KR102135757B1 - Method for coating of converter and equipment for processing hot metal - Google Patents

Abstract

In the converter coating method according to the embodiment of the present invention, when the precipitation of molten steel produced in the operation process of the previous charge is completed, the number of uses of the converter in which the molten steel is discharged and the end point oxygen concentration of the previous charge molten steel It includes the process of deriving the tilt angle of the converter, tilting the converter at the derived tilt angle, disposing a part of the slag in the converter, and introducing a coating material into the converter, injecting nitrogen, and coating the inner wall of the converter. .
Accordingly, according to the embodiment of the present invention, the coating efficiency and coating quality of the converter inner wall are improved compared to the prior art. That is, the coating defect in which the converter inner wall is not coated, locally coated, or coated slag flows back is conventional. Can be suppressed or prevented.

Description

Method for coating of converter and equipment for processing hot metal}

The present invention relates to a converter coating method and a molten iron treatment facility, and more particularly, to a converter coating method and a molten iron treatment facility capable of extending the life of the converter.

In general, the converter is a facility to remove impurities from the molten iron made in the blast furnace, or to refine the molten iron for adjustment to the content of ingredients required by the product.

In the refining method using the converter (hereinafter, the converter refining method), the process of completing the ascent of molten steel produced in the operation process of the previous charge, the exclusion process of excluding slag in the converter, and the operation of the next charge To this end, it includes the process of charging molten iron and scrap metal into the converter, the blowing process of blowing oxygen into the molten iron to remove impurities or adjusting components in the molten iron, and the process of discharging molten steel from the converter after the blow is finished.

Here, the blowing process is an operation of removing impurities in the molten iron or refining the molten iron for adjustment to a component content required by the product, as described above. In other words, if a blow is performed to blow oxygen into the molten iron in the converter, impurities contained in the molten iron, such as Si (silicon), P (phosphorus), carbon (C), etc., oxidize and react with the blown oxygen, and the reaction product is molten iron bath Is moved into the slag floating on, or removed as gas.

On the other hand, in one converter, the process of'slag exclusion, molten iron and scrap metal loading, blowing, and exiting' as described above is carried out in one cycle, and this cycle is repeated multiple times in one converter. And when the execution of one cycle is completed, the converter is considered to be used once.

The inner wall of the converter is made of refractory material to withstand high temperature heat, and the refractory material is eroded as the number of times the converter is used increases. That is, mechanical spalling due to physical impact due to charging of molten iron and scrap metal, abrasion due to stirring of the molten iron, elution of MgO component by reaction of slag and refractory, rapid temperature difference due to deterioration and cooling Due to thermal spalling, structural spalling between deteriorated refractories due to slag reaction, and impact due to deodorization through plugs provided at the bottom of the converter, the inner walls of the converter made of refractories are eroded.

In order to reduce the erosion of the converter, the inner wall of the converter is generally coated before charging the molten iron and scrap metal. That is, after the completion of the molten steel produced in the pre-charge operation process, a part of the slag generated in the pre-charge operation process is excluded (primary exclusion). Then, a coating material is introduced into the converter and nitrogen (N ₂ ) gas is blown to coat the converter inner wall, and such a coating is commonly referred to as a splash coating. Next, a secondary coating may be additionally performed by tilting the converter to coat the inner wall of the converter.

As described above, the converter is coated with the coating material and the slag, and the coating quality depends on the viscosity of the slag or the viscosity of the slag in which the coating material is mixed. That is, when the viscosity of the slag is too high, the coating is not properly performed because the splash by nitrogen blowing or the movement of the slag due to the converter tilting is not properly performed. Conversely, when the viscosity of the slag is too low, a problem occurs in which the slag is not attached or fixed to the converter inner wall and flows down.

The viscosity of the slag, which influences the quality of the converter coating, depends on the amount of slag remaining after the primary exclusion and the amount of the coating material added. In addition, as the volume of the inner wall of the converter changes as erosion progresses, it is necessary to vary the amount of slag and coating material required for coating accordingly. In addition, the viscosity of the slag before the coating material is added depends on the content, temperature, etc. of molten steel of the previous charge.

However, in the related art, a certain amount of slag remains and a certain amount of coating material is added regardless of the number of times the converter is used, the content of the molten steel in the previous charge, and the temperature.

Accordingly, the viscosity control of the slag is not appropriate, the coating is made only on a part of the inner wall of the converter, or the coating is not properly made as a whole, so that the erosion of the converter cannot be reduced or the erosion degree rises. In the end, as the converter cannot be used up to the target service life, the converter needs to be repaired early, and there is a problem that the cost of using refractory material for repairing the converter is more expensive.

The present invention provides a converter coating method and a molten iron treatment facility capable of extending the life of the converter.

The present invention provides a converter coating method and a molten iron treatment facility that can suppress or prevent erosion of the converter.

In the converter coating method according to the embodiment of the present invention, when the precipitation of molten steel produced in the operation process of the previous charge is completed, the number of uses of the converter in which the molten steel is discharged and the end point oxygen concentration of the previous charge molten steel Deriving a tilt angle of the converter according to; Tilting the converter at the derived tilt angle to exclude a portion of the slag in the converter; And a process of coating the inner wall of the converter by introducing a coating material into the converter and blowing nitrogen.

Before introducing a coating material into the converter, the process of deriving a coating material input amount according to the number of times the converter is used; And before injecting nitrogen into the converter, deriving a nitrogen intake amount according to the number of times the converter is used; Including,

In introducing the coating material into the converter, the derived coating material is injected, and in blowing nitrogen into the converter, the extracted nitrogen is injected.

The process of deriving the nitrogen injection amount may include: calculating a nitrogen injection amount by adding a basic nitrogen injection amount and a plurality of nitrogen correction amounts according to the number of times the converter is used; Comparing the calculated nitrogen intake with the reference nitrogen intake range; And according to the comparison result, the calculated nitrogen injection amount is derived as the nitrogen injection amount to be injected into the converter, or the lowest nitrogen injection amount or the highest nitrogen injection amount in the range of the reference nitrogen injection amount is nitrogen to be injected into the converter It includes; the process of deriving the nitrogen intake amount to derive from the intake amount.

When the calculated nitrogen injection amount is within the reference nitrogen injection amount range, the calculated nitrogen injection amount is derived as the nitrogen injection amount to be blown into the converter, and the calculated nitrogen injection amount is the lowest nitrogen injection amount in the reference nitrogen injection amount range. If it is less than the amount, the lowest nitrogen injection amount is derived as the nitrogen injection amount to be blown into the converter, and when the calculated nitrogen injection amount exceeds the highest nitrogen injection amount in the reference nitrogen injection amount range, the highest nitrogen injection amount The amount is derived as the amount of nitrogen blown into the converter.

The plurality of nitrogen correction amounts are nitrogen correction amounts according to the end oxygen concentration of the previous charged molten steel, nitrogen correction amounts according to the end point temperature of the previous charged molten steel, nitrogen correction amounts according to the current charge operation process, and the previous charge. It includes the amount of nitrogen correction according to the operation process of.

The amount of nitrogen correction according to the current charge operation process is determined by whether or not to carry out a vacancy to blow oxygen in order to remove the now in the converter before or after the process of excluding part of the slag in the converter. The amount of nitrogen correction according to the above, and the amount of nitrogen correction according to the operation process of the previous charge is the amount of nitrogen correction according to whether re-straining is performed during the operation process of the previous charge, and the operation amount of the previous charge is the above. After the process of coating the inner wall of the converter, the amount of nitrogen correction according to whether or not the slag in the converter is completely exhausted, and when charging the molten iron into the converter after coating the inner wall of the converter during the operation process of the previous charge, the It includes the amount of nitrogen correction according to whether or not the molten steel generated during the previous charge operation process is returned.

The basic nitrogen injection amount increases as the number of times the converter is used increases, and the amount of nitrogen correction according to the end oxygen concentration of the previous charged molten steel increases with the increase in the end oxygen concentration, and the operation of the previous charge is increased. The amount of nitrogen correction according to whether or not re-straining is performed during the process has a value of 0 (zero) or a constant amount (+) depending on whether it is carried out, and the amount of nitrogen correction according to the end temperature of the previous charged molten steel increases with the end temperature Increases, and the amount of nitrogen correction according to whether or not to perform the deodorization and the deodorization time has a value of 0 (zero) or a positive value, and increases to a positive value as the deodorization time increases, and completely excluded. The amount of nitrogen correction according to the implementation has a value of 0 (zero) or a constant negative (-) depending on whether it is carried out, and the amount of nitrogen correction according to whether the molten steel is conveyed is a 0 (zero) value or a constant amount ( +).

The process of deriving the coating material input amount includes: adding a basic coating material input amount and a plurality of coating material correction amounts according to the frequency of use of the converter to calculate a coating material input amount; Comparing the calculated coating material input amount and the reference coating material input range; And a coating material that derives the calculated coating material input amount as the coating material input amount to be input to the converter, or derives the lowest coating material input amount or the best coating material input amount of the reference coating material input range as the coating material input amount to the converter. It includes; input derivation process.

When the calculated coating material input amount is within the reference coating material input amount range, the calculated coating material input amount is derived as the coating material input amount to be input to the converter, and the calculated coating material input amount is less than the lowest coating material input amount of the reference coating material input amount range, the lowest A coating material input amount is derived as a coating material input amount to be input into the converter, and when the calculated coating material input amount exceeds the highest coating material input amount of the reference coating material input range, the best coating material input amount is derived as a coating material input amount to be input to the converter. do.

The plurality of coating material correction amounts, the amount of coating material correction according to the end oxygen concentration of the former charged molten steel, the amount of coating material correction according to the end temperature of the previous charged molten steel, the current charge operation The coating material correction amount according to the process and the coating material correction amount according to the operation process of the previous charge are included.

The amount of the coating material correction according to the current charge operation process, the amount of coating material correction according to the take-off time for blowing oxygen to remove the now in the converter before or after the process of excluding part of the slag in the converter The amount of correction of the coating material according to the operation process of the previous charge includes, the amount of correction of the coating material according to whether or not re-straining is performed during the operation process of the previous charge, and coating the inner wall of the converter during the operation process of the previous charge Correction amount of coating material according to whether or not to perform complete exclusion of all slag in the converter after the process, when the molten iron is charged into the converter after coating the inner wall of the converter during the operation process of the previous charge, before It includes the amount of coating material correction according to whether or not the former molten steel that is introduced during charging operation is returned.

The basic coating material input amount increases as the number of times the converter is used increases, and the correction amount of the coating material according to the end oxygen concentration of the previous charged molten steel increases with the increase in the end oxygen concentration, and the operation process of the previous charge The amount of coating material correction according to whether or not re-straining is performed has a value of 0 (zero) or a certain amount (+) depending on whether it is carried out, and the amount of coating material correction according to the end temperature of the previous charged molten steel is increased with the increase of the end temperature. Increases, and the amount of coating material correction according to whether or not the odor is carried out and has a value of 0 (zero) or positive (+), increases to a positive value as the odor time increases, and performs the complete exclusion. The correction amount of the coating material depending on whether or not has a value of 0 (zero) or constant negative (-) depending on whether it is carried out, and the amount of nitrogen correction depending on whether or not the molten steel is conveyed is 0 (zero) value or constant amount (+ ).

Equation 1 is used to derive the tilt angle.

[Equation 1]

A molten iron treatment facility according to an embodiment of the present invention includes a lance capable of introducing nitrogen into a converter; A coating material input device located outside the converter and for introducing a coating material into the converter; A tilt angle derivation unit for deriving a tilt angle of the converter for slag exclusion in the converter, which is carried out before coating the inner wall of the converter, according to the number of times of use of the converter and the end oxygen concentration of the former charged molten steel; And a tilting device for tilting the converter at a tilting angle derived from the tilting angle deriving unit.

A coating material input amount deriving unit for deriving a coating material input amount into the converter for coating the converter according to the number of times the converter is used; It includes; and a nitrogen injection amount deriving unit for deriving the nitrogen injection amount blown into the converter for the converter coating according to the number of times the converter is used;

The coating material input device injects the coating material with the coating material input amount derived from the coating material input amount deriving unit, and the lance blows nitrogen with the nitrogen injection amount derived from the nitrogen injection amount deriving unit.

The nitrogen injection amount deriving unit calculates a nitrogen injection amount by adding a basic nitrogen injection amount and a plurality of nitrogen correction amounts according to the number of times the converter is used, and comparing the calculated nitrogen injection amount and a reference nitrogen injection amount range, and calculating Nitrogen injection to derive the nitrogen injection amount to be injected into the converter, or to derive the lowest nitrogen injection amount or the highest nitrogen injection amount of the reference nitrogen injection amount range into the nitrogen injection amount to be injected into the converter The amount of the coating material is derived, and the coating material input amount deriving unit calculates the coating material input amount by summing the basic coating material input amount and the plurality of coating material correction amounts according to the number of times the converter is used, and comparing the calculated coating material input amount with the reference coating material input range, and calculating The coating material input amount is derived as a coating material input amount to be input to the converter, or the lowest coating material input amount or the best coating material input amount of the reference coating material input range is derived as a coating material input amount to be input to the converter.

Each of the plurality of nitrogen correction amounts and the plurality of coating material correction amounts is corrected according to the end oxygen concentration of the previous charged molten steel, the corrected amount according to the end temperature of the previous charged molten steel, and before the process of excluding part of the slag in the converter Whether or not to carry out the odor to blow oxygen in order to remove the current in the converter at (pre) or after (및), and the amount of correction according to the time taken, the amount of correction according to whether the re-straining is performed during the operation process of the previous charge, Pre-compensation amount according to whether or not full exclusion of slag in the converter is performed after the process of coating the inner wall of the converter during the charge operation process, and after coating the inner wall of the converter during the operation process of the previous charge, into the converter When charging the molten iron, it includes a correction amount depending on whether or not the molten steel generated during the previous charge operation process is returned.

The tilt angle derivation unit derives a tilt angle using Equation (1).

[Equation 1]

According to the embodiment of the present invention, an appropriate amount of slag can be left before coating according to the number of times of use of the converter and the end oxygen concentration. In addition, the nitrogen intake amount and the coating material input amount when the converter is coated are derived according to the frequency of use of the converter, the end point oxygen concentration, the end point temperature, and the operation process, and this is reflected when the converter is coated.

Due to this, the coating efficiency and coating quality of the converter inner wall are improved compared to the prior art, i.e., it is possible to suppress or prevent coating defects in which the converter inner wall is not coated, locally coated, or the coated slag flows down again. have.

Therefore, according to the converter coating method according to the embodiment of the present invention, the life of the converter is extended, and accordingly, the repair time of the converter can be delayed. In addition, this can reduce the cost of using refractory material for repairing the converter.

1 is a flow chart showing a molten iron treatment method including a converter coating method according to an embodiment of the present invention
2 is a conceptual diagram showing a molten iron treatment facility according to an embodiment of the present invention
3 is a view showing a state in which the converter of the molten iron treatment facility according to an embodiment of the present invention is tilted for slag exclusion.

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and the scope of the invention to those skilled in the art. It is provided to inform you completely.

The present invention relates to a converter coating method and a molten iron treatment facility capable of reducing erosion of the converter. More specifically, to provide an effective coating, and to improve the coating quality, it is possible to secure an appropriate amount of residual slag, and to provide a converter coating method and a molten iron treatment facility to control the slag to an appropriate viscosity.

1 is a flow chart showing a molten iron treatment method including a converter coating method according to an embodiment of the present invention. 2 is a conceptual view showing a molten iron treatment facility according to an embodiment of the present invention. 3 is a view showing a state in which the converter of the molten iron treatment facility according to an embodiment of the present invention is tilted for slag exclusion.

Referring to FIG. 1, the method of treating molten iron according to an embodiment of the present invention is a process of completing the steel steel produced in the operation process of the previous charge (S100), a process of coating the inner wall of the converter 100 (S200) ), the process of excluding the slag inside the converter 100 (S300), the process of charging molten iron and scrap metal into the converter 100 (S400), the tempering process of blowing oxygen into the molten iron to remove impurities or adjust components (S500) ) And the step of pulling steel from the converter 100 after the blow is finished (S600 ).

In addition, the method for treating molten iron according to an embodiment of the present invention terminates the vacancy process and the blowing (S500) of blowing oxygen into the converter 100 before the slag exclusion (S300) to remove the now attached to the inner wall of the converter 100 When the measured end point temperature of the molten steel is lower than the target temperature, or when the measured end point oxygen concentration of the molten steel is lower than the target oxygen concentration, a re-straining process of re-executing the blowing may be included.

Here, each of the vacancy process and the re-strain process may or may not be selectively performed.

The converter coating process (S200) is a process of deriving the converter tilt angle according to the number of times the converter 100 is used and the endpoint oxygen concentration (S211), the number of times the converter 100 is used, the previous oxygen concentration of the molten steel, the endpoint temperature, The operation process of the current charge, the process of deriving the coating material input according to the operation process of the previous charge (S212), and the slag generated in the operation process of the previous charge by tilting the converter 100 at the derived converter tilt angle The process of excluding part of S) (S210), the process of coating the inner wall of the converter 100 by supplying nitrogen and a coating material into the converter 100 with the derived coating material input (hereinafter, the primary coating process (S220)), 1 After the secondary coating is completed, a process of coating the inner wall of the converter 100 by tilting the converter 100 (hereinafter, a secondary coating process (S230)) is included.

Hereinafter, the process of excluding the slag before coating the converter is referred to as primary exclusion (S210) and the process of excluding the slag after coating the converter is referred to as secondary exclusion (S300).

2 and 3, the molten iron treatment facility according to an embodiment of the present invention is a converter (100) having an internal space, a lance (L) for introducing gas, such as oxygen and nitrogen into the converter (100), the converter ( 100) tilt angle derivation unit 200 for deriving the tilt angle of the converter 100 for slag (S) exclusion according to the number of times of use and the end oxygen concentration of the former charged molten steel, tilt angle adjustment unit 200 Tilting device 300 to tilt the converter 100 at a tilt angle derived from the converter 100, the number of times the converter 100 is used, and the end oxygen concentration of the charged charge steel, the end temperature of the molten steel, upon coating the converter 100 according to the operation process It includes a nitrogen injection amount derivation unit 400 and a coating material input derivation unit 500 for deriving each of the necessary nitrogen injection amount and the coating material input amount.

In addition, the molten iron treatment facility, the chute 600 for guiding its movement so that the refining material and coating material for refining the molten iron into the converter 100 are input, an oxygen supply device for supplying oxygen to the lance L for the molten iron ( 700), nitrogen supply device 800 for supplying nitrogen to the lance (L) with the injection amount derived from the nitrogen injection amount derivation unit 400, the coating material chute 600 with the input amount derived from the coating material injection amount derivation unit 500 It includes a coating material input device 900 provided by ).

The converter 100 is a container having an inner space in which molten iron and scrap metal are accommodated, and is made of refractory material built on the outermost shell and the inner wall of the shell, and the upper side is open (noguer 111), and the molten steel is on the side. A discharge opening 112 is provided.

The lance L is formed to extend in the vertical direction and may have a shape in which a passage through which gas can pass or pass is provided.

It is necessary to adjust the height of the lance L during converter coating and blowing, where the height of the lance L may be a separation distance from the bottom surface in the converter 100 to the end of the lance L. More specifically, the separation distance from the interface between the iron shell and the refractory material constituting the converter 100 to the end of the lance L is the height of the lance.

The chute 600 is positioned so that one end, which is the end of the extending direction, faces or faces the furnace tool 111 of the converter 100, so that each of the refining agent and the coating material supplied from the converter 100 outside the furnace 100 of the converter 100 111) to guide the movement. The suit 600 may have a shape inclined downward in the direction in which the furnace section 111 is located.

The oxygen supply device 700 is a device that supplies oxygen for blowing molten iron into the lance L. The oxygen supply apparatus 700 includes an oxygen supply unit 710 in which oxygen to be temporarily supplied to the lance L is temporarily stored, an oxygen supply line 720 having one end connected to the oxygen supply unit 710 and the other end connected to the lance L, The oxygen control unit installed on the extension path of the oxygen supply line 720 to control communication between the oxygen supply unit 710 and the oxygen supply line 720, and to control the oxygen supply amount to the lance L by the oxygen supply unit 710 ( 730).

Here, the oxygen supply line 720 may be a pipe shape having an internal space, and the oxygen control unit 730 may include a valve and a flow rate control unit installed on an extension path of the oxygen supply line 720.

The nitrogen supply device 800 is a device that supplies nitrogen for converter coating to the lance L. The nitrogen supply device 800 includes a nitrogen supply unit 810 in which nitrogen to be supplied to the lance L is temporarily stored, a nitrogen supply line 820 having one end connected to the nitrogen supply unit 810 and the other end connected to the lance L, A nitrogen control unit installed on an extension path of the nitrogen supply line 820 to control communication between the nitrogen supply unit 810 and the nitrogen supply line 820, and to control the nitrogen supply amount from the nitrogen supply unit 810 to the lance L ( 830).

Here, the nitrogen supply line 820 may be a pipe shape having an internal space, and the nitrogen control unit 830 may include a valve and a flow rate control unit installed on an extension path of the nitrogen supply line.

The coating material input device 900 includes a hopper 910 in which the coating material for temporarily coating the converter 100 is stored, a coating material supply line 920 and a hopper 910 for moving the coating material discharged from the hopper 910 to the chute 600. ) And the coating material supply line 920, the coating material control unit 930 for controlling the discharge amount of the coating material.

On the other hand, the refractory material constituting the converter 100 is generally made of MgO-C-based refractory material, and it is preferable to use a material containing a component included in the refractory material as a coating material for coating the inner wall of the converter 100. .

Therefore, a raw material containing MgO is generally used as a coating material. For example, as the coating material, at least one of light dolomite containing approximately 45 wt% MgO and raw dolomite containing 15 wt% to 30 wt% MgO may be used.

When a plurality of coating materials are provided in this way, each of the hopper 910 and the coating material supply line 920 may be provided in a plurality to store and supply each of the plurality of coating materials.

The coating material supply line 920 may have a pipe shape having an internal space through which the coating material can move. In addition, the coating material control unit 930 may include a valve for controlling the communication between the hopper 910 and the coating material supply line 920 and a basis weight part for adjusting the amount of coating material that is moved or discharged from the coating material supply unit to the chute 600. .

On the other hand, as the number of times the converter 100 is used increases, the volume in the converter 100 tends to increase due to erosion. Accordingly, as the number of times the converter 100 is used increases, the area to be coated increases, so the amount of residual slag required for coating needs to be increased.

In addition, the amount of residual slag in the converter 100 depends on the tilt angle θ (see FIG. 3 ), and the greater the tilt angle θ within a certain time, the greater the amount of slag discharged from the converter 100 and remains. The amount of slag to be reduced decreases. Conversely, the smaller the tilt angle θ within a certain time, the more the amount of slag discharged from the converter 100, and the remaining amount of slag increases.

The slag remaining in the converter 100 is then cooled by nitrogen blown, thereby increasing the viscosity. Then, the slag having an increased viscosity is scattered or splashed with nitrogen blown to be coated on the inner wall of the converter. In addition, after the primary coating (splash coating) by nitrogen injection, it is common to perform a secondary coating to incline the converter.

However, when the viscosity of the slag is too high, there is a problem that the slag does not flow or the slag does not flow at the time of tilting the converter 100 due to nitrogen being blown. Due to this, the coating on the inner wall of the converter 100 is insufficient, or a coating defect that is coated only on the local area occurs.

Conversely, when the viscosity of the slag is too low, the fluidity is too high, causing a problem that the slag coated from the inner wall of the converter 100 flows down again.

Therefore, it is necessary to adjust the slag to an appropriate viscosity. Here, the appropriate viscosity of the slag may mean a viscosity that does not flow down from the inner wall of the converter 100 while smoothly flowing or splashing the slag by nitrogen injection and tilting of the converter.

The viscosity of the slag is lower the higher the content of iron (Fe) therein. And, the iron (Fe) content in the slag is higher as the end oxygen concentration of the former charged molten steel is higher. In conclusion, the higher the end oxygen concentration of the former charged molten steel, the lower the viscosity of the slag, and, conversely, the lower the end oxygen concentration, the higher the viscosity of the slag.

The oxygen concentration at the end point of the previous charged molten steel means the oxygen concentration of the molten iron that has been blown out, that is, the molten steel. More specifically, after the blow is finished, the molten steel is sampled to measure the component content of the molten steel, where the measured oxygen concentration is the end oxygen concentration.

In addition, as the amount of residual slag increases, the amount of nitrogen required to achieve an appropriate viscosity increases. In addition, as described above, since the viscosity of the slag is low as the end point oxygen concentration increases, the amount of nitrogen and time required to achieve an appropriate viscosity increases as the amount of residual slag increases.

Accordingly, in order to prevent an increase in the nitrogen injection amount and an increase in the nitrogen injection time, it is necessary to appropriately adjust the residual slag amount for coating.

Therefore, the tilt angle derivation unit 200 according to the embodiment derives the optimum tilt angle of the converter according to the number of times the converter is used and the end point oxygen concentration, and converts the converter 100 to the tilt angle θ derived at the time of primary exclusion. By tilting, an appropriate amount of slag remains in the converter 100 after the primary exclusion.

To this end, the tilt angle derivation unit 200 inputs the number of converter use times and the end point oxygen concentration data of the previous charged molten steel. In addition, the tilt angle derivation unit 200 derives the tilt angle using the input converter number of use and the end point oxygen concentration. The tilt angle can be derived using Equation 1 below.

[Equation 1]

In Equation 1, the denominator '96.1+ (0.00309 * number of converter use)-(0.0200 * end point oxygen concentration (ppm))' may be an empirical formula according to the volume criteria inside the converter. In addition, Equation 1 may be an equation applied when coating a converter in which a molten steel of 250 t/ch is charged.

Here,'t/ch' means the amount of molten iron (ton) charged per charge. In addition, in applying the converter use frequency and the end point oxygen concentration to Equation 1, it is applied without a unit, and the derived numerical value is a tilt angle (°) derived value.

Hereinafter, a method of deriving a tilt angle using Equation 1 will be described as an example. For example, when the converter is used 100 times and the end oxygen concentration of the previous charge molten steel is 300 ppm, when these are applied to Equation 1, the derived value is 90.5, and the derived tilt angle is 90.5°.

The tilt angle derivation unit 200 derives the tilt angle according to the number of times of use of the converter and the end point oxygen concentration by the above-described method, as shown in Table 1 below.

division End point oxygen concentration (ppm) Number of times the converter was used (times) 250 300 350 400 450 500 550 600 650 700 One 90 89 88 87 86 85 84 83 82 81 100 91.5 90.5 89.5 88.5 87.5 86.5 85.5 84.5 83.5 82.5 500 93 92 91 90 89 88 87 86 85 84 1000 94.5 93.5 92.5 91.5 90.5 89.5 88.5 87.5 86.5 85.5 1500 96 95 94 93 92 91 90 89 88 87 2000 97.5 96.5 95.5 94.5 93.5 92.5 91.5 90.5 89.5 88.5 2500 99 98 97 96 95 94 93 92 91 90 3000 100.5 99.5 98.5 97.5 96.5 95.5 94.5 93.5 92.5 91.5 3500 102 101 100 99 98 97 96 95 94 93 4000 103.5 102.5 101.5 100.5 99.5 98.5 97.5 96.5 95.5 94.5 4500 105 104 103 102 101 100 99 98 97 96 5000 106.5 105.5 104.5. 103.5 102.5 101.5 100.5 99.5 98.5 97.5 5500 108 107 106 105 104 103 102 101 100 99 6000 109.5 108.5 107.5 106.5 105.5 104.5 103.5 102.5 101.5 100.5

The tilt angle derived through Equation 1 in the tilt angle deriving unit 200 is transmitted to the tilt device 300. Then, when tilting the converter 100 for primary exclusion, the tilting device 300 tilts the converter 100 to incline at the derived tilt angle.

Accordingly, the slag may be excluded so that an appropriate amount of slag remains according to the number of times of use of the converter and the end point oxygen concentration.

In the above-described tilt angle derivation unit 200, it has been described that the tilt angle of the converter 100 is derived when coating the converter 100 into which the main raw materials (melting iron and scrap metal) of 250 ton/ch are charged.

However, the present invention is not limited thereto, and various amounts or volumes of converters may be applied. At this time, the amount of molten steel (ton/ch) charged into the converter is applied to the molecule of Equation 1, and constants such as 96.1, 0.00309, and 0.0200 in the denominator are applied to the molten steel quantity (ton/ch) or converter volume charged into the converter. It changes according to the experience of the worker.

Hereinafter, the derivation of nitrogen intake and the derivation of coating material will be described.

The inner wall of the converter 100 includes a side wall and a bottom surface (a bottom part), and the height of the lance L for blowing nitrogen as shown in Table 2, depending on where the inner wall of the converter 100 is coated, nitrogen injection per minute It is desirable to adjust the amount (Nm ³ /min) differently. In addition, when the start time of nitrogen injection for the converter coating is 0% and the time for ending nitrogen injection is 100%, it is necessary to adjust the height of the lance L and the nitrogen injection amount per minute according to the nitrogen injection time. desirable.

division Nitrogen injection time 0%~30% or less More than 30%~80% 80% or more ~ 100% or less Sidewall coating Lance height (cm) 450 450 450 N ₂ intake (Nm ³ /min) 850 850 850 Floor coating Lance height (cm) 450 500 600 N ₂ intake (Nm ³ /min) 850 800 800

As described above, the appropriate amount of slag to be retained varies depending on the number of times the converter 100 is used, and the nitrogen intake amount for adjusting the appropriate viscosity varies depending on the amount of slag.

In addition, the viscosity increases as the amount of the solid phase mixed into the slag increases, and conversely, the viscosity decreases as the amount of the solid phase decreases. Since the coating material is a solid phase, the viscosity of the slag varies according to the amount of the coating material.

And, as well as the number of times the slag is used, the end oxygen concentration of the former charged molten steel, the temperature of the endpoint of the former charged molten steel, the nitrogen intake amount and coating material according to the operation process of the current charge and the operation process of the previous charge It is necessary to vary the input amount.

Here, the operation process of the current charge may include whether the current charge is carried out or not, and the time of the public charge. In addition, the operation process of the previous charge includes whether or not retraining is performed in the previous charge, whether or not complete exclusion is performed in the previous charge, and whether slag is returned in the previous charge.

Accordingly, in deriving the nitrogen injection amount to be supplied to the lance L in the embodiment of the present invention, the nitrogen injection amount according to the number of times the converter is used is the basic nitrogen injection amount, and the basic nitrogen injection amount is corrected with a plurality of nitrogen correction amounts. Then, the amount of nitrogen blown to be supplied to the lance L is derived. Here, the plurality of nitrogen correction amounts are the end oxygen concentration of the previous charge molten steel, the temperature of the end point of the previous charged molten steel, whether or not vacancy is performed at the current charge, and whether or not the vacancy is performed at the current charge, whether or not re-straining is performed at the previous charge. It includes the amount of nitrogen correction according to whether or not full exclusion is carried out in the previous charge and slag is returned in the previous charge.

In addition, in deriving the coating material input amount to be supplied to the converter 100, the coating material input amount according to the number of times the converter is used is the basic coating material input amount, and the basic coating material input amount is corrected with a plurality of coating material correction amounts to input the coating material input to the converter 100 To derive. Here, the correction amount of the plurality of coating materials is the end oxygen concentration of the former charged molten steel, the temperature of the endpoint of the former charged molten steel, whether or not the deodorization is performed at the current charge, and whether the deodorization is performed at the previous charge, whether or not re-straining is performed at the previous charge, before It includes the amount of coating material correction according to whether or not full exclusion is carried out in the previous charge and slag is returned in the previous charge.

At this time, the coating material may use at least one of raw dolomite and light dolomite, and the basic coating material input amount and the coating material correction amount may be different depending on the type of the coating material.

Hereinafter, the basic input amount of raw dolomite among the basic coating material inputs is referred to as a basic raw dolomite input amount, and the basic input amount of light small dolomite is referred to as a basic light dolomite input amount.

In addition, of the amount of correction for the coating material, the amount of correction for raw dolomite is referred to as the amount of correction for dolomite, and the amount of correction for light dolomite is referred to as the amount of correction for small dolomite.

Hereinafter, the basic nitrogen injection amount and the basic coating material input amount according to the number of times the converter is used will be described.

division Number of converter use Less than 50 times 50 or more times
3000 times or less Over 3000~4000 Over 4000 to under 5000 Over 5000 Basic nitrogen intake (Nm ³ ) 0 1000 1200 1500 1500 Sidewall
coating Basic raw dolomite input (kg) 0 600 800 900 1000 Basic light dolomite input (kg) 0 1100 1200 1300 1400 floor
coating Basic raw dolomite input (kg) 0 700 800 1000 1000 Basic light dolomite input (kg) 0 500 800 1000 1000

Referring to Table 3, the basic nitrogen injection amount and the basic coating material input amount vary depending on the number of times of using the converter, more specifically, 1 time to less than 50 times, more than 50 times to less than 3000 times, more than 3000 times to less than 4000 times , More than 4000 times to 5000 times or less and more than 5000 times.

The basic nitrogen injection amount and the basic coating material input amount tend to increase as the number of converter uses increases. More specifically, the basic nitrogen blowing amount of the converter using the number of times when less than one or more times to 50 times 0Nm ^3, when more than 50 times to 3000 times or less than 1000Nm ^3, 3000 times to 4000 times or less when 1200Nm ^3, 4000 times more than when to 5000 times less than to a 1500Nm ³ when it exceeds a 1500Nm ^3, 5000.

In addition, the input amount of the basic coating material also varies depending on the number of times the converter is used and which of the side walls and the floor.

For example, taking the sidewall coating as an example, the basic dosage of Saint-Dolomite varies depending on the number of times the converter is used. More specifically, it is 0 kg when it is 1 or more and less than 50 times, 600 kg when it is 50 or more and 3000 times or less, more than 3000 and 4000 or more 800kg for less than 4,000 times, 900kg for more than 4,000 times or less, and 1000kg for more than 5000 times.

In addition, when coating the side walls, the basic input amount of light dolomite varies depending on the number of times the converter is used. More specifically, it is 0 kg when it is 1 or more to less than 50 times, 1100 kg when it is 50 or more to 3000 times or less, and more than 3000 or more than 3000 times or less When it is 1200kg, it is 1300kg when it is over 4000~5000 times, and 1400kg when it is over 5000 times.

The case of coating the bottom of the converter is not described further, but it is as described in Table 3.

The basic nitrogen injection amount and the basic coating material input amount according to the number of converter usages shown in Table 3 may not be the final injection and input amount for the converter coating, and the end point oxygen concentration described later from the basic nitrogen injection amount and the basic coating material input, End point temperature, the amount of nitrogen correction according to the current charging operation process (whether or not to take off air and the time to take air), the operation process of the previous charge (whether re-refining is performed from the previous charge, whether to perform full exclusion from the previous charge, or before) Nitrogen correction amount and coating material correction amount according to (pre-charge, whether or not carrying-out operation is performed) are summed to derive nitrogen injection amount and coating material input amount to be injected into and input to the converter 100.

However, as described above, when the number of times the converter is used is less than 50 times, each of the basic nitrogen injection amount and the amount of the basic coating material is 0, which means that the converter is not repaired when the number of times of use is less than 50 times.

In other words, if the converter is used less than 50 times, the end oxygen concentration of the previous charge, whether or not re-straining has been performed, the end temperature of the previous charge, whether or not it has been emptied, and whether it has been emptied, whether or not the previous charge is completely excluded, and whether molten steel is returned to the previous charge Regardless of whether or not nitrogen is blown into the converter or a coating material is added, coating is not performed.

The viscosity of the slag depends on the endpoint oxygen concentration of the previous charged molten steel as described above. Accordingly, in order to have an appropriate viscosity, it is necessary to adjust the nitrogen injection amount and the coating material input amount to be blown into the slag according to the end point oxygen concentration.

In other words, each of the basic nitrogen intake amount and the basic coating material input amount needs to be corrected according to the end point oxygen concentration. Accordingly, the nitrogen correction amount (hereinafter referred to as the first nitrogen correction amount) and the coating material correction amount (hereinafter referred to as the first coating material correction amount) according to the end point oxygen concentration are presented, and the nitrogen injection amount and the coating material input amount to be blown and injected into the converter are calculated using the same. .

division End point oxygen concentration (ppm)
300 or more to 450 or less Over 450~600 Over 600~700 Over 700~900 Over 900 First nitrogen correction amount (Nm ³ ) 0 300 400 500 500 First raw dolomite correction amount (kg) 0 0 200 200 300 1st light dolomite correction amount (kg) 0 0 400 500 500

The first nitrogen correction amount and the first coating material correction amount depend on the end point oxygen concentration. More specifically, as shown in Table 4, the end point oxygen concentration is 300 or more to 450 or less, 450 or more to 600 or less, 600 or more to 700 or less. , More than 700 ~ 900, based on more than 900.

Each of the first nitrogen correction amount and the first coating material correction amount according to the end point oxygen concentration of the previous charge molten steel may have a tendency to increase as the end point oxygen concentration increases. More specifically, each of the first nitrogen correction amount and the first coating material correction amount (ie, the first raw dolomite correction amount and the first light dolomite correction amount) according to the end point oxygen concentration may have a positive value and a zero value. These are corrected by adding them to each of the basic nitrogen intake amount and the basic coating material input amount.

On the other hand, the temperature and the oxygen concentration of the molten steel are measured after the blow is finished. At this time, if the measured molten steel temperature is lower than the target molten steel temperature or the measured oxygen concentration is lower than the target oxygen concentration, it is retaken before going out. Practice.

Accordingly, a nitrogen correction amount (hereinafter referred to as a second nitrogen correction amount) and a coating material correction amount (hereinafter referred to as a second coating material correction amount) are presented according to whether or not re-straining is performed, and the nitrogen injection amount and the coating material input amount to be blown and injected into the converter are derived by using this. .

division Retraining No retraining Second nitrogen correction amount (Nm ³ ) 100 0 2nd raw dolomite correction amount (kg) 100 0 2nd light dolomite correction amount (kg) 100 0

Referring to Table 5, the second nitrogen correction amount and the second coating material correction amount (that is, the second raw dolomite correction amount and the second light dolomite correction amount) are determined according to whether re-straining is performed, and nitrogen injection to be injected and injected into the converter It is used to derive the amount and coating material input.

Each of the correction amount of the second nitrogen and the correction amount of the second coating material depending on whether or not re-scalding is performed during the operation process of the previous charge has a value of 0 (zero) or a constant amount (+) depending on whether or not it is performed. More specifically, when the re-straining is not performed, each of the second nitrogen correction amount and the second coating material correction amount is 0 (zero), and the second nitrogen correction amount is 100 Nm ³ , the second raw dolomite correction amount, and the second minor dolomite correction amount. Is 100 kg.

The viscosity of the slag decreases as the temperature increases, and conversely increases as the temperature decreases. In addition, the temperature of the residual slag for coating the converter depends on the end point oxygen temperature.

Accordingly, the nitrogen injection amount and the coating material input amount to be blown into and supplied to the converter are derived using the nitrogen correction amount (hereinafter, the third nitrogen correction amount) and the coating material correction amount (hereinafter, the third coating material correction amount) according to the end point temperature.

division End point temperature (℃) 1600 or more~1645 or less 1645 to 1660 1660 to 1670 1670 to 1685 More than 1685 3rd nitrogen correction amount (Nm ³ ) 0 500 600 800 800 3rd raw dolomite correction amount (kg) 0 0 200 500 500 3rd light dolomite correction amount (kg) 0 0 250 500 500

The third nitrogen correction amount and the third coating material correction amount (the third raw dolomite correction amount and the third light dolomite correction amount) are determined according to the end point temperature, and more specifically, as shown in Table 6, the end point temperature is 1600°C or more to 1645°C or less, 1645 It is based on the temperature exceeding 1C to 1660C, exceeding 1660C to 1670C, exceeding 1670C to 1685C, and exceeding 1685C.

The correction amount of the third nitrogen and the correction amount of the third coating material according to the end point temperature of the former charge molten steel tends to increase with the increase of the end point temperature.

That is, the third nitrogen correction amount and the third coating material correction amount according to the end point temperature (ie, the third raw dolomite correction amount and the third light dolomite correction amount) may have a value of 0 (zero) and a positive value (+), and the end temperature As the increase, the third nitrogen correction amount and the third coating material correction amount may have a tendency to increase to a positive value, and these are used to derive the nitrogen injection amount and the coating material input amount to be blown and charged into the converter.

On the other hand, if now is attached to the inner wall of the converter, it is possible to perform a vacancy to blow oxygen into the converter before or after the primary exclusion for removal now. When oxygen is blown in, oxygen and Fe in the cage are oxidized, and accordingly the liquid is liquefied and dissolved into slag. Accordingly, as the odor time increases, the amount of Fe in the slag increases, and as described above, the amount of Fe in the slag decreases, so the viscosity of the slag decreases. In other words, this means that the viscosity of the slag decreases as the odor time increases.

Accordingly, it is necessary to correct each of the basic nitrogen intake amount and the coating material nitrogen input amount according to whether or not the deodorization is performed and the detonation time. Accordingly, the nitrogen intake amount and the coating material input amount to be blown into and input to the converter are derived by using the nitrogen correction amount (hereinafter, the fourth nitrogen correction amount) and the coating material correction amount (hereinafter, the fourth coating material correction amount) according to whether or not the odor is carried out and the vacancy time.

division Depletion time (sec) No exploitation (0 sec) 0 seconds to 120 seconds More than 120 seconds to less than 300 seconds Over 300 4th nitrogen correction amount (Nm ³ ) 0 200 500 500 Corrected amount of 4th dolomite (kg) 0 0 200 300 4th small dolomite correction amount (kg) 0 300 200 300

The correction amount of the fourth nitrogen and the correction amount of the fourth coating material (the correction amount of the fourth raw dolomite and the correction amount of the fourth light dolomite) are determined according to the deodorization time, more specifically, 0 second (no deodorization), more than 0 second to 120 seconds or less, 120 It is based on more than 300 seconds or less and more than 300 seconds.

The amount of nitrogen correction according to whether or not deodorization is carried out and the deodorization time has a value of 0 (zero) or positive (+), and as the deodorization time increases, it increases to a positive (+) value. It is used to derive each of nitrogen injection amount and coating material input amount.

More specifically, the fourth correction amount of nitrogen was 500Nm ³ when gongchwi time exceeds a fourth correction amount for a nitrogen 200Nm ^3, 120 seconds when less than 0 seconds to 120 seconds.

In addition, when the take-off time is greater than 0 seconds and less than 120 seconds, the fourth raw dolomite correction amount (kg) is 0 kg, the fourth hard dolomite correction amount (kg) is 300 kg, and when it exceeds 120 seconds and is 300 seconds or less, the fourth minor dolomite correction amount (kg) and the fourth light dolomite correction amount (kg) are 200 kg, respectively, and the fourth light dodolite correction amount (kg) exceeding 300 seconds and the fourth light dodolite correction amount (kg) are 300 kg, respectively.

On the other hand, the slag contains impurities from the molten iron blow, but the high basicity of the slag after the blow has been completed serves to improve the blowing efficiency in blowing the next molten iron.

Accordingly, after the converter coating is completed, in the slag in the converter by secondary exclusion, the slag is partially left in the converter except in special cases such as changing operating conditions and changing steel grades.

In addition, in the second exclusion of the previous charge, compared with the case where all the slag is excluded (hereinafter, completely excluded), the amount of the slag of the current charge is greater when the complete exclusion is not performed. In addition, as the amount of slag increases, it is necessary to increase the amount of nitrogen injected and the amount of coating material to be blown to cool the slag or to adjust the viscosity.

Accordingly, the nitrogen injection amount and the coating material input amount to be blown into and supplied to the converter are derived by using the nitrogen correction amount (hereinafter, the fifth nitrogen correction amount and the coating material correction amount (hereinafter, the fifth coating material correction amount)) depending on whether or not complete exclusion is performed.

division Exclusion of previous charges The previous charge has not been completely excluded. 5th nitrogen correction amount (Nm ³ ) -300 0 The amount of correction for the fifth raw dolomite (kg) -200 0 5th minor dolomite correction amount (kg) -200 0

The fifth nitrogen correction amount, the fifth raw dolomite correction amount, and the fifth minor dolomite correction amount vary depending on whether or not full charge is applied to the previous charge. At this time, the amount of nitrogen correction according to whether or not complete exclusion is performed has a value of 0 (zero) or a constant negative value (-) depending on whether or not it is performed. More specifically, when complete exclusion is performed in the previous autonomy, the fifth nitrogen correction amount is -300 Nm ³ , the fifth raw dolomite correction amount is -200 kg, and the fifth minor dolomite correction amount is -200 kg.

On the other hand, after the blow is finished, the molten steel is sampled to measure the component content. If the measured component content of the molten steel does not satisfy the target component content, it cannot be used for casting operation. Accordingly, when the component content of the molten steel of the current charge does not satisfy the target component content, when the molten iron is charged from the next charge to the converter, the previous molten steel is charged together and this is called a molten steel conveying operation.

Accordingly, in the embodiment, the amount of nitrogen correction (hereinafter referred to as the sixth nitrogen correction amount and the coating material correction amount (hereinafter referred to as the sixth coating material correction amount) according to whether or not a molten steel conveyance operation in which the molten steel of the previous charge is charged is performed during the molten iron treatment process of the previous charge) It is used to derive the amount of nitrogen blown and the amount of coating material to be blown and fed into the converter.

division Transfer of molten steel to the former charge The transfer of molten steel from the previous charge has not been carried out. 6th nitrogen correction amount (Nm ³ ) 500 0 Corrected amount of 6th raw dolomite (kg) 200 0 6th small dolomite correction amount (kg) 500 0

Referring to Table 9, the sixth nitrogen correction amount, the sixth raw dolomite correction amount, and the sixth small dolomite correction amount differ depending on whether or not the molten steel conveyance operation was performed for the previous charge. At this time, the amount of nitrogen correction according to whether or not the molten steel is conveyed has a value of 0 (zero) or a constant amount (+) depending on whether or not it is carried out. That is, when the molten steel conveying operation is performed at the electronic value, the sixth nitrogen correction amount is 500 Nm ³ , the sixth dolomite correction amount is 200 kg, and the sixth light dolomite correction amount is 500 kg.

Hereinafter, the amount of nitrogen to be blown into the converter for the converter coating using the basic nitrogen injection amount and the first to sixth nitrogen correction amount, and the converter for the converter coating using the basic coating material input amount and the first to sixth coating material correction amount How to derive the amount of coating material to be introduced will be described.

First, after the exit of the previous charge molten steel is completed, the operator checks the inside of the converter 100, whether the coating of the converter 100 is necessary, and if necessary, where to coat the side walls and the bottom of the converter 100 Decide.

Hereinafter, an example will be described as coating the sidewalls of the converter 100.

When it is determined to coat the side walls of the converter 100, the nitrogen injection amount derivation unit 400 derives the nitrogen injection amount to be injected when converting the converter, and the coating material input derivation unit 500 determines the coating material input amount to be input when the converter is coated. To derive.

First, a method for deriving the nitrogen intake amount will be described. In the nitrogen injection amount derivation unit 400, the number of times the converter was used, the end oxygen concentration of the former charged molten steel, whether or not re-straining was performed in the previous charged, the endpoint temperature of the previous charged molten steel, the current charge operation Whether or not to perform vacancy and the vacancy time, whether to perform full exclusion from the previous charge, and whether to carry out the molten steel transfer operation from the previous charge are entered.

The nitrogen injection amount deriving unit 400 automatically derives the nitrogen injection amount from the input data.

That is, the basic nitrogen intake amount is determined according to the number of times the converter is used. For example, when the number of times the converter is used is 50 or more and 3000 or less, the basic nitrogen intake is 1000 Nm ³ . Thereafter, the basic nitrogen intake amount (1000 Nm ³ ) is corrected by adding the first to sixth nitrogen correction amounts.

For example, the end point oxygen concentration is more than 600ppm, 700ppm or less, the end point temperature is more than 1645°C, 1660°C or less, the odor time is more than 0 seconds, and 120 seconds or less, no re-straining was performed in the previous charge, and complete exclusion was performed. , if it is not subjected to the molten steel transfer operation in the previous charge, the first nitrogen correction amount 400Nm ^3, the second nitrogen correction amount 0Nm ^3, a third nitrogen correction amount 500Nm ^3, the fourth nitrogen correction amount 200Nm ^3, claim 5, nitrogen correction amount The correction amount of -300 Nm ³ and the sixth nitrogen is 0 Nm ³ .

The nitrogen injection amount derivation unit 400 adds the first to sixth nitrogen correction amounts to the basic nitrogen injection amount (refer to Equation 1 below).

[Calculation formula 1]

Nitrogen injection amount calculated = 1000 Nm ³ (basic nitrogen injection amount) + 400 Nm ³ (first nitrogen correction amount) + 0Nm ³ (2nd nitrogen correction amount) + 500Nm ³ (third correction amount of nitrogen) + 200Nm ³ (fourth correction amount nitrogen) - 300Nm ³ (the fifth correction amount of nitrogen) + 0Nm ³ (sixth nitrogen blowing amount) = 1800Nm ³

Referring to the results of the above calculation formula, the nitrogen intake calculated value is 1800 Nm ³ .

Thereafter, the nitrogen injection amount deriving unit 400 compares whether the calculated nitrogen injection amount falls within a reference nitrogen injection amount range. Here, the reference nitrogen blowing amount range may be more than 350Nm ³ ~ 2500Nm ³ (see Table 10).

When the calculated nitrogen injection amount is within the reference nitrogen injection amount range, the calculated nitrogen injection amount is finally derived as the nitrogen injection amount to be injected through the lance.

However, when the calculated nitrogen injection amount is less than the lowest nitrogen injection amount in the reference nitrogen injection amount range, the lowest nitrogen injection amount is finally derived as the nitrogen injection amount to be injected through the lance L. Conversely, when the calculated nitrogen injection amount exceeds the highest nitrogen injection amount in the reference nitrogen injection amount range, the best nitrogen injection amount is finally derived as the nitrogen injection amount to be injected through the lance L.

Since the nitrogen injection amount 1800 Nm ³ calculated in the above-described example is within the reference nitrogen injection amount range, the calculated value of 1800 Nm ³ is finally derived as the nitrogen injection amount to be injected into the lance.

division The lowest limit The highest limit Nitrogen intake (Nm ³ ) 500Nm ³ 2000Nm ³ Saint Dolomite input (kg) 500kg 2000kg Light Dolomite Input (kg) 500kg 3000kg

In addition, in the input amount of the coating material input unit 500, the number of times the converter was used, the end oxygen concentration of the former charged molten steel, whether or not re-straining was performed in the previous charged, the endpoint temperature of the previous charged molten steel, the current The charge operation includes whether or not to perform vacancy and the vacancy time, whether to perform full exclusion from the previous charge, and whether to carry out the molten steel return operation from the previous charge.

Then, the coating material input amount deriving unit 500 automatically calculates the coating material input amount from the input data.

Since the converter has been used more than 50 times and less than 3000 times, the basic dolomite input amount is 600 kg, and the basic light dolomite input amount is 1100 kg.

Thereafter, the first to sixth raw dolomite correction amounts are added to and corrected by adding the first to sixth dodolite correction amounts to the basic dolomite input amount (600 kg), and the first to sixth minor dolomite correction amounts are added to the basic dolomite correction amount to be corrected.

The end point oxygen concentration is more than 600ppm, 700ppm or less, the end point temperature is more than 1645°C, 1660°C or less, the odor time is 120 seconds or less, no re-straining was performed on the previous charge, complete exclusion was performed, and molten steel was returned to the previous charge. Since the operation was not performed, the first amount of dolomite correction was 200 kg, the amount of correction for the second dodolite was 0 kg, the amount of correction for the third dodolite was 0 kg, the amount of correction for the fourth dodolite was 0 kg, the amount of correction for the fifth Saint dolomite was-200 kg, the sixth The amount of fresh dolomite correction is 0 kg.

In addition, the first minor dolomite correction amount is 400 kg, the second minor dodolite correction amount is 0 kg, the third minor dodolite correction amount is 0 kg, the fourth minor dodolite correction amount is 300 kg, the fifth minor dolomite correction amount is-200 kg, the sixth minor dolomite correction amount is 0 kg to be.

The coating material input amount deriving unit 500 adds the first to sixth raw dolomite correction amounts to the basic raw dolomite intake amount (refer to Equation 2 below). In addition, the coating material input amount deriving unit 500 adds the first to sixth small dolomite correction amounts to the basic small dolomite intake amount (refer to equation 3 below).

[Calculation formula 2]

Saint dolomite input calculated = 600 kg (basic dolomite input) + 200 kg (1st dolomite correction amount) + 0kg (2nd raw dolomite correction amount) + 0kg (3rd St. Dolomite correction amount) + 0kg (4th St. Dolomite correction amount)-200kg (5th St. Dolomite correction amount) + 0kg (6th St. Dolomite correction amount) = 600kg

[Calculation formula 3]

Calculation of light dolomite input = 1100kg (basic light dolomite input) + 400kg (1st light dolomite correction amount) + 0kg (2nd light dolomite correction amount) + 0kg (3rd light dolomite correction amount) + 300kg (4th small dolomite correction amount)-200kg (5th small dolomite correction amount) + 0kg (6th small dolomite correction amount) = 1600kg

Referring to the results of the above calculation formula, the calculated output value of raw dolomite is 600 kg, and the calculated output value of light dolomite is 1600 kg.

Thereafter, the coating material input amount deriving unit 500 compares whether the calculated coating material input amount falls within a coating material input reference range. Here, the input standard range for raw dolomite may be 500 kg or more to 4000 kg, and the input standard range for light and small dolomite may be 500 kg or more to 2000 kg (see Table 10).

When each of the calculated dolomite input amount and the light dolomite input amount is within the reference range of the biosolodomite input and the reference range of the light dolomite, the calculated dolomite input and the light dolomite input are finally derived as inputs to be input into the converter 100.

However, if each of the calculated dolomite input and light dolomite input is less than the lowest input, the lowest input is finally derived as the input to be input into the converter 100. Conversely, when the calculated dolomite input amount and the light dolomite input amount exceed the upper limit input amount of the reference range, the upper limit input amount is finally derived as the input amount to be input into the converter 100.

Since the amount of raw dolomite calculated in the above-described example is 600 kg, it is within the reference range of the raw dolomite input, so the calculated value of 600 kg is finally derived as the amount of raw dolomite to be fed into the converter.

In addition, since the calculated amount of light dolomite is 1600 kg is within the reference range of light dodolite, the calculated value of 1600 kg is finally derived as the amount of light dolomite to be injected into the converter.

When the nitrogen injection amount and the coating material input amount are derived in the same manner as described above, this is reflected in the converter coating. That is, nitrogen is injected into the derived nitrogen injection amount, and the coating material is injected into the derived coating material injection amount.

Hereinafter, a method for treating molten iron including a converter coating method according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3.

When the previous charging of the molten steel is completed (S100), the operator checks the inside of the converter 100 to determine whether it is necessary to remove it through vacancy, whether to coat the inner wall of the converter 100, and where to apply the coating.

If it is determined that deodorization is necessary, deodorization is performed by blowing oxygen into the converter 100 using the lance L. Now, the inside of the inner wall of the converter is melted by the blown oxygen and dissolved into slag. Then, whether or not to perform the odor in the current charge, the emptiness time is transmitted to the coating material input amount deriving unit 500.

If it is determined by the operator that coating of the inner wall of the converter 100 is necessary, and if it is determined that coating is required among the side walls and the bottom of the converter 100, the tilt angle derivation unit 200 of the converter 100 during the primary exclusion Derive the tilt angle.

That is, the tilt angle derivation unit 200 derives the tilt angle for the primary exclusion using the number of uses of the converter used in the current charge and the end oxygen concentration of the previous charge molten steel (S211). At this time, the tilt angle derivation unit may derive the tilt angle using Equation 1.

For example, if the converter is used 100 times and the end oxygen concentration of the previous charged molten steel is 300 ppm, the tilt angle derived by Equation 1 is 90.5°.

The tilt angle derived from the tilt angle derivation unit 200 is transmitted to the tilt device 300, and the tilt device 300 tilts the converter so that the angle of the converter is 90.5°. At this time, the tilting device 300 may tilt the converter 100 in stages without tilting it at 90.5° at a time. For example, after the converter 100 is tilted to 10° to 80°, the port P is positioned below the converter 100, and then the converter is tilted to 90.5°. The stepwise tilting of the converter is intended to secure the port position.

When the converter 100 is tilted, slag is discharged, that is, discharged (S210) from the furnace 111 of the converter 100 for a predetermined time, for example, 3 seconds, and the exhausted slag is a port P located under the converter 100 ) Is charged into.

As described above, as the converter 100 is tilted at a tilt angle derived according to the number of uses of the converter 100 and the end oxygen concentration, a suitable amount of slag can be left.

In the above, it has been described that the excavation for removal is carried out before the first exclusion, but it may be carried out after the first exclusion.

When the primary exhaust is finished, nitrogen is blown into the converter 100 through the lance L, and a coating material is introduced to coat the converter (S220).

Prior to the coating of the converter 100, the nitrogen injection amount derivation unit 400 and the coating material input derivation unit 500 respectively derive the nitrogen injection amount to be injected through the lance L and the coating material input amount to be input into the converter 100. (S212).

That is, the number of times the converter has been used in the nitrogen intake deriving unit 400, the oxygen concentration of the previous charged molten steel, whether or not re-straining is performed in the previous charged, the temperature of the previous charged molten steel, the current charge When it is input whether or not the vacancy is carried out and the vacancy time, whether or not complete exclusion is performed in the previous charge and whether or not the molten steel conveyance operation is performed in the previous charge, the nitrogen intake amount derivation unit 400 determines the basic nitrogen intake amount and the The 1st to 6th nitrogen correction amounts are added up.

At this time, when the calculated nitrogen injection amount is within the nitrogen injection allowable range, the nitrogen injection amount calculated by the nitrogen injection amount derivation unit 400 is derived as the nitrogen injection amount to be blown into the lance L, and the nitrogen injection device 800 Transfer to.

However, when the calculated nitrogen injection amount is less than the lowest nitrogen injection amount in the reference nitrogen injection amount range, the minimum nitrogen injection amount is finally derived as the nitrogen injection amount to be blown through the lance, and this is transmitted to the nitrogen supply device 800 do. Conversely, when the calculated nitrogen injection amount exceeds the highest nitrogen injection amount in the reference nitrogen injection amount range, the best nitrogen injection amount is finally drawn as the nitrogen injection amount to be injected through the lance L, and this is a nitrogen supply device (800).

In addition, the number of times the converter was used in the coating material input derivation unit 500, the oxygen concentration of the previous charged molten steel, whether or not re-straining was performed in the previous charged, the temperature of the previous charged molten steel, the current charge When it is input whether or not the vacancy is performed and the vacancy time, whether to perform complete exclusion from the previous charge and whether to carry out the molten steel conveyance operation from the previous charge, the coating material input derivation unit 500 is the basic raw dolomite input amount and the first The sixth to sixth dolomite correction amounts are summed to calculate the amount of raw dolomite input, and the first to sixth dolomite correction amounts are summed to calculate the amount of light dolomite input.

In this case, if the calculated amount of raw dolomite and light dolomite are each within the range of the reference raw dolomite input and the reference light dolomite input, the calculated dodolite input and light dodolite input are derived as the raw dolomite input and the light dolomite input to be converted into the converter. , This is transmitted to the coating material input device 900.

However, if the calculated amount of raw dolomite and light dolomite is less than the minimum amount of the reference raw dolomite input and the reference light dolomite input range, the final draw is finalized by the amount of the small dolomite and the small dolomite input to be fed into the converter. This is transmitted to the coating material input device 900. Conversely, when the calculated dolomite input amount and the light dodolite input amount exceeds the highest input amount of the reference raw dolomite input amount and the reference light dodolite input range, the final derivation is ultimately derived from the dolomite input amount and the light dolomite input amount to be fed into the converter. Then, it is transferred to the coating material input device 900.

Thereafter, for coating the converter 100, the nitrogen supply device 800 supplies nitrogen to the lance L, and the coating material supply device 900 inputs the coating material to the chute 600. At this time, the nitrogen supply device 800 is controlled so that the nitrogen injection amount drawn from the lance 200 is the derived nitrogen injection amount, the coating material supply device 900 is the amount of each of dolomite and light dolomite introduced into the converter 100 It is controlled to be the derived amount.

When nitrogen is blown into the converter 100 and the coating material is introduced, the slag and the coating material or a mixture thereof are scattered or splashed by nitrogen blowing to be coated (primary converter coating) on the inner wall of the converter 100 (S220).

When the primary converter coating is finished, the converter 100 is then tilted to coat the converter 100 by secondly flowing the remaining slag after the primary coating (S230).

When the secondary converter coating is finished, a secondary exclusion is performed to exclude slag in the converter 100 (S300). At this time, partly excluded so that the slag remains in the converter 100, or completely excluded so that no slag remains.

Next, the molten iron and scrap metal are charged into the converter 100 (S400).

Then, blown oxygen is blown into the converter 100 to remove impurities from the molten iron (S500).

When the blow is finished, the molten steel is sampled to measure the temperature of the molten steel (i.e., the end point molten steel temperature) and the component content in the molten steel. At this time, if the end point temperature of the molten steel is lower than the target molten steel end point temperature, or the measured oxygen concentration is lower than the target end point oxygen concentration, oxygen is re-strained.

Whether or not complete exhaustion is performed and whether or not re-straining is carried out is transmitted to each of the nitrogen injection amount derivation unit 400 and the coating material input derivation unit 500, and is used to derive the nitrogen injection amount and the coating material input from the next charge.

When re-straining is completed, molten steel is discharged from the converter (S600).

Table 11 is a table showing the erosion rate and the expected number of uses when the converter was coated by the method according to Comparative Examples and Examples.

Here, the erosion rate is a measure of the thickness reduction rate of the converter after use compared to the thickness of the refractory before using the converter, and each of the side walls and the bottom of the converter refractory was measured. In addition,'the number of times the converter has measured the erosion rate' means the rate of erosion of the converter measured at a specific number of uses. For example, in the case of the first converter, the erosion rate was measured when the converter was used 3940 times, and the seventh converter was measured when the converter was used 3946 times.

If the erosion rates of the side walls and the floor according to the number of times of use are measured for each converter, the erosion rates of the side walls and the floor per one use of the converter can be calculated, and if this is divided by 2, the erosion rate average can be calculated.

Estimated number of use is based on the average of the erosion rate, and the number of uses is estimated before the converter is repaired.

The erosion rate decrease value is obtained by subtracting the erosion rate average according to the comparative example from the erosion rate average according to the example, and the increase in use frequency represents the difference between the expected number of uses according to the embodiment and the expected number of uses according to the comparative example.

The converters 1 to 6 are coated with converters according to a comparative example. That is, the first to sixth converters are used for the number of converters, the oxygen concentration of the end point of the previous charge, whether or not re-straining from the previous charge, the temperature of the end point of the previous charge, whether and whether to take off the current charge, and the time to take off, and completely excluded from the previous charge Whether or not the molten steel is returned from the previous charge, the converter is coated with a constant nitrogen injection amount and a constant coating material input amount.

Then, the seventh to twelfth converters are coated with converters according to the method of implementation. That is, the seventh to twelfth converters are used for the number of converters, the end oxygen concentration of the previous charge, whether or not re-strained from the previous charge, the temperature of the endpoint of the previous charge, whether or not to perform vacancy on the current charge, and the vacancy time, and completely excluded from the previous charge Whether or not, in the previous charge, the nitrogen intake amount and the constant coating material input amount are derived according to whether or not the molten steel is transported, and the converter is coated by injecting and injecting it with the derived amount.

In addition, first and seventh converters, second and eighth converters, third and ninth converters, fourth and tenth converters, fifth and 11th converters, sixth and 12th converters It is a converter made of the same volume and the same material.

division 1st converter 2nd converter Third converter 4th converter 5th converter 6th converter Comparative example Number of converters used to measure erosion rate 3940 3269 3308 5259 3431 3378 Erosion rate average 0.166 0.170 0.143 0.106 0.144 0.173 Estimated number of available 7003 8516 8671 9126 8551 6420 division 7th converter 8th converter 9th converter 10th converter 11th converter 12th converter Example Number of converters used to measure erosion rate 3946 3556 3445 5397 3759 3335 Erosion rate average 0.148 0.140 0.122 0.101 0.130 0.169 Estimated number of available 8707 9387 10791 9244 10706 6842 Comparison of Comparative Example and Example Decreased erosion rate -0.019 -0.030 -0.020 -0.005 -0.014 -0.004 Increased use count 1704 871 2120 118 2155 422

Referring to Table 11, it can be seen that, compared to the comparative example, the average erosion rate is lower in the case of the example, thereby increasing the expected number of usable times of the converter.

As described above, according to the converter coating method according to the embodiment of the present invention, an appropriate amount of slag can be left before coating according to the number of uses of the converter and the end oxygen concentration. In addition, nitrogen intake and coating material input during converter coating are derived according to the number of use of the converter, the end point oxygen concentration, the temperature of the molten steel, and the operation process, and this is reflected in the converter coating.

Due to this, the coating efficiency and coating material of the converter inner wall are improved compared to the prior art. That is, according to the converter coating method according to the embodiment, the converter inner wall is not coated, locally coated, or the coated slag flows down again. Defects can be suppressed or prevented compared to the prior art.

Therefore, according to the converter coating method according to an embodiment of the present invention, there is an effect of extending the life of the converter.

100: converter 111: Nogu
112: Exit L: Lance
200: tilt angle derivation unit 300: tilt device
400: nitrogen injection amount derivation unit 500: coating material input derivation unit

Claims (18)

A step of deriving the tilt angle of the converter according to the number of uses of the converter in which the molten steel is discharged and the end point oxygen concentration of the former charged molten steel when the steelmaking produced in the operation process of the previous charge is completed;
Tilting the converter at the derived tilt angle to exclude a portion of the slag in the converter; And
A process of coating the inner wall of the converter by introducing a coating material into the converter and blowing nitrogen;
Including,
In blowing nitrogen into the converter,
Before nitrogen is introduced into the converter, a converter coating method for deriving a nitrogen injection amount according to the number of times the converter is used, and injecting nitrogen with the derived nitrogen injection amount. The method according to claim 1,
Before introducing the coating material into the converter, the process of deriving a coating material input amount according to the number of times the converter is used,
In the input of the coating material into the converter, the converter coating method of inputting the derived coating material. The method according to claim 2,
The process of deriving the nitrogen intake,
A process of calculating a nitrogen intake amount by adding a basic nitrogen intake amount and a plurality of nitrogen correction amounts according to the number of times the converter is used;
Comparing the calculated nitrogen intake amount with a reference nitrogen intake range; And
According to the comparison result, the calculated nitrogen injection amount is derived as the nitrogen injection amount to be injected into the converter, or the lowest nitrogen injection amount or the highest nitrogen injection amount of the reference nitrogen injection amount range is introduced into the converter. A process for deriving the nitrogen intake amount derived from the amount;
Converter coating method comprising a. The method according to claim 3,
When the calculated nitrogen injection amount is within the reference nitrogen injection amount range, the calculated nitrogen injection amount is derived as the nitrogen injection amount to be blown into the converter,
When the calculated nitrogen injection amount is less than the lowest nitrogen injection amount in the reference nitrogen injection amount range, the lower nitrogen injection amount is derived as the nitrogen injection amount to be blown into the converter,
When the calculated nitrogen injection amount exceeds the highest nitrogen injection amount in the reference nitrogen injection amount range, the converter coating method for deriving the best nitrogen injection amount as the nitrogen injection amount to be blown into the converter. The method according to claim 3,
The plurality of nitrogen correction amount,
The amount of nitrogen correction according to the end oxygen concentration of the former charged molten steel, the amount of nitrogen correction according to the end temperature of the previous charged molten steel, the amount of nitrogen correction according to the current charge operation process, and the amount of nitrogen correction according to the operation process of the previous charge Converter coating method comprising a. The method according to claim 5,
Nitrogen correction amount according to the current charge operation process,
Before or after the process of excluding a part of the slag in the converter, and includes a correction amount of nitrogen according to whether or not to carry out the odor to blow oxygen to remove the now in the converter and the vacancy time,
The nitrogen correction amount according to the operation process of the previous charge,
Nitrogen correction amount according to whether re-scaling is performed during the operation process of the previous charge, nitrogen according to whether or not complete exclusion of all slag in the converter is performed after the process of coating the inside wall of the converter during the operation process of the previous charge Correction amount, depending on whether or not the molten steel generated during the previous charging operation process is returned when coating the inner wall of the converter and charging molten iron into the converter during the operation process of the previous charge A converter coating method comprising a nitrogen correction amount. The method according to claim 6,
The basic nitrogen injection amount increases with the number of times the converter is used,
The nitrogen correction amount according to the end point oxygen concentration of the previous charge molten steel increases with the increase in the end point oxygen concentration,
The amount of nitrogen correction according to whether or not re-straining is performed during the operation process of the previous charge has a value of 0 (zero) or a constant amount (+) depending on whether it is carried out,
The amount of nitrogen correction according to the end point temperature of the previous charged molten steel increases with the increase in the end point temperature,
The amount of nitrogen correction according to whether or not the deodorization is performed and the deodorization time has a value of 0 (zero) or a positive value, and as the deodorization time increases, it increases to a positive value,
The amount of nitrogen correction according to whether or not the complete exclusion is performed has a value of 0 (zero) or a constant negative value (-) depending on whether it is carried out,
The amount of nitrogen correction according to whether the molten steel is conveyed is a converter coating method having a value of 0 (zero) or a constant amount (+) depending on whether or not it is carried out. The method according to claim 2,
The process of deriving the coating material input amount,
Calculating a coating material input amount by adding a basic coating material input amount and a plurality of coating material correction amounts according to the number of times the converter is used;
Comparing the calculated coating material input amount and the reference coating material input range; And
According to the comparison result, the calculated coating material input amount is derived as the coating material input amount to be input to the converter, or the lowest coating material input amount or the best coating material input amount of the reference coating material input range is derived as the coating material input amount to be input to the converter Derivation process;
Converter coating method comprising a. The method according to claim 8,
When the calculated coating material input amount is within the reference coating material input range, the calculated coating material input amount is derived as the coating material input amount to be input to the converter,
When the calculated coating material input amount is less than the lowest coating material input amount of the reference coating material input range, the lowest coating material input amount is derived as a coating material input amount to be input to the converter,
When the calculated coating material input amount exceeds the highest coating material input amount of the reference coating material input range, the converter coating method for deriving the best coating material input amount as the coating material input amount to be input to the converter. The method according to claim 8,
The correction amount of the plurality of coating materials,
The amount of coating material correction according to the end oxygen concentration of the former charged molten steel, the amount of coating material corrected according to the end temperature of the former charged molten steel, and the amount of coating material corrected according to the current charge operation process (Former) A converter coating method that includes the amount of coating material correction according to the operation process of charge. The method according to claim 10,
The amount of coating material correction according to the current charge operation process,
Before or after the process of excluding part of the slag in the converter, it includes whether or not to carry out the blowing to remove oxygen in the converter and remove the amount of coating material according to the taking time,
The amount of coating material correction according to the operation process of the previous charge,
The amount of coating material correction according to whether or not re-straining is performed during the operation process of the previous charge, and the coating material according to whether or not full exclusion of the slag in the converter is performed after the process of coating the inner wall of the converter during the operation process of the previous charge Corrected amount, when charging the molten iron into the converter after coating the inner wall of the converter during the operation process of the previous charge, the previous charge molten steel that is charged with the molten steel generated during the operation process of the previous charge A converter coating method including a correction amount of a coating material according to whether or not to be conveyed. The method according to claim 11,
The amount of the base coating material increases as the number of times the converter is used increases.
The amount of correction of the coating material according to the end oxygen concentration of the previous charged molten steel increases with the increase in the end oxygen concentration,
The amount of coating material correction according to whether or not re-straining is performed during the operation process of the previous charge has a value of 0 (zero) or a constant amount (+) depending on whether or not it is carried out,
The correction amount of the coating material according to the end point temperature of the previous charged molten steel increases with the increase in the end point temperature,
The amount of coating material correction according to whether or not the deodorization is performed and the deodorization time has a value of 0 (zero) or a positive value, and as the deodorization time increases, it increases to a positive value,
The amount of correction of the coating material according to whether or not the complete exclusion is performed has a value of 0 (zero) or a constant negative value (-) depending on whether or not it is carried out,
The coating material correction amount depending on whether the molten steel is conveyed is a converter coating method having a value of 0 (zero) or a constant amount (+) depending on whether or not it is carried out. The method according to any one of claims 1 to 12,
In deriving the tilt angle, the converter coating method using Equation 1.
[Equation 1]

A lance capable of introducing nitrogen into the converter;
A coating material input device located outside the converter and for introducing a coating material into the converter;
A tilt angle derivation unit for deriving a tilt angle of the converter for slag exclusion in the converter, which is carried out before coating the inner wall of the converter, according to the number of times of use of the converter and the end oxygen concentration of the former charged molten steel;
A tilting device for tilting the converter at a tilting angle derived from the tilting angle deriving unit; And
A nitrogen injection amount derivation unit for deriving a nitrogen injection amount blown into the converter for coating the converter according to the number of times the converter is used;
Including,
The lance is a molten iron treatment facility for injecting nitrogen with a nitrogen injection amount derived from the nitrogen injection amount derivation unit. The method according to claim 14,
It includes a coating material input amount deriving unit for deriving the coating material input amount into the converter for the converter coating according to the number of times the converter is used,
The coating material input device is a molten iron treatment facility for introducing the coating material into the coating material input amount derived from the coating material input amount deriving unit. The method according to claim 15,
The nitrogen injection amount deriving unit,
The nitrogen injection amount is calculated by summing the basic nitrogen injection amount and the plurality of nitrogen correction amounts according to the number of times the converter is used, and comparing the calculated nitrogen injection amount and the reference nitrogen injection amount range to calculate the calculated nitrogen injection amount. Derived by the nitrogen injection amount to be blown into the converter, or the nitrogen injection amount to derive the lowest nitrogen injection amount or the highest nitrogen injection amount of the reference nitrogen injection amount range into the converter,
The coating material input amount deriving unit,
The coating material input amount is calculated by summing the basic coating material input amount and a plurality of coating material correction amounts according to the number of times the converter is used, and comparing the calculated coating material input amount with the reference coating material input range, the calculated coating material input amount into the converter Charter treatment facility to derive the coating material input amount derived from the input amount, or from the lowest coating material input amount or the best coating material input amount of the reference coating material input range into the coating material input amount into the converter. The method according to claim 16,
Each of the plurality of nitrogen correction amount and the plurality of coating material correction amount,
Correction amount according to the end oxygen concentration of the former charge molten steel,
Correction amount according to the end temperature of the former charged molten steel,
Before or after the process of excluding part of the slag in the converter, whether or not to carry out odor to blow oxygen to remove the now in the converter and the amount of correction according to the odor time,
The amount of correction according to whether or not re-scheduling is carried out during the operation process of the previous charge,
Correction amount according to whether or not to perform complete exclusion of all slag in the converter after the process of coating the inner wall of the converter during the operation process of the previous charge,
When charging the molten iron into the converter after coating the inner wall of the converter during the operation process of the previous charge, the correction amount according to whether or not the molten steel generated during the operation process of the previous charge is returned is returned. Included charter treatment facility. The method according to any one of claims 14 to 17,
The tilt angle derivation unit is a molten iron processing facility for deriving a tilt angle using Equation 1.
[Equation 1]

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