KR101257740B1 - Refining method for hot metal containing high-silicon concentration - Google Patents

Abstract

The present invention comprises the steps of charging a high-silicon molten iron in the converter to perform the first blow, and when the concentration of the silicon in the molten iron during the first blow to the set concentration, the first blow is completed, the first blowed molten iron converter First tapping through the tap of the tap, recharging the molten iron from the first tapping step into an empty converter, and performing a second blow on the molten iron reloaded into the converter in the reloading step And it relates to a method of refining molten iron molten iron including the step of tapping the molten iron is refined through the second scouring step, through the tap of the converter.

Description

REFINING METHOD FOR HOT METAL CONTAINING HIGH-SILICON CONCENTRATION}

The present invention relates to a method for refining high silicon molten iron which can refine a high silicon molten iron in a converter having a silicon content higher than that of a general molten iron.

In general, the steelmaking process is to prepare molten iron by melting iron ore in the blast furnace, and then to perform molten iron through a first refining process to remove impurities in the molten iron by sequentially performing desulfurization, delineation, decarburization, and deoxidation. do. After the impurities are removed, the molten steel is moved to the continuous casting process when the fine constituents in the molten steel are adjusted through the secondary refining process. After that, the semi-finished product is formed through a continuous casting process, and the final product is manufactured into a product to be finally obtained through a final molding process such as rolling.

The converter is a facility for removing impurities from molten iron produced in the blast furnace, and the Tallinn converter is a facility for manufacturing ultra-low grade steel by lowering the phosphorus content in the molten iron as much as possible. In addition, the decarburization furnace is a facility used to lower the concentration of carbon in the molten iron. The converter operation may be carried out in a manner in which the subsidiary material or gas is blown into the molten iron and the molten iron is stirred to promote the reaction between the subsidiary material and the gas and the molten iron.

It is an object of the present invention to provide a method for refining molten molten iron, which enables molten steel with high silicon content to be refined in a converter to reduce molten steel during refining.

According to an embodiment of the present invention for realizing the above object, the method of refining molten iron molten iron, the step of charging the molten molten silicon in the converter to perform a first blow, and the concentration of silicon in the molten iron during the first blow When the concentration is set to complete the first blow, the first tapping the first blown molten iron through the tapping hole of the converter, and recharging the molten iron tapping in the first tapping step into the empty converter And performing a second blow on the molten iron reloaded into the converter in the reloading step, and tapping the molten iron on which the refining is completed through the second blowing step through the tapping hole of the converter. Can be.

The silicon concentration in the molten iron in the high silicon molten iron may be characterized in that more than 0.8% by weight.

In the step of performing the first blow, it may be characterized in that the silicon concentration in the molten iron is reduced by inputting more than 8.5 tons of quicklime per ton of the high silicon molten iron.

In the first tapping step, the concentration of silicon in the molten iron is tapping may be characterized in that 0.2 ~ 0.4% by weight.

After the primary tapping is completed, the method may further include discharging the high silicon slag remaining in the converter to the outside by tilting the converter.

After the second tapping is completed, the method may further include discharging the slag remaining in the converter to the outside by tilting the converter.

The tilt angle of the converter for tapping the first blown molten iron in the first tapping step may be characterized in that the 65 ~ 75 °.

The tilt angle of the converter for tapping the molten iron completed in the second tapping step may be characterized in that the 65 ~ 75 °.

According to the method for refining high silicon molten iron according to the present invention constituted as described above, the molten iron having a high content of silicon, which has been previously discarded, may be refined in a converter to be manufactured as molten steel, thereby improving productivity. In addition, it is possible to reduce the risk of slipping that may occur during the refining of high-silicon molten iron has the effect of improving the work efficiency.

1 is a conceptual view briefly showing a turning process during a steelmaking process related to the present invention.
2 is a flowchart showing a method of refining high silicon molten iron in accordance with an embodiment of the present invention in order.
FIG. 3 is a conceptual diagram schematically illustrating a method of refining molten iron of FIG. 2 in order.
4 is a conceptual view schematically showing a method for refining molten iron of silicon according to another embodiment of the present invention in order.

Hereinafter, a method of refining molten molten silicon in accordance with a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the present specification, the same or similar reference numerals are given to different embodiments in the same or similar configurations.

1 is a conceptual view briefly showing a turning process during a steelmaking process related to the present invention.

Referring to the drawings, in general, the converter 10 is used for tapping by receiving the molten iron (M) in the form of dissolved iron ore to perform the operation of adjusting the content of a certain element in the molten iron. The molten iron M which has been refined is tapped through the tapping hole 11. When the molten iron M is charged into the converter 10, the molten iron M inserted by inserting a lance 20 into which the gas can be blown from the upper part is erected upright. The gas is blown to the top of the. At this time, a deodorant tuyere which can blow gas can also be installed in the lower portion of the converter 10. That is, at the upper portion of the converter 10, gas is blown into the upper portion of the molten iron via the lance 20, and argon gas is injected into the molten iron through the lower portion of the molten iron wire M I accept it. While blowing the molten iron through the gas injection in the molten iron (M) it is possible to promote the refining reaction in the molten iron (M) by adding a secondary raw material from the top. Thus, slag is formed in the upper part of the molten iron (M) refined due to the addition of oxygen and argon gas and subsidiary materials, and after removing the slag, the molten iron (M) is tapped and transferred to the tapping hole (11) for subsequent processing. do.

FIG. 2 is a flowchart illustrating a method of refining high silicon molten iron in accordance with an embodiment of the present invention, and FIG. 3 is a conceptual view schematically illustrating a method of refining high silicon molten iron in FIG.

Referring to FIG. 2, the refining of the high silicon molten iron may be performed when the concentration of silicon in the molten iron is increased due to the blast furnace initial operation or the aging problem. As shown in FIG. 3, after charging the high-silicon molten iron into the converter 10, the oxygen gas is injected from the upper portion of the molten iron through the lance 20, the subsidiary materials, etc. are introduced into the molten iron, and then the molten iron is stirred. Perform the first blow to adjust (S10).

The silicon concentration in the molten iron of the high silicon molten iron which performs the 1st blow is 0.8 weight% or more.

It is preferable to use quicklime as a subsidiary material introduced into the high silicon molten iron during the first blow. In this case, the amount of quicklime injected into the high silicon molten iron is preferably 8.5 tons or more according to the silicon concentration in the high silicon molten iron per ton of molten iron. Specifically, when the silicon concentration in the high silicon molten iron is 0.8% by weight, the amount of quicklime added is preferably 8.5 ton per ton of molten iron. If the silicon concentration in the high silicon molten iron is 0.8% by weight, if the amount of quicklime injected is less than 8.5 tons per ton of molten iron, the first blown effect may be reduced and the silicon concentration in the high silicon molten iron may not be reduced to a predetermined value. In addition, if it exceeds this, the blowing effect compared to the amount of silicon in the molten iron may be insignificant.

High-silicon molten iron is a molten iron with a silicon concentration of 0.8 wt% or more in molten iron, so when the first high-silicon molten iron with a molten silicon concentration of more than 0.8 wt% is added, the amount of quicklime added per ton of molten iron exceeds 8.5 tons It is necessary to do

For example, when the silicon concentration in a high silicon molten iron is 2.0 weight%, it is preferable to introduce | pour 12.5 tons of quicklime per ton of molten iron, and perform a 1st blow.

When the concentration of the silicon in the molten iron by the first blow is set to the set concentration, the first blow is completed, and the first blown molten iron M1 is first tapped out of the converter 10 (S20). At this time, the molten iron concentration in the molten iron at the time of completing the first blow is 0.2 to 0.4% by weight. The reason for adjusting the silicon concentration to 0.2 to 0.4% by weight at the time of completion of the first blow is that it is easy to adjust the silicon concentration through refining in the converter 10 during the second blow, which is carried out in the future, and there is no risk of slipping. Because you can operate. Sloping phenomenon is easy to occur when the decarburization reaction occurs suddenly in the initial converter, as in the present invention, when the silicon concentration is adjusted to 0.2 to 0.4% by weight at the completion of the first blow-off, de-silification reaction occurs before decarburization reaction and decarburization occurs. Since the first blow is completed just before the reaction occurs, it is possible to fundamentally reduce the slope phenomenon generally occurring at the beginning of refining.

When tapping the first blown molten iron M1 from the converter 10, the tapping hole 11 formed on the outer surface of the converter 10 is opened and the converter 10 is tilted, and as shown in the drawing, only the molten iron located in the lower part is moved outward. Tapping Only the molten iron M1 is completely tapped out of the converter 10, and only the high silicon slag S1 positioned at the upper end of the molten iron M1 remains in the converter 10 to complete the primary tapping. It is also possible to incite the converter before the first tapping and allow time for the first tapping while the reaction of the slag and molten iron is settled down.

When the first blow, the converter 10 is upright, with the inlet facing upward, and the tilt angle of the converter 10 when tapping the molten iron M1 after the first blow is completed is the state in which the converter 10 is erected. It is preferable that it is 65-75 degree on the basis of. If the tilt angle of the converter 10 is less than 65 °, the molten iron M1 inside the converter 10 may not be completely tapped through the tap hole 11, and the tilt angle of the converter 10 exceeds 75 °. If there is a risk that the high silicon slag (S1) located on the molten iron (M1) or the molten iron (M1) through the opening of the converter 10 of the open shape formed on the converter 10 there is a risk of flowing out.

If the first molten molten iron is not discharged through the tapping hole 11 and the slag formed at the upper end after refining is first removed through the converter 10 inlet, the tilt angle of the converter 10 becomes excessive. (10) The molten iron M1 may flow out through the inlet. In addition, since the high silicon slag (S1) at the initial stage of refining does not have sufficient fluidity and the temperature easily falls, it is difficult to remove the high silicon slag (S1).

The molten iron tapping out of the converter 10 through the first tapping is reloaded into the empty converter 10 (S30). In this case, the empty converter 10 used to reload the molten iron may be a new converter 10 that has not been operated. The reloaded molten iron is molten iron M1 which does not include high silicon slag S1 after completion of the first blow.

After recharging the molten iron M1 to which the first blow is completed in the empty converter 10, the gas is blown through the lance 20 by raising the converter 10 upright, and the secondary raw material is injected into the molten iron. 2 blows (S40). While the second blowing is performed, the components in the molten iron can be adjusted to the finally set concentration. If the first silicon is not subjected to the second smelting with the molten iron in which the silicon concentration is controlled, and the high silicon molten iron is continuously refined in the same converter 10, a large amount of quicklime must be added to match the basicity of the molten iron. At this time, depending on the concentration of silicon may occur a situation in which the quick lime exceeding the capacity of the converter 10 may occur, the operation may be impossible. In addition, the molten iron thus worked may not be used and may be discarded. In addition, due to the slag generated during refining due to the high silicon concentration, carbon monoxide gas generated in the molten iron is not discharged through the slag and accumulated in the lower slag. When the accumulation amount of carbon monoxide in the lower slag is excessive, eventually the slag is exploded and drilled out to generate a slope phenomenon to eject the slag to the outside of the converter 10, which causes a dangerous situation during operation.

When the second blow is completed, the refined molten iron (M2) is tapped second through the tap hole 11 of the converter 10 (S50). In the second blow, the converter 10 is in an upright state with the inlet facing upward, and the tilt angle of the converter 10 when tapping the molten iron M2 after the second blow is completed is the state in which the converter 10 is erected. It is preferable that it is 65-75 degree on the basis of. If the tilt angle of the converter 10 is less than 65 °, the molten iron M2 inside the converter 10 may not be completely tapped through the tap hole 11, and the tilt angle of the converter 10 exceeds 75 °. If there is a risk that the slag (S2) located at the top of the molten iron (M2) or molten iron (M2) through the inlet of the open converter 10 formed in the upper portion of the converter 10 there is a risk of flowing out.

In this regard, in the case of refining a 340 ton high silicon molten iron in a converter, the quicklime input criteria according to the concentration of silicon in the molten iron during the first and second blows are shown in Table 1 below.

ship chartering Si (weight%) First blown quicklime ( Ton ) 2nd quicklime quicklime ( Ton ) 0.8 8.5 5.0 0.9 10.0 4.5 1.0 11.0 4.0 1.1 12.5 3.5 1.2 13.5 3.5 1.3 15.0 3.5 1.4 15.0 3.0 1.5 16.0 2.5 1.6 17.5 2.0 1.7 19.0 2.0 1.8 20.0 2.0 1.9 21.5 2.0 2.0 22.5 1.5

As shown in Table 1, for example, when the first high-silicon molten iron containing 0.8% by weight of silicon is blown, the quicklime injected into the molten iron is 8.5 tons per ton of molten iron, and the second after the first blow is completed. The quicklime injected into the molten iron in the blowing process is preferably 5 ton per ton of molten iron. In the case of the first drilling of the high-silicon molten iron containing 2.0% by weight of silicon, the quicklime injected into the molten iron is 22.5 tons per ton of molten iron, and the quicklime injected into the molten iron in the second refining process after completion of the first It is preferable that it is 1.5 tons per ton of molten iron | metal. At this time, the amount of quicklime added during the first blow may be set to an amount capable of reducing the silicon concentration in the molten iron at the end of the first blow to 0.2 ~ 0.4% by weight.

In the case of refining the 340 ton high silicon molten iron, the actual internal converter capacity is about 500 to 700 tons, and the inside of the converter is filled with high silicon molten iron including slag on the upper portion of the 340 ton molten iron. The reason for operating only about 340 tons of molten iron from about 500 to 700 tons is that the slag volume is very large. Since slag is about 10 times larger than its volume, it can fill the inside of the converter even if the converter has a capacity of 500 to 700 tons and 340 tons of molten iron and slag. Therefore, in this case, if several tons of quicklime is additionally added as a feedstock, it is impossible to add more than a certain amount of quicklime, since a slope phenomenon may occur in the converter due to the reaction in the molten iron and an accident may occur during operation. For example, in order to refine 340 tons of high silicon molten iron having a silicon concentration of 2.0 wt% in the converter 10 as shown in Table 1, quicklime exceeding 22.5 tons should be added in the case of the first blown. In this case, the amount of molten iron and injected quicklime may not be enough to fill the interior of the 340 ton converter 10, and the refining operation may not be possible because the amount of quicklime is excessively high and the risk of slipping is very large.

Therefore, the upper limit of the silicon concentration in the high silicon molten iron that can be processed depending on the capacity of the converter to be operated may be fluid.

The molten iron (M2) refined through the second tapping may be transferred to the subsequent process.

4 is a conceptual view schematically showing a method for refining molten iron of silicon according to another embodiment of the present invention in order.

Referring to the drawings, the first blown high silicon molten iron M1 is first tapped through the tap hole 11 of the converter 10. After that, it is possible to tilt the converter 10 at an angle exceeding 75 ° in order to completely exclude the high silicon slag S1 remaining in the converter 10 in the converter 10. At this time, since the molten iron (M2) after tapping all, even if the converter 10 is tilted at an angle exceeding 75 °, there is no risk of external leakage of the molten iron (M2), it is very easy to remove the high silicon slag (S1) Can be.

The first blowing molten iron M2 tapping out of the converter 10 through the first tapping may be reloaded into the converter 10 used for the first blow. At this time, since the high silicon slag (S1) is already completely excluded to the outside of the converter 10, it is possible to reuse the converter 10 used for the first blow. The reloaded molten iron is secondary tapping through the tap hole 11 of the converter 10 after completing the adjustment of the components to the concentration set through the second blow.

When the molten molten iron M2 is completely discharged through the tap hole 11, the slag S2 positioned on the upper molten iron M2 remains in the converter 10. Then, to reuse the converter 10, the converter 10 is tilted at an angle exceeding 75 ° to completely exclude the slag S2 to the outside of the converter 10 through the converter 10 inlet. In this case, since the molten iron (M2) is all discharged inside the converter (10), there is little restriction in tilting the converter (10) and the risk of work is lowered, and the efficiency of the slag (S2) exclusion work can be improved.

According to the method for refining high silicon molten iron according to the present invention configured as described above, since molten iron having a high content of silicon can be refined in a converter, there is an effect of improving productivity. In addition, there is an effect that can reduce the risk of slopes that may occur during the refining of high-silicon molten iron.

Such a method of refining molten molten iron is not limited to the configuration and operation of the embodiments described above. The above embodiments may be configured such that various modifications may be made by selectively combining all or part of the embodiments.

10: Converter 11: Slot
20: Lance S1: High Silicon Slag
S2: slag M1: first blow finished molten iron
M2: 2nd Recruitment Charter

Claims (8)

Charging a high silicon molten iron into a converter to perform a first blown;
When the concentration of the silicon in the molten iron during the first blown 0.8% by weight completes the first blow, and the first tapping the molten molten molten iron through the tap of the converter;
Recharging the molten iron from the first tapping step into an empty converter;
Performing a second blow on the molten iron reloaded into the converter in the reloading step; And
And a second tapping of the molten iron having been refined through the second scouring step, through the tap hole of the converter.
In the step of performing the first blow, it is characterized in that the silicon concentration in the molten iron is reduced by inputting more than 8.5 tons of quicklime per ton of high-silicon molten iron, high silicon molten iron refining method.
delete delete The method according to claim 1,
In the first tapping step, the concentration of silicon in the molten iron is carried out by performing the first blown, characterized in that 0.2 to 0.4% by weight, high silicon molten iron refining method.
The method according to claim 1,
After the primary tapping is completed, the step of tilting the converter further comprises the step of discharging the high-silicon slag remaining in the converter to the outside, removing the high silicon molten iron.
The method according to claim 1,
After the second tapping is completed, further comprising the step of discharging the slag remaining in the converter to the outside by tilting the converter, the high silicon molten iron refining method.
The method according to claim 1,
The tilting angle of the converter for tapping the first blown molten iron in the first tapping step is 65 ~ 75 °, refining method of high silicon molten iron.
The method according to claim 1,
The tilting angle of the converter for tapping the molten molten iron refined in the second tapping step is 65 ~ 75 °, high silicon molten iron refining method.

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