Charge structure

Abstract

The application relates to a burden structure, which comprises: 3.94-37.07% of full-secret fine powder sinter, 2.63-55.89% of common sinter, and 40-60% of acid pellet; the full-secret fine powder sinter comprises: 54-55% of TFe, 16.11-17.11% of CaO, 2.95-3.35% of SiO2, 1.0-1.5% of Al2O3, and 1.07-2.07% of MgO; the full-secret fine powder sinter has a reduction disintegration index, and the proportion of the particle size greater than 6.3 mm is 94-95%; when the burden structure is used for smelting, the proportion of the acid pellet can be greater than 40%, and the furnace-in grade can be greater than 60%; the burden structure has good low-temperature disintegration, reduction degree and molten drop performance when smelting; and the burden structure breaks the limitation that alkali pellet must be used for developing high-proportion pellet blast furnace smelting technology.

Description

Technical Field

[0001] This application relates to the field of blast furnace ironmaking technology, and in particular to a furnace charge structure. Background Technology

[0002] In the iron and steel metallurgy industry, blast furnace smelting is the mainstream ironmaking process, and the rationality of its furnace charge structure directly affects smelting efficiency, energy consumption, and environmental performance. Currently, the blast furnace charge structure of most steel companies in the industry is mainly composed of sintered ore, usually mixed with a small proportion of lump ore and acidic pellets; some companies use alkaline pellets to replace acidic pellets.

[0003] However, existing blast furnace charge structures still have many technical shortcomings in practical applications, including: (1) The proportion of acidic pellets added is limited. The use of acidic pellets requires blending with sinter to balance the basicity of blast furnace slag. In existing processes, the reasonable basicity range of sinter is usually controlled between 1.9 and 2.3. This upper limit of basicity imposes a strict constraint on the proportion of acidic pellets added, making it difficult to increase their proportion in the furnace charge and thus failing to fully leverage the advantages of high-grade pellets.

[0004] (2) The overall grade of the feed material is low and the amount of slag generated is large. The iron grade of sintered ore is generally lower than that of pellets, and the limitation on the proportion of acidic pellets directly leads to a decrease in the overall grade of blast furnace feed. Low-grade feed will generate a large amount of slag during the smelting process, which will not only increase the blast furnace slag discharge load, but also reduce smelting efficiency and increase energy consumption.

[0005] (3) Total carbon emissions are too high The low proportion of pellets in the furnace charge structure is an important reason for the increase in carbon emissions: on the one hand, the unit carbon emissions of the sintering process are significantly higher than those of the pelletizing process, and the insufficient proportion of pellets will increase the proportion of high-carbon sinter; on the other hand, the lower grade of the charge will lead to an increase in coke consumption during the blast furnace smelting process, further pushing up the total carbon emissions, which is contrary to the promotion of the "dual carbon" target of the steel industry.

[0006] (4) The application of alkaline pellets has limitations. Although alkaline pellets can alleviate the constraints of acidic pellets on slag alkalinity to some extent, firstly, their production process and equipment require a large investment scale, demanding high financial strength from enterprises; secondly, the production of alkaline pellets has strict requirements on indicators such as SiO2 content of raw material powder, and most steel enterprises are unable to meet the conditions for large-scale production of alkaline pellets due to raw material conditions or cost limitations, thus limiting its application scope.

[0007] In view of this, it is necessary to design a furnace charge structure to solve the above problems. Summary of the Invention

[0008] This application provides a furnace charge structure to solve the problems of limited pellet proportion in current furnace charges, low grade of feed, and high carbon emissions. In a first aspect, this application provides a furnace charge structure, wherein the chemical composition of the furnace charge structure, by mass percentage, comprises: whole fine sintered ore: 3.94%~37.07%, ordinary sintered ore: 2.63%~55.89%, and acidic pellets: 40%~60%; The chemical composition of the whole fine powder sintered ore, by mass percentage, includes: TFe: 54%~55%, CaO: 16.11%~17.11%, SiO2: 2.95%~3.35%, Al2O3: 1.0%~1.5%, MgO: 1.07%~2.07%.

[0009] In some embodiments, the drum strength of the whole-grain fine powder sinter is 80%~90%; and / or, In the reduction pulverization index of the whole-mil fine sinter, the whole-mil fine sinter with a particle size greater than 3.15 mm accounts for 95%~98%; in the reduction pulverization index of the whole-mil fine sinter, the whole-mil fine sinter with a particle size greater than 6.3 mm accounts for 94%~95%; and / or, The reducibility of the whole fine powder sintered ore is 78%~80%.

[0010] In some embodiments, the mass percentage of particles with a diameter of 0.074 mm in the whole fine powder sinter is 85% to 90%.

[0011] In some embodiments, the basicity of the whole-fine sintered ore is 5 to 5.5.

[0012] In some embodiments, the chemical composition of the ordinary sinter, by mass percentage, includes: TFe: 56.12%~56.51%, CaO: 10.17%~10.67%, SiO2: 5.33%~5.35%, Al2O3: 2%~2.21%, MgO: 1.39%~1.44%.

[0013] In some embodiments, the basicity of the ordinary sinter is 1.9 to 2.0.

[0014] In some embodiments, the particle size of the ordinary sintered ore is 19mm~23mm.

[0015] In some embodiments, the chemical composition of the acidic pellets, by mass percentage, includes: TFe: 65.12%~65.52%, CaO: 0.29%~0.49%, SiO2: 4.35%~4.95%, Al2O3: 0.34%~0.54%, MgO: 0.8%~1.0%.

[0016] In some embodiments, the basicity of the acidic pellets is 0.03 to 0.09.

[0017] In some embodiments, the compressive strength of the acidic pellets is 2800N~3700N; the reduction expansion rate is 10%~15%.

[0018] The technical solutions provided in this application have the following advantages compared with the prior art: The furnace charge structure provided in this application embodiment has the following chemical composition: 3.94%~37.07% pure sinter, 2.63%~55.89% ordinary sinter, and 40%~60% acidic pellets. By mass percentage, the pure sinter composition includes: TFe: 54%~55%, CaO: 16.11%~17.11%, SiO2: 2.95%~3.35%, Al2O3: 1.0%~1.5%, and MgO: 1.07%~2.07%. Using this furnace charge structure allows for a higher grade of acidic pellets than 40% while maintaining a higher grade than 60%, effectively reducing the blast furnace coke ratio. Furthermore, this furnace charge structure exhibits excellent low-temperature pulverization, reduction, and dripping properties during smelting. This undoubtedly overcomes the limitation that developing high-proportion pellet blast furnace smelting technology requires the use of alkaline pellets. In addition, by adopting the furnace charge structure provided in this application, the proportion of acidic pellets fed into the furnace can be increased, thereby reducing the impact of SiO2 content in mineral powder on pellet production and alleviating the problem of insufficient low-SiO2 mineral powder reserves. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be described clearly and completely below. 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] Various embodiments of this application may exist in the form of a range. It should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of this application. Therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. In addition, whenever a numerical range is indicated in this application, it means including any referenced number (fraction or integer) within the indicated range. Unless otherwise specified, all raw materials, reagents, instruments, and equipment used in this application can be purchased commercially or prepared by existing methods. In this application, the terms "comprising," "including," etc., mean "including but not limited to." In this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, without necessarily requiring or implying any actual relationship or order between these entities or operations. In this application, "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this application, "at least one" means one or more, and "more than one" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c," or "at least one of a, b, and c," can both represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can each be single or multiple.

[0021] This application provides a furnace charge structure, the chemical composition of which, by mass percentage, includes: whole fine sintered ore: 3.94%~37.07%, ordinary sintered ore: 2.63%~55.89%, and acidic pellets: 40%~60%. The chemical composition of the whole fine powder sintered ore, by mass percentage, includes: TFe: 54%~55%, CaO: 16.11%~17.11%, SiO2: 2.95%~3.35%, Al2O3: 1.0%~1.5%, MgO: 1.07%~2.07%.

[0022] Thus, by using a fully alkaline fine sintered ore with an alkalinity of 5.0 to 5.5, the proportion of acidic pellets in the blast furnace can exceed 40%, while maintaining the grade of the blast furnace feed at over 60%, which can effectively reduce the coke ratio in the blast furnace. Furthermore, this type of charge structure exhibits good low-temperature pulverization, reduction, and dripping properties during smelting. This breaks through the limitation that the development of high-proportion pellet blast furnace smelting technology must use alkaline pellets.

[0023] Furthermore, in the embodiments of this application, the drum strength of the whole fine powder sinter is 80%~90%.

[0024] This helps to increase the strength of the ore fed into the furnace, reduce the amount of powder produced, and thus improve the permeability of the blast furnace.

[0025] Furthermore, in the embodiments of this application, the particle size of the fine sintered ore with a reduction pulverization index greater than 3.15 mm accounts for 95% to 98%; the particle size of the fine sintered ore with a reduction pulverization index greater than 6.3 mm accounts for 94% to 95%.

[0026] Preferably, in the reduction pulverization index of the whole-mil fine sinter, the whole-mil fine sinter with a particle size greater than 3.15 mm accounts for 97.7%; and in the reduction pulverization index of the whole-mil fine sinter, the whole-mil fine sinter with a particle size greater than 6.3 mm accounts for 94.94%.

[0027] This helps improve the permeability of the upper part of the blast furnace.

[0028] The reducibility of the whole fine powder sintered ore is 78%~80%.

[0029] This helps to reduce the coke ratio and fuel ratio in the blast furnace.

[0030] Furthermore, in the embodiments of this application, the mass percentage of particles with a particle size of 0.074 mm in the whole fine powder sinter is 85%~90%.

[0031] Furthermore, in the embodiments of this application, the basicity of the whole fine powder sintered ore is 5~5.5.

[0032] This will help improve sintering efficiency and sinter quality, reduce SO2 concentration in flue gas, and lower emission pressure.

[0033] Further, in the embodiments of this application, the chemical composition of the ordinary sintered ore, by mass percentage, includes: TFe: 56.12%~56.51%, CaO: 10.17%~10.67%, SiO2: 5.33%~5.35%, Al2O3: 2%~2.21%, MgO: 1.39%~1.44%.

[0034] Furthermore, in the embodiments of this application, the basicity of the ordinary sintered ore is 1.9~2.0.

[0035] Furthermore, in the embodiments of this application, the particle size of the ordinary sintered ore is 19mm~23mm.

[0036] Further, in the embodiments of this application, the chemical composition of the acidic pellets, by mass percentage, includes: TFe: 65.12%~65.52%, CaO: 0.29%~0.49%, SiO2: 4.35%~4.95%, Al2O3: 0.34%~0.54%, MgO: 0.8%~1.0%.

[0037] Furthermore, in the embodiments of this application, the basicity of the acidic pellet is 0.03~0.09.

[0038] Furthermore, in the embodiments of this application, the compressive strength of the acidic pellet is 2800N~3700N; the reduction expansion rate is 10%~15%.

[0039] This increases the proportion of acidic pellets fed into the furnace, thereby reducing the impact of SiO2 content in the mineral powder on pellet production and alleviating the problem of insufficient low-SiO2 mineral powder reserves.

[0040] 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 standards. If no corresponding national standard exists, then generally accepted international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0041] Examples 1-18 Examples 1-18 provide a furnace charge structure, the chemical composition of which, by mass percentage, includes: whole fine sintered ore: 3.94%~37.07%, ordinary sintered ore: 2.63%~55.89%, and acidic pellets: 40%~60%.

[0042] The chemical composition of the whole-mildew fine powder sinter, by mass percentage, includes: TFe: 54%~55%, CaO: 16.11%~17.11%, SiO2: 2.95%~3.35%, Al2O3: 1.0%~1.5%, MgO: 1.07%~2.07%. The drum strength of the whole-mildew fine powder sinter is 80%~90%. The reduction index of whole-mild sintered fine powder contains 95%–98% particles larger than 3.15 mm; the reduction index of whole-mild sintered fine powder contains 94%–95% particles larger than 6.3 mm; the degree of reduction of whole-mild sintered fine powder is 78%–80%; and the mass percentage of particles with a diameter of 0.074 mm in whole-mild sintered fine powder is 85%–90%. The basicity of whole-mild sintered fine powder is 5–5.5.

[0043] The chemical composition of ordinary sinter by mass percentage includes: TFe: 56.12%~56.51%, CaO: 10.17%~10.67%, SiO2: 5.33%~5.35%, Al2O3: 2%~2.2%, MgO: 1.39%~1.44%.

[0044] The basicity of ordinary sinter is 1.9~2.0. The particle size of ordinary sinter is 19mm~23mm.

[0045] The chemical composition of acidic pellets, by mass percentage, includes: TFe: 65.12%~65.52%, CaO: 0.29%~0.49%, SiO2: 4.35%~4.95%, Al2O3: 0.34%~0.54%, and MgO: 0.8%~1.0%. The basicity of acidic pellets is 0.03~0.09.

[0046] The compressive strength of acidic pellets is 2800N~3700N; the reduction expansion rate is 10%~15%.

[0047] The specific composition of the furnace charge structures provided in Examples 1-18 is shown in Table 1. The slag basicity produced after smelting using the furnace charge structures provided in Examples 1-18 is shown in Table 1. The molten droplet properties during smelting using the furnace charge structures provided in Examples 1-18 are shown in Table 2.

[0048] Table 1. Composition, grade of the furnace charge, and basicity of the slag produced in the examples and comparative examples.

[0049] Table 2 shows the properties of various droplets during smelting using the furnace charge structures provided in Examples 1-18.

[0050] Among them, T 10 —The temperature at which the shrinkage rate of the furnace charge in the height direction reaches 10%, in °C; T 40 —The temperature at which the shrinkage rate of the furnace charge in the height direction reaches 40%, in °C; △T1——T 40-T 10 The softening range of the reaction blast furnace; ℃; T S —The temperature at which the pressure difference between the upper and lower parts of the furnace charge reaches 500 Pa, in °C; T p-max —The temperature at which the furnace charge pressure differential reaches its maximum value, in °C; T d —The temperature at which the furnace charge drips, in °C; △T2——T d -T S The melting range of the reaction blast furnace, ℃; △P max —The maximum value of the furnace charge pressure difference, in Pa; S—Comprehensive Characteristic Index of Furnace Charge, kPa·℃. Its physical meaning is the integral value of the pressure difference curve over temperature, that is, the area enclosed by the pressure difference-temperature curve. The larger the value, the worse the melting drop performance of the furnace charge.

[0051] Comparative Example 1 Comparative Example 1 provides a furnace charge structure that differs from Example 1 in that it does not include all fine sintered ore. The specific chemical composition is shown in Table 1. The melting droplet properties during smelting using the furnace charge structure provided in Comparative Example 1 are shown in Table 2. The basicity of the ordinary sintered ore in Comparative Example 1 is 2.0.

[0052] The remaining steps are the same as those in Example 1 (the steps in the process), and will not be repeated here.

[0053] Comparative Example 2 Comparative Example 2 provides a furnace charge structure that differs from Example 1 in that it does not include all fine sintered ore. The specific chemical composition is shown in Table 1. The molten droplet properties during smelting using the furnace charge structure provided in Comparative Example 1 are shown in Table 2. The basicity of the ordinary sintered ore in Comparative Example 2 is 1.9.

[0054] The remaining steps are the same as those in Example 1 (the steps in the process), and will not be repeated here.

[0055] Comparative Examples 3-4 Comparative Examples 3 and 4 each provide a furnace charge structure, which differs from Example 1 in that the basicity of the added fine sintered ore is different. The basicity of the whole-fine sintered ore added in Comparative Example 3 was 4.0; The basicity of the whole fine powder sinter added in Comparative Example 4 was 7; The remaining steps are the same as those in Example 1 (the steps in the process), and will not be repeated here.

[0056] Results of comparative examples 3-4: In Comparative Example 3, the sintering utilization coefficient of the fine powder with a basicity of 4.0 was low, at only 1.1 t / m. 2 The concentration of SO2 in the exhaust gas is as high as 1300 mg / Nm3, resulting in high desulfurization and denitrification pressures and making production impossible.

[0057] In Comparative Example 4, the grade of the whole-fine sintered ore with an basicity of 7.0 was only 48.3%, resulting in an excessively low grade for use in the furnace, indicating that it was not suitable as a blast furnace feed.

[0058] Experimental conclusion: As can be seen from the comparative examples and comparative embodiments: 1) By adopting the furnace charge structure provided in this application, and by using a fully alkaline fine powder sinter with an basicity of 5.0 to 5.5, the proportion of acidic pellets in the furnace charge can exceed 40%, while maintaining the grade of the furnace charge at over 60%, thus effectively reducing the blast furnace coke ratio. Furthermore, this furnace charge structure exhibits good low-temperature pulverization, reducibility (the low-temperature pulverization of fully alkaline fine powder sinter is superior to that of ordinary sinter, and the reducibility is similar to that of ordinary sinter, but higher than that of acidic pellets) and melting drop performance during smelting. This undoubtedly breaks through the limitation that the development of high-proportion pellet blast furnace smelting technology must use alkaline pellets.

[0059] 2) By adopting the furnace charge structure provided in this application, the proportion of acidic pellets fed into the furnace can be increased, thereby reducing the impact of SiO2 content of mineral powder on pellet production and alleviating the problem of insufficient low-SiO2 mineral powder reserves.

[0060] In summary, this invention provides a furnace charge structure whose chemical composition includes: 3.94%~37.07% pure sinter, 2.63%~55.89% ordinary sinter, and 40%~60% acidic pellets; by mass percentage, the chemical composition of the pure sinter includes: TFe: 54%~55%, CaO: 16.11%~17.11%, SiO2: 2.95%~3.35%, Al2O3: 1.0%~1.5%, and MgO: 1.07%~2.07%; the reduction pulverization index of the pure sinter is... The total fine sintered ore with a particle size greater than 3.15 mm accounts for 95%~98%; the total fine sintered ore with a particle size greater than 6.3 mm accounts for 94%~95% of the reduction pulverization index; the reduction degree of the total fine sintered ore is 78%~80%. This allows for a blast furnace grade exceeding 60% while maintaining an acidic pellet proportion exceeding 40%, effectively reducing the blast furnace coke ratio. Furthermore, this charge structure exhibits excellent low-temperature pulverization, reduction, and dripping properties during smelting. This undoubtedly overcomes the limitation that developing high-proportion pellet blast furnace smelting technology requires the use of alkaline pellets. In addition, adopting the charge structure provided in this application increases the proportion of acidic pellets fed into the furnace, thereby reducing the impact of SiO2 content in the ore powder on pellet production and alleviating the problem of insufficient low-SiO2 ore powder reserves.

[0061] 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 furnace charge structure, characterized in that, The chemical composition of the furnace charge structure, by mass percentage, includes: whole fine sinter: 3.94%~37.07%, ordinary sinter: 2.63%~55.89%, and acidic pellets: 40%~60%. The chemical composition of the whole fine powder sintered ore, by mass percentage, includes: TFe: 54%~55%, CaO: 16.11%~17.11%, SiO2: 2.95%~3.35%, Al2O3: 1.0%~1.5%, MgO: 1.07%~2.07%.

2. The furnace charge structure according to claim 1, characterized in that, The drum strength of the fine sintered ore is 80%~90%; and / or, In the reduction pulverization index of the whole-mil fine sinter, the whole-mil fine sinter with a particle size greater than 3.15 mm accounts for 95%~98%; in the reduction pulverization index of the whole-mil fine sinter, the whole-mil fine sinter with a particle size greater than 6.3 mm accounts for 94%~95%; and / or, The reducibility of the whole fine powder sintered ore is 78%~80%.

3. The furnace charge structure according to claim 2, characterized in that, The mass percentage of particles with a diameter of 0.074 mm in the whole fine sintered ore is 85%~90%.

4. The furnace charge structure according to claim 3, characterized in that, The basicity of the whole fine powder sintered ore is 5~5.

5.

5. The furnace charge structure according to claim 1, characterized in that, The chemical composition of the ordinary sinter, by mass percentage, includes: TFe: 56.12%~56.51%, CaO: 10.17%~10.67%, SiO2: 5.33%~5.35%, Al2O3: 2%~2.21%, and MgO: 1.39%~1.44%.

6. The furnace charge structure according to claim 1, characterized in that, The basicity of the ordinary sintered ore is 1.9~2.

0.

7. The furnace charge structure according to claim 6, characterized in that, The particle size of the ordinary sintered ore is 19mm~23mm.

8. The furnace charge structure according to claim 7, characterized in that, The chemical composition of the acidic pellets, by mass percentage, includes: TFe: 65.12%~65.52%, CaO: 0.29%~0.49%, SiO2: 4.35%~4.95%, Al2O3: 0.34%~0.54%, and MgO: 0.8%~1.0%.

9. The furnace charge structure according to claim 8, characterized in that, The alkalinity of the acidic pellets is 0.03~0.

09.

10. The furnace charge structure according to claim 9, characterized in that, The compressive strength of the acidic pellets is 2800N~3700N; the reduction expansion rate is 10%~15%.

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