A blast furnace smelting method based on vanadium titanite

Abstract

This invention relates to the field of blast furnace smelting technology and discloses a blast furnace smelting method based on vanadium-titanium ore. The method includes: adding iron ore and coke to a blast furnace for blast furnace smelting; wherein the iron ore comprises vanadium-titanium ore, and the content of vanadium-titanium ore in the iron ore is >70%; during the blast furnace smelting process, controlling the binary basicity of the slag to be 1.08–1.15 and the ternary basicity to be 1.4–1.45. Through the above scheme, this invention reduces the dependence of blast furnace smelting on imported ore and lowers the production cost of blast furnace smelting, while ensuring the fluidity of the slag and the quality of pig iron, thus bringing greater economic benefits to steel production.

Description

Technical Field

[0001] This invention relates to the field of blast furnace smelting technology, and in particular to a blast furnace smelting method based on vanadium-titanium ore. Background Technology

[0002] Blast furnace smelting is a typical "three-high" process, characterized by high resource consumption, high energy consumption, and high emissions. Production costs, material and energy consumption, and carbon emissions account for more than 70% of the total costs in steel enterprises. Effectively reducing pig iron costs is the foundation for improving the market competitiveness of steel enterprises.

[0003] In the cost structure of pig iron, the cost of ore blending accounts for more than 60%. my country's ironmaking industry has long relied heavily on imported ore, severely restricting the production, operation, and profitability of Chinese steel companies. The Panzhihua-Xichang region, Xinjiang, and Hebei province in China have abundant vanadium-titanium magnetite resources. Adding a certain amount of vanadium-titanium ore during blast furnace smelting can effectively reduce production costs and dependence on imported ore. However, using vanadium-titanium ore in smelting results in a certain level of titanium dioxide in the blast furnace slag, significantly affecting the blast furnace smelting process and slag properties. Typical effects include increased slag volume, slag thickening, and decreased fluidity, impacting the technical and economic indicators of the blast furnace to varying degrees.

[0004] Therefore, in the blast furnace smelting process, it is of great significance to increase the proportion of vanadium-titanium ore fed into the furnace without affecting the main technical and economic indicators of the blast furnace, so as to reduce dependence on imported ore and reduce production costs. This is crucial to my country's defense, aerospace, new energy and other industrial chains. Summary of the Invention

[0005] In view of this, the present invention proposes a blast furnace smelting method based on vanadium-titanium ore, which solves the technical problems of high dependence on imported ore and high production costs in the existing blast furnace smelting process.

[0006] On one hand, embodiments of the present invention provide a blast furnace smelting method based on vanadium-titanium ore. The blast furnace smelting method based on vanadium-titanium ore includes: adding iron ore and coke to a blast furnace for blast furnace smelting, wherein the iron ore includes vanadium-titanium ore and the content of the vanadium-titanium ore in the iron ore is >70%; during the blast furnace smelting process, the binary basicity of the slag is controlled to be 1.08~1.15 and the ternary basicity is controlled to be 1.4~1.45.

[0007] In some embodiments, the step of adding iron ore and coke to the blast furnace for blast furnace smelting includes adding iron ore and coke to the blast furnace at a load multiple of 4 to 5 for blast furnace smelting.

[0008] In some embodiments, the average particle size of the coke is 51 mm to 53 mm.

[0009] In some embodiments, the blast furnace smelting method based on vanadium-titanium ore further includes controlling the coke heat intensity to be ≥61% during the blast furnace smelting process.

[0010] In some embodiments, the step of controlling the coke thermal intensity ≥61% includes controlling the coke thermal intensity within the range of 61% to 65%.

[0011] In some embodiments, the blast furnace smelting method based on vanadium-titanium ore further includes: during the blast furnace smelting process, blowing high-temperature compressed air into the blast furnace.

[0012] In some embodiments, the temperature of the high-temperature compressed air is in the range of 1100°C to 1250°C.

[0013] In some embodiments, the blast furnace smelting method based on vanadium-titanium ore further includes controlling the oxygen enrichment rate to be ≥5% during the blast furnace smelting process.

[0014] In some embodiments, the step of controlling the oxygen enrichment rate ≥ 5% includes controlling the oxygen enrichment rate within the range of 5% to 10%.

[0015] In some embodiments, the step of controlling the oxygen enrichment rate ≥5% includes: adding pure oxygen to the high-temperature compressed air to control the oxygen enrichment rate ≥5%.

[0016] The present invention has at least the following beneficial effects: This invention provides a blast furnace smelting method based on vanadium-titanium ore. By adding iron ore and coke to the blast furnace at a certain load ratio and controlling the average particle size of the coke, the method ensures complete combustion of the coke and improves combustion efficiency. Furthermore, by controlling the binary basicity of the slag to 1.08–1.15 and the ternary basicity to 1.4–1.45, the method ensures the fluidity of the slag and the quality of pig iron even when the vanadium-titanium ore content in the iron ore is >70%. This reduces the dependence of blast furnace smelting on imported ore, lowers the production cost of blast furnace smelting, and brings greater economic benefits to steel production. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained based on these drawings without creative effort.

[0018] Figure 1 A flowchart of a blast furnace smelting method based on vanadium-titanium ore is provided for an embodiment of the present invention; Figure 2 A flowchart of another blast furnace smelting method based on vanadium-titanium ore provided in an embodiment of the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to specific examples and the accompanying drawings.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. For example, terms such as “length,” “width,” “upper,” “lower,” “left,” “right,” “front,” “rear,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” and “outer” indicate orientations or positions based on the orientations or positions shown in the accompanying drawings and are for ease of description only, and should not be construed as limiting the technical solution.

[0021] The terms "comprising" and "having," and any variations thereof, used in the specification, claims, and accompanying drawings of this invention are intended to cover non-exclusive inclusion; the terms "first," "second," etc., used in the specification, claims, and accompanying drawings are used to distinguish different objects, not to describe a particular order. "A plurality of" means two or more, unless otherwise explicitly specified.

[0022] In the description and claims of this invention and the foregoing drawings, when an element is referred to as "fixed to," "mounted to," "disposed on," or "connected to" another element, it can be located directly or indirectly on that other element. For example, when an element is referred to as "connected to" another element, it can be directly or indirectly connected to that other element.

[0023] The iron ore resources in the Panxi region are high-titanium vanadium-titanium magnetite (TiO2 content is 10-12%), which is a unique resource of great strategic value in my country. Its smelting process bears the important responsibility of extracting a variety of key metals such as iron, vanadium, and titanium, and is crucial to ensuring the security of industrial chains such as national defense, aerospace, and new energy.

[0024] Due to the unique composition of vanadium-titanium ore in the Panxi region—a ore with a close symbiotic relationship between iron and titanium, where titanium exists in solid solution within titanomagnetite and vanadium substitutes for iron in isomorphous forms—it is a special ore that is difficult to process and refine. Introducing a certain proportion of vanadium-titanium ore as a smelting raw material during blast furnace smelting can reduce dependence on imported ore to some extent and lower production costs.

[0025] After decades of technological breakthroughs, the proportion of high-titanium vanadium-titanium ore in the ore structure of Panzhihua Iron and Steel Group (Pangang) has reached 70%. To further reduce reliance on expensive imported ore and lower production costs, it is necessary to further increase the proportion of vanadium-titanium ore used. However, this further increase leads to a corresponding increase in the sulfur (S) content in the molten iron, reducing the quality of pig iron and decreasing the fluidity of the slag. Therefore, in the blast furnace smelting process, it is of great significance to further increase the proportion of vanadium-titanium ore fed into the furnace without affecting the main technical and economic indicators of the blast furnace, thereby reducing dependence on imported ore and lowering production costs. This is crucial for my country's defense, aerospace, and new energy industrial chains.

[0026] The present invention will now be described in detail with reference to the embodiments and accompanying drawings.

[0027] The first aspect of this invention provides a blast furnace smelting method based on vanadium-titanium ore, such as... Figure 1 As shown, the blast furnace smelting method based on vanadium-titanium ore includes steps S10 and S20.

[0028] S10. Add iron ore and coke to the blast furnace for blast furnace smelting.

[0029] In this embodiment, iron ore and coke can be added to the blast furnace. Compressed air is blown into the lower part of the blast furnace hearth to burn the coke. After combustion, a high-temperature reducing gas with CO (25-35%) as its main component is generated. The rising reducing gas undergoes a series of physicochemical reactions with the descending iron ore, ultimately forming pig iron. The iron ore includes vanadium-titanium ore, and the vanadium-titanium ore content in the iron ore is >70%.

[0030] In one specific embodiment, during blast furnace smelting, iron ore and coke can be added to the blast furnace at a load multiple of 4 to 5. For example, if the coke load is 4 t / t, then for every 1 ton of coke added, 4 tons of iron ore are added. If the coke load is 5 t / t, then for every 1 ton of coke added, 5 tons of ore are added.

[0031] In one specific embodiment, the average particle size of the coke is 51 mm to 53 mm.

[0032] Because the proportion of vanadium-titanium ore used in the blast furnace smelting process is high, the amount of slag produced is also relatively large. Therefore, in order to ensure the permeability of the molten metal and improve the combustion efficiency in the furnace during the smelting process, a 1000m... 3 Blast furnaces of grade 1 and above can control the average particle size of coke within the range of 51mm to 53mm.

[0033] S20. During the blast furnace smelting process, the binary basicity of the slag is controlled to be 1.08 to 1.15, and the ternary basicity is controlled to be 1.4 to 1.45.

[0034] The molten iron produced in a blast furnace contains a certain amount of sulfur (S), which is a major harmful element causing hot brittleness in steel. The main factor affecting the desulfurization effect of the blast furnace is the slag basicity (the mass fraction ratio of CaO / SiO2 is called binary basicity, or R2 for short). To ensure the quality of pig iron (mainly by controlling and reducing the S content), R2 usually needs to be controlled between 1.15 and 1.25. However, because the iron ore used in the blast furnace smelting of this invention has a high vanadium-titanium ore ratio, the slag has poor fluidity and high TiO2 content. Therefore, the binary basicity (R2) needs to be controlled to be lower, within the range of 1.08 to 1.15, to ensure the quality of pig iron. In a specific embodiment, when the TiO2 content in the slag is >20%, R2 is controlled between 1.08 and 1.15. Within this basicity range, TiO2 mainly exhibits an acidic state and will not adversely affect the fluidity of the slag.

[0035] In some specific embodiments, R2 can be 1.08, 1.09, 1.1, 1.11, 1.12, 1.13, 1.14 or 1.15.

[0036] Because R2 is relatively low, the desulfurization capacity of titanium-containing slag is affected, resulting in uncontrolled sulfur content in pig iron. To compensate for this, the reduced desulfurization capacity is compensated for by increasing the MgO content in the slag. This is achieved by controlling the ternary basicity (the mass fraction ratio of CaO + MgO / SiO2, referred to as ternary basicity R3) within a higher multiple range, thus ensuring pig iron quality. This allows for the achievement of a certain proportion of vanadium-titanium ore used in iron ore while maintaining pig iron quality. R3 can be controlled within the range of 1.4 to 1.45.

[0037] In some specific embodiments, R3 can be 1.4, 1.41, 1.42, 1.43, 1.44 or 1.45.

[0038] In this embodiment of the invention, binary basicity can be controlled by adjusting the amount of calcium flux such as limestone and quicklime, as well as the basicity of sinter and the structure of the furnace charge (e.g., the ratio of sinter to pellets). Based on the binary basicity, the MgO content can be controlled by adjusting the amount of magnesium flux such as dolomite, thereby achieving ternary basicity control.

[0039] In this embodiment of the invention, by adding iron ore and coke to the blast furnace at a certain load ratio and controlling the average particle size of the coke, the complete combustion of the coke can be ensured, improving combustion efficiency. Furthermore, by controlling the binary basicity of the slag to 1.08–1.15 and the ternary basicity to 1.4–1.45, the slag fluidity and pig iron quality can be ensured even when the vanadium-titanium ore content in the iron ore is >70%. This reduces the reliance of blast furnace smelting on imported ore, lowers the production cost of blast furnace smelting, and brings greater economic benefits to steel production.

[0040] In some embodiments, the blast furnace smelting method based on vanadium-titanium ore provided by the present invention may include steps S10 and S20, and may also include steps S30 and / or S40 and / or S50. Figure 2 There is a case where steps S30, S40, and S50 are included simultaneously.

[0041] S30. During the blast furnace smelting process, the thermal intensity of coke shall be controlled to be ≥61%.

[0042] Due to the unique composition of vanadium-titanium ore in the Panxi region—a ore with a close symbiotic relationship between iron and titanium, where titanium exists as a solid solution within titanomagnetite and vanadium isomorphously replacing iron—it is a special ore that is difficult to process and refine. During the smelting process in the blast furnace, which is primarily in a reducing atmosphere, a certain amount of high-melting-point Ti(C,N) compounds (melting point 3000℃) will be generated. These high-melting-point Ti(C,N) compounds dispersed in the slag will worsen its fluidity, severely impacting the blast furnace's production efficiency. To reduce the impact of high-melting-point Ti(C,N) compounds on the smelting process, vanadium-titanium ore smelting requires improving the combustion efficiency of coke in the furnace.

[0043] Coke thermal strength (CSR) is a key indicator for measuring coke's ability to withstand thermal stress and chemical erosion during blast furnace smelting. Its significance lies primarily in two aspects: First, ensuring smooth blast furnace operation. Coke acts as the skeleton supporting the furnace charge; high thermal strength prevents it from crumbling and pulverizing at high temperatures, maintaining the permeability of the charge column and avoiding uneven airflow distribution or furnace condition fluctuations. Second, optimizing fuel consumption. High thermal strength coke has lower reactivity, reducing losses from CO2 gasification reactions, thereby lowering the coke-to-coke ratio (coke consumption per ton of iron) and saving production costs. Therefore, to improve the combustion efficiency of coke in the furnace, increase the amount of vanadium-titanium ore used in iron ore, and save production costs, the coke thermal strength can be controlled to ≥61%.

[0044] In one specific embodiment, the coke thermal intensity is controlled within the range of 61% to 65% to balance the combustion efficiency and production cost of blast furnace smelting. More specifically, the coke thermal intensity can be controlled at 61%, 62%, 63%, 64%, or 63%.

[0045] In one specific embodiment, for 1000m 3 Blast furnaces of grade 1 and above can control the coke heat intensity within the range of 61% to 65% and the average coke particle size within the range of 51mm to 53mm. This allows for increased use of vanadium-titanium ore in the iron ore while ensuring good liquid and gas permeability within the furnace during the smelting process, improving coke combustion efficiency, and saving production costs. More specifically, the average coke particle size can be controlled to be 51mm, 52mm, or 53mm.

[0046] S40. During the blast furnace smelting process, high-temperature compressed air is blown into the blast furnace.

[0047] During blast furnace smelting, high-temperature compressed air heated to 1100℃-1250℃ can be blown into the blast furnace to improve the combustion effect of coke. More specifically, the temperature of the high-temperature compressed air can be controlled at 1100℃, 1150℃, 1200℃, or 1250℃.

[0048] S50. During the blast furnace smelting process, the oxygen enrichment rate shall be controlled to be ≥5%.

[0049] During blast furnace smelting, the unavoidable over-reduction of TiO2 can lead to the formation of high-melting-point titanium nitride (TiNC). Therefore, it is necessary to increase the oxygen potential in the hearth to suppress the over-reduction of TiO2. Consequently, in actual blast furnace smelting, the oxygen enrichment rate needs to be controlled at ≥5%, thereby increasing the oxygen potential in the hearth and improving the smelting intensity to achieve rapid inflow and outflow.

[0050] In one specific embodiment, the oxygen enrichment rate can be controlled to be ≥5% by adding a certain proportion of oxygen to the high-temperature compressed air.

[0051] In one specific embodiment, the oxygen enrichment rate can be controlled within the range of 5% to 10% to increase the oxygen potential in the hearth and improve the smelting intensity, achieving rapid inflow and outflow. More specifically, the oxygen enrichment rate can be controlled at 5%, 6%, 7%, 8%, 9%, or 10%.

[0052] The blast furnace smelting method based on vanadium-titanium ore provided in this embodiment of the invention also includes periodically discharging the vanadium-containing pig iron generated during smelting out of the blast furnace to complete the smelting process.

[0053] The blast furnace smelting method for vanadium-titanium ore provided by the present invention will be described below through specific embodiments. It should be understood that the following embodiments are only used to explain the present invention and are not intended to limit the present invention.

[0054] In related technologies, due to limitations in vanadium-titanium ore smelting technology, the proportion of vanadium-titanium ore in a certain blast furnace for smelting vanadium-titanium magnetite has been maintained at 70% for a long time, and the slag (TiO2) has been stable at 22-22.5%.

[0055] Example 1 By using the blast furnace smelting method for vanadium-titanium ore provided by this invention, and by controlling the coke heat intensity at 61.5%, the oxygen enrichment rate at 5.2%, the binary basicity R2 at 1.11 times, and the ternary basicity R3 at 1.41 times, the proportion of vanadium-titanium ore in the iron ore reaches more than 71.5%, the slag (TiO2) reaches 23.2%, and the cost of pig iron is reduced by 59 yuan per ton of pig iron.

[0056] In this embodiment, by controlling the coke thermal intensity at 61.5% and the oxygen enrichment rate at 5.2%, the coke thermal intensity and oxygen enrichment rate are improved, thereby enhancing the smelting degree and effectively improving production efficiency. By controlling the binary basicity R2 to 1.11 times and the ternary basicity R3 to 1.41 times, the slag fluidity and pig iron quality are ensured, thus optimizing the blast furnace ore blending structure.

[0057] This embodiment, through the above-described scheme, ensures slag fluidity and pig iron quality while reducing pig iron costs by increasing the proportion of vanadium-titanium ore used in the iron ore.

[0058] Example 2 By using the blast furnace smelting method for vanadium-titanium ore provided by this invention, and by controlling the coke heat intensity at 64%, the oxygen enrichment rate at 7%, the binary basicity R2 at 1.10 times, and the ternary basicity R3 at 1.42 times, the proportion of vanadium-titanium ore in the iron ore reaches more than 75%, the slag (TiO2) reaches 24.5%, and the cost of pig iron is reduced by 75 yuan per ton of iron.

[0059] In this embodiment, by controlling the coke thermal intensity at 64% and the oxygen enrichment rate at 7%, the coke thermal intensity and oxygen enrichment rate are further improved, thereby enhancing the smelting degree and effectively improving production efficiency. By controlling the binary basicity R2 to 1.10 times and the ternary basicity R3 to 1.42 times, the slag fluidity and pig iron quality are ensured, thus optimizing the blast furnace ore blending structure.

[0060] This embodiment, through the above-described scheme, further improves the proportion of vanadium-titanium ore used in iron ore while ensuring slag fluidity and pig iron quality, and reduces pig iron costs.

[0061] Example 3 By using the blast furnace smelting method for vanadium-titanium ore provided by this invention, and by controlling the coke heat intensity at 65%, the oxygen enrichment rate at 8%, the binary basicity R2 at 1.09 times, and the ternary basicity R3 at 1.43 times, the proportion of vanadium-titanium ore in the iron ore reaches more than 80%, the slag (TiO2) reaches 25.8%, and the cost of pig iron is reduced by 86 yuan per ton of pig iron.

[0062] In this embodiment, by controlling the coke heat intensity at 65% and the oxygen enrichment rate at 8%, the coke heat intensity and oxygen enrichment rate are further improved, thereby enhancing the smelting degree and effectively improving production efficiency. By controlling the binary basicity R2 to 1.09 times and the ternary basicity R3 to 1.43 times, the slag fluidity and pig iron quality are ensured, thus optimizing the blast furnace ore blending structure.

[0063] This embodiment, through the above-described scheme, further improves the proportion of vanadium-titanium ore used in iron ore while ensuring slag fluidity and pig iron quality, and reduces pig iron costs.

[0064] The technical features of the above embodiments can be combined in any way. For the sake of brevity, 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.

[0065] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A blast furnace smelting method based on vanadium-titanium ore, characterized in that, include: Iron ore and coke are added to a blast furnace for blast furnace smelting, wherein the iron ore includes vanadium-titanium ore and the content of the vanadium-titanium ore in the iron ore is >70%; During the blast furnace smelting process, the binary basicity of the slag is controlled to be 1.08 to 1.15, and the ternary basicity is controlled to be 1.4 to 1.

45.

2. The method according to claim 1, characterized in that, The step of adding iron ore and coke into the blast furnace for blast furnace smelting includes: Iron ore and coke are added to the blast furnace at a load ratio of 4 to 5 for blast furnace smelting.

3. The method according to claim 1, characterized in that, The average particle size of the coke is 51 mm to 53 mm.

4. The method according to claim 1, characterized in that, Also includes: During the blast furnace smelting process, the thermal intensity of the coke is controlled to be ≥61%.

5. The method according to claim 4, characterized in that, The step of controlling the coke thermal intensity to ≥61% includes: Control the thermal intensity of coke within the range of 61% to 65%.

6. The method according to claim 1, characterized in that, Also includes: During the blast furnace smelting process, high-temperature compressed air is blown into the blast furnace.

7. The method according to claim 6, characterized in that, The temperature of the high-temperature compressed air is in the range of 1100℃-1250℃.

8. The method according to claim 6, characterized in that, Also includes: During the blast furnace smelting process, the oxygen enrichment rate is controlled to be ≥5%.

9. The method according to claim 8, characterized in that, The steps for controlling the oxygen enrichment rate to ≥5% include: The oxygen enrichment rate should be controlled within the range of 5% to 10%.

10. The method according to claim 8, characterized in that, The steps for controlling the oxygen enrichment rate to ≥5% include: Pure oxygen is added to the high-temperature compressed air to control the oxygen enrichment rate to ≥5%.

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