Economical charging method for blast furnace smelting
By using ordinary firewood to fill the hearth in blast furnace smelting, controlling the grade and particle size of the feed material, adjusting the composition of coke and slag, and optimizing operating parameters, the problems of high cost and poor start-up smoothness in blast furnace smelting were solved, and efficient start-up of economical feed material was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-04-26
- Publication Date
- 2026-04-10
AI Technical Summary
In existing blast furnace smelting, the use of high-quality raw materials and fuels leads to high costs and is prone to problems such as poor slag fluidity and insufficient heat, which affect the smoothness of furnace start-up. At present, the potential for cost reduction is limited.
The furnace hearth is filled with ordinary firewood. The grade and particle size of the feed material are controlled, the composition of coke and slag is adjusted, and the start-up operation parameters are optimized to ensure air permeability and smooth slag and iron discharge. Costs are reduced through refined operation.
While ensuring smooth start-up and rapid production, the start-up cost was reduced, and the efficient use of economical furnace materials was achieved.
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of steel smelting, and particularly relates to an economic burden starting method for blast furnace smelting. BACKGROUND
[0002] At present, the relatively best raw fuel and auxiliary fuel in the resource condition range is often used for blast furnace starting, the quality of the raw fuel is improved, and the blast furnace slag ratio is reduced to ensure the smooth starting of the blast furnace and the rapid reaching of the production and efficiency. Although this can create good conditions for the smooth starting of the blast furnace to a certain extent, the use of a large amount of fine material often leads to a large amount of cost investment, which is not conducive to the development of cost reduction and efficiency improvement work. At the same time, if the quality of the raw material is too good and the slag ratio is too low, the slag (Al2O3) is prone to be too high, the slag flowability is poor, and the heat of the hearth is not sufficient, which brings adverse effects on the smooth starting of the blast furnace. In addition, the current steel industry is in a difficult situation, and the cost pressure is huge. The cost reduction work has penetrated into all aspects of blast furnace smelting. Under the condition that the starting technology is continuously mature, the difficulties encountered during the starting period can be responded in advance, and the rapid reaching of the production and efficiency can be fully guaranteed, the quality of the starting raw fuel is appropriately reduced, the cost of the starting raw fuel is reduced, the advantages of economic burden starting are further explored, and the cost reduction work of economic burden starting has important technical significance under the condition that the current cost reduction potential is very limited. SUMMARY
[0003] The purpose of the present application is to provide an economic burden starting method for blast furnace smelting.
[0004] The purpose of the present application is achieved in that an economic burden starting method for blast furnace smelting is achieved in the following steps:
[0005] 1) wood is filled into the hearth below the tuyere, when the wood is filled to the lower edge of the tuyere, the wood is vertically placed on the circumference of the tuyere to protect the small sleeve in the tuyere, and then the charging is performed according to the charging requirements;
[0006] 2) the normal burden grade control is 56.5-57%, the coke CSR is controlled to be greater than or equal to 68.00%, the M40 is controlled to be greater than or equal to 88.00%, the M10 is controlled to be less than or equal to 6.0%, the Zn load is controlled to be less than or equal to 0.5 kg / t, and the alkali load is controlled to be less than or equal to 3.5 kg / t;
[0007] 3) the total furnace coke ratio is controlled to be 2.60-2.70, the dolomite addition amount is 110 t, the silica addition amount is 60 t, the total furnace slag ratio is 700-800 kg / t, the normal burden alkali degree is controlled to be 0.95-1.0 times, the total furnace alkali degree is 0.70-0.80, and it is ensured that (MgO) in the slag is greater than or equal to 8.0%, (Al2O3) is less than or equal to 13%, and (TiO2) is less than or equal to 4.0%;
[0008] 4) Before ignition, bury the oxygen lance into place at two tuyeres, and leave one tuyere as the iron injection tuyere during the air blast period;
[0009] 5) The number of tuyeres opened at the initial stage of blowing is 50-60% of the total number of tuyeres, and the pressure difference is controlled at the initial stage of blowing of the blast furnace, and the pressure difference is controlled at 70-80% of the normal pressure difference, and the air volume entering the furnace is 1.0-1.2 times the furnace capacity.
[0010] To improve the economy of blowing, it is necessary to ensure the strength index of raw fuel and auxiliary materials, the particle size index, and the metallurgical performance index as the basic premise, and to ensure the smooth blowing by optimizing the details of the blowing calculation and creating smooth iron conditions. The method of the present application can ensure the permeability of the blast furnace by ensuring the cold and hot strength index of the coke and the use of full dry quenching, which lays a good foundation for the smooth blowing of the blast furnace; by ensuring that the particle size index and the metallurgical performance of the raw materials entering the furnace meet the production requirements, the harmful element load of Zn, Ti and alkali metals is strictly controlled according to the boundary of the blast furnace production requirements, which creates good conditions for the smooth blowing; by doing a good job in the calculation of blowing, the ore coke load, slag ratio, basicity and slag composition are precisely selected and controlled, which can ensure sufficient furnace temperature and create conditions for smooth discharge of slag and iron; finally, by strengthening the operation control, fully preparing for the blowing, ensuring the scientific and orderly development of the blowing, such as oven, charging, burying oxygen lance, and strengthening the fine operation of the blowing process, the smooth blowing is ensured.
[0011] The economic burden method of the blast furnace smelting provided by the present application can reduce the cost of blowing while ensuring smooth blowing and rapid production. DETAILED DESCRIPTION
[0012] The present application will be further described below in conjunction with examples, but in no way limits the present application, any transformation or replacement based on the teaching of the present application belongs to the protection scope of the present application.
[0013] The economic burden method of the blast furnace smelting provided by the present application can reduce the cost of blowing while ensuring smooth blowing and rapid production.
[0014] 1) Fill the area below the tuyere center line with ordinary wood instead of sleepers, and fill the wood into the tuyere below the tuyere, and when the wood is filled to the tuyere, the wood is placed vertically around the tuyere;
[0015] 2) Normal sintered ore sintering: pellet: lump ore ratio of 65%:25%:10% (lump ore ratio is controlled within 10%, and the sinter and pellet ratio is based on the target of blast furnace slag basicity. The comprehensive grade into the furnace is 56.5-57; the sinter grade is controlled above 54.5%, among which, the imported ore ratio in the mixed ore stacking ratio is 25%-35%, the other purchased ore ratio is 58%-68%, and the dolomite ratio is 7%, the dust addition is temporarily stopped, the sinter basicity is 2.10-2.35, the drum index reaches more than 80%, and the powder into the furnace is less; the pellet grade is controlled at about 61%, the vanadium-titanium concentrate is stopped, and the daily balling concentrate with single variety is used for pellet production, the pellet normal temperature compression strength is ≥2000N / individual ball, and the expansion rate is ≤20.00%; the old Laotian lump ore with high cost performance, stable quality, grade greater than 65% and qualified particle size index is selected;
[0016] 3) The coke used in daily production is coke, and the coke is dry quenched, the coke CSR is ≥68.00%, the M40 is ≥88.00%, the M10 is ≤6.0%, the total furnace coke ratio is controlled to be 2.60 times, and the daily quality stable spraying coal is used;
[0017] 4) No manganese ore is used in the initial stage of the blast furnace, the total furnace coke ratio is controlled to be 2.60-2.70, the dolomite and silica are used to adjust the slag basicity, the total furnace slag ratio is 700-800 kg / t, the total furnace basicity is 0.70-0.80, the total furnace slag ratio is 700-800 kg / t, the normal material basicity is controlled to be 0.95-1.0 times, the total furnace basicity is 0.70-0.80, the slag in the blast furnace is ensured to be (MgO) ≥8.0%, (Al2O3) ≤13%, and (TiO2) ≤4.0%;
[0018] 5) The number of blast furnace tuyere is increased, the tuyere number in the initial stage of the blast furnace accounts for 50-60% of the total tuyere, the blast furnace is controlled in the initial stage of the blast furnace, the corresponding relationship between the air volume and the air pressure is controlled, the pressure difference is controlled to be 70-80% of the normal pressure difference, and the air volume into the furnace is 1.0-1.2 times of the furnace capacity.
[0019] The following takes Kunming Steel 2500m 3 Blast Furnace as an example to further illustrate the present application.
[0020] Example 1
[0021] 1. Prepare enough wood, coke, pulverized coal, sinter, pellet, lump ore and flux in advance for filling the hearth, and detect and monitor the composition, quality and metallurgical properties, with coke CSR≥68.00%, M40≥88.00%, M10≤6.0%, control the particle size and metallurgical properties of the ore to meet the production requirements of the blast furnace, control the Zn load≤0.5kg / t and the alkali load≤3.5kg / t; the comprehensive grade control is 57%, among which the sinter: pellet: lump ore ratio is 65:25:10. The sinter grade is 54.5%, among which the mixed ore stacking ratio is 30% for imported ore, 63% for other purchased ore, and 7% for dolomite, and the sintering dust is temporarily suspended, the sintering alkali is 2.25 times, the drum index is 80%, and the powder into the furnace is small; the pellet grade is 61%, the vanadium-titanium concentrate is stopped, and the daily balling concentrate with single variety is used for pellet production, the pellet normal temperature compression strength is 2500N / each, and the expansion rate is 15-20%; the old Laos lump ore with high selectivity, stable quality and grade of about 66% and qualified particle size index is selected;
[0022] 2. Control the total coke ratio to 2.68, do not use manganese ore at the start of the blast, use dolomite and silica to adjust the slag basicity, the dolomite addition amount is 110t, the silica addition amount is 60t, the total slag ratio is 750kg / t, the total basicity is 0.75, the slag (MgO):8.30%, (Al2O3):12.85%, (TiO2):2.75%;
[0023] 3. Fill wood into the hearth below the tuyere, when the wood is filled to the lower edge of the tuyere, stand the wood vertically around the tuyere to protect the small sleeve in the tuyere, and then load according to the loading requirements;
[0024] 4. Before ignition, bury the oxygen lance in place at two iron mouths, and leave one iron mouth for iron injection during the reblowing period;
[0025] 5. Complete the preparation confirmation work before ignition, reasonably control the start-up operation parameters, increase the number of tuyeres blocked during start-up, and open 16 tuyeres (accounting for 53% of the total tuyeres) during the initial stage of the start-up of the blast furnace, control the pressure difference during the initial stage of the start-up of the blast furnace, the inlet air volume is 2700m 3 / min, and the pressure difference is 150kPa;
[0026] 6. Pay attention to the iron injection situation and the work situation of the oxygen lance buried in the hearth, and orderly organize the intensified smelting and iron tapping arrangement according to the furnace condition parameters, open the iron mouth to tap the first iron 11 hours after reblowing, and the interval time of early iron tapping is 2 hours.
[0027] 7. After the re-airing, the ore and coke load increases from 2.31 to 2.62 in 13 hours, to 2.93 in 24 hours, to 3.70 in 30 hours, to 4.00 in 40 hours, and to 4.26 in 48 hours, gradually reducing the silicon content of molten iron to about 1%.
[0028] This furnace start-up method can achieve the goals of tapping iron in 11 hours, injecting pulverized coal in 36 hours, reducing the silicon content of molten iron to about 1% in two days, rapidly increasing the number of working tuyeres, and reaching full production capacity in three days. Based on the cost calculation during the 10-day start-up period, it can reduce costs by more than 20 million yuan.
[0029] Example 2
[0030] 1. Prepare sufficient quantities of firewood, coke, pulverized coal, sinter, pellets, lump ore, and flux for hearth filling in advance. Conduct component quality and metallurgical performance testing and monitoring. The coke CSR should be ≥68.00%, M40 ≥88.00%, and M10 ≤6.0%. Control the ore particle size and metallurgical performance to meet the blast furnace production requirements. Control the Zn load to the furnace to ≤0.5kg / t and the alkali load to ≤3.5kg / t. The overall grade of the furnace feed should be controlled at 56.8%, with the sinter: pellets: lump ore ratio being 68:24:8. The sinter grade is 54.8%, of which the blending ratio is 25% imported ore, 68% other purchased ore, and 7% dolomite. Dust removal ash is suspended. The basicity of the sinter is 2.20 times, the drum index is 82%, and the amount of powder entering the furnace is low. The pellet grade is 61%. Vanadium and titanium concentrate addition is stopped. Single-variety daily pelletizing concentrate is used for pellet production. The room temperature compressive strength of the pellets is 2400N / piece, and the expansion rate is 15-20%. For lump ore, Lao lump ore with high cost performance, stable quality, grade of about 66%, and qualified particle size is selected.
[0031] 2. Control the overall coke ratio of the furnace to 2.6. Do not use manganese ore during furnace start-up. Use dolomite and silica to adjust the slag basicity. The amount of dolomite added is 140t, the amount of silica added is 60t, the overall slag ratio is 800kg / t, the overall furnace basicity is 0.80, and the slag composition is (MgO): 8.0%, (Al2O3): 12.00%, (TiO2): 2.70%.
[0032] 3. Fill the hearth below the tuyere with firewood. When the firewood reaches the lower edge of the tuyere, place the firewood upright around the tuyere to protect the small sleeve in the tuyere. Then, load the firewood according to the loading requirements.
[0033] 4. Before ignition, bury the oxygen lance in place at both iron inlets. During the re-ventilation period, leave one iron inlet open for spraying iron.
[0034] 5. Complete the preparation confirmation work before ignition, reasonably control the start-up operation parameters, increase the number of start-up tuyere plugging, open 15 tuyeres (accounting for 50% of the total tuyeres) at the initial stage of the start-up of the blast furnace, control the pressure difference at the initial stage of the start-up of the blast furnace, the blast furnace inlet air volume is 2500m 3 / min, the pressure difference is 145kPa;
[0035] 6. Pay attention to the iron notch situation and the working condition of the furnace hearth burying the oxygen lance, orderly organize the intensified smelting and iron tapping arrangement combined with the furnace condition parameter situation, open the iron notch to tap the first iron 11 hours after the air blowing is turned on, the early iron tapping interval is 2 hours.
[0036] 7. The ore-coke burden is increased from 2.31 to 2.62 13 hours after the air blowing is turned on, to 2.93 24 hours after the air blowing is turned on, to 3.70 30 hours after the air blowing is turned on, to 4.00 40 hours after the air blowing is turned on, to 4.26 48 hours after the air blowing is turned on, and the silicon content in the molten iron is gradually reduced to about 1%.
[0037] Compared with example 1, in example 2, due to the decrease of the proportion of lump ore, the blast furnace inlet grade is reduced, the blast furnace start-up is slightly affected, after the proportion of imported ore in the sinter is reduced, the sinter machine utilization coefficient will be reduced, the consumption will be increased, the blast furnace coke ratio will be reduced, the blast furnace start-up difficulty will be increased, by reducing the number of tuyeres used in the start-up, the blast furnace coke ratio is reduced, the slag ratio is increased by increasing the flux, and the slag basicity is increased, which is helpful for diluting the slag (Al2O3) content, and is helpful for the smooth start-up of the blast furnace, and can further reduce the start-up cost.
[0038] Example 3
[0039] 1. Prepare enough wood, coke, pulverized coal, sinter, pellet, lump ore and flux for the furnace hearth filling in advance, and do a good job in the detection and monitoring of the composition quality and metallurgical performance, the coke CSR≥68.00%, M40≥88.00%, M10≤6.0%, control the ore particle size and metallurgical performance to meet the production requirements of the blast furnace, control the Zn load≤0.5kg / t and the alkali load≤3.5kg / t, the comprehensive inlet grade is controlled to be 56.6%, among which, the sinter: pellet: lump ore ratio is 70:24:6, the sinter grade is 54.7%, among which, the imported ore accounts for 20% in the mixed ore stacking ratio, other purchased ore accounts for 58%, and dolomite accounts for 7%, the dust ash is temporarily not added, the sinter basicity is 2.20 times, the drum index is 83%, and the inlet powder is small; the pellet grade is 61%, the vanadium-titanium concentrate is stopped, the daily balling concentrate with a single variety is used for pellet production, the pellet normal temperature compression strength is 2400N / individual, and the expansion rate is 15-20%; the old Laos lump ore with high selectivity, stable quality, grade of about 66% and qualified particle size index is selected;
[0040] 2. Control the total furnace coke ratio to 2.7, do not use manganese ore for blowing, use dolomite and silica to adjust the slag basicity, the addition amount of dolomite is 90t, the addition amount of silica is 60t, the total furnace slag ratio is 700kg / t, the total furnace basicity is 0.70, the slag (MgO): 8.6%, (Al2O3): 13.10%, (TiO2): 3.2%;
[0041] 3. Fill wood into the hearth below the tuyere, when the wood is filled to the lower edge of the tuyere, stand the wood vertically around the tuyere to protect the small sleeve in the tuyere, and then load according to the loading requirements;
[0042] 4. Before ignition, bury the oxygen lance in place at two iron taps, and leave one iron tap for iron injection during the blowing period;
[0043] 5. Complete the preparation confirmation work before ignition, reasonably control the blowing operation parameters, increase the number of tuyere plugging during blowing, and open 17 tuyeres (accounting for 57% of the total tuyeres) at the initial stage of blowing. The blast furnace is blown at the initial stage of blowing, the pressure difference is controlled, the air volume is 2900m 3 / min, and the pressure difference is 155kPa;
[0044] 6. Pay attention to the iron injection situation and the work situation of burying the oxygen lance in the hearth, and orderly organize the intensified smelting and iron tapping arrangement combined with the furnace condition parameters, open the iron tap to tap the first iron 11 hours after blowing, and the interval time of early iron tapping is 2 hours.
[0045] 7. The ore-coke burden is increased from 2.31 to 2.62 13 hours after blowing, to 2.93 24 hours after blowing, to 3.70 30 hours after blowing, to 4.00 40 hours after blowing, to 4.26 48 hours after blowing, and gradually reduce the silicon content in the molten iron to about 1%.
Claims
1. An economic burden start-up method for blast furnace smelting, characterized by, The following steps are implemented: 1) Use ordinary wood instead of sleepers, fill the wood into the hearth below the tuyere, when the wood is filled to the tuyere, stand the wood vertically around the tuyere to protect the small sleeve in the tuyere, then load according to the loading requirements; 2) Control the coke CSR≥68.00%, M40≥88.00%, M10≤6.0%, control the Zn load into the furnace≤0.5kg / t, the alkali load≤3.5kg / t; the comprehensive grade control into the furnace is 57%, among which, the sinter: pellet: lump ore ratio is 65:25:10, the sinter grade is 54.5%, among which, the mixed ore stacking ratio is 30% for imported ore, 63% for other purchased ore, and 7% for dolomite, the dust removal is suspended, the sinter alkalinity is 2.25 times, the drum index is 80%, the powder into the furnace is less; the pellet grade is 61%, the vanadium-titanium concentrate is stopped, the daily balling concentrate with single variety is used for pellet production, the pellet normal temperature compression strength is 2500N / individual, the expansion rate is 15~20%; the lump ore selects the old Laos lump ore with a grade of 66% and a size index that meets the requirements; 3) Control the total furnace coke ratio to be 2.68, do not use manganese ore for starting the furnace, the dolomite addition amount is 110t, the silica stone addition amount is 60t, the total furnace slag ratio is 750kg / t, the normal material alkalinity is controlled at 0.95~1.0 times, the total furnace alkalinity is 0.75, the MgO in the slag is 8.3%, the Al2O3 is 12.85%, and the TiO2 is 2.75%; 4) Before ignition, bury the oxygen lance into the position at two tap holes, and leave one tap hole as a iron injection hole during the air recovery period; 5) The number of tuyeres at the initial stage of blowing was 53% of the total number of tuyeres. The pressure difference was controlled at the initial stage of blowing of the blast furnace. The blast volume was 2700 m / min, and the pressure difference was 150 kPa. 3 / min, and the pressure difference was 150 kPa.
2. The economic burden start-up method for blast furnace smelting according to claim 1, characterized in that, In step 2), the coke is daily production coke and / or full dry quenching coke.