CN111254253B - Method for improving pouring amount of dephosphorization residues in dephosphorization period of converter double-residue process - Google Patents
Method for improving pouring amount of dephosphorization residues in dephosphorization period of converter double-residue process Download PDFInfo
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- CN111254253B CN111254253B CN202010246787.5A CN202010246787A CN111254253B CN 111254253 B CN111254253 B CN 111254253B CN 202010246787 A CN202010246787 A CN 202010246787A CN 111254253 B CN111254253 B CN 111254253B
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/30—Regulating or controlling the blowing
- C21C5/35—Blowing from above and through the bath
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/36—Processes yielding slags of special composition
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Abstract
The invention discloses a method for improving pouring amount of dephosphorization residues in a converter double-residue process dephosphorization period, belongs to the technical field of converter steelmaking, and solves the problems of difficult pouring of the dephosphorization residues in the dephosphorization period and low pouring amount of the dephosphorization residues in the prior art. A method for improving pouring amount of dephosphorization residues in a converter double-slag process dephosphorization period comprises the following steps: step 1: after the smelting in the dephosphorization period is finished and before the converter tilts, nitrogen is firstly used for slagging; step 2: and rotating the converter to dump the dephosphorized slag after slagging in the dephosphorizing period, and controlling the air supply flow of the bottom blowing air supply element to change along with the tilting angle alpha of the converter. The invention realizes that the pouring amount of the dephosphorization residues in the dephosphorization period is increased to 50-70% from the original 30-50%, and the phosphorus content of the molten steel at the end point is averagely reduced by 0.001-0.005%.
Description
Technical Field
The invention relates to the technical field of converter steelmaking, in particular to a method for improving pouring amount of dephosphorization residues in a converter double-residue process dephosphorization period.
Background
Because the converter double-slag smelting process can successfully remove more molten iron phosphorus into the dephosphorized slag at the early stage of the converter smelting by using the low-temperature thermodynamic conditions, the discharge of the dephosphorized slag directly influences the phosphorus load of a molten pool in the decarbonization stage of the converter and further influences the dephosphorization efficiency of the converter smelting process. In order to improve the dephosphorization effect in the dephosphorization stage, the dephosphorization slag in the dephosphorization stage has high viscosity and is easy to foam, so that the dephosphorization slag can be poured out smoothly and sufficiently.
The prior process method for improving the slag pouring amount in the dephosphorization stage of the converter comprises the following steps: (1) controlling the charging amount of furnace burden in the dephosphorization stage; the mass fraction of MgO and FeO in the dephosphorization slag; dephosphorizing the end point temperature; the pouring amount of the dephosphorization slag is stably controlled to be 50-60 percent according to important parameters such as the furnace shaking angle, the duration and the like; (2) the carbon material is contacted with the foaming slag on the surface of the molten steel in the converter reversing process, so that the effective inhibition of slag foaming is realized; (3) blowing nitrogen gas by using a top gun or (adding cold materials and blowing nitrogen gas), cooling the dephosphorized foamed slag, and ensuring the slag pouring rate of the dephosphorized slag; (4) the converter slag is poured out by a mechanical slag skimming method.
Although the pouring of the dephosphorization residues is improved to a certain extent by the method for controlling the foaming degree of the dephosphorization residues or mechanically skimming through physical chemistry or physical chemistry, the stability of the pouring effect of the dephosphorization residues is influenced by the problems of increased difficulty of the control process, mechanical skimming safety, prolonged time and the like caused by the difference between the furnaces, and the requirement of pouring the dephosphorization residues is difficult to stably meet.
Disclosure of Invention
In view of the above analysis, the embodiment of the present invention aims to provide a method for increasing the pouring amount of the dephosphorization residues in the dephosphorization period of the converter dual-residue process, so as to solve the problem of difficult pouring of the existing dephosphorization residues.
The invention is realized by the following technical scheme:
a method for improving pouring amount of dephosphorization residues in a converter double-slag process dephosphorization period comprises the following steps:
step 1: after the smelting in the dephosphorization period is finished and before the converter tilts, nitrogen is firstly used for slagging;
step 2: and rotating the converter to dump the dephosphorized slag after slagging in the dephosphorizing period, and controlling the air supply flow of the bottom blowing air supply element to change along with the tilting angle alpha of the converter.
Further, the control process in the nitrogen slagging in the step 1 is as follows: the nitrogen blowing pressure is more than 0.7MPa, the continuous nitrogen blowing time is more than 120s and more than t and more than 30s, and the nitrogen blowing gun position is more than 2.5 m.
Further, in the step 2, when the tilting angle is more than 80 degrees and alpha is more than or equal to 0 degrees, the bottom blowing gas supply element distributes the bottom blowing gas evenly, and the single-branch bottom blowing gas supply flow is controlled to be 30-80 Nm3H; when the tilting angle alpha is more than or equal to 80 degrees, the bottom blowing air supply element adopts the regional control.
Further, when the tilting angle alpha is more than or equal to 80 degrees, the bottom blowing gas supply element immersed by the molten steel controls the single-branch bottom blowing gas supply flow to be 30-80 Nm3H; a bottom-blowing gas supply element which is not immersed by the molten steel controls the single-branch bottom-blowing gas supply flowIn an amount of > 150Nm3/h。
Furthermore, the thickness of the slag splashing layer above the bottom blowing gas supply element is less than or equal to 50 mm.
Furthermore, the variation range of the tilting angle alpha is more than or equal to 0 degrees and less than or equal to 180 degrees.
Further, the flow regulating range of the bottom blowing air supply element is 20-200 Nm3/h，
Further, the air supply pressure of the bottom blowing air supply element is adjusted within the range of 0.2-1.5 MPa.
Further, the number of bottom blowing gas supply elements is more than or equal to 2.
Further, the bottom blowing gas supply elements are uniformly distributed along the central line of the rotary trunnion of the converter in an annular uniform distribution mode or a rectangular uniform distribution mode.
Compared with the prior art, the invention can realize at least one of the following beneficial effects:
1. when deslagging is carried out in the dephosphorization period, top-blown nitrogen is firstly used for deslagging before the converter rotates, and the deslagging process comprises the following steps: the nitrogen blowing pressure is more than 0.7MPa, the continuous nitrogen blowing time is more than 120s and t and more than 30s, the nitrogen blowing gun position is more than 2.5m, the sliding gun operation is adopted, and the time is saved by 1-2 min for the nitrogen deslagging process for pouring the dephosphorization slag in the whole dephosphorization period.
2. The invention adjusts the relationship between the rotation angle of the converter and the air supply flow: when the inclination angle is more than 80 degrees and alpha is more than or equal to 0 degrees, the bottom blowing gas supply element evenly distributes the bottom blowing gas, and the flow rate of the single-branch bottom blowing gas supply is controlled to be 30-80 Nm3H; when the tilting angle alpha is more than or equal to 80 degrees, the air supply flow of the bottom blowing air supply element is controlled by regions, and for the bottom blowing air supply element immersed by molten steel, the single-branch bottom blowing air supply flow is controlled to be 30-80 Nm3H; for the bottom-blowing gas supply element which is not immersed by the molten steel, the flow rate of the single-branch bottom-blowing gas supply is controlled to be more than 150Nm3H; when the tilting angle is less than 80 degrees, the bottom blowing gas supply element distributes gas evenly, and the single-branch bottom blowing gas supply flow is controlled to be 30-80 Nm3And the phosphorous removal rate is improved from 30-50% to 50-70%.
3. According to the invention, the nitrogen slagging is firstly carried out, the rotation angle of the converter is adjusted, and the gas supply flow is adjusted, so that the pouring amount of the dephosphorization slag in the dephosphorization period of the converter is increased, the smelting effect can be improved on the basis, the phosphorus content of the molten steel at the end point is reduced by 0.001-0.005%, the decarburization slag amount is reduced by 10-20%, and the consumption of slag materials such as lime is reduced by about 10%.
4. The invention is based on the arrangement of bottom blowing elements, and realizes the purposes of improving the pouring amount of the dephosphorization residues in the dephosphorization period of the converter double-residue process and increasing the pouring amount of the dephosphorization residues by controlling the nitrogen slagging process, the rotation angle of the converter and the gas supply flow.
In the invention, the technical schemes can be combined with each other to realize more preferable combination schemes. Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and drawings.
Drawings
The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the invention, wherein like reference numerals are used to designate like parts throughout.
FIG. 1 is a schematic side view (inclination angle 95 °) of a dephosphorization slag purged by bottom-blowing gas according to the present invention;
FIG. 2 is a schematic front view (90 ℃ inclination angle) of the dephosphorization slag purged by the bottom-blowing gas according to the present invention;
FIG. 3 is a schematic view of the bottom blowing gas supply elements of the present invention arranged annularly and uniformly;
FIG. 4 is a schematic view of rectangular uniform distribution of bottom blowing gas supply elements according to the present invention;
reference numerals:
1-converter shell; 2-foaming dephosphorizing slag; 3-semi-steel molten steel; 4-bottom blowing gas supply element; 5-rotary trunnion of the converter.
Detailed Description
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate preferred embodiments of the invention and together with the description, serve to explain the principles of the invention and not to limit the scope of the invention.
The design idea of the invention is as follows: due to the strong impact of the oxygen jet on the molten pool and the boiling action of CO bubbles, three phases of metal, slag and gas on the upper part of the molten pool are mixed vigorously to form a developed emulsified and foamed state in the converter. Therefore, the method firstly performs nitrogen purging and slagging to break emulsified foam, reduce the volume of the slag and facilitate later pouring of the slag; the converter is then rotated again to dump the slag.
The converter smelting of the invention adopts the double-slag process operation, and the dephosphorization slag is poured out after the dephosphorization period smelting, and the beneficial effects comprise the following aspects:
a. because the quantity of the removed phosphorus is large, or because the silicon content of the molten iron is high, the added slag is more, and therefore, the formed slag quantity is large. The slag dumping can eliminate the splashing caused by excessive slag quantity.
b. The alkalinity of the slag in the early stage of converting is low, a large amount of phosphorus is oxidized into the slag, and the deslagging can achieve a higher dephosphorization effect. Meanwhile, after the initial acid slag is poured out, the corrosion to a furnace lining can be reduced, and the consumption of lime is reduced.
The invention provides a method for improving pouring amount of dephosphorization residues in a converter double-slag process dephosphorization period, which comprises the following steps:
step 1: and (3) after the dephosphorization period smelting is finished (oxygen blowing is finished and an oxygen lance is lifted) and before the converter tilts, carrying out nitrogen slagging, wherein the slagging process comprises the following steps: the nitrogen blowing pressure is more than 0.7MPa, the continuous nitrogen blowing time is more than 120s and more than t and more than 30s, the nitrogen blowing gun position is more than 2.5m, and the sliding gun operation is adopted; the nitrogen can be replaced by argon and CO2CO, etc.
The nitrogen blowing time is determined according to the slag level of the dephosphorization slag in the furnace, the purpose of nitrogen blowing is to reduce the slag level, and the setting of the technological parameters of nitrogen slagging is to realize the effective control of the slag level and prevent the splashing in the dumping process. Different from the prior art, the nitrogen blowing and slag removing method adopts a sliding gun, namely the gun position is not fixed, and the staying time of one gun position is not more than 30 s; the gun position is not fixed, but cannot be too low, and is higher than 2.5m, the gun position is too low, gas enters a molten pool, not only can not press slag, but also blows out the slag, and if the gun position is too high, the slag is blown into molten steel, so that the molten steel is polluted;
step 2: after the dephosphorization period smelting is finished (oxygen blowing is finished and the oxygen lance is lifted), the gas flow of the single-branch bottom blowing is reduced:
when the inclination angle is more than 80 degrees and alpha is more than or equal to 0 degrees, the bottom blowing gas supply element evenly distributes the bottom blowing gas, and the flow rate of the single-branch bottom blowing gas supply is controlled to be 30-80 Nm3/h；
When the tilting angle alpha is more than or equal to 80 degrees, the air supply flow of the bottom blowing air supply element is controlled by regions, and for the bottom blowing air supply element immersed by the molten steel, the single-branch bottom blowing air supply flow is controlled to be 30-80 Nm3H; for the bottom-blowing gas supply element which is not immersed by the molten steel, the flow rate of the single-branch bottom-blowing gas supply is controlled to be more than 150Nm3H; at this point, deslagging begins.
After the slag dumping is finished, the converter rotates towards the central shaft direction of the converter, the tilting angle of the converter is less than 80 degrees at the moment, the bottom blowing gas supply element distributes gas evenly, and the single-branch bottom blowing gas supply flow is controlled to be 30-80 Nm3H is used as the reference value. The rotating inclination angle of the converter is calculated by that the converter is upright, the angle on the furnace mouth is zero, and the converter is inclined forward, namely the rotating inclination angle of the converter is the angle of the central line of the converter deviating from the vertical line.
Specifically, in step 1, the purpose of top-blowing nitrogen gas by rotating the converter is slagging. After dephosphorization smelting is finished, slag foams, so that the volume of the slag is increased, the slag easily overflows from a furnace mouth, and the slag is not easy to pour. The nitrogen is beaten the sediment and can compress the slag volume, does benefit to the slag and pours out smoothly. The nitrogen blowing pressure is higher than 0.7MPa, the nitrogen blowing pressure is too low, the nitrogen slagging effect is poor, and the volume of the furnace slag cannot be effectively reduced; the sliding gun operation is adopted, the continuous nitrogen blowing time is more than 120s and more than t and more than 30s, the nitrogen blowing time is too short and less than 30s, and the slag removal cannot be fully carried out; and (4) blowing nitrogen for longer than 120s, finishing slag removal and enabling nitrogen to be excessive. The nitrogen slagging is the pouring process of the dephosphorization slag in the whole dephosphorization period, and the time is saved by 1-2 min.
Specifically, the reason for reducing the gas flow rate of the single branch after the converter is rotated in step 2 is that the dephosphorization process is finished and the slag-steel mixing is reduced. Because the metal iron can enter the steel slag from the molten steel after the slag steel is mixed, the pouring proportion of the metal iron can be increased in the slag pouring process.
In the dephosphorization period of the converter, because of decarburization in the molten steelThe oxidation reaction of CO and other elements generated by the reaction causes the steel slag suspended on the upper surface of the molten steel to be violently mixed with three phases of molten steel, steel slag and gas on the upper part of a molten pool under the impact of top blowing and bottom blowing gas, so that a developed emulsified and foamed state in the converter is formed, and the dephosphorization slag is not easy to pour out. After nitrogen is used for slagging, the converter starts to rotate for deslagging. According to the difference of the slag surface height of the slag, the slag of the converter begins to be poured out within the range of 60-80 degrees, and the flow of the single branch gas supply element is controlled within 30-80 Nm3H is used as the reference value. Because the bottom blowing gas supply element is immersed under the molten iron or the inclination angle deviates from the molten iron in the pouring process, the effect of sweeping the slag surface is avoided, and the gas is wasted due to large flow. Therefore, 30 to 80Nm is used3Safe flow per hour.
The rotation angle of the converter is 0-80 degrees, and at the moment, the bottom blowing gas supply elements are all immersed under the molten steel by 30-80 Nm3Safe flow per hour. At this time, if a large amount of bottom-blowing gas is supplied, molten steel is blown out, the degree of mixing between the molten steel and the steel slag increases, and the iron loss increases. If the flow rate is less than 30Nm3And h, the gas supply element can cause blockage of the gas supply element due to the deposition of the steel slag.
When the rotation angle of the converter is more than 80 degrees, the gas supply flow of the bottom blowing gas supply element is controlled by regions, the bottom blowing gas supply element is divided into two parts, one part of the bottom blowing gas supply element is immersed in the molten steel, and the other part of the bottom blowing gas supply element is not immersed by the molten steel. For the bottom blowing gas supply element immersed by the molten steel, controlling the single-branch bottom blowing gas supply flow to be 30-80 Nm3H; for the bottom-blowing gas supply element which is not immersed by the molten steel, the flow rate of the single-branch bottom-blowing gas supply is controlled to be more than 150Nm3H is used as the reference value. The reason is that the bottom blowing gas supply element is not immersed by the molten steel, so that more steel slag can be blown to the converter mouth by the large-flow bottom blowing gas supply flow, and the pouring amount of the steel slag is increased; for the bottom-blowing gas supply element immersed in the molten steel, if the bottom-blowing gas supply flow is carried out at a large flow, the mixing degree of the molten steel and the steel slag is increased, and iron in the molten steel enters the steel slag, so that the loss of the iron is caused.
In order to achieve that the gas of the bottom blowing gas supply element sweeps the dephosphorized slag to gush out to the furnace mouth more, the thickness of the slag splashing layer above the bottom blowing gas supply element is not more than 50 mm. In the prior art, the requirement of the thickness of the slag splashing layer is to strengthen the ventilation in the smelting process of the converter so as to achieve the aim of strengthening the stirring of a molten pool. The requirement for the height of the slag layer is here for protection of the kinetic energy of the gas, in order to purge the slag.
Illustratively, as shown in FIG. 1, the rotary furnace is rotated at an angle of inclination of 95 °. The bottom blowing gas supply elements 4 are distributed at the bottom of the converter shell 1 and are uniformly distributed along the central line of the rotary trunnion 5 of the converter in a rectangular distribution mode and an annular distribution mode, wherein the annular distribution mode is shown in figure 3, and the rectangular distribution mode is shown in figure 4. Most of the bottom-blown inert gas is distributed in an annular mode, and most of the bottom-blown oxygen is distributed in a rectangular mode. The bottom blowing oxygen is determined according to the smelting process, and the converter does not want the bottom blowing gas supply elements to be immersed in molten steel in the dumping process, because the flow of the bottom blowing gas supply elements in the bottom blowing oxygen bottom process is too large, and the bottom blowing gas supply elements are immersed and dissolved to cause the damage of the bottom of the converter. For a plurality of gas supply elements, the annular distribution is relatively distributed, while the rectangular distribution has half of two rows, which are relatively concentrated. When the dephosphorization period smelting is finished, the foamed dephosphorization slag 2 overflows from the furnace mouth and is mixed with the semisteel molten steel in the converter. After dephosphorization smelting is finished, slag foams, the size of the slag is increased, and the slag easily overflows from a furnace mouth and is not easy to pour. The flow regulation range of the bottom blowing air supply element is 20-200 Nm3The adjustment range of the air supply pressure is 0.2-1.5 MPa. The pouring of the dephosphorized slag is realized by means of sweeping of bottom blowing gas, high flow is realized by high pressure, and kinetic energy of the gas is large when the flow is large and the pressure is high, so that the dephosphorized slag is favorably swept, and more slag can be poured.
In order to facilitate smooth pouring of the slag in the dephosphorization period, the following operations are adopted:
step 1: and (3) carrying out nitrogen slagging after the smelting in the dephosphorization period is finished and before the converter tilts, wherein the nitrogen process comprises the following steps: the nitrogen blowing pressure is more than 0.7MPa, the continuous nitrogen blowing time is more than 120s and more than t and more than 30s, the nitrogen blowing gun position is more than 2.5m, and the sliding gun operation is adopted;
step 2: after the smelting in the dephosphorization period is finished (oxygen blowing is finished and the oxygen lance is lifted), the gas flow of the single-branch bottom blowing is reduced, at the moment, the converter starts to rotate, and the rotation range of the tilting angle alpha of the converter is more than or equal to 0 degree and less than or equal to 180 degrees. The converter tilting angle and the air supply flow control of the bottom blowing air supply element are in the following relation:
when tiltingThe angle is more than 80 degrees, alpha is more than or equal to 0 degree, bottom blowing gas is uniformly distributed by the bottom blowing gas supply element, and the single-branch bottom blowing gas supply flow is controlled to be 30-80 Nm3/h；
When the tilting angle alpha is more than or equal to 80 degrees, the air supply flow of the bottom blowing air supply element is controlled by regions, and for the bottom blowing air supply element immersed by the molten steel, the single-branch bottom blowing air supply flow is controlled to be 30-80 Nm3H; for the bottom-blowing gas supply element which is not immersed by the molten steel, the flow rate of the single-branch bottom-blowing gas supply is controlled to be more than 150Nm3/h；
When the tilting angle is less than 80 degrees, the converter rotates towards the central shaft direction of the converter after slag dumping is finished, the bottom blowing gas supply element distributes gas evenly, and the single-branch bottom blowing gas supply flow is controlled to be 30-80 Nm3/h。
Example 1:
in a 120t top-bottom combined blown converter, bottom-bottom blowing gas supply elements are annularly distributed and divided into six branches, the gas supply elements are annularly and uniformly distributed in six rings, a double-slag residue remaining process is adopted, and the molten iron loading amount is 115 t. Wherein, the dephosphorization smelting period, the oxygen blowing time is 360s, and the oxygen flow is 13800-17000 Nm3The flow rate of the single-branch bottom blowing gas during oxygen blowing is 170-220 Nm3H is used as the reference value. When the dephosphorization period is finished, the foamed dephosphorization slag overflows from the furnace mouth, the oxygen lance is rapidly lifted, and meanwhile, the single-branch bottom blowing gas supply flow is switched to 40-60 Nm3And h, closing the oxygen after the oxygen lance is lifted to an oxygen opening point, opening the nitrogen and descending the lance to continuously knock off slag, sliding the lance to knock off the slag, wherein the position of the slag knocking lance is 2500-3500 mm, the slag knocking pressure is 1.2Mpa, and the slag knocking time is 100 s. And after the slag removing, carrying out furnace shaking and slag pouring.
As shown in Table 1, after the completion of the slag removal, the converter started to rotate. When the rotation angle of the converter is 0-80 degrees, the six bottom blowing gas supply pipelines are immersed by the molten steel at the flow rate of 45Nm3T.min; the converter continues to rotate, the rotation angle of the converter is larger than 80 degrees, and the flow rate of a bottom blowing pipeline which is not immersed by the molten steel is set to be 220Nm3At/t min, the flow rate of the bottom-blowing pipe submerged in the molten steel was set to 45Nm3T.min, starting to pour slag at the moment, and keeping the pouring time for 2 min. And after the slag pouring is finished, the slag pouring amount is 8t, and the converter rotates towards the direction of the central shaft of the converter to perform the next operation of converter smelting.
Table 1: rotating inclination angle and flow control of annular uniform converter
Note:
-a bottom blowing line submerged in the molten steel;
a bottom blowing line immersed in the molten steel.
Comparative example
The dephosphorization slag in the dephosphorization period of the existing converter double-slag process is poured in a direct pouring mode. Taking a 120t top-bottom combined blown converter as an example, the control process is as follows:
(1) after the dephosphorization period is finished, the gas flow of the single branch bottom blowing is switched to 60Nm3And h, opening nitrogen, closing oxygen, fixing a gun position for slagging, fixing the slagging gun position to be 2.5m, setting the slagging pressure to be 0.7-0.8 Mpa, and setting the slagging time to be 60 s. And after the slag removing, carrying out furnace shaking and slag pouring.
(2) After the slagging is finished, the converter is rotated to directly dump the dephosphorized slag, and the gas flow of each branch component of the bottom blowing is 60Nm3/h。
In the process in the prior art, the deslagging time lasts 3-4 min, the deslagging amount is 5-6 t, the deslagging time of the process is 2min, the deslagging amount is 8t, the deslagging time is shortened by nearly 50%, and the deslagging amount is improved by 30-60%.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.
Claims (7)
1. A method for improving pouring amount of dephosphorization residues in a converter double-slag process dephosphorization period is characterized by comprising the following steps:
step 1: after the smelting in the dephosphorization period is finished and before the converter tilts, nitrogen is firstly used for slagging;
step 2: rotating the converter to dump the dephosphorized slag after slagging in the dephosphorizing period is finished, and controlling the air supply flow of the bottom blowing air supply element to change along with the tilting angle alpha of the converter;
the nitrogen blowing and slag removing adopt sliding guns, the gun positions are not fixed, and the retention time of one gun position is not more than 30 s;
in the step 2, reducing the flow of the single-branch bottom blowing gas after the smelting in the dephosphorization period is finished;
in the step 2, when the tilting angle is more than 80 degrees and alpha is more than or equal to 0 degrees, the bottom blowing gas supply element distributes the bottom blowing gas evenly, and the single-branch bottom blowing gas supply flow is controlled to be 30-80 Nm3H; when the tilting angle alpha is more than or equal to 80 degrees, the bottom blowing gas supply element adopts the regional control, the bottom blowing gas supply element immersed by the molten steel controls the single-branch bottom blowing gas supply flow to be 30-80 Nm3H; the bottom-blowing gas supply element which is not immersed by the molten steel controls the single-branch bottom-blowing gas supply flow to be more than 150Nm3/h；
The thickness of the slag splashing layer above the bottom blowing gas supply element is less than or equal to 50 mm.
2. The method for improving the pouring amount of the dephosphorization residues in the dephosphorization period of the converter double-slag process according to claim 1, wherein the control process in the nitrogen slagging in the step 1 is as follows: the nitrogen blowing pressure is more than 0.7MPa, the continuous nitrogen blowing time is more than 120s and more than t and more than 30s, and the nitrogen blowing gun position is more than 2.5 m.
3. The method for increasing the pouring amount of the dephosphorization residues in the dephosphorization period of the converter dual-slag process according to claim 1, wherein the variation range of the tilting angle α is 0 ° or more and 180 ° or less.
4. The method for improving the pouring amount of the dephosphorization residues in the dephosphorization period of the converter double-slag process according to claim 1, wherein the flow regulation range of the bottom blowing gas supply element is 20-200 Nm3/h。
5. The method for improving the pouring amount of the dephosphorization residues in the converter double-slag process dephosphorization period according to claim 1, wherein the adjusting range of the air supply pressure of the bottom blowing air supply element is 0.2-1.5 MPa.
6. The method for improving the pouring amount of the dephosphorization residues in the dephosphorization period of the converter double-slag process according to any one of claims 1 to 5, wherein the number of bottom blowing gas supply elements is more than or equal to 2.
7. The method for improving the pouring amount of the dephosphorization residues in the converter dual-slag process dephosphorization period according to claim 1, wherein the bottom-blown gas supply elements are uniformly distributed along the center line of the rotary trunnion of the converter in a circular uniform distribution or rectangular uniform distribution.
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| CN111944945A (en) * | 2020-07-31 | 2020-11-17 | 邯郸钢铁集团有限责任公司 | Direct tapping method for converter without turning up converter |
| CN113234895B (en) * | 2021-04-15 | 2022-10-21 | 攀钢集团西昌钢钒有限公司 | Surging slag skimming system and airflow adjusting device and method thereof |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59185719A (en) * | 1983-04-04 | 1984-10-22 | Kawasaki Steel Corp | Slag-off method in converter having bottom blowing installation |
| JPH06248322A (en) * | 1993-02-22 | 1994-09-06 | Sumitomo Metal Ind Ltd | Method for discharging slag in ladle |
| CN105603146A (en) * | 2016-02-25 | 2016-05-25 | 钢铁研究总院 | Converter bottom blowing element air-supply method conducting grouping, timing and rotary switching according to intensity |
| CN109097523A (en) * | 2018-08-31 | 2018-12-28 | 钢铁研究总院 | A kind of double slag process smelting process |
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- 2020-03-31 CN CN202010246787.5A patent/CN111254253B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59185719A (en) * | 1983-04-04 | 1984-10-22 | Kawasaki Steel Corp | Slag-off method in converter having bottom blowing installation |
| JPH06248322A (en) * | 1993-02-22 | 1994-09-06 | Sumitomo Metal Ind Ltd | Method for discharging slag in ladle |
| CN105603146A (en) * | 2016-02-25 | 2016-05-25 | 钢铁研究总院 | Converter bottom blowing element air-supply method conducting grouping, timing and rotary switching according to intensity |
| CN109097523A (en) * | 2018-08-31 | 2018-12-28 | 钢铁研究总院 | A kind of double slag process smelting process |
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