Blast furnace smelting method for increasing yield and reducing consumption based on high slag ratio condition

Abstract

The invention discloses a blast furnace smelting method for increasing yield and reducing consumption based on a high slag ratio condition, and belongs to the technical field of blast furnace smelting. According to the method, the proportion of sintered ore, magnesian pellet ore and lump ore is optimized, specific stock bin management and a small-batch inferior ore fixed-bin feeding mode are adopted, furnace entering components are stabilized, the air volume, the air speed, the coal ratio, the pressure difference and top pressure are regulated and controlled, oxygen-enriched hot air is blown in, and slag iron discharge is promoted in a zero-interval tapping mode. According to the method, high-efficiency and stable smooth operation can be realized under the conditions of low grade and high slag ratio, the yield is obviously improved, and the fuel consumption is reduced.

Description

Technical Field

[0001] This invention relates to the field of blast furnace smelting technology, specifically to a blast furnace smelting method for increasing production and reducing energy consumption under high slag ratio conditions. Background Technology

[0002] Blast furnace smelting is the core process of modern steel production, and its technical and economic indicators directly affect the energy consumption, cost, and overall competitiveness of steel enterprises. For a long time, refined feed technology has been considered the foundation of efficient blast furnace smelting, especially for large and medium-sized blast furnaces. This requires high-grade ore and low slag content (the slag ratio is typically controlled below 300 kg / t) to achieve good charge permeability and reduction kinetics, ensuring stable blast furnace operation and reducing fuel consumption. By adopting high-grade lump ore, a high proportion of pellets, and optimized sintering blends, advanced enterprises can achieve high utilization coefficients, low fuel ratios, and long furnace lifespans.

[0003] In actual production, many steel companies are constrained by raw material procurement costs, regional resource endowments, and supply chain stability, making it impossible to consistently achieve high-standard refined material operations. Especially against the backdrop of volatile iron ore prices and weak resource security, many blast furnaces have long used low- to medium-grade ore (generally below 57% grade), resulting in a significantly increased slag ratio (generally reaching 395-415 kg / t). This high slag ratio not only exacerbates the risk of flooding in the furnace and hinders gas flow distribution, but also leads to increased heat loss and a higher coke ratio, making it difficult for blast furnaces to achieve high-intensity smelting, and resulting in production technical indicators significantly lower than the industry's advanced levels. Therefore, how to overcome the constraints of traditional refined materials and develop smelting control technologies suitable for high slag ratio conditions has become a critical issue urgently needing to be addressed in the blast furnace field. Summary of the Invention

[0004] To address the problem of low technical indicators in blast furnace smelting under high slag ratio conditions, this invention provides a blast furnace smelting method for increasing production and reducing consumption under high slag ratio conditions. This method can promote increased blast furnace output and utilization coefficient, reduce blast furnace fuel ratio and coke ratio, and achieve efficient smelting by using low-grade, high-slag-ratio ores to improve blast furnace production technical indicators to above the industry average.

[0005] The blast furnace smelting method for increasing production and reducing energy consumption according to the present invention specifically includes the following steps: (1) Mix sinter, magnesia pellets and lump ore to obtain iron-containing raw materials, and load coke and iron-containing raw materials into a blast furnace to obtain a mixed raw material system.

[0006] (2) The process of emptying the silo → replacing the old material → mixing the new material and the old material and then feeding the furnace with completely new material is adopted to ensure the stability of the composition of the sinter when the high proportion of sinter is replaced. At the same time, heterogeneous or inferior sinter is supplied to the blast furnace trough to stabilize the composition and quality of the sinter entering the furnace and avoid fluctuations in furnace conditions caused by abnormal quality ore entering the furnace.

[0007] (3) Block the three air vents above the iron tap, and use Φ120mm air vents for the remaining air vents to ensure even air intake.

[0008] (4) Adjust the coal ratio, pressure difference and top pressure to stabilize the furnace operation.

[0009] (5) Blow oxygen-rich hot air into the blast furnace to maintain the theoretical combustion temperature.

[0010] (6) The zero-interval tapping mode is adopted to separate molten iron and slag for cyclic smelting operation.

[0011] Preferably, in step (1) of the present invention, the sinter grade is ≥54% and the drum grade is ≥79%.

[0012] Preferably, in step (1) of the present invention, the magnesium pellets have a grade of ≥59%, a compressive strength of ≥2000N / piece, and an MgO content of 1.0-1.5%.

[0013] Preferably, in step (1) of the present invention, the coke has a CRI ≤ 25%, CSR ≥ 67%, M40 ≥ 88%, and M10 ≤ 6%.

[0014] Preferably, in step (1) of the present invention, the mass percentage of sintered ore in each batch of iron-containing raw materials is 68%~74%, the mass percentage of magnesium pellets is 23%~27%, and the remainder is lump ore.

[0015] Preferably, in step (1) of the present invention, the magnesium-aluminum ratio in the mixed raw material system is 0.65~0.75, and the mass percentage of MgO in the mixed raw material system is 7.0%~9.0%.

[0016] Preferably, in step (2) of the present invention, the amount of heterogeneous or inferior sintered ore supplied is ≤3t / batch.

[0017] Preferably, in step (2) of the present invention, the batch of ore fed into the furnace is 54-56 t / batch, and the average feed rate is 9.0-9.5 batches / h; if the average feed rate over 24 hours is lower than 9.0 batches / h, the batch size should be appropriately reduced to 52-55 t / batch in order to maintain a suitable feed rate and smooth furnace operation.

[0018] Preferably, in step (2) of the present invention, the new material and the old material are mixed into the furnace in a pattern of 20%~100% / 80%~0→100% / 0 mass percentage of new material / old material, so as to gradually realize the replacement of the two types of sintered ore materials.

[0019] Preferably, the uniform air intake condition in step (3) of the present invention is: an average air volume of 4600~4700 m³ / h. 3 / min, wind speed is 240~260m / s.

[0020] Preferably, in step (3) of the present invention, the amount of gas in the furnace belly is 6100~7100m³. 3 / min.

[0021] Preferably, the pulverized coal injection ratio in step (4) of the present invention is 140~145 kg / t.

[0022] Preferably, in step (4) of the present invention, the pressure difference is the difference between the hot air pressure and the furnace top pressure, the pressure difference is ≤185Kpa, and the furnace top pressure is 0-10Kpa higher than the pressure difference.

[0023] Preferably, the oxygen enrichment rate in step (5) of the present invention is 4.80% to 5.50%.

[0024] Preferably, the hot air temperature in step (5) of the present invention is 1150-1220°C.

[0025] Preferably, the theoretical combustion temperature in step (5) of the present invention is 2350-2530℃.

[0026] In step (6) of this invention, if no slag is seen after 30 minutes of tapping iron from the blast furnace, iron should be tapped in parallel from the other side of the taphole in a timely manner to promote the discharge of slag and iron.

[0027] Compared with the prior art, the present invention provides a blast furnace smelting method for increasing production and reducing consumption under high slag ratio conditions, which has the following beneficial effects: The blast furnace of this invention achieves an average daily qualified pig iron production of over 7000 t / d under conditions of an average charge grade of 55.99–56.81% and a slag ratio as high as 397–413 kg / t. The effective volume utilization coefficient is increased by 0.256 t / (m³·d) compared to the previous year, while the coke ratio and fuel ratio are both reduced by 8 kg / t. Furthermore, the blast furnace utilization coefficient, fuel ratio, and coke ratio are all superior to the industry average, enabling the blast furnace to achieve efficient production and smelting under high slag ratio conditions. Detailed Implementation

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] In the embodiments and comparative examples of this invention, the sintered ore drum has a ≥79% content, the magnesia pellet compressive strength is ≥2000N / piece, and the coke CRI is ≤25%, CSR is ≥67%, M40 is ≥88%, and M10 is ≤6%. The coke and iron-containing raw materials are charged using the conventional coke-iron-containing raw material charging mode.

[0030] Example 1 In this embodiment, the overall grade of the ore used in the furnace is 55.99%, and the slag ratio is 412.70 kg / t. The specific smelting steps are as follows: (1) Iron-bearing raw materials are obtained by mixing sinter, magnesia pellets and lump ore. The mass percentage content of sinter in the iron-bearing raw materials is 73.8%, the mass percentage content of magnesia pellets is 23.7%, and the mass percentage content of lump ore is 2.5%. Coke and iron-bearing raw materials are charged into a blast furnace to obtain a mixed raw material system. The average amount of coke added is 12.2t / batch. The magnesium-aluminum ratio in the mixed raw material system is 0.67, and the mass percentage content of MgO in the mixed raw material system is 7.75%.

[0031] (2) The process of emptying the sintering silos → replacing old materials → mixing new and old materials and feeding them into the furnace → feeding them entirely with new materials is adopted. The batches of ore fed into the furnace are 55t / batch and 56t / batch, and the average feeding rate is 9.0 batches / h. Specifically, during the five sintering silo replacement processes throughout the month, silos 2 to 5A are used in a concentrated manner before the replacement to prepare for the supply of new materials. After the new materials are fed into the silos, silos 2 to 5A are used in a concentrated manner twice more to ensure that all materials in this part of the silos are replaced with new materials. After that, the process is started. Using the remaining material bins and reducing the amount used in bins 2-5A, a transitional mixing and feeding mode was adopted, with the new / old material mixing ratio of 20% / 80% → 60% / 40% → 100% / 0, to gradually replace the new and old sintered ore. At the same time, bin 11A was used as a bin for small-particle sintered ore and used at a fixed rate of 0.55t / batch, ensuring the relative stability of the material quality. The furnace operation was stable and smooth throughout the month during the blast furnace replacement and the use of small-particle sintered ore.

[0032] (3) Move the 1 above the blast furnace taphole # 12 # 19 # With the air vents blocked, the remaining 27 air vents will use Φ120mm vents for even air intake, with an intake area of ​​0.3054m². 2 The average air volume is 4628 m³ / min, the gas volume in the furnace belly is 6852 m³ / min, and the wind speed is 242 m / s.

[0033] (4) The average pulverized coal injection ratio of the blast furnace is 144.66 kg / t, the pressure difference is 180 kPa, the top pressure is 185 kPa, the permeability index of the material column is 25711 m³ / min·Mpa, and the furnace is operating smoothly under stable conditions.

[0034] (5) Inject oxygen-enriched hot air into the blast furnace. The oxygen enrichment rate in the blast furnace is 4.8%, the average oxygen enrichment is 18100 m³ / h, the average blast temperature is 1150℃, and the theoretical combustion temperature is 2350℃. Under these conditions, low-silicon smelting is achieved, the mass percentage of silicon in the molten iron is 0.34%, and the average temperature of the molten iron is as high as 1474℃.

[0035] (6) The zero-interval tapping mode is adopted to separate molten iron and slag for cyclic smelting operation.

[0036] Under the blast furnace smelting method of this embodiment, with an average charge grade of 55.99% and a slag ratio of 412.70 kg / t, the slag exhibited good fluidity, achieving efficient and stable operation. The zero-interval tapping mode resulted in a slag-to-slag ratio as high as 89.61%, ensuring timely and effective slag and iron discharge without any air blockage caused by incomplete slag and iron removal. No pipeline travel occurred throughout the month, with only one instance of suspended material. Ultimately, a daily qualified pig iron production of 7022.03 t and an effective volume utilization coefficient of 2.809 t / (m³) were achieved. 3 •d) The goal of high-efficiency smelting with a coke ratio of 367.17 kg / t and a fuel ratio of 510.84 kg / t.

[0037] Example 2 In this embodiment, the overall grade of the ore used in the furnace is 56.12%, and the slag ratio is 412.70 kg / t. The specific smelting steps are as follows: (1) Iron-bearing raw materials are obtained by mixing sinter, magnesia pellets and lump ore. The mass percentage content of sinter in the iron-bearing raw materials is 68.8%, the mass percentage content of magnesia pellets is 27.0%, and the mass percentage content of lump ore is 4.2%. Coke and iron-bearing raw materials are charged into a blast furnace to obtain a mixed raw material system. The average amount of coke added is 11.5t / batch. The magnesium-aluminum ratio in the mixed raw material system is 0.69, and the mass percentage content of MgO in the mixed raw material system is 7.8%.

[0038] (2) The process of emptying the sintering silo → replacing the old material → mixing the new and old materials and feeding them into the furnace → feeding them with completely new materials is adopted. The batches of ore fed into the furnace are 55t / batch and 56t / batch, and the average feeding rate is 9.2 batches / h. Specifically, during the 5 replacements of sintering sintering slabs throughout the month, silos 2 to 5A are used in a concentrated manner before the replacement to prepare for the supply of new materials. After the new materials are fed into the silos, silos 2 to 5A are used in a concentrated manner twice more to achieve the replacement of all sintering slabs in this part with new materials. After that, the remaining silos are used and the amount of silos 2 to 5A is reduced. The transitional mixing feeding mode is adopted according to the mixing ratio of new material / old material as 20% / 80% → 50% / 50% → 60% / 40% → 100% / 0. The replacement of the two types of sintering ore is gradually realized to ensure the relative stability of the quality of the raw materials fed into the furnace. The furnace condition is stable and smooth during the sintering slab replacement process throughout the month.

[0039] (3) Move the 1 above the blast furnace taphole # 12 # 19 # With the air vents blocked, the remaining 27 air vents will use Φ120mm vents for even air intake, with an intake area of ​​0.3054m². 2The average air volume is 4656 m³ / min, the gas volume in the furnace belly is controlled at 6364 m³ / min, and the wind speed is 258 m / s.

[0040] (4) Adjust the average pulverized coal injection ratio of the blast furnace to 142.17 kg / t, the pressure difference to 181 kPa, the top pressure to 189 kPa, and the permeability index of the material column to 25724 m³ / min·Mpa, and stabilize the furnace operation.

[0041] (5) Oxygen-enriched hot air is blown into the blast furnace. The oxygen enrichment rate in the blast furnace is 5.07%, the average oxygen enrichment is 18963 m³ / h, the average blast temperature is 1198℃, and the theoretical combustion temperature is 2501℃. Under these conditions, low silicon smelting is achieved, the mass percentage of silicon in the molten iron is 0.31%, and the average temperature of the molten iron is as high as 1470℃.

[0042] (6) The zero-interval tapping mode is adopted to separate molten iron and slag for cyclic smelting operation.

[0043] Under the blast furnace smelting method of this embodiment, with an average charge grade of 56.12% and a slag ratio of 407.97 kg / t, the slag exhibited good fluidity, achieving efficient and stable operation. The zero-interval tapping mode resulted in a slag-to-slag ratio as high as 87.30%, ensuring timely and effective slag and iron discharge without any air blockage caused by incomplete slag and iron removal. No pipework or suspended material issues occurred throughout the month, ultimately achieving a daily qualified pig iron production of 7162.54 t and an effective volume utilization coefficient of 2.865 t / (m²). 3 •d) The goal of high-efficiency smelting with a coke ratio of 372.66 kg / t and a fuel ratio of 514.83 kg / t.

[0044] Example 3 In this embodiment, the overall grade of the ore used in the furnace is 56.81%, and the slag ratio is 397.36 kg / t. The specific smelting steps are as follows: (1) Iron-bearing raw materials are obtained by mixing sinter, magnesia pellets and lump ore. The mass percentage content of sinter in the iron-bearing raw materials is 73.8%, the mass percentage content of pellets is 23.7%, and the mass percentage content of lump ore is 2.5%. Coke and iron-bearing raw materials are charged into a blast furnace to obtain a mixed raw material system. The amount of coke added is 11.8-12.1 t / batch. The magnesium-aluminum ratio in the mixed raw material system is 0.75, and the mass percentage content of MgO in the mixed raw material system is 8.17%.

[0045] (2) The process of emptying the sintering silos → replacing old materials → mixing new and old materials and feeding them into the furnace → feeding them entirely with new materials is adopted. The batches of ore fed into the furnace are 55t / batch and 54t / batch, and the average feeding rate is 9.2 batches / h. Specifically, during the sintering silo replacement process four times a month, silos 2 to 5A are used in a concentrated manner before the replacement to prepare for the supply of new materials. After the new materials are fed into the silos, silos 2 to 5A are used in a concentrated manner twice more to achieve the complete replacement of these silos with new materials. After that, the process is started. Using the remaining material from the silos and reducing the amount used in silos 2-5A, a transitional mixing and feeding mode is adopted, with the new / old material mixing ratio being 20% / 80% → 50% / 50% → 60% / 40% → 100% / 0, to gradually replace the new and old sintered ore. At the same time, abnormal sintered ore with high or low basicity is supplied to silo 11A and gradually consumed at a fixed rate of 2.5t / batch to ensure the relative stability of the quality of raw materials entering the furnace.

[0046] (3) Move the 1 above the blast furnace taphole # 12 # 19 # With the air vents blocked, the remaining 27 air vents will use Φ120mm vents for even air intake, with an intake area of ​​0.3054m². 2 The average air volume is 4663 m³ / min, the gas volume in the furnace belly is controlled at 7033 m³ / min, and the wind speed is 254 m / s.

[0047] (4) The average pulverized coal injection ratio of the blast furnace is 140.17 kg / t, the pressure difference is 182 kPa, the top pressure is 189 kPa, the permeability index of the material column is 25621 m³ / min·Mpa, and the furnace is operating smoothly under stable conditions.

[0048] (5) Inject oxygen-enriched hot air into the blast furnace. The oxygen enrichment rate in the blast furnace is 5.5%, the average oxygen enrichment is 20800 m³ / h, the average blast temperature is 1220℃, and the theoretical combustion temperature is 2530℃. Under these conditions, low-silicon smelting is achieved. The mass percentage of silicon in the molten iron is 0.35%, and the average temperature of the molten iron is as high as 1473℃.

[0049] (6) The zero-interval tapping mode is adopted to separate molten iron and slag for cyclic smelting operation.

[0050] Under the blast furnace smelting method of this embodiment, with an average charge grade of 56.81% and a slag ratio of 397.36 kg / t, the slag exhibited good fluidity, achieving efficient and stable operation. The zero-interval tapping mode resulted in a slag-to-slag ratio as high as 83.11%, ensuring timely and effective slag and iron discharge without any air blockage caused by incomplete slag and iron removal. No pipeline travel occurred throughout the month, with only one instance of suspended material. Ultimately, a daily qualified pig iron production of 7150.61 t and a utilization coefficient of 2.860 t / (m³) were achieved. 3•d) The goal of high-efficiency smelting with a coke ratio of 371.65 kg / t and a fuel ratio of 514.25 kg / t.

[0051] Comparative Example 1 The ore used in this comparative example has an overall grade of 56.02% and a slag ratio of 409.61 kg / t. The specific smelting steps are as follows: (1) Iron-bearing raw materials are obtained by mixing two types of ores: sinter and ordinary pellets. The mass percentage content of sinter in the iron-bearing raw materials is 76.3%, and the mass percentage content of pellets is 23.7%. The magnesium-aluminum ratio in the mixed raw material system is 0.63. Coke and iron-bearing raw materials are loaded into a blast furnace to obtain a mixed raw material system. The amount of coke added is 11.8 to 11.9 t / batch.

[0052] (2) The furnace was fed with a completely old material → completely new material mode. The batches of ore fed into the furnace were 54t / batch and 53t / batch, with an average feeding rate of 8.9 batches / h. No special treatment was given to abnormal sintered ore with high or low basicity throughout the month.

[0053] (3) Block 3 air vents, but use Φ115mm air vents for the remaining 27 air vents, with staggered air intake, an average air volume of 5028m³ / min, an air velocity of 278m / s, and an air intake area of ​​0.2805m². 2 .

[0054] (4) The average pulverized coal injection ratio of the blast furnace was adjusted to 149.50 kg / t, the pressure difference was 194 kPa, the top pressure was 190 kPa, the permeability index of the material column was 25918 m³ / min.Mpa, and the furnace operation was stable and smooth.

[0055] (5) Inject oxygen-enriched hot air into the blast furnace. The oxygen enrichment rate in the blast furnace is 4.55%, the average oxygen enrichment is 17311 m³ / h, the average blast temperature is 1207℃, and the theoretical combustion temperature is 2476℃. The mass percentage of silicon in the molten iron is 0.37%, and the average temperature of the molten iron is as high as 1469℃.

[0056] (6) Use a tapping mode with a 10-minute interval to separate molten iron and slag for cyclic smelting.

[0057] In this embodiment of the blast furnace smelting method, under the conditions of an average charge grade of 56.02% and a slag ratio of 409.61 kg / t, the blast furnace operated relatively smoothly, but experienced three instances of charge suspension. The daily qualified pig iron output was only 6807.29 t, and the effective volume utilization coefficient was 2.723 t / (m²). 3 ·d) The fuel ratio was 519.44 kg / t, the blast furnace condition fluctuated, the blast furnace output was low, the fuel ratio was high, and the production efficiency was low.

[0058] Comparative Example 2 The ore used in this comparative example has an overall grade of 56.07% and a slag ratio of 407.75 kg / t. The specific smelting steps are as follows: (1) Iron-bearing raw materials are obtained by mixing sinter, magnesia pellets and lump ore. The mass percentage content of sinter in the iron-bearing raw materials is 74.6%, the mass percentage content of magnesia pellets is 22.4%, and the mass percentage content of lump ore is 3.0%. Coke and iron-bearing raw materials are charged into a blast furnace to obtain a mixed raw material system. The amount of coke added is 11.7 to 11.9 t / batch. The magnesium-aluminum ratio in the mixed raw material system is 0.64.

[0059] (2) The furnace was fed with a completely old material → completely new material mode. The batches of ore fed into the furnace were 51t / batch, 52t / batch and 53t / batch, with an average feeding rate of 9.1 batches / h. No special treatment was given to abnormal sintered ore with high or low basicity throughout the month.

[0060] (3) 9 # 19 # 30 # and 14 # With the main air vent blocked, the remaining vents use Φ110mm vents, staggered for air intake, with an average air volume of 4273m³ / min, an air velocity of 240m / s, and an intake area of ​​0.2471m². 2 .

[0061] (4) The average pulverized coal injection ratio of the blast furnace was adjusted to 137.77 kg / t, the pressure difference was 182 kPa, the top pressure was 180 kPa, the permeability index of the material column was 23478 m³ / min.Mpa, and the furnace operation was smooth.

[0062] (5) Inject oxygen-enriched hot air into the blast furnace. The oxygen enrichment rate in the blast furnace is 4.74%, the average oxygen enrichment is 16943 m³ / h, the average blast temperature is 1200℃, the theoretical combustion temperature is 2495℃, the mass percentage of silicon in the molten iron is 0.31%, and the average temperature of the molten iron is as high as 1482℃.

[0063] (6) Use a tapping mode with a 5-minute interval to separate molten iron and slag for cyclic smelting operation.

[0064] Under the blast furnace smelting method of this embodiment, with an average charge grade of 56.07% and a slag ratio of 407.75 kg / t, the slag fluidity was good, but the furnace conditions fluctuated greatly. There were two instances of suspended charge and ten instances of pipework issues throughout the month. The daily qualified pig iron production was only 6649.55 t, and the utilization coefficient was 2.660 t / (m³). 3 ·d) Moreover, the coke ratio and fuel ratio are as high as 384.41 kg / t and 522.18 kg / t respectively, and the blast furnace is in an inefficient smelting state with low output and high consumption.

[0065] The smelting parameters of Examples 1-3 and Comparative Examples 1-2 of the present invention are shown in Table 1.

[0066] Table 1 As shown in Table 1, under the production conditions of low grade and high slag ratio, the comprehensive benefits of increased production, improved efficiency and energy saving were achieved, and the economy and efficiency of smelting were improved. In contrast, the blast furnace conditions of Comparative Examples 1 and 2, which did not use the method of the present invention, were prone to fluctuations and had poor production stability. The daily output and utilization coefficient were lower than those of Examples 1 and 3.

[0067] In summary, this method can promote increased blast furnace output and utilization coefficient, reduce fuel ratio and coke ratio, and achieve high-efficiency smelting with blast furnace production technical indicators reaching and exceeding the industry average level when using low-grade, high-slag-ratio ores, while ensuring good permeability index.

[0068] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A blast furnace smelting method for increasing production and reducing energy consumption under high slag ratio conditions, characterized in that, Specifically, the following steps are included: (1) Mix sinter, magnesia pellets and lump ore to obtain iron-containing raw materials, and charge coke and iron-containing raw materials into a blast furnace to obtain a mixed raw material system; (2) The mode of emptying the silo → replacing the old material → mixing the new material and the old material and feeding it into the furnace → feeding the furnace with completely new material is adopted. At the same time, heterogeneous or inferior sintered ore is supplied to the blast furnace trough. (3) Block the three tuyeres above the blast furnace taphole, and use Φ120mm tuyeres for the remaining tuyeres to ensure even air intake; (4) Adjust the pulverized coal injection ratio, differential pressure and top pressure to stabilize the furnace operation; (5) Inject oxygen-rich hot air into the blast furnace to maintain the theoretical combustion temperature; (6) The zero-interval tapping mode is adopted to separate molten iron and slag and carry out cyclic smelting operation.

2. The blast furnace smelting method for increasing production and reducing energy consumption under high slag ratio conditions according to claim 1, characterized in that, The sinter grade in step (1) is ≥54% and the drum grade is ≥79%.

3. The blast furnace smelting method for increasing production and reducing energy consumption under high slag ratio conditions according to claim 1, characterized in that, The magnesium pellets mentioned in step (1) have a grade of ≥59%, a compressive strength of ≥2000N / pellet, and an MgO content of 1.0~1.5%; the coke has a CRI ≤25%, CSR ≥67%, M40 ≥88%, and M10 ≤6%.

4. The blast furnace smelting method for increasing production and reducing energy consumption under high slag ratio conditions according to claim 1, characterized in that, In step (1), the mass percentage of sintered ore in each batch of iron-containing raw materials is 68%~74%, the mass percentage of magnesium pellets is 23%~27%, and the remainder is lump ore; the amount of coke added is 11.5~12.5t / batch.

5. The blast furnace smelting method for increasing production and reducing energy consumption under high slag ratio conditions according to claim 1, characterized in that, The magnesium-aluminum ratio in the mixed raw material system described in step (1) is 0.65~0.75, and the mass percentage of MgO in the mixed raw material system is 7.0%~9.0%.

6. The blast furnace smelting method for increasing production and reducing energy consumption under high slag ratio conditions according to claim 1, characterized in that, In step (2), the batch of ore fed into the furnace is 54-56 t / batch, and the average material rate is 9.0-9.5 batches / h; the amount of heterogeneous or inferior sintered ore fed in is ≤3 t / batch.

7. The blast furnace smelting method for increasing production and reducing energy consumption under high slag ratio conditions according to claim 1, characterized in that, The uniform air intake conditions mentioned in step (3) are: an average air volume of 4600~4700 m³ / h. 3 / min, wind speed is 240~260m / s; furnace gas volume is 6100~7100m 3 / min.

8. The blast furnace smelting method for increasing production and reducing energy consumption under high slag ratio conditions according to claim 1, characterized in that, The pulverized coal injection ratio mentioned in step (4) is 140~145 kg / t.

9. The blast furnace smelting method for increasing production and reducing energy consumption under high slag ratio conditions according to claim 1, characterized in that, The pressure difference mentioned in step (4) is the difference between the hot air pressure and the furnace top pressure. The pressure difference is ≤185Kpa, and the furnace top pressure is 0-10Kpa higher than the pressure difference.

10. The blast furnace smelting method for increasing production and reducing energy consumption under high slag ratio conditions according to claim 1, characterized in that, The oxygen enrichment rate in step (5) is 4.80% to 5.50%; the hot air temperature is 1150 to 1220°C; and the theoretical combustion temperature is 2350 to 2530°C.

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