Blast furnace smelting method for schreyerite with low magnesium-aluminum ratio

Abstract

The invention discloses a blast furnace smelting method for schreyerite with a low magnesium-aluminum ratio, relates to the technical field of blast furnace smelting in the technical field of schreyerite, and solves the problems that an existing blast furnace vanadium titano-magnetite smelting method is not suitable for smelting under the condition of the low magnesium-aluminum ratio and the smelting effect is poor. Slag components are accurately regulated and controlled; furnace temperature is controlled, and the molten iron temperature is controlled within a first preset parameter; air supply is controlled; and controlling the coke quality and smelting to obtain a finished product. By adjusting crude fuel, slag is accurately regulated and controlled, and slagging, the molten iron temperature, the air supply system and the coke quality are adjusted; the method is suitable for a schreyerite blast furnace smelting method under the condition of low magnesium-aluminum ratio, the slag performance is excellent, and the desulfurization effect is good. And the generation of high-melting-point minerals in the furnace slag is greatly reduced by precisely regulating and controlling the components of the furnace slag, especially the cooperative regulation and control of low magnesium-aluminum ratio and binary alkalinity. And the slag fluidity is greatly improved, slag-iron separation is smooth, and the production efficiency of the blast furnace is improved.

Description

Technical Field

[0001] This invention relates to the field of blast furnace smelting technology for vanadium-titanium ore, and specifically to a blast furnace smelting method for vanadium-titanium ore with a low magnesium-to-aluminum ratio. Background Technology

[0002] In the current vanadium-titanium ore smelting field, the main process involves preparing a high-basicity sinter from vanadium-titanium concentrate powder, ordinary ore powder, recycled materials, quicklime powder, and dolomite powder. The vanadium-titanium concentrate powder is then used to produce oxide pellets. The sinter, pellets, and a small amount of lump ore are then added to a blast furnace along with coke in a specific ratio. The coke is burned in the lower part of the furnace to generate reducing gases, achieving ore reduction, melting, and slag-iron separation. To control the appropriate slag basicity and magnesium-aluminum ratio, quicklime powder and dolomite powder need to be added to the sinter. However, increasing the amount of solvent added inevitably dilutes the sinter grade and increases ore consumption. To improve the sinter grade, the magnesium-aluminum ratio in the slag should be minimized while maintaining suitable slag fluidity, and the amount of dolomite added should be reduced accordingly.

[0003] Slag performance issues: The inherent characteristics of vanadium-titanium ore mean that high-melting-point titanates and other substances are easily formed in the slag. These high-melting-point substances will still increase the melting temperature and viscosity of the slag. When the Al2O3 content in the slag is too high and the MgO content is relatively low (i.e., low magnesium-aluminum ratio), the slag fluidity deteriorates, slag-iron separation becomes difficult, and foamy slag is easily generated, which seriously affects the smooth operation of the blast furnace and increases smelting costs.

[0004] The challenge of balancing desulfurization and slag performance: Vanadium-titanium ore typically has a high sulfur content. In low magnesium-aluminum ratio smelting, excessively adjusting the slag composition solely to improve slag fluidity can lead to improper control of the slag's binary basicity. This will reduce the effective desulfurization ions (O²⁻) in the slag. - Insufficient sulfur concentration reduces the qualified rate of sulfur content in molten iron. To ensure the quality of molten iron, it is necessary to increase the furnace temperature, which in turn leads to increased fuel consumption and coke ratio, thus increasing the production costs of enterprises.

[0005] The challenge of controlling titanium reduction: Under low magnesium-aluminum ratios, the reduction of titanium is not sufficiently suppressed. The reducing environment inside the blast furnace makes it easy for titanium to combine with carbon and nitrogen to form high-melting-point compounds such as titanium carbide (TiC) and titanium nitride (TiN). These compounds deposit in the hearth, affecting hearth activity, hindering smooth blast furnace operation, and may even cause serious problems such as hearth buildup.

[0006] Limited adaptability of furnace charge: Existing low magnesium-aluminum ratio smelting processes have poor adaptability to vanadium-titanium ores from different origins and with different compositions. Due to the complex and highly variable composition of vanadium-titanium ores, existing process parameters are difficult to adjust flexibly to adapt to various ore sources, thus limiting the widespread utilization of vanadium-titanium ore resources.

[0007] It is evident that existing blast furnace methods for smelting vanadium-titanium magnetite are not suitable for smelting under medium to low magnesium-aluminum ratio conditions, resulting in poor slag performance, inadequate desulfurization, difficulty in controlling titanium reduction, and insufficient adaptability to different vanadium-titanium ores. Summary of the Invention

[0008] The purpose of this invention is to address the problem that existing blast furnace methods for smelting vanadium-titanium magnetite are unsuitable for smelting under low magnesium-aluminum ratio conditions, resulting in poor smelting efficiency. This invention provides a blast furnace smelting method for vanadium-titanium ore suitable for low magnesium-aluminum ratio conditions.

[0009] To achieve the above objectives, the present invention specifically adopts the following technical solution: A blast furnace smelting method for vanadium-titanium ore with a low magnesium-to-aluminum ratio includes the following steps: S1. Add raw materials and fuel to the blast furnace for charging; S2, Precise control of slag composition; S3. Control the furnace temperature and keep the molten iron temperature within the first preset parameter. S4, Control air supply; S5. Control the quality of coke and smelt to obtain the finished product.

[0010] Furthermore, the raw materials are sintered ore, pellets, and raw ore.

[0011] Furthermore, the raw materials, by weight, include 47-50 parts of sintered ore, 45-50 parts of pelletized ore, and 3-6 parts of raw ore.

[0012] Furthermore, the precise control of slag composition in S2 includes controlling the ratio of MgO to Al2O3 in the slag to be 0.58-0.63.

[0013] Furthermore, the precise control of slag composition in S2 also includes controlling the binary basicity CaO / SiO2 in the slag to be 1-1.2.

[0014] Furthermore, the precise control of slag composition in S2 also includes controlling the proportion of Al2O3 in the slag content to be less than 14.5%.

[0015] Furthermore, the first preset parameter is 1430-1460℃.

[0016] Furthermore, controlling the air supply includes accurately controlling the equal area matrix division of the furnace throat, setting the ore drop point distribution range, and controlling the furnace throat temperature between 60 and 120°C.

[0017] Furthermore, controlling the air supply also includes symmetrically arranging the tuyeres to promote the rational distribution of airflow inside the furnace and ensure smooth furnace operation.

[0018] Furthermore, the control of coke quality is as follows: coke feeding speed ≤50kg / s; reactivity ≤28%; post-reaction strength ≥62%; average particle size 48-52mm; M40 ≥86; M10 ≤6.0; and dry quenching coke usage ratio ≥70%.

[0019] Compared with the prior art, the advantages of the present invention are as follows: 1. The present invention relates to a blast furnace smelting method for vanadium-titanium ore with a low magnesium-aluminum ratio, which adjusts the raw materials and fuels and precisely controls the slag formation, molten iron temperature, blast system, and coke quality; it is applicable to blast furnace smelting of vanadium-titanium ore under low magnesium-aluminum ratio conditions, with excellent slag performance and good desulfurization effect.

[0020] By precisely controlling the slag composition, especially the synergistic control of low magnesium-aluminum ratio and binary basicity, the formation of high-melting-point minerals in the slag was significantly reduced. The slag viscosity was significantly reduced, the fluidity was greatly improved, slag-iron separation was smoother, the generation of foamy slag was effectively reduced, and the production efficiency of the blast furnace was improved.

[0021] Furthermore, efficient desulfurization reduces costs: under conditions of low magnesium-aluminum ratio and optimized slag composition, it not only ensures sufficient (O²⁺) in the slag. - It is used for desulfurization reaction and also improves desulfurization kinetics by improving slag fluidity.

[0022] The sulfur content of molten iron is guaranteed to meet standards, avoiding an increase in coke ratio due to increased furnace temperature for desulfurization, thus reducing smelting costs. Optimized slag properties and smelting processes reduce slag volume, decrease iron loss, and improve iron resource utilization, which helps enterprises achieve energy conservation, emission reduction, and improved economic efficiency.

[0023] The blast furnace smelting method for low magnesium-aluminum ratio vanadium-titanium ore involved in this invention can adapt well to vanadium-titanium ores from different origins and with different compositions by flexibly adjusting the slag composition and operating parameters, thus expanding the utilization range of vanadium-titanium ore resources and providing enterprises with a wider range of raw material choices.

[0024] 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 some embodiments of the present invention, but not all embodiments.

[0025] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. Detailed Implementation

[0026] A blast furnace smelting method for vanadium-titanium ore with a low magnesium-to-aluminum ratio includes the following steps: S1. Add raw materials and fuel to the blast furnace for charging; S2, Precise control of slag composition; S3. Control the furnace temperature and keep the molten iron temperature within the first preset parameter. S4, Control air supply; S5. Control the quality of coke and smelt to obtain the finished product.

[0027] Understandably, by adjusting the raw materials and fuels, the slag formation, molten iron temperature, air supply system, and coke quality can be precisely controlled; this method is suitable for blast furnace smelting of vanadium-titanium ore under low magnesium-aluminum ratio conditions, with excellent slag performance and good desulfurization effect.

[0028] In some embodiments of the present invention, the raw materials are sintered ore, pellets, and raw ore.

[0029] In some embodiments of the present invention, the raw materials and fuels, by weight, include 47-50 parts of sintered ore, 45-50 parts of pellets, and 3-6 parts of raw ore.

[0030] Stabilize the furnace charge structure and improve the stability of ore feeding into the furnace. Pelletized ore has uniform particle size, high strength, good metallurgical properties, high grade, good quality stability, low sulfur content, low process emissions, and low smelting costs. By adjusting the raw materials, a furnace charge structure with high production quality and a high proportion of pelletized ore in the raw materials can be determined.

[0031] In some embodiments of the present invention, the precise control of slag composition in S2 includes controlling the ratio of MgO to Al2O3 in the slag to be 0.58-0.63.

[0032] In some embodiments of the present invention, the precise control of slag composition in S2 further includes controlling the binary basicity CaO / SiO2 in the slag to be 1-1.2.

[0033] In some embodiments of the present invention, when the magnesium-aluminum ratio (the ratio of MgO to Al2O3) is in the range of 0.58-0.63, the binary basicity of the slag is controlled at 1.08-1.18. When the magnesium-aluminum ratio is taken at the upper limit, the basicity of the slag can be appropriately reduced to the lower limit.

[0034] In some embodiments of the present invention, the precise control of slag composition in S2 further includes controlling the proportion of Al2O3 in the slag content to be less than 14.5%.

[0035] By precisely controlling the slag composition, especially the synergistic control of low magnesium-aluminum ratio and binary basicity, the formation of high-melting-point minerals in the slag was significantly reduced. The slag viscosity was significantly reduced, the fluidity was greatly improved, slag-iron separation was smoother, the generation of foamy slag was effectively reduced, and the production efficiency of the blast furnace was improved.

[0036] Furthermore, efficient desulfurization reduces costs: under conditions of low magnesium-aluminum ratio and optimized slag composition, it not only ensures sufficient (O²⁺) in the slag. - It is used for desulfurization reactions and also improves desulfurization kinetics by enhancing slag fluidity. The sulfur content of molten iron is guaranteed to meet standards, avoiding the increase in coke ratio caused by increasing furnace temperature for desulfurization, and reducing smelting costs.

[0037] Stabilizing the pellets reduces their rolling and facilitates slag and iron discharge, thereby further mitigating the negative impacts that may arise from increasing the proportion of pellets in the furnace charge structure. It is evident that this invention addresses the potential defects of high-proportion pellets by controlling the quality of the finished product while increasing the proportion of pellets in the raw materials through multiple dimensions. It also solves the problem of low pellet proportions in the raw materials in existing blast furnace smelting methods for vanadium-titanium magnetite, making the blast furnace smelting method for vanadium-titanium magnetite involved in this invention superior, reducing production costs, and possessing economic value.

[0038] In some embodiments of the present invention, MnO is appropriately introduced into the slag. The MnO content in the slag is controlled to be between 0.75% and 1.10%.

[0039] The chemical reaction between it and titanium is used to inhibit the over-reduction of titanium. The specific reaction formula is as follows: 2(MnO)+[Ti]=2[Mn]+(TiO2) The presence of MnO not only allows it to react directly with titanium, but also weakens the reduction effect of C on (TiO2) to some extent, increases the oxygen potential in the lower part of the blast furnace, further inhibits titanium reduction, and effectively reduces the deposition of titanium compounds in the hearth. Process parameter adjustments: Combined with optimized blast parameters and furnace temperature control, over-reduction of titanium is further suppressed.

[0040] In some embodiments of the present invention, the first preset parameter is 1430-1460℃.

[0041] Precisely controlling the furnace temperature is crucial to prevent excessive titanium reduction caused by overheating. Strictly controlling the molten iron temperature within a suitable range ensures good fluidity of the slag and iron, inhibiting titanium reduction and the formation of high-melting-point substances such as Ti(CN).

[0042] In some embodiments of the present invention, controlling the air supply includes accurately controlling the equal area matrix division of the furnace throat, setting the ore drop point distribution range, and controlling the furnace throat temperature at 60-120°C.

[0043] In some embodiments of the present invention, controlling the air supply also includes symmetrically arranging the air outlets to promote the rational distribution of airflow inside the furnace and ensure smooth furnace operation.

[0044] By precisely controlling the equal-area matrix division of the furnace throat and setting the ore drop point distribution range, the furnace throat temperature is controlled between 60 and 120℃, ensuring a uniform and reasonable airflow distribution within the furnace. The tuyeres are symmetrically laid out, and their areas are flexibly adjusted according to actual production conditions to promote a reasonable airflow distribution within the furnace and ensure smooth furnace operation.

[0045] In some embodiments of the present invention, controlling the air supply also includes appropriately increasing the oxygen content of the blower air. Oxygen enrichment can significantly improve the combustion performance of pulverized coal and the fluidity of slag, and increase the theoretical combustion temperature in front of the tuyeres; it also increases the oxidizing atmosphere in the furnace and reduces the possibility of excessive reduction of titanium.

[0046] In some embodiments of the present invention, controlling the air supply also includes precisely adjusting the wind speed and blast energy. Desheng Steel maintains the blast energy at around 12,000-16,000 kg•m / s to ensure the hearth is active and the reaction inside the furnace is more complete.

[0047] In some embodiments of the present invention, the control of coke quality is as follows: coke feeding speed ≤50kg / s; reactivity ≤28%; post-reaction strength ≥62%; average particle size 48-52mm; M40 ≥86; M10 ≤6.0; and dry quenching coke usage ratio ≥70%.

[0048] High importance is attached to coke quality, stabilizing the coke feed structure, and strengthening trough management and screening management to control the coke feeding rate to ≤50kg / s. Ensure uniform coke particle size and stable strength to avoid affecting the permeability of the blast furnace feed column and the normal progress of in-furnace reactions due to coke quality issues, creating favorable conditions for smooth blast furnace operation. Reactivity ≤28%, post-reaction strength ≥62%, average particle size 48-52mm, M40 ≥86, M10 ≤6.0, dry quenching coke usage ratio ≥70%, ensuring the skeletal function of the feed column when using small-particle sinter.

[0049] Example 1 In the smelting of vanadium-titanium iron ore, increasing the proportion of pellet ore for blast furnace smelting specifically includes the following steps: S1. Raw materials and fuels are added to the blast furnace for charging; the raw materials and fuels are sintered ore, pellets, and raw ore. The sintered ore, pellets, and raw ore, by weight percentage, comprise 47-50% sintered ore, 45-50% pellets, and 3-6% raw ore.

[0050] S2. Precisely control the slag composition; control the ratio of MgO to Al2O3 in the slag to 0.6. Control the binary basicity of the slag, CaO / SiO2, to 1.15. Control the proportion of Al2O3 in the slag content to less than 14.5%.

[0051] S3. Control the furnace temperature, keeping the molten iron temperature between 1430-1460℃; S4. Control the air supply; accurately control the equal area matrix division of the furnace throat, set the ore drop point distribution range, and control the furnace throat temperature between 60-120℃. Arrange the tuyeres symmetrically to promote the rational distribution of airflow inside the furnace and ensure smooth furnace operation.

[0052] S5. Control the quality of coke, and control the coke feeding speed to ≤50kg / s; reactivity to ≤28%, post-reaction strength to ≥62%, average particle size to 48-52mm, M40 to ≥86, M10 to ≤6.0, and the proportion of dry quenching to ≥70%. The finished product is obtained through smelting.

[0053] Example 2 Unlike Example 1, the ratio of MgO to Al2O3 in the slag is controlled at 0.58. The binary basicity (CaO / SiO2) in the slag is controlled at 1.18. The proportion of Al2O3 in the slag is controlled to be less than 14.5%. This facilitates production and the smelting of the final product.

[0054] Example 3 Unlike Example 1, the ratio of MgO to Al2O3 in the slag is controlled at 0.59. The binary basicity (CaO / SiO2) in the slag is controlled at 1.16. The proportion of Al2O3 in the slag is controlled to be less than 14.5%. This facilitates production and the smelting of the final product.

[0055] Example 4 Unlike Example 1, the ratio of MgO to Al2O3 in the slag is controlled at 0.61. The binary basicity (CaO / SiO2) in the slag is controlled at 1.14. The proportion of Al2O3 in the slag is controlled to be less than 14.5%. This facilitates production and the smelting of the final product.

[0056] Example 5 Unlike Example 1, the ratio of MgO to Al2O3 in the slag is controlled at 0.62. The binary basicity (CaO / SiO2) in the slag is controlled at 1.12. The proportion of Al2O3 in the slag is controlled to be less than 14.5%. This facilitates production and the smelting of the final product.

[0057] Example 6 Unlike Example 1, the ratio of MgO to Al2O3 in the slag is controlled at 0.63. The binary basicity (CaO / SiO2) in the slag is controlled at 1.08. The proportion of Al2O3 in the slag is controlled to be less than 14.5%. This facilitates production and the smelting of the final product.

[0058] Comparative Example 1 Conventional smelting methods were used, and the slag composition was not adjusted. Unlike Example 1, the slag composition was not adjusted.

[0059] Comparative Example 2 Unlike Example 1, the ratio of MgO to Al2O3 in the slag was controlled at 0.57. The slag basicity was controlled at 1.20. Because the magnesium-aluminum ratio was too low and the slag basicity of 1.20 was too high, the slag melting temperature reached 1395℃, and the slag viscosity was too high, which was not conducive to production.

[0060] Comparative Example 3 Unlike Example 1, the ratio of MgO to Al2O3 in the slag was controlled at 0.64, the slag basicity was controlled at 1.10, and the magnesium-aluminum ratio was controlled too high. Therefore, the amount of dolomite added in the sinter was high, and the quality of the sinter decreased due to the increase of MgO, which was not conducive to production.

[0061] Comparative Example 4 Unlike Example 1, the binary basicity (CaO / SiO2) in the slag was controlled at 1.3. Excessive slag basicity results in an excessively high melting temperature and viscous slag, which is detrimental to production.

[0062] Comparative Example 5 Unlike Example 1, the binary basicity (CaO / SiO2) in the slag was controlled at 0.9. Too low a basicity in the slag results in poor desulfurization capacity, which is detrimental to production.

[0063] Comparative Example 6 Unlike Example 1, the Al2O3 content in the slag is greater than 14.5%, which is detrimental to production.

[0064] The above embodiments are merely one implementation of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A blast furnace smelting method of low magnesium-aluminum ratio vanadium titanite, characterized by, The method comprises the following steps: S1, adding raw fuel into the blast furnace for distribution; S2, precisely controlling the composition of the slag; S3, controlling the furnace temperature, and controlling the temperature of the molten iron within a first preset parameter; S4, controlling the blast; S5, controlling the quality of the coke, and obtaining the finished product through smelting.

2. The blast furnace smelting method of low magnesium-aluminum ratio vanadium titanomagnetite according to claim 1, characterized in that: The raw fuel is sintered ore, pellet ore and raw ore.

3. A blast furnace smelting process for a low MgO / Al203 vanadium titanate ore according to claim 2, characterised in that: The raw fuel comprises, by weight fraction, sintered ore 47-50 parts, pellet ore 45-50 parts, and raw ore 3-6 parts.

4. The blast furnace smelting method of low magnesium-aluminum ratio vanadium titanomagnetite according to claim 1, characterized in that: The precise control of the composition of the slag in S2 comprises controlling the ratio of MgO to Al2O3 in the slag to be 0.58-0.

63.

5. The method according to claim 4, wherein the vanadium titano-magnetite has a low MgO / Al2O3 ratio. The precise control of the composition of the slag in S2 further comprises controlling the binary basicity CaO / SiO2 in the slag to be 1-1.

2.

6. A blast furnace smelting process for a low MgO / Al203 vanadium titanate ore according to claim 4, characterised in that: The precise control of the composition of the slag in S2 further comprises controlling the ratio of Al2O3 in the slag content to be less than 14.5%.

7. The method according to claim 1, wherein the vanadium titano-magnetite has a low MgO content. The first preset parameter is 1430-1460℃.

8. The method according to claim 1, wherein the vanadium titanomagnetite has a low MgO / Al2O3 ratio. The control of the blast comprises ensuring the equal area matrix division of the furnace throat, setting the ore drop point distribution range, and controlling the furnace throat temperature to be 60-120℃.

9. The method according to claim 1, wherein the vanadium titanomagnetite has a low MgO / Al2O3 ratio. The control of the blast further comprises symmetrically arranging the tuyeres.

10. The method of claim 1, wherein the vanadium titano-magnetite has a low magnesium-aluminum ratio. The control of the coke quality comprises controlling the coke feeding speed to be ≤50kg / s, the reactivity to be ≤28%, the strength after reaction to be ≥62%, the average particle size to be 48-52mm, M40 to be ≥86, M10 to be ≤6.0, and the dry quenching usage ratio to be ≥70%.