Vanadium titano-magnetite blast furnace smelting method with addition of lignite injection

Abstract

The present application relates to a kind of vanadium-titanium magnetite adding lignite injection blast furnace smelting method, belong to blast furnace smelting technical field.It includes the following steps: A, ore, coke is sent into blast furnace, while injecting mixed coal powder;B, the condition of raw fuel into furnace is defined;C, smelting;D, slag, iron is discharged.The present application is in the case where low-silicon high basicity vanadium-titanium sinter, low-silicon vanadium-titanium pellet or high-silicon acid oxide pellet and ash, sulfur content higher coke are used as raw material into furnace, with high hydrogen high volatile low ash low price lignite is mixed and injected, fully utilizes the abundant resource, low price lignite resource, solves the problems such as low utilization coefficient, low coal injection ratio, single source of coal powder injection, high fixed carbon content, strong dependence on anthracite or lean coal resources in the intensified smelting of vanadium-titanium magnetite, improves utilization coefficient, coal injection ratio, air temperature, improves desulfurization efficiency and smelting technical and economic index, reduces smelting cost and ton iron air consumption.

Description

Technical Field

[0001] This invention belongs to the field of resource utilization and blast furnace smelting technology, specifically relating to a blast furnace smelting method for vanadium-titanium magnetite with lignite injection. Background Technology

[0002] In the steel production process, pig iron smelting costs account for 70-75% of the total cost per ton of steel, and the cost of raw materials and fuels for pig iron accounts for more than 90% of the total cost. In recent years, under the dual pressures of reducing steel production capacity and saving energy and reducing emissions, the competitive pressure in the steel industry has been continuously escalating. Improving the utilization of blast furnace smelting resources, enhancing quality, increasing output, reducing consumption, and lowering pig iron smelting costs have become key to enhancing the core competitiveness of the steel industry. Due to the uneven distribution of iron ore and coking coal resources globally and domestically, and influenced by the high prices of imported ore and high-quality coking coal, as well as rising logistics and transportation costs, it is crucial to utilize local or neighboring iron ore and coking coal resources to the maximum extent possible. This can be achieved by developing new blast furnace pulverized coal resources, optimizing the pulverized coal injection structure, and achieving complementary advantages based on resource characteristics. Furthermore, it is essential to find new suitable blast furnace operation methods, such as blending vanadium-titanium magnetite with locally sourced, inexpensive, and cost-effective lignite for enhanced smelting, improving the blast furnace fuel structure, and reducing costs. Ultimately, this approach aims to optimize the pulverized coal injection structure under vanadium-titanium magnetite smelting conditions, thereby increasing output, improving pulverized coal combustion efficiency, increasing the pulverized coal injection ratio, increasing the relative replacement ratio of pulverized coal injection, reducing air consumption per ton of iron, increasing the blast furnace utilization coefficient, and lowering the cost of pig iron production. It is also key to enhancing the core competitiveness of steel enterprises and improving energy conservation and emission reduction indicators.

[0003] After overcoming the challenges of high-ratio magnetite sintering methods and blast furnace vanadium-titanium magnetite intensified smelting methods, and using low-grade vanadium-titanium magnetite concentrate sintering technology, a series of high-intensity smelting methods for medium-titanium slag were successively developed. The system has systematically developed low-silicon, high-alkalinity vanadium-titanium sinter and low-silicon, high-titanium pellets that can be sintered on a large scale using cost-effective low-silicon vanadium-titanium iron concentrate resources from the Panxi region of Yunnan Province or surrounding areas. These pellets are supplemented with a small amount of self-produced high-silicon acidic oxidizing pellets and coke with higher ash content, sulfur content and lower fixed carbon content from Yunnan Province as blast furnace raw materials for long-term, high-intensity, and stable smelting of qualified pig iron. In Yunnan Province, coking coal and anthracite and bituminous coal suitable for blast furnace injection are scarce. However, lignite reserves are abundant, and its chemical composition and quality are relatively good. Compared with other coal types, lignite has a high hydrogen content and combustible volatile matter content, while its ash content is low. In addition, the CaO / SiO2 value of the ash content is very high. Overall, Yunnan Province has good quality local lignite resources, large reserves, and convenient mining, making it suitable for blast furnace injection. In particular, its price is very low, only one-third to one-half the price of pulverized coal currently used in blast furnaces.

[0004] As mentioned earlier, the key technologies previously obtained have solved problems such as low strength of sintered ore from local and surrounding vanadium-titanium magnetite resources, easy brittleness and powdering upon entering the furnace, and breakage. They have also solved the problems of intensified smelting using local and surrounding coke with high ash and sulfur content, unstable moisture and low calorific value. Furthermore, they have solved the shortcomings of daily intensified smelting using local and surrounding coke resources, such as large slag volume, high fuel ratio, large iron loss, high pig iron w([Si]) value and difficulty in stabilizing slag basicity. These technologies enable blast furnaces to achieve long-term stable operation. Based on the large-scale use of cost-effective vanadium-titanium magnetite resources in Panzhihua, a blast furnace intensified smelting method using lignite injection has been developed. This has become one of the important ways to reduce the coke ratio, increase the pulverized coal injection ratio, improve the blast furnace utilization coefficient and enhance the competitiveness of ironmaking products in inland blast furnace smelting.

[0005] The advantages of lignite resources in Yunnan and surrounding areas are: abundant reserves, convenient mining, and low price. Compared with other coal types, it is superior in terms of chemical composition and quality. Lignite has high hydrogen content and combustible volatiles while having low ash content; the CaO / SiO2 value of the ash is also very high, indicating that the overall quality of lignite resources in Yunnan Province is good. Based on the characteristics of lignite resources, its price is much lower than that of anthracite, lean coal, and bituminous coal, making it significantly more economical. The high hydrogen content and combustible volatiles improve the smelting and reduction process in the blast furnace, and the increased penetration of hydrogen reducing gas is more conducive to airflow blowing into the center and activating the hearth. The high CaO and low SiO2 characteristics of lignite ash not only reduce slag volume under the same conditions, but also allow for the use of more acidic, emission-reducing, environmentally friendly, and lower-cost pellets with the same basicity of sinter. Furthermore, the large-scale feeding of titanium-containing sinter and pellets into the furnace, exceeding a certain load, easily leads to the formation of high-melting-point TiC, TiN, and Ti(C, N) suspended in the slag and iron, deteriorating slag fluidity and the smelting process within the furnace. Therefore, intensified smelting of vanadium-titanium magnetite often requires a higher oxygen potential. Importantly, due to its slag-forming characteristics, intensified smelting of vanadium-titanium magnetite is not conducive to increasing the coal ratio. A low coal ratio makes it difficult for the blast furnace to accept higher blast temperatures and oxygen enrichment rates, resulting in an imbalance of theoretical combustion temperatures, sometimes even requiring the use of humidified blast to achieve equilibrium. Meanwhile, lignite requires higher temperatures during decomposition, which complements the need for theoretical combustion temperature balance during intensified smelting of vanadium-titanium magnetite.

[0006] Existing methods for long-cycle intensified blast furnace smelting of vanadium-titanium magnetite still suffer from low blast furnace utilization, low pulverized coal injection ratio (below 140 kg / tFe), and high fuel costs. No literature reports on large-scale intensified blast furnace smelting using low-silicon, high-basicity vanadium-titanium sinter or low-silicon, high-titanium pellets, blended with 10%–35% lignite. For example, the blast furnace utilization rate in the medium and large blast furnaces of Chengde Iron and Steel in northern China, using vanadium-titanium magnetite for blast furnace smelting, is below 3.50 t / m³. 3However, a certain proportion of lignite co-injection has not yet been achieved; Shandong Iron and Steel has achieved a certain proportion of lignite injection, but it falls within the category of high-grade, low-slag ordinary ore smelting; Panzhihua Iron and Steel Group and Xichang New Area in Southwest China rely on their own vanadium-titanium magnetite mine resources and insist on strengthening the smelting of medium and large-sized high-vanadium-titanium magnetite, which also reflects low-grade characteristics, but blast furnace operation and indicators still have a low blast furnace utilization coefficient (<3.0t / (dm³)). 3 Characterized by low pulverized coal injection ratios (<130 kg / tFe), and the need for a certain proportion of lignite mixed injection, Chengde Iron & Steel and Panzhihua Iron & Steel rely on their own vanadium-titanium magnetite mines and high-quality coking coal resources within their territory, ensuring a relatively stable source of raw materials and fuels. Overall, most raw materials and fuels are characterized by a single source, high stability, and a high dependence on conventional high-quality resources, failing to demonstrate the high utilization coefficient (>3.65 t / (dm³)) of vanadium-titanium magnetite smelting. 3 The low overall grade of the coal entering the furnace and the coke ash content >13.5% are particularly advantageous for utilizing lignite resources that are inexpensive, have high hydrogen content and combustible volatiles, and low ash content, which are conducive to reduction and emission reduction within a certain range. It also helps to balance the theoretical combustion temperature, promote the combustion efficiency of pulverized coal, increase the oxygen enrichment rate and blast temperature, and ultimately improve the blast furnace utilization coefficient, increase the coal ratio, reduce the coke ratio, and reduce the cost of pulverized coal injection.

[0007] Therefore, based on the principles of resource utilization according to local conditions, emission reduction and cost reduction, and improving technical and economic indicators to enhance the core competitiveness of steel enterprises, it is necessary to develop a new blast furnace smelting method that can stably and on a large scale use local and surrounding low-silicon, low-grade, high-basicity vanadium-titanium sinter, low-silicon, high-titanium vanadium-titanium pellets, high-ash, and high-sulfur coke as raw materials for intensified smelting. This method should also utilize local and surrounding low-priced lignite resources with high hydrogen content and combustible volatile matter for blast furnace injection on a certain scale. This will continuously improve the blast furnace utilization coefficient, increase the mixed injection combustion efficiency and replacement ratio, and significantly reduce fuel costs, especially the cost of pulverized coal injection. Summary of the Invention

[0008] To further expand resource utilization and reduce pig iron costs, leverage the high cost-effectiveness and resource characteristics of local lignite mixed injection, improve the combustion efficiency and relative replacement ratio of pulverized coal, reduce air consumption per ton of iron, increase blast furnace utilization coefficient, and reduce fuel costs, especially pulverized coal costs, this invention provides a blast furnace smelting method that, in the large-scale intensification of blast furnace smelting using high-basicity sintered ore (made from low-silicon vanadium-titanium magnetite concentrate), low-silicon high-titanium pellets, and coke with high ash and sulfur content, utilizes a certain proportion of locally sourced and surrounding lignite resources with low prices, high hydrogen content, and high combustible volatile matter content. This method also improves smelting intensity, increases the pulverized coal injection ratio, reduces fuel costs, especially pulverized coal costs, and maintains long-term stable furnace operation, ultimately significantly reducing pig iron production costs. This achieves the goal of expanding the utilization of high-cost-effective fuel resources under vanadium-titanium ore smelting conditions, scalably utilizing a relatively single and stable pulverized coal resource for blast furnace injection, and achieving the effects of increased production and reduced costs.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a blast furnace smelting method for vanadium-titanium magnetite with lignite injection, characterized by comprising the following steps:

[0010] A. Feed the following ore, expressed as a percentage by mass, into the blast furnace:

[0011]

[0012] The sum of the above four types of minerals is 100%;

[0013] At the same time, high-ash coke and small-particle coke are added to the blast furnace;

[0014] At the same time, the following mixed pulverized coal is injected into the blast furnace:

[0015] Anthracite 60%–70%

[0016] Lean coal 5%–20%

[0017] Lignite 10-35%

[0018] The total amount of the above three types of pulverized coal is 100%.

[0019] B. Define the conditions for raw materials and fuels to be fed into the furnace:

[0020] The definition of the charge to the furnace is as follows: the ore batch weight is based on the ore batch weight (kg) and the furnace volume (m³). 3 The ratio is 30-35 kg / m³. 3 The dry basis coke load, calculated without small-particle coke, is 4.65 to 4.85, with a water content of 500 kg / batch of coke.

[0021] The mixed coal powder is defined as follows: volatile matter 10% to 20%, ash content 9% to 12%, fixed carbon content not less than 60%, ignition temperature not less than 450℃, fineness: the proportion of mixed coal powder of -200 mesh not less than 60%;

[0022] The slag and titanium load are defined as follows: slag basicity 1.08~1.12, titanium load 40.0~60.0kg / tFe, and the metallurgical properties of the selected coke are verified.

[0023] C. Smelting shall be carried out under the following conditions: hot blast pressure 0.30–0.37 MPa, pressure difference 0.5 times hot blast pressure ± 0.010 MPa, hot blast temperature 1180–1250℃, and furnace air volume 3100–3500 m³ / h. 3 / min, oxygen enrichment in the blower is 12500~13500m³ 3 / h, mixed pulverized coal injection rate 140~160kg / t iron, injection rate 26.0%~29.0%; theoretical material velocity 9 batches ± 0.5 batches; wind speed 250~260m / s;

[0024] D. During the smelting process, all powdered materials fed into the furnace shall be less than 1.50%;

[0025] Slag composition control: magnesium oxide 10.0%–11.5%, titanium oxide 15.0%–17.5%, aluminum oxide 11.0%–12.5%, slag basicity 1.08–1.12;

[0026] The reduction rates of major elements in pig iron are controlled as follows: [Si] reduction rate <3.0%; [Ti] reduction rate <8.0%.

[0027] Smelting control: furnace top temperature 100-200℃, blast temperature 1180-1250℃, oxygen enrichment rate 4.8-5.5%, permeability index 19000-22000 m³ / s. 3 / (min.MPa), theoretical combustion temperature 2390~2450℃, blast kinetic energy 16600~17500 kg.m / S, furnace gas volume 3700~4700 m³ / s 3 / min, furnace gas development index 68.0~75.0m / min, permeability resistance coefficient 8.0~9.5;

[0028] If the above conditions are met, continue smelting;

[0029] E. Slag and iron are tapped in parallel tapping mode, corresponding to a comprehensive ore grade of 52.8%–53.5% for the furnace, with a blast furnace utilization coefficient of 3.65–3.80 t / (m³). 3.d), fuel ratio 540-555 kg / tFe, pulverized coal injection rate 26.0%-29.0%, of which: lignite 10%-35%, pulverized coal injection replacement ratio >0.98, desulfurization coefficient >0.88, and air consumption per ton of iron decreases with the increase of lignite proportion; if the pulverized coal injection ratio is increased, the replacement ratio is not less than 0.98, and the cost reduction of pulverized coal injection is >2.0 yuan / tFe, then smelting continues.

[0030] The chemical composition of the low-silicon, high-alkalinity vanadium-titanium sinter, by mass percentage, includes: TFe 52.0–53.0%, FeO 8.30–9.50%, SiO2 5.5–6.5%, CaO 11.0–12.0%, MgO 2.50–3.00%, TiO2 1.00–1.60%, S 0.05–0.07%, Al2O3 2.00–2.50%, MnO 0.20–0.40%, with the balance being unavoidable impurities; particle size 20–40 mm, drum index >78%;

[0031] The particle size of the low-silicon, high-alkalinity vanadium-titanium sinter is 5-8 mm, and the rest are the same as those of the low-silicon, high-alkalinity vanadium-titanium sinter.

[0032] The chemical composition of the low-silicon, high-titanium vanadium-titanium pellets, by mass percentage, includes: TFe 53.0–54.0%, FeO 2.00–2.60%, SiO2 4.60–5.30%, CaO 0.5–1.50%, MgO 1.0–2.0%, TiO2 2.5–3.5%, S 0.005–0.015%, Al2O3 2.0–3.0%, MnO 0.20–0.50%, with the balance being unavoidable impurities; the particle size is 6 mm–19 mm, and the compressive strength is >2000 N / particle.

[0033] The chemical composition of the high-silica oxidizing pellets, by mass percentage, includes: TFe 58.5–61.0%, FeO 2.00–2.55%, SiO2 8.0–9.0%, CaO 1.0–1.20%, MgO 2.60–2.80%, TiO2 9.90–10.50%, S 0.005–0.015%, Al2O3 2.00–2.80%, MnO 0.05–0.15%, with the balance being unavoidable impurities; the particle size is 6 mm–19 mm, and the compressive strength is >2000 N / particle.

[0034] The chemical composition of the high-ash coke used, by mass percentage, includes: moisture 1.0–5.0%, C 84.0–86.0%, ash 13.5–14.2%, S 0.50–0.75%, volatile matter 0.50%–1.20%; the balance being unavoidable impurities; M40 88.0–90.0%, M10 4.0–5.0%; CRI 23.0–26.0%, CSR 66.0–70.0%; the coke ash composition, by mass percentage, includes: K2O 0.30%–0.65%, Na2O 0.30%–0.75%, Fe2O3 6.0–8.0%, SiO2 53.0–55.0%, CaO 2.0–3.0%, MgO 0.20–0.50%, Al2O3 22.0–25.0%, TiO2 1.0–2.0%, balance being unavoidable impurities;

[0035] The small-particle coke has a particle size of 10mm to 20mm, and the rest are the same as the high-ash coke.

[0036] The anthracite composition, by mass percentage, includes: moisture 1.0–2.0%, C 78.0–80.0%, V 7.5–9.5%, Ash 11.0–12.5%, S 0.55–0.75%, H 0.1–1.0%, with the balance being unavoidable impurities; the anthracite ash content, i.e., the Ash component, by mass percentage includes: K₂O 0.50–0.70%, Na₂O 0.40%–0.75%, Fe₂O₃ 7.50%–9.50%, SiO₂ 46.0–49.0%, CaO 5.0–6.5%, MgO 2.0–3.0%, Al₂O₃ 23.0–25.0%, TiO₂ 1.0–2.0%, with the balance being unavoidable impurities; the anthracite particle size is 2 mm–6 mm;

[0037] The lean coal composition by mass percentage includes: moisture 1.0–5.0%, C 70.0–75.0%, V 11.0–15.0%, Ash 11.0–13.5%, S 0.60–0.75%, H 0.5–1.5%, with the balance being unavoidable impurities; the lean coal ash composition, i.e., Ash component, by mass percentage includes: K₂O 0.40–0.70%, Na₂O 0.30%–0.55%, Fe₂O₃ 7.00%–9.00%, SiO₂ 48.0–53.0%, CaO 4.0–6.0%, MgO 5.0–8.0%, Al₂O₃ 22.0–28.0%, TiO₂ 1.0–2.0%, with the balance being unavoidable impurities; the lean coal particle size is 3 mm–9 mm.

[0038] The lignite composition, by mass percentage, includes: moisture 20.0–26.0%, C 35.0–40.0%, V 35.0–40.0%, Ash 5.0–10.0%, S 0.85–1.05%, H 3.0–6.0%, with the balance being unavoidable impurities and water of crystallization; the lignite ash content, i.e., the Ash component, by mass percentage includes: K₂O 0.01–0.10%, Na₂O 0.10%–0.30%, Fe₂O₃ 10.00%–13.00%, SiO₂ 3.0–8.0%, CaO 40.0–50.0%, MgO 4.0–8.0%, Al₂O₃ 23.0–26.0%, TiO₂ 0.1% to 1.0%, with the balance being unavoidable impurities; lignite particle size 3mm to 10mm, moisture content <10.0%, and ignition point not lower than 450℃;

[0039] The above three types of coal are fed into the pulverizing system, dried, and ground at medium speed under nitrogen protection. The resulting mixed coal powder has the following specifications: moisture 0.50%–0.80%, volatile matter 10%–20%, ash 9%–12%, fixed carbon content >60%, and fineness: the proportion of coal powder with a mesh size of -200 mesh is not less than 60%.

[0040] In step B, when defining the conditions for raw material and fuel entering the furnace, it is necessary to use the main matrix evaluation parameter requirements to evaluate the material distribution matrix as follows:

[0041] The number of coking rings is 9–11, and the number of ore rings is 7–10; the distance between the largest ore corner landing point and the furnace wall is 0.10–0.550 m; the distance between the smallest ore corner landing point and the center of the furnace throat is 1.6–2.2 mm; the ratio of the distance between the smallest ore corner landing point and the center to the radius of the furnace throat is 0.50–0.70; the edge load Fb is 4.5–5.5, where the edge load is the weight of the ore at the largest ore corner and ≥α. 矿 最大 The ratio of the weight of coke at the coke corner position; the central load Fz is 3.5-5.5, where the central load is: the weight of ore at the smallest ore corner position and ≤α 矿 最小 The ratio of the weight of coke at the coke angle position; the comprehensive angle difference between coke and ore is -1.50° to -0.10°, which is the ratio of the weighted average of the coke position angle and the number of coke rings at each position angle to the weighted average of the ore position angle and the number of ore rings at each position angle.

[0042] In step B, when the titanium load is defined and needs to be increased, it is advisable to maintain the titanium load within the upper limit of the defined range of 40.0-60.0 kg / tFe by increasing the proportion of low-silicon, high-titanium vanadium-titanium pellets and reducing the proportion of high-silicon, acidic, oxidizing vanadium-titanium pellets to 0. If the titanium load exceeds the upper limit of 60.0 kg / tFe, the TiO2 content in the sinter should be adjusted to maintain the titanium load and slag basicity within the defined range. If the titanium load reaches 40 kg / tFe or above, the lignite ratio should be increased according to the following proportions: when the titanium load is >40 kg / tFe, the pulverized coal injection ratio should not be less than 140 kg / t; when the titanium load is >50 kg / tFe, the pulverized coal injection ratio should not be less than 145 kg / t.

[0043] In step B, when verifying the metallurgical properties of the selected coke, the following conditions must be met: M40 is 87.0-90.0%, M10 is 4.0-5.0%, CRI is 22.0-26.0%, and CSR is 66.0-70.0%. If these conditions are met, the verification is passed, and smelting can proceed.

[0044] In step C, the following conditions should be met: when the titanium load is >40 kg / t Fe, the pulverized coal injection ratio should not be less than 140 kg / t; when the titanium load is >50 kg / t Fe, the pulverized coal injection ratio should not be less than 145 kg / t.

[0045] In step D, when the titanium load is >50 kg / tFe, the following conditions should be met: the theoretical combustion temperature should not exceed 2450℃, the reduction rate of [Si] in pig iron should be <3.0%, the reduction rate of [Ti] should be <8.0%, and the permeability resistance coefficient should not exceed 9.0. If these conditions are not met, the cause should be investigated, and the lignite ratio, coke load, air temperature, oxygen enrichment rate, and pulverized coal injection ratio should be adjusted. The theoretical combustion temperature (tFe) involved in step D should also be adjusted. 理 The calculation formula is:

[0046] t 理 =1563+t 风 ×0.794+fO2×100×40.3+k 混煤 ×m 混煤 -H2O 风 ×6

[0047] in:

[0048] t 风 The blast furnace hot blast temperature is ℃;

[0049] fO2 is the oxygen enrichment rate of blast furnace blast air, in percentage.

[0050] k 混煤 The theoretical combustion temperature reduction caused by the decomposition of 1 kg of pulverized coal injected into the blast furnace, with 1 ton of iron as the unit, is a negative value, ℃ / (kg / tFe);

[0051] m 混煤 The ratio of pulverized coal injected into the blast furnace is kg / tFe;

[0052] H2O 风 1m 3 Moisture content (atmospheric humidity) in blast furnace blast, g / m 3 .

[0053] In step E, if the following conditions are not met: the pulverized coal injection ratio is increased, the replacement ratio is not less than 0.98, and the cost reduction of pulverized coal injection is greater than 2.0 yuan / tFe, then the cause should be investigated, and the lignite ratio, coke load, oxygen enrichment rate, pulverized coal injection ratio, and slag basicity should be adjusted until the conditions of increasing the pulverized coal injection ratio, replacing ratio not less than 0.98, and cost reduction of pulverized coal injection is greater than 2.0 yuan / tFe are met, and smelting continues.

[0054] In step E, slag and iron tapping in parallel tapping mode means that there are always two tapping points tapping iron simultaneously for 5-10 minutes; fuel ratio refers to coke ratio plus mixed pulverized coal injection ratio; pulverized coal injection rate refers to mixed pulverized coal injection ratio divided by fuel ratio; and ton iron air consumption refers to the air volume consumed in smelting 1 ton of iron.

[0055] In step E, the cost reduction value of pulverized coal injection refers to the cost reduction value obtained by adding lignite to smelt 1 ton of iron using pulverized coal, calculated as follows:

[0056] The cost reduction of pulverized coal injection = coal ratio after using lignite × price of mixed pulverized coal containing lignite - coal ratio before using lignite × price of mixed pulverized coal without lignite.

[0057] The low-silicon, high-alkalinity vanadium-titanium sinter is obtained by sintering using the technical solution with application number 201811369753.4. The sintered ore is then screened with 50mm and 10mm screens to remove the portions >50mm and <10mm, resulting in a particle size of 10mm to 50mm. After entering the blast furnace trough, the sinter is further screened into the furnace by a double-layer high-efficiency vibrating screen with an upper layer of 6mm and a lower layer of 4mm.

[0058] The low-silicon, high-alkalinity vanadium-titanium small-particle-size sintered ore is obtained by screening the ore under the screen of the above-mentioned sintered ore bin using a double-layer high-efficiency vibrating screen with an upper layer of 8mm and a lower layer of 5mm, and then feeding it into the furnace.

[0059] The low-silicon, high-titanium vanadium-titanium pellets are produced by pelletizing low-grade, high-titanium Panzhihua vanadium-titanium magnetite concentrate through a vertical shaft furnace pelletizing process. The pellets with a particle size of 6mm to 19mm are then screened with 19mm and 6mm screens to remove the >19mm and <6mm portions, and then screened into the furnace by a double-layer high-efficiency vibrating screen with an upper 6mm and a lower 4mm.

[0060] The small-particle coke mentioned above is obtained by screening the coke dust under the coke bins entering the furnace using a double-layer high-efficiency vibrating screen with an upper layer of 20mm and a lower layer of 10mm, and then feeding it into the furnace.

[0061] In step A, the coke used is coke with high ash and sulfur content; the amount of coke is fixed and not adjusted in this invention.

[0062] In step A, the mixed coal powder used is a mixture of anthracite, lean coal, and lignite in a certain dry basis ratio, wherein the lignite ratio is 10%–35%; the raw anthracite and lean coal are obtained by sieving the portion >10mm through a 10mm sieve; the raw lignite is obtained by drying (or dehydrating) to a moisture content <10.0% before entering the pulverizing system, and then sieving the portion >20mm through a 20mm sieve. In step A of this invention, the mixed coal powder that can be directly injected is obtained by mixing according to a set dry basis ratio, entering the pulverizing system, drying, and grinding in a medium-speed mill under nitrogen protection. The composition of the mixed coal powder is obtained by theoretical calculation of the composition of each coal type.

[0063] This invention focuses on the stable and large-scale application of low-grade, high-basicity sintered ore, prepared from a high proportion of vanadium-titanium-bearing Panzhihua magnetite concentrate using corresponding patented technology, and cost-effective vanadium-titanium pellets prepared from Panzhihua vanadium-titanium concentrate, in blast furnaces. It also utilizes local and surrounding lignite resources, which offer excellent cost-effectiveness and low price. Under these conditions, the high hydrogen content and combustible volatiles of these resources are leveraged to improve the reduction process in the furnace and increase the penetration force at the center of the hearth, thereby improving the smoothness of blast furnace operation and activating the hearth. Furthermore, the fact that the decomposition of these resources requires higher temperatures helps to improve the oxygen enrichment rate, blast temperature, and other intensifying factors to balance the theoretical combustion temperature, thus contributing to increased blast furnace production, energy saving, and reduced consumption. Under the condition of utilizing lignite resources at a scale of 10% to 35%, new blast furnace smelting parameters and gas flow parameters were further explored, and corresponding blast furnace smelting technologies were developed. New matching relationships were established for technical indicators such as feed grade, pulverized coal injection ratio, relative replacement ratio, and air consumption per ton of iron in the intensified smelting production of vanadium-titanium magnetite. This ensured long-term and stable improvement of the main technical and economic indicators of blast furnace smelting, and a new formula for calculating the theoretical combustion temperature under mixed pulverized coal injection conditions was obtained. Furthermore, it facilitated stable operation in the vanadium-titanium ore smelting process, improved the blast furnace utilization coefficient, and increased the pulverized coal injection ratio, thereby forming a new economical blast furnace smelting method under lignite resource conditions, improving the technical and economic indicators of vanadium-titanium ore smelting blast furnaces, and reducing pig iron smelting costs.

[0064] This invention provides a high-intensity smelting method for vanadium-titanium magnetite using low-grade, low-silicon, high-alkalinity vanadium-titanium sinter and low-silicon, high-titanium pellets as ore raw materials, and coke with high ash content and mixed coal powder with 10% to 35% lignite as reducing agent and heating agent, thereby improving the blast furnace utilization coefficient, increasing the pulverized coal injection ratio, and reducing the cost of smelting, especially pulverized coal injection.

[0065] Compared with the prior art, the beneficial effects of this invention are as follows:

[0066] This invention, based on the fundamental theory of blast furnace ironmaking and combining actual blast furnace smelting parameters and gas flow evaluation parameters, develops corresponding blast furnace smelting technologies. It obtains new, suitable blast furnace operating parameters for enhanced blast furnace smelting using vanadium-titanium magnetite blended with locally sourced, inexpensive, and cost-effective lignite, improving the fuel structure and reducing costs. During the enhanced blast furnace smelting process, it can stably and on a large scale utilize locally sourced and surrounding low-silicon, low-grade, high-basicity vanadium-titanium sinter, low-silicon, high-titanium vanadium-titanium pellets, and high-ash, high-sulfur coke. A certain proportion of locally sourced and surrounding lignite resources, which are inexpensive and have high hydrogen content and combustible volatiles, are used. This continuously improves the blast furnace utilization coefficient, increases the efficiency of mixed injection combustion and the replacement ratio, significantly reducing fuel costs, especially pulverized coal costs, and expanding the use of lower-cost and energy-saving pellets. This achieves the goals of effectively increasing output, improving the pulverized coal injection ratio, and reducing smelting costs, especially fuel costs, thereby enhancing the core competitiveness of steel enterprises and improving energy conservation and emission reduction indicators.

[0067] Existing technologies fail to fully utilize the high utilization coefficient (>3.65t / (d.m3)) and low overall grade (<53.5%) of vanadium-titanium magnetite smelting, and the coke ash content is >13.5%, especially failing to achieve large-scale application of inexpensive lignite resources with high hydrogen content, high combustible volatile matter content, low ash content, and high CaO content for intensified smelting. This invention solves the problems of existing intensified smelting technologies for vanadium-titanium magnetite, such as the single source of raw materials and fuels, high dependence on conventional high-quality resources, low blast furnace utilization coefficient, low pulverized coal injection ratio, high fuel costs, and high air consumption per ton of iron. It effectively broadens the utilization ratio of local and surrounding resources and improves technical and economic indicators. Furthermore, it fully utilizes local and surrounding vanadium-titanium low-silicon magnetite concentrate, low-silicon medium-titanium high-vanadium acidic oxidizing pellets, and low-silicon high-titanium medium-vanadium acidic oxidizing vanadium-titanium pellets, as well as fuel resources with higher ash and sulfur content, especially inexpensive lignite resources with high hydrogen content and combustible volatile matter content from the local area and surrounding regions. This approach demonstrates the advantages of balancing theoretical combustion temperature, promoting pulverized coal combustion efficiency, increasing oxygen enrichment and blast temperature, ultimately improving blast furnace utilization, increasing coal ratio and reducing coke ratio, and lowering pulverized coal injection costs. A new matching relationship between blast furnace grade, pulverized coal injection ratio, relative replacement ratio, blast consumption per ton of iron, and technical indicators was established in the intensified smelting production of vanadium-titanium magnetite, resulting in long-term stable improvement of key technical and economic indicators in blast furnace smelting. A new formula for calculating theoretical combustion temperature under mixed pulverized coal injection conditions was also derived. This facilitates stable operation in vanadium-titanium ore smelting, improves blast furnace utilization, and increases the pulverized coal injection ratio, thus forming a new economical blast furnace smelting method under lignite resource conditions, improving the technical and economic indicators of vanadium-titanium ore smelting blast furnaces, and reducing pig iron smelting costs. A smelting method that utilizes vanadium-titanium magnetite with lignite to enhance smelting and reduce costs, without excluding the benefits gained from increasing the coal ratio and reducing the coke ratio, reduces the cost of pulverized coal injection by 2.55–11.51 yuan / ton by adding 10%–35% lignite; and reduces fixed cost amortization by 1.25%–3.75% by improving the blast furnace utilization coefficient. This method achieves both expanded resource utilization and reduced pig iron production costs under specific conditions. Detailed Implementation

[0068] The present invention will now be described in further detail with reference to the embodiments.

[0069] Those skilled in the art will understand that the following examples and 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.

[0070] Example 1

[0071] A blast furnace smelting method for vanadium-titanium magnetite with lignite injection includes the following steps:

[0072] A. The following mass ratio of ore:

[0073]

[0074] The sum of the above four types of minerals is 100%;

[0075] Coke with higher ash and sulfur content and small-particle coke are fed into the blast furnace in the usual amount.

[0076] At the same time, the following mixed pulverized coal is injected into the blast furnace:

[0077] 70% of anthracite

[0078] 20% lean coal

[0079] lignite 10%

[0080] The total amount of the above three types of pulverized coal is 100%.

[0081] The low-silicon, high-alkalinity vanadium-titanium sinter is produced by sintering self-produced ultrafine-grained concentrate (52.0% by mass) and low-grade vanadium-titanium magnetite concentrate (18.0% by mass) according to the technical scheme described in 201811369753.4. The sinter, with a particle size of 10mm to 50mm, is then sieved through a 50mm and a 10mm screen to remove particles >50mm and <10mm. This sinter then enters the blast furnace trough and is further screened by a double-layer high-efficiency vibrating screen (6mm upper layer, 4mm lower layer) before being fed into the furnace. Its chemical composition is as follows: Sinter: TFe 52.21%, FeO 9.01%, SiO2 5.71%, CaO 11.991%, MgO 2.63%, TiO2 1.369%, S 0.055%, Al2O3 2.11%, MnO 0.241%, with the following physical properties: ISO drum index 78.3%, average particle size 26.5 mm;

[0082] The low-silicon, high-alkalinity vanadium-titanium small-particle sinter is obtained by screening the ore under the screen of the above-mentioned sinter entering the furnace using a double-layer high-efficiency vibrating screen with an upper layer of 8mm and a lower layer of 5mm, and then feeding it into the furnace. Its chemical composition is the same as the above-mentioned sinter, with an average particle size of 6.3mm.

[0083] The low-silicon, high-titanium vanadium-titanium pellets are produced by refining pellets mainly composed of low-grade, high-titanium Panzhihua vanadium-titanium magnetite concentrate through a vertical shaft furnace pelletizing process. The pellets are then sieved with 19mm and 6mm screens to remove the >19mm and <6mm portions, resulting in pellets with a particle size of 6mm to 19mm. These pellets are then screened into the furnace using a double-layer high-efficiency vibrating screen with an upper 6mm and a lower 4mm layer. The chemical composition is as follows: TFe 53.39%, FeO 2.15%, SiO2 4.94%, CaO 1.33%, MgO 2.66%, TiO2 10.09%, S 0.007%, Al2O3 2.39%, MnO 0.29%, with an average particle size of 11.6mm and a compressive strength of 2217N / particle.

[0084] The coke composition is as follows: moisture 4.26%, C 85.630%, Ash 13.71%, S 0.635%, volatile matter 0.90%; the coke ash composition is as follows: K2O 0.55%, Na2O 0.58%, Fe2O3 7.35%, SiO2 54.35%, CaO 2.64%, MgO 0.46%, Al2O3 24.90%, TiO2 1.55%.

[0085] The selected metallurgical properties of the coke are: M40 89.20%, M10 4.55%; CRI 24.87%, CSR 67.59%;

[0086] The small-particle coke mentioned above is obtained by screening the coke dust under the coke bins of the furnace using a double-layer high-efficiency vibrating screen with an upper layer of 20mm and a lower layer of 10mm, and then feeding it into the furnace; the chemical composition is the same as described above.

[0087] The mixed coal powder is composed of anthracite, lean coal, and lignite mixed according to the aforementioned dry basis ratio, wherein the lignite ratio is 10%; the anthracite raw coal and lean coal raw coal are obtained by sieving the portion >10mm through a 10mm sieve; the lignite raw coal has a moisture content of 9.79% before entering the pulverizing system, and is then sieved with a 20mm sieve to remove the portion >20mm.

[0088] In the mixed pulverized coal:

[0089] The anthracite composition is as follows: moisture 1.49%, C 79.49%, V 8.00%, Ash 11.53%, S 0.68%, H 0.13%; the ash composition of the coal powder is as follows: K2O 0.53%, Na2O 0.60%, Fe2O3 8.76%, SiO2 47.25%, CaO 5.48%, MgO 2.42%, Al2O3 24.09%, TiO2 1.55%.

[0090] The lean coal composition is as follows: moisture 2.37%, C 73.56%, V 14.04%, Ash 12.28%, S 0.69%, H 0.68%; the ash composition of the coal powder is as follows: K2O 0.50%, Na2O 0.35%, Fe2O3 7.72%, SiO2 51.38%, CaO 4.67%, MgO 7.13%, Al2O3 24.49%, TiO2 1.46%.

[0091] The lignite composition is as follows: moisture 23.11%, C 37.01%, V 37.82%, Ash 8.16%, S 1.01%, H 4.06%; the ash composition of the coal powder is as follows: K2O 0.03%, Na2O 0.10%, Fe2O3 10.92%, SiO2 5.92%, CaO 46.66%, MgO 4.40%, Al2O3 24.25%, TiO2 0.41%.

[0092] After mixing the three types of coal, the mixture is fed into a pulverizing system, dried, and ground at medium speed under nitrogen protection. The resulting mixed coal powder has the following composition: C 74.06%, V 12.19%, Ash 9.03%, S 0.716%, H 0.63%; the ash content of the coal powder is: K2O 0.47%, Na2O 0.50%, Fe2O3 8.77%, SiO2 43.94%, CaO 9.43%, MgO 3.56%, Al2O3 24.19%, TiO2 1.42%; the ignition temperature is 562℃, and the fineness is -200 mesh, with a mixed coal powder content of 66.7%.

[0093] B. Define the conditions for raw material and fuel charging: The charging material must meet the following requirements: ore batch weight is 33,500 kg (ore batch (kg) and furnace volume (m³)). 3 The ratio is 31.02 kg / m³. 3 The dry basis coke batch is 7085 kg / batch, the dry basis coke briquettes are 479 kg / batch, and the dry basis coke load is 4.728 (excluding the dry basis coke briquettes of 479 kg / batch); it meets the matrix evaluation requirements. The slag ratio, slag basicity, and titanium load are as follows: slag ratio 472 kg / t, slag basicity 1.11, titanium load 44.45 kg / tFe, and pulverized coal injection ratio is 142.5 kg / t.

[0094] The fabric matrix is ​​evaluated as follows: 10 rings for coke and 9 rings for ore; the weight of coke per ring is 708.5 kg / ring, and the weight of ore per ring is 3722 kg / ring; L (maximum ore angle (α) 矿 最大 The distance between the ore drop point and the furnace wall is 0.306m; the minimum ore angle (α) 矿 最小The distance between the ore drop point and the center of the furnace throat is 1.786m; the ratio of the distance between the minimum ore angle drop point and the center to the furnace throat radius is 0.66; the edge load Fb (the weight of the ore at the maximum ore angle and ≥α) 矿 最大 The ratio of coke weight at the coke corner position is 4.89; the central load Fz (the ratio of ore weight at the minimum ore corner position to ≤α) is 4.89. 矿 最小 The ratio of coke weight at each coke angle position is 5.21; the comprehensive angle difference between coke and ore (the weighted average of the coke angle and the number of coke rings at each angle to the weighted average of the ore angle and the number of ore rings at each angle) is -0.73°.

[0095] If the above conditions are met, the verification is passed, and smelting continues;

[0096] C. Smelting is carried out under the following conditions: hot blast pressure is 0.313 MPa, pressure difference is 0.166 MPa, hot blast temperature is 1180℃, and furnace air volume is 3159 m³ / h. 3 / min, oxygen enrichment in the blower is 12500m³ / min. 3 / h, pulverized coal injection rate is 22800kg / h, pulverized coal ratio is 142.5kg / t iron, injection rate is 26.02%; theoretical material velocity is 8.88 batches; wind speed is 253m / s; when the titanium load is >40kg / tFe, the pulverized coal ratio is not less than 140kg / t, and smelting continues;

[0097] D. During the smelting process, the powder content of sintered ore entering the furnace is controlled at 0.92%, and the powder content of pelletized ore entering the furnace is controlled at 0.77%.

[0098] The following components are controlled in the slag: magnesium oxide 10.46%, titanium oxide 15.09%, aluminum oxide 11.07%, and slag basicity 1.11;

[0099] The reduction rates of the main elements in pig iron are controlled as follows: [Si] reduction rate 1.65%; [Ti] reduction rate 3.97%.

[0100] The remaining controls are as follows: furnace top temperature 162℃, air temperature 1180℃, oxygen enrichment rate 4.86%, and air permeability index 21433m. 3 / (min.MPa), theoretical combustion temperature 2396℃, blast kinetic energy 16849kg.m / s, furnace gas volume 3714m³ 3 / min, furnace gas development index 69.9m / min, permeability resistance coefficient 8.56;

[0101] Among them: the theoretical combustion temperature (t) involved 理 The calculation formula is:

[0102] t理 =1563+t 风 ×0.794+fO2×100×40.3+k 混煤 ×m 混煤 -H2O 风 ×6

[0103] in:

[0104] t 风 The blast furnace hot blast temperature is ℃;

[0105] fO2 is the oxygen enrichment rate of blast furnace blast air, in percentage.

[0106] k 混煤 The theoretical combustion temperature reduction caused by the decomposition of 1 kg of pulverized coal injected into the blast furnace, with 1 ton of iron as the unit, is a negative value, ℃ / (kg / tFe);

[0107] m 混煤 The ratio of pulverized coal injected into the blast furnace is kg / tFe;

[0108] H2O 风 1m 3 Moisture content (atmospheric humidity) in blast furnace blast, g / m 3 ;

[0109] In this example: k 混煤 The value is -1.60℃ / (kg / tFe); H2O 风 The local atmospheric humidity is 12 kg / m³. 3 ;

[0110] If the smelting conditions are met, continue smelting;

[0111] E. Slag and iron tapping are performed in parallel tapping mode: corresponding to a comprehensive feed grade of 52.923%, and a blast furnace utilization coefficient of 3.703 t / (m³). 3 .d) The coke ratio (including coke briquettes) decreased to 405.1 kg / tFe, the pulverized coal injection ratio was 142.5 kg / tFe, and the fuel ratio was 547.6 kg / tFe; the coal blending rate increased to 26.02%, of which: high-hydrogen, high-volatile, low-ash, low-price lignite accounted for 10%; during the smelting process, the pulverized coal injection replacement ratio was 0.99, the desulfurization coefficient was 0.891, and the air consumption per ton of iron decreased to 1138 m³. 3 / tFe; There are always two taps simultaneously producing iron for 8 minutes;

[0112] The above-mentioned blast furnace utilization coefficient, pulverized coal injection ratio, pulverized coal injection replacement ratio and pulverized coal injection rate, desulfurization coefficient and air consumption per ton of iron all meet the smelting requirements and have not affected the stable operation of the furnace.

[0113] F. Verify the smelting effect and cost of lignite-injected vanadium-titanium ore, as follows: increase the pellet ratio by 3.0%; reduce the slag ratio to 472 kg / tFe. At a titanium load of 44.45 kg / tFe, the pulverized coal injection ratio is 142.5 kg / t. If the pulverized coal injection ratio is increased, the replacement ratio is not less than 0.98, and the cost reduction of pulverized coal injection is 2.55 yuan / tFe, then smelting can continue.

[0114] Example 2

[0115] A blast furnace smelting method for vanadium-titanium magnetite with lignite injection includes the following steps:

[0116] A. The following mass ratio of ore:

[0117]

[0118] The total of the above four types of ore is 100%, and coke with higher ash and sulfur content and small particle size is fed into the blast furnace in the usual amount.

[0119] Simultaneously, mixed pulverized coal is injected into the blast furnace:

[0120] 60% of anthracite

[0121] 20% lean coal

[0122] 20% lignite

[0123] The total amount of the above three types of pulverized coal is 100%.

[0124] The low-silicon, high-alkalinity vanadium-titanium sinter is produced by sintering self-produced ultrafine-grained concentrate (52.0% by mass) and low-grade vanadium-titanium magnetite concentrate (18.0% by mass) according to the technical scheme described in 201811369753.4. The sinter, with a particle size of 10mm to 50mm, is then sieved through a 50mm and a 10mm screen to remove particles >50mm and <10mm. This sinter then enters the blast furnace trough and is further screened by a double-layer high-efficiency vibrating screen (6mm upper layer, 4mm lower layer) before being fed into the furnace. Its chemical composition is as follows: Sinter: TFe 52.50%, FeO 9.17%, SiO2 5.66%, CaO 11.886%, MgO 2.63%, TiO2 1.387%, S 0.06%, Al2O3 2.04%, MnO The content is 0.231%, and its physical properties are: ISO drum index 78.6%, average particle size 27.2 mm;

[0125] The low-silicon, high-alkalinity vanadium-titanium small-particle sinter is obtained by screening the returned ore from the ore bin of the above-mentioned sinter into the furnace using a double-layer high-efficiency vibrating screen with an upper layer of 8mm and a lower layer of 5mm, and then feeding it into the furnace; its chemical composition is the same as the above-mentioned sinter, with an average particle size of 6.8mm.

[0126] The low-silicon, high-titanium vanadium-titanium pellets are produced by using a vertical shaft furnace pelletizing process to process pellets mainly composed of low-grade, high-titanium Panzhihua vanadium-titanium magnetite concentrate. The pellets are then sieved with 19mm and 6mm screens to remove portions >19mm and <6mm, resulting in pellets with a particle size of 6mm to 19mm. These pellets are then fed into the furnace via a double-layer high-efficiency vibrating screen (6mm upper layer, 4mm lower layer). The chemical composition is as follows: TFe 53.58%, FeO 2.13%, SiO2 5.14%, CaO 1.23%, MgO 2.71%, TiO2 10.14%, S 0.009%, Al2O3 2.52%, MnO 0.27%; average particle size 11.9mm; compressive strength 2259N / particle.

[0127] The coke composition is as follows: moisture 4.38%, C 86.021%, Ash 13.60%, S 0.65%, volatile matter 0.87%; the coke ash composition is as follows: K2O 0.58%, Na2O 0.60%, Fe2O3 7.71%, SiO2 54.35%, CaO 2.82%, MgO 0.453%, Al2O3 23.27%, TiO2 1.57%.

[0128] The selected metallurgical properties of the coke are: M40 88.73%, M10 4.51%; CRI 24.09%, CSR 68.15%;

[0129] The small-particle coke mentioned above is obtained by screening the coke dust under the coke bins of the furnace using a double-layer high-efficiency vibrating screen with an upper layer of 20mm and a lower layer of 10mm, and then feeding it into the furnace; the chemical composition is the same as described above.

[0130] The mixed coal powder is composed of anthracite, lean coal, and lignite mixed according to the aforementioned dry basis ratio, wherein the lignite ratio is 20%; the anthracite raw coal and lean coal raw coal are obtained by sieving the portion >10mm through a 10mm sieve; the lignite raw coal has a moisture content of 9.26% before entering the pulverizing system, and is then sieved with a 20mm sieve to remove the portion >20mm.

[0131] In the mixed pulverized coal:

[0132] The anthracite composition is as follows: moisture 1.76%, C 79.94%, V 8.31%, Ash 11.13%, S 0.66%, H 0.11%; the ash composition of the coal powder is as follows: K2O 0.57%, Na2O 0.63%, Fe2O3 8.96%, SiO2 48.93%, CaO 5.58%, MgO 2.62%, Al2O3 24.89%, TiO2 1.51%.

[0133] The lean coal composition is as follows: moisture 2.85%, C 72.96%, V 14.63%, Ash 12.88%, S 0.67%, H 0.71%; the ash composition of the coal powder is as follows: K2O 0.54%, Na2O 0.39%, Fe2O3 8.03%, SiO2 50.58%, CaO 5.01%, MgO 7.83%, Al2O3 24.99%, TiO2 1.40%.

[0134] The lignite composition is as follows: moisture 21.2%, C 40.77%, V 40.02%, Ash 7.87%, S 1.03%, H 4.32%; the ash content of the coal powder is as follows: K2O 0.10%, Na2O 0.055%, Fe2O3 13.17%, SiO2 8.07%, CaO 42.29%, MgO 2.56%, Al2O3 27.2%, TiO2 0.52%.

[0135] After mixing the three types of coal, the mixture is fed into a pulverizing system, dried, and ground at medium speed under nitrogen protection. The resulting mixed coal powder has the following composition: C 70.56%, V 15.612%, Ash 8.63%, S 0.753%, H 1.07%; the ash content of the coal powder is: K2O 0.44%, Na2O 0.46%, Fe2O3 9.43%, SiO2 40.24%, CaO 12.68%, MgO 3.39%, Al2O3 20.79%, TiO2 1.33%; the ignition temperature is 530℃, and the fineness is -200 mesh, with a mixed coal powder content of 65.8%.

[0136] B. Define the conditions for raw material and fuel charging: The charging material must meet the following requirements: ore batch weight is 33,500 kg (ore batch (kg) and furnace volume (m³)). 3 The ratio is 31.02 kg / m³. 3 The dry basis coke batch is 7076 kg / batch, the dry basis coke briquettes are 478 kg / batch, and the dry basis coke load is 4.734 (excluding the dry coke briquettes of 479 kg / batch); it meets the matrix evaluation requirements. The slag ratio, slag basicity, and titanium load are as follows: slag ratio 468.2 kg / t; slag basicity 1.11 times; titanium load 50.81 kg / tFe; and pulverized coal injection ratio 142.5 kg / t.

[0137] The fabric matrix is ​​evaluated as follows: 10 rings for coke and 9 rings for ore; the weight of coke per ring is 707.6 kg / ring, and the weight of ore per ring is 3722 kg / ring; L (maximum ore angle (α) 矿 最大 The distance between the ore drop point and the furnace wall is 0.306m; the minimum ore angle (α) 矿 最小The distance between the ore drop point and the center of the furnace throat is 1.786m; the ratio of the distance between the minimum ore drop point and the center to the radius of the furnace throat is 0.66; Fb (edge ​​load (the weight of the ore at the maximum ore angle and ≥α) 矿 最大 The ratio of coke weight at the coke corner position is 4.89; Fz (center load (minimum ore weight at the ore corner position and ≤α) 矿 最小 The ratio of coke weight at the coke angle position is 5.21; the comprehensive angle difference between coke and ore (the weighted average of the coke angle and the number of coke rings at each angle to the weighted average of the ore angle and the number of ore rings at each angle) is -0.73°.

[0138] If the above conditions are met, the verification is passed, and smelting continues;

[0139] C. Smelting is carried out under the following conditions: hot blast pressure is 0.319 MPa, pressure difference is 0.166 MPa, hot blast temperature is 1200℃, and furnace air volume is 3183 m³ / h. 3 / min, oxygen enrichment in the blower is 13000m³ 3 / h, pulverized coal injection rate is 23900kg / h, coal ratio is 146.8kg / t iron, injection rate is 26.61%; theoretical material velocity is 9.05 batches; wind speed is 255m / s;

[0140] D. During the smelting process, the powder content of sintered ore fed into the furnace is controlled at 0.75%, and the powder content of pellets fed into the furnace is controlled at 0.81%.

[0141] Slag composition control: Magnesium oxide range: 10.87%, Titanium oxide range: 17.01%, Aluminum oxide range: 11.17%, Slag basicity: 1.11;

[0142] The reduction rates of major elements in pig iron are controlled as follows: [Si] reduction rate 2.25%; [Ti] reduction rate 4.71%.

[0143] The furnace top temperature is 169℃; the controlled air temperature is 1200℃, the oxygen enrichment rate is 5.00%, and the air permeability index is 21081m. 3 / (min.MPa), theoretical combustion temperature 2401℃, blast energy 17207kg.m / S; furnace gas volume 3802m³ 3 / min, furnace gas development index 71.6m / min; permeability resistance coefficient 8.54;

[0144] Among them: the theoretical combustion temperature (t) involved 理 The calculation formula is:

[0145] t 理 =1563+t 风×0.794+fO2×100×40.3+k 混煤 ×m 混煤 -H2O 风 ×6

[0146] in:

[0147] t 风 The blast furnace hot blast temperature is ℃;

[0148] fO2 is the oxygen enrichment rate of blast furnace blast air, in percentage.

[0149] k 混煤 The theoretical combustion temperature reduction caused by the decomposition of 1 kg of pulverized coal injected into the blast furnace, with 1 ton of iron as the unit, is a negative value, ℃ / (kg / tFe);

[0150] m 混煤 The ratio of pulverized coal injected into the blast furnace is kg / tFe;

[0151] H2O 风 1m 3 Moisture content (atmospheric humidity) in blast furnace blast, g / m 3 ;

[0152] In this example: k 混煤 The value is -1.67℃ / (kg / tFe); H2O 风 The local atmospheric humidity is 12 kg / m³. 3 ;

[0153] E. Slag and iron are tapped using a parallel tapping pattern. This corresponds to a comprehensive feed grade of 52.91% and a blast furnace utilization coefficient of 3.773 t / (m³). 3 .d), the coke ratio (including coke butane) decreased to 404.7 kg / tFe, the pulverized coal injection ratio was 146.8 kg / tFe, the fuel ratio was 551.4 kg / tFe, and the coal blending rate increased to 26.61%; among which, the proportion of high-hydrogen, high-volatile, low-ash, and low-price lignite was 20%; the pulverized coal injection replacement ratio during the smelting process was 1.017; the desulfurization coefficient was 0.905; and the air consumption per ton of iron decreased to 1125 m³. 3 / tFe; There are always two taps simultaneously producing iron for 7 minutes;

[0154] The blast furnace utilization coefficient, pulverized coal injection ratio, pulverized coal injection replacement ratio and pulverized coal injection rate, desulfurization coefficient and air consumption per ton of iron were verified and all achieved the desired effect without affecting the stable operation of the furnace.

[0155] F. Verify the smelting effect and cost of lignite-injected vanadium-titanium ore, as follows: increase the pellet ratio by 6.0%; reduce the slag ratio to 468.2 kg / tFe. At a titanium load of 50.81 kg / tFe, the pulverized coal injection ratio is 146.8 kg / t. Meeting the requirements of increasing the pulverized coal injection ratio, ensuring a replacement ratio of no less than 0.98, and reducing the cost of pulverized coal injection by 6.39 yuan / tFe, smelting can continue.

[0156] Example 3

[0157] A blast furnace smelting method for vanadium-titanium magnetite with lignite injection includes the following steps:

[0158] A. The following mass ratio of ore:

[0159]

[0160] The total of the above four types of ore is 100%, and coke with higher ash and sulfur content and small particle size is fed into the blast furnace in the usual amount.

[0161] Simultaneously, mixed pulverized coal is injected into the blast furnace:

[0162] 60% of anthracite

[0163] 10% lean coal

[0164] Lignite 30%

[0165] The total amount of the above three types of pulverized coal is 100%.

[0166] The low-silicon, high-alkalinity vanadium-titanium sinter is produced by sintering self-produced ultrafine concentrate (54.0% by mass) and low-grade vanadium-titanium magnetite concentrate (16.0% by mass) according to the technical scheme described in 201811369753.4. The sinter, with a particle size of 10mm to 50mm, is then sieved through a 50mm and a 10mm screen to remove particles >50mm and <10mm. This sinter then enters the blast furnace trough and is further screened by a double-layer high-efficiency vibrating screen (6mm upper layer, 4mm lower layer) before being fed into the furnace. Its chemical composition is as follows: Sinter: TFe 52.78%, FeO 9.55%, SiO2 5.61%, CaO 11.802%, MgO 2.69%, TiO2 1.283%, S 0.046%, Al2O3 2.14%, MnO 0.25%. Its physical properties are: ISO drum index 79.2%, average particle size 28.6 mm;

[0167] The low-silicon, high-alkalinity vanadium-titanium small-particle sinter is obtained by screening the returned ore from the ore bin of the above-mentioned sinter into the furnace using a double-layer high-efficiency vibrating screen with an upper layer of 8mm and a lower layer of 5mm, and then feeding it into the furnace; its chemical composition is the same as the above-mentioned sinter, with an average particle size of 7.0mm.

[0168] The low-silicon, high-titanium vanadium-titanium pellets are produced by a vertical shaft furnace pelletizing process from pellets mainly composed of low-grade, high-titanium Panzhihua vanadium-titanium magnetite concentrate. The pellets are then sieved through a 19mm and a 6mm screen to remove particles >19mm and <6mm, resulting in pellets with a particle size of 6mm to 19mm. These pellets are then further screened into the furnace using a double-layer high-efficiency vibrating screen (6mm upper layer, 4mm lower layer). The chemical composition is as follows: TFe 53.98%, FeO 2.29%, SiO2 5.35%, CaO 1.29%, MgO 2.60%, TiO2 10.22%, S 0.009%, Al2O3 2.42%, MnO 0.23%, with an average particle size of 11.2mm and a compressive strength of 2273 N / particle.

[0169] The coke composition is as follows: moisture 4.17%, C 86.72%, Ash 13.78%, S 0.69%, volatile matter 0.89%; the coke ash composition is as follows: K2O 0.53%, Na2O 0.59%, Fe2O3 7.39%, SiO2 55.21%, CaO 2.54%, MgO 0.44%, Al2O3 23.88%, TiO2 1.55%.

[0170] The selected metallurgical properties of the coke are: M40 88.01%, M10 4.69%; CRI 23.69%, CSR 68.85%;

[0171] The small-particle coke mentioned above is obtained by screening the coke dust under the coke bins of the furnace using a double-layer high-efficiency vibrating screen with an upper layer of 20mm and a lower layer of 10mm, and then feeding it into the furnace; the chemical composition is the same as described above.

[0172] The mixed coal powder is composed of anthracite, lean coal, and lignite mixed according to the aforementioned dry basis ratio, wherein the lignite ratio is 30%; the anthracite raw coal and lean coal raw coal are obtained by sieving the portion >10mm through a 10mm sieve; the lignite raw coal has a moisture content of 9.26% before entering the pulverizing system, and is then sieved with a 20mm sieve to remove the portion >20mm.

[0173] In the mixed pulverized coal:

[0174] The anthracite composition is as follows: moisture 1.89%, C 78.65%, V 8.19%, Ash 12.02%, S 0.72%, H 0.15%; the ash composition of the coal powder is as follows: K2O 0.60%, Na2O 0.65%, Fe2O3 8.37%, SiO2 47.63%, CaO 5.29%, MgO 2.59%, Al2O3 23.93%, TiO2 1.54%.

[0175] The lean coal composition is as follows: moisture 1.97%, C 72.91%, V 14.55%, Ash 12.02%, S 0.72%, H 0.59%; the coal powder ash composition is as follows: K2O 0.50%, Na2O 0.71%, Fe2O3 8.54%, SiO2 52.08%, CaO 5.23%, MgO 6.99%, Al2O3 24.09%, TiO2 1.43%.

[0176] The lignite composition is as follows: moisture 22.155%, C 38.89%, V 38.92%, Ash 8.015%, S 1.02%, H 4.19%; the ash composition of the coal powder is as follows: K2O 0.133%, Na2O 0.075%, Fe2O3 12.37%, SiO2 7.055%, CaO 43.97%, MgO 3.51%, Al2O3 25.27%, TiO2 0.561%.

[0177] After mixing the three types of coal, the mixture is fed into a pulverizing system, dried, and ground at medium speed under nitrogen protection. The resulting mixed coal powder has the following composition: C 66.15%, V 18.045%, Ash 9.54%, S 0.756%, H 1.41%; the ash content of the coal powder is: K2O 0.41%, Na2O 0.42%, Fe2O3 9.64%, SiO2 35.58%, CaO 17.09%, MgO 3.21%, Al2O3 18.62%, TiO2 1.22%; the ignition temperature is 512℃, and the fineness (-200 mesh) is 63.7%.

[0178] B. Define the conditions for raw material and fuel charging: The charging material must meet the following requirements: ore batch weight is 33,800 kg (ore batch (kg) and furnace volume (m³)). 3 The ratio is 31.296 kg / m³. 3 The dry basis coke batch is 7091 kg / batch, the dry basis coke briquettes are 479 kg / batch, and the dry basis coke load is 4.77 (excluding the 479 kg / batch of dry coke briquettes); it meets the matrix evaluation requirements. The slag ratio, slag basicity, and titanium load are: slag ratio 468.9 kg / t; slag basicity 1.11 times; titanium load 50.46 kg / t; and Fe pulverized coal injection ratio 142.5 kg / t.

[0179] The fabric matrix is ​​evaluated as follows: 10 rings for coke and 9 rings for ore; the weight of coke per ring is 709.1 kg / ring, and the weight of ore per ring is 3755 kg / ring; L (maximum ore angle (α) 矿 最大 The distance between the ore drop point and the furnace wall is 0.369m; the minimum ore angle (α) 矿 最小The distance between the ore drop point and the center of the furnace throat is 1.680m; the ratio of the distance between the minimum ore drop point and the center to the radius of the furnace throat is 0.60; Fb (edge ​​load (the weight of the ore at the maximum ore angle and ≥α) 矿 最大 The ratio of coke weight at the coke corner position is 4.81; Fz (center load (minimum ore weight at the ore corner position and ≤α) 矿 最小 The ratio of coke weight at the coke angle position is 5.33; the comprehensive angle difference between coke and ore (the weighted average of the coke angle and the number of coke rings at each angle to the weighted average of the ore angle and the number of ore rings at each angle) is -0.43°.

[0180] C. Smelting is carried out under the following conditions: hot blast pressure is 0.320 MPa, pressure difference is 0.170 MPa, hot blast temperature is 1230℃, and furnace air volume is 3161 m³ / h. 3 / min, the oxygen enrichment in the blower is 13300m³ / min. 3 The coal powder injection rate is 25300 kg / h, the coal ratio is 152.6 kg / t iron, the injection rate is 27.59%, the theoretical material velocity is 9.02 batches, and the air velocity is 254 m / s.

[0181] D. During the smelting process, the powder content of sintered ore fed into the furnace is controlled at 0.65%, and the powder content of pelletized ore fed into the furnace is controlled at 0.71%.

[0182] Slag composition control: Magnesium oxide range: 10.87%, Titanium oxide range: 17.01%, Aluminum oxide range: 11.17%, Slag basicity: 1.11;

[0183] The reduction rates of major elements in pig iron are controlled as follows: [Si] reduction rate 2.73%; [Ti] reduction rate 6.35%.

[0184] The furnace top temperature is 161℃; the controlled air temperature is 1230℃, the oxygen enrichment rate is 5.14%, and the air permeability index is 21046m. 3 / (min.MPa), theoretical combustion temperature 2410℃, blast energy 17454kg.m / s; furnace gas volume 3885m³ 3 / min, furnace gas development index 73.2m / min; permeability resistance coefficient 8.22;

[0185] Among them: the theoretical combustion temperature (t) involved 理 The calculation formula is:

[0186] t 理 =1563+t 风 ×0.794+fO2×100×40.3+k 混煤 ×m 混煤 -H2O风 ×6

[0187] in:

[0188] t 风 The blast furnace hot blast temperature is ℃;

[0189] fO2 is the oxygen enrichment rate of blast furnace blast air, in percentage.

[0190] k 混煤 The theoretical combustion temperature reduction caused by the decomposition of 1 kg of pulverized coal injected into the blast furnace, with 1 ton of iron as the unit, is a negative value, ℃ / (kg / tFe);

[0191] m 混煤 The ratio of pulverized coal injected into the blast furnace is kg / tFe;

[0192] H2O 风 1m 3 Moisture content (atmospheric humidity) in blast furnace blast, g / m 3 ;

[0193] In this example: k 混煤 The value is -1.73℃ / (kg / tFe); H2O 风 The local atmospheric humidity is 12 kg / m³. 3 ;

[0194] E. Slag and iron tapping are performed in parallel tapping mode: corresponding to a comprehensive feed grade of 53.084%, and a blast furnace utilization coefficient of 3.795t / (m³). 3 .d) The coke ratio (including coke briquettes) decreased to 400.6 kg / tFe, the pulverized coal injection ratio was 152.6 kg / tFe, the fuel ratio was 553.3 kg / tFe, and the coal blending rate increased to 27.59%; among which, the proportion of high-hydrogen, high-volatile, low-ash, and low-price lignite was 30%; the pulverized coal injection replacement ratio during the smelting process was 1.031; the desulfurization coefficient was 0.910; and the air consumption per ton of iron decreased to 1111 m³. 3 / tFe; There are always two taps simultaneously producing iron for 7 minutes;

[0195] The blast furnace utilization coefficient, pulverized coal injection ratio, pulverized coal injection replacement ratio and pulverized coal injection rate, desulfurization coefficient and air consumption per ton of iron were verified and all achieved the desired effect without affecting the stable operation of the furnace.

[0196] F. Verify the smelting effect and cost of lignite-injected vanadium-titanium ore, as follows: increase the pellet ratio by 6.0%; reduce the slag ratio to 468.9 kg / tFe. When the titanium load is 50.46 kg / tFe, the pulverized coal injection ratio is 152.6 kg / t; the pulverized coal injection ratio is increased, the replacement ratio is not less than 0.98; the cost reduction of pulverized coal injection is 10.61 yuan / tFe, and smelting continues.

[0197] Example 4

[0198] A blast furnace smelting method for vanadium-titanium magnetite with lignite injection includes the following steps:

[0199] A. The following mass ratio of ore:

[0200]

[0201] The total of the above four types of ore is 100%, and coke with higher ash and sulfur content and small particle size is fed into the blast furnace in the usual amount.

[0202] Simultaneously, mixed pulverized coal is injected into the blast furnace:

[0203] 60% of anthracite

[0204] 5% lean coal

[0205] Lignite 35%

[0206] The total amount of the above three types of pulverized coal is 100%.

[0207] The low-silicon, high-alkalinity vanadium-titanium sinter is produced by sintering self-produced ultrafine concentrate (54.0% by mass) and low-grade vanadium-titanium magnetite concentrate (16.0% by mass) according to the technical scheme 201811369753.4. The sinter, with a particle size of 10mm to 50mm, is obtained by sieving the >50mm and <10mm portions using a 50mm and a 10mm screen. This sinter then enters the blast furnace trough and is further screened by a double-layer high-efficiency vibrating screen (6mm upper layer, 4mm lower layer) before being fed into the furnace. Its chemical composition is as follows: Sinter: TFe 52.96%, FeO 9.34%, SiO2 5.59%, CaO 11.739%, MgO 2.76%, TiO2 1.231%, S 0.043%, Al2O3 2.22%, MnO 0.22%. Its physical properties are: ISO drum index 78.9%, average particle size 28.1 mm;

[0208] The low-silicon, high-alkalinity vanadium-titanium small-particle sinter is obtained by screening the returned ore under the ore bin of the above-mentioned sinter into the furnace using a double-layer high-efficiency vibrating screen with an upper layer of 8mm and a lower layer of 5mm, and then feeding it into the furnace; its chemical composition is the same as the above-mentioned sinter, with an average particle size of 6.6mm.

[0209] The low-silicon, high-titanium vanadium-titanium pellets are produced by refining pellets mainly composed of low-grade, high-titanium Panzhihua vanadium-titanium magnetite concentrate through a vertical shaft furnace pelletizing process. The pellets are then sieved with 19mm and 6mm screens to remove the >19mm and <6mm portions, resulting in pellets with a particle size of 6mm to 19mm. These pellets are then screened into the furnace using a double-layer high-efficiency vibrating screen with an upper 6mm and a lower 4mm layer. The chemical composition is as follows: TFe 53.47%, FeO 2.31%, SiO2 5.22%, CaO 1.20%, MgO 2.55%, TiO2 10.09%, S 0.007%, Al2O3 2.37%, MnO 0.24%, with an average particle size of 10.89mm and a compressive strength of 2243N / particle.

[0210] The coke composition is as follows: moisture 4.20%, C 86.10%, Ash 13.58%, S 0.64%, volatile matter 0.78%; the coke ash composition is as follows: K2O 0.55%, Na2O 0.63%, Fe2O3 7.93%, SiO2 56.01%, CaO 2.76%, MgO 0.40%, Al2O3 22.93%, TiO2 1.55%.

[0211] The selected metallurgical properties of coke are: M40 88.58%, M10 4.91%; CRI 23.01%, CSR 68.03%;

[0212] The small-particle coke mentioned above is obtained by screening the coke dust under the coke bins of the furnace using a double-layer high-efficiency vibrating screen with an upper layer of 20mm and a lower layer of 10mm, and then feeding it into the furnace; the chemical composition is the same as described above.

[0213] The mixed coal powder is composed of anthracite, lean coal, and lignite mixed according to the aforementioned dry basis ratio, wherein the lignite ratio is 35%; the anthracite raw coal and lean coal raw coal are obtained by sieving the portion >10mm through a 10mm sieve; the lignite raw coal has a moisture content of 9.26% before entering the pulverizing system, and is then sieved with a 20mm sieve to remove the portion >20mm.

[0214] In the mixed pulverized coal:

[0215] The anthracite composition is as follows: moisture 1.55%, C 78.73%, V 8.07%, Ash 10.98%, S 0.63%, H 0.14%; the ash composition of the coal powder is as follows: K2O 0.56%, Na2O 0.61%, Fe2O3 9.04%, SiO2 48.99%, CaO 5.876%, MgO 2.44%, Al2O3 22.99%, TiO2 1.55%.

[0216] The lean coal composition is as follows: moisture 1.88%, C 72.07%, V 14.86%, Ash 12.54%, S 0.67%, H 0.72%; the ash composition of the coal powder is as follows: K2O 0.49%, Na2O 0.30%, Fe2O3 8.01%, SiO2 52.44%, CaO 5.01%, MgO 7.75%, Al2O3 23.84%, TiO2 1.45%.

[0217] The lignite composition is as follows: moisture 21.54%, C 40.21%, V 39.57%, Ash 8.21%, S 1.00%, H 4.44%; the ash content of the coal powder is as follows: K2O 0.123%, Na2O 0.055%, Fe2O3 11.897%, SiO2 7.05%, CaO 45.91%, MgO 3.99%, Al2O3 22.73%, TiO2 0.463%.

[0218] After mixing the three types of coal, the mixture is fed into a pulverizing system, dried, and ground at medium speed under nitrogen protection. The resulting mixed coal powder has the following composition: C 64.92%, V 19.495%, Ash 9.50%, S 0.762%, H 1.67%; the ash content of the coal powder is: K2O 0.40%, Na2O 0.40%, Fe2O3 9.99%, SiO2 34.48%, CaO 19.84%, MgO 3.25%, Al2O3 19.94%, TiO2 1.17%; the ignition temperature is 503℃, and the fineness (-200 mesh) is 65.1%.

[0219] B. Define the conditions for raw material and fuel charging: The charging material must meet the following requirements: ore batch weight is 33,800 kg (ore batch (kg) and furnace volume (m³)). 3 The ratio is 31.296 kg / m³. 3 The dry basis coke batch is 7091 kg / batch, the dry basis coke briquettes are 479 kg / batch, and the dry basis coke load is 4.77 (excluding the 479 kg / batch of dry coke briquettes); it meets the matrix evaluation requirements. The slag ratio, slag basicity, and titanium load are as follows: slag ratio 467.8 kg / t; slag basicity 1.11 times; titanium load 50.35 kg / tFe; and pulverized coal injection ratio 142.5 kg / t.

[0220] The fabric matrix is ​​evaluated as follows: 10 rings for coke and 9 rings for ore; the weight of coke per ring is 709.1 kg / ring, and the weight of ore per ring is 3755 kg / ring; L (maximum ore angle (α) 矿 最大 The distance between the ore drop point and the furnace wall is 0.369m; the minimum ore angle (α) 矿 最小The distance between the ore drop point and the center of the furnace throat is 1.680m; the ratio of the distance between the minimum ore drop point and the center to the radius of the furnace throat is 0.60; Fb (edge ​​load (the weight of the ore at the maximum ore angle and ≥α) 矿 最大 The ratio of coke weight at the coke corner position is 4.81; Fz (center load (minimum ore weight at the ore corner position and ≤α) 矿 最小 The ratio of coke weight at the coke angle position is 5.33; the comprehensive angle difference between coke and ore (the weighted average of the coke angle and the number of coke rings at each angle to the weighted average of the ore angle and the number of ore rings at each angle) is -0.43°.

[0221] C. Smelting is carried out under the following conditions: hot blast pressure is 0.320 MPa, pressure difference is 0.170 MPa, hot blast temperature is 1250℃, and furnace air volume is 3144 m³ / h. 3 / min, oxygen enrichment in the blower is 13500m³ / min. 3 / h, pulverized coal injection rate is 25900kg / h, coal ratio is 154.5kg / t iron, injection rate is 27.88%; theoretical material velocity is 8.96 batches; wind speed is 250m / s;

[0222] D. During the smelting process, the powder content of sintered ore fed into the furnace is controlled at 0.85%, and the powder content of pelletized ore fed into the furnace is controlled at 0.71%.

[0223] Slag composition control: Magnesium oxide range: 11.15%, Titanium oxide range: 16.52%; Aluminum oxide range: 11.45%; Slag basicity: 1.11;

[0224] The reduction rates of major elements in pig iron are controlled as follows: [Si] reduction rate 2.65%; [Ti] reduction rate 7.37%.

[0225] The furnace top temperature is 167℃; the controlled air temperature is 1250℃, the oxygen enrichment rate is 5.24%, and the air permeability index is 20682m. 3 / (min.MPa), theoretical combustion temperature 2422℃, blast energy 17219kg.m / s; furnace gas volume 3965m³ 3 / min, furnace gas development index 74.7m / min; permeability resistance coefficient 8.13;

[0226] Among them: the theoretical combustion temperature (t) involved 理 The calculation formula is:

[0227] t 理 =1563+t 风 ×0.794+fO2×100×40.3+k 混煤 ×m 混煤 -H2O风 ×6

[0228] in:

[0229] t 风 The blast furnace hot blast temperature is ℃;

[0230] fO2 is the oxygen enrichment rate of blast furnace blast air, in percentage.

[0231] k 混煤 The theoretical combustion temperature reduction caused by the decomposition of 1 kg of pulverized coal injected into the blast furnace, with 1 ton of iron as the unit, is a negative value, ℃ / (kg / tFe);

[0232] m 混煤 The ratio of pulverized coal injected into the blast furnace is kg / tFe;

[0233] H2O 风 1m 3 Moisture content (atmospheric humidity) in blast furnace blast, g / m 3 ;

[0234] In this example: k 混煤 The value is taken as -1.77℃ / (kg / tFe); H2O 风 The local atmospheric humidity is 12 kg / m³. 3 ;

[0235] E. Slag and iron tapping are carried out in parallel tapping mode: corresponding to a comprehensive feed grade of 53.20%, and a blast furnace utilization coefficient of 3.790 t / (m³). 3 .d) The coke ratio (including coke nitrate) decreased to 399.8 kg / tFe, the pulverized coal injection ratio was 154.5 kg / tFe, and the fuel ratio was 554.3 kg / tFe; the coal blending rate increased to 27.88%; of which, the proportion of high-hydrogen, high-volatile, low-ash, and low-priced lignite was 35%; the pulverized coal injection replacement ratio during the smelting process was 1.038; the desulfurization coefficient was 0.915; and the air consumption per ton of iron decreased to 1106 m³. 3 / tFe; There are always two taps simultaneously producing iron for 10 minutes;

[0236] The blast furnace utilization coefficient, pulverized coal injection ratio, pulverized coal injection replacement ratio and pulverized coal injection rate, desulfurization coefficient and air consumption per ton of iron were verified and all achieved the desired effect without affecting the stable operation of the furnace.

[0237] F. Verification of the smelting effect and cost of lignite-injected vanadium-titanium ore: The results were as follows: increasing the pellet ratio by 6.0%; reducing the slag ratio to 467.1 kg / tFe; and achieving a pulverized coal injection ratio of 154.5 kg / t when the titanium load was 50.35 kg / tFe. This met the requirements of increasing the pulverized coal injection ratio and ensuring a replacement ratio of no less than 0.98. The cost reduction of pulverized coal injection was 11.51 yuan / tFe, allowing for continued smelting.

[0238] To demonstrate the effectiveness of the present invention, conventional blast furnace smelting is used as a benchmark example. The smelting method of the benchmark example is conventional and will not be described in detail here. Only the relevant data of the benchmark example are given for comparison with embodiments 1-4 of this application. See the appendix and continued tables for details.

[0239] Appendix: Summary Table of Raw Material Structure, Parameters, and Benefits of Pulverized Lignite

[0240]

[0241] Continued table

[0242]

[0243] As shown in the attached table, compared to the baseline example, Examples 1-4 significantly increased the pulverized coal ratio and decreased the coke ratio by adding different proportions of lignite. Lignite demonstrated a significant price advantage, reducing the coal cost per ton of iron by RMB 2.55 / t to RMB 11.51 / t. Furthermore, it facilitated increased titanium load in blast furnace vanadium-titanium smelting. With the continuous increase in the coal ratio, the relative replacement ratio remained high (>0.98) as the lignite proportion increased, enhancing factors such as oxygen enrichment and blast temperature. This improved blast furnace operation, increased the desulfurization coefficient, significantly reduced permeability resistance, and increased the blast furnace utilization coefficient by 1.26% to 3.77%, correspondingly reducing (averaging out) the fixed costs per ton of iron smelting. In addition, it significantly reduced blast consumption per ton of iron, saving metallurgical energy consumption.

[0244] 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.

Claims

1. A blast furnace smelting method of vanadium titano-magnetite with addition of lignite injection, characterized in that, It comprises the following steps: A. The following mass percentage of ore is fed into the blast furnace: Low-silicon high-alkalinity vanadium-titanium sinter 60~66% Low-silicon high-alkalinity vanadium-titanium small particle size sinter 2% Low-silicon high-titanium vanadium-titanium pellet 30~38% High-silicon acidic oxidizing pellet 0~5% The total of the above four kinds of ore is 100%; At the same time, high-ash content coke and small particle size coke are added into the blast furnace; At the same time, the following mixed coal powder is injected into the blast furnace: Anthracite 60~70% Lean coal 5~20% Lignite 10~35% The total of the above three coal powders is 100%; B. The conditions of the raw materials entering the furnace are defined as follows: The definition of the charge to the furnace is as follows: the ore batch weight is based on the ore batch weight (kg) and the furnace volume (m³). 3 The ratio is 30~35 kg / m³. 3 The dry basis coke load, calculated without small-particle coke, is 4.65~4.85, with a water content of 500 kg / batch of coke. The mixed coal powder is defined as follows: volatile matter 10~20%, ash content 9~12%, fixed carbon content not less than 60%, ignition point temperature not less than 450℃, fineness: the proportion of -200 mesh mixed coal powder not less than 60%; The slag and titanium load are defined as follows: slag alkalinity 1.08~1.12, titanium load 40.0~60.0 kg / tFe, and the metallurgical properties of the selected coke are checked; C. smelting is carried out under the following conditions: hot blast pressure 0.30-0.37 MPa, pressure difference 0.5 times hot blast pressure ± 0.010 MPa, hot blast temperature 1180-1250℃, blast volume into the furnace 3100-3500 m 3 / min, oxygen enrichment in blast air 12500-13500 m 3 / h, mixed pulverized coal injection amount 140-160 kg / t of iron, injection rate 26.0-29.0%; theoretical material speed 9 batches ± 0.5 batches; air speed 250-260 m / s; D. During the smelting process, the powder of all the materials entering the furnace is less than 1.50%; In the slag, the following is controlled: magnesium oxide 10.0~11.5%, titanium oxide 15.0~17.5%, aluminum oxide 11.0~12.5%, slag alkalinity 1.08~1.12; In the pig iron, the reduction rate of the main elements is controlled as follows: [Si] reduction rate <3.0%; [Ti] reduction rate <8.0%; Smelting control: top temperature 100~200℃, blast temperature 1180~1250℃, oxygen enrichment rate 4.8~5.5%, permeability index 19000~22000m 3 (min.MPa), theoretical combustion temperature 2390~2450℃, blast kinetic energy 16600~17500kg.m / S, furnace-belly gas amount 3700~4700m 3 / min, furnace-belly gas development index 68.0~75.0m / min, permeability resistance coefficient 8.0~9.5; If the above conditions are met, the smelting continues; E, according to the parallel tapping mode, the slag and iron are tapped, corresponding to the comprehensive ore grade of 52.8%~53.5% into the furnace, the control: the utilization coefficient of blast furnace is 3.65~3.80t / (m 3 .d), the fuel ratio is 540~555kg / tFe, the coal injection rate is 26.0~29.0%, wherein: the lignite is 10~35%, the coal powder injection replacement ratio is >0.98, the desulfurization coefficient is >0.88, the air consumption per ton of iron decreases with the increase of the lignite proportion; if the coal injection ratio is increased, the replacement ratio is not less than 0.98, and the cost reduction value of the injected coal powder is >2.0 yuan / tFe, then the smelting is continued; In step B, when the conditions of the raw materials entering the furnace are defined, the following requirements for the main matrix evaluation parameters need to be used to evaluate and define the material matrix: 9-11 coke rings, 7-10 ore rings; the distance between the maximum ore angle and the furnace wall is 0.10-0.55 m; the distance between the minimum ore angle and the center of the furnace throat is 1.6-2.2 mm; the ratio of the distance between the minimum ore angle and the center to the radius of the furnace throat is 0.50-0.70; the edge load Fb is 4.5-5.5, the edge load being the ratio of the weight of the ore at the maximum ore angle to the weight of the coke at the coke angle 矿 最大 ≥ α; the center load Fz is 3.5-5.5, the center load being the ratio of the weight of the ore at the minimum ore angle to the weight of the coke at the coke angle 矿 最小 ≤ α; the coke-ore comprehensive angle difference is -1.50°--0.10°, the coke-ore comprehensive angle difference being the ratio of the weighted average of the coke angle and the number of coke rings at each angle to the weighted average of the ore angle and the number of ore rings at each angle.

2. The vanadium titano-magnetite addition lignite injection blast furnace smelting method according to claim 1, characterized in that, The low-silicon high-alkalinity vanadium-titanium sinter has the following chemical composition by mass percentage: TFe 52.0~53.0%, FeO 8.30~9.50%, SiO2 5.5~6.5%, CaO 11.0~12.0%, MgO 2.50~3.00%, TiO2 1.00~1.60%, S 0.05~0.07%, Al2O3 2.00~2.50%, MnO 0.20~0.40%, and the balance is inevitable impurities; particle size 20~40 mm, drum index >78%. The low-silicon high-alkalinity vanadium-titanium small particle size sinter has a particle size of 5~8 mm, and the rest is the same as the low-silicon high-alkalinity vanadium-titanium sinter.

3. The vanadium titano-magnetite addition lignite injection blast furnace smelting method according to claim 1, characterized in that, The low-silicon high-titanium vanadium-titanium pellet has the following chemical composition by mass percentage: TFe 53.0~54.0%, FeO 2.00~2.60%, SiO2 4.60~5.30%, CaO 0.5~1.50%, MgO 1.0~2.0%, TiO2 2.5~3.5%, S 0.005~0.015%, Al2O3 2.0~3.0%, MnO 0.20~0.50%, and the balance is inevitable impurities; particle size 6 mm~19 mm, compressive strength >2000 N / individual.

4. The vanadium titano-magnetite addition lignite injection blast furnace smelting method according to claim 1, characterized in that, The chemical composition of the high-silicon acid-oxidizing pellet includes, in percentage by mass, TFe 58.5-61.0%, FeO 2.00-2.55%, SiO2 8.0-9.0%, CaO 1.0-1.20%, MgO 2.60-2.80%, TiO2 9.90-10.50%, S 0.005-0.015%, Al2O3 2.00-2.80%, MnO 0.05-0.15%, and the balance being inevitable impurities; the particle size is 6-19 mm, and the compressive strength is greater than 2000 N / individual.

5. The vanadium titano-magnetite charged blast furnace smelting method according to claim 1, characterized in that, The chemical composition of the high-ash coke used includes, in percentage by mass, moisture 1.0-5.0%, C 84.0-86.0%, ash 13.5-14.2%, S 0.50-0.75%, and volatile matter 0.50-1.20%; the balance being inevitable impurities; M40 is 88.0-90.0%, M10 is 4.0-5.0%; CRI is 23.0-26.0%, and CSR is 66.0-70.0%; the coke ash composition includes, in percentage by mass, K2O 0.30-0.65%, Na2O 0.30-0.75%, Fe2O3 6.0-8.0%, SiO2 53.0-55.0%, CaO 2.0-3.0%, MgO 0.20-0.50%, Al2O3 22.0-25.0%, TiO2 1.0-2.0%, and the balance being inevitable impurities; The small-size coke has a particle size of 10-20 mm, and the rest is the same as the high-ash coke.

6. The vanadium-titanium magnetite and lignite injection smelting method of blast furnace according to claim 1, characterized in that, The anthracite composition includes, in percentage by mass, moisture 1.0-2.0%, C 78.0-80.0%, V 7.5-9.5%, ash 11.0-12.5%, S 0.55-0.75%, and H 0.1-1.0%, and the balance being inevitable impurities; the anthracite ash composition includes, in percentage by mass, K2O 0.50-0.70%, Na2O 0.40-0.75%, Fe2O3 7.50-9.50%, SiO2 46.0-49.0%, CaO 5.0-6.5%, MgO 2.0-3.0%, Al2O3 23.0-25.0%, TiO2 1.0-2.0%, and the balance being inevitable impurities; and the anthracite particle size is 2-6 mm. The lean coal component includes, by mass percentage, water 1.0-5.0%, C 70.0-75.0%, V 11.0-15.0%, Ash 11.0-13.5%, S 0.60-0.75%, H 0.5-1.5%, and the balance being unavoidable impurities; the lean coal ash component includes, by mass percentage, K2O 0.40-0.70%, Na2O 0.30-0.55%, Fe2O3 7.00-9.00%, SiO2 48.0-53.0%, CaO 4.0-6.0%, MgO 5.0-8.0%, Al2O3 22.0-28.0%, TiO2 1.0-2.0%, and the balance being unavoidable impurities, with the lean coal having a particle size of 3-9 mm; The lignite component includes, by mass percentage, water 20.0-26.0%, C 35.0-40.0%, V 35.0-40.0%, Ash 5.0-10.0%, S 0.85-1.05%, H 3.0-6.0%, and the balance being unavoidable impurities and crystal water; the lignite ash component includes, by mass percentage, K2O 0.01-0.10%, Na2O 0.10-0.30%, Fe2O3 10.00-13.00%, SiO2 3.0-8.0%, CaO 40.0-50.0%, MgO 4.0-8.0%, Al2O3 23.0-26.0%, TiO2 0.1-1.0%, and the balance being unavoidable impurities, with the lignite having a particle size of 3-10 mm, a water content of <10.0%, and an ignition point of no less than 450℃; The three kinds of coal are fed into a pulverizing system, dried, and ground in a nitrogen atmosphere to obtain a mixed coal powder having a moisture content of 0.50-0.80%, a volatile content of 10-20%, an ash content of 9-12%, a fixed carbon content of >60%, and a fineness of a coal powder having a particle size of -200 mesh being no less than 60%.

7. The vanadium titano-magnetite charged blast furnace smelting method according to claim 1, characterized in that: In step B, the titanium load is defined, and when the titanium load needs to be increased, the proportion of low-silicon high-titanium vanadium-titanium pellets is increased, and the high-silicon acidic oxidizing vanadium-titanium pellets are reduced to 0, so as to maintain the titanium load within the upper limit of 60.0 kg / tFe of the defined range of 40.0-60.0 kg / tFe; if the titanium load exceeds the upper limit of 60.0 kg / tFe, the TiO2 content in the sinter is adjusted to maintain the titanium load and the slag basicity within the defined range; if the titanium load is 40 kg / tFe or more, the lignite ratio is increased according to the following proportions: when the titanium load is >40 kg / tFe, the coal injection ratio is no less than 140 kg / t; when the titanium load is >50 kg / tFe, the coal injection ratio is no less than 145 kg / t. When the selected coke metallurgical properties are checked, the following conditions need to be met: M40 is 87.0-90.0%, M10 is 4.0-5.0%, CRI is 22.0-26.0%, and CSR is 66.0-70.0%; if the conditions are met, the check is passed, and smelting is performed.

8. The vanadium titano-magnetite charged blast furnace smelting method according to claim 1, characterized in that: In the step D, when the titanium load is greater than 50 kg / tFe, the theoretical combustion temperature is not more than 2450 DEG C, the reduction rate of [Si] in pig iron is less than 3.0%, the reduction rate of [Ti] is less than 8.0%, and the permeability resistance coefficient is not more than 9.0; if the conditions are not met, the reasons are inquired, and the lignite ratio, coke load, air temperature, oxygen enrichment rate and coal injection ratio are adjusted; the theoretical combustion temperature (t 理 ) involved in the step D is calculated by the following formula: t 理 =1563+t 风 ×0.794+fO2×100×40.3+k 混煤 ×m 混煤 -H2O 风 ×6 Wherein: t 风 Blast furnace hot blast temperature, °C fO2 is the oxygen enrichment rate of blast furnace blast, %; k 混煤 Theoretical combustion temperature reduction effect of 1 kg of blast furnace injection mixed coal powder is decomposed in units of 1 ton of iron, negative value, ℃ / (kg / tFe); m 混煤 Mixed coal injection ratio for blast furnace, kg / t Fe; H2O 风 1 m 3 Water content in blast furnace blast, g / m 3 .

9. The vanadium titano-magnetite charged blast furnace smelting method according to claim 1, characterized in that: In the step E, if the following conditions are not met: the coal injection ratio is increased, the replacement ratio is not less than 0.98, and the coal powder injection cost reduction value is greater than 2.0 yuan / tFe, then the reasons are inquired, and the lignite ratio, coke load, oxygen enrichment rate, coal injection ratio and slag basicity are adjusted until the coal injection ratio is increased, the replacement ratio is not less than 0.98, and the coal powder injection cost reduction value is greater than 2.0 yuan / tFe, and the smelting is continued.

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