Method for reducing splashing of high-titanium molten iron smelted by converter

Abstract

The invention relates to a method for reducing splashing of high-titanium molten iron smelted by a converter, and belongs to the technical field of converter smelting, in a blowing process, an oxygen lance system and a feeding system are controlled, and the oxygen lance system is as follows: in the initial smelting stage of 0-3 minutes, the height of an oxygen lance is controlled to be 1.2-1.4 m, and blowing is started; in the middle stage of converter smelting for 3-9 min, the height of the oxygen lance is increased to 1.4-1.5 m; in the later stage of converter smelting for 9-14 min, the height of an oxygen lance is reduced to 1.1-1.3 m for blowing in 9-10 min; the height of the oxygen lance is controlled to be between 1.0 m and 1.6 m for 10-11 minutes, the oxygen lance is pressed when the height of the oxygen lance is between 0.9 m and 1.1 m for 11-14 minutes, and the oxygen lance is lifted until oxygen blowing is finished; the feeding system is as follows: 1000 kg of light-burned dolomite is added at the initial stage of smelting for 0-2 min, 500 kg of lime is added 30 s after the light-burned dolomite is added, 500 kg of lime or light-burned dolomite is alternately added every 0.5-1.5 min in the subsequent smelting process of 2-9 min, and 1000-2300 kg of slag particles are added at the final stage of converter smelting until oxygen blowing smelting is finished. The splashing rate is reduced to 30%, and the splashing amount is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of converter smelting and relates to a method for reducing splashing of high-titanium molten iron in converter smelting. Background Art

[0002] Converter steelmaking is an important smelting process that is widely used in the field of steel production. It involves adding pig iron or scrap steel with an appropriate amount of scrap steel, ferroalloys, etc. in a specific device, blowing oxygen into the furnace to oxidize and remove harmful impurities in the charge, and adding an appropriate amount of alloying elements to adjust the composition of the steel and improve its quality.

[0003] At present, most steel companies add titanium ore during blast furnace ironmaking to form TiN or Ti(C,N) in the iron bath of the blast furnace, and deposit it on the working surface of the furnace or the brick seams to protect the furnace, which also leads to a significant increase in the average titanium mass fraction in the molten iron. Since Ti has a stronger ability to bind O than elements such as Si, Mn, and P, the Ti in the molten iron in the early stage of converter smelting is oxidized and enters the slag, resulting in a high TiO2 content in the slag. At the same time, titanium oxide (TiO2) is acidic in the slag, so TiO2 is easily released by the basic oxides in the slag. 2- Combine to form composite anion TiO4 4- 、Ti2O7 6- These anions will combine into larger anion clusters, increasing the viscosity of the slag. Since the heat added by Ti in the molten iron is almost equal to that of Si, it is very easy to cause a rapid increase in the early temperature. Therefore, the more violent CO reaction makes it easy to splash when the converter smelts high-titanium molten iron, and the dry-out is serious in the middle and late stages, the furnace mouth is easy to stick to the slag, and the P removal effect is poor. The acidic titanium oxide will neutralize the alkaline CaO and aggravate the corrosion of the furnace lining. In order to protect the furnace lining and achieve the target alkalinity, the amount of slag used needs to be increased. These problems will lead to an increase in the consumption of steel materials and slag, and also seriously restrict the improvement of the production rhythm. Summary of the invention

[0004] The present invention aims to adjust converter smelting process parameters according to the Ti element content in molten iron at the converter smelting site and the number and size of splashing during converter smelting, and to formulate a reasonable converter smelting process system.

[0005] At present, the splashing rate of high-titanium molten iron in the 150t converter of the steel plant is about 70%, which will cause serious economic losses. Therefore, it is necessary to formulate a smelting system specifically for smelting high-titanium molten iron, including oxygen lance system, feeding system and slag retention system.

[0006] The technical solution adopted by the present invention to achieve its purpose is as follows:

[0007] A method for reducing splashing of high-titanium molten iron in a converter, wherein the oxygen lance system and the feeding system are controlled in the blowing process, wherein:

[0008] The oxygen lance system is as follows: in the initial stage of smelting from 0 to 3 minutes, the oxygen lance height is controlled between 1.2m and 1.4m, and blowing begins; in the middle stage of converter smelting from 3 to 9 minutes, the oxygen lance height is raised to between 1.4m and 1.5m; in the late stage of converter smelting from 9 to 14 minutes, the oxygen lance height is lowered to between 1.1m and 1.3m for blowing from 9 to 10 minutes; the oxygen lance height is controlled to change between 1.0m and 1.6m from 10 to 11 minutes, and the oxygen lance height is pressed at 0.9m to 1.1m from 11 to 14 minutes until the oxygen blowing is finished, and the lance is raised;

[0009] The feeding system is as follows: 900-1000kg of light-burned dolomite is added at the initial stage of smelting (0-2min). There is a large amount of TiO2 in the high-titanium iron water. MgO can react with TiO2 to form MgTiO3, which has good fluidity and reduces the probability of splashing in the early stage. 450-500kg of lime is added 30s after adding the light-burned dolomite. In the subsequent smelting process of 2-9min, 400-600kg of lime or light-burned dolomite is added alternately. At the end of the converter smelting (12-13min), 1000-2300kg of magnetic separation slag particles are added until the oxygen blowing smelting is completed.

[0010] It should be noted that in the early stage of blowing (0-3 minutes), the slag basicity should be controlled at 1.2-1.5, and in the later stage of blowing (9-14 minutes), the slag basicity R should be controlled between 2.8 and 3.2.

[0011] Furthermore, when the mass fraction of Ti in high-titanium molten iron is above 0.12%, the double slag method is adopted, the slag after desiliconization and detitaniumization is poured out and slag is made again; when the mass fraction of Ti in molten iron is below 0.12%, the single slag method is adopted for converter smelting, and attention should be paid to temperature control.

[0012] The beneficial effects of the present invention are:

[0013] The present invention achieves the purpose of reducing converter splashing. Compared with the prior art, the method of the present invention can reduce the splashing rate to 30% and the splashing amount by smelting high-titanium molten iron, thereby reducing smelting economic losses, reducing the probability of casualties, and reducing the degree of pollution to the atmosphere caused by splashing. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is the oxygen lance control curve of Example 1.

[0015] Figure 2 This is the oxygen lance control curve of Example 2.

[0016] Figure 3 This is the oxygen lance control curve of Example 3. DETAILED DESCRIPTION

[0017] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0018] Example 1

[0019] Oxygen lance system: see Figure 1 ,according to Figure 1 Oxygen lance control curve operation.

[0020] The feeding system is shown in Table 1.

[0021] Table 1 Feeding time and feeding amount

[0022]

[0023]

[0024] There was no obvious splashing and the metal recovery rate was 95%.

[0025] Example 2

[0026] Oxygen lance system: see Figure 2 ,according to Figure 2 The oxygen gun control curve operation and feeding system are shown in Table 2.

[0027] Table 2 Feeding time and feeding amount

[0028] Feeding time Feeding amount / kg Slag type 1min50s 920 Lightly burned dolomite 2min20s 500 lime 3min50s 500 Lightly burned dolomite 4min50s 486 lime 5min40s 500 Lightly burned dolomite 6min50s 500 lime 7min30s 490 Lightly burned dolomite 8min40s 500 lime 9min00s 560 Lightly burned dolomite 12min30s 1000 Slag

[0029] There was no obvious splashing and the metal recovery rate was 94%.

[0030] Example 3

[0031] Oxygen lance system: see Figure 3 ,according to Figure 3 The oxygen lance control curve is operated. The feeding system is shown in Table 3.

[0032] Table 3 Feeding time and feeding amount

[0033]

[0034]

[0035] There was a small amount of splashing and the metal recovery was 90%.

Claims

1. A method for reducing splashing of high-titanium molten iron in a converter, characterized in that: In the blowing process, the oxygen lance system and the feeding system are controlled, among which, The oxygen lance system is as follows: in the initial stage of smelting from 0 to 3 minutes, the oxygen lance height is controlled between 1.2m and 1.4m, and blowing begins; in the middle stage of converter smelting from 3 to 9 minutes, the oxygen lance height is raised to between 1.4m and 1.5m; in the late stage of converter smelting from 9 to 14 minutes, the oxygen lance height is lowered to between 1.1m and 1.3m for blowing from 9 to 10 minutes; the oxygen lance height is controlled to change between 1.0m and 1.6m from 10 to 11 minutes, and the oxygen lance height is pressed at 0.9m to 1.1m from 11 to 14 minutes until the oxygen blowing is finished, and the lance is raised; The feeding system is as follows: 900-1000 kg of light-burned dolomite is added at the initial stage of smelting of 0-2 minutes, and 450-500 kg of lime is added 30 seconds after the addition of the light-burned dolomite. In the subsequent smelting process of 2-9 minutes, 400-600 kg of lime or light-burned dolomite is added alternately. At the end of the converter smelting of 12-13 minutes, 1000-2300 kg of magnetic separation slag particles are added until the oxygen blowing smelting is completed.

2. A method for reducing splashing of high-titanium molten iron in a converter according to claim 1, characterized in that: In the early stage of blowing (0-3 minutes), the slag basicity is controlled at 1.2-1.5, and in the later stage of blowing (9-14 minutes), the slag basicity R is controlled at between 2.8 and 3.

2.

3. A method for reducing splashing of high-titanium molten iron in a converter according to claim 1, characterized in that: When the mass fraction of Ti in high-titanium molten iron is above 0.12%, the double slag method is adopted, the slag after desiliconization and detitaniumization is poured out and slag is made again; when the mass fraction of Ti in molten iron is below 0.12%, the single slag method is adopted for converter smelting.

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