A method for charging materials separately, searching for the domain for charging, and removing superposition in the softening and melting zone

Abstract

The present invention relates to a method for charging and distributing furnace burden in a search domain and removing superposition in the softening-melting zone. The method comprises the following steps: Step 1: Using a bell-less top charging method, according to the position of the burden surface at the top of the blast furnace, the furnace burden is charged into the furnace in a cyclic manner by using the charging modes of coke, acidic burden, and basic burden respectively; Step 2: The coke is spread flat on the original burden surface at the top of the blast furnace through a rotary chute, the acidic burden is distributed on the coke layer in the area near the edge of the blast furnace through the rotary chute, and the basic burden is distributed on the coke layer in the area near the center of the blast furnace through the rotary chute. Thus, the charging and distributing of the furnace burden in the search domain are completed. This solution can significantly reduce the thickness of the softening-melting zone under the condition of the original mixed furnace burden by concentrating the acidic burden in the edge area of the ore platform. The permeability of the blast furnace becomes better, the differential pressure of the blast furnace decreases, the distribution of the coal gas flow is improved, the utilization rate of the coal gas is increased, the fuel ratio of the blast furnace is reduced, the output is increased, the carbon emission of the blast furnace is reduced at the same time, and the environment is optimized.

Description

Technical Field

[0001] The present invention relates to a method, specifically to a method for charging burden in different zones and softening and melting zone superimposition removal, belonging to the technical field of blast furnace ironmaking. Background Art

[0002] Blast furnace burden distribution is one of the important means to achieve a reasonable distribution of the gas flow in the furnace, ensure the smooth operation of the blast furnace and the best utilization of energy. At present, the burden distribution of blast furnaces is generally the bell-less type of mixed burden distribution. By taking advantage of the flexible burden distribution of the bell-less blast furnace top charging equipment, the accuracy of burden distribution is achieved through optimizing the blast furnace burden distribution operation, the optimization of the blast furnace gas flow distribution is realized, and then the gas utilization rate in the furnace is improved, the fuel ratio is reduced, and the economic and technical indexes of blast furnace smelting are improved. The softening and melting zone of the blast furnace is one of the key factors affecting the blast furnace gas flow distribution. Generally, it is desired that the blast furnace has an inverted V-shaped softening and melting zone. The inverted V-shaped softening and melting zone can promote the development of the central gas flow, which is beneficial to activating and loosening the central burden column, thereby reducing the blast furnace differential pressure. The inverted V-shaped softening and melting zone can also improve the secondary distribution of the gas flow, increase the contact area and time between the gas flow and the ore in the burden zone, promote the development of indirect reduction, and is beneficial to enhancing the blast furnace gas utilization rate and reducing the fuel ratio. Due to the development of the central gas flow, the peripheral gas flow is relatively weakened, which can reduce the thermal load and scouring effect on the furnace lining, reduce heat loss and protect the furnace lining.

[0003] The position, shape and thickness of the blast furnace softening and melting zone are affected by the metallurgical properties of the burden and the blast furnace burden distribution system. Generally, basic burden (mainly high-alkali sinter) has a relatively high starting softening and melting and dripping temperature in the blast furnace, and a relatively small softening and dripping interval. When used as blast furnace burden, the position of the softening and melting zone is relatively low and the thickness of the softening and melting zone is relatively thin, which is beneficial to improving the permeability of the blast furnace. Acid burden (mainly pellet and lump ore) has a relatively low starting softening and melting and dripping temperature in the blast furnace, and a relatively large softening and dripping interval. When used as blast furnace burden, the position of the softening and melting zone is relatively high and the thickness of the softening and melting zone is relatively thick, which is not beneficial to improving the permeability of the blast furnace. At present, the burden structure of domestic blast furnaces is mainly high-alkali sinter, supplemented with a small amount of pellet and lump ore. However, due to the characteristics of low energy consumption and less pollutant emissions in pellet production, with the in-depth development of blast furnace energy conservation and emission reduction work, increasing the proportion of pellet use has become the key work for enterprises to achieve ultra-low emissions. How to achieve the stable and smooth operation of blast furnace smelting under the condition of high proportion of pellet smelting has become the key work for technical personnel of many iron and steel enterprises in the next period of time. In addition, lump ore is also a raw material directly charged into the furnace without sintering. Using a large proportion of lump ore in the blast furnace conforms to the development trend of ultra-low emissions and the technical direction of significant cost reduction. The technology of charging acid burden in different zones provides a powerful technical means for using a large proportion of lump ore (20-25%) and exploring the limit lump ore ratio (25-30%).

[0004] This application takes advantage of the large differences in the softening characteristics of pellet ore, lump ore, and high-alkali sinter, innovates the burden distribution method in the blast furnace, concentrates the acidic burden in the edge area of the ore platform, significantly reduces the height and thickness of the inverted V-shaped softening zone under the original mixed burden conditions, reduces the blast furnace differential pressure, improves the distribution of the coal gas flow, increases the utilization rate of the coal gas, reduces the blast furnace fuel ratio, and is of great significance for achieving the energy consumption benchmark value of blast furnace smelting and reducing CO2 emissions. Summary of the Invention

[0005] The present invention precisely aims at the problems existing in the prior art and provides a method for separately charging and region-seeking burden distribution and softening zone superposition removal. This technical solution significantly reduces the thickness of the softening zone under the original mixed burden conditions, improves the permeability of the blast furnace, reduces the blast furnace differential pressure, improves the distribution of the coal gas flow, enhances the utilization rate of the coal gas, and reduces the blast furnace fuel ratio.

[0006] To achieve the above object, the technical solution of the present invention is as follows. A method for separately charging and region-seeking burden distribution and softening zone superposition removal, characterized in that the method comprises the following steps:

[0007] Step 1: Adopt bell-less top burden distribution, and according to the position of the burden surface at the top of the blast furnace, use the charging modes of coke, acidic burden, and alkaline burden respectively for cyclic charging of the burden into the furnace;

[0008] Step 2: The coke is spread flat on the original burden surface at the top of the blast furnace through the rotary chute, the acidic burden is distributed on the coke layer in the area near the edge of the blast furnace through the rotary chute, and the alkaline burden is distributed on the coke layer in the area near the center of the blast furnace through the rotary chute. Thus, the separately charging and region-seeking burden distribution is completed.

[0009] As an improvement of the present invention, in Step 1, the average particle size of the coke is greater than 35 mm, M40 is greater than 80%, M10 is less than 8%, CSR is greater than 60%, and CRI is less than 26%. M40 and M10 are indexes characterizing the cold strength of coke. M40 represents the percentage of coke greater than 40 mm after the drum test of coke cold strength, and M10 represents the percentage of coke less than 10 mm after the drum test of coke cold strength. CSR and CRI are indexes characterizing the hot strength of coke. CSR represents the drum strength after the reaction of coke, indicating the proportion of coke greater than 10 mm after the drum test; CRI represents the reactivity of coke, indicating the proportion of the mass loss part after the reaction of coke.

[0010] As an improvement of the present invention, in Step 1, the acidic burden is pellet ore, lump ore, and a mixture of the two, with an alkalinity less than 0.8, an iron grade greater than 60%, an average particle size greater than 12 mm, the starting softening temperature of the acidic burden being 870 - 1050 °C (setting 900 °C as its characteristic temperature value), and the melting temperature being 1150 - 1250 °C.

[0011] As an improvement of the present invention, in step 1, the basic burden is high basicity sinter, with basicity greater than 1.7, iron grade greater than 52%, average particle size greater than 15 mm, starting softening temperature of 1100 - 1200 °C (setting 1150 °C as its characteristic temperature value), and melting temperature of 1300 - 1380 °C.

[0012] As an improvement of the present invention, in step 2, the acidic burden is lifted to the bunker through the feeding device, and by adjusting the angle of the rotary chute to 35 - 45°, the acidic burden is distributed in a multi-ring feeding manner to the edge area set above the coke layer. The acidic burden in this area starts to soften until it descends to the position where it intersects with the 900 °C isotherm of the basic burden column.

[0013] As an improvement of the present invention, in step 2, the basic burden is lifted to the bunker through the feeding device, and by adjusting the angle of the rotary chute to 30 - 45°, the basic burden is distributed in a multi-ring feeding manner onto the coke layer and the acidic burden layer. For each ring, the amount of burden fed is controlled by setting the number of feeding circles. On the ring corresponding to the acidic burden, the number of feeding circles of the basic burden can be reduced to 0 as needed. After the acidic burden and the basic burden are fed, an ore layer is formed, and the ore layer becomes an ideal burden column structure with a frustum-shaped burden column formed by a single sinter and an annular interlayer formed by the acidic burden. For the softening interval formed by the single sinter burden column, its starting softening temperature is 1150 °C (characteristic temperature value), while for the softening interval of the mixed burden (the burden formed by the uniform mixing of the acidic burden and the basic burden), its starting softening temperature is 900 °C (characteristic temperature value).

[0014] As an improvement of the present invention, in step 2, the basic burden has a high softening temperature and melting temperature, and the acidic burden has a low softening temperature and melting temperature. When the two types of burdens are mixed and fed, the softening intervals overlap, that is, the softening temperature of the mixture is the lower limit of the softening temperatures of the two types of burdens, and the melting temperature takes the upper limit of the melting temperatures of the two types of burdens, resulting in an increase in the softening temperature interval and thickness of the softening zone of the mixed burden. When the basic burden and the acidic burden are separately fed and distributed in different areas, most of the starting softening temperature line of the blast furnace burden column is formed in the basic burden area. The acidic burden starts to soften only when it descends to the root position of the softening zone where it intersects with the 900 °C softening characteristic temperature. The softening temperatures of the two types of burdens do not overlap in most parts of the softening zone, and only a very small part at the root of the softening zone has an overlap. The thickness of the blast furnace softening zone decreases, and the reduced temperature interval is: characteristic temperature 1150 °C - characteristic temperature 900 °C = 250 °C.

[0015] Compared with the prior art, the present invention has the following advantages. Based on the difference in the softening properties of acidic and basic furnace charges in a blast furnace, the present invention proposes a method different from the traditional burden distribution mode, in which sinter, pellet and lump ore are approximately evenly distributed on the burden surface of the blast furnace, resulting in a low softening temperature, a high melting temperature and a wide softening temperature range of the mixed charge, which causes the softening zone in the blast furnace to become thicker and is not conducive to the improvement of the blast furnace technical and economic indicators. By concentrating the acidic furnace charge in the edge area of the ore platform, the thickness of the softening zone under the original mixed furnace charge conditions is greatly reduced, the blast furnace permeability is improved, the blast furnace differential pressure is reduced, the coal gas flow distribution is improved, the gas utilization rate is increased, the blast furnace fuel ratio is reduced, the output is increased, and at the same time, the blast furnace carbon emission is reduced and the environment is optimized. This method has a simple operation process and strong practicability, and is of great significance to the selection and optimization of burden distribution in the blast furnace smelting site. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the burden distribution and seeking domain method for furnace charge. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] In order to deepen the understanding of the present invention, the following detailed description is made with reference to the accompanying drawings for this embodiment.

[0018] Example 1: Refer to Figure 1 , a method for burden distribution and seeking domain of furnace charge and softening interval superposition, the method comprising the following steps:

[0019] Step 1: Adopt the bell-less top burden distribution. According to the position of the top burden surface in the blast furnace, the furnace charge is charged into the furnace in a cyclic manner by using the separate charging modes of coke, acidic furnace charge and basic furnace charge respectively;

[0020] Step 2: The coke is spread evenly on the original burden surface of the blast furnace top through the rotary chute, the acidic furnace charge is distributed on the coke layer in the area close to the blast furnace edge through the rotary chute, and the basic furnace charge is distributed on the coke layer in the area close to the blast furnace center through the rotary chute. Thus, the burden distribution and seeking domain of furnace charge are completed.

[0021] In step 1, the average particle size of the coke is greater than 35 mm, M40 is greater than 80%, M10 is less than 8%, CSR is greater than 60%, and CRI is less than 26%.

[0022] In step 1, the acidic furnace charge is pellet, lump ore and their mixture, the basicity is less than 0.8, the iron grade is greater than 60%, the average particle size is greater than 12 mm, the initial softening temperature of the acidic furnace charge is 870 - 1050 °C (set 900 °C as its characteristic temperature value), and the melting temperature is 1150 - 1250 °C.

[0023] In Step 1, the basic burden is high-alkali sinter with an alkalinity greater than 1.7, an iron grade greater than 52%, an average particle size greater than 15 mm, an initial softening temperature of 1100 - 1200 °C (with 1150 °C set as its characteristic temperature value), and a melting temperature of 1300 - 1380 °C.

[0024] In Step 2, the acidic burden is lifted to the bunker through the feeding device. By adjusting the angle of the rotary chute to 35 - 45°, the acidic burden is distributed in a multi-ring feeding manner to the set edge area above the coke layer. The acidic burden in this area starts to soften until it descends to the position where it intersects with the 900 °C isotherm of the basic burden column.

[0025] In Step 2, the basic burden is lifted to the bunker through the feeding device. By adjusting the angle of the rotary chute to 30 - 45°, the basic burden is distributed in a multi-ring feeding manner onto the coke layer and the acidic burden layer. For each ring, the feeding amount is controlled by setting the number of feeding circles. On the ring corresponding to the acidic burden, the number of feeding circles of the basic burden can be reduced to 0 as needed. After the acidic and basic burdens are fed, an ore layer is formed, and the ore layer becomes an ideal burden column structure with a frustum-shaped column formed by a single sinter and an annular interlayer formed by the acidic burden. For the softening interval of the single sinter burden column, its initial softening temperature is 1150 °C (characteristic temperature value), while for the softening interval of the mixed burden (the burden formed by the uniform mixing of the acidic and basic burdens), its initial softening temperature is 900 °C (characteristic temperature value).

[0026] In Step 2, the basic burden has a high softening temperature and melting temperature, while the acidic burden has a low softening temperature and melting temperature. When the two types of burdens are mixed and fed, the softening intervals overlap, that is, the softening temperature of the mixture is the lower limit of the softening temperatures of the two types of burdens, and the melting temperature takes the upper limit of the melting temperatures of the two types of burdens, resulting in an increase in the softening temperature interval and thickness of the softening zone of the mixed burden. When the basic and acidic burdens are separately fed and distributed in different areas, most of the initial softening temperature line of the blast furnace burden column is formed in the basic burden area. The acidic burden starts to soften only when it descends to the root position of the softening zone where it intersects with the 900 °C softening characteristic temperature. The softening temperatures of the two types of burdens do not overlap in most of the softening zone, and only a very small part at the root of the softening zone has an overlap. The thickness of the blast furnace softening zone decreases, and the reduced temperature interval is: characteristic temperature 1150 °C - characteristic temperature 900 °C = 250 °C.

[0027] Application Example 1

[0028] For a 1580 m 3 blast furnace in a steel plant, the blast furnace burden structure is smelted with high-alkali sinter and acidic pellet. The method of separately feeding and distributing different burdens in different areas and reducing the thickness by overlapping the softening intervals is completed according to the following steps:

[0029] The bell-less top burden distribution is adopted. According to the position of the burden surface at the top of the blast furnace, the charging mode of coke, acidic burden, and basic burden is respectively used for the cyclic charging of the burden into the furnace.

[0030] The coke is spread evenly on the original burden surface at the top of the blast furnace through the revolving chute. The acidic burden is distributed on the area near the edge of the blast furnace on the coke layer through the revolving chute. The basic burden is distributed on the area near the center of the blast furnace on the coke layer through the revolving chute. Thus, the burden distribution in the furnace is completed. The physical properties of the coke, acidic burden, and basic burden used in the blast furnace smelting are shown in Table 1.

[0031] Table 1: Physical properties of coke, basic burden, and acidic burden used in blast furnace smelting

[0032] The burden structure used in blast furnace smelting is 60% high-alkali sinter + 40% acidic pellet. During the production process, the charging time is determined according to the position of the burden surface at the top of the blast furnace. The weight of coke added each time for blast furnace burden distribution is 15t. The coke is lifted to the bunker through the charging device, and then the angle of the revolving chute is adjusted between 15° and 40°, and multi-ring burden distribution is carried out in 5 gears. The coke is arranged in a flat form from the edge of the furnace wall to the center on the original burden surface at the top of the blast furnace. After the coke is distributed, 27t of acidic pellets are lifted to the bunker through the charging device, and then the angle of the revolving chute is adjusted between 32 - 40°, and multi-ring burden distribution is carried out in 2 gears. The acidic pellets are distributed to the set area near the edge of the blast furnace on the coke layer. After the acidic burden is distributed, 41 tons of high-alkali sinter are lifted to the bunker through the charging device, and then the angle of the revolving chute is adjusted between 18 - 30°, and multi-ring burden distribution is carried out in 3 gears. The high-alkali sinter is distributed to the area near the center of the blast furnace on the coke layer.

[0033] The initial softening temperature of the high-alkali sinter is 1200°C, and the melting temperature is 1450°C. The initial softening temperature of the acidic pellet is 950°C, and the melting temperature is 1300°C. When using the traditional all-region burden distribution of sinter and pellet, the initial softening temperature of the mixed ore is 950°C, the melting temperature is 1450°C, and the softening and dripping temperature range is 500°C. When using the burden distribution by separate charging and seeking regions in the blast furnace, the high-alkali sinter is in the central region of the blast furnace, and the softening and dripping temperature range is 250°C. The acidic pellet is in the edge region, and the softening and dripping temperature range is 350°C. The softening and dripping temperature ranges in different regions have all decreased significantly, resulting in a significant thinning of the softening-melting zone in the blast furnace, better permeability of the blast furnace, lower blast furnace differential pressure, improved distribution of the coal gas flow, increased utilization rate of the gas, reduced blast furnace fuel ratio, increased output, and at the same time reduced the carbon emissions of the blast furnace. The application effect of Example 1 is shown in Table 2.

[0034] Table 2: Application effect of blast furnace

[0035] At 1580m3 After the implementation in the blast furnace, by separately charging and distributing the high-alkali sinter and acidic pellet in different areas, the thickness of the softening-melting zone was effectively reduced, the permeability of the blast furnace was improved, achieving a good operating effect of reducing the blast furnace differential pressure by 8 kPa, increasing the gas utilization rate by 0.6%, reducing the fuel ratio by 15 kg / tHM, increasing the daily output by 132 t, and saving the molten iron cost by 57 yuan, realizing low fuel ratio, high efficiency, and low-carbon emission smelting in the blast furnace.

[0036] Application Example 2

[0037] A 2500 m 3 blast furnace in a steel plant. The burden structure of the blast furnace is smelting with high-alkali sinter combined with acidic pellets. The method of separately charging and distributing different burden materials in different areas and the method of reducing the thickness by superimposing in the softening-melting zone are completed according to the following steps:

[0038] The bell-less top charging is adopted. According to the position of the burden surface at the top of the blast furnace, the charging modes of coke, acidic burden, and basic burden are respectively used for the burden to be cycled into the furnace for charging;

[0039] The coke is spread flat on the original burden surface at the top of the blast furnace through the rotary chute. The acidic burden is distributed on the coke layer in the area near the edge of the blast furnace through the rotary chute. The basic burden is distributed on the coke layer in the area near the center of the blast furnace through the rotary chute. Thus, the burden charging in the furnace is completed. The physical properties of the coke, basic burden, and acidic burden used in the blast furnace smelting are shown in Table 3.

[0040] Table 3: Physical properties of coke, basic burden, and acidic burden used in blast furnace smelting

[0041] The burden structure used in the blast furnace smelting is 70% high-alkali sinter + 30% acidic pellets. During the production process, the charging time is determined according to the position of the burden surface at the top of the blast furnace. The weight of coke added each time for blast furnace charging is 21 t. The coke is lifted to the bunker through the charging device, and then the angle of the rotary chute is adjusted between 12° and 40°, and multi-ring charging is carried out in 5 gears. The coke is arranged in a flat form from the edge to the center of the furnace wall on the original burden surface at the top of the blast furnace. After the coke is charged, 23 t of acidic pellets are lifted to the bunker through the charging device, and then the angle of the rotary chute is adjusted between 34 - 43°, and multi-ring charging is carried out in 2 gears. The acidic pellets are distributed to the set area near the edge of the blast furnace on the coke layer. After the acidic burden is charged, 67 tons of high-alkali sinter are lifted to the bunker through the charging device, and then the angle of the rotary chute is adjusted between 30 - 40°, and multi-ring charging is carried out in 4 gears. The high-alkali sinter is distributed to the area near the center of the blast furnace on the coke layer and the acidic burden layer.

[0042] The initial softening temperature of the high-alkalinity sinter is 1230°C, and the melting temperature is 1400°C. The initial softening temperature of the acid pellet is 970°C, and the melting temperature is 1290°C. When using the traditional all-region charging of sinter and pellets, the initial softening temperature of the mixed ore is 970°C, the melting temperature is 1400°C, and the softening and dripping temperature range is 430°C. When using the charging method of separating the burden materials into different regions in the blast furnace, the central region of the blast furnace is charged with high-alkalinity sinter, and the softening and dripping temperature range is 170°C. The edge region is charged with acid pellets, and the softening and dripping temperature range is 320°C. The softening and dripping temperature ranges in different regions have all decreased significantly, resulting in a substantial thinning of the cohesive zone in the blast furnace, better permeability of the blast furnace, a reduction in the blast furnace differential pressure, an improvement in the distribution of the coal gas flow, an increase in the utilization rate of the gas, a reduction in the fuel ratio of the blast furnace, an increase in production, and a simultaneous reduction in the carbon emissions of the blast furnace. The application effect of Example 2 is shown in Table 4.

[0043] Table 4: Application effect of the blast furnace

[0044]

[0045] In a 2500 m 3 After the implementation of the blast furnace, by separating the charging of high-alkalinity sinter and acid pellets into different regions, the thickness of the cohesive zone has been effectively reduced, the permeability of the blast furnace has been improved, achieving a good operating effect of reducing the blast furnace differential pressure by 6 kPa, increasing the gas utilization rate by 0.7%, reducing the fuel ratio by 11 kg / tHM, increasing the daily output by 125 t, and saving the molten iron cost by 35 yuan, realizing low fuel ratio, high efficiency, and low-carbon emission smelting in the blast furnace.

[0046] Application Example 3

[0047] For a 3500 m 3 blast furnace in a steel plant, the burden structure of the blast furnace is the smelting with high-alkalinity sinter in combination with acid pellets. The method of separating the charging of different burden materials into different regions and the method of superimposing and reducing the thickness of the softening interval are completed according to the following steps:

[0048] Adopt the bell-less top charging. According to the position of the burden surface at the top of the blast furnace, use the charging modes of coke, acid burden materials, and basic burden materials respectively for the cyclic charging of the burden materials into the furnace;

[0049] The coke is spread evenly on the original burden surface at the top of the blast furnace through the rotary chute. The acid burden materials are distributed on the coke layer in the area close to the edge of the blast furnace through the rotary chute. The basic burden materials are distributed on the coke layer in the area close to the center of the blast furnace through the rotary chute. Thus, the charging in the furnace is completed. The physical properties of the coke, basic burden materials, and acid burden materials used in the blast furnace smelting are shown in Table 5.

[0050] Table 5: Physical properties of the coke, basic burden materials, and acid burden materials used in the blast furnace smelting

[0051] The burden structure used in blast furnace smelting is 60% high-alkali sinter + 40% acid pellet. During the production process, the charging time is determined according to the position of the burden surface at the top of the blast furnace. Each time coke is added during blast furnace burden distribution, the weight is 30t. The coke is lifted to the bunker by the charging device, and then the angle of the revolving chute is adjusted between 11° and 42°, and multi-ring burden distribution is carried out in 6 gears. The coke is laid flat from the edge to the center of the furnace wall and arranged on the original burden surface at the top of the blast furnace. After the coke is distributed, 60t of acid pellets are lifted to the bunker by the charging device, and then the angle of the revolving chute is adjusted between 35° and 45°, and multi-ring burden distribution is carried out in 3 gears. The acid pellets are distributed on the coke layer in a set area near the edge of the blast furnace. After the acid burden is distributed, 90 tons of high-alkali sinter are lifted to the bunker by the charging device, and then the angle of the revolving chute is adjusted between 30° and 40°, and multi-ring burden distribution is carried out in 3 gears. The high-alkali sinter is distributed on the coke layer in the area near the center of the blast furnace.

[0052] The initial softening temperature of the high-alkali sinter is 1240°C, and the melting temperature is 1450°C. The initial softening temperature of the acid pellet is 1010°C, and the melting temperature is 1320°C. When using the traditional all-region burden distribution of sinter and pellet, the initial softening temperature of the mixed ore is 1010°C, the melting temperature is 1450°C, and the softening, melting and dripping temperature range is 440°C. When using the burden distribution by separating charging and seeking regions in the blast furnace, the central region is high-alkali sinter, and the softening, melting and dripping temperature range is 210°C. The edge region is acid pellet, and the softening, melting and dripping temperature range is 310°C. The softening, melting and dripping temperature ranges in different regions have all decreased significantly, resulting in a significant thinning of the softening-melting zone in the blast furnace, better permeability of the blast furnace, lower blast furnace differential pressure, improved distribution of the coal gas flow, increased utilization rate of the coal gas, reduced fuel ratio in the blast furnace, increased output, and at the same time reduced the carbon emissions of the blast furnace. The application effect of Example 3 is shown in Table 6.

[0053] Table 6: Application effect of blast furnace

[0054] In a 3500m 3 After the implementation of the blast furnace, by separating the charging and seeking regions of the high-alkali sinter and the acid pellet, the thickness of the softening-melting zone is effectively reduced, the permeability of the blast furnace is improved, achieving a good operation effect of reducing the blast furnace differential pressure by 9 kPa, increasing the utilization rate of the coal gas by 0.5%, reducing the fuel ratio by 8 kg / tHM, increasing the daily output by 150t, and saving the molten iron cost by 48 yuan, realizing low fuel ratio, high efficiency and low carbon emission smelting in the blast furnace.

[0055] Application of Example 4

[0056] A certain iron and steel plant with a volume of 4600m 3The blast furnace has a burden structure of high basicity sinter mixed with acid pellet for smelting. The method of separate charging, domain-based distribution and superposition-thinning in the softening-melting zone is completed according to the following steps:

[0057] The bell-less top charging is adopted. According to the position of the burden surface at the top of the blast furnace, the charging modes of coke, acid burden and basic burden are respectively used for the cyclic charging of the burden into the furnace.

[0058] The coke is spread flat on the original burden surface at the top of the blast furnace through the rotary chute. The acid burden is distributed through the rotary chute in the area near the edge of the blast furnace on the coke layer. The basic burden is distributed through the rotary chute in the area near the center of the blast furnace on the coke layer. Thus, the burden distribution in the furnace is completed. The physical properties of the coke, basic burden and acid burden used in the blast furnace smelting are shown in Table 7.

[0059] Table 7: Physical properties of coke, basic burden and acid burden used in blast furnace smelting

[0060] The burden structure used in the blast furnace smelting is 50% high basicity sinter + 50% acid pellet. During the production process, the charging time is determined according to the position of the burden surface at the top of the blast furnace. The weight of coke added each time for the blast furnace burden distribution is 38t. The coke is lifted to the bunker through the charging device, and then the angle of the rotary chute is adjusted between 9° and 43°, and multi-ring distribution is carried out in 7 gears. The coke is arranged in a flat form from the edge to the center of the furnace wall on the original burden surface at the top of the blast furnace. After the coke is distributed, 95t of acid pellet is lifted to the bunker through the charging device, and then the angle of the rotary chute is adjusted between 37 - 46°, and multi-ring distribution is carried out in 4 gears. The acid pellet is distributed to the set area near the edge of the blast furnace on the coke layer. After the acid burden is distributed, 95 tons of high basicity sinter is lifted to the bunker through the charging device, and then the angle of the rotary chute is adjusted between 34 - 40°, and multi-ring distribution is carried out in 3 gears. The high basicity sinter is distributed to the area near the center of the blast furnace on the coke layer.

[0061] The initial softening temperature of the high basicity sinter used is 1210°C, and the melting temperature is 1400°C. The initial softening temperature of the acid pellet is 1000°C, and the melting temperature is 1330°C. When the traditional all-domain distribution of sinter and pellet is adopted, the initial softening temperature of the mixed ore is 1000°C, the melting temperature is 1400°C, and the softening-dripping temperature range is 400°C. When the separate charging and domain-based distribution is adopted in the blast furnace, the high basicity sinter is in the central area of the blast furnace, and the softening-dripping temperature range is 190°C. The acid pellet is in the edge area, and the softening-dripping temperature range is 300°C. The softening-dripping temperature ranges in different areas have all decreased significantly, resulting in a significant thinning of the softening-melting zone in the blast furnace, better permeability of the blast furnace, lower blast furnace pressure difference, improved distribution of the coal gas flow, increased utilization rate of the coal gas, reduced blast furnace fuel ratio, increased output, and at the same time reduced the carbon emissions of the blast furnace. The application effect of Example 4 is shown in Table 8.

[0062] Table 8: Application Effect of Blast Furnace

[0063] After the implementation in a 4600 m 3 blast furnace, by separately charging and distributing high - basicity sinter and acidic pellet in the search area, the thickness of the soft - melting zone was effectively reduced, the permeability of the blast furnace was improved, achieving a good operation effect of reducing the blast - furnace differential pressure by 6 kPa, increasing the gas utilization rate by 0.5%, reducing the fuel ratio by 8 kg / tHM, increasing the daily output by 100 t, and saving the hot - metal cost by 54 yuan, realizing low - fuel - ratio, high - efficiency, and low - carbon - emission smelting in the blast furnace.

[0064] Application Example 5

[0065] In a 5500 m 3 blast furnace of a steel plant, the burden structure of the blast furnace is smelted with high - basicity sinter combined with acidic pellet. The method of separately charging and distributing different burden in the search area and reducing the thickness by superimposing in the soft - melting zone is completed according to the following steps:

[0066] Adopt the bell - less top charging. According to the position of the burden surface at the top of the blast furnace, the charging mode of separately charging coke, acidic burden, and basic burden is adopted for the burden to circulate into the furnace;

[0067] The coke is spread flat on the original burden surface at the top of the blast furnace through the rotary chute. The acidic burden is distributed by the rotary chute in the area near the edge of the blast furnace on the coke layer, and the basic burden is distributed by the rotary chute in the area near the center of the blast furnace on the coke layer. Thus, the burden charging in the furnace is completed. The physical properties of the coke, basic burden, and acidic burden used in the blast - furnace smelting are shown in Table 9.

[0068] Table 9: Physical Properties of Coke, Basic Burden, and Acidic Burden Used in Blast - Furnace Smelting

[0069]

[0070] The burden structure used in blast furnace smelting is 50% high-alkali sinter + 40% acid pellet + 10% lump ore. During the production process, the charging time is determined according to the position of the burden surface at the top of the blast furnace. The weight of coke added each time for blast furnace burden distribution is 45t. The coke is lifted to the bunker through the feeding device, and then the angle of the rotating chute is adjusted between 8° and 45°, and multi-ring burden distribution is carried out in 7 gears. The coke is arranged in a tiled form from the edge to the center of the furnace wall on the original burden surface at the top of the blast furnace. After the coke is distributed, 88t of acid pellets and 22t of lump ore are lifted to the bunker through the feeding device, and then the angle of the rotating chute is adjusted between 38 - 47°, and multi-ring burden distribution is carried out in 4 gears. The acid pellets are distributed to the set area near the edge of the blast furnace on the coke layer. After the acid burden is distributed, 110t of high-alkali sinter is lifted to the bunker through the feeding device, and then the angle of the rotating chute is adjusted between 36 - 42°, and multi-ring burden distribution is carried out in 3 gears. The high-alkali sinter is distributed to the area near the center of the blast furnace on the coke layer.

[0071] The initial softening temperature of the high-alkali sinter is 1180°C, and the melting temperature is 1380°C. The initial softening temperature of the acid pellet is 1030°C, and the melting temperature is 1300°C. The initial softening temperature of the lump ore is 1040°C, and the melting temperature is 1320°C. When using the traditional all-region burden distribution of sinter and pellets, the initial softening temperature of the mixed ore is 1030°C, the melting temperature is 1380°C, and the softening and dripping temperature range is 350°C. When using the burden distribution by separate charging and seeking regions in the blast furnace, the center region is high-alkali sinter, and the softening and dripping temperature range is 200°C. The edge region is acid pellets, and the softening and dripping temperature range is 260°C. The softening and dripping temperature ranges in different regions have decreased significantly, resulting in a significant thinning of the softening zone in the blast furnace, better permeability of the blast furnace, a decrease in the blast furnace differential pressure, an improvement in the distribution of the coal gas flow, an increase in the utilization rate of the coal gas, a reduction in the blast furnace fuel ratio, an increase in production, and at the same time a reduction in the carbon emissions of the blast furnace. The application effect of Application Example 5 is shown in Table 10.

[0072] Table 10: Application Effect of Blast Furnace

[0073] At 5500m 3 After the implementation of the blast furnace, through the separate charging and seeking regions of the high-alkali sinter and acid pellets, the thickness of the softening zone has been effectively reduced, the permeability of the blast furnace has been improved, achieving a good operating effect of reducing the blast furnace differential pressure by 5 kPa, increasing the utilization rate of the coal gas by 0.4%, reducing the fuel ratio by 9 kg / tHM, increasing the daily output by 130t, and saving the molten iron cost by 55 yuan, realizing low fuel ratio, high efficiency, and low carbon emission smelting in the blast furnace.

[0074] The above description is only an illustrative embodiment of the present invention and does not impose any formal or substantial limitations on the present invention. It should be noted that for those of ordinary skill in the art, without departing from the method of the present invention, several improvements and supplements made should also be regarded as within the protection scope of the present invention; at the same time, any equivalent changes, modifications, and evolutions made to the above embodiments based on the essential technology of the present invention still fall within the protection scope of the present invention.

Claims

1. A method for separately loading furnace charge, searching for domain distribution and removing superposition in the softening and melting zone, characterized in that, The method includes the following steps: Step 1: Adopt the bell-less top charging method. According to the position of the burden surface at the top of the blast furnace, use the charging modes of coke, acidic burden, and basic burden respectively for the cyclic charging of the burden into the furnace; Step 2: The coke is spread evenly on the original burden surface at the top of the blast furnace through the revolving chute. The acidic burden is distributed on the area near the edge of the blast furnace on the coke layer through the revolving chute. The basic burden is distributed on the area near the center of the blast furnace on the coke layer through the revolving chute. Thus, the burden distribution and area-finding charging are completed; In Step 1, the average particle size of the coke is greater than 35 mm, M40 is greater than 80%, M10 is less than 8%, CSR is greater than 60%, and CRI is less than 26%; In Step 1, the acidic burden is pellet ore, lump ore, and the mixture of both. The basicity is less than 0.8, the iron grade is greater than 60%, the average particle size is greater than 12 mm, the starting softening temperature of the acidic burden is 870 - 1050 °C, and the melting temperature is 1150 - 1250 °C; In Step 1, the basic burden is high-basicity sinter, the basicity is greater than 1.7, the iron grade is greater than 52%, the average particle size is greater than 15 mm, the starting softening temperature is 1100 - 1200 °C, and the melting temperature is 1300 - 1380 °C; In Step 2, the acidic burden is lifted to the skip hopper through the charging device. By adjusting the angle of the revolving chute to 35 - 45°, the acidic burden is distributed to the set edge area above the coke layer by the multi-ring charging method. The acidic burden in this area starts to soften until it drops to the position where it intersects with the 900 °C isothermal line of the basic burden column; In Step 2, the basic burden is lifted to the skip hopper through the charging device. By adjusting the angle of the revolving chute to 30 - 45°, the basic burden is distributed to the coke layer and the acidic burden layer by the multi-ring charging method; In Step 2, the softening temperature and melting temperature of the basic burden are high, while those of the acidic burden are low. When the two kinds of burdens are mixed and charged, the softening intervals overlap, that is, the softening temperature of the mixed burden is the lower limit of the softening temperatures of the two kinds of burdens, and the melting temperature takes the upper limit of the melting temperatures of the two kinds of burdens, resulting in an increase in the softening temperature range and the thickness of the softening zone of the mixed burden. When the basic burden and the acidic burden are charged separately and area-finding charging is adopted, the starting softening temperature line of the blast furnace burden column is mostly formed in the basic burden area. The acidic burden starts to soften only when it drops to the root position of the softening zone where it intersects with the 900 °C softening characteristic temperature. The softening temperatures of the two kinds of burdens do not overlap in most parts of the softening zone, and only a very small part at the root of the softening zone has an overlap. The thickness of the blast furnace softening zone decreases, and the decreased temperature range is: characteristic temperature 1150 °C - characteristic temperature 900 °C = 250 °C.

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