Method for smelting high-proportion sefstromite through oxygen blast furnace

Abstract

The invention discloses a method for smelting high-proportion sefstromite in an oxygen blast furnace, which comprises the following steps: pure oxygen injection is adopted in the blast furnace, pure oxygen, hot coal gas and pulverized coal are injected from a tuyere, an iron material and coke are added from the top of the furnace, the volume percentage of N2 in the top coal gas is less than 25%, and the top coal gas is recycled after CO2 is removed. By means of the method for smelting the high-proportion sefstromite through the oxygen blast furnace, smelting that the proportion of the sefstromite in the blast furnace is larger than 60%, the mass fraction of TiO2 in the blast furnace slag is larger than 15% and smaller than 45%, and CO2 emission is reduced by 30% or above can be achieved, and the problem that in existing blast furnace smelting, when the proportion of the sefstromite is increased, the cost is low is solved. The problems that slag is thick, slag and iron are difficult to separate, furnace conditions are unsmooth, cost is high, carbon emission is high and the like exist in the prior art, so that the utilization efficiency of vanadium-titanium resources is higher, and smelting cost and carbon emission are lower.

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] At present, the main technically mature ironmaking processes include blast furnace ironmaking, smelting reduction (HIsmelt, COREX, Finex), direct reduction (gas-based direct reduction, coal-based direct reduction), etc. However, these processes have their 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 that it is overly dependent on high-quality metallurgical coke and requires supporting construction of coking, sintering, and pelletizing, which requires large system investment. The blast furnace is difficult to operate and difficult to recover after abnormal and fluctuating furnace conditions. The cost, carbon emissions, and energy consumption are high. At the same time, the N in the traditional blast furnace is 2 The content accounts for more than 40% of the total gas phase, which is very easy to generate Ti(C,N), forming foamy slag in the furnace, which is not conducive to smooth production and index 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 / t iron, flue gas temperature reaches 1600℃, a large amount of physical heat is lost outside the furnace with the flue gas, high iron loss, high fuel consumption, and high carbon emissions; ② COREX and Finex hot metal [Si] content is high, the amount of gas generated is too large, and the primary carbon consumption is high; ③ The chemical energy utilization rate of carbon is insufficient, and part of the carbon element escapes with the gas in the form of CO, and its chemical energy cannot be further utilized;

[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 there is the same problem as gas-based vertical furnaces that have high requirements for ore quality.

[0006] Vanadium-titanium magnetite is a composite ore with multiple metal elements, and is a symbiotic magnetic iron ore mainly containing iron, vanadium and titanium. Vanadium-titanium magnetite is the most important raw material resource for the production of vanadium in the world, and is also the main mineral raw material for refining Ti and Fe. At the same time, vanadium-titanium magnetite is also recognized as one of the difficult-to-smelt minerals in the world, and its comprehensive utilization is difficult.

[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, it is difficult to increase the proportion of vanadium-titanium ore. In the prior art, when the proportion of vanadium-titanium iron ore in the blast furnace (the vanadium-titanium iron ore proportion 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 pelletized ore to the total amount of iron-containing raw materials used to produce sintered ore and pelletized ore and the sum of the amount of iron-containing lump ore used in the blast furnace) increases, there is a blast furnace slag (TiO 2 ) content increases, Ti(C, N), TiC, and TiN are produced, 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 content of (TiO 2 ) content increases, which will cause a series of technical problems such as reduced sintering drum strength, increased reduction pulverization, deterioration of blast furnace operation, irregular furnace conditions, increased sintering return rate, and increased fuel cost per ton of iron.

[0009] Second, the process has high carbon emissions and high energy consumption. CO accounts for about 20-30% of the blast furnace top gas. The chemical energy of this part of CO has not been effectively utilized in the existing technology, but is used by burning to generate electricity. The thermal energy conversion efficiency of blast furnace gas combustion to generate electricity is less than 40%. Therefore, the system has high energy consumption and high 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 prior art that the proportion of vanadium-titanium iron ore is difficult to increase during blast furnace smelting of vanadium-titanium iron ore, and the process has high carbon emissions and high costs.

[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, and pure oxygen, hot coal gas and coal powder are sprayed into the tuyere; iron and coke are added from the top of the furnace; the N 2 The volume percentage is less than 25%; CO removal from top gas 2 Post-recycling;

[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] TiO in pellets 2 The content 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 blast furnaces is more than 30%. 2 Content <5%;

[0015] TiO in blast furnace slag generated by smelting 2 The mass fraction of vanadium-titanium iron ore is greater than 15% and less than 45%, the proportion of vanadium-titanium iron ore in blast furnace is greater than 60%, and the proportion of CO in blast furnace is greater than 60%.2 Emissions reduced by 30%.

[0016] In one of the preferred solutions of the present invention, the hot gas is the gas heated by the gas heating furnace, the gas source in the gas heating furnace includes coke oven gas, water vapor and purified gas, wherein 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 TiO in blast furnace slag 2 When the mass fraction of [Si] is greater than 15% and less than or equal to 18%, the sum of the mass fractions of [Si] and [Ti] in the molten iron is greater than or equal to 0.4% and less than or equal to 0.8%;

[0019] When TiO in blast furnace slag 2 When the mass fraction of [Si] is greater than 18% and less than or equal to 20%, the sum of the mass fractions of [Si] and [Ti] in the molten iron is greater than or equal to 0.3% and less than or equal to 0.7%;

[0020] When TiO in blast furnace slag 2 When the mass fraction of [Si] is greater than 20% and less than or equal to 25%, the sum of the mass fractions of [Si] and [Ti] in the molten iron shall be greater than or equal to 0.10% and less than or equal to 0.6%;

[0021] When TiO in blast furnace slag 2 When the mass fraction of [Si] is greater than 25%, the sum of the mass fractions of [Si] and [Ti] in the molten iron shall be ≥0.05% and ≤0.55%.

[0022] In one of the preferred solutions 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 400kg / t, and the coke ratio is less than 300kg / t.

[0023] In one of the preferred embodiments of the present invention, the distribution coefficient of vanadium in molten iron and slag during blast furnace smelting is [V] / (V 2 O 5 )>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 schemes of the present invention is that the charging method of iron material and coke is 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 circular rings of equal area, and number them in sequence from the inner ring to the outer ring. The distribution system is as follows: 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.

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

[0027] 1. Solve the problem of viscous and foamy slag in vanadium-titanium iron ore smelting. 2 The volume percentage is less than 25%, which is comparable to the N 2 Compared with the traditional blast furnace, the volume percentage of N in the smelting process of the present invention is significantly reduced from 45% to 60%. 2 The reduction of partial pressure, the increase of CO partial pressure and the reasonable control of furnace temperature all effectively inhibit the formation of Ti(C,N), prevent the stickiness of slag and iron and the difficulty of separating slag and iron from the source, control the foamy slag, and thus solve one of the difficult problems affecting the increase of the proportion of vanadium-titanium iron ore in blast furnaces.

[0028] 2. Solve the problem of poor metallurgical properties of vanadium-titanium sintered ore. The present invention optimizes the ore blending structure and controls the TiO 2 The content is less than 5%, and as much vanadium-titanium iron ore as possible is added to the pelletizing ingredients, which solves a series of technical problems such as the reduced drum strength of vanadium-titanium sintered ore, high reduction powderization, and high return rate of ore, which lead to poor blast furnace operation, abnormal furnace conditions, and increased fuel cost per ton of sintering iron, thereby solving another difficult problem that affects the increase in the proportion of vanadium-titanium iron ore in blast furnaces.

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

[0030] 4. TiO in the slag of the present invention 2 The mass percentage is significantly increased. In traditional blast furnace smelting of vanadium-titanium iron ore, when TiO 2 When the mass percentage is less than 12%, the TiO 2 The mass percentage is less than 23%. The present invention can achieve TiO 2 The mass percentage is in the range of 15-45%, among which, when TiO 2When the mass percentage reaches 8%, TiO in blast furnace slag can be achieved. 2 The mass percentage reaches 27%; when TiO 2 When the mass percentage reaches 10%, TiO 2 The mass percentage reaches 30%; when TiO 2 When the mass percentage is greater than 12%, TiO in blast furnace slag can be 2 The mass percentage reaches 40%. TiO in blast furnace slag 2 The increase in mass percentage has greatly improved the utilization value of slag.

[0031] 5. Reduce blast furnace fuel costs and CO 2 The present invention adopts pure oxygen injection to remove CO from the top gas. 2 Post-heating spraying back into the furnace increases the amount of reducing gas CO in the furnace and reduces the amount of solid fuel that needs to be burned at the tuyere (the purpose of burning solid fuel at the tuyere is to provide heat and CO reducing gas). The solid fuel consumption is reduced by 30-40%, and the combined fuel and power costs are reduced by about RMB 50-100 / ton of molten iron (different prices in different regions result in different cost reduction data). BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The present invention 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, and the smelting method includes the following steps: adding blast furnace iron material and coke into the blast furnace 1, the blast furnace 1 adopts pure oxygen injection, and pure oxygen, hot coal gas and coal powder are injected into the tuyere for smelting, and liquid slag and molten iron are generated by smelting, and the slag and molten iron are discharged 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, the process flow of oxygen blast furnace smelting high-proportion vanadium-titanium iron ore 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 from the coal injection gun located in the direct blowing pipe of the air supply branch pipe, and the pulverized 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 from the small tuyere sleeve;

[0039] ② Blast furnace coke and iron materials are loaded into the furnace from the top of the blast furnace through the charging equipment, wherein the iron materials are pelletized ore or the iron materials are 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 into the tuyere sleeve and the gas generated by the chemical reaction in the furnace together form the bosh gas. During the upward movement of the bosh gas, it undergoes a physical and chemical reaction with the descending iron material to generate liquid slag and molten iron, which are discharged out of the furnace from the slag and iron outlet;

[0041] ④ The top gas generated by the reaction in the furnace is discharged from the top gas pipeline. The top gas is dedused and deCOed by the gas purification facility 2. 2 and dehydrogenation 2 After the smelting process, the purified coal gas is converted into clean coal gas, which reaches the coal gas pipeline network 3. A part of the clean coal gas is transmitted to other users for use, and the other part of the clean coal gas is mixed with coke oven gas and water vapor and transported to the coal gas heating furnace 4. After being heated, it becomes hot coal gas. The above-mentioned whole smelting process realizes the 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 TiO in the sintered ore. 2 Content <5%. Specifically:

[0044] ① In the process of pelletizing, 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. 2 The content of TiO in vanadium-titanium iron ore 2 The content is determined by the current status of vanadium-titanium iron ore resources at home and abroad. 2 The content is in the range of 3%-13%;

[0045] ② During the blast furnace batching 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 pelletizing line is insufficient, sintered ore can be used to replace the insufficient part. The minimum production capacity of the pelletizing line should ensure that the proportion of pellets in the blast furnace iron charge is greater than 30%.

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

[0047] ④ During the sintering process, the proportion of vanadium-titanium iron ore should not be too large to reduce the TiO 2 The negative impact on sinter quality and blast furnace production is shown in Table 1. 2 Content is 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%, 15% < TiO 2 Mass fraction <45%. When the pellet ratio is limited, it will affect the TiO in blast furnace slag 2 The mass fraction is increased and the proportion of vanadium-titanium iron ore in blast furnace is increased. Specifically, when 30% < pellet ratio < 100%, for TiO 2 Low-titanium vanadium-titanium iron ore with a content of less than 5.0% can achieve a vanadium-titanium ore ratio of 100%, 15% less than the TiO 2 Mass fraction < 22%; when 30% < pellet ratio < 100%, for 5% ≤ TiO 2 The content of medium titanium type vanadium-titanium iron ore is less than 8%, which can achieve 100% vanadium-titanium iron ore ratio in blast furnace, and 16% less than TiO 2 When the mass fraction is less than 26% and the pellet ratio is less than 100%, the TiO 2 The content of high titanium type vanadium-titanium iron ore is ≥8%, which can achieve the proportion of vanadium-titanium iron ore in blast furnace>60%, and 23%<TiO in blast furnace slag. 2 Mass fraction <45%.

[0049] The above summary is: 15% < TiO in blast furnace slag can be achieved 2 The mass fraction is less than 45%, and the proportion of blast furnace vanadium-titanium iron ore is greater than 60%.

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

[0051] (3) Heat system

[0052] Furnace temperature is the basis for stable production of blast furnaces and an important indicator for judging furnace conditions. For vanadium-titanium iron ore smelting, too low furnace temperature will cause the thinning of the soft melting zone in the furnace, uneven distribution of the initial gas flow, local gas pipelines in the material column, unsmooth material feeding, material deviation, and material collapse; too high furnace temperature will cause a large amount of Ti(C,N) to be generated, slag and iron to be sticky, foamy slag, slag and iron to be difficult to separate, furnace cylinder to stick, blast furnace pressure difference to rise, and production cannot proceed normally. By simulating and analyzing the temperature field distribution in the furnace, and calculating the thermodynamic and kinetic conditions for the generation of Ti(C,N), it is concluded that to ensure smooth furnace conditions, it is necessary to adjust the temperature according to the different TiO in the blast furnace slag. 2 Quality fraction, determine the target range of furnace temperature control.

[0053] On the other hand, for vanadium-titanium iron ore smelting, it is necessary to reduce and dissolve vanadium in molten iron as much as possible to improve the utilization rate of vanadium resources. The furnace temperature is an important factor in determining the distribution coefficient Lv of vanadium in molten iron and slag. Maintaining a suitable furnace temperature can achieve a better vanadium distribution coefficient Lv, where the vanadium distribution coefficient Lv = [V] / (V 2 O 5 ), [V] refers to the mass percentage of vanadium in the molten iron, (V 2 O 5 ) refers to V in slag 2 O 5 Mass percentage.

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

[0055] ① Reasonable furnace temperature control range

[0056] When 15% < TiO in blast furnace slag 2 When the mass fraction is ≤18%, the sum of the mass fractions of [Si] and [Ti] in the molten iron should be controlled to be 0.4%≤≤0.8%;

[0057] When 18% < TiO in blast furnace slag 2 When the mass fraction is ≤20%, the sum of the mass fractions of [Si] and [Ti] in the molten iron should be controlled to be 0.3%≤≤0.7%;

[0058] When 20% < TiO in blast furnace slag 2When the mass fraction is ≤25%, the sum of the mass fractions of [Si] and [Ti] in the molten iron should be controlled to be 0.10%≤≤0.6%;

[0059] When TiO in blast furnace slag 2 When the mass fraction of [Si] and [Ti] in the molten iron is greater than 25%, the sum of the mass fractions of [Si] and [Ti] in the molten iron should be controlled to be 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 furnace top 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:pulverized 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] According to the above parameter control, with reasonable charging system and injection parameters, the blast furnace fuel ratio can be less than 400kg / t, and the coke ratio can be less than 300kg / t. The typical value range is 50-100kg / t coal ratio and 260-280kg / t coke ratio. The distribution coefficient of vanadium in molten iron and slag [V] / (V 2 O 5 )>1.1.

[0065] (4) Loading system

[0066] The charging system of the blast furnace plays an important role in the gas flow distribution, energy utilization rate and furnace condition of the blast furnace. The charging of the blast furnace is realized by the charging equipment on the top of the furnace. At present, there are two types of charging equipment: the minute-type furnace top and the bell-free furnace top. For blast furnaces of different volumes, the parameters of the same type of charging equipment are also very different. For example, for the same bell-free furnace top, the falling points of the charge in the furnace corresponding to different distribution angles are different. Therefore, a unified method is needed to specify the distribution of the charge in the furnace. The present invention focuses on the bell-free furnace top and provides a reasonable distribution method.

[0067] The specific method of charging is as follows: at the height of the blast furnace charge surface, take the horizontal section of the blast furnace, divide the circle where the section is located into 11 equal-area circular rings, numbered from the inner ring to the outer ring as 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 and 11. The charging system is: 60%-80% of the coke is distributed in the 9th to 11th rings and the 1st to 5th rings, 20%-40% of the coke is distributed in the 6th to 8th rings, 70%-90% of the iron is distributed in the 4th to 10th rings, and 10%-30% of the iron is distributed in the 1st to 3rd rings and the 11th ring.

[0068] Since vanadium-titanium sintered ore and pellets are more severely pulverized than ordinary ores during the reduction process in the blast furnace, in order to make the oxygen blast furnace have good air permeability, the strength requirements of the iron ore entering the furnace are relatively high, and the compressive strength of the pellets is generally required to be ≥2500N, which increases the processing cost, energy consumption and carbon emissions of the raw materials. The present invention adopts the above distribution system, so that after the proportion of vanadium-titanium ore is increased, even under the condition of lower iron ore strength, the blast furnace can still obtain suitable air permeability, smooth material discharge and higher iron production. After experimental verification, by adopting the above distribution system, the compressive strength of the pellets can be reduced to 1800N at the lowest without affecting the normal production and technical and economic indicators of the blast furnace.

[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 main source of heat and reducing agent for the blast furnace. The substances injected into the tuyere of the traditional blast furnace include hot air, oxygen and pulverized coal. Under the condition of releasing the same heat and CO by combustion, the traditional blast furnace process introduces a large amount of N 2 , this part N 2 It does not participate in the reduction reaction of iron oxides, but plays a role in increasing the kinetic energy of the blast, stirring and activating the furnace.

[0071] Especially in the vanadium-titanium ore smelting process, in order to suppress the generation of Ti(C,N), the requirements for blast kinetic energy are more stringent. Insufficient blast kinetic energy will cause local inactivity of the furnace, and the residence time of Ti elements in the inactive parts of the furnace will increase, which will increase the generation of Ti(C,N), and make the slag sticky and the slag and iron difficult to separate. The amount of gas in the furnace is an important parameter affecting the blast kinetic energy and the activity of the furnace.

[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 at 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 requirements of blast kinetic energy and furnace activity, 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 1200Nm3 / t-1750Nm 3 / t range is more appropriate. Based on this furnace 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. The 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 them to the coal gas heating furnace, wherein the purpose of adding water vapor to the mixed gas is to cause a series of reforming reactions between the water vapor and the coke oven gas, so that the complex hydrocarbons are reformed to generate H 2 and CO, such as CH 4 +H 2 O→CO+H 2 , C 2 H 2 +H 2 O→CO+H 2 The mixing ratio of water vapor is determined based on the composition of coke oven gas, the thermodynamics of the reaction in the heating furnace and the kinetic calculation. The optimal value range is: the amount ratio of water vapor to coke oven gas in the gas heating furnace is 0.10-0.30:1.

[0075] According to the above injection parameters, the top gas produced by the blast furnace is removed from dust and CO 2 and dehydrogenation 2 O becomes purified gas, the amount of which is greater than the amount of purified gas required by the gas heating furnace, and the surplus is provided for external users, thus realizing the semi-sealed circulation recovery of gas.

[0076] Since the compressed air used for coal powder injection contains about 79% N 2 , furnace top equipment needs N 2 For sealing and purging, coke oven gas also contains 6%-10% N 2 Therefore, the present invention cannot achieve smelting in a zero nitrogen environment. 2 and H 2After O, the recycling process is likely to cause N 2 However, according to the above-mentioned injection parameters, the gas is semi-sealed and recycled, that is, N 2 Part of the enriched purified gas is exported for use by other users, and part of the N 2 The coke oven gas reforming gas with low N content is heated and sprayed into the furnace, so that the system is balanced and the N content in the furnace top gas is reduced. 2 The volume percentage is less than 25%, and the optimal range is 7-15%, which is different from the N content in traditional blast furnace gas. 2 The volume percentage is significantly reduced compared to 45%-60%.

[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, and the other is to dilute the N 2 content.

[0078] Thermodynamic calculations show that when smelting vanadium-titanium iron ore in a blast furnace, the generation of Ti(C,N) in the furnace is related to N 2 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 formation.

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

[0080]

[0081] Critical temperature for TiC precipitation for:

[0082] Criticality of TiN precipitation for:

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

[0084] Traditional blast furnaces have N 2 The content is high, when the slag (TiO 2 ) mass percentage reaches 23%, the Ti(C,N) generated in the furnace will make the blast furnace unable to produce normally. 2 The partial pressure of CO was reduced, the partial pressure of CO was increased, and at the same time, the furnace temperature T was controlled by monitoring the sum of the mass fractions of [Si] and [Ti] in the molten iron, which effectively suppressed the formation of Ti(C,N).2 Volume ratio is less than 25%, which can meet the requirements of slag (TiO 2 ) When the mass proportion reaches 45%, the slag-iron separation effect and slag fluidity are still good, and the blast furnace can still produce stably and normally.

[0085] In addition, in the smelting method of the present invention, a part of the coke oven gas, water vapor and purified coal gas are mixed and transported into the gas heating furnace, and become hot coal gas after heating, and the temperature range of the hot coal gas is 900℃-2300℃. Within the range of 900℃-2300℃, the higher the temperature of the hot coal gas, the more conducive it is to reduce the solid fuel ratio and carbon emissions of the blast furnace, wherein the solid fuel ratio includes the coal ratio and the coke ratio. At the same time, the gas heating furnace can adopt electric heating, hot blast furnace heating, or plasma gas heating. The ultimate goal is to obtain high-temperature coal gas at a low cost. According to the current technical level, different heating equipment can obtain different hot coal gas temperatures. The most economical method is to use hot blast furnace heating to obtain a coal gas temperature of 1250-1280℃.

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

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

[0088] Table 1: Example 1 Vanadium Titanium Iron Ore Composition Table

[0089] Element TFe <![CDATA[TiO 2 ]]> <![CDATA[V 2 THE 5 ]]> MgO <![CDATA[Al 2 THE 3 ]]> CaO <![CDATA[SiO 2 ]]> 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, and no other iron-containing raw materials are added in 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[TiO 2 ]]> <![CDATA[V 2 THE 5 ]]> MgO <![CDATA[Al 2 THE 3 ]]> CaO <![CDATA[SiO 2 ]]> Mass ratio / % 52.4 9.4 0.7 3.2 3.5 4 3.6

[0093] The proportion of blast furnace pellets in the blast furnace iron material is 100% pellets, no sintered ore and lump ore are added, and the proportion of vanadium-titanium iron ore in the blast furnace is 100%. The composition of the generated blast furnace slag is shown in Table 3:

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

[0095] Element <![CDATA[SiO 2 ]]> CaO MgO <![CDATA[Al 2 THE 3 ]]> <![CDATA[TiO 2 ]]> <![CDATA[V 2 THE 5 <!-- 7 --> ]]> Mass ratio / % 18.30 20.13 12.71 14.98 31.25 0.38

[0096] According to the method for smelting high-proportion vanadium-titanium iron ore in an oxygen blast furnace (including thermal system, charging method and tuyere gas injection parameters) of the present invention, the actual results obtained are: the [V] content in the molten iron is 0.536%, the coke ratio is 260kg / t, the coal ratio is 100kg / t, and the distribution coefficient of vanadium element in molten iron and slag is [V] / (V2 O 5 )=1.35>1.3, the titanium load of the comprehensive raw materials entering the furnace is 180kg / t, the slag (TiO 2 ) content reaches 31.25%, which is much higher than the current international leading level (titanium load into the furnace is 110-130kg / t, slag TiO 2 Compared with the traditional blast furnace, the fuel and power cost of the smelting method of the present invention is reduced by 57 yuan / ton of iron. Furthermore, since 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 / ton. 2 Physical emissions decreased 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 in a certain place is shown in Table 4:

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

[0100] Element TFe <![CDATA[TiO 2 ]]> <![CDATA[V 2 THE 5 ]]> MgO <![CDATA[Al 2 THE 3 ]]> CaO <![CDATA[SiO 2 ]]> Mass ratio / % 56.902 10.242 0.714 3.066 3.334 0.493 2.806

[0101] The above vanadium-titanium iron ore is used to produce pellets, and no other iron-containing raw materials are added in 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[TiO 2 ]]> <![CDATA[V 2 THE 5 ]]> MgO <![CDATA[Al 2 THE 3 ]]> CaO <![CDATA[SiO 2 ]]> Mass ratio / % 54.915 9.703 0.685 2.968 3.38 0.668 3.546

[0104] Due to the insufficient output of pelletizing line, in order to obtain better metallurgical properties of sintered ore, the TiO 2 For vanadium-titanium iron ore with a content of >8%, it is recommended that the proportion of pellets in the blast furnace iron material is >50%, for example: the ore ratio of the blast furnace is 60% pellets and 40% sintered ore, without adding agglomerates. Control the TiO content of sintered ore 2 The content is less than 3.5, in order to obtain better metallurgical properties of sintered ore. For this reason, vanadium-titanium iron ore is used for pellet production first, and the rest is used for sintering production. The iron raw materials for sintering production are partly vanadium-titanium iron ore and partly other iron ores. Due to the control of TiO 2 The content is less than 3.5, and the metallurgical properties of vanadium-titanium sintered ore can be greatly improved. There is no need to specially control the MgO content in the sintered ore, which saves the amount of high MgO flux added in the sintered ore production process, thereby reducing production costs. The composition of the sintered ore is shown in Table 6, and the proportion of vanadium-titanium iron ore in the blast furnace that can be obtained is greater than 75%.

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

[0106] Element TFe <![CDATA[SiO 2 ]]> CaO MgO <![CDATA[Al 2 THE 3 ]]> <![CDATA[TiO 2 ]]> <![CDATA[V 2 THE 5 ]]> 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 the drum strength of sintered ore after implementation was >76%; the low-temperature reduction differentiation rate of sintered ore improved from an average of 55% to an average of 26.1%, and the low-temperature reduction pulverization rate of sintered ore was <30% after implementation.

[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 R 2 <1.12.

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

[0110] Element <![CDATA[SiO 2 ]]> CaO MgO <![CDATA[Al 2 THE 3 ]]> <![CDATA[TiO 2 ]]> <![CDATA[V 2 THE 5 ]]> Mass ratio / % 24.824 26.195 8.565 14.065 23.571 0.290

[0111] According to the method for smelting high-proportion vanadium-titanium iron ore in an oxygen blast furnace (including thermal system, charging method and tuyere gas injection parameters) of the present invention, the actual results obtained are: the [V] content in the molten iron is 0.313%, the coke ratio is 270kg / t, the coal ratio is 100kg / t, and the distribution coefficient of vanadium element in molten iron and slag is [V] / (V 2 O 5 )=1.38>1.3, the titanium load of the comprehensive raw materials entering the furnace is 135kg / t, the slag (TiO 2 ) content reaches 23.57%, which is better than the current international leading level. Compared with the traditional blast furnace, the fuel and power cost used in the smelting method of the present invention is reduced by 57 yuan / ton of iron. Furthermore, since the price of vanadium-titanium iron ore is lower than that of ordinary iron ore, the cost of ore blending is reduced by 13 yuan / ton of iron. 2 Physical emissions decreased 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 in a certain place is shown in Table 8:

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

[0115] Element TFe <![CDATA[TiO 2 ]]> <![CDATA[V 2 THE 5 ]]> MgO <![CDATA[Al 2 THE 3 ]]> CaO <![CDATA[SiO 2 ]]> Mass ratio / % 62.92 4.13 0.81 2.9 3.1 0.5 2.9

[0116] The above vanadium-titanium iron ore is used to produce pellets. No other iron-containing raw materials are added in the ore blending process. Flux and binder are added in 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[TiO 2 ]]> <![CDATA[V 2 THE 5 ]]> MgO <![CDATA[Al 2 THE 3 ]]> CaO <![CDATA[SiO 2 ]]> Mass ratio / % 57.9 3.8 0.8 3.2 3.5 4.1 3.6

[0119] The proportion of blast furnace pellets in the blast furnace iron material is 100% pellets, no sintered ore and lump ore are added, and the proportion of vanadium-titanium iron ore in the blast furnace is 100%. The composition of the generated blast furnace slag is shown in Table 10:

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

[0121] Element <![CDATA[TiO 2 ]]> <![CDATA[V 2 THE 5 ]]> MgO <![CDATA[Al 2 THE 3 ]]> CaO <![CDATA[SiO 2 ]]> Mass ratio / % 16.5 0.32 12.2 14.5 19.1 16.8

[0122] According to the method for smelting high-proportion vanadium-titanium iron ore in an oxygen blast furnace (including thermal system, charging method and tuyere gas injection parameters) of the present invention, the actual results obtained are: the [V] content in the molten iron is 0.767%, the coke ratio is 260kg / t, the coal ratio is 90kg / t, and the distribution coefficient of vanadium element in molten iron and slag is [V] / (V 2 O 5 )=1.51>1.3. Compared with the traditional blast furnace, the fuel and power cost used in the smelting method of the present invention is reduced by 53 yuan / ton of iron. Furthermore, since 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 / ton. 2 Physical emissions decreased 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-titanium iron ore in a certain place is shown in Table 11:

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

[0126] Element TFe <![CDATA[TiO 2 ]]> <![CDATA[V 2 THE 5 ]]> MgO <![CDATA[Al 2 THE 3 ]]> CaO <![CDATA[SiO 2 ]]> Mass ratio / % 62.92 4.13 0.81 2.9 3.1 0.5 2.9

[0127] Due to the insufficient output of the pellet production line, the ore ratio of the blast furnace is 55% acidic pellets and 45% alkaline sintered ore, and no lump ore is added. The above vanadium-titanium iron ore is used to produce pellets. No other iron-containing raw materials and flux are added during the pelletizing process. Binders are added during the pelletizing process. The composition of the produced pellets is shown in Table 12:

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

[0129] Element TFe <![CDATA[TiO 2 ]]> <![CDATA[V 2 THE 5 ]]> MgO <![CDATA[Al 2 THE 3 ]]> CaO <![CDATA[SiO 2 ]]> Mass ratio / % 62.10 4.08 0.80 2.91 3.16 0.67 3.84

[0130] Vanadium-titanium iron ore is used for pelletizing first, and the rest is used for sintering. 2 The content is less than 3.5, in order to obtain better metallurgical properties of sintered ore. After balance, it can be obtained that when the proportion of vanadium-titanium iron ore in the iron raw material of sintering production is 100%, it can meet the requirements of sintered ore TiO 2Content <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 by Example 4 vanadium-titanium iron ore

[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[TiO 2 ]]> <![CDATA[V 2 THE 5 ]]> MgO <![CDATA[Al 2 THE 3 ]]> CaO <![CDATA[SiO 2 ]]> Mass ratio / % 16.5 0.32 12.2 14.5 19.1 16.8

[0136] According to the method for smelting high-proportion vanadium-titanium iron ore in an oxygen blast furnace (including thermal system, charging method and tuyere gas injection parameters) of the present invention, the actual results obtained are: the [V] content in the molten iron is 0.767%, the coke ratio is 260kg / t, the coal ratio is 90kg / t, and the distribution coefficient of vanadium element in molten iron and slag is [V] / (V 2 O 5 )=1.53>1.3. Compared with the traditional blast furnace, the fuel and power cost used in the smelting method of the present invention is reduced by 53 yuan / ton of iron. Furthermore, since 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 / ton. 2 Physical emissions decreased 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[H 2 ]]> CO <![CDATA[N 2 ]]> <![CDATA[CO 2 ]]> <![CDATA[CH 4 ]]> <![CDATA[C 2 H 2 ]]> <![CDATA[O 2 ]]> 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 reducing gas after coke oven gas reforming in Example 5

[0143] Element <![CDATA[H 2 ]]> CO <![CDATA[N 2 ]]> 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 amount of bosh gas is 1500m 3 / t.

[0145] Table 17: Composition of the Bosh Gas in Example 5

[0146] Element <![CDATA[H 2 ]]> CO <![CDATA[N 2 ]]> content / % 13.59 72.50 13.91

[0147] As the furnace gas rises, it reacts with the iron oxides in the furnace to generate metallic iron and H. 2 O、CO 2 When the gas reaches the furnace top, the composition of the gas at the furnace top is shown in Table 18 below. The gas volume at the furnace top is 1500m 3 / t.

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

[0149] Element <![CDATA[H 2 ]]> CO <![CDATA[N 2 ]]> <![CDATA[CO 2 ]]> <![CDATA[H 2 The]]> content / % 8.44 43.58 13.91 28.92 5.15

[0150] CO removal from top gas 2 , H 2 O. The composition of the purified gas after dust removal is shown in Table 19 below. The amount of purified gas is 989m 3 / t. Visible N 2 It is enriched in the purified gas. If part of it is not exported, N 2 After the next round or multiple rounds of recycling, the gas will be further enriched and rise to more than 25%. 3 55m in / t 3 / t of purified gas is delivered to other users, 934m 3 / t of purified coal gas is transported to the heating furnace for heating and then supplied to the blast furnace for recycling. 3 / t of purified gas cannot meet the needs of blast furnace kinetic energy, so a part of coke oven gas reforming gas is added. The role of supplementing coke oven gas reforming gas is twofold: one is to increase the blast kinetic energy and ensure the activity of the furnace, and the other is to dilute the N 2 content.

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

[0152] Element <![CDATA[H 2 ]]> CO <![CDATA[N 2 ]]> content / % 12.81 66.10 21.09

[0153] 934m 3 / t of purified gas enters the next round of recycling process: in the gas heating furnace, N 2 The purified gas with 21.09% N 2The reformed gas with a content of 4.7% coke oven gas is mixed into high-temperature reducing gas and sent into the furnace, and then mixed with the CO produced by the combustion and reduction reaction of carbon in the furnace to form N 2 The content of 13.91% of the furnace gas is repeated over and over again. 2 The content is stable at around 13.91%.

[0154] In summary, the smelting method of the present invention achieves a blast furnace vanadium-titanium iron ore ratio greater than 60%, and TiO 2 The mass fraction of CO is greater than 15% and less than 45%, 2 Emissions reduced by more than 30% from blast furnace smelting.

[0155] Although the specific implementation of the present invention is described in detail in conjunction with the drawings, it should not be understood as limiting the scope of protection of this patent. Within the scope described in 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, It is characterized in that The following steps are involved: The blast furnace uses pure oxygen injection, and pure oxygen, hot coal gas and coal powder are sprayed into the tuyere; iron and coke are added from the top of the furnace; the N 2 The volume percentage is less than 25%; CO removal from top gas 2 Post-recycling; 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 TiO in the pellets 2 The content 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 material fed into the blast furnace is greater than 30%; the TiO 2 Mass fraction <5%; TiO in blast furnace slag generated by smelting 2 The mass fraction of vanadium-titanium iron ore is greater than 15% and less than 45%, the proportion of vanadium-titanium iron ore in blast furnace is greater than 60%, and the proportion of CO in blast furnace is greater than 60%. 2 Emissions reduced by 30%.

2. A method for smelting high-proportion vanadium-titanium iron ore in an oxygen blast furnace as claimed in claim 1, Features: 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.

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

4. A method for smelting high-proportion vanadium-titanium iron ore in an oxygen blast furnace as claimed in claim 1, Features: The mass ratio of the blast furnace iron material to coke is 5.5-7.5:1, and the mass ratio of the 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.

5. A method for smelting high-proportion vanadium-titanium iron ore in an oxygen blast furnace as claimed in claim 1, Features: The distribution coefficient of vanadium in molten iron and slag during blast furnace smelting [V] / (V 2 O 5 )>1.

1.

6. A method for smelting high-proportion vanadium-titanium iron ore in an oxygen blast furnace as claimed in claim 1, Features: 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.

7. A method for smelting high-proportion vanadium-titanium iron ore in an oxygen blast furnace as claimed in claim 1, It is characterized in that The method for loading the iron material and the coke is as follows: at the height of the blast furnace charge surface, a horizontal cross section of the blast furnace is taken, the circle where the cross section is located is equally divided into 11 circular rings of equal area, and the circular rings are numbered in sequence from the inner ring to the outer ring, and the material distribution system is as follows: 60%-80% of the coke is distributed in the 9th to 11th rings and the 1st to 5th rings, 20%-40% of the coke is distributed in the 6th to 8th rings, 70%-90% of the iron material is distributed in the 4th to 10th rings, and 10%-30% of the iron material is distributed in the 1st to 3rd rings and the 11th ring.

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