A method for strengthening vanadium extraction in a converter

Abstract

The present application relates to the technical field of metallurgy, in particular to a method for strengthening converter vanadium extraction, molten iron containing vanadium is mixed into the converter for vanadium extraction, and gas is supplied at the bottom of the converter after shaking, the bottom blowing element of the bottom gas supply adopts a single ring slit combined with a central cluster tube mode, the single ring slit is sleeved outside the central cluster tube, the central cluster tube passes CO2 and CH4, the single ring slit passes CO2, and the single ring slit adopts pulse control.

Description

Technical Field

[0001] This invention relates to the field of metallurgical technology, specifically to a method for enhancing vanadium extraction in a converter. Background Technology

[0002] Vanadium is an important transition metal element, primarily derived from vanadium-titanium magnetite. Converter vanadium extraction is one of the main industrial routes for indirect vanadium extraction from vanadium-titanium magnetite, and it is widely used in China (e.g., by Panzhihua Iron and Steel Group and Chengde Iron and Steel Group). The principle involves using oxygen blowing in a converter to oxidize vanadium-containing molten iron, achieving selective oxidation of vanadium into the slag phase to form vanadium slag. During the converter blowing process, temperature control and kinetic improvement are crucial for reducing residual vanadium.

[0003] Patent CN201910093569.X provides a method for vanadium extraction using a binary gas-supply converter. Based on the silicon content and temperature of the vanadium-containing molten iron, the gas supply and blowing conditions are determined. Specifically, when the Si content of the vanadium-titanium molten iron is less than 0.15 wt% and the temperature is 1280–1300 °C, after the vanadium-containing molten iron enters the converter, it is blown with gas through an oxygen lance. O2 is blown in during the period from the start of blowing to 60–120 seconds before the end of blowing. During the period from 60 to 120 seconds before the end of the blowing process to the end of the blowing process, a mixture of O2 and N2 gas is blown in, with the N2 consumption ratio being 20% ​​to 40%; the vanadium extraction coolant is added within 2 minutes after the start of the blowing process. When the Si content of vanadium-titanium molten iron is ≥0.15wt% and the temperature is 1280~1300℃, after the vanadium-containing molten iron enters the converter, it is blown by oxygen lance to blow gas. O2 is blown from the start of blowing to 60~120s after the start of blowing. During the period from 60 to 120 seconds after the start of blowing to 60 to 120 seconds before the end of blowing, a mixture of O2 and N2 gas is blown and sprayed, with the N2 consumption ratio being 10% to 30%; during the period from 60 to 120 seconds before the end of blowing to the end of blowing, a mixture of O2 and N2 gas is blown and sprayed, with the N2 consumption ratio being 20% ​​to 40%. The vanadium-containing coolant is added within 2 minutes after the start of the blowing process. When the temperature of the vanadium-titanium molten iron is >1300℃, after the vanadium-containing molten iron enters the converter, it is blown by gas through an oxygen lance. During the period from the start of the blowing process to 60 to 120 seconds before the end of the blowing process, a mixture of O2 and N2 gas is blown, with the N2 consumption ratio being 20% ​​to 30%. From 60-120 seconds before the end of blowing to the end of blowing, a mixture of O2 and N2 gas is blown in, with N2 consumption at 30%-40%; the vanadium extraction coolant is added within 2 minutes of the start of blowing. This solves the problem of high residual vanadium and low V2O5 in vanadium slag under different temperatures and silicon contents of molten iron. Although top blowing of binary gas slows down the temperature rise of the molten pool, the temperature control and stirring effect of bottom blowing N2 is not as good as that of CO2, and there is still room for further reduction in residual vanadium.

[0004] Patent CN202011380715.6 describes a method for asymmetric bottom-blowing CO2 vanadium extraction in a converter. The method involves adding vanadium-containing molten iron to the converter, shaking the furnace, and then starting CO2 blowing from the bottom of the converter while simultaneously using an oxygen lance for top-blowing O2. The oxygen supply intensity of the oxygen lance is 1.5–3.0 Nm. 3 / min·t iron, lance position controlled at 1.7~2.0m, add coolant within 2 minutes of oxygen lance starting to blow, and blow to the end point; The bottom of the converter is laid with permeable bricks in three zones: Zone I, Zone II, and Zone III. The permeable bricks in Zones I and III are symmetrically distributed, while those in Zone II are asymmetrically distributed, with an included angle of 80°–100°. The bottom-blown CO2 flow rate of a single permeable brick in Zone I is controlled at 100–120 Nm³. 3 / min, the bottom-blown CO2 flow rate of a single permeable brick in Zone II is 130-150 Nm³. 3 The CO2 flow rate from the bottom blown onto a single permeable brick in Zone III is 160–180 Nm³ / min. 3 / min. Carbon dioxide recovery for vanadium extraction in the converter was achieved, suppressing molten pool temperature rise and effectively reducing residual vanadium content. Despite improved molten pool kinetics, the presence of top-blown O2 leading to excessively high oxidation temperatures means there is still room for further reduction in residual vanadium. Summary of the Invention

[0005] The purpose of this invention is to provide a method for enhancing vanadium extraction in a converter, thereby solving the technical problem that existing technologies cannot further reduce residual vanadium.

[0006] This invention discloses a method for enhancing vanadium extraction in a converter. Vanadium-containing molten iron is added to the vanadium extraction converter, and gas is supplied to the bottom of the converter after shaking. The bottom blowing element for the bottom gas supply adopts a combination mode of a single annular slit and a central cluster tube. The single annular slit is sleeved outside the central cluster tube. The central cluster tube is circulated with CO2 and CH4, and the single annular slit is circulated with CO2. The single annular slit is controlled by pulse.

[0007] Furthermore, the space between the central bundle tubes is filled with magnesium-carbon refractory material, and both the central bundle tubes and the single circumferential seam are stainless steel tubes.

[0008] Furthermore, the central bundle tube has a diameter of 2-3 mm and a wall thickness of 1-2 mm.

[0009] Furthermore, the pressure of the central bundle tube is 0.7~1MPa.

[0010] Furthermore, the volume fraction of CH4 in the central bundle tube is 25-40%, and the flow rate of the central bundle tube is 130-150 Nm³. 3 / min.

[0011] Furthermore, the single-ring seam pressure is 0.7~1MPa, and the single-ring seam width is 1~2.5mm.

[0012] Furthermore, the pulse control specifically refers to a flow rate of 60~80 Nm. 3 / min air supply for 20s, then 100~120Nm 3 Supply air at 20 seconds per minute, and repeat this cycle until the blowing process is complete.

[0013] Furthermore, the pulse control specifically refers to a flow rate of 60 Nm³. 3 / min air supply for 20s, then 120Nm 3 Supply air at 20 seconds per minute, and repeat this cycle until the blowing process is complete.

[0014] Furthermore, it also includes top blowing, which supplies CO2 and O2 at a supply intensity of 2.0–3.0 Nm³. 3 / min·t iron.

[0015] Furthermore, when the molten iron temperature is greater than 1300℃, the volume fraction of top-blown CO2 is controlled at 40~50%; when the molten iron temperature is less than 1250℃, the volume fraction of top-blown CO2 is controlled at 15~25%; and when the temperature is between the two, the volume fraction of top-blown CO2 is controlled at 25~40%.

[0016] Furthermore, the position of the top-blown oxygen lance is controlled at 1.7-2.0m, and 15-22 kg / t of coolant is added within 2 minutes of the oxygen lance starting to blow, until the final temperature is below 1390℃.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. Top-blowing O2-CO2 oxygen supply reduces the oxidation heating rate, creating favorable thermodynamic conditions for vanadium oxidation. Pulsed bottom-blowing reduces the dead zone volume of the molten pool, enhances molten pool stirring, and significantly improves vanadium extraction kinetics.

[0018] 2. This invention makes full use of bottom blowing elements and gas supply methods, enhances molten pool dynamics and temperature control, and compared with traditional combined blowing converter for vanadium extraction, the vanadium oxidation rate is increased by more than 1.3%, and the economic benefit generated per ton of vanadium-containing molten iron is greater than 1.3 yuan. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the bottom blowing element structure of the present invention.

[0021] In the above figures, the meanings of each mark are as follows: 1-single circumferential seam, 2-central cluster, 3-stainless steel pipe, 4-magnesium carbon refractory material. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0023] The bottom blowing element used in the following embodiments is as follows: Figure 1 As shown, a combination of a single annular seam 1 and a central bundled tube 2 is adopted. The single annular seam 1 is sleeved outside the central bundled tube 2, and the space between the central bundled tubes is filled with magnesia-carbon refractory material 4. Both the central bundled tube and the single annular seam are stainless steel tubes 3. Example 1 This embodiment discloses a method for enhancing vanadium extraction in a converter, including the following steps: The vanadium-containing molten iron is added to the vanadium extraction converter, and gas is supplied to the bottom of the converter after the furnace is shaken.

[0024] The bottom-blowing element adopts a combination of a single annular slit and a central bundled tube. The central bundled tube has a diameter of 2mm, a wall thickness of 1mm, a pressure of 0.7MPa, and is supplied with a CO2 + CH4 mixture, with a CH4 volume fraction of 25% and a flow rate of 130Nm³. 3 / min.

[0025] The single circumferential slit width is 1mm, the CO2 pressure is 0.7MPa, and the flow rate is 60Nm³. 3 / min air supply for 20s, then 100Nm 3 Supply air at 20 seconds per minute, and repeat this cycle until the blowing process is complete.

[0026] The top-blown oxygen lance supplies CO2+O2, with a supply intensity of 2.0–3.0 Nm³. 3 / min·t iron.

[0027] The molten iron temperature is above 1300℃, and the CO2 volume fraction is controlled at 40%. The molten iron temperature is below 1250℃, and the CO2 volume fraction is controlled at 15%. When the temperature is between the two, the CO2 volume fraction is controlled at 25%.

[0028] The lance position is controlled at 1.7 to 2.0 meters. Within 2 minutes of starting the oxygen lance, add 15 kg / t of coolant to the iron and blow until the final temperature is below 1390℃.

[0029] By making full use of bottom-blowing elements and gas supply methods, the dynamics and temperature control of the molten pool are enhanced, and the vanadium oxidation rate is 89.5%. Compared with the traditional combined blowing converter for vanadium extraction, the vanadium oxidation rate is increased by 1.5%, and the economic benefit generated per ton of vanadium-containing molten iron is 1.5 yuan.

[0030] Example 2 The vanadium-containing molten iron is added to the vanadium extraction converter, and gas is supplied to the bottom of the converter after the furnace is shaken.

[0031] The bottom-blowing element adopts a combination of a single annular slit and a central cluster tube. The central cluster tube has a diameter of 2.5 mm, a wall thickness of 1.7 mm, a pressure of 0.85 MPa, and is supplied with a CO2 + CH4 mixture, with a CH4 volume fraction of 32% and a flow rate of 140 Nm³. 3 / min.

[0032] The single annular slit width is 1.7 mm, the CO2 pressure is 0.85 MPa, and the flow rate is 70 Nm³. 3 / min air supply for 20s, then 110Nm 3 Supply air at 20 seconds per minute, and repeat this cycle until the blowing process is complete.

[0033] The top-blown oxygen lance supplies CO2+O2, with a supply intensity of 2.0–3.0 Nm³. 3 / min·t iron.

[0034] The molten iron temperature is above 1300℃, and the CO2 volume fraction is controlled at 45%. The molten iron temperature is below 1250℃, and the CO2 volume fraction is controlled at 20%. When the temperature is between the two, the CO2 volume fraction is controlled at 32%.

[0035] The lance position is controlled at 1.7-2.0m. Within 2 minutes of the oxygen lance starting to blow, 18kg / t of coolant is added, and the blowing is carried out until the final temperature is below 1390℃.

[0036] By making full use of bottom-blowing elements and gas supply methods, the dynamics and temperature control of the molten pool are enhanced, and the vanadium oxidation rate is 89.8%. Compared with the traditional combined blowing converter for vanadium extraction, the vanadium oxidation rate is increased by 1.8%, and the economic benefit generated per ton of vanadium-containing molten iron is 1.8 yuan.

[0037] Example 3 The vanadium-containing molten iron is added to the vanadium extraction converter, and gas is supplied to the bottom of the converter after the furnace is shaken.

[0038] The bottom-blowing element adopts a combination of a single annular slit and a central bundled tube. The central bundled tube has a diameter of 3mm, a wall thickness of 2mm, a pressure of 1MPa, and is supplied with a CO2 + CH4 mixture, with a CH4 volume fraction of 40% and a flow rate of 150Nm³. 3 / min.

[0039] The single circumferential slit width is 2.5 mm, the CO2 pressure is 1 MPa, and the flow rate is 80 Nm³. 3 / min air supply for 20s, then 120Nm 3 Supply air at 20 seconds per minute, and repeat this cycle until the blowing process is complete.

[0040] The top-blown oxygen lance supplies CO2+O2, with a supply intensity of 2.0–3.0 Nm³. 3 / min·t iron.

[0041] The molten iron temperature is above 1300℃, and the CO2 volume fraction is controlled at 50%. The molten iron temperature is below 1250℃, and the CO2 volume fraction is controlled at 25%. When the temperature is between the two, the CO2 volume fraction is controlled at 40%.

[0042] The lance position is controlled at 1.7-2.0m. Within 2 minutes of the oxygen lance starting to blow, 22kg / t of coolant is added, and the blowing is carried out until the final temperature is below 1390℃.

[0043] By making full use of bottom-blowing elements and gas supply methods, the dynamics and temperature control of the molten pool are enhanced, and the vanadium oxidation rate is 90.1%. Compared with the traditional combined blowing converter for vanadium extraction, the vanadium oxidation rate is increased by 2.1%, and the economic benefit generated per ton of vanadium-containing molten iron is 2.1 yuan.

[0044] The above are the embodiments listed in this example. However, this example is not limited to the optional embodiments described above. Those skilled in the art can arbitrarily combine the above methods to obtain other various embodiments. Anyone can derive other various forms of embodiments based on the inspiration of this example. The above specific embodiments should not be construed as limiting the scope of protection of this example. The scope of protection of this example should be determined by the claims, and the specification can be used to interpret the claims.

Claims

1. A method for enhancing vanadium extraction in a converter, characterized in that: The vanadium-containing molten iron is added to the vanadium extraction converter. After the converter is shaken, gas is supplied from the bottom. The bottom blowing element of the bottom gas supply adopts a combination mode of single ring slit and central cluster tube. The single ring slit is sleeved outside the central cluster tube. The central cluster tube is circulated with CO2 and CH4, and the single ring slit is circulated with CO2. The single ring slit is controlled by pulse.

2. The method for enhanced vanadium extraction in a converter according to claim 1, characterized in that: The space between the central bundle tubes is filled with magnesium-carbon refractory material, and both the central bundle tubes and the single circumferential seam are stainless steel tubes.

3. The method for enhanced vanadium extraction in a converter according to claim 1, characterized in that: The central bundle tube has a diameter of 2-3 mm and a wall thickness of 1-2 mm.

4. The method for enhanced vanadium extraction in a converter according to claim 1, characterized in that: The pressure of the central bundle tube is 0.7~1MPa.

5. The method for enhanced vanadium extraction in a converter according to claim 1, characterized in that: The volume fraction of CH4 in the central collector tube is 25-40%, and the flow rate of the central collector tube is 130-150 Nm³. 3 / min.

6. The method for enhanced vanadium extraction in a converter according to claim 1, characterized in that: The pressure of the single ring seam is 0.7~1MPa, and the width of the single ring seam is 1~2.5mm.

7. The method for enhanced vanadium extraction in a converter according to claim 1, characterized in that: The pulse control specifically refers to a flow rate of 60~80 Nm. 3 / min air supply for 20s, then 100~120Nm 3 Supply air at 20 seconds per minute, and repeat this cycle until the blowing process is complete.

8. The method for enhanced vanadium extraction in a converter according to claim 1, characterized in that: It also includes top blowing, which supplies CO2 and O2 at a supply intensity of 2.0–3.0 Nm. 3 / min·t iron.

9. A method for enhancing vanadium extraction in a converter according to claim 8, characterized in that: When the molten iron temperature is above 1300℃, the volume fraction of top-blown CO2 should be controlled at 40~50%; when the molten iron temperature is below 1250℃, the volume fraction of top-blown CO2 should be controlled at 15~25%; and when the temperature is between the two, the volume fraction of top-blown CO2 should be controlled at 25~40%.

10. A method for enhancing vanadium extraction in a converter according to claim 8, characterized in that: The position of the top-blown oxygen lance is controlled at 1.7-2.0m. Within 2 minutes of starting the oxygen lance, 15-22 kg / t of coolant is added to the lance, and the smelting is carried out until the final temperature is below 1390℃.

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