CN111705176B - Method for discharging slag iron by using oxygen lance during blow-in of blast furnace and oxygen lance thereof - Google Patents
Method for discharging slag iron by using oxygen lance during blow-in of blast furnace and oxygen lance thereof Download PDFInfo
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- CN111705176B CN111705176B CN202010438727.3A CN202010438727A CN111705176B CN 111705176 B CN111705176 B CN 111705176B CN 202010438727 A CN202010438727 A CN 202010438727A CN 111705176 B CN111705176 B CN 111705176B
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- C21B5/00—Making pig-iron in the blast furnace
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Abstract
The invention discloses a method for discharging slag iron by using an oxygen lance when a blast furnace is opened and the oxygen lance thereof. Meanwhile, the oxygen feeding proportion is controlled to reduce the burning loss speed of the oxygen lance to the minimum, the oxygen burning position of the oxygen lance is always kept at the proper depth of the furnace hearth, and the oxygen lance is ensured to burn coke in the furnace hearth for a long time without burning out an iron port channel. And the timing of pulling out the oxygen lance is accurately determined by controlling the three necessary conditions, so that the large quantity of iron slag for the first time, the sufficient temperature and the good fluidity are ensured, the slag bonding and iron bonding of an iron notch, an iron runner and a slag runner are avoided, the cost of manpower and material resources is reduced, the smooth upwind of the blow-in furnace is promoted, and the foundation is laid for quickly achieving the effect of the production.
Description
Technical Field
The invention relates to a blast furnace blow-in method, in particular to a method for discharging slag iron by using an oxygen lance during blow-in of a blast furnace and the oxygen lance.
Background
The blow-in of the blast furnace is a complicated system project and is a relatively complex practical operation in iron-making production. The blast furnace condition and the blow-in condition before blow-in are different, and the blow-in condition is also different greatly. The furnace opening modes adopted at present mainly comprise two main types, wherein the furnace opening is carried out by filling a hearth with sleepers mostly, and the furnace opening is carried out by fully coking a small part of the hearth.
In the process of opening the blast furnace, along with the combustion of coke in front of the tuyere, the convolution area is gradually formed, and the furnace charge is gradually heated and descended from bottom to top. The furnace burden is changed in physical and chemical ways along with the rise of the self heat, the soft melting belt is gradually formed and moved upwards, the block belt at the upper part in the furnace is used for preheating and indirectly reducing the furnace burden, after the furnace burden is soft melted and dripped, molten slag iron begins to form, and the molten slag iron descends to the bottom of the furnace hearth through the dead coke pile. During this period, whether the molten iron slag produced can be discharged smoothly for the first time is a comprehensive check of a series of production operations at the initial stage of the furnace opening.
In order to ensure smooth discharge of the slag iron during the furnace opening, the most important is a reasonable charging system, reasonable proportioning and good control of the slag iron components, and the slag iron has good fluidity even if the temperature of the initially generated slag iron is insufficient. In addition to this, the skilled person has also developed various aids for the taphole.
For example, a gas delivery pipe is installed at the taphole. After confirming that coke in front of the tuyere is burnt, opening a gas sealing cover of the iron notch to ignite the injected gas, discharging high-temperature gas in the furnace to heat a furnace hearth in the area of the iron notch, and plugging the iron notch when iron slag is sprayed out. The disadvantage of this method is that although the gas injected from the tap hole is ignited and then released into the atmosphere, the dust and harmful gas content in the blast furnace tap hole area is inevitably increased, and the working environment in front of the furnace is deteriorated. In addition, high-temperature coal gas in the furnace is discharged from the taphole for blowing, when the iron slag is generated and flows to the taphole, the air blowing is finished, and after the taphole is blocked, a certain amount of cold slag and cold iron which is initially generated in the taphole area is not heated continuously, so that the iron slag is still difficult to discharge.
In addition, a blast furnace uses an oxygen lance to assist in opening the furnace to discharge iron slag, and one means is to reserve steel pipes in an iron notch channel and a mud bag and adopt an electric control device to carry out automatic action control. Compared with a coal gas eduction tube, the method is technically improved, but the method is still lagged, and particularly, the method has the following defects that: the oxygen introduction time is slow, and the effect of heating furnace burden and iron slag is poor; the time for closing the compressed air is too early, so that the service life of the oxygen lance is shortened substantially, the steel pipe in the taphole channel is completely melted, iron slag can automatically flow out in an uncontrolled manner, the safety production risk of a stokehole worker is increased, and the refractory material of the taphole channel is easily burnt out by oxygen, so that hidden troubles are left for the long service life of the blast furnace.
The other means is that an oxygen lance is arranged on an iron notch before ignition and furnace opening, oxygen is fed to burn coke in a furnace hearth, and the air permeability of a material column at the lower part of the furnace hearth is increased, so that the furnace hearth can reach the working temperature as soon as possible, and the aim of quickly recovering the normal production level is fulfilled. However, the oxygen lance is charged with oxygen to burn coke in the hearth for too long time, the oxygen lance is greatly burnt short due to too much amount of iron slag generated by the hearth, the refractory of a channel in an iron notch area can be burnt to shorten the service life of the blast furnace, and even if the oxygen lance in the iron notch is completely melted, the risk of safety accidents caused by the fact that the iron slag automatically runs out of the iron notch is increased. The oxygen lance is pulled out when the time for the oxygen lance to feed oxygen to burn coke in the furnace hearth is too short, although the oxygen lance is intact, the furnace hearth cannot be fully heated, the oxygen lance is pulled out, the first slag iron is difficult to discharge, even the slag iron cannot flow out, the oxygen lance needs to be installed on the iron notch in a production state or the oxygen pipe needs to be manually inserted into the iron notch channel again to feed oxygen to melt the solidified slag iron in the furnace hearth, the workload in front of the furnace is increased, and the slag iron generated in the furnace hearth cannot be discharged in time to influence the process of blowing and air feeding. At present, the blast furnace adopting the method for blowing in the furnace still adopts the extensive control mode for the oxygen lance oxygen feeding time, the oxygen feeding proportion and the oxygen lance pulling time on the basis of the material guarantee of the oxygen lance, which often results in the two results and can not successfully assist in blowing in the furnace.
Disclosure of Invention
The purpose of the invention is as follows: in order to overcome the defects of the prior art, the invention provides a method for discharging iron slag by using an oxygen lance when a blast furnace is opened, which can avoid burning out refractory materials in an iron notch area, ensure that the first slag iron after the blast furnace is opened has a certain amount of slag iron, and ensure that the slag iron can smoothly flow out due to abundant heat.
The invention also aims to provide an oxygen lance for implementing the method for discharging the slag iron by using the oxygen lance when the blast furnace is opened.
The technical scheme is as follows: the invention relates to a method for discharging slag iron by using oxygen lances when a blast furnace is opened, which comprises the steps of installing sleeve type oxygen lances at all iron ports after filling materials are filled into the blast furnace and before air supply and ignition, introducing oxygen into the furnace through inner layer pipelines of the oxygen lances, wherein the oxygen pressure is 0.1Mpa, introducing compressed air into the furnace through outer layer pipelines of the oxygen lances, and keeping the pressure ratio of the oxygen to the compressed air to be 0.8-1.2: 1 all the time;
igniting, blowing in and blowing out, gradually increasing the oxygen pressure of the oxygen lance from 0.1Mpa to 0.4Mpa along with the air adding rhythm, and monitoring the hot air pressure of the blast furnace, the oxygen pressure of the oxygen lance and the pressure of the compressed air of the oxygen lance; and when the oxygen pressure of the oxygen lance automatically rises to 40-60 Kpa, the hot air pressure in the blast furnace automatically rises to 10-30 Kpa, and the second section of empty coke slag-making materials filled in the blow-in filling material completely reach the position of the tuyere through wind consumption calculation, pulling out the oxygen lance to obtain the first slag iron.
Further, the method also comprises the step of verifying the time for pulling out the first slag iron of the oxygen lance by calculating the safe storage volume of the slag liquid level reaching the hearth.
Specifically, the verification method is as follows:
calculating the safe reserve volume between the iron notch and the central line of the tuyere
The limit volume of the slag iron in the furnace hearth is V multiplied by xi multiplied by k
Wherein h is the height from the central line of the tuyere to the central line of the taphole, and the unit is meter; d is the diameter of the hearth, and the unit is meter; xi is the void ratio after the coke is filled in the hearth; k is the insurance coefficient;
and (4) according to the batch number of the running materials, checking that an iron notch is opened for tapping when the volume of the produced iron slag reaches the limit volume of the iron slag storage in the furnace hearth.
The length of the oxygen lance is consistent with that of a drill rod of a blast furnace iron notch tapping machine, the oxygen lance is inserted into the furnace from the iron notch through the tapping machine, and the oxygen lance is pulled out through the tapping machine when first iron slag is discharged.
In order to implement the method for discharging the slag iron by using the oxygen lance for blowing in the blast furnace, the technical scheme adopted by the oxygen lance provided by the invention is as follows: the oxygen lance comprises an inner layer pipeline, an outer layer pipeline sleeved outside the inner layer pipeline, a compressed air inlet pipe arranged on the side surface of the outer layer pipeline, an oxygen inlet pipe arranged side by side with the compressed air inlet pipe, a compressed air valve and a compressed air pressure gauge arranged on the compressed air inlet pipe, and an oxygen valve and an oxygen pressure gauge arranged on the oxygen inlet pipe; the compressed air inlet pipe is communicated with the outer layer pipeline, and the oxygen inlet pipe is inserted into the outer layer pipeline and communicated with the inner layer pipeline.
Specifically, the inner layer pipeline and the outer layer pipeline are both closed at the tail end, and the tail part of the outer layer pipeline is provided with a threaded connector matched with the iron notch tapping machine.
The inner layer pipeline, the outer layer pipeline, the oxygen intake pipe and the compressed air intake pipe are all made of stainless steel materials and are formed by welding.
Has the advantages that: the method selects the time for introducing oxygen after the filling material is fed into the furnace and before ignition and air supply, ensures that the coke in the furnace hearth can be fully combusted, promotes the rapid recovery of the heat of the furnace hearth, and provides abundant heat support for the first slag iron. Meanwhile, the oxygen feeding proportion is controlled to reduce the burning loss speed of the oxygen lance to the minimum, the oxygen burning position of the oxygen lance is always kept at the proper depth of the furnace hearth, and the oxygen lance is ensured to burn coke in the furnace hearth for a long time without burning out an iron port channel. And the timing of pulling out the oxygen lance is accurately determined by controlling the three necessary conditions, so that the large quantity of iron slag for the first time, the sufficient temperature and the good fluidity are ensured, the slag bonding and iron bonding of an iron notch, an iron runner and a slag runner are avoided, the cost of manpower and material resources is reduced, the smooth upwind of the blow-in furnace is promoted, and the foundation is laid for quickly achieving the effect of the production.
Drawings
FIG. 1 is a schematic structural view of a blast furnace blow-in oxygen lance in a use state;
FIG. 2 is the variation trend of the hot air pressure and the total pressure difference of the blast furnace in the stage of burning oxygen to produce the first iron slag in the example.
Detailed Description
The process of the present invention is carried out using an oxygen lance as shown in FIG. 1. Wherein, 1 is outer pipeline, 2 is the oxygen manometer, 3 is the compressed air manometer, 4 is the compressed air intake pipe, 5 is the oxygen intake pipe, 6 is the compressed air valve, 7 is the oxygen valve, 8 is the iron notch passageway, 9 is the furnace hearth, stove bottom brick lining, 10 is the stave, 11 is the furnace skin. The method can be applied to the first slag iron discharging operation of each iron notch in all blast furnace full coke blow-in production processes, in particular to 2500m3The full coke blow-in effect of the intermediate repair and the top repair of the blast furnace is particularly obvious.
Specifically, the process from the furnace opening to the first iron slag discharging is as follows:
1) and under the condition of permission of enterprise resources, selecting raw fuel and auxiliary materials with good quality as much as possible and blowing the raw fuel and the auxiliary materials into the furnace.
2) And under the condition of permission of enterprise resources, the ore-using structure with higher clinker rate (more than or equal to 90%) is selected to blow in the furnace as much as possible.
3) And the whole coke is opened, and no sleeper or miscellaneous wood is arranged in a hearth.
4) Blowing-in filling material ingredient
The blast furnace filling material is divided into a plurality of sections according to the requirement, and the total coke ratio of the filling material is 3.0-4.0 t/t. The batch weight of each section of coke is kept consistent, and the coke batch weight ensures that the thickness of the coke layer at the furnace waist part reaches 0.2-0.3 m.
The first section of the filling material is clean coke and is filled from the hearth to the upper edge of the furnace belly.
The second section is empty coke slag making material which is filled to the lower part of the furnace body from the furnace waist, and the height filled in the furnace body accounts for 20 +/-5 percent of the height of the furnace body. Among them, the air coke is slag forming material including coke, alkaline flux (e.g., limestone, dolomite), acid flux (e.g., silica), stone material for improving slag fluidity such as fluorite. Considering that the temperature of the first slag tapping iron furnace is lower, Al in the air coke is required2O3The mass percentage content of the Al is not more than 13 percent, and the Al is gradually increased from the second section of empty coke slag-making material to each section of material2O3In order to reduce the slag ratio, Al2O3The highest mass percentage content of the component (A) is not more than 14.5 percent.
The ore is added into the third section of the filling material, the coke load of the third section is controlled to be 0.2, and then the coke load of each section of the filling material is gradually increased by 0.2-0.3 compared with the coke load of the previous section of the filling material and shows a smooth rising trend. The load is particularly increased in a manner that increases ore batch weight and fixes coke batch weight.
From the second section, the MgO content of the slag is determined according to MgO and Al2O3The mass ratio of the slag is controlled to be 0.6-0.65, and the alkalinity of the slag is controlled to be 0.95 +/-0.05. And, starting from the second section, each batch is prepared with fluorite, and the dosage of the fluorite is 5 +/-1% of the batch weight. In addition, the filler is [ Si ] in molten iron]Controlled to be 2.5-3.5%, [ Mn%]The control is 0.8 +/-0.1%.
The proportion of the iron materials for normal production, including sintered ore, pellet ore and lump ore, is kept stable according to the needs, the coke load and the slag iron components gradually tend to be normalized through sectional batching, and the temperature field, the pressure field and the concentration field in the blast furnace gradually transition to normal levels.
5) The requirement for the filling material in the blast furnace
Firstly, adjusting a material distribution matrix in the process of filling materials. After the filling process is finished, the charge level in the furnace is required to form a platform and a funnel charge level with proper width and depth.
② the difference between the actual material volume loaded into the furnace and the planned loading volume is less than 5 percent.
6) Before air supply and ignition, oxygen lances are installed at all iron ports to supply oxygen to burn coke in furnace hearth
Oxygen lance as shown: the material is stainless steel, and the oxygen rifle is double-barrelled structure, and the inner tube leads to oxygen, and compressed air is led to the outer tube, and oxygen rifle length is unanimous with indisputable mouthful tapping machine drill rod length, and the tail end sets up the threaded connection head of being connected with the tapping machine to accessible tapping machine inserts the oxygen rifle in the stove from the indisputable mouthful. And blowing oxygen and compressed air into the furnace through an oxygen lance, wherein the oxygen pressure is 0.1Mpa, and the pressure ratio of the oxygen to the compressed air is always maintained at 0.8-1.2: 1.
7) Igniting, blowing in and gradually increasing the oxygen pressure of the oxygen lance from 0.1Mpa to 0.4Mpa along with the air feeding rhythm, and monitoring the hot air pressure of the blast furnace, the oxygen pressure of the oxygen lance and the pressure of the compressed air of the oxygen lance; and when the oxygen pressure of the oxygen lance automatically rises to 40-60 Kpa, the hot air pressure in the blast furnace automatically rises to 10-30 Kpa, and the second section of empty coke slag-making materials filled in the blow-in filling material completely reach the position of the tuyere through wind consumption calculation, pulling out the oxygen lance to obtain the first slag iron. It should be noted that, of the three requirements, especially the first two requirements are sufficient to indicate that a certain level of slag iron is accumulated in the hearth until the time of slag iron tapping by the oxygen lance. Of course, in order to further confirm whether the time judgment is accurate, the time for pulling out the oxygen lance for the first time of slag iron can be verified by calculating the safe storage volume of the slag liquid level reaching the hearth.
Next, 2550m at a certain domestic factory3The present invention will be described in further detail with reference to a blast furnace as an example.
1) Before the blast furnace is opened
The 2550m3The blast furnace is subjected to furnace shutdown and cooling wall replacement after two times of water pumping and material emptying lines reach the position below a furnace hearth tuyere.
The 1 st item repair is 4 months, 30 days, 2:23 ignition blow-in 2009. Residual broken coke in the furnace is basically cleaned out before the furnace is opened, two of three iron openings are burnt out of the furnace, and 4 air openings are provided with hot air guide pipes. The blast furnace is started for 2 blast furnaces, the self-production dry quenching coke of the plant is sufficient, the full-self-production dry quenching coke can be kept after the blast furnace is started, but the first slag iron production is difficult after the blast furnace is started, and the time for production is long.
The 2 nd project repair is 2019, 4 months, 30 days, 19:16 ignition blow-in. 4, 1 day, blowing out the furnace through an empty stockline for 29 days, and replacing 176 blocks of copper cooling walls and 99 blocks of cast iron cooling walls. Due to the limitation of the time of blowing in, the furnace is raked to the average 2.59 meters below the central line of the tuyere before the furnace is blown in, and three iron openings are basically dug out (the direction of the three iron openings is 4.14 meters, 3.88 meters and 4.48 meters below the central line of the tuyere at the deepest position of digging), but are not communicated, and the furnace cylinder is about 166m3The residual coke and slag iron condensate are not removed. The self-produced dry quenching coke of the factory is only enough for 2 blast furnaces to produce. The self-production dry quenching amount of 3 blast furnaces is insufficient during the 2 nd repair blow-in, and the self-production dry quenching proportion is reduced from 100% to 55% after ignition blow-in. The difficulty of opening the furnace for the 2 nd time of project repair is greater than that of the last time.
The blast furnace blow-in for the 2 nd time of the top repair adopts the method for discharging the slag iron by using the oxygen lance, the slag iron is discharged smoothly when the blast furnace is blown in, and the yield is high.
2) And the blowing-in filling material is a self-produced dry quenching full coke blowing-in furnace.
3) And the structure of the ore for opening the furnace is a structure of 84.2 percent of sinter and 15.8 percent of pellet fully-cooked material.
4) The quality of the raw fuel meets the requirement of furnace opening
5) And measuring the filling volume of the blast furnace.
Before charging, the filling volume of the blast furnace is measured by a 3D scanner, and the total volume of the blast furnace is calculated to be 2492.2m according to the measurement results of each part3Working volume is 2182.6m3。
6) Blow-in charge filling
The blowing-in filler has a 10-section structure. The coke batch is fixed to 17 tons, the first stage material 30 batches of clean coke are totally added to the upper edge of the furnace belly, the second stage material 18 batches of empty coke are added to the position 3.4 meters below the furnace body, wherein the clean coke is 306 tons, the fluorite is 5.4 tons, the limestone is 45 tons, the dolomite is 41.4 tons, and the silica is 21.6 tons. The third to tenth sections are 30 normal batches of materials, the number of the batches is respectively as follows: 5. 5, 4, 3 and 2, wherein the ore batches are respectively as follows: 3.4t, 6.8t, 11.9t, 17t, 22.1t, 27.3t, 32.3t and 37.4t, and the O/C is respectively 0.2, 0.4, 0.7, 1.0, 1.3, 1.6, 1.9 and 2.2. And stopping filling the furnace burden after the ninth section of the material is added, wherein the material lines of the south mechanical stock rod and the north mechanical stock rod are 3.24 meters and 2.92 meters respectively, and the tenth section of the material is remained, and the ignition air supply material is added after the ignition air supply material is moved. The normal material line is set to be 1.5 meters, the coke ratio of the whole furnace is 3.82t/t, the O/C is 0.407, 440 tons of sintered ore, 82.7 tons of pellet ore, 23.3 tons of manganese ore, 14.7 tons of fluorite, 88 tons of limestone, 92.6 tons of dolomite and 78.3 tons of silica. Finally, the material distribution matrix of the 2 cans is shown in table 1.
TABLE 1 Final 2 pots of Filler distribution matrix
The strand was 3.45m, the platform width 1.1m, the funnel depth 1.4m, the funnel diameter 2.67m, and no segregation in the circumferential direction, measured according to the final charge level. Theoretically calculating that the stockline is 3.8 meters after the 9 th section of material is filled, the average stockline of the mechanical stock rod is 3.08 meters after the 9 th section of material is actually filled, and the difference between the volume of the material actually filled into the furnace and the planned filling volume is 2115-2075-40 m3The error is 1.93%.
7) 3 oxygen lances are installed on the iron notch to deliver oxygen to burn coke in the hearth and heat the hearth
Oxygen supplying is well carried out on the No. 5 and No. 6 iron mouth oxygen lances 15: 334 after 4 months and 30 days, and oxygen supplying is well carried out on the No. 5 and No. 6 iron mouths before air supplying and ignition, and coke is burnt by supplying oxygen into a furnace hearth. At the initial stage of blowing oxygen into the furnace, the oxygen pressure was set at 0.1MPa, and the ratio of oxygen to air was maintained at 1: 1.
8) And an oxygen lance is used for passing after ignition and furnace opening.
19:16 air supply ignition blow-on in 2019, 4 month, 30 days and 823m air supply volume3The air ports of 20: 0113 #, 15# are firstly lightened at the temperature of 805 ℃ in min and 21:0And (4) the air ports opened at 0 are all bright, the coal gas is arranged to be qualified in the furnace top coal gas explosion test, and the coal gas is introduced successfully at a ratio of 22: 27.
Adding 3:38 min of wind amount to 2711m in 1 day and 5 months3Min, 6:00 air volume has been added to 2977m3And/min. At the moment, the oxygen lance oxygen blowing pressure is gradually increased and set to be 0.4Mpa, the ratio of oxygen to air is still maintained at 1:1, and the oxygen lance oxygen blowing pressure automatically rises to 0.45Mpa when the ratio is 6: 45. The hot blast pressure of the blast furnace at 6:00 is 229Kpa, then the automatic climbing slowly rises, the 7:04 point rises to 241.9Kpa, and the hot blast pressure rises to 12.9 Kpa. Specifically, see fig. 2, the variation trend of hot air pressure and total pressure difference of 6: 00-8: 00. It shows that the furnace hearth stores a certain amount of iron slag, which causes the blast furnace wind pressure and the iron mouth oxygen lance pressure to rise.
According to the calculation of air consumption, the time from the second stage of air-coke slagging of the charge material to the air inlet of the blow-in furnace is 4: 00-8: 00 (9-13 h after ignition and air supply), and the amount and volume of iron slag generated by the charge material smelting at each stage are shown in the table 2.
TABLE 2 amount and volume of iron slag generated by the filler smelting in each stage of the blow-in
In order to discharge the second section of empty coke slag-making materials of the blow-in filling materials from the iron notch completely before 8:00 and facilitate the air-adding process, a 6:55 tapping machine is used for drawing a 6# iron notch oxygen lance to discharge iron slag, the iron slag smoothly flows out and has good fluidity after the oxygen lance is withdrawn, the iron slag mainly comprises slag and little amount of molten iron, the iron notch is sprayed after 40 minutes of continuous slag discharge, and the slag components are as follows: r2＝0.87、Al2O3＝11.56％、MgO＝7.33％，MgO/Al2O30.63; 7:36 drawing the No. 6 iron-mouth oxygen lance, smoothly tapping for 10 minutes, then plugging the mouth, wherein the slag components are as follows: r2＝0.92、Al2O312.3%, 7.9% MgO, 0.64% MgO/Al2O 3; 7:49 drawing 5# iron mouth oxygen lance, smoothly discharging slag for 2 minutes, then blocking the iron mouth by large jet, and obtaining slag component R2＝0.94、Al2O3＝12.71％、MgO＝8.12％，MgO/Al2O30.63. Slag produced by furnace hearth after three iron-mouth oxygen lances are pulled outThe iron flows out smoothly from the iron notch, the fluidity is good, the slag iron channel does not form slag and iron, the slag iron is blocked by a hydraulic mud gun after being discharged completely, and the iron notch does not need to be buried in an oxygen gun. The workload in front of the blast furnace is greatly reduced, and the hot air pressure is reduced by 7Kpa (as shown in figure 2) after a large amount of generated iron slag is discharged in time, so that conditions are created for adding air into the blast furnace and rapidly achieving the yield.
13:09, arranging the No. 6 tap hole to discharge the first iron (which is different from the slag tapping link, namely the formal tapping), wherein the time from the blow-in of the furnace is 17.88 hours. At the moment, the charge is discharged into the hearth in the eighth stage, the tapping amount is 70.45 tons in 47 minutes of tapping, the temperature of the molten iron is 1400 ℃, and the molten iron [ Si ] is]＝2.62％、[Mn]＝0.71％、[S]0.009%, slag composition: r2＝0.97、Al2O3＝13.85％、MgO＝8.39％，MgO/Al2O3When the slag iron is 0.61, the slag iron flows smoothly, the slag iron groove does not form a groove and is not slagged, the iron groove does not stick iron, and the furnace is opened successfully.
The 14:06 air quantity is added to 3454m3Permin, oxygen enrichment of 3647m3/h。
Opening the taphole at the ratio of 15:21 of the No. 2 furnace iron, delivering the filler to the hearth at the tenth section (coke load of 2.20), tapping 103.05 tons at the molten iron temperature of 1430 ℃, and discharging the molten iron [ Si]＝2.18％、[Mn]＝0.71％、[S]0.005%, slag composition: r2＝0.97、Al2O3＝13.93％、MgO＝8.55％，MgO/Al2O3And (5) 0.61, till all the blowing-in filling materials are completely burnt through the tuyere, smoothly entering a loading coal injection oxygen-enriched smelting period.
17:51 air volume is added to 3665m3And/min. 20:15 oxygen addition 1000m3H to 5000m3H is used as the reference value. 5 months and 2 days with 1:00 air volume 4026m3Permin, oxygen enrichment of 5160m3H is used as the reference value. 3 days 2:00 air volume 4166m3Min, oxygen enrichment 5963m3H is used as the reference value. 6:00 oxygen up to 9000m3At this time, the air volume is 4658m3And/min. 10:00 air quantity added to 4751m3At/min (63 h after ignition), the oxygen enrichment was 9652m3/h, so far the air volume had been added to the full air volume. Yield on day 3: the blast furnace utilization coefficient is 2.1t/m3d; the yield of molten iron on day 4 is 6279 tons, and the utilization coefficient of the blast furnace is 2.46t/m3d (see table 3), has reached the normal production level, realizes the quick blow-inThe production target is reached quickly.
TABLE 3 molten iron yield 4 days before opening the furnace
| |
5 months and 1 |
5 months and 2 |
5 months and 3 |
5 months and 4 days |
| Molten iron yield (t) | 1021.6 | 2987.2 | 5358.3 | 6279.3 |
| Blast furnace utilization factor (t/m3d) | 0.40 | 1.17 | 2.10 | 2.46 |
Therefore, on the basis that the objective difficulty of the blast furnace blowing-in for the 2 nd overhaul is far greater than that of the 1 st overhaul, by adopting the method for discharging the slag iron by using the oxygen lance for the blast furnace blowing-in, the tapping is smooth after the blast furnace is blown in, the fluidity of the slag iron is good, and the temperature field, the pressure field and the concentration field in the blast furnace are quickly transited to the normal level, so that the yield reaching effect is far better than that of the 1 st overhaul.
Claims (3)
1. A method for discharging slag iron by using an oxygen lance for blast furnace blow-in is characterized in that after filling materials are filled into a blast furnace, before air supply and ignition, sleeve type oxygen lances are installed on all iron ports, the length of each oxygen lance is consistent with the length of a drill rod of a blast furnace iron port tapping machine, the oxygen lances are inserted into the furnace from the iron ports through the tapping machines, oxygen is introduced into the furnace through inner layer pipelines of the oxygen lances, the oxygen pressure is 0.1Mpa, compressed air is introduced into the furnace through outer layer pipelines of the oxygen lances, and the pressure ratio of the oxygen to the compressed air is maintained to be 0.8-1.2: 1 all the time;
igniting, blowing in and blowing out, gradually increasing the oxygen pressure of the oxygen lance from 0.1Mpa to 0.4Mpa along with the air adding rhythm, and monitoring the hot air pressure of the blast furnace, the oxygen pressure of the oxygen lance and the pressure of the compressed air of the oxygen lance; when the oxygen pressure of the oxygen lance automatically rises to 40-60 Kpa, the hot air pressure in the blast furnace automatically rises to 10-30 Kpa, and the second section of empty coke slag-making materials filled in the blow-in filler are determined to completely reach the position of the tuyere through wind consumption calculation, the oxygen lance is pulled out through an opening machine to slag iron for the first time;
wherein the first section of the filling material is clean coke and is filled from the hearth to the upper edge of the furnace bosh; filling the second section of filling material hollow coke slag-making material into the lower part of the furnace body from the furnace waist, wherein the filling height of the furnace body accounts for 20 +/-5% of the height of the furnace body, and Al in the hollow coke2O3The mass percentage content of the Al is not more than 13 percent, and the Al is gradually increased from the second section of empty coke slag-making material to each section of material2O3In order to reduce the slag ratio, Al2O3The highest mass percentage content of the component (A) is not more than 14.5 percent; the third section of the filling material is added with the ore, the coke load of the third section is controlled to be 0.2, and then the coke load of each section of the filling material is gradually increased by 0.2-0.3 compared with the coke load of the previous section of the filling material and is in a smooth rising trend; from the second section, the MgO content of the slag is determined according to MgO and Al2O3The mass ratio of the slag is controlled to be 0.6-0.65, and the alkalinity of the slag is controlled to be 0.95 +/-0.05; filling material of [ Si ] in molten iron]Controlled to be 2.5-3.5%, [ Mn%]Controlling the concentration to be 0.8 +/-0.1%; the coke weight of the filling material is kept consistent, and the coke weight ensures that the thickness of a coke layer at the furnace waist part is 0.2-0.3 m; coke loading is increased by increasing ore batch weight and fixing coke batch weight starting from the third stage.
2. The method for discharging the iron slag by the oxygen lance for the blast furnace blow-in according to claim 1, further comprising verifying the time for pulling out the oxygen lance for the first time of slag iron by calculating the safe storage volume of the slag liquid level reaching the hearth.
3. The method for discharging the slag iron by using the oxygen lance for the blast furnace blow-in according to the claim 2 is characterized in that the verification method is as follows:
calculating the safe reserve volume between the iron notch and the central line of the tuyere
The limit volume of the slag iron in the furnace hearth is =
Wherein the content of the first and second substances,hthe height from the central line of the tuyere to the central line of the taphole is measured in meters;dis the diameter of the hearth, and the unit is meter;
the void fraction after filling the hearth with coke;Kis the safety factor;
and (4) according to the batch number of the running materials, checking that an iron notch is opened for tapping when the volume of the produced iron slag reaches the limit volume of the iron slag storage in the furnace hearth.
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| CN112575135A (en) * | 2020-12-25 | 2021-03-30 | 北京金泰烁昌科技有限公司 | Blast furnace taphole dredging and blockage removing equipment and using method thereof |
| CN113621744A (en) * | 2021-08-10 | 2021-11-09 | 广东韶钢松山股份有限公司 | Method for first iron discharging during blast furnace opening |
| CN113528735A (en) * | 2021-08-30 | 2021-10-22 | 新疆八一钢铁股份有限公司 | Iron mouth oxygen lance for Ou smelting furnace |
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