Method for strengthening blast furnace smelting based on balance theory combustion temperature

Abstract

The invention relates to a method for strengthening blast furnace smelting based on equilibrium theory combustion temperature, which belongs to the technical field of blast furnace smelting, and comprises the following steps of: A, preparing materials according to the following steps: B, setting raw fuel and indexes, C, smelting under the following conditions, D, controlling in the smelting process as follows, E, obtaining low-silicon qualified pig iron with the following indexes after smelting, and E, obtaining low-silicon qualified pig iron with the following indexes after smelting. And F, verifying the blast furnace smelting fuel cost and the utilization coefficient as follows: if the fuel cost is continuously reduced and the blast furnace utilization coefficient is not lower than the range of the step E, continuing smelting. The problems that the blast furnace operation difficulty is increased, the blast furnace condition is unstable, the utilization coefficient is low and the fuel cost is high due to the fact that the injection pulverized coal resource is single, the cost is high and the theoretical combustion temperature of the injection mixed pulverized coal is inaccurately controlled in the existing blast furnace smelting are solved. The utilization degree of blast furnace injection fuel resources with high cost performance is expanded, the smelting index is improved by utilizing the combustion temperature balance calculation of the mixed injection fuel theory, and the effects of increasing the yield and reducing the cost are achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of blast furnace smelting, and particularly relates to a theoretical combustion temperature calculation model construction and a blast furnace smelting method based on theoretical combustion temperature calculation balance for strengthening smelting of a blast furnace with multi-coal injection and multi-ore smelting. BACKGROUND

[0002] It is important to enhance the core competitiveness of steel enterprises to adapt to local conditions, maximize and stably use local or nearby regional iron ore resources and blast furnace fuel resources, develop blast furnace injection fuel resources, optimize blast furnace injection fuel structure and operation parameters, increase the yield of different volume blast furnace single molten iron (utilization coefficient), and reduce the cost of blast furnace fuel, so as to ultimately achieve the purpose of increasing production and reducing cost of blast furnace smelting. As the region where the inventors are located, Yunnan Province, not only lacks high-quality iron ore and high-quality coke, but also lacks anthracite and bituminous coal for blast furnace injection. However, the reserves of lignite are very rich. Compared with other coal types, lignite is relatively stable in chemical composition and quality, has high hydrogen and combustible volatile matter and low ash content, has a high CaO / SiO2 value of ash, and has a price of only about 1 / 3 of the current prices of anthracite, lean coal, and bituminous coal commonly used in blast furnaces. Therefore, on the basis of using high-alkali vanadium-titanium sintered ore, high-alkali ordinary sintered ore, low-silicon vanadium-titanium acidic oxidized pellet ore, and high-silicon acidic oxidized pellet ore made by sintering local or nearby regional titanium-containing iron ore concentrate resources in Yunnan Province at a large scale and in a high proportion, and using high-ash, high-sulfur, and low-fixed carbon content coke in Yunnan Province, a new method for low-grade strengthening smelting of a blast furnace using mixed injection of lignite resources is developed. The low-cost and cost-effective local lignite resources in Yunnan are used as blast furnace injection fuel to produce qualified pig iron with high strength and stability for a long period, and further optimization and control of gas parameters, improvement of blast furnace utilization coefficient, and reduction of blast furnace injection fuel cost, become one of the important ways to enhance the competitiveness of the ironmaking process in inland areas.

[0003] Due to the low grade, high content of gangue impurities such as w(SiO2) and w(Al2O3), and harmful elements such as potassium, sodium, lead, and zinc in the local and surrounding iron ore resources of Yunnan Province, large-scale application of this technology results in: large slag production, large fluctuations in the silicon content of pig iron and slag basicity, and the harmful elements' impact on the smelting process and blast furnace type. It is also difficult to balance the w([Si]) and w([S]) content with physical heat in pig iron, easily leading to fluctuations in furnace conditions and making it difficult to establish effective and stable technical parameters during operation. Furthermore, the low-grade (TFe < 56%) intensified smelting in Yunnan Province, due to its slag-forming characteristics, is not conducive to increasing the coal ratio. The low coal ratio makes it difficult for the blast furnace to accept higher blast temperatures and oxygen enrichment rates, resulting in difficulties in balancing the theoretical combustion temperature. In practice, there are even cases where humidified blast is used to balance the theoretical combustion temperature. More importantly, with the large-scale application of resources (vanadium-titanium magnetite) in the surrounding areas of Yunnan Province, once vanadium and titanium elements exceed a certain load, high-melting-point TiC, TiN, and Ti(C, N) readily form suspended in the slag and iron at high temperatures. This deteriorates slag fluidity and the smelting process within the furnace. Consequently, the intensified smelting of vanadium-titanium magnetite often requires a higher oxygen potential, which further exacerbates the contradiction between raw material resources and intensified smelting parameters. This has become a bottleneck restricting the large-scale and efficient use of local and surrounding raw material resources in medium and large blast furnaces.

[0004] For the control and optimization of blast furnace smelting processes and operating procedures, the actual theoretical combustion temperature is an extremely important control parameter and a key to the harmony of various smelting parameters. Existing technologies, such as calculating the actual theoretical combustion temperature and using this calculated value to balance pulverized coal injection ratio and oxygen enrichment for intensified blast furnace smelting, while establishing a calculation model for the actual theoretical combustion temperature of injected fuels and quickly calculating the changes in the actual theoretical combustion temperature, furnace gas volume, and direct reduction degree after different fuel injections, fail to reflect the quantitative impact of changes in hydrogen content and decomposition heat caused by alterations in the structure of injected fuels on the calculated actual theoretical combustion temperature. Furthermore, they lack the advantages of quantitative balancing based on changes in the calculated actual theoretical combustion temperature and ease of operation. This inaccuracy in the actual theoretical combustion temperature and mismatch with operating parameters is highly detrimental to the timely and accurate implementation of blast furnace operating procedures, furnace condition stability, and the exploitation of intensification potential. Therefore, it is of great significance to develop new methods that enable large-scale utilization of different fuel resources such as lignite for mixed pulverized coal injection, enhance blast furnace smelting, and achieve higher blast furnace utilization coefficients and lower fuel costs. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and, based on the construction of a theoretical combustion temperature calculation model for blast furnaces, provide a method for enhancing blast furnace smelting based on equilibrium theoretical combustion temperature, so as to obtain qualified molten iron with high utilization coefficient and low fuel cost.

[0006] To achieve the above objectives, the present invention provides a technical solution: a method for enhancing blast furnace smelting based on equilibrium theory and combustion temperature, characterized by comprising the following steps:

[0007] A. Prepare materials as follows:

[0008] The ore mass percentages are as follows:

[0009]

[0010] The sum of the above four types of minerals is 100%;

[0011] The coke is conventional high-ash coke and small-particle coke;

[0012] The pulverized coal mixture for injection is obtained by mixing anthracite, bituminous coal, and lignite with different carbon and hydrogen contents in any proportion;

[0013] B. The raw materials and specifications are set, with a volume of 1080m³. 3 ~2500m 3 The blast furnace is configured as follows:

[0014] Ore weight: 20-35 kg / m 3 ;

[0015] Dry basis coke batch weight: 7500~14000kg / batch, including dry basis small particle coke batch weight: 500~1000kg / batch;

[0016] Dry basis coke load: 4.20~5.00;

[0017] Pulverized coal injection rate at the tuyere: 19.0~60.0t / h;

[0018] Theoretical combustion temperature: (2250~2450℃)±5℃;

[0019] For a mixed coal powder obtained by any proportion of anthracite, bituminous coal and lignite, under the condition of maintaining the dry basis coke batch weight, the hourly injection rate of the mixed coal powder after the change of the coal powder mixing ratio is determined according to the carbon and hydrogen content in the selected mixed coal powder, and the ignition point, grindability index, average combustion rate and maximum combustion rate of the mixed coal powder are verified.

[0020] C. Smelting shall be carried out under the following conditions: hot blast pressure: 0.30~0.45MPa, pressure difference: 0.5 times hot blast pressure ±0.005MPa, hot blast temperature: 1180~1250℃, furnace air volume: 3000~6500m³ 3 / min, oxygen enrichment in the blower: 9000~30000m³ 3 / h, pulverized coal injection ratio: 110~180kg / t iron, injection rate: 21.0~35.0%; material rate: 7.5~10.5 batches; furnace hearth gas composition control: CO: 35~45%, H2: 3.0~10.0%, N2: 50%~60%;

[0021] During the smelting process, the theoretical material rate and the actual material rate are verified.

[0022] During the smelting process, the maximum blast temperature is fixed, and the actual theoretical combustion temperature is calculated. This actual theoretical combustion temperature remains balanced and stable within a certain range, and the balanced and stable actual theoretical combustion temperature is used as the basis for adjusting the injection of mixed pulverized coal and the oxygen enrichment.

[0023] D. The following controls shall be implemented during the smelting process:

[0024] The content of sintered ore and pellet powder fed into the furnace is <1.0%;

[0025] The slag contains: magnesium oxide 7.5%–11.0%, titanium oxide 3.0%–17.0%, aluminum oxide 10.5%–13.5%, magnesium-aluminum ratio 0.70–0.98, and slag basicity 1.05–1.25.

[0026] The furnace top temperature is 100–260℃, the hot air temperature is 1180–1250℃, the oxygen enrichment rate is 3.5–7.0%, and the air permeability index is 15000–30000 m³. 3 / min.MPa, furnace gas volume 4000~8000m³ 3 / min, furnace gas development index 79.0~83.0m / min, permeability resistance coefficient 3.5~8.0;

[0027] E. Low-silicon qualified pig iron with the following indicators is obtained after smelting;

[0028] For 1080m 3 The blast furnace has an overall ore grade of 53.5%–54.5% and a blast furnace utilization coefficient of 3.65–3.85 t / m³. 3 .d, injection ratio 120-150 kg / t iron;

[0029] For 2500m 3 The blast furnace has an overall ore grade of 55.8%–56.8% and a blast furnace utilization coefficient of 2.75–3.10 t / m³. 3 .d, injection ratio 150-180 kg / t iron;

[0030] F. Verify the blast furnace smelting fuel cost and utilization coefficient as follows: If the fuel cost continues to decrease and the blast furnace utilization coefficient is not lower than the range in step E, then continue smelting.

[0031] Furthermore, the chemical composition mass percentage of each raw material is as follows:

[0032] The chemical composition (mass percentage) of the high-basicity sinter is as follows: TFe: 52.0–54.0%, FeO: 8.00–9.00%, SiO2: 5.0–6.5%, CaO: 12.0–13.5%, MgO: 2.60–3.00%, TiO2: 0.15–1.50%, V2O5: 0.100–0.170%, S: 0.035–0.065%, Al2O3: 2.00–2.30%, MnO: 0.10–0.30%, with the balance being unavoidable impurities; the high-basicity sinter drum index is 78.0%–80.0%, and the average particle size is 20–50 mm.

[0033] The chemical composition (mass percentage) of acidic oxidized vanadium-titanium pellets is as follows: TFe: 53.5–58.0%, FeO: 1.30–2.50%, SiO2: 4.50–5.50%, CaO: 0.50–1.50%, MgO: 2.35–2.75%, TiO2: 6.0–11.0%, V2O5: 0.50–0.95%, S: 0.008–0.015%, Al2O3: 2.50–3.00%, MnO: 0.23–0.30%, with the balance being unavoidable impurities; the particle size of the acidic oxidized vanadium-titanium pellets is 6 mm–16 mm, and the compressive strength is >2200 N / particle;

[0034] The chemical composition (mass percentage) of acidic oxidizing high-silica ordinary pellets is as follows: TFe: 58.0–59.5%, FeO: 1.10–1.50%, SiO2: 6.50–7.00%, CaO: 0.50–1.50%, MgO: 2.00–2.50%, TiO2: 0.59–1.50%, V2O5: 0.50–0.95%, S: 0.01–0.025%, Al2O3: 2.50–3.00%, MnO: 0.20–0.30%, with the balance being unavoidable impurities; the particle size of the acidic oxidizing high-silica ordinary pellets is 6 mm–16 mm, and the compressive strength is >2200 N / particle;

[0035] The chemical composition (mass percentage) of natural low-silicon common lump ore is as follows: TFe: 64.0–66.0%, SiO2: 2.5–4.0%, CaO: 0.025–0.055%, MgO: 0.005–0.025%, S: 0.010–0.020%, Al2O3: 1.00–1.10%, MnO: 0.15–0.25%, TiO2: 0.005–0.015%, V2O5: 0.025–0.035%, with the balance being unavoidable impurities; the particle size of the natural low-silicon common lump ore is 25 mm–45 mm, and the powder content in the furnace is <1.50%;

[0036] The chemical composition of coke by mass percentage is as follows: Moisture: 0.8-4.2%, C: 83.0-86.0%, Ash: 12.5-13.8%, S: 0.50-0.65%, balance being unavoidable impurities; M40: 85.0-89.0%, M10: 4.10-5.10%; CRI: 22.0-26.0%, CSR: 63.0-68.0%;

[0037] The mass percentage composition of coke ash is as follows: SiO2: 53.0-54.0%, CaO: 2.0-2.5%, MgO: 0.10-0.30%, Al2O3: 23.0-25.0%, with the balance being unavoidable impurities;

[0038] The pulverized coal mixture is obtained by mixing anthracite, bituminous coal, and lignite with different carbon and hydrogen contents in any proportion, wherein:

[0039] The chemical composition of the anthracite, by mass percentage, is as follows: Moisture: 0.5–1.5%, Volatile matter (V): 7.0–9.0%, Ash: 9.5–12.0%, Water of crystallization: 0.8–1.2%; Combustible and volatile elements include: Total carbon content 78.0–80.0%, Hydrogen content 2.0–3.0%, Oxygen content 3.5%–5.5%, Nitrogen content 1.0%–3.0%, Sulfur content 0.55–0.70%, with the balance being ash; The ash composition of the pulverized coal, by mass percentage, is as follows: SiO2: 47.0–48.0%, CaO: 5.0–5.5%, MgO: 2.0–2.5%, Al2O3: 23.0–25.0%, TiO2: 1.5–1.7%, with the balance being unavoidable impurities; The calorific value of the anthracite is 1050–1100 KJ / kg;

[0040] The chemical composition of bituminous coal by mass percentage is as follows: moisture: 0.5-1.5%, volatile matter (V): 13.0-15.0%, ash (Ash): 10.0-13.0%, water of crystallization: 1.0-2.0%; combustible and volatile elements include: total carbon content 74.0-76.0%, hydrogen content 4.0-6.0%, oxygen content 4.5%-6.5%, nitrogen content 2.0%-4.0%, sulfur content 0.55-0.70%, with the balance being ash; wherein, the ash composition of pulverized coal by mass percentage includes: SiO2: 47.0-48.0%, CaO: 5.0-5.5%, MgO: 2.0-2.5%, Al2O3: 23.0-25.0%, TiO2: 1.5-1.7%, with the balance being unavoidable impurities; the decomposition heat of the bituminous coal is 1900-2100 KJ / kg;

[0041] The chemical composition of lignite by mass percentage includes: moisture: 0.5-1.5%, volatile matter (V): 30.0-40.0%, ash (Ash): 20.0-30.0%, and water of crystallization: 3.0-10.0%; combustible and volatile elements include: total carbon content 40.0-50.0%, hydrogen content 6.0-8.0%, oxygen content 25.0%-35.0%, nitrogen content 2.0%-4.0%, sulfur content 0.80-1.20%, with the balance being ash; wherein, the ash composition of pulverized coal by mass percentage includes: SiO2: 8.0-10.0%, CaO: 40.0-45.0%, MgO: 2.0-3.5%, Al2O3: 7.0-8.5%, TiO2: 0.5-1.0%, with the balance being unavoidable impurities; the heat of decomposition of the lignite is 2750-2950 KJ / kg.

[0042] Furthermore, in step B, the hourly injection rate (M) of the mixed pulverized coal after the change in the pulverized coal mixing ratio is... h The formula for determining this is:

[0043]

[0044] Where: M h The hourly pulverized coal injection rate after changes in the pulverized coal mixing ratio, unit: kg·h -1 M j The hourly base pulverized coal injection rate before changes in the pulverized coal mixing ratio, unit: kg·h -1 ;w(C) j The carbon content of the pulverized coal before the change in the pulverized coal mixing ratio is expressed in % (w(H)). j The hydrogen content of the pulverized coal before the change in the pulverized coal mixing ratio is expressed in % (w(C)). h The carbon content of pulverized coal after changes in the mixing ratio is expressed in % (w(H)). hThe hydrogen content of pulverized coal after changes in the pulverized coal mixing ratio is expressed in %;

[0045] The ignition point, grindability index, average combustion rate, and maximum combustion rate of the mixed pulverized coal are verified as follows: the mixed pulverized coal must have an ignition point >280℃, a grindability index of 55%–65%, and an average combustion rate (dW / dt). mean 4.0~6.0%·min -1 Maximum combustion rate (dW / dt) mean 6.0~8.5%·min -1 If the verification is successful, smelting can continue.

[0046] Furthermore, in step C, the theoretical material rate and the actual material rate are verified as follows: if |theoretical material rate - actual material rate| < 0.5 batches / hour, or the absolute value of the difference between the theoretical material rate and the actual material rate for two consecutive hours is < 1 batch / hour, the verification is passed and smelting continues.

[0047] In step C, the air temperature is controlled to be the highest value that can be stably reached during the smelting process. The actual theoretical combustion temperature is calculated as follows:

[0048] C1) Calculate the hearth gas volume, which is the sum of the volume of CO, H2, and N2 components in the hearth gas. The percentage of CO, H2, and N2 components in the blast furnace hearth gas is the ratio of the volume of each component to the total hearth gas volume. The H2 content in the hearth gas increases with the increase of hydrogen content in the mixed pulverized coal, which increases the hearth gas volume and decreases the actual theoretical combustion temperature.

[0049] The volumetric composition of CO, H2, and N2 in the blast furnace hearth gas is calculated using the following formula:

[0050] The volume of H2 in the blast furnace hearth gas is calculated using the following formula:

[0051]

[0052] In the formula: The volume of H2 in the hearth gas produced to produce 1 ton of iron, in cubic meters. 3 ·t -1 V B The amount of air required to produce 1 ton of iron, in meters. 3 ·t -1 ; The increase in oxygen content in the air volume consumed to produce 1 ton of iron, in m³. 3 ·t -1 M h The ratio of pulverized coal to pulverized coal is given in kg·t. -1 ;Φ mCombustion rate of mixed pulverized coal, unit: %; b s The amount of air transported for conveying the mixed pulverized coal, in cubic meters (m³). 3 ·kg -1 ; The relative humidity of the air in the blower, in %; Hydrogen content of mixed pulverized coal, unit: %; The physical moisture content of the mixed pulverized coal is expressed in %; where:

[0053] The calculation formula is as follows:

[0054]

[0055] In the formula: The oxygen content in the blower air, in %; The relative humidity of the atmosphere in the blower, in %; V B The amount of air required to produce 1 ton of iron, in meters. 3 ·t -1 ;

[0056] Oxygen content in the blower The calculation formula is as follows:

[0057]

[0058] In the formula: The relative humidity of the air in the blower, in %; Oxygen enrichment rate of the blower, unit: %;

[0059] Blower oxygen enrichment rate The calculation formula is as follows:

[0060]

[0061] In the formula: The hourly oxygen enrichment in the blower air, unit: m³ 3 ·h -1 V f The actual blast volume injected into the blast furnace, in m³. 3 ·min -1 ;

[0062] The formula for calculating the volume of N2 in the blast furnace hearth gas is as follows:

[0063]

[0064] In the formula: The volume of N2 in the hearth gas produced to produce 1 ton of iron, in cubic meters. 3 ·t -1 VB The amount of air required to produce 1 ton of iron, in meters. 3 ·t -1 ; The increase in oxygen content in the air volume consumed to produce 1 ton of iron, in m³. 3 ·t -1 M h The ratio of pulverized coal to pulverized coal is given in kg·t. -1 b s The amount of air transported for conveying the mixed pulverized coal, in cubic meters (m³). 3 ·kg -1 ; The relative humidity of the air in the blower, in %; Oxygen enrichment rate of the blower, unit: %; Nitrogen content in oxygen-enriched blower air, unit: %; Nitrogen content in mixed pulverized coal, unit: %; Φ MC Combustion rate of mixed pulverized coal before the tuyeres, unit: %;

[0065] The formula for calculating the volume of CO in the blast furnace hearth gas is as follows:

[0066] V CO =(K J ×C J ×φ JC / 10000+M h ×C M ×φ MC / 10000) / 12×22.4 (6)

[0067] In the formula: V CO The volume of CO in the hearth gas produced to produce 1 ton of iron, in cubic meters. 3 ·t -1 ;K J The amount of dry coke consumed to produce 1 ton of iron, in kg·t -1 C J Carbon content in dry coke, unit: %; Φ JC Coke combustion rate before the tuyeres; unit: %; M h The ratio of pulverized coal to pulverized coal is given in kg·t. -1 C M Carbon content in mixed pulverized coal, unit: %; Φ MC Combustion rate of mixed pulverized coal before the tuyeres, in %;

[0068] During the smelting process, the actual theoretical combustion temperature is calculated to remain balanced and stable within a certain range. The balanced and stable actual theoretical combustion temperature is used as the basis for adjusting the injection of mixed coal powder and the oxygen enrichment. The hourly injection rate of mixed coal powder is calculated according to formula (1). The oxygen enrichment is directly input as the hourly oxygen enrichment flow rate until the calculated actual theoretical combustion temperature meets the set theoretical combustion temperature (2250~2450℃) ±5℃.

[0069] C2), the actual theoretical combustion temperature is calculated as follows:

[0070] The control process for the theoretical combustion temperature is as follows: basic data → establishment of the theoretical combustion temperature calculation model → input of mixed pulverized coal ratio → input of hourly injection rate of mixed pulverized coal calculated by equation (1) → input of arbitrary hourly oxygen enrichment → composition of furnace gas → thermal balance of tuyeres area → theoretical combustion temperature → theoretical analysis; where:

[0071] The basic data includes: raw material composition, grindability and combustibility of mixed coal powder, decomposition endothermic data, etc.

[0072] The actual theoretical combustion temperature (T) L The calculation model for ) is as follows:

[0073]

[0074] In the formula: T L Q represents the theoretical combustion temperature during intensified smelting using pulverized coal injection, in °C. C The heat released when carbon burns to produce CO in front of the vent, measured in kJ·t. -1 Q RF The amount of hot air blown in and the physical heat it carries is measured in kJ·t. -1 Q HH The physical heat introduced by the carrier gas during the injection of mixed pulverized coal, in kJ·t. -1 Q R The sensible heat brought in by coke entering the combustion zone, unit: kJ·t -1 Q X1 The heat absorbed by the decomposition of moisture in the blower air is expressed in kJ·t. -1 Q X2 The decomposition endothermic reaction of mixed pulverized coal injected during the blast furnace for smelting 1 ton of iron is given in kJ·t. -1 V g The volume of hearth gas produced in the smelting of 1 ton of iron, in m³. 3 ·t -1 c p t To generate hearth gas at T L Specific heat capacity at temperature, unit: kJ·(m³) 3·℃) -1 ;

[0075] in:

[0076]

[0077] In the formula: Q X1 The heat absorbed by the decomposition of moisture in the blower air is expressed in kJ·t. -1 V B The amount of air required to produce 1 ton of iron, in meters. 3 ·t -1 ; The increase in oxygen content in the air volume consumed to produce 1 ton of iron, in m³. 3 ·t -1 b s The amount of air transported for conveying the mixed pulverized coal, in cubic meters (m³). 3 ·kg -1 M h The ratio of pulverized coal to pulverized coal is given in kg·t. -1 ; The relative humidity of the air in the blower, in %;

[0078] Q X2 =Q HM ×M h (9)

[0079] In the formula: Q HM The heat of decomposition per unit mass of mixed pulverized coal, unit: kJ·kg -1 M h The ratio of mixed pulverized coal injection is expressed in kg·t. -1 ;

[0080]

[0081] In the formula: The volume of H2 in the hearth gas produced to produce 1 ton of iron, in cubic meters. 3 ·t -1 V CO The volume of CO in the hearth gas produced to produce 1 ton of iron, in cubic meters. 3 ·t -1 ; The volume of N2 in the hearth gas produced to produce 1 ton of iron, in cubic meters. 3 ·t -1 ;

[0082] In formula (5), the remaining Q C Q RF Q HH Q R The parameter calculation formula is as follows:

[0083] Q C =9797×(K) J ×C J / 100×φ JC / 100+M h ×C M / 100×φ MC / 100) (11)

[0084] In the formula: Q C K represents the heat released when carbon burns to produce CO in front of the vent. J The amount of dry coke consumed to produce 1 ton of iron, in kg·t -1 C J Carbon content in dry coke, unit: %; Φ JC M represents the coke combustion rate before the tuyeres. h The ratio of pulverized coal to pulverized coal is given in kg·t. -1 C M Carbon content in mixed pulverized coal, unit: %; Φ MC Combustion rate of mixed pulverized coal before the tuyeres, unit: %.

[0085]

[0086] In the formula: Q RF To blow in hot air and bring in physical heat, V B The amount of air required to produce 1 ton of iron, in meters. 3 ·t -1 ; The increase in oxygen content in the air volume consumed to produce 1 ton of iron, in m³. 3 ·t -1 ;T F The hot air temperature is in °C.

[0087] Q HH =M h ×b s ×T M ×1.3084 (13)

[0088] In the formula: Q HH The physical heat introduced by the carrier gas during the injection of mixed pulverized coal; T M Carrier gas temperature, unit: °C; b s The amount of air transported for conveying the mixed pulverized coal, in cubic meters (m³). 3 ·kg-1; M h The pulverized coal injection ratio is expressed as a percentage (%).

[0089] Q R =2300×K J ×φ JC(14)

[0090] In the formula: Q R This refers to the sensible heat brought in by the coke as it enters the combustion zone; K J The amount of dry coke consumed to produce 1 ton of iron, in kg·t -1 ;Φ JC The coke combustion rate in front of the tuyere, in %;

[0091] Calculate the actual theoretical combustion temperature (T) L When, based on the obtained enthalpy value of the mixed gas in the furnace hearth The enthalpy of the mixed gas at different temperatures was calculated using conventional interpolation.

[0092] Calculate the actual theoretical combustion temperature (T) L The formula for calculating the enthalpy of the mixed gas in the furnace hearth at the given value is as follows:

[0093]

[0094] In the formula: The actual theoretical combustion temperature (T) during the intensified smelting of mixed pulverized coal. L The enthalpy of the mixed gas under the given conditions, in kJ·(m³) 3 ·t) -1 Q C The heat released when carbon burns to produce CO in front of the vent, measured in kJ·t. -1 Q RF The amount of hot air blown in and the physical heat it carries is measured in kJ·t. -1 Q HH The physical heat introduced by the mixed pulverized coal carrier gas, unit: kJ·t -1 Q R The sensible heat brought in by coke entering the combustion zone, unit: kJ·t -1 Q X1 The heat absorbed by the decomposition of moisture in the blower air is expressed in kJ·t. -1 Q X2 The decomposition endothermic heat of the mixed pulverized coal injected into the blast furnace required to smelt 1 ton of iron, unit: kJ·t -1 V g The volume of hearth gas produced for smelting 1 ton of iron, in m³. 3 ·t -1 .

[0095] Furthermore, in step D, the calculation of the furnace gas volume, furnace gas development index, and permeability resistance coefficient is obtained through conventional calculation formulas, as follows:

[0096] Furnace gas volume V BG The calculation formula is:

[0097]

[0098] In the formula: V F Actual air volume entering the furnace, unit: m³ 3 ·min -1 ; Oxygen enrichment, unit: m 3 ·h -1 W B Absolute humidity of the atmosphere during blower operation, unit: g·m -3 ;P C The injection rate of mixed pulverized coal is expressed in kg·h. -1 H represents the hydrogen content of pulverized coal, in %;

[0099] The formula for calculating the air permeability resistance coefficient K is:

[0100]

[0101] In the formula: P B The absolute pressure of the blower is 10 kPa; P T The absolute pressure at the furnace top is 10 kPa; V BG This refers to the volume of gas in the furnace belly, in cubic meters. 3 ·t -1 ;

[0102] Furnace gas development index x BG The calculation formula is:

[0103]

[0104] In the formula: d is the furnace hearth diameter, in meters; V BG This refers to the volume of gas in the furnace belly, in cubic meters. 3 ·t -1 .

[0105] Furthermore, in step F:

[0106] When verifying the blast furnace utilization coefficient of blast furnaces with different volumes, if the verification conditions are not met, the reasons should be investigated and the parameters adjusted.

[0107] When verifying fuel costs, if the verification conditions are not met, the reason is investigated; if fuel costs continue to decrease and the blast furnace utilization coefficient is not lower than the range of the aforementioned steps, smelting continues.

[0108] This invention utilizes low-grade, high-basicity ordinary (vanadium-titanium) sinter, acidic oxidizing ordinary (vanadium-titanium) pellets, and coke with high ash and sulfur content to scal-up inject mixed coal powder of anthracite, bituminous coal, and lignite with varying carbon and hydrogen contents in arbitrary proportions. This leverages the high hydrogen content and combustible volatile matter content of lignite. On one hand, the increased hydrogen produced by lignite decomposition enhances the penetration of reducing gases, improving the smelting reduction process in the blast furnace and activating the hearth. On the other hand, by utilizing the high CaO and low SiO2 values ​​of lignite ash, not only is slag volume reduced under the same conditions, but it also allows for the use of more acidic, emission-reducing, environmentally friendly, and lower-cost pellets with better reducibility under the same basicity of the sinter. Furthermore, lignite contains higher levels of crystal water and hydrogen compounds, requiring higher temperatures for decomposition. This complements the challenge of balancing the theoretical combustion temperature during intensified smelting of low-grade ores. Therefore, developing a blast furnace intensified smelting method based on the construction of a new model of blast furnace theoretical combustion temperature and the balance of its calculated values, using lignite mixed injection, has become one of the important ways to reduce fuel costs, improve utilization coefficients, and enhance the competitiveness of ironmaking processes in inland areas through intensified smelting of low-grade ore in blast furnaces.

[0109] This invention takes the construction of a new theoretical combustion temperature calculation model as its starting point, incorporating important related factors such as hydrogen content and heat of decomposition in the injected mixed fuel into the calculation model. This overcomes the shortcomings of traditional theoretical combustion temperature calculation models, which cannot reflect the quantitative impact of different hydrogen content and heat of decomposition of injected fuel on the calculated values. Starting with stabilizing a suitable theoretical combustion temperature value (within a set range) under specific conditions, the process is simple and requires no complex calculations. Only the carbon and hydrogen content of the blast furnace mixed pulverized coal needs to be input to obtain the hourly injection rate of the mixed pulverized coal after composition changes. Only the actual hourly oxygen enrichment needs to be continuously input (until the value calculated by the new theoretical combustion temperature calculation model constructed according to this invention reaches the predetermined theoretical combustion temperature value (±5℃)). Simultaneously, based on a series of given formulas, the invention automatically outputs relevant parameters such as the injection rate of the mixed pulverized coal, the hearth gas volume and composition after changes in oxygen enrichment, and the furnace gas development index. By controlling the various parameters of different blast furnace volumes according to the control range set by this invention, the beneficial effects of improving the blast furnace utilization coefficient, reducing fuel costs, and thus reducing the cost of molten iron production can be achieved. Ultimately, a new method was developed to achieve higher utilization coefficients, lower fuel costs, and stable long-term operation of the blast furnace under low-grade intensified smelting conditions by using mixed injection of different fuel resources such as lignite on a certain scale. This forms a new economical blast furnace smelting method under low-grade intensified smelting conditions. Furthermore, the operation process is extremely convenient.

[0110] The smelting method provided by this invention uses low-grade, high-basicity ordinary (vanadium-titanium) sinter, acidic oxidizing ordinary (vanadium-titanium) pellets, and low-silicon ordinary natural lump ore as raw materials, and uses high-ash coke and coal powder made of anthracite, bituminous coal, and lignite in any proportion as reducing agents to produce low-cost qualified pig iron.

[0111] The low-silicon, high-alkalinity vanadium-titanium sintered ore of the present invention is sintered using the technical solution of application number 201811369753.4.

[0112] The low-silica oxidizing vanadium-titanium pellets of the present invention are produced by pelletizing mainly Panzhihua vanadium-titanium magnetite concentrate through a vertical shaft furnace pelletizing process. The pellets with a particle size of 6mm to 16mm are obtained by screening with a 16mm screen and a 6mm screen to remove the >16mm and <6mm portions. The powder is then removed by a double-layer high-efficiency vibrating screen with an upper 6mm and a lower 4mm.

[0113] The acidic oxidizing ordinary pellets described in this invention are produced by refining pellets mainly from Yunnan Dahongshan high-silicon iron concentrate through a vertical furnace chain grate-rotary kiln process. The pellets with a particle size of 6mm to 16mm are then sieved with 16mm and 6mm screens to remove the >16mm and <6mm portions, and then the powder is removed by a double-layer high-efficiency vibrating screen with an upper 6mm and a lower 4mm.

[0114] The natural low-silica common lump ore described in this invention is purchased externally, and then the portion >40mm is removed by screening with a 40mm screen and the portion <20mm is removed by screening with a 20mm screen to obtain lump ore with a particle size of 20mm to 40mm. Then, the powder is removed by screening with a single-layer 5mm high-efficiency vibrating screen.

[0115] In step A of this invention, the coke used is coke with high ash and sulfur content; the amount of coke is fixed and not adjusted in this invention.

[0116] In step A of this invention, the mixed pulverized coal injected into the blast furnace tuyeres is obtained by any proportion of anthracite, bituminous coal, and lignite with different carbon and hydrogen contents.

[0117] In step B of this invention, the ignition point and grindability index of the mixed pulverized coal refer to the Hardgrove Grindability Index (HGI) of the pulverized coal; the average combustion rate refers to the average combustion speed of the mixed pulverized coal under blast furnace injection conditions, expressed as (dW / dt). mean Maximum combustion rate refers to the fastest combustion speed that the mixed pulverized coal can achieve under blast furnace injection conditions, expressed as (dW / dt). mean express.

[0118] In step B of this invention, the actual theoretical combustion temperature refers to the calculated value obtained from the theoretical combustion temperature calculation model constructed according to this invention.

[0119] In step C of this invention, the pulverized coal injection ratio is calculated by the hourly injection amount after the change of the mixed pulverized coal ratio obtained by the calculation formula (1) constructed according to this invention; the theoretical material velocity is calculated based on the actual fuel composition, air volume, hourly oxygen enrichment, and hourly injection fuel amount.

[0120] In step E of this invention, the low-silicon qualified pig iron with the following indicators obtained after smelting is produced by slag tapping and iron tapping in a parallel tapping mode. Specifically, this means that two tapping holes tap iron simultaneously for 5 to 10 minutes; that is, 5 to 10 minutes before the previous tapping hole is sealed, the next tapping hole has already been opened and iron is being tapped.

[0121] In step F of this invention, the fuel cost refers to the value of the mixed pulverized coal injection ratio multiplied by the unit price and proportion of each pulverized coal.

[0122] Compared with the prior art, the beneficial effects of this invention are as follows:

[0123] This invention is based on the fundamental theory of blast furnace ironmaking and smelting, combined with the actual chemical composition of raw materials and fuels and smelting parameters of the blast furnace. Based on the actual theoretical combustion temperature calculation model constructed in this invention, a corresponding method for enhancing blast furnace smelting is developed. This method establishes a new matching relationship between fuel composition, operating parameters, technical and economic indicators, and fuel costs. It enables the production of low-cost pig iron using a blend of low-grade, high-basicity ordinary (vanadium-titanium) sinter, acidic oxidizing ordinary (vanadium-titanium) pellets, high-ash coke, and cost-effective local lignite, as well as local and surrounding resources. Furthermore, it aims to further improve the blast furnace smelting utilization coefficient and reduce blast furnace injection fuel costs under the same grade conditions, thereby reducing the cost of molten iron production and effectively increasing output and reducing pig iron smelting costs, ultimately enhancing the competitiveness of ironmaking.

[0124] This invention addresses the problems of existing blast furnace smelting, such as high cost due to the single source of pulverized coal, low pulverized coal injection ratio, and increased blast furnace operation difficulty, difficulty in balancing smelting parameters, unstable blast furnace conditions, low utilization coefficient, and high fuel costs caused by inaccurate control of theoretical combustion temperature for mixed pulverized coal injection. Furthermore, it overcomes the problems of high dependence on a single source of blast furnace injection fuel in my country's blast furnace ironmaking production, low correlation between the calculated methods and values ​​of theoretical combustion temperature and the controlled blast furnace intensification smelting parameters and the type of injection fuel, and difficulty in accurately matching smelting parameters. Under certain conditions, it achieves the goal of expanding the utilization of cost-effective blast furnace injection fuel resources, and further improves the technical and economic indicators of smelting technology by using a method based on the calculation and balancing of theoretical combustion temperature of mixed injection fuels, achieving increased production and reduced costs. The theoretical combustion temperature calculation method involved in this invention is applicable not only to solid fuels with different hydrogen and carbon contents such as anthracite, bituminous coal, and lignite, but also to gaseous and liquid fuels with different hydrogen and carbon contents such as coke oven gas, natural gas, hydrogen, and heavy oil.

[0125] Under the current conditions of iron ore resources and transportation capacity, this method significantly reduces the reliance of blast furnace smelting on high-quality pulverized coal resources such as anthracite and bituminous coal, enabling large-scale, stable use of abundant, inexpensive, and high-hydrogen and combustible volatile organic compound (VOC) resources from Yunnan Province. It also provides a method to further enhance smelting intensity (increasing oxygen enrichment) by quantitatively balancing the theoretical combustion temperature value (calculated by the model constructed in this invention) as the hydrogen content of the injected fuel increases (here, increasing the proportion of lignite). By increasing the hydrogen content of the injected pulverized coal, the combustion efficiency of the pulverized coal is improved. Quantitatively increasing the oxygen enrichment rate achieves accurate balance of the appropriate theoretical combustion temperature and effectively reduces the air consumption per ton of coke and coal in blast furnace smelting, thereby increasing blast furnace output (utilization coefficient). Furthermore, it improves the stability of the blast furnace conditions during intensified smelting. Ultimately, this results in increased output, reduced iron smelting costs, and an effective expansion of the range of pulverized coal resources that can be used in blast furnace smelting.

[0126] Compared with existing methods for intensified smelting using hydrogen-containing fuels (gaseous and solid fuels) injected into blast furnaces, this invention addresses the shortcomings of conventional methods. While existing methods analyze, correct, and supplement traditional theoretical combustion temperature calculation models when injecting different hydrogen-containing fuels (gaseous and solid fuels), they lack the ability to quantitatively adjust hourly coal quantity based on varying hydrogen and carbon content of the injected fuel, and to balance the pulverized coal injection ratio and oxygen enrichment rate based on model calculations. Furthermore, existing technologies fail to quantify the impact of changes in hydrogen content and decomposition heat caused by alterations in the blast furnace fuel structure on the theoretical combustion temperature, nor do they offer convenient operational support based on quantitatively balancing changes in the theoretical combustion temperature. This results in inaccuracies in the actual theoretical combustion temperature and mismatches in operational parameters, which are highly detrimental to the timely and accurate implementation of blast furnace operating procedures, furnace condition stability, and the exploitation of intensification potential. Therefore, based on the large-scale utilization of high-alkalinity ordinary (vanadium-titanium) sinter and acidic oxidizing ordinary (vanadium-titanium) pellets produced from high-cost-performance iron concentrate resources in Yunnan Province or surrounding areas, and the use of coke with higher ash content, sulfur content and lower fixed carbon content from Yunnan Province, this invention can utilize local lignite resources in Yunnan Province for large-scale mixed injection intensified smelting, and obtain a higher utilization coefficient and lower fuel cost.

[0127] This invention enables long-term, stable smelting of low-silicon qualified pig iron under conditions of low feed grade and high ash and sulfur content coke, using high-performance lignite fuel resources (lignite proportion within the range of 5% to 35%) with different blending ratios. For smaller blast furnaces, corresponding to a comprehensive feed grade of 53.5% to 54.5% (smelting from ordinary ore or vanadium-titanium ore), the blast furnace utilization coefficient is 3.65 to 3.85 t / (m³). 3.d), injection ratio 120-150 kg / tFe; for larger blast furnaces, corresponding to a comprehensive feed grade of 55.8%-56.8% (ordinary ore smelting), blast furnace utilization coefficient 2.75-3.10 t / (m³). 3 .d), with an injection ratio of 150-180 kg / tFe, the cost of injection fuel is reduced by 3.0 yuan / ton of iron to 33.0 yuan / ton of iron.

[0128] This invention addresses the problems of high cost and low pulverized coal ratio in existing blast furnace smelting processes due to the reliance on a single source of pulverized coal, and the increased operational difficulty, unstable furnace conditions, low utilization coefficient, and high fuel costs caused by inaccurate control of the theoretical combustion temperature of mixed pulverized coal. Furthermore, it overcomes the issues of high dependence on a single source of blast furnace fuel in my country's blast furnace ironmaking production, the low correlation between the calculated methods and values ​​of the theoretical combustion temperature and the controlled blast furnace intensification smelting parameters and the type of pulverized fuel, and the difficulty in accurately matching smelting parameters. Under certain conditions, it aims to expand the utilization of cost-effective pulverized fuel resources and further improve the technical and economic indicators of smelting by using a method based on the theoretical combustion temperature balance calculation of mixed pulverized fuels, achieving the goals of increased production and reduced costs. The theoretical combustion temperature calculation method involved in this invention is applicable not only to solid fuels with different hydrogen and carbon contents such as anthracite, bituminous coal, and lignite, but also to gaseous and liquid fuels with different hydrogen and carbon contents such as coke oven gas, natural gas, hydrogen, and heavy oil. Moreover, it is simple and convenient to operate. Detailed Implementation

[0129] The present invention will now be described in further detail with reference to the embodiments.

[0130] Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be construed as limiting the scope of the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed in accordance with the techniques or conditions described in the literature in the field or according to the product instructions. Materials or equipment whose manufacturers are not specified are all conventional products that can be obtained by purchase.

[0131] Examples 1-5

[0132] Examples 1-5 are all at 1080m 3 The smelting of vanadium-titanium ore in a blast furnace specifically includes the following steps:

[0133] A. Prepare materials as follows:

[0134] The ore mass percentages are as follows:

[0135]

[0136]

[0137] The sum of the above four types of minerals is 100%;

[0138] The coke is conventional high-ash coke and small-particle coke;

[0139] The blast furnace tuyeres are injected with mixed pulverized coal, which is obtained by mixing anthracite, bituminous coal and lignite in the proportions shown in Table 1.

[0140] Table 1. Mixing ratio of pulverized coal in Examples 1-5, %

[0141] Item Anthracite Bituminous coal Lignite Reference 100 0 0 Example 1 80 20 0 Example 2 70 20 10 Example 3 60 20 20 Example 4 60 10 30 Example 5 60 5 35

[0142] in:

[0143] The chemical composition of the high-alkalinity vanadium-titanium sinter, by mass percentage, includes: TFe 52.096%, FeO 8.97%, SiO2 6.14%, CaO 13.14%, MgO 2.85%, TiO2 1.23%, V2O5 0.145%, S 0.035%, Al2O3 2.29%, and MnO 0.199%. The ISO drum index is 78.22%, and the average particle size is 22.9 mm.

[0144] The chemical composition of the acidic oxidized low-titanium pellets, by mass percentage, includes: TFe 57.35%, FeO 1.33%, SiO2 4.51%, CaO 0.59%, MgO 2.35%, TiO2 6.56%, V2O5 0.595%, S 0.011%, Al2O3 2.77%, and MnO 0.27%. The particle size of the acidic oxidized low-titanium pellets is 6mm to 16mm, and the compressive strength is 2388N / pellet.

[0145] The chemical composition of the acidic oxidizing high-titanium pellets, by mass percentage, includes: TFe 53.5–58.0%, FeO 1.30–2.50%, SiO2 4.50–5.50%, CaO 0.50–1.50%, MgO 2.35–2.75%, TiO2 6.0–11.0%, V2O5 0.50–0.95%, S 0.008–0.015%, Al2O3 2.50–3.00%, MnO 0.23–0.30%, with the balance being unavoidable impurities; the particle size of the acidic oxidizing high-titanium pellets is 10 mm, and the compressive strength is 2316 N / particle;

[0146] The chemical composition of the natural low-silicon common lump ore, by mass percentage, includes: TFe 65.34%, SiO2 2.99%, CaO 0.035%, MgO 0.015%, S 0.012%, Al2O3 1.07%, MnO 0.19%, TiO2 0.011%, V2O5 0.028%; the particle size of the natural low-silicon common lump ore is 33mm, and the powder content in the furnace is 1.20%.

[0147] The chemical composition of the coke, by mass percentage, includes: moisture 2.8%, C 84.5%, Ash 13.19%, S 0.59%; M40 88.1%, M10 5.05%; CRI 25.7%, CSR 64.8%; wherein, the ash composition of the coke, by mass percentage, includes: SiO2 53.7%, CaO 2.33%, MgO 0.22%, Al2O3 24.5%;

[0148] The anthracite's chemical composition, by mass percentage, includes: moisture 0.8%, volatile matter (V) 7.32%, ash (A) 11.89%, and water of crystallization 0.99%. Combustible and volatile element analysis includes: total carbon content 79.0%, hydrogen content 2.50%, oxygen content 4.83%, nitrogen content 1.15%, and sulfur content 0.63%. The ash composition of the pulverized coal, by mass percentage, includes: SiO2 47.9%, CaO 5.35%, MgO 2.27%, Al2O3 24.5%, and TiO2 1.57%. The anthracite's calorific value is 1090 KJ / kg.

[0149] The chemical composition of the bituminous coal, by mass percentage, includes: moisture 0.8%, volatile matter 13.01%, ash 10.18%, and water of crystallization 1.01%. Combustible and volatile element analysis includes: total carbon content 75.0%, hydrogen content 4.5%, oxygen content 5.75%, nitrogen content 3.88%, sulfur content 0.69%, with the balance being ash; wherein, the ash composition of the pulverized coal, by mass percentage, includes: SiO2 47.7%, CaO 5.35%, MgO 2.25%, Al2O3 23.9%, and TiO2 1.67%. The calorific value of the bituminous coal is 1962 KJ / kg.

[0150] The chemical composition of the lignite, by mass percentage, includes: moisture 1.35%, volatile matter (V) 31.36%, ash (Ash) 20.79%, and water of crystallization 5.5%. Combustible and volatile element analysis includes: total carbon content 41.0%, hydrogen content 6.5%, oxygen content 27.5%, nitrogen content 3.22%, sulfur content 0.99%, with the balance being ash; wherein, the ash composition of the pulverized coal, by mass percentage, includes: SiO2 8.99%, CaO 44.1%, MgO 2.76%, Al2O3 7.9%, and TiO2 0.77%. The heat of decomposition of the lignite is 2834 KJ / kg.

[0151] B. Regarding the setting of raw materials and indicators, the feed material must meet the following requirements: ore batch weight is 33,000 kg (ore batch (kg) and furnace volume (m³)). 3 The ratio is 30.6 kg / m³. 3 The dry basis coke batch weight is 8100 kg / batch (including 600 kg / batch of dry basis small-particle coke); the dry basis coke load is 4.40; anthracite, bituminous coal, and lignite are blended according to the proportions selected in Table 1, and the ignition point, grindability index, and average combustion rate (dW / dt) of the mixed coal powder are as follows. mean Maximum combustion rate (dW / dt) mean See Table 2. For the mixed coal powder obtained by selecting the proportions of anthracite, bituminous coal and lignite, under the condition of maintaining the original batch weight of coke, the hourly injection rate determined according to formula (1) is shown in Table 2.

[0152] Table 2. Hourly Coal Injection Rate Determined by Changes in Mixed Pulverized Coal Composition in Examples 1-5

[0153]

[0154] C. Smelting is carried out under the following conditions: hot blast pressure (P), pressure difference (P) 压差 ), hot air temperature (T) 风 ), Furnace air volume (V) 风 ), oxygen enrichment in the blower (V) 氧 (The oxygen enrichment input value is used to meet the actual theoretical combustion temperature setpoint), pulverized coal injection ratio (M 煤 The injection rate and actual material speed control are shown in Table 3; the set theoretical combustion temperature (T) L 2250~2450℃; the composition and heat balance control of the furnace hearth gas are shown in Tables 3 and 4;

[0155] In step C, both the theoretical material rate and the actual material rate meet the defined requirements;

[0156] The set suitable theoretical combustion temperature (T) L The suitable theoretical combustion temperature (i.e., the baseline theoretical combustion temperature value before the change of the pulverized coal structure) is 2345℃.

[0157] In Table 3, (T) LC The value is the theoretical combustion temperature calculated according to the traditional calculation model (reference [1]). Special note: (T) LC The calculated value of T differs significantly from the theoretical combustion temperature constructed in this invention. The calculation model constructed in this invention reflects the influence of hydrogen content and decomposition heat on the theoretical combustion temperature of mixed pulverized coal as the proportion of lignite increases. The operation of this invention is used to measure T... L The value provides a stable equilibrium;

[0158] Table 3 Smelting parameters for Examples 1-5

[0159]

[0160] Table 4 Smelting parameters for Examples 1-5 Table 2

[0161]

[0162] In this embodiment, the hourly oxygen input in 1-5 satisfies the equilibrium theoretical combustion temperature (T). L (Value requirement, continue)

[0163] D. The following controls are implemented during the smelting process: 0.65% powder for sintered ore and 0.69% powder for pelletized ore; Slag control includes: magnesium oxide (w(MgO)), titanium oxide (w(TiO2)), aluminum oxide (w(Al2O3)), magnesium-aluminum ratio (w(MgO) / w(Al2O3)), and slag basicity (w(CaO) / w(SiO2)) (see Table 4); Smelting parameter control includes: furnace top temperature (T... 顶 ), wind temperature (T) 风 ), oxygen enrichment rate Air permeability index (permeability index), theoretical combustion temperature (T) L See Table 5; Gas flow parameter control: Furnace gas volume (V) BM ), Furnace gas development index (X) BM ), air permeability resistance coefficient (K) Z The control measures are shown in Table 5.

[0164] Table 5. Slag composition and smelting parameters for Examples 1-5

[0165]

[0166] E. After smelting, qualified low-silicon pig iron with the following indicators is obtained; and slag and iron are tapped in parallel tapping mode to obtain qualified low-silicon pig iron; the comprehensive grade of the furnace feed corresponding to Examples 1-5 is 53.69%; the implementation effect of each blended coal ratio is shown in Table 4, which are as follows: after adding high-cost-performance lignite fuel resources, the blast furnace utilization coefficient is 3.70~3.82t / (m³). 3.d), the injection ratio is 126.93~140.57kg / tFe; based on the different ratios (Table 1) of high-performance lignite fuel resources, the cost of pulverized coal fuel is reduced by RMB 4.32 / ton to RMB 21.80 / ton;

[0167] Table 6. Changes in smelting indicators and fuel costs in Examples 1-5

[0168]

[0169] F. Verify the blast furnace smelting fuel cost and utilization coefficient as follows: After adding high-performance lignite fuel resources, if the fuel cost continues to decrease and the blast furnace utilization coefficient is not lower than the range mentioned above, continue smelting.

[0170] Examples 6-10

[0171] Examples 6-10 are all at 1080m 3 The conventional ore smelting carried out in a blast furnace specifically includes the following steps:

[0172] A. Prepare materials as follows:

[0173] The ore mass percentages are as follows:

[0174] 72% of high-alkalinity common sinter.

[0175] Acidic oxidizing high-silica pellets 25%

[0176] 3% natural low-silica common lump ore

[0177] The sum of the above four types of minerals is 100%;

[0178] The coke is conventional high-ash coke, including small-particle coke;

[0179] The blast furnace tuyeres are injected with mixed pulverized coal, which is obtained by mixing anthracite, bituminous coal and lignite in the proportions shown in Table 7.

[0180] Table 7. Mixing ratio of pulverized coal in Examples 6-10, %

[0181] Item Anthracite Bituminous coal Lignite Reference 100 0 0 Example 6 80 20 0 Example 7 70 20 10 Example 8 60 20 20 Example 9 60 10 30 Example 10 60 5 35

[0182] in:

[0183] The chemical composition of the high-alkalinity ordinary sintered ore, by mass percentage, includes: TFe 52.60%, FeO 8.87%, SiO2 5.83%, CaO 11.118%, MgO 2.75%, TiO2 0.37%, V2O5 0.065%, S 0.022%, Al2O3 2.37%, MnO 0.204%. The ISO drum index is 79.11%, and the average particle size is 25.6 mm.

[0184] The chemical composition of the acidic oxidizing high-silica pellets, by mass percentage, includes: TFe 58.33%, FeO 1.01%, SiO2 7.95%, CaO 0.63%, MgO 2.41%, TiO2 0.75%, V2O5 0.033%, S 0.008%, Al2O3 2.26%, and MnO 0.23%; the particle size of the acidic oxidizing low-titanium pellets is 6mm to 16mm, and the compressive strength is 2344N / pellet.

[0185] The chemical composition of the natural low-silicon common lump ore, by mass percentage, includes: TFe 65.34%, SiO2 2.99%, CaO 0.035%, MgO 0.015%, S 0.012%, Al2O3 1.07%, MnO 0.19%, TiO2 0.011%, V2O5 0.028%; the particle size of the natural low-silicon common lump ore is 35mm, and the powder content in the furnace is 1.10%.

[0186] The chemical composition of the coke, by mass percentage, includes: moisture 2.8%, C 84.1%, Ash 13.22%, S 0.55%; M40 88.7%, M10 5.13%; CRI 26.7%, CSR 63.9%; wherein, the ash composition of the coke, by mass percentage, includes: SiO2 53.9%, CaO 2.87%, MgO 0.28%, Al2O3 25.5%;

[0187] The injected pulverized coal is prepared from anthracite, bituminous coal, and lignite with different carbon and hydrogen contents according to the proportions in Table 7. The chemical composition of the anthracite, by mass percentage, includes: moisture 1.1%, volatile matter 8.76%, ash 10.51%, and water of crystallization 0.93%. Combustible and volatile element analysis includes: a total carbon content of 78.7%, hydrogen content of 2.53%, oxygen content of 4.77%, nitrogen content of 2.93%, and sulfur content of 0.56%. The ash composition of the pulverized coal, by mass percentage, includes: SiO2 47.7%, CaO 5.75%, MgO 2.23%, Al2O3 24.9%, and TiO2 1.59%. The calorific value of the anthracite is 1100 KJ / kg.

[0188] The chemical composition of the bituminous coal, by mass percentage, includes: moisture 1.0%, volatile matter 13.0%, ash 10.49%, and water of crystallization 1.01%. Combustible and volatile element analysis includes: a total carbon content of 74.5%, hydrogen content of 4.71%, oxygen content of 5.71%, nitrogen content of 3.92%, sulfur content of 0.67%, with the balance being ash; wherein, the ash composition of the pulverized coal, by mass percentage, includes: SiO2 47.7%, CaO 5.35%, MgO 2.25%, Al2O3 23.9%, and TiO2 1.67%. The calorific value of the bituminous coal is 2054 KJ / kg.

[0189] The chemical composition of the lignite, by mass percentage, includes: moisture 1.2%, volatile matter (V) 33.47%, ash (Ash) 20.83%, and water of crystallization 5.8%. Combustible and volatile element analysis includes: total carbon content 38.7%, hydrogen content 6.7%, oxygen content 28.7%, nitrogen content 4.22%, sulfur content 0.85%, with the balance being ash; wherein, the ash composition of the pulverized coal, by mass percentage, includes: SiO2 9.23%, CaO 40.71%, MgO 2.35%, Al2O3 7.11%, and TiO2 0.81%. The calorific value of the lignite is 2966 KJ / kg.

[0190] B. Regarding the setting of raw materials and indicators, the feed material must meet the following requirements: ore batch weight is 36,000 kg (ore batch (kg) and furnace volume (m³)). 3 The ratio is 33.3 kg / m³. 3 The dry basis coke batch is 8500 kg / batch (including 600 kg / batch of dry basis small-particle coke); the dry basis coke load is 4.57; the ignition point, grindability index, and average combustion rate (dW / dt) of the mixed coal powder of anthracite, bituminous coal, and lignite according to the proportions selected in Table 1 are as follows. mean Maximum combustion rate (dW / dt) mean Table 8 shows the hourly injection rate determined by formula (1) for the mixed coal powder obtained by selecting the proportions of anthracite, bituminous coal and lignite, while maintaining the original batch weight of coke.

[0191] Table 8. Hourly Coal Injection Rate Determined by Changes in Mixed Pulverized Coal Composition in Examples 6-10

[0192]

[0193] C. Smelting is carried out under the following conditions: hot blast pressure (P), pressure difference (P) 压差 ), hot air temperature (T) 风 ), Furnace air volume (V) 风 ), oxygen enrichment in the blower (V) 氧(Input value for oxygen enrichment to meet the theoretical combustion temperature setpoint), pulverized coal injection ratio (M) 煤 The injection rate and actual material speed control are shown in Table 9. The set theoretical combustion temperature (T) L 2250~2450℃; the composition and heat balance control of the furnace hearth gas are shown in Tables 9 and 10;

[0194] In step C, both the theoretical material rate and the actual material rate meet the defined requirements;

[0195] The theoretical combustion temperature (T) set in Examples 6-10 of this embodiment is... L (The theoretical combustion temperature, i.e., the baseline theoretical combustion temperature value before the change of the pulverized coal structure, is 2300℃;)

[0196] In Table 9, (T) LC The value is the theoretical combustion temperature calculated according to the traditional calculation model (reference [1]). Special note: (T) LC The calculated value of T differs significantly from the theoretical combustion temperature constructed in this invention. The calculation model constructed in this invention reflects the influence of hydrogen content and decomposition heat on the theoretical combustion temperature of mixed pulverized coal as the proportion of lignite increases. The operation of this invention is used to measure T... L The value provides a stable equilibrium;

[0197] Table 9 Smelting parameters for Examples 6-10

[0198]

[0199] Table 10 Smelting parameters for Examples 6-10

[0200]

[0201] In this embodiment, the hourly oxygen input in 6-10 satisfies the equilibrium theoretical combustion temperature (T). L According to the required value, continue smelting;

[0202] D. The following controls are implemented during the smelting process: 0.75% powder for sintered ore and 0.77% powder for pelletized ore; Slag control includes: magnesium oxide (w(MgO)), titanium oxide (w(TiO2)), aluminum oxide (w(Al2O3)), magnesium-aluminum ratio (w(MgO) / w(Al2O3)), and slag basicity (w(CaO) / w(SiO2)) (see Table 11); Smelting parameter control includes: furnace top temperature (T... 顶 ), wind temperature (T) 风 ), oxygen enrichment rate Air permeability index (permeability index), theoretical combustion temperature (T) L See Table 11; Gas flow parameter control: Furnace gas volume (V) BM ), Furnace gas development index (X) BM), air permeability resistance coefficient (K) Z The control measures are shown in Table 11.

[0203] Table 11 Slag composition and smelting parameters of Examples 6-10

[0204]

[0205] E. After smelting, the following low-silicon qualified pig iron indicators are obtained; and slag and iron are tapped in parallel tapping mode to obtain low-silicon qualified pig iron; the corresponding comprehensive grade of the furnace feed is 54.41%; the implementation effect of each blended coal ratio is shown in Table 12; namely: after adding high-cost-performance lignite fuel resources, the blast furnace utilization coefficient increases to 3.61~3.76t / (m³). 3 .d), the injection ratio is 135.78~146.81kg / tFe; based on different ratios (Table 7), the cost of injection fuel is reduced by RMB 4.67 / ton to RMB 23.66 / ton after using high-performance lignite fuel resources;

[0206] Table 12 Changes in Smelting Indicators and Fuel Costs in Examples 6-10

[0207]

[0208] F. Verify the blast furnace smelting fuel cost and utilization coefficient as follows: After adding high-performance lignite fuel resources, if the fuel cost continues to decrease and the blast furnace utilization coefficient is not lower than the range mentioned above, continue smelting.

[0209] Examples 11-15

[0210] Examples 11-15 are all at 2500m 3 The conventional ore smelting carried out in a blast furnace specifically includes the following steps:

[0211] A. Prepare materials as follows:

[0212] The ore mass percentages are as follows:

[0213] 72% of high-alkalinity common sinter.

[0214] Acidic oxidizing high-silica pellets 23%

[0215] 5% natural low-silica common lump ore

[0216] The sum of the above four types of minerals is 100%;

[0217] The coke is conventional high-ash coke, including small-particle coke;

[0218] The blast furnace tuyeres are injected with mixed pulverized coal, which is obtained by mixing anthracite, bituminous coal and lignite in the proportions shown in Table 13.

[0219] Table 13. Mixing ratio of pulverized coal in Examples 11-15, %

[0220] Item Anthracite Bituminous coal Lignite Reference 100 0 0 Example 11 80 20 0 Example 12 70 20 10 Example 13 60 20 20 Example 14 60 10 30 Example 15 60 5 35

[0221] in:

[0222] The chemical composition of the high-alkalinity ordinary sintered ore, by mass percentage, includes: TFe 54.86%, FeO 8.22%, SiO2 5.11%, CaO 12.009%, MgO 2.85%, TiO2 0.17%, V2O5 0.033%, S 0.016%, Al2O3 2.09%, MnO 0.209%. The ISO drum index is 81.23%, and the average particle size is 28.6 mm.

[0223] The chemical composition of the acidic oxidizing high-silica pellets, by mass percentage, includes: TFe 60.13%, FeO 1.21%, SiO2 7.15%, CaO 0.66%, MgO 2.11%, TiO2 0.79%, V2O5 0.022%, S 0.000%, Al2O3 2.09%, and MnO 0.22%; the particle size of the acidic oxidizing low-titanium pellets is 6mm to 16mm, and the compressive strength is 2377N / pellet.

[0224] The chemical composition of the natural low-silicon common lump ore, by mass percentage, includes: TFe 65.34%, SiO2 2.99%, CaO 0.035%, MgO 0.015%, S 0.012%, Al2O3 1.07%, MnO 0.19%, TiO2 0.011%, V2O5 0.028%; the particle size of the natural low-silicon common lump ore is 35mm, and the powder content in the furnace is 1.10%.

[0225] The chemical composition of the coke, by mass percentage, includes: moisture 2.8%, C 86.1%, Ash 13.02%, S 0.55%; M40 88.9%, M10 4.77%; CRI 25.0%, CSR 66.9%; wherein, the ash composition of the coke, by mass percentage, includes: SiO2 55.9%, CaO 2.99%, MgO 0.22%, Al2O3 24.8%;

[0226] The injected pulverized coal is prepared from anthracite, bituminous coal, and lignite with different carbon and hydrogen contents according to the proportions in Table 13. The chemical composition of the anthracite, by mass percentage, includes: moisture 0.8%, volatile matter 8.78%, ash 10.31%, and water of crystallization 0.91%. Combustible and volatile element analysis includes: a total carbon content of 79.2%, hydrogen content of 2.55%, oxygen content of 4.66%, nitrogen content of 2.73%, and sulfur content of 0.55%. The ash composition of the pulverized coal, by mass percentage, includes: SiO2 47.7%, CaO 5.75%, MgO 2.23%, Al2O3 24.9%, and TiO2 1.59%. The heat of decomposition of the anthracite is 1111 KJ / kg.

[0227] The chemical composition of the bituminous coal, by mass percentage, includes: moisture 1.0%, volatile matter 13.04%, ash 9.71%, and water of crystallization 1.05%. Combustible and volatile element analysis includes: a total carbon content of 75.2%, hydrogen content of 4.71%, oxygen content of 5.91%, nitrogen content of 3.77%, sulfur content of 0.66%, with the balance being ash; wherein, the ash composition of the pulverized coal, by mass percentage, includes: SiO2 48.1%, CaO 5.76%, MgO 2.19%, Al2O3 24.2%, and TiO2 1.60%. The calorific value of the bituminous coal is 2071 KJ / kg.

[0228] The chemical composition of the lignite, by mass percentage, includes: moisture 1.1%, volatile matter (V) 32.51%, ash (Ash) 20.49%, and water of crystallization 6.6%. Combustible and volatile element analysis includes: total carbon content 39.3%, hydrogen content 6.77%, oxygen content 28.4%, nitrogen content 4.33%, sulfur content 0.71%, with the balance being ash; wherein, the ash composition of the pulverized coal, by mass percentage, includes: SiO2 8.73%, CaO 41.97%, MgO 2.24%, Al2O3 7.01%, and TiO2 0.87%. The heat of decomposition of the lignite is 2951 KJ / kg.

[0229] B. Regarding the setting of raw materials and indicators, the feed material must meet the following requirements: ore batch weight is 60,000 kg (ore batch (kg) and furnace volume (m³)). 3 The ratio is 24.0 kg / m³. 3 The dry basis coke batch is 1330 kg / batch (including 1000 kg / batch of dry basis small-particle coke); the dry basis coke load is 4.88; the ignition point, grindability index, and average combustion rate (dW / dt) of the mixed coal powder of anthracite, bituminous coal, and lignite according to the proportions selected in Table 1 are as follows. mean Maximum combustion rate (dW / dt) meanTable 14; For the mixed coal powder obtained by selecting the proportions of anthracite, bituminous coal and lignite, under the condition of maintaining the original batch weight of coke, the hourly injection rate determined according to the formula (1) is shown in Table 14.

[0230] Table 14 Hourly Pulverized Coal Injection Rate Determined by Changes in Mixed Pulverized Coal Composition in Examples 11-15

[0231]

[0232] C. Smelting is carried out under the following conditions: hot blast pressure (P), pressure difference (P) 压差 ), hot air temperature (T) 风 ), Furnace air volume (V) 风 ), oxygen enrichment in the blower (V) 氧 (Input value for oxygen enrichment to meet the theoretical combustion temperature setpoint), pulverized coal injection ratio (M) 煤 The injection rate and actual material speed control are shown in Table 15; the set theoretical combustion temperature (T) L 2250~2450℃; the composition and heat balance control of the furnace hearth gas are shown in Tables 15~16;

[0233] In step C, both the theoretical material rate and the actual material rate meet the defined requirements;

[0234] The suitable theoretical combustion temperature (T) set in Examples 11-15 of this embodiment is L The suitable theoretical combustion temperature (i.e., the baseline theoretical combustion temperature value before the change of the pulverized coal structure) is 2215℃.

[0235] In Table 15, (T) LC The value is the theoretical combustion temperature calculated based on the traditional calculation model (reference [1]); Special note: (T) LC The calculated value of T differs significantly from the theoretical combustion temperature constructed in this invention. The calculation model constructed in this invention reflects the influence of hydrogen content and decomposition heat on the theoretical combustion temperature of mixed pulverized coal as the proportion of lignite increases. The operation of this invention is used to measure T... L The value provides a stable equilibrium;

[0236] Table 15 Smelting parameters for Examples 11-15

[0237]

[0238] Table 16 Smelting parameters for Examples 11-15

[0239]

[0240] In this example, the hourly oxygen input satisfies the equilibrium theoretical combustion temperature (T). L According to the required value, continue smelting;

[0241] D. The following controls are implemented during the smelting process: The powder content of sintered ore fed into the furnace is controlled at 0.67%, and the powder content of pelletized ore fed into the furnace is controlled at 0.70%; the following controls are implemented in the slag: magnesium oxide (w(MgO)), titanium oxide (w(TiO2)), aluminum oxide (w(Al2O3)), magnesium-aluminum ratio in the slag (w(MgO) / w(Al2O3)), and slag basicity (w(CaO) / w(SiO2)) are shown in Table 4; smelting parameters are controlled: furnace top temperature (T... 顶 ), wind temperature (T) 风 ), oxygen enrichment rate Air permeability index (permeability index), theoretical combustion temperature (T) L See Table 17; Gas flow parameter control: Furnace gas volume (V) BM ), Furnace gas development index (X) BM ), air permeability resistance coefficient (K) Z The controls are shown in Table 17;

[0242] Table 17 Slag composition and smelting parameters of Examples 11-15

[0243]

[0244] E. After smelting, the following low-silicon qualified pig iron is obtained; and the slag and iron are tapped in a parallel tapping mode to obtain low-silicon qualified pig iron. In this example, it is 2500m. 3 The blast furnace was used for ordinary ore smelting, with a corresponding comprehensive feed grade of 56.64%. The effects of different blending ratios are shown in Table 18. Specifically, after incorporating high-performance lignite fuel, the blast furnace utilization coefficient increased to 3.61–3.76 t / (m³). 3 .d), the injection ratio is 135.78~146.81kg / tFe; based on different ratios (Table 13), the cost of injection fuel is reduced by RMB 7.99 / ton to RMB 31.64 / ton after using high-performance lignite fuel resources;

[0245] Table 18 Changes in Smelting Indicators and Fuel Costs in Examples 11-15

[0246]

[0247] F. Verify the blast furnace smelting fuel cost and utilization coefficient as follows: After adding high-performance lignite fuel resources, if the fuel cost continues to decrease and the blast furnace utilization coefficient is not lower than the range mentioned above, continue smelting.

[0248] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

[0249] References:

[0250] [1] Zhou Chuandian. Blast Furnace Ironmaking Process Production Technology Manual [M]. Beijing: Metallurgical Industry Press, 2008.

[0251] [2] Xiang Zhongyong, Wang Xiaoliu, et al., Blast Furnace Design - Theory and Practice of Blast Furnace Process Design [M]. Beijing: Metallurgical Industry Press, 2012.

Claims

1. A method for enhancing blast furnace smelting by increasing combustion temperature based on equilibrium theory, characterized in that, Includes the following steps: A. Prepare materials as follows: The ore mass percentages are as follows: High-basicity sinter 60-75%, Acidic oxidizing vanadium-titanium pellets 0-35%, Acidic, oxidizing, high-silica common pellets, 0-25%, Natural low-silicon common lump ore 0-5%, The sum of the above four types of minerals is 100%; The coke is high-ash coke and small-particle coke; The pulverized coal mixture for injection is obtained by mixing anthracite, bituminous coal, and lignite with different carbon and hydrogen contents in any proportion; B. The raw materials and specifications are set, with a volume of 1080m³. 3 ~2500m 3 The blast furnace is configured as follows: Ore weight: 20-35 kg / m 3 ; Dry basis coke batch weight: 7500~14000kg / batch, including dry basis small particle coke batch weight: 500~1000kg / batch; Dry basis coke load: 4.20~5.00; Pulverized coal injection rate at the tuyere: 19.0~60.0t / h; Theoretical combustion temperature: (2250~2450℃)±5℃; For a mixed coal powder obtained by any proportion of anthracite, bituminous coal and lignite, under the condition of maintaining the dry basis coke batch weight, the hourly injection rate of the mixed coal powder after the change of the coal powder mixing ratio is determined according to the carbon and hydrogen content in the selected mixed coal powder, and the ignition point, grindability index, average combustion rate and maximum combustion rate of the mixed coal powder are verified. C. Smelting shall be carried out under the following conditions: hot blast pressure: 0.30~0.45MPa, pressure difference: 0.5 times hot blast pressure ±0.005MPa, hot blast temperature: 1180~1250℃, furnace air volume: 3000~6500m³ 3 / min, oxygen enrichment in the blower: 9000~30000m³ 3 / h, pulverized coal injection ratio: 110~180kg / t iron, injection rate: 21.0~35.0%; material rate: 7.5~10.5 batches; furnace hearth gas composition control: CO: 35~45%, H2: 3.0~10.0%, N2: 50%~60%; During the smelting process, the theoretical material rate and the actual material rate are verified. During the smelting process, the maximum blast temperature is fixed, and the actual theoretical combustion temperature is calculated. This actual theoretical combustion temperature remains balanced and stable within a certain range, and the balanced and stable actual theoretical combustion temperature is used as the basis for adjusting the injection of mixed pulverized coal and the oxygen enrichment. D. The following controls shall be implemented during the smelting process: The content of sintered ore and pellet powder fed into the furnace is <1.0%; The slag contains: magnesium oxide 7.5%–11.0%, titanium oxide 3.0%–17.0%, aluminum oxide 10.5%–13.5%, magnesium-aluminum ratio 0.70–0.98, and slag basicity 1.05–1.

25. The furnace top temperature is 100–260℃, the hot air temperature is 1180–1250℃, the oxygen enrichment rate is 3.5–7.0%, and the air permeability index is 15000–30000 m³. 3 / min.MPa, furnace gas volume 4000~8000m³ 3 / min, furnace gas development index 79.0~83.0m / min, permeability resistance coefficient 3.5~8.0; E. Low-silicon qualified pig iron with the following indicators is obtained after smelting; For 1080m 3 The blast furnace has an overall ore grade of 53.5%–54.5% and a blast furnace utilization coefficient of 3.65–3.85 t / m³. 3 .d, injection ratio 120-150 kg / t iron; For 2500m 3 The blast furnace has an overall ore grade of 55.8%–56.8% and a blast furnace utilization coefficient of 2.75–3.10 t / m³. 3 .d, injection ratio 150-180 kg / t iron; F. Verify the blast furnace smelting fuel cost and utilization coefficient as follows: If the fuel cost continues to decrease and the blast furnace utilization coefficient is not lower than the range in step E, then continue smelting.

2. The method for enhancing blast furnace smelting based on equilibrium theory combustion temperature according to claim 1, characterized in that: The chemical composition (mass percentage) of each raw material is as follows: The chemical composition (mass percentage) of the high-basicity sinter is as follows: TFe: 52.0–54.0%, FeO: 8.00–9.00%, SiO2: 5.0–6.5%, CaO: 12.0–13.5%, MgO: 2.60–3.00%, TiO2: 0.15–1.50%, V2O5: 0.100–0.170%, S: 0.035–0.065%, Al2O3: 2.00–2.30%, MnO: 0.10–0.30%, with the balance being unavoidable impurities; the high-basicity sinter drum index is 78.0%–80.0%, and the average particle size is 20–50 mm. The chemical composition (by mass percentage) of the acidic oxidized vanadium-titanium pellets is as follows: TFe: 53.5–58.0%, FeO: 1.30–2.50%, SiO2: 4.50–5.50%, CaO: 0.50–1.50%, MgO: 2.35–2.75%, TiO2: 6.0–11.0%, V2O5: 0.50–0.95%, S: 0.008–0.015%, Al2O3: 2.50–3.00%, MnO: 0.23–0.30%, with the balance being unavoidable impurities. The particle size of acidic oxidizing vanadium-titanium pellets is 6mm to 16mm, and the compressive strength is >2200N / pellet. The chemical composition (mass percentage) of the acidic oxidizing high-silica ordinary pellets is as follows: TFe: 58.0–59.5%, FeO: 1.10–1.50%, SiO2: 6.50–7.00%, CaO: 0.50–1.50%, MgO: 2.00–2.50%, TiO2: 0.59–1.50%, V2O5: 0.50–0.95%, S: 0.01–0.025%, Al2O3: 2.50–3.00%, MnO: 0.20–0.30%, with the balance being unavoidable impurities; the particle size of the acidic oxidizing high-silica ordinary pellets is 6 mm–16 mm, and the compressive strength is >2200 N / particle; The chemical composition (mass percentage) of the natural low-silicon common lump ore is as follows: TFe: 64.0–66.0%, SiO2: 2.5–4.0%, CaO: 0.025–0.055%, MgO: 0.005–0.025%, S: 0.010–0.020%, Al2O3: 1.00–1.10%, MnO: 0.15–0.25%, TiO2: 0.005–0.015%, V2O5: 0.025–0.035%, with the balance being unavoidable impurities; the particle size of the natural low-silicon common lump ore is 25 mm–45 mm, and the powder content in the furnace is <1.50%; The chemical composition of the coke, by mass percentage, is as follows: Moisture: 0.8–4.2%, C: 83.0–86.0%, Ash: 12.5–13.8%, S: 0.50–0.65%, with the balance being unavoidable impurities; M40: 85.0–89.0%, M10: 4.10–5.10%; CRI: 22.0–26.0%, CSR: 63.0–68.0%. The mass percentage composition of coke ash is as follows: SiO2: 53.0-54.0%, CaO: 2.0-2.5%, MgO: 0.10-0.30%, Al2O3: 23.0-25.0%, with the balance being unavoidable impurities; The injected pulverized coal mixture is obtained by mixing anthracite, bituminous coal, and lignite in any proportion with different carbon and hydrogen contents, wherein: The anthracite's chemical composition by mass percentage is as follows: moisture: 0.5–1.5%, volatile matter (V): 7.0–9.0%, ash (Ash): 9.5–12.0%, water of crystallization: 0.8–1.2%; combustible and volatile elements include: total carbon content 78.0–80.0%, hydrogen content 2.0–3.0%, oxygen content 3.5%–5.5%, nitrogen content 1.0%–3.0%, sulfur content 0.55–0.70%, with the balance being ash; wherein, the ash composition of the pulverized coal by mass percentage is as follows: SiO2: 47.0–48.0%, CaO: 5.0–5.5%, MgO: 2.0–2.5%, Al2O3: 23.0–25.0%, TiO2: 1.5–1.7%, with the balance being unavoidable impurities; the anthracite's heat of decomposition is 1050–1100 KJ / kg; The chemical composition of the bituminous coal, by mass percentage, is as follows: moisture: 0.5–1.5%, volatile matter (V): 13.0–15.0%, ash (Ash): 10.0–13.0%, water of crystallization: 1.0–2.0%; combustible and volatile elements include: total carbon content 74.0–76.0%, hydrogen content 4.0–6.0%, oxygen content 4.5%–6.5%, nitrogen content 2.0%–4.0%, sulfur content 0.55–0.70%, with the balance being ash; wherein, the ash composition of the pulverized coal, by mass percentage, includes: SiO2: 47.0–48.0%, CaO: 5.0–5.5%, MgO: 2.0–2.5%, Al2O3: 23.0–25.0%, TiO2: 1.5–1.7%, with the balance being unavoidable impurities; the calorific value of the bituminous coal is 1900–2100 KJ / kg; The lignite's chemical composition by mass percentage includes: moisture: 0.5–1.5%, volatile matter (V): 30.0–40.0%, ash (Ash): 20.0–30.0%, and water of crystallization: 3.0–10.0%; combustible and volatile elements include: total carbon content 40.0–50.0%, hydrogen content 6.0–8.0%, oxygen content 25.0%–35.0%, nitrogen content 2.0%–4.0%, sulfur content 0.80–1.20%, with the balance being ash; wherein, the ash composition of the pulverized coal by mass percentage includes: SiO2: 8.0–10.0%, CaO: 40.0–45.0%, MgO: 2.0–3.5%, Al2O3: 7.0–8.5%, TiO2: 0.5–1.0%, with the balance being unavoidable impurities; the lignite's calorific value is 2750–2950 KJ / kg.

3. The blast furnace smelting method based on theoretical combustion temperature equilibrium calculation according to claim 1, characterized in that: In step B, the hourly injection rate (M) of the mixed pulverized coal after the change in the pulverized coal mixing ratio is... h The formula for determining this is: Where: M h The hourly pulverized coal injection rate after changes in the pulverized coal mixing ratio, unit: kg·h -1 M j The hourly base pulverized coal injection rate before changes in the pulverized coal mixing ratio, unit: kg·h -1 ;w(C) j The carbon content of the pulverized coal before the change in the pulverized coal mixing ratio is expressed in % (w(H)). j The hydrogen content of the pulverized coal before the change in the pulverized coal mixing ratio is expressed in % (w(C)). h The carbon content of pulverized coal after changes in the pulverized coal mixing ratio is expressed in %; w(H) h The hydrogen content of pulverized coal after changes in the pulverized coal mixing ratio is expressed in %; The ignition point, grindability index, average combustion rate, and maximum combustion rate of the mixed pulverized coal are verified as follows: the mixed pulverized coal must have an ignition point >280℃, a grindability index of 55%–65%, and an average combustion rate (dW / dt). mean 4.0~6.0%·min -1 Maximum combustion rate (dW / dt) mean 6.0~8.5%·min -1 If the verification is successful, smelting can continue.

4. The blast furnace smelting method based on theoretical combustion temperature balance calculation according to claim 1, characterized in that: In step C, the theoretical material rate and the actual material rate are verified as follows: if |theoretical material rate - actual material rate| < 0.5 batches / hour, or the absolute value of the difference between the theoretical material rate and the actual material rate for two consecutive hours is < 1 batch / hour, the verification is passed and smelting continues. In step C, the air temperature is controlled to be the highest value that can be stably reached during the smelting process. The actual theoretical combustion temperature is calculated as follows: C1) Calculate the hearth gas volume, which is the sum of the volume of CO, H2, and N2 components in the hearth gas. The percentage of CO, H2, and N2 components in the blast furnace hearth gas is the ratio of the volume of each component to the total hearth gas volume. The H2 content in the hearth gas increases with the increase of hydrogen content in the mixed pulverized coal, which increases the hearth gas volume and decreases the actual theoretical combustion temperature. The volumetric composition of CO, H2, and N2 in the blast furnace hearth gas is calculated using the following formula: The volume of H2 in the blast furnace hearth gas is calculated using the following formula: In the formula: The volume of H2 in the hearth gas produced to produce 1 ton of iron, in cubic meters. 3 ·t -1 V B The amount of air required to produce 1 ton of iron, in meters. 3 ·t -1 ; The increase in oxygen content in the air volume consumed to produce 1 ton of iron, in m³. 3 ·t -1 ; M h The ratio of pulverized coal to pulverized coal is given in kg·t. -1 ; Φ m Combustion rate of mixed pulverized coal, unit: %; b s The amount of air transported for conveying the mixed pulverized coal, in cubic meters (m³). 3 ·kg -1 ; The relative humidity of the air in the blower, in %; Hydrogen content of mixed pulverized coal, unit: %; The physical moisture content of the mixed pulverized coal is expressed in %; where: The calculation formula is as follows: In the formula: The oxygen content in the blower air, in %; The relative humidity of the atmosphere in the blower, in %; V B The amount of air required to produce 1 ton of iron, in meters. 3 ·t -1 ; Oxygen content in the blower The calculation formula is as follows: In the formula: The relative humidity of the air in the blower, in %; Oxygen enrichment rate of the blower, unit: %; Blower oxygen enrichment rate The calculation formula is as follows: In the formula: The hourly oxygen enrichment in the blower air, unit: m³ 3 ·h -1 V f The actual blast volume injected into the blast furnace, in m³. 3 ·min -1 ; The formula for calculating the volume of N2 in the blast furnace hearth gas is as follows: In the formula: The volume of N2 in the hearth gas produced to produce 1 ton of iron, in cubic meters. 3 ·t -1 V B The amount of air required to produce 1 ton of iron, in meters. 3 ·t -1 ; The increase in oxygen content in the air volume consumed to produce 1 ton of iron, in m³. 3 ·t -1 M h The ratio of pulverized coal to pulverized coal is given in kg·t. -1 b s The amount of air transported for conveying the mixed pulverized coal, in cubic meters (m³). 3 ·kg -1 ; The relative humidity of the air in the blower, in %; Oxygen enrichment rate of the blower, unit: %; Nitrogen content in oxygen-enriched blower air, unit: %; Nitrogen content in mixed pulverized coal, unit: %; Φ MC Combustion rate of mixed pulverized coal before the tuyeres, unit: %; The formula for calculating the volume of CO in the blast furnace hearth gas is as follows: In CO =(K J ×C J ×φ JC / 10000+M h ×C M ×φ MC / 10000) / 12×22.4 (6) In the formula: V CO The volume of CO in the hearth gas produced to produce 1 ton of iron, in cubic meters. 3 ·t -1 ;K J The amount of dry coke consumed to produce 1 ton of iron, in kg·t -1 C J Carbon content in dry coke, unit: %; Φ JC Coke combustion rate before the tuyeres; unit: %; M h The ratio of pulverized coal to pulverized coal is given in kg·t. -1 C M Carbon content in mixed pulverized coal, unit: %; Φ MC Combustion rate of mixed pulverized coal before the tuyeres, in %; During the smelting process, the actual theoretical combustion temperature is calculated to remain balanced and stable within a certain range. The balanced and stable actual theoretical combustion temperature is used as the basis for adjusting the injection of mixed coal powder and the oxygen enrichment. The hourly injection rate of mixed coal powder is calculated according to formula (1). The oxygen enrichment is directly input as the hourly oxygen enrichment flow rate until the calculated actual theoretical combustion temperature meets the set theoretical combustion temperature (2250~2450℃) ±5℃. C2), the actual theoretical combustion temperature is calculated as follows: The control process for the theoretical combustion temperature is as follows: basic data → establishment of the theoretical combustion temperature calculation model → input of mixed pulverized coal ratio → input of hourly injection rate of mixed pulverized coal calculated by equation (1) → input of arbitrary hourly oxygen enrichment → composition of furnace gas → thermal balance of tuyeres area → theoretical combustion temperature → theoretical analysis; where: The basic data includes: raw material composition, grindability and combustibility of mixed coal powder, decomposition endothermic data, etc. The actual theoretical combustion temperature (T) L The calculation model for ) is as follows: In the formula: T L Q represents the theoretical combustion temperature during intensified smelting using pulverized coal injection, in °C. C The heat released when carbon burns to produce CO in front of the vent, measured in kJ·t. -1 Q RF The amount of hot air blown in and the physical heat it carries is measured in kJ·t. -1 Q HH The physical heat introduced by the carrier gas during the injection of mixed pulverized coal, in kJ·t. -1 Q R The sensible heat brought in by coke entering the combustion zone, unit: kJ·t -1 Q X1 The heat absorbed by the decomposition of moisture in the blower air is expressed in kJ·t. -1 Q X2 The decomposition endothermic reaction of mixed pulverized coal injected during the blast furnace for smelting 1 ton of iron is given in kJ·t. -1 V g The volume of hearth gas produced in the smelting of 1 ton of iron, in m³. 3 ·t -1 c p t To generate hearth gas at T L Specific heat capacity at temperature, unit: kJ·(m³) 3 ·℃) -1 ; in: In the formula: Q X1 The heat absorbed by the decomposition of moisture in the blower air is expressed in kJ·t. -1 V B The amount of air required to produce 1 ton of iron, in meters. 3 ·t -1 ; The increase in oxygen content in the air volume consumed to produce 1 ton of iron, in m³. 3 ·t -1 b s The amount of air transported for conveying the mixed pulverized coal, in cubic meters (m³). 3 ·kg -1 M h The ratio of pulverized coal to pulverized coal is given in kg·t. -1 ; The relative humidity of the air in the blower, in %; Q X2 =Q HM ×M h (9) In the formula: Q HM The heat of decomposition per unit mass of mixed pulverized coal, unit: kJ·kg -1 M h The ratio of mixed pulverized coal injection is expressed in kg·t. -1 ; In the formula: The volume of H2 in the hearth gas produced to produce 1 ton of iron, in cubic meters. 3 ·t -1 V CO The volume of CO in the hearth gas produced to produce 1 ton of iron, in cubic meters. 3 ·t -1 ; The volume of N2 in the hearth gas produced to produce 1 ton of iron, in cubic meters. 3 ·t -1 ; In formula (5), the remaining Q C Q RF Q HH Q R The parameter calculation formula is as follows: Q C =9797×(K J ×C J / 100×φ JC / 100+M h ×C M / 100×φ MC / 100) (11) In the formula: Q C K represents the heat released when carbon burns to produce CO in front of the vent. J The amount of dry coke consumed to produce 1 ton of iron, in kg·t -1 C J Carbon content in dry coke, unit: %; Φ JC M represents the coke combustion rate before the tuyeres. h The ratio of pulverized coal to pulverized coal is given in kg·t. -1 C M Carbon content in mixed pulverized coal, unit: %; Φ MC Combustion rate of mixed pulverized coal before the tuyeres, unit: %. In the formula: Q RF To blow in hot air and bring in physical heat, V B The amount of air required to produce 1 ton of iron, in meters. 3 ·t -1 ; The increase in oxygen content in the air volume consumed to produce 1 ton of iron, in m³. 3 ·t -1 ;T F The hot air temperature is in °C. Q HH =M h ×b s ×T M ×1.3084 (13) In the formula: Q HH The physical heat introduced by the carrier gas during the injection of mixed pulverized coal; T M Carrier gas temperature, unit: °C; b s The amount of air transported for conveying the mixed pulverized coal, in cubic meters (m³). 3 ·kg-1; M h The pulverized coal injection ratio is expressed as a percentage (%). Q R =2300×K J ×φ JC (14) In the formula: Q R This refers to the sensible heat brought in by the coke as it enters the combustion zone; K J The amount of dry coke consumed to produce 1 ton of iron, in kg·t -1 ;Φ JC The coke combustion rate in front of the tuyere, in %; Calculate the actual theoretical combustion temperature (T) L When, based on the obtained enthalpy value of the mixed gas in the furnace hearth The enthalpy of the mixed gas at different temperatures was calculated using conventional interpolation. Calculate the actual theoretical combustion temperature (T) L The formula for calculating the enthalpy of the mixed gas in the furnace hearth at the given value is as follows: In the formula: The actual theoretical combustion temperature (T) during the intensified smelting of mixed pulverized coal. L The enthalpy of the mixed gas under the given conditions, in kJ·(m³) 3 ·t) -1 Q C The heat released when carbon burns to produce CO in front of the vent, measured in kJ·t. -1 Q RF The amount of hot air blown in and the physical heat it carries is measured in kJ·t. -1 Q HH The physical heat introduced by the mixed pulverized coal carrier gas, unit: kJ·t -1 Q R The sensible heat brought in by coke entering the combustion zone, unit: kJ·t -1 Q X1 The heat absorbed by the decomposition of moisture in the blower air is expressed in kJ·t. -1 Q X2 The decomposition endothermic heat of the mixed pulverized coal injected into the blast furnace required to smelt 1 ton of iron, unit: kJ·t -1 V g The volume of hearth gas produced for smelting 1 ton of iron, in m³. 3 ·t -1 .

5. The blast furnace smelting method based on theoretical combustion temperature balance calculation according to claim 1, characterized in that: In step D, the calculation of the furnace gas volume, furnace gas development index, and permeability resistance coefficient is obtained through conventional calculation formulas, as follows: Furnace gas volume V BG The calculation formula is: In the formula: V F Actual air volume entering the furnace, unit: m³ 3 ·min -1 ; Oxygen enrichment, unit: m 3 ·h -1 W B Absolute humidity of the atmosphere during blower operation, unit: g·m -3 ;P C The injection rate of mixed pulverized coal is expressed in kg·h. -1 H represents the hydrogen content of pulverized coal, in %; The formula for calculating the air permeability resistance coefficient K is: In the formula: P B The absolute pressure of the blower is 10 kPa; P T The absolute pressure at the furnace top is 10 kPa; V BG This refers to the volume of gas in the furnace belly, in cubic meters. 3 ·t -1 ; Furnace gas development index x BG The calculation formula is: In the formula: d is the diameter of the furnace hearth, in meters; V BG This refers to the volume of gas in the furnace belly, in cubic meters. 3 ·t -1 .

6. The blast furnace smelting method based on theoretical combustion temperature balance calculation according to claim 1, characterized in that... In step F: When verifying the blast furnace utilization coefficient of blast furnaces with different volumes, if the verification conditions are not met, the reasons should be investigated and the parameters adjusted. When verifying fuel costs, if the verification conditions are not met, the reason is investigated; if fuel costs continue to decrease and the blast furnace utilization coefficient is not lower than the range of the aforementioned steps, smelting continues.

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