A method for eliminating edge accumulation of vanadium-titanium ore in blast furnace smelting

Abstract

The invention discloses a method for eliminating the edge accumulation of vanadium-titanium ore in blast furnace smelting. Aiming at the edge accumulation of furnace caused by TiC, TiN and their solid solution with high melting point and high viscosity formed when smelting vanadium-titanium ore in blast furnace, scrap steel is added into blast furnace alone or mixed with coke. When distributing, scrap steel or its mixture with coke is only distributed on the edge of furnace throat, and its distribution angle is less than or equal to the angle at which the iron-containing raw material collides with the furnace wall when a certain material line is used, and the difference with the angle is not more than 1.5°; the amount of scrap steel added is 80-100% of the theoretical TFe weight of each batch of iron-containing furnace charge when no scrap steel is added; the frequency of adding scrap steel is determined according to actual production conditions. Through the reasonable action of scrap steel, the dripping of liquid iron water on the furnace wall of blast furnace is improved to achieve the effect of flushing edge accumulation, and the technical problem of edge accumulation when smelting high-titanium vanadium-titanium ore in blast furnace is solved; thereby ensuring the stable and smooth operation of furnace conditions and improving the smelting efficiency of modern blast furnaces.

Description

Technical Field

[0001] The invention belongs to the technical field of blast furnace ironmaking, and in particular relates to a method for eliminating edge accumulation of vanadium-titanium ore in blast furnace smelting. Background Art

[0002] The slag-iron ratio of Panzhihua Iron and Steel Co., Ltd. blast furnace is high, and the TiO2 content in the slag exceeds 20%. During the smelting process, TiO2 in the slag is easily reduced to form high-melting-point phases such as TiC, TiN and its solid solution Ti(C, N) that cannot be melted under blast furnace smelting conditions, resulting in slag viscosity, which increases the difficulty of blast furnace smelting. In severe cases, TiC, TiN and its solid solution Ti(C, N) are mixed with slag in the blast furnace, especially in the furnace, and cannot be discharged from the blast furnace from the iron mouth in time. When this mixture rich in TiC, TiN and its solid solution Ti(C, N) gradually gathers and the volume gradually increases, an extremely viscous mixture is formed in the blast furnace, thereby forming a furnace accumulation. Secondly, due to the high slag-iron ratio, compared with the blast furnace of ordinary ore with high smelting grade and low slag-iron ratio, on the one hand, slag is more likely to gather in the center of the furnace, and on the other hand, the hot air blown in from the tuyere and the high-temperature coal gas formed are more difficult to reach the central area, so the Panzhihua Iron and Steel Co., Ltd. blast furnace is more likely to form a central accumulation.

[0003] For a long time, due to the characteristics of vanadium-titanium ore, Panzhihua Iron and Steel blast furnace has formed a charging system with open edge airflow and development center airflow as the main features, combined with a large air volume and large blast kinetic energy air supply system to ensure the stable operation of the blast furnace and improve the blast furnace's resistance to external factors such as sudden deterioration of coke quality and other adverse effects on high-intensity smelting. However, such an operating system requires a large amount of coke. For example, the coke ratio of Baosteel's blast furnace is less than 300kg / t, while the coke ratio of Panzhihua Iron and Steel blast furnace reaches 440-450kg / t, which is about 150kg / t higher than the advanced level.

[0004] Reducing the coke ratio is an important means to reduce blast furnace carbon emissions and pig iron costs. To this end, through the optimization of the operating system, a charging system with the main characteristics of appropriately suppressing edge airflow and developing central airflow has gradually been formed, combined with enhanced smelting technology with large blast kinetic energy and high oxygen enrichment rate, and the coke ratio has gradually decreased. However, such an operating system weakens the edge airflow and increases the risk of edge accumulation. The density of molten iron is 7.0t / m 3 , which is much larger than the density of slag (about 3.0t / m 3 ). Blast furnace production practice shows that the flushing capacity of liquid iron is much greater than that of liquid slag. In recent years, adding scrap steel to blast furnaces has gradually become one of the effective measures to increase the output and smelting intensity of low-grade blast furnaces. Tests on the soft melting performance of scrap steel show that although the C content of scrap steel is low and the melting point is high, during the soft melting process, as the carburizing reaction proceeds, the scrap steel can drip at 1200℃, and the dripping temperature is much lower than that of commonly used iron-containing furnace materials such as sintered ore and pelletized ore. Summary of the invention

[0005] In order to overcome the defects of the prior art, the present invention improves the dripping of liquid iron on the blast furnace wall through the reasonable effect of scrap steel, so as to achieve the effect of flushing the edge accumulation.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides a method for eliminating edge accumulation of vanadium-titanium ore in blast furnace smelting, comprising the following steps:

[0007] ① To judge the accumulation phenomenon in the furnace during smelting vanadium-titanium ore in a blast furnace; the judgment method includes: the blast furnace's ability to receive air volume is weakened, the air volume gradually decreases, and it cannot be restored to the normal level for a long time; the furnace throat temperature decreases; the output decreases.

[0008] ② Adding scrap steel alone or mixed with coke into the blast furnace, not adding it together with other iron-containing raw materials such as sintered ore or pelletized ore.

[0009] ③ When placing the charge, the scrap steel or its mixture with coke is placed only on the edge of the furnace throat, and its placing angle is less than or equal to the angle at which the iron-containing raw material collides with the furnace wall at a certain charge line, and the difference with this angle is not more than 1.5°. For example, the ore placing angle, from the outside of the furnace throat to the center, when the charge line is 2.0m, when the angle of the iron-containing raw material is 39°, the charge will collide with the furnace wall, then the maximum placing angle of the scrap steel or its mixture with coke is 39°, and the minimum is 37.5°.

[0010] ④ When scrap steel is added alone, the weight of each batch of scrap steel is 80% to 100% of the weight of its TFe and the theoretical weight of TFe of each batch of iron-containing furnace charge when no scrap steel is added; correspondingly, after the scrap steel is added, the next batch of coke should be added immediately, according to the ratio of the theoretical weight of TFe of each batch of ore when no scrap steel is added to the coke load (the ratio of the total weight of ore to the total weight of coke, coke includes the coke added alone and the small-particle coke mixed with the ore), and the corresponding weight of coke is added to the batch of coke after calculation.

[0011] When scrap steel and coke are mixed and added, the amount of scrap steel added is still 80% to 100% of the theoretical TFe weight of each batch of iron-containing furnace charge when no scrap steel is added, and the weight of the coke mixed with it is calculated according to the ratio of the theoretical TFe weight of each batch of ore when no scrap steel is added to the coke load (the ratio of the total weight of ore to the total weight of coke, the coke includes the coke added separately and the small-particle coke mixed with the ore).

[0012] ⑤ Determine the frequency of adding scrap steel according to the edge accumulation degree determined in step ①, and scrap steel can be added once every 5 batches, 10 batches or 30 batches; each batch of materials includes adding iron-containing raw materials once and coke once.

[0013] An application of the above method in blast furnace smelting.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] Aiming at the accumulation at the edge of the furnace caused by TiC, TiN and their solid solution mixtures with high melting points and high viscosity formed when smelting high-titanium vanadium-titanium ore in a blast furnace, the present invention adopts a unique process mode, and adds scrap steel alone or mixed with coke into the blast furnace, and does not use it together with iron-containing raw materials such as sintered ore, pelletized ore or lump ore; the amount of scrap steel added is still 80-100% of the theoretical TFe weight of each batch of iron-containing furnace charge when no scrap steel is added; thus, the problem of accumulation at the edge of the furnace when smelting high-titanium vanadium-titanium ore in a blast furnace is solved. DETAILED DESCRIPTION

[0016] The present invention is further described below in conjunction with specific examples, but the present invention is not limited in any way. To avoid redundant description, the raw materials in the following examples are all commercially available unless otherwise specified, and the methods used are all conventional methods unless otherwise specified.

[0017] Example 1

[0018] The effective volume is 1750m 3 The charging system of the blast furnace is shown in Table 1. The charging grade is 51.48%, and the coke load is 4.46t / t, that is, 41.5 / (8.5+0.8)=4.46.

[0019] Table 1 1750m 3 Blast furnace charging system

[0020]

[0021] A method for eliminating edge accumulation of vanadium-titanium ore during blast furnace smelting comprises the following steps:

[0022] ① To judge the accumulation phenomenon at the edge of the furnace during the smelting of vanadium-titanium ore in the blast furnace; due to the accumulation of the furnace, the blast furnace air volume is reduced from 4150m 3 / min reduced to 3920m 3 / min, the throat temperature dropped from 120℃ to 87℃, and the output dropped from 4521 tons / day to 4120 tons / day. It can be judged that the accumulation on the edge of the furnace has occurred, and measures should be taken to eliminate it.

[0023] ② Adding scrap steel alone or mixed with coke into the blast furnace, not adding it together with other iron-containing raw materials such as sintered ore or pelletized ore;

[0024] ③ When placing the material, the scrap steel or its mixture with coke is placed only on the edge of the furnace throat, and the placing angle is less than or equal to the angle at which the iron-containing raw material collides with the furnace wall at a certain material line, and the difference from the angle is not more than 1.5°;

[0025] ④ When adding scrap steel individually, the weight of each batch of scrap steel added in a centralized manner shall be calculated based on the ratio of the TFe weight of each batch of scrap steel to the theoretical TFe weight of each batch of iron-containing furnace charge without adding scrap steel, which is 80-100%; correspondingly, when adding scrap steel, the next batch of coke shall be added immediately after adding the scrap steel, and the corresponding coke weight shall be added to the batch of coke after calculation based on the ratio of the theoretical TFe weight of each batch of ore without adding scrap steel to the coke load;

[0026] When scrap steel is mixed with coke, the amount of scrap steel added is still 80%-100% of the theoretical TFe weight of each batch of iron-containing furnace charge when no scrap steel is added, and the weight of coke mixed with it is calculated by the ratio of the theoretical TFe weight of each batch of ore when no scrap steel is added to the coke load;

[0027] ⑤ According to the edge accumulation degree determined in step ①, the frequency of adding scrap steel can be determined. Scrap steel can be added once every 5 batches, 10 batches or 30 batches.

[0028] In the above steps ② to ⑤, 17.09 tons of scrap steel (accounting for 80% of TFe in each batch of iron-containing charge) are added alone, and the scrap steel distribution angle is 38°. After adding the scrap steel, 3.83 tons of coke are added to the next batch of coke immediately, that is, the batch weight of the next batch of coke is 12.33 tons / batch, and the remaining small pieces of coke 0.8 tons of iron-containing charge (sintered ore and pelletized ore) are added together, and scrap steel is added once every 10 batches of charge.

[0029] Using the above method, after adding scrap steel every 10 batches, after about 140 batches, the edge airflow was developed, the furnace throat temperature increased to 113℃, and the air volume increased from 3920m 3 / min gradually increased to 4138m 3 / min, which promptly stopped the gradual deterioration of the furnace condition caused by edge accumulation, indicating that the edge accumulation of the furnace has been eliminated.

[0030] Example 2

[0031] The effective volume is 2000m 3 The blast furnace has a charging system as shown in Table 2. The charging grade is 50.91% and the coke load is 4.36t / t.

[0032] Table 2 Blast furnace charging system

[0033] Angle (°) 42 41.5 40.5 38.5 36.5 34.0 28.0 Batch weight(t) Feed line(m) Ore(Rings) 2 3 3 3 2 2 46.69 1.8 Coke(ring number) 2 2 2 2 2 2 4 10.23 1.8

[0034] A method for eliminating edge accumulation of vanadium-titanium ore during blast furnace smelting comprises the following steps:

[0035] ① To judge the accumulation phenomenon at the edge of the furnace during the smelting of vanadium-titanium ore in the blast furnace; due to the accumulation of the furnace, the air volume is reduced from 4490m 3 / min gradually decreased to 4070m 3 / min, the output decreased from about 4930 tons / day to 4070 tons / day, and the throat temperature decreased from 137°C to 93°C. It can be judged that the accumulation at the edge of the furnace has occurred and measures should be taken to eliminate it.

[0036] ② Adding scrap steel alone or mixed with coke into the blast furnace, not adding it together with other iron-containing raw materials such as sintered ore or pelletized ore;

[0037] ③ When placing the material, the scrap steel or its mixture with coke is placed only on the edge of the furnace throat, and the placing angle is less than or equal to the angle at which the iron-containing raw material collides with the furnace wall at a certain material line, and the difference from the angle is not more than 1.5°;

[0038] ④ When adding scrap steel individually, the weight of each batch of scrap steel added in a centralized manner shall be calculated based on the ratio of the TFe weight of each batch of scrap steel to the theoretical TFe weight of each batch of iron-containing furnace charge without adding scrap steel, which is 80%-100%; correspondingly, when adding scrap steel, the next batch of coke shall be added immediately after adding the scrap steel, and the corresponding coke weight shall be added to the batch of coke after calculation based on the ratio of the theoretical TFe weight of each batch of ore without adding scrap steel to the coke load;

[0039] When scrap steel is mixed with coke, the amount of scrap steel added is still 80%-100% of the theoretical TFe weight of each batch of iron-containing furnace charge when no scrap steel is added, and the weight of coke mixed with it is calculated by the ratio of the theoretical TFe weight of each batch of ore when no scrap steel is added to the coke load;

[0040] ⑤ According to the edge accumulation degree determined in step ①, the frequency of adding scrap steel can be determined. Scrap steel can be added once every 5 batches, 10 batches or 30 batches.

[0041] In the above steps ② to ⑤, the scrap steel and coke were mixed and added to the blast furnace, the weight of the scrap steel and coke were 21.39 tons (90% of the theoretical TFe of the ore) and 4.90 tons, respectively, and the feeding angle was 42°. The mixture of scrap steel and coke was added once every 20 batches.

[0042] Using the above method, a mixture of scrap steel and coke was added every 20 batches. After about 280 batches, the blast furnace air volume was restored to 4468m 3 / min, the output increased to 4898 tons / day, and the throat temperature increased to 139℃, indicating that the accumulation on the edge of the furnace hearth had been eliminated.

[0043] Example 3

[0044] The effective volume is 12000m 3 The blast furnace has a charging system as shown in Table 3. The charging grade is 50.64% and the coke load is 4.37t / t.

[0045] Table 3 Blast furnace charging system

[0046]

[0047] A method for eliminating edge accumulation of vanadium-titanium ore during blast furnace smelting comprises the following steps:

[0048] ① To judge the accumulation phenomenon at the edge of the furnace during the smelting of vanadium-titanium ore in the blast furnace; due to the formation of edge accumulation, the blast furnace air volume is increased from 2940m 3 / min gradually decreased to 2420m 3 / min, pig iron output decreased from 3450 tons / day to 3000 tons / day, furnace throat temperature decreased from 158℃ to 89℃, and accumulation on the edge of the furnace hearth has occurred, which should be eliminated.

[0049] ② Adding scrap steel alone or mixed with coke into the blast furnace, not adding it together with other iron-containing raw materials such as sintered ore or pelletized ore;

[0050] ③ When placing the material, the scrap steel or its mixture with coke is placed only on the edge of the furnace throat, and the placing angle is less than or equal to the angle at which the iron-containing raw material collides with the furnace wall at a certain material line, and the difference from the angle is not more than 1.5°;

[0051] ④ When adding scrap steel individually, the weight of each batch of scrap steel added in a centralized manner shall be calculated based on the ratio of the TFe weight of each batch of scrap steel to the theoretical TFe weight of each batch of iron-containing furnace charge without adding scrap steel, which is 80%-100%; correspondingly, when adding scrap steel, the next batch of coke shall be added immediately after adding the scrap steel, and the corresponding coke weight shall be added to the batch of coke after calculation based on the ratio of the theoretical TFe weight of each batch of ore without adding scrap steel to the coke load;

[0052] When scrap steel is mixed with coke, the amount of scrap steel added is still 80%-100% of the theoretical TFe weight of each batch of iron-containing furnace charge when no scrap steel is added, and the weight of coke mixed with it is calculated by the ratio of the theoretical TFe weight of each batch of ore when no scrap steel is added to the coke load;

[0053] ⑤ According to the edge accumulation degree determined in step ①, the frequency of adding scrap steel can be determined. Scrap steel can be added once every 5 batches, 10 batches or 30 batches.

[0054] In the above steps ② to ⑤, 13.93 tons of scrap steel (accounting for 100% of TFe in each batch of iron-containing furnace charge) are added alone, and the scrap steel distribution angle is 38.5°. After adding the scrap steel, 3.19 tons of coke are immediately added to the next batch of coke, that is, the batch weight of the next batch of coke is 8.99 tons / batch, and the remaining small pieces of coke 0.5 tons of iron-containing furnace charge (sintered ore and pelletized ore) are added together. Scrap steel is added once every 15 batches.

[0055] Using the above method, scrap steel was added every 15 batches. After about 90 batches, the air volume returned to normal and the throat temperature returned to 146°C, indicating that the accumulation on the edge of the furnace had been eliminated.

[0056] For any technician familiar with the art, without departing from the scope of the technical solution of the present invention, the technical content disclosed above can be used to make many possible changes and modifications to the technical solution of the present invention, or modified into equivalent embodiments with equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention should still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for eliminating edge accumulation of vanadium-titanium ore in blast furnace smelting, characterized in that: The method comprises the following steps: ① To judge the accumulation phenomenon on the edge of the furnace during the smelting of vanadium-titanium ore in the blast furnace; The judgment method includes the blast furnace's ability to receive air volume weakening, the air volume gradually decreasing, and being unable to return to normal levels for a long time; The judgment method includes the reduction of furnace throat temperature; Methods of judgment include reduction in production; ② Adding scrap steel alone or mixed with coke into the blast furnace, but not adding it together with sintered ore or pelletized ore; ③ When placing the material, the scrap steel or its mixture with coke is placed on the edge of the furnace throat, and the placing angle is less than or equal to the angle at which the iron-containing raw material collides with the furnace wall at a certain material line, and the difference from the angle is not more than 1.5°; ④ When adding scrap steel alone, the weight of each batch of scrap steel is calculated based on its TFe weight being 80% to 100% of the theoretical TFe weight of each batch of iron-containing furnace charge without adding scrap steel; correspondingly, when adding coke in the next batch immediately after adding scrap steel, the corresponding coke weight is added to the batch of coke by calculating the ratio of the theoretical TFe weight of each batch of ore without adding scrap steel to the coke load; When scrap steel is mixed with coke, the amount of scrap steel added is still 80% to 100% of the theoretical TFe weight of each batch of iron-containing furnace charge when no scrap steel is added, and the weight of coke mixed with it is calculated by the ratio of the theoretical TFe weight of each batch of ore when no scrap steel is added to the coke load; The coke load is the ratio of the total weight of the ore to the total weight of the coke, and the coke includes the coke added separately and the small-size coke mixed with the ore; ⑤ Determine the frequency of adding scrap steel according to the edge accumulation degree determined in step ①, adding scrap steel once every 5 batches, 10 batches or 30 batches; Each batch includes a charge of iron-containing raw materials and a charge of coke.

2. Application of the method as claimed in claim 1 in blast furnace smelting.

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