Semi-steel steelmaking and slagging method

Abstract

The invention relates to the technical field of steelmaking, and provides a semi-steel steelmaking slagging method which comprises the following steps: in the early stage of an oxygen blowing stage of converter smelting, spraying a powdery slagging agent onto the surface of semi-steel molten iron obtained by vanadium extraction smelting; and in the middle and later stages of the oxygen blowing stage of converter smelting, block-shaped slag formers are added into the semi-steel molten iron in batches, so that slag is obtained. According to the scheme, by adjusting the slagging constituent adding mode and technology in the converter slagging process of semi-steel steelmaking and cooperating with the oxygen blowing technology, the high efficiency and stability of the steelmaking process of the semi-steel molten steel obtained through vanadium extraction smelting are improved, the slagging speed in the steelmaking process of the semi-steel molten steel obtained through vanadium extraction smelting is increased, and the production efficiency of the semi-steel molten steel obtained through vanadium extraction smelting is improved. The quality of material slag and the quality of molten steel.

Description

Technical Field

[0001] The invention relates to the technical field of steelmaking, in particular to a semi-steel steelmaking slag making method. Background Art

[0002] By vanadium extraction and smelting to make steel, vanadium slag with high vanadium content can be obtained. Therefore, vanadium extraction and smelting are increasingly widely used in the steelmaking process. However, the semi-iron water obtained by vanadium extraction and smelting has the characteristics of low silicon (≤0.25%) and low manganese, which makes the semi-iron water difficult to slag, severe splashing, severe overoxidation, etc. during the converter smelting process. Summary of the invention

[0003] In view of this, the present invention proposes a semi-steel steelmaking slag making method, which solves the problems of difficult slag formation, severe splashing, severe overoxidation, etc. in the semi-steel steelmaking converter slag making process.

[0004] On the one hand, an embodiment of the present invention provides a semi-steel steelmaking and slag making method, comprising: In the early stage of oxygen blowing in converter smelting, a powdered slag-making agent is sprayed onto the surface of semi-iron molten steel obtained through vanadium extraction smelting; In the middle and late stages of oxygen blowing in converter smelting, a block slag-making agent is added to the semi-iron molten steel in batches to obtain slag.

[0005] In some embodiments, in the early stage of oxygen blowing in converter smelting, a powdered slag-making agent is sprayed onto the surface of semi-ferrous metal obtained through vanadium extraction smelting, comprising: During the oxygen blowing stage, 1 to 3 minutes later, a powdered slag-forming agent is sprayed onto the surface of the semi-iron water by top blowing.

[0006] In some embodiments, the added amount of the powdered slag-forming agent is (5-10) kg / t.

[0007] In some embodiments, in the middle and late stages of oxygen blowing in converter smelting, a blocky slag-making agent is added to the semi-iron molten steel in batches, comprising: At 3-8 minutes of the oxygen blowing stage, a certain amount of block slag-making agent is obtained from the converter silo, and the obtained block slag-making agent is added to the semi-iron water; At 11 minutes to 13 minutes of the oxygen blowing stage, a certain amount of block slag-forming agent is obtained from the converter silo, and the obtained block slag-forming agent is added to the semi-iron water.

[0008] In some embodiments, a certain amount of block slag-forming agent is obtained from the converter silo at 3-8 minutes of the oxygen blowing stage, including: at 3-8 minutes of the oxygen blowing stage, the amount of the block slag-forming agent added is (10-15) kg / t; At 11min~13min of the oxygen blowing stage, a certain amount of block slag-forming agent is obtained from the converter silo, including: at 11min~13min of the oxygen blowing stage, the addition amount of the block slag-forming agent is (2~5) kg / t.

[0009] In some embodiments, the powdered slag-making agent includes: any one or more of lime powder, limestone powder, dolomite powder and light-burned dolomite powder; The massive slag-forming agent includes any one or more of lime, limestone, dolomite and light-burned dolomite.

[0010] In some embodiments, the particle size of the powdered slag-forming agent is in the range of 0.01 mm to 1 mm, and the powdered slag-forming agent with a particle size in the range of 0.2 mm to 1 mm accounts for more than 70% of the total powdered slag-forming agent.

[0011] In some embodiments, the particle size of the blocky slag-forming agent is in the range of 20 mm to 50 mm.

[0012] In some embodiments, in the early stage of oxygen blowing in converter smelting, a powdered slag-making agent is sprayed onto the surface of semi-ferrous metal obtained through vanadium extraction smelting, comprising: A powdery slag-forming agent is sprayed onto the surface of the semi-iron water through a nozzle arranged in the oxygen lance, wherein the carrier gas of the powdery slag-forming agent is nitrogen or oxygen.

[0013] In some embodiments, in the early stage of oxygen blowing in converter smelting, a powdered slag-making agent is sprayed onto the surface of semi-ferrous metal obtained through vanadium extraction smelting, comprising: A powdery slag-forming agent is sprayed onto the surface of the semi-iron water through a nozzle arranged outside the oxygen lance, wherein the carrier gas of the powdery slag-forming agent is nitrogen.

[0014] The present invention has at least the following beneficial effects: The invention provides a semi-steel steelmaking slag making method. In the oxygen blowing stage of the converter slag making process of the semi-steel steelmaking, the addition of a slag making agent is carried out together with the oxygen blowing. The powdery slag making agent and the blocky slag making agent are sequentially added to the semi-steel water obtained by vanadium extraction smelting in batches at different periods of oxygen blowing. The powdery slag making agent is sprayed onto the surface of the semi-steel water obtained by vanadium extraction smelting in the early stage of oxygen blowing, so that the slag forming speed of the semi-steel water can be accelerated in the early stage of oxygen blowing. In the middle and late stages of oxygen blowing, the blocky slag making agent is added to the semi-steel water obtained by vanadium extraction smelting, so that the slag forming stability of the semi-steel water can be improved, the impurities in the finally obtained molten steel can be reduced, and the quality of the finally obtained molten steel can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other embodiments can be obtained based on these drawings without paying creative work.

[0016] Figure 1 A flow chart of a semi-steel steelmaking and slag making method provided by an embodiment of the present invention; Figure 2 A flow chart of a semi-steel steelmaking and slag making method provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0017] 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 combination with specific embodiments and with reference to the accompanying drawings.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field of the present invention; the terms used in this specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. For example, the directions or positions indicated by the terms "length", "width", "up", "down", "left", "right", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the directions or positions shown in the drawings, which are only for the convenience of description and should not be understood as limitations on the present technical solution.

[0019] The terms "including" and "having" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions; the terms "first", "second", etc. in the specification and claims of the present invention or the above-mentioned drawings are used to distinguish different objects rather than to describe a specific order. "Multiple" means two or more, unless otherwise clearly and specifically defined.

[0020] In the specification and claims of the present invention and the above-mentioned drawings, when an element is referred to as being "fixed to" or "mounted on" or "disposed on" or "connected to" another element, it may be directly or indirectly located on the other element. For example, when an element is referred to as being "connected to" another element, it may be directly or indirectly connected to the other element.

[0021] By using vanadium extraction and smelting to make steel, vanadium slag with a high vanadium content can be obtained. Therefore, vanadium extraction and smelting are increasingly widely used in the steelmaking process. However, the semi-iron water obtained by vanadium extraction and smelting has the characteristics of low silicon (≤0.25%) and low manganese.

[0022] In the related art, slag and semi-iron water with improved purity can be obtained by adding slag-forming agents to the semi-iron water obtained from vanadium extraction smelting during the converter smelting process. However, the slag-making process of the converter smelting has problems such as difficult slag formation, severe splashing, and relatively severe slag overoxidation.

[0023] In order to improve the slag-forming efficiency, the relevant technology adopts the method of adding silicon-containing substances to increase the slag volume and heat source, and promoting the slag-forming process by adopting a relatively high oxygen lance height. However, this method can easily lead to problems such as increased slag overoxidation in the converter smelting process and increased oxygen content in the molten steel obtained from the converter smelting.

[0024] The inventors have found through the above analysis that there is currently no mature converter semi-steel smelting process to solve the problems of difficult slag formation, severe splashing, and relatively severe overoxidation in the semi-steel water obtained from vanadium extraction smelting.

[0025] In view of this, in order to solve at least one of the above technical problems, the present invention proposes a slag-making method for semi-steel steelmaking. By adjusting the addition method and process of the slag-making agent in the semi-steel steelmaking converter process, and cooperating with the top blowing oxygen supply process, it can help to increase the slag-forming rate of the semi-steel water obtained by vanadium extraction smelting in the converter smelting process, reduce splashing and the oxygen content in the obtained molten steel, and improve the efficiency and stability of converter steelmaking.

[0026] The present invention is described in detail below in conjunction with embodiments and drawings.

[0027] A first aspect of an embodiment of the present invention provides a semi-steel steelmaking and slag making method, such as Figure 1 As shown, the semi-steelmaking slag making method may include steps S10-S11.

[0028] S10. In the early stage of oxygen blowing in converter smelting, a powdered slag-forming agent is sprayed onto the surface of semi-iron water obtained through vanadium extraction smelting.

[0029] S11. In the middle and late stages of oxygen blowing in converter smelting, a block slag-forming agent is added to the semi-iron molten metal in batches to obtain slag.

[0030] According to the embodiment of the present invention, in the oxygen blowing stage of the converter slag-making process of semi-steel steelmaking, the slag-forming agent is added together with the oxygen blowing, and the powdery slag-forming agent and the blocky slag-forming agent are added to the semi-steel molten iron obtained by vanadium extraction smelting in batches at different periods of oxygen blowing. In the early stage of oxygen blowing, the powdery slag-forming agent is sprayed onto the surface of the semi-steel molten iron obtained by vanadium extraction smelting, so that the slag-forming speed of the semi-steel molten iron can be accelerated in the early stage of oxygen blowing. In the middle and late stages of oxygen blowing, the blocky slag-forming agent is added to the semi-steel molten iron obtained by vanadium extraction smelting, so that the slag-forming stability of the semi-steel molten iron can be improved, the impurities in the molten steel finally obtained can be reduced, and the quality of the molten steel finally obtained can be improved.

[0031] The embodiment of the present invention can improve the efficiency and stability of the semi-iron molten steelmaking process obtained by vanadium extraction smelting by adjusting the slag-forming agent addition method and process in the converter slag-making process of semi-iron steelmaking and coordinating the oxygen blowing process, thereby improving the slag-forming speed of the semi-iron molten steelmaking process obtained by vanadium extraction smelting, as well as the slag quality and molten steel quality.

[0032] In some embodiments of the present invention, Figure 1 The step S10 shown, in the early stage of the oxygen blowing stage of the converter smelting, spraying a powdered slag-forming agent onto the surface of the semi-iron water obtained through vanadium extraction smelting, can include: spraying a powdered slag-forming agent onto the surface of the semi-iron water by top blowing during the 1min to 3min of the oxygen blowing stage.

[0033] In the first 1min~3min of the oxygen blowing stage, powdered slag-forming agent is sprayed onto the surface of semi-iron water by top blowing, and combined with the top blowing oxygen process, it can promote rapid slag formation in the early stage of oxygen blowing smelting.

[0034] In some embodiments of the present invention, the addition amount of the powdered slag-forming agent is (5-10) kg / t.

[0035] That is, in the first 1 to 3 minutes of the oxygen blowing stage, (5 to 10) kg of powdered slag-forming agent can be added to every 1 t of semi-iron water. For example, 5.5 kg, 6 kg, 6.5 kg, 7 kg or 7.5 kg of powdered slag-forming agent can be added to 1 t of semi-iron water. This allows the powdered slag-forming agent to fully react with the semi-iron water and maximize the slag formation speed.

[0036] In some embodiments of the present invention, Figure 1 The step S11 shown, in the middle and late stages of the oxygen blowing stage of the converter smelting, adding block slag-forming agent to the semi-iron water in batches, can include: obtaining a certain amount of block slag-forming agent from the converter silo at 3min~8min of the oxygen blowing stage, and adding the obtained block slag-forming agent to the semi-iron water; obtaining a certain amount of block slag-forming agent from the converter silo at 11min~13min of the oxygen blowing stage, and adding the obtained block slag-forming agent to the semi-iron water.

[0037] By intermittently adding blocky slag-forming agent to the semi-iron water during the 3min to 13min period of oxygen blowing, the slag-forming agent and the semi-iron water can fully react to improve the slag quality and molten steel quality.

[0038] In some embodiments of the present invention, obtaining a certain amount of block slag-forming agent from the converter silo at 3-8 minutes of the oxygen blowing stage of converter smelting may include: adding (10-15) kg / t of block slag-forming agent at 3-8 minutes of the oxygen blowing stage of converter smelting. Obtaining a certain amount of block slag-forming agent from the converter silo at 11-13 minutes of the oxygen blowing stage may include: adding (2-5) kg / t of block slag-forming agent at 11-13 minutes of the oxygen blowing stage.

[0039] That is, during the 3~8 minutes of oxygen blowing stage, (10~15) kg of massive slag-forming agent can be added to every 1 t of semi-iron water. For example, 10.5 kg, 11 kg, 11.5 kg, 12 kg, 12.5 kg, 13 kg, 13.5 kg or 14 kg of massive slag-forming agent can be added to 1 t of semi-iron water. This allows the massive slag-forming agent to fully react with the semi-iron water, thereby improving the slag-forming efficiency and stability.

[0040] During the 11-13 minutes of the oxygen blowing stage, (2-5) kg of massive slag-forming agent can be added to every 1 t of semi-iron water. For example, 2.5 kg, 3 kg, 3.5 kg, 4 kg or 4.5 kg of massive slag-forming agent can be added to 1 t of semi-iron water. This allows the massive slag-forming agent to fully react with the semi-iron water, thereby improving the slag-forming efficiency and stability.

[0041] In some examples of the present invention, Figure 2 As shown, the semi-steelmaking slag making method may include steps S20 to S22.

[0042] S20. Within 1min~3min of blowing oxygen, spray powdered slag-forming agent into the semi-iron water through the top blowing nozzle.

[0043] Among them, the addition amount of powdered slag-forming agent can be 5kg / t~10kg / t steel.

[0044] S21. Add block slag-forming agent to the semi-iron water through the converter silo within 3min~8min of oxygen blowing.

[0045] Among them, the addition amount of the massive slag-forming agent can be 10kg / t~15kg / t.

[0046] During the oxygen blowing period of 8min to 11min, only oxygen blowing is performed without adding any slag-forming agent.

[0047] S22. Add massive slag-forming agent to the semi-iron water through the converter silo within 11min~13min of oxygen blowing.

[0048] Among them, the addition amount of the massive slag-forming agent can be 2kg / t~5kg / t.

[0049] In some embodiments of the present invention, the powdery slag-forming agent may include any one or more of lime powder, limestone powder, dolomite powder and light-burned dolomite powder. The blocky slag-forming agent may include any one or more of lime, limestone, dolomite and light-burned dolomite.

[0050] For example, the powdered slag-forming agent may include lime powder and limestone powder. For example, the powdered slag-forming agent may also include limestone powder and dolomite powder. For example, the powdered slag-forming agent may also include lime powder, light-burned dolomite powder and dolomite powder. For example, the powdered slag-forming agent may also include lime powder, limestone powder, light-burned dolomite powder and dolomite powder.

[0051] For example, the bulk slag-forming agent may include lime and limestone. For example, the bulk slag-forming agent may also include limestone and dolomite. For example, the bulk slag-forming agent may also include lime, limestone and dolomite. For example, the bulk slag-forming agent may also include lime, limestone and light-burned dolomite.

[0052] In some embodiments of the present invention, the particle size of the powdered slag-forming agent is in the range of 0.01 mm to 1 mm, and the powdered slag-forming agent with a particle size in the range of 0.2 mm to 1 mm accounts for more than 70% of the total powdered slag-forming agent.

[0053] In some embodiments of the present invention, the particle size of the blocky slag-forming agent is in the range of 20 mm to 50 mm.

[0054] In some embodiments of the present invention, Figure 1 The step S10 shown, in the early stage of the oxygen blowing stage, spraying a powdered slag-forming agent onto the surface of the semi-iron water obtained through vanadium extraction smelting, can include: spraying the powdered slag-forming agent onto the surface of the semi-iron water through a nozzle arranged in an oxygen lance, wherein the carrier gas of the powdered slag-forming agent is nitrogen or oxygen.

[0055] In some embodiments of the present invention, Figure 1 The step S10 shown, in the early stage of the oxygen blowing stage, spraying a powdered slag-forming agent onto the surface of the semi-iron water obtained through vanadium extraction smelting, can include: spraying the powdered slag-forming agent onto the surface of the semi-iron water through a nozzle arranged outside the oxygen lance, wherein the carrier gas of the powdered slag-forming agent is nitrogen.

[0056] Specifically, the spraying method of spraying the powdered slag-forming agent into the metal molten pool through the top-blowing nozzle may include oxygen lance spraying or non-oxygen lance spraying. The oxygen lance spraying method is to spray the powdered slag-forming agent into the metal molten pool through a nozzle arranged at the center of the oxygen lance. Among them, the carrier gas during the process of spraying the powdered slag-forming agent through the oxygen lance can be oxygen or nitrogen. The non-oxygen lance spraying method is to spray the powdered agent into the metal molten pool through a nozzle arranged outside the oxygen lance. Among them, the carrier gas during the process of spraying the powdered slag-forming agent through the nozzle outside the oxygen lance can be nitrogen.

[0057] In some examples, during the converter slag-making process, the oxygen lance and the nozzle position can be adjusted to allow oxygen and powdered powder-forming agent to fully react with semi-iron molten steel, thereby improving the slag quality and molten steel quality.

[0058] In some examples, the oxygen lance height H during the nozzle powder spraying process may be higher than the oxygen lance height h during the non-powder spraying process. For example, the difference between the oxygen lance height H during the nozzle powder spraying process and the oxygen lance height h during the non-powder spraying process is ΔH=Hh=200mm, but not limited thereto, and the specific position of the oxygen lance can be freely adjusted according to the actual scenario.

[0059] In some examples, the gun position adjustment time T is extended by ΔT compared to the powder spray gun position adjustment time t, ΔT=Tt=(0.5~1.5)min. Wherein, T is 5~6min.

[0060] The concept of the present invention is described below in conjunction with a number of specific semi-steel steelmaking converter slag-making processes. It should be understood that the embodiments described herein are only used to illustrate and explain the present invention and are not used to limit the present invention.

[0061] Example 1 A 200t converter uses semi-iron water-based steelmaking obtained by vanadium extraction and smelting. The amount of block slag-making agent added through conventional processes is: lime 25kg / t, dolomite 10kg / t, silicon-containing material 5kg / t, oxygen lance smelting gun position is 1.8m, process gun position is 2.2m, and terminal gun position is 1.5m.

[0062] The final slag composition obtained through the above example is: basicity R=3.2, T.Fe=18%, fCaO=5.6%, and the oxygen content in the molten steel is [O]=600ppm ([C]=0.04%).

[0063] Example 2 A 200t converter uses semi-iron water-based steelmaking obtained by vanadium extraction smelting. The nozzle for powder injection is set in the oxygen lance, and the powder injection carrier gas is oxygen. The consumption of slag materials in the powder injection smelting process is: 5kg / t of dolomite powder and 5kg / t of lime powder are injected into the oxygen for 2~3min; 10kg / t of lump lime is added during the oxygen blowing for 3~8min; 3kg / t of lump dolomite is added during the oxygen blowing for 11~12min. The powder injection lance is located at 1.9m, the process lance is located at 2.0m, and the terminal lance is located at 1.7m.

[0064] The final slag composition obtained through the above example is: basicity R=3.1, T.Fe=16%, fCaO=3.6%, and the oxygen content of molten steel is [O]=450ppm ([C]=0.04%) By comparing Example 1 with Example 2, it can be seen that the T.Fe and fCaO contents in the final slag obtained by the semi-steel steelmaking converter slag making scheme implemented in the present invention are reduced, the oxygen content in the molten steel is reduced, and the quality of the final slag and the molten steel are improved.

[0065] Example 3 A 200t converter uses semi-iron water-based steelmaking obtained by vanadium extraction smelting. The nozzle for powder injection is set in the oxygen lance, and the powder injection carrier gas is nitrogen. The consumption of slag-making materials in the powder injection smelting process is: 5kg / t of dolomite powder and 8kg / t of lime powder are injected during oxygen blowing for 2~3min; 10kg / t of lump lime is added during oxygen blowing for 3~8min; during the slag splashing process, 2kg / t of lump dolomite and 3kg / t of lump lime are added; the powder injection gun position is 1.8m, the process gun position is 2.0m, and the terminal gun position is 1.8m.

[0066] The final slag composition obtained through the above example is: basicity R=3.23, T.Fe=15.7%, fCaO=2.2%, and the oxygen content of molten steel is [O]=400ppm ([C]=0.04%).

[0067] By comparing Example 1 with Example 3, it can be seen that the T.Fe and fCaO contents in the final slag obtained by the semi-steel steelmaking converter slag making scheme implemented in the present invention are reduced, the oxygen content in the molten steel is reduced, and the quality of the final slag and the molten steel are improved.

[0068] The embodiments of the present invention can improve the efficiency and stability of the semi-iron molten steelmaking process obtained by vanadium extraction smelting by adjusting the slag-forming agent addition method and process in the converter slag-forming process of semi-iron molten steelmaking and coordinating the oxygen blowing process, thereby improving the slag-forming speed, slag-forming quality and molten steel quality of the semi-iron molten steelmaking process obtained by vanadium extraction smelting, reducing the use of oxidants in subsequent steelmaking processes, and saving costs.

[0069] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0070] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A semi-steel steelmaking slag making method, characterized in that: include: In the early stage of oxygen blowing in converter smelting, a powdered slag-making agent is sprayed onto the surface of semi-iron molten steel obtained through vanadium extraction smelting; In the middle and late stages of oxygen blowing in converter smelting, a block slag-making agent is added to the semi-iron molten steel in batches to obtain slag.

2. The method according to claim 1, characterized in that In the early stage of oxygen blowing in converter smelting, powdered slag-making agent is sprayed onto the surface of semi-iron molten steel obtained through vanadium extraction smelting, including: During the oxygen blowing stage, 1 to 3 minutes later, a powdered slag-forming agent is sprayed onto the surface of the semi-iron water by top blowing.

3. The method according to claim 2, characterized in that The added amount of the powdered slag-forming agent is (5-10) kg / t.

4. The method according to claim 1, characterized in that: In the middle and late stages of oxygen blowing in converter smelting, a blocky slag-making agent is added to the semi-iron molten metal in batches, including: At 3-8 minutes of the oxygen blowing stage, a certain amount of block slag-making agent is obtained from the converter silo, and the obtained block slag-making agent is added to the semi-iron water; At 11 minutes to 13 minutes of the oxygen blowing stage, a certain amount of block slag-forming agent is obtained from the converter silo, and the obtained block slag-forming agent is added to the semi-iron water.

5. The method according to claim 1, characterized in that At 3min to 8min of the oxygen blowing stage, a certain amount of block slag-forming agent is obtained from the converter silo, including: at 3min to 8min of the oxygen blowing stage, the addition amount of the block slag-forming agent is (10-15) kg / t; At 11min~13min of the oxygen blowing stage, a certain amount of block slag-forming agent is obtained from the converter silo, including: at 11min~13min of the oxygen blowing stage, the addition amount of the block slag-forming agent is (2~5) kg / t.

6. The method according to claim 1, characterized in that The powdery slag-making agent includes any one or more of lime powder, limestone powder, dolomite powder and light-burned dolomite powder; The massive slag-forming agent includes any one or more of lime, limestone, dolomite and light-burned dolomite.

7. The method according to claim 6, characterized in that The particle size of the powdered slag-forming agent is in the range of 0.01 mm to 1 mm, and the powdered slag-forming agent with a particle size in the range of 0.2 mm to 1 mm accounts for more than 70% of the total powdered slag-forming agent.

8. The method according to claim 6, characterized in that The particle size of the block slag-forming agent is in the range of 20 mm to 50 mm.

9. The method according to claim 1, characterized in that: In the early stage of oxygen blowing in converter smelting, powdered slag-making agent is sprayed onto the surface of semi-iron molten steel obtained through vanadium extraction smelting, including: A powdery slag-forming agent is sprayed onto the surface of the semi-iron water through a nozzle arranged in the oxygen lance, wherein the carrier gas of the powdery slag-forming agent is nitrogen or oxygen.

10. The method according to claim 1, characterized in that In the early stage of oxygen blowing in converter smelting, powdered slag-making agent is sprayed onto the surface of semi-iron molten steel obtained through vanadium extraction smelting, including: A powdery slag-forming agent is sprayed onto the surface of the semi-iron water through a nozzle arranged outside the oxygen lance, wherein the carrier gas of the powdery slag-forming agent is nitrogen.

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