into the furnace, % SiO 2coke The silica content in the ash of the coke entering the furnace is % (%). SiO 2coal The silica content in the ash of pulverized coal is % (%). m1 is 0.96, m2 is 1.03, and m3 is 4.57.

[0030] Furthermore, controlling ore cq The concentration of CaO is 1500~1750 kg / t. ore It ranges from 5% to 12%, according to Coke.ef 280~520kg / t, ASH coke The content is 10.5%~14.5%, CaO coke The percentage is 1.0%~7.0%, PCI is 80~220 kg / t, and ASH is... coal The content is 6.0%~3.5%, CaO coal The content is 1.5%~12.5%, SiO 2ore The content is 3.5%~8.0%, SiO 2coke It is 20%~60%, SiO 2coal The content ranges from 25% to 65%. All the above contents are percentages by mass.

[0031] 4. Through calculation, it was determined that under the current raw material conditions, the amount of flux to be added to the mixed coal powder is required to increase the alkalinity from the actual alkalinity value to the target alkalinity value.

[0032] 5. The flux is mixed with pulverized coal for blast furnace injection and then injected into the blast furnace vortex zone. The main technical measures adopted are to place the flux in a special silo and mix it with different types of pulverized coal for blast furnace injection according to a certain proportion through a feeding device. The mixed pulverized coal is then injected into the blast furnace vortex zone after multiple processes such as grinding in a mill, coal powder collection, fluidization in an injection tank, pipeline transportation, and injection by a pulverized coal lance.

[0033] 6. After approximately one smelting cycle of the injection operation, the system restarts the radial sampling and analysis process from step 1 to measure the alkalinity of the new slag sample. If the value has successfully entered the target range, the system records the success of this adjustment and, based on the new production data, enters the next round of monitoring and fine-tuning cycle, thereby achieving continuous optimization and stable control of the entire blast furnace smelting process.

[0034] Example 1 (at 300m) 3 Implementation case of adjusting slag basicity by injecting flux in a blast furnace (all contents in the examples are mass percentages). 1. Flux spraying situation A steel plant has an effective furnace volume of 300m³. 3 For details on the flux injection in the blast furnace, please refer to Table 1-1.

[0035] Table 1-1 Blast Furnace Flux Injection Status 2. Raw materials and fuel entering the furnace For details on the raw materials and fuels used in the blast furnace, please refer to Table 1-2.

[0036] Table 1-2 Raw material and fuel conditions for blast furnace charging 3. Flux ratio in mixed pulverized coal The analysis results of the flux proportion in the mixed pulverized coal under the above-mentioned raw material and fuel operating conditions are detailed in Table 1-3.

[0037] Table 1-3 Flux Proportion in Mixed Pulverized Coal 4. Results achieved by the blast furnace The effects achieved by the blast furnace after injecting flux using the above scheme are detailed in Table 1-4.

[0038] Table 1-4 Results of Blast Furnace Smelting By applying the above technical solution to a blast furnace with an effective furnace volume of 300m³ in a steel plant, adding 3.20% converter slag to the mixed pulverized coal, and using the existing pulverized coal injection process for injection, the blast furnace operation was significantly improved, with the following specific results: daily blast furnace output increased by 24t; fuel consumption decreased by 2.0kg / t.

[0039] This embodiment demonstrates that by using the present invention to improve the slag basicity of an operating blast furnace, it is possible to effectively: enhance the blast furnace's permeability and liquid permeability; and optimize the in-furnace desulfurization and desiliconization reaction processes. This, in turn, achieves the goals of improving blast furnace smelting efficiency and reducing fuel consumption, ultimately resulting in low-consumption, high-efficiency, and low-cost ironmaking production.

[0040] Example 2 (at 1800m) 3 (Case study on adjusting slag basicity by injecting flux in a blast furnace) 1. Flux spraying situation A steel plant has an effective furnace volume of 1800m³. 3 For details on the flux injection in the blast furnace, please refer to Table 2-1.

[0041] Table 2-1 Blast Furnace Flux Injection Status 2. Raw materials and fuel entering the furnace For details on the raw materials and fuels used in the blast furnace, please refer to Table 2-2.

[0042] Table 2-2 Raw Material Conditions for Blast Furnace Charging 3. Flux ratio in mixed pulverized coal The analysis results of the flux proportion in the mixed pulverized coal under the above-mentioned raw material and fuel operating conditions are detailed in Table 2-3.

[0043] Table 2-3 Flux Proportion in Mixed Pulverized Coal 4. Results achieved by the blast furnace The effects achieved by the blast furnace after injecting flux using the above scheme are detailed in Table 2-4.

[0044] Table 2-4 Results of Blast Furnace Smelting By applying the above technical solution to a blast furnace with an effective furnace volume of 1800m³ in a steel plant, after adding 3.46% converter slag to the mixed pulverized coal and using the existing pulverized coal injection process for injection, the blast furnace operation was significantly improved, with the following results: daily blast furnace output increased by 35t; fuel consumption decreased by 1.0kg / t.

[0045] This embodiment demonstrates that by using the present invention to improve the slag basicity of an operating blast furnace, it is possible to effectively: enhance the blast furnace's permeability and liquid permeability; and optimize the in-furnace desulfurization and desiliconization reaction processes. This, in turn, achieves the goals of improving blast furnace smelting efficiency and reducing fuel consumption, ultimately resulting in low-consumption, high-efficiency, and low-cost ironmaking production.

[0046] Example 3 (at 2580m) 3 (Case study on adjusting slag basicity by injecting flux in a blast furnace) 1. Flux spraying situation A steel plant has an effective furnace volume of 2580m³. 3 For details on the flux injection in the blast furnace, please refer to Table 3-1.

[0047] Table 3-1 Blast Furnace Flux Injection Status 2. Raw materials and fuel entering the furnace For details on the raw materials and fuels used in the blast furnace, please refer to Table 3-2.

[0048] Table 3-2 Raw material and fuel conditions for blast furnace charging 3. Flux ratio in mixed pulverized coal The analysis results of the flux proportion in the mixed pulverized coal under the above-mentioned raw material and fuel operating conditions are detailed in Table 3-3.

[0049] Table 3-3 Flux Proportion in Mixed Pulverized Coal 4. Results achieved by the blast furnace The effects achieved by the blast furnace after injecting flux using the above scheme are detailed in Table 3-4.

[0050] Table 3-4 Results of Blast Furnace Smelting By applying the above technical solution to a blast furnace with an effective furnace volume of 2580m³ in a steel plant, after adding 3.16% converter slag to the mixed pulverized coal and using the existing pulverized coal injection process for injection, the blast furnace operation was significantly improved, with the following results: daily blast furnace output increased by 16t, and fuel consumption decreased by 2.2kg / t.

[0051] This embodiment demonstrates that by using the present invention to improve the slag basicity of an operating blast furnace, it is possible to effectively: enhance the blast furnace's permeability and liquid permeability; and optimize the in-furnace desulfurization and desiliconization reaction processes. This, in turn, achieves the goals of improving blast furnace smelting efficiency and reducing fuel consumption, ultimately resulting in low-consumption, high-efficiency, and low-cost ironmaking production.

[0052] Example 4 (at 3200m) 3 (Case study on adjusting slag basicity by injecting flux in a blast furnace) 1. Flux spraying situation A steel plant has an effective furnace volume of 3200 m³. 3 For details on the flux injection in the blast furnace, please refer to Table 4-1.

[0053] Table 4-1 Blast Furnace Flux Injection Status 2. Raw materials and fuel entering the furnace For details on the raw materials and fuels used in the blast furnace, please refer to Table 4-2.

[0054] Table 4-2 Raw material and fuel conditions for blast furnace charging 3. Flux ratio in mixed pulverized coal The analysis results of the flux proportion in the mixed pulverized coal under the above-mentioned raw material and fuel operating conditions are detailed in Table 4-3.

[0055] Table 4-3 Flux Proportion in Mixed Pulverized Coal 4. Results achieved by the blast furnace The effects achieved by the blast furnace after injecting flux using the above scheme are detailed in Table 4-4.

[0056] Table 4-4 Results of Blast Furnace Smelting Through analysis of the effective furnace volume of a steel plant of 3200m³ 3 By applying the above technical solution to the blast furnace, adding 4.35% converter slag to the mixed pulverized coal, and using the existing pulverized coal injection process for injection, the blast furnace operation has been significantly improved, with the following specific results: daily blast furnace output increased by 47t; fuel consumption decreased by 1.5kg / t.

[0057] This embodiment demonstrates that by using the present invention to improve the slag basicity of an operating blast furnace, it is possible to effectively: enhance the blast furnace's permeability and liquid permeability; and optimize the in-furnace desulfurization and desiliconization reaction processes. This, in turn, achieves the goals of improving blast furnace smelting efficiency and reducing fuel consumption, ultimately resulting in low-consumption, high-efficiency, and low-cost ironmaking production.

[0058] Example 5 (at 4038m) 3 (Case study on adjusting slag basicity by injecting flux in a blast furnace) 1. Flux spraying situation A steel plant has an effective furnace volume of 4038 m³. 3 For details on the flux injection in the blast furnace, please refer to Table 5-1.

[0059] Table 5-1 Blast Furnace Flux Injection Status 2. Raw materials and fuel entering the furnace For details on the raw materials and fuels used in the blast furnace, please refer to Table 5-2.

[0060] Table 5-2 Raw Material and Fuel Conditions for Blast Furnace Charging 3. Flux ratio in mixed pulverized coal The analysis results of the flux proportion in the mixed pulverized coal under the above-mentioned raw material and fuel operating conditions are detailed in Table 5-3.

[0061] Table 5-3 Flux Proportion in Mixed Pulverized Coal 4. Results achieved by the blast furnace The effects achieved by the blast furnace after injecting flux using the above scheme are detailed in Table 5-4.

[0062] Table 5-4 Results of Blast Furnace Smelting The effective furnace volume of a certain steel plant is 4038m³. 3 By applying the above technical solution to the blast furnace, adding 3.12% converter slag to the mixed pulverized coal, and using the existing pulverized coal injection process for injection, the blast furnace operation has been significantly improved, with the following specific results: daily blast furnace output increased by 35t; fuel consumption decreased by 2.5kg / t.

[0063] This embodiment demonstrates that by using the present invention to improve the slag basicity of an operating blast furnace, it is possible to effectively: enhance the blast furnace's permeability and liquid permeability; and optimize the in-furnace desulfurization and desiliconization reaction processes. This, in turn, achieves the goals of improving blast furnace smelting efficiency and reducing fuel consumption, ultimately resulting in low-consumption, high-efficiency, and low-cost ironmaking production.

[0064] Example 6 (at 5500m) 3 (Case study on adjusting slag basicity by injecting flux in a blast furnace) 1. Flux spraying situation A steel plant has an effective furnace volume of 5500 m³. 3 For details on the flux injection in the blast furnace, please refer to Table 6-1.

[0065] Table 6-1 Blast Furnace Flux Injection Status 2. Raw materials and fuel entering the furnace For details on the raw materials and fuels used in the blast furnace, please refer to Table 6-2.

[0066] Table 6-2 Blast Furnace Raw Material Conditions 3. Flux ratio in mixed pulverized coal The analysis results of the flux proportion in the mixed pulverized coal under the above-mentioned raw material and fuel operating conditions are detailed in Table 6-3.

[0067] Table 6-3 Flux Proportion in Mixed Pulverized Coal 4. Results achieved by the blast furnace The effects achieved by the blast furnace after injecting flux using the above scheme are detailed in Table 6-4.

[0068] Table 6-4 Results of Blast Furnace Smelting Through analysis of a steel plant with an effective furnace volume of 5500m³ 3 By applying the above technical solution to the blast furnace, adding 3.29% converter slag to the mixed pulverized coal, and using the existing pulverized coal injection process for injection, the blast furnace operation has been significantly improved, with the following specific results: daily blast furnace output increased by 52t; fuel consumption decreased by 2.2kg / t.

[0069] This embodiment demonstrates that by using the present invention to improve the slag basicity of an operating blast furnace, it is possible to effectively: enhance the blast furnace's permeability and liquid permeability; and optimize the in-furnace desulfurization and desiliconization reaction processes. This, in turn, achieves the goals of improving blast furnace smelting efficiency and reducing fuel consumption, ultimately resulting in low-consumption, high-efficiency, and low-cost ironmaking production.

[0070] The above embodiments implemented the present invention under different effective furnace volumes (from 300m³ to 5500m³), different flux types (converter slag, quicklime powder, quartz powder, etc.), and different raw material conditions. Based on the combined effects of all implementations, the following clear conclusions can be drawn: the injection control method based on in-furnace radial sampling and calculation models provided by the present invention can be successfully applied to blast furnaces with different furnace volumes and different charge structures, without being limited by the scale of the blast furnace, proving its wide applicability in production. All cases successfully adjusted the slag basicity using the described method, stabilizing it within the preset target range. This confirms that the present invention can fundamentally overcome the drawbacks of "black box operation," achieving a shift from experience-based control to data-driven, precise, closed-loop control. After implementing the present invention, all blast furnaces exhibited the common characteristics of improved permeability and liquid permeability, and enhanced furnace stability. This indicates that optimizing slag basicity directly and effectively improves the operating state of the lower part of the blast furnace. All cases achieved the practical effect of reducing fuel consumption (fuel ratio). This consistently proves that the present invention is an effective way to achieve low-consumption and high-efficiency smelting in blast furnaces. While achieving energy conservation, some cases have also brought the additional benefit of increased blast furnace output. This indicates that the present invention can not only reduce unit production costs, but also tap production potential by improving smelting intensity, resulting in significant comprehensive economic benefits.

[0071] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for adjusting the basicity of blast furnace slag using injected flux, characterized in that, Includes the following steps: S1 uses radial sampling technology inside the blast furnace to obtain slag samples from specific areas inside the furnace; S2 performs component analysis on the slag sample to obtain its actual alkalinity value; S3 compares the actual alkalinity value with the preset target alkalinity range; Based on the comparison results and the conditions of the raw materials entering the furnace, S4 dynamically determines the proportion of flux to be injected through a calculation model. S5 uses the blast furnace injection system to mix the determined flux with pulverized coal and inject it into the blast furnace swirl zone to adjust the slag basicity to the target basicity range.

2. The method for adjusting the basicity of blast furnace slag using injected flux according to claim 1, characterized in that, In S1, the specific area is the drip zone and / or the furnace belly area.

3. The method for adjusting the basicity of blast furnace slag using injected flux according to claim 1, characterized in that, In step S4, the flux is an alkaline flux used to increase the alkalinity of the slag; the alkaline flux includes one or more of limestone powder, quicklime powder, and dolomite powder.

4. The method for adjusting the basicity of blast furnace slag using injected flux according to claim 1, characterized in that, In S4, the flux is an acidic flux used to reduce the alkalinity of the slag; the acidic flux is quartz powder.

5. The method for adjusting the basicity of blast furnace slag using injected flux according to claim 1, characterized in that, In step S4, the flux mixing ratio is determined by the following formula: In the formula: flux mr The flux content in the mixed pulverized coal is %; ore cq The amount of ore consumed in the production of tonnes of iron, expressed in kg / t; CaO ore The calcium oxide content in the ore fed into the furnace, % coke ef The coke ratio for iron production per ton of furnace, in kg / t; ASH coke The ash content of the coke entering the furnace is % CaO coke The calcium oxide content in the ash of the coke entering the furnace, % PCI stands for pulverized coal injection per ton of iron production, in kg / t. ASH coal The ash content of pulverized coal is %; CaO coal The calcium oxide content in the ash of pulverized coal is % (%). SiO 2ore The silica content in the ore fed into the furnace, % SiO 2coke The silica content in the ash of the coke entering the furnace is % (%). SiO 2coal The silica content in the ash of pulverized coal is % (%). m1, m2, and m3 are constants.

6. The method for adjusting the basicity of blast furnace slag using injected flux according to claim 5, characterized in that, ore cq The concentration of CaO is 1500~1750 kg / t. ore It ranges from 5% to 12%, according to Coke. ef 280~520kg / t, ASH coke The content is 10.5%~14.5%, CaO coke The percentage is 1.0%~7.0%, PCI is 80~220 kg / t, and ASH is... coal The content of CaO ranges from 6.0% to 13.5%. coal The content is 1.5%~12.5%, SiO 2ore The content is 3.5%~8.0%, SiO 2coke It is 20%~60%, SiO 2coal It ranges from 25% to 65%.

7. The method for adjusting the basicity of blast furnace slag using injected flux according to claim 1, characterized in that, In S5, the injection system is the pulverized coal injection system of the blast furnace. The flux and pulverized coal are mixed and injected into the blast furnace vortex zone through the tuyeres.

8. The method for adjusting the basicity of blast furnace slag using injected flux according to claim 1, characterized in that, In step S5, the pulverized coal is one or more of anthracite, bituminous coal, lean coal, semi-lean coal, and lignite.

9. The method for adjusting the basicity of blast furnace slag using injected flux according to claim 1, characterized in that, It also includes alternative coal types, which consist of one or more of the following: semi-coke, upgraded coal, CDQ powder (dry quenching coke dust), water-quenched coke powder, blast furnace dust, and biomass fuel.

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