Smelting method for reducing combustion temperature in tuyere raceway zone of oxygen-enriched blast furnace

Abstract

The invention discloses a smelting method for reducing the combustion temperature of a tuyere whirlpool zone in an oxygen-enriched blast furnace, and the method comprises the following steps: preparing a mixed powder for blast furnace injection; taking 88-99 parts by weight of raw coal for injection and 1-12 parts by weight of an additive, grinding the mixed powder for injection after fully mixing; the raw coal for injection is prepared according to 40-50wt% of bituminous coal and 50-60wt% of anthracite; the additive is prepared according to 70-90wt% of blast furnace slag and 10-30wt% of magnesite; the iron-containing raw materials fed into the furnace are loaded into a furnace top material tank ... The iron raw materials include 70-75 parts of sintered ore, 22-29 parts of pelletized ore and 1-3 parts of scrap steel crushing material; the iron-containing raw materials are smelted in a manner of distributing the material on the furnace top from the outer ring to the inner ring and spraying mixed powder through the tuyere; wherein, the oxygen enrichment rate is 14-16%, the standard wind speed is 300-350m / s, the theoretical combustion temperature before the tuyere is 2300-2350℃, the pressure difference in the furnace is 0.160-0.180MPa, the wind temperature is 1200-1300℃, and the coal ratio is 180-250kg / t·Fe.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgy, and in particular relates to a method for reducing the combustion temperature of a tuyere raceway zone in an oxygen-enriched blast furnace. Background Art

[0002] Due to the increasingly stringent environmental protection requirements of the country and the restrictions of the metallurgical industry, steel companies will not be able to add new process equipment at present. However, at the same time, with the rapid development of my country's economy, the demand for steel products for different purposes is also increasing. In order to meet the rapidly growing needs of different industries for steel products, steel companies need to use existing equipment conditions and fully tap their own capabilities to cope with the growing market demand. As for the ironmaking process, the increase in production capacity, under the condition that new blast furnaces cannot be built, means that the production capacity itself must be increased, that is, the blast furnace smelting intensity must be increased accordingly to meet the needs of expanding production capacity.

[0003] At present, the most common way to strengthen smelting in blast furnaces is oxygen-enriched blast, that is, adding industrial oxygen to the hot air of the blast furnace to increase the oxygen enrichment rate of the blast, strengthen the combustion degree of the fuel in the tuyere vortex zone, improve the smelting intensity, and increase the output of the blast furnace. However, too high an oxygen enrichment rate will cause the tuyere combustion temperature to exceed the limit. The thermal state of the furnace has an important impact on the smooth operation of the blast furnace and the quality of molten iron. In the blast furnace production practice, the combustion temperature of the tuyere vortex zone is usually used as an important reference indicator to measure the thermal state of the furnace. A large number of production practices have shown that in order to maintain the normal working state of the blast furnace, the combustion temperature of the tuyere vortex zone should be stabilized within a reasonable range.

[0004] The combustion temperature in the vortex zone of the tuyere is too low, the fuel sprayed from the tuyere is not fully burned, and the charge is insufficiently heated, resulting in insufficient reduction of the iron ore and low slag temperature. The temperature is too high, SiO2 is gasified in large quantities, and the volume of coal gas expands rapidly, which increases the resistance to the descent of the charge and affects the smooth operation of the blast furnace. At the same time, the strong heat radiation caused by local high temperature accelerates the erosion of the refractory materials of the furnace hearth, causing the blast furnace to have a safety hazard of burning through the furnace hearth.

[0005] In order to match the increase in oxygen enrichment rate, high coal injection ratio operation is implemented in blast furnace production. Increasing the coal ratio can not only reduce the coke ratio to obtain greater economic benefits, but also reduce the combustion temperature in the tuyere whirlpool zone to keep it within a reasonable range. In order to maintain a high coal powder combustion rate and reduce the cost of coal injection, high-volatile bituminous coal is added to the blast furnace pulverized coal. Due to the influence of coal-forming geological conditions, age and other factors, bituminous coal contains a high amount of acidic substances in its ash, and the presence of too much acidic substances will lead to low ash melting performance. After the coal powder is sprayed into the blast furnace through the coal gun, it will burn quickly under the action of high wind temperature, and the bituminous coal itself has a high volatile content, which will cause it to slag and coke at the tuyere and other places when it encounters cooling, which will affect the service life of the tuyere and the uniformity of the blast furnace air intake, and will have an adverse effect on blast furnace production. At the same time, blast furnace coal injection directly affects the lower part of the blast furnace, especially the whirlpool and the coke bed nearby. The continuous increase in the amount of pulverized coal injection will result in the pulverized coal injected into the cyclone area not being fully burned, forming unburned pulverized coal, and too much unburned pulverized coal will affect the normal production of the blast furnace, making the blast furnace charge column permeability worse, the gas distribution in the furnace abnormal, and the blast furnace condition unsmooth. In fact, this kind of complementarity is difficult to achieve balance in industrial production, especially as the blast furnace continues to strengthen smelting, when the oxygen enrichment rate is above 10%, continuing to increase the amount of coal injection will affect the pulverized coal combustion rate and reduce the economic efficiency of blast furnace coal injection.

[0006] Therefore, when the amount of coal injection that the oxygen-enriched blast furnace can accept is not enough to maintain a suitable combustion temperature in the tuyere raceway zone, how to further reduce the combustion temperature in the tuyere raceway zone of the oxygen-enriched blast furnace is the main technical problem faced by ironmaking workers.

[0007] Some scholars have proposed adding CO2 gas to the hot air of the blast furnace, using the heat-absorbing characteristics of the reaction between CO2 gas and the coal powder and carbon elements in the tuyere cyclotron zone, and coke to solve the problem of excessive combustion temperature in the tuyere cyclotron zone due to excessive oxygen concentration in the hot air. However, the blast furnace is a high-temperature and high-pressure multiphase system. In the actual production process, the various operating parameters in the blast furnace, such as coke composition, coal powder composition, pig iron composition, blast volume, hot air temperature, and blast humidity, fluctuate greatly with the smelting process and cannot be detected in real time. The static tuyere cyclotron zone theoretical combustion temperature calculation model cannot derive the reasonable ratio of oxygen enrichment rate and CO2 at the optimal tuyere combustion temperature, which seriously affects the coordination of oxygen-rich blast and CO2-rich blast operations in the blast furnace blast. At the same time, the addition of CO2 gas to the hot air obviously increases carbon emissions.

[0008] From the perspective of coal powder injection, some enterprises try their best to inject some coal powder with high ash fusion performance such as anthracite, so as to improve the ash fusion performance of the mixed coal powder, avoid the occurrence of production-affecting phenomena such as slagging at the tuyere, and increase the coal injection ratio. However, this method also has the following defects, that is, the storage volume of resources such as anthracite is small, the price is high, and the grindability is low, the pulverization amount will be subject to certain restrictions, which will lead to certain restrictions on the coal injection ratio, and it is also not conducive to reducing the production cost of ironmaking, and will be subject to certain constraints in production.

[0009] Some enterprises improve the ash composition of mixed coal powder by adding some flux-like substances to the mixed coal powder, thereby improving the ash melting performance, avoiding production problems such as slagging and coking, and then increasing the coal ratio and reducing the combustion temperature of the vortex zone of the oxygen-enriched blast furnace tuyere. Such fluxes have achieved certain effects by adding high-melting-point oxides such as aluminum oxide and calcium oxide, but in terms of the existing technical implementation process, there are still certain problems, that is, the simple use of such fluxes will increase the cost of coal powder injection to a certain extent due to the high cost of the flux itself, which is not conducive to the economic smelting of blast furnaces. Summary of the invention

[0010] The present invention aims to provide a smelting method for reducing the combustion temperature of the tuyere whirlpool zone of an oxygen-enriched blast furnace, by adding blast furnace slag and magnesite ore to the injected mixed powder, so that the combustion temperature of the tuyere whirlpool zone of the oxygen-enriched blast furnace is within a reasonable range, thereby improving the blast furnace's ability to accept oxygen enrichment and the blast furnace output; the second purpose is to improve the combustion performance of coal powder when a large proportion of high-volatile bituminous coal is used for injection by adding blast furnace slag and magnesite ore, and reduce the amount of unburned coal powder generated after increasing the coal injection amount; the third purpose is to improve the acid-base ratio of blast furnace coal powder ash by adding alkaline blast furnace slag, thereby improving the ash melting performance; by adding magnesite ore, the mass percentage of MgO is increased, and the fluidity of blast furnace slag is improved.

[0011] In order to achieve the above purpose, the technical solutions adopted are as follows:

[0012] A smelting method for reducing the combustion temperature of a tuyere raceway in an oxygen-enriched blast furnace comprises the following steps:

[0013] (1) preparing a mixed powder for blast furnace injection; taking 88-99 parts by weight of raw coal for injection and 1-12 parts by weight of an additive, mixing them thoroughly and grinding them to obtain a mixed powder for blast furnace injection; the raw coal for blast furnace injection is prepared according to 40-50 wt% of bituminous coal and 50-60 wt% of anthracite; the additive is prepared according to 70-90 wt% of blast furnace slag and 10-30 wt% of magnesite;

[0014] (2) The iron-containing raw materials entering the furnace are loaded into the furnace top material tank; the iron-containing raw materials entering the furnace include 70-75 parts of sintered ore, 22-29 parts of pelletized ore and 1-3 parts of scrap steel crushing material;

[0015] (3) The iron-containing raw materials are smelted by distributing materials on the furnace top in a matrix distribution from the outer ring to the inner ring and spraying mixed powder at the tuyere; wherein the oxygen enrichment rate is 14-16%, the standard wind speed is 300-350 m / s, the theoretical combustion temperature before the tuyere is 2300-2350°C, the pressure difference in the furnace is 0.160-0.180 MPa, the wind temperature is 1200-1300°C, and the coal ratio is 180-250 kg / t·Fe.

[0016] According to the above scheme, the proportion of particles with a size of less than 200 mesh in the sprayed mixed powder is greater than or equal to 75wt%.

[0017] According to the above scheme, the iron content of the sintered ore is 57.5-60.0% by mass, the iron content of the pelletized ore is 63.0-68.0% by mass, and the specific gravity of the scrap steel crushing material is 5.5-6.5 g / cm 3 .

[0018] According to the above scheme, the total water (M t ) 10~14%, ash content (A d )7~9%, volatile matter (V daf ) 30~37%, total sulfur (S t,d )0~0.5%, Hardgrove Grindability Index (HGI) 60~80, Heat Generation (Q net,ar )24~40MJ / kg, the total amount of potassium oxide and sodium oxide in coal ash (K2O+Na2O)0~1.8%, phosphorus (P d )0~0.3%.

[0019] According to the above scheme, the anthracite has a total water content (Mt) of 5-10%, an ash content (A d )7~11%, volatile matter (V daf )7~12%, total sulfur (S t,d )0~0.6%, Hardgrove Grindability Index (HGI) 65~80, Fixed Carbon (FC d )75~85%, the total amount of potassium oxide and sodium oxide in coal ash (K2O+Na2O)0~1.8%, phosphorus (P d )0~0.3%.

[0020] According to the above scheme, the chemical composition weight percentage of the additive is: SiO2 25-32%, CaO 35-40%, MgO15-25%, Al2O3 10-14%, FeO 0-0.50%, MnO 0-0.30%, TiO2 0-1.0%.

[0021] According to the above scheme, the scrap steel crushing material is distributed on the edge ring belt of the material surface during the bell-free distribution process on the furnace top.

[0022] According to the above scheme, the cloth matrix in step 3 is: or or Among them, C is large coke, O is sintered ore + pelletized ore + scrap steel crushing material + coke diced, the upper right number is the distribution angle, and the lower right number is the number of distribution rings corresponding to the upper right number.

[0023] According to the above scheme, anthracite is selected from one or two of Henan Yongcheng anthracite and Shanxi Jincheng anthracite, and bituminous coal is selected from one or two of Shanxi Yulin bituminous coal and Shaanxi Shenfu bituminous coal.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] After adding blast furnace slag and magnesite ore to the sprayed mixed powder, the invention utilizes the heat absorption characteristic of the additives at high temperature to make the combustion temperature of the tuyere whirlpool zone of the oxygen-enriched blast furnace within a reasonable range, thereby improving the ability of the blast furnace to accept oxygen enrichment and increasing the output of the blast furnace.

[0026] The present invention uses a large proportion of high-volatile bituminous coal for injection in the mixed powder, thereby reducing the cost of coal injection; at the same time, blast furnace slag and magnesite are added to improve the combustion performance of coal powder, greatly reduce the amount of unburned coal powder generated after increasing the amount of coal injection, and improve the combustion efficiency of coal powder. This is because the combustion process of coal powder is mainly controlled by the diffusion of oxygen. Adding a small amount of oxygen-containing blast furnace slag to the coal powder can increase the concentration of oxygen or oxidizing substances in the combustion zone, improve the oxygen supply conditions during the combustion of coal powder, promote the combustion of coal powder, and thus improve the combustion rate of coal powder.

[0027] The present invention adds blast furnace slag and magnesite ore to the mixed powder sprayed in the blast furnace. The addition of alkaline blast furnace slag can improve the acid-base ratio of blast furnace coal powder ash and improve the ash melting performance, thereby optimizing the blast furnace coal powder spraying process effect. At the same time, the addition of magnesite ore increases the mass percentage of MgO and improves the fluidity of the blast furnace slag. DETAILED DESCRIPTION

[0028] The following examples further illustrate the technical solution of the present invention, but are not intended to limit the scope of protection of the present invention.

[0029] A specific embodiment provides a smelting method for reducing the combustion temperature of the tuyere raceway zone in an oxygen-enriched blast furnace, comprising the following steps:

[0030] (1) preparing a mixed powder for blast furnace injection; taking 88-99 parts by weight of raw coal for injection and 1-12 parts by weight of an additive, mixing them thoroughly and grinding them to obtain a mixed powder for blast furnace injection; the raw coal for blast furnace injection is prepared according to 40-50 wt% of bituminous coal and 50-60 wt% of anthracite; the additive is prepared according to 70-90 wt% of blast furnace slag and 10-30 wt% of magnesite;

[0031] (2) The iron-containing raw materials entering the furnace are loaded into the furnace top material tank; the iron-containing raw materials entering the furnace include 70-75 parts of sintered ore, 22-29 parts of pelletized ore and 1-3 parts of scrap steel crushing material;

[0032] (3) The iron-containing raw materials are smelted by distributing materials on the furnace top in a matrix distribution from the outer ring to the inner ring and spraying mixed powder at the tuyere; wherein the oxygen enrichment rate is 14-16%, the standard wind speed is 300-350 m / s, the theoretical combustion temperature before the tuyere is 2300-2350°C, the pressure difference in the furnace is 0.160-0.180 MPa, the wind temperature is 1200-1300°C, and the coal ratio is 180-250 kg / t·Fe.

[0033] Specifically, the proportion of particles with a particle size of less than 200 mesh in the sprayed mixed powder is greater than or equal to 75wt%.

[0034] Specifically, the iron content of the sintered ore is 57.5-60.0% by weight, the iron content of the pelletized ore is 63.0-68.0% by weight, and the specific gravity of the scrap steel is 5.5-6.5 g / cm 3 (density).

[0035] Specifically, the total water (M t ) 10~14%, ash content (A d )7~9%, volatile matter (V daf ) 30~37%, total sulfur (S t,d )0~0.5%, Hardgrove Grindability Index (HGI) 60~80, Heat Generation (Q net,ar )24~40MJ / kg, the total amount of potassium oxide and sodium oxide in coal ash (K2O+Na2O)0~1.8%, phosphorus (P d ) 0~0.3%. In the embodiment, the bituminous coal is selected from one or two of Shanxi Yulin bituminous coal and Shaanxi Shenfu bituminous coal.

[0036] Specifically, the anthracite has a total water content (Mt) of 5-10%, an ash content (A d )7~11%, volatile matter (V daf )7~12%, total sulfur (S t,d )0~0.6%, Hardgrove Grindability Index (HGI) 65~80, Fixed Carbon (FC d)75~85%, the total amount of potassium oxide and sodium oxide in coal ash (K2O+Na2O)0~1.8%, phosphorus (P d ) 0~0.3%. In the embodiment, the anthracite is selected from one or two of Henan Yongcheng anthracite and Shanxi Jincheng anthracite.

[0037] Specifically, the chemical composition weight percentage of the additive is: SiO2 25-32%, CaO 35-40%, MgO 15-25%, Al2O3 10-14%, FeO 0-0.50%, MnO 0-0.30%, TiO2 0-1.0%.

[0038] Specifically, the scrap steel crushing material should be placed at the front end of the ore main belt and loaded into the furnace top material tank first, so that it can be distributed on the edge ring belt of the material surface during the bell-free distribution process on the furnace top.

[0039] Specifically, the distribution matrix used in the blast furnace is: or or Among them, C is large coke, O is sintered ore + pelletized ore + scrap steel crushing material + coke diced, the upper right number is the distribution angle, and the lower right number is the number of distribution rings corresponding to the upper right number.

[0040] Embodiment 1:

[0041] An iron smelting plant 3200m 3 For blast furnace, the raw coal for injection is Shanxi Jincheng anthracite + Shaanxi Shenfu bituminous coal. The technical indicators of raw coal injection are shown in Table 1.

[0042] Table 1 Technical indicators of raw coal injection in a blast furnace

[0043]

[0044] Preparation of raw coal for injection: 42wt% bituminous coal from Shenfu, Shaanxi, 58wt% anthracite from Jincheng, Shanxi. (The names in Table 1 do not correspond to the technical solution)

[0045] Preparation of additives: 79wt% of naturally cooled blast furnace slag and 21wt% of magnesite ore were crushed and mixed evenly. The additive composition is shown in Table 2.

[0046] Table 2 Composition of injection additives in a blast furnace

[0047]

[0048] 90 parts of raw coal for injection and 10 parts of additives are taken, fully mixed and then ground into powder to form a mixed powder with a mass percentage of 80% of the particle size below 200 meshes.

[0049] The iron-containing raw materials ready for the furnace are loaded into the furnace top material tank. When the blast furnace has no clock request for ore, the scrap steel crushing material hopper is opened first, and it is confirmed that the front end of the single batch of ore main belt is scrap steel crushing material. All the iron-containing raw materials entering the blast furnace include 70 parts of sintered ore, 27 parts of pelletized ore and 3 parts of scrap steel crushing material. Among them, the iron content of sintered ore is 59.0% by mass, the iron content of pelletized ore is 66.0% by mass, and the specific gravity of scrap steel crushing material is 5.8g / cm 3 .

[0050] The distribution matrix of the blast furnace top is from the outer ring to the inner ring. The mixed powder is sprayed through the tuyere for smelting. The control range of smelting parameters is as follows: oxygen enrichment rate 14%, standard wind speed 315m / s, theoretical combustion temperature before the tuyere 2320℃, pressure difference in the furnace 0.165MPa, wind temperature 1250℃, coal ratio 212kg / t·Fe.

[0051] During the smelting process, the material speed is uniform and the material is discharged smoothly, without slipping materials and pipes on the edge. The gas utilization efficiency of the blast furnace is 47.6%, the coke ratio is 310.7kg / t·Fe, the fuel ratio is 522.7kg / t·Fe, and the utilization coefficient is 2.95t / m 3 .d.

[0052] The results show that, under the conditions of oxygen enrichment rate of 14% and coal ratio of 212kg / t·Fe, the present invention reduces the temperature of the tuyere whirlpool zone of the oxygen-enriched blast furnace by injecting a mixed powder containing 10% additives and optimizing the blast furnace smelting technical parameters, avoids the problem of too high temperature in the tuyere whirlpool zone and rapid expansion of coal gas volume leading to difficulty in charging, and the blast furnace charging speed is uniform and the charging is smooth, without slipping materials and pipelines on the edge, and the utilization coefficient reaches 2.95t / m 3 .d. The oxygen-enriched blast furnace achieves efficient production and maintains stable furnace conditions.

[0053] Embodiment 2:

[0054] An iron smelting plant 3200m 3 For blast furnace, the raw coal for injection is Henan Yongcheng anthracite + Shanxi Yulin bituminous coal. The technical indicators of raw coal injection are shown in Table 3.

[0055] Table 3 Technical indicators of raw coal injection in a blast furnace

[0056]

[0057] Preparation of raw coal for PCI: 40wt% Shanxi Yulin bituminous coal and 60wt% Henan Yongcheng anthracite.

[0058] Preparation of additives: 70wt% of naturally cooled blast furnace slag and 30wt% of magnesite ore are crushed and mixed evenly. The additive composition is shown in Table 4.

[0059] Table 4 Composition of injection additives for a blast furnace

[0060]

[0061] 92 parts of raw coal for injection and 8 parts of additives are taken, fully mixed and then ground into powder to form a mixed powder with a mass percentage of 82% of the particle size below 200 meshes.

[0062] The iron-containing raw materials ready for the furnace are loaded into the furnace top material tank. When the blast furnace has no clock request for ore, the scrap steel crushing material hopper is opened first, and it is confirmed that the front end of the single batch of ore main belt is scrap steel crushing material. The total iron-containing raw materials entering the blast furnace include 72 parts of sintered ore, 26 parts of pelletized ore and 2 parts of scrap steel crushing material. Among them, the iron content of sintered ore is 58.5% by mass, the iron content of pelletized ore is 65.3% by mass, and the specific gravity of scrap steel crushing material is 6.0g / cm 3 .

[0063] The distribution matrix of the blast furnace top is from the outer ring to the inner ring. The mixed powder is sprayed through the tuyere for smelting. The control range of smelting parameters is as follows: oxygen enrichment rate 15%, standard wind speed 320m / s, theoretical combustion temperature before the tuyere 2310℃, pressure difference in the furnace 0.160MPa, wind temperature 1250℃, coal ratio 215kg / t·Fe.

[0064] During the smelting process, the material speed is uniform and the material is discharged smoothly, without slipping materials and pipes at the edge. The gas utilization efficiency of the blast furnace is 48.1%, the coke ratio is 301.3kg / t·Fe, the fuel ratio is 516.3kg / t·Fe, and the utilization coefficient is 3.01t / m 3 .d.

[0065] The results show that, under the conditions of oxygen enrichment rate of 15% and coal ratio of 215kg / t·Fe, the present invention reduces the temperature of the tuyere whirlpool zone of the oxygen-enriched blast furnace by injecting a mixed powder containing 8% additives and optimizing the blast furnace smelting technical parameters, avoids the problem of too high temperature in the tuyere whirlpool zone and rapid expansion of coal gas volume leading to difficulty in charging, and the blast furnace charging speed is uniform and the charging is smooth, without slipping materials and pipelines on the edge, and the utilization coefficient reaches 3.01t / m 3 .d. The oxygen-enriched blast furnace achieves efficient production and maintains stable furnace conditions.

Claims

1. A smelting method for reducing the combustion temperature of the tuyere raceway in an oxygen-enriched blast furnace, characterized in that The following steps are involved: (1) Preparing a mixed powder for blast furnace injection; taking 88-99 parts by weight of raw coal for injection and 1-12 parts by weight of an additive, mixing them thoroughly and then grinding them to obtain a mixed powder for blast furnace injection; the raw coal for injection is prepared according to 40-50wt% of bituminous coal and 50-60wt% of anthracite; the additive is prepared according to 70-90wt% of blast furnace slag and 10-30wt% of magnesite; the chemical composition weight percentage of the additive is: SiO2 25-32%, CaO 35-40%, MgO 15-25%, Al2O3 10-14%, FeO 0-0.50%, MnO 0-0.30%, TiO2 0-1.0%; (2) The iron-containing raw materials entering the furnace are loaded into the furnace top material tank; the iron-containing raw materials entering the furnace include 70-75 parts of sintered ore, 22-29 parts of pelletized ore and 1-3 parts of scrap steel crushing material; (3) The iron-containing raw materials are smelted by distributing materials on the furnace top in a matrix from the outer ring to the inner ring and spraying mixed powder at the tuyere; the oxygen enrichment rate is 14-16%, the standard wind speed is 300-350 m / s, the theoretical combustion temperature before the tuyere is 2300-2350°C, the pressure difference in the furnace is 0.160-0.180 MPa, the wind temperature is 1200-1300°C, and the coal ratio is 180-250 kg / t·Fe.

2. The smelting method for reducing the combustion temperature of the tuyere raceway in an oxygen-enriched blast furnace according to claim 1, characterized in that The sprayed mixed powder has a particle size of less than 200 meshes accounting for greater than or equal to 75wt%.

3. The smelting method for reducing the combustion temperature of the tuyere raceway in an oxygen-enriched blast furnace as claimed in claim 1, characterized in that The iron content of the sintered ore is 57.5-60.0% by mass, the iron content of the pelletized ore is 63.0-68.0% by mass, and the specific gravity of the scrap steel crushing material is 5.5-6.5 g / cm 3 .

4. The smelting method for reducing the combustion temperature of the tuyere raceway in an oxygen-enriched blast furnace as claimed in claim 1, characterized in that The total water content of the bituminous coal M t 10~14%, ash content A d 7~9%, Volatile matter V daf 30~37%, total sulfur S t,d 0~0.5%, Hastelloy Grindability Index HGI 60~80, Heat Generation Q net,ar 24~40MJ / kg, the total amount of potassium oxide and sodium oxide in coal ash is 0~1.8%, phosphorus content is P d 0~0.3%.

5. The smelting method for reducing the combustion temperature of the tuyere raceway in an oxygen-enriched blast furnace as claimed in claim 1, characterized in that The anthracite has a total water content of 5-10%, an ash content of 20% and a d 7~11%, Volatile matter V daf 7~12%, total sulfur S t,d 0~0.6%, Hastelloy Grindability Index HGI 65~80, Fixed Carbon FC d 75~85%, the total amount of potassium oxide and sodium oxide in coal ash is 0~1.8%, phosphorus content is d 0~0.3%.

6. The smelting method for reducing the combustion temperature of the tuyere raceway in an oxygen-enriched blast furnace as claimed in claim 1, characterized in that The scrap steel crushing material is distributed on the edge ring belt of the material surface during the bell-free distribution process on the furnace top.

7. The smelting method for reducing the combustion temperature of the tuyere raceway in an oxygen-enriched blast furnace as claimed in claim 1, characterized in that The cloth matrix in step 3 is: or or , where C is large coke, O is sintered ore + pelletized ore + scrap steel crushing + coke diced, the upper right number is the distribution angle, and the lower right number is the number of distribution rings corresponding to the upper right number.

8. The smelting method for reducing the combustion temperature of the tuyere raceway in an oxygen-enriched blast furnace as claimed in claim 1, characterized in that Anthracite can be selected from one or two of Henan Yongcheng anthracite and Shanxi Jincheng anthracite, and bituminous coal can be selected from one or two of Shanxi Yulin bituminous coal and Shaanxi Shenfu bituminous coal.

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