Blast furnace smelting method for schreyerite with high oxygen enrichment and high pellet ratio

Abstract

The invention provides a high-oxygen-enrichment high-pellet-proportion schreyerite blast furnace smelting method which comprises the following steps: for a blast furnace with smelting objects of 1200-2500m < 3 >, smelting by taking vanadium-titanium pellets and sintered ores as furnace charging raw materials and metallurgical coke and injection coal as fuels, and improving the production efficiency of blast furnace smelting by controlling lower adjusting parameters and a charging system. The adverse effect of titanium carbonitride on smooth blast furnace smelting is reduced, the blast furnace fuel structure is optimized, and carbon emission is reduced. Compared with the prior art, the blast furnace smelting method for the schreyerite with the high oxygen enrichment and the high pellet proportion, provided by the invention, adopts a specific improvement mode aiming at a specific blast furnace, raw materials and fuel, realizes relatively good overall interaction, and can improve the blast furnace smelting production efficiency of the vanadium titano-magnetite; the negative influence of titanium carbonitride on blast furnace smelting in the blast furnace smelting process is reduced, the blast furnace fuel structure is optimized, carbon emission is reduced, and the method can be applied and popularized in the blast furnace ironmaking field.

Description

Technical Field

[0001] The invention relates to the technical field of steel smelting, and more specifically to a blast furnace smelting method of high-oxygen-enriched and high-pellet ratio vanadium-titanium ore. Background Art

[0002] Vanadium-titanium magnetite is an important strategic resource in my country. The main application form at present is blast furnace smelting-converter vanadium extraction. In recent years, the titanium in the high TiO2 blast furnace slag formed by blast furnace smelting has been extracted and utilized by high-temperature carbonization + low-temperature chlorination. In the blast furnace smelting process of high-titanium vanadium-titanium magnetite, vanadium-titanium sinter + natural lump ore were the main raw materials before 2009. After 2009, vanadium-titanium pellets were used and became one of the main raw materials for blast furnaces, and the proportion of natural lump ore decreased. After unremitting efforts and the application of belt pellet roasting, the proportion of vanadium-titanium pellets entering the blast furnace of Panzhihua Iron and Steel in 2024 gradually increased and exceeded 50%. It is currently the only company in the world that has achieved high-pellet ratio blast furnace production and smelting of high-titanium vanadium-titanium magnetite. Compared with the production and smelting period with vanadium-titanium sinter as the main raw material, vanadium-titanium pellets as the main raw material have shown many advantages. Firstly, the quality of vanadium-titanium pellets is stable, the particle size is uniform, the return rate is low, the process energy consumption and processing cost are low; secondly, the TiO2 load entering the furnace is balanced under the premise of controlling the TiO2 content in blast furnace slag at a certain level. The vanadium-titanium magnetite concentrate originally used for sintering and agglomeration process is instead added to the blast furnace in the form of vanadium-titanium pellets, which provides conditions for the material structure adjustment and quality improvement of vanadium-titanium sintered ore. The TiO2 content in vanadium-titanium sintered ore is reduced, the overall strength is increased by 4 percentage points, and the return rate is reduced by 3~4 percentage points; thirdly, with the overall improvement in the quality of the main raw materials entering the furnace, the stability and smooth operation of the blast furnace is enhanced.

[0003] However, there are still some problems in the current blast furnace smelting of vanadium-titanium magnetite. The return rate of vanadium-titanium sinter is still higher than that of ordinary sinter, and there is still room for further optimization and energy conservation and emission reduction; TiO2 in blast furnace slag is easily reduced to form a large amount of titanium carbonitride with a melting point of more than 2950℃, which has an adverse effect on the fluidity and separation of slag iron and slag iron, and the permeability of the blast furnace; the structure of vanadium-titanium pellets is denser than that of vanadium-titanium sinter, and it is not easy for reducing gas to enter the pellets. The medium-temperature reduction degree of vanadium-titanium pellets is lower than that of vanadium-titanium sinter, and the requirements for improving the utilization rate of blast furnace gas are also higher; with the increase of the proportion of blast furnace pellets, the natural pile angle of the pellets is smaller overall, the rolling effect of the distribution process is stronger, the airflow in the center and edge of the blast furnace is significantly weakened, and some blast furnaces even have adhesion of the furnace wall.

[0004] Therefore, it is very important to explore a blast furnace smelting method to further give play to the advantages of high vanadium titanium pellet blast furnace smelting and eliminate or reduce the problems arising from high vanadium titanium pellet blast furnace smelting. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a method for blast furnace smelting of vanadium-titanium ore with high oxygen enrichment and high pellet ratio, which can further increase the proportion of vanadium-titanium pellet ore entering the furnace, reduce the amount of titanium carbonitride generated during blast furnace smelting of high-titanium vanadium-titanium magnetite, further improve the gas utilization efficiency, optimize the blast furnace fuel structure, and reduce the carbon emissions of the ironmaking process, which can be promoted and applied in the blast furnace ironmaking field.

[0006] The present invention provides a method for smelting vanadium-titanium ore in a blast furnace with high oxygen enrichment and high pellet ratio, comprising the following steps:

[0007] For smelting objects: 1200m 3 ~2500m 3 The blast furnace uses vanadium-titanium pellets and sintered ore as raw materials and metallurgical coke and pulverized coal as fuel for smelting. By controlling the lower adjustment parameters and charging system, the blast furnace smelting production efficiency is improved, the adverse effects of titanium carbonitride on the smooth operation of blast furnace smelting are reduced, the blast furnace fuel structure is optimized, and carbon emissions are reduced.

[0008] Preferably, the roof structure of the blast furnace is a bell-less chute distribution structure.

[0009] Preferably, the vanadium-titanium pellets have a furnace loading ratio of 60% to 70%, a TiO2 content of ≥9.50wt%, a basicity of R0≤0.85, and a compressive strength of ≥2000N / piece;

[0010] The feeding ratio of the sintered ore is 30%-40%, the basicity R0 is 1.80-2.60, the TiO2 content is ≤1.50wt%, the drum strength index is ≥76%, and the mass fraction of the particle size of the sintered ore entering the furnace <5mm is ≤2.0%.

[0011] Preferably, the sum of the charging ratio of the vanadium-titanium pellets and the charging ratio of the sintered ore is 100%; after smelting, the TiO2 content in the obtained blast furnace slag is 21.0%~24.0%, the slag binary basicity R2 is 1.03~1.15, the slag ternary basicity R3 is 1.38~1.45, and the Al2O3 content is ≤15.0%.

[0012] Preferably, the metallurgical coke is dry quenched coke, and the strength after reaction CSR is 63% to 68%, the ash content Ad≤13.80%, and the sulfur content St≤0.75%;

[0013] The particle size of the injected coal is -200 mesh, the proportion is ≥65%, the ash content Ad is ≤13.00%, and the volatile content is 11%~16%.

[0014] Preferably, the control lower adjustment parameters include:

[0015] By controlling the oxygen enrichment rate to 5.0%~10.0%, the coal injection ratio to 130kg / t~170kg / t, and the hot air temperature to 1200℃~1240℃, the theoretical combustion temperature before the tuyere is controlled between 2260~2300℃.

[0016] Preferably, when the oxygen enrichment rate is at the upper limit of the range and the coal injection ratio has reached the upper limit of the range, the coal injection ratio is maintained unchanged and the blast humidity is increased to control the theoretical combustion temperature; the specific reference range of the influence of the oxygen enrichment rate, the coal injection ratio, the wind temperature and the blast humidity on the theoretical combustion temperature is: when the oxygen enrichment rate is increased by 1%, the theoretical combustion temperature increases by 45.6°C; when the wind temperature increases by 1°C, the theoretical combustion temperature increases by 0.697°C; when the coal injection ratio increases by 1kg / t, the theoretical combustion temperature decreases by 1.52°C; when the blast humidity increases by 1g / m 3 , the theoretical combustion temperature is reduced by 4.95℃.

[0017] Preferably, the calculation relationship between the theoretical combustion temperature and the oxygen enrichment, coal injection amount, wind temperature, and blast humidity is:

[0018] T f =155.47+0.697T B – 5.324H B +3385.625V O2 -1818.404V coal ;

[0019] Where, wind temperature T B The unit is ℃, the blast humidity is H B The unit is g / m³, the ratio of oxygen enrichment to blast volume V O2 The unit is m³ / m³, the ratio of coal injection volume to blast volume V coal The unit is kg / m³.

[0020] Preferably, the charging system comprises:

[0021] 1) From the center of the blast furnace throat to the edge of the throat wall, the circular throat is divided into 11 equal-area circular rings, and the depth of the charging line is controlled to be 1.6m~2.2m. The charging angles of the chute correspond to the 11 equally divided circular rings from small to large, and the corresponding rear chute angles are between 0°~43°. Based on this, the chute charging is divided into 11 gears, the coke charging gear is between the 3rd and 10th gears, and the ore charging gear is between the 5th and 9th gears;

[0022] 2) Sintered ore and pelletized ore are discharged from the ore bin onto the conveyor belt, and then transported to the blast furnace top tank by the conveyor belt. The discharge method is sintered ore-pelletized ore to reduce the rolling of pelletized ore on the conveyor belt. The ore batch weight is controlled at 30t / batch to 60t / batch, and the coke batch weight is equal to the ore batch weight divided by the coke load. The coke load is controlled at 4.20~4.80. The larger the blast furnace volume, the larger the ore batch weight and coke batch weight. The ore batch weight is selected based on the average increase of the furnace throat material surface height by 0.50m~0.70m after the ore is distributed, and the coke load is determined according to the blast furnace's wind receiving capacity.

[0023] Preferably, the ore batch weight is controlled at 30t / batch to 60t / batch including:

[0024] When the ore batch weight is ≥48t / batch, the number of ore distribution gears is 5, and the number of coke distribution gears is 7. The corresponding ore distribution and coke distribution chute angles are the same under the same number of gears. The chute angle corresponding to the maximum coke distribution gear is 1°~2° larger than the chute angle corresponding to the maximum ore distribution gear, and the chute angle corresponding to the minimum coke distribution gear is 5°~7° smaller than the chute angle corresponding to the minimum ore distribution gear. Ore is distributed from the 9th gear to the 5th gear in sequence, and the ore distribution ratios under each distribution gear are 15.4wt%, 23.1wt%, 23.1wt%, 23.1wt%, and 15.4wt% respectively; coke is distributed from the 10th gear to the 4th gear in sequence, and the coke distribution ratios under each distribution gear are 23wt%~26wt%, 10wt%~13wt%, 10wt%~13wt%, 10wt%~13wt%, 10wt%~13wt%, 10wt%~13wt%, 23wt%~26wt% respectively.

[0025] When the ore batch weight is between 30t / batch and 48t / batch, the number of ore distribution gears is 4, and the number of coke distribution gears is 6. The corresponding ore distribution and coke distribution chute angles are the same under the same number of gears. The chute angle corresponding to the maximum coke distribution gear is 1°~2° larger than the corresponding chute angle of the maximum ore distribution gear, and the chute angle corresponding to the minimum coke distribution gear is 5°~7° smaller than the corresponding chute angle of the minimum ore distribution gear. Ore is distributed from the 9th gear to the 6th gear in sequence, and the ore distribution ratios at each distribution gear are 20wt%, 30wt%, 30wt%, and 20wt% respectively; coke is distributed from the 10th gear to the 5th gear in sequence, and the coke distribution ratios at each distribution gear are 25wt%~30wt%, 11wt%~15wt%, 11wt%~15wt%, 11wt%~15wt%, 11wt%~15wt%, 25wt%~30wt% respectively.

[0026] The present invention provides a blast furnace smelting method for high oxygen-enriched and high pellet ratio vanadium-titanium ore, comprising the following steps: for a smelting object of 1200m 3 ~2500m 3The blast furnace uses vanadium-titanium pellets and sintered ore as raw materials, and metallurgical coke and pulverized coal as fuel for smelting. By controlling the lower adjustment parameters and charging system, the blast furnace smelting production efficiency is improved, the adverse effects of titanium carbonitride on the blast furnace smelting are reduced, the blast furnace fuel structure is optimized, and carbon emissions are reduced. Compared with the prior art, the high-oxygen-enriched and high-pellet ratio vanadium-titanium ore blast furnace smelting method provided by the present invention adopts a specific improvement method for specific blast furnaces, raw materials and fuels to achieve overall good interaction, which can improve the blast furnace smelting production efficiency of vanadium-titanium magnetite, reduce the adverse effects of titanium carbonitride on the blast furnace smelting during the blast furnace generation and smelting process, optimize the blast furnace fuel structure, reduce carbon emissions, and can be promoted and applied in the field of blast furnace ironmaking. DETAILED DESCRIPTION

[0027] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] The present invention provides a method for smelting vanadium-titanium ore in a blast furnace with high oxygen enrichment and high pellet ratio, comprising the following steps:

[0029] For smelting objects: 1200m 3 ~2500m 3 The blast furnace uses vanadium-titanium pellets and sintered ore as raw materials and metallurgical coke and pulverized coal as fuel for smelting. By controlling the lower adjustment parameters and charging system, the blast furnace smelting production efficiency is improved, the adverse effects of titanium carbonitride on the smooth operation of blast furnace smelting are reduced, the blast furnace fuel structure is optimized, and carbon emissions are reduced.

[0030] The present invention provides a blast furnace smelting method for high oxygen-enriched and high pellet ratio vanadium-titanium ore, which is specifically aimed at smelting objects of 1200m 3 ~2500m 3 The blast furnace has a top structure without a bell chute for material distribution.

[0031] In the present invention, the high-oxygen-enriched and high-pellet ratio vanadium-titanium ore blast furnace smelting method uses vanadium-titanium pellets and sintered ore as furnace raw materials and uses metallurgical coke and pulverized coal as fuel for smelting.

[0032] In the present invention, for the smelting object, vanadium-titanium magnetite is used as the main raw material for the furnace, and the first main raw material is vanadium-titanium pellets; the furnace ratio of the vanadium-titanium pellets is preferably 60%-70%, the TiO2 content is preferably ≥9.50wt%, the basicity R0 (ratio of CaO mass fraction to SiO2 mass fraction) is preferably ≤0.85, and the compressive strength is preferably ≥2000N / piece. For the smelting object, the second main raw material is a sintered ore with a low TiO2 content; the furnace ratio of the sintered ore is preferably 30%-40%, the basicity R0 (ratio of CaO mass fraction to SiO2 mass fraction) is preferably 1.80-2.60, the TiO2 content is preferably ≤1.50wt%, the drum strength index is preferably ≥76%, and the mass fraction of the sintered ore with a particle size of <5mm is preferably ≤2.0%.

[0033] In the present invention, the main fuels for the smelting object are metallurgical coke and pulverized coal injection; the metallurgical coke is preferably dry quenched coke to ensure stable coke quality; the post-reaction strength CSR of the metallurgical coke is preferably 63%~68%, the ash content Ad is preferably ≤13.80%, and the sulfur content St is preferably ≤0.75%; the particle size of the pulverized coal injection is preferably -200 mesh ratio ≥65%, the ash content Ad is preferably ≤13.00%, and the volatile matter is preferably 11%~16%.

[0034] In the present invention, the sum of the charging ratio of the vanadium-titanium pellets and the charging ratio of the sintered ore is 100%; the vanadium-titanium pellets and the sintered ore must meet the following requirements at the same time when the charging ratios are matched: after smelting, considering the fuel consumption and the material composition in the fuel ash, the TiO2 content in the obtained blast furnace slag is preferably 21.0%~24.0%, the binary basicity R2 (ratio of CaO mass fraction to SiO2 mass fraction) of the slag is preferably 1.03~1.15, the ternary basicity R3 (w(CaO+MgO) / w(SiO2)) of the slag is preferably 1.38~1.45, and the Al2O3 content is ≤15.0%. Considering all the above-mentioned limiting conditions, the sintered ore batching structure is adjusted based on the composition and proportion of the vanadium-titanium pellets, so as to adjust the basicity R0, TiO2 content, etc. of the sintered ore within the limited composition range of the sintered ore, and smelt and obtain the blast furnace slag composition within the limited range.

[0035] The above-mentioned charge structure defined in the present invention has the following advantages: (1) the proportion of vanadium-titanium pellets is increased to within the scope of the present invention, and the TiO2 content of the sintered ore is reduced to less than 1.5%. Compared with the existing sintered ore with a TiO2 content of ≥3.0%, the perovskite phase that reduces the strength of the sintered ore is further reduced, and the calcium ferrite phase that can increase the strength is increased. The drum strength of the sintered ore is improved, the return rate is reduced, and the total amount of sintered ore processed will also be reduced, which is conducive to further reducing the energy consumption and carbon emissions of sintered ore agglomeration; (2) the vanadium-titanium pellets are increased, and the TiO2 content of the sintered ore is reduced. The molten dripping temperature of the pelletized ore will be 30°C to 50°C higher than that of the sintered ore. The structure of the pelletized ore itself is relatively dense. The sintered ore first melts to form a liquid phase, and then infiltrates and reacts from the outside to the inside after contacting the pelletized ore. The amount of titanium carbonitride, a high-melting-point substance, that is easily reduced to form in the sintered ore is reduced, and the amount of TiO2 brought in by the pellets is increased. However, compared with sintered ore, it is less likely to generate titanium carbonitride, a high-melting-point substance. Therefore, the adjustment of the charge structure of the present invention will be beneficial to reducing the amount of titanium carbonitride generated during the entire blast furnace charge descending process.

[0036] In the present invention, the following control is performed on the lower adjustment parameters of the smelting object; the control of the lower adjustment parameters preferably includes:

[0037] By controlling the oxygen enrichment rate to 5.0%~10.0%, the coal injection ratio to 130kg / t~170kg / t, and the hot air temperature to 1200℃~1240℃, the theoretical combustion temperature before the tuyere is controlled between 2260~2300℃.

[0038] The present invention controls the theoretical combustion temperature before the tuyere between 2260 and 2300°C by comprehensive adjustment of the oxygen enrichment rate, the coal injection ratio, the wind temperature and the blast humidity; when the oxygen enrichment rate is at the upper limit of the range and the coal injection ratio has reached the upper limit of the range, the coal injection ratio is maintained unchanged and the blast humidity is increased to control the theoretical combustion temperature; the specific reference of the influence of the oxygen enrichment rate, the coal injection ratio, the wind temperature and the blast humidity on the theoretical combustion temperature is: when the oxygen enrichment rate is increased by 1%, the theoretical combustion temperature is increased by 45.6°C; when the wind temperature is increased by 1°C, the theoretical combustion temperature is increased by 0.697°C; when the coal injection ratio is increased by 1kg / t, the theoretical combustion temperature is reduced by 1.52°C; when the blast humidity is increased by 1g / m 3 , the theoretical combustion temperature is reduced by 4.95℃.

[0039] In the present invention, the calculation relationship between the theoretical combustion temperature and the oxygen enrichment, coal injection amount, wind temperature, and blast humidity is preferably:

[0040] T f =155.47+0.697T B – 5.324H B +3385.625V O2 -1818.404V coal ;

[0041] Where, wind temperature T B The unit is ℃, the blast humidity is H B The unit is g / m³, the ratio of oxygen enrichment to blast volume V O2 The unit is m³ / m³, the ratio of coal injection volume to blast volume V coal The unit is kg / m³.

[0042] The benefits of the lower adjustment method of the present invention are: (1) the higher oxygen enrichment rate allows the hot air to undergo an incomplete combustion reaction before the tuyere to form high-temperature coal gas with a higher CO concentration, thereby increasing the indirect reduction rate of CO to iron oxides, compensating for the adverse effect of the relatively dense structure of vanadium-titanium pellets on coal gas utilization, thereby improving the overall utilization rate of coal gas; (2) the higher oxygen enrichment rate increases the combustion rate of the injected coal powder before the tuyere, allowing the blast furnace to accept a larger amount of coal injection, and also increases the concentration of CO in the coal gas; at the same time, it also increases the amount of coal gas generated in the furnace, so that the amount of coal gas in the center and edge of the blast furnace is increased, which can effectively reduce the degree of weakening of the airflow in the center and edge of the blast furnace, and is more conducive to the stable and smooth operation of the blast furnace; the rapid combustion of coal powder also reduces the amount of unburned coal powder in the furnace, thereby reducing the reduction of slag TiO2 by unburned coal powder; (3) the higher Under the oxygen enrichment rate, in order to control the appropriate theoretical combustion temperature, it is necessary to increase the blast humidity. Water vapor reacts with water gas in front of the tuyere to generate hydrogen. Compared with CO molecules, hydrogen has smaller molecules and stronger permeability. At high temperatures, its ability to reduce iron oxides is stronger than CO. Therefore, increasing the blast humidity is more conducive to improving the comprehensive utilization rate of coal gas; (4) More importantly, a higher oxygen enrichment rate increases the blast furnace reaction rate, shortens the smelting cycle of the charge in the blast furnace, and reduces the residence time of titanium-containing charge and titanium-containing slag in the blast furnace, that is, shortens the time for TiO2 to be directly reduced to generate high-melting-point titanium carbonitride, which is beneficial to reducing the amount of titanium carbonitride generated; at the same time, a higher oxygen enrichment rate can increase the local oxygen potential in the furnace area, prompting the titanium carbonitride generated in the soft melt dripping zone above the tuyere to be secondary oxidized into titanium oxide, which also reduces the amount of titanium carbonitride.

[0043] In the present invention, the charging system of the smelting object is controlled as follows; the charging system preferably includes:

[0044] 1) From the center of the blast furnace throat to the edge of the throat wall, the circular throat is divided into 11 equal-area circular rings, and the depth of the charging line is controlled to be 1.6m~2.2m. The charging angles of the chute correspond to the 11 equally divided circular rings from small to large, and the corresponding rear chute angles are between 0°~43°. Based on this, the chute charging is divided into 11 gears, the coke charging gear is between the 3rd and 10th gears, and the ore charging gear is between the 5th and 9th gears;

[0045] 2) Sintered ore and pelletized ore are discharged from the ore bin onto the conveyor belt, and then transported to the blast furnace top material tank by the conveyor belt. The discharge method is sintered ore-pelletized ore to reduce the rolling of the pelletized ore on the conveyor belt. The ore batch weight is controlled at 30t / batch to 60t / batch, and the coke batch weight is equal to the ore batch weight divided by the coke load. The coke load is controlled at 4.20~4.80. The larger the blast furnace volume, the larger the ore batch weight and coke batch weight. The ore batch weight is selected based on the average increase of the furnace throat material surface height by 0.50m~0.70m after the ore is distributed, and the coke load is determined according to the wind resistance of the blast furnace.

[0046] In the present invention, the ore batch weight is controlled at 30t / batch to 60t / batch and preferably includes:

[0047] When the ore batch weight is ≥48t / batch, the number of ore distribution gears is 5, and the number of coke distribution gears is 7. The corresponding chute angles of ore distribution and coke distribution are the same under the same number of gears. The chute angle corresponding to the maximum coke distribution gear is 1°~2° larger than the chute angle corresponding to the maximum ore distribution gear, and the chute angle corresponding to the minimum coke distribution gear is 5°~7° smaller than the chute angle corresponding to the minimum ore distribution gear. Ore is distributed from the 9th gear to the 5th gear in sequence, and the ore distribution ratio (mass fraction) under each distribution gear is The coking ratios (mass fractions) at each gear position are 23wt%~26wt%, 10wt%~13wt%, 10wt%~13wt%, 10wt%~13wt%, 10wt%~13wt%, 10wt%~13wt%, 10wt%~13wt%, 23wt%~26wt% respectively.

[0048] When the ore batch weight is between 30t / batch and 48t / batch, the number of ore distribution gears is 4, and the number of coke distribution gears is 6. The corresponding ore distribution and coke distribution chute angles are the same under the same number of gears. The chute angle corresponding to the maximum coke distribution gear is 1°~2° larger than the corresponding chute angle of the maximum ore distribution gear, and the chute angle corresponding to the minimum coke distribution gear is 5°~7° smaller than the corresponding chute angle of the minimum ore distribution gear. Ore is distributed from the 9th gear to the 6th gear in sequence, and the ore distribution ratio (mass fraction) at each distribution gear is 20wt%, 30wt%, 30wt%, and 20wt%, respectively; coke is distributed from the 10th gear to the 5th gear in sequence, and the coke distribution ratio (mass fraction) at each distribution gear is 25wt%~30wt%, 11wt%~15wt%, 11wt%~15wt%, 11wt%~15wt%, 11wt%~15wt%, 25wt%~30wt%, respectively.

[0049] The above-mentioned charging system of the present invention is beneficial in that: (1) when the ore bin is loaded to the blast furnace top bin via the belt, the sintered ore with a large natural heap angle is located at the bottom, which can effectively reduce the rolling effect of the pelletized ore with a small natural heap angle on the belt; (2) the number of intermediate distribution gears corresponds to a large distribution specific gravity of ore and a small distribution specific gravity of coke, but the maximum and minimum distribution gears correspond to a small distribution specific gravity of ore and a large distribution specific gravity of coke, which is conducive to the formation of coke pile tips near the edge and center of the furnace throat during the distribution process, reducing the amount of rolling of ore toward the edge and center of the furnace throat, ensuring good air permeability of the edge and center of the blast furnace, forming two airflows at the edge and center of the blast furnace in the blast furnace, and ensuring stable and smooth operation of the blast furnace; at the same time, the actual ore and coke ratio of the intermediate ring belt is large, which is conducive to suppressing the airflow and improving the gas utilization rate; (3) The charging system matches the larger furnace belly gas volume of the lower adjustment system, maintaining two furnace airflow channels at the center and edge for the blast furnace gas, and ensuring that the blast furnace can run stably and smoothly.

[0050] The present invention provides a blast furnace smelting method for high oxygen-enriched and high pellet ratio vanadium-titanium ore, comprising the following steps: for a smelting object of 1200m 3 ~2500m 3 The blast furnace uses vanadium-titanium pellets and sintered ore as raw materials, and metallurgical coke and pulverized coal as fuel for smelting. By controlling the lower adjustment parameters and charging system, the blast furnace smelting production efficiency is improved, the adverse effects of titanium carbonitride on the blast furnace smelting are reduced, the blast furnace fuel structure is optimized, and carbon emissions are reduced. Compared with the prior art, the high-oxygen-enriched and high-pellet ratio vanadium-titanium ore blast furnace smelting method provided by the present invention adopts a specific improvement method for specific blast furnaces, raw materials and fuels to achieve overall good interaction, which can improve the blast furnace smelting production efficiency of vanadium-titanium magnetite, reduce the adverse effects of titanium carbonitride on the blast furnace smelting during the blast furnace generation and smelting process, optimize the blast furnace fuel structure, reduce carbon emissions, and can be promoted and applied in the field of blast furnace ironmaking.

[0051] In order to further illustrate the present invention, the following examples are provided for detailed description.

[0052] Example 1

[0053] Blast furnace A, which uses vanadium-titanium magnetite as its main raw material, carried out a 15-day industrial test before shutting down for maintenance. The test was divided into two phases, each lasting six days, with a transition period of three days in between. During the test period, the quality of coke and PCI was kept good and stable, as in the baseline period. The specific quality control is shown in Table 1.

[0054] Table 1 Fuel indicators during industrial experiment (%)

[0055]

[0056] During the experiment, the pellet ratio was increased from 53% to 60% and 66% respectively. During the experiment, the sintering ore batching structure was changed on the basis of the baseline period, and the TiO2 content of the sintering ore was reduced from 3.50% in the baseline period to 1.24% and 1.21%, and the drum index of the sintering ore was increased from 76% to 78.5%. The strength was improved. In order to balance the binary basicity R2 of the slag, the basicity R0 of the sintering ore was gradually increased from 2.03 to 2.28 and 2.60. With the changes in raw material composition and charge structure, the blast furnace slag stabilized the binary basicity R2 at 1.09 and the ternary basicity R3 between 1.38 and 1.45, and the TiO2 content of the slag was appropriately increased to 23.50%. During the test, the oxygen enrichment rate was increased from 4.3% to 6.0% and 8.0% respectively, and the coal injection ratio was increased from 145kg / t to 155kg / t and 170kg / t respectively. In order to stably control the theoretical combustion temperature between 2290℃ and 2300℃, the blast humidity was increased from 16g / m³ to 29g / m³ and 41g / m³ respectively. In terms of charging system, since the bulk density of pellets is greater than that of sintered ore, the ore batch weight is appropriately reduced from 44.5t / batch to 46t / batch, the coke load is increased from 4.4t / t to 4.6t / t, the material line depth is kept unchanged, the maximum ore distribution ratio is reduced from 27.3% to 20%, and the middle ore distribution ratio is increased from 27.3% to 30%; at the same time, the sum of the coke ratios of the minimum coke distribution ratio and the second small coke distribution ratio is maintained between 37.0% and 40% as a whole, and the sum of the coke ratios of the maximum coke distribution ratio and the second largest coke distribution ratio is appropriately increased to ensure that under high oxygen enrichment adjustment, after the furnace gas volume increases, the edge gas flow has a smooth gas path. See Tables 2 to 4 for details.

[0057] Table 2 Charge structure and main components of raw materials during industrial experiments

[0058]

[0059] Table 3 Some technical indicators and slag composition of blast furnace during industrial experiment

[0060]

[0061] Table 4 Blast furnace charging system during industrial experiment

[0062]

[0063] The experimental results show that under the above-mentioned operation adjustments, the blast furnace indicators are significantly improved. The blast furnace utilization coefficient is increased from 2.74t / (m³·d) to 2.93t / (m³·d) and 3.13t / (m³·d), the gas utilization rate is increased from 44.4% to 45.2% and 45.8%, the overall fuel ratio is reduced from 545kg / t to 542kg / t, and the coke ratio is reduced from 400kg / t to 388kg / t and 376kg / t, which greatly improves the blast furnace fuel structure.

[0064] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for smelting vanadium-titanium ore in a blast furnace with high oxygen enrichment and high pellet ratio, comprising the following steps: For smelting objects: 1200m 3 ~2500m 3 The blast furnace uses vanadium-titanium pellets and sintered ore as raw materials and metallurgical coke and pulverized coal as fuel for smelting. By controlling the lower adjustment parameters and charging system, the blast furnace smelting production efficiency is improved, the adverse effects of titanium carbonitride on the smooth operation of blast furnace smelting are reduced, the blast furnace fuel structure is optimized, and carbon emissions are reduced.

2. The method for smelting vanadium-titanium ore in a blast furnace with high oxygen enrichment and high pellet ratio according to claim 1, characterized in that: The roof structure of the blast furnace is bell-less chute distribution.

3. The method for smelting vanadium-titanium ore in a blast furnace with high oxygen enrichment and high pellet ratio according to claim 1, characterized in that: The vanadium-titanium pellets have a furnace loading ratio of 60% to 70%, a TiO2 content of ≥9.50wt%, a basicity of R0≤0.85, and a compressive strength of ≥2000N / piece; The feeding ratio of the sintered ore is 30%-40%, the basicity R0 is 1.80-2.60, the TiO2 content is ≤1.50wt%, the drum strength index is ≥76%, and the mass fraction of the particle size of the sintered ore entering the furnace <5mm is ≤2.0%.

4. The method for smelting vanadium-titanium ore in a blast furnace with high oxygen enrichment and high pellet ratio according to claim 3, characterized in that: The sum of the charging ratio of the vanadium-titanium pellets and the charging ratio of the sintered ore is 100%; after smelting, the TiO2 content in the obtained blast furnace slag is 21.0%~24.0%, the slag binary basicity R2 is 1.03~1.15, the slag ternary basicity R3 is 1.38~1.45, and the Al2O3 content is ≤15.0%.

5. The method for smelting vanadium-titanium ore in a blast furnace with high oxygen enrichment and high pellet ratio according to claim 1, characterized in that: The metallurgical coke is dry quenched coke, and the strength after reaction CSR is 63% to 68%, the ash content Ad≤13.80%, and the sulfur content St≤0.75%; The particle size of the injected coal is -200 mesh, the proportion is ≥65%, the ash content Ad is ≤13.00%, and the volatile content is 11%~16%.

6. The method for smelting vanadium-titanium ore in a blast furnace with high oxygen enrichment and high pellet ratio according to claim 1, characterized in that: The control lower adjustment parameters include: By controlling the oxygen enrichment rate to 5.0%~10.0%, the coal injection ratio to 130kg / t~170kg / t, and the hot air temperature to 1200℃~1240℃, the theoretical combustion temperature before the tuyere is controlled between 2260~2300℃.

7. The method for smelting vanadium-titanium ore in a blast furnace with high oxygen enrichment and high pellet ratio according to claim 6, characterized in that: When the oxygen enrichment rate is at the upper limit of the range and the coal injection ratio has reached the upper limit of the range, the coal injection ratio is maintained unchanged and the blast humidity is increased to control the theoretical combustion temperature; the specific reference for the control range of the influence of oxygen enrichment rate, coal injection ratio, wind temperature and blast humidity on the theoretical combustion temperature is: when the oxygen enrichment rate increases by 1%, the theoretical combustion temperature increases by 45.6℃; when the wind temperature increases by 1℃, the theoretical combustion temperature increases by 0.697℃; when the coal injection ratio increases by 1kg / t, the theoretical combustion temperature decreases by 1.52℃; when the blast humidity increases by 1g / m 3 , the theoretical combustion temperature is reduced by 4.95℃.

8. The method for smelting vanadium-titanium ore in a blast furnace with high oxygen enrichment and high pellet ratio according to claim 7, characterized in that: The calculation relationship between the theoretical combustion temperature and the oxygen enrichment, coal injection amount, wind temperature, and blast humidity is: T f =155.47+0.697T B – 5.324H B +3385.625V O2 -1818.404V coal ; Where, wind temperature T B The unit is ℃, the blast humidity is H B The unit is g / m³, the ratio of oxygen enrichment to blast volume V O2 The unit is m³ / m³, the ratio of coal injection volume to blast volume V coal The unit is kg / m³.

9. The method for smelting vanadium-titanium ore in a blast furnace with high oxygen enrichment and high pellet ratio according to claim 1, characterized in that: The charging system includes: 1) From the center of the blast furnace throat to the edge of the throat wall, the circular throat is divided into 11 equal-area circular rings, and the depth of the charging line is controlled to be 1.6m~2.2m. The charging angles of the chute correspond to the 11 equally divided circular rings from small to large, and the corresponding rear chute angles are between 0°~43°. Based on this, the chute charging is divided into 11 gears, the coke charging gear is between the 3rd and 10th gears, and the ore charging gear is between the 5th and 9th gears; 2) Sintered ore and pelletized ore are discharged from the ore bin onto the conveyor belt, and then transported to the blast furnace top material tank by the conveyor belt. The discharge method is sintered ore-pelletized ore to reduce the rolling of the pelletized ore on the conveyor belt. The ore batch weight is controlled at 30t / batch to 60t / batch, and the coke batch weight is equal to the ore batch weight divided by the coke load. The coke load is controlled at 4.20~4.

80. The larger the blast furnace volume, the larger the ore batch weight and coke batch weight. The ore batch weight is selected based on the average increase of the furnace throat material surface height by 0.50m~0.70m after the ore is distributed, and the coke load is determined according to the wind resistance of the blast furnace.

10. The method for smelting vanadium-titanium ore in a blast furnace with high oxygen enrichment and high pellet ratio according to claim 9, characterized in that: The ore batch weight is controlled at 30t / batch to 60t / batch including: When the ore batch weight is ≥48t / batch, the number of ore distribution gears is 5, and the number of coke distribution gears is 7. The corresponding ore distribution and coke distribution chute angles are the same under the same number of gears. The chute angle corresponding to the maximum coke distribution gear is 1°~2° larger than the chute angle corresponding to the maximum ore distribution gear, and the chute angle corresponding to the minimum coke distribution gear is 5°~7° smaller than the chute angle corresponding to the minimum ore distribution gear. Ore is distributed from the 9th gear to the 5th gear in sequence, and the ore distribution ratios under each distribution gear are 15.4wt%, 23.1wt%, 23.1wt%, 23.1wt%, and 15.4wt% respectively; coke is distributed from the 10th gear to the 4th gear in sequence, and the coke distribution ratios under each distribution gear are 23wt%~26wt%, 10wt%~13wt%, 10wt%~13wt%, 10wt%~13wt%, 10wt%~13wt%, 10wt%~13wt%, 23wt%~26wt% respectively. When the ore batch weight is between 30t / batch and 48t / batch, the number of ore distribution gears is 4, and the number of coke distribution gears is 6. The corresponding ore distribution and coke distribution chute angles are the same under the same number of gears. The chute angle corresponding to the maximum coke distribution gear is 1°~2° larger than the corresponding chute angle of the maximum ore distribution gear, and the chute angle corresponding to the minimum coke distribution gear is 5°~7° smaller than the corresponding chute angle of the minimum ore distribution gear. Ore is distributed from the 9th gear to the 6th gear in sequence, and the ore distribution ratios at each distribution gear are 20wt%, 30wt%, 30wt%, and 20wt% respectively; coke is distributed from the 10th gear to the 5th gear in sequence, and the coke distribution ratios at each distribution gear are 25wt%~30wt%, 11wt%~15wt%, 11wt%~15wt%, 11wt%~15wt%, 11wt%~15wt%, 25wt%~30wt% respectively.

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