A blast furnace burden structure and smelting process

Abstract

The present invention belongs to the technical field of blast furnace smelting, and particularly relates to a blast furnace burden structure and a smelting process. The burden structure includes (by mass percentage): 70 - 78% of high-alkali sinter, 18 - 22% of acidic sinter, and 3 - 10% of mixed lump ore. The CaO / SiO2 of the high-alkali sinter is controlled at 1.75 - 1.85; the CaO / SiO2 of the acidic sinter is controlled at 0.45 - 0.53. By adjusting the composition of the acidic sinter and designing the blast furnace burden structure, the present invention increases the proportion of sinter, makes full use of the production capacity of the sintering machine; adjusts the burden distribution matrix and the air supply parameters, optimizes the blast furnace smelting process, increases the output, stabilizes the indexes, and reduces the production cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of blast furnace smelting, and particularly relates to a blast furnace burden structure and a smelting process. Background Art

[0002] As the steel industry enters the era of meager profits, reducing the production cost of hot metal has become an important means for steel plants to make a profit. Steel enterprises usually effectively reduce the production cost of hot metal by giving full play to the production capacity of sintering machines, increasing the proportion of sinter, and reducing high-price pellet ore. In addition, in order to balance the slag-making system of the blast furnace, the binary basicity R2 of the blast furnace slag is usually controlled at 1.15 - 1.25% by increasing the proportion of sinter in the blast furnace burden, that is, adding acid sinter instead of high-price pellet ore. Acid sinter refers to sinter with an alkalinity (CaO / SiO2) lower than that of the blast furnace slag, which is sintered from iron concentrate or rich ore powder without adding or adding less flux. Acid sinter has poor metallurgical properties, low reduction degradation at low temperature, low reducibility, low drum strength. After adding acid sinter to the blast furnace burden, the production is often unstable, the fuel consumption index becomes worse, the production cost increases, and the hot metal output decreases. How to reduce the impact of acid sinter on the furnace condition and reduce the production cost is the technical problem to be solved by the present invention. Summary of the Invention

[0003] The purpose of the present invention is to provide a blast furnace burden structure and a smelting process. By adjusting the composition of acid sinter, adjusting the burden distribution matrix and the air supply parameters, the problems such as the deterioration of the fuel consumption index and the reduction of the hot metal output caused by adding acid sinter are improved, the use amount of sinter is further increased, the production capacity of the sintering machine is fully utilized, the output is increased, the indexes are stabilized, and the production cost is reduced.

[0004] The present invention provides a blast furnace burden structure, which is charged with high-alkali sinter and acid sinter. Specifically, the blast furnace burden structure includes, by mass percentage: 70 - 78% of basic sinter, 18 - 22% of acid sinter, and 3 - 10% of lump ore.

[0005] Among them, the component weight percentage of the basic sinter is: TFe 55.00 - 56.50%, S 0.01 - 0.02%, SiO2 4.5 - 6.0%, CaO 8.56 - 10.48%, MgO 2.50 - 2.90%, AL2O3 2.30 - 2.80%, and the alkalinity R2 (CaO / SiO2) is 1.75 - 1.85.

[0006] The component weight percentages of the acidic sinter are as follows: TFe 58.00 - 59.00%, S 0.003 - 0.010%, SiO2 6.00 - 6.80%, CaO 2.9 - 4.8%, MgO 1.20 - 1.50%, AL2O3 2.30 - 2.80%, and the basicity R2 (CaO / SiO2) is 0.45 - 0.53.

[0007] The component weight percentages of the lump ore are as follows: TFe 58.00 - 65.00%, S 0.010 - 0.030%, SiO2 2.5 - 6.5%, CaO 0.1 - 0.4%, MgO 0.01 - 0.065%, AL2O3 0.1 - 2.0%, and the basicity R2 (CaO / SiO2) is 0.01 - 0.1.

[0008] The present invention also provides a blast furnace smelting process for the above - mentioned blast furnace burden, which includes the following steps:

[0009] The set mass of each batch of blast furnace burden is 62 - 68t; the corresponding mass of each batch of coke is 11 - 13t;

[0010] The structural ratio of the coke, calculated by mass percentage, includes: primary coke 20 - 30%, coke dry quenched 70 - 80%; the component requirements of the prepared coke are as follows:

[0011] 。

[0012] There are a total of 10 burden bins under the blast furnace, namely bin No. 1, bin No. 2, bin No. 3, bin No. 4, bin No. 5, bin No. 6, bin No. 7, bin No. 8, bin No. 9, and bin No. 10.

[0013] There are 4 coke bins under the blast furnace, namely bin C1, bin C2, bin C3, and bin C4.

[0014] Step 1: The basic sinter is evenly loaded into bins No. 1 - 6; the acidic sinter is evenly loaded into bins No. 9 and No. 10; the lump ore is evenly loaded into bins No. 7 and No. 8. The primary coke is loaded into bin C1 and bin C4; the coke dry quenched is loaded into bin C2 and bin C3.

[0015] Step 2: When the stock bins are all filled and the bin level > 5m, start discharging materials. When discharging, first discharge the basic sinter ore from the 6#, 5#, and 4# basic sinter ore bins in sequence. The discharging interval between the 6#, 5#, and 4# bins is 5 seconds. After the discharging of the 6#, 5#, and 4# bins is completed in sequence, with an interval of 8 seconds, start discharging the acid sinter ore from the 10# and 9# bins. The discharging interval between the 10# and 9# bins is 5 seconds. After the discharging of the 10# and 9# bins is completed, with an interval of 8 seconds, start discharging the lump ore from the 7# and 8# bins. The 7# and 8# bins discharge materials in sequence, with a discharging interval of 5 seconds; after the discharging of the 7# and 8# bins is completed, with an interval of 8 seconds, discharge the basic sinter ore from the 3#, 2#, and 1# bins. The 3#, 2#, and 1# bins discharge materials at intervals of 5 seconds in sequence.

[0016] Step 3: Discharge the furnace materials on the conveyor belt into the BF tundish in sequence.

[0017] Step 4: Adjust the chute feeding angle, which is divided into 41.5 ± 0.5°, 39.5 ± 0.5°, 37.5 ± 0.5°, 35.5 ± 0.5°, and 33.5 ± 0.5°.

[0018] Step 5: When the chute feeding angle is 41.5 ± 0.5°, feed the ore batch for 2 circles; then adjust the chute feeding angle to 39.5 ± 0.5° and feed for 3 circles; then adjust the chute feeding angle to 37.5 ± 0.5° and feed for 3 circles; then adjust the chute feeding angle to 35.5 ± 0.5° and feed for 3 circles; finally, adjust the chute feeding angle to 33.5 ± 0.5° and feed for 2 circles until all the materials are fed.

[0019] Step 6: After all the furnace materials are fed, with an interval of 10 seconds, discharge the first-grade coke from the C4 coke bin. Stop discharging when the set target weight is reached. With an interval of 5 seconds, discharge the coke cooled by dry quenching from the C3 coke bin. Stop discharging when the set target weight is reached. Similarly, discharge from the C2 and C1 coke bins in sequence.

[0020] Step 7: Discharge the coke on the conveyor belt into the BF tundish in sequence.

[0021] Step 8: Adjust the chute feeding angle, which is divided into 42 ± 0.5°, 40 ± 0.5°, 37.5 ± 0.5°, 35 ± 0.5°, 32 ± 0.5°, and 29 ± 0.5°.

[0022] Step 9: When the chute feeding angle is 42 ± 0.5°, feed the coke batch for 2 circles; then adjust the chute feeding angle to 40 ± 0.5° and feed for 2 circles; then adjust the chute angle to 37.5 ± 0.5° and feed for 2 circles; then adjust the chute feeding angle to 35 ± 0.5° and feed for 2 circles; then adjust the chute feeding angle to 32 ± 0.5° and feed for 2 circles; finally, adjust the chute feeding angle to 29 ± 0.5° and feed for 2 circles until all the materials are fed.

[0023] Step Ten: After all the burden materials and coke are charged, increase the oxygen enrichment rate in the blast parameters by 1-3%, and stabilize the blast volume at 3800-3850 m 3 / min.

[0024] The innovation points of the present invention are as follows:

[0025] 1. We optimize the discharging sequence and adjust the charging angle of the poor metallurgical performance acid sinter ore, surround the acid sinter ore with the good metallurgical performance basic sinter ore, and at the same time precisely limit the acid sinter ore in the middle annulus area with the least influence on blast furnace smelting, minimizing the impact of the acid sinter ore on smelting.

[0026] 2. We adjust the charging angle of the ore zone in the blast furnace, adjust the innermost angle to 33.5° and the outermost angle to 41.5°, shrink the entire blast furnace charging cross-sectional area into an 8° ore zone, dredge the central and edge coal gas flows, make the blast furnace smelting more stable, and integrate the influence of the acid sinter ore on the coal gas flow.

[0027] 3. We optimize the smelting process, utilize its 94% high clinker ratio and 22.4 high gas permeability, increase the dosage of low-cost dry coke by 10%, reduce the dosage of expensive primary coke by 10%, and reduce the manufacturing cost per ton of iron.

[0028] 4. We increase the oxygen enrichment rate by 1-3%, stabilize the blast volume at 3800-3850 m 3 / min, stabilize the blast furnace belly gas volume index, utilize the high gas and liquid permeability of this smelting process, at the same time make the high-temperature zone move downward, increase the middle-temperature zone interval, increase the indirect reaction interval of the burden materials, and improve the gas utilization rate to reduce energy consumption and increase production.

[0029] 5. Through these adjustments, we can significantly increase the proportion of acid sinter, make full use of the production capacity of the sintering machine. At the same time, the acid sinter replaces the expensive pellets, reducing the material cost per ton of iron. Also, due to the increase in the oxygen enrichment rate combined with the use of acid sinter, the output of blast furnace hot metal not only does not decrease, but also increases to a certain extent. Specific Embodiments

[0030] The following is a further detailed description in combination with specific embodiments: Embodiment 1

[0031] A blast furnace burden structure and smelting process with high basicity sinter ore and acid sinter ore added:

[0032] The burden structure includes (by mass percentage): ore batch of 62t, high basicity sinter of 75%, weight 46.5t, basicity R2 (CaO / SiO2) control range: 1.82; acid sinter of 19%, weight 11.78t, basicity R2 (CaO / SiO2) control range: 0.5; mixed lump ore of 6%, weight 3.72t. Coke batch of 11.71t, primary coke of 30%, weight 3.513t; coke dry quenching of 70%, weight 8.197t.

[0033] The compositions of basic sinter, acid sinter and lump ore are as follows:

[0034]

[0035] The composition of coke is as follows:

[0036] .

[0037] The smelting process is as follows:

[0038] The burden batch weight is 62t, the mass of basic sinter accounts for 75%: 46.5t; the mass of acid sinter accounts for 19%: 11.78t; the mass of lump ore accounts for 6%: 3.72t.

[0039] The coke batch weight is 11.71t, primary coke of 30%, weight 3.513t; coke dry quenching of 70%, weight 8.197t.

[0040] There are a total of 10 bunkers in the BF trough bunker, namely Bunker No. 1, Bunker No. 2, Bunker No. 3, Bunker No. 4, Bunker No. 5, Bunker No. 6, Bunker No. 7, Bunker No. 8, Bunker No. 9, and Bunker No. 10.

[0041] There are 4 coke bunkers in the BF trough, namely Bunker C1, Bunker C2, Bunker C3, and Bunker C4.

[0042] Step 1: 46.5t of basic sinter is evenly loaded into Bunkers No. 1 - 6, 7.75t for each bunker; 11.78t of acid sinter is evenly loaded into Bunkers No. 9 and 10, 5.89t for each bunker; 3.72t of lump ore is evenly loaded into Bunkers No. 7 and 8. 3.513t of primary coke is evenly loaded into Bunkers C1 and C4; 8.197t of coke dry quenching is evenly loaded into Bunkers C2 and C3.

[0043] Step 2: When the stock bins are all filled and the bin level > 5m, start discharging materials. When discharging, first discharge the basic sinter ore from the 6#, 5#, and 4# basic sinter ore bins in sequence. The discharging interval between the 6#, 5#, and 4# bins is 5 seconds. After the discharging of the 6#, 5#, and 4# bins is completed in sequence, with an interval of 8 seconds, start discharging the acid sinter ore from the 10# and 9# bins. The discharging interval between the 10# and 9# bins is 5 seconds. After the discharging of the 10# and 9# bins is completed with an interval of 8 seconds, start discharging the lump ore from the 7# and 8# bins. The 7# and 8# bins discharge materials in sequence, with a discharging interval of 5 seconds; after the discharging of the 7# and 8# bins is completed with an interval of 8 seconds, discharge the basic sinter ore from the 3#, 2#, and 1# bins. The 3#, 2#, and 1# bins discharge materials at intervals of 5 seconds in sequence.

[0044] Step 3: Discharge the furnace materials on the belt into the BF tundish in sequence.

[0045] Step 4: Adjust the chute feeding angle, which is divided into 41.5°, 39.5°, 37.5°, 35.5°, and 33.5°.

[0046] Step 5: When the chute is at 41.5°, distribute the furnace materials in the tundish in sequence for 2 laps; then adjust the chute feeding angle to 39.5° and distribute for 3 laps; then adjust the chute angle to 37.5° and distribute for 3 laps; then adjust the chute angle to 35.5° and distribute for 3 laps; finally, adjust the chute angle to 33.5° and distribute for 2 laps, and all the furnace materials are distributed.

[0047] Step 6: After all the furnace materials are distributed, with an interval of 10 seconds, discharge the primary coke from the C4 coke bin. Stop discharging after reaching the set target weight. With an interval of 5 seconds, discharge the coke for dry quenching from the C3 coke bin. Stop discharging after reaching the set target weight. Similarly, discharge from the C2 and C1 coke bins in sequence.

[0048] Step 7: Discharge 11.78t of coke on the belt into the BF tundish in sequence.

[0049] Step 8: Adjust the chute feeding angle, which is divided into 42°, 40°, 37.5°, 35°, 32°, and 29°.

[0050] Step 9: When the chute is at 42°, distribute the coke discharged into the tundish in sequence for 2 laps; then adjust the chute feeding angle to 40° and distribute for 2 laps; then adjust the chute angle to 37.5° and distribute for 2 laps; then adjust the chute angle to 35° and distribute for 2 laps; then adjust the chute angle to 32° and distribute for 2 laps; finally, adjust the chute angle to 29° and distribute for 2 laps, and all the coke is distributed.

[0051] Step 10: After all the furnace materials and coke are distributed, increase the oxygen enrichment rate of the air supply parameter by 1.03%, that is, increase the oxygen enrichment by 3000m 3 / h; the air volume is 3830m 3 / min. Comparative Example 1

[0052] The production process of No. 8 blast furnace in the Special Steel Ironmaking Plant of Zhongtian Iron and Steel Co., Ltd. originally:

[0053] The mass of a batch of furnace burden is 62t. The mass of basic sinter accounts for 80%: 49.6t; the mass of pellet (Nantong pellet) accounts for 12%: 7.44t; the mass of lump ore accounts for 8%: 4.96t.

[0054] The corresponding mass of coke is 12.72t, the mass of first-class coke accounts for 40%: 5.088t, and the mass of dry quenched coke accounts for 60%: 7.632t.

[0055] The components are as follows:

[0056]

[0057] The components of coke are as follows:

[0058] .

[0059] Step 1: 49.6t of basic sinter is evenly loaded into bins 1# - 6#, with 8.26t in each bin; 7.44t of Nantong pellets is evenly loaded into bins 9# and 10#, with 3.72t in each bin; 4.96t of FMG is evenly loaded into bins 7# and 8#. 5.088t of first-class coke is evenly loaded into bin C1 and bin C2; 7.632t of dry quenched coke is evenly loaded into bin C3 and bin C4.

[0060] Step 2: When the stock bins are all prepared and the bin level > 5m, start discharging. The bins discharge in the order of 1# - 10#, with a 5-second interval between bins.

[0061] Step 3: Discharge the furnace burden on the conveyor belt into the blast furnace tundish in sequence.

[0062] Step 4: Adjust the chute distribution angle to 39°, 37°, 35°, 33°, 30.5°.

[0063] Step 5: When the furnace burden distributed in sequence in the tundish is at a chute angle of 39°, charge for 2 circles; then adjust the chute angle to 37° and charge for 3 circles; then adjust the chute angle to 35° and charge for 3 circles; then adjust the chute angle to 33° and charge for 3 circles; finally, adjust the chute angle to 30.5° and charge for 2 circles until all the furnace burden is charged.

[0064] Step 6: After all the furnace burden is charged, wait for 10 seconds and then start discharging coke. The coke bins discharge in sequence from C1 - C4, with a 5-second interval between bins.

[0065] Step 7: Discharge 12.72t of coke on the conveyor belt into the blast furnace tundish in sequence.

[0066] Step Eight: Adjust the chute feeding angle to 40°, 38°, 35.5°, 33°, 30°, and 27°.

[0067] Step Nine: Discharge the coke into the intermediate ladle in sequence and feed it for 2 laps at a chute angle of 40°; then adjust the chute angle to 38° and feed for 2 laps; then adjust the chute angle to 35.5° and feed for 2 laps; then adjust the chute angle to 33° and feed for 2 laps; then adjust the chute angle to 30° and feed for 2 laps; finally, adjust the chute angle to 27° and feed for 2 laps until all the coke is fed.

[0068] Step Ten: After all the burden and coke are fed, the oxygen enrichment rate of the air supply parameter is 3.39%, and the air volume is 3830 m 3 / min.

[0069] Table 1 Calculation of Blast Furnace Smelting Cost and Output

[0070] .

[0071] As can be seen from Table 1, using the burden structure and smelting process of the present invention, the cost per ton of iron (materials + coke) is 2321.2, and the cost reduction is 2321.2 - 2368 = 46.8 yuan / t. Using the smelting process of the present invention, the theoretical output increase is approximately (1.03%) / 1% * 4.76% * 3800 = 186.3 t.

[0072] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and concept of the present invention, makes equivalent substitutions or changes, and should be covered within the protection scope of the present invention. The present invention is not limited to the following specific embodiments. Those of ordinary skill in the art can implement the present invention in other various specific embodiments according to the content disclosed by the present invention, or any simple changes or modifications made by adopting the design structure and idea of the present invention fall within the protection scope of the present invention. It should be noted that, without conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

Claims

1. A blast furnace smelting process, characterized in that, The burden per batch of the blast furnace is 62 - 68t. The burden structure of the blast furnace burden includes, by mass percentage: 70 - 78% of basic sinter, 18 - 22% of acid sinter, and 3 - 10% of lump ore; the basicity of the basic sinter is 1.75 - 1.85, the basicity of the acid sinter is 0.45 - 0.53, and the basicity of the lump ore is 0.01 - 0.1; the coke burden per batch is 11 - 13t; There are a total of 10 bins for the blast furnace burden under the blast furnace trough, namely Bin No. 1, Bin No. 2, Bin No. 3, Bin No. 4, Bin No. 5, Bin No. 6, Bin No. 7, Bin No. 8, Bin No. 9, and Bin No. 10; There are 4 coke bins under the blast furnace trough, namely Bin C1, Bin C2, Bin C3, and Bin C4; Step 1: Evenly load the basic sinter into Bins No. 1 - 6; evenly load the acid sinter into Bins No. 9 and No. 10; evenly load the lump ore into Bins No. 7 and No. 8; load the first - grade coke into Bins C1 and C4; load the dry - quenched coke into Bins C2 and C3; Step 2: When the stock bins are all prepared and the bin level > 5m, start discharging. When discharging, first discharge the basic sinter in Bins No. 6, No. 5, and No. 4 in sequence. The discharging intervals of Bins No. 6, No. 5, and No. 4 are 5 seconds. After the discharging of Bins No. 6, No. 5, and No. 4 is completed in sequence, with an interval of 8 seconds, start discharging the acid sinter in Bins No. 10 and No.

9. The discharging intervals of Bins No. 10 and No. 9 are 5 seconds. After the discharging of Bins No. 10 and No. 9 is completed with an interval of 8 seconds, start discharging the lump ore in Bins No. 7 and No.

8. Bins No. 7 and No. 8 discharge in sequence with a discharging interval of 5 seconds; after the discharging of Bins No. 7 and No. 8 is completed with an interval of 8 seconds, discharge the basic sinter in Bins No. 3, No. 2, and No.

1. Bins No. 3, No. 2, and No. 1 discharge at intervals of 5 seconds in sequence; Step 3: Discharge the blast furnace burden on the belt into the blast furnace intermediate ladle in sequence; Step 4: Adjust the chute distribution angle to 41 - 42°, 39 - 40°, 37 - 38°, 35 - 36°, 33 - 34°; Step 5: When the chute distribution angle is 41 - 42°, distribute the burden for 2 circles; then adjust the chute distribution angle to 39 - 40° and distribute the burden for 3 circles; then adjust the chute distribution angle to 37 - 38° and distribute the burden for 3 circles; then adjust the chute distribution angle to 35 - 36° and distribute the burden for 3 circles; finally, adjust the chute distribution angle to 33 - 34° and distribute the burden for 2 circles, and all the blast furnace burden is distributed; Step 6: After all the blast furnace burden is distributed, with an interval of 10 seconds, Bin C4 discharges. When the set target weight is reached, stop discharging. With an interval of 5 seconds, Bin C3 discharges. When the set target weight is reached, stop discharging. Similarly, discharge Bins C2 and C1 in sequence; Step 9: Discharge the coke on the belt into the blast furnace intermediate ladle in sequence; Step 10: Adjust the chute distribution angle to 41.5 - 42.5°, 39.5 - 40.5°, 37 - 38°, 34.5 - 35.5°, 31.5 - 32.5°, 28.5 - 29.5°; Step 9: When the chute feeding angle is 41.5 - 42.5°, feed the coke in batches for 2 laps; then adjust the chute feeding angle to 39.5 - 40.5° and feed for 2 laps; then adjust the chute feeding angle to 37 - 38° and feed for 2 laps; then adjust the chute feeding angle to 34.5 - 35.5° and feed for 2 laps; then adjust the chute feeding angle to 31.5 - 32.5° and feed for 2 laps; finally, adjust the chute feeding angle to 28.5 - 29.5° and feed for 2 laps until all the coke is fed. Step Ten: After all the burden materials and coke in the blast furnace are charged, increase the oxygen enrichment rate of the blast parameters by 1-3% and stabilize the blast volume at 3800-3850 m 3 / min.

2. The blast furnace smelting process according to claim 1, characterized in that, The coke structure includes, by mass percentage: 20 - 30% of first-class coke and 70 - 80% of dry quenched coke.

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