A method for smelting high-proportion vanadium-titanium iron ore in an oxygen blast furnace

Abstract

The present invention discloses a method for smelting high-proportion vanadium-titanium iron ore in an oxygen blast furnace, comprising the following steps: the blast furnace is injected with pure oxygen, pure oxygen, hot coal gas, and pulverized coal are sprayed into the tuyere, iron material and coke are added from the furnace top, wherein the volume percentage of nitrogen in the top gas is less than 25%, and the top gas is recycled after removing carbon dioxide. The method for smelting high-proportion vanadium-titanium iron ore in an oxygen blast furnace of the present invention can achieve a blast furnace vanadium-titanium iron ore ratio greater than 60%, a TiO2 mass fraction in the blast furnace slag greater than 15% and less than 45%, and a reduction of carbon dioxide emissions by more than 30%. This method solves the problems of increasing the proportion of vanadium-titanium iron ore in existing blast furnace smelting, such as slag viscosity, difficulty in separating slag and iron, poor furnace conditions, high costs, and high carbon emissions. This method thus improves the utilization efficiency of vanadium and titanium resources and reduces smelting costs and carbon emissions.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgy, and in particular to a method for smelting high-proportion vanadium-titanium iron ore in an oxygen blast furnace. Background Art

[0002] Currently, the most technologically mature ironmaking processes include blast furnace ironmaking, smelting reduction (HIsmelt, COREX, Finex), direct reduction (gas-based direct reduction, coal-based direct reduction), etc. However, each of these processes has its own advantages and disadvantages, mainly:

[0003] (1) Blast furnace ironmaking process: The technology is mature and can achieve an annual production capacity of more than one million tons per unit. However, its disadvantages are excessive reliance on high-quality metallurgical coke and the need to build supporting coking, sintering, and pelletizing facilities, resulting in large system investments. Blast furnace operation is difficult, and recovery after abnormal furnace conditions and fluctuations is difficult. Costs, carbon emissions, and energy consumption are high. At the same time, the N2 content in traditional blast furnaces accounts for more than 40% of the total gas phase, which easily generates Ti(C,N), forming foamy slag in the furnace, which is not conducive to smooth production and indicator optimization.

[0004] (2) Melting reduction: ① The heat transfer effect of the HIsmelt process is poor, the molten iron temperature in the molten pool is low, only 1400℃-1450℃, and the flue gas volume is as high as 2700Nm 3 1. The temperature of the iron and flue gas reaches 1600°C, and a large amount of physical heat is lost outside the furnace with the flue gas, resulting in high iron loss, high fuel consumption, and high carbon emissions. 2. The [Si] content of COREX and Finex hot metal is high, resulting in excessive gas generation and high primary carbon consumption. 3. The chemical energy utilization rate of carbon is insufficient, and some carbon escapes with the gas in the form of CO, preventing further utilization of its chemical energy.

[0005] (3) Direct reduction: ① Hydrogen-based vertical furnaces have high requirements for ore quality; ② Coal-based direct reduction requires solid fuel, so the carbon consumption is high, and the same problem exists as gas-based vertical furnaces in that they have high requirements for ore quality.

[0006] Vanadium-titanium magnetite is a complex ore containing multiple metallic elements, primarily iron, vanadium, and titanium. It is the world's primary raw material for vanadium production and the primary mineral source for refining titanium and iron. It is also recognized as one of the most difficult minerals to smelt, making its comprehensive utilization challenging.

[0007] At present, the main smelting process of vanadium-titanium iron ore is blast furnace smelting. There are two technical difficulties in blast furnace smelting of vanadium-titanium iron ore:

[0008] First, the proportion of vanadium-titanium ore is difficult to increase. In the prior art, when the proportion of vanadium-titanium iron ore in the blast furnace (the vanadium-titanium iron ore proportion in the blast furnace referred to in the present invention refers to the ratio of the amount of vanadium-titanium iron ore in the iron-containing raw materials used to produce sintered ore and pellets to the sum of the total amount of iron-containing raw materials used to produce sintered ore and pellets and the amount of iron-containing lump ore used in the blast furnace) increases, the blast furnace slag (TiO2) content increases, Ti(C,N), TiC, and TiN are generated, resulting in slag viscosity, difficulty in separating slag and iron, and foamy slag. At the same time, if the proportion of vanadium-titanium iron ore in the blast furnace is increased by increasing the proportion of vanadium-titanium iron ore in the sintering raw materials, then as the (TiO2) content in the sintered ore increases, it will cause a series of technical problems such as reduced sinter drum strength, increased reduction pulverization, poor blast furnace operation, abnormal furnace conditions, increased sintering return rate, and increased fuel cost per ton of iron.

[0009] Second, the process has high carbon emissions and energy consumption. CO accounts for approximately 20-30% of blast furnace top gas. Existing technologies fail to effectively utilize the chemical energy of this CO, instead using combustion to generate electricity. The thermal energy conversion efficiency of blast furnace gas combustion for power generation is less than 40%, resulting in high system energy consumption and carbon emissions. Summary of the Invention

[0010] The purpose of the present invention is to provide a method for smelting high-proportion vanadium-titanium iron ore in an oxygen blast furnace, which is used to solve the technical problems in the existing technology of blast furnace smelting of vanadium-titanium iron ore, such as difficulty in increasing the proportion of vanadium-titanium iron ore, high carbon emissions and high cost.

[0011] To achieve the above object, an embodiment of the present invention provides a method for smelting high-proportion vanadium-titanium iron ore in an oxygen blast furnace, comprising the following steps:

[0012] The blast furnace uses pure oxygen injection, with pure oxygen, hot coal gas and pulverized coal injected into the tuyere; iron and coke are added from the top of the furnace; the volume percentage of nitrogen in the top gas is less than 25%; the top gas is recycled after CO2 is removed;

[0013] The iron material is pelletized ore or the iron material is pelletized ore and at least one of the following materials: sintered ore and lump ore;

[0014] The TiO2 content in pellets is 3%-13%. The iron raw material used to produce pellets is vanadium-titanium iron ore. The proportion of pellets in the iron feed of the blast furnace is greater than 30%. The TiO2 content in sintered ore is less than 5%.

[0015] The mass fraction of TiO2 in the blast furnace slag generated by smelting is greater than 15% and less than 45%, the proportion of vanadium-titanium iron ore in the blast furnace is greater than 60%, and the CO2 emission of the blast furnace is reduced by 30%.

[0016] In one preferred embodiment of the present invention, the hot gas is the gas heated by the gas heating furnace. The gas sources in the gas heating furnace include coke oven gas, water vapor and purified gas. The flow rate of the coke oven gas fed into the gas heating furnace is 20Nm 3 / t-200Nm 3 / t, the ratio of water vapor to coke oven gas fed into the heating furnace is 0.10-0.30:1.

[0017] One of the preferred solutions of the present invention is that during the blast furnace smelting process,

[0018] When the mass fraction of TiO2 in blast furnace slag is greater than 15% and less than or equal to 18%, the sum of the mass fractions of [Si] and [Ti] in molten iron is greater than or equal to 0.4% and less than or equal to 0.8%;

[0019] When the mass fraction of TiO2 in blast furnace slag is greater than 18% and less than or equal to 20%, the sum of the mass fractions of [Si] and [Ti] in molten iron is greater than or equal to 0.3% and less than or equal to 0.7%;

[0020] When the mass fraction of TiO2 in blast furnace slag is greater than 20% and less than or equal to 25%, the sum of the mass fractions of [Si] and [Ti] in molten iron is greater than or equal to 0.10% and less than or equal to 0.6%;

[0021] When the mass fraction of TiO2 in blast furnace slag is greater than 25%, the sum of the mass fractions of [Si] and [Ti] in molten iron is ≥0.05% and ≤0.55%.

[0022] In one preferred embodiment of the present invention, the mass ratio of blast furnace iron to coke is 5.5-7.5:1, and the mass ratio of blast furnace iron to coal powder is 15-40:1; in blast furnace smelting, the blast furnace fuel ratio is less than 400 kg / t, and the coke ratio is less than 300 kg / t.

[0023] In one of the preferred solutions of the present invention, the distribution coefficient of vanadium element in molten iron and slag during blast furnace smelting is [V] / (V2O5)>1.1.

[0024] In one of the preferred solutions of the present invention, the flow rate of the hot gas injected is 700Nm 3 / t-1280Nm 3 / t, the flow rate of pure oxygen injected is 145Nm 3 / t-245Nm 3 / t.

[0025] One of the preferred solutions of the present invention is a method for charging iron and coke as follows: at the height of the blast furnace charge surface, take a horizontal cross-section of the blast furnace, divide the circle where the cross-section is located into 11 equal-area rings, and number them in sequence from the inner ring to the outer ring. The charging system is: 60%-80% of the coke is distributed in rings 9-11 and rings 1-5, 20%-40% of the coke is distributed in rings 6-8, 70%-90% of the iron is distributed in rings 4-10, and 10%-30% of the iron is distributed in rings 1-3 and 11.

[0026] In summary, the beneficial effects of the present invention are:

[0027] 1. Solve the problem of sticky and foamy slag in vanadium-titanium iron ore smelting. The volume percentage of N2 in the top gas in the smelting method of the present invention is less than 25%, which is significantly lower than the 45%-60% volume percentage of N2 in traditional blast furnace gas. Compared with traditional blast furnaces, the smelting process of the present invention reduces the N2 partial pressure, increases the CO partial pressure, and rationally controls the furnace temperature, all of which effectively inhibit the formation of Ti(C,N). This prevents the slag from becoming sticky and difficult to separate from the iron and slag, controls the foamy slag, and thus solves one of the problems that affect the increase in the proportion of vanadium-titanium iron ore in blast furnaces.

[0028] 2. Solve the problem of poor metallurgical properties of vanadium-titanium sinter. By optimizing the ore blending structure, controlling the TiO2 content in the sintered ore to less than 5%, and adding as much vanadium-titanium iron ore as possible to the pelletizing mix, this invention solves a series of technical problems caused by reduced drum strength, high reduction pulverization, and high ore return rate of vanadium-titanium sintered ore, which lead to poor blast furnace operation, poor furnace conditions, and increased fuel costs per ton of iron sintered. This further solves another problem that affects the increase in the proportion of vanadium-titanium iron ore in blast furnaces.

[0029] 3. The present invention significantly reduces ore blending costs. By optimizing the ore blending structure, the present invention achieves a 60%-100% vanadium-titanium iron ore ratio and a comprehensive raw material titanium load of 110-220 kg / t. The average price difference between domestic vanadium-titanium iron ore and ordinary iron ore is 200 yuan / ton. Based on a conservative calculation of a 60% vanadium-titanium iron ore ratio and a molten iron consumption of 1.6 tons / ton, the ore blending cost can be reduced by 192 yuan per ton of molten iron.

[0030] 4. The present invention significantly increases the TiO2 mass percentage in the slag. In conventional blast furnace smelting of vanadium-titanium iron ore, when the TiO2 mass percentage in the vanadium-titanium iron ore is less than 12%, the TiO2 mass percentage in the blast furnace slag is less than 23%. The present invention can achieve a TiO2 mass percentage in the blast furnace slag within the range of 15-45%. Specifically, when the TiO2 mass percentage in the vanadium-titanium iron ore reaches 8%, the TiO2 mass percentage in the blast furnace slag can reach 27%; when the TiO2 mass percentage in the vanadium-titanium iron ore reaches 10%, the TiO2 mass percentage in the blast furnace slag can reach 30%; and when the TiO2 mass percentage in the vanadium-titanium iron ore is greater than 12%, the TiO2 mass percentage in the blast furnace slag can reach 40%. The increase in the TiO2 mass percentage in the blast furnace slag significantly increases the utilization value of the slag.

[0031] 5. Reduced blast furnace fuel costs and CO2 emissions. This invention uses pure oxygen injection, removes CO2 from the top gas, heats it, and sprays it back into the furnace. This increases the amount of reducing gas (CO) in the furnace and reduces the amount of solid fuel required to burn in the tuyere (the purpose of burning solid fuel in the tuyere is to provide heat and CO reducing gas). This reduces solid fuel consumption by 30-40%, and reduces the combined fuel and power costs by approximately 50-100 yuan per ton of molten iron (prices vary in different regions, resulting in different cost reduction figures). BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a smelting process flow chart of an embodiment of the present invention.

[0033] Among them, 1-blast furnace, 2-gas purification facilities, 3-gas pipeline network, 4-gas heating furnace. DETAILED DESCRIPTION

[0034] The present invention provides a method for smelting high-proportion vanadium-titanium iron ore in an oxygen blast furnace. The device involved includes a blast furnace 1, a gas purification facility 2 and a gas heating furnace 4. The smelting method includes the following steps: adding blast furnace iron and coke into the blast furnace 1, using pure oxygen injection in the blast furnace 1, spraying pure oxygen, hot coal gas and coal powder at the tuyere for smelting, smelting to generate liquid slag and molten iron, and discharging the slag and molten iron out of the furnace through the slag and iron outlet.

[0035] The specific process flow and process parameters are as follows:

[0036] (1) Process flow

[0037] like Figure 1 As shown in the figure, the process flow of smelting high-proportion vanadium-titanium iron ore in an oxygen blast furnace is:

[0038] ① The hot coal gas is blown into the blast furnace 1 through the direct blowing pipe of the air supply branch pipe, and then through the large, second, and small tuyere sleeves in sequence; the pulverized coal is injected through the coal injection gun located in the direct blowing pipe of the air supply branch pipe, and the coal injected by the coal injection gun is blown into the blast furnace 1 through the large, second, and small tuyere sleeves in sequence; oxygen is blown into the blast furnace 1 through the small tuyere sleeve;

[0039] ② Blast furnace coke and iron material are loaded into the furnace from the top of the blast furnace through the charging equipment, wherein the iron material is pelletized ore or the iron material is pelletized ore and at least one of the following materials: sintered ore and lump ore; blast furnace fuel includes but is not limited to pulverized coal and coke;

[0040] ③ The gas generated by the combustion of oxygen and fuel in front of the tuyere, the hot gas injected from the tuyere sleeve, and the gas generated by the chemical reaction in the furnace together form the bosh gas. During the upward process of the bosh gas, it undergoes physical and chemical reactions with the descending iron material to produce liquid slag and molten iron, which are discharged from the slag and iron outlet.

[0041] ④ The top gas generated by the furnace reaction is discharged through the top gas pipeline. After being dedusted, CO2-free, and H2O-free by gas purification facility 2, it becomes purified gas. This purified gas then reaches gas pipeline network 3. Part of this purified gas is transmitted to other users for use, while the remaining part is mixed with coke oven gas and water vapor and transported to gas heating furnace 4, where it is heated to become hot gas. This entire smelting process achieves a carbon cycle.

[0042] (2) Material structure and slag making system

[0043] Due to the poor sintering characteristics of vanadium-titanium iron ore, the quality of the sintered ore prepared from it is poor, which is mainly manifested in low drop strength, low drum strength, low yield and severe low-temperature reduction pulverization. Therefore, the industrial application of vanadium-titanium iron ore is limited. When the proportion of vanadium-titanium iron ore in the sintered ore is too large, it will cause a series of problems such as high blast furnace return rate, increased fuel cost per ton of iron, poor blast furnace permeability and poor furnace conditions. In order to increase the proportion of vanadium-titanium iron ore entering the blast furnace while controlling costs and stabilizing furnace conditions, the present invention preferentially adds vanadium-titanium iron ore to the pelletizing ingredients, and adds a small amount of the surplus to the sintering ingredients, and controls the TiO2 content in the sintered ore to less than 5%. Specifically:

[0044] ① In the pelletizing process, the proportion of vanadium-titanium iron ore in the iron material is selected to be the maximum, for example, 100% vanadium-titanium iron ore is used for pelletizing, and no other iron materials other than vanadium-titanium iron ore are added. The TiO2 content in the pellet is determined by the TiO2 content in the vanadium-titanium iron ore. According to the status of vanadium-titanium iron ore resources at home and abroad, the TiO2 content in the pellet is in the range of 3%-13%;

[0045] ② During the blast furnace charging process, the proportion of vanadium-titanium iron ore in the blast furnace is increased by increasing the proportion of pellets (the proportion of pellets refers to the mass proportion of pellets in the iron charge of the blast furnace); the optimal proportion of pellets in the blast furnace iron charge is 100%. When the production capacity of the pellet production line is insufficient, sintered ore can be used to replace the insufficient part. The minimum production capacity of the pellet production line should ensure that the proportion of pellets in the blast furnace iron charge is greater than 30%.

[0046] ③ When the blast furnace pellet ratio has reached the upper limit, but the blast furnace vanadium-titanium iron ore ratio needs to be further increased, for example, when the pellet production line output can only ensure that the maximum proportion of pellets in the blast furnace iron material is 30%, but the blast furnace's desired vanadium-titanium iron ore ratio is greater than 60%, choose to add vanadium-titanium iron ore to the sintered ore;

[0047] ④ During the sintering batching process, the proportion of vanadium-titanium iron ore should not be too large to reduce the negative impact of TiO2 on the quality of sintered ore and blast furnace production, and the TiO2 content in the sintered finished ore should be controlled at <5%.

[0048] According to the above method, when the pellet ratio is not limited, that is, the pellet ratio = 100%, the blast furnace vanadium-titanium iron ore ratio can be 100%, and the TiO2 mass fraction in the blast furnace slag is 15% < 45%. When the pellet ratio is limited, it will affect the increase in the TiO2 mass fraction in the blast furnace slag and the increase in the proportion of vanadium-titanium iron ore in the blast furnace. Specifically, when 30% < pellet ratio < 100%, for low-titanium vanadium-titanium iron ore with a TiO2 content of <5.0% in the ore, the vanadium-titanium iron ore proportion of 100% can be achieved, and the TiO2 mass fraction in the blast furnace slag of 15% < 22%; when 30% < pellet ratio < 100%, for medium-titanium vanadium-titanium iron ore with a TiO2 content of 5%≤<8% in the ore, the blast furnace vanadium-titanium iron ore proportion of 100% can be achieved, and the TiO2 mass fraction in the blast furnace slag of 16% < 26%; when 30% < pellet ratio < 100%, for high-titanium vanadium-titanium iron ore with a TiO2 content of ≥8% in the ore, the blast furnace vanadium-titanium iron ore proportion of >60% can be achieved, and the TiO2 mass fraction in the blast furnace slag of 23% < 45%.

[0049] The above can be summarized as follows: the mass fraction of TiO2 in blast furnace slag can be 15% < 45%, and the proportion of vanadium-titanium iron ore in blast furnace can be > 60%.

[0050] Through the above ore blending, the vanadium-titanium iron ore ratio in the blast furnace is achieved at 60-100%. For vanadium-titanium iron ore with TiO2 content greater than 8% in the ore, by adjusting the vanadium-titanium pellet ratio to more than 50%, the titanium load into the furnace can be 110-220kg / t.

[0051] (3) Thermal system

[0052] Furnace temperature is the foundation of stable blast furnace production and a crucial indicator for assessing furnace conditions. For vanadium-titanium iron ore smelting, excessively low furnace temperatures can lead to thinning of the soft melting zone, uneven initial gas flow distribution, localized gas ducting in the charge column, irregular material feeding, material deviation, and material collapse. Excessively high furnace temperatures can cause the excessive generation of Ti(C,N), resulting in sticky slag and iron, foamy slag, difficulty separating slag and iron, hearth adhesion, increased blast furnace pressure differential, and disruption of normal production. By simulating and analyzing the temperature field distribution within the furnace and calculating the thermodynamic and kinetic conditions for Ti(C,N) generation, it was concluded that to ensure smooth furnace conditions, the target range for furnace temperature control must be determined based on the TiO2 mass fraction in the blast furnace slag.

[0053] On the other hand, for vanadium-titanium iron ore smelting, it is necessary to minimize the reduction and dissolution of vanadium in the molten iron to maximize vanadium resource utilization. Furnace temperature is a key factor in determining the distribution coefficient (Lv) of vanadium between molten iron and slag. Maintaining an appropriate furnace temperature is crucial for achieving a good vanadium distribution coefficient (Lv). Here, the vanadium distribution coefficient (Lv) = [V] / (V2O5), where [V] refers to the mass percentage of vanadium in the molten iron, and (V2O5) refers to the mass percentage of V2O5 in the slag.

[0054] The present invention adjusts the furnace temperature by adjusting the mass ratio of iron and fuel, the amount of coal injection and the temperature of hot coal gas, and the furnace temperature level is fed back by detecting the mass fraction of [Si] and [Ti] in the molten iron. Specifically:

[0055] ① Reasonable furnace temperature control range

[0056] When the mass fraction of TiO2 in blast furnace slag is 15% or less than 18%, the sum of the mass fractions of [Si] and [Ti] in molten iron should be controlled to be 0.4% or less than 0.8%;

[0057] When the mass fraction of TiO2 in blast furnace slag is 18% ≤ 20%, the sum of the mass fractions of [Si] and [Ti] in molten iron should be controlled to be 0.3% ≤ 0.7%;

[0058] When the mass fraction of TiO2 in blast furnace slag is 20% ≤ 25%, the sum of the mass fractions of [Si] and [Ti] in molten iron should be controlled to be 0.10% ≤ 0.6%;

[0059] When the mass fraction of TiO2 in blast furnace slag is greater than 25%, the sum of the mass fractions of [Si] and [Ti] in molten iron should be controlled at 0.05%≤≤0.55%.

[0060] ② Reasonable ore-coke ratio and ore-coal ratio

[0061] The blast furnace iron and coke are charged from the top of the furnace at a mass ratio of 5.5-7.5:1 for iron:coke, and the iron and pulverized coal are charged and sprayed into the furnace at a mass ratio of 15-40:1 for iron:coal.

[0062] When the furnace temperature is temporarily low, the amount of coal injected into the blast furnace can be adjusted to reduce the ratio of iron material to coal powder; when the furnace temperature is temporarily high, the amount of coal injected into the blast furnace can be adjusted to increase the ratio of iron material to coal powder;

[0063] When the furnace temperature is too low for a long time, the amount of coke fed into the blast furnace can be adjusted to reduce the ratio of iron to coke; when the furnace temperature is too high for a long time, the amount of coke fed into the blast furnace can be adjusted to increase the ratio of iron to coke.

[0064] By controlling these parameters, combined with a reasonable charging system and injection parameters, it is possible to achieve a blast furnace fuel ratio of less than 400 kg / t and a coke ratio of less than 300 kg / t. Typical values ​​range from 50-100 kg / t coal ratio and 260-280 kg / t coke ratio. The distribution coefficient of vanadium between molten iron and slag, [V] / (V2O5), is greater than 1.1.

[0065] (4) Loading system

[0066] The charging system of a blast furnace plays an important role in the distribution of coal gas flow, the energy utilization rate of the blast furnace, and the smooth operation of the furnace. The charging of a blast furnace is achieved through the top charging equipment. Currently, there are two types of charging equipment: the minute top and the bell-less top. The parameters of the same type of charging equipment vary greatly for blast furnaces of different volumes. For example, for the same bell-less top, the charge will fall at different points in the furnace depending on the different distribution angles. Therefore, a unified method is needed to specify the distribution of the charge in the furnace. This invention focuses on the bell-less top and provides a reasonable distribution method.

[0067] The specific charging method is as follows: A horizontal section of the blast furnace is taken at the charge level. The circle encompassing the section is divided into 11 equal-area rings, numbered from inner to outer: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11. The charging system is as follows: 60%-80% of the coke is distributed in rings 9-11 and 1-5, 20%-40% of the coke is distributed in rings 6-8, 70%-90% of the iron is distributed in rings 4-10, and 10%-30% of the iron is distributed in rings 1-3 and 11.

[0068] Because vanadium-titanium sinter and pellets are more severely pulverized during the reduction process in the blast furnace than conventional ores, oxygen blast furnaces require high iron ore strength to ensure good air permeability. Generally, pellets must have a compressive strength of 2500N or greater, which increases raw material processing costs, energy consumption, and carbon emissions. The present invention, through the above-mentioned distribution system, increases the proportion of vanadium-titanium ore. Even under conditions of relatively low iron ore strength, the blast furnace can still achieve suitable air permeability, smooth material discharge, and high iron production. Experimental verification has shown that by adopting this distribution system, the compressive strength of pellets can be reduced to a minimum of 1800N without affecting normal blast furnace production and technical and economic indicators.

[0069] (5) Tuyere injection parameters

[0070] In blast furnace production, the combustion reaction of carbon in front of the tuyere (reaction product CO) is the primary source of heat and reducing agent. The materials injected into the tuyere of a traditional blast furnace include hot air, oxygen, and pulverized coal. While releasing the same amount of heat and CO, the traditional blast furnace process introduces a large amount of nitrogen. This nitrogen does not participate in the reduction reaction of iron oxides, but instead serves to increase blast kinetic energy, stir the air, and activate the furnace.

[0071] Especially during the vanadium-titanium smelting process, stricter requirements for blast energy are required to suppress the formation of Ti(C,N). Insufficient blast energy can cause localized inactivity in the hearth. In these inactive areas, the Ti element spends more time in the furnace, increasing the formation of Ti(C,N). This, in turn, makes the slag sticky and makes it difficult to separate the slag from the iron. The amount of bosh gas is a key parameter affecting blast energy and hearth activity.

[0072] The method of smelting high-proportion vanadium-titanium iron ore in an oxygen blast furnace of the present invention is different from the injection process of a traditional blast furnace. The substances injected into the blast furnace tuyere of the present invention include hot coal gas, oxygen and coal powder. Only a small amount of carbon needs to be burned to meet the heat and reducing agent requirements in the furnace. However, in order to meet the reasonable blast kinetic energy and hearth activity requirements, it is necessary to control the reasonable amount of furnace gas. Production tests have shown that the amount of furnace gas in the oxygen blast furnace for smelting high-proportion vanadium-titanium iron ore is controlled at 1200Nm 3 / t-1750Nm 3 / t range is more appropriate. Based on this bosh gas volume parameter and the amount of coke to be burned in the furnace, the tuyere injection parameters are further determined as follows:

[0073] The amount of hot gas injected into the furnace in the present invention is 700Nm 3 / t-1280Nm 3 / t, the amount of oxygen injected into the furnace is 145Nm 3 / t-245Nm 3 / t. Among them, hot gas is the gas heated by the gas heating furnace, which includes coke oven gas, water vapor and purified gas. The input amount of coke oven gas delivered to the gas heating furnace is 20Nm 3 / t-200Nm 3 / t, the ratio of water vapor to coke oven gas delivered to the gas heating furnace is 0.10-0.30 mol:1 mol.

[0074] The present invention mixes a portion of coke oven gas, water vapor, and purified coal gas and delivers it to a gas heater. The purpose of adding water vapor to the mixed gas is to initiate a series of reforming reactions between the water vapor and the coke oven gas, reforming complex hydrocarbons into H2 and CO. For example, CH4 + H2O → CO + H2, and C2H2 + H2O → CO + H2. The water vapor mixing ratio is determined based on the composition of the coke oven gas and the thermodynamic and kinetic calculations of the reactions within the heater. The optimal range is a water vapor to coke oven gas ratio of 0.10-0.30:1 within the gas heater.

[0075] According to the above injection parameter control, the top gas produced by the blast furnace becomes purified gas after removing dust, CO2 and H2O. The amount of this purified gas is greater than the amount of purified gas required by the gas heating furnace, and the surplus is provided to external users, thus realizing the semi-sealed circulation recovery of gas.

[0076] Because the compressed air used for pulverized coal injection contains approximately 79% N₂, the furnace top equipment needs to be sealed and purged with N₂, and coke oven gas also contains 6%-10% N₂. Therefore, the present invention cannot achieve smelting in a zero-nitrogen environment. After the gas is free of dust, CO₂, and H₂O, N₂ concentrations are easily accumulated during recycling. However, by controlling the injection parameters described above and recovering the gas through a semi-sealed gas cycle, whereby a portion of the N₂-enriched purified gas is exported for use by other users and supplemented with a portion of the coke oven gas reformed with a low N₂ content, which is then heated and injected into the furnace, the volume percentage of N₂ in the furnace top gas after system equilibration is less than 25%, and more preferably in the range of 7-15%. This is a significant reduction compared to the 45%-60% volume percentage of N₂ in conventional blast furnace gas.

[0077] There are two functions of adding coke oven gas reforming gas to the heating furnace: one is to increase the kinetic energy of the blast and ensure the activity of the furnace hearth; the other is to dilute the N2 content of the gas in the furnace.

[0078] Thermodynamic calculations show that when vanadium-titanium iron ore is smelted in a blast furnace, the generation of Ti(C,N) in the furnace is closely related to the N2 content. The starting temperatures of reactions (1) and (2) are 1136°C and 1108°C, respectively, which means that TiN is generated slightly earlier than TiC. In fact, pure TiN and TiC rarely exist in the blast furnace. Instead, they form a complex solid solution that promotes each other's generation.

[0079] TiO2+3C=TiC+2CO ΔG θ =524130-333.55T(J / mol) (1)

[0080]

[0081] Critical precipitation of TiC for:

[0082] Critical temperature for TiN precipitation for:

[0083] Critical precipitation of Ti(C,N) for:

[0084] Due to the high N2 content in conventional blast furnaces, when the slag (TiO2) reaches 23% by mass, the Ti(C,N) generated within the furnace will prevent normal blast furnace production. The present invention reduces the N2 partial pressure and increases the CO partial pressure. Simultaneously, by monitoring the sum of the [Si] and [Ti] mass fractions in the molten iron to control the furnace temperature T, these factors effectively suppress Ti(C,N) formation. Experiments have shown that controlling the N2 volume fraction in the top gas to less than 25% can maintain a slag (TiO2) mass fraction of 45%, maintaining good slag-iron separation and slag fluidity, and maintaining stable and normal blast furnace production.

[0085] Furthermore, in the smelting method of the present invention, a portion of the coke oven gas, water vapor, and purified coal gas are mixed and transported into a gas heating furnace, where they are heated to form hot coal gas. The hot coal gas has a temperature range of 900°C to 2300°C. Within the 900°C to 2300°C range, the higher the hot coal gas temperature, the more conducive it is to reducing the blast furnace's solid fuel ratio and carbon emissions, where the solid fuel ratio includes the coal ratio and the coke ratio. Furthermore, the gas heating furnace can be heated electrically, by a hot blast furnace, or by plasma gas. The ultimate goal is to obtain high-temperature coal gas at a low cost. Depending on current technological levels, different heating equipment can achieve different hot coal gas temperatures. The most economical method is recommended to use hot blast furnace heating to achieve a coal gas temperature of 1250-1280°C.

[0086] Example 1: Smelting of high-titanium slag from high-titanium vanadium-titanium iron ore resources

[0087] The composition of a high-titanium vanadium-ilmenite ore from a certain place is shown in Table 1:

[0088] Table 1: Composition of vanadium-titanium iron ore in Example 1

[0089] Element TFe <![CDATA[TiO2]]> <![CDATA[V2O5]]> MgO <![CDATA[Al2O3]]> CaO <![CDATA[SiO2]]> Mass ratio / % 56.902 10.242 0.714 3.066 3.334 0.493 2.806

[0090] The above-mentioned vanadium-titanium iron ore is used to produce pellets. No other iron-containing raw materials are added during the ore blending process. The composition of the produced pellets is shown in Table 2:

[0091] Table 2: Composition of pellets produced from vanadium-titanium iron ore in Example 1

[0092] Element TFe <![CDATA[TiO2]]> <![CDATA[V2O5]]> MgO <![CDATA[Al2O3]]> CaO <![CDATA[SiO2]]> Mass ratio / % 52.4 9.4 0.7 3.2 3.5 4 3.6

[0093] The blast furnace iron charge contains 100% pellets, with no sinter or lump added. The blast furnace vanadium-titanium iron ore content is 100%. The composition of the resulting blast furnace slag is shown in Table 3:

[0094] Table 3: Composition of blast furnace slag produced in Example 1

[0095] Element <![CDATA[SiO2]]> CaO MgO <![CDATA[Al2O3]]> <![CDATA[TiO2]]> <![CDATA[V2O5]]> Mass ratio / % 18.30 20.13 12.71 14.98 31.25 0.38

[0096] The method for smelting high-proportion vanadium-titanium iron ore in an oxygen blast furnace according to the present invention (including a thermal system, charging method, and tuyere gas injection parameters) yields the following results: a vanadium content of 0.536% in molten iron, a coke ratio of 260 kg / t, a coal ratio of 100 kg / t, a vanadium distribution coefficient between molten iron and slag of [V] / (V2O5) = 1.35, which is greater than 1.3; a titanium loading of 180 kg / t in the combined feedstock; and a slag (TiO2) content of 31.25%, far exceeding the current international leading level (titanium loading of 110-130 kg / t and slag TiO2 content of 22-23%). Compared to conventional blast furnaces, the smelting method of the present invention reduces fuel and power costs by 57 yuan per ton of iron. Furthermore, because the price of vanadium-titanium iron ore is lower than that of ordinary iron ore, the ore blending cost of the present invention is reduced by 420 yuan per ton, and CO2 emissions are reduced by 33.3%.

[0097] Example 2: Smelting of titanium slag from high-titanium vanadium-titanium iron ore resources

[0098] The composition of a high-titanium vanadium-titanium iron ore from a certain place is shown in Table 4:

[0099] Table 4: Composition of vanadium-titanium iron ore in Example 2

[0100] Element TFe <![CDATA[TiO2]]> <![CDATA[V2O5]]> MgO <![CDATA[Al2O3]]> CaO <![CDATA[SiO2]]> Mass ratio / % 56.902 10.242 0.714 3.066 3.334 0.493 2.806

[0101] The above-mentioned vanadium-titanium iron ore is used to produce pellets. No other iron-containing raw materials are added during the ore blending process. The composition of the produced pellets is shown in Table 5:

[0102] Table 5: Composition of pellets produced from vanadium-titanium iron ore in Example 2

[0103] Element TFe <![CDATA[TiO2]]> <![CDATA[V2O5]]> MgO <![CDATA[Al2O3]]> CaO <![CDATA[SiO2]]> Mass ratio / % 54.915 9.703 0.685 2.968 3.38 0.668 3.546

[0104] Due to insufficient pelletizing capacity, to achieve optimal sinter metallurgical properties, for vanadium-titanium iron ores with TiO2 contents exceeding 8%, it is recommended that pellets comprise >50% of the blast furnace iron charge. For example, the blast furnace charge ratio should be 60% pellets and 40% sinter, with no lump ore added. The TiO2 content of the sinter is controlled to <3.5 to achieve optimal sinter metallurgical properties. To this end, vanadium-titanium iron ores are prioritized for pelletizing, with the remainder used for sintering. The iron feedstock for sintering is composed of both vanadium-titanium iron ores and other iron ores. By controlling the TiO2 content of the vanadium-titanium sinter to <3.5, the metallurgical properties of the vanadium-titanium sinter can be significantly improved. This eliminates the need for specialized control of the MgO content in the sinter, reduces the amount of high-MgO flux added during sintering, and ultimately reduces production costs. The sinter composition is shown in Table 6, resulting in a vanadium-titanium iron ore content exceeding 75% in the blast furnace.

[0105] Table 6: Composition of sintered ore in Example 2

[0106] Element TFe <![CDATA[SiO2]]> CaO MgO <![CDATA[Al2O3]]> <![CDATA[TiO2]]> <![CDATA[V2O5]]> Mass ratio / % 47.96 6.72 16.80 1.75 2.64 3.13 0.20

[0107] Compared with traditional smelting, after implementation, the drum strength of sintered ore increased from an average of 72.0% to an average of 77.3%, and after implementation, the drum strength of sintered ore was >76%; the low-temperature reduction differentiation rate of sintered ore improved from an average of 55% to an average of 26.1%, and after implementation, the low-temperature reduction pulverization rate of sintered ore was <30%.

[0108] The composition of the generated blast furnace slag is shown in Table 7. The experiment verified that in order to improve the fluidity of the slag, the slag basicity R2 needs to be controlled to be less than 1.12 for the smelting of high-proportion vanadium-titanium iron ore.

[0109] Table 7: Composition of blast furnace slag produced in Example 2

[0110] Element <![CDATA[SiO2]]> CaO MgO <![CDATA[Al2O3]]> <![CDATA[TiO2]]> <![CDATA[V2O5]]> Mass ratio / % 24.824 26.195 8.565 14.065 23.571 0.290

[0111] The method for smelting high-proportion vanadium-titanium iron ore in an oxygen blast furnace according to the present invention (including a thermal system, charging method, and tuyere gas injection parameters) yields 0.313% vanadium in the molten iron, a coke ratio of 270 kg / t, a coal ratio of 100 kg / t, a vanadium distribution coefficient between the molten iron and slag of [V] / (V2O5) = 1.38, which is greater than 1.3, a titanium loading of 135 kg / t in the overall feedstock, and a slag (TiO2) content of 23.57%, exceeding current international leading levels. Compared to conventional blast furnaces, the smelting method reduces fuel and power costs by 57 yuan per ton of iron. Furthermore, because the price of vanadium-titanium iron ore is lower than that of ordinary iron ore, ore blending costs are reduced by 13 yuan per ton of iron, and CO2 emissions are reduced by 31.5%.

[0112] Example 3: Smelting of titanium slag from low-titanium vanadium-titanium iron ore resources

[0113] The composition of a low-titanium vanadium-titanium iron ore from a certain place is shown in Table 8:

[0114] Table 8: Composition of low-titanium vanadium-ilmenite ore in Example 3

[0115] Element TFe <![CDATA[TiO2]]> <![CDATA[V2O5]]> MgO <![CDATA[Al2O3]]> CaO <![CDATA[SiO2]]> Mass ratio / % 62.92 4.13 0.81 2.9 3.1 0.5 2.9

[0116] The above-mentioned vanadium-titanium iron ore is used to produce pellets. No other iron-containing raw materials are added during the ore blending process. Flux and binder are added during the ore blending process. The composition of the produced pellets is shown in Table 9:

[0117] Table 9: Composition of pellets produced from vanadium-titanium iron ore in Example 3

[0118] Element TFe <![CDATA[TiO2]]> <![CDATA[V2O5]]> MgO <![CDATA[Al2O3]]> CaO <![CDATA[SiO2]]> Mass ratio / % 57.9 3.8 0.8 3.2 3.5 4.1 3.6

[0119] The blast furnace iron charge contains 100% pellets, with no sinter or lump added. The blast furnace vanadium-titanium iron ore content is 100%. The composition of the resulting blast furnace slag is shown in Table 10:

[0120] Table 10: Composition of blast furnace slag produced in Example 3

[0121] Element <![CDATA[TiO2]]> <![CDATA[V2O5]]> MgO <![CDATA[Al2O3]]> CaO <![CDATA[SiO2]]> Mass ratio / % 16.5 0.32 12.2 14.5 19.1 16.8

[0122] The oxygen blast furnace smelting method for high-proportion vanadium-titanium iron ore (including the thermal system, charging method, and tuyere gas injection parameters) according to the present invention achieves 0.767% vanadium content in molten iron, a coke ratio of 260 kg / t, a coal ratio of 90 kg / t, and a vanadium distribution coefficient between molten iron and slag of [V] / (V2O5) = 1.51, which is greater than 1.3. Compared with conventional blast furnaces, the present smelting method reduces fuel and power costs by 53 yuan per ton of iron. Furthermore, because the price of vanadium-titanium iron ore is lower than that of ordinary iron ore, the ore blending cost of the present invention is reduced by 310 yuan per ton, and CO2 emissions are reduced by 35.2%.

[0123] Example 4: Smelting of titanium slag from low-titanium vanadium-titanium iron ore resources

[0124] The composition of a low-titanium vanadium-ilmenite ore from a certain place is shown in Table 11:

[0125] Table 11: Composition of low-titanium vanadium-ilmenite ore in Example 4

[0126] Element TFe <![CDATA[TiO2]]> <![CDATA[V2O5]]> MgO <![CDATA[Al2O3]]> CaO <![CDATA[SiO2]]> Mass ratio / % 62.92 4.13 0.81 2.9 3.1 0.5 2.9

[0127] Due to insufficient output from the pelletizing line, the ore mix for the blast furnace is 55% acidic pellets and 45% basic sinter, with no lump ore added. The above-mentioned vanadium-titanium iron ore is used to produce pellets. No other iron-containing raw materials or flux are added during the pelletizing process. Instead, a binder is added during the pelletizing process. The composition of the pellets produced is shown in Table 12:

[0128] Table 12: Composition of pellets produced from vanadium-titanium iron ore in Example 4

[0129] Element TFe <![CDATA[TiO2]]> <![CDATA[V2O5]]> MgO <![CDATA[Al2O3]]> CaO <![CDATA[SiO2]]> Mass ratio / % 62.10 4.08 0.80 2.91 3.16 0.67 3.84

[0130] Vanadium-titanium iron ore is used first in pellet production, with the remainder used in sintering production. The TiO2 content of the sintered ore is controlled to be less than 3.5 to obtain better metallurgical properties of the sintered ore. After balancing, it can be found that when the proportion of vanadium-titanium iron ore in the iron raw material of sintering production is 100%, the TiO2 content of the sintered ore can be satisfied to be less than 3.5. At this time, the proportion of vanadium-titanium iron ore in the blast furnace is 100%. The composition of the sintered ore is shown in Table 13:

[0131] Table 13: Composition of sintered ore produced from vanadium-titanium iron ore in Example 4

[0132]

[0133] The composition of the generated blast furnace slag is shown in Table 14:

[0134] Table 14: Composition of blast furnace slag produced in Example 4

[0135] Element <![CDATA[TiO2]]> <![CDATA[V2O5]]> MgO <![CDATA[Al2O3]]> CaO <![CDATA[SiO2]]> Mass ratio / % 16.5 0.32 12.2 14.5 19.1 16.8

[0136] The oxygen blast furnace smelting method for high-proportion vanadium-titanium iron ore (including the thermal system, charging method, and tuyere gas injection parameters) according to the present invention achieves 0.767% vanadium in the molten iron, a coke ratio of 260 kg / t, a coal ratio of 90 kg / t, and a vanadium distribution coefficient between the molten iron and slag of [V] / (V2O5) = 1.53, which is greater than 1.3. Compared with conventional blast furnaces, the present smelting method reduces fuel and power costs by 53 yuan per ton of iron. Furthermore, because the price of vanadium-titanium iron ore is lower than that of ordinary iron ore, the ore blending cost of the present invention is reduced by 310 yuan per ton, and CO2 emissions are reduced by 35.2%.

[0137] Example 5: Top gas circulation example

[0138] The composition of steel plant coke oven gas is shown in Table 15 below.

[0139] Table 15: Composition of coke oven gas in Example 5

[0140] Element <![CDATA[H2]]> CO <![CDATA[N2]]> <![CDATA[CO2]]> <![CDATA[CH4]]> <![CDATA[C2H2]]> <![CDATA[O2]]> content / % 59.7 7.9 7.8 2.4 20.0 2.0 0.2

[0141] The composition of the reducing gas obtained after reforming coke oven gas and water vapor in the heating furnace is shown in Table 16 below. The coke oven gas flow rate is 75m 3 / t, the steam flow rate is 15.9m 3 / t.

[0142] Table 16: Composition of the reducing gas after coke oven gas reforming in Example 5

[0143] Element <![CDATA[H2]]> CO <![CDATA[N2]]> content / % 67.9 27.4 4.7

[0144] According to the coke ratio of 0.26t / t and coal ratio of 0.07t / t, the oxygen blowing amount at the tuyere is 191Nm 3 / t operation, which comes from carbon combustion in the furnace tuyere, direct reduction, heating furnace hot gas, etc. The composition of the bosh gas generated in the furnace is shown in Table 17 below. The bosh gas volume is 1500m 3 / t.

[0145] Table 17: Bosh gas composition of Example 5

[0146] Element <![CDATA[H2]]> CO <![CDATA[N2]]> content / % 13.59 72.50 13.91

[0147] During the rising process, the furnace gas reacts with the iron oxide in the furnace to produce metallic iron, H2O and CO2. When the gas reaches the furnace top, the composition of the furnace top gas is shown in Table 18 below. The furnace top gas volume is 1500m 3 / t.

[0148] Table 18: Composition of top gas in Example 5

[0149] Element <![CDATA[H2]]> CO <![CDATA[N2]]> <![CDATA[CO2]]> <![CDATA[H2O <!-- 10 -->]]> content / % 8.44 43.58 13.91 28.92 5.15

[0150] The composition of the purified gas after removing CO2, H2O and dust from the top gas is shown in Table 19 below. The purified gas volume is 989m 3 / t. It can be seen that N2 is enriched in the purified gas. If a part of it is not transported out, N2 will be further enriched and rise to more than 25% after the next round or multiple rounds of recycling. Therefore, the purified gas volume is 989m 3 55m in / t 3 / t of purified gas is delivered to other users, 934m 3 / t of purified gas is transported to the heating furnace for heating and then supplied to the blast furnace for recycling, but this 934m 3 The purified gas per tonne cannot meet the blast energy requirements of the blast furnace, so a portion of coke oven gas reformed gas is added. This supplemental coke oven gas reformed gas has two functions: first, it increases blast energy and ensures furnace activity; second, it dilutes the nitrogen content of the gas in the furnace.

[0151] Table 19: Composition of purified coal gas in Example 5

[0152] Element <![CDATA[H2]]> CO <![CDATA[N2]]> content / % 12.81 66.10 21.09

[0153] 934m 3 / t of purified coal gas enters the next round of recycling process: in the gas heating furnace, the purified coal gas with a N2 content of 21.09% is mixed with the coke oven gas reforming gas with a N2 content of 4.7% to become high-temperature reducing gas, which is then fed into the furnace. It is then mixed with the CO produced by the combustion and reduction reaction of carbon in the furnace to become bosh gas with a N2 content of 13.91%. This cycle is repeated until the N2 content of the coal gas in the furnace stabilizes at around 13.91%.

[0154] In summary, the smelting method of the present invention achieves blast furnace smelting with a vanadium-titanium iron ore ratio greater than 60%, a TiO2 mass fraction in the blast furnace slag greater than 15% and less than 45%, and a CO2 emission reduction of more than 30%.

[0155] Although the specific embodiments of the present invention are described in detail in conjunction with the accompanying drawings, this should not be construed as limiting the scope of protection of this patent. Within the scope described by the claims, various modifications and variations that can be made by those skilled in the art without creative work still fall within the scope of protection of this patent.

Claims

1. A method for smelting high-proportion vanadium-titanium iron ore in an oxygen blast furnace, characterized in that: The following steps are involved: The blast furnace uses pure oxygen injection, with pure oxygen, hot coal gas and pulverized coal injected into the tuyere; iron and coke are added from the top of the furnace; the volume percentage of nitrogen in the top gas is less than 25%; the top gas is recycled after CO2 is removed; The iron material is pelletized ore or the iron material is pelletized ore and at least one of the following materials: sintered ore and lump ore; The TiO2 content in the pellets is 3%-13%, the iron raw material used to produce the pellets is vanadium-titanium iron ore, and the mass proportion of the pellets in the iron feed of the blast furnace is greater than 30%; the mass fraction of TiO2 in the sintered ore is less than 5%; The mass fraction of TiO2 in the blast furnace slag generated by smelting is greater than 15% and less than 45%, the proportion of vanadium-titanium iron ore in the blast furnace is greater than 60%, and the CO2 emission of the blast furnace is reduced by 30%; The hot gas is the gas heated by the gas heating furnace. The gas sources in the gas heating furnace include coke oven gas, water vapor and purified gas. The flow rate of coke oven gas fed into the gas heating furnace is 20Nm 3 / t-200Nm 3 / t, the ratio of water vapor to coke oven gas fed into the heating furnace is 0.10-0.30:1; The mass ratio of blast furnace iron material to coke is 5.5-7.5:1, and the mass ratio of blast furnace iron material to coal powder is 15-40:1; in blast furnace smelting, the blast furnace fuel ratio is less than 400kg / t, and the coke ratio is less than 300kg / t.

2. The method for smelting high-proportion vanadium-titanium iron ore in an oxygen blast furnace according to claim 1, characterized in that: During the blast furnace smelting process, When the mass fraction of TiO2 in blast furnace slag is greater than 15% and less than or equal to 18%, the sum of the mass fractions of [Si] and [Ti] in molten iron is greater than or equal to 0.4% and less than or equal to 0.8%; When the mass fraction of TiO2 in blast furnace slag is greater than 18% and less than or equal to 20%, the sum of the mass fractions of [Si] and [Ti] in molten iron is greater than or equal to 0.3% and less than or equal to 0.7%; When the mass fraction of TiO2 in blast furnace slag is greater than 20% and less than or equal to 25%, the sum of the mass fractions of [Si] and [Ti] in molten iron is greater than or equal to 0.10% and less than or equal to 0.6%; When the mass fraction of TiO2 in blast furnace slag is greater than 25%, the sum of the mass fractions of [Si] and [Ti] in molten iron shall be ≥0.05% and ≤0.55%.

3. The method for smelting high-proportion vanadium-titanium iron ore in an oxygen blast furnace according to claim 1, characterized in that: During blast furnace smelting, the distribution coefficient of vanadium in molten iron and slag [V] / (V2O5) is greater than 1.

1.

4. The method for smelting high-proportion vanadium-titanium iron ore in an oxygen blast furnace according to claim 1, characterized in that: The flow rate of the hot gas injected is 700Nm 3 / t-1280Nm 3 / t, the flow rate of the pure oxygen injected is 145Nm 3 / t-245Nm 3 / t.

5. The method for smelting high-proportion vanadium-titanium iron ore in an oxygen blast furnace according to claim 1, characterized in that: The charging method of the iron material and coke is as follows: at the height of the blast furnace charge surface, take a horizontal section of the blast furnace, divide the circle where the section is located into 11 equal-area circular rings, and number them in sequence from the inner ring to the outer ring. The charging system is: 60%-80% of the coke is distributed in rings 9-11 and rings 1-5, 20%-40% of the coke is distributed in rings 6-8, 70%-90% of the iron material is distributed in rings 4-10, and 10%-30% of the iron material is distributed in rings 1-3 and 11.

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