Method for reducing the accumulation in the center of the furnace during blast furnace smelting of high-titanium vanadium-titanium magnetite

Abstract

The present invention discloses a method for reducing the accumulation in the center of the furnace during blast furnace smelting of high-titanium vanadium-titanium magnetite, comprising: in the process of blast furnace smelting, formulating an air supply system: determining the standard wind speed according to the slag-iron ratio, the TiO2 content of the slag and the Ti content of the molten iron; calculating the actual air volume entering the blast furnace according to the standard wind speed; comparing the actual air volume entering the blast furnace with the air volume statistically calculated during production, adjusting the air intake area and the actual wind speed; in the process of blast furnace smelting, formulating a charging system: the distance between the edge of the iron-containing furnace charge and the throat steel brick is 0.32-0.48m, the distance between the coke and the throat steel brick is 0.18-0.36m, and the distance between the edge of the coke and the furnace wall is less than the ore. The method of the present invention improves the activity of the center of the blast furnace hearth, and the center temperature of the furnace bottom, one of the important indicators for characterizing the accumulation in the center of the hearth, gradually increases; the smelting intensity of the blast furnace is improved, the smelting cycle is accelerated, and the furnace temperature is reduced.

Description

Technical Field

[0001] The invention belongs to the field of blast furnace ironmaking, and specifically relates to a method for smelting high-titanium vanadium-titanium magnetite in a blast furnace, and more specifically, relates to a method for reducing accumulation in the center of a furnace during blast furnace smelting of high-titanium vanadium-titanium magnetite. Background Art

[0002] Most of the vanadium-titanium magnetites in the Panzhihua area are high-titanium vanadium-titanium magnetites with low TFe (total iron) grade and high TiO2 content. After the mineral processing process, V and Ti are isomorphously present in the iron concentrate. Therefore, there are problems in blast furnace smelting, such as high slag-to-iron ratio, high TiO2 content in slag, and easy thickening of slag.

[0003] The slag has a high TiO2 content and is easily reduced to form TiC, TiN and its solid solution Ti(C,N) during the smelting process; under blast furnace smelting conditions, this is a high-melting-point phase that cannot be melted. In severe cases, TiC, TiN and its solid solution Ti(C,N) are mixed with slag iron in the blast furnace, especially in the center of the furnace, and cannot be discharged from the blast furnace from the iron mouth in time. The volume gradually increases to form an extremely viscous mixture, thus forming a furnace accumulation. These deposits rich in TiC, TiN and their solid solution Ti(C,N) are extremely harmful to the stable operation of the blast furnace and the intensification of smelting. Reducing the formation of these deposits and discharging them out of the furnace is the basis for maintaining the stable operation of high-titanium vanadium-titanium magnetite in blast furnace smelting and further improving the smelting intensity.

[0004] Although TiO2 in the slag will inevitably be reduced during the blast furnace smelting process, as long as the generated Ti(C,N) can be controlled to an appropriate level and the slag iron is prevented from not flowing in a local area for a long time, thereby causing the gradual enrichment of Ti(C,N), the formation of deposits rich in Ti(C,N) can be avoided. The center of the furnace is the area in the blast furnace that is most difficult for heat and kinetic energy to reach. It is also the area where the slag iron temperature is extremely easy to drop and the generated Ti(C,N) is extremely easy to enrich to form viscous deposits. The formation of deposits in this area is the most harmful to the stable and smooth operation of the blast furnace and the difficulty of furnace conditions.

[0005] Based on the above, it is necessary to develop a method for reducing the accumulation in the center of the furnace during blast furnace smelting of high-titanium vanadium-titanium magnetite. Summary of the invention

[0006] The purpose of the present invention is to reduce the formation of deposits rich in TiC, TiN and their solid solution Ti(C, N) in the center of the furnace during the blast furnace smelting process of high-titanium vanadium-titanium magnetite, maintain the stable and smooth blast furnace smelting of high-titanium vanadium-titanium magnetite and further improve the blast furnace smelting intensity.

[0007] Based on this, it is necessary to adopt the following technical solutions for the above technical problems:

[0008] The present invention provides a method for reducing the accumulation in the center of the furnace during blast furnace smelting of high-titanium vanadium-titanium magnetite. The blast furnace comprises a furnace throat, a furnace body, a furnace waist, a furnace belly, a furnace hearth and a furnace bottom from top to bottom along its axial direction. A layer of radial tuyere is evenly distributed in the furnace hearth along the circumference of the blast furnace. The method reduces the accumulation in the center of the furnace hearth by adopting a reasonable air supply system and a charging system, comprising:

[0009] In the process of blast furnace smelting, formulate the air supply system:

[0010] Determine the standard wind speed based on the slag-iron ratio, the TiO2 content in the slag and the Ti content in the molten iron;

[0011] The actual air volume entering the blast furnace calculated based on the standard wind speed;

[0012] Compare the actual air volume entering the blast furnace with the air volume counted during production, and adjust the air inlet area and actual wind speed;

[0013] During the blast furnace smelting process, a charging system is formulated: the distance between the edge of the iron-containing charge and the throat steel brick is 0.32-0.48m, the distance between the coke and the throat steel brick is 0.18-0.36m, and the distance between the edge of the coke and the furnace wall is smaller than that of the ore.

[0014] In some embodiments, the blast furnace has an effective volume of 1200m 3 And above blast furnace.

[0015] In some embodiments, the blast furnace has an effective volume of 1200m 3 、1350m 3 、1750m 3 and 2000m 3 blast furnace.

[0016] In some embodiments, 2 to 4 rings of material are used for loading, and the angle difference between the outer ring of the ore and the outer focus is controlled at -0.5 to -1.0°, and the angle difference between the inner ring of the ore and the inner focus is controlled at 5.5 to 6.0°.

[0017] In some embodiments, "determine the standard wind speed according to the slag-iron ratio, the TiO2 content of the slag and the Ti content of the molten iron" is determined according to the following formula (1):

[0018] V=a×D h +b×R slag +c×(TiO2) / Ti(1)

[0019] In formula (1), V is the standard wind speed, m / s; D h is the furnace diameter, m; R slagis the slag-iron ratio, kg / t; (TiO2) is the TiO2 content in the slag, %; Ti is the Ti content in the molten iron, %; a, b, c are coefficients, a is 27~28, b is -0.17~-0.19, and c is 0.52~0.58.

[0020] In some embodiments, the coefficients a, b and c in formula (1) simultaneously take larger values ​​or smaller values ​​within the value range.

[0021] In some embodiments, the effective volume is 1200m 3 For a blast furnace with a throat diameter of 6.0m, the distance from the edge of the iron-containing charge to the throat steel brick is 0.32-0.38m, the distance from the coke to the throat steel brick is 0.18-0.28m, and the distance from the edge of the coke to the furnace wall is smaller than that of the ore.

[0022] In some embodiments, the effective volume is 1350m 3 The blast furnace has a throat diameter of 6.3m, the distance between the edge of the iron-containing charge and the throat steel brick is 0.33-0.40m, the distance between the coke and the throat steel brick is 0.19-0.30m, and the distance between the edge of the coke and the furnace wall is smaller than that of the ore.

[0023] In some embodiments, the effective volume is 1750m 3 The blast furnace has a throat diameter of 6.9m, the distance between the edge of the iron-containing charge and the throat steel brick is 0.37-0.43m, the distance between the coke and the throat steel brick is 0.21-0.32m, and the distance between the edge of the coke and the furnace wall is smaller than that of the ore.

[0024] In some embodiments, the effective volume is 2000m 3 The blast furnace has a throat diameter of 7.6m, the distance between the edge of the iron-containing charge and the throat steel brick is 0.40-0.48m, the distance between the coke and the throat steel brick is 0.23-0.36m, and the distance between the edge of the coke and the furnace wall is smaller than that of the ore.

[0025] The present invention has the following beneficial technical effects:

[0026] After the method of reducing the accumulation in the center of the hearth during blast furnace smelting of high-titanium vanadium-titanium magnetite of the present invention is implemented, the activity of the center of the hearth of the blast furnace is improved, and the center temperature of the furnace bottom, one of the important indicators characterizing the accumulation in the center of the hearth, gradually increases; the smelting intensity of the blast furnace is improved, the smelting cycle is accelerated, and the furnace temperature is reduced; every 100 times of iron tapping, the Ti and Si contents of the molten iron decrease, and the difference between the Ti content and the Si content of the molten iron, Ti-Si, is 0.01-0.065%. DETAILED DESCRIPTION

[0027] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the embodiments of the present invention are further described in detail below in conjunction with specific embodiments.

[0028] The blast furnace is composed of the throat, body, waist, belly, hearth and bottom along its axis from top to bottom. A layer of radial tuyere is evenly distributed along the circumference of the blast furnace in the hearth. The accumulation in the center of the hearth is reduced by adopting a reasonable air supply system and charging system.

[0029] Lowering the reaction temperature and shortening the reaction time are important measures to reduce the formation of Ti(C,N), and a reasonable air supply system can transfer heat and kinetic energy to the center of the hearth in a timely manner, which has a positive effect on reducing the formation of deposits in the hearth center and gradually eliminating them before they cause serious adverse effects on the blast furnace. The heat income and hearth area kinetic energy in the blast furnace mainly come from the hearth gas produced by the blast in front of the tuyere in the hearth and the combustion of coke and injected coal. A reasonable air supply system is a key factor in the production process to transfer heat and kinetic energy to the center of the hearth in a timely manner. Under the condition that the number and length of the tuyere have been determined, adjusting the air inlet area, air volume, and air temperature according to different raw material conditions is the key to achieving an active hearth center. Combined with a suitable charging system and thermal system, the stable and high-intensity smelting of a high-titanium vanadium-titanium magnetite blast furnace can be achieved.

[0030] The specific steps include:

[0031] (1) Based on the raw fuel consumption and chemical composition, calculate the actual air volume entering the furnace under standard conditions, that is, the air volume counted during production.

[0032] (2) The wind speed calculated during production is obtained from the air inlet area, the air volume calculated during production, etc.

[0033] (3) Determine the standard wind speed according to different raw material conditions. 3 、1350m 3 、1750m 3 and 2000m 3 For blast furnaces, the standard wind speed can be determined according to the following formula:

[0034] V=a×D h +b×R slag +c×(TiO2) / Ti(1)

[0035] In formula (1), V is the standard wind speed, m / s; D h is the furnace diameter, m; R slagis the calculated slag-iron ratio, kg / t; (TiO2) is the TiO2 content in the slag, %; Ti is the Ti content in the molten iron, %; a, b, c are coefficients, a is 27~28, b is -0.17~-0.19, c is 0.52~0.58, a, b, c can take larger or smaller values ​​at the same time, such as when a and c are 27 and 0.52 respectively, b takes -0.19, when a and c are 28 and 0.58 respectively, c takes -0.17.

[0036] The actual air volume entering the blast furnace is calculated based on the standard wind speed; the actual air volume entering the blast furnace is compared with the air volume counted during production, and the air inlet area and the actual wind speed are adjusted; the air volume and slag-iron ratio are obtained according to the method of the existing technical document "Ironmaking Calculation Analysis" 2010 edition pages 6 to 43.

[0037] When the above method is adopted to adjust the air supply system, a charging system that appropriately promotes the development of coal gas flow at the edge of the block-shaped material column should be adopted accordingly. 3 The blast furnace has a throat diameter of 6.0m. According to the results of the material flow trajectory measurement, at different material lines, the distance between the edge of the iron-containing furnace charge and the throat steel brick is 0.32-0.38m, the distance between the coke and the throat steel brick is 0.18-0.28m, and the distance between the edge of the coke and the furnace wall is less than that of the ore. The effective volume is 1350m 3 The blast furnace has a throat diameter of 6.3m, the distance between the edge of the iron-containing charge and the throat brick is 0.33-0.40m, the distance between the coke and the throat brick is 0.19-0.30m, and the distance between the edge of the coke and the furnace wall is less than that of the ore. The effective volume is 1750m 3 The blast furnace has a throat diameter of 6.9m, the distance between the edge of the iron-containing charge and the throat brick is 0.37-0.43m, the distance between the coke and the throat brick is 0.21-0.32m, and the distance between the edge of the coke and the furnace wall is less than that of the ore. The effective volume is 2000m 3 The blast furnace has a throat diameter of 7.6m, the distance between the edge of the iron-containing charge and the throat steel brick is 0.40-0.48m, the distance between the coke and the throat steel brick is 0.23-0.36m, and the distance between the edge of the coke and the furnace wall is smaller than that of the ore.

[0038] Example 1 :

[0039] The effective volume is 1750m 3 For a blast furnace with a hearth diameter of 9.5 m, under the conditions of a slag-iron ratio of 540 kg / t, a TiO2 content of about 22.0%, and a molten iron Ti content of about 0.185%, according to formula (1), if a, b, and c are 27, 0.52, and -0.17 and 28, 0.58, and -0.19 respectively, the standard wind speeds are 226.5 m / s and 232.4 m / s respectively.

[0040] In actual production, according to the existing technical document "Ironmaking Calculation Analysis", the actual air volume into the blast furnace is 3623m 3 / min, 549m lower than the air volume counted during production 3 / min, the pig iron output is about 4440-4500t / d, and the average Ti and Si contents of molten iron per 100 times are 0.272% and 0.241% respectively. 2 Reduced to 0.2615m 2 , under the same other conditions, according to the calculated air volume, the standard wind speed increases from 216m / s to 231m / s. At the same time, the charging system is also adjusted as shown in Tables 1 and 2. The overall charge moves toward the center, the edge of the iron-containing charge falls 0.37m from the furnace wall, and the edge of the coke falls 0.21m from the furnace wall. After adopting the above measures, the activity of the center of the blast furnace hearth is improved, and the center temperature of the furnace bottom, one of the important indicators of the accumulation of the hearth center, gradually increases from 589℃ and stabilizes between 608 and 610℃. The smelting intensity of the blast furnace is improved, the smelting cycle is accelerated, the furnace temperature is reduced, and the average content of Ti and Si in molten iron per 100 times is reduced to 0.185% and 0.129% respectively, the difference between Ti and Si content is 0.056%, and the daily output of pig iron increases to 4700-4800t / d.

[0041] Table 1 1750m 3 Blast furnace adjustment before charging system

[0042]

[0043] Table 2 1750m 3 Blast furnace charging system after adjustment

[0044]

[0045] Embodiment 2:

[0046] The effective volume is 1200m 3 For a blast furnace with a hearth diameter of 8.2 m, under the conditions of a slag-iron ratio of about 620 kg / t, a TiO2 content of about 22.0%, and a molten iron Ti content of about 0.221%, according to formula (1), if a, b, and c are 27, 0.52, and -0.19 and 28, 0.58, and -0.17 respectively, the standard wind speeds are 167.8 m / s and 169.5 m / s respectively.

[0047] In actual production, according to the existing technical document "Ironmaking Calculation Analysis", the actual air volume into the blast furnace is 2620m 3 / min, 325m lower than the air volume counted during production 3 / min, the pig iron output is about 3250-3300t / d, and the average Ti and Si contents of molten iron per 100 times are 0.230% and 0.197% respectively. 2 Reduced to 0.2600m 2 , under the same other conditions, according to the calculated air volume, the standard wind speed increases from 163m / s to 168m / s. At the same time, the charging system is also adjusted as shown in Tables 3 and 4. The overall charge moves toward the center, the edge of the iron-containing charge falls 0.33m from the furnace wall, and the edge of the coke falls 0.19m from the furnace wall. After adopting the above measures, the activity of the center of the blast furnace hearth is improved, and the center temperature of the furnace bottom, one of the important indicators of the accumulation of the hearth center, gradually increases from 478℃ and stabilizes between 505 and 510℃. The smelting intensity of the blast furnace is improved, the smelting cycle is accelerated, the furnace temperature is reduced, the Ti and Si contents of the molten iron are reduced to 0.221% and 0.168% respectively, the difference between the Ti and Si contents is 0.053%, and the daily output of pig iron increases to 3350-3400t / d.

[0048] Table 3 1200m 3 Blast furnace adjustment before charging system

[0049]

[0050] Table 4 1200m 3 Blast furnace charging system after adjustment

[0051]

[0052] Embodiment 3:

[0053] The effective volume is 1350m 3 For a blast furnace with a hearth diameter of 8.55 m, under the conditions of a slag-iron ratio of about 630 kg / t, a TiO2 content of about 22.9%, and a molten iron Ti content of about 0.187%, according to formula (1), if a, b, and c are 27, 0.52, and -0.19 and 28, 0.58, and -0.17 respectively, the standard wind speeds are 187.5 m / s and 190.8 m / s respectively.

[0054] In actual production, according to the existing technical document "Ironmaking Calculation Analysis", the actual air volume into the blast furnace is 2899m 3 / min, which is 470m lower than the air volume counted during production. 3 / min, the pig iron output is about 3500-3600t / d, and the average Ti and Si contents of molten iron per 100 times are 0.246% and 0.209% respectively. 2 Reduced to 0.2557m 2, under the same other conditions, according to the calculated air volume, the standard wind speed increases from 178.6m / s to 189m / s. At the same time, the charging system is also adjusted as shown in Tables 3 and 4. The overall charge moves toward the center, the edge of the iron-containing charge falls 0.335m from the furnace wall, and the edge of the coke falls 0.195m from the furnace wall. After adopting the above measures, the activity of the center of the blast furnace hearth is improved, and the center temperature of the furnace bottom, one of the important indicators of the accumulation in the center of the hearth, gradually increases from 525℃ and stabilizes between 537 and 543℃. The smelting intensity of the blast furnace is improved, the smelting cycle is accelerated, the furnace temperature is reduced, the Ti and Si contents of the molten iron are reduced to 0.187% and 0.125% respectively, the difference between the Ti and Si contents is 0.062%, and the daily output of pig iron increases to 3900-4000t / d.

[0055] Table 5 1350m 3 Blast furnace adjustment before charging system

[0056]

[0057] Table 6 1350m 3 Blast furnace charging system after adjustment

[0058]

[0059] In summary, the method of reducing the accumulation of the hearth center in the blast furnace smelting of high-titanium vanadium-titanium magnetite of the present invention improves the activity of the hearth center of the blast furnace after implementation, and the center temperature of the furnace bottom, one of the important indicators characterizing the accumulation of the hearth center, gradually increases, which indicates that accumulations rich in TiC, TiN and their solid solution Ti(C,N) are not formed in the hearth; this increases the smelting intensity of the blast furnace, speeds up the smelting cycle, and reduces the furnace temperature. Every 100 times of tapping, the Ti and Si content of the molten iron decreases, and the daily output of pig iron increases.

[0060] The above are exemplary embodiments disclosed in the present invention, but it should be noted that various changes and modifications may be made without departing from the scope of the embodiments disclosed in the claims. Although the elements disclosed in the embodiments of the present invention may be described or required in individual form, they may also be understood as multiple unless explicitly limited to the singular.

[0061] Those skilled in the art should understand that the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of the disclosure of the embodiments of the present invention (including the claims) is limited to these examples; under the concept of the embodiments of the present invention, the technical features in the above embodiments or different embodiments can also be combined, and there are many other changes in different aspects of the above embodiments of the present invention, which are not provided in detail for the sake of simplicity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present invention should be included in the protection scope of the embodiments of the present invention.

Claims

1. A method for reducing the accumulation in the center of the furnace during blast furnace smelting of high-titanium vanadium-titanium magnetite, characterized in that: The blast furnace is composed of the throat, body, waist, belly, hearth and bottom along its axis from top to bottom. A layer of radial tuyere is evenly distributed along the circumference of the blast furnace in the hearth. The accumulation in the center of the hearth can be reduced by adopting a reasonable air supply system and charging system, including: In the process of blast furnace smelting, formulate the air supply system: Determine the standard wind speed based on the slag-iron ratio, the TiO2 content in the slag and the Ti content in the molten iron; The actual air volume entering the blast furnace is calculated based on the standard wind speed; Compare the actual air volume entering the blast furnace with the air volume counted during production, and adjust the air inlet area and actual wind speed; During the blast furnace smelting process, a charging system is formulated: the distance between the edge of the iron-containing charge and the throat steel brick is 0.32~0.48m, the distance between the coke and the throat steel brick is 0.18~0.36m, and the distance between the edge of the coke and the furnace wall is smaller than that of the ore; Among them, "determine the standard wind speed based on the slag-iron ratio, the TiO2 content of the slag and the Ti content of the molten iron" is determined by the following formula (1): V=a×D h +b×R slag +c×(TiO2) / Ti(1) In formula (1), V is the standard wind speed, m / s; D h is the furnace diameter, m; R slag is the slag-iron ratio, kg / t; (TiO2) is the TiO2 content in the slag, %; Ti is the Ti content in the molten iron, %; a, b, c are coefficients, a is 27~28, b is -0.17~-0.19, and c is 0.52~0.58; the coefficients a, b and c can take the larger or smaller values ​​within the value range at the same time.

2. The method for reducing the accumulation in the center of the furnace during blast furnace smelting of high-titanium vanadium-titanium magnetite according to claim 1, characterized in that: The blast furnace has an effective volume of 1200m 3 And above blast furnace.

3. The method for reducing the accumulation in the center of the furnace during blast furnace smelting of high-titanium vanadium-titanium magnetite according to claim 1, characterized in that: The blast furnace has an effective volume of 1200m 3 、1350m 3 、1750m 3 and 2000m 3 blast furnace.

4. The method for reducing the accumulation in the center of the furnace during blast furnace smelting of high-titanium vanadium-titanium magnetite according to claim 1, characterized in that: Use 2 to 4 rings of material for loading, and ensure that the angle difference between the outer ring of the ore and the outer focus is controlled at -0.5 to -1.0°, and the angle difference between the inner ring of the ore and the inner focus is controlled at 5.5 to 6.0°.

5. The method for reducing the accumulation in the center of the furnace during blast furnace smelting of high-titanium vanadium-titanium magnetite according to claim 3, characterized in that: The effective volume is 1200m 3 For a blast furnace with a throat diameter of 6.0m, the distance from the edge of the iron-containing charge to the throat steel brick is 0.32~0.38m, the distance from the coke to the throat steel brick is 0.18~0.28m, and the distance from the edge of the coke to the furnace wall is smaller than that of the ore.

6. The method for reducing the accumulation in the center of the furnace during blast furnace smelting of high-titanium vanadium-titanium magnetite according to claim 3, characterized in that: The effective volume is 1350m 3 The blast furnace has a throat diameter of 6.3m, the distance between the edge of the iron-containing charge and the throat steel brick is 0.33~0.40m, the distance between the coke and the throat steel brick is 0.19~0.30m, and the distance between the edge of the coke and the furnace wall is smaller than that of the ore.

7. The method for reducing the accumulation in the center of the furnace during blast furnace smelting of high-titanium vanadium-titanium magnetite according to claim 3, characterized in that: The effective volume is 1750m 3 The blast furnace has a throat diameter of 6.9m, the distance between the edge of the iron-containing charge and the throat steel brick is 0.37~0.43m, the distance between the coke and the throat steel brick is 0.21~0.32m, and the distance between the edge of the coke and the furnace wall is smaller than that of the ore.

8. The method for reducing the accumulation in the center of the furnace during blast furnace smelting of high-titanium vanadium-titanium magnetite according to claim 3, characterized in that: The effective volume is 2000m 3 The blast furnace has a throat diameter of 7.6m, the distance between the edge of the iron-containing charge and the throat steel brick is 0.40~0.48m, the distance between the coke and the throat steel brick is 0.23~0.36m, and the distance between the edge of the coke and the furnace wall is smaller than that of the ore.

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