KR20190077861A - Method for predicting slag basicity of molten slag - Google Patents

Abstract

According to the present invention, disclosed is a method for predicting basicity of molten metal slag. According to an embodiment, the method for predicting basicity of molten metal slag comprises the following steps of: refining molten metal in an electric furnace and then measuring electric furnace end point molten metal oxygen amounts; allowing the molten metal refined in the electric furnace to flow out of the electric furnace to be transferred to a ladle furnace (LF); and deriving a basicity prediction value of the molten metal slag reaching the LF by putting the electric furnace end point molten metal oxygen amounts into the following formula 1.

Description

METHOD FOR PREDICTING SLAG BASICITY OF MOLTEN SLAG BACKGROUND OF THE INVENTION 1. Field of the Invention < RTI ID = 0.0 &

The present invention relates to a method for predicting molten steel slag basicity. More particularly, the present invention relates to a method for predicting the basicity of a molten steel slag that has arrived at an LF facility using molten steel information collected at an electric furnace end point in an electric furnace LF process.

The electric furnace means a heating furnace which generates heat to melt scrap iron and the like, and the electric furnace operation produces molten steel in an electric furnace by using scrap metal scrap. The electric furnace facility is a facility that scrapes scrap steel between electrodes and then energizes electricity to melt scrap steel using arc heat generated at this time. The molten steel which is led out from the electric furnace can be taken using a ladle. The molten steel that has been taken is moved to the Ladle Furnace (LF), where the molten steel is refined.

On the other hand, in the case of a special steel which performs aluminum (Al) deoxidation in the electric arc furnace, it is required to control the slag basicity (C / A) of molten steel reaching the ladle LF to a specific range in order to control the inclusion content do.

The background art of the present invention is disclosed in Korean Patent Registration No. 10-1504280 (published on Mar. 19, 201, entitled "Method for predicting iron oxide content in electric furnace melted slag").

According to an embodiment of the present invention, there is provided a method for predicting a slag basicity of molten steel excellent in accuracy of predicted value of slag basicity of molten steel at the time of arrival in an LF facility.

According to an embodiment of the present invention, it is possible to precisely control the amount of additive and burnt lime for controlling the slag basicity, and to provide a method for predicting the basicity of molten steel slag with excellent economy.

According to an embodiment of the present invention, there is provided a method for predicting molten steel slag basicity capable of efficient operation and capable of producing high quality molten steel.

One aspect of the present invention relates to a method for predicting molten steel slag basicity. In one embodiment, the method for predicting the basicity of molten steel slag includes the steps of refining molten steel in an electric furnace and measuring the amount of molten steel in an electric furnace end point; Feeding molten steel refined in the electric furnace to the ladle (LF); And calculating a basicity predicted value of the molten steel slag arriving at the ladle (LF) by substituting the oxygen amount of the electric furnace end point molten steel into the formula (1), wherein the predicted value of the basicity of the arrival molten steel slag Analyzing the molten steel composition and the slag composition of the electric furnace end point; Analyzing the molten steel composition arriving at the ladle; Deriving an electric furnace outlet slag amount and total aluminum oxide (Al ₂ O ₃ ) generation amount using the weight of molten steel introduced from the electric furnace and the composition of the molten steel and slag of the electric furnace end point analyzed; The amount of the electric furnace effluent slag, the total amount of aluminum oxide (Al ₂ O ₃ ) generated, the amount of burnt lime, aluminum, and flux input into the molten steel introduced in the electric furnace, and the amount of flux supplied to the molten steel reaching the ladle (LF) Deriving a calculated basicity value of the molten steel slag arriving at the ladle furnace (LF) using the deoxidizer input amount; And deriving a correlation equation between a basicity calculated value of the molten steel slag arriving at the derived ladle furnace (LF) and a molten steel oxygen amount of the electric furnace end point:

[Formula 1]

(LF) Arrival slag basicity (C / A) = ((-6 * 10 ^-6 ) * (The amount of oxygen in the molten steel at the end point of the electric furnace (ppm)) ² ) + (0.0003 * (the amount of oxygen in the molten steel at the end point of the electric furnace (ppm)) + 2.1482

In one embodiment, the calculated basicity of the molten steel slag arriving at the ladle (LF) can be derived by the following equation:

[Formula 2]

(In the formula 2, the slag Ca0 _{furnace end position,} and the end point of calcium (CaO) content (% by weight) oxidation of the slag in electric and the slag Al ₂ O _{3 an electric furnace end point,} the aluminum oxide of the end slag into electricity (Al ₂ O ₃ ) content (% by weight), and the total flux input amount is a flux input amount (kg) input to molten steel introduced into an electric furnace and ladle furnace, and k is a slag basicity correction factor, 1.0 to 1.5. .

In one embodiment, the amount of electric furnace effluent slag may be derived from Equation 3:

[Formula 3]

_Wherein the [% P] _{LF arrival} is a (P) content (wt%) in the molten steel arriving at the ladle, and the [% P] _{electric furnace end point} is the molten steel P) content (% by weight), and the [% P ₂ O ₅ ] _{electric furnace end point} is a phosphorus pentoxide (P ₂ O ₅ ) content (% by weight) in the molten steel slag of the electric _{furnace end} point.

In one embodiment, the total aluminum oxide yield can be derived by the following equation:

[Formula 4]

In one embodiment, the amount of oxygen deoxidized aluminum (Al) in the electric furnace end point molten steel is derived by the following equation 5, and the amount of aluminum oxide deoxidized aluminum (Al) in the electric furnace end point slag is derived by the following formula 6, The amount of excess aluminum (Al) can be derived by the following equation 7:

[Formula 5]

Oxygen deoxidized aluminum (Al) amount in the electric furnace end point molten steel (kg) = Oxygen amount (% by weight) in the end point steel of the electric furnace * Weight of molten steel in the electric furnace (kg) * 0.011

[Formula 6]

(Kg) = amount of steel slag discharged into electric furnace (kg) * content of iron oxide (FeO) in electric furnace end point slag (% by weight) * 0.0025

[Equation 7]

Al (A1) (kg) + (Al) input amount (kg) + (deacidizer input amount (kg) * 0.5)) - (Oxygen deoxidized aluminum (Al) the amount (kg)) - (the end point of the molten steel into an electric oxygen deoxidized aluminum (Al), the amount (kg)) - (tapping the molten steel into an electric weight (kg) * ([% Al ] LF _arrival / 100))

(In the above formula 7, the [% Al] _{LF arrival} is the aluminum content (wt%) in the molten steel arriving at the ladle.

When the slag basicity prediction method of the present invention is applied, it is possible to predict the slag basicity of the molten steel at the time of arriving at the electric furnace LF facility by using the molten steel information collected at the electric furnace end point, It is excellent in accuracy, can control precisely the amount of additive and quicklime to control slag basicity, is economical, can operate efficiently, and can produce high quality molten steel.

FIG. 1 shows a method for predicting the basicity of molten steel slag according to one embodiment of the present invention.
2 is a graph showing a predicted value of the basicity of the arrival molten steel slag according to the amount of oxygen at the end point of the electric furnace.
3 is a graph showing the relationship between the predicted basicity of the molten steel slag arriving at the ladle furnace LF and the actual ladle furnace slag basicity (C / A) measured at the actual ladle furnace (LF).

Hereinafter, the present invention will be described in detail. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to be exemplary, self-explanatory, allowing for equivalent explanations of the present invention.

Molten steel Slag  Method of predicting basicity

One aspect of the present invention relates to a method for predicting molten steel slag basicity. In one embodiment, the method for predicting the basicity of molten steel slag includes the steps of: (S10) measuring an oxygen end point of molten steel in an electric furnace; (S20) transfer to the ladle; And (S30) deriving a basicity predicted value of the arrival molten steel slag into the ladle. More specifically, the method for predicting the basicity of molten steel slag includes the steps of: (S10) refining molten steel in an electric furnace and measuring the amount of molten steel at an electric furnace end point; (S20) feeding molten steel refined in the electric furnace to the ladle (LF); And (S30) substituting the oxygen amount of the molten steel at the end point of the electric furnace into the formula (1) to derive a predicted value of the basicity of the molten steel slag arriving at the ladle (LF).

Hereinafter, the molten steel slag basicity predicting method will be described step by step.

(S10) Electric furnace end point Molten steel  The oxygen measurement step

This step refines the molten steel in the electric furnace, And measuring the amount of oxygen in the molten steel at the end point of the electric furnace immediately before the molten steel is introduced into the electric furnace.

(S20) Ladle  Transfer stage

In this step, molten steel refined in the electric furnace is introduced and transferred to the ladle (LF).

(S30) Ladle  arrive Molten steel Of slag  basicity Predicted value  Derivation step

In this step, the predicted value of the basicity of the molten steel slag arriving at the ladle (LF) is derived by substituting the oxygen amount of the molten steel at the end point of the electric furnace into the following equation (1).

[Formula 1]

(LF) Arrival slag basicity (C / A) = ((-6 * 10 ^-6 ) * (The amount of oxygen in the molten steel at the end point of the electric furnace (ppm)) ² ) + (0.0003 * (the amount of oxygen in the molten steel at the end point of the electric furnace (ppm)) + 2.1482

At the point of arrival of the ladle (LF), the additive material is put in, the temperature is raised for about 15 minutes, and then the temperature is measured and sampled. At this time, molten steel and slag are taken together to analyze the components of molten steel and slag. The analysis of the molten steel samples taken in the arrival ladle is completed in about 7 to 10 minutes, while the analysis of the slag samples is completed in about 20 to 30 minutes, resulting in a difference in analysis time.

On the other hand, metal aluminum (Al) is added to molten steel for electric arc furnace based on the result of analysis of aluminum (Al) content among molten steel sample components of the collected electric furnace end point, and a part of the charged aluminum is oxidized and aluminum oxide ₂ O ₃ ), and the slag basicity (C / A) is lowered. Therefore, calcium oxide (CaO) is added to control the slag basicity.

However, due to the difference in analysis time between the molten steel sample and the slag sample, it is difficult to calculate the amount of the fresh slag from the initial slag sample without confirming the basicity of the incoming slag, Thereby causing a deviation of the basicity.

However, when the basicity of the molten steel slag is predicted using the oxygen end point of the electric furnace end point according to the above formula 1, the accuracy of the predicted value is excellent, and the analysis of the molten steel slag component at the time of arrival to the ladle is not performed, It is possible to accurately predict the amount of burnt lime for slag, thereby minimizing the slag basicity deviation and producing high quality molten steel.

On the other hand, the relational expression between the molten steel oxygen amount at the end point of the electric furnace and the predicted basicity of the arrival molten steel slag to the ladle is as follows: molten steel and slag information of the electric furnace end point, molten steel information furnished by electric furnace, arrival molten steel information by ladle, Can be derived using the information of.

In one embodiment, the basicity predicted value of the arrival molten steel slag to the ladle of the formula (1) is (S101) analyzing the molten steel composition and the slag composition of the electric furnace end point; (S102) analyzing the molten steel composition arriving at the ladle; (S103) deriving the weight of the molten steel and is tapped from the electric furnace, the analysis by the electricity from the composition of the molten steel and slag in the destination, the amount of slag outflow and the total aluminum oxide into an electric (Al ₂ O ₃₎ amount; (S104) to the calcium oxide, aluminum and flux (basic flux) input, and (LF) in the ladle is in the electrical outlet slag volume, a total of aluminum oxide (Al ₂ O ₃₎ amount and, added to the molten steel tapped from the electric furnace Deriving a calculated basicity value of the molten steel slag arriving at the ladle furnace (LF) by using the input amount of the flux (basic flux) and the deoxidizer (slag deoxidizer) charged in the arrived molten steel; And (S105) deriving a correlation equation between the calculated basicity value of the molten steel slag arriving at the ladle furnace LF and the molten steel oxygen amount of the electric furnace end point.

(FeO), calcium oxide (CaO), and calcium oxide (CaO) from the slag composition of the electric furnace end point by analyzing the contents (weight% The content (% by weight) of aluminum oxide (Al ₂ O ₃ ) and phosphorus pentoxide (P ₂ O ₅ ) can be analyzed. In addition, the content (weight%) of the component (P) and aluminum (Al) in the composition of the molten steel can be analyzed with the ladle.

In one embodiment, the calculated basicity of the molten steel slag arriving at the ladle (LF) can be derived by the following equation:

[Formula 2]

(In the formula 2, the slag Ca0 _{furnace end position,} and the end point of calcium (CaO) content (% by weight) oxidation of the slag in electric and the slag Al ₂ O _{3 an electric furnace end point,} the aluminum oxide of the end slag into electricity (Al ₂ O ₃ ) content (% by weight), and the total flux input amount is a flux input amount (kg) input to molten steel introduced into an electric furnace and ladle furnace, and k is a slag basicity correction factor, 1.0 to 1.5. .

The slag basicity correction factor (k) is intended to accurately derive the basicity in consideration of the variables due to the amount of aluminum oxide generated in the molten steel, the amount of burnt material such as burnt lime and flux.

In one embodiment, the amount of electric furnace effluent slag may be derived from Equation 3:

[Formula 3]

_Wherein the [% P] _{LF arrival} is a (P) content (wt%) in the molten steel arriving at the ladle, and the [% P] _{electric furnace end point} is the molten steel (% By weight) of the phosphorus pentoxide (P ₂ O ₅ ) in the molten steel slag of the electric _{furnace end point} , and the [% P ₂ O ₅ ] _{electric furnace end point} is the content (% by weight).

In one embodiment, the total amount of aluminum oxide (Al ₂ O ₃ ) generated in the molten steel can be derived from Equation 4:

[Formula 4]

In one embodiment, the amount of aluminum (Al) for oxygen deoxidation in the electric furnace end point molten steel is derived by the following equation 5, and the amount of aluminum (Al) for deoxidizing iron oxide in the electric furnace end point slag is represented by the following formula 6, and the amount of excess aluminum (Al) can be derived by the following equation (7): " (7) "

[Formula 5]

Oxygen deoxidized aluminum (Al) amount in the electric furnace end point molten steel (kg) = Oxygen amount (% by weight) in the end point steel of the electric furnace * Weight of molten steel in the electric furnace (kg) * 0.011

[Formula 6]

(Kg) = amount of steel slag discharged into electric furnace (kg) * content of iron oxide (FeO) in electric furnace end point slag (% by weight) * 0.0025

[Equation 7]

Al (A1) (kg) + (Al) input amount (kg) + (deacidizer input amount (kg) * 0.5)) - (Oxygen deoxidized aluminum (Al) the amount (kg)) - (the end point of the molten steel into an electric oxygen deoxidized aluminum (Al), the amount (kg)) - (tapping the molten steel into an electric weight (kg) * ([% Al ] LF _arrival / 100))

(In the above formula 7, the [% Al] _{LF arrival} is the aluminum (Al) content (% by weight) in the molten steel arriving at the ladle.

In one embodiment, the iron oxide (FeO) content in the electric furnace end point slag can be derived from the content of iron (T_Fe) in the slag composition of the electric furnace end point analyzed above.

When the method of predicting the basicity of molten steel slag of the present invention is applied, the accuracy of the predicted value of slag basicity of molten steel at the time of arriving at the electric furnace LF facility is excellent and it is possible to precisely control the amount of additive and quicklime for controlling slag basicity, , Efficient operation is possible, and high-quality molten steel can be produced. Particularly, by estimating the LF arrival basicity before analyzing the arriving slag sample by the ladle, it is possible to reduce the slag basicity deviation by calculating and adding the amount of corrected lime of the aluminum (Al) input, thereby improving the interstices defects.

Hereinafter, the configuration and operation of the present invention will be described in more detail with reference to preferred embodiments of the present invention. It is to be understood, however, that the same is by way of illustration and example only and is not to be construed in a limiting sense.

Example

Ladle  arrive Molten steel Of slag  basicity Predicted value  deduction

The molten steel was refined in the electric furnace, and the amount of molten steel at the end point of the electric furnace, which is the point immediately before the electric furnace, was analyzed, and the molten steel composition and the slag composition of the electric furnace end point were analyzed. Then, the molten steel was introduced into the electric furnace and transferred to the ladle, and the composition of the molten steel reached the ladle furnace was analyzed.

The amount of molten steel leached from the electric furnace and the composition of molten steel and slag at the end point of the electric furnace analyzed were used to calculate the amount of slag discharged into the electric furnace and the amount of aluminum oxide (Al ₂ O ₃ ) generated. Next, the amount of the electric furnace effluent slag, the total amount of aluminum oxide (Al ₂ O ₃ ) generated, the amount of burnt lime, aluminum and flux input into the molten steel introduced in the electric furnace, and the amount of flux supplied to the molten steel Calculated values of the basicity of the molten steel slag arriving at the ladle furnace (LF) were calculated using the input flux and deoxidizer input. Next, a correlation equation between the calculated basicity value of the molten steel slag arriving at the obtained ladle furnace (LF) and the molten steel oxygen amount at the end point of the electric furnace was derived, and the following formula (1) was derived:

[Formula 1]

(LF) Arrival slag basicity (C / A) = ((-6 * 10 ^-6 ) * (The amount of oxygen in the molten steel at the end point of the electric furnace (ppm)) ² ) + (0.0003 * (the amount of oxygen in the molten steel at the end point of the electric furnace (ppm)) + 2.1482

The composition of the molten steel slag at the end point of the electric furnace was as shown in Table 1, and the oxygen content (ppm) of the electric furnace end point molten steel component, the electric furnace end point steel and the ladle arrival molten steel are shown in Table 2, The amount (kg) of the molten steel in the electric furnace and the amount of the subordinate ingredient are shown in Table 3 below.

The calculated basicity of the molten steel slag reached to the ladle LF was derived by the following formula 2:

[Formula 2]

(In the formula 2, the slag Ca0 _{furnace end position,} and the end point of calcium (CaO) content (% by weight) oxidation of the slag in electric and the slag Al ₂ O _{3 an electric furnace end point,} the aluminum oxide of the end slag into electricity (Al ₂ O ₃ ) content (% by weight), and the total flux input amount is a flux input amount (kg) input to molten steel introduced into an electric furnace and ladle furnace, and k is a slag basicity correction factor, 1.1.

At this time, the amount of slag discharged to the electric furnace was derived by the following formula 3:

[Formula 3]

_Wherein the [% P] _{LF arrival} is a (P) content (wt%) in the molten steel arriving at the ladle, and the [% P] _{electric furnace end point} is the molten steel P) content (% by weight), and the [% P ₂ O ₅ ] _{electric furnace end point} is a phosphorus pentoxide (P ₂ O ₅ ) content (% by weight) in the molten steel slag of the electric _{furnace end} point.

Therefore, the amount of slag discharged to the electric furnace according to the formula 3 was (((0.0109-0.0101) * (153888) * (2.3)) / (1.5)) * (0.0008 / 0.001) = 151kg.

The total aluminum oxide yield was derived from the following equation:

[Formula 4]

The amount of oxygen deasphalted aluminum (Al) in the above-mentioned furnace molten steel was derived by the following equation (5).

[Formula 5]

Oxygen deoxidized aluminum (Al) amount in the electric furnace end point molten steel (kg) = Oxygen amount (% by weight) in the end point steel of the electric furnace * Weight of molten steel in the electric furnace (kg) * 0.011

The amount of aluminum oxide deoxidized aluminum (Al) in the electric furnace end point slag was derived by the following formula (6).

[Formula 6]

(Kg) = amount of steel slag discharged into electric furnace (kg) * content of iron oxide (FeO) in electric furnace end point slag (% by weight) * 0.0025

The amount of excess aluminum (Al) was derived by the following formula (7).

[Equation 7]

Al (A1) (kg) + (Al) input amount (kg) + (deacidizer input amount (kg) * 0.5)) - (Oxygen deoxidized aluminum (Al) the amount (kg)) - (the end point of the molten steel into an electric oxygen deoxidized aluminum (Al), the amount (kg)) - (tapping the molten steel into an electric weight (kg) * ([% Al ] LF _arrival / 100))

(In the above formula 7, the [% Al] _{LF arrival} is the aluminum content (wt%) in the molten steel arriving at the ladle.

The amount of aluminum deoxidized aluminum (Al) (kg) = 0.0251 * 153888 * 0.011 = 42.5 kg in the electric furnace end point molten steel and the amount of iron oxide deoxidized aluminum in the electric furnace end point slag (kg) = 151 * 19.3 * 0.0025 = 7.3 kg (Kg) was 150 + (100 * 0.5) - 42.5 - 7.3 - (153888 * 0.034 / 100) = 97.9kg and the total aluminum production (kg) was (42.5 + 7.3 + 97.9) * 1.9 = 280.6 kg.

Therefore, the basicity calculated value of the molten steel slag arriving at the ladle LF is (1.1 * ((151 * 40.7) / 100) + 500 + (500 * 0.483) (500 * 0.334) + 151 * 4.4 / 100)))) = 1.84.

On the other hand, the predicted value of the basicity of the molten steel slag arriving at the ladle (LF) was derived by substituting the measured molten steel oxygen amount at the end point of the electric furnace into the above-mentioned formula (1).

2 is a graph showing a predicted value of the basicity of the arrival molten steel slag according to the amount of oxygen at the end point of the electric furnace. Referring to FIG. 2, it can be seen that the predicted value of the basicity of the arrival molten steel slag according to the increase in the amount of oxygen at the end point of the electric furnace has the relationship of the above-mentioned equation (1).

3 is a graph showing the relationship between the predicted basicity of molten steel slag arriving at the ladle furnace LF and the actual ladle furnace slag basicity (C / A) measured at the actual ladle furnace (LF). 3, the predicted value of the basicity of the molten steel slag reached to the ladle furnace (LF) using the electric furnace end-point oxygen amount of the equation (1) of the present invention, when compared with the basicity value of the molten steel slag arriving at the actual ladle, I was able to see that it was excellent.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (5)

Refining the molten steel in the electric furnace, and measuring the amount of molten steel in the electric furnace at the end point;
Feeding molten steel refined in the electric furnace to the ladle (LF); And
And calculating the basicity predicted value of the molten steel slag arriving at the ladle (LF) by substituting the oxygen amount of the electric furnace end point in the equation (1)
The basicity predicted value of the arrival molten steel slag to the ladle of the formula (1)
Analyzing the molten steel composition and the slag composition of the electric furnace end point;
Analyzing the molten steel composition arriving at the ladle;
Deriving an electric furnace outlet slag amount and total aluminum oxide (Al ₂ O ₃ ) generation amount using the weight of molten steel introduced from the electric furnace and the composition of the molten steel and slag of the electric furnace end point analyzed;
The amount of the electric furnace effluent slag, the total amount of aluminum oxide (Al ₂ O ₃ ) generated, the amount of burnt lime, aluminum, and flux input into the molten steel introduced in the electric furnace, and the amount of flux supplied to the molten steel reaching the ladle (LF) Deriving a calculated basicity value of the molten steel slag arriving at the ladle furnace (LF) using the deoxidizer input amount; And
And deriving a correlation equation between a basicity calculated value of the molten steel slag arriving at the derived ladle furnace (LF) and an amount of molten steel oxygen at the end point of the electric furnace, and estimating a basicity slag basicity of the molten steel slag,
[Formula 1]
(LF) Arrival slag basicity (C / A) = ((-6 * 10 ^-6 ) * (The amount of oxygen in the molten steel at the end point of the electric furnace (ppm)) ² ) + (0.0003 * (the amount of oxygen in the molten steel at the end point of the electric furnace (ppm)) + 2.1482
The method according to claim 1,
Wherein the basicity calculated value of the molten steel slag arriving at the ladle (LF) is derived by the following formula (2): <
[Formula 2]

(In the formula 2, the slag Ca0 _{furnace end position,} and the end point of calcium (CaO) content (% by weight) oxidation of the slag in electric and the slag Al ₂ O _{3 an electric furnace end point,} the aluminum oxide of the end slag into electricity (Al ₂ O ₃ ) content (% by weight), and the total flux input amount is a flux input amount (kg) input to molten steel introduced into an electric furnace and ladle furnace, and k is a slag basicity correction factor, 1.0 to 1.5. .
The method according to claim 1,
Wherein the amount of the slag discharged through the electric furnace is derived from the following equation (3): <
[Formula 3]

_Wherein the [% P] _{LF arrival} is a (P) content (wt%) in the molten steel arriving at the ladle, and the [% P] _{electric furnace end point} is the molten steel P) content (% by weight), and the [% P ₂ O ₅ ] _{electric furnace end point} is a phosphorus pentoxide (P ₂ O ₅ ) content (% by weight) in the molten steel slag of the electric _{furnace end} point.
The method according to claim 1,
Wherein the total amount of aluminum oxide generated is derived by the following formula 4:
[Formula 4]

5. The method of claim 4,
The amount of oxygen deoxidized aluminum (Al) in the above-mentioned furnace molten steel is derived by the following formula 5,
The amount of iron oxide deoxidized aluminum (Al) in the electric furnace end point slag is derived by the following formula (6)
Wherein the amount of excess aluminum (Al) is derived by the following formula (7): < EMI ID = 7.0 >
[Formula 5]
Oxygen deoxidized aluminum (Al) amount in the electric furnace end point molten steel (kg) = Oxygen amount (% by weight) in the end point steel of the electric furnace * Weight of molten steel in the electric furnace (kg) * 0.011
[Formula 6]
(Kg) = amount of steel slag discharged into electric furnace (kg) * content of iron oxide (FeO) in electric furnace end point slag (% by weight) * 0.0025
[Equation 7]
Al (A1) (kg) + (Al) input amount (kg) + (deacidizer input amount (kg) * 0.5)) - (Oxygen deoxidized aluminum (Al) the amount (kg)) - (the end point of the molten steel into an electric oxygen deoxidized aluminum (Al), the amount (kg)) - (tapping the molten steel into an electric weight (kg) * ([% Al ] LF _arrival / 100))
(In the above formula 7, the [% Al] _{LF arrival} is the aluminum content (wt%) in the molten steel arriving at the ladle.

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