Converter vanadium extraction smelting process for low-vanadium molten iron

Abstract

The invention relates to the technical field of converter smelting, in particular to a low-vanadium molten iron converter vanadium extraction smelting process, low-vanadium molten iron is subjected to KR desulfurization and slagging-off, high or low-silicon pig iron is added into a converter according to the Si + Ti content of the molten iron for vanadium extraction smelting, a three-hole oxygen lance nozzle is used, the vanadium extraction oxygen supply strength is 1.8-2.8 / t.min, and a cooling material and a slag modifier are not added in the vanadium extraction smelting process; and the technical oxygen supply time is 4-6 minutes, the final temperature is 1350-1420 DEG C, the qualified vanadium slag is obtained, the technical problem that the grade of the vanadium slag smelted by extracting vanadium from the low-vanadium molten iron is low is solved, the content of the vanadium slag smelted by extracting vanadium from the low-vanadium molten iron can reach 13.85%, and effective recovery of the vanadium element in the low-vanadium molten iron is achieved.

Description

Technical Field

[0001] This invention relates to the field of converter smelting technology, and more specifically to a low-vanadium molten iron converter vanadium extraction smelting process. Background Technology

[0002] In recent years, the steel market has remained sluggish, putting immense pressure on enterprises. A certain steel plant, leveraging its proximity to the Panzhihua vanadium-titanium magnetite mining area, implemented a process in its blast furnace smelting to replace some ordinary ore and imported ore with vanadium-titanium magnetite, thus reducing iron costs. However, the vanadium-grade vanadium magnetite used had a low vanadium content, resulting in vanadium slag. Vanadium slag with a vanadium content >8% can be considered commercial vanadium slag. Blast furnace molten iron contains 0.12-0.25% vanadium. Vanadium slag is extracted using the converter vanadium extraction process common in the industry. With a vanadium content of 5-9%, the vanadium slag grade is low and does not meet the requirements for commercial vanadium slag, which increases the manufacturing cost of the steelmaking process. If the low-vanadium molten iron is directly used for steelmaking in the converter without removing vanadium, it will waste vanadium resources. Moreover, the high [V] and [Ti] content of low-vanadium molten iron makes direct steelmaking unfavorable for converter furnace maintenance.

[0003] In domestic converter vanadium extraction processes, the molten iron has a V content ≥ 0.25%. During the vanadium extraction process, iron-containing coolants are added for cooling, such as washed iron, iron pellets, fine-grained iron, ore pellets, and waste vanadium slag. The coolant TFe content is ≤ 65%, and the remaining 35% of impurities inevitably enter the vanadium slag, diluting its grade. When the molten iron Si+Ti content is < 0.35%, siliceous slag conditioners need to be added to adjust the slag state and improve vanadium yield. When the molten iron Si+Ti content is ≥ 0.35%, carbonaceous slag agglomerators need to be added to adjust the slag state, both increasing vanadium extraction costs and diluting the vanadium slag grade.

[0004] To address the aforementioned problems, our invention team proposes a low-vanadium molten iron converter vanadium extraction smelting process that eliminates the need for slag conditioners, thereby improving the vanadium slag extraction efficiency of low-vanadium molten iron vanadium extraction smelting. content. Summary of the Invention

[0005] In order to overcome the above-mentioned defects in the prior art, the purpose of this invention is to provide a low-vanadium molten iron converter vanadium extraction smelting process.

[0006] A vanadium extraction process for low-vanadium molten iron in a converter includes the following steps: S10, Low-vanadium molten iron KR desulfurization and slag removal, wherein the vanadium content of the low-vanadium molten iron is 0.12~0.25%, and slag removal is controlled according to a mirror surface ≥80%. If the molten iron S≤0.030%, only slag removal is performed without desulfurization. If the molten iron S>0.030%, desulfurization is performed. S20, low-vanadium molten iron is smelted by adding pig iron to extract vanadium. Molten iron is added first, followed by pig iron. To avoid the pig iron from piling up and affecting melting, the converter is rocked backward to 330° before returning to zero for vanadium extraction and oxygen supply smelting. The purpose of rocking the converter backward is to prevent the pig iron from piling up and affecting rapid melting. S30, Vanadium slag is produced. Vanadium slag is produced once every 2 to 5 heats. Half of the molten steel must be completely removed in each heat when vanadium slag is produced.

[0007] Further, in step S10, the desulfurization and slag removal of low-vanadium molten iron (KR), specifically, if the molten iron volume is 85-90t and the sulfur content (S) is >0.030%, desulfurization is performed. Slag removal is controlled to achieve a mirror finish ≥80%. The desulfurization aims for S <0.020%, and desulfurizing agent is added at a rate of 0.10 kg / t of iron per 0.001% S. The main component of the desulfurizing agent is CaO: 86%. 10%.

[0008] Preferably, step S10, low-vanadium molten iron KR desulfurization and slag removal, specifically involves: molten iron volume of 85-90t; if molten iron S > 0.030%, desulfurization is performed; slag removal is controlled to achieve a mirror finish ≥ 90%; the desulfurization target is S 0.020%, and desulfurizing agent is added based on a consumption of 0.15 kg / t of iron per 0.001% S. KR slag removal removes the iron slag before vanadium extraction from the molten iron; this portion of iron slag contains... ≤2%, carried into the converter to dilute vanadium slag The grade is approximately 1.0%.

[0009] Further, in step S20, the vanadium extraction smelting of low-vanadium molten iron with pig iron, the molten iron is added first, followed by pig iron. The converter is then rocked back to 330°C before returning to zero for vanadium extraction and oxygen supply smelting. If the Si+Ti content of the molten iron is less than 0.35%, then 7-12 tons of pig iron with Si ≥ 0.30% is added. The vanadium extraction furnace uses a three-hole oxygen lance with a high-low-low lance position, and the oxygen supply intensity for vanadium extraction is 1.8-2.8. / t.min, the oxygen supply gun positions are 1.6m for smelting 0-2 minutes, 1.3m for smelting 2-3.5 minutes, and 1.0m for 3.5 minutes to the end point.

[0010] Preferably, in step S20, the vanadium extraction smelting of low-vanadium molten iron with pig iron is specifically carried out by adding 9t of high-silicon pig iron with Si ≥ 0.30% if the Si + Ti content of the molten iron is less than 0.35%.

[0011] Further, step S20, the vanadium extraction smelting of low-vanadium molten iron with pig iron, specifically involves first adding molten iron, then adding pig iron, and then rotating the converter to 330°C before returning it to zero for vanadium extraction and oxygen supply smelting. If the Si+Ti content of the molten iron is 0.35-0.60%, then 10-15 tons of pig iron with Si < 0.30% is added. The vanadium extraction furnace uses a three-hole nozzle oxygen lance, with a high-low-low lance position, and the oxygen supply intensity for vanadium extraction is 1.8-2.8. / t.min, the oxygen supply gun positions are 1.6m for smelting 0-2 minutes, 1.2m for smelting 2-3.5 minutes, and 0.9m for 3.5 minutes to the end point.

[0012] Preferably, in step S20, the vanadium extraction smelting of low-vanadium molten iron by adding pig iron specifically involves adding 11t of pig iron with Si < 0.30% if the Si + Ti content of the molten iron is 0.35-0.60%.

[0013] Furthermore, in step S20, the vanadium extraction smelting of low-vanadium molten iron with pig iron, specifically involves the following: no cooling material or slag conditioner is added during the vanadium extraction smelting process; the oxygen supply time is 4-6 minutes; and the endpoint of vanadium extraction is observed when the flame at the converter mouth changes from dark red to bright. The endpoint control parameters are: target temperature 1350-1420℃, endpoint C: 3.0~3.8%, V: 0.006-0.035%, vanadium oxidation rate ≥80%, and average vanadium oxidation rate 87%.

[0014] Furthermore, in step S30, vanadium slag is discharged. Specifically, the amount of pig iron added is adjusted to 7-12t for each vanadium slag discharge furnace, and the final temperature is controlled at a target of 1365-1420℃ to ensure complete melting of pig iron, a relatively thick vanadium slag, and complete discharge of vanadium slag.

[0015] Preferably, step S30, which involves discharging vanadium slag, specifically involves adjusting the amount of pig iron added in each vanadium slag discharge furnace to 7-12t, controlling the final temperature to a target of 1380℃, ensuring complete melting of the pig iron, a relatively thick vanadium slag consistency, and thorough discharge of the vanadium slag.

[0016] The beneficial effects of this invention are: 1. The entire cooling process utilizes pig iron, which contains ≥94% Fe, resulting in fewer non-metallic inclusions. Pig iron has a low melting temperature, beginning to melt at temperatures above 1200℃. Furthermore, the solid-state and hot-state heat capacities of pig iron are almost identical to those of steel. By carefully controlling the carbon-vanadium transformation reaction time in the molten pool, the carbon oxidation reaction rate is reduced. This cooling effect is superior to that of iron oxide balls, vanadium slag, and scrap steel. On average, the cooling effect of vanadium slag is significantly lower. Grade content ≥11%.

[0017] 2. The slag content of molten iron is 0.5%, which is added to the vanadium extraction furnace to reduce vanadium slag. With a content of approximately 1.0%, the low-grade iron slag in the iron ladle is removed using a KR desulfurization station, improving the vanadium extraction efficiency. content.

[0018] 3. Calculate the heat balance of various cooling materials and the dilution of vanadium slag grade by impurities. The optimal pig iron content (Fe ≥ 94%) and remaining elemental components (< 6%) minimizes the harm to vanadium slag grade dilution. The low melting point of pig iron (1168℃) facilitates rapid melting and cooling. Furthermore, based on the Si+Ti content of low-vanadium molten iron, a combination of high and low Si pig iron is used for vanadium extraction, eliminating the need for slag conditioners, resulting in good vanadium slag condition at the end. This demonstrates that adding all pig iron after mixing balances the heat, and adding pig iron with different Si contents based on the Si+Ti content of the molten iron, avoids the introduction of impurities by coolants and slag conditioners, thus diluting the vanadium slag grade. This process achieves vanadium slag extraction from low-vanadium molten iron. The content can reach 13.85%, achieving good economic benefits. Detailed Implementation

[0019] The present invention will now be described in detail with reference to specific embodiments. The illustrative embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention.

[0020] Example 1 S10, initial molten iron C: 4.19%, S: 0.064%, V: 0.156%, Si+Ti: 0.18%. KR desulfurizes at a rate of 0.044% S using 6.6 kg / t of desulfurizing agent. After desulfurization, the slag surface is mirror-like (≥90%) after 6 minutes of slag removal. The S content at the outlet is 0.020%. KR removes the slag before vanadium extraction from the molten iron. This portion of the slag contains... ≤2%, carried into the converter to dilute vanadium slag The grade is approximately 1.0%.

[0021] In the S20 vanadium extraction furnace, 88t of molten iron is first added, followed by 8.1t of high-silicon pig iron. The furnace is then rotated backwards to 330°C before returning to zero for vanadium extraction and oxygen supply smelting. The vanadium extraction furnace uses a three-hole oxygen lance with a high-low-low lance position. The oxygen supply intensity for vanadium extraction is 2.3. / t.min, the oxygen supply lance position is 1.6m for smelting from 0-2 minutes, 1.3m for smelting from 2-3.5 minutes, and 1.0m from 3.5 minutes to the endpoint. No cooling material or slag conditioner was added during the vanadium extraction process. The process oxygen supply time is 5.1 minutes. The endpoint of vanadium extraction is defined as when the flame at the converter mouth changes from dark red to bright. The endpoint temperature is 1375℃, and the endpoint C: 3.56%, V: 0.018%, and vanadium oxidation rate is 88.5%.

[0022] S30. After four consecutive furnaces of vanadium slag are produced, the molten steel must be completely discharged during each furnace slag production. The amount of pig iron added during the vanadium slag production furnace is adjusted to 7t, and the final temperature is 1378℃. When the molten steel is discharged, the pig iron is observed to be completely melted and the vanadium slag is relatively thick. The vanadium slag must be completely discharged during the vanadium slag production.

[0023] Example 2 S10, initial molten iron C: 4.41%, S: 0.029%, V: 0.205%, Si+Ti: 0.40%, KR without desulfurization, only slag removal, slag surface mirror finish ≥90% after 3 minutes of slag removal.

[0024] In the S20 vanadium extraction furnace, 87.3t of molten iron is first added, followed by 12.3t of low-silicon pig iron. The pig iron converter is then tilted backward to 330°C before returning to zero for vanadium extraction and oxygen supply smelting. The vanadium extraction furnace uses a three-hole oxygen lance with a high-low-low lance position. The oxygen supply intensity for vanadium extraction is 2.13. The oxygen supply lance position was 1.6m for the first 0-2 minutes of smelting, 1.2m for the next 2-3.5 minutes, and 0.9m from the 3.5-minute mark to the final position. No cooling material or slag conditioner was added during the vanadium extraction process. The process oxygen supply time was 4.42 minutes. The endpoint of vanadium extraction was defined as the change from dark red to bright red flame at the converter mouth, with a final temperature of 1365℃. The endpoint C content was 3.95%, V content was 0.028%, and the vanadium oxidation rate was 86.3%.

[0025] S30. Vanadium slag is produced once every 4 heats of continuous smelting. Half of the molten steel must be completely discharged in the vanadium slag discharge heat. The amount of pig iron added in the vanadium slag discharge heat is adjusted to 12t, and the final temperature is 1380℃ to ensure that the pig iron is completely melted. The vanadium slag is relatively thick and must be completely discharged when discharging the vanadium slag.

[0026] Example 3 S10, initial C in molten iron: 3.98%, S: 0.074%, V: 0.189%, Si+Ti: 0.26%, KR desulfurizes iron by consuming 8.1 kg / t of desulfurizing agent according to the desulfurization S 0.054%, after desulfurization, the slag surface is mirror-like ≥90% after 7 minutes of slag skimming, and the S at the station is 0.016%.

[0027] In the S20 vanadium extraction furnace, 87t of molten iron is first added, followed by 8.5t of high-silicon pig iron. The furnace is then rotated backwards to 330°C before returning to zero for vanadium extraction and oxygen supply smelting. The vanadium extraction furnace uses a three-hole oxygen lance with a high-low-low lance position. The oxygen supply intensity for vanadium extraction is 2.6. / t.min, the oxygen supply lance position is 1.6m for smelting from 0-2 minutes, 1.3m for smelting from 2-3.5 minutes, and 1.0m from 3.1 minutes to the endpoint. No cooling material or slag conditioner was added during the vanadium extraction process. The process oxygen supply time is 4 minutes. The endpoint of vanadium extraction is defined as when the flame at the converter mouth changes from dark red to bright. The endpoint temperature is 1381℃, and the endpoint C: 3.59%, V: 0.027%, and vanadium oxidation rate is 85.7%.

[0028] S30. Vanadium slag is produced once every 5 heats of continuous smelting. The molten steel must be completely discharged in the vanadium slag discharge heat. The amount of pig iron added is adjusted to 7.8t in the vanadium slag discharge heat. The final temperature is 1365℃. When the molten steel is discharged, the pig iron is observed to be completely melted and the vanadium slag is in good condition. The vanadium slag is discharged completely.

[0029] Example 4 S10, initial molten iron C: 3.8%, S: 0.025%, V: 0.20%, Si+Ti: 0.25%, KR without desulfurization, only slag removal, slag surface mirror finish ≥90% after 3 minutes of slag removal.

[0030] In the S20 vanadium extraction furnace, 87.5 tons of molten iron are first added, followed by 9 tons of high-silicon pig iron. The pig iron converter is then tilted backwards to 330°C before returning to zero for vanadium extraction and oxygen supply smelting. The vanadium extraction furnace uses a three-hole oxygen lance with a high-low-low lance position. The oxygen supply intensity for vanadium extraction is 2.16. / t.min, the oxygen supply lance position is 1.6m for smelting from 0-2 minutes, 1.3m for smelting from 2-3.5 minutes, and 1.0m from 3.5 minutes to the endpoint. No cooling material or slag conditioner was added during the vanadium extraction process. The process oxygen supply time is 5.5 minutes. The endpoint of vanadium extraction is defined as when the flame at the converter mouth changes from dark red to bright. The endpoint temperature is 1361℃, and the endpoint C: 3.46%, V: 0.025%, and vanadium oxidation rate is 87.5%.

[0031] S30. Vanadium slag is produced once every 5 heats of continuous smelting. The semi-finished steel must be completely discharged in the vanadium slag discharge heat. The amount of pig iron added is adjusted to 7.1t in the vanadium slag discharge heat. The final temperature is 1393℃. When the semi-finished steel is discharged, the pig iron is observed to be completely melted and the vanadium slag is in good condition. The vanadium slag is discharged completely.

[0032] Example 5 S10, initial C in molten iron: 4.03%, S: 0.044%, V: 0.23%, Si+Ti: 0.43%, KR consumes 3.6 kg / t iron for desulfurization according to the desulfurization S 0.024%, after desulfurization, the slag surface is mirror surface ≥90% after 6 minutes of slag removal, and the S at the station is 0.016%.

[0033] S20: 87t of molten iron is first added to the vanadium extraction furnace, followed by 11t of low-silicon pig iron. The pig iron converter is then tilted backward to 330°C before returning to zero for vanadium extraction and oxygen supply smelting. The vanadium extraction furnace uses a three-hole oxygen lance with a high-low-low lance position. The oxygen supply intensity for vanadium extraction is 2.1. / t.min, the oxygen supply lance position is 1.6m for smelting from 0-2 minutes, 1.2m for smelting from 2-3.5 minutes, and 0.9m from 3.5 minutes to the endpoint. No cooling material or slag conditioner was added during the vanadium extraction process. The process oxygen supply time is 4.2 minutes. The endpoint of vanadium extraction is defined as when the flame at the converter mouth changes from dark red to bright. The endpoint temperature is 1400℃, and the endpoint C: 3.73%, V: 0.032%, and vanadium oxidation rate is 86%.

[0034] S30. After three consecutive furnaces of vanadium slag are produced, the molten steel must be completely discharged during each furnace slag discharge. The amount of pig iron added during the vanadium slag discharge is adjusted to 9.7t, and the final temperature is 1379℃. When the molten steel is discharged, the pig iron is observed to be completely melted and the vanadium slag is in good condition. The vanadium slag must be completely discharged during the vanadium slag discharge.

[0035] Example 6 S10, initial molten iron C: 4.41%, S: 0.028%, V: 0.256%, Si+Ti: 0.47%, KR without desulfurization, only slag removal, slag surface mirror finish ≥90% after 3 minutes of slag removal.

[0036] In the S20 vanadium extraction furnace, 84.7 tons of molten iron are first added, followed by 14 tons of low-silicon pig iron. The pig iron converter is then tilted backwards to 330°C before returning to zero for vanadium extraction and oxygen supply smelting. The vanadium extraction furnace uses a three-hole oxygen lance with a high-low-low lance position. The oxygen supply intensity for vanadium extraction is 1.95. The oxygen supply lance position was 1.6m for 0-2 minutes of smelting, 1.2m for 2 minutes of smelting, and 0.85m from 3.5 minutes to the endpoint. No cooling material or slag conditioner was added during the vanadium extraction process. The process oxygen supply time was 5.2 minutes. The endpoint of vanadium extraction was defined as when the flame at the converter mouth changed from dark red to bright red. The endpoint temperature was 1406℃, and the endpoint C: 4.06%, V: 0.035%, and vanadium oxidation rate was 86.3%.

[0037] S30. Continuous smelting: vanadium slag is produced once every two furnaces. The molten steel must be completely discharged during the vanadium slag discharge furnace. The amount of pig iron added is adjusted to 11t during the vanadium slag discharge furnace. The final temperature is 1406℃. When the molten steel is discharged, the pig iron is observed to be completely melted and the vanadium slag is in good condition. The vanadium slag must be completely discharged during the vanadium slag discharge.

[0038] To verify the effectiveness of this invention, the inventors conducted verification experiments, excerpts of which are as follows: Comparative Example 1 S10, low vanadium molten iron KR desulfurization slag removal, molten iron initial C: 4.21%, S: 0.025%, V: 0.207%, Si+Ti: 0.29%, vanadium extraction directly without entering KR slag removal.

[0039] S20, low-vanadium iron vanadium extraction smelting: 88.2t of molten iron is first added to the vanadium extraction furnace, followed by 1.58t of cold charge and 5.8t of pig iron. The furnace is then directly switched to zero for vanadium extraction and oxygen supply. The vanadium extraction furnace uses a three-hole oxygen lance with a high-low-high-low lance position, and an oxygen supply intensity of 2.3. / t.min, the oxygen supply lance positions are 1.7m for smelting from 0-2 minutes, 1.3m for 2 minutes, 1.5m for 3 minutes, and 1.1m for 4 minutes to the end point. During the vanadium extraction smelting process, 1.58t of cooling material and 0.4t of slag conditioner are added. The main components of the slag conditioner are... 57.02% Vanadium content was 21.44%, oxygen supply time was 4.6 minutes, and the endpoint of vanadium extraction was observed when the flame at the converter mouth changed from dark red to bright. The endpoint temperature was 1365℃, and the endpoint C content was 3.76%, V content was 0.040%, and the vanadium oxidation rate was 81.2%.

[0040] S30, vanadium slag is produced. Vanadium slag is produced once in 3 furnaces. 5t of pig iron is added in the second vanadium slag furnace. The final temperature is 1372℃. When semi-steel is produced, a small amount of pig iron is not completely melted. The vanadium slag is dry. A small amount of semi-steel remains in the second vanadium slag furnace due to the dry slag coating the steel.

[0041] Comparative Example 2 S10, initial molten iron C: 4.33%, S: 0.044%, V: 0.223%, Si+Ti: 0.45%, vanadium was extracted directly without KR slag removal.

[0042] S20: 89t of molten iron is first added to the vanadium extraction furnace, followed by 6t of pig iron. The process immediately returns to zero for oxygen supply during vanadium extraction. The furnace uses a three-hole oxygen lance with a high-low-high-low lance position. The oxygen supply intensity for vanadium extraction is 2.1. / t.min, the oxygen supply lance positions are 1.6m for smelting from 0-2 minutes, 1.2m for 2 minutes, 1.4m for 3 minutes, and 1.0m for the final stage from 4 minutes. 2.8t of cooling material is added during the vanadium extraction process. The process oxygen supply time is 4.5 minutes. The endpoint of vanadium extraction is defined as the change from dark red to bright red flame at the converter mouth, with an endpoint temperature of 1390℃. The endpoint C: 3.80%, V: 0.045%, and vanadium oxidation rate of 79.8%.

[0043] S30. Continuous smelting: vanadium slag is produced once every two furnaces. The molten steel must be completely removed during the vanadium slag producing furnace. The amount of pig iron added is adjusted to 7t during the vanadium slag producing furnace. The final temperature is 1381℃. When the molten steel is produced, the pig iron is observed to be completely melted. The vanadium slag is thin and corrodes the furnace lining. The loss of vanadium slag is serious when the vanadium slag is produced.

[0044] Table 1 shows a comparison of the process effects of Comparative Examples 1-2 with Examples 1-6 of this application; As shown in Table 1, this application does not include cold feed or slag conditioner, significantly simplifying the production process and reducing operational complexity and raw material costs. It also significantly improves the grade of vanadium slag. With a maximum yield of up to 13.85%, it solves the problem of high grade and low cost in vanadium slag extraction from low-vanadium molten iron, achieves effective recovery of vanadium elements from low-vanadium molten iron, and effectively controls the metallic iron content of vanadium slag without adding slag conditioners, thereby improving separation efficiency.

[0045] Although the present invention has been described in detail above with general descriptions, specific embodiments, and experimental comparisons, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A vanadium extraction process for low-vanadium molten iron in a converter, characterized in that, Includes the following steps: S10, Low-vanadium molten iron KR desulfurization and slag removal, wherein the vanadium content of the low-vanadium molten iron is 0.12~0.25%, and slag removal is controlled according to a mirror surface ≥80%. If the molten iron S≤0.030%, only slag removal is performed without desulfurization. If the molten iron S>0.030%, desulfurization is performed. S20, low vanadium molten iron is added to pig iron for vanadium extraction smelting. First, molten iron is added, then pig iron is added. The pig iron converter is then rocked back to 330° and then returned to zero for vanadium extraction and oxygen supply smelting. S30, Vanadium slag is produced. Vanadium slag is produced once every 2 to 5 heats. Half of the molten steel must be completely removed in each heat when vanadium slag is produced.

2. The low-vanadium iron converter vanadium extraction smelting process according to claim 1, characterized in that, The step S10, low-vanadium molten iron KR desulfurization and slag removal, specifically involves molten iron with a quantity of 85-90t. If the molten iron S>0.030%, KR stirring desulfurization is performed, and slag removal is controlled to achieve a mirror finish of ≥80%. The desulfurization aims for S<0.020%, and desulfurizing agent is added based on a consumption of 0.10-0.25kg / t of iron per 0.001% S.

3. The low-vanadium iron converter vanadium extraction smelting process according to claim 2, characterized in that, The step S10, low-vanadium molten iron KR desulfurization and slag removal, specifically involves molten iron with a quantity of 85-90t. If the sulfur content (S) in the molten iron is greater than 0.030%, KR stirring desulfurization is performed. Slag removal is controlled to achieve a mirror finish of ≥90%. The desulfurization aims for an S content of 0.020%, and desulfurizing agent is added based on a consumption of 0.15 kg / t of iron per 0.001% S content.

4. The low-vanadium iron converter vanadium extraction smelting process according to claim 1, characterized in that, The step S20, low-vanadium molten iron vanadium extraction smelting with pig iron, specifically involves first adding molten iron, then adding pig iron. The converter is then rocked back to 330°C before returning to zero for vanadium extraction and oxygen supply smelting. If the molten iron Si+Ti < 0.35%, then 7-12 tons of pig iron with Si ≥ 0.30% is added. The vanadium extraction furnace uses a three-hole nozzle oxygen lance, with a high-low-low lance position, and the oxygen supply intensity for vanadium extraction is 1.8-2.

8. / t.min, the oxygen supply gun positions are 1.6m for smelting 0-2 minutes, 1.3m for smelting 2-3.5 minutes, and 1.0m for smelting 3.5 minutes to the end point.

5. The low-vanadium iron converter vanadium extraction smelting process according to claim 4, characterized in that, The step S20, vanadium extraction smelting of low-vanadium molten iron by adding pig iron, specifically involves adding 9t of pig iron with Si ≥ 0.30% if Si + Ti < 0.35% in the molten iron.

6. The low-vanadium iron converter vanadium extraction smelting process according to claim 1, characterized in that, The step S20, low-vanadium molten iron vanadium extraction smelting with pig iron, specifically involves first adding molten iron, then adding pig iron. The converter is then rocked back to 330°C before returning to zero for vanadium extraction and oxygen supply smelting. If the Si+Ti content of the molten iron is 0.35-0.60%, then 10-15 tons of pig iron with Si < 0.30% is added. The vanadium extraction furnace uses a three-hole oxygen lance with a high-low-low lance position, and the oxygen supply intensity for vanadium extraction is 1.8-2.

8. / t.min, the oxygen supply gun positions are 1.6m for smelting 0-2 minutes, 1.2m for smelting 2-3.5 minutes, and 0.9m for 3.5 minutes to the end point.

7. The low-vanadium iron converter vanadium extraction smelting process according to claim 6, characterized in that, The step S20, vanadium extraction smelting of low-vanadium molten iron by adding pig iron, specifically involves adding 11t of pig iron with Si < 0.30% if the Si + Ti content of the molten iron is 0.35-0.60%.

8. The low-vanadium iron converter vanadium extraction smelting process according to claim 1, characterized in that, The step S20, vanadium extraction smelting of low-vanadium molten iron with pig iron, specifically involves supplying oxygen for 4-6 minutes and observing the converter furnace flame change from dark red to bright red as the endpoint of vanadium extraction. The target temperature for the endpoint is controlled at 1350-1420℃, with endpoint C: 3.0~3.8%, V: 0.006-0.035%, vanadium oxidation rate ≥80%, and average vanadium oxidation rate 87%.

9. The low-vanadium iron converter vanadium extraction smelting process according to claim 1, characterized in that, The step S30, vanadium slag removal, specifically involves adjusting the amount of pig iron added to 7-12t for each vanadium slag removal furnace, controlling the final temperature to a target of 1365-1420℃, ensuring complete melting of the pig iron, a relatively thick vanadium slag consistency, and complete removal of the vanadium slag during the removal process.

10. The low-vanadium iron converter vanadium extraction smelting process according to claim 1, characterized in that, The step S30, vanadium slag removal, specifically involves adjusting the amount of pig iron added to 9t for each vanadium slag removal furnace, controlling the final temperature to a target of 1380℃, ensuring complete melting of the pig iron, and producing a relatively thick vanadium slag that is completely removed during vanadium slag removal.

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